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1

Significant role of climatic trends on hydrothermal activity Coso Hot Springs, California  

SciTech Connect

The hydrothermal features of Coso Hot Springs have attracted visitors for 130 yr and scientific investigators for two decades. In 1978, anticipating effects of major geothermal developments nearby, the Naval Weapons Center (NWC) initiated a comprehensive monitoring program at a dozen hydrothermal sites in the Coso Hot Springs area. Nine years of monitoring preceded power production in the nearby Coso geothermal field in July 1987. During this period, steam was rising from numerous vents and gently boiling mud pots. Local rainfall caused increased boiling activity in several mud pots, with some overflowing during wet periods. Then in August 1988, a year after geothermal power production began major changes in hot spring activity commenced. Small mud pots and steamers started to grow and coalesce. In March 1989, mud-pot activity became more violent. Many buried wells failed causing surface activity in other areas to diminish. During ensuing months, large mud cones developed and much of the steam and boiling water occurred in a few major pots. Because the abrupt changes in hydrothermal activity followed so closely after nearby geothermal production began, the obvious cause has been attributed to geothermal developments. Studies of NWC baseline monitoring data indicate, however, that no effects of geothermal developments have been felt in the hot springs area. Rainfall and barometric effects account for most of the fluctuations in records of the past decade. Early accounts and field evidence suggest similar changes have occurred in the past.

Lofgren, B.E. (Benjamin E Lofgren and Associates, Sacramento, CA (USA))

1990-05-01

2

Coso Volcanic Field Tumulus  

USGS Multimedia Gallery

A tumulus in the Coso Volcanic Field, California. This lava was probably more viscous than the lava found in the Hawaii tumuli. Tumuli are structures usually associated with slow-moving flows. When the top of the flow crusts over, the lava beneath can well upward and create an elliptical, domed str...

3

Isotope Transport and Exchange within the Coso Geothermal System  

NASA Astrophysics Data System (ADS)

We are investigating the plumbing of the Coso geothermal system and the nearby Coso Hot Springs using finite element models of single-phase, variable-density fluid flow, conductive-convective heat transfer, fluid-rock isotope exchange, and groundwater residence times. Using detailed seismic reflection data and geologic mapping, we constructed a regional cross-sectional model that extends laterally from the Sierra Nevada to Wildhorse Mesa, west of the Argus Range. The base of the model terminates at the brittle-ductile transition zone. A sensitivity study was conducted using the model to explore the interaction between local and mountain front recharge, the effects of spatial variations in heat flow, and the role of permeable faults in controlling fluid circulation patterns. The model is constrained by present day bore hole temperature surveys, fluid inclusion temperatures, fluid-rock isotopic alteration patterns, and hot spring activity. While the results are non-unique, the analysis permits us to bracket the likely ranges of permeabilities and heat flow conditions that are consistent with observed data. Our findings suggest that active faults and seismogenic zones in and around the Coso geothermal area have much higher permeability and reactive surface areas than far field crustal rocks such as those in the Sierra Nevada. The Coso Wash fault zone must extend down to brittle- ductile transition zone depths of about 4 km in order for modeled results to match the observed hot spring activity.

Person, M.; Cohen, D.; Sabin, A.; Unruhn, J.; Gable, C.; Zyvoloski, G.; Monastero, F.

2006-12-01

4

Geologic Study of the Coso Formation  

SciTech Connect

There have been great advances in the last 20 years in understanding the volcanic, structural, geophysical, and petrologic development of the Coso Range and Coso geothermal field. These studies have provided a wealth of knowledge concerning the geology of the area, including general structural characteristics and kinematic history. One element missing from this dataset was an understanding of the sedimentology and stratigraphy of well-exposed Cenozoic sedimentary strata - the Coso Formation. A detailed sedimentation and tectonics study of the Coso Formation was undertaken to provide a more complete picture of the development of the Basin and Range province in this area. Detailed mapping and depositional analysis distinguishes separate northern and southern depocenters, each with its own accommodation and depositional history. While strata in both depocenters is disrupted by faults, these faults show modest displacement, and the intensity and magnitude of faulting does no t record significant extension. For this reason, the extension between the Sierran and Coso blocks is interpreted as minor in comparison to range bounding faults in adjacent areas of the Basin and Range.

D. L. Kamola; J. D. Walker

1999-12-01

5

Seismicity of the Coso Range, California  

SciTech Connect

A 16-station seismographic network, approximately 40 km north-south by 30 km east-west, was installed in the Coso Range, California, in September 1975 as part of a geological and geophysical assessment of the geothermal resource potential of range. During the first 2 years of network operations, 4216 local earthquakes (0.5< or =m< or =3.9) defined zones of seismicity that strike radially outward from a Pleistocene rhyolite field located near the center of the Coso Range. Most earthquakes were located in zones showing a general northwest trend across the range. Six earthquake swarms occurred within the area that includes the rhyolite field. Fault plane solutions show regional north-south compression: earthquakes located in northwest striking zones generally had right lateral strike slip focal mechanisms, those in northeast striking zones left lateral strike slip focal mechanisms, and those in north-south striking zones both normal and strike slip focal mechanisms. Earthquake depths showed little variation across the Coso Range; the depth distribution is similar to that of several carefully studied segments of the central San Andreas fault. The b value calculated for the entire range is 0.99 +- 0.08. The rhyolite field has a significantly higher b value of 1.26 +- 0.16; if only the shallow events (depth <5 km) are used in the calculation, the b value for this area becomes even higher, 1.34 +- 0.24. The higher b values were interpreted as reflecting the existence of short average fault lengths (<5 km) within the rhyolite field. The seismic data and other data suggest that the fault system lying between the rhyolite field and the adjacent Coso Basin is an important tectonic boundary. Present information is insufficient to determine the geothermal production capability of this fault system, but is does suggest that the system is a good target for further exploration.

Walter, A.W.; Weaver, C.S.

1980-05-10

6

The Coso Geothermal Area: A Laboratory for Advanced MEQ Studies  

E-print Network

- 1 - The Coso Geothermal Area: A Laboratory for Advanced MEQ Studies for Geothermal Monitoring-Dinger Geothermal Program Office, U. S. Navy, China Lake, CA 93555-6001 Keith.Richards-Dinge@navy.mil Keywords of three-component digital seismometers at the Coso geothermal area, California, supplemented by 14

Foulger, G. R.

7

Heat flow in the Coso Geothermal Area, Inyo County, California  

NASA Astrophysics Data System (ADS)

Obvious surface manifestations of an anomalous concentration of geothermal resources at the Coso geothermal area, Inyo County, California, include fumarolic activity and associated hydrothermally altered rocks. Pleistocene volcanic rocks associated with the geothermal activity include 38 rhyolite domes occupying a north trending structural and topographic ridge and numerous basaltic cinder cones and lava flows partly surrounding its southern half. In an investigation of the thermal regime of this Basin and Range geothermal area, temperature measurements were made in 25 shallow and 1 intermediate depth borehole. Geothermal gradients ranged from 25.3C/km to 906.C/km. The high gradients arise from convecting hot water and former convective transport of heat by dikes that fed the domes and flows. Thermal conductivity measurements were made on 312 samples from cores and drill cuttings. The resultant terrain-corrected heat flow values range from 1.6 to 23. HFU. The actual process by which heat is transferred is rather complex; however, the heat flow determinations can be divided into two groups. The first group, less than 4.0 HFU, are indicative of regions with primarily conductive regimes, although deep-seated mass transfer is implied. The second group, greater than 4.0 HFU, are characteristic of regions with considerable convective heat transfer in the shallow subsurface. The general shapes of the 3-and 5-HFU contours in the upper 35 m of the subsurface are essentially aligned with the major regional fault zones, suggesting that the high heat flows are the result of convective heat transfer caused by circulation of hot groundwater in these vertically permeable subsurface channels. The high heat flow values (>10 HFU) are essentially restricted to the rhyolite dome field and the associated surface thermal manifestations. Heat transferred by convection of water would be rapidly exhausted if it were not intermittently supplied with heat energy from depth; therefore the heat flow data substantiate the concept that the surface hydrothermal activity and associated volcanic rocks are products of a long-lived magmatic system that has periodically erupted lava during the past 0.3-1.0 m.y. This magmatic system is the crustal heat source for the present-day Coso geothermal system (1 HFU = 41.87 mW/m2).

Combs, Jim

1980-05-01

8

Microearthquake moment tensors from the Coso Geothermal area  

SciTech Connect

The Coso geothermal area, California, has produced hot water and steam for electricity generation for more than 20 years, during which time there has been a substantial amount of microearthquake activity in the area. Seismicity is monitored by a high-quality permanent network of 16 three-component digital borehole seismometers operated by the US Navy and supplemented by a ~ 14-station portable array of surface three-component digital instruments. The portable stations improve focal sphere coverage, providing seismic-wave polarity and amplitude data sets sufficient for determining full moment-tensor microearthquake mechanisms by the linearprogramming inversion method. We have developed a GUI-based interface to this inversion software that greatly increases its ease of use and makes feasible analyzing larger numbers of earthquakes than previously was practical. We show examples from an injection experiment conducted in well 34-9RD2, on the East Flank of the Coso geothermal area. This tight well was re-drilled February March 2005 with the intention of hydrofracturing it, but instead, pervasive porosity and fractures were encountered at about 2660 m depth. Total drilling mud losses occurred, obviating the need to stimulate the well. These mud losses induced a 50-minute swarm of 44 microearthquakes, with magnitudes in the range -0.3 to 2.6. Most of the largest microearthquakes occurred in the first 2 minutes. Accurate relative relocations and moment tensors for the best-recorded subset reveal fine details of the fracture that was stimulated. This comprised a fault striking at N 20 E and dipping at 75 to the WNW, which propagated to the NNE and upward. Co-injection focal mechanisms reveal combined crack-opening and shear motion. Stress release and mode of failure differed between the pre-, co- and post-swarm periods. Some post-swarm events involved cavity collapse, suggesting that some of the cavity opening caused by the fluid injection was quickly reversed. Stress & mode of failure had not returned to pre-swarm conditions within 1 month following the injection, posing the question of how long stress perturbations persist following a stimulation experiment. This question may be answered by processing data spanning a longer postinjection period, work that is currently underway and will be reported in this presentation.

Julian, B.R.; G.R. Foulger; F. Monastero

2007-04-01

9

A gravity model for the Coso geothermal area, California  

SciTech Connect

Two- and three-dimensional gravity modeling was done using gridded Bouguer gravity data covering a 45 {times} 45 km region over the Coso geothermal area in an effort to identify features related to the heat source and to seek possible evidence for an underlying magma chamber. Isostatic and terrain corrected Bouguer gravity data for about 1300 gravity stations were obtained from the US Geological Survey. After the data were checked, the gravity values were gridded at 1 km centers for the area of interest centered on the Coso volcanic field. Most of the gravity variations can be explained by two lithologic units: (1) low density wedges of Quarternary alluvium with interbedded thin basalts (2.4 g/cm{sup 3}) filling the Rose Valley and Coso Basin/Indian Wells Valley, and (2) low density cover of Tertiary volcanic rocks and intercalated Coso Formation (2.49 g/cm{sup 3}). A 3-D iterative approach was used to find the thicknesses of both units. The gravity anomaly remaining after effects from Units 1 and 2 are removed is a broad north-south-trending low whose major peak lies 5 km north of Sugarloaf Mountain, the largest of the less than 0.3 m.y. old rhyolite domes in the Coso Range. Most of this residual anomaly can be accounted for by a deep, low-density (2.47 g/cm{sup 3}) prismatic body extending from 8 to about 30 km below the surface. While some of this anomaly might be associated with fractured Sierran granitic rocks, its close correlation to a low-velocity zone with comparable geometry suggests that the residual anomaly is probably caused a large zone of partial melt underlying the rhyolite domes of the Coso Range. 12 refs., 9 figs.

Feighner, M.A.; Goldstein, N.E.

1990-08-01

10

published in JGR, 105, 21,781-21,794, 2000 Deformation and seismicity in the Coso geothermal  

E-print Network

published in JGR, 105, 21,781-21,794, 2000 Deformation and seismicity in the Coso geothermal area. Interferometric synthetic aperture radar (InSAR) data collected in the Coso geothermal area, eastern California with the production area of the Coso geothermal plant. The maximum subsidence rate in the peak of the anomaly is 3

11

Magmatic inclusions in rhyolites, contaminated basalts, and compositional zonation beneath the Coso volcanic field, California  

Microsoft Academic Search

Basaltic lava flows and high-silica rhyolite domes form the Pleistocene part of the Coso volcanic field in southeastern California. The distribution of vents maps the areal zonation inferred for the upper parts of the Coso magmatic system. Subalkalic basalts (2) were erupted well away from the rhyolite field at any given time. Compositional variation among these basalts can be ascribed

Charles R. Bacon; Jenny Metz

1984-01-01

12

Shear-wave splitting and reservoir crack characterization: the Coso geothermal eld  

Microsoft Academic Search

This paper aims to improve current understanding of the subsurface fracture system in the Coso geothermal field, located in east-central California. The Coso reservoir is in active economic development, so that knowledge of the subsurface fracture system is of vital importance for an accurate evaluation of its geothermal potential and day-to-day production. To detect the geometry and density of fracture

Gordana Vlahovic; Maya Elkibbi; J. A. Rial

2002-01-01

13

Shear-wave splitting and reservoir crack characterization: the Coso geothermal field  

Microsoft Academic Search

This paper aims to improve current understanding of the subsurface fracture system in the Coso geothermal field, located in east-central California. The Coso reservoir is in active economic development, so that knowledge of the subsurface fracture system is of vital importance for an accurate evaluation of its geothermal potential and day-to-day production. To detect the geometry and density of fracture

Gordana Vlahovic; Maya Elkibbi; J. A Rial

2003-01-01

14

Volatile compositions of melt inclusions in Coso Range Rhyolite  

SciTech Connect

Dissolved water and carbon dioxide concentrations were measured in melt inclusions in quartz phenocrysts from rhyolite domes and lava flows in the Coso volcanic field to determine pre-eruptive volatile content of the magma. Inclusions roughly 50--100 microns in diameter were analyzed for dissolved water and carbon dioxide using Fourier transform infrared spectroscopy (FTIR). The glasses have a total water concentration ranging from four to six weight percent and no detectable carbon dioxide. Vapor bubbles in the inclusions about 10--40 microns in diameter were also analyzed for their volatile composition. The spectra show no evidence for carbon dioxide, although significant water is observed. If the melt inclusions were saturated at the time of entrapment, then crystallization occurred between 1,200 and 2,100 bars pressure or greater than 4 kilometers depth.

Blouke, K.J. (Caltech, Pasadena, CA (United States))

1993-04-01

15

Microseismotectonics of the Coso Volcanic Field, Eastern California  

NASA Astrophysics Data System (ADS)

The near ubiquitous occurrence of microearthquakes and hydrothermal activity is fortunate because it serves to highlight the principles and practices of seismotectonics in the Coso Volcanic Field, Eastern California. Seismotectonics is the analysis of crustal deformation with the locations and mechanisms of the earthquakes it produces. Earthquakes are extremely sensitive indicators of the state of stress, because they occur on hydraulically conductive faults that are optimally oriented for failure. The microearthquake kinematics are determined with respect to the state of stress and provide the the basis of the seismotectonic interpretation. The seismotectonic investigation is facilitated with a new stress inversion technique. The state of stress is constrained with a triaxial representation of the Coulomb-Navier failure criterion. The failure criterion and the state of stress are used to distinguish the fault kinematics from the earthquake focal mechanisms. Evaluation of the Coulomb-Navier failure conditions requires a knowledge of the absolute magnitudes of tectonic stress. The absolute stress magnitudes are constrained by a relationship between the depth of the earthquake the state of stress. The first part of the dissertation is devoted to obtaining accurate earthquake locations to properly estimate of the hypocentral depth. A new earthquake location algorithm is developed to account for the strong geological and geophysical constraints placed on the velocity structure. In the second part, the focal mechanisms are calculated with respect to the constraints on the velocity model and are input into the new stress inversion technique. The microearthquake kinematics are highly consistent with shear failure and provide an important verification of seismotectonic tenets. The resulting state of crustal stress and strain are consistent with the combined influence of Basin-and-Range style extension and of distributed right-lateral shearing of the Pacific-North American plate interactions. The structures hosting the hydrothermal activity at Coso are inherently related to the regional style of deformation.

Lakings, James Duane

16

Late Cenozoic volcanism, geochronology, and structure of the Coso Range, Inyo County, California  

SciTech Connect

The Coso Range lies at the west edge of the Great Basin, adjacent to the southern part of the Sierra Nevada. A basement complex of pre-Cenozoic plutonic and metamorphic rocks is partly buried by approx.35 km/sup 3/ of late Cenozoic volcanic rocks that were erupted during two periods, as defined by K-Ar dating: (1) 4.0--2.5 m.y., approx.31 km/sup 3/ of basalt, rhyodacite, dacite, andesite, and rhyolite, in descending order of abundance, and (2) < or =1.1 m.y., nearly equal amounts of basalt and rhyolite, most of the rhyolite being < or =0.3 m.y. old. Vents for the volcanic rocks of the younger period are localized on and near a horst of basement rocks within a concavity defined by the distribution of vents of the older period. The alignment of many vents and the presence of a considerable number of roughly north-trending normal faults of late Cenozoic age reflect basin and range tectonics dominated by roughly east-west lithospheric extension. Fumaroles, intermittently active thermal springs, and associated altered rocks occur within and immediately east of the central part of the field of Quaternary rhyolite, in an area characterized by various geophysical anomalies that are evidently related to an active hot-water geothermal system. This system apparently is heated by a reservoir of silicic magma at > or =8-km depth, itself produced and sustained through partial melting of crustal rocks by thermal energy contained in mantle-derived basaltic magma that intrudes the crust in repsonse to lithospheric extension.

Duffield, W.A.; Bacon, C.R.; Dalrymple, G.B.

1980-05-10

17

Magmatic Evolution of the Coso Geothermal Area, California  

NASA Astrophysics Data System (ADS)

Geothermal energy in the Coso field owes its origin to basaltic magmatism. Volcanism commenced ~3.5 Ma ago, coincident with a widespread Pliocene outburst in eastern California. Although most basalts associated with this event are highly potassic, those at Coso are not. Pliocene volcanic rocks at Coso (erupted between 3.5-2 Ma) range from basalt to rhyodacite, show abundant petrographic evidence for open-system behavior (e.g., quartz xenocrysts in basalts), and have compositions consistent with mixing. In contrast, Pleistocene rocks, erupted <1 Ma ago, comprise a strongly bimodal suite of mildly alkalic basalt and high-silica rhyolite. Pleistocene basalts differ from their Pliocene counterparts in generally having more depleted 87Sr/86Sr and ?Nd values (0.703, +7 vs. 0.704, +4); higher TiO2 and Nb; lower MgO; greater stalling depths in the crust. Pliocene rocks are distinctly arc-like even though they were erupted ~10 Ma after subduction ceased. In contrast, Pleistocene basalts have a distinctly OIB-like geochemical signature, with undepleted high field strength elements and plume-like radiogenic isotope ratios; these characteristics are shared with late Cenozoic basalts across the western U.S. Rare Pleistocene basalts that were erupted from within the footprint of the rhyolite field have notably high TiO2 contents (>3 wt%), similar to basalts from the Columbia River and Snake River Plain fields. Unlike Pliocene rocks, which scatter toward isotopic values of local basement with increasing SiO2, Pleistocene rhyolites generally have high and consistent ?Nd (+1 - +2.5). Producing this signature by AFC processes involving basalt and basement rocks requires remarkably consistent mixing and fractionation at small-volume volcanic centers separated by several km. Alternatively, high ?Nd values in the rhyolites could have been produced by partial melting of Pliocene basalts and andesites, which have very similar Nd isotopic compositions. Increasing ?Nd in silicic rocks as the geothermal production area is approached suggests that the magmatic flux is highest there even though erupted volumes are significantly larger outside the geothermal area. One scenario consistent with the above data is as follows. Post-subduction tectonic events triggered magmatism at 3.5 Ma, tapping fertile, subduction-metasomatized lithospheric mantle. Basalts stalled in and partially melted the mid-crust, generating a mixed-magma series and copious volcanism. Depletion of the mantle source by 2 Ma led to a hiatus in magmatism. A change in basalt chemistry to OIB- affinity in the last 1 Ma suggests a profound change in magma source - likely involving decompression melting of ascending asthenospheric mantle, perhaps related to lithosphere delamination. Injection of such magmas into the lower crust, would have generated rhyolites by remelting of earlier emplaced mafic bodies - imparting a juvenile isotopic signature in the late rhyolites. Precursory Pliocene magmatism is a common feature of other western U.S. geothermal areas, including Twin Peaks, The Geysers, and Long Valley.

Glazner, A. F.; Miller, J. S.; Leeman, W. P.; Johnson, B. R.; Monastero, F. C.

2007-12-01

18

Attenuation and source properties at the Coso Geothermal area, California  

USGS Publications Warehouse

We use a multiple-empirical Green's function method to determine source properties of small (M -0.4 to 1.3) earthquakes and P- and S-wave attenuation at the Coso Geothermal Field, California. Source properties of a previously identified set of clustered events from the Coso geothermal region are first analyzed using an empirical Green's function (EGF) method. Stress-drop values of at least 0.5-1 MPa are inferred for all of the events; in many cases, the corner frequency is outside the usable bandwidth, and the stress drop can only be constrained as being higher than 3 MPa. P- and S-wave stress-drop estimates are identical to the resolution limits of the data. These results are indistinguishable from numerous EGF studies of M 2-5 earthquakes, suggesting a similarity in rupture processes that extends to events that are both tiny and induced, providing further support for Byerlee's Law. Whole-path Q estimates for P and S waves are determined using the multiple-empirical Green's function (MEGF) method of Hough (1997), whereby spectra from clusters of colocated events at a given station are inverted for a single attenuation parameter, ??, with source parameters constrained from EGF analysis. The ?? estimates, which we infer to be resolved to within 0.01 sec or better, exhibit almost as much scatter as a function of hypocentral distance as do values from previous single-spectrum studies for which much higher uncertainties in individual ?? estimates are expected. The variability in ?? estimates determined here therefore suggests real lateral variability in Q structure. Although the ray-path coverage is too sparse to yield a complete three-dimensional attenuation tomographic image, we invert the inferred ?? value for three-dimensional structure using a damped least-squares method, and the results do reveal significant lateral variability in Q structure. The inferred attenuation variability corresponds to the heat-flow variations within the geothermal region. A central low-Q region corresponds well with the central high-heat flow region; additional detailed structure is also suggested.

Hough, S.E.; Lees, J.M.; Monastero, F.

1999-01-01

19

Variations in dissolved gas compositions of reservoir fluids from the Coso geothermal field  

SciTech Connect

Gas concentrations and ratios in 110 analyses of geothermal fluids from 47 wells in the Coso geothermal system illustrate the complexity of this two-phase reservoir in its natural state. Two geographically distinct regions of single-phase (liquid) reservoir are present and possess distinctive gas and liquid compositions. Relationships in soluble and insoluble gases preclude derivation of these waters from a common parent by boiling or condensation alone. These two regions may represent two limbs of fluid migration away from an area of two-phase upwelling. During migration, the upwelling fluids mix with chemically evolved waters of moderately dissimilar composition. CO{sub 2} rich fluids found in the limb in the southeastern portion of the Coso field are chemically distinct from liquids in the northern limb of the field. Steam-rich portions of the reservoir also indicate distinctive gas compositions. Steam sampled from wells in the central and southwestern Coso reservoir is unusually enriched in both H{sub 2}S and H{sub 2}. Such a large enrichment in both a soluble and insoluble gas cannot be produced by boiling of any liquid yet observed in single-phase portions of the field. In accord with an upflow-lateral mixing model for the Coso field, at least three end-member thermal fluids having distinct gas and liquid compositions appear to have interacted (through mixing, boiling and steam migration) to produce the observed natural state of the reservoir.

Williams, Alan E.; Copp, John F.

1991-01-01

20

Are obsidian subsources meaningful units of analysis?: temporal and spatial patterning of subsources in the Coso Volcanic Field,  

E-print Network

Are obsidian subsources meaningful units of analysis?: temporal and spatial patterning Archaeologists frequently assign artifacts to chemically discrete subsignatures of major obsidian sources. While reserved. Keywords: Obsidian fingerprinting; Intra-source variability; Coso Volcanic Field; California

21

Time lapse gravity monitoring at Coso geothermal field  

NASA Astrophysics Data System (ADS)

An extensive time lapse gravity data set was acquired over the Coso geothermal field near Ridgecrest, California starting in 1987, with the latest data set acquired in 2013. In this thesis I use these gravity data to obtain a better understanding of mass changes occurring within the geothermal field. Geothermal energy is produced by flashing naturally heated ground water into steam which is used to turn turbines. Brine and re-condensed steam are then re-injected into the reservoir. A percentage of the water removed from the system is lost to the process. The time lapse gravity method consists of gravity measurements taken at the same locations over time, capturing snap shots of the changing field. After careful processing, the final data are differenced to extract the change in gravity over time. This change in gravity can then be inverted to recover the change in density and therefore mass over time. The inversion process also produces information on the three dimensional locations of these mass changes. Thirty five gravity data sets were processed and a subsection were inverted with two different starting times, a sixteen point data set collected continuously between 1991 and 2005, and a thirty-eight point data set collected between 1996 and 2005. The maximum change in gravity in the 1991 data group was -350 microGal observed near station CSE2. For the 1996 data group the maximum gravity change observed over the nine year period was -248 microGal. The gravity data were then inverted using the surface inversion method. Three values of density contrast were used, -0.05 g/cm3, -0.10 g/cm3, and -0.20 g/cm3. The starting surface in 1991 was set to 2,500 ft above sea level. The changes in surfaces were then converted to mass changes. The largest total mass change recovered was -1.39x1011 kg. This mass value is of the same order of magnitude as published well production data for the field. Additionally, the gravity data produces a better understanding of the spatial distribution of mass loss. The mass loss is concentrated in one area of the field while others remain somewhat constant.

Woolf, Rachel Vest

22

Hot Sauce Hot Spots  

NSDL National Science Digital Library

In this activity, learners model hot spot island formation, orientation and progression with condiments. Learners squirt a thick condiment sauce on a coarsely woven fabric to model how volcanic island hot spots form.

Muller, Eric

2007-01-01

23

Teleseismic evidence for a low-velocity body under the Coso geothermal area  

Microsoft Academic Search

Teleseismic P wave arrivals were recorded by a dense array of seismograph stations located in the Coso geothermal area, California. The resulting pattern of relative residuals an area showing approximately 0.2-s excess travel time that migrates with changing source azimuth, suggesting that the area is the 'delay shadow' produced by a deep, low-velocity body. Inversion of the relative residual data

P. Reasenberg; W. Ellisworth; A. Walter

1980-01-01

24

36Cl/Cl ratios in geothermal systems: preliminary measurements from the Coso Field  

SciTech Connect

The {sub 36}Cl/Cl isotopic composition of chlorine in geothermal systems can be a useful diagnostic tool in characterizing hydrologic structure, in determining the origins and age of waters within the systems, and in differentiating the sources of chlorine (and other solutes) in the thermal waters. The {sub 36}Cl/Cl values for several geothermal water samples and reservoir host rock samples from the Coso, California geothermal field have been measured for these purposes. The results indicate that most of the chlorine is not derived from the dominant granitoid that host the geothermal system. If the chlorine was originally input into the Coso subsurface through meteoric recharge, that input occurred at least 1-1.25 million years ago. The results suggest that the thermal waters could be connate waters derived from sedimentary formations, presumably underlying and adjacent top the granitic rocks, which have recently migrated into the host rocks. Alternatively, most of the chlorine but not the water, may have recently input into the system from magmatic sources. In either case, the results indicate that most of the chlorine in the thermal waters has existed within the granitoid host rocks for no more than about 100,00-200,00 years. this residence time for the chlorine is similar to residence times suggested by other researchers for chlorine in deep groundwaters of the Mono Basin north of the Coso field.

Nimz, G.J.; Moore, J.N.; Kasameyer, P.W.

1997-07-01

25

Pleistocene high-silica rhyolites of the Coso volcanic field, Inyo County, California.  

USGS Publications Warehouse

The high-silica rhyolite domes and lava flows of the bimodal Pleistocene part of the Coso volcanic field provide an example of the early stages of evolution of a silicic magmatic system of substantial size and longevity. Major and trace element compositions are consistent with derivation from somewhat less silicic parental material by liquid state differentiation processes in compositionally and thermally zoned magmatic systems. Seven chemically homogeneous eruptive groups can be distinguished on the basis of trace element and K/Ar data. The oldest two groups are volumetrically minor and geochemically distinct from the younger groups, all five of which appear to have evolved from the same magmatic system. Erupted volume-time relations suggest that small amounts of magma were bled from the top of a silicic reservoir at a nearly constant long-term rate over the last 0.24Ma. The interval of repose between eruptions appears to be proportional to the volume of the preceding eruptive group. This relationship suggests that eruptions take place when some parameter which increases at a constant rate reaches a critical value; this parameter may be extensional strain accumulated in roof rocks. Extension of the lithosphere favors intrusion of basalt into the crust, attendant partial melting, and maintenance of a long-lived silicic magmatic system. The Coso silicic system may contain a few hundred cubic kilometers of magma. The Coso magmatic system may eventually have the potential for producing voluminous pyroclastic eruptions if the safety valve provided by rapid crustal extension becomes inadequate to 1) defuse the system through episodic removal of volatile-rich magma from its top and 2) prohibit migration of the reservoir to a shallow crustal level.-from Authors

Bacon, C.R.; Macdonald, R.; Smith, R.L.; Baedecker, P.A.

1981-01-01

26

Magmatic inclusions in rhyolites, contaminated basalts, and compositional zonation beneath the Coso volcanic field, California  

USGS Publications Warehouse

Basaltic lava flows and high-silica rhyolite domes form the Pleistocene part of the Coso volcanic field in southeastern California. The distribution of vents maps the areal zonation inferred for the upper parts of the Coso magmatic system. Subalkalic basalts (<50% SiO2) were erupted well away from the rhyolite field at any given time. Compositional variation among these basalts can be ascribed to crystal fractionation. Erupted volumes of these basalts decrease with increasing differentiation. Mafic lavas containing up to 58% SiO2, erupted adjacent to the rhyolite field, formed by mixing of basaltic and silicic magma. Basaltic magma interacted with crustal rocks to form other SiO2-rich mafic lavas erupted near the Sierra Nevada fault zone. Several rhyolite domes in the Coso volcanic field contain sparse andesitic inclusions (55-61% SiO2). Pillow-like forms, intricate commingling and local diffusive mixing of andesite and rhyolite at contacts, concentric vesicle distribution, and crystal morphologies indicative of undercooling show that inclusions were incorporated in their rhyolitic hosts as blobs of magma. Inclusions were probably dispersed throughout small volumes of rhyolitic magma by convective (mechanical) mixing. Inclusion magma was formed by mixing (hybridization) at the interface between basaltic and rhyolitic magmas that coexisted in vertically zoned igneous systems. Relict phenocrysts and the bulk compositions of inclusions suggest that silicic endmembers were less differentiated than erupted high-silica rhyolite. Changes in inferred endmembers of magma mixtures with time suggest that the steepness of chemical gradients near the silicic/mafic interface in the zoned reservoir may have decreased as the system matured, although a high-silica rhyolitic cap persisted. The Coso example is an extreme case of large thermal and compositional contrast between inclusion and host magmas; lesser differences between intermediate composition magmas and inclusions lead to undercooling phenomena that suggest smaller ??T. Vertical compositional zonation in magma chambers has been documented through study of products of voluminous pyroclastic eruptions. Magmatic inclusions in volcanic rocks provide evidence for compositional zonation and mixing processes in igneous systems when only lava is erupted. ?? 1984 Springer-Verlag.

Bacon, C.R.; Metz, J.

1984-01-01

27

Hot Science: Hot rocks  

NSDL National Science Digital Library

This site explores two kinds of igneous rock, pumice and granite. Pumice is an example of extrusive igneous rock, while granite is an example of intrusive igneous rock. Intrusive indicates that the magma was forced close to the surface, but then cooled more slowly underneath the surface. The question, "How hot is Lava?" is linked to an explanation of the heat of lava, why it must be sampled when it is very hot, and how the samples are taken.

28

S-wave Anisotropy and Crack Distribution at the Coso Geothermal Field, California  

NASA Astrophysics Data System (ADS)

The Coso geothermal area is located along the eastern front of Sierra Nevada, in the southwestern Basin and Range Province. Seismic activity averaging more than 20 microearthquakes per day is the result of both regional tectonics and geothermal production activity [Malin, 1994]. Microseismicity is monitored by the Coso Digital Downhole Seismic Network (CDDSN) recording at 2 ms sampling rate. Continuous operation of the CDDSN since 1990 created a data set of exceptional richness and continuity. We used data accumulated from January 1999 through June 2000 for the study of S wave anisotropy and crack distribution. Understanding the faults and associated fracture system in Coso is fundamental for efficient long-term energy extraction and micro-tectonic models of the area. Strike of cracks in the shear-wave window of each station was determined by plotting rose diagrams of the fast shear-wave polarization directions. Each rose diagram has a clear dominant polarization direction, interpreted as the direction of the local fracture system. Three dominant strike groups were observed: 0 - 20 NE, 40 - 60 NE and 20 - 40 NW. These results are consistent with subsurface crack directions determined by Lou and Rial [1997], and with photographically and magnetically mapped alignments on the surface [Moore and Erskine, 1990], as well as with deep borehole observations. Four stations centered in the geothermal production area were selected for detailed study of variation of arrival time delays between fast and slow shear-waves and changes of polarization of leading shear-wave with time. Preliminary results suggest that for one station in the northeast end of the geothermal field, there is an increase in number of secondary fractures with strike from 10 NW to 30 NE in the data from January to June of 2000, relative to data from January to June of 1999. Statistical significance and reasons for such a change will be further studied, although it is interesting to note that this station is closer than any other in the CDDSN to the production well. Lou, M. and J. A. Rial, Geophysics, 62, 487-494, (1997). Malin, P. E., Transactions of the Geothermal Research Council, 18, 17-22, (1994). Moore, J. N. and M. C. Erskine, Am. Assn. Petr. Geol. EMD 1, 41-61, (1990).

Vlahovic, G.; Elkibbi, M.; Rial, J. A.

2001-05-01

29

Deformation of poorly consolidated sediment during shallow emplacement of a basalt sill, Coso Range, California  

USGS Publications Warehouse

A 150-m-long, wedge-shaped unit of folded and faulted marly siltstone crops out between undeformed sedimentary rocks on the north flank of the Coso Range, California. The several-meter-thick blunt end of this wedge abuts the north margin of a basaltic sill of comparable thickness. Chaotically deformed siltstone crops out locally at the margin of this sill, and at one locality breccia pipes about one meter in diameter crosscut the sill. The sill extends about 1 km south up the paleoslope, where it merges through continuous outcrop with a lava flow that in turn extends 1.4 km to a vent area marked by more than 100 m of agglutinate and scoria. Apparently, lava extruded at this vent flowed onto unconsolidated sediments, burrowed into them, and fed a sill at about 40 m depth within the sedimentary sequence. The sill initially propagated by wedging between sedimentary beds, but eventually began to push some beds ahead of itself, forming a remarkable train of folds in the process. The sediments apparently were wet at the time of sill emplacement, because hydrothermal alteration is common near the contact between the two rock types and because the breccia pipes that crosscut the sill apparently resulted from phreatic explosions of pore water heated at the base of the cooling sill. Comparison of deformation of the host material at the Coso locality with that reportedly caused by emplacement of sills elsewhere indicates that the character of deformation differs greatly among the various localities. The specific response of host material depends upon such parameters as initial properties of magma and host material, rate of sill growth and attendant rate of strain of host material, and depth of sill emplacement. Some properties may change considerably during an intrusive-deformational episode, thus complicating accurate reconstruction of such an event. ?? 1986 Springer-Verlag.

Duffield, W.A.; Bacon, C.R.; Delaney, P.T.

1986-01-01

30

Residence, resorption and recycling of zircons in Devils Kitchen rhyolite, Coso Volcanic Field, California  

USGS Publications Warehouse

Zircons from the Devils Kitchen rhyolite in the Pleistocene Coso Volcanic field, California have been analyzed by in situ Pb/U ion microprobe (SHRIMP-RG) and by detailed cathodoluminescence imaging. The zircons yield common-Pb-corrected and disequilibrium-corrected 206Pb/238U ages that predate a previously reported K-Ar sanidine age by up to 200 kyr, and the range of ages exhibited by the zircons is also approximately 200 kyr. Cathodoluminescence imaging indicates that zircons formed in contrasting environments. Most zircons are euhedral, and a majority of the zircons are weakly zoned, but many also have anhedral, embayed cores, with euhedral overgrowths and multiple internal surfaces that are truncated by later crystal zones. Concentrations of U and Th vary by two orders of magnitude within the zircon population, and by 10-20 times between zones within some zircon crystals, indicating that zircons were transferred between contrasting chemical environments. A zircon saturation temperature of ???750??C overlaps within error a previously reported phenocryst equilibration temperature of 740 ?? 25??C. Textures in zircons indicative of repeated dissolution and subsequent regrowth are probably caused by punctuated heating by mafic magma input into rhyolite. The overall span of ages and large variation in U and Th concentrations, combined with calculated zircon saturation temperatures and resorption times, are most compatible with crystallization in magma bodies that were emplaced piecemeal in the crust at Coso over 200 kyr prior to eruption, and that were periodically rejuvenated or melted by subsequent basaltic injections. ?? Oxford University Press 2004; all rights reserved.

Miller, J.S.; Wooden, J.L.

2004-01-01

31

Fault rock mineralogy and fluid flow in the Coso Geothermal Field, CA  

NASA Astrophysics Data System (ADS)

The minerals that comprise fault rock, their grain shapes, and packing geometry are important controls on fault zone properties such as permeability, frictional strength, and slip behavior. In this study we examine the role of mineralogy and deformation microstructures on fluid flow in a fault-hosted, fracture-dominated geothermal system contained in granitic rocks in the Coso Geothermal Field, CA. Initial examination of the mineralogy and microstructure of fault rock obtained from core and surface outcrops reveals three fault rock types. (1) Fault rock consisting of kaolinite and amorphous silica that contains large connected pores, dilatant brittle fractures, and dissolution textures. (2) Fault rock consisting of foliated layers of chlorite and illite-smectite separated by slip surfaces. (3) Fault rock consisting of poorly sorted angular grains, characterized by large variations in grain packing (pore size), and crack-seal textures. These different fault rocks are respectively associated with a high permeability upper boiling zone for the geothermal system, a conductively heated "caprock" at moderate to shallow depth associated with low permeability, and a deeper convectively heated region associated with enhanced permeability. Outcrop and hand-sample scale mapping, XRD analysis, and SEM secondary electron images of fault gouge and slip surfaces at different stages of development (estimated shear strain) are used to investigate the processes responsible for the development and physical properties of these distinct fault rocks. In each type of fault rock, mineral dissolution and re-precipitation in conjunction with the amount and geometry of porosity changes induced by dilation or compaction are the key controls on fault rock development. In addition, at the contacts between slip surfaces, abrasion and resulting comminution appear to influence grain size, sorting, and packing. Macroscopically, we expect the frictional strength of these characteristic fault rocks to differ because the processes that accommodate deformation depend strongly on mineralogy. Frictional strength of quartz-dominated fault rocks in the near surface and in the reservoir should be greater (~0.6) than that in the clay-dominated cap rock (~0.2-0.4). Similarly, permeability should be much lower in foliated clay-rich fault rocks than in quartz-rich fault rocks as evidenced by larger, more connected pores imaged in quartz-rich gouge. Mineral stability is a function of loading, strain rate, temperature, and fluid flow conditions. Which minerals form, and the rates at which they grow is also a key element in determining variations in the magnitude and anisotropy of fault zone properties at Coso. Consequently, we suggest that the development of fault-zone properties depends on the feedback between deformation, resulting changes in permeability, and large-scale fluid flow and the leading to dissolution/precipitation of minerals in the fault rock and adjacent host rock. The implication for Coso is that chemical alteration of otherwise low-porosity crystalline rocks appears to determine the distribution and temporal evolution of permeability in the actively deforming fracture network at small to moderate scales as well as along major, reservoir-penetrating fault zones.

Davatzes, N. C.; Hickman, S. H.

2005-12-01

32

Dynamic triggering of microearthquakes in the Long Valley Caldera and Coso Geothermal Field  

NASA Astrophysics Data System (ADS)

Recent studies have shown that microearthquakes can be dynamically triggered by the passing of surface waves from regional and teleseismic events. However, the underlying physical mechanisms and the necessary conditions that favor dynamic triggering are still in debate. Here we conduct a systematic search of dynamically triggered microearthquakes around the Long Valley Caldera (LVC) and Coso Geothermal Field (CGF) in California. In each region, we select distant mainshocks in 1999-2010 with M>=7.5 over 1000 km away, or M>=5.5 between 100-2500 km. Next, we apply 2-8 or 2-16 Hz band-pass-filtered data to the three-component seismograms recorded at each region, and identify triggered events as high-frequency seismic energy during large-amplitude surface waves of regional and teleseismic events. We calculate the beta statistic values based on events listed in the local earthquake catalogs and hand-picked events from the envelope functions, and verify that the triggering is statistically significant. Based on this simple procedure, we have identified many distant events that have triggered activity in both regions, including the recent 08/03/2009 and 04/04/2010 Baja California earthquakes at regional distances, and the 02/27/2010 Chile earthquake at teleseismic distances. Our next steps are to examine the dynamic triggering thresholds in each region, and to understand the triggering potential in terms of frequency, amplitude, incident angle, and type of surface waves.

Aiken, C.; Peng, Z.; Wu, C.

2010-12-01

33

Origin of reverse-graded bedding in air-fall pumice, Coso Range, California  

USGS Publications Warehouse

The origin of reverse grading in air-fall pyroclastic deposits has been ascribed to: (1) changing conditions at an erupting vent; (2) deposition in water; or (3) rolling of large clasts over smaller clasts on the surface of a steep slope. Structural features in a deposit of air-fall pumice lapilli in the Coso Range, California, indicate that reverse grading there formed by a fourth mechanism during flow of pumice. Reverse-graded beds in this deposit occur where pumice lapilli fell on slopes at or near the angle of repose and formed as parts of the blanket of accumulating pumice became unstable and flowed downslope. The process of size sorting during such flow is probably analogous to that which sorts sand grains in a reverse fashion during avalanching on the slip faces of sand dunes, attributed by Bagnold (1954a) to a grain-dispersive pressure acting on particles subjected to a shear stress. In view of the several ways in which air-fall pyroclastic debris may become reverse graded, caution is advised in interpretation of the origin of this structure both in modern and in ancient deposits. ?? 1979.

Duffield, W.A.; Bacon, C.R.; Roquemore, G.R.

1979-01-01

34

Rhyolite thermobarometry and the shallowing of the magma reservoir, Coso volcanic field, California  

USGS Publications Warehouse

The compositionally bimodal Pleistocene Coso volcanic field is located at the western margin of the Basin and Range province ~ 60 km north of the Garlock fault. Thirty-nine nearly aphyric high-silica rhyolite domes were emplaced in the past million years: one at 1 Ma from a transient magma reservoir, one at ~ 0.6 Ma, and the rest since ~ 0.3 Ma. Over the past 0.6 My, the depth from which the rhyolites erupted has decreased and their temperatures have become slightly higher. Pre-eruptive conditions of the rhyolite magmas, calculated from phenocryst compositions using the two-oxide thermometer and the Al-in-hornblende barometer, ranged from 740??C and 270 MPa (2.7 kbar; ~ 10 km depth) for the ~ 0.6 Ma magma, to 770??C and 140 MPa (1.4 kbar; ~ 5.5 km) for the youngest (~ 0.04 Ma) magma. Results are consistent with either a single rhyolitic reservoir moving upward through the crust, or a series of successively shallower reservoirs. As the reservoir has become closer to the surface, eruptions have become both more frequent and more voluminous.

Manley, C.R.; Bacon, C.R.

2000-01-01

35

Study of Hot-Jupiter atmospheres using infrared photometry  

NASA Astrophysics Data System (ADS)

The study of upper atmospheres of Hot-Jupiters has burgeoned in the past two years. This thesis aims to detect thermal radiation from 3 unique Hot-Jupiters, discovered by the XO team, using the Infrared Array Camera (IRAC) on the Spitzer Space Telescope in order to obtain broadband spectra in the infrared to constrain the upper atmospheric temperature structure of Hot-Jupiters. The infrared spectral energy distributions of 3 Hot-Jupiters XO-1b, XO-2b and XO-3b have revealed a presence of a thermally inverted stratosphere in all 3 of them. Since the 3 XO Hot-Jupiters occupy a wide range of substellar point fluxes ( F p ~ 0.49-4.2 10^9 erg cm -2 s -1 ) it allows us to set a threshold bolometric substellar point, flux on the planet above which the intense optical/UV light from the star drives a thermal inversion--a hot stratosphere. Both XO-1b and XO-2h have substellar point fluxes below F p ~ 0.49-4.2 10^9 erg cm -2 s -1 and yet their spectral energy distribution points to a thermally inverted hot stratosphere. XO-3b has a high substellar point flux and as predicted, possesses a thermal inversion as well. Puzzlingly the Hot-Jupiter HD-189733b, which is not in our study, has a similar substellar point flux like XO-1b and yet does not have a. hot stratosphere. We thus suggest that other factors can determine the presence of hot stratospheres in Hot-Jupiters: the substellar point UV flux would be a more appropriate measure of planetary insolation than bolometric flux as upper atmospheric absorbers (TiO, VO and sulfur compounds H 2 and HS) absorb in the optical/UV spectrum and furthermore dynamic effects in the atmosphere like equatorial jets and shocks as suggested by 3D global circulation models can induce stratospheres without extra upper atmospheric absorbers. Obtaining day-side spectra of many more Hot-Jupiters with a wide range of substellar point flux either with existing Cold Spitzer observations in all 4 IRAC channels or during the Warm Spitzer mission could shed more light on why some Hot-Jupiters have hot stratospheres and how exactly they arise. The timing centroids of the secondary eclipses of the 3 Hot-Jupiters have been used to refine their orbital eccentricity. The 3-s upper limit for XO-1b is e cos(o) < 0.0036, where e is eccentricity and o is the argument of the periastron. Similarly we refined the 3-s upper limit on e cos(o) < 0.012 for XO-2b. We refined the eccentricity of XO-3b using the weighted average of the timing centroids of our secondary eclipse measurements to e = 0.277+ 0.004. Radius-age trajectories suggest that if the age of XO-3b is t = [Special characters omitted.] GYr and assuming solar metallicity, the increased tidal heating rate would require a lowered tidal dissipation parameter Q p [Special characters omitted.] 10 6 . Even in the absence of an accurate parallax measurement the radius-age trajectory of XO-3b seems to imply that at least some amount tidal heating must be responsible for the inflated radius R p = [Special characters omitted.] R Jup of XO-3b.

Machalek, Pavel

36

Distribution of Quaternary rhyolite domes of the Coso Range, California: implications for extent of the geothermal anomaly.  

USGS Publications Warehouse

38 separate domes and flows of phenocryst-poor, high-silica rhyolite of similar major element chemical composition were erupted over the past 1My from vents arranged in a crudely S-shaped array atop a granitic horst in the Coso Range, California. Most of the extrusions are probably less than about 0.3My old. The central part of the rhyolite field is characterized by high heat flow, low apparent resistivity, and substantial fumarolic activity indicative of an active geothermal system. -from Authors

Bacon, C.R.; Duffield, W.A.

1980-01-01

37

Hot Air  

NSDL National Science Digital Library

In this activity, learners set up an experiment to investigate the effects of hot air on the path of a laser beam. They observe the wandering position of the laser beam spot on the wall after the light travels through hot air rising from the candle flame. Learners produce a table of observations from both the Cool Air and Hot Air experiments, and answer questions using evidence from their experiment. Apply what learners discover in this experiment to real-life by discussing why stars "twinkle."

Observatory, The U.

2011-01-01

38

Accessory mineral U-Th-Pb ages and 40Ar/39Ar eruption chronology, and their bearing on rhyolitic magma evolution in the Pleistocene Coso volcanic field, California  

USGS Publications Warehouse

We determined Ar/Ar eruption ages of eight extrusions from the Pleistocene Coso volcanic field, a long-lived series of small volume rhyolitic domes in eastern California. Combined with ion-microprobe dating of crystal ages of zircon and allanite from these lavas and from granophyre geothermal well cuttings, we were able to track the range of magma-production rates over the past 650 ka at Coso. In ??? 230 ka rhyolites we find no evidence of protracted magma residence or recycled zircon (or allanite) from Pleistocene predecessors. A significant subset of zircon in the ???85 ka rhyolites yielded ages between ???100 and 200 Ma, requiring that generation of at least some rhyolites involves material from Mesozoic basement. Similar zircon xenocrysts are found in an ???200 ka granophyre. The new age constraints imply that magma evolution at Coso can occur rapidly as demonstrated by significant changes in rhyolite composition over short time intervals (???10's to 100's ka). In conjunction with radioisotopic age constraints from other young silicic volcanic fields, dating of Coso rhyolites highlights the fact that at least some (and often the more voluminous) rhyolites are produced relatively rapidly, but that many small-volume rhyolites likely represent separation from long-lived mushy magma bodies. ?? The Author(s) 2009.

Simon, J.I.; Vazquez, J.A.; Renne, P.R.; Schmitt, A.K.; Bacon, C.R.; Reid, M.R.

2009-01-01

39

Distribution of quaternary rhyolite dome of the Coso Range, California: Implications for extent of the geothermal anomaly  

SciTech Connect

Thirty-eight separate domes and flows of phenocryst-poor, high-silica rhyolite of similar major element chemical composition were erupted over the past 1 m.y. from vents arranged in a crudely S-shaped array atop a granitic horst in the Coso Range, California. Most of the extrusions are probably less than about 0.3 m.y. old. The area is one of Quaternary basaltic volcanism and crustal extension. The central part of the rhyolite field is characterized by high heat flow, low apparent resistivity, and substantial fumarolic activity indicative of an active geothermal system. The immediate source of heat for the surficial geothermal phenomena is probably a silicic magma reservoir that may still contain molten or partially molten material at a depth of at least 8 km beneath the central part of the rhyolite field. Outlying rhyolite extrusions probably reflect the presence of feeder dikes emanating from the reservoir beneath the central region. Azimuths of dikes appear to be parallel to the regional tectonic axis of maximum horizontal compression, analogous to some dike-fed flank eruptions on basaltic shields and andesitic strato-volcanoes. The areal extent of a magma reservoir and the present total heat content of the silicic magma system at Coso may be less than was previously estimated. However, the area is still considered to be one of significant geothermal potential.

Bacon, C.R.; Duffield, W.A.; Nakamura, K.

1980-05-10

40

Julian, B.R., G.R. Foulger, F.C. Monastero and K. Richards-Dinger, Four-dimensional tomography reveals changes in structure 1996 2002 at the Coso geothermal area, California, EOS Trans. AGU, Fall Meet. Suppl., Abstract  

E-print Network

reveals changes in structure 1996 ­ 2002 at the Coso geothermal area, California, EOS Trans. AGU, Fall Meet. Suppl., Abstract S52I-01, 2003. Four-dimensional tomography reveals changes in structure 1996

Foulger, G. R.

41

Evolution of vertical permeability in Coso Geothermal Well 58A-10  

NASA Astrophysics Data System (ADS)

Static temperature (T) profiles in geothermal systems record the relative role of conductive and advective heat transport. Under near steady-state conditions these profiles can reveal the long-term average permeability (k) along the T profile to an order of magnitude by solving for the advective component. Well 58A-10 in the undisturbed margin of the Coso Geothermal Field, CA, offers the opportunity to quantify vertical variations in k that provide a critical insight into the life cycle of geothermal systems. This well has three distinct zones of T gradient: a shallow zone from 400-1100 m depth of 100 C/km, a near-isothermal intermediate zone from 1100-2900 m, and a basal zone >2900 m of 100 C/km. Simple analytical solutions for 1-D heat transport and convective instability can be fit to the observed temperature profiles in the upper two zones. From these solutions the shallow zone requires k<10-17 m2 whereas the intermediate zone requires k>10-13.5 m2, indicating a >103 k difference between these intervals despite similar host rocks and fracture populations. The difference in 1-D, vertical k between the upper two zones appears to arise from the minerals that "heal" fractures as revealed by surface mapping, cuttings and core analysis, and geophysical logs. Initial brittle fracture and frictional slip in low porosity crystalline rocks causes dilation owing to surface roughness along fracture walls, brecciation, and micro-cracking. Yet active precipitation and alteration in geothermal areas implies rapid healing that requires fracture generation or reactivation to maintain k. Fault rocks enriched in neoformed clays minimize dilation during slip and can reduce k to lower than 10-19 m2. Reduced frictional strength in clay-rich faults also promotes their reactivation over the generation of new faults. Since the stability of clays is restricted to relatively low temperature, clay-rich faults are confined to shallow depths. Thus, a fault core enriched in clays at shallow depths becomes a persistent barrier to cross-fault flow that effectively reduces vertical k. Conversely precipitation of calcite or silica dominates healing at greater depth. These minerals retain dilatant behavior during slip that regenerates k as revealed by crack-seal textures. Thus k remains high enough to support convection and isothermal T profiles.

Davatzes, N. C.; Hickman, S. H.

2007-12-01

42

Hot Canyon  

ScienceCinema

This historical film footage, originally produced in the early 1950s as part of a series by WOI-TV, shows atomic research at Ames Laboratory. The work was conducted in a special area of the Laboratory known as the "Hot Canyon."

None

2013-03-01

43

HOT AIR  

NSDL National Science Digital Library

HOT AIR -- The graphical home page of THE ANNALS OF IMPROBABLE RESEARCH FROM MIT provides a different look at scientific research. Check out a schedule of AIR events, an art gallery, and SharewAIR--an interactive and up-to-the-minute moderated forum.

44

Hot Tickets  

ERIC Educational Resources Information Center

This article describes the highlights of this year's BookExpo America (BEA) held at the Los Angeles Convention Center. The attendees at BEA had not minded that the air was recycled, the lighting was fluorescent, and the food was bad. The first hot book sighting came courtesy of Anne Rice. Michelle Moran, author of newly published novel, "The

Fox, Bette-Lee; Hoffert, Barbara; Kuzyk, Raya; McCormack, Heather; Williams, Wilda

2008-01-01

45

Hot tub folliculitis  

MedlinePLUS

Hot tub folliculitis is an infection of the skin around the lower part of the hair shaft ( ... Hot tub folliculitis is caused by the bacteria Pseudomonas aeruginosa . This form of bacteria survives in hot ...

46

Feasibility of CO?/SO? uptake enhancement of calcined limestone modified with rice husk ash during pressurized carbonation.  

PubMed

The calcination/carbonation cycle using calcium-based sorbents appears to be a viable method for carbon dioxide (CO?) capture from combustion gases. Recent attempts to improve the CO?/SO? uptake of a calcium-based sorbent modified by using rice husk ash (RHA) in the hydration process have succeeded in enhancing its effectiveness. The optimal mole ratio of RHA to calcined limestone (M(Si/Ca)) was adjusted to 0.2. The cyclic CO? capture characteristics and the SO? uptake activity of the modified sorbent were evaluated in a calcination/pressurized carbonation reactor system. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) spectrum of the sorbent were also taken to supplement the study. The results showed that the carbonation conversion was greatly increased for the sorbent with M(Si/Ca) ratio of 0.2. For this sorbent formulation the optimal operating conditions were 700-750 C and 0.5-0.7 MPa. CO? absorption was not proportional to CO? concentration in the carbonation atmosphere, but was directly related to reaction time. The CO? uptake decreased in the presence of SO?. SO? uptake increased, and the total calcium utilization was maintained over multiple cycles. Analysis has shown that the silicate component is evenly or well distributed, and this serves as a framework to prevent sintering, thus preserving the available microstructure for reaction. The sorbent also displayed high activity to SO? absorption and could be used to capture CO? and SO? simultaneously. PMID:22054590

Chen, Huichao; Zhao, Changsui; Ren, Qiangqiang

2012-01-01

47

Seismic monitoring of EGS tests at the Coso Geothermal area, California, using accurate MEQ locations and full moment tensors  

SciTech Connect

We studied high-resolution relative locations and full moment tensors of microearthquakes (MEQs) occurring before, during and following Enhanced Geothermal Systems (EGS) experiments in two wells at the Coso geothermal area, California. The objective was to map new fractures, determine the mode and sense of failure, and characterize the stress cycle associated with injection. New software developed for this work combines waveform crosscorrelation measurement of arrival times with relative relocation methods, and assesses confidence regions for moment tensors derived using linearprogramming methods. For moment tensor determination we also developed a convenient Graphical User Interface (GUI), to streamline the work. We used data from the U.S. Navys permanent network of three-component digital borehole seismometers and from 14 portable three-component digital instruments. The latter supplemented the permanent network during injection experiments in well 34A-9 in 2004 and well 34-9RD2 in 2005. In the experiment in well 34A-9, the co-injection earthquakes were more numerous, smaller, more explosive and had more horizontal motion, compared with the pre-injection earthquakes. In the experiment in well 34-9RD2 the relocated hypocenters reveal a well-defined planar structure, 700 m long and 600 m high in the depth range 0.8 to 1.4 km below sea level, striking N 20 E and dipping at 75 to the WNW. The moment tensors show that it corresponds to a mode I (opening) crack. For both wells, the perturbed stress state near the bottom of the well persisted for at least two months following the injection.

Foulger, G.R.; B.R. Julian, B.R.; F. Monastero

2008-04-01

48

Foulger, G.R., B.R. Julian and F.C. Monastero, Microearthquake characterisation of an artificially stimulated hydraulic fracture at the Coso geothermal area, California, EOS Trans. AGU, Fall Meet. Suppl., Abstract, 2006.  

E-print Network

stimulated hydraulic fracture at the Coso geothermal area, California, EOS Trans. AGU, Fall Meet. Suppl., Abstract, 2006. Microearthquake characterisation of an artificially stimulated hydraulic fracture geothermal area. This well was re-drilled February ­ March 2005 with the intention of hydrofracturing

Foulger, G. R.

49

Lead and strontium isotopic evidence for crustal interaction and compositional zonation in the source regions of Pleistocene basaltic and rhyolitic magmas of the Coso volcanic field, California  

USGS Publications Warehouse

The isotopic compositions of Pb and Sr in Pleistocene basalt, high-silica rhyolite, and andesitic inclusions in rhyolite of the Coso volcanic field indicate that these rocks were derived from different levels of compositionally zoned magmatic systems. The 2 earliest rhyolites probably were tapped from short-lived silicic reservoirs, in contrast to the other 36 rhyolite domes and lava flows which the isotopic data suggest may have been leaked from the top of a single, long-lived magmatic system. Most Coso basalts show isotopic, geochemical, and mineralogic evidence of interaction with crustal rocks, but one analyzed flow has isotopic ratios that may represent mantle values (87Sr/86Sr=0.7036,206Pb/204Pb=19.05,207Pb/204Pb=15.62,208Pb/204Pb= 38.63). The (initial) isotopic composition of typical rhyolite (87Sr/86Sr=0.7053,206Pb/204Pb=19.29,207Pb/204Pb= 15.68,208Pb/204Pb=39.00) is representative of the middle or upper crust. Andesitic inclusions in the rhyolites are evidently samples of hybrid magmas from the silicic/mafic interface in vertically zoned magma reservoirs. Silicic end-member compositions inferred for these mixed magmas, however, are not those of erupted rhyolite but reflect the zonation within the silicic part of the magma reservoir. The compositional contrast at the interface between mafic and silicic parts of these systems apparently was greater for the earlier, smaller reservoirs. ?? 1984 Springer-Verlag.

Bacon, C.R.; Kurasawa, H.; Delevaux, M.H.; Kistler, R.W.; Doe, B.R.

1984-01-01

50

Modelling Hot Air Balloons.  

ERIC Educational Resources Information Center

A macroscopic way of modeling hot air balloons using a Newtonian approach is presented. Misleading examples using a car tire and the concept of hot air rising are discussed. Pressure gradient changes in the atmosphere are used to explain how hot air balloons work. (KR)

Brimicombe, M. W.

1991-01-01

51

Hot Weather Tips  

MedlinePLUS

... Form - A A + A You are here Home HOT Weather Tips Printer-friendly version We all suffer in hot weather. However, for elderly and disabled people and ... stress and following these tips for dealing with hot weather. Wear cool clothing: See that the person ...

52

Hot corrosion of Co-Cr, Co-Cr-Al, and Ni-Cr alloys in the temperature range of 700-750 deg C  

NASA Technical Reports Server (NTRS)

The effect of SO3 pressure in the gas phase on the Na2SO4 induced hot corrosion of Co-Cr, Ni-Cr, and Co-Cr-Al alloys was studied in the temperature range 700 to 750 C. The degradation of the Co-Cr and Ni-Cr alloys was found to be associated with the formation of liquid mixed sulfates (CoSO4-Na2SO4 or NiSO4-Na2SO4) which provided a selective dissolution of the Co or Ni and a subsequent sulfidation oxidation mode of attack which prevented the maintenance of a protective Cr2O3 film. A clear mechanism was not developed for the degradation of Co-Cr-Al alloys. A pitting corrosion morphology was induced by a number of different mechanisms.

Chiang, K. T.; Meier, G. H.

1980-01-01

53

HotBot  

NSDL National Science Digital Library

HotBot, a service of HotWired Ventures, uses the Inktomi search engine as the heart of its new Internet search service. It claims to index the full text contents of 50 million Web pages, as well as Usenet news and mailing lists. This would make it the largest search engine on the Internet. HotBot supports Boolean AND/OR/NOT, and phrase searching. It provides relevance feedback with retrieval. It also supports chronological, domain, and geographic searches, as well as media type searches such as Java, VRML, and Acrobat. HotBot is a public "beta" site and encourages feedback and bug reports.

54

6. HOT AIR PORTION OF DAMPERS. Hot Springs National ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. HOT AIR PORTION OF DAMPERS. - Hot Springs National Park, Bathhouse Row, Lamar Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

55

Hot Air Balloon  

NSDL National Science Digital Library

In this activity, learners build a hot air balloon using just a few sheets of tissue paper and a hair dryer. Use this activity to demonstrate how hot air rises due to density and how the volume of gas increases with temperature (Charles's Law).

Centers, Oakland D.

2012-01-01

56

Hot Spot at Yellowstone  

ERIC Educational Resources Information Center

Within this huge national park (over two million acres spread across Wyoming, Montana, and Idaho) are steaming geysers, hot springs, bubbling mudpots, and fumaroles, or steam vents. Drives on the main roads of Yellowstone take tourists through the major hot attractions, which also include Norris Geyser Basin, Upper and Lower Geyser Basin, West

Dress, Abby

2005-01-01

57

Hot subdwarfs revisited  

SciTech Connect

The properties and evolutionary status of the hot B and O subdwarfs are reinvestigated using recent homogeneous grids of hot, high-gravity model atmospheres and detailed convective envelope calculations appropriate to the hot subdwarf region of the H-R diagram discussed by Greenstein and Sargent. An alternative method of analysis of the hot subdwarfs is outlined, where comparisons between observations and theoretical evolutionary tracks are made as close to the fundamental observational results as possible, and are performed directly in the observer's (i.e., (U-B) versus (B-V), or (B-V) versus D(0.1) of H..gamma..) diagram. As an illustrative example of this procedure, we use a set of gravitationally contracting pre--white dwarf evolutionary sequences at M/sub asterisk//M/sub sun/ = 0.4, 0.6, and 0.8 which are found to evolve through the hot subdwarf domain along the extended horizontal branch.

Wesemael, F.; Wingent, D.E.; Cabot, W.; Van Horn, H.M.; Fontaine, G.

1982-03-01

58

Optimization of Hot Standby  

E-print Network

% of the total hot standby capacity can be provided at less than one third of the cost of maximizing hot standby capacity. The appropriate use of this plot can provide useful insights to aid in the decision making process. Minimum Hot Standby, Mlb/hr Cos... provides some flexibility to reduce costs by selecting the most cost effective drive. Which drive to use depends on several factors including he cost of electricity, overall site steam balance and the perceived reliability of turbines versus motors...

de Souza, J.; Holden, D.

2004-01-01

59

CSA Hot Topics Series  

NSDL National Science Digital Library

The Hot Topics series provides a free sampling of the resources in Cambridge Scientific Abstracts (CSA) and the Internet Database Service (IDS). The 30 topics span subjects in the humanities, engineering, environmental policy, and medicine. Each Hot Topic gives an overview of the subject, key citations with abstracts, a list of Websites, a glossary, a comment form so that users can correspond with the editors, and a "source" section, which explains from which of CSA's paid services the resources were culled. The latest hot topic is MicroElectroMechanical systems (MEMS), "small integrated devices or systems that combine electrical and mechanical components."

60

Hot Springs Creek  

USGS Multimedia Gallery

USGS scientist Jennifer Lewicki measures the discharge along a tributary to Hot Springs Creek, Akutan Island, Alaska. Steam (upper left) rises from 3 high-temperature springs that discharge into the tributary....

61

Hot and dark matter  

E-print Network

In this thesis, we build new Effective Field Theory tools to describe the propagation of energetic partons in hot and dense media, and we propose two new reactions for dark matter in the early universe. In the first part, ...

D'Eramo, Francesco

2012-01-01

62

Reactor hot spot analysis  

SciTech Connect

The principle methods for performing reactor hot spot analysis are reviewed and examined for potential use in the Applied Physics Division. The semistatistical horizontal method is recommended for future work and is now available as an option in the SE2-ANL core thermal hydraulic code. The semistatistical horizontal method is applied to a small LMR to illustrate the calculation of cladding midwall and fuel centerline hot spot temperatures. The example includes a listing of uncertainties, estimates for their magnitudes, computation of hot spot subfactor values and calculation of two sigma temperatures. A review of the uncertainties that affect liquid metal fast reactors is also presented. It was found that hot spot subfactor magnitudes are strongly dependent on the reactor design and therefore reactor specific details must be carefully studied. 13 refs., 1 fig., 5 tabs.

Vilim, R.B.

1985-08-01

63

The Hot Tub Mystery  

NSDL National Science Digital Library

This case study sets up a mystery and asks students to solve it using science: why was the couple found dead in their hot tub? The material asks students to connect seemingly unrelated factors, such as blood pressure, hot water and alcohol. The material would be most appropriate for lower level undergraduate students. The case study and teaching notes may be downloaded in PDF format. The site also includes a section for instructor feedback where general comments may be read and contributed.

House, Herbert

2011-01-06

64

Archaeological applications of laser-induced breakdown spectroscopy: an example from the Coso Volcanic Field, California, using advanced statistical signal processing analysis  

SciTech Connect

Over the past quarter century, multielement chemical analysis has become a common means for attributing the provenance of archaeological materials. The Coso Volcanic Field (CVF) in California, USA, contains at least 38 high-silica rhyolite domes, many of which contain obsidian glass that has been quarried for tools by the indigenous population for more than 12,000 years. Artifacts made from CVF obsidian are found throughout the southwestern United States and geochemical sourcing of CVF obsidian has been an important tool in understanding prehistoric Native American trading patterns. Laser-induced breakdown spectroscopy (LIBS) is a simple atomic emission spectroscopic technique that has the potential for real-time man-portable chemical analysis in the field. Because LIBS is simultaneously sensitive to all elements, a single laser shot can be used to record the broadband emission spectra, which provides a ''chemical fingerprint'' of a material. Single-shot broadband LIBS spectra were collected using a commercial benchtop LIBS system for 27 obsidian samples from major sites across the CVF and four additional sites in California and western Nevada outside of CVF. Classification of the samples was performed using partial least-squares discriminant analysis (PLSDA), a common chemometric technique suitable for performing regression on high-dimensional data. Provenance identification for the obsidian samples was evaluated for three separate labeling frameworks. The first framework consisted of a binary classification problem to distinguish CVF samples from non-CVF samples. The second approach focused on the CVF samples with labels that corresponded to the eight separate Coso sites encompassed by the 27 samples. In the third analysis, non-CVF samples were excluded, and the remaining 27 CVF samples were labeled based on groupings defined from previous major and trace element chemical studies, which reduces the number of possible classes from eight to four. Different aspects of the classifier setup considered in this study include the training/testing routine (a 27-fold leave-one-sample-out setup versus a simple split of the data into separate sets for training and evaluation), the number of latent variables used in the regression model, and whether PLSDA operating on the entire broadband LIBS spectrum is superior to that using only a selected subset of LIBS emission lines. The results point to the robustness of the PLSDA technique and suggest that LIBS analysis combined with the appropriate statistical signal processing has the potential to be a useful tool for chemical analysis of archaeological artifacts and geological specimens.

Remus, Jeremiah J.; Gottfried, Jennifer L.; Harmon, Russell S.; Draucker, Anne; Baron, Dirk; Yohe, Robert

2010-05-01

65

IR Hot Wave  

SciTech Connect

The IR Hot Wave{trademark} furnace is a breakthrough heat treatment system for manufacturing metal components. Near-infrared (IR) radiant energy combines with IR convective heating for heat treating. Heat treatment is an essential process in the manufacture of most components. The controlled heating and cooling of a metal or metal alloy alters its physical, mechanical, and sometimes chemical properties without changing the object's shape. The IR Hot Wave{trademark} furnace offers the simplest, quickest, most efficient, and cost-effective heat treatment option for metals and metal alloys. Compared with other heat treatment alternatives, the IR Hot Wave{trademark} system: (1) is 3 to 15 times faster; (2) is 2 to 3 times more energy efficient; (3) is 20% to 50% more cost-effective; (4) has a {+-}1 C thermal profile compared to a {+-}10 C thermal profile for conventional gas furnaces; and (5) has a 25% to 50% smaller footprint.

Graham, T. B.

2010-04-01

66

Hot Oil Removes Wax  

NASA Technical Reports Server (NTRS)

Mineral oil heated to temperature of 250 degrees F (121 degrees C) found effective in removing wax from workpieces after fabrication. Depending upon size and shape of part to be cleaned of wax, part immersed in tank of hot oil, and/or interior of part flushed with hot oil. Pump, fittings, and ancillary tooling built easily for this purpose. After cleaning, innocuous oil residue washed off part by alkaline aqueous degreasing process. Serves as relatively safe alternative to carcinogenic and environmentally hazardous solvent perchloroethylene.

Herzstock, James J.

1991-01-01

67

What's Hot? What's Not?  

ERIC Educational Resources Information Center

When Goldilocks finds three bowls of porridge at different temperatures in the three bears' house, she accurately assesses the situation and comes up with one of the most recognizable lines in children's literature," This porridge is too hot; this porridge is too cold; aahh, this porridge is just right!" Goldilocks' famous line is a perfect

Buczynski, Sandy

2006-01-01

68

Keep It Hot!  

NSDL National Science Digital Library

Student teams design insulated beverage bottles with the challenge to test them to determine which materials (and material thicknesses) work best at insulating hot water to keep it warm for as long as possible. Students test and compare their designs in still air and under a stream of moving air from a house fan.

RESOURCE GK-12 Program,

69

Editor's Note: Hot Properties  

NSDL National Science Digital Library

Properties are "hot," not in terms of real estate but in science class. Here, the editor highlights the feature articles related to this month's theme, Properties of Objects and Materials. With these articles as a guide, you can move students toward a deeper understanding of property. As you do so, they will build a strong foundation for future science learning.

Chris Ohana

2008-01-01

70

Hot off the Press  

ERIC Educational Resources Information Center

In the past, the newspaper was one of the world's most used sources of information. Recently, however, its use has declined due to the popularity of cable television and the Internet. Yet the idea of reading the morning paper with a hot cup of coffee holds many warm memories for children who watched their parents in this daily ritual. In this

Brisco, Nicole D.

2007-01-01

71

Zen Hot Dog Molecules  

ERIC Educational Resources Information Center

Substituted cycloalkanes with one branch illustrating each topic in an instructional unit can serve as summaries or reviews in courses of organic chemistry. The hungry Zen master told the hot dog vendor to make him one with everything. You can do the same for your students.

Ryan, Dennis

2009-01-01

72

Extrapolating to "Hot Jupiters"  

E-print Network

Extrapolating to "Hot Jupiters" P. Zarka LESIA, Observatoire de Paris, Meudon Collaborators : R-15) HOM (L=7-11) Io-DAM (L=6) = 90° non-Io-DAM ? B [Zarka, 2000] · 5 radio planets · 6 LF (KOM, Lyman-) [Prangé et al., 1996] #12;[Zarka et al., 2001] Planetary Radio Emissions · nonthermal cyclotron

Demoulin, Pascal

73

Hot piston ring tests  

NASA Technical Reports Server (NTRS)

As part of the DOE/NASA Automotive Stirling Engine Project, tests were made at NASA Lewis Research Center to determine whether appendix gap losses could be reduced and Stirling engine performance increased by installing an additional piston ring near the top of each piston dome. An MTI-designed upgraded Mod I Automotive Stirling Engine was used. Unlike the conventional rings at the bottom of the piston, these hot rings operated in a high temperature environment (700 C). They were made of a high temperature alloy (Stellite 6B) and a high temperature solid lubricant coating (NASA Lewis-developed PS-200) was applied to the cylinder walls. Engine tests were run at 5, 10, and 15 MPa operating pressure over a range of operating speeds. Tests were run both with hot rings and without to provide a baseline for comparison. Minimum data to assess the potential of both the hot rings and high temperature low friction coating was obtained. Results indicated a slight increase in power and efficiency, an increase over and above the friction loss introduced by the hot rings. Seal leakage measurements showed a significant reduction. Wear on both rings and coating was low.

Allen, David J.; Tomazic, William A.

1987-01-01

74

Hot Dog Champ Defeated  

E-print Network

Broadcast Transcript: Arthritic jaw? Recent wisdom tooth extraction? The universe saying "It is time"? Whatever. All we know is that Japan's six year domination of Nathan's Famous July 4th Hot Dog Eating contest at Coney Island came to an end...

Hacker, Randi; Tsutsui, William; Bleier, R.H.

2007-07-25

75

Kamchatka's thermal hot springs  

NSDL National Science Digital Library

The Kamchatka Peninsula is featured in this website including information on geography, climate, fauna, flora, volcanoes, thermal springs, Valley of Geysers, native people, and options for travel in Kamchatka. This specific page highlights a selection of Kamchatka's hot springs, presenting basic information on temperature ranges, chemical and physical characteristics, surrounding vegetation, and general location.

Kamchatka, Vision O.

76

Some Like it Hot  

NSDL National Science Digital Library

NASA Astrobiologist Jack Farmer is featured in this web article that focuses on microrganisms found in Yellowstone hot springs and ocean floor hydrothermal vents. Included within the article are numerous links to concepts, resources, and further readings involving exobiology. and microbiology. Downloadable Quick time videos of a discussion with Farmer and hydrothermal vent activity at the ocean floor are also available.

Bortman, Henry; Magazine, Astrobiology

77

OECD Focus Hot File  

NSDL National Science Digital Library

In each issue of the Organization for Economic Co-operation and Development (OECD)'s Focus Hot File, recent books and government reports of interest are listed with summaries and contact information. Past listings may be browsed by country in the Focus Compendium, and related publications are hyperlinked throughout.

78

HOT GAS CLEANUP PROCESS  

EPA Science Inventory

The report gives results of a study to identify and classify 22 hot gas cleanup (HGC) processes for desulfurizing reducing gases at above 430 C according to absorbent type into groups employing solid, molten salt, and molten metal absorbents. It describes each process in terms of...

79

Hot-hole photodetectors  

NASA Astrophysics Data System (ADS)

By injecting high-energy charge carriers (dubbed 'hot holes') into a semiconductor, scientists have succeeded in realizing photodetectors capable of detecting ultralong wavelengths. Unil Perera from Georgia State University in the USA explains how the devices work and how they can be improved.

2014-05-01

80

Exercising Safely in Hot Weather  

MedlinePLUS

... older adults and people with health problems. Being hot for too long can cause hyperthermiaa heat- ... those who want to be active when its hot outside: l Check the weather forecast. If its ...

81

Hot Tub Rash (Pseudomonas Folliculitis)  

MedlinePLUS

newsletter | contact Share | Hot Tub Rash ( Pseudomonas Folliculitis) Information for adults A A A This image displays follicular elevations of the skin and small pus-filled lesions. Overview Hot tub rash ( Pseudomonas folliculitis) is an infection of ...

82

Hot Tub Rash (Pseudomonas Dermatitis/Folliculitis)  

MedlinePLUS

... How Do I Protect Myself and My Family? "Hot Tub Rash" ( Pseudomonas Dermatitis / Folliculitis) Below are answers ... hot tub rash and healthy swimming. What is Hot Tub Rash? Hot tub rash, or dermatitis, is ...

83

Hot spring metagenomics.  

PubMed

Hot springs have been investigated since the XIX century, but isolation and examination of their thermophilic microbial inhabitants did not start until the 1950s. Many thermophilic microorganisms and their viruses have since been discovered, although the real complexity of thermal communities was envisaged when research based on PCR amplification of the 16S rRNA genes arose. Thereafter, the possibility of cloning and sequencing the total environmental DNA, defined as metagenome, and the study of the genes rescued in the metagenomic libraries and assemblies made it possible to gain a more comprehensive understanding of microbial communities-their diversity, structure, the interactions existing between their components, and the factors shaping the nature of these communities. In the last decade, hot springs have been a source of thermophilic enzymes of industrial interest, encouraging further study of the poorly understood diversity of microbial life in these habitats. PMID:25369743

Lpez-Lpez, Olalla; Cerdn, Mara Esperanza; Gonzlez-Siso, Mara Isabel

2013-01-01

84

The hot chocolate effect  

NASA Astrophysics Data System (ADS)

The ''hot chocolate effect'' was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one-quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the 10% accuracy of the experiments.

Crawford, Frank S.

1982-05-01

85

THE HOT CHOCOLATE EFFECT  

SciTech Connect

The "hot chocolate effect" was investigated quantitatively, using water. If a tall glass cylinder is filled nearly completely with water and tapped on the bottom with a softened mallet one can detect the lowest longitudinal mode of the water column, for which the height of the water column is one quarter wavelength. If the cylinder is rapidly filled with hot tap water containing dissolved air the pitch of that mode may descend by nearly three octaves during the first few seconds as the air comes out of solution and forms bubbles. Then the pitch gradually rises as the bubbles float to the top. A simple theoretical expression for the pitch ratio is derived and compared with experiment. The agreement is good to within the ten percent accuracy of the experiments.

Crawford, Frank S.

1980-12-01

86

Hot refueling hazards.  

PubMed

Hot refueling in the special operations community has several potential hazards which can accompany the operation. The MC-130 Panel Operator's (PO) position is located in the exhaust of the number 3 engine, subjecting him to fumes, heat, and exhaust blast. The hypothesis was that time constraints should be implemented to the work load due to heat and carbon monoxide exposure. The hypothesis was confirmed for heat exposure but not for significant carbon monoxide exposure. PMID:2496343

Hammer, D L

1989-03-01

87

Quarkonium in Hot Medium  

SciTech Connect

I review recent progress in studying quarkonium properties in hot medium as well as possible consequences for quarkonium production in heavy ion collisions. There has been considerable interest in studying quarkonia in hot medium since the publication of the famous Matsui and Satz paper. It has been argued that color screening in a deconfined QCD medium will suppress the existence of quarkonium states, signaling the formation of a quark-gluon plasma (QGP) in heavy-ion collisions. Although this idea was proposed a long time ago, first principle QCD calculations, which go beyond qualitative arguments, have been performed only recently. Such calculations include lattice QCD determinations of quarkonium correlators; potential model calculations of the quarkonium spectral functions with potentials based on lattice QCD, as well as effective field theory approaches that justify potential models and reveal new medium effects. Spectral properties of heavy quark bound states are important ingredients in modeling of heavy quarkonium production in hot medium as will be discussed later.

Petreczky, P.

2010-08-02

88

PREFACE: Hot Quarks 2004  

NASA Astrophysics Data System (ADS)

Why another conference devoted to ultra-relativistic heavy-ion physics? As we looked around the landscape of the existing international conferences and workshops, we realized that there was not a single one tailored to the people who are most directly involved with the actual research work: students, post-docs, and junior faculty/research scientists. Of course there are schools, but that was not what we had in mind. We wanted a meeting where young researchers could come together to discuss in depth the physics that they are working on without any hindrance. The major conferences have very limited time for discussions which is often shared amongst the most established. This leaves little room for young people to ask their questions and to get the detailed feedback which they deserve and which satisfies their curiosity. A discussion-driven workshop, centering on those without whom there will be no futurethat seemed like what was needed. And thus the Hot Quarks workshop was born. The aim of Hot Quarks was to enhance the direct exchange of scientific information among the younger members of the community, from both experiment and theory. Participation was by invitation only in order to emphasize the contributions from junior researchers. This approach makes the workshop unique among the many forums in the field. For young scientists it represented an opportunity for exposure that they would not have had in one of the major conferences. The hope is that this meeting has helped to stimulate the next generation of scientists in our field and, at the same time, strengthened their sense of community. It all came together from 18 24 July 2004, when the 77 participants met at The Inn at Snakedance in the Taos Ski Valley, New Mexico, USA, for the first Hot Quarks workshop. Photograph Participants gather in the sunshine at the foot of the Taos Ski Valley chairlift. By all accounts, Hot Quarks 2004 was a great success. Every participant had the opportunity to present her or his research and we spent an entire week talking physics and having fun from breakfast in the morning until late at night. A symbolic award was instituted for the best presentation at the workshop, dedicated to the memory of Klaus Kinder-Geiger, a sharp and brilliant young theorist who perished in the crash of Swissair Flight 111 on 2 September 1998 off the coast of Nova Scotia. It went to Denesh Molnar from Ohio State University for his outstanding talk on parton coalescence. The organizers wish to extend their gratitude to all participants for the high quality presentations making Hot Quarks 2004 a notable event. We are also very grateful for the superb hospitality of the staff of the Snakedance Inn, in particular Mitch Daniels who worked sheer miracles. Given the success of the first Hot Quarks workshop we decided to organize a second one, possibly even turning Hot Quarks into a series. The next meeting will be held in the late spring of 2006, probably in Italy. We hope it will be as memorable as the first one! Last but not least, we wish to thank all the generous sponsors of the conference: Brookhaven National Laboratory, European Organization for Nuclear Research (CERN), Gesellschaft fA~ 1/4 r Schwerionenforschung (GSI), Institute of Physics Publishing, Los Alamos National Laboratory, National Science Foundation, and Vanderbilt University. We are grateful for their support and are particularly happy that this support came from institutions both in the US and in Europe and from all the main experimental facilities that pursue a prominent heavy-ion program. Their support was essential for the success of a workshop targeting young scientists.

Antinori, Federico; Bass, Steffen A.; Bellwied, Rene; Ullrich, Thomas; Velkovska, Julia; Wiedemann, Urs

2005-04-01

89

Hot cell examination table  

DOEpatents

A table for use in a hot cell or similar controlled environment for use in examining specimens. The table has a movable table top that can be moved relative to a table frame. A shaft is fixedly mounted to the frame for axial rotation. A shaft traveler having a plurality of tilted rollers biased against the shaft is connected to the table top such that rotation of the shaft causes the shaft traveler to roll along the shaft. An electromagnetic drive is connected to the shaft and the frame for controllably rotating the shaft.

Gaal, Peter S. (Monroeville, PA); Ebejer, Lino P. (Weston, MA); Kareis, James H. (Slickville, PA); Schlegel, Gary L. (McKeesport, PA)

1991-01-01

90

The Hot Tub Mystery  

NSDL National Science Digital Library

Roma and Clint Underhill are relaxing after a stressful day in their hot tub with some wine. But tragedy strikes, and the next morning their lifeless bodies are found in the water by their housekeeper. The paramedics who respond to her frantic 911 call pronounce the couple dead at the scene and call in the police to investigate. Developed for use in a lower-level undergraduate course on human physiology, students work through the various parts of this interrupted case to discover the cause of death, and in the process learn about blood pressure regulation.

House, Herbert

2005-01-01

91

Hot air drum evaporator  

DOEpatents

An evaporation system for aqueous radioactive waste uses standard 30 and 55 gallon drums. Waste solutions form cascading water sprays as they pass over a number of trays arranged in a vertical stack within a drum. Hot dry air is circulated radially of the drum through the water sprays thereby removing water vapor. The system is encased in concrete to prevent exposure to radioactivity. The use of standard 30 and 55 gallon drums permits an inexpensive compact modular design that is readily disposable, thus eliminating maintenance and radiation build-up problems encountered with conventional evaporation systems.

Black, Roger L. (Idaho Falls, ID)

1981-01-01

92

Hot and Cold  

NSDL National Science Digital Library

In this activity, learners explore temperature changes from chemical reactions by mixing urea with water in one flask and mixing calcium chloride with water in another flask. They observe that the urea flask gets cold and the calcium chloride flask gets hot. The main idea is that some chemical processes release heat energy and are exothermic, while some chemical processes absorb heat energy and are endothermic. This activity is currently used in the Nature of Matter Unit in OMSI's Chemistry Lab. Cost estimates are per 100 learners.

Industry, Oregon M.

1997-01-01

93

Radiations from hot nuclei  

NASA Technical Reports Server (NTRS)

The investigation indicates that nuclei with excitation energy of a few hundred MeV to BeV are more likely to radiate hot nuclear clusters than neutrons. These daughter clusters could, furthermore, de-excite emitting other hot nuclei, and the chain continues until these nuclei cool off sufficiently to evaporate primarily neutrons. A few GeV excited nuclei could radiate elementary particles preferentially over neutrons. Impact of space radiation with materials (for example, spacecraft) produces highly excited nuclei which cool down emitting electromagnetic and particle radiations. At a few MeV excitation energy, neutron emission becomes more dominant than gamma-ray emission and one often attributes the cooling to take place by successive neutron decay. However, a recent experiment studying the cooling process of 396 MeV excited Hg-190 casts some doubt on this thinking, and the purpose of this investigation is to explore the possibility of other types of nuclear emission which might out-compete with neutron evaporation.

Malik, F. Bary

1993-01-01

94

Hot Subdwarf Stars  

NASA Astrophysics Data System (ADS)

Hot subdwarf stars (sdBs, sdOs) are core helium-burning stars at the blue end of the horizontal branch or have evolved even beyond that stage. They are found in all Galactic stellar populations and are sufficiently common to account for the UV-upturn of early-type galaxies. About half of the sdBs reside in close binaries; companions are white dwarfs or low-mass main-sequence stars. Binary population-synthesis models explain naturally the actual sdB binary fractions of field and globular cluster stars as well as of He-sdOs if white-dwarf mergers are considered. Hot helium flashes explain the chemical composition of He-sdOs. Asteroseismology of a dozen pulsating sdB stars allowed determination of their masses and detection of a planet to V391 Peg. The discoveries of an sdO star unbound to the Galaxy, potential SN Ia progenitors and probably a hidden population of neutron stars or black hole companions have great impact on astrophysics at large.

Heber, Ulrich

2009-09-01

95

Hot, Dry and Cloudy  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Click on the image for movie of Hot, Dry and Cloudy

This artist's concept shows a cloudy Jupiter-like planet that orbits very close to its fiery hot star. NASA's Spitzer Space Telescope was recently used to capture spectra, or molecular fingerprints, of two 'hot Jupiter' worlds like the one depicted here. This is the first time a spectrum has ever been obtained for an exoplanet, or a planet beyond our solar system.

The ground-breaking observations were made with Spitzer's spectrograph, which pries apart infrared light into its basic wavelengths, revealing the 'fingerprints' of molecules imprinted inside. Spitzer studied two planets, HD 209458b and HD 189733b, both of which were found, surprisingly, to have no water in the tops of their atmospheres. The results suggest that the hot planets are socked in with dry, high clouds, which are obscuring water that lies underneath. In addition, HD209458b showed hints of silicates, suggesting that the high clouds on that planet contain very fine sand-like particles.

Capturing the spectra from the two hot-Jupiter planets was no easy feat. The planets cannot be distinguished from their stars and instead appear to telescopes as single blurs of light. One way to get around this is through what is known as the secondary eclipse technique. In this method, changes in the total light from a so-called transiting planet system are measured as a planet is eclipsed by its star, vanishing from our Earthly point of view. The dip in observed light can then be attributed to the planet alone.

This technique, first used by Spitzer in 2005 to directly detect the light from an exoplanet, currently only works at infrared wavelengths, where the differences in brightness between the planet and star are less, and the planet's light is easier to pick out. For example, if the experiment had been done in visible light, the total light from the system would appear to be unchanged, even as the planet disappeared from view.

To capture spectra of the planets, Spitzer observed their secondary eclipses with its spectrograph. It took a spectrum of a star together with its planet, then, as the planet disappeared from view, a spectrum of just the star. By subtracting the spectrum of the star from the spectrum of the star and planet together, astronomers were able to determine the spectrum of the planet itself.

Neither of the parent stars for HD 209458b or HD 189733b can be seen with the naked eye. HD 209458b is located about 153 light-years away in the constellation Pegasus, while HD 189733b is about 62 light-years away in the constellation Vulpecula. Both planets zip around their stars in very tight orbits; HD 209458b circles once every 3.5 days, while HD 189733b orbits once every 2.2 days.

Of the approximately 200 known exoplanets, there are 12 besides HD 209458b and HD 189733b whose orbits are inclined in such a way that, from our point of view, they pass in front of their stars. At least three of these transiting exoplanets are bright enough to follow in the footsteps of HD 209458b and HD 189733 and reveal their infrared spectra to Spitzer. Astronomers hope to use Spitzer's spectrograph in the future to study HD 209458b and HD 189733b again in much greater detail, and to examine some of the other candidates for the first time.

2007-01-01

96

Full of Hot Air: Hot Air Balloon Building  

NSDL National Science Digital Library

In this activity, learners create a model of a hot air balloon using tissue paper and a hairdryer. Educators can use this activity to introduce learners to density and its role in why things float. This activity page features a fun how-to video that shows learners and educators how to make the hot air balloons.

Houston, Children'S M.

2010-01-01

97

TRUEX hot demonstration  

SciTech Connect

In FY 1987, a program was initiated to demonstrate technology for recovering transuranic (TRU) elements from defense wastes. This hot demonstration was to be carried out with solution from the dissolution of irradiated fuels. This recovery would be accomplished with both PUREX and TRUEX solvent extraction processes. Work planned for this program included preparation of a shielded-cell facility for the receipt and storage of spent fuel from commercial power reactors, dissolution of this fuel, operation of a PUREX process to produce specific feeds for the TRUEX process, operation of a TRUEX process to remove residual actinide elements from PUREX process raffinates, and processing and disposal of waste and product streams. This report documents the work completed in planning and starting up this program. It is meant to serve as a guide for anyone planning similar demonstrations of TRUEX or other solvent extraction processing in a shielded-cell facility.

Chamberlain, D.B.; Leonard, R.A.; Hoh, J.C.; Gay, E.C.; Kalina, D.G.; Vandegrift, G.F.

1990-04-01

98

Circuit hot electron effect simulation  

Microsoft Academic Search

Hot electron effects resulting from high electric fields in submicron devices can severely degrade device characteristics. As a result, severe performance degradation can occur at the circuit level. No simulator exists to predict this effect. The purpose of this paper is to present circuit hot electron effect simulation using our recently developed simulator. As a result, a circuit performance degradation

S. Aur; D. E. Hocevar; Ping Yang

1987-01-01

99

Spectral Modeling Hot Star Winds  

E-print Network

Spectral Modeling of X-Rays from Hot Star Winds Emma Wollman Advisor: David Cohen #12;Hot Stars ·· Short-livedShort-lived (~ 1-10 million yrs)(~ 1-10 million yrs) #12;Stellar Winds · Net momentum · More luminosity !"stronger wind · Mass-loss rate determines the fate of the star #12;X-ray Production

Cohen, David

100

Hot hollow cathode gun assembly  

DOEpatents

A hot hollow cathode deposition gun assembly includes a hollow body having a cylindrical outer surface and an end plate for holding an adjustable heat sink, the hot hollow cathode gun, two magnets for steering the plasma from the gun into a crucible on the heat sink, and a shutter for selectively covering and uncovering the crucible.

Zeren, J.D.

1983-11-22

101

Mammoth Hot Springs Online Tour  

NSDL National Science Digital Library

This Yellowstone National Park website offers an online tour of the Mammoth Hot Springs. Prominent hot springs and terraces are highlighted with photos and information concerning their cycles of activity. Similar tours of the Old Faithful area, the Norris Geyser Basin, the Fountain Paint Pots, and the Grand Canyon of Yellowstone are also available online.

Park, Yellowstone N.

102

SOURCE ASSESSMENT: ASPHALT HOT MIX  

EPA Science Inventory

This report summarizes data on air emissions from the asphalt hot mix industry. A representative asphalt hot mix plant was defined, based on the results of an industrial survey, to assess the severity of emissions from this industry. Source severity was defined as the ratio of th...

103

Hot oxygen corona at Europa  

NASA Astrophysics Data System (ADS)

A model of the hot oxygen exosphere at Europa was constructed. The source term for the hot atoms was assumed to be dissociative recombination of O2+ and Liouville's theorem was used to calculate their altitude distribution. It was found that near the surface the hot oxygen density is in excess of 200 cm-3, dropping to a value on the order of 50 cm-3 at 1500 km. These calculations indicate that the hot atomic oxygen densities are considerably less than the thermal molecular oxygen ones, but slightly larger than the measured sodium values. The escape flux of the hot oxygen atoms was calculated to be on the order of 1.4108 atoms cm-2 sec-1. This corresponds to a global escape rate of 4.41025 atoms sec-1, which is more than an order of magnitude less than the estimated atmospheric sputtering rate.

Nagy, Andrew F.; Kim, Jhoon; Cravens, Thomas E.; Kliore, Arvydas J.

104

Keep It Cool in Hot Weather  

MedlinePLUS

... in the Summer Sun Keep it Cool in Hot Weather Keep it Cool in Hot Weather Advice for Older People Applies to All ... factors that can increase risk include an extremely hot home, lack of transportation, overdressing and visiting overcrowded ...

105

Hot-Jupiters and hot-Neptunes: a common origin?  

E-print Network

We compare evolutionary models for close-in exoplanets coupling irradiation and evaporation due respectively to the thermal and high energy flux of the parent star with observations of recently discovered new transiting planets. The models provide an overall good agreement with observations, although at the very limit of the quoted error bars of OGLE-TR-10, depending on its age. Using the same general theory, we show that the three recently detected hot-Neptune planets (GJ436, $\\rho$ Cancri, $\\mu$ Ara) may originate from more massive gas giants which have undergone significant evaporation. We thus suggest that hot-Neptunes and hot-Jupiters may share the same origin and evolution history. Our scenario provides testable predictions in terms of the mass-radius relationships of these hot-Neptunes.

I. Baraffe; G. Chabrier; T. S. Barman; F. Selsis; F. Allard; P. H. Hauschildt

2005-05-03

106

Hot and super-hot hydrogen atoms in microwave plasma  

SciTech Connect

'Super-hot' (kinetic energy {approx}4-8 eV) and 'hot' (kinetic energy {approx}0.3 eV) H atoms were detected in a surface wave (500 MHz) generated H{sub 2} plasma column, at pressure p=0.01 mbar, from the analysis of the H{sub {beta}}, H{sub {gamma}}, H{sub {delta}}, and H{sub {epsilon}} emission line profiles. These profiles were found to evolve from single Gaussian to bi-Gaussian toward the plasma column end. Population inversion between the levels 5{yields}4 and 6{yields}4 was detected. At pressure p=0.2 mbar, super-hot atoms were not detected and the temperature of the hot atoms was found to increase with the upper level principal quantum number.

Tatarova, E.; Felizardo, E.; Dias, F. M.; Lino da Silva, M.; Ferreira, C. M. [Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Gordiets, B. [Lebedev Physics Institute, 11991 Moscow (Russian Federation)

2009-11-02

107

Neptune's 'Hot' South Pole  

NASA Technical Reports Server (NTRS)

These thermal images show a 'hot' south pole on the planet Neptune. These warmer temperatures provide an avenue for methane to escape out of the deep atmosphere.

The images were obtained with the Very Large Telescope in Chile, using an imager/spectrometer for mid-infrared wavelengths on Sept. 1 and 2, 2006. The telescope is operated by the European Organization for Astronomical Research in the Southern Hemisphere (known as ESO).

Scientists say Neptune's south pole is 'hotter' than anywhere else on the planet by about 10 degrees Celsius (50 degrees Fahrenheit). The average temperature on Neptune is about minus 200 degrees Celsius (minus 392 degrees Fahrenheit).

The upper left image samples temperatures near the top of Neptune's troposphere (near 100 millibar pressure, which is one-tenth the Earth atmospheric pressure at sea level). The hottest temperatures are indicated at the lower part of the image, at Neptune's south pole (see the graphic at the upper right). The lower two images, taken 6.3 hours apart, sample temperatures at higher altitudes in Neptune's stratosphere. They do show generally warmer temperatures near, but not at, the south pole. They also show a distinct warm area which can be seen in the lower left image and rotated completely around the back of the planet and returned to the earth-facing hemisphere in the lower right image.

2007-01-01

108

Solutions for Hot Situations  

NASA Technical Reports Server (NTRS)

From the company that brought the world an integral heating and cooling food service system after originally developing it for NASA's Apollo Program, comes yet another orbital offshoot: a product that can be as thin as paper and as strong as steel. Nextel Ceramic Textiles and Composites from 3M Company offer space-age protection and innovative solutions for hot situations, ranging from NASA to NASCAR. With superior thermal protection, Nextel fabrics, tape, and sleevings outperform other high temperature textiles such as aramids, carbon, glass, and quartz, permitting engineers and manufacturers to handle applications up to 2,500 F (1,371 C). The stiffness and strength of Nextel Continuous Ceramic Fibers make them a great match for improving the rigidity of aluminum in metal matrix composites. Moreover, the fibers demonstrate low shrinkage at operating temperatures, which allow for the manufacturing of a dimensionally stable product. These novel fibers also offer excellent chemical resistance, low thermal conductivity, thermal shock resistance, low porosity, and unique electrical properties.

2003-01-01

109

Really Hot Stars  

NASA Astrophysics Data System (ADS)

Spectacular VLT Photos Unveil Mysterious Nebulae Summary Quite a few of the most beautiful objects in the Universe are still shrouded in mystery. Even though most of the nebulae of gas and dust in our vicinity are now rather well understood, there are some which continue to puzzle astronomers. This is the case of a small number of unusual nebulae that appear to be the subject of strong heating - in astronomical terminology, they present an amazingly "high degree of excitation". This is because they contain significant amounts of ions, i.e., atoms that have lost one or more of their electrons. Depending on the atoms involved and the number of electrons lost, this process bears witness to the strength of the radiation or to the impact of energetic particles. But what are the sources of that excitation? Could it be energetic stars or perhaps some kind of exotic objects inside these nebulae? How do these peculiar objects fit into the current picture of universal evolution? New observations of a number of such unusual nebulae have recently been obtained with the Very Large Telescope (VLT) at the ESO Paranal Observatory (Chile). In a dedicated search for the origin of their individual characteristics, a team of astronomers - mostly from the Institute of Astrophysics & Geophysics in Lige (Belgium) [1] - have secured the first detailed, highly revealing images of four highly ionized nebulae in the Magellanic Clouds, two small satellite galaxies of our home galaxy, the Milky Way, only a few hundred thousand light-years away. In three nebulae, they succeeded in identifying the sources of energetic radiation and to eludicate their exceptional properties: some of the hottest, most massive stars ever seen, some of which are double. With masses of more than 20 times that of the Sun and surface temperatures above 90 000 degrees, these stars are truly extreme. PR Photo 09a/03: Nebula around the hot star AB7 in the SMC. PR Photo 09b/03: Nebula near the hot Wolf-Rayet star BAT99-2 in the LMC. PR Photo 09c/03: Nebula near the hot binary star BAT99-49 in the LMC. PR Photo 09d/03: The N44C Nebula in the LMC. Four unique images of highly excited nebulae in the Magellanic Clouds ESO PR Photo 09a/03 ESO PR Photo 09a/03 [Preview - JPEG: 400 x 472 pix - 74k [Normal - JPEG: 800 x 943 pix - 720k] [Full-Res - JPEG: 1200 x 1414 pix - 1.2M] ESO PR Photo 09b/03 ESO PR Photo 09b/03 [Preview - JPEG: 400 x 466 pix - 70k [Normal - JPEG: 800 x 931 pix - 928k] [Full-Res - JPEG: 1200 x 1397 pix - 1.8M] ESO PR Photo 09c/03 ESO PR Photo 09c/03 [Preview - JPEG: 400 x 469 pix - 74k [Normal - JPEG: 800 x 937 pix - 1.1M] [Full-Res - JPEG: 1200 x 1405 pix - 2.2M] ESO PR Photo 09d/03 ESO PR Photo 09d/03 [Preview - JPEG: 400 x 473 pix - 28k [Normal - JPEG: 800 x 945 pix - 368k] [Full-Res - JPEG: 1200 x 1418 pix - 600k] Captions: PR Photo 09a/03 is a reproduction of a "near-true" three-colour composite image of the highly excited nebula around the hot double star AB7 in the Small Magellanic Cloud (SMC), obtained in January 2002 with the FORS1 multi-mode instrument at the 8.2-m VLT MELIPAL telescope at the Paranal Observatory (Chile). It is based on three exposures through narrow-band optical (interference) filters that isolate the light from specific atoms and ions. In this rendering, the blue colour represents the light from singly ionized Helium (He II; wavelength 468.6 nm; exposure time 30 min), green corresponds to doubly ionized oxygen ([O III]; 495.7 + 500.7 nm; 5 min) and red to hydrogen atoms (H; H-alpha line at 656.2 nm; 5 min). Of these three ions, He II is the tracer of high excitation, i.e. the bluest areas of the nebula are the hottest. The sky field measures 400 x 400 arcsec2; the original pixel size on the 2k x 2k CCD is 0.23 arcsec. North is up and east to the left. Before combination, the CCD frames were flat-fielded and cleaned of cosmic-rays. Moreover, the stars in the blue (He II) image were removed in order to provide a clearer view of the surrounding nebular emission. The reproduced brightness is proportional to the squar

2003-04-01

110

Hot Spot Cosmic Accelerators  

NASA Astrophysics Data System (ADS)

The Universe is a violent place - as astronomers use increasingly sensitive means and methods to study the diverse processes out there, they become aware of the extraordinary forces acting in the space that surrounds us. With larger telescopes and ever-more sophisticated instruments, new information is gained about remote celestial objects and their behaviour. Among the most intriguing ones are the radio galaxies which emit prodiguous amounts of energy, in the form of fast-moving particles and intense electromagnetic radiation. One of these is known as 3C 445 ; it is located near the celestial equator within the zodiacal constellation Aquarius (The Waterman), at a distance of about 1 billion light-years. It most probably harbours a black hole at its centre, more massive than the one at the centre of our own galaxy, the Milky Way ( ESO PR 19/02 ). This galaxy was first observed from Cambridge (United Kingdom) in the 1950's and was listed as radio source no. 445 in the Third Cambridge Catalogue (1959), hence the name. Later observations revealed a strong outflow from this galaxy's active centre, visible on radio maps as two opposite plasma jets with strong synchrotron radiation ( [2]) originating from rapidly moving electrons in the associated magnetic field (image "a" in PR Photo 26/02 ). Now, a trio of European astronomers [1] have used two advanced instruments, ISAAC and FORS1 on the 8.2-m VLT ANTU telescope at the ESO Paranal Observatory (Chile) to obtain near-infrared images of these jets (images "b" and "c" in PR Photo 26/02 ). As can be clearly seen on the radio picture of 3C 445 obtained with the NRAO Very Large Array (VLA) radio facility ("a"), the plasma jets of fast particles emanating from the galaxy ram into the surrounding intergalactic medium (mostly primordial hydrogen), thereby producing two "shocks" , both at a distance of approximately 1.5 million light-years from the central galaxy and with particularly strong synchrotron emission. With a total length of more than 3 million light-years, or no less than one-and-a-half times the distance from the Milky Way to the Andromeda galaxy, this structure is indeed gigantic. The region where the jets collide with the intergalactic medium are known as " hot spots ". Superposing the intensity contours of the radio emission from the southern "hot spot" on a near-infrared J-band (wavelength 1.25 m) VLT ISAAC image ("b") shows three distinct emitting areas; they are even better visible on the I-band (0.9 m) FORS1 image ("c"). This emission is obviously associated with the shock front visible on the radio image. This is one of the first times it has been possible to obtain an optical/near-IR image of synchrotron emission from such an intergalactic shock and, thanks to the sensitivity and image sharpness of the VLT, the most detailed view of its kind so far . The central area (with the strongest emission) is where the plasma jet from the galaxy centre hits the intergalactic medium. The light from the two other "knots", some 10 - 15,000 light-years away from the central "hot spot", is also interpreted as synchrotron emission. However, in view of the large distance, the astronomers are convinced that it must be caused by electrons accelerated in secondary processes at those sites . The new images thus confirm that electrons are being continuously accelerated in these "knots" - hence called "cosmic accelerators" - far from the galaxy and the main jets, and in nearly empty space. The exact physical circumstances of this effect are not well known and will be the subject of further investigations. The present VLT-images of the "hot spots" near 3C 445 may not have the same public appeal as some of those beautiful images that have been produced by the same instruments during the past years. But they are not less valuable - their unusual importance is of a different kind, as they now herald the advent of fundamentally new insights into the

2002-11-01

111

Hot Hydrogen Test Facility  

SciTech Connect

The core in a nuclear thermal rocket will operate at high temperatures and in hydrogen. One of the important parameters in evaluating the performance of a nuclear thermal rocket is specific impulse, ISP. This quantity is proportional to the square root of the propellant's absolute temperature and inversely proportional to square root of its molecular weight. Therefore, high temperature hydrogen is a favored propellant of nuclear thermal rocket designers. Previous work has shown that one of the life-limiting phenomena for thermal rocket nuclear cores is mass loss of fuel to flowing hydrogen at high temperatures. The hot hydrogen test facility located at the Idaho National Lab (INL) is designed to test suitability of different core materials in 2500 deg. C hydrogen flowing at 1500 liters per minute. The facility is intended to test low activity uranium containing materials but is also suited for testing cladding and coating materials. In this first installment the facility is described. Automated data acquisition, flow and temperature control, vessel compatibility with various core geometries and overall capabilities are discussed.

Swank, W. David; Carmack, Jon; Werner, James E.; Pink, Robert J.; Haggard, DeLon C.; Johnson, Ryan [Idaho National Laboratory, PO Box 1625, Idaho Falls, ID 83415 (United States)

2007-01-30

112

Not so hot "hot spots" in the oceanic mantle.  

PubMed

Excess volcanism and crustal swelling associated with hot spots are generally attributed to thermal plumes upwelling from the mantle. This concept has been tested in the portion of the Mid-Atlantic Ridge between 34 degrees and 45 degrees (Azores hot spot). Peridotite and basalt data indicate that the upper mantle in the hot spot has undergone a high degree of melting relative to the mantle elsewhere in the North Atlantic. However, application of various geothermometers suggests that the temperature of equilibration of peridotites in the mantle was lower, or at least not higher, in the hot spot than elsewhere. The presence of H(2)O-rich metasomatized mantle domains, inferred from peridotite and basalt data, would lower the melting temperature of the hot spot mantle and thereby reconcile its high degree ofmelting with the lack of a mantle temperature anomaly. Thus, some so-called hot spots might be melting anomalies unrelated to abnormally high mantle temperature or thermal plumes. PMID:17808242

Bonath, E

1990-10-01

113

Hot carrier diffusion in graphene  

E-print Network

We report an optical study of charge transport in graphene. Diffusion of hot carriers in epitaxial graphene and reduced graphene oxide samples are studied using an ultrafast pump-probe technique with a high spatial resolution. Spatiotemporal...

Ruzicka, Brian Andrew; Wang, Shuai; Werake, Lalani Kumari; Weintrub, Ben; Loh, Kian Ping; Zhao, Hui

2010-11-01

114

Delivering hot water more economically.  

PubMed

Jonathan Jones, European product manager at Tyco Thermal Controls, explains the economic and other benefits of using electrically trace-heated single pipe distribution, in place of the more "traditional" flow and return system, for hot water supply. PMID:20527595

Jones, Jonathan

2010-05-01

115

Slip and Dilation Tendency Anlysis of Neal Hot Springs Geothermal Area  

DOE Data Explorer

Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2010; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012; Moeck et al., 2010; Moos and Ronne, 2010 and Reinecker et al., 2005) as well as local stress information if applicable. For faults within these focus systems we applied either a normal faulting stress regime where the vertical stress (sv) is larger than the maximum horizontal stress (shmax) which is larger than the minimum horizontal stress (sv>shmax>shmin) or strike-slip faulting stress regime where the maximum horizontal stress (shmax) is larger than the vertical stress (sv) which is larger than the minimum horizontal stress (shmax >sv>shmin) depending on the general tectonic province of the system. Based on visual inspection of the limited stress magnitude data in the Great Basin we used magnitudes such that shmin/shmax = .527 and shmin/sv= .46, which are consistent with complete and partial stress field determinations from Desert Peak, Coso, the Fallon area and Dixie valley (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2011; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012). Based on inversion of fault kinematic data, Edwards (2013) interpreted that two discrete stress orientations are preserved at Neal Hot Springs. An older episode of east-west directed extension and a younger episode of southwest-northeast directed sinistral, oblique -normal extension. This interpretation is consistent with the evolution of Cenozoic tectonics in the region (Edwards, 2013). As such we applied a southwest-northeast (060) directed normal faulting stress regime, consistent with the younger extensional episode, to the Neal Hot Springs faults. Under these stress conditions northeast striking steeply dipping fault segments have the highest tendency to dilate and northeast striking 60 dipping fault segments have the highest tendency to slip. Under these stress condition...

Faulds, James E.

116

Motion of the Easter hot spot relative to Hawaii and Louisville hot spots  

E-print Network

Motion of the Easter hot spot relative to Hawaii and Louisville hot spots Bernhard Steinberger to the Easter, Hawaii and Louisville hot spots. Computations are performed for a range of different buoyant that a westward motion of the Easter hot spot at several cm per year relative to Hawaii and Louisville hot spots

Steinberger, Bernhard

117

Hot Jupiter Magnetospheres  

NASA Astrophysics Data System (ADS)

The upper atmospheres of close-in gas giant exoplanets ("hot Jupiters") are subjected to intense heating and tidal forces from their parent stars. The atomic (H) and ionized (H+) hydrogen layers are sufficiently rarefied that magnetic pressure may dominate gas pressure for expected planetary magnetic field strength. We examine the structure of the magnetosphere using a 3D isothermal magnetohydrodynamic model that includes a static "dead zone" near the magnetic equator containing gas confined by the magnetic field, a "wind zone" outside the magnetic equator in which thermal pressure gradients and the magneto-centrifugal-tidal effect give rise to a transonic outflow, and a region near the poles where sufficiently strong tidal forces may suppress transonic outflow. Using dipole field geometry, we estimate the size of the dead zone to be several to tens of planetary radii for a range of parameters. Tides decrease the size of the dead zone, while allowing the gas density to increase outward where the effective gravity is outward. In the wind zone, the rapid decrease of density beyond the sonic point leads to smaller densities relative to the neighboring dead zone, which is in hydrostatic equilibrium. To understand the appropriate base conditions for the 3D isothermal model, we compute a simple 1D thermal model in which photoelectric heating from the stellar Lyman continuum is balanced by collisionally excited Ly? cooling. This 1D model exhibits a H layer with temperature T ~= 5000-10,000 K down to a pressure P ~ 10-100 nbar. Using the 3D isothermal model, we compute maps of the H column density as well as the Ly? transmission spectra for parameters appropriate for HD 209458b. Line-integrated transit depths sime5%-10% can be achieved for the above base conditions, in agreement with the results of Koskinen et al. A deep, warm H layer results in a higher mass-loss rate relative to that for a more shallow layer, roughly in proportion to the base pressure. Strong magnetic fields have the effect of increasing the transit signal while decreasing the mass loss, due to higher covering fraction and density of the dead zone. Absorption due to bulk fluid velocity is negligible at linewidths gsim100 km s-1 from line center. In our model, most of the transit signal arises from magnetically confined gas, some of which may be outside the L1 equipotential. Hence, the presence of gas outside the L1 equipotential does not directly imply mass loss. We verify a posteriori that particle mean free paths and ion-neutral drift are small in the region of interest in the atmosphere, and that flux freezing is a good approximation. We suggest that resonant scattering of Ly? by the magnetosphere may be observable due to the Doppler shift from the planet's orbital motion, and may provide a complementary probe of the magnetosphere. Lastly, we discuss the domain of applicability for the magnetic wind model described in this paper as well as the Roche-lobe overflow model.

Trammell, George B.; Arras, Phil; Li, Zhi-Yun

2011-02-01

118

Prometheus Hot Leg Piping Concept  

SciTech Connect

The Naval Reactors Prime Contractor Team (NRPCT) recommended the development of a gas cooled reactor directly coupled to a Brayton energy conversion system as the Space Nuclear Power Plant (SNPP) for NASA's Project Prometheus. The section of piping between the reactor outlet and turbine inlet, designated as the hot leg piping, required unique design features to allow the use of a nickel superalloy rather than a refractory metal as the pressure boundary. The NRPCT evaluated a variety of hot leg piping concepts for performance relative to SNPP system parameters, manufacturability, material considerations, and comparison to past high temperature gas reactor (HTGR) practice. Manufacturability challenges and the impact of pressure drop and turbine entrance temperature reduction on cycle efficiency were discriminators between the piping concepts. This paper summarizes the NRPCT hot leg piping evaluation, presents the concept recommended, and summarizes developmental issues for the recommended concept.

Gribik, Anastasia M. [Bechtel Bettis, Inc., Bettis Atomic Power Laboratory, West Mifflin, PA 15122 (United States); DiLorenzo, Peter A. [KAPL, Inc., Knolls Atomic Power Laboratory, Schenectady, NY 12301 (United States)

2007-01-30

119

Infrared Radiation from Hot Jupiters  

E-print Network

Recent Spitzer infrared (IR) observations of two transiting hot Jupiters during their secondary eclipses have provided the first direct detection of planets orbiting other stars (Charbonneau et al. 2005; Deming et al. 2005). We here elaborate on some aspects of our detection of HD209458b at 24 microns, and we compare to the detection of TrES-1 by Charbonneau et al. Spitzer will eventually determine the IR spectral energy distribution of these and similar hot Jupiters, opening the new field of comparative exoplanetology. For now, we have only three Spitzer data points, augmented by upper limits from the ground. We here interpret the available measurements from a purely observational perspective, and we point out that a blackbody spectrum having T=1100K can account for all current IR measurements, within the errors. This will surely not remain true for long, since ongoing Spitzer observations will be very sensitive to the IR characteristics of hot Jupiters.

Drake Deming; L. Jeremy Richardson; Sara Seager; Joseph Harrington

2005-11-10

120

Archaeal Nitrification in Hot Springs  

NASA Astrophysics Data System (ADS)

Biological nitrification, i.e. the aerobic conversion of ammonia to nitrate via nitrite, is a major component of the global nitrogen cycle. Until recently, it was thought that the ability to aerobically oxidize ammonia was confined to bacteria of the phylum Proteobacteria. However, it has recently been shown that Archaea of the phylum Crenarchaeota are also capable of ammonia oxidation. As many Crenarchaeota are thermophilic or hyperthermophilic, and at least some of them are capable of ammonia oxidation we speculated on the existence of (hyper)thermophilic ammonia-oxidizing archaea (AOA). Using PCR primers specifically targeting the archaeal ammonia monooxygenase (amoA) gene, we were indeed able to confirm the presence of such organisms in several hot springs in Reykjadalur, Iceland. These hot springs exhibited temperatures well above 80 C and pH values ranging from 2.0 to 4.5. To proof that nitrification actually took place under these extreme conditions, we measured gross nitrification rates by the isotope pool dilution method; we added 15N-labelled nitrate to the mud and followed the dilution of the label by nitrate production from ammonium either in situ (incubation in the hot spring) or under controlled conditions in the laboratory (at 80 C). The nitrification rates in the hot springs ranged from 0.79 to 2.22 mg nitrate-N per L of mud and day. Controls, in which microorganisms were killed before the incubations, demonstrated that the nitrification was of biological origin. Addition of ammonium increased the gross nitrification rate approximately 3-fold, indicating that the nitrification was ammonium limited under the conditions used. Collectively, our study provides evidence that (1) AOA are present in hot springs and (2) that they are actively nitrifying. These findings have major implications for our understanding of nitrogen cycling of hot environments.

Richter, A.; Daims, H.; Reigstad, L.; Wanek, W.; Wagner, M.; Schleper, C.

2006-12-01

121

Hot conditioning equipment conceptual design report  

SciTech Connect

This report documents the conceptual design of the Hot Conditioning System Equipment. The Hot conditioning System will consist of two separate designs: the Hot Conditioning System Equipment; and the Hot Conditioning System Annex. The Hot Conditioning System Equipment Design includes the equipment such as ovens, vacuum pumps, inert gas delivery systems, etc.necessary to condition spent nuclear fuel currently in storage in the K Basins of the Hanford Site. The Hot Conditioning System Annex consists of the facility of house the Hot Conditioning System. The Hot Conditioning System will be housed in an annex to the Canister Storage Building. The Hot Conditioning System will consist of pits in the floor which contain ovens in which the spent nuclear will be conditioned prior to interim storage.

Bradshaw, F.W., Westinghouse Hanford

1996-08-06

122

Hot Lingo 2.0  

NSDL National Science Digital Library

This handy little application offers form and applet spell checking for Internet Explorer 5.0 and higher, something that will be useful for persons looking to perform spell-checking in a number of settings and applications. Hot Lingo utilizes a 75,000 word English dictionary, and with this version, users can create a customizable dictionary that contains up to 32,000 additional words. Their Web site also contains a FAQ section, and a place where users can offer feedback on the functionality of the application. Hot Lingo is compatible with all of the Windows operating systems.

123

Hot Gas Halos in Galaxies  

SciTech Connect

We use Chandra and XMM-Newton to study how the hot gas content in early-type galaxies varies with environment. We find that the L{sub X}-L{sub K} relationship is steeper for field galaxies than for comparable galaxies in groups and clusters. This suggests that internal processes such as supernovae driven winds or AGN feedback may expel hot gas from low mass field galaxies. Such mechanisms are less effective in groups and clusters where the presence of an intragroup or intracluster medium may confine outflowing material.

Mulchaey, John S. [Carnegie Observatories (United States); Jeltema, Tesla E. [UCO/Lick Observatories (United States)

2010-06-08

124

Types of Hot Jupiter Atmospheres  

NASA Astrophysics Data System (ADS)

Hot Jupiters, i.e. exoplanet gas giants, having masses comparable to the mass of Jupiter and semimajor axes shorter than 0.1 AU, are a unique class of objects. Since they are so close to the host stars, their atmospheres form and evolve under the action of very active gas dynamical processes caused by the gravitational field and irradiation of the host star. As a matter of fact, the atmospheres of several of these planets fill their Roche lobes , which results in a powerful outflow of material from the planet towards the host star. The energy budget of this process is so important that it almost solely governs the evolution of hot Jupiters gaseous envelopes. Based on the years of experience in the simulations of gas dynamics in mass-exchanging close binary stars, we have investigated specific features of hot Jupiters atmospheres. The analytical estimates and results of 3D numerical simulations, discussed in this Chapter, show that the gaseous envelopes around hot Jupiters may be significantly non-spherical and, at the same time, stationary and long-lived. These results are of fundamental importance for the interpretation of observational data.

Bisikalo, Dmitry V.; Kaygorodov, Pavel V.; Ionov, Dmitry E.; Shematovich, Valery I.

125

Hot air from wood waste  

SciTech Connect

The information of a new range of woodwaste burning hot air stoves from Sacme Murbo, France by Apec control is reported. The stores are suited for small and medium-sized workshops producing sawdust, shavings and offcuts, the range goes from 80,000 Btu/hr to 600,000 Btu/hr.

Not Available

1981-03-21

126

Wireless robots in hot cells  

SciTech Connect

A new method of wireless communication has made it possible for untethered robots to operate freely in hot cells used for reprocessing nuclear fuel. Directional radio waves of very high frequency is used to reduce the reflections to an acceptable level. It also eliminates damaged and tangled robot wires.

Daly, B.

1992-01-01

127

Alpha Gamma Hot Cell Facility  

E-print Network

the hot cell. ARG-US RFID Tags Operate at 433 MHz with >100-m read range House a suite of sensors (seal, shock, temperature, humidity, gamma radiation and neutrons) Feature long battery life (>10 yr) Store with ARG-US RFID System Gamma Dosimeter (top) and Neutron Detector Motherboard and Antenna 10-year Battery

Kemner, Ken

128

Hot Issues at Community Colleges  

NSDL National Science Digital Library

The issues listed on this website are a reflection of AACC's strategic action areas. Their intent is to provide users with a cross-section of important issues surrounding community colleges. These issues will change as the scope and intensity of these issues change. Browse through the list of "hot issues" affecting community colleges today.

2010-06-09

129

Upside's Hot 100 Awards: 1999  

NSDL National Science Digital Library

The business technology magazine Upside Today authors this list of the "hottest private high-tech companies of 1999." Upside editors considered entrepreneurial passion as well as the "staying power" of companies to be top criteria for the Hot 100 Awards. Each listing includes a company profile with homepage links where available.

130

Microsensor Hot-Film Anemometer  

NASA Technical Reports Server (NTRS)

Improved hot-film anemometer developed for making high-bandwidth turbulence measurements in moderate-enthalpy supersonic and hypersonic flows (e.g., NASP inlets and control surfaces, HSCT jet exhaust). Features include low thermal inertia, ruggedness, and reduced perturbation of flow.

Mcginley, Catherine B.; Stephens, Ralph; Hopson, Purnell; Bartlett, James E.; Sheplak, Mark; Spina, Eric F.

1995-01-01

131

Production of hot-wires  

NASA Astrophysics Data System (ADS)

Several methods for producing hot-wire probes are described. Discussion includes the manufacture of probe bodies, soldering plated wires to the prongs etching Walaston type wires, and finishing the probe. This report is written as an instruction manual for researchers who desire to produce or repair their own sensors.

Dickinson, S. C.

1983-04-01

132

Bremsstrahlung of hot quantum plasma  

Microsoft Academic Search

The classical Debye field is replaced by the respective quantum modification for a hot quantum plasma. The bremsstrahlung spectrum and the total bremsstrahlung intensity are investigated in detail. The results of numerical calculations are tabulatedvs. the characteristic parameter=??0 \\/kT, where?0 is the plasma frequency and other symbols have their standard meaning. It is found that the deviations from the bremsstrahlung

J. Kvasnica; J. Horcek

1975-01-01

133

Working in Hot Weather or Hot Workplace Environments Subject: Procedures and Guidelines for Working in Hot Environments  

E-print Network

exhaustion, heat stroke, heat rash, heat cramps and fainting. Hot environment ­ Conditions that challenge is intended to prevent potential heat induced illness as a result of hot weather or hot workplace environments. DEFINITIONS: Acclimatization: Physiological changes which occur in response to several days of heat exposure

Lennard, William N.

134

Hot Flashes amd Night Sweats (PDQ)  

MedlinePLUS

... Dictionary Search for Clinical Trials NCI Publications Espaol Hot Flashes and Night Sweats (PDQ) Overview Key Points ... quality of life in many patients with cancer. Hot flashes and night sweats may be side effects ...

135

Hyperthermia: Too Hot for Your Health  

MedlinePLUS

... Calvin | (301) 496-1752 | nianews3@mail.nih.gov Hot summer weather can pose special health risks to ... places and not understanding how to respond to hot weather conditions. Older people, particularly those with chronic ...

136

Noise Generation in Hot Jets  

NASA Technical Reports Server (NTRS)

A prediction method based on the generalized acoustic analogy is presented, and used to evaluate aerodynamic noise radiated from high speed hot jets. The set of Euler equations are split into their respective non-radiating and residual components. Under certain conditions, the residual equations are rearranged to form a wave equation. This equation consists of a third-order wave operator, plus a number of nonlinear terms that are identified with the equivalent sources of sound and their statistical characteristics are modeled. A specialized RANS solver provides the base flow as well as turbulence quantities and temperature fluctuations that determine the source strength. The main objective here is to evaluate the relative contribution from various source elements to the far-field spectra and to show the significance of temperature fluctuations as a source of aerodynamic noise in hot jets.

Khavaran, Abbas; Kenzakowski, Donald C.

2007-01-01

137

Spectropolarimetry of hot, luminous stars  

NASA Technical Reports Server (NTRS)

I review polarimetric observations of presumably single, hot luminous stars. The stellar types discussed are OB stars. B(e) supergiants, Luminous Blue Variables (LBV), Wolf-Rayet (W-R) stars, and type II supernovae (SN). It is shown that variable, intrinsic polarization is a common phenomenon in that part of the Hertzsprung-Russell (HR) diagram which these stars occupy. However, much observational work remains to be done before we can answer the most basic, statistical questions about the polarimetric properties of different groups of hot, luminous stars. Insight into the diagnostic power of polarization observations has been gained, but cannot be exploited without detailed models. Thus, while polarimetric observations do tell us that the mass-loss processes of all types of massive stars are time-dependent and anisotropic, the significance that this might have for the accuracy of their stellar parameters and evolutionary paths remains elusive.

Schulte-Ladbeck, Regina E.

1994-01-01

138

Hot atom chemistry and radiopharmaceuticals  

SciTech Connect

The chemical products made in a cyclotron target are a combined result of the chemical effects of the nuclear transformation that made the radioactive atom and the bulk radiolysis in the target. This review uses some well-known examples to understand how hot atom chemistry explains the primary products from a nuclear reaction and then how radiation chemistry is exploited to set up the optimal product for radiosynthesis. It also addresses the chemical effects of nuclear decay. There are important principles that are common to hot atom chemistry and radiopharmaceutical chemistry. Both emphasize short-lived radionuclides and manipulation of high specific activity nuclides. Furthermore, they both rely on radiochromatographic separation for identification of no-carrieradded products.

Krohn, Kenneth A.; Moerlein, Stephen M.; Link, Jeanne M.; Welch, Michael J. [University of Washington, Department of Radiology, Molecular Imaging Center, 1959 NE Pacific St., Box 356004, Seattle, WA 98195-6004 (United States); Washington University, Department of Radiology, Division of Radiological Sciences, 510 South Kingshighway, St. Louis, MO 63110 (United States); University of Washington, Department of Radiology, Molecular Imaging Center, 1959 NE Pacific St., Box 356004, Seattle, WA 98195-6004 (United States); Washington University, Department of Radiology, Division of Radiological Sciences, 510 South Kingshighway, St. Louis, MO 63110 (United States)

2012-12-19

139

Double base hot electron transistor  

Microsoft Academic Search

We propose a novel device concept of focusing a hot-electron beam for ballistic injection. Such a focused beam may be achieved by passing injected electrons through a doped semiconductor layer with a built-in electric field. This leads to a more narrow and energy-monochromatic beam. When such a beam is used in ballistic devices, the device performance should significantly improve. As

Jingming Xu; Michael Shur

1988-01-01

140

Hot atoms in cosmic chemistry.  

PubMed

High energy chemical reactions and atom molecule interactions might be important for cosmic chemistry with respect to the accelerated species in solar wind, cosmic rays, colliding gas and dust clouds and secondary knock-on particles in solids. "Hot" atoms with energies ranging from a few eV to some MeV can be generated via nuclear reactions and consequent recoil processes. The chemical fate of the radioactive atoms can be followed by radiochemical methods (radio GC or HPLC). Hot atom chemistry may serve for laboratory simulation of the reactions of energetic species with gaseous or solid interstellar matter. Due to the effective measurement of 10(8)-10(10) atoms only it covers a low to medium dose regime and may add to the studies of ion implantation which due to the optical methods applied are necessarily in the high dose regime. Experimental results are given for the systems: C/H2O (gas), C/H2O (solid, 77 K), N/CH4 (solid, 77K) and C/NH3 (solid, 77 K). Nuclear reactions used for the generation of 2 to 3 MeV atoms are: N(p,alpha) 11C, 16O(p,alpha pn) 11C and 12C(d,n) 13N with 8 to 45 MeV protons or deuterons from a cyclotron. Typical reactions products are: CO, CO2, CH4, CH2O, CH3OH, HCOOH, NH3, CH3NH2, cyanamide, formamidine, guanidine etc. Products of hot reactions in solids are more complex than in corresponding gaseous systems, which underlines the importance of solid state reactions for the build-up of precursors for biomolecules in space. As one of the major mechanisms for product formation, the simultaneous or fast consecutive reactions of a hot carbon with two target molecules (reaction complex) is discussed. PMID:11537799

Rossler, K; Jung, H J; Nebeling, B

1984-01-01

141

Hot and Cold Ideal Gases  

NSDL National Science Digital Library

The EJS Hot and Cold Ideal Gases model simulates the mixing of hot and cold two-dimensional ideal gases in a square box. This simulation can be used as part of the activity described in "The Statistical Interpretation of Entropy: An Activity" by Todd Timberlake, to be published in The Physics Teacher. In the model, one gas is initially confined to the left side of the box while the other gas is confined to the right side. An animation window shows the motion of the particles in the box, while an optional graph window plots the temperature of each side of the box, which is determined by measuring the average KE of the particles on each side. The initial number of particles and temperature on each side of the square can be changed and a button allows the user to reverse the particle velocities at any time. The user can modify this simulation if EJS is installed locally by right-clicking within the plot and selecting "Open Ejs Model" from the pop-up menu item. EJS Hot and Cold Ideal Gases model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_entropy_HotAndColdIdealGases.jar file will run the program if Java is installed. EJS is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional EJS models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or EJS.

Timberlake, Todd

2010-07-01

142

Coping with Hot Work Environments  

E-print Network

Problems Excessive exposure to a hot environment can bring about several physical disorders, including heat stroke, heat exhaustion, heat cramps, fainting, heat rash and momentary or transient heat fatigue. Heat stroke is the most serious heat..., dry and usually red or spot- ted, and the body temperature is 105 degrees F or higher. The person is confused and irritable and may complain of chills. If the victim is not cooled soon, unconsciousness, delirium and convulsions will occur and can...

Smith, David

2005-04-28

143

Lightning Hot Spots in Canada  

NSDL National Science Digital Library

Developed by the Meteorological Service of Canada, this Web site is devoted to lightning phenomena. Occurring 2.7 million times a year in Canada, visitors can find maps of Hot Spots and of current Lightning Activity over Canada. Educators and students can obtain lots of materials dealing with lightning properties, occurrences, and destructive capabilities. The site provides information on lightning activity differences among various geographic regions in Canada. Families can benefit from the high-quality and thorough, Lightning Safety Tips.

144

Hot atoms in cosmic chemistry  

NASA Astrophysics Data System (ADS)

High energy chemical reactions and atom molecule interactions might be important for cosmic chemistry with respect to the accelerated species in solar wind, cosmic rays, colliding gas and dust clouds and secondary knock-on particles in solids. ``Hot'' atoms with energies ranging from a few eV to some MeV can be generated via nuclear reactions and consequent recoil processes. The chemical fate of the radioactive atoms can be followed by radiochemical methods (radio GC or HPLC). Hot atom chemistry may serve for laboratory simulation of the reactions of energetic species with gaseous or solid interstellar matter. Due to the effective measurement of 108-1010 atoms only it covers a low to medium dose regime and may add to the studies of ion implantation which due to the optical methods applied are necessarily in the high dose regime. Experimental results are given for the systems: C/H2O (gas), C/H2O (solid, 77 K), N/CH4 (solid, 77K) and C/NH3 (solid, 77 K). Nuclear reactions used for the generation of 2 to 3 MeV atoms are: 14N(p, ?) 11C, 16O(p, ?pn) 11C and 12C(d,n) 13N with 8 to 45 MeV protons or deuterons from a cyclotron. Typical reactions products are: CO, CO2, CH4, CH2O, CH3OH, HCOOH, NH3, CH3NH2, cyanamide, formamidine, guanidine etc. Products of hot reactions in solids are more complex than in corresponding gaseous systems, which underlines the importance of solid state reactions for the build-up of precursors for biomolecules in space. As one of the major mechanisms for product formation, the simultaneous or fast consecutive reactions of a hot carbon with two target molecules (reaction complex) is discussed.

Rssler, K.; Jung, H.-J.; Nebeling, B.

145

ADVANCED HOT GAS FILTER DEVELOPMENT  

SciTech Connect

Advanced, coal-based power plants will require durable and reliable hot gas filtration systems to remove particulate contaminants from the gas streams to protect downstream components such as turbine blades from erosion damage. It is expected that the filter elements in these systems will have to be made of ceramic materials to withstand goal service temperatures of 1600 F or higher. Recent demonstration projects and pilot plant tests have indicated that the current generation of ceramic hot gas filters (cross-flow and candle configurations) are failing prematurely. Two of the most promising materials that have been extensively evaluated are clay-bonded silicon carbide and alumina-mullite porous monoliths. These candidates, however, have been found to suffer progressive thermal shock fatigue damage, as a result of rapid cooling/heating cycles. Such temperature changes occur when the hot filters are back-pulsed with cooler gas to clean them, or in process upset conditions, where even larger gas temperature changes may occur quickly and unpredictably. In addition, the clay-bonded silicon carbide materials are susceptible to chemical attack of the glassy binder phase that holds the SiC particles together, resulting in softening, strength loss, creep, and eventual failure.

E.S. Connolly; G.D. Forsythe

1998-12-22

146

WISE Discovers Hyperluminous Hot DOGs  

NASA Astrophysics Data System (ADS)

One of the primary science objectives for NASA's Wide-field Infrared Survey Explorer (WISE) is to find the most luminous galaxies in the Universe. We have used WISE photometry to select an extraordinary all-sky sample of galaxies, which are prominent at 12 microns (W3) or 22 microns (W4), but faint or undetected at 3.4 microns (W1) and 4.6 microns (W2). Follow-up observations reveal that most of these galaxies are at redshift > 1.5, that they are hyperluminous (> 10^13 Lsun; with ~10% exceeding 10^14 Lsun, comparable to the most luminous optical QSOs). The follow-up observations also show that they are at least twice as hot as other types of infrared luminous galaxies, so that they are hot dust-obscured-galaxies, or Hot DOGs. Their SEDs have a very high mid-IR to submillimeter luminosity ratio, which is quite different from any existing galaxy templates. They may represent a rare, new phase in the galaxy evolution, possibly hosting extremely powerful super massive black holes.

Eisenhardt, Peter R.; Wu, J.; WISE Team

2013-01-01

147

Hot Accretion With Saturated Conduction  

E-print Network

Observations of the hot gas surrounding Sgr A* and a few other nearby galactic nuclei imply electron and proton mean free paths comparable to the gas capture radius: hot accretion likely proceeds under weakly-collisional conditions in these systems. As a result, thermal conduction, rather than convection, may be important on all scales and affect the global flow properties. The self-similar ADAF solution of Narayan & Yi (1994) is generalized to include a saturated form of thermal conduction, as is appropriate for the weakly-collisional regime of interest. Conduction provides extra heating and yet it reduces the free-free radiative efficiency of the accretion flow (by potentially large factors). These idealized solutions suggest that thermal conduction may be an important physical ingredient to understand hot accretion onto dim accreting black holes. Conduction could also play a role in reducing the rate at which black holes capture ambient gas and in providing an evaporation mechanism for an underlying cold thin disk.

Kristen Menou

2005-07-08

148

ESA uncovers Geminga's `hot spot'  

NASA Astrophysics Data System (ADS)

16 July 2004 Astronomers using ESAs X-ray observatory XMM-Newton have detected a small, bright hot spot on the surface of the neutron star called Geminga, 500 light-years away. The hot spot is the size of a football field and is caused by the same mechanism producing Gemingas X-ray tails. This discovery identifies the missing link between the X-ray and gamma-ray emission from Geminga. hi-res Size hi-res: 1284 kb Credits: ESA, P. Caraveo (IASF, Milan) Geminga's hot spot This figure shows the effects of charged particles accelerated in the magnetosphere of Geminga. Panel (a) shows an image taken with the EPIC instrument on board the XMM-Newton observatory. The bright tails, made of particles kicked out by Gemingas strong magnetic field, trail the neutron star as it moves about in space. Panel (b) shows how electrically charged particles interact with Gemingas magnetic field. For example, if electrons (blue) are kicked out by the star, positrons (in red) hit the stars magnetic poles like in an own goal. Panel (c) illustrates the size of Gemingas magnetic field (blue) compared to that of the star itself at the centre (purple). The magnetic field is tilted with respect to Gemingas rotation axis (red). Panel (d) shows the magnetic poles of Geminga, where charged particles hit the surface of the star, creating a two-million degrees hot spot, a region much hotter than the surroundings. As the star spins on its rotation axis, the hot spot comes into view and then disappears, causing the periodic colour change seen by XMM-Newton. An animated version of the entire sequence can be found at: Click here for animated GIF [low resolution, animated GIF, 5536 KB] Click here for AVI [high resolution, AVI with DIVX compression, 19128 KB] hi-res Size hi-res: 371 kb Credits: ESA, P. Caraveo (IASF, Milan) Geminga's hot spot, panel (a) Panel (a) shows an image taken with the EPIC instrument on board the XMM-Newton observatory. The bright tails, made of particles kicked out by Gemingas strong magnetic field, trail the neutron star as it moves about in space. hi-res Size hi-res: 377 kb Credits: ESA, P. Caraveo (IASF, Milan) Geminga's hot spot, panel (b) Panel (b) shows how electrically charged particles interact with Gemingas magnetic field. For example, if electrons (blue) are kicked out by the star, positrons (red) hit the stars magnetic poles like in an own goal. hi-res Size hi-res: 435 kb Credits: ESA, P. Caraveo (IASF, Milan) Geminga's hot spot, panel (c) Panel (c) illustrates the size of Gemingas magnetic field (blue) compared to that of the star itself at the centre (purple). The magnetic field is tilted with respect to Gemingas rotation axis (red). hi-res Size hi-res: 121 kb Credits: ESA, P. Caraveo (IASF, Milan) Geminga's hot spot, panel (d) Panel (d) shows the magnetic poles of Geminga, where charged particles hit the surface of the star, creating a two-million degree hot spot, a region much hotter than the surroundings. As the star spins on its rotation axis, the hot spot comes into view and then disappears, causing the periodic colour change seen by XMM-Newton. Neutron stars are the smallest kind of stars known. They are the super-dense remnants of massive stars that died in cataclysmic explosions called supernovae. They have been thrown through space like cannonballs and set spinning at a furious rate, with magnetic fields hundreds of billions of times stronger than Earths. In the case of Geminga, this cannonball contains one and a half times the mass of the Sun, squeezed into a sphere just 20 kilometres across and spinning four times every second. A cloud bustling with electrically charged particles surrounds Geminga. These particles are shepherded by its magnetic and electric fields. ESAs XMM-Newton observatory had already discovered that some of these particles are ejected into space, forming tails that stream behind the neutron star as it hurtles along. Scientists did not know whether Gemingas tails are formed by electrons or by their twin particles with an opposite e

2004-07-01

149

Slip and Dilation Tendency Anlysis of Neal Hot Springs Geothermal Area  

SciTech Connect

Slip and Dilation Tendency in focus areas Critically stressed fault segments have a relatively high likelihood of acting as fluid flow conduits (Sibson, 1994). As such, the tendency of a fault segment to slip (slip tendency; Ts; Morris et al., 1996) or to dilate (dilation tendency; Td; Ferrill et al., 1999) provides an indication of which faults or fault segments within a geothermal system are critically stressed and therefore likely to transmit geothermal fluids. The slip tendency of a surface is defined by the ratio of shear stress to normal stress on that surface: Ts = ? / ?n (Morris et al., 1996). Dilation tendency is defined by the stress acting normal to a given surface: Td = (?1-?n) / (?1-?3) (Ferrill et al., 1999). Slip and dilation were calculated using 3DStress (Southwest Research Institute). Slip and dilation tendency are both unitless ratios of the resolved stresses applied to the fault plane by ambient stress conditions. Values range from a maximum of 1, a fault plane ideally oriented to slip or dilate under ambient stress conditions to zero, a fault plane with no potential to slip or dilate. Slip and dilation tendency values were calculated for each fault in the focus study areas at, McGinness Hills, Neal Hot Springs, Patua, Salt Wells, San Emidio, and Tuscarora on fault traces. As dip is not well constrained or unknown for many faults mapped in within these we made these calculations using the dip for each fault that would yield the maximum slip tendency or dilation tendency. As such, these results should be viewed as maximum tendency of each fault to slip or dilate. The resulting along-fault and fault-to-fault variation in slip or dilation potential is a proxy for along fault and fault-to-fault variation in fluid flow conduit potential. Stress Magnitudes and directions Stress field variation within each focus area was approximated based on regional published data and the world stress database (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2010; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012; Moeck et al., 2010; Moos and Ronne, 2010 and Reinecker et al., 2005) as well as local stress information if applicable. For faults within these focus systems we applied either a normal faulting stress regime where the vertical stress (sv) is larger than the maximum horizontal stress (shmax) which is larger than the minimum horizontal stress (sv>shmax>shmin) or strike-slip faulting stress regime where the maximum horizontal stress (shmax) is larger than the vertical stress (sv) which is larger than the minimum horizontal stress (shmax >sv>shmin) depending on the general tectonic province of the system. Based on visual inspection of the limited stress magnitude data in the Great Basin we used magnitudes such that shmin/shmax = .527 and shmin/sv= .46, which are consistent with complete and partial stress field determinations from Desert Peak, Coso, the Fallon area and Dixie valley (Hickman et al., 2000; Hickman et al., 1998 Robertson-Tait et al., 2004; Hickman and Davatzes, 2011; Davatzes and Hickman, 2006; Blake and Davatzes 2011; Blake and Davatzes, 2012). Based on inversion of fault kinematic data, Edwards (2013) interpreted that two discrete stress orientations are preserved at Neal Hot Springs. An older episode of east-west directed extension and a younger episode of southwest-northeast directed sinistral, oblique -normal extension. This interpretation is consistent with the evolution of Cenozoic tectonics in the region (Edwards, 2013). As such we applied a southwest-northeast (060) directed normal faulting stress regime, consistent with the younger extensional episode, to the Neal Hot Springs faults. Under these stress conditions northeast striking steeply dipping fault segments have the highest tendency to dilate and northeast striking 60 dipping fault segments have the highest tendency to slip. Under these stress condition...

Faulds, James E.

2013-12-31

150

How Hot is That Star  

NSDL National Science Digital Library

This resource is part of the Science Education Gateway (SEGway) project, funded by NASA, which is a national consortium of scientists, museums, and educators working together to bring the latest science to students, teachers, and the general public. How hot is the Sun? How do scientists know? Students perform guided Web research through several sites on solar astronomy to answer theses questions, and more: how to measure the temperature of any star, and how astronomers use Hertzsprung-Russell (H-R) diagrams to classify stars by temperature and luminosity. This unit is divided into six lessons, and contains feedback from other educators who have used this module.

Meunier, Jim; Lehman, Jim

151

A Strong Hot Spot Theorem  

SciTech Connect

A real number alpha is said to be b-normal if every m-long string of digits appears in the base-b expansion of alpha with limiting frequency b-m. We prove that alpha is b-normal if and only if it possesses no base-b ''hot spot''. In other words, alpha is b-normal if and only if there is no real number y such that smaller and smaller neighborhoods of y are visited by the successive shifts of the base-b expansion of alpha with larger and larger frequencies, relative to the lengths of these neighborhoods

Bailey, David H.; Misiurewicz, Michal

2005-12-31

152

Hot Flow Anomalies at Venus  

NASA Technical Reports Server (NTRS)

We present a multi-instrument study of a hot flow anomaly (HFA) observed by the Venus Express spacecraft in the Venusian foreshock, on 22 March 2008, incorporating both Venus Express Magnetometer and Analyzer of Space Plasmas and Energetic Atoms (ASPERA) plasma observations. Centered on an interplanetary magnetic field discontinuity with inward convective motional electric fields on both sides, with a decreased core field strength, ion observations consistent with a flow deflection, and bounded by compressive heated edges, the properties of this event are consistent with those of HFAs observed at other planets within the solar system.

Collinson, G. A.; Sibeck, David Gary; Boardsen, Scott A.; Moore, Tom; Barabash, S.; Masters, A.; Shane, N.; Slavin, J.A.; Coates, A.J.; Zhang, T. L.; Sarantos, M.

2012-01-01

153

That's Hot! Robot Brain Programming  

NSDL National Science Digital Library

With the challenge to program computers to mimic the human reaction after touching a hot object, students program LEGO® robots to "react" and move back quickly once their touch sensors bump into something. By relating human senses to electronic sensors used in robots, students see the similarities between the human brain and its engineering counterpart, the computer, and come to better understand the functioning of sensors in both applications. They apply an understanding of the human "stimulus-sensor-coordinator-effector-response" framework to logically understand human and robot actions.

GK-12 Program, Computational Neurobiology Center, College of Engineering,

154

Advanced Hot-Gas Desulfurization Sorbents  

Microsoft Academic Search

Integrated gasification combined cycle (IGCC) power systems are being advanced worldwide for generating electricity from coal due to their superior environmental performance, economics, and efficiency in comparison to conventional coal-based power plants. Hot gas cleanup offers the potential for higher plant thermal efficiencies and lower cost. A key subsystem of hot-gas cleanup is hot-gas desulfurization using regenerable sorbents. Sorbents based

K. Jothimurugesan; S. K. Gangwal; R. Gupta; B. S. Turk

1997-01-01

155

HotBits: Genuine Random Numbers  

NSDL National Science Digital Library

HotBits is a genuine random number generator powered by radioactive decay. Simply click the "Request HotBits" link, and specify how many bytes you would like (up to 2048) and in what form you prefer them. Hexadecimal returns numbers and letters, while C language returns integers. Then click the "Get HotBits" button, and your random numbers will appear on the screen.

Walker, John

2009-10-21

156

Hot Jupiters: Lands of Plenty  

E-print Network

In late August 2005, 80 researchers from more than 15 countries convened for a 4-day conference entitled ``The Tenth Anniversary of 51 Peg b: Status and Prospects for Hot Jupiter Studies''. The meeting was held at l'Observatoire de Haute-Provence, the location of the 1.93-m telescope and ELODIE spectrograph used to discover the planetary companion to 51 Peg roughly 10 years ago. I summarize several dominant themes that emerged from the meeting, including (i) recent improvements in the precision of radial velocity measurements of nearby, Sun-like stars, (ii) the continued value of individual, newly-discovered planets of novel character to expand the parameter space with which the theory must contend, and (iii) the crucial role of space-based observatories in efforts to characterize hot Jupiter planets. I also present the returns of an informal poll of the conference attendees conducted on the last day of the meeting, which may be amusing to revisit a decade hence.

David Charbonneau

2005-11-22

157

Hot Work Procedures The Hot Work reviewing process is established to prevent ignition of combustible and  

E-print Network

Hot Work Procedures Purpose The Hot Work reviewing process is established to prevent ignition contractor control. Responsibilities The hot work review process shall be conducted by the representative of Physical Plant performing welding/cutting tasks. Project coordinators shall review welding/cutting work

de Lijser, Peter

158

Motion of the Easter hot spot relative to Hawaii and Louisville hot spots  

Microsoft Academic Search

Hot spots have been widely used as a fixed reference frame for plate motions; however, it should be expected that the underlying plumes are advected in a dynamic mantle. Here a simple numerical model of hot spot motion due to large-scale mantle flow is applied to the Easter, Hawaii and Louisville hot spots. Computations are performed for a range of

Bernhard Steinberger

2002-01-01

159

ADVANCED HOT GAS FILTER DEVELOPMENT  

SciTech Connect

DuPont Lanxide Composites, Inc. undertook a sixty-month program, under DOE Contract DEAC21-94MC31214, in order to develop hot gas candle filters from a patented material technology know as PRD-66. The goal of this program was to extend the development of this material as a filter element and fully assess the capability of this technology to meet the needs of Pressurized Fluidized Bed Combustion (PFBC) and Integrated Gasification Combined Cycle (IGCC) power generation systems at commercial scale. The principal objective of Task 3 was to build on the initial PRD-66 filter development, optimize its structure, and evaluate basic material properties relevant to the hot gas filter application. Initially, this consisted of an evaluation of an advanced filament-wound core structure that had been designed to produce an effective bulk filter underneath the barrier filter formed by the outer membrane. The basic material properties to be evaluated (as established by the DOE/METC materials working group) would include mechanical, thermal, and fracture toughness parameters for both new and used material, for the purpose of building a material database consistent with what is being done for the alternative candle filter systems. Task 3 was later expanded to include analysis of PRD-66 candle filters, which had been exposed to actual PFBC conditions, development of an improved membrane, and installation of equipment necessary for the processing of a modified composition. Task 4 would address essential technical issues involving the scale-up of PRD-66 candle filter manufacturing from prototype production to commercial scale manufacturing. The focus would be on capacity (as it affects the ability to deliver commercial order quantities), process specification (as it affects yields, quality, and costs), and manufacturing systems (e.g. QA/QC, materials handling, parts flow, and cost data acquisition). Any filters fabricated during this task would be used for product qualification tests being conducted by Westinghouse at Foster-Wheeler's Pressurized Circulating Fluidized Bed (PCFBC) test facility in Karhula, Finland. Task 5 was designed to demonstrate the improvements implemented in Task 4 by fabricating fifty 1.5-meter hot gas filters. These filters were to be made available for DOE-sponsored field trials at the Power Systems Development Facility (PSDF), operated by Southern Company Services in Wilsonville, Alabama.

E.S. Connolly; G.D. Forsythe

2000-09-30

160

Hot topics in functional neuroradiology.  

PubMed

Functional neuroradiology represents a relatively new and ever-growing subspecialty in the field of neuroradiology. Neuroradiology has evolved beyond anatomy and basic tissue signal characteristics and strives to understand the underlying physiologic processes of central nervous system disease. The American Society of Functional Neuroradiology sponsors a yearly educational and scientific meeting, and the educational committee was asked to suggest a few cutting-edge functional neuroradiology techniques (hot topics). The following is a review of several of these topics and includes "Diffusion Tensor Imaging of the Pediatric Spinal Cord"; "Diffusional Kurtosis Imaging"; "From Standardization to Quantification: Beyond Biomarkers toward Bioscales as Neuro MR Imaging Surrogates of Clinical End Points"; Resting-State Functional MR Imaging"; and "Current Use of Cerebrovascular Reserve Imaging." PMID:24136644

Faro, S H; Mohamed, F B; Helpern, J A; Jensen, J H; Thulborn, K R; Atkinson, I C; Sair, H I; Mikulis, D J

2013-12-01

161

TRUEX hot demonstration. Final report  

SciTech Connect

In FY 1987, a program was initiated to demonstrate technology for recovering transuranic (TRU) elements from defense wastes. This hot demonstration was to be carried out with solution from the dissolution of irradiated fuels. This recovery would be accomplished with both PUREX and TRUEX solvent extraction processes. Work planned for this program included preparation of a shielded-cell facility for the receipt and storage of spent fuel from commercial power reactors, dissolution of this fuel, operation of a PUREX process to produce specific feeds for the TRUEX process, operation of a TRUEX process to remove residual actinide elements from PUREX process raffinates, and processing and disposal of waste and product streams. This report documents the work completed in planning and starting up this program. It is meant to serve as a guide for anyone planning similar demonstrations of TRUEX or other solvent extraction processing in a shielded-cell facility.

Chamberlain, D.B.; Leonard, R.A.; Hoh, J.C.; Gay, E.C.; Kalina, D.G.; Vandegrift, G.F.

1990-04-01

162

Ceramic hot-gas filter  

DOEpatents

A ceramic hot-gas candle filter having a porous support of filament-wound oxide ceramic yarn at least partially surrounded by a porous refractory oxide ceramic matrix, and a membrane layer on at least one surface thereof. The membrane layer may be on the outer surface, the inner surface, or both the outer and inner surface of the porous support. The membrane layer may be formed of an ordered arrangement of circularly wound, continuous filament oxide ceramic yarn, a ceramic filler material which is less permeable than the filament-wound support structure, or some combination of continuous filament and filler material. A particularly effective membrane layer features circularly wound filament with gaps intentionally placed between adjacent windings, and a filler material of ceramic particulates uniformly distributed throughout the gap region. The filter can withstand thermal cycling during backpulse cleaning and is resistant to chemical degradation at high temperatures.

Connolly, Elizabeth Sokolinski (Wilmington, DE); Forsythe, George Daniel (Landenberg, PA); Domanski, Daniel Matthew (New Castle, DE); Chambers, Jeffrey Allen (Hockessin, DE); Rajendran, Govindasamy Paramasivam (Boothwyn, PA)

1999-01-01

163

HotSpot Software Test Plan  

SciTech Connect

This Software Test Plan (STP) describes the procedures used to verify and validate that the HotSpot Health Physics Codes meet the requirements of its user base, which includes: (1) Users of the PC version of HotSpot conducting consequence assessment, hazard assessment and safety analysis calculations; and (2) Users of the NARAC Web and iClient software tools, which allow users to run HotSpot for consequence assessment modeling. This plan is intended to meet Critical Recommendation 2 from the Software Evaluation of HotSpot and DOE Safety Software Toolbox Recommendation for inclusion of HotSpot in the Department of Energy (DOE) Safety Software Toolbox. These users and sponsors of the HotSpot software and the organizations they represent constitute the intended audience for this document. HotSpot software is maintained for the Department of Energy Office of Emergency Operations by the National Atmospheric Release Advisory Center (NARAC) at Lawrence Livermore National Laboratory (LLNL). An overview of HotSpot and NARAC are provided.

Walker, H; Homann, S G

2009-03-12

164

HotSpot Software Configuration Management Plan  

SciTech Connect

This Software Configuration Management Plan (SCMP) describes the software configuration management procedures used to ensure that the HotSpot dispersion model meets the requirements of its user base, which includes: (1) Users of the PC version of HotSpot for consequence assessment, hazard assessment and safety analysis calculations; and (2) Users of the NARAC Web and iClient software tools, which allow users to run HotSpot for consequence assessment modeling These users and sponsors of the HotSpot software and the organizations they represent constitute the intended audience for this document. This plan is intended to meet Critical Recommendations 1 and 3 from the Software Evaluation of HotSpot and DOE Safety Software Toolbox Recommendation for inclusion of HotSpot in the Department of Energy (DOE) Safety Software Toolbox. HotSpot software is maintained for the Department of Energy Office of Emergency Operations by the National Atmospheric Release Advisory Center (NARAC) at Lawrence Livermore National Laboratory (LLNL). An overview of HotSpot and NARAC are provided.

Walker, H; Homann, S G

2009-03-12

165

Fracture toughness of hot-pressed beryllium  

NASA Technical Reports Server (NTRS)

This paper presents the results of an investigation into the fracture toughness, sustained-load flaw growth, and fatigue-crack propagation resistance of S200E hot-pressed beryllium at room temperature. It also reviews the literature pertaining to the influence of various factors on the fracture toughness of hot-pressed beryllium determined using fatigue-cracked specimens.

Lemon, D. D.; Brown, W. F., Jr.

1985-01-01

166

Hot Accretion Flows Around Black Holes  

NASA Astrophysics Data System (ADS)

Black hole accretion flows can be divided into two broad classes: cold and hot. Whereas cold accretion flows consist of cool optically thick gas and are found at relatively high mass accretion rates, hot accretion flows, the topic of this review, are virially hot and optically thin, and occur at lower mass accretion rates. They are described by accretion solutions such as the advection-dominated accretion flow and luminous hot accretion flow. Because of energy advection, the radiative efficiency of these flows is in general lower than that of a standard thin accretion disk. Moreover, the efficiency decreases with decreasing mass accretion rate. Observations show that hot accretion flows are associated with jets. In addition, theoretical arguments suggest that hot flows should produce strong winds. Hot accretion flows are believed to be present in low-luminosity active galactic nuclei and in black hole X-ray binaries in the hard and quiescent states. The prototype is Sgr A*, the ultralow-luminosity supermassive black hole at our Galactic center. The jet, wind, and radiation from a supermassive black hole with a hot accretion flow can interact with the external interstellar medium and modify the evolution of the host galaxy.

Yuan, Feng; Narayan, Ramesh

2014-08-01

167

Hot water use at coin laundries  

SciTech Connect

Detailed data on hot water use for one year are presented for two coin laundries. The first is a three-machine laundry that serves half a 50-unit apartment house, and the second is an eight-machine laundry that serves an 82-unit apartment house. For the smaller laundry, the maximum possible demand--i.e., three machines simultaneously filling with hot water--occurred more than once per month. For the larger laundry, the maximum instantaneous demand was equivalent to four machines simultaneously filling with hot water. At this site, the shortest interval in which hot water use equaled that for all eight machines running hot washes was 35 minutes. The data on hot water use for the two laundries were used to validate a methodology for sizing hot water heaters that had been presented at an ASHRAE Symposium. This methodology, which accounts for heating rate, storage capacity, and water temperatures, successfully predicted the conditions when the water heaters would and would not be adequate for the measured loads. The data are an important part of ongoing efforts to characterize the highly diverse universe of hot water use in commercial buildings.

Lowenstein, A.; Hiller, C.C.

1999-07-01

168

STATE OF CALIFORNIA DOMESTIC HOT WATER (DHW)  

E-print Network

STATE OF CALIFORNIA DOMESTIC HOT WATER (DHW) CEC- CF-6R-MECH-01 (Revised 08/09) CALIFORNIA ENERGY COMMISSION INSTALLATION CERTIFICATE CF-6R-MECH-01 Domestic Hot Water (DHW) (Page 1 of 3) Site Address: Enforcement Agency: Permit Number: 2008 Residential Compliance Forms August 2009 1. WATER HEATING SYSTEMS

169

Hot electron transport and current sensing  

Microsoft Academic Search

The effect of hot electrons on momentum scattering rates in a two-dimensional electron gas is critically examined. It is shown that with hot electrons it is possible to explore the temperature dependence of individual scattering mechanisms not easily probed under equilibrium conditions; both the Bloch-Gruneisen (BG) phonon scattering phenomena and the reduction in impurity scattering are clearly observed. The theoretical

Mathew Cheeran Abraham

2004-01-01

170

Hot Dry Rock Geothermal Energy Technology  

NSDL National Science Digital Library

This site helps to explain Hot Dry Rock (HDR) Technology, which harnesses geothermal energy to produce electricity. The website contains images and information about how hot dry rock technology is being used all over the world. The site also provides a list of contacts and additional related websites.

2007-07-20

171

Demonstrating Integrated Pest Management of Hot Peppers  

Technology Transfer Automated Retrieval System (TEKTRAN)

We studied the effects of organic and synthetic chemical fertilizers on crop growth, yield and associated insect pests for two varieties of hot pepper, Capsicum chinense Jacquin (Solanaceae): Scotch Bonnet and Caribbean Red in north Florida. Hot peppers were grown under three treatments: poultr...

172

DEMONSTRATING INTEGRATED PEST MANAGEMENT OF HOT PEPPERS  

Technology Transfer Automated Retrieval System (TEKTRAN)

We studied the effects of organic and synthetic chemical fertilizers on crop growth, yield and associated insect pests for two varieties of hot pepper, Capsicum chinense Jacquin (Solanaceae): Scotch Bonnet and Caribbean Red in north Florida. Hot peppers were grown under three treatments: poultr...

173

The Hot Hand Belief and Framing Effects  

ERIC Educational Resources Information Center

Purpose: Recent evidence of the hot hand in sport--where success breeds success in a positive recency of successful shots, for instance--indicates that this pattern does not actually exist. Yet the belief persists. We used 2 studies to explore the effects of framing on the hot hand belief in sport. We looked at the effect of sport experience and

MacMahon, Clare; Kppen, Jrn; Raab, Markus

2014-01-01

174

Variational Theory of Hot Dense Matter  

ERIC Educational Resources Information Center

We develop a variational theory of hot nuclear matter in neutron stars and supernovae. It can also be used to study charged, hot nuclear matter which may be produced in heavy-ion collisions. This theory is a generalization of the variational theory of cold nuclear and neutron star matter based on realistic models of nuclear forces and pair

Mukherjee, Abhishek

2009-01-01

175

"Hot Tub Rash" and "Swimmer's Ear" (Pseudomonas)  

MedlinePLUS

Facts About Hot Tub Rash and Swimmers Ear (Pseudomonas) What is Pseudomonas and how can it affect me? Pseudomonas (sue-doh- ... a major cause of infections commonly known as hot tub rash and swimmers ear. This germ is ...

176

Karhula hot gas cleanup test results  

Microsoft Academic Search

The objective of this work is to develop a practical hot gas filter design that meets the performance and operational requirements of pressurized fluidized bed combustion--bubbling bed, circulating bed and second generation--applications. The Westinghouse hot gas candle filter system is currently installed in the Ahlstrom Pyropower 10 MW (thermal) pressurized circulating fluidized bed combustor (PCFB) test facility located in Karhula,

T. E. Lippert; G. J. Bruck; J. Isaksson

1994-01-01

177

Turbine Engine Hot Section Technology, 1985  

NASA Technical Reports Server (NTRS)

The Turbine Engine Section Technology (HOST) Project Office of the Lewis Research Center sponsored a workshop to discuss current research pertinent to turbine engine hot section durability problems. Presentations were made concerning hot section environment and the behavior of combustion liners, turbine blades, and turbine vanes.

1985-01-01

178

Impact of substrate injected hot electrons on hot carrier degradation in a 180-nm NMOSFET  

NASA Astrophysics Data System (ADS)

Although hot carriers induced degradation of NMOSFETs has been studied for decades, the role of hot electron in this process is still debated. In this paper, the additional substrate hot electrons have been intentionally injected into the oxide layer to analyze the role of hot electron in hot carrier degradation. The enhanced degradation and the decreased time exponent appear with the injected hot electrons increasing, the degradation increases from 21.80% to 62.00% and the time exponent decreases from 0.59 to 0.27 with Vb decreasing from 0 V to ?4 V, at the same time, the recovery also becomes remarkable and which strongly depends on the post stress gate bias Vg. Based on the experimental results, more unrecovered interface traps are created by the additional injected hot electron from the breaking SiH bond, but the oxide trapped negative charges do not increase after a rapid recovery.

Liang, Bin; Chen, Jian-Jun; Chi, Ya-Qing

2014-11-01

179

Iron Aluminide Hot Gas Filters  

SciTech Connect

Currently, high temperature filter systems are in the demonstration phase with the first commercial scale hot filter systems being installed on integrated gasification combined cycle (IGCC) and pressurized fluid bed combustion cycle (PBFC) systems (70 MW). They are dependent on the development of durable and economic high temperature filter systems. These filters are mostly ceramic tubes or candles. Ceramic filter durability has not been high. Failure is usually attributed to mechanical or thermal shock: they can also undergo significant changes due to service conditions. The overall objective of this project is to commercialize weldable, crack resistant filters which will provide several years service in advanced power processes. The specific objectives of this project are to develop corrosion resistant alloys and manufacturing processes to make Iron Aluminide filter media, and to use a ``short term`` exposure apparatus supported by other tests to identify the most promising candidate (alloy plus sintering cycle). The objectives of the next phases are to demonstrate long term corrosion stability for the best candidate followed by the production of fifty filters (optional).

Hurley, J.; Brosious, S.; Johnson, M. [Pall Process Equipment Development Div., Pall Corp., Cortland, NY (United States)

1996-12-31

180

Outflow from Hot Accretion Flows  

NASA Astrophysics Data System (ADS)

Numerical simulations of hot accretion flows have shown that the mass accretion rate decreases with decreasing radius. Two models have been proposed to explain this result. In the adiabatic inflow-outflow solution (ADIOS), it is thought to be due to the loss of gas in outflows. In the convection-dominated accretion flow (CDAF) model, it is explained as because that the gas is locked in convective eddies. In this paper we use hydrodynamical (HD) and magnetohydrodynamical (MHD) simulations to investigate which one is physical. We calculate and compare various properties of inflow (gas with an inward velocity) and outflow (gas with an outward velocity). Systematic and significant differences are found. For example, for HD flows, the temperature of outflow is higher than inflow; while for MHD flows, the specific angular momentum of outflow is much higher than inflow. We have also analyzed the convective stability of MHD accretion flow and found that they are stable. These results suggest that systematic inward and outward motion must exist, i.e., the ADIOS model is favored. The different properties of inflow and outflow also suggest that the mechanisms of producing outflow in HD and MHD flows are buoyancy associated with the convection and the centrifugal force associated with the angular momentum transport mediated by the magnetic field, respectively. The latter mechanism is similar to the Blandford & Payne mechanism but no large-scale open magnetic field is required here. Possible observational applications are briefly discussed.

Yuan, Feng; Bu, Defu; Wu, Maochun

2013-02-01

181

Hot filament cvd of boron nitride films  

SciTech Connect

This patent describes a method for coating a substrate with a boron nitride film. It comprises: providing a substrate and a hot filament in a gas chamber; and introducing a borazine gas into the gas chamber so as to heat the borazine gas with the hot filament and deposit the boron nitride film on the substrate, wherein the hot filament is heated to a temperature of from about 1000[degrees] to 1800[degrees] C and the substrate is maintained at a temperature of from 100[degrees]C to 400[degrees]C.

Rye, R.R.

1992-01-07

182

Combining seismology and spectropolarimetry of hot stars  

NASA Astrophysics Data System (ADS)

Asteroseismology and spectropolarimetry have allowed us to progress significantly in our understanding of the physics of hot stars over the last decade. It is now possible to combine these two techniques to learn even more information about hot stars and constrain their models. While only a few magnetic pulsating hot stars are known as of today and have been studied with both seismology and spectropolarimetry, new opportunities - in particular Kepler2 and BRITE - are emerging and will allow us to rapidly obtain new combined results.

Neiner, Coralie; Briquet, Maryline; Mathis, Stphane; Degroote, Pieter

2015-01-01

183

Replication of optical components by hot embossing  

NASA Astrophysics Data System (ADS)

Replication technology for microstructures is an essential issue for transforming expensive microstructures to cheap polymer replicas. Hot embossing has proven to be a suitable technology to fulfil the requirements of industrial applications and to fill the gap between the laboratory and the consumer market. Compared to injection moulding, hot embossing creates microstructures with lower internal stress and is therefore highly suitable for the replication of stress sensitive components, as required, e. g., for optical applications. This paper gives an overview over the hot embossing process, the technology, and shows the potential for the replication of optical components and systems.

Worgull, M.; Schneider, M.; Heilig, M.; Kolew, A.; Dinglreiter, H.; Mohr, J.

2010-05-01

184

Hot Jupiter Variability in Eclipse Depth  

E-print Network

Physical conditions in the atmospheres of tidally-locked, slowly-rotating hot Jupiters correspond to dynamical circulation regimes with Rhines scales and Rossby deformation radii comparable to the planetary radii. Consequently, the large spatial scales of moving atmospheric structures could generate significant photospheric variability. Here, we estimate the level of thermal infrared variability expected in successive secondary eclipse depths, according to hot Jupiter turbulent ``shallow-layer'' models. The variability, at the few percent level or more in models with strong enough winds, is within the reach of Spitzer measurements. Eclipse depth variability is thus a valuable tool to constrain the circulation regime and global wind speeds in hot Jupiter atmospheres.

Emily Rauscher; Kristen Menou; James Y-K. Cho; Sara Seager; Brad Hansen

2007-05-03

185

Design data brochure: Solar hot air heater  

NASA Technical Reports Server (NTRS)

The design, installation, performance, and application of a solar hot air heater for residential, commercial and industrial use is reported. The system has been installed at the Concho Indian School in El Reno, Oklahoma.

1978-01-01

186

Hot wire anemometry in transonic flow  

NASA Technical Reports Server (NTRS)

The use of hot-wire anemometry for obtaining fluctuating data in transonic flows has been evaluated. From hot-wire heat loss correlations based on previous transonic data, the sensitivity coefficients for velocity, density, and total temperature fluctuations have been calculated for a wide range of test conditions and sensor parameters. For sensor Reynolds numbers greater than 20 and high sensor overheat ratios, the velocity sensitivity remains independent of Mach number and equal to the density sensitivity. These conclusions were verified by comparisons of predicted sensitivities with those from recent direct calibrations in transonic flows. Based on these results, techniques are presented to obtain meaningful measurements of fluctuating velocity, density, and Reynolds shear stress using hot-wire and hot-film anemometers. Examples of these measurements are presented for two transonic boundary layers.

Horstman, C. C.; Rose, W. C.

1975-01-01

187

Arnold Schwarzenegger WATER HEATERS AND HOT WATER  

E-print Network

Arnold Schwarzenegger Governor WATER HEATERS AND HOT WATER DISTRIBUTION SYSTEMS;#12;Appendices Appendix A. Multifamily Water Heating Construction Practices, Pricing and Availability Survey Report Appendix B. Multifamily Water Heating Controls Performance Field Report Appendix C. Pipe

188

Bouncing Balls and Hot Rod Races.  

ERIC Educational Resources Information Center

This paper presents the Bouncing Ball Experiment which models quadratic and exponential functions, and the Hot Rod Races activity that explores velocity and acceleration. Activities include directions for the use of TI-82 and TI-83 calculators. (YDS)

Tibbs, Peggy; Sherrill, Donna

189

Toward Eclipse Mapping of Hot Jupiters  

E-print Network

Recent Spitzer infrared measurements of hot Jupiter eclipses suggest that eclipse mapping techniques could be used to spatially resolve the day-side photospheric emission of these planets using partial occultations. As a first step in this direction, we simulate ingress/egress lightcurves for the three brightest known eclipsing hot Jupiters and evaluate the degree to which parameterized photospheric emission models can be distinguished from each other with repeated, noisy eclipse measurements. We find that the photometric accuracy of Spitzer is insufficient to use this tool effectively. On the other hand, the level of photospheric details that could be probed with a few JWST eclipse measurements could greatly inform hot Jupiter atmospheric modeling efforts. A JWST program focused on non-parametric eclipse map inversions for hot Jupiters should be actively considered.

Emily Rauscher; Kristen Menou; Sara Seager; Drake Deming; James Y-K. Cho; Brad Hansen

2006-12-14

190

Prototype solar heating and hot water systems  

NASA Technical Reports Server (NTRS)

Progress made in the development of a solar hot water and space heating system is described in four quarterly reports. The program schedules, technical status and other program activities from 6 October 1976 through 30 September 1977 are provided.

1978-01-01

191

Hot electron effect in ultrathin photovoltaic devices  

NASA Astrophysics Data System (ADS)

The focus of the research work described in the following thesis is increasing the efficiency of photovoltaic devices by reducing hot carrier thermalization losses. In principle this can be achieved by reducing the size of the absorber down to lengths comparable to the thermalization length for hot carriers. With the use of ultrathin absorbers hot carrier can be collected before they have reached thermal equilibrium with the lattice. The theoretical work on the subject is comprised of improving the empirical relationship developed in the most recent publication on the topic by. By making the assumption that the energy loss rate fits the exponential decay model, an expression for the energy as a function of absorber thickness was developed. The experimental work consist of fabricating devices with different absorber thicknesses and testing their ability to show change in performance due to collection of hot electrons.

Mihaylov, Deyan Ivov

192

Multiscale approach for modeling hot mix asphalt  

E-print Network

Hot mix asphalt (HMA) is a granular composite material stabilized by the presence of asphalt binder. The behavior of HMA is highly influenced by the microstructure distribution in terms of the different particle sizes present in the mix...

Dessouky, Samer Hassan

2005-08-29

193

The deposition of silica in hot springs  

Microsoft Academic Search

Natural hot spring waters ascending rapidly to the surface become supersaturated with respect to quartz because of rapid cooling,\\u000a separation of steam and sluggish deposition of quartz and other crystallineSiO\\u000a 2 phases. Large amounts of silica are likely to be deposited in hot spring systems only after the solubility of amorphous silica\\u000a has been exceeded. Cristobalite and chaleedony probably form

R. O. Fournier; J. J. Rowe

1966-01-01

194

Sensitivity analysis of hot channel calculation methods  

Microsoft Academic Search

In safety analysis, the fulfillment of acceptance criteria is usually evaluated by separate hot channel or\\/and hot assembly thermal hydraulic\\/fuel behavior calculations. The whole range of the relevant input parameters (e.g. power distributions, burnup, heat conduction data, inlet temperature, etc.) must be taken into account. Concerning these parameters, the most frequent conservative approach is to select the limiting values, partly

I. Panka; M. Telbisz

2007-01-01

195

Hot-Wire Synthesis of Gold Nanoparticles  

Microsoft Academic Search

Gold nanoparticles were synthesized by a hot-wire generator at atmospheric pressure using a gold-platinum composite wire. At low gas flow velocities the nanoparticles were found to be agglomerates of partially sintered primary particles. By reducing the tube size via the insertion of a nozzle with a throat diameter of 3 mm, the hot-wire generator was found to produce small (<10

Adam M. Boies; Pingyan Lei; Steven Calder; Weon Gyu Shin; Steven L. Girshick

2011-01-01

196

Hot Jupiter Radii: A Turbulent History  

NASA Astrophysics Data System (ADS)

Many hot Jupiters, i.e. giant exoplanets with short orbital periods, are bloated, with radii that greatly exceed those of colder gas giants. In models that neglect atmospheric motion, the enhanced irradiation of hot Jupiters is insufficient to explain their large radii. However uneven surface irradiation drives atmospheric circulation. These atmospheric motions deposit heat at deeper layers than irradiation alone, and can explain their large radii. The specific dissipation mechanism for atmospheric circulation can involve a turbulent cascade and/or the driving of electric currents that undergo Ohmic dissipation. The Mechanical Greenhouse model (Youdin & Mitchell, 2010) showed that turbulence in hot Jupiter atmospheres does mechanical work against the stable stratification of upper radiative zones, thereby driving a heat flux deeper into the interior. This poster will describe the first efforts to include this turbulent heat flux in planetary structure models. The goal is to understand the effects of turbulent mixing on hot Jupiter radius evolution. To perform these calculations we modify the publicly available stellar structure code MESA. We show how the effects of turbulence can be included in MESA and understood physically as an effective dissipation profile. We compare the radius evolution of hot Jupiters for different dissipation prescriptions, including our turbulent mixing model and others from the literature. We find that turbulent mixing is an energetically efficient way to explain the bloated radii of hot Jupiters.

Youdin, Andrew N.; Komacek, Thaddeus D.

2014-11-01

197

Rocket engine hot-spot detector  

NASA Astrophysics Data System (ADS)

On high performance devices such as rocket engines it is desirable to know if local hot spots or areas of reduced cooling margin exist. The objective of this program is to design, fabricate and test an electronic hot spot detector capable of sensing local hot spot on the exterior circumference of a regeneratively cooled combustion chamber in order to avoid hardware damage. The electronic hot spot sensor consists of an array of 120 thermocouple elements which are bonded in a flexible belt of polyimide film. The design temperature range is from +30 F to +400 F continuously with an intermittent temperature of 500 F maximum. The thermocouple belt consists of 120 equally spaced copper-Constantan thermocouple junctions which is wrapped around the OMS liquid rocket engine combustion chamber, to monitor temperatures of individual cooling channels. Each thermocouple is located over a cooling channel near the injector end of the combustion chamber. The thermocouple array sensor is held in place by a spring loaded clamp band. Analyses show that in the event of a blocked cooling channel the surface temperature of the chamber over the blocked channel will rise from a normal operating temperature of approx. 300 F to approx. 600 F. The hot spot detector will respond quickly to this change with a response time constant less than 0.05 seconds. The hot spot sensor assembly is fabricated with a laminated construction of layers of Kapton film and an outer protective layer of fiberglass reinforced silicone rubber.

Collamore, F. N.

1985-04-01

198

Disaggregating Hot Water Use and Predicting Hot Water Waste in Five Test Homes  

SciTech Connect

While it is important to make the equipment (or 'plant') in a residential hot water system more efficient, the hot water distribution system also affects overall system performance and energy use. Energy wasted in heating water that is not used is estimated to be on the order of 10 to 30 percent of total domestic hot water (DHW) energy use. This field monitoring project installed temperature sensors on the distribution piping (on trunks and near fixtures) and programmed a data logger to collect data at 5 second intervals whenever there was a hot water draw. This data was used to assign hot water draws to specific end uses in the home as well as to determine the portion of each hot water that was deemed useful (i.e., above a temperature threshold at the fixture). Five houses near Syracuse NY were monitored. Overall, the procedures to assign water draws to each end use were able to successfully assign about 50% of the water draws, but these assigned draws accounted for about 95% of the total hot water use in each home. The amount of hot water deemed as useful ranged from low of 75% at one house to a high of 91% in another. At three of the houses, new water heaters and distribution improvements were implemented during the monitoring period and the impact of these improvements on hot water use and delivery efficiency were evaluated.

Henderson, H.; Wade, J.

2014-04-01

199

ADVANCED HOT GAS FILTER DEVELOPMENT  

SciTech Connect

This report describes the fabrication and testing of continuous fiber ceramic composite (CFCC) based hot gas filters. The fabrication approach utilized a modified filament winding method that combined both continuous and chopped fibers into a novel microstructure. The work was divided into five primary tasks. In the first task, a preliminary set of compositions was fabricated in the form of open end tubes and characterized. The results of this task were used to identify the most promising compositions for sub-scale filter element fabrication and testing. In addition to laboratory measurements of permeability and strength, exposure testing in a coal combustion environment was performed to asses the thermo-chemical stability of the CFCC materials. Four candidate compositions were fabricated into sub-scale filter elements with integral flange and a closed end. Following the 250 hour exposure test in a circulating fluid bed combustor, the retained strength ranged from 70 t 145 percent of the as-fabricated strength. The post-test samples exhibited non-catastrophic failure behavior in contrast to the brittle failure exhibited by monolithic materials. Filter fabrication development continued in a filter improvement and cost reduction task that resulted in an improved fiber architecture, the production of a net shape flange, and an improved low cost bond. These modifications were incorporated into the process and used to fabricate 50 full-sized filter elements for testing in demonstration facilities in Karhula, Finland and at the Power Systems Development Facility (PSDF) in Wilsonville, AL. After 581 hours of testing in the Karhula facility, the elements retained approximately 87 percent of their as-fabricated strength. In addition, mechanical response testing at Virginia Tech provided a further demonstration of the high level of strain tolerance of the vacuum wound filter elements. Additional testing in the M. W. Kellogg unit at the PSDF has accumulated over 1800 hours of coal firing at temperatures of 760 C including a severe thermal upset that resulted in the failure of several monolithic oxide elements. No failures of any kind have been reported for the MTI CFCC elements in either of these test campaigns. Additional testing is planned at the M. W. Kellogg unit and Foster Wheeler unit at the PSDF over the next year in order to qualify for consideration for the Lakeland PCFB. Process scale-up issues have been identified and manufacturing plans are being evaluated to meet the needs of future demand.

RICHARD A. WAGNER

1998-09-04

200

Physiological responses during continuous work in hot dry and hot humid environments in Indians  

NASA Astrophysics Data System (ADS)

Studies have been conducted on six young healthy heat acclimatised Indians to determine the physiological changes in prolonged continuous work in thermally neutral and in hot dry and hot humid environments. Physiological responses in maximal efforts i.e. Vo2 max, VE max and Cf max were noted. In addition, duration in continuous work at three sub-maximal rate of work in three simulated environments were also noted. Physiological responses like Vo2, VE and Cf were noted every 15 minutes of work. Besides these responses, rectal temperature (Tre), mean skin temperature (Ts) and mean sweat rate were also recorded during continuous work. Results indicated a significant decrease in maximum oxygen uptake capacity (Vo2 max) in heat with no change in maximum exercise ventilation (VE max) and maximum cardiac frequency. However, the fall in Vo2 max was more severe in the hot humid environment than in the hot dry climate. Cardiac frequency at fixed oxygen consumption of 1.0, 1.5 and 2.0 l/min was distinctly higher in the hot humid environment than in the hot dry and comfortable temperature. The duration in continuous physical effort in various grades of activities decreased in hot dry environment from that in the-comfortable climate and further decreased significantly in hot humid environment. The highest rate of sweating was observed during work in humid heat. The mean skin temperature (Ts) showed a fall in all the three rates of work in comfortable and hot dry conditions whereas in hot humid environment it showed a linear rise during the progress of work. The rectal temperature on the other hand maintained a near steady state while working at 65 and 82 watts in comfortable and hot dry environments but kept on rising during work in hot humid environment. At the highest work rate of 98 watts, the rectal temperature showed a steady increase even in the hot dry condition. It was thus concluded from the study that a hot humid climate imposes more constraints on the thermoregulatory system during work than in the hot dry condition because of less effective heat dissipation so resulting in reduced tolerance to work.

Sen Gupta, J.; Swamy, Y. V.; Pichan, G.; Dimri, G. P.

1984-06-01

201

Experiments with the hot list strategy  

SciTech Connect

Experimentation strongly suggests that, for attacking deep questions and hard problems with the assistance of an automated reasoning program, the more effective paradigms rely on the retention of deduced information. A significant obstacle ordinarily presented by such a paradigm is the deduction and retention of one or more needed conclusions whose complexity sharply delays their consideration. To mitigate the severity of the cited obstacle, the author formulates and features in this report the hot list strategy. The hot list strategy asks the researcher to choose, usually from among the input statements, one or more clauses that are conjectured to play a key role for assignment completion. The chosen clauses - conjectured to merit revisiting, again and again - are placed in an input list of clauses, called the hot list. When an automated reasoning program has decided to retain a new conclusion C - before any other clause is chosen to initiate conclusion drawing - the presence of a nonempty hot list (with an appropriate assignment of the input parameter known as heat) causes each inference rule in use to be applied to C together with the appropriate number of members of the hot list. Members of the hot list are used to complete applications of inference rules and not to initiate applications. The use of the hot list strategy thus enables an automated reasoning program to briefly consider a newly retained conclusion whose complexity would otherwise prevent its use for perhaps many CPU-hours. To give evidence of the value of the strategy, the author focuses on four contexts: (1) dramatically reducing the CPU time required to reach a desired goal; (2) finding a proof of a theorem that had previously resisted all but the more inventive automated attempts; (3) discovering a proof that is more elegant than previously known; and (4) answering a question that had steadfastly eluded researchers relying on an automated reasoning program.

Wos, L.

1997-10-01

202

Modeling fruit internal heating rates for hot air and hot water treatments  

Microsoft Academic Search

Hot air and hot water heating methods have been extensively studied as thermal treatments to control insect pests in fruits to replace chemical fumigation. An inherent difficulty in using these methods is that slow heating rates may result in long treatment times and possible damage to fruit quality. Many factors influence heating time. A systematic analysis of those influences is

S. Wang; J. Tang; R. P. Cavalieri

2001-01-01

203

A&M. Hot cell annex (TAN633) interior under construction. Hot cells ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

A&M. Hot cell annex (TAN-633) interior under construction. Hot cells and their doors are along concrete wall. Note side wall of pumice block. Photographer: Jack L. Anderson. Date: October 28, 1957. INEEL negative no. 57-5335 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

204

Hot Water DJ: Saving Energy by Pre-mixing Hot Water Md Anindya Prodhan  

E-print Network

Hot Water DJ: Saving Energy by Pre-mixing Hot Water Md Anindya Prodhan Department of Computer University of Virginia whitehouse@virginia.edu Abstract After space heating and cooling, water heating consumption. Current water heating systems waste up to 20% of their energy due to poor insulation in pipes

Whitehouse, Kamin

205

Metamaterial perfect absorber based hot electron photodetection.  

PubMed

While the nonradiative decay of surface plasmons was once thought to be only a parasitic process that limits the performance of plasmonic devices, it has recently been shown that it can be harnessed in the form of hot electrons for use in photocatalysis, photovoltaics, and photodetectors. Unfortunately, the quantum efficiency of hot electron devices remains low due to poor electron injection and in some cases low optical absorption. Here, we demonstrate how metamaterial perfect absorbers can be used to achieve near-unity optical absorption using ultrathin plasmonic nanostructures with thicknesses of 15 nm, smaller than the hot electron diffusion length. By integrating the metamaterial with a silicon substrate, we experimentally demonstrate a broadband and omnidirectional hot electron photodetector with a photoresponsivity that is among the highest yet reported. We also show how the spectral bandwidth and polarization-sensitivity can be manipulated through engineering the geometry of the metamaterial unit cell. These perfect absorber photodetectors could open a pathway for enhancing hot electron based photovoltaic, sensing, and photocatalysis systems. PMID:24837991

Li, Wei; Valentine, Jason

2014-06-11

206

Extracting hot carriers from photoexcited semiconductor nanocrystals  

SciTech Connect

This research program addresses a fundamental question related to the use of nanomaterials in solar energy -- namely, whether semiconductor nanocrystals (NCs) can help surpass the efficiency limits, the so-called Shockley-Queisser limit, in conventional solar cells. In these cells, absorption of photons with energies above the semiconductor bandgap generates hot charge carriers that quickly cool to the band edges before they can be utilized to do work; this sets the solar cell efficiency at a limit of ~31%. If instead, all of the energy of the hot carriers could be captured, solar-to-electric power conversion efficiencies could be increased, theoretically, to as high as 66%. A potential route to capture this energy is to utilize semiconductor nanocrystals. In these materials, the quasi-continuous conduction and valence bands of the bulk semiconductor become discretized due to confinement of the charge carriers. Consequently, the energy spacing between the electronic levels can be much larger than the highest phonon frequency of the lattice, creating a phonon bottleneck wherein hot-carrier relaxation is possible via slower multiphonon emission. For example, hot-electron lifetimes as long as ~1 ns have been observed in NCs grown by molecular beam epitaxy. In colloidal NCs, long lifetimes have been demonstrated through careful design of the nanocrystal interfaces. Due to their ability to slow electronic relaxation, semiconductor NCs can in principle enable extraction of hot carriers before they cool to the band edges, leading to more efficient solar cells.

Zhu, Xiaoyang

2014-12-10

207

Tests of fixity of the Indo-Atlantic hot spots relative to Pacific hot spots  

NASA Astrophysics Data System (ADS)

of inter-hot spot motion have been debated for decades. Herein we present updated predictions for the tracks of the Tristan da Cunha, Runion, and Iceland hot spots assuming them to be fixed relative to Pacific hot spots. Uncertainties in Pacific hot spot rotations, which include uncertainties in the current locations of hot spots of 100-200 km, are combined with uncertainties in relative plate motions accumulated through the plate circuit to obtain the final uncertainty in the predicted positions (including uncertainties of 150-200 km in the current locations of the Indo-Atlantic hot spots). Improvements to reconstruction methods, to relative plate reconstructions, to age dates along the tracks, and to the geomagnetic reversal timescale lead to significant changes from prior results. When compared with the observed tracks, the predicted tracks indicate nominal rates of motion of only 2-6 mm a-1 of these Indo-Atlantic hot spots relative to Pacific hot spots over the past 48 Ma. Within the uncertainties, the rates range from no motion to rates as high as 8-13 mm a-1. For reconstructions prior to 48 Ma B.P., however, the apparent rates of inter-hot spot motion are much larger, 46-55 20 mm a-1, if the motion occurred entirely between 68 Ma B.P. and 48 Ma B.P. Either hot spots moved rapidly before 48 Ma B.P., and slowed drastically at ? 48 Ma B.P., or global plate circuits through Antarctica become less reliable as one goes increasingly further into the past. Most paleomagnetic data favor the latter explanation.

Koivisto, Emilia A.; Andrews, David L.; Gordon, Richard G.

2014-01-01

208

Molecular interfaces for plasmonic hot electron photovoltaics.  

PubMed

The use of self-assembled monolayers (SAMs) to improve and tailor the photovoltaic performance of plasmonic hot-electron Schottky solar cells is presented. SAMs allow the simultaneous control of open-circuit voltage, hot-electron injection and short-circuit current. To that end, a plurality of molecule structural parameters can be adjusted: SAM molecule's length can be adjusted to control plasmonic hot electron injection. Modifying SAMs dipole moment allows for a precise tuning of the open-circuit voltage. The functionalization of the SAM can also be selected to modify short-circuit current. This allows the simultaneous achievement of high open-circuit voltages (0.56 V) and fill-factors (0.58), IPCE above 5% at the plasmon resonance and maximum power-conversion efficiencies of 0.11%, record for this class of devices. PMID:25578026

Pelayo Garca de Arquer, F; Mihi, Agustn; Konstantatos, Gerasimos

2015-01-28

209

Seeded hot dark matter models with inflation  

NASA Technical Reports Server (NTRS)

We examine massive neutrino (hot dark matter) models for large-scale structure in which the density perturbations are produced by randomly distributed relic seeds and by inflation. Power spectra, streaming velocities, and the Sachs-Wolfe quadrupole fluctuation are derived for this model. We find that the pure seeded hot dark matter model without inflation produces Sachs-Wolfe fluctuations far smaller than those seen by COBE. With the addition of inflationary perturbations, fluctuations consistent with COBE can be produced. The COBE results set the normalization of the inflationary component, which determines the large-scale (about 50/h Mpc) streaming velocities. The normalization of the seed power spectrum is a free parameter, which can be adjusted to obtain the desired fluctuations on small scales. The power spectra produced are very similar to those seen in mixed hot and cold dark matter models.

Gratsias, John; Scherrer, Robert J.; Steigman, Gary; Villumsen, Jens V.

1993-01-01

210

Radioactive hot cell access hole decontamination machine  

DOEpatents

Radioactive hot cell access hole decontamination machine. A mobile housing has an opening large enough to encircle the access hole and has a shielding door, with a door opening and closing mechanism, for uncovering and covering the opening. The housing contains a shaft which has an apparatus for rotating the shaft and a device for independently translating the shaft from the housing through the opening and access hole into the hot cell chamber. A properly sized cylindrical pig containing wire brushes and cloth or other disks, with an arrangement for releasably attaching it to the end of the shaft, circumferentially cleans the access hole wall of radioactive contamination and thereafter detaches from the shaft to fall into the hot cell chamber.

Simpson, William E. (Richland, WA)

1982-01-01

211

MAGNETIC DRAG ON HOT JUPITER ATMOSPHERIC WINDS  

SciTech Connect

Hot Jupiters, with atmospheric temperatures T {approx}> 1000 K, have residual thermal ionization levels sufficient for the interaction of ions with the planetary magnetic field to result in a sizable magnetic drag on the (neutral) atmospheric winds. We evaluate the magnitude of magnetic drag in a representative three-dimensional atmospheric model of the hot Jupiter HD 209458b and find that it is a plausible mechanism to limit wind speeds in this class of atmospheres. Magnetic drag has a strong geometrical dependence, both meridionally and from the dayside to the nightside (in the upper atmosphere), which could have interesting consequences for the atmospheric flow pattern. By extension, close-in eccentric planets with transiently heated atmospheres will experience time-variable levels of magnetic drag. A robust treatment of magnetic drag in circulation models for hot atmospheres may require iterated solutions to the magnetic induction and Saha equations as the hydrodynamic flow is evolved.

Perna, Rosalba [JILA and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Menou, Kristen; Rauscher, Emily [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)

2010-08-20

212

Warm Jupiters as failed hot Jupiters  

NASA Astrophysics Data System (ADS)

The orbits of hot Jupiters often have surprisingly small semi-major axes, large eccentricities, or severe misalignments between their normals and their host stars' spin axes. In some formation scenarios invoking Kozai-Lidov oscillations, an external planetary companion drives a planet onto an orbit having these properties. The mutual inclinations for Kozai-Lidov oscillations can be large and have not been confirmed observationally. Here I present evidence for a population of eccentric warm Jupiters with eccentric giant companions with mutual inclinations just above 40 degrees. These planets may be undergoing a stalled version of tidal migration that produces warm Jupiters over hot Jupiters. I conclude by assessing the contribution of this mechanism to the overall population of short-period hot Jupiters, super-Earths, and mini-Neptunes.

Dawson, Rebekah Ilene; Chiang, Eugene

2015-01-01

213

Mapping the Atmospheres of Hot Jupiters  

E-print Network

We present the results of recent observations of phase-dependent variations in brightness designed to characterize the atmospheres of hot Jupiters. In particular, we focus on recent observations of the transiting planet HD 189733b at 8 micron using the Spitzer Space Telescope, which allow us to determine the efficiency of the day-night circulation on this planet and estimate the longitudinal positions of hot and cold regions in the atmosphere. We discuss the implications of these observations in the context of two other successful detections of more sparsely-sampled phase variations for the non-transiting systems upsilon And b and HD 179949b, which imply a potential diversity in the properties of the atmospheres of hot Jupiters. Lastly, we highlight several upcoming Spitzer observations that will extend this sample to additional wavelengths and more transiting systems in the near future.

H. A. Knutson

2007-10-16

214

Magnetohydrodynamic Simulations of Hot Jupiter Thermospheres  

NASA Astrophysics Data System (ADS)

The majority of models of atmospheric escape from hot Jupiters have focused on one-dimensional, spherically-symmetric models. We present the results from 2-dimensional axisymmetric simulations of hot Jupiters including tidal gravity and magnetic fields as well as photo-ionization and photoelectric heating due to multiple atomic species. Escape is suppressed in polar and equatorial regions by tidal gravity and magnetic fields, respectively, reducing mass-loss estimates achieved through 1-dimensional models. For sufficiently large magnetic field strengths, an equatorial magnetic dead zone creates a static reservoir of hot gas extending to multiple planetary radii and exhibiting temperatures hotter than found within the escaping gas. The possibility of observing this reservoir of gas is discussed, as well as the influence of heavy atoms on the result.

Christie, Duncan; Arras, Phil; Li, Zhi-Yun

2015-01-01

215

New sources for the hot oxygen geocorona  

NASA Technical Reports Server (NTRS)

This paper investigates new sources of thermospheric non thermal (hot) oxygen due to exothermic reactions involving numerous minor (ion and neutral) and metastable species. Numerical calculations are performed for low altitude, daytime, winter conditions, with moderately high solar activity and low magnetic activity. Under these conditions we find that the quenching of metastable species are a significant source of hot oxygen, with kinetic energy production rates a factor of ten higher than those due to previously considered O2(+) and NO(+) dissociative recombination reactions. Some of the most significant new sources of hot oxygen are reactions involving quenching of O(+)((sup 2)D), O((sup 1)D), N((sup 2)D), O(+)((sup 2)P) and vibrationally excited N2 by atomic oxygen.

Richards, P. G.; Hickey, M. P.; Torr, D. G.

1994-01-01

216

Degenerate stars. XII - Recognition of hot nondegenerates  

NASA Astrophysics Data System (ADS)

Fifty-one newly observed degenerate stars and 14 nondegenerates include 13 faint red stars, most of which do not show any lines except DF, Gr 554. Hot subdwarfs and an X-ray source are discussed along with the problem of low-resolution spectroscopic classification of dense hot stars. The multichannel spectrum of the carbon-rich magnetic star LP 790-29 is examined by fitting the undisturbed parts of the spectrum to a black body of 7625 K by the least squares method; the Swan bands absorb 600 A of the spectrum assuming that the blocked radiation is redistributed in the observed region.

Greenstein, J. L.

1980-12-01

217

Evolution of Hot Gas in Elliptical Galaxies  

NASA Technical Reports Server (NTRS)

This theory grant was awarded to study the curious nature, origin and evolution of hot gas in elliptical galaxies and their surrounding groups. Understanding the properties of this X-ray emitting gas has profound implications over the broad landscape of modern astrophysics: cosmology, galaxy formation, star formation, cosmic metal enrichment, galactic structure and dynamics, and the physics of hot gases containing dust and magnetic fields. One of our principal specific objectives was to interpret the marvelous new observations from the XMM and Chandru satellite X-ray telescopes.

Mathews, William G.

2004-01-01

218

Origin and pulsation of hot subdwarfs  

NASA Astrophysics Data System (ADS)

We briefly introduce hot subdwarfs and their evolutionary status before discussing the different types of known pulsators in more detail. Currently, at least six apparently distinct types of variable are known among hot subdwarfs, encompassing p- as well as g-mode pulsators and objects in the Galactic field as well as in globular clusters. Most of the oscillations detected can be explained in terms of an iron opacity mechanism, and quantitative asteroseismology has been very successful for some of the pulsators. In addition to helping constrain possible evolutionary scenarios, studies focussing on stellar pulsations have also been used to infer planets and characterize the rotation of the host star.

Randall, S. K.; Fontaine, G.; Charpinet, S.; Van Grootel, V.; Brassard, P.

2014-02-01

219

Controlled-Temperature Hot-Air Gun  

NASA Technical Reports Server (NTRS)

Materials that find applications in wind tunnels first tested in laboratory. Hot-Air Gun differs from commercial units in that flow rate and temperature monitored and controlled. With typical compressed-airsupply pressure of 25 to 38 psi (170 to 260 kPa), flow rate and maximum temperature are 34 stdft3/min (0.96 stdm3/min) and 1,090 degrees F (590 degrees C), respectively. Resembling elaborate but carefully regulated hot-air gun, setup used to apply blasts of air temperatures above 1,500 degrees F (815 degrees C) to test specimens.

Munoz, M. C.

1986-01-01

220

Hot-spot reaction in unsustained shocks  

SciTech Connect

Shock waves in reactive media create hot spots which undergo further temperature change (following creation) by means of (1) chemical reaction, (2) thermal conduction, and (3) adiabatic effects resulting from pressure variation. A thermodynamic description of exothermic reaction under conditions of variable pressure is presented here. The reaction rate is assumed to be a function of temperature only, and of the Arrhenius form: the effect of variable pressure enters through its influence on temperature. Decreasing pressure significantly alters adiabatic thermal explosion times, and can, under nominal conditions, completely inhibit hot-spot reaction. This effect is discussed in terms of explosive initiation by unsustained shock waves. 7 refs., 2 figs.

Johnson, J.N.

1987-01-01

221

EVOLUTION OF OHMICALLY HEATED HOT JUPITERS  

SciTech Connect

We present calculations of thermal evolution of hot Jupiters with various masses and effective temperatures under ohmic dissipation. The resulting evolutionary sequences show a clear tendency toward inflated radii for effective temperatures that give rise to significant ionization of alkali metals in the atmosphere, compatible with the trend of the data. The degree of inflation shows that ohmic dissipation along with the likely variability in heavy element content can account for all of the currently detected radius anomalies. Furthermore, we find that in the absence of a massive core, low-mass hot Jupiters can overflow their Roche lobes and evaporate on Gyr timescales, possibly leaving behind small rocky cores.

Batygin, Konstantin; Stevenson, David J. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Bodenheimer, Peter H., E-mail: kbatygin@gps.caltech.edu [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)

2011-09-01

222

Validation of the Hot Strip Mill Model  

SciTech Connect

The Hot Strip Mill Model (HSMM) is an off-line, PC based software originally developed by the University of British Columbia (UBC) and the National Institute of Standards and Technology (NIST) under the AISI/DOE Advanced Process Control Program. The HSMM was developed to predict the temperatures, deformations, microstructure evolution and mechanical properties of steel strip or plate rolled in a hot mill. INTEG process group inc. undertook the current task of enhancing and validating the technology. With the support of 5 North American steel producers, INTEG process group tested and validated the model using actual operating data from the steel plants and enhanced the model to improve prediction results.

Richard Shulkosky; David Rosberg; Jerrud Chapman

2005-03-30

223

Cooling of hot electrons in amorphous silicon  

SciTech Connect

Measurements of the cooling rate of hot carriers in amorphous silicon are made with a two-pump, one-probe technique. The experiment is simulated with a rate-equation model describing the energy transfer between a population of hot carriers and the lattice. An energy transfer rate proportional to the temperature difference is found to be consistent with the experimental data while an energy transfer independent of the temperature difference is not. This contrasts with the situation in crystalline silicon. The measured cooling rates are sufficient to explain the difficulty in observing avalanche effects in amorphous silicon.

Vanderhaghen, R.; Hulin, D.; Cuzeau, S.; White, J.O.

1997-07-01

224

Simulations of Hot Bubbles in the ICM  

E-print Network

We review the general properties of the intracluster medium (ICM) in clusters that host a cooling flow, and in particular the effects on the ICM of the injection of hot plasma by a powerful active galactic nucleus (AGN). It is observed that, in some cases, the hot plasma produces cavities in the ICM that finally detach and rise, perhaps buoyantly. The gas dynamics induced by the rising bubbles can help explain the absence of a cooled gas component in clusters with a cooling flow. This scenario is explored using numerical simulations.

A. Gardini; P. M. Ricker

2004-09-15

225

What's Hot in Yellowstone National Park  

NSDL National Science Digital Library

In this activity, learners discover new perspectives on geothermal features, such as geysers, mudpots, hot springs, and hot spring terraces by exploring infrared images. Learners will gain an understanding of infrared light and infrared imaging, as well as, deepen their content knowledge on geothermal features. This lesson features background information for the teacher, background information for students, a mini-exploration of Infrared Image Technology, image sets, assessment information, student worksheets, extension and transfer activities, and additional resources. This is lesson 2 on the Infrared Yellowstone website.

226

Hot dry rock venture risks investigation:  

SciTech Connect

This study assesses a promising resource in central Utah as the potential site of a future commerical hot dry rock (HDR) facility for generating electricity. The results indicate that, if the HDR reservoir productivity equals expectations based on preliminary results from research projects to date, a 50 MWe HDR power facility at Roosevelt Hot Springs could generate power at cost competitive with coal-fired plants. However, it is imperative that the assumed productivity be demonstrated before funds are committed for a commercial facility. 72 refs., 39 figs., 38 tabs.

Not Available

1988-01-01

227

Hot Stars in the Galactic Halo  

NASA Astrophysics Data System (ADS)

Participants; Preface; Foreword; Acknowledgements; Part I. Introductory Papers: 1. What is the galaxy's halo population?; 2. Theoretical properties of horizontal-branch stars; 3. A review of A-type horizontal-branch stars; Part II. Surveys: 4. A progress report on the Edinburgh-Cape object survey; 5. A 300 square degree survey of young stars at high galactic latitudes; 6. The isolation of a new sample of B stars in the halo; 7. A northern catalog of FHB/A stars; 8. Recent progress on a continuing survey of galactic globular clusters for blue stragglers; 9. UV observations with FAUST and the galactic model; 10. Hot stars at the South Galactic Pole; Part III. Clusters: 11. Population II horizontal branches: a photometric study of globular clusters; 12. The period-shift effect in Oosterhoff type II globular clusters; 13. UV photometry of hot stars in omega centauri; 14. Spectroscopic and UBV observations of blue stars at the NGP; 15. Population I horizontal branches: probing the halo-to-disk transition; Part IV. Stars: 16. Very hot subdwarf O stars; 17. Quantitative spectroscopy of the very hot subluminous O-stars: K646, PG1159-035, and KPD0005+5106; 18. Analyzing the helium-rich hot sdO stars in the Palomar Green Survey; 19. Late type companions of hot sd O stars; 20. Hot stars in globular clusters; 21. Faint blue stars from the Hamburg Schmidt Survey; 22. Stellar winds and the evolution of sdB's to sdO's; 23. Halo stars in the Vilnius photometric system; 24. Horizontal branch stars in the geneva photometric system; 25. Zeeman observations of FHB stars and hot subdwarf stars; 26. What does a FHB star's spectrum look like?; 27. A technique for distinguishing FHB stars from A-type stars; 28. eEemental abundances of halo A and interloper stars; 29. The mass of blue horizontal branch stars in the globular cluster NGC6397; 30. IUE observations of blue HB stars in the globular clusters M3 and NGC6752; 31. Metallicities and kinematics of the local RR lyraes: lukewarm stars in the halo; 32. Baade-Wesselink analyses of field vs. cluster RR lyrae variables; 33. The rotation of population II A stars; 34. Horizontal branch stars and possibly related objects; 35. A new group of post-AGB objects - the hot carbon-poor stars; 36. MK classifications of hot stars in the halo 37. Photometry of XX Virginis and V716 Ophiuchi and the period luminosity relations of type II cepheids; 38. Rotation and oxygen line strengths in blue horizontal branch stars; Part V. Miscellaneous: 39. UBV CCd photometry of the halo of M31; 40. Can stars still form in the galactic halo?; 41. The ultraviolet imaging telescope on the Astro -1 and Astro -2 missions; 42. Are analogues of hot subdwarf stars responsible for the UVX phenomenon in galaxy nucleli; 43. A survey for field BHB stars outside the solar circle; 44. Post-AGB A and F supergiants as standard candles; 45. The extended horizontal-branch: a challenge for stellar evolution theory; 46. Astronomical patterns in fractals: the work of A. G. Davis Philip on the Mandelbrot Set; Part VI. Summary: 47. Final remarks; Author index; Subject index.

Adelman, Saul J.; Upgren, Arthur R.; Adelman, Carol J.

2011-03-01

228

Hot Stars in the Galactic Halo  

NASA Astrophysics Data System (ADS)

Participants; Preface; Foreword; Acknowledgements; Part I. Introductory Papers: 1. What is the galaxy's halo population?; 2. Theoretical properties of horizontal-branch stars; 3. A review of A-type horizontal-branch stars; Part II. Surveys: 4. A progress report on the Edinburgh-Cape object survey; 5. A 300 square degree survey of young stars at high galactic latitudes; 6. The isolation of a new sample of B stars in the halo; 7. A northern catalog of FHB/A stars; 8. Recent progress on a continuing survey of galactic globular clusters for blue stragglers; 9. UV observations with FAUST and the galactic model; 10. Hot stars at the South Galactic Pole; Part III. Clusters: 11. Population II horizontal branches: a photometric study of globular clusters; 12. The period-shift effect in Oosterhoff type II globular clusters; 13. UV photometry of hot stars in omega centauri; 14. Spectroscopic and UBV observations of blue stars at the NGP; 15. Population I horizontal branches: probing the halo-to-disk transition; Part IV. Stars: 16. Very hot subdwarf O stars; 17. Quantitative spectroscopy of the very hot subluminous O-stars: K646, PG1159-035, and KPD0005+5106; 18. Analyzing the helium-rich hot sdO stars in the Palomar Green Survey; 19. Late type companions of hot sd O stars; 20. Hot stars in globular clusters; 21. Faint blue stars from the Hamburg Schmidt Survey; 22. Stellar winds and the evolution of sdB's to sdO's; 23. Halo stars in the Vilnius photometric system; 24. Horizontal branch stars in the geneva photometric system; 25. Zeeman observations of FHB stars and hot subdwarf stars; 26. What does a FHB star's spectrum look like?; 27. A technique for distinguishing FHB stars from A-type stars; 28. eEemental abundances of halo A and interloper stars; 29. The mass of blue horizontal branch stars in the globular cluster NGC6397; 30. IUE observations of blue HB stars in the globular clusters M3 and NGC6752; 31. Metallicities and kinematics of the local RR lyraes: lukewarm stars in the halo; 32. Baade-Wesselink analyses of field vs. cluster RR lyrae variables; 33. The rotation of population II A stars; 34. Horizontal branch stars and possibly related objects; 35. A new group of post-AGB objects - the hot carbon-poor stars; 36. MK classifications of hot stars in the halo 37. Photometry of XX Virginis and V716 Ophiuchi and the period luminosity relations of type II cepheids; 38. Rotation and oxygen line strengths in blue horizontal branch stars; Part V. Miscellaneous: 39. UBV CCd photometry of the halo of M31; 40. Can stars still form in the galactic halo?; 41. The ultraviolet imaging telescope on the Astro -1 and Astro -2 missions; 42. Are analogues of hot subdwarf stars responsible for the UVX phenomenon in galaxy nucleli; 43. A survey for field BHB stars outside the solar circle; 44. Post-AGB A and F supergiants as standard candles; 45. The extended horizontal-branch: a challenge for stellar evolution theory; 46. Astronomical patterns in fractals: the work of A. G. Davis Philip on the Mandelbrot Set; Part VI. Summary: 47. Final remarks; Author index; Subject index.

Adelman, Saul J.; Upgren, Arthur R.; Adelman, Carol J.

1994-08-01

229

Kiln for hot-pressing compacts in a continuous manner  

DOEpatents

The invention is directed to a hot pressing furnace or kiln which is capable of preheating, hot pressing, and cooling a plurality of articles in a sequential and continuous manner. The hot pressing furnace of the present invention comprises an elongated, horizontally disposed furnace capable of holding a plurality of displaceable pusher plates each supporting a die body loaded with refractory or ceramic material to be hot pressed. Each of these plates and the die body supported thereby is sequentially pushed through the preheating zone, a temperature stabilizing and a hot pressing zone, and a cooling zone so as to provide a continuous hot-pressing operation of a plurality of articles.

Reynolds, C.D Jr.

1983-08-08

230

Kiln for hot-pressing compacts in a continuous manner  

DOEpatents

The present invention is directed to a hot pressing furnace or kiln which is capable of preheating, hot pressing, and cooling a plurality of articles in a sequential and continuous manner. The hot pressing furnace of the present invention comprises an elongated, horizontally disposed furnace capable of holding a plurality of displaceable pusher plates each supporting a die body loaded with refractory or ceramic material to be hot pressed. Each of these plates and the die body supported thereby is sequentially pushed through the preheating zone, a temperature stabilizing and a hot pressing zone, and a cooling zone so as to provide a continuous hot-pressing operation of a plurality of articles.

Reynolds, Jr., Carl D. (Clinton, TN)

1985-01-01

231

Disassembly of hot classical charged drops  

Microsoft Academic Search

The disassembly of hot classical charged drops containing --230 and 130 particles is studied with the molecular dynamics method. The strength of the Coulomb repulsion is chosen so that these drops have a binding energy formula similar to that of nuclei. The phase diagram of neutral matter, obtained by switching off the Coulomb force, is also similar to that of

R. J. Lenk; V. R. Pandharipande

1986-01-01

232

Prototype solar heating and hot water system  

NASA Technical Reports Server (NTRS)

Progress is reported in the development of a solar heating and hot water system which uses a pyramidal optics solar concentrator for heating, and consists of the following subsystems: collector, control, transport, and site data acquisition. Improvements made in the components and subsystems are discussed.

1977-01-01

233

Organizing Hot-Spot Police Patrol Routes  

Microsoft Academic Search

We address the problem of planning patrol routes to maximize coverage of important locations (hot spots) at minimum cost (length of patrol route). We model a road network using an edge-weighted graph in which edges represent streets, vertices represent intersections, and weights represent importance of the corresponding streets. We describe efcient methods that use this input to determine the most

Sudarshan S. Chawathe

2007-01-01

234

Six Hot Topics in Planetary Astronomy  

E-print Network

Six hot topics in modern planetary astronomy are described: 1) lightcurves and densities of small bodies 2) colors of Kuiper belt objects and the distribution of the ultrared matter 3) spectroscopy and the crystallinity of ice in the outer Solar system 4) irregular satellites of the giant planets 5) the Main Belt Comets and 6) comets and meteor stream parents.

David Jewitt

2008-11-14

235

Time to B. cereus about hot chocolate.  

PubMed Central

OBJECTIVE: To determine the cause of illnesses experienced by employees of a Minneapolis manufacturing plant after drinking hot chocolate bought from a vending machine and to explore the prevalence of similar vending machine-related illnesses. METHODS: The authors inspected the vending machines at the manufacturing plant where employees reported illnesses and at other locations in the city where hot chocolate beverages were sold in machines. Tests were performed on dry mix, water, and beverage samples and on machine parts. RESULTS: Laboratory analyses confirmed the presence of B. cereus in dispensed beverages at a concentration capable of causing illness (170,000 count/gm). In citywide testing of vending machines dispensing hot chocolate, 7 of the 39 licensed machines were found to be contaminated, with two contaminated machines having B. cereus levels capable of causing illness. CONCLUSIONS: Hot chocolate sold in vending machines may contain organisms capable of producing toxins that under favorable conditions, can induce illness. Such illnesses are likely to be underreported. Even low concentrations of B. cereus may be dangerous for vulnerable populations such as the aged or immunosuppressed. Periodic testing of vending machines is thus warranted. The relationship between cleaning practices and B. cereus contamination is an issue for further study. PMID:9160059

Nelms, P K; Larson, O; Barnes-Josiah, D

1997-01-01

236

Storage capacity in hot dry rock reservoirs  

DOEpatents

A method is described for extracting thermal energy, in a cyclic manner, from geologic strata which may be termed hot dry rock. A reservoir comprised of hot fractured rock is established and water or other liquid is passed through the reservoir. The water is heated by the hot rock, recovered from the reservoir, cooled by extraction of heat by means of heat exchange apparatus on the surface, and then re-injected into the reservoir to be heated again. Water is added to the reservoir by means of an injection well and recovered from the reservoir by means of a production well. Water is continuously provided to the reservoir and continuously withdrawn from the reservoir at two different flow rates, a base rate and a peak rate. Increasing water flow from the base rate to the peak rate is accomplished by rapidly decreasing backpressure at the outlet of the production well in order to meet periodic needs for amounts of thermal energy greater than a baseload amount, such as to generate additional electric power to meet peak demands. The rate of flow of water provided to the hot dry rock reservoir is maintained at a value effective to prevent depletion of the liquid inventory of the reservoir. 4 figs.

Brown, D.W.

1997-11-11

237

Storage capacity in hot dry rock reservoirs  

DOEpatents

A method of extracting thermal energy, in a cyclic manner, from geologic strata which may be termed hot dry rock. A reservoir comprised of hot fractured rock is established and water or other liquid is passed through the reservoir. The water is heated by the hot rock, recovered from the reservoir, cooled by extraction of heat by means of heat exchange apparatus on the surface, and then re-injected into the reservoir to be heated again. Water is added to the reservoir by means of an injection well and recovered from the reservoir by means of a production well. Water is continuously provided to the reservoir and continuously withdrawn from the reservoir at two different flow rates, a base rate and a peak rate. Increasing water flow from the base rate to the peak rate is accomplished by rapidly decreasing backpressure at the outlet of the production well in order to meet periodic needs for amounts of thermal energy greater than a baseload amount, such as to generate additional electric power to meet peak demands. The rate of flow of water provided to the hot dry rock reservoir is maintained at a value effective to prevent depletion of the liquid

Brown, Donald W. (Los Alamos, NM)

1997-01-01

238

1794 LETTERS TO THE EDITOR HOT RESERVOIR  

E-print Network

1794 LETTERS TO THE EDITOR HEAT REJECTED HEAT HOT RESERVOIR WORK OUTPUT W FIG. 1. Heat engine run from a nonideal thermal source. COLD RESERVOIR Fig. 1, in which the heat engine shown is assumed to be a thermo- electric generator. An electrical analogy of the nonideal heat reservoir is a voltage source e

Abu-Mostafa, Yaser S.

239

Hot-dry-rock geothermal resource 1980  

SciTech Connect

The work performed on hot dry rock (HDR) geothermal resource evaluation, site characterization, and geophysical exploration techniques is summarized. The work was done by region (Far West, Pacific Northwest, Southwest, Rocky Mountain States, Midcontinent, and Eastern) and limited to the conterminous US.

Heiken, G.; Goff, F.; Cremer, G. (ed.)

1982-04-01

240

Solar-powered hot-air system  

NASA Technical Reports Server (NTRS)

Solar-powered air heater supplies part or all of space heating requirements of residential or commercial buildings and is interfaced with air to water heat exchanger to heat domestic hot water. System has potential application in drying agricultural products such as cotton, lumber, corn, grains, and peanuts.

1979-01-01

241

Turbine Engine Hot Section Technology (HOST)  

NASA Technical Reports Server (NTRS)

Research and plans concerning aircraft gas turbine engine hot section durability problems were discussed. Under the topics of structural analysis, fatigue and fracture, surface protective coatings, combustion, turbine heat transfer, and instrumentation specific points addressed were the thermal and fluid environment around liners, blades, and vanes, material coatings, constitutive behavior, stress-strain response, and life prediction methods for the three components.

1982-01-01

242

Lightweight concrete in hot coastal areas  

Microsoft Academic Search

An experimental study was carried out to examine different mixtures made with selected lightweight aggregates for the purpose of producing lightweight concrete. A relatively suitable product is sought in order to provide good quality building materials that can satisfy the conditions of hot coastal environments. Three ways of producing lightweight concrete were used, i.e., lightweight crushed bricks, lightweight expanded clay

Jamal Alduaij; Khalid Alshaleh; M Naseer Haque; Khalid Ellaithy

1999-01-01

243

Hot-embossed polymeric optical waveguides  

Microsoft Academic Search

Polymer waveguides have attracted a great deal of attention for their potential applications as optical components in optical communications, optical interconnections and optical sensors because they are easy to manufacture at a low temperature, and they have a low processing cost. Hot embossing is powerful and effective tools to produce a large volume of waveguides and structure high-precision micro\\/nano patterns

Choon-Gi Choi; Jin-Tae Kim; Sang-Pil Han; Seung-Ho Ahn

2004-01-01

244

Travertine Hot Springs, Mono County, California  

SciTech Connect

This article is an abridgement of Special Report 172, Travertine Hot Springs at Bridgeport, Mono County, California, in preparation at the California Division of Mines and Geology. The Travertine Hot Springs area is on the northern edge of what many consider to be one of the most tectonically active areas in the United States. There is abundant geothermal and seismic activity. The landscape is dotted with volcanic features- cones, craters, domes, flows, fumaroles and hot springs-indicators of unrest in the present as well as reminders of activity in the past. Travertine, also known as calcareous sinter, is limestone formed by chemical precipitation of calcium carbonate (CaCO{sub 3}) from ground or surface waters. It forms stalactites and stalagmites in caves, fills some veins and spring conduits and can also be found at the mouths of springs, especially hot springs. The less compact variety is called tufa and the dense, banded variety is known as Mexican onyx, or onyx marble. True onyx, however, is a banded silicate.

Chesterman, C.W.; Kleinhampl, F.J.

1991-08-01

245

Fly a Hot-Air Balloon  

NSDL National Science Digital Library

Learners assemble a hot-air balloon from tissue paper. The heated air (from a heat gun) inside the balloon is less dense than the surrounding air and causes the balloon to float. Use this activity to introduce learners to density and convection currents. Adult supervision recommended when using the heat gun.

Museum Of Science And Industry, Chicago

2012-01-01

246

Teaching Earth Science Using Hot Air Balloons  

ERIC Educational Resources Information Center

Constructing model hot air balloons is an activity that captures the imaginations of students, enabling teachers to present required content to minds that are open to receive it. Additionally, there are few activities that lend themselves to integrating so much content across subject areas. In this article, the authors describe how they have

Kuhl, James; Shaffer, Karen

2008-01-01

247

CONOCO DOLOMITE HOT GAS CLEANUP SYSTEM  

EPA Science Inventory

This report analyzes a proposal that EPA sponsor a large-scale pilot plant to develop the Conoco (formerly Consol) Dolomite Hot Gas Clean-up system. The report includes a history of the prior development program, the technology involved comparisons with competitive technologies i...

248

World Trade Center Thermal Hot Spots  

USGS Multimedia Gallery

Thermal hotspots around the World Trade Center after the terrorist attacks of September 11, 2001. The images show hot spots and fires still burning in the debris as of September 16, 2001, which were reduced or eliminated by September 23, 2001. These images were produced by the USGS from data gathere...

249

Hot Forming With Electron-Beam Welder  

NASA Technical Reports Server (NTRS)

Hot forming to restore size and shape of thin metal parts done with electron-beam welder. Work-piece heated in scanning defocused electron beam rather than conventional heat-treating furnace. Technique proved successful in straightening some thin flanges of nickel alloy and titanium.

Dobson, R. K.; Whiffen, E. L.

1984-01-01

250

Toads and Red-hot Charcoal  

Microsoft Academic Search

TOADS are associated with some wonderful myths, and my scepticism was naturally great when my friend Mr. H. Martin Leake assured me, while on a visit to Cawnpore in October of 1915, that toads would eat red-hot charcoal. An after-dinner demonstration, however, soon dispelled my doubts. Small fragments of charcoal heated to a glowing red were thrown on the cement

W. N. F. Woodland

1920-01-01

251

Esophageal Thermal Injury by Hot Adlay Tea  

PubMed Central

Reversible thermal injury to the esophagus as the result of drinking hot liquids has been reported to generate alternating white and red linear mucosal bands, somewhat reminiscent of a candy cane. This phenomenon is associated with chest pain, dysphagia, odynophagia, and epigastric pain. Here, we report a case of thermal injury to the esophageal and oral cavity due to the drinking of hot tea, including odynophagia and dysphagia. A 69-year-old man was referred due to a difficulty in swallowing which had begun a week prior to referral. The patient, at the time of admission, was unable to swallow even liquids. He had recently suffered from hiccups, and had consumed five cups of hot adlay tea one week prior to admission, as a folk remedy for the hiccups. Upon physical examination, the patient's oral cavity evidenced mucosal erosion, hyperemia, and mucosa covered by a whitish pseudomembrane. Nonspecific findings were detected on the laboratory and radiological exams. Upper endoscopy revealed diffuse hyperemia, and erosions with thick and whitish pseudomembraneous mucosa on the entire esophagus. The stomach and duodenum appeared normal. We diagnosed the patient with thermal esophageal injury inflicted by the hot tea. He was treated with pantoprazole, 40 mg/day, for 14 days, and evidenced significant clinical and endoscopic improvement. PMID:17427650

Go, Hoon; Jung, Sung Hee; Park, Young A; Lee, Jung Yun; Kim, Sae Hee; Lim, Sin Hyung

2007-01-01

252

Thursday 21 October 1999 physics : Bubbling hot  

E-print Network

the squeeze when the tension is succeeded by a wave of compression, and their contents heat up dramatically. Theory predicts that temperatures in bubbles generated by this process, known as 'acoustic cavitation, acoustic cavitation presents a few experimental challenges: good measurements inside a hot, cavitating

Suslick, Kenneth S.

253

A study of the hot working behavior of Al-Mg alloy 5052 by hot torsion testing  

NASA Astrophysics Data System (ADS)

The hot working behavior of commercial Al-2.5 wt pct Mg alloy 5052 was studied using hot torsion testing to simulate commercial hot rolling. The effects of homogenization time and temperature, and deformation temperature on the flow stress and hot ductility were carefully assessed. Microstructural characterizations and differential thermal analyses were performed to help explain the torsion data obtained. Significant variations in hot working behavior were noted for material machined from different regions of the commercial ingot studied. The constituent particles were found to play a significant role in determining the hot ductility of the alloy.

Precht, W.; Pickens, J. R.

1987-09-01

254

Hot and cold cognition in depression.  

PubMed

We discuss the importance of cognitive abnormalities in unipolar depression, drawing the distinction between "hot" (emotion-laden) and "cold" (emotion-independent) cognition. "Cold" cognitive impairments are present reliably in unipolar depression, underscored by their presence in the diagnostic criteria for major depressive episodes. There is good evidence that some "cold" cognitive abnormalities do not disappear completely upon remission, and that they predict poor response to antidepressant drug treatment. However, in many studies the degree of impairment is moderately related to symptoms. We suggest that "cold" cognitive deficits in unipolar depression may in part be explicable in terms of alterations in "hot" processing, particularly on tasks that utilize feedback, on which depressed patients have been reported to exhibit a "catastrophic response to perceived failure." Other abnormalities in "hot" cognition are commonly observed on tasks utilizing emotionally valenced stimuli, with numerous studies reporting mood-congruent processing biases in depression across a range of cognitive domains. Additionally, an emerging literature indicates reliable reward and punishment processing abnormalities in depression, which are especially relevant for hard-to-treat symptoms such as anhedonia. Both emotional and reward biases are strongly influenced by manipulations of the neurochemical systems targeted by antidepressant drugs. Such a pattern of "hot" and "cold" cognitive abnormalities is consistent with our cognitive neuropsychological model of depression, which proposes central roles for cognitive abnormalities in the generation, maintenance, and treatment of depressive symptoms. Future work should examine in greater detail the role that "hot" and "cold" cognitive processes play in mediating symptomatic improvement following pharmacological, psychological, and novel brain circuit-level interventions. PMID:23481353

Roiser, Jonathan P; Sahakian, Barbara J

2013-06-01

255

WESF hot cells waste minimization criteria hot cells window seals evaluation  

SciTech Connect

WESF will decouple from B Plant in the near future. WESF is attempting to minimize the contaminated solid waste in their hot cells and utilize B Plant to receive the waste before decoupling. WESF wishes to determine the minimum amount of contaminated waste that must be removed in order to allow minimum maintenance of the hot cells when they are placed in ''laid-up'' configuration. The remaining waste should not cause unacceptable window seal deterioration for the remaining life of the hot cells. This report investigates and analyzes the seal conditions and hot cell history and concludes that WESF should remove existing point sources, replace cerium window seals in F-Cell and refurbish all leaded windows (except for A-Cell). Work should be accomplished as soon as possible and at least within the next three years.

Walterskirchen, K.M.

1997-03-31

256

DETAIL OF THERMALWATER FLOW METER. Hot Springs National Park, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DETAIL OF THERMAL-WATER FLOW METER. - Hot Springs National Park, Bathhouse Row, Superior Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

257

THERMALWATER FLOW METER. Hot Springs National Park, Bathhouse Row, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

THERMAL-WATER FLOW METER. - Hot Springs National Park, Bathhouse Row, Superior Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

258

5. FLOW METER AND PIPING SHOWING CONNECTIONS. Hot Springs ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. FLOW METER AND PIPING SHOWING CONNECTIONS. - Hot Springs National Park Bathhouse Row, Maurice Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

259

6. UNIT VENTILATOR, WOMEN'S COOLING ROOM. Hot Springs National ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. UNIT VENTILATOR, WOMEN'S COOLING ROOM. - Hot Springs National Park, Bathhouse Row, Ozark Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

260

7. UNIT VENTILATOR, DETAIL OF MOTOR AND FANS. Hot ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. UNIT VENTILATOR, DETAIL OF MOTOR AND FANS. - Hot Springs National Park, Bathhouse Row, Ozark Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

261

1. View of rmad from jr. hot cell, facing north ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. View of r-mad from jr. hot cell, facing north - Nevada Test Site, Reactor Maintenance & Disassembly Complex, Junior Hot Cell, Jackass Flats, Area 25, South of intersection of Roads F & G, Mercury, Nye County, NV

262

9. VAPOR STALL IN MEN'S BATH HALL. Hot Springs ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. VAPOR STALL IN MEN'S BATH HALL. - Hot Springs National Park, Bathhouse Row, Buckstaff Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 Mile North of U.S. Highway 70, Hot Springs, Garland County, AR

263

5. HORIZONTAL COOLEDWATER STORAGE TANKS. Hot Springs National Park, ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. HORIZONTAL COOLED-WATER STORAGE TANKS. - Hot Springs National Park, Bathhouse Row, Fordyce Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

264

13. Underside Span 1, Hot Metal Bridge on right toward ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. Underside Span 1, Hot Metal Bridge on right toward Pier 1. - Monongahela Connecting Railroad Company, Hot Metal Bridge, Spanning Monongahela River at mile post 3.1, Pittsburgh, Allegheny County, PA

265

1. TEMPERING COILS IN WIND TUNNEL. Hot Springs National ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. TEMPERING COILS IN WIND TUNNEL. - Hot Springs National Park, Bathhouse Row, Buckstaff Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 Mile North of U.S. Highway 70, Hot Springs, Garland County, AR

266

1. PLENUM INTERIOR, SHOWING HEATING COILS AND BYPASS Hot ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. PLENUM INTERIOR, SHOWING HEATING COILS AND BY-PASS - Hot Springs National Park, Bathhouse Row, Fordyce Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

267

The High Albedo of the Hot Jupiter Kepler-7 B  

E-print Network

Hot Jupiters are expected to be dark from both observations (albedo upper limits) and theory (alkali metals and/or TiO and VO absorption). However, only a handful of hot Jupiters have been observed with high enough photometric ...

Demory, Brice-Olivier

268

ConcepTest: Hot/Cold Water Circulation  

NSDL National Science Digital Library

A fish tank is filled almost to the brim with room temperature water. Two containers of cold and hot water are prepared. Red coloring is added to the hot water, blue coloring is added to the cold water. The cold ...

269

Orlando 2006: plastic surgeons rate the "Hot Topics".  

PubMed

During the "Hot Topics" seminar at The Aesthetic Meeting 2006, authors polled participants to gain insight into how plastic surgeons evaluate current hot topics. Here are the results as well as the authors' notes on additional presentations. PMID:19338937

Gryskiewicz, Joe M; Adams, William P

2006-01-01

270

2. ELEVATOR DRIVE, CABLE MOTOR, CIRCUIT BOX, Hot Springs ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. ELEVATOR DRIVE, CABLE MOTOR, CIRCUIT BOX, - Hot Springs National Park, Bathhouse Row, Fordyce Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

271

7 CFR 305.22 - Hot water immersion treatment schedules.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Hot water immersion treatment schedules. 305...Continued) ANIMAL AND PLANT HEALTH INSPECTION...AGRICULTURE PHYTOSANITARY TREATMENTS Heat Treatments 305.22 Hot water immersion treatment schedules....

2010-01-01

272

Measurement of turbulent fluctuations in high-speed flows using hot wires and hot films  

NASA Technical Reports Server (NTRS)

The paper examines the dynamic calibrations of the hot film and modified hot-wire probes with a view to assess their suitability for use in experiments for the measurement of turbulent fluctuations in compressible boundary-layer flows. Results are presented of tests on some sensors in both subsonic and supersonic boundary-layer flows. A simple technique is presented for determining dynamic calibration correction factors for the sensitivities involved.

Acharya, M.

1979-01-01

273

HOT CELL BUILDING, TRA632, INTERIOR. CONTEXTUAL VIEW OF HOT CELL ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HOT CELL BUILDING, TRA-632, INTERIOR. CONTEXTUAL VIEW OF HOT CELL NO. 2 FROM STAIRWAY ALONG NORTH WALL. OBSERVATION WINDOW ALONG WEST SIDE BENEATH "CELL 2" SIGN. DOORWAY IN LEFT OF VIEW LEADS TO CELL 1 WORK AREA OR TO EXIT OUTDOORS TO NORTH. RADIATION DETECTION MONITOR TO RIGHT OF DOOR. CAMERA FACING SOUTHWEST. INL NEGATIVE NO. HD46-28-3. Mike Crane, Photographer, 2/2005 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

274

Toward the Detection of Transiting Hot Earths and Hot Neptunes in Open Clusters  

E-print Network

Radial velocity searches for extrasolar planets have recently detected several very low mass (7-20M_Earth) planets in close orbits with periods planets in Galactic open clusters via transits. We outline the requirements for constructing a transit survey that would allow one to probe such ``Hot Earths'' and ``Hot Neptunes.'' Specifically, we present a simple criterion for detection that defines the minimum aperture required to detect planets of a given radius in a cluster at a given distance. Adopting photometric precisions that have been demonstrated in state-of-the-art variability surveys, we then predict the number of planets one could potentially detect with ambitious transit surveys toward several open clusters. Dedicated surveys lasting more than 20 nights with Pan-STARRS toward the Hyades and Praesepe could detect a handful of Hot Earths, if the majority of stars host such planets. Similar surveys with larger aperture telescopes (e.g. CFHT, MMT), toward M67, M35, M50, and M37 could detect Hot Neptunes, provided that their frequency is >1%. The majority of planets will be detected around M dwarfs; detecting Hot Neptunes around such primaries requires photometric precisions of ~1%, whereas Hot Earths require \\~0.1%. We discuss potential hurdles in detecting and confirming small planets in ground-based surveys, including correlated noise, false positives, and intrinsic stellar variability.

Joshua Pepper; B. Scott Gaudi

2005-07-22

275

Oxidation and hot corrosion of hot-pressed Si3N4 at 1000 deg C  

NASA Technical Reports Server (NTRS)

The oxidation and hot corrosion of a commercial, hot-pressed Si3N4 were investigated at 1000 C under an atmosphere of flowing O2. For the hot corrosion studies, thin films of Na2SO4 were airbrushed on the Si3N4 surface. The hot corrosion attack was monitored by the following techniques: continuous weight measurements, SO2 evolution, film morphology, and chemical analyses. Even though the hot corrosion weight changes after 25 hr were relatively small, the formation of SiO2 from oxidation of Si3N4 was an order of magnitude greater in the presence of molten Na2SO4. The formation of a protective SiO2 phase at the Si3N4 surface is minimized by the fluxing action of the molten Na2SO4 thereby allowing the oxidation of the Si3N4 to proceed more rapidly. A simple process is proposed to account for the hot corrosion process.

Fielder, W. L.

1985-01-01

276

Hot-Film and Hot-Wire Anemometry for a Boundary Layer Active Flow Control Test  

NASA Technical Reports Server (NTRS)

Unsteady active flow control (AFC) has been used experimentally for many years to minimize bluff-body drag. This technology could significantly improve performance of rotorcraft by cleaning up flow separation. It is important, then, that new actuator technologies be studied for application to future vehicles. A boundary layer wind tunnel was constructed with a 1ft-x-3ft test section and unsteady measurement instrumentation to study how AFC manipulates the boundary layer to overcome adverse pressure gradients and flow separation. This unsteady flow control research requires unsteady measurement methods. In order to measure the boundary layer characteristics, both hot-wire and hot-film Constant Temperature Anemometry is used. A hot-wire probe is mounted in the flow to measure velocity while a hot-film array lays on the test surface to measure skin friction. Hot-film sensors are connected to an anemometer, a Wheatstone bridge circuit with an output that corresponds to the dynamic flow response. From this output, the time varying flow field, turbulence, and flow reversal can be characterized. Tuning the anemometers requires a fan test on the hot-film sensors to adjust each output. This is a delicate process as several variables drastically affect the data, including control resistance, signal input, trim, and gain settings.

Lenahan, Keven C.; Schatzman, David M.; Wilson, Jacob Samuel

2013-01-01

277

Hot Springs Metropolitan Planning Organization 2030 Long Range Transportation Plan  

E-print Network

Spring County City of Hot Springs City of Mountain Pine Hot Springs Village The Greater Hot Springs Chamber of Commerce The Arkansas State Highway and Transportation Department In Cooperation With United States Department of Transportation... Federal Highway Administration Federal Transit Administration 2030 Long Range Transportation Plan for the Hot Springs Area Metropolitan Planning Organization This LRTP has been funded with federal Metropolitan Planning (PL) funds through...

Hot Springs Metropolitan Planning Organization

2005-11-03

278

The Hot Stars in Symbiotic Systems  

NASA Astrophysics Data System (ADS)

Symbiotic stars are interacting binaries, consisting of a late giant and a very hot companion, whose radiation ionizes the wind from the cool star. They strike the observers by their complex spectra and variability. A small subgroup, the symbiotic novae, undergo outbursts with an amplitude of several magnitudes and a duration of several decades. The ionizing binary component is usually too hot to be observed in the optical light. It emits mainly EUV photons, and in spectral regions better accessible to observers, nebula and cool star are much brighter than the hot star. Direct observations of hot components have therefore been restricted to special cases. Consequently, our knowledge about the hot components was poor. This thesis presents indirect methods allowing to extract crucial information on the ionizing star from the spectrum of the ionized nebula. Fundamental characteristics such as temperature, radius, and outburst energy are determined. They characterize the nature of the hot star, its outbursts, and the evolutionary status of the system. The IUE archive proved best suited as observational base. It contains thousands of far UV spectra of symbiotic stars. The UV continuum and the He II lambda-1640 recombination line turned out to be particularly sensitive to the hot star's parameters. For one object ROSAT observations of photospheric X-ray emission exist. They confirm the results obtained from IUE spectra. Unfortunately, only a subset of the symbiotics are bright enough to be observable in the UV, and moreover, the outburst of most symbiotic novae started long before the advent of space observatories. Possibilities to use optical spectroscopy are explored for these cases. T* can be derived from the observed ionization stages, and L* can be estimated from UBV magnitudes. The main result is displayed in Figure 1. Typically, the hot component of a symbiotic system has a radius ~0.1~R\\odot, a surface temperature ~100,000~K, and a luminosity ~1000~L\\odot. They occupy the same portion of the HR diagram as nova remnants and central stars of planetary nebulae. Like these, they seem to be basically white dwarfs with a hot atmosphere. They have not yet cooled or have been re-heated due to accretion of matter from the red giant. In particular, the results for the outbursts of symbiotic novae confirm the commonly adopted scenario of a thermo-nuclear event in an accreted layer on the surface of a white dwarf, largely analogous to a classical nova outburst. Unlike in classical novae, the cool component remains outside the outburst event, and the accreted matter slowly burns out over decades. While classical novae are hard to investigate when fading, the evolution of symbiotic novae can be tracked with the help of the subsisting nebular emission from the ionized part of the red giant's wind. The evolutionary paths roughly follow the theoretical models for novae. During the outburst of a symbiotic nova an energy around ~10^47~erg is released, i.e. ~10^-5 M\\odot of hydrogen is burnt. Besides supernovae, the outburst of symbiotic novae are the most energetic stellar events. The thesis is written in German. (SECTION: Dissertation Summaries)

Muerset, Urs

1995-01-01

279

Hot cold optimization of large Windows\\/NT applications  

Microsoft Academic Search

A dynamic instruction trace often contains many unnecessary instructions that are required only by the unexecuted portion of the program. Hot-cold optimization (HCO) is a technique that realizes this performance opportunity. HCO uses profile information to partition each routine into frequently executed (hot) and infrequently executed (cold) parts. Unnecessary operations in the hot portion are removed, and compensation code is

Robert S. Cohn; P. Geoffrey Lowney

1996-01-01

280

STATE OF CALIFORNIA SOLAR DOMESTIC HOT WATER SYSTEMS (SDHW)  

E-print Network

STATE OF CALIFORNIA SOLAR DOMESTIC HOT WATER SYSTEMS (SDHW) CEC- CF-6R-MECH-02 (Revised 08/09) CALIFORNIA ENERGY COMMISSION INSTALLATION CERTIFICATE CF-6R-MECH-02 Solar Domestic Hot Water Systems (SDHW 2009 SOLAR HOT WATER HEATING SYSTEMS: SRCC Certified Mfr Name & Model Number Net Solar Fraction (from

281

Installation package for a solar heating and hot water system  

NASA Technical Reports Server (NTRS)

Development and installation of two commercial solar heating and hot water systems are reported. The systems consist of the following subsystems: collector, storage, transport, hot water, auxiliary energy and controls. General guidelines are provided which may be utilized in development of detailed installation plans and specifications. In addition, operation, maintenance and repair of a solar heating and hot water system instructions are included.

1978-01-01

282

HATCH CONNECTING TEMPERED AIR CHAMBER AND HOT AIR CHAMBER OF ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HATCH CONNECTING TEMPERED AIR CHAMBER AND HOT AIR CHAMBER OF PLENUM WITH ATTACHED DRAFT REGULATOR. - Hot Springs National Park, Bathhouse Row, Superior Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

283

10 CFR 431.102 - Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water...  

Code of Federal Regulations, 2014 CFR

... Energy 3 2014-01-01 2014-01-01 false Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water storage tanks. 431.102 Section 431.102 Energy DEPARTMENT OF ENERGY ENERGY...

2014-01-01

284

10 CFR 431.102 - Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water...  

Code of Federal Regulations, 2011 CFR

... Energy 3 2011-01-01 2011-01-01 false Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water storage tanks. 431.102 Section 431.102 Energy DEPARTMENT OF ENERGY ENERGY...

2011-01-01

285

10 CFR 431.102 - Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water...  

Code of Federal Regulations, 2012 CFR

... Energy 3 2012-01-01 2012-01-01 false Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water storage tanks. 431.102 Section 431.102 Energy DEPARTMENT OF ENERGY ENERGY...

2012-01-01

286

10 CFR 431.102 - Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water...  

Code of Federal Regulations, 2013 CFR

... Energy 3 2013-01-01 2013-01-01 false Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water storage tanks. 431.102 Section 431.102 Energy DEPARTMENT OF ENERGY ENERGY...

2013-01-01

287

10 CFR 431.102 - Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water...  

Code of Federal Regulations, 2010 CFR

... Energy 3 2010-01-01 2010-01-01 false Definitions concerning commercial water heaters, hot water supply boilers, and unfired hot water storage tanks. 431.102 Section 431.102 Energy DEPARTMENT OF ENERGY ENERGY...

2010-01-01

288

Hot Electron Injection into Uniaxially Strained Silicon  

NASA Astrophysics Data System (ADS)

In semiconductor spintronics, silicon attracts great attention due to the long electron spin lifetime. Silicon is also one of the most commonly used semiconductor in microelectronics industry. The spin relaxation process of diamond crystal structure such as silicon is dominant by Elliot-Yafet mechanism. Yafet shows that intravalley scattering process is dominant. The conduction electron spin lifetime measured by electron spin resonance measurement and electronic measurement using ballistic hot electron method well agrees with Yafet's theory. However, the recent theory predicts a strong contribution of intervalley scattering process such as f-process in silicon. The conduction band minimum is close the Brillouin zone edge, X point which causes strong spin mixing at the conduction band. A recent experiment of electric field-induced hot electron spin relaxation also shows the strong effect of f-process in silicon. In uniaxially strained silicon along crystal axis [100], the suppression of f-process is predicted which leads to enhance electron spin lifetime. By inducing a change in crystal structure due to uniaxial strain, the six fold degeneracy becomes two fold degeneracy, which is valley splitting. As the valley splitting increases, intervalley scattering is reduced. A recent theory predicts 4 times longer electron spin lifetime in 0.5% uniaxially strained silicon. In this thesis, we demonstrate ballistic hot electron injection into silicon under various uniaxial strain. Spin polarized hot electron injection under strain is experimentally one of the most challenging part to measure conduction electron spin lifetime in silicon. Hot electron injection adopts tunnel junction which is a thin oxide layer between two conducting materials. Tunnel barrier, which is an oxide layer, is only 4 5 nm thick. Also, two conducting materials are only tens of nanometer. Therefore, under high pressure to apply 0.5% strain on silicon, thin films on silicon substrate can be easily destroyed. In order to confirm the performance of tunnel junction, we use tunnel magnetoresistance(TMR). TMR consists of two kinds of ferromagnetic materials and an oxide layer as tunnel barrier in order to measure spin valve effect. Using silicon as a collector with Schottky barrier interface between metal and silicon, ballistic hot spin polarized electron injection into silicon is demonstrated. We also observed change of coercive field and magnetoresistance due to modification of local states in ferromagnetic materials and surface states at the interface between metal and silicon due to strain.

Kim, Hyun Soo

289

Advances in Hot-Structure Development  

NASA Technical Reports Server (NTRS)

The National Aeronautics and Space Administration has actively participated in the development of hot structures technology for application to hypersonic flight systems. Hot structures have been developed for vehicles including the X-43A, X-37, and the Space Shuttle. These trans-atmospheric and atmospheric entry flight systems that incorporate hot-structures technology are lighter weight and require less maintenance than those that incorporate parasitic, thermal-protection materials that attach to warm or cool substructure. The development of hot structures requires a thorough understanding of material performance in an extreme environment, boundary conditions and load interactions, structural joint performance, and thermal and mechanical performance of integrated structural systems that operate at temperatures ranging from 1500 C to 3000 C, depending on the application. This paper will present recent advances in the development of hot structures, including development of environmentally durable, high temperature leading edges and control surfaces, integrated thermal protection systems, and repair technologies. The X-43A Mach-10 vehicle utilized carbon/carbon (C/C) leading edges on the nose, horizontal control surface, and vertical tail. The nose and vertical and horizontal tail leading edges were fabricated out of a 3:1 biased, high thermal conductivity C/C. The leading edges were coated with a three-layer coating comprised of a SiC conversion of the C/C, followed by a CVD layer of SiC, followed by a thin CVD layer of HfC. Work has also been performed on the development of an integrated structure and was focused on both hot and warm (insulated) structures and integrated fuselage/tank/TPS systems. The objective was to develop integrated multifunctional airframe structures that eliminate fragile external thermal-protection systems and incorporate the insulating function within the structure. The approach taken to achieve this goal was to develop candidate hypersonic airframe concepts, including structural arrangement, load paths, thermal-structural wall design, thermal accommodation features, and integration of major components, optimize thermalstructural configurations, and validate concepts through a building block test program and generate data to improve and validate analytical and design tools.

Rivers, H. Kevin; Glass, David E.

2006-01-01

290

Baroclinic Instability on Hot Extrasolar Planets  

E-print Network

We investigate baroclinic instability in flow conditions relevant to hot extrasolar planets. The instability is important for transporting and mixing heat, as well as for influencing large-scale variability on the planets. Both linear normal mode analysis and non-linear initial value calculations are carried out -- focusing on the freely-evolving, adiabatic situation. Using a high-resolution general circulation model (GCM) which solves the traditional primitive equations, we show that large-scale jets similar to those observed in current GCM simulations of hot extrasolar giant planets are likely to be baroclinically unstable on a timescale of few to few tens of planetary rotations, generating cyclones and anticyclones that drive weather systems. The growth rate and scale of the most unstable mode obtained in the linear analysis are in qualitative, good agreement with the full non-linear calculations. In general, unstable jets evolve differently depending on their signs (eastward or westward), due to the chang...

Polichtchouk, Inna

2012-01-01

291

Visual Companions to Transiting Hot Jupiters  

NASA Astrophysics Data System (ADS)

The known short period giant planets constitute a valuable statistical population. From the derived physical and orbital properties of this sample in conjunction with detailed studies of individual objects, we can investigate a wide array of topics, including the internal structures of giant planets, the conditions under which planets form, and their dynamical evolution. The success of such studies relies, of course, on the completeness and accuracy of the underlying data, but many of the known hot Jupiters have not been subjected to high resolution imaging in search of close stellar companions. The presence of a second star (whether physically bound or a chance alignment), can affect the derived stellar and planetary parameters. Moreover, the presence of bound companions can inform us about planetary formation and migration in binary systems. Here we present preliminary results from our adaptive optics survey of 94 transiting hot Jupiter host stars and discuss their significance in the context outlined above.

Quinn, Samuel Noah; Buchhave, Lars A.; White, Russel J.; Raghavan, Deepak

2014-06-01

292

The decay of hot KK space  

E-print Network

The non-perturbative instabilities of hot Kaluza-Klein spacetime are investigated. In addition to the known instability of hot space (the nucleation of 4D black holes) and the known instability of KK space (the nucleation of bubbles of nothing by quantum tunneling), we find two new instabilities: the nucleation of 5D black holes, and the nucleation of bubbles of nothing by thermal fluctuation. These four instabilities are controlled by two Euclidean instantons, with each instanton doing double duty via two inequivalent analytic continuations; thermodynamic instabilities of one are shown to be related to mechanical instabilities of the other. I also construct bubbles of nothing that are formed by a hybrid process involving both thermal fluctuation and quantum tunneling. There is an exact high-temperature/low-temperature duality that relates the nucleation of black holes to the nucleation of bubbles of nothing.

Adam R. Brown

2014-08-25

293

Enabling Technologies for Ceramic Hot Section Components  

SciTech Connect

Silicon-based ceramics are attractive materials for use in gas turbine engine hot sections due to their high temperature mechanical and physical properties as well as lower density than metals. The advantages of utilizing ceramic hot section components include weight reduction, and improved efficiency as well as enhanced power output and lower emissions as a result of reducing or eliminating cooling. Potential gas turbine ceramic components for industrial, commercial and/or military high temperature turbine applications include combustor liners, vanes, rotors, and shrouds. These components require materials that can withstand high temperatures and pressures for long duration under steam-rich environments. For Navy applications, ceramic hot section components have the potential to increase the operation range. The amount of weight reduced by utilizing a lighter gas turbine can be used to increase fuel storage capacity while a more efficient gas turbine consumes less fuel. Both improvements enable a longer operation range for Navy ships and aircraft. Ceramic hot section components will also be beneficial to the Navy's Growth Joint Strike Fighter (JSF) and VAATE (Versatile Affordable Advanced Turbine Engines) initiatives in terms of reduced weight, cooling air savings, and capability/cost index (CCI). For DOE applications, ceramic hot section components provide an avenue to achieve low emissions while improving efficiency. Combustors made of ceramic material can withstand higher wall temperatures and require less cooling air. Ability of the ceramics to withstand high temperatures enables novel combustor designs that have reduced NO{sub x}, smoke and CO levels. In the turbine section, ceramic vanes and blades do not require sophisticated cooling schemes currently used for metal components. The saved cooling air could be used to further improve efficiency and power output. The objectives of this contract were to develop technologies critical for ceramic hot section components for gas turbine engines. Significant technical progress has been made towards maturation of the EBC and CMC technologies for incorporation into gas turbine engine hot-section. Promising EBC candidates for longer life and/or higher temperature applications relative to current state of the art BSAS-based EBCs have been identified. These next generation coating systems have been scaled-up from coupons to components and are currently being field tested in Solar Centaur 50S engine. CMC combustor liners were designed, fabricated and tested in a FT8 sector rig to demonstrate the benefits of a high temperature material system. Pretest predictions made through the use of perfectly stirred reactor models showed a 2-3x benefit in CO emissions for CMC versus metallic liners. The sector-rig test validated the pretest predictions with >2x benefit in CO at the same NOx levels at various load conditions. The CMC liners also survived several trip shut downs thereby validating the CMC design methodology. Significant technical progress has been made towards incorporation of ceramic matrix composites (CMC) and environmental barrier coatings (EBC) technologies into gas turbine engine hot-section. The second phase of the program focused on the demonstration of a reverse flow annular CMC combustor. This has included overcoming the challenges of design and fabrication of CMCs into 'complex' shapes; developing processing to apply EBCs to 'engine hardware'; testing of an advanced combustor enabled by CMCs in a PW206 rig; and the validation of performance benefits against a metal baseline. The rig test validated many of the pretest predictions with a 40-50% reduction in pattern factor compared to the baseline and reductions in NOx levels at maximum power conditions. The next steps are to develop an understanding of the life limiting mechanisms in EBC and CMC materials, developing a design system for EBC coated CMCs and durability testing in an engine environment.

Venkat Vedula; Tania Bhatia

2009-04-30

294

Hot-water power from the earth  

SciTech Connect

This article examines geothermal sites on the West Coast in order to show the progress that has been made in converting geothermal energy into usable electric power. Only about 0.5% of the earth's geothermal reserve can be brought to the surface as dry steam. California's Imperial Valley is possibly the largest geothermal resource in the US. Three demonstration generating plants are each producing between 10 and 14 MW of power near the valley's Salton Sea. The high-temperature water (above 410/sup 0/F) at Brawley is drawn from wells tapping the subterranean reservoir. It is proposed that hot-water power will be economical when methods are found to extract maximum energy from a geothermal deposit and to control clogging and corrosion caused by minerals dissolved in the hot fluid.

Not Available

1984-02-01

295

Method for hot pressing beryllium oxide articles  

DOEpatents

The hot pressing of beryllium oxide powder into high density compacts with little or no density gradients is achieved by employing a homogeneous blend of beryllium oxide powder with a lithium oxide sintering agent. The lithium oxide sintering agent is uniformly dispersed throughout the beryllium oxide powder by mixing lithium hydroxide in an aqueous solution with beryllium oxide powder. The lithium hydroxide is converted in situ to lithium carbonate by contacting or flooding the beryllium oxide-lithium hydroxide blend with a stream of carbon dioxide. The lithium carbonate is converted to lithium oxide while remaining fixed to the beryllium oxide particles during the hot pressing step to assure uniform density throughout the compact.

Ballard, Ambrose H. (Oak Ridge, TN); Godfrey, Jr., Thomas G. (Oak Ridge, TN); Mowery, Erb H. (Clinton, TN)

1988-01-01

296

Hierarchical Simulation of Hot Composite Structures  

NASA Technical Reports Server (NTRS)

Computational procedures are described to simulate the thermal and mechanical behavior of high temperature metal matrix composites (HT-MMC) in the following three broad areas: (1) Behavior of HT-MMC's from micromechanics to laminate via Metal Matrix Composite Analyzer (METCAN), (2) tailoring of HT-MMC behavior for optimum specific performance via Metal Matrix Laminate Tailoring (MMLT), and (3) HT-MMC structural response for hot structural components via High Temperature Composite Analyzer (HITCAN). Representative results from each area are presented to illustrate the effectiveness of computational simulation procedures. The sample case results show that METCAN can be used to simulate material behavior such as strength, stress-strain response, and cyclic life in HTMMC's; MMLT can be used to tailor the fabrication process for optimum performance such as that for in-service load carrying capacity of HT-MMC's; and HITCAN can be used to evaluate static fracture and fatigue life of hot pressurized metal matrix composite rings.

Chamis, C. C.; Murthy, P. L. N.; Singhal, S. N.

1993-01-01

297

Legionella Infection Risk from Domestic Hot Water  

Microsoft Academic Search

We investigated Legionella and Pseudomonas con- tamination of hot water in a cross-sectional multicentric sur- vey in Italy. Chemical parameters (hardness, free chlorine, and trace elements) were determined. Legionella spp. were detected in 33 (22.6%) and Pseudomonas spp. in 56 (38.4%) of 146 samples. Some factors associated with Legionella contamination were heater type, tank distance and capacity, water plant age,

Paola Borella; M. Teresa Montagna; Vincenzo Romano-Spica; Serena Stampi; Giovanna Stancanelli; Maria Triassi; Rachele Neglia; Isabella Marchesi; Guglielmina Fantuzzi; Daniela Tat; Christian Napoli; Gianluigi Quaranta; Patrizia Laurenti; Erica Leoni; Giovanna De Luca; Cristina Ossi; Matteo Moro; Gabriella Ribera D'Alcal

2004-01-01

298

Virus Silicification under Simulated Hot Spring Conditions  

NASA Astrophysics Data System (ADS)

Silicification of organisms in silica-depositing environments can impact both their ecology and their presence in the fossil record. Although microbes have been silicified under laboratory and environmental conditions, viruses have not. Bacteriophage T4 was successfully silicified under laboratory conditions that closely simulated those found in silica-depositing hot springs. Virus morphology was maintained, and a clear elemental signature of phosphorus was detected by energy-dispersive X-ray spectrophotometry (EDS).

Laidler, James R.; Stedman, Kenneth M.

2010-07-01

299

Reduced metal consumption in hot pipe rolling  

Microsoft Academic Search

Means of reducing the metal consumption in the hot rolling of seamless pipe are considered. The most common is the use of\\u000a square or round continuous-cast billet. The trimming required for Pilger mills may be reduced by preparation of the front\\u000a ends of the sleeves in skew rolling and rolling of the rear end at the free section of the

Yu. S. Krivchenko; V. F. Balakin; Yu. D. Ugryumov; G. N. Kushchinskii; V. V. Perchanik; D. Yu. Ugryumov

2010-01-01

300

Hot One-Temperature Accretion Flows Revisited  

E-print Network

The effectiveness of the thermal coupling of ions and electrons in the context of optically thin, hot accretion flows is investigated. In the limit of complete coupling, we focus on the one-temperature accretion flows. Based on a global analysis, the results are compared with two-temperature accretion flow models and with the observations of black hole sources. Many features are quite similar. That is, hot one-temperature solutions are found to exist for mass flow rates less than a critical value; i.e., $\\dot{M}\\la 10\\alpha^2\\dot{M}_{\\rm Edd}$, where $\\dot{M}_{\\rm Edd}= L_{\\rm Edd}/c^2$ is the Eddington accretion rate. At low mass flow rates, $\\dot{M}\\la 10^{-3}\\alpha^2 \\dot{M}_{\\rm Edd}$, the solution is in the advection-dominated accretion flow (ADAF) regime. But at higher rates, radiative cooling is effective and is mainly balanced by advective {\\em heating}, placing the solution in the regime of luminous hot accretion flow (LHAF). To test the viability of the one-temperature models, we have fitted the spectra of the two black hole sources, Sgr A* and XTE J1118+480, which have been examined successfully with two-temperature models. It is found that the one-temperature models do not provide acceptable fits to the multi-wavelength spectra of Sgr A* nor to XTE J1118+480 as a result of the higher temperatures characteristic of the one-temperature models. It is concluded that the thermal coupling of ions and electrons cannot be fully effective and that a two-temperature description is required in hot accretion flow solutions.

Feng Yuan; Ronald E. Taam; Yongquan Xue; Wei Cui

2005-09-11

301

Drowning and the Influence of Hot Weather  

PubMed Central

Background Drowning deaths are devastating and preventable. Public perception does not regard hot weather as a common scenario for drowning deaths. The objective of our study was to test the association between hot weather and drowning risk. Materials and Methods We conducted a retrospective case-crossover analysis of all unintentional drowning deaths in Ontario, Canada from 1999 to 2009. Demographic data were obtained from the Office of the Chief Coroner. Weather data were obtained from Environment Canada. We used the pair-matched analytic approach for the case-crossover design to contrast the weather on the date of the drowning with the weather at the same location one week prior (control period). Results We identified 1243 drowning deaths. The mean age was 40 years, 82% were male, and most events (71%) occurred in open water. The pair-matched analytic approach indicated that temperatures exceeding 30C were associated with a 69% increase in the risk of outdoor drowning (OR?=?1.69, 95% CI 1.232.25, p?=?0.001). For indoor drowning, however, temperatures exceeding 30C were not associated with a statistically significant increase in the risk of drowning (OR?=?1.50, 95% CI 0.534.21, p?=?0.442). Adult men were specifically prone to drown in hot weather (OR 1.67, 95% CI 1.192.34, p?=?0.003) yet an apparent increase in risk extended to both genders and all age groups. Conclusion Contrary to popular belief, hot weather rather than cold stormy weather increases the risk of drowning. An awareness of this risk might encourage greater use of drowning prevention strategies known to save lives. PMID:23977112

Fralick, Michael; Denny, Christopher J.; Redelmeier, Donald A.

2013-01-01

302

Residential conservation demonstration program: domestic hot water  

SciTech Connect

Four types of domestic hot water (DHW) systems installed in 80 homes throughout Florida are currently monitored by the Florida Solar Energy Center (FSEC) under a demonstration program for the Florida Public Service Commission. DHW systems selected for the program are located in four major population areas of Florida: Jacksonville, Orlando/Brevard County, North Palm Beach/Ft. Lauderdale, and the Tampa Bay region. Twenty systems of each DHW type - conventional electric water heaters, heat pump water heaters, solar hot water systems, and waste heat recovery units - are metered to determine electricity use and hot water energy production. A microcomputer-based data acquisition system collects 15-minute interval data at each site and returns it to FSEC over the telephone network semi-weekly. The data is analyzed to determine the average system efficiency and the time-of-day water and electricity demand profiles. Analysis for the Florida warm season of 1982 indicates that the solar systems and heat recovery units operated with the highest efficiency while the heat pumps performed approximately twice as efficiently as the conventional electric water heaters. The average electrical demand profiles of the solar and heat recovery groups were considerably lower than those for the conventional and heat pump water heaters. The profiles of the latter two systems were similar although the heat pump sample used more hot water than the conventional group. When completed in 1983, the study data will provide a full year comparison of the energy savings and time-of-day impact of each DHW system type.

Merrigan, T.

1982-01-01

303

Hydrogen production from biogas using hot slag  

Microsoft Academic Search

Possibility of hydrogen production from biogas using hot slag has been studied, in which decomposition rate of CO2CH4 in a packed bed of granulated slag was measured at constant flow-rate and pressure. The molten slag, discharged at high temperature over 1700K from smelting industries such as steelmaking or municipal waste incineration. It has enough potential for replacing energy required for

Hadi Purwanto; Tomohiro Akiyama

2006-01-01

304

If Mars had hot-spots  

NASA Astrophysics Data System (ADS)

There are tantalizing clues to possible existence of outgassing sources, the hot-spots, on Mars. If confirmed, they would result in the presence of numerous chemical species "locally" that would otherwise go undetected in observations with poor spatial resolution. This paper is on the prediction of species that would form in the martian atmosphere following the outgassing from any possible hot-spots. Two sets of observations may imply the existence of regions of outgassing on Mars: a tentative detection of formaldehyde (CH2O) "locally", in the north equatorial spring, from the Phobos spacecraft in 1989 (Korablev, et al., Planet Space Sci. 41, 441, 1993), and indications of recent groundwater seepage and surface runoff particularly at middle and high martian latitudes (Malin and Edgett, Science, 288, 2330, 2000). The relatively short photochemical lifetime of 13 hrs for CH2 O in the martian atmosphererequires a "continuous" source of methane, whose oxidation provides the most efficient mechanism for producing formaldehyde. CH2O is an important precursor to the formation of complex hydrocarbons. Attempts to detect the species expected to be outgassed from the hot-spots or those that would form in the ensuing atmospheric chemistry have failed, perhaps because the observations were averaged over large areas, usually the disk or the hemisphere (the exception being the above local HCHO tentative detection). Considering the current disk-averaged upper limits of possible outgassed molecules including CH4 , SO2 , etc. and their possible enhancement over the hot-spots, we have developed chemical models to predict the abundances of new species that are expected to be formed in the Martian atmosphere locally. The Planetary Fourier Spectrometer on Mars Express appears well-suited for detecting many of the species.

Wong, A.; Atreya, S.

305

Hot Topics: Globalization and Climate Change  

E-print Network

experience the threat of nuclear fallout, sea level rise, air pollution, and industrial runoffall products of the global industrial system although the localities themselves have not produced nuclear bombs nor emitted vast quantities of greenhouse gases... growth that can yield both economic prosperity and no environmental damage (as expressed in the slogans win-wins, 161 Hot Topics: Globalization and Climate Change win-win-wins [the triple bottom line], and pollution prevention pays). In climate...

Malone, Elizabeth L.

2002-04-01

306

Virus silicification under simulated hot spring conditions.  

PubMed

Silicification of organisms in silica-depositing environments can impact both their ecology and their presence in the fossil record. Although microbes have been silicified under laboratory and environmental conditions, viruses have not. Bacteriophage T4 was successfully silicified under laboratory conditions that closely simulated those found in silica-depositing hot springs. Virus morphology was maintained, and a clear elemental signature of phosphorus was detected by energy-dispersive X-ray spectrophotometry (EDS). PMID:20735248

Laidler, James R; Stedman, Kenneth M

2010-01-01

307

Survey reveals hot-side precipitator performance  

Microsoft Academic Search

The survey has shown that hot-side precipitators may be susceptible to performance-related or structural-related problems. Performance-type problems are attributed to specific coal and ash characteristics. Structural-type problems may be attributed to inadequate provision for thermal expansion, operation above design temperatures, inadequate support structure design, or improper operational techniques. Although mechanical and instrumentation and control problems were reported, they are characteristic

G. M. Andes; W. E. Cummings

1983-01-01

308

Whistler Solitons in Plasma with Anisotropic Hot Electron Admixture  

NASA Technical Reports Server (NTRS)

The longitudinal and transverse modulation instability of whistler waves in plasma, with a small admixture of hot anisotropic electrons, is discussed. If the hot particles temperature anisotropy is positive, it is found that, in such plasma, longitudinal perturbations can lead to soliton formation for frequencies forbidden in cold plasma. The soliton is enriched by hot particles. The frequency region unstable to transverse modulation in cold plasma in the presence of hot electrons is divided by stable domains. For both cases the role of hot electrons is more significant for whistlers with smaller frequencies.

Khazanov, G. V.; Krivorutsky, E. N.; Gallagher, D. L.

1999-01-01

309

Toward improved durability in advanced aircraft engine hot sections  

NASA Technical Reports Server (NTRS)

The conference on durability improvement methods for advanced aircraft gas turbine hot-section components discussed NASA's Hot Section Technology (HOST) project, advanced high-temperature instrumentation for hot-section research, the development and application of combustor aerothermal models, and the evaluation of a data base and numerical model for turbine heat transfer. Also discussed are structural analysis methods for gas turbine hot section components, fatigue life-prediction modeling for turbine hot section materials, and the service life modeling of thermal barrier coatings for aircraft gas turbine engines.

Sokolowski, Daniel E. (editor)

1989-01-01

310

TWRS tank waste pretreatment process development hot test siting report  

SciTech Connect

This report is the sixth in a series that have assessed the hot testing requirements for TWRS pretreatment process development and identified the hot testing support requirements. This report, based on the previous work, identifies specific hot test work packages, matches those packages to specific hot cell facilities, and provides recommendations of specific facilities to be employed for the pretreatment hot test work. Also identified are serious limitations in the tank waste sample retrieval and handling infrastructure. Recommendations are provided for staged development of 500 mL, 3 L, 25 L and 4000 L sample recovery systems and specific actions to provide those capabilities.

Howden, G.F.; Banning, D.L.; Dodd, D.A.; Smith, D.A.; Stevens, P.F. [Westinghouse Hanford Co., Richland, WA (United States); Hansen, R.I.; Reynolds, B.A. [Pacific Northwest Lab., Richland, WA (United States)

1995-02-01

311

Fast cold gas in hot AGN outflows  

NASA Astrophysics Data System (ADS)

Observations of the emission from spatially extended cold gas around bright high-redshift quasars (QSOs) reveal surprisingly large velocity widths exceeding 2000 km s- 1, out to projected distances as large as 30 kpc. The high-velocity widths have been interpreted as the signature of powerful AGN-driven outflows. Naively, these findings appear in tension with hydrodynamic models in which AGN-driven outflows are energy-driven and thus very hot with typical temperatures T ? 106-7 K. Using the moving-mesh code AREPO, we perform `zoom-in' cosmological simulations of a z 6 QSO and its environment, following black hole growth and feedback via energy-driven outflows. In the simulations, the QSO host galaxy is surrounded by a clumpy circumgalactic medium pre-enriched with metals due to supernovae-driven galactic outflows. As a result, part of the AGN-driven hot outflowing gas can cool radiatively, leading to large amounts ( ? 109 M?) of cold gas comoving with the hot bipolar outflow. This results in velocity widths of spatially extended cold gas similar to those observed. We caution, however, that gas inflows, random motions in the deep potential well of the QSO host galaxy and cooling of supernovae-driven winds contribute significantly to the large velocity width of the cold gas in the simulations, complicating the interpretation of observational data.

Costa, Tiago; Sijacki, Debora; Haehnelt, Martin G.

2015-03-01

312

Sol Duc Hot Springs feasibility study  

SciTech Connect

Sol Duc Springs is located in the Olympic National Park in western Washington state. Since the turn of the century, the area has served as a resort, offering hot mineral baths, lodge and overnight cabin accommodations. The Park Service, in conjunction with the concessionaire, is in the process of renovating the existing facilities, most of which are approximately 50 years old. The present renovation work consists of removing all of the existing cabins and replacing them with 36 new units. In addition, a new hot pool is planned to replace the existing one. This report explores the possibility of a more efficient use of the geothermal resource to accompany other planned improvements. It is important to note that the system outlined is based upon the resource development as it exists currently. That is, the geothermal source is considered to be: the two existing wells and the hot springs currently in use. In addition, every effort has been made to accommodate the priorities for utilization as set forth by the Park Service.

Not Available

1981-12-01

313

Hot-hand bias in rhesus monkeys.  

PubMed

Human decision-makers often exhibit the hot-hand phenomenon, a tendency to perceive positive serial autocorrelations in independent sequential events. The term is named after the observation that basketball fans and players tend to perceive streaks of high accuracy shooting when they are demonstrably absent. That is, both observing fans and participating players tend to hold the belief that a player's chance of hitting a shot are greater following a hit than following a miss. We hypothesize that this bias reflects a strong and stable tendency among primates (including humans) to perceive positive autocorrelations in temporal sequences, that this bias is an adaptation to clumpy foraging environments, and that it may even be ecologically rational. Several studies support this idea in humans, but a stronger test would be to determine whether nonhuman primates also exhibit a hot-hand bias. Here we report behavior of 3 monkeys performing a novel gambling task in which correlation between sequential gambles (i.e., temporal clumpiness) is systematically manipulated. We find that monkeys have better performance (meaning, more optimal behavior) for clumped (positively correlated) than for dispersed (negatively correlated) distributions. These results identify and quantify a new bias in monkeys' risky decisions, support accounts that specifically incorporate cognitive biases into risky choice, and support the suggestion that the hot-hand phenomenon is an evolutionary ancient bias. (PsycINFO Database Record (c) 2014 APA, all rights reserved). PMID:25545977

Blanchard, Tommy C; Wilke, Andreas; Hayden, Benjamin Y

2014-07-01

314

CNO driven winds of hot first stars  

E-print Network

During the evolution of first stars, the CNO elements may emerge on their surfaces due to the mixing processes. Consequently, these stars may have winds driven purely by CNO elements. We study the properties of such stellar winds and discuss their influence on the surrounding environment. For this purpose, we used our own NLTE models and tested which stellar parameters of the first stars at different evolutionary stages result in CNO winds. If such winds are possible, we calculate their hydrodynamic structure and predict their parameters. We show that, while the studied stars do not have any wind driven purely by hydrogen and helium, CNO driven winds exist in more luminous stars. On the other hand, for very hot stars, CNO elements are too ionized to drive a wind. In most cases the derived mass-loss rate is much less than calculated with solar mixture of elements. This is because wind mass-loss rate in present hot stars is dominated by elements heavier than CNO. We conclude that, until a sufficient amount of these elements is created, the influence of line-driven winds is relatively small on the evolution of hot stars (which are not close to the Eddington limit).

Jiri Krticka; Jiri Kubat

2008-10-16

315

High temperature hot water distribution system study  

SciTech Connect

The existing High Temperature Hot Water (HTHW) Distribution System has been plagued with design and construction deficiencies since startup of the HTHW system, in October 1988. In October 1989, after one year of service, these deficiencies were outlined in a technical evaluation. The deficiencies included flooded manholes, sump pumps not hooked up, leaking valves, contaminated HTHW water, and no cathodic protection system. This feasibility study of the High Temperature Hot Water (HTHW) Distribution System was performed under Contract No. DACA0l-94-D-0033, Delivery Order 0013, Modification 1, issued to EMC Engineers, Inc. (EMC), by the Norfolk District Corps of Engineers, on 25 April 1996. The purpose of this study was to determine the existing conditions of the High Temperature Hot Water Distribution System, manholes, and areas of containment system degradation. The study focused on two areas of concern, as follows: * Determine existing conditions and areas of containment system degradation (leaks) in the underground carrier pipes and protective conduit. * Document the condition of underground steel and concrete manholes. To document the leaks, a site survey was performed, using state-of-the-art infrared leak detection equipment and tracer gas leak detection equipment. To document the condition of the manholes, color photographs were taken of the insides of 125 manholes, and notes were made on the condition of these manholes.

NONE

1996-12-01

316

Hot filament CVD of boron nitride films  

DOEpatents

Using a hot filament (.apprxeq.1400.degree. C.) to activate borazine (B.sub.3 N.sub.3 H.sub.6) molecules for subsequent reaction with a direct line-of-sight substrate, transparent boron ntiride films as thick as 25,000 angstroms are grown for a substrate temperature as low as 100.degree. C. The minimum temperature is determined by radiative heating from the adjacent hot filament. The low temperature BN films show no indication of crystallinity with X-ray diffraction (XRD). X-ray photoelectron spectra (XPS) show the films to have a B:N ratio of 0.97:1 with no other XPS detectable impurities above the 0.5% level. Both Raman and infrared (IR) spectroscopy are characteristic of h-BN with small amounts of hydrogen detected as N-H and B-H bands in the IR spectrum. An important feature of this method is the separation and localization of the thermal activation step at the hot filament from the surface reaction and film growth steps at the substrate surface. This allows both higher temperature thermal activation and lower temperature film growth.

Rye, Robert R. (Albuquerque, NM)

1992-01-01

317

Amorphous-silicon module hot-spot testing  

NASA Technical Reports Server (NTRS)

Hot spot heating occurs when cell short-circuit current is lower than string operating current. Amorphous cell hot spot are tested to develop the techniques required for performing reverse bias testing of amorphous cells. Also, to quantify the response of amorphous cells to reverse biasing. Guidelines are developed from testing for reducing hot spot susceptibility of amorphous modules and to develop a qualification test for hot spot testing of amorphous modules. It is concluded that amorphous cells undergo hot spot heating similarly to crystalline cells. Comparison of results obtained with submodules versus actual modules indicate heating levels lower in actual modules. Module design must address hot spot testing and hot spot qualification test conducted on modules showed no instabilities and minor cell erosion.

Gonzalez, C. C.

1985-01-01

318

Formation and X-ray emission from hot bubbles in planetary nebulae - I. Hot bubble formation  

NASA Astrophysics Data System (ADS)

We carry out high-resolution two-dimensional radiation-hydrodynamic numerical simulations to study the formation and evolution of hot bubbles inside planetary nebulae. We take into account the evolution of the stellar parameters, wind velocity and mass-loss rate from the final thermal pulses during the asymptotic giant branch (AGB) through to the post-AGB stage for a range of initial stellar masses. The instabilities that form at the interface between the hot bubble and the swept-up AGB wind shell lead to hydrodynamical interactions, photoevaporation flows and opacity variations. We explore the effects of hydrodynamical mixing combined with thermal conduction at this interface on the dynamics, photoionization, and emissivity of our models. We find that even models without thermal conduction mix significant amounts of mass into the hot bubble. When thermal conduction is not included, hot gas can leak through the gaps between clumps and filaments in the broken swept-up AGB shell and this depressurises the bubble. The inclusion of thermal conduction evaporates and heats material from the clumpy shell, which expands to seal the gaps, preventing a loss in bubble pressure. The dynamics of bubbles without conduction is dominated by the thermal pressure of the thick photoionized shell, while for bubbles with thermal conduction it is dominated by the hot, shocked wind.

Toal, J. A.; Arthur, S. J.

2014-10-01

319

Hot Particles of the Second Kind in Flood Lands of the Yenisei River  

Microsoft Academic Search

Specific modification of hot particles found in flood-land soils of the Yenisei River was studied. In contrast to the known hot particles (hot particles of the first kind), newly found hot particles are referred to as hot particles of the second kind. Abundance, radionuclide composition, and other characteristics of hot particles of the first and second kinds are compared.

Z. G. Gritchenko; Yu. V. Kuznetsov; V. K. Legin; V. N. Strukov; B. F. Myasoedov; A. P. Novikov; A. E. Shishlov; Yu. V. Savitskii

2001-01-01

320

Cold Friends of Hot Jupiters: AO Survey  

NASA Astrophysics Data System (ADS)

Hot Jupiters are a class of gas giant planets found in extrasolar systems at very small orbital distances (?0.05 AU). We know that these planets could not have formed at their present locations, but must instead have migrated in from beyond the ice line. One class of proposed migration mechanisms for these planets involve gravitational perturbations from a distant stellar companion. These same processes also provide a natural explanation for the existence of a subset of hot Jupiters that have been observed to have orbits that are highly misaligned with respect to their star's spin axis and/or have large orbital eccentricities. In the "Cold Friends" survey, we search for stellar companions around 51 stars known to host hot Jupiters in order to determine whether stellar companions play an important role in hot Jupiter migration. Our survey consists of a population of stars with planets that have eccentric and/or misaligned orbits as well as a control population of planets with well-aligned and circular orbits. This project searches for companion stars (the "Cold Friends") in three detection modes: radial velocity monitoring, high resolution IR spectroscopy (presented by D. Piskorz et al. at this meeting), and adaptive optics (AO) imaging at infrared wavelengths (presented here). The AO mode is sensitive to the most distant companions (separations of 50-200 AU and beyond) while the other modes are effective at finding companions at smaller separations. We present the results of our AO survey and discuss the binary fraction found in our sample. Out of our total sample of 51 stars, 19 candidate companions (many of which have not been observed before) were directly imaged around 17 stars. We also describe follow-up photometry and astrometry of all detected companions to determine whether or not they are gravitationally bound to the primary planet-hosting star. If such companions are common, it would suggest that perturbations from stellar companions may play a significant role in the evolution of hot Jupiter systems.

Ngo, Henry; Knutson, H. A.; Hinkley, S.; Crepp, J. R.; Batygin, K.; Howard, A. W.; Johnson, J. A.; Morton, T. D.; Muirhead, P. S.

2013-10-01

321

HOT CELL BUILDING, TRA632, INTERIOR. HOT CELL NO. 1 (THE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HOT CELL BUILDING, TRA-632, INTERIOR. HOT CELL NO. 1 (THE FIRST BUILT) IN LABORATORY 101. CAMERA FACES SOUTHEAST. SHIELDED OPERATING WINDOWS ARE ON LEFT (NORTH) SIDE. OBSERVATION WINDOW IS AT LEFT OF VIEW (ON WEST SIDE). PLASTIC COVERS SHROUD MASTER/SLAVE MANIPULATORS AT WINDOWS IN LEFT OF VIEW. NOTE MINERAL OIL RESERVOIR ABOVE "CELL 1" SIGN, INDICATING LEVEL OF THE FLUID INSIDE THE THICK WINDOWS. HOT CELL HAS BEVELED CORNER BECAUSE A SQUARED CORNER WOULD HAVE SUPPLIED UNNECESSARY SHIELDING. NOTE PUMICE BLOCK WALL AT LEFT OF VIEW. INL NEGATIVE NO. HD46-28-1. Mike Crane, Photographer, 2/2005 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

322

Organic Molecules in the Galactic Center. Hot Core Chemistry without Hot Cores  

E-print Network

We study the origin of large abundances of complex organic molecules in the Galactic center (GC). We carried out a systematic study of the complex organic molecules CH3OH, C2H5OH, (CH3)2O, HCOOCH3, HCOOH, CH3COOH, H2CO, and CS toward 40 GC molecular clouds. Using the LTE approximation, we derived the physical properties of GC molecular clouds and the abundances of the complex molecules.The CH3OH abundance between clouds varies by nearly two orders of magnitude from 2.4x10^{-8} to 1.1x10^{-6}. The abundance of the other complex organic molecules relative to that of CH3OH is basically independent of the CH3OH abundance, with variations of only a factor 4-8. The abundances of complex organic molecules in the GC are compared with those measured in hot cores and hot corinos, in which these complex molecules are also abundant. We find that both the abundance and the abundance ratios of the complex molecules relative to CH3OH in hot cores are similar to those found in the GC clouds. However, hot corinos show different abundance ratios than observed in hot cores and in GC clouds. The rather constant abundance of all the complex molecules relative to CH3OH suggests that all complex molecules are ejected from grain mantles by shocks. Frequent (similar 10^{5}years) shocks with velocities >6km/s are required to explain the high abundances in gas phase of complex organic molecules in the GC molecular clouds. The rather uniform abundance ratios in the GC clouds and in Galactic hot cores indicate a similar average composition of grain mantles in both kinds of regions. The Sickle and the Thermal Radio Arches, affected by UV radiation, show different relative abundances in the complex organic molecules due to the differentially photodissociation of these molecules.

M. A. Requena-Torres; J. Martn-Pintado; A. Rodrguez-Franco; S. Martn; N. J. Rodrguez-Fernndez; P. de Vicente

2006-05-18

323

HOT CELL BUILDING, TRA632. CONTEXTUAL AERIAL VIEW OF HOT CELL ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HOT CELL BUILDING, TRA-632. CONTEXTUAL AERIAL VIEW OF HOT CELL BUILDING, IN VIEW AT LEFT, AS YET WITHOUT ROOF. PLUG STORAGE BUILDING LIES BETWEEN IT AND THE SOUTH SIDE OF THE MTR BUILDING AND ITS WING. NOTE CONCRETE DRIVE BETWEEN ROLL-UP DOOR IN MTR BUILDING AND CHARGING FACE OF PLUG STORAGE. REACTOR SERVICES BUILDING (TRA-635) WILL COVER THIS DRIVE AND BUTT UP TO CHARGING FACE. DOTTED LINE IS ON ORIGINAL NEGATIVE. TRA PARKING LOT IN LEFT CORNER OF THE VIEW. CAMERA FACING NORTHWESTERLY. INL NEGATIVE NO. 8274. Unknown Photographer, 7/2/1953 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

324

HOT CELL BUILDING, TRA632, INTERIOR. DETAIL OF HOT CELL NO. ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

HOT CELL BUILDING, TRA-632, INTERIOR. DETAIL OF HOT CELL NO. 2 SHOWS MANIPULATION INSTRUMENTS AND SHIELDED OPERATING WINDOWS. PENETRATIONS FOR OPERATING INSTRUMENTS GO THROUGH SHIELDING ABOVE WINDOWS. CONDUIT FOR UTILITIES AND CONTROLS IS BEHIND METAL CABINET BELOW WINDOWS NEAR FLOOR. CAMERA FACES WEST. WARNING SIGN LIMITS FISSILE MATERIAL TO SPECIFIED NUMBER OF GRAMS OF URANIUM AND PLUTONIUM. INL NEGATIVE NO. HD46-28-2. Mike Crane, Photographer, 2/2005 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

325

An evaluation of lead concentrations in imported hot sauces.  

PubMed

In the last decade, the U.S. Food and Drug Administration (FDA) has issued several warnings and recalls for food products that exceed FDA standards for lead. Products containing chili peppers and salt were often suspected as sources of lead contamination, and included items such as candy that are routinely investigated. However, products such as hot sauces that contain similar ingredients have not been the focus of evaluations. This study quantified lead concentrations in imported hot sauces, evaluated product compliance to existing United States standards, and calculated potential dietary lead exposure for children using the Integrated Exposure Uptake Biokinetic Model. Finally, recommendations for reducing the risk of lead exposure from hot sauces are provided. Twenty-five (25) bottles of imported hot sauces manufactured in Mexico and South America were purchased in Clark County, Nevada. All hot sauces were analyzed for lead concentrations, pH, and leaded packaging. Hot sauces were analyzed by inductively coupled plasma mass spectrometry and packaging was analyzed using x-ray fluorescence technology. Four brands of hot sauces (16%) exceeded 0.1 ppm lead, the current FDA action level for lead in candy. Hot sauces with lead concentrations >0.1 ppm lead contained salt and were manufactured in Mexico. Subsequent analysis of additional lots of hot sauces exceeding 0.1 ppm lead revealed inconsistent lead concentrations between and within manufacturer lots. The lead concentrations of the plastic hot sauce lids ranged from below the limit of detection to 2,028 ppm lead. There was no association between lead concentrations in hot sauces and pepper type. These results indicate the need for more rigorous screening protocols for products imported from Mexico, the establishment of an applicable standard for hot sauce, and resources to allow for the enforcement of existing food safety policies. The data reported herein represent the first known investigation of lead concentrations in hot sauces. PMID:23581685

Berger Ritchie, Jennifer A; Gerstenberger, Shawn L

2013-01-01

326

Nucleosynthesis in Hot and Dense Media  

E-print Network

We study the finite temperature and density effects on beta decay rates to compute their contributions to nucleosynthesis. QED type corrections to beta decay from the hot and dense background are estimated in terms of the statistical corrections to the self-mass of an electron. For this purpose, we re-examine the hot and dense background contributions to the electron mass and compute its effect to the beta decay rate, helium yield, energy density of the universe as well as the change in neutrino temperature from the first order contribution to the self-mass of electrons during these processes. We explicitly show that the thermal contribution to the helium abundance at T = m of a cooling universe 0.045 % is higher than the corresponding contribution to helium abundance of a heating universe 0.031% due to the existence of hot fermions before the beginning of nucleosynthesis and their absence after the nucleosynthesis, in the early universe. Thermal contribution to helium abundance was a simple quadratic function of temperature, before and after the nucleosynthesis. However, this quadratic behavior was not the same before the decoupling temperature due to weak interactions; so the nucleosynthesis did not even start before the universe had cooled down to the neutrino decoupling temperatures and QED became a dominant theory. It is also explicitly shown that the chemical potential in the core of supermassive and superdense stars affect beta decay and their helium abundance but the background contributions depend on the ratio between temperature and chemical potential and not the chemical potential or temperature only. It has been noticed that temperature plays a role of regulating parameter in an extremely dense systems.

Samina S. Masood

2014-05-06

327

Hot Gaseous Halos of Nearby Disk Galaxies  

E-print Network

I review studies of the hot gaseous medium in and around nearby normal disk galaxies, including the Milky Way. This medium represents a reservoir of materials required for lasting star formation, a depository of galactic feedback (e.g., stellar mass loss and supernovae), and an interface between the interstellar and intergalactic media. Important progress has been made recently with the detection of X-ray absorption lines in the spectra of X-ray binaries and AGNs. The X-ray absorption line spectroscopy, together with existing X-ray emission and far-UV \\ovi absorption measurements now allows for the first time to characterize the global spatial, thermal, and chemical properties of hot gas in the Galaxy. The results are generally consistent with those inferred from X-ray imaging of nearby edge-on galaxies similar to the Milky Way. Observed diffuse X-ray emitting/absorbing gas does not extend significantly more than $\\sim 10$ kpc away from galactic disks/bulges, except in nuclear starburst or very massive galaxies. The X-ray cooling rate of this gas is generally far less than the expected supernova mechanical energy input alone. So the bulk of the energy is ``missing''. On the other hand, evidence for a large-scale ($\\gsim 10^2$ kpc) hot gaseous halo around the Milky Way to explain various high-velocity clouds is mounting. The theoretical argument for ongoing accretion of intergalactic gas onto disk galaxies is also compelling. I discuss possible solutions that reconcile these facts.

Q. Daniel Wang

2006-11-01

328

Method for hot press forming articles  

DOEpatents

This disclosure relates to an improved method for achieving the best bond strength and for minimizing distortion and cracking of hot pressed articles. In particular, in a method for hot press forming both an outer facing circumferential surface of and an inner portion of a hub, and of bonding that so-formed outer facing circumferential surface to an inner facing circumferential surface of a pre-formed ring thereby to form an article, the following improvement is made. Normally, in this method, the outside ring is restrained by a restraining sleeve of ring-shaped cross-section having an inside diameter. A die member, used to hot press form the hub, is so-formed as to have an outside diameter sized to engage the inside diameter of the restraining sleeve in a manner permitting relative movement therebetween. The improved method is one in which several pairs of matched restraining sleeve and die member are formed with each matched pair having a predetermined diameter. The predetermined diameter of each matched pair is different from another matched pair by stepped increments. The largest inside diameter of a restraining sleeve is equal to the diameter of the outer facing circumferential surface of the hub. Each pair of the matched restraining sleeve and die member is used to form an article in which an inside hub is bonded to an outside ring. The several samples so-formed are evaluated to determine which sample has the best bond formed between the hub and the ring with the least or no cracking or distortion in the ring portion of the article. Thereafter, the matched restraining sleeve and die member which form the article having the best bonding characteristics and least distortion cracking is then used for repeated formations of articles.

Baker, Robert R. (Livonia, MI); Hartsock, Dale L. (Livonia, MI)

1982-01-01

329

Hot electron transport and current sensing  

NASA Astrophysics Data System (ADS)

The effect of hot electrons on momentum scattering rates in a two-dimensional electron gas is critically examined. It is shown that with hot electrons it is possible to explore the temperature dependence of individual scattering mechanisms not easily probed under equilibrium conditions; both the Bloch-Gruneisen (BG) phonon scattering phenomena and the reduction in impurity scattering are clearly observed. The theoretical calculations are consistent with the results obtained from hot electrons experiments. As a function of bias current, a resistance peak is formed in a 2DEG if the low temperature impurity limited mobilities muI( T = 0) is comparable to muph(TBG ) the phonon limited mobility at the critical BG temperature. In this case, as the bias current is increased, the electron temperature Te rises due to Joule heating and the rapid increase in phonon scattering can be detected before the effect of the reduction in impurity scattering sets in. If muI(T = 0) << muph(TBG), there is no peak in resistance because the impurity scattering dominates sufficiently and its reduction has a much stronger effect on the total resistance than the rise in phonon scattering. Furthermore, knowing the momentum relaxation rates allows us to analyze the possible interplay between electron-electron and electron-boundary scattering. The prediction that a Knudsen to Poiseuille (KP) transition similar to that of a classical gas can occur in electron flow [26] is examined for the case of a wire defined in a 2DEG. Concurrently, an appropriate current imaging technique to detect this transition is sought. A rigorous evaluation of magnetic force microscopy (MFM) as a possible candidate to detect Poiseuille electronic flow was conducted, and a method that exploits the mechanical resonance of the MFM cantilever was implemented to significantly improve its current sensitivity.

Abraham, Mathew Cheeran

330

Chemical Constraints on Hot Jupiter Migration  

NASA Astrophysics Data System (ADS)

The origin of close-in giant exoplanets is a long-standing puzzle. Planet formation theories suggest that such planets are unlikely to have formed in-situ but instead may have formed at large orbital separations beyond the snow line and migrated inward to their present orbits. Two competing hypotheses suggest that the planets migrated either through interaction with the protoplanetary disk during their formation, or by disk-free mechanisms such as gravitational interactions with a third body. Observations of eccentricities and spin-orbit misalignments of hot Jupiter systems have been unable to differentiate between the two hypotheses. In the present work, we show that chemical abundances of exoplanetary atmospheres may be used to constrain their formation and/or migration mechanisms. We use spectroscopic observations, obtained using HST, Spitzer, and ground-based facilities, of several giant exoplanets to derive stringent constraints on their atmospheric C and O abundances. We then use the chemical abundances along with planet formation models to place the first rigorous constraints on the formation and migration pathways of the exoplanets in our sample. Our results suggest in particular that chemical depletions in hot Jupiter atmospheres have the potential to constrain their migration mechanisms which have thus far remained elusive based on dynamical measurements. We find that sub-solar carbon and oxygen abundances in Jovian-mass hot Jupiters around Sun-like stars are hard to explain by disk migration. Instead, such abundances are more readily explained by giant planets forming at large orbital separations, either by core accretion or gravitational instability, and migrating to close-in orbits via disk-free mechanisms involving dynamical encounters. Our results open a new means for understanding the origins of exoplanets which have thus far been investigated based largely on dynamical properties of their orbits. We will discuss several open questions in this new frontier.

Madhusudhan, Nikku; Amin, Mustafa A.; Kennedy, Grant M.

2015-01-01

331

Characterizing hot spots throughout the catchment  

NASA Astrophysics Data System (ADS)

Few catchments in the world are left truly undisturbed. Rather, they are under anthropogenic stress for a variety of reasons ranging from climate forcing to meeting the basic water allocation needs of the population. Reduction in the number of inundation areas has significantly decreased the nutrient and organic matter retention capacity along the river corridor, with major consequences for the both the riverine and coastal ecosystems. Cumulative stress may build up to a "tipping point" which can cause a change or set of changes which could occur non-linearly. In order to mitigate the environmental stress on these ecosystems, management plans are created to balance the needs of the dependent populations and those of ecology. While these catchment-wide plans aim to improve the ecological function of aquatic areas over the large scale, this sledge-hammer approach ignores the inherent heterogeneity in the catchment. Societal (and policy) decisions involve more than abiotic quantification of water storage and flow. A more encompassing ecohydrological view facilitates a more rounded policy framework that has flexibility to accommodate multiple social drivers, and one that can accommodate an "ecosystem improvement" rather than single species improvement. Not every spot in the landscape is equally valuable for specific societal values. Areas of high activity may provide the resilience capacity necessary to prevent catastrophic changes. In times of ecological instability, ecosystem resilience is of paramount importance in maintaining essential ecosystem services. Hot spots of biogeochemical cycling will occur where unique situations arise, such as areas of surface and groundwater interaction, creating spots of localized, high activity. In order to understand the systems' potential to support various habitat niches in the large scale, the identification of specific hot spots or hot moments is necessary. A basal understanding of the concurrent biogeochemical cycles enables the subsequent predictions of the alternative ecosystem responses. This study aims to understand the where and why of hot spots in selected catchments in southeastern Australia and Midwestern United States. The ecosystem response to changes in the catchment will be generated based on various biotic parameters, with the ultimate goal of incorporation into a policy framework at the catchment scale.

Welti, N.; Lockington, D.; Jakeman, T.; Hunt, R.

2012-04-01

332

Optical Precursor in Hot Rubidium Vapor  

NASA Astrophysics Data System (ADS)

A pico-second pulse with center wavelength about 795nm was sent through a hot rubidium (Rb) cell. The output pulse was detected by a streak camera with 2 pico-second resolution. The experiment data showed the original pulse separates to a main pulse and a precursor which travels faster than the main pulse. This gives some experiment evidence of the formation of precursor when a step-function-shape electromagnetic pulse travels through a Lorentz absorber, which was proposed by Dr. A. Sommerfeld and Dr. L. Brillouin about 100 years ago.

Yang, Wenlong; Springer, Matthew; Kolomenski, Alexandre; Kattawar, George; Sokolov, Alexei

2010-03-01

333

When hot water freezes before cold  

E-print Network

I suggest that the origin of the Mpemba effect (the freezing of hot water before cold) is freezing-point depression by solutes, either gaseous or solid, whose solubility decreases with increasing temperature so that they are removed when water is heated. They are concentrated ahead of the freezing front by zone refining in water that has not been heated, reduce the temperature of the freezing front, and thereby reduce the temperature gradient and heat flux, slowing the progress of the front. I present a simple calculation of this effect, and suggest experiments to test this hypothesis.

J. I. Katz

2006-04-27

334

Ion diffusion at interfaces in hot plasmas  

SciTech Connect

There are many laboratory applications in which it is important to know how fast two hot, ionized materials mix across an initially sharp interface. The speed of this process is regulated by the interdiffusion coefficient for the species involved. In a previous work, a theoretical method for calculating the interdiffusion coefficient in a Binary Ionic Mixture (classical ions in a uniform, neutralizing background) was described and found to give excellent agreement with Molecular Dynamics estimates. The purpose of this report is to show how these results may be applied to a model of the plasma interface, including electric field effects, to give a good description of the mixing across it.

Boercker, D.B.; Warren, K.; Haggin, G.

1986-04-01

335

Hot air drum evaporator. [Patent application  

DOEpatents

An evaporation system for aqueous radioactive waste uses standard 30 and 55 gallon drums. Waste solutions form cascading water sprays as they pass over a number of trays arranged in a vertical stack within a drum. Hot dry air is circulated radially of the drum through the water sprays thereby removing water vapor. The system is encased in concrete to prevent exposure to radioactivity. The use of standard 30 and 55 gallon drums permits an inexpensive compact modular design that is readily disposable, thus eliminating maintenance and radiation build-up problems encountered with conventional evaporation systems.

Black, R.L.

1980-11-12

336

Hot Fuel Examination Facility/South  

SciTech Connect

This document describes the potential environmental impacts associated with proposed modifications to the Hot Fuel Examination Facility/South (HFEF/S). The proposed action, to modify the existing HFEF/S at the Argonne National Laboratory-West (ANL-W) on the Idaho National Engineering Laboratory (INEL) in southeastern Idaho, would allow important aspects of the Integral Fast Reactor (IFR) concept, offering potential advantages in nuclear safety and economics, to be demonstrated. It would support fuel cycle experiments and would supply fresh fuel to the Experimental Breeder Reactor-II (EBR-II) at the INEL. 35 refs., 12 figs., 13 tabs.

Not Available

1990-05-01

337

The flying hot wire and related instrumentation  

NASA Technical Reports Server (NTRS)

A flying hot-wire technique is proposed for studies of separated turbulent flow in wind tunnels. The technique avoids the problem of signal rectification in regions of high turbulence level by moving the probe rapidly through the flow on the end of a rotating arm. New problems which arise include control of effects of torque variation on rotor speed, avoidance of interference from the wake of the moving arms, and synchronization of data acquisition with rotation. Solutions for these problems are described. The self-calibrating feature of the technique is illustrated by a sample X-array calibration.

Coles, D.; Cantnell, B.; Wadcock, A.

1978-01-01

338

HotRecorder 2.0.1  

NSDL National Science Digital Library

When having online conversations, sometimes a mere emoticon just won't do. For those who are looking to add a bit of variety to such social interactions, there is the HotRecorder application. With this program, users can record and add "emotisounds" to voice communications that take place over the Internet. The program works in conjunction with a number of such communication tools, including Skype, Google Talk and Yahoo Messenger 7. Other helpful features include a number of recording tools and some detailed search features. This application is compatible with Windows XP/2003 server.

339

Control apparatus for hot gas engine  

DOEpatents

A mean pressure power control system for a hot gas (Stirling) engine utilizing a plurality of supply tanks for storing a working gas at different pressures. During pump down operations gas is bled from the engine by a compressor having a plurality of independent pumping volumes. In one embodiment of the invention, a bypass control valve system allows one or more of the compressor volumes to be connected to the storage tanks. By selectively sequencing the bypass valves, a capacity range can be developed over the compressor that allows for lower engine idle pressures and more rapid pump down rates.

Stotts, Robert E. (Clifton Park, NY)

1986-01-01

340

Multiple volume compressor for hot gas engine  

DOEpatents

A multiple volume compressor for use in a hot gas (Stirling) engine having a plurality of different volume chambers arranged to pump down the engine when decreased power is called for and return the working gas to a storage tank or reservoir. A valve actuated bypass loop is placed over each chamber which can be opened to return gas discharged from the chamber back to the inlet thereto. By selectively actuating the bypass valves, a number of different compressor capacities can be attained without changing compressor speed whereby the capacity of the compressor can be matched to the power available from the engine which is used to drive the compressor.

Stotts, Robert E. (Clifton Park, NY)

1986-01-01

341

A Versatile Rocket Engine Hot Gas Facility  

NASA Technical Reports Server (NTRS)

The capabilities of a versatile rocket engine facility, located in the Rocket Laboratory at the NASA Lewis Research Center, are presented. The gaseous hydrogen/oxygen facility can be used for thermal shock and hot gas testing of materials and structures as well as rocket propulsion testing. Testing over a wide range of operating conditions in both fuel and oxygen rich regimes can be conducted, with cooled or uncooled test specimens. The size and location of the test cell provide the ability to conduct large amounts of testing in short time periods with rapid turnaround between programs.

Green, James M.

1993-01-01

342

6.NS Making Hot Cocoa, Variation 1  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: One mug of hot chocolate uses $\\frac23$ cup of cocoa powder. How many mugs can Nelli make with 3 cups of cocoa powder? Solve the problem by drawing a p...

343

6.NS Making Hot Cocoa, Variation 2  

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: A recipe for hot chocolate calls for 3 cups of milk. What fraction of the recipe can Nelli make with $\\frac23$ cups of milk? Solve the problem by drawi...

344

Hot Colors- Windows into Hidden Worlds  

NSDL National Science Digital Library

This website contains an electronic field trip based on Yellowstone National Park's hot springs and the microorganisms living in them. The site includes a link for teachers providing an introduction, overview of concepts explored in the trip, lesson plans, and additional web links. The electronic field trip may be viewed in a low bandwidth version without downloading. For a high bandwith version of the field trip, Macromedia Flash Player is required and can be downloaded on site. Further information on system requirements and field trip procedures are outlined on the website as well.

Foundation, Thermal B.; Foundation, Yellowstone P.

345

Automated inspection of hot steel slabs  

DOEpatents

The disclosure relates to a real time digital image enhancement system for performing the image enhancement segmentation processing required for a real time automated system for detecting and classifying surface imperfections in hot steel slabs. The system provides for simultaneous execution of edge detection processing and intensity threshold processing in parallel on the same image data produced by a sensor device such as a scanning camera. The results of each process are utilized to validate the results of the other process and a resulting image is generated that contains only corresponding segmentation that is produced by both processes.

Martin, Ronald J. (Burnsville, MN)

1985-01-01

346

Automated inspection of hot steel slabs  

DOEpatents

The disclosure relates to a real time digital image enhancement system for performing the image enhancement segmentation processing required for a real time automated system for detecting and classifying surface imperfections in hot steel slabs. The system provides for simultaneous execution of edge detection processing and intensity threshold processing in parallel on the same image data produced by a sensor device such as a scanning camera. The results of each process are utilized to validate the results of the other process and a resulting image is generated that contains only corresponding segmentation that is produced by both processes. 5 figs.

Martin, R.J.

1985-12-24

347

Hot cell shield plug extraction apparatus  

DOEpatents

An apparatus is provided for moving shielding plugs into and out of holes in concrete shielding walls in hot cells for handling radioactive materials without the use of external moving equipment. The apparatus provides a means whereby a shield plug is extracted from its hole and then swung approximately 90 degrees out of the way so that the hole may be accessed. The apparatus uses hinges to slide the plug in and out and to rotate it out of the way, the hinge apparatus also supporting the weight of the plug in all positions, with the load of the plug being transferred to a vertical wall by means of a bolting arrangement.

Knapp, Philip A. (Moore, ID); Manhart, Larry K. (Pingree, ID)

1995-01-01

348

Hot electron injection driven phase transitions  

NASA Astrophysics Data System (ADS)

We report on a general mechanism for photo-induced phase transitions. The process relies on the photo-injection of hot electrons from an adjacent metallic layer to trigger the structural dynamics of the materials of interest. This mechanism is demonstrated for the semiconductor-to-metal phase transition of VO2 using a 20 nm Au injection layer. The nature of the phase transition is demonstrated by time-resolved optical transmission measurements, as well as a well defined bias dependence that illustrates that the Au film is the source of nonequilibrium electrons driving the phase transition.

Hada, Masaki; Zhang, Dongfang; Casandruc, Albert; Miller, R. J. Dwayne; Hontani, Yusaku; Matsuo, Jiro; Marvel, Robert E.; Haglund, Richard F., Jr.

2012-10-01

349

[PFBC Hot Gas Cleanup Test Program  

SciTech Connect

Four hundred and fifty four clay bonded silicon carbide Schumacher Dia Schumalith candle filters were purchased for installation in the Westinghouse Advanced Particle Filtration (APF) system at the American Electric Power (AEP) plant in Brilliant, Ohio. A surveillance effort has been identified which will monitor candle filter performance and life during hot gas cleaning in AEP's pressurized fluidized-bed combustion system. A description of the candle surveillance program, strategy for candle filter location selection, as well as candle filter post-test characterization is provided in this memo. The period of effort for candle filter surveillance monitoring is planned through March 1994.

Not Available

1992-10-01

350

Particulate hot gas stream cleanup technical issues  

SciTech Connect

The analyses of hot gas stream cleanup particulate samples and descriptions of filter performance studied under this contract were designed to address problems with filter operation that have been linked to characteristics of the collected particulate matter. One objective of this work was to generate an interactive, computerized data bank of the key physical and chemical characteristics of ash and char collected from operating advanced particle filters and to relate these characteristics to the operation and performance of these filters. The interactive data bank summarizes analyses of over 160 ash and char samples from fifteen pressurized fluidized-bed combustion and gasification facilities utilizing high-temperature, high pressure barrier filters.

Pontius, D.H.; Snyder, T.R.

1999-09-30

351

Organic Molecules in the Galactic Center. Hot Core Chemistry without Hot Cores  

E-print Network

To study the origin of the large abundances of complex organic molecules in the Galactic center (GC), we have carried out a systematic study of the complex organic molecules CH3OH, C2H5OH, (CH3)2O, HCOOCH3, HCOOH, CH3COOH, H2CO and CS toward 40 GC molecular clouds. Using the LTE approximation, we have derived the physical properties of GC molecular clouds and the abundances of the complex molecules.The CH3OH abundance between clouds varies by nearly two orders of magnitude from 2.4x10^{-8} to 1.1x10^{-6}. The abundance of the other complex organic molecules relative to that of CH3OH is basically independent of the CH3OH abundance, with variations of only a factor of 4-8. The abundances of complex organic molecules in the GC are compared with those measured in hot cores and hot corinos, in which these complex molecules are also abundant. We find that both the abundance and the abundance ratios of the complex molecules relative to CH3OH in hot cores are similar to that found in the GC clouds. However, hot corin...

Requena-Torres, M A; Martn, S; Martn-Pintado, J; Rodr'iguez-Fern'andez, N J; Rodrguez-Franco, A

2006-01-01

352

Hot Strange Stars. I. Equation of State of Hot Strange Quark Matter  

NASA Astrophysics Data System (ADS)

An equation of state for hot quark matter is derived on the basis of the MIT bag model. It is shown that the pressure at constant energy density depends weakly on the temperature T for 0 ? T ?100 MeV. In contrast to this, the pressure for a constant quark density increases significantly with rising temperature.

Hajyan, G. S.; Alaverdyan, A. G.

2014-12-01

353

Hot dry rock geothermal potential of Roosevelt Hot Springs area: review of data and recommendations  

SciTech Connect

The Roosevelt Hot Springs area in west-central Utah possesses several features indicating potential for hot dry rock (HDR) geothermal development. The area is characterized by extensional tectonics and a high regional heat flow of greater than 105 mW/m/sup 2/. The presence of silicic volcanic rocks as young as 0.5 to 0.8 Myr and totaling 14 km/sup 3/ in volume indicates underlying magma reservoirs may be the heat source for the thermal anomaly. Several hot dry wells have been drilled on the periphery of the geothermal field. Information obtained on three of these deep wells shows that they have thermal gradients of 55 to 60/sup 0/C/km and bottom in impermeable Tertiary granitic and Precambrian gneissic units. The Tertiary granite is the preferred HDR reservoir rock because Precambrian gneissic rocks possess a well-developed banded foliation, making fracture control over the reservoir more difficult. Based on a fairly conservative estimate of 160 km/sup 2/ for the thermal anomaly present at Roosevelt Hot Springs, the area designated favorable for HDR geothermal exploration may be on the order of seven times or more than the hydrogeothermal area currently under development.

East, J.

1981-05-01

354

Burnout protection of a hot-wire anemometer  

Microsoft Academic Search

A burnout protection circuit which will prevent hot-wire overloading is described. The transient response of a hot-wire system to power loading is examined. Two methods for preventing the overloading of the hot-wire system are: (1) to start the positive power earlier than the negative power or (2) to slowly start the power transistor after the bipolar powers are imposed on

S. Takagi

1990-01-01

355

Hot-electron reliability and ESD latent damage  

Microsoft Academic Search

The impact of noncatastrophic electrostatic discharge (ESD) stress on hot-electron reliability as well as the effect of hot-electron (HE) injection on the ESD protection threshold are discussed. It is found that there is a factor-of-two-to-four deterioration in hot-electron reliability after low-level ESD stress. These two effects can be viewed as similar although HE is a low-current long-time process and ESD

Shian Aur; Amitava Chatterjee; Thomas Polgreen

1988-01-01

356

DECOMMISSIONING OF HOT CELL FACILITIES AT THE BATTELLE COLUMBUS LABORATORIES  

SciTech Connect

Battelle Columbus Laboratories (BCL), located in Columbus, Ohio, must complete decontamination and decommissioning activities for nuclear research buildings and grounds at its West Jefferson Facilities by 2006, as mandated by Congress. This effort includes decommissioning several hot cells located in the Hot Cell Laboratory (Building JN-1). JN-1 was originally constructed in 1955, and a hot cell/high bay addition was built in the mid 1970s. For over 30 years, BCL used these hot cell facilities to conduct research for the nuclear power industry and several government agencies, including the U.S. Navy, U.S. Army, U.S. Air Force, and the U.S. Department of Energy. As a result of this research, the JN-1 hot cells became highly contaminated with mixed fission and activation products, as well as fuel residues. In 1998, the Battelle Columbus Laboratories Decommissioning Project (BCLDP) began efforts to decommission JN-1 with the goal of remediating the site to levels of residual contamination allowing future use without radiological restrictions. This goal requires that each hot cell be decommissioned to a state where it can be safely demolished and transported to an off-site disposal facility. To achieve this, the BCLDP uses a four-step process for decommissioning each hot cell: (1) Source Term Removal; (2) Initial (i.e., remote) Decontamination; (3) Utility Removal; and (4) Final (i.e., manual) Decontamination/Stabilization. To date, this process has been successfully utilized on 13 hot cells within JN-1, with one hot cell remaining to be decommissioned. This paper will provide a case study of the hot cell decommissioning being conducted by the BCLDP. Discussed will be the methods used to achieve the goals of each of the hot cell decommissioning stages and the lessons learned that could be applied at other sites where hot cells need to be decommissioned.

Weaver, Patrick; Henderson, Glenn; Erickson, Peter; Garber, David

2003-02-27

357

Design package for solar domestic hot water system  

SciTech Connect

Information used to evaluate the initial design of the Elcam, Inc., Solar Domestic Hot Water System is presented. Included are such items as the system performance specification, detailed design drawings and other information. Elcam, Inc., has developed two solar heated prototype hot water systems and two heat exchangers. The hot water systems consist of the following subsystems: collector, storage, control, transport, auxiliary energy, and government-furnished Site Data Acquisition. The two systems are installed at Tempe, Arizona, and San Diego, California.

None

1980-09-01

358

Development of NDE methods for hot gas filters  

Microsoft Academic Search

Ceramic hot gas candle filters are currently under development for hot gas particulate cleanup in advanced coal-based power systems. The ceramic materials for these filters include nonoxide monolithic, nonoxide-fiber-reinforced composites, and nonoxide reticulated foam. A concern is the lack of reliable data on which to base decisions for reusing or replacing hot gas filters during plant shutdowns. The work in

C. Deemer; W. A. Ellingson; E. R. Koehl; H. Lee; T. Spohnholtz; J. G. Sun

1999-01-01

359

Hot embossing - The molding technique for plastic microstructures  

Microsoft Academic Search

Hot embossing is the technique to fabricate high precision and high quality plastic microstructures. Industrial fabrication\\u000a of plastics components is normally achieved by injection molding. Hot embossing is actually used only for a few optical applications\\u000a where high precision and high quality are important.\\u000a \\u000a The advantages of hot embossing are low material flow, avoiding internal stress which induces e.g. scattering

M. Heckele; W. Bacher; K. D. Mller

1998-01-01

360

Hot cell facility design for large fusion devices  

SciTech Connect

Large hot cell facilities will be necessary to support the operation of large fusion devices. The supporting hot cells will be needed to serve a variety of different functions and tasks, which include reactor component maintenance, tool and maintenance equipment repair, and preparation of radioactive material for shipment and disposal. This paper discusses hot cell facility functions, requirements, and design issues and techniques. Suggested solutions and examples are given.

Barrett, R.J.; Bussell, G.T.

1985-01-01

361

Characterizing the Hot Kepler Objects of Interest  

NASA Astrophysics Data System (ADS)

Planets around retired A stars (hot stars that have evolved off the main sequence) have large semimajor axes compared to planets around sun-like stars (e.g. Johnson et al. 2007, Bowler et al. 2010). This could be a side effect of the stars' evolution; increases in tidal dissipation as the stars evolve and expand may lead to the orbital decay and eventual destruction of close-in planets. Alternatively, differences in planet formation processes around these more massive stars may account for their lack of hot Jupiters. To distinguish between these two possibilities, we characterize main sequence A stars with transiting planet candidates detected by Kepler. We identify likely A stars in the Kepler Input Catalog (KIC) by their stellar effective temperatures, derived from KIC grizJHK photometry using the empirical relations from Boyajian et al. (2013). To verify the classification of a subset of these stars, we measure their spectra using Palomar DBSP and collect high-resolution images with Keck NIRC2. We determine the physical parameters of the transiting planets orbits by fitting the Kepler transit lightcurves with Markov Chain Monte Carlo methods. By constraining the semi-major axis and eccentricity distributions of planets orbiting A stars, we gain insights into the role of stellar evolution and stellar mass in planetary systems.

Rogers, Leslie; Price, E.; Shporer, A.; Crepp, J. R.; Swift, J.; Muirhead, P. S.; Johnson, J. A.

2014-01-01

362

Numerical simulation of hot-electron phenomena  

SciTech Connect

An accurate two-dimensional numerical model for MOS transistors incorporating avalanche processes is presented. The Laplace and Poisson equations for the electrostatic potential in the gate oxide and bulk and the current-continuity equations for the electron and hole densities are solved using finite-difference techniques. The current-continuity equations incorporate terms modeling avalanche generation, bulk and surface Shockley-Read-Hall thermal generation-recombination, and Auger recombination processes. The simulation is performed to a depth in the substrate sufficient to include the depletion region, and the remaining substrate is modeled as a parasitic resistance. The increase in the substrate potential caused by the substrate current flowing through the substrate resistance is also included. The hot-electon distribution function is modeled using Baraff's maximum anisotropy distribution function. The model is used to study hot-electron phenomena including negative-resistance avalanche breakdown in short-channel MOSFET's and electron injection into the gate oxide. The model accurately predicts the positive-resistance branch of the drain current-voltage characteristic and could, in principle, predict the negative-resistance branch and the sustain voltage.

Watanabe, D.S.; Slamet, S.

1983-09-01

363

H? Absorption by Hot Jupiter Atmospheres  

NASA Astrophysics Data System (ADS)

While the investigation of the hydrogen content of Hot Jupiter outflows is primarily done through observed Lyman-? absorption during transit. The observation by Jensen et al. of H? absorption by the atmospheres of HD189733b and HD209458b offers a complementary probe of the hydrogen content of hot Jupiter atmospheres. Motivated by this observation, we have developed a model of a hydrostatic atmosphere in thermal and photoionization equilibrium in order to better understand the HD189733b detection. The n=2 level population is calculated by balancing collisional and radiative processes. The H? absorption signal is primarily due to metastable 2s hydrogen found in the neutral atomic layer where its abundance varies slowly with radius despite the total hydrogen abundance decreasing exponentially. The 2s hydrogen is primarily formed through collisional excitation from the ground state and is subsequently destroyed by collisional transitions to the 2p state followed by rapid radiative de-excitation With an enhanced ionization rate, the model can approximately reproduce the HD189733b H? transit depths.

Christie, Duncan; Arras, Phil; Li, Zhi-Yun

2014-11-01

364

HOT DEBRIS DUST AROUND HD 106797  

SciTech Connect

Photometry of the A0 V main-sequence star HD 106797 with AKARI and Gemini/T-ReCS is used to detect excess emission over the expected stellar photospheric emission between 10 and 20 {mu}m, which is best attributed to hot circumstellar debris dust surrounding the star. The temperature of the debris dust is derived as T {sub d} {approx} 190 K by assuming that the excess emission is approximated by a single temperature blackbody. The derived temperature suggests that the inner radius of the debris disk is {approx}14 AU. The fractional luminosity of the debris disk is 1000 times brighter than that of our own zodiacal cloud. The existence of such a large amount of hot dust around HD 106797 cannot be accounted for by a simple model of the steady state evolution of a debris disk due to collisions, and it is likely that transient events play a significant role. Our data also show a narrow spectral feature between 11 and 12 {mu}m attributable to crystalline silicates, suggesting that dust heating has occurred during the formation and evolution of the debris disk of HD 106797.

Fujiwara, Hideaki; Onaka, Takashi [Department of Astronomy, School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Yamashita, Takuya [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Ishihara, Daisuke; Kataza, Hirokazu; Ootsubo, Takafumi; Murakami, Hiroshi; Nakagawa, Takao; Hirao, Takanori; Enya, Keigo [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan); Fukagawa, Misato [Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka (Japan); Marshall, Jonathan P.; White, Glenn J. [Department of Physics and Astronomy, The Open University, Walton Hall, Milton Keynes, MK7 6AA (United Kingdom)], E-mail: fujiwara@astron.s.u-tokyo.ac.jp

2009-04-10

365

Small Hot Jet Acoustic Rig Validation  

NASA Technical Reports Server (NTRS)

The Small Hot Jet Acoustic Rig (SHJAR), located in the Aeroacoustic Propulsion Laboratory (AAPL) at the NASA Glenn Research Center in Cleveland, Ohio, was commissioned in 2001 to test jet noise reduction concepts at low technology readiness levels (TRL 1-3) and develop advanced measurement techniques. The first series of tests on the SHJAR were designed to prove its capabilities and establish the quality of the jet noise data produced. Towards this goal, a methodology was employed dividing all noise sources into three categories: background noise, jet noise, and rig noise. Background noise was directly measured. Jet noise and rig noise were separated by using the distance and velocity scaling properties of jet noise. Effectively, any noise source that did not follow these rules of jet noise was labeled as rig noise. This method led to the identification of a high frequency noise source related to the Reynolds number. Experiments using boundary layer treatment and hot wire probes documented this noise source and its removal, allowing clean testing of low Reynolds number jets. Other tests performed characterized the amplitude and frequency of the valve noise, confirmed the location of the acoustic far field, and documented the background noise levels under several conditions. Finally, a full set of baseline data was acquired. This paper contains the methodology and test results used to verify the quality of the SHJAR rig.

Brown, Cliff; Bridges, James

2006-01-01

366

Hot Cell Window Shielding Analysis Using MCNP  

SciTech Connect

The Idaho National Laboratory Materials and Fuels Complex nuclear facilities are undergoing a documented safety analysis upgrade. In conjunction with the upgrade effort, shielding analysis of the Fuel Conditioning Facility (FCF) hot cell windows has been conducted. This paper describes the shielding analysis methodology. Each 4-ft thick window uses nine glass slabs, an oil film between the slabs, numerous steel plates, and packed lead wool. Operations in the hot cell center on used nuclear fuel (UNF) processing. Prior to the shielding analysis, shield testing with a gamma ray source was conducted, and the windows were found to be very effective gamma shields. Despite these results, because the glass contained significant amounts of lead and little neutron absorbing material, some doubt lingered regarding the effectiveness of the windows in neutron shielding situations, such as during an accidental criticality. MCNP was selected as an analysis tool because it could model complicated geometry, and it could track gamma and neutron radiation. A bounding criticality source was developed based on the composition of the UNF. Additionally, a bounding gamma source was developed based on the fission product content of the UNF. Modeling the windows required field inspections and detailed examination of drawings and material specifications. Consistent with the shield testing results, MCNP results demonstrated that the shielding was very effective with respect to gamma radiation, and in addition, the analysis demonstrated that the shielding was also very effective during an accidental criticality.

Chad L. Pope; Wade W. Scates; J. Todd Taylor

2009-05-01

367

Hot water can freeze faster than cold?!?  

E-print Network

We review the Mpemba effect, where intially hot water freezes faster than initially cold water. While the effect appears impossible at first sight, it has been seen in numerous experiments, was reported on by Aristotle, Francis Bacon, and Descartes, and has been well-known as folklore around the world. It has a rich and fascinating history, which culminates in the dramatic story of the secondary school student, Erasto Mpemba, who reintroduced the effect to the twentieth century scientific community. The phenomenon, while simple to describe, is deceptively complex, and illustrates numerous important issues about the scientific method: the role of skepticism in scientific inquiry, the influence of theory on experiment and observation, the need for precision in the statement of a scientific hypothesis, and the nature of falsifiability. We survey proposed theoretical mechanisms for the Mpemba effect, and the results of modern experiments on the phenomenon. Studies of the observation that hot water pipes are more likely to burst than cold water pipes are also described.

Monwhea Jeng

2005-12-29

368

Atmospheres of Hot Super-Earths  

NASA Astrophysics Data System (ADS)

Hot super-Earths likely possess minimal atmospheres established through vapor saturation equilibrium with the ground. We solve the hydrodynamics of these tenuous atmospheres at the surface of CoRot-7b, Kepler-10b, and 55 Cnc-e, including idealized treatments of magnetic drag and ohmic dissipation. We find that atmospheric pressures remain close to their local saturation values in all cases. Despite the emergence of strongly supersonic winds which carry sublimating mass away from the substellar point, the atmospheres do not extend much beyond the day-night terminators. Ground temperatures, which determine the planetary thermal (infrared) signature, are largely unaffected by exchanges with the atmosphere and thus follow the effective irradiation pattern. Atmospheric temperatures, however, which control cloud condensation and thus albedo properties, can deviate substantially from the irradiation pattern. Magnetic drag and ohmic dissipation can also strongly impact the atmospheric behavior, depending on atmospheric composition and the planetary magnetic field strength. We conclude that hot super-Earths could exhibit interesting signatures in reflection (and possibly in emission) which would trace a combination of their ground, atmospheric, and magnetic properties.

Castan, Thibaut; Menou, Kristen

2011-12-01

369

Hot Jupiters in binary star systems  

E-print Network

Radial velocity surveys find Jupiter mass planets with semi-major axes a less than 0.1 AU around ~1% of solar-type stars; counting planets with $a$ as large as 5 AU, the fraction of stars having planets reaches ~ 10% {Marcy,Butler}. An examination of the distribution of semi-major axes shows that there is a clear excess of planets with orbital periods around 3 or 4 days, corresponding to a~0.03$ AU, with a sharp cutoff at shorter periods (see Figure 1). It is believed that Jupiter mass planets form at large distances from their parent stars; some fraction then migrate in to produce the short period objects. We argue that a significant fraction of the `hot Jupiters' (aJupiters with the peak of the semimajor axis distribution lying around 3 days. For the observed distributions of binary separation, eccentricity and mass ratio, roughly 2.5% of planets with initial semimajor axis a_p ~ 5au will migrate to within 0.1au of their parent star. Kozai migration could account for 10% or more of the observed hot Jupiters.

Yanqin Wu; Norman W. Murray; J. Michael Ramsahai

2007-08-02

370

Characterizing the Hot Kepler Objects of Interest  

NASA Astrophysics Data System (ADS)

Thousands of exoplanets have been discovered to date; most orbit stars that are similar to our Sun (FGK dwarfs) or cooler (M dwarfs). Detecting planets orbiting hotter stars (A dwarfs) is a challenge because hot stars have rotationally-broadened spectral features and large radii. Accumulating a statistical sample of well-characterized planets orbiting A stars is important to constrain trends in planet occurrence and orbital properties as a function of stellar mass. Throughout its four years of operation, the Kepler mission monitored a few thousand hot stars (T_eff > 7000K) with sufficient photometric precision to detect the transits of Jupiter-size planets. We characterize the main sequence A stars with transiting planet candidates detected by Kepler. We identify likely A stars in the Kepler Input Catalog (KIC) by their stellar effective temperatures, derived from KIC grizJHK photometry using the empirical relations from Boyajian et al. (2013). To verify the classification of a subset of these stars, we measure their spectra using Palomar DBSP and collect high-resolution images with Keck NIRC2. We determine the physical parameters of the transiting planets' orbits by fitting the Kepler transit light curves with Markov Chain Monte Carlo methods. By constraining the semi-major axis and eccentricity distributions of planets orbiting A stars, we gain insights into the formation and tidal evolution of planets in a relatively uncharted region of the H-R diagram.

Price, Ellen; Rogers, Leslie; Johnson, John; Shporer, Avi; Morton, Tim; Crepp, Justin R.; Swift, Jonathan; Muirhead, Philip Steven

2015-01-01

371

Hot Dog and Butterfly, Nereidum Montes  

NASA Technical Reports Server (NTRS)

Some of the pictures returned from Mars by the Mars Orbiter Camera (MOC) onboard the Mars Global Surveyor (MGS) spacecraft show features that--at a glance--resemble familiar, non-geological objects on Earth. For example, the picture above at the left shows several low, relatively flat-topped hills (mesas) on the floor of a broad valley among the mountains of the Nereidum Montes region, northeast of Argyre Planitia. One of the mesas seen here looks like half of a butterfly (upper subframe on right). Another hill looks something like a snail or a hot dog wrapped and baked in a croissant roll (lower subframe on right). These mesas were formed by natural processes and are most likely the eroded remnants of a formerly more extensive layer of bedrock. In the frame on the left, illumination is from the upper left and the scene covers an area 2.7 km (1.7 miles) wide by 6.8 km (4.2 miles) high. The 'butterfly' is about 800 meters (875 yards) in length and the 'hot dog' is about 1 km (0.62 miles) long.

Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

1999-01-01

372

ATMOSPHERES OF HOT SUPER-EARTHS  

SciTech Connect

Hot super-Earths likely possess minimal atmospheres established through vapor saturation equilibrium with the ground. We solve the hydrodynamics of these tenuous atmospheres at the surface of CoRot-7b, Kepler-10b, and 55 Cnc-e, including idealized treatments of magnetic drag and ohmic dissipation. We find that atmospheric pressures remain close to their local saturation values in all cases. Despite the emergence of strongly supersonic winds which carry sublimating mass away from the substellar point, the atmospheres do not extend much beyond the day-night terminators. Ground temperatures, which determine the planetary thermal (infrared) signature, are largely unaffected by exchanges with the atmosphere and thus follow the effective irradiation pattern. Atmospheric temperatures, however, which control cloud condensation and thus albedo properties, can deviate substantially from the irradiation pattern. Magnetic drag and ohmic dissipation can also strongly impact the atmospheric behavior, depending on atmospheric composition and the planetary magnetic field strength. We conclude that hot super-Earths could exhibit interesting signatures in reflection (and possibly in emission) which would trace a combination of their ground, atmospheric, and magnetic properties.

Castan, Thibaut [Departement de Physique, Ecole Normale Superieure, 24 rue Lhomond, 75005 Paris (France); Menou, Kristen [Department of Astronomy, Columbia University, 550 West 120th Street, New York, NY 10027 (United States)

2011-12-20

373

Hot spot volcanism in western North America  

NSDL National Science Digital Library

This lab project is in two parts. In the first part students are given a map of Snake River Plain volcanic centers with a range of dates of eruptions. Based on what they know about hot-spot tracks, they use the map and reported isotopic ages to calculate a range of values for the relative velocities of the North American Plate and the Yellowstone hot spot. In the second part, students are given a map of the distribution of a volcanic ash from the Yellowstone volcanic field, with thickness of the ash where known. Students are asked to contour the map to show how the ash is distributed, and think about the factors that affect that thickness, both during and after the eruption. In both parts of the lab students have to deal with real data that is incomplete in some cases, and usually occurs as a range of values. Students must make decisions about how to treat incomplete data sets that do not have absolute values.

Trexler, James

374

Deep drilling technology for hot crystalline rock  

SciTech Connect

The development of Hot Dry Rock (HDR) geothermal systems at the Fenton Hill, New Mexico site has required the drilling of four deep boreholes into hot, Precambrian granitic and metamorphic rocks. Thermal gradient holes, four observation wells 200 m (600 ft) deep, and an exploration core hole 800 m (2400 ft) deep guided the siting of the four deep boreholes. Results derived from the exploration core hole, GT-1 (Granite Test No. 1), were especially important in providing core from the granitic rock, and establishing the conductive thermal gradient and heat flow for the granitic basement rocks. Essential stratigraphic data and lost drilling-fluid zones were identified for the volcanic and sedimentary rocks above the contact with the crystalline basement. Using this information drilling strategies and well designs were then devised for the planning of the deeper wells. The four deep wells were drilled in pairs, the shallowest were planned and drilled to depths of 3 km in 1975 at a bottom-hole temperature of nearly 200/sup 0/C. These boreholes were followed by a pair of wells, completed in 1981, the deepest of which penetrated the Precambrian basement to a vertical depth of 4.39 km at a temperature of 320/sup 0/C.

Rowley, J.C.

1984-01-01

375

Magnetic spots on hot massive stars  

NASA Astrophysics Data System (ADS)

Context. Hot luminous stars show a variety of phenomena in their photospheres and winds which still lack clear physical explanation. Among these phenomena are photospheric turbulence, line profile variability (LPV), non-thermal emission, non-radial pulsations, discrete absorption components (DACs) and wind clumping. It has been argued that a convection zone close to the stellar surface could be responsible for some of these phenomena. This convective zone is caused by a peak in the opacity associated with iron-group elements and is referred to as the "iron convection zone" (FeCZ). Aims: Assuming dynamo action producing magnetic fields at equipartition in the FeCZ, we investigate the occurrence of subsurface magnetism in OB stars. Then we study the surface emergence of these magnetic fields and discuss possible observational signatures of magnetic spots. Methods: Simple estimates are made using the subsurface properties of massive stars, as calculated in 1D stellar evolution models. Results: We find that magnetic fields of sufficient amplitude to affect the wind could emerge at the surface via magnetic buoyancy. While at this stage it is difficult to predict the geometry of these features, we show that magnetic spots of size comparable to the local pressure scale height can manifest themselves as hot, bright spots. Conclusions: Localized magnetic fields could be widespread in those early type stars that have subsurface convection. This type of surface magnetism could be responsible for photometric variability and play a role in X-ray emission and wind clumping.

Cantiello, M.; Braithwaite, J.

2011-10-01

376

METC CFD simulations of hot gas filtration  

SciTech Connect

Computational Fluid Dynamic (CFD) simulations of the fluid/particle flow in several hot gas filtration vessels will be presented. These simulations have been useful in designing filtration vessels and in diagnosing problems with filter operation. The simulations were performed using the commercial code FLUENT and the METC-developed code MFIX. Simulations of the initial configuration of the Karhula facility indicated that the dirty gas flow over the filter assemblage was very non-uniform. The force of the dirty gas inlet flow was inducing a large circulation pattern that caused flow around the candles to be in opposite directions on opposite sides of the vessel. By introducing a system of baffles, a more uniform flow pattern was developed. This modification may have contributed to the success of the project. Several simulations of configurations proposed by Industrial Filter and Pump were performed, varying the position of the inlet. A detailed resolution of the geometry of the candles allowed determination of the flow between the individual candles. Recent simulations in support of the METC/CeraMem Cooperative Research and Development Agreement have analyzed the flow in the vessel during the cleaning back-pulse. Visualization of experiments at the CeraMem cold-flow facility provided confidence in the use of CFD. Extensive simulations were then performed to assist in the design of the hot test facility being built by Ahlstrom/Pyropower. These tests are intended to demonstrate the CeraMem technology.

O`Brien, T.J.

1995-06-01

377

THz Hot-Electron Photon Counter  

NASA Technical Reports Server (NTRS)

We present a concept for the hot-electron transition-edge sensor capable of counting THz photons. The main need for such a sensor is a spectroscopy on future space telescopes where a background limited NEP approx. 10(exp -20) W/H(exp 1/2) is expected at around 1 THz. Under these conditions, the rate of photon arrival is very low and any currently imaginable detector with sufficient sensitivity will operate in the photon counting mode. The Hot-Electron Photon Counter based on a submicron-size Ti bridge has a very low heat capacity which provides a high enough energy resolution (approx.140 GHz) at 0.3 K. With the sensor time constant of a few microseconds, the dynamic range would be approx. 30 dB. The sensor couples to radiation via a planar antenna and is read by a SQUID amplifier or by a 1-bit RSFQ ADC. A compact array of the antenna-coupled counters can be fabricated on a silicon wafer without membranes.

Karasik, Boris S.; Sergeev, Andrei V.

2004-01-01

378

Two new extremely hot pulsating white dwarfs  

NASA Technical Reports Server (NTRS)

High speed photometry of the extremely hot, nearly degenerate stars PG 1707 + 427 and PG 2131 + 066 reveals that they are low-amplitude pulsating variables. Power spectral analysis shows both to be multiperiodic, with dominant periods of 7.5 and 6.4-6.9 minutes, respectively. Together with the known pulsators PG 1159 - 035 and the central star of the planetary nebula Kohoutek 1-16, these objects define a new pulsational instability strip at the hot edge of the H-R diagram. The variations of these objects closely resemble those of the much cooler pulsating ZZ Ceti DA white dwarfs; both groups are probably nonradial g-mode pulsators. Evolutionary contraction of the PG 1159 - 035 variables may lead to period changes that would be detectable in as little as 1 year. The optical and IUE spectra of the PG 1159 - 035 variables are characterized by absorption lines of C IV and other CNO ions, indicating radiative levitation of species heavier than helium. He II is also present in the spectra, but the hydrogen Balmer lines are absent. Effective temperatures near 100,000 K are required, and the He II 4686 A profiles indicate log g greater than 6. These helium-rich pulsators form the hottest known subgroup of the DO white dwarfs.

Bond, H. E.; Grauer, A. D.; Green, R. F.; Liebert, J. W.

1984-01-01

379

Water Temperature From Hot Water Outlets in a Major Public Hospital: How Hot is Our Water?  

PubMed Central

Objectives: To measure the water temperature issuing from a representative sample of patient-accessible outlets around the Royal Adelaide Hospital. To initiate an audit cycle in the event of unacceptably high water temperatures to ensure their reduction. Methods: Samples were taken of water issuing from hot taps, showers, and hand hygiene basins in patient areas throughout the hospital, encompassing newly renovated as well as old sections of the hospital. A 45 second warming period was followed by hot water collection into a polystyrene cup to 8 cm. The mean of 3 temperatures measured using an infrared thermometer was calculated. Results: Several taps and patient showers were demonstrated to supply water at a temperature capable of causing scald injuries. Most problem outlets were found in the oldest section of the hospital, fewer in the wing of intermediate age and none in the most recently renovated emergency block. The data were tabulated and summarized before being passed on to RAH Engineering and Building Services, which initiated remedial action. Several thermostatic mixing valves were found to be faulty (and replaced) or poorly set (and re-set). After this adjustment, outlets previously supplying excessively hot water were re-tested and found to be safe, closing the audit loop. Conclusion: Maintenance services infrequently conduct scheduled assessment of hot water outlet temperatures and rely on staff member complaints or concerns to focus their attention on problem areas. With recent evidence of the disastrous potential of hot water on a vulnerable population of hospital in-patients, hazard identification and reporting is everybody's responsibility. PMID:22184507

Hartley, Dana; McCarthy, Ashlee; Greenwood, John E.

2011-01-01

380

Geothermal Exploration in Hot Springs, Montana  

SciTech Connect

The project involves drilling deeper in the Camp Aqua well dri lled in June 1982 as part of an effort to develop an ethanol plant. The purpose of the current drill ing effort is to determine if water at or above 165???????????????????????????????°F exists for the use in low temperature resource power generation. Previous geothermal resource study efforts in and around Hot Springs , MT and the Camp Aqua area (NE of Hot Springs) have been conducted through the years. A confined gravel aquifer exists in deep alluvium overlain by approximately 250???????????????¢???????????????????????????????? of si lt and c lay deposits from Glacial Lake Missoula. This gravel aquifer overlies a deeper bedrock aquifer. In the Camp Aqua area several wel l s exist in the gravel aquifer which receives hot water f rom bedrock fractures beneath the area. Prior to this exploration, one known well in the Camp Aqua area penetrated into the bedrock without success in intersecting fractures transporting hot geothermal water. The exploration associated with this project adds to the physical knowledge database of the Camp Aqua area. The dri l l ing effort provides additional subsurface information that can be used to gain a better understanding of the bedrock formation that i s leaking hot geothermal water into an otherwise cold water aquifer. The exi s t ing well used for the explorat ion is located within the ???????????????¢????????????????????????????????center???????????????¢??????????????????????????????? of the hottest water within the gravel aquifer. This lent i t sel f as a logical and economical location to continue the exploration within the existing well. Faced with budget constraints due to unanticipated costs, changing dril l ing techniques stretched the limited project resources to maximize the overa l l well depth which f e l l short of original project goals. The project goal of finding 165???????????????????????????????°F or hotter water was not achieved; however the project provides additional information and understanding of the Camp Aqua area that could prove valuable in future exploration efforts

Toby McIntosh, Jackola Engineering

2012-09-26

381

Plasmon-induced hot carriers in metallic nanoparticles.  

PubMed

Plasmon-induced hot carrier formation is attracting an increasing research interest due to its potential for applications in photocatalysis, photodetection and solar energy harvesting. However, despite very significant experimental effort, a comprehensive theoretical description of the hot carrier generation process is still missing. In this work we develop a theoretical model for the plasmon-induced hot carrier process and apply it to spherical silver nanoparticles and nanoshells. In this model, the conduction electrons of the metal are described as free particles in a finite spherical potential well, and the plasmon-induced hot carrier production is calculated using Fermis golden rule. We show that the inclusion of many-body interactions has only a minor influence on the results. Using the model we calculate the rate of hot carrier generation, finding that it closely follows the spectral profile of the plasmon. Our analysis reveals that particle size and hot carrier lifetime play a central role in determining both the production rate and the energy distribution of the hot carriers. Specifically, larger nanoparticle sizes and shorter lifetimes result in higher carrier production rates but smaller energies, and vice versa. We characterize the efficiency of the hot carrier generation process by introducing a figure of merit that measures the number of high energy carriers generated per plasmon. Furthermore, we analyze the spatial distribution and directionality of these excitations. The results presented here contribute to the basic understanding of plasmon-induced hot carrier generation and provide insight for optimization of the process. PMID:24960573

Manjavacas, Alejandro; Liu, Jun G; Kulkarni, Vikram; Nordlander, Peter

2014-08-26

382

Diving company claims record in gulf hot tap  

SciTech Connect

This paper reports that the deepest pipeline hot tap in the U.S. Gulf of Mexico, and possibly the world, was recently accomplished in 630 ft of seawater, according to Offshore Petroleum Divers Inc. (OPD) which carried out the dive. The hot tap, in South Pass Block 50,. connected a newly constructed BP Exploration 8-in. pipeline to an operational 10-in. oil pipeline for Chevron Pipeline Co. Hot taps enable operators to attach an ancillary pipeline to an operational or hot pipeline. The procedure avoids construction of additional pipelines to a production platform.

Not Available

1992-03-16

383

Photovoltaic module hot spot durability design and test methods  

NASA Technical Reports Server (NTRS)

As part of the Jet Propulsion Laboratory's Low-Cost Solar Array Project, the susceptibility of fat-plate modules to hot-spot problems is investigated. Hot-spot problems arise in modules when the cells become back-biased and operate in the negative-voltage quadrant, as a result of short-circuit current mismatch, cell cracking or shadowing. The details of a qualification test for determining the capability of modules of surviving field hot-spot problems and typical results of this test are presented. In addition, recommended circuit-design techniques for improving the module and array reliability with respect to hot-spot problems are presented.

Arnett, J. C.; Gonzalez, C. C.

1981-01-01

384

Information Presentations Projects Links Policies CS 591: Hot Topics  

E-print Network

Information Presentations Projects Links Policies CS 591: Hot Topics in Cybersecurity Department Presentations: 40%, Cybersecurity Project: 30%, Final Exam: 20%, and Participation: 10%. Reference Books: Cybersecurity Project Prese

Nickrent, Daniel L.

385

Getting into hot water Problematizing hot water service demand: The case of Old Cairo  

NASA Astrophysics Data System (ADS)

This dissertation analyzes hot water demand and service infrastructure in two neighboring but culturally distinct communities of the urban poor in the inner-city area of central Cairo. The communities are the Historic Islamic Cairo neighborhood of Darb Al Ahmar at the foot of Al-Azhar park, and the Zurayib neighborhood of Manshiyat Nasser where the Coptic Zabaleen Recyclers live. The study focuses on the demand side of the hot water issue and involves consideration of built-environment infrastructures providing piped water, electricity, bottled gas, sewage, and the support structures (wiring and plumbing) for consumer durables (appliances such as hot water heaters, stoves, refrigerators, air conditioners) as well as water pumps and water storage tanks. The study asks the questions "How do poor communities in Cairo value hot water" and "How do cost, infrastructure and cultural preferences affect which attributes of hot water service are most highly preferred?". To answer these questions household surveys based primarily on the World Bank LSMS modules were administered by professional survey teams from Darb Al Ahmar's Aga Khan Trust for Culture and the Zabaleen's local NGO "Spirit of Youth" in their adjacent conununities in and surrounding historic Cairo. In total 463 valid surveys were collected, (231 from Darb Al Ahmar, 232 from the Zabaleen). The surveys included a contingent valuation question to explore Willingness to Pay for improved hot water service; the surveys queried household assets as proxies for income. The dissertation's findings reveal that one quarter of the residents of Darb Al Ahmar and two-thirds of the residents of Manshiyet Nasser's Zabaleen lack conventional water heating service. Instead they employ various types of stoves and self-built contraptions to heat water, usually incurring considerable risk and opportunity costs. However the thesis explores the notion that this is rational "satisficing" behavior; despite the shortcomings of such self-help strategies, the greater flexibility they provide may lead to superior long-term outcomes in a time of uncertain and rising energy and commodities prices and an increasing availability of new, less expensive, increasingly modular, and more efficient technologies that are easier for individual households to install and use, especially if the State or non-governmental institutions can provide implementation support. The descriptive statistics and the multivariate models obtained through the analysis of the data gathered in the surveys show that while purchase price and running costs for dedicated water heating systems are considerations for families desiring hot water, the infrastructural demands of modern appliances vis a vis a consumer's given built environment and the historical/cultural legacy of the consumer's past hot water choices and practices are often more important determinants of the kind of water heating used and desired today. Our study shows, for example, that while higher income is associated with owning a water heater in a simple model with few explanatory variables (Model 3) it's significance disappears when controlling for Ethnicity and infrastructural elements (Model 1). This might suggest that while within communities there is a point at which making more money implies a shift to consumer "modernity", overall the availability of more money in these neighborhoods as a whole doesn't guarantee that the utility promised by modern appliances will be realized. A similar point can be made about formal education levels, which appear insignificant in our models. Policy that aimed merely at sending more kids to school would not address the great deficiencies that many Egyptian schools are noted for. There is no guarantee that merely expanding Egypt's "universal education" policy to include children who have fallen through the cracks would help increase consumer awareness or consumer choice. On the other hand both water availability and presence of hot water pipes, as proxies for assets in

Culhane, Thomas Henry

386

AIM cryocooler developments for HOT detectors  

NASA Astrophysics Data System (ADS)

Significantly increased FPA temperatures for both Mid Wave and Long Wave IR detectors, i.e. HOT detectors, which have been developed in recent years are now leaving the development phase and are entering real application. HOT detectors allowing to push size weight and power (SWaP) of Integrated Detectors Cooler Assemblies (IDCA's) to a new level. Key component mainly driving achievable weight, volume and power consumption is the cryocooler. AIM cryocooler developments are focused on compact, lightweight linear cryocoolers driven by compact and high efficient digital cooler drive electronics (DCE) to also achieve highest MTTF targets. This technology is using moving magnet driving mechanisms and dual or single piston compressors. Whereas SX030 which was presented at SPIE in 2012 consuming less 3 WDC to operate a typical IDCA at 140K, next smaller cooler SX020 is designed to provide sufficient cooling power at detector temperature above 160K. The cooler weight of less than 200g and a total compressor length of 60mm makes it an ideal solution for all applications with limited weight and power budget, like in handheld applications. For operating a typical 640x512, 15?m MW IR detector the power consumption will be less than 1.5WDC. MTTF for the cooler will be in excess of 30,000h and thus achieving low maintenance cost also in 24/7 applications. The SX020 compressor is based on a single piston design with integrated passive balancer in a new design achieves very low exported vibration in the order of 100mN in the compressor axis. AIM is using a modular approach, allowing the chose between 5 different compressor types for one common Stirling expander. The 6mm expander with a total length of 74mm is now available in a new design that fits into standard dewar bores originally designed for rotary coolers. Also available is a 9mm coldfinger in both versions. In development is an ultra-short expander with around 35mm total length to achieve highest compactness. Technical solutions and key performance data for AIM's HOT cryocoolers will be presented.

Rhlich, I.; Mai, M.; Withopf, A.; Rosenhagen, C.

2014-06-01

387

Explosions and hot spots in supertree methods.  

PubMed

In phylogenetic systematics a problem of great practical and theoretical interest is to construct one or more large phylogenies (evolutionary trees), i.e., supertrees, from a given set of small phylogenies with overlapping sets of leaf labels. Although the methods being used to solve this problem are usually given plausible biological or theoretical justifications, occasionally it is possible to see that the result of a supertree method (SM) is explosive, and therefore logically meaningless, in the sense that it has been inferred from logical propositions that are contradictory. This paper presents the basic ideas and issues of how explosions affect the inference of rooted trees by SMs. We define the relevant concepts, give examples, and show how sometimes it is possible to identify hot spots in the input from which an SM may make explosive inferences that cannot be logically justified. PMID:18472112

Day, William H E; McMorris, F R; Wilkinson, Mark

2008-07-21

388

Electrically tunable hot-silicon terahertz attenuator  

NASA Astrophysics Data System (ADS)

We have developed a continuously tunable, broadband terahertz attenuator with a transmission tuning range greater than 103. Attenuation tuning is achieved electrically, by simply changing the DC voltage applied to a heating wire attached to a bulk silicon wafer, which controls its temperature between room temperature and 550 K, with the corresponding free-carrier density adjusted between 1011 cm-3 and 1017 cm-3. This "hot-silicon"-based terahertz attenuator works most effectively at 450-550 K (corresponding to a DC voltage variation of only 7 V) and completely shields terahertz radiation above 550 K in a frequency range of 0.1-2.5 THz. Both intrinsic and doped silicon wafers were tested and demonstrated to work well as a continuously tunable attenuator. All behaviors can be understood quantitatively via the free-carrier Drude model taking into account thermally activated intrinsic carriers.

Wang, Minjie; Vajtai, Robert; Ajayan, Pulickel M.; Kono, Junichiro

2014-10-01

389

Cambridge Cosmology: The Hot Big Bang Model  

NSDL National Science Digital Library

This website introduces the Big Bang Model (also known as the standard cosmology) and the fact that it successfully explains many details about the formation of the Universe. It also touches upon issues not explainable through standard cosmology. A brief history of observational cosmology in the 20th century is given as a reference, followed by a brief history of our Universe as told through standard cosmology as well as particle and quantum cosmology. This site goes through the four 'pillars' of the Hot Big Bang Model: expansion of the Universe after a violent explosion, origin of the cosmic background radiation, nucleosynthesis of the light elements, and the formation of galaxies and large-scale structures in the Universe.

Shellard, Paul

390

Thermodynamics of pairing transition in hot nuclei  

E-print Network

The pairing correlations in hot nuclei $^{162}$Dy are investigated in terms of the thermodynamical properties by covariant density functional theory. The heat capacities $C_V$ are evaluated in the canonical ensemble theory and the paring correlations are treated by a shell-model-like approach, in which the particle number is conserved exactly. A S-shaped heat capacity curve, which agrees qualitatively with the experimental data, has been obtained and analyzed in details. It is found that the one-pair-broken states play crucial roles in the appearance of the S shape of the heat capacity curve. Moreover, due to the effect of the particle-number conservation, the pairing gap varies smoothly with the temperature, which indicates a gradual transition from the superfluid to the normal state.

Lang Liu; Zhen-Hua Zhang; Peng-Wei Zhao

2014-12-16

391

STOVL hot gas ingestion control technology  

SciTech Connect

This paper reports on a comprehensive wind tunnel test program conducted to evaluate control of Hot Gas Ingestion (HGI) on a 9.2 percent scale model of the McDonnell Aircraft Company model 279-3C advanced Short Takeoff and Vertical Landing (STOVL) configuration. The test was conducted in the NASA-Lewis Research Center 9 ft by 15 ft Low Speed Wind Tunnel during the summer of 1987. Initial tests defined baseline HGI levels as determined by engine face temperature rise and temperature distortion. Subsequent testing was conducted to evaluate HGI control parametrically using Lift Improvement Devices (LIDs), forward nozzle splay angle, a combination of LIDs and forward nozzle splay angle, and main inlet blocking. The results from this test program demonstrate that HGI can be effectively controlled and that HGI is not a barrier to STOVL aircraft development.

Amuedo, K.C.; Williams, B.R.; Flood, J.D. (McDonnell Aircraft Co., McDonnell Douglas Corp., St. Louis, MO (US)); Johns, A.L. (NASA Lewis Research Center, Cleveland, OH (US))

1991-01-01

392

Radiative transfer in a hot plasma  

NASA Astrophysics Data System (ADS)

The radiative heat flux in a hot (1 Mev), optically thick plasma (i.e. one where departure from equilibrium owing to a temperature gradient is small) depends on the opacity of the medium, the Rosseland mean opacity which is defined by an appropriate averaging of the photon mean path l(omega) over frequency. Small departures from equilibrium give rise to a photon momentum distribution which is assumed to be the Planck function corrected by a small quantity which depends on l(omega) (diffusion approximation) and positrons and electrons are assumed in thermal balance. It is then possible to linearize the relativistic Boltzmann transport equation for the photons, which yields a linear integral equation for l(omega). The relativistic Boltzmann transport equation for the photons involves microscopic processes of interactions for the radiation. For T around 1 Mev, two dominant processes have to be considered, Compton scattering and annihilation-creation of pairs.

Goupil, M. J.

1984-10-01

393

Telescopic nanotube device for hot nanolithography  

DOEpatents

A device for maintaining a constant tip-surface distance for producing nanolithography patterns on a surface using a telescopic nanotube for hot nanolithography. An outer nanotube is attached to an AFM cantilever opposite a support end. An inner nanotube is telescopically disposed within the outer nanotube. The tip of the inner nanotube is heated to a sufficiently high temperature and brought in the vicinity of the surface. Heat is transmitted to the surface for thermal imprinting. Because the inner tube moves telescopically along the outer nanotube axis, a tip-surface distance is maintained constant due to the vdW force interaction, which in turn eliminates the need of an active feedback loop.

Popescu, Adrian; Woods, Lilia M

2014-12-30

394

HotSpotter? Neutron/Gamma Detector  

SciTech Connect

The HotSpotter{trademark} Neutron/Gamma Detector combines in a single detecting module high sensitivity to gamma rays up to 3 MeV and sensitivity to neutrons. Using a 15 mm cubic CdWO{sub 4} (cadmium tungstate) crystal mounted on a 25 mm photomultiplier, the instrument realizes a factor of 5 increased photopeak efficiency over NaI(Tl) at 1 MeV, and a factor of 2 improvement over CsI(Tl). The addition of a 0.5 mm layer of {sup 10}B- impregnated epoxy covering the crystal provides neutron sensitivity without sacrificing gamma ray spectroscopic characteristics. Neutrons are detected by the presence of the 478 keV gamma from the {sup 10}B(n,{alpha}){sup 7}Li* reaction. In this paper, we describe the electronics and software of the instrument, and some of its characteristics.

Bell, Z.W.

2003-04-01

395

Legionella Infection Risk from Domestic Hot Water  

PubMed Central

We investigated Legionella and Pseudomonas contamination of hot water in a cross-sectional multicentric survey in Italy. Chemical parameters (hardness, free chlorine, and trace elements) were determined. Legionella spp. were detected in 33 (22.6%) and Pseudomonas spp. in 56 (38.4%) of 146 samples. Some factors associated with Legionella contamination were heater type, tank distance and capacity, water plant age, and mineral content. Pseudomonas presence was influenced by water source, hardness, free chlorine, and temperature. Legionella contamination was associated with a centralized heater, distance from the heater point >10 m, and a water plant >10 years old. Furthermore, zinc levels of <20 ?g/L and copper levels of >50 ?g/L appeared to be protective against Legionella colonization. Legionella species and serogroups were differently distributed according to heater type, water temperature, and free chlorine, suggesting that Legionella strains may have a different sensibility and resistance to environmental factors and different ecologic niches. PMID:15109413

Montagna, M. Teresa; Romano-Spica, Vincenzo; Stampi, Serena; Stancanelli, Giovanna; Triassi, Maria; Neglia, Rachele; Marchesi, Isabella; Fantuzzi, Guglielmina; Tat, Daniela; Napoli, Christian; Quaranta, Gianluigi; Laurenti, Patrizia; Leoni, Erica; De Luca, Giovanna; Ossi, Cristina; Moro, Matteo; DAlcal, Gabriella Ribera

2004-01-01

396

Superconducting cuprate heterostructures for hot electron bolometers  

SciTech Connect

Transport properties of the resistive state of quasi-two dimensional superconducting heterostructures containing ultrathin La{sub 2?x}Sr{sub x}CuO{sub 4} layers synthesized using molecular beam epitaxy are studied. The electron transport exhibits strong deviation from Ohm's law, ?V??I{sup 3}, with a coefficient ?(T) that correlates with the temperature variation of the resistivity d?/dT. Close to the normal state, analysis of the nonlinear behavior in terms of electron heating yields an electron-phonon thermal conductance per unit area g{sub e?ph}?1 W/K cm{sup 2} at T = 20 K, one-two orders of magnitude smaller than in typical superconductors. This makes superconducting LaSrCuO heterostructures to be attractive candidate for the next generation of hot electron bolometers with greatly improved sensitivity.

Wen, B.; Yakobov, R.; Vitkalov, S. A. [Department of Physics, City College of New York, New York 10031 (United States)] [Department of Physics, City College of New York, New York 10031 (United States); Sergeev, A. [SUNY Research Foundation, SUNY at Buffalo, Buffalo, New York 14226 (United States)] [SUNY Research Foundation, SUNY at Buffalo, Buffalo, New York 14226 (United States)

2013-11-25

397

Hot gas accretion in cluster outskirts  

NASA Astrophysics Data System (ADS)

The baryonic content of galaxy clusters grows through the accretion of hot gas over cosmic time. Still at the present epoch accretion processes should be important in the outer regions of clusters, rendering the distribution of X-ray emission clumpy and asymmetric. We present a method based on the azimuthal median to estimate the gas clumping factor and recover unbiased density profiles. We apply this method to a sample of 31 clusters observed with ROSAT/PSPC, and compare with the expectations of hydrodynamical simulations. We also present the results of an XMM mosaic program of the clusters A2142 and Hydra A, in which we discovered accreting substructures around the cluster's virial radius. In particular, we report the XMM discovery of a spectacular X-ray tail in A2142, which we use to set constraints on thermal conduction in the ICM.

Eckert, D.

2014-07-01

398

Hot gas path component cooling system  

DOEpatents

A cooling system for a hot gas path component is disclosed. The cooling system may include a component layer and a cover layer. The component layer may include a first inner surface and a second outer surface. The second outer surface may define a plurality of channels. The component layer may further define a plurality of passages extending generally between the first inner surface and the second outer surface. Each of the plurality of channels may be fluidly connected to at least one of the plurality of passages. The cover layer may be situated adjacent the second outer surface of the component layer. The plurality of passages may be configured to flow a cooling medium to the plurality of channels and provide impingement cooling to the cover layer. The plurality of channels may be configured to flow cooling medium therethrough, cooling the cover layer.

Lacy, Benjamin Paul; Bunker, Ronald Scott; Itzel, Gary Michael

2014-02-18

399

Hot Springs-Garrison Fiber Optic Project  

SciTech Connect

Bonneville Power Administration (BPA) is proposing to upgrade its operational telecommunications system between the Hot Springs Substation and the Garrison Substation using a fiber optic system. The project would primarily involve installing 190 kilometers (120 miles) of fiber optic cable on existing transmission structures and installing new fiber optic equipment in BPA`s substation yards and control houses. BPA prepared an environmental assessment (EA) evaluating the proposed action. This EA was published in October 1994. The EA identifies a number of minor impacts that might occur as a result of the proposed action, as well as some recommended mitigation measures. This Mitigation Action Plan (MAP) identifies specific measures to avoid, minimize, or compensate for impacts identified in the EA.

Not Available

1994-10-01

400

Prototype solar heating and hot water systems  

NASA Technical Reports Server (NTRS)

Alternative approaches to solar heating and hot water system configurations were studied, parametrizing the number and location of the dampers, the number and location of the fans, the interface locations with the furnace, the size and type of subsystems, and operating modes. A two-pass air-heating collector was selected based on efficiency and ease of installation. Also, an energy transport module was designed to compactly contain all the mechanical and electrical control components. System performance calculations were carried out over a heating season for the tentative site location at Tunkhnana, Pa. Results illustrate the effect of collector size, storage capacity, and use of a reflector. Factors which affected system performance include site location, insulative quality of the house, and of the system components. A preliminary system performance specification is given.

1977-01-01

401

Liquid Hot Water Pretreatment of Cellulosic Biomass  

NASA Astrophysics Data System (ADS)

Lignocellulosic biomass is an abundant and renewable resource for fuel ethanol production. However, the lignocellulose is recalcitrant to enzymatic hydrolysis because of its structural complexity. Controlled-pH liquid hot water (LHW) pretreatment of cellulosic feedstock improves its enzymatic digestibility by removing hemicellulose and making the cellulose more accessible to cellulase enzymes. The removed hemicellulose is solubilized in the liquid phase of the pretreated feedstock as oligosaccharides. Formation of monomeric sugars during the LHW pretreatment is minimal. The LHW pretreatment is carried out by cooking the feedstock in process water at temperatures between 160 and 190C and at a pH of 4-7. No additional chemicals are needed. This chapter presents the detailed procedure of the LHW pretreatment of lignocellulosic biomass.

Kim, Youngmi; Hendrickson, Rick; Mosier, Nathan S.; Ladisch, Michael R.

402

MAGNETICALLY CONTROLLED CIRCULATION ON HOT EXTRASOLAR PLANETS  

SciTech Connect

Through the process of thermal ionization, intense stellar irradiation renders hot Jupiter atmospheres electrically conductive. Simultaneously, lateral variability in the irradiation drives the global circulation with peak wind speeds of the order of ?km s{sup 1}. In turn, the interactions between the atmospheric flows and the background magnetic field give rise to Lorentz forces that can act to perturb the flow away from its purely hydrodynamical counterpart. Using analytical theory and numerical simulations, we show here that significant deviations away from axisymmetric circulation are unstable in presence of a non-negligible axisymmetric magnetic field. Specifically, our results suggest that dayside-to-nightside flows, often obtained within the context of three-dimensional circulation models, only exist on objects with anomalously low magnetic fields, while the majority of highly irradiated exoplanetary atmospheres are entirely dominated by zonal jets.

Batygin, Konstantin [Institute for Theory and Computation, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Stanley, Sabine [Department of Physics, University of Toronto, 60 St. George Street, Toronto, ON M5S 1A7 (Canada); Stevenson, David J., E-mail: kbatygin@cfa.harvard.edu [Division of Geological and Planetary Sciences, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States)

2013-10-10

403

Flowfield visualization for SSME hot gas manifold  

NASA Technical Reports Server (NTRS)

The objective of this research, as defined by NASA-Marshall Space Flight Center, was two-fold: (1) to numerically simulate viscous subsonic flow in a proposed elliptical two-duct version of the fuel side Hot Gas Manifold (HGM) for the Space Shuttle Main Engine (SSME), and (2) to provide analytical support for SSME related numerical computational experiments, being performed by the Computational Fluid Dynamics staff in the Aerophysics Division of the Structures and Dynamics Laboratory at NASA-MSFC. Numerical results of HGM were calculations to complement both water flow visualization experiments and air flow visualization experiments and air experiments in two-duct geometries performed at NASA-MSFC and Rocketdyne. In addition, code modification and improvement efforts were to strengthen the CFD capabilities of NASA-MSFC for producing reliable predictions of flow environments within the SSME.

Roger, Robert P.

1988-01-01

404

Extraplanar Hot Gas and Radio Galactic Halos  

NASA Astrophysics Data System (ADS)

We propose ACIS-S observations of two edge-on galaxies, NGC 2683 (Sb) and NGC 7090 (Sc). They are not starburst galaxies, but still show extensive radio halos. With a clean separation of diffuse X-ray emission from discrete sources, we will measure the content, morphology, thermal state, and cooling rate of the hot gas as well as its role in shaping the galactic vertical structures. The results will be compared with our existing work on the two later-type and more active starforming edge-on galaxies, NGC 4631 (Sd) and NGC 3556 (Scd), which also show radio halos. We will examine the the X-ray and radio connection of galactic halos and its dependence on galaxy type, star formation rate, and environment.

Wang, Q. Daniel

2005-09-01

405

Turbine Engine Hot Section Technology (HOST)  

NASA Technical Reports Server (NTRS)

A two-day workshop on the research and plans for turbine engine hot section durability problems was held on October 25 and 26, 1983, at the NASA Lewis Research Center. Presentations were made during six sessions, including structural analysis, fatigue and fracture, surface protective coatings, combustion, turbine heat transfer, and instrumentation, that dealt with the thermal and fluid environment around liners, blades, and vanes, and with material coatings, constitutive behavior, stress-strain response, and life prediction methods for the three components. The principal objective of each session was to disseminate the research results to date, along with future plans, in each of the six areas. Contract and government researchers presented results of their work.

1983-01-01

406

A Hot River Model for TT Hydrae  

NASA Astrophysics Data System (ADS)

TT Hydrae (HD 97528) is an Algol-type interacting binary star system composed of a B9.5 V primary star and a K0 III-IV companion in a 6.95 day orbit. The companion fills its Roche Lobe and is transferring material to the primary star. This material is having a glancing impact upon the primary star. The presence of spectral lines from high temperature ions in the IUE spectra at all orbital phases indicates the accreting material may form a hot river that flows around the equatorial regions of the primary star. Emission lines in spectra taken by HST during totality of primary eclipse may originate in an optically thin disk orbiting the B-type star. The disk needs to be optically thin because some of these spectral lines have no observable absorption counterpart in the IUE spectra.

Orleski, Michael P.

2009-01-01

407

Menopausal hot flashes: mechanisms, endocrinology, treatment.  

PubMed

Hot flashes (HFs) are a rapid and exaggerated heat dissipation response, consisting of profuse sweating, peripheral vasodilation, and feelings of intense, internal heat. They are triggered by small elevations in core body temperature (Tc) acting within a greatly reduced thermoneutral zone, i.e., the Tc region between the upper (sweating) and lower (shivering) thresholds. This is due in part, but not entirely, to estrogen depletion at menopause. Elevated central sympathetic activation, mediated through ?2-adrenergic receptors, is one factor responsible for narrowing of the thermoneutral zone. Procedures which reduce this activation, such as paced respiration and clonidine administration, ameliorate HFs as will peripheral cooling. HFs are responsible for some, but not all, of the sleep disturbance reported during menopause. Recent work calls into question the role of serotonin in HFs. This article is part of a Special Issue entitled 'Menopause'. PMID:24012626

Freedman, Robert R

2014-07-01

408

Hot carriers in a bipolar graphene  

NASA Astrophysics Data System (ADS)

Hot carriers in a doped graphene under dc electric field is described taking into account the intraband energy relaxation due to acoustic phonon scattering and the interband generation-recombination transitions caused by thermal radiation. The consideration is performed for the case when the intercarrier scattering effectively establishes the quasiequilibrium electron-hole distributions, with effective temperature and concentrations of carriers. The concentration and energy balance equations are solved taking into account an interplay between weak energy relaxation and generation-recombination processes. The nonlinear conductivity is calculated for the momentum relaxation caused by the elastic scattering. The current-voltage characteristics, and the transition between bipolar and monopolar regimes of conductivity are obtained and analyzed, for different temperatures and gate voltages.

Balev, O. G.; Vasko, F. T.

2010-06-01

409

Hot Stars in the Galactic Halo  

NASA Astrophysics Data System (ADS)

The stars that comprise a halo around our Galaxy are intriguing; they have abundances of elements that suggest they are old. The properties of these "hot stars" and similar stars in other galaxies challenge the current, well-established theory of stellar evolution in many ways. In this book, experts contribute up-to-date and comprehensive reviews of the major topics in the field. They study the collective properties of these stars that provide important revelations for many areas of astrophysics--including how our Galaxy was formed. The contributors also reveal the exciting renaissance occurring in their studies owing to important new observations with the Hubble Space Telescope and ASTRO1 and to techniques recently developed for ground-based observations. Advances in computers have also recently led to a far more detailed and complete theoretical understanding of stellar evolution. This book will be of interest to researchers and graduate students in astronomy and astrophysics.

Adelman, Saul J.; Upgren, Arthur R.; Adelman, Carol J.

1994-10-01

410

Motel solar hot-water installation--Atlanta, Georgia  

NASA Technical Reports Server (NTRS)

Analysis of hardness of local water, average insolation for site, and daily hot water requirements insures suitability of solar-energy system design. Report describes two units which are designed to supply 81 percent of motel's annual hot water demand based on hypothetical 85 percent occupancy. Report includes drawings, operating and maintenance instructions, and test results for 1 day of operation.

1981-01-01

411

New developments in assessing hot tearing in magnesium alloy castings  

Microsoft Academic Search

High performance magnesium parts produced by permanent mold casting often exhibit hot tear defects. Theoretical prediction of hot tears in magnesium alloys has reached only limited success and further research is necessary to enhance understanding of the fundamental mechanisms associated with the formation of this defect.In this research, numerical modeling of the casting process enabled identification of casting regions susceptible

L. Bichler; C. Ravindran

2010-01-01

412

Preliminary design package for Sunspot Domestic Hot Water Heating System  

NASA Technical Reports Server (NTRS)

The design review includes a drawing list, auto-control logic, measurement definitions, and other document pertaining to the solar heated prototype hot water systems and two heat exchangers. The hot water systems consist of the following subsystems: collector, storage, control transport, auxiliary energy, and site data acquisition.

1976-01-01

413

Prestorage hot water treatments (immersion, rinsing and brushing)  

Microsoft Academic Search

This review summarizes the latest developments in hot water immersion treatment (HWT) and hot water rinsing and brushing (HWRB) technologies. These treatments kill pathogens that cause surface decay, while maintaining fruit quality during prolonged storage and marketing. They also are relatively easy to use, have a short operating time, and are efficient in heat transfer. The cost of a typical

Elazar Fallik

2004-01-01

414

Self-contained hot-hollow cathode gun source assembly  

DOEpatents

A self-contained hot-hollow cathode gun source assembly for use in a vacuum chamber includes a crucible block having a hot-hollow cathode gun mounted underneath and providing a hole for the magnetic deflection of the ion/electron beam into a crucible on top the block.

Zeren, J.D.

1984-08-01

415

Kinetics of hot carrier effects for circuit simulation  

Microsoft Academic Search

Experimental results that enable the transformation of shifts in the MOS transistor model parameters obtained from DC hot carrier stress to equivalent shifts due to transient stress during circuit operation are presented. This is necessary for simulating the long-term stability of circuits with respect to hot carrier degradation. Results of further experiments and simulations designed to provide physical insight into

S. Aur

1989-01-01

416

RESONANT FARADAY ROTATION IN A HOT LITHIUM VAPOR  

E-print Network

propagation. This is illustrated in Fig. 1.1. Michael Faraday discovered this magneto-optical rotationRESONANT FARADAY ROTATION IN A HOT LITHIUM VAPOR By SCOTT RUSSELL WAITUKAITIS A Thesis Submitted: #12;Abstract I describe a study of Faraday rotation in a hot lithium vapor. I begin by dis- cussing

Cronin, Alex D.

417

Self-contained hot-hollow cathode gun source assembly  

DOEpatents

A self-contained hot-hollow cathode gun source assembly for use in a vacuum chamber includes a crucible block having a hot-hollow cathode gun mounted underneath and providing a hole for the magnetic deflection of the ion/electron beam into a crucible on top the block.

Zeren, Joseph D. (Boulder, CO)

1986-01-01

418

Solar Hot Water for Motor Inn--Texas City, Texas  

NASA Technical Reports Server (NTRS)

Final report describes solar domestic-hot-water heater installation at LaQuinta Motor Inn, Texas City, Texas which furnished 63% of total hot-water load of new 98-unit inn. Report presents a description of system, drawings and photographs of collectors, operations and maintenance instructions, manufacturers' specifications for pumps, and an engineer's report on performance.

1982-01-01

419

21 CFR 880.6085 - Hot/cold water bottle.  

Code of Federal Regulations, 2011 CFR

A hot/cold water bottle is a device intended for medical purposes that is in the form of a container intended to be filled with hot or cold water to apply heat or cold to an area of the body. (b) Classification. Class I (general...

2011-04-01

420

Analysis Model for Domestic Hot Water Distribution Systems: Preprint  

SciTech Connect

A thermal model was developed to estimate the energy losses from prototypical domestic hot water (DHW) distribution systems for homes. The developed model, using the TRNSYS simulation software, allows researchers and designers to better evaluate the performance of hot water distribution systems in homes. Modeling results were compared with past experimental study results and showed good agreement.

Maguire, J.; Krarti, M.; Fang, X.

2011-11-01

421

Effects of surface chemistry on hot corrosion life  

NASA Technical Reports Server (NTRS)

Hot corrosion life prediction methodology based on a combination of laboratory test data and field service turbine components, which show evidence of hot corrosion, were examined. Components were evaluated by optical metallography, scanning electron microscopy (SEM), and electron micropulse (EMP) examination.

Fryxell, R. E.; Gupta, B. K.

1984-01-01

422

Milestones Towards Hot CMC Structures for Operational Space Rentry Vehicles  

Microsoft Academic Search

Hot structures made of ceramic matrix composites (CMC) for space reentry vehicles play a key role regarding feasibility of advanced and reusable future space transportation systems. Thus realization of applicable flight hardware concerning hot primary structures like a nose cap or body flaps and thermal protection systems (TPS) requires system competence w.r.t. sophisticated know how in material processing, manufacturing and

H. Hald; H. Weihs; T. Reimer

2002-01-01

423

2. HOT METAL BRIDGE (ACROSS THE MONONGAHELA RIVER) AND CARRIE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. HOT METAL BRIDGE (ACROSS THE MONONGAHELA RIVER) AND CARRIE FURNACES No. 3 AND No. 4 FROM THE TOP OF WATER TOWER. THE EDGAR THOMSON WORKS IS VISIBLE BEYOND HOT METAL BRIDGE. Jet Lowe, Photographer, 1989. - U.S. Steel Homestead Works, Blast Furnace Plant, Along Monongahela River, Homestead, Allegheny County, PA

424

Research Article Microbial Community Structures of Novel Icelandic Hot  

E-print Network

microbial biomass and diversity when compared to thermophilic (*60°C) springs. Ordination anal- ysis with pH. Key Words: Microbial diversity--PhyloChip G3--Acidophilic--Thermophilic--Hot springsResearch Article Microbial Community Structures of Novel Icelandic Hot Spring Systems Revealed

Low, Steven H.

425

Tour of Park Geology: Hot Springs/Geothermal  

NSDL National Science Digital Library

This National Park Service (NPS) site provides links to National Parks with hot springs or geothermal activity. Where appropriate, links are provided to geology, visitor information, photographs, park maps, multimedia resources, geologic research, and additional links. Parks at this site include Hot Springs National Park, Lassen Volcano National Park, and more.

426

A hydrothermal hot-pressing method: Apparatus and application  

Microsoft Academic Search

Loose particles occurring in sediment are transformed into sedimentary rock by a process termed lithification, which is a chemical process that reduces the original porosity by compaction and cementation [1]. A hydrothermal hot-pressing method is intended for artificial lithification. In this study, silica powder including mineralizer solution is compressed under hydrothermal conditions from outside an autoclave for hydrothermal hot-pressing and

N. Yamasaki; K. Yanagisawa; M. Nishioka; S. Kanahara

1986-01-01

427

Use of low temperature blowers for recirculation of hot gases  

DOEpatents

An apparatus is described for maintaining motors at low operating temperatures during recirculation of hot gases in fuel cell operations and chemical processes such as fluidized bed coal gasification. The apparatus includes a means for separating the hot process gas from the motor using a secondary lower temperature gas, thereby minimizing the temperature increase of the motor and associated accessories.

Maru, H.C.; Forooque, M.

1982-08-19

428

ATMOSPHERIC CHARACTERIZATION OF THE HOT JUPITER KEPLER-13Ab  

E-print Network

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 ...

Shporer, Avi

429

Can Terrestrial Planets Form in Hot-Jupiter Systems?  

E-print Network

Models of terrestrial planet formation in the presence of a migrating giant planet have challenged the notion that hot-Jupiter systems lack terrestrial planets. We briefly review this issue and suggest that hot-Jupiter systems should be prime targets for future observational missions designed to detect Earth-sized and potentially habitable worlds.

Martyn J. Fogg; Richard P. Nelson

2007-10-19

430

Modeling the emergence of the 'hot zones': tuberculosis and the ...  

E-print Network

Sep 19, 2004 ... drug resistance do not adequately capture the complexity of the epi- demiology of the hot zones, and cannot be used to understand their evolution. Farmer and .... emerged as a result of incomplete adherence, inadequate drug supply .... not improved, new hot zones will continue to emerge (Fig. 3c). In the.

2004-09-10

431

Particle simulation of nonlocal transport in laser hot spot  

Microsoft Academic Search

Relaxation of a hot spot has been studied in the regime of a nonlocal electron transport using PIC simulations with e-e and e-i collisions. This work leads to a practical model for a heat flux inhibition in laser heated plasma. We present results of a hot spot relaxation for a small temperature perturbation in comparison with analytical theory and delta

F. Detering; V. Yu. Bychenkov; E. Fourkal; W. Rozmus; R. Sydora; C. E. Capjack

2000-01-01

432

THE IMPACT OF "HOT COGNITION" IN PROFESSIONAL PERFORMANCE  

E-print Network

. KEYWORDS Hot cognition, User Psychological Profile, Personality Traits, Emotional Intelligence, Soft Skills and soft skills5 . They do not stimulate 1 cognition colored by affect - emotional intelligence, personality traits and soft skills. 2 affective information which comes with a hot cognition process. 3

Paris-Sud XI, Université de

433

Prototype solar heating and cooling systems including potable hot water  

NASA Technical Reports Server (NTRS)

Progress is reviewed in the development, delivery, and support of two prototype solar heating and cooling systems including potable hot water. The system consisted of the following subsystems: collector, auxiliary heating, potable hot water, storage, control, transport, and government-furnished site data acquisition.

1978-01-01

434

Solar Thermal Energy: Design a Solar Hot Water Heater System  

NSDL National Science Digital Library

This classroom activity from the Advanced Technology Environmental and Energy Center (ATEEC) has students examine a collector and tank for a solar hot water heater and estimate the amount of energy and money saved by replacing the traditional hot water heater. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.

Bullwinkel, Matt

2013-01-08

435

Visualizing Cosmological Concepts Using the Analog of a Hot Liquid  

ERIC Educational Resources Information Center

We have used the expansion process of hot milk, which has similarities with the cosmic expansion, to facilitate easier and better visualization and teaching of cosmological concepts. Observations of milk are used to illustrate phenomena related to the Planck era, the standard hot big bang model, cosmic inflation, problems with the formation of

Yusofi, E.; Mohsenzadeh, M.

2010-01-01

436

Prospective Evaluation of Hot Flashes during Pregnancy and Postpartum  

PubMed Central

Objective To determine the prevalence, course, and risk factors for hot flashes during pregnancy and postpartum. Study Design Women (N=429) were assessed prospectively during pregnancy (weeks 20, 30, 36) and up to a year after delivery (weeks 2, 12, 26, 52). A clinical interview, physical measurements, and questionnaires were administered at each visit. Results Thirty-five percent of women reported hot flashes during pregnancy and 29% reported hot flashes after delivery. In multivariable binomial mixed effects models, women who were younger (per year: OR(95%CI): 0.94(0.880.99)), had a higher pre-pregnancy body mass index (BMI; per unit increase: OR(95%CI): 1.05(1.011.10)), and had less than a college education (OR(95%CI): 2.58(1.195.60); vs. college) were more likely to report hot flashes during pregnancy. Higher depressive symptoms were associated with hot flashes during pregnancy (per unit increase: OR(95%CI): 1.08(1.041.13)) and after birth (OR(95%CI): 1.19(1.141.25), multivariable models). Conclusion Hot flashes, typically considered a menopausal symptom, were reported by over a third of women during pregnancy and/or postpartum. Predictors of hot flashes during this reproductive transition, including depressive symptoms, low education, and higher BMI are similar to those experienced during menopause. Future work should investigate the role of hormonal and affective factors in hot flashes during pregnancy and postpartum. PMID:24035604

Thurston, Rebecca C.; Luther, James F.; Wisniewski, Stephen R.; Eng, Heather; Wisner, Katherine L.

2014-01-01

437

Dynamical Interactions Make Hot Jupiters in Open Star Clusters  

E-print Network

Explaining the origin and evolution of exoplanetary "hot Jupiters" remains a significant challenge. One possible mechanism for their production is planet-planet interactions, which produces hot Jupiters from planets born far from their host stars but near their dynamical stability limits. In the much more likely case of planets born far from their dynamical stability limits, can hot Jupiters can be formed in star clusters? Our N-body simulations of planetary systems inside star clusters answer this question in the affirmative, and show that hot Jupiter formation is not a rare event. We detail three case studies of the dynamics-induced births of hot Jupiters on highly eccentric orbits that can only occur inside star clusters. The hot Jupiters' orbits bear remarkable similarities to those of some of the most extreme exoplanets known: HAT-P-32 b, HAT-P-2 b, HD 80606 b and GJ 876 d. If stellar perturbations formed these hot Jupiters then our simulations predict that these very hot, inner planets are sometimes acc...

Shara, Michael M; Mardling, Rosemary A

2014-01-01

438

Neural network modelling of hot deformation of austenite  

E-print Network

majority of steels contain low concentrations of alloy elements, and are shaped using hot-rolling. Steels It is known that the hot deformation behaviour of austenite in steels is a complicated process, dependent noise in the data. The validity of the model was evaluated by testing against six compositions of carbon-manganese

Cambridge, University of

439

Hot-Melt Application for Functional Compounds on Technical Textiles  

Microsoft Academic Search

Application of hot-melt products for the production of functional technical textiles is increasing rapidly. The system in comparison to the wet lamination process is able to run at high speeds. Increasing fields of application are realised, such as for the automotive industry, for interlinings, medical textiles, and other clothing applications. The coating machinery industry and suppliers of special hot melt

Andrea Glawe; Regina Reuscher; Regina Kppe; Thomas Kolbusch

2003-01-01

440

Modeling Hot and Cold Planets: Activity A Modeling Hot and Cold Planets  

NSDL National Science Digital Library

In this activity, student teams design small-scale physical models of hot and cold planets, (Venus and Mars), and learn that small scale models allow researchers to determine how much larger systems function. There is both a team challenge and competition built into this activity. Experimental findings are then used to support a discussion of human outposts on Mars. The resource includes an experimental design guide for students as well as a handout outlining a method for the design of controlled experiments, and student data sheets. Student questions and an essay assignment are provided as classroom assessments. This is Activity A in the second module, titled "Modeling hot and cold planets," of the resource, "Earth Climate Course: What Determines a Planet's Climate?" The course aims to help students to develop an understanding of our environment as a system of human and natural processes that result in changes that occur over various space and time scales.

441

Ultraviolet Fe VII absorption lines in planetary nebula nuclei, hot subdwarfs, and hot degenerate objects  

NASA Astrophysics Data System (ADS)

Results are reported from a search for Fe VII absorption lines in data from high-dispersion IUE-SWP observations of PN nuclei (PNN), hot subdwarfs (HSDs), and hot white dwarfs (HWDs). The data-reduction techniques employed are outlined, and the results are presented in extensive tables and sample spectra and characterized in detail. Absorption in at least one of the four Fe VII lines above 120 nm wavelength is found in 22 of 51 PNN, and possibly in 10 HSDs, in the pulsating HWD PG 1159 - 035, and in the PNN K1 - 16. It is concluded that Fe VII is more common in WD progenitors such as PNN than previously predicted and is especially typical of the more luminous low-gravity stars.

Feibelman, Walter A.; Bruhweiler, Frederick C.

1990-07-01

442

Ultraviolet Fe VII absorption lines in planetary nebula nuclei, hot subdwarfs, and hot degenerate objects  

NASA Technical Reports Server (NTRS)

Results are reported from a search for Fe VII absorption lines in data from high-dispersion IUE-SWP observations of PN nuclei (PNN), hot subdwarfs (HSDs), and hot white dwarfs (HWDs). The data-reduction techniques employed are outlined, and the results are presented in extensive tables and sample spectra and characterized in detail. Absorption in at least one of the four Fe VII lines above 120 nm wavelength is found in 22 of 51 PNN, and possibly in 10 HSDs, in the pulsating HWD PG 1159 - 035, and in the PNN K1 - 16. It is concluded that Fe VII is more common in WD progenitors such as PNN than previously predicted and is especially typical of the more luminous low-gravity stars.

Feibelman, Walter A.; Bruhweiler, Frederick C.

1990-01-01

443

Hot flow anomaly formation by magnetic deflection. [regions of hot plasma in earth magnetosphere  

NASA Technical Reports Server (NTRS)

Hot flow anomalies (HFAs) are localized plasma structures observed in the solar wind and magnetosheath near the earth's quasi-parallel bow shock. This paper presents one-dimensional hybrid computer simulations illustrating a formation mechanism for HFAs in which the single hot ion population results from a spatial separation of two counterstreaming ion beams. The higher-density cooler regions are dominated by the background (solar wind) ions, and the lower-density hotter internal regions are dominated by the beam ions. The spatial separation of the beam and background is caused by the deflection of the ions in large-amplitude magnetic fields which are generated by ion/ion streaming instabilities.

Onsager, T. G.; Thomsen, M. F.; Winske, D.

1990-01-01

444

Evaluation of coefficients of friction in hot stamping by hot flat drawing test  

Microsoft Academic Search

The coefficient of friction in hot stamping was measured using a tribosimulator. Simulative experiments were carried out using SPHC steel and 22MnB5 steel under dry conditions. The coefficient of friction of 22MnB5 steel was higher than that of SPHC steel. The obtained coefficients of friction were effective for use in numerical simulations by finite element analysis. The obtained coefficients of

A. Yanagida; A. Azushima

2009-01-01

445

KFC Server: interactive forecasting of protein interaction hot spots.  

PubMed

The KFC Server is a web-based implementation of the KFC (Knowledge-based FADE and Contacts) model-a machine learning approach for the prediction of binding hot spots, or the subset of residues that account for most of a protein interface's; binding free energy. The server facilitates the automated analysis of a user submitted protein-protein or protein-DNA interface and the visualization of its hot spot predictions. For each residue in the interface, the KFC Server characterizes its local structural environment, compares that environment to the environments of experimentally determined hot spots and predicts if the interface residue is a hot spot. After the computational analysis, the user can visualize the results using an interactive job viewer able to quickly highlight predicted hot spots and surrounding structural features within the protein structure. The KFC Server is accessible at http://kfc.mitchell-lab.org. PMID:18539611

Darnell, Steven J; LeGault, Laura; Mitchell, Julie C

2008-07-01

446

The design and fabrication of a calibrated hot box apparatus  

SciTech Connect

A second generation research calibrated hot box was designed and constructed at the University of Massachusetts`s Building Energy Research Laboratory. The hot box was built to meet the test methodologies specified in the American Society for Testing and Materials (ASTM) Standard Test Methods C 976 for calibrated hot boxes and C 1199 for fenestration system hot box test methods. The hot box has the capability of simulating both parallel and perpendicular weather side wind directions on building assemblies, including fenestration (window and door) systems. The weather side chamber has a temperature range of {minus}23.3 C to 60 C and the room side chamber has a temperature range of 21.1 C to 60 C. The design, fabrication, and instrumentation are described in detail.

Gatland, S.D. II [Center for Applied Engineering, Inc., St. Petersburg, FL (United States); Goss, W.P. [Univ. of Massachusetts, Amherst, MA (United States); Curcija, D. [Carli Inc., Amherst, MA (United States)

1997-11-01

447

Hot electron photoluminescence in GaAs crystals  

NASA Astrophysics Data System (ADS)

The spectrum and the linear polarization of photoluminescence of hot electrons in GaAs crystals were investigated. Oscillations in the hot photoluminescence (HPL) spectrum due to the subsequent emission of LO-phonons were observed. The study of HPL depolarization in an external magnetic field yielded the scattering time due to the emission of a LO-phonon by a hot electron in the ?-valley ( ??0 = 1 10 -13 sec) as well as the ?- L intervalley scattering time. The radiative recombination of hot electrons created in the central ?-valley via the subsidiary L-valley was observed. The distribution function of hot electrons in a wide energy range was evaluated from the spectra.

Mirlin, D. N.; Karlik, I. Ja.; Nikitin, L. P.; Reshina, I. I.; Sapega, V. F.

1981-03-01

448

The KELT-North Transit Survey: Hot Planets around Hot, Bright Stars  

NASA Astrophysics Data System (ADS)

The KELT-North is a small-aperture, wide-angle automated telescope located in southern Arizona that has been surveying roughly 40% of the northern sky for transiting planets since 2006. By virtue of its small aperture and large field-of-view, KELT is most sensitive to hot Jupiters transiting relatively bright (V~8-10), and thus relatively hot stars. Roughly half of the over 200,000 dwarf stars targeted by KELT are hotter than 6250K; such stars pose novel challenges, but also provide unique opportunities. I will present the first transiting substellar companions discovered by KELT, focusing in detail on a few particularly interesting systems. I will discuss our plans for determining the frequency and demographics of short-period companions to hot stars from KELT; comparison with similar results for cooler stars may provide important constraints on theories of the emplacement and tidal evolution of low-mass stellar companions. Finally, I will speculate on how the lessons learned from KELT may inform the target selection and survey strategies for the TESS mission.This work was supported by NSF CAREER grant AST-1056524.

Gaudi, B. Scott; Beatty, Thomas G.; Eastman, Jason D.; Lund, Michael; Penny, Matthew; Pepper, Joshua; Rodriguez, Joseph E.; Siverd, Robert; Stassun, Keivan; Stevens, Daniel J.; KELT-North Collaboration

2015-01-01

449

Meteorology of Jupiter's Equatorial Hot Spots and Plumes from Cassini  

NASA Technical Reports Server (NTRS)

We present an updated analysis of Jupiter's equatorial meteorology from Cassini observations. For two months preceding the spacecraft's closest approach, the Imaging Science Subsystem (ISS) onboard regularly imaged the atmosphere. We created time-lapse movies from this period in order to analyze the dynamics of equatorial hot spots and their interactions with adjacent latitudes. Hot spots are relatively cloud-free regions that emit strongly at 5 lm; improved knowledge of these features is crucial for fully understanding Galileo probe measurements taken during its descent through one. Hot spots are quasistable, rectangular dark areas on visible-wavelength images, with defined eastern edges that sharply contrast with surrounding clouds, but diffuse western edges serving as nebulous boundaries with adjacent equatorial plumes. Hot spots exhibit significant variations in size and shape over timescales of days and weeks. Some of these changes correspond with passing vortex systems from adjacent latitudes interacting with hot spots. Strong anticyclonic gyres present to the south and southeast of the dark areas appear to circulate into hot spots. Impressive, bright white plumes occupy spaces in between hot spots. Compact cirrus-like 'scooter' clouds flow rapidly through the plumes before disappearing within the dark areas. These clouds travel at 150-200 m/s, much faster than the 100 m/s hot spot and plume drift speed. This raises the possibility that the scooter clouds may be more illustrative of the actual jet stream speed at these latitudes. Most previously published zonal wind profiles represent the drift speed of the hot spots at their latitude from pattern matching of the entire longitudinal image strip. If a downward branch of an equatorially-trapped Rossby wave controls the overall appearance of hot spots, however, the westward phase velocity of the wave leads to underestimates of the true jet stream speed.

Choi, David Sanghun; Showman, Adam P.; Vasavada, Ashwin R.; Simon-Miller, Amy A.

2013-01-01

450

40 CFR 420.120 - Applicability; description of the hot coating subcategory.  

Code of Federal Regulations, 2010 CFR

...description of the hot coating subcategory. 420...GUIDELINES AND STANDARDS IRON AND STEEL MANUFACTURING...SOURCE CATEGORY Hot Coating Subcategory 420...not applicable to hot coating operations with wastewater...case-by-case basis based upon the...

2010-07-01

451

48 CFR 952.225-70 - Subcontracting for nuclear hot cell services.  

Code of Federal Regulations, 2014 CFR

... false Subcontracting for nuclear hot cell services. 952.225-70 Section 952...225-70 Subcontracting for nuclear hot cell services. As prescribed in 925.7004...contracts: Subcontracting for Nuclear Hot Cell Services (MAR 1993) (a)...

2014-10-01

452

48 CFR 952.225-70 - Subcontracting for nuclear hot cell services.  

Code of Federal Regulations, 2010 CFR

... false Subcontracting for nuclear hot cell services. 952.225-70 Section 952...225-70 Subcontracting for nuclear hot cell services. As prescribed in 925.7004...contracts: Subcontracting for Nuclear Hot Cell Services (MAR 1993) (a)...

2010-10-01

453

48 CFR 952.225-70 - Subcontracting for nuclear hot cell services.  

Code of Federal Regulations, 2012 CFR

... false Subcontracting for nuclear hot cell services. 952.225-70 Section 952...225-70 Subcontracting for nuclear hot cell services. As prescribed in 925.7004...contracts: Subcontracting for Nuclear Hot Cell Services (MAR 1993) (a)...

2012-10-01

454

48 CFR 952.225-70 - Subcontracting for nuclear hot cell services. >  

Code of Federal Regulations, 2011 CFR

... false Subcontracting for nuclear hot cell services. > 952.225-70 Section...225-70 Subcontracting for nuclear hot cell services.> As prescribed in 925...contracts: Subcontracting for Nuclear Hot Cell Services (MAR 1993) (a)...

2011-10-01

455

48 CFR 952.225-70 - Subcontracting for nuclear hot cell services.  

Code of Federal Regulations, 2013 CFR

... false Subcontracting for nuclear hot cell services. 952.225-70 Section 952...225-70 Subcontracting for nuclear hot cell services. As prescribed in 925.7004...contracts: Subcontracting for Nuclear Hot Cell Services (MAR 1993) (a)...

2013-10-01

456

78 FR 9785 - Airworthiness Directives; Lindstrand Hot Air Balloons Ltd Appliances  

Federal Register 2010, 2011, 2012, 2013, 2014

...2120-AA64 Airworthiness Directives; Lindstrand Hot Air Balloons Ltd Appliances AGENCY: Federal...directive (AD) for certain Lindstrand Hot Air Balloons Ltd female ACME threaded hose...identified in this AD, contact Lindstrand Hot Air Balloons Ltd, Maesbury Road,...

2013-02-12

457

77 FR 26600 - WTO Dispute Settlement Proceeding Regarding United States-Countervailing Measures on Certain Hot...  

Federal Register 2010, 2011, 2012, 2013, 2014

...States-- Countervailing Measures on Certain Hot-Rolled Carbon Steel Flat Products From...countervailing measures regarding certain hot-rolled carbon steel flat products from...countervailing measures regarding certain hot-rolled carbon steel flat products...

2012-05-04

458

77 FR 49477 - WTO Dispute Settlement Proceeding Regarding United States-Countervailing Measures on Certain Hot...  

Federal Register 2010, 2011, 2012, 2013, 2014

...States-- Countervailing Measures on Certain Hot-Rolled Carbon Steel Flat Products From...countervailing measures regarding certain hot-rolled carbon steel flat products from...countervailing measures regarding certain hot-rolled carbon steel flat products...

2012-08-16

459

78 FR 78962 - Criteria for a Recommended Standard; Occupational Exposure to Heat and Hot Environments; Draft...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Standard; Occupational Exposure to Heat and Hot Environments; Draft Criteria Document Availability...Standard: Occupational Exposure to Heat and Hot Environments for public comment. To view...Standard: Occupational Exposure to Heat and Hot Environments''. Special emphasis...

2013-12-27

460

77 FR 64763 - Airworthiness Directives; Lindstrand Hot Air Balloons Ltd Appliances  

Federal Register 2010, 2011, 2012, 2013, 2014

...2120-AA64 Airworthiness Directives; Lindstrand Hot Air Balloons Ltd Appliances AGENCY: Federal...directive (AD) for certain Lindstrand Hot Air Balloons Ltd female ACME threaded hose...in this proposed AD, contact Lindstrand Hot Air Balloons Ltd., Maesbury...

2012-10-23

461

Particulate hot gas stream cleanup technical issues  

SciTech Connect

This is the tenth in a series of quarterly reports describing the activities performed under Contract No. DE-AC21-94MC31160. Analyses of Hot Gas Stream Cleanup (HGCU) ashes and descriptions of filter performance address aspects of filter operation that are apparently linked to the characteristics of the collected ash or the performance of the ceramic bed filter elements. Task I is designed to generate a data base of the key characteristics of ashes collected from operating advanced particle filters (APFS) and to relate these ash properties to the operation and performance of these filters. Task 2 concerns testing and failure analysis of ceramic filter elements. Under Task I during the past quarter, analyses were performed on a particulate sample from the Transport Reactor Demonstration Unit (TRDU) located at the University of North Dakota Energy and Environmental Research Center. Analyses are in progress on ash samples from the Advanced Particulate Filter (APF) at the Pressurized Fluidized-Bed Combustor (PFBC) that was in operation at Tidd and ash samples from the Pressurized Circulating Fluid Bed (PCFB) system located at Karhula, Finland. A site visit was made to the Power Systems Development Facility (PSDF) to collect ash samples from the filter vessel and to document the condition of the filter vessel with still photographs and videotape. Particulate samples obtained during this visit are currently being analyzed for entry into the Hot Gas Cleanup (HGCU) data base. Preparations are being made for a review meeting on ash bridging to be held at Department of Energy Federal Energy Technology Center - Morgantown (DOE/FETC-MGN) in the near future. Most work on Task 2 was on hold pending receipt of additional funds; however, creep testing of Schumacher FT20 continued. The creep tests on Schumacher FT20 specimens just recently ended and data analysis and comparisons to other data are ongoing. A summary and analysis of these creep results will be sent out shortly. Creep testing of two Refractron 326 specimens is now in progress. Among the tasks expected to be completed this quarter are analysis of the creep data obtained thus far, microstructural analysis of Refractron 326 and Schumacher FT20, definition of bending loads on candle filters, and characterization of additional candle filters from Karhula.

NONE

1998-09-01

462

Atmospheric Heat Redistribution on Hot Jupiters  

NASA Astrophysics Data System (ADS)

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 daysidesand thus have a larger day-night temperature contrastthan 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 irradiation 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, ?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 \\tau _{wave}\\sim \\sqrt{\\tau _{rad}/\\Omega }, where ?rad is the radiative relaxation time and ? is the planetary rotation frequency. Alternatively, this transition criterion can be expressed as ?rad ~ ?vert, where ?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 ?rad and the horizontal day-night advection timescale, ?adv. Only because ?adv ~ ?vert for hot Jupiters does the commonly assumed timescale comparison between ?rad and ?adv yield approximately correct predictions for the heat redistribution efficiency.

Perez-Becker, Daniel; Showman, Adam P.

2013-10-01

463

Atmospheric Heat Redistribution on Hot Jupiters  

NASA Astrophysics Data System (ADS)

Infrared lightcurves 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. We present a two-layer 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 irradiation 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 that shows that the timescale for gravity waves to propagate horizontally over planetary scales, ?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 ?wave ~ (?rad/?)1/2, where ?rad is the radiative relaxation time, and ? is the planetary rotation frequency. Alternatively, this transition criterion can be expressed in terms of ?vert, the timescale for a fluid parcel to move vertically over the difference in day-night thickness. The transition then occurs when ?rad ~ ?vert. These results subsume the more widely used timescale comparison for estimating heat redistribution efficiency between ?rad and the timescale for large-scale horizontal advection, ?adv. Only because ?adv ~ ?vert for hot Jupiters does the commonly assumed timescale comparison between ?rad and ?adv yield approximately correct predictions for the heat redistribution efficiency.

Perez-Becker, Daniel; Showman, A. P.

2013-10-01

464

Atmospheric Heat Redistribution on Hot Jupiters  

NASA Astrophysics Data System (ADS)

Infrared lightcurves 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. We present a two-layer 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 irradiation 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 that shows that the timescale for gravity waves to propagate horizontally over planetary scales, ?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 ?wave ~ (?rad/?)1/2, where ?rad is the radiative relaxation time, and ? is the planetary rotation frequency. Alternatively, this transition criterion can be expressed in terms of ?vert, the timescale for a fluid parcel to move vertically over the difference in day-night thickness. The transition then occurs when ?rad ~ ?vert. These results subsume the more widely used timescale comparison for estimating heat redistribution efficiency between ?rad and the timescale for large-scale horizontal advection, ?adv. Only because ?adv ~ ?vert for hot Jupiters does the commonly assumed timescale comparison between ?rad and ?adv yield approximately correct predictions for the heat redistribution efficiency. We show that the ?rad vs. ?adv comparison is a poor predictor for heat redistribution efficiency in the general case where ?vert and ?adv are different.

Perez-Becker, D.; Showman, A. P.

2013-12-01

465

Tamavidin 2-HOT, a highly thermostable biotin-binding protein.  

PubMed

Tamavidin 2 is a fungal tetrameric protein that binds with high affinity to biotin, like avidin and streptavidin. We replaced asparagine-115, which lies in a subunit-subunit interface of tamavidin 2, with cysteine to generate the novel, highly thermostable protein tamavidin 2-HOT. Tamavidin 2-HOT retained more than 80% of its biotin-binding activity even after incubation at 99.9C for 60min and was fully active in 70% dimethylsulfoxide for 30min, whereas in these harsh conditions, avidin, streptavidin, and tamavidin 2 lost their activities (less than 20% of their biotin-binding activities). The Tm in which the biotin-binding activity becomes half of tamavidin 2-HOT was 105C, at least 20C higher than those of avidin, streptavidin, and tamavidin 2. Because a reducing agent removed the thermal stability of tamavidin 2-HOT, the N115C mutation likely created disulfide bridges that stabilized inter-subunit associations. Tamavidin 2-HOT is efficiently produced in the soluble form by Escherichia coli for practical use. The isoelectric point of tamavidin 2-HOT (7.4) is sufficiently low to reduce the chance for non-specific binding of non-target molecules due to high positive charges. Therefore, tamavidin 2-HOT may be useful in diverse novel applications that take advantage of its high biotin-binding capability that can withstand harsh conditions. PMID:24211408

Takakura, Yoshimitsu; Suzuki, Junko; Oka, Naomi; Kakuta, Yoshimitsu

2014-01-01

466

Hot-spot heating in central-station arrays  

NASA Technical Reports Server (NTRS)

Hot spot tests performed on the Sacramento Municipal Utility District (SMUD) verificaton array show that current imbalance occurs, resulting in significant hot spot heating. One cause of current imbalance is differences in the average shunt resistances of parallel cell strings due to cell shunt resistance variations. In depth hot spot tests are performed on the verification array with bypass diodes. The tests had several objectives: (1) a comparison of hot spot temperatures achieved under field conditions with those obtained with the present laboratory hot spot test using similar modules; (2) an assessment of current imbalance versus cross tie frequency; and (3) an assessment of different shadow patterns and shadow densities. Instrumented modules are used to vary the number of cross ties and to measure the test-cell current and back-bias voltage. The widths, lengths, and densities of the shadows are varied to maximize the back bias voltage at maximum power current. An infrared camera is used to indicate the existence of hot spots and estimate temperature increases in conjunction with thermocouples. The results of these hot spot tests indicate a sensitivity of back bias heating to the shadow size (amount of cell coverage) and density.

Gonzalez, C. C.

1983-01-01

467

HOT GAS HALOS IN EARLY-TYPE FIELD GALAXIES  

SciTech Connect

We use Chandra and XMM-Newton to study the hot gas content in a sample of field early-type galaxies. We find that the L {sub X}-L {sub K} relationship is steeper for field galaxies than for comparable galaxies in groups and clusters. The low hot gas content of field galaxies with L {sub K} {approx_lt} L {sub *} suggests that internal processes such as supernovae-driven winds or active galactic nucleus feedback expel hot gas from low-mass galaxies. Such mechanisms may be less effective in groups and clusters where the presence of an intragroup or intracluster medium can confine outflowing material. In addition, galaxies in groups and clusters may be able to accrete gas from the ambient medium. While there is a population of L {sub K} {approx_lt} L {sub *} galaxies in groups and clusters that retain hot gas halos, some galaxies in these rich environments, including brighter galaxies, are largely devoid of hot gas. In these cases, the hot gas halos have likely been removed via ram pressure stripping. This suggests a very complex interplay between the intragroup/intracluster medium and hot gas halos of galaxies in rich environments, with the ambient medium helping to confine or even enhance the halos in some cases and acting to remove gas in others. In contrast, the hot gas content of more isolated galaxies is largely a function of the mass of the galaxy, with more massive galaxies able to maintain their halos, while in lower mass systems the hot gas escapes in outflowing winds.

Mulchaey, John S. [Observatories of the Carnegie Institution of Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Jeltema, Tesla E., E-mail: mulchaey@obs.carnegiescience.ed, E-mail: tesla@ucolick.or [UCO/Lick Observatories, 1156 High Street, Santa Cruz, CA 95064 (United States)

2010-05-20

468

Bulk properties of ``hot smoker'' plumes  

NASA Astrophysics Data System (ADS)

The hot buoyant fluid from a submarine vent rises as a plume, entraining fluid from the stratified ocean until a height is reached where the driving buoyant force vanishes and shortly thereafter the diluted plume fluid intrudes into the ocean interior at its equilibrium depth. While a large positive heat flux issues from the vent, the potential temperature anomaly of the horizontally spreading fluid at the equilibrium height depends on the oceanic stratification of both salinity and potential temperature, and on the salinity of the source fluid at the vent. For example, in the Atlantic Ocean, the oceanic stratification causes the spreading plume fluid to be cooler and fresher than the surrounding seawater of the same density, while in the Pacific, the spreading fluid is relatively warm. Here the well-known solution for a turbulent plume rising in a linearly stratified environment is used to obtain simple formulae for: (1) the potential temperature anomaly of the horizontally spreading fluid; (2) the heat flux associated with this injection of diluted vent water at this density level; and (3) the nondimensional solution for the evolution of tracer properties (e.g. salinity and potential temperature) in the rising plume.

McDougall, Trevor J.

1990-07-01

469

Sweet Home Alabama: Hot Spot for Phylogeography  

NSDL National Science Digital Library

Phylogeographers use molecular methods to map herpetological biodiversity in the heart of Dixie. In the mid-1990s, the diversity of freshwater fishes, snails, mussels, and turtles endemic to the waterways of Alabama and neighboring states prompted biologists to call for more attention to the region. They noted that conservation measures there were not comparable to efforts being made in tropical locations, even though the aquatic systems of Alabama qualified as hot spots. Now, using molecular methods, phylogeographers are documenting and expanding the understanding of the amphibian biodiversity of the regionâand continuing to call for conservation. Researchers in the field of phylogeography, founded two decades ago, use such strategies as ecological niche modeling and gene sequencing to map where species occur and to determine how they vary genetically across their range. Comparative phylogeographers then look for common genetic breaks across various species. By mapping breaks for many species across a landscape, researchers gain clues about when adaptations may have occurred and what may have prompted them.

Amy Mayer (freelancer;)

2009-04-01

470

Giant loops in hot SYM and holography  

NASA Astrophysics Data System (ADS)

The AdS/CFT correspondence is a powerful tool which can be used, among other things, to explore the strong coupling behaviour of N=4 super Yang-Mills theory with large number of colors. In this work, we look for phase transitions in hot SYM on a spacial three-sphere. In particular, we study the expectation value of the Polyakov loop operator in large completely symmetric and completely antisymmetric representations. A non-zero expectation value for the loop signals that the corresponding representation is confined. We find, for example, that in the deconfined phase of SYM, large enough symmetric representations are confined, while smaller representations are not. This represents a phase transition. On the gravity side of the AdS-CFT duality, the related Maldacena-Wilson loop corresponds to a fundamental string worldsheet suspended into the bulk of AdS from the loop contour at the boundary. When the representation is large, the fundamental string wraps the contour many times, and undergoes a `blow up' to a higher dimensional object, a D-brane. Finite temperature requires a black hole horizon at the center of AdS, and the question of confinement at non-zero temperature translates to asking whether or not the D-brane touches the horizon.

Karczmarek, Joanna

2009-05-01

471

Cool Companions to Hot White Dwarfs  

NASA Astrophysics Data System (ADS)

We describe a near IR photometric search for cool red dwarf companions to hot white dwarfs (WDs). IR photometry offers a sensitive test for low mass main sequence (MS) companions, and our sample of EUV-detected WDs offers a threefold advantage over previous (largely proper motion-selected) samples: (1) the high WD temperatures insure excellent IR flux contrast with cool dwarfs (2) the range of evolutionary parameter space occupied by the WDs is considerably narrowed and (3) the random effects of the intervening ISM provides a complete but reasonably-sized sample. We use detailed DA model atmosphere fits to optical spectra to predict WD K magnitudes and distances, against which we contrast our near IR observations. Our photometric survey reveals several DAs with a K excess, which is most likely caused by a cool, low mass dwarf companion. A few such composites have been found optically among WDs detected in recent EUV All-Sky Surveys. However, IR techniques can probe further down the MS, and to wider separations, where a significantly larger number of companions is expected. Systems showing an IR excess will be followed up to determine the mass and spectral type of the cool companions, leading to better estimates of 1) the low mass MS luminosity function (2) the fraction of WDs with MS companions and (3) the mass ratio distribution in binaries. WD+MS systems are the progenitors of novae, CVs, symbiotics, Ba and CH giants, Feige 24-type systems, dwarf carbon stars, and other interacting binaries.

Green, P. J.; Ali, B.

1998-12-01

472

Hot Massive Stars: The Impact of HST  

E-print Network

We review the contribution of Hubble Space Telescope to the study of hot, luminous stars. Optical and IR imaging have permitted spatially resolved observations of young, massive clusters within Local Group galaxies, such as R136, NGC 3603 and Arches, revealing unprecedented concentrations of very massive O stars. UV spectroscopy of field OB stars in the Magellanic Clouds have provided suitable templates for interpretation of metal-poor star-forming galaxies at high-redshift. Spectacular imaging provides the detailed structure of ejecta nebulae from individual stars, including the Homunculus associated with eta Carinae and M1-67, associated with a Wolf-Rayet star. HST has permitted individual massive stars to be spatially resolved in giant HII regions located beyond the Local Group, such as NGC 604, plus individual clusters, dominated by the light of massive stars within starburst galaxies at larger distances, such as NGC 3125. UV spectroscopy of young, massive clusters in the extremely metal-poor HII galaxy I Zw 18 include signatures of large numbers of Wolf-Rayet stars.

Paul A. Crowther

2007-06-30

473

Dounreay hot particles: the story so far.  

PubMed

The first Dounreay hot particle (hereafter 'Particle') to be formally identified was recovered from the Dounreay foreshore in 1983. A further single Particle was recovered from Sandside beach the following year. Particles have been detected and removed from the Dounreay foreshore regularly since 1984 and from the offshore sediments since 1997. Since 1997, an extensive research and development programme has been undertaken to identify the source of Particles, their movement and lifetimes in the marine environment, and their potential effects on human and environmental health. It is now known that Particles were released to the North Atlantic Ocean in the mid to late 1960s and early 1970s. There is no evidence of an on-going source of Particles from the Dounreay site today. The source of Particles recovered from the Dounreay foreshore and from local beaches is the cache currently residing in marine sediments adjacent to Dounreay. Monitoring and sediment modelling studies indicate that the Dounreay Particles are transported approximately parallel to the coast in a north-easterly direction. Studies to define contact frequencies and risks to human health suggest that the health risks associated with Particles are very low There is, however, a significant perception of risk. UKAEA will define a long-term Particle management programme via the development of a best practical environmental option (BPEO) facilitated through consultation with all stakeholders. PMID:17768316

Dennis, Frank; Morgan, Graeme; Henderson, Fiona

2007-09-01

474

Hot Massive Stars: The Impact of HST  

NASA Astrophysics Data System (ADS)

We review the contribution of Hubble Space Telescope to the study of hot, luminous stars. Optical and IR imaging have permitted spatially resolved observations of young, massive clusters within Local Group galaxies, such as R136, NGC 3603 and Arches, revealing unprecedented concentrations of very massive O stars. UV spectroscopy of field OB stars in the Magellanic Clouds have provided suitable templates for interpretation of metal-poor star-forming galaxies at high-redshift. Spectacular imaging provides the detailed structure of ejecta nebulae from individual stars, including the Homunculus associated with ? Carinae and M1-67, associated with a Wolf-Rayet star. HST has permitted individual massive stars to be spatially resolved in giant HII regions located beyond the Local Group, such as NGC 604, plus individual clusters, dominated by the light of massive stars within starburst galaxies at larger distances, such as NGC 3125. UV spectroscopy of young, massive clusters in the extremely metal-poor HII galaxy I Zw 18 include signatures of large numbers of Wolf-Rayet stars.

Crowther, Paul A.

475

Aural stealth of portable HOT infrared imager  

NASA Astrophysics Data System (ADS)

Further reduction of size, weight and power consumption of the High Operating Temperature (HOT) infrared (IR) Integrated Detector-Dewar-Cooler Assemblies (IDDCA) eventually calls for development of high-speed cryocoolers. In case of integral rotary design, the immediate penalty is the more intensive slapping of compression and expansion pistons along with intensification of micro collisions inherent for the operation of crank-slide linkages featuring ball bearings. Resulting from this is the generation of impulsive vibration export, the spectrum of which features the driving frequency along with numerous multiples covering the entire range of audible frequencies. In a typical design of an infrared imager, the metal light-weight enclosure accommodates a directly mounted IDDCA and an optical train, thus serving as an optical bench and heat sink. This usually results in excitation of structural resonances in the said enclosure and, therefore, in excessive noise generation compromising the aural stealth. The author presents the complex approach to a design of aural undetectable infrared imagers in which the IDDCA is mounted upon the imager enclosure through a silent pad. Special attention is paid to resolving the line of sight stability and heat sinking issues. The demonstration imager relying on Ricor K562S based IDDCA meets the most stringent requirement to 10 meters aural non-detectability distance (per MIL-STD 1474D, Level II) even during boost cooldown phase of operation.

Veprik, Alexander

2013-06-01