Does Aspartic Acid Racemization Constrain the Depth Limit of the Subsurface Biosphere?

Science.gov (United States)

Onstott, T C.; Magnabosco, C.; Aubrey, A. D.; Burton, A. S.; Dworkin, J. P.; Elsila, J. E.; Grunsfeld, S.; Cao, B. H.; Hein, J. E.; Glavin, D. P.;

Limited Genetic Connectivity between Gorgonian Morphotypes along a Depth Gradient.

Directory of Open Access Journals (Sweden)

Federica Costantini

Full Text Available Gorgonian species show a high morphological variability in relation to the environment in which they live. In coastal areas, parameters such as temperature, light, currents, and food availability vary significantly with depth, potentially affecting morphology of the colonies and the structure of the populations, as well as their connectivity patterns. In tropical seas, the existence of connectivity between shallow and deep populations supported the hypothesis that the deep coral reefs could potentially act as (reproductive refugia fostering re-colonization of shallow areas after mortality events. Moreover, this hypothesis is not so clear accepted in temperate seas. Eunicella singularis is one of the most common gorgonian species in Northwestern Mediterranean Sea, playing an important role as ecosystem engineer by providing biomass and complexity to the coralligenous habitats. It has a wide bathymetric distribution ranging from about 10 m to 100 m. Two depth-related morphotypes have been identified, differing in colony morphology, sclerite size and shape, and occurrence of symbiotic algae, but not in mitochondrial DNA haplotypes. In the present study the genetic structure of E. singularis populations along a horizontal and bathymetric gradient was assessed using microsatellites and ITS1 sequences. Restricted gene flow was found at 30-40 m depth between the two Eunicella morphotypes. Conversely, no genetic structuring has been found among shallow water populations within a spatial scale of ten kilometers. The break in gene flow between shallow and deep populations contributes to explain the morphological variability observed at different depths. Moreover, the limited vertical connectivity hinted that the refugia hypothesis does not apply to E. singularis. Re-colonization of shallow water populations, occasionally affected by mass mortality events, should then be mainly fueled by larvae from other shallow water populations.

New 21 cm Power Spectrum Upper Limits From PAPER II: Constraints on IGM Properties at z = 7.7

Science.gov (United States)

Pober, Jonathan; Ali, Zaki; Parsons, Aaron; Paper Team

2015-01-01

Using a simulation-based framework, we interpret the power spectrum measurements from PAPER of Ali et al. in the context of IGM physics at z = 7.7. A cold IGM will result in strong 21 cm absorption relative to the CMB and leads to a 21 cm fluctuation power spectrum that can exceed 3000 mK^2. The new PAPER measurements allow us to rule out extreme cold IGM models, placing a lower limit on the physical temperature of the IGM. We also compare this limit with a calculation for the predicted heating from the currently observed galaxy population at z = 8.

A Water Temperature Simulation Model for Rice Paddies With Variable Water Depths

Science.gov (United States)

Maruyama, Atsushi; Nemoto, Manabu; Hamasaki, Takahiro; Ishida, Sachinobu; Kuwagata, Tsuneo

2017-12-01

A water temperature simulation model was developed to estimate the effects of water management on the thermal environment in rice paddies. The model was based on two energy balance equations: for the ground and for the vegetation, and considered the water layer and changes in the aerodynamic properties of its surface with water depth. The model was examined with field experiments for water depths of 0 mm (drained conditions) and 100 mm (flooded condition) at two locations. Daily mean water temperatures in the flooded condition were mostly higher than in the drained condition in both locations, and the maximum difference reached 2.6°C. This difference was mainly caused by the difference in surface roughness of the ground. Heat exchange by free convection played an important role in determining water temperature. From the model simulation, the temperature difference between drained and flooded conditions was more apparent under low air temperature and small leaf area index conditions; the maximum difference reached 3°C. Most of this difference occurred when the range of water depth was lower than 50 mm. The season-long variation in modeled water temperature showed good agreement with an observation data set from rice paddies with various rice-growing seasons, for a diverse range of water depths (root mean square error of 0.8-1.0°C). The proposed model can estimate water temperature for a given water depth, irrigation, and drainage conditions, which will improve our understanding of the effect of water management on plant growth and greenhouse gas emissions through the thermal environment of rice paddies.

Limit-order book resiliency after effective market orders: spread, depth and intensity

Science.gov (United States)

Xu, Hai-Chuan; Chen, Wei; Xiong, Xiong; Zhang, Wei; Zhou, Wei-Xing; Stanley, H. Eugene

2017-07-01

In order-driven markets, limit-order book (LOB) resiliency is an important microscopic indicator of market quality when the order book is hit by a liquidity shock and plays an essential role in the design of optimal submission strategies of large orders. However, the evolutionary behavior of LOB resilience around liquidity shocks is not well understood empirically. Using order flow data sets of Chinese stocks, we quantify and compare the LOB dynamics characterized by the bid-ask spread, the LOB depth and the order intensity surrounding effective market orders with different aggressiveness. We find that traders are more likely to submit effective market orders when the spreads are relatively low, the same-side depth is high, and the opposite-side depth is low. Such phenomenon is especially significant when the initial spread is 1 tick. Although the resiliency patterns show obvious diversity after different types of market orders, the spread and depth can return to the sample average within 20 best limit updates. The price resiliency behavior is dominant following aggressive market buy orders, while the price continuation behavior is dominant following less-aggressive market sell orders. Moreover, the resiliency stimulus of buy-sell shock is asymmetrical. The intensities of limit sell orders after market buy orders’ shock are always higher than the intensities of limit buy orders after market sell orders’ shock. The resiliency behavior of spread and depth is linked to limit order intensity.

Temperature and depth error in the mechanical bathythermograph data from the Indian Ocean

Digital Repository Service at National Institute of Oceanography (India)

Gautham, S.; Pankajakshan, T.

are used to understand the observed errors in temperature and depth of MBT data. The estimated error from the match up data shows that both temperature and depth measurement of MBT are over estimated, compared to CTD measurements. Estimated thermal bias...

Measurements of europium-152 depth profile of stone embankments exposed the Nagasaki atomic bomb for neutron spectrum analysis

International Nuclear Information System (INIS)

Tatsumi-Miyajima, Junko; Shimasaki, Tatsuya; Okajima, Shunzo; Takada, Jitsuya; Yoshida, Masahiro; Takao, Hideaki; Okumura, Yutaka; Nakazawa, Masaharu.

1990-01-01

Quantitative measurement of neutron-induced radionuclide of 152 Eu in rocks near the hypocenter (ground center of the atomic bomb explosion) in Nagasaki was performed to obtain the depth profiles and calculate the neutron energy spectrum. Core samples were drilled and taken from the stone embankments on both sides of river within a radius of 500 m from the hypocenter. After cutting each core into about 27 mm-thick sections, each section was measured its gamma-ray spectrum with a pure germanium semiconductor detector and analyzed a content of natural europium by the activation method. The highest value 8.0 x 10 -2 Bq/μg of 152 Eu at the time of the blast was obtained from the surface plates of rock cores collected near the hypocenter. The surface activity of cores was reduced with increasing the slant distances from the hypocenter. The slopes of the depth profiles were similar among samples taken from the same location. In order to analyze the depth profile of 152 Eu activity in rock andesite, experiments using a fast neutron reactor and thermal neutron reactor were carried out. Comparing the measurements on the A-bomb exposure rock with the simulated results at the reactors, among the experiments, the depth profile using the neutron moderator of 10 mm polyethylene was closed to that obtained from the A-bomb exposed samples. The experiment of thermal neutron incidence only could not reproduce the profiles from the A-bomb exposed samples. This fact indicates that the depth profiles of 152 Eu in rock exposed to the A-bomb include valuable information concerning the neutron spectrum and intensity. (author)

Depth perception: the need to report ocean biogeochemical rates as functions of temperature, not depth

Science.gov (United States)

Brewer, Peter G.; Peltzer, Edward T.

2017-08-01

For over 50 years, ocean scientists have oddly represented ocean oxygen consumption rates as a function of depth but not temperature in most biogeochemical models. This unique tradition or tactic inhibits useful discussion of climate change impacts, where specific and fundamental temperature-dependent terms are required. Tracer-based determinations of oxygen consumption rates in the deep sea are nearly universally reported as a function of depth in spite of their well-known microbial basis. In recent work, we have shown that a carefully determined profile of oxygen consumption rates in the Sargasso Sea can be well represented by a classical Arrhenius function with an activation energy of 86.5 kJ mol-1, leading to a Q10 of 3.63. This indicates that for 2°C warming, we will have a 29% increase in ocean oxygen consumption rates, and for 3°C warming, a 47% increase, potentially leading to large-scale ocean hypoxia should a sufficient amount of organic matter be available to microbes. Here, we show that the same principles apply to a worldwide collation of tracer-based oxygen consumption rate data and that some 95% of ocean oxygen consumption is driven by temperature, not depth, and thus will have a strong climate dependence. The Arrhenius/Eyring equations are no simple panacea and they require a non-equilibrium steady state to exist. Where transient events are in progress, this stricture is not obeyed and we show one such possible example. This article is part of the themed issue 'Ocean ventilation and deoxygenation in a warming world'.

Limit sets for the discrete spectrum of complex Jacobi matrices

International Nuclear Information System (INIS)

Golinskii, L B; Egorova, I E

2005-01-01

The discrete spectrum of complex Jacobi matrices that are compact perturbations of the discrete Laplacian is studied. The precise stabilization rate (in the sense of order) of the matrix elements ensuring the finiteness of the discrete spectrum is found. An example of a Jacobi matrix with discrete spectrum having a unique limit point is constructed. These results are discrete analogues of Pavlov's well-known results on Schroedinger operators with complex potential on a half-axis.

Rotational temperature measurement of NO gas using two-photon excitation spectrum

Science.gov (United States)

Ozaki, Tadao; Matsui, Yoshihiko; Ohsawa, Toshihiko

1981-04-01

The rotational temperature of nitric oxide gas has been measured by means of a single-beam two-photon excitation spectrum method using a pulsed continuously tunable dye laser. The nitric oxide gas was enclosed at about 40 Torr in a quartz cell which was put in an electric oven. The NO γ (0-0) band and R11+Q21 branches were used to obtain the two-photon excitation spectrum. The rotational temperatures were determined using the fact that molecules are distributed in the rotational levels according to the Boltzmann law. The temperature range was from room temperature to about 470 K. Observed temperatures were in good agreement with cell temperatures which were obtained by using a thermocouple.

Depth perception: the need to report ocean biogeochemical rates as functions of temperature, not depth.

Science.gov (United States)

Brewer, Peter G; Peltzer, Edward T

2017-09-13

For over 50 years, ocean scientists have oddly represented ocean oxygen consumption rates as a function of depth but not temperature in most biogeochemical models. This unique tradition or tactic inhibits useful discussion of climate change impacts, where specific and fundamental temperature-dependent terms are required. Tracer-based determinations of oxygen consumption rates in the deep sea are nearly universally reported as a function of depth in spite of their well-known microbial basis. In recent work, we have shown that a carefully determined profile of oxygen consumption rates in the Sargasso Sea can be well represented by a classical Arrhenius function with an activation energy of 86.5 kJ mol -1 , leading to a Q 10 of 3.63. This indicates that for 2°C warming, we will have a 29% increase in ocean oxygen consumption rates, and for 3°C warming, a 47% increase, potentially leading to large-scale ocean hypoxia should a sufficient amount of organic matter be available to microbes. Here, we show that the same principles apply to a worldwide collation of tracer-based oxygen consumption rate data and that some 95% of ocean oxygen consumption is driven by temperature, not depth, and thus will have a strong climate dependence. The Arrhenius/Eyring equations are no simple panacea and they require a non-equilibrium steady state to exist. Where transient events are in progress, this stricture is not obeyed and we show one such possible example.This article is part of the themed issue 'Ocean ventilation and deoxygenation in a warming world'. © 2017 The Author(s).

Temperature Limit of the Deep Subseafloor Biosphere in the Nankai Trough Subduction Zone off Cape Muroto (IODP T-Limit Expedition 370)

Science.gov (United States)

Morono, Y.; Hauer, V. B.; Inagaki, F.; Kubo, Y.; Maeda, L.; Scientists, E.

2017-12-01

Expedition 370 of the International Ocean Discovery Program (IODP) aimed to explore the limits of life in the deep subseafloor biosphere at a location where elevated heat flow lets temperature increase with sediment depth beyond the known maximum of microbial life ( 120°C) at 1.2 km below the seafloor. Such conditions are met in the protothrust zone of the Nankai Trough off Cape Muroto, Japan, where Site C0023 was established in the vicinity of ODP Sites 808 and 1174 at a water depth of 4776 m using the drilling vessel DV Chikyu. Hole C0023A was cored down to a total depth of 1180 meters below seafloor, offshore sampling and research was combined with simultaneous shore-based investigations at the Kochi Core Center (KCC), and long-term temperature observations were started (Heuer et al., 2017). The primary scientific objectives of Expedition 370 are (a) to detect and investigate the presence or absence of life and biological processes at the biotic-abiotic transition of the deep subseafloor with unprecedented analytical sensitivity and precision; (b) to comprehensively study the factors that control biomass, activity, and diversity of microbial communities; and (c) to elucidate if continuous or episodic flow of fluids containing thermogenic and/or geogenic nutrients and energy substrates support subseafloor microbial communities in the Nankai Trough accretionary complex (Hinrichs et al., 2016). This contribution will highlight the scientific approach of our field-work and preliminary expedition results by shipboard and shorebased activities. Hinrichs K-U, Inagaki F, Heuer VB, Kinoshita M, Morono Y, Kubo Y (2016) Expedition 370 Scientific Prospectus: T-Limit of the Deep Biosphere off Muroto (T-Limit). International Ocean Discovery Program. http://dx.doi.org/10.14379/iodp.sp.370.2016 Heuer VB, Inagaki F, Morono Y, Kubo Y, Maeda L, the Expedition 370 Scientists (2017) Expedition 370 Preliminary Report: Temperature Limit of the Deep Biosphere off Muroto. International

Temperature-controlled depth profiling in polymeric materials using cluster secondary ion mass spectrometry (SIMS)

Energy Technology Data Exchange (ETDEWEB)

Mahoney, Christine M. [National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8371, Gaithersburg, MD, 20899 (United States)]. E-mail: christine.mahoney@nist.gov; Fahey, Albert J. [National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8371, Gaithersburg, MD, 20899 (United States); Gillen, Greg [National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8371, Gaithersburg, MD, 20899 (United States); Xu Chang [National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8371, Gaithersburg, MD, 20899 (United States); Batteas, James D. [National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8371, Gaithersburg, MD, 20899 (United States)

2006-07-30

Secondary ion mass spectrometry (SIMS) employing an SF{sub 5} {sup +} polyatomic primary ion source was used to depth profile through poly(methylmethacrylate) (PMMA), poly(lactic acid) (PLA) and polystyrene (PS) thin films at a series of temperatures from -125 deg. C to 150 deg. C. It was found that for PMMA, reduced temperature analysis produced depth profiles with increased secondary ion stability and reduced interfacial widths as compared to analysis at ambient temperature. Atomic force microscopy (AFM) images indicated that this improvement in interfacial width may be related to a decrease in sputter-induced topography. Depth profiling at higher temperatures was typically correlated with increased sputter rates. However, the improvements in interfacial widths and overall secondary ion stability were not as prevalent as was observed at low temperature. For PLA, improvements in signal intensities were observed at low temperatures, yet there was no significant change in secondary ion stability, interface widths or sputter rates. High temperatures yielded a significant decrease in secondary ion stability of the resulting profiles. PS films showed rapid degradation of characteristic secondary ion signals under all temperatures examined.

Temperature of the Icelandic crust: Inferred from electrical conductivity, temperature surface gradient, and maximum depth of earthquakes

Science.gov (United States)

Björnsson, Axel

2008-02-01

Two different models of the structure of the Icelandic crust have been presented. One is the thin-crust model with a 10-15 km thick crust beneath the axial rift zones, with an intermediate layer of partially molten basalt at the base of the crust and on the top of an up-domed asthenosphere. The thick-crust model assumes a 40 km thick and relatively cold crust beneath central Iceland. The most important and crucial parameter to distinguish between these different models is the temperature distribution with depth. Three methods are used to estimate the temperature distribution with depth. First, the surface temperature gradient measured in shallow wells drilled outside geothermal areas. Second, the thickness of the seismogenic zone which is associated with a 750 °C isothermal surface. Third, the depth to a layer with high electrical conductivity which is associated with partially molten basalt with temperature around 1100 °C at the base of the crust. Combination of these data shows that the temperature gradient can be assumed to be nearly linear from the surface down to the base of the crust. These results are strongly in favour of the thin-crust model. The scattered deep seismic reflectors interpreted as Moho in the thick-crust model could be caused by phase transitions or reflections from melt pockets in the mantle.

Depth Dependent Relationships between Temperature and Ocean Heterotrophic Prokaryotic Production

KAUST Repository

Lønborg, Christian

2016-06-07

Marine prokaryotes play a key role in cycling of organic matter and nutrients in the ocean. Using a unique dataset (>14,500 samples), we applied a space-for-time substitution analysis to assess the temperature dependence of prokaryotic heterotrophic production (PHP) in epi- (0-200 m), meso- (201-1000 m) and bathypelagic waters (1001-4000 m) of the global ocean. Here, we show that the temperature dependence of PHP is fundamentally different between these major oceanic depth layers, with an estimated ecosystem-level activation energy (E) of 36 ± 7 kJ mol for the epipelagic, 72 ± 15 kJ mol for the mesopelagic and 274 ± 65 kJ mol for the bathypelagic realm. We suggest that the increasing temperature dependence with depth is related to the parallel vertical gradient in the proportion of recalcitrant organic compounds. These Ea predict an increased PHP of about 5, 12, and 55% in the epi-, meso-, and bathypelagic ocean, respectively, in response to a water temperature increase by 1°C. Hence, there is indication that a major thus far underestimated feedback mechanism exists between future bathypelagic ocean warming and heterotrophic prokaryotic activity.

Depth Dependent Relationships between Temperature and Ocean Heterotrophic Prokaryotic Production

KAUST Repository

Lø nborg, Christian; Cuevas, L. Antonio; Reinthaler, Thomas; Herndl, Gerhard J.; Gasol, Josep M.; Moran, Xose Anxelu G.; Bates, Nicholas R.; á lvarez-Salgado, Xosé A.

2016-01-01

Marine prokaryotes play a key role in cycling of organic matter and nutrients in the ocean. Using a unique dataset (>14,500 samples), we applied a space-for-time substitution analysis to assess the temperature dependence of prokaryotic heterotrophic production (PHP) in epi- (0-200 m), meso- (201-1000 m) and bathypelagic waters (1001-4000 m) of the global ocean. Here, we show that the temperature dependence of PHP is fundamentally different between these major oceanic depth layers, with an estimated ecosystem-level activation energy (E) of 36 ± 7 kJ mol for the epipelagic, 72 ± 15 kJ mol for the mesopelagic and 274 ± 65 kJ mol for the bathypelagic realm. We suggest that the increasing temperature dependence with depth is related to the parallel vertical gradient in the proportion of recalcitrant organic compounds. These Ea predict an increased PHP of about 5, 12, and 55% in the epi-, meso-, and bathypelagic ocean, respectively, in response to a water temperature increase by 1°C. Hence, there is indication that a major thus far underestimated feedback mechanism exists between future bathypelagic ocean warming and heterotrophic prokaryotic activity.

A mechanistic model of an upper bound on oceanic carbon export as a function of mixed layer depth and temperature

Directory of Open Access Journals (Sweden)

Z. Li

2017-11-01

Full Text Available Export production reflects the amount of organic matter transferred from the ocean surface to depth through biological processes. This export is in large part controlled by nutrient and light availability, which are conditioned by mixed layer depth (MLD. In this study, building on Sverdrup's critical depth hypothesis, we derive a mechanistic model of an upper bound on carbon export based on the metabolic balance between photosynthesis and respiration as a function of MLD and temperature. We find that the upper bound is a positively skewed bell-shaped function of MLD. Specifically, the upper bound increases with deepening mixed layers down to a critical depth, beyond which a long tail of decreasing carbon export is associated with increasing heterotrophic activity and decreasing light availability. We also show that in cold regions the upper bound on carbon export decreases with increasing temperature when mixed layers are deep, but increases with temperature when mixed layers are shallow. A meta-analysis shows that our model envelopes field estimates of carbon export from the mixed layer. When compared to satellite export production estimates, our model indicates that export production in some regions of the Southern Ocean, particularly the subantarctic zone, is likely limited by light for a significant portion of the growing season.

Theory of temperature dependent photoemission spectrum of heavy fermion semiconductors

International Nuclear Information System (INIS)

Riseborough, P.S.

1998-01-01

The heavy fermion semiconductors are a class of strongly correlated materials, that at high temperatures show properties similar to those of heavy fermion materials, but at low temperatures show a cross-over into a semi-conducting state. The low temperature insulating state is characterized by an anomalously small energy gap, varying between 10 and 100 K. The smallness of the gap is attributed to the result of a many-body renormalization, and is temperature dependent. The temperature dependence of the electronic spectral density of states is calculated, using the Anderson lattice model at half filling. The spectrum is calculated to second order in 1/N, where N is the degeneracy of the 'f' orbitals, using a slave boson technique. The system is an indirect gap semi-conductor, with an extremely temperature dependent electronic spectral density A(k, ω). The indirect gap is subject to a temperature dependent many-body renormalization, and leads to a sharp temperature dependent structure in the angle resolved photo-emission spectrum at the indirect threshold. The theoretical predictions are compared with experimental observations on FeSi. (Copyright (1998) World Scientific Publishing Co. Pte. Ltd)

Phonon Spectrum in Hydroxyapatite: Calculations and EPR Study at Low Temperatures

Science.gov (United States)

Biktagirov, Timur; Gafurov, Marat; Iskhakova, Kamila; Mamin, Georgy; Orlinskii, Sergei

2016-12-01

Density functional theory-based calculations within the framework of the plane-wave pseudopotential approach are carried out to define the phonon spectrum of hydroxyapatite Ca_{10}(PO4)6(OH)2 (HAp). It allows to describe the temperature dependence of the electronic spin-lattice relaxation time T_{1e} of the radiation-induced stable radical NO3^{2-} in HAp, which was measured in X-band (9 GHz, magnetic field strength of 0.34 T) in the temperature range T = (10-300) K. It is shown that the temperature behavior of T_{1e} at T> 20 K can be fitted via two-phonon Raman type processes with the Debye temperature Θ D ≈ 280 {K} evaluated from the phonon spectrum.

Capacity limits of spectrum-sharing systems over hyper-fading channels

KAUST Repository

Ekin, Sabit

2011-01-20

Cognitive radio (CR) with spectrum-sharing feature is a promising technique to address the spectrum under-utilization problem in dynamically changing environments. In this paper, the achievable capacity gain of spectrum-sharing systems over dynamic fading environments is studied. To perform a general analysis, a theoretical fading model called hyper-fading model that is suitable to the dynamic nature of CR channel is proposed. Closed-form expressions of probability density function (PDF) and cumulative density function (CDF) of the signal-to-noise ratio (SNR) for secondary users (SUs) in spectrum-sharing systems are derived. In addition, the capacity gains achievable with spectrum-sharing systems in high and low power regions are obtained. The effects of different fading figures, average fading powers, interference temperatures, peak powers of secondary transmitters, and numbers of SUs on the achievable capacity are investigated. The analytical and simulation results show that the fading figure of the channel between SUs and primary base-station (PBS), which describes the diversity of the channel, does not contribute significantly to the system performance gain. © 2011 John Wiley & Sons, Ltd.

Capacity limits of spectrum-sharing systems over hyper-fading channels

KAUST Repository

Ekin, Sabit; Yilmaz, Ferkan; Ç elebi, Hasari Burak; Qaraqe, Khalid A.; Alouini, Mohamed-Slim; Serpedin, Erchin

2011-01-01

Cognitive radio (CR) with spectrum-sharing feature is a promising technique to address the spectrum under-utilization problem in dynamically changing environments. In this paper, the achievable capacity gain of spectrum-sharing systems over dynamic fading environments is studied. To perform a general analysis, a theoretical fading model called hyper-fading model that is suitable to the dynamic nature of CR channel is proposed. Closed-form expressions of probability density function (PDF) and cumulative density function (CDF) of the signal-to-noise ratio (SNR) for secondary users (SUs) in spectrum-sharing systems are derived. In addition, the capacity gains achievable with spectrum-sharing systems in high and low power regions are obtained. The effects of different fading figures, average fading powers, interference temperatures, peak powers of secondary transmitters, and numbers of SUs on the achievable capacity are investigated. The analytical and simulation results show that the fading figure of the channel between SUs and primary base-station (PBS), which describes the diversity of the channel, does not contribute significantly to the system performance gain. © 2011 John Wiley & Sons, Ltd.

Trophic diversity, size and biomass spectrum of Bay of Bengal nematodes: A study case on depth and latitudinal patterns

Science.gov (United States)

Ansari, Kapuli Gani Mohamed Thameemul; Lyla, Somasundharanair; Khan, Syed Ajmal; Bhadury, Punyasloke

2017-09-01

Depth and latitudinal patterns of nematode functional attributes were investigated from 35 stations of Bay of Bengal (BoB) continental shelf. We aim to address whether depth and latitudinal variations can modify nematode community structure and their functional attributes (trophic diversity, size and biomass spectra). Global trend of depth and latitudinal related variations have also been noticed from BoB shelf in terms of nematode abundance and species richness, albeit heterogeneity patterns were encountered in functional attributes. Index of trophic diversity values revealed higher trophic diversity across the BoB shelf and suggested variety of food resource availability. However, downstream analysis of trophic status showed depth and latitude specific patterns but not reflected in terms of size and biomass spectrum. The peaks at different positions clearly visualized heterogeneity in distribution patterns for both size and biomass spectrum and also there was evidence of availability of diversified food resources. Nematode biomass spectra (NBS) constructed for nematode communities showed shift in peak biomass values towards lower to moderate size classes particularly in shallower depth but did not get reflected in latitudes. However, Chennai and Parangipettai transects demonstrated shift in peak biomass values towards higher biomass classes explaining the representation of higher nematode abundance. Our findings concluded that depth and latitudes are physical variables; they may not directly affect nematode community structure and functional attributes but they might influence the other factors such as food availability, sediment deposition and settlement rate. Our observations suggest that the local factors (seasonal character) of phytodetrital food flux can be very important for shaping the nematode community structure and success of nematode functional heterogeneity patterns across the Bay of Bengal shelf.

Laser measure of sea salinity, temperature and turbidity in depth

Science.gov (United States)

Hirschberg, J. G.; Wouters, A. W.; Byrne, J. D.

1974-01-01

A method is described in which a pulsed laser is used to probe the sea. Backscattered light is analyzed in time, intensity and wavelength. Tyndall, Raman and Brillouin scattering are used to obtain the backscatter turbidity, sound velocity, salinity, and the temperature as a function of depth.

Active silicon x-ray for measuring electron temperature

International Nuclear Information System (INIS)

Snider, R.T.

1994-07-01

Silicon diodes are commonly used for x-ray measurements in the soft x-ray region between a few hundred ev and 20 keV. Recent work by Cho has shown that the charge collecting region in an underbiased silicon detector is the depletion depth plus some contribution from a region near the depleted region due to charge-diffusion. The depletion depth can be fully characterized as a function of the applied bias voltage and is roughly proportional to the squart root of the bias voltage. We propose a technique to exploit this effect to use the silicon within the detector as an actively controlled x-ray filter. With reasonable silicon manufacturing methods, a silicon diode detector can be constructed in which the sensitivity of the collected charge to the impinging photon energy spectrum can be changed dynamically in the visible to above the 20 keV range. This type of detector could be used to measure the electron temperature in, for example, a tokamak plasma by sweeping the applied bias voltage during a plasma discharge. The detector samples different parts of the energy spectrum during the bias sweep, and the data collected contains enough information to determine the electron temperature. Benefits and limitations of this technique will be discussed along with comparisons to similar methods for measuring electron temperature and other applications of an active silicon x-ray filter

Radio frequency absorption and penetration depth limits in whole body MR imaging

International Nuclear Information System (INIS)

Roschmann, P.

1986-01-01

There is a continual debate over the ultimate limits to MR imaging at higher field strengths owing to the problems of increasing radio frequency (RF) power deposition and decreasing depth of B/sub 1/ field penetration in the patient. The authors present experimental results of RF absorption and penetration studies in humans for frequencies (f) of 30 to 220 MHz. Results were mostly derived from RF measurements of the effects of loading different types of head, body, and surface coils during imaging of volunteers and metal phantoms. Imaging at 2 T (85 MHz) does not exhibit significant RF problems; the local SAR amounts to 0.06 W/kg for a π-pulse of 1 msec and a TR of 1 sec. RF measurements of coil loading yield SAR -- f/sup 2.2/. The derived effective penetration depth drops from 17 cm at 85 MHz to 7 cm at 220 MHz. Head imaging appears possible up to 220 MHz (5 T). Body and surface coil imaging is subjected to increasing limitations in size or depth above 100 MHz

Temperature dependence of the experimental penetration depth of superconducting thin films

International Nuclear Information System (INIS)

Fink, H.J.; Gruenfeld, V.; Pastawski, H.

1982-01-01

Experimental magnetic field penetration depths delta(t,d,H) of the stable and superheated Meissner state were calculated as a function of temperature for various applied magnetic fields and various film thicknesses for two cases: (1) lambda(t)/d<< kappa→infinity and (2) kappa< or approx. =2lambda(t)/d (lambda is the Ginzburg-Landau penetration depth, d is the film thickness, kappa is the GL parameter). The results of the first case should be a useful tool for obtaining lambda(0) of amorphous superconducting thin films

[Emission spectrum temperature sensitivity of Mg4FGeO6 : mn induced by laser].

Science.gov (United States)

Wang, Sheng; Liu, Jing-Ru; Shao, Jun; Hu, Zhi-Yun; Tao, Bo; Huang, Mei-Sheng

2013-08-01

In order to develop a new sort of thermally sensitive phosphor coating, the emission spectrum thermally sensitivity of Mg4FGeO6 : Mn induced by laser was studied. The spectrum measurement system with heating function was set up, and the emission spectrum of Mg4FGeO6 : Mn at various temperatures were measured. Absorption spectrum was measured, and the mechanism of formation of the structure of double peak was analyzed with the perturbation theory of crystal lattice. The group of peaks around 630 nm is represented by the transitions 4F"2 to 4A2, whereas the group of peaks around 660 nm is due to the transitions 4F'2 to 4A2. The occupancy of both excited states 4F'2 and 4F"2 is in thermal equilibrium. Thus increasing temperature causes the intensity of the emission in the group around 630 nm to increase at the expense of the emission intensity of the group around 660 nm. The various spectral regions in emission differ with temperature, which could be used to support the intensity-ratio measurement method. The intensity-ratio change curve as a function of temperature was fitted, which shows that the range of temperature measurement is between room temperature and 800 K.

Modified Linnik microscopic interferometry for quantitative depth evaluation of diffraction-limited microgroove

Science.gov (United States)

Ye, Shiwei; Takahashi, Satoru; Michihata, Masaki; Takamasu, Kiyoshi

2018-05-01

The quality control of microgrooves is extremely crucial to ensure the performance and stability of microstructures and improve their fabrication efficiency. This paper introduces a novel optical inspection method and a modified Linnik microscopic interferometer measurement system to detect the depth of microgrooves with a width less than the diffraction limit. Using this optical method, the depth of diffraction-limited microgrooves can be related to the near-field optical phase difference, which cannot be practically observed but can be computed from practical far-field observations. Thus, a modified Linnik microscopic interferometer system based on three identical objective lenses and an optical path reversibility principle were developed. In addition, experiments for standard grating microgrooves on the silicon surface were carried out to demonstrate the feasibility and repeatability of the proposed method and developed measurement system.

Numerical evaluation and optimization of depth-oriented temperature measurements for the investigation of thermal influences on groundwater

Science.gov (United States)

Köhler, Mandy; Haendel, Falk; Epting, Jannis; Binder, Martin; Müller, Matthias; Huggenberger, Peter; Liedl, Rudolf

2015-04-01

Increasing groundwater temperatures have been observed in many urban areas such as London (UK), Tokyo (Japan) and also in Basel (Switzerland). Elevated groundwater temperatures are a result of different direct and indirect thermal impacts. Groundwater heat pumps, building structures located within the groundwater and district heating pipes, among others, can be addressed to direct impacts, whereas indirect impacts result from the change in climate in urban regions (i.e. reduced wind, diffuse heat sources). A better understanding of the thermal processes within the subsurface is urgently needed for decision makers as a basis for the selection of appropriate measures to reduce the ongoing increase of groundwater temperatures. However, often only limited temperature data is available that derives from measurements in conventional boreholes, which differ in construction and instrumental setup resulting in measurements that are often biased and not comparable. For three locations in the City of Basel models were implemented to study selected thermal processes and to investigate if heat-transport models can reproduce thermal measurements. Therefore, and to overcome the limitations of conventional borehole measurements, high-resolution depth-oriented temperature measurement systems have been introduced in the urban area of Basel. In total seven devices were installed with up to 16 sensors which are located in the unsaturated and saturated zone (0.5 to 1 m separation distance). Measurements were performed over a period of 4 years (ongoing) and provide sufficient data to set up and calibrate high-resolution local numerical heat transport models which allow studying selected local thermal processes. In a first setup two- and three-dimensional models were created to evaluate the impact of the atmosphere boundary on groundwater temperatures (see EGU Poster EGU2013-9230: Modelling Strategies for the Thermal Management of Shallow Rural and Urban Groundwater bodies). For Basel

Temperature profile and water depth data collected from TOWERS in the NE Atlantic (limit-180 W) from 06 June 1986 to 29 August 1986 (NODC Accession 8600378)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT from the TOWERS in the Northeast Atlantic Ocean, South China Sea, Philippine Sea, and...

On the temperature dependence of flammability limits of gases.

Science.gov (United States)

Kondo, Shigeo; Takizawa, Kenji; Takahashi, Akifumi; Tokuhashi, Kazuaki

2011-03-15

Flammability limits of several combustible gases were measured at temperatures from 5 to 100 °C in a 12-l spherical flask basically following ASHRAE method. The measurements were done for methane, propane, isobutane, ethylene, propylene, dimethyl ether, methyl formate, 1,1-difluoroethane, ammonia, and carbon monoxide. As the temperature rises, the lower flammability limits are gradually shifted down and the upper limits are shifted up. Both the limits shift almost linearly to temperature within the range examined. The linear temperature dependence of the lower flammability limits is explained well using a limiting flame temperature concept at the lower concentration limit (LFL)--'White's rule'. The geometric mean of the flammability limits has been found to be relatively constant for many compounds over the temperature range studied (5-100 °C). Based on this fact, the temperature dependence of the upper flammability limit (UFL) can be predicted reasonably using the temperature coefficient calculated for the LFL. However, some compounds such as ethylene and dimethyl ether, in particular, have a more complex temperature dependence. Copyright © 2011 Elsevier B.V. All rights reserved.

Temperature dependence of fluorescence decay time and emission spectrum of bismuth germanate

International Nuclear Information System (INIS)

Melcher, C.L.; Liberman, A.; Schweitzer, J.S.; Simonetti, J.

1985-01-01

Bismuth germanate has become an increasingly popular replacement for NaI(Tl) scintillators in recent years, mainly due to its higher detection efficiency. However, its scintillation efficiency and fluorescence decay time are strongly temperature dependent. Optimum performance of detector systems which employ BGO crystals depends on knowledge of the BGO pulse shape and intensity and its emission spectrum at the operating temperature of the detector. Measurements of these quantities are presented over the temperature range -47 0 C to +111 0 C. Although the emission spectrum shifts only slightly over this temperature range, the scintillation efficiency and fluorescence decay time are strongly temperature dependent. In addition to the usefulness of these data for optimizing detector design, the results imply that luminescence quenching in BGO cannot be characterized by a single thermal activation to a radiationless transition but that a more complex model is required to characterize the light output from BGO crystals

Capacity limits introduced by data fusion on cooperative spectrum sensing under correlated environments

DEFF Research Database (Denmark)

Pratas, Nuno; Marchetti, Nicola; Rodrigues, Antonio

2010-01-01

spectrum sensing scheme, by measuring the perceived capacity limits introduced by the use of data fusion on cooperative sensing schemes. The analysis is supported by evaluation metrics which account for the perceived capacity limits. The analysis is performed along the data fusion chain, comparing several...... scenarios encompassing different degree of environment correlation between the cluster nodes, number of cluster nodes and sensed channel occupation statistics. Through this study we motivate that to maximize the perceived capacity by the cooperative spectrum sensing, the use of data fusion needs...

Wind wave analysis in depth limited water using OCEANLYZ, A MATLAB toolbox

Science.gov (United States)

Karimpour, Arash; Chen, Qin

2017-09-01

There are a number of well established methods in the literature describing how to assess and analyze measured wind wave data. However, obtaining reliable results from these methods requires adequate knowledge on their behavior, strengths and weaknesses. A proper implementation of these methods requires a series of procedures including a pretreatment of the raw measurements, and adjustment and refinement of the processed data to provide quality assurance of the outcomes, otherwise it can lead to untrustworthy results. This paper discusses potential issues in these procedures, explains what parameters are influential for the outcomes and suggests practical solutions to avoid and minimize the errors in the wave results. The procedure of converting the water pressure data into the water surface elevation data, treating the high frequency data with a low signal-to-noise ratio, partitioning swell energy from wind sea, and estimating the peak wave frequency from the weighted integral of the wave power spectrum are described. Conversion and recovery of the data acquired by a pressure transducer, particularly in depth-limited water like estuaries and lakes, are explained in detail. To provide researchers with tools for a reliable estimation of wind wave parameters, the Ocean Wave Analyzing toolbox, OCEANLYZ, is introduced. The toolbox contains a number of MATLAB functions for estimation of the wave properties in time and frequency domains. The toolbox has been developed and examined during a number of the field study projects in Louisiana's estuaries.

Nondestructive strain depth profiling with high energy X-ray diffraction: System capabilities and limitations

Science.gov (United States)

Zhang, Zhan; Wendt, Scott; Cosentino, Nicholas; Bond, Leonard J.

2018-04-01

Limited by photon energy, and penetration capability, traditional X-ray diffraction (XRD) strain measurements are only capable of achieving a few microns depth due to the use of copper (Cu Kα1) or molybdenum (Mo Kα1) characteristic radiation. For deeper strain depth profiling, destructive methods are commonly necessary to access layers of interest by removing material. To investigate deeper depth profiles nondestructively, a laboratory bench-top high-energy X-ray diffraction (HEXRD) system was previously developed. This HEXRD method uses an industrial 320 kVp X-Ray tube and the Kα1 characteristic peak of tungsten, to produces a higher intensity X-ray beam which enables depth profiling measurement of lattice strain. An aluminum sample was investigated with deformation/load provided using a bending rig. It was shown that the HEXRD method is capable of strain depth profiling to 2.5 mm. The method was validated using an aluminum sample where both the HEXRD method and the traditional X-ray diffraction method gave data compared with that obtained using destructive etching layer removal, performed by a commercial provider. The results demonstrate comparable accuracy up to 0.8 mm depth. Nevertheless, higher attenuation capabilities in heavier metals limit the applications in other materials. Simulations predict that HEXRD works for steel and nickel in material up to 200 µm, but experiment results indicate that the HEXRD strain profile is not practical for steel and nickel material, and the measured diffraction signals are undetectable when compared to the noise.

Low-temperature thermal properties and features of the phonon spectrum of lutetium tetraboride

Energy Technology Data Exchange (ETDEWEB)

Novikov, V.V., E-mail: vvnovikov@mail.ru [Bryansk Petrovsky State University, 14 Bezhitskaya St., Bryansk 241037, Russia, (Russian Federation); Mitroshenkov, N.V., E-mail: weerm@yandex.ru [Bryansk Petrovsky State University, 14 Bezhitskaya St., Bryansk 241037, Russia, (Russian Federation); Matovnikov, A.V.; Avdashchenko, D.V. [Bryansk Petrovsky State University, 14 Bezhitskaya St., Bryansk 241037, Russia, (Russian Federation); Morozov, A.V. [Russian Timiryazev State Agrarian University, 49 Timiryazevskaya St., Moscow 127550 (Russian Federation); Pavlova, L.M.; Koltsov, V.B. [National Research University of Electronic Technology “MIET”, Moscow 124498 (Russian Federation)

2014-11-15

Highlights: • The coefficients of thermal expansion (α{sub ‖}, α{sub ⊥}) were measured for lutetium tetraboride. • The simplified Lutetium tetraboride phonon spectrum model is developed. • The Grüneisen parameters Γ, Γ{sub ‖}, Γ{sub ⊥} for lutetium tetraboride is calculated. • The anomalies of Γ{sub ‖}(T), Γ{sub ⊥}(T) at about 25 K are due to Einstein vibrations of boron sublattices. - Abstract: The coefficients of thermal expansion to the c axis (α{sub ‖}, α{sub ⊥}) were measured for lutetium tetraboride over the temperature range 4.2–300 K. The heat capacity data for lutetium tetraboride were used for the calculation of tetraboride phonon spectrum moments and also for the development of a simplified tetraboride spectrum model. The use of the heat capacity and thermal expansion data allowed the temperature changes of the Grüneisen parameters Γ, Γ{sub ‖}, Γ{sub ⊥} for tetraboride to be calculated. As a result of the approximation of Γ{sub ⊥}(T), Γ{sub ‖}(T) temperature dependencies in accordance with the chosen phonon spectrum model have been found: the anomalies of Γ{sub ⊥}(T), Γ{sub ‖}(T) are at about 25 K and then drop at lower temperatures due to the Einstein vibrations of boron sublattices.

Relationship between perceived limit-setting abilities, autism spectrum disorder severity, behaviour problems and parenting stress in mothers of children with autism spectrum disorder.

Science.gov (United States)

Reed, Phil; Howse, Jessie; Ho, Ben; Osborne, Lisa A

2017-11-01

Parenting stress in mothers of children with autism spectrum disorder (ASD) is high and impacts perceptions about parenting. This study examined the relationship between parenting stress and observer-perceived limit-setting ability. Participants' perceptions of other parents' limit-setting ability were assessed by showing participants video clips of parenting behaviours. Mothers of 93 children with autism spectrum disorder completed an online survey regarding the severity of their own child's autism spectrum disorder (Social Communication Questionnaire), their child's behaviour problems (Strengths and Difficulties Questionnaire) and their own levels of parenting stress (Questionnaire on Resources and Stress). They were shown five videos of other parents interacting with children with autism spectrum disorder and were asked to rate the limit-setting abilities observed in each video using the Parent-Child Relationship Inventory. Higher parenting stress negatively related to judgements about others' limit-setting skills. This mirrors the literature regarding the relationship between self-reported parenting stress and rating child behaviour more negatively. It suggests that stress negatively impacts a wide range of judgements and implies that caution may be required when interpreting the results of studies in which parenting skills are assessed by self-report.

Ambient temperature dependence on emission spectrum of InAs quantum dots

Energy Technology Data Exchange (ETDEWEB)

Ngo, C.Y.; Yoon, S.F. [School of Electrical and Electronic Engineering, Nanyang Technological University (Singapore); Chua, S.J. [Institute of Materials Research and Engineering, Faculty of Engineering (Singapore)

2009-04-15

Semiconductor superluminescent diodes (SLDs) are important broadband light source for fiber optic gyroscope and biomedical imaging. Quantum dots (QDs) have been proposed to be the best candidate for broadband light sources due to the inhomogeneous broadening of the gain spectrum as a result of the inherited size inhomogeneity of the self-assembled QD growth. In this work, the effect of ambient temperature (25-100 C) on the emission spectrum of InAs QDs with wideband emission was investigated. It was found that the full-width at half-maximum (FWHM) of the photoluminescence (PL) spectra remains more than 125 nm throughout the temperature range, and the redshift as function of temperature is approximately 0.27 meV/K. Activation energy of 270 meV is extracted from the Arrhenius plot and the PL quenching at high temperature is attributed to thermally induced carriers escaping out of the In{sub 0.15}Ga{sub 0.85}As strain-reducing layer. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Quantitative EEG in assessment of anaesthetic depth: comparative study of methodology

DEFF Research Database (Denmark)

Thomsen, C. E.; Prior, P. F.

1996-01-01

) and (4) a depth of anaesthesia monitor based on EEG pattern recognition (ADAM). Dose-response curves are presented for stepwise increases in stable end-tidal concentrations of each agent. Results indicated considerable inter-patient variability and the limitations of single EEG measures, particularly......Methodology for assessment of depth of anaesthesia based on analysis of the electroencephalogram (EEG) is controversial. Techniques range from display of single measures, for example median value of the frequency spectrum, to dedicated pattern recognition systems based on measures of several EEG...

Temperature Dependence of Apparent Respiratory Quotients and Oxygen Penetration Depth in Contrasting Lake Sediments

Science.gov (United States)

Sobek, Sebastian; Gudasz, Cristian; Koehler, Birgit; Tranvik, Lars J.; Bastviken, David; Morales-Pineda, María.

2017-11-01

Lake sediments constitute an important compartment in the carbon cycle of lakes, by burying carbon over geological timescales and by production and emission of greenhouse gases. The degradation of organic carbon (OC) in lake sediments is linked to both temperature and oxygen (O2), but the interactive nature of this regulation has not been studied in lake sediments in a quantitative way. We present the first systematic investigation of the effects of temperature on the apparent respiratory quotient (RQ, i.e., the molar ratio between carbon dioxide (CO2) production and O2 consumption) in two contrasting lake sediments. Laboratory incubations of sediment cores of a humic lake and an eutrophic lake across a 1-21°C temperature gradient over 157 days revealed that both CO2 production and O2 consumption were positively, exponentially, and similarly dependent on temperature. The apparent RQ differed significantly between the lake sediments (0.63 ± 0.26 and 0.99 ± 0.28 in the humic and the eutrophic lake, respectively; mean ± SD) and was significantly and positively related to temperature. The O2 penetration depth into the sediment varied by a factor of 2 over the 1-21°C temperature range and was significantly, negatively, and similarly related to temperature in both lake sediments. Accordingly, increasing temperature may influence the overall extent of OC degradation in lake sediments by limiting O2 supply to aerobic microbial respiration to the topmost sediment layer, resulting in a concomitant shift to less effective anaerobic degradation pathways. This suggests that temperature may represent a key controlling factor of the OC burial efficiency in lake sediments.

Demersal fish assemblages off southern New Zealand in relation to depth and temperature

Science.gov (United States)

Jacob, W.; McClatchie, S.; Probert, P. K.; Hurst, R. J.

1998-12-01

We examined the relationship between demersal fish assemblage and depth, temperature, latitude and longitude off southern New Zealand (46-54°S and 165-180°E) in water depths of 80-787 m. Catch weight data were analysed by two-way indicator analysis (TWIA), groupaverage agglomerative clustering (UPGMA) and Detrended Correspondence Analysis (DCA). The spatial pattern of demersal fish off southern New Zealand conforms to the concept of species groups or fish assemblages related to environmental gradients. Shallow-water assemblages were dominated by species from the families Gempylidae, Squalidae, Triakidae and Moridae, mainly represented by Thyrsites atun, Squalus acanthias, Galeorhinus australis, and Pseudophycis bachus. Deep water assemblages were dominated by Chimaeridae, Argentinidae, Merlucciidae and Macrouridae, mainly represented by Hydrolagus novaezelandiae, Argentina elongata, Macruronus novaezelandiae, and Lepidorhynchus denticulatus. Total catch weight was often dominated by Merlucciidae, Macrouridae and Gempylidae. Fish assemblages were related to discrete ranges of depth (300 m) and temperature (9.5°C), but the range of sediment types was too narrow to show any correlation.

AFSC/RACE/GAP/Nichol: Archival tag depth and temperature data from Atka mackerel

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Atka mackerel Pleurogrammus monopterygius were captured and tagged with depth and temperature recording devices (archival tags) on 23 July 2000 in Seguam Pass,...

Temperature profile and water depth data collected from HARRIOT LANE in the NW Atlantic (limit-40 W) from 20 February 1987 to 22 February 1987 (NODC Accession 8700096)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT from the HARRIOT LANE in the Northwest Atlantic Ocean and TOGA Area - Atlantic Ocean. Data...

Temperature profile and water depth data collected from HARRIOT LANE in the NW Atlantic (limit-40 W) from 29 December 1986 to 31 December 1986 (NODC Accession 8700074)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XTB casts in the NW Atlantic Ocean from the HARRIOT LANE. Data were collected from 29 December...

AFSC/RACE/GAP/Nichol: Archival tag depth and temperature data from Pacific cod

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Data from 250 recaptured (624 released) depth and temperature recording archival (data storage) tags attached to Pacific cod off Kodiak Island and in the eastern...

Primary system temperature limits and transient mitigation

Energy Technology Data Exchange (ETDEWEB)

Drucker, G.S.; Bost, D.S.

1978-10-03

Results of a study to determine the limiting temperature conditions in a large reactor system are presented. The study considers a sodium-cooled breeder reactor system having a loop-type primary system configuration. A temperature range of 930 to 1050/sup 0/F in reactor outlet temperature is covered. Significant findings were that the use of the materials for the 930/sup 0/F reference design, i.e., a core material of 20% cold-worked 316 stainless steel, a primary piping material of 316SS, and a steam generator material of unstabilized 2-1/4 Cr - 1 Mo resulted in limiting conditions in component performance at the higher temperatures. Means to circumvent these limits through the use of alternate materials, mitigation of thermal transients, and/or design changes are presented. The economic incentive to make some materials changes is also presented.

Ground Source Heat Supply in Moscow Oblast: Temperature Potential and Sustainable Depth of Heat Wells

Science.gov (United States)

Vasil'ev, G. P.; Gornov, V. F.; Dmitriev, A. N.; Kolesova, M. V.; Yurchenko, V. A.

2018-01-01

The paper is devoted to a problem of increasing the efficiency of low-potential geothermal heat in heat pump systems of residential buildings the Moscow oblast of Russia, including Moscow. Estimates of a natural geothermal potential in the Moscow oblast (based on climatological data for the period from 1982 to 2011) are presented and a "Typical climatic year of natural soil temperature variations for the geoclimatic conditions of the Moscow oblast, including the city of Moscow" is proposed. Numerical simulation of the influence of geothermal energy potential and the depth of heat wells on the efficiency of ground source heat pump systems for the heat supply of residential buildings is carried out. Analysis of the numerical simulation showed that the operation of a heat pump system in a house heating mode under the geoclimatic conditions of the Moscow oblast leads to a temperature drop of the heat-exchange medium circulating through heat wells to 5-6°C by the end of the first 10 years of operation, and the process stabilizes by the 15th year of operation, and further changes in the heat-exchange medium temperature do not any longer significantly affect the temperature of the heat-exchange medium in the heat well. In this case, the exact dependence of the heat-exchange medium temperature drop on the depth is not revealed. Data on the economically expedient heat well depth for the conditions of the Moscow oblast ensuring a net present value for the whole residential building life cycle are presented. It is found that the heat well depth of 60 m can be considered as an endpoint for the Moscow oblast, and a further heat well deepening is economically impractical.

Study of the muon spectrum at a depth 570 m.w.e. underground by means of the 100-ton scintillation detector

International Nuclear Information System (INIS)

Enikeev, R.I.; Zatsepin, G.T.; Korol'kova, E.V.; Kudryavtsev, V.A.; Mal'gin, A.S.; Ryazhskaya, O.G.; Khal'chukov, F.F.

1988-01-01

The experiment was carried out using the 100-ton apparatus at the Artemovsk Scientific Station of the Institute of Nuclear Research, USSR Academy of Sciences, located in a salt mine at a depth 570 m.w.e. underground. The spectrum of the energy release in the electromagnetic cascades which are generated by muons underground was measured. The electromagnetic and nuclear cascades were separated on the basis of the number of neutrons in these cascades. The spectrum of the energy release obtained is consistent with a spectrum of π and K mesons with γ/sub π//sub ,//sub K/ = 1.75 +- 0.08 for muon energies at sea level E 0 /sub μ/ >0.7 TeV. The experimental data recalculated to the vertical spectrum of muons at sea level agree with the results of other studies. Up to energies of about 100 TeV neither the spectrum of the primary cosmic rays nor the characteristics of the pA interaction undergo changes which could lead to an increase of γ/sub π//sub ,//sub K/ to a value exceeding 1.85

Tube temperature rise limits: Boiling considerations

Energy Technology Data Exchange (ETDEWEB)

Vanderwater, R.G.

1952-03-26

A revision of tube power limits based on boiling considerations was presented earlier. The limits were given on a basis of tube power versus header pressure. However, for convenience of operation, the limits have been converted from tube power to permissible water temperature rise. The permissible {triangle}t`s water are given in this document.

CFCI3 (CFC-11): UV Absorption Spectrum Temperature Dependence Measurements and the Impact on Atmospheric Lifetime and Uncertainty

Science.gov (United States)

Mcgillen, Max R.; Fleming, Eric L.; Jackman, Charles H.; Burkholder, James B.

2014-01-01

CFCl3 (CFC-11) is both an atmospheric ozone-depleting and potent greenhouse gas that is removed primarily via stratospheric UV photolysis. Uncertainty in the temperature dependence of its UV absorption spectrum is a significant contributing factor to the overall uncertainty in its global lifetime and, thus, model calculations of stratospheric ozone recovery and climate change. In this work, the CFC-11 UV absorption spectrum was measured over a range of wavelength (184.95 - 230 nm) and temperature (216 - 296 K). We report a spectrum temperature dependence that is less than currently recommended for use in atmospheric models. The impact on its atmospheric lifetime was quantified using a 2-D model and the spectrum parameterization developed in this work. The obtained global annually averaged lifetime was 58.1 +- 0.7 years (2 sigma uncertainty due solely to the spectrum uncertainty). The lifetime is slightly reduced and the uncertainty significantly reduced from that obtained using current spectrum recommendations

Phosphor-Doped Thermal Barrier Coatings Deposited by Air Plasma Spray for In-Depth Temperature Sensing

Directory of Open Access Journals (Sweden)

Di Peng

2016-09-01

Full Text Available Yttria-stabilized zirconia (YSZ-based thermal barrier coating (TBC has been integrated with thermographic phosphors through air plasma spray (APS for in-depth; non-contact temperature sensing. This coating consisted of a thin layer of Dy-doped YSZ (about 40 µm on the bottom and a regular YSZ layer with a thickness up to 300 µm on top. A measurement system has been established; which included a portable; low-cost diode laser (405 nm; a photo-multiplier tube (PMT and the related optics. Coating samples with different topcoat thickness were calibrated in a high-temperature furnace from room temperature to around 900 °C. The results convincingly showed that the current sensor and the measurement system was capable of in-depth temperature sensing over 800 °C with a YSZ top layer up to 300 µm. The topcoat thickness was found to have a strong effect on the luminescent signal level. Therefore; the measurement accuracy at high temperatures was reduced for samples with thick topcoats due to strong light attenuation. However; it seemed that the light transmissivity of YSZ topcoat increased with temperature; which would improve the sensor’s performance at high temperatures. The current sensor and the measurement technology have shown great potential in on-line monitoring of TBC interface temperature.

Effect of impurity scattering on the low temperature magnetic penetration depth of a nonlocal and nonlinear d-wave superconductor

International Nuclear Information System (INIS)

Yavary, H.

2006-01-01

The magnetic penetration depth of a quasi-two dimensional d-wave superconductor in the presence of nonlineary, nonlocality, and impurity effects is investigated by using Green's function method. It is shown that a d-wave superconductor would inevitably avoid the violation of the Nernst theorem by creating a T 2 term in its penetration depth through a competition of nonlinear, nonlocal, and impurity effects and this system may be stable at low temperatures. I also show that in the impure sample at low temperatures, T < T * ∝ γ the impurity effect determines the temperature dependence of the penetration depth, i.e., nonlocal and nonlinear effects are completely masked by impurities

The Hengill geothermal area, Iceland: Variation of temperature gradients deduced from the maximum depth of seismogenesis

Science.gov (United States)

Foulger, G. R.

1995-04-01

Given a uniform lithology and strain rate and a full seismic data set, the maximum depth of earthquakes may be viewed to a first order as an isotherm. These conditions are approached at the Hengill geothermal area S. Iceland, a dominantly basaltic area. The likely strain rate calculated from thermal and tectonic considerations is 10 -15 s -1, and temperature measurements from four drill sites within the area indicate average, near-surface geothermal gradients of up to 150 °C km -1 throughout the upper 2 km. The temperature at which seismic failure ceases for the strain rates likely at the Hengill geothermal area is determined by analogy with oceanic crust, and is about 650 ± 50 °C. The topographies of the top and bottom of the seismogenic layer were mapped using 617 earthquakes located highly accurately by performing a simultaneous inversion for three-dimensional structure and hypocentral parameters. The thickness of the seismogenic layer is roughly constant and about 3 km. A shallow, aseismic, low-velocity volume within the spreading plate boundary that crosses the area occurs above the top of the seismogenic layer and is interpreted as an isolated body of partial melt. The base of the seismogenic layer has a maximum depth of about 6.5 km beneath the spreading axis and deepens to about 7 km beneath a transform zone in the south of the area. Beneath the high-temperature part of the geothermal area, the maximum depth of earthquakes may be as shallow as 4 km. The geothermal gradient below drilling depths in various parts of the area ranges from 84 ± 9 °Ckm -1 within the low-temperature geothermal area of the transform zone to 138 ± 15 °Ckm -1 below the centre of the high-temperature geothermal area. Shallow maximum depths of earthquakes and therefore high average geothermal gradients tend to correlate with the intensity of the geothermal area and not with the location of the currently active spreading axis.

Influence of Annealing on the Depth Microstructure of the Shot Peened Duplex Stainless Steel at Elevated Temperature

Science.gov (United States)

Feng, Qiang; She, Jia; Xiang, Yong; Wu, Xianyun; Wang, Chengxi; Jiang, Chuanhai

The depth profiles of residual stresses and lattice parameters in the surface layers of shot peened duplex stainless steel at elevated temperature were investigated utilizing X-ray diffraction analysis. At each deformation depth, residual stress distributions in both ferrite and austenite were studied by X-ray diffraction stress analysis which is performed on the basis of the sin2ψ method and the lattice parameters were explored by Rietveld method. The results reveal that difference changes of depth residual compressive stress profiles between ferrite and austenite under the same annealing condition are resulted from the diverse coefficient of thermal expansion, dislocation density, etc. for different phases in duplex stainless steel. The relaxations of depth residual stresses in austenite are more obvious than those in ferrite. The lattice parameters decrease in the surface layer with the extending of annealing time, however, they increase along the depth after annealing for 16min. The change of the depth lattice parameters can be ascribed to both thermal expansion and the relaxation of residual stress. The different changes of microstructure at elevated temperature between ferrite and austenite are discussed.

System Capacity Limits Introduced by Data Fusion on Cooperative Spectrum Sensing under Correlated Environments

DEFF Research Database (Denmark)

Pratas, Nuno; Marchetti, Nicola; Prasad, Neeli R.

2010-01-01

on cooperative sensing schemes. The analysis is supported by evaluation metrics which accounts for the perceived capacity limits. The analysis is performed along the data fusion chain, comparing several scenarios encompassing different degrees of environment correlation between the cluster nodes, number......Spectrum sensing, the cornerstone of the Cognitive Radio paradigm, has been the focus of intensive research, from which the main conclusion was that its performance can be greatly enhanced through the use of cooperative sensing schemes. Nevertheless, if a proper design of the cooperative scheme...... is not followed, then the use of cooperative schemes will introduce some limitations in the network perceived capacity. In this paper, we analyze the performance of a cooperative spectrum sensing scheme based on Data Fusion, by measuring the perceived capacity limits introduced by the use of Data Fusion...

[Geothermal system temperature-depth database and model for data analysis]. 5. quarterly technical progress report

Energy Technology Data Exchange (ETDEWEB)

Blackwell, D.D.

1998-04-25

During this first quarter of the second year of the contract activity has involved several different tasks. The author has continued to work on three tasks most intensively during this quarter: the task of implementing the data base for geothermal system temperature-depth, the maintenance of the WWW site with the heat flow and gradient data base, and finally the development of a modeling capability for analysis of the geothermal system exploration data. The author has completed the task of developing a data base template for geothermal system temperature-depth data that can be used in conjunction with the regional data base that he had already developed and is now implementing it. Progress is described.

The chiral anomaly of quantum chromodynamics at high temperatures. Lattice investigation of the overlap Dirac spectrum

International Nuclear Information System (INIS)

Dick, Viktor

2016-04-01

In this work, the spectrum of the overlap Dirac operator has been computed and analyzed on configurations that had been created using highly improved staggered quarks. Although the overlap operator is expensive to compute, it has the advantage that it fully implements chiral symmetry in the same way as the continuum QCD Dirac operator even at finite lattice spacings. This opened the possibility to investigate chiral aspects of QCD and, in particular, the question if the axial anomaly is suppressed at the chiral transition temperature T c . The obtained results indicate that the axial anomaly is still present at T c and even at 1.5 T c as evidenced by a splitting in the integrated pion and delta susceptibilities. The spectrum shows a peak in the near-zero region consisting of zero modes and pairs of near-zero modes. The breaking of the axial symmetry was identified as being caused by these infrared modes. It was discussed how this infrared contribution might change in the thermodynamic, continuum, and chiral limits. The obtained data supports the expectation that the peak becomes narrower with decreasing quark masses, resulting in a Dirac-delta peak in the chiral limit. The area under the peak was found to decrease with decreasing lattice spacing, so in order to resolve how much of it survives the continuum limit further investigations are needed, in particular ones where already for the generation of gauge configurations chiral fermions are used. The infrared modes were investigated and found to be highly localized, supporting the picture of QCD at high temperatures as a dilute instanton gas. The instantons were found to have an average size of 0.239(4) fm and a density of 0.154(5) fm -4 at 1.5 T c . Near-zero modes were found to be induced by instanton-anti-instanton molecules, which are weakly bound. At temperatures closer to T c , this picture becomes more complicated but these features sometimes still can be recognized. In conclusion, in QCD at temperatures

Extending the fundamental imaging-depth limit of multi-photon microscopy by imaging with photo-activatable fluorophores.

Science.gov (United States)

Chen, Zhixing; Wei, Lu; Zhu, Xinxin; Min, Wei

2012-08-13

It is highly desirable to be able to optically probe biological activities deep inside live organisms. By employing a spatially confined excitation via a nonlinear transition, multiphoton fluorescence microscopy has become indispensable for imaging scattering samples. However, as the incident laser power drops exponentially with imaging depth due to scattering loss, the out-of-focus fluorescence eventually overwhelms the in-focal signal. The resulting loss of imaging contrast defines a fundamental imaging-depth limit, which cannot be overcome by increasing excitation intensity. Herein we propose to significantly extend this depth limit by multiphoton activation and imaging (MPAI) of photo-activatable fluorophores. The imaging contrast is drastically improved due to the created disparity of bright-dark quantum states in space. We demonstrate this new principle by both analytical theory and experiments on tissue phantoms labeled with synthetic caged fluorescein dye or genetically encodable photoactivatable GFP.

Temperature profile and water depth data collected from RATHBURNE in the NW Pacific (limit-180 W) and other areas from 02 February 1986 to 28 February 1986 (NODC Accession 8600093)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT from the RATHBURNE in the Northwest Pacific Ocean and other areas. Data were collected from...

Effect of modulation depth, frequency, and intermittence on wind turbine noise annoyance

DEFF Research Database (Denmark)

Ioannidou, Christina; Santurette, Sébastien; Jeong, Cheol-Ho

2016-01-01

, while determined from real on-site recordings, could be varied systematically. Listening tests with both original and synthesized stimuli showed that a reduction in mean AM depth across the spectrum led to a significant decrease in annoyance. When the spectrotemporal characteristics of the original far......-field stimuli and the temporal AM variations were taken into account, the effect of AM frequency remained limited and the presence of intermittent OAM periods did not affect annoyance. These findings suggest that, at a given overall level, the AM depth of NAM periods is the most crucial AM parameter for WTN...

Energy spectrum control for modulated proton beams

International Nuclear Information System (INIS)

Hsi, Wen C.; Moyers, Michael F.; Nichiporov, Dmitri; Anferov, Vladimir; Wolanski, Mark; Allgower, Chris E.; Farr, Jonathan B.; Mascia, Anthony E.; Schreuder, Andries N.

2009-01-01

In proton therapy delivered with range modulated beams, the energy spectrum of protons entering the delivery nozzle can affect the dose uniformity within the target region and the dose gradient around its periphery. For a cyclotron with a fixed extraction energy, a rangeshifter is used to change the energy but this produces increasing energy spreads for decreasing energies. This study investigated the magnitude of the effects of different energy spreads on dose uniformity and distal edge dose gradient and determined the limits for controlling the incident spectrum. A multilayer Faraday cup (MLFC) was calibrated against depth dose curves measured in water for nonmodulated beams with various incident spectra. Depth dose curves were measured in a water phantom and in a multilayer ionization chamber detector for modulated beams using different incident energy spreads. Some nozzle entrance energy spectra can produce unacceptable dose nonuniformities of up to ±21% over the modulated region. For modulated beams and small beam ranges, the width of the distal penumbra can vary by a factor of 2.5. When the energy spread was controlled within the defined limits, the dose nonuniformity was less than ±3%. To facilitate understanding of the results, the data were compared to the measured and Monte Carlo calculated data from a variable extraction energy synchrotron which has a narrow spectrum for all energies. Dose uniformity is only maintained within prescription limits when the energy spread is controlled. At low energies, a large spread can be beneficial for extending the energy range at which a single range modulator device can be used. An MLFC can be used as part of a feedback to provide specified energy spreads for different energies.

Evolution of spin excitations in a gapped antiferromagnet from the quantum to the high-temperature limit

DEFF Research Database (Denmark)

Kenzelmann, M.; Cowley, R.A.; Buyers, W.J.L.

2002-01-01

We have mapped from the quantum to the classical limit the spin excitation spectrum of the antiferromagnetic spin-1 Heisenberg chain system CsNiCl3 in its paramagnetic phase from T=5 to 200 K. Neutron scattering shows that the excitations are resonant and dispersive up to at least T=70 Ksimilar...... is in agreement with quantum Monte Carlo calculations for the spin-1 chain. xi is also consistent with the single mode approximation, suggesting that the excitations are short-lived single particle excitations. Below T=12 K where three-dimensional spin correlations are important, xi is shorter than predicted...... and the experiment is not consistent with the random phase approximation for coupled quantum chains. At T=200 K, the structure factor and second energy moment of the excitation spectrum are in excellent agreement with the high-temperature series expansion....

Planck intermediate results LI. Features in the cosmic microwave background temperature power spectrum and shifts in cosmological parameters

DEFF Research Database (Denmark)

Aghanim, N.; Akrami, Y.; Ashdown, M.

2017-01-01

The six parameters of the standard ΛCDM model have best-fit values derived from the Planck temperature power spectrum that are shifted somewhat from the best-fit values derived from WMAP data. These shifts are driven by features in the Planck temperature power spectrum at angular scales that had ...

Missing depth cues in virtual reality limit performance and quality of three dimensional reaching movements.

Science.gov (United States)

Gerig, Nicolas; Mayo, Johnathan; Baur, Kilian; Wittmann, Frieder; Riener, Robert; Wolf, Peter

2018-01-01

Goal-directed reaching for real-world objects by humans is enabled through visual depth cues. In virtual environments, the number and quality of available visual depth cues is limited, which may affect reaching performance and quality of reaching movements. We assessed three-dimensional reaching movements in five experimental groups each with ten healthy volunteers. Three groups used a two-dimensional computer screen and two groups used a head-mounted display. The first screen group received the typically recreated visual depth cues, such as aerial and linear perspective, occlusion, shadows, and texture gradients. The second screen group received an abstract minimal rendering lacking those. The third screen group received the cues of the first screen group and absolute depth cues enabled by retinal image size of a known object, which realized with visual renderings of the handheld device and a ghost handheld at the target location. The two head-mounted display groups received the same virtually recreated visual depth cues as the second or the third screen group respectively. Additionally, they could rely on stereopsis and motion parallax due to head-movements. All groups using the screen performed significantly worse than both groups using the head-mounted display in terms of completion time normalized by the straight-line distance to the target. Both groups using the head-mounted display achieved the optimal minimum in number of speed peaks and in hand path ratio, indicating that our subjects performed natural movements when using a head-mounted display. Virtually recreated visual depth cues had a minor impact on reaching performance. Only the screen group with rendered handhelds could outperform the other screen groups. Thus, if reaching performance in virtual environments is in the main scope of a study, we suggest applying a head-mounted display. Otherwise, when two-dimensional screens are used, achievable performance is likely limited by the reduced depth

NF3: UV Absorption Spectrum Temperature Dependence and the Atmospheric and Climate Forcing Implications

Science.gov (United States)

Papadimitriou, Vassileios C.; McGillen, Max R.; Fleming, Eric L.; Jackman, Charles H.; Burkholder, James B.

2013-01-01

Nitrogen trifluoride (NF3) is an atmospherically persistent greenhouse gas that is primarily removed by UV photolysis and reaction with O((sup 1)D) atoms. In this work, the NF3 gas-phase UV absorption spectrum, sigma(delta,T), was measured at 16 wavelengths between 184.95 and 250 nm at temperatures between 212 and 296 K. A significant spectrum temperature dependence was observed in the wavelength region most relevant to atmospheric photolysis (200-220 nm) with a decrease in sigma(210 nm,T) of approximately 45 percent between 296 and 212 K. Atmospheric photolysis rates and global annually averaged lifetimes of NF3 were calculated using the Goddard Space Flight Center 2-D model and the sigma(delta,T) parameterization developed in this work. Including the UV absorption spectrum temperature dependence increased the stratospheric photolysis lifetime from 610 to 762 years and the total global lifetime from 484 to 585 years; the NF3 global warming potentials on the 20-, 100-, and 500-year time horizons increased less than 0.3, 1.1, and 6.5 percent to 13,300, 17,700, and 19,700, respectively.

The Hagedorn spectrum, nuclear level densities and first order phase transitions

International Nuclear Information System (INIS)

Moretto, Luciano G.; Larsen, A. C.; Guttormsen, M.; Siem, S.

2015-01-01

An exponential mass spectrum, like the Hagedorn spectrum, with slope 1/T H was interpreted as fixing an upper limiting temperature T H that the system can achieve. However, thermodynamically, such spectrum indicates a 1 st order phase transition at a fixed temperature T H . A much lower energy example is the log linear level nuclear density below the neutron binding energy that prevails throughout the nuclear chart. We show that, for non-magic nuclei, such linearity implies a 1 st order phase transition from the pairing superfluid to an ideal gas of quasi particles

Relationship between Perceived Limit-Setting Abilities, Autism Spectrum Disorder Severity, Behaviour Problems and Parenting Stress in Mothers of Children with Autism Spectrum Disorder

Science.gov (United States)

Reed, Phil; Howse, Jessie; Ho, Ben; Osborne, Lisa A.

2017-01-01

Parenting stress in mothers of children with autism spectrum disorder (ASD) is high and impacts perceptions about parenting. This study examined the relationship between parenting stress and observer-perceived limit-setting ability. Participants' perceptions of other parents' limit-setting ability were assessed by showing participants video clips…

Photonic crystal fiber coil sensor for water-depth sensing

Science.gov (United States)

Fan, Chen-Feng; Yu, Chin-Ping

2013-05-01

We fabricate a PCF coil sensor for water-depth sensing by winding a PCF on a plastic straw. Due to the bending-induced birefringence along the PCF, we can observe clear interference pattern in the output spectrum by placing the PCF coil into a Sagnac fiber loop. As we horizontally immerse the fabricated PCF coil into water, a nonlinear relationship between the water depth and the wavelength shift can be obtained. We have also measured the interference spectrum by vertically immersing the PCF coil into water. We can observe a linear relationship between the water depth and the wavelength shift, and the measured water-depth sensitivity for vertical immersion is -1.17 nm/mm.

Low temperature plasma near a tokamak reactor limiter

International Nuclear Information System (INIS)

Braams, B.J.; Singer, C.E.

1985-01-01

Analytic and two-dimensional computational solutions for the plasma parameters near a toroidally symmetric limiter are illustrated for the projected parameters of a Tokamak Fusion Core Experiment (TFCX). The temperature near the limiter plate is below 20 eV, except when the density 10 cm inside the limiter contact is 8 x 10 13 cm -3 or less and the thermal diffusivity in the edge region is 2 x 10 4 cm 2 /s or less. Extrapolation of recent experimental data suggests that neither of these conditions is likely to be met near ignition in TFCX, so a low plasma temperature near the limiter should be considered a likely possibility

[Investigation on the gas temperature of a plasma jet at atmospheric pressure by emission spectrum].

Science.gov (United States)

Li, Xue-chen; Yuan, Ning; Jia, Peng-ying; Niu, Dong-ying

2010-11-01

A plasma jet of a dielectric barrier discharge in coaxial electrode was used to produce plasma plume in atmospheric pressure argon. Spatially and temporally resolved measurement was carried out by photomultiplier tubes. The light emission signals both from the dielectric barrier discharge and from the plasma plume were analyzed. Furthermore, emission spectrum from the plasma plume was collected by high-resolution optical spectrometer. The emission spectra of OH (A 2sigma + --> X2 II, 307.7-308.9 nm) and the first negative band of N2+ (B2 sigma u+ --> X2 IIg+, 390-391.6 nm) were used to estimate the rotational temperature of the plasma plume by fitting the experimental spectra to the simulated spectra. The rotational temperature obtained is about 443 K by fitting the emission spectrum from the OH, and that from the first negative band of N2+ is about 450 K. The rotational temperatures obtained by the two method are consistent within 5% error band. The gas temperature of the plasma plume at atmospheric pressure was obtained because rotational temperature equals to gas temperature approximately in gas discharge at atmospheric pressure. Results show that gas temperature increases with increasing the applied voltage.

Distribution in depth of quasars

International Nuclear Information System (INIS)

Schmidt, M.; Green, R.F.

1980-01-01

The authors discuss the distribution in depth of different kinds of quasars: quasi-stellar radio sources with steep radio spectrum, those with flat radio spectrum, and optically selected quasars. All exhibit an increase of space density with distance to a different degree. The optically selected quasars, in particular, show a steep increase of surface density with magnitude. The steepness of the increase is inconsistent with a uniform distribution of quasars in the local hypothesis. In the cosmological hypothesis the co-moving space density of optically selected quasars increases by a factor of 100,000 to a redshift of 2, and by factors of 1000 and 10 for steep-spectrum and flat-spectrum radio quasars, respectively. (Auth.)

Joint opportunistic beam and spectrum selection schemes for spectrum sharing systems with limited feedback

KAUST Repository

Sayed, Mostafa M.; Abdallah, Mohamed M.; Qaraqe, Khalid A.; Tourki, Kamel; Alouini, Mohamed-Slim

2014-01-01

Spectrum sharing systems have been introduced to alleviate the problem of spectrum scarcity by allowing an unlicensed secondary user (SU) to share the spectrum with a licensed primary user (PU) under acceptable interference levels to the primary

The Hagedorn spectrum, nuclear level densities and first order phase transitions

Energy Technology Data Exchange (ETDEWEB)

Moretto, Luciano G., E-mail: lgmoretto@lbl.gov [Department of Chemistry, University of California, Berkeley, Lawrence Berkeley National Laboratory 1 Cyclotron Road, Berkeley, CA 94720 (United States); Larsen, A. C.; Guttormsen, M.; Siem, S. [Department of Physics, University of Oslo, N-0316 Oslo (Norway)

2015-10-15

An exponential mass spectrum, like the Hagedorn spectrum, with slope 1/T{sub H} was interpreted as fixing an upper limiting temperature T{sub H} that the system can achieve. However, thermodynamically, such spectrum indicates a 1{sup st} order phase transition at a fixed temperature T{sub H}. A much lower energy example is the log linear level nuclear density below the neutron binding energy that prevails throughout the nuclear chart. We show that, for non-magic nuclei, such linearity implies a 1{sup st} order phase transition from the pairing superfluid to an ideal gas of quasi particles.

Universality of the high-temperature viscosity limit of silicate liquids

DEFF Research Database (Denmark)

Zheng, Qiuju; Mauro, John C.; Ellison, Adam J.

2011-01-01

We investigate the high-temperature limit of liquid viscosity by analyzing measured viscosity curves for 946 silicate liquids and 31 other liquids including metallic, molecular, and ionic systems. Our results show no systematic dependence of the high-temperature viscosity limit on chemical...... composition for the studied liquids. Based on theMauro-Yue-Ellison-Gupta-Allan (MYEGA) model of liquid viscosity, the high-temperature viscosity limit of silicate liquids is 10−2.93 Pa·s. Having established this value, there are only two independent parameters governing the viscosity-temperature relation...

Investigation of the shallow depth explosions

International Nuclear Information System (INIS)

Kamegai, M.

1976-01-01

An investigation of the nuclear explosions at shallow depth is made. A combination of an explosion code and an effects code proves to be an excellent tool for this study. A numerical simulation of ''Johnie Boy'' shows that the energy coupling to the air takes place in two stages; first by a rising mound, and then by a vented source. The thermal effects are examined for a 1 kt source at three depths of burial. The ''mushroom effect'' leaves a hot radiative plasma in the upper level and cold materials in the lower region of the debris. The temperature and the energy density of the debris can give an upper limit on the thermal output

Response approach to the squeezed-limit bispectrum: application to the correlation of quasar and Lyman-α forest power spectrum

Energy Technology Data Exchange (ETDEWEB)

Chiang, Chi-Ting [C.N. Yang Institute for Theoretical Physics, Stony Brook University, Stony Brook, NY 11794 (United States); Cieplak, Agnieszka M.; Slosar, Anže [Brookhaven National Laboratory, Blgd 510, Upton, NY 11375 (United States); Schmidt, Fabian, E-mail: chi-ting.chiang@stonybrook.edu, E-mail: acieplak@bnl.gov, E-mail: fabians@mpa-garching.mpg.de, E-mail: anze@bnl.gov [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching (Germany)

2017-06-01

The squeezed-limit bispectrum, which is generated by nonlinear gravitational evolution as well as inflationary physics, measures the correlation of three wavenumbers, in the configuration where one wavenumber is much smaller than the other two. Since the squeezed-limit bispectrum encodes the impact of a large-scale fluctuation on the small-scale power spectrum, it can be understood as how the small-scale power spectrum ''responds'' to the large-scale fluctuation. Viewed in this way, the squeezed-limit bispectrum can be calculated using the response approach even in the cases which do not submit to perturbative treatment. To illustrate this point, we apply this approach to the cross-correlation between the large-scale quasar density field and small-scale Lyman-α forest flux power spectrum. In particular, using separate universe simulations which implement changes in the large-scale density, velocity gradient, and primordial power spectrum amplitude, we measure how the Lyman-α forest flux power spectrum responds to the local, long-wavelength quasar overdensity, and equivalently their squeezed-limit bispectrum. We perform a Fisher forecast for the ability of future experiments to constrain local non-Gaussianity using the bispectrum of quasars and the Lyman-α forest. Combining with quasar and Lyman-α forest power spectra to constrain the biases, we find that for DESI the expected 1−σ constraint is err[ f {sub NL}]∼60. Ability for DESI to measure f {sub NL} through this channel is limited primarily by the aliasing and instrumental noise of the Lyman-α forest flux power spectrum. The combination of response approach and separate universe simulations provides a novel technique to explore the constraints from the squeezed-limit bispectrum between different observables.

Temperature sensitivity differences with depth and season between carbon, nitrogen, and phosphorus cycling enzyme activities in an ombrotrophic peatland system

Science.gov (United States)

Steinweg, J. M.; Kostka, J. E.; Hanson, P. J.; Schadt, C. W.

2017-12-01

Northern peatlands have large amounts of soil organic matter due to reduced decomposition. Breakdown of organic matter is initially mediated by extracellular enzymes, the activity of which may be controlled by temperature, moisture, and substrate availability, all of which vary seasonally throughout the year and with depth. In typical soils the majority of the microbial biomass and decomposition occurs within the top 30cm due to reduced organic matter inputs in the subsurface however peatlands by their very nature contain large amounts of organic matter throughout their depth profile. We hypothesized that potential enzyme activity would be greatest at the surface of the peat due to a larger microbial biomass compared to 40cm and 175cm below the surface and that temperature sensitivity would be greatest at the surface during winter but lowest during the summer due to high temperatures and enzyme efficiency. Peat samples were collected in February, July, and August 2012 from the DOE Spruce and Peatland Responses Under Climatic and Environmental Change project at Marcell Experimental Forest S1 bog. We measured potential activity of hydrolytic enzymes involved in three different nutrient cycles: beta-glucosidase (carbon), leucine amino peptidase (nitrogen), and phosphatase (phosphorus) at 15 temperature points ranging from 3°C to 65°C. Enzyme activity decreased with depth as expected but there was no concurrent change in activation energy (Ea). The reduction in enzyme activity with depth indicates a smaller pool which coincided with a decreased microbial biomass. Differences in enzyme activity with depth also mirrored the changes in peat composition from the acrotelm to the catotelm. Season did play a role in temperature sensitivity with Ea of β-glucosidase and phosphatase being the lowest in August as expected but leucine amino peptidase (a nitrogen acquiring enzyme) Ea was not influenced by season. As temperatures rise, especially in winter months, enzymatic

Transmission Level High Temperature Superconducting Fault Current Limiter

Energy Technology Data Exchange (ETDEWEB)

Stewart, Gary [SuperPower, Inc., Schenectady, NY (United States)

2016-10-05

The primary objective of this project was to demonstrate the feasibility and reliability of utilizing high-temperature superconducting (HTS) materials in a Transmission Level Superconducting Fault Current Limiter (SFCL) application. During the project, the type of high-temperature superconducting material used evolved from 1^st generation (1G) BSCCO-2212 melt cast bulk high-temperature superconductors to 2^nd generation (2G) YBCO-based high-temperature superconducting tape. The SFCL employed SuperPower's “Matrix” technology, that offers modular features to enable scale up to transmission voltage levels. The SFCL consists of individual modules that contain elements and parallel inductors that assist in carrying the current during the fault. A number of these modules are arranged in an m x n array to form the current-limiting matrix.

Northeast Cooperative Research Study Fleet (SF) Program Combined GPS, Temperature/Depth, and Effort Fishery Dependent Data

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, depth(TD), GPS and haul by haul effort and catch data are collected during normal fishing activity of commercial fishing vessels participating in the...

Eddy-current inversion in the thin-skin limit: Determination of depth and opening for a long crack

Science.gov (United States)

Burke, S. K.

1994-09-01

A method for crack size determination using eddy-current nondestructive evaluation is presented for the case of a plate containing an infinitely long crack of uniform depth and uniform crack opening. The approach is based on the approximate solution to Maxwell's equations for nonmagnetic conductors in the limit of small skin depth and relies on least-squares polynomial fits to a normalized coil impedance function as a function of skin depth. The method is straightforward to implement and is relatively insensitive to both systematic and random errors. The procedure requires the computation of two functions: a normalizing function, which depends both on the coil parameters and the skin depth, and a crack-depth function which depends only on the coil parameters in addition to the crack depth. The practical perfomance of the method was tested using a set of simulated cracks in the form of electro-discharge machined slots in aluminum alloy plates. The crack depths and crack opening deduced from the eddy-current measurements agree with the actual crack dimensions to within 10% or better. Recommendations concerning the optimum conditions for crack sizing are also made.

Hot nuclei, limiting temperatures and excitation energies

International Nuclear Information System (INIS)

Peter, J.

1986-09-01

Hot fusion nuclei are produced in heavy ion collisions at intermediate energies (20-100 MeV/U). Information on the maximum excitation energy per nucleon -and temperatures- indicated by the experimental data is compared to the predictions of static and dynamical calculations. Temperatures around 5-6 MeV are reached and seem to be the limit of formation of thermally equilibrated fusion nuclei

The Raman spectrum and lattice parameters of MgB2 as a function of temperature

International Nuclear Information System (INIS)

Shi Lei; Zhang Huarong; Chen Lin; Feng Yong

2004-01-01

The temperature dependences of the Raman spectrum and lattice parameters of polycrystalline MgB 2 have been investigated by means of Raman spectroscopy and x-ray diffraction. It is found that the lattice parameters show an approximately linear change with the temperature decrease, giving different thermal expansions along the a- and c-axes, which is caused by the comparatively weak metal-boron bonding in MgB 2 . The grain size of MgB 2 determined by means of x-ray diffraction is around 45 nm for both [100] and [001] directions. There is no evidence for any structural transition while the temperature changes from 300 K down to 12 K. An anomalous Raman band at 603 cm -1 is observed, which is consistent with the theoretical prediction for the E 2g in-plane boron stretching mode. The Raman frequency increases and the linewidth decreases as the temperature decreases. A possible origin of the temperature dependences of the Raman frequency and the linewidth is discussed. It is suggested that the grain size effect of MgB 2 on the nanometric scale will have a clear influence on the frequency and the linewidth of the Raman spectrum

Experimental effects of immersion time and water temperature on body condition, burying depth and timing of spawning of the tellinid bivalve Macoma balthica

Science.gov (United States)

de Goeij, Petra; Honkoop, Pieter J.

2003-03-01

The burying depth of many bivalve molluscs on intertidal mudflats varies throughout the year and differs between places. Many factors are known to influence burying depth on a seasonal or spatial scale, with temperature and tidal regime probably being very important. Burying depth, body condition and gonadal development of Macoma balthica were followed throughout winter and spring in an experiment in which water temperature and immersion time were manipulated. Unexpectedly, relative water temperature, in contrast to the prediction, did not generally affect body condition or burying depth. This was probably a consequence of the exceptionally overall low water temperatures during the experimental winter. Differences in temperature did, however, result in different timing of spawning: M. balthica spawned earlier at higher spring temperatures. Longer immersion times led to higher body condition only late in spring, but led to deeper burying throughout almost the whole period. There was no effect of immersion time on the timing of spawning. We conclude that a longer immersion time leads to deeper burying, independent of body condition. We also conclude that burying behaviour of M. balthica is not determined by the moment of spawning.

Temperature dependence of the optical conductivity and penetration depth in superconductor MgB2 film

International Nuclear Information System (INIS)

Moarrefi, M.; Yavari, H.; Elahi, M.

2010-01-01

By using Green's function method the temperature dependence of the optical conductivity and penetration depth of high-quality MgB 2 film are calculated in the framework of the two-band model. We compare our results with experimental data and we argue that the single gap model is insufficient to describe the optical and penetration depth behavior, but the two-band model with different symmetries describes the data rather well. In the two gap model we consider that the both components of optical conductivity are a weighted sum of the contribution from σ and π bonds and hybridization between them is negligible.

Experimental determination of the temperature-dependent penetration depth in V3Si

International Nuclear Information System (INIS)

Christen, D.K.; Kerchner, H.R.; Sekula, S.T.; Chang, Y.K.

1984-03-01

Small angle neutron diffraction from the flux-line lattice (FLL) in a high quality, single crystal of superconducting V 3 Si has been used to deduce the low-field penetration depth lambda (T). An absolute determination is possible because the FLL form factor F/sub hk/ is essentially single-valued in the scattering vector magnitude absolute value of K/sub hk/, as well as nearly London-like at low field. We obtain lambda (0) = 102 +- 1 nm, 20% to 30% larger than previous determinations of the London penetration depth lambda/sub L/ (0). The temperature dependence of lambda (T) is found to deviate from that of the BCS theory. An assessment of the data indicates the most prominent source of the discrepancy is due to strong electron-phonon coupling, and we find 2Δ(0)/k/sub B/T/sub c/ = 3.88 +- 0.07, in reasonable agreement with values found in the literature

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across American Samoa in 2015

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

Absence of zero-temperature transmission rate of a double-chain tight-binding model for DNA with random sequence of nucleotides in thermodynamic limit

International Nuclear Information System (INIS)

Xiong Gang; Wang, X.R.

2005-01-01

The zero-temperature transmission rate spectrum of a double-chain tight-binding model for real DNA is calculated. It is shown that a band of extended-like states exists only for finite chain length with strong inter-chain coupling. While the whole spectrum tends to zero in thermodynamic limit, regardless of the strength of inter-chain coupling. It is also shown that a more faithful model for real DNA with periodic sugar-phosphate chains in backbone structures can be mapped into the above simple double-chain tight-binding model. Combined with above results, the transmission rate of real DNA with long random sequence of nucleotides is expected to be poor

A 0.8-2.4 μm Transmission spectrum of the hot Jupiter CoRoT-1b

Energy Technology Data Exchange (ETDEWEB)

Schlawin, E.; Herter, T. [Astronomy Department, Cornell University, Ithaca, NY 14853 (United States); Zhao, M. [Department of Astronomy, Pennsylvania State University, University Park, PA 16802 (United States); Teske, J. K. [Astronomy Department, The University of Arizona, Tucson, AZ 85721 (United States)

2014-03-01

Hot Jupiters with brightness temperatures ≳2000 K can have TiO and VO molecules as gaseous species in their atmospheres. The TiO and VO molecules can potentially induce temperature inversions in hot Jupiter atmospheres and also have an observable signature of large optical to infrared transit depth ratios. Previous transmission spectra of very hot Jupiters have shown a lack of TiO and VO, but only in planets that also appear to lack temperature inversions. We measure the transmission spectrum of CoRoT-1b, a hot Jupiter that was predicted to have a temperature inversion potentially due to significant TiO and VO in its atmosphere. We employ the multi-object spectroscopy method using the SpeX and MORIS instruments on the Infrared Telescope Facility (IRTF) and the Gaussian process method to model red noise. By using a simultaneous reference star on the slit for calibration and a wide slit to minimize slit losses, we achieve transit depth precision of 0.03%-0.09%, comparable to the atmospheric scale height but detect no statistically significant molecular features. We combine our IRTF data with optical CoRoT transmission measurements to search for differences in the optical and near-infrared absorption that would arise from TiO/VO. Our IRTF spectrum and the CoRoT photometry disfavor a TiO/VO-rich spectrum for CoRoT-1b, suggesting that the atmosphere has another absorber that could create a temperature inversion or that the blackbody-like emission from the planet is due to a spectroscopically flat cloud, dust, or haze layer that smoothes out molecular features in both CoRoT-1b's emission and transmission spectra. This system represents the faintest planet hosting star (K = 12.2) with a measured planetary transmission spectrum.

[Research on the temperature field detection method of hot forging based on long-wavelength infrared spectrum].

Science.gov (United States)

Zhang, Yu-Cun; Wei, Bin; Fu, Xian-Bin

2014-02-01

A temperature field detection method based on long-wavelength infrared spectrum for hot forging is proposed in the present paper. This method combines primary spectrum pyrometry and three-stage FP-cavity LCTF. By optimizing the solutions of three group nonlinear equations in the mathematical model of temperature detection, the errors are reduced, thus measuring results will be more objective and accurate. Then the system of three-stage FP-cavity LCTF was designed on the principle of crystal birefringence. The system realized rapid selection of any wavelength in a certain wavelength range. It makes the response of the temperature measuring system rapid and accurate. As a result, without the emissivity of hot forging, the method can acquire exact information of temperature field and effectively suppress the background light radiation around the hot forging and ambient light that impact the temperature detection accuracy. Finally, the results of MATLAB showed that the infrared spectroscopy through the three-stage FP-cavity LCTF could meet the requirements of design. And experiments verified the feasibility of temperature measuring method. Compared with traditional single-band thermal infrared imager, the accuracy of measuring result was improved.

Abundance of Dreissena polymorpha and Dreissena bugensis in a warmwater plume: effects of depth and temperature

Energy Technology Data Exchange (ETDEWEB)

Mitchell, J.S.; Bailey, R.C.; Knapton, R.W. [Simon Fraser University, Burnaby, BC (Canada). Department of Biological Sciences

1996-08-01

The abundance of mussel populations in areas affected by waste water discharges is examined. Measurements were made of the variation with depth in the abundance of zebra and of quagga mussels both inside and outside the area affected by the warm water plume from the Ontario Hydro Nanticoke coal-fired generating station on Lake Erie. The pattern of the residual variation relative to the warm water plume was then examined. The study allows a partial decoupling of depth and temperature effects. The results are discussed. 27 refs., 2 figs., 2 tabs.

Morse oscillator propagator in the high temperature limit I: Theory

Energy Technology Data Exchange (ETDEWEB)

Toutounji, Mohamad, E-mail: Mtoutounji@uaeu.ac.ae

2017-02-15

In an earlier work of the author the time evolution of Morse oscillator was studied analytically and exactly at low temperatures whereupon optical correlation functions were calculated using Morse oscillator coherent states were employed. Morse oscillator propagator in the high temperature limit is derived and a closed form of its corresponding canonical partition function is obtained. Both diagonal and off-diagonal forms of Morse oscillator propagator are derived in the high temperature limit. Partition functions of diatomic molecules are calculated. - Highlights: • Derives the quantum propagator of Morse oscillator in the high temperature limit. • Uses the resulting diagonal propagator to derive a closed form of Morse oscillator partition function. • Provides a more sophisticated formula of the quantum propagator to test the accuracy of the herein results.

Real-time reactor coolant system pressure/temperature limit system

International Nuclear Information System (INIS)

Newton, D.G.; Schemmel, R.R.; Van Scooter, W.E. Jr.

1991-01-01

This patent describes an system, used in controlling the operating of a nuclear reactor coolant system, which automatically calculates and displays allowable reactor coolant system pressure/temperature limits within the nuclear reactor coolant system based upon real-time inputs. It comprises: means for producing signals representative of real-time operating parameters of the nuclear reactor cooling system; means for developing pressure and temperature limits relating the real-time operating parameters of the nuclear reactor coolant system, for normal and emergency operation thereof; means for processing the signals representative of real-time operating parameters of the nuclear reactor coolant system to perform calculations of a best estimate of signals, check manual inputs against permissible valves and test data acquisition hardware for validity and over/under range; and means for comparing the representative signals with limits for the real-time operating parameters to produce a signal for a real-time display of the pressure and temperature limits and of the real-time operating parameters use an operator in controlling the operation of the nuclear reactor coolant system

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across the Mariana Archipelago in 2014

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across the Hawaiian Archipelago since 2013

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

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

Directory of Open Access Journals (Sweden)

Khanh Dung T Nguyen

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

Planck intermediate results LI. Features in the cosmic microwave background temperature power spectrum and shifts in cosmological parameters

DEFF Research Database (Denmark)

Aghanim, N.; Akrami, Y.; Ashdown, M.

2017-01-01

never before been measured to cosmic-variance level precision. We have investigated these shifts to determine whether they are within the range of expectation and to understand their origin in the data. Taking our parameter set to be the optical depth of the reionized intergalactic medium τ, the baryon...... density ωb, the matter density ωm, the angular size of the sound horizon θ∗, the spectral index of the primordial power spectrum, ns, and Ase- 2τ (where As is the amplitude of the primordial power spectrum), we have examined the change in best-fit values between a WMAP-like large angular-scale data set...

Reconstruct the past thermocline circulation in the Atlantic: calcification depths and Mg/Ca-temperature calibrations for 6 deep-dwelling planktonic foraminifera

Science.gov (United States)

Cleroux, C.; deMenocal, P.; Arbuszewski, J.; Linsley, B.

2012-04-01

The subtropical cells are shallow meridional overturning circulations driven by the atmospheric circulation and the deep thermohaline circulation. They connect the mid-latitude and the tropic, release latten heat to the atmosphere and impact climate on decadal to longer time scale. The upper water column temperature and salinity structures of the ocean reflect this circulation. We present proxies to study these past structures. We performed stable oxygen isotope (δ18O) and trace element ratio measurements on one surface-dwelling (G. ruber)1 and six deep-dwelling planktonic foraminifera species (N. dutertrei, G. inflata, G. tumida, G. truncatulinoides, G. hirsuta and G. crassaformis) on 66 coretops spanning from 35°N to 20°S along the Mid-Atlantic ridge. Comparison between measured δ18O and predicted δ18O (using water column temperature and seawater δ18O), shows that N. dutertrei, G. tumida, G. hirsuta and G. crassaformis keep the same apparent calcification depth along the transect (respectively: 125m, 150m, 700m and 800m). Calcification at two depth levels was also tested. For the six deep-dwelling species, we establish Mg/Ca-temperature calibrations with both atlas temperature at the calcification depth and isotopic temperature. We present Mg/Ca-temperature equations for species previously very poorly calibrated. The δ18O and temperature (Mg/Ca derived) on the six planktonic foraminifera species faithfully reproduce the modern water column structure of the upper 800 m depth, establishing promising proxies for past subsurface reconstruction. 1 Arbuszewski, J. J., P. B. deMenocal, A. Kaplan, and C. E. Farmer (2010), On the fidelity of shell-derived δ18Oseawater estimates, Earth and Planetary Science Letters, 300(3-4), 185-196.

low-Cost, High-Performance Alternatives for Target Temperature Monitoring Using the Near-Infrared Spectrum

Energy Technology Data Exchange (ETDEWEB)

Virgo, Mathew [Argonne National Lab. (ANL), Argonne, IL (United States); Quigley, Kevin J. [Argonne National Lab. (ANL), Argonne, IL (United States); Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Vandegrift, George F. [Argonne National Lab. (ANL), Argonne, IL (United States)

2017-02-01

A process is being developed for commercial production of the medical isotope Mo-99 through a photo-nuclear reaction on a Mo-100 target using a highpower electron accelerator. This process requires temperature monitoring of the window through which a high-current electron beam is transmitted to the target. For this purpose, we evaluated two near infrared technologies: the OMEGA Engineering iR2 pyrometer and the Ocean Optics Maya2000 spectrometer with infrared-enhanced charge-coupled device (CCD) sensor. Measuring in the near infrared spectrum, in contrast to the long-wavelength infrared spectrum, offers a few immediate advantages: (1) ordinary glass or quartz optical elements can be used; (2) alignment can be performed without heating the target; and (3) emissivity corrections to temperature are typically less than 10%. If spatial resolution is not required, the infrared pyrometer is attractive because of its accuracy, low cost, and simplicity. If spatial resolution is required, we make recommendations for near-infrared imaging based on our data augmented by calculations

Exponential Frequency Spectrum in Magnetized Plasmas

International Nuclear Information System (INIS)

Pace, D. C.; Shi, M.; Maggs, J. E.; Morales, G. J.; Carter, T. A.

2008-01-01

Measurements of a magnetized plasma with a controlled electron temperature gradient show the development of a broadband spectrum of density and temperature fluctuations having an exponential frequency dependence at frequencies below the ion cyclotron frequency. The origin of the exponential frequency behavior is traced to temporal pulses of Lorentzian shape. Similar exponential frequency spectra are also found in limiter-edge plasma turbulence associated with blob transport. This finding suggests a universal feature of magnetized plasma turbulence leading to nondiffusive, cross-field transport, namely, the presence of Lorentzian shaped pulses

Limit temperature for entanglement in generalized statistics

International Nuclear Information System (INIS)

Rossignoli, R.; Canosa, N.

2004-01-01

We discuss the main properties of general thermal states derived from non-additive entropic forms and their use for studying quantum entanglement. It is shown that all these states become more mixed as the temperature increases, approaching the full random state for T→∞. The formalism is then applied to examine the limit temperature for entanglement in a two-qubit XXZ Heisenberg chain, which exhibits the peculiar feature of being independent of the applied magnetic field in the conventional von Neumann based statistics. In contrast, this temperature is shown to be field dependent in a generalized statistics, even for small deviations from the standard form. Results for the Tsallis-based statistics are examined in detail

Redetermination of the X-ray spectrum of SN 1006 and excess diffuse emission from the Lupus region

Energy Technology Data Exchange (ETDEWEB)

Koyama, Katsuji; Tsunemi, Hiroshi; Becker, R H; Hughes, J P

1987-01-01

X-ray from SN 1006 and from the adjacent Lupus region were separately observed with the Tenma gas scintillation proportional counters. The spectrum of the local excess emission from the Lupus region can be consistently fitted with either a thin thermal bremsstrahlung spectrum with a temperature of 7.5 +- 2.6 keV or a power-law spectrum with a photon index of 2.1 +- 0.1. The x-ray emission from SN 1006, after subtraction of this local excess, has a spectrum which can be described as a power-law spectrum with a photon index of 3.3 +- 0.1 or a thin thermal bremsstrahlung spectrum with a temperature of 1.9 +- 0.1 keV which is much softer than the previously reported spectrum. No significant iron line emission was observed in the SN 1006 spectrum. The 90 % upper limit for the equivalent width of the iron line was reduced to 400 eV. The observed spectrum can also be interpreted in terms of a nonequilibrium ionization model of about 2-keV electron temperature.

Temperature and isotope effects on the shape of the optical absorption spectrum of solvated electrons in water

International Nuclear Information System (INIS)

Jou, F.Y.; Freeman, G.R.

1979-01-01

The optical absorption spectra of solvated electrons in H 2 O and D 2 O have been measured at 274, 298, 340, and 380 K. All the spectra were fitted very well with the Gaussian and Lorentzian shape functions at the low- and high-energy sides of the absorption maximum, respectively, excluding the high-energy tail. The spectrum does not shift uniformly with temperature. The temperature coefficient of absorption decreases rapidly with increasing energy on the low-energy side of the absorption maximum, while it changes only slightly on the high-energy side. When the temperature increases the Lorentzian width remains constant, the Gaussian width varies proportionally to T/sup 1/2/, and the spectrum becomes more symmetrical. On going from H 2 O to D 2 O we found that the spectrum at a given A/A/sub max/ shows a shift of +0.05 eV in the low-energy wing. The shift decreases with increasing energy, reaching 0.03 eV at the absorption maximum. On the high-energy side of the band the shift becomes negative at hν > 2.2 eV. The shift on the low-energy side seems to be related to the difference of the zero-point energies of the inter- and intramolecular vibrations. The wavelength dependence of the temperature and isotope effects is consistent with the model that different types of excitation occur on the low- and high-energy sides of the absorption band. The temperature and isotopic dependence of the low-energy side are consistent with its width being due to phonon interactions

A new method for detection of the electron temperature in laser-plasma short wave cut off of stimulated Raman scattering spectrum

International Nuclear Information System (INIS)

Zhang Jiatai

1994-01-01

From the theory of stimulated Raman scattering (SRS) three wave interaction, a new method of detecting the electron temperature in laser-plasma is obtained. SRS spectrum obtained from Shenguang No. 12 Nd-laser experiments are analysed. Using the wave length of short wave cut off of SRS, the electron temperature in corona plasma region is calculated consistently. These results agree reasonable with X-ray spectrum experiments

Temperature effects in an optical limiter using carbon nanotube suspensions

International Nuclear Information System (INIS)

Yu, Hyojung; Kim, Sokwon

2005-01-01

An optical limiter is an optical component that reduces the laser beam intensity for the protection of eyes and light sensors, and a carbon nanotube is known to be a highly efficient optical limiting material. However, the effects of heat generated by continuous use have not been studied yet. Therefore, in this work, the variation of optical limiting effect of multi-walled carbon-nanotube suspensions in several kinds of solvents such as distilled water, chloroform, ethanol and ethylene glycol, were measured in the temperature range from room temperature to the boiling point of each solvent. A pulsed Nd : YAG laser with a wavelength of 1064 nm and a pulse duration of 6 ns was used as the light source. The experimental result shows that the limiting efficiencies of all the suspensions were reduced as the temperature was increased and that a suspension with a solvent of lower boiling point, viscosity, and surface tension showed a higher efficiency.

Time-temperature-burial significance of Devonian anthracite implies former great (approx.6.5 km) depth of burial of Catskill Mountains, New York

International Nuclear Information System (INIS)

Friedman, G.M.; Sanders, J.E.

1982-01-01

Specimens of coalified plant debris in Tully-correlative strata of the Gilboa Formation (uppermost Middle Devonian) within the eastern Catskill Mountains of New York State have been converted to anthracite having a vitrinite reflectance of 2.5%. This implies a level of organic metamorphism (LOM) of 16. The specimens are about 350 m.y. old; if 200 m.y. is taken as the duration of the time of exposure to the maximum geothermal temperature, then the LOM of 16 and other thermal indicators imply a maximum temperature of 190 0 C. Using a geothermal gradient of 26 0 C.km -1 (17 0 F.1,000 ft -1 ), a former depth of burial of 6.5 km is implied. Such former deep burial is not usually inferred for the Catskills, but it is consistent with the idea that the thick (about 6.4 km or 21,000 ft) Carboniferous strata of northeastern Pennsylvania formerly extended northeast far enough to bury the Catskills. The lack of metamorphism of the Paleozoic strata lying about 4.5 km beneath the Tully-correlative rocks and exposed in the adjacent Hudson Valley places low limits on the former geothermal gradient; this supports the concept of great depth of former burial of the Catskills. For example, 6.5 km of former burial and a geothermal gradient of 26 0 C.km -1 imply a temperature of 307 0 C for the base of the Paleozoic. By contrast, only 1 km of former burial requires a geothermal gradient of 170 0 C.km -1 , which would have subjected the base of the Paleozoic to a temperature of 955 0 GAMMA, which is far higher than the 600 to 650 0 C recently inferred for the Acadian-age metamorphism of the Taconic allochthon in southwestern Massachusetts and adjoining areas

SY-101 Rapid Transfer Project Low Temperature Operations Review and Recommendations to Support Lower Temperature Limits

International Nuclear Information System (INIS)

HICKMAN, G.L.

2000-01-01

The lower temperature limit for the 241 SY-101 RAPID transfer project is currently set at 20 F Based on the analysis and recommendations in this document this limit can be lowered to 0 F. Analysis of all structures systems and components (SSCs) indicate that a reduction in operating temperature may be achieved with minor modifications to field-installed equipment. Following implementation of these changes it is recommended that the system requirements be amended to specify a temperature range for transfer or back dilute evolutions of 0 F to 100 F

Study of temperature increase and optic depth penetration in photo irradiated human tissues

International Nuclear Information System (INIS)

Stolik, Suren; Delgado, Jose A.; Perez, Arllene M.; Anasagasti, Lorenzo

2009-01-01

Optical radiation is widely applied in the treatment and diagnosis of different pathologies. If the power density of the incident light is sufficiently high to induce a significant temperature rise in the irradiated tissue, then it is also needed the knowledge of the thermal properties of the tissue for a complete understanding of the therapeutic effects. The thermal penetration depth of several human tissues has been measured applying the diffusion approximation of the radiative transfer equation for the distribution of optical radiation. The method, the experimental setup and the results are presented and discussed. (Author)

Optical power limiting and transmitting properties of cadmium iodide single crystals: Temperature dependence

Energy Technology Data Exchange (ETDEWEB)

Miah, M. Idrish, E-mail: m.miah@griffith.edu.a [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)] [Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)] [Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)

2009-09-14

Optical limiting properties of the single crystals of cadmium iodide are investigated using ns laser pulses. It is found that the transmissions in the crystals increase with increasing temperature. However, they limit the transmissions at high input powers. The limiting power is found to be higher at higher temperature. From the measured transmission data, the photon absorption coefficients are estimated. The temperature dependence of the coefficients shows a decrease in magnitude with increasing temperature. This might be due to the temperature-dependent bandgap shift of the material. The results demonstrate that the cadmium iodide single crystals are promising materials for applications in optical power limiting devices.

Optical power limiting and transmitting properties of cadmium iodide single crystals: Temperature dependence

International Nuclear Information System (INIS)

Miah, M. Idrish

2009-01-01

Optical limiting properties of the single crystals of cadmium iodide are investigated using ns laser pulses. It is found that the transmissions in the crystals increase with increasing temperature. However, they limit the transmissions at high input powers. The limiting power is found to be higher at higher temperature. From the measured transmission data, the photon absorption coefficients are estimated. The temperature dependence of the coefficients shows a decrease in magnitude with increasing temperature. This might be due to the temperature-dependent bandgap shift of the material. The results demonstrate that the cadmium iodide single crystals are promising materials for applications in optical power limiting devices.

High temperature corrosion under conditions simulating biomass firing: depth-resolved phase identification

DEFF Research Database (Denmark)

Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

2014-01-01

) were coated with KCl and is o-thermally exposed at 560 o C for 168 h under a flue gas corresponding to straw firing. Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), and X-ray Diffraction (XRD) characterization techniques were employed for comprehensive characterization......Both cross-sectional and plan view, ‘top-down’ characterization methods were employed , for a depth-resolved characterization of corrosion products resulting from high temperature corrosion under laboratory conditions simulating biomass firing. Samples of an austenitic stainless steel (TP 347H FG...... of the corrosion product. Results from this comprehensive characterization revealed more details on the morphology and composition of the corrosion product....

Germination responses of Cañahua (Chenopodium pallidicaule Aellen) to temperature and sowing depth

DEFF Research Database (Denmark)

Rodriguez Calle, Juan Pablo; Jacobsen, Sven-Erik; Sørensen, Marten

2016-01-01

Cañahua (Chenopodium pallidicaule) is grown in the Altiplano of Bolivia and Peru, between 3810 and 4200 m a.s.l. Rural indigenous households have cultivated the cañahua as a subsistence crop for millennia. The seeds have a high content and quality of protein. We studied the relation between...... the following: (i) temperature and seed germination and (ii) the effect of temperature and sowing depth on seedling emergence of five cultivars and one landrace. Three experiments were conducted as follows: (i) seeds of a cultivar were germinated in Petri dishes at six temperatures (3, 5, 10, 14, 20 and 24 °C...... significantly effect on the germination percentages of the plants (P Seeds germinated at the lowest temperature (3 °C). The estimated base temperature was close to 0 °C. A polynomial function described well the relation between time to 50% germination (t50) and temperature in the interval from 3 to 24...

A redetermination of the X-ray spectrum of SN 1006 and excess diffuse emission from the Lupus region

International Nuclear Information System (INIS)

Koyama, Katsuji; Tsunemi, Hiroshi; Becker, R.H.; Hughes, J.P.

1987-01-01

X-ray from SN 1006 and from the adjacent Lupus region were separately observed with the Tenma gas scintillation proportional counters. The spectrum of the local excess emission from the Lupus region can be consistently fitted with either a thin thermal bremsstrahlung spectrum with a temperature of 7.5 ± 2.6 keV or a power-law spectrum with a photon index of 2.1 ± 0.1. The x-ray emission from SN 1006, after subtraction of this local excess, has a spectrum which can be described as a power-law spectrum with a photon index of 3.3 ± 0.1 or a thin thermal bremsstrahlung spectrum with a temperature of 1.9 ± 0.1 keV which is much softer than the previously reported spectrum. No significant iron line emission was observed in the SN 1006 spectrum. The 90 % upper limit for the equivalent width of the iron line was reduced to 400 eV. The observed spectrum can also be interpreted in terms of a nonequilibrium ionization model of about 2-keV electron temperature. (author)

Low plasma edge temperatures for the self-pumped limiter

International Nuclear Information System (INIS)

Terry, W.K.; Brooks, J.N.

1985-03-01

Transport code calculations have been performed to study the operation of an INTOR-like tokamak plasma from which helium is removed by a self-pumped limiter, which traps helium, but not hydrogen, in its surface layers. To prevent saturation by helium, the surface is renewed by continuous injection of the surface material (vanadium in this study) into the scrape-off layer. The presence of the injected vanadium leads to plasma temperatures well below 50 eV in the scrape-off layer, with supplementary rf heating. Operation in this edge temperature regime is essential for the use of medium- and high-Z limiter coatings

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

Science.gov (United States)

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

2017-10-01

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

Joint opportunistic beam and spectrum selection schemes for spectrum sharing systems with limited feedback

KAUST Repository

Sayed, Mostafa M.

2014-11-01

Spectrum sharing systems have been introduced to alleviate the problem of spectrum scarcity by allowing an unlicensed secondary user (SU) to share the spectrum with a licensed primary user (PU) under acceptable interference levels to the primary receiver (PU-Rx). In this paper, we consider a secondary link composed of a secondary transmitter (SU-Tx) equipped with multiple antennas and a single-antenna secondary receiver (SU-Rx). The secondary link is allowed to share the spectrum with a primary network composed of multiple PUs communicating over distinct frequency spectra with a primary base station. We develop a transmission scheme where the SU-Tx initially broadcasts a set of random beams over all the available primary spectra for which the PU-Rx sends back the index of the spectrum with the minimum interference level, as well as information that describes the interference value, for each beam. Based on the feedback information on the PU-Rx, the SU-Tx adapts the transmitted beams and then resends the new beams over the best primary spectrum for each beam to the SU-Rx. The SU-Rx selects the beam that maximizes the received signal-to-interference-plus-noise ratio (SINR) to be used in transmission over the next frame. We consider three cases for the level of feedback information describing the interference level. In the first case, the interference level is described by both its magnitude and phase; in the second case, only the magnitude is considered; and in the third case, we focus on a q-bit description of its magnitude. In the latter case, we propose a technique to find the optimal quantizer thresholds in a mean-square-error sense. We also develop a statistical analysis for the SINR statistics and the capacity and bit error rate of the secondary link and present numerical results that study the impact of the different system parameters.

The emergent 1.1-1.7 μm spectrum of the exoplanet COROT-2B as measured using the Hubble space telescope

International Nuclear Information System (INIS)

Wilkins, Ashlee N.; Deming, Drake; Madhusudhan, Nikku; Burrows, Adam; Knutson, Heather; McCullough, Peter; Ranjan, Sukrit

2014-01-01

We have used Hubble/WFC3 and the G141 grism to measure the secondary eclipse of the transiting, very hot Jupiter CoRoT-2b in the 1.1-1.7 μm spectral region. We find an eclipse depth averaged over this band equal to 395 −45 +69 parts per million, equivalent to a blackbody temperature of 1788 ± 18 K. We study and characterize several WFC3 instrumental effects, especially the 'hook' phenomenon described by Deming et al. We use data from several transiting exoplanet systems to find a quantitative relation between the amplitude of the hook and the exposure level of a given pixel. Although the uncertainties in this relation are too large to allow us to develop an empirical correction for our data, our study provides a useful guide for optimizing exposure levels in future WFC3 observations. We derive the planet's spectrum using a differential method. The planet-to-star contrast increases to longer wavelength within the WFC3 bandpass, but without water absorption or emission to a 3σ limit of 85 ppm. The slope of the WFC3 spectrum is significantly less than the slope of the best-fit blackbody. We compare all existing eclipse data for this planet to a blackbody spectrum, and to spectra from both solar abundance and carbon-rich (C/O = 1) models. A blackbody spectrum is an acceptable fit to the full data set. Extra continuous opacity due to clouds or haze, and flattened temperature profiles, are strong candidates to produce quasi-blackbody spectra, and to account for the amplitude of the optical eclipses. Our results show ambiguous evidence for a temperature inversion in this planet.

The emergent 1.1-1.7 μm spectrum of the exoplanet COROT-2B as measured using the Hubble space telescope

Energy Technology Data Exchange (ETDEWEB)

Wilkins, Ashlee N.; Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Madhusudhan, Nikku [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06511 (United States); Burrows, Adam [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544-1001 (United States); Knutson, Heather [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); McCullough, Peter [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Ranjan, Sukrit, E-mail: awilkins@astro.umd.edu [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

2014-03-10

We have used Hubble/WFC3 and the G141 grism to measure the secondary eclipse of the transiting, very hot Jupiter CoRoT-2b in the 1.1-1.7 μm spectral region. We find an eclipse depth averaged over this band equal to 395{sub −45}{sup +69} parts per million, equivalent to a blackbody temperature of 1788 ± 18 K. We study and characterize several WFC3 instrumental effects, especially the 'hook' phenomenon described by Deming et al. We use data from several transiting exoplanet systems to find a quantitative relation between the amplitude of the hook and the exposure level of a given pixel. Although the uncertainties in this relation are too large to allow us to develop an empirical correction for our data, our study provides a useful guide for optimizing exposure levels in future WFC3 observations. We derive the planet's spectrum using a differential method. The planet-to-star contrast increases to longer wavelength within the WFC3 bandpass, but without water absorption or emission to a 3σ limit of 85 ppm. The slope of the WFC3 spectrum is significantly less than the slope of the best-fit blackbody. We compare all existing eclipse data for this planet to a blackbody spectrum, and to spectra from both solar abundance and carbon-rich (C/O = 1) models. A blackbody spectrum is an acceptable fit to the full data set. Extra continuous opacity due to clouds or haze, and flattened temperature profiles, are strong candidates to produce quasi-blackbody spectra, and to account for the amplitude of the optical eclipses. Our results show ambiguous evidence for a temperature inversion in this planet.

Effects of aromaticity in cations and their functional groups on the temperature dependence of low-frequency spectrum

Science.gov (United States)

Kakinuma, Shohei; Ramati, Sharon; Wishart, James F.; Shirota, Hideaki

2018-05-01

In this study, we investigate the temperature dependence of low-frequency spectra in the frequency range of 0.3-200 cm-1 for ionic liquids (ILs) whose cations possess two systematically different cyclic groups, using femtosecond Raman-induced Kerr effect spectroscopy. The target ILs are bis(trifluoromethylsulfonyl)amide [NTf2]- salts of 1-cyclohexylmethyl-1-methylpyrrolidinium [CHxmMPyrr]+, 1-cyclohexylmethyl-3-methylimidazolium [CHxmMIm]+, N-cyclohexylmethylpyridinium [CHxmPy]+, 1-benzyl-1-methylpyrrolidinium [BzMPyrr]+, 1-benzyl-3-methylimidazolium [BzMIm]+, and N-benzylpyridinium [BzPy]+ cations. The aim of this study is to better understand the effects of aromaticity in the cations' constituent groups on the temperature-dependent low-frequency spectral features of the ILs. The low-frequency spectra of these ILs are temperature dependent, but the temperature-dependent spectrum of [CHxmMPyrr][NTf2] is different from that of other ILs. While [CHxmMPyrr][NTf2] shows spectral changes with temperature in the low-frequency region below 50 cm-1, the other ILs also show spectral changes in the high-frequency region above 80 cm-1 (above 50 cm-1 in the case of [BzMPyrr][NTf2]). We conclude that the spectral change in the low-frequency region is due to both the cation and anion, while the change in the high-frequency region is attributed to the red shift of the aromatic ring librations. On the basis of the plots of the first moment of the spectra vs. temperature, we found that the first moment of the low-frequency spectrum of the IL whose cation does not have an aromatic ring is less temperature dependent than that of the other ILs. However, the intrinsic first moment, the first moment at 0 K, of the low-frequency spectrum is governed by the absence or presence of a charged aromatic group, while a neutral aromatic group does not have much influence on determining the intrinsic first moment.

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across the Pacific Remote Island Areas since 2014

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

Braked rotation of CH3 group in L-alanine monocrystals: temperature transformation of EPR spectrum

International Nuclear Information System (INIS)

Lemanov, V.V.; Sochava, L.S.

2003-01-01

EPR spectra temperature transformation of the irradiated alanine crystals is used for studying rotation of CH 3 methyl group in L-alamine monocrystals. 60 Co (2 x 10 4 Gy dose) was applied as a γ-radiation source. The simple method of experimental data processing which is reduced to obtaining the resonance lines width dependence on the temperature is used for the quantitative analysis of the spectrum temperature transformation. Temperature dependence of the CH 3 group rotation frequency is identified on the basis of these data. Activation energy U = 0.18 eV and pre-exponential multiplier ω 0 = 10 13 s -1 are determined from the EPR spectra temperature transformation which are in good agreement with values obtained earlier from the measurements of the proton spin-lattice relaxation in alanine polycrystal samples [ru

Tree density and permafrost thaw depth influence water limitations on stomatal conductance in Siberian Arctic boreal forests

Science.gov (United States)

Kropp, H.; Loranty, M. M.; Natali, S.; Kholodov, A. L.; Alexander, H. D.; Zimov, N.

2017-12-01

Boreal forests may experience increased water stress under global climate change as rising air temperatures increase evaporative demand and decrease soil moisture. Increases in plant water stress can decrease stomatal conductance, and ultimately, decrease primary productivity. A large portion of boreal forests are located in Siberia, and are dominated by deciduous needleleaf trees, Larix spp. We investigated the variability and drivers of canopy stomatal conductance in upland Larix stands with different stand density that arose from differing fire severity. Our measurements focus on an open canopy stand with low tree density and deep permafrost thaw depth, and a closed canopy stand with high tree density and shallow permafrost thaw depth. We measured canopy stomatal conductance, soil moisture, and micrometeorological variables. Our results demonstrate that canopy stomatal conductance was significantly lower in the closed canopy stand with a significantly higher sensitivity to increases in atmospheric evaporative demand. Canopy stomatal conductance in both stands was tightly coupled to precipitation that occurred over the previous week; however, the closed canopy stand showed a significantly greater sensitivity to increases in precipitation compared to the open canopy stand. Differences in access to deep versus shallow soil moisture and the physical characteristics of the soil profile likely contribute to differences in sensitivity to precipitation between the two stands. Our results indicate that Larix primary productivity may be highly sensitive to changes in evaporative demand and soil moisture that can result of global climate change. However, the effect of increasing air temperatures and changes in precipitation will differ significantly depending on stand density, thaw depth, and the hydraulic characteristics of the soil profile.

New measurements of the spectrum of the cosmic microwave background

International Nuclear Information System (INIS)

Peterson, J.B.; Richards, P.L.; Bonomo, J.L.; Timusk, T.

1986-01-01

Accurate measurements of the spectrum of the cosmic microwave background (CMB) can provide useful tests of cosmological theories. The data set existing in 1982 has been summarized on a number of occasions. To first approximation the CMB is characterized by a single temperature and thus has a blackbody spectrum over the frequency range from 0.02 to 24 cm/sup -1/. The error limits given for these experiments are dominated by systematic errors and are often very subjective. Consequently, it is not clear how to analyze the data set in a valid way. The general impression, however, is of a scatter in the high frequency data that is somewhat larger than would be expected from the given error limits

Evidence for a continuous spectrum of equatorial waves in the Indian Ocean

Science.gov (United States)

Eriksen, Charles C.

1980-06-01

Seven-month records of current and temperature measurements from a moored array centered at 53°E on the equator in the Indian Ocean are consistent with a continuous spectrum of equatorially trapped internal inertial-gravity, mixed Rossby-gravity, and Kelvin waves. A model spectrum of free linear waves analogous to those for mid-latitude internal gravity waves is used to compute spectra of observed quantities at depths greater than about 2000 m. Model parameters are adjusted to fit general patterns in the observed spectra over periods from roughly 2 days to 1 month. Measurements at shallower depths presumably include forced motions which we have not attempted to model. This `straw-person' spectrum is consistent with the limited data available. The model spectru Ē (n, m, ω) = K · B(m) · C(n, ω), where Ē is an average local energy density in the equatorial wave guide which has amplitude K, wave number shape B(m) ∝ (1 + m/m*)-3, where m is vertical mode number and the bandwidth parameter m* is between 4 and 8, and frequency shape C(n, ω) ∝ [(2n + 1 + s2)½ · σ3]-1 where n is meridional mode number, and s and σ are dimensionless zonal wave number and frequency related by the usual dispersion relation. The scales are (β/cm)½ and (β · cm)½ for horizontal wave number and frequency, where cm is the Kelvin wave speed of the vertical mode m. At each frequency and vertical wave number, energy is partitioned equally among the available inertial gravity modes so that the field tends toward horizontal isotropy at high frequency. The transition between Kelvin and mixed Rossby-gravity motion at low frequency and inertial-gravity motion at high frequency occurs at a period of roughly 1 week. At periods in the range 1-3 weeks, the model spectrum which fits the observations suggests that mixed Rossby-gravity motion dominates; at shorter periods gravity motion dominates. The model results are consistent with the low vertical coherence lengths observed (roughly 80 m

On the Soft Limit of the Large Scale Structure Power Spectrum: UV Dependence

CERN Document Server

Garny, Mathias; Porto, Rafael A; Sagunski, Laura

2015-01-01

We derive a non-perturbative equation for the large scale structure power spectrum of long-wavelength modes. Thereby, we use an operator product expansion together with relations between the three-point function and power spectrum in the soft limit. The resulting equation encodes the coupling to ultraviolet (UV) modes in two time-dependent coefficients, which may be obtained from response functions to (anisotropic) parameters, such as spatial curvature, in a modified cosmology. We argue that both depend weakly on fluctuations deep in the UV. As a byproduct, this implies that the renormalized leading order coefficient(s) in the effective field theory (EFT) of large scale structures receive most of their contribution from modes close to the non-linear scale. Consequently, the UV dependence found in explicit computations within standard perturbation theory stems mostly from counter-term(s). We confront a simplified version of our non-perturbative equation against existent numerical simulations, and find good agr...

Breaking the Crowther limit: Combining depth-sectioning and tilt tomography for high-resolution, wide-field 3D reconstructions

International Nuclear Information System (INIS)

Hovden, Robert; Ercius, Peter; Jiang, Yi; Wang, Deli; Yu, Yingchao; Abruña, Héctor D.; Elser, Veit; Muller, David A.

2014-01-01

To date, high-resolution ( 6 nm) to appear blurred or missing. Here we demonstrate a three-dimensional imaging method that overcomes both these limits by combining through-focal depth sectioning and traditional tilt-series tomography to reconstruct extended objects, with high-resolution, in all three dimensions. The large convergence angle in aberration corrected instruments now becomes a benefit and not a hindrance to higher quality reconstructions. A through-focal reconstruction over a 390 nm 3D carbon support containing over 100 dealloyed and nanoporous PtCu catalyst particles revealed with sub-nanometer detail the extensive and connected interior pore structure that is created by the dealloying instability. - Highlights: • Develop tomography technique for high-resolution and large field of view. • We combine depth sectioning with traditional tilt tomography. • Through-focal tomography reduces tilts and improves resolution. • Through-focal tomography overcomes the fundamental Crowther limit. • Aberration-corrected becomes a benefit and not a hindrance for tomography

The infrared spectrum of Jupiter

Science.gov (United States)

Ridgway, S. T.; Larson, H. P.; Fink, U.

1976-01-01

The principal characteristics of Jupiter's infrared spectrum are reviewed with emphasis on their significance for our understanding of the composition and temperature structure of the Jovian upper atmosphere. The spectral region from 1 to 40 microns divides naturally into three regimes: the reflecting region, thermal emission from below the cloud deck (5-micron hot spots), and thermal emission from above the clouds. Opaque parts of the Jovian atmosphere further subdivide these regions into windows, and each is discussed in the context of its past or potential contributions to our knowledge of the planet. Recent results are incorporated into a table of atmospheric composition and abundance which includes positively identified constituents as well as several which require verification. The limited available information about spatial variations of the infrared spectrum is presented

Comparison of Decisions Quality of Heuristic Methods with Limited Depth-First Search Techniques in the Graph Shortest Path Problem

Directory of Open Access Journals (Sweden)

Vatutin Eduard

2017-12-01

Full Text Available The article deals with the problem of analysis of effectiveness of the heuristic methods with limited depth-first search techniques of decision obtaining in the test problem of getting the shortest path in graph. The article briefly describes the group of methods based on the limit of branches number of the combinatorial search tree and limit of analyzed subtree depth used to solve the problem. The methodology of comparing experimental data for the estimation of the quality of solutions based on the performing of computational experiments with samples of graphs with pseudo-random structure and selected vertices and arcs number using the BOINC platform is considered. It also shows description of obtained experimental results which allow to identify the areas of the preferable usage of selected subset of heuristic methods depending on the size of the problem and power of constraints. It is shown that the considered pair of methods is ineffective in the selected problem and significantly inferior to the quality of solutions that are provided by ant colony optimization method and its modification with combinatorial returns.

Comparison of Decisions Quality of Heuristic Methods with Limited Depth-First Search Techniques in the Graph Shortest Path Problem

Science.gov (United States)

Vatutin, Eduard

2017-12-01

The article deals with the problem of analysis of effectiveness of the heuristic methods with limited depth-first search techniques of decision obtaining in the test problem of getting the shortest path in graph. The article briefly describes the group of methods based on the limit of branches number of the combinatorial search tree and limit of analyzed subtree depth used to solve the problem. The methodology of comparing experimental data for the estimation of the quality of solutions based on the performing of computational experiments with samples of graphs with pseudo-random structure and selected vertices and arcs number using the BOINC platform is considered. It also shows description of obtained experimental results which allow to identify the areas of the preferable usage of selected subset of heuristic methods depending on the size of the problem and power of constraints. It is shown that the considered pair of methods is ineffective in the selected problem and significantly inferior to the quality of solutions that are provided by ant colony optimization method and its modification with combinatorial returns.

New measurements of the spectrum of the cosmic microwave background

International Nuclear Information System (INIS)

Peterson, J.B.; Richards, P.L.; Bonomo, J.L.; Timusk, T.

1984-06-01

Accurate measurements of the spectrum of the cosmic microwave background (CMB) can provide useful tests of cosmological theories. The data set existing in 1982 has been summarized on a number of occasions and is shown. To first approximation the CMB is characterized by a single temperature and thus has a blackbody spectrum over the frequency range from 0.02 to 24 cm -1 . The error limits given for these experiments are dominated by systematic errors and are often very subjective. Consequently, it is not clear how to analyze the data set in a valid way. The general impression, however, is of a scatter in the high frequency data that is somewhat larger than would be expected from the given error limits. We have designed a new apparatus to measure the spectrum of the CMB in the frequency range from 3 to 10 cm -1 . 13 references, 5 figures

Space charge limited conduction in CdSe thin films

Indian Academy of Sciences (India)

Unknown

of trap limited space charge limited conduction (SCLC) at higher voltage. The transition voltage (Vt ) from ohmic to SCLC is found to be quite independent of ambient temperature as well as intensity of illumination. SCLC is explained on the basis of the exponential trap distribution in CdSe films. Trap depths estimated from.

High temperature performance limit of containment system of transport cask

International Nuclear Information System (INIS)

Kato, Osamu; Saegusa, Toshiari

1998-01-01

The containment performance of a containment system using elastomer gaskets for transport casks under a high temperature and high pressure was clarified. Major results are as follows; (1) The deformation characteristics of the gaskets were represented by the compressive permanent strain rate (Dp). The temperature and time dependence was shown by Larson-Miller Parameter (LMP). (2) Generally, the high temperature performance limit is obtained by a value of LMP when the Dp value reaches 80%. However, the gaskets (FKM, VMQ, EPDM) used for real transport casks were not damaged and the containment performance was not deteriorated as a conservative condition. (3) Assuming that the service period of the gaskets for transport casks is 3 months or 1 year, the high temperature performance limit of the gasket made of fluorine rubber (FKM) is 202degC or 182degC, respectively, which includes safety margin. (author)

Breaking the Crowther limit: Combining depth-sectioning and tilt tomography for high-resolution, wide-field 3D reconstructions

Energy Technology Data Exchange (ETDEWEB)

Hovden, Robert, E-mail: rmh244@cornell.edu [School of Applied and Engineering Physics and Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853 (United States); Ercius, Peter [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Jiang, Yi [Department of Physics, Cornell University, Ithaca, NY 14853 (United States); Wang, Deli; Yu, Yingchao; Abruña, Héctor D. [Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853 (United States); Elser, Veit [Department of Physics, Cornell University, Ithaca, NY 14853 (United States); Muller, David A. [School of Applied and Engineering Physics and Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, NY 14853 (United States)

2014-05-01

To date, high-resolution (<1 nm) imaging of extended objects in three-dimensions (3D) has not been possible. A restriction known as the Crowther criterion forces a tradeoff between object size and resolution for 3D reconstructions by tomography. Further, the sub-Angstrom resolution of aberration-corrected electron microscopes is accompanied by a greatly diminished depth of field, causing regions of larger specimens (>6 nm) to appear blurred or missing. Here we demonstrate a three-dimensional imaging method that overcomes both these limits by combining through-focal depth sectioning and traditional tilt-series tomography to reconstruct extended objects, with high-resolution, in all three dimensions. The large convergence angle in aberration corrected instruments now becomes a benefit and not a hindrance to higher quality reconstructions. A through-focal reconstruction over a 390 nm 3D carbon support containing over 100 dealloyed and nanoporous PtCu catalyst particles revealed with sub-nanometer detail the extensive and connected interior pore structure that is created by the dealloying instability. - Highlights: • Develop tomography technique for high-resolution and large field of view. • We combine depth sectioning with traditional tilt tomography. • Through-focal tomography reduces tilts and improves resolution. • Through-focal tomography overcomes the fundamental Crowther limit. • Aberration-corrected becomes a benefit and not a hindrance for tomography.

Response of seasonal soil freeze depth to climate change across China

Science.gov (United States)

Peng, Xiaoqing; Zhang, Tingjun; Frauenfeld, Oliver W.; Wang, Kang; Cao, Bin; Zhong, Xinyue; Su, Hang; Mu, Cuicui

2017-05-01

The response of seasonal soil freeze depth to climate change has repercussions for the surface energy and water balance, ecosystems, the carbon cycle, and soil nutrient exchange. Despite its importance, the response of soil freeze depth to climate change is largely unknown. This study employs the Stefan solution and observations from 845 meteorological stations to investigate the response of variations in soil freeze depth to climate change across China. Observations include daily air temperatures, daily soil temperatures at various depths, mean monthly gridded air temperatures, and the normalized difference vegetation index. Results show that soil freeze depth decreased significantly at a rate of -0.18 ± 0.03 cm yr-1, resulting in a net decrease of 8.05 ± 1.5 cm over 1967-2012 across China. On the regional scale, soil freeze depth decreases varied between 0.0 and 0.4 cm yr-1 in most parts of China during 1950-2009. By investigating potential climatic and environmental driving factors of soil freeze depth variability, we find that mean annual air temperature and ground surface temperature, air thawing index, ground surface thawing index, and vegetation growth are all negatively associated with soil freeze depth. Changes in snow depth are not correlated with soil freeze depth. Air and ground surface freezing indices are positively correlated with soil freeze depth. Comparing these potential driving factors of soil freeze depth, we find that freezing index and vegetation growth are more strongly correlated with soil freeze depth, while snow depth is not significant. We conclude that air temperature increases are responsible for the decrease in seasonal freeze depth. These results are important for understanding the soil freeze-thaw dynamics and the impacts of soil freeze depth on ecosystem and hydrological process.

A video-rate range sensor based on depth from defocus

OpenAIRE

Ghita, Ovidiu; Whelan, Paul F.

2001-01-01

Recovering the depth information derived from dynamic scenes implies real-time range estimation. This paper addresses the implementation of a bifocal range sensor which estimates the depth by measuring the relative blurring between two images captured with different focal settings. To recover the depth accurately even in cases when the scene is textureless, one possible solution is to project a structured light on the scene. As a consequence, in the scene's spectrum a spatial frequency derive...

Regulating the Emission Spectrum of CsPbBr₃ from Green to Blue via Controlling the Temperature and Velocity of Microchannel Reactor.

Science.gov (United States)

Tang, Yong; Lu, Hanguang; Rao, Longshi; Li, Zongtao; Ding, Xinrui; Yan, Caiman; Yu, Binhai

2018-03-02

The ability to precisely obtain tunable spectrum of lead halide perovskite quantum dots (QDs) is very important for applications, such as in lighting and display. Herein, we report a microchannel reactor method for synthesis of CsPbBr₃ QDs with tunable spectrum. By adjusting the temperature and velocity of the microchannel reactor, the emission peaks of CsPbBr₃ QDs ranging from 520 nm to 430 nm were obtained, which is wider than that of QDs obtained in a traditional flask without changing halide component. The mechanism of photoluminescence (PL) spectral shift of CsPbBr₃ QDs was investigated, the result shows that the supersaturation control enabled by the superior mass and heat transfer performance in the microchannel is the key to achieve the wide range of PL spectrum, with only a change in the setting of the temperature controller required. The wide spectrum of CsPbBr₃ QDs can be applied to light-emitting diodes (LEDs), photoelectric sensors, lasers, etc.

Study of the disorder by means of the superconducting penetration depth

International Nuclear Information System (INIS)

Arce, R.D.

1982-11-01

Measurements of the weak magnetic field penetration depth in the amorphous superconducting systems Lasub(1-x) Msub(x), being M = Cu, Al, Ga and Au, and in the Zr 70 Cu 30 system are presented. Measurements of the sample geometrical factors and the flux expulsion between the lowest temperature reached and the critical temperature, allows the determination of zero temperature penetration depth. The measurement of the flux expulsion as a function of temperature is used to determine the temperature dependence of penetration depth, used to evaluate the temperature dependence superconducting gap. The magnetization measurements have been made using an rf-SQUID. The evolution of the penetration depth with annealing is studied in the La 70 Cu 30 and Zr 70 Cu 30 systems. Measurements of the electrical resistivity and the critical temperature are used to verify the Gorkov equations in these materials. The variation of the penetration depth with annealing suggests that a metallurgical phase separation occurs within the submicrometer range. Penetration depth measurement is a tool to detect this type of phase separation in high kappa materials. (M.E.L.) [es

Phenomenon of quantum low temperature limit of chemical reaction rates

International Nuclear Information System (INIS)

Gol'danskij, V.I.

1975-01-01

The influence of quantum-mechanical effects on one of the fundamental laws of chemical kinetics - the Arrhenius law - is considered. Criteria characterising the limits of the low-temperature region where the extent of quantum-mechanical tunnelling transitions exceeds exponentially the transitions over the barrier are quoted. Studies of the low-temperature tunnelling of electrons and hydrogen atoms are briefly mentioned and the history of research on low-temperature radiation-induced solid-phase polymerisation, the development of which led to the discovery of the phenomenon of the low-temperature quantum-mechanical limit for the rates of chemical reactions in relation to the formaldehyde polymerisation reaction, is briefly considered. The results of experiments using low-inertia calorimeters, whereby it is possible to determine directly the average time (tau 0 ) required to add one new link to the polymer chain of formaldehyde during its polymerisation by radiation and during postpolymerisation and to establish that below 80K the increase of tau 0 slows down and that at T approximately equal to 10-4K the time tau 0 reaches a plateau (tau 0 approximately equals 0.01s), are described. Possible explanations of the observed low-temperature limit for the rate of a chemical reaction are critically examined and a semiquantitative explanation is given for this phenomenon, which may be particularly common in combined electronic-confirmational transitions in complex biological molecules and may play a definite role in chemical and biological evolution (cold prehistory of life)

Phenomenon of quantum low temperature limit of chemical reaction rates

Energy Technology Data Exchange (ETDEWEB)

Gol' danskii, V I [AN SSSR, Moscow. Inst. Khimicheskoj Fiziki

1975-12-01

The influence of quantum-mechanical effects on one of the fundamental laws of chemical kinetics - the Arrhenius Law - is considered. Criteria characterising the limits of the low-temperature region where the extent of quantum-mechanical tunnelling transitions exceeds exponentially the transitions over the barrier are quoted. Studies of the low-temperature tunnelling of electrons and hydrogen atoms are briefly mentioned and the history of research on low-temperature radiation-induced solid-phase polymerization, the development of which led to the discovery of the phenomenon of the low-temperature quantum-mechanical limit for the rates of chemical reactions in relation to the formaldehyde polymerization reaction, is briefly considered. The results of experiments using low-inertia calorimeters, whereby it is possible to determine directly the average time (tau/sub 0/) required to add one new link to the polymer chain of formaldehyde during its polymerization by radiation and during postpolymerization and to establish that below 80K the increase of tau/sub 0/ slows down and that at T approximately equal to 10-4K the time tau/sub 0/ reaches a plateau (tau/sub 0/ approximately equals 0.01s), are described. Possible explanations of the observed low-temperature limit for the rate of a chemical reaction are critically examined and a semiquantitative explanation is given for this phenomenon, which may be particularly common in combined electronic-confirmational transitions in complex biological molecules and may play a definite role in chemical and biological evolution (cold prehistory of life).

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across the Hawaiian Archipelago in 2013 (NCEI Accession 0161327)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

The Neutron Spectrum in a Uranium Tube

International Nuclear Information System (INIS)

Johansson, E.; Jonsson, E.; Lindberg, M.; Mednis, J.

1963-10-01

A series of experimental and theoretical investigations on neutron spectra in lattice cells has been started at the reactor R1. This report gives the results from the first one of these cells - one with a tube of natural -uranium surrounded by heavy water. In the measurements the cell was placed in the central, vertical channel of the reactor. The neutron spectrum from a lead scatterer in the uranium tube - outer diameter 49.2 mm, inner diameter 28.3 mm - was measured with a fast chopper in the energy region 0.01 to 100 eV. Subsidiary measurements indicated that the spectrum in the beam from the lead piece corresponds to the spectrum of the angular flux integrated over all angles. This correspondence is important for the interpretation of the experimental data. The thermal part of the spectrum was found to deviate significantly from a Maxwellian. However, the deviation is not very large, and one could use a Maxwellian, at least to give a rough idea of the hardness of the spectrum. For the present tube the temperature of this Maxwellian was estimated as 90 to 100 deg C above the moderator temperature (33 deg C). In the joining region the rise of the spectrum towards the thermal part is slower than for the cell boundary spectrum, measured earlier. In the epithermal region the limited resolution of the chopper has affected the measurements at the energies of the uranium resonances. However, the shape of the spectrum on the flanks of the first resonance in 238 U (6.68 eV) has been obtained accurately. In the theoretical treatment the THERMOS code with a free gas scattering model has been used. The energy region was 3.06 - 0.00025 eV. The agreement with the measurements is good for the thermal part - possibly the theoretical spectrum is a little softer than the experimental one. In the joining region the results from THERMOS are comparatively high - probably due to the scattering model used

The Neutron Spectrum in a Uranium Tube

Energy Technology Data Exchange (ETDEWEB)

Johansson, E; Jonsson, E; Lindberg, M; Mednis, J

1963-10-15

A series of experimental and theoretical investigations on neutron spectra in lattice cells has been started at the reactor R1. This report gives the results from the first one of these cells - one with a tube of natural -uranium surrounded by heavy water. In the measurements the cell was placed in the central, vertical channel of the reactor. The neutron spectrum from a lead scatterer in the uranium tube - outer diameter 49.2 mm, inner diameter 28.3 mm - was measured with a fast chopper in the energy region 0.01 to 100 eV. Subsidiary measurements indicated that the spectrum in the beam from the lead piece corresponds to the spectrum of the angular flux integrated over all angles. This correspondence is important for the interpretation of the experimental data. The thermal part of the spectrum was found to deviate significantly from a Maxwellian. However, the deviation is not very large, and one could use a Maxwellian, at least to give a rough idea of the hardness of the spectrum. For the present tube the temperature of this Maxwellian was estimated as 90 to 100 deg C above the moderator temperature (33 deg C). In the joining region the rise of the spectrum towards the thermal part is slower than for the cell boundary spectrum, measured earlier. In the epithermal region the limited resolution of the chopper has affected the measurements at the energies of the uranium resonances. However, the shape of the spectrum on the flanks of the first resonance in {sup 238}U (6.68 eV) has been obtained accurately. In the theoretical treatment the THERMOS code with a free gas scattering model has been used. The energy region was 3.06 - 0.00025 eV. The agreement with the measurements is good for the thermal part - possibly the theoretical spectrum is a little softer than the experimental one. In the joining region the results from THERMOS are comparatively high - probably due to the scattering model used.

The Atacama Cosmology Telescope: temperature and gravitational lensing power spectrum measurements from three seasons of data

Energy Technology Data Exchange (ETDEWEB)

Das, Sudeep [Argonne National Laboratory, 9700 S. Cass Ave., Lemont, IL 60439 (United States); Louis, Thibaut; Calabrese, Erminia; Dunkley, Joanna [Sub-department of Astrophysics, University of Oxford, Keble Road, Oxford, OX1 3RH (United Kingdom); Nolta, Michael R.; Bond, J Richard; Hajian, Amir; Hincks, Adam D. [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON, M5S 3H8 Canada (Canada); Addison, Graeme E.; Halpern, Mark [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z4 Canada (Canada); Battistelli, Elia S. [Department of Physics, University of Rome ' ' La Sapienza' ' , Piazzale Aldo Moro 5, I-00185 Rome (Italy); Crichton, Devin; Gralla, Megan [Dept. of Physics and Astronomy, The Johns Hopkins University, 3400 N. Charles St., Baltimore, MD 21218-2686 (United States); Devlin, Mark J.; Dicker, Simon [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA, 19104 (United States); Dünner, Rolando [Departamento de Astronomía y Astrofísica, Facultad de Física, Pontificía Universidad Católica, Casilla 306, Santiago 22 (Chile); Fowler, Joseph W. [NIST Quantum Devices Group, 325 Broadway Mailcode 817.03, Boulder, CO, 80305 (United States); Hasselfield, Matthew; Hlozek, Renée [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Hilton, Matt, E-mail: sudeepphys@gmail.com [Centre for Astronomy and Particle Theory, School of Physics and Astronomy, University of Nottingham, NG7 2RD (United Kingdom); and others

2014-04-01

We present the temperature power spectra of the cosmic microwave background (CMB) derived from the three seasons of data from the Atacama Cosmology Telescope (ACT) at 148 GHz and 218 GHz, as well as the cross-frequency spectrum between the two channels. We detect and correct for contamination due to the Galactic cirrus in our equatorial maps. We present the results of a number of tests for possible systematic error and conclude that any effects are not significant compared to the statistical errors we quote. Where they overlap, we cross-correlate the ACT and the South Pole Telescope (SPT) maps and show they are consistent. The measurements of higher-order peaks in the CMB power spectrum provide an additional test of the ΛCDM cosmological model, and help constrain extensions beyond the standard model. The small angular scale power spectrum also provides constraining power on the Sunyaev-Zel'dovich effects and extragalactic foregrounds. We also present a measurement of the CMB gravitational lensing convergence power spectrum at 4.6σ detection significance.

The Atacama Cosmology Telescope: Temperature and Gravitational Lensing Power Spectrum Measurements from Three Seasons of Data

Science.gov (United States)

Das, Sudeep; Louis, Thibaut; Nolta, Michael R.; Addison, Graeme E.; Battisetti, Elia S.; Bond, J. Richard; Calabrese, Erminia; Crichton, Devin; Devlin, Mark J.; Dicker, Simon;

The Atacama Cosmology Telescope: temperature and gravitational lensing power spectrum measurements from three seasons of data

International Nuclear Information System (INIS)

Das, Sudeep; Louis, Thibaut; Calabrese, Erminia; Dunkley, Joanna; Nolta, Michael R.; Bond, J Richard; Hajian, Amir; Hincks, Adam D.; Addison, Graeme E.; Halpern, Mark; Battistelli, Elia S.; Crichton, Devin; Gralla, Megan; Devlin, Mark J.; Dicker, Simon; Dünner, Rolando; Fowler, Joseph W.; Hasselfield, Matthew; Hlozek, Renée; Hilton, Matt

2014-01-01

We present the temperature power spectra of the cosmic microwave background (CMB) derived from the three seasons of data from the Atacama Cosmology Telescope (ACT) at 148 GHz and 218 GHz, as well as the cross-frequency spectrum between the two channels. We detect and correct for contamination due to the Galactic cirrus in our equatorial maps. We present the results of a number of tests for possible systematic error and conclude that any effects are not significant compared to the statistical errors we quote. Where they overlap, we cross-correlate the ACT and the South Pole Telescope (SPT) maps and show they are consistent. The measurements of higher-order peaks in the CMB power spectrum provide an additional test of the ΛCDM cosmological model, and help constrain extensions beyond the standard model. The small angular scale power spectrum also provides constraining power on the Sunyaev-Zel'dovich effects and extragalactic foregrounds. We also present a measurement of the CMB gravitational lensing convergence power spectrum at 4.6σ detection significance

New upper limits for atmospheric constituents on Io

Science.gov (United States)

Fink, U.; Larson, H. P.; Gautier, T. N., III

1976-01-01

A spectrum of Io from 0.86 to 2.7 microns with a resolution of 3.36 per cm and a signal to rms noise ratio of 120 is presented. No absorptions due to any atmospheric constituents on Io could be found in the spectrum. Upper limits of 0.12 cm-atm for NH3, 0.12 cm-atm for CH4, 0.4 cm-atm for N2O, and 24 cm-atm for H2S were determined. Laboratory spectra of ammonia frosts as a function of temperature were compared with the spectrum of Io and showed this frost not to be present at the surface of Io. A search for possible resonance lines of carbon, silicon, and sulfur, as well as the 1.08-micron line of helium, proved negative. Upper emission limits of 60, 18, 27, and 60 kilorayleighs, respectively, were established for these lines.

Relation between Wet-Bulb Globe Temperature and Thermal Work Limit Indices with Body Core Temperature

Directory of Open Access Journals (Sweden)

Mahdi Jalali

2018-06-01

Full Text Available Occupational exposure to heat stress in casting and smelting industries can cause adverse health effects on employees who working in such industries. The present study was set to assess the correlation and agreement of heat stress indices, including wet bulb globe temperature (WBGT, and thermal work limit (TWL, and the deep body temperature indices in workers of several casting and smelting industries located in the vicinity of Tehran, Iran. In This cross-sectional study 40 workers randomly selected and were examined. WBGT and TWL were the indices used for assessing heat stress, and the tympanic temperature and the oral temperature were measured as the heat strain indices. The correlation and agreement of indices were measured using SPSS vs.16. The results of the assessment of WBGT, TWL, the tympanic temperature, and oral temperature showed that 80, 17.5, 40, and 32.5 percent of workers exposed to heat stress higher than permissible limits proposed by standard bodies. Moreover, the present study showed that the significant correlation coefficient between heat stress and heat strain indices was in the range of 0.844- 0.869. Further, there was observed a good agreement between TWL and heat strain indices. The agreement between TWL and the oral temperature was 0.63 (P-value≤ 0.001 and between TWL and tympanic temperature was 0.612 (P-value≤ 0.001. However, the agreement between WBGT and heat strain indices was not satisfactory. These values were 0.154 (P-value ≥ 0.068 and 0.215 (P-value≥ 0.028 for the oral temperature and the tympanic temperature, respectively. The TWL index had a better agreement than WBGT with heat strain indices so TWL index is the better choice for assessing the heat stress in casting and metal smelting industries.

Low temperature London penetration depth and superfluid density in Fe-based superconductors

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyunsoo [Iowa State Univ., Ames, IA (United States)

2013-01-01

The superconducting gap symmetry of the Fe-based superconductors was studied by measurements and analysis of London penetration depth and super uid density. Tunnel diode resonator technique for these measurements was implemented in a dilution refrigerator allowing for the temperatures down to 50 mK. For the analysis of the super uid density, we used both experimental studies of Al-coated samples and original thermodynamic approach based on Rutgers relation. In three systems studied, we found that the superconducting gap at the optimal doping is best described in multi-gap full gap scenario. By performing experiments on samples with arti cially introduced disorder with heavy ion irradiation, we show that evolution of the superconducting transition temperature and of the super uid density are consistent with full-gap sign changing s superconducting state. The superconducting gap develops strong modulation both in the under-doped and the over-doped regimes. In the terminal hole-doped KFe{sub 2}As{sub 2}, both temperature dependence of the super uid density and its evolution with increase of the scattering rate are consistent with symmetry imposed vertical line nodes in the superconducting gap. By comparative studies of hole-doped (Ba,K)Fe{sub 2}As{sub 2} and electron-doped Ca10-3-8, we show that the superconducting gap modulation in the under-doped regime is intrinsic and is not induced by the coexisting static magnetic order.

Upper limits on the 21 cm power spectrum at z = 5.9 from quasar absorption line spectroscopy

Science.gov (United States)

Pober, Jonathan C.; Greig, Bradley; Mesinger, Andrei

2016-11-01

We present upper limits on the 21 cm power spectrum at z = 5.9 calculated from the model-independent limit on the neutral fraction of the intergalactic medium of x_{H I} chain Monte Carlo Epoch of Reionization analysis code, we explore the probability distribution of 21 cm power spectra consistent with this constraint on the neutral fraction. We present 99 per cent confidence upper limits of Δ2(k) limit dependent on the sampled k mode. This limit can be used as a null test for 21 cm experiments: a detection of power at z = 5.9 in excess of this value is highly suggestive of residual foreground contamination or other systematic errors affecting the analysis.

Soil temperature modeling at different depths using neuro-fuzzy, neural network, and genetic programming techniques

Science.gov (United States)

Kisi, Ozgur; Sanikhani, Hadi; Cobaner, Murat

2017-08-01

The applicability of artificial neural networks (ANN), adaptive neuro-fuzzy inference system (ANFIS), and genetic programming (GP) techniques in estimating soil temperatures (ST) at different depths is investigated in this study. Weather data from two stations, Mersin and Adana, Turkey, were used as inputs to the applied models in order to model monthly STs. The first part of the study focused on comparison of ANN, ANFIS, and GP models in modeling ST of two stations at the depths of 10, 50, and 100 cm. GP was found to perform better than the ANN and ANFIS-SC in estimating monthly ST. The effect of periodicity (month of the year) on models' accuracy was also investigated. Including periodicity component in models' inputs considerably increased their accuracies. The root mean square error (RMSE) of ANN models was respectively decreased by 34 and 27 % for the depths of 10 and 100 cm adding the periodicity input. In the second part of the study, the accuracies of the ANN, ANFIS, and GP models were compared in estimating ST of Mersin Station using the climatic data of Adana Station. The ANN models generally performed better than the ANFIS-SC and GP in modeling ST of Mersin Station without local climatic inputs.

Relationships between junction temperature, electroluminescence spectrum and ageing of light-emitting diodes

Science.gov (United States)

Vaskuri, Anna; Kärhä, Petri; Baumgartner, Hans; Kantamaa, Olli; Pulli, Tomi; Poikonen, Tuomas; Ikonen, Erkki

2018-04-01

We have developed spectral models describing the electroluminescence spectra of AlGaInP and InGaN light-emitting diodes (LEDs) consisting of the Maxwell-Boltzmann distribution and the effective joint density of states. One spectrum at a known temperature for one LED specimen is needed for calibrating the model parameters of each LED type. Then, the model can be used for determining the junction temperature optically from the spectral measurement, because the junction temperature is one of the free parameters. We validated the models using, in total, 53 spectra of three red AlGaInP LED specimens and 72 spectra of three blue InGaN LED specimens measured at various current levels and temperatures between 303 K and 398 K. For all the spectra of red LEDs, the standard deviation between the modelled and measured junction temperatures was only 2.4 K. InGaN LEDs have a more complex effective joint density of states. For the blue LEDs, the corresponding standard deviation was 11.2 K, but it decreased to 3.5 K when each LED specimen was calibrated separately. The method of determining junction temperature was further tested on white InGaN LEDs with luminophore coating and LED lamps. The average standard deviation was 8 K for white InGaN LED types. We have six years of ageing data available for a set of LED lamps and we estimated the junction temperatures of these lamps with respect to their ageing times. It was found that the LEDs operating at higher junction temperatures were frequently more damaged.

Determining clinical photon beam spectra from measured depth dose with the Cimmino algorithm

International Nuclear Information System (INIS)

Bloch, P.; Altschuler, M.D.; Bjaerngard, B.E.; Kassaee, A.; McDonough, J.

2000-01-01

A method to determine the spectrum of a clinical photon beam from measured depth-dose data is described. At shallow depths, where the range of Compton-generated electrons increases rapidly with photon energy, the depth dose provides the information to discriminate the spectral contributions. To minimize the influence of contaminating electrons, small (6x6cm2 ) fields were used. The measured depth dose is represented as a linear combination of basis functions, namely the depth doses of monoenergetic photon beams derived by Monte Carlo simulations. The weights of the basis functions were obtained with the Cimmino feasibility algorithm, which examines in each iteration the discrepancy between predicted and measured depth dose. For 6 and 15 MV photon beams of a clinical accelerator, the depth dose obtained from the derived spectral weights was within about 1% of the measured depth dose at all depths. Because the problem is ill conditioned, solutions for the spectrum can fluctuate with energy. Physically realistic smooth spectra for these photon beams appeared when a small margin (about ±1%) was attributed to the measured depth dose. The maximum energy of both derived spectra agreed with the measured energy of the electrons striking the target to within 1 MeV. The use of a feasibility method on minimally relaxed constraints provides realistic spectra quickly and interactively. (author)

An observation-based assessment of the influences of air temperature and snow depth on soil temperature in Russia

International Nuclear Information System (INIS)

Park, Hotaek; Sherstiukov, Artem B; Fedorov, Alexander N; Polyakov, Igor V; Walsh, John E

2014-01-01

This study assessed trends in the variability of soil temperature (T SOIL ) using spatially averaged observation records from Russian meteorological land stations. The contributions of surface air temperature (SAT) and snow depth (SND) to T SOIL variation were quantitatively evaluated. Composite time series of these data revealed positive trends during the period of 1921–2011, with accelerated increases since the 1970s. The T SOIL warming rate over the entire period was faster than the SAT warming rate in both permafrost and non-permafrost regions, suggesting that SND contributes to T SOIL warming. Statistical analysis revealed that the highest correlation between SND and T SOIL was in eastern Siberia, which is underlain by permafrost. SND in this region accounted for 50% or more of the observed variation in T SOIL . T SOIL in the non-permafrost region of western Siberia was significantly correlated with changes in SAT. Thus, the main factors associated with T SOIL variation differed between permafrost and non-permafrost regions. This finding underscores the importance of including SND data when assessing historical and future variations and trends of permafrost in the Northern Hemisphere. (letter)

Temperature stability limits for an isothermal demagnetization refrigerator

Science.gov (United States)

Kittel, P.

1984-01-01

It is pointed out that magnetic refrigeration can provide additional cooling for infrared detectors on space missions, taking into account the Shuttle Infrared Telescope Facility (SIRTF) and the Large Deployable Reflector (LDR). From a temperature of 2 K provided by the primary cryogens, magnetic refrigerators could cool bolometers or pumped photoconductors to 0.1 K or below. Such a reduction in operating temperature would increase the sensitivity for bolometers, while the response at longer wavelengths for pumped photoconductors would be improved. Two types of magnetic refrigeration cycles have been proposed. One type uses a complete demagnetization. The present investigation is concerned with the second type, which uses a feedback-controlled isothermal demagnetization, taking into account the temperature stability limits. Attention is given to control system resolution, thermometer noise, reaction time, and thermal time constants.

Modelling the evolution of composition-and stress-depth profiles in austenitic stainless steels during low-temperature nitriding

DEFF Research Database (Denmark)

Jespersen, Freja Nygaard; Hattel, Jesper Henri; Somers, Marcel A. J.

2016-01-01

. In the present paper solid mechanics was combined with thermodynamics and diffusion kinetics to simulate the evolution of composition-depth and stress-depth profiles resulting from nitriding. The model takes into account a composition-dependent diffusion coefficient of nitrogen in expanded austenite, short range......Nitriding of stainless steel causes a surface zone of expanded austenite, which improves the wear resistance of the stainless steel while preserving the stainless behaviour. During nitriding huge residual stresses are introduced in the treated zone, arising from the volume expansion...... that accompanies the dissolution of high nitrogen contents in expanded austenite. An intriguing phenomenon during low-temperature nitriding is that the residual stresses evoked by dissolution of nitrogen in the solid state, affect the thermodynamics and the diffusion kinetics of nitrogen dissolution...

Regulating the Emission Spectrum of CsPbBr3 from Green to Blue via Controlling the Temperature and Velocity of Microchannel Reactor

Science.gov (United States)

Tang, Yong; Lu, Hanguang; Rao, Longshi; Ding, Xinrui; Yan, Caiman; Yu, Binhai

2018-01-01

The ability to precisely obtain tunable spectrum of lead halide perovskite quantum dots (QDs) is very important for applications, such as in lighting and display. Herein, we report a microchannel reactor method for synthesis of CsPbBr3 QDs with tunable spectrum. By adjusting the temperature and velocity of the microchannel reactor, the emission peaks of CsPbBr3 QDs ranging from 520 nm to 430 nm were obtained, which is wider than that of QDs obtained in a traditional flask without changing halide component. The mechanism of photoluminescence (PL) spectral shift of CsPbBr3 QDs was investigated, the result shows that the supersaturation control enabled by the superior mass and heat transfer performance in the microchannel is the key to achieve the wide range of PL spectrum, with only a change in the setting of the temperature controller required. The wide spectrum of CsPbBr3 QDs can be applied to light-emitting diodes (LEDs), photoelectric sensors, lasers, etc. PMID:29498710

Preferred temperature and thermal breadth of birds wintering in peninsular Spain: the limited effect of temperature on species distribution

Directory of Open Access Journals (Sweden)

Luis M. Carrascal

2016-07-01

Full Text Available Background. The availability of environmental energy, as measured by temperature, is expected to limit the abundance and distribution of endotherms wintering at temperate latitudes. A prediction of this hypothesis is that birds should attain their highest abundances in warmer areas. However, there may be a spatial mismatch between species preferred habitats and species preferred temperatures, so some species might end-up wintering in sub-optimal thermal environments. Methods. We model the influence of minimum winter temperature on the relative abundance of 106 terrestrial bird species wintering in peninsular Spain, at 10 ×10 km2 resolution, using 95%-quantile regressions. We analyze general trends across species on the shape of the response curves, the environmental preferred temperature (at which the species abundance is maximized, the mean temperature in the area of distribution and the thermal breadth (area under the abundance-temperature curve. Results. Temperature explains a low proportion of variation in abundance. The most significant effect is on limiting the maximum potential abundance of species. Considering this upper-limit response, there is a large interspecific variability on the thermal preferences and specialization of species. Overall, there is a preponderance of positive relationships between species abundance and temperature; on average, species attain their maximum abundances in areas 1.9 °C warmer than the average temperature available in peninsular Spain. The mean temperature in the area of distribution is lower than the thermal preferences of the species. Discussion. Many species prefer the warmest areas to overwinter, which suggests that temperature imposes important restrictions to birds wintering in the Iberian Peninsula. However, one third of species overwinter in locations colder than their thermal preferences, probably reflecting the interaction between habitat and thermal requirements. There is a high inter

Statistical moments of the angular spectrum of normal waves in a turbulent collisional magnetized plasma

International Nuclear Information System (INIS)

Aistov, A.V.; Gavrilenko, V.G.

1996-01-01

The normal incidence of a small-amplitude electromagnetic wave upon a semi-infinite turbulent collisional plasm with an oblique external magnetic field is considered. Within a small-angle-scattering approximation of the radiative transport theory, a system of differential equations is derived for statistical moments of the angular power spectrum of radiation. The dependences of the spectrum centroid, dispersion, and asymmetry on the depth of penetration are studied numerically. The nonmonotonic behavior of the dispersion is revealed, and an increase in the spectrum width with absorption anisotropy is found within some depth interval. It is shown that, at large depths, the direction of the displacement of the spectrum centroid, does not always coincide with the direction of minimum absorption

Experimental Observation of the Stratified Electrothermal Instability on Aluminum with Thickness Greater than a Skin Depth

Energy Technology Data Exchange (ETDEWEB)

Hutchinson, Trevor M. [Univ. of Nevada, Reno, NV (United States); Hutchinson, Trevor M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Awe, Thomas James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bauer, Bruno S. [Univ. of Nevada, Reno, NV (United States); Yates, Kevin [Univ. of New Mexico, Albuquerque, NM (United States); Yu, Edmund p. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Yelton, William G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Fuelling, Stephan [Univ. of Nevada, Reno, NV (United States)

2017-07-01

The first direct observation of the stratified electrothermal instability on the surface of thick metal is reported. Aluminum rods coated with 70 μm Parylene-N were driven to 1 MA in approximately 100 ns, with the metal thicker than the skin depth. The dielectric coating suppressed plasma formation, enabling persistent observation of discrete azimuthally-correlated stratified structures perpendicular to the current. Strata amplitudes grow rapidly, while their Fourier spectrum shifts toward longer wavelength. Assuming blackbody emission, radiometric calculations indicate strata are temperature perturbations that grow exponentially with rate γ = 0.04 ns -1 in 3000- 10,000 K aluminum.

Planck early results. XIX. All-sky temperature and dust optical depth from Planck and IRAS. Constraints on the "dark gas" in our Galaxy

DEFF Research Database (Denmark)

Poutanen, T.; Natoli, P.; Polenta, G.

2011-01-01

An all sky map of the apparent temperature and optical depth of thermal dust emission is constructed using the Planck-HFI (350μm to 2 mm) andIRAS(100μm) data. The optical depth maps are correlated with tracers of the atomic (Hi) and molecular gas traced by CO. The correlation with the column dens...

Water vapor in the spectrum of the extrasolar planet HD 189733b. I. The transit

International Nuclear Information System (INIS)

McCullough, P. R.; Crouzet, N.; Deming, D.; Madhusudhan, N.

2014-01-01

We report near-infrared spectroscopy of the gas giant planet HD 189733b in transit. We used the Hubble Space Telescope Wide Field Camera 3 (HST WFC3) with its G141 grism covering 1.1 μm to 1.7 μm and spatially scanned the image across the detector at 2'' s –1 . When smoothed to 75 nm bins, the local maxima of the transit depths in the 1.15 μm and 1.4 μm water vapor features are, respectively, 83 ± 53 ppm and 200 ± 47 ppm greater than the local minimum at 1.3 μm. We compare the WFC3 spectrum with the composite transit spectrum of HD 189733b assembled by Pont et al., extending from 0.3 μm to 24 μm. Although the water vapor features in the WFC3 spectrum are compatible with the model of non-absorbing, Rayleigh-scattering dust in the planetary atmosphere, we also re-interpret the available data with a clear planetary atmosphere. In the latter interpretation, the slope of increasing transit depth with shorter wavelengths from the near infrared, through the visible, and into the ultraviolet is caused by unocculted star spots, with a smaller contribution of Rayleigh scattering by molecular hydrogen in the planet's atmosphere. At relevant pressures along the terminator, our model planetary atmosphere's temperature is ∼700 K, which is below the condensation temperatures of sodium- and potassium-bearing molecules, causing the broad wings of the spectral lines of Na I and K I at 0.589 μm and 0.769 μm to be weak.

Water vapor in the spectrum of the extrasolar planet HD 189733b. I. The transit

Energy Technology Data Exchange (ETDEWEB)

McCullough, P. R.; Crouzet, N. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Deming, D. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Madhusudhan, N., E-mail: pmcc@stsci.edu [Yale Center for Astronomy and Astrophysics, Yale University, New Haven, CT 06511 (United States)

2014-08-10

We report near-infrared spectroscopy of the gas giant planet HD 189733b in transit. We used the Hubble Space Telescope Wide Field Camera 3 (HST WFC3) with its G141 grism covering 1.1 μm to 1.7 μm and spatially scanned the image across the detector at 2'' s{sup –1}. When smoothed to 75 nm bins, the local maxima of the transit depths in the 1.15 μm and 1.4 μm water vapor features are, respectively, 83 ± 53 ppm and 200 ± 47 ppm greater than the local minimum at 1.3 μm. We compare the WFC3 spectrum with the composite transit spectrum of HD 189733b assembled by Pont et al., extending from 0.3 μm to 24 μm. Although the water vapor features in the WFC3 spectrum are compatible with the model of non-absorbing, Rayleigh-scattering dust in the planetary atmosphere, we also re-interpret the available data with a clear planetary atmosphere. In the latter interpretation, the slope of increasing transit depth with shorter wavelengths from the near infrared, through the visible, and into the ultraviolet is caused by unocculted star spots, with a smaller contribution of Rayleigh scattering by molecular hydrogen in the planet's atmosphere. At relevant pressures along the terminator, our model planetary atmosphere's temperature is ∼700 K, which is below the condensation temperatures of sodium- and potassium-bearing molecules, causing the broad wings of the spectral lines of Na I and K I at 0.589 μm and 0.769 μm to be weak.

Analysis of SMOS brightness temperature and vegetation optical depth data with coupled land surface and radiative transfer models in Southern Germany

Directory of Open Access Journals (Sweden)

F. Schlenz

2012-10-01

Full Text Available Soil Moisture and Ocean Salinity (SMOS L1c brightness temperature and L2 optical depth data are analysed with a coupled land surface (PROMET and radiative transfer model (L-MEB. The coupled models are validated with ground and airborne measurements under contrasting soil moisture, vegetation and land surface temperature conditions during the SMOS Validation Campaign in May and June 2010 in the SMOS test site Upper Danube Catchment in southern Germany. The brightness temperature root-mean-squared errors are between 6 K and 9 K. The L-MEB parameterisation is considered appropriate under local conditions even though it might possibly be further optimised. SMOS L1c brightness temperature data are processed and analysed in the Upper Danube Catchment using the coupled models in 2011 and during the SMOS Validation Campaign 2010 together with airborne L-band brightness temperature data. Only low to fair correlations are found for this comparison (R between 0.1–0.41. SMOS L1c brightness temperature data do not show the expected seasonal behaviour and are positively biased. It is concluded that RFI is responsible for a considerable part of the observed problems in the SMOS data products in the Upper Danube Catchment. This is consistent with the observed dry bias in the SMOS L2 soil moisture products which can also be related to RFI. It is confirmed that the brightness temperature data from the lower SMOS look angles and the horizontal polarisation are less reliable. This information could be used to improve the brightness temperature data filtering before the soil moisture retrieval. SMOS L2 optical depth values have been compared to modelled data and are not considered a reliable source of information about vegetation due to missing seasonal behaviour and a very high mean value. A fairly strong correlation between SMOS L2 soil moisture and optical depth was found (R = 0.65 even though the two variables are considered independent in the

Prototype development or multi-cavity ion chamber for depth dose measurement

International Nuclear Information System (INIS)

Nayak, M.K.; Sahu, T.K.; Haridas, G.; Bandyopadhyay, Tapas; Tripathi, R.M.; Nandedkar, R.V.

2016-01-01

In high energy electron accelerators, when the electrons interact with vacuum chamber or surrounding structural material, Bremsstrahlung x-rays are produced. It is having a broad spectrum extending up to the electron energies. Dose measured as a function of depth due to electromagnetic cascade will give rise to depth dose curve. To measure the online depth dose profile in an absorber medium, when high energy electron or Bremsstrahlung is incident, a prototype Multi-Cavity Ion Chamber (MCIC) detector is developed. The paper describes the design and development of the MCIC for measurement of depth dose profile

Irradiation spectrum and ionization-induced diffusion effects in ceramics

Energy Technology Data Exchange (ETDEWEB)

Zinkle, S.J. [Oak Ridge National Lab., TN (United States)

1997-08-01

There are two main components to the irradiation spectrum which need to be considered in radiation effects studies on nonmetals, namely the primary knock-on atom energy spectrum and ionizing radiation. The published low-temperature studies on Al{sub 2}O{sub 3} and MgO suggest that the defect production is nearly independent of the average primary knock-on atom energy, in sharp contrast to the situation for metals. On the other hand, ionizing radiation has been shown to exert a pronounced influence on the microstructural evolution of both semiconductors and insulators under certain conditions. Recent work on the microstructure of ion-irradiated ceramics is summarized, which provides evidence for significant ionization-induced diffusion. Polycrystalline samples of MgO, Al{sub 2}O{sub 3}, and MgAl{sub 2}O{sub 4} were irradiated with various ions ranging from 1 MeV H{sup +} to 4 MeV Zr{sup +} ions at temperatures between 25 and 650{degrees}C. Cross-section transmission electron microscopy was used to investigate the depth-dependent microstructural of the irradiated specimens. Dislocation loop nucleation was effectively suppressed in specimens irradiated with light ions, whereas the growth rate of dislocation loops was enhanced. The sensitivity to irradiation spectrum is attributed to ionization-induced diffusion. The interstitial migration energies in MgAl{sub 2}O{sub 4} and Al{sub 2}O{sub 3} are estimated to be {le}0.4 eV and {le}0.8 eV, respectively for irradiation conditions where ionization-induced diffusion effects are expected to be negligible.

Broadband seismic noise attenuation versus depth at the Albuquerque Seismological Laboratory

Science.gov (United States)

Hutt, Charles R.; Ringler, Adam; Gee, Lind

2017-01-01

Seismic noise induced by atmospheric processes such as wind and pressure changes can be a major contributor to the background noise observed in many seismograph stations, especially those installed at or near the surface. Cultural noise such as vehicle traffic or nearby buildings with air handling equipment also contributes to seismic background noise. Such noise sources fundamentally limit our ability to resolve earthquake‐generated signals. Many previous seismic noise versus depth studies focused separately on either high‐frequency (>1  Hz">>1  Hz) or low‐frequency (shallow surface vaults) up to 100 m or more (boreholes) in the permanent observatories of the Global Seismographic Network (GSN). It is important for managers and planners of these and similar arrays and networks of seismograph stations to understand the attenuation of surface‐generated noise versus depth so that they can achieve desired performance goals within their budgets as well as their frequency band of focus. The results of this study will assist in decisions regarding BB and VBB seismometer installation depths. In general, we find that greater installation depths are better and seismometer emplacement in hard rock is better than in soil. Attenuation for any given depth varies with frequency. More specifically, we find that the dependence of depth will be application dependent based on the frequency band and sensitive axes of interest. For quick deployments (like aftershock studies), 1 m may be deep enough to produce good data, especially when the focus is on vertical data where temperature stability fundamentally limits the low‐frequency noise levels and little low‐frequency data will be used. For temporary (medium‐term) deployments (e.g., TA) where low cost can be very important, 2–3 m should be sufficient, but such shallow installations will limit the ability to resolve low‐frequency signals, especially on horizontal components. Of course, one should try for

[Study on plasma temperature of a large area surface discharge by optical emission spectrum].

Science.gov (United States)

Dong, Li-Fang; Tong, Guo-Liang; Zhang, Yu; Zhou, Bin

2014-04-01

A large area surface discharge was realized in air/argon gas mixture by designing a discharge device with water electrodes. By using optical emission spectrum, the variations of the molecular vibrational temperature, the mean energy of electron, and the electronic excitation temperature as a function of the gas pressure were studied. The nitrogen molecular vibrational temperature was calculated according to the emission line of the second positive band system of the nitrogen molecule (C3 pi(u) --> B 3 pi(g)). The electronic excitation temperature was obtained by using the intensity ratio of Ar I 763.51 nm (2P(6) --> 1S(5)) to Ar I 772.42 nm (2P(2) --> 1S(3)). The changes in the mean energy of electron were studied by the relative intensity ratio of the nitrogen molecular ion 391.4 nm to nitrogen 337.1 nm. It was found that the intensity of emission spectral line increases with the increase in the gas pressure, meanwhile, the outline and the ratios of different spectral lines intensity also change. The molecular vibrational temperature, the mean energy of electron, and the electronic excitation temperature decrease as the gas pressure increases from 0.75 x 10(5) Pa to 1 x 10(5) Pa.

Upper limit on the transition temperature for non-ideal Bose gases

International Nuclear Information System (INIS)

Dai Wusheng; Xie Mi

2007-01-01

In this paper, we show that for a non-ideal Bose gas there exists an upper limit on the transition temperature above which Bose-Einstein condensation cannot occur regardless of the pressure applied. Such upper limits for some realistic Bose gases are estimated

Cosmic microwave background dipole spectrum measured by the COBE FIRAS instrument

Science.gov (United States)

Fixsen, D. J.; Cheng, E. S.; Cottingham, D. A.; Eplee, R. E., Jr.; Isaacman, R. B.; Mather, J. C.; Meyer, S. S.; Noerdlinger, P. D.; Shafer, R. A.; Weiss, R.

1994-01-01

The Far-Infrared Absolute Spectrophotometer (FIRAS) instrument on the Cosmic Background Explorer (COBE) has determined the dipole spectrum of the cosmic microwave background radiation (CMBR) from 2 to 20/cm. For each frequency the signal is decomposed by fitting to a monopole, a dipole, and a Galactic template for approximately 60% of the sky. The overall dipole spectrum fits the derivative of a Planck function with an amplitude of 3.343 +/- 0.016 mK (95% confidence level), a temperature of 2.714 +/- 0.022 K (95% confidence level), and an rms deviation of 6 x 10(exp -9) ergs/sq cm/s/sr cm limited by a detector and cosmic-ray noise. The monopole temperature is consistent with that determined by direct measurement in the accompanying article by Mather et al.

Regulating the Emission Spectrum of CsPbBr3 from Green to Blue via Controlling the Temperature and Velocity of Microchannel Reactor

Directory of Open Access Journals (Sweden)

Yong Tang

2018-03-01

Full Text Available The ability to precisely obtain tunable spectrum of lead halide perovskite quantum dots (QDs is very important for applications, such as in lighting and display. Herein, we report a microchannel reactor method for synthesis of CsPbBr3 QDs with tunable spectrum. By adjusting the temperature and velocity of the microchannel reactor, the emission peaks of CsPbBr3 QDs ranging from 520 nm to 430 nm were obtained, which is wider than that of QDs obtained in a traditional flask without changing halide component. The mechanism of photoluminescence (PL spectral shift of CsPbBr3 QDs was investigated, the result shows that the supersaturation control enabled by the superior mass and heat transfer performance in the microchannel is the key to achieve the wide range of PL spectrum, with only a change in the setting of the temperature controller required. The wide spectrum of CsPbBr3 QDs can be applied to light-emitting diodes (LEDs, photoelectric sensors, lasers, etc.

The coefficient of friction of chrysotile gouge at seismogenic depths

Science.gov (United States)

Moore, Diane E.; Lockner, D.A.; Tanaka, H.; Iwata, K.

2004-01-01

We report new strength data for the serpentine mineral chrysotile at effective normal stresses, ??sn between 40 and 200 MPa in the temperature range 25??-280??C. Overall, the coefficient of friction, ?? (= shear stress/effective normal stress) of water-saturated chrysotile gouge increases both with increasing temperature and ??sn, but the rates vary and the temperature-related increases begin at ???100??C. As a result, a frictional strength minimum (?? = 0.1) occurs at low ??sn at about 100??C. Maximum strength (?? = 0.55) results from a combination of high normal stress and high temperature. The low-strength region is characterized by velocity strengthening and the high-strength region by velocity-weakening behavior. Thoroughly dried chrysotile has ?? = 0.7 and is velocity-weakening. The frictional properties of chrysolite can be explained in its tendency to adsorb large amounts of water that acts as a lubricant during shear. The water is progressively driven off the fiber surfaces with increasing temperature and pressure, causing chrysotile to approach its dry strength. Depth profiles for a chrysotile-lined fault constructed from these data would pass through a strength minimum at ???3 km depth, where sliding should be stable. Below that depth, strength increases rapidly as does the tendency for unstable (seismic) slip. Such a trend would not have been predicted from the room-temperature data. These results therefore illustrate the potential hazards of extrapolating room-temperature friction data to predict fault zone behavior at depth. This depth profile for chrysotile is consistent with the pattern of slip on the Hayward fault, which creeps aseismically at shallow depths but which may be locked below 5 km depth. ?? 2004 by V. H. Winston and Son, Inc. All rights reserved.

Machine-operated low temperature system for cooling a germanium detector at great depths of the sea

International Nuclear Information System (INIS)

Bruederle, F.; Hain, K.; Huebener, J.; Schloss, F.

1978-07-01

The report outlines the conceptual design and technical implementation phases of a very reliable low temperature system for long-time cooling of a germanium detector at great depths of the sea. The approach chosen as the solution involves the choise of a proven commercial small-scale refrigeration unit operation by the Gifford-Mc Mahon process, which is modified so as to suit special requirements. Testing for the severe conditions of use is carried out on a jarring table for the critical components and on a rolling test rig for the whole low temperature machine so as to simulate the stresses imposed by ships and high seas. The cooling system designed in this way has demonstrated its full functioning capability in a test conducted at sea. (orig.) 891 HP [de

The complete, temperature resolved experimental spectrum of methanol (CH{sub 3}OH) between 560 and 654 GHz

Energy Technology Data Exchange (ETDEWEB)

Fortman, Sarah M.; Neese, Christopher F.; De Lucia, Frank C., E-mail: fcd@mps.ohio-state.edu [Department of Physics, Ohio State University, 191 West Woodruff Avenue, Columbus, OH 43210 (United States)

2014-02-20

The complete spectrum of methanol (CH{sub 3}OH) has been characterized over a range of astrophysically significant temperatures in the 560.4-654.0 GHz spectral region. Absolute intensity calibration and analysis of 166 experimental spectra recorded over a slow 248-398 K temperature ramp provide a means for the simulation of the complete spectrum of methanol as a function of temperature. These results include contributions from v{sub t} = 3 and other higher states that are difficult to model via quantum mechanical (QM) techniques. They also contain contributions from the {sup 13}C isotopologue in terrestrial abundance. In contrast to our earlier work on semi-rigid species, such as ethyl cyanide and vinyl cyanide, significant intensity differences between these experimental values and those calculated by QM methods were found for many of the lines. Analysis of these differences shows the difficulty of the calculation of dipole matrix elements in the context of the internal rotation of the methanol molecule. These results are used to both provide catalogs in the usual line frequency, linestrength, and lower state energy format, as well as in a frequency point-by-point catalog that is particularly well suited for the characterization of blended lines.

Asymptotic diffusion limit of cell temperature discretisation schemes for thermal radiation transport

Energy Technology Data Exchange (ETDEWEB)

Smedley-Stevenson, Richard P., E-mail: richard.smedley-stevenson@awe.co.uk [AWE PLC, Aldermaston, Reading, Berkshire, RG7 4PR (United Kingdom); Department of Earth Science and Engineering, Imperial College London, SW7 2AZ (United Kingdom); McClarren, Ryan G., E-mail: rmcclarren@ne.tamu.edu [Department of Nuclear Engineering, Texas A & M University, College Station, TX 77843-3133 (United States)

2015-04-01

This paper attempts to unify the asymptotic diffusion limit analysis of thermal radiation transport schemes, for a linear-discontinuous representation of the material temperature reconstructed from cell centred temperature unknowns, in a process known as ‘source tilting’. The asymptotic limits of both Monte Carlo (continuous in space) and deterministic approaches (based on linear-discontinuous finite elements) for solving the transport equation are investigated in slab geometry. The resulting discrete diffusion equations are found to have nonphysical terms that are proportional to any cell-edge discontinuity in the temperature representation. Based on this analysis it is possible to design accurate schemes for representing the material temperature, for coupling thermal radiation transport codes to a cell centred representation of internal energy favoured by ALE (arbitrary Lagrange–Eulerian) hydrodynamics schemes.

Asymptotic diffusion limit of cell temperature discretisation schemes for thermal radiation transport

International Nuclear Information System (INIS)

Smedley-Stevenson, Richard P.; McClarren, Ryan G.

2015-01-01

This paper attempts to unify the asymptotic diffusion limit analysis of thermal radiation transport schemes, for a linear-discontinuous representation of the material temperature reconstructed from cell centred temperature unknowns, in a process known as ‘source tilting’. The asymptotic limits of both Monte Carlo (continuous in space) and deterministic approaches (based on linear-discontinuous finite elements) for solving the transport equation are investigated in slab geometry. The resulting discrete diffusion equations are found to have nonphysical terms that are proportional to any cell-edge discontinuity in the temperature representation. Based on this analysis it is possible to design accurate schemes for representing the material temperature, for coupling thermal radiation transport codes to a cell centred representation of internal energy favoured by ALE (arbitrary Lagrange–Eulerian) hydrodynamics schemes

The Unusual Moessbauer Spectrum of Beryl

International Nuclear Information System (INIS)

Viana, R. R.; Costa, G. M. da; Grave, E. de; Evangelista, H. J.; Stern, W. B.

2001-01-01

The Moessbauer spectra of several aquamarine samples have been obtained in the temperature range of 4.2-500 K. A common feature observed in all room-temperature spectra is the presence of an asymmetric Fe 2+ doublet (ΔE Q ∼2.7 mm/s, δ∼1.1 mm/s), with a very broad low-velocity peak. This asymmetry is not caused by preferred orientation since the spectrum collected under the magic angle did not show any difference in the line intensities, nor is it caused by the superposition of a Fe 3+ doublet. At 4.2 K the spectrum of a deep-blue beryl could be well fitted with three symmetrical doublets, with the major Fe 2+ doublet accounting for 87% of the total spectral area. At 14 K the symmetry remains, but at 30 K the low-velocity peak is again broad. Surprisingly, the spectrum at 500 K also shows a broad, but symmetrical doublet, with a clear splitting of the lines indicating the presence of at least two Fe 2+ components. The room-temperature spectrum obtained after the 500 K run shows the same features as before the heating. A meaningful fit for the room-temperature spectrum, as well as an explanation for the temperature dependence of the Moessbauer spectra, are discussed

Exploring the Temperature Dependent Solid-State ALC Spectrum of the C6H6Mu• Radical with Ab-Initio Simulation Techniques

Science.gov (United States)

Sturniolo, S.; Liborio, L.; Pratt, F. L.; Cottrell, S. P.; Jochym, D. B.; Montanari, B.

The longitudinal field Avoided Level Crossing (ALC) muon spectrum of crystalline benzene is found to exhibit multiple complex features that strongly depend on temperature. In this work, a number of different computational techniques were used in conjunction to explain this behavior. An overall picture emerges in which the spectrum appears to be the result of an interplay of multiple dynamical effects, both classical and quantum mechanical.

Simultaneous measurement of temperature and pressure by a single fiber Bragg grating with a broadened reflection spectrum.

Science.gov (United States)

Guo, Tuan; Qiao, Xueguang; Jia, Zhenan; Zhao, Qida; Dong, Xiaoyi

2006-05-01

Simultaneous measurement of temperature and pressure with a single fiber Bragg grating (FBG) based on a broadened reflection spectrum is proposed and experimentally demonstrated. A novel double-hole structure of a cantilever beam is designed, and a FBG is affixed on the nonuniform strain area of the cantilever beam. The Bragg reflection bandwidth is sensitive to the spatially gradient strain but is free from the spatially uniform temperature. The wavelength peak shift and the bandwidth broadening of the FBG with a change of temperature and pressure allow for simultaneous discrimination between the temperature and the pressure effects. Standard deviation errors of 1.4 degrees C and 1.8 kPa were obtained with temperature and pressure ranges of 20 degrees C-100 degrees C and 0-80 kPa, respectively. This novel and low-cost sensor approach has considerable potential applications for temperature-insensitive strain measurement.

Temperature dependence of the Raman spectrum of 1-(4-chlorophenyl)-3-(2-thienyl)prop-2-en-1-one

Science.gov (United States)

de Toledo, T. A.; da Costa, R. C.; Al-Maqtari, H. M.; Jamalis, J.; Pizani, P. S.

2017-06-01

The heterocyclic chalcone containing thiophene ring 1-(4-chlorophenyl)-3-(2-thienyl)prop-2-en-1-one, C13H9ClOS was synthesized and investigated using experimental techniques such as nuclear magnetic resonance (1H and 13C NMR), Fourier transform infrared spectroscopy (FTIR) at room temperature, differential scanning calorimeter (DSC) from room temperature to 500 K and Raman scattering at the temperature range 10-413 K in order to study its structure and vibrational properties as well as stability and possible phase transition. Density functional theory (DFT) calculations were performed to determine the vibrational spectrum viewing to improve the knowledge of the material properties. A reasonable agreement was observed between theoretical and experimental Raman spectrum taken at 10 K since anharmonic effects of the molecular motion is reduced at low temperatures, leading to a more comprehensive assignment of the vibrational modes. Increasing the temperature up to 393 K, was observed the typical phonon anharmonicity behavior associated to changes in the Raman line intensities, line-widths and red-shift, in special in the external mode region, whereas the internal modes region remains almost unchanged due its strong chemical bonds. Furthermore, C13H9ClOS goes to melting phase transition in the temperature range 393-403 K and then sublimates in the temperature range 403-413 K. This is denounced by the disappearance of the external modes and the absence of internal modes in the Raman spectra, in accordance with DSC curve. The enthalpy (ΔH) obtained from the integration of the endothermic peak in DSC curve centered at 397 K is founded to be 121.5 J/g.

Low-temperature operating regime of the tokamak evacuating limiter

International Nuclear Information System (INIS)

Tokar', M.Z.

1987-01-01

The conditions for realizing the regime of strong recycling of a cold dense plasma of an evacuating limiter were determined based on a previously proposed model for describing the limiter layer of a tokamak. The scaling for the dependence of the gas pressure in the evacuation system on the average plasma density in the limiter layer was found, and agreed quantitatively with the results of measurements on the Alcator and ISX-B tokamaks. For the tokamak reactor of the INTOR scale the calculations show that the low-temperature operating regime of the evacuating limiter can be realized with a quite low pumping rate. It has the advantages of reduced erosion of the limiter and small fluxes of impurities into the working volume of the reactor. In addition, the relative concentration of the helium ash in the limiter layer does not exceed 2-3%, but the density of the main plasma is comparable to the proposed average density in the reactor. The concept of a stochastic limiter is of interest for lowering the plasma density in the limiter layer and lowering the thermal loads on the limiter

Gamma-ray emission spectrum from thermonuclear fusion reactions without intrinsic broadening

DEFF Research Database (Denmark)

Nocente, M.; Källne, J.; Salewski, Mirko

2015-01-01

First principle calculations of the gamma-ray energy spectrum arising from thermonuclear reactions without intrinsic broadening in fusion plasmas are presented, extending the theoretical framework needed to interpret measurements up to the accuracy level enabled by modern high resolution instrume......First principle calculations of the gamma-ray energy spectrum arising from thermonuclear reactions without intrinsic broadening in fusion plasmas are presented, extending the theoretical framework needed to interpret measurements up to the accuracy level enabled by modern high resolution...... instruments. An analytical formula for the spectrum from Maxwellian plasmas, which extends to higher temperatures than the results previously available in the literature, has been derived and used to discuss the assumptions and limitations of earlier models. In case of radio-frequency injection, numerical...... results based on a Monte Carlo method are provided, focusing in particular on improved relations between the peak shift and width from the reaction and the temperature of protons accelerated by radio-frequency heating.The results presented in this paper significantly improve the accuracy of diagnostic...

Performance analysis of distributed beamforming in a spectrum sharing system

KAUST Repository

Yang, Liang; Alouini, Mohamed-Slim; Qaraqe, Khalid A.

2012-01-01

In this paper, we consider a distributed beamforming scheme (DBF) in a spectrum sharing system where multiple secondary users share the spectrum with the licensed primary users under an interference temperature constraint. We assume that DBF is applied at the secondary users. We first consider optimal beamforming and compare it with the user selection scheme in terms of the outage probability and bit-error rate performance. Since perfect feedback is difficult to obtain, we then investigate a limited feedback DBF scheme and develop an outage probability analysis for a random vector quantization (RVQ) design algorithm. Numerical results are provided to illustrate our mathematical formalism and verify our analysis. © 2012 IEEE.

Performance analysis of distributed beamforming in a spectrum sharing system

KAUST Repository

Yang, Liang

2012-09-01

In this paper, we consider a distributed beamforming scheme (DBF) in a spectrum sharing system where multiple secondary users share the spectrum with the licensed primary users under an interference temperature constraint. We assume that DBF is applied at the secondary users. We first consider optimal beamforming and compare it with the user selection scheme in terms of the outage probability and bit-error rate performance. Since perfect feedback is difficult to obtain, we then investigate a limited feedback DBF scheme and develop an outage probability analysis for a random vector quantization (RVQ) design algorithm. Numerical results are provided to illustrate our mathematical formalism and verify our analysis. © 2012 IEEE.

Method for the determination of technical specifications limiting temperature in EBR-II operation

International Nuclear Information System (INIS)

Chang, L.K.; Hill, D.J.; Ku, J.Y.

1994-01-01

The methodology and analysis procedure to qualify the Mark-V and Mark-VA fuels for the Experimental Breeder Reactor II are summarized in this paper. Fuel performance data and design safety criteria are essential for thermal-hydraulic analysis and safety evaluations. Normal and off-normal operation duty cycles and transient classifications are required for the safety assessment of the fuels. The temperature limits of subassemblies were first determined by a steady-state thermal-structural and fuel damage analysis, in which a trial-and-error approach was used to predict the maximum allowable fuel pin temperature that satisfies the design criteria for steady-state normal operation. The steady-state temperature limits were used as the basis of the off-normal transient analysis to assess the safety performance of the fuel for anticipated, unlikely and extremely unlikely events. If the design criteria for the off-normal events are not satisfied, then the subassembly temperature limit is reduced and an iterative procedure is employed until all design criteria are met

Temperature biofeedback and sleep: limited findings and methodological challenges

Directory of Open Access Journals (Sweden)

De Koninck J

2012-10-01

Full Text Available Geneviève Forest,1,2 Cameron van den Heuvel,3 Kurt Lushington,4 Joseph De Koninck21Sleep Laboratory, Département de Psychoéducation et de Psychologie, Université du Québec en Outaouais, Gatineau, Québec, Canada; 2Sleep and Dreams Laboratory, School of Psychology, University of Ottawa, Ottawa, Ontario, Canada; 3Research Branch University of Adelaide, South Australia, Australia; 4School of Psychology, Social Work and Social Policy, University of South Australia, South Australia, AustraliaAbstract: Given the close link between body temperature and sleep, the perspective of manipulating core and peripheral temperature by self-regulation techniques is very appealing. We report here on a series of attempts conducted independently in two laboratories to use self-regulation (biofeedback of oral (central and hand (peripheral temperature, and measured the impact on sleep-onset latency, sleep architecture, and circadian phase. We found that hand temperature was more successful than oral temperature biofeedback. Moreover, an increase in hand temperature was associated with reduced sleep-onset latency. However, most participants found the procedure difficult to implement. The temperature response to biofeedback was reduced in the aged and weakest at the time of sleep onset, and there was not a systematic relationship between the change in temperature and change in sleep latency. Methodological limitations and individual differences may account for these results. Recommendations for future research are presented.Keywords: biofeedback, core body temperature, sleep, circadian rhythm, sleep onset

On the soft limit of the large scale structure power spectrum. UV dependence

International Nuclear Information System (INIS)

Garny, Mathias

2015-08-01

We derive a non-perturbative equation for the large scale structure power spectrum of long-wavelength modes. Thereby, we use an operator product expansion together with relations between the three-point function and power spectrum in the soft limit. The resulting equation encodes the coupling to ultraviolet (UV) modes in two time-dependent coefficients, which may be obtained from response functions to (anisotropic) parameters, such as spatial curvature, in a modified cosmology. We argue that both depend weakly on fluctuations deep in the UV. As a byproduct, this implies that the renormalized leading order coefficient(s) in the effective field theory (EFT) of large scale structures receive most of their contribution from modes close to the non-linear scale. Consequently, the UV dependence found in explicit computations within standard perturbation theory stems mostly from counter-term(s). We confront a simplified version of our non-perturbative equation against existent numerical simulations, and find good agreement within the expected uncertainties. Our approach can in principle be used to precisely infer the relevance of the leading order EFT coefficient(s) using small volume simulations in an 'anisotropic separate universe' framework. Our results suggest that the importance of these coefficient(s) is a ∝ 10% effect, and plausibly smaller.

Limitations to depth resolution in high-energy, heavy-ion elastic recoil detection analysis

International Nuclear Information System (INIS)

Elliman, R.G.; Palmer, G.R.; Ophel, T.R.; Timmers, H.

1998-01-01

The depth resolution of heavy-ion elastic recoil detection analysis was examined for Al and Co thin films ranging in thickness from 100 to 400 nm. Measurements were performed with 154 MeV Au ions as the incident beam, and recoils were detected using a gas ionisation detector. Energy spectra were extracted for the Al and Co recoils and the depth resolution determined as a function of film thickness from the width of the high- and low- energy edges. These results were compared with theoretical estimates calculated using the computer program DEPTH. (authors)

Resistive current limiter with high-temperature superconductors. Final report

International Nuclear Information System (INIS)

Schubert, M.

1995-12-01

Fundamental results of the possibility of using high temperature superconductors (HTSC) in resistive fault current limiters are discussed. Measurement of the homogeneity of BSCCO-powder-in-tube materials were made. In addition, investigations of the transition from superconducting to normalconducting state under AC-current conditions were carried out. Based on these results, simulations of HTSC-materials on ceramic substrate were made and recent results are presented. Important results of the investigations are: 1. Current-limiting without external trigger only possible when the critical current density of HTSC exceeds 10 4 A/cm 2 . 2. Inhomogeneities sometimes cause problems with local destruction. This can be solved by parallel-elements or external trigger. 3. Fast current-limiting causes overvoltages which can be reduced by using parallel-elements. (orig.) [de

Upper limits to trace constituents in Jupiter's atmosphere from an analysis of its 5 micrometer spectrum

Science.gov (United States)

Treffers, R. R.; Larson, H. P.; Fink, U.; Gautier, T. N.

1978-01-01

A high-resolution spectrum of Jupiter at 5 micrometers recorded at the Kuiper Airborne Observatory is used to determine upper limits to the column density of 19 molecules. The upper limits to the mixing ratios of SiH4, H2S, HCN, and simple hydrocarbons are discussed with respect to current models of Jupiter's atmosphere. These upper limits are compared to expectations based upon the solar abundance of the elements. This analysis permits upper limit measurements (SiH4), or actual detections (GeH4) of molecules with mixing ratios with hydrogen as low as 10 to the minus 9th power. In future observations at 5 micrometers the sensitivity of remote spectroscopic analyses should permit the study of constituents with mixing ratios as low as 10 to the minus 10th power, which would include the hydrides of such elements as Sn and As as well as numerous organic molecules.

A measurement of the low frequency spectrum of the cosmic microwave background radiation

International Nuclear Information System (INIS)

Levin, S.M.

1987-04-01

As part of a larger effort to measure the spectrum of the Cosmic Background Radiation (CBR) at low frequencies, the intensity of the CBR has been measured at a frequency of 1.410 GHz. The measurement was made by comparing the power received from the sky with the power received from a specially designed cooled calibration target with known properties. Sources of radiation other than the CBR were then identified and subtracted to calculate the antenna temperature of the CBR at 1.410 GHz. The instrument used to measure the CBR was a total-power microwave radiometer with a 25 MHz bandwidth centered at 1.410 GHz. The radiometer had a noise temperature of 80 K, and sufficient data were taken that radiometer noise did not contribute significantly to the total measurement error. The sources of error were predominantly systematic in nature, and the largest error was due to uncertainty in the reflection characteristics of the cold-load calibrator. Identification and subtraction of signals from the Galaxy (0.7 K) and the Earth's atmosphere (0.8 K) were also significant parts of the data reduction and error analysis. The brightness temperature of the Cosmic Background Radiation at 1.410 GHz is 222. +- 0.55 Kelvin. The spectrum of the CBR, as determined by this measurement and other published results, is consistent with a blackbody spectrum of temperature 2.741 +- 0.016. Constraints on the amount by which the CBR spectrum deviates from Planck spectrum are used to place limits on energy releases early in the history of the universe. 55 refs., 25 figs., 8 tabs

Influence of temperature, precipitation, and cultivar characteristics on changes in the spectrum of pathogenic fungi in winter wheat.

Science.gov (United States)

Hýsek, Josef; Vavera, Radek; Růžek, Pavel

2017-06-01

In view of the threat posed by climate change, we studied the influence of temperature, precipitation, cultivar characteristics, and technical management measures on the occurrence of phytopathogenic fungi in wheat during 2009-2013. This work involved experiments at two sites differing in average temperatures and precipitation. Temperature and precipitation appear to influence differences in the spectrum of phytopathogenic fungi at the individual sites. In 2009 (the warmest year), Alternaria triticina was dominant. In 2010 (having the smallest deviations from the average for individual years), Septoria tritici dominated. In 2011, Puccinia triticina was most prominent, while in 2012, the genus Drechslera (Pyrenophora) and in 2013, S. tritici and Drechslera tritici-repentis (DTR) dominated. Temperature and precipitation levels in the individual spring months (warmer March to May) played a large role, especially for the leaf rust P. triticina in 2011. A change of only 1 °C with different precipitation during a year played a significant role in changing wheat's fungal spectrum. Cluster analysis showed the differences between single pathogenic fungi on wheat in a single year due to temperature and precipitation. Alternaria abundance was strongly influenced by year (p < 0.001) while locality was significant only in certain years (2012, 2013; p = 0.004 and 0.015, respectively). The same factors were revealed to be significant in the case of Puccinia, but locality played a role (p < 0.001) in different years (2011, 2013). The abundance of S. tritici and Pyrenophora tritici-repentis (Drechslera tritici-repentis) was influenced only by year (p < 0.001).

A portable borehole temperature logging system using the four-wire resistance method

Science.gov (United States)

Erkan, Kamil; Akkoyunlu, Bülent; Balkan, Elif; Tayanç, Mete

2017-12-01

High-quality temperature-depth information from boreholes with a depth of 100 m or more is used in geothermal studies and in studies of climate change. Electrical wireline tools with thermistor sensors are capable of measuring borehole temperatures with millikelvin resolution. The use of a surface readout mode allows analysis of the thermally conductive state of a borehole, which is especially important for climatic and regional heat flow studies. In this study we describe the design of a portable temperature logging tool that uses the four-wire resistance measurement method. The four-wire method enables the elimination of cable resistance effects, thus allowing millikelvin resolution of temperature data at depth. A preliminary two-wire model of the system is also described. The portability of the tool enables one to collect data from boreholes down to 300 m, even in locations with limited accessibility.

Depth, chemical, and temperature from bottle casts in the Sea of Okhotsk from 29 June 1990 to 31 August 1997 (NODC Accession 0000385)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Depth, chemical, and temperature data were collected from the SAMOED, AKADEMIK ALEKSANDR NESMEYANOV, AKADEMIK M.A. LAVRENTYEV, and PROFESSOR LEVANIDOV from June 29,...

The JET belt limiter tiles

International Nuclear Information System (INIS)

Deksnis, E.

1988-09-01

The belt limiter system, comprising two full toroidal rings of limiter tiles, was installed in JET in 1987. In consists of water-cooled fins with the limiter material in form of tile inbetween. The tiles are designed to absorb heat fluxes during irradiation without the surface temperature exceeding 2000 0 C and to radiate this heat between pulses to the water cooled sink whose temperature is lower than that of the vacuum vessel. An important feature of the design is to maximise the area of the radiating surface facing the water cooled fin. This leads to a tile depth much greater than the width of the tile facing the heat flux. Limiter tiles intercept particles flowing out of the plasma through the area between the two belt limiter rings and through remaining surface area of the plasma column. Power deposition to a limiter tile depends strongly on the shape of the plasma, the edge plasma properties as well as on the surface profile of the tiles. This paper will discuss the methodology that was followed in producing an optimized surface profile of the tiles. This shaped profile has the feature that the resulting power deposition profile is roughly similar for a wide range of plasma parameters. (author)

Stability of eelgrass (Zostera marina L.) depth limits: influence of habitat type

DEFF Research Database (Denmark)

Greve, T. M.; Krause-Jensen, D.

2005-01-01

significantly between habitat types, and neither did stability of physicochemical variables. However, when data from all habitat types were analysed together, they showed that eelgrass populations at the depth limit were significantly more constant and thus, in this respect, more stable when occurring in deep......Seagrass meadows are generally considered stable although few studies have specified and tested this statement. On the basis of a large monitoring dataset from Danish coastal waters, we aimed to test whether the stability of deep eelgrass populations changes along a eutrophication gradient...... waters as compared to shallow waters. Areas of good water quality may thus obtain the double benefit of deeper-growing and more stable eelgrass populations. The most likely reason why this pattern did not appear at habitat-type level is that the habitat types studied represented wide spatial variation...

The Hengill geothermal area, Iceland: variation of temperature gradients deduced from the maximum depth of seismogenesis

Science.gov (United States)

Foulger, G.R.

1995-01-01

Given a uniform lithology and strain rate and a full seismic data set, the maximum depth of earthquakes may be viewed to a first order as an isotherm. These conditions are approached at the Hengill geothermal area, S. Iceland, a dominantly basaltic area. The temperature at which seismic failure ceases for the strain rates likely at the Hengill geothermal area is determined by analogy with oceanic crust, and is about 650 ?? 50??C. The topographies of the top and bottom of the seismogenic layer were mapped using 617 earthquakes. The thickness of the seismogenic layer is roughly constant and about 3 km. A shallow, aseismic, low-velocity volume within the spreading plate boundary that crosses the area occurs above the top of the seismogenic layer and is interpreted as an isolated body of partial melt. The base of the seismogenic layer has a maximum depth of about 6.5 km beneath the spreading axis and deepens to about 7 km beneath a transform zone in the south of the area. -from Author

Wet-bulb globe temperature (WBGT)--its history and its limitations.

Science.gov (United States)

Budd, Grahame M

2008-01-01

Wet-bulb globe temperature (WBGT) is nowadays the most widely used index of heat stress, yet many users appear to be unaware of its history and its limitations. HISTORY OF WBGT: WBGT was invented and first used during the 1950s as one element in a successful campaign to control serious outbreaks of heat illness in training camps of the United States Army and Marine Corps. Control measures based on air temperature and humidity, and applied to all trainees alike, had proved effective but had entailed excessive compliance costs in the form of lost training time. New control measures introduced in 1956 further reduced heat illness and also lost fewer training hours. Crucial innovations were (1) replacing the temperature and humidity measurements with WBGT, which additionally responds to sun and wind, (2) using epidemiologic analyses of casualty records to identify hazardous levels of WBGT and vulnerable trainees, and (3) protecting the most vulnerable trainees by suspending drill at lower levels of WBGT, and by improving their heat tolerance in special conditioning platoons. This campaign has considerable relevance to the prevention of heat illness in sport. LIMITATIONS OF WBGT: WBGT's most serious limitation is that environments at a given level of the index are more stressful when the evaporation of sweat is restricted (by high humidity or low air movement) than when evaporation is free. As with all indices that integrate elements of the thermal environment, interpretation of the observed levels of WBGT requires careful evaluation of people's activity, clothing, and many other factors, all of which can introduce large errors into any predictions of adverse effects. Moreover, the accuracy of WBGT is being eroded by measurement errors associated with the omission of the globe temperature, with non-standard instrumentation, and with unsatisfactory calibration procedures. Because of the above limitations WBGT can provide only a general guide to the likelihood of adverse

Lower limit on the achievable temperature in resonator-based sideband cooling

Science.gov (United States)

Grajcar, M.; Ashhab, S.; Johansson, J. R.; Nori, F.

2009-03-01

A resonator with eigenfrequency φr can be effectively used as a cooler for another linear oscillator with a much smaller frequency φmφr. A huge cooling effect, which could be used to cool a mechanical oscillator below the energy of quantum fluctuations, has been predicted by several authors. However, here we show that there is a lower limit T^* on the achievable temperature, given by T^* = Tm; φm/ φr, that was not considered in previous work and can be higher than the quantum limit in realistic experimental realizations. We also point out that the decay rate of the resonator, which previous studies stress should be small, must be larger than the decay rate of the cooled oscillator for effective cooling. M. Grajcar, S. Ashhab, J.R. Johansson, F. Nori, Lower limit on the achievable temperature in resonator-based sideband cooling, Phys. Rev. B 78, 035406 (2008). URL: http://link.aps.org/abstract/PRB/v78/e035406

Temperature limit values for touching cold surfaces with the fingertip

NARCIS (Netherlands)

Geng, Q.; Holme, I.; Hartog, E.A. den; Havenith, G.; Jay, O.; Malchaires, J.; Piette, A.; Rintama, H.; Rissanen, S.

2006-01-01

Objectives: At the request of the European Commission and in the framework of the European Machinery Directive, research was performed in five different laboratories to develop specifications for surface temperature limit values for the short-term accidental touching of the fingertip with cold

On the zero temperature limit of the Kubo-transformed quantum time correlation function

Science.gov (United States)

Hernández de la Peña, Lisandro

2014-04-01

The zero temperature limit of several quantum time correlation functions is analysed. It is shown that while the canonical quantum time correlation function retains the full dynamical information as temperature approaches zero, the Kubo-transformed and the thermally symmetrised quantum time correlation functions lose all dynamical information at this limit. This is shown to be a consequence of the projection onto the ground state, via the limiting process of the quantities ? and ?, either together as a product, or separately. Although these findings would seem to suggest that finite-temperature methods commonly used to estimate Kubo correlation functions would be incapable of retaining any ground state dynamics, we propose a route for recovering in principle all dynamical information at the ground state. It is first shown that the usual frequency space relation between canonical and Kubo correlation functions also holds for microcanonical time correlation functions. Since the Kubo-transformed microcanonical correlation function can be obtained from the usual finite-temperature function by including a projection onto the corresponding microcanonical ensemble, finite-temperature methods, properly modified to incorporate such a constraint, can be used to capture full quantum dynamics at any arbitrary energy state, including the ground state. This approach is illustrated with the application of centroid dynamics to the ground state dynamics of the harmonic oscillator.

Multiple and double scattering contributions to depth resolution and low energy background in hydrogen elastic recoil detection

Energy Technology Data Exchange (ETDEWEB)

Wielunski, L.S. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics

1996-12-31

The sensitivity of hydrogen elastic recoil detection ( ERD ) is usually limited by the low energy background in the ERD spectrum. A number of 4.5 MeV He{sup ++} hydrogen ERD spectra from different hydrogen implanted samples are compared. The samples are chosen with different atomic numbers from low Z (carbon) to high Z (tungsten carbide) to observe the effects of multiple scattering and double scattering within the sample material. The experimental depth resolution and levels of the low energy background in ERD spectra are compared with theoretical predictions from multiple and double scattering. 10 refs., 2 tabs., 5 figs.

Multiple and double scattering contributions to depth resolution and low energy background in hydrogen elastic recoil detection

Energy Technology Data Exchange (ETDEWEB)

Wielunski, L S [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics

1997-12-31

The sensitivity of hydrogen elastic recoil detection ( ERD ) is usually limited by the low energy background in the ERD spectrum. A number of 4.5 MeV He{sup ++} hydrogen ERD spectra from different hydrogen implanted samples are compared. The samples are chosen with different atomic numbers from low Z (carbon) to high Z (tungsten carbide) to observe the effects of multiple scattering and double scattering within the sample material. The experimental depth resolution and levels of the low energy background in ERD spectra are compared with theoretical predictions from multiple and double scattering. 10 refs., 2 tabs., 5 figs.

Why bother about depth?

DEFF Research Database (Denmark)

Stæhr, Peter A.; Obrador, Biel; Christensen, Jesper Philip

We present results from a newly developed method to determine depth specific rates of GPP, NEP and R using frequent automated profiles of DO and temperature. Metabolic rate calculations were made for three lakes of different trophic status using a diel DO methodology that integrates rates across...

Indoor measurement of photovoltaic device characteristics at varying irradiance, temperature and spectrum for energy rating

International Nuclear Information System (INIS)

Bliss, M; Betts, T R; Gottschalg, R

2010-01-01

The first three-dimensional performance matrix for use in photovoltaic (PV) energy rating is reported utilizing a novel energy rating solar simulator based on LEDs. Device characteristics are measured indoors at varying irradiance (G), temperature (T) and spectrum (E). This opens the possibility for a more accurate measurement system for energy yield prediction of PV devices, especially for devices with high spectral dependence such as wide bandgap solar cells as they take into account spectral changes in the light. The main aspects of the LED-based solar simulator used are briefly described. A measurement method is developed and detailed in the paper, which takes into account the current imperfections in the achievable spectrum. Measurement results for a crystalline silicon solar cell are used to demonstrate the measurement approach. An uncertainty analysis of the measurement system is given, resulting in an overall absolute uncertainty of 4.3% (coverage factor k = 2) in maximum power measurements at 765 W m −2 irradiance with scope for further improvements

Detection of a surface breaking crack by using the centroid variations of laser ultrasonic spectrums

International Nuclear Information System (INIS)

Park, Seung Kyu; Baik, Sung Hoon; Lim, Chang Hwan; Joo, Young Sang; Jung, Hyun Kyu; Cha, Hyung Ki; Kang, Young June

2006-01-01

A laser ultrasonic system is a non-contact inspection device with a wide-band spectrum and a high spatial resolution. It provides absolute measurements of the moving distance and it can be applied to hard-to-access locations including curved or rough surfaces like in a nuclear power plant. In this paper, we have investigated the detection methods of the depth of a surface-breaking crack by using the surface wave of a laser ultrasound. The filtering function of a surface-breaking crack is a kind of a low-pass filter. The higher frequency components are more highly decreased in proportion to the crack depth. Also, the center frequency value of each ultrasound spectrum is decreased in proportion to the crack depth. We extracted the depth information of a surface-breaking crack by observing the centroid variation of the frequency spectrum. We describe the experimental results to detect the crack depth information by using the peak-to-valley values in the time domain and the center frequency values in the frequency domain.

Measurement and modeling of the low-temperature penetration-depth anomaly in high-quality MgB{sub 2} thin films

Energy Technology Data Exchange (ETDEWEB)

Agassi, Y.D. [Naval Surface Warfare Center, Carderock Division, Bethesda, MD 20817 (United States); Oates, D.E., E-mail: OATES@LL.MIT.EDU [MIT-Lincoln Laboratory, Lexington, MA 02420 (United States); Moeckly, B.H. [STI, Inc. Santa Barbara, CA 93111 (United States)

2012-10-15

Based on our measurements of intermodulation distortion in MgB{sub 2}, we have previously proposed that the {pi} energy-gap in MgB{sub 2} entails six nodal lines [Y.D. Agassi, D.E. Oates, and B.H. Moeckly, Phys. Rev. B 80 (2009) 174522]. Here we report high-precision measurements in MgB{sub 2} stripline resonators that show an increase of the penetration depth as the temperature is decreased below 5 K. This increase is consistent with the Script-Small-L = 6 symmetry of the {pi} energy gap that we have proposed. We interpret the increase as a manifestation of Andreev surface-attached states that are associated with the nodal lines of the {pi} energy gap. Penetration-depth calculations are in good agreement with our data. To reconcile the present interpretation with existing literature, we review other penetration-depth data, magnetic-impurity and tunneling experiments, and data on the paramagnetic Meissner effect. We conclude that these data do not rule out the interpretation of our experimental data based on a nodal {pi} energy gap.

Wilson Loops in the Large N Limit at Finite Temperature

OpenAIRE

Brandhuber, A.; Itzhaki, N.; Sonnenschein, J.; Yankielowicz, S.

1998-01-01

Using a proposal of Maldacena we compute in the framework of the supergravity description of N coincident D3 branes the energy of a quark anti-quark pair in the large N limit of U(N) N=4 SYM in four dimensions at finite temperature.

Resource management for energy and spectrum harvesting sensor networks

CERN Document Server

Zhang, Deyu; Zhou, Haibo; Shen, Xuemin (Sherman)

2017-01-01

This SpringerBrief offers a comprehensive review and in-depth discussion of the current research on resource management. The authors explain how to best utilize harvested energy and temporally available licensed spectrum. Throughout the brief, the primary focus is energy and spectrum harvesting sensor networks (ESHNs) including energy harvesting (EH)-powered spectrum sensing and dynamic spectrum access. To efficiently collect data through the available licensed spectrum, this brief examines the joint management of energy and spectrum. An EH-powered spectrum sensing and management scheme for Heterogeneous Spectrum Harvesting Sensor Networks (HSHSNs) is presented in this brief. The scheme dynamically schedules the data sensing and spectrum access of sensors in ESHSNs to optimize the network utility, while considering the stochastic nature of EH process, PU activities and channel conditions. This brief also provides useful insights for the practical resource management scheme design for ESHSNs and motivates a ne...

Moisture rivals temperature in limiting photosynthesis by trees establishing beyond their cold-edge range limit under ambient and warmed conditions.

Science.gov (United States)

Moyes, Andrew B; Germino, Matthew J; Kueppers, Lara M

2015-09-01

Climate change is altering plant species distributions globally, and warming is expected to promote uphill shifts in mountain trees. However, at many cold-edge range limits, such as alpine treelines in the western United States, tree establishment may be colimited by low temperature and low moisture, making recruitment patterns with warming difficult to predict. We measured response functions linking carbon (C) assimilation and temperature- and moisture-related microclimatic factors for limber pine (Pinus flexilis) seedlings growing in a heating × watering experiment within and above the alpine treeline. We then extrapolated these response functions using observed microclimate conditions to estimate the net effects of warming and associated soil drying on C assimilation across an entire growing season. Moisture and temperature limitations were each estimated to reduce potential growing season C gain from a theoretical upper limit by 15-30% (c. 50% combined). Warming above current treeline conditions provided relatively little benefit to modeled net assimilation, whereas assimilation was sensitive to either wetter or drier conditions. Summer precipitation may be at least as important as temperature in constraining C gain by establishing subalpine trees at and above current alpine treelines as seasonally dry subalpine and alpine ecosystems continue to warm. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

The Influence of Tuners and Temperature on the Higher Order Mode Spectrum for 1.3 GHz SCRF Cavities

CERN Document Server

Ainsworth, R; Zhang, P; Grecki, M; Baboi, N; Wamsat, T; Eddy, N

2013-01-01

Higher Order Modes (HOMs) are of concern for superconducting cavities as they can drive instabilities and so are usually damped and monitored. With special dedicated electronics, HOMs can provide information on the position on the beam. It has been proposed that piezo tuners used to keep the cavities operating at 1.3 GHz could alter the HOM spectrum altering the calibration constants used to read out the beam position affecting long term stability of the system. Also, of interest is how the cavity reacts to the slow tuner. Detuning and the retuning the cavity may alter the HOM spectrum. This is of particular interest for future machines not planning to use dedicated HOM damping as the tuning procedure may shift the frequency of HOMs onto dangerous resonances. The effect of temperature on the HOM spectrum is also investigated. An investigation of these effects has been performed at FLASH and the results are presented.

DEPTH - OBSERVATION and Other Data (NODC Accession 9700138)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature, salinity and other data were collected in the North Sea and other locations. Data include water depths, temperatures, salinities, and oxygen...

Accurate Depth of Radiofrequency-Induced Lesions in Renal Sympathetic Denervation Based on a Fine Histological Sectioning Approach in a Porcine Model.

Science.gov (United States)

Sakaoka, Atsushi; Terao, Hisako; Nakamura, Shintaro; Hagiwara, Hitomi; Furukawa, Toshihito; Matsumura, Kiyoshi; Sakakura, Kenichi

2018-02-01

Ablation lesion depth caused by radiofrequency-based renal denervation (RDN) was limited to radiofrequency-RDN cannot ablate a substantial percentage of renal sympathetic nerves. We aimed to define the true lesion depth achieved with radiofrequency-RDN using a fine sectioning method and to investigate biophysical parameters that could predict lesion depth. Radiofrequency was delivered to 87 sites in 14 renal arteries from 9 farm pigs at various ablation settings: 2, 4, 6, and 9 W for 60 seconds and 6 W for 120 seconds. Electric impedance and electrode temperature were recorded during ablation. At 7 days, 2470 histological sections were obtained from the treated arteries. Maximum lesion depth increased at 2 to 6 W, peaking at 6.53 (95% confidence interval, 4.27-8.78) mm under the 6 W/60 s condition. It was not augmented by greater power (9 W) or longer duration (120 seconds). There were statistically significant tendencies at 6 and 9 W, with higher injury scores in the media, nerves, arterioles, and fat. Maximum lesion depth was positively correlated with impedance reduction and peak electrode temperature (Pearson correlation coefficients were 0.59 and 0.53, respectively). Lesion depth was 6.5 mm for radiofrequency-RDN at 6 W/60 s. The impedance reduction and peak electrode temperature during ablation were closely associated with lesion depth. Hence, these biophysical parameters could provide prompt feedback during radiofrequency-RDN procedures in the clinical setting. © 2018 The Authors.

Microbial habitat connectivity across spatial scales and hydrothermal temperature gradients at Guaymas Basin

Directory of Open Access Journals (Sweden)

Stefanie eMeyer

2013-07-01

Full Text Available The Guaymas Basin (Gulf of California hydrothermal vent area is known as a dynamic and hydrothermally vented sedimentary system, where the advection and production of a variety of different metabolic substrates support a high microbial diversity and activity in the seafloor. The main objective of our study was to explore the role of temperature and other environmental factors on community diversity, such as the presence of microbial mats and seafloor bathymetry within one hydrothermally vented field of 200 × 250 m dimension. In this field, temperature increased strongly with sediment depth reaching the known limit to life within a few decimeters. Potential sulfate reduction rate as a key community activity parameter was strongly affected by in situ temperature and sediment depth, declining from high rates of 1-5 μmol ml-1 d-1 at the surface to the detection limit below 5 cm sediment depth, despite the presence of sulfate and hydrocarbons. Automated Ribosomal Intergenic Spacer Analysis yielded a high-resolution fingerprint of the dominant members of the bacterial community. Our analyses showed strong temperature and sediment depth effects on bacterial cell abundance and Operational Taxonomic Units (OTUs number, both declining by more than one order of magnitude below the top 5 cm of the sediment surface. Another fraction of the variation in diversity and community structure was explained by differences in the local bathymetry and spatial position within the vent field. Nevertheless, more than 80% of all detected OTUs were shared among the different temperature realms and sediment depths, after being classified as cold (T<10°C, medium (10°C≤T<40°C or hot (T≥40°C temperature conditions, with significant OTU overlap with the richer surface communities. Overall, this indicates a high connectivity of benthic bacterial habitats in this dynamic and heterogeneous marine ecosystem influenced by strong hydrothermalism.

Confirmation of a change in the global shear velocity pattern at around 1000 km depth

Science.gov (United States)

Durand, S.; Debayle, E.; Ricard, Y.; Zaroli, C.; Lambotte, S.

2017-12-01

In this study, we confirm the existence of a change in the shear velocity spectrum around 1000 km depth based on a new shear velocity tomographic model of the Earth's mantle, SEISGLOB2. This model is based on Rayleigh surface wave phase velocities, self- and cross-coupling structure coefficients of spheroidal normal modes and body wave traveltimes which are, for the first time, combined in a tomographic inversion. SEISGLOB2 is developed up to spherical harmonic degree 40 and in 21 radial spline functions. The spectrum of SEISGLOB2 is the flattest (i.e. richest in 'short' wavelengths corresponding to spherical harmonic degrees greater than 10) around 1000 km depth and this flattening occurs between 670 and 1500 km depth. We also confirm various changes in the continuity of slabs and mantle plumes all around 1000 km depth where we also observed the upper boundary of Large Low Shear Velocity Provinces. The existence of a flatter spectrum, richer in short-wavelength heterogeneities, in a region of the mid-mantle can have great impacts on our understanding of the mantle dynamics and should thus be better understood in the future. Although a viscosity increase, a phase change or a compositional change can all concur to induce this change of pattern, its precise origin is still very uncertain.

Design and construction of an analytical instrument for neutron depth profiling

International Nuclear Information System (INIS)

Mutis, Octavio; Venegas, Rafael

1998-01-01

Full text: An experimental facility for Neutron Depth Profiling, recently constructed at CCHEN's laboratories is described. The technique allows to measure the mean atomic concentration ρ(x) of certain isotopes as a function of distance x to the surface for the first depth microns. The observation area is about 15 mm in diameter and the range in depth depends on the matrix stopping power and on the energy of the charged particle associated with the A(n,y)B reaction, in which this technique is supported, where A is the isotope to be detected, y is an α particle or a proton and B is the recoil nucleus. The spatial resolution depends upon the characteristics of the detection chain and its geometry and of the thermal spectrum of the beam. An appropriate deconvolution on the merging particle energy spectrum allows to recover the concentration profile. The application of the technique to the analysis of some phospho borosilicate films deposited on s Si substrate, lithium tantalate ceramics deposited on Si substrate and a sintered of lithium and Zn-Ni-Mn oxide are shown here with a resolution comparative to that of advanced laboratories

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across Wake Island from 2014-03-16 to 2014-03-19 (NCEI Accession 0162248)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across Jarvis Island from 2016-05-19 to 2016-05-23 (NCEI Accession 0162245)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across American Samoa from 2015-02-15 to 2015-03-28 (NCEI Accession 0161169)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

Nonlinear evolution of f(R) cosmologies. II. Power spectrum

International Nuclear Information System (INIS)

Oyaizu, Hiroaki; Hu, Wayne; Lima, Marcos

2008-01-01

We carry out a suite of cosmological simulations of modified action f(R) models where cosmic acceleration arises from an alteration of gravity instead of dark energy. These models introduce an extra scalar degree of freedom which enhances the force of gravity below the inverse mass or Compton scale of the scalar. The simulations exhibit the so-called chameleon mechanism, necessary for satisfying local constraints on gravity, where this scale depends on environment, in particular, the depth of the local gravitational potential. We find that the chameleon mechanism can substantially suppress the enhancement of power spectrum in the nonlinear regime if the background field value is comparable to or smaller than the depth of the gravitational potentials of typical structures. Nonetheless power spectrum enhancements at intermediate scales remain at a measurable level for models even when the expansion history is indistinguishable from a cosmological constant, cold dark matter model. Simple scaling relations that take the linear power spectrum into a nonlinear spectrum fail to capture the modifications of f(R) due to the change in collapsed structures, the chameleon mechanism, and the time evolution of the modifications.

Clinical Ethics in Gabon: The Spectrum of Clinical Ethical Issues Based on Findings from In-Depth Interviews at Three Public Hospitals.

Science.gov (United States)

Sippel, Daniel; Marckmann, Georg; Ndzie Atangana, Etienne; Strech, Daniel

2015-01-01

Unlike issues in biomedical research ethics, ethical challenges arising in daily clinical care in Sub-Saharan African countries have not yet been studied in a systematic manner. However this has to be seen as a distinct entity as we argue in this paper. Our aim was to give an overview of the spectrum of clinical ethical issues and to understand what influences clinical ethics in the Sub-Saharan country of Gabon. In-depth interviews with 18 health care professionals were conducted at three hospital sites in Gabon. Interview transcripts were analyzed using a grounded theory approach (open and axial coding), giving a qualitative spectrum of categories for clinical ethical issues. Validity was checked at a meeting with study participants and other health care experts in Gabon after analysis of the data. Twelve main categories (with 28 further-specified subcategories) for clinical ethical issues were identified and grouped under three core categories: A) micro level: "confidentiality and information", "interpersonal, relational and behavioral issues", "psychological strain of individuals", and "scarce resources"; B) meso level: "structural issues of medical institutions", "issues with private clinics", "challenges connected to the family", and "issues of education, training and competence"; and C) macro level: "influence of society, culture, religion and superstition", "applicability of western medicine", "structural issues on the political level", and "legal issues". Interviewees reported a broad spectrum of clinical ethical issues that go beyond challenges related to scarce financial and human resources. Specific socio-cultural, historical and educational backgrounds also played an important role. In fact these influences are central to an understanding of clinical ethics in the studied local context. Further research in the region is necessary to put our study into perspective. As many participants reported a lack of awareness of ethical issues amongst other health

Time and spectrum-resolving multiphoton correlator for 300–900 nm

Energy Technology Data Exchange (ETDEWEB)

Johnsen, Kelsey D.; Thibault, Marilyne; Jennewein, Thomas [Institute for Quantum Computing and Department for Physics and Astronomy, University of Waterloo, 200 University Ave. West, Waterloo, Ontario N2L 3G1 (Canada); Kolenderski, Piotr, E-mail: kolenderski@fizyka.umk.pl [Institute for Quantum Computing and Department for Physics and Astronomy, University of Waterloo, 200 University Ave. West, Waterloo, Ontario N2L 3G1 (Canada); Faculty of Physics, Astronomy and Informatics, Institute of Physics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland); Scarcella, Carmelo; Tosi, Alberto [Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 Milano (Italy)

2014-10-14

We demonstrate a single-photon sensitive spectrometer in the visible range, which allows us to perform time-resolved and multi-photon spectral correlation measurements at room temperature. It is based on a monochromator composed of two gratings, collimation optics, and an array of single photon avalanche diodes. The time resolution can reach 110 ps and the spectral resolution is 2 nm/pixel, limited by the design of the monochromator. This technique can easily be combined with commercial monochromators and can be useful for joint spectrum measurements of two photons emitted in the process of parametric down conversion, as well as time-resolved spectrum measurements in optical coherence tomography or medical physics applications.

Chlorophyll, temperature, depth, and irradiance data from bottle in a world-wide distribution from 28 February 1964 to 02 April 1994 (NODC Accession 0000268)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Chlorophyll, temperature, depth, and irradiance data were collected using bottle from multiple vessels in a world-wide distribution from 28 February 1964 to 02 April...

Depth of magnetic basement in Iran based on fractal spectral analysis of aeromagnetic data

Science.gov (United States)

Teknik, Vahid; Ghods, Abdolreza

2017-06-01

To estimate the shape of sedimentary basins, a critical parameter in hydrocarbon exploration, we calculated the depth of magnetic basement by applying a fractal spectral method to the aeromagnetic map of Iran. The depth of magnetic basement is a close proxy for the shape of sedimentary basins provided that igneous basement is strongly magnetized relative to the overlying sediments and there is no interbedding magnetic layer in the sediments. The shape of the power spectrum of magnetic anomalies is sensitive to the depth of magnetic basement, the thickness of the magnetic layer, the fractal parameter of magnetization and the size of the window used for the calculation of the power spectrum. Using a suite of synthetic tests, we have shown that the estimation of the depth of magnetic basement of up to 20 km is not very sensitive to the often unknown fractal parameter and thus the spectral method is a reliable tool to calculate the depth of magnetic basement. The depth of magnetic basement is in the range of 7-16 km in the Zagros, east Alborz, Tabas, Jazmurian and Makran regions, showing a close correlation with depths estimated from the maximum thickness of stratigraphic columns. We have also found new sedimentary basins in Bostan Abad, Bijar and south of Orumiyeh Lake. The significant depth of the magnetic basement in the Makran, Jazmurain depression, southeast Caspian Sea, Tabas, Great Kavir, south of Orumiyeh Lake, Bostan Abad and Bijar sedimentary basins makes them future prospects for hydrocarbon explorations. The depth of magnetic basement is strongly reduced over the Neyriz and Kermanshah Ophiolites, but it does not show any meaningful correlation with other outcrops of ophiolitic rocks in Iran.

New method of interpretation of the solar spectrum lines

International Nuclear Information System (INIS)

Sitnik, G.F.

1975-01-01

Close triplet lines, which appear from a common low level or from low sublevels with small energy difference are used. It is supposed that for such lines both the function of the source in line and the frequency dependence of the selective coefficient of absorption are the same over any depth of the region of line production in the atmosphere and change with the depth equally. The residual intensities of some lines of the triplet, which are measured for every line at a number of profile points (at the same distance from its center and at different distances from the solar limb center), serve as initial material. The intensities are expressed in terms of the intensity of the continuous spectrum in the center of the solar limb for the average wave length of the triplet interval. Such observations avoid the usual assumption about the source function constancy in line inside the line. On the contrary, the frequency dependence of this function is clarified by the use of this method. Calculations make it possible to determine the source function in line and its long-wave dependence inside the line; to derive a solar atmosphere model and to determine the source function in the continuous spectrum in accordance with observations at profile points in its middle part and in the wing; to find the relation between the selective and continuous absorption coefficients in the dependence on the optical depth in the continuous spectrum; and to find the long-wave dependences of coefficients for both the selective absorption and the selective emission at different optical depths

Estimation of the lower flammability limit of organic compounds as a function of temperature.

Science.gov (United States)

Rowley, J R; Rowley, R L; Wilding, W V

2011-02-15

A new method of estimating the lower flammability limit (LFL) of general organic compounds is presented. The LFL is predicted at 298 K for gases and the lower temperature limit for solids and liquids from structural contributions and the ideal gas heat of formation of the fuel. The average absolute deviation from more than 500 experimental data points is 10.7%. In a previous study, the widely used modified Burgess-Wheeler law was shown to underestimate the effect of temperature on the lower flammability limit when determined in a large-diameter vessel. An improved version of the modified Burgess-Wheeler law is presented that represents the temperature dependence of LFL data determined in large-diameter vessels more accurately. When the LFL is estimated at increased temperatures using a combination of this model and the proposed structural-contribution method, an average absolute deviation of 3.3% is returned when compared with 65 data points for 17 organic compounds determined in an ASHRAE-style apparatus. Copyright © 2010 Elsevier B.V. All rights reserved.

Local atomic structure of Fe/Cr multilayers: Depth-resolved method

Science.gov (United States)

Babanov, Yu. A.; Ponomarev, D. A.; Devyaterikov, D. I.; Salamatov, Yu. A.; Romashev, L. N.; Ustinov, V. V.; Vasin, V. V.; Ageev, A. L.

2017-10-01

A depth-resolved method for the investigation of the local atomic structure by combining data of X-ray reflectivity and angle-resolved EXAFS is proposed. The solution of the problem can be divided into three stages: 1) determination of the element concentration profile with the depth z from X-ray reflectivity data, 2) determination of the X-ray fluorescence emission spectrum of the element i absorption coefficient μia (z,E) as a function of depth and photon energy E using the angle-resolved EXAFS data Iif (E , ϑl) , 3) determination of partial correlation functions gij (z , r) as a function of depth from μi (z , E) . All stages of the proposed method are demonstrated on a model example of a multilayer nanoheterostructure Cr/Fe/Cr/Al2O3. Three partial pair correlation functions are obtained. A modified Levenberg-Marquardt algorithm and a regularization method are applied.

A novel method to hit the limit temperature of Stirling-type cryocooler

Science.gov (United States)

Wang, Jue; Pan, Changzhao; Zhang, Tong; Luo, Kaiqi; Zhou, Yuan; Wang, Junjie

2018-02-01

The Stirling-type cryocooler with its compact size and high efficiency is always expected to obtain its temperature limit of below 3 K. However, the pressure drop losses caused by high-frequency oscillation create large obstacles for this objective. This paper reports a novel thermal-driven Stirling-type cryocooler to obtain the lowest temperature of a Stirling-type cryocooler. The advantages of a thermal-driven cryocooler (Vuilleumier cryocooler) and pulse tube cryocooler are combined with a new type of cryocooler, called the Vuilleumier gas-coupling pulse tube hybrid cryocooler (VM-PT). A prototype of the VM-PT was recently developed and optimized in our laboratory. By using helium-4 as the working gas and magnetic regenerative materials (HoCu2 and Er3Ni), the lowest temperature of 2.5 K was obtained, which can be regarded as an important breakthrough for the Stirling-type cryocooler to achieve its limit temperature of below 3 K. It can supply >30 mW cooling power at 4.2 K and >500 mW cooling power at 20 K simultaneously. Theoretically, it is feasible to use this VM-PT for cooling the superconducting devices in space applications.

Generalized Grüneisen parameters and low temperature limit of ...

Indian Academy of Sciences (India)

The low temperature limit of volume thermal expansion calculated here for cad- mium and zirconium is found to be positive and so we expect a positive volume expansion down to 0 K even though the mode gammas are negative. The mea- surement of higher-order elastic constants and hence the calculation of the thermal.

In situ burning of oil in coastal marshes. 1. Vegetation recovery and soil temperature as a function of water depth, oil type, and marsh type.

Science.gov (United States)

Lin, Qianxin; Mendelssohn, Irving A; Bryner, Nelson P; Walton, William D

2005-03-15

In-situ burning of oiled wetlands potentially provides a cleanup technique that is generally consistent with present wetland management procedures. The effects of water depth (+10, +2, and -2 cm), oil type (crude and diesel), and oil penetration of sediment before the burn on the relationship between vegetation recovery and soil temperature for three coastal marsh types were investigated. The water depth over the soil surface during in-situ burning was a key factor controlling marsh plant recovery. Both the 10- and 2-cm water depths were sufficient to protect marsh vegetation from burning impacts, with surface soil temperatures of fire significantly impeded the post-burn recovery of Spartina alterniflora and Sagittaria lancifolia but did not detrimentally affect the recovery of Spartina patens and Distichlis spicata. Oil type (crude vs diesel) and oil applied to the marsh soil surface (0.5 L x m(-2)) before the burn did not significantly affect plant recovery. Thus, recovery is species-specific when no surface water exists. Even water at the soil surface will most likely protect wetland plants from burning impact.

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across the Mariana Archipelago from 2014-03-24 to 2014-05-05 (NCEI Accession 0161168)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across the Hawaiian Archipelago from 2016-09-01 to 2016-09-27 (NCEI Accession 0161171)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

C2 Swan spectrum used as a molecular pyrometer in transferred arc and the influence noise to signal ratio on the temperature values

International Nuclear Information System (INIS)

Nassar, H

2014-01-01

The C 2 Swan system molecular emission spectrum is frequently observed in arc plasmas containing hydrocarbons. The spectra emitted from 5 kw in the transferred arc reactor at atmospheric pressure by CH 4 /CO 2 /Ar mixture are recorded with the help of an optical system consisting of a linear CCD array coupled with 2m spectrometer. The rotational temperature of 4300±300 K is found from the experimental Abel inverted spectra in the arc center after a point-to-point comparison of the spectrum with a computer simulated one. The influence of the noise to signal ratio has been studied, if the noise to signal ratio is about 10% we found an error of 7% at temperature 3000 K and 10% at 6000 K.

Can the tinnitus spectrum identify tinnitus subgroups?

NARCIS (Netherlands)

Heijneman, Karin M.; de Kleine, Emile; Wiersinga-Post, Esther; van Dijk, Pim

2013-01-01

The tinnitus spectrum is a psycho-acoustic metric of tinnitus. Previous work found a tight relation between the spectrum and the tone audiogram. This suggests that the spectrum and the audiogram provide essentially the same information, and the added value of the spectrum is limited. In order to

Imprint of spatial curvature on inflation power spectrum

International Nuclear Information System (INIS)

Masso, Eduard; Zsembinszki, Gabriel; Mohanty, Subhendra; Nautiyal, Akhilesh

2008-01-01

If the Universe had a large curvature before inflation there is a deviation from the scale invariant perturbations of the inflaton at the beginning of inflation. This may have some effect on the cosmic microwave background anisotropy at large angular scales. We calculate the density perturbations for both open and closed universe cases using the Bunch-Davies vacuum condition on the initial state. We use our power spectrum to calculate the temperature anisotropy spectrum and compare the results with the Wilkinson microwave anisotropy map five year data. We find that our power spectrum gives a lower quadrupole anisotropy when Ω-1>0, but matches the temperature anisotropy calculated from the standard Ratra-Peebles power spectrum at large l. The determination of spatial curvature from temperature anisotropy data is not much affected by the different power spectra which arise from the choice of different boundary conditions for the inflaton perturbation.

Influence of heat treatment and indenter tip material on depth sensing hardness tests at high temperatures of fusion relevant materials

International Nuclear Information System (INIS)

Bredl, Julian; Dany, Manuel; Albinski, Bartlomiej; Schneider, Hans-Christian; Kraft, Oliver

2015-01-01

Highlights: • Operation of a custom-made indentation device designed for test temperatures up to 650 °C and a remote handled operation in a Hot Cell. • Instrumented indentation and conventional hardness testing of unirradiated MANET II and EUROFER. • Comparison of diamond and sapphire as indenter tip materials. - Abstract: The instrumented indentation is a suitable method for testing of even small neutron-irradiated specimens. From the continuously recorded indentation depth and the indentation force, it is possible to deduce mechanical parameters of the tested material. In this paper, a brief description of the high temperature device is given and representative results are presented. In the study, unirradiated steels are investigated by instrumented indentation at temperatures up to 500 °C. It is shown that the hardness is highly depending on the testing-temperature and can be correlated to the results of conventional tensile testing experiments. A not negligible influence of the indenter tip material is observed. The results show the functionality of the high-temperature indentation device.

Influence of heat treatment and indenter tip material on depth sensing hardness tests at high temperatures of fusion relevant materials

Energy Technology Data Exchange (ETDEWEB)

Bredl, Julian, E-mail: julian.bredl@kit.edu; Dany, Manuel; Albinski, Bartlomiej; Schneider, Hans-Christian; Kraft, Oliver

2015-10-15

Highlights: • Operation of a custom-made indentation device designed for test temperatures up to 650 °C and a remote handled operation in a Hot Cell. • Instrumented indentation and conventional hardness testing of unirradiated MANET II and EUROFER. • Comparison of diamond and sapphire as indenter tip materials. - Abstract: The instrumented indentation is a suitable method for testing of even small neutron-irradiated specimens. From the continuously recorded indentation depth and the indentation force, it is possible to deduce mechanical parameters of the tested material. In this paper, a brief description of the high temperature device is given and representative results are presented. In the study, unirradiated steels are investigated by instrumented indentation at temperatures up to 500 °C. It is shown that the hardness is highly depending on the testing-temperature and can be correlated to the results of conventional tensile testing experiments. A not negligible influence of the indenter tip material is observed. The results show the functionality of the high-temperature indentation device.

Relativistic jet feedback - II. Relationship to gigahertz peak spectrum and compact steep spectrum radio galaxies

Science.gov (United States)

Bicknell, Geoffrey V.; Mukherjee, Dipanjan; Wagner, Alexander Y.; Sutherland, Ralph S.; Nesvadba, Nicole P. H.

2018-04-01

We propose that Gigahertz Peak Spectrum (GPS) and Compact Steep Spectrum (CSS) radio sources are the signposts of relativistic jet feedback in evolving galaxies. Our simulations of relativistic jets interacting with a warm, inhomogeneous medium, utilizing cloud densities and velocity dispersions in the range derived from optical observations, show that free-free absorption can account for the ˜ GHz peak frequencies and low-frequency power laws inferred from the radio observations. These new computational models replace a power-law model for the free-free optical depth a more fundamental model involving disrupted log-normal distributions of warm gas. One feature of our new models is that at early stages, the low-frequency spectrum is steep but progressively flattens as a result of a broader distribution of optical depths, suggesting that the steep low-frequency spectra discovered by Callingham et al. may possibly be attributed to young sources. We also investigate the inverse correlation between peak frequency and size and find that the initial location on this correlation is determined by the average density of the warm ISM. The simulated sources track this correlation initially but eventually fall below it, indicating the need for a more extended ISM than presently modelled. GPS and CSS sources can potentially provide new insights into the phenomenon of AGN feedback since their peak frequencies and spectra are indicative of the density, turbulent structure, and distribution of gas in the host galaxy.

Novel Cooperative Spectrum Sensing Methods And Their Limitations

DEFF Research Database (Denmark)

Kiilerich Pratas, Nuno

2012-01-01

$-calculus, denoted as Bounded Broadcast Calculus. This analysis is done over centralized, decentralized and relay aided topologies. The outcome of this analysis is a theorem where it is stated, which properties a protocol should have so that it can be deemed correct, i.e. that it performs as intended, over each...... source. The node selection scheme is proposed in a centralized and in a decentralized version. These versions can complement each other and therefore lead to a more robust cooperative spectrum sensing mechanism....

Thermal spectrum of pseudo-scalar glueballs and Debye screening mass from holography

Energy Technology Data Exchange (ETDEWEB)

Braga, Nelson R.F.; Ferreira, Luiz F. [Universidade Federal do Rio de Janeiro, Instituto de Fisica, Rio de Janeiro, RJ (Brazil)

2017-10-15

The finite temperature spectrum of pseudo-scalar glueballs in a plasma is studied using a holographic model. The 0{sup -+} glueball is represented by a pseudo-scalar (axion) field living in a five dimensional geometry that comes from a solution of Einstein equations for gravity coupled with a dilaton scalar field. The spectral function obtained from the model shows a clear peak corresponding to the quasi-particle ground state. Analyzing the variation of the position of the peak with temperature, we describe the thermal behavior of the Debye screening mass of the plasma. As a check of consistency, the zero temperature limit of the model is also investigated. The glueball masses obtained are consistent with previous lattice results. (orig.)

Magnetic-field enhancement beyond the skin-depth limit

Science.gov (United States)

Shin, Jonghwa; Park, Namkyoo; Fan, Shanhui; Lee, Yong-Hee

2010-02-01

Electric field enhancement has been actively studied recently and many metallic structures that are capable of locally enhancing electric field have been reported. The Babinet's principle can be utilized, especially in the form of Booker's extension, to transform the known electric field enhancing structures into magnetic field enhancing structures. The authors explain this transformation process and discuss the regime in which this principle breaks down. Unless the metals used can be well approximated with a PEC model, the principle's predictions fails to hold true. Authors confirm this aspect using numerical simulations based on realistic material parameters for actual metals. There is large discrepancy especially when the structural dimensions are comparable or less than the skin-depth at the wavelength of interest. An alternative way to achieve magnetic field enhancement is presented and the design of a connected bow-tie structure is proposed as an example. FDTD simulation results confirm the operation of the proposed structure.

Regulating the Emission Spectrum of CsPbBr3 from Green to Blue via Controlling the Temperature and Velocity of Microchannel Reactor

OpenAIRE

Yong Tang; Hanguang Lu; Longshi Rao; Zongtao Li; Xinrui Ding; Caiman Yan; Binhai Yu

2018-01-01

The ability to precisely obtain tunable spectrum of lead halide perovskite quantum dots (QDs) is very important for applications, such as in lighting and display. Herein, we report a microchannel reactor method for synthesis of CsPbBr3 QDs with tunable spectrum. By adjusting the temperature and velocity of the microchannel reactor, the emission peaks of CsPbBr3 QDs ranging from 520 nm to 430 nm were obtained, which is wider than that of QDs obtained in a traditional flask without changing hal...

Generating porosity spectrum of carbonate reservoirs using ultrasonic imaging log

Science.gov (United States)

Zhang, Jie; Nie, Xin; Xiao, Suyun; Zhang, Chong; Zhang, Chaomo; Zhang, Zhansong

2018-03-01

Imaging logging tools can provide us the borehole wall image. The micro-resistivity imaging logging has been used to obtain borehole porosity spectrum. However, the resistivity imaging logging cannot cover the whole borehole wall. In this paper, we propose a method to calculate the porosity spectrum using ultrasonic imaging logging data. Based on the amplitude attenuation equation, we analyze the factors affecting the propagation of wave in drilling fluid and formation and based on the bulk-volume rock model, Wyllie equation and Raymer equation, we establish various conversion models between the reflection coefficient β and porosity ϕ. Then we use the ultrasonic imaging logging and conventional wireline logging data to calculate the near-borehole formation porosity distribution spectrum. The porosity spectrum result obtained from ultrasonic imaging data is compared with the one from the micro-resistivity imaging data, and they turn out to be similar, but with discrepancy, which is caused by the borehole coverage and data input difference. We separate the porosity types by performing threshold value segmentation and generate porosity-depth distribution curves by counting with equal depth spacing on the porosity image. The practice result is good and reveals the efficiency of our method.

Thermal-depth matching in dynamic scene based on affine projection and feature registration

Science.gov (United States)

Wang, Hongyu; Jia, Tong; Wu, Chengdong; Li, Yongqiang

2018-03-01

This paper aims to study the construction of 3D temperature distribution reconstruction system based on depth and thermal infrared information. Initially, a traditional calibration method cannot be directly used, because the depth and thermal infrared camera is not sensitive to the color calibration board. Therefore, this paper aims to design a depth and thermal infrared camera calibration board to complete the calibration of the depth and thermal infrared camera. Meanwhile a local feature descriptors in thermal and depth images is proposed. The belief propagation matching algorithm is also investigated based on the space affine transformation matching and local feature matching. The 3D temperature distribution model is built based on the matching of 3D point cloud and 2D thermal infrared information. Experimental results show that the method can accurately construct the 3D temperature distribution model, and has strong robustness.

Heat flow of standard depth

International Nuclear Information System (INIS)

Cull, J.P.

1981-01-01

Secular and long-term periodic changes in surface temperature cause perturbations to the geothermal gradient which may be significant to depths of at least 1000 m, and major corrections are required to determine absolute values of heat flow from the Earth's interior. However, detailed climatic models remain contentious and estimates of error in geothermal gradients differ widely. Consequently, regions of anomalous heat flow which could contain geothermal resources may be more easily resolved by measuring relative values at a standard depth (e.g. 100 m) so that all data are subject to similar corrections. (orig./ME)

Shave-off depth profiling: Depth profiling with an absolute depth scale

International Nuclear Information System (INIS)

Nojima, M.; Maekawa, A.; Yamamoto, T.; Tomiyasu, B.; Sakamoto, T.; Owari, M.; Nihei, Y.

2006-01-01

Shave-off depth profiling provides profiling with an absolute depth scale. This method uses a focused ion beam (FIB) micro-machining process to provide the depth profile. We show that the shave-off depth profile of a particle reflected the spherical shape of the sample and signal intensities had no relationship to the depth. Through the introduction of FIB micro-sampling, the shave-off depth profiling of a dynamic random access memory (DRAM) tip was carried out. The shave-off profile agreed with a blue print from the manufacturing process. Finally, shave-off depth profiling is discussed with respect to resolutions and future directions

The limiting temperature of hot nuclei from microscopic equation of state

International Nuclear Information System (INIS)

Baldo, M.; Ferreira, L.S.; Nicotra, O.E.

2004-01-01

The limiting temperature T lim of a series of nuclei is calculated employing a set of microscopic nuclear equations of state (EOS's). It is shown that the value of T lim is sensitive to the nuclear matter equation of state used. Comparison with the values extracted in recent phenomenological analysis appears to favor a definite selection of EOS's. On the basis of this phenomenological analysis, it therefore seems possible to check the microscopic calculations of the nuclear EOS at finite temperature, which is hardly accessible through other experimental information

High Temperature Logging and Monitoring Instruments to Explore and Drill Deep into Hot Oceanic Crust.

Science.gov (United States)

Denchik, N.; Pezard, P. A.; Ragnar, A.; Jean-Luc, D.; Jan, H.

2014-12-01

Drilling an entire section of the oceanic crust and through the Moho has been a goal of the scientific community for more than half of a century. On the basis of ODP and IODP experience and data, this will require instruments and strategies working at temperature far above 200°C (reached, for example, at the bottom of DSDP/ODP Hole 504B), and possibly beyond 300°C. Concerning logging and monitoring instruments, progress were made over the past ten years in the context of the HiTI ("High Temperature Instruments") project funded by the european community for deep drilling in hot Icelandic geothermal holes where supercritical conditions and a highly corrosive environment are expected at depth (with temperatures above 374 °C and pressures exceeding 22 MPa). For example, a slickline tool (memory tool) tolerating up to 400°C and wireline tools up to 300°C were developed and tested in Icelandic high-temperature geothermal fields. The temperature limitation of logging tools was defined to comply with the present limitation in wireline cables (320°C). As part of this new set of downhole tools, temperature, pressure, fluid flow and casing collar location might be measured up to 400°C from a single multisensor tool. Natural gamma radiation spectrum, borehole wall ultrasonic images signal, and fiber optic cables (using distributed temperature sensing methods) were also developed for wireline deployment up to 300°C and tested in the field. A wireline, dual laterolog electrical resistivity tool was also developed but could not be field tested as part of HiTI. This new set of tools constitutes a basis for the deep exploration of the oceanic crust in the future. In addition, new strategies including the real-time integration of drilling parameters with modeling of the thermo-mechanical status of the borehole could be developed, using time-lapse logging of temperature (for heat flow determination) and borehole wall images (for hole stability and in-situ stress determination

Conductivity, temperature, depth, water quality and pigment data from R/V Bellows cruise BE-1311, 2012-12-12 to 2012-12-14 (NCEI Accession 0159411)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains conductivity, temperature, and depth data collected during R/V Bellows cruise BE-1311 of the offshore shelf of the Florida Panhandle Bight at...

Full-Scale Spectrum of Boundary-Layer Winds

DEFF Research Database (Denmark)

Larsén, Xiaoli Guo; Larsen, Søren Ejling; Lundtang Petersen, Erik

2016-01-01

and microscale gives the observed spectrum in the gap range, leading to a suggestion that mesoscale and microscale processes are uncorrelated. Depending on the relative strength of the two processes, the gap may be deep or shallow,visible or invisible. Generally, the depth of the gap decreases with height...

Explaining bathymetric diversity patterns in marine benthic invertebrates and demersal fishes: physiological contributions to adaptation of life at depth.

Science.gov (United States)

Brown, Alastair; Thatje, Sven

2014-05-01

Bathymetric biodiversity patterns of marine benthic invertebrates and demersal fishes have been identified in the extant fauna of the deep continental margins. Depth zonation is widespread and evident through a transition between shelf and slope fauna from the shelf break to 1000 m, and a transition between slope and abyssal fauna from 2000 to 3000 m; these transitions are characterised by high species turnover. A unimodal pattern of diversity with depth peaks between 1000 and 3000 m, despite the relatively low area represented by these depths. Zonation is thought to result from the colonisation of the deep sea by shallow-water organisms following multiple mass extinction events throughout the Phanerozoic. The effects of low temperature and high pressure act across hierarchical levels of biological organisation and appear sufficient to limit the distributions of such shallow-water species. Hydrostatic pressures of bathyal depths have consistently been identified experimentally as the maximum tolerated by shallow-water and upper bathyal benthic invertebrates at in situ temperatures, and adaptation appears required for passage to deeper water in both benthic invertebrates and demersal fishes. Together, this suggests that a hyperbaric and thermal physiological bottleneck at bathyal depths contributes to bathymetric zonation. The peak of the unimodal diversity-depth pattern typically occurs at these depths even though the area represented by these depths is relatively low. Although it is recognised that, over long evolutionary time scales, shallow-water diversity patterns are driven by speciation, little consideration has been given to the potential implications for species distribution patterns with depth. Molecular and morphological evidence indicates that cool bathyal waters are the primary site of adaptive radiation in the deep sea, and we hypothesise that bathymetric variation in speciation rates could drive the unimodal diversity-depth pattern over time. Thermal

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across the Northwestern Hawaiian Islands from 2015-07-31 to 2015-08-19 (NCEI Accession 0161170)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

Dynamic microscale temperature gradient in a gold nanorod solution measured by diffraction-limited nanothermometry

Energy Technology Data Exchange (ETDEWEB)

Li, Chengmingyue; Gan, Xiaosong; Li, Xiangping; Gu, Min, E-mail: mgu@swin.edu.au [Centre for Micro-Photonics, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia)

2015-09-21

We quantify the dynamic microscale temperature gradient in a gold nanorod solution using quantum-dot-based microscopic fluorescence nanothermometry. By incorporating CdSe quantum dots into the solution as a nanothermometer, precise temperature mapping with diffraction-limited spatial resolution and sub-degree temperature resolution is achieved. The acquired data on heat generation and dissipation show an excellent agreement with theoretical simulations. This work reveals an effective approach for noninvasive temperature regulation with localized nanoheaters in microfluidic environment.

Fatigue limit of polycrystalline zirconium oxide ceramics: Effect of grinding and low-temperature aging.

Science.gov (United States)

Pereira, G K R; Silvestri, T; Amaral, M; Rippe, M P; Kleverlaan, C J; Valandro, L F

2016-08-01

The following study aimed to evaluate the effect of grinding and low-temperature aging on the fatigue limit of Y-TZP ceramics for frameworks and monolithic restorations. Disc specimens from each ceramic material, Lava Frame (3M ESPE) and Zirlux FC (Ivoclar Vivadent) were manufactured according to ISO:6872-2008 and assigned in accordance with two factors: (1) "surface treatment"-without treatment (as-sintered, Ctrl), grinding with coarse diamond bur (181µm; Grinding); and (2) "low-temperature aging (LTD)" - presence and absence. Grinding was performed using a contra-angle handpiece under constant water-cooling. LTD was simulated in an autoclave at 134°C under 2-bar pressure for 20h. Mean flexural fatigue limits (20,000 cycles) were determined under sinusoidal loading using stair case approach. For Lava ceramic, it was observed a statistical increase after grinding procedure and different behavior after LTD stimuli (Ctrltemperature aging promoted a statistical increase in the fatigue limit (Ctrltemperature aging did not damage the fatigue limit values significantly for both materials evaluated, even though those conditions promoted increase in m-phase. Copyright © 2016 Elsevier Ltd. All rights reserved.

Imaging atoms from resonance fluorescence spectrum beyond the diffraction limit

Science.gov (United States)

Liao, Zeyang; Al-Amri, Mohammad; Zubairy, M. Suhail

2014-03-01

We calculate the resonance fluorescence spectrum of a linear chain of two-level atoms driven by a gradient coherent laser field. The result shows that we can determine the positions of atoms from the spectrum even when the atoms locate within subwavelength range and the dipole-dipole interaction is significant. This far-field resonance fluorescence localization microscopy method does not require point-by-point scanning and it may be more time-efficient. We also give a possible scheme to extract the position information in an extended region without requiring more peak power of laser. We also briefly discuss how to do a 2D imaging based on our scheme. This work is supported by grants from the King Abdulaziz City for Science and Technology (KACST) and the Qatar National Research Fund (QNRF) under the NPRP project.

Clinical Ethics in Gabon: The Spectrum of Clinical Ethical Issues Based on Findings from In-Depth Interviews at Three Public Hospitals

Science.gov (United States)

Sippel, Daniel; Marckmann, Georg; Ndzie Atangana, Etienne; Strech, Daniel

2015-01-01

Introduction Unlike issues in biomedical research ethics, ethical challenges arising in daily clinical care in Sub-Saharan African countries have not yet been studied in a systematic manner. However this has to be seen as a distinct entity as we argue in this paper. Our aim was to give an overview of the spectrum of clinical ethical issues and to understand what influences clinical ethics in the Sub-Saharan country of Gabon. Materials and Methods In-depth interviews with 18 health care professionals were conducted at three hospital sites in Gabon. Interview transcripts were analyzed using a grounded theory approach (open and axial coding), giving a qualitative spectrum of categories for clinical ethical issues. Validity was checked at a meeting with study participants and other health care experts in Gabon after analysis of the data. Results Twelve main categories (with 28 further-specified subcategories) for clinical ethical issues were identified and grouped under three core categories: A) micro level: “confidentiality and information”, “interpersonal, relational and behavioral issues”, “psychological strain of individuals”, and “scarce resources”; B) meso level: “structural issues of medical institutions”, “issues with private clinics”, “challenges connected to the family”, and “issues of education, training and competence”; and C) macro level: “influence of society, culture, religion and superstition”, “applicability of western medicine”, “structural issues on the political level”, and “legal issues”. Discussion Interviewees reported a broad spectrum of clinical ethical issues that go beyond challenges related to scarce financial and human resources. Specific socio-cultural, historical and educational backgrounds also played an important role. In fact these influences are central to an understanding of clinical ethics in the studied local context. Further research in the region is necessary to put our study into

OVII and Temperature Limits on the Local Hot Bubble

Science.gov (United States)

Pirtle, Robert; Petre, N.; McCammon, D.; Morgan, K.; Sauter, P.; Clavadetscher, K.; Fujimoto, R.; Hagihara, T.; Masui, K.; Mitsuda, K.; Takei, Y.; Wang, Q. D.; Yamasaki, N. Y.; Yao, Y.; Yoshino, T.

2013-01-01

The observed ¼-keV (ROSAT R12 band) X-ray background originates largely in a region of hot ionized gas roughly 100 pc in extent surrounding the Sun known as the Local Hot Bubble (LHB). The observed flux is quite uniform at low latitudes (|b| factors of 2 - 3. Charge exchange between highly charged ions in the Solar wind and interstellar neutral H and He moving through interplanetary space might provide a very roughly isotropic contribution about equal to the low- latitude flux (Koutroumpa et al. 2008), but cannot produce the enhancements. Correlations with the interstellar absorbing column show that some of these bright regions are apparently due to clumps of hot gas in the Galactic halo, while many of them show no correlation and must be due to extensions of the LHB (Kuntz & Snowden 2000, Bellm & Vaillancourt 2005). Global fits of simple plasma emission spectra give temperatures near 1.0 x 106 K for both LHB and halo emission, but the possibility of a substantial contamination by charge exchange could distort this result in unknown ways. Thermal excitation of O VII is strongly temperature dependent in this range, so we have tried to correlate O VII fluxes measured with Suzaku with variations in ¼-keV intensity from the ROSAT R12 band map to determine the temperature. We take eleven O VII intensity measurements from Yoshino et al. (2009), one from Masui et al. (2009), and an additional eighteen from archival Suzaku pointings and correlate these with the R12 band local and halo intensities as separated by Kunzt & Snowden (2000). The lack of detectable correlation in both cases strongly limits any O VII production by the material producing the enhancements, and upper limits to the temperatures are set. This work was supported in part by the National Science Foundation's REU program through NSF Award AST-1004881 and by NASA grant NNX09AF09G. *present address: Department of Physics, Lewis & Clark College, Portland, OR. This work was supported in part by the National

Classical limit for scalar fields at high temperature

International Nuclear Information System (INIS)

Buchmueller, W.; Jakovac, A.

1998-01-01

We study real-time correlation functions in scalar quantum field theories at temperature T=1/β. We show that the behaviour of soft, long-wavelength modes is determined by classical statistical field theory. The loss of quantum coherence is due to interactions with the soft modes of the thermal bath. The soft modes are separated from the hard modes by an infrared cutoff Λ<<1/(ℎβ). Integrating out the hard modes yields an effective theory for the soft modes. The infrared cutoff Λ controls corrections to the classical limit which are O(ℎβΛ). As an application, the plasmon damping rate is calculated. (orig.)

Muon-spin rotation (. mu. SR) study of the temperature dependence of the London penetration depth in copper oxide superconductors

Energy Technology Data Exchange (ETDEWEB)

Keller, H.; Kuendig, W.; Savic, I.M.; Simmler, H.; Staeuble-Puempin, B.; Warden, M.; Zech, D.; Zimmermann, P. (Physik-Inst., Univ. Zurich (Germany)); Kaldis, E.; Karpinski, J.; Rusiecki, S. (Lab. fuer Festkoerperphysik, ETH Zurich (Switzerland)); Brewer, J.H.; Riseman, T.M.; Schneider, J.W. (TRIUMF and Dept. of Physics, Univ. of British Columbia, Vancouver (Canada)); Maeno, Y.; Rossel, C. (IBM Research Div., Zurich Research Lab., Rueschlikon (Switzerland))

1991-12-01

A {mu}SR study of the temperature dependence of the London penetration depth {lambda} in sintered samples of YBa{sub 2}Cu{sub 3}O{sub x} (with various oxygen contents x), YBa{sub 2}Cu{sub 4}O{sub 8} and Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} is presented. It is found that the temperature behavior of {lambda} of all these cuprate superconductors is consistent with conventional s-wave pairing. However, there are significant differences concerning the exact temperature dependence of {lambda} in these materials. In YBa{sub 2}Cu{sub 3}O{sub x} with high x, the behavior of {lambda}(T) is well described by the two-fluid model (strong coupling), whereas {lambda}(T) in YBa{sub 2}Cu{sub 3}O{sub x} with low x, YBa{sub 2}Cu{sub 4}O{sub 8} and Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} is in better agreement with weak-coupling BCS theory. Possible reasons for the different temperature behavior of {lambda} in these materials are discussed. (orig.).

Approximate relationship between frequency-dependent skin depth ...

Indian Academy of Sciences (India)

results in the absence/limited number of borehole information, which is usually limited to information on the spot. ..... 2. /MN) · Ra (7). The processed average geological resistivity and depth of .... gical formation, it gives a clue to the behaviour.

Element depth profiles of porous silicon

International Nuclear Information System (INIS)

Kobzev, A.P.; Nikonov, O.A.; Kulik, M.; Zuk, J.; Krzyzanowska, H.; Ochalski, T.J.

1997-01-01

Element depth profiles of porous silicon were measured on the Van-de-Graaff accelerator in the energy range of 4 He + ions from 2 to 3.2 MeV. Application of complementary RBS, ERD and 16 O(α,α) 16 O nuclear reaction methods permits us to obtain: 1) the exact silicon, oxygen and hydrogen distribution in the samples, 2) the distribution of partial pore concentrations. The oxygen concentration in porous silicon reaches 30%, which allows one to assume the presence of silicon oxide in the pores and to explain the spectrum shift of luminescence into the blue area

Basalt Reactivity Variability with Reservoir Depth in Supercritical CO2 and Aqueous Phases

Energy Technology Data Exchange (ETDEWEB)

Schaef, Herbert T.; McGrail, B. Peter; Owen, Antionette T.

2011-04-01

Long term storage of CO{sub 2} in geologic formations is currently considered the most attractive option to reduce greenhouse gas emissions while continuing to utilize fossil fuels for energy production. Injected CO{sub 2} is expected to reside as a buoyant water-saturated supercritical fluid in contact with reservoir rock, the caprock system, and related formation waters. As was reported for the first time at the GHGT-9 conference, experiments with basalts demonstrated surprisingly rapid carbonate mineral formation occurring with samples suspended in the scCO{sub 2} phase. Those experiments were limited to a few temperatures and CO{sub 2} pressures representing relatively shallow (1 km) reservoir depths. Because continental flood basalts can extend to depths of 5 km or more, in this paper we extend the earlier results across a pressure-temperature range representative of these greater depths. Different basalt samples, including well cuttings from the borehole used in a pilot-scale basalt sequestration project (Eastern Washington, U.S.) and core samples from the Central Atlantic Magmatic Province (CAMP), were exposed to aqueous solutions in equilibrium with scCO{sub 2} and water-rich scCO{sub 2} at six different pressures and temperatures for select periods of time (30 to 180 days). Conditions corresponding to a shallow injection of CO{sub 2} (7.4 MPa, 34 C) indicate limited reactivity with basalt; surface carbonate precipitates were not easily identified on post-reacted basalt grains. Basalts exposed under identical times appeared increasingly more reacted with simulated depths. Tests, conducted at higher pressures (12.0 MPa) and temperatures (55 C), reveal a wide variety of surface precipitates forming in both fluid phases. Under shallow conditions tiny clusters of aragonite needles began forming in the wet scCO{sub 2} fluid, whereas in the CO{sub 2} saturated water, cation substituted calcite developed thin radiating coatings. Although these types of coatings

A Three-Dimensional Target Depth-Resolution Method with a Single-Vector Sensor.

Science.gov (United States)

Zhao, Anbang; Bi, Xuejie; Hui, Juan; Zeng, Caigao; Ma, Lin

2018-04-12

This paper mainly studies and verifies the target number category-resolution method in multi-target cases and the target depth-resolution method of aerial targets. Firstly, target depth resolution is performed by using the sign distribution of the reactive component of the vertical complex acoustic intensity; the target category and the number resolution in multi-target cases is realized with a combination of the bearing-time recording information; and the corresponding simulation verification is carried out. The algorithm proposed in this paper can distinguish between the single-target multi-line spectrum case and the multi-target multi-line spectrum case. This paper presents an improved azimuth-estimation method for multi-target cases, which makes the estimation results more accurate. Using the Monte Carlo simulation, the feasibility of the proposed target number and category-resolution algorithm in multi-target cases is verified. In addition, by studying the field characteristics of the aerial and surface targets, the simulation results verify that there is only amplitude difference between the aerial target field and the surface target field under the same environmental parameters, and an aerial target can be treated as a special case of a surface target; the aerial target category resolution can then be realized based on the sign distribution of the reactive component of the vertical acoustic intensity so as to realize three-dimensional target depth resolution. By processing data from a sea experiment, the feasibility of the proposed aerial target three-dimensional depth-resolution algorithm is verified.

Limit of grain refinement during ECAP process. Temperature influence

International Nuclear Information System (INIS)

Chuvil'deev, V.N.; Kopylov, V.I.; Nokhrin, A.V.; Makarov, I.M.; Lopatin, Yu.G.

2004-01-01

Experimental and theoretical study results are reported for the process of deformation grain refinement under severe plastic deformation. A generalization is made for experimental study results on deformation dispersing of unalloyed metals and aluminium and magnesium base alloys. The model is built that allows calculating the value of minimum grain size attained by the method of equal-channel angular pressing. The expressions are derived which describe the dependence of grain refinement limit on the nature of material and the temperature of severe plastic deformation [ru

Thermal stress analysis and the effect of temperature dependence of material properties on Doublet III limiter design

International Nuclear Information System (INIS)

McKelvey, T.E.; Koniges, A.E.; Marcus, F.; Sabado, M.; Smith, R.

1979-10-01

Temperature and thermal stress parametric design curves are presented for two materials selected for Doublet III primary limiter applications. INC X-750 is a candidate for the medium Z limiter design and ATJ graphite for the low Z design. The dependence of significant material properties on temperature is shown and the impact of this behavior on the decision to actively or passively cool the limiter is discussed

Long range surface plasmon resonance with ultra-high penetration depth for self-referenced sensing and ultra-low detection limit using diverging beam approach

Energy Technology Data Exchange (ETDEWEB)

Isaacs, Sivan, E-mail: sivan.isaacs@gmail.com; Abdulhalim, Ibrahim [Department of Electro-Optical Engineering and TheIlse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Beer Sheva 84105 (Israel); NEW CREATE Programme, School of Materials Science and Engineering, 1 CREATE Way, Research Wing, #02-06/08, Singapore 138602 (Singapore)

2015-05-11

Using an insulator-metal-insulator structure with dielectric having refractive index (RI) larger than the analyte, long range surface plasmon (SP) resonance exhibiting ultra-high penetration depth is demonstrated for sensing applications of large bioentities at wavelengths in the visible range. Based on the diverging beam approach in Kretschmann-Raether configuration, one of the SP resonances is shown to shift in response to changes in the analyte RI while the other is fixed; thus, it can be used as a built in reference. The combination of the high sensitivity, high penetration depth and self-reference using the diverging beam approach in which a dark line is detected of the high sensitivity, high penetration depth, self-reference, and the diverging beam approach in which a dark line is detected using large number of camera pixels with a smart algorithm for sub-pixel resolution, a sensor with ultra-low detection limit is demonstrated suitable for large bioentities.

Paraconductivity of three-dimensional amorphous superconductors: evidence for a short-wavelength cutoff in the fluctuation spectrum

International Nuclear Information System (INIS)

Johnson, W.L.

1977-10-01

Measurements of the temperature dependence and magnetic field dependence of the paraconductivity of a three dimensional amorphous superconductor are presented. The data are analyzed in terms of several current theories and are found to give good agreement for low fields and temperatures near T/sub c/. The paraconductivity falls well below predicted theoretical values in the high temperature and high field limits. This is attributed to the reduced role of high wavevector contributions to the paraconductivity. It is shown that the introduction of a short wavelength cutoff in the theoretical fluctuation spectrum provides a phenomelogical account of the discrepancy between theory and experiment

Dissolved oxygen, salinity, temperature, and depth data from bottle casts in the North Atlantic Ocean from 07 February 1987 to 18 February 1991 (NODC Accession 0000290)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Dissolved oxygen, salinity, temperature, and depth data were collected using bottle casts in the North Atlantic Ocean from February 7, 1987 to February 18, 1991....

Profile modifications in laser-driven temperature fronts using flux-limiters and delocalization models

Science.gov (United States)

Colombant, Denis; Manheimer, Wallace; Busquet, Michel

2004-11-01

A simple steady-state model using flux-limiters by Day et al [1] showed that temperature profiles could formally be double-valued. Stability of temperature profiles in laser-driven temperature fronts using delocalization models was also discussed by Prasad and Kershaw [2]. We have observed steepening of the front and flattening of the maximum temperature in laser-driven implosions [3]. Following the simple model first proposed in [1], we solve for a two-boundary value steady-state heat flow problem for various non-local heat transport models. For the more complicated models [4,5], we obtain the steady-state solution as the asymptotic limit of the time-dependent solution. Solutions will be shown and compared for these various models. 1.M.Day, B.Merriman, F.Najmabadi and R.W.Conn, Contrib. Plasma Phys. 36, 419 (1996) 2.M.K.Prasad and D.S.Kershaw, Phys. Fluids B3, 3087 (1991) 3.D.Colombant, W.Manheimer and M.Busquet, Bull. Amer. Phys. Soc. 48, 326 (2003) 4.E.M.Epperlein and R.W.Short, Phys. Fluids B3, 3092 (1991) 5.W.Manheimer and D.Colombant, Phys. Plasmas 11, 260 (2004)

Comparison of ASME pressure–temperature limits on the fracture probability for a pressurized water reactor pressure vessel

International Nuclear Information System (INIS)

Chou, Hsoung-Wei; Huang, Chin-Cheng

2017-01-01

Highlights: • P-T limits based on ASME K_I_a curve, K_I_C curve and RI method are presented. • Probabilistic and deterministic methods are used to evaluate P-T limits on RPV. • The feasibility of substituting P-T curves with more operational is demonstrated. • Warm-prestressing effect is critical in determining the fracture probability. - Abstract: The ASME Code Section XI-Appendix G defines the normal reactor startup (heat-up) and shut-down (cool-down) operation limits according to the fracture toughness requirement of reactor pressure vessel (RPV) materials. This paper investigates the effects of different pressure-temperature limit operations on structural integrity of a Taiwan domestic pressurized water reactor (PWR) pressure vessel. Three kinds of pressure-temperature limits based on different fracture toughness requirements – the K_I_a fracture toughness curve of ASME Section XI-Appendix G before 1998 editions, the K_I_C fracture toughness curve of ASME Section XI-Appendix G after 2001 editions, and the risk-informed revision method supplemented in ASME Section XI-Appendix G after 2013 editions, respectively, are established as the loading conditions. A series of probabilistic fracture mechanics analyses for the RPV are conducted employing ORNL’s FAVOR code considering various radiation embrittlement levels under these pressure-temperature limit conditions. It is found that the pressure-temperature operation limits which provide more operational flexibility may lead to higher fracture risks to the RPV. The cladding-induced shallow surface breaking flaws are the most critical and dominate the fracture probability of the RPV under pressure-temperature limit transients. Present study provides a risk-informed reference for the operation safety and regulation viewpoint of PWRs in Taiwan.

National Coral Reef Monitoring Program: Shallow Water Conductivity-Temperature-Depth (CTD) Profiles for selected locations across the Pacific Remote Island Areas from 2015-01-26 to 2015-04-28 (NCEI Accession 0162247)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Near-shore shallow water Conductivity-Temperature-Depth (CTD) surveys provided vertical profiles of temperature, salinity, and turbidity providing indications for...

Water vapor in the spectrum of the extrasolar planet HD 189733b. II. The eclipse

Energy Technology Data Exchange (ETDEWEB)

Crouzet, Nicolas [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); McCullough, Peter R. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Madhusudhan, Nikku, E-mail: crouzet@dunlap.utoronto.ca [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

2014-11-10

Spectroscopic observations of exoplanets are crucial to infer the composition and properties of their atmospheres. HD 189733b is one of the most extensively studied exoplanets and is a cornerstone for hot Jupiter models. In this paper, we report the dayside emission spectrum of HD 189733b in the wavelength range 1.1-1.7 μm obtained with the Hubble Space Telescope Wide Field Camera 3 (WFC3) in spatial scan mode. The quality of the data is such that even a straightforward analysis yields a high-precision Poisson noise-limited spectrum: the median 1σ uncertainty is 57 ppm per 0.02 μm bin. We also build a white-light curve correcting for systematic effects and derive an absolute eclipse depth of 96 ± 39 ppm. The resulting spectrum shows marginal evidence for water vapor absorption, but can also be well explained by a blackbody spectrum. However, the combination of these WFC3 data with previous Spitzer photometric observations is best explained by a dayside atmosphere of HD 189733b with no thermal inversion and a nearly solar or subsolar H{sub 2}O abundance in a cloud-free atmosphere. Alternatively, this apparent subsolar abundance may be the result of clouds or hazes that future studies need to investigate.

Dissolved oxygen, salinity, temperature, and depth data from bottle casts in the North Atlantic Ocean from 05 February 1973 to 19 August 1980 (NODC Accession 0000289)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Dissolved oxygen, salinity, temperature, and depth data were collected using bottle casts in the North Atlantic Ocean from February 5, 1973 to August 19, 1980. These...

Activation method for measurement of neutron spectrum parameters

International Nuclear Information System (INIS)

Efimov, B.V.; Demidov, A.M.; Ionov, V.S.; Konjaev, S.I.; Marin, S.V.; Bryzgalov, V.I.

2007-01-01

Experimental researches of spectrum parameters of neutrons at nuclear installations RRC KI are submitted. The installations have different designs of the cores, reflector, parameters and types of fuel elements. Measurements were carried out with use of the technique developed in RRC KI for irradiation resonance detectors UKD. The arrangement of detectors in the cores ensured possibility of measurement of neutron spectra with distinguished values of parameters. The spectrum parameters which are introduced by parametrical representation of a neutrons spectrum in the form corresponding to formalism Westcott. On experimental data were determinate absolute values of density neutron flux (DNF) in thermal and epithermal area of a spectrum (F t , f epi ), empirical dependence of temperature of neutron gas (Tn) on parameter of a rigidity of a spectrum (z), density neutron flux in transitional energy area of the spectrum. Dependences of spectral indexes of nuclides (UDy/UX), included in UKD, from a rigidity z and-or temperatures of neutron gas Tn are obtained.B Tools of mathematical processing of results are used for activation data and estimation of parameters of a spectrum (F t , f epi , z, Tn, UDy/UX). In the paper are presented some results of researches of neutron spectrum parameters of the nuclear installations (Authors)

Gamma ray energy spectrum of a buried radioactive source

Energy Technology Data Exchange (ETDEWEB)

Massey, N B

1957-07-01

Because of current attempts to utilize airborne gamma-ray scintillation spectrometers as a means of detecting and identifying buried radioactive mineral deposits, it has become important to study the effects of multiple scattering on the gamma-ray energy spectrum of a source buried in a semi-infinite medium. A series of ten experiments was made. First a scintillation detector was located in air at a fixed distance above a 250 microcurie cobalt-60 source suspended in a large tank. The level of water was raised from 25 cm below the source to 50 cm above, and the gamma-ray energy spectrum was observed. It was found that the high energy portion of the cobalt-60 spectrum remained identifiable even when the source was submerged more than five half-lengths. Further, the ratio of the counting rate of the total incident gamma radiation to the counting rate of the primary 1.33 MeV radiation was found to be very nearly linearly proportional to the depth of water cover. This leads to an empirical method for determining the depth of burial of a cobalt-60 point source. (author)

The Simulation of Temperature Field Based on 3D Modeling and Its Comparison versus Measured Temperature Distribution of Daqing Oilfield, NE China

Science.gov (United States)

Shi, Y.; Jiang, G.; Hu, S.

2017-12-01

Daqing, as the largest oil field of China with more than 50 years of exploration and production history for oil and gas, its geothermal energy utilization was started in 2000, with a main focus on district heating and direct use. In our ongoing study, data from multiple sources are collected, including BHT, DST, steady state temperature measurements in deep wells and thermophysical properties of formations. Based on these measurements, an elaborate investigation of the temperature field of Daqing Oilfield is made. Moreover, through exploration for oil and gas, subsurface geometry, depth, thickness and properties of the stratigraphic layers have been extensively delineated by well logs and seismic profiles. A 3D model of the study area is developed incorporating the information of structure, stratigraphy, basal heat flow, and petrophysical and thermophysical properties of strata. Based on the model, a simulation of the temperature field of Daqing Oilfield is generated. A purely conductive regime is presumed, as demonstrated by measured temperature log in deep wells. Wells W1, W2 and SK2 are used as key wells for model calibration. Among them, SK2, as part of the International Continental Deep Drilling Program, has a designed depth of 6400m, the steady state temperature measurement in the borehole has reached the depth of 4000m. The results of temperature distribution generated from simulation and investigation are compared, in order to evaluate the potential of applying the method to other sedimentary basins with limited borehole temperature measurements but available structural, stratigraphic and thermal regime information.

Mass current in 3He - A: Some exact representations and their London limit near zero temperature

International Nuclear Information System (INIS)

Malyshev, C.

1995-09-01

New representations for normal Green's function of the superfluid A-phase of helium-3 are obtained by an exact solution of the Dyson-Gor'kov equation. These representations result in new formulae for the mass current j-vector near zero temperature. Specific limiting cases for j-vector such ast the limit of lowest order in gradients, following the limit of zero temperature, and vice versa, are investigated. It is shown that the mass current previously known as j-vector = j-vector 0 , where j-vector 0 is an expression of first order in gradients, should be treated as a ''quasiclassical'' object in view of the approximations chosen. The parameter 1/χ implying the ''quasiclassics'', is a small quantity, as the London limit condition holds. Expansion of j-vector in powers of 1/χ is considered and first corrections to j-vector 0 are obtained at zero temperature, for two gauges of the order parameter. (author). 26 refs

Forming limit diagram of aluminum AA6063 tubes at high temperatures by bulge tests

International Nuclear Information System (INIS)

Hashemi, Seyed Jalal; Naeini, Hassan Moslemi; Liaghat, Gholamhossein; Tafti, Rooholla Azizi; Rahmani, Farzad

2014-01-01

A free bulge test and ductile fracture criteria were used to obtain the forming limit diagrams (FLD) of aluminum alloy AA6063 tubes at high temperatures. Ductile fracture criteria were calibrated using the results of uniaxial tension tests at various elevated temperatures and different strain rates through adjusting the Zener-Holloman parameter. High temperature free bulge test of tubes was simulated in finite element software Abaqus, and tube bursting was predicted using ductile fracture criteria under different loading paths. FLDs which were obtained from finite element simulation were compared to experimental results to select the most accurate criterion for prediction of forming limit diagram. According to the results, all studied ductile fracture criteria predict similarly when forming condition is close to the uniaxial tension, while Ayada criterion predicts the FLD at 473 K and 573 K very well.

Forming limit diagram of aluminum AA6063 tubes at high temperatures by bulge tests

Energy Technology Data Exchange (ETDEWEB)

Hashemi, Seyed Jalal; Naeini, Hassan Moslemi; Liaghat, Gholamhossein [Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Tafti, Rooholla Azizi [Yazd University, Yazd (Iran, Islamic Republic of); Rahmani, Farzad [Kar Higher Education Institute, Qazvin (Iran, Islamic Republic of)

2014-11-15

A free bulge test and ductile fracture criteria were used to obtain the forming limit diagrams (FLD) of aluminum alloy AA6063 tubes at high temperatures. Ductile fracture criteria were calibrated using the results of uniaxial tension tests at various elevated temperatures and different strain rates through adjusting the Zener-Holloman parameter. High temperature free bulge test of tubes was simulated in finite element software Abaqus, and tube bursting was predicted using ductile fracture criteria under different loading paths. FLDs which were obtained from finite element simulation were compared to experimental results to select the most accurate criterion for prediction of forming limit diagram. According to the results, all studied ductile fracture criteria predict similarly when forming condition is close to the uniaxial tension, while Ayada criterion predicts the FLD at 473 K and 573 K very well.

A Novel Method for Remote Depth Estimation of Buried Radioactive Contamination.

Science.gov (United States)

Ukaegbu, Ikechukwu Kevin; Gamage, Kelum A A

2018-02-08

Existing remote radioactive contamination depth estimation methods for buried radioactive wastes are either limited to less than 2 cm or are based on empirical models that require foreknowledge of the maximum penetrable depth of the contamination. These severely limits their usefulness in some real life subsurface contamination scenarios. Therefore, this work presents a novel remote depth estimation method that is based on an approximate three-dimensional linear attenuation model that exploits the benefits of using multiple measurements obtained from the surface of the material in which the contamination is buried using a radiation detector. Simulation results showed that the proposed method is able to detect the depth of caesium-137 and cobalt-60 contamination buried up to 40 cm in both sand and concrete. Furthermore, results from experiments show that the method is able to detect the depth of caesium-137 contamination buried up to 12 cm in sand. The lower maximum depth recorded in the experiment is due to limitations in the detector and the low activity of the caesium-137 source used. Nevertheless, both results demonstrate the superior capability of the proposed method compared to existing methods.

The Effect of Nitriding Treatment Variables on the Fatigue Limit of Alloy Steel (34crnimo6) Under High Cycle Fatigue

International Nuclear Information System (INIS)

Mohamed, J.; Al-Alkawi, H.; Salameh, M.

2009-01-01

The aim of this research is to improve the fatigue limit for alloy steel (34CrNiMo6) by salt bath nitriding process. This property is more effective to increase the fatigue life for parts which are used in continuous cyclic loading. All the fatigue tests were implemented before and after nitriding process under rotating bending. Constant and variable capacity stresses were applied before and after nitriding processes. The nitriding process were implemented in salt bath component at three different times (1, 2, 3) hr when temperature was constant at (555 degree centigrade). The depth of the nitride layer reached (0.24, 0.37, 0.5) mm. The nitriding process repeated of another specimens at the same times but the temperature was (600 degree centigrade), the layer depth reached (0.28, 0.41, 0.55) mm. The formation of a high nitrogen iron phases were detected with a layer of the hard chrome nitrides on the surface. The nitriding process is forming the barriers on the surface that resist the initiation and propagation of cracks, as well as generating the compressive residual stresses which delay the progress of fatigue crack. This research deduced that the nitriding processes increased the fatigue limit and this limit is proportional to the time of the nitriding process. When the time increased, the depth of nitride layer is increased, but decreased when the temperature increased to (600 degree centigrade) because of the formation of brittle phase,in spite of the increase in layer depth. (author)

Modulation depth analysis in fast pulsations of solar radio emission

International Nuclear Information System (INIS)

Chernov, G.P.; Kurts, Yu.; Akademie der Wissenschaften der DDR, Berlin

1990-01-01

A model of millisecond pulsations due to a pulsation regime of a whistler spectrum is confirmed by the statistical analysis of the modulation depth in five type IV bursts; a modulation depth distribution ΔI/I versus the period (p) grows linearly (with the different slope) up to the maximum at the value ΔI/I ≅ 0.5-0.6. The same dependence ΔI/I(p) for spikes, observed during the same events, testifies also in favour of this model. The overlap on fast pulsations of fiber bursts and of sudden reductions are displayed in the ΔI/I(p) distribution by diffuse tails which are naturally explained by the known models of this fine structure

Closed Loop Control of Penetration Depth during CO₂ Laser Lap Welding Processes

Directory of Open Access Journals (Sweden)

Antonio Ancona

2012-08-01

Full Text Available In this paper we describe a novel spectroscopic closed loop control system capable of stabilizing the penetration depth during laser welding processes by controlling the laser power. Our novel approach is to analyze the optical emission from the laser generated plasma plume above the keyhole, to calculate its electron temperature as a process-monitoring signal. Laser power has been controlled by using a quantitative relationship between the penetration depth and the plasma electron temperature. The sensor is able to correlate in real time the difference between the measured electron temperature and its reference value for the requested penetration depth. Accordingly the closed loop system adjusts the power, thus maintaining the penetration depth.

Extreme depth-of-field intraocular lenses

Science.gov (United States)

Baker, Kenneth M.

1996-05-01

A new technology brings the full aperture single vision pseudophakic eye's effective hyperfocal distance within the half-meter range. A modulated index IOL containing a subsurface zeroth order coherent microlenticular mosaic defined by an index gradient adds a normalizing function to the vergences or parallactic angles of incoming light rays subtended from field object points and redirects them, in the case of near-field images, to that of far-field images. Along with a scalar reduction of the IOL's linear focal range, this results in an extreme depth of field with a narrow depth of focus and avoids the focal split-up, halo, and inherent reduction in contrast of multifocal IOLs. A high microlenticular spatial frequency, which, while still retaining an anisotropic medium, results in a nearly total zeroth order propagation throughout the visible spectrum. The curved lens surfaces still provide most of the refractive power of the IOL, and the unique holographic fabrication technology is especially suitable not only for IOLs but also for contact lenses, artificial corneas, and miniature lens elements for cameras and other optical devices.

Temperature profile and water depth data collected from USS THACH using BT and XBT casts in the Persian Sea for 1987-11-21 (NODC Accession 8800016)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USS THACH in the Persian Sea. Data were collected from 21 November 1987 to 21...

Using of mass spectrum for prognosis of melting temperature of monatomic aliphatic spirits

International Nuclear Information System (INIS)

Vazhev, V. V.

2004-01-01

In present article researching possibility of prediction of melting temperature (MT) of monatomic aliphatic spirits with using mass-spectra as descriptors structure of molecules. Mass-spectra of 84 aliphatic spirits were used. Mass-spectra were preliminarily transformed on special formula before calculations for receiving work dates of descriptors. Calculations fulfilled with help of the computer program PROGROC. Quality of prediction characterized by coefficient of R-correlation between predicted and experimental dates MT and standard s-deviation. Coefficient of R-correlation between experimental and calculated dates account for 0.9785, standard s-deviation = 11.25 deg. C. Singly R and S for training and control excerpt equally 0.9789 and 11.31 deg. C, 0,9789 and 8.87 deg. C accordingly. Advantage of workable by us method lie in that, what on comparable with literature data of accuracy for prediction property is enough to have only mass-spectrum of substance

Depth and degree of melting of komatiites

Science.gov (United States)

Herzberg, Claude

1992-04-01

High pressure melting experiments have permitted new constraints to be placed on the depth and degree of partial melting of komatiites. Komatiites from Gorgona Island were formed by relatively low degrees of pseudoinvariant melting involving L + Ol + Opx + Cpx + Gt on the solidus at 40 kbar, about 130 km depth. Munro-type komatiites were separated from a harzburgite residue (L + Ol + Opx) at pressures that were poorly constrained, but were probably around 50 kbar, about 165 km depth; the degree of partial melting was less than 40 percent. Secular variations in the geochemistry of komatiites could have formed in response to a reduction in the temperature and pressure of melting with time. The 3.5 Ga Barberton komatiites and the 2.7 Ga Munro-type komatiities could have formed in plumes that were hotter than the present-day mantle by 500 deg and 300 deg, respectively. When excess temperatures are this size, melting is deeper and volcanism changes from basaltic to momatiitic. The komatiities from Gorgona Island, which are Mesozoic in age, may be representative of komatiities that are predicted to occur in oceanic plateaus of Cretaceous age throughout the Pacific (Storey et al., 1991).

Simulation of the spectrum (Co-60), Theratron Equinox, using the code Penelope

International Nuclear Information System (INIS)

Quispe V, N. Y.; Ballon P, C. I.; Vega R, J. L. J.; Santos F, C.

2017-10-01

Using the code Penelope (Penetration and Energy Loss of Positrons and Electrons) V. 2008, the spectrum of the Theratron Equinox cobalt unit, currently used at the Goyeneche Hospital in Arequipa (Peru), was obtained in the radiotherapy service. The Penmain program was used to obtain the spectrum that, together with the PENGEOM package included in the Penelope code, allowed to build complex structures with, in this case, the cobalt unit head essentially comprising the cobalt source and its collimators. The dose-to-depth percentage curves were also obtained in different sizes of irradiated fields of 5 x 5, 10 x 10 and 15 x 15 cm 2 for the cobalt spectrum obtained, in which is observed that there is greater dispersion for fields greater and more time of simulation was needed, being concordance of the results of the simulation, when comparing the experimentally obtained data of the dose with the ionization chamber in a water tank. The spectrum obtained was validated with the data of the ionization chamber in the determination of dose-to-depth percentage curves; it can be used as a reference to optimize the radiotherapy planning system in the simulation with equivalent body materials. (Author)

Formation of the UV Spectrum of Molecular Hydrogen in the Sun

Science.gov (United States)

Jaeggli, S. A.; Judge, P. G.; Daw, A. N.

2018-03-01

Ultraviolet (UV) lines of molecular hydrogen have been observed in solar spectra for almost four decades, but the behavior of the molecular spectrum and its implications for solar atmospheric structure are not fully understood. Data from the High-Resolution Telescope Spectrometer (HRTS) instrument revealed that H2 emission forms in particular regions, selectively excited by a bright UV transition region and chromospheric lines. We test the conditions under which H2 emission can originate by studying non-LTE models, sampling a broad range of temperature stratifications and radiation conditions. Stratification plays the dominant role in determining the population densities of H2, which forms in greatest abundance near the continuum photosphere. However, opacity due to the photoionization of Si and other neutrals determines the depth to which UV radiation can penetrate to excite the H2. Thus the majority of H2 emission forms in a narrow region, at about 650 km in standard one-dimensional (1D) models of the quiet Sun, near the τ = 1 opacity surface for the exciting UV radiation, generally coming from above. When irradiated from above using observed intensities of bright UV emission lines, detailed non-LTE calculations show that the spectrum of H2 seen in the quiet-Sun Solar Ultraviolet Measurement of Emitted Radiation atlas spectrum and HRTS light-bridge spectrum can be satisfactorily reproduced in 1D stratified atmospheres, without including three-dimensional or time-dependent thermal structures. A detailed comparison to observations from 1205 to 1550 Å is presented, and the success of this 1D approach to modeling solar UV H2 emission is illustrated by the identification of previously unidentified lines and upper levels in HRTS spectra.

Coherence length saturation at the low temperature limit in two-dimensional hole gas

Science.gov (United States)

Shan, Pujia; Fu, Hailong; Wang, Pengjie; Yang, Jixiang; Pfeiffer, L. N.; West, K. W.; Lin, Xi

2018-05-01

The plateau-plateau transition in the integer quantum Hall effect is studied in three Hall bars with different widths. The slopes of the Hall resistance as a function of magnetic field follow the scaling power law as expected in the plateau-plateau transition, and saturate at the low temperature limit. Surprisingly, the saturation temperature is irrelevant with the Hall bar size, which suggests that the saturation of the coherence length is intrinsic.

Stability of hydrocarbon systems at thermobaric conditions corresponding to depth down to 50 km

Science.gov (United States)

Kutcherov, V.; Kolesnikov, A.; Mukhina, E.; Serovaiskii, A.

2017-12-01

Most of the theoretical models show that crude oil stability is limited by the depth of 6-8 km (`oil window'). Commercial discovery of crude oil deposits on the depth more than 10 km in the different petroleum basins worldwide casts doubt on the validity of the above-mentioned theoretical calculations. Therefore, the question at which depth complex hydrocarbon systems could be stable is important not only from fundamental research point of view but has a great practical application. To answer this question a hydrocarbon mixture was investigated under thermobaric conditions corresponding to the conditions of the Earth's lower crust. Experiments were conducted by means of Raman Mössbauer spectroscopy. The results obtained show that the complex hydrocarbon systems could be stable and remain their qualitative and quantitative composition at temperature 320-450 °C and pressure 0.7-1.4 GPa. The oxidizing resistance of hydrocarbon system was tested in the modelled the Earth's crust surrounding. The hydrocarbon system stability at the presence of Fe2O3 strongly confirms that the Earth's crust oxygen fugacity does not influence on petroleum composition. The data obtained broaden our knowledge about the possible range of depths for crude oil and natural gas deposits in the Earth's crust and give us the possibility to revise the depth of petroleum deposits occurrence.

Atomistic simulation of femtosecond laser pulse interactions with a copper film: Effect of dependency of penetration depth and reflectivity on electron temperature

Science.gov (United States)

Amouye Foumani, A.; Niknam, A. R.

2018-01-01

The response of copper films to irradiation with laser pulses of fluences in the range of 100-6000 J/m2 is simulated by using a modified combination of a two-temperature model (TTM) and molecular dynamics (MD). In this model, the dependency of the pulse penetration depth and the reflectivity of the target on electron temperature are taken into account. Also, the temperature-dependent electron-phonon coupling factor, electron thermal conductivity, and electron heat capacity are used in the simulations. Based on this model, the dependence of the integral reflectivity on pulse fluence, the changes in the film thickness, and the evolution of density and electron and lattice temperatures are obtained. Moreover, snapshots that show the melting and disintegration processes are presented. The disintegration starts at a fluence of 4200 J/m2, which corresponds with an absorbed fluence of 616 J/m2. The calculated values of integral reflectivity are in good agreement with the experimental data. The inclusion of such temperature-dependent absorption models in the TTM-MD method would facilitate the comparison of experimental data with simulation results.

Testing the hadronic spectrum in the strange sector

International Nuclear Information System (INIS)

Parotto, P.

2017-01-01

Heavier resonances are continually being added to the hadronic spectrum from the Particle Data Group that follow an exponentially increasing mass spectrum. However, it has been suggested that even further states predicted from Quark Models are needed in the hadronic spectrum in order to improve the agreement between the hadron resonance gas model predictions and lattice QCD data. We find that the inclusion of such states with extrapolated branching ratios slightly decreases the freezeout temperature. To eliminate ambiguities, we introduce a first principle method to extract the freeze-out temperature for charged kaons from experimental data, which yields a lower bound of T fo ≳ 145 MeV for the highest collision energy at RHIC. (paper)

Method for the determination of technical specifications limiting temperature in EBR-II operation

International Nuclear Information System (INIS)

Chang, L.K.; Hill, D.J.; Ku, J.Y.

2004-01-01

The methodology and analysis procedure to qualify the Mark-V and Mark-VA fuels for the Experimental Breeder Reactor II are summarized in this paper. Fuel performance data and design safety criteria are essential for thermal-hydraulic analyses and safety evaluations. Normal and off-normal operation duty cycles and transient classifications are required for the safety assessment of the fuels. Design safety criteria for steady-state normal and transient off-normal operations were developed to ensure structural integrity of the fuel pin. The maximum allowable coolant outlet temperatures and powers of subassemblies for steady-state normal operation conditions were first determined in a row-by-row basis by a thermal-hydraulic and fuel damage analysis, in which a trial-and-error approach was used to predict the maximum subassembly coolant outlet temperatures and powers that satisfy the design safety criteria for steady-state normal operation conditions. The limiting steady-state temperature and power were then used as the initial subassembly thermal conditions for the off-normal transient analysis to assess the safety performance of the fuel pin for anticipated, unlikely and extremely unlikely events. If the design safety criteria for the off-normal events are not satisfied, then the initial steady-state subassembly temperatures and/or powers are reduced and an iterative procedure is employed until the design safety criteria for off-normal conditions are satisfied, and the initial subassembly outlet coolant temperature and power are the technical specification limits for reactor operation. (author)

Random spectrum loading of dental implants: An alternative approach to functional performance assessment.

Science.gov (United States)

Shemtov-Yona, K; Rittel, D

2016-09-01

The fatigue performance of dental implants is usually assessed on the basis of cyclic S/N curves. This neither provides information on the anticipated service performance of the implant, nor does it allow for detailed comparisons between implants unless a thorough statistical analysis is performed, of the kind not currently required by certification standards. The notion of endurance limit is deemed to be of limited applicability, given unavoidable stress concentrations and random load excursions, that all characterize dental implants and their service conditions. We propose a completely different approach, based on random spectrum loading, as long used in aeronautical design. The implant is randomly loaded by a sequence of loads encompassing all load levels it would endure during its service life. This approach provides a quantitative and comparable estimate of its performance in terms of lifetime, based on the very fact that the implant will fracture sooner or later, instead of defining a fatigue endurance limit of limited practical application. Five commercial monolithic Ti-6Al-4V implants were tested under cyclic, and another 5 under spectrum loading conditions, at room temperature and dry air. The failure modes and fracture planes were identical for all implants. The approach is discussed, including its potential applications, for systematic, straightforward and reliable comparisons of various implant designs and environments, without the need for cumbersome statistical analyses. It is believed that spectrum loading can be considered for the generation of new standardization procedures and design applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Climate reconstruction from borehole temperatures influenced by groundwater flow

Science.gov (United States)

Kurylyk, B.; Irvine, D. J.; Tang, W.; Carey, S. K.; Ferguson, G. A. G.; Beltrami, H.; Bense, V.; McKenzie, J. M.; Taniguchi, M.

2017-12-01

Borehole climatology offers advantages over other climate reconstruction methods because further calibration steps are not required and heat is a ubiquitous subsurface property that can be measured from terrestrial boreholes. The basic theory underlying borehole climatology is that past surface air temperature signals are reflected in the ground surface temperature history and archived in subsurface temperature-depth profiles. High frequency surface temperature signals are attenuated in the shallow subsurface, whereas low frequency signals can be propagated to great depths. A limitation of analytical techniques to reconstruct climate signals from temperature profiles is that they generally require that heat flow be limited to conduction. Advection due to groundwater flow can thermally `contaminate' boreholes and result in temperature profiles being rejected for regional climate reconstructions. Although groundwater flow and climate change can result in contrasting or superimposed thermal disturbances, groundwater flow will not typically remove climate change signals in a subsurface thermal profile. Thus, climate reconstruction is still possible in the presence of groundwater flow if heat advection is accommodated in the conceptual and mathematical models. In this study, we derive a new analytical solution for reconstructing surface temperature history from borehole thermal profiles influenced by vertical groundwater flow. The boundary condition for the solution is composed of any number of sequential `ramps', i.e. periods with linear warming or cooling rates, during the instrumented and pre-observational periods. The boundary condition generation and analytical temperature modeling is conducted in a simple computer program. The method is applied to reconstruct climate in Winnipeg, Canada and Tokyo, Japan using temperature profiles recorded in hydrogeologically active environments. The results demonstrate that thermal disturbances due to groundwater flow and climate

Opportunistic spectrum utilization in vehicular communication networks

CERN Document Server

Cheng, Nan

2016-01-01

This brief examines current research on improving Vehicular Networks (VANETs), examining spectrum scarcity due to the dramatic growth of mobile data traffic and the limited bandwidth of dedicated vehicular communication bands and the use of opportunistic spectrum bands to mitigate congestion. It reviews existing literature on the use of opportunistic spectrum bands for VANETs, including licensed and unlicensed spectrum bands and a variety of related technologies, such as cognitive radio, WiFi and device-to-device communications. Focused on analyzing spectrum characteristics, designing efficient spectrum exploitation schemes, and evaluating the date delivery performance when utilizing different opportunistic spectrum bands, the results presented in this brief provide valuable insights on improving the design and deployment of future VANETs.

Suppression of the sonic heat transfer limit in high-temperature heat pipes

Science.gov (United States)

Dobran, Flavio

1989-08-01

The design of high-performance heat pipes requires optimization of heat transfer surfaces and liquid and vapor flow channels to suppress the heat transfer operating limits. In the paper an analytical model of the vapor flow in high-temperature heat pipes is presented, showing that the axial heat transport capacity limited by the sonic heat transfer limit depends on the working fluid, vapor flow area, manner of liquid evaporation into the vapor core of the evaporator, and lengths of the evaporator and adiabatic regions. Limited comparisons of the model predictions with data of the sonic heat transfer limits are shown to be very reasonable, giving credibility to the proposed analytical approach to determine the effect of various parameters on the axial heat transport capacity. Large axial heat transfer rates can be achieved with large vapor flow cross-sectional areas, small lengths of evaporator and adiabatic regions or a vapor flow area increase in these regions, and liquid evaporation in the evaporator normal to the main flow.

Influences of increasing temperature on Indian wheat: quantifying limits to predictability

International Nuclear Information System (INIS)

Koehler, Ann-Kristin; Challinor, Andrew J; Hawkins, Ed; Asseng, Senthold

2013-01-01

As climate changes, temperatures will play an increasing role in determining crop yield. Both climate model error and lack of constrained physiological thresholds limit the predictability of yield. We used a perturbed-parameter climate model ensemble with two methods of bias-correction as input to a regional-scale wheat simulation model over India to examine future yields. This model configuration accounted for uncertainty in climate, planting date, optimization, temperature-induced changes in development rate and reproduction. It also accounts for lethal temperatures, which have been somewhat neglected to date. Using uncertainty decomposition, we found that fractional uncertainty due to temperature-driven processes in the crop model was on average larger than climate model uncertainty (0.56 versus 0.44), and that the crop model uncertainty is dominated by crop development. Simulations with the raw compared to the bias-corrected climate data did not agree on the impact on future wheat yield, nor its geographical distribution. However the method of bias-correction was not an important source of uncertainty. We conclude that bias-correction of climate model data and improved constraints on especially crop development are critical for robust impact predictions. (letter)

Model Atmosphere Spectrum Fit to the Soft X-Ray Outburst Spectrum of SS Cyg

Directory of Open Access Journals (Sweden)

V. F. Suleimanov

2015-02-01

Full Text Available The X-ray spectrum of SS Cyg in outburst has a very soft component that can be interpreted as the fast-rotating optically thick boundary layer on the white dwarf surface. This component was carefully investigated by Mauche (2004 using the Chandra LETG spectrum of this object in outburst. The spectrum shows broad ( ≈5 °A spectral features that have been interpreted as a large number of absorption lines on a blackbody continuum with a temperature of ≈250 kK. Because the spectrum resembles the photospheric spectra of super-soft X-ray sources, we tried to fit it with high gravity hot LTE stellar model atmospheres with solar chemical composition, specially computed for this purpose. We obtained a reasonably good fit to the 60–125 °A spectrum with the following parameters: Teff = 190 kK, log g = 6.2, and NH = 8 · 1019 cm−2, although at shorter wavelengths the observed spectrum has a much higher flux. The reasons for this are discussed. The hypothesis of a fast rotating boundary layer is supported by the derived low surface gravity.

An Analysis of Recent Measurements of the Temperature of the Cosmic Microwave Background Radiation

Science.gov (United States)

Smoot, G.; Levin, S. M.; Witebsky, C.; De Amici, G.; Rephaeli, Y.

1987-07-01

This paper presents an analysis of the results of recent temperature measurements of the cosmic microwave background radiation (CMBR). The observations for wavelengths longer than 0.1 cum are well fit by a blackbody spectrum at 2.74{+ or -}0.0w K; however, including the new data of Matsumoto et al. (1987) the result is no longer consistent with a Planckian spectrum. The data are described by a Thomson-distortion parameter u=0.021{+ or -}0.002 and temperature 2.823{+ or -}0.010 K at the 68% confidence level. Fitting the low-frequency data to a Bose-Einstein spectral distortion yields a 95% confidence level upper limit of 1.4 x 10{sup -2} on the chemical potential mu{sub 0}. These limits on spectral distortions place restrictions on a number of potentially interesting sources of energy release to the CMBR, including the hot intergalactic medium proposed as the source of the X-ray background.

WATER DEPTH and Other Data (NODC Accession 9400096)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD); and bathythermograph (XBT) data were collected as part of Distribution/Abundance of Marine Mammals in Gulf of Mexico...

Depth image enhancement using perceptual texture priors

Science.gov (United States)

Bang, Duhyeon; Shim, Hyunjung

2015-03-01

A depth camera is widely used in various applications because it provides a depth image of the scene in real time. However, due to the limited power consumption, the depth camera presents severe noises, incapable of providing the high quality 3D data. Although the smoothness prior is often employed to subside the depth noise, it discards the geometric details so to degrade the distance resolution and hinder achieving the realism in 3D contents. In this paper, we propose a perceptual-based depth image enhancement technique that automatically recovers the depth details of various textures, using a statistical framework inspired by human mechanism of perceiving surface details by texture priors. We construct the database composed of the high quality normals. Based on the recent studies in human visual perception (HVP), we select the pattern density as a primary feature to classify textures. Upon the classification results, we match and substitute the noisy input normals with high quality normals in the database. As a result, our method provides the high quality depth image preserving the surface details. We expect that our work is effective to enhance the details of depth image from 3D sensors and to provide a high-fidelity virtual reality experience.

EXAMINING THE BROADBAND EMISSION SPECTRUM OF WASP-19b: A NEW z-BAND ECLIPSE DETECTION

Energy Technology Data Exchange (ETDEWEB)

Zhou, George; Bayliss, Daniel D. R. [Research School of Astronomy and Astrophysics, Australian National University, Cotter Rd, Weston Creek, ACT 2611 (Australia); Kedziora-Chudczer, Lucyna; Bailey, Jeremy, E-mail: george@mso.anu.edu.au [School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia)

2013-09-10

WASP-19b is one of the most irradiated hot-Jupiters known. Its secondary eclipse is the deepest of all transiting planets and has been measured in multiple optical and infrared bands. We obtained a z-band eclipse observation with a measured depth of 0.080% {+-} 0.029%, using the 2 m Faulkes Telescope South, which is consistent with the results of previous observations. We combined our measurement of the z-band eclipse with previous observations to explore atmosphere models of WASP-19b that are consistent with its broadband spectrum. We use the VSTAR radiative transfer code to examine the effect of varying pressure-temperature profiles and C/O abundance ratios on the emission spectrum of the planet. We find that models with super-solar carbon enrichment best match the observations, which is consistent with previous model retrieval studies. We also include upper atmosphere haze as another dimension in the interpretation of exoplanet emission spectra and find that particles <0.5 {mu}m in size are unlikely to be present in WASP-19b.

A design of calibration single star simulator with adjustable magnitude and optical spectrum output system

Science.gov (United States)

Hu, Guansheng; Zhang, Tao; Zhang, Xuan; Shi, Gentai; Bai, Haojie

2018-03-01

In order to achieve multi-color temperature and multi-magnitude output, magnitude and temperature can real-time adjust, a new type of calibration single star simulator was designed with adjustable magnitude and optical spectrum output in this article. xenon lamp and halogen tungsten lamp were used as light source. The control of spectrum band and temperature of star was realized with different multi-beam narrow band spectrum with light of varying intensity. When light source with different spectral characteristics and color temperature go into the magnitude regulator, the light energy attenuation were under control by adjusting the light luminosity. This method can completely satisfy the requirements of calibration single star simulator with adjustable magnitude and optical spectrum output in order to achieve the adjustable purpose of magnitude and spectrum.

The Atacama Cosmology Telescope: A Measurement of the Primordial Power Spectrum

Science.gov (United States)

Hlozek, Renee; Dunkley, Joanna; Addison, Graeme; Appel, John William; Bond, J. Richard; Carvalho, C. Sofia; Das, Sudeep; Devlin, Mark J.; Duenner, Rolando; Essinger-Hileman, Thomas;

Fluence dependence of disorder depth profiles in Pb implanted Si

International Nuclear Information System (INIS)

Christodoulides, C.E.; Kadhim, N.J.; Carter, G.

1980-01-01

The total, depth integrated disorder, induced by Pb implantation into Si at room temperature, initially increases rapidly with implantation fluence and then reaches a quasi saturation level where the increase with fluence is slow. Measurements of the depth distributions of the disorder, using high resolution low angle exit Rutherford Backscattering/Channelling analysis, suggest that the quasi saturation results from overlapping of disordered zones generated deep in the tail of the disorder-depth profiles. The depth of the disordered solid-crystal boundary, xsub(D), increases with ion fluence PHI, according to the relation xsub(D) = x bar + f(PHI).σ, where x bar is the most probable projected depth and σ the projected standard deviation of disorder generation. It is shown that this relationship is consistent with an approximately Gaussian depth distribution of disorder production. (author)

Continental distribution as a forcing factor for global-scale temperature

Energy Technology Data Exchange (ETDEWEB)

Barron, E J; Thompson, S L; Hay, W W

1984-08-16

Since the advent of the continental drift hypothesis, changing continental geometries have been proposed as an explanation for long-term temperature variability. The climatic influence of a few specific past geographies has been investigated quantitatively, but these studies do not indicate the potential temperature variability due to continental positions. This problem has been examined only with simple climate models having limiting assumptions such as no cloud cover. Here idealized continental geometries are used as boundary conditions in a simulation using a general circulation model (GCM) of the atmosphere. The range in model simulated globally-averaged surface temperature is 7.4 K with a difference in polar surface temperature of up to 34 K. The simulations suggest a substantial climatic sensitivity to continental positions with the coldest global climate when land masses are in high latitudes. Although the simulations have not captured theoretical limits of climatic variability due to continental positions, present-day geography is near the cold end of this spectrum. 20 references, 1 figure.

RF safety assessment of a bilateral four-channel transmit/receive 7 Tesla breast coil: SAR versus tissue temperature limits.

Science.gov (United States)

Fiedler, Thomas M; Ladd, Mark E; Bitz, Andreas K

2017-01-01

The purpose of this work was to perform an RF safety evaluation for a bilateral four-channel transmit/receive breast coil and to determine the maximum permissible input power for which RF exposure of the subject stays within recommended limits. The safety evaluation was done based on SAR as well as on temperature simulations. In comparison to SAR, temperature is more directly correlated with tissue damage, which allows a more precise safety assessment. The temperature simulations were performed by applying three different blood perfusion models as well as two different ambient temperatures. The goal was to evaluate whether the SAR and temperature distributions correlate inside the human body and whether SAR or temperature is more conservative with respect to the limits specified by the IEC. A simulation model was constructed including coil housing and MR environment. Lumped elements and feed networks were modeled by a network co-simulation. The model was validated by comparison of S-parameters and B 1 + maps obtained in an anatomical phantom. Three numerical body models were generated based on 3 Tesla MRI images to conform to the coil housing. SAR calculations were performed and the maximal permissible input power was calculated based on IEC guidelines. Temperature simulations were performed based on the Pennes bioheat equation with the power absorption from the RF simulations as heat source. The blood perfusion was modeled as constant to reflect impaired patients as well as with a linear and exponential temperature-dependent increase to reflect two possible models for healthy subjects. Two ambient temperatures were considered to account for cooling effects from the environment. The simulation model was validated with a mean deviation of 3% between measurement and simulation results. The highest 10 g-averaged SAR was found in lung and muscle tissue on the right side of the upper torso. The maximum permissible input power was calculated to be 17 W. The

Computer simulation of temperature-dependent growth of fractal and compact domains in diluted Ising models

DEFF Research Database (Denmark)

Sørensen, Erik Schwartz; Fogedby, Hans C.; Mouritsen, Ole G.

1989-01-01

temperature are studied as functions of temperature, time, and concentration. At zero temperature and high dilution, the growing solid is found to have a fractal morphology and the effective fractal exponent D varies with concentration and ratio of time scales of the two dynamical processes. The mechanism...... responsible for forming the fractal solid is shown to be a buildup of a locally high vacancy concentration in the active growth zone. The growth-probability measure of the fractals is analyzed in terms of multifractality by calculating the f(α) spectrum. It is shown that the basic ideas of relating...... probability measures of static fractal objects to the growth-probability distribution during formation of the fractal apply to the present model. The f(α) spectrum is found to be in the universality class of diffusion-limited aggregation. At finite temperatures, the fractal solid domains become metastable...

Thermoluminescent system for low temperatures

International Nuclear Information System (INIS)

Rosa, L.A.R. da; Caldas, L.V.E.; Leite, N.G.

1988-09-01

A system for measurements of the thermoluminescent glow curve, the thermoluminescent emission spectrum and the optical absorption spectrum of solid samples, from liquid nitrogen temperature up to 473 K, is reported. A specially designed temperature programmer provides a linear heating of the sample at a wide range of selectable heating rates, as also long term steady-state temperatures for annealing and isothermal decay studies. The system operates at a pressure of 1.33 x 10 -3 Pa. Presently it is being used for lithium fluoride low temperature thermoluminescent studies. (author) [pt

BAROMETRIC PRESSURE and Other Data from WECOMA and Other Platforms From NE Pacific (limit-180) from 19930607 to 19930920 (NODC Accession 9500100)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD) and other data were collected in NE Pacific (limit-180) as part of Eastern Boundary Currents Accelerated Research...

Depth profile measurement with lenslet images of the plenoptic camera

Science.gov (United States)

Yang, Peng; Wang, Zhaomin; Zhang, Wei; Zhao, Hongying; Qu, Weijuan; Zhao, Haimeng; Asundi, Anand; Yan, Lei

2018-03-01

An approach for carrying out depth profile measurement of an object with the plenoptic camera is proposed. A single plenoptic image consists of multiple lenslet images. To begin with, these images are processed directly with a refocusing technique to obtain the depth map, which does not need to align and decode the plenoptic image. Then, a linear depth calibration is applied based on the optical structure of the plenoptic camera for depth profile reconstruction. One significant improvement of the proposed method concerns the resolution of the depth map. Unlike the traditional method, our resolution is not limited by the number of microlenses inside the camera, and the depth map can be globally optimized. We validated the method with experiments on depth map reconstruction, depth calibration, and depth profile measurement, with the results indicating that the proposed approach is both efficient and accurate.

Zero Thermal Noise in Resistors at Zero Temperature

Science.gov (United States)

Kish, Laszlo B.; Niklasson, Gunnar A.; Granqvist, Claes-Göran

2016-06-01

The bandwidth of transistors in logic devices approaches the quantum limit, where Johnson noise and associated error rates are supposed to be strongly enhanced. However, the related theory — asserting a temperature-independent quantum zero-point (ZP) contribution to Johnson noise, which dominates the quantum regime — is controversial and resolution of the controversy is essential to determine the real error rate and fundamental energy dissipation limits of logic gates in the quantum limit. The Callen-Welton formula (fluctuation-dissipation theorem) of voltage and current noise for a resistance is the sum of Nyquist’s classical Johnson noise equation and a quantum ZP term with a power density spectrum proportional to frequency and independent of temperature. The classical Johnson-Nyquist formula vanishes at the approach of zero temperature, but the quantum ZP term still predicts non-zero noise voltage and current. Here, we show that this noise cannot be reconciled with the Fermi-Dirac distribution, which defines the thermodynamics of electrons according to quantum-statistical physics. Consequently, Johnson noise must be nil at zero temperature, and non-zero noise found for certain experimental arrangements may be a measurement artifact, such as the one mentioned in Kleen’s uncertainty relation argument.

The electron temperature gradient instability in presence of a limiter with tilted plates

International Nuclear Information System (INIS)

Farina, D.; Pozzoli, R.; Ryutov, D.

1994-01-01

The analysis of the electron temperature gradient instability in the scrape-off layer is generalized to the case of non-orthogonal intersections of the magnetic field with the wall surface, a situation which is most typical for a tokamak with a limiter. (orig.)

Temperature profile and water depth data collected from USCGC HARRIOT LANE using BT and XBT casts in the NW Atlantic Ocean for 1987-05-31 (NODC Accession 8700225)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USCGC Harriot Lane in the Northwest Atlantic Ocean and TOGA Area - Atlantic...

The annihilation spectrum of relatiVistic electron-positron plasma

International Nuclear Information System (INIS)

Aragonyan, F.A.; Atoyan, A.M.; Syunyaev, R.A.

1980-01-01

The annihilation spectrum of isotropically distributed monoenergetic electrons and positrons is obtained. The spectrum of the (e + e - ) plasma is analyzed in a large range of plasma temperatures. The comparison of transitions peratures. The comparison of transitions intensities of annihilation radiation and bremsstrahlung shows that for temperatures kT 2 (e + e - ) plasma is cooled mainly due to annihilation. The case of the fast positron annihilation on the rest electrons also considered. The possible astrophysical applications are discussed [ru

Performance analysis of distributed beamforming in a spectrum sharing system

KAUST Repository

Yang, Liang

2013-05-01

In this paper, we consider a distributed beamforming scheme (DBF) in a spectrum sharing system where multiple secondary users share the spectrum with some licensed primary users under an interference temperature constraint. We assume that the DBF is applied at the secondary users. We first consider optimal beamforming and compare it with the user selection scheme in terms of the outage probability and bit error rate performance metrics. Since perfect feedback is difficult to obtain, we then investigate a limited feedback DBF scheme and develop an analysis for a random vector quantization design algorithm. Specifically, the approximate statistics functions of the squared inner product between the optimal and quantized vectors are derived. With these statistics, we analyze the outage performance. Furthermore, the effects of channel estimation error and number of primary users on the system performance are investigated. Finally, optimal power adaptation and cochannel interference are considered and analyzed. Numerical and simulation results are provided to illustrate our mathematical formalism and verify our analysis. © 2012 IEEE.

TRENDS IN ESTIMATED MIXING DEPTH DAILY MAXIMUMS

Energy Technology Data Exchange (ETDEWEB)

Buckley, R; Amy DuPont, A; Robert Kurzeja, R; Matt Parker, M

2007-11-12

Mixing depth is an important quantity in the determination of air pollution concentrations. Fireweather forecasts depend strongly on estimates of the mixing depth as a means of determining the altitude and dilution (ventilation rates) of smoke plumes. The Savannah River United States Forest Service (USFS) routinely conducts prescribed fires at the Savannah River Site (SRS), a heavily wooded Department of Energy (DOE) facility located in southwest South Carolina. For many years, the Savannah River National Laboratory (SRNL) has provided forecasts of weather conditions in support of the fire program, including an estimated mixing depth using potential temperature and turbulence change with height at a given location. This paper examines trends in the average estimated mixing depth daily maximum at the SRS over an extended period of time (4.75 years) derived from numerical atmospheric simulations using two versions of the Regional Atmospheric Modeling System (RAMS). This allows for differences to be seen between the model versions, as well as trends on a multi-year time frame. In addition, comparisons of predicted mixing depth for individual days in which special balloon soundings were released are also discussed.

Influence of structural disorder on low-temperature behavior of penetration depth in electron-doped high-TC thin films

International Nuclear Information System (INIS)

Lanfredi, A.J.C.; Sergeenkov, S.; Araujo-Moreira, F.M.

2006-01-01

To probe the influence of structural disorder on low-temperature behavior of magnetic penetration depth, λ(T), in electron-doped high-T C superconductors, a comparative study of high-quality Pr 1.85 Ce 0.15 CuO 4 (PCCO) and Sm 1.85 Ce 0.15 CuO 4 (SCCO) thin films is presented. The λ(T) profiles are extracted from conductance-voltage data using a highly-sensitive home-made mutual-inductance technique. The obtained results confirm a d-wave pairing mechanism in both samples (with nodal gap parameter Δ 0 /k B T C =2.0 and 2.1 for PCCO and SCCO films, respectively), substantially modified by impurity scattering (which is more noticeable in less homogeneous SCCO films) at the lowest temperatures. More precisely, Δλ(T)=λ(T)-λ(0) is found to follow the Goldenfeld-Hirschfeld interpolation formulae Δλ(T)/λ(0)=AT 2 /(T+T 0 ) with T 0 =ln(2)k B Γ 1/2 Δ 0 1/2 being the crossover temperature which demarcates pure and impure scattering processes (T 0 /T C =0.13 and 0.26 for PCCO and SCCO films, respectively). The value of the extracted impurity scattering rate Γ correlates with the quality of our samples and is found to be much higher in less homogeneous films with lower T C

Temperature profile and water depth data collected from COCHRANE in the South China Sea and other seas from 09 January 1987 to 22 February 1987 (NODC Accession 8700095)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT from the COCHRANE in the South China and other seas. Data were collected from 09 January...

Depth-profiling using X-ray photoelectron spectroscopy

International Nuclear Information System (INIS)

Pijolat, M.; Hollinger, G.

1980-12-01

The possibilities of X-ray photoelectron spectroscopy (or ESCA) for depth-profiling into shallow depths (approximately 10-100 A) have been studied. The method of ion-sputtering removal has first been investigated in order to improve its depth-resolution (approximately 50-150 A). A procedure which eliminates the effects due to the resolution function of the instrumental probe (analysed depth approximately 50 A) has been settled; but it is not yet sufficient, and the sputter - broadening due to the ion-induced damages must be taken into account (broadening function approximately 50 A for approximately 150 A removal). Because of serious difficulties in estimating the broadening function an alternative is to develop non destructive methods, so a new method based on the dependence of the analysed depth with the electron emission angle is presented. The extraction of the concentration profile from angular distribution experiments is achieved, in the framework of a flat-layer model, by minimizing the difference between theoretical and experimental relative intensities. The applicability and limitations of the method are discussed on the basis of computer simulation results. The depth probed is of the order of 3 lambda (lambda being the value of the inelastic mean free path, typically 10-20 A) and the depth-resolution is of the order of lambda/3 [fr

Resonance spectrum of near-extremal Kerr black holes in the eikonal limit

International Nuclear Information System (INIS)

Hod, Shahar

2012-01-01

The fundamental resonances of rapidly rotating Kerr black holes in the eikonal limit are derived analytically. We show that there exists a critical value, μ c =√((15-√(193))/2 ), for the dimensionless ratio μ≡m/l between the azimuthal harmonic index m and the spheroidal harmonic index l of the perturbation mode, above which the perturbations become long lived. In particular, it is proved that above μ c the imaginary parts of the quasinormal frequencies scale like the black-hole temperature: ω I (n;μ>μ c )=2πT BH (n+1/2 ). This implies that for perturbations modes in the interval μ c I of the black hole becomes extremely long as the extremal limit T BH →0 is approached. A generalization of the results to the case of scalar quasinormal resonances of near-extremal Kerr-Newman black holes is also provided. In particular, we prove that only black holes that rotate fast enough (with MΩ≥2/5 , where M and Ω are the black-hole mass and angular velocity, respectively) possess this family of remarkably long-lived perturbation modes.

Thermal neutron spectrum distribution in TRIGA fuels

International Nuclear Information System (INIS)

Gui Ah Auu; Harasawa, Susumu; An, Shigehiro

1989-01-01

The dependence of thermal neutron spectrum in TRIGA fuel cell on fuel temperature and TRIGA fuel types were studied using LIBP and THERMOS codes. Some characteristics of the TRIGA fuel including its prompt negative temperature coefficient of reactivity were explained using the results of the study. (author)

Estimation of bare soil surface temperature from air temperature and ...

African Journals Online (AJOL)

Soil surface temperature has critical influence on climate, agricultural and hydrological activities since it serves as a good indicator of the energy budget of the earth's surface. Two empirical models for estimating soil surface temperature from air temperature and soil depth temperature were developed. The coefficient of ...

Thermodynamics Far from the Thermodynamic Limit.

Science.gov (United States)

de Miguel, Rodrigo; Rubí, J Miguel

2017-11-16

Understanding how small systems exchange energy with a heat bath is important to describe how their unique properties can be affected by the environment. In this contribution, we apply Landsberg's theory of temperature-dependent energy levels to describe the progressive thermalization of small systems as their spectrum is perturbed by a heat bath. We propose a mechanism whereby the small system undergoes a discrete series of excitations and isentropic spectrum adjustments leading to a final state of thermal equilibrium. This produces standard thermodynamic results without invoking system size. The thermal relaxation of a single harmonic oscillator is analyzed as a model example of a system with a quantized spectrum than can be embedded in a thermal environment. A description of how the thermal environment affects the spectrum of a small system can be the first step in using environmental factors, such as temperature, as parameters in the design and operation of nanosystem properties.

Moisture rivals temperature in limiting photosynthesis by trees establishing beyond their cold-edge range limit under ambient and warmed conditions

Science.gov (United States)

Moyes, Andrew B.; Germino, Matthew J.; Kueppers, Lara M.

2015-01-01

Climate change is altering plant species distributions globally, and warming is expected to promote uphill shifts in mountain trees. However, at many cold-edge range limits, such as alpine treelines in the western United States, tree establishment may be colimited by low temperature and low moisture, making recruitment patterns with warming difficult to predict.

Nuclear shell effects at high temperatures

International Nuclear Information System (INIS)

Davidson, N.J.; Miller, H.G.

1993-01-01

In discussing the disappearance of nuclear shell effects at high temperatures, it is important to distinguish between the ''smearing out'' of the single-particle spectrum with increasing temperature and the vanishing of shell related structures in many-body quantities such as the excitation energy per nucleon. We propose a semiempirical method to obtain an upper bound on the temperature required to smooth the single-particle spectrum, and point out that shell effects in many-body parameters may persist above this temperature. We find that the temperature required to smear out the single-particle spectrum is approximately 1 MeV for heavy nuclei (A approx-gt 150) and about 3--4 MeV for light nuclei (A approx-lt 50), in reasonable agreement with the estimate of 41/πA 1/3 obtained from calculations with harmonic oscillator potentials. These temperatures correspond to many-body excitation energies of approximately 20 and 60 MeV, respectively

Next Generation Nuclear Plant Defense-in-Depth Approach

International Nuclear Information System (INIS)

Wallace, Edward G.; Fleming, Karl N.; Burns, Edward M.

2009-01-01

The purpose of this paper is to (1) document the definition of defense-in-depth and the pproach that will be used to assure that its principles are satisfied for the NGNP project and (2) identify the specific questions proposed for preapplication discussions with the NRC. Defense-in-depth is a safety philosophy in which multiple lines of defense and conservative design and evaluation methods are applied to assure the safety of the public. The philosophy is also intended to deliver a design that is tolerant to uncertainties in knowledge of plant behavior, component reliability or operator performance that might compromise safety. This paper includes a review of the regulatory foundation for defense-in-depth, a definition of defense-in-depth that is appropriate for advanced reactor designs based on High Temperature Gas-cooled Reactor (HTGR) technology, and an explanation of how this safety philosophy is achieved in the NGNP.

Sparse random matrices: The eigenvalue spectrum revisited

International Nuclear Information System (INIS)

Semerjian, Guilhem; Cugliandolo, Leticia F.

2003-08-01

We revisit the derivation of the density of states of sparse random matrices. We derive a recursion relation that allows one to compute the spectrum of the matrix of incidence for finite trees that determines completely the low concentration limit. Using the iterative scheme introduced by Biroli and Monasson [J. Phys. A 32, L255 (1999)] we find an approximate expression for the density of states expected to hold exactly in the opposite limit of large but finite concentration. The combination of the two methods yields a very simple geometric interpretation of the tails of the spectrum. We test the analytic results with numerical simulations and we suggest an indirect numerical method to explore the tails of the spectrum. (author)

Numerical and experimental results on the spectral wave transfer in finite depth

Science.gov (United States)

Benassai, Guido

2016-04-01

Determination of the form of the one-dimensional surface gravity wave spectrum in water of finite depth is important for many scientific and engineering applications. Spectral parameters of deep water and intermediate depth waves serve as input data for the design of all coastal structures and for the description of many coastal processes. Moreover, the wave spectra are given as an input for the response and seakeeping calculations of high speed vessels in extreme sea conditions and for reliable calculations of the amount of energy to be extracted by wave energy converters (WEC). Available data on finite depth spectral form is generally extrapolated from parametric forms applicable in deep water (e.g., JONSWAP) [Hasselmann et al., 1973; Mitsuyasu et al., 1980; Kahma, 1981; Donelan et al., 1992; Zakharov, 2005). The present paper gives a contribution in this field through the validation of the offshore energy spectra transfer from given spectral forms through the measurement of inshore wave heights and spectra. The wave spectra on deep water were recorded offshore Ponza by the Wave Measurement Network (Piscopia et al.,2002). The field regressions between the spectral parameters, fp and the nondimensional energy with the fetch length were evaluated for fetch-limited sea conditions. These regressions gave the values of the spectral parameters for the site of interest. The offshore wave spectra were transfered from the measurement station offshore Ponza to a site located offshore the Gulf of Salerno. The offshore local wave spectra so obtained were transfered on the coastline with the TMA model (Bouws et al., 1985). Finally the numerical results, in terms of significant wave heights, were compared with the wave data recorded by a meteo-oceanographic station owned by Naples Hydrographic Office on the coastline of Salerno in 9m depth. Some considerations about the wave energy to be potentially extracted by Wave Energy Converters were done and the results were discussed.

The Global Terrestrial Network for Permafrost Database: metadata statistics and prospective analysis on future permafrost temperature and active layer depth monitoring site distribution

Science.gov (United States)

Biskaborn, B. K.; Lanckman, J.-P.; Lantuit, H.; Elger, K.; Streletskiy, D. A.; Cable, W. L.; Romanovsky, V. E.

2015-03-01

The Global Terrestrial Network for Permafrost (GTN-P) provides the first dynamic database associated with the Thermal State of Permafrost (TSP) and the Circumpolar Active Layer Monitoring (CALM) programs, which extensively collect permafrost temperature and active layer thickness data from Arctic, Antarctic and Mountain permafrost regions. The purpose of the database is to establish an "early warning system" for the consequences of climate change in permafrost regions and to provide standardized thermal permafrost data to global models. In this paper we perform statistical analysis of the GTN-P metadata aiming to identify the spatial gaps in the GTN-P site distribution in relation to climate-effective environmental parameters. We describe the concept and structure of the Data Management System in regard to user operability, data transfer and data policy. We outline data sources and data processing including quality control strategies. Assessment of the metadata and data quality reveals 63% metadata completeness at active layer sites and 50% metadata completeness for boreholes. Voronoi Tessellation Analysis on the spatial sample distribution of boreholes and active layer measurement sites quantifies the distribution inhomogeneity and provides potential locations of additional permafrost research sites to improve the representativeness of thermal monitoring across areas underlain by permafrost. The depth distribution of the boreholes reveals that 73% are shallower than 25 m and 27% are deeper, reaching a maximum of 1 km depth. Comparison of the GTN-P site distribution with permafrost zones, soil organic carbon contents and vegetation types exhibits different local to regional monitoring situations on maps. Preferential slope orientation at the sites most likely causes a bias in the temperature monitoring and should be taken into account when using the data for global models. The distribution of GTN-P sites within zones of projected temperature change show a high

Airborne Surveys of Snow Depth over Arctic Sea Ice

Science.gov (United States)

Kwok, R.; Panzer, B.; Leuschen, C.; Pang, S.; Markus, T.; Holt, B.; Gogineni, S.

2011-01-01

During the spring of 2009, an ultrawideband microwave radar was deployed as part of Operation IceBridge to provide the first cross-basin surveys of snow thickness over Arctic sea ice. In this paper, we analyze data from three approx 2000 km transects to examine detection issues, the limitations of the current instrument, and the regional variability of the retrieved snow depth. Snow depth is the vertical distance between the air \\snow and snow-ice interfaces detected in the radar echograms. Under ideal conditions, the per echogram uncertainty in snow depth retrieval is approx 4 - 5 cm. The finite range resolution of the radar (approx 5 cm) and the relative amplitude of backscatter from the two interfaces limit the direct retrieval of snow depths much below approx 8 cm. Well-defined interfaces are observed over only relatively smooth surfaces within the radar footprint of approx 6.5 m. Sampling is thus restricted to undeformed, level ice. In early April, mean snow depths are 28.5 +/- 16.6 cm and 41.0 +/- 22.2 cm over first-year and multiyear sea ice (MYI), respectively. Regionally, snow thickness is thinner and quite uniform over the large expanse of seasonal ice in the Beaufort Sea, and gets progressively thicker toward the MYI cover north of Ellesmere Island, Greenland, and the Fram Strait. Snow depth over MYI is comparable to that reported in the climatology by Warren et al. Ongoing improvements to the radar system and the utility of these snow depth measurements are discussed.

Investigation on the behavioral difference in third order nonlinearity and optical limiting of Mn0.55Cu0.45Fe2O4 nanoparticles annealed at different temperatures

Science.gov (United States)

Yuvaraj, S.; Manikandan, N.; Vinitha, G.

2017-11-01

Mn0.55Cu0.45Fe2O4 nanoparticles were synthesized by wet chemical co-precipitation method. The obtained samples were annealed at different temperatures (500 °C to 1250 °C). All annealed samples were characterized for their structural, magnetic, linear and non-linear optical properties. XRD results confirm single phase cubic spinel structure only for samples annealed at 800 °C and 1250 °C. The average crystallite sizes of the samples are in the range of 11-37 nm. HR-SEM image of the sample annealed at 800 °C exposed spherical morphology. The quantitative analysis of EDX results is close to the expected values. Bandgaps were evaluated from UV-DRS. The FTIR spectrum showing the essential peaks around 452.1 and 567.2 cm-1 prove the formation of spinel nanoparticles. In PL spectrum, a broad emission peak is attained in visible region at 485 nm. The saturation magnetization (M s), coercivity (H c) and remanence magnetization (M r) are obtained from the hysteresis curve. Nonlinear absorption coefficients (10-4 cm W-1), nonlinear indices of refraction (10-8 cm2 W-1) and the third order nonlinear susceptibilities (10-6 esu) are determined using Z-scan experiment. CW laser beam is utilized to study the optical limiting characteristics and the results prove these materials to be a potential candidate for device applications like optical switches and power limiters.

Muon-spin-rotation studies of the temperature dependence of the magnetic penetration depth in the YBa2Cu3Ox family and related compounds

International Nuclear Information System (INIS)

Zimmermann, P.; Keller, H.; Lee, S.L.; Savic, I.M.; Warden, M.; Zech, D.; Cubitt, R.; Forgan, E.M.; Kaldis, E.; Karpinski, J.; Krueger, C.

1995-01-01

A systematic muon-spin-rotation (μ + SR) study is presented of the temperature dependence of the London penetration depth in sintered powder samples of the YBa 2 Cu 3 O x system and related compounds. The in-plane penetration depth λ ab is estimated from the μ + SR depolarization rate of Bi 2 Sr 2 CaCu 2 O 8+δ , YBa 2 Cu 4 O 8 , and a series of samples of the YBa 2 Cu 3 O x family, respectively. It is found that not only the low-temperature value λ ab (0), but also the temperature behavior λ ab (T) is specific to each compound. The form of λ ab (T) can be well characterized by a simple power law. In particular, the YBa 2 Cu 3 O x family shows a systematic variation of the form of λ ab (T) with the oxygen content x which points to a varying coupling strength, whereas λ ab (0) as a function of x suggests a positive charge transfer into the CuO 2 planes with increasing oxygen doping. Furthermore, our data is consistent with an empirical ansatz which has been proposed in the framework of a Bose-gas picture of high-temperature superconductivity. As a consequence, the pressure and the isotope coefficients can be extracted from the μ + SR depolarization rate and compared to direct measurements of these quantities, showing good agreement. Moreover, in the Bose-gas picture the variation of λ ab (T) in the YBa 2 Cu 3 O x family may be interpreted as a crossover from a dense (high-T c ) to a dilute (low-T c ) system of weakly interacting local pairs

Scanning Auger microscopy for high lateral and depth elemental sensitivity

Energy Technology Data Exchange (ETDEWEB)

Martinez, E., E-mail: eugenie.martinez@cea.fr [CEA, LETI, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Yadav, P. [CEA, LETI, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Bouttemy, M. [Institut Lavoisier de Versailles, 45 av. des Etats-Unis, 78035 Versailles Cedex (France); Renault, O.; Borowik, Ł.; Bertin, F. [CEA, LETI, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Etcheberry, A. [Institut Lavoisier de Versailles, 45 av. des Etats-Unis, 78035 Versailles Cedex (France); Chabli, A. [CEA, LETI, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France)

2013-12-15

Highlights: •SAM performances and limitations are illustrated on real practical cases such as the analysis of nanowires and nanodots. •High spatial elemental resolution is shown with the analysis of reference semiconducting Al{sub 0.7}Ga{sub 0.3}As/GaAs multilayers. •High in-depth elemental resolution is also illustrated. Auger depth profiling with low energy ion beams allows revealing ultra-thin layers (∼1 nm). •Analysis of cross-sectional samples is another effective approach to obtain in-depth elemental information. -- Abstract: Scanning Auger microscopy is currently gaining interest for investigating nanostructures or thin multilayers stacks developed for nanotechnologies. New generation Auger nanoprobes combine high lateral (∼10 nm), energy (0.1%) and depth (∼2 nm) resolutions thus offering the possibility to analyze the elemental composition as well as the chemical state, at the nanometre scale. We report here on the performances and limitations on practical examples from nanotechnology research. The spatial elemental sensitivity is illustrated with the analysis of Al{sub 0.7}Ga{sub 0.3}As/GaAs heterostructures, Si nanowires and SiC nanodots. Regarding the elemental in-depth composition, two effective approaches are presented: low energy depth profiling to reveal ultra-thin layers (∼1 nm) and analysis of cross-sectional samples.

Defocus Deblurring and Superresolution for Time-of-Flight Depth Cameras

KAUST Repository

Xiao, Lei

2015-06-07

Continuous-wave time-of-flight (ToF) cameras show great promise as low-cost depth image sensors in mobile applications. However, they also suffer from several challenges, including limited illumination intensity, which mandates the use of large numerical aperture lenses, and thus results in a shallow depth of field, making it difficult to capture scenes with large variations in depth. Another shortcoming is the limited spatial resolution of currently available ToF sensors. In this paper we analyze the image formation model for blurred ToF images. By directly working with raw sensor measurements but regularizing the recovered depth and amplitude images, we are able to simultaneously deblur and super-resolve the output of ToF cameras. Our method outperforms existing methods on both synthetic and real datasets. In the future our algorithm should extend easily to cameras that do not follow the cosine model of continuous-wave sensors, as well as to multi-frequency or multi-phase imaging employed in more recent ToF cameras.

Defocus Deblurring and Superresolution for Time-of-Flight Depth Cameras

KAUST Repository

Xiao, Lei; Heide, Felix; O'Toole, Matthew; Kolb, Andreas; Hullin, Matthias B.; Kutulakos, Kyros; Heidrich, Wolfgang

2015-01-01

Continuous-wave time-of-flight (ToF) cameras show great promise as low-cost depth image sensors in mobile applications. However, they also suffer from several challenges, including limited illumination intensity, which mandates the use of large numerical aperture lenses, and thus results in a shallow depth of field, making it difficult to capture scenes with large variations in depth. Another shortcoming is the limited spatial resolution of currently available ToF sensors. In this paper we analyze the image formation model for blurred ToF images. By directly working with raw sensor measurements but regularizing the recovered depth and amplitude images, we are able to simultaneously deblur and super-resolve the output of ToF cameras. Our method outperforms existing methods on both synthetic and real datasets. In the future our algorithm should extend easily to cameras that do not follow the cosine model of continuous-wave sensors, as well as to multi-frequency or multi-phase imaging employed in more recent ToF cameras.

{sup 3}He spectrum at small atmospheric depths for different geomagnetic cutoff values

Energy Technology Data Exchange (ETDEWEB)

Papini, P. [Florence Univ. (Italy)]|[INFN, Florence (Italy); Grimani, C. [Perugia Univ. (Italy)]|[INFN, Perugia (Italy); Stephens, S.A. [Tata Institute of Fundamental Research, Bombay (International Commission on Radiation Units and Measurements)

1995-09-01

It is carried out a calculation to determine the energy spectra of secondary {sup 3}He at small atmospheric depths. It is produced in the spallation reaction of primary helium and heavier nuclei in the overlying atmosphere. It is examined the effect of the geomagnetic cut-off on the spectral shape of the secondary {sup 3}He nuclei. The calculations are being carried out for both solar minimum and maximum periods. Results from these calculations will be presented at the Conference.

The recommended Threshold Limit Values for heat exposure fail to maintain body core temperature within safe limits in older working adults.

Science.gov (United States)

Lamarche, Dallon T; Meade, Robert D; D'Souza, Andrew W; Flouris, Andreas D; Hardcastle, Stephen G; Sigal, Ronald J; Boulay, Pierre; Kenny, Glen P

2017-09-01

The American Conference of Governmental and Industrial Hygienists (ACGIH®) Threshold Limit Values (TLV® guidelines) for work in the heat consist of work-rest (WR) allocations designed to ensure a stable core temperature that does not exceed 38°C. However, the TLV® guidelines have not been validated in older workers. This is an important shortcoming given that adults as young as 40 years demonstrate impairments in their ability to dissipate heat. We therefore evaluated body temperature responses in older adults during work performed in accordance to the TLV® recommended guidelines. On three occasions, 9 healthy older (58 ± 5 years) males performed a 120-min work-simulated protocol in accordance with the TLV® guidelines for moderate-to-heavy intensity work (360 W fixed rate of heat production) in different wet-bulb globe temperatures (WBGT). The first was 120 min of continuous (CON) cycling at 28.0°C WBGT (CON[28°C]). The other two protocols were 15-min intermittent work bouts performed with different WR cycles and WBGT: (i) WR of 3:1 at 29.0°C (WR3:1[29°C]) and (ii) WR of 1:1 at 30.0°C (WR1:1[30°C]). Rectal temperature was measured continuously. The rate of change in mean body temperature was determined via thermometry (weighting coefficients: rectal, 0.9; mean skin temperature, 0.1) and direct calorimetry. Rectal temperature exceeded 38°C in all participants in CON[28°C] and WR3:1[29°C] whereas a statistically similar proportion of workers exceeded 38°C in WR1:1[30°C] (χ 2 ; P = 0.32). The average time for rectal temperature to reach 38°C was: CON[28°C], 53 ± 7; WR3:1[29°C], 79 ± 11; and WR1:1[30°C], 100 ± 29 min. Finally, while a stable mean body temperature was not achieved in any work condition as measured by thermometry (i.e., >0°C·min -1 ; all Pheat balance as determined by direct calorimetry was achieved in WR3:1[29°C] and WR1:1[30°C] (both P ≥ 0.08). Our findings indicate that the TLV® guidelines do not prevent body core

London penetration depth and thermal fluctuations in the sulphur hydride 203 K superconductor

Energy Technology Data Exchange (ETDEWEB)

Talantsev, E.F.; Crump, W.P. [Robinson Research Institute, Victoria University of Wellington, Lower Hutt (New Zealand); Storey, J.G.; Tallon, J.L. [Robinson Research Institute, Victoria University of Wellington, Lower Hutt (New Zealand); MacDiarmid Institute for Advanced Materials and Nanotechnology, Lower Hutt (New Zealand)

2017-03-15

Recently, compressed H{sub 2}S has been shown to become superconducting at 203 K under a pressure of 155 GPa. One might expect fluctuations to dominate at such temperatures. Using the magnetisation critical current, we determine the ground-state London penetration depth, λ{sub 0} = 189 nm, and the superconducting energy gap, Δ{sub 0} = 27.8 meV, and find these parameters are similar to those of cuprate superconductors. We also determine the fluctuation temperature scale, T{sub fluc} = 1470 K, which shows that, unlike the cuprates, T{sub c} of the hydride is not limited by fluctuations. This is due to its three dimensionality and suggests the search for better superconductors should refocus on three-dimensional systems where the inevitable thermal fluctuations are less likely to reduce the observed T{sub c}. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Using soft-X-ray energy spectrum to measure electronic temperature Te and primary research with computer data processing

International Nuclear Information System (INIS)

Wang Jingyao; Zhang Guangyang

1993-01-01

The authors reported the application of SCORPIO--2000 Computer detecting system on a nuclear fusion equipment, to measure the energy spectrum of soft X-ray from which the plasma electronic temperature was calculated. The authors processed systematically the data of the energy area of 1-4 Kev soft X-ray. The program edited was mostly made in FORTRAN, but only one SUBSB was made in assembly language. The program worked normally with convincing operation and easy correction of the data. The result obtained from calculation is the same as what was expected and the diagram obtained is the same as the expected one

A laboratory validation study of comfort and limit temperatures of four sleeping bags defined according to EN 13537 (2002).

Science.gov (United States)

Lin, Li-Yen; Wang, Faming; Kuklane, Kalev; Gao, Chuansi; Holmér, Ingvar; Zhao, Mengmeng

2013-03-01

In this study, we validated comfort and limit temperatures of four sleeping bags with different levels of insulation defined according to EN 13537. Six male subjects and four female subjects underwent totally 20 two-hour exposures in four sleeping bags at four intended testing temperatures: 11.2, 3.8, 2.1 and -9.0 °C. The subjective perceptions and physiological responses of these subjects were reported and analyzed. It was found that the EN 13537 defined comfort temperature and limit temperature were underestimated for sleeping bags MA3, HAG and MAM. The predictions are so conservative that further revision may be required to meet the requirements of both manufacturers and consumers. In contrast, for the sleeping bag MA0 with a low level of insulation, the limit temperature defined by EN 13537 was slightly overestimated. In addition, two individual case studies (-28.0 and -32.0 °C) demonstrated that low toe temperatures were widely observed among the male and female subjects, although the mean skin temperatures were almost within the thermoneutrality range (32.0-34.0 °C). It seems that the IREQ model (ISO 11079) overestimated both the comfort and limit temperatures of the sleeping bags. Finally, traditional sleeping bags may be required to be re-designed to provide consumers both whole body comfort as well as local thermal comfort at feet/toes or users need to be made aware of the higher need for their insulation. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

BAROMETRIC PRESSURE and Other Data from NOAA Ship DISCOVERER and Other Platforms From NW Pacific (limit-180) and Others from 1992-03-03 to 1992-09-06 (NODC Accession 9400094)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Conductivity, Temperature and Depth (CTD) and other data were collected in NE Pacific (limit-180), NW Pacific (limit-180), and TOGA Area - Pacific (30 N to 30 S)...

Temperature profile and water depth data collected from SAXON STAR and other platforms in a World wide distribution from 09 March 1983 to 12 November 1986 (NODC Accession 8700035)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT from the SAXON STAR and other platforms in a World wide distribution. Data were collected...

Thermal-spectrum recriticality energetics

International Nuclear Information System (INIS)

Schwinkendorf, K.N.

1993-12-01

Large computer codes have been created in the past to predict the energy release in hypothetical core disruptive accidents (CDA), postulated to occur in liquid metal reactors (LMR). These codes, such as SIMMER, are highly specific to LMR designs. More recent attention has focused on thermal-spectrum criticality accidents, such as for fuel storage basins and waste tanks containing fissile material. This paper resents results from recent one-dimensional kinetics simulations, performed for a recriticality accident in a thermal spectrum. Reactivity insertion rates generally are smaller than in LMR CDAs, and the energetics generally are more benign. Parametric variation of input was performed, including reactivity insertion and initial temperature

Classification of Effective Soil Depth by Using Multinomial Logistic Regression Analysis

Science.gov (United States)

Chang, C. H.; Chan, H. C.; Chen, B. A.

2016-12-01

Classification of effective soil depth is a task of determining the slopeland utilizable limitation in Taiwan. The "Slopeland Conservation and Utilization Act" categorizes the slopeland into agriculture and husbandry land, land suitable for forestry and land for enhanced conservation according to the factors including average slope, effective soil depth, soil erosion and parental rock. However, sit investigation of the effective soil depth requires a cost-effective field work. This research aimed to classify the effective soil depth by using multinomial logistic regression with the environmental factors. The Wen-Shui Watershed located at the central Taiwan was selected as the study areas. The analysis of multinomial logistic regression is performed by the assistance of a Geographic Information Systems (GIS). The effective soil depth was categorized into four levels including deeper, deep, shallow and shallower. The environmental factors of slope, aspect, digital elevation model (DEM), curvature and normalized difference vegetation index (NDVI) were selected for classifying the soil depth. An Error Matrix was then used to assess the model accuracy. The results showed an overall accuracy of 75%. At the end, a map of effective soil depth was produced to help planners and decision makers in determining the slopeland utilizable limitation in the study areas.

Approximate relationship between frequency-dependent skin depth resolved from geoelectromagnetic pedotransfer function and depth of investigation resolved from geoelectrical measurements: A case study of coastal formation, southern Nigeria

Science.gov (United States)

George, N. J.; Obiora, D. N.; Ekanem, A. M.; Akpan, A. E.

2016-10-01

The task involved in the interpretation of Vertical Electrical Sounding (VES) data is how to get unique results in the absence/limited number of borehole information, which is usually limited to information on the spot. Geological and geochemical mapping of electrical properties are usually limited to direct observations on the surface and therefore, conclusions and extrapolations that can be drawn about the system electrical characteristics and possible underlying structures may be masked as geology changes with positions. The electrical resistivity study pedotransfer functions (PTFs) have been linked with the electromagnetic (EM) resolved PTFs at chosen frequencies of skin/penetration depth corresponding to the VES resolved investigation depth in order to determine the local geological attributes of hydrogeological repository in the coastal formation dominated with fine sand. The illustrative application of effective skin depth depicts that effective skin depth has direct relation with the EM response of the local source over the layered earth and thus, can be linked to the direct current earth response functions as an aid for estimating the optimum depth and electrical parameters through comparative analysis. Though the VES and EM resolved depths of investigation at appropriate effective and theoretical frequencies have wide gaps, diagnostic relations characterising the subsurface depth of interest have been established. The determining factors of skin effect have been found to include frequency/period, resistivity/conductivity, absorption/attenuation coefficient and energy loss factor. The novel diagnostic relations and their corresponding constants between 1-D resistivity data and EM skin depth are robust PTFs necessary for checking the accuracy associated with the non-unique interpretations that characterise the 1-D resistivity data, mostly when lithostratigraphic data are not available.

A probabilistic method for determining effluent temperature limits for flow instability for SRS reactors

International Nuclear Information System (INIS)

Hardy, B.J.; White, A.M.

1990-06-01

This manual describes the uncertainty analysis used to determine the effluent temperature limits for a Mark 22 charge in the Savannah River Site production reactors. The postulated accident scenario is a DEGB/LOCA resulting from a coolant pipe break at the plenum inlet accompanied by the safety rod failure described in the previous chapter. The analysis described in this manual is used to calculate the limits for the flow instability phase of the accident. For this phase of the accident, the limits criterion is that the Stanton number does not exceed 0.00455 [1]. The limits are determined for a specified 84% probability that the Stanton number will not exceed 0.00455 in any assembly in the core

A probabilistic method for determining effluent temperature limits for flow instability for SRS reactors

Energy Technology Data Exchange (ETDEWEB)

Hardy, B.J.; White, A.M.

1990-06-01

This manual describes the uncertainty analysis used to determine the effluent temperature limits for a Mark 22 charge in the Savannah River Site production reactors. The postulated accident scenario is a DEGB/LOCA resulting from a coolant pipe break at the plenum inlet accompanied by the safety rod failure described in the previous chapter. The analysis described in this manual is used to calculate the limits for the flow instability phase of the accident. For this phase of the accident, the limits criterion is that the Stanton number does not exceed 0.00455 [1]. The limits are determined for a specified 84% probability that the Stanton number will not exceed 0.00455 in any assembly in the core.

Experimental measurement of neutron spectrum in the reflector of a light water reactor

International Nuclear Information System (INIS)

Brethe, P.

1963-09-01

1. Thermal neutrons: The temperature of the thermal neutron spectrum was calculated using Au-Lu foils. This temperature varies from 300 deg. K (temperature of the moderator) at 30 cm of the core to 350 deg. K in a hole of the core. 2. Slowing down of neutron: Four resonance detectors have been used (Au, In, Co, Mn). We can write a 1/E form of the spectrum. The linking up energy E M between thermal neutron spectrum and slowing down spectrum is about 0.23 eV and is free from the Maxwell spectrum temperature. The decrease of slowing down flux regarding thermal flux, farther from the core, has been showed. 3. Fast neutrons: We used 3 threshold detectors (Ni, Al, Mg). We supposed a E 1/2 e -βE from of the spectrum above 3 MeV. The values of β are in a range from 0.775, at the centre of the core and in a loop-hole, to 0,64 at about 30 cm of the core. 4. Continuous shape of the spectrum: The following interpolations give useful informations between the field where measurements have been made: between 340 eV and 10 keV: 1/E form between 10 keV and 330 keV: 1/(E σ S (E)) form (σ S (E) elastic scattering section on hydrogen) between 330 keV and 3 MeV: calculated form by the moments method (ref. BSR). (author) [fr

DS86 neutron dose. Monte Carlo analysis for depth profile of {sup 152}Eu activity in a large stone sample

Energy Technology Data Exchange (ETDEWEB)

Endo, Satoru; Hoshi, Masaharu; Takada, Jun [Hiroshima Univ. (Japan). Research Inst. for Radiation Biology and Medicine; Iwatani, Kazuo; Oka, Takamitsu; Shizuma, Kiyoshi; Imanaka, Tetsuji; Fujita, Shoichiro; Hasai, Hiromi

1999-06-01

The depth profile of {sup 152}Eu activity induced in a large granite stone pillar by Hiroshima atomic bomb neutrons was calculated by a Monte Carlo N-Particle Transport Code (MCNP). The pillar was on the Motoyasu Bridge, located at a distance of 132 m (WSW) from the hypocenter. It was a square column with a horizontal sectional size of 82.5 cm x 82.5 cm and height of 179 cm. Twenty-one cells from the north to south surface at the central height of the column were specified for the calculation and {sup 152}Eu activities for each cell were calculated. The incident neutron spectrum was assumed to be the angular fluence data of the Dosimetry System 1986 (DS86). The angular dependence of the spectrum was taken into account by dividing the whole solid angle into twenty-six directions. The calculated depth profile of specific activity did not agree with the measured profile. A discrepancy was found in the absolute values at each depth with a mean multiplication factor of 0.58 and also in the shape of the relative profile. The results indicated that a reassessment of the neutron energy spectrum in DS86 is required for correct dose estimation. (author)

Line broadening mechanisms of the orth-H2 pair spectrum

International Nuclear Information System (INIS)

Statt, B.W.; Hardy, W.N.

1980-01-01

Three broadening mechanisms for the ortho pair spectrum in solid hydrogen are investigated. First, theoretical predictions of the phonon induced lifetime broadening are presented. Next a theory is developed which gives the inhomogeneous broadening due to the presence of ortho molecules surrounding the pairs. An unexpected result is that certain lines remain unbroadened, at least to within the approximation made. Strain effects due to isotopic mass defect impurities are also considered. These predictions are then compared with experimental results. No temperature dependence of the lineshapes is observed, setting an upper limit on the phonon broadening contribution to the linewidth. This limit is an order of magnitude lower than the theory predicts. The predictions of the ortho broadening theory, on the other hand, are in good agreement with experiment. Samples doped with isotopic impurities are also investigated. (auth)

The cosmic ray muon spectrum and charge ratio in CosmoALEPH

CERN Document Server

Zimmermann, D; Kotaidis, V; Luitz, S; Mailov, A; Müller, A S; Putzer, A; Rensch, B; Sander, H G; Schmeling, S; Schmelling, M; Wachsmuth, H W; Tcaciuc, R; Ziegler, T; Zuber, K

2004-01-01

The ALEPH experiment at the LEP e**+e**- storage ring at CERN has been used to measure the momentum spectrum of cosmic ray muons. ALEPH is located at a vertical depth of 320 m.w.e. underground close to the Jura mountains. The high resolution of the time projection chamber (TPC) of ALEPH allows to reconstruct muon tracks with momenta up to the TeV region. The measured muon momentum spectrum and the charge ratio in the range from 80 to 2500 GeV are presented. After corrections for energy loss in the overburden the sea level muon spectrum at nearly vertical incidence is obtained. The experimental data are compared to theoretical expectations and results from other experiments.

Secondary proton production at small atmospheric depths as a function of the geomagnetic cut-off

Energy Technology Data Exchange (ETDEWEB)

Papini, P. [Florence Univ. (Italy)]|[INFN, Florence (Italy); Grimani, C. [Perugia Univ. (Italy)]|[INFN, Perugia (Italy); Stephens, S.A. [Tata Institute of Fundamental Research, Bombay (International Commission on Radiation Units and Measurements)

1995-09-01

A detailed calculation of the energy spectrum of secondary protons in the atmosphere is being carried out in the energy range 20 MeV - 40 GeV. In this calculation, it is taken into account all processes leading to the production of secondary protons as a function of the atmospheric depth has been calculated using all relevant energy loss processes. In this paper, it is examine the effect of the geomagnetic cut-off on the spectral shape of secondary protons specially at energies below the geomagnetic cut-off for small atmospheric depths.

Secondary proton production at small atmospheric depths as a function of the geomagnetic cut-off

International Nuclear Information System (INIS)

Papini, P.; Grimani, C.; Stephens, S.A.

1995-01-01

A detailed calculation of the energy spectrum of secondary protons in the atmosphere is being carried out in the energy range 20 MeV - 40 GeV. In this calculation, it is taken into account all processes leading to the production of secondary protons as a function of the atmospheric depth has been calculated using all relevant energy loss processes. In this paper, it is examine the effect of the geomagnetic cut-off on the spectral shape of secondary protons specially at energies below the geomagnetic cut-off for small atmospheric depths

Method to estimate the effective temperatures of late-type giants using line-depth ratios in the wavelength range 0.97-1.32 μm

Science.gov (United States)

Taniguchi, Daisuke; Matsunaga, Noriyuki; Kobayashi, Naoto; Fukue, Kei; Hamano, Satoshi; Ikeda, Yuji; Kawakita, Hideyo; Kondo, Sohei; Sameshima, Hiroaki; Yasui, Chikako

2018-02-01

The effective temperature, one of the most fundamental atmospheric parameters of a star, can be estimated using various methods; here, we focus on a method using line-depth ratios (LDRs). This method combines low- and high-excitation lines and makes use of relations between LDRs of these line pairs and the effective temperature. It has an advantage, for example, of being minimally affected by interstellar reddening, which changes stellar colours. We report 81 relations between LDRs and effective temperature established with high-resolution, λ/Δλ ∼ 28 000, spectra of nine G- to M-type giants in the Y and J bands. Our analysis gives the first comprehensive set of LDR relations for this wavelength range. The combination of all these relations can be used to determine the effective temperatures of stars that have 3700 < Teff < 5400 K and -0.5 < [Fe/H] < +0.3 dex, to a precision of ±10 K in the best cases.

Dragon kings of the deep sea: marine particles deviate markedly from the common number-size spectrum

NARCIS (Netherlands)

Bochdansky, A.B.; Clouse, M.A.; Herndl, G.

2016-01-01

Particles are the major vector for the transfer of carbon from the upper ocean to the deep sea. However, little is known about their abundance, composition and role at depths greater than 2000?m. We present the first number-size spectrum of bathy- and abyssopelagic particles to a depth of 5500?m

Stream water temperature limits occupancy of salamanders in mid-Atlantic protected areas

Science.gov (United States)

Grant, Evan H. Campbell; Wiewel, Amber N. M.; Rice, Karen C.

2014-01-01

Stream ecosystems are particularly sensitive to urbanization, and tolerance of water-quality parameters is likely important to population persistence of stream salamanders. Forecasted climate and landscape changes may lead to significant changes in stream flow, chemical composition, and temperatures in coming decades. Protected areas where landscape alterations are minimized will therefore become increasingly important for salamander populations. We surveyed 29 streams at three national parks in the highly urbanized greater metropolitan area of Washington, DC. We investigated relationships among water-quality variables and occupancy of three species of stream salamanders (Desmognathus fuscus, Eurycea bislineata, and Pseudotriton ruber). With the use of a set of site-occupancy models, and accounting for imperfect detection, we found that stream-water temperature limits salamander occupancy. There was substantial uncertainty about the effects of the other water-quality variables, although both specific conductance (SC) and pH were included in competitive models. Our estimates of occupancy suggest that temperature, SC, and pH have some importance in structuring stream salamander distribution.

Intercomparison On Depth Dose Measurement

International Nuclear Information System (INIS)

Rohmah, N; Akhadi, M

1996-01-01

Intercomparation on personal dose evaluation system has been carried out between CSRSR-NAEA of Indonesia toward Standard Laboratory of JAERI (Japan) and ARL (Australia). The intercomparison was in 10 amm depth dose measurement , Hp (10), from the intercomparison result could be stated that personal depth dose measurement conducted by CSRSR was sufficiently good. Deviation of dose measurement result using personal dosemeter of TLD BG-1 type which were used by CSRSR in the intercomparison and routine photon personal dose monitoring was still in internationally agreed limit. Maximum deviation of reported doses by CSRSR compared to delivered doses for dosemeter irradiation by JAERI was -10.0 percent and by ARL was +29 percent. Maximum deviation permitted in personal dose monitoring is ± 50 percent

Measuring soil frost depth in forest ecosystems with ground penetrating radar

Science.gov (United States)

John R. Butnor; John L. Campbell; James B. Shanley; Stanley. Zarnoch

2014-01-01

Soil frost depth in forest ecosystems can be variable and depends largely on early winter air temperatures and the amount and timing of snowfall. A thorough evaluation of ecological responses to seasonally frozen ground is hampered by our inability to adequately characterize the frequency, depth, duration and intensity of soil frost events. We evaluated the use of...

Oregon Low-Temperature-Resource Assessment Program. Final technical report

Energy Technology Data Exchange (ETDEWEB)

Priest, G.R.; Black, G.L.; Woller, N.M.

1981-01-01

Numerous low-temperature hydrothermal systems are available for exploitation throughout the Cascades and eastern Oregon. All of these areas have heat flow significantly higher than crustal averages and many thermal aquifers. In northeastern Oregon, low temperature geothermal resources are controlled by regional stratigraphic aquifers of the Columbia River Basalt Group at shallow depths and possibly by faults at greater depths. In southeastern Oregon most hydrothermal systems are of higher temperature than those of northeastern Oregon and are controlled by high-angle fault zones and layered volcanic aquifers. The Cascades have very high heat flow but few large population centers. Direct use potential in the Cascades is therefore limited, except possibly in the cities of Oakridge and Ashland, where load may be great enough to stimulate development. Absence of large population centers also inhibits initial low temperature geothermal development in eastern Oregon. It may be that uses for the abundant low temperature geothermal resources of the state will have to be found which do not require large nearby population centers. One promising use is generation of electricity from freon-based biphase electrical generators. These generators will be installed on wells at Vale and Lakeview in the summer of 1982 to evaluate their potential use on geothermal waters with temperatures as low as 80/sup 0/C (176/sup 0/F).

Vibrational spectrum of the K-590 intermediate in the bacteriorhodopsin photocycle at room temperature: picosecond time-resolved resonance coherent anti-Raman spectroscopy

Science.gov (United States)

Ujj, L.; Jäger, F.; Popp, A.; Atkinson, G. H.

1996-12-01

The vibrational spectrum of the K-590 intermediate, thought to contribute significantly to the energy storage and transduction mechanism in the bacteriorhodopsin (BR) photocycle, is measured at room temperature using picosecond time-resolved resonance coherent anti-Stokes Raman scattering (PTR/CARS). The room-temperature BR photocycle is initiated by the 3 ps, 570 nm excitation of the ground-state species, BR-570, prepared in both H 2O and D 2O suspensions of BR. PTR/CARS data, recorded 50 ps after BR-570 excitation, at which time only BR-570 and K-590 are present, have an excellent S/N which provides a significantly more detailed view of the K-590 vibrational degrees of freedom than previously available. Two picosecond (6 ps FWHM) laser pulses, ω1 (633.4 nm) and ωS (675-700 nm), are used to record PTR/CARS data via electronic resonance enhancement in both BR-570 and K-590, each of which contains a distinct retinal structure (assigned as 13- rans, 15- anti, 13- cis, respectively). To obtain the vibrational spectrum of K-590 separately, the PTR/CARS spectra from the mixture of isomeric retinals is quantitatively analyzed in terms of third-order susceptibility ( η(3)) relationships. PTR/CARS spectra of K-590 recorded from both H 2O and D 2O suspensions of BR are compared with the analogous vibrational data obtained via spontaneous resonance Raman (RR) scattering at both low (77 K) and room temperature. Analyses of these vibrational spectra identify temperature-dependent effects and changes assignable to the substitution of deuterium at the Schiff-base nitrogen not previously reported.

Performance of an irreversible quantum Ericsson cooler at low temperature limit

International Nuclear Information System (INIS)

Wu Feng; Chen Lingen; Wu Shuang; Sun Fengrui

2006-01-01

The purpose of this paper is to investigate the effect of quantum properties of the working medium on the performance of an irreversible quantum Ericsson cooler with spin-1/2. The cooler is studied with the losses of heat resistance, heat leakage and internal irreversibility. The optimal relationship between the dimensionless cooling load R * versus the coefficient of performance ε for the irreversible quantum Ericsson cooler is derived. In particular, the performance characteristics of the cooler at the low temperature limit are discussed

TAO/TRITON, RAMA, and PIRATA Buoys, Daily, 1977-present, 20C Isotherm Depth

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset has daily 20C Isotherm Depth data (the depth at which the ocean temperature is 20C) from the TAO/TRITON (Pacific Ocean, https://www.pmel.noaa.gov/gtmba/...

Temperature and depth dependence of positron annihilation parameters in YBa2Cu3O/sub 7-x/ and La/sub 1.85/Sr/sub 0.15/CuO4

International Nuclear Information System (INIS)

Lynn, K.G.; Usmar, S.G.; Nielsen, B.; van der Kolk, G.; Kanazawa, I.; Sferlazzo, P.; Moodenbaugh, A.R.

1988-01-01

The temperature dependence of the positron annihilation parameters for YBa 2 Cu 3 O/sub 7-//sub x/ x = 0.7, 0.4 and 0.0 and La/sub 1.85/Sr/sub 0.15/CuO 4 were measured. The depth dependence of the YBa 2 Cu 3 O 7 was studied using a variable-energy positron beam showing a strong depth dependence in the Doppler line-shape extending up to an average depth of ∼5.0 μm. It was found that a transition in the Doppler line-shape parameter, ''S'', was associated with the superconducting transition temperature (T/sub c/) in YBa 2 Cu 3 O/sub 7-x/ x = 0.4 and 0.0 while no transition was observed in the nonsuperconducting YBa 2 Cu 3 O/sub 6.3/. Positron lifetime parameters in YBa 2 Cu 3 O 7 were found to be consistent with positrons localized at open volume regions (probably unoccupied crystallographic sites) in this material with a lifetime of 210 psec at 300 K. These results indicate that the electron density at these unoccupied sites increases, using a free electron model, approximately 9% between 100 and 12 K

Evaluate depth of field limits of fixed focus lens arrangements in thermal infrared

Science.gov (United States)

Schuster, Norbert

2016-05-01

More and more modern thermal imaging systems use uncooled detectors. High volume applications work with detectors that have a reduced pixel count (typically between 200x150 and 640x480). This reduces the usefulness of modern image treatment procedures such as wave front coding. On the other hand, uncooled detectors demand lenses with fast fnumbers, near f/1.0, which reduces the expected Depth of Field (DoF). What are the limits on resolution if the target changes distance to the camera system? The desire to implement lens arrangements without a focusing mechanism demands a deeper quantification of the DoF problem. A new approach avoids the classic "accepted image blur circle" and quantifies the expected DoF by the Through Focus MTF of the lens. This function is defined for a certain spatial frequency that provides a straightforward relation to the pixel pitch of imaging device. A certain minimum MTF-level is necessary so that the complete thermal imaging system can realize its basic functions, such as recognition or detection of specified targets. Very often, this technical tradeoff is approved with a certain lens. But what is the impact of changing the lens for one with a different focal length? Narrow field lenses, which give more details of targets in longer distances, tighten the DoF problem. A first orientation is given by the hyperfocal distance. It depends in a square relation on the focal length and in a linear relation on the through focus MTF of the lens. The analysis of these relations shows the contradicting requirements between higher thermal and spatial resolution, faster f-number and desired DoF. Furthermore, the hyperfocal distance defines the DoF-borders. Their relation between is such as the first order imaging formulas. A calculation methodology will be presented to transfer DoF-results from an approved combination lens and camera to another lens in combination with the initial camera. Necessary input for this prediction is the accepted DoF of

THE FLAT TRANSMISSION SPECTRUM OF THE SUPER-EARTH GJ1214b FROM WIDE FIELD CAMERA 3 ON THE HUBBLE SPACE TELESCOPE

International Nuclear Information System (INIS)

Berta, Zachory K.; Charbonneau, David; Désert, Jean-Michel; Irwin, Jonathan; Miller-Ricci Kempton, Eliza; Fortney, Jonathan J.; Nutzman, Philip; McCullough, Peter R.; Burke, Christopher J.; Homeier, Derek

2012-01-01

Capitalizing on the observational advantage offered by its tiny M dwarf host, we present Hubble Space Telescope/Wide Field Camera 3 (WFC3) grism measurements of the transmission spectrum of the super-Earth exoplanet GJ1214b. These are the first published WFC3 observations of a transiting exoplanet atmosphere. After correcting for a ramp-like instrumental systematic, we achieve nearly photon-limited precision in these observations, finding the transmission spectrum of GJ1214b to be flat between 1.1 and 1.7 μm. Inconsistent with a cloud-free solar composition atmosphere at 8.2σ, the measured achromatic transit depth most likely implies a large mean molecular weight for GJ1214b's outer envelope. A dense atmosphere rules out bulk compositions for GJ1214b that explain its large radius by the presence of a very low density gas layer surrounding the planet. High-altitude clouds can alternatively explain the flat transmission spectrum, but they would need to be optically thick up to 10 mbar or consist of particles with a range of sizes approaching 1 μm in diameter.

Dijet invariant mass spectrum at CDF

International Nuclear Information System (INIS)

Incagli, M.

1992-11-01

A summary of QCD results obtained using the dijet invariant mass spectrum dσ/dM jj is presented. The spectrum is compared with QCD Leader Order and with the recently published Next to Leading Order calculations. A limit on the scale of an eventual quark compositness can be set at Λ=1300 GeV. Limits on the production of new particles, decaying hadronically, are presented, too. Axigluons are ruled out in the mass range [240, 640] GeV, for a theory with N=10 strong interacting fermions, and in the two windows [260, 280] GeV and [450, 550] GeV, for N=20

Magnitude, precision, and realism of depth perception in stereoscopic vision.

Science.gov (United States)

Hibbard, Paul B; Haines, Alice E; Hornsey, Rebecca L

2017-01-01

Our perception of depth is substantially enhanced by the fact that we have binocular vision. This provides us with more precise and accurate estimates of depth and an improved qualitative appreciation of the three-dimensional (3D) shapes and positions of objects. We assessed the link between these quantitative and qualitative aspects of 3D vision. Specifically, we wished to determine whether the realism of apparent depth from binocular cues is associated with the magnitude or precision of perceived depth and the degree of binocular fusion. We presented participants with stereograms containing randomly positioned circles and measured how the magnitude, realism, and precision of depth perception varied with the size of the disparities presented. We found that as the size of the disparity increased, the magnitude of perceived depth increased, while the precision with which observers could make depth discrimination judgments decreased. Beyond an initial increase, depth realism decreased with increasing disparity magnitude. This decrease occurred well below the disparity limit required to ensure comfortable viewing.

Factors controlling contrail cirrus optical depth

Directory of Open Access Journals (Sweden)

B. Kärcher

2009-08-01

Full Text Available Aircraft contrails develop into contrail cirrus by depositional growth and sedimentation of ice particles and horizontal spreading due to wind shear. Factors controlling this development include temperature, ice supersaturation, thickness of ice-supersaturated layers, and vertical gradients in the horizontal wind field. An analytical microphysical cloud model is presented and validated that captures these processes. Many individual contrail cirrus are simulated that develop differently owing to the variability in the controlling factors, resulting in large samples of cloud properties that are statistically analyzed. Contrail cirrus development is studied over the first four hours past formation, similar to the ages of line-shaped contrails that were tracked in satellite imagery on regional scales. On these time scales, contrail cirrus optical depth and microphysical variables exhibit a marked variability, expressed in terms of broad and skewed probability distribution functions. Simulated mean optical depths at a wavelength of 0.55 μm range from 0.05-0.5 and a substantial fraction 20-50% of contrail cirrus stay subvisible (optical depth <0.02, depending on meteorological conditions.

A detailed analysis based on an observational case study over the continental USA suggests that previous satellite measurements of line-shaped persistent contrails have missed about 89%, 50%, and 11% of contrails with optical depths 0-0.05, 0.05-0.1, and 0.1-0.2, respectively, amounting to 65% of contrail coverage of all optical depths. When comparing observations with simulations and when estimating the contrail cirrus climate impact, not only mean values but also the variability in optical depth and microphysical properties need to be considered.

Burn Depth Estimation Using Thermal Excitation and Imaging

Energy Technology Data Exchange (ETDEWEB)

Dickey, F.M.; Holswade, S.C.; Yee, M.L.

1998-12-17

Accurate estimation of the depth of partial-thickness burns and the early prediction of a need for surgical intervention are difficult. A non-invasive technique utilizing the difference in thermal relaxation time between burned and normal skin may be useful in this regard. In practice, a thermal camera would record the skin's response to heating or cooling by a small amount-roughly 5{degrees} Celsius for a short duration. The thermal stimulus would be provided by a heat lamp, hot or cold air, or other means. Processing of the thermal transients would reveal areas that returned to equilibrium at different rates, which should correspond to different burn depths. In deeper thickness burns, the outside layer of skin is further removed from the constant-temperature region maintained through blood flow. Deeper thickness areas should thus return to equilibrium more slowly than other areas. Since the technique only records changes in the skin's temperature, it is not sensitive to room temperature, the burn's location, or the state of the patient. Preliminary results are presented for analysis of a simulated burn, formed by applying a patch of biosynthetic wound dressing on top of normal skin tissue.

THE ATACAMA COSMOLOGY TELESCOPE: A MEASUREMENT OF THE PRIMORDIAL POWER SPECTRUM

Energy Technology Data Exchange (ETDEWEB)

Hlozek, Renee; Dunkley, Joanna; Addison, Graeme [Department of Astrophysics, Oxford University, Oxford OX1 3RH (United Kingdom); Appel, John William; Das, Sudeep; Essinger-Hileman, Thomas; Fowler, Joseph W.; Hajian, Amir; Hincks, Adam D. [Joseph Henry Laboratories of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544 (United States); Bond, J. Richard [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada); Carvalho, C. Sofia [IPFN, IST, Av. RoviscoPais, 1049-001Lisboa, Portugal and RCAAM, Academy of Athens, Soranou Efessiou 4, 11-527 Athens (Greece); Devlin, Mark J.; Klein, Jeff [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Duenner, Rolando; Gallardo, Patricio [Departamento de Astronomia y Astrofisica, Facultad de Fisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Halpern, Mark; Hasselfield, Matthew [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Hilton, Matt [School of Physics and Astronomy, University of Nottingham, University Park, Nottingham, NG7 2RD (United Kingdom); Hughes, John P. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854-8019 (United States); Irwin, Kent D. [NIST Quantum Devices Group, 325 Broadway Mailcode 817.03, Boulder, CO 80305 (United States); and others

2012-04-10

We present constraints on the primordial power spectrum of adiabatic fluctuations using data from the 2008 Southern Survey of the Atacama Cosmology Telescope (ACT) in combination with measurements from the Wilkinson Microwave Anisotropy Probe and a prior on the Hubble constant. The angular resolution of ACT provides sensitivity to scales beyond l = 1000 for resolution of multiple peaks in the primordial temperature power spectrum, which enables us to probe the primordial power spectrum of adiabatic scalar perturbations with wavenumbers up to k {approx_equal} 0.2 Mpc{sup -1}. We find no evidence for deviation from power-law fluctuations over two decades in scale. Matter fluctuations inferred from the primordial temperature power spectrum evolve over cosmic time and can be used to predict the matter power spectrum at late times; we illustrate the overlap of the matter power inferred from cosmic microwave background measurements (which probe the power spectrum in the linear regime) with existing probes of galaxy clustering, cluster abundances, and weak-lensing constraints on the primordial power. This highlights the range of scales probed by current measurements of the matter power spectrum.

On the high energy gamma ray spectrum and the particle production model

International Nuclear Information System (INIS)

Ohta, Itaru; Tezuka, Ikuo.

1979-01-01

A small emulsion chamber, 25 cm x 20 cm in area and 12 radiation lengths in thick, was exposed with JAL jet-cargo at an atmospheric depth of 260 g/cm 2 during 150 hrs. The gamma ray spectrum derived by combining data from X-ray films and nuclear emulsions is well represented by I sub(r) (>=Er) = (3.65 +- 0.30) x 10 -8 [E sub(r)/TeV]sup(-1.89+0.06-0.09)/cm 2 sr sec in the energy range 200 - 3,000 GeV. This result is in good agreement with those of several other groups. We discuss our data in terms of Feynman's and Koba-Nielsen-Olesen's scaling law of high energy particle production model. Interpreted in terms of an assumption of mild violation of the scaling law as x.d delta-s / delta-s indx = AE sup(2a)exp (-BE sup(a)x), our gamma ray spectrum results suggest an existence of a violation parameter of a = 0.18, which is consistent with results from gamma ray spectrum observations at great depth such as the mountain elevations. (author)

Study on biodiesel heat transfer through self-temperature limit injector during vehicle cold start

Directory of Open Access Journals (Sweden)

Wang Jun

2015-01-01

Full Text Available A type of Self-Temperature Limit-Injector (STL- injector is proposed to reduce the biodiesel consumption and emission in vehicle cold start process. The STL-injector is capable of fast raising fuel temperature, which helps improve the quality of diesel spray and its combustion efficiency. A STL-injector model is established with consideration of electro-mechanic coupling and fluid-structure interaction. A transient simulation is conducted using dynamic grid technology. The results show that STL-injector can effectively raise biodiesel temperature to 350K from 300K in 32 seconds. That is to say, adding STL-injector to existing biodiesel combustion system is an environment-friendly solution due to improving atomization and spray quality quickly.

Using Opaque Image Blur for Real-Time Depth-of-Field Rendering

DEFF Research Database (Denmark)

Kraus, Martin

2011-01-01

While depth of field is an important cinematographic means, its use in real-time computer graphics is still limited by the computational costs that are necessary to achieve a sufficient image quality. Specifically, color bleeding artifacts between objects at different depths are most effectively...

Sulcus depth reproduction with polyvinyl siloxane impression material: effects of hydrophilicity and impression temperature.

Science.gov (United States)

Takahashi, Hidekazu; Finger, Werner J; Kurokawa, Rie; Furukawa, Masae; Komatsu, Masashi

2010-03-01

To determine the sulcus penetration ability of hydrophilic and hydrophobic polyvinyl siloxane (PVS) impression materials by impression technique, temperature, and sulcus width. Hydrophilic Flexitime (FLE; Heraeus Kulzer) and its hydrophobic counterpart (EXP) without surfactant were investigated, using light (L), monophase (M), and heavy (H) consistencies. A truncated steel cone surrounded by a 2-mm-deep and 50-, 100-, or 200-microm-wide sulcus, simulating the gingival tissue with agar, served as the test model. Impressions were made with single-mix (L or M) and double-mix (LM or LH) techniques at 23 degrees C and 37 degrees C, respectively. The reproduced sulcus heights were measured with a 3D laser scanner. Data were analyzed by ANOVA and Tukey HSD (P 1.9 mm); FLE-M, -LM, and-LH reproductions were shorter with narrow sulci. Reproductions of 50- and 100-microm sulci with EXP-L were shallower than with FLE-L. The shortest reproduction was, however, greater than 1.6 mm. In spite of some significant differences found in sulcus-reproducing ability with hydrophilic and hydrophobic impression materials applied at different impression-making temperatures and with different techniques, the practical relevance is limited.

Induction Thermography for Surface Crack Detection and Depth Determination

Directory of Open Access Journals (Sweden)

Beate Oswald-Tranta

2018-02-01

Full Text Available In the last few years, induction thermography has been established as a non-destructive testing method for localizing surface cracks in metals. The sample to be inspected is heated with a short induced electrical current pulse, and the infrared camera records—during and after the heating pulse—the temperature distribution at the surface. Transforming the temporal temperature development for each pixel to phase information makes not only highly reliable detection of the cracks possible but also allows an estimation of its depth. Finite element simulations were carried out to investigate how the phase contrast depends on parameters such as excitation frequency, pulse duration, material parameters, crack depth, and inclination angle of the crack. From these results, generalized functions for the dependency of the phase difference on all these parameters were derived. These functions can be used as an excellent guideline as to how measurement parameters should be optimized for a given material to be able to detect cracks and estimate their depth. Several experiments on different samples were also carried out, and the results compared with the simulations showed very good agreement.

Observational constraints on the primordial curvature power spectrum

Science.gov (United States)

Emami, Razieh; Smoot, George F.

2018-01-01

CMB temperature fluctuation observations provide a precise measurement of the primordial power spectrum on large scales, corresponding to wavenumbers 10‑3 Mpc‑1 lesssim k lesssim 0.1 Mpc‑1, [1-7, 11]. Luminous red galaxies and galaxy clusters probe the matter power spectrum on overlapping scales (0.02 Mpc‑1 lesssim k lesssim 0.7 Mpc‑1 [10, 12-20]), while the Lyman-alpha forest reaches slightly smaller scales (0.3 Mpc‑1 lesssim k lesssim 3 Mpc‑1 [22]). These observations indicate that the primordial power spectrum is nearly scale-invariant with an amplitude close to 2 × 10‑9, [5, 23-28]. These observations strongly support Inflation and motivate us to obtain observations and constraints reaching to smaller scales on the primordial curvature power spectrum and by implication on Inflation. We are able to obtain limits to much higher values of k lesssim 105 Mpc‑1 and with less sensitivity even higher k lesssim 1019‑ 1023 Mpc‑1 using limits from CMB spectral distortions and other limits on ultracompact minihalo objects (UCMHs) and Primordial Black Holes (PBHs). PBHs are one of the known candidates for the Dark Matter (DM). Due to their very early formation, they could give us valuable information about the primordial curvature perturbations. These are complementary to other cosmological bounds on the amplitude of the primordial fluctuations. In this paper, we revisit and collect all the published constraints on both PBHs and UCMHs. We show that unless one uses the CMB spectral distortion, PBHs give us a very relaxed bounds on the primordial curvature perturbations. UCMHs, on the other hand, are very informative over a reasonable k range (3 lesssim k lesssim 106 Mpc‑1) and lead to significant upper-bounds on the curvature spectrum. We review the conditions under which the tighter constraints on the UCMHs could imply extremely strong bounds on the fraction of DM that could be PBHs in reasonable models. Failure to satisfy these conditions would

Multiple scattering effects in depth resolution of elastic recoil detection

International Nuclear Information System (INIS)

Wielunski, L.S.; Harding, G.L.

1998-01-01

Elastic Recoil Detection (ERD) is used to profile hydrogen and other low mass elements in thin films at surface and interfaces in a similar way that Rutherford Backscattering Spectroscopy (RBS) is used to detect and profile heavy elements. It is often assumed that the depth resolutions of these two techniques are similar. However, in contrast to typical RBS, the depth resolution of ERD is limited substantially by multiple scattering. In experimental data analysis and/or spectra simulations of a typical RBS measurement multiple scattering effects are often ignored. Computer programs used in IBA, such as RUMP, HYPRA or RBX do not include multiple scattering effects at all. In this paper, using practical thin metal structures with films containing intentionally introduced hydrogen, we demonstrate experimental ERD depth resolution and sensitivity limitations. The effects of sample material and scattering angle are also discussed. (authors)

Line-depth-ratio temperatures for the close binary ν Octantis: new evidence supporting the conjectured circumstellar retrograde planet

Science.gov (United States)

Ramm, D. J.

2015-06-01

We explore the possibly that either star-spots or pulsations are the cause of a periodic radial velocity (RV) signal (P ˜ 400 d) from the K-giant binary ν Octantis (P ˜ 1050 d, e ˜ 0.25), alternatively conjectured to have a retrograde planet. Our study is based on temperatures derived from 22 line-depth ratios (LDRs) for ν Oct and 20 calibration stars. Empirical evidence and stability modelling provide unexpected support for the planet since other standard explanations (star-spots, pulsations and additional stellar masses) each have credibility problems. However, the proposed system presents formidable challenges to planet formation and stability theories: it has by far the smallest stellar separation of any claimed planet-harbouring binary (a_{_bin} ˜ 2.6 au) and an equally unbelievable separation ratio (a_{_pl}/a_{_bin} ˜ 0.5), hence the necessity that the circumstellar orbit be retrograde. The LDR analysis of 215 ν Oct spectra acquired between 2001 and 2007, from which the RV perturbation was first revealed, have no significant periodicity at any frequency. The LDRs recover the original 21 stellar temperatures with an average accuracy of 45 ± 25 K. The 215 ν Oct temperatures have a standard deviation of only 4.2 K. Assuming the host primary is not pulsating, the temperatures converted to magnitude differences strikingly mimic the very stable photometric Hipparcos observations 15 years previously, implying the long-term stability of the star and demonstrating a novel use of LDRs as a photometric gauge. Our results provide substantial new evidence that conventional star-spots and pulsations are unlikely causes of the RV perturbation. The controversial system deserves continued attention, including with higher resolving-power spectra for bisector and LDR analyses.

Temperature profile and water depth data collected from BROOKE using BT and XBT casts in the North Pacific Ocean from 03 October 1975 to 18 November 1977 (NODC Accession 8900225)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the BROOKE in the North Pacific Ocean and TOGA Area - Pacific Ocean. Data were...

Temperature profile and water depth data from BT and XBT casts in the Atlantic Ocean from USCGC POLAR SEA from 14 December 1983 to 06 May 1984 (NODC Accession 8600108)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USCGC POLAR SEA in the Atlantic Ocean. Data were collected from 14 December...

How and to what extent does precipitation on multi-temporal scales and soil moisture at different depths determine carbon flux responses in a water-limited grassland ecosystem?

Science.gov (United States)

Fang, Qingqing; Wang, Guoqiang; Xue, Baolin; Liu, Tingxi; Kiem, Anthony

2018-04-23

In water-limited ecosystems, hydrological processes significantly affect the carbon flux. The semi-arid grassland ecosystem is particularly sensitive to variations in precipitation (PRE) and soil moisture content (SMC), but to what extent is not fully understood. In this study, we estimated and analyzed how hydrological variables, especially PRE at multi-temporal scales (diurnal, monthly, phenological-related, and seasonal) and SMC at different soil depths (0-20 cm, 20-40 cm, 40-60 cm, 60-80 cm) affect the carbon flux. For these aims, eddy covariance data were combined with a Vegetation Photosynthesis and Respiration Model (VPRM) to simulate the regional gross primary productivity (GPP), ecosystem respiration (R eco ), and net ecosystem exchange of CO 2 (NEE). Interestingly, carbon flux showed no relationship with diurnal PRE or phenological-related PRE (precipitation in the growing season and non-growing season). However, carbon flux was significantly related to monthly PRE and to seasonal PRE (spring + summer, autumn). The GPP, R eco , and NEE increased in spring and summer but decreased in autumn with increasing precipitation due to the combined effect of salinization in autumn. The GPP, R eco , and NEE were more responsive to SMC at 0-20 cm depth than at deeper depths due to the shorter roots of herbaceous vegetation. The NEE increased with increasing monthly PRE because soil microbes responded more quickly than plants. The NEE significantly decreased with increasing SMC in shallow surface due to a hysteresis effect on water transport. The results of our study highlight the complex processes that determine how and to what extent PRE at multi-temporal scale and SMC at different depths affect the carbon flux response in a water-limited grassland. Copyright © 2018 Elsevier B.V. All rights reserved.

Using the CMB angular power spectrum to study Dark Matter-photon interactions

International Nuclear Information System (INIS)

Wilkinson, Ryan J.; Boehm, Céline; Lesgourgues, Julien

2014-01-01

In this paper, we explore the impact of Dark Matter-photon interactions on the CMB angular power spectrum. Using the one-year data release of the Planck satellite, we derive an upper bound on the Dark Matter-photon elastic scattering cross section of σ DM−γ ≤ 8 × 10 −31 (m DM /GeV) cm 2 (68% CL) if the cross section is constant and a present-day value of σ DM−γ ≤ 6 × 10 −40 (m DM /GeV) cm 2 (68% CL) if it scales as the temperature squared. For such a limiting cross section, both the B-modes and the TT angular power spectrum are suppressed with respect to ΛCDM predictions for ℓ∼>500 and ℓ∼>3000 respectively, indicating that forthcoming data from CMB polarisation experiments and Planck could help to constrain and characterise the physics of the dark sector. This essentially initiates a new type of dark matter search that is independent of whether dark matter is annihilating, decaying or asymmetric. Thus, any CMB experiment with the ability to measure the temperature and/or polarisation power spectra at high ℓ should be able to investigate the potential interactions of dark matter and contribute to our fundamental understanding of its nature

Quantum-gravity fluctuations and the black-hole temperature

Energy Technology Data Exchange (ETDEWEB)

Hod, Shahar [The Ruppin Academic Center, Emeq Hefer (Israel); The Hadassah Institute, Jerusalem (Israel)

2015-05-15

Bekenstein has put forward the idea that, in a quantum theory of gravity, a black hole should have a discrete energy spectrum with concomitant discrete line emission. The quantized black-hole radiation spectrum is expected to be very different from Hawking's semi-classical prediction of a thermal black-hole radiation spectrum. One naturally wonders: Is it possible to reconcile the discrete quantum spectrum suggested by Bekenstein with the continuous semi-classical spectrum suggested by Hawking? In order to address this fundamental question, in this essay we shall consider the zero-point quantum-gravity fluctuations of the black-hole spacetime. In a quantum theory of gravity, these spacetime fluctuations are closely related to the characteristic gravitational resonances of the corresponding black-hole spacetime. Assuming that the energy of the black-hole radiation stems from these zero-point quantum-gravity fluctuations of the black-hole spacetime, we derive the effective temperature of the quantized black-hole radiation spectrum. Remarkably, it is shown that this characteristic temperature of the discrete (quantized) black-hole radiation agrees with the well-known Hawking temperature of the continuous (semi-classical) black-hole spectrum. (orig.)

Quantum-gravity fluctuations and the black-hole temperature

International Nuclear Information System (INIS)

Hod, Shahar

2015-01-01

Bekenstein has put forward the idea that, in a quantum theory of gravity, a black hole should have a discrete energy spectrum with concomitant discrete line emission. The quantized black-hole radiation spectrum is expected to be very different from Hawking's semi-classical prediction of a thermal black-hole radiation spectrum. One naturally wonders: Is it possible to reconcile the discrete quantum spectrum suggested by Bekenstein with the continuous semi-classical spectrum suggested by Hawking? In order to address this fundamental question, in this essay we shall consider the zero-point quantum-gravity fluctuations of the black-hole spacetime. In a quantum theory of gravity, these spacetime fluctuations are closely related to the characteristic gravitational resonances of the corresponding black-hole spacetime. Assuming that the energy of the black-hole radiation stems from these zero-point quantum-gravity fluctuations of the black-hole spacetime, we derive the effective temperature of the quantized black-hole radiation spectrum. Remarkably, it is shown that this characteristic temperature of the discrete (quantized) black-hole radiation agrees with the well-known Hawking temperature of the continuous (semi-classical) black-hole spectrum. (orig.)

Subgingival temperature and microbiota in initial periodontitis.

Science.gov (United States)

Maiden, M F; Tanner, A C; Macuch, P J; Murray, L; Kent, R L

1998-10-01

The association between subgingival temperature, other clinical characteristics, and the subgingival microbiota was examined in adult subjects with initial periodontitis and differing levels of gingival inflammation. 43 subjects were measured at 6 sites per tooth for pocket depth, attachment level, presence of plaque, gingival redness, bleeding on probing and subgingival temperature at 3-month intervals for 1 year. Subgingival plaque was sampled from 15 initial active periodontitis sites (10 subjects), 121 gingivitis, sites (20 subjects) and 202 healthy sites (13 subjects), and included the 5 hottest and 5 coldest sites in each subject. Plaque samples were analyzed for 13 subgingival species using whole-genomic DNA probes. The major influences on the subgingival microbiota were the clinical status of sites, pocket depth, and the presence of supragingival plaque. No significant association between species and site temperature was observed. Initial active sites were associated with Bacteroides forsythus and Campylobacter rectus, and had a higher mean subgingival temperature and deeper mean pocket depth than inactive sites. A weak association between pocket depth and site temperature was noted. The major influence on subgingival temperature of sites was the anterior to posterior anatomical temperature gradient in the mandible and maxilla.

Temperature profile and water depth data collected from IOWA using BT and XBT casts in the North Pacific Ocean from 31 May 1985 to 23 March 1990 (NODC Accession 9000092)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The water depth and temperature data was collected using two dozen different ships through a grant to Dr. Douglas C. Biggs MMS # 14-35-0001-30501. The data was...

Fatigue limit of polycrystalline zirconium oxide ceramics: effect of grinding and low-temperature aging

NARCIS (Netherlands)

Pereira, G.K.R.; Silvestri, T.; Amaral, M.; Rippe, M.P.; Kleverlaan, C.J.; Valandro, L.F.

2016-01-01

The following study aimed to evaluate the effect of grinding and low-temperature aging on the fatigue limit of Y-TZP ceramics for frameworks and monolithic restorations. Disc specimens from each ceramic material, Lava Frame (3M ESPE) and Zirlux FC (Ivoclar Vivadent) were manufactured according to

Buoyancy frequency profiles and internal semidiurnal tide turning depths in the oceans

OpenAIRE

King, B.; Stone, M.; Zhang, H.P.; Gerkema, T.; Marder, M.; Scott, R.B.; Swinney, H.L.

2012-01-01

We examine the possible existence of internal gravity wave "turning depths," depths below which the local buoyancy frequency N(z) becomes smaller than the wave frequency. At a turning depth, incident gravity waves reflect rather than reaching the ocean bottom as is generally assumed. Here we consider internal gravity waves at the lunar semidiurnal (M-2) tidal frequency, omega(M2). Profiles of N-2(z) (the quantity in the equations of motion) are computed using conductivity, temperature, and de...

Extreme temperature robust optical sensor designs and fault-tolerant signal processing

Science.gov (United States)

Riza, Nabeel Agha [Oviedo, FL; Perez, Frank [Tujunga, CA

2012-01-17

Silicon Carbide (SiC) probe designs for extreme temperature and pressure sensing uses a single crystal SiC optical chip encased in a sintered SiC material probe. The SiC chip may be protected for high temperature only use or exposed for both temperature and pressure sensing. Hybrid signal processing techniques allow fault-tolerant extreme temperature sensing. Wavelength peak-to-peak (or null-to-null) collective spectrum spread measurement to detect wavelength peak/null shift measurement forms a coarse-fine temperature measurement using broadband spectrum monitoring. The SiC probe frontend acts as a stable emissivity Black-body radiator and monitoring the shift in radiation spectrum enables a pyrometer. This application combines all-SiC pyrometry with thick SiC etalon laser interferometry within a free-spectral range to form a coarse-fine temperature measurement sensor. RF notch filtering techniques improve the sensitivity of the temperature measurement where fine spectral shift or spectrum measurements are needed to deduce temperature.

Measurement of the temperature of the neutrons in reactor G1; Mesure de la temperature des neutrons dans la pile G1

Energy Technology Data Exchange (ETDEWEB)

Raievski, V; Sautiez, B [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1957-07-01

A precise experimental method has been adapted to the analysis of the spectrum of neutrons in the thermal region. This method uses the technique of modulation applied to a beam of neutrons issuing from a characteristic point in the pile. The analysis of the spectrum is made by adjusting, by the method of least squares, an analytical form to the experimental results. In this report are given the results obtained with a beam from the centre of the moderator of G1. The spectrum of this beam essentially represents the spectrum of the neutrons in the moderator. The most probable velocity was determined by means of Maxwell's functions. The measurements were made of different moderator temperatures between 304 deg. K and 435 deg. K. (author) [French] Une methode experimentale precise a ete mise au point pour l'analyse du spectre des neutrons dans le domaine thermique. Cette methode utilise la technique de la modulation appliquee a un faisceau de neutrons issu d'un point caracteristique de la pile. L'analyse du spectre est faite en ajustant par la methode des moindres carres une forme analytique aux resultats experimentaux. Dans ce rapport, on donne les resultats obtenus sur un faisceau du centre du moderateur de G1. Le spectre de ce faisceau represente convenablement le spectre des neutrons dans le moderateur. On s'est limite ici a une fonction de Maxwell dont on a recherche la vitesse la plus probable. Les mesures ont ete faites avec une temperature du moderateur variant entre 304 deg. K et 435 deg. K. (auteur)

[Measurement of plasma parameters in slot microplasma by optical emission spectrum].

Science.gov (United States)

Dong, Li-Fang; Lü, Ying-Hui; Liu, Wei-Yuan; Yue, Han; Lu, Ning; Li, Xin-Chun

2010-12-01

Slot microplasma was generated in argon and air mixture by using dielectric barrier discharge device with two parallel water electrodes. The molecular vibrational temperature, molecular rotational temperature and average electron energy of the slot plasma were studied by optical emission spectrum. The molecular vibrational temperature was calculated using the second positive system of nitrogen molecules ( C3 pi(u) --> B3 pi(g)). The molecular rotational temperature was calculated using the first negative system of nitrogen molecular ions ( B 2sigma(u)+ --> X sigma(g)+). The relative intensities of the first negative system of nitrogen molecular ions (391.4 nm) and nitrogen molecules in the excitation level (337.1 nm) emission spectrum line were measured for studying the variations of electron energy. It was found that the molecular vibrational temperature, molecular rotational temperature and average electron energy decrease with gas pressure increasing.

The Antiproton Depth Dose Curve Measured with Alanine Detectors

DEFF Research Database (Denmark)

Bassler, Niels; Hansen, Johnny Witterseh; Palmans, Hugo

2008-01-01

In this paper we report on the measurement of the antiproton depth dose curve, with alanine detectors. The results are compared with simulations using the particle energy spectrum calculated by FLUKA, and using the track structure model of Hansen et Olsen for conversion of calculated dose...... into response. A good agreement was observed between the measured and calculated relative effectiveness although a slight underestimation of the calculated values in the Bragg peak remains unexplained. The model prediction of response of alanine towards heavy charged particles encourages future use...... of the alanine detectors for dosimetry of mixed radiation fields....

Dragon kings of the deep sea: marine particles deviate markedly from the common number-size spectrum.

Science.gov (United States)

Bochdansky, Alexander B; Clouse, Melissa A; Herndl, Gerhard J

2016-03-04

Particles are the major vector for the transfer of carbon from the upper ocean to the deep sea. However, little is known about their abundance, composition and role at depths greater than 2000 m. We present the first number-size spectrum of bathy- and abyssopelagic particles to a depth of 5500 m based on surveys performed with a custom-made holographic microscope. The particle spectrum was unusual in that particles of several millimetres in length were almost 100 times more abundant than expected from the number spectrum of smaller particles, thereby meeting the definition of "dragon kings." Marine snow particles overwhelmingly contributed to the total particle volume (95-98%). Approximately 1/3 of the particles in the dragon-king size domain contained large amounts of transparent exopolymers with little ballast, which likely either make them neutrally buoyant or cause them to sink slowly. Dragon-king particles thus provide large volumes of unique microenvironments that may help to explain discrepancies in deep-sea biogeochemical budgets.

Temperature profile and water depth data collected from USS THACH using BT and XBT casts in the Persian Sea from 04 December 1987 to 08 December 1987 (NODC Accession 8800030)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USS THACH in the Persian Sea. Data were collected from 04 December 1987 to 08...

REPEATABILITY AND ACCURACY OF EXOPLANET ECLIPSE DEPTHS MEASURED WITH POST-CRYOGENIC SPITZER

Energy Technology Data Exchange (ETDEWEB)

Ingalls, James G.; Krick, J. E.; Carey, S. J.; Stauffer, John R.; Lowrance, Patrick J.; Grillmair, Carl J.; Capak, Peter; Glaccum, William; Laine, Seppo; Surace, Jason; Storrie-Lombardi, Lisa [Spitzer Science Center, California Institute of Technology, 1200 E California Boulevard, Mail Code 314-6, Pasadena, CA 91125 (United States); Buzasi, Derek [Department of Chemistry and Physics, Florida Gulf Coast University, Fort Myers, FL 33965 (United States); Deming, Drake [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Diamond-Lowe, Hannah; Stevenson, Kevin B. [Department of Astronomy and Astrophysics, University of Chicago, 5640 S Ellis Avenue, Chicago, IL 60637 (United States); Evans, Thomas M. [School of Physics, University of Exeter, EX4 4QL Exeter (United Kingdom); Morello, G. [Department of Physics and Astronomy, University College London, Gower Street, WC1 E6BT (United Kingdom); Wong, Ian, E-mail: ingalls@ipac.caltech.edu [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States)

2016-08-01

We examine the repeatability, reliability, and accuracy of differential exoplanet eclipse depth measurements made using the InfraRed Array Camera (IRAC) on the Spitzer Space Telescope during the post-cryogenic mission. We have re-analyzed an existing 4.5 μ m data set, consisting of 10 observations of the XO-3b system during secondary eclipse, using seven different techniques for removing correlated noise. We find that, on average, for a given technique, the eclipse depth estimate is repeatable from epoch to epoch to within 156 parts per million (ppm). Most techniques derive eclipse depths that do not vary by more than a factor 3 of the photon noise limit. All methods but one accurately assess their own errors: for these methods, the individual measurement uncertainties are comparable to the scatter in eclipse depths over the 10 epoch sample. To assess the accuracy of the techniques as well as to clarify the difference between instrumental and other sources of measurement error, we have also analyzed a simulated data set of 10 visits to XO-3b, for which the eclipse depth is known. We find that three of the methods (BLISS mapping, Pixel Level Decorrelation, and Independent Component Analysis) obtain results that are within three times the photon limit of the true eclipse depth. When averaged over the 10 epoch ensemble,  5 out of 7 techniques come within 60 ppm of the true value. Spitzer exoplanet data, if obtained following current best practices and reduced using methods such as those described here, can measure repeatable and accurate single eclipse depths, with close to photon-limited results.

Daily extreme temperature multifractals in Catalonia (NE Spain)

International Nuclear Information System (INIS)

Burgueño, A.; Lana, X.; Serra, C.; Martínez, M.D.

2014-01-01

The multifractal character of the daily extreme temperatures in Catalonia (NE Spain) is analyzed by means of the multifractal detrended fluctuation analysis (MF-DFA) applied to 65 thermometric records covering years 1950–2004. Although no clear spatial patterns of the multifractal spectrum parameters appear, factor scores deduced from Principal Component analysis indicate some signs of spatial gradients. Additionally, the daily extreme temperature series are classified depending on their complex time behavior, through four multifractal parameters (Hurst exponent, Hölder exponent with maximum spectrum, spectrum asymmetry and spectrum width). As a synthesis of the three last parameters, a basic measure of complexity is proposed through a normalized Complexity Index. Its regional behavior is found to be free of geographical dependences. This index represents a new step towards the description of the daily extreme temperatures complexity.

Daily extreme temperature multifractals in Catalonia (NE Spain)

Energy Technology Data Exchange (ETDEWEB)

Burgueño, A. [Departament d' Astronomia i Meteorologia, Universitat de Barcelona, Barcelona (Spain); Lana, X., E-mail: francisco.javier.lana@upc.edu [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Barcelona (Spain); Serra, C. [Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, Barcelona (Spain); Martínez, M.D. [Departament de Física Aplicada, Universitat Politècnica de Catalunya, Barcelona (Spain)

2014-02-01

The multifractal character of the daily extreme temperatures in Catalonia (NE Spain) is analyzed by means of the multifractal detrended fluctuation analysis (MF-DFA) applied to 65 thermometric records covering years 1950–2004. Although no clear spatial patterns of the multifractal spectrum parameters appear, factor scores deduced from Principal Component analysis indicate some signs of spatial gradients. Additionally, the daily extreme temperature series are classified depending on their complex time behavior, through four multifractal parameters (Hurst exponent, Hölder exponent with maximum spectrum, spectrum asymmetry and spectrum width). As a synthesis of the three last parameters, a basic measure of complexity is proposed through a normalized Complexity Index. Its regional behavior is found to be free of geographical dependences. This index represents a new step towards the description of the daily extreme temperatures complexity.

Temperature profile and water depth collected from ZAMBEZE and other platforms using BT and XBT casts in the Atlantic Ocean from 21 July 1981 to 02 December 1985 (NODC Accession 8600293)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the ZAMBEZE and other platforms in the Northeast / Southwest Atlantic Ocean. Data...

Large reptiles and cold temperatures: Do extreme cold spells set distributional limits for tropical reptiles in Florida?

Science.gov (United States)

Mazzotti, Frank J.; Cherkiss, Michael S.; Parry, Mark; Beauchamp, Jeff; Rochford, Mike; Smith, Brian J.; Hart, Kristen M.; Brandt, Laura A.

2016-01-01

Distributional limits of many tropical species in Florida are ultimately determined by tolerance to low temperature. An unprecedented cold spell during 2–11 January 2010, in South Florida provided an opportunity to compare the responses of tropical American crocodiles with warm-temperate American alligators and to compare the responses of nonnative Burmese pythons with native warm-temperate snakes exposed to prolonged cold temperatures. After the January 2010 cold spell, a record number of American crocodiles (n = 151) and Burmese pythons (n = 36) were found dead. In contrast, no American alligators and no native snakes were found dead. American alligators and American crocodiles behaved differently during the cold spell. American alligators stopped basking and retreated to warmer water. American crocodiles apparently continued to bask during extreme cold temperatures resulting in lethal body temperatures. The mortality of Burmese pythons compared to the absence of mortality for native snakes suggests that the current population of Burmese pythons in the Everglades is less tolerant of cold temperatures than native snakes. Burmese pythons introduced from other parts of their native range may be more tolerant of cold temperatures. We documented the direct effects of cold temperatures on crocodiles and pythons; however, evidence of long-term effects of cold temperature on their populations within their established ranges remains lacking. Mortality of crocodiles and pythons outside of their current established range may be more important in setting distributional limits.

Dworshak Dam impacts assessment and fisheries investigation -- Kokanee depth distribution in Dworshak Reservoir and implications toward minimizing entrainment. Annual progress report, January--December 1994

International Nuclear Information System (INIS)

Maiolie, M.A.; Elam, S.

1996-10-01

The authors measured the day and night depth distribution of kokanee Oncorhynchus nerka kennerlyi directly upstream of Dworshak Dam from October 1993 to December 1994 using split-beam hydroacoustics. At night most kokanee (70%) were distributed in a diffuse layer about 10 m thick. The depth of the layer varied with the season and ranged from 30 to 40 m deep during winter and from 15 to 25 m deep during summer. Nighttime depth of the kokanee layer during summer roughly corresponded to a zone where water temperatures ranged from 7 C to 12 C. Daytime kokanee distribution was much different with kokanee located in dense schools. Most kokanee (70%) were found in a 5--15 m thick layer during summer. Daytime depth distribution was also shallowest during fall and deepest during winter. Dworshak Dam has structures which can be used for selective water withdrawal and can function in depth ranges that will avoid the kokanee layer. Temperature constraints limit the use of selective withdrawal during the spring, summer, and fall, but in the winter, water is nearly isothermal and the full range of selector gate depths may be utilized. From October 1993 to February 1994, selector gates were positioned to withdraw water from above the kokanee layer. The discharge pattern also changed with more water being released during May and July, and less water being released during fall and winter. A combination of these two changes is thought to have increased kokanee densities to a record high of 69 adults/ha

Adaptation of spectral distribution of synchrotron radiation to X-ray depth lithography

International Nuclear Information System (INIS)

Maid, B.; Ehrfeld, W.; Hormes, J.; Mohr, J.; Muenchmeyer, D.

1989-05-01

Plastic microstructures with extremly high aspect ratios can be fabricated by X-ray depth lithography with synchrotron radiation. In order to minimize the expenditure in terms of irradiation the spectrum of the synchrotron radiation source has to be adapted to the irradiation task. It is characterized by the height of the microstructure and the maximum admissible dose ratio permitting the resist to develop in the depth without destruction of the surface as a result of radiation damage. Expenditure in terms of irradiation is minimum if an ideal sharp cutoff filter, profiting from the maximum permissible dose ratio, filters out the long-waved portion of the spectrum without attenuating the intensity of the short-waved portion of the spectrum. By the example of a typical resist-developer system the location of the filter edge was determined at different structural heights for the Bonn synchrotron and the ELSA electron stretching facility (Bonn). To be capable of building the ideal sharp cutoff filter, the thickness of an absorber was adapted for different materials in such a way that the maximum permissible dose ratio was obtained. If a thin reflector foil is used which is hit by glazing radiation, the expenditure in terms of irradiation can be reduced because of the steeper filter characteristic of resists with small maximum dose ratios. The short-waved transmitted beam is used for irradiation, with the filter edge set by the angle between the foil and the beam. The technical feasibility of a reflection filter was demonstrated on the model of a reflector foil consisting of 30 nm titanium on 7.5 μm polyimide substrate by transmission measurements performed at different angles. (orig./HP) [de

Multiple scattering effects in depth resolution of elastic recoil detection

Energy Technology Data Exchange (ETDEWEB)

Wielunski, L.S.; Harding, G.L. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Telecommunications and Industrial Physics; Szilagyi, E. [KFKI Research Institute for Particle and Nuclear Physics, Budapest, (Hungary)

1998-06-01

Elastic Recoil Detection (ERD) is used to profile hydrogen and other low mass elements in thin films at surface and interfaces in a similar way that Rutherford Backscattering Spectroscopy (RBS) is used to detect and profile heavy elements. It is often assumed that the depth resolutions of these two techniques are similar. However, in contrast to typical RBS, the depth resolution of ERD is limited substantially by multiple scattering. In experimental data analysis and/or spectra simulations of a typical RBS measurement multiple scattering effects are often ignored. Computer programs used in IBA, such as RUMP, HYPRA or RBX do not include multiple scattering effects at all. In this paper, using practical thin metal structures with films containing intentionally introduced hydrogen, we demonstrate experimental ERD depth resolution and sensitivity limitations. The effects of sample material and scattering angle are also discussed. (authors). 19 refs., 4 figs.

Evidence of weak pair coupling in the penetration depth of bi-based high-Tc superconductors

International Nuclear Information System (INIS)

Thompson, J.R.; Sun, Yang Ren; Ossandon, J.G.; Christen, D.K.; Chakoumakos, B.C.; Sales, B.C.; Kerchner, H.R.; Sonder, E.

1990-01-01

The magnetic penetration depth λ(T) has been investigated in Bi(Pb)SrCaCuO high-T c compounds having 2- and 3-layers of copper-oxygen per unit cell. Studies of the magnetization in the vortex state were employed and the results were compared with weak and strong coupling calculations. The temperature dependence of λ is described well by BCS theory in the clean limit, giving evidence for weak pair coupling in this family of materials. For the short component of the λ tensor, we obtain values of 292 and 220 nm (T = 0) for Bi-2212 and (BiPb)-2223, respectively

The threshold photoelectron spectrum of mercury

International Nuclear Information System (INIS)

Rojas, H; Dawber, G; Gulley, N; King, G C; Bowring, N; Ward, R

2013-01-01

The threshold photoelectron spectrum of mercury has been recorded over the energy range (10–40 eV) which covers the region from the lowest state of the singly charged ion, 5d 10 6s( 2 S 1/2 ), to the double charged ionic state, 5d 9 ( 2 D 3/2 )6s( 1 D 2 ). Synchrotron radiation has been used in conjunction with the penetrating-field threshold-electron technique to obtain the spectrum with high resolution. The spectrum shows many more features than observed in previous photoemission measurements with many of these assigned to satellite states converging to the double ionization limit. (paper)

Phonon response of some heavy Fermion systems in dynamic limit

Science.gov (United States)

Sahoo, Jitendra; Shadangi, Namita; Nayak, Pratibindhya

2017-05-01

The phonon excitation spectrum of some Heavy Fermion (HF) systems in the presence of electron-phonon interaction is studied in the dynamic limit (ω≠0). The renormalized excitation phonon frequencies (ω˜ = ω/ω0) are evaluated through Periodic Anderson Model (PAM) in the presence of electron-phonon interaction using Zubarev-type double time temperature-dependent Green function. The calculated renormalized phonon energy is analyzed through the plots of (ω˜ = ω/ω0) against temperature for different system parameters like effective coupling strength ‘g’ and the position of f-level ‘d’. The observed behavior is analyzed and found to agree with the general features of HF systems found in experiments. Further, it is observed that in finite but small q-values the propagating phonons harden and change to localized peaks.

Temperature profile and water depth data collected from USS McInerney from expendable bathythermographs (XBT) in the Red Sea from 07 December 1992 to 28 December 1992 (NODC Accession 9300017)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Temperature profile and water depth data were collected using BT and XBT casts from the USS McInerney in the Red Sea. Data were collected from 07 December 1992 to 28...

Influence of Non-uniform Temperature Field on Spectra of Fibre Bragg Grating

International Nuclear Information System (INIS)

Yan, Zhou; Xing-Fang, He; Xiao-Yong, Fang; Jie, Yuan; Li-Qun, Yin; Mao-Sheng, Cao

2009-01-01

We simulate the spectrum characteristics of fibre Bragg grating (FBG) with non-uniform temperature using the transmission matrix method, and the results are analysed. It is found that firstly the modulated coefficient of average refractive index is a very important parameter that influences the spectrum characteristic of the fibre Bragg grating, and secondly the spectrum curves are different in different temperature fields at the same parameter. Hence, we can determine the metrical temperature by analysing the spectrum of fibre Bragg grating

Examination for optimization of synchrotron radiation spectrum for the x ray depth lithography

Science.gov (United States)

Dany, Raimund

1992-06-01

The effect of reducing the vertical distribution of synchrotron radiation on its spectral distribution is examined through resin irradiation. The resulting filter effect is compared to that of absorption filters. Transmission coefficients of titanium, gold, and polyamide were calculated from linear absorption coefficients with the Beer law. The use of a diaphragm in X-ray depth lithography, which is the first step of the LIGA (Lithography Galvanoforming Molding) process, is discussed. A calorimetric device for determining the synchrotron radiation power and distribution was developed and tested. Measurements at the ELSA storage ring show a strong dependence of the vertical emittance on the electron current.

Controls on sublithospheric small-scale convection on Curie depths

Science.gov (United States)

Likerman, Jeremias; Zlotnik, Sergio; Chun-Feng, Li

2017-04-01

As the ocean lithosphere cools and thickens, its bottom layer goes unstable leading to sub-lithospheric small-scale convection (SSC). Since SSC was originally proposed, there have been considerable efforts regarding the understanding of the physics that rules the thermal instabilities of the SSC (e.g. Dumoulin et al, 1999; Solomatov and Moresi, 2000). Over the last several years, it is understood that the interaction between the plate movement and the SSC tends to form longitudinal (LRs or also called 'Richter rolls') and transverse rolls (TRs), of which the axis is parallel and perpendicular to the plate motion, respectively. The geometry of these rolls have been been recently inferred by Li et al (2013) using Curie depths from the North Atlantic as proxies for plates temperatures. They showed that Curie depths have a large oscillating and heterogeneous patterns that could be related to SSC. In the North Atlantic transverse rolls seem predominant. In this work we analyze, by means of 3D dynamical numerical simulations, the influence of SSC on the Curie depths patterns observed in the North Atlantic and Pacific plates. We investigate the behaviour of the Curie isotherms trying to determine if SSC is able to reproduce the observed data, and the influence of several poorly constrained rheological parameters. Our numerical simulations show that: a) using realistic laboratory-constrained rheologies and temperature it is possible to modify temperatures as low as those at Curie depths; b) transverse rolls are generated as well as longitudinal rolls on those isotherms; c) the spreading rate is a first order control on the developing of transverse rolls. References Dumoulin, C., Doin, M. P., & Fleitout, L. (1999). Heat transport in stagnant lid convection with temperature-and pressure-dependent Newtonian or non-Newtonian rheology. Journal of Geophysical Research: Solid Earth, 104(B6), 12759-12777. Li, C. F., Wang, J., Lin, J., & Wang, T. (2013). Thermal evolution of the