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1

Calibration procedure for focal plane array cameras and noise equivalent material loss for quantitative thermographic NDT  

SciTech Connect

In this paper, a complete procedure is proposed for the calibration of a focal plane array in quantitative infrared nondestructive testing (NDT). This procedure includes vignetting correction and gray level conversion into temperature. A noise analysis is also presented in the context of pulsed infrared thermography applied to NDT. In this analysis, the authors introduce a new parameter, the noise equivalent material loss (NEML). The NEML is a global figure of merit which allows the comparison of different experimental set-ups for infrared pulsed thermography. Theory, experimental validation of the proposed concepts, and comparison with a few infrared scanning thermal imagers are presented as well.

Marinetti, S.; Maldague, X. [Univ. Laval, Quebec City, Quebec (Canada). Electrical and Computer Engineering Dept.; Prystay, M. [National Research Council of Canada, Boucherville, Quebec (Canada)

1997-03-01

2

Noise equivalent circuit of a semiconductor laser diode  

NASA Technical Reports Server (NTRS)

A small-signal model of a semiconductor laser is extended to include the effects of intrinsic noise by adding current and voltage noise sources. The current noise source represents the shot noise of carrier recombination, while the voltage noise source represents the random process of simulated emission. The usefulness of the noise equivalent circuit is demonstrated by calculating the modulation and noise characteristics of a current-driven diode as a function of bias current and frequency.

Harder, C.; Margalit, S.; Yariv, A.; Katz, J.; Shacham, J.

1982-01-01

3

Plasma wave detection of terahertz radiation by silicon field effects transistors: Responsivity and noise equivalent power  

NASA Astrophysics Data System (ADS)

Si metal oxide semiconductor field effect transistors (MOSFETs) with the gate lengths of 120-300 nm have been studied as room temperature plasma wave detectors of 0.7 THz electromagnetic radiation. In agreement with the plasma wave detection theory, the response was found to depend on the gate length and the gate bias. The obtained values of responsivity (<=200 V/W) and noise equivalent power (>=10-10 W/Hz0.5) demonstrate the potential of Si MOSFETs as sensitive detectors of terahertz radiation.

Tauk, R.; Teppe, F.; Boubanga, S.; Coquillat, D.; Knap, W.; Meziani, Y. M.; Gallon, C.; Boeuf, F.; Skotnicki, T.; Fenouillet-Beranger, C.; Maude, D. K.; Rumyantsev, S.; Shur, M. S.

2006-12-01

4

Measuring PET scanner sensitivity: relating countrates to image signal-to-noise ratios using noise equivalents counts  

Microsoft Academic Search

True coincidence count (TCC) and noise equivalent count (NEC) curves were measured with a standardized 20-cm-diameter nylon cylinder for five different CTI\\/Siemens PET (positron emission tomography) scanners with several scanner-collimator combinations: (1) 831\\/08-12 with 1-mm collimator septa; (2) 933\\/08-12 and 933\\/08-16 with 3?1-mm tapered collimator septa; and (3) 931\\/08-12 with 3?1-mm tapered and a 1-mm collimator septa and the 931\\/08-16

S. C. Strother; M. E. Casey; E. J. Hoffman

1990-01-01

5

Noise-equivalent power characterization of an uncooled microbolometer-based THz imaging camera  

NASA Astrophysics Data System (ADS)

A THz camera based on an uncooled microbolometer 160X120 pixel array with nominal pitch of 52 ?m has been developed at INO and initial transmission and reflection images showed promise. In the present paper, the characterization of both standard infrared and THz-optimized uncooled microbolometer pixel arrays are presented at both infrared and THz wavelengths. Measurements in the THz region has been performed using non-uniform low-power quantum-cascade laser (QCL) and uniform high-power far-infrared laser (FIR laser) beams at 3 THz and 4.25 and 2.54 THz, respectively. A measurement comparison has been achieved in the infrared using a blackbody radiation. Different methods for noise-equivalent power (NEP) measurements have been investigated. These characterization methods are promising especially for non-uniform laser beams irradiated on pixel arrays. The NEP results obtained from the different methods are in good agreement independent of the method used in the experiments. The results show a high sensitivity of the THz-optimized pixel array in the THz region. Large beam area reflection imaging of obscured materials at 2.54 THz have been performed at video rates of 30 frames per second using the THz-optimized pixel array equipped with a semi-custom fast THz objective, proving that the INO THz camera provides a promising solution for stand-alone imaging systems.

Bolduc, Martin; Terroux, Marc; Tremblay, Bruno; Marchese, Linda; Savard, Eric; Doucet, Michel; Oulachgar, Hassane; Alain, Christine; Jerominek, Hubert; Bergeron, Alain

2011-05-01

6

Reliability of predicting image signal-to-noise ratio using noise equivalent count rate in PET imaging  

PubMed Central

Purpose: Several investigators have shown that noise equivalent count rate (NECR) is linearly proportional to the square of image signal-to-noise ratio (SNR) when PET images are reconstructed using filtered back-projection. However, to our knowledge, none have shown a similar relationship in fully 3D ordered-subset expectation maximization (OSEM) reconstruction. This paper has two aims. The first is to investigate the NECR-SNR relationship for 3D-OSEM reconstruction using phantom studies while the second aim is to evaluate the NECR-SNR relationship using patient data. Methods: An anthropomorphic phantom was scanned on a GE Discovery-STE (DSTE) PET/CT scanner in 3D mode with an initial activity concentration of 66.34 kBq/cc. PET data were acquired over the lower chest/upper abdomen region in dynamic mode. The experiment was repeated with the same activity concentration on a GE Discovery-RX (DRX) scanner. Care was taken to place the phantom at identical positions in both scanners. PET data were then reconstructed using 3D Reprojection (3D-RP) and 3D-OSEM with different reconstruction parameters and the NECR and SNR for each frame/image were calculated. SNR2 was then plotted versus the NECR for each scanner, reconstruction method and parameters. In addition, 40 clinical PET/CT studies from the two scanners (20 patients/scanner) were evaluated retrospectively. The patient studies from each scanner were further divided into two subgroups of body mass indices (BMI). Each PET study was acquired in 3D mode and reconstructed using both 3D-OSEM and 3D-RP. The NECR and SNR of the bed position covering the patient liver were calculated for each patient and averaged for each subgroup. Comparisons of the NECR and SNR between scanner types and BMIs were performed using a t-test and a p value less than 0.05 was considered significant. Results: Phantom results showed that SNR2 versus NECR was linear for 3D-RP reconstruction across all activity concentration on both scanners, as expected. However, when 3D-OSEM was used, this relationship was nonlinear at activity concentrations beyond the peak NECR on both scanners. On the other hand, the plot of SNR2 versus trues count rate was linear for 3D-OSEM across all activity concentrations on both scanners independent of reconstruction parameters used. In addition, for activity concentrations <30kBq/cc, phantom results showed a higher SNR (by 12 10%; p < 0.05) and NECR for the DRX scanner compared to DSTE for 3D-RP reconstruction. However, for 3D-OSEM reconstruction, these two scanners had similar SNRs (different by 2% 9%; p > 0.05), despite having different NECRs. Patient studies showed a statistically significant difference in NECR as well as the SNR for 3D-RP reconstruction between the two scanners. However, no statistically significant difference was found for 3D-OSEM. A statistically significant difference in both NECR and SNR were found between the different BMI subgroups for both 3D-RP and 3D-OSEM reconstructions. Conclusions: For the scanners and reconstruction algorithm used in this study, our results suggest that the image SNR cannot be predicted by the NEC when using 3D-OSEM reconstruction particularly for those clinical applications requiring high activity concentration. Instead, our results suggest that image SNR varies with activity concentration and is dominated by the 3D-OSEM reconstruction algorithm and its associated parameters, while not being affected by the scanner type for the range of activity concentrations usually found in the clinic.

Chang, Tingting; Chang, Guoping; Clark, John W.; Diab, Rami H.; Rohren, Eric; Mawlawi, Osama R.

2012-01-01

7

Characterization of imaging performance in differential phase contrast CT compared with the conventional CT: Spectrum of noise equivalent quanta NEQ(k)  

SciTech Connect

Purpose: Differential phase contrast CT (DPC-CT) is emerging as a new technology to improve the contrast sensitivity of conventional attenuation-based CT. The noise equivalent quanta as a function over spatial frequency, i.e., the spectrum of noise equivalent quanta NEQ(k), is a decisive indicator of the signal and noise transfer properties of an imaging system. In this work, we derive the functional form of NEQ(k) in DPC-CT. Via system modeling, analysis, and computer simulation, we evaluate and verify the derived NEQ(k) and compare it with that of the conventional attenuation-based CT. Methods: The DPC-CT is implemented with x-ray tube and gratings. The x-ray propagation and data acquisition are modeled and simulated through Fresnel and Fourier analysis. A monochromatic x-ray source (30 keV) is assumed to exclude any system imperfection and interference caused by scatter and beam hardening, while a 360 Degree-Sign full scan is carried out in data acquisition to avoid any weighting scheme that may disrupt noise randomness. Adequate upsampling is implemented to simulate the x-ray beam's propagation through the gratings G{sub 1} and G{sub 2} with periods 8 and 4 {mu}m, respectively, while the intergrating distance is 193.6 mm (1/16 of the Talbot distance). The dimensions of the detector cell for data acquisition are 32 Multiplication-Sign 32, 64 Multiplication-Sign 64, 96 Multiplication-Sign 96, and 128 Multiplication-Sign 128 {mu}m{sup 2}, respectively, corresponding to a 40.96 Multiplication-Sign 40.96 mm{sup 2} field of view in data acquisition. An air phantom is employed to obtain the noise power spectrum NPS(k), spectrum of noise equivalent quanta NEQ(k), and detective quantum efficiency DQE(k). A cylindrical water phantom at 5.1 mm diameter and complex refraction coefficient n= 1 -{delta}+i{beta}= 1 -2.5604 Multiplication-Sign 10{sup -7}+i1.2353 Multiplication-Sign 10{sup -10} is placed in air to measure the edge transfer function, line spread function and then modulation transfer function MTF(k), of both DPC-CT and the conventional attenuation-based CT. The x-ray flux is set at 5 Multiplication-Sign 10{sup 6} photon/cm{sup 2} per projection and observes the Poisson distribution, which is consistent with that of a micro-CT for preclinical applications. Approximately 360 regions, each at 128 Multiplication-Sign 128 matrix, are used to calculate the NPS(k) via 2D Fourier transform, in which adequate zero padding is carried out to avoid aliasing in noise. Results: The preliminary data show that the DPC-CT possesses a signal transfer property [MTF(k)] comparable to that of the conventional attenuation-based CT. Meanwhile, though there exists a radical difference in their noise power spectrum NPS(k) (trait 1/|k| in DPC-CT but |k| in the conventional attenuation-based CT) the NEQ(k) and DQE(k) of DPC-CT and the conventional attenuation-based CT are in principle identical. Conclusions: Under the framework of ideal observer study, the joint signal and noise transfer property NEQ(k) and detective quantum efficiency DQE(k) of DPC-CT are essentially the same as those of the conventional attenuation-based CT. The findings reported in this paper may provide insightful guidelines on the research, development, and performance optimization of DPC-CT for extensive preclinical and clinical applications in the future.

Tang Xiangyang; Yang Yi; Tang Shaojie [Imaging and Medical Physics, Department of Radiology and Imaging Sciences, Emory University School of Medicine, 1701 Uppergate Drive, C-5018, Atlanta, Georgia 30322 (United States)

2012-07-15

8

Characterization of imaging performance in differential phase contrast CT compared with the conventional CT: Spectrum of noise equivalent quanta NEQ(k)  

PubMed Central

Purpose: Differential phase contrast CT (DPC-CT) is emerging as a new technology to improve the contrast sensitivity of conventional attenuation-based CT. The noise equivalent quanta as a function over spatial frequency, i.e., the spectrum of noise equivalent quanta NEQ(k), is a decisive indicator of the signal and noise transfer properties of an imaging system. In this work, we derive the functional form of NEQ(k) in DPC-CT. Via system modeling, analysis, and computer simulation, we evaluate and verify the derived NEQ(k) and compare it with that of the conventional attenuation-based CT. Methods: The DPC-CT is implemented with x-ray tube and gratings. The x-ray propagation and data acquisition are modeled and simulated through Fresnel and Fourier analysis. A monochromatic x-ray source (30 keV) is assumed to exclude any system imperfection and interference caused by scatter and beam hardening, while a 360 full scan is carried out in data acquisition to avoid any weighting scheme that may disrupt noise randomness. Adequate upsampling is implemented to simulate the x-ray beam's propagation through the gratings G1 and G2 with periods 8 and 4 ?m, respectively, while the intergrating distance is 193.6 mm (1/16 of the Talbot distance). The dimensions of the detector cell for data acquisition are 32 32, 64 64, 96 96, and 128 128 ?m2, respectively, corresponding to a 40.96 40.96 mm2 field of view in data acquisition. An air phantom is employed to obtain the noise power spectrum NPS(k), spectrum of noise equivalent quanta NEQ(k), and detective quantum efficiency DQE(k). A cylindrical water phantom at 5.1 mm diameter and complex refraction coefficient n = 1 ? ? + i? = 1 ?2.5604 10?7 + i1.2353 10?10 is placed in air to measure the edge transfer function, line spread function and then modulation transfer function MTF(k), of both DPC-CT and the conventional attenuation-based CT. The x-ray flux is set at 5 106 photon/cm2 per projection and observes the Poisson distribution, which is consistent with that of a micro-CT for preclinical applications. Approximately 360 regions, each at 128 128 matrix, are used to calculate the NPS(k) via 2D Fourier transform, in which adequate zero padding is carried out to avoid aliasing in noise. Results: The preliminary data show that the DPC-CT possesses a signal transfer property [MTF(k)] comparable to that of the conventional attenuation-based CT. Meanwhile, though there exists a radical difference in their noise power spectrum NPS(k) (trait 1/|k| in DPC-CT but |k| in the conventional attenuation-based CT) the NEQ(k) and DQE(k) of DPC-CT and the conventional attenuation-based CT are in principle identical. Conclusions: Under the framework of ideal observer study, the joint signal and noise transfer property NEQ(k) and detective quantum efficiency DQE(k) of DPC-CT are essentially the same as those of the conventional attenuation-based CT. The findings reported in this paper may provide insightful guidelines on the research, development, and performance optimization of DPC-CT for extensive preclinical and clinical applications in the future.

Tang, Xiangyang; Yang, Yi; Tang, Shaojie

2012-01-01

9

Absolute response and noise equivalent power of cyclotron resonance-assisted InSb detectors at submillimeter wavelengths  

NASA Technical Reports Server (NTRS)

Spectra are presented of the responsivity and noise equivalent power (NEP) of liquid-helium-cooled InSb detectors as a function of magnetic field in the range 20-110 per cm. The measurements are all made using a Fourier transform spectrometer with thermal sources. The results show a discernable peak in the detector response at the conduction electron cyclotron resonance (CCR) frequency for magnetic fields as low as 3 kG. The magnitude of responsivity at the resonance peaks is roughly constant with magnetic field and is comparable to the low-frequency hot-electron bolometer response. The NEP at the peaks is found to be comparable to the best long wavelength results previously reported. For example, NEP = 4.5 x 10 to the 13th W/(square root of Hz) at 4.2 K, 6 kG, and 40 per cm was measured. The InSb CCR will provide a much improved detector for laboratory spectroscopy, as compared with hot electron bolometers, in the 20-100 per cm range.

Brown, E. R.; Wengler, M. J.; Phillips, T. G.

1985-01-01

10

Noise equivalent circuit of a two-mode semiconductor laser with the contribution of both the linear and the nonlinear gain  

Microsoft Academic Search

An equivalent circuit model of a semiconductor laser diode and its MDS (microwave and RF design systems) implementation are described that allow a straightforward calculation of the noise characteristics of a laser diode combined with electronic components. This noise equivalent circuit model that is derived from the two-mode rate equations including both the self-saturation and cross-saturation contributions to the nonlinear

Tran Thi Bich-Ha; Jean-Claude Mollier

1997-01-01

11

Validation of the land-surface temperature products retrieved from Terra Moderate Resolution Imaging Spectroradiometer data  

Microsoft Academic Search

This paper presents the status of land-surface temperature (LST) standard products retrieved from Earth Observing System (EOS) Moderate Resolution Imaging Spectroradiometer (MODIS) data. Based on estimates of the channel-dependence error and noise equivalent temperature difference (NEDT) and the calibration accuracy of MODIS thermalinfrared data, the impact of instrument performance on the accuracy of LST is discussed. A double-screen scheme based

Zhengming Wan; Yulin Zhang; Qincheng Zhang; Zhao-liang Li

2002-01-01

12

Microclimatic Temperature Relationships over Different Surfaces.  

ERIC Educational Resources Information Center

Describes a study of temperature variations over different surfaces in an urban campus setting. Explains that researchers sampled temperatures over grass, bare soil, gravel, concrete, and blacktop. Reports that grassy areas registered the highest morning temperatures and lowest afternoon temperatures. (SG)

Williams, Thomas B.

1991-01-01

13

Differences Between Ground and Air Temperatures  

NSDL National Science Digital Library

In developing models for climate change and weather prediction, the measurements of surface and near-surface temperature are an important factor in the modeling process. As the Sun heats the Earth's surface, the atmosphere is warmed from below by the processes of conduction and convection from the surface. However, near-surface air temperature (approximately 10 meters above the surface) is often different than the surface temperature. The different properties of air, land and water, such as density or heat capacity, as well as seasonal changes of the surface type, can explain these differences. In this lesson, students will explore real NASA satellite data to compare the near-surface air temperature and surface temperature in different climate regions. They will then draw conclusions about the seasonal patterns and the effect of the underlying surface on the air temperature.

14

Electron temperature differences and double layers  

NASA Technical Reports Server (NTRS)

Electron temperature differences across plasma double layers are studied experimentally. It is shown that the temperature differences across a double layer can be varied and are not a result of thermalization of the bump-on-tail distribution. The implications of these results for electron thermal energy transport in laser-pellet and tandem-mirror experiments are also discussed.

Chan, C.; Hershkowitz, N.; Lonngren, K. E.

1983-01-01

15

Component analysis of a new Solid State X-ray Image Intensifier (SSXII) using photon transfer and Instrumentation Noise Equivalent Exposure (INEE) measurements  

PubMed Central

The SSXII is a novel x-ray imager designed to improve upon the performance limitations of conventional dynamic radiographic/fluoroscopic imagers related to resolution, charge-trapping, frame-rate, and instrumentation-noise. The SSXII consists of a CsI:Tl phosphor coupled via a fiber-optic taper (FOT) to an electron-multiplying CCD (EMCCD). To facilitate investigational studies, initial designs enable interchangeability of such imaging components. Measurements of various component and configuration characteristics enable an optimization analysis with respect to overall detector performance. Photon transfer was used to characterize the EMCCD performance including ADC sensitivity, read-noise, full-well capacity and quantum efficiency. X-ray sensitivity was measured using RQA x-ray spectra. Imaging components were analyzed in terms of their MTF and transmission efficiency. The EMCCD was measured to have a very low effective read-noise of less than 1 electron rms at modest EMCCD gains, which is more than two orders-of-magnitude less than flat panel (FPD) and CMOS-based detectors. The variable signal amplification from 1 to 2000 times enables selectable sensitivities ranging from 8.5 (168) to over 15k (300k) electrons per incident x-ray photon with (without) a 4:1 FOT; these sensitivities could be readily increased with further component optimization. MTF and DQE measurements indicate the SSXII performance is comparable to current state-of-the-art detectors at low spatial frequencies and far exceeds them at higher spatial frequencies. The instrumentation noise equivalent exposure (INEE) was measured to be less than 0.3 ?R out to 10 cycles/mm, which is substantially better than FPDs. Component analysis suggests that these improvements can be substantially increased with further detector optimization.

Kuhls-Gilcrist, Andrew; Bednarek, Daniel R.; Rudin, Stephen

2009-01-01

16

Casimir forces between cylinders at different temperatures  

NASA Astrophysics Data System (ADS)

We study Casimir interactions between cylinders in thermal nonequilibrium, where the objects as well as the environment are held at different temperatures. We provide the general formula for the force, in a one reflection approximation, for cylinders of arbitrary radii and optical properties. As is the case for equilibrium, we find that the force for optically diluted cylinders can be obtained by appropriate summation of the corresponding result for spheres. We find that the nonequilibrium forces are generally larger than their equilibrium counterpart at separations greater than the thermal wavelength. They may also exhibit oscillations as function of separation, leading to stable points of zero net force. These effects are particularly pronounced for thin conducting cylinders (e.g. 40 nm diameter nanowires of tungsten) due to their large emissivity.

Golyk, Vladyslav A.; Krger, Matthias; Reid, M. T. Homer; Kardar, Mehran

2012-03-01

17

A Compilation and Historical Review of Temperature Scale Differences.  

National Technical Information Service (NTIS)

A brief review is given of temperature scales, their definition, and measurement. Methods of practical temperature measurement are described. Differences between internationally accepted temperature scales are presented graphically and in tabular form; co...

J. G. Hust

1969-01-01

18

Electrically induced temperature difference and deformation in hardened cement pastes  

SciTech Connect

Electromechanical effect of hardened cement paste beam is investigated in this paper. When an external electrical current is applied to the electrodes attached to opposite surfaces of a cement beam, it is found that temperature on the positive electrode is always higher than that on the negative electrode. The sign of electrically induced temperature difference is determined by the direction of applied electrical current. Electrically induced temperature difference makes the beam bend towards the surface with a higher temperature. Both electrically induced temperature difference and electroosmosis lead to electromechanical effect of hardened cement paste. Finally, electromechanical effect becomes more obvious by adding NaCl to cement paste.

Sun Mingqing [Department of Engineering Structures and Mechanics, Wuhan University of Technology, Wuhan 430070 (China)]. E-mail: sunmingqing@yahoo.com; Wang Xiaoying [Department of Engineering Structures and Mechanics, Wuhan University of Technology, Wuhan 430070 (China); Zhao Kairui [Department of Engineering Structures and Mechanics, Wuhan University of Technology, Wuhan 430070 (China); Li Zhuoqiu [Department of Engineering Structures and Mechanics, Wuhan University of Technology, Wuhan 430070 (China)

2006-12-15

19

United States Extreme Record Temperatures and Differences Map  

NSDL National Science Digital Library

This map of the United States shows statewide extremes in temperature, expressed as the difference between record high and low temperature (in degrees Fahrenheit) for each state. It is accompanied by two tables that show record high and low temperatures for each state, along with date, city, and elevation for the location where the measurement was made. Temperature data is in both Fahrenheit and Centigrade degrees.

20

Minimum Temperatures, Diurnal Temperature Ranges, and Temperature Inversions in Limestone Sinkholes of Different Sizes and Shapes  

Microsoft Academic Search

Air temperature data from five enclosed limestone sinkholes of various sizes and shapes on the Hetzkogel Plateau near Lunz, Austria (1300 m MSL), have been analyzed to determine the effect of sinkhole geometry on temperature minima, diurnal temperature ranges, temperature inversion strengths, and vertical temperature gradients. Data were analyzed for a non-snow-covered October night and for a snow-covered December night

Charles D. Whiteman; Thomas S. Haiden; Bernhard Pospichal; Stefan Eisenbach; Reinhold Steinacker

2004-01-01

21

Development of Temperature Sensitive Paints for the Detection of Small Temperature Differences  

NASA Technical Reports Server (NTRS)

Temperature sensitive paints (TSP s) have recently been used to detect small temperature differences on aerodynamic model surfaces. These types of applications impose stringent performance requirements on a paint system. The TSP s must operate over a broad temperature range, must be physically robust (cannot chip or peel), must be polishable to at least the smoothness of the model surface, and must have sufficient sensitivity to detect small temperature differences. TSP coatings based on the use of metal complexes in polymer binders were developed at NASA Langley Research Center which meet most of the requirements for detection of small temperature differences under severe environmental conditions.

Oglesby, Donald M.; Upchurch, Billy T.; Sealey, Bradley S.; Leighty, Bradley D.; Burkett, Cecil G., Jr.; Jalali, Amir

1997-01-01

22

Temperature sensitivity of soil respiration in different ecosystems in China  

Microsoft Academic Search

Understanding the sensitivity of soil respiration to temperature change and its impacting factors is an important base for accurately evaluating the response of terrestrial carbon balance to future climatic change, and thus has received much recent attention. In this study, we synthesized 161 field measurement data from 52 published papers to quantify temperature sensitivity of soil respiration in different Chinese

Shushi Peng; Shilong Piao; Tao Wang; Jinyu Sun; Zehao Shen

2009-01-01

23

Population difference thermometry for ultra-low temperatures  

Microsoft Academic Search

We report measurements of the asymmetry of the intensities of the quadrupolar fine structure of NMR lines in ferromagnetic MnSb down to 30 mK. The asymmetry ratios provide a means of measuring the temperature, and is an example of the use of population difference thermometry as a primary thermometer for ultra-low temperatures.

P. M. Andersen; N. S. Sullivan; B. Andraka; J. S. Xia; E. D. Adams

1992-01-01

24

Mechanical behavior at different temperatures and stresses for superelastic nickeltitanium orthodontic wires having different transformation temperatures  

Microsoft Academic Search

Objective: The purpose of this study was to investigate the mechanical properties of superelastic nickeltitanium orthodontic wires under controlled stress and temperature.Methods: Three different superelastic nickeltitanium wires were examined using differential scanning calorimetry (DSC), three-point bending test and micro X-ray diffraction (micro-XRD). The three-point bending test was carried out at constant temperature (23, 37 and 60C) and stepwise temperature changes

M. Iijima; H. Ohno; I. Kawashima; K. Endo; I. Mizoguchi

2002-01-01

25

Temperature Rise during Resin Composite Polymerization under Different Ceramic Restorations  

PubMed Central

Objectives: The purpose of this study was to measure temperature increase induced by various light polymerizing units during resin composite polymerization beneath one of three types of ceramic restorations. Methods: The resin composite (Variolink II) was polymerized between one of three different ceramic specimens (zirconium oxide, lithium disilicate, feldspathic) (diameter 5 mm, height 2 mm) and a dentin disc (diameter 5 mm, height 1 mm) with a conventional halogen light, a high intensity halogen light, or an LED unit. The temperature rise was measured under the dentin disc with a J-type thermocouple wire connected to a data logger. Ten measurements were carried out for each group. The difference between the initial and highest temperature readings was taken and the 10 calculated temperature changes were averaged to determine the mean value in temperature rise. Two way analysis of variance (ANOVA) was used to analyze the data (polymerizing unit, ceramic brand) for significant differences. The Tukey HSD test was used to perform multiple comparisons (?=.05). Results: Temperature rise did not vary significantly depending on the light polymerizing unit used (P=.16), however, the type of ceramic system showed a significant effect on temperature increases (P<.01). There were no statistically significant differences between lithium disilicate and feldspathic ceramic systems (P >.05); in comparison, the resin composite polymerized under the zirconium oxide ceramic system induced a significantly lower temperature increase than the other ceramic systems tested (P<.05) Conclusions: The resin composite polymerized beneath zirconium oxide ceramic system induced significantly smaller temperature changes. The maximal temperature increase detected in all groups in this study was not viewed as critical for pulpal health.

Yondem, Isa; Altintas, Subutay Han; Usumez, Aslihan

2011-01-01

26

Simulation of Soil Temperature Dynamics with Models Using Different Concepts  

PubMed Central

This paper presents two soil temperature models with empirical and mechanistic concepts. At the test site (calcaric arenosol), meteorological parameters as well as soil moisture content and temperature at 5 different depths were measured in an experiment with 8 parcels realizing the combinations of the fertilized, nonfertilized, irrigated, nonirrigated treatments in two replicates. Leaf area dynamics was also monitored. Soil temperature was calculated with the original and a modified version of CERES as well as with the HYDRUS-1D model. The simulated soil temperature values were compared to the observed ones. The vegetation reduced both the average soil temperature and its diurnal amplitude; therefore, considering the leaf area dynamics is important in modeling. The models underestimated the actual soil temperature and overestimated the temperature oscillation within the winter period. All models failed to account for the insulation effect of snow cover. The modified CERES provided explicitly more accurate soil temperature values than the original one. Though HYDRUS-1D provided more accurate soil temperature estimations, its superiority to CERES is not unequivocal as it requires more detailed inputs.

Sandor, Renata; Fodor, Nandor

2012-01-01

27

Analysis of Unsteady Turbulent Merging Jet Flows With Temperature Difference  

SciTech Connect

Suitable turbulence model is required in the course of establishing a proper analysis methodology for thermal stripping phenomena. For this purpose, three different turbulence models of k-e model, modified k-e model, and full Reynolds stress model and VLES are applied to analyze unsteady turbulent flows with temperature variation. Four test cases are selected for verification. These are vertical jet flows with water and sodium, parallel jet flow with sodium, and merging pipe flow through T-junction with sodium. The geometries of test cases well represent common places where thermal stripping might be occurred. The turbulence model computation shows overall jet flow characteristics well and good comparison of mean temperature distribution. Temperature variance (?2) is rather over-predicted, but location of high temperature variance is matched well with that of the large amplitude of temperature variation of experimental results. Meanwhile, mixing of hot and cold jet flow is found to be not that active. (authors)

Geun Jong Yoo; Won Dae Jeon [Changwon National University, 9 Sarim-dong, Changwon, Kyongnam, 641-773 (Korea, Republic of)

2002-07-01

28

Effects of different cooling conditions on twist drill temperature  

Microsoft Academic Search

In the past, many researchers have studied wear developed on drilling tools mainly due to the high temperatures generated\\u000a which accelerate thermally related wear mechanisms and thereby reducing tool life. This paper deals with an experimental investigation\\u000a on the effect of an internal coolant approach (for different air pressure) on drill bit temperature, comparing it with an\\u000a external coolant approach

Eyup Bagci; Babur Ozcelik

2007-01-01

29

Avalanche behavior of power MOSFETs under different temperature conditions  

Microsoft Academic Search

The ability of high-voltage power MOSFETs to withstand avalanche events under different temperature conditions are studied by experiment and two-dimensional device simulation. The experiment is performed to investigate dynamic avalanche failure behavior of the domestic power MOSFETs which can occur at the rated maximum operation temperature range (-55 to 150 C). An advanced ISE TCAD two-dimensional mixed mode simulator with

Lu Jiang; Wang Lixin; Lu Shuojin; Wang Xuesheng; Han Zhengsheng

2011-01-01

30

Sensitivity of Satellite Multichannel Sea Surface Temperature Retrievals to the Air-Sea Temperature Difference  

NASA Astrophysics Data System (ADS)

The advanced very high resolution radiometer multichannel sea surface temperature (MCSST) retrieval technique provides global algorithm accuracy statistics generally showing a bias of less than 0.1C and an rms error of less than 0.7C when compared to colocated drifting buoy in situ data in the absence of aerosols. This remaining error is not always random but is shown to be correlated to the air-sea temperature difference. The MCSST technique is modeled and then compared to in situ data to show this dependency. Atmospheric radiative transfer calculations are used to provide a simulation of satellite retrieval sensitivity to air-sea temperature differences. Buoy sea surface temperature (SST) and air temperature observations are then presented as experimental verification of the simulation results. Retrieval errors depend both on the mean air-sea temperature difference conditions present in the data set used to empirically derive the algorithm and on the changes in air-sea temperature difference conditions relative to the derivation data set mean conditions. Retrieval error is found to respond linearly with air-sea temperature difference changes. MCSST retrieval errors of 1.0C can occur for air-sea temperature difference changes of 7-10C from mean conditions when the dual-window (channels 3 and 4) or triple-window (channels 3, 4, and 5) algorithms are used. The split-window (channels 4 and 5) MCSST algorithm is shown to be less sensitive to air-sea temperature differences. Cross-product SST (CPSST) and nonlinear SST (NLSST) algorithms are also examined. These algorithms generate results similar to the MCSST algorithm for the dual- and triple-window equations. However, the CPSST and NLSST split-window algorithms demonstrate greater sensitivity to air-sea temperature difference changes than do the MCSST split-window algorithm. Retrieval errors of 1C can occur for air-sea temperature difference changes of 10-12C from mean conditions. Users of satellite SST retrievals in regions that experience large fluctuations in air-sea temperature difference should be aware of this possible error source.

May, Douglas A.; Holyer, Ronald J.

1993-07-01

31

Surface flux estimation using radiometric temperature: A dual-temperature-difference method to minimize measurement errors  

NASA Astrophysics Data System (ADS)

Surface temperature serves as a key boundary condition that defines the partitioning of surface radiation into sensible and latent heat fluxes. Surface brightness temperature measurements from satellites offer the unique possibility of mapping surface heat fluxes at regional scales. Because uncertainties in satellite measurements of surface radiometric temperature arise from atmospheric corrections, surface emissivity, and instrument calibrations, a number of studies have found significant discrepancies between modeled and measured heat fluxes when using radiometric temperature. Recent research efforts have overcome these uncertainties and in addition have accounted for the difference between radiometric and aerodynamic temperature by considering soil and vegetative-canopy aerodynamic resistances. The major remaining obstacle to using satellite data for regional heat flux estimation is inadequate density of near-surface air temperature observations. In this paper we describe a simple, operational, double-difference approach for relating surface sensible heat flux to remote observations of surface brightness temperature, vegetative cover and type, and measurements of near-surface wind speed and air temperature from the synoptic weather network. A double difference of the time rate of change in radiometric and air temperature observations is related to heat flux. This double-difference approach reduces both the errors associated with deriving a radiometric temperature and with defining meteorological quantities at large scales. The scheme is simpler than other recent approaches because it requires minimal ground-based data and does not require modeling boundary layer development. The utility of this scheme is tested with ground-based radiometric temperature observations from several arid and subhumid climates with a wide range of vegetative cover and meteorological conditions.

Norman, J. M.; Kustas, W. P.; Prueger, J. H.; Diak, G. R.

2000-08-01

32

Nonlinear Relationship between Level of Blood Flow and Skin Temperature for Different Dynamics of Temperature Change  

PubMed Central

We present a study of the relationship between blood flow and skin temperature under different dynamics of skin-temperature-change: locally induced thermal shock and well controlled, gradual change. First, we demonstrate memory phenomena for blood flow and skin temperature under both conditions. Secondly, we point out that the hysteresis loops obtained are dependent on initial conditions, indicating physiological response times of more than twenty minutes. We also show that under thermal shock the level of blood flow is preserved up to some characteristic temperature limit, independently of subject.

Vuksanovic, Vesna; Sheppard, Lawrence William; Stefanovska, Aneta

2008-01-01

33

Emission Controls Using Different Temperatures of Combustion Air  

PubMed Central

The effort of many manufacturers of heat sources is to achieve the maximum efficiency of energy transformation chemically bound in the fuel to heat. Therefore, it is necessary to streamline the combustion process and minimize the formation of emission during combustion. The paper presents an analysis of the combustion air temperature to the heat performance and emission parameters of burning biomass. In the second part of the paper the impact of different dendromass on formation of emissions in small heat source is evaluated. The measured results show that the regulation of the temperature of the combustion air has an effect on concentration of emissions from the combustion of biomass.

Holubcik, Michal; Papucik, Stefan

2014-01-01

34

Deposition Ice Nuclei Concentration at Different Temperatures and Supersaturations  

NASA Astrophysics Data System (ADS)

Ice formation is one of the main processes involved in the initiation of precipitation. Some aerosols serve to nucleate ice in clouds. They are called ice nuclei (IN) and they are generally solid particles, insoluble in water. At temperatures warmer than about -36C the only means for initiation of the ice phase in the atmosphere involves IN, and temperature and supersaturation required to activate IN are considered as key information for the understanding of primary ice formation in clouds. The objective of this work is to quantify the IN concentration at ground level in Crdoba City, Argentina, under the deposition mode, that is to say that ice deposits on the IN directly from the vapor phase. It happens when the environment is supersaturated with respect to ice and subsaturated with respect to liquid water. Ice nuclei concentrations were measured in a cloud chamber placed in a cold room with temperature control down to -35C. The operating temperature was varied between -15C and -30C. Ice supersaturation was ranged between 2 and 20 %. In order to quantify the number of ice particles produced in each experiment, a dish containing a supercooled solution of cane sugar, water and glycerol was placed on the floor of the cloud chamber. The activated IN grew at the expense of vapor until ice crystals were formed and these then fell down onto the sugar solution. Once there, these crystals could grow enough to be counted easily with a naked eye after a period of about three minutes, when they reach around 2 mm in diameter. In order to compare the present results with previously reported results, the data were grouped in three different ranges of supersaturation: the data with supersaturations between 2 and 8 %, the data with supersaturations between 8 and 14% and the data with supersaturations between 14 and 20 %. In the same way, in order to analize the behavior of IN concentration with supersaturation, the data were grouped for three different temperatures, the data with temperatures between -15C and -20C, the data with temperatures between -20C and -25C and the data with temperatures between -25C and -30C. The results confirm that for each temperature range, the concentration of IN increases at higher supersaturation, and show the tendency of the IN concentration to increase with increasing ice supersaturation. Based on previous parameterizations, a combination of IN concentration in relation with temperature and ice supersaturation is proposed in this work. As far as we know, this is among the first work to measure and parameterize the concentration of deposition ice nuclei in the Southern Hemisphere.

Lpez, M. L.; Avila, E.

2013-05-01

35

MY NASA DATA: Differences Between Ground and Air Temperatures  

NSDL National Science Digital Library

In this data activity, students explore real NASA satellite data to compare the near-surface air temperature and surface temperature in different climate regions, and draw conclusions about the seasonal patterns and the effect of the underlying surface on the air temperature. Step-by-step instructions for use of the MY NASA DATA Live Access Server (LAS) guide students through selecting a data set, importing the data into a spreadsheet, creating graphs, and analyzing data plots. The lesson provides detailed procedures, related links and sample graphs, follow-up questions, extensions, and teacher notes. Designed for student use, MY NASA DATA LAS samples micro datasets from large scientific data archives, and provides structured investigations engaging students in exploration of real data to answer real world questions.

36

Performance of fuel system at different diesel temperature  

NASA Astrophysics Data System (ADS)

This paper presents the findings about performance of the fuel system of a diesel engine at different diesel temperature obtained through simulation and experiment. It can be seen from these findings that at the same rotational speed of fuel pump, the initial pressure in the fuel pipe remain unchanged as the fuel temperature increases, the peak pressure at the side of fuel pipe near the injector delays, and its largest value of pressure decreases. Meanwhile, at the same temperature, as the rotational speed increases, the initial pressure of fuel pipe is also essentially the same, the arrival of its peaks delays, and its largest value of pressure increases. The maximum fuel pressure at the side of fuel pipe near the injector has an increase of 28.9 %, 22.3%, and 13.9% respectively than the previous ones according to its conditions. At the same rotational speed, as the temperature increases, the injection quantity through the nozzle orifice decreases. At the same temperature, as the rotational speed increases, the injection quantity through the nozzle orifice increases. These experimental results are consistent with simulation results.

Xu, Xiaoyong; Li, Xiaolu; Sun, Zai

2010-08-01

37

Comparison of five different interpolation methods for daily temperature  

NASA Astrophysics Data System (ADS)

Investigation on air temperature has been and will be very important in hydrology and other climatological sciences. Air temperature is an important input to a variety of hydrological and ecological models. Since most near-surface air-temperature data are collected at irregularly spaced point locations rather than over continuous surfaces, point-based temperatures must be accurately interpolated over the landscape in order to be useful in practice. In this study, five interpolation techniques are investigated: (1) lapse rate method, (2) ordinary kriging, (3) external drift kriging and (4) ordinary kriging with residuals which are considered as the reference methods to compare the results of a newly developed method, named (5) quantile kriging. The study area is located in South Africa and the data are provided from four different sources with daily resolution of Tmax and Tmin. The interpolation techniques were used to estimate the temperature data for three sets of data and results were compared. It has been found that cross-validation has been improved by eliminating the outliers (dataset B), and furthermore by infilling the missing data by multi linear regression (dataset C). According to the geographical position of the country, a seasonal fluctuation has been further detected in the daily correlation coefficients.

Rabiei, E.; Lebrenz, H.; Brdossy, A.

2012-04-01

38

What is the Difference between Heat and Temperature?  

NSDL National Science Digital Library

In this laboratory activity, learners explore the difference between heat and temperature, and explore the rate of heat transfer from one substance to another as it depends on the density of the substances being investigated. The activity can be conducted either in a science lab or in a kitchen. It is one of two activities supporting the scientific investigation of the Interstellar Medium (ISM), and is linked to reading material, reading review questions and problems, a teacher answer sheet, and glossary.

39

Uncertainties in estimating Normalized Difference Temperature Index from TOA radiances  

NASA Astrophysics Data System (ADS)

The widely used surface temperature/vegetation index (Ts/NDVI) triangle method provides an effective way to estimate surface turbulent energy fluxes and soil moisture. This type of method mainly relies on the Normalized Difference Temperature Index (NDTI), which is usually calculated from land surface temperature (LST). However, retrieval of LST from remote sensing data requires atmospheric correction procedures, which are often difficult and troublesome. Our study investigates the feasibility of determining NDTI using top of the atmosphere (TOA) radiances, instead of satellite-derived LST. A thorough assessment of the uncertainties in NDTI estimates for different atmospheric and surface conditions is performed. It is shown that NDTI can be estimated from TOA radiances with an accuracy of 90% if the spatial variabilities of atmospheric parameters (water vapor, effective atmospheric temperature) and surface emissivity are below 10%, 4 K and 0.05, respectively. A test study is performed using Moderate Resolution Imaging Spectroradiometer (MODIS) data over a heterogeneous area of the Poyang Lake basin of China for six consecutive image acquisitions. When the spatial variations of the surface emissivity, effective atmospheric temperature and water vapor are respectively less than 0.01, 1 K and 0.2 g cm-2, the TOA radiance-calculated NDTI value and LST-determined NDTI value are quite close with root mean square deviation (RMSD) values and biases varying from 0.033 to 0.051 and from -0.004 to 0.014. The high coefficient of determination (R2) values, ranging from 0.904 to 0.939, indicated that the use of TOA radiances appears to be adequate for calculating NDTI in these studies. Overall, the proposed algorithm requires less a prior information on the atmospheric state while providing NDTI estimates at a similar level of accuracy than obtained using atmospherically corrected LST data products. It therefore provides a useful alternative for determining NDTI from satellite data.

peng, jian; liu, yuanbo; loew, alexander

2013-04-01

40

Piglets' Surface Temperature Change at Different Weights at Birth  

PubMed Central

The study was carried out in order to verify the effects of piglets weight at birth on their surface temperature change (ST) after birth, and its relationship with ingestion time of colostrum. Piglets from four different sows were weighed at birth and divided into a totally randomized design with three treatments according to birth weight (PBW): T1 - less than 1.00 kg, T2 - 1.00 to 1.39 kg, and T3 - higher than or equal to 1.40 kg. The time spent for the first colostrum ingestion was recorded (TFS). Images of piglets surface by thermal imaging camera were recorded at birth (STB) and 15, 30, 45, 60, and 120 min after birth. The air temperature and relative humidity were recorded every 30 min and the indexes of temperature and humidity (THI) were calculated. A ST drop after 15 min from birth was observed, increasing again after sixty minutes. Positive correlations were found between the PBW and the ST at 30 and 45 min after birth. The PBW was negatively correlated with the TFS. The THI showed high negative correlations (?0.824 and ?0.815) with STB and after 15 min from birth. The piglets surface temperature at birth was positively correlated with temperature thereof to 15 min, influencing therefore the temperatures in the interval of 45 to 120 min. The birth weight contributes significantly to postnatal hypothermia and consequently to the time it takes for piglets ingest colostrum, requiring special attention to those of low birth weight.

Caldara, Fabiana Ribeiro; dos Santos, Luan Sousa; Machado, Sivanilza Teixeira; Moi, Marta; de Alencar Naas, Irenilza; Foppa, Luciana; Garcia, Rodrigo Garofallo; de Kassia Silva dos Santos, Rita

2014-01-01

41

Piglets' surface temperature change at different weights at birth.  

PubMed

The study was carried out in order to verify the effects of piglets' weight at birth on their surface temperature change (ST) after birth, and its relationship with ingestion time of colostrum. Piglets from four different sows were weighed at birth and divided into a totally randomized design with three treatments according to birth weight (PBW): T1 - less than 1.00 kg, T2 - 1.00 to 1.39 kg, and T3 - higher than or equal to 1.40 kg. The time spent for the first colostrum ingestion was recorded (TFS). Images of piglets' surface by thermal imaging camera were recorded at birth (STB) and 15, 30, 45, 60, and 120 min after birth. The air temperature and relative humidity were recorded every 30 min and the indexes of temperature and humidity (THI) were calculated. A ST drop after 15 min from birth was observed, increasing again after sixty minutes. Positive correlations were found between the PBW and the ST at 30 and 45 min after birth. The PBW was negatively correlated with the TFS. The THI showed high negative correlations (-0.824 and -0.815) with STB and after 15 min from birth. The piglet's surface temperature at birth was positively correlated with temperature thereof to 15 min, influencing therefore the temperatures in the interval of 45 to 120 min. The birth weight contributes significantly to postnatal hypothermia and consequently to the time it takes for piglets ingest colostrum, requiring special attention to those of low birth weight. PMID:25049971

Caldara, Fabiana Ribeiro; Dos Santos, Luan Sousa; Machado, Sivanilza Teixeira; Moi, Marta; de Alencar Ns, Irenilza; Foppa, Luciana; Garcia, Rodrigo Garfallo; de Kssia Silva Dos Santos, Rita

2014-03-01

42

Interhemispheric temperature difference as a predictor of boreal winter ENSO  

NASA Astrophysics Data System (ADS)

We use statistical analysis to show statistically significant relationship between the boreal winter MEI index of ENSO and HadCRUT3 temperature difference between Northern and Southern hemispheres (NH - SH) during the preceding summer. Correlation values increase (in absolute terms) if the correlated time periods are increased from month to seasonal length. For example December and January (DJ) MEI values anticorrelate stronger with the preceding MJJA period than with any of the four months taken separately. We believe this is further evidence that the correlation is caused by a real physical process as increase of the averaging period tends to reduce statistical noise. The motivation for looking for such a relationship comes from review of literature on paleoclimatic ENSO behavior. We have noticed that in many cases relatively cold NH coincided with "strong ENSO" (frequent El Nios), for example the Ice Age periods and Little Ice Age. On the other hand periods of relatively warm NH (the Holocene climate optimum or Medieval Climate Anomaly) are coincident with frequent or even "permanent" La Nias. This relationship suggest the influence of the position of Intertropical Convergence Zone (ITCZ) on the frequency of El Nios. The simplest physical mechanism of the relationship is that the positive (negative) NH-SH temperature difference causes a north (south) shift of ITCZ with a parallel shift of trade wind zones. The North-South orographic difference between the Panama Isthmus and the South America may cause stronger (weaker) trade winds in Eastern Tropical Pacific increasing (decreasing) the thermochemical tilt which, in turn, causes a more negative (positive) ENSO values. Of course this may be only a first approximation of the real mechanism of this "teleconnection". The correlations we have found are not strong even if statistically significant. For example, the MJJA NH-SH temperature vs. DJ MEI correlation has r = -0.28 implying it explains only 8% of boreal winter ENSO variability. In, fact, we did not expect a high value for a phenomenon which is a self-regulated ocean-atmosphere oscillation with timing partly triggered by stochastic atmospheric forcing, especially as we predict ENSO with (semi)global parameters. It is possible that further research may identify smaller regions of both hemispheres which temperature differences explain a larger part of ENSO variability. However in our opinion, the importance of this result is that it may not only improve ENSO prediction but also help in better understanding of ENSO variability in different time scales.

Piskozub, Jacek; Gutowska, Dorota

2013-04-01

43

Chlorella Virus Encoded Deoxyuridine triphosphatases Exhibit different Temperature Optima  

SciTech Connect

A putative deoxyuridine triphosphatase (dUTPase) gene from chlorella virus PBCV-1 was cloned, and the recombinant protein was expressed in Escherichia coli. The recombinant protein has dUTPase activity and requires Mg{sup 2+} for optimal activity, while it retains some activity in the presence of other divalent cations. Kinetic studies of the enzyme revealed a K{sub m} of 11.7 {mu}M, a turnover k{sub cat} of 6.8 s{sup -1}, and a catalytic efficiency of k{sub cat}/K{sub m} = 5.8 x 105 M{sup -1} s{sup -1}. dUTPase genes were cloned and expressed from two other chlorella viruses IL-3A and SH-6A. The two dUTPases have similar properties to PBCV-1 dUTPase except that IL-3A dUTPase has a lower temperature optimum (37{sup o}C) than PBCV-1 dUTPase (50{sup o}C). The IL-3A dUTPase differs from the PBCV-1 enzyme by nine amino acids, including two amino acid substitutions, Glu81{yields}Ser81 and Thr84{yields}Arg84, in the highly conserved motif III of the proteins. To investigate the difference in temperature optima between the two enzymes, homology modeling and docking simulations were conducted. The results of the simulation and comparisons of amino acid sequence suggest that adjacent amino acids are important in the temperature optima. To confirm this suggestion, three site-directed amino acid substitutions were made in the IL-3A enzyme: Thr84{yields}Arg84, Glu81{yields}Ser81, and Glu81{yields}Ser81 plus Thr84{yields}Arg84. The single substitutions affected the optimal temperature for enzyme activity. The temperature optimum increased from 37 to 55{sup o}C for the enzyme containing the two amino acid substitutions. We postulate that the change in temperature optimum is due to reduction in charge and balkiness in the active cavity that allows more movement of the ligand and protein before the enzyme and substrate complex is formed.

Zhang,Y.; Moriyama, H.; Homma, K.; Van Etten, J.

2005-01-01

44

Evaluation of temperature-selection differences among juvenile muskellunge originating from different latitudes  

Microsoft Academic Search

Genetic differences among muskellunge Esox masquinongy populations are related to residence in major river drainages, suggesting the existence of divergent stocks. By use of radio-telemetry\\u000a we compared different seasonal and diel temperature selection in a southern Illinois reservoir for three geographically and\\u000a genetically distinct stocks of age-2 muskellunge from throughout the latitudinal range of the species. Muskellunge from the\\u000a Upper

Curtis P. Wagner; David H. Wahl

45

Evaluation of temperature-selection differences among juvenile muskellunge originating from different latitudes  

Microsoft Academic Search

Genetic differences among muskellunge Esox masquinongy populations are related to residence in major river drainages, suggesting the existence of divergent stocks. By use of radio-telemetry\\u000a we compared different seasonal and diel temperature selection in a southern Illinois reservoir for three geographically and\\u000a genetically distinct stocks of age-2 muskellunge from throughout the latitudinal range of the species. Muskellunge from the\\u000a Upper

Curtis P. Wagner; David H. Wahl

2007-01-01

46

High-operating temperature MWIR photon detectors based on Type II InAs/GaSb superlattice  

NASA Astrophysics Data System (ADS)

Recent efforts have been paid to elevate the operating temperature of Type II superlattice Mid Infrared photon detectors. Using M-structure superlattice, novel device architectures have been developed, resulting in significant improvement of the device performances. In this paper, we will compare different photodetector architectures and discuss the optimization scheme which leads to almost one order of magnitude of improvement to the electrical performance. At 150K, single element detectors exhibit a quantum efficiency above 50%, and a specific detectivity of 1.05x1012 cm.Hz1/2/W. BLIP operation with a 300K background and 2? FOV can be reached with an operating temperature up to 180K. High quality focal plane arrays were demonstrated with a noise equivalent temperature difference (NEDT) of 11mK up to 120K. Human body imaging is achieved at 150K with NEDT of 150mK.

Razeghi, Manijeh; Pour, Siamak A.; Huang, Edward; Chen, Guanxi; Haddadi, Abbas; Nguyen, Binh-Minh

2011-05-01

47

Global differences between skin and bulk sea surface temperatures  

NASA Astrophysics Data System (ADS)

Infrared satellite imagery provides one of the best means of mapping changes in global sea surface temperature (SST). A series of workshops [Hilland et al., 1985], held to compare the various methods of remotely sensing SST, concluded that of the presently available systems, the Advanced Very High Resolution Radiometer (AVHRR), carried on National Oceanic and Atmospheric Administration (NOAA) polar-orbiting weather satellites, yielded the smallest rms error when compared with ship and buoy in situ data. The widely used Multi Channel SST (MCSST) method, described by McClain et al. [1983], was used to calibrate the AVHRR SST for this workshop intercomparison. This method uses the differences between the radiances of the two AVHRR thermal infrared channels to correct for atmospheric signal attenuation due primarily to water vapor absorption. To provide absolute temperature calibration, the MCSST coefficients are derived by matching the AVHRR observations with simultaneous SSTs measured in situ by freely drifting ocean buoys [McClain et al., 1985]. These drifting buoys typically measure the ocean temperature 0.5-1 m below the sea surface.

Emery, William J.; Schluessel, Peter

48

Thermoelectric properties and efficiency measurements under large temperature differences.  

PubMed

The maximum efficiency of a thermoelectric generator is determined by the material's dimensionless figure of merit ZT. Real thermoelectric material properties are highly temperature dependent and are often measured individually using multiple measurement tools on different samples. As a result, reported ZT values have large uncertainties. In this work we present an experimental technique that eliminates some of these uncertainties. We measure the Seebeck coefficient, electrical conductivity, and thermal conductivity of a single element or leg, as well as the conversion efficiency, under a large temperature difference of 2-160 degrees C. The advantages of this technique include (1) the thermoelectric leg is mounted only once and all measurements are in the same direction and (2) the measured properties are corroborated by efficiency measurements. The directly measured power and efficiency are compared to the values calculated from the measured properties and agree within 0.4% and 2%, respectively. The realistic testing conditions of this technique make it ideal for material characterization prior to implementation in a real thermoelectric generator. PMID:19791947

Muto, A; Kraemer, D; Hao, Q; Ren, Z F; Chen, G

2009-09-01

49

Radiolysis of frozen methane by heavy ions at different temperatures  

NASA Astrophysics Data System (ADS)

Methane ice is found in several bodies of the Solar System, including Titan, interstellar medium and young stellar objects, where it is frequently exposed to cosmic ray and solar wind radiation. The chemical, physical and structural effects induced by fast heavy ion irradiation on methane (CH4) pure ice at different temperatures are analyzed. Experiments were performed in a high-vacuum chamber (P ~ 10-8 mbar) coupled to GANIL accelerator beam lines in France. Ice monitoring during irradiation was done by mid-infrared spectroscopy (FTIR). Irradiation by 6 MeV 16O2+ ion beam on the CH4 pure ice at 15, 25 and 35 K as well as by 220 MeV 16O7+ [1], 267 MeV 56Fe22+ and 606 MeV 70Zn26+ at 15 K were performed. The analysis show that the CH4 destruction rate at 15 K is higher than at 35 K, and that the production rate of new molecules (C2H2, C2H4, C2H6, C3H8, C4H8, C4H10 and radicals CH3 and C2H5) increases as the temperature decreases. These findings should be relevant for the understanding of chemical reactions involving CH4 induced by high energy radiation in the Titans atmosphere. References: [1] de Barros, A. L. F et al. Cosmic ray impact on astrophysical ices: laboratory studies on heavy ion irradiation of methane. A&A, v. 531, p. A160-A169, 2011. [2] M. Garozzo et al. The influence of temperature on the synthesis of molecules on icy grain mantles in dense molecular clouds. A&A v 528, A118 p 9 2011.

Meja, C. F.; Bordalo, V.; de Barros, A. L. F.; Domaracka, A.; Rothard, H.; Boduch, P.; da Silveira, E. F.

2012-04-01

50

Maximum vehicle cabin temperatures under different meteorological conditions.  

PubMed

A variety of studies have documented the dangerously high temperatures that may occur within the passenger compartment (cabin) of cars under clear sky conditions, even at relatively low ambient air temperatures. Our study, however, is the first to examine cabin temperatures under variable weather conditions. It uses a unique maximum vehicle cabin temperature dataset in conjunction with directly comparable ambient air temperature, solar radiation, and cloud cover data collected from April through August 2007 in Athens, GA. Maximum cabin temperatures, ranging from 41-76 degrees C, varied considerably depending on the weather conditions and the time of year. Clear days had the highest cabin temperatures, with average values of 68 degrees C in the summer and 61 degrees C in the spring. Cloudy days in both the spring and summer were on average approximately 10 degrees C cooler. Our findings indicate that even on cloudy days with lower ambient air temperatures, vehicle cabin temperatures may reach deadly levels. Additionally, two predictive models of maximum daily vehicle cabin temperatures were developed using commonly available meteorological data. One model uses maximum ambient air temperature and average daily solar radiation while the other uses cloud cover percentage as a surrogate for solar radiation. From these models, two maximum vehicle cabin temperature indices were developed to assess the level of danger. The models and indices may be useful for forecasting hazardous conditions, promoting public awareness, and to estimate past cabin temperatures for use in forensic analyses. PMID:19234721

Grundstein, Andrew; Meentemeyer, Vernon; Dowd, John

2009-05-01

51

On the bulk-skin temperature difference and its impact on satellite remote sensing of sea surface temperature  

Microsoft Academic Search

Satellite infrared sensors only observe the temperature of the skin of the ocean rather than the bulk sea surface temperature (SST) traditionally measured from ships and buoys. In order to examine the differences and similarities between skin and bulk temperatures, radiometric measurements of skin temperature were made in the North Atlantic Ocean from a research vessel along with coincident measurements

Peter Schluessel; William J. Emery; Hartmut Grassl; Theodor Mammen

1990-01-01

52

Contractions of a human skeletal muscle at different temperatures.  

PubMed Central

1. Influence of temperature on electrically evoked twitch contractions and maximal voluntary contractions was studied in human first dorsal interosseus muscle. The range of the muscle temperature was 35-12 degrees C. 2. The maximal twitch tension decreased by about 50% in cooling from 35-12 degrees C; the tension decrease was more pronounced below 25 degrees C. The temperature coefficients (Q10 values) estimated for muscle temperatures of 35-25 degrees C were 1.43 for time-to-peak and 1.7 for half-time of relaxation. 3. The maximum voluntary tension remained relatively constant on cooling to 25 degrees C but decreased by about 30% on cooling to 12-15 degrees C. The normalized rate of tension rise in voluntary contractions was largely independent of temperature. 4. Results are discussed in relation to previous work on temperature and muscle contraction in humans and in animals.

Ranatunga, K W; Sharpe, B; Turnbull, B

1987-01-01

53

Soil temperature under different surface managements: testing a simulation model  

Microsoft Academic Search

Conservation tillage is known to change the temperature and water content of the soils on which it is practised, largely through its effect upon crop residue cover and consequently upon energy exchange between the atmosphere and the soil surface. If simulation models are to be used to estimate these changes, then the processes by which temperature and water content are

R. F. Grant; R. C. Izaurralde; D. S. Chanasyk

1995-01-01

54

Poplar saplings exposed to recurring temperature shifts of different amplitude exhibit differences in leaf gas exchange and growth despite equal mean temperature  

PubMed Central

Most investigations of plant responses to changes in temperature have focused on a constant increase in mean day/night temperature without considering how differences in temperature cycles can affect physiological processes and growth. To test the effects of changes in growth temperature on foliar carbon balance and plant growth, we repeatedly exposed poplar saplings (Populus deltoides nigra) to temperature cycles consisting of 5 days of a moderate (M, +5 C) or extreme (E, +10 C) increase in temperature followed by 5 days of a moderate (M, ?5 C) or extreme (E, ?10 C) decrease in temperature, with respect to a control treatment (C, 23.4 C). The temperature treatments had the same mean temperature over each warm and cool cycle and over the entire study. Our goal was to examine the influence of recurring temperature shifts on growth. Net photosynthesis (A) was relatively insensitive to changes in growth temperature (from 20 to 35 C), suggesting a broad range of optimum temperature for photosynthesis. Leaf respiration (R) exhibited substantial acclimation to temperature, having nearly the same rate at 13 C as at 33 C. There was no evidence that preconditioning through temperature cycles affected the response of A or R to treatment temperature fluctuations. Averaged across the complete warm/cool temperature cycle, the A : R ratio did not differ among the temperature treatments. While foliar carbon balance was not affected, the temperature treatments significantly affected growth. Whole-plant biomass was 1.5 times greater in the M treatment relative to the C treatment. Carbon allocation was also affected with shoot volume and biomass greater in the M and E treatments than in the C treatment. Our findings indicate that temperature fluctuations can have important effects on growth, though there were few effects on leaf gas exchange, and can help explain differences in growth that are not correlated with mean growth temperature.

Cerasoli, Sofia; Wertin, Timothy; McGuire, Mary Anne; Rodrigues, Ana; Aubrey, Doug P.; Pereira, Joao Santos; Teskey, Robert O.

2014-01-01

55

Poplar saplings exposed to recurring temperature shifts of different amplitude exhibit differences in leaf gas exchange and growth despite equal mean temperature.  

PubMed

Most investigations of plant responses to changes in temperature have focused on a constant increase in mean day/night temperature without considering how differences in temperature cycles can affect physiological processes and growth. To test the effects of changes in growth temperature on foliar carbon balance and plant growth, we repeatedly exposed poplar saplings (Populus deltoides nigra) to temperature cycles consisting of 5 days of a moderate (M, +5 C) or extreme (E, +10 C) increase in temperature followed by 5 days of a moderate (M, -5 C) or extreme (E, -10 C) decrease in temperature, with respect to a control treatment (C, 23.4 C). The temperature treatments had the same mean temperature over each warm and cool cycle and over the entire study. Our goal was to examine the influence of recurring temperature shifts on growth. Net photosynthesis (A) was relatively insensitive to changes in growth temperature (from 20 to 35 C), suggesting a broad range of optimum temperature for photosynthesis. Leaf respiration (R) exhibited substantial acclimation to temperature, having nearly the same rate at 13 C as at 33 C. There was no evidence that preconditioning through temperature cycles affected the response of A or R to treatment temperature fluctuations. Averaged across the complete warm/cool temperature cycle, the A : R ratio did not differ among the temperature treatments. While foliar carbon balance was not affected, the temperature treatments significantly affected growth. Whole-plant biomass was 1.5 times greater in the M treatment relative to the C treatment. Carbon allocation was also affected with shoot volume and biomass greater in the M and E treatments than in the C treatment. Our findings indicate that temperature fluctuations can have important effects on growth, though there were few effects on leaf gas exchange, and can help explain differences in growth that are not correlated with mean growth temperature. PMID:24876300

Cerasoli, Sofia; Wertin, Timothy; McGuire, Mary Anne; Rodrigues, Ana; Aubrey, Doug P; Pereira, Joo Santos; Teskey, Robert O

2014-01-01

56

Cure rate of Halthane 73-18 at different temperatures  

Microsoft Academic Search

Halthane 73-18 is a new polyurethane type adhesive being developed for an assembly operation. This report includes the cure rate at ambient, 38, 78, and 100 C. An equation relating cure rate, time, and temperature is established.

P. A. Foster; R. W. Ashcraft

1977-01-01

57

Age Differences in the Associations between Felt Temperatures and Color Choices  

ERIC Educational Resources Information Center

The present study was designed to explore age differences in the association of temperatures with specific colors, using as stimuli actual felt temperatures rather than the 'imagined' or ambient temperatures used in other studies. (Author)

Morgan, George A.; And Others

1975-01-01

58

Karyotyping of Saccharomyces strains with different temperature profiles.  

PubMed

This study examined the karyotype, the fermentation performance and the optimum growth temperature (Topt) of 28 yeast strains all identified as species belonging to Saccharomyces sensu stricto. The strains were isolated from fermented musts, which had not been inoculated, at two temperature ranges: 20-40 degrees C and approximately 0-6 degrees C. The results demonstrated a correlation between the Topt and the chromosome organization. In particular, strains with Topt of less than 30 degrees C showed only two bands in the region between 365 and 225 kb, while those with a Topt greater than 30 degrees C had three bands in this size range. From a taxonomic viewpoint, the Topt is a better indicator for the Saccharomyces sp. than the ceiling temperature of 37 degrees C currently used to differentiate cryotolerant Saccharomyces bayanus and S. pastorianus from non-cryotolerant S. cerevisiae and S. paradoxus strains. PMID:9674135

Giudici, P; Caggia, C; Pulvirenti, A; Rainieri, S

1998-05-01

59

[Fluoride emission from different soil minerals at high temperatures].  

PubMed

The emission characteristics of fluoride pollutants from montmorillonite, kaolinite, vermiculite, geothite and allophane were studied to elucidate the mechanism of fluoride-releasing from soils during brick and tile making at high temperatures from 300 degrees C to 1000 degrees C. The rate of fluoride emission varied with temperature, mineral type, heating time, specific surface area and cations added to minerals. The escape of crystalline water resulting from crystal lattice collapse at a certain high temperature was found to affect the rate of fluoride emission. Calcium compounds could decrease fluoride emission rate from montmorillonite. At 800 degrees C, the rate of fluoride emission from Ca-treated montmorillonite decreased by 59.6% compared to untreated montmorillonite. The order for fluoride-fixing capacity of the 5 calcium compounds at 800 degrees C was as follows: CaCO3 > CaO > Ca3(PO4)2 > Ca(OH)2 > CaSO4. PMID:11432054

Wu, W; Xie, Z; Xu, J; Liu, C

2001-03-01

60

Developmental time of Blattisocius tarsalis (Acari: Ascidae) at different temperatures.  

PubMed

The developmental time of the predatory mite Blattisocius tarsalis (Berlese) (Acari: Ascidae) was investigated at temperatures of 15, 21 and 25 degrees C and 75% r.h. Eggs 1-3 days old of Ephestia kuehniella Zeller (Lep.: Pyralidae), killed by freezing, were used as food. Mean developmental times were found to be 22.4, 8.5 and 7.0 days, respectively. Within the investigated thermal limits the developmental rate showed a linear relationship with temperature and the corresponding thermal threshold for development was calculated to 10.2 degrees C. PMID:11989484

Nielsen, P S

2001-01-01

61

Gender Differences in Finger Temperatures During Cold Air Exposure.  

National Technical Information Service (NTIS)

Many women are involved in activities that impose a risk of cold injury to the fingers, and the ability of women to resist these effects is unknown. The purpose of this study was to compare finger temperatures of women and men exposed to 0 deg C air for u...

J. E. Reading D. E. Roberts W. K. Prusaczyk

1997-01-01

62

Cure Rate of Halthane 73-19 at Different Temperatures.  

National Technical Information Service (NTIS)

Halthane 73-19 is a new polyurethane type adhesive. The report includes the cure rate at ambient, 38, 78, and 100 C. The cure rate of 73-19 is significantly faster than that of Halthane 73-18 at temperatures up to 78 C. (ERA citation 04:027277)

P. A. Foster

1979-01-01

63

Cure rate of Halthane 73-19 at different temperatures  

Microsoft Academic Search

Halthane 73-19 is a new polyurethane type adhesive. The report includes the cure rate at ambient, 38, 78, and 100 C. The cure rate of 73-19 is significantly faster than that of Halthane 73-18 at temperatures up to 78 C.

1979-01-01

64

Sodium incorporation strategies for CIGS growth at different temperatures  

Microsoft Academic Search

Incorporation of sodium into Cu(In,Ga)Se2 (CIGS) absorber layers and low-temperature absorber growth processes are important issues for the processing of flexible CIGS solar cells, particularly when polymer substrates are used. Na present during growth of CIGS is known to influence the growth kinetics and to lead to structurally and electronically modified absorber material. With post-deposition Na incorporation, predominantly electronic properties

D. Rudmann; D. Bremaud; A. F. da Cunha; G. Bilger; A. Strohm; M. Kaelin; H. Zogg; A. N. Tiwari

2005-01-01

65

Mixed solar wind originating from coronal regions of different temperatures  

NASA Technical Reports Server (NTRS)

Ionization states of elements in the solar wind are often used to determine thermal gradients in the lower corona. This method is based on the assumption, that in the beginning, solar wind material has a homogeneous temperature determining the original charge state of elements. Features in M/Q-spectra which might appear if the above assumption is violated are investigated and compared with observational evidence.

Bochsler, P.

1983-01-01

66

Shelf life of herring (Clupea harengus) kept at different temperatures  

Microsoft Academic Search

The objective of this project was to learn about the main types of evaluation of quality of fish, and quality changes during different storage condition. Atlantic herring (Clupea harengues) was chosen as a similar fish species to mackerel, the important fish species in Cape Verde. Herring was stored in ice and kept for 9 days, at +1, 5C and -1,

Gospa Jurisic David; Hannes Magnusson; Heida Palmadottir

67

Type-II InAs/GaSb photodiodes and focal plane arrays aimed at high operating temperatures  

NASA Astrophysics Data System (ADS)

Recent efforts to improve the performance of type II InAs/GaSb superlattice photodiodes and focal plane arrays (FPA) have been reviewed. The theoretical bandstructure models have been discussed first. A review of recent developments in growth and characterization techniques is given. The efforts to improve the performance of MWIR photodiodes and focal plane arrays (FPAs) have been reviewed and the latest results have been reported. It is shown that these improvements has resulted in background limited performance (BLIP) of single element photodiodes up to 180 K. FPA shows a constant noise equivalent temperature difference (NEDT) of 11 mK up to 120 K and it shows human body imaging up to 170 K.

Razeghi, M.; Abdollahi Pour, S.; Huang, E. K.; Chen, G.; Haddadi, A.; Nguyen, B. M.

2011-09-01

68

The response of high-temperature optical fiber sensor applied to different materials  

NASA Astrophysics Data System (ADS)

This paper mainly studies the response of high-temperature optical fiber sensor applied to different hot structural materials. Strain and temperature sensitivities of the optical fiber are discussed. The heat test on the bare FBG shows that wavelength and temperature are not of a simple linear relationship, and that using a quadratic function description is more reasonable at high temperature. A type of silica optical fiber sensor is attached to different structures using a special high-temperature adhesive. Two kinds of high-temperature materials, high-temperature alloy and ultra-high temperature ceramic, are used as the base materials. Experiments are carried out to break through the connection technology at high temperature. The response of temperature and strain are measured simultaneously from room temperature to maximum 750C. The response differences are compared by using the signal decoupling method. The relationship between wavelength change and structural thermal strain is studied; the first-order and the second-order temperature sensitivities coefficients are given for different materials. Through the experiment, the different strain transfer coefficients are given in the two cases. This study realized the concurrent monitoring of structural temperature and strain at high-temperature situation using only one sensor, and thus provides a new way for hot structure health monitoring in high-temperature environment.

Du, Chong; Xie, Weihua; Huo, Shiyu; Meng, Songhe; Xu, Kai; Jiao, Lichuang

2013-08-01

69

Trench-parallel fluid flow in subduction zones resulting from temperature differences  

Microsoft Academic Search

Differences in the thermal state of subducting crust along the trench of a subduction zone cause differences in subduction zone temperature that persist to tens of kilometers down-dip of the trench. The resulting differences in fluid viscosity, permeability, and hydraulic conductivity can lead to trench-parallel variations in fluid pressure on the plate boundary fault. Temperature differences in locations with low

Glenn A. Spinelli; Demian M. Saffer

2007-01-01

70

Physicochemical characteristics of palm oil and sunflower oil blends fractionated at different temperatures  

Microsoft Academic Search

This research was carried out to determine the effect of fractionation temperature on the physicochemical characteristics of refined, bleached and deodorized (RBD) palm oil and sunflower oil blends fractionated at different temperatures. Blends of 20% and 40% sunflower oil with 80% and 60% RBD palm oil, respectively, were fractionated at three different temperatures (15, 18 and 21 C). The results

Hasmadi Mamat; I. Nor Aini; Mamot Said; Radzuan Jamaludin

2005-01-01

71

Experiment and Simulation Study on the Creep Behavior of PMMA at Different Temperatures  

Microsoft Academic Search

In the present study, creep experiments at different stress and different temperatures were carried out to study the creep behavior of PMMA (MDYB-3). The results show that the creep behavior of PMMA is significantly dependent on temperature in the temperature range of 2075C. It was indicated that the duration curves of creep could be divided into three phases. The Chen

Z. Z. Gao; W. Liu; Z. Q. Liu; Z. F. Yue

2010-01-01

72

FEM prediction of the pseudoelastic behavior of NiTi SMA at different temperatures with one temperature testing results  

Microsoft Academic Search

In this paper, a finite element method (FEM) has been applied to predict the pseudoelastic behavior of NiTi shape memory alloys at different temperatures with only one temperature testing results. A three-dimensional micromechanical model has been developed based on Gall and Lims expression for Gibbs free energy. The difference of elastic properties between austenite and martensite are taken into consideration.

X. M. Wang; Z. F. Yue

2007-01-01

73

Viability of microencapsulated probiotic lactobacilli during storage at different temperatures.  

PubMed

The aim of this study was to develop technological and microbiological basics for the use of microencapsulated probiotics in meat products. Probiotic Lactobacillus (L.) reuteri, L. rhamnosus, L. paracasei and L. gasseri strains were chosen for potential use in meat products. The effects of spices and NaCI on the microbiological stability were investigated in pilot studies. Lyophilised samples were stored for 6 months withoud additives. Microencapsulation was done with water-soluble and water-insoluble coatings. Samples were stored at 2 degrees C and 20 degrees C for six months in gelatine solutions: without additives, with 5% NaCI, with 10% cloves and with 10% black pepper. Spices and salt exhibited a strong inhibitive effect on the bacterial counts of the tested strains. During storage the lyophilised probiotic strains were stable at 2 degrees C and at 20 degrees C. Protective effects of the microencapsulation however were heterogenous. Although at the beginning protective effects against the antimicrobial activity of cloves were shown for L. rhamnosus, none of the tested coatings were able to protect durably. L. paracasei proved to be very stable in general. The use of probiotic lactobacilli strains in meat products seems possible as protective effects of the microencapsulation were recognised. However, these effects must be tested for each specific application, e.g. strain/additive combination, due to individual strain differences. PMID:23367663

Jhne, Julia; Bonaparte, Christine; Khne, Michael; Klein, Gnter

2013-01-01

74

Biodegradability of dispersed crude oil at two different temperatures.  

PubMed

Laboratory experiments were initiated to study the biodegradability of oil after dispersants were applied. Two experiments were conducted, one at 20 degrees C and the other at 5 degrees C. In both experiments, only the dispersed oil fraction was investigated. Each experiment required treatment flasks containing 3.5% artificial seawater and crude oil previously dispersed by either Corexit 9500 or JD2000 at a dispersant-to-oil ratio of 1:25. Two different concentrations of dispersed oil were prepared, the dispersed oil then transferred to shake flasks, which were inoculated with a bacterial culture and shaken on a rotary shaker at 200 rpm for several weeks. Periodically, triplicate flasks were removed and sacrificed to determine the residual oil concentration remaining at that time. Oil compositional analysis was performed by gas chromatography/mass spectrometry (GC/MS) to quantify the biodegradability. Dispersed oil biodegraded rapidly at 20 degrees C and less rapidly at 5 degrees C, in line with the hypothesis that the ultimate fate of dispersed oil in the sea is rapid loss by biodegradation. PMID:17316707

Venosa, A D; Holder, E L

2007-05-01

75

A novel method to evaluate the applicability of time temperature integrators to different temperature profiles  

Microsoft Academic Search

The use of a Peltier device to provide controlled heating and cooling profiles to test the applicability of time temperature integrators (TTIs) has been evaluated. The ?-amylase of Bacillus amyloliquefaciens has been used as a case study.Kinetic parameters of the enzyme were first determined as D85C of 6.1min0.4min and z of 12C1.3C. Non-isothermal heat treatment processes were simulated with a

K. Mehauden; P. W. Cox; S. Bakalis; M. J. H. Simmons; G. S. Tucker; P. J. Fryer

2007-01-01

76

XRD study of the grain growth in CdTe films annealed at different temperatures  

Microsoft Academic Search

The CdTe thin films electrodeposited on stainless steel substrates were annealed in air at various temperatures and time durations in order to investigate the influence of post-deposition heat treatments on the grain growth of the films. The recrystallization process at lower annealing temperature is different from that of the high-temperature annealing. The annealing at lower temperature promotes better grain growth

Joel Pantoja Enr??quez; Xavier Mathew

2004-01-01

77

The effect of rearing in different temperature regimes on the reproduction of Anagasta kuehniella (Lepidoptera: Pyralidae).  

PubMed

Eggs of Anagasta kuehniella (Zeller) are widely used in mass rearing of parasitoids, especially Trichogramma spp. and predators in many biological-control programs. The objective of this study was to improve the efficiency of mass rearing of A. kuehniella through determining the optimal temperature conditions for rearing, by assessing the effect of temperature during the developmental stages on the reproduction of A. kuehniella. We evaluated 1) the effect of temperature at which A. kuehniella was kept from egg to adult death, on reproduction; 2) the effect of temperature during the larval and pupal stages on oviposition; and 3) the effect of different temperatures on adults that originated from larvae kept in a constant temperature of 25C. The results indicated that the optimal temperature range for the development of A. kuehniella is between 20-30C, as at 30C there was a marked decrease in viability of the egg and larval stages. The best temperature for maintaining A. kuehniella from egg to adult death is 25C. Temperatures of 30 and 32C lead to deformations in genitalia of males, reducing the viability of eggs, and also eggs and females from these temperatures have lower weights. The rearing temperature of immatures affects the egg-laying capacity of adults and the egg viability. The oviposition capacity of adults kept in different temperatures ranging from 18 to 32C, after being reared in constant temperature (25C) during the larval stages, was not affected. PMID:23905744

Coelho, A; Parra, J R P

2013-08-01

78

Temperature characteristics of silicon avalanche photodiodes  

NASA Astrophysics Data System (ADS)

The paper presents the results of studies on temperature dependence of such parameters as a dark current, noise current, gain, noise equivalent power and detectivity of silicon epiplanar avalanche photodiodes at the ITE. The photodiode reach-through structure is of an nPLU-p-(pi) - p+ type with an under-contact ring and a channel stopper. The temperature range was stretching from -40 C to +40 C. Specially developed for this purpose an automatic system for low noise measurements was used. A two- stage micro-cooler with a Peltier's element was applied to control and stabilize the temperature of measured structures.

Wegrzecka, Iwona; Grynglas, Maria; Wegrzecki, Maciej; Bar, Jan; Grodecki, Remigiusz

2001-08-01

79

Evaluation of temperature differences for paired stations of the U.S. Climate Reference Network  

USGS Publications Warehouse

Adjustments to data observed at pairs of climate stations have been recommended to remove the biases introduced by differences between the stations in time of observation, temperature instrumentatios, latitude, and elevation. A new network of climate stations, located in rural settings, permits comparisons of temperatures for several pairs of stations without two of the biases (time of observation and instrurtientation). The daily, monthly, and annual minimum, maximum, and mean temperatures were compared for five pairs of stations included in the U.S. Climate Reference Network. Significant differences were found between the paired stations in the annual minimum, maximum, and mean temperatures for all five pairs of stations. Adjustments for latitude and elevation differences contributed to greater differences in mean annual temperature for four of the five stations. Lapse rates computed from the mean annual temperature differences between station pairs differed from a constant value, whether or not latitude adjustments were made to the data. The results suggest that microclimate influences on temperatures observed at nearby (horizontally and vertically) stations are potentially much greater than influences that might be due to latitude or elevation differences between the stations. ?? 2005 American Meteorological Society.

Gallo, K. P.

2005-01-01

80

Clinical review: Brain-body temperature differences in adults with severe traumatic brain injury.  

PubMed

Surrogate or 'proxy' measures of brain temperature are used in the routine management of patients with brain damage. The prevailing view is that the brain is 'hotter' than the body. The polarity and magnitude of temperature differences between brain and body, however, remains unclear after severe traumatic brain injury (TBI). The focus of this systematic review is on the adult patient admitted to intensive/neurocritical care with a diagnosis of severe TBI (Glasgow Coma Scale score of less than 8). The review considered studies that measured brain temperature and core body temperature. Articles published in English from the years 1980 to 2012 were searched in databases, CINAHL, PubMed, Scopus, Web of Science, Science Direct, Ovid SP, Mednar and ProQuest Dissertations & Theses Database. For the review, publications of randomised controlled trials, non-randomised controlled trials, before and after studies, cohort studies, case-control studies and descriptive studies were considered for inclusion. Of 2,391 records identified via the search strategies, 37 were retrieved for detailed examination (including two via hand searching). Fifteen were reviewed and assessed for methodological quality. Eleven studies were included in the systematic review providing 15 brain-core body temperature comparisons. The direction of mean brain-body temperature differences was positive (brain higher than body temperature) and negative (brain lower than body temperature). Hypothermia is associated with large brain-body temperature differences. Brain temperature cannot be predicted reliably from core body temperature. Concurrent monitoring of brain and body temperature is recommended in patients where risk of temperature-related neuronal damage is a cause for clinical concern and when deliberate induction of below-normal body temperature is instituted. PMID:23680353

Childs, Charmaine; Lunn, Kueh Wern

2013-04-22

81

Each to their own: skeletal muscles of different function use different biochemical strategies during aestivation at high temperature.  

PubMed

Preservation of muscle morphology depends on a continuing regulatory balance between molecules that protect and molecules that damage muscle structural integrity. Excessive disruption of the biochemical balance that favours reactive oxygen species (ROS) in disused muscles may lead to oxidative stress, which in turn is associated with increased atrophic or apoptotic signalling and/or oxidative damage to the muscle and thus muscle disuse atrophy. Increases in the rate of oxygen consumption likely increase the overall generation of ROS in vivo. Temperature-induced increases in oxygen consumption rate occur in some muscles of ectotherms undergoing prolonged muscular disuse during aestivation. In the green-striped burrowing frog, Cyclorana alboguttata, both large jumping and small non-jumping muscles undergo atrophy seemingly commensurate with their rate of oxygen consumption during aestivation. However, because the extent of atrophy in these muscles is not enhanced at higher temperatures, despite a temperature-sensitive rate of oxygen consumption in the jumping muscle, we proposed that muscles are protected by biochemical means that, when mobilised at higher temperatures, inhibit atrophy. We proposed that the biochemical response to temperature would be muscle-specific. We examined the effect of temperature on the antioxidant and heat shock protein systems and determined the extent of oxidative damage to lipids and proteins in two functionally different skeletal muscles, the gastrocnemius (jumping muscle) and the iliofibularis (non-jumping muscle), by aestivating frogs at 24 and 30C for 6 months. We assayed small molecule antioxidant capacity, mitochondrial and cytosolic superoxide dismutase activities and Hsp70 concentrations to show that protective mechanisms in disused muscles are differentially regulated with respect to both temperature and aestivation. High aestivation temperature results in an antioxidant response in the metabolically temperature-sensitive jumping muscle. We assayed lipid peroxidation and protein oxidation to show that oxidative damage is apparent during aestivation and its pattern is muscle-specific, but unaffected by temperature. Consideration is given to how the complex responses of muscle biochemistry inform the different strategies muscles may use in regulating their oxidative environment during extended disuse and disuse at high temperature. PMID:23197095

Young, Karen M; Cramp, Rebecca L; Franklin, Craig E

2013-03-15

82

Long-range memory in Earth surface temperatures: spatial scale dependence and land-sea differences  

NASA Astrophysics Data System (ADS)

We present a study of how the long-range memory in temperature time series on scales from months to decades varies between land and sea, and with different degrees of spatial averaging. Earlier analyses suggest that sea temperatures are more persistent than land temperatures, and that global temperatures are more persistent than regional temperatures. As a measure of the long-range memory we estimate the Hurst exponent H by parametric as well as non-parametric methods, and by performing spatial averaging of global gridded temperatures we make a systematic investigation of how the Hurst exponent varies on different spatial scales and between ocean/coastal and continental interior data records. Increasing spatial scale from local records up to the global scale implies that for these data aggregation of relatively weakly persistent records produce records with strong long-range persistence (H?1). We propose some statistical models that may give rise to this phenomenon and discuss their physical relevance.

Fredriksen, Hege-Beate; Rypdal, Kristoffer; Rypdal, Martin

2013-04-01

83

Salt uptake and water loss in hams with different water contents at the lean surface and at different salting temperatures.  

PubMed

The salt uptake homogeneity is crucial in assuring quality in dry-cured hams. The aim of this study was to evaluate the effect of the water contents at the lean surface before salting and of the temperature during salting on the salt uptake. Pieces of loin stored at 3C for 3 days before salting absorbed less salt through a surface that has been dried during storage. A group of raw hams were subjected to different pre-salting storage times (0, 3 and 6 days) and another group subjected to different set room temperatures during salting (-1.0, 0.5 and 4.0C). The duration of storage before salting and the temperature during salting had a negative and a positive effect on the average salt absorption, respectively. The most important effects appeared after 6 days of storage and at 4C. No significant differences in salt uptake homogeneity were found between storage times and between salting temperatures. PMID:23896138

Garcia-Gil, Nria; Muoz, Israel; Santos-Garcs, Eva; Arnau, Jacint; Gou, Pere

2014-01-01

84

Measurement of surface temperature and emissivity of different materials by two-colour pyrometry  

NASA Astrophysics Data System (ADS)

An experimental investigation is performed to substantiate the capability of a charge coupled device camera to measure local temperature and emissivity of different materials heated to temperatures above 500 C by two-colour pyrometric technique using colorimetric method. Materials investigated are Inconel 718 with pyromark (high temperature paint), Inconel 718, stainless steel SS 304 and SS 316. Centerline temperature and emissivity distribution is obtained for target plates maintained at constant temperature by AC heating while complete temperature and emissivity distribution is provided for plates heated by flame impingement. The obtained results are compared with a calibrated infrared camera and thermocouples and the temperature distribution is found to be in close agreement. These results pertain to partially oxidized metal alloys covered in this study. Deviation in the measurement of emissivity can be attributed to its dependence on wavelength range, oxidation, and sensitivity of the image detector.

Raj, Vinay C.; Prabhu, S. V.

2013-12-01

85

Measurement of surface temperature and emissivity of different materials by two-colour pyrometry.  

PubMed

An experimental investigation is performed to substantiate the capability of a charge coupled device camera to measure local temperature and emissivity of different materials heated to temperatures above 500 C by two-colour pyrometric technique using colorimetric method. Materials investigated are Inconel 718 with pyromark (high temperature paint), Inconel 718, stainless steel SS 304 and SS 316. Centerline temperature and emissivity distribution is obtained for target plates maintained at constant temperature by AC heating while complete temperature and emissivity distribution is provided for plates heated by flame impingement. The obtained results are compared with a calibrated infrared camera and thermocouples and the temperature distribution is found to be in close agreement. These results pertain to partially oxidized metal alloys covered in this study. Deviation in the measurement of emissivity can be attributed to its dependence on wavelength range, oxidation, and sensitivity of the image detector. PMID:24387454

Raj, Vinay C; Prabhu, S V

2013-12-01

86

Estimation of Sea Surface Temperatures From Two Infrared Window Measurements With Different Absorption  

Microsoft Academic Search

Radiances measured at two different wavelengths or angles, with a resulting difference in absorption, can t>e used to determine the atmospheric attenuation of the surface radiance so that sea surface temperatures can be derived. Previous investigations used a correction equal to a constant times the difference in measured radiances. Some of these investigations were based on radiances calculated from models

Larry M. McMillin

1975-01-01

87

Sorption isotherms and glass transition temperatures of fish protein hydrolysates with different degrees of hydrolysis  

Microsoft Academic Search

The objective of this research was the determination of the sorption isotherms and glass transition temperatures of five protein hydrolysates with different degrees of hydrolysis (DH). The hydrolysates were obtained by proteolysis of concentrated myofibrillar proteins obtained from Nile tilapia (Oreochromus niloticus) using the enzyme Flavourzyme. There was no significant difference between the different isotherms. Agglomeration and\\/or compactation was observed

D. C. P. Jardim; L. M. B. Candido; F. M. Netto

1999-01-01

88

Antioxidant and oxidative stress responses of sojourners at high altitude in different climatic temperatures  

Microsoft Academic Search

High altitude (HA) is a multi-stressor environment comprising hypobaric hypoxia and cold. Climatic temperature varies with seasonal variation at HA. The present study was undertaken to investigate the effect of ambient temperature on antioxidant profile among sojourners at HA. The study was conducted on sojourners exposed to an altitude of 4,560 m in two different seasons and categorized into two

Sanchari Sinha; Som Nath Singh; Mantu Saha; T. C. Kain; A. K. Tyagi; Uday Sankar Ray

2010-01-01

89

Properties of indium tin oxide films prepared by rf reactive magnetron sputtering at different substrate temperature  

Microsoft Academic Search

Indium tin oxide (ITO) films were deposited onto the glass substrates at different substrate temperatures (RT-500C) by rf reactive magnetron sputtering method. The structural, optical and electrical properties of ITO films have been characterized by X-ray diffraction, scanning electron microscopy, optical transmittance and reflectance, sheet resistance and electrical resistivity measurements. The films deposited at low substrate temperature have a very

Li-jian Meng; M. P dos Santos

1998-01-01

90

Air Pollution, Temperature, and Regional Differences in Lung Cancer Mortality in Japan  

Microsoft Academic Search

In this study, the authors investigated regional differences in lung cancer mortality in Japan, and, based on data acquired between 1970 and 1990 for 47 Japanese prefectures, estimated the relationship between regional lung cancer mortality and air pollution and\\/or temperature. Investigators used data for nitrogen dioxide, sulfur dioxide, motor vehicle density, tobacco expenditure, and temperature as independent variables for age-adjusted

Kwang-Soo Choi; Shoichi Inoue; Reiko Shinozaki

1997-01-01

91

Predicting Shelf Life and Quality of Raspberries Under Different Storage Temperatures  

Microsoft Academic Search

Red raspberries (Rubus idaeus 'Killarney') were harvested twice at the full ripe stage and held for 7 days at 0, 5, 10, 15, or 20 C. The objectives of this work were 1) to obtain quality curves for raspberries stored at different temperatures; 2) to identify, for each temperature, which quality factor(s) limits raspberry marketability; and 3)

M. C. N. Nunes; J. K. Brecht

92

Response to uniaxial load of chemically modified bovine pericardium at different temperatures  

Microsoft Academic Search

Non-destructive uniaxial load tests were performed on glutaraldehyde-fixed bovine pericardium at two different temperatures. Samples were tested first in isotonic saline at room temperature and then stored overnight in buffered glutaraldehyde. This allowed the tissue to recover from the test. The following day after all memory of the previous test had faded, the procedure was repeated on the same samples

C. E. Crofts; E. A. Trowbridge

1988-01-01

93

Statistical Difference in the Normal Phase of the Dipolar Ultracold Gases at Finite Temperatures  

Microsoft Academic Search

We study the equilibrium properties of dipolar Bose and Fermi gases at finite temperatures. We have recently developed a variational ansatz for the phase-space distribution function of a dipolar Fermi gas at finite temperatures. We extend the variational formalism to a Bose gas and discuss the effect of dipolar interactions with different statistics on thermal equilibrium, with particular emphasis on

Yuki Endo; Takahiko Miyakawa; Tetsuro Nikuni

2011-01-01

94

Wire drawing at elevated temperatures using different die materials and lubricants  

Microsoft Academic Search

By increasing the working temperature in a metal-forming operation, the flow stress of the material can be reduced considerably. This paper describes an experimental programme of wire drawing using different lubricants and dies at temperatures varying from ambient to 800C. Dies made from tungsten carbide, HSS and maraging steel were used. An attempt at making Silicon Nitride dies was unsuccessful.

Michael T. Hillery; Vincent J. McCabe

1995-01-01

95

Photosynthetic responses of cassava cultivars (Manihot esculenta Crantz) from different habitats to temperature.  

PubMed

Maximum photosynthetic CO2 exchange rates (Pn) of single attached leaves were determined for several cassava cultivars selected from different habitats and grown in pots outdoors at CIAT, Colombia, S.A. Pn rates were in a narrow range of 22 to 26 ?mol CO2 m(-2)s(-1) for all cultivars tested when measured at high photon flux density, normal air, optimum temperature and with low leaf-air vapor pressure differences. For all tested cultivars (9 cvs.), there was a broad optimum temperature for Pn between 25 to 35C. At temperatures below and above this range Pn declined in all cultivars with Pn rates reaching 80% of maximum at 20 and 40C. Pn temperature coefficient (Q10) from 15-25C was 1.60.2 across cultivars. No consistent relation existed between Pn, optimum temperature, and the original habitat. PMID:24458700

El-Sharkawy, M A; Cock, J H; Held, A A

1984-09-01

96

Preparation of thermosensitive microgels via suspension polymerization using different temperature protocols.  

PubMed

A thermosensitive and biodegradable microgel for protein drug release was synthesized from a thermosensitive macromer via inverse suspension polymerization. Preparation was made under a constant temperature or under variable temperatures. In the latter protocol, dispersion was performed at a low temperature below lower critical solution temperature of the macromer aqueous solution and polymerization was performed at a high temperature above lower critical solution temperature. According to the experiments, the constant-temperature method was not suitable for preparation of microgels when the macromer concentration was high, because early physical gelation at the preparation temperature seriously influenced formation of dispersed droplets. If the macromer concentration was low, both temperature protocols resulted in spherical hydrogel microparticles, but the properties of the resulting microgels were different to a certain degree. In both cases, the model protein bovine serum albumin was loaded into microgels by a postfabrication encapsulation technique, which takes advantage of the microgels' negative thermosensitivity. The results demonstrate that, in microgel preparation, the variable-temperature protocol is useful in suspension polymerization of negatively thermosensitive macromers at a wide rage of monomer concentrations. PMID:16082695

Zhang, Ying; Zhu, Wen; Ding, Jiandong

2005-11-01

97

Alteration of protein patterns in black rock inhabiting fungi as a response to different temperatures.  

PubMed

Rock inhabiting fungi are among the most stress tolerant organisms on Earth. They are able to cope with different stressors determined by the typical conditions of bare rocks in hot and cold extreme environments. In this study first results of a system biological approach based on two-dimensional protein profiles are presented. Protein patterns of extremotolerant black fungi -Coniosporium perforans, Exophiala jeanselmei - and of the extremophilic fungus -Friedmanniomyces endolithicus - were compared with the cosmopolitan and mesophilic hyphomycete Penicillium chrysogenum in order to follow and determine changes in the expression pattern under different temperatures. The 2D protein gels indicated a temperature dependent qualitative change in all the tested strains. Whereas the reference strain P. chrysogenum expressed the highest number of proteins at 40C, thus exhibiting real signs of temperature induced reaction, black fungi, when exposed to temperatures far above their growth optimum, decreased the number of proteins indicating a down-regulation of their metabolism. Temperature of 1C led to an increased number of proteins in all of the analysed strains, with the exception of P. chrysogenum. These first results on temperature dependent reactions in rock inhabiting black fungi indicate a rather different strategy to cope with non-optimal temperature than in the mesophilic hyphomycete P.chrysogenum. PMID:22862921

Tesei, Donatella; Marzban, Gorji; Zakharova, Kristina; Isola, Daniela; Selbmann, Laura; Sterflinger, Katja

2012-08-01

98

Biochemical and growth acclimation of birch to night temperatures: genotypic similarities and differences.  

PubMed

The responses of plants to environmental factors are connected to the time of day. In this study, silver birch (Betula pendula) was grown in growth chambers at five different night temperatures (6-22?C), using gradual changes during the evening and morning hours. Despite the increased night respiration and unaffected daytime net photosynthesis (per square metre), the carbon uptake (biomass) of birch did not decrease, probably due to enhanced biochemical processes on warmer nights and the advantage of higher temperatures during the evening and morning hours. The plant stem height, internode length, stem dry weight (DW), stem mass fraction and specific leaf area increased with warmer night temperatures. Changes in growth and metabolite concentrations were partly nonlinear along the temperature gradient. Thus, the temperature effect depends on the temperature window considered. Genotypes had both common and genotype-specific biochemical responses to night temperatures. The common responses among genotypes were related to growth responses, whereas the unique responses may indicate genotype-specific differences in acclimation. The differences in genotypic growth and metabolite levels are valuable for assessing genotype qualities and understanding the connections between the metabolome and growth. PMID:22612878

Menp, M; Ossipov, V; Kontunen-Soppela, S; Keinnen, M; Rousi, M; Oksanen, E

2013-01-01

99

Alteration of protein patterns in black rock inhabiting fungi as a response to different temperatures  

PubMed Central

Rock inhabiting fungi are among the most stress tolerant organisms on Earth. They are able to cope with different stressors determined by the typical conditions of bare rocks in hot and cold extreme environments. In this study first results of a system biological approach based on two-dimensional protein profiles are presented. Protein patterns of extremotolerant black fungi Coniosporium perforans, Exophiala jeanselmei and of the extremophilic fungus Friedmanniomyces endolithicus were compared with the cosmopolitan and mesophilic hyphomycete Penicillium chrysogenum in order to follow and determine changes in the expression pattern under different temperatures. The 2D protein gels indicated a temperature dependent qualitative change in all the tested strains. Whereas the reference strain P. chrysogenum expressed the highest number of proteins at 40C, thus exhibiting real signs of temperature induced reaction, black fungi, when exposed to temperatures far above their growth optimum, decreased the number of proteins indicating a down-regulation of their metabolism. Temperature of 1C led to an increased number of proteins in all of the analysed strains, with the exception of P. chrysogenum. These first results on temperature dependent reactions in rock inhabiting black fungi indicate a rather different strategy to cope with non-optimal temperature than in the mesophilic hyphomycete P.chrysogenum.

Tesei, Donatella; Marzban, Gorji; Zakharova, Kristina; Isola, Daniela; Selbmann, Laura; Sterflinger, Katja

2012-01-01

100

Temperature Dependence of the Elastic Compliance of Polyethylenes with Different Molecular Structure  

NASA Astrophysics Data System (ADS)

The steady-state recoverable shear compliance, Je0, of commercial linear and long-chain-branched metallocene LLDPE and LDPE was measured at temperatures between 130 C and 190 C. For the linear material and the LDPE containing tree-like branches no distinct temperature dependence of Je0 was found. However, a decrease in Je0 with increasing temperature was observed for the long-chain branched LLDPE (star-like branching topography). This temperature dependence of Je0 can be explained by the analysis of the temperature dependent shape of the relaxation spectra calculated. For the linear-mLLDPE the shape of the spectra is the same for all temperatures leading to thermorheological simplicity and a constant Je0. The spectra of the LDPE are identical in shape in the terminal regime but differ at high relaxation strengths. Thus, a constant Je0 results but also a slight thermorheological complexity in the rubbery plateau. The long-chain branched mLLDPE clearly reveals different temperature dependencies within various parts of the spectra. By this finding the temperature dependence of Je0 can be explained.

Resch, Julia A.; Kaschta, Joachim; Stadler, Florian J.; Muenstedt, Helmut

2008-07-01

101

Egg incubation temperature differently affects female and male hatching dynamics and larval fitness in a leafhopper  

PubMed Central

Temperature effects on ectotherms are widely studied particularly in insects. However, the life-history effects of temperature experienced during a window of embryonic development, that is egg stage, have rarely been considered. We simulated fluctuating temperatures and examined how this affects the operational sex ratio (OSR) of hatching as well as nymph and adult fitness in a leafhopper, Scaphoideus titanus. Specifically, after a warm or cold incubation we compared males and females hatching dynamics with their consequences on the sex ratio in the course of time, body size, weight, and developmental rate of the two populations, all reared on the same posthatching temperature. Males and females eggs respond differently, with females more sensitive to variation in incubation temperature. The different responses of both sexes have consequences on the sex ratio dynamic of hatchings with a weaker protandry after warm incubation. Temperatures experienced by eggs have more complex consequences on posthatching development. Later nymphal instars that hatched from eggs exposed to warm temperature were larger and bigger but developmental rate of the two populations was not affected. Our study demonstrates how incubation temperature could affect operational sex ratio and posthatching development in an insect and how this may be critical for population growth.

Chuche, Julien; Thiery, Denis

2012-01-01

102

An Ultra-Low Noise Superconducting Antenna-Coupled Microbolometer With a Room-Temperature Read-Out  

Microsoft Academic Search

In this letter, we report the electrical and optical characteristics of a superconducting vacuum-bridge microbolometer with an electrical noise equivalent power of 26fW radicHz and an effective time constant of 380 ns, when operated at a bath temperature of 4K. We employ a novel room temperature external negative feedback readout architecture, that allows for noise matching to the device without

Arttu Luukanen; Erich N. Grossman; Aaron J. Miller; P. Helisto; J. S. Penttila; H. Sipola; H. Seppa

2006-01-01

103

Determination of the Effusivity of Different Scratched Coaxial Temperature Sensors Under Hypersonic Flow  

Microsoft Academic Search

This paper presents an experimental method for determining the effusivity values of different scratched coaxial temperature\\u000a sensors. These sensors have a response time on the order of microseconds (50?s) with a rise time of less than 0.3?s. Two\\u000a types of scratch were used, mainly abrasive papers with different grit sizes and scalpel blades with different thicknesses\\u000a to form the sensor

H. A. Mohammed; H. Salleh; M. Z. Yusoff

2010-01-01

104

Viscoelasticity and texture of spreadable cheeses with different fat contents at refrigeration and room temperatures.  

PubMed

The effect of the 2 common consumption temperatures, refrigeration temperature (10C) and room temperature (22C), on the viscoelasticity, mechanical properties, and perceived texture of commercial cream cheeses was studied. Two samples with different fat contents, regular and low fat, from each of 4 selected commercial brands were analyzed. The selection criteria were based on identification of brands with different percentages of fat content reduction between the regular- and low-fat samples (35, 50, 84, and 98.5%). The fat content of regular-fat samples ranged from 19.8 to 26.0% (wt/wt), and that of low-fat samples ranged from 0.3 to 13.0% (wt/wt). Viscoelasticity was measured in a controlled-stress rheometer using parallel-plate geometry, and the mechanical characteristics of samples were measured using the spreadability test. Differences in the intensity of thickness, creaminess, and roughness between the regular- and low-fat samples of each commercial brand were evaluated at each of the selected temperatures by using the paired comparisons test. At 10C, all samples showed higher viscoelastic modulus values, firmness, and stickiness, and lower spreadability than when they were measured at 22C. Differences in viscoelasticity and mechanical properties between each pair of samples of the same brand were greater at 10C than at 22C because of the influence not only of fat content but also of fat state. Ingestion temperature did not modify the sensory differences detected between each pair of samples in terms of creaminess and roughness, but it did modify the differences detected in thickness. The joint consideration of sample composition, fat state, and product behavior during oral processing could explain the differences detected in thickness perceived because of measurement temperatures. PMID:22999281

Bayarri, S; Carbonell, I; Costell, E

2012-12-01

105

Antioxidant and oxidative stress responses of sojourners at high altitude in different climatic temperatures  

Microsoft Academic Search

High altitude (HA) is a multi-stressor environment comprising hypobaric hypoxia and cold. Climatic temperature varies with\\u000a seasonal variation at HA. The present study was undertaken to investigate the effect of ambient temperature on antioxidant\\u000a profile among sojourners at HA. The study was conducted on sojourners exposed to an altitude of 4,560m in two different seasons\\u000a and categorized into two groups

Sanchari Sinha; Som Nath Singh; Mantu Saha; T. C. Kain; A. K. Tyagi; Uday Sankar Ray

2010-01-01

106

Genetic differences influencing behavioral temperature regulation in small mammals. II. Genotype-environment interactions  

Microsoft Academic Search

The importance of genotype by temperature interactions contributing to individual differences in nesting behavior has been demonstrated using two inbred strains ofMus musculus. Exposure to low ambient temperature increased amounts of cotton used by both the high-nesting (BALB\\/cJ) and low-nesting (C57BL\\/6J) strains. The larger total nesting scores of BALB\\/cJ mice compared to those of C57BL\\/6J mice resulted from differential increases,

Carol Becker Lynch; Joseph P. Hegmann

1973-01-01

107

An investigation of thick-film resistor, fired at different temperatures, for strain sensors  

Microsoft Academic Search

Some commercial 10 k?\\/sq. thick-film resistors based on RuO 2, ruthenates or a mixture of RuO2 and ruthenates, were evaluated for strain gauge applications. The resistors were fired at different temperatures to determine the influence of firing temperature on the electrical characteristics. The conductive phase in the resistors was determined with X-ray powder-diffraction (XRD) analysis. Microstructures of the thick-film resistors

Mako Hrovat; Darko Belavic; Zoran Samardzija; Janez Holc

2001-01-01

108

Lipase-catalyzed interesterification in packed bed reactor using 2 different temperatures.  

PubMed

Lipase-catalyzed interesterification of high oleic sunflower oil and fully hydrogenated soybean oil (70 : 30, wt/ wt) was carried out in a packed bed reactor using an immobilized lipase from Thermomyces lanuginosus (Lipozyme TL IM) and the effect of a stepwise temperature protocol involving the 2 different temperatures, 60 and 70 C, was investigated. The melting point of a fat that was incubated at 70 C for 9 min was 57 C, which suggested that it should be to employ a lower reaction temperature of 60 C, after the first 9 min of the reaction. There were no significant differences (P < 0.05) in the conversion degree, triacylglycerol profile, and solid fat content between a constant temperature protocol (70 C) and a stepwise temperature protocol (a combination of 70 and 60 C). After 50 cycles, the overall residual activities of enzymes employed in stepwise temperature protocol were significantly (P < 0.05) higher than those of enzymes employed in constant temperature protocol. PMID:22417335

Chae, Mi-Hwa; Park, Hye-Kyung; Kwon, Kwang-Il; Kim, Jong-Wook; Hong, Seung In; Kim, Yangha; Kim, Byung Hee; Kim, In-Hwan

2011-05-01

109

Temperature measurements with two different IR sensors in a continuous-flow microwave heated system  

PubMed Central

Summary In a continuous-flow system equipped with a nonresonant microwave applicator we have investigated how to best assess the actual temperature of microwave heated organic solvents with different characteristics. This is non-trivial as the electromagnetic field will influence most traditional methods of temperature measurement. Thus, we used a microwave transparent fiber optic probe, capable of measuring the temperature inside the reactor, and investigated two different IR sensors as non-contact alternatives to the internal probe. IR sensor 1 measures the temperature on the outside of the reactor whilst IR sensor 2 is designed to measure the temperature of the fluid through the borosilicate glass that constitutes the reactor wall. We have also, in addition to the characterization of the before mentioned IR sensors, developed statistical models to correlate the IR sensor reading to a correct value of the inner temperature (as determined by the internal fiber optic probe), thereby providing a non-contact, indirect, temperature assessment of the heated solvent. The accuracy achieved with these models lie well within the range desired for most synthetic chemistry applications.

Rydfjord, Jonas; Svensson, Fredrik; Fagrell, Magnus; Savmarker, Jonas; Thulin, Mans

2013-01-01

110

Temperature influences on water permeability and chlorpyrifos uptake in aquatic insects with differing respiratory strategies  

USGS Publications Warehouse

Aquatic insects have evolved diverse respiratory strategies that range from breathing atmospheric air to breathing dissolved oxygen. These strategies result in vast morphological differences among taxa in terms of exchange epithelial surface areas that are in direct contact with the surrounding water that, in turn, affect physiological processes. This paper examines the effects of acute temperature shifts on water permeability and chlorpyrifos uptake in aquatic insects with different respiratory strategies. While considerable differences existed in water permeability among the species tested, acute temperature shifts raised water influx rates similarly in air-breathing and gill-bearing taxa. This contrasts significantly with temperature-shift effects on chlorpyrifos uptake. Temperature shifts of 4.5??C increased 14C-chlorpyrifos accumulation rates in the gill-bearing mayfly Cinygma sp. and in the air-breathing hemipteran Sigara washingtonensis. However, the temperature-induced increase in 14C-chlorpyrifos uptake after 8 h of exposure was 2.75-fold higher in Cinygma than in Sigara. Uptake of 14C-chlorpyrifos was uniformly higher in Cinygma than in Sigara in all experiments. These findings suggest that organisms with relatively large exchange epithelial surface areas are potentially more vulnerable to both osmoregulatory distress as well as contaminant accumulation. Temperature increases appear more likely to impact organisms that have relatively large exchange epithelial surface areas, both as an individual stressor and in combination with additional stressors such as contaminants.

Buchwalter, D. B.; Jenkins, J. J.; Curtis, L. R.

2003-01-01

111

Comparison of viability and heat resistance of Clostridium sporogenes stored at different temperatures.  

PubMed

The objective of this study was to determine the influence of storage temperature on the viability and heat resistance of Clostridium sporogenes spores. Spore suspension containing both spores and vegetative cells was divided into 3 groups to be stored at different temperatures of -20 (freezing), 4 (refrigerating), and 25 degrees C (ambient temperature). Samples stored for different times within the 2 mo were tested for viability by comparison of colony counts on plates and for heat resistance by determining D values at 121 degrees C. No significant differences were found in the viability of vegetative cells during the storage period, regardless of storage temperatures tested, while the viability of the spores stored for more than 4 wk was significantly higher at 4 degrees C than at -20 degrees C. The heat resistance of spores stored at 4 degrees C for more than 4 wk was remarkably higher than that at 25 degrees C, but similar to that at -20 degrees C throughout the storage period. Consequently, it turned out that a refrigerating temperature of 4 degrees C is satisfactory for storage of C. sporogenes spores in maintaining viability and heat resistance. This study suggests that storage temperature influences the viability and heat resistance of C. sporogenes spores. PMID:19200102

Mah, J-H; Kang, D-H; Tang, J

2009-01-01

112

Genetically determined differences in ethanol sensitivity influenced by body temperature during intoxication  

SciTech Connect

The present study investigated the importance of body temperature during intoxication in mediating differences between five inbred strains of mice (C57BL/6J; BALB/cJ; DBA/2J; A/HeJ; 129/J) in their acute sensitivity to the hypnotic effects of ethanol. Mice exposed to 22/degrees/C after ethanol injection became hypothermic and exhibited statistically significant differences between strains in rectal temperatures at the return of the righting reflex (RORR), duration of loss of the righting reflex (LORR), and blood and brain ethanol concentrations at RORR. Exposure to 34/degrees/C after injection offset ethanol-hypothermia and markedly reduced strain-related differences in rectal temperatures and blood and brain ethanol concentrations at RORR. Brain ethanol concentrations at RORR were significantly lower in C57, BALB, DBA and A/He mice exposed to 34/degrees/C compared to mice exposed to 22/degrees/C during intoxication suggesting that offsetting hypothermia increased ethanol sensitivity in these strains. Taken with previous in vitro studies, these results suggest that genetically determined differences in acute sensitivity to the behavioral effects of ethanol reflect differences in body temperature during intoxication as well as differences in sensitivity to the initial actions of ethanol at the cellular level.

Alkana, R.L.; Finn, D.A.; Bejanian, M.; Crabbe, J.C.

1988-01-01

113

Rheological characterization of novel physically crosslinked terpolymeric hydrogels at different temperatures  

NASA Astrophysics Data System (ADS)

The main objective of this research work is to reveal the detailed and extensive rheological characterization of terpolymeric hydrogel formulations using a variety of monomers having different concentrations of acrylic acid and applying a range of temperatures. The hydrogels with the different concentrations of acrylic acid were prepared in the absence of air using three different monomers, by free radical polymerization, gradually increasing the temperature up to polymerization point, using ethyl alcohol as solvent. Different shear measurements were performed to study rheological properties, temperature dependence, and yield strength of acrylic acid pharmaceutical hydrogels. Various models were applied to analyze the rheological behavior of the gels. The acrylic acid pharmaceutical gels having physical cross links in the gel networks, exhibit remarkable temperature dependence especially with relatively higher concentration of acrylic acid at greater shear rate. Flow curves plotted at various temperatures indicate that these gels exhibit a reasonable pseudoplastic behavior. All these hydrogels require appropriate yield strength to break their network structures. The gel samples exhibit the best fit to the Modified Bingham model, which can explain the overall flow behavior of these topical gels. The rheological analysis indicates that these gels may be used as topical gels for targeted and controlled drug delivery at a specific site.

Malana, Muhammad Aslam; Zohra, Rubab; Khan, Muhammad Saleem

2012-09-01

114

Implant Surface Temperature Changes during Er:YAG Laser Irradiation with Different Cooling Systems  

PubMed Central

Objective: Peri-implantitis is one of the most common reasons for implant failure. Decontamination of infected implant surfaces can be achieved effectively by laser irradiation; although the associated thermal rise may cause irreversible bone damage and lead to implant loss. Temperature increments of over 10C during laser application may suffice for irreversible bone damage. Purpose of Study: The purpose of this study was to evaluate the temperature increment of implant surface during Er:YAG laser irradiation with different cooling systems. Materials and Methods: Three implants were placed in a resected block of sheep mandible and irradiated with Er:YAG laser with 3 different cooling systems namely water and air spray, air spray alone and no water or air spray. Temperature changes of the implant surface were monitored during laser irradiation with a K-type thermocouple at the apical area of the fixture. Results: In all 3 groups, the maximum temperature rise was lower than 10C. Temperature changes were significantly different with different cooling systems used (P<0.001). Conclusion: Based on the results, no thermal damage was observed during implant surface decontamination by Er:YAG laser with and without refrigeration. Thus, Er:YAG laser irradiation can be a safe method for treatment of periimplantitis.

Monzavi, Abbas; Shahabi, Sima; Fekrazad, Reza; Behruzi, Roohollah; Chiniforush, Nasim

2014-01-01

115

Interval finite difference method for steady-state temperature field prediction with interval parameters  

NASA Astrophysics Data System (ADS)

A new numerical technique named interval finite difference method is proposed for the steady-state temperature field prediction with uncertainties in both physical parameters and boundary conditions. Interval variables are used to quantitatively describe the uncertain parameters with limited information. Based on different Taylor and Neumann series, two kinds of parameter perturbation methods are presented to approximately yield the ranges of the uncertain temperature field. By comparing the results with traditional Monte Carlo simulation, a numerical example is given to demonstrate the feasibility and effectiveness of the proposed method for solving steady-state heat conduction problem with uncertain-but-bounded parameters. [Figure not available: see fulltext.

Wang, Chong; Qiu, Zhi-Ping

2014-04-01

116

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

PubMed

Non-linear propagation of ultrasound can lead to increased heat generation in medical diagnostic imaging due to the preferential absorption of harmonics of the original frequency. A numerical model has been developed and tested that is capable of predicting the temperature rise due to a high amplitude ultrasound field. The acoustic field is modelled using a numerical solution to the Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation, known as the Bergen Code, which is implemented in cylindrical symmetric form. A finite difference representation of the thermal equations is used to calculate the resulting temperature rises. The model allows for the inclusion of a number of layers of tissue with different acoustic and thermal properties and accounts for the effects of non-linear propagation, direct heating by the transducer, thermal diffusion and perfusion in different tissues. The effect of temperature-dependent skin perfusion and variation in background temperature between the skin and deeper layers of the body are included. The model has been tested against analytic solutions for simple configurations and then used to estimate temperature rises in realistic obstetric situations. A pulsed 3 MHz transducer operating with an average acoustic power of 200 mW leads to a maximum steady state temperature rise inside the foetus of 1.25 degrees C compared with a 0.6 degree C rise for the same transmitted power under linear propagation conditions. The largest temperature rise occurs at the skin surface, with the temperature rise at the foetus limited to less than 2 degrees C for the range of conditions considered. PMID:10829673

Divall, S A; Humphrey, V F

2000-03-01

117

Temperature  

NSDL National Science Digital Library

This topic in depth begins with the About Temperature (1) Web site, written by Beverly T. Lynds of Unidata, which is a program that works to enable university researchers and educators to acquire and use atmospheric and related data. The one-page site explains what temperature is, the development of thermometers, heat and thermodynamics, and other related topics. The second site is maintained by the University of Execter's Centre for Innovation in Mathematics Teaching. Actually an online tool called Conversion Calculator for Units of Temperature (2), the site allows users to type in any value, choose a significant figure, press "convert it," and get that value in Kelvin, Celsius, Fahrenheit, r'aumur, and rankine units. The next site is a lesson plan from AskEric.com entitled Temperature: Is it Hot or Cold? (3). Written for 2nd graders, the lesson demonstrates to how to read thermometers, determine their rise or fall, record temperatures, and take temperatures of various items. The fourth site, Surface Temperature Analysis (4), is presented by NASA's Goddard Institute for Space Studies. Here, visitors can view graphs, maps, animations, and station data of global surface temperatures. For example, the animation covers 12-month means from 1971 to 1999. The History Behind the Thermometer (5) Web site, from About.com, explores what a thermometer is, how it works, and how it came into being. The sixth site, entitled Science Shack (6) and offered by the BBC, answers the question, Why do we have two different temperature scales, Celsius and Fahrenheit? The site explains how to create your own thermometer like Galileo's, tells how it works, and why we use other types today. The next site is provided by National Oceanic and Atmospheric Administration (NOAA) and presents US State temperature extremes and drought information (7). Visitors can see all-time temperature maximums and minimums by state, monthly temperatures by state, and more. The last site is an all-inclusive temperature site called Temperature World (8). Everything from news, science, organizations, general interest, games, and more -- all related to temperature -- can be found here.

Brieske, Joel A.

2002-01-01

118

Phase-difference and spectroscopic imaging for monitoring of human brain temperature during cooling.  

PubMed

Decrease of the human brain temperature was induced by intranasal cooling. The main purpose of this study was to compare the two magnetic resonance methods for monitoring brain temperature changes during cooling: phase-difference and magnetic resonance spectroscopic imaging (MRSI) with high spatial resolution. Ten healthy volunteers were measured. Selective brain cooling was performed through nasal cavities using saline-cooled balloon catheters. MRSI was based on a radiofrequency spoiled gradient echo sequence. The spectral information was encoded by incrementing the echo time of the subsequent eight image records. Reconstructed voxel size was 115 mm(3). Relative brain temperature was computed from the positions of water spectral lines. Phase maps were obtained from the first image record of the MRSI sequence. Mild hypothermia was achieved in 15-20 min. Mean brain temperature reduction varied in the interval <-3.0; -0.6>C and <-2.7; -0.7>C as measured by the MRSI and phase-difference methods, respectively. Very good correlation was found in all locations between the temperatures measured by both techniques except in the frontal lobe. Measurements in the transversal slices were more robust to the movement artifacts than those in the sagittal planes. Good agreement was found between the MRSI and phase-difference techniques. PMID:22819582

Weis, Jan; Covaciu, Lucian; Rubertsson, Sten; Allers, Mats; Lunderquist, Anders; Ortiz-Nieto, Francisco; Ahlstrm, Hkan

2012-12-01

119

Temperature-difference-driven mass transfer through the vapor from a cold to a warm liquid.  

PubMed

Irreversible thermodynamics provides interface conditions that yield temperature and chemical potential jumps at phase boundaries. The interfacial jumps allow unexpected transport phenomena, such as the inverted temperature profile [Pao, Phys. Fluids 14, 306 (1971)] and mass transfer from a cold to a warm liquid driven by a temperature difference across the vapor phase [Mills and Phillips, Chem. Phys. Lett. 372, 615 (2002)]. Careful evaluation of the thermodynamic laws has shown [Bedeaux et al., Physica A 169, 263 (1990)] that the inverted temperature profile is observed for processes with a high heat of vaporization. In this paper, we show that cold to warm mass transfer through the vapor from a cold to a warm liquid is only possible when the heat of evaporation is sufficiently small. A necessary criterium for the size of the mass transfer coefficient is given. PMID:23005078

Struchtrup, Henning; Kjelstrup, Signe; Bedeaux, Dick

2012-06-01

120

Statistical Difference in the Normal Phase of the Dipolar Ultracold Gases at Finite Temperatures  

NASA Astrophysics Data System (ADS)

We study the equilibrium properties of dipolar Bose and Fermi gases at finite temperatures. We have recently developed a variational ansatz for the phase-space distribution function of a dipolar Fermi gas at finite temperatures. We extend the variational formalism to a Bose gas and discuss the effect of dipolar interactions with different statistics on thermal equilibrium, with particular emphasis on deformation in momentum space. We examine the stability of the system by varying the temperature, trap aspect ratio, and dipole moment. In addition, we discuss how deformation in both real and momentum spaces can be observed in the high-temperature regime, which is relevant for the current experiments at JILA [Ni et al.: Science 322 (2008) 231] and at the University of Tokyo [Aikawa et al.: New J. Phys. 11 (2009) 055035].

Endo, Yuki; Miyakawa, Takahiko; Nikuni, Tetsuro

2011-04-01

121

The forms of alkalis in the biochar produced from crop residues at different temperatures.  

PubMed

The forms of alkalis of the biochars produced from the straws of canola, corn, soybean and peanut at different temperatures (300, 500 and 700C) were studied by means of oxygen-limited pyrolysis. The alkalinity and pH of the biochars increased with increased pyrolysis temperature. The X-ray diffraction spectra and the content of carbonates of the biochars suggested that carbonates were the major alkaline components in the biochars generated at the high temperature; they were also responsible for the strong buffer plateau-regions on the acid-base titration curves at 500 and 700C. The data of FTIR-PAS and zeta potentials indicated that the functional groups such as -COO(-) (-COOH) and -O(-) (-OH) contained by the biochars contributed greatly to the alkalinity of the biochar samples tested, especially for those generated at the lower temperature. These functional groups were also responsible for the negative charges of the biochars. PMID:21112777

Yuan, Jin-Hua; Xu, Ren-Kou; Zhang, Hong

2011-02-01

122

Analysis of three different junction temperature estimation methods for AC LEDs  

NASA Astrophysics Data System (ADS)

Light-emitting diodes (LEDs) operating on alternating current (AC) are gaining popularity in lighting applications. The junction temperature of an LED significantly influences the performance and reliability of the product. Although there are many proven methods for estimating the junction temperature of direct current (DC) LEDs, only a few methods have been proposed for AC LEDs. Two recently proposed methods, the voltage drop method for AC LEDs and the rms current recovery method, indicated different thermal resistance values for the identical LED package. This discrepancy in thermal resistance values is due to the junction temperature rise in the first half cycle that is not accounted for in the rms current recovery method. The peak emission wavelength shift is another approach used in DC LEDs to estimate junction temperature. This method was used to estimate junction temperature for AC LEDs. The measured junction temperature results were compared to results obtained using the voltage drop method for AC LEDs. The junction temperature estimated using the two approaches agree.

Jayawardena, Asiri; Liu, Yi-wei; Narendran, Nadarajah

2013-08-01

123

Influence of the mode geometry on the strain and temperature sensitivity of different fibers  

NASA Astrophysics Data System (ADS)

Sensitivity of optical fibers to the temperature, longitudinal strain or pressure, is a very important feature in many applications, such as sensors or telecommunication. The most common way to modify (depending on application - either mitigate or strengthen,) this sensitivity is changing the fiber material properties by appropriate glass doping or by employing appropriate microstructure in the fiber. In some cases the precise adjustment of a doping level and sophisticated design of air-holes arrangement is needed to obtain required features of the fiber. In this paper, for the first time, to the best of our knowledge, we report the investigation of the mode area and geometry influence on the fiber temperature and mechanical sensitivities. To do so, we engaged a dedicated all-fiber interferometer which enables the measurement of the temperature and longitudinal strain sensitivities of different fiber types, including conventional and microstructured fibers with different core diameters.

Murawski, M.; Holdynski, Z.; Szymanski, M.; Tenderenda, T.; Ostrowski, L.; ?ukowski, A.; Krisch, H.; Napiera?a, M.; Jaroszewicz, L. R.; Nasilowski, T.

2013-05-01

124

Effects of wearing two different types of clothing on body temperatures during and after exercise  

NASA Astrophysics Data System (ADS)

The experiment was conducted to investigate the human thermoregulatory responses during rest, exercise and recovery at T a 20C and 60% R.H. under the conditions of wearing two different types of clothing. Six healthy men wore two types of clothing: one covering the whole body area except the head (Type A, weight 1656 g), and the other covering only the trunk, upper arms and thighs (Type B, weight 996 g). The level of rectal temperature was kept significantly higher in Type B than in Type A during rest and recovery. The increased and decreased rates of rectal temperature during exercise and recovery were significantly greater in Type A than in Type B, respectively. These findings are discussed from the viewpoint of the differences of skin temperatures of the extremities between Type A and Type B.

Jeong, Woon Seon; Tokura, Hiromi

1989-06-01

125

Difference method for analysing infrared images in pigs with elevated body temperatures.  

PubMed

Infrared imaging proves to be a quick and simple method for measuring temperature distribution on the pig's head. The study showed that infrared imaging and analysis with a difference ROI (region of interest) method may be used for early detection of elevated body temperature in pigs (> 39.5C). A high specificity of approx. 85% and a high sensitivity of 86% existed. The only prerequisite is that there are at least 2 anatomical regions which can be recognised as reproducible in the IR image. Noise suppression is guaranteed by averaging the temperature value within both of these ROI. The subsequent difference imaging extensively reduces the off-set error which varies in every thermal IR-image. PMID:24398117

Siewert, Carsten; Dnicke, Sven; Kersten, Susanne; Brosig, Bianca; Rohweder, Dirk; Beyerbach, Martin; Seifert, Hermann

2014-03-01

126

Eccentric variation of corneal sensitivity to pneumatic stimulation at different temperatures and with CO2.  

PubMed

The purpose was to measure corneal sensitivity at multiple corneal positions using pneumatic stimuli, at room temperature and at ocular surface temperature (with and without CO(2) added), in 15 healthy participants. Sensitivity of central, mid-peripheral, and peripheral cornea was measured using a computer-controlled modified Belmonte esthesiometer to deliver pneumatic cool (air at 20 degrees C), mechanical (air at 50 degrees C), and chemical stimuli (air at 50 degrees C with CO(2) added). The ascending method of limits and method of constant stimuli were adopted to determine the threshold to these stimuli at each location. Sensitivity across the cornea using pneumatic stimuli at different temperatures and chemical stimuli varied only slightly. These patterns of variation are different to what has been previously reported using Cochet-Bonnet esthesiometry. PMID:17662716

Situ, P; Simpson, T L; Fonn, D

2007-09-01

127

Land Surface Temperature Measurements form EOS MODIS Data  

NASA Technical Reports Server (NTRS)

We have developed a physics-based land-surface temperature (LST) algorithm for simultaneously retrieving surface band-averaged emissivities and temperatures from day/night pairs of MODIS (Moderate Resolution Imaging Spectroradiometer) data in seven thermal infrared bands. The set of 14 nonlinear equations in the algorithm is solved with the statistical regression method and the least-squares fit method. This new LST algorithm was tested with simulated MODIS data for 80 sets of band-averaged emissivities calculated from published spectral data of terrestrial materials in wide ranges of atmospheric and surface temperature conditions. Comprehensive sensitivity and error analysis has been made to evaluate the performance of the new LST algorithm and its dependence on variations in surface emissivity and temperature, upon atmospheric conditions, as well as the noise-equivalent temperature difference (NE(Delta)T) and calibration accuracy specifications of the MODIS instrument. In cases with a systematic calibration error of 0.5%, the standard deviations of errors in retrieved surface daytime and nighttime temperatures fall between 0.4-0.5 K over a wide range of surface temperatures for mid-latitude summer conditions. The standard deviations of errors in retrieved emissivities in bands 31 and 32 (in the 10-12.5 micrometer IR spectral window region) are 0.009, and the maximum error in retrieved LST values falls between 2-3 K. Several issues related to the day/night LST algorithm (uncertainties in the day/night registration and in surface emissivity changes caused by dew occurrence, and the cloud cover) have been investigated. The LST algorithms have been validated with MODIS Airborne Simulator (MAS) dada and ground-based measurement data in two field campaigns conducted in Railroad Valley playa, NV in 1995 and 1996. The MODIS LST version 1 software has been delivered.

Wan, Zhengming

1996-01-01

128

Growth characteristics of 28 strains of white tide forming coccolithophorids and elementary analysis under different temperatures  

NASA Astrophysics Data System (ADS)

With the increase of the CO2 concentration in the atmosphere, global warming and acidification of the oceans are troublesome, influencing the marine organisms and the ecosystem. Coccolithophorids are marine unicellular haptophytes producing minute calcareous scales (coccoliths). Because of the conversion of CO2 to CaCO3 and the sedimentation of coccoliths, coccolithophorids are one of the most important organisms participating to the global biogeochemical cycles. Among the coccolithophorids, Gephyrocapsa oceanica and Emiliania huxleyi distribute widely in both oceanic and coastal environments. They often form massive water bloom called white tide and are known to be the major producer of CaCO3 in the present ocean. Moreover, elementary analysis of coccoliths accumulated in sediments provides valuable information on the analysis of paleoenvironment. Although the growth characteristics and calcification properties are important information to estimate their contribution to the global carbon cycle and paleoenvironment, most of the studies have targeted only few strains. Here, we focused on the effect of the temperature on the growth and elementary component of the coccolith for a variety of strains of G. oceanica and E. huxleyi collected from different environments. This approach would clarify the temperature response to various populations and the importance of the use of coccolith as an environmental indicator. 28 strains (20 of G. oceanica, 8 of E. huxleyi) were originally established as cultures or obtained from culture collection. We measured their growth rate from the chlorophyll fluorescence under different temperatures (10, 15, 20, 25, 30C). We also analysed the oxygen isotope ratio, Sr/Ca, U/Ca, Ba/Ca for 5 selected strains with ICP-MS and ICP-AES. In most strains, the optimal growth temperatures were obtained at 20 and 25C, while the growth rates dropped with temperature decrease. No significant differences between the two species were observed. We noted that one Emiliania strain from Bering Sea kept a high growth rate at the lowest temperature (10C) and one Gephyrocapsa strain from tropical sea showed the highest growth at 30C. Locality differences provide more obvious physiological differences than the species differences, suggesting the existence of diverse ecotypes in those cosmopolitan species. The elementary analysis exhibited a high correlation of the cultivation temperatures with the oxygen isotope ratio (R2=0.97) suggesting a high reliability but less correlation of the temperatures with Sr/Ca, U/Ca and Ba/Ca.

Watanabe, Y.; Kawachi, M.; Kawahata, H.

2008-12-01

129

Retrogradation of Amaranth Starch at Different Storage Temperatures and the Effects of Salt and Sugars 1  

Microsoft Academic Search

Cereal Chem. 75(3):308-314 The retrogradation of amaranth, corn, wheat, and rice starches at different storage temperatures (-20, 4, and 25C) was measured by differential scanning calorimetry (DSC). Sodium chloride (2 and 5%), glucose, sucrose, and fructose (10, 20, and 30%) were added to amaranth starch gels. The retrogradation was measured as the percent of gelatinization enthalpy ( ?Hg) of the

L. A. Baker; P. Rayas-Duarte

1998-01-01

130

The mesopic effect of different color temperature LED light sources on road lighting  

Microsoft Academic Search

A equation, Emes = BEp, to deduce from the Ep(photopic illumination) to Emes(mesopic equivalent illumination) is proposed, where B is instant for modified coefficient. The equation is used to calculate the mesopic equivalent illumination of the different color temperature LED light sources under mesopic light levels.

Li Xuan; Shangzhong Jin; Songyuan Cen; Le Wang; Xiaoyan Li

2010-01-01

131

Color gamut variation of LED-lit LCD at different module temperatures  

Microsoft Academic Search

In this paper, we have investigated the color gamut variation of a liquid crystal display (LCD) system with tri-chromatic (red, green and blue) light-emitting diodes (LEDs) as the backlight source at different color and module temperatures. Since the transmission band of a color filter (CF) is broader than those of LEDs, light leakage from the CF results in changes in

Tien-Lung Chiu; Jiun-Haw Lee

2010-01-01

132

Open cycle traveling wave thermoacoustics: Mean temperature difference at the regenerator interface  

Microsoft Academic Search

In an open cycle traveling wave thermoacoustic engine, the hot heat exchanger is replaced by a steady flow of hot gas into the regenerator to provide the thermal energy input to the engine. The steady-state operation of such a device requires that a potentially large mean temperature difference exist between the incoming gas and the solid material at the regenerator's

Nathan T. Weiland; Ben T. Zinn

2003-01-01

133

[Temperature compensation strategy and implementation for photoelectric modulation interferometer with large optical path difference].  

PubMed

For temperature drift in hypervelocity photoelectric modulation interferometer, a control model of temperature compensation is presented including voltage and phase compensation. First, according to the similar and modeling theory, an equivalent circuit model of mechanical properties of hypervelocity photoelectric modulation interferometer was established, the impact of temperature drift on its resonance frequency was analyzed, a mathematical model was set up, which contains drive voltage, frequency and resonance frequency, and the control method was determined for high optical path difference to get steady. Then, a digital method including voltage and phase compensation is given for optical path difference deviation control, which merges the DPLL and program of voltage and phase compensation. Finally, the control method was tested through experiment system. A test between drive control system including voltage and phase compensation and traditional drive control system was executed, using a laser doppler vibrometer to record the amount of change in optical path difference within 3 hours. Results show that the optical path difference deviation caused by temperature drift in long term is reduced by about 50%. PMID:23905367

Wang, Yan-Chao; Wang, Zhi-Bin; Zhang, Ji-Long; Chen, You-Hua

2013-05-01

134

Effect of different downstream temperatures on the performance of a two-layer porous burner  

Microsoft Academic Search

The influence of considering different downstream temperatures on the performance of a two-layer porous burner is studied numerically. A 3D numerical model based on a unit cell was implemented to correctly predict the momentum, heat and mass transfer at the interface of the two layers. Two operating modes are simulated corresponding to the burner radiating to cold and hot environments.

T. C. Hayashi; I. Malico; J. C. F. Pereira

2010-01-01

135

Numerical Study of High-Temperature Air Combustion Using Different Jet Nozzle  

Microsoft Academic Search

High-Temperature Air Combustion (HTAC) is an advanced combustion technology with the advantage of energy saving and low nitrogen oxide pollutant emission. A swirling burner was designed to further improve the HTAC performance and a numerical simulation was carried out based on CFD technology to investigate the combustion process of methane under different jet parameters. The RSM turbulence model was used

Cui-wu Chen; Ya-xin Su; Hao Cheng

2011-01-01

136

Investigation of Heat capacity and Specific Heat: Using Different Temperatures of Water and Solids  

NSDL National Science Digital Library

This activity is a chemistry lab-based investigation where students apply observational skills and critical thinking skills to finding specific heat and heat capacity using different temperatures of water and solids. A final activity will assess students understanding of specific heat and heat capacity and promote data analysis skills, using real-life situations.

137

Evaluation on sperm quality of freshly ejaculated boar semen during in vitro storage under different temperatures  

Microsoft Academic Search

The purpose of this study was to assess the sperm quality of fresh ejaculated boar semen stored under different temperatures for up to 48 h in order to use the fresh semen efficiently. Spermatozoa were evaluated by 4 methods: Using trypan blue staining, the viability of spermatozoa stored at 39, 20, 15 and 4 C for 48 h were 1.6,

Chun-Xia Zou; Zeng-Ming Yang

2000-01-01

138

Open cycle traveling wave thermoacoustics: mean temperature difference at the regenerator interface.  

PubMed

In an open cycle traveling wave thermoacoustic engine, the hot heat exchanger is replaced by a steady flow of hot gas into the regenerator to provide the thermal energy input to the engine. The steady-state operation of such a device requires that a potentially large mean temperature difference exist between the incoming gas and the solid material at the regenerator's hot side, due in part to isentropic gas oscillations in the open space adjacent to the regenerator. The magnitude of this temperature difference will have a significant effect on the efficiencies of these open cycle devices. To help assess the feasibility of such thermoacoustic engines, a numerical model is developed that predicts the dependence of the mean temperature difference upon the important design and operating parameters of the open cycle thermoacoustic engine, including the acoustic pressure, mean mass flow rate, acoustic phase angles, and conductive heat loss. Using this model, it is also shown that the temperature difference at the regenerator interface is approximately proportional to the sum of the acoustic power output and the conductive heat loss at this location. PMID:14650014

Weiland, Nathan T; Zinn, Ben T

2003-11-01

139

Three-dimensional temperature predictions in machining processes using finite difference method  

Microsoft Academic Search

The purpose of this study is to determine the three-dimensional temperature fields on the chip, tool and workpiece during machining, which is one of the most important characteristic of machining processes; since the fields can affect other properties such as residual stresses and tool wear, and thus tool life and fatigue life of finished parts. The finite difference method (FDM)-based

D. Ulutan; I. Lazoglu; C. Dinc

2009-01-01

140

Absorption Cross-Section of Ozone in the 590 to 610 nm Region at Different Temperatures.  

National Technical Information Service (NTIS)

The ozone absorption cross section in the 590 to 610 nm spectral range, a portion of the Chappuis bands, was measured at different temperatures. The values can be used in particular to invert atmospheric O3 data acquired by SAGE 2. The independence of the...

A. Amoruso M. Cacciani A. Disarra G. Fiocco

1988-01-01

141

Temperature response of photosynthesis in different drug and fiber varieties of Cannabis sativa L.  

PubMed

The temperature response on gas and water vapour exchange characteristics of three medicinal drug type (HP Mexican, MX and W1) and four industrial fiber type (Felinq 34, Kompolty, Zolo 11 and Zolo 15) varieties of Cannabis sativa, originally from different agro-climatic zones worldwide, were studied. Among the drug type varieties, optimum temperature for photosynthesis (Topt) was observed in the range of 30-35C in high potency Mexican HPM whereas, it was in the range of 25-30C in W1. A comparatively lower value (25C) for Topt was observed in MX. Among fiber type varieties, Topt was around 30C in Zolo 11 and Zolo 15 whereas, it was near 25C in Felinq 34 and Kompolty. Varieties having higher maximum photosynthesis (PN max) had higher chlorophyll content as compared to those having lower PN max. Differences in water use efficiency (WUE) were also observed within and among the drug and fiber type plants. However, differences became less pronounced at higher temperatures. Both stomatal and mesophyll components seem to be responsible for the temperature dependence of photosynthesis (PN) in this species, however, their magnitude varied with the variety. In general, a two fold increase in dark respiration with increase in temperature (from 20C to 40C) was observed in all the varieties. However, a greater increase was associated with the variety having higher rate of photosynthesis, indicating a strong association between photosynthetic and respiratory rates. The results provide a valuable indication regarding variations in temperature dependence of PN in different varieties of Cannabis sativa L. PMID:23573022

Chandra, Suman; Lata, Hemant; Khan, Ikhlas A; Elsohly, Mahmoud A

2011-07-01

142

The influence of CB loading on thermal aging resistance of SBR and NBR rubber compounds under different aging temperature  

Microsoft Academic Search

Aging temperatures play important role in changing the mechanical behavior of rubber, so thermal aging test under different temperatures was carried out to investigate the effect of aging temperatures on the tension, compression and hardness properties of styrene butadiene rubber (SBR) and nitrile butadiene rubber (NBR) compounds filled with different carbon black (CB) loading. The obtained results of five different

A. Mostafa; A. Abouel-Kasem; M. R. Bayoumi; M. G. El-Sebaie

2009-01-01

143

The influence of different acupuncture manipulations on the skin temperature of an acupoint.  

PubMed

This study was performed to observe the influence of sham and different verum acupuncture manipulations on skin temperature of the stimulated acupoint in healthy volunteers. Thirty-seven healthy volunteers with a mean age of 25.4 2.2 years were enrolled in the study. All volunteers had experienced acupuncture before. They received sham acupuncture and two different kinds of verum acupuncture stimulation (lifting-thrusting and twisting-rotating) on Zusanli (ST36). The skin temperature of ST36 was measured before acupuncture, after needle insertion, after needle manipulation, immediately after removal of the needle, and as further control 5 minutes after removal of the needle using a FLIR i7 infrared thermal camera. During the measurement, the needling sensations of volunteers were enquired and recorded. During the sham acupuncture stimulation, the skin temperature of ST36 decreased in the first 5 minutes, when the point was exposed, and then increased gradually. During verum acupuncture stimulations, the skin temperature increased continually and then decreased in the last phase. The increase in temperature caused by lifting-thrusting stimulation was significantly higher than that of twisting-rotating manipulation, which may be related to the stimulation intensity. PMID:23476709

Huang, Tao; Huang, Xin; Zhang, Weibo; Jia, Shuyong; Cheng, Xinnong; Litscher, Gerhard

2013-01-01

144

Co-doped sodium chloride crystals exposed to different irradiation temperature  

SciTech Connect

Monocrystals of NaCl:XCl{sub 2}:MnCl{sub 2}(X = Ca,Cd) at four different concentrations have been analyzed. The crystals were exposed to different irradiation temperature, such as at room temperature (RT), solid water (SW), dry ice (DI) and liquid nitrogen (LN). The samples were irradiated with photon from {sup 60}Co irradiators. The co-doped sodium chloride crystals show a complex structure of glow curves that can be related to different distribution of traps. The linearity response was analyzed with the F(D) index. The F(D) value was less than unity indicating a sub-linear response was obtained from the TL response on the function of the dose. The glow curves were deconvoluted by using the CGCD program based on the first, second and general order kinetics.

Ortiz-Morales, A. [Unidad Profesional Interdisciplinaria de Ingenieria y Tecnologias Avanzadas, IPN, Av. Instituto Politecnico Nacional 2580, Col. La Laguna Ticoman, 07340 Mexico D.F., Mexico and Unidad de Irradiacion y Segurid (Mexico); Cruz-Zaragoza, E.; Furetta, C. [Unidad de Irradiacion y Seguridad Radiologica, Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, 04510 Mexico D.F (Mexico); Kitis, G. [Nuclear Physics Laboratory, Aristotle University of Thessaloniki, Thessaloniki 54124 (Greece); Flores J, C.; Hernandez A, J.; Murrieta S, H. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, AP. 20-364, 01000 Mexico D.F (Mexico)

2013-07-03

145

Co-doped sodium chloride crystals exposed to different irradiation temperature  

NASA Astrophysics Data System (ADS)

Monocrystals of NaCl:XCl2:MnCl2(X = Ca,Cd) at four different concentrations have been analyzed. The crystals were exposed to different irradiation temperature, such as at room temperature (RT), solid water (SW), dry ice (DI) and liquid nitrogen (LN). The samples were irradiated with photon from 60Co irradiators. The co-doped sodium chloride crystals show a complex structure of glow curves that can be related to different distribution of traps. The linearity response was analyzed with the F(D) index. The F(D) value was less than unity indicating a sub-linear response was obtained from the TL response on the function of the dose. The glow curves were deconvoluted by using the CGCD program based on the first, second and general order kinetics.

Ortiz-Morales, A.; Cruz-Zaragoza, E.; Furetta, C.; Kitis, G.; Flores J., C.; Hernndez A., J.; Murrieta S., H.

2013-07-01

146

Photoreflectance Investigations of Temperature Dependence of the ``Different'' Energy Gaps in GaInNAs Compounds  

NASA Astrophysics Data System (ADS)

In this paper, we report photoreflectance investigations of GaInNAs layers almost lattice-matched to GaAs substrate and annealed at different temperatures. Our investigations done from 10 K to room temperature give evidence that these layers exhibit several distinct band gaps. These distinct band gaps, which were found to co-exist, are associated with different nitrogen bonding configurations (N-Ga4-mInm (0<= m <=4) short-range-order clusters). The annealing-induced blueshift of GaInNAs band gap energy, which is usually observed in this system, is due to the change in the intensity of PR resonances related to different N-Ga4-mInm configurations.

Kudrawiec, R.; Misiewicz, J.; Pavelescu, E.-M.; Konttinen, J.; Pessa, M.

2005-06-01

147

Temperature Integration: An efficient procedure for calculation of free energy differences  

NASA Astrophysics Data System (ADS)

We propose a method, Temperature Integration, which allows an efficient calculation of free energy differences between two systems of interest, with the same degrees of freedom, which may have rough energy landscapes. The method is based on calculating, for each single system, the difference between the values of lnZ at two temperatures, using a Parallel Tempering procedure. If our two systems of interest have the same phase space volume, they have the same values of lnZ at high-T, and we can obtain the free energy difference between them, using the two single-system calculations described above. If the phase space volume of a system is known, our method can be used to calculate its absolute (versus relative) free energy as well. We apply our method and demonstrate its efficiency on a toy model of hard rods on a 1-dimensional ring.

Farhi, Asaf; Hed, Guy; Bon, Michael; Caticha, Nestor; Mak, Chi H.; Domany, Eytan

2013-12-01

148

[Properties of maize stalk biochar produced under different pyrolysis temperatures and its sorption capability to naphthalene].  

PubMed

Biochar was made from maize stalk under three different temperatures of 300, 500 and 700 degreeC. The elemental composition of biochar was measured by elemental analyzer. Scanning electron microscope (SEM) was used to measure the surface morphology. Sorption of naphthalene to biochar was researched by batch sorption experiments. Results showed that, with the increase of temperature, C content increased from 66. 79% to 76. 30% , H and O contents decreased from 4.92% and 19. 25% to 3. 18% and 9.53%, respectively; H/C, O/C, (O + N)/C, aromaticity and hydrophobicity increased, and polarity decreased. SEM results showed that maize stalk biochar was platy particles, and its roughness of surface increased with increasing temperature. The sorption of naphthalene on biochar followed the Lagergren pseudo-second order dynamic sorption model. Initial sorption rate and equilibrium sorption capacity increased as preparation temperatures increased at the same initial concentration of naphthalene. The isotherm sorption behavior can be described by the Freundlich model, which indicated that, as pyrolysis temperature increased, the sorption capacity of biochar increased, and nonlinearity increased first and then decreased. Biochar derived from maize stalk had distinct features when compared with other feedstocks, and its elemental composition, surface features and sorption behaviors were significantly influenced by pyrolysis temperature. PMID:25055682

Huang, Hua; Wang, Ya-Xiong; Tang, Jing-Chun; Tang, Jing-Chun; Zhu, Wen-Ying

2014-05-01

149

Proteinase and phospholipase activities and development at different temperatures of yeasts isolated from bovine milk.  

PubMed

The presence of yeasts in milk may cause physical and chemical changes limiting the durability and compromising the quality of the product. Moreover, milk and dairy products contaminated by yeasts may be a potential means of transmission of these microorganisms to man and animals causing several kinds of infections. This study aimed to determine whether different species of yeasts isolated from bovine raw milk had the ability to develop at 37C and/or under refrigeration temperature. Proteinase and phospholipase activities resulting from these yeasts were also monitored at different temperatures. Five genera of yeasts (Aureobasidium sp., Candida spp., Geotrichum spp., Trichosporon spp. and Rhodotorula spp.) isolated from bovine raw milk samples were evaluated. All strains showed one or a combination of characteristics: growth at 37C (9909% of the strains), psychrotrophic behaviour (509%), proteinase production (1681% of the strains at 37C and 409% under refrigeration) and phospholipase production (3636% of the isolates at 37C and 109% under refrigeration), and all these factors may compromise the quality of the product. Proteinase production was similar for strains incubated at 37C (1681% of the isolates) and room temperature (1727%) but there was less amount of phospholipase-producing strains at room temperature (1545% of the isolates were positive) when compared with incubation at 37C (3636%). Enzymes production at 37C by yeasts isolated from milk confirmed their pathogenic potential. The refrigeration temperature was found to be most efficient to inhibit enzymes production and consequently ensure better quality of milk. The viability of yeasts and the activity of their enzymes at different temperatures are worrying because this can compromise the quality of dairy products at all stages of production and/or storage, and represent a risk to the consumer. PMID:21791151

Melville, Priscilla A; Benites, Nilson R; Ruz-Peres, Monica; Yokoya, Eugenio

2011-11-01

150

Autotrophic growth of bacterial and archaeal ammonia oxidizers in freshwater sediment microcosms incubated at different temperatures.  

PubMed

Both bacteria and archaea potentially contribute to ammonia oxidation, but their roles in freshwater sediments are still poorly understood. Seasonal differences in the relative activities of these groups might exist, since cultivated archaeal ammonia oxidizers have higher temperature optima than their bacterial counterparts. In this study, sediment collected from eutrophic freshwater Lake Taihu (China) was incubated at different temperatures (4C, 15C, 25C, and 37C) for up to 8 weeks. We examined the active bacterial and archaeal ammonia oxidizers in these sediment microcosms by using combined stable isotope probing (SIP) and molecular community analysis. The results showed that accumulation of nitrate in microcosms correlated negatively with temperature, although ammonium depletion was the same, which might have been related to enhanced activity of other nitrogen transformation processes. Incubation at different temperatures significantly changed the microbial community composition, as revealed by 454 pyrosequencing targeting bacterial 16S rRNA genes. After 8 weeks of incubation, [(13)C]bicarbonate labeling of bacterial amoA genes, which encode the ammonia monooxygenase subunit A, and an observed increase in copy numbers indicated the activity of ammonia-oxidizing bacteria in all microcosms. Nitrosomonas sp. strain Is79A3 and Nitrosomonas communis lineages dominated the heavy fraction of CsCl gradients at low and high temperatures, respectively, indicating a niche differentiation of active bacterial ammonia oxidizers along the temperature gradient. The (13)C labeling of ammonia-oxidizing archaea in microcosms incubated at 4 to 25C was minor. In contrast, significant (13)C labeling of Nitrososphaera-like archaea and changes in the abundance and composition of archaeal amoA genes were observed at 37C, implicating autotrophic growth of ammonia-oxidizing archaea under warmer conditions. PMID:23455342

Wu, Yucheng; Ke, Xiubin; Hernndez, Marcela; Wang, Baozhan; Dumont, Marc G; Jia, Zhongjun; Conrad, Ralf

2013-05-01

151

Thermographic imaging of facial skin--gender differences and temperature changes over time in healthy subjects  

PubMed Central

Objectives To assess changes in facial skin temperature over time, to identify sources of variation related to skin temperature and to evaluate interobserver reproducibility in measurements of the thermograms. Methods 62 volunteers (32 females, 30 males, mean age 23.4, range 19.529.5 years) underwent thermography of the face (left and right side lateral images) on four occasions with approximately 2 months between each session. Three observers recorded the images and marked regions of interest (ROIs) in each image using dedicated software. Smoking, exercise habits and use of oral contraceptives were recorded. Results A significant difference between sessions (?1 C, p < 0.001) and between observers (?0.11 C, p < 0.001) was identified. The difference between sides was not significant (?0.07 C, p = 0.7). None of the interactions between side, session and observer were significant. Smoking, exercise habits and oral contraceptive intake were not significant impact factors when included as covariates in the analysis (p > 0.1). ROI temperature was significantly higher in males than in females (0.7 C, p < 0.001). A mixed model analysis of variance showed that observer had little impact on the expected standard deviation, whereas session and subject had a greater impact. Conclusions Face temperature is symmetrical and varies over time. The non-significant difference between sides is highly reproducible, even between observers.

Christensen, J; Vaeth, M; Wenzel, A

2012-01-01

152

Comparison of microbial diversity during column bioleaching of chalcopyrite at different temperatures.  

PubMed

Column bioleaching of chalcopyrite was conducted at 33, 45, and 65?C, and the copper leaching rates after 220 days were 38.50, 51.35, and 56.75%, respectively. In order to compare the microbial diversity at different temperatures, the microbial community structures of both bacteria and archaea in the columns were analyzed using 16S rRNA gene clone library on day 220. Clone library results indicated that although both iron oxidizers and sulfur oxidizers occurred at all temperatures, iron oxidizers were dominant at 33 and 45?C and sulfur oxidizers were predominant at 65?C. With regard to bacterial community structure, Leptospirillum ferriphilum was the principal bacterium at 33 and 45?C, and uncultured sulfur-oxidizing symbiont bacteria were dominant at 65?C. On the other hand, with regard to archaea, only Ferroplasma sp. was detected at 33?C, cultures similar to uncultured archaeon clone were dominant at 45?C, and Metallosphaera sedula was predominant at 65?C. Thus, it is suggested that different community structures occur at different temperatures, and that thermophilic chalcopyrite bioleaching should be inoculated and operated at high temperature in order to allow thermophiles to become the dominant microorganism in the system. PMID:23832814

Chen, Bowei; Wu, Biao; Liu, Xingyu; Wen, Jiankang

2014-06-01

153

Influence of Air Temperature Difference on the Snow Melting Simulation of SWAT Model  

NASA Astrophysics Data System (ADS)

The temperature-index models are commonly used to simulate the snowmelt process in mountain areas because of its good performance, low data requirements, and computational simplicity. Widely used distributed hydrological model: Soil and Water Assessment Tool (SWAT) model is also using a temperature-index module. However, the lack of monitoring air temperature data still involves uncertainties and errors in its simulation performance especially in data sparse area. Thus, to evaluate the different air temperature data influence on the snow melt of the SWAT model, five different air temperature data are applied in two different Russia basins (Birobidjan basin and Malinovka basin). The data include the monitoring air temperature data (TM), NCEP reanalysis data (TNCEP), the dataset created by inverse distance weighted interpolation (IDW) method (TIDW), the dataset created by improved IDW method considering the elevation influence (TIDWEle), and the dataset created by using linear regression and MODIS Land Surface Temperature (LST) data (TLST). Among these data, the TLST , the TIDW and TIDWEle data have the higher spatial density, while the TNCEP and TM DATA have the most valid monitoring value for daily scale. The daily simulation results during the snow melting seasons (March, April and May) showed reasonable results in both test basins for all air temperature data. While R2 and NSE in Birobidjan basin are around 0.6, these values in Malinovka basin are over 0.75. Two methods: Generalized Likelihood Uncertainty Estimation (GLUE) and Sequential Uncertainty Fitting, version. 2 (SUFI-2) were used for model calibration and uncertainty analysis. The evolution index is p-factor which means the percentage of measured data bracketed by the 95% Prediction Uncertainty (95PPU). The TLST dataset always obtained the best results in both basins compared with other datasets. On the other hand, the two IDW based method get the worst results among all the scenarios. Totally, the performances of the data created from the MODIS land surface temperature which have a high spatial density are better than other data and can directly improve the snow melting results of SWAT model and reduce the uncertainty to a certain extend.

YAN, Y.; Onishi, T.

2013-12-01

154

Modelling adult Aedes aegypti and Aedes albopictus survival at different temperatures in laboratory and field settings  

PubMed Central

Background The survival of adult female Aedes mosquitoes is a critical component of their ability to transmit pathogens such as dengue viruses. One of the principal determinants of Aedes survival is temperature, which has been associated with seasonal changes in Aedes populations and limits their geographical distribution. The effects of temperature and other sources of mortality have been studied in the field, often via mark-release-recapture experiments, and under controlled conditions in the laboratory. Survival results differ and reconciling predictions between the two settings has been hindered by variable measurements from different experimental protocols, lack of precision in measuring survival of free-ranging mosquitoes, and uncertainty about the role of age-dependent mortality in the field. Methods Here we apply generalised additive models to data from 351 published adult Ae. aegypti and Ae. albopictus survival experiments in the laboratory to create survival models for each species across their range of viable temperatures. These models are then adjusted to estimate survival at different temperatures in the field using data from 59 Ae. aegypti and Ae. albopictus field survivorship experiments. The uncertainty at each stage of the modelling process is propagated through to provide confidence intervals around our predictions. Results Our results indicate that adult Ae. albopictus has higher survival than Ae. aegypti in the laboratory and field, however, Ae. aegypti can tolerate a wider range of temperatures. A full breakdown of survival by age and temperature is given for both species. The differences between laboratory and field models also give insight into the relative contributions to mortality from temperature, other environmental factors, and senescence and over what ranges these factors can be important. Conclusions Our results support the importance of producing site-specific mosquito survival estimates. By including fluctuating temperature regimes, our models provide insight into seasonal patterns of Ae. aegypti and Ae. albopictus population dynamics that may be relevant to seasonal changes in dengue virus transmission. Our models can be integrated with Aedes and dengue modelling efforts to guide and evaluate vector control, better map the distribution of disease and produce early warning systems for dengue epidemics.

2013-01-01

155

Inactivation of Escherichia coli by high hydrostatic pressure at different temperatures in buffer and carrot juice  

Microsoft Academic Search

The inactivation of Escherichia coli MG1655 was studied at 256 different pressure (150600 MPa)temperature (545 C) combinations under isobaric and isothermal conditions in HepesKOH buffer (10 mM, pH 7.0) and in fresh carrot juice. A linear relationship was found between the log10 of inactivation and holding time for all pressuretemperature combinations in carrot juice, with R2-values?0.91. Decimal reduction times (D-values),

Isabelle Van Opstal; Suzy C. M. Vanmuysen; Elke Y. Wuytack; Barbara Masschalck; Chris W. Michiels

2005-01-01

156

Phase Diagram Calculation and Experiment for Fe-Mn System at Different Temperature  

NASA Astrophysics Data System (ADS)

The phase equilibrium of the Fe-Mn-Al ternary system plays an important role in development of cryogenic alloys and heat-resistant steels. In the present work, the isothermal sections of Fe-Mn-Al system were calculated at different temperatures from 1500 C to 400 C at an interval of 100 C. The calculated results indicate that there is a three-phase region (?+?+?Mn) from 1000 C to 400 C. The position of the three-phase region (?+?+?Mn) moves to the lower Mn content region with temperature decreasing. Besides, the relative experiments also processed by use of optical microscopy and electron probe after heat treatment for equilibrium condition.

Zhang, Y. T.; Li, X. Y.; Li, D. Z.; Li, Y. Y.

2008-03-01

157

Differences in the H-mode pedestal width of temperature and density  

NASA Astrophysics Data System (ADS)

A pedestal database was built using data from type-I ELMy H-modes of ASDEX Upgrade, DIII-D and JET. ELM synchronized pedestal data were analysed with the two-line method. The two-line method is a bilinear fit which shows better reproducibility of pedestal parameters than a modified hyperbolic tangent fit. This was tested with simulated and experimental data. The influence of the equilibrium reconstruction on pedestal parameters was investigated with sophisticated reconstructions from CLISTE and EFIT including edge kinetic profiles. No systematic deviation between the codes could be observed. The flux coordinate system is influenced by machine size, poloidal field and plasma shape. This will change the representation of the width in different coordinates, in particular, the two normalized coordinates ?N and r/a show a very different dependence on the plasma shape. The scalings derived for the pedestal width, ?, of all machines suggest a different scaling for the electron temperature and the electron density. Both cases show similar dependence with machine size, poloidal magnetic field and pedestal electron temperature and density. The influence of ion temperature and toroidal magnetic field is different on each of \\Delta_{T_\\rme} and \\Delta_{n_\\rme} . In dimensionless form the density pedestal width in ?N scales with \\rho^{0.6}_{i\\star} , the temperature pedestal width with \\beta_p,ped^{0.5} . Both widths also show a strong correlation with the plasma shape. The shape dependence originates from the coordinate transformation and is not visible in real space. The presented scalings predict that in ITER the temperature pedestal will be appreciably wider than the density pedestal.

Schneider, P. A.; Wolfrum, E.; Groebner, R. J.; Osborne, T. H.; Beurskens, M. N. A.; Dunne, M. G.; Ferron, J. R.; Gnter, S.; Kurzan, B.; Lackner, K.; Snyder, P. B.; Zohm, H.; the ASDEX Upgrade Team; the DIII-D Team; EFDA Contributors, JET

2012-10-01

158

Algorithm development for land surface temperature measurement from GOES-R satellite  

NASA Astrophysics Data System (ADS)

The Geostationary Operational Environmental Satellite (GOES) program is developing a new generation sensor, the Advanced Baseline Imager (ABI), to be carried on the GOES-R satellite to be lunched in approximately in 2014. Compared to the current GOES imager, ABI will have significant advantages for measuring land surface temperature as well as to providing qualitative and quantitative data for a wide range of applications. Specifically, spatial resolution of the ABI sensor is 2 km, and the infrared window noise equivalent temperature is 0.1 K, which are very close to the polarorbiting satellite sensors such as AVHRR. Most importantly, ABI observes the full disk every five minutes, which not only provides more cloud-free measurements but also makes daily temperature variation analysis possible. In this study we developed split window algorithms for the LST measurement from the ABI sensor. We generated the ABI sensor data using MODTRAN radiative transfer model and NOAA88 atmospheric profiles and ran regression analyses for the LST algorithm development. The algorithms are developed by optimizing existing split window LST algorithms and adding a path length correction term to minimize the retrieval errors due to difference atmospheric path absorption from nadir view to the edge-of-scan. The algorithm coefficients are stratified for dry and moist atmospheric conditions, as well as for the daytime and nighttime. The algorithm sensitivity to land surface emissivity uncertainty is analyzed to ensure the algorithm performance.

Yu, Yunyue; Tarpley, Dan; Raja, M. K. Rama Varma; Xu, Hui; Privette, Jeffrey L.

2007-10-01

159

Archaeal Community Structures in the Solfataric Acidic Hot Springs with Different Temperatures and Elemental Compositions  

PubMed Central

Archaeal 16S rRNA gene compositions and environmental factors of four distinct solfataric acidic hot springs in Kirishima, Japan were compared. The four ponds were selected by differences of temperature and total dissolved elemental concentration as follows: (1) Pond-A: 93C and 1679?mg?L?1, (2) Pond-B: 66C and 2248?mg?L?1, (3) Pond-C: 88C and 198?mg?L?1, and (4) Pond-D: 67C and 340?mg?L?1. In total, 431 clones of 16S rRNA gene were classified into 26 phylotypes. In Pond-B, the archaeal diversity was the highest among the four, and the members of the order Sulfolobales were dominant. The Pond-D also showed relatively high diversity, and the most frequent group was uncultured thermoacidic spring clone group. In contrast to Pond-B and Pond-D, much less diverse archaeal clones were detected in Pond-A and Pond-C showing higher temperatures. However, dominant groups in these ponds were also different from each other. The members of the order Sulfolobales shared 89% of total clones in Pond-A, and the uncultured crenarchaeal groups shared 99% of total Pond-C clones. Therefore, species compositions and biodiversity were clearly different among the ponds showing different temperatures and dissolved elemental concentrations.

Watanabe, Keiko; Yamamoto, Hideo; Yamamoto, Shuichi

2013-01-01

160

Prediction of the resolution of capillary columns in different conditions of inlet pressure and temperature.  

PubMed

A procedure previously described for the prediction of the plate height of capillary columns operated at different inlet pressure of the carrier gas and at various column temperatures by using few retention data measured under isobaric conditions was modified and improved in order to permit the prediction of the retention times and of the peak widths at various heights. It is therefore possible to calculate the ratio, delta, between the peak width at different heights and the peak width at half height, whose value is used to predict the resolution at different height of two closely eluting peaks. It was found that the delta values do not depend on temperature and inlet pressure and are a characteristic of the used column; they can therefore be used in order to calculate the resolution in any temperature and inlet pressure condition. The method was used to predict the retention time, the peak width and the resolution of polar and non-polar compounds (alkanes, alkenes, chloroalkanes, alcohols, ketones) on capillary columns of different length and polarity by using as the starting data retention and width values measured in three isobaric runs only. PMID:14763748

Vezzani, S; Moretti, P; Castello, G; Travaini, G

2004-02-13

161

Comparison of the spores of Paenibacillus polymyxa prepared at different temperatures.  

PubMed

Paenibacillus polymyxa SQR-21, which is antagonistic against Fusarium oxysporum, is used as a biocontrol agent and, when mixed with organic substances for solid fermentation, produces a bioorganic fertilizer. The spores of P. polymyxa prepared at different temperatures were characterized with respect to the dipicolinic acid content, heat resistance, fatty acid composition and germination. Spores prepared at 37C showed higher heat resistance than those prepared at 25 and 30C. However, the germination rate was negatively correlated with the sporulation temperature. The maximum germination rate of the spores prepared at 25C was 1.3-times higher than the spores prepared at 30C. The sporulation temperature thus affects the resistance and germination properties of P. polymyxa spores. These results are useful for the production of improved bio-organic fertilizer. PMID:22294453

Huo, Zhenhua; Zhang, Nan; Raza, Waseem; Huang, Xinqi; Yong, Xiaoyu; Liu, Yunpeng; Wang, Dandan; Li, Shuqing; Shen, Qirong; Zhang, Ruifu

2012-05-01

162

Rutile titanium dioxide films deposited with a vacuum arc at different temperatures  

NASA Astrophysics Data System (ADS)

Rutile crystalline phase of TiO2 has been one of the most investigated materials for medical applications. Its implementation as a surface layer on biomedical implants has shown to improve hemocompatibility and biocompatibility. In this work, titanium dioxide coatings were deposited on glass and steel 316L substrates using cathodic arc deposition. The coatings were obtained at different substrate temperatures; varying from room temperature to 600C. The crystalline structure of the films was identified by glancing angle X-ray diffraction. Depending on the substrate material and on its temperature during the deposition process, anatase, anatse+rutile and rutile structures were observed. It was determined that rutile films can be obtained below 600 C with this deposition method.

Arias, L. Franco; Kleiman, A.; Heredia, E.; Mrquez, A.

2012-06-01

163

Microbial oxidation of CH(4) at different temperatures in landfill cover soils.  

PubMed

Biological oxidation of CH(4) is an important constraint on the emission of this gas from areas, such as landfills to the atmosphere. We studied the effect of temperature on methanotrophic bacteria in three different landfill cover soils, incubated in the laboratory. In samples of a young cover, consisting of wood chips and sewage sludge, the phospholipid fatty acids (PLFAs), regarded as biomarkers for type I methanotrophs (16:1omega5t, 16:1omega6c, 16:1omega8c), primarily increased at low temperatures (5-10 degrees C). On the other hand, the PLFA marker for type II methanotrophs (18:1omega8c) was highly elevated only at 20 degrees C. These results suggest that temperature can determine the selection of methanotroph populations. PMID:19712300

Brjesson, Gunnar; Sundh, Ingvar; Svensson, Bo

2004-06-01

164

The influence of serial feeding of drinks at different temperatures on thermoregulatory responses during cycling.  

PubMed

In this study, we examined thermoregulatory responses to ingestion of separate aliquots of drinks at different temperatures during low-intensity exercise in conditions of moderate heat stress. Eight men cycled at 50% (s = 3) of their peak oxygen uptake (VO2peak) for 90 min (dry bulb temperature: 25.3 degrees C, s = 0.5; relative humidity: 60%, s = 5). Four 400-ml aliquots of flavoured water at 10 degrees C (cold), 37 degrees C (warm) or 50 degrees C (hot) were ingested after 30, 45, 60, and 75 min of exercise. Immediately after the 90 min of exercise, participants cycled at 95% VO2peak to exhaustion to assess exercise capacity. There were no differences between trials in rectal temperature at the end of the 90 min of exercise (cold: 38.11 degrees C, s = 0.30; warm: 38.10 degrees C, s = 0.33; hot: 38.21 degrees C, s = 0.30; P = 0.765). Mean skin temperature between 30 and 90 min tended to be influenced by drink temperature (cold: 34.49 degrees C, s = 0.64; warm: 34.53 degrees C, s = 0.69; hot: 34.71 degrees C, s = 0.48; P = 0.091). Mean heart rate from 30 to 90 min was higher in the hot trial (129 beats . min(-1), s = 7; P < 0.05) than on the cold (124 beats . min(-1), s = 9) and warm trials (126 beats . min(-1), s = 8). Ratings of thermal sensation were higher on the hot trial than on the cold trial at 35 and 50 min (P < 0.05). Exercise capacity was similar between trials (P = 0.963). The heat load and debt induced by periodic drinking resulted in similar body temperatures during low-intensity exercise in conditions of moderate heat stress due to appropriate thermoregulatory reflexes. PMID:18344129

Lee, Jason K W; Maughan, Ron J; Shirreffs, Susan M

2008-04-01

165

Bacillus spore inactivation differences after combined mild temperature and high pressure processing using two pressurizing fluids.  

PubMed

Spores of six species (28 strains) of dairy Bacillus isolates were added to sterile reconstituted skim milk and pressure processed (600 MPa for 60 s at 75 degrees C) using either a water-based pressurizing fluid or silicon oil. Processing temperatures peaked at 88 and 90 degrees C, respectively, for both fluids. For all strains, the log inactivation was consistently higher in the silicon oil than in the water-based fluid. This has potential implications for food safety assessment of combined pressure-temperature processes. High pressure processing causes mild heating during pressurization of both the target sample (i.e., spores) and the pressurizing fluid used for pressure delivery. Primarily, the adiabatic heat of compression of the fluids as well as other heat-transfer properties of the fluids and equipment determines the magnitude of this heating. Pressure cycles run with silicon oil were 7 to 15 degrees C higher in temperature during pressurization than pressure cycles run with the water-based pressurizing fluid, due to the greater adiabatic heat of compression of silicon oil. At and around the target pressure, however, the temperatures of both pressurizing fluids were similar, and they both dropped at the same rate during the holding time at the target pressure. We propose that the increased spore inactivation in the silicon oil system can be attributed to additional heating of the spore preparation when pressurized in oil. This could be explained by the temperature difference between the silicon oil and the aqueous spore preparation established during the pressurization phase of the pressure cycle. These spore-inactivation differences have practical implications because it is common practice to develop inactivation kinetic data on small, jacketed laboratory systems pressurized in oil, with extensive heat loss. However, commercial deployment is invariably on large industrial systems pressurized in water, with limited heat loss. Such effects should be considered in food safety assessments of combined pressure-temperature processes. PMID:18592744

Robertson, Rosalind E; Carroll, Tim; Pearce, Lindsay E

2008-06-01

166

The performance improvement calculation of corrugated quantum well infrared photodetector (C-QWIP) with a high critical temperature (Tc) superconducting electron filter  

NASA Astrophysics Data System (ADS)

The Corrugated Quantum Well Infrared Photodetector (C-QWIP) holds significant performance and other advantages over other infrared (IR) detectors. However, one disadvantage of the detector is the relatively low operating temperature needed to suppress the dark current. By coating two additional layers (thin insulator and high critical temperature (Tc) superconductor) on the top contact layer of a C-QWIP wafer, the top three layers of the detector form a high-Tc superconducting single electron tunneling junction. It could act as an electron filter because of the presence of an energy gap in superconductors. For QWIPs, the photo electrons and dark electrons are well separated in energy, most dark current is conducting below the quantum well (QW) barrier height and most photo current is conducting above the barrier height. Most dark electrons thus could be blocked by the junction while most photo electrons pass the junction by applying an appropriate voltage. Therefore, both the sensitivity and the operating temperature of the detector could be improved. Our calculation shows that the filter could provide 40% or 70% improvement in Noise Equivalent Temperature Difference (NETD) of detector focal plane arrays (FPAs) at normal operating temperature, depending on whether the detector emitter photocurrent to dark current ratio is = 1 (Emitter is background limited BLIP) or = 0.1 (Emitter is far from BLIP). For both cases, the filter could increase the detector FPAs operating temperatures up to 90K (30K improvement) with 15% to 25% NETD improvement respectively.

Sun, Jason; Choi, K. K.

2011-09-01

167

Analyzing the Impact of Ambient Temperature Indicators on Transformer Life in Different Regions of Chinese Mainland  

PubMed Central

Regression analysis is applied to quantitatively analyze the impact of different ambient temperature characteristics on the transformer life at different locations of Chinese mainland. 200 typical locations in Chinese mainland are selected for the study. They are specially divided into six regions so that the subsequent analysis can be done in a regional context. For each region, the local historical ambient temperature and load data are provided as inputs variables of the life consumption model in IEEE Std. C57.91-1995 to estimate the transformer life at every location. Five ambient temperature indicators related to the transformer life are involved into the partial least squares regression to describe their impact on the transformer life. According to a contribution measurement criterion of partial least squares regression, three indicators are conclusively found to be the most important factors influencing the transformer life, and an explicit expression is provided to describe the relationship between the indicators and the transformer life for every region. The analysis result is applicable to the area where the temperature characteristics are similar to Chinese mainland, and the expressions obtained can be applied to the other locations that are not included in this paper if these three indicators are known.

Bai, Cui-fen; Gao, Wen-Sheng; Liu, Tong

2013-01-01

168

Analyzing the impact of ambient temperature indicators on transformer life in different regions of Chinese mainland.  

PubMed

Regression analysis is applied to quantitatively analyze the impact of different ambient temperature characteristics on the transformer life at different locations of Chinese mainland. 200 typical locations in Chinese mainland are selected for the study. They are specially divided into six regions so that the subsequent analysis can be done in a regional context. For each region, the local historical ambient temperature and load data are provided as inputs variables of the life consumption model in IEEE Std. C57.91-1995 to estimate the transformer life at every location. Five ambient temperature indicators related to the transformer life are involved into the partial least squares regression to describe their impact on the transformer life. According to a contribution measurement criterion of partial least squares regression, three indicators are conclusively found to be the most important factors influencing the transformer life, and an explicit expression is provided to describe the relationship between the indicators and the transformer life for every region. The analysis result is applicable to the area where the temperature characteristics are similar to Chinese mainland, and the expressions obtained can be applied to the other locations that are not included in this paper if these three indicators are known. PMID:23843729

Bai, Cui-fen; Gao, Wen-Sheng; Liu, Tong

2013-01-01

169

Implant Damage Studies with Different Implant Temperature by Spot and Ribbon Beam  

NASA Astrophysics Data System (ADS)

Wafer temperature during implant has a dominate effect on the amorphous layer thickness and post anneal residual defects which can result in difference in device performance and difficulties in tool matching between different implant systems, namely batch type vs. single wafer implanter and spot beam vs. ribbon beam system. Although the implant temperature set point can be well defined and controlled, the instantaneous temperature on wafer during implant is quite complicated interactions among beam shape, dose rate, duty cycle and cooling system to the behavior of defect generation and dynamic annealing. A batch system, iStar, and a single wafer system, iPulsar, which delivers both spot beam and ribbon beam with cold implant capability were used to study the effect of implant temperature to the post anneal residual defects by BF2 15 keV 31015 cm-2 implant after 850 C/30s anneal. Measurements from Rs, SIMS, plane view TEM are compared and analyzed. The results by ribbon beam and spot beam are also compared.

Chen, Hank; Jen, Causon Ko-Chuan; Lin, Tony; Matsunaga, Yasuhiko

2011-01-01

170

[IR spectral-analysis-based range estimation for an object with small temperature difference from background].  

PubMed

It is a typical passive ranging technology that estimation of distance of an object is based on transmission characteristic of infrared radiation, it is also a hotspot in electro-optic countermeasures. Because of avoiding transmitting energy in the detection, this ranging technology will significantly enhance the penetration capability and infrared conceal capability of the missiles or unmanned aerial vehicles. With the current situation in existing passive ranging system, for overcoming the shortage in ranging an oncoming target object with small temperature difference from background, an improved distance estimation scheme was proposed. This article begins with introducing the concept of signal transfer function, makes clear the working curve of current algorithm, and points out that the estimated distance is not unique due to inherent nonlinearity of the working curve. A new distance calculation algorithm was obtained through nonlinear correction technique. It is a ranging formula by using sensing information at 3-5 and 8-12 microm combined with background temperature and field meteorological conditions. The authors' study has shown that the ranging error could be mainly kept around the level of 10% under the condition of the target and background apparent temperature difference equal to +/- 5 K, and the error in estimating background temperature is no more than +/- 15 K. PMID:23586223

Fu, Xiao-Ning; Wang, Jie; Yang, Lin

2013-01-01

171

Fabrication and properties of YBa2Cu3O7- x ceramics at different sintering temperatures  

NASA Astrophysics Data System (ADS)

The influence of sintering temperatures on the fabrication of YBCO ceramics under normal air atmosphere was investigated in this study. YBCO ceramics were prepared by mixing starting compounds of Y2O3, BaCO3 and CuO powders, which were calcined at 850C for 12 h. The powder was pelletized and sintered at different temperatures, from 930C-1050C, for 12 h. Phase identification was carried out by x-ray diffraction (XRD) technique. Scanning electron microscopy (SEM) with energy dispersive x-ray analysis (EDS) was used to study microstructure and chemical composition. In addition, density, Vickers hardness properties, the change of resistance and dielectric properties with temperature above T c were investigated. It was found that, at 950C-1000C, high-purity YBCO ceramic could be obtained. Outside this temperature range, either impurity phases were present or melting occurred. SEM images showed that grain size, which ranged from 1.5-2.5 m, and hardness were related to density and liquid phase present in the sample. Furthermore, the sintering temperature affected oxygen content which, in turn, determined the conductive or semi-conductive behavior observed by electrical property measurement.

Prayoonphokkharat, Poom; Jiansirisomboon, Sukanda; Watcharapasorn, Anucha

2013-07-01

172

Improving the Accuracy of Satellite Sea Surface Temperature Measurements by Explicitly Accounting for the Bulk-Skin Temperature Difference.  

National Technical Information Service (NTIS)

The focus of this research was to determine whether the accuracy of satellite measurements of sea surface temperature (SST) could be improved by explicitly accounting for the complex temperature gradients at the surface of the ocean associated with the co...

S. L. Castro W. J. Emery

2002-01-01

173

A Study of Contact Binaries with Large Temperature Differences between Components  

NASA Astrophysics Data System (ADS)

We present an extensive analysis of new light and radial velocity (RV) curves, as well as high quality broadening function (BF) profiles of twelve binary systems for which a contact configuration with large temperature differences between components has been reported in the literature. We find that six systems (V1010 Oph, WZ Cyg, VV Cet, DO Cas, FS Lup, V747 Cen) have near contact configurations. For the remaining systems (CX Vir, FT Lup, BV Eri, FO Hya, CN And, BX And), our solutions of the new observations once again converge in a contact configuration with large temperature differences between the components. However, the bright regions discovered in the BFs for V747 Cen, CX Vir, FT Lup, BV Eri, FO Hya, and CN And, and further attributed to hot spots, shed new light on the physical processes taking place between the components and imply the possibility that the contact configurations obtained from light and RV curve modeling are a spurious result.

Siwak, M.; Zola, S.; Koziel-Wierzbowska, D.

2010-12-01

174

Fabrication and optical characterization of nanoporous alumina films annealed at different temperatures  

NASA Astrophysics Data System (ADS)

We report on the structural and optical properties of self-ordered nanoporous anodic alumina (NAA) films annealed at different temperatures. The morphology of NAA films is examined by scanning electron microscopy (SEM). The results show that the porous structure have hexagonally ordered arrays of nanopores with interpore distance in the range of 90-100 nm and pore size between 30 and 40 nm. The structural properties studied by X-ray diffraction (XRD) show out that the nanoporous alumina experiences a transition from the amorphous phase to gamma and alpha phase when annealed from 800 to 1200 C. The optical transmission spectra of the annealed NAA films with different thicknesses (9, 24 and 45 ?m) are measured in the wavelength range of 300-1000 nm. Numerical simulations based on an optical model of the films show a good agreement with the measurements. The refractive index ( n) and the extinction coefficient ( k) are determined for each annealed temperature.

Marsal, L. F.; Vojkuvka, L.; Formentin, P.; Pallars, J.; Ferr-Borrull, J.

2009-04-01

175

Influence of temperature, time and different media on mesenchymal stromal cells shipped for clinical application.  

PubMed

Cell-based therapies, such as the use of mesenchymal stromal cells (MSCs), are becoming popular in veterinary medicine. When MSCs are not cryopreserved, they are shipped in suspension, but no previous studies have analyzed MSC viability during delivery. Here, the impact of several experimental shipping conditions on the number of equine blood-derived (ePB-MSC) and canine adipose-derived (cA-MSC) MSCs were evaluated. Among the different parameters tested, only time and temperature influenced MSC number during the experimental shipping conditions. Cells were monitored over different time intervals for gene expression of typical MSC markers and to evaluate acquired resistance to apoptosis and beta-galactosidase activity. Overall, these results indicate that ePB-MSC and cA-MSC should be delivered in phosphate buffered saline at room temperature and within 9-12 h. PMID:22503718

Bronzini, I; Patruno, M; Iacopetti, I; Martinello, T

2012-10-01

176

Pulmonary responses of asthmatic and normal subjects to different temperature and humidity conditions in an environmental chamber  

Microsoft Academic Search

Determining the possible adverse health effects of air pollutants can be complicated by differences in the environmental conditions of temperature and humidity. To evaluate the potentially confounding effects of differences in temperature and humidity, we exposed 8 normal male subjects and 8 male subjects with asthma to the extremes in temperature and humidity that could be maintained in an environmental

William L. Eschenbacher; Thomas B. Moore; Thomas J. Lorenzen; John G. Weg; Kenneth B. Gross

1992-01-01

177

Apparatus for measurement of thermal conductivity of insulation systems subjected to extreme temperature differences  

NASA Technical Reports Server (NTRS)

Advanced aerospace designs require thermal insulation systems which are consistent with cryogenic fluids, high thermal loads, and design restrictions such as weight and volume. To evaluate the thermal performance of these insulating systems, an apparatus capable of measuring thermal conductivity using extreme temperature differences (27 to 1100 K) is being developed. This system is described along with estimates of precision and accuracy in selected operating conditions. Preliminary data are presented.

Dube, W. P.; Sparks, L. L.; Slifka, A. J.; Bitsy, R. M.

1990-01-01

178

Charge-discharge characteristics of the mesocarbon microbeads heat-treated at different temperatures  

Microsoft Academic Search

Mesocarbon microbeads (MCMB) is one of the promising carbon materials as anodes for rechargeable lithium batteries among commercially available carbon materials. have examined the correlation between carbon structures and charge-discharge characteristics of the MCMBs prepared at different heat-treatment temperatures. It was found that the MCMB heat-treated at 700 C possesses a tremendously high charge-discharge capacity of 750 Ah\\/kg. This suggests

Akihiro Mabuchi; Katsuhisa Tokumitsu; Hiroyuki Fujimoto; Takahiro Kasuh

1995-01-01

179

Centralperipheral temperature difference, blood pressure, and arginine vasopressin in preterm neonates undergoing volume expansion  

Microsoft Academic Search

AIMTo examine the effect of intravascular volume expansion for the treatment of hypovolaemia in sick preterm neonates.METHODSAn intravenous infusion of 20 ml per kg of 4.5 % albumin was given to 14 preterm neonates. The effects on systolic blood pressure, central peripheral temperature difference (c-pT), and plasma arginine vasopressin concentration (pAVP) were measured.RESULTSThirteen babies showed a rise in systolic blood

Heather J Lambert; Peter H Baylis; Malcolm G Coulthard

1998-01-01

180

Effects of different excitation and detection spectral regions on room temperature chlorophyll a fluorescence parameters  

Microsoft Academic Search

The effects of different spectral region of excitation and detection of chlorophyll (Chl) a fluorescence at room temperature on the estimation of excitation energy utilization within photosystem (PS) 2 were studied in wild-type barley (Hordeum vulgare L. cv. Bonus) and its Chl b-less mutant chlorina f2 grown under low and high irradiances [100 and 1 000 mol(photon) m?2 s?1]. Three

M. Stroch; J. Podolinska; M. Navratil; V. Spunda

2005-01-01

181

Mineralization of Hormones in Breeder and Broiler Litters at Different Water Potentials and Temperatures  

Microsoft Academic Search

When poultry litter is landspread, steroidal hormones present in the litter may reach surface waters, where they may have undesirable biological effects. In a laboratory study, we determined the mineral- ization of (4- 14 C)-labeled 17b-estradiol, estrone, and testosterone in breeder litter at three different water potentials (256, 224, and 212 MPa) and temperatures (25, 35, and 45C), and in

Sarah N. J. Hemmings; Peter G. Hartel

2006-01-01

182

Characterization of Tin disulphide thin films prepared at different substrate temperature using spray pyrolysis technique  

Microsoft Academic Search

Thin films of tin disulphide on glass substrates were prepared by spray pyrolysis technique using precursor solutions of SnCl22H2O and nn dimethyl thiourea at different substrate temperatures varied in the range 348423K. Using the hot probe technique\\u000a the type of conductivity is found to be n type. X ray diffraction analysis revealed the polycrystalline nature with increasing\\u000a crystallinity with respect

K. Vijayakumar; C. Sanjeeviraja; M. Jayachandran; L. Amalraj

2011-01-01

183

A multigrid method for natural convective heat transfer with large temperature differences  

Microsoft Academic Search

Steady-state two-dimensional solutions to the full compressible NavierStokes equations are computed for laminar convective motion of a gas in a square cavity with large horizontal temperature differences. Results for air are presented. The ideal-gas law is used and viscosity is given by Sutherland's law. An accurate low-Mach number solver is developed. Hereby an explicit third-order discretization for the convective part

Jan Vierendeels; Bart Merci; Erik Dick

2004-01-01

184

Influence of temperature difference calculation method on the evaluation of Rankine cycle performance  

NASA Astrophysics Data System (ADS)

In the new century, energy and environmental problems are becoming more critical, and the development of natural energy is desired. Low-grade Thermal Energy Conversion (LTEC) is refocused as one of the renewable energy methods. The usefulness of LTEC is expected using hot springs and waste heat. In the case of the Rankine cycle using ammonia as the working fluid, the thermal properties of the working fluid changes in the evaporator. The traditional evaluation method of heat exchanger performance is the LMTD (Logarithmic Mean Temperature Difference) method. On the other hand, the GMTD (Generalized Mean Temperature Difference) method allows the variation of thermal properties in the heat exchanger. The aim of this study is to compare the two methods for the calculation of temperature differences and the corresponding influence on the total performance of the Rankine cycle that is operated using ammonia as a working fluid. As a result, the thermal efficiency of the Rankine cycle is greater than that of the LMTD method. Moreover, the computable range of the GMTD calculation method is less than that of the LMTD calculation method.

Morisaki, Takafumi.; Ikegami, Yasuyuki.

2014-02-01

185

Water structure-forming capabilities are temperature shifted for different models.  

PubMed

A large number of water models exist for molecular simulations. They differ in the ability to reproduce specific features of real water instead of others, like the correct temperature for the density maximum or the diffusion coefficient. Past analysis mostly concentrated on ensemble quantities, while few data were reported on the different microscopic behavior. Here, we compare seven widely used classical water models (SPC, SPC/E, TIP3P, TIP4P, TIP4P-Ew, TIP4P/2005, and TIP5P) in terms of their local structure-forming capabilities through hydrogen bonds for temperatures ranging from 210 to 350 K by the introduction of a set of order parameters taking into account the configuration of up to the second solvation shell. We found that all models share the same structural pattern up to a temperature shift. When this shift is applied, all models overlap onto a master curve. Interestingly, increased stabilization of fully coordinated structures extending to at least two solvation shells is found for models that are able to reproduce the correct position of the density maximum. Our results provide a self-consistent atomic-level structural comparison protocol, which can be of help in elucidating the influence of different water models on protein structure and dynamics. PMID:22651887

Shevchuk, Roman; Prada-Gracia, Diego; Rao, Francesco

2012-06-28

186

A comparison of three different types of temperature measurement in HITU fields  

NASA Astrophysics Data System (ADS)

The spatial and temporal distribution of the temperature elevation caused by high-intensity therapeutic ultrasound (HITU) in a tissue-mimicking material (TMM) has been determined with magnetic resonance (MR) thermometry, infrared (IR) thermometry and a thermal test object with an integrated thin-film thermocouple at three different National Metrological Institutes (PTB/Germany, NPL/UK, INRIM/Italy). Results obtained from the different types of measurement are compared and some general aspects of the methods are discussed, particularly with regard to their suitability for the in vitro characterization of transducers for treatment planning.

Haller, J.; Jenderka, K.-V.; Seifert, F.; Klepsch, T.; Martin, E.; Shaw, A.; Durando, G.; Guglielmone, C.; Girard, F.

2012-10-01

187

Impact response characteristics of a cyclotetramethylene tetranitramine based polymer-bonded explosives under different temperatures  

NASA Astrophysics Data System (ADS)

The temperature-impact safety correlation of a cyclotetramethylene tetranitramine (HMX) based polymer-bonded explosive (PBX) was investigated. Matrix of tests was determined by projectile velocities in the range of 160 m/s-370 m/s and five temperature cases of 28 C (room temperature), 75 C, 105 C, 160 C, and 195 C. The safety performance under thermal-impact combined environment was evaluated by high speed camera and air over-pressure gauges. The samples before and after impact were compared by the scanning electron microscope. The mechanical performance and thermal decomposition under different temperatures were also studied by mechanics machine and the thermo gravimetric analysis technique. The phase transition of PBX-2 is investigated by XRD spectrograph. The results show that the reaction threshold of unheated explosive is between 263.5 m/s and 269.9 m/s. While heated to 75 C and 105 C, the values are increased to 316 m/s-367 m/s and 286 m/s-298.3 m/s, respectively. However, the threshold is less than 176 m/s at 160 C and the threshold at 195 C is even lower, which is less than 166.7 m/s. According to the temperature histories, the pictures of wreckages, the over-pressures, the mechanical performance, the thermal decomposition, and phase transition properties, some conclusions can be drawn. First of all, compared with unheated case, the impact safety of PBX-2 is improved at both 75 C and 105 C by a softened, easy-flowing, and energy absorbing mechanical properties. Secondly, at 160 C, the impact safety becomes worse due to the thermal decomposition. Thirdly, when the temperature reaches or exceeds the ? --> ? phase transition range, the impact safety of PBX-2 becomes significantly worse.

Xiaogan, Dai; Yushi, Wen; Hui, Huang; Panjun, Zhang; Maoping, Wen

2013-09-01

188

Optical temperature switch based on microstructured fibre filled with different chemical mixtures  

NASA Astrophysics Data System (ADS)

Size, shape and location of the air holes allow to tailor microstructured fibre (MSF) parameters in a very wide range way beyond classical fibres what opens up many possibilities for various applications. Additionally, the propagation parameters of MSF can be actively tuned when the air-holes are filled with different gases, liquids (e.g., liquid crystals) or solid materials (e.g., polymers). The mode confinement in such a filled MSF can be affected by temperature dependent refractive index of material filling the fibre. This idea puts forward a new type of components for creating novel fibre devices such as switches, attenuators and others. Variable optical attenuators (VOAs) play an important role in optical communications as equalizers for dynamic channel power and wavelength division multiplexing in a transmission system. Controlling and monitoring of optical power are also necessary in sensing applications, and especially, in optical systems which require high power laser operation or critical temperature threshold monitoring. Various types of VOA have been developed based on different mechanisms, such as bending loss control, light leaking from the fibre cladding, temperature tuning of the polymer incorporated into the tapered microstructured fibre or electrical tuning of the liquid crystal layers. In this paper we would like to discuss the highly dynamic VOA based on a tuneable microstructured fibre filled with different chemical mixtures used as an on/off temperature switch. Furthermore, the technology of low loss coupling and splicing of the applied MSF with a standard single mode fibre has been developed. Therefore, in the proposed application an optical signal can be transmitted to and from the switch by a standard telecom fibre which considerably reduces transmission losses and allows for the use of standard off-the-shelf components reducing costs of the overall system.

Marc, P.; Piliszek, P.; Murawski, M.; Szymanski, M.; Nasilowski, T.; Jaroszewicz, L. R.

2012-05-01

189

Transformations in Sol-Gel Synthesized Nanoscale Hydroxyapatite Calcined Under Different Temperatures and Time Conditions  

NASA Astrophysics Data System (ADS)

Nano-hydroxyapatite (HAP) has been synthesized using sol-gel technique. Calcium nitrate tetrahydrate and potassium dihydrogen phosphate were used as precursors for calcium and phosphorus, respectively. A detailed study on its transformation during calcination at two crucial temperatures has been undertaken. The synthesized nanopowder was calcined at 600 and 800 C for different time periods. The results revealed that the obtained powders after calcining at 600 and 800 C are composed of hydroxyapatite nanoparticles. The nano-HAP powders were characterized by x-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, thermal gravimetric analysis (TGA), and BET surface area analyzer techniques. The results indicate that crystallite size as well as crystallinity of synthesized HAP nanopowders increase with increase in calcination temperature as well as calcination time, but the effect of temperature is more prominent as compared to that of calcination time. TEM micrograph revealed the presence of majority of HAP powder particles as agglomerates and a few as individual particles. It also revealed that HAP produced after sintering at 600 C is 26-45 nm in size, which is well in agreement with the crystallite size calculated using XRD data. TGA study showed the thermal stability of the as-synthesized nano-HAP powder. The BET surface area decreased with increase in calcination temperature and time. The results clearly demonstrate the significant role of calcination parameters on the characteristics of nano-HAP powders.

Seema, Kapoor; Uma, Batra; Suchita, Kohli

2012-08-01

190

Effect of Microcystis aeruginosa on the rotifer Brachionus calyciflorus at different temperatures.  

PubMed

Rotifers are one of the smallest metazoans. They serve as a model organism for ecotoxicological studies. More than 60% of the lakes in China are increasingly eutrophic and they are susceptible to blooms of Microcystis aeruginosa. We investigated the effects of M. aeruginosa on the survival and reproduction of Brachionus calyciflorus using the life table method at different temperatures. The findings showed that concentration of M. aeruginosa significantly affected the intrinsic rate of increase (r(m)), net reproductive rate (R(0)), average lifespan (L) and offspring number (p<0.05). Temperature also significantly affected the generation time (T), average lifespan (L) and offspring number (p<0.05). Moreover, the interaction between temperature and concentration had statistically significant effects on offspring number (p<0.05). M. aeruginosa suppressed the survival and reproduction of B. calyciflorus, particularly at a concentration of 10(6)cells/mL. The r(m) values of the rotifers exposed at 10(6)cells/mL decreased more than 200% compared with those of the control group. However, at a lower concentration, 10(4)cells/mL, M. aeruginosa may supply appropriate nourishment to rotifers. In addition, at concentrations of 10(5) and 10(6)cells/mL, the inhibition of rotifers by M. aeruginosa heightened with increasing temperature. PMID:22057279

Zhang, Xiong; Geng, Hong

2012-01-01

191

Temperature dependence of the optical properties of VO2 deposited on sapphire with different orientations  

NASA Astrophysics Data System (ADS)

Spectroscopic ellipsometry studies are reported for vanadium dioxide grown on c-, m-, and r-plane sapphire substrates. The crystallographic orientation of the VO2 depends strongly on the substrate, producing diverse strains in the layers which affect the interband transition energies and the phase transition temperatures. These structural differences correlate with distinct variations of the optical transitions observed in the ellipsometry results. For the m- and r-plane substrates, the VO2 appears to transform abruptly from the monoclinic phase to the rutile R structure as temperature is increased. In contrast, VO2 deposited on c-plane sapphire exhibits a sluggish transformation. For the m-plane sample, the energy gap collapses over a narrow temperature range. For the c-plane case, a broad temperature range is obtained between the onset and completion of the transformation. Raman studies of the vibrational structure show that internal stresses due to expansion and contraction across the phase transitions impacts the observed phonon energies.

Nazari, M.; Zhao, Y.; Kuryatkov, V. V.; Fan, Z. Y.; Bernussi, A. A.; Holtz, M.

2013-01-01

192

Intramuscular Temperature Differences Between the Mid-Point and Peripheral Effective Radiating Area With Ultrasound  

PubMed Central

The purpose of the study was to determine whether uniform intramuscular heating is achieved throughout a treatment area 2 times the transducer head at both 1 and 3 MHz. Seven male and three female subjects (Age: 23.6 1.0 yrs, Weight: 83.8 23.2 kg, Site Skinfold: 13.9 7.3 mm) underwent two ultrasound treatments (1 and 3 MHz) in the triceps surae muscle group. Thermocouples were inserted at the midpoint and periphery of the treatment area. Ten minute baseline temperatures were recorded followed by a ten minute ultrasound treatment. Two (site) X 10 (time) repeated measures ANOVAs were separately used to determine significance for 1 and 3 MHz treatments. Post-hoc testing was performed using the Bonferroni adjustment. A significant site-by-time interaction was observed for both the 1 and 3 MHz treatments. From baseline to the end of the treatment, temperature increased approximately 2.62C and 1.58C for the midpoint and periphery of the 1 MHz treatment and 5.88C and 3.64C for the 3 MHz treatment. The differences in temperature suggest that uniform heating does not occur throughout the treatment area. Key points 3 MHz is more effective in raising intramuscular temperature within ERA. Stroke count/rate of transducer may play a factor in heating tissue. Treatment size may alter uniform heating.

Miller, Michale G.; Longoria, Janae R.; Cheatham, Christopher C.; Baker, Robert J.; Michael, Timothy J.

2008-01-01

193

Life tables and development of Bemisia argentifolii (Homoptera: Aleyrodidae) at different temperatures.  

PubMed

The life history of Bemisia argentifolii Bellows & Perring (Homoptera: Aleyrodidae) on tomato (Lycopersicum spp.) was studied based on the age-stage, two-sex life table at 15, 20, 25, 28, 30, and 35 degrees C. The intrinsic rate of increase (r) at these temperatures is -0.0176, 0.0667, 0.1469, 0.1611, 0.1745, and 0.0989 d(-1), respectively. The relationship among the gross reproductive rate (GRR), the net reproductive rate (R0), and the preadult survivorship (l(a)) is consistent with GRR > l(a) x GRR > R0 for all results at different temperatures. The mean generation time is 81.9, 48.6, 28.4, 25.3, 22.1, and 18.2 d, respectively. The developmental rate of the egg stage at different temperatures fit a linear equation with a thermal summation 89.2 degree-days and a developmental threshold of 11.4 degrees C. The developmental rates of the nymphal stage fit the model of Stinner et al. and the parameters of C, Rmax, k1 and k2 were 0.085, 0.0833, 5.298, and -0.263, respectively. PMID:16813300

Yang, Ta-Chi; Chi, Hsin

2006-06-01

194

Mineralization of hormones in breeder and broiler litters at different water potentials and temperatures.  

PubMed

When poultry litter is landspread, steroidal hormones present in the litter may reach surface waters, where they may have undesirable biological effects. In a laboratory study, we determined the mineralization of [4-14C]-labeled 17beta-estradiol, estrone, and testosterone in breeder litter at three different water potentials (-56, -24, and -12 MPa) and temperatures (25, 35, and 45 degrees C), and in broiler litter at two different water potentials (-24 and -12 MPa) and temperatures (25 and 35 degrees C). Mineralization was similar in both litters and generally increased with increasing water content and decreasing temperature. After 23 wk at -24 MPa, an average of 27, 11, and <2% of the radiolabeled testosterone applied to breeder litter was mineralized to 14CO2 at 25, 35, and 45 degrees C, respectively. In contrast, mineralization of the radiolabeled estradiol and estrone was <2% after 25 wk at all water potentials, except after 17 wk at 25 degrees C and -12 MPa, where up to 5.9% of the estradiol and 7.8% of the estrone was mineralized. The minimal mineralization suggests that the litters may still be potential sources of hormones to surface and subsurface waters. PMID:16585611

Hemmings, Sarah N J; Hartel, Peter G

2006-01-01

195

Formation of brominated pollutants during the pyrolysis and combustion of tetrabromobisphenol A at different temperatures.  

PubMed

Tetrabromobisphenol A (TBBPA) is the most widely used brominated flame retardant worldwide. A detailed examination of the degradation products emitted during thermal decomposition of TBBPA is presented in the study. Runs were performed in a laboratory furnace at different temperatures (650 and 800C) and in different atmospheres (nitrogen and air). More than one hundred semivolatile compounds have been identified by GC/MS, with special interest in brominated ones. Presence of HBr and brominated light hydrocarbons increased with temperature and in the presence of oxygen. Maximum formation of PAHs is observed at pyrolytic condition at the higher temperature. High levels of 2,4-, 2,6- and 2,4,6- bromophenols were found. The levels of polybrominated dibenzo-p-dioxins and furans have been detected in the ppm range. The most abundant isomers are 2,4,6,8-TeBDF in pyrolysis and 1,2,3,7,8-PeBDF in combustion. These results should be considered in the assessment of thermal treatment of materials containing brominated flame retardants. PMID:24792882

Ortuo, Nuria; Molt, Julia; Conesa, Juan A; Font, Rafael

2014-08-01

196

Investigation of temperature and aridity at different elevations of Mt. Ailao, SW China.  

PubMed

Our current understanding is that plant species distribution in the subtropical mountain forests of Southwest China is controlled mainly by inadequate warmth. Due to abundant annual precipitation, aridity has been less considered in this context, yet rainfall here is highly seasonal, and the magnitude of drought severity at different elevations has not been examined due to limited access to higher elevations in this area.In this study, short-term micrometeorological variables were measured at 2,480 m and 2,680 m, where different forest types occur. Drought stress was evaluated by combining measurements of water evaporation demand (E p) and soil volumetric water content (VWC). The results showed that: (1) mean temperature decreased 1 C from 2,480 m to 2,680 m and the minimum temperature at 2,680 m was above freezing. (2) Elevation had a significant influence on E p; however, the difference in daily E p between 2,480 m and 2,680 m was not significant, which was possibly due to the small difference in elevation between these two sites. (3) VWC had larger range of annual variation at 2,680 m than at 2,480 m, especially for the surface soil layer.We conclude that the decrease in temperature does not effectively explain the sharp transition between these forest types. During the dry season, plants growing at 2,680 m are likely to experience more drought stress. In seeking to understand the mountain forest distribution, further studies should consider the effects of drought stress alongside those of altitude. PMID:22752399

You, Guangyong; Zhang, Yiping; Liu, Yuhong; Schaefer, Douglas; Gong, Hede; Gao, Jinbo; Lu, Zhiyun; Song, Qinghai; Zhao, Junbin; Wu, Chuansheng; Yu, Lei; Xie, Youneng

2013-05-01

197

Calibration and simulation of ASM2d at different temperatures in a phosphorus removal pilot plant.  

PubMed

In this work, an organic and nutrient removal pilot plant was used to study the temperature influence on phosphorus accumulating organisms. Three experiments were carried out at 13, 20 and 24.5 degrees C, achieving a high phosphorus removal percentage in all cases. The ASM2d model was calibrated at 13 and 20 degrees C and the Arrhenius equation constant was obtained for phosphorus removal processes showing that the temperature influences on the biological phosphorus removal subprocesses in a different degree. The 24.5 degrees C experiment was simulated using the model parameters obtained by means of the Arrhenius equation. The simulation results for the three experiments showed good correspondence with the experimental data, demonstrating that the model and the calibrated parameters were able to predict the pilot plant behaviour. PMID:16889256

Garca-Usach, F; Ferrer, J; Bouzas, A; Seco, A

2006-01-01

198

Piezoresistivity of polycrystalline p-type diamond films of various doping levels at different temperatures  

SciTech Connect

The piezoresistivity of polycrystalline p-type diamond films has been studied. The films were grown by microwave plasma assisted chemical vapor deposition and {ital in situ} doped with different concentrations of boron. A four-point electrical measurement was performed to evaluate the film resistivity change upon straining in a four-point bending beam setup. Films were glued directly onto a stainless steel beam and the silicon substrates were selectively removed. A gauge factor (relative change of the resistivity divided by the elastic strain) of about 690 under 100 microstrains was obtained at room temperature for a film doped with 32 ppm boron. With increasing temperature and dopant concentration the gauge factor increases. The experimental results obtained are discussed. {copyright} {ital 1997 American Institute of Physics.}

Wang, W.L.; Jiang, X.; Taube, K.; Klages, C. [Fraunhofer-Institut fuer Schicht- und Oberflaechentechnik (FhG-IST), Bienroder Weg 54 E, D-38108 Braunschweig (Germany)] [Fraunhofer-Institut fuer Schicht- und Oberflaechentechnik (FhG-IST), Bienroder Weg 54 E, D-38108 Braunschweig (Germany)

1997-07-01

199

Effects of helium and deuterium irradiation on SPS sintered W-Ta composites at different temperatures  

NASA Astrophysics Data System (ADS)

Energetic He+ and D+ ions were implanted into different W-Ta composites in order to investigate their stability under helium and deuterium irradiation. The results were compared with morphological and chemical modifications arising from exposure of pure W and Ta. Special attention was given to tantalum hydride (Ta2H) formation due to its implications for tritium inventory. Three W-Ta composites with 10 and 20 at.% Ta were prepared from elemental W powder and Ta fibre or powder through low-energy ball milling in argon atmosphere. Spark plasma sintering (SPS) was used as the consolidation process in the temperature range from 1473 to 1873 K. The results obtained from pure elemental samples and composites are similar. However, Ta2H is easily formed in pure Ta by using a pre-implantation stage of He+, whereas in W-Ta composites the same reaction is clearly reduced, and it can be inhibited by controlling the sintering temperature.

Mateus, R.; Dias, M.; Lopes, J.; Rocha, J.; Catarino, N.; Franco, N.; Livramento, V.; Carvalho, P. A.; Correia, J. B.; Hanada, K.; Alves, E.

2013-11-01

200

Terahertz absorption spectrum of para and ortho water vapors at different humidities at room temperature  

NASA Astrophysics Data System (ADS)

Terahertz time-domain spectroscopy has been used to measure the absorption of water vapor in 0.2-2.4 THz range from low to high humidity at room temperature. The observed absorption lines are due to the water molecular rotations in the ground vibrational state. We find that the absorption strength of para transitions increases as humidity increases, while the absorption strength of ortho transitions increases and then decreases in intensity with increasing humidity. We explain this difference based on the nuclear spin statistics based ratio of ortho to para water monomer populations at room temperature. The preferential adsorption on the solid surfaces of para water leads to an ortho dominated vapor cloud whose monomer rotational absorption intensity decreases due to the effects of dimerization, molecular collisions, clustering, and interactions with liquid droplets at high concentrations.

Xin, X.; Altan, H.; Saint, A.; Matten, D.; Alfano, R. R.

2006-11-01

201

Temperature dependent electrical conductivity measurement of Ad-(TCNQ)2 grown by different methods  

NASA Astrophysics Data System (ADS)

We measured the temperature dependent electrical conductivity on single crystal of Radical Ion Salts (RIS), Ad-(TCNQ)2 grown by different methods. Where, Ad and TCNQ are representing acridinium and tetracyanoquinodimethane. The single crystal of this complex shows DC conductivity at room temperature 100 ohm-1 cm-1 with activation energy 0.022 eV in the sample grown by electrochemical method. Whereas it is found 82 ohm-1 cm-1 with activation energy 0.03 eV for the sample grown by diffusion method. In all conductivity measurements, the observations are carried out along high conducting chain direction, which happens to be needle direction of the single crystal and known as principal axis direction.

Singh, Yadunath

2013-06-01

202

An ex vivo comparison of three different gutta-percha cones when compacted at different temperatures: rheological considerations in relation to the filling of lateral canals  

Microsoft Academic Search

Venturi M, Di Lenarda R, Breschi L. An ex vivo comparison of three different gutta-percha cones when compacted at different temperatures: rheological considerations in relation to the filling of lateral canals. International Endodontic Journal, 39, 648-656, 2006. Aim To compare ex vivo the penetration of three brands of gutta-percha cones, compacted under a constant force and heated to different temperatures,

M. Venturi; R. Di Lenarda; L. Breschi

2006-01-01

203

Combined effects of the herbicide terbuthylazine and temperature on different flagellates from the Northern Adriatic Sea.  

PubMed

The triazinic herbicide terbuthylazine (TBA) is becoming an emergent contaminant in Italian rivers and in coastal and groundwater. A preliminary analysis of the sensitivity of marine flagellates to TBA was performed by monitoring the photosynthetic efficiency of nine species (belonging to the Dinophyceae or Raphidophyceae class) isolated from the Adriatic Sea. Different sensitivity levels for each flagellate were observed and the most sensitive microalgae, based on PSII inhibition, were: Gonyaulax spinifera>Fibrocapsa japonica>Lingulodinium polyedrum while the most resistant were two species belonging to the Prorocentrum genus. Then the response of two microalgae to drivers, such as temperature and terbuthylazine, applied in combination was also investigated. Two potentially toxic flagellates, Prorocentrum minimum and G. spinifera, were exposed, under different temperature conditions (15, 20 and 25C), to TBA concentrations that did not completely affect PSII. For both flagellates, effects of TBA on algal growth, measured through cell density and carbon analysis, as well as on the photosynthetic activity are reported. All parameters analyzed showed a negative effect of TBA from the exponential phase. TBA effect on algal growth was significantly enhanced at the optimal temperature conditions (20 and 25C), while no difference between control and herbicide treatments were detected for G. spinifera grown at 15C, which represented a stress condition for this species. The maximum inhibition of photosynthetic efficiency was found at 20C for both organisms. Both flagellates increased cell carbon and nitrogen content in herbicide treatments compared to the control, except G. spinifera grown at 15C. Chlorophyll-a production was increased only in G. spinifera exposed to 5 ?g L(-1) of TBA and the effect was enhanced with the increase of temperature. Herbicide-induced variations in cellular components determined changes in cellular carbon:nitrogen (C:N) and chlorophyll:carbon (Chl:C) ratios. The C:N ratio decreased in both species, while only G. spinifera showed an increase in the Chl:C ratio at all temperature conditions. In response to TBA exposure G. spinifera increased extracellular polysaccharides release at 20 and 25C, while no difference was reported for P. minimum. Changes in nutrient uptake rates were also observed for P. minimum. Nitrate and phosphate uptake significantly increased in the presence of TBA and this response was enhanced at 25C, while nitrate uptake increased in G. spinifera only when grown at 25C. As for growth rates, the observed changes in intracellular component contents increased at optimal temperature conditions. In this work it is shown that temperature conditions can have an important role on the effect of terbuthylazine on algal growth and on the physiological responses of different species. Furthermore, the algal resistance and recovery can be dependent on nutrient availability. PMID:23280488

Fiori, Emanuela; Mazzotti, Matilde; Guerrini, Franca; Pistocchi, Rossella

2013-03-15

204

Survival kinetics of Listeria monocytogenes on raw sheep milk cured cheese under different storage temperatures.  

PubMed

Raw sheep milk cured cheese produced in the Castilla y Leon region (Spain) constitutes a traditional semi-hard aromatic cheese typically aged for three to six months. This product is catalogued as ready-to-eat since it is not submitted to any further treatment before consumption. Thus, foodborne pathogens such as Listeria monocytogenes can represent a health concern for susceptible consumers. This study was aimed at evaluating the survival of L. monocytogenes on raw sheep milk cured cheese under different storage temperatures. Log-linear+shoulder and Weibull type models were fitted to data observed in order to estimate kinetic parameters. The Arrhenius relationship was further used to predict the impact of temperature on L. monocytogenes behavior during storage at 4, 12 and 22C. Additionally, growth of lactic acid bacteria (LAB) as a representative group of the indigenous microbiota was evaluated. Results obtained indicated that the time to eradication (time when absence of L. monocytogenes in the analyzed samples was observed) was 114, 104, and 77days for cheese samples stored at 4, 12 and 22C, respectively. The LAB population showed an increase at 12 and 22C during storage. However, an increase of 1logCFU/g was observed during the first 2weeks irrespectively of the storage temperature. The log-linear+shoulder model indicated a good fit to observed data. Likewise, the Arrhenius relationship explained sufficiently the dependency of temperature on L. monocytogenes behavior. This study demonstrated that cheese storage at ambient temperatures could lead to the preservation of its quality properties as well as its safety against L. monocytogenes. PMID:24630556

Valero, Antonio; Hernandez, Marta; De Cesare, Alessandra; Manfreda, Gerardo; Gonzlez-Garca, Patricia; Rodrguez-Lzaro, David

2014-08-01

205

Life table of Tamarixia radiata (Hymenoptera: Eulophidae) on Diaphorina citri (Hemiptera: Psyllidae) at different temperatures.  

PubMed

Tamarixia radiata (Waterston, 1922) is the main parasitoid of Diaphorina citri (Kuwayama, 1907), and has been used in classical biological control programs in several countries. The current study investigated the biology and determined the fertility life table of T. radiata in different temperatures, to obtain information to support the establishment of a biological control program for D. citri in Brazil. Fifth-instar nymphs of D. citri were offered to females of T. radiata for parasitism, for 24 h. Then, the parasitoid was removed and the nymphs were placed in incubators at 15, 20, 25, 30, or 35 +/- 1 degrees C, 70 +/- 10% RH, and a 14-h photophase. The percentages of parasitism and emergence, the sex ratio, and the preimaginal period of T. radiata were determined. The fertility life table was developed from the biological data. The highest parasitism rate (77.24%) was obtained at a temperature of 26.3 degrees C, and the lowest parasitism rates occurred at 15 and 35 degrees C (23.1 and 40.2%, respectively). The highest percentages of emergence of the parasitoid occurred at 25, 30, and 35 degrees C (86.7, 88.3, and 78.8%, respectively), with the calculated peak at 30.8 degrees C (89.90%). The duration of the preimaginal developmental period for both females and males of T. radiata was inversely proportional to temperature in the thermal range of 15-35 degrees C. The development of T. radiata occurred at all temperatures studied, and the highest viability of the preimaginal period occurred at 25 degrees C. The highest values of net reproductive rate and finite growth ratio (lambda) were observed at 25 degrees C, so that in each generation the population of T. radiata increased 126.79 times, higher than the values obtained at the other temperatures. PMID:22606801

Gmez-Torres, Mariuxi Lorena; Nava, Dori Edson; Parra, Jos Roberto Postali

2012-04-01

206

Acute toxicity of arsenic under different temperatures and salinity conditions on the white shrimp Litopenaeus vannamei.  

PubMed

The aim of this study was to determine acute toxicity in the post larvae of the white shrimp Litopenaeus vannamei after 96h of exposure to dissolved arsenic under three different temperatures and salinity conditions. Recent reports have shown an increase in the presence of this metalloid in coastal waters, estuaries, and lagoons along the Mexican coast. The white shrimp stands out for its adaptability to temperature and salinity changes and for being the main product for many commercial fisheries; it has the highest volume of oceanic capture and production in Mexican shrimp farms. Lethal concentrations (LC50-96h) were obtained at nine different combinations (3??3 combinations in total) of temperature (20, 25, and 30C) and salinity (17, 25, and 33) showing mean LC50-96h values (standard error) of 9.13??0.76, 9.17??0.56, and 6.23??0.57mgAs?L(-1)(at 20C and 17, 25, and 33 salinity); 12.29??2.09, 8.70??0.82, and 8.03??0.59mgAs?L(-1) (at 25C and 17, 25, and 33 salinity); and 7.84??1.30, 8.49??1.40, and 7.54??0.51mgAs?L(-1) (at 30C and 17, 25, and 33 salinity), respectively. No significant differences were observed for the optimal temperature and isosmotic point of maintenance (25C-S 25) for the species, with respect to the other experimental conditions tested, except for at 20C-S 33, which was the most toxic. Toxicity under 20C-S 33 conditions was also higher than 25C-S 17 and 20C (S 17 or 25). The least toxic condition was 25C-S 17. All this suggests that the toxic effect of arsenic is not affected by temperature changes; it depends on the osmoregulatory pattern developed by the shrimp, either hyperosmotic at low salinity or hiposmotic at high salinity, as observed at least on the extreme salinity conditions here tested (17 and 33). However, further studies testing salinities near the isosmotic point (between 20 and 30 salinities) are needed to clarify these mechanisms. PMID:23471636

Valentino-lvarez, Jess Alberto; Nez-Nogueira, Gabriel; Fernndez-Bringas, Laura

2013-06-01

207

A comparative evaluation of wear of enamel caused by ceramics with different fusion temperatures.  

PubMed

Dental ceramics are the most used esthetic fixed Prosthodontic restorative material today. However, dentists remain suspicious about their potential abrasivity. Lower-fusing ceramic materials developed, are claimed to be wear friendly. This study was conducted to compare the wear of enamel of extracted teeth against one conventionally used ceramic VMK-95 (fusing temperature 930C) and two new lower-fusing ceramics-Omega 900 and Finesse with fusing temperatures 900 and 760C respectively, used for metal-ceramic restorations. Metal disks were prepared from ceramic alloy and divided into three groups of 10disks each on which VMK-95, Omega 900 and Finesse ceramics were applied respectively. Ceramic disks and tooth specimen were mounted on custom-made wear simulator and subjected to predefined masticatory test. Each tooth specimen was profiled by laser triangulation sensor before and after masticatory test. Difference in height was calculated. The results showed that mean loss of height of tooth was least against Finesse (0.3431+0.0177mm) followed by Omega 900 (0.4076+0.0135mm) and VMK-95 (0.6177+0.014mm). Statistical analysis revealed statistically significant difference between VMK-95 & Omega 900 and VMK-95 & Finesse. The difference in loss of height of tooth against Finesse & Omega 900 is statistically insignificant (P<0.001). The results of this study indicate that lower-fusing dental ceramics cause less wear of opposing enamel. PMID:24431784

Khandelwal, Meenakshi; Jain, Deshraj

2013-12-01

208

Length-Scale analysis of surface albedo, temperature, and normalized difference vegetation index in desert grassland  

NASA Astrophysics Data System (ADS)

The Jornada Experiment on the Jornada Experimental Range in southern New Mexico aims at the description of the surface energy balance of a desert grassland ecosystem. A large volume of both field and remote sensing data has been collected from 1995 to 1998. Airborne Daedalus scanner data with a spatial resolution of 4 m have been used to infer the following land surface characteristics: surface temperature, albedo, and normalized difference vegetation index (NDVI). These land surface characteristics can be used as input for land surface models. However, land surface models work with very coarse grid cells of at least 5050 km, in contrast to high-resolution remote sensing data. Also, land surface models are generally based on nonlinear algorithms. Both restrictions lead to scale problems. One apparent question is how to scale up input remote sensing data to the much coarser resolution of the land surface model. The first step is to derive the length scale of the input land surface characteristics. The length scales of the land surface characteristics have been determined with the following two techniques: autocorrelation and wavelet analysis. Within the Jornada Experimental Range, three different sites with different vegetation characteristics were distinguished: grass, shrub, and a transition site with patches of both grass and shrub. The autocorrelation and wavelet analysis showed similar results for the shrub site. For the grass and transition site the wavelet analysis underestimated the length scale of the surface albedo and temperature. The length scale of the surface albedo was 35, 33, and 10 m for grass, transition, and shrub sites, respectively. The length scale of the surface temperature was 31, 20, and 8 m for grass, transition, and shrub sites, respectively. The length scale of the NDVI was 12, 6, and 5 m for grass, transition, and shrub sites, respectively. These small length scales could hamper the use of low-resolution remote sensing data for deriving input data for land surface models.

Pelgrum, Henk; Schmugge, Tom; Rango, Al; Ritchie, Jerry; Kustas, Bill

2000-07-01

209

Charge-discharge characteristics of the mesocarbon microbeads heat-treated at different temperatures  

SciTech Connect

Mesocarbon microbeads (MCMB) is one of the promising carbon materials as anodes for rechargeable lithium batteries among commercially available carbon materials. have examined the correlation between carbon structures and charge-discharge characteristics of the MCMBs prepared at different heat-treatment temperatures. It was found that the MCMB heat-treated at 700 C possesses a tremendously high charge-discharge capacity of 750 Ah/kg. This suggests that there is another mechanism for the charge-discharge reaction besides a graphite intercalation compound mechanism which is well known. Therefore, the authors propose a cavity mechanism in which intercrystallite spaces in MCMB are capable of storing lithium species.

Mabuchi, Akihiro; Tokumitsu, Katsuhisa; Fujimoto, Hiroyuki; Kasuh, Takahiro [Osaka Gas Co., Osaka (Japan). Research and Development Center

1995-04-01

210

Magnetic piston model for higher ion charge and different electron and ion plasma temperatures  

SciTech Connect

A new formula for the magnetic piston model, which explicitly describes how the momentum imparted to the ions by the magnetic pressure depends not only on the ion mass but also on the ion charge, as well as, on the plasma electron and ion temperatures, is derived following Rosenbluth's classical particle-field self-consistent plane approximation analytic calculation. The formula presented in this paper has implications in explaining the experimentally observed separation of the ions of different species and charges by the magnetic field penetrating the plasma and specularly reflecting them.

Bogatu, I. N. [FAR-TECH, Inc., 10350 Science Center Drive, Bldg.14, Suite 150, San Diego, California 92121 (United States)] [FAR-TECH, Inc., 10350 Science Center Drive, Bldg.14, Suite 150, San Diego, California 92121 (United States)

2013-05-15

211

Electrical resistance of CNT-PEEK composites under compression at different temperatures  

PubMed Central

Electrically conductive polymers reinforced with carbon nanotubes (CNTs) have generated a great deal of scientific and industrial interest in the last few years. Advanced thermoplastic composites made of three different weight percentages (8%, 9%, and 10%) of multiwalled CNTs and polyether ether ketone (PEEK) were prepared by shear mixing process. The temperature- and pressure-dependent electrical resistance of these CNT-PEEK composites have been studied and presented in this paper. It has been found that electrical resistance decreases significantly with the application of heat and pressure.

2011-01-01

212

An investigation into the magnetic properties of Co-Cu nanoparticles at different temperatures  

NASA Astrophysics Data System (ADS)

This study employs molecular-dynamics simulations to predict the distribution function of diluted magnetic Co atoms in a Cu host and then uses the Weise mean-field theory and the Ruderman-Kittel-Kasuya-Yosida theory to calculate the magnetic properties of the Co-Cu alloys. Specifically, this study investigates the dependency of the nanoparticle magnetization on the Curie temperature for Co-Cu alloys with five different Co concentrations. The proposed method successfully overcomes the limitations of molecular-dynamics simulation in magnetic studies, for diluted systems at least.

Sun, Shih-Jye; Ju, Shin-Pon; Lo, Yu-Chieh; Lin, Jenn-Sen

2005-05-01

213

Electrical resistance of CNT-PEEK composites under compression at different temperatures  

NASA Astrophysics Data System (ADS)

Electrically conductive polymers reinforced with carbon nanotubes (CNTs) have generated a great deal of scientific and industrial interest in the last few years. Advanced thermoplastic composites made of three different weight percentages (8%, 9%, and 10%) of multiwalled CNTs and polyether ether ketone (PEEK) were prepared by shear mixing process. The temperature- and pressure-dependent electrical resistance of these CNT-PEEK composites have been studied and presented in this paper. It has been found that electrical resistance decreases significantly with the application of heat and pressure.

Mohiuddin, Mohammad; van Hoa, Suong

2011-06-01

214

Attainment of high sensitivity at elevated operating temperatures with staring hybrid HgCdTe-on-sapphire focal plane arrays  

NASA Astrophysics Data System (ADS)

Cost-effective high-performance IR imaging cameras need affordable staring focal plane arrays (FPAs) that can operate effectively at temperatures compatible with inexpensive long- life coolers. We report on staring hybrid 128 X 128 and 256 X 256 Hg1-xCdxTe FPAs that have requisite yield, sensitivity, operability, and reliability at a medium-wavelength IR (MWIR) cutoff wavelength ((lambda) c approximately 4.6 micrometers at 180 K) and elevated operating temperatures. Mean 256 X 256 FPA noise- equivalent temperature differences (NE(Delta) T) using broadband f/1.7 optics were 4.3, 7.7, and 55 mK at 120, 140, and 180 K, respectively. We extrapolate that camera NE(Delta) T

Kozlowski, Lester J.; McLevige, William V.; Cabelli, Scott A.; Vanderwyck, A. H.; Cooper, Donald E.; Blazejewski, Edward R.; Vural, Kadri; Tennant, William E.

1994-03-01

215

Thermoregulation in the cold after physical training at different ambient air temperatures.  

PubMed

Since human thermoregulation at rest is altered by cold exposure, it was hypothesized that physical training under cold conditions would alter thermoregulation. Three groups (n = 8) of male subjects (mean age 24.3 +/- 0.9 years) were evaluated: group T (interval training at 21 degrees C), group CT (interval training at 1 degrees C), and group C (no training, equivalent exposure to 1 degrees C). Each group was submitted, before and after 4 weeks of interval training (5 d/week), to a cold air test at rest (SCAT) (dry bulb temperature (Tdb) = 1 degrees C) for a 2-h period for evaluation of the thermoregulatory responses. During SCAT, after the training/acclimation period, group T exhibited a higher rectal temperature (Tre) (P < 0.05) without significant change in mean skin temperature (Tsk) whereas metabolic heat production (M) was higher at the beginning of the SCAT (P < 0.05). For group CT, no thermoregulatory change was observed. Group C showed a lower Tre (P < 0.05) without significant change in either Tsk or in M, suggesting the development of a hypothermic general cold adaptation. This study showed, first, that the cold thermoregulatory responses induced by an interval training differed following the climatic conditions of the training and, second, that this training performed in the cold prevented the development of a general cold adaptation. PMID:12430980

Launay, Jean-Claude; Besnard, Yves; Guinet, Anglique; Hanniquet, Anne-Marie; Bittel, Jacques; Savourey, Gustave

2002-09-01

216

Influence of different rubber dam application on intraoral temperature and relative humidity.  

PubMed

The purpose of this study was to investigate the effect of type of rubber dam and application method on the moisture exclusion effect. The intraoral temperature and relative humidity were compared among various moisture exclusion appliances. Various dry field techniques were applied to 5 subjects and intraoral temperature and relative humidity measured 5 min after placing a digital hygro-thermometer in the mouth. The relative humidity was 100% in all subjects when moisture was excluded by means of cotton rolls alone. When only tooth 36 was exposed, relative humidity was significantly lower with latex, urethane, or 3-dimensional sheets than with cotton rolls alone, and was similar to the level of humidity in the room. When a local rubber dam was used, the relative humidity was significantly higher than the indoor humidity (p<0.05). No significant differences were noted in the intraoral temperature or relative humidity between exposure of 4 teeth and 1 tooth, but variation in the relative humidity was more marked in 4- than in 1-tooth exposure. The creation of an air vent did not influence the moisture exclusion effect. These results suggest that the rubber dam isolation technique excludes moisture to a level equivalent to the humidity in the room when only a single tooth is exposed, but the moisture exclusion effect may be inconsistent when several teeth are exposed. PMID:24717925

Haruyama, Akiko; Kameyama, Atsushi; Tatsuta, Chihiro; Ishii, Kurumi; Sugiyama, Toshiko; Sugiyama, Setsuko; Takahashi, Toshiyuki

2014-01-01

217

Temperature dependence of the optical properties of VO2 deposited on sapphire with different orientations  

NASA Astrophysics Data System (ADS)

Vanadium dioxide exhibits a reversible first-order metal-insulator phase transition (MIT) at temperature TMIT= 350 K. The transformation brings structural phase transition and abrupt changes in electrical conductivity and optical properties. Despite intensive studies of this material, little is understood about the optical properties and their connection with the structural properties across the phase transition. We report spectroscopic ellipsometry and Raman investigations of the optical properties of vanadium dioxide on sapphire substrates with c-, m- and r- orientations. For the m- and r-plane substrates, VO2 is strained such that the material transforms from the monoclinic M1 phase directly to the rutile R structure. In contrast, c-plane sapphire produces strains favoring transformation from M1 into monoclinic M2 material, prior to reaching the R phase. These structural differences result in distinct variations of the optical transitions observed in the ellipsometry results. While in m-plane sample the energy gap collapses over a narrow temperature range, for the c-plane case, a broad temperature range is obtained over which the energy gap is small but not fully collapsed. Raman studies show diverse phonon behavior across the phase transitions.

Nazari, Mohammad; Zhao, Yong; Kuryatkov, Vladimir; Fan, Zhaoyang; Bernussi, Ayrton; Holtz, Mark

2012-10-01

218

Wear Mechanisms at High Temperatures. Part 1: Wear Mechanisms of Different Fe-Based Alloys at Elevated Temperatures  

Microsoft Academic Search

To extend the lifetime of the sinter grate used to crush the sinter cake into smaller pieces for steel fabrication, a study\\u000a was undertaken to investigate which wear processes are primarily responsible for limiting the lifetime of the sinter grate.\\u000a Several wear processes could be identified. The sinter temperature which is up to 800C causes temperature-induced material\\u000a ageing and oxidation.

H. Winkelmann; E. Badisch; M. Kirchganer; H. Danninger

2009-01-01

219

Effects of different surfaces on the transport and deposition of ruthenium oxides in high temperature air  

NASA Astrophysics Data System (ADS)

In order to understand the behaviour of ruthenium oxides in the reactor coolant system during an air ingress accident, new tests were performed in the frame of the RUSET (RUthenium Separate Effect Test) experimental program. These aimed to ascertain the effects of different surfaces (quartz, stainless steel (SS), zirconium alloy, alumina, oxidised metal, and surfaces with Mo or Cs deposits) on the transport and decomposition of ruthenium oxides in air stream along the temperature gradient zone (1100-100 C). The results demonstrated that the heterogeneous phase decomposition of RuO 3 and RuO 4 to RuO 2 is catalysed more efficiently by the quartz surface than by the SS or alumina surfaces. The presence of MoO 3 layers decreased the RuO x precipitation extent on all investigated surfaces. The trapping effect of Cs deposit on Ru in the temperature gradient zone was proved in the case of the SS surface. On the contrary, presence of Cs precipitate on alumina and especially on quartz surfaces was found to decrease their catalytic effect on the decomposition of ruthenium oxides, and thus increased the RuO 4 concentration in the outlet air. Similarly to the effect observed for Cs deposition, the presence of other fission products in the evaporation area (at 1100 C) decreased the partial pressure of RuO 4 in the outlet air at the SS surface and increased it at quartz and alumina surfaces. When zirconium (E110) cladding material was placed in the temperature gradient zone, no Ru transmittance occurred until the high temperature end of the zirconium tube was completely oxidised. After the intense oxidation of E110, Ru release occurred only in the presence of other fission product species. Pre-oxidation of SS surfaces in steam had no significant effect on the Ru passage.

Vr, N.; Matus, L.; Pintr, A.; Osn, J.; Hzer, Z.

2012-01-01

220

IAD of oxide coatings at low temperature: a comparison of processes based on different ion sources  

NASA Astrophysics Data System (ADS)

A comparative study of different ion and plasma assisted physical vapor deposition processes at low temperature is reported. To work out a clear comparison of the different processes, the object of the study are single layers of different metal oxides like Ta2O5, TiO2, SiO2 and mixed oxides like H4 (Merck) deposited on glass and silicon substrates. Three different types of ion- (or plasma-respectively) sources are used: the cold cathode ion source from Denton (CC 104), the end hall ion source Mark II from CSC and the advanced plasma source from Leybold. Each of these processes is run under conditions concerning process parameters like bias, ion current, ion energy, beam characteristics and gas flow, which were understood to be optimized also to maintain long-term stability as realistic production conditions. The resulting metal oxide single layers are characterized by their optical properties, dispersion curves for NUV and VIS as well as absorption and scatter at discrete wavelengths. Also discussed are mechanical properties like hardness and adherence. A test method is presented which clearly shows the superior behavior of the IAD coatings.

Niederwald, Hansjoerg S.; Kaiser, Norbert; Schallenberg, Uwe B.; Duparre, Angela; Ristau, Detlev; Kennedy, Michael

1997-10-01

221

Leaf senescence and grain filling affected by post-anthesis high temperatures in two different wheat cultivars  

Microsoft Academic Search

High temperature is a major factor affecting grain yield and plant senescence in wheat growing regions of central and east\\u000a China. In this study, two different wheat cultivars, Yangmai 9 with low-grain protein concentration and Xuzhou 26 with high-grain\\u000a protein concentration, were exposed to different temperature regimes in growth chambers during grain filling. Four day\\/night\\u000a temperature regimes of 34C\\/22C, 32C\\/24C,

Hui Zhao; Tingbo Dai; Qi Jing; Dong Jiang; Weixing Cao

2007-01-01

222

Temperature rating prediction of Tibetan robe ensemble based on different wearing ways.  

PubMed

Each piece of Western clothing has a unique temperature rating (TR); however, based on different wearing ways, one Tibetan robe ensemble can be used in various environments of the Tibetan plateau. To explain this environmental adaptation, thermal insulations and TR values of Tibetan robe ensembles in three typical wearing ways were measured by manikin testing and wearing trials, respectively. The TR prediction models for Tibetan robe ensembles were built in this research. The results showed that the thermal insulations of Tibetan robe ensembles changed from 0.26clo to 0.91clo; the corresponding TRs ranged from 9.90C to 16.86C because of different wearing ways. Not only the thermal insulation, but also the ways of wearing Tibetan robes was important to determining their TR values. The three TR models and a triangle area for each piece of Tibetan clothing explained its positive adaptation into the environment; this was different from the current TR models for Western clothing. PMID:22321946

Li, Jun; Guo, Xiaofang; Wang, Yunyi

2012-09-01

223

Gene and Protein Expression in Response to Different Growth Temperatures and Oxygen Availability in Burkholderia thailandensis  

PubMed Central

Burkholderia thailandensis, although normally avirulent for mammals, can infect macrophages in vitro and has occasionally been reported to cause pneumonia in humans. It is therefore used as a model organism for the human pathogen B. pseudomallei, to which it is closely related phylogenetically. We characterized the B. thailandensis clinical isolate CDC2721121 (BtCDC272) at the genome level and studied its response to environmental cues associated with human host colonization, namely, temperature and oxygen limitation. Effects of the different growth conditions on BtCDC272 were studied through whole genome transcription studies and analysis of proteins associated with the bacterial cell surface. We found that growth at 37C, compared to 28C, negatively affected cell motility and flagella production through a mechanism involving regulation of the flagellin-encoding fliC gene at the mRNA stability level. Growth in oxygen-limiting conditions, in contrast, stimulated various processes linked to virulence, such as lipopolysaccharide production and expression of genes encoding protein secretion systems. Consistent with these observations, BtCDC272 grown in oxygen limitation was more resistant to phagocytosis and strongly induced the production of inflammatory cytokines from murine macrophages. Our results suggest that, while temperature sensing is important for regulation of B. thailandensis cell motility, oxygen limitation has a deeper impact on its physiology and constitutes a crucial environmental signal for the production of virulence factors.

Peano, Clelia; Chiaramonte, Fabrizio; Motta, Sara; Pietrelli, Alessandro; Jaillon, Sebastien; Rossi, Elio; Consolandi, Clarissa; Champion, Olivia L.; Michell, Stephen L.; Freddi, Luca; Falciola, Luigi; Basilico, Fabrizio; Garlanda, Cecilia; Mauri, Pierluigi; De Bellis, Gianluca; Landini, Paolo

2014-01-01

224

Temperature dependence of the thermal conductivity of different forms of diamond  

NASA Astrophysics Data System (ADS)

We present a systematic theoretical investigation of the thermal conductivity of naturally abundant, isotopically enriched, fast neutron irradiated single crystals of diamond, and chemical vapor deposited diamond films of different types over a large temperature range. Existing experimental data have been analyzed using Callaway's theoretical model [Phys. Rev. 113, 1046 (1959)] for thermal conductivity based on an isotropic continuum phonon dispersion relation and using normal and umklapp phonon-phonon relaxation times derived from the application of time-dependent perturbation theory within an anharmonic continuum model. In contrast to existing theoretical studies of the thermal conductivity of diamond, our approach considers Grneisen's constant as the only (semi)adjustable parameter for anharmonic phonon interactions. This work quantifies the enhancement of the thermal conductivity of diamond with isotopic purity. This work also accounts for the dip in the thermal conductivity curve for hot filament chemical vapor deposition of diamond films and neutron irradiated diamond at low temperatures and provides an estimate of the amount, type, and size of defects present in such samples. We find that the N-drift term in Callaway's theory provides a significant contribution to the thermal conductivity of all the forms of diamond studied here.

Barman, Saswati; Srivastava, G. P.

2007-06-01

225

Gene and protein expression in response to different growth temperatures and oxygen availability in Burkholderia thailandensis.  

PubMed

Burkholderia thailandensis, although normally avirulent for mammals, can infect macrophages in vitro and has occasionally been reported to cause pneumonia in humans. It is therefore used as a model organism for the human pathogen B. pseudomallei, to which it is closely related phylogenetically. We characterized the B. thailandensis clinical isolate CDC2721121 (BtCDC272) at the genome level and studied its response to environmental cues associated with human host colonization, namely, temperature and oxygen limitation. Effects of the different growth conditions on BtCDC272 were studied through whole genome transcription studies and analysis of proteins associated with the bacterial cell surface. We found that growth at 37C, compared to 28C, negatively affected cell motility and flagella production through a mechanism involving regulation of the flagellin-encoding fliC gene at the mRNA stability level. Growth in oxygen-limiting conditions, in contrast, stimulated various processes linked to virulence, such as lipopolysaccharide production and expression of genes encoding protein secretion systems. Consistent with these observations, BtCDC272 grown in oxygen limitation was more resistant to phagocytosis and strongly induced the production of inflammatory cytokines from murine macrophages. Our results suggest that, while temperature sensing is important for regulation of B. thailandensis cell motility, oxygen limitation has a deeper impact on its physiology and constitutes a crucial environmental signal for the production of virulence factors. PMID:24671187

Peano, Clelia; Chiaramonte, Fabrizio; Motta, Sara; Pietrelli, Alessandro; Jaillon, Sebastien; Rossi, Elio; Consolandi, Clarissa; Champion, Olivia L; Michell, Stephen L; Freddi, Luca; Falciola, Luigi; Basilico, Fabrizio; Garlanda, Cecilia; Mauri, Pierluigi; De Bellis, Gianluca; Landini, Paolo

2014-01-01

226

Molecular Dynamics Simulation of the Fully Hydrated Dipalmitoylphosphatidylcholine (DPPC) Bilayer at Different Temperatures and Pressures  

NASA Astrophysics Data System (ADS)

The structural properties of lipid bilayers in biological membranes are of great interest in biochemistry, biophysics, and medicine. The main goal of this study is to use molecular dynamic (MD) techniques to investigate physical properties of the hydrated dipalmitoylphosphatidylcholine (DPPC) bilayer. The bilayer model consists of 25 DPPC molecules per each monolayer and 44.8% water by total weight. A modified version of AMBER MD suit of programs with CHARMM22 force field for phospholipids and the isothermal-isobaric or NPT ensemble with a fully flexible simulation box in ROAR program was used in this study. Simulations were performed under different pressure and temperature conditions. A liquid crystal phase (L?) is (experimentally) expected with the DPPC bilayer under 1 atm pressure and 323 K temperature conditions. However, area per lipid, bilayer thickness, chain tilt, and the order parameters resulting from the present simulation appeared to be more consistent with the known properties of the L?' phase. The results of the simulations will be discussed.

Lagowski, Jolanta B.; Wanasundara, Suranjith N.

2007-03-01

227

Influence of orientation on the size effect in BCC pillars with different critical temperatures.  

SciTech Connect

The size effect in body-centered cubic metals is comprehensively investigated through micro/nano-compression tests performed on focused ion beam machined tungsten (W), molybdenum (Mo) and niobium (Nb) pillars, with single slip [2 3 5] and multiple slip [0 0 1] orientations. The results demonstrate that the stress-strain response is unaffected by the number of activated slip systems, indicating that dislocation-dislocation interaction is not a dominant mechanism for the observed diameter dependent yield strength and strain hardening. Furthermore, the limited mobility of screw dislocations, which is different for each material at ambient temperature, acts as an additional strengthening mechanism leading to a material dependent size effect. Nominal values and diameter dependence of the flow stress significantly deviate from studies on face-centered cubic metals. This is demonstrated by the correlation of size dependence with the material specific critical temperature. Activation volumes were found to decrease with decreasing pillar diameter further indicating that the influence of the screw dislocations decreases with smaller pillar diameter.

Arzt, Eduard (INM - Leibniz Institute for New Materials and Saarland University, Saarbrucken, Germany); Gruber, Patrick A. (Karlsruhe Institute of Technology, Institut fur Zuverlassigkeit von Bauteilen und Systemen, Karlsruhe, Germany); Clark, Blythe G.; Frick, Carl P. (University of Wyoming, Laramie, WY); Schneider, Andreas S. (Max Planck Institute for Metals Research, Stuttgart, Germany)

2010-09-01

228

Histological features of respiratory epithelium of calves held at differing temperature and humidity.  

PubMed

The effect of ambient temperature and humidity on the structure of respiratory epithelium of calves was studied. Four calves of each of three experiments were acclimatized to a nonoperational environmental chamber for six days and then exposed to constant extremes of temperatures and relative humidity of one of 30 degrees C --35%, or 27 degrees C--92%, or 5 degrees C--92% respectively in this chamber for eight days each. Five calves (3 and 2) were similarly acclimatized then exposed to 1 degrees C--40%. Nasal swabs were taken from all animals at regular intervals. Swabs of three animals yielded Mycoplasma spp. and one swab yielded the virus of infectious bovine rhinotracheitis. Detailed histological studies of respiratory epithelium of nose, trachea, major bronchus and terminal bronchioli were conducted at four sites. Goblet cells were least in calves held in hot and dry air; calves held in dry air had the least polymorphonuclear cells and the greatest prevalence of hypochromatic cell layers and vacuolation of epithelial cells. Differences between experiments were evident most for sites of trachea and major bronchus. PMID:922554

Jericho, K W; Magwood, S E

1977-10-01

229

Differences and Similarities in MaCWAVE Summer and Winter Temperatures and Winds  

NASA Technical Reports Server (NTRS)

Small meteorological rockets released inflatable falling spheres during the MaCWAVE Campaign. The Mountain and Convective Waves Ascending Vertically Experiment (MaCWAVE) was carried out in two parts, a summer sequence from Andoya Rocket Range (69N) during July 2002 to examine convective initiation of gravity waves and a winter sequence from ESRANGE (68N) during January 2003 to examine mountain-terrain initiated gravity waves. The sphere-tracked data provided significant information about the variation of temperature and wind from 70 km and above. The changes observed may be considered akin to tidal motion; unfortunately the launch activity was restricted to 12-hour periods, thus the observation of a full diurnal cycle was not possible. During summer, temperature variation was smaller than that observed during winter when peak to null differences reached 15-20 K at 80-85 km. Variation in the zonal winds varied up to 100+mps in summer and winter. Examination of the times of peak wind vs altitude showed that the peak zonal wind occurred approximately two hours ahead of the peak meridional wind. We provide details about the measurements and observed variations.

Schmidlin, F. J.; Goldberg, R. A.

2008-01-01

230

Differences and Similarities between Summer and Winter Temperatures and Winds during MaCWAVE  

NASA Technical Reports Server (NTRS)

The Mountain and Convective Waves Ascending Vertically Experiment (MaCWAVE) was carried out in two sequences: one during the summer from the Andoya Rocket Range (69N) during July 2002 to examine convective initiation of gravity waves. The second was a winter sequence from ESRANGE (68N) during January 2003 to examine mountain-initiated waves. Inflatable falling spheres released from small meteorological rockets provided significant information about the variation of temperature and wind from 50 km and higher. The small rocket launch activity was restricted to 12-hour periods that inhibited observing a full diurnal cycle, nonetheless, the time-history of the measurements have provided information about tidal motion. During summer, temperature variation was smaller than observed during winter when peak differences reached 15-20 K at 80-85 km. variation in zonal winds varied up to more than 100 mps in summer and winter. Times of wind vs. altitude showed that the peak zonal component occurred approximately two hours ahead of the peak meridional wind. Measurement details and the observed variations are discussed.

Schmidlin, F. J.; Goldberg, R. A.

2008-01-01

231

Thermoregulation Responses of Broiler Chickens to Humidity at Different Ambient Temperatures. II. Four Weeks of Age  

Microsoft Academic Search

Twoexperimentswereconductedtoinves- tigate the effect of RH (35, 60, and 85%) on thermoregula- tion of broiler chickens at high (35C) and mild (30C) temperatures at the age of 4 wk. The effects of humidity on rectal temperature (RT) and plumage temperature at back (PBAT) and skin temperature at breast (SBRT) were determined at 1, 4, 8, 16, and 24 h after

H. Lin; H. F. Zhang; X. H. Gu; Z. Y. Zhang; J. Buyse; E. Decuypere

232

Rarefied Gas Flows Induced through a Pair of Parallel Meshes with Different Temperatures  

NASA Astrophysics Data System (ADS)

A simple method to form micro-channels that induce a rarefied gas flow by the effect of the temperature field is proposed. A pair of parallel wire meshes, one is heated and the other is unheated, induces a gas flow through the pair of meshes in the direction from unheated mesh to heated mesh. Three test devices with different diameters, 1 mm, 100 ?m, and 25 ?m, of the wire of the mesh, have been devised and the flow through the device is detected by a thin film or a small windmill for various pressures of the gas. The flow is observed in a range of the pressure where the mean free path of gas molecules is close to the scale of the mesh structure, e.g., the diameter of the wire. It is extended to a wider range of the pressure in the device using combined meshes consisting of coarser and finer mesh.

Sugimoto, H.; Kawakami, S.; Moriuchi, K.

2008-12-01

233

Widely tuned room temperature terahertz quantum cascade laser sources based on difference-frequency generation  

NASA Astrophysics Data System (ADS)

We demonstrate room temperature THz quantum cascade laser sources with a broad spectral coverage based on intracavity difference-frequency generation. Two mid-infrared active cores based on the single-phonon resonance scheme are designed with a THz nonlinearity specially optimized at the high operating fields that correspond to the highest mid-infrared output powers. A ?erenkov phase-matching scheme along with integrated dual-period distributed feedback gratings are used for efficient THz extraction and spectral purification. Single mode emissions from 1.0 to 4.6 THz with a side-mode suppression ratio and output power up to 40 dB and 32 ?W are obtained, respectively.

Lu, Q. Y.; Bandyopadhyay, N.; Slivken, S.; Bai, Y.; Razeghi, M.

2012-12-01

234

Determination of spectrum and different temperature of spontaneous chemiluminescence in rice seeds during early imbibition  

NASA Astrophysics Data System (ADS)

With high-sensitivity single-photon counter, spontaneous chemiluminescence (CL) spectrum and different temperature study on rice (Oryza sativa L.) seeds during early imbibition were carried out. The emission spectrum of whole rice seed, rice and coat had a greater proportion of red light during early imbibition. Comparing with spontaneous CL of barley (Hordeum vulgare L.) and soybean (Glycine max L. Merr) seeds, the spontaneous CL of rice seeds had a nonlinear, logarithmic-like increase of intensity in the T range 30-50C, the Van't Hoff coefficient Q10=IT+10/IT is equal to 2, which led us to the conclusion that spontaneous CL of rice seed during early imbibition partly came from enzyme catalyzing chemistry reaction.

Chen, WenLi; Xing, Da; Van Wijk, Roeland

2005-02-01

235

A multigrid method for natural convective heat transfer with large temperature differences  

NASA Astrophysics Data System (ADS)

Steady-state two-dimensional solutions to the full compressible Navier-Stokes equations are computed for laminar convective motion of a gas in a square cavity with large horizontal temperature differences. Results for air are presented. The ideal-gas law is used and viscosity is given by Sutherland's law. An accurate low-Mach number solver is developed. Hereby an explicit third-order discretization for the convective part and a line-implicit central discretization for the acoustic part and for the diffusive part are used. The semi-implicit line method is formulated in multistage form. Multigrid is used as acceleration technique. A convergence behaviour is obtained which is independent of grid size, grid aspect ratio, Mach number and Rayleigh number. Grid converged results are shown for Rayleigh numbers between 102 and 107.

Vierendeels, Jan; Merci, Bart; Dick, Erik

2004-07-01

236

Terahertz absorption spectrum of water vapor at different humidity at room temperature  

NASA Astrophysics Data System (ADS)

We measured the absorption spectrum of water vapor in 0.2-2.4THz range at different humidity from 17% to 98% at room temperature using Er: doped fiber laser (IMRA America Inc.) based terahertz time-domain spectroscopy. The experiments were performed in a nitrogen-purged cage at atmosphere environment to obtain the reference and water absorption information. The seventeen absorption lines were observed due to water molecular rotations in the ground vibration state. The first three absorption lines at low frequencies increase with humidity, following the Beer-Lambert Law, while some of high frequency lines were found to decrease with humidity. These effects will be discussed. The observed line broadening is due to collisions occurring among water and nitrogen molecules.

Xin, Xuying; Altan, Hakan; Matten, David; Saint, Angelamaria; Alfano, Robert

2006-03-01

237

Swelling behavior of a Chinese bituminous coal at different pyrolysis temperatures  

SciTech Connect

Pyrolysis experiments were performed in a drop tube furnace at 1373, 1523, and 1673 K to investigate the swelling behavior of a Chinese bituminous coal. Particle size distributions and morphologies of chars prepared from three size-classified fractions of the coal were analyzed by laser diffraction and SEM, respectively. The results show that significant swelling occurs during pyrolysis. It is found that both heating rate and particle size have important effects on coal swelling. For each size fraction used in the present study, the swelling ratio initially increases with increasing heating rate from 5 x 10{sup 3} to 2 x 10{sup 4} K/s, but then decreases when the heating rate further increases to 4 x 10{sup 4}K/s. A maximum swelling ratio is obtained at 2 x 10{sup 4} K/s for all coal samples, indicating that coal particles swell most at this heating rate. At the same temperature, the swelling ratios of the three size fractions are markedly different. It is shown that the finer the particle size, the higher is the swelling ratio. This is considered to be the result of the enrichment of vitrinite in small particles, as observed in this study, and the high volatile yields for them at elevated temperatures. It is also noted that the difference in swelling ratio diminishes with increasing particle size. The results also suggest that fragmentation observed in this study may contribute to reducing swelling ratio. Coal particles with a large size or undergoing a high heating rate have the tendency to fragment violently during pyrolysis, resulting in the decrease of their swelling ratios. 34 refs., 6 figs., 2 tabs.

Dunxi Yu; Minghou Xu; Yun Yu; Xiaowei Liu [Huazhong University of Science and Technology, Wuhan (China). State Key Laboratory of Coal Combustion

2005-12-01

238

Temperature adaptation in two bivalve species from different thermal habitats: energetics and remodelling of membrane lipids.  

PubMed

We compared lipid dynamics and the physiological responses of blue mussels Mytilus edulis, a cold-adapted species, and oysters Crassostrea virginica, a warmer-water species, during simulated overwintering and passage to spring conditions. To simulate overwintering, animals were held at 0 degrees C, 4 degrees C and 9 degrees C for 3 months and then gradually brought to and maintained at 20 degrees C for 5 weeks to simulate spring-summer conditions. Changes in lipid class and fatty acid composition were related to clearance rate and oxygen consumption. We found major differences between species in triglyceride (TAG) metabolism during overwintering. Mussels used digestive gland TAG stores for energy metabolism or reproductive processes during the winter, whereas oysters did not accumulate large TAG stores prior to overwintering. Mussel TAG contained high levels of 20:5n-3 compared to levels in oysters and in the diet. This may help to counteract the effect of low temperature by reducing the melting point of TAG and thus increasing the availability of storage fats at low temperature. Mussels seemed better able to mobilise 20:5n-3 and 18:4n-3 than other fatty acids. We also found that both bivalves underwent a major remodelling of membrane phospholipids. The unsaturation index decreased in the gills and digestive glands of both species during the early stages of warming, principally due to decreases in 22:6n-3 and 20:5n-3. In digestive glands, the unsaturation index did not increase with decreasing temperature beyond a threshold attained at 9 degrees C whereas a perfect negative relationship was observed in gills, as predicted by homeoviscous adaptation. The presence of digestive enzymes and acids in the digestive gland microenvironment may lead to specific requirements for membrane stability. That oysters had lower metabolic rates than mussels coincides with a lower unsaturation index of their lipids, as predicted by Hulbert's theory of membranes as metabolic pacemakers. Both species showed increased 20:4n-6 levels in their tissues as temperature rose, suggesting an increasing availability of this fatty acid for eicosanoid biosynthesis during stress responses. The contrast between the species in TAG dynamics and the similarity of their phospholipid remodelling emphasises the essential functional role of membrane phospholipid structure and the contrasting use of TAG by oysters and mussels during overwintering. PMID:17704075

Pernet, Fabrice; Tremblay, Rjean; Comeau, Luc; Guderley, Helga

2007-09-01

239

Amino acid contacts in proteins adapted to different temperatures: hydrophobic interactions and surface charges play a key role  

Microsoft Academic Search

Thermophiles, mesophiles, and psychrophiles have different amino acid frequencies in their proteins, probably because of the\\u000a way the species adapt to very different temperatures in their environment. In this paper, we analyse how contacts between\\u000a sidechains vary between homologous proteins from species that are adapted to different temperatures, but displaying relatively\\u000a high sequence similarity. We investigate whether specific contacts between

Gisle Slensminde; yvind Halskau Jr; Inge Jonassen

2009-01-01

240

Response of fish to different simulated rates of water temperature increase  

SciTech Connect

We initiated this study to define the limits of effluent-temperature rate increases during reactor restart, which will help minimize fish kills. We constructed an apparatus for exposing fish to various temperature-increase regimens and conducted two experiments based on information from system tests and scoping runs. In the rate experiment, we acclimated the fish to 20{degree}C, and then raised the temperature to 40{degree}C at varying rates. Because scoping runs and literature suggested that acclimation temperature may affect temperature-related mortality, we conducted an acclimation experiment. We acclimated the fish to various temperatures, then raised the temperatures to 39--40{degree}C at a rate of 2{degree}C every 12 hours. Based on the analysis of the data, we recommend temperature-increase rates during reactor restart of 2.5{degree}C every nine hours if ambient water temperatures are over 20{degree}C. If water temperatures are at or below 20{degree}C, we recommend temperature-increase rates of 2.5{degree}C every 12 hours. No regulation of temperature is required after effluent temperatures reach 40{degree}C. We recommend further studies, including expanded testing with the simulation system and behavioral and bioenergetic investigations that may further refine acceptable rates of effluent-temperature increases.

Wike, L.D.; Tuckfield, R.C.

1992-08-01

241

Characterization of different transitions in quantum dots-in-a-well (DWELL) infrared photodetectors  

NASA Astrophysics Data System (ADS)

Systematic characterization of various types of intersubband transitions in the quantum dots in a well (DWELL) infrared photodetectors has been presented. By changing the thickness of the quantum well, the excited state energy can be tuned with respect to the barrier, without altering the quantum dot ground state. Bound to continuum transitions offer very high extraction probability for photoexcited electrons but poor absorption coefficient, while the bound to bound transitions have higher absorption but poorer extraction probability. Bound to quasibound transition is optimum for intermediate values of electric fields with superior signal to noise ratio. The bound to quasibound device has the detectivity of 41011 cm.Hz1/2 W-1 (+3V, f /2 optics) at 77 K and 7.4108 cm.Hz1/2 W-1 at 200 K, which is highest reported detectivity at 200 K for detector with long wave cutoff wavelength. High performance focal plane arrays have been fabricated with noise equivalent temperature difference of 44 mK at 80 K for 6.1?m peak wavelength.

Barve, Ajit V.; Kim, Jun Oh; Sharma, Yagya D.; Rotter, Thomas; Sengupta, Saumya; Montoya, John; Krishna, Sanjay

2011-05-01

242

High temperature operation of quantum dots-in-a-well infrared photodetectors  

NASA Astrophysics Data System (ADS)

Systematic study of various types of intersubband transitions in the quantum dots-in-a-well (DWELL) infrared photodetectors has been presented. By changing the thickness of the quantum well, the excited state energy can be tuned with respect to the barrier, without altering the quantum dot ground state. Bound to continuum transitions offer very high extraction probability for photoexcited electrons but poor absorption coefficient, while the bound to bound transitions have higher absorption but poorer extraction probability. Bound to quasi-bound transition is optimum for intermediate values of electric fields with superior signal to noise ratio. The bound to quasi-bound device has the detectivity of 4 10 11 cm Hz 1/2 W -1 (+3 V, f/2 optics) at 77 K and 7.4 10 8 cm Hz 1/2 W -1 at 200 K, which is highest reported detectivity at 200 K for detector with long wave cutoff wavelength. High performance focal plane arrays have been fabricated with noise equivalent temperature difference of 44 mK at 80 K for 6.1 ?m peak wavelength.

Barve, Ajit V.; Montaya, John; Sharma, Yagya; Rotter, Thomas; Shao, Jiayi; Jang, Woo-Yong; Meesala, Srujan; Lee, Sang Jun; Krishna, Sanjay

2011-05-01

243

Comparative physiological and proteomic response to abrupt low temperature stress between two winter wheat cultivars differing in low temperature tolerance.  

PubMed

Abrupt temperature reduction in winter wheat at either autumn seedling stage prior to vernalisation or early spring crown stage can cause severe crop damage and reduce production. Many studies have reported the physiological and molecular mechanisms underlying cold acclimation in winter wheat by comparing it with spring wheat. However, processes associated with abrupt temperature reduction in autumn seedling stage prior to vernalisation in winter wheat are less understood. In this study, physiological and molecular responses of winter wheat seedlings to abrupt low temperature (LT) stress were characterised in the relatively LT-tolerant winter wheat cultivar Shixin 828 by comparing it with the relatively LT-sensitive cultivar Shiluan 02-1 using a combination of physiological, proteomics and biochemical approaches. Shixin 828 was tolerant to abrupt LT stress, while Shiluan 02-1 exhibited high levels of reactive oxygen species (ROS) and leaf cell death. Significant increases in relative abundance of antioxidant-related proteins were found in Shixin 828 leaves, which correlate with observed higher antioxidant enzyme activity in Shixin 828 compared to Shiluan 02-1. Proteomics analysis also indicated that carbohydrate metabolism-related proteins were more abundant in Shiluan 02-1, correlating with observed accumulation of soluble sugars in Shiluan 02-1 leaves. Amino acid analysis revealed a strong response to LT stress in wheat leaves. A negative effect of exogenous sucrose on LT tolerance was also found. This study indicates that high ROS scavenging capacity and high abundance of photosynthesis-related proteins might play a role in winter wheat response to abrupt LT stress. In contrast, excess accumulation of soluble sugars might be disadvantageous for LT tolerance in the wheat cultivar Shiluan 02-1. PMID:22963252

Xu, J; Li, Y; Sun, J; Du, L; Zhang, Y; Yu, Q; Liu, X

2013-03-01

244

Understanding Differences in Upper Stratospheric Ozone Response to Changes in Chlorine and Temperature as Computed Using CCMVal Models  

NASA Technical Reports Server (NTRS)

Projections of future ozone levels are made using models that couple a general circulation model with a representation of atmospheric photochemical processes, allowing interactions among photochemical processes, radiation, and dynamics. Such models are known as chemistry and climate models (CCMs). Although developed from common principles and subject to the same boundary conditions, simulated ozone time series vary for projections of changes in ozone depleting substances (ODSs) and greenhouse gases. In the upper stratosphere photochemical processes control ozone level, and ozone increases as ODSs decrease and temperature decreases due to greenhouse gas increase. Simulations agree broadly but there are quantitative differences in the sensitivity of ozone to chlorine and to temperature. We obtain insight into these differences in sensitivity by examining the relationship between the upper stratosphere annual cycle of ozone and temperature as produced by a suite of models. All simulations conform to expectation in that ozone is less sensitive to temperature when chlorine levels are highest because chlorine catalyzed loss is nearly independent of temperature. Differences in sensitivity are traced to differences in simulated temperature, ozone and reactive nitrogen when chlorine levels are close to background. This work shows that differences in the importance of specific processes underlie differences in simulated sensitivity of ozone to composition change. This suggests a) the multi-model mean is not a best estimate of the sensitivity of upper ozone to changes in ODSs and temperature; b) the spread of values is not an appropriate measure of uncertainty.

Douglass, A. R.; Stolarski, R. S.; Strahan, S. E.; Oman, L. D.

2012-01-01

245

Proportions of diether, macrocyclic diether, and tetraether lipids in Methanococcus jannaschii grown at different temperatures.  

PubMed Central

Growth of Methanococcus jannaschii over a wide temperature range (47 to 75 degrees C) is correlated with an ability to alter dramatically the proportions of three ether lipid cores. These lipids shifted from predominantly diether (2,3-di-O-phytanyl-sn-glycerol) at the lower growth temperatures to macrocyclic diether and tetraether at near optimal growth temperatures. Lipid head groups varied as well, especially with respect to an increase in phosphate at the higher temperatures. Images

Sprott, G D; Meloche, M; Richards, J C

1991-01-01

246

Tensile deformation mechanisms at different temperatures in the Ni-base superalloy GTD-111  

Microsoft Academic Search

The Ni-base superalloy GTD-111 is employed in high-power stationary gas turbines because of its high temperature strength and oxidation resistance. The temperature dependence of the tensile behavior of GTD-111 has been studied by tensile tests in the temperature range of 25900C with a constant strain rate of 10?4s?1. The results showed an abnormal tensile property variation with increasing temperature. The

Seyed Abdolkarim Sajjadi; Said Nategh; Mihaiela Isac; Seyed Mojtaba Zebarjad

2004-01-01

247

Role of temperature differences between surface and deep reservoirs in geyser dynamics: Insights from laboratory experiments  

NASA Astrophysics Data System (ADS)

Geysers are springs that produce episodic eruptions of steam, liquid water, and non-condensable gases. Their eruptions are smaller and more frequent than other eruptive processes (volcanic, or hydrothermal eruptions), providing a feasible natural laboratory to understand eruptive processes. Moreover, the fluid dynamics of geysers probe processes that operate in more inaccessible geothermal systems. We developed laboratory experiments to understand the role of the surface temperature on geyser dynamics. For the experimental model, we followed to model developed by Steinberg et al. (1982), which produced periodic eruptions. In this experimental model, eruptions are driven by the ascent of bubbles. The "explosive" ejection of fluid occurs when bubbles reach the surface of the conduit. The eruption of a bubble influences the nucleation on the next bubble through the pressure changes in the conduit. The experimental apparatus consists of a bottom reservoir and a vertical conduit that opens into an upper chamber that collects and returns liquid to the reservoir after the eruption. The reservoir was heated from below at a constant rate. The fluid used was Freon 113, which has a boiling point of 48C. Temperature in the upper part of the tube was varied between 0 to 20C. As we increase the temperature difference between the reservoir and the surface of the tube we find (1) that vapor contained in the upper part of bubble tends condense, impeding its ascent to the surface, (2) an increase the number of bubbles generated during the time between eruptions, (3) that the volume of vapor in the tube remain almost constant during the period between eruptions (4) an increase the frequency of eruptions, (5) an increase the escape speed of fluid from the tube, and (6) an increase in Reynolds number. We interpret these results in terms of heat transport by the rising bubbles. Bubbles transport the heat as latent heat of evaporation. Because the amount of heating was the same in all cases, to transport the same amount of heat with bubbles that tend to condense in the upper conduit, they must be generated more rapidly and hence eruptions occur more frequently. Even though, natural eruptive systems are much more complex that these experiments, our model allows us to study the coupling between bubble nucleation, bubble growth and ascent, and surface eruption. Reference: Steinberg, G.S., Merzhanov, G.S., and Steinberg, A.S. (1982) Geyser process: Theory, modeling, and field experiments. Part 3.Theory of the geyser process, Modern Geology, 8, 67-70.

Munoz Saez, C.; Shteinberg, A.; Manga, M.

2012-12-01

248

Growth and Chemical Composition of Spirulina Maxima and Spirulina Platensis Biomass at Different Temperatures  

Microsoft Academic Search

The influence of temperature on growth and biomass composition of two species of Spirulina, S. maxima and S. platensis used for food was studied. A 4L fermenter with temperature and agitation control was used to cultivate both species. Under continuous light, maximum cell production of 2.4 g l-1 was verified for both cultures studied at temperatures above 25 C: S.

M. A. C. L. de Oliveira; M. P. C. Monteiro; P. G. Robbs; S. G. F. Leite

1999-01-01

249

Validation and application of different experimental techniques to measure electronic component operating junction temperature  

Microsoft Academic Search

Increasing power densities and changing component design have brought about the need for accurate measurement of die junction temperature. While many junction temperature measurement techniques exist it is difficult to compare their relative performance. To validate the accuracy of various direct and indirect test methods, the operating junction temperature of board-mounted SO-16 and plastic quad flat packs (PQFP)-160 components has

John Lohan; Peter Rodgers; Carl-Magnus Fager; Reijo Lehtiniemi; V. Eveloy; P. Tulikka; J. Rantala

1999-01-01

250

Ultrafast temperature jump in polymers: Phonons and vibrations heat up at different rates  

Microsoft Academic Search

Optical calorimetry is used to study the dynamics of a polymer, poly-(methyl methylacrylate), (PMMA), subjected to a temperature jump which is faster than the time required for Boltzmann equilibrium. The temperature jump is produced by exciting a near-infrared dye embedded in the polymer with a 23 ps duration optical pulse. The magnitude of the temperature jump ?T was as large

Xiaoning Wen; William A. Tolbert; Dana D. Dlott

1993-01-01

251

Composition and Quality of Wheat Grown Under Different Shoot and Root Temperatures During Maturation  

Microsoft Academic Search

Cereal Chem. 79(3):397-403 Diminished quality of wheat (Triticum aestivum L.) from high temperature during maturation is usually attributed to direct effects of the stress on the shoots or grain. However, the upper soil temperature approaches the air temperature, and roots are highly sensitive and interact profoundly with other plant parts. The objective of this study was to determine the effect

Mohammed Guedira; Patrick J. McCluskey; Finlay MacRitchie; Gary M. Paulsen

2002-01-01

252

Temperature  

NSDL National Science Digital Library

Thermometers record the temperature in a given location. Temperature is a non-living thing because it doesn't physically move or eat, for example. However, temperature is a very important factor that effects where animals live and how long they stay in that particular spot.

Luis Miguel Orta Rial (None;)

2008-03-24

253

Effect of Different Arbuscular Mycorrhizal Fungi on Growth and Physiology of Maize at Ambient and Low Temperature Regimes  

PubMed Central

The effect of four different arbuscular mycorrhizal fungi (AMF) on the growth and lipid peroxidation, soluble sugar, proline contents, and antioxidant enzymes activities of Zea mays L. was studied in pot culture subjected to two temperature regimes. Maize plants were grown in pots filled with a mixture of sandy and black soil for 5 weeks, and then half of the plants were exposed to low temperature for 1 week while the rest of the plants were grown under ambient temperature and severed as control. Different AMF resulted in different root colonization and low temperature significantly decreased AM colonization. Low temperature remarkably decreased plant height and total dry weight but increased root dry weight and root-shoot ratio. The AM plants had higher proline content compared with the non-AM plants. The maize plants inoculated with Glomus etunicatum and G. intraradices had higher malondialdehyde and soluble sugar contents under low temperature condition. The activities of catalase (CAT) and peroxidase of AM inoculated maize were higher than those of non-AM ones. Low temperature noticeably decreased the activities of CAT. The results suggest that low temperature adversely affects maize physiology and AM symbiosis can improve maize seedlings tolerance to low temperature stress.

Chen, Xiaoying; Song, Fengbin; Liu, Fulai; Tian, Chunjie; Liu, Shengqun; Xu, Hongwen; Zhu, Xiancan

2014-01-01

254

Quality index chart for different alloys and temperatures: a case study on aluminium die-casting alloys  

Microsoft Academic Search

The possibility of developing an analytical quality index chart for applications above room temperature valid for different alloys is explored. The testing temperature and the chemical composition of the material are incorporated into the analysis through their respective effects on the material's strain hardening rate and yield strength. The resulting quality index chart has been used to compare the performance

C. H Cceres; M Makhlouf; D Apelian; L Wang

2001-01-01

255

Temperature evolution and mass losses during immersion vacuum cooling of cooked beef joints A finite difference model  

Microsoft Academic Search

A finite difference model was developed to describe and predict the temperature and mass loss evolution in reconstructed beef joints during immersion vacuum cooling. Fast cooling is obtained within beef pores and at beef surface when evaporation in the surrounding liquid is high. The cooling rate diminishes as the vacuum chamber pressure stabilizes and the liquid temperature reaches its lower

Liana Drummond; Da-Wen Sun

2008-01-01

256

Effects of rapid temperature changes on HK, PK and HSP70 of Litopenaeus vannamei in different seasons  

NASA Astrophysics Data System (ADS)

Activities of hexokinase (HK), pyruvate kinase (PK) and levels of HSP70 were measured to evaluate the response of Litopenaeus vannamei to rapid temperature changes under controlled laboratory conditions. Shrimps were subjected to a quick temperature change from 27C to 17C for the summer case (Cold temperature treatment), or from 17C to 27C for the winter case (Warm temperature treatment). After 0.5, 1, 3, 6, 12, 24, 48, and 72 h of exposure time, shrimps were sampled and prepared for further analysis. The results showed that the effect of acute temperature changes on activities of HK was significant. Patterns of variations of the two glycolytic enzymes suggested that enzymes in the glycolysis cycle could adjust their activities to meet the acute temperature change. The HSP70 level increased in both cold and warm temperature treatments, suggesting that the rapid temperature changes activated the process of bodys self-protection. But the difference in expression peak of HSP70 might be related to the different body size and the higher thermal sensitivity to temperature increase than to temperature decrease of L. vannamei.

Guo, Biao; Wang, Fang; Dong, Shuanglin; Hou, Chunqiang

2010-09-01

257

Laboratory Measurements of the Ozone Absorption Coefficient in the Wavelength Region 339 to 362 nm at Different Temperatures.  

National Technical Information Service (NTIS)

Instrumentation for the absolute measurement of the ozone absorption coefficient in the Huggins bands at different temperatures was set up. Ozone is produced with an electrical discharge and stored cryogenically; differential absorption measurements are c...

M. Cacciani A. Disarra G. Fiocco

1987-01-01

258

Fault current limiter based on high temperature superconductors - different concepts, test results, simulations, applications  

NASA Astrophysics Data System (ADS)

All electric equipment in a power system has to be designed to withstand the mechanical and thermal stresses of potential short-circuit currents. Any reduction of these currents can lead to significant cost savings. Among all current limiting devices, superconducting fault current limiters (SCFCL) offer ideal performance: in normal operation the SCFCL is in its superconducting state and has negligible impedance, in the event of a fault, the transition into the normal conducting state passively limits the current. Different high temperature superconductors (HTS) materials, like YBCO films, Bi2223 wires or Bi2212 bulk are under development for the use in SCFCL. Due to the brittle nature of HTS and the hot-spot problem, most HTS components for current limitation are composites comprising the HTS, a mechanical substrate or support, and an electrical bypass. The performance of the composites largely depend on the parameters: critical current density, I- V characteristics, thermal conductivity, thermal mass, and electrical bypass. Mainly two different concepts of SCFCL, namely, the resistive and the shielded core concept have been pursued in the past. In 1996 the first ever SCFCL was installed in a hydro-power plant. The device had a rated power of 1.2 MVA, it was of the shielded core type and was based on tubes of Bi2212-bulk material. The feasibility of the technology has been demonstrated in a one-year-endurance test. Recently more compact resistive SCFCLs based on the same Bi2212-bulk material have been developed. Theoretical models for the SCFCL show good agreement with experimental data. They are used to study the influence of SCFCLs in power systems in order to evaluate technical and economical advantages.

Paul, W.; Chen, M.; Lakner, M.; Rhyner, J.; Braun, D.; Lanz, W.

2001-05-01

259

Characterization of precursors of methanol synthesis catalysts, copper\\/zinc\\/aluminum oxides, precipitated at different pHs and temperatures  

Microsoft Academic Search

Catalyst precursors for copper\\/zinc aluminum mixed oxide catalysts with an atomic ratio of 6\\/3\\/1 were prepared by co-current precipitation at different pH levels and different temperatures. The precursors, catalysts and reduced catalysts were characterized by means of infrared spectroscopy, X-ray diffraction, thermal analysis, temperature-programmed oxidation and BET surface measurements. The catalysts were also tested for methanol synthesis activity in a

J.-L. Li; T. Inui

1996-01-01

260

High temperature effects on photosynthetic activity of two tomato cultivars with different heat susceptibility.  

PubMed

The functional activities of the photosynthetic apparatus of two tomato cultivars of different thermotolerance were investigated after a short period of high temperature treatment. Seedlings of two tomato genotypes, Lycopersicon esculentum var. Campbell-28 and the wild thermotolerant Nagcarlang, were grown under a photoperiod of 16h at 25 degrees C and dark period of 8h at 20 degrees C. At the fourth true leaf stage, a group of plants was exposed to heat stress of 45 degrees C for 2 h. The heat shock treatment caused important reductions of the net photosynthetic rate (Pn) of Campbell-28 plants due to non-stomatal components. These non-stomatal effects were not evident in Nagcarlang-treated plants. This reduction in the CO2 assimilation rate observed in Campbell-28 was generated by affections in the Calvin cycle and also in the PSII functioning. No changes in these parameters were observed in the thermotolerant genotype after the stress. Injury to the plasma membrane because of the heat stress was evident only in the Campbell-28 genotype. Heat led to a sun-type adaptation response of the photosynthesis pigment apparatus for the Nagcarlang genotype, but not for Campbell-28, and thus an increase in chlorophyll a/b ratio and a decrease in chlorophyll/carotenoid ratio were shown in Nagcarlang stressed plants. PMID:15832680

Camejo, Daymi; Rodrguez, Pedro; Morales, Ma Angeles; Dell'Amico, Jos Miguel; Torrecillas, Arturo; Alarcn, Juan Jos

2005-03-01

261

Establishment of three francisella infections in zebrafish embryos at different temperatures.  

PubMed

Francisella spp. are facultative intracellular pathogens identified in increasingly diverse hosts, including mammals. F. noatunensis subsp. orientalis and F. noatunensis subsp. noatunensis infect fish inhabiting warm and cold waters, respectively, while F. tularensis subsp. novicida is highly infectious for mice and has been widely used as a model for the human pathogen F. tularensis. Here, we established zebrafish embryo infection models of fluorescently labeled F. noatunensis subsp. noatunensis, F. noatunensis subsp. orientalis, and F. tularensis subsp. novicida at 22, 28, and 32C, respectively. All infections led to significant bacterial growth, as shown by reverse transcription-quantitative PCR (RT-qPCR), and to a robust proinflammatory immune response, dominated by increased transcription of tumor necrosis factor alpha (TNF-?) and interleukin-1? (IL-1?). F. noatunensis subsp. orientalis was the most virulent, F. noatunensis subsp. noatunensis caused chronic infection, and F. tularensis subsp. novicida showed moderate virulence and led to formation of relatively small granuloma-like structures. The use of transgenic zebrafish strains with enhanced green fluorescent protein (EGFP)-labeled immune cells revealed their detailed interactions with Francisella species. All three strains entered preferentially into macrophages, which eventually assembled into granuloma-like structures. Entry into neutrophils was also observed, though the efficiency of this event depended on the route of infection. The results demonstrate the usefulness of the zebrafish embryo model for studying infections caused by different Francisella species at a wide range of temperatures and highlight their interactions with immune cells. PMID:24614659

Brudal, Espen; Ulanova, Lilia S; O Lampe, Elisabeth; Rishovd, Anne-Lise; Griffiths, Gareth; Winther-Larsen, Hanne C

2014-06-01

262

CO{sub 2}-gasification reactivity of different carbonaceous materials at elevated temperatures  

SciTech Connect

At the atmospheric pressure and at the temperatures between 1,223 and 1,673 K, the CO{sub 2} gasification reactivity of seven different carbonaceous materials comprising coal tar pitch coke, petroleum coke, natural graphite, carbon black and three coal chars was investigated by using thermogravimetric analysis. Their crystalline structures were analyzed by X-ray diffraction (XRD). It is found that the reactivity of the chars, pitch coke and petroleum coke produced from liquid phase carbonization, is several times poorer than that of the coal chars produced from solid phase carbonization and even lower than that of natural graphite. At the same time, it is obtained that under the condition of the chemical reaction control, the apparent activation energies of the former are in the range of 135.82-174.92 kJ/mol, while those of the latter are between 89.95 kJ/mol and 110.05 kJ/mol. Besides, the reactivity of the sample has a certain correlation with the crystalline structure of the sample, i.e., the larger the fraction of the relatively better crystalline structure is, the poorer the reactivity of the sample is.

Gu, J.; Wu, S.; Wu, Y.; Gao, J. [East China University of Science and Technology, Shanghai (China)

2009-07-01

263

Detection of significant differences between absorption spectra of neutral helium and low temperature photoionized helium plasmas  

SciTech Connect

In this work, spectral investigations of photoionized He plasmas were performed. The photoionized plasmas were created by irradiation of helium stream, with intense pulses from laser-plasma extreme ultraviolet (EUV) source. The EUV source was based on a double-stream Xe/Ne gas-puff target irradiated with 10 ns/10 J Nd:YAG laser pulses. The most intense emission from the source spanned a relatively narrow spectral region below 20 nm, however, spectrally integrated intensity at longer wavelengths was also significant. The EUV radiation was focused onto a gas stream, injected into a vacuum chamber synchronously with the EUV pulse. The long-wavelength part of the EUV radiation was used for backlighting of the photoionized plasmas to obtain absorption spectra. Both emission and absorption spectra in the EUV range were investigated. Significant differences between absorption spectra acquired for neutral helium and low temperature photoionized plasmas were demonstrated for the first time. Strong increase of intensities and spectral widths of absorption lines, together with a red shift of the K-edge, was shown.

Bartnik, A.; Wachulak, P.; Fiedorowicz, H.; Fok, T.; Jarocki, R.; Szczurek, M. [Institute of Optoelectronics, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland)] [Institute of Optoelectronics, Military University of Technology, Kaliskiego 2, 00-908 Warsaw (Poland)

2013-11-15

264

Internal neutronics-temperature coupling in Serpent 2 - Reactivity differences resulting from choice of material property correlations  

SciTech Connect

This paper describes the unique way of simultaneously solving the power and temperature distributions of a nuclear system with the Monte Carlo neutron transport code Serpent 2. The coupled solution is achieved through the implementation of an internal temperature solver and material property correlations in the code. The program structure is reviewed concerning the temperature solver and the internal correlations as well as the internal coupling between these two and the neutron transport part. To estimate the reactivity differences resulting from correlation choices a simple pin-cell case has been calculated. It is established, that some correlation choices may result in difference in reactivity of approximately 100 pcm. (authors)

Valtavirta, V. [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT (Finland)] [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT (Finland)

2013-07-01

265

Temperature sensitivity of greenhouse gas production in wetland soils of different vegetation  

Microsoft Academic Search

Organic matter decomposition regulates rates of carbon loss (CO2 and CH4) in wetlands and has implications for carbon sequestration in the context of changing global temperature. Here we determined\\u000a the influence of temperature and vegetation type on both aerobic and anaerobic decomposition of organic matter in subtropical\\u000a wetland soils. As in many other studies, increased temperature resulted in higher rates

K. S. Inglett; P. W. Inglett; K. R. Reddy; T. Z. Osborne

266

Fabrication and characterisation of thin low-temperature MBE-compatible silicon oxides of different stoichiometry  

Microsoft Academic Search

We developed and tested three MBE-compatible processes for the deposition of high-quality low-temperature silicon oxides and oxynitrides in the ultra high vacuum at substrate temperatures between room temperature and 500C: gas enhanced evaporation (GEE), plasma enhanced evaporation (PEE) and plasma enhanced oxidation (PEO). The deposited layers were thoroughly investigated and compared with respect to their electrical, optical and stoichiometrical properties

A. Strass; P. Bieringer; W. Hansch; V. Fuenzalida; A. Alvarez; J. Luna; I. Martil; F. L. Martinez; I. Eisele

1999-01-01

267

An influence of ethanol and temperature on products formation by different preparations of Zymomonas mobilis extracellular levansucrase.  

PubMed

The ethanol and temperature effects on the ratio between Zymomonas mobilis 113S extracellular levansucrase activities were studied using fermentation broth supernatant, "levan-levansucrase" sediment precipitated by ethanol and highly purified enzyme. The fructooligosaccharide (FOS) production at different temperatures in the presence of ethanol was investigated. An ethanol increases FOS biosynthesis activity part of levansucrase. Especially, this effect was pronounced at lower temperatures (35-40 C) and using purified levansucrase. The inverse relationship between temperature and ratio synthetic activity/total activity of levansucrase was found. The FOS composition containing mostly 1-kestose, 6-kestose, and neokestose obtained in the presence of different ethanol concentrations was found relative constant, while the changes in the sucrose concentration and temperature gave slight changes in the ratio between 1-kestose and 6-kestose. PMID:22826021

Vigants, A; Upite, D; Scherbaka, R; Lukjanenko, J; Ionina, R

2013-01-01

268

Temperature coefficients of monolithic III-V triple-junction solar cells under different spectra and irradiance levels  

NASA Astrophysics Data System (ADS)

A complete set of temperature coefficients determined under controlled laboratory conditions is reported for a lattice-matched Ga0.50In0.50P/Ga0.99In0.01As/Ge and metamorphic (MM) Ga0.35In0.65P/Ga0.83In0.17As/Ge triple-junction solar cell. The cells have been investigated at one sun condition at different temperatures and spectra in order to identify a possible influence of the spectrum on the temperature coefficients. At the same time, the cells have been investigated at different temperatures and concentration levels to study the behaviour of the temperature coefficients under concentration.

Fernndez, E. F.; Siefer, G.; Schachtner, M.; Garca Loureiro, A. J.; Prez-Higueras, P.

2012-10-01

269

First difference method: Maximizing station density for the calculation of long-term global temperature change  

Microsoft Academic Search

The calculation of global land surface air temperature trends using the instrumental record has been based primarily upon two methods of maximizing the availability of station records. Hansen and Lebedeff( 1987) developed a technique that is still used today, known as the reference station method; Jones et al. (1986a) popularized the climate anomaly method in their calculations of global temperature

Thomas C. Peterson; Thomas R. Karl; Paul F. Jamason; Richard Knight; David R. Easterling

1998-01-01

270

Changes in starch and soluble sugar concentrations in winter squash mesocarp during storage at different temperatures  

Microsoft Academic Search

The effects of storage at 5, 10 or 15C for 6 months on the concentrations of starch and soluble sugar in winter squash (Cucurbita maxima Duch.) cultivar TC2A fruits were examined. Starch contents were significantly lower at 15C than at the other temperatures, although concentrations decreased throughout the storage period at all temperatures. Total soluble sugar contents increased during the

Daisuke Kami; Takato Muro; Keita Sugiyama

2011-01-01

271

Simple model for 10 cm soil temperature in different soils with short grass  

Microsoft Academic Search

Information on soil temperature, which e.g. governs soil nitrogen turnover and emergence of crops, is not routinely available from meteorological stations and is rather costly to obtain at field level from automated measurements or calculations with physically based models. The present study presents empirical and simple models for soil temperature at 10 cm depth in grass-covered soils. The global model

Finn Plauborg

2002-01-01

272

NOTES ON THE BEHAVIOR OF CARBON-STEEL IN MELTED LITHIUM AT DIFFERENT TEMPERATURES  

Microsoft Academic Search

The behavior of a plain carbon steel in contact with molten lithium at ; temperatures from 700 to 1000 deg C during various periods is considered. The ; following two facts are emphasized: the existence of a critical temperature at ; which the phenomenon of intergranular penetration and attack is particularly ; intense; considerable increase in the size of ferritic

P. Spinedi; U. Bernabai

1961-01-01

273

Mechanical Performance of Hemp Fiber Polypropylene Composites at Different Operating Temperatures  

Microsoft Academic Search

In order to quantify the effect of temperature on the mechanical properties of hemp fiber polypropylene composites, formulations containing 25% and 40% (by weight) hemp fiber were produced and tested at three representative temperatures of 256, 296, and 336 K. Flexural, tensile, and impact tests, as well as dynamic mechanical analysis, were performed and the reduction in mechanical properties were

MEHDI TAJVIDI; NAZANIN MOTIE; GHONCHE RASSAM; ROBERT H. FALK; COLIN FELTON

2009-01-01

274

Long-term water temperature reconstructions from mountain lakes with different catchment and morphometric features  

PubMed Central

Long-term water temperature records are necessary for better understanding climate change impacts on freshwaters. We reconstruct summer water temperatures from three climatically sensitive mountain lakes in Austria using paleolimnological methods aiming to examine long-term thermal dynamics and lakes' responses to regional climate variability since the Little Ice Age. Our results indicate divergent trends for the lakes. In two of the lakes, which are located at the sunny southern slope of mountains, water temperature has increased several degrees concurrent with the observed air temperature increase. In contrast, no change is observed in the reconstructed water temperatures of a shaded lake, located at the northern slope, where also the ecological and thermal changes are most subtle. The results indicate the importance of cold water inputs, such as snowmelt and groundwater, on lakes' thermal conditions and suggest that watershed characteristics and lake stratification play a major role in defining the lake-specific thermal regime.

Luoto, Tomi P.; Nevalainen, Liisa

2013-01-01

275

Long-term water temperature reconstructions from mountain lakes with different catchment and morphometric features.  

PubMed

Long-term water temperature records are necessary for better understanding climate change impacts on freshwaters. We reconstruct summer water temperatures from three climatically sensitive mountain lakes in Austria using paleolimnological methods aiming to examine long-term thermal dynamics and lakes' responses to regional climate variability since the Little Ice Age. Our results indicate divergent trends for the lakes. In two of the lakes, which are located at the sunny southern slope of mountains, water temperature has increased several degrees concurrent with the observed air temperature increase. In contrast, no change is observed in the reconstructed water temperatures of a shaded lake, located at the northern slope, where also the ecological and thermal changes are most subtle. The results indicate the importance of cold water inputs, such as snowmelt and groundwater, on lakes' thermal conditions and suggest that watershed characteristics and lake stratification play a major role in defining the lake-specific thermal regime. PMID:23965988

Luoto, Tomi P; Nevalainen, Liisa

2013-01-01

276

Fungal communities associated with the biodegradation of polyester polyurethane buried under compost at different temperatures.  

PubMed

Plastics play an essential role in the modern world due to their low cost and durability. However, accumulation of plastic waste in the environment causes wide-scale pollution with long-lasting effects, making plastic waste management expensive and problematic. Polyurethanes (PUs) are heteropolymers that made up ca. 7% of the total plastic production in Europe in 2011. Polyester PUs in particular have been extensively reported as susceptible to microbial biodegradation in the environment, particularly by fungi. In this study, we investigated the impact of composting on PUs, as composting is a microbially rich process that is increasingly being used for the processing of green waste and food waste as an economically viable alternative to landfill disposal. PU coupons were incubated for 12 weeks in fresh compost at 25C, 45C, and 50C to emulate the thermophilic and maturation stages of the composting process. Incubation at all temperatures caused significant physical deterioration of the polyester PU coupons and was associated with extensive fungal colonization. Terminal restriction fragment length polymorphism (TRFLP) analysis and pyrosequencing of the fungal communities on the PU surface and in the surrounding compost revealed that the population on the surface of PU was different from the surrounding compost community, suggesting enrichment and selection. The most dominant fungi identified from the surfaces of PU coupons by pyrosequencing was Fusarium solani at 25C, while at both 45C and 50C, Candida ethanolica was the dominant species. The results of this preliminary study suggest that the composting process has the potential to biodegrade PU waste if optimized further in the future. PMID:24056469

Zafar, Urooj; Houlden, Ashley; Robson, Geoffrey D

2013-12-01

277

Fungal Communities Associated with the Biodegradation of Polyester Polyurethane Buried under Compost at Different Temperatures  

PubMed Central

Plastics play an essential role in the modern world due to their low cost and durability. However, accumulation of plastic waste in the environment causes wide-scale pollution with long-lasting effects, making plastic waste management expensive and problematic. Polyurethanes (PUs) are heteropolymers that made up ca. 7% of the total plastic production in Europe in 2011. Polyester PUs in particular have been extensively reported as susceptible to microbial biodegradation in the environment, particularly by fungi. In this study, we investigated the impact of composting on PUs, as composting is a microbially rich process that is increasingly being used for the processing of green waste and food waste as an economically viable alternative to landfill disposal. PU coupons were incubated for 12 weeks in fresh compost at 25C, 45C, and 50C to emulate the thermophilic and maturation stages of the composting process. Incubation at all temperatures caused significant physical deterioration of the polyester PU coupons and was associated with extensive fungal colonization. Terminal restriction fragment length polymorphism (TRFLP) analysis and pyrosequencing of the fungal communities on the PU surface and in the surrounding compost revealed that the population on the surface of PU was different from the surrounding compost community, suggesting enrichment and selection. The most dominant fungi identified from the surfaces of PU coupons by pyrosequencing was Fusarium solani at 25C, while at both 45C and 50C, Candida ethanolica was the dominant species. The results of this preliminary study suggest that the composting process has the potential to biodegrade PU waste if optimized further in the future.

Zafar, Urooj; Houlden, Ashley

2013-01-01

278

Biofilm formation under different temperature conditions by a single genotype of persistent Listeria monocytogenes strains.  

PubMed

Some Listeria monocytogenes strains, termed persistent strains, originate from the same processing plant and have the ability to survive and grow over extended periods of time at contamination sources. In order to evaluate biofilm formation by such persistent strains, we isolated the pathogen from chicken samples collected from the same retail shop in repeated visits over 6 months. Strains that were of serotype 1/2b and were assigned to the same genotype by multi-virulence-locus sequence typing analysis were isolated on repeated occasions from December 1997 to June 1998 and thus were defined as persistent strains. In the present study, biofilm formation by the persistent strains was evaluated using microplates at 30 and 37C. The biofilm-forming capability was measured after cells attaching to the microplate well were stained with crystal violet. Comparison of biofilm formation at 30C among the persistent strains showed that a significantly higher amount of the stain was obtained from the persistent strains isolated from December to March than from those isolated from April to June. However, no significant difference in biofilm formation at 30C was observed between persistent and nonpersistent groups of L. monocytogenes strains. In contrast, biofilm formation at 37C was consistent among the persistent strains, and they produced significantly more biofilm at 37C than did the nonpersistent strains. The persistent strains were also found to change their biofilm-forming ability in a temperature-dependent manner, which may suggest that the persistent strains alter their biofilm formation in response to changing environmental factors. PMID:24406011

Ochiai, Yoshitsugu; Yamada, Fumiya; Mochizuki, Mariko; Takano, Takashi; Hondo, Ryo; Ueda, Fukiko

2014-01-01

279

Can we improve heterosis for root growth of maize by selecting parental inbred lines with different temperature behaviour?  

PubMed Central

Tolerance to high and low temperature is an important breeding aim for Central and Northern Europe, where temperature fluctuations are predicted to increase. However, the extent to which genotypes differ in their response to the whole range of possible temperatures is not well understood. We tested the hypothesis that the combination of maize (Zea mays L.) inbred lines with differing temperature optima for root growth would lead to superior hybrids. This hypothesis is based on the concept of marginal overdominance in which the hybrid expresses higher relative fitness than its parents, summed over all situations. The elongation rates of axile and lateral roots of the reciprocal cross between two flint and two dent inbred lines were assessed at temperatures between 15C and 40C. Indeed, the cross between UH005 and UH250 with lateral root growth temperature optima at 34C and 28C, respectively, resulted in intermediate hybrids. At temperatures below and above 31C, the hybrids' root growth was comparable to the better parent, respectively, thereby increasing temperature tolerance of the hybrid compared with its parents. The implications of and reasons for this heterosis effect are discussed in the context of breeding for abiotic stress tolerance and of putatively underlying molecular mechanisms. This finding paves the way for more detailed investigations of this phenomenon in future studies.

Hund, Andreas; Reimer, Regina; Stamp, Peter; Walter, Achim

2012-01-01

280

RR Lyrae pulsational temperature scales: on the consistency between different empirical relations  

NASA Astrophysics Data System (ADS)

In this paper, by assuming the equilibrium temperatures of RRab Lyrae variables defined by Carney, Storm & Jones as correct we show that temperatures derived from (B-V) colour (mean colour over the pulsational cycle calculated on the magnitude scale) transformations by Bessel, Castelli & Plez are consistent with the Carney et al. equilibrium temperatures within a probable error of ?logTe=+/-0.003. As a consequence, it is shown that the pulsational temperature scale temperature-period-blue amplitude [Teff=f(P,AB)] relation provided by De Santis, who studied the (B-V) colour of about 70 stars of Lub's sample, is a suitable relation, being reddening- and metallicity-free, to calculate equilibrium temperatures for RRab variables. This relation is independent of variable mass and luminosity within a large range of period-shift from the mean period-amplitude relation valid for Lub's sample of variables. On the contrary, it is also shown that a temperature-amplitude-metallicity relation is strictly dependent on the period-amplitude relation of the sample used for calibrating it: we prove that this means it is dependent on both the mass and luminosity variations of variables.

De Santis, Renato

2001-09-01

281

Optical properties and residual stress of YbF3 thin films deposited at different temperatures.  

PubMed

The influence of deposition temperature on the optical properties, microstructure, and residual stress of YbF(3) films, deposited by electron-beam evaporation, has been investigated. The increased refractive indices and surface roughness of YbF(3) films indicate that the film density and columnar structure size increase with deposition temperature. At the same time, higher packing density reduces absorption of moisture. The residual stress is related to deposition temperature and to substrate. For the samples deposited on BK7, the residual stress mainly comes from intrinsic stress, however, for those on fused silica, thermal stress is the dominant factor of total residual stress. PMID:18449267

Wang, Ying; Zhang, Yue-guang; Chen, Wei-lan; Shen, Wei-dong; Liu, Xu; Gu, Pei-fu

2008-05-01

282

Abrasive wear behavior of cast iron coatings plasma-sprayed at different mild steel substrate temperatures  

NASA Astrophysics Data System (ADS)

Three kinds of cast iron coatings were prepared by atmospheric plasma spraying. During the spraying, the mild steel substrate temperature was controlled to be averagely 50, 180, and 240C, respectively. Abrasive wear tests were conducted on the coatings under a dry friction condition. It is found that the abrasive wear resistance is enhanced with the substrate temperature increasing. SEM observations show that the wear losses of the coatings during the wear tests mainly result from the spalling of the splats. Furthermore, the improved wear resistance of the coatings mainly owes to the formation of oxides and the enhancement in the mechanical properties with the substrate temperature increasing.

Xing, Ya-zhe; Wei, Qiu-lan; Jiang, Chao-ping; Hao, Jian-min

2012-08-01

283

Physiological, Genetic and Proteomic Characterization of Arthrobacter Chlorophenolicus During Growth on Different Phenolic Substrates or Temperatures.  

National Technical Information Service (NTIS)

The species Arthrobacter chlorophenolicus was isolated from soil because of its ability to degrade high concentrations of 4-chlorophenol and other toxic aromatic compounds. It is also able to grow on and degrade phenolic compounds at low temperatures as w...

M. Unell

2008-01-01

284

Growth and biopigment accumulation of cyanobacterium Spirulina platensis at different light intensities and temperature  

PubMed Central

In order to find out optimum culture condition for algal growth, the effect of light irradiance and temperature on growth rate, biomass composition and pigment production of Spirulina platensis were studied in axenic batch cultures. Growth kinetics of cultures showed a wide range of temperature tolerance from 20 C to 40 C. Maximum growth rate, cell production with maximum accumulation of chlorophyll and phycobilliproteins were found at temperature 35 C and 2,000 lux light intensity. But with further increase in temperature and light intensity, reduction in growth rate was observed. Carotenoid content was found maximum at 3,500 lux. Improvement in the carotenoid content with increase in light intensity is an adaptive mechanism of cyanobacterium S.platensis for photoprotection, could be a good basis for the exploitation of microalgae as a source of biopigments.

Kumar, Manoj; Kulshreshtha, Jyoti; Singh, Gajendra Pal

2011-01-01

285

Temperature  

NSDL National Science Digital Library

This article discusses the relationship between temperature and heat and kinetic energy and it shows how to convert from degrees Fahrenheit to Centigrade. It also includes links to other resources, data, maps, and classroom activities.

2008-04-08

286

Modeling of soil C-dynamics reveals different carbon pool sizes and decomposition rates under varying incubation temperatures  

NASA Astrophysics Data System (ADS)

Soils contain about two thirds of all organic carbon that is stored in terrestrial ecosystems. Annual release of soil carbon (C) to the atmosphere currently exceeds the rate of anthropogenic CO2 emissions by a factor of 10 demonstrating that even small changes in soil C cycling are highly relevant to the global C cycle. Total soil organic matter consists of different C pools with intrinsic turnover rates ranging from less than a year to thousands of years. The objectives of this study were to model soil C-dynamics of a long-term incubation study (336 days, Conant et al. 2008) under two different incubation temperatures (25C and 35C) to obtain i) soil CO2-efflux rates, ii) C-dynamics and iii) temperature sensitivities of C-pools with different turnover times. Respiration rates and soil C-dynamics of three different C-pools were modeled by a 1st order differential equation and data assimilation techniques were used to optimize parameter estimation. All C of the most labile pool (fast turnover time) was respired within the first ten days of the incubation study and pool size as well as absolute decline of the labile C-pool did not differ between temperatures. The intermediate C-pool (intermediate turnover time) was initially 70% larger at the higher temperature but as C was respired at a higher rate the intermediate pool was of equal size at both temperatures after 336 days of incubation. The most recalcitrant C-pool (slow turnover time) declined very slowly over time at both temperatures. However, the contribution of the recalcitrant C-pool to the whole CO2-efflux became more important towards the end of the incubation study. A 10K higher incubation temperature resulted in a larger intermediate C-pool and therefore in twice as much C released. This modeling study shows that higher temperatures increase the amount of easily decomposable C and that C-pool sizes vary at different temperatures. These results are of particular interest for high latitude regions as temperatures are predicted to increase more rapidly in arctic ecosystems and strong effects of higher temperatures on permafrost C are to be expected.

Schdel, C.; Luo, Y.; Schuur, E. A.; Zhou, J.

2011-12-01

287

Uniaxial deformation behavior of different polypropylene cast films at temperatures near the melting point  

Microsoft Academic Search

A new apparatus for stretching polypropylenes at elevated temperatures below the melting point at high deformation speeds (up to 750 mm\\/s) is described. In the temperature range of 140-160 C the tensile behavior of polypropylene undergoes a shift from the ductile to the quasi-rubber-like deformation behavior. Furthermore, the deformation behavior is strongly affected by the strain rate. The homogeneity of

Stefan Rettenberger; Ludovic Capt; Helmut Mnstedt; Klaus Stopperka; Johannes Snze

2002-01-01

288

Breakdown characteristics of RTO 10 nm SiO2 films grown at different temperatures  

Microsoft Academic Search

Metal-oxide-semiconductor capacitors with 10 nm gate oxides grown by rapid thermal oxidation at temperatures of 1000, 1100 and 1150C have been electrically characterized by means of C-V techniques, time-zero and time-dependent breakdown experiments. The oxides grown at higher temperatures show superior interfacial and oxide integrity characteristics, which is consistent with a lower level of intrinsic stress in such layers. The

L. Fonseca; F. Campabadal

1994-01-01

289

Study of fracture mechanisms of a Ni-Base superalloy at different temperatures  

Microsoft Academic Search

Purpose: The Ni-base superalloy GTD-111 gains its appropriate microstructure and high temperature strength through precipitation hardening mechanism. Because of their service condition, tensile properties of the alloy have strong influence on stability and life of the blades. Design\\/methodology\\/approach: Tensile fracture mechanisms of the cast and heat treated superalloy were studied over a wide range of temperatures from 25 to 950C

S. A. Sajjadi; S. M. Zebarjad

290

Temperature imaging of laser-induced thermotherapy (LITT) by MRI: evaluation of different sequences in phantom.  

PubMed

The purpose of this study was to evaluate magnetic resonance (MR) temperature imaging of the laser-induced thermotherapy (LITT) comparing the proton resonance frequency (PRF) and T 1 thermometry methods. LITT was applied to a liver-mimicking acrylamide gel phantom. Temperature rise up to 70 C was measured using a MR-compatible fiber-optic thermometer. MR imaging was performed by a 1.5-T scanner utilizing fast gradient echo sequences including a segmented echo planar imaging (seg-EPI) sequence for PRF and the following sequences for T 1 method: fast low-angle shot (FLASH), inversion recovery turbo flash (IRTF), saturation recovery turbo flash (SRTF), and true fast imaging (TRUFI). Temperature-induced change of the pixel values in circular regions of interest, selected on images under the temperature probe tip, was recorded. For each sequence, a calibration constant could be determined to be -0.0088 0.0002 ppm C(-1) (EPI), -1.15 0.03 C(-1) (FLASH), -1.49 0.03 C(-1) (IRTF), -1.21 0.03 C(-1) (SRTF), and -2.52 0.12 C(-1) (TRUFI). These constants were evaluated in further LITT experiments in phantom comparing the calculated temperatures with the fiber optic-measured ones; temperature precisions of 0.60 C (EPI), 0.81 C (FLASH), 1.85 C (IRTF), 1.95 C (SRTF), and 3.36 C (TRUFI) were obtained. Furthermore, performing the Bland-Altman analysis, temperature accuracy was determined to be 0.23 C (EPI), 0.31 C (FLASH), 1.66 C (IRTF), 1.19 C (SRTF), and 3.20 C (TRUFI). In conclusion, the seg-EPI sequence was found to be more convenient for MR temperature imaging of LITT due to its relatively high precision and accuracy. Among the T 1 method sequences, FLASH showed the highest accuracy and robustness. PMID:23535892

Bazrafshan, Babak; Hbner, Frank; Farshid, Parviz; Hammerstingl, Renate; Paul, Jijo; Vogel, Vitali; Mntele, Werner; Vogl, Thomas J

2014-01-01

291

Microplasticity at room temperature of single-crystal titanium carbide with different stoichiometry  

Microsoft Academic Search

Single crystals of titanium carbide with a C-to-Ti range of 0.64 to 0.99 were plastically deformed at room temperature with a hardness indenter and a drill. The operating slip systems were determined by hardness anisotropy and transmission electron microscopy. The results were characteristic for bulk material deformation of TiC, below, as well as above, the brittle-to-ductile transition temperature. A typical

E. Breval

1981-01-01

292

The Viscosity at Different Temperatures of Soybean and Sunflower Biodiesels and Diesel Fuel Blends  

Microsoft Academic Search

In order to obtain viscosities of biodiesel fuels at a temperature range from 0 to 100C in the steps of 10C, DV-II+ Pro rotary viscosimeter from Brookfield Engineering Co., USA, was used and tests were performed at 20C ambient temperature. The viscosity measurements were made on a viscosimeter at a 100 rpm constant speed with PC control. The data with

F. Aksoy; ?. A. Baydir; H. Bayrakeken

2009-01-01

293

Grazer-induced colony formation in Scenedesmus acutus (Chlorophyceae): Ecomorph expression at different temperatures  

Microsoft Academic Search

Scenedesmus acutus Meyen was cultured at four temperatures (9.5 degrees, 16.5 degrees, 24 degrees, and 29 degrees C) in standard medium or in medium with filtered water from a Daphnia culture, Growth was significantly reduced at low temperatures. At 9.5 degrees C it took more than a week before formation of eight-celled coenobia occurred in both the absence and presence

M. F. L. L. W. Lrling; E. Van Donk

1999-01-01

294

Molecular analysis of the microbial community structures in water-flooding petroleum reservoirs with different temperatures  

NASA Astrophysics Data System (ADS)

Temperature is one of the most important environmental factors regulating the activity and determining the composition of the microbial community. Analysis of microbial communities from six water-flooding petroleum reservoirs at temperatures from 20 to 63 C by 16S rRNA gene clone libraries indicates the presence of physiologically diverse and temperature-dependent microorganisms in these subterrestrial ecosystems. In high-temperature petroleum reservoirs, most of the archaeal sequences belong to the thermophilic archaea including the genera Thermococcus, Methanothermobacter and Thermoplasmatales, most of the bacterial sequences belong to the phyla Firmicutes, Thermotogae and Thermodesulfobacteria; in low-temperature petroleum reservoirs, most of the archaeal sequences are affiliated with the genera Methanobacterium, Methanoculleus and Methanocalculus, most of the bacterial sequences to the phyla Proteobacteria, Bacteroidetes and Actinobacteria. Canonical correspondence analysis (CCA) revealed that temperature, mineralization, ionic type as well as volatile fatty acids showed correlation with the microbial community structures. These organisms may be adapted to the environmental conditions of these petroleum reservoirs over geologic time by metabolizing buried organic matter from the original deep subsurface environment and became the common inhabitants in subsurface environments.

Wang, L.-Y.; Duan, R.-Y.; Liu, J.-F.; Yang, S.-Z.; Gu, J.-D.; Mu, B.-Z.

2012-04-01

295

Difference in effect of temperature on absorption and Raman spectra between all-trans-?-carotene and all-trans-retinol  

NASA Astrophysics Data System (ADS)

Temperature dependencies (81 C-18 C) ofvisible absorption and Raman spectra of all-trans-?-carotene and all-trans-retinol extremely diluted in dimethyl sulfoxide are investigated in order to clarify temperature effects on different polyenes. Their absorption spectra are identified to be redshifted with temperature decreasing. Moreover, all-trans-?-carotene is more sensitive to temperature due to the presence of a longer length of conjugated system. The characteristic energy responsible for the conformational changes in all-trans-?-carotene is smaller than that in all-trans-retinol. Both of the Raman scattering cross sections increase with temperature decreasing. The results are explained with electronphonon coupling theory and coherent weakly damped electronlattice vibrations model.

Qu, Guan-Nan; Li, Shuo; Sun, Cheng-Lin; Liu, Tian-Yuan; Wu, Yong-Ling; Sun, Shang; Shan, Xiao-Ning; Men, Zhi-Wei; Chen, Wei; Li, Zuo-Wei; Gao, Shu-Qin

2012-12-01

296

Colour, myoglobin denaturation and storage stability of raw and cooked mutton chops at different end point cooking temperature.  

PubMed

In our study effect of different end point temperature (51C, 65C, 71C and 79C) on physicochemical and storage stability of mutton chops were evaluated. The L* (lightness) value and b* (yellowness) increased (P?temperature increased. As internal cooking temperature increased soluble myoglobin content decreased with a corresponding increase in percent myoglobin denatured. Raw mutton chops (uncooked) had lower level of oxidation (less TBA values) than cooked mutton irrespective of storage length. Initial APC of raw and cooked mutton chops ranged from log 1.75 to log 3.73 and was lower in higher end point cooking temperature. It can be concluded that as end point temperature increased, mutton chops appear less red and raw mutton had lower level of oxidation than cooked mutton chops. PMID:24803706

Sen, A R; Naveena, B M; Muthukumar, M; Vaithiyanathan, S

2014-05-01

297

The prepatent period and cercarial production of Schistosoma haematobium in Bulinus truncatus (Egyptian field strains) at different constant temperatures  

Microsoft Academic Search

The developmental time ofSchistosoma haematobium inBulinus truncatus snails (field strains) was determined in the laboratory at different constant temperatures between 18 and 32C. The basic relationship between the length of the minimum prepatent period (y, in days) and the temperature (x, in C) is given by the hyperbolic formulay=295\\/(x-15.3), 15.3 being the theoretical developmental null point and 295 the constant

W. Pfliiger; M. Z. Roushdy; M. El Emam

1984-01-01

298

Differences in the catalytic mechanisms of mesophilic and thermophilic indole-3-glycerol phosphate synthase enzymes at their adaptive temperatures  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Catalytic mechanisms of thermophilic-mesophilic enzymes may differ. Black-Right-Pointing-Pointer Product release is rate-determining for thermophilic IGPS at low temperatures. Black-Right-Pointing-Pointer But at higher temperatures, proton transfer from the general acid is rate-limiting. Black-Right-Pointing-Pointer Rate-determining step is different still for mesophilic IGPS. Black-Right-Pointing-Pointer Both chemical and physical steps of catalysis are important for temperature adaptation. -- Abstract: Thermophilic enzymes tend to be less catalytically-active at lower temperatures relative to their mesophilic counterparts, despite having very similar crystal structures. An often cited hypothesis for this general observation is that thermostable enzymes have evolved a more rigid tertiary structure in order to cope with their more extreme, natural environment, but they are also less flexible at lower temperatures, leading to their lower catalytic activity under mesophilic conditions. An alternative hypothesis, however, is that complementary thermophilic-mesophilic enzyme pairs simply operate through different evolutionary-optimized catalytic mechanisms. In this communication, we present evidence that while the steps of the catalytic mechanisms for mesophilic and thermophilic indole-3-glycerol phosphate synthase (IGPS) enzymes are fundamentally similar, the identity of the rate-determining step changes as a function of temperature. Our findings indicate that while product release is rate-determining at 25 Degree-Sign C for thermophilic IGPS, near its adaptive temperature (75 Degree-Sign C), a proton transfer event, involving a general acid, becomes rate-determining. The rate-determining steps for thermophilic and mesophilic IGPS enzymes are also different at their respective, adaptive temperatures with the mesophilic IGPS-catalyzed reaction being rate-limited before irreversible CO{sub 2} release, and the thermophilic IGPS-catalyzed reaction being rate limited afterwards.

Zaccardi, Margot J.; Mannweiler, Olga [Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 (United States)] [Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 (United States); Boehr, David D., E-mail: ddb12@psu.edu [Department of Chemistry, The Pennsylvania State University, University Park, PA 16802 (United States)

2012-02-10

299

Determination of shelf-life of homogenized apple-based beikost storage at different temperatures using Weibull hazard model  

Microsoft Academic Search

A shelf-life model based on the storage temperature was developed for a homogenized fruit-based baby food. Bottles of apple compote for infant feeding were collected from a food company and stored at three different temperatures (23, 30 and 37C) during 420 days. CIELAB color space parameters, vitamin C, 5-hydroxymethylfurfural were measured and sensory analysis (sensory attributes and overall acceptability) was

Manuel Angel Palazn; Daro Prez-Conesa; Pedro Abelln; Gaspar Ros; Fernando Romero; Mara Luisa Vidal

2009-01-01

300

In vitro analysis of human tooth pulp chamber temperature after low-intensity laser therapy at different power outputs  

Microsoft Academic Search

In vitro studies have provided conflicting evidence of temperature changes in the tooth pulp chamber after low-level laser\\u000a irradiation of the tooth surface. The present study was an in vitro evaluation of temperature increases in the human tooth\\u000a pulp chamber after diode laser irradiation (GaAlAs, ??=?808nm) using different power densities. Twelve human teeth (three\\u000a incisors, three canines, three premolars and

Mrcio de Alencar Mollo; Lucio Frigo; Giovani Marino Favero; Rodrigo lvaro Brando Lopes-Martins; Aldo Brugnera Junior

2011-01-01

301

Numerical study of flame spread in an n -heptane droplet array in different ambient temperature and microgravity conditions  

Microsoft Academic Search

Flame spread in an n-heptane droplet array under conditions of microgravity, different ambient temperatures, and droplet spacing is studied numerically.\\u000a The dimensionless distance, fuel type, and ambient temperature are characteristic parameters that could change the flame spread\\u000a modes. Variations of the droplet spacing change the amount of the gas fuel on the centerline of droplets, and the flame can\\u000a either

S. Ranjbaran; S. Tabejamaat

2011-01-01

302

A comparison of proline, thiol levels and GAPDH activity in cyanobacteria of different origins facing temperature-stress  

Microsoft Academic Search

Three cyanobacterial strains originating from different habitats were subjected to temperature shift exposures and monitored for levels of proline, thiol and activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Thermophile Mastigocladus laminosus (growth optimum, 40 C), raised the proline level 4.2-fold at low temperature (20 C), for the psychrophile Nostoc 593 (growth optimum, 20 C), it was raised 8-fold at 40 C while

A. P. Singh; R. K. Asthana; Aravind M. Kayastha; S. P. Singh

2005-01-01

303

Photosynthetic Potential and its Association with Lipid Peroxidation in Response to High Temperature at Different Leaf Ages in Maize  

Microsoft Academic Search

High temperature generally constrains plant growth and photosynthesis in many regions of the world; however, little is known\\u000a about how photosynthesis responds to high temperature with regard to different leaf ages. The synchronous changes in gas exchange\\u000a and chlorophyll fluorescence at three leaf age levels (just fully expanded, mature, and older leaves) of maize (Zea mays L.) were determined at

Zhenzhu Xu; Guangsheng Zhou; Guangxuan Han; Yijun Li

2011-01-01

304

Effect of Different Temperatures on Consumption of Two Spotted Mite, Tetranychus urticae, Eggs by the Predatory Thrips, Scolothrips longicornis  

PubMed Central

Environmental variables such as temperature are important factors affecting the efficacy of biological control agents. This study evaluated the predation rate of the predatory thrips Scolothrips longicornis Priesner (Thysanoptera: Thripidae) against the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) under laboratory conditions. Based on daily and total prey consumption of different life stages of S. longicornis on spider mite eggs at temperatures covering the range suitable for development and survival of the predator (15 C to 37 C, 60 10% RH, 16:8 L:D), there was a significant effect of temperature on prey consumption. The number of prey consumed daily by first and second instar larvae increased linearly with increasing temperature from 15 C to 37 C, whereas daily consumption of preovipositing and postovipositing females was uninfluenced by temperature. Lower temperature thresholds for consumption by first and second instar larvae of S. longicornis was estimated to be 6.8 0.04 C and 4.6 0.03 C, respectively. The daily consumption of ovipositing females followed a nonlinear pattern, with maximum daily predation estimated at 32.8 C. From the model used to describe consumption of ovipositing females, an upper threshold for consumption of 41.4 C was estimated. The performance of S. longicornis at the different temperatures is discussed in relation to its practical use in integrated pest control programs.

Pakyari, Hajar; Enkegaard, Annie

2012-01-01

305

Life tables and development of Amblyseius swirskii (Acari: Phytoseiidae) at different temperatures.  

PubMed

Development time, reproduction, survival and sex ratio were determined for the omnivorous mite Amblyseius swirskii at nine constant temperatures (13, 15, 18, 20, 25, 30, 32, 34 and 36C) on pepper leaf disks with cattail, Typha latifolia, pollen for food. These data were used to derive life table parameters at these constant temperatures. No development was observed at 13C. The lower development threshold, based on the fit to the linear portion of the development curve, was 11.3C. The upper development threshold was 37.41.12C, and the optimum temperature was calculated to be 31.5C. Average lifetime fecundity ranged from a low of 1.30.24eggs/female at 15C to a high of 16.10.34 eggs/female at 25C, and r (m) was greatest at 32C. Non-linear regression of the relationship between temperature and r (m) produced an estimate of 15.490.905C for the lower threshold for population growth and 36.990.816C for the upper threshold for population growth, and an optimum temperature of 30.1C. These values suggest that A. swiskii populations should grow quickly in response to food availability (pollen or prey) between 20 and 32C, but that, especially below 20C, population growth could be slow and impacts on prey populations should be monitored carefully. PMID:20628894

Lee, Heung-Su; Gillespie, David R

2011-01-01

306

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

PubMed

This study compared root surface temperatures produced during warm vertical obturation using the System B Heat Source (SB), the Touch 'n Heat device (TH), and a flame-heated carrier (FH). The root canals of 30 maxillary incisor, premolar, and mandibular incisor teeth were prepared; divided into three groups; and obturated using each heat source. A thermocouple placed 2 mm below the cementoenamel junction transferred the temperature rise on the external root surface to a digital thermometer. SB surface temperature rise was < 10 degrees C for all experimental teeth. TH temperature rise in maxillary incisors and premolars was < 10 degrees C; however, > 10 degrees C was observed for mandibular incisors. FH produced a > 10 degrees C surface temperature rise in all experimental teeth. The critical level of root surface heat required to produce irreversible bone damage is believed to be > 10 degrees C. The findings of this study suggest that warm vertical condensation with the SB should not damage supporting periradicular tissues. However, caution should be used with TH and FH on mandibular incisors. PMID:9922753

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

1998-09-01

307

Ambient temperature effect on single-bubble sonoluminescence in different concentrations of sulfuric acid solutions  

NASA Astrophysics Data System (ADS)

The effect of ambient temperature on the parameters of the single-bubble sonoluminescence in sulfuric acid (SA) diluted in water is studied. Using a hydrochemical model, three dominant instabilities of shape, Bjerknes, and diffusion are considered. The phase diagrams of the bubble in the (R0 - Pa) space are presented, and the parametric dependence of the light intensity is discussed. In contrast to water, the calculated thermal-bremsstrahlung mechanism of light emission at the fixed degassing condition of high SA concentrations shows that, with increasing the temperature of aqueous SA solutions, the light intensity increases. However, at diluted SA solutions similar to water, the light intensity decreases with increasing the ambient temperature. For 50 wt % SA, it was observed that the emitted light was almost temperature independent. Furthermore, it is found that, at the fixed temperatures of 20 C, 10 C, and 0 C, the aqueous solutions of 65 wt %, 50 wt %, and 45 wt % SA, respectively, have the maximum light emission.

Imani, Kh.; Bemani, F.; Silatani, M.; Sadighi-Bonabi, R.

2012-01-01

308

Ambient temperature effect on single-bubble sonoluminescence in different concentrations of sulfuric acid solutions.  

PubMed

The effect of ambient temperature on the parameters of the single-bubble sonoluminescence in sulfuric acid (SA) diluted in water is studied. Using a hydrochemical model, three dominant instabilities of shape, Bjerknes, and diffusion are considered. The phase diagrams of the bubble in the (R0 - Pa) space are presented, and the parametric dependence of the light intensity is discussed. In contrast to water, the calculated thermal-bremsstrahlung mechanism of light emission at the fixed degassing condition of high SA concentrations shows that, with increasing the temperature of aqueous SA solutions, the light intensity increases. However, at diluted SA solutions similar to water, the light intensity decreases with increasing the ambient temperature. For 50 wt % SA, it was observed that the emitted light was almost temperature independent. Furthermore, it is found that, at the fixed temperatures of 20?C, 10?C, and 0?C, the aqueous solutions of 65 wt %, 50 wt %, and 45 wt % SA, respectively, have the maximum light emission. PMID:22400679

Imani, Kh; Bemani, F; Silatani, M; Sadighi-Bonabi, R

2012-01-01

309

Dengue structure differs at the temperatures of its human and mosquito hosts  

PubMed Central

We report on a conformational transition of dengue virus when changing the temperature from that present in its mosquito vectors to that of its human host. Using cryoelectron microscopy, we show that although the virus has a smooth surface, a diameter of ?500 , and little exposed membrane at room temperature, the virions have a bumpy appearance with a diameter of ?550 and some exposed membrane at 37 C. The bumpy structure at 37 C was found to be similar to the previously predicted structure of an intermediate between the smooth mature and fusogenic forms. As humans have a body temperature of 37 C, the bumpy form of the virus would be the form present in humans. Thus, optimal dengue virus vaccines should induce antibodies that preferentially recognize epitopes exposed on the bumpy form of the virus.

Zhang, Xinzheng; Sheng, Ju; Plevka, Pavel; Kuhn, Richard J.; Diamond, Michael S.; Rossmann, Michael G.

2013-01-01

310

HA/Bioglass composite films deposited by pulsed laser with different substrate temperature  

NASA Astrophysics Data System (ADS)

In this experiment, the HA/Bioglass composite films on Ti-6Al-4V were deposited by a pulsed laser at Ar atmosphere, and the influence of substrate temperature on the morphology, phase constitutions, bonding configurations and adhesive strength of the films was studied. The obtained films were characterized by an electron probe microanalyzer (EPMA), scanning electron microscope (SEM), X-ray diffractometer (XRD), Fourier transform infrared spectrometer (FTIR), scratch apparatus, and so on. The results show that the amount of the droplets, the crystallinity, and the critical load of the deposited films all increase with the increase of the substrate temperature; however, the substrate temperature has little influence on the functional groups of the films.

Wang, D. G.; Chen, C. Z.; Jin, Q. P.; Li, H. C.; Pan, Y. K.

2014-03-01

311

Regulated and nonregulated diesel and gasoline cold start emissions at different temperatures  

NASA Astrophysics Data System (ADS)

The emissions of modern cars are usually reduced in warm engine conditions by catalysts. Consequently emissions are significantly higher during the cold start, i.e. the warm-up phase of the car. The duration of this period and the emissions produced during it depend on the ambient temperature as well as on the initial temperature of the car's systems. The cold start emissions of Euro-3 gasoline cars, Euro-2 diesel cars and old pre-Euro-1 gasoline cars were investigated at cold ambient temperatures. Since the goal was to get real-world emissions, the measurements were done with cars belonging to private owners taken straight from the road with no maintenance. The chassis dynamometer tests were carried out at +23, -7 and -20 C. The test cycle employed is a representative urban ride from a real-world driving behaviour study. Besides the regulated pollutants, methane, benzene and toluene were also measured online by chemical ionisation mass spectrometry.

Weilenmann, Martin; Soltic, Patrik; Saxer, Christian; Forss, Anna-Maria; Heeb, Norbert

312

Dengue structure differs at the temperatures of its human and mosquito hosts.  

PubMed

We report on a conformational transition of dengue virus when changing the temperature from that present in its mosquito vectors to that of its human host. Using cryoelectron microscopy, we show that although the virus has a smooth surface, a diameter of ?500 , and little exposed membrane at room temperature, the virions have a bumpy appearance with a diameter of ?550 and some exposed membrane at 37 C. The bumpy structure at 37 C was found to be similar to the previously predicted structure of an intermediate between the smooth mature and fusogenic forms. As humans have a body temperature of 37 C, the bumpy form of the virus would be the form present in humans. Thus, optimal dengue virus vaccines should induce antibodies that preferentially recognize epitopes exposed on the bumpy form of the virus. PMID:23569243

Zhang, Xinzheng; Sheng, Ju; Plevka, Pavel; Kuhn, Richard J; Diamond, Michael S; Rossmann, Michael G

2013-04-23

313

Detonation initiation of JP-8-oxygen mixtures at different initial temperatures  

NASA Astrophysics Data System (ADS)

Liquid fuel with sufficient vapor proportion at micron scale is essentially required to increase specific energy density and reduce volume requirements for application of pulse detonation engine. For JP-8, the fully vaporized temperature ranges from 380 to 410 K. In this study, the fuel vapor with oxygen is not enough to induce the reaction and leads to failure of detonation initiation at the initial temperature of 373 K. Condensed fuel was also observed on the bottom of detonation tube. At 393 K, the detonation wave was successfully generated even though a portion of fuel was in a liquid state. The deflagration-to-detonation run-up distance and the pressure trace at fully vaporized conditions, in which the initial temperatures were at 413, 433, and 453 K, were similar to those of gaseous mixtures, such as propane-oxygen mixture.

Wen, C.-S.; Chung, K.-M.; Lai, W.-H.

2012-09-01

314

Modeling compressive flow behavior of a tungsten heavy alloy at different strain rates and temperatures  

NASA Astrophysics Data System (ADS)

Room temperature stress-strain behavior was obtained for a tungsten heavy alloy at 9000, 0.1 and 0.0001/s strain rates. In addition, at the strain rate of 0.1/s, stress-strain data were obtained at 423 K, 573 K and 732 K. Deformation behavior was modeled using standard and modified Johnson-Cook (JC) and Power-Law (PL) models. In the modified models, the temperature terms are replaced by other functions that are proposed in the literature for these models as well as by Arrhenius type exponential functions. The best representation of the data was obtained from modified models with the exponential temperature functions. The model constants were determined using slow rate stress-strain data and the high rate yield stress. This paper presents the modified JC and PL models and the corresponding model constants for the tungsten heavy alloy.

Weerasooriya, Tusit

1998-07-01

315

Modeling compressive flow behavior of a tungsten heavy alloy at different strain rates and temperatures  

SciTech Connect

Room temperature stress-strain behavior was obtained for a tungsten heavy alloy at 9000, 0.1 and 0.0001/s strain rates. In addition, at the strain rate of 0.1/s, stress-strain data were obtained at 423 deg. K, 573 deg. K and 732 deg. K. Deformation behavior was modeled using standard and modified Johnson-Cook (JC) and Power-Law (PL) models. In the modified models, the temperature terms are replaced by other functions that are proposed in the literature for these models as well as by Arrhenius type exponential functions. The best representation of the data was obtained from modified models with the exponential temperature functions. The model constants were determined using slow rate stress-strain data and the high rate yield stress. This paper presents the modified JC and PL models and the corresponding model constants for the tungsten heavy alloy.

Weerasooriya, Tusit [Material Division, Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005 (United States)

1998-07-10

316

Dislocation structures in zirconium and zircaloy-4 fatigued at different temperatures  

SciTech Connect

The development of characteristic dislocation structures in pure zirconium and zircaloy-4 fatigued under pull-push strain control as the testing temperature and the cycle strain range varied was examined using a thin-foil transmission electron microscopy (TEM) technique. The slip planes and the twinning planes were determined by a standard stereographic trace analysis technique. The first-order prismatic slip {l_brace}10{bar 1}0{r_brace}, is the primary deformation mode in zirconium and zircaloy-4 fatigued from room temperature (RT) to 873 K. The pyramidal slip {l_brace}{bar 1}2{ovr 11}{r_brace} is activated at 673 K and at high cyclic strain ranges, whereas the basal slip {l_brace}0001{r_brace} only appears in those specimens fatigued at 873 K. The {l_brace}10{bar 1}2{r_brace}, {l_brace}11{bar 2}1{r_brace}, and {l_brace}11{bar 2}2{r_brace} types of twins were detected in specimens fatigued at RT. Twinning becomes less frequent as the testing temperature increases. The schematic map of the cyclic deformation modes as a function of the plastic strain range and the test temperature is described. The dislocation configurations in fatigued pure zirconium specimens evolve from a planar arrangement to a cell structure as the test temperature and the strain range increase. For zircaloy-4, the fatigued dislocation structure is parallel dislocation bands at 873 K, respectively. Finally, the fatigued dislocation-structure evolution map with the cyclic strain range and the test temperature are qualitatively established for zirconium and zircaloy-4, respectively. The effect factors on the fatigue mechanism and the thermodynamic and dynamic criteria of the dislocation-pattern evolution are discussed.

Xiao, L.; Gu, H. [Xi`an Jiaotong Univ. (China). Research Inst. for Strength of Materials

1997-04-01

317

Uncovering Different Masking Factors on Wrist Skin Temperature Rhythm in Free-Living Subjects  

PubMed Central

Most circadian rhythms are controlled by a major pacemaker located in the hypothalamic suprachiasmatic nucleus. Some of these rhythms, called marker rhythms, serve to characterize the timing of the internal temporal order. However, these variables are susceptible to masking effects as the result of activity, body position, light exposure, environmental temperature and sleep. Recently, wrist skin temperature (WT) has been proposed as a new index for evaluating circadian system status. In light of previous evidence suggesting the important relationship between WT and core body temperature regulation, the aim of this work was to purify the WT pattern in order to obtain its endogenous rhythm with the application of multiple demasking procedures. To this end, 103 subjects (1824 years old) were recruited and their WT, activity, body position, light exposure, environmental temperature and sleep were recorded under free-living conditions for 1 week. WT demasking by categories or intercepts was applied to simulate a constant routine protocol (awakening, dim light, recumbent position, low activity and warm environmental temperature). Although the overall circadian pattern of WT was similar regardless of the masking effects, its amplitude was the rhythmic parameter most affected by environmental conditions. The acrophase and mesor were determined to be the most robust parameters for characterizing this rhythm. In addition, a circadian modulation of the masking effect was found for each masking variable. WT rhythm exhibits a strong endogenous component, despite the existence of multiple external influences. This was evidenced by simultaneously eliminating the influence of activity, body position, light exposure, environmental temperature and sleep. We therefore propose that it could be considered a valuable and minimally-invasive means of recording circadian physiology in ambulatory conditions.

Martinez-Nicolas, Antonio; Ortiz-Tudela, Elisabet; Rol, Maria Angeles; Madrid, Juan Antonio

2013-01-01

318

Modeling of cw-EPR spectra of propagating radicals in methacrylic polymerization at different temperatures.  

PubMed

The temperature dependence of the cw-EPR spectra corresponding to the propagating radical responsible for the polymerization of methacrylic monomers has been simulated by an integrated computational approach that determines the structural and magnetic parameters (via quantum mechanical calculations) and diffusive properties (via hydrodynamic based methods), which represent the overall input of the stochastic Liouville equation that yields the spectrum. The system has been modeled as a rotator with only one relaxation process, the rotation around the C alpha-C beta bond. The simulations clearly indicate that the change of the spectral shape with the temperature is essentially related to the internal flexibility of the radical end. PMID:18707082

Hermosilla, Laura; Sieiro, Carlos; Calle, Paloma; Zerbetto, Mirco; Polimeno, Antonino

2008-09-11

319

Experimental Validation of a Tennis Ball Finite-element Model for Different Temperatures (P22)  

Microsoft Academic Search

An explicit finite-element (FE) model of a pressurised tennis ball was produced in Ansys\\/LS-DYNA 10.0 and validated at room\\u000a temperature. This model was successfully updated to simulate temperatures of 283.15 and 313.15 K (10 and 40 C), by adjusting\\u000a the internal pressure and material properties of the balls rubber core. The validation experiment was undertaken using an\\u000a impact rig in

Tom Allen; Simon Goodwill; Steve Haake

320

Experimental Validation of a Tennis Ball Finite-element Model for Different Temperatures (P22)  

Microsoft Academic Search

An explicit finite-element (FE) model of a pressurised tennis ball was produced in Ansys\\/LS-DYNA 10.0 and validated at room\\u000a temperature. This model was successfully updated to simulate temperatures of 283.15 and 313.15 K (10 and 40 C), by adjusting\\u000a the internal pressure and material properties of the balls rubber core. The validation experiment was undertaken using an\\u000a impact rig in

Tom Allen; Simon Goodwill; Steve Haake

321

Influence of different temperatures on the tachinid parastite, Sturmiopsis inferens [Dip.  

Microsoft Academic Search

The influence of constant temperatures of 27, 29, 31 and 33C and alternating temperature of 31\\/33C (18\\/6 h) onSturmiopsis inferens\\u000a Townsend was studied during 12 successive generations. The larval and pupal periods for male parasites were 13.50.5 and 11.00.3\\u000a days respectively and for female 12.80.5 and 11.10.3 days respectively in the 1st generatioin at 27C. It decreased progressively\\u000a with increase

H. David; S. Easwaramoorthy; V. Nandagopal; N. K. Kurup; M. Shanmugasundaram; G. Santhalakshmi

1981-01-01

322

Comparison of temperature increase in in vitro human tooth pulp by different light sources in the dental whitening process.  

PubMed

This work evaluated the increase in dental pulp temperature caused by different light sources, used in the dental whitening process, following the irradiation protocol from the light manufacturer. Human incisor, canine and premolar teeth were used. A whitening gel made of hydrogen peroxide 35% v/v and a condenser agent were applied to each tooth, on the vestibular surface, and was activated by five different light sources: photo-polymerizer with blue bandpass filtered halogen lamp (HL) (600 mW, lambda = 430-480 nm), blue light emitting diode (LED) (BL) (1 W, lambda = 470 nm), blue LED associated with infrared diode laser (BL+IL) (120 mW, lambda = 795 nm), green LED (GL) (600 mW, lambda = 530 nm) and green LED associated with infrared diode laser (GL+IL) (120 mW, lambda = 795 nm), with the equipment turned on, an exposure time of 1 min, and resting time of 30 s, repeated three times. The temperature was measured at the beginning and ending of exposure by a digital thermometer (type K thermocouple), placed inside the dental pulp chamber. Analyzing the mean temperature variation that occurred along the irradiation time, we found that the BL and BL+IL group presented the highest temperature variations, mainly in the incisor tooth. The GL and GL+IL presented the lowest temperature increase. The maximum temperature variation reached was 5.5 degrees C for the BL+IL in the incisor tooth. The HL presented a smaller temperature variation than the BL did, but it had a residual temperature when the light was off. The GL and GL+IL promoted a non-significant temperature increase, as low as 1 degrees C, even with total power equal to the that of the HL. PMID:18274815

Coutinho, Daniela Soares; Silveira, Landulfo; Nicolau, Renata Amadei; Zanin, Ftima; Brugnera, Aldo

2009-03-01

323

Finite-element and finite-difference simulations of the mechanical behavior of austenitic steels at different strain rates and temperatures  

Microsoft Academic Search

Presented in this paper are the computational results on deformation of austenitic steels at different strain rates and temperatures. To describe the dynamic response of steels a relaxation constitutive equation was developed using a thermomechanical physically-based model. On the base of experimental data on uniaxial loading of new steels in the range of strain rates from 0.001 to 500s?1 the

R. R. Balokhonov; V. A. Romanova; S. Schmauder

2009-01-01

324

The relationship between heart rate and rate of oxygen consumption in Galapagos marine iguanas (Amblyrhynchus cristatus) at two different temperatures.  

PubMed

To enable the use of heart rate (fH) for estimating field metabolic rate (FMR) in free-ranging Galapagos marine iguanas Amblyrhynchus cristatus, we determined the relationships between fH and mass-specific rate of oxygen consumption (sVO2) in seven iguanas before and during exercise on a treadmill and during the post-exercise period. The experiments were conducted at 27 and 35 degrees C, which are the temperatures that represent the lowest and highest average body temperatures of these animals in the field during summer. There were linear and significant relationships between fH and sVO2 at both temperatures (r(2)=0.86 and 0.91 at 27 degrees C and 36 degrees C, respectively). The slopes of the two regression lines did not differ, but there were significant differences in their intercepts. Thus, while heart rate can be used to predict FMR, the effects of temperature on the intercept of the regression must be taken into account when converting fH to sVO2. On the basis of our data, this can be achieved by applying the following formula: sVO2=0.0113fH-0.2983Q(10)((T(b)-27)/10). The increase in sVO2 with elevated body temperature results from an increase in fH, with no significant change in mass-specific oxygen pulse (sO(2) pulse; cardiac stroke volume times the difference in oxygen content between arterial and mixed venous blood). However, during exercise at both temperatures, increases in fH are insufficient to provide all of the additional O(2) required and there are also significant increases in the sO(2) pulses. This creates the situation whereby the same fH at the two temperatures can represent different values of sVO2. PMID:12077168

Butler, Patrick J; Frappell, Peter B; Wang, Tobias; Wikelski, Martin

2002-07-01

325

Calculational and Experimental Study of Temperature Effect in Uranium-Water Systems with Different Absorbers.  

National Technical Information Service (NTIS)

Effects of burnable poison types and the way of their arrangement in the core on the formation and value of the temperature reactivity coefficient for the quasihomogeneous water-uranium ABW-1.5 type reactor core has been investigated. Results of calculati...

V. I. Lependin V. I. Matveenko V. I. Bagretsov

1980-01-01

326

Comparison of annual energy performances with different ventilation methods for temperature and humidity control  

Microsoft Academic Search

Stratum ventilation has been proposed to accommodate elevated indoor temperatures recommended by governments in East Asia. TRNSYS is used for computation of the space cooling loads, sensible and latent, as well as system energy consumption. Typical configurations of an office, a classroom and a retail shop in Hong Kong are investigated. Desiccant dehumidification with and without solar assistance is utilized

Zhang Lin; C. K. Lee; K. F. Fong; T. T. Chow

2011-01-01

327

Transport of silver catfish ( Rhamdia quelen) fingerlings at different times, load densities, and temperatures  

Microsoft Academic Search

Silver catfish (Rhamdia quelen) fingerlings (510 cm) were caught from a fish culture pond and placed in a tank for stomach emptying for 24 h. Fingerlings were then weighed and placed in plastic bags (5 l) with 1.5 l water and oxygen, which were kept at temperatures of 15, 20, and 25 C. The load densities tested were 50, 67,

J. I Golombieski; L. V. F Silva; B Baldisserotto; J. H. S da Silva

2003-01-01

328

SPATIAL DISTRIBUTION OF THE AIR TEMPERATURE IN THE AMERICAN ARCTIC FOR DIFFERENT DATABASES AND METHODS  

Microsoft Academic Search

Meteorological observations (mainly air temperature, pressure and wind direction) made in the 19th century in the Canadian Arctic on vessels sent there by the Royal Navy are very valuable in the study of the Artic climate. They were gathered during winterings sometimes far from any present meteorological site. To analyse the climate change we should know the present-day climate conditions

Vizi Zsuzsanna; Przybylak Rajmund

329

Responses to bleaching herbicides by leaf chloroplasts of maize plants grown at different temperatures.  

PubMed

The effects of growth temperature on chloroplast responses to norflurazon and amitrole, two herbicides inhibiting carotenogenesis, at phytoene desaturation and lycopene cyclization, respectively, were studied in leaves of maize plants grown at 20 degrees C and 30 degrees C in light. At the lower temperature both chemicals caused severe photo-oxidative damage to chloroplasts. In organelles of norflurazon-treated leaves neither carotenoids nor chlorophylls were detectable and the thylakoid system was dismantled. In organelles of amitrole-treated leaves lycopene was accumulated, but small quantities of beta-carotene and xanthophylls were also produced. Moreover, some chlorophyll and a few inner membranes still persisted, although these latter were disarranged, lacking essential protein components and devoid of photosynthetic function. The increase in plant growth temperature to 30 degrees C did not change the norflurazon effects on carotenoid synthesis and the photo-oxidative damage suffered by chloroplasts. By contrast, in organelles of amitrole-treated leaves a large increase in photoprotective carotenoid biosynthesis occurred, with a consequent recovery of chlorophyll content, ultrastructural organization and thylakoid composition and functionality. This suggests that thermo-modulated steps could exist in the carotenogenic pathway, between the points inhibited by the two herbicides. Moreover it shows that, unlike C(3) species, C(4) species, such as maize, can express a strong tolerance to herbicides like amitrole, when supplied to plants growing at their optimum temperature conditions. PMID:11413217

Vecchia, F D; Barbato, R; La Rocca, N; Moro, I; Rascio, N

2001-04-01

330

Production of biomass and nutraceutical compounds by Spirulina platensis under different temperature and nitrogen regimes  

Microsoft Academic Search

The cyanobacterium Spirulina platensis has been used by humans because of its nutritional and possibly medicinal effects. Our study evaluated the influence of temperature and nitrogen concentration in the medium on the production of biomass by this cyanobacterium and the biomass composition in protein, lipid and phenolic compounds. We found that at 35C there was a negative effect on biomass

Luciane Maria Colla; Christian Oliveira Reinehr; Carolina Reichert; Jorge Alberto Vieira Costa

2007-01-01

331

Field emission properties of diamond-like carbon films annealed at different temperatures  

Microsoft Academic Search

Effect of annealing on the field emission properties of diamond-like carbon (DLC) films deposited by high power excime laser technique was studied. Raman spectrometry and X-ray photoelectron spectrometry (XPS) were used to determine the chemical bonding structural change of the annealed DLC films. It was found that the annealing transformed gradually DLC films into a graphitic structure as annealing temperature

J. J. Li; C. Z. Gu; H. Y. Peng; H. H. Wu; W. T. Zheng; Z. S. Jin

2005-01-01

332

Comparison of diesel spray combustion in different high-temperature, high-pressure facilities.  

SciTech Connect

Diesel spray experiments at controlled high-temperature and high-pressure conditions offer the potential for an improved understanding of diesel combustion, and for the development of more accurate CFD models that will ultimately be used to improve engine design. Several spray chamber facilities capable of high-temperature, high-pressure conditions typical of engine combustion have been developed, but uncertainties about their operation exist because of the uniqueness of each facility. For the IMEM meeting, we describe results from comparative studies using constant-volume vessels at Sandia National Laboratories and IFP. Targeting the same ambient gas conditions (900 K, 60 bar, 22.8 kg/m{sup 3}, 15% oxygen) and sharing the same injector (common rail, 1500 bar, KS1.5/86 nozzle, 0.090 mm orifice diameter, n-dodecane, 363 K), we describe detailed measurements of the temperature and pressure boundary conditions at each facility, followed by observations of spray penetration, ignition, and combustion using high-speed imaging. Performing experiments at the same high-temperature, high-pressure operating conditions is an objective of the Engine Combustion Network (http://www.ca.sandia.gov/ECN/), which seeks to leverage the research capabilities and advanced diagnostics of all participants in the ECN. We expect that this effort will generate a high-quality dataset to be used for advanced computational model development at engine conditions.

Christiansen, Caspar (Technical University of Denmark); Hermant, Laurent (IFP); Malbec, Louis-Marie (IFP); Bruneaux, Gilles (IFP); Genzale, Caroline L.; Pickett, Lyle M.; Schramm, Jesper (Technical University of Denmark)

2010-05-01

333

Temperature  

NASA Technical Reports Server (NTRS)

The problems in human comfort in heat stress are emphasized, with less emphasis placed upon cold exposure problems. Physiological parameters related to human thermal interactions are discussed, as well as data concerning thermal protective clothing. The energy balance equation, heat transfer equation, thermal comfort, heat stress, and cold stress are also considered. A two node model of human temperature regulation in FORTRAN is appended.

Berenson, P. J.; Robertson, W. G.

1973-01-01

334

Compressive behavior of bulk metallic glass under different conditions --- Coupled effect of temperature and strain rate  

NASA Astrophysics Data System (ADS)

Metallic glass was first reported in 1960 by rapid quenching of Au-Si alloys. But, due to the size limitation, this material did not attract remarkable interest until the development of bulk metallic glasses (BMGs) with specimen sizes in excess of 1 mm. BMGs are considered to be promising engineering materials because of their ultrahigh strength, high elastic limit and wear resistance. However, they usually suer from a strong tendency for localized plastic deformation with catastrophic failure. Many basic questions, such as the origin of shear softening and the strain rate eect remain unclear. In this thesis, the mechanical behavior of the Zr55Al 10Ni5Cu30 bulk metallic glass and a metallic glass composite is investigated. The stress-strain relationship for Zr55Al10Ni 5Cu30 over a wide range of strain rate (5x10 --5 to 2x103 s--1) was investigated in uniaxial compression loading using both MTS servo-hydraulic system (quasi-static) and compression Kolsky bar system (dynamic). The effect of the strain rate on the fracture stress at room temperature was discussed. Based on the experimental results, the strain rate sensitivity of the bulk metallic glass changes from a positive value to a negative value at high strain rate, which is a consequence of the significant adiabatic temperature rise during the dynamic testing. In order to characterize the temperature eect on the mechanical behavior of the metallic glass, a synchronically assembled heating unit was designed to be attached onto the Kolsky bar system to perform high temperature and high strain rate mechanical testing. A transition from inhomogeneous deformation to homogeneous deformation has been observed during the quasi-static compressive experiments at testing temperatures close to the glass transition temperature. However, no transition has been observed at high strain rates at all the testing temperatures. A free volume based model is applied to analyze the stress-strain behavior of the homogeneous deformation. To further examine the inelastic deformation of the Zr-based bulk metallic glasses, instrumented nanoindentation experiments were performed. A transition from discrete plastic deformation to continuous plastic deformation was found when strain rate is increased but still within the quasi-static strain rate region. Motivated by the metal matrix composite material, a tungsten reinforced BMG composite was investigated at quasi-static and dynamic strain rates. The mechanical behavior of the metallic glass matrix was improved significantly by the addition of W particles.

Yin, Weihua

335

Studies on the effect of plasticiser and addition of toluene diisocyanate at different temperatures in composite propellant formulations.  

PubMed

Different composite propellant mixtures have been prepared using ammonium perchlorate, aluminium powder and hydroxyl terminated polybutadiene by varying the percentage of plasticiser and addition of toluene diisocyanate at different temperatures, and studied their different properties such as viscosity build-up, mechanical and ballistic properties and sensitivity. The data on different plasticiser level indicate that on decreasing the plasticiser content, there is a significant enhancement in end of mix viscosity, tensile strength and modulus while elongation decreases drastically. The data on sensitivity of the studied mixtures reveal that on decreasing the percentage of plasticiser, the sensitivity increases, accordingly. Further, the data on the effect of addition of TDI at different temperatures (35-60 degrees C) infer that on increasing the addition temperature of TDI there is a decrease in end of mix viscosity i.e. 800Pas at 35 degrees C to 448Pas at 60 degrees C. Moreover, there is no effect on mechanical and ballistic properties on higher temperature addition of TDI was observed. PMID:18835097

Jawalkar, S N; Mehilal; Ramesh, K; Radhakrishnan, K K; Bhattacharya, B

2009-05-30

336

Different nocturnal body temperatures and sleep with forced-air warming in men and in women taking hormonal contraceptives.  

PubMed

We studied how forced-air warming, conventionally used to control body temperature during and after anaesthesia, affected the nocturnal rectal temperatures and sleep composition of young men and women. Seven healthy women who were taking oral or injection contraceptives, and six healthy men spent 3 nights in a controlled environment: an adaptation night followed by 2 nights when they slept under either a down duvet (baseline) or a quilt perfused with warm air (hot). Repeated analysis of variance (ANOVA) revealed significant gender differences in the body temperature responses. On the baseline night, despite sleeping under the same conditions, the women did not show a nocturnal drop in body temperature as shown by the men. Forced-air warming increased body temperature to a similar extent in the men and the women, and resulted in enhanced hyperthermia in the women, and blunted the drop in body temperature in the men, compared to their baseline nights. The significant increases in body temperature had no consequences, however, for the subjective sleep quality of either the men or women, and only minor consequences for objective sleep composition. Both men and women had increased amounts of Stage 2 sleep on the hot night (P < 0.04). In addition, the women had reduced rapid eye movement (REM) sleep when compared to their baseline night (P < 0.04). Our results confirm that in a passive thermal environment, women who are taking oral or injection contraceptives have higher nocturnal body temperatures than men. Also, as sleep architecture was minimally affected by the increases in body temperature of between 0.2 and 0.3 degree C on the hot night in the men and women, and subjective sleep quality was unaffected, our results question the existence of a tight association between sleep and body temperature. PMID:9785272

Baker, F C; Selsick, H; Driver, H S; Taylor, S R; Mitchell, D

1998-09-01

337

Proposal of quantitative temperature measurements using two-color technique combined with several infrared radiometers having different detection wavelength bands  

NASA Astrophysics Data System (ADS)

Infrared thermography has been widely used to visualize a 2D temperature field for various engineering applications. However, in general, conventional infrared thermography cannot directly be applied to quantitative temperature measurement on glossy metal surfaces under near-ambient conditions, because of the severe influence of the reflected energy incident from the surroundings on the measurement. When it is necessary to measure the temperature quantitatively, an appropriate calibration involving complicated procedures must be performed. In this paper, therefore, a new technique of measuring temperature is proposed for near-ambient conditions, by combining simultaneously several infrared radiometers having different detection wavelength bands to enable a two-color technique, which does not require any temperature calibrations. The sensors concerned have a selective wavelength band of several micrometers in width in the range of 2 to 13 micrometers . The applicability of the method, including a series of proposed equations, has been confirmed by an investigation; the numerical simulation presented merely allows a parametric study of how the result varies for different values of emissivity corresponding to a pair of infrared radiometers. An experimental investigation is also performed to estimate or correct the measurement error pertaining to the present technique. This technique has the feature that a 2D temperature field can be evaluated quantitatively, nondestructively, and simultaneously at each picture element without presuming any emissivity and reflectivity, even though the object has a complicated shape; so that it may be useful in various medical or engineering applications.

Inagaki, Terumi; Ishii, Toshimitsu

2001-03-01

338

Effect of temperature difference between manikin and wet fabric skin surfaces on clothing evaporative resistance: how much error is there?  

NASA Astrophysics Data System (ADS)

Clothing evaporative resistance is one of the inherent factors that impede heat exchange by sweating evaporation. It is widely used as a basic input in physiological heat strain models. Previous studies showed a large variability in clothing evaporative resistance both at intra-laboratory and inter-laboratory testing. The errors in evaporative resistance may cause severe problems in the determination of heat stress level of the wearers. In this paper, the effect of temperature difference between the manikin nude surface and wet textile skin surface on clothing evaporative resistance was investigated by both theoretical analysis and thermal manikin measurements. It was found that the temperature difference between the skin surface and the manikin nude surface could lead to an error of up to 35.9% in evaporative resistance of the boundary air layer. Similarly, this temperature difference could also introduce an error of up to 23.7% in the real clothing total evaporative resistance ( R et_real < 0.1287 kPa m2/W). Finally, it is evident that one major error in the calculation of evaporative resistance comes from the use of the manikin surface temperature instead of the wet textile fabric skin temperature.

Wang, Faming; Kuklane, Kalev; Gao, Chuansi; Holmr, Ingvar

2012-01-01

339

Temperature sensitivity of extracellular enzyme kinetics in subtropical wetland soils under different nutrient and water level conditions  

NASA Astrophysics Data System (ADS)

Microbial extracellular enzymes play an important role in the initial steps of soil organic matter decomposition and are involved in regulating nutrient cycle processes. Moreover, with the recent concern of climate change, microbial extracellular enzymes may affect the functioning (C losses, C sequestration, greenhouse gas emissions, vegetation changes) of different ecosystems. Hence, it is imperative to understand the biogeochemical processes that may be climate change sensitive. Here, we have measured the Michaelis Menten Kinetics [maximal rate of velocity (Vmax) and half-saturation constant (Km)] of 6 enzymes involved in soil organic matter decomposition (phosphatase, phosphodiesterase, ?-D-glucosidase, cellobiohydrolase, leucine aminopeptidase, N-Acetyl-?-D glucosaminidase) in different nutrient(P) concentration both aerobically and anaerobically in Everglade water conservation area 2A (F1, F4-slough and U3-slough). Temperature sensitivity of different enzymes is assessed within soil of different P concentrations. We hypothesized that the temperature sensitivity of the enzyme changes with the biogeochemical conditions including water level and nutrient condition. Furthermore, we have tested specific hypothesis that higher P concentration will initiate more C demand for microbes leading to higher Vmax value for carbon processing enzymes in high P site. We found temperature sensitivity of all enzymes for Vmax and Km under both aerobic and anaerobic condition ranges from 0.6 to 3.2 for Vmax and 0.5 to 2.5 for Km. Q10 values of Km for glucosidase indicate more temperature sensitivity under anaerobic condition. Under aerobic condition higher temperature showed significant effect on Vmax for bisphosphatase between high P and low P site. Decreasing P concentration from F1 site to U3-S site had showed significant effect in all temperature on carbon processing enzyme. This suggests that in high P site, microbes will use more carbon-processing enzyme to get more carbon due to easily available P. N-Acetyl-?-D glucosaminidase, cellobiohydrolase, phosphatase showed significant site effect in 25C and 30C. Anaerobic condition also showed significant site effect on carbon processing enzyme's temperature sensitivity for Vmax. No enzyme showed significant interaction between sites and temperatures for Km. Only phosphatase showed significant interaction between site and temperature sensitivity for Km. Our results showed higher Q10 values for Vmax over Km; indicating more decomposition at higher temperature. In summary, the results suggest that increasing concentration of P will increase carbon processing enzyme activity that leads to higher decomposition rate.

Goswami, S.; Inglett, K.; Inglett, P.

2012-12-01

340

Environmental impact of submerged anaerobic MBR (SAnMBR) technology used to treat urban wastewater at different temperatures.  

PubMed

The objective of this study was to assess the environmental impact of a submerged anaerobic MBR (SAnMBR) system in the treatment of urban wastewater at different temperatures: ambient temperature (20 and 33C), and a controlled temperature (33C). To this end, an overall energy balance (OEB) and life cycle assessment (LCA), both based on real process data, were carried out. Four factors were considered in this study: (1) energy consumption during wastewater treatment; (2) energy recovered from biogas capture; (3) potential recovery of nutrients from the final effluent; and (4) sludge disposal. The OEB and LCA showed SAnMBR to be a promising technology for treating urban wastewater at ambient temperature (OEB=0.19 kW h m(-3)). LCA results reinforce the importance of maximising the recovery of nutrients (environmental impact in eutrophication can be reduced up to 45%) and dissolved methane (positive environmental impact can be obtained) from SAnMBR effluent. PMID:24119499

Pretel, R; Robles, A; Ruano, M V; Seco, A; Ferrer, J

2013-12-01

341

Room-temperature gas sensing studies of polyaniline thin films deposited on different substrates  

NASA Astrophysics Data System (ADS)

Polyaniline thin films, doped with an inorganic acid (HCl), on glass and Si substrates were directly synthesized by an in situ polymerization technique. Studies on the surface morphology as well as topography proved that the film surface is evolved differently on different substrates. The formation of PANI on glass and Si substrates was confirmed by optical and infrared spectroscopy, respectively. Different surface characteristics for different substrates showed a strong effect on the gas sensing properties of these films. The porous fibril morphology on the Si substrate leads to significantly faster and more responsive sensing phenomena.

Deshpande, N. G.; Gudage, Y. G.; Devan, R. S.; Ma, Y. R.; Lee, Y. P.; Sharma, Ramphal

2009-09-01

342

Application of finite elementfinite difference method to the determination of transient temperature field in functionally graded materials  

Microsoft Academic Search

A finite element\\/finite difference method (FEM\\/FDM) is developed to solve the time-dependent temperature field in non-homogeneous materials such as functionally graded materials. The method uses the finite element space discretization to obtain a first-order system of differential equations, which is solved by employing finite difference scheme to resolve the time-dependent response. A computation code is developed in the programming environment

Bao-Lin Wang; Zhen-Hui Tian

2005-01-01

343

Forming limit of textured AZ31B magnesium alloy sheet at different temperatures  

Microsoft Academic Search

Repeated unidirectional bending (RUB) was carried out to improve the texture of commercial AZ31B magnesium alloy sheets. All specimens were prepared in the rolling direction. The forming limit diagrams (FLDs) of AZ31B magnesium alloy sheet were determined experimentally by conducting stretch-forming tests at room temperature, 100, 200 and 300 C. Compared with the as-received sheet, the lowest limited strain of

Guang-sheng HUANG; Hua ZHANG; Xiao-yun GAO; Bo SONG; Lei ZHANG

2011-01-01

344

Comparison of temperature and work function measurements obtained with different GTA electrodes  

Microsoft Academic Search

This work was carried out on one standard electrode (W-ThO2,) and other electrodes developed by additions of La2O3, CeO2, and Y2O3,. The effect of rare-earth metal oxides on GTAW electrode phenomena, concerning electrode temperature, emissivity, and work function, was analyzed and compared from the point of view of those oxides' behavior during arcing. The experimental results indicate that the electrode

Masao Ushio; Alber A. Sadek; Fukuhisa Matsuda

1991-01-01

345

Terahertz absorption spectrum of para and ortho water vapors at different humidities at room temperature  

Microsoft Academic Search

Terahertz time-domain spectroscopy has been used to measure the absorption of water vapor in 0.2-2.4 THz range from low to high humidity at room temperature. The observed absorption lines are due to the water molecular rotations in the ground vibrational state. We find that the absorption strength of para transitions increases as humidity increases, while the absorption strength of ortho

X. Xin; H. Altan; A. Saint; D. Matten; R. R. Alfano

2006-01-01

346

Tribology of ultra-high molecular weight polyethylene disks molded at different temperatures  

Microsoft Academic Search

Tribological characteristics of ultra-high molecular weight polyethylene (UHMW-PE) disks molded at 130190C were studied. The highest crystallinity was obtained for the sheet molded at 130C, but crystallinity decreased with increasing molding temperature. Beyond 150C, the resultant crystallinity reached a constant level. The dynamic friction coefficients of these UHMW-PE disks were measured using a ball-on-disk friction tester. The friction coefficient decreased

Taku Aoike; Daisuke Yokoyama; Hiroki Uehara; Takeshi Yamanobe; Tadashi Komoto

2007-01-01

347

Soil depth detection by seeds and diurnally fluctuating temperatures: different dynamics in 10 annual plants  

Microsoft Academic Search

Background and AimsSeeds buried in the soil detect burial depth through light and diurnally fluctuating temperatures (DFT) and in this way limit\\u000a losses due to germination too deep in the soil. DFTs and germination also increase in vegetation gaps. However, dry open environments\\u000a with high DFTs can also increase seedling mortality, creating conflicting selection pressures for reaction to DFTs. Since

Arne Saatkamp; Laurence Affre; Teddy Baumberger; Pierre-Jean Dumas; Ada Gasmi; Sophie Gachet; Fabien Arne

348

Chemical study of extracted rockrose and of chars and activated carbons prepared at different temperatures  

Microsoft Academic Search

This paper discusses the chemical composition and chemical structure of rockrose (Cistus ladaniferus L.) extracted into petroleum ether and resulting chars as well as activated carbons. The isothermal temperature of carbonization of extracted rockrose (Jex) in N2 ranged between 600 and 1000C. The char (CJex-600) employed in the preparation of activated carbons was prepared by treatment of Jex at 30600C.

J Pastor-Villegas; V Gmez-Serrano; C. J Durn-Valle; F. J Higes-Rolando

1999-01-01

349

Flow and fracture behaviour of FV535 steel at different triaxialities, strain rates and temperatures  

Microsoft Academic Search

The new generation jet engines operate at highly demanding working conditions. Such conditions need very precise design which implies an exhaustive study of the engine materials and behaviour in their extreme working conditions. With this purpose, this work intends to describe a numerically-based calibration of the widely-used JohnsonCook fracture model, as well as its validation through high temperature ballistic impact

B. Erice; F. Glvez; D. A. Cendn; V. Snchez-Glvez

350

Electrophoretic Properties of Casein from Sterilized Milk Stored at Different Temperatures1  

Microsoft Academic Search

R. M~'L. WHITNEY Departme~t of Food TveI~ology, Uniformity of lllh~ois, ~rba~a SUMMARY High-temperature short-time steriliz~tion of nlilk did not hydrolyze the proteins but it denatured some serum proteins which were precipitated with the casein, and either moved at the same mobility at pH 8.7 as u-casein, or was associated with it and increased the area under the peak. A split

Lalitha Murthy; E. O. Herreid; R. Mc L. Whitney

1958-01-01

351

Continuous microwave saturation of EPR spectra of melanin complexes at different temperatures  

NASA Astrophysics Data System (ADS)

Paramagnetic centers in DOPA-melanin and complexes of DOPA-melanin with netilmicin and Cu(II) were studied by the use of an X-band (9.3 GHz) electron paramagnetic resonance (EPR) spectroscopy. Measurements of continuous microwave saturation of EPR spectra at temperatures: 125 K, 175 K, 225 K, 275 K, were performed. Homogeneous broadening of all the examined EPR spectra was observed. EPR spectra of DOPA-melanin-Cu(II) complexes saturated at higher microwave powers than the others tested melanin samples. Fast spin-lattice relaxation exists in DOPA-melanin-Cu(II) complexes. Slow spin-lattice relaxation processes exist in melanin's paramagnetic centers of DOPA-melanin and its complexes with netilmicin, and its complexes with both netilimicin and Cu(II). EPR spectra of all the tested samples saturated at higher microwave powers with increasing of the measuring temperature. Faster spin-lattice relaxation processes occurs in DOPA-melanin and its complexes with netilmicin and Cu(II) at higher temperature.

Zdybel, Magdalena; Pilawa, Barbara; Buszman, Ewa; Wrzesniok, Dorota; Krzyminiewski, Ryszard; Kruczynski, Zdzislaw

2011-01-01

352

Energy conversion derived from pressure and temperature differentials at different elevations  

SciTech Connect

A method and system of energy conversion derived from temperature and pressure differentials that may be provided between high and low elevations is disclosed. A solution of a liquid in a gas is transported in a first conduit from a low elevation to a high elevation, whereby the absolute pressure and the temperature of the solution change. Some of the liquid separates out of the solution in the first conduit in the form of particles suspended in the remaining solution to create a mixture of the separated particles and the remaining solution in the first conduit as a result of the changes in absolute pressure and temperature, so that at any particular position in the first conduit where the separation takes place, the average proportional density of the mixture after the separation has taken place is decreased in relation to the density of the solution at such position prior to the separation taking place. The mixture is transported into a separation chamber at the high elevation in response to pressure differentials created by the decrease in average proportional density of the mixture in the first conduit. At least of portion of the suspended particles are separated from the mixture in the separation chamber to create a separated liquid, and a dried gas; and the separated liquid is transported through a second conduit to a transducer at a lower elevation than the high elevation. The transducer converts the pressure and motion of the transported separated liquid into a useful form of energy.

Kira, G.S.; Sorensen, J.O.

1983-05-10

353

Temperature Increase during Different Post Space Preparation Systems: An In Vitro Study  

PubMed Central

INTRODUCTION: The purpose of this study was to evaluate external root surface temperature rise during post space preparation using LA Axxess bur, Beefill pack System, and Peeso Reamer drill. MATERIALS AND METHODS: The distal canals of forty-five extracted human permanent mandibular first molars were instrumented in crown-apical manner and obturated with lateral condensation technique. Teeth were then randomly divided into three groups according to post space preparation technique including: group 1. LA Axxess bur (Sybronendo Co., CA, USA), group 2 Beefill pack System (VD W Co., Munich, Germany) and group 3 Peeso Reamer drill (Mani Co., Tochigi-ken, Japan). Temperature was measured by means of digital thermometer MT-405 (Comercio Co., Sao Paulo, Brazil) which was installed on the root surfaces. Data was collected and submitted to one-way ANOVA and Post hoc analysis. RESULTS: Root surface temperatures were found to be significantly higher (7.32.7 vs. 4.32.1 and 42.4,) in samples of Beefill pack System compared with the two other groups (P<0.02). CONCLUSION: Using Beefill pack System during post space preparation may be potentially hazardous for periodontal tissues.

Nazari Moghadam, Kiumars; Shahab, Shahriar; Shirvani, Soghra; Kazemi, Ali

2011-01-01

354

Differential stability of TATA box binding proteins from archaea with different optimal growth temperatures  

NASA Astrophysics Data System (ADS)

The TATA box binding protein (TBP) is involved in promoter recognition, the first step of transcription initiation. TBP is universally conserved and essential in archaea and eukaryotes. In archaea, TBPs have to be stable and to function in species that cover an extremely wide range of optimal growth temperatures (OGTs), from below 0 C to more than 100 C. Thus, the archaeal TBP family is ideally suited to study the evolutionary adaptation of proteins to an extremely wide range of temperatures. We characterized the thermostability of one mesophilic and one thermophilic TBP by infrared spectroscopy. Transition temperatures ( Tms) of thermal unfolding have been determined using TBPs from Methanosarcina mazei (OGT 37 C) and from Methanothermobacter thermautotrophicus (OGT 65 C). Furthermore, the influence of protein and salt concentration on thermostability has been characterized. Together with previous studies, our results reveal that the Tms of archaeal TBPs are closely correlated with the OGTs of the respective species. Noteworthy, this is also true for the TBP from M. mazei representing the first characterized TBP from a mesophilic archaeon. In contrast, the only characterized eukaryotic TBP of the mesophilic plant Arabidopsis thaliana has a Tm more than 40 C above the OGT.

Kopitz, Annette; Soppa, Jrg; Krejtschi, Carsten; Hauser, Karin

2009-09-01

355

The assessment of different operating strategies for minimising activated sludge deflocculation under temperature transient conditions.  

PubMed

Three operating strategies were tested for decreasing activated sludge deflocculation due to temperature shifts from 30 degrees to 45 degrees C: magnesium sludge enrichment, increased sludge retention time (33 d), and spikes of an easily degradable substrate (methanol). The temperature shifts were conducted sequentially in 4 parallel lab-scale sequencing batch reactors (SBRs) treating kraft pulp mill effluent. Three SBRs operated at an SRT = 20 days, and in one of them the sludge was not manipulated, thus, serving as a reference SBR. The temperature shift was associated with decreased soluble chemical oxygen demand (SCOD) removals, decreased sludge settleability and substrate removal capacity, and increased effluent suspended solids (ESS) and turbidity levels. The shift also increased the sludge specific respiration rates and reduced the sludge substrate removal capacity. Sludge deflocculation was assessed as floc solubilisation (increased effluent SCOD levels) and floc fragmentation (increase in effluent solids smaller than 50 microm). Mg enrichment of the sludge and methanol spikes reduced the ESS levels (in 9 and 25%), and the three operating strategies decreased effluent turbidity (in 22-35%) compared to the maximum levels from the non-manipulated reactor (44 mg ESS/L). The stronger sludge floc structure achieved by magnesium enrichment and a high sludge age of 33 days was unsuccessful in significantly decreasing deflocculation. The mechanisms involved in sludge deflocculation require further fundamental research. PMID:15461400

Morgan-Sagastume, F; Allen, D Grant

2004-01-01

356

Measurements of Sr/Ca in bones to evaluate differences in temperature  

NASA Astrophysics Data System (ADS)

Analysis of aragonite from sea shells and coral skeletons showed a clear correlation between the strontium and calcium concentrations for these crystals (Sr/Ca ratio) and seawater temperature obtained by satellites and ship readings. In this work we present the results of a study that correlates Sr/Ca ratio with formation temperature of another calcium crystal, the hydroxyapatite (Ca 10(PO 4) 6(OH) 2), main mineral compound of teeth and bones from vertebrates. These animals, independent of its thermoregulation pattern (endothermic or ectothermic) have variations of internal temperature along the body. One interesting application of this work is to differentiate warm-blooded animals from cold-blooded ones just by measuring Sr/Ca ratio in their bones. Bones from a crocodile from Caiman yacare species and two dogs, a poodle and a non defined race, were analyzed using PIXE technique and thick target correction. A 1.78 (18) MeV external proton beam was used in LAMFI-USP with an accumulated charge of about 10 ?C for probing the samples. Emitted X-rays were collected using Si-PIN detectors (140 keV for Fe). As in coral skeletons, the Sr/Ca ratio of animals is lower in the body's warmer parts and higher in colder parts.

Santos, P. R.; Added, N.; Aburaya, J. H.; Rizzutto, M. A.

2008-04-01

357

Growth, Composition, and Fin Quality of Atlantic Salmon Fed Different Diets at Seasonal Temperatures in a Laboratory and Hatchery.  

National Technical Information Service (NTIS)

In the present 2-year, two-part study, we compared growth and general quality of Atlantic salmon fed different diets and held at seasonal temperatures of 1-18 deg C. The fish were fed six diets in the laboratory at the National Fishery Research and Develo...

B. A. Dennison C. A. Lemm D. S. Dropkin D. V. Rottiers

1988-01-01

358

MERCURY ADSORPTION STOICHIOMETRY OF CERAMIC AND ACTIVATED CARBON FROM AQUEOUS PHASE UNDER DIFFERENT pH AND TEMPERATURE  

Microsoft Academic Search

Experiment was performed to draw a mercury adsorption stoichiometry of ceramic and activated carbon from aqueous phase in two parts - first part dealt with the effect of three different pH - 4, 7 and 10, whereas second part was designed to determine the effect of three temperatures - 15, 25 and 35C. SEM-EDS analysis of adsorbents clearly showed highly

J. N. Bhakta; K. Yamasaki; Y. Munekage

359

A two-dimensional finite-difference solution for the temperature distribution in a radial gas turbine guide vane blade  

NASA Technical Reports Server (NTRS)

A two-dimensional finite difference numerical technique is presented to determine the temperature distribution in a solid blade of a radial guide vane. A computer program is written in Fortran IV for IBM 370/165 computer. The computer results obtained from these programs have a similar behavior and trend as those obtained by experimental results.

Hosny, W. M.; Tabakoff, W.

1975-01-01

360

Differential Listeria monocytogenes Strain Survival and Growth in Katiki, a Traditional Greek Soft Cheese, at Different Storage Temperatures  

Microsoft Academic Search

Katiki Domokou is a traditional Greek cheese, which has received the Protected Designation of Origin recognition since 1994. Its microfloras have not been studied although its structure and composition may enable (or even favor) the survival and growth of several pathogens, including Listeria monocytogenes. The persistence of L. monocytogenes during storage at different temperatures has been the subject of many

Dafni-Maria Kagkli; Vassilios Iliopoulos; Virginia Stergiou; Anna Lazaridou; George-John Nychas

2009-01-01

361

Seasonal differences in the current and temperature variability over the northern California shelf during the Coastal Ocean Dynamics Experiment  

Microsoft Academic Search

A long-term moored array was maintained over the northern California continental shelf from April 1981 to April 1983 as part of the Coastal Ocean Dynamics Experiment to determine the seasonal differences in the current and water temperature characteristics. The array consisted of two midshelf moorings and one upper slope mooring from April 1981 through July 1982 and one midshelf mooring

Steven J. Lentz; David C. Chapman

1989-01-01

362

Relationships Between the Bulk-Skin Sea Surface Temperature Difference, Wind, and Net Air-Sea Heat Flux.  

National Technical Information Service (NTIS)

The primary purpose of this project was to evaluate and improve models for the bulk-skin temperature difference to the point where they could accurately and reliably apply under a wide variety of environmental conditions. To accomplish this goal, work was...

W. J. Emery S. L. Castro

2002-01-01

363

Factors affecting the wettability of different surface materials with vegetable oil at high temperatures and its relation to cleanability  

NASA Astrophysics Data System (ADS)

The main aim of the work was to investigate the wettability of different surface materials with vegetable oil (olive oil) over the temperature range of 25-200 C to understand the differences in cleanability of different surfaces exposed to high temperatures in food processes. The different surface materials investigated include stainless steel (reference), PTFE (polytetrafluoroethylene), silicone, quasicrystalline (Al, Fe, Cr) and ceramic coatings: zirconium oxide (ZrO2), zirconium nitride (ZrN) and titanium aluminum nitride (TiAlN). The ceramic coatings were deposited on stainless steel with two different levels of roughness. The cosine of the contact angle of olive oil on different surface materials rises linearly with increasing temperature. Among the materials analyzed, polymers (PTFE, silicone) gave the lowest cos ? values. Studies of the effect of roughness and surface flaws on wettability revealed that the cos ? values increases with increasing roughness and surface flaws. Correlation analysis indicates that the measured contact angle values gave useful information for grouping easy-clean polymer materials from the other materials; for the latter group, there is no direct relation between contact angle and cleanability. In addition to surface wettability with oil many other factors such as roughness and surface defects play an essential role in determining their cleanability.

Ashokkumar, Saranya; Adler-Nissen, Jens; Mller, Per

2012-12-01

364

The Effect of Melia azadirchta Fruit extract on eggs, embryo and Juveniles of the fresh water snail Physa acuta ( Draparnaud) , at different experimental temperatures  

Microsoft Academic Search

The influence of the alcoholic extract of Melia azadirchta fruit of different concentrations at different experimental temperatures on the fecundity, embryonic development and hatching of Physa. acuta was investigated. There was a significant difference between the embryonic development reared at relatively higher temperature ( 32C 2 ) and those reared at low temperature ( 10 C 2 ) ,

Talib Hussen Ali

365

High temperature oxidation of Fe 9Cr 1Mo steel in stagnant liquid lead bismuth at several temperatures and for different lead contents in the liquid alloy  

NASA Astrophysics Data System (ADS)

This research project deals with the feasibility studies concerning the construction of an hybrid reactor for the transmutation of long-lived radioactive wastes. In this context, the liquid lead-bismuth eutectic (LBE) is considered to be a good candidate for the spallation target material needed for the neutrons production necessary to the transmutation. In this hybrid reactor, the LBE, which is enclosed in a T91 (Fe-9%Cr) steel container, can induce corrosion concerns. If the oxygen content dissolved in Pb-Bi is higher than the needed content for magnetite formation, corrosion proceeds by oxidation of the steel. Previously, specific results were reported, obtained in stagnant liquid LBE at 470 C. An analytical model taking into account the oxide layer structure has been carried out. It involves iron, oxygen and chromium bulk diffusion and diffusion via preferential paths such as liquid lead-bismuth nano-channels incorporated in the oxide layer structure and grain boundaries. In this paper, experimental results on corrosion kinetics, obtained at different temperatures with different percentages of lead in the lead-bismuth alloy, are presented. The model, adapted to the different experimental conditions, is compared to these kinetics and to experimental points coming from the literature at different temperatures in LBE, in pure lead and in pure bismuth.

Martinelli, L.; Dufrenoy, T.; Jaakou, K.; Rusanov, A.; Balbaud-Clrier, F.

2008-06-01

366

Temperature dependence of APD-based PET scanners  

SciTech Connect

Purpose: Solid state detectors such as avalanche photodiodes (APDs) are increasingly being used in PET detectors. One of the disadvantages of APDs is the strong decrease of their gain factor with increasing ambient temperature. The light yield of most scintillation crystals also decreases when ambient temperature is increased. Both effects lead to considerable temperature dependence of the performance of APD-based PET scanners. In this paper, the authors propose a model for this dependence and the performance of the LabPET8 APD-based small animal PET scanner is evaluated at different temperatures.Methods: The model proposes that the effect of increasing temperature on the energy histogram of an APD-based PET scanner is a compression of the histogram along the energy axis. The energy histogram of the LabPET system was acquired at 21 C and 25 C to verify the validity of this model. Using the proposed model, the effect of temperature on system sensitivity was simulated for different detector temperature coefficients and temperatures. Subsequently, the effect of short term and long term temperature changes on the peak sensitivity of the LabPET system was measured. The axial sensitivity profile was measured at 21 C and 24 C following the NEMA NU 4-2008 standard. System spatial resolution was also evaluated. Furthermore, scatter fraction, count losses and random coincidences were evaluated at different temperatures. Image quality was also investigated.Results: As predicted by the model, the photopeak energy at 25 C is lower than at 21 C with a shift of approximately 6% per C. Simulations showed that this results in an approximately linear decrease of sensitivity when temperature is increased from 21 C to 24 C and energy thresholds are constant. Experimental evaluation of the peak sensitivity at different temperatures showed a strong linear correlation for short term (2.32 kcps/MBq/C = 12%/C, R = ?0.95) and long term (1.92 kcps/MBq/C = 10%/C , R = ?0.96) temperature changes. Count rate evaluation showed that although the total count rate is consistently higher at 21 C than at 24 C for different source activity concentrations, this is mainly due to an increase in scattered and random coincidences. The peak total count rate is 400 kcps at both temperatures but is reached at lower activity at 21 C. The peak true count rate is 138 kcps (at 100 MBq) at 21 C and 180 kcps (at 125 MBq) at 24 C. The peak noise equivalent count rate is also lower at 21 C (70 kcps at 70 MBq) than at 24 C (100 kcps at 100 MBq). At realistic activity levels, the scatter fraction is lower at higher temperatures, but at the cost of a strong decrease in true count rate.Conclusions: A model was proposed for the temperature dependence of APD-based PET scanners and evaluated using the LabPET small animal PET scanner. System sensitivity and count rate performance are strongly dependent on ambient temperature while system resolution is not. The authors results indicate that it is important to assure stable ambient temperature to obtain reproducible results in imaging studies with APD-based PET scanners.

Keereman, Vincent; Van Holen, Roel; Vandenberghe, Stefaan; Vanhove, Christian [MEDISIP, Department of Electronics and Information Systems, Ghent University-iMinds-IBiTech, De Pintelaan 185, B-9000 Ghent (Belgium)] [MEDISIP, Department of Electronics and Information Systems, Ghent University-iMinds-IBiTech, De Pintelaan 185, B-9000 Ghent (Belgium)

2013-09-15

367

Dislocation structures in zirconium and zircaloy-4 fatigued at different temperatures  

Microsoft Academic Search

The development of characteristic dislocation structures in pure zirconium and zircaloy-4 fatigued under pull-push strain\\u000a control as the testing temperature and the cyclic strain range varied was examined using a thin-foil transmission electron\\u000a microscopy (TEM) technique. The slip planes and the twinning planes were determined by a standard stereographic trace analysis\\u000a technique. The first-order prismatic slip {10\\u000a $$\\\\bar 1$$\\u000a 0}

Lin Xiao; Haicheng Gu

1997-01-01

368

Carbon mineralization of flooded boreal soil and vegetation under different temperature and oxygen conditions  

NASA Astrophysics Data System (ADS)

Flooding of terrestrial ecosystems significantly alters carbon (C) mineralization rates, which results in increasing emissions of carbon dioxide (CO2) and methane (CH4). To better understand the changes after water impoundment, C mineralization under flooded conditions needs to be investigated. This study investigates CO2 and CH4 fluxes from flooded boreal soil and vegetation, compares them to the fluxes of non- flooded treatment, and examines how environmental factors affect the fluxes. We conducted short-term in vitro experiments using boreal forest soil (FH layer), peat soil (0 to 5 and 5 to 15 cm) layer, and black spruce needles and small twigs, and shrub, sedge, lichen, and moss tissues. Flooded samples were incubated in 1- L Mason jars without light, under three temperatures (5, 12, and 24degC) and 0 and 50 percent of ambient oxygen (O2) concentration, and non-flooded ones were incubated in 1-L plastic containers under same light and temperature conditions to those of flooded samples and ambient oxygen concentration. We collected gas samples after flushing with nitrogen gas and air, and the fluxes of CO2 and CH4 were determined by gas chromatography. The average CO2 and CH4 fluxes in all materials were 200 and 0.8 microgram C/g organic matter/day, with smaller CO2 fluxes and larger CH4 fluxes than the fluxes of non-flooding (CO2 and CH4: 370 and 0.2 microgram C/g organic matter/day). Among the flooded samples, forest and peatland ground vegetation showed much high CO2 fluxes, and peat soils released more CH4 than other materials. Higher temperatures increased emissions of both CO2 and CH4, and the lower O2 concentration increased CH4 emissions. These results suggest the flooded vegetation and peat soil largely contribute to the total C emission in the flooded ecosystem and that spatial and temporal variability in CO2 and CH4 emissions can be related to substrate type, temperature and O2 concentration.

Kim, Y.; Ullah, S.; Roulet, N.; Moore, T.

2009-05-01

369

Synthesis of zeolite from Italian coal fly ash: Differences in crystallization temperature using seawater instead of distilled water  

SciTech Connect

In this study Italian coal fly ash was converted into several types of zeolite in laboratory experiments with temperatures of crystallization ranging from 35 up to 90 deg. C. Distilled and seawater were used during the hydrothermal synthesis process in separate experiments, after a pre-treatment fusion with NaOH. The results indicate that zeolites could be formed from different kind of Italian coal fly ash at low temperature of crystallization using both distilled and seawater. SEM data and the powder patterns of X-ray diffraction analysis show that faujasite, zeolite ZK-5 and sodalite were synthesized when using both distilled and seawater; zeolite A crystallized only using distilled water. In particular the experiments indicate that the synthesis of zeolite X and zeolite ZK-5 takes place at lower temperatures when using seawater (35 and 45 deg. C, respectively). The formation of sodalite is always competitive with zeolite X which shows a metastable behaviour at higher temperatures (70-90 deg. C). The chemical composition of the fly ash source could be responsible of the differences on the starting time of synthesized zeolite with distilled water, in any case our data show that the formation of specific zeolites takes place always at lower temperatures when using seawater.

Belviso, Claudia, E-mail: belviso@imaa.cnr.i [Laboratory of Environmental and Medical Geology, IMAA-CNR, Tito Scalo (Italy); Cavalcante, Francesco; Fiore, Saverio [Laboratory of Environmental and Medical Geology, IMAA-CNR, Tito Scalo (Italy)

2010-05-15

370

Combination of differential growth at two different temperatures with a quantitative real-time polymerase chain reaction to determine temperature-sensitive phenotype of Mycoplasma synoviae.  

PubMed

Mycoplasma synoviae infections result in significant economic losses in the chicken and turkey industries. A commercially available live temperature-sensitive (ts (+)) vaccine strain MS-H has been found to be effective in controlling M. synoviae infections in commercial layer and broiler breeder farms in various countries, including Australia. Detection and differentiation of MS-H from field strains (ts (-)) and from ts (-) MS-H reisolates in vaccinated flocks is vital in routine flock status monitoring. At present microtitration is the only available technique to determine the ts phenotype of M. synoviae. This technique is time consuming and not amenable to automation. In the present study, a quantitative real-time polymerase chain reaction (Q-PCR) was combined with simultaneous culturing of M. synoviae at two different temperatures (33C and 39.5C) to determine the ts phenotype of 22 Australian M. synoviae strains/isolates. The M. synoviae type strain WVU-1853 was also included for comparison. A ratio of the copy numbers of the variable lipoprotein haemagglutinin (vlhA) gene at the two temperatures was calculated and a cut-off value was determined and used to delineate the ts phenotype. In all M. synoviae strains/isolates tested in this study, the ts phenotype determined using Q-PCR was in agreement with that determined using conventional microtitration. Combination of Q-PCR with differential growth at two different temperatures is a rapid, reliable and accurate technique that could be used as an effective tool in laboratories actively involved in ts phenotyping of M. synoviae strains/isolates. PMID:23581447

Shahid, Muhammad A; Ghorashi, Seyed A; Agnew-Crumpton, Rebecca; Markham, Philip F; Marenda, Marc S; Noormohammadi, Amir H

2013-04-01

371

Solute descriptors for characterizing retention properties of open-tubular columns of different selectivity in gas chromatography at intermediate temperatures.  

PubMed

An iteration procedure is used to optimize the solute descriptors for 94 compounds suitable for characterizing the retention properties of open-tubular columns for gas chromatography in the intermediate temperature range of 160-240 degrees C. These solute descriptors are used to calculate the system constants of the solvation parameter model for nine open-tubular columns (SPB-Octyl, HP-5, Rtx-440, Rxi-50, Rtx-OPP, DB-1701, DB-225, HP-Innowax, and HP-88) at increments of 20 degrees C from 160 to 240 degrees C. The optimized descriptors afford a two- to three-fold improvement in the fit to the retention model compared with literature values as determined by the standard deviation of the difference between the model predicted and experimental retention factors (log k). Combining literature values for the system constants at lower temperatures (60-140 degrees C) with those obtained here allowed system maps to be constructed for the nine columns over the full temperature range of 60-240 degrees C. For a wide temperature range the system maps indicate that the relationship between the system constants and temperature is non-linear and that polar interactions are likely to be important in relative and absolute terms to quite high temperatures. PMID:18501372

Atapattu, Sanka N; Poole, Colin F

2008-06-27

372

Strain build-up in SiC implanted at different temperatures  

NASA Astrophysics Data System (ADS)

Single crystals of 4H-SiC were implanted with helium ions at temperatures of 400 and 700 C in a large range of fluences. The damage accumulation versus fluence was studied through the tensile elastic strain determined by using X-ray diffraction measurements. Results were analyzed via the multi-step damage accumulation model. At low dose (step 1) the strain can be described assuming a thermally activated process with low activation energy. Damage cross-sections, independent of implantation temperature, for interstitial-type defects were determined. With increasing dose, the contribution of other defects arises leading to an accelerated strain build-up namely the second step of the disordering process. However, in this regime, the strain cannot be fully described due to others operative mechanisms such as the formation of tiny bubbles under severe conditions of implantation. The formation of bubbles accelerates the development of the elastic strain. The values of damage cross-sections show that only small clusters contribute to the tensile elastic strain.

Barbot, J.-F.; Beaufort, M.-F.; Declmy, A.

2014-05-01

373

Why COBE and CN spectroscopy cosmic background radiation temperature measurements differ, and a remedy  

NASA Astrophysics Data System (ADS)

In 2004, the cosmic background radiation (CBR) temperature T?(CN) determined from interstellar CN absorption spectra was found to be 50 20 mK higher than the COBE bolometer measured value. It was proposed that this was due, at least in part, to an error in the evaluation of the rotational components of the oscillator strengths of the rovibronic transitions corresponding to the CN B 2?+-X 2?+(0 - 0), R(0), R(1) and P(1) lines. Corrections to the standard Hnl-London (HL) rotational line intensity factors used were determined. New data on interstellar CN absorption show that T?(CN) is 29 2 mK greater than the latest value of the cosmological CBR temperature, T?(COBE) = 2.72548 0.00057 K. These new results and CN fluorescence lifetime data are shown to give similar derived values for improved HL corrections as well as providing further evidence for the intramolecular coupling between the relevant B 2?+ state rotational levels and close-lying levels of the A 2? state which invalidates the standard HL factors. Revised HL factors may be required in future T?(CN) measurements, in particular in high-redshift sites, which cannot be studied by bolometric means.

Leach, Sydney

2012-04-01

374

Parametric Evaluation of Large-Scale High-Temperature Electrolysis Hydrogen Production Using Different Advanced Nuclear Reactor Heat Sources  

SciTech Connect

High Temperature Electrolysis (HTE), when coupled to an advanced nuclear reactor capable of operating at reactor outlet temperatures of 800 C to 950 C, has the potential to efficiently produce the large quantities of hydrogen needed to meet future energy and transportation needs. To evaluate the potential benefits of nuclear-driven hydrogen production, the UniSim process analysis software was used to evaluate different reactor concepts coupled to a reference HTE process design concept. The reference HTE concept included an Intermediate Heat Exchanger and intermediate helium loop to separate the reactor primary system from the HTE process loops and additional heat exchangers to transfer reactor heat from the intermediate loop to the HTE process loops. The two process loops consisted of the water/steam loop feeding the cathode side of a HTE electrolysis stack, and the sweep gas loop used to remove oxygen from the anode side. The UniSim model of the process loops included pumps to circulate the working fluids and heat exchangers to recover heat from the oxygen and hydrogen product streams to improve the overall hydrogen production efficiencies. The reference HTE process loop model was coupled to separate UniSim models developed for three different advanced reactor concepts (a high-temperature helium cooled reactor concept and two different supercritical CO2 reactor concepts). Sensitivity studies were then performed to evaluate the affect of reactor outlet temperature on the power cycle efficiency and overall hydrogen production efficiency for each of the reactor power cycles. The results of these sensitivity studies showed that overall power cycle and hydrogen production efficiencies increased with reactor outlet temperature, but the power cycles producing the highest efficiencies varied depending on the temperature range considered.

Edwin A. Harvego; Michael G. McKellar; James E. O'Brien; J. Stephen Herring

2009-09-01

375

Comparison of bacterial community changes in fermenting kimchi at two different temperatures using a denaturing gradient gel electrophoresis analysis.  

PubMed

A polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) technique followed by sequencing of the 16S rDNA fragments eluted from the bands of interest on denaturing gradient gels was used to monitor changes in the bacterial microflora of two commercial kimchi, salted cabbage, and ingredient mix samples during 30 days of fermentation at 4C and 10C. Leuconostoc (Lc.) was the dominant lactic acid bacteria (LAB) over Lactobacillus (Lb.) species at 4C. Weissella confusa was detected in the ingredient mix and also in kimchi samples throughout fermentation in both samples at 4C and 10C. Lc. gelidum was detected as the dominant LAB at 4C in both samples. The temperature affected the LAB profile of kimchi by varing the pH, which was primarily caused by the temperature-dependent competition among different LAB species in kimchi. At 4C, the sample variations in pH and titratable acidity were more conspicuous owing to the delayed growth of LAB. Temperature affected only initial decreases in pH and initial increases in viable cell counts, but affected both the initial increases and final values of titratable acidity. The initial microflora in the kimchi sample was probably determined by the microflora of the ingredient mix, not by that of the salted cabbage. The microbial distributions in the samples used in this study resembled across the different kimchi samples and the different fermentation temperatures as the numbers of LAB increased and titratable acidity decreased. PMID:23314371

Hong, Yeun; Yang, Hee-Seok; Chang, Hae-Choon; Kim, Hae-Yeong

2013-01-01

376

Accumulation of trace metals in the embryos and hatchlings of Chelonia mydas from Peninsular Malaysia incubated at different temperatures.  

PubMed

A variety of trace metals were measured in the egg contents of three clutches of Chelonia mydas collected from Kuala Terengganu state in Peninsular Malaysia. We quantified Mn, Cu, Zn, Se (essential trace metals) and As (anthropogenic pollutant) at several developmental stages obtained by incubating eggs at two different temperatures (27 C and 31 C). The incubation temperatures were chosen because they produce predominantly male or predominantly female hatchlings, respectively. The eggs were removed from the sand and washed before being placed in incubators, to ensure that the only possible source of the detected metals was maternal transfer. Other metals: Mo, Co, Ni, Cd, Sn, Sb, Hg, Tl and Pb (all non-essential metals) were detected at concentrations below the lower limit of quantitation (LLOQ). Trace metal concentrations, particularly [Zn], increased during development, other metals (Cu, As, Se and Cr) accumulated to a lesser degree than zinc but no significant differences were observed between the incubation temperatures at any stage of incubation. To date, only a few studies on trace metals in turtle embryos and hatchlings have been reported; this study will provide basic knowledge on the accumulation of trace metals during development at two different incubation temperatures. PMID:23500829

Ikonomopoulou, Maria P; Olszowy, Henry; Francis, Rod; Ibrahim, Kamarruddin; Whittier, Joan

2013-04-15

377

The Effect of Simulating Different Intermediate Host Snail Species on the Link between Water Temperature and Schistosomiasis Risk  

PubMed Central

Introduction A number of studies have attempted to predict the effects of climate change on schistosomiasis risk. The importance of considering different species of intermediate host snails separately has never previously been explored. Methods An agent-based model of water temperature and Biomphalaria pfeifferi population dynamics and Schistosoma mansoni transmission was parameterised to two additional species of snail: B. glabrata and B. alexandrina. Results Simulated B. alexandrina populations had lower minimum and maximum temperatures for survival than B. pfeifferi populations (12.529.5C vs. 14.031.5C). B. glabrata populations survived over a smaller range of temperatures than either B. pfeifferi or B. alexandrina (17.0C29.5C). Infection risk peaked at 16.5C, 25.0C and 19.0C respectively when B. pfeifferi, B. glabrata and B. alexandrina were simulated. For all species, infection risk increased sharply once a minimum temperature was reached. Conclusions The results from all three species suggest that infection risk may increase dramatically with small increases in temperature in areas at or near the currents limits of schistosome transmission. The effect of small increases in temperature in areas where schistosomiasis is currently found will depend both on current temperatures and on the species of snail acting as intermediate host(s) in the area. In most areas where B. pfeifferi is the host, infection risk is likely to decrease. In cooler areas where B. glabrata is the host, infection risk may increase slightly. In cooler areas where B. alexandrina is the host, infection risk may more than double with only 2C increase in temperature. Our results show that it is crucial to consider the species of intermediate host when attempting to predict the effects of climate change on schistosomiasis.

McCreesh, Nicky; Booth, Mark

2014-01-01

378

Thickness effect on structure and properties of ZAO thin films by RF magnetron sputtering at different substrate temperatures  

NASA Astrophysics Data System (ADS)

Al-doped ZnO (ZAO) films, having film thickness of about 50-1200 nm, were deposited at substrate temperature of 100-300 C by radio-frequency magnetron sputtering. Structural, electrical, and optical properties of as-deposited ZAO films have been studied as a function of film thickness and substrate temperature. The investigation of X-ray diffraction indicates that the crystalline quality of the film improves and its stress relaxes with increasing film thickness or substrate temperature, and preferred (0 0 2) orientation is found at substrate temperature above 100 C. By the observation under scanning electron microscope, columnar structure can be obviously observed from cross-section of the films with increasing film thickness at substrate temperature above 100 C; the surface morphology can exhibit nanocrystalline, honeycomb, or hillock structure, depending on film thickness and substrate temperature. Hall effect measurements reveal that the decrease of resistivity of the film is generally accompanied by the increase of carrier concentration and mobility with increasing film thickness or substrate temperature. It is speculated that the main scattering mechanism in as-deposited ZAO films is intercrystallite boundary scattering. The transmission spectra measurements of ZAO films indicate that average transmittance between 400 and 800 nm decreases from about 86% to 70% with increase in film thickness. The obtained energy gap ( Eg) of the films at different substrate temperatures is found in order of 200 C>300 C>100 C, which can be attributed to high carrier concentration and compressive stress at 200 C, but markedly low carrier concentration at 100 C. With increase in film thickness, the decrease in compressive stress and/or increase in crystallite size result in the decreased or unchanged tendency of Eg of the films although the carrier concentration increases.

Zhu, B. L.; Zhu, S. J.; Wang, J.; Wu, J.; Zeng, D. W.; Xie, C. S.

2011-07-01

379

Effect of disorder on carrier transport in ZnO thin films grown by atomic layer deposition at different temperatures  

NASA Astrophysics Data System (ADS)

We have grown ~200 nm thick ZnO films on (0001) sapphire substrates using atomic layer deposition at different substrate temperatures ranging from ~150 to 350 C. X-ray diffraction and photoluminescence spectra of these films showed that crystalline and compositional native defects were strongly dependent on the substrate temperature. Room temperature Hall measurement showed that all the films were degenerate with carrier concentration exceeding the Mott's critical density nc required for metallic conduction. The lowest value of room temperature resistivity ~3.6 10-3 ? cm was achieved for the film deposited at ~200 C, which had an estimated carrier concentration ~5.7 1019 cm-3 and mobility ~30 cm2/V s. The films deposited both below and above ~200 C showed increased resistivity and decreased mobility presumably due to the intensified defects and deteriorated crystalline quality of these films. To investigate the effect of disorder on the underlying charge transport mechanisms in these films, the electrical resistivity was measured in the temperature range of ~4.2 to 300 K. The films grown at ~150, 300, and 350 C were found to be semiconducting in the entire range of the measurement temperature due to the intensified disorder which impeded the metallic transport in these films. However, the films grown at ~200 and 250 C showed a transition from metallic to semiconducting transport behaviour at lower temperatures due to the reduced defects and improved crystalline quality of these films. The observed semiconducting behaviour below the transition temperature for these films could be well explained by considering quantum corrections to the Boltzmann conductivity which includes the effect of disorder induced weak localization and coulomb electron-electron interactions.

Saha, D.; Das, Amit. K.; Ajimsha, R. S.; Misra, P.; Kukreja, L. M.

2013-07-01

380

Crack resistance of aluminum composite under shock loading at different temperatures  

SciTech Connect

The paper presents the technique of study of aluminum composite K{sub 1d} crack resistance at shock loading at T={minus}50{divided_by}300{degree}C. The technique is based on application of split Hopkinson bars and plane specimen for axial wedging. Heating of specimens was carried out by electric heater, cooling{emdash}by vapours of liquid nitrogen. Specimens from aluminum composite A 359 (20 vol.{percent} SiC) of the firm DURAL were tested. K{sub 1d} values were obtained at mentioned temperatures in the interval of loading rates {dot K}{sub 1}=(0.1{minus}0.28){center_dot}10{sup 6}MPa{center_dot}m{sup 1}{sup 2}s{sup {minus}1}. {copyright} {ital 1998 American Institute of Physics.}

Novikov, S.A.; Pushkov, V.A.; Sinitsyn, V.A.; Gray, G.T. III [Russian Federal Nuclear Center---VNIIEF, 607190, Sarov, Nizhni Novgorod region (Russia)]|[Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

1998-07-01

381

Crack resistance of aluminum composite under shock loading at different temperatures  

SciTech Connect

The paper presents the technique of study of aluminum composite K{sub 1d} crack resistance at shock loading at T=-50 divide 300 deg. C. The technique is based on application of split Hopkinson bars and plane specimen for axial wedging. Heating of specimens was carried out by electric heater, cooling--by vapours of liquid nitrogen. Specimens from aluminum composite A 359 (20 vol. % SiC) of the firm DURAL were tested. K{sub 1d} values were obtained at mentioned temperatures in the interval of loading rates K{sub 1}=(0.1-0.28){center_dot}10{sup 6} MPa{center_dot}m{sup 1} {sup 2}s{sup -1}.

Novikov, S. A.; Pushkov, V. A.; Sinitsyn, V. A.; Gray, G. T. III [Russian Federal Nuclear Center-VNIIEF, 607190, Sarov, Nizhni Novgorod region (Russian Federation); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

1998-07-10

382

Age differences in the associations between felt temperatures and color choices.  

PubMed

Thirty-six subjects, twelve each at 6, 12, and 18 years of age, were asked which of four colors (blue, green, yellow, or red) they were reminded of by each of four temperatures (containers at 4, 23, 35, or 45 deg C). More 18-year-olds than expected by chance made each of the conventional associations: hot/red, warm/yellow, cool/green, cold/blue. The 12-year-olds reliably made the hot/red association but none of the others. No more 6-year-olds than expected by chance made any of the conventional associations. The results suggest that the conventional associations are founded on a loosely held cultural norm rather than on an evolutionary or physiological basis. PMID:1236563

Morgan, G A; Goodson, F E; Jones, T

1975-03-01

383

Stability of oxide film formed at different temperatures on Alloy 600 in lithiated environment  

NASA Astrophysics Data System (ADS)

The nickel base alloys are susceptible to localized corrosion attack and the major contributing factor in these corrosion mechanisms is the oxide film formed on the alloy. The chromium content in the oxide film determines its stability against localized attack that act as precursors for the initiation of stress corrosion cracking (SCC) in the material. The present study aimed at optimizing the hot conditioning parameter by varying the temperature of oxide formation for minimum ion release rate during reactor operation. The surface and in-depth compositional characterization of oxide film formed on Alloy 600 was carried out using micro-laser Raman spectroscopy (MLRS) and glow discharge quadrapole mass spectroscopy (GDQMS) respectively. The relative defect density of oxide films were studied using electrochemical impedance spectroscopy (EIS). The oxide film stability of Alloy 600 in chloride containing environment was correlated to chromium concentration in the film as well as relative defect density.

J. Abraham, Geogy; Kain, V.; Dey, G. K.; Raja, V. S.

2013-06-01

384

High-pressure high-temperature synthesis of magnesium diboride with different additions  

NASA Astrophysics Data System (ADS)

An increase of the critical current density in high-pressure synthesized (at 2 GPa, 800-900 C) MgB 2 was observed when some amount (2-10%) of powdered Ta, Ti or Zr was added to the initial mixture of Mg and B. As a result of high-pressure synthesis, the metallic additives transformed into hydrides, so the absorbed impurity hydrogen coming most likely from the materials of a high-pressure cell surrounded the synthesized samples. Blocks of high-pressure synthesized MgB 2 (with Ti additions) were for the first time used in an SC electromotor that demonstrated the efficiency similar to that of MT-YBCO bulk (at the same working temperature 15-20 K).

Prikhna, Tatiana; Gawalek, Wolfgang; Savchuk, Yaroslav; Sergienko, Nina; Moshchil, Viktor; Dub, Sergey; Sverdun, Vladimir; Kovalev, Leo; Penkin, Vladimir; Zeisberger, Matthias; Wendt, Michael; Fuchs, Gunter; Habisreuther, Tobias; Litzkendorf, Doris; Nagorny, Peter; Melnikov, Vladimir

2007-09-01

385

Cavitation erosion of silver plated coating at different temperatures and pressures  

NASA Astrophysics Data System (ADS)

Cavitation often occurs in inducer pumps used for space rockets. Silver plated coating on the inducer liner faces the damage of cavitation. Therefore, it is important to study about the cavitation erosion resistance for silver plated coating at several operating conditions in the inducer pumps. In this study, the cavitation erosion tests were carried for silver plated coating in deionized water and ethanol at several liquid temperatures (273K-400K) and pressures (0.10MPa-0.48MPa). The mass loss rate is evaluated in terms of thermodynamic parameter ? proposed by Brennen [9], suppression pressure p-pv (pv: saturated vapor pressure) and acoustic impedance ?c (?: density and c: sound speed). Cavitation bubble behaviors depending on the thermodynamic effect and the liquid type were observed by high speed video camera. The mass loss rate is formulated by thermodynamic parameter ?, suppression pressure p-pv and acoustic impedance ?c.

Hattori, Shuji; Motoi, Yoshihiro; Kikuta, Kengo; Tomaru, Hiroshi

2014-04-01

386

Field emission properties of diamond-like carbon films annealed at different temperatures  

NASA Astrophysics Data System (ADS)

Effect of annealing on the field emission properties of diamond-like carbon (DLC) films deposited by high power excime laser technique was studied. Raman spectrometry and X-ray photoelectron spectrometry (XPS) were used to determine the chemical bonding structural change of the annealed DLC films. It was found that the annealing transformed gradually DLC films into a graphitic structure as annealing temperature was increased to more than 600 C, simultaneously field emission properties of DLC films were enhanced markedly. Graphitization of DLC films induced by annealing caused the formation of a large fraction of sp 2 C in the DLC films, which played an important role in the enhancement of field emission properties for DLC films. Rich sp 2 C cluster acted as a conduction part in the films could increase the conductivity of DLC films and lower the effective work function of DLC films, consequently improve field emission properties of DLC films.

Li, J. J.; Gu, C. Z.; Peng, H. Y.; Wu, H. H.; Zheng, W. T.; Jin, Z. S.

2005-09-01

387

Compensatory Growth of Grower Olive Flounder (Paralichthys olivaceus) with Different Feeding Regime at Suboptimal Temperature  

PubMed Central

Compensatory growth of grower olive flounder (Paralichthys olivaceus) was determined at suboptimal temperature (13.01.9C). Fifteen fish averaging 201.1 g per tank were distributed into 18 of 300 L flow-through tanks. Six treatments were prepared in triplicate: fish were hand-fed with an extruded pellet to apparent satiation once a day for 16 weeks (16 WF); and the other five groups of fish were hand-fed for 15, 14, 13, 12 and 10 weeks after 1-, 2-, 3-, 4- and 6-week feed deprivation, referred to as 15 WF, 14 WF, 13 WF, 12 WF and 10 WF, respectively. A linear relationship between body weight of fish and feed deprivation was observed: Y (Body weight of fish) = ?1.81X (Weeks of feed deprivation)+201.07, R2 = 0.83. Weight gain of grower olive flounder in 15 WF, 14 WF, 13 WF and 12 WF treatments was comparable to that of fish in 16 WF treatment, but lower than that of fish in 10 WF treatment. Specific growth rate of fish in 15 WF treatment was higher than that of fish in 16 WF, 14 WF and 10 WF treatments. Feed consumption of fish was not affected by feeding regime. Feed and protein efficiency ratios of fish in 15 WF treatment were higher than those of fish in 13 WF, 12 WF and 10 WF treatments. Grower olive flounder could achieve full compensatory growth when fish were daily fed for 12 weeks after 4-week feed deprivation at suboptimal temperature.

Cho, S. H.; Kim, K. T.; Choi, I. C.; Jeon, G. H.; Kim, D. S.

2012-01-01

388

The roles of temperature and water vapor at different stages of the polar mesospheric cloud season  

NASA Astrophysics Data System (ADS)

Temperature, or alternatively, saturation vapor pressure (PSAT), dominantly controls the polar mesospheric cloud (PMC) seasonal onset and termination, characterized by a strong anticorrelated relationship between the Solar Occultation for Ice Experiment (SOFIE)-observed PMC frequency and PSAT on intraseasonal time scales. SOFIE is highly sensitive to weak clouds and can obtain a nearly full spectrum of PMCs. Both the SOFIE PMC frequency and PSAT indicate a rapid onset and termination of the season. Compared to PSAT, the water vapor partial pressure (PH2O) exhibits only a slight increase from before to after the start of the season. We are able to use the PSAT daily minimum and two averaged PH2O levels taken before and after the solstice, respectively, to estimate the start and end days of the PMC season within 1-2 days uncertainty. SOFIE ice mass density and its relationship to PH2O and PSAT are examined on intraseasonal scales and for two extreme conditions, i.e., strong and weak cloud cases. In the strong cloud case, such as those bright clouds that occur during the core of the season, PH2O far exceeds PSAT and dominantly controls the ice mass density variation, while in the weak cloud case, such as those clouds that occur at the start and end of the season, PH2O and PSAThave comparable magnitudes, vary in concert, and have similar effects on the ice mass density variation. These results suggest that the long-term brightness trends reported by DeLand et al. (2007) are primarily driven by changes in water vapor (H2O), not temperature.

Rong, P. P.; Russell, J. M., III; Hervig, M. E.; Bailey, S. M.

2012-02-01

389

Assessment of Red Blood Cell Parameters and Peripheral Smear at Different Temperatures in Case of Cold Agglutination Disease  

PubMed Central

Cold agglutination disease (CAD) is characterized by an auto-antibody which is able to agglutinate red blood cells (RBCs) at temperatures lower than that of the body, and subsequently to activate the complement system responsible for lysis of RBCs. Patients show hemolytic anemia of varying degrees of severity, which arise or worsen upon exposure to low temperatures. We describe a case who presented with fever and symptoms of asthenia. His investigations yielded bizarre RBC parameters which led to suspicion of a rare CAD, which was confirmed on reviewing RBC parameters, peripheral smear and direct Coomb's test at different temperatures. Hence, we suggest assessment of bizarre RBC parameters and peripheral smear can help in laboratory testing and diagnosis of CAD. It should also not pose embarrassment in laboratory testing to the pathologist for making an early and accurate diagnosis, thus emphasizing the need for an early treatment of CAD.

Gupta, V

2014-01-01

390

Effect of Sodium Bicarbonate Supplementation on Carcass Characteristics of Lambs Fed Concentrate Diets at Different Ambient Temperature Levels  

PubMed Central

The objective of this study was to investigate the influence of ambient temperatures on carcass characteristics of lambs fed concentrate diets with or without NaHCO3 supplementation. A slaughter study was carried on 12 male Black Belly Barbados lambs randomly drawn from a growth trial (35 weeks). The lambs were divided into four equal groups and allotted in a 22 factorial design. The lambs were allotted at random to two dietary treatments of a basal diet (35:65 roughage:concentrate) or basal diet supplemented with 4% NaHCO3 at different ambient temperatures (20C and 30C) in an environment controlled chamber for 10 days. Lambs were slaughtered for carcass evaluation at about 262 days of age (245 days of growth trial, 7 days adaptation and 10 days of experimental period). Ambient temperature had significant (p<0.05, p<0.05, p<0.01, and p<0.001) effects on meat color from the ribeye area (REA), fat, leg and longissimus dorsi muscles with higher values recorded for lambs in the lower temperature group than those from the higher ambient temperature group. Significant differences (p<0.05) in shear force value (kg/cm2) recorded on the leg muscles showed higher values (5.32 vs 4.16) in lambs under the lower ambient temperature group compared to the other group. Dietary treatments had significant (p<0.01, p<0.01, and p<0.05) effects on meat color from the REA, fat, and REA fat depth (cm2) with higher values recorded for lambs in the NaHCO3 supplementation group than the non supplemented group. Similarly, dietary treatments had significant differences (p<0.05) in shear force value (kg/cm2) of the leg muscles with the NaHCO3 groups recording higher (5.30 vs 4.60) values than those from the other group. Neither ambient temperature nor dietary treatments had any significant (p>0.05) effects on pH, and water holding capacity on both muscles. These results indicated that NaHCO3 supplementation at low ambient temperatures had caused an increase in carcass characteristics leading to significant effect on meat quality.

Jallow, Demba B.; Hsia, Liang Chou

2014-01-01

391

Equilibrium adsorption studies of some aromatic pollutants from dilute aqueous solutions on activated carbon at different temperatures  

SciTech Connect

Aqueous solutions of phenol, p-chlorophenol, and p-nitrophenol have been used to determine the adsorption isotherm for single solute systems on activated carbon at different temperatures. The experimental program has been conducted to investigate the influence of concentration and temperature. All the reported equilibrium isotherm equations have been tried on present and published experimental data. A generalized isotherm equation which was proposed by Khan et al. and tested for bi-solute adsorption data has been modified for single-solute system. The temperature dependency has also been incorporated into a generalized equation. It has been noticed that the Radke and Prausnitz and generalized isotherm equations could represent the entire data with a minimum average percentage error. The influence of different adsorbents, sorbate concentrations, and pH of aqueous solutions has also been discussed in detail. The temperature dependency has been investigated using both the Dubinin-Astakov and the modified generalized equation. The generalized equation describes the experimental and published data adequately and provides a single value of differential molar heat of adsorption, {Delta}H{sub ads}, for a single solute adsorption system. The Dubinin-Astakov isotherm equation has shown an increasing trend of {Delta}H{sub ads} as the loading of adsorbent has increased.

Khan, A.R.; Ataullah, R.; Al-Haddad, A. [Kuwait Univ., Safat (Kuwait). Dept. of Chemical Engineering] [Kuwait Univ., Safat (Kuwait). Dept. of Chemical Engineering

1997-10-01

392

Production of biomass and nutraceutical compounds by Spirulina platensis under different temperature and nitrogen regimes.  

PubMed

The cyanobacterium Spirulina platensis has been used by humans because of its nutritional and possibly medicinal effects. Our study evaluated the influence of temperature and nitrogen concentration in the medium on the production of biomass by this cyanobacterium and the biomass composition in protein, lipid and phenolic compounds. We found that at 35 degrees C there was a negative effect on biomass production but a positive effect on the production of protein, lipids and phenolics, the highest levels of these compounds being obtained in Zarrouk's medium containing 1.875 or 2.500 g l(-1) sodium nitrate. Higher biomass densities and productivity were obtained at 30 degrees C than at 35 degrees C, but nitrogen concentration appeared to have no effect on the amount of protein, lipid or phenolics, indicating that at 30 degrees C the concentration of sodium nitrate in Zarrouk's medium (2.50 g l(-1)) can be reduced without loss of productivity, an important cost-saving factor in large-scale cultivation. PMID:17070035

Colla, Luciane Maria; Oliveira Reinehr, Christian; Reichert, Carolina; Costa, Jorge Alberto Vieira

2007-05-01

393

Flight performance of the soybean aphid, Aphis glycines (Hemiptera: Aphididae) under different temperature and humidity regimens.  

PubMed

The soybean aphid, Aphis glycines (Matsumura), is native to eastern Asia and has recently invaded North America, where it is currently the most important insect pest of soybeans. The soybean aphid has spread rapidly within North America, presumably through a combination of active and passive (wind-aided) flight. Here, we studied the active flight potential of A. glycines under a range of environmental conditions using an aphid flight mill. Winged (alate) A. glycines were tested on a specially designed 32-channel, computer-monitored flight mill system. Aphids that were 12-24 h old exhibited the strongest flight behavior, with average flight durations of 3.3-4.1 h, which represented flight distances of 4.6-5.1 km. After the age of 72 h, A. glycines flight performance rapidly declined. The optimum temperature range for flight was 16-28 degrees C, whereas optimum relative humidity was 75%. Our findings show that A. glycines posseses a fairly strong active flight aptitude (ability and inclination) and point to the possibility of flight initiation under a broad range of environmental conditions. These results have the potential to aid forecasting and management protocols for A. glycines at the landscape level. PMID:18419900

Zhang, Ying; Wang, Limin; Wu, Kongming; Wyckhuys, Kris A G; Heimpel, George E

2008-04-01

394

SAXS/DSC/WAXD study of temperature evolution in nanocomposite polymer electrolytes with different nanofillers.  

PubMed

Polymer electrolytes are nanostructured materials which are very attractive components for batteries and opto-electronic devices. (PEO)8ZnCl2 polymer electrolytes were prepared from PEO and ZnCl2. The nanocomposites (PEO)8ZnCI2 themselves contained TiO2, Al2O3, MgO, ZnO and V2O5 nanograins. In this work, the influence of the Al2O3, MgO and V2O5 nanograins on the morphology and ionic conductivity of the nanocomposite was systematically studied by transmission small-angle X-ray scattering simultaneously recorded with wide-angle X-ray diffraction and differential scanning calorimetry at the synchrotron ELETTRA (Trieste, Italy). These three measurement methods yielded insight into the temperature-dependent changes of the grains of the electrolyte. The heating and cooling rate was 0.5 degrees C/min. Environment friendly galvanic cells as well as solar cells of the second generation are to be constructed with such nanocomposite polymer as electrolyte. PMID:23421266

Turkovi?, A; Dubcek, P; Jurai?, K; Bernstorff, S

2012-11-01

395

Pyrolysis behavior of tire-derived fuels at different temperatures and heating rates.  

PubMed

Pyrolytic product distribution rates and pyrolysis behavior of tire-derived fuels (TDF) were investigated using thermogravimetric analyzer (TGA) techniques. A TGA was designed and built to investigate the behavior and products of pyrolysis of typical TDF specimens. The fundamental knowledge of TGA analysis and principal fuel analysis are applied in this study. Thermogravimetry of the degradation temperature of the TDF confirms the overall decomposition rate of the volatile products during the depolymerization reaction. The principal fuel analysis (proximate and ultimate analysis) of the pyrolytic char products show the correlation of volatilization into the gas and liquid phases and the existence of fixed carbon and other compounds that remain as a solid char. The kinetic parameters were calculated using least square with minimizing sum of error square technique. The results show that the average kinetic parameters of TDF are the activation energy, E = 1322 +/- 244 kJ/mol, a pre-exponential constant of A = 2.06 +/- 3.47 x 10(10) min(-1), and a reaction order n = 1.62 +/- 0.31. The model-predicted rate equations agree with the experimental data. The overall TDF weight conversion represents the carbon weight conversion in the sample. PMID:16739798

Unapumnuk, Kessinee; Keener, Tim C; Lu, Mingming; Khang, Soon-Jai

2006-05-01

396

Mathematical models for growth in alligator (Alligator mississippiensis) embryos developing at different incubation temperatures.  

PubMed

A variety of model-based (growth models) and model-free (cubic splines, exponentials) equations were fitted using weighted-nonlinear least squares regression to embryonic growth data from Alligator mississippiensis eggs incubated at 30 and 33 degrees C. Goodness of fit was estimated using a chi 2 on the sum of squared, weighted residuals, and run and sign tests on the residuals. One of the growth models used (Preece & Baines, 1978) was found to be superior to the classical growth models (exponential, monomolecular, logistic, Gompertz, von Bertalanffy) and gave an adequate fit to all longitudinal measures taken from the embryonic body and embryonic mass. However, measurements taken from the head could not be fitted by growth models but were adequately fitted by weighted least squares cubic splines. Data for the stage of development were best fitted by a sum of 2 exponentials with a transition point. Comparison of the maximum growth rates and parameter values, indicated that the growth data at 30 degrees C could be scaled to 33 degrees C to multiplying the time by a scaling factor of 1.2. This is equivalent to a Q10 of about 1.86 or, after solving the Arrhenius equation, an E++ of 46.9 kJmol-1. This may be interpreted as indicating a common rate-limiting step in development at the 2 temperatures. PMID:7591979

Bardsley, W G; Ackerman, R A; Bukhari, N A; Deeming, D C; Ferguson, M W

1995-08-01

397

Point defects analysis of zinc oxide thin films annealed at different temperatures with photoluminescence, Hall mobility, and low frequency noise  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) thin films annealed at different temperatures were studied with photoluminescence (PL), electrical resistivity, Hall mobility, and 1/f noise spectroscopy. Relatively high electrical conductivity and carrier concentration in sample annealed at 400 C suggested the presence of ZnO interstitials. Rapid reduction in electrical conductivity and carrier concentration upon increasing the annealing temperature suggested that ZnO interstitials could be eliminated by high temperature annealing. Presence of G-R noise in sample annealed at 400 C indicated high level of electron trapping activities. Density of Zn vacancies acting as electron traps was estimated by Lorentzian fitting on the G-R noise. PL spectra exhibiting dominant green emission in all samples suggested the presence of Zn vacancies in high concentration. Yellow-orange emission in PL in samples annealed at 600 C and below indicated the presence of O interstitials, while the same emission in samples annealed at higher temperatures were ascribed to Si impurities diffused from the substrate. Sharp reduction in mobility and surge in Hooge's parameter in sample annealed at 700 C implied high level of electron scattering due to large extrinsic Si impurities. Gradual rise in green-yellow emission and electron concentration as annealing temperature increased from 500 to 700 C were ascribed to the gradual formation of O vacancies.

Ke, Lin; Lai, Szu Cheng; Ye, Jian Dong; Kaixin, Vivian Lin; Chua, Soo Jin

2010-10-01

398

The effect of pressure on tricalcium silicate hydration at different temperatures and in the presence of retarding additives  

SciTech Connect

The hydration of tricalcium silicate (C{sub 3}S) is accelerated by pressure. However, the extent to which temperature and/or cement additives modify this effect is largely unknown. Time-resolved synchrotron powder diffraction has been used to study cement hydration as a function of pressure at different temperatures in the absence of additives, and at selected temperatures in the presence of retarding agents. The magnitudes of the apparent activation volumes for C{sub 3}S hydration increased with the addition of the retarders sucrose, maltodextrin, aminotri(methylenephosphonic acid) and an AMPS copolymer. Pressure was found to retard the formation of Jaffeite relative to the degree of C{sub 3}S hydration in high temperature experiments. For one cement slurry studied without additives, the apparent activation volume for C{sub 3}S hydration remained close to {approx} -28 cm{sup 3} mol{sup -1} over the range 25 to 60 C. For another slurry, there were possible signs of a decrease in magnitude at the lowest temperature examined.

Jupe, Andrew C.; Wilkinson, Angus P.; Funkhouser, Gary P. (Halliburton); (GIT)

2012-07-25

399

Study on the effects of different sulfur vaporization temperature on the properties of CuInS2 thin films  

NASA Astrophysics Data System (ADS)

CuInS2 (CIS) absorber thin films were prepared by sulfurization of In/Cu metallic stacked precursor. The precursor thin films were sulfurized using a commercial furnace system in the S2 (s) + Ar atmosphere at 425 C for 1 h. Effects of different S vapor temperature from 150 to 400 C on the structural, morphological, compositional and optical properties of CIS thin films were investigated. X-ray diffraction and Raman studies showed that the sulfurized thin films with S vaporization temperature below 300 C exhibited CIS tetragonal structure with secondary phases such as CuxSy, CuIn5S8, and InxSy. The sulfurized thin films with S vaporization temperature over 350 C showed a single CIS tetragonal structure. Compositional ratio of CIS thin films showed that Cu/In and S/(Cu + In) ratio in the CIS thin films with S vaporization temperature over 350 C were 1.0-1.2 and 0.9-1.1, respectively, while compositional ratio deviated from stoichiometry when the sulfurized thin films below S vaporization temperature of 350 C. Optical study showed that the band gap energy and the absorption coefficient of CIS thin films were estimated from 1.18 eV to 1.5 eV and over 104 cm-1, respectively.

Shin, Seung Wook; Han, Jun Hee; Lee, Jeong Yong; Park, Yeon Chan; Agawane, G. L.; Moholkar, A. V.; Gang, Myeong-Gil; Jeong, Chae Hwan; Kim, Jin Hyeok; Yun, Jae Ho

2013-04-01

400

Histopathological changes in gill, liver and kidney of neotropical fish Colossoma macropomum exposed to paraquat at different temperatures.  

PubMed

This work focused on the histological alterations in gill, liver and kidney of fish Colossoma macropomum exposed to different temperatures (18C, 29C, 35C) with 10mg/L of herbicide Paraquat (PQ), during 21 days. The fish exhibited histopathological changes in these tissues; the most important alteration in gills was telangiectasis. Liver showed debris accumulation inside cytoplasm hepatocytes, karyolysis, karyohesis and a decrease in the size of sinusoids. Hyperplasia of melanomacrophagic centers (MMC) and an increase in basophils were observed in kidney. The lesion inducing by PQ and the damage in tissue depended of temperature exposure fish. The severity of lesions clearly differed among organs with the liver showing the most extensive damages followed in order by the kidney and gills. In PQ/18C group it was observed the changes in the pattern of lesions, with kidney showing higher damage followed gills and liver. PMID:21787721

Salazar-Lugo, Raquel; Mata, Claunis; Oliveros, Aridays; Rojas, Luz Marina; Lemus, Mairin; Rojas-Villarroel, Evelin

2011-05-01

401

Electrical properties of carbon nanotubes synthesis by double furnace thermal-CVD technique at different temperatures on porous silicon template  

NASA Astrophysics Data System (ADS)

Multiwalled Carbon Nanotubes (MWCNs) were synthesized using double-furnace thermal chemical vapor deposition technique at 700 - 900 C on porous silicon nanostructure (PSiNs). Palm oil used as a carbon natural source, ferrocene as a catalyst and nitrogen gas as a carrier gas. The precursor were vaporized at 475 C carried by nitrogen gas which flow at constant rate 150 sccm/min. Carbon nanotubes characterized by using Raman Spectroscopy and field emission scanning electron microscopy (FESEM) to check its structure and crystallites before tested with I-V probe. Au contact used as a metal contact deposited on CNTs layer. Carbon nanotubes (CNTs) with uniform diameter were found grown on porous silicon for each temperature used. Based on micro-Raman spectroscopy result, the peak of carbon nanotubes (around 1 300 to 1 600 nm) was detected. The I-V characteristic of CNTs deposited had different profile when deposited at different temperature.

Husairi, F. S.; Zobir, S. A. M.; Rusop, M.; Abdullah, S.

2013-06-01

402

Basalt Weathering, Nutrient Uptake, And Carbon Release By An Exotic And A Native Arizona Grass Species Under Different Temperature Conditions  

NASA Astrophysics Data System (ADS)

During this past summer, the National Science Foundation funded a 10-week Research Experience for Undergraduates (REU) program Environmental and Earth Systems Research at Biosphere 2. This program provides undergraduates with an opportunity to conduct guided research in environmental and Earth systems science and has resulted in this work. Biosphere 2 allows for the exploration of complex questions in Earth sciences because of its large scale and the precise control allowed over many experimental elements. The goal of this study was to observe plant-mediated weathering of granular basalt under two temperature conditions. Two grass species were studied, one native to Arizona: Tanglehead, Heteropogan contortus, and one exotic to Arizona: Buffelgrass, Pennisetum ciliar. The grasses were grown in pots located in the Desert and the Savannah Biomes in the Biosphere 2 to take advantage of a 4 C temperature difference. Understanding differences in how native and invasive grasses weather soil and take up nutrients may explain the mechanism behind current invasion of Sonoran Desert by exotic species and help predict response of native and invasive vegetation to expected increase in temperatures. Each biome also contained three replicate control pots without vegetation, and mixtures of the two grass species to observe possible competition between the species. Three factors were compared in this study: 1. Temperature: the same species of grass under two different temperature conditions 2. Species: Native Arizonan species vs. a species exotic to Arizona 3. Temporal: How the grasses use resources differently as they grow Leachate samples were collected and analyzed for pH, electrical conductivity, total organic carbon, total nitrogen, inorganic carbon by high temperature combustion coupled with infrared gas analysis; F-, Cl-, Br-, NO3-, NO2-, SO42-, and PO43- by ion chromatography; and cations and metals by ICP-MS. The data trends indicate that plants enhanced basalt weathering. All of the leachate samples showed higher pH than the input water, and the pH was elevated in treatments that contained grass. This indicated that in the presence of vegetation there was more proton absorption. The trends in total nitrogen concentrations indicate a dependence on temperature; the same can be said of anion concentrations. Anion leaching is lower at higher temperatures possibly due to greater plant uptake. Both organic and inorganic carbon concentrations were found to be higher in grass treatments than in control treatments. Because both dissolved CO2 and soluble organic exudates encourage mineral dissolution, this could be causative of the weathering enhancements observed. Denudation of nutrient elements differed between plant species and between temperatures, possibly relating to plant uptake and secondary mineral formation. This study gives unique insight into plant-mineral interactions as a function of plant species and temperature that is essential for understanding Earth systems under changing climate.

Gallas, G.; Dontsova, K.; Chorover, J.; Hunt, E.; Ravi, S.

2010-12-01

403

Room temperature single-mode terahertz sources based on intracavity difference-frequency generation in quantum cascade lasers  

Microsoft Academic Search

We demonstrate room temperature single-mode THz emission at 4 THz based on intracavity difference-frequency generation from mid-infrared dual-wavelength quantum cascade lasers. An integrated dual-period distributed feedback grating is defined on the cap layer to purify both mid-infrared pumping wavelengths and in turn the THz spectra. Single mode operation of the pumping wavelengths results in a single-mode THz operation with a

Q. Y. Lu; N. Bandyopadhyay; S. Slivken; Y. Bai; M. Razeghi

2011-01-01

404

Thermoelectric Behavior of Sb and Al-Doped n Type Mg 2 Si Device Under Large Temperature Differences  

Microsoft Academic Search

The thermoelectric (TE) characteristics of Sb- and Al-doped n-type Mg2Si elemental devices fabricated using material produced from molten commercial doped polycrystalline Mg2Si were exa