Nearly Perfect Fluidity in a High Temperature Superconductor

DOE PAGES

Rameau, J. D.; Reber, T. J.; Yang, H. -B.; ...

2014-10-13

Perfect fluids are characterized as having the smallest ratio of shear viscosity to entropy density, η/s, consistent with quantum uncertainty and causality. So far, nearly perfect fluids have only been observed in the quark-gluon plasma and in unitary atomic Fermi gases, exotic systems that are amongst the hottest and coldest objects in the known universe, respectively. We use angle resolved photoemission spectroscopy to measure the temperature dependence of an electronic analog of η/s in an optimally doped cuprate high-temperature superconductor, finding it too is a nearly perfect fluid around, and above, its superconducting transition temperature T c.

Nearly perfect fluidity in a high-temperature superconductor

NASA Astrophysics Data System (ADS)

Rameau, J. D.; Reber, T. J.; Yang, H.-B.; Akhanjee, S.; Gu, G. D.; Johnson, P. D.; Campbell, S.

2014-10-01

Perfect fluids are characterized as having the smallest ratio of shear viscosity to entropy density, η /s, consistent with quantum uncertainty and causality. So far, nearly perfect fluids have only been observed in the quark-gluon plasma and in unitary atomic Fermi gases, exotic systems that are amongst the hottest and coldest objects in the known universe, respectively. We use angle resolved photoemission spectroscopy to measure the temperature dependence of an electronic analog of η /s in an optimally doped cuprate high-temperature superconductor, finding it too is a nearly perfect fluid around, and above, its superconducting transition temperature Tc.

Soil microbial communties and enzyme activities in soils during historically extreme drought conditions in the USA

USDA-ARS?s Scientific Manuscript database

The Southern High Plains region of Texas experienced a significant reduction in 2011 crop production due a record drought as it experienced the hottest summer since 1911 (> 48 days of temperatures above 37.7oC and only 37.8 mm precipitation). Soil microbial communities and their associated enzymatic...

Soil microbial communities and enzyme activities in soils during historically extreme drought conditions in the USA

USDA-ARS?s Scientific Manuscript database

The Southern High Plains region of Texas experienced a significant reduction in 2011 crop production due a record drought as it experienced the hottest summer since 1911 (> 48 days of temperatures above 37.7oC and only 37.8 mm precipitation). Soil microbial communities and their associated enzymati...

40 CFR Appendix Vii to Part 86 - Standard Bench Cycle (SBC)

Code of Federal Regulations, 2011 CFR

2011-07-01

... procedures [Ref. § 86.1823-08(d)] consist of aging a catalyst-oxygen-sensor system on an aging bench which... bench with an engine as the source of feed gas for the catalyst. 3. The SBC is a 60-second cycle which... occurs in the hottest catalyst. Alternatively, the feed gas temperature may be measured and converted to...

40 CFR Appendix Vii to Part 86 - Standard Bench Cycle (SBC)

Code of Federal Regulations, 2010 CFR

2010-07-01

... procedures [Ref. § 86.1823-08(d)] consist of aging a catalyst-oxygen-sensor system on an aging bench which... bench with an engine as the source of feed gas for the catalyst. 3. The SBC is a 60-second cycle which... occurs in the hottest catalyst. Alternatively, the feed gas temperature may be measured and converted to...

Tracking Climate Change through the Spatiotemporal Dynamics of the Teletherms, the Statistically Hottest and Coldest Days of the Year

DOE PAGES

Dodds, Peter Sheridan; Mitchell, Lewis; Reagan, Andrew J.; ...

2016-05-11

Instabilities and long term shifts in seasons, whether induced by natural drivers or human activities, pose great disruptive threats to ecological, agricultural, and social systems. Here, we propose, measure, and explore two fundamental markers of location-sensitive seasonal variations: the Summer and Winter Teletherms—the on-average annual dates of the hottest and coldest days of the year. We analyze daily temperature extremes recorded at 1218 stations across the contiguous United States from 1853–2012, and observe large regional variation with the Summer Teletherm falling up to 90 days after the Summer Solstice, and 50 days for the Winter Teletherm after the Winter Solstice.more » We show that Teletherm temporal dynamics are substantive with clear and in some cases dramatic shifts reflective of system bifurcations. We also compare recorded daily temperature extremes with output from two regional climate models finding considerable though relatively unbiased error. In conclusion, our work demonstrates that Teletherms are an intuitive, powerful, and statistically sound measure of local climate change, and that they pose detailed, stringent challenges for future theoretical and computational models.« less

Urban effects on extreme heat in a mid-sized North American city

NASA Astrophysics Data System (ADS)

Schatz, J.; Kucharik, C. J.

2013-12-01

As climate change drives global temperatures higher, heat waves are projected to increase in frequency, intensity, and duration, particularly in cities where the urban heat island effect can further raise local temperatures. Cities contain 50% of the global population and 80% of the North American population, and these percentages are projected to reach 70% globally and 87% in North America by 2030. This creates a need to understand the nature of heat events not just globally but also within cities where local climate variation can be substantial. That local variation could prove highly consequential for heat adaptation in cities, making it important to understand the dynamics of extreme heat within urban landscapes. Our study addresses this need by characterizing 400m-resolution variation in air temperature and heat index during a historically hot year in Madison, Wisconsin. Madison is a mid-sized temperate city with a metropolitan area population of 568,593. It is surrounded by several large lakes and a complex rural landscape of agriculture, forests, wetlands, and grasslands. In 2012, Madison experienced its hottest year and third hottest summer on record, with the Madison airport reporting 39 days exceeding 90°F compared to an average of 9 days. In March 2012, we installed 135 Onset HOBO ProV2 T/RH sensors across the Madison area to record air temperature and relative humidity at 15 minute intervals. The data from this network provides a unique opportunity to study small-scale spatial variation in the magnitude and duration of hot conditions that are projected to become more common in the future. Our sensors recorded substantial variation in the magnitude and duration of high temperatures and heat indices during the summer of 2012. For temperature, the densest parts of the city experienced >200 hours ≥90°F compared to <100 hours in many rural areas. Temperatures ≥100°F occurred up to 22 hours in some parts of the city versus 0 hours in much of the rural surroundings. For heat index, the densest parts of Madison experienced >300 hours ≥90°F compared to <200 hours in most rural areas. Heat indices ≥100°F occurred >70 hours in dense urban areas compared to <50 hours in rural. The magnitude and duration of high temperatures were positively related to percent impervious surface coverage and negatively related to lake proximity, though lake proximity was not always significant. Heat index showed similar patterns with respect to impervious cover, but unlike temperature was negatively related to water body proximity due to the lakes providing a source of high humidity. Further results and analyses will be described and visualized, including a comparison with the relatively cool and wet summer of 2013. As climate change continues to raise heat related risks in cities across the world, these results have important implications for urban adaptation to high heat and its effects on human health, electric power demand, and the environment.

Historically hottest summers projected to be the norm for more than half of the world’s population within 20 years

DOE PAGES

Mueller, Brigitte; Zhang, Xuebin; Zwiers, Francis W.

2016-04-07

We project that within the next two decades, half of the world's population will regularly (every second summer on average) experience regional summer mean temperatures that exceed those of the historically hottest summer, even under the moderate RCP4.5 emissions pathway. This frequency threshold for hot temperatures over land, which have adverse effects on human health, society and economy, might be broached in little more than a decade under the RCP8.5 emissions pathway. These hot summer frequency projections are based on adjusted RCP4.5 and 8.5 temperature projections, where the adjustments are performed with scaling factors determined by regularized optimal fingerprinting analyzesmore » that compare historical model simulations with observations over the period 1950-2012. A temperature reconstruction technique is then used to simulate a multitude of possible past and future temperature evolutions, from which the probability of a hot summer is determined for each region, with a hot summer being defined as the historically warmest summer on record in that region. Probabilities with and without external forcing show that hot summers are now about ten times more likely (fraction of attributable risk 0.9) in many regions of the world than they would have been in the absence of past greenhouse gas increases. In conclusion, the adjusted future projections suggest that the Mediterranean, Sahara, large parts of Asia and the Western US and Canada will be among the first regions for which hot summers will become the norm (i.e. occur on average every other year), and that this will occur within the next 1-2 decades.« less

Historically hottest summers projected to be the norm for more than half of the world’s population within 20 years

NASA Astrophysics Data System (ADS)

Mueller, Brigitte; Zhang, Xuebin; Zwiers, Francis W.

2016-04-01

We project that within the next two decades, half of the world’s population will regularly (every second summer on average) experience regional summer mean temperatures that exceed those of the historically hottest summer, even under the moderate RCP4.5 emissions pathway. This frequency threshold for hot temperatures over land, which have adverse effects on human health, society and economy, might be broached in little more than a decade under the RCP8.5 emissions pathway. These hot summer frequency projections are based on adjusted RCP4.5 and 8.5 temperature projections, where the adjustments are performed with scaling factors determined by regularized optimal fingerprinting analyzes that compare historical model simulations with observations over the period 1950-2012. A temperature reconstruction technique is then used to simulate a multitude of possible past and future temperature evolutions, from which the probability of a hot summer is determined for each region, with a hot summer being defined as the historically warmest summer on record in that region. Probabilities with and without external forcing show that hot summers are now about ten times more likely (fraction of attributable risk 0.9) in many regions of the world than they would have been in the absence of past greenhouse gas increases. The adjusted future projections suggest that the Mediterranean, Sahara, large parts of Asia and the Western US and Canada will be among the first regions for which hot summers will become the norm (i.e. occur on average every other year), and that this will occur within the next 1-2 decades.

Classifying Urban Space Types of Seoul using Time-series Heat Island map

NASA Astrophysics Data System (ADS)

Jung, S.; KIM, H.; JE, M.

2017-12-01

In August 2016, the hottest heat occurred in Korea since the weather observation started in Korea. Due to climate changes, this heat phenomenon is expected to be severe more in the future. Thus, this study analyzed the heatwave occurred in 2016 with regard to Seoul from various angles to identify the characteristics of urban regions where the heat island phenomenon occurred. To do this, first, temperature data for two days on August 6 and 12 in 2016 when the hottest heatwave occurred were collected from 287 places of automatic weather stations (AWS) installed in Seoul and adjacent suburbs. The temperature distribution of Seoul was mapped using interpolation in every hour using the collected temperature data. Second, regions in Seoul were classified using statistical methods based on spatial characteristics such as land coverage, density, use type, and traffic volume in Seoul. Third, a daily pattern of change in temperature in the classified regions was depicted with a graph, and regions were re-classified based on the daily pattern of change in temperature. Finally, the characteristics of the classified regions were re-reviewed and then, heat island occurrence, continuation, and reduction measure by region type were discussed. The analysis results showed that a pattern of heatwave occurrence was exhibited differently by the classified region type. The results also showed that not only physical characteristics such as land coverage but also socioeconomic index such as population density and floating population that induced a traffic volume influenced the pattern of heatwave occurrence despite of the same land usage regions. This study not only classified urban climate regions by existing mean temperature and specific time-point temperature but also proposed a methodology that analyzed heat island phenomenon inside cities by using time-series temperature data in a day. Furthermore, this study enabled regional classification based on heat island characteristics to contribute to establishment of measure for each regional classification.

The Hottest, and Most Liquid, Liquid in the Universe

NASA Astrophysics Data System (ADS)

Rajagopal, Krishna

2012-03-01

What was the universe like microseconds after the big bang? At very high temperatures, protons and neutrons fall apart --- the quarks that are ordinarily confined within them are freed. Before experiments at the Relativistic Heavy Ion Collider started recreating little droplets of big bang matter, it was thought to be a tenuous gas-like plasma. Now we know from experiments at RHIC and at the Large Hadron Collider that at these extreme temperatures nature serves up hot quark soup --- the hottest liquid in the universe and the liquid that flows with the least dissipation. The only other comparably liquid liquid is the coldest liquid in the universe, namely the fluid made of trapped fermionic atoms at microKelvin rather than TeraKelvin temperatures. These are two examples of strongly coupled fluids without any apparent quasiparticle description, a feature that they share with other phases of matter like the strange metal phase of the cuprate superconductors that aren't conventionally thought of as liquids but that are equally challenging to understand. I will describe how physicists are using RHIC and LHC experiments --- as well as calculations done using dualities between liquids and black holes discovered in string theory --- to discern the properties of hot quark soup. In this domain, string theory is answering questions posed by laboratory experiments. I will describe the opportunities and challenges for coming experiments at RHIC and the LHC, chief among them being understanding how a liquid with no apparent particulate description emerges from quarks and gluons.

Early Petrologic Processes on the Ureilite Parent Body

NASA Technical Reports Server (NTRS)

Singletary, S. J.; Grove, T. L.

2003-01-01

We present a petrographic and petrologic analysis of 21 olivine-pigeonite ureilites, along with new experimental results on melt compositions predicted to be in equilibrium with ureilite compositions. We conclude that these ureilites are the residues of a partial melting/smelting event. Textural evidence preserved in olivine and pigeonite record the extent of primary smelting. In pigeonite cores, we observe fine trains of iron metal inclusions that formed by the reduction of olivine to pigeonite and metal during primary smelting. Olivine cores lack metal inclusions but the outer grain boundaries are variably reduced by a late-stage reduction event. The modal proportion of pigeonite and percentage of olivine affected by late stage reduction are inversely related and provide an estimation of the degree of primary smelting during ureilite petrogenesis. In our sample suite, this correlation holds for 16 of the 21 samples examined. Olivine-pigeonite-liquid phase equilibrium constraints are used to obtain temperature estimates for the ureilite samples examined. Inferred smelting temperatures range from approximately 1150 C to just over 1300 C and span the range of estimates published for ureilites containing two or more pyroxenes. Temperature is also positively correlated with modal percent pigeonite. Smelting temperature is inversely correlated with smelting depth--the hottest olivine-pigeonite ureilites coming from the shallowest depth in the ureilite parent body. The highest temperature samples also have oxygen isotopic signatures that fall toward the refractory inclusion-rich end of the carbonaceous chondrite-anhydrous mineral (CCAM) slope 1 mixing line. These temperature-depth variations in the ureilite parent body could have been created by a heterogeneous distribution of heat producing elements, which would indicate that isotopic heterogeneities existed in the material from which the ureilite parent body was assembled.

Materials review for improved automotive gas turbine engine. [superalloys, refractory alloys, and ceramics

NASA Technical Reports Server (NTRS)

Belleau, C.; Ehlers, W. L.; Hagen, F. A.

1978-01-01

The potential role of superalloys, refractory alloys, and ceramics in the hottest sections of engines operating with turbine inlet temperatures as high as 1370 C is examined. The convential superalloys, directionally solidified eutectics, oxide dispersion strenghened alloys, and tungsten fiber reinforced superalloys are reviewed and compared on the basis of maximum turbine blade temperature capability. Improved high temperature protective coatings and special fabrication techniques for these advanced alloys are discussed. Chromium, columbium, molybdenum, tantalum, and tungsten alloys are also reviewed. Molbdenum alloys are found to be the most suitable for mass produced turbine wheels. Various forms and fabrication processes for silicon nitride, silicon carbide, and SIALON's are investigated for use in highstress and medium stress high temperature environments.

Piezothermal effect in a spinning gas

NASA Astrophysics Data System (ADS)

Geyko, V. I.; Fisch, N. J.

2016-10-01

A spinning gas, heated adiabatically through axial compression, is known to exhibit a rotation-dependent heat capacity. However, as equilibrium is approached, an effect is identified here wherein the temperature does not grow homogeneously in the radial direction, but develops a temperature differential with the hottest region on axis, at the maximum of the centrifugal potential energy. This phenomenon, which we call a piezothermal effect, is shown to grow bilinearly with the compression rate and the amplitude of the potential. Numerical simulations confirm a simple model of this effect, which can be generalized to other forms of potential energy and methods of heating.

Chemical kinetics on extrasolar planets.

PubMed

Moses, Julianne I

2014-04-28

Chemical kinetics plays an important role in controlling the atmospheric composition of all planetary atmospheres, including those of extrasolar planets. For the hottest exoplanets, the composition can closely follow thermochemical-equilibrium predictions, at least in the visible and infrared photosphere at dayside (eclipse) conditions. However, for atmospheric temperatures approximately <2000K, and in the uppermost atmosphere at any temperature, chemical kinetics matters. The two key mechanisms by which kinetic processes drive an exoplanet atmosphere out of equilibrium are photochemistry and transport-induced quenching. I review these disequilibrium processes in detail, discuss observational consequences and examine some of the current evidence for kinetic processes on extrasolar planets.

The 10 Hottest Technologies in Telecom.

ERIC Educational Resources Information Center

Flanagan, Patrick

1997-01-01

Presents the fourth annual listing of the 10 "hottest" telecommunications technologies. Describes Web broadcasting, remote-access servers, extranets, Internet telephony, enterprise network directory services, Web site management tools, IP (Internet Protocols) switching, wavelength division multiplexing, digital subscriber lines, and…

ASCA X-ray observations of pre-main-sequence stars

NASA Technical Reports Server (NTRS)

Skinner, S. L.; Walter, F. M.; Yamauchi, S.

1996-01-01

The results of recent Advanced Satellite for Cosmology and Astrophysics (ASCA) X-ray observations of two pre-main sequence stars are presented: the weak emission line T Tauri star HD 142361, and the Herbig Ae star HD 104237. The solid state imaging spectrometer spectra for HD 142361 shows a clear emission line from H-like Mg 7, and spectral fits reveal a multiple temperature plasma with a hot component of at least 16 MK. The spectra of HD 104237 show a complex temperature structure with the hottest plasma at temperatures of greater than 30 MK. It is concluded that mechanisms that predict only soft X-ray emission can be dismissed for Herbig Ae stars.

Historical warnings of future food insecurity with unprecedented seasonal heat.

PubMed

Battisti, David S; Naylor, Rosamond L

2009-01-09

Higher growing season temperatures can have dramatic impacts on agricultural productivity, farm incomes, and food security. We used observational data and output from 23 global climate models to show a high probability (>90%) that growing season temperatures in the tropics and subtropics by the end of the 21st century will exceed the most extreme seasonal temperatures recorded from 1900 to 2006. In temperate regions, the hottest seasons on record will represent the future norm in many locations. We used historical examples to illustrate the magnitude of damage to food systems caused by extreme seasonal heat and show that these short-run events could become long-term trends without sufficient investments in adaptation.

Blacker than Black Artist Concept

NASA Image and Video Library

2007-05-09

This artist concept illustrates the hottest planet yet observed in the universe. The scorching ball of gas, a hot Jupiter called HD 149026b, is about 3 times hotter than the rocky surface of Venus, the hottest planet in our solar system.

Scanning electron microscope observations of sublimates from Merapi Volcano, Indonesia

USGS Publications Warehouse

Symonds, R.

1993-01-01

Sublimates were sampled from high-temperature (up to 800??C) fumaroles at Merapi volcano in January 1984. Sampling is accomplished by inserting silica tubes into high-temperature vents. Volcanic glass flows through the tubes and sublimates precipitate on the inner walls in response to the temperature gradient. With decreasing temperature (800-500??C) in the tubes, there are five sublimate zones. Texturally, the sublimate phases grade from large, well-formed crystals at their highest-temperature occurrence to more numerous, smaller crystals that are less perfect at lower temperatures. These changes imply that the crystal nucleation and growth rates increase and decrease, respectively, as temperature decreases. Overall, the textural data suggest that the gas is saturated or slightly super-saturated with the phases at their hottest occurrence, but that the gas becomes increasingly super-saturated with the phases at lower temperatures. -from Author

Nuisance or Not? Part 2 "Wood" New Additives Make a Difference?

NASA Astrophysics Data System (ADS)

Vilardi, J. R.

2017-12-01

Nuisance or Not? Part 2"Wood" New Additives Make a Difference? Julian Vilardi Wetumpka Middle School, Wetumpka, USA Last year fuel briquettes were created out of nuisance organisms. Several samples had results better or comparable to the controls. This project is a revision/ extension. Purpose: Find process and formula for a long lasting environmentally friendly biofuel that produces high energy with low byproducts and low cost. Hypotheses: If wisteria is processed to make a biofuel that contains 90% wisteria leaves and vines and 10% pine cones, then a high energy, low byproduct, biofuel will be created. Procedure: Collect, dry and chop material, compress mass, burn test, repeat for every organism. Kudzu was combined in a 70 % kudzu: 30 % wood additive with used cooking oil and pressed into logs. Logs were massed, burned and temperature was recorded and compared to controls. Results: Kudzu had the longest flame but produced smoke. Kudzu logs with recycled cooking oil had less smoke and burned for an hour plus. Conclusions: Wisteria did not compact or have great flammability. Pine cones did not flame well either. This hypothesis was unsupported. All kudzu samples when compacted and combined with any additive were the best biofuel. Kudzu logs with the mixture of wood additives burned the longest and was one of the hottest. The gas chromatograph/emissions tests showed the organic byproducts produced on burning the kudzu logs were less than the accepted range for air quality. These supported the hypothesis and met the purpose of this project. A low cost, environmentally friendly, efficient fuel source was created!

Herschel Observations of Extraordinary Sources: Analysi sof the HIFI 1.2 THz Wide Spectral Survey toward Orion KL II. Chemical Implications

NASA Astrophysics Data System (ADS)

Crockett, N. R.; Bergin, E. A.; Neill, J. L.; Favre, C.; Blake, G. A.; Herbst, E.; Anderson, D. E.; Hassel, G. E.

2015-06-01

We present chemical implications arising from spectral models fit to the Herschel/HIFI spectral survey toward the Orion Kleinmann-Low nebula (Orion KL). We focus our discussion on the eight complex organics detected within the HIFI survey utilizing a novel technique to identify those molecules emitting in the hottest gas. In particular, we find the complex nitrogen bearing species CH3CN, C2H3CN, C2H5CN, and NH2CHO systematically trace hotter gas than the oxygen bearing organics CH3OH, C2H5OH, CH3OCH3, and CH3OCHO, which do not contain nitrogen. If these complex species form predominantly on grain surfaces, this may indicate N-bearing organics are more difficult to remove from grain surfaces than O-bearing species. Another possibility is that hot (Tkin ∼ 300 K) gas phase chemistry naturally produces higher complex cyanide abundances while suppressing the formation of O-bearing complex organics. We compare our derived rotation temperatures and molecular abundances to chemical models, which include gas-phase and grain surface pathways. Abundances for a majority of the detected complex organics can be reproduced over timescales ≳105 years, with several species being underpredicted by less than 3σ. Derived rotation temperatures for most organics, furthermore, agree reasonably well with the predicted temperatures at peak abundance. We also find that sulfur bearing molecules that also contain oxygen (i.e., SO, SO2, and OCS) tend to probe the hottest gas toward Orion KL, indicating the formation pathways for these species are most efficient at high temperatures. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Vapor generator steam drum spray head

DOEpatents

Fasnacht, Jr., Floyd A.

1978-07-18

A typical embodiment of the invention provides a combination feedwater and "cooldown" water spray head that is centrally disposed in the lower portion of a nuclear power plant steam drum. This structure not only discharges the feedwater in the hottest part of the steam drum, but also increases the time required for the feedwater to reach the steam drum shell, thereby further increasing the feedwater temperature before it contacts the shell surface, thus reducing thermal shock to the steam drum structure.

Piezothermal effect in a spinning gas

DOE PAGES

Geyko, V. I.; Fisch, N. J.

2016-10-13

A spinning gas, heated adiabatically through axial compression, is known to exhibit a rotation-dependent heat capacity. However, as equilibrium is approached, an effect is identified here wherein the temperature does not grow homogeneously in the radial direction, but develops a temperature differential with the hottest region on axis, at the maximum of the centrifugal potential energy. This phenomenon, which we call a piezothermal effect, is shown to grow bilinearly with the compression rate and the amplitude of the potential. As a result, numerical simulations confirm a simple model of this effect, which can be generalized to other forms of potentialmore » energy and methods of heating.« less

Quantifying the influence of global warming on unprecedented extreme climate events

PubMed Central

Singh, Deepti; Horton, Daniel E.; Swain, Daniel L.; Touma, Danielle; Charland, Allison; Liu, Yunjie; Haugen, Matz; Tsiang, Michael; Rajaratnam, Bala

2017-01-01

Efforts to understand the influence of historical global warming on individual extreme climate events have increased over the past decade. However, despite substantial progress, events that are unprecedented in the local observational record remain a persistent challenge. Leveraging observations and a large climate model ensemble, we quantify uncertainty in the influence of global warming on the severity and probability of the historically hottest month, hottest day, driest year, and wettest 5-d period for different areas of the globe. We find that historical warming has increased the severity and probability of the hottest month and hottest day of the year at >80% of the available observational area. Our framework also suggests that the historical climate forcing has increased the probability of the driest year and wettest 5-d period at 57% and 41% of the observed area, respectively, although we note important caveats. For the most protracted hot and dry events, the strongest and most widespread contributions of anthropogenic climate forcing occur in the tropics, including increases in probability of at least a factor of 4 for the hottest month and at least a factor of 2 for the driest year. We also demonstrate the ability of our framework to systematically evaluate the role of dynamic and thermodynamic factors such as atmospheric circulation patterns and atmospheric water vapor, and find extremely high statistical confidence that anthropogenic forcing increased the probability of record-low Arctic sea ice extent. PMID:28439005

Quantifying the influence of global warming on unprecedented extreme climate events.

PubMed

Diffenbaugh, Noah S; Singh, Deepti; Mankin, Justin S; Horton, Daniel E; Swain, Daniel L; Touma, Danielle; Charland, Allison; Liu, Yunjie; Haugen, Matz; Tsiang, Michael; Rajaratnam, Bala

2017-05-09

Efforts to understand the influence of historical global warming on individual extreme climate events have increased over the past decade. However, despite substantial progress, events that are unprecedented in the local observational record remain a persistent challenge. Leveraging observations and a large climate model ensemble, we quantify uncertainty in the influence of global warming on the severity and probability of the historically hottest month, hottest day, driest year, and wettest 5-d period for different areas of the globe. We find that historical warming has increased the severity and probability of the hottest month and hottest day of the year at >80% of the available observational area. Our framework also suggests that the historical climate forcing has increased the probability of the driest year and wettest 5-d period at 57% and 41% of the observed area, respectively, although we note important caveats. For the most protracted hot and dry events, the strongest and most widespread contributions of anthropogenic climate forcing occur in the tropics, including increases in probability of at least a factor of 4 for the hottest month and at least a factor of 2 for the driest year. We also demonstrate the ability of our framework to systematically evaluate the role of dynamic and thermodynamic factors such as atmospheric circulation patterns and atmospheric water vapor, and find extremely high statistical confidence that anthropogenic forcing increased the probability of record-low Arctic sea ice extent.

Quantifying the Influence of Global Warming on Unprecedented Extreme Climate Events

NASA Technical Reports Server (NTRS)

Diffenbaugh, Noah S.; Singh, Deepti; Mankin, Justin S.; Horton, Daniel E.; Swain, Daniel L.; Touma, Danielle; Charland, Allison; Liu, Yunjie; Haugen, Matz; Tsiang, Michael;

Differences in Landsat TM derived lava flow thermal structures during summit and flank eruption at Mount Etna

NASA Astrophysics Data System (ADS)

Lombardo, V.; Buongiorno, M. F.; Pieri, D.; Merucci, L.

2004-06-01

The simultaneous solution of the Planck equation (the so-called "dual-band" technique) for two shortwave infrared Landsat Thematic Mapper (TM) bands allows an estimate of the fractional area of the hottest part of an active flow and the temperature of the cooler crust. Here, the dual-band method has been applied to a time series of Mount Etna eruptions. The frequency distribution of the fractional area of the hottest component reveals specific differences between summit and flank lava flows. The shape of the density function shows a trend consistent with a Gaussian distribution and suggests a relationship between the moments of the distribution and the emplacement environment. Because flow composition of Etnean lavas generally remains constant during the duration of their emplacement, it appears that the shape of any particular frequency distribution is probably related to fluid mechanical aspects of flow emplacement that affect flow velocity and flow heat loss and thus the rate of formation of the surface crust. These factors include the influence of topographical features such as changes in slope gradient, changes in volume effusion rate, and progressive downflow increases in bulk or effective viscosity. A form of the general theoretical solution for the 'dual-band' system, which illustrates the relationship between radiance in TM bands 5 and 7, corresponding to hot fractional area and crust temperature, is presented. Generally speaking, it appears that for a given flow at any point in time, larger fractional areas of exposed hot material are correlated with higher temperatures and that, while the overall shape of that distribution is common for the flows studied, its amplitude and slope reflect individual flow rheological regimes.

Transits and Eclipses of the Best of the Best: 23 Hot Jupiters for Atmospheric Characterization by Spitzer, Hubble, and JWST

NASA Astrophysics Data System (ADS)

Deming, Drake; Benneke, Bjoern; Fraine, Jonathan; Kataria, Tiffany; Knutson, Heather; Lewis, Nikole; Madhusudhan, Nikku; Mandell, Avi; McCullough, Peter; Sheppard, Kyle; Sing, David; Stevenson, Kevin; Todorov, Kamen; Wakeford, Hannah; Wilkins, Ashlee; Burrows, Adam

2016-08-01

We propose a program of Spitzer transit and secondary eclipse observations for 23 of the 'best of the best' hot giant planets (R > 0.8 Jupiters). We focus on planets that are already observed by HST, proposed to be observed by HST, or candiates for JWST Early Release Science observations. Our eclipse observations will measure day side temperatures that are needed for HST spectroscopy, and temperatures of the hottest and most favorable planets for JWST spectroscopy and possible phase curve observations. Several of our planets are extremely inflated, with atmospheric scale heights exceeding a thousand kilometers, yielding large atmospheric signatures during transit. Our transit photometry has the potential to detect molecular absorption by comparing transit radii and eclipse depths in the two Spitzer bands. Moreover, our precise transit depths will help to evaluate the magnitude of continuous opacity in the exoplanetary atmospheres, breaking the degeneracy between composition and cloud opacity, as recently demonstrated by Sing et al. We will thereby find the hottest and clearest giant exoplanetary atmospheres, with the largest molecular signatures, for HST and JWST spectroscopy. This will complete the Spitzer hot Jupiter legacy by providing a uniform set of transit and eclipse observations for the most favorable members of the intriguing population of close-in highly-irradiated giant planets. This unique Spitzer data set will guide efforts toward detailed atmospheric characterization of individual hot Jupiters for years to come.

Human biometeorological analysis of the thermal conditions of the hot Turkish city of Şanliurfa

NASA Astrophysics Data System (ADS)

Toy, Süleyman; Aytaç, Ahmet Serdar; Kántor, Noémi

2018-01-01

This paper offers a throughout human biometeorological assessment about the thermal conditions of Şanliurfa in one of the hottest parts of Turkey, in the hottest period of the year (from April to October), and a comparative analysis of three built-up types (urban, suburban and rural). Therefore, the values of physiologically equivalent temperature (PET), one of the most extensively used indices, were calculated from basic climate data with the help of the RayMan model. It was found by regarding the resulted mean PET values and the occurrence frequency of extreme heat stress periods (PET values above 41 °C) that the urban area exhibited the most unfavourable properties, followed by the suburban and rural areas. We also found very severe heat stress conditions in the summer, which may be explained by the torrid and arid climate, calm air conditions and the lack of abundant vegetation. Aiming to optimise human thermal conditions, thereby improving local life quality and facilitating international tourism, increment of vegetated areas and water surfaces would be required and, of course, highlighting the traditional methods taking into account the important aspects of sustainability.

Chandra Observations of the Eclipsing Wolf-Rayet Binary CQ CepOver a Full Orbital Cycle

NASA Astrophysics Data System (ADS)

Skinner, Steve L.; Guedel, Manuel; Schmutz, Werner; Zhekov, Svetozar

2018-06-01

We present results of Chandra X-ray observations and simultaneous optical light curves of the short-period (1.64 d) eclipsing WN6+O9 binary system CQ Cep obtained in 2013 and 2017 covering a full binary orbit. Our primary objective was to compare the observed X-ray properties with colliding wind shock theory, which predicts that the hottest shock plasma (T > 20 MK) will form on or near the line-of-centers between the stars. Thus, X-ray variability is expected during eclipses when the hottest plasma is occulted. The X-ray spectrum is strikingly similar to apparently single WN6 stars such as WR 134 and spectral lines reveal plasma over a broad range of temperatures T ~ 4 - 40 MK. Both primary and secondary optical eclipses were clearly detected and provide an accurate orbital period determination (P = 1.6412 d). The X-ray emission remained remarkably steady throughout the orbit and statistical tests give a low probability of variability. The lack of significant X-ray variabililty during eclipses indicates that the X-ray emission is not confined along the line-of-centers but is extended on larger spatial scales, contrary to colliding wind predictions.

The use of fire and human distribution

PubMed Central

MacDonald, Katharine

2017-01-01

ABSTRACT Humans today live in a wide range of environments from the iciest to the hottest, thanks to diverse cultural solutions that buffer temperature extremes. The prehistory of this relationship between human distribution, cultural solutions and temperature conditions may help us to understand the evolution of human biological adaptations to cold temperature. Fire has long been seen as an important factor in human evolution and range expansion, particularly into temperate latitudes. Nevertheless, the earliest evidence for hominin presence in Eurasia, and middle latitudes in northern Europe, substantially predates convincing evidence for fire use in these regions. This review outlines the current state of knowledge of the chronology of hominin dispersal into temperate latitudes, from the earliest occupants to our own species, and the archeological evidence for fire use. Given continuing disagreement about this chronology and limitations to the archeological evidence, new, complementary approaches are worthwhile and would benefit from information from studies of current human temperature regulation. PMID:28680931

Discriminating fever behavior in house flies.

PubMed

Anderson, Robert D; Blanford, Simon; Jenkins, Nina E; Thomas, Matthew B

2013-01-01

Fever has generally been shown to benefit infected hosts. However, fever temperatures also carry costs. While endotherms are able to limit fever costs physiologically, the means by which behavioral thermoregulators constrain these costs are less understood. Here we investigated the behavioral fever response of house flies (Musca domestica L.) challenged with different doses of the fungal entomopathogen, Beauveria bassiana. Infected flies invoked a behavioral fever selecting the hottest temperature early in the day and then moving to cooler temperatures as the day progressed. In addition, flies infected with a higher dose of fungus exhibited more intense fever responses. These variable patterns of fever are consistent with the observation that higher fever temperatures had greater impact on fungal growth. The results demonstrate the capacity of insects to modulate the degree and duration of the fever response depending on the severity of the pathogen challenge and in so doing, balance the costs and benefits of fever.

LDMOS Channel Thermometer Based on a Thermal Resistance Sensor for Balancing Temperature in Monolithic Power ICs.

PubMed

Lin, Tingyou; Ho, Yingchieh; Su, Chauchin

2017-06-15

This paper presents a method of thermal balancing for monolithic power integrated circuits (ICs). An on-chip temperature monitoring sensor that consists of a poly resistor strip in each of multiple parallel MOSFET banks is developed. A temperature-to-frequency converter (TFC) is proposed to quantize on-chip temperature. A pulse-width-modulation (PWM) methodology is developed to balance the channel temperature based on the quantization. The modulated PWM pulses control the hottest of metal-oxide-semiconductor field-effect transistor (MOSFET) bank to reduce its power dissipation and heat generation. A test chip with eight parallel MOSFET banks is fabricated in TSMC 0.25 μm HV BCD processes, and total area is 900 × 914 μm². The maximal temperature variation among the eight banks can reduce to 2.8 °C by the proposed thermal balancing system from 9.5 °C with 1.5 W dissipation. As a result, our proposed system improves the lifetime of a power MOSFET by 20%.

LDMOS Channel Thermometer Based on a Thermal Resistance Sensor for Balancing Temperature in Monolithic Power ICs

PubMed Central

Lin, Tingyou; Ho, Yingchieh; Su, Chauchin

2017-01-01

This paper presents a method of thermal balancing for monolithic power integrated circuits (ICs). An on-chip temperature monitoring sensor that consists of a poly resistor strip in each of multiple parallel MOSFET banks is developed. A temperature-to-frequency converter (TFC) is proposed to quantize on-chip temperature. A pulse-width-modulation (PWM) methodology is developed to balance the channel temperature based on the quantization. The modulated PWM pulses control the hottest of metal-oxide-semiconductor field-effect transistor (MOSFET) bank to reduce its power dissipation and heat generation. A test chip with eight parallel MOSFET banks is fabricated in TSMC 0.25 μm HV BCD processes, and total area is 900 × 914 μm2. The maximal temperature variation among the eight banks can reduce to 2.8 °C by the proposed thermal balancing system from 9.5 °C with 1.5 W dissipation. As a result, our proposed system improves the lifetime of a power MOSFET by 20%. PMID:28617346

PID temperature controller in pig nursery: spatial characterization of thermal environment

NASA Astrophysics Data System (ADS)

de Souza Granja Barros, Juliana; Rossi, Luiz Antonio; Menezes de Souza, Zigomar

2018-05-01

The use of enhanced technologies of temperature control can improve the thermal conditions in environments of livestock facilities. The objective of this study was to evaluate the spatial distribution of the thermal environment variables in a pig nursery with a heating system with two temperature control technologies based on the geostatistical analysis. The following systems were evaluated: overhead electrical resistance with Proportional, Integral, and Derivative (PID) controller and overhead electrical resistance with a thermostat. We evaluated the climatic variables: dry bulb temperature (Tbs), air relative humidity (RH), temperature and humidity index (THI), and enthalpy in the winter, at 7:00, 12:00, and 18:00 h. The spatial distribution of these variables was mapped by kriging. The results showed that the resistance heating system with PID controllers improved the thermal comfort conditions in the pig nursery in the coldest hours, maintaining the spatial distribution of the air temperature more homogeneous in the pen. During the hottest weather, neither system provided comfort.

PID temperature controller in pig nursery: spatial characterization of thermal environment

NASA Astrophysics Data System (ADS)

de Souza Granja Barros, Juliana; Rossi, Luiz Antonio; Menezes de Souza, Zigomar

2017-11-01

The use of enhanced technologies of temperature control can improve the thermal conditions in environments of livestock facilities. The objective of this study was to evaluate the spatial distribution of the thermal environment variables in a pig nursery with a heating system with two temperature control technologies based on the geostatistical analysis. The following systems were evaluated: overhead electrical resistance with Proportional, Integral, and Derivative (PID) controller and overhead electrical resistance with a thermostat. We evaluated the climatic variables: dry bulb temperature (Tbs), air relative humidity (RH), temperature and humidity index (THI), and enthalpy in the winter, at 7:00, 12:00, and 18:00 h. The spatial distribution of these variables was mapped by kriging. The results showed that the resistance heating system with PID controllers improved the thermal comfort conditions in the pig nursery in the coldest hours, maintaining the spatial distribution of the air temperature more homogeneous in the pen. During the hottest weather, neither system provided comfort.

Fluidized bed heating process and apparatus

NASA Technical Reports Server (NTRS)

McHale, Edward J. (Inventor)

1981-01-01

Capacitive electrical heating of a fluidized bed enables the individual solid particles within the bed to constitute the hottest portion thereof. This effect is achieved by applying an A. C. voltage potential between dielectric coated electrodes, one of which is advantageously the wall of the fluidized bed rejection zone, sufficient to create electrical currents in said particles so as to dissipate heat therein. In the decomposition of silane or halosilanes in a fluidized bed reaction zone, such heating enhances the desired deposition of silicon product on the surface of the seed particles within the fluidized bed and minimizes undesired coating of silicon on the wall of the reaction zone and the homogeneous formation of fine silicon powder within said zone.

The science and application of forest carbon projects

Treesearch

Robert J. Moulton

2002-01-01

This year-1999, now in its 7th month-is well on its way to becoming the hottest year in what has already been documented as the hottest decade on record both in the United States and worldwide. This makes a good setting for discussing global climate change, a much better setting than, say, the second week of a record-setting cold spell in February, 1999 when some...

Temperature Effects on Labor in Latin America

NASA Astrophysics Data System (ADS)

Foreman, T.

2016-12-01

It has long been known that environmental conditions can affect humans' performance of various tasks, both physical and mental. In light of projected climate change, heat's impact on performance is of particular concern. While there is evidence that performance suffers, from an economic standpoint, how this performance effect changes a worker's ability or willingness to work is of particular concern. Workers' decisions to supply less labor may be a key channel for economic losses due to climate change, especially in developing countries that experience high temperatures and humidity. In a study of worker behavior in Guatemala, Mexico, and Nicaragua, increasing temperatures by 1°C was found to reduce labor supplied by up to an hour per day for each worker on average in the poorest and hottest places. This result holds across different levels of risk exposure to heat, indicating little evidence of potential adaptation measures.

Aerosol effect on climate extremes in Europe under different future scenarios

NASA Astrophysics Data System (ADS)

Sillmann, J.; Pozzoli, L.; Vignati, E.; Kloster, S.; Feichter, J.

2013-05-01

This study investigates changes in extreme temperature and precipitation events under different future scenarios of anthropogenic aerosol emissions (i.e., SO2 and black and organic carbon) simulated with an aerosol-climate model (ECHAM5-HAM) with focus on Europe. The simulations include a maximum feasible aerosol reduction (MFR) scenario and a current legislation emission (CLEmod) scenario where Europe implements the MFR scenario, but the rest of the world follows the current legislation scenario and a greenhouse gas scenario. The strongest changes relative to the year 2000 are projected for the MFR scenario, in which the global aerosol reduction greatly enforces the general warming effect due to greenhouse gases and results in significant increases of temperature and precipitation extremes in Europe. Regional warming effects can also be identified from aerosol reductions under the CLEmodscenario. This becomes most obvious in the increase of the hottest summer daytime temperatures in Northern Europe.

A Statistical Approach to Exoplanetary Molecular Spectroscopy Using Spitzer Eclipses

NASA Astrophysics Data System (ADS)

Deming, Drake; Garhart, Emily; Burrows, Adam; Fortney, Jonathan; Knutson, Heather; Todorov, Kamen

2018-01-01

Secondary eclipses of exoplanets observed using the Spitzer Space Telescope measure the total emission emergent from exoplanetary atmospheres integrated over broad photometric bands. Spitzer photometry is excellent for measuring day side temperatures, but is less well suited to the detection of molecular absorption or emission features. Even for very hot exoplanets, it can be difficult to attain the accuracy on eclipse depth that is needed to unambiguously interpret the Spitzer results in terms of molecular absorption or emission. However, a statistical approach, wherein we seek deviations from a simple blackbody planet as a function of the planet's equilibrium temperature, shows promise for defining the nature and strength of molecular absorption in ensembles of planets. In this paper, we explore such an approach using secondary eclipses observed for tens of hot exoplanets during Spitzer's Cycles 10, 12, and 13. We focus on the possibility that the hottest planets exhibit molecular features in emission, due to temperature inversions.

Hot Talk, Cold Science

NASA Astrophysics Data System (ADS)

Oglesby, Robert J.

One of the hottest topics in climate science is understanding and evaluating the impacts of possible global warming caused by anthropogenic emissions of greenhouse gases. In Hot Talk, Cold Science, S. Fred Singer does not accept global warming. Singer says in his preface, “The purpose of this book is to demonstrate that the evidence [for global warming] is neither settled, nor compelling, nor even convincing. On the contrary, scientists continue to discover new mechanisms for climate change and to put forth new theories to try to account for the fact that global temperature is not rising, even though greenhouse theory says it should”.

Quark Gluon Plasma

ScienceCinema

Lincoln, Don

2018-01-16

Matter is malleable and can change its properties with temperature. This is most familiar when comparing ice, liquid water and steam, which are all different forms of the same thing. However beyond the usual states of matter, physicists can explore other states, both much colder and hotter. In this video, Fermilab’s Dr. Don Lincoln explains the hottest known state of matter – a state that is so hot that protons and neutrons from the center of atoms can literally melt. This form of matter is called a quark gluon plasma and it is an important research topic being pursued at the LHC.

O stars and Wolf-Rayet stars

NASA Technical Reports Server (NTRS)

Conti, Peter S.; Underhill, Anne B.; Jordan, Stuart (Editor); Thomas, Richard (Editor)

1988-01-01

Basic information is given about O and Wolf-Rayet stars indicating how these stars are defined and what their chief observable properties are. Part 2 of the volume discussed four related themes pertaining to the hottest and most luminous stars. Presented are: an observational overview of the spectroscopic classification and extrinsic properties of O and Wolf-Rayet stars; the intrinsic parameters of luminosity, effective temperature, mass, and composition of the stars, and a discussion of their viability; stellar wind properties; and the related issues concerning the efforts of stellar radiation and wind on the immediate interstellar environment are presented.

The Origin of the Moon Within a Terrestrial Synestia

NASA Astrophysics Data System (ADS)

Lock, Simon J.; Stewart, Sarah T.; Petaev, Michail I.; Leinhardt, Zoë; Mace, Mia T.; Jacobsen, Stein B.; Cuk, Matija

2018-04-01

The giant impact hypothesis remains the leading theory for lunar origin. However, current models struggle to explain the Moon's composition and isotopic similarity with Earth. Here we present a new lunar origin model. High-energy, high-angular-momentum giant impacts can create a post-impact structure that exceeds the corotation limit, which defines the hottest thermal state and angular momentum possible for a corotating body. In a typical super-corotation-limit body, traditional definitions of mantle, atmosphere, and disk are not appropriate, and the body forms a new type of planetary structure, named a synestia. Using simulations of cooling synestias combined with dynamic, thermodynamic, and geochemical calculations, we show that satellite formation from a synestia can produce the main features of our Moon. We find that cooling drives mixing of the structure, and condensation generates moonlets that orbit within the synestia, surrounded by tens of bars of bulk silicate Earth vapor. The moonlets and growing moon are heated by the vapor until the first major element (Si) begins to vaporize and buffer the temperature. Moonlets equilibrate with bulk silicate Earth vapor at the temperature of silicate vaporization and the pressure of the structure, establishing the lunar isotopic composition and pattern of moderately volatile elements. Eventually, the cooling synestia recedes within the lunar orbit, terminating the main stage of lunar accretion. Our model shifts the paradigm for lunar origin from specifying a certain impact scenario to achieving a Moon-forming synestia. Giant impacts that produce potential Moon-forming synestias were common at the end of terrestrial planet formation.

Radiative temperature measurements at Kupaianaha lava lake, Kilauea Volcano, Hawaii

NASA Technical Reports Server (NTRS)

Flynn, Luke P.; Mouginis-Mark, Peter J.; Gradie, Jonathan C.; Lucey, Paul G.

1993-01-01

The radiative temperature of the surface of Kupaianaha lava lake is computed using field spectroradiometer data. Observations were made during periods of active overturning. The lake surface exhibits three stages of activity. Magma fountaining and overturning events characterize stage 1, which exhibits the hottest crustal temperatures and the largest fractional hot areas. Rifting events between plates of crust mark stage 2; crustal temperatures in this stage are between 100 C and 340 C, and fractional hot areas are at least an order of magnitude smaller than those in stage 1. Stage 3 is characterized by quiescent periods when the lake is covered by a thick crust. This stage dominates the activity of the lake more than 90 percent of the time. The results of this study are relevant for satellite and airborne measurement of the thermal characteristics of active volcanoes, and indicate that the thermal output of a lava lake varies on a time scale of seconds to minutes.

SLAC All Access: Fermi Gamma-ray Space Telescope

ScienceCinema

Romani, Roger

2018-04-16

Three hundred and fifty miles overhead, the Fermi Gamma-ray Space Telescope silently glides through space. From this serene vantage point, the satellite's instruments watch the fiercest processes in the universe unfold. Pulsars spin up to 700 times a second, sweeping powerful beams of gamma-ray light through the cosmos. The hyperactive cores of distant galaxies spew bright jets of plasma. Far beyond, something mysterious explodes with unfathomable power, sending energy waves crashing through the universe. Stanford professor and KIPAC member Roger W. Romani talks about this orbiting telescope, the most advanced ever to view the sky in gamma rays, a form of light at the highest end of the energy spectrum that's created in the hottest regions of the universe.

Determining mode excitations of vacuum electronics devices via three-dimensional simulations using the SOS code

NASA Technical Reports Server (NTRS)

Warren, Gary

1988-01-01

The SOS code is used to compute the resonance modes (frequency-domain information) of sample devices and separately to compute the transient behavior of the same devices. A code, DOT, is created to compute appropriate dot products of the time-domain and frequency-domain results. The transient behavior of individual modes in the device is then plotted. Modes in a coupled-cavity traveling-wave tube (CCTWT) section excited beam in separate simulations are analyzed. Mode energy vs. time and mode phase vs. time are computed and it is determined whether the transient waves are forward or backward waves for each case. Finally, the hot-test mode frequencies of the CCTWT section are computed.

European summer heatwaves and North Atlantic weather regimes in the last Millennium

NASA Astrophysics Data System (ADS)

Alvarez Castro, Maria del Carmen; Trasancos, Romain; Yiou, Pascal

2015-04-01

The European summer heatwaves have been increasing in frequency and magnitude in the past decades. A higher confidence in future changes in such extremes necessitates to have a better knowledge about extremes behavior in the past climate. The last millennium is well documented in terms of climate forcings. Modelling efforts have provided a wealth of climate simulations covering the last millennium. We want to exploit such data in order to assess how models simulate extreme summer heatwaves. The surface temperature and precipitation are closely related to atmospheric patterns. It has been shown that rainy winter/spring seasons reduce the frequency of hot summer days whereas dry seasons can be followed by summers with high or low frequency of hot days. In this poster, we show the relation between winter/spring precipitation with the frequency of hot days in the 10 hottest summers in Europe and Southern Europe during the Medieval Warm Period (MWP 1150-1250), the Little Ice Age (LIA 1650-1750), and the historical-present period (1850-2005). We first focus on a millennium simulations with the IPSL model (IPSL-CM5). We use daily temperature, precipitation, and SLP data from CMIP5 (Coupled Model Intercomparison Project phase 5) and a couple of IPSL simulations with diferents forcings. Summer weather regimes has been computed as well for NCEP sea level pressure data in order to compare observations with the same period (1948-2005) in CMIP5 and IPSL simulations outputs. We discuss and present the results comparing the effects of hydrological deficits in the preceding season, and the occurrence of specific weather regimes, during the hottest summers over Europe and SouthWestern Europe. This analysis compares differents climate forcings simulations.

Fully determined scaling laws for volumetrically heated convective systems, a tool for assessing habitability of exoplanets

NASA Astrophysics Data System (ADS)

Vilella, Kenny; Kaminski, Edouard

2017-05-01

The long-term habitability of a planet rises from its ability to generate and maintain an atmosphere through partial melting and volcanism. This question has been mainly addressed in the framework of plate tectonics, which may be too specific to apply to the wide range of internal dynamics expected for exoplanets, and even to the thermal evolution of the early Earth. Here we propose a more general theoretical approach of convection to build a regime diagram giving the conditions for partial melting to occur, in planetary bodies, as a function of key parameters that can be estimated for exoplanets, their size and internal heating rate. To that aim, we introduce a refined view of the Thermal Boundary Layer (TBL) in a convective system heated from within, that focuses on the temperature and thickness of the TBL at the top of the hottest temperature profiles, along which partial melting shall first occur. This ;Hottest Thermal Boundary Layer; (HotTBL) is first characterized using fully theoretical scaling laws based on the dynamics of thermal boundary layers. These laws are the first ones proposed in the literature that do not rely on empirical determinations of dimensionless constants and that apply to both low Rayleigh and high Rayleigh convective regimes. We show that the scaling laws can be successfully applied to planetary bodies by comparing their predictions to full numerical simulations of the Moon. We then use the scaling laws to build a regime diagram for exoplanets. Combined with estimates of internal heating in exoplanets, the regime diagram predicts that in the habitable zone partial melting occurs in planets younger than the Earth.

Fully Determined Scaling Laws for Volumetrically Heated Convective Systems, a Tool for Assessing Habitability of Exoplanets.

NASA Astrophysics Data System (ADS)

Vilella, K.; Kaminski, E. C.

2016-12-01

The long-term habitability of a planet rises from its ability to generate and maintain an atmosphere through partial melting and volcanism. This question has been mainly addressed in the framework of plate tectonics, which may be too specific to apply to the wide range of internal dynamics expected for exoplanets, and even to the thermal evolution of the early Earth. Here we propose a more general theoretical approach of convection to build a regime diagram giving the conditions for partial melting to occur in planetary bodies, as a function of key parameters that can be estimated for exoplanets, their size and internal heating rate. To that aim, we introduce a refined view of the Thermal Boundary layer (TBL) in a convective system heated from within, that focuses on the temperature and thickness of the TBL at the top of the hottest temperature profiles, along which partial melting shall first occur. This "Hottest Thermal Boundary Layer" (HotTBL) is first characterized using fully theoretical scaling laws based on the dynamics of thermal boundary layers. These laws are the first ones proposed in the literature that do not rely on empirical determinations of dimensionless constants and that apply to both low Rayleigh and high Rayleigh convective regimes. We show that the scaling laws can be successfully applied to planetary bodies by comparing their predictions to full numerical simulations of the Moon. We then use the scaling laws to build a regime diagram for exoplanets. Combined with estimates of internal heating in exoplanets, the regime diagram predicts that in the habitable zone partial melting occurs in planets younger than the Earth.

Fan cooling of the resting area in a free stalls dairy barn

NASA Astrophysics Data System (ADS)

Calegari, Ferdinando; Calamari, Luigi; Frazzi, Ermes

2014-08-01

This summer study evaluated the effect of providing additional fans (cooling) in the resting area within a free-stall dairy barn that had fans and sprinklers in the feeding area and paddock availability. Thirty cows were divided into two homogenous groups and kept in two pens: one had the resting area equipped with two fans (FAN) while no fans were added to the other resting area (CON). Microclimatic parameters, rectal temperature (RT), breathing rate (BR), milk yield, and milk pH traits were recorded. Time budgeting and the behaviour of the cows (time spent in the feeding area, standing and lying in other areas) were also recorded using digital video technology. Two slight-to-moderate heat waves were observed. During the hottest period the daily maximum temperature recorded was 33.5 °C and the daily maximum THI was 81.6. During this period, the BR and RT increased only slightly in both groups, with lower BR (n.s.) in FAN compared with CON. Milk yield was better maintained (n.s.) in FAN compared with CON during the hottest period. The FAN cows showed a greater ( P < 0.05) lying time in the free stalls (9.5 and 8.6 h/day in FAN and CON, respectively), whereas CON cows made greater ( P < 0.05) use of the paddock during evening and late evening hours. Consequently, the total daily lying time was 13.5 h/day in both groups. In conclusion, the results suggest that using fans in the resting area improves cow comfort, which increases use of the resting area. The lying time results also suggest that the benefits of providing ventilation in the resting area might be more evident in barns where there is no paddock.

Dust near luminous ultraviolet stars

NASA Technical Reports Server (NTRS)

Henry, Richard C.

1993-01-01

This report describes research activities related to the Infrared Astronomical Satellite (IRAS) sky survey. About 745 luminous stars were examined for the presence of interstellar dust heated by a nearby star. The 'cirrus' discovered by IRAS is thermal radiation from interstellar dust at moderate and high galactic latitudes. The IRAS locates the dust which must (at some level) scatter ultraviolet starlight, although it was expected that thermal emission would be found around virtually every star, most stars shown no detectable emission. And the emission found is not uniform. It is not that the star is embedded in 'an interstellar medium', but rather what is found are discrete clouds that are heated by starlight. An exception is the dearth of clouds near the very hottest stars, implying that the very hottest stars play an active role with respect to destroying or substantially modifying the dust clouds over time. The other possibility is simply that the hottest stars are located in regions lacking in dust, which is counter-intuitive. A bibliography of related journal articles is attached.

Study of the post-flare loops on 29 July 1973. II - Physical parameters in the X-ray loops

NASA Technical Reports Server (NTRS)

Petrasso, R. D.; Nolte, J. T.; Gerassimenko, M.; Krieger, A. S.; Krogstad, R.; Seguin, F. H.; Svestka, Z.

1979-01-01

We use the filter ratio method of analysis to determine spatially resolved values of plasma parameters in the X-ray emitting post-flare loop system which developed on 29 and 30 July 1973. We find that the loops were hotter and had higher plasma pressure at their tops than near their footpoints. The loop tops were at nearly the same temperature at different places 3 hr after the flare maximum and were also at nearly this same temperature 3 and 8 hr later. Variations in brightness transverse to the loops were due to variations in emission measure. We show by consideration of radiative losses alone that energy must have been added to the hottest part of the flare, at the tops of the loops, late in the decay phase of the flare.

Hottest Hot Jupiter Animation (Artist's Concept)

NASA Image and Video Library

2017-06-05

This artist's concept shows planet KELT-9b orbiting its host star, KELT-9. It is the hottest gas giant planet discovered so far. With a dayside temperature of more than 7,800 degrees Fahrenheit (4,600 Kelvin), KELT-9b is a planet that is hotter than most stars. But its star, called KELT-9, is even hotter -- a blue A-type star that is likely unraveling the planet through evaporation. KELT-9b is a gas giant 2.8 times more massive than Jupiter, but only half as dense. Scientists would expect the planet to have a smaller radius, but the extreme radiation from its host star has caused the planet's atmosphere to puff up like a balloon. The planet is also unusual in that it orbits perpendicular to the spin axis of the star. That would be analogous to the planet orbiting perpendicular to the plane of our solar system. One "year" on this planet is less than two days long. The KELT-9 star is only 300 million years old, which is young in star time. It is more than twice as large, and nearly twice as hot, as our sun. Given that the planet's atmosphere is constantly blasted with high levels of ultraviolet radiation, the planet may even be shedding a tail of evaporated planetary material like a comet. An animation is available at https://photojournal.jpl.nasa.gov/catalog/PIA21472

Airflow attenuation and bed net utilization: observations from Africa and Asia.

PubMed

von Seidlein, Lorenz; Ikonomidis, Konstantin; Bruun, Rasmus; Jawara, Musa; Pinder, Margaret; Knols, Bart Gj; Knudsen, Jakob B

2012-06-15

Qualitative studies suggest that bed nets affect the thermal comfort of users. To understand and reduce this discomfort the effect of bed nets on temperature, humidity, and airflow was measured in rural homes in Asia and Africa, as well as in an experimental wind tunnel. Two investigators with architectural training selected 60 houses in The Gambia, Tanzania, Philippines, and Thailand. Data-loggers were used to measure indoor temperatures in hourly intervals over a 12 months period. In a subgroup of 20 houses airflow, temperature and humidity were measured at five-minute intervals for one night from 21.00 to 6.00 hrs inside and outside of bed nets using sensors and omni-directional thermo-anemometers. An investigator set up a bed net with a mesh size of 220 holes per inch 2 in each study household and slept under the bed net to simulate a realistic environment. The attenuation of airflow caused by bed nets of different mesh sizes was also measured in an experimental wind tunnel. The highest indoor temperatures (49.0 C) were measured in The Gambia. During the hottest months of the year the mean temperature at night (9 pm) was between 33.1 C (The Gambia) and 26.2 C (Thailand). The bed net attenuated the airflow from a minimum of 27% (Philippines) to a maximum of 71% (The Gambia). Overall the bed nets reduced airflow compared to un-attenuated airflow from 9 to 4 cm sec-1 or 52% (p<0.001). In all sites, no statistically significant difference in temperature or humidity was detected between the inside and outside of the bed net. Wind tunnel experiments with 11 different mesh-sized bed nets showed an overall reduction in airflow of 64% (range 55 - 71%) compared to un-attenuated airflow. As expected, airflow decreased with increasing net mesh size. Nets with a mesh of 136 holes inch-2 reduced airflow by 55% (mean; range 51 - 73%). A denser net (200 holes inch-2) attenuated airflow by 59% (mean; range 56 - 74%). Despite concerted efforts to increase the uptake of this intervention in many areas uptake remains poor. Bed nets reduce airflow, but have no influence on temperature and humidity. The discomfort associated with bed nets is likely to be most intolerable during the hottest and most humid period of the year, which frequently coincides with the peak of malaria vector densities and the force of pathogen transmission. These observations suggest thermal discomfort is a factor limiting bed net use and open a range of architectural possibilities to overcome this limitation.

Microbial Communities and Chemosynthesis in Yellowstone Lake Sublacustrine Hydrothermal Vent Waters

PubMed Central

Yang, Tingting; Lyons, Shawn; Aguilar, Carmen; Cuhel, Russell; Teske, Andreas

2011-01-01

Five sublacustrine thermal spring locations from 1 to 109 m water depth in Yellowstone Lake were surveyed by 16S ribosomal RNA gene sequencing in relation to their chemical composition and dark CO2 fixation rates. They harbor distinct chemosynthetic bacterial communities, depending on temperature (16–110°C) and electron donor supply (H2S <1 to >100 μM; NH3 <0.5 to >10 μM). Members of the Aquificales, most closely affiliated with the genus Sulfurihydrogenibium, are the most frequently recovered bacterial 16S rRNA gene phylotypes in the hottest samples; the detection of these thermophilic sulfur-oxidizing autotrophs coincided with maximal dark CO2 fixation rates reaching near 9 μM C h−1 at temperatures of 50–60°C. Vents at lower temperatures yielded mostly phylotypes related to the mesophilic gammaproteobacterial sulfur oxidizer Thiovirga. In contrast, cool vent water with low chemosynthetic activity yielded predominantly phylotypes related to freshwater Actinobacterial clusters with a cosmopolitan distribution. PMID:21716640

Assessment of Urban Infrastructure Impact on New York City Neighborhoods Thermal Variations

NASA Astrophysics Data System (ADS)

Nazari, R.; Ghandehari, M.; Karimi, M.; Vant-hull, B.; Khanbilvardi, R.

2013-12-01

New York City (NYC) is a highly urbanized city with most of the population living in tall buildings. Despite technological improvements and stricter regulations, cities still show increasing signs of environmental stress such as traffic congestion, noise and air quality degradation. Rethinking the current models of city planning could enable to limit these detrimental effects of urbanization. In addition, the built environment creates a new climatic regime which needs a better understanding. Building density, height and emission has a major impact on local temperature and other air quality indicators. Studies have shown that during extreme weather conditions and heat waves the mortality rate in urban areas increases. Cities are comprised of a wide variety of urban settings and various neighborhoods have different physical responses to meteorological events, so it is expected that the temperature and heat stress across a given city to fluctuate sharply. Therefore, this research has focused on neighborhood-scale field campaigns to downscale temperature and air quality predictions from city to neighborhood scale in NYC. In order to assess the temperature variability within the city at street level, during the hottest part of the day, this project used eight mobile units bearing temperature and relative humidity sensors, as well as ten weather stations mounted on light poles in various NYC neighborhoods. This study also looks at fine scale structures in the urban heat island of Manhattan at street level through an infrared camera with the spectral range of 7.5-13 μm in order to relate heat and emissions from building surfaces to land surface characteristics such as building density, vegetation coverage, proximity to water, and albedo. LandSat TM5 images were used (with 30 m resolution) for land surface classification. During the summer and early fall of 2011, 2012 and 2013 extensive field campaigns were performed, the results of which show some persistent patterns that could be related to surface characteristics. This work is a collaboration between the health component of the Consortium for Climate Risk in the Urban Northeast (CCRUN), funded by NOAA Regional Integrated Science Assessment (RISA), and New York University Center for Urban Science and Progress (CUSP).

A heat vulnerability index to improve urban public health management in San Juan, Puerto Rico.

PubMed

Méndez-Lázaro, Pablo; Muller-Karger, Frank E; Otis, Daniel; McCarthy, Matthew J; Rodríguez, Ernesto

2018-05-01

Increased frequency and length of high heat episodes are leading to more cardiovascular issues and asthmatic responses among the population of San Juan, the capital of the island of Puerto Rico, USA. An urban heat island effect, which leads to foci of higher temperatures in some urban areas, can raise heat-related mortality. The objective of this research is to map the risk of high temperature in particular locations by creating heat maps of the city of San Juan. The heat vulnerability index (HVI) maps were developed using images collected by satellite-based remote sensing combined with census data. Land surface temperature was assessed using images from the Thermal Infrared Sensor flown on Landsat 8. Social determinants (e.g., age, unemployment, education and social isolation, and health insurance coverage) were analyzed by census tract. The data were examined in the context of land cover maps generated using products from the Puerto Rico Terrestrial Gap Analysis Project (USDA Forest Service). All variables were set in order to transform the indicators expressed in different units into indices between 0 and 1, and the HVI was calculated as sum of score. The tract with highest index was considered to be the most vulnerable and the lowest to be the least vulnerable. Five vulnerability classes were mapped (very high, high, moderate, low, and very low). The hottest and the most vulnerable tracts corresponded to highly built areas, including the Luis Munoz International Airport, seaports, parking lots, and high-density residential areas. Several variables contributed to increased vulnerability, including higher rates of the population living alone, disabilities, advanced age, and lack of health insurance coverage. Coolest areas corresponded to vegetated landscapes and urban water bodies. The urban HVI map will be useful to health officers, emergency preparedness personnel, the National Weather Service, and San Juan residents, as it helps to prepare for and to mitigate the potential effects of heat-related illnesses.

A heat vulnerability index to improve urban public health management in San Juan, Puerto Rico

NASA Astrophysics Data System (ADS)

Méndez-Lázaro, Pablo; Muller-Karger, Frank E.; Otis, Daniel; McCarthy, Matthew J.; Rodríguez, Ernesto

2018-05-01

Increased frequency and length of high heat episodes are leading to more cardiovascular issues and asthmatic responses among the population of San Juan, the capital of the island of Puerto Rico, USA. An urban heat island effect, which leads to foci of higher temperatures in some urban areas, can raise heat-related mortality. The objective of this research is to map the risk of high temperature in particular locations by creating heat maps of the city of San Juan. The heat vulnerability index (HVI) maps were developed using images collected by satellite-based remote sensing combined with census data. Land surface temperature was assessed using images from the Thermal Infrared Sensor flown on Landsat 8. Social determinants (e.g., age, unemployment, education and social isolation, and health insurance coverage) were analyzed by census tract. The data were examined in the context of land cover maps generated using products from the Puerto Rico Terrestrial Gap Analysis Project (USDA Forest Service). All variables were set in order to transform the indicators expressed in different units into indices between 0 and 1, and the HVI was calculated as sum of score. The tract with highest index was considered to be the most vulnerable and the lowest to be the least vulnerable. Five vulnerability classes were mapped (very high, high, moderate, low, and very low). The hottest and the most vulnerable tracts corresponded to highly built areas, including the Luis Munoz International Airport, seaports, parking lots, and high-density residential areas. Several variables contributed to increased vulnerability, including higher rates of the population living alone, disabilities, advanced age, and lack of health insurance coverage. Coolest areas corresponded to vegetated landscapes and urban water bodies. The urban HVI map will be useful to health officers, emergency preparedness personnel, the National Weather Service, and San Juan residents, as it helps to prepare for and to mitigate the potential effects of heat-related illnesses.

A heat vulnerability index to improve urban public health management in San Juan, Puerto Rico

NASA Astrophysics Data System (ADS)

Méndez-Lázaro, Pablo; Muller-Karger, Frank E.; Otis, Daniel; McCarthy, Matthew J.; Rodríguez, Ernesto

2017-02-01

Increased frequency and length of high heat episodes are leading to more cardiovascular issues and asthmatic responses among the population of San Juan, the capital of the island of Puerto Rico, USA. An urban heat island effect, which leads to foci of higher temperatures in some urban areas, can raise heat-related mortality. The objective of this research is to map the risk of high temperature in particular locations by creating heat maps of the city of San Juan. The heat vulnerability index (HVI) maps were developed using images collected by satellite-based remote sensing combined with census data. Land surface temperature was assessed using images from the Thermal Infrared Sensor flown on Landsat 8. Social determinants (e.g., age, unemployment, education and social isolation, and health insurance coverage) were analyzed by census tract. The data were examined in the context of land cover maps generated using products from the Puerto Rico Terrestrial Gap Analysis Project (USDA Forest Service). All variables were set in order to transform the indicators expressed in different units into indices between 0 and 1, and the HVI was calculated as sum of score. The tract with highest index was considered to be the most vulnerable and the lowest to be the least vulnerable. Five vulnerability classes were mapped (very high, high, moderate, low, and very low). The hottest and the most vulnerable tracts corresponded to highly built areas, including the Luis Munoz International Airport, seaports, parking lots, and high-density residential areas. Several variables contributed to increased vulnerability, including higher rates of the population living alone, disabilities, advanced age, and lack of health insurance coverage. Coolest areas corresponded to vegetated landscapes and urban water bodies. The urban HVI map will be useful to health officers, emergency preparedness personnel, the National Weather Service, and San Juan residents, as it helps to prepare for and to mitigate the potential effects of heat-related illnesses.

Correlation between asthma and climate in the European Community Respiratory Health Survey.

PubMed

Verlato, Giuseppe; Calabrese, Rolando; De Marco, Roberto

2002-01-01

The European Community Respiratory Health Survey, performed during 1991-1993, found a remarkable geographical variability in the prevalence of asthma and asthma-like symptoms in individuals aged 20-44 yr. The highest values occurred in the English-speaking centers. In the present investigation, the ecological relationship between climate and symptom prevalence was evaluated in the 48 centers of the European Community Respiratory Health Survey. Meteorological variables were derived from the Global Historical Climatology Network and were averaged over an 11-yr period (i.e., 1980-1990). Respiratory symptom prevalence was directly related to temperature in the coldest month and was related inversely to the temperature in the hottest month. Warm winters and cool summers are features of oceanic climate found in most English-speaking centers of the European Community Respiratory Health Survey (i.e., England, New Zealand, and Oregon). In conclusion, climate can account for significant geographic variability in respiratory symptom prevalence.

Effective temperatures and luminosities of very hot o-type subdwarfs

NASA Technical Reports Server (NTRS)

Schoenberner, D.; Drilling, J. S.

1982-01-01

Twelve very hot O-type subdwarfs were observed with the IUE-satellite in the low dispersion mode. Temperatures were derived from the slopes of the UV continua and distances were estimated from the color excesses. Most of them are hotter than 60,000 K, i.e., they are the hottest known subdwarfs. From their spectral appearance and location in a H.R.-diagram they form a rather inhomogeneous group. Three of them turned out to be central stars or nearly central stars, and four are definitely near the white dwarf stage. The surface helium to hydrogen ratio varies from about normal to the extreme case. Most of them appear to be post EHB objectives of 0.5 solar mass with a helium burning shell as their energy source, and their peculiar helium-to-hydrogen ratios are most likely the result of diffusion and convective mixing in surface layers.

NASA Spacecraft Watches as Eruption Reshapes African Volcano

NASA Image and Video Library

2017-02-23

On Jan. 24, 2017, the Hyperion Imager on NASA's Earth Observing 1 (EO-1) spacecraft observed a new eruption at Erta'Ale volcano, Ethiopia, from an altitude of 438 miles (705 kilometers). Data were collected at a resolution of 98 feet (30 meters) per pixel at different visible and infrared wavelengths and were combined to create these images. A visible-wavelength image is on the left. An infrared image is shown on the right. The infrared image emphasizes the hottest areas and reveals a spectacular rift eruption, where a crack opens and lava gushes forth, fountaining into the air. The lava flows spread away from the crack. Erta'Ale is the location of a long-lived lava lake, and it remains to be seen if this survives this new eruption. The observation was scheduled via the Volcano Sensor Web, a network of sensors linked by artificial intelligence software to create an autonomous global monitoring program of satellite observations of volcanoes. The Volcano Sensor Web was alerted to this new activity by data from another spacecraft. http://photojournal.jpl.nasa.gov/catalog/PIA11239

From Hot to Hottest

NASA Image and Video Library

2017-10-31

This sequence of images shows the sun from its surface to its upper atmosphere all taken at about the same time (Oct. 27, 2017). The first shows the surface of the sun in filtered white light; the other seven images were taken in different wavelengths of extreme ultraviolet light. Note that each wavelength reveals somewhat different features. They are shown in order of temperature from the first one at 6,000 degree C. surface out to about 10 million degrees C. in the upper atmosphere. Yes, the sun's outer atmosphere is much, much hotter than the surface. Scientists are getting closer to solving the processes that generate this phenomenon. https://photojournal.jpl.nasa.gov/catalog/PIA22055

Dust discs around low-mass main-sequence stars

NASA Technical Reports Server (NTRS)

Wolstencroft, R. D.; Walker, Helen J.

1988-01-01

The current understanding of the formation of circumstellar disks as a natural accompaniment to the process of low-mass star formation is examined. Models of the thermal emission from the dust disks around the prototype stars Alpha Lyr, Alpha PsA, Beta Pic, and Epsilon Eri are discussed, which indicate that the central regions of three of these disks are almost devoid of dust within radii ranging between 17 and 26 AU, with the temperature of the hottest zone lying between about 115 and 210 K. One possible explanation of the dust-free zones is the presence of a planet at the inner boundary of each cloud which sweeps up grains crossing its orbit.

The European 2015 drought from a climatological perspective

NASA Astrophysics Data System (ADS)

Ionita, Monica; Tallaksen, Lena M.; Kingston, Daniel G.; Stagge, James H.; Laaha, Gregor; Van Lanen, Henny A. J.; Scholz, Patrick; Chelcea, Silvia M.; Haslinger, Klaus

2017-03-01

The summer drought of 2015 affected a large portion of continental Europe and was one of the most severe droughts in the region since summer 2003. The summer of 2015 was characterized by exceptionally high temperatures in many parts of central and eastern Europe, with daily maximum temperatures 2 °C higher than the seasonal mean (1971-2000) over most of western Europe, and more than 3 °C higher in the east. It was the hottest and climatologically driest summer over the 1950-2015 study period for an area stretching from the eastern Czech Republic to Ukraine. For Europe, as a whole, it is among the six hottest and driest summers since 1950. High evapotranspiration rates combined with a lack of precipitation affected soil moisture and vegetation and led to record low river flows in several major rivers, even beyond the drought-hit region. The 2015 drought developed rather rapidly over the Iberian Peninsula, France, southern Benelux and central Germany in May and reached peak intensity and spatial extent by August, affecting especially the eastern part of Europe. Over the summer period, there were four heat wave episodes, all associated with persistent blocking events. Upper-level atmospheric circulation over Europe was characterized by positive 500 hPa geopotential height anomalies flanked by a large negative anomaly to the north and west (i.e., over the central North Atlantic Ocean extending to northern Fennoscandia) and another center of positive geopotential height anomalies over Greenland and northern Canada. Simultaneously, the summer sea surface temperatures (SSTs) were characterized by large negative anomalies in the central North Atlantic Ocean and large positive anomalies in the Mediterranean basin. Composite analysis shows that the western Mediterranean SST is strongly related to the occurrence of dry and hot summers over the last 66 years (especially over the eastern part of Europe). The lagged relationship between the Mediterranean SST and summer drought conditions established in this study can provide valuable skill for the prediction of drought conditions over Europe on interannual to decadal timescales.

Cooling of gas turbines IX : cooling effects from use of ceramic coatings on water-cooled turbine blades

NASA Technical Reports Server (NTRS)

Brown, W Byron; Livingood, John N B

1948-01-01

The hottest part of a turbine blade is likely to be the trailing portion. When the blades are cooled and when water is used as the coolant, the cooling passages are placed as close as possible to the trailing edge in order to cool this portion. In some cases, however, the trailing portion of the blade is so narrow, for aerodynamic reasons, that water passages cannot be located very near the trailing edge. Because ceramic coatings offer the possibility of protection for the trailing part of such narrow blades, a theoretical study has been made of the cooling effect of a ceramic coating on: (1) the blade-metal temperature when the gas temperature is unchanged, and (2) the gas temperature when the metal temperature is unchanged. Comparison is also made between the changes in the blade or gas temperatures produced by ceramic coatings and the changes produced by moving the cooling passages nearer the trailing edge. This comparison was made to provide a standard for evaluating the gains obtainable with ceramic coatings as compared to those obtainable by constructing the turbine blade in such a manner that water passages could be located very near the trailing edge.

Spatially resolved measurement of the core temperature in a high-power thulium fiber system

NASA Astrophysics Data System (ADS)

Walbaum, Till; Heinzig, Matthias; Beier, Franz; Liem, Andreas; Schreiber, Thomas; Eberhardt, Ramona; Tünnermann, Andreas

2016-03-01

We present measurements of the temperature increase inside the active fiber of a thulium fiber amplifier during high power operation. At a pump power of over 100 W at a wavelength of 793 nm, we measure the core temperature distribution along the first section of a large mode area (LMA) highly thulium doped active fiber by use of an optical backscatter reflectometer. A mode field adaptor is used to maintain single mode operation in the LMA fiber. An increase in temperature of over 100 K can be observed in spite of conductive cooling, located at the pumped fiber end and jeopardizing the fiber coating. The recoated splice can be clearly identified as the hottest fiber region. This allows us to estimate the maximum thermally acceptable pump power for this amplifier. We also observe that the temperature can be decreased by increasing the seed power, which is in agreement with theoretical predictions on the increase of cross relaxation efficiency by depletion of the upper laser level. This underlines the role of power scaling of the respective seed power of a thulium amplifier stage as a means of thermal management.

Thermal biology of Pacific cicada killers, Sphecius convallis Patton, in the Upper Sonoran Desert.

PubMed

Coelho, Joseph R; Holliday, Charles W; Hastings, Jon M; Phillips, Christy M

2016-04-01

A comprehensive investigation of the Pacific cicada killer, Sphecius convallis Patton, was undertaken to examine the behavioral and physiological mechanisms by which they are able to complete their life cycle in the thermal extremes of the Upper Sonoran Desert. S. convallis were endothermic, exhibiting elevated and relatively constant thorax temperatures during many activities. Males basked in trees at dawn to warm up, then used a variety of behaviors and perching strategies to maintain thorax temperature during territorial behavior. The thorax temperature of females was highest during provisioning and orientation flights, somewhat lower while investigating burrows, and lowest while digging burrows. The optimal thorax temperature for flight was about 40°C, which was approximated most closely by males resting in the shade during the afternoon. In mating clusters, the mated male was the hottest, the female was coolest and the other males were intermediate. Wasps lost about 5% of body mass during heating treatments, and may use evaporative water loss for cooling. Pacific cicada killers use a complex suite of behavioral and physiological adaptations to regulate body temperature during their nesting season. Copyright © 2016 Elsevier Ltd. All rights reserved.

Deepest and hottest hydrothermal activity in the Okinawa Trough: the Yokosuka site at Yaeyama Knoll

PubMed Central

Miyazaki, Junichi; Kawagucci, Shinsuke; Makabe, Akiko; Takahashi, Ayu; Kitada, Kazuya; Torimoto, Junji; Matsui, Yohei; Tasumi, Eiji; Shibuya, Takazo; Nakamura, Kentaro; Horai, Shunsuke; Sato, Shun; Ishibashi, Jun-ichiro; Kanzaki, Hayato; Nakagawa, Satoshi; Hirai, Miho; Takaki, Yoshihiro; Okino, Kyoko; Watanabe, Hiromi Kayama; Kumagai, Hidenori

2017-01-01

Since the initial discovery of hydrothermal vents in 1977, these ‘extreme’ chemosynthetic systems have been a focus of interdisciplinary research. The Okinawa Trough (OT), located in the semi-enclosed East China Sea between the Eurasian continent and the Ryukyu arc, hosts more than 20 known vent sites but all within a relatively narrow depth range (600–1880 m). Depth is a significant factor in determining fluid temperature and chemistry, as well as biological composition. However, due to the narrow depth range of known sites, the actual influence of depth here has been poorly resolved. Here, the Yokosuka site (2190 m), the first OT vent exceeding 2000 m depth is reported. A highly active hydrothermal vent site centred around four active vent chimneys reaching 364°C in temperature, it is the hottest in the OT. Notable Cl depletion (130 mM) and both high H2 and CH4 concentrations (approx. 10 mM) probably result from subcritical phase separation and thermal decomposition of sedimentary organic matter. Microbiota and fauna were generally similar to other sites in the OT, although with some different characteristics. In terms of microbiota, the H2-rich vent fluids in Neuschwanstein chimney resulted in the dominance of hydrogenotrophic chemolithoautotrophs such as Thioreductor and Desulfobacterium. For fauna, the dominance of the deep-sea mussel Bathymodiolus aduloides is surprising given other nearby vent sites are usually dominated by B. platifrons and/or B. japonicus, and a sponge field in the periphery dominated by Poecilosclerida is unusual for OT vents. Our insights from the Yokosuka site implies that although the distribution of animal species may be linked to depth, the constraint is perhaps not water pressure and resulting chemical properties of the vent fluid but instead physical properties of the surrounding seawater. The potential significance of these preliminary results and prospect for future research on this unique site are discussed. PMID:29308272

Deepest and hottest hydrothermal activity in the Okinawa Trough: the Yokosuka site at Yaeyama Knoll

NASA Astrophysics Data System (ADS)

Miyazaki, Junichi; Kawagucci, Shinsuke; Makabe, Akiko; Takahashi, Ayu; Kitada, Kazuya; Torimoto, Junji; Matsui, Yohei; Tasumi, Eiji; Shibuya, Takazo; Nakamura, Kentaro; Horai, Shunsuke; Sato, Shun; Ishibashi, Jun-ichiro; Kanzaki, Hayato; Nakagawa, Satoshi; Hirai, Miho; Takaki, Yoshihiro; Okino, Kyoko; Watanabe, Hiromi Kayama; Kumagai, Hidenori; Chen, Chong

2017-12-01

Since the initial discovery of hydrothermal vents in 1977, these `extreme' chemosynthetic systems have been a focus of interdisciplinary research. The Okinawa Trough (OT), located in the semi-enclosed East China Sea between the Eurasian continent and the Ryukyu arc, hosts more than 20 known vent sites but all within a relatively narrow depth range (600-1880 m). Depth is a significant factor in determining fluid temperature and chemistry, as well as biological composition. However, due to the narrow depth range of known sites, the actual influence of depth here has been poorly resolved. Here, the Yokosuka site (2190 m), the first OT vent exceeding 2000 m depth is reported. A highly active hydrothermal vent site centred around four active vent chimneys reaching 364°C in temperature, it is the hottest in the OT. Notable Cl depletion (130 mM) and both high H2 and CH4 concentrations (approx. 10 mM) probably result from subcritical phase separation and thermal decomposition of sedimentary organic matter. Microbiota and fauna were generally similar to other sites in the OT, although with some different characteristics. In terms of microbiota, the H2-rich vent fluids in Neuschwanstein chimney resulted in the dominance of hydrogenotrophic chemolithoautotrophs such as Thioreductor and Desulfobacterium. For fauna, the dominance of the deep-sea mussel Bathymodiolus aduloides is surprising given other nearby vent sites are usually dominated by B. platifrons and/or B. japonicus, and a sponge field in the periphery dominated by Poecilosclerida is unusual for OT vents. Our insights from the Yokosuka site implies that although the distribution of animal species may be linked to depth, the constraint is perhaps not water pressure and resulting chemical properties of the vent fluid but instead physical properties of the surrounding seawater. The potential significance of these preliminary results and prospect for future research on this unique site are discussed.

A nonintrusive method for measuring the operating temperature of a solenoid-operated valve

NASA Astrophysics Data System (ADS)

Kryter, Robert C.

Experimental data are presented to show that the in-service operating temperature of a solenoid operated valve (SOV) can be inferred simply and nondisruptively by using the copper winding of the solenoid coil as a self-indicating, permanently available resistance thermometer. The principal merits of this approach include: (1) there is no need for an add-on temperature sensor, (2) the true temperature of a critical and likely the hottest, part of the SOV (namely, the electrical coil) is measured directly, (3) temperature readout can be provided at any location at which the SOV electrical lead wires are accessible (even though remote from the valve), (4) the SOV need not be disturbed (whether normally energized or deenergized) to measure its temperature in situ, and (5) the method is applicable to all types of SOVs, large and small, ac- and dc-powered. Laboratory tests comparing temperatures measured both by coil resistance and by a conventional thermometer placed in contact with the external surface of the potted solenoid coil indicate that temperature within the coil may be on the order of 40 C higher than that measured externally, a fact that is important to life-expectancy calculations made on the basis of Arrhenius theory. Field practicality is illustrated with temperature measurements made using this method on a SOV controlling the flow of refrigerant in a large chilled-water air-conditioning system.

Observed ozone exceedances in Italy: statistical analysis and modelling in the period 2002-2015

NASA Astrophysics Data System (ADS)

Falasca, Serena; Curci, Gabriele; Candeloro, Luca; Conte, Annamaria; Ippoliti, Carla

2017-04-01

Local ambient air quality is strongly influenced by anthropogenic emissions and meteorological conditions. The year 2015 is considered by NASA scientists as one of the hottest at the global scale since 1880. Furthermore, in Europe it was the first summer after the introduction of Euro6 regulation, the latest emission standard for passenger vehicles. The goal of this study is twofold: (1) the investigation of the impact of the heat wave occurred in the summer of 2015 on ozone levels and (2) the exploration of the weight of temperature as driver of high-level ozone events with respect to other variables. We performed a quantitative examination of the ozone seasons (May-September) for the period 2002-2015 using ozone concentration and weather data from 24 stations across Italy. The number of exceedances of limit values set by the European directive was calculated for each year, and compared with the trend of ozone concentration and temperature. Furthermore, the data were grouped in clusters of consecutive days of ozone exceedances in order to characterize the duration and the intensity of high ozone events. Finally, we developed a multivariate logistic regression model to investigate the role of a set of independent variables (meteorological, and temporal variables, altitude, number of inhabitants, vehicle emission standard) on the probability of exceedances. Results show that 2015 is one of the hottest years after 2003. During the period 2002-2015, the average number of exceedances per station of the daily maximum 8-hour average is often higher than the limit established by the European directive (25 per year). The highest number of exceedances was 65 per station, reached in 2003. The Po Valley is confirmed as a hot spot for pollution, with more frequent exceedances and a higher sensitivity to temperature, especially at urban sites. Ozone events in 2015 were fewer than recent years, but of longer duration (on average 4 days against 3 days), and with similar mean concentrations. On the other hand, high-temperature events have similar duration and higher mean temperature with respect to recent years, pointing out that temperature is not the only driver of high-ozone events. The statistical model confirms a significant impact of the meteorological variables (positive for temperature and pressure, negative for humidity and wind speed) on the probability of ozone events. Significant predictors are also the altitude (negative) and the number of inhabitants (positive). The decreasing observed recent trend is explained by the introduction of the Euro regulations, rather than natural variability. However, we find an inversion of trend for the more recent period under Euro6 (from September 2014), but we cautionary wait a confirmation from additional data at least for the year 2016.

Untangling the roles of microclimate, behaviour and physiological polymorphism in governing vulnerability of intertidal snails to heat stress.

PubMed

Dong, Yun-Wei; Li, Xiao-Xu; Choi, Francis M P; Williams, Gray A; Somero, George N; Helmuth, Brian

2017-05-17

Biogeographic distributions are driven by cumulative effects of smaller scale processes. Thus, vulnerability of animals to thermal stress is the result of physiological sensitivities to body temperature ( T b ), microclimatic conditions, and behavioural thermoregulation. To understand interactions among these variables, we analysed the thermal tolerances of three species of intertidal snails from different latitudes along the Chinese coast, and estimated potential T b in different microhabitats at each site. We then empirically determined the temperatures at which heart rate decreased sharply with rising temperature (Arrhenius breakpoint temperature, ABT) and at which it fell to zero (flat line temperature, FLT) to calculate thermal safety margins (TSM). Regular exceedance of FLT in sun-exposed microhabitats, a lethal effect, was predicted for only one mid-latitude site. However, ABTs of some individuals were exceeded at sun-exposed microhabitats in most sites, suggesting physiological impairment for snails with poor behavioural thermoregulation and revealing inter-individual variations (physiological polymorphism) of thermal limits. An autocorrelation analysis of T b showed that predictability of extreme temperatures was lowest at the hottest sites, indicating that the effectiveness of behavioural thermoregulation is potentially lowest at these sites. These results illustrate the critical roles of mechanistic studies at small spatial scales when predicting effects of climate change. © 2017 The Author(s).

Untangling the roles of microclimate, behaviour and physiological polymorphism in governing vulnerability of intertidal snails to heat stress

PubMed Central

Li, Xiao-xu; Choi, Francis M. P.; Williams, Gray A.; Somero, George N.; Helmuth, Brian

2017-01-01

Biogeographic distributions are driven by cumulative effects of smaller scale processes. Thus, vulnerability of animals to thermal stress is the result of physiological sensitivities to body temperature (Tb), microclimatic conditions, and behavioural thermoregulation. To understand interactions among these variables, we analysed the thermal tolerances of three species of intertidal snails from different latitudes along the Chinese coast, and estimated potential Tb in different microhabitats at each site. We then empirically determined the temperatures at which heart rate decreased sharply with rising temperature (Arrhenius breakpoint temperature, ABT) and at which it fell to zero (flat line temperature, FLT) to calculate thermal safety margins (TSM). Regular exceedance of FLT in sun-exposed microhabitats, a lethal effect, was predicted for only one mid-latitude site. However, ABTs of some individuals were exceeded at sun-exposed microhabitats in most sites, suggesting physiological impairment for snails with poor behavioural thermoregulation and revealing inter-individual variations (physiological polymorphism) of thermal limits. An autocorrelation analysis of Tb showed that predictability of extreme temperatures was lowest at the hottest sites, indicating that the effectiveness of behavioural thermoregulation is potentially lowest at these sites. These results illustrate the critical roles of mechanistic studies at small spatial scales when predicting effects of climate change. PMID:28469014

Far-UV Spectroscopy of Two Extremely Hot, Helium-Rich White Dwarfs

NASA Technical Reports Server (NTRS)

Werner, K.; Rauch, T.; Kruk, J. W.

2017-01-01

A large proportion of hot post-asymptotic giant branch stars and white dwarfs (WDs) are hydrogen-deficient. Two distinct evolutionary sequences have been identified. One of them comprises stars of spectral type [WC] and PG1159, and it originates from a late helium-shell flash, creating helium-rich stellar atmospheres with significant admixtures of carbon (up to about 50, mass fraction). The other sequence comprises stars of spectral type O(He) and luminous subdwarf O stars which possibly are descendants of RCrB stars and extreme helium stars. Their carbon abundances are significantly lower (of the order of 1 or less) and it is thought that they originate from binary-star evolution (through merger or common-envelope evolution). Here we investigate two of the three hottest known helium-rich (DO) WDs (PG 1034+001 and PG 0038+199). They are the only ones for which spectra were recorded with the Far Ultraviolet Spectroscopic Explorer and the Hubble Space Telescope, allowing a comprehensive ultraviolet spectral analysis. We find effective temperatures of T(eff) =115000 +/- 5000 K and 125000 +/- 5000 K, respectively, and a surface gravity of log g = 7 +/-0.5. In both stars, nitrogen is strongly oversolar while C and O are significantly subsolar. For all other assessed metals (Ne, Si, P, S, Ar, Fe, and Ni) we find abundances close to solar. We conclude that these WDs are immediate descendants of O(He) stars and, hence, result from close-binary evolution.

Nanocarbon materials fabricated using plasmas

NASA Astrophysics Data System (ADS)

Hatakeyama, Rikizo

2017-12-01

Since the discovery of fullerenes more than three decades ago, new kinds of nanoscale materials of carbon allotropes called "nanocarbons" have so far been discovered or synthesized at successive intervals as cases such as carbon nanotubes, carbon nanohorns, graphene, carbon nanowalls, and a carbon nanobelt, while nanodiamonds were actually discovered before then. Their attractively excellent mechanical, physical, and chemical properties have driven researchers to continuously create one of the hottest frontiers in materials science and technology. While plasma states have often been involved in their discovery, on the other hand, plasma-based approaches to this exciting field originally hold promising and enormous potentials for advancing and expanding industrial/biomedical applications of nanocarbons of great diversity. This article provides an extensive overview on plasma-fabricated nanocarbon materials, where the term "fabrication" is defined as synthesis, functionalization, and assembly of devices to cover a wide range of issues associated with the step-by-step plasma processes. Specific attention has been paid to the comparative examination between plasma-based and non-plasma methods for fabricating the nanocarobons with an emphasis on the advantages of plasma processing, such as low-temperature/large-scale fabrication and diversity-carrying structure controllability. The review ends with current challenges and prospects including a ripple effect of the nanocarbon studies on the development of related novel nanomaterials such as transition metal dichalcogenides. It contains not only the latest progress in the field for cutting-edge scientists and engineers, but also the introductory guidance to non-specialists such as lower-class graduate students.

Nanodiamond for hydrogen storage: temperature-dependent hydrogenation and charge-induced dehydrogenation.

PubMed

Lai, Lin; Barnard, Amanda S

2012-02-21

Carbon-based hydrogen storage materials are one of hottest research topics in materials science. Although the majority of studies focus on highly porous loosely bound systems, these systems have various limitations including use at elevated temperature. Here we propose, based on computer simulations, that diamond nanoparticles may provide a new promising high temperature candidate with a moderate storage capacity, but good potential for recyclability. The hydrogenation of nanodiamonds is found to be easily achieved, in agreement with experiments, though we find the stability of hydrogenation is dependent on the morphology of nanodiamonds and surrounding environment. Hydrogenation is thermodynamically favourable even at high temperature in pure hydrogen, ammonia, and methane gas reservoirs, whereas water vapour can help to reduce the energy barrier for desorption. The greatest challenge in using this material is the breaking of the strong covalent C-H bonds, and we have identified that the spontaneous release of atomic hydrogen may be achieved through charging of hydrogenated nanodiamonds. If the degree of induced charge is properly controlled, the integrity of the host nanodiamond is maintained, which indicates that an efficient and recyclable approach for hydrogen release may be possible. This journal is © The Royal Society of Chemistry 2012

Cubic zirconia in >2370 °C impact melt records Earth's hottest crust

NASA Astrophysics Data System (ADS)

Timms, Nicholas E.; Erickson, Timmons M.; Zanetti, Michael R.; Pearce, Mark A.; Cayron, Cyril; Cavosie, Aaron J.; Reddy, Steven M.; Wittmann, Axel; Carpenter, Paul K.

2017-11-01

Bolide impacts influence primordial evolution of planetary bodies because they can cause instantaneous melting and vaporization of both crust and impactors. Temperatures reached by impact-generated silicate melts are unknown because meteorite impacts are ephemeral, and established mineral and rock thermometers have limited temperature ranges. Consequently, impact melt temperatures in global bombardment models of the early Earth and Moon are poorly constrained, and may not accurately predict the survival, stabilization, geochemical evolution and cooling of early crustal materials. Here we show geological evidence for the transformation of zircon to cubic zirconia plus silica in impact melt from the 28 km diameter Mistastin Lake crater, Canada, which requires super-heating in excess of 2370 °C. This new temperature determination is the highest recorded from any crustal rock. Our phase heritage approach extends the thermometry range for impact melts by several hundred degrees, more closely bridging the gap between nature and theory. Profusion of >2370 °C superheated impact melt during high intensity bombardment of Hadean Earth likely facilitated consumption of early-formed crustal rocks and minerals, widespread volatilization of various species, including hydrates, and formation of dry, rigid, refractory crust.

Preliminary investigation of thermal behaviour of PCM based latent heat thermal energy storage

NASA Astrophysics Data System (ADS)

Pop, Octavian G.; Fechete Tutunaru, Lucian; Bode, Florin; Balan, Mugur C.

2018-02-01

Solid-liquid phase change is used to accumulate and release cold in latent heat thermal energy storage (LHTES) in order to reduce energy consumption of air cooling system in buildings. The storing capacity of the LHTES depends greatly on the exterior air temperatures during the summer nights. One approach in intensifying heat transfer is by increasing the air's velocity. A LHTES was designed to be integrated in the air cooling system of a building located in Bucharest, during the month of July. This study presents a numerical investigation concerning the impact of air inlet temperatures and air velocity on the formation of solid PCM, on the cold storing capacity and energy consumption of the LHTES. The peak amount of accumulated cold is reached at different air velocities depending on air inlet temperature. For inlet temperatures of 14°C and 15°C, an increase of air velocity above 50% will not lead to higher amounts of cold being stored. For Bucharest during the hottest night of the year, a 100 % increase in air velocity will result in 5.02% more cold being stored, at an increase in electrical energy consumption of 25.30%, when compared to the reference values.

Mechanism of non-appearance of hiatus in Tibetan Plateau.

PubMed

Ma, Jieru; Guan, Xiaodan; Guo, Ruixia; Gan, Zewen; Xie, Yongkun

2017-06-30

In the recent decade, hiatus is the hottest issue in the community of climate change. As the area of great importance, the Tibetan Plateau (TP), however, did not appear to have any warming stoppage in the hiatus period. In fact, the TP showed a continuous warming in the recent decade. To explore why the TP did not show hiatus, we divide the surface air temperature into dynamically-induced temperature (DIT) and radiatively-forced temperature (RFT) by applying the dynamical adjustment method. Our results show that DIT displayed a relatively uniform warming background in the TP, with no obvious correlations with dynamic factors. Meanwhile, as the major contribution to warming, the RFT effect over the TP played the dominant role. The warming role is illustrated using the temperature change between perturbed and control simulation responses to CO 2 or black carbon (BC) forcing via Community Earth System Model (CESM). It shows that an obvious warming in the TP is induced by the CO 2 warming effect, and BC exhibits an amplifying effect on the warming. Therefore, the continuous warming in the TP was a result of uniform DIT warming over a large scale and enhanced RFT warming at a regional scale.

Australia's Unprecedented Future Temperature Extremes Under Paris Limits to Warming

NASA Astrophysics Data System (ADS)

Lewis, Sophie C.; King, Andrew D.; Mitchell, Daniel M.

2017-10-01

Record-breaking temperatures can detrimentally impact ecosystems, infrastructure, and human health. Previous studies show that climate change has influenced some observed extremes, which are expected to become more frequent under enhanced future warming. Understanding the magnitude, as a well as frequency, of such future extremes is critical for limiting detrimental impacts. We focus on temperature changes in Australian regions, including over a major coral reef-building area, and assess the potential magnitude of future extreme temperatures under Paris Agreement global warming targets (1.5°C and 2°C). Under these limits to global mean warming, we determine a set of projected high-magnitude unprecedented Australian temperature extremes. These include extremes unexpected based on observational temperatures, including current record-breaking events. For example, while the difference in global-average warming during the hottest Australian summer and the 2°C Paris target is 1.1°C, extremes of 2.4°C above the observed summer record are simulated. This example represents a more than doubling of the magnitude of extremes, compared with global mean change, and such temperatures are unexpected based on the observed record alone. Projected extremes do not necessarily scale linearly with mean global warming, and this effect demonstrates the significant potential benefits of limiting warming to 1.5°C, compared to 2°C or warmer.

KIC 3240411 - the hottest known SPB star with the asymptotic g-mode period spacing

NASA Astrophysics Data System (ADS)

Szewczuk, Wojciech; Daszyńska-Daszkiewicz, Jadwiga

2018-05-01

We report the discovery of the hottest hybrid B-type pulsator, KIC 3240411, that exhibits the period spacing in the low-frequency range. This pattern is associated with asymptotic properties of high-order gravity (g-) modes. Our seismic modelling made simultaneously with the mode identification shows that dipole axisymmetric modes best fit the observations. Evolutionary models are computed with MESA code and pulsational models with the linear non-adiabatic code employing the traditional approximation to include the effects of rotation. The problem of mode excitation is discussed. We confirm that significant modification is indispensable to explain an instability of both pressure and gravity modes in the observed frequency ranges of KIC 3240411.

Taking the liability out of contaminated property transactions

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

Ayers, K.W.; Taylor, R.J.

Brownfield redevelopment has been one of the hottest environmental topics for the past several years. However, brownfields are only a small segment of the contaminated property transaction market that includes the sale of real estate, signing of leases, and mergers and acquisitions that involve the transfer of property impacted by environmental contamination. Historic site pollution creates problems due to strict, joint and several, and retroactive liability imposed by environmental laws. In response to the interest in contaminated properties, the environmental insurance industry has developed a number of products that cap the remediation costs and supplement or in many instances replacemore » indemnity agreements. These insurance products allow buyers, sellers, and remediation contractors to cap remediation costs, provide long-term warranties, manage balance sheet liabilities, and even allow PRPs to walk away from site cleanup and long-term operation and maintenance obligations.« less

Irrigation mitigates against heat extremes

NASA Astrophysics Data System (ADS)

Thiery, Wim; Fischer, Erich; Visser, Auke; Hirsch, Annette L.; Davin, Edouard L.; Lawrence, Dave; Hauser, Mathias; Seneviratne, Sonia I.

2017-04-01

Irrigation is an essential practice for sustaining global food production and many regional economies. Emerging scientific evidence indicates that irrigation substantially affects mean climate conditions in different regions of the world. Yet how this practice influences climate extremes is currently unknown. Here we use gridded observations and ensemble simulations with the Community Earth System Model to assess the impacts of irrigation on climate extremes. While the influence of irrigation on annual mean temperatures is limited, we find a large impact on temperature extremes, with a particularly strong cooling during the hottest day of the year (-0.78 K averaged over irrigated land). The strong influence on hot extremes stems from the timing of irrigation and its influence on land-atmosphere coupling strength. Together these effects result in asymmetric temperature responses, with a more pronounced cooling during hot and/or dry periods. The influence of irrigation is even more pronounced when considering subgrid-scale model output, suggesting that local effects of land management are far more important than previously thought. Finally we find that present-day irrigation is partly masking GHG-induced warming of extreme temperatures, with particularly strong effects in South Asia. Our results overall underline that irrigation substantially reduces our exposure to hot temperature extremes and highlight the need to account for irrigation in future climate projections.

A CHANDRA OBSERVATION OF THE ECLIPSING WOLF-RAYET BINARY CQ Cep

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

Skinner, Stephen L.; Zhekov, Svetozar A.; Güdel, Manuel

The short-period (1.64 d) near-contact eclipsing WN6+O9 binary system CQ Cep provides an ideal laboratory for testing the predictions of X-ray colliding wind shock theory at close separation where the winds may not have reached terminal speeds before colliding. We present results of a Chandra X-ray observation of CQ Cep spanning ∼1 day during which a simultaneous Chandra optical light curve was acquired. Our primary objective was to compare the observed X-ray properties with colliding wind shock theory, which predicts that the hottest shock plasma (T ≳ 20 MK) will form on or near the line-of-centers between the stars. The X-raymore » spectrum is strikingly similar to apparently single WN6 stars such as WR 134 and spectral lines reveal plasma over a broad range of temperatures T ∼ 4-40 MK. A deep optical eclipse was seen as the O star passed in front of the Wolf-Rayet star and we determine an orbital period P {sub orb} = 1.6412400 d. Somewhat surprisingly, no significant X-ray variability was detected. This implies that the hottest X-ray plasma is not confined to the region between the stars, at odds with the colliding wind picture and suggesting that other X-ray production mechanisms may be at work. Hydrodynamic simulations that account for such effects as radiative cooling and orbital motion will be needed to determine if the new Chandra results can be reconciled with the colliding wind picture.« less

Activity re-assignment and microclimate selection of free-living Arabian oryx: responses that could minimise the effects of climate change on homeostasis?

PubMed

Hetem, Robyn S; Strauss, W Maartin; Fick, Linda G; Maloney, Shane K; Meyer, Leith C R; Shobrak, Mohammed; Fuller, Andrea; Mitchell, Duncan

2012-12-01

Predicting whether behaviour could buffer the effects of climate change on long-lived mammals requires a better understanding of the long-term behavioural responses of mammals to environmental stress. Using biologging, we measured locomotor activity and microclimate selection, over eight months, in five Arabian oryx (Oryx leucoryx) living free in a Saudi Arabian desert. The oryx displayed seasonal flexibility in activity patterns, shifting from a continuous 24-h activity pattern with crepuscular peaks in cooler months to a predominantly nocturnal activity pattern during the hottest months, without reducing the total 24-h activity level. The proportion of total 24-h activity that occurred during daylight hours was just 29±8% during the hottest months, versus 53±8% (mean±SD, n=5 oryx) in the other months. The attenuation in diurnal activity levels during the hot months was accompanied by the selection of cooler microclimates, presumably via shade seeking, during the heat of the day. Analysis of miniature black globe (miniglobe) temperature from a remote sensor on the collar of two female animals revealed that oryx selected microclimates cooler than the microclimates in direct sun at higher environmental heat loads across all periods, but with enhanced efficiency during the dry periods. We have quantified activity re-assignment and microclimate selection as responses to hot arid conditions in a free-living artiodactyl. Such flexible behavioural processes may act to buffer the adverse effects of the progressively hotter and drier conditions predicted to occur with climate change. Copyright © 2012 Elsevier GmbH. All rights reserved.

Nest temperature fluctuations in a cavity nester, the southern ground-hornbill.

PubMed

Combrink, L; Combrink, H J; Botha, A J; Downs, C T

2017-05-01

Southern ground-hornbills Bucorvus leadbeateri inhabit savanna and bushveld regions of South Africa. They nest in the austral summer, which coincides with the wet season and hottest daytime temperatures in the region. They are secondary cavity nesters and typically nest in large cavities in trees, cliffs and earth banks, but readily use artificial nest boxes. Southern ground-hornbills are listed as Endangered in South Africa, with reintroductions into suitable areas highlighted as a viable conservation intervention for the species. Nest microclimate, and the possible implications this may have for the breeding biology of southern ground-hornbills, have never been investigated. We used temperature dataloggers to record nest cavity temperature and ambient temperature for one artificial and 11 natural southern ground-hornbill tree cavity nests combined, spanning two breeding seasons. Mean hourly nest temperature, as well as mean minimum and mean maximum nest temperature, differed significantly between southern ground-hornbill nests in both breeding seasons. Mean nest temperature also differed significantly from mean ambient temperature for both seasons. Natural nest cavities provided a buffer against the ambient temperature fluctuations. The artificial nest provided little insulation against temperature extremes, being warmer and cooler than the maximum and minimum local ambient temperatures, respectively. Nest cavity temperature was not found to have an influence on the breeding success of the southern ground-hornbill groups investigated in this study. These results have potentially important implications for southern ground-hornbill conservation and artificial nest design, as they suggest that the birds can tolerate greater nest cavity temperature extremes than previously thought. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mass loss, levitation, accretion, and the sharp-lined features in hot white dwarfs

NASA Technical Reports Server (NTRS)

Bruhweiler, F. C.; Kondo, Y.

1983-01-01

A study has been conducted of eight white dwarfs, including seven DA and one He-rich types. The study is based on high-resolution observations conducted with the aid of the International Ultraviolet Explorer. Four of the dwarfs show features related to heavy elements which are not interstellar in origin. It is tentatively suggested that, at least in the hottest low-gravity DA white dwarfs, the observed narrow-lined features are formed in expanding halos or winds associated with the white dwarfs. Theoretically, stable white dwarf halos should actually be coronae with temperatures in excess of 1,000,000 K. However, the observed narrow-lined features do not suggest such high temperatures. The observed radial velocities suggest weak stellar winds in two hot white dwarfs, namely, G191-B2B and 2111+49. It is tentatively proposed that radiative levitation can explain the appearance of the observed metallic lines in the hot DA white dwarfs.

FUSE Observations of Heavy Elements in the Photospheres of Cool DB White Dwarfs

NASA Astrophysics Data System (ADS)

Desharnais, S.; Wesemael, F.; Chayer, P.; Kruk, J. W.; Saffer, R. A.

2008-01-01

We present a comprehensive analysis of the far-ultraviolet spectra of five DB white dwarfs spanning the effective temperature range between 14,700 and 20,800 K. The FUSE line analysis shows that carbon features, previously observed in several hot DB stars at or above 22,000 K, are present in the two coolest (GD 408 and GD 378) and in the hottest (G270-124) target. The observed carbon abundances range from log N(C)/N(He) ~ - 6.9 to ~ - 8.8. In addition, four of the five objects display photospheric lines of silicon. Other elements such as oxygen, iron, and sulfur are also observed in some objects. The variations of the abundances of heavy elements as a function of effective temperature in DB stars are discussed in terms of a competition between a stellar wind, gravitational settling, accretion from interstellar (and circumstellar) matter, and convective dredge-up. FUSE is operated by the Johns Hopkins University under NASA contract NAS5-32985.

A series of shocks and edges in Abell 2219

DOE PAGES

Canning, R. E. A.; Allen, S. W.; Applegate, D. E.; ...

2016-09-22

Here, we present deep, 170 ks, Chandra X-ray observations of Abell 2219 (z = 0.23), one of the hottest and most X-ray luminous clusters known, and which is experiencing a major merger event. We discover a ‘horseshoe’ of high-temperature gas surrounding the ram-pressure-stripped, bright, hot, X-ray cores. We confirm an X-ray shock front located north-west of the X-ray centroid and along the projected merger axis. We also find a second shock front to the south-east of the X-ray centroid making this only the second cluster where both the shock and reverse shock are confirmed with X-ray temperature measurements. We alsomore » present evidence for a possible sloshing cold front in the ‘remnant tail’ of one of the sub-cluster cores. The cold front and north-west shock front geometrically bound the radio halo and appear to be directly influencing the radio properties of the cluster.« less

Human influence on Canadian temperatures

NASA Astrophysics Data System (ADS)

Wan, Hui; Zhang, Xuebin; Zwiers, Francis

2018-02-01

Canada has experienced some of the most rapid warming on Earth over the past few decades with a warming rate about twice that of the global mean temperature since 1948. Long-term warming is observed in Canada's annual, winter and summer mean temperatures, and in the annual coldest and hottest daytime and nighttime temperatures. The causes of these changes are assessed by comparing observed changes with climate model simulated responses to anthropogenic and natural (solar and volcanic) external forcings. Most of the observed warming of 1.7 °C increase in annual mean temperature during 1948-2012 [90% confidence interval (1.1°, 2.2 °C)] can only be explained by external forcing on the climate system, with anthropogenic influence being the dominant factor. It is estimated that anthropogenic forcing has contributed 1.0 °C (0.6°, 1.5 °C) and natural external forcing has contributed 0.2 °C (0.1°, 0.3 °C) to the observed warming. Up to 0.5 °C of the observed warming trend may be associated with low frequency variability of the climate such as that represented by the Pacific decadal oscillation (PDO) and North Atlantic oscillation (NAO). Overall, the influence of both anthropogenic and natural external forcing is clearly evident in Canada-wide mean and extreme temperatures, and can also be detected regionally over much of the country.

The hottest lavas of the Phanerozoic from a reservoir at the core-mantle boundary

NASA Astrophysics Data System (ADS)

Gazel, E.; Trela, J.; Sobolev, A. V.; Bizimis, M.; Jicha, B. R.; Batanova, V. G.

2017-12-01

Petrologic models suggest that modern plume-derived melts generate at high mantle temperatures (>1500 °C) relative to those produced at ambient mid-ocean ridge conditions ( 1350 °C). Earth's mantle has cooled during its history due to heat loss and decrease in radioactive heat production, thus the temperatures of these modern-day basalts are substantially lower than those produced during the Archean (>2.5 Ga), as recorded by komatiites (>1700 °C). Surprisingly, we discovered that the 90 Ma Galapagos-related Tortugal Suite accreted in Costa Rica not only records mantle potential temperatures as high as ancient Archean komatiites ( 1800 °C), but also the highest olivine-spinel crystallization temperatures ever reported ( 1600 °C). These new results from Tortugal (and other anomalously hot Phanerozoic locations) imply that if the mantle is still producing melts as hot as during the Archean, then there must exist reservoirs that preserve Archean temperatures at the base of the lower mantle. These anomalously hot reservoirs could be sustained over time by the steady-state temperature conditions at the core-mantle boundary buffered by the crystallization of Earth's core. Although our results suggest that even modern plumes can produce melts at similar P-T conditions as inferred during the Archean, these occurrences are not common as plumes will likely interact with the cooler ambient mantle.

Out on a limb: Thermal microenvironments in the tropical forest canopy and their relevance to ants.

PubMed

Stark, Alyssa Y; Adams, Benjamin J; Fredley, Jennifer L; Yanoviak, Stephen P

2017-10-01

Small, cursorial ectotherms like ants often are immersed in the superheated air layers that develop millimeters above exposed, insolated surfaces (i.e., the thermal boundary layer). We quantified the thermal microenvironments around tree branches in the tropical rainforest canopy, and explored the effects of substrate color on the internal body temperature and species composition of arboreal ants. Branch temperatures during the day (09:00-16:00) were hottest (often > 50°C) and most variable on the upper surface, while the lowest and least variable temperatures occurred on the underside. Temperatures on black substrates declined with increasing distance above the surface in both the field and the laboratory. By contrast, a micro-scale temperature inversion occurred above white substrates. Wind events (ca. 2ms -1 ) eliminated these patterns. Internal temperatures of bodies of Cephalotes atratus workers experimentally heated in the laboratory were 6°C warmer on white vs. black substrates, and 6°C cooler than ambient in windy conditions. The composition of ant species foraging at baits differed between black-painted and unpainted tree branches, with a tendency for smaller ants to avoid the significantly hotter black surfaces. Collectively, these outcomes show that ants traversing canopy branches experience very heterogeneous thermal microenvironments that are partly influenced in predictable ways by branch surface coloration and breezy conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Return levels of temperature extremes in southern Pakistan

NASA Astrophysics Data System (ADS)

Zahid, Maida; Blender, Richard; Lucarini, Valerio; Caterina Bramati, Maria

2017-12-01

Southern Pakistan (Sindh) is one of the hottest regions in the world and is highly vulnerable to temperature extremes. In order to improve rural and urban planning, it is useful to gather information about the recurrence of temperature extremes. In this work, return levels of the daily maximum temperature Tmax are estimated, as well as the daily maximum wet-bulb temperature TWmax extremes. We adopt the peaks over threshold (POT) method, which has not yet been used for similar studies in this region. Two main datasets are analyzed: temperatures observed at nine meteorological stations in southern Pakistan from 1980 to 2013, and the ERA-Interim (ECMWF reanalysis) data for the nearest corresponding locations. The analysis provides the 2-, 5-, 10-, 25-, 50-, and 100-year return levels (RLs) of temperature extremes. The 90 % quantile is found to be a suitable threshold for all stations. We find that the RLs of the observed Tmax are above 50 °C at northern stations and above 45 °C at the southern stations. The RLs of the observed TWmax exceed 35 °C in the region, which is considered as a limit of survivability. The RLs estimated from the ERA-Interim data are lower by 3 to 5 °C than the RLs assessed for the nine meteorological stations. A simple bias correction applied to ERA-Interim data improves the RLs remarkably, yet discrepancies are still present. The results have potential implications for the risk assessment of extreme temperatures in Sindh.

High-temperature responses of North American cacti

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

Smith, S.D.; Didden-Zopfy, B.; Nobel, P.S.

1984-04-01

High-temperature tolerances of 14 species of North American cacti were investigated. A reduction in the proportion of chlorenchyma cells taking up a vital stain (neutral red) and reduced nocturnal acid accumulation were used as indicators of high-temperature damage. All species tolerated relatively high tissue temperatures, the mean maximum tolerance being 64/sup 0/C, with an absolute maximum of 69/sup 0/ for two species of ferocactus. Such tissue tolerances to high temperature may be unsurpassed in vascular plants. Morphological features can affect tissue temperatures. Specifically, thin-stemmed species such as the cylindropuntias attain lower maximum temperatures under identical microclimatic conditions than do moremore » massive species; they also tend to be less tolerant of high-temperature stress. Stem diameter changes of three species of columnar ceriod cacti along a Sonoran Desert latitudinal transect were previously attributed to adaptation to progressively colder temperatures northward. Such changes can also be interpreted as a morphological adaptation to high temperatures, particularly in the southern Sonoran Desert. Interspecific differences in high-temperature tolerance may account for distributional differences among other species. Acclimation of high-temperature tolerances in response to increasing day/night air temperatures was observed in all 14 species, especially at higher growh temperatures. From 40/sup 0/ day/30/sup 0/ night to 50/sup 0//40/sup 0/, the tolerable tissue temperatures increased an average of 6/sup 0/. Half-times for the acclimation shifts were 1-3d. Although cacti attain extremely high tissue temperatures in desert habitats, tolerance of high temperatures and pronounced acclimation potential allow them to occur in some of the hottest habitats in North America.« less

Mammal extinctions, body size, and paleotemperature

USGS Publications Warehouse

Bown, T.M.; Holroyd, P.A.; Rose, K.D.

1994-01-01

There is a general inverse relationship between the natural logarithm of tooth area (a body size indicator) of some fossil mammals and paleotemperature during approximately 2.9 million years of the early Eocene in the Bighorn Basin of northwest Wyoming. When mean temperatures became warmer, tooth areas tended to become smaller. During colder times, larger species predominated; these generally became larger or remained the same size. Paleotemperature trends also markedly affected patterns of local (and, perhaps, regional) extinction and immigration. New species appeared as immigrants during or near the hottest (smaller forms) and coldest (larger forms) intervals. Paleotemperature trend reversals commonly resulted in the ultimate extinction of both small forms (during cooling intervals) and larger forms (during warming intervals). These immigrations and extinctions mark faunal turnovers that were also modulated by sharp increases in sediment accumulation rate.

Hubble/WFC3 Spectroscopy of the Transiting Exoplanets WASP-19b and WASP-17b

NASA Technical Reports Server (NTRS)

Mandell, A.; Haynes, K.; Sinukoff, E.; Deming, D.; Wlikins, A.; Madhusudhan, N.; Agol, E.; Burrows, A.; Charbonneau, D.; Gilliland, R.;

Detrimental influence on performance of high temperature incubation in a tropical reptile: is cooler better in the tropics?

PubMed

Bell, Kris; Blomberg, Simon; Schwarzkopf, Lin

2013-01-01

Global temperatures have risen over the last century, and are forecast to continue rising. Ectotherms may be particularly sensitive to changes in thermal regimes, and tropical ectotherms are more likely than temperate species to be influenced by changes in environmental temperature, because they may have evolved narrow thermal tolerances. Keelback snakes (Tropidonophis mairii) are tropical, oviparous reptiles. To quantify the effects of temperature on the morphology and physiology of hatchling keelbacks, clutches laid by wild-caught females were split and incubated at three temperatures, reflecting the average minimum, overall average and average maximum temperatures recorded at our study site. Upon hatching, the performance of neonates was examined at all three incubation temperatures in a randomized order over consecutive days. Hatchlings from the 'hot' treatment had slower burst swim speeds and swam fewer laps than hatchlings from the cooler incubation temperatures in all three test temperatures, indicating a low thermal optimum for incubation of this tropical species. There were no significant interactions between test temperature and incubation temperature across performance variables, suggesting phenotypic differences caused by incubation temperature did not acclimate this species to post-hatching conditions. Thus, keelback embryos appear evolutionarily adapted to development at cooler temperatures (relative to what is available in their habitat). The considerable reduction in hatchling viability and performance associated with a 3.5 °C increase in incubation temperature, suggests climate change may have significant population-level effects on this species. However, the offspring of three mothers exposed to the hottest incubation temperature were apparently resilient to high temperature, suggesting that this species may respond to selection imposed by thermal regime.

High Temperature Water Heat Pipes Radiator for a Brayton Space Reactor Power System

NASA Astrophysics Data System (ADS)

El-Genk, Mohamed S.; Tournier, Jean-Michel

2006-01-01

A high temperature water heat pipes radiator design is developed for a space power system with a sectored gas-cooled reactor and three Closed Brayton Cycle (CBC) engines, for avoidance of single point failures in reactor cooling and energy conversion and rejection. The CBC engines operate at turbine inlet and exit temperatures of 1144 K and 952 K. They have a net efficiency of 19.4% and each provides 30.5 kWe of net electrical power to the load. A He-Xe gas mixture serves as the turbine working fluid and cools the reactor core, entering at 904 K and exiting at 1149 K. Each CBC loop is coupled to a reactor sector, which is neutronically and thermally coupled, but hydraulically decoupled to the other two sectors, and to a NaK-78 secondary loop with two water heat pipes radiator panels. The segmented panels each consist of a forward fixed segment and two rear deployable segments, operating hydraulically in parallel. The deployed radiator has an effective surface area of 203 m2, and when the rear segments are folded, the stowed power system fits in the launch bay of the DELTA-IV Heavy launch vehicle. For enhanced reliability, the water heat pipes operate below 50% of their wicking limit; the sonic limit is not a concern because of the water, high vapor pressure at the temperatures of interest (384 - 491 K). The rejected power by the radiator peaks when the ratio of the lengths of evaporator sections of the longest and shortest heat pipes is the same as that of the major and minor widths of the segments. The shortest and hottest heat pipes in the rear segments operate at 491 K and 2.24 MPa, and each rejects 154 W. The longest heat pipes operate cooler (427 K and 0.52 MPa) and because they are 69% longer, reject more power (200 W each). The longest and hottest heat pipes in the forward segments reject the largest power (320 W each) while operating at ~ 46% of capillary limit. The vapor temperature and pressure in these heat pipes are 485 K and 1.97 MPa. By contrast, the shortest water heat pipes in the forward segments operate much cooler (427 K and 0.52 MPa), and reject a much lower power of 45 W each. The radiator with six fixed and 12 rear deployable segments rejects a total of 324 kWth, weights 994 kg and has an average specific power of 326 Wth/kg and a specific mass of 5.88 kg/m2.

Physiological responses of Bos taurus and Bos indicus cattle to prolonged, continuous heat and humidity.

PubMed

Beatty, D T; Barnes, A; Taylor, E; Pethick, D; McCarthy, M; Maloney, S K

2006-04-01

Two experiments were conducted to investigate the physiological responses of Bos taurus (Angus cross, n = 6) and Bos indicus (Brahman, n = 6) cattle to prolonged heat and humidity, as can occur during live export by sea. Each experiment was carried out in climate-controlled rooms, where heifers were exposed to 15 d of sustained heat and humidity. The treatment was designed to be representative of a long-haul, live-export voyage leaving a southern Australian winter and traveling to a Middle Eastern summer. Wet bulb temperature (WBT) was used to give a combined measure of dry bulb temperature and relative humidity and was increased over several days, culminating in 5 d at 32 degrees C WBT between d 7 and 11. By d 11, the respiratory rate and core body temperature increased (P < 0.001) compared with values at lower ambient temperature on d 1 and 2 when climate-controlled rooms were not operating. Feed intake of Bos taurus was reduced (P < 0.001) by d 11, whereas that of Bos indicus did not change (P = 0.14). Despite no diurnal variation in climatic conditions, core body temperature of both Bos taurus and Bos indicus continued to show a circadian amplitude of approximately 1 degrees C throughout the hottest period. This amplitude increased during the recovery period after heat was removed (up to 1.8 degrees C for Bos indicus and 1.6 degrees C for Bos taurus). Water intake for both Bos taurus and Bos indicus increased when WBT increased (P < 0.01 on d 11). Significant acid-base and blood electrolyte imbalances occurred in both Bos taurus and Bos indicus, with changes in Bos taurus being more substantial and prolonged. The increase in respiratory rate coincided with a decrease in the partial pressures of carbon dioxide and bicarbonate in venous blood. However, during the hottest period, average daily venous blood pH remained unchanged. When the heat load was reduced after d 11, the blood pH decreased, indicating metabolic acidosis. Blood pH declined from 7.44 to 7.36 for Bos taurus (P < 0.001) and from 7.44 to 7.38 for Bos indicus (P < 0.001). Other parameters measured include heart rate; packed cell volume; plasma and urine Na, K, and Cl; urine pH; and specific gravity. Our results suggest that Bos taurus cattle experience significant physiological changes during exposure to prolonged and continuous high heat and humidity, with alterations persisting for some days after the heat-stress conditions subside. Bos indicus experience similar but less pronounced physiological changes.

Superensemble of a Regional Climate Model for the Western US using Climateprediction.net

NASA Astrophysics Data System (ADS)

Mote, P.; Salahuddin, A.; Allen, M.; Jones, R.

2010-12-01

For over a decade, a citizen science experiment called climateprediction.net organized by Oxford University has used computer time contributed by over 80,000 volunteers around the world to create superensembles of global climate simulations. A new climateprediction.net experiment built by the UK Meteorological Office and Oxford, and released in late summer 2010, brings these computing resources to bear on regional climate modeling for the Western US, western Europe, and southern Africa. For the western US, the spatial resolution of 25km permits important topological features -- mountain ranges and valleys -- to be resolved and to influence simulated climate, which consequently includes many important observed features of climate like the fact that California’s Central Valley is hottest at the north and south ends in summer, and cooler in the middle owing to the maritime influence that leaks through the gap in the coast range in the San Francisco area. We designed the output variables to satisfy both research needs and societal and environmental impacts needs. These include atmospheric circulation on regional and global scales, surface fluxes of energy, and hydrologic variables; extremes of temperature, precipitation, and wind; and derived quantities like frost days and number of consecutive dry days. Early results from pre-release beta testing suggest that the simulated fields compare favorably with available observations, and that the model performs as well in the distributed computing environment as on a dedicated high-performance machine. The advantages of a superensemble in interpreting regional climate change will permit an unprecedented combination of statistical completeness and spatial resolution.

Far-UV spectroscopy of two extremely hot, helium-rich white dwarfs

NASA Astrophysics Data System (ADS)

Werner, K.; Rauch, T.; Kruk, J. W.

2017-05-01

A large proportion of hot post-asymptotic giant branch stars and white dwarfs (WDs) are hydrogen-deficient. Two distinct evolutionary sequences have been identified. One of them comprises stars of spectral type [WC] and PG1159, and it originates from a late helium-shell flash, creating helium-rich stellar atmospheres with significant admixtures of carbon (up to about 50%, mass fraction). The other sequence comprises stars of spectral type O(He) and luminous subdwarf O stars which possibly are descendants of RCrB stars and extreme helium stars. Their carbon abundances are significantly lower (of the order of 1% or less) and it is thought that they originate from binary-star evolution (through merger or common-envelope evolution). Here we investigate two of the three hottest known helium-rich (DO) WDs (PG 1034+001 and PG 0038+199). They are the only ones for which spectra were recorded with the Far Ultraviolet Spectroscopic Explorer and the Hubble Space Telescope, allowing a comprehensive ultraviolet spectral analysis. We find effective temperatures of Teff = 115 000 ± 5000 K and 125 000 ± 5000 K, respectively, and a surface gravity of log g= 7 ± 0.5. In both stars, nitrogen is strongly oversolar while C and O are significantly subsolar. For all other assessed metals (Ne, Si, P, S, Ar, Fe, and Ni) we find abundances close to solar. We conclude that these WDs are immediate descendants of O(He) stars and, hence, result from close-binary evolution. Based on observations made with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer.

Simulating US Agriculture in a Modern Dust Bowl Drought

NASA Technical Reports Server (NTRS)

Glotter, Michael; Elliott, Joshua

2016-01-01

Drought-induced agricultural loss is one of the most costly impacts of extreme weather, and without mitigation, climate change is likely to increase the severity and frequency of future droughts. The Dust Bowl of the 1930s was the driest and hottest for agriculture in modern US history. Improvements in farming practices have increased productivity, but yields today are still tightly linked to climate variation and the impacts of a 1930s-type drought on current and future agricultural systems remain unclear. Simulations of biophysical process and empirical models suggest that Dust-Bowl-type droughts today would have unprecedented consequences, with yield losses approx.50% larger than the severe drought of 2012. Damages at these extremes are highly sensitive to temperature, worsening by approx.25% with each degree centigrade of warming. We find that high temperatures can be more damaging than rainfall deficit, and, without adaptation, warmer mid-century temperatures with even average precipitation could lead to maize losses equivalent to the Dust Bowl drought. Warmer temperatures alongside consecutive droughts could make up to 85% of rain-fed maize at risk of changes that may persist for decades. Understanding the interactions of weather extremes and a changing agricultural system is therefore critical to effectively respond to, and minimize, the impacts of the next extreme drought event.

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

Thiery, Wim; Davin, Edouard L.; Lawrence, David M.

Irrigation is an essential practice for sustaining global food production and many regional economies. Emerging scientific evidence indicates that irrigation substantially affects mean climate conditions in different regions of the world. Yet how this practice influences climate extremes is currently unknown. Here we use ensemble simulations with the Community Earth System Model to assess the impacts of irrigation on climate extremes. An evaluation of the model performance reveals that irrigation has a small yet overall beneficial effect on the representation of present-day near-surface climate. While the influence of irrigation on annual mean temperatures is limited, we find a large impactmore » on temperature extremes, with a particularly strong cooling during the hottest day of the year (-0.78 K averaged over irrigated land). The strong influence on extremes stems from the timing of irrigation and its influence on land-atmosphere coupling strength. Together these effects result in asymmetric temperature responses, with a more pronounced cooling during hot and/or dry periods. The influence of irrigation is even more pronounced when considering subgrid-scale model output, suggesting that local effects of land management are far more important than previously thought. In conclusion, our results underline that irrigation has substantially reduced our exposure to hot temperature extremes in the past and highlight the need to account for irrigation in future climate projections.« less

Present-day irrigation mitigates heat extremes

NASA Astrophysics Data System (ADS)

Thiery, Wim; Davin, Edouard L.; Lawrence, David M.; Hirsch, Annette L.; Hauser, Mathias; Seneviratne, Sonia I.

2017-02-01

Irrigation is an essential practice for sustaining global food production and many regional economies. Emerging scientific evidence indicates that irrigation substantially affects mean climate conditions in different regions of the world. Yet how this practice influences climate extremes is currently unknown. Here we use ensemble simulations with the Community Earth System Model to assess the impacts of irrigation on climate extremes. An evaluation of the model performance reveals that irrigation has a small yet overall beneficial effect on the representation of present-day near-surface climate. While the influence of irrigation on annual mean temperatures is limited, we find a large impact on temperature extremes, with a particularly strong cooling during the hottest day of the year (-0.78 K averaged over irrigated land). The strong influence on extremes stems from the timing of irrigation and its influence on land-atmosphere coupling strength. Together these effects result in asymmetric temperature responses, with a more pronounced cooling during hot and/or dry periods. The influence of irrigation is even more pronounced when considering subgrid-scale model output, suggesting that local effects of land management are far more important than previously thought. Our results underline that irrigation has substantially reduced our exposure to hot temperature extremes in the past and highlight the need to account for irrigation in future climate projections.

Multiphase groundwater flow near cooling plutons

USGS Publications Warehouse

Hayba, D.O.; Ingebritsen, S.E.

1997-01-01

We investigate groundwater flow near cooling plutons with a computer program that can model multiphase flow, temperatures up to 1200??C, thermal pressurization, and temperature-dependent rock properties. A series of experiments examines the effects of host-rock permeability, size and depth of pluton emplacement, single versus multiple intrusions, the influence of a caprock, and the impact of topographically driven groundwater flow. We also reproduce and evaluate some of the pioneering numerical experiments on flow around plutons. Host-rock permeability is the principal factor influencing fluid circulation and heat transfer in hydrothermal systems. The hottest and most steam-rich systems develop where permeability is of the order of 10-15 m2. Temperatures and life spans of systems decrease with increasing permeability. Conduction-dominated systems, in which permeabilities are ???10-16m2, persist longer but exhibit relatively modest increases in near-surface temperatures relative to ambient conditions. Pluton size, emplacement depth, and initial thermal conditions have less influence on hydrothermal circulation patterns but affect the extent of boiling and duration of hydrothermal systems. Topographically driven groundwater flow can significantly alter hydrothermal circulation; however, a low-permeability caprock effectively decouples the topographically and density-driven systems and stabilizes the mixing interface between them thereby defining a likely ore-forming environment.

Simulating US agriculture in a modern Dust Bowl drought.

PubMed

Glotter, Michael; Elliott, Joshua

2016-12-12

Drought-induced agricultural loss is one of the most costly impacts of extreme weather 1-3 , and without mitigation, climate change is likely to increase the severity and frequency of future droughts 4,5 . The Dust Bowl of the 1930s was the driest and hottest for agriculture in modern US history. Improvements in farming practices have increased productivity, but yields today are still tightly linked to climate variation 6 and the impacts of a 1930s-type drought on current and future agricultural systems remain unclear. Simulations of biophysical process and empirical models suggest that Dust-Bowl-type droughts today would have unprecedented consequences, with yield losses ∼50% larger than the severe drought of 2012. Damages at these extremes are highly sensitive to temperature, worsening by ∼25% with each degree centigrade of warming. We find that high temperatures can be more damaging than rainfall deficit, and, without adaptation, warmer mid-century temperatures with even average precipitation could lead to maize losses equivalent to the Dust Bowl drought. Warmer temperatures alongside consecutive droughts could make up to 85% of rain-fed maize at risk of changes that may persist for decades. Understanding the interactions of weather extremes and a changing agricultural system is therefore critical to effectively respond to, and minimize, the impacts of the next extreme drought event.

Mammalian metabolic rates in the hottest fish on earth.

PubMed

Wood, Chris M; Brix, Kevin V; De Boeck, Gudrun; Bergman, Harold L; Bianchini, Adalto; Bianchini, Lucas F; Maina, John N; Johannsson, Ora E; Kavembe, Geraldine D; Papah, Michael B; Letura, Kisipan M; Ojoo, Rodi O

2016-06-03

The Magadi tilapia, Alcolapia grahami, a small cichlid fish of Lake Magadi, Kenya lives in one of the most challenging aquatic environments on earth, characterized by very high alkalinity, unusual water chemistry, and extreme O2, ROS, and temperature regimes. In contrast to most fishes which live at temperatures substantially lower than the 36-40 °C of mammals and birds, an isolated population (South West Hot Springs, SWHS) of Magadi tilapia thrives in fast-flowing hotsprings with daytime highs of 43 °C and night-time lows of 32 °C. Another population (Fish Springs Lagoon, FSL) lives in a lagoon with fairly stable daily temperatures (33-36 °C). The upper critical temperatures (Ctmax) of both populations are very high; moreover the SWHS tilapia exhibit the highest Ctmax (45.6 °C) ever recorded for a fish. Routine rates of O2 consumption (MO2) measured on site, together with MO2 and swimming performance at 25, 32, and 39 °C in the laboratory, showed that the SWHS tilapia exhibited the greatest metabolic performance ever recorded in a fish. These rates were in the basal range of a small mammal of comparable size, and were all far higher than in the FSL fish. The SWHS tilapia represents a bellwether organism for global warming.

Space-dependent characterization of laser-induced plasma plume during fiber laser welding

NASA Astrophysics Data System (ADS)

Xiao, Xianfeng; Song, Lijun; Xiao, Wenjia; Liu, Xingbo

2016-12-01

The role of a plasma plume in high power fiber laser welding is of considerable interest due to its influence on the energy transfer mechanism. In this study, the space-dependent plasma characteristics including spectrum intensity, plasma temperature and electron density were investigated using optical emission spectroscopy technique. The plasma temperature was calculated using the Boltzmann plot of atomic iron lines, whereas the electron density was determined from the Stark broadening of the Fe I line at 381.584 nm. Quantitative analysis of plasma characteristics with respect to the laser radiation was performed. The results show that the plasma radiation increases as the laser power increases during the partial penetration mode, and then decreases sharply after the initiation of full penetration. Both the plasma temperature and electron density increase with the increase of laser power until they reach steady state values after full penetration. Moreover, the hottest core of the plasma shifts toward the surface of the workpiece as the penetration depth increases, whereas the electron density is more evenly distributed above the surface of the workpiece. The results also indicate that the absorption and scattering of nanoparticles in the plasma plume is the main mechanism for laser power attenuation.

Thermo-mechanical analysis of an internal cooling system with various configurations of a combustion liner after shell

NASA Astrophysics Data System (ADS)

Moon, Hokyu; Kim, Kyung Min; Park, Jun Su; Kim, Beom Seok; Cho, Hyung Hee

2015-12-01

The after-shell section, which is part of the gas turbine combustion liner, is exposed to the hottest combustion gas. Various cooling schemes have been applied to protect against severe thermal load. However, there is a significant discrepancy in the thermal expansion with large temperature differences, resulting in thermo-mechanical crack formation. In this study, to reduce combustion liner damage, thermo-mechanical analysis was conducted on three after-shell section configurations: inline-discrete divider wall, staggered divider wall, and swirler wall arrays. These array components are well-known heat-transfer enhancement structures in the duct. In the numerical analyses, the heat transfer characteristics, temperature and thermo-mechanical stress distribution were evaluated using finite volume method and finite element method commercial codes. As a result, we demonstrated that the temperature and the thermo-mechanical stress distribution were readily dependent on the structural array for cooling effectiveness and structural support in each modified cooling system. Compared with the reference model, the swirler wall array was most effective in diminishing the thermo-mechanical stress concentration, especially on the inner ring that is vulnerable to crack formation.

Effects of Roof-Edge Roughness on Air Temperature and Pollutant Concentration in Urban Canyons

NASA Astrophysics Data System (ADS)

Aliabadi, Amir A.; Krayenhoff, E. Scott; Nazarian, Negin; Chew, Lup Wai; Armstrong, Peter R.; Afshari, Afshin; Norford, Leslie K.

2017-08-01

The influence of roof-edge roughness elements on airflow, heat transfer, and street-level pollutant transport inside and above a two-dimensional urban canyon is analyzed using an urban energy balance model coupled to a large-eddy simulation model. Simulations are performed for cold (early morning) and hot (mid afternoon) periods during the hottest month of the year (August) for the climate of Abu Dhabi, United Arab Emirates. The analysis suggests that early in the morning, and when the tallest roughness elements are implemented, the temperature above the street level increases on average by 0.5 K, while the pollutant concentration decreases by 2% of the street-level concentration. For the same conditions in mid afternoon, the temperature decreases conservatively by 1 K, while the pollutant concentration increases by 7% of the street-level concentration. As a passive or active architectural solution, the roof roughness element shows promise for improving thermal comfort and air quality in the canyon for specific times, but this should be further verified experimentally. The results also warrant a closer look at the effects of mid-range roughness elements in the urban morphology on atmospheric dynamics so as to improve parametrizations in mesoscale modelling.

Do cities simulate climate change? A comparison of herbivore response to urban and global warming

USGS Publications Warehouse

Youngsteadt, Elsa; Dale, Adam G.; Terando, Adam; Dunn, Robert R.; Frank, Steven D.

2014-01-01

Cities experience elevated temperature, CO2, and nitrogen deposition decades ahead of the global average, such that biological response to urbanization may predict response to future climate change. This hypothesis remains untested due to a lack of complementary urban and long-term observations. Here, we examine the response of an herbivore, the scale insect Melanaspis tenebricosa, to temperature in the context of an urban heat island, a series of historical temperature fluctuations, and recent climate warming. We survey M. tenebricosa on 55 urban street trees in Raleigh, NC, 342 herbarium specimens collected in the rural southeastern United States from 1895 to 2011, and at 20 rural forest sites represented by both modern (2013) and historical samples. We relate scale insect abundance to August temperatures and find that M. tenebricosa is most common in the hottest parts of the city, on historical specimens collected during warm time periods, and in present-day rural forests compared to the same sites when they were cooler. Scale insects reached their highest densities in the city, but abundance peaked at similar temperatures in urban and historical datasets and tracked temperature on a decadal scale. Although urban habitats are highly modified, species response to a key abiotic factor, temperature, was consistent across urban and rural-forest ecosystems. Cities may be an appropriate but underused system for developing and testing hypotheses about biological effects of climate change. Future work should test the applicability of this model to other groups of organisms.

Whole season compared to growth-stage resolved temperature trends: implications for US maize yield

NASA Astrophysics Data System (ADS)

Butler, E. E.; Mueller, N. D.; Huybers, P. J.

2014-12-01

The effect of temperature on maize yield has generally been considered using a single value for the entire growing season. We compare the effect of temperature trends on yield between two distinct models: a single temperature sensitivity for the whole season and a variable sensitivity across four distinct agronomic development stages. The more resolved variable-sensitivity model indicates roughly a factor of two greater influence of temperature on yield than that implied by the single-sensitivity model. The largest discrepancies occur in silking, which is demonstrated to be the most sensitive stage in the variable-sensitivity model. For instance, whereas median yields are observed to be only 53% of typical values during the hottest 1% of silking-stage temperatures, the single-sensitivity model over predicts median yields of 68% whereas the variable-sensitivity model more correctly predicts median yields of 61%. That the variable sensitivity model is also not capable of capturing the full extent of yield losses suggests that further refinement to represent the non-linear response would be useful. Results from the variable sensitivity model also indicate that management decisions regarding planting times, which have generally shifted toward earlier dates, have led to greater yield benefit than that implied by the single-sensitivity model. Together, the variation of both temperature trends and yield variability within growing stages calls for closer attention to how changes in management interact with changes in climate to ultimately affect yields.

The Hottest Horizontal-Branch Stars in Omega Centauri: Late Hot Flasher vs. Helium Enrichment

NASA Technical Reports Server (NTRS)

Moehler, S.; Dreizler, S.; Lanz, T.; Bono, G.; Sweigart, A V.; Calamida, A.; Monelli, M.; Nonino, M.

2007-01-01

UV observations of some massive globular clusters uncovered a significant population of very hot stars below the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either by the late hot flasher scenario here stars experience the helium flash while on the white dwarf cooling curve or by the helium-rich sub-population recently postulated to exist in some clusters. Spectroscopic analyses of blue hook stars in omega Cen and NGC 2808 support the late hot flasher scenario, but the stars contain much less helium than expected and the predicted C, N enrichment could not be verified from existing data. We want to determine effective temperatures, surface gravities and abundances of He, C, N in blue hook and canonical extreme horizontal branch (EHB) star candidates. Moderately high resolution spectra of stars at the hot end of the blue horizontal branch in the globular cluster omega Cen were analysed for atmospheric parameters (T(sub eff), log g) and abundances using LTE and Non-LTE model atmospheres. In the temperature range 30,000 K to 50,000 K we find that 37% of our stars are helium-poor (log nHe/nH less than -2), 49% have solar helium abundance within a factor of 3 (-1.5 less than or equal to log nHe/nH less than or equal to -0.5) and 14% are helium rich (log nHe/nH greater than -0.4). We also find carbon enrichment in step with helium enrichment, with a maximum carbon enrichment of 3% by mass. At least 30% of the hottest HB stars in omega Centauri show helium abundances well above the predictions from the helium enrichment scenario (Y = 0.42 corresponding to log nHe/nH approximately equal to -0.74). In addition the most helium-rich stars show strong carbon enrichment as predicted by the late hot flasher scenario. We conclude that the helium-rich HB stars in omega Cen cannot be explained solely by the helium-enrichment scenario invoked to explain the blue main sequence.

Relationship between seasonal weather changes, risk of dehydration, and incidence of severe bradyarrhythmias requiring urgent temporary transvenous cardiac pacing in an elderly population

NASA Astrophysics Data System (ADS)

Palmisano, Pietro; Accogli, Michele; Zaccaria, Maria; Vergari, Alessandra; De Luca De Masi, Gabriele; Negro, Luca; De Blasi, Sergio

2014-09-01

There is little information on any seasonal variations or meteorological factors associated with symptomatic bradyarrhythmias requiring cardiac pacing. The aim of this single-center study was to investigate the seasonal distribution of the incidence of severe, life-threatening bradyarrhythmias requiring urgent temporary transvenous cardiac pacing in an elderly population. Consecutive patients who underwent urgent temporary transvenous cardiac pacing between 2007 and 2012 were enrolled. The baseline characteristics of the patients and some meteorological parameters, including the calculation the daily heat index (HI), were recorded. During the study period, 79 consecutive patients (mean age 82 ± 8 years, 41 % male) underwent urgent temporary transvenous cardiac pacing, mainly for third-degree atrioventricular block (79 %). The incidence of bradyarrhythmias was significantly higher in summer than in the other seasons ( P < 0.001). Moreover, the highest incidence was observed in months with HI > 90 °F for >3 h per day for at least 10 days ( P < 0.001). A direct correlation was found between the average monthly temperature and the monthly number of patients undergoing temporary cardiac pacing (r = 0.54, P < 0.001). Compared with other patients, those observed during the hottest months were significantly older and more frequently affected by chronic disabling neurological diseases (all P < 0.05). In addition, they more frequently showed biochemical indices of dehydration, renal function impairment and hyperkalemia (all P < 0.05). This study showed an increased incidence of severe bradyarrhythmias in an elderly population during the hottest months of the year. In these months, in subjects characterized by increased susceptibility to dehydration, the risk of developing bradyarrhythmias was increased significantly.

Spatially explicit estimation of heat stress-related impacts of climate change on the milk production of dairy cows in the United Kingdom.

PubMed

Fodor, Nándor; Foskolos, Andreas; Topp, Cairistiona F E; Moorby, Jon M; Pásztor, László; Foyer, Christine H

2018-01-01

Dairy farming is one the most important sectors of United Kingdom (UK) agriculture. It faces major challenges due to climate change, which will have direct impacts on dairy cows as a result of heat stress. In the absence of adaptations, this could potentially lead to considerable milk loss. Using an 11-member climate projection ensemble, as well as an ensemble of 18 milk loss estimation methods, temporal changes in milk production of UK dairy cows were estimated for the 21st century at a 25 km resolution in a spatially-explicit way. While increases in UK temperatures are projected to lead to relatively low average annual milk losses, even for southern UK regions (<180 kg/cow), the 'hottest' 25×25 km grid cell in the hottest year in the 2090s, showed an annual milk loss exceeding 1300 kg/cow. This figure represents approximately 17% of the potential milk production of today's average cow. Despite the potential considerable inter-annual variability of annual milk loss, as well as the large differences between the climate projections, the variety of calculation methods is likely to introduce even greater uncertainty into milk loss estimations. To address this issue, a novel, more biologically-appropriate mechanism of estimating milk loss is proposed that provides more realistic future projections. We conclude that South West England is the region most vulnerable to climate change economically, because it is characterised by a high dairy herd density and therefore potentially high heat stress-related milk loss. In the absence of mitigation measures, estimated heat stress-related annual income loss for this region by the end of this century may reach £13.4M in average years and £33.8M in extreme years.

The 2011 heat wave in Greater Houston: Effects of land use on temperature.

PubMed

Zhou, Weihe; Ji, Shuang; Chen, Tsun-Hsuan; Hou, Yi; Zhang, Kai

2014-11-01

Effects of land use on temperatures during severe heat waves have been rarely studied. This paper examines land use-temperature associations during the 2011 heat wave in Greater Houston. We obtained high resolution of satellite-derived land use data from the US National Land Cover Database, and temperature observations at 138 weather stations from Weather Underground, Inc (WU) during the August of 2011, which was the hottest month in Houston since 1889. Land use regression and quantile regression methods were applied to the monthly averages of daily maximum/mean/minimum temperatures and 114 land use-related predictors. Although selected variables vary with temperature metric, distance to the coastline consistently appears among all models. Other variables are generally related to high developed intensity, open water or wetlands. In addition, our quantile regression analysis shows that distance to the coastline and high developed intensity areas have larger impacts on daily average temperatures at higher quantiles, and open water area has greater impacts on daily minimum temperatures at lower quantiles. By utilizing both land use regression and quantile regression on a recent heat wave in one of the largest US metropolitan areas, this paper provides a new perspective on the impacts of land use on temperatures. Our models can provide estimates of heat exposures for epidemiological studies, and our findings can be combined with demographic variables, air conditioning and relevant diseases information to identify 'hot spots' of population vulnerability for public health interventions to reduce heat-related health effects during heat waves. Copyright © 2014 Elsevier Inc. All rights reserved.

Selected Heat-Sensitive Antibiotics Are Not Inactivated During Polymethylmethacrylate Curing and Can Be Used in Cement Spacers for Periprosthetic Joint Infection.

PubMed

Carli, Alberto V; Sethuraman, Arvinth S; Bhimani, Samrath J; Ross, Frederick P; Bostrom, Mathias P G

2018-06-01

Antibiotic use in polymethylmethacrylate (PMMA) spacers has historically been limited to those which are "heat-stable" and thus retain their antimicrobial properties after exposure to the high temperatures which occur during PMMA curing. This study examines the requirement of "heat stability" by measuring temperatures of Palacos and Simplex PMMA as they cure inside commercial silicone molds of the distal femur and proximal tibia. Temperature probes attached to thermocouples were placed at various depths inside the molds and temperatures were recorded for 20 minutes after PMMA introduced and a temperature curve for each PMMA product was determined. A "heat-stable" antibiotic, vancomycin, and a "heat-sensitive" antibiotic, ceftazidime, were placed in a programmable thermocycler and exposed to the same profile of PMMA curing temperatures. Antimicrobial activity against Staphylococcus aureus was compared for heat-treated antibiotics vs room temperature controls. Peak PMMA temperatures were significantly higher in tibial (115.2°C) vs femoral (85.1°C; P < .001) spacers. In the hottest spacers, temperatures exceeded 100°C for 3 minutes. Simplex PMMA produced significantly higher temperatures (P < .05) compared with Palacos. Vancomycin bioactivity did not change against S aureus with heat exposure. Ceftazidime bioactivity did not change when exposed to femoral temperature profiles and was reduced only 2-fold with tibial profiles. The curing temperatures of PMMA in knee spacers are not high enough or maintained long enough to significantly affect the antimicrobial efficacy of ceftazidime, a known "heat-sensitive" antibiotic. Future studies should investigate if more "heat-sensitive" antibiotics could be used clinically in PMMA spacers. Copyright © 2018 Elsevier Inc. All rights reserved.

Hardware/Software Data Acquisition System for Real Time Cell Temperature Monitoring in Air-Cooled Polymer Electrolyte Fuel Cells

PubMed Central

Bartolucci, Veronica

2017-01-01

This work presents a hardware/software data acquisition system developed for monitoring the temperature in real time of the cells in Air-Cooled Polymer Electrolyte Fuel Cells (AC-PEFC). These fuel cells are of great interest because they can carry out, in a single operation, the processes of oxidation and refrigeration. This allows reduction of weight, volume, cost and complexity of the control system in the AC-PEFC. In this type of PEFC (and in general in any PEFC), the reliable monitoring of temperature along the entire surface of the stack is fundamental, since a suitable temperature and a regular distribution thereof, are key for a better performance of the stack and a longer lifetime under the best operating conditions. The developed data acquisition (DAQ) system can perform non-intrusive temperature measurements of each individual cell of an AC-PEFC stack of any power (from watts to kilowatts). The stack power is related to the temperature gradient; i.e., a higher power corresponds to a higher stack surface, and consequently higher temperature difference between the coldest and the hottest point. The developed DAQ system has been implemented with the low-cost open-source platform Arduino, and it is completed with a modular virtual instrument that has been developed using NI LabVIEW. Temperature vs time evolution of all the cells of an AC-PEFC both together and individually can be registered and supervised. The paper explains comprehensively the developed DAQ system together with experimental results that demonstrate the suitability of the system. PMID:28698497

Hardware/Software Data Acquisition System for Real Time Cell Temperature Monitoring in Air-Cooled Polymer Electrolyte Fuel Cells.

PubMed

Segura, Francisca; Bartolucci, Veronica; Andújar, José Manuel

2017-07-09

This work presents a hardware/software data acquisition system developed for monitoring the temperature in real time of the cells in Air-Cooled Polymer Electrolyte Fuel Cells (AC-PEFC). These fuel cells are of great interest because they can carry out, in a single operation, the processes of oxidation and refrigeration. This allows reduction of weight, volume, cost and complexity of the control system in the AC-PEFC. In this type of PEFC (and in general in any PEFC), the reliable monitoring of temperature along the entire surface of the stack is fundamental, since a suitable temperature and a regular distribution thereof, are key for a better performance of the stack and a longer lifetime under the best operating conditions. The developed data acquisition (DAQ) system can perform non-intrusive temperature measurements of each individual cell of an AC-PEFC stack of any power (from watts to kilowatts). The stack power is related to the temperature gradient; i.e., a higher power corresponds to a higher stack surface, and consequently higher temperature difference between the coldest and the hottest point. The developed DAQ system has been implemented with the low-cost open-source platform Arduino, and it is completed with a modular virtual instrument that has been developed using NI LabVIEW. Temperature vs time evolution of all the cells of an AC-PEFC both together and individually can be registered and supervised. The paper explains comprehensively the developed DAQ system together with experimental results that demonstrate the suitability of the system.

Future equivalent of 2010 Russian heatwave intensified by weakening soil moisture constraints

NASA Astrophysics Data System (ADS)

Rasmijn, L. M.; van der Schrier, G.; Bintanja, R.; Barkmeijer, J.; Sterl, A.; Hazeleger, W.

2018-05-01

The 2010 heatwave in eastern Europe and Russia ranks among the hottest events ever recorded in the region1,2. The excessive summer warmth was related to an anomalously widespread and intense quasi-stationary anticyclonic circulation anomaly over western Russia, reinforced by depletion of spring soil moisture1,3-5. At present, high soil moisture levels and strong surface evaporation generally tend to cap maximum summer temperatures6-8, but these constraints may weaken under future warming9,10. Here, we use a data assimilation technique in which future climate model simulations are nudged to realistically represent the persistence and strength of the 2010 blocked atmospheric flow. In the future, synoptically driven extreme warming under favourable large-scale atmospheric conditions will no longer be suppressed by abundant soil moisture, leading to a disproportional intensification of future heatwaves. This implies that future mid-latitude heatwaves analogous to the 2010 event will become even more extreme than previously thought, with temperature extremes increasing by 8.4 °C over western Russia. Thus, the socioeconomic impacts of future heatwaves will probably be amplified beyond current estimates.

Ultrabright continuously tunable terahertz-wave generation at room temperature

PubMed Central

Hayashi, Shin'ichiro; Nawata, Kouji; Taira, Takunori; Shikata, Jun-ichi; Kawase, Kodo; Minamide, Hiroaki

2014-01-01

The hottest frequency region in terms of research currently lies in the ‘frequency gap' region between microwaves and infrared: terahertz waves. Although new methods for generating terahertz radiation have been developed, most sources cannot generate high-brightness terahertz beams. Here we demonstrate the generation of ultrabright terahertz waves (brightness ~0.2 GW/sr·cm2, brightness temperature of ~1018 K, peak power of >50 kW) using parametric wavelength conversion in a nonlinear crystal; this is brighter than many specialized sources such as far-infrared free-electron lasers (~1016 K, ~2 kW). We revealed novel parametric wavelength conversion using stimulated Raman scattering in LiNbO3 without stimulated Brillouin scattering using recently-developed microchip laser. Furthermore, nonlinear up-conversion techniques allow the intense terahertz waves to be visualized and their frequency determined. These results are very promising for extending applied research into the terahertz region, and we expect that this source will open up new research fields such as nonlinear optics in the terahertz region. PMID:24898269

Ultrabright continuously tunable terahertz-wave generation at room temperature.

PubMed

Hayashi, Shin'ichiro; Nawata, Kouji; Taira, Takunori; Shikata, Jun-ichi; Kawase, Kodo; Minamide, Hiroaki

2014-06-05

The hottest frequency region in terms of research currently lies in the 'frequency gap' region between microwaves and infrared: terahertz waves. Although new methods for generating terahertz radiation have been developed, most sources cannot generate high-brightness terahertz beams. Here we demonstrate the generation of ultrabright terahertz waves (brightness ~0.2 GW/sr·cm(2), brightness temperature of ~10(18) K, peak power of >50 kW) using parametric wavelength conversion in a nonlinear crystal; this is brighter than many specialized sources such as far-infrared free-electron lasers (~10(16) K, ~2 kW). We revealed novel parametric wavelength conversion using stimulated Raman scattering in LiNbO3 without stimulated Brillouin scattering using recently-developed microchip laser. Furthermore, nonlinear up-conversion techniques allow the intense terahertz waves to be visualized and their frequency determined. These results are very promising for extending applied research into the terahertz region, and we expect that this source will open up new research fields such as nonlinear optics in the terahertz region.

The Top 10 Products

ERIC Educational Resources Information Center

American School & University, 2008

2008-01-01

In 2008, American School & University showcased some of the hottest products in the industry. This article presents the 10 most requested, as determined by readers. Products include fluorescent lighting, concrete floor maintenance and exterior sheathing.

Weird Warm Spot on Exoplanet

NASA Image and Video Library

2010-10-19

This frame from an animation based on NASA Spitzer Space Telescope data illustrates an unexpected warm spot on the surface of a gaseous exoplanet.The bright orange patches are the hottest part of the planet.

Death Valley, California

NASA Image and Video Library

2009-06-29

Death Valley, Calif., has the lowest point in North America, Badwater at 85.5 meters 282 feet below sea level. It is also the driest and hottest location in North America. This image is from NASA Terra spacecraft.

The effects of providing portable shade at pasture on dairy cow behavior and physiology.

PubMed

Palacio, S; Bergeron, R; Lachance, S; Vasseur, E

2015-09-01

Access to pasture has advantages for cows such as reduced lameness and improved udder health, but also may expose cows to stressors such as extreme heat. The objective of this study was to understand how portable shade affected physiological and behavioral responses of pastured dairy cows in a Canadian summer. Over 8wk, a total of 24 lactating Holstein cows were separated into 2 treatments, one with access to shade and a control without access to shade. The cows were pastured in groups of 4, with 3 field sections per treatment. Instantaneous scan sampling of behaviors (drinking, lying, grazing, other) performed in the shade or not were recorded every 5min for 3h/d during the hottest part of the day (peak hours: 1130-1530h) 3d/wk. Ambient temperature, humidity, and vaginal temperature were recorded at 10-min intervals. Daily milk production was also recorded. Differences between treatments by week were analyzed using the generalized linear mixed model with group as random effect and treatment as fixed effect. Cows with shade access were observed at the water trough up to 6.42 times less and lying down up to 1.75 times more. Cows with shade access grazed up to 1.5 times more but only when the temperature-humidity index was above their comfort threshold (≥72) during the hottest part of the day (wk 2). Cows sought shade when it was made available, but spent less than half of their time observed (%) in the shade (40.8±4.67) with the exception of wk 2 when most of the time was spent under the shade (74.3±4.77). Daily lying time was highest during peak hours for cows with shade access. However, no overall difference in total lying time between the 2 treatments was observed. No differences were found in vaginal temperature or milk production between treatments with the exception of wk 1 for daily milk production, which was higher for cows in the control treatment. In conclusion, cows sought shade when it was provided at pasture, whereas cows without access to shade seemed to alter their behavior to cope with heat stress, as seen from the lack of physiological differences between treatments. The results indicate that providing cows with access to pasture under a temperate climate does not seem to have any detrimental physiological or production effects and providing them with shade can potentially decrease production costs and help with water conservation strategies as fewer cows were observed at the water when shade was provided. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Staying cool in a changing landscape: the influence of maximum daily ambient temperature on grizzly bear habitat selection.

PubMed

Pigeon, Karine E; Cardinal, Etienne; Stenhouse, Gordon B; Côté, Steeve D

2016-08-01

To fulfill their needs, animals are constantly making trade-offs among limiting factors. Although there is growing evidence about the impact of ambient temperature on habitat selection in mammals, the role of environmental conditions and thermoregulation on apex predators is poorly understood. Our objective was to investigate the influence of ambient temperature on habitat selection patterns of grizzly bears in the managed landscape of Alberta, Canada. Grizzly bear habitat selection followed a daily and seasonal pattern that was influenced by ambient temperature, with adult males showing stronger responses than females to warm temperatures. Cutblocks aged 0-20 years provided an abundance of forage but were on average 6 °C warmer than mature conifer stands and 21- to 40-year-old cutblocks. When ambient temperatures increased, the relative change (odds ratio) in the probability of selection for 0- to 20-year-old cutblocks decreased during the hottest part of the day and increased during cooler periods, especially for males. Concurrently, the probability of selection for 21- to 40-year-old cutblocks increased on warmer days. Following plant phenology, the odds of selecting 0- to 20-year-old cutblocks also increased from early to late summer while the odds of selecting 21- to 40-year-old cutblocks decreased. Our results demonstrate that ambient temperatures, and therefore thermal requirements, play a significant role in habitat selection patterns and behaviour of grizzly bears. In a changing climate, large mammals may increasingly need to adjust spatial and temporal selection patterns in response to thermal constraints.

Thermal tolerance affects mutualist attendance in an ant-plant protection mutualism

PubMed Central

Fitzpatrick, Ginny; Lanan, Michele C.; Bronstein, Judith L.

2014-01-01

Mutualism is an often-complex interaction among multiple species, each of which may respond differently to abiotic conditions. The effects of temperature on the formation, dissolution, and success of these and other species interactions remain poorly understood. We studied the thermal ecology of the mutualism between the cactus Ferocactus wislizeni and its ant defenders (Forelius pruinosus, Crematogaster opuntiae, Solenopsis aurea, and Solenopsis xyloni) in the Sonoran Desert, USA. The ants are attracted to extrafloral nectar produced by the plants and in exchange protect the plants from herbivores; there is a hierarchy of mutualist effectiveness based on aggression toward herbivores. We determined the relationship between temperature and ant activity on plants, the thermal tolerance of each ant species, and ant activity in relation to the thermal environment of plants. Temperature played a role in determining which species interact as mutualists. Three of the four ant species abandoned the plants during the hottest part of the day (up to 40°C), returning when surface temperature began to decrease in the afternoon. The least effective ant mutualist, F. pruinosus, had a significantly higher critical thermal maximum than the other three species, was active across the entire range of plant surface temperatures observed (13.8-57.0°C), and visited plants that reached the highest temperatures. F. pruinosus occupied some plants full-time and invaded plants occupied by more dominant species when those species were thermally excluded. Combining data on thermal tolerance and mutualist effectiveness provides a potentially powerful tool for predicting the effects of temperature on mutualisms and mutualistic species. PMID:25012597

Do cities simulate climate change? A comparison of herbivore response to urban and global warming.

PubMed

Youngsteadt, Elsa; Dale, Adam G; Terando, Adam J; Dunn, Robert R; Frank, Steven D

2015-01-01

Cities experience elevated temperature, CO2 , and nitrogen deposition decades ahead of the global average, such that biological response to urbanization may predict response to future climate change. This hypothesis remains untested due to a lack of complementary urban and long-term observations. Here, we examine the response of an herbivore, the scale insect Melanaspis tenebricosa, to temperature in the context of an urban heat island, a series of historical temperature fluctuations, and recent climate warming. We survey M. tenebricosa on 55 urban street trees in Raleigh, NC, 342 herbarium specimens collected in the rural southeastern United States from 1895 to 2011, and at 20 rural forest sites represented by both modern (2013) and historical samples. We relate scale insect abundance to August temperatures and find that M. tenebricosa is most common in the hottest parts of the city, on historical specimens collected during warm time periods, and in present-day rural forests compared to the same sites when they were cooler. Scale insects reached their highest densities in the city, but abundance peaked at similar temperatures in urban and historical datasets and tracked temperature on a decadal scale. Although urban habitats are highly modified, species response to a key abiotic factor, temperature, was consistent across urban and rural-forest ecosystems. Cities may be an appropriate but underused system for developing and testing hypotheses about biological effects of climate change. Future work should test the applicability of this model to other groups of organisms. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

NASA Spacecraft Eyes Iceland Volcanic Eruption

NASA Image and Video Library

2014-09-03

On the night of Sept. 1, 2014, NASA Earth Observing 1 EO-1 spacecraft observed the ongoing eruption at Holuhraun, Iceland. This false-color image that emphasizes the hottest areas of the vent and resulting lava flows.

Present-day irrigation mitigates heat extremes

DOE PAGES

Thiery, Wim; Davin, Edouard L.; Lawrence, David M.; ...

2017-02-16

Irrigation is an essential practice for sustaining global food production and many regional economies. Emerging scientific evidence indicates that irrigation substantially affects mean climate conditions in different regions of the world. Yet how this practice influences climate extremes is currently unknown. Here we use ensemble simulations with the Community Earth System Model to assess the impacts of irrigation on climate extremes. An evaluation of the model performance reveals that irrigation has a small yet overall beneficial effect on the representation of present-day near-surface climate. While the influence of irrigation on annual mean temperatures is limited, we find a large impactmore » on temperature extremes, with a particularly strong cooling during the hottest day of the year (-0.78 K averaged over irrigated land). The strong influence on extremes stems from the timing of irrigation and its influence on land-atmosphere coupling strength. Together these effects result in asymmetric temperature responses, with a more pronounced cooling during hot and/or dry periods. The influence of irrigation is even more pronounced when considering subgrid-scale model output, suggesting that local effects of land management are far more important than previously thought. In conclusion, our results underline that irrigation has substantially reduced our exposure to hot temperature extremes in the past and highlight the need to account for irrigation in future climate projections.« less

Mammalian metabolic rates in the hottest fish on earth

PubMed Central

Wood, Chris M.; Brix, Kevin V.; De Boeck, Gudrun; Bergman, Harold L.; Bianchini, Adalto; Bianchini, Lucas F.; Maina, John N.; Johannsson, Ora E.; Kavembe, Geraldine D.; Papah, Michael B.; Letura, Kisipan M.; Ojoo, Rodi O.

2016-01-01

The Magadi tilapia, Alcolapia grahami, a small cichlid fish of Lake Magadi, Kenya lives in one of the most challenging aquatic environments on earth, characterized by very high alkalinity, unusual water chemistry, and extreme O2, ROS, and temperature regimes. In contrast to most fishes which live at temperatures substantially lower than the 36–40 °C of mammals and birds, an isolated population (South West Hot Springs, SWHS) of Magadi tilapia thrives in fast-flowing hotsprings with daytime highs of 43 °C and night-time lows of 32 °C. Another population (Fish Springs Lagoon, FSL) lives in a lagoon with fairly stable daily temperatures (33–36 °C). The upper critical temperatures (Ctmax) of both populations are very high; moreover the SWHS tilapia exhibit the highest Ctmax (45.6 °C) ever recorded for a fish. Routine rates of O2 consumption (MO2) measured on site, together with MO2 and swimming performance at 25, 32, and 39 °C in the laboratory, showed that the SWHS tilapia exhibited the greatest metabolic performance ever recorded in a fish. These rates were in the basal range of a small mammal of comparable size, and were all far higher than in the FSL fish. The SWHS tilapia represents a bellwether organism for global warming. PMID:27257105

Rainforest air-conditioning: the moderating influence of epiphytes on the microclimate in tropical tree crowns

NASA Astrophysics Data System (ADS)

Stuntz, Sabine; Simon, Ulrich; Zotz, Gerhard

2002-05-01

Epiphytes are often assumed to influence the microclimatic conditions of the tree crowns that they inhabit. In order to quantify this notion, we measured the parameters "temperature" (of the substrate surface and the boundary layer of air above it), "evaporative drying rate" and "evapotranspiration" at various locations within tree crowns with differing epiphyte assemblages. The host tree species was Annona glabra, which was either populated by one of three epiphyte species ( Dimerandra emarginata, Tillandsia fasciculata, or Vriesea sanguinolenta) or was epiphyte-free. We found that during the hottest and driest time of day, microsites in the immediate proximity of epiphytes had significantly lower temperatures than epiphyte-bare locations within the same tree crown, even though the latter were also shaded by host tree foliage or branches. Moreover, water loss through evaporative drying at microsites adjacent to epiphytes was almost 20% lower than at exposed microsites. We also found that, over the course of several weeks, the evapotranspiration in tree crowns bearing epiphytes was significantly lower than in trees without epiphytes. Although the influence of epiphytes on temperature extremes and evaporation rates is relatively subtle, their mitigating effect could be of importance for small animals like arthropods inhabiting an environment as harsh and extreme as the tropical forest canopy.

Morphological and phylogenetic diversity of thermophilic cyanobacteria in Algerian hot springs.

PubMed

Amarouche-Yala, Samia; Benouadah, Ali; El Ouahab Bentabet, Abd; López-García, Purificación

2014-11-01

Geothermal springs in Algeria have been known since the Roman Empire. They mainly locate in Eastern Algeria and are inhabited by thermophilic organisms, which include cyanobacteria forming mats and concretions. In this work, we have investigated the cyanobacterial diversity of these springs. Cyanobacteria were collected from water, concretions and mats in nine hot springs with water temperatures ranging from 39 to 93 °C. Samples were collected for isolation in culture, microscopic morphological examination, and molecular diversity analysis based on 16S rRNA gene sequences. Nineteen different cyanobacterial morphotypes were identified, the most abundant of which were three species of Leptolyngbya, accompanied by members of the genera Gloeocapsa, Gloeocapsopsis, Stigonema, Fischerella, Synechocystis, Microcoleus, Cyanobacterium, Chroococcus and Geitlerinema. Molecular diversity analyses were in good general agreement with classical identification and allowed the detection of additional species in three springs with temperatures higher than 50 °C. They corresponded to a Synechococcus clade and to relatives of the intracellularly calcifying Candidatus Gloeomargarita lithophora. The hottest springs were dominated by members of Leptolyngbya, Synechococcus-like cyanobacteria and Gloeomargarita, whereas Oscillatoriales other than Leptolyngbya, Chroococcales and Stigonematales dominated lower temperature springs. The isolation of some of these strains sets the ground for future studies on the biology of thermophilic cyanobacteria.

Spatial and temporal patterns of microclimates at an urban forest edge and their management implications.

PubMed

Li, Yingnan; Kang, Wanmo; Han, Yiwen; Song, Youngkeun

2018-01-23

Fragmented forests generate a variety of forest edges, leading to microclimates in the edge zones that differ from those in the forest interior. Understanding microclimatic variation is an important consideration for managers because it helps when making decisions about how to restrict the extent of edge effects. Thus, our study attempted to characterize the changing microclimate features at an urban forest edge located on Mt. Gwanak, Seoul, South Korea. We examined edge effects on air temperature, relative humidity, soil temperature, soil moisture, and photosynthetically active radiation (PAR) during the hottest three consecutive days in August 2016. Results showed that each variable responded differently to the edge effects. This urban forest edge had an effect on temporal changes at a diurnal scale in all microclimate variables, except soil moisture. In addition, all variables except relative humidity were significantly influenced by the edge effect up to 15 m inward from the forest boundary. The relative humidity fluctuated the most and showed the deepest extent of the edge effect. Moreover, the edge widths calculated from the relative humidity and air temperature both peaked in the late afternoon (16:00 h). Our findings provide a reference for forest managers in designing urban forest zones and will contribute to the conservation of fragmented forests in urban areas.

Properties of air-aluminum thermal plasmas

NASA Astrophysics Data System (ADS)

Cressault, Y.; Gleizes, A.; Riquel, G.

2012-07-01

We present the calculation and the main results of the properties of air-aluminum thermal plasmas, useful for complete modelling of arc systems involving aluminum contacts. The properties are calculated assuming thermal equilibrium and correspond to the equilibrium composition, thermodynamic functions, transport coefficients including diffusion coefficients and net emission coefficient representing the divergence of the radiative flux in the hottest plasma regions. The calculation is developed in the temperature range between 2000 and 30 000 K, for a pressure range from 0.1 to 1 bar and for several metal mass proportions. As in the case of other metals, the presence of aluminum vapours has a strong influence on three properties at intermediate temperatures: the electron number density, the electrical conductivity and the net emission coefficient. Some comparisons with other metal vapour (Cu, Fe and Ag) properties are made and show the original behaviour for Al-containing mixtures: mass density at high temperatures is low due to the low Al atomic mass; high electrical conductivity at T < 10 000 K due to low ionization potential (around 2 V less for Al than for the other metals); very strong self-absorption of ionized aluminum lines, leading to a net emission coefficient lower than that of pure air when T > 10 000 K, in contrast to copper or iron radiation.

Kinetics of liquid-mediated crystallization of amorphous Ge from multi-frame dynamic transmission electron microscopy

DOE PAGES

Santala, M. K.; Raoux, S.; Campbell, G. H.

2015-12-24

The kinetics of laser-induced, liquid-mediated crystallization of amorphous Ge thin films were studied using multi-frame dynamic transmission electron microscopy (DTEM), a nanosecond-scale photo-emission transmission electron microscopy technique. In these experiments, high temperature gradients are established in thin amorphous Ge films with a 12-ns laser pulse with a Gaussian spatial profile. The hottest region at the center of the laser spot crystallizes in ~100 ns and becomes nano-crystalline. Over the next several hundred nanoseconds crystallization continues radially outward from the nano-crystalline region forming elongated grains, some many microns long. The growth rate during the formation of these radial grains is measuredmore » with time-resolved imaging experiments. Crystal growth rates exceed 10 m/s, which are consistent with crystallization mediated by a very thin, undercooled transient liquid layer, rather than a purely solid-state transformation mechanism. The kinetics of this growth mode have been studied in detail under steady-state conditions, but here we provide a detailed study of liquid-mediated growth in high temperature gradients. Unexpectedly, the propagation rate of the crystallization front was observed to remain constant during this growth mode even when passing through large local temperature gradients, in stark contrast to other similar studies that suggested the growth rate changed dramatically. As a result, the high throughput of multi-frame DTEM provides gives a more complete picture of the role of temperature and temperature gradient on laser crystallization than previous DTEM experiments.« less

Statistical Analysis of Hubble /WFC3 Transit Spectroscopy of Extrasolar Planets

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

Fu, Guangwei; Deming, Drake; Knutson, Heather

2017-10-01

Transmission spectroscopy provides a window to study exoplanetary atmospheres, but that window is fogged by clouds and hazes. Clouds and haze introduce a degeneracy between the strength of gaseous absorption features and planetary physical parameters such as abundances. One way to break that degeneracy is via statistical studies. We collect all published HST /WFC3 transit spectra for 1.1–1.65 μ m water vapor absorption and perform a statistical study on potential correlations between the water absorption feature and planetary parameters. We fit the observed spectra with a template calculated for each planet using the Exo-transmit code. We express the magnitude ofmore » the water absorption in scale heights, thereby removing the known dependence on temperature, surface gravity, and mean molecular weight. We find that the absorption in scale heights has a positive baseline correlation with planetary equilibrium temperature; our hypothesis is that decreasing cloud condensation with increasing temperature is responsible for this baseline slope. However, the observed sample is also intrinsically degenerate in the sense that equilibrium temperature correlates with planetary mass. We compile the distribution of absorption in scale heights, and we find that this distribution is closer to log-normal than Gaussian. However, we also find that the distribution of equilibrium temperatures for the observed planets is similarly log-normal. This indicates that the absorption values are affected by observational bias, whereby observers have not yet targeted a sufficient sample of the hottest planets.« less

Kinetics of liquid-mediated crystallization of amorphous Ge from multi-frame dynamic transmission electron microscopy

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

Santala, M. K., E-mail: melissa.santala@oregonstate.edu; Campbell, G. H.; Raoux, S.

2015-12-21

The kinetics of laser-induced, liquid-mediated crystallization of amorphous Ge thin films were studied using multi-frame dynamic transmission electron microscopy (DTEM), a nanosecond-scale photo-emission transmission electron microscopy technique. In these experiments, high temperature gradients are established in thin amorphous Ge films with a 12-ns laser pulse with a Gaussian spatial profile. The hottest region at the center of the laser spot crystallizes in ∼100 ns and becomes nano-crystalline. Over the next several hundred nanoseconds crystallization continues radially outward from the nano-crystalline region forming elongated grains, some many microns long. The growth rate during the formation of these radial grains is measured withmore » time-resolved imaging experiments. Crystal growth rates exceed 10 m/s, which are consistent with crystallization mediated by a very thin, undercooled transient liquid layer, rather than a purely solid-state transformation mechanism. The kinetics of this growth mode have been studied in detail under steady-state conditions, but here we provide a detailed study of liquid-mediated growth in high temperature gradients. Unexpectedly, the propagation rate of the crystallization front was observed to remain constant during this growth mode even when passing through large local temperature gradients, in stark contrast to other similar studies that suggested the growth rate changed dramatically. The high throughput of multi-frame DTEM provides gives a more complete picture of the role of temperature and temperature gradient on laser crystallization than previous DTEM experiments.« less

Temperature controlled formation of lead/acid batteries

NASA Astrophysics Data System (ADS)

Bungardt, M.

At present, standard formation programs have to accommodate the worst case. This is important, especially in respect of variations in climatic conditions. The standard must be set so that during the hottest weather periods the maximum electrolyte temperature is not exceeded. As this value is defined not only by the desired properties and the recipe of the active mass, but also by type and size of the separators and by the dimensions of the plates, general rules cannot be formulated. It is considered to be advantageous to introduce limiting data for the maximum temperature into a general formation program. The latter is defined so that under normal to good ambient conditions the shortest formation time is achieved. If required, the temperature control will reduce the currents employed in the different steps, according to need, and will extend the formation time accordingly. With computer-controlled formation, these parameters can be readily adjusted to suit each type of battery and can also be reset according to modifications in the preceding processing steps. Such a procedure ensures that: (i) the formation time is minimum under the given ambient conditions; (ii) in the event of malpractice ( e.g. actual program not fitting to size) the batteries will not be destroyed; (iii) the energy consumption is minimized (note, high electrolyte temperature leads to excess gassing). These features are incorporated in the BA/FOS-500 battery formation system developed by Digatron. The operational characteristics of this system are listed in Table 1.

Statistical Analysis of Hubble/WFC3 Transit Spectroscopy of Extrasolar Planets

NASA Astrophysics Data System (ADS)

Fu, Guangwei; Deming, Drake; Knutson, Heather; Madhusudhan, Nikku; Mandell, Avi; Fraine, Jonathan

2018-01-01

Transmission spectroscopy provides a window to study exoplanetary atmospheres, but that window is fogged by clouds and hazes. Clouds and haze introduce a degeneracy between the strength of gaseous absorption features and planetary physical parameters such as abundances. One way to break that degeneracy is via statistical studies. We collect all published HST/WFC3 transit spectra for 1.1-1.65 micron water vapor absorption, and perform a statistical study on potential correlations between the water absorption feature and planetary parameters. We fit the observed spectra with a template calculated for each planet using the Exo-Transmit code. We express the magnitude of the water absorption in scale heights, thereby removing the known dependence on temperature, surface gravity, and mean molecular weight. We find that the absorption in scale heights has a positive baseline correlation with planetary equilibrium temperature; our hypothesis is that decreasing cloud condensation with increasing temperature is responsible for this baseline slope. However, the observed sample is also intrinsically degenerate in the sense that equilibrium temperature correlates with planetary mass. We compile the distribution of absorption in scale heights, and we find that this distribution is closer to log-normal than Gaussian. However, we also find that the distribution of equilibrium temperatures for the observed planets is similarly log-normal. This indicates that the absorption values are affected by observational bias, whereby observers have not yet targeted a sufficient sample of the hottest planets.

Statistical Analysis of Hubble/WFC3 Transit Spectroscopy of Extrasolar Planets

NASA Astrophysics Data System (ADS)

Fu, Guangwei; Deming, Drake; Knutson, Heather; Madhusudhan, Nikku; Mandell, Avi; Fraine, Jonathan

2017-10-01

Transmission spectroscopy provides a window to study exoplanetary atmospheres, but that window is fogged by clouds and hazes. Clouds and haze introduce a degeneracy between the strength of gaseous absorption features and planetary physical parameters such as abundances. One way to break that degeneracy is via statistical studies. We collect all published HST/WFC3 transit spectra for 1.1-1.65 μm water vapor absorption and perform a statistical study on potential correlations between the water absorption feature and planetary parameters. We fit the observed spectra with a template calculated for each planet using the Exo-transmit code. We express the magnitude of the water absorption in scale heights, thereby removing the known dependence on temperature, surface gravity, and mean molecular weight. We find that the absorption in scale heights has a positive baseline correlation with planetary equilibrium temperature; our hypothesis is that decreasing cloud condensation with increasing temperature is responsible for this baseline slope. However, the observed sample is also intrinsically degenerate in the sense that equilibrium temperature correlates with planetary mass. We compile the distribution of absorption in scale heights, and we find that this distribution is closer to log-normal than Gaussian. However, we also find that the distribution of equilibrium temperatures for the observed planets is similarly log-normal. This indicates that the absorption values are affected by observational bias, whereby observers have not yet targeted a sufficient sample of the hottest planets.

Cockle infection by Himasthla quissetensis - II. The theoretical effects of climate change

NASA Astrophysics Data System (ADS)

de Montaudouin, Xavier; Blanchet, Hugues; Desclaux-Marchand, Céline; Bazairi, Hocein; Alfeddy, Nazik; Bachelet, Guy

2016-07-01

Numerous marine populations experience parasite pressure. This is the case of the cockles Cerastoderma edule which are often highly infected by trematode macroparasites. These parasites display a complex life cycle, with a succession of free-living and parasitic stages. Climate, and in particular temperature, is an important modulator of the transmission dynamics of parasites. Consequently, global change is thought to have implications for the epidemiology of infectious diseases. Using Himasthla quissetensis, a dominant parasite of cockles as 2nd intermediate host in Arcachon Bay (France), we used mathematical models of parasite emergence (cercariae) and parasite infection (metacercariae) in cockles as a function of water temperature, in order to study different scenarios of temperature increases. Globally, with a + 0.5 °C to + 6.0 °C simulation, cumulated emergence of cercariae and accumulation of metacercariae tended to decrease or stagnate, respectively. This is the consequence of a trade-off between sooner (spring) and later (autumn) cercariae emergence/infestation on one hand, and a longer inhibition period of cercariae emergence/infestation during the hottest days in summer. Using sea water temperature in Oualidia (Morocco) where mean annual sea temperature is 3 °C higher than in Arcachon Bay, our model predicted infestation all year long (no seasonality). The model gave a correct estimation of the total number of parasites that was expected in cockles. Conversely, observed infestation in Oualidia followed a seasonal pattern like in Arcachon Bay. These results suggest that, if temperature is a strong driver of parasite transmission, extrapolation in the framework of climate change should be performed with caution.

FNLAC Meeting Showcases Frederick National Laboratory’s Achievements, Future Plans | Poster

Cancer.gov

Recent accomplishments and upcoming initiatives at the Frederick National Laboratory (FNL) were the hottest topics at the recent Frederick National Laboratory Advisory Committee (FNLAC) meeting. Here are some excerpts, accompanied by time stamps from the videocast.

Some Like It Hot.

ERIC Educational Resources Information Center

Brook, Richard; And Others

1997-01-01

Describes the Sonoran Desert, the hottest desert in North America. Discusses management challenges, recreation, exotic plants, threatened and endangered species, American Indian traditional cultural places, and riparian areas. Presents classroom activities aimed at educating youth about the area's many distinctive features and the importance of…

On the Unusually High Temperature of the Cluster of Galaxies 1E 0657-56

NASA Technical Reports Server (NTRS)

Yaqoob, Tahir

1999-01-01

A recent X-ray observation of the cluster 1E 0657-56 (z = 0.296) with ASC,4 implied an unusually high temperature of approx. 17 keV. Such a high temperature would make it the hottest known cluster and severely constrain cosmological models since, in a Universe with critical density (Omega = 1) the probability of observing such a cluster is only approx. 4 x 10(exp -5). Here we test the robustness of this observational result since it has such important implications. We analysed the data using a variety of different data analysis methods and spectral analysis assumptions and find a temperature of approx. 11 - 12 keV in all cases, except for one class of spectral fits. These are fits in which the absorbing column density is fixed at the Galactic value. Using simulated data for a 12 keV cluster, we show that a high temperature of approx. 17 keV is artificially obtained if the true spectrum has a stronger low-energy cut-off than that for Galactic absorption only. The apparent extra absorption may be astrophysical in origin, (either intrinsic or line-of-sight), or it may be a problem with the low-energy CCD efficiency. Although significantly lower than previous measurements, this temperature of kT approx. 11 - 12 keV is still relatively high since only a few clusters have been found to have temperatures higher than 10 keV and the data therefore still present some difficulty for an Omega = 1 Universe. Our results will also be useful to anyone who wants to estimate the systematic errors involved in different methods of background subtraction of ASCA data for sources with similar signal-to-noise to that of the IE 0657-56 data reported here.

Behavioural adaptations of birds to environments where evaporation is high and water is in short supply.

PubMed

Davies, S J

1982-01-01

1. Behaviour that reduces the heat load or evaporation experienced by birds living in arid areas is reviewed. Many species have evolved hunting behaviour that enables them to remain inactive during the hottest parts of the day and thus greatly reduce the amount of metabolic heat that they need to dissipate. Flights to water are made at low ambient temperatures, either early in the morning or late in the evening. Fighting is rare in many species of desert birds, avoiding the excess generation of heat by this activity. Many arid zone birds maintain long-lasting pair bonds, avoiding the necessity for active, elaborate display before breeding and again reducing activity. 2. The observations on nomadism are discussed. No unifying principles that might control the behaviour of birds seeking widely separated areas of abundance of food have yet emerged. 3. Some species have evolved mechanisms, embodied in behavioural characteristics, that ensure that the eggs and chicks are sheltered from high temperatures and are provided with adequate moisture. 4. Birds have evolved many different kinds of behavioural adaptation to arid zones and representatives from many avian families live there, apparently successfully.

The hottest planet.

PubMed

Harrington, Joseph; Luszcz, Statia; Seager, Sara; Deming, Drake; Richardson, L Jeremy

2007-06-07

Of the over 200 known extrasolar planets, just 14 pass in front of and behind their parent stars as seen from Earth. This fortuitous geometry allows direct determination of many planetary properties. Previous reports of planetary thermal emission give fluxes that are roughly consistent with predictions based on thermal equilibrium with the planets' received radiation, assuming a Bond albedo of approximately 0.3. Here we report direct detection of thermal emission from the smallest known transiting planet, HD 149026b, that indicates a brightness temperature (an expression of flux) of 2,300 +/- 200 K at 8 microm. The planet's predicted temperature for uniform, spherical, blackbody emission and zero albedo (unprecedented for planets) is 1,741 K. As models with non-zero albedo are cooler, this essentially eliminates uniform blackbody models, and may also require an albedo lower than any measured for a planet, very strong 8 microm emission, strong temporal variability, or a heat source other than stellar radiation. On the other hand, an instantaneous re-emission blackbody model, in which each patch of surface area instantly re-emits all received light, matches the data. This planet is known to be enriched in heavy elements, which may give rise to novel atmospheric properties yet to be investigated.

Geochemistry of volcanic gas from Avachinsky volcano (Kamchatka, Russia)

NASA Astrophysics Data System (ADS)

Chaplygin, Ilya; Taran, Yuri; Lavrushin, Vasily; Inguaggiato, Salvatore

2015-04-01

Among 29 active volcanoes on Kamchatka Avachinsky volcano (2741 m) attracts more attention that others due to its proximity (25 km) to Petropavlovsk-Kamchatsky, the biggest city on Kamchatka. The last eruption at Avacha occurred in summit crater in January 1991. It produced small lava flow and left lava plug, which cracked in 2001. Gas emissions from the crack and fumarolic sites at Avachinsky has been monitored from 1994 (Malik, Zelensky, 2014). Previous data show that gas temperature increase (T°C): 473 (09.94), 416 (08.97), 400 (08.99), 500 (10.01), 626 (09.13). We present chemical and isotopic data on gas and condensate samples taken from the hottest fumarole at Avacha (630°C) in July 2014 (mol.%): H2O 96.46, CO2 1.55, SO2 1.32, HCl 0.27, HF 0.02, H2 0.28; δ18O 2.28‰, δD -48.8‰. According to data available gas from Avacha is close to magmatic fluid of subduction zone volcanoes. ICP data on condensate collected allow to intercompare metal-bearing capacity of high-temperature gases from Avacha, Gorely, Tolbachik and Kudriavy volcanoes. The study is supported by RFBR, grant 14-05-00874.

Human contribution to the European heatwave of 2003

NASA Astrophysics Data System (ADS)

Stott, Peter A.; Stone, D. A.; Allen, M. R.

2004-12-01

The summer of 2003 was probably the hottest in Europe since at latest AD 1500, and unusually large numbers of heat-related deaths were reported in France, Germany and Italy. It is an ill-posed question whether the 2003 heatwave was caused, in a simple deterministic sense, by a modification of the external influences on climate-for example, increasing concentrations of greenhouse gases in the atmosphere-because almost any such weather event might have occurred by chance in an unmodified climate. However, it is possible to estimate by how much human activities may have increased the risk of the occurrence of such a heatwave. Here we use this conceptual framework to estimate the contribution of human-induced increases in atmospheric concentrations of greenhouse gases and other pollutants to the risk of the occurrence of unusually high mean summer temperatures throughout a large region of continental Europe. Using a threshold for mean summer temperature that was exceeded in 2003, but in no other year since the start of the instrumental record in 1851, we estimate it is very likely (confidence level >90%) that human influence has at least doubled the risk of a heatwave exceeding this threshold magnitude.

Genetic variability for stomatal conductance in Pima cotton and its relation to improvements of heat adaptation.

PubMed Central

Radin, J W; Lu, Z; Percy, R G; Zeiger, E

1994-01-01

Responses of stomata to environment have been intensively studied, but little is known of genetic effects on stomatal conductance or their consequences. In Pima cotton (Gossypium barbadense L.), a crop that is bred for irrigated production in very hot environments, stomatal conductance varies genetically over a wide range and has increased with each release of new higher-yielding cultivars. A cross between heat-adapted (high-yielding) and unadapted genotypes produced F2 progeny cosegregating for stomatal conductance and leaf temperature. Within segregating populations in the field, conductance was negatively correlated with foliar temperature because of evaporative cooling. Plants were selected from the F2 generation specifically and solely for differing stomatal conductance. Among F3 and F4 populations derived from these selections, conductance and leaf cooling were significantly correlated with fruiting prolificacy during the hottest period of the year and with yield. Conductance was not associated with other factors that might have affected yield potential (single-leaf photosynthetic rate, leaf water potential). As breeders have increased the yield of this crop, genetic variability for conductance has allowed inadvertent selection for "heat avoidance" (evaporative cooling) in a hot environment. PMID:11607487

Wireless Technician

ERIC Educational Resources Information Center

Tech Directions, 2011

2011-01-01

One of the hottest areas in technology is invisible. Wireless communications allow people to transmit voice messages, data, and other signals through the air without physically connecting senders to receivers with cables or wires. And the technology is spreading at lightning speed. Cellular phones, personal digital assistants, and wireless…

Update of S-NPP VIIRS Thermal Emissive Bands Radiometric Calibration Stability Monitoring Using the Moon

NASA Technical Reports Server (NTRS)

Wang, Zhipeng; Xiong, Xiaoxiong; Li, Yonghong

2016-01-01

The Suomi-NPP VIIRS thermal emissive bands (TEB) are radiometrically calibrated on-orbit with reference to an onboard blackbody (BB) regularly operated at approximately 292.5 K. The calibration stability at other temperature ranges can be evaluated based on the observations of remote targets with stable thermal properties, such as the Moon. VIIRS has scheduled viewings of the Moon on a nearly monthly basis at a phase angle of nearly -51 degrees. In this study, the brightness temperatures (BT) of the lunar surface retrieved using the detector gain coefficients calibrated with the BB are trended to monitor the calibration stability of VIIRS TEB. Since the Lunar surface temperatures are spatially non-uniform and vary greatly with the photometric geometry, the BT trending must be based on the same regions of the Moon under the same solar illumination condition. Also, the TEB lunar images are always partially saturated because the highest lunar surface temperatures are beyond the dynamic range of all VIIRS TEB detectors. Therefore, a temporally invariant dynamic mask is designed to clip a fraction of the lunar images corresponding to the regions of the Moon that may saturate the detector at any lunar event. The BT of the remaining hottest pixels are then trended. Results show that, since the launch of VIIRS to mid-2016, the radiometric calibration of all TEB detectors has been stable within 0.4 K at the BT range of as high as 350 K.

Transitions in the Cloud Composition of Hot Jupiters

NASA Astrophysics Data System (ADS)

Parmentier, Vivien; Fortney, Jonathan J.; Showman, Adam P.; Morley, Caroline; Marley, Mark S.

2016-09-01

Over a large range of equilibrium temperatures, clouds shape the transmission spectrum of hot Jupiter atmospheres, yet their composition remains unknown. Recent observations show that the Kepler light curves of some hot Jupiters are asymmetric: for the hottest planets, the light curve peaks before secondary eclipse, whereas for planets cooler than ˜1900 K, it peaks after secondary eclipse. We use the thermal structure from 3D global circulation models to determine the expected cloud distribution and Kepler light curves of hot Jupiters. We demonstrate that the change from an optical light curve dominated by thermal emission to one dominated by scattering (reflection) naturally explains the observed trend from negative to positive offset. For the cool planets the presence of an asymmetry in the Kepler light curve is a telltale sign of the cloud composition, because each cloud species can produce an offset only over a narrow range of effective temperatures. By comparing our models and the observations, we show that the cloud composition of hot Jupiters likely varies with equilibrium temperature. We suggest that a transition occurs between silicate and manganese sulfide clouds at a temperature near 1600 K, analogous to the L/T transition on brown dwarfs. The cold trapping of cloud species below the photosphere naturally produces such a transition and predicts similar transitions for other condensates, including TiO. We predict that most hot Jupiters should have cloudy nightsides, that partial cloudiness should be common at the limb, and that the dayside hot spot should often be cloud-free.

Investigating the Temperature Problem in Narrow Line Emitting AGN

NASA Astrophysics Data System (ADS)

Jenkins, Sam; Richardson, Chris T.

2018-06-01

Our research investigates the physical conditions in gas clouds around the narrow line region of AGN. Specifically, we explore the necessary conditions for anomalously high electron temperatures, Te, in those clouds. Our 321 galaxy data set was acquired from SDSS DR14 after requiring S/N > 5.0 in [OIII] 4363 and S/N > 3.0 in all BPT diagram emission lines, to ensure both accurate Te and galaxy classification, with 0.04 < z < 1.0. Interestingly, our data set contained no LINERs. We ran simulations using the simulation code Cloudy, and focused on matching the emission exhibited by the hottest of the 70 AGN in our data set. We used multicore computing to cut down on run time, which drastically improved the efficiency of our simulations. We varied hydrogen density, ionization parameter, and metallicity, Z, only to find these three parameters alone were incapable of recreating anomalously high Te, but successfully matched galaxies showing low- to moderate Te. These highest temperature simulations were at low Z, and were able to facilitate higher temperatures because they avoided the cooling effects of high Z. Our most successful simulations varied Z and grain content, which matched approximately 10% of our high temperature data. Our simulations with the highest grain content produced the highest Te because of the photoelectric heating effect that grains provide, which we confirmed by monitoring each heating mechanism as a function of depth. In the near future, we plan to run simulations varying grain content and ionization parameter in order to study the effects these conditions have on gas cloud Te.

A Matter of Life or Death: Untangling the Coupled Roles of Behavior, Microclimate and Physiological Polymorphism in Governing Vulnerability of Intertidal Snails to Heat Stress

NASA Astrophysics Data System (ADS)

Dong, Y.; Li, X.; Choi, F.; Willams, G.; Somero, G. N.; Helmuth, B.

2016-12-01

Changing patterns of species' biogeographic distributions are driven by cumulative effects of much smaller scale processes. Specifically, vulnerability of animals to thermal stress is the result of physiological sensitivities to body temperature (Tb), local microclimatic conditions, and abilities to anticipate extreme conditions and move to cooler refugia. These variables have rarely been quantified simultaneously over large geographic scales. We analyzed the thermal tolerances of three species of rocky intertidal snails from eight sites spanning 11.5 degrees of latitude along the Chinese coast. Using a biophysical model, we estimated potential Tb in sun-exposed and shaded microhabitats for all species at these sites for 30 years. We then compared maximum predicted Tb against the temperatures at which cardiac function was impaired (Arrhenius Break Temperatures, ABT) and lethal limits were reached (cardiac Flat Line Temperatures, FLT) to calculate thermal Safety Margins (TSM) for normal physiological function (TSMABT) and heat death (TSMFLT). Regular exceedance of FLT in sun-exposed microhabitats was predicted for only one site in the middle of the geographic gradient. However, ABT was exceeded at sun-exposed microhabitats in most sites, suggesting significant physiological impairment for snails that fail to move into the shade. An autocorrelation analysis of snail Tb showed that predictability of extreme temperatures was lowest at the hottest sites, an indication that reliance on behavioral thermoregulation may be a risky strategy. Observed large differences in ABT and FLT among conspecifics emphasize the critical role of physiological polymorphisms in governing the vulnerability of populations to heat stress.

NEXT Ion Thruster Thermal Model

NASA Technical Reports Server (NTRS)

VanNoord, Jonathan L.

2010-01-01

As the NEXT ion thruster progresses towards higher technology readiness, it is necessary to develop the tools that will support its implementation into flight programs. An ion thruster thermal model has been developed for the latest prototype model design to aid in predicting thruster temperatures for various missions. This model is comprised of two parts. The first part predicts the heating from the discharge plasma for various throttling points based on a discharge chamber plasma model. This model shows, as expected, that the internal heating is strongly correlated with the discharge power. Typically, the internal plasma heating increases with beam current and decreases slightly with beam voltage. The second is a model based on a finite difference thermal code used to predict the thruster temperatures. Both parts of the model will be described in this paper. This model has been correlated with a thermal development test on the NEXT Prototype Model 1 thruster with most predicted component temperatures within 5 to 10 C of test temperatures. The model indicates that heating, and hence current collection, is not based purely on the footprint of the magnet rings, but follows a 0.1:1:2:1 ratio for the cathode-to-conical-to-cylindrical-to-front magnet rings. This thermal model has also been used to predict the temperatures during the worst case mission profile that is anticipated for the thruster. The model predicts ample thermal margin for all of its components except the external cable harness under the hottest anticipated mission scenario. The external cable harness will be re-rated or replaced to meet the predicted environment.

NIMS: Hotspots on Io During G2

NASA Image and Video Library

1998-03-26

The Near Infrared Mapping Spectrometer (NIMS) on the Galileo spacecraft imaged Io at high spectral resolution at a range of 439,000 km (275,000 miles) during the G2 encounter on 7 September 1996. This image shows (on the right) Io as seen in the infrared by NIMS. The image on the left shows the same view from Voyager in 1979. This NIMS image can be compared to the NIMS images from the G1 orbit (June 1996) to monitor changes on Io. The NIMS image is at 4.9 microns, showing thermal emissions from the hotspots. The brightness of the pixels is a function of size and temperature. At least 10 hotspots have been identified and can be matched with surface features. An accurate determination of the position of the hotspot in the vicinity of Shamash Patera is pending. Hotspots are seen in the vicinity of Prometheus, Volund and Marduk, all sites of volcanic plume activity during the Galileo encounters, and also of active plumes in 1979. Temperatures and areas have been calculated for the hotspots shown. Temperatures range from 828 K (1031 F) to 210 K (- 81.4 F). The lowest temperature is significantly higher than the Io background (non-hotspot) surface temperature of about 100 K (-279 F). Hotspot areas range from 6.5 square km (2.5 sq miles) to 40,000 sq km (15,400 sq miles). The hottest hotspots have smallest areas, and the cooler hotspots have the largest areas. NIMS is continuing to observe Io to monitor volcanic activity throughout the Galileo mission. http://photojournal.jpl.nasa.gov/catalog/PIA00520

Thermal monitoring of hydrothermal activity by permanent infrared automatic stations: Results obtained at Solfatara di Pozzuoli, Campi Flegrei (Italy)

NASA Astrophysics Data System (ADS)

Chiodini, G.; Vilardo, G.; Augusti, V.; Granieri, D.; Caliro, S.; Minopoli, C.; Terranova, C.

2007-12-01

A permanent automatic infrared (IR) station was installed at Solfatara crater, the most active zone of Campi Flegrei caldera. After a positive in situ calibration of the IR camera, we analyze 2175 thermal IR images of the same scene from 2004 to 2007. The scene includes a portion of the steam heated hot soils of Solfatara. The experiment was initiated to detect and quantify temperature changes of the shallow thermal structure of a quiescent volcano such as Solfatara over long periods. Ambient temperature is the main parameter affecting IR temperatures, while air humidity and rain control image quality. A geometric correction of the images was necessary to remove the effects of slow movement of the camera. After a suitable correction the images give a reliable and detailed picture of the temperature changes, over the period October 2004 to January 2007, which suggests that origin of the changes were linked to anthropogenic activity, vegetation growth, and the increase of the flux of hydrothermal fluids in the area of the hottest fumaroles. Two positive temperature anomalies were registered after the occurrence of two seismic swarms which affected the hydrothermal system of Solfatara in October 2005 and October 2006. It is worth noting that these signs were detected in a system characterized by a low level of activity with respect to systems affected by real volcanic crisis where more spectacular results will be expected. Results of the experiment show that this kind of monitoring system can be a suitable tool for volcanic surveillance.

Seasonal temperature acclimatization in a semi-fossorial mammal and the role of burrows as thermal refuges

PubMed Central

Rachlow, Janet L.; Chappell, Mark A.; Camp, Meghan J.; Johnson, Timothy R.; Shipley, Lisa A.; Paul, David R.; Forbey, Jennifer S.

2018-01-01

Small mammals in habitats with strong seasonal variation in the thermal environment often exhibit physiological and behavioral adaptations for coping with thermal extremes and reducing thermoregulatory costs. Burrows are especially important for providing thermal refuge when above-ground temperatures require high regulatory costs (e.g., water or energy) or exceed the physiological tolerances of an organism. Our objective was to explore the role of burrows as thermal refuges for a small endotherm, the pygmy rabbit (Brachylagus idahoensis), during the summer and winter by quantifying energetic costs associated with resting above and below ground. We used indirect calorimetry to determine the relationship between energy expenditure and ambient temperature over a range of temperatures that pygmy rabbits experience in their natural habitat. We also measured the temperature of above- and below-ground rest sites used by pygmy rabbits in eastern Idaho, USA, during summer and winter and estimated the seasonal thermoregulatory costs of resting in the two microsites. Although pygmy rabbits demonstrated seasonal physiological acclimatization, the burrow was an important thermal refuge, especially in winter. Thermoregulatory costs were lower inside the burrow than in above-ground rest sites for more than 50% of the winter season. In contrast, thermal heterogeneity provided by above-ground rest sites during summer reduced the role of burrows as a thermal refuge during all but the hottest periods of the afternoon. Our findings contribute to an understanding of the ecology of small mammals in seasonal environments and demonstrate the importance of burrows as thermal refuge for pygmy rabbits. PMID:29576977

Numerical investigation of flow and heat transfer in a novel configuration multi-tubular fixed bed reactor for propylene to acrolein process

NASA Astrophysics Data System (ADS)

Jiang, Bin; Hao, Li; Zhang, Luhong; Sun, Yongli; Xiao, Xiaoming

2015-01-01

In the present contribution, a numerical study of fluid flow and heat transfer performance in a pilot-scale multi-tubular fixed bed reactor for propylene to acrolein oxidation reaction is presented using computational fluid dynamics (CFD) method. Firstly, a two-dimensional CFD model is developed to simulate flow behaviors, catalytic oxidation reaction, heat and mass transfer adopting porous medium model on tube side to achieve the temperature distribution and investigate the effect of operation parameters on hot spot temperature. Secondly, based on the conclusions of tube-side, a novel configuration multi-tubular fixed-bed reactor comprising 790 tubes design with disk-and-doughnut baffles is proposed by comparing with segmental baffles reactor and their performance of fluid flow and heat transfer is analyzed to ensure the uniformity condition using molten salt as heat carrier medium on shell-side by three-dimensional CFD method. The results reveal that comprehensive performance of the reactor with disk-and-doughnut baffles is better than that of with segmental baffles. Finally, the effects of operating conditions to control the hot spots are investigated. The results show that the flow velocity range about 0.65 m/s is applicable and the co-current cooling system flow direction is better than counter-current flow to control the hottest temperature.

ASTRONOMY: Neighborhood Gamma Ray Burst Boosts Theory.

PubMed

Schilling, G

2000-07-07

Titanic explosions that emit powerful flashes of energetic gamma rays are one of astronomy's hottest mysteries. Now an analysis of the nearest gamma ray burst yet detected has added weight to the popular theory that they are expelled during the death throes of supermassive stars.

Control Freak

ERIC Educational Resources Information Center

Waters, John K.

2007-01-01

The hottest technology trends in higher education today can be boiled down to two roughly converse capabilities: the delivery of time- and space-shifted instruction to individual students (think podcasts), and the coordination of disparate-source content within the classroom, for enriched group experiences. The first is taking advantage of…

Hourly associations between heat and ambulance calls.

PubMed

Guo, Yuming

2017-01-01

The response speed of ambulance calls is very crucial to rescue patients suffering immediately life threatening conditions. The serious health outcomes might be caused by exposing to extreme heat only several hours before. However, limited evidence is available on this topic. This study aims to examine the hourly association between heat and ambulance calls, to improve the ambulance services and to better protect health. Hourly data on ambulance calls for non-accidental causes, temperature and air pollutants (PM 10 , NO 2 , and O 3 ) were collected from Brisbane, Australia, during 2001 and 2007. A time-stratified case-crossover design was used to examine the associations between hourly ambulance calls and temperature during warm season (Nov, Dec, Jan, Feb, and Mar), while adjusting for potential confounders. Stratified analyses were performed for sex and age groups. Ambulance calls peaked at 10am for all groups, except those aged <15 years at 19pm, while temperature was hottest at 13pm. The hourly heat-ambulance calls relationships were non-linear for all groups, with thresholds between 27 °C and 31 °C. The associations appeared immediately, and lasted for about 24 h. There were no significant modification effect by sex and age. The findings suggest that hot hourly temperatures (>27 °C) increase the demands of ambulance. This information is helpful to increase the efficiency of ambulance service then save lives, for example, preparing more ambulance before appearance of extremely hot temperature in combination with weather forecast. Also, people should better arrange their time for outdoor activities to avoid exposing to extreme hot temperatures. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fog as an ecosystem service: Quantifying fog-mediated reductions in maximum temperature across coastal to inland transects in northern California

NASA Astrophysics Data System (ADS)

Torregrosa, A.; Flint, L. E.; Flint, A. L.; Combs, C.; Peters, J.

2013-12-01

Several studies have documented the human benefits of temperature cooling derived from coastal fog such as the reduction in the number of hospital visits/emergency response requests from heat stress-vulnerable population sectors or decreased energy consumption during periods when summer maximum temperatures are lower than normal. In this study we quantify the hourly, daily, monthly and seasonal thermal effect of fog and low clouds (FLC) hours on maximum summer temperatures across a northern California landscape. The FLC data summaries are calculated from the CIRA (Cooperative Institute for Research in the Atmosphere) 10 year archive that were derived from hourly night and day images using channels 1 (Visible), 2 (3.6 μm) and 4 (10.7 μm) NOAA GOES (Geostationary Operational Environmental Satellite). The FLC summaries were analyzed with two sets of site based data, meteorological (met) station-based measurements and downscaled interpolated PRISM data for selected point locations spanning a range of coastal to inland geographic conditions and met station locations. In addition to finding a 0.4 degree C per hour of FLC effect, our results suggest variability related to site specific thermal response. For example, sites closest to the coast have less thermal variability between low cloud and sunny days than sites further from the coast suggesting a much stronger influence of ocean temperature than of FLC thermal dynamics. The thermal relief provided by summertime FLC is equivalent in magnitude to the temperature increase projected by the driest and hottest of regional downscaled climate models using the A2 ('worst') IPCC scenario. Extrapolating these thermal calculations can facilitate future quantifications of the ecosystem service provided by summertime low clouds and fog.

Effect of four different reflective barriers on black-globe temperatures in calf hutches

NASA Astrophysics Data System (ADS)

Friend, T. H.; Haberman, J. A.; Binion, W. R.

2014-12-01

Polyethylene hutches are a popular method of housing dairy calves from 0 to 60 or more days of age, although these hutches get hot when in full sun. This study characterized the relative differences in the ability of four different types of radiant barriers to reduce black-globe temperature within these hutches. Treatments included three different types of covers (two types of laminates (Cadpak P and Cadpak ESD) and an aluminized 3.0-mil white low-density polyethylene (LDPE)) and a reflective paint (LO/MIT-1). The reflective covers were 1.8 × 3 m finished size, and covered the top and sides of the hutch down to 0.15 m above the ground, leaving the front and back exposed. The LO/MIT-1 paint covered the entire sides and roof of the hutch. Two 24-h trials 1 week apart were conducted during relatively hot and clear days in early August. Black-globe temperatures were recorded in duplicate and averaged at 20-min intervals using blackened table tennis balls mounted 0.3 m above the floor in the center of each hutch. Ambient temperature (shade) during the hottest 2-h period for both trials averaged 39.9 °C while the uncovered control averaged 41.1 °C, and LO/MIT-1 averaged 39.9 °C; both of which were significantly higher ( P < 0.01) than the Cadpak P (38.9 °C), Cadpak ESD (38.6 °C), and aluminized LDPE (38.7 °C). During periods of high solar radiation, the hutches with covers had lowest black-globe temperatures followed by hutches painted with reflective paint, while control hutches had the highest temperature.

Individual differences in normal body temperature: longitudinal big data analysis of patient records.

PubMed

Obermeyer, Ziad; Samra, Jasmeet K; Mullainathan, Sendhil

2017-12-13

To estimate individual level body temperature and to correlate it with other measures of physiology and health. Observational cohort study. Outpatient clinics of a large academic hospital, 2009-14. 35 488 patients who neither received a diagnosis for infections nor were prescribed antibiotics, in whom temperature was expected to be within normal limits. Baseline temperatures at individual level, estimated using random effects regression and controlling for ambient conditions at the time of measurement, body site, and time factors. Baseline temperatures were correlated with demographics, medical comorbidities, vital signs, and subsequent one year mortality. In a diverse cohort of 35 488 patients (mean age 52.9 years, 64% women, 41% non-white race) with 243 506 temperature measurements, mean temperature was 36.6°C (95% range 35.7-37.3°C, 99% range 35.3-37.7°C). Several demographic factors were linked to individual level temperature, with older people the coolest (-0.021°C for every decade, P<0.001) and African-American women the hottest (versus white men: 0.052°C, P<0.001). Several comorbidities were linked to lower temperature (eg, hypothyroidism: -0.013°C, P=0.01) or higher temperature (eg, cancer: 0.020, P<0.001), as were physiological measurements (eg, body mass index: 0.002 per m/kg 2 , P<0.001). Overall, measured factors collectively explained only 8.2% of individual temperature variation. Despite this, unexplained temperature variation was a significant predictor of subsequent mortality: controlling for all measured factors, an increase of 0.149°C (1 SD of individual temperature in the data) was linked to 8.4% higher one year mortality (P=0.014). Individuals' baseline temperatures showed meaningful variation that was not due solely to measurement error or environmental factors. Baseline temperatures correlated with demographics, comorbid conditions, and physiology, but these factors explained only a small part of individual temperature variation. Unexplained variation in baseline temperature, however, strongly predicted mortality. 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.

Individual differences in normal body temperature: longitudinal big data analysis of patient records

PubMed Central

Samra, Jasmeet K; Mullainathan, Sendhil

2017-01-01

Abstract Objective To estimate individual level body temperature and to correlate it with other measures of physiology and health. Design Observational cohort study. Setting Outpatient clinics of a large academic hospital, 2009-14. Participants 35 488 patients who neither received a diagnosis for infections nor were prescribed antibiotics, in whom temperature was expected to be within normal limits. Main outcome measures Baseline temperatures at individual level, estimated using random effects regression and controlling for ambient conditions at the time of measurement, body site, and time factors. Baseline temperatures were correlated with demographics, medical comorbidities, vital signs, and subsequent one year mortality. Results In a diverse cohort of 35 488 patients (mean age 52.9 years, 64% women, 41% non-white race) with 243 506 temperature measurements, mean temperature was 36.6°C (95% range 35.7-37.3°C, 99% range 35.3-37.7°C). Several demographic factors were linked to individual level temperature, with older people the coolest (–0.021°C for every decade, P<0.001) and African-American women the hottest (versus white men: 0.052°C, P<0.001). Several comorbidities were linked to lower temperature (eg, hypothyroidism: –0.013°C, P=0.01) or higher temperature (eg, cancer: 0.020, P<0.001), as were physiological measurements (eg, body mass index: 0.002 per m/kg2, P<0.001). Overall, measured factors collectively explained only 8.2% of individual temperature variation. Despite this, unexplained temperature variation was a significant predictor of subsequent mortality: controlling for all measured factors, an increase of 0.149°C (1 SD of individual temperature in the data) was linked to 8.4% higher one year mortality (P=0.014). Conclusions Individuals’ baseline temperatures showed meaningful variation that was not due solely to measurement error or environmental factors. Baseline temperatures correlated with demographics, comorbid conditions, and physiology, but these factors explained only a small part of individual temperature variation. Unexplained variation in baseline temperature, however, strongly predicted mortality. PMID:29237616

School-Based Management: Theory and Practice.

ERIC Educational Resources Information Center

George, Patricia, Ed.; Potter, Eugenia Cooper, Ed.

School-based management (SBM), sometimes called site-based management, is fast becoming the hottest restructuring item in the arsenal of reformers, teachers' unions, governors, and legislators who want to change the traditional ways in which schools and school districts do business. This document comprises three main sections with contributions…

The 10 Hottest Technologies in Telecom.

ERIC Educational Resources Information Center

Flanagan, Patrick

1996-01-01

Synthesizes opinions of experts regarding technologies deemed most likely to enter the telecommunications mainstream by 1998, including: (1) the Java programming language; (2) voice- over frame relay; (3) virtual local area networks (LANs); (4) cable modems; (5) gigabit LANs; (6) Internet appliances; (7) personal satellite phones; (8) intranets;…

Brain Training Draws Questions about Benefits

ERIC Educational Resources Information Center

Sparks, Sarah D.

2012-01-01

While programs to improve students' working memory are among the hottest new education interventions, new studies are calling into question whether exercises to improve this foundational skill can actually translate into greater intelligence, problem-solving ability, or academic achievement. Working memory is the system the mind uses to hold…

Suueeet Kickin' ... Suueeet Sweatin'

ERIC Educational Resources Information Center

Clevenger, Karen

2005-01-01

This article focuses on cardio-kickboxing, one of the hottest fitness trends sweeping the nation's fitness centers. The activity moves beyond the basics of kickboxing and provides participants with skills and techniques that help to enhance form, speed, power, and balance. Cardio-kickboxing is fun because it deviates from more conventional…

Kepler Supernova Remnant: A View from Chandra X-Ray Observatory

NASA Image and Video Library

2004-10-06

The images indicate that the bubble of gas that makes up the supernova remnant appears different in various types of light. Chandra reveals the hottest gas [colored blue and colored green], which radiates in X-rays. http://photojournal.jpl.nasa.gov/catalog/PIA06908

Thermodynamics of the Solar Corona and Evolution of the Solar Magnetic Field as Inferred from the Total Solar Eclipse Observations of 11 July 2010

NASA Technical Reports Server (NTRS)

Habbal, Shadia Rifai; Druckmueller, Miloslav; Morgan, Huw; Ding, Adalbert; Johnson, Judd; Druckmuellerova, Hana; Daw, Adrian; Arndt, Martina B.; Dietzel, Martin; Saken, Jon

2011-01-01

We report on multi-wavelength observations of the corona taken simultaneously in broadband white light, and in seven spectral lines, H-alpha 656.3 nm, Fe IX 435.9 nm, Fe X 637.4 nm, Fe XI 789.2 nm, Fe XIII 1074.7 nm, Fe XIV 530.3 nm and Ni XV 670.2 nm. The observations were made during the total solar eclipse of 11 July 2010 from the atoll of Tatakoto in French Polynesia. Simultaneous imaging with narrow bandpass filters in each of these spectral lines and in their corresponding underlying continua maximized the observing time during less than ideal observing conditions and yielded outstanding quality data. The application of two complementary image processing techniques revealed the finest details of coronal structures at 1" resolution in white light, and 6.5" in each of the spectral lines. This comprehensive wavelength coverage confirmed earlier eclipse findings that the solar corona has a clear two-temperature structure: The open field lines, expanding outwards from the solar surface, are characterized by electron temperatures near 1 X 10(exp 6) K, while the hottest plasma around 2X 10(exp 6) K resides in loop-like structures forming the bulges of streamers. The first images of the corona in the forbidden lines of Fe IX and Ni XV, showed that there was very little coronal plasma at temperatures below 5 X 10(exp 5) K and above 2.5X 10(exp 6) K. The data also enabled temperature differentiations as low as 0:2 X 10(exp 6) K in different density structures. These observations showed how the passage of CMEs through the corona, prior to totality, produced large scale ripples and very sharp streaks, which could be identified with distinct temperatures for the first time. The ripples were most prominent in emission from spectral lines associated with temperatures around 10(exp 6) K. The most prominent streak was associated with a conical-shaped void in the emission from the coolest line of Fe IX and from the hottest line of Ni XV. A prominence, which erupted prior to totality, appeared in the shape of a hook in the cooler lines of Fe X and Fe XI, spanning 0.5 R(solar) in extent starting at a heliocentric distance of 1.3 R(solar), with a complex trail of hot and cool twisted structures connecting it to the solar surface. Simultaneous Fe X 17.4 nm observations from space by Proba2/SWAP provided an ideal opportunity for comparing emission from a coronal forbidden line, namely Fe X 637.4 nm, with a space-based EUV allowed line. Comparison of the Fe X 17.4 nm and 637.4 nm emission provided the first textbook example of the role of radiative excitation in extending the detectability of coronal emission to much larger heliocentric distances than its collisionally excited component. These eclipse observations demonstrate the unique capabilities of coronal forbidden lines for exploring the evolution of the coronal magnetic field in the heliocentric distance range of 1 - 3 R(solar), which is currently inaccessible to any space-borne or ground-based observatory.

Development of a Microchannel High Temperature Recuperator for Fuel Cell Systems

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

Lukas, Michael

This report summarizes the progress made in development of microchannel recuperators for high temperature fuel cell/turbine hybrid systems for generation of clean power at very high efficiencies. Both Solid Oxide Fuel Cell/Turbine (SOFC/T) and Direct FuelCell/Turbine (DFC/T) systems employ an indirectly heated Turbine Generator to supplement fuel cell generated power. The concept extends the high efficiency of the fuel cell by utilizing the fuel cell’s byproduct heat in a Brayton cycle. Features of the SOFC/T and DFC/T systems include: electrical efficiencies of up to 65% on natural gas, minimal emissions, reduced carbon dioxide release to the environment, simplicity in design,more » and potential cost competitiveness with existing combined cycle power plants. Project work consisted of candidate material selection from FuelCell Energy (FCE) and Pacific Northwest National Laboratory (PNNL) institutional databases as well as from industrial and academic literature. Candidate materials were then downselected and actual samples were tested under representative environmental conditions resulting in further downselection. A microchannel thermal-mechanical model was developed to calculate overall device cost to be later used in developing a final Tier 1 material candidate list. Specifications and operating conditions were developed for both SOFC/T and DFC/T systems. This development included system conceptualization and progression to process flow diagrams (PFD’s) including all major equipment. Material and energy balances were then developed for the two types of systems which were then used for extensive sensitivity studies that used high temperature recuperator (HTR) design parameters (e.g., operating temperature) as inputs and calculated overall system parameters (e.g., system efficiency). The results of the sensitivity studies determined the final HTR design temperatures, pressure drops, and gas compositions. The results also established operating conditions and specifications for all equipment in the SOFC/T and DFC/T systems. Capital cost and Cost of Electricity (COE) sensitivity analyses have been completed for MW-scale SOFC/T and DFC/T systems. Environmental testing consisted of 1000-hour and 2000-hour dry air oxidation testing on leading candidate materials, used to rank order and, in part, develop a final Tier 1 material candidate list. A thermal-mechanical model was subsequently used to provide material and manufacturing cost estimations for microchannel HTR’s to further refine the Tier 1 candidates. A capital cost and 20-year levelized cost of electricity (COE) was developed for a MW-scale version of the SOFC/T system concept as well as for a MW-scale version of the DFC/T system concept. Test frameworks were established for subsequent long-term materials stability testing, including oxidation resistance and mechanical strength. Mechanical strength testing was then carried out by a third-party test laboratory. Technology demonstration vehicles (TDV’s) were designed and fabricated. Several iterations of TDV’s were fabricated, each improved over the previous build as far as fabrication techniques. Two of three fabricated TDV’s were integrated with the TDV Test Facility for hot-testing at simulated operating conditions. The second of these two was successfully hot-tested for over 1000 hours at simulated temperature and pressure. Post-test leakdown assessment showed negligible leakage at benchtop conditions of 30 psig, a considerable improvement over the previous TDV’s.« less

Spatiotemporal trends in extreme rainfall and temperature indices over Upper Tapi Basin, India

NASA Astrophysics Data System (ADS)

Sharma, Priyank J.; Loliyana, V. D.; S. R., Resmi; Timbadiya, P. V.; Patel, P. L.

2017-12-01

The flood risk across the globe is intensified due to global warming and subsequent increase in extreme temperature and precipitation. The long-term trends in extreme rainfall (1944-2013) and temperature (1969-2012) indices have been investigated at annual, seasonal, and monthly time scales using nonparametric Mann-Kendall (MK), modified Mann-Kendall (MMK), and Sen's slope estimator tests. The extreme rainfall and temperature indices, recommended by the Expert Team on Climate Change Detection Monitoring Indices (ETCCDMI), have been analyzed at finer spatial scales for trend detection. The results of trend analyses indicate decreasing trend in annual total rainfall, significant decreasing trend in rainy days, and increasing trend in rainfall intensity over the basin. The seasonal rainfall has been found to decrease for all the seasons except postmonsoon, which could affect the rain-fed agriculture in the basin. The 1- and 5-day annual maximum rainfalls exhibit mixed trends, wherein part of the basin experiences increasing trend, while other parts experience a decreasing trend. The increase in dry spells and concurrent decrease in wet spells are also observed over the basin. The extreme temperature indices revealed increasing trends in hottest and coldest days, while decreasing trends in coldest night are found over most parts of the basin. Further, the diurnal temperature range is also found to increase due to warming tendency in maximum temperature (T max) at a faster rate compared to the minimum temperature (T min). The increase in frequency and magnitude of extreme rainfall in the basin has been attributed to the increasing trend in maximum and minimum temperatures, reducing forest cover, rapid pace of urbanization, increase in human population, and thereby increase in the aerosol content in the atmosphere. The findings of the present study would significantly help in sustainable water resource planning, better decision-making for policy framework, and setting up infrastructure against flood disasters in Upper Tapi Basin, India.

Streetwise Urban Fiction

ERIC Educational Resources Information Center

Wright, David

2006-01-01

One of the hottest literary phenomena of recent years has been the explosion of what has been variously termed hip-hop, street, or urban fiction. Especially popular with younger African Americans, books in this genre are reaching an increasingly broad readership through ties to hip-hop music and culture. These crime stories generally revolve…

What's Hot: Texas and the Nation

ERIC Educational Resources Information Center

Cassidy, Jack; Ortlieb, Evan; Grote-Garcia, Stephanie

2016-01-01

For two decades the International Literacy Association (ILA) has published the "What's Hot, What's Not in Literacy Survey." In the last five years, the hottest topics featured on the lists have largely been connected to the English Language Arts Common Core State Standards (ELA CCSS)--a publication produced by the National Governors…

"Hottest Brand, Coolest Pedagogy": Approaches to Corporate Branding in Singapore's Higher Education Sector

ERIC Educational Resources Information Center

Ng, Carl Jon Way

2016-01-01

This article examines the corporate branding efforts of Singapore's publicly funded higher education institutions within a context of neoliberal marketization. Adopting a discourse-analytic perspective, it examines the kind of branding approaches employed by Singapore's universities and polytechnics, and how these approaches are realized…

Netbooks: Small but Powerful Friends

ERIC Educational Resources Information Center

Descy, Don E.

2009-01-01

Netbooks, sometimes called "mini-notebooks," are lightweight, small, and low-priced computers. Some writers ridicule them by calling them "one of the hottest tech toys of the year" (Saltzman, 2008). Others enthusiastically embrace them as "my perfect new travel companion" (Grossman, 2009). Netbooks are not toys. They are honest-to-goodness real…

The Challenges of Defining and Measuring Student Engagement in Science

ERIC Educational Resources Information Center

Sinatra, Gale M.; Heddy, Benjamin C.; Lombardi, Doug

2015-01-01

Engagement is one of the hottest research topics in the field of educational psychology. Research shows that multifarious benefits occur when students are engaged in their own learning, including increased motivation and achievement. However, there is little agreement on a concrete definition and effective measurement of engagement. This special…

Occupational Therapy--Real Help for Real Life

ERIC Educational Resources Information Center

Gibbs, Hope J.

2004-01-01

Occupational therapy is one of the hottest growing professions around. The American Occupational Therapy Association (AOTA) cites on its website (www.aota.org) that "the U.S. Department of Labor's Bureau of Labor Statistics reveals that the job outlook for occupational therapists will improve substantially in the next several years and will…

Visualising "Junk" DNA through Bioinformatics

ERIC Educational Resources Information Center

Elwess, Nancy L.; Latourelle, Sandra M.; Cauthorn, Olivia

2005-01-01

One of the hottest areas of science today is the field in which biology, information technology,and computer science are merged into a single discipline called bioinformatics. This field enables the discovery and analysis of biological data, including nucleotide and amino acid sequences that are easily accessed through the use of computers. As…

Chlorine doped graphene quantum dots: Preparation, properties, and photovoltaic detectors

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

Zhao, Jianhong; Xiang, Jinzhong, E-mail: jzhxiang@ynu.edu.cn; Tang, Libin, E-mail: scitang@163.com

Graphene quantum dots (GQDs) are becoming one of the hottest advanced functional materials because of the opening of the bandgap due to quantum confinement effect, which shows unique optical and electrical properties. The chlorine doped GQDs (Cl-GQDs) have been fabricated by chemical exfoliation of HCl treated carbon fibers (CFs), which were prepared from degreasing cotton through an annealing process at 1000 °C for 30 min. Raman study shows that both G and 2D peaks of GQDs may be redshifted (softened) by chlorine doping, leading to an n-type doping. The first vertical (Cl)-GQDs based photovoltaic detectors have been demonstrated, both the light absorbingmore » and electron-accepting roles for (Cl)-GQDs in photodetection have been found, resulting in an exceptionally big ratio of photocurrent to dark current as high as ∼10{sup 5} at room temperature using a 405 nm laser irradiation under the reverse bias voltage. The study expands the application of (Cl)-GQDs to the important optoelectronic detection devices.« less

A new species of Desmopachria Babington (Coleoptera: Dytiscidae) from Cuba with a prediction of its geographic distribution and notes on other Cuban species of the genus.

PubMed

Megna, Yoandri S; Sánchez-Fernández, David

2014-01-10

A new species, Desmopachria andreae sp. n. is described from Cuba. Diagnostic characters including illustrations of male genitalia are provided and illustrated for the five species of the genus occurring on the island. For these five species both a simple key to adults and maps of their known distribution in Cuba are also provided. Using a Maximun Entropy method (MaxEnt), a distribution model was developed for D. andreae sp.n. Based on the model's predictions, this species has a higher probability of occurring in high altitude forests (above 1000 m a.s.l.), characterised by relatively low temperatures especially during the hottest and wettest seasons, specifically, the mountainous areas of the Macizo de Guamuhaya (Central Cuba), Sierra Maestra (S Cuba) and Nipe-Sagua-Baracoa (NE Cuba). In some of these areas the species has not yet been recorded, and should be searched for in future field surveys.

Isotopic evidence for continental ice sheet in mid-latitude region in the supergreenhouse Early Cretaceous

PubMed Central

Yang, Wu-Bin; Niu, He-Cai; Sun, Wei-Dong; Shan, Qiang; Zheng, Yong-Fei; Li, Ning-Bo; Li, Cong-Ying; Arndt, Nicholas T.; Xu, Xing; Jiang, Yu-Hang; Yu, Xue-Yuan

2013-01-01

Cretaceous represents one of the hottest greenhouse periods in the Earth's history, but some recent studies suggest that small ice caps might be present in non-polar regions during certain periods in the Early Cretaceous. Here we report extremely negative δ18O values of −18.12‰ to −13.19‰ for early Aptian hydrothermal zircon from an A-type granite at Baerzhe in northeastern China. Given that A-type granite is anhydrous and that magmatic zircon of the Baerzhe granite has δ18O value close to mantle values, the extremely negative δ18O values for hydrothermal zircon are attributed to addition of meteoric water with extremely low δ18O, mostly likely transported by glaciers. Considering the paleoaltitude of the region, continental glaciation is suggested to occur in the early Aptian, indicating much larger temperature fluctuations than previously thought during the supergreenhouse Cretaceous. This may have impact on the evolution of major organism in the Jehol Group during this period. PMID:24061068

First Global Analysis of Saturation Artifacts in the VIIRS Infrared Channels and the Effects of Detector Aggregation

NASA Astrophysics Data System (ADS)

Wang, J.; Polivka, T. N.; Hyer, E. J.; Peterson, D. A.

2014-12-01

Unlike previous space-borne Earth-observing sensors, the Visible Infrared Imaging Radiometer Suite (VIIRS) employs aggregation to reduce downlink bandwidth requirements and preserve spatial resolution across the swath. To examine the potentially deleterious impacts of aggregation when encountering detector saturation, nearly four months of NOAA's Nightfire product were analyzed, which contains a subset of the hottest observed nighttime pixels. An empirical method for identifying saturation was devised. The 3.69 µm band (M12) was the most frequently-saturating band with 0.15% of the Nightfire pixels at or near the ~359 K hard saturation limit, with possible saturation also occurring in M14, M15, and M16. Artifacts consistent with detector saturation were seen with M12 temperatures as low as 330 K in the scene center. This partial saturation and aggregation influence must be considered when using VIIRS radiances for quantitative characterization of hot emission sources such as fires and gas flaring.

The influence of temperature on mortality and its Lag effect: a study in four Chinese cities with different latitudes.

PubMed

Bao, Junzhe; Wang, Zhenkun; Yu, Chuanhua; Li, Xudong

2016-05-04

Global climate change is one of the most serious environmental issues faced by humanity, and the resultant change in frequency and intensity of heat waves and cold spells could increase mortality. The influence of temperature on human health could be immediate or delayed. Latitude, relative humidity, and air pollution may influence the temperature-mortality relationship. We studied the influence of temperature on mortality and its lag effect in four Chinese cities with a range of latitudes over 2008-2011, adjusting for relative humidity and air pollution. We recorded the city-specific distributions of temperature and mortality by month and adopted a Poisson regression model combined with a distributed lag nonlinear model to investigate the lag effect of temperature on mortality. We found that the coldest months in the study area are December through March and the hottest months are June through September. The ratios of deaths during cold months to hot months were 1.43, 1.54, 1.37 and 1.12 for the cities of Wuhan, Changsha, Guilin and Haikou, respectively. The effects of extremely high temperatures generally persisted for 3 days, whereas the risk of extremely low temperatures could persist for 21 days. Compared with the optimum temperature of each city, at a lag of 21 days, the relative risks (95 % confidence interval) of extreme cold temperatures were 4.78 (3.63, 6.29), 2.38 (1.35, 4.19), 2.62 (1.15, 5.95) and 2.62 (1.44, 4.79) for Wuhan, Changsha, Guilin and Haikou, respectively. The respective risks were 1.35 (1.18, 1.55), 1.19 (0.96, 1.48), 1.22 (0.82, 1.82) and 2.47 (1.61, 3.78) for extreme hot temperatures, at a lag of 3 days. Temperature-mortality relationships vary among cities at different latitudes. Local governments should establish regional prevention and protection measures to more effectively confront and adapt to local climate change. The effects of hot temperatures predominantly occur over the short term, whereas those of cold temperatures can persist for an extended number of days.

Primary succession on slopes exposed to intense erosion: the case of Vesuvius Grand Cone

NASA Astrophysics Data System (ADS)

Stinca, Adriano; Battista Chirico, Giovanni; Bonanomi, Giuliano

2014-05-01

Mt. Vesuvius (1281 m a.s.l.) is an active volcano dominating the central part of the Campania Region coastline, with a distinctive barren crater summit, known as Grand Cone, formed during the eruption of AD 79. Local environmental factors hindered the colonization of the Vesuvius Grand Cone by vascular plants after the last eruptions of 1906 and 1944. The Grand Cone exhibits very steep planar slopes (33-35 degrees), covered by unconsolidated pyroclastic deposits, mainly formed by lapilli and gravels, characterized by an extremely low water holding capacity and very low organic matter and nitrogen contents, and exposed to intense water and wind erosion. In the last decade Genista aetnensis (Biv.) DC. (Fabaceae), has been expanding over the Grand Cone, facilitating the colonization by other species, especially herbaceous, with a dramatic change of the landscape appearance of the Vesuvius Grand Cone. G. aetnensis is a plant endemic of Mt. Etna and Eastern Sardinia and was firstly introduced at the base of Mt. Vesuvius within reforestation programs after the eruption of 1906. This plant is a nitrogen fixing species with a strong ability to colonize andosols, much more pronounced than the indigenous brooms (Cytisus scoparius and Spartium junceum). An intensive investigation has been conducted to explore the eco-hydrological processes driving the vegetation dynamics observed on the slopes of Grand Cone. Specific field surveys and laboratory experiments have been carried out to assess the effects of the G. aetnensis on soil physical and chemical properties, on the above- and below-ground microclimate, on the soil hydrological regime and on the distribution of coexisting species. The G. aetnensis triggers a pedogenetic process that contributes to a rapid increase of carbon and nitrogen stocks, available phosphorous, cation exchange capacity and a reduction of soil pH. The increase of carbon content also significantly improves the water retention properties in this coarse-textured soils, increasing the soil water content available for plants. Continuous monitoring of the microclimatic variables, both under and outside the canopy shading, reveals that the G. aetnensis canopy reduces the air and soil temperatures while keeping air humidity higher in the warmest hours of the day during the entire growing season, thus reducing soil water losses by evaporation. During the hottest day of the summer season, the canopy shading also mitigates the surface soil temperature maxima, which values outside the canopy shading are prohibitive for the survival of the vascular plants. Ultimately, the G. aetnensis creates an island of fertility under its canopy, by ameliorating the soil quality and by creating more favourable microclimate and soil hydrological conditions under its canopy, determining underneath the canopy a less stress prone environment that allows the colonization by less stress adapted species.

Taking the temperature of Earth's hottest crust

NASA Astrophysics Data System (ADS)

Korhonen, F. J.; Clark, C.; Brown, M.; Taylor, R. J. M.

2014-12-01

The limitations of conventional thermobarometry and petrogenetic grids for determining the peak P- T conditions of granulites are well known. These limitations have been overcome during the past decade with the calibration of single mineral thermometers, particularly Al-in-orthopyroxene, Zr-in-rutile and Ti-in-zircon, and the increased use of P- T pseudosection thermobarometry. Most recent studies of ultrahigh temperature (UHT) granulites (those formed at >900 °C) have used one or other of these methods to argue for peak metamorphic temperatures up to or beyond 1000 °C. Since models for the thermal evolution of orogens generally do not predict such extreme temperatures it is important to confirm their veracity. Here we combine in a single study single mineral thermometry with P- T pseudosection thermobarometry to provide a robust determination of peak temperature and tight constraints on the retrograde P- T path for one UHT granulite locality in the Eastern Ghats Province. This is the first study to apply the most recent update of the internally consistent thermodynamic dataset of Holland and Powell (2011) and the re-parameterized a- x models of White et al. (2014) and Wheller and Powell (2014) to UHT granulites. For two samples, we report Zr-in-rutile temperatures of >1000 °C and Ti-in-zircon temperatures of ∼900 °C, supported by Al-in-orthopyroxene temperatures of ∼900 °C, that correspond closely to those estimated using P- T pseudosections for conditions at the thermal peak and at the solidus on the retrograde P- T path, respectively. The P- T path is counter-clockwise in common with other UHT granulite localities in the Eastern Ghats Province. By demonstrating that UHT metamorphism at T > 1000 °C is real we provide a robust constraint that must be met by geodynamic models for the development of ultrahot orogens.

Periodic Analysis Between Solar Variability and the Earth's Temperature From Centuries to Ten Thousand Years

NASA Astrophysics Data System (ADS)

Zhao, X.; Feng, X. S.

2014-12-01

The global warming is one of the hottest topics for both scientists and the public at present. Strong evidences have shown that the global warming is related to the man-made increasing greenhouse gas levels. Besides the artificial factors, natural forces also contribute to the Earth's climate change. Among them, solar activity is an important ingredient of the natural driving forces of the Earth's climate. In this study, two data sets are adopted to investigate the periodicities of both solar activity and the variation of the Earth temperature as well as their correlations based on the wavelet analysis and cross correlation method. The first one is a directly measured data set covering centuries, while the second one is the reconstructed data during the past 11,000 years. The obtained results demonstrate that solar activity and the Earth's temperature have significant resonance cycles, and the Earth's temperature has periodic variations similar to those of solar activity. For centuries, these common periodicities include the 22-year cycle and the 50-year cycle. While for 11,000 years, they are the 200-year, 500-year, 1000-year, and 2000-year cycles. Correlation analysis reveals that the correlations between solar variability and the Earth's temperature are statistically significant. The correlation coefficient (C.C.) between the 11-year running averaged Total Solar Irradiance (TSI) and the ocean temperature is 0.88 during the past 133 years of global warming. While for 11,000 years, the C.C. between the 500-year running averages of sunspot number (SSN) and the Earth temperature (r=0.51, p=1%) is stronger than that between the temperature and the atmospheric CO2 concentration (r=0.35, p=10%). All these support that solar activity should have non-ignorable effects on the Earth's climate change, especially before the modern industrial time.

Local-scale analysis of temperature patterns over Poland during heatwave events

NASA Astrophysics Data System (ADS)

Krzyżewska, Agnieszka; Dyer, Jamie

2018-01-01

Heatwaves are predicted to increase in frequency, duration, and severity in the future, including over Central Europe where populations are sensitive to extreme temperature. This paper studies six recent major heatwave events over Poland from 2006 through 2015 using regional-scale simulations (10-km grid spacing, hourly frequency) from the Weather Research and Forecast (WRF) model to define local-scale 2-m temperature patterns. For this purpose, a heatwave is defined as at least three consecutive days with maximum 2-m air temperature exceeding 30 °C. The WRF simulations were validated using maximum daily 2-m temperature observations from 12 meteorological stations in select Polish cities, which were selected to have even spatial coverage across the study area. Synoptic analysis of the six study events shows that the inflow of tropical air masses from the south is the primary driver of heatwave onset and maintenance, the highest temperatures (and most vulnerable areas) occur over arable land and artificial surfaces in central and western Poland, while coastal areas in the north, mountain areas in the south, and forested and mosaic areas of smaller fields and pastures of the northwest, northeast, and southeast are less affected by prolonged periods of elevated temperatures. In general, regional differences in 2-m temperature between the hottest and coolest areas is about 2-4 °C. Large urban areas like Warsaw, or the large complex of artificial areas in the conurbation of Silesian cities, are also generally warmer than surrounding areas by roughly 2-4 °C, and even up to 6 °C, especially during the night. Additionally, hot air from the south of Poland flows through a low-lying area between two mountain ranges (Sudetes and Carpathian Mountains)—the so-called Moravian Gate—hitting densely populated urban areas (Silesian cities) and Cracow. These patterns occur only during high-pressure synoptic conditions with low cloudiness and wind and without any active fronts or mesoscale convective disturbances.

The Benefits of Using Dense Temperature Sensor Networks to Monitor Urban Warming

NASA Astrophysics Data System (ADS)

Twine, T. E.; Snyder, P. K.; Kucharik, C. J.; Schatz, J.

2015-12-01

Urban heat islands (UHIs) occur when urban and suburban areas experience temperatures that are elevated relative to their rural surroundings because of differences in the fraction of gray and green infrastructure. Studies have shown that communities most at risk for impacts from climate-related disasters (i.e., lower median incomes, higher poverty, lower education, and minorities) tend to live in the hottest areas of cities. Development of adequate climate adaptation tools for cities relies on knowledge of how temperature varies across space and time. Traditionally, a city's urban heat island has been quantified using near-surface air temperature measurements from a few sites. This methodology assumes (1) that the UHI can be characterized by the difference in air temperature from a small number of points, and (2) that these few points represent the urban and rural signatures of the region. This methodology ignores the rich information that could be gained from measurements across the urban to rural transect. This transect could traverse elevations, water bodies, vegetation fraction, and other land surface properties. Two temperature sensor networks were designed and implemented in the Minneapolis-Saint Paul, MN and Madison, WI metropolitan areas beginning in 2011 and 2012, respectively. Both networks use the same model sensor and record temperature every 15 minutes from ~150 sensors. Data from each network has produced new knowledge of how temperature varies diurnally and seasonally across the cities and how the UHI magnitude is influenced by weather phenomena (e.g., wind, snow cover, heat waves) and land surface characteristics such as proximity to inland lakes. However, the two metropolitan areas differ in size, population, structure, and orientation to water bodies. In addition, the sensor networks were established in very different manners. We describe these differences and present lessons learned from the design and ongoing efforts of these two dense networks located in the Midwest USA.

A numerical tool for the calculation of non-equilibrium ionisation states in the solar corona and other astrophysical plasma environments

NASA Astrophysics Data System (ADS)

Bradshaw, S. J.

2009-07-01

Context: The effects of non-equilibrium processes on the ionisation state of strongly emitting elements in the solar corona can be extremely difficult to assess and yet they are critically important. For example, there is much interest in dynamic heating events localised in the solar corona because they are believed to be responsible for its high temperature and yet recent work has shown that the hottest (≥107 K) emission predicted to be associated with these events can be observationally elusive due to the difficulty of creating the highly ionised states from which the expected emission arises. This leads to the possibility of observing instruments missing such heating events entirely. Aims: The equations describing the evolution of the ionisaton state are a very stiff system of coupled, partial differential equations whose solution can be numerically challenging and time-consuming. Without access to specialised codes and significant computational resources it is extremely difficult to avoid the assumption of an equilibrium ionisation state even when it clearly cannot be justified. The aim of the current work is to develop a computational tool to allow straightforward calculation of the time-dependent ionisation state for a wide variety of physical circumstances. Methods: A numerical model comprising the system of time-dependent ionisation equations for a particular element and tabulated values of plasma temperature as a function of time is developed. The tabulated values can be the solutions of an analytical model, the output from a numerical code or a set of observational measurements. An efficient numerical method to solve the ionisation equations is implemented. Results: A suite of tests is designed and run to demonstrate that the code provides reliable and accurate solutions for a number of scenarios including equilibration of the ion population and rapid heating followed by thermal conductive cooling. It is found that the solver can evolve the ionisation state to recover exactly the equilibrium state found by an independent, steady-state solver for all temperatures, resolve the extremely small ionisation/recombination timescales associated with rapid temperature changes at high densities, and provide stable and accurate solutions for both dominant and minor ion population fractions. Rapid heating and cooling of low to moderate density plasma is characterised by significant non-equilibrium ionisation conditions. The effective ionisation temperatures are significantly lower than the electron temperature and the values found are in close agreement with the previous work of others. At the very highest densities included in the present study an assumption of equilibrium ionisation is found to be robust. Conclusions: The computational tool presented here provides a straightforward and reliable way to calculate ionisation states for a wide variety of physical circumstances. The numerical code gives results that are accurate and consistent with previous studies, has relatively undemanding computational requirements and is freely available from the author.

TRANSITIONS IN THE CLOUD COMPOSITION OF HOT JUPITERS

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

Parmentier, Vivien; Fortney, Jonathan J.; Morley, Caroline

Over a large range of equilibrium temperatures, clouds shape the transmission spectrum of hot Jupiter atmospheres, yet their composition remains unknown. Recent observations show that the Kepler light curves of some hot Jupiters are asymmetric: for the hottest planets, the light curve peaks before secondary eclipse, whereas for planets cooler than ∼1900 K, it peaks after secondary eclipse. We use the thermal structure from 3D global circulation models to determine the expected cloud distribution and Kepler light curves of hot Jupiters. We demonstrate that the change from an optical light curve dominated by thermal emission to one dominated by scatteringmore » (reflection) naturally explains the observed trend from negative to positive offset. For the cool planets the presence of an asymmetry in the Kepler light curve is a telltale sign of the cloud composition, because each cloud species can produce an offset only over a narrow range of effective temperatures. By comparing our models and the observations, we show that the cloud composition of hot Jupiters likely varies with equilibrium temperature. We suggest that a transition occurs between silicate and manganese sulfide clouds at a temperature near 1600 K, analogous to the L / T transition on brown dwarfs. The cold trapping of cloud species below the photosphere naturally produces such a transition and predicts similar transitions for other condensates, including TiO. We predict that most hot Jupiters should have cloudy nightsides, that partial cloudiness should be common at the limb, and that the dayside hot spot should often be cloud-free.« less

Can temperate insects take the heat? A case study of the physiological and behavioural responses in a common ant, Iridomyrmex purpureus (Formicidae), with potential climate change.

PubMed

Andrew, Nigel R; Hart, Robert A; Jung, Myung-Pyo; Hemmings, Zac; Terblanche, John S

2013-09-01

Insects in temperate regions are predicted to be at low risk of climate change relative to tropical species. However, these assumptions have generally been poorly examined in all regions, and such forecasting fails to account for microclimatic variation and behavioural optimisation. Here, we test how a population of the dominant ant species, Iridomyrmex purpureus, from temperate Australia responds to thermal stress. We show that ants regularly forage for short periods (minutes) at soil temperatures well above their upper thermal limits (upper lethal temperature = 45.8 ± 1.3°C; CT(max) = 46.1°C) determined over slightly longer periods (hours) and do not show any signs of a classic thermal performance curve in voluntary locomotion across soil surface temperatures of 18.6-57°C (equating to a body temperature of 24.5-43.1°C). Although ants were present all year round, and dynamically altered several aspects of their thermal biology to cope with low temperatures and seasonal variation, temperature-dependence of running speed remained invariant and ants were unable to elevate high temperature tolerance using plastic responses. Measurements of microclimate temperature were higher than ant body temperatures during the hottest part of the day, but exhibited a stronger relationship with each other than air temperatures from the closest weather station. Generally close associations of ant activity and performance with microclimatic conditions, possibly to maximise foraging times, suggest I. purpureus displays highly opportunistic thermal responses and readily adjusts behaviour to cope with high trail temperatures. Increasing frequency or duration of high temperatures is therefore likely to result in an immediate reduction in foraging efficiency. In summary, these results suggest that (1) soil-dwelling temperate insect populations may be at higher risks of thermal stress with increased frequency or duration of high temperatures resulting from climate change than previously thought, however, behavioural cues may be able to compensate to some extent; and (2) indices of climate change-related thermal stress, warming tolerance and thermal safety margin, are strongly influenced by the scale of climate metrics employed. Copyright © 2013 Elsevier Ltd. All rights reserved.

Premature detonation of an NH₄NO₃ emulsion in reactive ground.

PubMed

Priyananda, Pramith; Djerdjev, Alex M; Gore, Jeff; Neto, Chiara; Beattie, James K; Hawkett, Brian S

2015-01-01

When NH4NO3 emulsions are used in blast holes containing pyrite, they can exothermally react with pyrite, causing the emulsion to intensively heat and detonate prematurely. Such premature detonations can inflict fatal and very costly damages. The mechanism of heating of the emulsions is not well understood though such an understanding is essential for designing safe blasting. In this study the heating of an emulsion in model blast holes was simulated by solving the heat equation. The physical factors contributing to the heating phenomenon were studied using microscopic and calorimetric methods. Microscopic studies revealed the continuous formation of a large number of gas bubbles as the reaction progressed at the emulsion-pyrite interface, which made the reacting emulsion porous. Calculations show that the increase in porosity causes the thermal conductivity of a reacting region of an emulsion column in a blast hole to decrease exponentially. This large reduction in the thermal conductivity retards heat dissipation from the reacting region causing its temperature to rise. The rise in temperature accelerates the exothermic reaction producing more heat. Simulations predict a migration of the hottest spot of the emulsion column, which could dangerously heat the primers and boosters located in the blast hole. Copyright © 2014 Elsevier B.V. All rights reserved.

Clouds on Hot Jupiters Illustration

NASA Image and Video Library

2016-10-18

Hot Jupiters are exoplanets that orbit their stars so tightly that their temperatures are extremely high, reaching over 2,400 degrees Fahrenheit (1600 Kelvin). They are also tidally locked, so one side of the planet always faces the sun and the other is in permanent darkness. Research suggests that the "dayside" is largely free of clouds, while the "nightside" is heavily clouded. This illustration represents how hot Jupiters of different temperatures and different cloud compositions might appear to a person flying over the dayside of these planets on a spaceship, based on computer modeling. Cooler planets are entirely cloudy, whereas hotter planets have morning clouds only. Clouds of different composition have different colors, whereas the clear sky is bluer than on Earth. For the hottest planets, the atmosphere is hot enough on the evening side to glow like a charcoal. Figure 1 shows an approximation of what various hot Jupiters might look like based on a combination of computer modeling and data from NASA's Kepler Space Telescope. From left to right it shows: sodium sulfide clouds (1000 to 1200 Kelvin), manganese sulfide clouds (1200 to 1600 Kelvin), magnesium silicate clouds (1600 to 1800 Kelvin), magnesium silicate and aluminum oxide clouds (1800 Kelvin) and clouds composed of magnesium silicate, aluminum oxide, iron and calcium titanate (1900 to 2200 Kelvin). http://photojournal.jpl.nasa.gov/catalog/PIA21074

Supportive Noninvasive Tool for the Diagnosis of Breast Cancer Using a Thermographic Camera as Sensor

PubMed Central

Garduño-Ramón, Marco Antonio; Vega-Mancilla, Sofia Giovanna; Morales-Henández, Luis Alberto; Osornio-Rios, Roque Alfredo

2017-01-01

Breast cancer is the leading disease in incidence and mortality among women in developing countries. The opportune diagnosis of this disease strengthens the survival index. Mammography application is limited by age and periodicity. Temperature is a physical magnitude that can be measured by using multiple sensing techniques. IR (infrared) thermography using commercial cameras is gaining relevance in industrial and medical applications because it is a non-invasive and non-intrusive technology. Asymmetrical temperature in certain human body zones is associated with cancer. In this paper, an IR thermographic sensor is applied for breast cancer detection. This work includes an automatic breast segmentation methodology, to spot the hottest regions in thermograms using the morphological watershed operator to help the experts locate the tumor. A protocol for thermogram acquisition considering the required time to achieve a thermal stabilization is also proposed. Breast thermograms are evaluated as thermal matrices, instead of gray scale or false color images, increasing the certainty of the provided diagnosis. The proposed tool was validated using the Database for Mastology Research and tested in a voluntary group of 454 women of different ages and cancer stages with good results, leading to the possibility of being used as a supportive tool to detect breast cancer and angiogenesis cases. PMID:28273793

Supportive Noninvasive Tool for the Diagnosis of Breast Cancer Using a Thermographic Camera as Sensor.

PubMed

Garduño-Ramón, Marco Antonio; Vega-Mancilla, Sofia Giovanna; Morales-Henández, Luis Alberto; Osornio-Rios, Roque Alfredo

2017-03-03

Breast cancer is the leading disease in incidence and mortality among women in developing countries. The opportune diagnosis of this disease strengthens the survival index. Mammography application is limited by age and periodicity. Temperature is a physical magnitude that can be measured by using multiple sensing techniques. IR (infrared) thermography using commercial cameras is gaining relevance in industrial and medical applications because it is a non-invasive and non-intrusive technology. Asymmetrical temperature in certain human body zones is associated with cancer. In this paper, an IR thermographic sensor is applied for breast cancer detection. This work includes an automatic breast segmentation methodology, to spot the hottest regions in thermograms using the morphological watershed operator to help the experts locate the tumor. A protocol for thermogram acquisition considering the required time to achieve a thermal stabilization is also proposed. Breast thermograms are evaluated as thermal matrices, instead of gray scale or false color images, increasing the certainty of the provided diagnosis. The proposed tool was validated using the Database for Mastology Research and tested in a voluntary group of 454 women of different ages and cancer stages with good results, leading to the possibility of being used as a supportive tool to detect breast cancer and angiogenesis cases.

Methanotrophic bacteria in warm geothermal spring sediments identified using stable-isotope probing.

PubMed

Sharp, Christine E; Martínez-Lorenzo, Azucena; Brady, Allyson L; Grasby, Stephen E; Dunfield, Peter F

2014-10-01

We investigated methanotrophic bacteria in sediments of several warm geothermal springs ranging in temperature from 22 to 45 °C. Methane oxidation was measured at potential rates up to 141 μmol CH4 d(-1) g(-1) sediment. Active methanotrophs were identified using (13) CH4 stable-isotope probing (SIP) incubations performed at close to in situ temperatures for each site. Quantitative (q) PCR of pmoA genes identified the position of the heavy ((13) C-labelled) DNA fractions in density gradients, and 16S rRNA gene pyrotag sequencing of the heavy fractions was performed to identify the active methanotrophs. Methanotroph communities identified in heavy fractions of all samples were predominated by species similar (≥ 95% 16S rRNA gene identities) to previously characterized Gammaproteobacteria and Alphaproteobacteria methanotrophs. Among the five hottest samples (45 °C), members of the Gammaproteobacteria genus Methylocaldum dominated in two cases, while three others were dominated by an OTU closely related (96.8% similarity) to the Alphaproteobacteria genus Methylocapsa. These results suggest that diverse methanotroph groups are adapted to warm environments, including the Methylocapsa-Methylocella-Methyloferula group, which has previously only been detected in cooler sites. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

It Hurts to Ignore Work Injury Roots

ERIC Educational Resources Information Center

Turner, Anne M.

2004-01-01

The author was talking with a friend not long ago about one of the hottest political topics in California these days--the high cost of the workers compensation system. "But libraries don't have to worry about that, do they?" asked her friend. "Aha!" I said. "Another stereotype! In fact, library work is very physical. And…

Teaching Art to Teens in Public Libraries

ERIC Educational Resources Information Center

Crawford Barniskis, Shannon

2013-01-01

One of the hottest terms among public librarians today is "content creation," which involves stuff that library patrons make instead of simply use in a library context. Videos, music, fiction, paintings, 3D printed materials, websites--all these are made in public libraries, and will increase in popularity as more libraries shift from purveyors of…

Fire-Walking

ERIC Educational Resources Information Center

Willey, David

2010-01-01

This article gives a brief history of fire-walking and then deals with the physics behind fire-walking. The author has performed approximately 50 fire-walks, took the data for the world's hottest fire-walk and was, at one time, a world record holder for the longest fire-walk (www.dwilley.com/HDATLTW/Record_Making_Firewalks.html). He currently…

Questions to Consider before Flipping

ERIC Educational Resources Information Center

Moran, Clarice M.; Young, Carl A.

2015-01-01

Flipping the classroom is one of the hottest new educational ideas that promises to increase student engagement. However, recent research suggests that not all content areas are equal when it comes to flipping. English language arts and humanities-based subjects may not benefit as much as math and science classes and, in fact, decrease student…

Evidence-Based Reading Practices for Response to Intervention

ERIC Educational Resources Information Center

Haager, Diane, Ed.; Klingner, Janette, Ed.; Vaughn, Sharon, Ed.

2007-01-01

In this volume, highly regarded authors in the field of reading research share what they know about today's hottest topic in education--Response to Intervention (RTI), the key to helping struggling students "before they fall behind." More than 30 expert contributors reveal what the latest research says about RTI's Three-Tier Approach:…

Learning from Experience: A Guide to Social Impact Bond Investing

ERIC Educational Resources Information Center

Berlin, Gordon L.

2016-01-01

The social sector's hottest "impact investing" product--the social impact bond (SIB)--has generated a range of reactions, from excitement to angst. An SIB uses private funds to pay for a social, educational, or health program, and the government repays investors (plus a return) only if the program achieves prespecified results. The…

The Future of Portable Devices is the "PITs"

ERIC Educational Resources Information Center

Peters, Tom; Bell, Lori

2006-01-01

According to recent media reports, MP3 players are one of the hottest gift item these days, particularly for adolescents. The broad success of these devices, however, has revealed flaws in the designers' noninclusive thinking. The accessibility challenges for these players are similar to those for other portable electronic gadgets, such as PDAs…

Integrating habitat status, human population pressure, and protection status into biodiversity conservation priority setting

USGS Publications Warehouse

Shi, Hua; Singh, Ashbindu; Kant, S.; Zhu, Zhiliang; Waller, E.

2005-01-01

Priority setting is an essential component of biodiversity conservation. Existing methods to identify priority areas for conservation have focused almost entirely on biological factors. We suggest a new relative ranking method for identifying priority conservation areas that integrates both biological and social aspects. It is based on the following criteria: the habitat's status, human population pressure, human efforts to protect habitat, and number of endemic plant and vertebrate species. We used this method to rank 25 hotspots, 17 megadiverse countries, and the hotspots within each megadiverse country. We used consistent, comprehensive, georeferenced, and multiband data sets and analytical remote sensing and geographic information system tools to quantify habitat status, human population pressure, and protection status. The ranking suggests that the Philippines, Atlantic Forest, Mediterranean Basin, Caribbean Islands, Caucasus, and Indo-Burma are the hottest hotspots and that China, the Philippines, and India are the hottest megadiverse countries. The great variation in terms of habitat, protected areas, and population pressure among the hotspots, the megadiverse countries, and the hotspots within the same country suggests the need for hotspot- and country-specific conservation policies.

Predicting thermo-mechanical behaviour of high minor actinide content composite oxide fuel in a dedicated transmutation facility

NASA Astrophysics Data System (ADS)

Lemehov, S. E.; Sobolev, V. P.; Verwerft, M.

2011-09-01

The European Facility for Industrial Transmutation (EFIT) of the minor actinides (MA), from LWR spent fuel is being developed in the integrated project EUROTRANS within the 6th Framework Program of EURATOM. Two composite uranium-free fuel systems, containing a large fraction of MA, are proposed as the main candidates: a CERCER with magnesia matrix hosting (Pu,MA)O 2-x particles, and a CERMET with metallic molybdenum matrix. The long-term thermal and mechanical behaviour of the fuel under the expected EFIT operating conditions is one of the critical issues in the core design. To make a reliable prediction of long-term thermo-mechanical behaviour of the hottest fuel rods in the lead-cooled version of EFIT with thermal power of 400 MW, different fuel performance codes have been used. This study describes the main results of modelling the thermo-mechanical behaviour of the hottest CERCER fuel rods with the fuel performance code MACROS which indicate that the CERCER fuel residence time can safely reach at least 4-5 effective full power years.

Capsaicinoids, amino acid and fatty acid profiles in different fruit components of the world hottest Naga king chilli (Capsicum chinense Jacq).

PubMed

Ananthan, R; Subhash, K; Longvah, T

2018-01-01

The world hottest Naga king chilli is cultivated and consumed in Northeast India. Capsaicinoids, amino acids and fatty acids were studied in fruit and fruit components of Naga king chilli. Capsaicinoid content was increased in each ripening stage and maximum level was observed at red color fruits. Total protein and fat content of placenta was 19.41 and 20.36% respectively. Capsaicinoids of placenta (7.35±2.241%) was higher followed by seed (3.83±1.358%) and pericarp (2.91±0.667%). Similarly, essential amino acid content was also higher in placenta compared to other components. Amino acid score ranged from 37 to 38 with cystine and methionine as limiting amino acid. Low level of palmitic, stearic and α-linolenic acid and very high level of linoleic acid were found in seeds. Total polyunsaturates of seeds were higher followed by whole fruit. Naga king chilli is unique due to its high capsaicinoid content and it offers potential crop for the future exploitation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of Ambient Temperature on Australian Northern Territory Public Hospital Admissions for Cardiovascular Disease among Indigenous and Non-Indigenous Populations

PubMed Central

Webb, Leanne; Bambrick, Hilary; Tait, Peter; Green, Donna; Alexander, Lisa

2014-01-01

Hospitalisations are associated with ambient temperature, but little is known about responses in population sub-groups. In this study, heat responses for Indigenous and non-Indigenous people in two age groups were examined for two categories of cardiac diseases using daily hospital admissions from five Northern Territory hospitals (1992–2011). Admission rates during the hottest five per cent of days and the coolest five per cent of days were compared with rates at other times. Among 25–64 year olds, the Indigenous female population was more adversely affected by very hot days than the non-Indigenous female population, with admission rates for ischaemic heart disease (IHD) increasing by 32%. People older than 65 were more sensitive to cold, with non-Indigenous male admissions for heart failure increasing by 64%, and for IHD by 29%. For older Indigenous males, IHD admissions increased by 52% during cold conditions. For older non-Indigenous females, increases in admissions for heart failure were around 50% on these cold days, and 64% for older Indigenous females. We conclude that under projected climate change conditions, admissions for IHD amongst younger Indigenous people would increase in hot conditions, while admissions among elderly people during cold weather may be reduced. The responses to temperature, while showing significant relationships across the Northern Territory, may vary by region. These variations were not explored in this assessment. PMID:24531121

Effects of climate change and land use on water resources in the Upper Colorado River Basin

USGS Publications Warehouse

Belnap, Jayne; Campbell, D.H.

2011-01-01

The health of the Colorado River watershed is critical to the socioeconomic and ecosystem well-being of the Southwestern United States. Water in springs, streams, and rivers supports a range of aquatic and riparian ecosystems that contain many endangered species. Terrestrial habitats support a wide array of plants and wildlife. In addition, this region is enjoyed by millions of people annually for its recreational and esthetic opportunities. The Colorado River provides water for about 25 million people and is used to irrigate 2.5 million acres of farmland. However, competition for this water is expected to increase as human populations dependent on this water are projected to increase to 38 million by 2020. Climate change is expected to further exacerbate water issues in this region. Drought in the Southwest during 2000-04, caused by both reduced precipitation and a series of the hottest years on record, resulted in streamflows lower than during the 1930s Dust Bowl or the 1950s. Increased temperatures alone are a major factor in reducing surface-water flows in this region. For instance, precipitation received during the winter of 2005 was at the 100-year average. However, low soil moisture and high January-July temperatures resulted in flows that were only 75 percent of average. Climate models predict future warmer temperatures and reduced precipitation in the Upper Colorado River Basin (UCRB), which would reduce water available to humans and ecosystems.

Application of probabilistic event attribution in the summer heat extremes in the western US to emissions traced to major industrial carbon producers

NASA Astrophysics Data System (ADS)

Mera, R. J.; Allen, M. R.; Mote, P.; Ekwurzel, B.; Frumhoff, P. C.; Rupp, D. E.

2015-12-01

Heat waves in the western US have become progressively more severe due to increasing relative humidity and nighttime temperatures, increasing the health risks of vulnerable portions of the population, including Latino farmworkers in California's Central Valley and other socioeconomically disadvantaged communities. Recent research has shown greenhouse gas emissions doubled the risk of the hottest summer days during the 2000's in the Central Valley, increasing public health risks and costs, and raising the question of which parties are responsible for paying these costs. It has been argued that these costs should not be taken up solely by the general public through taxation, but that additional parties can be considered, including multinational corporations who have extracted and marketed a large proportion of carbon-based fuels. Here, we apply probabilistic event attribution (PEA) to assess the contribution of emissions traced to the world's 90 largest major industrial carbon producers to the severity and frequency of these extreme heat events. Our research uses very large ensembles of regional climate model simulations to calculate fractional attribution of policy-relevant extreme heat variables. We compare a full forcings world with observed greenhouse gases, sea surface temperatures and sea ice extent to a counter-factual world devoid of carbon pollution from major industrial carbon producers. The results show a discernable fraction of record-setting summer temperatures in the western US during the 2000's can be attributed to emissions sourced from major carbon producers.

Corrosivities in a pilot-scale combustor of a British and two Illinois coals with varying chlorine contents

USGS Publications Warehouse

Chou, I.-Ming; Lytle, J.M.; Kung, S.C.; Ho, K.K.

2000-01-01

Many US boiler manufacturers have recommended limits on the chlorine (Cl) content (< 0.25% or < 0.3%) of coals to be used in their boilers. These limits were based primarily on extrapolation of British coal data to predict the probable corrosion behavior of US coals. Even though Cl-related boiler corrosion has not been reported by US utilities burning high-Cl Illinois coals, the manufacturer's limits affect the marketability of high-Cl Illinois coals. This study measured the relative rates of corrosion caused by two high-Cl coals (British and Illinois) and one low-Cl Illinois baseline coal under identical pilot-scale combustion conditions for about 1000 h which gave reliable comparisons. Temperatures used reflected conditions in boiler superheaters. The corrosion probes were fabricated from commercial alloy 304SS frequently used at the hottest superheater section of utility boilers. The results showed no evidence of direct correlation between the coal chlorine content and rate of corrosion. A correlation between the rate of corrosion and the metal temperature was obvious. The results suggested that the different field histories of corrosivity from burning high-Cl Illinois coal and high-Cl British coal occurred because of different metal temperatures operated in US and UK utility boilers. The results of this study can be combined into a database, which could be used for lifting the limits on chlorine contents of coals burned in utility boilers in the US.

Adaptive model-predictive controller for magnetic resonance guided focused ultrasound therapy.

PubMed

de Bever, Joshua; Todd, Nick; Payne, Allison; Christensen, Douglas A; Roemer, Robert B

2014-11-01

Minimising treatment time and protecting healthy tissues are conflicting goals that play major roles in making magnetic resonance image-guided focused ultrasound (MRgFUS) therapies clinically practical. We have developed and tested in vivo an adaptive model-predictive controller (AMPC) that reduces treatment time, ensures safety and efficacy, and provides flexibility in treatment set-up. The controller realises time savings by modelling the heated treatment cell's future temperatures and thermal dose accumulation in order to anticipate the optimal time to switch to the next cell. Selected tissues are safeguarded by a configurable temperature constraint. Simulations quantified the time savings realised by each controller feature as well as the trade-offs between competing safety and treatment time parameters. In vivo experiments in rabbit thighs established the controller's effectiveness and reliability. In all in vivo experiments the target thermal dose of at least 240 CEM43 was delivered everywhere in the treatment volume. The controller's temperature safety limit reliably activated and constrained all protected tissues to <9 CEM43. Simulations demonstrated the path independence of the controller, and that a path which successively proceeds to the hottest untreated neighbouring cell leads to significant time savings, e.g. when compared to a concentric spiral path. Use of the AMPC produced a compounding time-saving effect; reducing the treatment cells' heating times concurrently reduced heating of normal tissues, which eliminated cooling periods. Adaptive model-predictive control can automatically deliver safe, effective MRgFUS treatments while significantly reducing treatment times.

Influence of Flow Regulation on Summer Water Temperature: Sauce Grande River, Argentina

NASA Astrophysics Data System (ADS)

Casado, A.; Hannah, D. M.; Peiry, J.; Campo, A. M.

2012-12-01

This study quantifies the effects of the Paso de las Piedras Dam on the thermal behaviour of the Sauce Grande River, Argentina, during a summer season. A 30-day data set of continuous hourly data was assembled for eight stream temperature gauging sites deployed above and below the impoundment. Time series span the hottest period recorded during summer 2009 to evaluate variations in river water temperature under strong meteorological influence. The methods include: (i) analysis of the time series by inspecting the absolute differences in daily data (magnitude, timing, frequency, duration and rate of change), (ii) classification of diurnal regimes by using a novel regime 'shape' and 'magnitude' classifying method (RSMC), and (ii) quantification of the sensitivity of water temperature regimes to air temperature by computation of a novel sensitivity index (SI). Results showed that fluctuations in daily water temperatures were linked to meteorological drivers; however, spatial variability in the shape and the magnitude of the thermographs revealed the effects of the impoundment in regulating the thermal behaviour of the river downstream. An immediate cooling effect below the dam was evident. Mean daily temperatures were reduced in up to 4 °C, and described a warming trend in the downstream direction over a distance of at least 15 km (up to +2.3 °C). Diurnal cycles were reduced in amplitude and delayed in timing, and revealed a dominance of regime magnitude stability and regime shape climatic insensitivity over a distance of 8 km downstream. These findings provide new information about the water quality of the Sauce Grande River and inform management of flows to maintain the ecological integrity of the river system. Also, they motivate further analysis of potential correlates under varying hydrological and meteorological conditions. The methods presented herein have wider applicability for quantifying river thermal regimes and their sensitivity to climate and other drivers of change over a range of temporal and spatial scales.

Prediction of future subsurface temperatures in Korea

NASA Astrophysics Data System (ADS)

Lee, Y.; Kim, S. K.; Jeong, J.; SHIN, E.

2017-12-01

The importance of climate change has been increasingly recognized because it has had the huge amount of impact on social, economic, and environmental aspect. For the reason, paleoclimate change has been studied intensively using different geological tools including borehole temperatures and future surface air temperatures (SATs) have been predicted for the local areas and the globe. Future subsurface temperatures can have also enormous impact on various areas and be predicted by an analytical method or a numerical simulation using measured and predicted SATs, and thermal diffusivity data of rocks. SATs have been measured at 73 meteorological observatories since 1907 in Korea and predicted at same locations up to the year of 2100. Measured SATs at the Seoul meteorological observatory increased by about 3.0 K from the year of 1907 to the present. Predicted SATs have 4 different scenarios depending on mainly CO2 concentration and national action plan on climate change in the future. The hottest scenario shows that SATs in Korea will increase by about 5.0 K from the present to the year of 2100. In addition, thermal diffusivity values have been measured on 2,903 rock samples collected from entire Korea. Data pretreatment based on autocorrelation analysis was conducted to control high frequency noise in thermal diffusivity data. Finally, future subsurface temperatures in Korea were predicted up to the year of 2100 by a FEM simulation code (COMSOL Multiphysics) using measured and predicted SATs, and thermal diffusivity data in Korea. At Seoul, the results of predictions show that subsurface temperatures will increase by about 5.4 K, 3.0 K, 1.5 K, and 0.2 K from the present to 2050 and then by about 7.9 K, 4.8 K, 2.5 K, and 0.5 K to 2100 at the depths of 10 m, 50 m, 100 m, and 200 m, respectively. We are now proceeding numerical simulations for subsurface temperature predictions for 73 locations in Korea.

Effects of ambient temperature and early open-field response on the behaviour, feed intake and growth of fast- and slow-growing broiler strains.

PubMed

Nielsen, B L

2012-09-01

Increased activity improves broiler leg health, but also increases the heat production of the bird. This experiment investigated the effects of early open-field activity and ambient temperature on the growth and feed intake of two strains of broiler chickens. On the basis of the level of activity in an open-field test on day 3 after hatching, fast-growing Ross 208 and slow-growing i657 chickens were allocated on day 13 to one of the 48 groups. Each group included either six active or six passive birds from each strain and the groups were housed in floor-pens littered with wood chips and fitted with two heat lamps. Each group was fed ad libitum and subjected to one of the three temperature treatments: two (HH; 26°C), one (HC; 16°C to 26°C) or no (CC; 16°C) heat lamps turned on. Production and behavioural data were collected every 2 weeks until day 57. For both strains, early open-field activity had no significant effects on their subsequent behaviour or on any of the production parameters measured, and overall, the slow-growing strain was more active than the fast-growing strain. Ambient temperature had significant effects on production measures for i657 broilers, with CC chickens eating and weighing more, and with a less efficient feed conversion than HH chickens, with HC birds intermediate. A similar effect was found for Ross 208 only for feed intake from 27 to 41 days of age. Ross 208 chickens distributed themselves in the pen with a preference for cooler areas in the hottest ambient temperature treatments. In contrast, the behaviour of the slow-growing strain appeared to be relatively unaffected by the ambient temperature. In conclusion, fast-growing broilers use behavioural changes when trying to adapt to warm environments, whereas slow-growing broilers use metabolic changes to adapt to cooler ambient temperatures.

Degradation of TBC Systems in Environments Relevant to Advanced Gas Turbines for IGCC Systems

NASA Astrophysics Data System (ADS)

Bohna, Nathaniel Allan

Plasma sprayed (PS) thermal barrier coatings (TBCs) are used to provide thermal insulation for the hottest components in gas turbines. Zirconia stabilized with 7wt% yttria (7YSZ) is the most common ceramic top coat used for turbine blades. The 7YSZ coating can be degraded by the buildup of fly-ash deposits which can arise from the fuel source (coal/biomass) used in the combustion process in gas turbines. Fly-ash from the integrated gasification combined cycle (IGCC) process can result from coal-based syngas and also from ambient air which passes through the system. TBCs are also exposed to harsh gas environments containing CO2, SO2, and steam. As presented in this thesis, degradation from the combined effects of fly-ash and harsh gas atmosphere can severely limit TBC lifetimes. It is well established that degradation at very high temperatures (≥1250°C) from deposits consisting of the oxides CaO-MgO-Al2O3-SiO 2 results from extensive liquid silicate infiltration into the porous top coat of the YSZ. This infiltration causes early failure resulting from chemical and/or mechanical damage to the ceramic layer. Damage resulting from liquid infiltration, however, is not typically considered at relatively lower temperatures around 1100°C because liquid silicates would not be expected to form from the oxides in the deposit. A key focus of this study is to assess the mode and extent of TBC degradation at 1100°C in cases when some amount of liquid forms owing to the presence of K2SO4 as a minor ash constituent. Two types of liquid infiltrations are observed depending on the principal oxide (i.e., CaO or SiO2) in the deposit. The degradation is primarily the result of mechanical damage, which results from infiltration caused by the interaction of liquid K2SO4 with either the CaO or SiO2. The TBCs used in this work are representative of commonly used coatings used in the hottest sections of land-based gas turbines. The specimens consist of 7YSZ top coats deposited on superalloy (Rene' N5 and PWA 1484) substrates that had been coated with NiCoCrAlY bond coats. Two different top coats are studied: conventional low-density 7YSZ, and also dense vertically cracked coatings. The specific mechanisms of liquid infiltration resulting from CaO and SiO2 are studied by conducting isothermal exposures followed by detailed characterizations. The resulting consequences on cyclic lifetimes are also determined. Further, the cyclic lifetimes are studied in several gas atmospheres to examine the combined effect of deposit and gas atmosphere on TBC lifetime. This work identifies a TBC degradation mechanism which had previously not been considered. It will be clearly shown that deposit-induced attack of TBCs can be highly detrimental at an intermediate temperature like 1100°C.

OPACs and the Mobile Revolution

ERIC Educational Resources Information Center

Liston, Samuel

2009-01-01

Since the turn of the century, one of the hottest topics in the IT world has been the coming mobile revolution. While there's been some arguing over the details, the fundamental tenet of the mobile revolution is that lots and lots of people will start accessing web content from handheld portable devices instead of using a traditional laptop or…

A Capstone on Her Career

ERIC Educational Resources Information Center

Goldman, Jay P.

2005-01-01

Joan Raymond was just six months into a well-earned retirement following 20 demanding years in the superintendency of some of the hottest kitchens in the nation. But when some longtime friends told her about an opening in South Bend, Indiana, Raymond could not ignore the itch to give it one more whirl. Raymond found the school system in far more…

The Hipster Librarian's Guide to Teen Craft Projects

ERIC Educational Resources Information Center

Coleman, Tina; Llanes, Peggie

2008-01-01

It's not your grandmother's crafting projects! Instead, hip librarians as well as their teen patrons can engage in the hottest new DIY way of life, recycling everything from discarded books to Altoids tins. Getting hands-on and making the coolest crafts can be a way to encourage teens' individuality and growing sense of self. Whether projects are…

A Brand New Way of Looking at Library Marketing

ERIC Educational Resources Information Center

Germain, Carol Anne, Ed.

2008-01-01

Currently, one of the hottest topics in library marketing is branding. Over the years, businesses have utilized this technique to achieve commercial success. Is it possible for libraries to utilize this same strategy to promote their resources and services? One of the key components of a good branding campaign is passion, dedication, and a quality…

A La Carts: You Want Wireless Mobility? Have a COW

ERIC Educational Resources Information Center

Villano, Matt

2006-01-01

Computers on wheels, or COWs, combine the wireless technology of today with the audio/visual carts of yesteryear for an entirely new spin on mobility. Increasingly used by districts with laptop computing initiatives, COWs are among the hottest high-tech sellers in schools today, according to market research firm Quality Education Data. In this…

Raining a magma ocean: Thermodynamics of rocky planets after a giant impact

NASA Astrophysics Data System (ADS)

Stewart, S. T.; Lock, S. J.; Caracas, R.

2017-12-01

Rocky planets in exoplanetary systems have equilibrium temperatures up to a few 1000 K. The thermal evolution after a giant impact is sensitive to the equilibrium temperature. Post-impact rocky bodies are thermally stratified, with cooler, lower-entropy silicate overlain by vaporized, higher-entropy silicate. The radii of impact-vaporized rocky planets are much larger than the radii of equivalent condensed bodies. Furthermore, after some high-energy, high-angular momentum collisions, the post-impact body exceeds the corotation limit for a rocky planet and forms a synestia. Initially, volatiles and silicates are miscible at the high temperatures of the outer layer. If the equilibrium temperature with the star is lower than the silicate condensation temperature ( 2000 K), silicate droplets form at the photosphere and fall while volatile components remain in the vapor. Radiation and turbulent convection cool the vapor outer layer to the silicate vapor curve. A distinct magma ocean forms as the thermal profile crosses the silicate vapor curve and the critical curves for the volatiles. Near the temperatures and pressures of the critical curves, volatiles and silicates are partially soluble in each other. As the system continues cooling, the volatile vapor and silicate liquid separate toward the end member compositions, which are determined by the equilibrium temperature and the total vapor pressure of volatiles. If the equilibrium temperature with the star is near or above the condensation temperature for silicates, there would be limited condensation at the photosphere. Initially, the cooler lower mantle would slowly, diffusively equilibrate with the hotter upper mantle. In some cases, the thermal profile may cross the silicate vapor curve in the middle of the silicate layer, producing a silicate rain layer within the body. With continued evolution toward an adiabatic thermal profile, the body would separate into a silicate liquid layer underlying a silicate-volatile vapor layer. As the hottest rocky planets become tidally locked to their star, cooling progresses asymmetrically. The timing and degree of differentiation of rocky planets into silicate mantles and volatile atmospheres depends on the thermal evolution of vaporized rocky planets and may vary widely with equilibrium temperature.

Planck's view on the spectrum of the Sunyaev-Zeldovich effect

NASA Astrophysics Data System (ADS)

Erler, Jens; Basu, Kaustuv; Chluba, Jens; Bertoldi, Frank

2018-05-01

We present a detailed analysis of the stacked frequency spectrum of a large sample of galaxy clusters using Planck data, together with auxiliary data from the AKARI and IRAS missions. Our primary goal is to search for the imprint of relativistic corrections to the thermal Sunyaev-Zeldovich effect (tSZ) spectrum, which allow to measure the temperature of the intracluster medium. We remove Galactic and extragalactic foregrounds with a matched filtering technique, which is validated using simulations with realistic mock data sets. The extracted spectra show the tSZ signal at high significance and reveal an additional far-infrared (FIR) excess, which we attribute to thermal emission from the galaxy clusters themselves. This excess FIR emission from clusters is accounted for in our spectral model. We are able to measure the tSZ relativistic corrections at 2.2σ by constraining the mean temperature of our cluster sample to 4.4^{+2.1}_{-2.0} keV. We repeat the same analysis on a subsample containing only the 100 hottest clusters, for which we measure the mean temperature to be 6.0^{+3.8}_{-2.9} keV, corresponding to 2.0σ. The temperature of the emitting dust grains in our FIR model is constrained to ≃20 K, consistent with previous studies. Control for systematic biases is done by fitting mock clusters, from which we also show that using the non-relativistic spectrum for SZ signal extraction will lead to a bias in the integrated Compton parameter Y, which can be up to 14% for the most massive clusters. We conclude by providing an outlook for the upcoming CCAT-prime telescope, which will improve upon Planck with lower noise and better spatial resolution.

Solving the Excitation and Chemical Abundances in Shocks: The Case of HH 1

NASA Astrophysics Data System (ADS)

Giannini, T.; Antoniucci, S.; Nisini, B.; Bacciotti, F.; Podio, L.

2015-11-01

We present deep spectroscopic (3600-24700 Å ) X-shooter observations of the bright Herbig-Haro object HH 1, one of the best laboratories to study the chemical and physical modifications caused by protostellar shocks on the natal cloud. We observe atomic fine structure lines, H i and He i recombination lines and H2 ro-vibrational lines (more than 500 detections in total). Line emission was analyzed by means of Non-local Thermal Equilibiurm codes to derive the electron temperature and density, and for the first time we are able to accurately probe different physical regimes behind a dissociative shock. We find a temperature stratification in the range 4000 K \\div 80,000 K, and a significant correlation between temperature and ionization energy. Two density regimes are identified for the ionized gas, a more tenuous, spatially broad component (density ˜103 cm-3), and a more compact component (density ≥slant 105 cm-3) likely associated with the hottest gas. A further neutral component is also evidenced, having a temperature ≲10,000 K and a density >104 cm-3. The gas fractional ionization was estimated by solving the ionization equilibrium equations of atoms detected in different ionization stages. We find that neutral and fully ionized regions co-exist inside the shock. Also, indications in favor of at least partially dissociative shock as the main mechanism for molecular excitation are derived. Chemical abundances are estimated for the majority of the detected species. On average, abundances of non-refractory/refractory elements are lower than solar of about 0.15/0.5 dex. This indicates the presence of dust inside the medium, with a depletion factor of iron of ˜40%. Based on observations collected at the European Southern Observatory, (92.C-0058).

Vulnerability to heat-related mortality in Latin America: a case-crossover study in São Paulo, Brazil, Santiago, Chile and Mexico City, Mexico

PubMed Central

Bell, Michelle L; O’Neill, Marie S; Ranjit, Nalini; Borja-Aburto, Victor H; Cifuentes, Luis A; Gouveia, Nelson C

2008-01-01

Background Factors affecting vulnerability to heat-related mortality are not well understood. Identifying susceptible populations is of particular importance given anticipated rising temperatures from climatic change. Methods We investigated heat-related mortality for three Latin American cities (Mexico City, Mexico; São Paulo, Brazil; Santiago, Chile) using a case-crossover approach for 754 291 deaths from 1998 to 2002. We considered lagged exposures, confounding by air pollution, cause of death and susceptibilities by educational attainment, age and sex. Results Same and previous day apparent temperature were most strongly associated with mortality risk. Effect estimates remained positive though lowered after adjustment for ozone or PM10. Susceptibility increased with age in all cities. The increase in mortality risk for those ≥65 comparing the 95th and 75th percentiles of same-day apparent temperature was 2.69% (95% CI: −2.06 to 7.88%) for Santiago, 6.51% (95% CI: 3.57–9.52%) for São Paulo and 3.22% (95% CI: 0.93–5.57%) for Mexico City. Patterns of vulnerability by education and sex differed across communities. Effect estimates were higher for women than men in Mexico City, and higher for men elsewhere, although results by sex were not appreciably different for any city. In São Paulo, those with less education were more susceptible, whereas no distinct patterns by education were observed in the other cities. Conclusions Elevated temperatures are associated with mortality risk in these Latin American cities, with the strongest associations in São Paulo, the hottest city. The elderly are an important population for targeted prevention measures, but vulnerability by sex and education differed by city. PMID:18511489

Using electron-tunneling refrigerators to cool electrons, membranes, and sensors

NASA Astrophysics Data System (ADS)

Miller, Nathan A.

Many cryogenic devices require temperatures near 100 mK for optimal performance, such as thin-film, superconducting detectors. Examples include the submillimeter SCUBA camera on the James Clerk Maxwell Telescope, high-resolution X-ray sensors for semiconductor defect analysis, and a planned satellite to search for polarization in the cosmic microwave background. The cost, size, and complexity of refrigerators used to reach 100 mK (dilution and adiabatic demagnetization refrigerators) are significant and alternative technologies are desirable. We demonstrate work on developing a new option for cooling detectors to 100 mK bath temperatures. Solid-state refrigerators based on Normal metal/Insulator/Superconductor (NIS) tunnel junctions can provide cooling from pumped 3He bath temperatures (˜300 mK) to 100 mK. The cooling mechanism is the preferential tunneling of the highest energy (hottest) electrons from the normal metal through the biased tunnel junctions into the superconductor. When NIS refrigerators are combined with a micro-machined membrane, both the electrons and phonons of the membrane can be cooled. We have developed NIS-cooled membranes with both large temperature reductions and large cooling powers. We have shown the first cooling of a bulk material by cooling a neutron transmutation doped (NTD) thermistor. The fabrication of NIS refrigerators can be integrated with existing detector technology. For the first time, we have successfully integrated NIS refrigerators with both mm-wave and X-ray detectors. In particular, we have cooled X-ray detectors by more than 100 mK and have achieved a resolution of <10 eV at 6 keV at a bath temperature 85 mK above the transition temperature of the detector. The use of integrated NIS refrigerators makes the remarkable performance of cryogenic detectors available from 300 mK platforms. We have also performed preliminary work towards building a general-purpose cooling platform for microelectronics devices on separate chips.

Those Were Some of the Hottest Days of My Life: The Genesis of SCOLT

ERIC Educational Resources Information Center

Swanson, Pete

2015-01-01

The following article recounts the creation and development of the Southern Conference on Language Teaching (SCOLT) through the words of one of its founders, Dr. Herman Bostick. The article is not intended to tell the entire history of the founding of the organization, nor the full story of Dr. Bostick's contributions to the civil rights movement…

How Well Has NCLB Worked? How Do We Get the Revisions We Want?

ERIC Educational Resources Information Center

Lewis, Anne C.

2007-01-01

In this article, the author presents a description of Phi Delta Kappa International's 2006 Summit on Public Education. The 2006 Summit opened with a stimulating panel discussion on the hottest topic in education--the No Child Left Behind Act. The Summit's emphasis on NCLB had a clear purpose--to stimulate their members to become involved in the…

A Case Analysis of Business English Teacher Development in China with GDUFS as an Example

ERIC Educational Resources Information Center

Wenzhong, Zhu; Jingzi, Deng

2015-01-01

Business English education has evolved into a cross-disciplinary programme in China as one of the hottest majors pursued by students and professionals. As Business English teaching develops in terms of diversity, richness, and depth, the demands placed on the teacher are also increasing. The paper assumes that the kind of teachers with…

Donkey in Disguise: Jack Jennings and the Center on Education Policy

ERIC Educational Resources Information Center

Forster, Greg

2006-01-01

With the passage of the No Child Left Behind Act (NCLB), the proliferation of high school exit exams, the success of school choice initiatives, and a dozen other smaller if more bitter battles, education has become one of the hottest policy topics in Washington. That means there is a booming market for education experts, especially those who claim…

21st Century Skills: What Are They and How Do We Assess Them?

ERIC Educational Resources Information Center

Geisinger, Kurt F.

2016-01-01

One of the "hottest" topics in the educational measurement community in the past decade has been the assessment of 21st century skills. This special issue demonstrates work being performed in this realm. The present article provides a context for the four primary articles that follow and a brief but broad view of some models of 21st…

Top 10 Products of 2011

ERIC Educational Resources Information Center

American School & University, 2011

2011-01-01

In 2011, American School & University (AS&U) showcased some of the hottest products in the industry. This article presents the top ten most requested products as determined by readers. The top one on the list is the Bulb crusher which can cut recycling costs by 50%, can hold 1,350 4-foot lamps in a single 55-gallon drum, can crush a 4-foot lamp in…

Helping Academics Have Families and Tenure Too: Universities Discover Their Self-Interest

ERIC Educational Resources Information Center

Marcus, Jon

2007-01-01

"Did you have a kid and, if so, how?" is one of the hottest questions everywhere in higher education. Even as women overtake men among Americans receiving doctorates, a substantial body of new research shows that they are being discouraged from careers in academia because the timing and requirements of tenure make it so hard to raise families. In…

Bodice Rippers without the Bodice: Ten Male-on-Male Romances for a Core Collection

ERIC Educational Resources Information Center

Thomas, Devon

2011-01-01

One of the hottest growing segments of the romance genre is male-on-male (M/M) romance--gay romantic fiction mostly written and read by straight women. Featuring traditional romance conventions, including mistaken identities, star-crossed lovers, and happy endings, these stories show both physical and emotional intimacy between men. M/M builds on…

Mental health effects of climate change.

PubMed

Padhy, Susanta Kumar; Sarkar, Sidharth; Panigrahi, Mahima; Paul, Surender

2015-01-01

We all know that 2014 has been declared as the hottest year globally by the Meteorological department of United States of America. Climate change is a global challenge which is likely to affect the mankind in substantial ways. Not only climate change is expected to affect physical health, it is also likely to affect mental health. Increasing ambient temperatures is likely to increase rates of aggression and violent suicides, while prolonged droughts due to climate change can lead to more number of farmer suicides. Droughts otherwise can lead to impaired mental health and stress. Increased frequency of disasters with climate change can lead to posttraumatic stress disorder, adjustment disorder, and depression. Changes in climate and global warming may require population to migrate, which can lead to acculturation stress. It can also lead to increased rates of physical illnesses, which secondarily would be associated with psychological distress. The possible effects of mitigation measures on mental health are also discussed. The paper concludes with a discussion of what can and should be done to tackle the expected mental health issues consequent to climate change.

Detection of H-alpha emission in the hot white dwarf G191-B2B

NASA Astrophysics Data System (ADS)

Reid, Neill; Wegner, Gary

1988-12-01

High-resolution spectra of G191-B2B, the hottest known DA white dwarf were obtained which reveal emission in the core of the H-alpha line. The observations show little variation in the line profile over a period of four days, ruling out line-doubling in a close binary as an explanation. The observed emission cannot be due to a nearby red dwarf companion, while the absence of any spatially extended emission argues against either a planetary nebula remnant or local ionization of the interstellar medium. The determination of the systemic velocity, using the companion red dwarf G191-B2A, is 5 + or - 2 km/s and shows that both the H-alpha emission and the high-excitation species observed in the ultraviolet are redshifted by 19 + or - 3 km/s, suggesting a photospheric origin. The low redshift implies a mass of 0.45 solar mass for this hot white dwarf, although the uncertainties in the effective temperature and parallax permit masses in the range 0.29 to 0.60 solar mass.

Spectroscopic Analyses of the "Blue Hook" Stars in Omega Centauri: A Test of the Late Hot Flasher Scenario

NASA Technical Reports Server (NTRS)

Moehler, S.; Sweigart, Allan V.; Landsman, W. B.; Dreizler, S.; Rabin, Douglas M. (Technical Monitor)

2002-01-01

(Omega) Cen contains the largest population of very hot horizontal branch (HB) stars known in a globular cluster. Recent UV observations (Whitney et al. 1998; D'Cruz et al. 2000) show a significant population of hot stars below the zero-age horizontal branch ("blue hook" stars), which cannot be explained by canonical stellar evolution. Stars which suffer unusually large mass loss on the red giant branch and thus experience the helium core flash while descending the white dwarf cooling curve could populate this region. Theory predicts that these "late hot flashers" should show higher temperatures than the hottest canonical HB stars and should have helium- and carbon-rich atmospheres. We obtained and analysed medium resolution spectra of a sample of blue hook stars to derive their atmospheric parameters. The blue hook stars are indeed both hotter (T(sub eff)>35,000 K) and more helium-rich than classical extreme HB stars. In addition we find indications for a large enhancement of the carbon abundance relative to the cluster abundance.

Automatic segmentation of thermal images of diabetic-at-risk feet using the snakes algorithm

NASA Astrophysics Data System (ADS)

Etehadtavakol, Mahnaz; Ng, E. Y. K.; Kaabouch, Naima

2017-11-01

Diabetes is a disease with multi-systemic problems. It is a leading cause of death, medical costs, and loss of productivity. Foot ulcers are one generally known problem of uncontrolled diabetes that can lead to amputation signs of foot ulcers are not always obvious. Sometimes, symptoms won't even show up until ulcer is infected. Hence, identification of pre-ulceration of the plantar surface of the foot in diabetics is beneficial. Thermography has the potential to identify regions of the plantar with no evidence of ulcer but yet risk. Thermography is a technique that is safe, easy, non-invasive, with no contact, and repeatable. In this study, 59 thermographic images of the plantar foot of patients with diabetic neuropathy are implemented using the snakes algorithm to separate two feet from background automatically and separating the right foot from the left on each image. The snakes algorithm both separates the right and left foot into segmented different clusters according to their temperatures. The hottest regions will have the highest risk of ulceration for each foot. This algorithm also worked perfectly for all the current images.

Evolution simulation of lightning discharge based on a magnetohydrodynamics method

NASA Astrophysics Data System (ADS)

Fusheng, WANG; Xiangteng, MA; Han, CHEN; Yao, ZHANG

2018-07-01

In order to solve the load problem for aircraft lightning strikes, lightning channel evolution is simulated under the key physical parameters for aircraft lightning current component C. A numerical model of the discharge channel is established, based on magnetohydrodynamics (MHD) and performed by FLUENT software. With the aid of user-defined functions and a user-defined scalar, the Lorentz force, Joule heating and material parameters of an air thermal plasma are added. A three-dimensional lightning arc channel is simulated and the arc evolution in space is obtained. The results show that the temperature distribution of the lightning channel is symmetrical and that the hottest region occurs at the center of the lightning channel. The distributions of potential and current density are obtained, showing that the difference in electric potential or energy between two points tends to make the arc channel develop downwards. The arc channel comes into expansion on the anode surface due to stagnation of the thermal plasma and there exists impingement on the copper plate when the arc channel comes into contact with the anode plate.

Simulation of transformations of thin metal films heated by nanosecond laser pulses

NASA Astrophysics Data System (ADS)

Balandin, V. Yu.; Niedrig, R.; Bostanjoglo, O.

1995-01-01

The ablation of free-standing thin aluminum films by a nanosecond laser pulse was investigated by time-resolved transmission electron microscopy and numerical simulation. It was established that thin film geometry is particularly suited to furnish information on the mechanism of evaporation and the surface tension of the melt. In the case of aluminum the surface tension sigma as function of temperature can be approximated by two linear sections with a coefficient -0.3 x 10(exp -3) N/K m from the melting point 933 K up to 3000 K and -0.02 x 10(exp -3) N/K m above 3000 K, respectively, with sigma(993 K) = 0.9 N/m and sigma(8500 K) = 0. At lower pulse energies the films disintegrated predominantly by thermocapillary flow. Higher pulse energies produced volume evaporation, and a nonmonotonous flow, explained by recoil from evaporating atoms and thermocapillarity. The familiar equations of energy and motion, which presuppose separate and coherent vapor and liquid phases, were not adequate to describe the ablation of the hottest zone. Surface evaporation seemed to be marginal at all laser pulse energies used.

Phonon transport in single-layer boron nanoribbons

NASA Astrophysics Data System (ADS)

Zhang, Zhongwei; Xie, Yuee; Peng, Qing; Chen, Yuanping

2016-11-01

Inspired by the successful synthesis of three two-dimensional (2D) allotropes, the boron sheet has recently been one of the hottest 2D materials around. However, to date, phonon transport properties of these new materials are still unknown. By using the non-equilibrium Green’s function (NEGF) combined with the first principles method, we study ballistic phonon transport in three types of boron sheets; two of them correspond to the structures reported in the experiments, while the third one is a stable structure that has not been synthesized yet. At room temperature, the highest thermal conductance of the boron nanoribbons is comparable with that of graphene, while the lowest thermal conductance is less than half of graphene’s. Compared with graphene, the three boron sheets exhibit diverse anisotropic transport characteristics. With an analysis of phonon dispersion, bonding charge density, and simplified models of atomic chains, the mechanisms of the diverse phonon properties are discussed. Moreover, we find that many hybrid patterns based on the boron allotropes can be constructed naturally without doping, adsorption, and defects. This provides abundant nanostructures for thermal management and thermoelectric applications.

The Missing Link: Early Methane ("T") Dwarfs in the Sloan Digital Sky Survey.

PubMed

Leggett; Geballe; Fan; Schneider; Gunn; Lupton; Knapp; Strauss; McDaniel; Golimowski; Henry; Peng; Tsvetanov; Uomoto; Zheng; Hill; Ramsey; Anderson; Annis; Bahcall; Brinkmann; Chen; Csabai; Fukugita; Hennessy; Hindsley; Ivezic; Lamb; Munn; Pier; Schlegel; Smith; Stoughton; Thakar; York

2000-06-10

We report the discovery of three cool brown dwarfs that fall in the effective temperature gap between the latest L dwarfs currently known, with no methane absorption bands in the 1-2.5 µm range, and the previously known methane (T) dwarfs, whose spectra are dominated by methane and water. The newly discovered objects were detected as very red objects in the Sloan Digital Sky Survey imaging data and have JHK colors between the red L dwarfs and the blue Gl 229B-like T dwarfs. They show both CO and CH(4) absorption in their near-infrared spectra in addition to H(2)O, with weaker CH(4) absorption features in the H and K bands than those in all other methane dwarfs reported to date. Due to the presence of CH(4) in these bands, we propose that these objects are early T dwarfs. The three form part of the brown dwarf spectral sequence and fill in the large gap in the overall spectral sequence from the hottest main-sequence stars to the coolest methane dwarfs currently known.

Diffusion Barriers to Increase the Oxidative Life of Overlay Coatings

NASA Technical Reports Server (NTRS)

Nesbitt, James A.; Lei, Jih-Fen

1999-01-01

Currently, most blades and vanes in the hottest section of aero gas turbine engines require some type of coating for oxidation protection. Newly developed single crystal superalloys have the mechanical potential to operate at increasingly higher component temperatures. However, at these elevated temperatures, coating/substrate interdiffusion can shorten the protective life of the coating. Diffusion barriers between overlay coatings and substrates are being examined to extend the protective life of the coating. A previously- developed finite-difference diffusion model has been modified to predict the oxidative life enhancement due to use of a diffusion barrier. The original diffusion model, designated COSIM, simulates Al diffusion in the coating to the growing oxide scale as well as Al diffusion into the substrate. The COSIM model incorporates an oxide growth and spalling model to provide the rate of Al consumption during cyclic oxidation. Coating failure is predicted when the Al concentration at the coating surface drops to a defined critical level. The modified COSIM model predicts the oxidative life of an overlay coating when a diffusion barrier is present eliminating diffusion of Al from the coating into the substrate. Both the original and the modified diffusion models have been used to predict the effectiveness of a diffusion barrier in extending the protective life of a NiCrAl overlay coating undergoing cyclic oxidation at 1100 C.

Spatial Fluctuations of the Intergalactic Temperature-Density Relation After Hydrogen Reionization

NASA Astrophysics Data System (ADS)

Keating, Laura C.; Puchwein, Ewald; Haehnelt, Martin G.

2018-04-01

The thermal state of the post-reionization IGM is sensitive to the timing of reionization and the nature of the ionizing sources. We have modelled here the thermal state of the IGM in cosmological radiative transfer simulations of a realistic, extended, spatially inhomogeneous hydrogen reionization process, carefully calibrated with Lyα forest data. We compare these with cosmological simulations run using a spatially homogeneous ionizing background. The simulations with a realistic growth of ionized regions and a realistic spread in reionization redshifts show, as expected, significant spatial fluctuations in the temperature-density relation (TDR) of the post-reionization IGM. The most recently ionized regions are hottest and exhibit a flatter TDR. In simulations consistent with the average TDR inferred from Lyα forest data, these spatial fluctuations have a moderate but noticeable effect on the statistical properties of the Lyα opacity of the IGM at z ˜ 4 - 6. This should be taken into account in accurate measurements of the thermal properties of the IGM and the free-streaming of dark matter from Lyα forest data in this redshift range. The spatial variations of the TDR predicted by our simulations are, however, smaller by about a factor two than would be necessary to explain the observed large spatial opacity fluctuations on large (≥ 50 h-1 comoving Mpc) scales at z ≳ 5.5.

The urban heat island in a small city in coastal Portugal.

PubMed

Pinho, O S; Orgaz, M D

2000-11-01

This project arose from the need to study the phenomenon of the urban heat island, since only by recognising this phenomenon can we moderate it to improve the human and urban environments. Not only big cities develop urban heat islands. This study detected the presence and recorded the characteristics of an urban heat island in the small coastal city of Aveiro, Portugal. The study was developed through the scheduled measurements of air temperature and the analysis of the geographical, meteorological and urban conditions. The form and intensity of Aveiro's heat island are a response to the interaction of three principal factors: the urban morphology (the hottest zones in the city are those with the tallest and the highest density of buildings, without green spaces and with intense generation of heat from traffic, commerce and services); the meteorological conditions (the intensity of the island is at its maximum when the sky is totally clear and there is no wind, and at its minimum in those situations when there is atmospheric instability, such as wind, cloud and precipitation); and the proximity of the coastal lagoon (which borders the city to the west and northwest and moderates seasonal temperatures. The urban heat island influences the comfort and health of its inhabitants, thus urban planning is very important in the moderation and prevention of this phenomenon.

Spatial fluctuations of the intergalactic temperature-density relation after hydrogen reionization

NASA Astrophysics Data System (ADS)

Keating, Laura C.; Puchwein, Ewald; Haehnelt, Martin G.

2018-07-01

The thermal state of the post-reionization IGM is sensitive to the timing of reionization and the nature of the ionizing sources. We have modelled here the thermal state of the IGM in cosmological radiative transfer simulations of a realistic, extended, spatially inhomogeneous hydrogen reionization process, carefully calibrated with Ly α forest data. We compare these with cosmological simulations run using a spatially homogeneous ionizing background. The simulations with a realistic growth of ionized regions and a realistic spread in reionization redshifts show, as expected, significant spatial fluctuations in the temperature-density relation (TDR) of the post-reionization IGM. The most recently ionized regions are hottest and exhibit a flatter TDR. In simulations consistent with the average TDR inferred from Ly α forest data, these spatial fluctuations have a moderate but noticeable effect on the statistical properties of the Ly α opacity of the IGM at z ˜ 4-6. This should be taken into account in accurate measurements of the thermal properties of the IGM and the free-streaming of dark matter from Ly α forest data in this redshift range. The spatial variations of the TDR predicted by our simulations are, however, smaller by about a factor of 2 than would be necessary to explain the observed large spatial opacity fluctuations on large (≥50 h-1 comoving Mpc) scales atz ≳ 5.5.

Modeling the Effects of Inhomogeneous Aerosols on the Hot Jupiter Kepler-7b’s Atmospheric Circulation

NASA Astrophysics Data System (ADS)

Roman, Michael; Rauscher, Emily

2017-11-01

Motivated by observational evidence of inhomogeneous clouds in exoplanetary atmospheres, we investigate how proposed simple cloud distributions can affect atmospheric circulations and infrared emission. We simulated temperatures and winds for the hot Jupiter Kepler-7b using a three-dimensional atmospheric circulation model that included a simplified aerosol radiative transfer model. We prescribed fixed cloud distributions and scattering properties based on results previously inferred from Kepler-7b optical phase curves, including inhomogeneous aerosols centered along the western terminator and hypothetical cases in which aerosols additionally extended across much of the planet’s nightside. In all cases, a strong jet capable of advecting aerosols from a cooler nightside to dayside was found to persist, but only at the equator. Colder temperatures at mid and polar latitudes might permit aerosol to form on the dayside without the need for advection. By altering the deposition and redistribution of heat, aerosols along the western terminator produced an asymmetric heating that effectively shifts the hottest spot further east of the substellar point than expected for a uniform distribution. The addition of opaque high clouds on the nightside can partly mitigate this enhanced shift by retaining heat that contributes to warming west of the hotspot. These expected differences in infrared phase curves could place constraints on proposed cloud distributions and their infrared opacities for brighter hot Jupiters.

Piezoelectric Ceramics of the (1 − x)Bi0.50Na0.50TiO3–xBa0.90Ca0.10TiO3 Lead-Free Solid Solution: Chemical Shift of the Morphotropic Phase Boundary, a Case Study for x = 0.06

PubMed Central

Vivar-Ocampo, Rodrigo; Pardo, Lorena; Ávila, David; Morán, Emilio; González, Amador M.; Bucio, Lauro; Villafuerte-Castrejón, María-Elena

2017-01-01

Research and development of lead-free piezoelectric materials are still the hottest topics in the field of piezoelectricity. One of the most promising lead-free family of compounds to replace lead zirconate–titanate for actuators is that of Bi0.50Na0.50TiO3 (BNT) based solid solutions. The pseudo-binary (1 − x)Bi0.50Na0.50TiO3–xBa1 − yCayTiO3 system has been proposed for high temperature capacitors and not yet fully explored as piezoelectric material. In this work, the solid solution with x = 0.06 and y = 0.10 was obtained by two different synthesis routes: solid state and Pechini, aiming at using reduced temperatures, both in synthesis (<800 °C) and sintering (<1150 °C), while maintaining appropriated piezoelectric performance. Crystal structure, ceramic grain size, and morphology depend on the synthesis route and were analyzed by X-ray diffraction, together with scanning and transmission electron microscopy. The effects of processing and ceramic microstructure on the structural, dielectric, ferroelectric, and piezoelectric properties were discussed in terms of a shift of the Morphotropic Phase Boundary, chemically induced by the synthesis route. PMID:28773096

Piezoelectric Ceramics of the (1 - x)Bi0.50Na0.50TiO₃-xBa0.90Ca0.10TiO₃ Lead-Free Solid Solution: Chemical Shift of the Morphotropic Phase Boundary, a Case Study for x = 0.06.

PubMed

Vivar-Ocampo, Rodrigo; Pardo, Lorena; Ávila, David; Morán, Emilio; González, Amador M; Bucio, Lauro; Villafuerte-Castrejón, María-Elena

2017-07-01

Research and development of lead-free piezoelectric materials are still the hottest topics in the field of piezoelectricity. One of the most promising lead-free family of compounds to replace lead zirconate-titanate for actuators is that of Bi 0.50 Na 0.50 TiO₃ (BNT) based solid solutions. The pseudo-binary (1 - x )Bi 0.50 Na 0.50 TiO₃- x Ba 1 - y Ca y TiO₃ system has been proposed for high temperature capacitors and not yet fully explored as piezoelectric material. In this work, the solid solution with x = 0.06 and y = 0.10 was obtained by two different synthesis routes: solid state and Pechini, aiming at using reduced temperatures, both in synthesis (<800 °C) and sintering (<1150 °C), while maintaining appropriated piezoelectric performance. Crystal structure, ceramic grain size, and morphology depend on the synthesis route and were analyzed by X-ray diffraction, together with scanning and transmission electron microscopy. The effects of processing and ceramic microstructure on the structural, dielectric, ferroelectric, and piezoelectric properties were discussed in terms of a shift of the Morphotropic Phase Boundary, chemically induced by the synthesis route.

Sensitivities Affecting Heat and Urban Heat Island Effect on Local Scale Projected to Neighborhood Scale in Baltimore, Maryland

NASA Astrophysics Data System (ADS)

Sze, C.; Zaitchik, B. F.; Scott, A.

2015-12-01

Urban regions are often impacted more by heat than adjacent rural areas, which is a phenomenon known as the urban heat island (UHI) effect. Urban areas are also highly heterogeneous and notoriously difficult to monitor using standard meteorological protocols—the hottest microclimates within a city often occur in locations that lack open, representative installation sites that are an adequate distance from buildings and direct heat sources. To investigate the challenges of monitoring urban heat, this study examines the sensitivity of temperature and humidity sensors currently used in a Baltimore UHI monitoring network to differences in sun exposure, material on which the data collecting instrument is attached, and land cover class of the vicinity. Sensitivity to sun exposure and attachment site can be interpreted as sources of uncertainty for urban heat monitoring, while sensitivity to land cover may reflect a true source of local temperature and humidity variability. In this study, we present results from a test deployment designed to assess the sensitivity of heat measurements to each of these three factors. We then apply these results to interpret measurements taken across the entire Baltimore UHI monitoring network. These results can then be used to improve heat measurements and more accurately represent and quantify the UHI effect on a broader scale, such as in neighborhoods or urban centers.

Use of thermal infrared imaging for monitoring renewed dome growth at Mount St. Helens, 2004: Chapter 17 in A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006

USGS Publications Warehouse

Schneider, David J.; Vallance, James W.; Wessels, Rick L.; Logan, Matthew; Ramsey, Michael S.; Sherrod, David R.; Scott, William E.; Stauffer, Peter H.

2008-01-01

A helicopter-mounted thermal imaging radiometer documented the explosive vent-clearing and effusive phases of the eruption of Mount St. Helens in 2004. A gyrostabilized gimbal controlled by a crew member housed the radiometer and an optical video camera attached to the nose of the helicopter. Since October 1, 2004, the system has provided thermal and video observations of dome growth. Flights conducted as frequently as twice daily during the initial month of the eruption monitored rapid changes in the crater and 1980-86 lava dome. Thermal monitoring decreased to several times per week once dome extrusion began. The thermal imaging system provided unique observations, including timely recognition that the early explosive phase was phreatic, location of structures controlling thermal emissions and active faults, detection of increased heat flow prior to the extrusion of lava, and recognition of new lava extrusion. The first spines, 1 and 2, were hotter when they emerged (maximum temperature 700-730°C) than subsequent spines insulated by as much as several meters of fault gouge. Temperature of gouge-covered spines was about 200°C where they emerged from the vent, and it decreased rapidly with distance from the vent. The hottest parts of these spines were as high as 500-730°C in fractured and broken-up regions. Such temperature variation needs to be accounted for in the retrieval of eruption parameters using satellite-based techniques, as such features are smaller than pixels in satellite images.

The physiological demands of horseback mustering when wearing an equestrian helmet.

PubMed

Taylor, Nigel A S; Caldwell, Joanne N; Dyer, Rodd

2008-09-01

The hottest months on northern Australian cattle stations are from September to November, and it is during these months that horseback cattle mustering occurs. Stockmen wear clothing that restricts heat loss, and protective helmets have recently been introduced. Anecdotal evidence points to the possibility that helmets may increase the probability of developing heat illness, or reducing workplace performance. In this project, we quantified the working (thermal) environment on such cattle stations, and measured the metabolic demands on, and concurrent physiological strain in stockmen during mustering, whilst wearing an equestrian helmet. During horseback work, the average heart rate was 102.0 beats min(-1) (SD 14.0), with almost 90% of the time (238 min) spent working at intensities <50% of the heart rate reserve. The projected metabolic heat production during mustering ranged between 178 and 333 W (women), and between 212 and 542 W (men). The average core temperature was 37.6 degrees C, while the mean skin temperature averaged 34.1 degrees C. It was concluded that the working environment is, on average, thermally uncompensable during the mustering season. However, horseback mustering per se is a relatively low-intensity activity, interspersed with short periods of high-intensity work. This activity level was reflected within core temperatures, which rarely climbed above values associated with light-moderate exercise. Thus, whilst the climatic state was uncompensable, stockmen used behavioural strategies to minimise the risk of heat illness. Finally, it was observed that the helmet, though unpleasant to wear, did not appear to increase thermal strain in a manner that would disadvantage stockmen.

Velocity Characteristics of Evaporated Plasma using Hinode/EIS

NASA Technical Reports Server (NTRS)

Milligan, Ryan O.; Dennis, Brian R.

2009-01-01

This paper presents a detailed study of chromospheric evaporation using the EUV Imaging Spectrometer (EIS) onboard Hinode in conjunction with HXR observat,ions from RHESSI. The advanced capabilities of EIS were used to measure Doppler shifts in 15 emission lines covering the temperature range T=0.05-16 MK during the impulsive phase of a C-class flare on 2007 December 14. Blueshifts indicative of the evaporated material were observed in six emission lines from Fe XIV-XXIV (2-16 MK). Upflow velocity was found to scale with temperature as v(sub up) (kilometers per second) approximately equal to 5-17 T (MK). Although the hottest emission lines, Fe XXIII and Fe XXIV, exhibited upflows of greater than 200 kilometers per second, their line profiles were found to be dominated by a stationary component in stark contrast to the predictions of the standard flare model. Emission from O VI-Fe XIII lines (0.5-1.5 MK) was found to be redshifted by v(sub down) (kilometers per second) approximately equal to 60-17 T (MK) and was interpreted as the downward-moving 'plug' characteristic of explosive evaporation. These downflows occur at temperatures significantly higher than previously expected. Both upflows and downflows were spatially and temporally correlated with HXR emission observed by RHESSI that provided the properties of the electron beam deemed to be the driver of the evaporation. The energy contained in the electron beam was found to be greater than or equal to 10(sup 11) ergs per square centimeter per second consistent with the value required to drive explosive chromospheric evaporation from hydrodynamic simulations.

[The influence of weather conditions on the epidemiology of vector-borne diseases by the example of West Nile fever in Russia].

PubMed

Platonov, A E

2006-01-01

Climate changes must influence the incidence of vector-borne infections, but their effects cannot be revealed due to lack of long-term observations. The impact of short-term weather changes may be used as a model. In Russia the biggest numbers of clinical cases of mosquito-borne West Nile infection were registered in 1999 in Volgograd and Astrakhan regions. The analysis of climatic dataset since 1900 shows that 1999 was the hottest year in Volgograd in the 20th century due to a very mild winter (December-March) and a rather hot summer (June-September). The author of the article puts forward a hypothesis that high winter temperatures favored the survival of over-wintering mosquito vectors, and high summer temperature facilitated the growth of the virus in the mosquitoes, as well as propagation of the mosquitoes themselves. The author assumes that conventional threshold temperatures for "beneficial for WNF conditions" in Russia are > or = 3 degrees C in winter, and > or = 22 degrees C in summer. These conditions coincided only in 1948 and 1999. In Astrakhan the "beneficial for WNF conditions" were registered in 30 out of 147 years of observation, and in 12 years between 1964 and 2003. This is not surprising that Astrakhan region is endemic for WNF in accordance with clinical and epidemiological data collected since the sixties. These findings give some hints on the WNF predisposing factors, as well as possibility of weather surveillance and prediction of WNF outbreaks in temperate climatic zones such as Southern Russia.

Constraining the potential temperature of the Archaean mantle: A review of the evidence from komatiites

NASA Astrophysics Data System (ADS)

Nisbet, E. G.; Cheadle, M. J.; Arndt, N. T.; Bickle, M. J.

1993-09-01

The maximum potential temperature of the Archaean mantle is poorly known, and is best constrained by the MgO contents of komatiitic liquids, which are directly related to eruptive temperatures. However, most Archaean komatiites are significantly altered and it is difficult to assess the composition of the erupted liquid. Relatively fresh lavas from the SASKMAR suite, Belingwe Greenstone Belt, Zimbabwe (2.7 Ga) include chills of 25.6 wt.% MgO, and olivines ranging to Fo 93.6, implying eruption at around 1520°C. A chill sample from Alexo Township, Ontario (also 2.7 Ga) is 28 wt.% MgO, and associated olivines range to Fo 94.1, implying eruption at 1560°C. However, inferences of erupted liquids containing 32-33 wt.% MgO, from lavas in the Barberton Greenstone Belt, South Africa (3.45 Ga) and from the Perseverance Complex, Western Australia (2.7 Ga) may be challenged on the grounds that they contain excess (cumulate) olivine, or were enriched in Mg during alteration or metamorphism. Re-interpretation of olivine compositions from these rocks shows that they most likely contained a maximum of 29 wt.% MgO corresponding to an eruption temperature of 1580°C. This composition is the highest liquid MgO content of an erupted lava that can be supported with any confidence. The hottest modern magma, on Gorgona Island (0.155 Ga) contained 18-20% MgO and erupted at circa 1400°C. If 1580°C is taken as the temperature of the most magnesian known eruption, then the source mantle from which the liquids rose would have been at up to 2200°C at pressures of 18 GPa corresponding to a mantle potential temperature of 1900°C. These temperatures are in excess of the mantle temperatures predicted by secular cooling models, and thus komatiites can only be formed in hot rising convective jets in the mantle. This result requires that Archaean mantle jets may have been 300°C hotter than the Archaean ambient mantle temperature. This temperature difference is similar to the 200-300°C temperature difference between present day jets and ambient mantle temperatures. An important subsidiary result of this study is the confirmation that spinifex rocks may be cumulates and do not necessarily represent liquid compositions.

The Possibilities and Limitations of Gifted Education in Korea: A Look at the ISEP Science-Gifted Education Center

ERIC Educational Resources Information Center

Han, Ki-Soon

2007-01-01

Education for gifted children is currently one of the hottest educational issues in Korea. Much money and effort are being invested in this area of education. Recent announcements by the Korean Ministry of Education state that all children should be educated to the level of which they are capable, and the current program for gifted students should…

Forecasting Nutrition Research in 2020

DTIC Science & Technology

2014-01-01

one of the hottest topics in 2020. A better understanding of en- ergy balance and energy flux will likely...reduce their quality of life. Reductions in dosing and/or duration of medical treatment can render the therapy less effec- tive than intended, and it...maintain a course of health promotion. In the past, pedometers worn on the belt gave feedback regarding physical activity (e.g., the common goal

Dal "San Marco" al "Vega". (English Title: From "San Marco" to Vega)

NASA Astrophysics Data System (ADS)

Savi, E.

2017-10-01

Apart from the two superpowers, among the other countries Italy has had an important role in astronautics. The roots of Italian astronautics' history runs deep in the hottest years of the Cold War, and it had its first remarkable achievement in the San Marco project..after years of advanced technologies testing, they achieved European cooperation and built VEGA, the current Arianespace light launcher.

Forest fire weather in western Oregon and western Washington in 1958.

Treesearch

Owen P. Cramer

1958-01-01

In terms of general weather, the 1958 fire season will be classed as one of the hottest on record and as having unusually frequent spring and summer lightning storms. It was also unusual in that spring and most of the summer were less rainy in western Washington than in normally dry southwestern Oregon. Thus, until late August, cumulative fire-season rainfall ranged...

Rethinking phytophthora—research opportunities and management

Treesearch

Everett Hansen

2008-01-01

It was the second week of June, 2000, the hottest weather on record in San Francisco - hardly Phytophthora weather. But it was that week, at China Camp State Park, that Dave Rizzo and colleagues collected the bark samples from bleeding cankers on coast live oaks that finally moved sudden oak death (SOD) from the “cause unknown” category to “...

NIMS: hotspots on Io during G2

NASA Technical Reports Server (NTRS)

1996-01-01

The Near Infrared Mapping Spectrometer (NIMS) on the Galileo spacecraft imaged Io at high spectral resolution at a range of 439,000 km (275,000 miles) during the G2 encounter on 7 September 1996. This image shows (on the right) Io as seen in the infrared by NIMS. The image on the left shows the same view from Voyager in 1979. This NIMS image can be compared to the NIMS images from the G1 orbit (June 1996) to monitor changes on Io. The NIMS image is at 4.9 microns, showing thermal emissions from the hotspots. The brightness of the pixels is a function of size and temperature.

At least 10 hotspots have been identified and can be matched with surface features. An accurate determination of the position of the hotspot in the vicinity of Shamash Patera is pending. Hotspots are seen in the vicinity of Prometheus, Volund and Marduk, all sites of volcanic plume activity during the Galileo encounters, and also of active plumes in 1979. Temperatures and areas have been calculated for the hotspots shown. Temperatures range from 828 K (1031 F) to 210 K (- 81.4 F). The lowest temperature is significantly higher than the Io background (non-hotspot) surface temperature of about 100 K (-279 F). Hotspot areas range from 6.5 square km (2.5 sq miles) to 40,000 sq km (15,400 sq miles). The hottest hotspots have smallest areas, and the cooler hotspots have the largest areas. NIMS is continuing to observe Io to monitor volcanic activity throughout the Galileo mission.

The Galileo mission is managed by the Jet Propulsion Laboratory for NASA's Office of Space Science, Washington, D.C.

This image and other images and data received from Galileo are posted on the Galileo mission home page on the World Wide Web at http://galileo.jpl.nasa.gov.

Effect of the temperature-humidity index on body temperature and conception rate of lactating dairy cows in southwestern Japan.

PubMed

Nabenishi, Hisashi; Ohta, Hiroshi; Nishimoto, Toshihumi; Morita, Tetsuo; Ashizawa, Koji; Tsuzuki, Yasuhiro

2011-09-01

In the present study, we investigated the relationship between the temperature-humidity index (THI) and the conception rate of lactating dairy cows in southwestern Japan, one of the hottest areas of the country. We also investigated the relationship between measurement of the vaginal temperature of lactating dairy cows as their core body temperature at one-hour intervals for 25 consecutive days in hot (August-September, n=6) and cool (January-February, n=5) periods and their THI. Furthermore, we discussed the above relationship using these vaginal temperatures, the conception rates and the THI. As a result, when the conception rates from day 2 to 0 before AI were classified into day 2, 1 and 0 groups by the six maximum THI values in each group (mTHI; <61, 61-65, 66-70, 71-75, 76-80, >80), only the conception rate for the mTHI over 80 at 1 day before AI group was significantly lower (P<0.05) than the other groups. The conception rate for days 15 to 17, but not days 19 to 22 and 30 to 35, after AI in the cows that experienced average mTHI over 80 (amTHI>80) was significantly lower (P<0.05) than that of the cows that did not experience amTHI>80. There was a significant positive correlation (P<0.01) between the mTHI and the mean daily vaginal temperature, but not during the cool period. When the mTHI reached 69, the vaginal temperature started to increase. As for the relationship between the conception rates and vaginal temperatures for all mTHI classes, in the mTHI>80 at 1 day before AI group, the vaginal temperature increased by 0.6 C from 38.7 C, resulting in a reduction of 11.6% in the conception rate from 40.5%. In conclusion, these results suggest that one of the causes of the fall in conception rate of lactating dairy cows during the summer season in southwestern Japan may be an increase in their core body temperature with a higher mTHI than the critical mTHI of 69 at 1 day before AI.

History of Chandra X-Ray Observatory

NASA Image and Video Library

2004-08-23

This spectacular Chandra X-Ray Observatory (CXO) image of the supernova remnant Cassiopeia A is the most detailed image ever made of the remains of an exploded star. The one-million-second image shows a bright outer ring (green) 10 light years in diameter that marks the location of a shock wave generated by the supernova explosion. In the upper left corner is a large jet-like structure that protrudes beyond the shock wave, and a counter-jet can be seen on the lower right. The x-ray spectra show that the jets are rich in silicon atoms, and relatively poor in iron atoms. This indicates that the jets formed soon after the initial explosion of the star, otherwise, the jets should have contained large quantities of iron from the star’s central regions. The bright blue areas are composed almost purely of iron gas, which was produced in the central, hottest regions of the star and somehow ejected in a direction almost perpendicular to the jets. The bright source at the center of the image is presumed to be a neutron star created during the supernova. Unlike most others, this neutron star is quiet, faint, and so far shows no evidence of pulsed radiation. A working hypothesis is that the explosion that created Cassiopeia A produced high speed jets similar to, but less energetic than, the hyper nova jets thought to produce gamma-ray bursts. During the explosion, the star may have developed an extremely strong magnetic filed that helped to accelerate the jets and later stifled any pulsar wind activity. CXO project management is the responsibility of NASA’s Marshall Space Flight Center in Huntsville, Alabama.

Deepest Image of Exploded Star Uncovers Bipolar Jets

NASA Technical Reports Server (NTRS)

2004-01-01

This spectacular Chandra X-Ray Observatory (CXO) image of the supernova remnant Cassiopeia A is the most detailed image ever made of the remains of an exploded star. The one-million-second image shows a bright outer ring (green) 10 light years in diameter that marks the location of a shock wave generated by the supernova explosion. In the upper left corner is a large jet-like structure that protrudes beyond the shock wave, and a counter-jet can be seen on the lower right. The x-ray spectra show that the jets are rich in silicon atoms, and relatively poor in iron atoms. This indicates that the jets formed soon after the initial explosion of the star, otherwise, the jets should have contained large quantities of iron from the star's central regions. The bright blue areas are composed almost purely of iron gas, which was produced in the central, hottest regions of the star and somehow ejected in a direction almost perpendicular to the jets. The bright source at the center of the image is presumed to be a neutron star created during the supernova. Unlike most others, this neutron star is quiet, faint, and so far shows no evidence of pulsed radiation. A working hypothesis is that the explosion that created Cassiopeia A produced high speed jets similar to, but less energetic than, the hyper nova jets thought to produce gamma-ray bursts. During the explosion, the star may have developed an extremely strong magnetic filed that helped to accelerate the jets and later stifled any pulsar wind activity. CXO project management is the responsibility of NASA's Marshall Space Flight Center in Huntsville, Alabama.

Improved Battery State Estimation Using Novel Sensing Techniques

NASA Astrophysics Data System (ADS)

Abdul Samad, Nassim

Lithium-ion batteries have been considered a great complement or substitute for gasoline engines due to their high energy and power density capabilities among other advantages. However, these types of energy storage devices are still yet not widespread, mainly because of their relatively high cost and safety issues, especially at elevated temperatures. This thesis extends existing methods of estimating critical battery states using model-based techniques augmented by real-time measurements from novel temperature and force sensors. Typically, temperature sensors are located near the edge of the battery, and away from the hottest core cell regions, which leads to slower response times and increased errors in the prediction of core temperatures. New sensor technology allows for flexible sensor placement at the cell surface between cells in a pack. This raises questions about the optimal locations of these sensors for best observability and temperature estimation. Using a validated model, which is developed and verified using experiments in laboratory fixtures that replicate vehicle pack conditions, it is shown that optimal sensor placement can lead to better and faster temperature estimation. Another equally important state is the state of health or the capacity fading of the cell. This thesis introduces a novel method of using force measurements for capacity fade estimation. Monitoring capacity is important for defining the range of electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs). Current capacity estimation techniques require a full discharge to monitor capacity. The proposed method can complement or replace current methods because it only requires a shallow discharge, which is especially useful in EVs and PHEVs. Using the accurate state estimation accomplished earlier, a method for downsizing a battery pack is shown to effectively reduce the number of cells in a pack without compromising safety. The influence on the battery performance (e.g. temperature, utilization, capacity fade, and cost) while downsizing and shifting the nominal operating SOC is demonstrated via simulations. The contributions in this thesis aim to make EVs, HEVs and PHEVs less costly while maintaining safety and reliability as more people are transitioning towards more environmentally friendly means of transportation.

Improving the Performance of Temperature Index Snowmelt Model of SWAT by Using MODIS Land Surface Temperature Data

PubMed Central

Yang, Yan; Onishi, Takeo; Hiramatsu, Ken

2014-01-01

Simulation results of the widely used temperature index snowmelt model are greatly influenced by input air temperature data. Spatially sparse air temperature data remain the main factor inducing uncertainties and errors in that model, which limits its applications. Thus, to solve this problem, we created new air temperature data using linear regression relationships that can be formulated based on MODIS land surface temperature data. The Soil Water Assessment Tool model, which includes an improved temperature index snowmelt module, was chosen to test the newly created data. By evaluating simulation performance for daily snowmelt in three test basins of the Amur River, performance of the newly created data was assessed. The coefficient of determination (R 2) and Nash-Sutcliffe efficiency (NSE) were used for evaluation. The results indicate that MODIS land surface temperature data can be used as a new source for air temperature data creation. This will improve snow simulation using the temperature index model in an area with sparse air temperature observations. PMID:25165746

The Urban Heat Island Impact in Consideration of Spatial Pattern of Urban Landscape and Structure

NASA Astrophysics Data System (ADS)

Kim, J.; Lee, D. K.; Jeong, W.; Sung, S.; Park, J.

2015-12-01

Preceding study has established a clear relationship between land surface temperature and area of land covers. However, only few studies have specifically examined the effects of spatial patterns of land covers and urban structure. To examine how much the local climate is affected by the spatial pattern in highly urbanized city, we investigated the correlation between land surface temperature and spatial patterns of land covers. In the analysis of correlation, we categorized urban structure to four different land uses: Apartment residential area, low rise residential area, industrial area and central business district. Through this study, we aims to examine the types of residential structure and land cover pattern for reducing urban heat island and sustainable development. Based on land surface temperature, we investigated the phenomenon of urban heat island through using the data of remote sensing. This study focused on Daegu in Korea. This city, one of the hottest city in Korea has basin form. We used high-resolution land cover data and land surface temperature by using Landsat8 satellite image to examine 100 randomly selected sample sites of 884.15km2 (1)In each land use, we quantified several landscape-levels and class-level landscape metrics for the sample study sites. (2)In addition, we measured the land surface temperature in 3 year hot summer seasons (July to September). Then, we investigated the pattern of land surface temperature for each land use through Ecognition package. (3)We deducted the Pearson correlation coefficients between land surface temperature and each landscape metrics. (4)We analyzed the variance among the four land uses. (5)Using linear regression, we determined land surface temperature model for each land use. (6)Through this analysis, we aims to examine the best pattern of land cover and artificial structure for reducing urban heat island effect in highly urbanized city. The results of linear regression showed that proportional land cover of grass, tree, water and impervious surfaces well explained the temperature in apartment residential areas. In contrast, the changes in the pattern of water, grass, tree and impervious surfaces were the best to determine the temperature in low rise residential area, central business district and industrial area.

Distributed Ferrite Isolation in Traveling-Wave Tubes.

DTIC Science & Technology

coupling to broadband edge modes of ferrite slabs. Evidence of coupling to the lower branch of edge mode, i.e., magnetostatic, has been obtained with L...band helix . Cold tests and analysis suggest coupling to ferrite edge modes from helix is easier at higher microwave frequencies. Plans for a hot...test at the 1-2 kW power level is an L-band TWT incorporating such distributed ferrites are described.

Shifts in mortality during a hot weather event in Vancouver, British Columbia: rapid assessment with case-only analysis.

PubMed

Kosatsky, Tom; Henderson, Sarah B; Pollock, Sue L

2012-12-01

We assessed shifts in patterns of mortality during a hot weather event in greater Vancouver, British Columbia. We used a case-only analysis to compare characteristics of individuals who died during the hottest week of 2009 with those who died (1) during earlier summer weeks in 2009 and (2) during the same calendar weeks in the summers of 2001 through 2008. Compared with the 8 previous weeks of 2009, odds of mortality during the summer's hottest week were highest in the 65 to 74 years age category, compared with the 85 years and older category (odds ratio [OR] = 1.47; 95% confidence interval [CI] = 1.06, 2.03). The number of deaths at home increased over deaths in hospitals or institutions (OR = 1.43; 95% CI = 1.10, 1.86). Densely populated administrative health areas were more affected. A shift toward deaths at home suggests that in-home-based protective measures should be part of planning for hot weather events in greater Vancouver. Targeting should be considered for those aged 65 to 74 years. The case-only approach is quick and easy to apply and can provide useful information about localized, time-limited events.

Method and Apparatus of Implementing a Magnetic Shield Flux Sweeper

NASA Technical Reports Server (NTRS)

Sadleir, John E. (Inventor)

2018-01-01

The present invention relates to a method and apparatus of protecting magnetically sensitive devices with a shield, including: a non-superconducting metal or lower transition temperature (T.sub.c) material compared to a higher transition temperature material, disposed in a magnetic field; means for creating a spatially varying order parameter's |.PSI.(r,T)|.sup.2 in a non-superconducting metal or a lower transition temperature material; wherein a spatially varying order parameter is created by a proximity effect, such that the non-superconducting metal or the lower transition temperature material becomes superconductive as a temperature is lowered, creating a flux-free Meissner state at a center thereof, in order to sweep magnetic flux lines to the periphery.

Temperature distribution around thin electroconductive layers created on composite textile substrates

NASA Astrophysics Data System (ADS)

Korzeniewska, Ewa; Szczesny, Artur; Krawczyk, Andrzej; Murawski, Piotr; Mróz, Józef; Seme, Sebastian

2018-03-01

In this paper, the authors describe the distribution of temperatures around electroconductive pathways created by a physical vacuum deposition process on flexible textile substrates used in elastic electronics and textronics. Cordura material was chosen as the substrate. Silver with 99.99% purity was used as the deposited metal. This research was based on thermographic photographs of the produced samples. Analysis of the temperature field around the electroconductive layer was carried out using Image ThermaBase EU software. The analysis of the temperature distribution highlights the software's usefulness in determining the homogeneity of the created metal layer. Higher local temperatures and non-uniform distributions at the same time can negatively influence the work of the textronic system.

Thermal ecological physiology of native and invasive frog species: do invaders perform better?

PubMed

Cortes, Pablo A; Puschel, Hans; Acuña, Paz; Bartheld, José L; Bozinovic, Francisco

2016-01-01

Biological invasions are recognized as an important biotic component of global change that threatens the composition, structure and functioning of ecosystems, resulting in loss of biodiversity and displacement of native species. Although ecological characteristics facilitating the establishment and spread of non-native species are widely recognized, little is known about organismal attributes underlying invasion success. In this study, we tested the effect of thermal acclimation on thermal tolerance and locomotor performance in the invasive Xenopus laevis and the Chilean native Calyptocephalella gayi . In particular, the maximal righting performance (μ MAX ), optimal temperature ( T O ), lower (CT min ) and upper critical thermal limits (CT max ), thermal breadth ( T br ) and the area under the performance curve (AUC) were studied after 6 weeks acclimation to 10 and 20°C. We observed higher values of μ max and AUC in X. laevis in comparison to C. gayi . On the contrary, the invasive species showed lower values of CT min in comparison to the native one. In contrast, CT max , T O and T br showed no inter-specific differences. Moreover, we found that both species have the ability to acclimate their locomotor performance and lower thermal tolerance limit at low temperatures. Our results demonstrate that X. laevis is a better performer than C. gayi . Although there were differences in CT min , the invasive and native frogs did not differ in their thermal tolerance. Interestingly, in both species the lower and upper critical thermal limits are beyond the minimal and maximal temperatures encountered in nature during the coldest and hottest month, respectively. Overall, our findings suggest that both X. laevis and C. gayi would be resilient to climate warming expectations in Chile.

Prognosis and comparison of performances of composite CERCER and CERMET fuels dedicated to transmutation of TRU in an EFIT ADS

NASA Astrophysics Data System (ADS)

Sobolev, V.; Uyttenhove, W.; Thetford, R.; Maschek, W.

2011-07-01

The neutronic and thermomechanical performances of two composite fuel systems: CERCER with (Pu,Np,Am,Cm)O 2-x fuel particles in ceramic MgO matrix and CERMET with metallic Mo matrix, selected for transmutation of minor actinides in the European Facility for Industrial Transmutation (EFIT), were analysed aiming at their optimisation. The ALEPH burnup code system, based on MNCPX and ORIGEN codes and JEFF3.1 nuclear data library, and the modern version of the fuel rod performance code TRAFIC were used for this analysis. Because experimental data on the properties of the mixed minor-actinide oxides are scarce, and the in-reactor behaviour of the T91 steel chosen as cladding, as well as of the corrosion protective layer, is still not well-known, a set of "best estimates" provided the properties used in the code. The obtained results indicate that both fuel candidates, CERCER and CERMET, can satisfy the fuel design and safety criteria of EFIT. The residence time for both types of fuel elements can reach about 5 years with the reactivity swing within ±1000 pcm, and about 22% of the loaded MA is transmuted during this period. However, the fuel centreline temperature in the hottest CERCER fuel rod is close to the temperature above which MgO matrix becomes chemically instable. Moreover, a weak PCMI can appear in about 3 years of operation. The CERMET fuel can provide larger safety margins: the fuel temperature is more than 1000 K below the permitted level of 2380 K and the pellet-cladding gap remains open until the end of operation.

Weak metal lines in optical high-resolution Very Large Telescope and Keck spectra of "cool" PG 1159 stars

NASA Astrophysics Data System (ADS)

Werner, K.; Rauch, T.

2014-09-01

PG 1159 stars are very hot (effective temperatures Teff = 75 000-200 000 K), hydrogen-deficient (pre-) white dwarfs. They probably are the result of a late helium-shell flash that laid bare the He, C, and O rich intershell matter of the progenitor Asymptotic Giant Branch (AGB) star. Their chemical surface composition thus allows to conclude on details of AGB-star nucleosynthesis. Due to their very high effective temperatures, detailed spectral analyses are usually completely reliant on ultraviolet observations, except for some species in the hottest PG 1159 stars (Teff ≳ 130 000 K), which do exhibit highly excited lines from the CNO elements and neon (C iv, N v, O vi, Ne vii-viii) in optical spectra. Particularly problematic are, however, the coolest members of the PG 1159 class that exclusively show C iv lines in the optical. Access to the nitrogen abundance is important to decide which of the late-thermal pulse evolutionary scenarios was experienced by a particular star, while a high oxygen abundance is an important marker that the star could pulsate. In the present paper, we investigate high-resolution high signal-to-noise optical spectra of three "cool" PG 1159 stars (PG 0122+200, PG 2131+066, MCT 0130-1937, Teff = 80 000-95 000 K). With the help of non-LTE model atmospheres and synthetic spectra, we are able to identify a large number of weak CNO lines (C iii, N iv, O iii-v) that were not detected before in these stars. They allow abundance determinations and enable us to constrain the effective temperature to high precision through ionization equilibria without the requirement to access the ultraviolet spectral range.

Present limits to heat-adaptability in corals and population-level responses to climate extremes.

PubMed

Riegl, Bernhard M; Purkis, Sam J; Al-Cibahy, Ashraf S; Abdel-Moati, Mohammed A; Hoegh-Guldberg, Ove

2011-01-01

Climate change scenarios suggest an increase in tropical ocean temperature by 1-3°C by 2099, potentially killing many coral reefs. But Arabian/Persian Gulf corals already exist in this future thermal environment predicted for most tropical reefs and survived severe bleaching in 2010, one of the hottest years on record. Exposure to 33-35°C was on average twice as long as in non-bleaching years. Gulf corals bleached after exposure to temperatures above 34°C for a total of 8 weeks of which 3 weeks were above 35°C. This is more heat than any other corals can survive, providing an insight into the present limits of holobiont adaptation. We show that average temperatures as well as heat-waves in the Gulf have been increasing, that coral population levels will fluctuate strongly, and reef-building capability will be compromised. This, in combination with ocean acidification and significant local threats posed by rampant coastal development puts even these most heat-adapted corals at risk. WWF considers the Gulf ecoregion as "critically endangered". We argue here that Gulf corals should be considered for assisted migration to the tropical Indo-Pacific. This would have the double benefit of avoiding local extinction of the world's most heat-adapted holobionts while at the same time introducing their genetic information to populations naïve to such extremes, potentially assisting their survival. Thus, the heat-adaptation acquired by Gulf corals over 6 k, could benefit tropical Indo-Pacific corals who have <100 y until they will experience a similarly harsh climate. Population models suggest that the heat-adapted corals could become dominant on tropical reefs within ∼20 years.

Atmospheric characterization of the hot Jupiter Kepler-13Ab

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

Shporer, Avi; O'Rourke, Joseph G.; Knutson, Heather A.

Kepler-13Ab (= KOI-13.01) is a unique transiting hot Jupiter. It is one of very few known short-period planets orbiting a hot A-type star, making it one of the hottest planets currently known. The availability of Kepler data allows us to measure the planet's occultation (secondary eclipse) and phase curve in the optical, which we combine with occultations observed by warm Spitzer at 4.5 μm and 3.6 μm and a ground-based occultation observation in the K{sub s} band (2.1 μm). We derive a day-side hemisphere temperature of 2750 ± 160 K as the effective temperature of a black body showing themore » same occultation depths. Comparing the occultation depths with one-dimensional planetary atmosphere models suggests the presence of an atmospheric temperature inversion. Our analysis shows evidence for a relatively high geometric albedo, A {sub g} = 0.33{sub −0.06}{sup +0.04}. While measured with a simplistic method, a high A {sub g} is supported also by the fact that the one-dimensional atmosphere models underestimate the occultation depth in the optical. We use stellar spectra to determine the dilution, in the four wide bands where occultation was measured, due to the visual stellar binary companion 1.''15 ± 0.''05 away. The revised stellar parameters measured using these spectra are combined with other measurements, leading to revised planetary mass and radius estimates of M{sub p} = 4.94-8.09 M {sub J} and R{sub p} = 1.406 ± 0.038 R {sub J}. Finally, we measure a Kepler midoccultation time that is 34.0 ± 6.9 s earlier than expected based on the midtransit time and the delay due to light-travel time and discuss possible scenarios.« less

Discrepancies between anomalously low reflectance of vitrinite and other maturation indicators from an upper Miocene oil source rock, Los Angeles basin, California

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

Walker, A.L.; McCulloch, T.H.; Petersen, N.F.

1983-03-01

Forty-four subsurface samples of the nodular shale were collected from 14 selected wells located mostly between the Playa del Rey and Crescent Heights oil fields. Sites were selected to give the widest available range of sample depth and temperature where present burial depths are maximal, and where geothermal gradients are firmly established. Median random reflectance (%R/sub 0/) of first-cycle vitrinite is least in the shallowest samples, clusters about 0.24% in the deeper samples, and exceeds 0.30% only in the deepest and hottest samples. Extremes in the range of measured median %R/sub 0/ are tabulated below with corresponding extremes of samplemore » temperatures, depths, Time-Temperature Indices (TTI), and calculated %R/sub 0/ equivalents of the TTI values. All measured values of R/sub 0/ are significantly depressed compared to other maturity criteria. Significantly, second-cycle and oxidized vitrinite from these same samples show normally elevated reflectance. Eight of the samples processed for reflectance measurements were analyzed for total organic carbon content, which ranges from 2.21 to 9.41%. Most of the organic detritus is amorphous degraded algal material; less than 10% is structured vitrinite. Thermal alteration index values for the amorphous material range from 2 to 2 1/2, corresponding with hypothetical conversion R/sub 0/ values between 0.45 and 0.75%, again notably higher than the measured values. The ratios of extractable hydrocarbons to TOC in the 8 samples suggest mature levels of thermal evolution, as do carbon preference indices of 0.93 and 1.14 from extracts of 2 samples.« less

Passive heat exposure induced by hot water leg immersion increased oxyhemoglobin in pre-frontal cortex to preserve oxygenation and did not contribute to impaired cognitive functioning

NASA Astrophysics Data System (ADS)

Wijayanto, Titis; Toramoto, Sayo; Tochihara, Yutaka

2013-07-01

This study investigated the effects of passive heat exposure on pre-frontal cortex oxygenation and cognitive functioning, specifically to examine whether the change in pre-frontal cortex oxygenation coincided with cognitive functioning during heat exposure. Eleven male students who participated in this study immersed their lower legs to the knees in three different water temperatures, 38 °C, 40 °C, and 42 °C water in an air temperature of 28 º C and 50 % relative humidity for 60 min. After 45 min of leg immersion they performed cognitive functioning tasks assessing their short-term memory while immersing their lower legs. There were higher rectal temperature ( P < 0.05) and higher increase of oxyhemoglobin in both left ( P < 0.05) and right ( P < 0.05) pre-frontal cortex at the final stage of 45-min leg immersion in the 42 °C condition with unaltered tissue oxygenation index among the three conditions ( P > 0.05). No statistical difference in cognitive functioning among the three conditions was observed with a higher increase of oxyhemoglobin during the cognitive functioning in the 42 °C condition for the left ( P = 0.05) and right ( P < 0.05) pre-frontal cortex. The findings of this study suggest, first, passive heat exposure increases oxygen delivery in the pre-frontal cortex to maintain pre-frontal cortex oxygenation; second, there is no evidence of passive heat exposure in cognitive functioning in this study; and third, the greater increases of oxyhemoglobin in the pre-frontal cortex during cognitive functioning at the hottest condition suggests a recruitment of available neural resources or greater effort to maintain the same performance at the same level as when they felt thermally comfortable.

Spatial and temporal modeling of sub- and supercritical thermal energy storage

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

Tse, LA; Ganapathi, GB; Wirz, RE

2014-05-01

This paper describes a thermodynamic model that simulates the discharge cycle of a single-tank thermal energy storage (TES) system that can operate from the two-phase (liquid-vapor) to supercritical regimes for storage fluid temperatures typical of concentrating solar power plants. State-of-the-art TES design utilizes a two-tank system with molten nitrate salts; one major problem is the high capital cost of the salts (International Renewable Energy Agency, 2012). The alternate approach explored here opens up the use of low-cost fluids by considering operation at higher pressures associated with the two-phase and supercritical regimes. The main challenge to such a system is itsmore » high pressures and temperatures which necessitate a relatively high-cost containment vessel that represents a large fraction of the system capital cost. To mitigate this cost, the proposed design utilizes a single-tank TES system, effectively halving the required wall material. A single-tank approach also significantly reduces the complexity of the system in comparison to the two-tank systems, which require expensive pumps and external heat exchangers. A thermodynamic model is used to evaluate system performance; in particular it predicts the volume of tank wall material needed to encapsulate the storage fluid. The transient temperature of the tank is observed to remain hottest at the storage tank exit, which is beneficial to system operation. It is also shown that there is an optimum storage fluid loading that generates a given turbine energy output while minimizing the required tank wall material. Overall, this study explores opportunities to further improve current solar thermal technologies. The proposed single-tank system shows promise for decreasing the cost of thermal energy storage. (C) 2014 Elsevier Ltd. All rights reserved.« less

The Impact of Nonequilibrium Ionization on SDO/AIA and Hinode/EIS Observations of Impulsively Heated Plasmas

NASA Technical Reports Server (NTRS)

Klimchuk, James A.; Bradshaw, Stephen J.

2011-01-01

Most plasma diagnostics assume the emitting material is in a state of ionization equilibrium. For example, the AIA temperature response functions have been derived on this basis. The assumption is reasonable whenever the plasma is evolving slowly or is very dense, but these are not the conditions that apply during impulsive heating events. It is now widely believed that many coronal loops are bundles of unresolved strands that are heated quasi-randomly by nanoflares. Full blown flares are thought to have similar sub-structure. We have studied the importance of nonequilibrium effects in these circumstances by modeling nanoflare-heated loops and simulating their observation by AIA and the EIS spectrometer on Hinode. We find that the intensities of hot emission lines can be highly suppressed and that the net emission from the loop tends to be dominated by strands that have entered a slow cooling phase, well after the impulsive energy release has ended. The hottest strands are relatively invisible, both because they are tenuous and because they cool rapidly by thermal conduction. Thus, AIA channels that are normally thought of as being sensitive to hot plasma, such 131 and 94, are in fact frequently not able to detect the hot plasma that is present. The magnitude of the effect is case dependent. Great care must be exercised when using the standard temperature response functions in situations where nonequilibrium ionization is likely to be important.

Diversity of thermophiles in a Malaysian hot spring determined using 16S rRNA and shotgun metagenome sequencing.

PubMed

Chan, Chia Sing; Chan, Kok-Gan; Tay, Yea-Ling; Chua, Yi-Heng; Goh, Kian Mau

2015-01-01

The Sungai Klah (SK) hot spring is the second hottest geothermal spring in Malaysia. This hot spring is a shallow, 150-m-long, fast-flowing stream, with temperatures varying from 50 to 110°C and a pH range of 7.0-9.0. Hidden within a wooded area, the SK hot spring is continually fed by plant litter, resulting in a relatively high degree of total organic content (TOC). In this study, a sample taken from the middle of the stream was analyzed at the 16S rRNA V3-V4 region by amplicon metagenome sequencing. Over 35 phyla were detected by analyzing the 16S rRNA data. Firmicutes and Proteobacteria represented approximately 57% of the microbiome. Approximately 70% of the detected thermophiles were strict anaerobes; however, Hydrogenobacter spp., obligate chemolithotrophic thermophiles, represented one of the major taxa. Several thermophilic photosynthetic microorganisms and acidothermophiles were also detected. Most of the phyla identified by 16S rRNA were also found using the shotgun metagenome approaches. The carbon, sulfur, and nitrogen metabolism within the SK hot spring community were evaluated by shotgun metagenome sequencing, and the data revealed diversity in terms of metabolic activity and dynamics. This hot spring has a rich diversified phylogenetic community partly due to its natural environment (plant litter, high TOC, and a shallow stream) and geochemical parameters (broad temperature and pH range). It is speculated that symbiotic relationships occur between the members of the community.

The Statistics of Albedo and Heat Recirculation on Hot Exoplanets

NASA Astrophysics Data System (ADS)

Cowan, Nicolas B.; Agol, Eric

2011-03-01

If both the day-side and night-side effective temperatures of a planet can be measured, it is possible to estimate its Bond albedo, 0 < AB < 1, as well as its day-night heat redistribution efficiency, 0 < ɛ < 1. We attempt a statistical analysis of the albedo and redistribution efficiency for 24 transiting exoplanets that have at least one published secondary eclipse. For each planet, we show how to calculate a sub-stellar equilibrium temperature, T 0, and associated uncertainty. We then use a simple model-independent technique to estimate a planet's effective temperature from planet/star flux ratios. We use thermal secondary eclipse measurements—those obtained at λ>0.8 μm—to estimate day-side effective temperatures, T d, and thermal phase variations—when available—to estimate night-side effective temperature. We strongly rule out the "null hypothesis" of a single AB and ɛ for all 24 planets. If we allow each planet to have different parameters, we find that low Bond albedos are favored (AB < 0.35 at 1σ confidence), which is an independent confirmation of the low albedos inferred from non-detections of reflected light. Our sample exhibits a wide variety of redistribution efficiencies. When normalized by T 0, the day-side effective temperatures of the 24 planets describe a uni-modal distribution. The two biggest outliers are GJ 436b (abnormally hot) and HD 80606b (abnormally cool), and these are the only eccentric planets in our sample. The dimensionless quantity T d/T 0 exhibits no trend with the presence or absence of stratospheric inversions. There is also no clear trend between T d/T 0 and T 0. That said, the six planets with the greatest sub-stellar equilibrium temperatures (T > 2400 K) have low ɛ, as opposed to the 18 cooler planets, which show a variety of recirculation efficiencies. This hints that the very hottest transiting giant planets are qualitatively different from the merely hot Jupiters. We propose an explanation of this trend based on how a planet's radiative and advective times scale with temperature: both timescales are expected to be shorter for hotter planets, but the temperature dependence of the radiative timescale is stronger, leading to decreased heat recirculation efficiency.

Shear heating and metamorphism in subduction zones, 1. Thermal models

NASA Astrophysics Data System (ADS)

Kohn, M. J.; Castro, A. E.; Spear, F. S.

2017-12-01

Popular thermal-mechanical models of modern subduction systems are 100-500 °C colder at c. 50 km depth than pressure-temperature (P-T) conditions determined from exhumed metamorphic rocks. This discrepancy has been ascribed by some to profound bias in the rock record, i.e. metamorphic rocks reflect only anomalously warm subduction, not normal subduction. Accurately inferring subduction zone thermal structure, whether from models or rocks, is crucial for predicting depths of seismicity, fluid release, and sub-arc melting conditions. Here, we show that adding realistic shear stresses to thermal models implies P-T conditions quantitatively consistent with those recorded by exhumed metamorphic rocks, suggesting that metamorphic rock P-T conditions are not anomalously warm. Heat flow measurements from subduction zone fore-arcs typically indicate effective coefficients of friction (µ) ranging from 0.025 to 0.1. We included these coefficients of friction in analytical models of subduction zone interface temperatures. Using global averages of subducting plate age (50 Ma), subduction velocity (6 cm/yr), and subducting plate geometry (central Chile), temperatures at 50 km depth (1.5 GPa) increase by c. 200 °C for µ=0.025 to 700 °C for µ=0.1. However, at high temperatures, thermal softening will reduce frictional heating, and temperatures will not increase as much with depth. Including initial weakening of materials ranging from wet quartz (c. 300 °C) to diabase (c. 600 °C) in the analytical models produces concave-upward P-T distributions on P-T diagrams, with temperatures c. 100 to 500 °C higher than models with no shear heating. The absolute P-T conditions and concave-upward shape of the shear-heating + thermal softening models almost perfectly matches the distribution of P-T conditions derived from a compilation of exhumed metamorphic rocks. Numerical models of modern subduction zones that include shear heating also overlap metamorphic data. Thus, excepting the very hottest examples, exhumed metamorphic rocks represent the products of normal, not anomalous, subduction. Consequently numerous geochemical, petrologic, and geophysical interpretations that have been founded on models that lack shear heating must be re-evaluated.

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

Perez-Becker, Daniel; Showman, Adam P.

Infrared light curves of transiting hot Jupiters present a trend in which the atmospheres of the hottest planets are less efficient at redistributing the stellar energy absorbed on their daysides—and thus have a larger day-night temperature contrast—than colder planets. To this day, no predictive atmospheric model has been published that identifies which dynamical mechanisms determine the atmospheric heat redistribution efficiency on tidally locked exoplanets. Here we present a shallow-water model of the atmospheric dynamics on synchronously rotating planets that explains why heat redistribution efficiency drops as stellar insolation rises. Our model shows that planets with weak friction and weak irradiationmore » exhibit a banded zonal flow with minimal day-night temperature differences, while models with strong irradiation and/or strong friction exhibit a day-night flow pattern with order-unity fractional day-night temperature differences. To interpret the model, we develop a scaling theory which shows that the timescale for gravity waves to propagate horizontally over planetary scales, τ{sub wave}, plays a dominant role in controlling the transition from small to large temperature contrasts. This implies that heat redistribution is governed by a wave-like process, similar to the one responsible for the weak temperature gradients in the Earth's tropics. When atmospheric drag can be neglected, the transition from small to large day-night temperature contrasts occurs when τ{sub wave}∼√(τ{sub rad}/Ω), where τ{sub rad} is the radiative relaxation time and Ω is the planetary rotation frequency. Alternatively, this transition criterion can be expressed as τ{sub rad} ∼ τ{sub vert}, where τ{sub vert} is the timescale for a fluid parcel to move vertically over the difference in day-night thickness. These results subsume the more widely used timescale comparison for estimating heat redistribution efficiency between τ{sub rad} and the horizontal day-night advection timescale, τ{sub adv}. Only because τ{sub adv} ∼ τ{sub vert} for hot Jupiters does the commonly assumed timescale comparison between τ{sub rad} and τ{sub adv} yield approximately correct predictions for the heat redistribution efficiency.« less

Oxygen fugacity of gases and rocks from Momotombo Volcano, Nicaragua: Application to volcanological monitoring

NASA Astrophysics Data System (ADS)

Benhamou, G.; Allard, P.; Sabroux, J. C.; Vitter, G.; Dajlevic, D.; Creusot, A.

1988-12-01

The oxygen fugacity (fO2) and the fO2 versus T°C relationship of high-temperature (600°-860°C) gas emissions from Momotombo volcano, Nicaragua, was determined from both field electrochemical measurements (electrolytic cell assembly) and thermodynamic computations on gas samples collected between 1978 and 1985. It was then compared with the intrinsic fO2 of fresh and altered lavas from the last eruption (1905), as measured between 500° and 1100°C in laboratory. The electrochemical results show that the oxygen fugacity of Momotombo fumaroles, at equivalent temperature, is much higher than that of the fresh 1905 lava (˜FMQ buffer) and closer to that of their altered wall rocks (˜FMQ buffer). The equilibrium O2 fugacities calculated from the chemistry of gas samples confirm this pattern. However, they suggest that the gas mixtures preserve the (variable) memory of a higher thermal equilibrium achieved at depth, under temperature and fO2 conditions of up to 1050°C and 10-9.0 atm, respectively, which correspond to the cross over between the fO2-T gas and lava trends. These data thus support the idea that Momotombo volcanic gases, released in a period of increasing activity, escape from a shallow magma body before suffering a variable oxidation during their ascent through both unbuffered cooling and reactions with environmental fluids and rocks. This late oxidation is weaker at central fumaroles than at peripherical ones. While between 1978 and 1985 the temperature of the hottest fumarole increased from 750° to 865°-900°C, the equilibrium fO2 of the gas decreased by nearly one order of magnitude (at comparable equilibrium temperature). Such an evolution presumably reflects an increasing connection between the surface exhalations and the magma degassing at depth along with time. This work underlines the possibility of monitoring the processes of magma ascent and gas-magma separation within a volcano before an eruption by continuously recording the changes of both oxygen fugacity and temperature in hot fumaroles.

Testing alternative models of climate-mediated extirpations.

PubMed

Beever, Erik A; Ray, Chris; Mote, Philip W; Wilkening, Jennifer L

2010-01-01

Biotic responses to climate change will vary among taxa and across latitudes, elevational gradients, and degrees of insularity. However, due to factors such as phenotypic plasticity, ecotypic variation, and evolved tolerance to thermal stress, it remains poorly understood whether losses should be greatest in populations experiencing the greatest climatic change or living in places where the prevailing climate is closest to the edge of the species' bioclimatic envelope (e.g., at the hottest, driest sites). Research on American pikas (Ochotona princeps) in montane areas of the Great Basin during 1994-1999 suggested that 20th-century population extirpations were predicted by a combination of biogeographic, anthropogenic, and especially climatic factors. Surveys during 2005-2007 documented additional extirpations and within-site shifts of pika distributions at remaining sites. To evaluate the evidence in support of alternative hypotheses involving effects of thermal stress on pikas, we placed temperature sensors at 156 locations within pika habitats in the vicinity of 25 sites with historical records of pikas in the Basin. We related these time series of sensor data to data on ambient temperature from weather stations within the Historical Climate Network. We then used these highly correlated relationships, combined with long-term data from the same weather stations, to hindcast temperatures within pika habitats from 1945 through 2006. To explain patterns of loss, we posited three alternative classes of direct thermal stress: (1) acute cold stress (number of days below a threshold temperature); (2) acute heat stress (number of days above a threshold temperature); and (3) chronic heat stress (average summer temperature). Climate change was defined as change in our thermal metrics between two 31-yr periods: 1945-1975 and 1976-2006. We found that patterns of persistence were well predicted by metrics of climate. Our best models suggest some effects of climate change; however, recent and long-term metrics of chronic heat stress and acute cold stress, neither previously recognized as sources of stress for pikas, were some of the best predictors of pika persistence. Results illustrate that extremely rapid distributional shifts can be explained by climatic influences and have implications for conservation topics such as reintroductions and early-warning indicators.

Testing alternative models of climate-mediated extirpations

USGS Publications Warehouse

Beever, E.A.; Chris, R.A.Y.; Mote, P.W.; Wilkening, J.L.

2010-01-01

Biotic responses to climate change will vary among taxa and across latitudes, elevational gradients, and degrees of insularity. However, due to factors such as phenotypic plasticity, ecotypic variation, and evolved tolerance to thermal stress, it remains poorly understood whether losses should be greatest in populations experiencing the greatest climatic change or living in places where the prevailing climate is closest to the edge of the species' bioclimatic envelope (e.g., at the hottest, driest sites). Research on American pikas (Ochotona princeps) in montane areas of the Great Basin during 1994-1999 suggested that 20th-century population extirpations were predicted by a combination of biogeographic, anthropogenic, and especially climatic factors. Surveys during 2005-2007 documented additional extirpations and within-site shifts of pika distributions at remaining sites. To evaluate the evidence in support of alternative hypotheses involving effects of thermal stress on pikas, we placed temperature sensors at 156 locations within pika habitats in the vicinity of 25 sites with historical records of pikas in the Basin. We related these time series of sensor data to data on ambient temperature from weather stations within the Historical Climate Network. We then used these highly correlated relationships, combined with long-term data from the same weather stations, to hindcast temperatures within pika habitats from 1945 through 2006. To explain patterns of loss, we posited three alternative classes of direct thermal stress: (1) acute cold stress (number of days below a threshold temperature); (2) acute heat stress (number of days above a threshold, temperature); and. (3) chronic heat stress (average summer temperature). Climate change was defined as change in our thermal metrics between two 31-y.r periods: 1945-1975 and 1976-2006. We found that patterns of persistence were well predicted by metrics of climate. Our best models suggest some effects of climate change; however, recent and long-term metrics of chronic heat stress and acute cold stress, neither previously recognized as sources of stress for pikas, were some of the best predictors of pika persistence. Results illustrate that extremely rapid distributional shifts can be explained by climatic influences and have implications for conservation topics such as reintroductions and early-warning indicators. ?? 2010 by the Ecological society of America.

Petroleum Independence: A Business Case and Strategy

DTIC Science & Technology

2006-04-14

examples of this are the OPEC increases in 1973-74, Iranian Revolution of 1979, 1990 Iraqi invasion of Kuwait, and the Katrina hurricane disaster in 2005...retreat of glaciers.88 More hurricanes , droughts, and tropical diseases are likely caused by the fact that our last decade was reported as the hottest in...filelibrary/ Katrin aSlides.pdf ; Internet; accessed on December 7, 2005. Economic 37 lower-priced energy, and improved energy efficiencies. Regardless of

Database Reorganization in Parallel Disk Arrays with I/O Service Stealing

NASA Technical Reports Server (NTRS)

Zabback, Peter; Onyuksel, Ibrahim; Scheuermann, Peter; Weikum, Gerhard

1996-01-01

We present a model for data reorganization in parallel disk systems that is geared towards load balancing in an environment with periodic access patterns. Data reorganization is performed by disk cooling, i.e. migrating files or extents from the hottest disks to the coldest ones. We develop an approximate queueing model for determining the effective arrival rates of cooling requests and discuss its use in assessing the costs versus benefits of cooling.

Environmental Assessment for Irrigation System for the Golf Course

DTIC Science & Technology

2007-01-01

woodland species oak, maple, willow, bald cypress, sweet gum and loblolly pine. Vegetation located in the project area is Bermuda grass. 3.2.6...in an area of improved grounds. A sod cutter would be used to remove existing Bermuda grass on the course for placement of pipes and sprinklers...The same Bermuda grass would be replaced over the pipes when installation is complete. The grass would then be watered during the hottest summer

White Dwarf Model Atmospheres: Synthetic Spectra for Supersoft Sources

NASA Astrophysics Data System (ADS)

Rauch, Thomas

2013-01-01

The Tübingen NLTE Model-Atmosphere Package (TMAP) calculates fully metal-line blanketed white dwarf model atmospheres and spectral energy distributions (SEDs) at a high level of sophistication. Such SEDs are easily accessible via the German Astrophysical Virtual Observatory (GAVO) service TheoSSA. We discuss applications of TMAP models to (pre) white dwarfs during the hottest stages of their stellar evolution, e.g. in the parameter range of novae and supersoft sources.

1981 Hartwell Lake Water Quality Study.

DTIC Science & Technology

1982-09-01

located approximately eight kilometers from stabions 2, 3, and 8. The highest and lowest temp- eratures were 101 and 11 farenheit (F) during the hottest...stations and months for ORP measurements are given in Figures B-21 through B-23. There was absolutely no pattern to the August values for both...all lake stations (excluding Station 9), but which was most pronounced in the cove where denisties dropped to zero , is unknown. Physical and chemical

A real time study on condition monitoring of distribution transformer using thermal imager

NASA Astrophysics Data System (ADS)

Mariprasath, T.; Kirubakaran, V.

2018-05-01

The transformer is one of the critical apparatus in the power system. At any cost, a few minutes of outages harshly influence the power system. Hence, prevention-based maintenance technique is very essential. The continuous conditioning and monitoring technology significantly increases the life span of the transformer, as well as reduces the maintenance cost. Hence, conditioning and monitoring of transformer's temperature are very essential. In this paper, a critical review has been made on various conditioning and monitoring techniques. Furthermore, a new method, hot spot indication technique, is discussed. Also, transformer's operating condition is monitored by using thermal imager. From the thermal analysis, it is inferred that major hotspot locations are appearing at connection lead out; also, the bushing of the transformer is the very hottest spot in transformer, so monitoring the level of oil is essential. Alongside, real time power quality analysis has been carried out using the power analyzer. It shows that industrial drives are injecting current harmonics to the distribution network, which causes the power quality problem on the grid. Moreover, the current harmonic limit has exceeded the IEEE standard limit. Hence, the adequate harmonics suppression technique is need an hour.

Hair cycle in dogs with different hair types in a tropical region of Brazil.

PubMed

Favarato, Evandro S; Conceição, Lissandro Gonçalves

2008-02-01

Hair cycle activity has been extensively studied in humans, sheep and laboratory animals, but there is a lack of information in dogs. Besides varying according to species, breed, sex and general health, hair growth is mainly affected by climatic variations. The aim of the study was to evaluate the follicle activity in three breeds of dogs with different hair types, in the city of Viçosa, Minas Gerais (latitude 20 degrees 45'S), Brazil. Twenty-one male dogs of boxer, labrador and schnauzer breeds were trichographically analysed monthly over 12 consecutive months. Hair percentage of telogen and anagen hairs at the different stages of the hair cycle in boxers and labradors was not significantly different, but both differed from the schnauzers. A significant correlation between hair follicle cycle and environmental temperature and photoperiod was noted in the boxers and labradors. In these breeds, a larger number of telogen hairs were observed during the hottest months of the year, and an increase in anagen hairs during the coldest months. The mean percentage of telogen hairs was 93, 90 and 55.3% for boxer, labrador and schnauzer, respectively.

Mycological flora of the Hammams, traditional Turkish bath.

PubMed

Goksugur, Nadir; Karabay, Oguz; Kocoglu, Esra

2006-09-01

Traditional Turkish baths, Hammams, occupy a prominent place in public health in history and at present. It is well-known that baths are major sources of fungal skin infections, but according to our knowledge fungal flora of Turkish Hammams was not defined yet. In Bolu, Turkey, two Hammams were open to public and for detecting fungal flora, we collected 209 samples from different part of floors, tools and screened for the fungal pathogens. From floors of the dressing rooms, Trichophyton rubrum and Candida albicans; from slippers T. rubrum, T. mentagrophytes, Epidermophyton floccosum, Candida albicans and C. tropicalis were isolated. While we could not isolate any dermatophyte species and yeasts from the vicinity of the bath windows and walls of baths, Aspergillus spp. and Penicillium spp. were isolated from the same locations. Samples taken from marble floors of baths, central massage platforms (hottest part of the Hammam) and towels did not show any fungal growth. This report reveals that components of the Turkish Hammams have low risk for fungal contamination as a result of frequent cleaning and environmental high temperature. But shared tools like slippers were found to be an important source of fungal contamination.

Hot days induced by precipitation deficits at the global scale

PubMed Central

Mueller, Brigitte; Seneviratne, Sonia I.

2012-01-01

Global warming increases the occurrence probability of hot extremes, and improving the predictability of such events is thus becoming of critical importance. Hot extremes have been shown to be induced by surface moisture deficits in some regions. In this study, we assess whether such a relationship holds at the global scale. We find that wide areas of the world display a strong relationship between the number of hot days in the regions’ hottest month and preceding precipitation deficits. The occurrence probability of an above-average number of hot days is over 70% after precipitation deficits in most parts of South America as well as the Iberian Peninsula and Eastern Australia, and over 60% in most of North America and Eastern Europe, while it is below 30–40% after wet conditions in these regions. Using quantile regression analyses, we show that the impact of precipitation deficits on the number of hot days is asymmetric, i.e. extreme high numbers of hot days are most strongly influenced. This relationship also applies to the 2011 extreme event in Texas. These findings suggest that effects of soil moisture-temperature coupling are geographically more widespread than commonly assumed. PMID:22802672

Farmers perceptions on climate change in lowland and highland vegetable production centers of South Sulawesi, Indonesia

NASA Astrophysics Data System (ADS)

Adiyoga, W.

2018-02-01

A survey was carried out in South Sulawesi, Indonesia interviewing 220 vegetable farmers. It was aimed at examining the vegetable farmers’ perception of climate change and assessing the consistency of farmers’ perception with available time series meteorological data. Results suggest that meteorological data analysis is in agreement with farmers’ perception regarding faster start, longer ending, and longer duration of rainy season. Further data analysis supports the claim of most farmers who perceive the occurrence of increasing air temperature, changing or shifting of the hottest and coldest month. Most respondents also suggest that climate change has affected vegetable farm yield and profitability. Other respondents even predict that climate change may affect the quality of life of their future descendants. Meanwhile, significant number of farmers is quite optimistic that they can cope with climate change problems through adaptation strategy. However, the attitude of farmers towards climate change is mostly negative as compared to positive or neutral feeling. Informative and educational campaign should be continuously carried out to encourage farmers in developing positive attitude or positive thinking towards climate change. Positive attitude may eventually lead to constructive behavior in selecting and implementing adaptation options.

Response of Urban Systems to Climate Change in Europe: Heat Stress Exposure and the Effect on Human Health

NASA Astrophysics Data System (ADS)

Stevens, Catherine; Thomas, Bart; Grommen, Mart

2015-04-01

Climate change is driven by global processes such as the global ocean circulation and its variability over time leading to changing weather patterns on regional scales as well as changes in the severity and occurrence of extreme events such as heavy rain- and windstorms, floods, drought, heat waves, etc. The summer 2003 European heat wave was the hottest summer on record in Europe over the past centuries leading to health crises in several countries like France and caused up to 70.000 excess deaths over four months in Central and Western Europe. The main risks induced by global climate change in urbanised areas are considered to be overheating and resulting health effects, increased exposure to flood events, increased damage losses from extreme weather conditions but also shortages in the provision of life-sustaining services. Moreover, the cities themselves create specific or inherent risks and urban adaptation is often very demanding. As most of Europe's inhabitants live in cities, it is of particular relevance to examine the impact of climate variability on urban areas and their populations. The present study focusses on the identification of heat stress variables related to human health and the extraction of this information by processing daily temperature statistics of local urban climate simulations over multiple timeframes of 20 years and three different European cities based on recent, near future and far future global climate predictions. The analyses have been conducted in the framework of the NACLIM FP7 project funded by the European Commission involving local stakeholders such as the cities of Antwerp (Belgium), Berlin (Germany) and Almada (Portugal) represented by different climate and urban characteristics. Apart from the urban-rural temperature increment (urban heat island effect), additional heat stress parameters such as the average number of heat wave days together with their duration and intensities have been covered during this research. In a subsequent step, the heat stress variables are superposed on relevant socio-economic datasets targeting total population and its distribution per age class as well as vulnerable institutions such as hospitals, schools, rest homes and child/day care facilities in order to generate heat stress exposure maps for each use case city and various climate, urban planning and mitigation scenarios. The specifications and requirements for the various scenarios have been consolidated in close collaboration with the local stakeholders during dedicated end-users workshops. The results of this study will allow urban planners and policy makers facing the challenges of climate change and develop sound strategies for evolving towards sustainable and climate resilient cities.

Ultra-Compact Motor Controller

NASA Technical Reports Server (NTRS)

Townsend, William T.; Crowell, Adam; Hauptman, Traveler; Pratt, Gill Andrews

2012-01-01

This invention is an electronically commutated brushless motor controller that incorporates Hall-array sensing in a small, 42-gram package that provides 4096 absolute counts per motor revolution position sensing. The unit is the size of a miniature hockey puck, and is a 44-pin male connector that provides many I/O channels, including CANbus, RS-232 communications, general-purpose analog and digital I/O (GPIO), analog and digital Hall inputs, DC power input (18-90 VDC, 0-l0 A), three-phase motor outputs, and a strain gauge amplifier. This controller replaces air cooling with conduction cooling via a high-thermal-conductivity epoxy casting. A secondary advantage of the relatively good heat conductivity that comes with ultra-small size is that temperature differences within the controller become smaller, so that it is easier to measure the hottest temperature in the controller with fewer temperature sensors, or even one temperature sensor. Another size-sensitive design feature is in the approach to electrical noise immunity. At a very small size, where conduction paths are much shorter than in conventional designs, the ground becomes essentially isopotential, and so certain (space-consuming) electrical noise control components become unnecessary, which helps make small size possible. One winding-current sensor, applied to all of the windings in fast sequence, is smaller and wastes less power than the two or more sensors conventionally used to sense and control winding currents. An unexpected benefit of using only one current sensor is that it actually improves the precision of current control by using the "same" sensors to read each of the three phases. Folding the encoder directly into the controller electronics eliminates a great deal of redundant electronics, packaging, connectors, and hook-up wiring. The reduction of wires and connectors subtracts substantial bulk and eliminates their role in behaving as EMI (electro-magnetic interference) antennas. A shared knowledge by each motor controller of the state of all the motors in the system at 500 Hz also allows parallel processing of higher-level kinematic matrix calculations.

Effect of tidal regime on the thermal tolerance of the marine gastropod Lunella smaragda (Gmelin 1791).

PubMed

Mortensen, B J D; Dunphy, B J

2016-08-01

The tidal cycle around New Zealand results in spring low tides consistently occurring during the hottest part of the day (mid-afternoon) in north-eastern New Zealand, and during the cooler dawn/dusk periods in the north-west of the country. We hypothesised that due to mid-afternoon spring low tides, intertidal populations residing at north-eastern sites would show greater thermotolerance than their north-west conspecifics. To test this we used the marine gastropod, Lunella smaragda, which were collected from sites on both the East and West coasts of the Auckland region and exposed to an acute heat shock. Thermotolerance was measured as survivorship (LT50), drop down time (time to heat coma) and thermal stability of the anaerobic energy producing enzyme Tauropine dehydrogenase. Furthermore, temperature loggers were deployed at each site so as to record and compare thermal regimes among sites. A strong temperature spike associated with spring low tide was found at all sites, and maximal temperatures of all East coast sites were higher than West coast sites (in some case by up to 10°C). In terms of thermotolerance, mortality of L. smaragda occurred at 42°C leading to 100% mortality at 45°C. However, comparison of LT50 showed snails were equally thermotolerant regardless of site of collection. Similar results were found in TDH thermal stability with animals from all sites showing an approximately 80% decrease in enzyme activity after 10min exposure to 42°C. Whilst drop down times were different among sites these were correlated with animal size as opposed to site of collection. Thus, East coast populations of L. smaragda appear no more thermotolerant than their West coast counterparts. Such a result is concerning as maximal temperatures at East coast sites already exceed the LT50 values of L. smaragda recorded in the lab suggesting these populations have less of a thermal safety margin. Copyright © 2016 Elsevier Ltd. All rights reserved.

Alternative Fuels Data Center: Hydrogen Production and Distribution

Science.gov Websites

created by reacting natural gas with high-temperature steam. The carbon monoxide is reacted with water to synthesis gas can also be created by reacting coal or biomass with high-temperature steam and oxygen in a : Renewable liquid fuels, such as ethanol, are reacted with high-temperature steam to produce hydrogen near

Obama Calls for More Action on Climate Change During State of the Union Address

NASA Astrophysics Data System (ADS)

Showstack, Randy

2013-02-01

President Barack Obama called for "meaningful progress" on climate change during his State of the Union address on 12 February, saying that "for the sake of our children and our future, we must do more to combat climate change." Noting that "the 12 hottest years on record have all come in the last 15," he said that there could be meaningful progress on the issue while also driving economic growth.

More Than Just Monkey Business: What the Primate Microbiome Might Say About the Human One.

PubMed

Berglund, Jennifer

2016-01-01

The science of the microbiome is arguably one of the hottest topics in medicine, and rightfully so. A deeper understanding of the ecology of the flora in our bodies is providing revolutionary insight beyond the simple form and function of our major parts. This new frontier is dauntingly complex, and most studies focus on details, failing to place these microbial ecosystems within the larger context of evolutionary time and environment.

Archean komatiite volcanism controlled by the evolution of early continents.

PubMed

Mole, David R; Fiorentini, Marco L; Thebaud, Nicolas; Cassidy, Kevin F; McCuaig, T Campbell; Kirkland, Christopher L; Romano, Sandra S; Doublier, Michael P; Belousova, Elena A; Barnes, Stephen J; Miller, John

2014-07-15

The generation and evolution of Earth's continental crust has played a fundamental role in the development of the planet. Its formation modified the composition of the mantle, contributed to the establishment of the atmosphere, and led to the creation of ecological niches important for early life. Here we show that in the Archean, the formation and stabilization of continents also controlled the location, geochemistry, and volcanology of the hottest preserved lavas on Earth: komatiites. These magmas typically represent 50-30% partial melting of the mantle and subsequently record important information on the thermal and chemical evolution of the Archean-Proterozoic Earth. As a result, it is vital to constrain and understand the processes that govern their localization and emplacement. Here, we combined Lu-Hf isotopes and U-Pb geochronology to map the four-dimensional evolution of the Yilgarn Craton, Western Australia, and reveal the progressive development of an Archean microcontinent. Our results show that in the early Earth, relatively small crustal blocks, analogous to modern microplates, progressively amalgamated to form larger continental masses, and eventually the first cratons. This cratonization process drove the hottest and most voluminous komatiite eruptions to the edge of established continental blocks. The dynamic evolution of the early continents thus directly influenced the addition of deep mantle material to the Archean crust, oceans, and atmosphere, while also providing a fundamental control on the distribution of major magmatic ore deposits.

Archean komatiite volcanism controlled by the evolution of early continents

PubMed Central

Mole, David R.; Fiorentini, Marco L.; Thebaud, Nicolas; Cassidy, Kevin F.; McCuaig, T. Campbell; Kirkland, Christopher L.; Romano, Sandra S.; Doublier, Michael P.; Belousova, Elena A.; Barnes, Stephen J.; Miller, John

2014-01-01

The generation and evolution of Earth’s continental crust has played a fundamental role in the development of the planet. Its formation modified the composition of the mantle, contributed to the establishment of the atmosphere, and led to the creation of ecological niches important for early life. Here we show that in the Archean, the formation and stabilization of continents also controlled the location, geochemistry, and volcanology of the hottest preserved lavas on Earth: komatiites. These magmas typically represent 50–30% partial melting of the mantle and subsequently record important information on the thermal and chemical evolution of the Archean–Proterozoic Earth. As a result, it is vital to constrain and understand the processes that govern their localization and emplacement. Here, we combined Lu-Hf isotopes and U-Pb geochronology to map the four-dimensional evolution of the Yilgarn Craton, Western Australia, and reveal the progressive development of an Archean microcontinent. Our results show that in the early Earth, relatively small crustal blocks, analogous to modern microplates, progressively amalgamated to form larger continental masses, and eventually the first cratons. This cratonization process drove the hottest and most voluminous komatiite eruptions to the edge of established continental blocks. The dynamic evolution of the early continents thus directly influenced the addition of deep mantle material to the Archean crust, oceans, and atmosphere, while also providing a fundamental control on the distribution of major magmatic ore deposits. PMID:24958873

Deep Stimulation at Newberry Volcano EGS Demonstration

NASA Astrophysics Data System (ADS)

Grasso, K.; Cladouhos, T. T.; Petty, S.; Garrison, G. H.; Nordin, Y.; Uddenberg, M.; Swyer, M.

2014-12-01

The Newberry Volcano EGS Demonstration is a 5 year field project designed to demonstrate recent technological advances for engineered geothermal systems (EGS) development. Advances in reservoir stimulation, diverter, and monitoring are being tested in a hot (>300 C), dry well (NWG 55-29) drilled in 2008. These technologies could reduce the cost of electrical power generation. The project began in 2010 with two years of permitting, technical planning, and development of a project-specific Induced Seismicity Mitigation Plan (ISMP), and is funded in part by the Department of Energy. In 2012, the well was hydraulically stimulated with water at pressures below the principle stress for 7 weeks, resulting in hydroshearing. The depth of stimulation was successfully shifted by injection of two pills of Thermally-degradable Zonal Isolation Materials (TZIMs). Injectivity changes, thermal profiles and seismicity indicate that fracture permeability in well NWG 55-29 was enhanced during stimulation. This work successfully demonstrated the viability of large-volume (40,000 m3), low-pressure stimulation coupled with non-mechanical diverter technology, and microseismic monitoring for reservoir mapping. Further analysis and field testing in 2013 indicates further stimulation will be required in order to develop an economically viable reservoir, and is scheduled in 2014. The 2014 stimulation will use improved stimulation and monitoring equipment, better knowledge based on 2012 outcomes, and create a deep EGS reservoir in the hottest part of the wellbore.

Functional and Physical Outcomes following Use of a Flexible CO2 Laser Fiber and Bipolar Electrocautery in Close Proximity to the Rat Sciatic Nerve with Correlation to an In Vitro Thermal Profile Model

PubMed Central

Robinson, A. M.; Fishman, A. J.; Bendok, B. R.; Richter, C.-P.

2015-01-01

This study compared functional and physical collateral damage to a nerve when operating a Codman MALIS Bipolar Electrosurgical System CMC-III or a CO2 laser coupled to a laser, with correlation to an in vitro model of heating profiles created by the devices in thermochromic ink agarose. Functional damage of the rat sciatic nerve after operating the MALIS or CO2 laser at various power settings and proximities to the nerve was measured by electrically evoked nerve action potentials, and histology of the nerve was used to assess physical damage. Thermochromic ink dissolved in agarose was used to model the spatial and temporal profile of the collateral heating zone of the electrosurgical system and the laser ablation cone. We found that this laser can be operated at 2 W directly above the nerve with minimal damage, while power settings of 5 W and 10 W resulted in acute functional and physical nerve damage, correlating with the maximal heating cone in the thermochromic ink model. MALIS settings up to 40 (11 W) did not result in major functional or physical nerve damage until the nerve was between the forceps tips, correlating with the hottest zone, localized discretely between the tips. PMID:25699266

A giant planet undergoing extreme-ultraviolet irradiation by its hot massive-star host.

PubMed

Gaudi, B Scott; Stassun, Keivan G; Collins, Karen A; Beatty, Thomas G; Zhou, George; Latham, David W; Bieryla, Allyson; Eastman, Jason D; Siverd, Robert J; Crepp, Justin R; Gonzales, Erica J; Stevens, Daniel J; Buchhave, Lars A; Pepper, Joshua; Johnson, Marshall C; Colon, Knicole D; Jensen, Eric L N; Rodriguez, Joseph E; Bozza, Valerio; Novati, Sebastiano Calchi; D'Ago, Giuseppe; Dumont, Mary T; Ellis, Tyler; Gaillard, Clement; Jang-Condell, Hannah; Kasper, David H; Fukui, Akihiko; Gregorio, Joao; Ito, Ayaka; Kielkopf, John F; Manner, Mark; Matt, Kyle; Narita, Norio; Oberst, Thomas E; Reed, Phillip A; Scarpetta, Gaetano; Stephens, Denice C; Yeigh, Rex R; Zambelli, Roberto; Fulton, B J; Howard, Andrew W; James, David J; Penny, Matthew; Bayliss, Daniel; Curtis, Ivan A; DePoy, D L; Esquerdo, Gilbert A; Gould, Andrew; Joner, Michael D; Kuhn, Rudolf B; Labadie-Bartz, Jonathan; Lund, Michael B; Marshall, Jennifer L; McLeod, Kim K; Pogge, Richard W; Relles, Howard; Stockdale, Christopher; Tan, T G; Trueblood, Mark; Trueblood, Patricia

2017-06-22

The amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extrasolar planets now known, only six have been found that transit hot, A-type stars (with temperatures of 7,300-10,000 kelvin), and no planets are known to transit the even hotter B-type stars. For example, WASP-33 is an A-type star with a temperature of about 7,430 kelvin, which hosts the hottest known transiting planet, WASP-33b (ref. 1); the planet is itself as hot as a red dwarf star of type M (ref. 2). WASP-33b displays a large heat differential between its dayside and nightside, and is highly inflated-traits that have been linked to high insolation. However, even at the temperature of its dayside, its atmosphere probably resembles the molecule-dominated atmospheres of other planets and, given the level of ultraviolet irradiation it experiences, its atmosphere is unlikely to be substantially ablated over the lifetime of its star. Here we report observations of the bright star HD 195689 (also known as KELT-9), which reveal a close-in (orbital period of about 1.48 days) transiting giant planet, KELT-9b. At approximately 10,170 kelvin, the host star is at the dividing line between stars of type A and B, and we measure the dayside temperature of KELT-9b to be about 4,600 kelvin. This is as hot as stars of stellar type K4 (ref. 5). The molecules in K stars are entirely dissociated, and so the primary sources of opacity in the dayside atmosphere of KELT-9b are probably atomic metals. Furthermore, KELT-9b receives 700 times more extreme-ultraviolet radiation (that is, with wavelengths shorter than 91.2 nanometres) than WASP-33b, leading to a predicted range of mass-loss rates that could leave the planet largely stripped of its envelope during the main-sequence lifetime of the host star.

Modeling behavioral thermoregulation in a climate change sentinel.

PubMed

Moyer-Horner, Lucas; Mathewson, Paul D; Jones, Gavin M; Kearney, Michael R; Porter, Warren P

2015-12-01

When possible, many species will shift in elevation or latitude in response to rising temperatures. However, before such shifts occur, individuals will first tolerate environmental change and then modify their behavior to maintain heat balance. Behavioral thermoregulation allows animals a range of climatic tolerances and makes predicting geographic responses under future warming scenarios challenging. Because behavioral modification may reduce an individual's fecundity by, for example, limiting foraging time and thus caloric intake, we must consider the range of behavioral options available for thermoregulation to accurately predict climate change impacts on individual species. To date, few studies have identified mechanistic links between an organism's daily activities and the need to thermoregulate. We used a biophysical model, Niche Mapper, to mechanistically model microclimate conditions and thermoregulatory behavior for a temperature-sensitive mammal, the American pika (Ochotona princeps). Niche Mapper accurately simulated microclimate conditions, as well as empirical metabolic chamber data for a range of fur properties, animal sizes, and environmental parameters. Niche Mapper predicted pikas would be behaviorally constrained because of the need to thermoregulate during the hottest times of the day. We also showed that pikas at low elevations could receive energetic benefits by being smaller in size and maintaining summer pelage during longer stretches of the active season under a future warming scenario. We observed pika behavior for 288 h in Glacier National Park, Montana, and thermally characterized their rocky, montane environment. We found that pikas were most active when temperatures were cooler, and at sites characterized by high elevations and north-facing slopes. Pikas became significantly less active across a suite of behaviors in the field when temperatures surpassed 20°C, which supported a metabolic threshold predicted by Niche Mapper. In general, mechanistic predictions and empirical observations were congruent. This research is unique in providing both an empirical and mechanistic description of the effects of temperature on a mammalian sentinel of climate change, the American pika. Our results suggest that previously underinvestigated characteristics, specifically fur properties and body size, may play critical roles in pika populations' response to climate change. We also demonstrate the potential importance of considering behavioral thermoregulation and microclimate variability when predicting animal responses to climate change.

Stainless steel corrosion by molten nitrates : analysis and lessons learned.

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

Kruizenga, Alan Michael

2011-09-01

A secondary containment vessel, made of stainless 316, failed due to severe nitrate salt corrosion. Corrosion was in the form of pitting was observed during high temperature, chemical stability experiments. Optical microscopy, scanning electron microscopy and energy dispersive spectroscopy were all used to diagnose the cause of the failure. Failure was caused by potassium oxide that crept into the gap between the primary vessel (alumina) and the stainless steel vessel. Molten nitrate solar salt (89% KNO{sub 3}, 11% NaNO{sub 3} by weight) was used during chemical stability experiments, with an oxygen cover gas, at a salt temperature of 350-700 C.more » Nitrate salt was primarily contained in an alumina vessel; however salt crept into the gap between the alumina and 316 stainless steel. Corrosion occurred over a period of approximately 2000 hours, with the end result of full wall penetration through the stainless steel vessel; see Figures 1 and 2 for images of the corrosion damage to the vessel. Wall thickness was 0.0625 inches, which, based on previous data, should have been adequate to avoid corrosion-induced failure while in direct contact with salt temperature at 677 C (0.081-inch/year). Salt temperatures exceeding 650 C lasted for approximately 14 days. However, previous corrosion data was performed with air as the cover gas. High temperature combined with an oxygen cover gas obviously drove corrosion rates to a much higher value. Corrosion resulted in the form of uniform pitting. Based on SEM and EDS data, pits contained primarily potassium oxide and potassium chromate, reinforcing the link between oxides and severe corrosion. In addition to the pitting corrosion, a large blister formed on the side wall, which was mainly composed of potassium, chromium and oxygen. All data indicated that corrosion initiated internally and moved outward. There was no evidence of intergranular corrosion nor were there any indication of fast pathways along grain boundaries. Much of the pitting occurred near welds; however this was the hottest region in the chamber. Pitting was observed up to two inches above the weld, indicating independence from weld effects.« less

Shock initiation of explosives: High temperature hot spots explained

NASA Astrophysics Data System (ADS)

Bassett, Will P.; Johnson, Belinda P.; Neelakantan, Nitin K.; Suslick, Kenneth S.; Dlott, Dana D.

2017-08-01

We investigated the shock initiation of energetic materials with a tabletop apparatus that uses km s-1 laser-driven flyer plates to initiate tiny explosive charges and obtains complete temperature histories with a high dynamic range. By comparing various microstructured formulations, including a pentaerythritol tetranitrate (PETN) based plastic explosive (PBX) denoted XTX-8003, we determined that micron-scale pores were needed to create high hot spot temperatures. In charges where micropores (i.e., micron-sized pores) were present, a hot spot temperature of 6000 K was observed; when the micropores were pre-compressed to nm scale, however, the hot spot temperature dropped to ˜4000 K. By comparing XTX-8003 with an analog that replaced PETN by nonvolatile silica, we showed that the high temperatures require gas in the pores, that the high temperatures were created by adiabatic gas compression, and that the temperatures observed can be controlled by the choice of ambient gases. The hot spots persist in shock-compressed PBXs even in vacuum because the initially empty pores became filled with gas created in-situ by shock-induced chemical decomposition.

An Observationally-Centred Method to Quantify the Changing Shape of Local Temperature Distributions

NASA Astrophysics Data System (ADS)

Chapman, S. C.; Stainforth, D. A.; Watkins, N. W.

2014-12-01

For climate sensitive decisions and adaptation planning, guidance on how local climate is changing is needed at the specific thresholds relevant to particular impacts or policy endeavours. This requires the quantification of how the distributions of variables, such as daily temperature, are changing at specific quantiles. These temperature distributions are non-normal and vary both geographically and in time. We present a method[1,2] for analysing local climatic time series data to assess which quantiles of the local climatic distribution show the greatest and most robust changes. We have demonstrated this approach using the E-OBS gridded dataset[3] which consists of time series of local daily temperature across Europe over the last 60 years. Our method extracts the changing cumulative distribution function over time and uses a simple mathematical deconstruction of how the difference between two observations from two different time periods can be assigned to the combination of natural statistical variability and/or the consequences of secular climate change. The change in temperature can be tracked at a temperature threshold, at a likelihood, or at a given return time, independently for each geographical location. Geographical correlations are thus an output of our method and reflect both climatic properties (local and synoptic), and spatial correlations inherent in the observation methodology. We find as an output many regionally consistent patterns of response of potential value in adaptation planning. For instance, in a band from Northern France to Denmark the hottest days in the summer temperature distribution have seen changes of at least 2°C over a 43 year period; over four times the global mean change over the same period. We discuss methods to quantify the robustness of these observed sensitivities and their statistical likelihood. This approach also quantifies the level of detail at which one might wish to see agreement between climate models and observations if such models are to be used directly as tools to assess climate change impacts at local scales. [1] S C Chapman, D A Stainforth, N W Watkins, 2013, Phil. Trans. R. Soc. A, 371 20120287. [2] D A Stainforth, S C Chapman, N W Watkins, 2013, Environ. Res. Lett. 8, 034031 [3] Haylock, M.R. et al., 2008, J. Geophys. Res (Atmospheres), 113, D20119

Worlds Fantastic, Worlds Familiar

NASA Astrophysics Data System (ADS)

Buratti, Bonnie J.

2017-02-01

Introduction; 1. Mercury: the hottest little place; 2. Venus: an even hotter place; 3. Mars: the abode of life?; 4. Asteroids and comets: sweat the small stuff; 5. Galileo's treasures: worlds of fire and ice; 6. Enceladus: an active iceball in space; 7. Titan: an Earth in deep freeze?; 8. Iapetus and its friends: the weirdest 'planets' in the Solar System; 9. Pluto: the first view of the 'third zone'; 10. Earths above: the search for exoplanets and life in the universe; Epilogue; Glossary; Acknowledgements; Index.

Alcorn wells bolster Philippines oil production

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

Not Available

1992-09-21

This paper reports that Alcorn International Inc., Houston, is producing about 16,500 b/d of oil from West Linapacan A field in the South China Sea off the Philippines. The field's current production alone is more than fivefold the Philippines' total average oil flow of 3,000 b/d in 1991. It's part of a string of oil and gas strikes off Palawan Island that has made the region one of the hottest exploration/development plays in the Asia-Pacific theater.

Structural changes and damage of single-crystal turbine blades during life tests of an aviation gas turbine engine

NASA Astrophysics Data System (ADS)

Ospennikova, O. G.; Orlov, M. R.; Kolodochkina, V. G.; Nazarkin, R. M.

2015-04-01

The irreversible structural changes of the single-crystal ZhS32-VI nickel superalloy blades of a high-pressure turbine that occur during life tests of a gas turbine engine are studied. The main operation damages in the hottest section of the blade airfoil are found to be the fracture of the heat-resistant coating in the leading edge and the formation of thermomechanical fatigue cracks. The possibility of reconditioning repair of the blades is considered.

Environmental Control Unit with Integral Thermal Storage

DTIC Science & Technology

2014-06-12

integrated PCM Heat Exchanger (PHX) to provide thermal energy storage . By storing thermal energy during the hottest part of the day and rejecting this stored...Environmental Control Unit (ECU) that uses an integrated PCM Heat Exchanger (PHX) to provide thermal energy storage . To aid in the development of the PHX...Thermal Storage 5a. CONTRACT NUMBER W911QX-14-C-0014 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Michael C. Ellis Ryan McDevitt 5d

Deposing the Cool Corona of KPD 0005+5106

NASA Astrophysics Data System (ADS)

Werner, K.; Drake, J. J.

2005-07-01

We show that the Chandra LETG spectrum of the hottest known DO white dwarf, KPD 0005+5106, can be qualitatively modelled as photospheric emission, and does not require a coronal explanation. The excess flux found by Fleming et al. (1993) in the 0.2-0.3 keV region arises from deeper atmospheric layers revealed by a lower continuous opacity in this region. The 1 keV emission found by O'Dwyer et al. (2003) lies below our detection threshold, but cannot be explained by photospheric models.

Nustar: Bringing the High-Energy Universe into Focus

NASA Technical Reports Server (NTRS)

Fineberg, Larry

2016-01-01

This is a presentation to students at the University of Florida in the Small Satellite Design Club. The subject matter is the NuSTAR mission and covers topics about the spacecraft itself and the launch campaign. NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) is the first focusing high-energy X-ray mission. Studies the hottest, densest, most energetic phenomena in the Universe. Purpose is to search for black holes, map the remnants of stellar explosions, and study the most extreme active galaxies.

Diabetes in the Desert: What Do Patients Know about the Heat?

PubMed Central

Nassar, Adrienne A; Childs, Raymond D; Boyle, Mary E; Jameson, Kimberly A; Fowke, Margaret; Waters, Ken R; Hovan, Michael J; Cook, Curtiss B

2010-01-01

Background This study aims to identify self-management strategies used by patients with diabetes in hot weather, examine knowledge of safe temperatures and exposure times, and evaluate comprehension of weather data. Methods Patients attending an endocrinology clinic in southwestern United States were surveyed. Results One hundred fifty-two surveys completed from November 30 to December 31, 2009 werMean patient age was 64 years; diabetes duration e analyzed 15 years; 51% were women 83% had type 2 diabetes, 58% were non Hispanic white, and 77% were on insulin injections. Mean hemoglobin A1c was 7.9%; 38% had hemoglobin A1c values of 8.0% or higher. Patients used an array of personal protective measures during hot weather, and 71% limited heat exposure to less than one hour. Respondents typically took steps to protect their diabetes medication and supplies, but 37% chose to leave medications and supplies at home. Although 73% of respondents had received information regarding the effect of heat on insulin, only 39% had received information about the effect of heat on oral medications, 41% on glucose meters, and 38% on glucose test strips. The temperature at which patients took protective measures varied. Only 55% knew the definition of the heat index. Conclusion Most survey participants took measures to protect themselves from the heat, although gaps in knowledge were evident. Many patients had suboptimal glycemic control, placing them potentially at risk for dehydration during the hottest months. Increased public awareness of this topic is needed, and diabetes education programs should include information about the heat where appropriate. PMID:20920435

A Strong Shallow Heat Source in the Accreting Neutron Star MAXI J0556-332

NASA Astrophysics Data System (ADS)

Deibel, Alex; Cumming, Andrew; Brown, Edward F.; Page, Dany

2015-08-01

An accretion outburst in an X-ray transient deposits material onto the neutron star primary; this accumulation of matter induces reactions in the neutron star’s crust. During the accretion outburst these reactions heat the crust out of thermal equilibrium with the core. When accretion halts, the crust cools to its long-term equilibrium temperature on observable timescales. Here we examine the accreting neutron star transient MAXI J0556-332, which is the hottest transient, at the start of quiescence, observed to date. Models of the quiescent light curve require a large deposition of heat in the shallow outer crust from an unknown source. The additional heat injected is ≈4-10 MeV per accreted nucleon; when the observed decline in accretion rate at the end of the outburst is accounted for, the required heating increases to ≈6-16 MeV. This shallow heating is still required to fit the light curve even after taking into account a second accretion episode, uncertainties in distance, and different surface gravities. The amount of shallow heating is larger than that inferred for other neutron star transients and is larger than can be supplied by nuclear reactions or compositionally driven convection; but it is consistent with stored mechanical energy in the accretion disk. The high crust temperature ({T}b≳ {10}9 {{K}}) makes its cooling behavior in quiescence largely independent of the crust composition and envelope properties, so that future observations will probe the gravity of the source. Fits to the light curve disfavor the presence of Urca cooling pairs in the crust.

Optimizing Performance of a Thermal Energy Storage System

NASA Astrophysics Data System (ADS)

Subirats Soler, Monica

In this thesis, the problem of electricity demand shifting for the cooling needs of a large institution using a thermal energy storage (TES) tank is considered. The system is formed by electric chillers, cooling towers and a TES tank that can store energy for the cooling demand of most days, but not for the hottest ones. The goal is to supply all the cooling needed while minimizing the cost. This is done by shifting the cooling demand to night and early morning hours, when electricity is cheaper and due to lower temperatures, the chillers work more efficiently. This is all done with the help of the TES tank, that acts as a buffer storing chilled water. After a series of assumptions and simplifications, the cost function becomes convex and thus a minimum solution exists. However, from previous work only the chillers were considered, omitting the negative effect that other components of the system, such as cooling towers, had on the overall cost of operation. Using data from the operation of the power plant under real conditions, a method to model the whole system is presented in this thesis. In addition, the algorithm relied on the knowledge of an accurate prediction of the cooling demand, which obviously is not known in advance. A method to predict it starting from a forecasting of the temperature is presented. Finally, the algorithm can be easily modified to allow the imposition constraints that limit the maximum power use of chillers, during specific periods, in response to the overall needs of the micro-grid.

Chemical and Kinematical Properties of Blue Straggler Stars and Horizontal Branch Stars in NGC 6397

NASA Astrophysics Data System (ADS)

Lovisi, L.; Mucciarelli, A.; Lanzoni, B.; Ferraro, F. R.; Gratton, R.; Dalessandro, E.; Contreras Ramos, R.

2012-08-01

We used three sets of high-resolution spectra acquired with the multifiber facility FLAMES at the Very Large Telescope of the European Southern Observatory to investigate the chemical and kinematical properties of a sample of 42 horizontal branch (HB) stars, 18 blue straggler stars (BSSs), and 86 main-sequence (MS) turnoff (TO) and sub-giant branch stars in the nearby globular cluster NGC 6397. We measured rotational velocities and Fe, O, and Mg abundances. All of the unevolved stars in our sample have low rotational velocites (vsin i < 10 km s-1), while the HB stars and BSSs show a broad distribution, with values ranging from 0 to ~70 km s-1. For HB stars with T < 10,500 K there is a clear temperature-oxygen anticorrelation that can be understood if the star position along the HB is mainly determined by the He content. The hottest BSSs and HB stars (with temperatures T > 8200 K and T > 10,500 K, respectively) also show significant deviations in their iron abundance with respect to the cluster metallicity (as traced by the unevolved stars, [Fe/H] = -2.12). While similar chemical patterns have already been observed in other hot HB stars, this is the first evidence ever collected for BSSs. We interpret these abundance anomalies as due to the metal radiative levitation, occurring in stars with shallow or no convective envelopes. Based on FLAMES observations collected at the European Southern Observatory, proposal numbers 073.D-0058, 075.D-0125, and 081.D-0356.

Bird population trends are linearly affected by climate change along species thermal ranges.

PubMed

Jiguet, Frédéric; Devictor, Vincent; Ottvall, Richard; Van Turnhout, Chris; Van der Jeugd, Henk; Lindström, Ake

2010-12-07

Beyond the effects of temperature increase on local population trends and on species distribution shifts, how populations of a given species are affected by climate change along a species range is still unclear. We tested whether and how species responses to climate change are related to the populations locations within the species thermal range. We compared the average 20 year growth rates of 62 terrestrial breeding birds in three European countries along the latitudinal gradient of the species ranges. After controlling for factors already reported to affect bird population trends (habitat specialization, migration distance and body mass), we found that populations breeding close to the species thermal maximum have lower growth rates than those in other parts of the thermal range, while those breeding close to the species thermal minimum have higher growth rates. These results were maintained even after having controlled for the effect of latitude per se. Therefore, the results cannot solely be explained by latitudinal clines linked to the geographical structure in local spring warming. Indeed, we found that populations are not just responding to changes in temperature at the hottest and coolest parts of the species range, but that they show a linear graded response across their European thermal range. We thus provide insights into how populations respond to climate changes. We suggest that projections of future species distributions, and also management options and conservation assessments, cannot be based on the assumption of a uniform response to climate change across a species range or at range edges only.

Imprints of the ejecta-companion interaction in Type Ia supernovae: main-sequence, subgiant, and red giant companions

NASA Astrophysics Data System (ADS)

Boehner, P.; Plewa, T.; Langer, N.

2017-02-01

We study supernova ejecta-companion interactions in a sample of realistic semidetached binary systems representative of Type Ia supernova progenitor binaries in a single-degenerate scenario. We model the interaction process with the help of a high-resolution hydrodynamic code assuming cylindrical symmetry. We find that the ejecta hole has a half-opening angle of 40-50° with the density by a factor of 2-4 lower, in good agreement with the previous studies. Quantitative differences from the past results in the amounts and kinematics of the stripped companion material and levels of contamination of the companion with the ejecta material can be explained by different model assumptions and effects due to numerical diffusion. We analyse and, for the first time, provide simulation-based estimates of the amounts and of the thermal characteristics of the shock-heated material responsible for producing a prompt, soft X-ray emission. Besides the shocked ejecta material, considered in the original model by Kasen, we also account for the stripped, shock-heated envelope material of stellar companions, which we predict partially contributes to the prompt emission. The amount of the energy deposited in the envelope is comparable to the energy stored in the ejecta. The total energy budget available for the prompt emission is by a factor of about 2-4 smaller than originally predicted by Kasen. Although the shocked envelope has a higher characteristic temperature than the shocked ejecta, the temperature estimates of the shocked material are in good agreement with the Kasen's model. The hottest shocked plasma is produced in the subgiant companion case.

Diversity of thermophiles in a Malaysian hot spring determined using 16S rRNA and shotgun metagenome sequencing

PubMed Central

Chan, Chia Sing; Chan, Kok-Gan; Tay, Yea-Ling; Chua, Yi-Heng; Goh, Kian Mau

2015-01-01

The Sungai Klah (SK) hot spring is the second hottest geothermal spring in Malaysia. This hot spring is a shallow, 150-m-long, fast-flowing stream, with temperatures varying from 50 to 110°C and a pH range of 7.0–9.0. Hidden within a wooded area, the SK hot spring is continually fed by plant litter, resulting in a relatively high degree of total organic content (TOC). In this study, a sample taken from the middle of the stream was analyzed at the 16S rRNA V3-V4 region by amplicon metagenome sequencing. Over 35 phyla were detected by analyzing the 16S rRNA data. Firmicutes and Proteobacteria represented approximately 57% of the microbiome. Approximately 70% of the detected thermophiles were strict anaerobes; however, Hydrogenobacter spp., obligate chemolithotrophic thermophiles, represented one of the major taxa. Several thermophilic photosynthetic microorganisms and acidothermophiles were also detected. Most of the phyla identified by 16S rRNA were also found using the shotgun metagenome approaches. The carbon, sulfur, and nitrogen metabolism within the SK hot spring community were evaluated by shotgun metagenome sequencing, and the data revealed diversity in terms of metabolic activity and dynamics. This hot spring has a rich diversified phylogenetic community partly due to its natural environment (plant litter, high TOC, and a shallow stream) and geochemical parameters (broad temperature and pH range). It is speculated that symbiotic relationships occur between the members of the community. PMID:25798135

Climate Change Impacts on Peak Electricity Consumption: US vs. Europe.

NASA Astrophysics Data System (ADS)

Auffhammer, M.

2016-12-01

It has been suggested that climate change impacts on the electric sector will account for the majority of global economic damages by the end of the current century and beyond. This finding is at odds with the relatively modest increase in climate driven impacts on consumption. Comprehensive high frequency load balancing authority level data have not been used previously to parameterize the relationship between electric demand and temperature for any major economy. Using statistical models we analyze multi-year data from load balancing authorities in the United States of America and the European Union, which are responsible for more than 90% of the electricity delivered to residential, industrial, commercial and agricultural customers. We couple the estimated response functions between total daily consumption and daily peak load with an ensemble of downscaled GCMs from the CMIP5 archive to simulate climate change driven impacts on both outcomes. We show moderate and highly spatially heterogeneous changes in consumption. The results of our peak load simulations, however, suggest significant changes in the intensity and frequency of peak events throughout the United States and Europe. As the electricity grid is built to endure maximum load, which usually occurs on the hottest day of the year, our findings have significant implications for the construction of costly peak generating and transmission capacity.

Seasonal variation and natural infection of Lutzomyia antunesi (Diptera: Psychodidae: Phlebotominae), an endemic species in the Orinoquia region of Colombia.

PubMed

Vásquez Trujillo, Adolfo; González Reina, Angélica E; Góngora Orjuela, Agustín; Prieto Suárez, Edgar; Palomares, Jairo Enrique; Buitrago Alvarez, Luz Stella

2013-06-01

Lutzomyia antunesi has been commonly reported in outbreaks of cutaneous leishmaniasis (CL) in the Orinoquia region of Colombia. The bionomics of this species were studied in the municipality of Villavicencio (Meta, Colombia). Sandflies were captured over the course of one week per month for one year in intradomiciliary, peridomiciliary and extradomiciliary housing areas. The captures were performed from 06:00 pm-06:00 am using CDC light traps and the females were processed for polymerase chain reaction (PCR) to detect Leishmania spp. A total of 22,097 specimens and 19 species were captured of which Lu. antunesi (89%) and Lutzomyia walkeri (5%) were the most abundant. Other species recognised as anthropophilic (Lutzomyia panamensis, Lutzomyia gomezi, Lutzomyia flaviscutellata and Lutzomyia fairtigi) were present in very low abundance (< 2%). Natural infection with Leishmania spp was detected using PCR in Lu. antunesi, Lu. panamensis and Lu. flavicutellata, showing infection rates of 1%, 4.8% and 7.5%, respectively. The present paper provides information on various ecological aspects of Lu. antunesi. An analysis of seasonality shows that this species increases in abundance in the hottest months (December, January and February), directly correlating with the maximum temperature and inversely correlating with precipitation. The natural infection rate is associated with the peaks of highest abundance.

KELT-17b: A Hot-Jupiter Transiting an A-star in a Misaligned Orbit Detected with Doppler Tomography

NASA Astrophysics Data System (ADS)

Zhou, George; Rodriguez, Joseph E.; Collins, Karen A.; Beatty, Thomas; Oberst, Thomas; Heintz, Tyler M.; Stassun, Keivan G.; Latham, David W.; Kuhn, Rudolf B.; Bieryla, Allyson; Lund, Michael B.; Labadie-Bartz, Jonathan; Siverd, Robert J.; Stevens, Daniel J.; Gaudi, B. Scott; Pepper, Joshua; Buchhave, Lars A.; Eastman, Jason; Colón, Knicole; Cargile, Phillip; James, David; Gregorio, Joao; Reed, Phillip A.; Jensen, Eric L. N.; Cohen, David H.; McLeod, Kim K.; Tan, T. G.; Zambelli, Roberto; Bayliss, Daniel; Bento, Joao; Esquerdo, Gilbert A.; Berlind, Perry; Calkins, Michael L.; Blancato, Kirsten; Manner, Mark; Samulski, Camile; Stockdale, Christopher; Nelson, Peter; Stephens, Denise; Curtis, Ivan; Kielkopf, John; Fulton, Benjamin J.; DePoy, D. L.; Marshall, Jennifer L.; Pogge, Richard; Gould, Andy; Trueblood, Mark; Trueblood, Pat

2016-11-01

We present the discovery of a hot Jupiter transiting the V = 9.23 mag main-sequence A-star KELT-17 (BD+14 1881). KELT-17b is a {1.31}-0.29+0.28 {M}{{J}}, {1.525}-0.060+0.065 {R}{{J}} hot-Jupiter in a 3.08-day period orbit misaligned at -115.°9 ± 4.°1 to the rotation axis of the star. The planet is confirmed via both the detection of the radial velocity orbit, and the Doppler tomographic detection of the shadow of the planet during two transits. The nature of the spin-orbit misaligned transit geometry allows us to place a constraint on the level of differential rotation in the host star; we find that KELT-17 is consistent with both rigid-body rotation and solar differential rotation rates (α \\lt 0.30 at 2σ significance). KELT-17 is only the fourth A-star with a confirmed transiting planet, and with a mass of {1.635}-0.061+0.066 {M}⊙ , an effective temperature of 7454 ± 49 K, and a projected rotational velocity of v\\sin {I}* ={44.2}-1.3+1.5 {km} {{{s}}}-1; it is among the most massive, hottest, and most rapidly rotating of known planet hosts.

A Hot White Dwarf SDSS J134430.11+032423.1 with a Planetary Debris Disk

NASA Astrophysics Data System (ADS)

Li, Lifang; Zhang, Fenghui; Kong, Xiaoyang; Han, Quanwang; Li, Jiansha

2017-02-01

We discovered a debris disk around hot white dwarf (WD) SDSS J134430.11+032423.1 (SDSS J1344+0324). The effective temperature [{T}{eff} = 26,071(±163) K], surface gravity [{log}g=7.88(2)], and mass [M=0.58(1) {M}⊙ ] of this WD have been redetermined based on the analysis of its SDSS spectrum. We found that SDSS J1344+0324 is currently the hottest WD with a debris disk. Two spectra observed by SDSS at different times show that this object is similar to SDSS J1228+1040 with variable near-IR Ca II triplet emissions from a gaseous disk. The parameters of the debris disk are derived from the IR excess analysis of SDSS J1344+0324. We found that the disk is the coolest of all debris disks around WDs, and that the inner and outer radii are very close to the tide radius of the WD. Thus, the debris disk is very narrow (about 0.22 {R}⊙ ). This implies that it might be a newly formed disk resulting from the tidal disruption of a rocky planetary body that has just entered the tide volume of the WD. This might provide strong observational evidence for the formation of debris disks around WDs.

Importance of determining the climatic domains of sheep breeds.

PubMed

Petit, D; Boujenane, I

2018-07-01

The main purpose of the study was to compare the capacity of the major sheep breeds in Morocco to cope with climate changes through the ranges of several climate parameters in which they can be found. We first delimitated the climatic 'domains' of each breed by constructing a database including altitude and climatic parameters (minima mean of the coldest month, maxima mean of the hottest month, annual rainfall, pluviothermic coefficient of Emberger Q 2, annual minima mean and annual maxima mean) on a 30-year period using the representative stations of each breed distribution. The overlap between each breed combination was quantified through a canonical analysis that extracted the most discriminant parameters. The variance analysis of each climatic parameter evidenced two breeds remarkable by their tolerance. The first one is the Timahdite, mainly settled in areas over 1100 m, which can tolerate the greatest variations in annual rainfall and pluviothermic coefficient. In spite of this feature, this breed is endangered owing to the decreasing quality of pastures. The second one is the D'man which apparently can support high variations in extreme temperatures. In fact, this breed is not well adapted to pastures and requires a special microclimate offered by oases. The information reported in this study will be the basis for the establishment of characterization and selection strategies for Moroccan sheep.

Seasonal variation and natural infection of Lutzomyia antunesi (Diptera: Psychodidae: Phlebotominae), an endemic species in the Orinoquia region of Colombia

PubMed Central

Trujillo, Adolfo Vásquez; Reina, Angélica E González; Orjuela, Agustín Góngora; Suárez, Edgar Prieto; Palomares, Jairo Enrique; Alvarez, Luz Stella Buitrago

2013-01-01

Lutzomyia antunesi has been commonly reported in outbreaks of cutaneous leishmaniasis (CL) in the Orinoquia region of Colombia. The bionomics of this species were studied in the municipality of Villavicencio (Meta, Colombia). Sandflies were captured over the course of one week per month for one year in intradomiciliary, peridomiciliary and extradomiciliary housing areas. The captures were performed from 06:00 pm-06:00 am using CDC light traps and the females were processed for polymerase chain reaction (PCR) to detect Leishmania spp. A total of 22,097 specimens and 19 species were captured of which Lu. antunesi (89%) and Lutzomyia walkeri (5%) were the most abundant. Other species recognised as anthropophilic (Lutzomyia panamensis, Lutzomyia gomezi, Lutzomyia flaviscutellata and Lutzomyia fairtigi) were present in very low abundance (< 2%). Natural infection with Leishmania spp was detected using PCR in Lu. antunesi, Lu. panamensis and Lu. flavicutellata, showing infection rates of 1%, 4.8% and 7.5%, respectively. The present paper provides information on various ecological aspects of Lu. antunesi. An analysis of seasonality shows that this species increases in abundance in the hottest months (December, January and February), directly correlating with the maximum temperature and inversely correlating with precipitation. The natural infection rate is associated with the peaks of highest abundance. PMID:23828011

Historical deforestation locally increased the intensity of hot days in northern mid-latitudes

NASA Astrophysics Data System (ADS)

Lejeune, Quentin; Davin, Edouard L.; Gudmundsson, Lukas; Winckler, Johannes; Seneviratne, Sonia I.

2018-05-01

The effects of past land-cover changes on climate are disputed1-3. Previous modelling studies have generally concluded that the biogeophysical effects of historical deforestation led to an annual mean cooling in the northern mid-latitudes3,4, in line with the albedo-induced negative radiative forcing from land-cover changes since pre-industrial time reported in the most recent Intergovernmental Panel on Climate Change report5. However, further observational and modelling studies have highlighted strong seasonal and diurnal contrasts in the temperature response to deforestation6-10. Here, we show that historical deforestation has led to a substantial local warming of hot days over the northern mid-latitudes—a finding that contrasts with most previous model results11,12. Based on observation-constrained state-of-the-art climate-model experiments, we estimate that moderate reductions in tree cover in these regions have contributed at least one-third of the local present-day warming of the hottest day of the year since pre-industrial time, and were responsible for most of this warming before 1980. These results emphasize that land-cover changes need to be considered when studying past and future changes in heat extremes, and highlight a potentially overlooked co-benefit of forest-based carbon mitigation through local biogeophysical mechanisms.

Properties of filamentary sublimation residues from dispersions of clay in ice. [on Martian poles, comet nuclei, and icy satellites

NASA Technical Reports Server (NTRS)

Saunders, R. S.; Parker, T. J.; Stephens, J. B.; Fanale, F. P.; Sutton, S.

1986-01-01

Results are reported from experimental studies of the formation of ice mixed with mineral particles in an effort to simulate similar processes on natural surfaces such as at the Martian poles, on comet nuclei and on icy satellites. The study consisted of low-pressure, low-temperature sublimations of water ice from dilutions of water-clay (montmorillonite and Cabosil) dispersions of various component ratios. Liquid dispersions were sprayed into liquid nitrogen to form droplets at about -50 C. Both clay-water dispersions left a filamentary residue on the bottom of the Dewar after the water ice had sublimated off. The residue was studied with optical and SEM microscopy, the latter method revealing a high electrical conductivity in the residue. The results suggest that the sublimation of the water ice can leave a surface crust, which may be analogous to processes at the Martian poles and on comet nuclei. The process could proceed by the attachment of water molecules to salt crystals during the hottest part of the Martian year. The residue remaining was found to remain stable up to 370 C, be porous, and remain resilient, which could allow it to insulate ice bodies such as comets in space.

Liquidus temperatures of komatiites and the effect of cooling rate on element partitioning between olivine and komatiitic melt

NASA Astrophysics Data System (ADS)

Sossi, Paolo A.; O'Neill, Hugh St. C.

2016-05-01

Archean komatiites are the hottest magmas preserved on Earth and are thus unique probes of its thermal evolution. Estimating their eruption temperatures remains problematic, however, because the uppermost (A1, A2) zones of komatiite flows contain randomly oriented spinifex-textured olivines, indicative of rapid cooling and growth. Fe-Mg partitioning between olivine and assumed komatiitic liquid typically shows departures from equilibrium, extending towards higher K_{{D}}^{{{{Fe}}^{2 + } - {{Mg}}}}. If these higher values are a disequilibrium effect, using them to calculate parental magma composition would lead to errors in estimated liquidus temperatures. In order to investigate this possibility, we have performed experiments on two komatiite compositions, the classic Barberton Aluminium Undepleted Komatiite (AUK) sample 49J (32.2 % MgO) and Munro AUK sample 422/95 (23 % MgO). Isothermal experiments to constrain phase equilibria on 49J at atmospheric pressure, between 1360 and 1600 °C at 1.7 log units below and 1.1 above the fayalite-magnetite-quartz (FMQ) buffer reveal a liquidus temperature ( T liq) of 1616 °C, 40 °C lower than a previous estimate. The K_{{D}}^{{Σ {{Fe}}{-}{{Mg}}}} ranges between 0.320 and 0.295 at FMQ - 1.7, with a slight negative dependence on temperature. To replicate the conditions that prevailed during the quenching of komatiites in their upper chill zones, experiments with a constant cooling rate at FMQ - 1.7 were performed on 422/95 ( T liq = 1450 °C) at 0.5, 1.5, 2.5, 6.5 and 16 °C/min. Olivine morphology changes from euhedral to tabular at low cooling rates, hopper at intermediate, and skeletal and chain structures at high rates. Concurrently, the K_{{D}}^{{Σ {{Fe}}{-}{{Mg}}}} increases monotonically from an equilibrium value of 0.305 to 0.376 at 16 °C/min, reflecting the inability of unwanted cations to diffuse away from the growing olivine. The high K_{{D}}^{{Σ {{Fe}}{-}{{Mg}}}} between olivine and komatiitic liquid caused by rapid cooling accounts for the systematically lower Mg#s in spinifex olivines with respect to their euhedral counterparts in natural komatiites. The maximum MgO content of komatiite liquids in the Archean is revised upwards to 32 wt%, implying temperature excesses in Archean plumes relative to ambient mantle were greater than in their contemporary equivalents.

Microclimate variables of the ambient environment deliver the actual estimates of the extrinsic incubation period of Plasmodium vivax and Plasmodium falciparum: a study from a malaria-endemic urban setting, Chennai in India.

PubMed

Thomas, Shalu; Ravishankaran, Sangamithra; Justin, N A Johnson Amala; Asokan, Aswin; Kalsingh, T Maria Jusler; Mathai, Manu Thomas; Valecha, Neena; Montgomery, Jacqui; Thomas, Matthew B; Eapen, Alex

2018-05-16

Environmental factors such as temperature, relative humidity and their daily variation influence a range of mosquito life history traits and hence, malaria transmission. The standard way of characterizing environmental factors with meteorological station data need not be the actual microclimates experienced by mosquitoes within local transmission settings. A year-long study was conducted in Chennai, India to characterize local temperature and relative humidity (RH). Data loggers (Hobos) were placed in a range of probable indoor and outdoor resting sites of Anopheles stephensi. Recordings were taken hourly to estimate mean temperature and RH, together with daily temperature range (DTR) and daily relative humidity range. The temperature data were used to explore the predicted variation in extrinsic incubation period (EIP) of Plasmodium falciparum and Plasmodium vivax between microhabitats and across the year. Mean daily temperatures within the indoor settings were significantly warmer than those recorded outdoors. DTR in indoor environments was observed to be modest and ranged from 2 to 6 °C. Differences in EIP between microhabitats were most notable during the hottest summer months of April-June, with parasite development predicted to be impaired for tiled houses and overhead tanks. Overall, the prevailing warm and stable conditions suggest rapid parasite development rate regardless of where mosquitoes might rest. Taking account of seasonal and local environmental variation, the predicted EIP of P. falciparum varied from a minimum of 9.1 days to a maximum of 15.3 days, while the EIP of P. vivax varied from 8.0 to 24.3 days. This study provides a detailed picture of the actual microclimates experienced by mosquitoes in an urban slum malaria setting. The data indicate differences between microhabitats that could impact mosquito and parasite life history traits. The predicted effects for EIP are often relatively subtle, but variation between minimum and maximum EIPs can play a role in disease transmission, depending on the time of year and where mosquitoes rest. Appropriate characterization of the local microclimate conditions would be the key to fully understand the effects of environment on local transmission ecology.

The diversity of floral temperature patterns, and their use by pollinators

PubMed Central

Harrap, Michael JM; Hempel de Ibarra, Natalie; Whitney, Heather M

2017-01-01

Pollinating insects utilise various sensory cues to identify and learn rewarding flower species. One such cue is floral temperature, created by captured sunlight or plant thermogenesis. Bumblebees, honeybees and stingless bees can distinguish flowers based on differences in overall temperature between flowers. We report here that floral temperature often differs between different parts of the flower creating a temperature structure or pattern. Temperature patterns are common, with 55% of 118 plant species thermographed, showing within-flower temperature differences greater than the 2°C difference that bees are known to be able to detect. Using differential conditioning techniques, we show that bumblebees can distinguish artificial flowers differing in temperature patterns comparable to those seen in real flowers. Thus, bumblebees are able to perceive the shape of these within-flower temperature patterns. Floral temperature patterns may therefore represent a new floral cue that could assist pollinators in the recognition and learning of rewarding flowers. PMID:29254518

Grape Ripening Is Regulated by Deficit Irrigation/Elevated Temperatures According to Cluster Position in the Canopy

PubMed Central

Zarrouk, Olfa; Brunetti, Cecilia; Egipto, Ricardo; Pinheiro, Carla; Genebra, Tânia; Gori, Antonella; Lopes, Carlos M.; Tattini, Massimiliano; Chaves, M. Manuela

2016-01-01

The impact of water deficit on berry quality has been extensively investigated during the last decades. Nonetheless, there is a scarcity of knowledge on the performance of varieties exposed to a combination of high temperatures/water stress during the growing season and under vineyard conditions. The objective of this research was to investigate the effects of two irrigation regimes, sustained deficit irrigation (SDI, 30% ETc) and regulated deficit irrigation (RDI, 15% ETc) and of two cluster positions within the canopy (east- and west-exposed sides) on berry ripening in red Aragonez (Tempranillo) grapevines. The study was undertaken for two successive years in a commercial vineyard in South Portugal, monitoring the following parameters: pre-dawn leaf water potential, berry temperature, sugars, polyphenols, abscisic acid (ABA) and related metabolites. Additionally, expression patterns for different transcripts encoding for enzymes responsible for anthocyanin and ABA biosynthesis (VviUFGT, VvNCED1, VvβG1, VviHyd1, VviHyd2) were analyzed. In both years anthocyanin concentration was lower in RDI at the west side (RDIW- the hottest one) from véraison onwards, suggesting that the most severe water stress conditions exacerbated the negative impact of high temperature on anthocyanin. The down-regulation of VviUFGT expression revealed a repression of the anthocyanin synthesis in berries of RDIW, at early stages of berry ripening. At full-maturation, anthocyanin degradation products were detected, being highest at RDIW. This suggests that the negative impact of water stress and high temperature on anthocyanins results from the repression of biosynthesis at the onset of ripening and from degradation at later stages. On the other hand, berries grown under SDI displayed a higher content in phenolics than those under RDI, pointing out for the attenuation of the negative temperature effects under SDI. Irrigation regime and berry position had small effect on free-ABA concentration. However, ABA catabolism/conjugation process and ABA biosynthetic pathway were affected by water and heat stresses. This indicates the role of ABA-GE and catabolites in berry ABA homeostasis under abiotic stresses. Principal component analysis (PCA) showed that the strongest influence in berry ripening is the deficit irrigation regime, while temperature is an important variable determining the improvement or impairment of berry quality by the deficit irrigation regime. In summary, this work shows the interaction between irrigation regime and high temperature on the control of berry ripening. PMID:27895648

Grape Ripening Is Regulated by Deficit Irrigation/Elevated Temperatures According to Cluster Position in the Canopy.

PubMed

Zarrouk, Olfa; Brunetti, Cecilia; Egipto, Ricardo; Pinheiro, Carla; Genebra, Tânia; Gori, Antonella; Lopes, Carlos M; Tattini, Massimiliano; Chaves, M Manuela

2016-01-01

The impact of water deficit on berry quality has been extensively investigated during the last decades. Nonetheless, there is a scarcity of knowledge on the performance of varieties exposed to a combination of high temperatures/water stress during the growing season and under vineyard conditions. The objective of this research was to investigate the effects of two irrigation regimes, sustained deficit irrigation (SDI, 30% ET c ) and regulated deficit irrigation (RDI, 15% ET c ) and of two cluster positions within the canopy (east- and west-exposed sides) on berry ripening in red Aragonez (Tempranillo) grapevines. The study was undertaken for two successive years in a commercial vineyard in South Portugal, monitoring the following parameters: pre-dawn leaf water potential, berry temperature, sugars, polyphenols, abscisic acid (ABA) and related metabolites. Additionally, expression patterns for different transcripts encoding for enzymes responsible for anthocyanin and ABA biosynthesis ( VviUFGT, VvNCED1, Vv β G1, VviHyd1, VviHyd2 ) were analyzed. In both years anthocyanin concentration was lower in RDI at the west side (RDIW- the hottest one) from véraison onwards, suggesting that the most severe water stress conditions exacerbated the negative impact of high temperature on anthocyanin. The down-regulation of VviUFGT expression revealed a repression of the anthocyanin synthesis in berries of RDIW, at early stages of berry ripening. At full-maturation, anthocyanin degradation products were detected, being highest at RDIW. This suggests that the negative impact of water stress and high temperature on anthocyanins results from the repression of biosynthesis at the onset of ripening and from degradation at later stages. On the other hand, berries grown under SDI displayed a higher content in phenolics than those under RDI, pointing out for the attenuation of the negative temperature effects under SDI. Irrigation regime and berry position had small effect on free-ABA concentration. However, ABA catabolism/conjugation process and ABA biosynthetic pathway were affected by water and heat stresses. This indicates the role of ABA-GE and catabolites in berry ABA homeostasis under abiotic stresses. Principal component analysis (PCA) showed that the strongest influence in berry ripening is the deficit irrigation regime, while temperature is an important variable determining the improvement or impairment of berry quality by the deficit irrigation regime. In summary, this work shows the interaction between irrigation regime and high temperature on the control of berry ripening.

Modelling average maximum daily temperature using r largest order statistics: An application to South African data

PubMed Central

2018-01-01

Natural hazards (events that may cause actual disasters) are established in the literature as major causes of various massive and destructive problems worldwide. The occurrences of earthquakes, floods and heat waves affect millions of people through several impacts. These include cases of hospitalisation, loss of lives and economic challenges. The focus of this study was on the risk reduction of the disasters that occur because of extremely high temperatures and heat waves. Modelling average maximum daily temperature (AMDT) guards against the disaster risk and may also help countries towards preparing for extreme heat. This study discusses the use of the r largest order statistics approach of extreme value theory towards modelling AMDT over the period of 11 years, that is, 2000–2010. A generalised extreme value distribution for r largest order statistics is fitted to the annual maxima. This is performed in an effort to study the behaviour of the r largest order statistics. The method of maximum likelihood is used in estimating the target parameters and the frequency of occurrences of the hottest days is assessed. The study presents a case study of South Africa in which the data for the non-winter season (September–April of each year) are used. The meteorological data used are the AMDT that are collected by the South African Weather Service and provided by Eskom. The estimation of the shape parameter reveals evidence of a Weibull class as an appropriate distribution for modelling AMDT in South Africa. The extreme quantiles for specified return periods are estimated using the quantile function and the best model is chosen through the use of the deviance statistic with the support of the graphical diagnostic tools. The Entropy Difference Test (EDT) is used as a specification test for diagnosing the fit of the models to the data.

Herbage intake and milk yield in Comisana ewes as effect of 4 vs 7 h of grazing during late lactation.

PubMed

Valenti, Bernardo; Marletta, Donata; De Angelis, Anna; Di Paola, Fortunato; Bordonaro, Salvatore; Avondo, Marcella

2017-06-01

Thirty-two Comisana ewes at late lactation were used in two trials carried out during late spring in 2 consecutive years, with the aim to evaluate the effect of the duration of grazing on herbage intake and performance. In each trial, 16 pluriparous Comisana lactating ewes were equally divided into two groups which grazed in two separate areas of natural pasture from 11:00 to 15:00 h (group 4H) or from 10:00 to 17:00 (group 7H). A concentrate mixture (500 g/day) was also offered to each ewe. The mean maximum temperature was, respectively, 23.5 ± 3.8 °C during experiment 1 and 27.0 ± 3.1 °C during experiment 2. Probably as a consequence of the differences in climatic conditions, the results on herbage intake and milk production were different during the two trials. Herbage dry matter intake was not affected by the duration of grazing during trial 1, whereas it was significantly lower in 4H group compared to that in 7H group (0.67 vs 1.02 kg/day; P < 0.001) during trial 2. It could be hypothesised that while with lower environmental temperature (trial 1), the 4H ewes were able to reach good intake levels despite grazing during the hottest hours; with higher temperatures throughout the trial (trial 2), the 4H ewes reduced ingestion. Milk production was higher in 4H group during trial 1 (778 vs 707 g/day; P = 0.006), whereas it was not affected by the number of hours of grazing during trial 2, despite the higher intake levels reached by the 7H group. In conclusion, 3 extra hours of grazing for ewes at late lactation on a low quality pasture could be nullified in terms of yield response.

Urban climate effects on extreme temperatures in Madison, Wisconsin, USA

NASA Astrophysics Data System (ADS)

Schatz, Jason; Kucharik, Christopher J.

2015-09-01

As climate change increases the frequency and intensity of extreme heat, cities and their urban heat island (UHI) effects are growing, as are the urban populations encountering them. These mutually reinforcing trends present a growing risk for urban populations. However, we have limited understanding of urban climates during extreme temperature episodes, when additional heat from the UHI may be most consequential. We observed a historically hot summer and historically cold winter using an array of up to 150 temperature and relative humidity sensors in and around Madison, Wisconsin, an urban area of population 402 000 surrounded by lakes and a rural landscape of agriculture, forests, wetlands, and grasslands. In the summer of 2012 (third hottest since 1869), Madison’s urban areas experienced up to twice as many hours ⩾32.2 °C (90 °F), mean July TMAX up to 1.8 °C higher, and mean July TMIN up to 5.3 °C higher than rural areas. During a record setting heat wave, dense urban areas spent over four consecutive nights above the National Weather Service nighttime heat stress threshold of 26.7 °C (80 °F), while rural areas fell below 26.7 °C nearly every night. In the winter of 2013-14 (coldest in 35 years), Madison’s most densely built urban areas experienced up to 40% fewer hours ⩽-17.8 °C (0 °F), mean January TMAX up to 1 °C higher, and mean January TMIN up to 3 °C higher than rural areas. Spatially, the UHI tended to be most intense in areas with higher population densities. Temporally, both daytime and nighttime UHIs tended to be slightly more intense during more-extreme heat days compared to average summer days. These results help us understand the climates for which cities must prepare in a warming, urbanizing world.

Flash Mixing of the White Dwarf Cooling Curve Spectroscopic Confirmation in NGC 2808

NASA Technical Reports Server (NTRS)

Brown, Thomas M.; Lanz, Thierry; Sweigart, Allen V.; Cracraft, Misty; Hubeny, Ivan; Landsman, Wayne B.

2009-01-01

We present new HST far-UV spectroscopy of two dozen hot evolved stars in NGC 2808, a massive globular cluster with a large population of "blue-hook" stars. The blue-hook stars are found in ultraviolet color-magnitude diagrams of the most massive globular clusters, where they fall at luminosities immediately below the hot end of the horizontal branch (HB), in a region of the HR diagram unexplained by canonical stellar evolution theory. Using new theoretical evolutionary and atmospheric models, we have shown that these subluminous HB stars are very likely the progeny of stars that undergo extensive internal mixing during a late He-core flash on the white dwarf cooling curve. This flash mixing leads to hotter temperatures and an enormous enhancement of the surface He and C abundances; the hotter temperatures and associated decrease in the hydrogen opacity shortward of the Lyman limit makes the stars brighter in the extreme UV but appear sub luminous in the UV and optical. Our far-UV spectroscopy demonstrates that, relative to normal HB stars at the same color, the blue-hook stars of NGC 2808 are hotter and greatly enhanced in He and C, thus providing unambiguous evidence of flash mixing in the subluminous population. Although the C abundance in the blue-hook stars is orders of magnitude larger than that in the normal HB stars, the atmospheric C abundance in both the blue-hook and normal HB stars appears to be affected by gravitational settling. The abundance variations seen in C, Si, and the Fe-peak elements indicate that atmospheric diffusion is at play in our sample, with all of our hot subdwarfs at 25,000 K to 50,000 K exhibiting large enhancements of the iron-peak elements. The hottest subdwarfs in our blue-hook sample may be pulsators, given that they fall in the temperature range of newly-discovered pulsating subdwarfs in omega Cen.

Carryover effects and climatic conditions influence the postfledging survival of greater sage-grouse

USGS Publications Warehouse

Blomberg, Erik J.; Sedinger, James S.; Gibson, Daniel; Coates, Peter S.; Casazza, Michael L.

2014-01-01

Prebreeding survival is an important life history component that affects both parental fitness and population persistence. In birds, prebreeding can be separated into pre- and postfledging periods; carryover effects from the prefledging period may influence postfledging survival. We investigated effects of body condition at fledging, and climatic variation, on postfledging survival of radio-marked greater sage-grouse (Centrocercus urophasianus) in the Great Basin Desert of the western United States. We hypothesized that body condition would influence postfledging survival as a carryover effect from the prefledging period, and we predicted that climatic variation may mediate this carryover effect or, alternatively, would act directly on survival during the postfledging period. Individual body condition had a strong positive effect on postfledging survival of juvenile females, suggesting carryover effects from the prefledging period. Females in the upper 25th percentile of body condition scores had a postfledging survival probability more than twice that (Φ = 0.51 ± 0.06 SE) of females in the bottom 25th percentile (Φ = 0.21 ± 0.05 SE). A similar effect could not be detected for males. We also found evidence for temperature and precipitation effects on monthly survival rates of both sexes. After controlling for site-level variation, postfledging survival was nearly twice as great following the coolest and wettest growing season (Φ = 0.77 ± 0.05 SE) compared with the hottest and driest growing season (Φ = 0.39 ± 0.05 SE). We found no relationships between individual body condition and temperature or precipitation, suggesting that carryover effects operated independently of background climatic variation. The temperature and precipitation effects we observed likely produced a direct effect on mortality risk during the postfledging period. Conservation actions that focus on improving prefledging habitat for sage-grouse may have indirect benefits to survival during postfledging, due to carryover effects between the two life phases.

Temperature Dependence of Mineral Solubility in Water. Part 3. Alkaline and Alkaline Earth Sulfates

NASA Astrophysics Data System (ADS)

Krumgalz, B. S.

2018-06-01

The databases of alkaline and alkaline earth sulfate solubilities in water at various temperatures were created using experimental data from the publications over about the last two centuries. Statistical critical evaluation of the created databases was produced since there were enough independent data sources to justify such evaluation. The reliable experimental data were adequately described by polynomial expressions over various temperature ranges. Using the Pitzer approach for ionic activity and osmotic coefficients, the thermodynamic solubility products for the discussed minerals have been calculated at various temperatures and represented by polynomial expressions.

Temperature Dependence of Mineral Solubility in Water. Part 2. Alkaline and Alkaline Earth Bromides

NASA Astrophysics Data System (ADS)

Krumgalz, B. S.

2018-03-01

Databases of alkaline and alkaline earth bromide solubilities in water at various temperatures were created using experimental data from publications over about the last two centuries. Statistical critical evaluation of the created databases was produced since there were enough independent data sources to justify such evaluation. The reliable experimental data were adequately described by polynomial expressions over various temperature ranges. Using the Pitzer approach for ionic activity and osmotic coefficients, the thermodynamic solubility products for the discussed bromide minerals have been calculated at various temperature intervals and also represented by polynomial expressions.

An Empirical Examination of Reverse Auction Appropriateness in B2B Source Selection

DTIC Science & Technology

2006-01-01

Measures of Marketing Constructs," Journal of Marketing Research , Vol. 16, No.2, pp. 64 - 73. Cohn, L. (2000), "B2B: The Hottest Net Bet Yet...34 Psycholgical Bulletin, Vol. 103, No.3, pp. 411-423. Armstrong, J.S. and T.S. Overton (1977), "Estimating Nonresponse Bias in Mail Surveys," Journal of Marketing ... Research , Vol.14, No.3, pp. 396-402. Bagozzi, R. (1983), "Issues in the Application of Covariance Structure Analysis: A Further Comment," Journal of

Sunrayce 93: The hottest new sport on campus. Technical report

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

Not Available

1994-05-01

The solar powered electric vehicle race began in Arlington, Texas on June 20, 1993 and finished 7 days later in Minneapolis, Minnesota. Thirty four teams from Universities across the United States and Puerto Rico completed the race out of thirty six entries. The race demonstrated the viability of sunlight powered vehicles as the better average daily speeds were in excess of 50 miles an hour. Even in the rain, most average speeds were in excess of 15 miles an hour. Analyzed results, photographs, and project details are included. (GHH)

Sale of prescription drugs over the Internet.

PubMed

Armstrong, K; Bloom, B S

1999-01-01

Online drugstores represent one of the hottest categories in electronic commerce. The Internet offers great promise in expanding access to prescription drugs for the disabled, the elderly, and people living in rural areas. But with this promise comes the danger of eliminating the safeguards that protect consumers from inappropriate use of medications and adverse drug events. This Issue Brief highlights two studies that investigate the availability of prescription drugs over the Internet, and focuses on the alarming ease with which consumers can obtain drugs without seeing a physician or a pharmacist.

Eliminate background interference from latent fingerprints using ultraviolet multispectral imaging

NASA Astrophysics Data System (ADS)

Huang, Wei; Xu, Xiaojing; Wang, Guiqiang

2014-02-01

Fingerprints are the most important evidence in crime scene. The technology of developing latent fingerprints is one of the hottest research areas in forensic science. Recently, multispectral imaging which has shown great capability in fingerprints development, questioned document detection and trace evidence examination is used in detecting material evidence. This paper studied how to eliminate background interference from non-porous and porous surface latent fingerprints by rotating filter wheel ultraviolet multispectral imaging. The results approved that background interference could be removed clearly from latent fingerprints by using multispectral imaging in ultraviolet bandwidth.

Distribution and decline of human pathogenic bacteria in soil after application in irrigation water and the potential for soil-splash-mediated dispersal onto fresh produce.

PubMed

Monaghan, J M; Hutchison, M L

2012-05-01

To improve our understanding of the survival and splash-mediated transfer of zoonotic agents and faecal indicator bacteria introduced into soils used for crop cultivation via contaminated irrigation waters. Zoonotic agents and an Escherichia coli marker bacterium were inoculated into borehole water, which was applied to two different soil types in early-, mid- and late summer. Decline of the zoonotic agents was influenced by soil type. Marker bacteria applied to columns of two soil types in irrigation water did not concentrate at the surface of the soils. Decline of zoonotic agents at the surface was influenced by soil type and environmental conditions. Typically, declines were rapid and bacteria were not detectable after 5 weeks. Selective agar strips were used to determine that the impact of water drops 24-87 μl could splash marker bacteria from soil surfaces horizontal distances of at least 25 cm and heights of 20 cm. Soil splash created by rain-sized water droplets can transfer enteric bacteria from soil to ready-to-eat crops. Persistence of zoonotic agents was reduced at the hottest part of the growing season when irrigation is most likely. Soil splash can cause crop contamination. We report the penetration depths and seasonally influenced declines of bacteria applied in irrigation water into two soil types. © 2012 The Authors. Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

Chiliques Volcano, Chile

NASA Image and Video Library

2002-04-19

A January 6, 2002 ASTER nighttime thermal infrared image of Chiliques volcano in Chile shows a hot spot in the summit crater and several others along the upper flanks of the edifice, indicating new volcanic activity. Examination of an earlier nighttime thermal infrared image from May 24, 2000 showed no thermal anomaly. Chiliques volcano was previously thought to be dormant. Rising to an elevation of 5778 m, Chiliques is a simple stratovolcano with a 500-m-diameter circular summit crater. This mountain is one of the most important high altitude ceremonial centers of the Incas. It is rarely visited due to its difficult accessibility. Climbing to the summit along Inca trails, numerous ruins are encountered; at the summit there are a series of constructions used for rituals. There is a beautiful lagoon in the crater that is almost always frozen. The daytime image was acquired on November 19, 2000 and was created by displaying ASTER bands 1,2 and 3 in blue, green and red. The nighttime image was acquired January 6, 2002, and is a color-coded display of a single thermal infrared band. The hottest areas are white, and colder areas are darker shades of red. Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude. Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude. http://photojournal.jpl.nasa.gov/catalog/PIA03493

Low temperature reactive bonding

DOEpatents

Makowiecki, D.M.; Bionta, R.M.

1995-01-17

The joining technique is disclosed that requires no external heat source and generates very little heat during joining. It involves the reaction of thin multilayered films deposited on faying surfaces to create a stable compound that functions as an intermediate or braze material in order to create a high strength bond. While high temperatures are reached in the reaction of the multilayer film, very little heat is generated because the films are very thin. It is essentially a room temperature joining process. 5 figures.

Heat-Related Mortality in India: Excess All-Cause Mortality Associated with the 2010 Ahmedabad Heat Wave

PubMed Central

Azhar, Gulrez Shah; Mavalankar, Dileep; Nori-Sarma, Amruta; Rajiva, Ajit; Dutta, Priya; Jaiswal, Anjali; Sheffield, Perry; Knowlton, Kim; Hess, Jeremy J.; Azhar, Gulrez Shah; Deol, Bhaskar; Bhaskar, Priya Shekhar; Hess, Jeremy; Jaiswal, Anjali; Khosla, Radhika; Knowlton, Kim; Mavalankar, Mavalankar; Rajiva, Ajit; Sarma, Amruta; Sheffield, Perry

2014-01-01

Introduction In the recent past, spells of extreme heat associated with appreciable mortality have been documented in developed countries, including North America and Europe. However, far fewer research reports are available from developing countries or specific cities in South Asia. In May 2010, Ahmedabad, India, faced a heat wave where the temperatures reached a high of 46.8°C with an apparent increase in mortality. The purpose of this study is to characterize the heat wave impact and assess the associated excess mortality. Methods We conducted an analysis of all-cause mortality associated with a May 2010 heat wave in Ahmedabad, Gujarat, India, to determine whether extreme heat leads to excess mortality. Counts of all-cause deaths from May 1–31, 2010 were compared with the mean of counts from temporally matched periods in May 2009 and 2011 to calculate excess mortality. Other analyses included a 7-day moving average, mortality rate ratio analysis, and relationship between daily maximum temperature and daily all-cause death counts over the entire year of 2010, using month-wise correlations. Results The May 2010 heat wave was associated with significant excess all-cause mortality. 4,462 all-cause deaths occurred, comprising an excess of 1,344 all-cause deaths, an estimated 43.1% increase when compared to the reference period (3,118 deaths). In monthly pair-wise comparisons for 2010, we found high correlations between mortality and daily maximum temperature during the locally hottest “summer” months of April (r = 0.69, p<0.001), May (r = 0.77, p<0.001), and June (r = 0.39, p<0.05). During a period of more intense heat (May 19–25, 2010), mortality rate ratios were 1.76 [95% CI 1.67–1.83, p<0.001] and 2.12 [95% CI 2.03–2.21] applying reference periods (May 12–18, 2010) from various years. Conclusion The May 2010 heat wave in Ahmedabad, Gujarat, India had a substantial effect on all-cause excess mortality, even in this city where hot temperatures prevail through much of April-June. PMID:24633076

Age, origin, and thermal evolution of the ultra-fresh 1.9 Ga Winnipegosis Komatiites, Manitoba, Canada

NASA Astrophysics Data System (ADS)

Waterton, Pedro; Pearson, D. Graham; Kjarsgaard, Bruce; Hulbert, Larry; Locock, Andrew; Parman, Stephen; Davis, Bill

2017-01-01

The Proterozoic spans the longest portion of earth's history, yet in contrast to the Archaean, the record of komatiites and related high MgO igneous rocks from this Eon is sparse. This paper describes the pristine Palaeoproterozoic Winnipegosis Komatiites, from Manitoba, Canada, which form part of the Circum-Superior Belt large igneous province. We present a comprehensive petrographical investigation, mineral and bulk rock geochemistry, and Al-in-olivine thermometry for the Winnipegosis Komatiites, along with new U-Pb SHRIMP dating of zircons from a mafic unit, which yield an age of 1870.3 ± 7.1 Ma for the Winnipegosis Komatiite Belt. The komatiites are Al-undepleted and dominated by massive olivine porphyritic flows with a median thickness of 6 m. Differentiated flows containing layers of olivine spinifex are present, but rare. Trace element data indicate the komatiites were derived from depleted mantle, and subsequently contaminated with 2-3% continental crust. Temperatures from Al-in-olivine thermometry are consistent with a nominally dry melt, and combined with olivine-melt Mg-Fe partitioning, suggest a parental melt with 24 wt% MgO and a liquidus (olivine) temperature of 1501 °C, approximately 100 °C cooler than their hottest Archaean counterparts. At 1424 °C chromite joined olivine as a crystallising phase. Olivine and chromite phenocrysts were re-mixed with residual melt shortly before or during komatiite eruption, which occurred by the time the magma had cooled to 1321 °C. Combined geochemical and geological evidence requires that the Winnipegosis Komatiites erupted onto rifting continental crust. Their high liquidus temperatures require anomalously hot mantle. Considering the Winnipegosis Komatiites in the context of the broader Circum-Superior Belt, we suggest that these magmas formed from a mantle plume that was deflected towards the margins of the Superior craton by strong gradients in lithospheric thickness. This interpretation of the mode of formation of the Circum-Superior Belt casts doubt on ambient mantle potential temperatures as high as 1600 °C during the Proterozoic.

Influence of swimming time in alleviating the deleterious effects of hot summer on growing Muscovy duck performance.

PubMed

Farghly, Mohamed F A; Mahrose, Khalid M; Ullah, Zafar; Rehman, Zaib Ur; Ding, Chan

2017-09-01

This experiment was conducted to observe the effects of varying swimming times (ST) of Muscovy ducks, raised in an open-sided house, in alleviating the deleterious effects of high temperature in hotter times of the day in the summer season on growth performance (body weight, average daily gain, feed consumption, and feed conversion ratio), carcass characteristics, body temperature, and some health aspects. We hypothesized that swimming times during the hottest periods of the day would show different performances. To test this hypothesis a total of 180 Muscovy ducklings were randomly distributed into 4 equal groups in a completely randomized design experiment. All groups were raised under similar housing conditions. Birds of the first group (C) were raised in the indoor system and had no access to a swimming pond. While all birds of the second, third, and fourth groups (T1, T2, and T3) had access to a swimming pond during 10:00 to 12:00 h, 12:00 to 14:00 h, and 14:00 to 16:00 h, respectively. The swimming pond (dimensions of 30 m length × 10 m width × 3 m depth with cement floor) was located in the front of the house. Vaccination and medical programs were undertaken according to the different ages under supervision of a licensed veterinarian. The obtained results indicated that swimming during 12:00 to 14:00 h improved (P < 0.05) growth performance, dressed carcass, meat tenderness, lymphocyte, heterophils/lymphocytes ratio, body temperature, and mortality rate of Muscovy ducks. However, bone measurement, plumage conditions, foot pad dermatitis, hock discoloration, breast blisters score, and blood hematocrit values were insignificantly better in the group with access to the swimming pond during 12:00 to 14:00 h. In conclusion, raising ducks during hot conditions in an open-sided house with access to a swimming pond at 12:00 to 14:00 h is highly recommended due to the high BW, better immunity, decreased mortality rate, and low body temperature of ducks which was positively reflected in the health condition. © 2017 Poultry Science Association Inc.

Thermal Barrier Coatings Chemically and Mechanically Resistant to High Temperature Attack by Molten Ashes

NASA Astrophysics Data System (ADS)

Gledhill, Andrew

Thermal barrier coatings (TBCs) are ceramic coatings used on component in the hottest sections of gas turbine engines, used for power generation and aviation. These coatings insulate the underlying metal components and allow for much higher engine operating temperatures, improving the engine efficiency. These increase temperatures engender a new set of materials problems for TBCs. Operating temperatures in engines are now high enough for silicate impurities, either present in the fuel or ingested into the engines, to melt and adhere to the surface of the TBCs. The effects of four such impurities, two coal fly ashes, a petroleum coke-fly ash blend, and volcanic ash from the Eyjafjallajokull volcano were tested with conventional yttria-stabilized zirconia (YSZ) coatings, and found to penetrate through the entire thickness of the coating. This penetration reduces the strain tolerance of the coatings, and can result in premature failure. Testing on a newly built thermal gradient burner rig with simultaneous injection of ash impurities has shown a reduction of life up to 99.6% in these coatings when ash is present. Coatings of an alternative ceramic, gadolinium zirconate (Gd2Zr 2O7), were found to form a dense reaction layer with each of these impurities, preventing further penetration of the molten ash. This dense layer also reduces the strain tolerance, but these coatings were found to have a significantly higher life than the YSZ coatings. Testing with a small amount of ash baked onto the samples showed thirteen times the life of YSZ coatings. When the ash is continuously sprayed onto the hot sample, the life of the Gd2Zr2O7 coatings was nearly twice that of the YSZ. Finally, a delamination model was employed to explain the degradation of both types of coatings. This elastic model that takes into account the degree of penetration, differential cooling in thermal gradient testing, and thermal expansion mismatch with the underlying substrate, predicted the failure of YSZ coatings with the observed degree of penetration. The model shows that deposition optimization can be employed to further enhance the life of Gd 2Zr2O7coatings.

Measuring Volcanic Thermal Output

NASA Astrophysics Data System (ADS)

Reath, K.

2017-12-01

In most cases, volcanic eruptions are preceded by some form of unrest that can be used as an early warning sign of an impending eruption or provide insight into changing hazards during an eruption, contingent upon this unrest being properly monitored and understood. Many ground and satellite monitoring techniques have been developed to identify the varying types volcanic unrest, including seismic, degassing, deformation, and thermal measurements. High spatial resolution thermal infrared (TIR) remote sensing, such as the thermal images acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor, have proven particularly effective at identifying and tracking variations in thermal unrest in the form of volcanic thermal anomalies. However, the majority of ASTER thermal anomaly studies have focused on tracking the variations in the temperature of the hottest pixel above background in the anomaly. Whereas, this remains a valid method as it reveals valuable information about variations occurring at the main vent of a volcano, it does not incorporate the thermal output of the entire anomaly, which typically expands beyond one pixel due to the heating of the surrounding area. By developing a weighted area method that considers both the thermal anomaly area and temperature the total thermal output of an anomaly can be measured. It some case studies, such as the period before the 2016 Sabancaya eruption, both temperature and area increase before an eruptive event. Here, the weighted area methods demonstrates a clearer increase in thermal unrest than the traditional above temperature method. In other case studies, such as the thermal anomaly observed at Lascar volcano, the area of the anomaly remains relatively constant. This limits the variation in values between these two methods. However, by incorporating data from both of these methods, valuable interpretations can be made about the dynamics of the main vent where compared to the full thermal system. A variety of volcanoes will be demonstrated in this presentation to understand the conditions where this technique is most helpful and how the weighted area method enables a more complete analysis of the volcanic processes occurring both before and during eruption.

Shiveluch and Klyuchevskaya Volcanoes

NASA Technical Reports Server (NTRS)

2007-01-01

A distance of about 80 kilometers (50 miles) separates Shiveluch and Klyuchevskaya Volcanoes on Russia's Kamchatka Peninsula. Despite this distance, however, the two acted in unison on April 26, 2007, when the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite caught them both erupting simultaneously. ASTER 'sees' a slightly different portion of the light spectrum than human eyes. Besides a portion of visible light, ASTER detects thermal energy, meaning it can detect volcanic activity invisible to human eyes. Inset in each image above is a thermal infrared picture of the volcano's summit. In these insets, dark red shows where temperatures are coolest, and yellowish-white shows where temperatures are hottest, heated by molten lava. Both insets show activity at the crater. In the case of Klyuchevskaya, some activity at the crater is also visible in the larger image. In the larger images, the landscapes around the volcanoes appear in varying shades of blue-gray. Dark areas on the snow surface are likely stains left over from previous eruptions of volcanic ash. Overhead, clouds dot the sky, casting their shadows on the snow, especially southeast of Shiveluch and northeast of Klyuchevskaya. To the northwest of Klyuchevskaya is a large bank of clouds, appearing as a brighter white than the snow surface. Shiveluch (sometimes spelled Sheveluch) and Klyuchevskaya (sometimes spelled Klyuchevskoy or Kliuchevskoi) are both stratovolcanoes composed of alternating layers of hardened lava, solidified ash, and rocks from earlier eruptions. Both volcanoes rank among Kamchatka's most active. Because Kamchatka is part of the Pacific 'Ring of Fire,' the peninsula experiences regular seismic activity as the Pacific Plate slides below other tectonic plates in the Earth's crust. Large-scale plate tectonic activity causing simultaneous volcanic eruptions in Kamchatka is not uncommon.

Dust in a Type Ia Supernova Progenitor: Spitzer Spectroscopy of Kepler's Supernova Remnant

NASA Technical Reports Server (NTRS)

Williams, Brian J.; Borkowski, Kazimierz; Reynolds, Stephen P.; Ghavamian, Parviz; Blair, William P.; Long, Knox S.; Sankrit, Ravi

2012-01-01

Characterization of the relatively poorly-understood progenitor systems of Type Ia supernovae is of great importance in astrophysics, particularly given the important cosmological role that these supernovae play. Kepler's Supernova Remnant, the result of a Type Ia supernova, shows evidence for an interaction with a dense circumstellar medium (CSM), suggesting a single-degenerate progenitor system. We present 7.5-38 micron IR spectra of the remnant, obtained with the Spitzer Space Telescope, dominated by emission from warm dust. Broad spectral features at 10 and 18 micron, consistent with various silicate particles, are seen throughout. These silicates were likely formed in the stellar outflow from the progenitor system during the AGB stage of evolution, and imply an oxygen-rich chemistry. In addition to silicate dust, a second component, possibly carbonaceous dust, is necessary to account for the short-wavelength IRS and IRAC data. This could imply a mixed chemistry in the atmosphere of the progenitor system. However, non-spherical metallic iron inclusions within silicate grains provide an alternative solution. Models of collisionally-heated dust emission from fast shocks (> 1000 km/s) propagating into the CSM can reproduce the majority of the emission associated with non-radiative filaments, where dust temperatures are approx 80-100 K, but fail to account for the highest temperatures detected, in excess of 150 K. We find that slower shocks (a few hundred km/s) into moderate density material (n(sub o) approx 50-100 / cubic cm) are the only viable source of heating for this hottest dust. We confirm the finding of an overall density gradient, with densities in the north being an order of magnitude greater than those in the south.

Multi-thermal observations of the 2010 October 16 flare:heating of a ribbon via loops, or a blast wave?

NASA Astrophysics Data System (ADS)

Christe, Steven; Inglis, A.; Aschwanden, M.; Dennis, B.

2011-05-01

On 2010 October 16th SDO/AIA observed its first flare using automatic exposure control. Coincidentally, this flare also exhibited a large number of interesting features. Firstly, a large ribbon significantly to the solar west of the flare kernel was ignited and was visible in all AIA wavelengths, posing the question as to how this energy was deposited and how it relates to the main flare site. A faint blast wave also emanates from the flare kernel, visible in AIA and observed traveling to the solar west at an estimated speed of 1000 km/s. This blast wave is associated with a weak white-light CME observed with STEREO B and a Type II radio burst observed from Green Bank Observatory (GBSRBS). One possibility is that this blast wave is responsible for the heating of the ribbon. However, closer scrutiny reveals that the flare site and the ribbon are in fact connected magnetically via coronal loops which are heated during the main energy release. These loops are distinct from the expected hot, post-flare loops present within the main flare kernel. RHESSI spectra indicate that these loops are heated to approximately 10 MK in the immediate flare aftermath. Using the multi-temperature capabilities of AIA in combination with RHESSI, and by employing the cross-correlation mapping technique, we are able to measure the loop temperatures as a function of time over several post-flare hours and hence measure the loop cooling rate. We find that the time delay between the appearance of loops in the hottest channel, 131 A, and the cool 171 A channel, is 70 minutes. Yet the causality of this event remains unclear. Is the ribbon heated via these interconnected loops or via a blast wave?

Is shade beneficial for mediterranean shrubs experiencing periods of extreme drought and late-winter frosts?

PubMed

Valladares, Fernando; Zaragoza-Castells, Joana; Sánchez-Gómez, David; Matesanz, Silvia; Alonso, Beatriz; Portsmuth, Angelika; Delgado, Antonio; Atkin, Owen K

2008-12-01

Plants are naturally exposed to multiple, frequently interactive stress factors, most of which are becoming more severe due to global change. Established plants have been reported to facilitate the establishment of juvenile plants, but net effects of plant-plant interactions are difficult to assess due to complex interactions among environmental factors. An investigation was carried out in order to determine how two dominant evergreen shrubs (Quercus ilex and Arctostaphylos uva-ursi) co-occurring in continental, Mediterranean habitats respond to multiple abiotic stresses and whether the shaded understorey conditions ameliorate the negative effects of drought and winter frosts on the physiology of leaves. Microclimate and ecophysiology of sun and shade plants were studied at a continental plateau in central Spain during 2004-2005, with 2005 being one of the driest and hottest years on record; several late-winter frosts also occurred in 2005. Daytime air temperature and vapour pressure deficit were lower in the shade than in the sun, but soil moisture was also lower in the shade during the spring and summer of 2005, and night-time temperatures were higher in the shade. Water potential, photochemical efficiency, light-saturated photosynthesis, stomatal conductance and leaf 13C composition differed between sun and shade individuals throughout the seasons, but differences were species specific. Shade was beneficial for leaf-level physiology in Q. ilex during winter, detrimental during spring for both species, and of little consequence in summer. The results suggest that beneficial effects of shade can be eclipsed by reduced soil moisture during dry years, which are expected to be more frequent in the most likely climate change scenarios for the Mediterranean region.

Is Shade Beneficial for Mediterranean Shrubs Experiencing Periods of Extreme Drought and Late-winter Frosts?

PubMed Central

Valladares, Fernando; Zaragoza-Castells, Joana; Sánchez-Gómez, David; Matesanz, Silvia; Alonso, Beatriz; Portsmuth, Angelika; Delgado, Antonio; Atkin, Owen K.

2008-01-01

Background and Aims Plants are naturally exposed to multiple, frequently interactive stress factors, most of which are becoming more severe due to global change. Established plants have been reported to facilitate the establishment of juvenile plants, but net effects of plant–plant interactions are difficult to assess due to complex interactions among environmental factors. An investigation was carried out in order to determine how two dominant evergreen shrubs (Quercus ilex and Arctostaphylos uva-ursi) co-occurring in continental, Mediterranean habitats respond to multiple abiotic stresses and whether the shaded understorey conditions ameliorate the negative effects of drought and winter frosts on the physiology of leaves. Methods Microclimate and ecophysiology of sun and shade plants were studied at a continental plateau in central Spain during 2004–2005, with 2005 being one of the driest and hottest years on record; several late-winter frosts also occurred in 2005. Key Results Daytime air temperature and vapour pressure deficit were lower in the shade than in the sun, but soil moisture was also lower in the shade during the spring and summer of 2005, and night-time temperatures were higher in the shade. Water potential, photochemical efficiency, light-saturated photosynthesis, stomatal conductance and leaf 13C composition differed between sun and shade individuals throughout the seasons, but differences were species specific. Shade was beneficial for leaf-level physiology in Q. ilex during winter, detrimental during spring for both species, and of little consequence in summer. Conclusions The results suggest that beneficial effects of shade can be eclipsed by reduced soil moisture during dry years, which are expected to be more frequent in the most likely climate change scenarios for the Mediterranean region. PMID:18819947

Changes in hot spring temperature and hydrogeology of the Alpine Fault hanging wall, New Zealand, induced by distal South Island earthquakes

NASA Astrophysics Data System (ADS)

Cox, S.; Menzies, C. D.; Sutherland, R.; Denys, P. H.; Chamberlain, C. J.; Teagle, D. A. H.

2014-12-01

In response to large distant earthquakes Copland hot spring cooled c.1 °C and changed fluid chemistry. Thermal springs in the Southern Alps, New Zealand, originate through penetration of fluids into a thermal anomaly generated by rapid uplift and exhumation on the Alpine Fault. Copland hot spring (43.629S, 169.946E) is one of the most vigorously flowing, hottest of the springs, discharging strongly effervescent CO2-rich 56-58 °C water at 6 ± 1 Ls-1. Shaking from the Mw7.8 Dusky Sound (Fiordland) 2009 and Mw7.1 Darfield (Canterbury) 2010 earthquakes, 350 and 180 km from the spring respectively, resulted in a characteristic c. 1 °C delayed-cooling over five days. The cooling responses occurred at low shaking intensities (MM III-IV) and seismic energy densities (~10-1 Jm-3) from intermediate-field distances, independent of variations in spectral frequency, without the need for post-seismic recovery before the next cooling occurred. Such shaking can be expected approximately every 1-10 years in central Southern Alps. Observed temperature and fluid chemistry responses are inferred to reflect subtle changes in the fracture permeability of schist mountains adjacent to the spring. Relatively low intensity shaking induced small permanent 10-7-10-6 strains across the Southern Alps - opening fractures which enhance mixing of relatively cool near-surface groundwater with upwelling hot water. Hydrothermal systems situated in places of active deformation, tectonic and topographic stress may be particularly susceptible to earthquake-induced transience, that if monitored may provide important information on difficult to measure hydrogeological properties within active orogens.

Seasonal variations in VOC emission rates from gorse (Ulex europaeus)

NASA Astrophysics Data System (ADS)

Boissard, C.; Cao, X.-L.; Juan, C.-Y.; Hewitt, C. N.; Gallagher, M.

Seasonal variations of biogenic volatile organic compound (VOC) emission rates and standardised emission factors from gorse (Ulex europaeus) have been measured at two sites in the United Kingdom, from October 1994 to September 1995, within temperature and PAR conditions ranging from 3 to 34°C and 10-1300 μmol m-2 s-1, respectively. Isoprene was the dominant emitted compound with a relative composition fluctuating from 7% of the total VOC (winter) to 97% (late summer). The monoterpenes α-pinene, camphene, sabinene, β-pinene, myrcene, limonene, trans-ocimene and γ-terpinene were also emitted, with α-pinene being the dominant monoterpene during most the year. Trans-ocimene represented 33-66% of the total monoterpene during the hottest months from June to September. VOC emissions were found to be accurately predicted using existing algorithms. Standard (normalised) emission factors of VOCs from gorse were calculated using experimental parameters measured during the experiment and found to fluctuate with season, from 13.3±2.1 to 0.1±0.1 μg C (g dwt)-1 h-1 in August 1995 and January 1995, respectively, for isoprene, and from 2.5±0.2 to 0.4±0.2 μg C (g dwt)-1 h-1 in July and November 1995, respectively, for total monoterpenes. No simple clear relation was found to allow prediction of these seasonal variations with respect to temperature and light intensity. The effects of using inappropriate algorithms to derive VOC fluxes from gorse were assessed for isoprene and monoterpenes. Although on an annual basis the discrepancies are not significant, monthly estimation of isoprene were found to be overestimated by more than a factor of 50 during wintertime when the seasonality of emission factors is not considered.

The Thermal States of Accreting Planets: From Mars-like Embryos to a MAD Earth

NASA Astrophysics Data System (ADS)

Stewart, S. T.; Lock, S. J.

2015-12-01

The thermal states of rocky planets can vary widely during the process of accretion. The thermal structure affects several major processes on the growing planet, including the mechanics of core formation, pressure-temperature conditions for metal-silicate equilibration, mixing, and atmospheric erosion. Because impact energy is distributed heterogeneously, accretional energy is preferentially deposited in the gravitationally re-equilibrated outer layers of the planet for both small and giant impacts. The resulting stably stratified structure inhibits complete mixing within the mantle. Initially, the specific energy of giant impacts between Mars-mass embryos leads to melting of the mantle. However, as planet formation progresses, the specific energies of giant impacts increase and can drive the mantle into a transient supercritical state. In the hottest regions of the planet, metal and silicates are miscible, and metal exsolution occurs as the structure cools. The cooling time of the supercritical structure is typically longer than the timescale for metal segregation to the core. Thus, these high temperature excursions during planet formation are significant for understanding metal-silicate equilibration. Furthermore, when a supercritical planet is also rapidly rotating, the mantle, atmosphere and disk (MAD) form a continuous dynamic and thermodynamic structure. Lunar origin by condensation from a MAD Earth can explain the major characteristics of the Moon (Lock et al., this meeting). One of the greatest uncertainties in understanding the thermal states of planets during accretion is the changing composition and mass of the atmosphere. After the dispersal of the solar nebula, the thermal boundary condition imposed by the atmosphere can vary between silicate vapor and condensed ices. The coupled problem of atmospheric origin and planetary accretion can be used to constrain the many uncertainties in the growth and divergence of the terrestrial planets in our solar system.

Marked annual coral bleaching resilience of an inshore patch reef in the Florida Keys: A nugget of hope, aberrance, or last man standing?

NASA Astrophysics Data System (ADS)

Gintert, Brooke E.; Manzello, Derek P.; Enochs, Ian C.; Kolodziej, Graham; Carlton, Renée; Gleason, Arthur C. R.; Gracias, Nuno

2018-06-01

Annual coral bleaching events, which are predicted to occur as early as the next decade in the Florida Keys, are expected to cause catastrophic coral mortality. Despite this, there is little field data on how Caribbean coral communities respond to annual thermal stress events. At Cheeca Rocks, an inshore patch reef near Islamorada, FL, the condition of 4234 coral colonies was followed over 2 yr of subsequent bleaching in 2014 and 2015, the two hottest summers on record for the Florida Keys. In 2014, this site experienced 7.7 degree heating weeks (DHW) and as a result 38.0% of corals bleached and an additional 36.6% were pale or partially bleached. In situ temperatures in summer of 2015 were even warmer, with the site experiencing 9.5 DHW. Despite the increased thermal stress in 2015, only 12.1% of corals were bleached in 2015, which was 3.1 times less than 2014. Partial mortality dropped from 17.6% of surveyed corals to 4.3% between 2014 and 2015, and total colony mortality declined from 3.4 to 1.9% between years. Total colony mortality was low over both years of coral bleaching with 94.7% of colonies surviving from 2014 to 2016. The reduction in bleaching severity and coral mortality associated with a second stronger thermal anomaly provides evidence that the response of Caribbean coral communities to annual bleaching is not strictly temperature dose dependent and that acclimatization responses may be possible even with short recovery periods. Whether the results from Cheeca Rocks represent an aberration or a true resilience potential is the subject of ongoing research.

Ecological Forecasting of West Nile Virus Outbreaks in a High-Risk Area of the North-Central United States

NASA Astrophysics Data System (ADS)

Wimberly, M. C.; Merkord, C. L.; Kightlinger, L.; Vincent, G.; Hildreth, M. B.

2015-12-01

West Nile virus (WNV) is the most widespread and important mosquito-borne pathogen in North America. Since its emergence in the western hemisphere in 1999, human WNV disease has continued to exhibit recurrent outbreaks. Perplexingly, the incidence of this tropical disease has been highest in the cold-temperate climates of the Northern Great Plains (NGP). The spatial and temporal distributions of the vector mosquitoes and bird hosts, and consequently the risk of disease in humans, are strongly influenced by temperature, precipitation, vegetation, soils, and land use. We have utilized satellite remote sensing to map these environmental factors through time and develop models of disease risk. Outbreak years in South Dakota were preceded by warm winters, and WNV cases were most likely to occur during the hottest weeks of summer. Hot spots of persistent WNV transmission within the state were associated with rural land cover as well as patterns of physiography and climate. These models are currently being integrated into the South Dakota Mosquito Early Warning system (SDMIS), an automated WNV outbreak detection system that integrates remotely-sensed environmental indicators with vector abundance and infection data from a statewide mosquito surveillance network. The major goal of this effort is to leverage global environmental monitoring datasets to provide up-to-date, locally relevant information that can improve the effectiveness of mosquito control and disease prevention activities. This system was implemented for the first time during the summer of 2015. We will review the outcomes of this implementation, including the underlying influences of temperature on WNV risk, a preliminary statewide WNV risk map, and dynamic risk predictions made during the 2015 WNV season. Lessons learned as well as plans for future years will be discussed.

Big Data Approaches To Coral-Microbe Symbiosis

NASA Astrophysics Data System (ADS)

Zaneveld, J.; Pollock, F. J.; McMinds, R.; Smith, S.; Payet, J.; Hanna, B.; Welsh, R.; Foster, A.; Ohdera, A.; Shantz, A. A.; Burkepile, D. E.; Maynard, J. A.; Medina, M.; Vega Thurber, R.

2016-02-01

Coral reefs face increasing challenges worldwide, threatened by overfishing and nutrient pollution, which drive growth of algal competitors of corals, and periods of extreme temperature, which drive mass coral bleaching. I will discuss two projects that examine how coral's complex relationships with microorganisms affect the response of coral colonies and coral species to environmental challenge. Microbiological studies have documented key roles for coral's microbial symbionts in energy harvest and defense against pathogens. However, the evolutionary history of corals and their microbes is little studied. As part of the Global Coral Microbiome Project, we are characterizing bacterial, archaeal, fungal, and Symbiodinium diversity across >1400 DNA samples from all major groups of corals, collected from 15 locations worldwide. This collection will allow us to ask how coral- microbe associations evolved over evolutionary time, and to determine whether microbial symbiosis helps predict the relative vulnerability of certain coral species to environmental stress. In the second project, we experimentally characterized how the long-term effects of human impacts such as overfishing and nutrient pollution influence coral-microbe symbiosis. We conducted a three-year field experiment in the Florida Keys applying nutrient pollution or simulated overfishing to reef plots, and traced the effects on reef communities, coral microbiomes, and coral health. The results show that extremes of temperature and algal competition destabilize coral microbiomes, increasing pathogen blooms, coral disease, and coral death. Surprisingly, these local stressors interacted strongly with thermal stress: the greatest microbiome disruption, and >80% of coral mortality happened in the hottest periods. Thus, overfishing and nutrient pollution may interact with increased climate-driven episodes of sub-bleaching thermal stress to increase coral mortality by disrupt reef communities down to microbial scales.

Nocturnal behavior by a diurnal ape, the West African chimpanzee (Pan troglodytes verus), in a savanna environment at Fongoli, Senegal.

PubMed

Pruetz, Jill D

2018-02-08

I report on the nocturnal behavior of Fongoli chimpanzees in a savanna mosaic during different seasons and lunar phases and test the hypothesis that hot daytime temperatures influence activity at night. I predicted that apes would be more active at night during periods of greater lunar illuminosity given diurnal primates' lack of visual specializations for low-light conditions and in dry season months when water scarcity exacerbated heat stress. I observed chimpanzees for 403 hrs on 40 nights between 2007 and 2013 and categorized their activity as social, movement, or vocalization. I scored their activity as occurring after moonrise or before moonset and considered the influence of moon phase (fuller versus darker phases) as well as season on chimpanzee nocturnal behavior in the analyses. Results indicate that apes were more active after moonrise or before moonset during fuller moon phases in the dry season but not the wet season. Most night-time activity involved movement (travel or forage), followed by social behavior, and long-distance vocal communication. Animals in highly seasonal habitats often exhibit thermoregulatory adaptations but, like other primates, chimpanzees lack physiological mechanisms to combat thermal stress. This study provides evidence that they may exhibit behaviors that allow them to avoid high temperatures in a savanna environment, such as feeding and socializing at night during the hottest time of year and in the brightest moon phases. The results support theories invoking thermal stress as a selective pressure for hominins in open environments where heat would constrain temporal foraging niches, and suggest an adaptability of sleeping patterns in response to external factors. © 2018 Wiley Periodicals, Inc.

Dominance-diversity relationships in ant communities differ with invasion.

PubMed

Arnan, Xavier; Andersen, Alan N; Gibb, Heloise; Parr, Catherine L; Sanders, Nathan J; Dunn, Robert R; Angulo, Elena; Baccaro, Fabricio B; Bishop, Tom R; Boulay, Raphaël; Castracani, Cristina; Cerdá, Xim; Toro, Israel Del; Delsinne, Thibaut; Donoso, David A; Elten, Emilie K; Fayle, Tom M; Fitzpatrick, Matthew C; Gómez, Crisanto; Grasso, Donato A; Grossman, Blair F; Guénard, Benoit; Gunawardene, Nihara; Heterick, Brian; Hoffmann, Benjamin D; Janda, Milan; Jenkins, Clinton N; Klimes, Petr; Lach, Lori; Laeger, Thomas; Leponce, Maurice; Lucky, Andrea; Majer, Jonathan; Menke, Sean; Mezger, Dirk; Mori, Alessandra; Moses, Jimmy; Munyai, Thinandavha Caswell; Paknia, Omid; Pfeiffer, Martin; Philpott, Stacy M; Souza, Jorge L P; Tista, Melanie; Vasconcelos, Heraldo L; Retana, Javier

2018-05-30

The relationship between levels of dominance and species richness is highly contentious, especially in ant communities. The dominance-impoverishment rule states that high levels of dominance only occur in species-poor communities, but there appear to be many cases of high levels of dominance in highly diverse communities. The extent to which dominant species limit local richness through competitive exclusion remains unclear, but such exclusion appears more apparent for non-native rather than native dominant species. Here we perform the first global analysis of the relationship between behavioral dominance and species richness. We used data from 1,293 local assemblages of ground-dwelling ants distributed across five continents to document the generality of the dominance-impoverishment rule, and to identify the biotic and abiotic conditions under which it does and does not apply. We found that the behavioral dominance-diversity relationship varies greatly, and depends on whether dominant species are native or non-native, whether dominance is considered as occurrence or relative abundance, and on variation in mean annual temperature. There were declines in diversity with increasing dominance in invaded communities, but diversity increased with increasing dominance in native communities. These patterns occur along the global temperature gradient. However, positive and negative relationships are strongest in the hottest sites. We also found that climate regulates the degree of behavioral dominance, but differently from how it shapes species richness. Our findings imply that, despite strong competitive interactions among ants, competitive exclusion is not a major driver of local richness in native ant communities. Although the dominance-impoverishment rule applies to invaded communities, we propose an alternative dominance-diversification rule for native communities. © 2018 John Wiley & Sons Ltd.

The atmospheres of earthlike planets after giant impact events

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

Lupu, R. E.; Freedman, Richard; Zahnle, Kevin

2014-03-20

It is now understood that the accretion of terrestrial planets naturally involves giant collisions, the moon-forming impact being a well-known example. In the aftermath of such collisions, the surface of the surviving planet is very hot and potentially detectable. Here we explore the atmospheric chemistry, photochemistry, and spectral signatures of post-giant-impact terrestrial planets enveloped by thick atmospheres consisting predominantly of CO{sub 2} and H{sub 2}O. The atmospheric chemistry and structure are computed self-consistently for atmospheres in equilibrium with hot surfaces with composition reflecting either the bulk silicate Earth (which includes the crust, mantle, atmosphere, and oceans) or Earth's continental crust.more » We account for all major molecular and atomic opacity sources including collision-induced absorption. We find that these atmospheres are dominated by H{sub 2}O and CO{sub 2}, while the formation of CH{sub 4} and NH{sub 3} is quenched because of short dynamical timescales. Other important constituents are HF, HCl, NaCl, and SO{sub 2}. These are apparent in the emerging spectra and can be indicative that an impact has occurred. The use of comprehensive opacities results in spectra that are a factor of two lower brightness temperature in the spectral windows than predicted by previous models. The estimated luminosities show that the hottest post-giant-impact planets will be detectable with near-infrared coronagraphs on the planned 30 m class telescopes. The 1-4 μm will be most favorable for such detections, offering bright features and better contrast between the planet and a potential debris disk. We derive cooling timescales on the order of 10{sup 5-6} yr on the basis of the modeled effective temperatures. This leads to the possibility of discovering tens of such planets in future surveys.« less

Creation of an Enhanced Geothermal System through Hydraulic and Thermal Stimulation

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

Rose, Peter Eugene

2013-04-15

This report describes a 10-year DOE-funded project to design, characterize and create an Engineered Geothermal System (EGS) through a combination of hydraulic, thermal and chemical stimulation techniques. Volume 1 describes a four-year Phase 1 campaign, which focused on the east compartment of the Coso geothermal field. It includes a description of the geomechanical, geophysical, hydraulic, and geochemical studies that were conducted to characterize the reservoir in anticipation of the hydraulic stimulation experiment. Phase 1 ended prematurely when the drill bit intersected a very permeable fault zone during the redrilling of target stimulation well 34-9RD2. A hydraulic stimulation was inadvertently achieved,more » however, since the flow of drill mud from the well into the formation created an earthquake swarm near the wellbore that was recorded, located, analyzed and interpreted by project seismologists. Upon completion of Phase 1, the project shifted focus to a new target well, which was located within the southwest compartment of the Coso geothermal field. Volume 2 describes the Phase 2 studies on the geomechanical, geophysical, hydraulic, and geochemical aspects of the reservoir in and around target-stimulation well 46A-19RD, which is the deepest and hottest well ever drilled at Coso. Its total measured depth exceeding 12,000 ft. It spite of its great depth, this well is largely impermeable below a depth of about 9,000 ft, thus providing an excellent target for stimulation. In order to prepare 46A-19RD for stimulation, however, it was necessary to pull the slotted liner. This proved to be unachievable under the budget allocated by the Coso Operating Company partners, and this aspect of the project was abandoned, ending the program at Coso. The program then shifted to the EGS project at Desert Peak, which had a goal similar to the one at Coso of creating an EGS on the periphery of an existing geothermal reservoir. Volume 3 describes the activities that the Coso team contributed to the Desert Peak project, focusing largely on a geomechanical investigation of the Desert Peak reservoir, tracer testing between injectors 21-2 and 22-22 and the field's main producers, and the chemical stimulation of target well 27-15.« less

Creation of an Enhanced Geothermal System through Hydraulic and Thermal Stimulation

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

Rose, Peter Eugene

This report describes a 10-year DOE-funded project to design, characterize and create an Engineered Geothermal System (EGS) through a combination of hydraulic, thermal and chemical stimulation techniques. Volume 1 describes a four-year Phase 1 campaign, which focused on the east compartment of the Coso geothermal field. It includes a description of the geomechanical, geophysical, hydraulic, and geochemical studies that were conducted to characterize the reservoir in anticipation of the hydraulic stimulation experiment. Phase 1 ended prematurely when the drill bit intersected a very permeable fault zone during the redrilling of target stimulation well 34-9RD2. A hydraulic stimulation was inadvertently achieved,more » however, since the flow of drill mud from the well into the formation created an earthquake swarm near the wellbore that was recorded, located, analyzed and interpreted by project seismologists. Upon completion of Phase 1, the project shifted focus to a new target well, which was located within the southwest compartment of the Coso geothermal field. Volume 2 describes the Phase 2 studies on the geomechanical, geophysical, hydraulic, and geochemical aspects of the reservoir in and around target-stimulation well 46A-19RD, which is the deepest and hottest well ever drilled at Coso. Its total measured depth exceeding 12,000 ft. It spite of its great depth, this well is largely impermeable below a depth of about 9,000 ft, thus providing an excellent target for stimulation. In order to prepare 46A-19RD for stimulation, however, it was necessary to pull the slotted liner. This proved to be unachievable under the budget allocated by the Coso Operating Company partners, and this aspect of the project was abandoned, ending the program at Coso. The program then shifted to the EGS project at Desert Peak, which had a goal similar to the one at Coso of creating an EGS on the periphery of an existing geothermal reservoir. Volume 3 describes the activities that the Coso team contributed to the Desert Peak project, focusing largely on a geomechanical investigation of the Desert Peak reservoir, tracer testing between injectors 21-2 and 22-22 and the field's main producers, and the chemical stimulation of target well 27-15.« less

Controlled metal-semiconductor sintering/alloying by one-directional reverse illumination

DOEpatents

Sopori, Bhushan L.

1993-01-01

Metal strips deposited on a top surface of a semiconductor substrate are sintered at one temperature simultaneously with alloying a metal layer on the bottom surface at a second, higher temperature. This simultaneous sintering of metal strips and alloying a metal layer on opposite surfaces of the substrate at different temperatures is accomplished by directing infrared radiation through the top surface to the interface of the bottom surface with the metal layer where the radiation is absorbed to create a primary hot zone with a temperature high enough to melt and alloy the metal layer with the bottom surface of the substrate. Secondary heat effects, including heat conducted through the substrate from the primary hot zone and heat created by infrared radiation reflected from the metal layer to the metal strips, as well as heat created from some primary absorption by the metal strips, combine to create secondary hot zones at the interfaces of the metal strips with the top surface of the substrate. These secondary hot zones are not as hot as the primary hot zone, but they are hot enough to sinter the metal strips to the substrate.

Microclimatic effects of planted hydroponic structures in urban environment: measurements and simulations

NASA Astrophysics Data System (ADS)

Katsoulas, N.; Antoniadis, D.; Tsirogiannis, I. L.; Labraki, E.; Bartzanas, T.; Kittas, C.

2017-05-01

The objectives of this effort was to study the effect of vertical (green wall) and horizontal (pergola) green structures on the microclimate conditions of the building surroundings and estimate the thermal perception and heat stress conditions near the two structures. The experimental data were used to validate the results simulated by the recent version (V4.0 preview III) of ENVI-met software which was used to simulate the effect of different design parameters of a pergola and a green façade on microclimate and heat stress conditions. Further aim is to use these results for better design of green structures. The microclimate measurements were carried out in real scale structures (hydroponic pergola and hydroponic green wall) at the Kostakii Campus of the Technological Education Institute of Epirus (Arta, Greece). The validation results showed a very good agreement between measured and simulated values of air temperature, with Tair,sim = 0.98 Tair,meas in the Empty atrium and Tair,sim = 0.99 Tair,meas in the Atrium with pergola, with a determination coefficient R 2 of 0.98 and 0.93, respectively. The model was used to predict the effects of green structures on air temperature (Tair), relative humidity (RH), and mean radiant temperature (Tmrt). The output values of these parameters were used as input data in the RayMan pro (V 2.1) model for estimating the physiologically equivalent temperature (PET) of different case scenarios. The average daytime value of simulated air temperature in the atrium for the case without and with pergola during three different days was 29.2 and 28.9 °C while the corresponding measured values were 29.7 and 29.2 °C. The results showed that compared to the case with no pergola in the atrium, covering 100% the atrium area with a planted pergola reduced at the hottest part of the day Tmrt and PET values by 29.4 and 17.9 °C, respectively. Although the values of air temperature (measured and simulated) were not greatly affected by the presence of a green wall, the most important effect of green wall to the building wall is the reduction of solar radiation behind the green wall. This reduction leads to a significant reduction (about 8 °C) of building surface temperature behind the green wall and accordingly to a reduction of the energy load of the building.

Artist Impression of Hot

NASA Image and Video Library

2015-12-14

This image shows an artist's impression of the 10 hot Jupiter exoplanets studied using the Hubble and Spitzer space telescopes. From top left to lower left, these planets are WASP-12b, WASP-6b, WASP-31b, WASP-39b, HD 189733b, HAT-P-12b, WASP-17b, WASP-19b, HAT-P-1b and HD 209458b. The colors of the planets are for illustration purposes only. There is little scientific data on color with the exception of HD 189733b, which became known as the "blue planet." The planets are also depicted with a variety of different cloud properties. The wind patterns shown on these 10 planets, which resemble the visible structures on Jupiter, are based on theoretical models. The illustrations are to scale with each other. HAT-P-12b, the smallest of these planets, is approximately the size of Jupiter, while WASP-17b, the largest one in the sample, is almost twice the size. The hottest planets within the sample are portrayed with a glowing night side. This effect is strongest on WASP-12b, the hottest exoplanet in the sample, but also visible on WASP-19b and WASP-17b. It is also known that several of the planets exhibit strong Rayleigh scattering. This effect causes the blue hue of the daytime sky and the reddening of the sun at sunset on Earth. It is also visible as a blue edge on the planets WASP-6b, HD 189733b, HAT-P-12b and HD 209458b. http://photojournal.jpl.nasa.gov/catalog/PIA20056

Artificial insemination of Holstein heifers with sex-sorted semen during the hot season in a subtropical region.

PubMed

Chang, Lian-Ben; Chou, Chih-Jen; Shiu, Jia-Shian; Tu, Po-An; Gao, Shi-Xuan; Peng, Shao-Yu; Wu, Shinn-Chih

2017-08-01

Our aim was to investigate insemination techniques in order to improve pregnancy rates of artificial insemination (AI) using sex-sorted semen (sexed AI) in cattle in tropical and subtropical (T/ST) regions. In T/ST regions, the pregnancy rates by sexed AI are reportedly the lowest in the hottest months of the year, with less than 15% in cows and 35-40% in heifers (PMID 24048822). We compared sexed AI by depositing the semen into the uterine body (UB-AI, n = 12) versus the unilateral uterine horn (UUH-AI, n = 14) of pre-ovulation heifers. The ovary and follicle were assessed by rectal ultrasound before AI. After insemination, pregnancy was determined by ultrasound at approximately 40 days and approximately 70 days. In the present study, we demonstrated that high pregnancy rates (>70%) by sexed AI in the hottest season in a subtropical region such as Taiwan can be achieved when heifers with pre-ovulation follicles are used. The overall pregnancy rates were 54% higher in the UUH-AI (71%) group than in the UB-AI (42%) group (P = 0.06), examined on approximately 40 days post-sexed AI. Surprisingly, however, the pregnancy outcome appeared to be higher in the hot season (62%) than in the cool season (46%) although this difference was not statistically significant. Based on the present study, we recommend that cattle breeders perform UUH-AI using sex-sorted semen for heifers with pre-ovulation follicles in order to achieve satisfactory pregnancy outcome in the hot seasons in T/ST regions.

PARTICLE ACCELERATOR AND METHOD OF CONTROLLING THE TEMPERATURE THEREOF

DOEpatents

Neal, R.B.; Gallagher, W.J.

1960-10-11

A method and means for controlling the temperature of a particle accelerator and more particularly to the maintenance of a constant and uniform temperature throughout a particle accelerator is offered. The novel feature of the invention resides in the provision of two individual heating applications to the accelerator structure. The first heating application provided is substantially a duplication of the accelerator heat created from energization, this first application being employed only when the accelerator is de-energized thereby maintaining the accelerator temperature constant with regard to time whether the accelerator is energized or not. The second heating application provided is designed to add to either the first application or energization heat in a manner to create the same uniform temperature throughout all portions of the accelerator.

The Hottest Hot Jupiters May Host Atmospheric Dynamos

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

Rogers, T. M.; McElwaine, J. N.

2017-06-01

Hot Jupiters have proven themselves to be a rich class of exoplanets that test our theories of planetary evolution and atmospheric dynamics under extreme conditions. Here, we present three-dimensional magnetohydrodynamic simulations and analytic results that demonstrate that a dynamo can be maintained in the thin, stably stratified atmosphere of a hot Jupiter, independent of the presumed deep-seated dynamo. This dynamo is maintained by conductivity variations arising from strong asymmetric heating from the planets’ host star. The presence of a dynamo significantly increases the surface magnetic field strength and alters the overall planetary magnetic field geometry, possibly affecting star–planet magnetic interactions.

Colored knot polynomials for arbitrary pretzel knots and links

DOE PAGES

Galakhov, D.; Melnikov, D.; Mironov, A.; ...

2015-04-01

A very simple expression is conjectured for arbitrary colored Jones and HOMFLY polynomials of a rich (g+1)-parametric family of pretzel knots and links. The answer for the Jones and HOMFLY is fully and explicitly expressed through the Racah matrix of Uq(SU N), and looks related to a modular transformation of toric conformal block. Knot polynomials are among the hottest topics in modern theory. They are supposed to summarize nicely representation theory of quantum algebras and modular properties of conformal blocks. The result reported in the present letter, provides a spectacular illustration and support to this general expectation.

Introduction to Semiconductor Devices

NASA Astrophysics Data System (ADS)

Brennan, Kevin F.

2005-03-01

This volume offers a solid foundation for understanding the most important devices used in the hottest areas of electronic engineering today, from semiconductor fundamentals to state-of-the-art semiconductor devices in the telecommunications and computing industries. Kevin Brennan describes future approaches to computing hardware and RF power amplifiers, and explains how emerging trends and system demands of computing and telecommunications systems influence the choice, design and operation of semiconductor devices. In addition, he covers MODFETs and MOSFETs, short channel effects, and the challenges faced by continuing miniaturization. His book is both an excellent senior/graduate text and a valuable reference for practicing engineers and researchers.

Spectral Analysis of the O(He)-Type Central Stars of the Planetary Nebulae K 1-27 and LoTr 4

NASA Technical Reports Server (NTRS)

Reindl, N.; Ringat, E.; Rauch, T.; Werner, K.; Kruk, J. W.

2011-01-01

The four known O(He) stars are the only amongst the hottest post-AGB stars whose atmospheres are composed of almost pure helium. Thus, their evolution deviates from the hydrogen-defiCient post-AGB evolutionary sequence of carbon-dominated stars like e.g. PG 1159 stars. The origin of the O(He) stars is still not explained. They might be either post-early AGB stars or the progeny of R Coronae Borealis stars. We present preliminary results of a non-LTE spectral analysis based on FUSE and HST/COS observations.

The evolution of the lithium abundances of solar-type stars. II - The Ursa Major Group

NASA Technical Reports Server (NTRS)

Soderblom, David R.; Pilachowski, Catherine A.; Fedele, Stephen B.; Jones, Burton F.

1993-01-01

We draw upon a recent study of the membership of the Ursa Major Group (UMaG) to examine lithium among 0.3 Gyr old solar-type stars. For most G and K dwarfs, Li confirms the conclusions about membership in UMaG reached on the basis of kinematics and chromospheric activity. G and K dwarfs in UMaG have less Li than comparable stars in the Pleiades. This indicates that G and K dwarfs undergo Li depletion while they are on the main sequence, in addition to any pre-main-sequence depletion they may have experienced. Moreover, the Li abundances of the Pleiades K dwarfs cannot be attributed to main-sequence depletion alone, demonstrating that pre-main-sequence depletion of Li also takes place. The sun's Li abundance implies that the main-sequence mechanism becomes less effective with age. The hottest stars in UMaG have Li abundances like those of hot stars in the Pleiades and Hyades and in T Tauris, and the two genuine UMaG members with temperatures near Boesgaard's Li chasm have Li abundances consistent with that chasm developing fully by 0.3 Gyr for stars with UMaG's metallicity. We see differences in the abundance of Li between UMaG members of the same spectral types, indicating that a real spread in the lithium abundance exists within this group.

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

Boussaa, S. Anas, E-mail: sabiha.anas@gmail.com; Kheloufi, A.; Kefaifi, A.

Raw materials are essential for the functioning of modern societies, and access to these raw materials is vital to the world economy. Sustainable development, both globally level, raises important new challenges associated with access and efficient use of raw materials. High purity quartz, is consider as a critical raw material and it is a rare commodity that only forms under geological conditions where a narrow set of chemical and physical parameters is fulfilled. When identified and following special beneficiation techniques, high purity quartz obtains very attractive prices and is applied in high technology sectors that currently are under rapid expansionmore » such as photovoltaic solar cells, silicon metal - oxide wafers in the semiconductor industry and long distance optical fibers that are used in communication networks. Crystalline silicon remains the principal material for photovoltaic technology. Metallurgical silicon is produced industrially by the reduction of silica with carbon in an electric arc furnace at temperatures higher than 2000 °C in the hottest parts, by a reaction that can be written ideally as: SiO{sub 2} + 2C = Si + 2CO. The aim of this study has been to test experimental methods for investigating the various physical and chemical proprieties of Hoggar quartz with different techniques: X Ray Fluorescence, infra-red spectroscopy, Scanning Electron Microscopy, Optic Microscopy, Carbon Analyzer and Vickers Hardness. The results show finally that the quartz has got good result in purity but need enrichment for the photovoltaic application.« less

Exploring new classification criteria for the earliest type stars: the 3400 Aregion

NASA Astrophysics Data System (ADS)

Morrell, Nidia I.; Walborn, Nolan R.; Arias, Julia I.

2002-02-01

We propose spectroscopic observations of a sample of standard O2-O4 stars in the wavelength region containing the N IV 3479-83-85 Aand O IV 3381-85-3412 Alines, in order to analyze the behavior of these spectral features as a function of the spectral type. We aim to define new classification criteria for the hottest stars, evaluating these N IV and O IV lines near 3400 Aas possible temperature and luminosity discriminators. The former spectral class O3 has just been split into three different classes: O2, O3 and O3.5 (Walborn et al. 2001). The paucity of classification criteria at these types in the traditional wavelength domain (4000 - 4700 Å), makes clear the need to explore other spectral ranges in order to define additional constraints on the determination of spectral types and luminosity classes. The wavelength range around 3400 Ahas been observed in many faint, crowded early O-type stars by HST/FOS, the corresponding data being available from the HST archive. This enhances our interest in observing this spectral range in the classification standards for the early O-type stars in order to make these existing HST observations even more useful, allowing the determination of accurate spectral types for unknown objects from them, once the behavior of the new criteria in the standards has been charted.

Global X-ray Spectral Variation of Eta Carinae through the 2003 X-ray Minimum

NASA Technical Reports Server (NTRS)

Hamaguchi, K.; Corcoran, M. F.; White, N. E.; Gull, T.; Damineli, A.; Davidson, K.

2006-01-01

We report on the results of the X-ray observing campaign of the massive, evolved star Eta Carinae in 2003 around its recent X-ray Minimum, mainly using data from the XMM-Newton observatory. These imaging observations show that the hard X-ray source associated with the Eta Carinae system does not completely disappear in any of the observations during the Minimum. The variation of the spectral shape revealed two emission components. One newly discovered component did not exhibit any variation on kilo-second to year-long timescales, in a combined analysis with earlier ASCA and ROSAT data, and might represent the collision of a high speed outflow from Eta Carinae with ambient gas clouds. The other emission component was strongly variable in flux but the temperature of the hottest plasma did not vary significantly at any orbital phase. Absorption to the hard emission, was about a factor of three larger than the absorption determined from the cutoff of the soft emission, and reached a maximum of approx.4 x 10(exp 23)/sq cm before the Minimum. The thermal Fe\\rm XXV emission line showed significant excesses on both the red and blue sides of the line outside the Minimum and exhibited a large redward excess during the Minimum. This variation in the line profile probably requires an abrupt change in ionization balance in the shocked gas.

Dynamics of the Shocked Gas in the Eta Carinae System as Seen by Chandra

NASA Technical Reports Server (NTRS)

Corcoran, M. F.; Hamaguchi, K.; Henley, D. B.; Ishibashi, K.; Gull, T.; Nielsen, K.; Pittard, J. M.

2006-01-01

We report on a series of X-ray spectra of the supermassive star Eta Carinae obtained by the High Energy Transmission Grating Spectrometer on the CHANDRA X-ray observatory before, during and after the star's X-ray minimum in the summer of 2003. The X-ray spectra show significant variations in emission measure and absorption, in the strength of the iron K edge and fluorescent iron emission, but show little change in the distribution of emission measure with temperature. The CHANDRA spectra also resolve emission from Si, S, Fe and other elements in H-like and He-like configurations. The HETGS spectra show that these lines change in centroid energy along with evidence of changes in the forbidden-to-intercombination ratios of the He-like triplets. These spectra offer strong support that the X-ray emission originates within a shock cone around an unseen, massive companion. The variations of the X-ray line spectrum provide a direct measure of the dynamics of the shocked gas in this cone and also evidence that the hottest region of the shock is not always in collisional ionization equilibrium. We discuss these results in light of the recent discovery of He II 4686 emission and the reported discovery of FUV emission from the companion star. This work was supported by SAO/Chandra grant GO3-4008A.

An equation for pressure of a two-dimensional Yukawa liquid

NASA Astrophysics Data System (ADS)

Feng, Yan; Li, Wei; Wang, Qiaoling; Lin, Wei; Goree, John; Liu, Bin

2016-10-01

Thermodynamic behavior of two-dimensional (2D) dusty plasmas has been studied experimentally and theoretically recently. As a crucial parameter in thermodynamics, the pressure of dusty plasmas arises from frequent collisions of individual dust particles. Here, equilibrium molecular dynamical simulations were performed to study the pressure of 2D Yukawa liquids. A simple analytical expression for the pressure of a 2D Yukawa liquid is found by fitting the obtained pressure data over a wide range of temperatures, from the coldest close to the melting point, to the hottest about 70 times higher than the melting points. The obtained expression verifies that the pressure can be written as the sum of a potential term which is a simple multiple of the Coulomb potential energy at a distance of Wigner-Seitz radius, and a kinetic term which is a multiple of the one for an ideal gas. Dimensionless coefficients for each of these terms are found empirically, by fitting. The resulting analytical expression, with its empirically determined coefficients, is plotted as isochors, or curves of constant area. These results should be applicable to 2D dusty plasmas. Work in China supported by by the National Natural Science Foundation of China under Grant No. 11505124, the 1000 Youth Talents Plan, and startup funds from Soochow University. Work in the US supported by DOE & NSF.

Naga chilli: a potential source of capsaicinoids with broad-spectrum ethnopharmacological applications.

PubMed

Meghvansi, M K; Siddiqui, S; Khan, Md Haneef; Gupta, V K; Vairale, M G; Gogoi, H K; Singh, Lokendra

2010-10-28

Capsicum species are not only cultivated as vegetable and condiment crops but are also incorporated into a number of medicinal preparations in the ancient literature around the world. 'Naga chilli' or 'Bhoot Jolokia' (Capsicum chinense Jacq.) is a chilli variety indigenous to the northeast region of India and has been recognized as the hottest chilli in the world. It has also been used conventionally in treating various human ailments since time immemorial by the indigenous people of the northeast India. Despite being an important crop of the northeast India, the information on the biology and cultivation of Naga chilli is very scanty and scattered. The present article reviews the scientific literature on above aspects with particular emphasis on identifying the key regional issues which need to be addressed urgently by the policy makers in order to harness its potential as an important source of capsaicinoids. Further, an attempt has been made to collate the potential of capsaicinoids in various ethnopharmacological applications such as pain therapy, body temperature regulation, anti-obesity treatments, anticancer therapy and as antioxidant and antimicrobial agent. We anticipate that this literature analysis of traditional medicinal uses and experimental trials of Capsicum using modern scientific approaches shall provide a basis for suggesting important areas where sincere research efforts are warranted to bridge the gap between traditional medicinal knowledge and modern biomedical knowledge. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

Study of a Solar X-Ray Telescope

NASA Technical Reports Server (NTRS)

Golub, Leon

1997-01-01

The highly structured nature of the outer solar atmosphere seems to be intimately linked to the presence, at the solar surface, of magnetic fields that have been generated inside the Sun and have emerged to the surface. The corona is brightest (and also hottest) at just those locations where the magnetic field has emerged from inside the Sun. Dynamo theory predicts that strong magnetic fields will be generated deep in the solar interior and that bundles or 'ropes' of magnetic flux will float to the surface. When this happens, a magnetically bipolar region will become visible, extending above the surface in a three-dimensional structure. The field lines penetrate through the surface, showing two magnetic poles, and also exhibit a three-dimensional structure above the surface. The structure created by the field emergence is rooted in the (relatively) cool photosphere and extends through the chromosphere and transition region to the corona. Thus, the magnetic field creates a region, called an active region, which contains portions at temperatures from less than 10(exp 4) K to greater than 10(exp 6) K, and is therefore visible at wavelengths from the infrared through x-rays. The locations where the magnetic field leaves and reenters the visible surface are called the 'footpoints' of the coronal structures associated with the magnetic field. The magnetic fields themselves are not directly visible. However, the hot coronal plasma is, for the most part, constrained to follow the direction of the magnetic field lines in the atmosphere. Now, 100 years after the discovery of x-rays by Wilhelm Roentgen in 1896, we can routinely make observations of the solar corona from outside the Earth's atmosphere in this region of the electromagnetic spectrum. As shown by comparing x-ray images with magnetograms, the bright corona over these bipolar magnetic regions consists of closed structures that seem to follow the orientation of the magnetic field. Although we can see down to the photosphere at x-ray wavelengths when observing the disk of the Sun, this part of the solar atmosphere emits so little that far from the peak of its Planck curve it appears dark in x-ray images. This impression of hot plasma following the magnetic field direction is further strengthened by quantitative studies that calculate coronal magnetic field strength and direction based on photospheric measurements and compare them with the observed brightness and location of the x-ray emitting structures. Such comparisons make it clear that, for the most part, the hot plasma conforms to the geometry of the magnetic field and that the coronal brightness is strongly linked to the strength of the magnetic fields which have erupted to the solar surface from the interior. It is also the case that the larger-scale, fainter corona, as well as coronal holes, are strongly influenced by the large-scale solar magnetic field. We may get a small hint of the reason that the coronal plasma outlines the direction of B by examining the thermal conductivity of a hot plasma in the presence of a magnetic field. This quantity has enormously different values in the directions parallel and perpendicular to the field for a coronal temperature of 10(exp 6) K, a particle density of 10(exp 9)/cu cm and a magnetic field strength of 100 G, the conductivity along the field is approximately 13 orders of magnitude greater than that perpendicular to the field. It is therefore not surprising that a parcel of plasma which is locally heated would conduct that heat preferentially in the direction of the field. We also note that the thermal conductivity parallel to the magnetic field increases with temperature T, while the perpendicular conductivity decreases. To the extent that the loop aspect ratio, i.e., the ratio of loop length to loop width, is determined by the thermal conductivity, we would expect that higher temperature loops are longer and thinner than cooler ones. However, if the loop width becomes smaller than the spatial resolution of the observing instrument, this effect will not be directly observable. For organizational purposes, we provide a listing of some scientific objectives for a Solar-B x-ray telescope, arranged in terms of identifiable features in the corona.

Dislocation loop formation by swift heavy ion irradiation of metals.

PubMed

Khara, Galvin S; Murphy, Samuel T; Duffy, Dorothy M

2017-07-19

A coupled two-temperature, molecular dynamics methodology is used to simulate the structural evolution of bcc metals (Fe and W) and fcc metals (Cu and Ni) following irradiation by swift heavy ions. Electronic temperature dependent electronic specific heat capacities and electron-phonon coupling strengths are used to capture the full effects of the variation in the electronic density of states. Tungsten is found to be significantly more resistant to damage than iron, due both to the higher melting temperature and the higher thermal conductivity. Very interesting defect structures, quite different from defects formed in cascades, are found to be created by swift heavy ion irradiation in the bcc metals. Isolated vacancies form a halo around elongated interstitial dislocation loops that are oriented along the ion path. Such configurations are formed by rapid recrystallization of the molten cylindrical region that is created by the energetic ion. Vacancies are created at the recrystallization front, resulting in excess atoms at the core which form interstitial dislocation loops on completion of crystallization. These unique defect structures could, potentially, be used to create metal films with superior mechanical properties and interesting nanostructures.

Dislocation loop formation by swift heavy ion irradiation of metals

NASA Astrophysics Data System (ADS)

Khara, Galvin S.; Murphy, Samuel T.; Duffy, Dorothy M.

2017-07-01

A coupled two-temperature, molecular dynamics methodology is used to simulate the structural evolution of bcc metals (Fe and W) and fcc metals (Cu and Ni) following irradiation by swift heavy ions. Electronic temperature dependent electronic specific heat capacities and electron-phonon coupling strengths are used to capture the full effects of the variation in the electronic density of states. Tungsten is found to be significantly more resistant to damage than iron, due both to the higher melting temperature and the higher thermal conductivity. Very interesting defect structures, quite different from defects formed in cascades, are found to be created by swift heavy ion irradiation in the bcc metals. Isolated vacancies form a halo around elongated interstitial dislocation loops that are oriented along the ion path. Such configurations are formed by rapid recrystallization of the molten cylindrical region that is created by the energetic ion. Vacancies are created at the recrystallization front, resulting in excess atoms at the core which form interstitial dislocation loops on completion of crystallization. These unique defect structures could, potentially, be used to create metal films with superior mechanical properties and interesting nanostructures.

Thermodynamic Modeling of a Solid Oxide Fuel Cell to Couple with an Existing Gas Turbine Engine Model

NASA Technical Reports Server (NTRS)

Brinson, Thomas E.; Kopasakis, George

2004-01-01

The Controls and Dynamics Technology Branch at NASA Glenn Research Center are interested in combining a solid oxide fuel cell (SOFC) to operate in conjunction with a gas turbine engine. A detailed engine model currently exists in the Matlab/Simulink environment. The idea is to incorporate a SOFC model within the turbine engine simulation and observe the hybrid system's performance. The fuel cell will be heated to its appropriate operating condition by the engine s combustor. Once the fuel cell is operating at its steady-state temperature, the gas burner will back down slowly until the engine is fully operating on the hot gases exhausted from the SOFC. The SOFC code is based on a steady-state model developed by The U.S. Department of Energy (DOE). In its current form, the DOE SOFC model exists in Microsoft Excel and uses Visual Basics to create an I-V (current-voltage) profile. For the project's application, the main issue with this model is that the gas path flow and fuel flow temperatures are used as input parameters instead of outputs. The objective is to create a SOFC model based on the DOE model that inputs the fuel cells flow rates and outputs temperature of the flow streams; therefore, creating a temperature profile as a function of fuel flow rate. This will be done by applying the First Law of Thermodynamics for a flow system to the fuel cell. Validation of this model will be done in two procedures. First, for a given flow rate the exit stream temperature will be calculated and compared to DOE SOFC temperature as a point comparison. Next, an I-V curve and temperature curve will be generated where the I-V curve will be compared with the DOE SOFC I-V curve. Matching I-V curves will suggest validation of the temperature curve because voltage is a function of temperature. Once the temperature profile is created and validated, the model will then be placed into the turbine engine simulation for system analysis.

Continuing Evolution of the Hydrothermal System at the RIDGE2000 ISS, 9-10° N EPR: 1991-2004

NASA Astrophysics Data System (ADS)

von Damm, K. L.; Parker, C. M.; Beers, K. A.; Hyde, A. A.

2004-12-01

We have been studying the evolution of the chemical composition of the mid-ocean ridge (MOR) hydrothermal system on the East Pacific Rise from 9° 46-51'N since it was impacted by volcanic eruptions in 1991/2. We have been using the chemical and temperature data to infer the processes that are occurring subseafloor in the upper oceanic crust. As of March 2004, the chemical compositions of the vent fluids from this site have not yet stabilized. This observation is helping us to better understand not only the impact of magmatic events on these systems, but also the time scales on which they occur. Centered at the RIDGE2000 ISS "bull's-eye" at 9° 50'N we have noted a striking increase in the number of hydrothermal vents as well as in their measured fluid temperatures beginning after ~2000. In November 2003 we first noted the formation of a black smoker vent at the Tica site (measured T=342° C). In March 2004 we identified another new area of robust flow near the Bio9 vents at 9° 50'N, the 'Alvinellid Mat,' that we anticipate will form an additional black smoker to the three currently active at this site. In March 2004 we measured temperatures of 388° C in fluids from both the Bio9 and Bio9' smokers, putting them essentially on the two phase curve for seawater at this depth. For all of the Bio9 vents, as well as Tica, the fluids contain less than 300 mmoles/kg of Cl, approximately half the local seawater concentration. These high temperature and low Cl concentrations are accompanied by unusually low Si concentrations, <9.5 mmoles/kg. These data suggest a relatively shallow depth of reaction for the fluids, within a few hundred meters of the seafloor. These are the hottest temperatures measured in the Bio9 vents since the eruption in 1992. In contrast, the temperatures at P vent, about 60m south have cooled by ˜15° C since 2002. About 400m south, the chlorinity of the fluids from Ty and Io vents have increased, and Tube Worm Pillar, about 400m further south has become inactive. Therefore the changes in the vent fluids vary widely and often in opposite senses, over ˜1.5km of very hydrothermally active ridge. A more complete discussion of the changes and our interpretation of their implications for processes occurring subseafloor will be presented.

State of the Climate in 2003.

NASA Astrophysics Data System (ADS)

Levinson, D. H.; Waple, A. M.

2004-06-01

The earth's climate was influenced by a moderate El Niño in the tropical Pacific Ocean at the beginning of 2003. This ENSO warm event developed during October November of 2002, and eventually dissipated during March April 2003, giving way to near-neutral ENSO conditions for the remainder of the year. Despite the cessation of El Niño during the boreal spring, the ENSO warm event affected regional precipitation anomalies over a broad area of the Pacific basin, including wet anomalies along the west coast of South America, and dry anomalies in eastern Australia, the southwest Pacific, and Hawaii.The global mean surface temperature in 2003 was within the highest three annual values observed during the period of regular instrumental records (beginning in approximately 1880), but below the 1998 record-high value. Global surface temperatures in 2003 were 0.46°C (0.83°F) above the 1961 90 mean, according to one U.K. record, which ranked as third highest in this archive. In the U.S. temperature archive, the 2003 anomaly was also 0.46°C (0.83°F), equivalent to the 2002 value, which ranked second over the period of record. Similar to the surface temperature anomalies, satellite retrievals of global midtropospheric temperatures ranked 2003 as third warmest relative to the 1979 98 mean value.The hurricane season was extremely active in the Atlantic basin, with a total of 16 tropical storms, seven hurricanes, and three major hurricanes in 2003. Five of these tropical cyclones made landfall in the United States, three made landfall in northeastern Mexico, and a tropical storm affected Hispañola. In addition, Nova Scotia and Bermuda experienced devastating impacts from hurricanes in 2003. Another notable aspect of the season in the Atlantic was the formation of five tropical storms over the Gulf of Mexico, which tied the season high observed in 1957. In addition, three tropical storms formed outside of the normal (June November) hurricane season in 2003—one in April and two in December—which made this the first season since 1887 that two tropical storms have formed during December in the Atlantic basin. Also of note was the below-normal activity in the eastern North Pacific basin. There were no major hurricanes in this basin during the 2003 season, which made this the first year since 1977 with no category 3 5 storms. Despite the below-normal activity, four tropical cyclones made landfall on the Pacific coast of Mexico, two as hurricanes and two as tropical storms, which was twice the long-term mean.The summer of 2003 was one of the warmest on record across parts of Europe, where a heat wave affected most of Central and Western Europe. Two distinct periods of exceptional heat occurred during the season—the first in June and the second during the latter half of July and the first half of August. The July August heat wave was the more serious of the two, since it coincided with the normal peak in summer temperatures and was accompanied by an almost complete absence of rainfall. The high temperatures and dry conditions exacerbated forest fires that burned across southern France and Portugal in July and August. The record heat wave spread across most of Western Europe in August, and it was likely the warmest summer since 1540 in parts of Central Europe. In France, 11,000 heat-related deaths were reported between late July and mid-August. In Germany, both June and August were the warmest such months since at least the beginning of the twentieth century. The summer was also the hottest in Germany since 1901, and, with the exception of some stations in northern and northwestern Germany, it was the hottest summer since the beginning of recorded measurements.Other climatic events of note during 2003 included 1) record wet conditions across parts of the southeast, mid-Atlantic, and eastern coast of the United States; 2) record cold temperatures and anomalous June snowfalls in European Russia; 3) 546 tornadoes during May 2003 in the United States, which was an all-time record of reported tornadoes for any month; 4) continuing drought conditions across the western United States, with some areas experiencing their fourth and fifth years of significant precipitation deficits; 5) severe bushfires in eastern Australia in January, the worst wildfire season on record in British Columbia during August, as well as severe wildfires across southern California in October; 6) above-average rainfall across West Africa and the Sahel, which had its second wettest rainy season since 1990; 7) a return to normal rainfall across the Indian subcontinent during the summer monsoon; and 8) a near-record extent of the Antarctic ozone hole, which was 28.2 million km2 at its maximum in September 2003.

Hubble Watches Star Clusters on a Collision Course

NASA Image and Video Library

2012-08-16

Image release August 16, 2012 Astronomers using data from NASA's Hubble Space Telescope have caught two clusters full of massive stars that may be in the early stages of merging. The 30 Doradus Nebula is 170,000 light-years from Earth. What at first was thought to be only one cluster in the core of the massive star-forming region 30 Doradus has been found to be a composite of two clusters that differ in age by about one million years. The entire 30 Doradus complex has been an active star-forming region for 25 million years, and it is currently unknown how much longer this region can continue creating new stars. Smaller systems that merge into larger ones could help to explain the origin of some of the largest known star clusters. The Hubble observations, made with the Wide Field Camera 3, were taken Oct. 20-27, 2009. The blue color is light from the hottest, most massive stars; the green from the glow of oxygen; and the red from fluorescing hydrogen. To read more about this image go to: www.nasa.gov/mission_pages/hubble/science/cluster-collisi... Image Credit: NASA, ESA, and E. Sabbi (ESA/STScI) NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Degradation of TBC Systems in Environments Relevant to Advanced Gas Turbines for IGCC Systems

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

Gleeson, Brian

2014-09-30

Air plasma sprayed (APS) thermal barrier coatings (TBCs) are used to provide thermal insulation for the hottest components in gas turbines. Zirconia stabilized with 7wt% yttria (7YSZ) is the most common ceramic top coat used for turbine blades. The 7YSZ coating can be degraded from the buildup of fly-ash deposits created in the power-generation process. Fly ash from an integrated gasification combined cycle (IGCC) system can result from coal-based syngas. TBCs are also exposed to harsh gas environments containing CO 2, SO 2, and steam. Degradation from the combined effects of fly ash and harsh gas atmospheres has the potentialmore » to severely limit TBC lifetimes. The main objective of this study was to use lab-scale testing to systematically elucidate the interplay between prototypical deposit chemistries (i.e., ash and its constituents, K 2SO 4, and FeS) and environmental oxidants (i.e., O 2, H 2O and CO 2) on the degradation behavior of advanced TBC systems. Several mechanisms of early TBC failure were identified, as were the specific fly-ash constituents responsible for degradation. The reactivity of MCrAlY bondcoats used in TBC systems was also investigated. The specific roles of oxide and sulfate components were assessed, together with the complex interplay between gas composition, deposit chemistry and alloy reactivity. Bondcoat composition design strategies to mitigate corrosion were established, particularly with regard to controlling phase constitution and the amount of reactive elements the bondcoat contains in order to achieve optimal corrosion resistance.« less

Electrically excited hot-electron dominated fluorescent emitters using individual Ga-doped ZnO microwires via metal quasiparticle film decoration.

PubMed

Liu, Yang; Jiang, Mingming; Zhang, Zhenzhong; Li, Binghui; Zhao, Haifeng; Shan, Chongxin; Shen, Dezhen

2018-03-28

The generation of hot electrons from metal nanostructures through plasmon decay provided a direct interfacial charge transfer mechanism, which no longer suffers from the barrier height restrictions observed for metal/semiconductor interfaces. Metal plasmon-mediated energy conversion with higher efficiency has been proposed as a promising alternative to construct novel optoelectronic devices, such as photodetectors, photovoltaic and photocatalytic devices, etc. However, the realization of the electrically-driven generation of hot electrons, and the application in light-emitting devices remain big challenges. Here, hybrid architectures comprising individual Ga-doped ZnO (ZnO:Ga) microwires via metal quasiparticle film decoration were fabricated. The hottest spots could be formed towards the center of the wires, and the quasiparticle films were converted into physically isolated nanoparticles by applying a bias onto the wires. Thus, the hot electrons became spatially localized towards the hottest regions, leading to a release of energy in the form of emitting photons. By adjusting the sputtering times and appropriate alloys, such as Au and Ag, wavelength-tunable emissions could be achieved. To exploit the EL emission characteristics, metal plasmons could be used as active elements to mediate the generation of hot electrons from metal nanostructures, which are located in the light-emitting regions, followed by injection into ZnO:Ga microwire-channels; thus, the production of plasmon decay-induced hot-electrons could function as an efficient approach to dominate emission wavelengths. Therefore, by introducing metal nanostructure decoration, individual ZnO:Ga microwires can be used to construct wavelength-tunable fluorescent emitters. The hybrid architectures of metal-ZnO micro/nanostructures offer a fantastic candidate to broaden the potential applications of semiconducting optoelectronic devices, such as photovoltaic devices, photodetectors, optoelectronic sensors, etc.

Convectively driven PCR thermal-cycling

DOEpatents

Benett, William J.; Richards, James B.; Milanovich, Fred P.

2003-07-01

A polymerase chain reaction system provides an upper temperature zone and a lower temperature zone in a fluid sample. Channels set up convection cells in the fluid sample and move the fluid sample repeatedly through the upper and lower temperature zone creating thermal cycling.

Improvements to a Response Surface Thermal Model for Orion Mated to the International Space Station

NASA Technical Reports Server (NTRS)

Miller, StephenW.; Walker, William Q.

2011-01-01

This study is an extension of previous work to evaluate the applicability of Design of Experiments (DOE)/Response Surface Methodology to on-orbit thermal analysis. The goal was to determine if the methodology could produce a Response Surface Equation (RSE) that predicted the thermal model temperature results within +/-10 F. An RSE is a polynomial expression that can then be used to predict temperatures for a defined range of factor combinations. Based on suggestions received from the previous work, this study used a model with simpler geometry, considered polynomials up to fifth order, and evaluated orbital temperature variations to establish a minimum and maximum temperature for each component. A simplified Outer Mold Line (OML) thermal model of the Orion spacecraft was used in this study. The factors chosen were the vehicle's Yaw, Pitch, and Roll (defining the on-orbit attitude), the Beta angle (restricted to positive beta angles from 0 to 75), and the environmental constants (varying from cold to hot). All factors were normalized from their native ranges to a non-dimensional range from -1.0 to 1.0. Twenty-three components from the OML were chosen and the minimum and maximum orbital temperatures were calculated for each to produce forty-six responses for the DOE model. A customized DOE case matrix of 145 analysis cases was developed which used analysis points at the factor corners, mid-points, and center. From this data set, RSE s were developed which consisted of cubic, quartic, and fifth order polynomials. The results presented are for the fifth order RSE. The RSE results were then evaluated for agreement with the analytical model predictions to produce a +/-3(sigma) error band. Forty of the 46 responses had a +/-3(sigma) value of 10 F or less. Encouraged by this initial success, two additional sets of verification cases were selected. One contained 20 cases, the other 50 cases. These cases were evaluated both with the fifth order RSE and with the analytical model. For the maximum temperature predictions, 12 of the 23 components had all predictions within +/-10 F and 17 were within +/-20 F. For the minimum temperature predictions, only 4 of the 23 components (the four radiator temperatures), were within the 10 F goal. The maximum temperature RSEs were then run through 59,049 screening cases. The RSE predictions were then filtered to find 55 cases that produced the hottest temperatures. These 55 cases were then analyzed using the thermal model and the results compared against the RSE predictions. As noted earlier, 12 of the 23 responses were within +/-10 F at 17 within +/-20 F. These results demonstrate that if properly formulated, an RSE can provide a reliable, fast temperature prediction. Despite this progress, additional work is needed to determine why the minimum temperatures responses and 6 of the hot temperature responses did not produce reliable RSEs. Recommend focus areas are the model itself (arithmetic vs. diffusion nodes) and seeking consultations with statistical application experts.

ANSYS-Based Simulation and Optimization on Temperature Field of Amorphous Ingot Made by Water Quenching

NASA Astrophysics Data System (ADS)

Zhao, W.; Sun, Z.; Tang, Z.; Liaw, P. K.; Li, J.; Liu, R. P.; Li, Gong

2014-05-01

2D finite element analysis was conducted on the temperature field to create an amorphous ingot by vacuum water quenching. An optimized analysis document was then written by ANSYS parametric design language, and the optimal design modules of ANSYS were used to study the inside diameter and wall thickness of the quartz tube, as well as the water temperature. The microstructure and the phase structure of the amorphous ingot were evaluated by scanning electron microscopy and X-ray diffraction, respectively. Results show that during the cooling process, the thinner wall thickness, smaller diameter of the ingot, or lower temperature of the water environment can result in higher cooling rate at a given temperature. Besides, the gap between the different cooling rates induced by wall thickness or diameter of the ingot narrows down as the temperature decreases, and the gap between the different cooling rates induced by temperature of the water environment remains constant. The process parameters in creating an amorphous ingot, which is optimized by the finite element analysis on the temperature field, are reliable.

Low-cost Electromagnetic Heating Technology for Polymer Extrusion-based Additive Manufacturing

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

Carter, William G.; Rios, Orlando; Akers, Ronald R.

To improve the flow of materials used in in polymer additive manufacturing, ORNL and Ajax Tocco created an induction system for heating fused deposition modeling (FDM) nozzles used in polymer additive manufacturing. The system is capable of reaching a temperature of 230 C, a typical nozzle temperature for extruding ABS polymers, in 17 seconds. A prototype system was built at ORNL and sent to Ajax Tocco who analyzed the system and created a finalized power supply. The induction system was mounted to a PrintSpace Altair desktop printer and used to create several test parts similar in quality to those createdmore » using a resistive heated nozzle.« less

Controlled Electrochemical Deformation of Liquid-Phase Gallium.

PubMed

Chrimes, Adam F; Berean, Kyle J; Mitchell, Arnan; Rosengarten, Gary; Kalantar-zadeh, Kourosh

2016-02-17

Pure gallium is a soft metal with a low temperature melting point of 29.8 °C. This low melting temperature can potentially be employed for creating optical components with changeable configurations on demand by manipulating gallium in its liquid state. Gallium is a smooth and highly reflective metal that can be readily maneuvered using electric fields. These features allow gallium to be used as a reconfigurable optical reflector. This work demonstrates the use of gallium for creating reconfigurable optical reflectors manipulated through the use of electric fields when gallium is in a liquid state. The use of gallium allows the formed structures to be frozen and preserved as long as the temperature of the metal remains below its melting temperature. The lens can be readily reshaped by raising the temperature above the melting point and reapplying an electric field to produce a different curvature of the gallium reflector.

Room-temperature creation and spin-orbit torque-induced manipulation of skyrmions in thin film

NASA Astrophysics Data System (ADS)

Yu, Guoqiang; Upadhyaya, Pramey; Li, Xiang; Li, Wenyuan; Im, Se Kwon K.; Fan, Yabin; Wong, Kin L.; Tserkovnyak, Yaroslav; Amiri, Pedram Khalili; Wang, Kang L.

Magnetic skyrmions, which are topologically protected spin texture, are promising candidates for ultra-low energy and ultra-high density magnetic data storage and computing applications1, 2. To date, most experiments on skyrmions have been carried out at low temperatures. The choice of materials available is limited and there is a lack of electrical means to control of skyrmions. Here, we experimentally demonstrate a method for creating skyrmion bubbles phase in the ferromagnetic thin film at room temperature. We further demonstrate that the created skyrmion bubbles can be manipulated by electric current. This room-temperature creation and manipulation of skyrmion in thin film is of particular interest for applications, being suitable for room-temperature operation and compatible with existing semiconductor manufacturing tools. 1. Nagaosa, N., Tokura, Y. Nature Nanotechnology 8, 899-911 (2013). 2. Fert, A., et al., Nature Nanotechnology 8, 152-156 (2013).

Melting Behavior of Volcanic Ash relevant to Aviation Ash Hazard

NASA Astrophysics Data System (ADS)

Song, W.; Hess, K.; Lavallee, Y.; Cimarelli, C.; Dingwell, D. B.

2013-12-01

Volcanic ash is one of the major hazards caused by volcanic eruptions. In particular, the threat to aviation from airborne volcanic ash has been widely recognized and documented. In the past 12 years, more than 60 modern jet airplanes, mostly jumbo jets, have been damaged by drifting clouds of volcanic ash that have contaminated air routes and airport facilities. Seven of these encounters are known to have caused in-flight loss of engine power to jumbo jets carrying a total of more than 2000 passengers. The primary cause of engine thrust loss is that the glass in volcanic ash particles is generated at temperatures far lower than the temperatures in the combustion chamber of a jet engine ( i.e. > 1600 oC) and when the molten volcanic ash particles leave this hottest section of the engine, the resolidified molten volcanic ash particles will be accumulated on the turbine nozzle guide vanes, which reduced the effective flow of air through the engine ultimately causing failure. Thus, it is essential to investigate the melting process and subsequent deposition behavior of volcanic ash under gas turbine conditions. Although few research studies that investigated the deposition behavior of volcanic ash at the high temperature are to be found in public domain, to the best our knowledge, no work addresses the formation of molten volcanic ash. In this work, volcanic ash produced by Santiaguito volcano in Guatemala in November 8, 2012 was selected for study because of their recent activity and potential hazard to aircraft safety. We used the method of accessing the behavior of deposit-forming impurities in high temperature boiler plants on the basis of observations of the change in shape and size of a cylindrical coal ash to study the sintering and fusion phenomena as well as determine the volcanic ash melting behavior by using characteristic temperatures by means of hot stage microscope (HSM), different thermal analysis (DTA) and Thermal Gravimetric Analysis (TGA) to investigate the sintering process of volcanic ash. In order to analyze the mineral transformation and microstructure evolution, the qualitative as well as quantitative crystalline phase analysis of volcanic ash samples directly taken from furnace by per 100 oC in the range of between 100 and 1400 oC as well as evaluation of microstructure of volcanic ash taken from from furnace by per 20 oC in the range of between 1000 and 1300 oC has been made by X-ray diffraction (XRD) and observed by scanning electron microscopy (SEM). Finally, we obtain the viscosity temperature curve for volcanic ash during melting process on the basis of the characteristic temperature obtained by HSM.

A New Formation Mechanism for the Hottest Horizontal-Branch Stars

NASA Technical Reports Server (NTRS)

Sweigart, Allen V.; Oegerle, William R. (Technical Monitor)

2002-01-01

Hot subluminous stars lying up to 0.7 mag below the extreme horizontal branch (EHB) are found in the ultraviolet color-magnitude diagrams (CMDs) of both omega Cen and NGC 2808. In order to investigate the origin of these subluminous stars, we have constructed a detailed set of evolutionary sequences that follow the evolution of low-mass stars continuously from the zero-age main sequence through the helium-core flash to the HB for a wide range in the mass loss along the red-giant branch (RGB). Stars with the largest mass loss evolve off the RGB to high effective temperatures before igniting helium in their cores. Our results indicate that the subluminous EHB stars, as well as the high temperature gap along the EHB of NGC 2808, can be explained if these stars undergo a late helium-core flash while descending the white-dwarf cooling curve. Under these conditions the convection zone produced by the main helium flash will penetrate into the stellar envelope, thereby mixing most, if not all, of the envelope hydrogen into the hot helium-burning interior, where it is rapidly consumed. This phenomenon is analogous to the 'born-again' scenario for producing hydrogen-deficient stars following a very late helium-shell flash. This 'flash mixing' of the envelope during a late helium-core flash greatly enhances the envelope helium and carbon abundances and, as a result, leads to a discontinuous increase in the HB effective temperature. We argue that the hot HB gap observed in NGC 2808 is associated with this theoretically predicted dichotomy in the RB properties. Using new helium- and carbon-rich stellar atmospheres, we show that the changes in the envelope abundances due to flash mixing will suppress the ultraviolet flux in the spectra of hot EHB stars. We suggest that such changes in the emergent spectral energy distribution are primarily responsible for explaining the hot subluminous EHB stars in omega Cen and NGC 2808. Moreover, we demonstrate that models without flash mixing lie, at most, only approximately 0.1 mag below the EHB, and hence fail to explain the observations.

New Measurements of Mars Thermospheric Variability from MAVEN EUVM Solar Occultations

NASA Astrophysics Data System (ADS)

Thiemann, E.; Eparvier, F. G.; Andersson, L.; Pilinski, M.; Chamberlin, P. C.; Fowler, C. M.; Dominique, M.; Bougher, S. W.; Gröller, H.; Girazian, Z.; Lillis, R. J.

2017-12-01

The Mars thermosphere encompasses both the coldest and hottest regions of the Mars neutral atmosphere, where temperatures warm from below 150 K at the well-mixed homopause to 300 K at the collisionless exobase, and change by comparable magnitudes over the diurnal cycle. In this dynamic and highly-structured region, atoms and molecules are accelerated by a number of processes, potentially leading to escape and permanent loss to space. Increasingly, evidence shows that atmospheric escape to space has resulted in the loss of a substantial portion of Mars's atmosphere over the planet's history. Given that the thermosphere is the neutral reservoir for atmospheric escape, understanding how and why it varies is crucial for understanding how Mars's climate has evolved over time. The Mars Atmosphere and Volatile EvolutioN (MAVEN) orbiter's Extreme Ultraviolet (EUV) Monitor (EUVM) has recently demonstrated the capability to measure thermospheric density from 100 to 200 km with solar occultations of its 17-22 nm channel. These measurements are routine, inherently constrained to either 06:00 or 18:00 Local Time, and span all latitudes, a number of which have been revisited multiple times over the past 3 Earth years due to MAVEN's orbital precession. These factors, coupled with uncertainties in retrieved densities below 10%, make MAVEN EUVM occultations ideal for tracking both long-term and latitudinal thermospheric variability. Some notable trends revealed by the EUVM occultation data are variations in poleward warming due to changes in global circulation patterns, planetary-scale waves due to varying gravity wave or tidal forcing, and temperature due to solar EUV variability. In this study, we present these new measurements in detail. We begin by briefly presenting the measurement methods and uncertainties, and show an overview of the measurements made to-date, putting them in the context of observations made by other missions, other instruments onboard MAVEN, and the newly arrived ExoMars Trace Gas Orbiter (TGO). We then show observations of latitudinal and seasonal temperature and density variability made over the MAVEN mission, and discuss the possible underlying causes. We conclude by discussing plans to make these new data publically available as an official MAVEN data product.

Shock-Induced Phase Transitions in the Martian Meteorite Tissint: Mechanisms and Constraints on Shock Pressure

NASA Astrophysics Data System (ADS)

Sharp, T. G.; Hu, J.; Walton, E. L.

2013-12-01

Martian meteorites are important samples for understanding the origin and age of the Martian crust. All of these samples have been shocked to some degree during their ejection from Mars or earlier. Tissint, a picritic shergottite, has many high-pressure phases that have been used to constrain shock conditions and suggest a deep crustal origin [1] and to argue for multiple impact events [2]. Here we investigate the products and mechanisms of various olivine transformation reactions. Olivine in and adjacent to shock-melt veins and pockets is transformed into high-pressure minerals. In the hottest parts of the sample, olivine dissociated into 50-nm crystals of magnesiowüstite intergrown with either a pyroxene-composition glass or with low-Ca clinopyroxene. In both cases, the olivine is inferred to have transformed to silicate perovskite + magnesiowüstite during shock with subsequent breakdown of the perovskite after pressure release. Olivine along the margins of shock veins transformed into ringwoodite. Polycrystalline ringwoodite formed at the olivine-melt interface wheras coherent ringwoodite lamellae formed farther from the melt. These ringwoodite lamellae have the same topotaxial relationship to olivine as seen in static high-pressure experiments [3] and shocked meteorites [4]: (100)Ol || {111}Rw and [011]Ol || <110>Rw. The various olivine reactions can be explained by a single shock to above 24 GPa where only the highest temperatures allowed the dissociation of olivine to silicate-perovskite plus magnesiowüstite. The silicate perovskite in the melt pocket transformed to pyroxene because the melt pocket remained very hot after pressure release. At lower temperatures, the kinetically easier polymorphic transformation of olivine to metastable ringwoodite occurred. At the lowest temperatures, this reaction was facilitated by nucleation of ringwoodite lamellae on stacking faults in olivine. The variation in assemblages that we see are consistent with a single shock and a relatively short shock pulse. References: [1] Baziotis1, I. P. et. al 2013 Nature Communications 4:1404, [2] El Goresey, A. et. al 2013 #1037. 44th LPSC. [3] Kerschhofer, L. et. al 1996 Science 274, 79-81. [4] Miyahara et. al, 2010 EPSL. 295, 321-327.

Io in the near infrared: Near-Infrared Mapping Spectrometer (NIMS) results from the Galileo flybys in 1999 and 2000

USGS Publications Warehouse

Lopes, R.M.C.; Kamp, L.W.; Doute, S.; Smythe, W.D.; Carlson, R.W.; McEwen, A.S.; Geissler, P.E.; Kieffer, S.W.; Leader, F.E.; Davies, A.G.; Barbinis, E.; Mehlman, R.; Segura, M.; Shirley, J.; Soderblom, L.A.

2001-01-01

Galileo's Near-Infrared Mapping Spectrometer (NIMS) observed Io during the spacecraft's three flybys in October 1999, November 1999, and February 2000. The observations, which are summarized here, were used to map the detailed thermal structure of active volcanic regions and the surface distribution of SO2 and to investigate the origin of a yet unidentified compound showing an absorption feature at ???1 ??m. We present a summary of the observations and results, focusing on the distribution of thermal emission and of SO2 deposits. We find high eruption temperatures, consistent with ultramafic volcanism, at Pele. Such temperatures may be present at other hot spots, but the hottest areas may be too small for those temperatures to be detected at the spatial resolution of our observations. Loki is the site of frequent eruptions, and the low thermal emission may represent lavas cooling on the caldera's surface or the cooling crust of a lava lake. High-resolution spectral observations of Emakong caldera show thermal emission and SO2 within the same pixels, implying that patches of SO2 frost and patches of cooling lavas or sulfur flows are present within a few kilometers from one another. Thermal maps of Prometheus and Amirani show that these two hot spots are characterized by long lava flows. The thermal profiles of flows at both locations are consistent with insulated flows, with the Amirani flow field having more breakouts of fresh lava along its length. Prometheus and Amirani each show a white ring at visible wavelengths, while SO2 distribution maps show that the highest concentration of SO2 in both ring deposits lies outside the white portion. Visible measurements at high phase angles show that the white deposit around Prometheus extends into the SO2 ring. This suggests that the deposits are thin and that compositional or grain size variations may occur in the radial direction. SO2 mapping of the Chaac region shows that the interior of a caldera adjacent to Chaac has almost pure SO2. The deposit appears to be topographically controlled, suggesting a possible origin by liquid flow. Copyright 2001 by the American Geophysical Union.

Investigations of Very High Enthalpy Geothermal Resources in Iceland.

NASA Astrophysics Data System (ADS)

Elders, W. A.; Fridleifsson, G. O.

2012-12-01

The Iceland Deep Drilling Project (IDDP) is investigating the economic feasibility of producing electricity from supercritical geothermal reservoirs. Earlier modeling indicates that the power output of a geothermal well producing from a supercritical reservoir could potentially be an order of magnitude greater than that from a conventional hot geothermal reservoir, at the same volumetric flow rate. However, even in areas with an unusually high geothermal gradient, for normal hydrostatic pressure gradients reaching supercritical temperatures and pressures will require drilling to depths >4 km. In 2009 the IDDP attempted to drill the first deep supercritical well, IDDP-01, in the caldera of the Krafla volcano, in NE Iceland. However drilling had to be terminated at only 2.1 km depth when ~900°C rhyolite magma flowed into the well. Our studies indicate that this magma formed by partial melting of hydrothermally altered basalts within the Krafla caldera. Although this well was too shallow to reach supercritical pressures, it is highly productive, and is estimated to be capable of generating up to 36 MWe from the high-pressure, superheated steam produced from the upper contact zone of the intrusion. With a well-head temperature of ~440°C, it is at present apparently the hottest producing geothermal well in the world. A pilot plant is investigating the optimal utilization of this magmatically heated resource. A special issue of the journal Geothermics with 16 papers reporting on the IDDP-01 is in preparation. However, in order to continue the search for supercritical geothermal resources, planning is underway to drill a 4.5 km deep well at Reykjanes in SW Iceland in 2013-14. Although drilling deeper towards the heat source of this already developed high-temperature geothermal field will be more expensive, if a supercritical resource is found, this cost increase should be offset by the considerable increase in the power output and lifetime of the Reykjanes geothermal reservoir, without increasing its environmental foot print. If these efforts are successful, in future such very high enthalpy geothermal systems worldwide could become significant energy resources, where ever suitable young volcanic rocks occur, such as in the western USA, Hawaii, and Alaska.

[Advances in the research on hyperspectral remote sensing in biodiversity and conservation].

PubMed

He, Cheng; Feng, Zhong-Ke; Yuan, Jin-Jun; Wang, Jia; Gong, Yin-Xi; Dong, Zhi-Hai

2012-06-01

With the species reduction and the habitat destruction becoming serious increasingly, the biodiversity conservation has become one of the hottest topics. Remote sensing, the science of non-contact collection information, has the function of corresponding estimates of biodiversity, building model between species diversity relationship and mapping the index of biodiversity, which has been used widely in the field of biodiversity conservation. The present paper discussed the application of hyperspectral technology to the biodiversity conservation from two aspects, remote sensors and remote sensing techniques, and after, enumerated successful applications for emphasis. All these had a certain reference value in the development of biodiversity conservation.

THE HOT R CORONAE BOREALIS STAR DY CENTAURI IS A BINARY

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

Kameswara Rao, N.; Lambert, David L.; McArthur, Barbara

2012-11-20

The remarkable hot R Coronae Borealis (RCB) star DY Cen is revealed to be the first and only binary system to be found among the RCB stars and their likely relatives, including the extreme helium stars and the hydrogen-deficient carbon stars. Radial velocity determinations from 1982 to 2010 have shown that DY Cen is a single-lined spectroscopic binary in an eccentric orbit with a period of 39.67 days. It is also one of the hottest and most H-rich member of the class of RCB stars. The system may have evolved from a common envelope to its current form.

Cloud Computing: An Overview

NASA Astrophysics Data System (ADS)

Qian, Ling; Luo, Zhiguo; Du, Yujian; Guo, Leitao

In order to support the maximum number of user and elastic service with the minimum resource, the Internet service provider invented the cloud computing. within a few years, emerging cloud computing has became the hottest technology. From the publication of core papers by Google since 2003 to the commercialization of Amazon EC2 in 2006, and to the service offering of AT&T Synaptic Hosting, the cloud computing has been evolved from internal IT system to public service, from cost-saving tools to revenue generator, and from ISP to telecom. This paper introduces the concept, history, pros and cons of cloud computing as well as the value chain and standardization effort.

Lithium in M67

NASA Technical Reports Server (NTRS)

Hobbs, L. M.; Pilachowski, Catherine

1986-01-01

Echelle spectra recorded at the Li I 6707-A line are reported for seven main-sequence members and one cool subgiant in M67. The spectral types of the seven dwarfs studied range from about F8 at the turnoff point to about G5. The principal result is that the average lithium abundance in the three hottest main-sequence stars is 0.45 x 10 to the -9th. Any enrichment of lithium in the gas of the Galactic disk in the last 5 Gyr therefore has not exceeded a factor of about two and probably is entirely negligible, when the corresponding results for NGC 752 and the Hyades are taken into account.

Superhot Drilling in Iceland, the Experience of the Iceland Deep Drilling Project.

NASA Astrophysics Data System (ADS)

Elders, W. A.; Friðleifsson, G. Ó.; Zierenberg, R. A.; Fowler, A. P.

2017-12-01

The Iceland Deep Drilling Project aims to improve geothermal economics by producing supercritical fluids (www.iddp.is). Supercritical wells could yield an order of magnitude more usable energy than that from conventional geothermal wells because of higher enthalpy and enhanced flow properties. In 2009, the IDDP-1 well failed to reach supercritical conditions in the Krafla caldera in NE Iceland, after encountering rhyolite magma at only 2.1 km depth. The completed geothermal well became the world's hottest and produced superheated steam with a wellhead temperature of 452°C and flow sufficient to generate 35 MWe. The IDDP next moved SW to the Reykjanes Peninsula, the landward extension of the Mid-Atlantic Ridge, where it is possible to study an analog of the roots of a black smoker. Reykjanes is unique among Icelandic geothermal systems in being recharged by seawater, which has a critical point of 406°C at 298 bars. Drilling began by deepening an existing 2.5 km deep production well to 3 km depth, and then angling it towards the main upflow zone of the system, for a total slant depth of 4,659 m. Total circulation losses were encountered below 3 km that could not be cured by lost circulation materials or by multiple cement jobs. Accordingly, drilling continued to total depth without return of drill cuttings. We attempted 13 core runs below 3 km depth, only half of which recovered core. The cores are basalts and dolerites with alteration ranging from lower greenschist facies to lower amphibolite facies, suggesting formation temperatures >450°C. After the end of drilling in January 2017, following only six days of heating, supercritical conditions (426°C at 340 bars) were measured in the well at a depth of 4.5 km. The well has not yet been allowed to equilibrate to full in situ temperature. A perforated liner was inserted to 4,570 m, depth to facilitate temperature cycling to enhance permeability at depth through thermal cracking. In 2018 this will be followed by a flow test and eventual production of the well. The project is co-funded by the DEEPEGS project (EU H2020), HS Orka (the field operator), Statoil, the IDDP consortium, and the ICDP. Planning is underway to drill IDDP-3 at Hellisheidi.

Human body temperature and new approaches to constructing temperature-sensitive bacterial vaccines

PubMed Central

White, Matthew D.; Bosio, Catharine M.; Duplantis, Barry N.

2012-01-01

Many of the live human and animal vaccines that are currently in use are attenuated by virtue of their temperature-sensitive (TS) replication. These vaccines are able to function because they can take advantage of sites in mammalian bodies that are cooler than the core temperature, where TS vaccines fail to replicate. In this article, we discuss the distribution of temperature in the human body, and relate how the temperature differential can be exploited for designing and using TS vaccines. We also examine how one of the coolest organs of the body, the skin, contains antigen-processing cells that can be targeted to provoke the desired immune response from a TS vaccine. We describe traditional approaches to making TS vaccines, and highlight new information and technologies that are being used to create a new generation of engineered TS vaccines. We pay particular attention to the recently described technology of substituting essential genes from Arctic bacteria for their homologues in mammalian pathogens as a way of creating TS vaccines. PMID:21626408

Human body temperature and new approaches to constructing temperature-sensitive bacterial vaccines.

PubMed

White, Matthew D; Bosio, Catharine M; Duplantis, Barry N; Nano, Francis E

2011-09-01

Many of the live human and animal vaccines that are currently in use are attenuated by virtue of their temperature-sensitive (TS) replication. These vaccines are able to function because they can take advantage of sites in mammalian bodies that are cooler than the core temperature, where TS vaccines fail to replicate. In this article, we discuss the distribution of temperature in the human body, and relate how the temperature differential can be exploited for designing and using TS vaccines. We also examine how one of the coolest organs of the body, the skin, contains antigen-processing cells that can be targeted to provoke the desired immune response from a TS vaccine. We describe traditional approaches to making TS vaccines, and highlight new information and technologies that are being used to create a new generation of engineered TS vaccines. We pay particular attention to the recently described technology of substituting essential genes from Arctic bacteria for their homologues in mammalian pathogens as a way of creating TS vaccines.

An FPGA Noise Resistant Digital Temperature Sensor with Auto Calibration

DTIC Science & Technology

2012-03-01

temperature sensor [6] . . . . . . . . . . . . . . 14 9 Two different digital temperature sensor placement algorithms: (a) Grid placement (b) Optimal...create a grid over the FPGA. While this method works reasonably well, it requires many sensors, some of which are unnecessary. The optimal placement, on...temperature sensor placement algorithms: (a) Grid placement (b) Optimal Placement [7] 16 2.4 Summary Integrated circuits’ sensitivity to temperatures has

Vulnerability of California specialty crops to projected mid-century temperature changes

USDA-ARS?s Scientific Manuscript database

Increasing global temperatures are likely to have major impacts on agriculture, but the effects will vary by crop and location. This paper describes the temperature sensitivity and exposure of selected specialty crops in California. We used literature synthesis to create several sensitivity indices ...

Thermal comfort along the marathon course of the 2020 Tokyo Olympics

NASA Astrophysics Data System (ADS)

Honjo, Tsuyoshi; Seo, Yuhwan; Yamasaki, Yudai; Tsunematsu, Nobumitsu; Yokoyama, Hitoshi; Yamato, Hiroaki; Mikami, Takehiko

2018-04-01

The Olympic Games will be held in Tokyo in 2020 and the period will be the hottest period of the year in Japan. Marathon is a sport with a large heat load, and it is said that the risk of heat stroke rises more than other sports activities. The thermal environment of the 2020 Tokyo Olympic marathon course is analyzed by using wet-bulb globe temperature (WBGT) and Universal Thermal Climate Index (UTCI) map of the center area of Tokyo. The change due to the place, the effect of the shadow of the building, and the position on the course was analyzed from the distribution of WBGT and UTCI in the short-term analysis of sunny day from August 2 to August 6, 2014. To make the distribution map, we calculated distributions of sky view factor and mean radiant temperature of the 10 km × 7.5 km analyzed area in the center of Tokyo. Distributions of air temperature and humidity are calculated from Metropolitan Environmental Temperature and Rainfall Observation System data, which is a high-resolution measurement network. It was possible to incorporate the local variation of temperature and humidity of the analyzed area. In the result, the WBGT is about 1 °C lower and the UTCI is about 4-8 °C lower in the shadow of buildings from 9:00 to 10:00 than in the sunny side. As a cooling method, making a shadow is a relatively effective method. The variation along the course considering the distribution of meteorological data within the area is about 0.5 °C WBGT and 1 °C UTCI range. If we allow the error of this range, one-point meteorological data can be applied for the estimation along the course. Passing the right side (left side in the case of return) of the course could keep the accumulated value slightly lower along the course in the morning because the marathon course roughly runs from west to east and buildings' shadow is on the relatively right side (south side). But practically, the effect of changing the position on the course was small. The long-term analysis on the degree of risk for each hour was also carried out by using one-point data of the first 10 days of August from 2007 to 2016. The risk increased rapidly after 8:00. It will be safer if the marathon race is finished before 9:00 or if the race is held after 19:00.

Thermal comfort along the marathon course of the 2020 Tokyo Olympics.

PubMed

Honjo, Tsuyoshi; Seo, Yuhwan; Yamasaki, Yudai; Tsunematsu, Nobumitsu; Yokoyama, Hitoshi; Yamato, Hiroaki; Mikami, Takehiko

2018-04-17

The Olympic Games will be held in Tokyo in 2020 and the period will be the hottest period of the year in Japan. Marathon is a sport with a large heat load, and it is said that the risk of heat stroke rises more than other sports activities. The thermal environment of the 2020 Tokyo Olympic marathon course is analyzed by using wet-bulb globe temperature (WBGT) and Universal Thermal Climate Index (UTCI) map of the center area of Tokyo. The change due to the place, the effect of the shadow of the building, and the position on the course was analyzed from the distribution of WBGT and UTCI in the short-term analysis of sunny day from August 2 to August 6, 2014. To make the distribution map, we calculated distributions of sky view factor and mean radiant temperature of the 10 km × 7.5 km analyzed area in the center of Tokyo. Distributions of air temperature and humidity are calculated from Metropolitan Environmental Temperature and Rainfall Observation System data, which is a high-resolution measurement network. It was possible to incorporate the local variation of temperature and humidity of the analyzed area. In the result, the WBGT is about 1 °C lower and the UTCI is about 4-8 °C lower in the shadow of buildings from 9:00 to 10:00 than in the sunny side. As a cooling method, making a shadow is a relatively effective method. The variation along the course considering the distribution of meteorological data within the area is about 0.5 °C WBGT and 1 °C UTCI range. If we allow the error of this range, one-point meteorological data can be applied for the estimation along the course. Passing the right side (left side in the case of return) of the course could keep the accumulated value slightly lower along the course in the morning because the marathon course roughly runs from west to east and buildings' shadow is on the relatively right side (south side). But practically, the effect of changing the position on the course was small. The long-term analysis on the degree of risk for each hour was also carried out by using one-point data of the first 10 days of August from 2007 to 2016. The risk increased rapidly after 8:00. It will be safer if the marathon race is finished before 9:00 or if the race is held after 19:00.

Climate-host mapping of Phytophthora ramorum, causal agent of sudden oak death

Treesearch

Glenn Fowler; Roger Magarey; Manuel Colunga

2006-01-01

Phytophthora ramorum infection was modeled using the NAPPFAST system for the conterminous United States. Parameters used to model P. ramorum infection were: leaf wetness, minimum temperature, optimum temperature and maximum temperature over a specified number of accumulated days. The model was used to create maps showing the...

Variation of stream temperature among mesoscale habitats within stream reaches: southern Appalachians

Treesearch

S. Lynsey Long; C. Rhett. Jackson

2014-01-01

Stream mesoscale habitats have systematic topographic relationships to hyporheic flow patterns, which may create predictable temperature variation between mesoscale habitat types. We investigated whether systematic differences in temperature metrics occurred between mesoscale habitats within reaches of small streams tributary to the upper Little Tennessee River,...

Health risks and precautions for visitors to the Tokyo 2020 Olympic and Paralympic Games.

PubMed

Nakamura, Sachiko; Wada, Koji; Yanagisawa, Naoki; Smith, Derek R

In 2020, Japan will host the Tokyo Olympic and Paralympic Games in 2020 (Tokyo 2020) which will involve a large population influx from various countries to Tokyo, the most populated city in Japan. We summarize the potential health risks for visitors to Tokyo 2020, related to communicable disease risks and other health threats, based on recent national and local surveillance reports. We reviewed up-to-date surveillance reports published by the National Institute of Infectious Diseases and Tokyo Metropolitan Infectious Disease Surveillance Center. Communicable disease risks for vaccine-preventable illnesses such as measles and rubella, as well as food and waterborne diseases represent the most likely risks. The risk of acquiring vector-borne diseases is considered low in Japan. On the other hand, however, heat-related illness represents a potential risk, as Tokyo 2020 is scheduled during the hottest season in Japan, with temperatures generally expected to exceed 30 °C. Maintaining an up-to-date routine vaccination schedule is highly recommended for visitors attending the Tokyo 2020 and appropriate hygiene measures for food and waterborne diseases as well as health promotion for heat-related illness. It may also be useful to increase the number of multilingual triage clinicians whom can be placed within emergency departments during the Tokyo 2020 to provide first contact services and coordination of emergency care among non-Japanese speaking visitors to Tokyo. Copyright © 2018. Published by Elsevier Ltd.

The crabs that live where hot and cold collide.

PubMed

Thurber, Andrew R

2015-07-01

The distribution of Kiwa tyleri with the large male individual in the high-temperature flow (right hand side - fluid flow indicated by shimmering water) and the mixed sex assemblage (left). Note the heavy coat of epibiotic bacteria (grey colouring) on the individual in the hottest section of the vent, as expected from being closest to the sulphide needed to sustain the epibiotic bacteria that this species harvests for its food. Image courtesy of Dr. L. Marsh (Credit: NERC ChEsSo Consortium). In Focus: Marsh, L., Copley, J.T., Tyler, P.A. & Thatje, S. (2015) In hot and cold water: differential life-history traits are key to success in contrasting thermal deep-sea environments. Journal of Animal Ecology, 84, 898-913. Southern Ocean hydrothermal vents juxtapose two extremes - intense food-poor cold and scalding food-rich oases. At these vents, Marsh et al. (2015) found a community of Kiwa (Yeti) crabs that separated themselves along this gradient with the largest males sitting in hot, food-rich waters, while smaller males and females co-occur in an intermediate zone of warmth. However, as their eggs start to develop, females embark away from the vent to the food-poor yet stable cold of the Southern Ocean. This species has found an intriguing way to balance foraging risk and population persistence at the interface of hot and cold. © 2015 The Author. Journal of Animal Ecology © 2015 British Ecological Society.

TESTING SCALING RELATIONS FOR SOLAR-LIKE OSCILLATIONS FROM THE MAIN SEQUENCE TO RED GIANTS USING KEPLER DATA

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

Huber, D.; Bedding, T. R.; Stello, D.

2011-12-20

We have analyzed solar-like oscillations in {approx}1700 stars observed by the Kepler Mission, spanning from the main sequence to the red clump. Using evolutionary models, we test asteroseismic scaling relations for the frequency of maximum power ({nu}{sub max}), the large frequency separation ({Delta}{nu}), and oscillation amplitudes. We show that the difference of the {Delta}{nu}-{nu}{sub max} relation for unevolved and evolved stars can be explained by different distributions in effective temperature and stellar mass, in agreement with what is expected from scaling relations. For oscillation amplitudes, we show that neither (L/M){sup s} scaling nor the revised scaling relation by Kjeldsen andmore » Bedding is accurate for red-giant stars, and demonstrate that a revised scaling relation with a separate luminosity-mass dependence can be used to calculate amplitudes from the main sequence to red giants to a precision of {approx}25%. The residuals show an offset particularly for unevolved stars, suggesting that an additional physical dependency is necessary to fully reproduce the observed amplitudes. We investigate correlations between amplitudes and stellar activity, and find evidence that the effect of amplitude suppression is most pronounced for subgiant stars. Finally, we test the location of the cool edge of the instability strip in the Hertzsprung-Russell diagram using solar-like oscillations and find the detections in the hottest stars compatible with a domain of hybrid stochastically excited and opacity driven pulsation.« less

The Prospect of Y2SiO5-Based Materials as Protective Layer in Environmental Barrier Coatings

NASA Astrophysics Data System (ADS)

García, E.; Miranzo, P.; Osendi, M. I.

2013-06-01

Bulk yttrium monosilicate (Y2SiO5) possesses interesting properties, such as low thermal expansion coefficient and stability in water vapor atmospheres, which make it a promising protective layer for SiC-based composites, intended for the hottest parts in the future gas turbines. Because protective layers are commonly applied by thermal spraying techniques, it is important to analyze the changes in structure and properties that these methods may produce in yttrium silicate coatings. In this work, two SiO2-Y2O3 compositions were flame sprayed in the form of coatings and beads. In parallel, the beads were spark plasma sintered at relatively low temperature to obtain partially amorphous bulk specimens that are used as model bulk material. The thermal aging—air and water vapor atmosphere—caused extensive nucleation of Y2SiO5 and Y2Si2O7 in both the bulk and coating. The rich water vapor condition caused the selective volatilization of SiO2 from Y2Si2O7 at the specimen surface leaving a very characteristic micro-ridged Y2SiO5 zones—either in coatings or sintered bodies. An important increase in the thermal conductivity of the aged materials was measured. The results of this work may be used as a reference body for the production of Y2SiO5 coatings using thermal spraying techniques.

Temperature-profile detector

DOEpatents

Not Available

1981-01-29

Temperature profiles at elevated temperature conditions are monitored by use of an elongated device having two conductors spaced by the minimum distance required to normally maintain an open circuit between them. The melting point of one conductor is selected at the elevated temperature being detected, while the melting point of the other is higher. As the preselected temperature is reached, liquid metal will flow between the conductors creating short circuits which are detectable as to location.

Temperature profile detector

DOEpatents

Tokarz, Richard D.

1983-01-01

Temperature profiles at elevated temperature conditions are monitored by use of an elongated device having two conductors spaced by the minimum distance required to normally maintain an open circuit between them. The melting point of one conductor is selected at the elevated temperature being detected, while the melting point of the other is higher. As the preselected temperature is reached, liquid metal will flow between the conductors, creating short circuits which are detectable as to location.

Real-time modeling of heat distributions

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

Hamann, Hendrik F.; Li, Hongfei; Yarlanki, Srinivas

Techniques for real-time modeling temperature distributions based on streaming sensor data are provided. In one aspect, a method for creating a three-dimensional temperature distribution model for a room having a floor and a ceiling is provided. The method includes the following steps. A ceiling temperature distribution in the room is determined. A floor temperature distribution in the room is determined. An interpolation between the ceiling temperature distribution and the floor temperature distribution is used to obtain the three-dimensional temperature distribution model for the room.

Overshoot and Non-Overshoot Pathways to 1.5oC and Above: The Temperature Tunnel

NASA Astrophysics Data System (ADS)

Feijoo, F.; Edmonds, J.; Wise, M. A.; Mignone, B.; Kheshgi, H. S.

2017-12-01

We create 3000 temperature pathways that lead to a wide range of outcomes in 2100 from below 1.5oC to over 3oC. We use the Global Change Assessment Model (GCAM), which includes the HECTOR physical Earth system model, to generate emission, climate forcing and global temperature trajectories driven by a wide range of assumed carbon price trajectories. While no probability is estimated for the generated trajectories, we report the central estimate of temperature response to emissions from HECTOR. We find that despite the wide range of generated carbon emission trajectories, temperature pathways were constrained to a narrow range until shortly before mid-century. This "temperature tunnel" was the result of two phenomena: first, a narrow range of radiative forcing for 10-15 years created by the concurrent reduction of carbon and aerosol emissions; and second, the thermal lag of the climate response to radiative forcing change of roughly 10-15 years. Scenarios consistent with 1.5oC showed higher short-term temperatures than scenarios consistent with higher temperature outcomes. No scenarios were found that peak below approximately 1.9oC.

CHANGING PHASES OF ALIEN WORLDS: PROBING ATMOSPHERES OF KEPLER PLANETS WITH HIGH-PRECISION PHOTOMETRY

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

Esteves, Lisa J.; Mooij, Ernst J. W. De; Jayawardhana, Ray, E-mail: esteves@astro.utoronto.ca, E-mail: demooij@astro.utoronto.ca, E-mail: rayjay@yorku.ca

We present a comprehensive analysis of planetary phase variations, including possible planetary light offsets, using eighteen quarters of data from the Kepler space telescope. Our analysis found fourteen systems with significant detections in each of the phase curve components: planet’s phase function, secondary eclipse, Doppler boosting, and ellipsoidal variations. We model the full phase curve simultaneously, including primary and secondary transits, and derive albedos, day- and night-side temperatures and planet masses. Most planets manifest low optical geometric albedos (< 0.25), with the exception of Kepler-10b, Kepler-91b, and KOI-13b. We find that KOI-13b, with a small eccentricity of 0.0006 ± 0.0001,more » is the only planet for which an eccentric orbit is favored. We detect a third harmonic for HAT-P-7b for the first time, and confirm the third harmonic for KOI-13b reported in Esteves et al.: both could be due to their spin–orbit misalignments. For six planets, we report a planetary brightness peak offset from the substellar point: of those, the hottest two (Kepler-76b and HAT-P-7b) exhibit pre-eclipse shifts or on the evening-side, while the cooler four (Kepler-7b, Kepler-8b, Kepler-12b, and Kepler-41b) peak post-eclipse or on the morning-side. Our findings dramatically increase the number of Kepler planets with detected planetary light offsets, and provide the first evidence in the Kepler data for a correlation between the peak offset direction and the planet’s temperature. Such a correlation could arise if thermal emission dominates light from hotter planets that harbor hot spots shifted toward the evening-side, as theoretically predicted, while reflected light dominates cooler planets with clouds on the planet’s morning-side.« less

Coping with heat in the city: what can we learn from a survey immediately after a hot weather period for future heat waves?

NASA Astrophysics Data System (ADS)

Kunz-Plapp, Tina; Schipper, Hans; Hackenbruch, Julia

2015-04-01

Karlsruhe is one of the hottest cities in Germany with a temperature record of 40.2°C in August 2003. In 2013, two hot weather periods with continuous heat warnings by the German Weather Service for 7 and 8 days occurred during the second half of July and first 10 days of August 2013, and in early August the temperatures in Karlsruhe almost reached again the record of 40.2°C. To understand how citizens experienced the heat and what strategies they used to cope with the heat, we conducted a questionnaire survey on subjective heat stress and coping strategies immediately after the hot weather period. Based on a holistic approach the questionnaire included questions on heat stress experience in different contexts of daily life, health impacts of the heat, coping measures, housing conditions, urban environment, living conditions, and socio-demographic characteristics. The responses of the 323 survey participants living and working in Karlsruhe show that they on average experienced the heat as rather stressful event, whereby the heat stress experienced at home was significant lower than heat stress experienced at work or in general. Regression analyses show that, among the factors included in the questionnaire, the health impairments suffered during the heat, the control belief and the coping measures implemented mainly determine heat stress experienced in general and at work. For the subjective heat stress at home, factors of the built urban environment such as heat loading of district, living in the attic or the ground floor, and heat protection elements of the inhabited building also played a role. At the same time, the way the respondents used different coping strategies in context of their daily activities and routines during heat suggests lessons to learn from this event how individual response to heat differs from responses to other types of natural hazards.

Very High Resolution Solar X-ray Imaging Using Diffractive Optics

NASA Technical Reports Server (NTRS)

Dennis, B. R.; Skinner, G. K.; Li, M. J.; Shih, A. Y.

2012-01-01

This paper describes the development of X-ray diffractive optics for imaging solar flares with better than 0.1 arcsec angular resolution. X-ray images with this resolution of the greater than or equal to 10 MK plasma in solar active regions and solar flares would allow the cross-sectional area of magnetic loops to be resolved and the coronal flare energy release region itself to be probed. The objective of this work is to obtain X-ray images in the iron-line complex at 6.7 keV observed during solar flares with an angular resolution as fine as 0.1 arcsec - over an order of magnitude finer than is now possible. This line emission is from highly ionized iron atoms, primarily Fe xxv, in the hottest flare plasma at temperatures in excess of approximately equal to 10 MK. It provides information on the flare morphology, the iron abundance, and the distribution of the hot plasma. Studying how this plasma is heated to such high temperatures in such short times during solar flares is of critical importance in understanding these powerful transient events, one of the major objectives of solar physics.We describe the design, fabrication, and testing of phase zone plate X-ray lenses with focal lengths of approximately equal to 100 m at these energies that would be capable of achieving these objectives. We show how such lenses could be included on a two-spacecraft formation-flying mission with the lenses on the spacecraft closest to the Sun and an X-ray imaging array on the second spacecraft in the focal plane approximately equal to 100 m away. High resolution X-ray images could be obtained when the two spacecraft are aligned with the region of interest on the Sun. Requirements and constraints for the control of the two spacecraft are discussed together with the overall feasibility of such a formation-flying mission.

Estimating movement and survival rates of a small saltwater fish using autonomous antenna receiver arrays and passive integrated transponder tags

USGS Publications Warehouse

Rudershausen, Paul J.; Buckel, Jeffery A.; Dubreuil, Todd; O'Donnell, Matthew J.; Hightower, Joseph E.; Poland, Steven J.; Letcher, Benjamin H.

2014-01-01

We evaluated the performance of small (12.5 mm long) passive integrated transponder (PIT) tags and custom detection antennas for obtaining fine-scale movement and demographic data of mummichog Fundulus heteroclitus in a salt marsh creek. Apparent survival and detection probability were estimated using a Cormack Jolly Seber (CJS) model fitted to detection data collected by an array of 3 vertical antennas from November 2010 to March 2011 and by a single horizontal antenna from April to August 2011. Movement of mummichogs was monitored during the period when the array of vertical antennas was used. Antenna performance was examined in situ using tags placed in wooden dowels (drones) and in live mummichogs. Of the 44 tagged fish, 42 were resighted over the 9 mo monitoring period. The in situ detection probabilities of the drone and live mummichogs were high (~80-100%) when the ambient water depth was less than ~0.8 m. Upstream and downstream movement of mummichogs was related to hourly water depth and direction of tidal current in a way that maximized time periods over which mummichogs utilized the intertidal vegetated marsh. Apparent survival was lower during periods of colder water temperatures in December 2010 and early January 2011 (median estimate of daily apparent survival = 0.979) than during other periods of the study (median estimate of daily apparent survival = 0.992). During late fall and winter, temperature had a positive effect on the CJS detection probability of a tagged mummichog, likely due to greater fish activity over warmer periods. During the spring and summer, this pattern reversed possibly due to mummichogs having reduced activity during the hottest periods. This study demonstrates the utility of PIT tags and continuously operating autonomous detection systems for tracking fish at fine temporal scales, and improving estimates of demographic parameters in salt marsh creeks that are difficult or impractical to sample with active fishing gear.

Shingle System And Method

DOEpatents

Dinwoodie, Thomas L.

2005-04-26

A barrier, such as a PV module, is secured to a base by a support to create a shingle assembly with a venting region defined between the barrier and base for temperature regulation. The bottom edges of the barriers of one row may overlap the top edges of the barriers of another row. The shingle assemblies may be mounted by first mounting the bases to an inclined surface; the barriers may be then secured to the bases using the supports to create rows of shingle assemblies defining venting regions between the barriers and the bases for temperature regulation.

Planar solid oxide fuel cell with staged indirect-internal air and fuel preheating and reformation

DOEpatents

Geisbrecht, Rodney A; Williams, Mark C

2003-10-21

A solid oxide fuel cell arrangement and method of use that provides internal preheating of both fuel and air in order to maintain the optimum operating temperature for the production of energy. The internal preheat passes are created by the addition of two plates, one on either side of the bipolar plate, such that these plates create additional passes through the fuel cell. This internal preheat fuel cell configuration and method reduce the requirements for external heat exchanger units and air compressors. Air or fuel may be added to the fuel cell as required to maintain the optimum operating temperature through a cathode control valve or an anode control valve, respectively. A control loop comprises a temperature sensing means within the preheat air and fuel passes, a means to compare the measured temperature to a set point temperature and a determination based on the comparison as to whether the control valves should allow additional air or fuel into the preheat or bypass manifolds of the fuel cell.

The association between preceding drought occurrence and heat waves in the Mediterranean

NASA Astrophysics Data System (ADS)

Russo, Ana; Gouveia, Célia M.; Ramos, Alexandre M.; Páscoa, Patricia; Trigo, Ricardo M.

2017-04-01

A large number of weather driven extreme events has occurred worldwide in the last decade, namely in Europe that has been struck by record breaking extreme events with unprecedented socio-economic impacts, including the mega-heatwaves of 2003 in Europe and 2010 in Russia, and the large droughts in southwestern Europe in 2005 and 2012. The last IPCC report on extreme events points that a changing climate can lead to changes in the frequency, intensity, spatial extent, duration, and timing of weather and climate extremes. These, combined with larger exposure, can result in unprecedented risk to humans and ecosystems. In this context it is becoming increasingly relevant to improve the early identification and predictability of such events, as they negatively affect several socio-economic activities. Moreover, recent diagnostic and modelling experiments have confirmed that hot extremes are often preceded by surface moisture deficits in some regions throughout the world. In this study we analyze if the occurrence of hot extreme months is enhanced by the occurrence of preceding drought events throughout the Mediterranean area. In order to achieve this purpose, the number of hot days in the regions' hottest month will be associated with a drought indicator. The evolution and characterization of drought was analyzed using both the Standardized Precipitation Evaporation Index (SPEI) and the Standardized Precipitation Index (SPI), as obtained from CRU TS3.23 database for the period 1950-2014. We have used both SPI and SPEI for different time scales between 3 and 9 months with a spatial resolution of 0.5°. The number of hot days and nights per month (NHD and NHN) was determined using the ECAD-EOBS daily dataset for the same period and spatial resolution (dataset v14). The NHD and NHN were computed, respectively, as the number of days with a maximum or minimum temperature exceeding the 90th percentile. Results show that the most frequent hottest months for the Mediterranean region occur in July and August. Moreover, the magnitude of correlations between detrended NHD/NHN and the preceding 6- and 9-month SPEI/SPI are usually dimmer than for the 3 month time-scale. Most regions exhibit significantly negative correlations, i.e. high (low) NHD/NHN following negative (positive) SPEI/SPI values, and thus a potential for NHD/NHN early warning. Finally, correlations between the NHD/NHN with SPI and SPEI differ, with SPEI characterized by slightly higher values observed mainly for the 3-months time-scale. Acknowledgments: This work was partially supported by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project IMDROFLOOD (WaterJPI/0004/2014). Ana Russo thanks FCT for granted support (SFRH/BPD/99757/2014). A. M. Ramos was also supported by a FCT postdoctoral grant (FCT/DFRH/ SFRH/BPD/84328/2012).

Land of Three Suns (Artist's Concept Animation)

NASA Technical Reports Server (NTRS)

2005-01-01

[figure removed for brevity, see original site] Figure 1: Sifting the Light of Three Suns

This artist's animation shows the view from a hypothetical moon in orbit around the first known planet to reside in a tight-knit triple-star system. HD 188553 Ab is a gas giant planet, about 1.14 times the mass of Jupiter, with an orbital period of 3.3 days discovered using the Keck I telescope atop Mauna Kea in Hawaii, and zips around a single star that is orbited by a nearby pair of pirouetting stars. Because the stars in this triple system are bunched together, sunsets on the planet -- or on any moons that might exist around the planet -- would be spectacular. This rambunctious stellar family is called HD188753 and is located 149 light-years away in the constellation Cygnus.

In this movie, sunset is seen through the tenuous atmosphere of a hot, baked hypothetical moon. As the suns dip below the horizon, the gas giant comes into view. The moon's landscape remains illuminated by sunlight reflected off the planet. Both the planet and moon would be so hot that even in shadow their surfaces would glow.

The suns' colors and sizes reflect their masses, temperatures and distances to the planet. For example, the first star shown setting over the horizon is the closest, most massive and hottest of the trio, so it is depicted as large and white. The second star is farther away, less massive and cooler than the first, appearing smaller and yellow. The final star is at the same distance as the second, but it is still less massive and cooler, appearing even smaller and orange-red in color. Our Sun is a bit cooler than the hottest star of the system.

The graph in figure 1 shows the 'wobble' of a star being tugged on by the planet called HD 188753 Ab. The planet was discovered via the radial velocity technique, in which a planet's presence is inferred by the motion, or wobble, it causes in its parent star. Stellar motion is plotted here as changes in velocity (y-axis) versus time (x-axis).

Unlike most planetary wobbles, this one comes from a star that is circled by a nearby pair of stars. In other words, the planet orbits a single star that is part of a close-knit triple-star system. Because the starlight from this cramped bunch blends together, the task of sifting through the light to find the planet's signature was more difficult. This challenge was overcome with the help of detailed models of the triple-star system's light. Data from those models resulted in precise velocity measurements of the star circled by HD 188753 Ab.

Note: The size of the Full-Res TIFF for the still image is 3200 samples x 2400 lines.

Zinc, copper, and lead in mid-ocean ridge basalts and the source rock control on Zn/Pb in ocean-ridge hydrothermal deposits

USGS Publications Warehouse

Doe, B.R.

1994-01-01

The contents of Zn, Cu, and Pb in mid-ocean ridge basalts (MORB) and the MORB source-rock control on Zn/Pb in ocean-ridge hydrothermal deposits are examined. The values of Zn, Cu, and Pb for submarine mid-ocean ridge basalts (MORB) are, respectively (in ppm): average MORB-75, 75, and 0.7; West Valley, Juan de Fuca Ridge (JFR)-87, 64, and 0.5; southern JFR-120 and 0.5; and 21??N, East Pacific Rise (EPR)-73, 78, and 0.5. Values of Zn/Pb range from about 100-240 and Cu/ Pb from 100-156. In this study, Zn is found to correlate positively with TiO2 + FeO (mean square of weighted deviates, MSWD, of 1.6 for JFR basalt), and inversely with Mg number (MSWD of 3.5). Therefore, contrary to statements in the literature that Zn should be compatible in MORB, Zn is a mildly incompatible element and must be enriched in the glass phase relative to olivine as Zn does not fit into the other major phenocryst phase, plagioclase. In the source of MORB, Zn likely is most enriched in oxides: spinel, magnetite, and titanomagnetite. Copper generally does not correlate well with other elements in most MORB data examined. When differentiation is dominated by olivine, Cu has a tendency to behave incompatibly (e.g., at Mg numbers > 70), but, overall, Cu shows some tendency towards being a compatible element, particularly along the Mid-Atlantic Ridge, a behavior presumably due to separation of sulfides in which Cu (but not Zn) is markedly enriched. Copper thus may be in dispersed sulfides in the source of MORB. Ocean ridges provide important data on source-rock controls for sulfide deposits because, in sediment-starved ridges, much is known about the possible source rocks and mineralization is presently occurring. In contrast to Zn/Pb ~5 in continental hot Cl-rich brines, Zn/Pb in the hottest sediment-starved ridge black smoker hydrothermal fluids at 21 ??N, EPR is about 110, similar to local MORB (145), but Cu/Pb is closer to 30, possibly due to subsurface deposition of Cu. At the JFR, the best value of Zn/Pb in the hydrothermal fluids is about 175, again similar to local MORB (240), but Cu is very low in the fluids that are at temperatures less than 300??C. The large MORB-like Zn/Pb in the hottest black-smoker fluids suggests a source-rock control for the metals that prohibits significant galena in the black-smoker deposits of sediment-starved ridges. In contrast, exhalative deposits on sediment-swamped ridges have significant galena; its presence is suggestive of Pb derivation from sediments, an origin supported by Pb isotope studies of LeHuray and colleagues in 1988. ?? 1994.

The National Transonic Facility

NASA Technical Reports Server (NTRS)

Holmes, H. K.

1986-01-01

The National Transonic Facility, NTF, is a high Reynolds Number facility where the increase in Reynolds Number is obtained by operating at high pressures and low temperatures. Liquid nitrogen is allowed to vaporize, making gaseous nitrogen the test medium with temperatures extending down to approximately 100 degrees Kelvin. These factors have created unique, new challenges to those developing sensors and instrumentation. Pressure vessels, thermal enclosures or elaborate temperature compensations schemes, are needed for environmental protection and special materials are needed for sensors and model fabrication. The need for a new measurement, model deformation, was also created. An extensive program to develop the unique sensors and instrumentation was initiated. The data acquisition system and systems to measure aerodynamic forces and pressures, model attitude, and model deformation, are discussed.

Sound control by temperature gradients

NASA Astrophysics Data System (ADS)

Sánchez-Dehesa, José; Angelov, Mitko I.; Cervera, Francisco; Cai, Liang-Wu

2009-11-01

This work reports experiments showing that airborne sound propagation can be controlled by temperature gradients. A system of two heated tubes is here used to demonstrate the collimation and focusing of an ultrasonic beam by the refractive index profile created by the temperature gradients existing around the tubes. Numerical simulations supporting the experimental findings are also reported.

Alternative Fuels Data Center: Reliable Temperature Compensation is

Science.gov Websites

Technical Bulletin addresses the potential hazards created by failure of compressed natural gas (CNG ) dispensers that do not accurately compensate for the temperature of the natural gas in vehicle storage containers as they are filled and the history of serious incidents as a result. Accurate temperature

Greenhouse effect simulator - An educational application

NASA Astrophysics Data System (ADS)

Machado, Alan Freitas; Viveiros, Bruno Martins; da Silva, Claudio Elias

2016-12-01

Using the program "Modellus", we intend to create a simple simulation to show the impacts that the Greenhouse Effect might have, in a didactic and friendly way, in order to expose this notions to high and middle school students. In order to do so, we created a program that will simulate a sweep, through the Troposphere, and create two lines in a graphic, one showing the temperatures behavior, in normal conditions, and the other showing how the temperature behaves in the presence of excess of Greenhouse gases. The main purpose of the project is to use the model in schools and try to make kids more conscious of their roles in our so society, showing them the consequences of the tendency of our acts, stimulating them to be more proactives to change the future.

Preparation of pyrolysis reference samples: evaluation of a standard method using a tube furnace.

PubMed

Sandercock, P Mark L

2012-05-01

A new, simple method for the reproducible creation of pyrolysis products from different materials that may be found at a fire scene is described. A temperature programmable steady-state tube furnace was used to generate pyrolysis products from different substrates, including softwoods, paper, vinyl sheet flooring, and carpet. The temperature profile of the tube furnace was characterized, and the suitability of the method to reproducibly create pyrolysates similar to those found in real fire debris was assessed. The use of this method to create proficiency tests to realistically test an examiner's ability to interpret complex gas chromatograph-mass spectrometric fire debris data, and to create a library of pyrolsates generated from materials commonly found at a fire scene, is demonstrated. © 2011 American Academy of Forensic Sciences.

High Temperature Stable Nanocrystalline SiGe Thermoelectric Material

NASA Technical Reports Server (NTRS)

Yang, Sherwin (Inventor); Matejczyk, Daniel Edward (Inventor); Determan, William (Inventor)

2013-01-01

A method of forming a nanocomposite thermoelectric material having microstructural stability at temperatures greater than 1000 C. The method includes creating nanocrystalline powder by cryomilling. The method is particularly useful in forming SiGe alloy powder.

High Temperature Irradiation Resistant Thermocouple (HTIR-TC)

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

Rempe, Joy; Condie, Keith; Knudson, Darrell

2011-01-01

INL researchers have created a new thermocouple that can resist high temperature and radiation. This device will improve safety and reduce costs associated with unit failures. Learn more about INL research at http://www.facebook.com/idahonationallaboratory

High Temperature Irradiation Resistant Thermocouple (HTIR-TC)

ScienceCinema

Rempe, Joy; Condie, Keith; Knudson, Darrell

2018-05-16

INL researchers have created a new thermocouple that can resist high temperature and radiation. This device will improve safety and reduce costs associated with unit failures. Learn more about INL research at http://www.facebook.com/idahonationallaboratory

The International Treaty on Global Warming: Is it Good or Bad for the Economy?

NASA Astrophysics Data System (ADS)

Wei, Xinyu; Bao, Wenbin

2018-06-01

Global warming is one of the hottest topics all over the world. International authorities have worked together to negotiate the Paris Agreement on global warming. This Agreement has its supporters and critics. The key question is whether on balance is the Paris Assignment good or bad for the United States economy. This paper begins with some background information leading up to the passage of the treaty. Next, I outline what is in treaty. I then critically analyze the arguments in support of and against the Assignment. Finally, I explain the basis for my opinion that in the long run the treaty will benefit the United States economy.

Original structures, and fragmentation and reassembly histories of asteroids - Evidence from meteorites

NASA Technical Reports Server (NTRS)

Taylor, G. Jeffrey; Maggiore, Peter; Scott, Edward R. D.; Rubin, Alan E.; Keil, Klaus

1987-01-01

The validity of an onion shell model (OSM) for chondrite parent asteroids was assessed using metallographic cooling rates (MCR) derived from the compositions of metallic Fe-Ni grains. The hypothesis evaluated was that the hottest materials in chondrites would have been buried the deepest and cooled the slowest. The survey covered breccia from regolith and 13 different chondrites. The MCRs agreed well with cooling rates predicted by fission-track thermometry and Ar-40/Ar-39 ages. The OSM predicts an inverse correlation between the cooling rate and the petrographic type. Low correlations found between the MCRs and petrographic type indicate that chondrite parent asteroids were not assembled with onion shell structures.

The noise wars in helio- and asteroseismology

NASA Astrophysics Data System (ADS)

García, R. A.

2012-12-01

During this conference, latest results on helioseismology (both local and global) as well as in asteroseismology have been reviewed, the hottest questions discussed and the future prospects of our field fully debated. A conference so rich in the variety of topics addressed is impossible to be deeply reviewed in a paper. Therefore, I present here my particular view of the field as it is today, concentrating on the solar-like stars and global helioseismology. The link I found to do so is the constant battle in which we are all engaged against the sources of noise that difficult our studies. The noise in the data, the noise in the inversions, the precision and accuracy of our inferred models, \\ldots .

Meteorite WIS91600: A New Sample Related to a D- or T-type Asteroid

NASA Technical Reports Server (NTRS)

Hiroi, T.; Tonui, E.; Pieters, C. M.; Zolensky, M. E.; Ueda, Y.; Miyamoto, M.; Sasaki, S.

2005-01-01

Since the Tagish Lake meteorite fell in January 2000, the assumed one-of-the-kind meteorite has become the hottest issue among a diversity of scientists. Meanwhile, as the physical origin of the meteorite in our solar system, D or T asteroids have been suggested by Hiroi et al. based on comparison of their visible-near-infrared (VNIR) reflectance spectra. While it is probably still true that the Tagish Lake meteorite is possibly the first recovered sample from a D or T asteroid as a meteorite fall, we report in this paper that the meteorite WIS91600 may actually be the first recovered sample from one of those asteroids as a meteorite find.

Bluetooth: The invisible connector. Short-range wireless technology for the contemporary orthodontic practice.

PubMed

Mupparapu, Muralidhar

2007-06-01

Although it sounds like a nonvital tooth, Bluetooth is actually one of technology's hottest trends. It is an industrial specification for wireless personal area networks, but for a busy orthodontic practice, it translates to freedom from cables and cords. Despite its enigmatic name, Bluetooth-based devices and the wireless technology that these gadgets work with are here to stay. They promise to make life easier for the electronic-device users of all stripes, and orthodontists are no exception. The purpose of this article is to orient orthodontists, office staff, and auxiliary personnel to this universal wireless technology that is slowly becoming an integral part of every office.

The past and future of chemical information - A report of the Chemical Information Division Session of the 200th Meeting of the American Chemical Society

NASA Astrophysics Data System (ADS)

Tokizane, Soichi

At the historical meeting of the ACS CINF Division, the 1990 Herman Skolnik Award was presented to Dr. Ernst Meyer, who at BASF in Germany had developed a computer storage and retrieval system of chemical structures in 1960s. His and his colleagues' speeches in the award symposium were about the history of the development of chemical structure information in Germany. In the symposium of the Markush structure system, a hottest topic in this field, CAS's MARPAT and Markush-DARC co-developed by Questel, INPI, and Derwent were discussed by many papers. Other topics of this meeting were discussed, too.

Research on the architecture and key technologies of SIG

NASA Astrophysics Data System (ADS)

Fu, Zhongliang; Meng, Qingxiang; Huang, Yan; Liu, Shufan

2007-06-01

Along with the development of computer network, Grid has become one of the hottest issues of researches on sharing and cooperation of Internet resources throughout the world. This paper illustrates a new architecture of SIG-a five-hierarchy architecture (including Data Collecting Layer, Grid Layer, Service Layer, Application Layer and Client Layer) of SIG from the traditional three hierarchies (only including resource layer, service layer and client layer). In the paper, the author proposes a new mixed network mode of Spatial Information Grid which integrates CAG (Certificate Authority of Grid) and P2P (Peer to Peer) in the Grid Layer, besides, the author discusses some key technologies of SIG and analysis the functions of these key technologies.

VLTI + MIDI Study of the High Mass Protostellar Candidate NGC 3603 IRS 9A

NASA Astrophysics Data System (ADS)

Nürnberger, D. E. A.; Vehoff, S.; Hummel, C. A.; Duschl, W. J.

2010-02-01

The formation and early evolution of high mass stars is among the hottest topics in astrophysics. Interferometric studies of these young stars and their circumstellar environments (envelopes, disks and jets) at near and mid infrared wavelengths are still rare and in terms of data analysis/interpretation very challenging. We here report on observations of the high mass protostellar candidate NGC 3603 IRS 9A which we undertook with VLTI + MIDI in 2005, complemented by near and mid infrared imaging and spectroscopic data. We discuss our results obtained from dedicated modeling efforts, employing both DUSTY and MC3D radiative transfer codes for a selected number of source geometries and surface brightness distributions.

Strong stellar winds.

PubMed

Conti, P S; McCray, R

1980-04-04

The hottest and most luminous stars lose a substantial fraction of their mass in strong stellar winds. These winds not only affect the evolution of the star, they also carve huge expanding cavities in the surrounding interstellar medium, possibly affecting star formation. The winds are probably driven by radiation pressure, but uncertainties persist in their theoretical description. Strong x-ray sources associated with a few of these hot stars may be used to probe the stellar winds. The nature of the weak x-ray sources recently observed to be associated with many of these stars is uncertain. It is suggested that roughly 10 percent of the luminous hot stars may have as companions neutron stars or black holes orbiting within the stellar winds.

Tissue sparing surgery in knee reconstruction: unicompartmental (UKA), patellofemoral (PFA), UKA + PFA, bi-unicompartmental (Bi-UKA) arthroplasties

PubMed Central

Manzotti, A.; Montironi, F.; Pullen, C.

2008-01-01

Recently mini-invasive joint replacement has become one of the hottest topics in the orthopaedic world. However, these terms have been improperly misunderstood as a “key-hole” surgery where traditional components are implanted with shorter surgical approaches, with few benefits and several possible dangers. Small implants as unicompartmental knee prostheses, patellofemoral prostheses and bi-unicompartmental knee prostheses might represent real less invasive procedures: Tissue sparing surgery, the Italian way to minimally invasive surgery (MIS). According to their experience the authors go through this real tissue sparing surgery not limited only to a small incision, but where the surgeons can respect the physiological joint biomechanics. PMID:19384616

Modelling the Relationship Between Land Surface Temperature and Landscape Patterns of Land Use Land Cover Classification Using Multi Linear Regression Models

NASA Astrophysics Data System (ADS)

Bernales, A. M.; Antolihao, J. A.; Samonte, C.; Campomanes, F.; Rojas, R. J.; dela Serna, A. M.; Silapan, J.

2016-06-01

The threat of the ailments related to urbanization like heat stress is very prevalent. There are a lot of things that can be done to lessen the effect of urbanization to the surface temperature of the area like using green roofs or planting trees in the area. So land use really matters in both increasing and decreasing surface temperature. It is known that there is a relationship between land use land cover (LULC) and land surface temperature (LST). Quantifying this relationship in terms of a mathematical model is very important so as to provide a way to predict LST based on the LULC alone. This study aims to examine the relationship between LST and LULC as well as to create a model that can predict LST using class-level spatial metrics from LULC. LST was derived from a Landsat 8 image and LULC classification was derived from LiDAR and Orthophoto datasets. Class-level spatial metrics were created in FRAGSTATS with the LULC and LST as inputs and these metrics were analysed using a statistical framework. Multi linear regression was done to create models that would predict LST for each class and it was found that the spatial metric "Effective mesh size" was a top predictor for LST in 6 out of 7 classes. The model created can still be refined by adding a temporal aspect by analysing the LST of another farming period (for rural areas) and looking for common predictors between LSTs of these two different farming periods.

A theoretical study of the hydrogen-storage potential of (H2)4CH4 in metal organic framework materials and carbon nanotubes.

PubMed

Li, Q; Thonhauser, T

2012-10-24

The hydrogen-methane compound (H(2))(4)CH(4)-or for short H4M-is one of the most promising hydrogen-storage materials. This van der Waals compound is extremely rich in molecular hydrogen: 33.3 mass%, not including the hydrogen bound in CH(4); including it, we reach even 50.2 mass%. Unfortunately, H4M is not stable under ambient pressure and temperature, requiring either low temperature or high pressure. In this paper, we investigate the properties and structure of the molecular and crystalline forms of H4M, using ab initio methods based on van der Waals DFT (vdW-DF). We further investigate the possibility of creating the pressures required to stabilize H4M through external agents such as metal organic framework (MOF) materials and carbon nanotubes, with very encouraging results. In particular, we find that certain MOFs can create considerable pressure for H4M in their cavities, but not enough to stabilize it at room temperature, and moderate cooling is still necessary. On the other hand, we find that all the investigated carbon nanotubes can create the high pressures required for H4M to be stable at room temperature, with direct implications for new and exciting hydrogen-storage applications.

Nano-sized Superlattice Clusters Created by Oxygen Ordering in Mechanically Alloyed Fe Alloys

NASA Astrophysics Data System (ADS)

Hu, Yong-Jie; Li, Jing; Darling, Kristopher A.; Wang, William Y.; Vanleeuwen, Brian K.; Liu, Xuan L.; Kecskes, Laszlo J.; Dickey, Elizabeth C.; Liu, Zi-Kui

2015-07-01

Creating and maintaining precipitates coherent with the host matrix, under service conditions is one of the most effective approaches for successful development of alloys for high temperature applications; prominent examples include Ni- and Co-based superalloys and Al alloys. While ferritic alloys are among the most important structural engineering alloys in our society, no reliable coherent precipitates stable at high temperatures have been found for these alloys. Here we report discovery of a new, nano-sized superlattice (NSS) phase in ball-milled Fe alloys, which maintains coherency with the BCC matrix up to at least 913 °C. Different from other precipitates in ferritic alloys, this NSS phase is created by oxygen-ordering in the BCC Fe matrix. It is proposed that this phase has a chemistry of Fe3O and a D03 crystal structure and becomes more stable with the addition of Zr. These nano-sized coherent precipitates effectively double the strength of the BCC matrix above that provided by grain size reduction alone. This discovery provides a new opportunity for developing high-strength ferritic alloys for high temperature applications.

Molten salts and energy related materials.

PubMed

Fray, Derek

2016-08-15

Molten salts have been known for centuries and have been used for the extraction of aluminium for over one hundred years and as high temperature fluxes in metal processing. This and other molten salt routes have gradually become more energy efficient and less polluting, but there have been few major breakthroughs. This paper will explore some recent innovations that could lead to substantial reductions in the energy consumed in metal production and in carbon dioxide production. Another way that molten salts can contribute to an energy efficient world is by creating better high temperature fuel cells and novel high temperature batteries, or by acting as the medium that can create novel materials that can find applications in high energy batteries and other energy saving devices, such as capacitors. Carbonate melts can be used to absorb carbon dioxide, which can be converted into C, CO and carbon nanoparticles. Molten salts can also be used to create black silicon that can absorb more sunlight over a wider range of wavelengths. Overall, there are many opportunities to explore for molten salts to play in an efficient, low carbon world.

Increasing synchrony of high temperature and low flow in western North American streams: Double trouble for coldwater biota?

Treesearch

Ivan Arismendi; Mohammad Safeeq; Sherri L. Johnson; Jason B Dunham; Roy Haggerty

2013-01-01

Flow and temperature are strongly linked environmental factors driving ecosystem processes in streams. Stream temperature maxima (Tmax_w) and stream flow minima (Qmin) can create periods of stress for aquatic organisms. In mountainous areas, such as western North America, recent shifts toward an earlier spring peak flow and...

Nanoscale steady-state temperature gradients within polymer nanocomposites undergoing continuous-wave photothermal heating from gold nanorods.

PubMed

Maity, Somsubhra; Wu, Wei-Chen; Tracy, Joseph B; Clarke, Laura I; Bochinski, Jason R

2017-08-17

Anisotropically-shaped metal nanoparticles act as nanoscale heaters via excitation of a localized surface plasmon resonance, utilizing a photothermal effect which converts the optical energy into local heat. Steady-state temperatures within a polymer matrix embedded with gold nanorods undergoing photothermal heating using continuous-wave excitation are measured in the immediate spatial vicinity of the nanoparticle (referred to as the local temperature) from observing the rate of physical rotation of the asymmetric nanoparticles within the locally created polymer melt. Average temperatures across the entire (mostly solid) sample (referred to as the global temperature) are simultaneously observed using a fluorescence method from randomly dispersed molecular emitters. Comparing these two independent measurements in films having varying concentrations of nanorods reveals the interplay between the local and global temperatures, clearly demonstrating the capability of these material samples to sustain large steady-state spatial temperature gradients when experiencing continuous-wave excitation photothermal heating. These results are discussed quantitatively. Illustrative imaging studies of nanofibers under photothermal heating also support the presence of a large temperature gradient. Photothermal heating in this manner has potential utility in creating unique thermal processing conditions for outcomes such as driving chemical reactions, inducing crystallinity changes, or enhancing degradation processes in a manner unachievable by conventional heating methods.

EPR of radiation defects in lithium-oxyfluoride glass ceramics

NASA Astrophysics Data System (ADS)

Fedotovs, A.; Rogulis, U.; Sarakovskis, A.; Dimitrocenko, L.

2010-11-01

We studied oxyfluoride composites based on lithium silicate glasses with yttrium fluorides and rare-earth dopants. The electron paramagnetic resonance (EPR) has been used to obtain information about radiation induced defects in these materials. Spectra have been measured before and after X-ray irradiation at room temperature and at liquid nitrogen temperature. Fluoride crystallites within samples were created by means of thermal treatment at specific temperatures. EPR spectra of radiation induced defects in oxyfluoride glass ceramics, in which crystallites have not been yet created, show no explicit hfs interaction of fluorine nuclei. However, in glass ceramics, which already contains fluoride crystallites, the hfs characteristic to fluorine nuclei appears in the EPR spectra. EPR hyperfine structure could be explained within a model of an F-type centre in YF3 crystalline phase.

Overcharge and overdischarge protection of ambient temperature secondary lithium cells

NASA Technical Reports Server (NTRS)

Huang, Chen-Kuo (Inventor); Surampudi, Subbarao (Inventor); Attia, Alan I. (Inventor); Halpert, Gerald (Inventor)

1994-01-01

A cathode additive is provided for protecting an ambient temperature secondary lithium cell from overcharging or overdischarging. The cathode additive is chosen to create an upper voltage plateau which is slightly higher than a characteristic charge cutoff voltage of the cathode of the cell. The cathode additive additionally creates a lower voltage plateau which is slightly lower than the characteristic discharge cutoff voltage of the cell. Preferably, the cathode additive is a transition metal oxide or a sulfide and may, for example, include a mixture of Li2Mn2O4 and Li(0.1)MoO2.

Seeing Beyond the Monkey Head

NASA Image and Video Library

2015-08-20

Scores of baby stars shrouded by dust are revealed in this infrared image of the star-forming region NGC 2174, as seen by NASA Spitzer Space Telescope. Found in the constellation Orion, NGC 2174 is located around 6,400 light-years away. Some of the clouds in the region resemble the face of a monkey in visible-light images, hence the nebula's nickname: the "Monkey Head." However, in infrared images such as this, the monkey disappears. That's because different clouds are highlighted in infrared and visible-light images. Found in the northern reaches of the constellation Orion, NGC 2174 is located around 6,400 light-years away. Columns of dust, slightly to the right of center in the image, are being carved out of the dust by radiation and stellar winds from the hottest young stars recently born in the area. Spitzer's infrared view provides us with a preview of the next clusters of stars that will be born in the coming millennia. The reddish spots of light scattered through the darker filaments are infant stars swaddled by blankets of warm dust. The warm dust glows brightly at infrared wavelengths. Eventually, these stars will pop out of their dusty envelopes and their light will carve away at the dust clouds surrounding them. In this image, infrared wavelengths have been assigned visible colors we see with our eyes. Light with a wavelength of 3.5 microns is shown in blue, 8.0 microns is green, and 24 microns in red. The greens show the organic molecules in the dust clouds, illuminated by starlight. Reds are caused by the thermal radiation emitted from the very hottest areas of dust. Areas around the edges that were not observed by Spitzer have been filled in using infrared observations from NASA's Wide Field Infrared Survey Explorer, or WISE. http://photojournal.jpl.nasa.gov/catalog/PIA19836

High-temperature testing of glass/ceramic matrix composites

NASA Technical Reports Server (NTRS)

Mandell, John F.; Grande, Dodd H.; Dannemann, Kathryn A.

1989-01-01

Recent advances in ceramic and other high-temperature composites have created a need for test methods that can be used at 1000 C and above. Present test methods usually require adhesively bonded tabs that cannot be used at high temperatures. This paper discusses some of the difficulties with high-temperature test development and describes several promising test methods. Stress-strain data are given for Nicalon ceramic fiber reinforced glass and glass-ceramic matrix composites tested in air at temperatures up to 1000 C.

Systematics of first and second shape transition temperatures in heavy nuclei

NASA Astrophysics Data System (ADS)

Goodman, Alan L.; Jin, Taihao

1996-09-01

Thirty-one even-even isotopes (Z=72-80 and N=110-126) have two shape transition temperatures, where Tc2>~Tc1. For temperatures above Tc1, the equilibrium shape is spherical if the rotational frequency is zero. For these 31 nuclei, a slow rotation of the spherical shape creates a prolate shape rotating about its symmetry axis if the temperature is between Tc1 and Tc2, and an oblate shape rotating about its symmetry axis if the temperature is above Tc2.

Climate change - creating watershed resilience

USDA-ARS?s Scientific Manuscript database

Climate change is likely to intensify the circulation of water, which will shift spatial and temporal availability of snowmelt and runoff. In addition, drought and floods are likely to be more frequent, severe and widespread. Higher air temperatures will lead to higher ocean temperatures, elevating ...

The Effects of Commercial Cool Water Washing of Shell Eggs on Haugh Unit, Vitelline Membrane Strength, Aerobic Microorganisms and Fungi

USDA-ARS?s Scientific Manuscript database

Current egg washing practices utilize wash water temperatures averaging 49°C, and have been found to increase internal egg temperature by 6.7 to 7.8°C. These high temperatures create a more optimal environment for bacterial growth, including Salmonella Enteritidis (SE), if it is present. SE is the...