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Sample records for absorption peaks centered

  1. Absorption, Creativity, Peak Experiences, Empathy, and Psychoticism.

    ERIC Educational Resources Information Center

    Mathes, Eugene W.; And Others

    Tellegen and Atkinson suggested that the trait of absorption may play a part in meditative skill, creativity, capacity for peak experiences, and empathy. Although the absorption-meditative skill relationship has been confirmed, other predictions have not been tested. Tellegen and Atkinson's Absorption Scale was completed by undergraduates in four…

  2. Microwave peak absorption frequency of liquid

    NASA Astrophysics Data System (ADS)

    Han, Guangze; Chen, Mingdong

    2008-09-01

    Microwave-assisted extraction is a new effective method which has practical applications in many fields. Microwave heating is one of its physical mechanisms, and it also has the characteristic of selectivity. When the applied microwave frequency equals a certain absorption frequency of the material (or specific component), the material will intensively absorb microwave energy. This is also known as resonant absorption, and the frequency is called the peak absorption frequency which depends on the physical structure of the material. In this work, dynamic hydrogen bond energy was included in molecular activation energy; with the liquid cell model, the expression of interaction energy between dipolar molecules was derived. The rotational relaxation time was gotten from the Eyring viscosity formula. Then based on the relationship between dielectric dissipation coefficient and relaxation time, the expression of microwave peak absorption frequency as a function of the material physical structure, rotational inertia and electrical dipole moment of molecules was established. These theoretical formulas were applied to water and benzene, and the calculated results agree fairly well with the experimental data. This work can not only deepen the study of the interaction between microwave and material, but also provide a possible guide for the experiment of microwave-assisted extraction.

  3. Determination of the total absorption peak in an electromagnetic calorimeter

    NASA Astrophysics Data System (ADS)

    Cheng, Jia-Hua; Wang, Zhe; Lebanowski, Logan; Lin, Guey-Lin; Chen, Shaomin

    2016-08-01

    A physically motivated function was developed to accurately determine the total absorption peak in an electromagnetic calorimeter and to overcome biases present in many commonly used methods. The function is the convolution of a detector resolution function with the sum of a delta function, which represents the complete absorption of energy, and a tail function, which describes the partial absorption of energy and depends on the detector materials and structures. Its performance was tested with the simulation of three typical cases. The accuracy of the extracted peak value, resolution, and peak area was improved by an order of magnitude on average, relative to the Crystal Ball function.

  4. Peak, multi-peak and broadband absorption in graphene-based one-dimensional photonic crystal

    NASA Astrophysics Data System (ADS)

    Miloua, R.; Kebbab, Z.; Chiker, F.; Khadraoui, M.; Sahraoui, K.; Bouzidi, A.; Medles, M.; Mathieu, C.; Benramdane, N.

    2014-11-01

    We theoretically investigate the possibility of enhancing light absorption in graphene-based one dimensional photonic crystal. We demonstrate that it is possible to achieve total light absorption at technologically important wavelengths using one-dimensional graphene-based photonic crystals. By means of the transfer matrix method, we investigate the effect of refractive indices and layer numbers on the optical response of the structure. We found that it is possible to achieve one peak, multi-peak or broadband, and complete optical absorption. As a result, the proposed photonic structures enable myriad potential applications such as photodetection, shielding and optical sensing.

  5. Automatic Locking of Laser Frequency to an Absorption Peak

    NASA Technical Reports Server (NTRS)

    Koch, Grady J.

    2006-01-01

    An electronic system adjusts the frequency of a tunable laser, eventually locking the frequency to a peak in the optical absorption spectrum of a gas (or of a Fabry-Perot cavity that has an absorption peak like that of a gas). This system was developed to enable precise locking of the frequency of a laser used in differential absorption LIDAR measurements of trace atmospheric gases. This system also has great commercial potential as a prototype of means for precise control of frequencies of lasers in future dense wavelength-division-multiplexing optical communications systems. The operation of this system is completely automatic: Unlike in the operation of some prior laser-frequency-locking systems, there is ordinarily no need for a human operator to adjust the frequency manually to an initial value close enough to the peak to enable automatic locking to take over. Instead, this system also automatically performs the initial adjustment. The system (see Figure 1) is based on a concept of (1) initially modulating the laser frequency to sweep it through a spectral range that includes the desired absorption peak, (2) determining the derivative of the absorption peak with respect to the laser frequency for use as an error signal, (3) identifying the desired frequency [at the very top (which is also the middle) of the peak] as the frequency where the derivative goes to zero, and (4) thereafter keeping the frequency within a locking range and adjusting the frequency as needed to keep the derivative (the error signal) as close as possible to zero. More specifically, the system utilizes the fact that in addition to a zero crossing at the top of the absorption peak, the error signal also closely approximates a straight line in the vicinity of the zero crossing (see Figure 2). This vicinity is the locking range because the linearity of the error signal in this range makes it useful as a source of feedback for a proportional + integral + derivative control scheme that

  6. 40. Peaks of Otter Visitor Center. The stone faced visitor ...

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

    40. Peaks of Otter Visitor Center. The stone faced visitor was completed in 1957 with a comfort station added in the mid-1960's. View is to the northwest. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  7. Varied absorption peaks of dual-band metamaterial absorber analysis by using reflection theory

    NASA Astrophysics Data System (ADS)

    Xiong, Han; Yu, Yan-Tao; Tang, Ming-Chun; Chen, Shi-Yong; Liu, Dan-Ping; Ou, Xiang; Zeng, Hao

    2016-03-01

    Cross-resonator metamaterial absorbers (MMA) have been widely investigated from microwave to optical frequencies. However, only part of the factors influencing the absorption properties were analyzed in previous works at the same time. In order to completely understand how the spacer thickness, dielectric parameter and incidence angle affect the absorption properties of the dual-band MMA, two sets of simulation were performed. It was found that with increasing incident angles, the low-frequency absorption peak showed a blue shift, while the high-frequency absorption peaks showed a red shift. However, with the increase in spacer thickness, both of the absorption peaks showed a red shift. By using the reflection theory expressions, the physical mechanism of the cross-resonator MMA was well explained. This method provides an effective way to analyze multi-band absorber in technology.

  8. Spectral calibration for infrared hyperspectral imaging Fourier transform spectrometer based on absorption peaks

    NASA Astrophysics Data System (ADS)

    Li, YaSheng; Chen, Yan; Liao, Ningfang; Lyu, Hang; He, Shufang; Wan, Lifang

    2015-08-01

    A new calibration method for infrared hyperspectral imaging Fourier transform spectrometer is presented. Two kinds of common materials as Polypropylene (PP) and Polyethylene Terephthalate (PET) films which have special absorption peaks in the infrared band were used in the calibration experiment. As the wavelengths at the sharp absorption peaks of the films are known, an infrared imaging spectrometer can be calibrated on spectra with two or three peaks. With high precision and stability, this method simplifies the calibration work. It is especially appropriate for the measuring condition with a lack of calibration equipment or with inconvenience to calibrate the multiple light sources outdoors.

  9. Unusual continuous dual absorption peaks in Ca-doped BiFeO3 nanostructures for broadened microwave absorption

    NASA Astrophysics Data System (ADS)

    Li, Zhong-Jun; Hou, Zhi-Ling; Song, Wei-Li; Liu, Xing-Da; Cao, Wen-Qiang; Shao, Xiao-Hong; Cao, Mao-Sheng

    2016-05-01

    Electromagnetic absorption materials have received increasing attention owing to their wide applications in aerospace, communication and the electronics industry, and multiferroic materials with both polarization and magnetic properties are considered promising ceramics for microwave absorption application. However, the insufficient absorption intensity coupled with the narrow effective absorption bandwidth has limited the development of high-performance multiferroic materials for practical microwave absorption. To address such issues, in the present work, we utilize interfacial engineering in BiFeO3 nanoparticles via Ca doping, with the purpose of tailoring the phase boundary. Upon Ca-substitution, the co-existence of both R3c and P4mm phases has been confirmed to massively enhance both dielectric and magnetic properties via manipulating the phase boundary and the destruction of the spiral spin structure. Unlike the commonly reported magnetic/dielectric hybrid microwave absorption composites, Bi0.95Ca0.05FeO3 has been found to deliver unusual continuous dual absorption peaks at a small thickness (1.56 mm), which has remarkably broadened the effective absorption bandwidth (8.7-12.1 GHz). The fundamental mechanisms based on the phase boundary engineering have been discussed, suggesting a novel platform for designing advanced multiferroic materials with wide applications.Electromagnetic absorption materials have received increasing attention owing to their wide applications in aerospace, communication and the electronics industry, and multiferroic materials with both polarization and magnetic properties are considered promising ceramics for microwave absorption application. However, the insufficient absorption intensity coupled with the narrow effective absorption bandwidth has limited the development of high-performance multiferroic materials for practical microwave absorption. To address such issues, in the present work, we utilize interfacial engineering in BiFeO3

  10. Unusual continuous dual absorption peaks in Ca-doped BiFeO3 nanostructures for broadened microwave absorption.

    PubMed

    Li, Zhong-Jun; Hou, Zhi-Ling; Song, Wei-Li; Liu, Xing-Da; Cao, Wen-Qiang; Shao, Xiao-Hong; Cao, Mao-Sheng

    2016-05-21

    Electromagnetic absorption materials have received increasing attention owing to their wide applications in aerospace, communication and the electronics industry, and multiferroic materials with both polarization and magnetic properties are considered promising ceramics for microwave absorption application. However, the insufficient absorption intensity coupled with the narrow effective absorption bandwidth has limited the development of high-performance multiferroic materials for practical microwave absorption. To address such issues, in the present work, we utilize interfacial engineering in BiFeO3 nanoparticles via Ca doping, with the purpose of tailoring the phase boundary. Upon Ca-substitution, the co-existence of both R3c and P4mm phases has been confirmed to massively enhance both dielectric and magnetic properties via manipulating the phase boundary and the destruction of the spiral spin structure. Unlike the commonly reported magnetic/dielectric hybrid microwave absorption composites, Bi0.95Ca0.05FeO3 has been found to deliver unusual continuous dual absorption peaks at a small thickness (1.56 mm), which has remarkably broadened the effective absorption bandwidth (8.7-12.1 GHz). The fundamental mechanisms based on the phase boundary engineering have been discussed, suggesting a novel platform for designing advanced multiferroic materials with wide applications. PMID:27143336

  11. Twin-peaks absorption spectra of excess electron in ionic liquids

    NASA Astrophysics Data System (ADS)

    Musat, Raluca M.; Kondoh, Takafumi; Yoshida, Yoichi; Takahashi, Kenji

    2014-07-01

    The solvated electron in room temperature ionic liquids (RTILs) has been the subject of several investigations and several reports exist on its nature and absorption spectrum. These studies concluded that the solvated electron exhibits an absorption spectrum peaking in the 1000-1400 nm region; a second absorption band peaking in the UV region has been assigned to the hole or dication radicals simultaneously formed in the system. Here we report on the fate of the excess electron in the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, P14+/NTf2- using nanosecond pulse radiolysis. Scavenging experiments allowed us to record and disentangle the complex spectrum measured in P14+/NTf2-. We identified a bi-component absorption spectrum, due to the solvated electron, the absorption maxima located at 1080 nm and around 300 nm, as predicted by previous ab-initio molecular dynamics simulations for the dry excess electron. We also measured the spectra using different ionic liquids and confirmed the same feature of two absorption peaks. The present results have important implications for the characterization of solvated electrons in ionic liquids and better understanding of their structure and reactivity.

  12. Observation of color center peaks in calcium fluoride.

    PubMed

    Aoki, T; Garvie, L A J; Rez, P

    2015-06-01

    Alkali halides such as calcium fluoride all have color center defects that absorb light in the visible region. Using a moncochromator equipped, aberration corrected, scanning transmission electron microscope (STEM) we recorded spectra showing the time evolution of the generation of F and H centers in calcium fluoride. The final stage of electron beam irradiation is the formation of metallic calcium nanoparticles. High resolution low loss spectra for the Vacuum Ultraviolet region were also recorded. PMID:25725200

  13. Analysis and Assessment of Peak Lightning Current Probabilities at the NASA Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Johnson, D. L.; Vaughan, W. W.

    1999-01-01

    This technical memorandum presents a summary by the Electromagnetics and Aerospace Environments Branch at the Marshall Space Flight Center of lightning characteristics and lightning criteria for the protection of aerospace vehicles. Probability estimates are included for certain lightning strikes (peak currents of 200, 100, and 50 kA) applicable to the National Aeronautics and Space Administration Space Shuttle at the Kennedy Space Center, Florida, during rollout, on-pad, and boost/launch phases. Results of an extensive literature search to compile information on this subject are presented in order to answer key questions posed by the Space Shuttle Program Office at the Johnson Space Center concerning peak lightning current probabilities if a vehicle is hit by a lightning cloud-to-ground stroke. Vehicle-triggered lightning probability estimates for the aforementioned peak currents are still being worked. Section 4.5, however, does provide some insight on estimating these same peaks.

  14. Asymmetric and symmetric absorption peaks observed in infrared spectra of CO2 adsorbed on TiO2 nanotubes

    NASA Astrophysics Data System (ADS)

    Yamakawa, Koichiro; Sato, Yoshinori; Fukutani, Katsuyuki

    2016-04-01

    Infrared spectra of CO2 physisorbed on titania nanotubes (TiNTs), predominantly in the anatase polymorph, were measured at 81 K. Asymmetric and symmetric absorption peaks due to the antisymmetric stretch vibration (ν3) of CO2 were observed at 2340 cm-1 and 2350 cm-1, respectively. On the basis of the exposure- and time-dependence of the spectrum, the 2340 cm-1 peak was attributed to CO2 at the defective sites related to subsurface O vacancies (Vos) while the 2350 cm-1 peak was assigned to that at the fivefold coordinated Ti4+ sites. It was found that the generalized Fano line shape was well fitted to the 2340 cm-1 peak. We also observed an absorption peak at 2372 cm-1, which was attributed to the combination band of ν3 and the external mode of CO2 at Ti4+.

  15. Thermoluminescence in pure LiF crystals: Glow peaks and their connection with color centers

    SciTech Connect

    Baldacchini, G.; Montereali, R. M.; Nichelatti, E.; Kalinov, V. S.; Voitovich, A. P.; Davidson, A. T.; Kozakiewicz, A. G.

    2008-09-15

    Nominally pure LiF crystals were irradiated with the same dose (0.85 10{sup 6} R) of gamma rays at ambient and low temperatures (-60 deg. C) and the resulting thermoluminescence (TL) is reported. Various optical and thermal treatments were applied in order to change the concentration of color centers (CCs). The effect of such treatments on the glow curves is observed. Knowing the coloration from optical transmission and photoluminescence measurements made on the same samples, we attribute many of the glow peaks (GPs) to the annealing of F center aggregates. For the present conditions of irradiation and dose, TL processes begin with decay of F{sub 3}{sup +} centers that display a GP at 164 deg. C. F{sub 3}(R) centers follow and are responsible for GPs at 193 and 228 deg. C. A GP at 263 deg. C is ascribed to F{sub 2} centers. Several peaks at temperatures in the range of 280-380 deg. C are associated with impurity perturbed F centers. A GP at 410 deg. C is associated with a complex of aggregated F and H centers. These attributions are accomplished by means of TL spectra, optical transmission spectra, and annealing procedures, and are critically discussed. The experimental data confirm the general trend of thermal stability of CCs, which decreases by moving from simple F centers to more complex ones, and the existence of exchange dynamics among CCs.

  16. A Peak Wind Probability Forecast Tool for Kennedy Space Center and Cape Canaveral Air Force Station

    NASA Technical Reports Server (NTRS)

    Crawford, Winifred; Roeder, William

    2008-01-01

    This conference abstract describes the development of a peak wind forecast tool to assist forecasters in determining the probability of violating launch commit criteria (LCC) at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) in east-central Florida. The peak winds are an important forecast element for both the Space Shuttle and Expendable Launch Vehicle (ELV) programs. The LCC define specific peak wind thresholds for each launch operation that cannot be exceeded in order to ensure the safety of the vehicle. The 45th Weather Squadron (45 WS) has found that peak winds are a challenging parameter to forecast, particularly in the cool season months of October through April. Based on the importance of forecasting peak winds, the 45 WS tasked the Applied Meteorology Unit (AMU) to develop a short-range peak-wind forecast tool to assist in forecasting LCC violatioas.The tool will include climatologies of the 5-minute mean end peak winds by month, hour, and direction, and probability distributions of the peak winds as a function of the 5-minute mean wind speeds.

  17. Center-to-center analysis of flow lineation and flow direction in Eocene welded ignimbrites, Twin Peaks, Idaho

    SciTech Connect

    Olsen, H.J. . Geology Dept.)

    1993-04-01

    Ignimbrites of the Eocene Twin Peaks caldera (Hardyman, 1982) in central Idaho's Challis Volcanic Field comprise both caldera-fill and outflow facies. The vents and mode of emplacement of these ignimbrites are problematic, because the Twin Peaks caldera has been strongly structurally disrupted, and lineations are sparse in the ignimbrites. Six oriented samples from three separate cooling units were studied using the Fry center-to-center method (Seaman and Williams, 1992) in order to determine flow lineation and flow direction of the ignimbrites inside the caldera. Flow lineation is defined in the plane parallel to flattened pumice and assumes that phenocryst are at maximum spacing in this plane. The flow lineation then coincides with the long axis of a center-to-center ellipse. Flow direction is defined in the plane perpendicular to flattening, which is inclined with respect to the flow plane and dips towards the source of flow. Four of five samples from the upper two cooling units near the thickest part of the caldera fill have well developed center-to-center strain ellipsoids producing flow lineations oriented N35W ([+-]7[degree]). The samples from the bottom cooling unit also has a well developed strain ellipsoid, but with a lineation oriented N80E. The difference in flow lineation suggests that the lowest cooling unit had a separate vent. Strain analysis of perpendicular sections are underway to establish the flow direction of the ignimbrites.

  18. Relationship between peak spatial-averaged specific absorption rate and peak temperature elevation in human head in frequency range of 1–30 GHz

    NASA Astrophysics Data System (ADS)

    Morimoto, Ryota; Laakso, Ilkka; De Santis, Valerio; Hirata, Akimasa

    2016-07-01

    This study investigates the relationship between the peak temperature elevation and the peak specific absorption rate (SAR) averaged over 10 g of tissue in human head models in the frequency range of 1–30 GHz. As a wave source, a half-wave dipole antenna resonant at the respective frequencies is located in the proximity of the pinna. The bioheat equation is used to evaluate the temperature elevation by employing the SAR, which is computed by electromagnetic analysis, as a heat source. The computed SAR is post-processed by calculating the peak spatial-averaged SAR with six averaging algorithms that consider different descriptions provided in international guidelines and standards, e.g. the number of tissues allowed in the averaging volume, different averaging shapes, and the consideration of the pinna. The computational results show that the SAR averaging algorithms excluding the pinna are essential when correlating the peak temperature elevation in the head excluding the pinna. In the averaging scheme considering an arbitrary shape, for better correlation, multiple tissues should be included in the averaging volume rather than a single tissue. For frequencies higher than 3–4 GHz, the correlation for peak temperature elevation in the head excluding the pinna is modest for the different algorithms. The 95th percentile value of the heating factor as well as the mean and median values derived here would be helpful for estimating the possible temperature elevation in the head.

  19. Absorption Peaks: α, β, γ and Their Covariance with Age and Hemoglobin in Human Blood Samples Using Photoacoustic Spectroscopy

    NASA Astrophysics Data System (ADS)

    González-Domínguez, J. L.; Hernández-Aguilar, C.; Domínguez-Pacheco, F. A.; Martínez-Ortiz, E.; Cruz-Orea, A.; Sánchez-Sinencio, F.

    2012-11-01

    This study reports the absorption peaks α, β, γ in the Soret band of photoacoustic (PA) signals and their covariance with age and hemoglobin in human blood samples through PA spectroscopy. Samples were taken randomly from a masculine population grouped in three categories according to age: infants, young adults, and senior adults. Samples were prepared with two drops of blood from a 0.5 mL insulin syringe with a needle gauge 31G over 5 mm circles of filter paper. It was observed that the PA signal, the amplitude as a function of the wavelength, has a behavior as that reported for human blood for the three absorption peaks α, β, γ. In particular, the ratio γ/ β is due to electronic transitions associated with charge-transfer interactions of iron orbitals with the ligand states. Through an evaluation of optical absorption peaks in blood samples and their covariance with age and hemoglobin concentration, a relationship was found for the ratio peaks γ/ β and γ/ α with such parameters. Specifically, a negative covariance in the Soret band of the ratio peaks γ/ β and γ/ α with respect to both age and hemoglobin was found. This showed a tendency in their behavior. Further experiments of different populations may corroborate these conclusions.

  20. Real-time bilinear rotation decoupling in absorptive mode J-spectroscopy: Detecting low-intensity metabolite peak close to high-intensity metabolite peak with convenience.

    PubMed

    Verma, Ajay; Baishya, Bikash

    2016-05-01

    "Pure shift" NMR spectra display singlet peak per chemical site. Thus, high resolution is offered at the cost of valuable J-coupling information. In the present work, real-time BIRD (BIlinear Rotation Decoupling) is applied to the absorptive-mode 2D J-spectroscopy to provide pure shift spectrum in the direct dimension and J-coupling information in the indirect dimension. Quite often in metabolomics, proton NMR spectra from complex bio-fluids display tremendous signal overlap. Although conventional J-spectroscopy in principle overcomes this problem by separating the multiplet information from chemical shift information, however, only magnitude mode of the experiment is practical, sacrificing much of the potential high resolution that could be achieved. Few J-spectroscopy methods have been reported so far that produce high-resolution pure shift spectrum along with J-coupling information for crowded spectral regions. In the present work, high-quality J-resolved spectrum from important metabolomic mixture such as tissue extract from rat cortex is demonstrated. Many low-intensity metabolite peaks which are obscured by the broad dispersive tails from high-intensity metabolite peaks in regular magnitude mode J-spectrum can be clearly identified in real-time BIRD J-resolved spectrum. The general practice of removing such spectral overlap is tedious and time-consuming as it involves repeated sample preparation to change the pH of the tissue extract sample and subsequent spectra recording. PMID:27026651

  1. Real-time bilinear rotation decoupling in absorptive mode J-spectroscopy: Detecting low-intensity metabolite peak close to high-intensity metabolite peak with convenience

    NASA Astrophysics Data System (ADS)

    Verma, Ajay; Baishya, Bikash

    2016-05-01

    "Pure shift" NMR spectra display singlet peak per chemical site. Thus, high resolution is offered at the cost of valuable J-coupling information. In the present work, real-time BIRD (BIlinear Rotation Decoupling) is applied to the absorptive-mode 2D J-spectroscopy to provide pure shift spectrum in the direct dimension and J-coupling information in the indirect dimension. Quite often in metabolomics, proton NMR spectra from complex bio-fluids display tremendous signal overlap. Although conventional J-spectroscopy in principle overcomes this problem by separating the multiplet information from chemical shift information, however, only magnitude mode of the experiment is practical, sacrificing much of the potential high resolution that could be achieved. Few J-spectroscopy methods have been reported so far that produce high-resolution pure shift spectrum along with J-coupling information for crowded spectral regions. In the present work, high-quality J-resolved spectrum from important metabolomic mixture such as tissue extract from rat cortex is demonstrated. Many low-intensity metabolite peaks which are obscured by the broad dispersive tails from high-intensity metabolite peaks in regular magnitude mode J-spectrum can be clearly identified in real-time BIRD J-resolved spectrum. The general practice of removing such spectral overlap is tedious and time-consuming as it involves repeated sample preparation to change the pH of the tissue extract sample and subsequent spectra recording.

  2. Forecasting Cool Season Daily Peak Winds at Kennedy Space Center and Cape Canaveral Air Force Station

    NASA Technical Reports Server (NTRS)

    Barrett, Joe, III; Short, David; Roeder, William

    2008-01-01

    The expected peak wind speed for the day is an important element in the daily 24-Hour and Weekly Planning Forecasts issued by the 45th Weather Squadron (45 WS) for planning operations at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The morning outlook for peak speeds also begins the warning decision process for gusts ^ 35 kt, ^ 50 kt, and ^ 60 kt from the surface to 300 ft. The 45 WS forecasters have indicated that peak wind speeds are a challenging parameter to forecast during the cool season (October-April). The 45 WS requested that the Applied Meteorology Unit (AMU) develop a tool to help them forecast the speed and timing of the daily peak and average wind, from the surface to 300 ft on KSC/CCAFS during the cool season. The tool must only use data available by 1200 UTC to support the issue time of the Planning Forecasts. Based on observations from the KSC/CCAFS wind tower network, surface observations from the Shuttle Landing Facility (SLF), and CCAFS upper-air soundings from the cool season months of October 2002 to February 2007, the AMU created multiple linear regression equations to predict the timing and speed of the daily peak wind speed, as well as the background average wind speed. Several possible predictors were evaluated, including persistence, the temperature inversion depth, strength, and wind speed at the top of the inversion, wind gust factor (ratio of peak wind speed to average wind speed), synoptic weather pattern, occurrence of precipitation at the SLF, and strongest wind in the lowest 3000 ft, 4000 ft, or 5000 ft. Six synoptic patterns were identified: 1) surface high near or over FL, 2) surface high north or east of FL, 3) surface high south or west of FL, 4) surface front approaching FL, 5) surface front across central FL, and 6) surface front across south FL. The following six predictors were selected: 1) inversion depth, 2) inversion strength, 3) wind gust factor, 4) synoptic weather pattern, 5) occurrence of

  3. AN OFF-CENTER DENSITY PEAK IN THE MILKY WAY'S DARK MATTER HALO?

    SciTech Connect

    Kuhlen, Michael; Guedes, Javiera; Pillepich, Annalisa; Madau, Piero; Mayer, Lucio

    2013-03-01

    We show that the position of the central dark matter (DM) density peak may be expected to differ from the dynamical center of the Galaxy by several hundred parsecs. In Eris, a high-resolution cosmological hydrodynamics simulation of a realistic Milky-Way-analog disk galaxy, this offset is 300-400 pc ({approx}3 gravitational softening lengths) after z = 1. In its dissipationless DM-only twin simulation ErisDark, as well as in the Via Lactea II and GHalo simulations, the offset remains below one softening length for most of its evolution. The growth of the DM offset coincides with a flattening of the central DM density profile in Eris inward of {approx}1 kpc, and the direction from the dynamical center to the point of maximum DM density is correlated with the orientation of the stellar bar, suggesting a bar-halo interaction as a possible explanation. A DM density offset of several hundred parsecs greatly affects expectations of the DM annihilation signals from the Galactic center. It may also support a DM annihilation interpretation of recent reports by Weniger and Su and Finkbeiner of highly significant 130 GeV gamma-ray line emission from a region 1. Degree-Sign 5 ({approx}200 pc projected) away from Sgr A* in the Galactic plane.

  4. Application of wavelet transforms to determine peak shape parameters for interference detection in graphite-furnace atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Sadler, D. A.; Littlejohn, D.; Boulo, P. R.; Soraghan, J. S.

    1998-08-01

    A procedure to quantify the shape of the absorbance-time profile, obtained during graphite furnace atomic absorption spectrometry, has been used to detect interference effects caused by the presence of a concomitant salt. The quantification of the absorption profile is achieved through the use of the Lipschitz regularity, α0, obtained from the wavelet transform of the absorbance-time profile. The temporal position of certain features and their associated values of α0 provide a unique description of the shape of the absorbance-time profile. Changes to the position or values of α0 between standard and sample atomizations may be indicative of uncorrected interference effects. A weak, but linear, dependence was found of the value of α0 upon the analyte concentration for Cr and Cu. The ability of the Lipschitz regularity to detect interference effects was illustrated for Pb, Se and Cu. For Pb, the lowest concentration of NaCl added, 0.005% m/v, changed both the values of α0 and the peak height absorbance. For Se, no change in the peak height and peak area absorbance signals was detected up to a NaCl concentration of 0.25% m/v. The values of the associated Lipschitz regularities were found to be invariant to NaCl concentration up to this value. For Cu, a concentration of 0.05% m/v NaCl reduced the peak height and peak area absorbance signals by approximately 25% and significantly altered the values of α0.

  5. Tiny peaks vs mega backgrounds: a general spectroscopic method with applications in resonant Raman scattering and atmospheric absorptions.

    PubMed

    Auguié, Baptiste; Reigue, Antoine; Le Ru, Eric C; Etchegoin, Pablo G

    2012-09-18

    A simple method using standard spectrometers with charge-coupled device (CCD) detectors is described to routinely measure background-corrected spectra in situations where the signal is composed of weak spectral features (such as Raman peaks or absorption lines) engulfed in a much stronger (by as much as ∼10(5)) broad background. The principle of the method is to subtract the dominant fixed-structure noise and obtain a shot-noise limited spectrum. The final noise level can therefore be reduced as desired by sufficient integration time. The method requires multiple shifts of the diffraction gratings to extract the pixel-dependent noise structure, which is then used as a flat-field correction. An original peak-retrieval procedure is proposed, demonstrating accurate determination of peak lineshapes and linewidths and robustness on practical examples where conventional methods would not be applicable. Examples are discussed to illustrate the potential of the technique to perform routine resonant Raman measurements of fluorescent dyes with high quantum yield, using conventional Raman systems. The method can equally be applied to other situations where small features are masked by a broad overwhelming background. An explicit example is given with the measurement of weak absorption lines in atmospheric gases. PMID:22894881

  6. Gravity and thermal models for the twin peaks silicic volcanic center, Southwestern Utah

    SciTech Connect

    Carrier, D.L.; Chapman, D.S.

    1981-11-10

    Gravity, heat flow, and surface geology observations have been used as constraints for a thermal model of a late Tertiary silicic volcanic center at Twin Peaks, Utah. Silicic Volcanism began in the area with the extrusion of the Coyote Hills rhyolite 2.74 +- 0.1 m.y. ago, followed by the Cudahy Mine obsidian, felsite, and volcanoclastics, and finally by a complex sequence of domes and flows that lasted until 2.3 +- 0.1 m.y. ago. Basalt sequence span the time 2.5 to 0.9 m.y. Terrain-corrected Bouguer gravity anomalies at Twin Peaks are shaped by three features of varying characteristic dimensions: (1) a major north-northeast trending --30 mGal gravity trough roughly 40 km wide caused by a thick sequence of Cenozoic sediments in the Black Rock Desert Valley, (2) a local roughly circular -7 mGal gravity low, 26 km across, probably related to an intrusive body in the basement, and (3) a series of narrow positive anomalies up to + 10 mGal produced by the major Twin Peaks volcanic domes. The intrusive bodies have been modeled as three-dimensional vertical cylinders; the total volume of intrusive material is estimated to be about 500 km/sup 3/. Simple models, assuming conductive heat transfer and using geometrical constraints from the gravity results, predict that a negligible thermal anomaly should exist 1 m.y. after emplacement of the intrusion. This prediction is consistent with an average heat flow of 96 mW m/sup -2/ for the area, not significantly different from eastern Basin and Range values elsewhere. Magmatic longevity of this system 2.7 to 2.3 m.y. for silicic volcanism of 2.5 to 0.9 m.y. for basaltic volcanism, does not seem to prolong the cooling of the system substantially beyond that predicted by conductive cooling.

  7. Energy peak: Back to the Galactic Center GeV gamma-ray excess

    NASA Astrophysics Data System (ADS)

    Kim, Doojin; Park, Jong-Chul

    2016-03-01

    We propose a novel mechanism enabling us to have a continuum bump as a signature of gamma-ray excess in indirect detection experiments of dark matter (DM), postulating a generic dark sector having (at least) two DM candidates. With the assumption of non-zero mass gap between the two DM candidates, the heavier one directly communicates to the partner of the lighter one. Such a partner then decays into a lighter DM particle along with an "axion-like" particle (ALP) or dark "pion", which subsequently decays into a pair of photons, via a more-than-one step cascade decay process. Since the cascade is initiated by the dark partner obtaining a non-trivial fixed boost factor, a continuum γ-ray energy spectrum naturally arises even with a particle directly decaying into two photons. We apply the main idea to the energy spectrum of the GeV γ-rays from around the Galactic Center (GC), and find that the relevant observational data is well-reproduced by the theory expectation predicted by the proposed mechanism. Remarkably, the relevant energy spectrum has a robust peak at half the mass of the ALP or dark pion, as opposed to popular DM models directly annihilating to Standard Model particles where physical interpretations of the energy peak are not manifest. Our data analysis reports substantially improved fits, compared to those annihilating DM models, and ∼ 900 MeV mass of the ALP or dark pion.

  8. The Silver Peak Volcanic Center: Shoshonitic Volcanism in the Walker Lane, Western Nevada

    NASA Astrophysics Data System (ADS)

    Robinson, P. T.; Zhou, M.; Li, J.; Chen, L.; Ma, C.; Gao, J.

    2012-12-01

    Shoshonitic and high-K volcanism is widespread in the Sierra Nevada and western Nevada. The Silver Peak center, located in the Walker Lane, just east of the White Mountains, lies within the Silver Peak detachment. It consists of a subcircular volcanic complex about 15 km in diameter, with a central caldera. Volcanic activity spanned a period of 1myr from 6.0±0.5 to 4.8±0.6 Ma. The lavas range from trachybasalt to rhyolite and plot in the shoshonite field on the SiO2-K2O diagram. Oxide trends indicate relatively continuous fractionation of a parental basaltic magma. Fractionation took place in a subvolcanic magma chamber, which was periodically injected with new batches of basalt, leading to two major explosive events and resetting the fractionation processes. The first event, which erupted voluminous rhyolite ashflows, resulted in an elliptical caldera 12 by 9 km; the second produced highly feldspar-phyric trachyandesite ashflows and lavas. The most mafic lava is a trachybasalt with about 49 wt% SiO2, 7.5 wt% MgO and 2.5 wt% K2O, which contains olivine phenocrysts of Fo85. Chondrite-normalized REE patterns of the lavas show flat HREE, strong enrichment in LREE (LaN/SmN =3.5-7.7; aver. = 4.7) and variable negative Eu anomalies ranging from .21-.85. In-situ 87Sr/86Sr compositions of plagioclase grains are quite uniform, mostly between 0.7060 and 0.7070, similar to the whole-rock values (0.7061) and indicating little if any crustal contamination. We suggest that the parental magma was derived from a metasomatised mantle source by small degrees of partial melting. It was mixed periodically with new pulses of mafic magma and underwent fractional crystallization to produce the observed range of compositions. . Melting was probably triggered by transtensional deformation in the Walker Lane.

  9. Experimental phasing using zinc and sulfur anomalous signals measured at the zinc absorption peak.

    PubMed

    Lee, Sangmin; Kim, Min-Kyu; Ji, Chang-Jun; Lee, Jin-Won; Cha, Sun-Shin

    2013-10-01

    Iron is an essential transition metal required for bacterial growth and survival. Excess free iron can lead to the generation of reactive oxygen species that can cause severe damage to cellular functions. Cells have developed iron-sensing regulators to maintain iron homeostasis at the transcription level. The ferric uptake regulator (Fur) is an iron-responsive regulator that controls the expression of genes involved in iron homeostasis, bacterial virulence, stress resistance, and redox metabolism. Here, we report the expression, purification, crystallization, and phasing of the apo-form of Bacillus subtilis Fur (BsFur) in the absence of regulatory metal ions. Crystals were obtained by microbatch crystallization method at 295 K and diffraction data at a resolution of 2.6 Å was collected at the zinc peak wavelength (λ=1.2823 Å). Experimental phasing identified the positions of one zinc atom and four sulfur atoms of cysteine residues coordinating the zinc atom, indicating that the data contained a meaningful anomalous scattering originating from the ordered zinc-coordinating sulfur atoms, in spite of the small anomalous signals of sulfur atoms at the examined wavelength. PMID:24173644

  10. Glass Composition-Dependent Silicate Absorption Peaks in FTIR Spectroscopy: Implications for Measuring Sample Thickness and Molecular H2O

    NASA Astrophysics Data System (ADS)

    McIntosh, I. M.; Nichols, A. R.; Schipper, C. I.; Stewart, R. B.

    2015-12-01

    Fourier-transform infrared spectroscopy (FTIR) is often used to measure the H2O and CO2 contents of volcanic glasses. A key advantage of FTIR over other analytical techniques is that it can reveal not only total H2O concentration but also H2O speciation, i.e. how much H2O is present as molecular H2O (H2Om) and how much as hydroxyl groups (OH) bound to the silicate network. This H2O speciation data can be used to investigate cooling rate and glass transition temperature of volcanic glasses, and to interpret H2O contents of pyroclasts affected by partial bubble resorption during cooling or secondary hydration after deposition. FTIR in transmitted light requires sample wafers polished on both sides of known thickness. Thickness is commonly measured using a micrometer but this may damage fragile samples and in samples with non-uniform thickness, e.g. vesicular samples, it is difficult to position at the exact location of FTIR analysis. Furthermore, in FTIR images or maps of such samples it is impractical to determine the thickness across the whole of the analysed area, resulting either in only a selection of the collected data being processed quantitatively and the rest being unused, or results being presented in terms of absorbance, which does not account for variations in thickness.It is known that FTIR spectra contain absorption peaks related to the glass aluminosilicate network at wavenumbers of ~2000, ~1830 and ~1600 cm-1 [1]. These have been shown to be proportional to sample thickness at the analysis location for one obsidian composition with up to 0.66 wt% H2O [2]. We test whether this calibration can be applied more widely by analysing a range of synthetic and natural glasses (andesitic to rhyolitic) to examine how the position and relative intensities of the different silicate absorption peaks vary with composition and H2O content. Our data show that even minor differences in composition necessitate a unique calibration. Furthermore, importantly we show how

  11. Developing a Peak Wind Probability Forecast Tool for Kennedy Space Center and Cape Canaveral Air Force Station

    NASA Technical Reports Server (NTRS)

    Lambert, WInifred; Roeder, William

    2007-01-01

    This conference presentation describes the development of a peak wind forecast tool to assist forecasters in determining the probability of violating launch commit criteria (LCC) at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS) in east-central Florida. The peak winds are an important forecast element for both the Space Shuttle and Expendable Launch Vehicle (ELV) programs. The LCC define specific peak wind thresholds for each launch operation that cannot be exceeded in order to ensure the safety of the vehicle. The 45th Weather Squadron (45 WS) has found that peak winds are a challenging parameter to forecast, particularly in the cool season months of October through April. Based on the importance of forecasting peak winds, the 45 WS tasked the Applied Meteorology Unit (AMU) to develop a short-range peak-wind forecast tool to assist in forecasting LCC violations. The tool will include climatologies of the 5-minute mean and peak winds by month, hour, and direction, and probability distributions of the peak winds as a function of the 5-minute mean wind speeds.

  12. The spectral variability of the GHZ-Peaked spectrum radio source PKS 1718-649 and a comparison of absorption models

    SciTech Connect

    Tingay, S. J.; Macquart, J.-P.; Wayth, R. B.; Trott, C. M.; Emrich, D.; Collier, J. D.; Wong, G. F.; Rees, G.; Stevens, J.; Carretti, E.; Callingham, J. R.; Gaensler, B. M.; McKinley, B.; Briggs, F.; Bernardi, G.; Bowman, J. D.; Cappallo, R. J.; Corey, B. E.; Deshpande, A. A.; Goeke, R.; and others

    2015-02-01

    Using the new wideband capabilities of the ATCA, we obtain spectra for PKS 1718-649, a well-known gigahertz-peaked spectrum radio source. The observations, between approximately 1 and 10 GHz over 3 epochs spanning approximately 21 months, reveal variability both above the spectral peak at ∼3 GHz and below the peak. The combination of the low- and high-frequency variability cannot be easily explained using a single absorption mechanism, such as free–free absorption or synchrotron self-absorption. We find that the PKS 1718-649 spectrum and its variability are best explained by variations in the free–free optical depth on our line of sight to the radio source at low frequencies (below the spectral peak) and the adiabatic expansion of the radio source itself at high frequencies (above the spectral peak). The optical depth variations are found to be plausible when X-ray continuum absorption variability seen in samples of active galactic nuclei is considered. We find that the cause of the peaked spectrum in PKS 1718-649 is most likely due to free–free absorption. In agreement with previous studies, we find that the spectrum at each epoch of observation is best fit by a free–free absorption model characterized by a power-law distribution of free–free absorbing clouds. This agreement is extended to frequencies below the 1 GHz lower limit of the ATCA by considering new observations with Parkes at 725 MHz and 199 MHz observations with the newly operational Murchison Widefield Array. These lower frequency observations argue against families of absorption models (both free–free and synchrotron self-absorption) that are based on simple homogenous structures.

  13. Formation and conversion of defect centers in low water peak single mode optical fiber induced by gamma rays irradiation

    SciTech Connect

    Wen, J. X.; Luo, W. Y.; Xiao, Z. Y.; Wang, T. Y.; Chen, Z. Y.; Zeng, X. L.

    2010-02-15

    The formation and conversion processes of defect centers in low water peak single mode optical (LWPSM) fiber irradiated with gamma rays were investigated at room temperature using electron spin resonance. Germanium electron center (GEC) and self-trapped hole center (STH) occur when the fibers are irradiated with 1 and 5 kGy cumulative doses, respectively. With the increase in irradiation doses, the GEC defect centers disappear, and new defect centers such as E{sup '} centers (Si and Ge) and nonbridge oxygen hole centers (NBOHCs) generate. The generation of GEC and STH is attributed to the electron transfer, which is completely balanced. This is the main reason that radiation-induced attenuation (RIA) of the LWPSM fiber is only 10 dB/km at communication window. The new defect centers come from the conversion of GEC and STH to E{sup '} centers and NBOHC, and the conversion processes cause bond cleavage, which is the root cause that the RIA of the LWPSM fiber significantly increases up to 180 dB/km at working window. Furthermore, the concentration of new defect centers is saturated easily even by increasing cumulative doses.

  14. Dietary supplementation with sodium bicarbonate improves calcium absorption and eggshell quality of laying hens during peak production.

    PubMed

    Jiang, M J; Zhao, J P; Jiao, H C; Wang, X J; Zhang, Q; Lin, H

    2015-01-01

    The advantage of supplemental sodium bicarbonate (NaHCO3) on eggshell quality in laying hens changes with age. Besides increasing calcium (Ca) secretion in the eggshell gland, it may improve Ca absorption in the intestine or kidney. Hy-Line Brown layers (n = 384), 25 weeks of age, were allocated to two treatment groups in two experiments, each of which included 4 replicates of 24 hens. Hens were fed a basal diet (control) or the basal diet containing 3 g NaHCO3 g/kg for 50 or 20 weeks in Experiment 1 or 2, respectively. A 24-h continuous lighting regimen was used to allow hens to consume the dietary supplements during the period of active eggshell formation. In Experiment 1, particularly from 25 to 50 weeks of age, and in Experiment 2, NaHCO3 supplementation favoured hen-d egg production at the expense of lower egg weight. The increased eggshell thickness should have nothing to do with the additional eggshell formation, because of the unchanged egg mass and daily eggshell calcification. At 35 weeks of age in both experiments, NaHCO3 supplementation increased duodenal expression of calbindin-d28k (CaBP-D28k) protein, contributing to higher Ca retention and balance. From 50 to 75 weeks of age in Experiment 1, the hens had little response to NaHCO3 supplementation and showed a negative trend on eggshell thickness and strength. It is concluded that dietary supplementation with 3 g NaHCO3 g/kg improves Ca absorption and eggshell quality of laying hens during the peak but not late production period, with the introduction of continuous lighting. PMID:26569471

  15. An X-ray absorption method for the identification of calcium phosphate species using peak height ratios

    NASA Astrophysics Data System (ADS)

    Oxmann, J. F.

    2013-11-01

    X-ray absorption near edge structure (XANES) studies on calcium phosphate species (Ca-P) deal with marginal differences among subtle spectral features despite a hitherto missing systematic breakdown of these differences. Related fingerprinting approaches depend therefore on spectral libraries that are not validated against each other, incomplete and scattered among publications. This study compiled a comprehensive spectral library from published reference compound libraries in order to establish more clear-cut criteria for Ca-P determination by distinctive phosphorus K-edge XANES features. A specifically developed normalization method identified diagnostic spectral features within the compiled library, e.g. by uniform calculation of ratios between white-line and secondary peak heights. Post-processing of the spectra (n = 81) verified distinguishability among most but not all phases, which included hydroxylapatite (HAP), poorly crystalline HAP, amorphous HAP, fluorapatite, carbonate fluorapatite (CFAP), carbonate hydroxylapatite, β-tricalcium phosphate, octacalcium phosphate (OCP), brushite, monetite, monocalcium phosphate, amorphous calcium phosphate (ACP), anapaite, herderite, scholzite, messelite, whiteite and P on CaCO3. Particularly, peak height ratios significantly improved analyte specificity, e.g. by supplementary breakdown into OCP and ACP. The spectral analysis also revealed Ca-P standards that were rarely investigated or inappropriately synthesized, and thus provides a basis for standard selection and synthesis. The developed method and resulting breakdown by species were subsequently tested on Ca-P spectra from studies on bone and sediment. The test indicated that bone material likely comprises only poorly crystalline apatite, which implies direct nucleation of apatite in bone. This biological apatite formation is likely opposed to that of sedimentary apatite, which apparently forms by successive crystallization. Application of the method to

  16. Technical Note: An X-ray absorption method for the identification of calcium phosphate species using peak-height ratios

    NASA Astrophysics Data System (ADS)

    Oxmann, J. F.

    2014-04-01

    X-ray absorption near edge structure (XANES) studies on calcium phosphate species (Ca-P) deal with marginal differences among subtle spectral features despite a hitherto missing systematic breakdown of these differences. Related fingerprinting approaches depend, therefore, on spectral libraries that are not validated against each other, incomplete and scattered among publications. This study compiled a comprehensive spectral library from published reference compound libraries in order to establish more clear-cut criteria for Ca-P determination by distinctive phosphorus K-edge XANES features. A specifically developed normalization method identified diagnostic spectral features in the compiled library, e.g. by uniform calculation of ratios between white-line and secondary peak heights. Post-processing of the spectra (n = 81) verified distinguishability among most but not all phases, which included hydroxylapatite (HAP), poorly crystalline HAP, amorphous HAP, fluorapatite, carbonate fluorapatite (CFAP), carbonate hydroxylapatite, β-tricalcium phosphate, octacalcium phosphate (OCP), brushite, monetite, monocalcium phosphate, amorphous calcium phosphate (ACP), anapaite, herderite, scholzite, messelite, whiteite and P on CaCO3. Particularly, peak-height ratios significantly improved analyte specificity, e.g. by supplementary breakdown into OCP and ACP. The spectral analysis also revealed Ca-P standards that were rarely investigated or inappropriately synthesized, and thus provides a basis for standard selection and synthesis. The method developed and resulting breakdown by species were subsequently tested on Ca-P spectra from studies on bone and sediment. The test indicated that bone material likely comprises only poorly crystalline apatite, which confirms direct nucleation of apatite in bone. This biological apatite formation is likely opposed to that of sedimentary apatite, which apparently forms by both direct nucleation and successive crystallization. Application of

  17. Effects of Fusion Zone Size and Failure Mode on Peak Load and Energy Absorption of Advanced High Strength Steel Spot Welds under Lap Shear Loading Conditions

    SciTech Connect

    Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2008-06-01

    This paper examines the effects of fusion zone size on failure modes, static strength and energy absorption of resistance spot welds (RSW) of advanced high strength steels (AHSS) under lap shear loading condition. DP800 and TRIP800 spot welds are considered. The main failure modes for spot welds are nugget pullout and interfacial fracture. Partial interfacial fracture is also observed. Static weld strength tests using lap shear samples were performed on the joint populations with various fusion zone sizes. The resulted peak load and energy absorption levels associated with each failure mode were studied for all the weld populations using statistical data analysis tools. The results in this study show that AHSS spot welds with conventionally required fusion zone size of can not produce nugget pullout mode for both the DP800 and TRIP800 welds under lap shear loading. Moreover, failure mode has strong influence on weld peak load and energy absorption for all the DP800 welds and the TRIP800 small welds: welds failed in pullout mode have statistically higher strength and energy absorption than those failed in interfacial fracture mode. For TRIP800 welds above the critical fusion zone level, the influence of weld failure modes on peak load and energy absorption diminishes. Scatter plots of peak load and energy absorption versus weld fusion zone size were then constructed, and the results indicate that fusion zone size is the most critical factor in weld quality in terms of peak load and energy absorption for both DP800 and TRIP800 spot welds.

  18. Identification of B-K near edge x-ray absorption fine structure peaks of boron nitride thin films prepared by sputtering deposition

    SciTech Connect

    Niibe, Masahito; Miyamoto, Kazuyoshi; Mitamura, Tohru; Mochiji, Kozo

    2010-09-15

    Four {pi}{sup *} resonance peaks were observed in the B-K near edge x-ray absorption fine structure spectra of boron nitride thin films prepared by magnetron sputtering. In the past, these peaks have been explained as the K-absorption of boron atoms, which are present in environment containing nitrogen vacancies, the number of which is 1-3 corresponding to the three peaks at higher photon energy. However, the authors found that there was a strong correlation between the intensities of these three peaks and that of O-K absorption after wide range scanning and simultaneous measurement of nitrogen and oxygen K-absorptions of the BN films. Therefore, the authors conclude that these three peaks at the higher energy side correspond to boron atoms bound to one-to-three oxygen atoms instead of three nitrogen atoms surrounding the boron atom in the h-BN structure. The result of the first-principles calculation with a simple cluster model supported the validity of this explanation.

  19. The {ital b} Distribution and the Velocity Structure of Absorption Peaks in the Ly{alpha} Forest

    SciTech Connect

    Hui, L.

    1999-06-01

    A theory is developed that relates the observed {ital b} parameter of a Ly{alpha} absorption line to the velocity curvature of the corresponding peak in the optical depth fluctuation. Its relation to the traditional interpretation of {ital b} as the thermal broadening width is discussed. It is demonstrated that, independent of the details of the cosmological model, the differential {ital b} distribution has a high-{ital b} asymptote of dN/db{proportional_to}b{sup {minus}m}, where m{ge}5, when we make the reasonable assumption that low-curvature fluctuations are statistically favored over high-curvature ones. There in general always exist lines much broader than the thermal width. We develop a linear perturbative analysis of the optical depth fluctuation, which yields a single-parameter prediction for the full {ital b} distribution. In addition to exhibiting the high-velocity tail, it qualitatively explains the observed sharp low-{ital b} cutoff{emdash}a simple reflection of the fact that high-curvature fluctuations are relatively rare. Although the existence of the high-{ital b} asymptote, which is independent of the validity of the linear expansion, is consistent with the observed {ital b} distribution, a detailed comparison of the linear prediction with six observational data sets indicates that higher order corrections are not negligible. The perturbative analysis nonetheless offers valuable insights into the dependence of the {ital b} distribution on cosmological parameters such as {Omega} and the power spectrum. A key parameter is the effective smoothing scale of the optical depth fluctuation, which is in turn determined by three scales: the thermal broadening width, the baryon smoothing scale (approximately the Jeans scale), and the observation/simulation resolution. The first two are determined by reionization history, but are comparable in general, whereas the third varies by about an order of magnitude in current hydrodynamic simulations. Studies with non

  20. Performance characteristics of single effect lithium bromide/ water absorption chiller for small data centers

    NASA Astrophysics Data System (ADS)

    Mysore, Abhishek Arun Babu

    A medium data center consists of servers performing operations such as file sharing, collaboration and email. There are a large number of small and medium data centers across the world which consume more energy and are less efficient when compared to large data center facilities of companies such as GOOGLE, APPLE and FACEBOOK. Such companies are making their data center facilities more environmental friendly by employing renewable energy solutions such as wind and solar to power the data center or in data center cooling. This not only reduces the carbon footprint significantly but also decreases the costs incurred over a period of time. Cooling of data center play a vital role in proper functioning of the servers. It is found that cooling consumes about 50% of the total power consumed by the data center. Traditional method of cooling includes the use of mechanical compression chillers which consume lot of power and is not desirable. In order to eliminate the use of mechanical compressor chillers renewable energy resources such as solar and wind should be employed. One such technology is solar thermal cooling by means of absorption chiller which is powered by solar energy. The absorption chiller unit can be coupled with either flat plate or evacuated tube collectors in order to achieve the required inlet temperature for the generator of the absorption chiller unit. In this study a modular data center is considered having a cooling load requirement of 23kw. The performance characteristics of a single stage Lithium Bromide/ water refrigeration is presented in this study considering the cooling load of 23kw. Performance characteristics of each of the 4 heat exchangers within the unit is discussed which helps in customizing the unit according to the users' specific needs. This analysis helps in studying the importance of different properties such as the effect of inlet temperatures of hot water for generator, inlet temperatures of cooling water for absorber and

  1. Wavelength Locking to CO2 Absorption Line-Center for 2-Micron Pulsed IPDA Lidar Application

    NASA Technical Reports Server (NTRS)

    Refaat, Tamer F.; Petros, Mulugeta; Antill, Charles W.; Singh, Upendra N.; Yu, Jirong

    2016-01-01

    An airborne 2-micron triple-pulse integrated path differential absorption (IPDA) lidar is currently under development at NASA Langley Research Center (LaRC). This IPDA lidar system targets both atmospheric carbon dioxide (CO2) and water vapor (H2O) column measurements. Independent wavelength control of each of the transmitted laser pulses is a key feature for the success of this instrument. The wavelength control unit provides switching, tuning and locking for each pulse in reference to a 2-micron CW (Continuous Wave) laser source locked to CO2 line-center. Targeting the CO2 R30 line center, at 2050.967 nanometers, a wavelength locking unit has been integrated using semiconductor laser diode. The CO2 center-line locking unit includes a laser diode current driver, temperature controller, center-line locking controller and CO2 absorption cell. This paper presents the CO2 center-line locking unit architecture, characterization procedure and results. Assessment of wavelength jitter on the IPDA measurement error will also be addressed by comparison to the system design.

  2. A search for subpicosecond absorption components in photosystem II reaction centers

    NASA Astrophysics Data System (ADS)

    McCauley, S. W.; Baronavski, A. P.; Rice, Jane K.; Ghirardi, M. L.; Mattoo, A. K.

    1992-10-01

    The transient absorption kinetics of spinach photosystem II reaction centers were measured at 672 nm (detection bandwidth ≈ 11 nm) following excitation at 310 nm. A temporal resolution of ≈ 50 fs was used which is three times higher resolution than the current literature value. We observed a very fast absorption decrease with a rise time of 150 ± 15 fs followed by a 13 ± 4 ps recovery. The kinetics of the recovery step did not reveal a 3 ps component, however, a slight break in the data suggests a more complicated fit may explain the data as well or better. Based on a comparison of the rise time reported here and those reported by Durrant, the relaxation from S n to S 1 occurs very rapidly, within the 150 fs initial absorption decrease.

  3. Cavity-Enhanced Room-Temperature Magnetometry Using Absorption by Nitrogen-Vacancy Centers in Diamond

    NASA Astrophysics Data System (ADS)

    Jensen, K.; Leefer, N.; Jarmola, A.; Dumeige, Y.; Acosta, V. M.; Kehayias, P.; Patton, B.; Budker, D.

    2014-04-01

    We demonstrate a cavity-enhanced room-temperature magnetic field sensor based on nitrogen-vacancy centers in diamond. Magnetic resonance is detected using absorption of light resonant with the 1042 nm spin-singlet transition. The diamond is placed in an external optical cavity to enhance the absorption, and significant absorption is observed even at room temperature. We demonstrate a magnetic field sensitivity of 2.5 nT/√Hz , and project a photon shot-noise-limited sensitivity of 70 pT/√Hz for a few mW of infrared light, and a quantum projection-noise-limited sensitivity of 250 fT/√Hz for the sensing volume of ˜90 μm ×90 μm×200 μm.

  4. Tool for Forecasting Cool-Season Peak Winds Across Kennedy Space Center and Cape Canaveral Air Force Station

    NASA Technical Reports Server (NTRS)

    Barrett, Joe H., III; Roeder, William P.

    2010-01-01

    The expected peak wind speed for the day is an important element in the daily morning forecast for ground and space launch operations at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The 45th Weather Squadron (45 WS) must issue forecast advisories for KSC/CCAFS when they expect peak gusts for >= 25, >= 35, and >= 50 kt thresholds at any level from the surface to 300 ft. In Phase I of this task, the 45 WS tasked the Applied Meteorology Unit (AMU) to develop a cool-season (October - April) tool to help forecast the non-convective peak wind from the surface to 300 ft at KSC/CCAFS. During the warm season, these wind speeds are rarely exceeded except during convective winds or under the influence of tropical cyclones, for which other techniques are already in use. The tool used single and multiple linear regression equations to predict the peak wind from the morning sounding. The forecaster manually entered several observed sounding parameters into a Microsoft Excel graphical user interface (GUI), and then the tool displayed the forecast peak wind speed, average wind speed at the time of the peak wind, the timing of the peak wind and the probability the peak wind will meet or exceed 35, 50 and 60 kt. The 45 WS customers later dropped the requirement for >= 60 kt wind warnings. During Phase II of this task, the AMU expanded the period of record (POR) by six years to increase the number of observations used to create the forecast equations. A large number of possible predictors were evaluated from archived soundings, including inversion depth and strength, low-level wind shear, mixing height, temperature lapse rate and winds from the surface to 3000 ft. Each day in the POR was stratified in a number of ways, such as by low-level wind direction, synoptic weather pattern, precipitation and Bulk Richardson number. The most accurate Phase II equations were then selected for an independent verification. The Phase I and II forecast methods were

  5. Health-hazard evaluation report HETA 84-427-1613, Pikes Peak Dialysis Center, Colorado Springs, Colorado

    SciTech Connect

    Pryor, P.

    1985-08-01

    Environmental and breathing zone samples were analyzed for formaldehyde at the Pikes Peak Dialysis Center, Colorado Springs, Colorado in August, 1984 and February, 1985. The evaluation was requested by a representative of the Center to determine if there was a health hazard due to formaldehyde. Eight employees were interviewed. The ventilation systems were investigated. Personal protective clothing was inspected. Breathing-zone samples contained 0 28 to 1.0 (mg/m/sup 3/) formaldehyde. The OSHA standard for formaldehyde is 3.7 mg/m/sup 3/. Area formaldehyde concentrations ranged from nondetectable to 0.75 mg/m/sup 3/. Health complaints reported included sore throat, congestion, cough, and eye, nose and throat irritation. Most of the complaints originated from employees in the formalin mixing, reuse sterilization, and dialysis unit packing sections. The exhaust system in the reuse sterilization area was not working efficiently. A variety of personal protective clothing was available including lab coats, protective goggles, aprons, respirators, and gloves. The author concludes that a health hazard from formaldehyde exposure exists at the facility. Recommendations include improving local exhaust ventilation in areas where formaldehyde is used extensively, avoiding skin and eye contact with formaldehyde, and training and educating employees in safe work practices.

  6. Lead Is Not Off Center in PbTe: The Importance of r-Space Phase Information in Extended X-Ray Absorption Fine Structure Spectroscopy

    NASA Astrophysics Data System (ADS)

    Keiber, T.; Bridges, F.; Sales, B. C.

    2013-08-01

    PbTe is a well-known thermoelectric material. Recent x-ray total scattering studies suggest that Pb moves off center along 100 in PbTe, by ˜0.2Å at 300 K, producing a split Pb-Te pair distribution. We present an extended x-ray absorption fine structure spectroscopy (EXAFS) study of PbTe (and Tl doped PbTe) to determine if Pb or Te is off center. EXAFS provides sensitive r- or k-space phase information which can differentiate between a split peak for the Pb-Te distribution (indicative of off-center Pb) and a thermally broadened peak. We find no evidence for a split peak for Pb-Te or Te-Pb. At 300 K, the vibration amplitude for Pb-Te (or Te-Pb) is large; this thermally induced disorder is indicative of weak bonds, and the large disorder is consistent with the low thermal conductivity at 300 K. We also find evidence of an anharmonic potential for the nearest Pb-Te bonds, consistent with the overall anharmonicity found for the phonon modes. This effect is modeled by a “skew” factor (C3) which significantly improves the fit of the Pb-Te and Te-Pb peaks for the high temperature EXAFS data; C3 becomes significant above approximately 150-200 K. The consequences of these results will be discussed.

  7. The origin of the split B800 absorption peak in the LH2 complexes from Allochromatium vinosum.

    PubMed

    Löhner, Alexander; Carey, Anne-Marie; Hacking, Kirsty; Picken, Nichola; Kelly, Sharon; Cogdell, Richard; Köhler, Jürgen

    2015-01-01

    The absorption spectrum of the high-light peripheral light-harvesting (LH) complex from the photosynthetic purple bacterium Allochromatium vinosum features two strong absorptions around 800 and 850 nm. For the LH2 complexes from the species Rhodopseudomonas acidophila and Rhodospirillum molischianum, where high-resolution X-ray structures are available, similar bands have been observed and were assigned to two pigment pools of BChl a molecules that are arranged in two concentric rings (B800 and B850) with nine (acidophila) or eight (molischianum) repeat units, respectively. However, for the high-light peripheral LH complex from Alc. vinosum, the intruiging feature is that the B800 band is split into two components. We have studied this pigment-protein complex by ensemble CD spectroscopy and polarisation-resolved single-molecule spectroscopy. Assuming that the high-light peripheral LH complex in Alc. vinosum is constructed on the same modular principle as described for LH2 from Rps. acidophila and Rsp. molischianum, we used those repeat units as a starting point for simulating the spectra. We find the best agreement between simulation and experiment for a ring-like oligomer of 12 repeat units, where the mutual arrangement of the B800 and B850 rings resembles those from Rsp. molischianum. The splitting of the B800 band can be reproduced if both an excitonic coupling between dimers of B800 molecules and their interaction with the B850 manifold are taken into account. Such dimers predict an interesting apoprotein organisation as discussed below. PMID:25150556

  8. H I absorption measurements over the Galactic center Radio Arc region

    NASA Technical Reports Server (NTRS)

    Lasenby, J.; Lasenby, A. N.; Yusef-Zadeh, F.

    1989-01-01

    The compact array of the VLA was used to study H I absorption in a 100-pc region in the center of the Galaxy. An absence of gas was observed at 40-50 km/s across the Radio Arc, suggesting that the '40 km/s molecular cloud' possibly associated with Sgr A is placed behind the Arc. At +20 km/s, the observations show absorption by material which could be depolarizing much of the synchrotron emission from the Arc filaments. The kinematic structure revealed by high-resolution molecular and radio recombination line observations is confirmed by the distribution of H I gas at -10 to -60 km/s.

  9. Hydrogen bonding between acetate-based ionic liquids and water: Three types of IR absorption peaks and NMR chemical shifts change upon dilution

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Cao, Yuanyuan; Zhang, Yuwei; Mu, Tiancheng

    2014-01-01

    The hydrogen-bonding interaction between acetate-based ionic liquids (AcIL) and water was investigated by attenuated total reflection infrared (ATR-IR) and 1H NMR. Interestingly, the relative change of chemical shift δ of 1H NMR upon dilution could be divided into three regions. All the H show an upfield shift in Regions 1 and 2 while a different tendency in Region 3 (upfield, no, and downfield shift classified as Types 1, 2, 3, respectively). For ATR-IR, the red, no, or blue shift of νOD (IR absorption peak of OD in D2O) and ν± (IR absorption peak of AcILs) also have three types, respectively. Two-Times Explosion Mechanism (TTEM) was proposed to interpret the dynamic processes of AcILs upon dilution macroscopically, meanwhile an Inferior Spring Model (ISM) was proposed to help to understand the TTEM microscopically, All those indicate that AcILs present the state of network, sub-network, cluster, sub-cluster, ion pairs and sub-ion pairs in sequence upon dilution by water and the elongation of hydrogen bonding between AcILs-water, between cation-anion of AcILs is plastic deformation rather than elastic deformation.

  10. Inhomogeneous broadening and peak shift of the 7.6 eV optical absorption band of oxygen vacancies in SiO{sub 2}

    SciTech Connect

    Kajihara, Koichi; Skuja, Linards; Hosono, Hideo

    2014-10-21

    The peak parameters of radiation-induced 7.6 eV optical absorption band of oxygen vacancies (Si-Si bonds) were examined for high-purity synthetic α-quartz and amorphous SiO{sub 2} (a‐SiO{sub 2}) exposed to {sup 60}Co γ-rays. The peak shape is asymmetric with the steeper edge at the lower energy side both in α-quartz and a‐SiO{sub 2}, and the peak energy is larger for α-quartz than that for a‐SiO{sub 2}. The full width at half maximum for a‐SiO{sub 2} is larger by ∼40-60% than that for α-quartz, and it increases with an increase in the disorder of the a‐SiO{sub 2} network, which is enhanced by raising the temperature of preannealing before irradiation, i.e., fictive temperature. These data are interpreted from the viewpoint of the site-to-site distribution of the Si-Si bond length in a‐SiO{sub 2}.

  11. Infrared absorption band and vibronic structure of the nitrogen-vacancy center in diamond

    NASA Astrophysics Data System (ADS)

    Kehayias, P.; Doherty, M. W.; English, D.; Fischer, R.; Jarmola, A.; Jensen, K.; Leefer, N.; Hemmer, P.; Manson, N. B.; Budker, D.

    2013-10-01

    Negatively charged nitrogen-vacancy (NV-) color centers in diamond have generated much interest for use in quantum technology. Despite the progress made in developing their applications, many questions about the basic properties of NV- centers remain unresolved. Understanding these properties can validate theoretical models of NV-, improve their use in applications, and support their development into competitive quantum devices. In particular, knowledge of the phonon modes of the 1A1 electronic state is key for understanding the optical pumping process. Using pump-probe spectroscopy, we measured the phonon sideband of the 1E→1A1 electronic transition in the NV- center. From this we calculated the 1E→1A1 one-phonon absorption spectrum and found it to differ from that of the 3E→3A2 transition, a result which is not anticipated by previous group-theoretical models of the NV- electronic states. We identified a high-energy 169-meV localized phonon mode of the 1A1 level.

  12. Statistical Short-Range Guidance for Peak Wind Forecasts on Kennedy Space Center/Cape Canaveral Air Force Station, Phase III

    NASA Technical Reports Server (NTRS)

    Crawford, Winifred

    2010-01-01

    This final report describes the development of a peak wind forecast tool to assist forecasters in determining the probability of violating launch commit criteria (LCC) at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The peak winds are an important forecast element for both the Space Shuttle and Expendable Launch Vehicle (ELV) programs. The LCC define specific peak wind thresholds for each launch operation that cannot be exceeded in order to ensure the safety of the vehicle. The 45th Weather Squadron (45 WS) has found that peak winds are a challenging parameter to forecast, particularly in the cool season months of October through April. Based on the importance of forecasting peak winds, the 45 WS tasked the Applied Meteorology Unit (AMU) to develop a short-range peak-wind forecast tool to assist in forecasting LCC violations.The tool includes climatologies of the 5-minute mean and peak winds by month, hour, and direction, and probability distributions of the peak winds as a function of the 5-minute mean wind speeds.

  13. Peak Wind Forecasts for the Launch-Critical Wind Towers on Kennedy Space Center/Cape Canaveral Air Force Station, Phase IV

    NASA Technical Reports Server (NTRS)

    Crawford, Winifred

    2011-01-01

    This final report describes the development of a peak wind forecast tool to assist forecasters in determining the probability of violating launch commit criteria (LCC) at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The peak winds arc an important forecast clement for both the Space Shuttle and Expendable Launch Vehicle (ELV) programs. The LCC define specific peak wind thresholds for each launch operation that cannot be exceeded in order to ensure the safety of the vehicle. The 45th Weather Squadron (45 WS) has found that peak winds are a challenging parameter to forecast, particularly in the cool season months of October through April. Based on the importance of forecasting peak winds, the 45 WS tasked the Applied Meteorology Unit (AMU) to update the statistics in the current peak-wind forecast tool to assist in forecasting LCC violations. The tool includes onshore and offshore flow climatologies of the 5-minute mean and peak winds and probability distributions of the peak winds as a function of the 5-minute mean wind speeds.

  14. Effects of Fusion Zone Size and Failure Mode on Peak Load and Energy Absorption of Advanced High Strength Steel Spot Welds

    SciTech Connect

    Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.

    2007-01-01

    This paper examines the effects of fusion zone size on failure modes, static strength and energy absorption of resistance spot welds (RSW) of advanced high strength steels (AHSS). DP800 and TRIP800 spot welds are considered. The main failure modes for spot welds are nugget pullout and interfacial fracture. Partial interfacial fracture is also observed. The critical fusion zone sizes to ensure nugget pull-out failure mode are developed for both DP800 and TRIP800 using limit load based analytical model and micro-hardness measurements of the weld cross sections. Static weld strength tests using cross tension samples were performed on the joint populations with controlled fusion zone sizes. The resulted peak load and energy absorption levels associated with each failure mode were studied for all the weld populations using statistical data analysis tools. The results in this study show that AHSS spot welds with fusion zone size of can not produce nugget pullout mode for both the DP800 and TRIP800 materials examined. The critical fusion zone size for nugget pullout shall be derived for individual materials based on different base metal properties as well as different heat affected zone (HAZ) and weld properties resulted from different welding parameters.

  15. An x-ray absorption study of the iron site in bacterial photosynthetic reaction centers.

    PubMed Central

    Bunker, G; Stern, E A; Blankenship, R E; Parson, W W

    1982-01-01

    Measurements were made of the extended x-ray absorption fine structure (EXAFS) of the iron site in photosynthetic reaction centers from the bacterium Rhodopseudomonas sphaeroides. Forms with two quinones, two quinones with added o-phenanthroline, and one quinone were studied. Only the two forms containing two quinones maintained their integrity and were analyzed. The spectra show directly that the added o-phenanthroline does not chelate the iron atom. Further analysis indicates that the iron is octahedrally coordinated by nitrogen and/or oxygen atoms located at various distances, with the average value of about 2.14 A. The analysis suggests that most of the ligands are nitrogens and that three of the nitrogen ligands belong to histidine rings. This interpretation accounts for several unusual features of the EXAFS spectrum. We speculate that the quinones are bound to the histidine rings in some manner. Qualitative features of the absorption edge spectra also are discussed and are related to the Fe-ligand distance. PMID:6977382

  16. Tool for Forecasting Cool-Season Peak Winds Across Kennedy Space Center and Cape Canaveral Air Force Station (CCAFS)

    NASA Technical Reports Server (NTRS)

    Barrett, Joe H., III; Roeder, William P.

    2010-01-01

    Peak wind speed is important element in 24-Hour and Weekly Planning Forecasts issued by 45th Weather Squadron (45 WS). Forecasts issued for planning operations at KSC/CCAFS. 45 WS wind advisories issued for wind gusts greater than or equal to 25 kt. 35 kt and 50 kt from surface to 300 ft. AMU developed cool-season (Oct - Apr) tool to help 45 WS forecast: daily peak wind speed, 5-minute average speed at time of peak wind, and probability peak speed greater than or equal to 25 kt, 35 kt, 50 kt. AMU tool also forecasts daily average wind speed from 30 ft to 60 ft. Phase I and II tools delivered as a Microsoft Excel graphical user interface (GUI). Phase II tool also delivered as Meteorological Interactive Data Display System (MIDDS) GUI. Phase I and II forecast methods were compared to climatology, 45 WS wind advisories and North American Mesoscale model (MesoNAM) forecasts in a verification data set.

  17. Education, Technology, and Media: A Peak into My Summer Internship at NASA Glenn Research Center in Cleveland, Ohio

    NASA Technical Reports Server (NTRS)

    Moon, James

    2004-01-01

    My name is James Moon and I am a senor at Tennessee State University where my major is Aeronautical and Industrial Technology with a concentration in industrial electronics. I am currently serving my internship in the Engineering and Technical Services Directorate at the Glenn Research Center (GRC). The Engineering and Technical Service Directorate provides the services and infrastructure for the Glenn Research Center to take research concepts to reality. They provide a full range of integrated services including engineering, advanced prototyping and testing, facility management, and information technology for NASA, industry, and academia. Engineering and Technical Services contains the core knowledge in Information Technology (IT). This includes data systems and analysis, inter and intranet based systems design and data security. Including the design and development of embedded real-time sohare applications for flight and supporting ground systems, Engineering and Technical Services provide a wide range of IT services and products specific to the Glenn Research Center research and engineering community.

  18. Direct observation of vibrational coherence in bacterial reaction centers using femtosecond absorption spectroscopy.

    PubMed

    Vos, M H; Lambry, J C; Robles, S J; Youvan, D C; Breton, J; Martin, J L

    1991-10-15

    It is shown that vibrational coherence modulates the femtosecond kinetics of stimulated emission and absorption of reaction centers of purple bacteria. In the DLL mutant of Rhodobacter capsulatus, which lacks the bacteriopheophytin electron acceptor, oscillations with periods of approximately 500 fs and possibly also of approximately 2 ps were observed, which are associated with formation of the excited state. The kinetics, which reflect primary processes in Rhodobacter sphaeroides R-26, were modulated by oscillations with a period of approximately 700 fs at 796 nm and approximately 2 ps at 930 nm. In the latter case, at 930 nm, where the stimulated emission of the excited state, P*, is probed, oscillations could only be resolved when a sufficiently narrow (10 nm) and concomitantly long pump pulse was used. This may indicate that the potential energy surface of the excited state is anharmonic or that low-frequency oscillations are masked when higher frequency modes are also coherently excited, or both. The possibility is discussed that the primary charge separation may be a coherent and adiabatic process coupled to low-frequency vibrational modes. PMID:1924348

  19. Global absorption center map of the mafic minerals on the Moon as viewed by CE-1 IIM data

    NASA Astrophysics Data System (ADS)

    Wu, Yunzhao; Zhang, Xia; Yan, Bokun; Gan, Fuping; Tang, Zesheng; Xu, Aoao; Zheng, Yongchun; Zou, Yongliao

    2010-12-01

    Determining the global distribution of minerals on the Moon has been an important goal of lunar science. Hyperspectral remote sensing is an important approach to acquiring minerals on the Moon on the global scale. The wavelength of the absorption band center is the key parameter for identifying minerals with reflectance spectra as well as remote sensing data. The global absorption center map of the mafic minerals of the Moon was produced for the first time with the Chang'E-1 IIM data. This map shows the global distribution of mafic minerals such as orthopyroxenes, clinopyroxenes, and olivine and even plagioclase feldspar of the Moon. The validation for some representative areas indicates that the global map is reliable and even more detailed than the results derived from Clementine-data. Moreover, our method is insensitive to the topography and viewing and illumination geometries. The global absorption band center map not only contributes to the lunar science research, but also has other implications to be further studied. Moreover, the preprocessing methods such as calibration and correction introduced in this study can be useful in other research with IIM data.

  20. Calculation method using Clarkson integration for the physical dose at the center of the spread-out Bragg peak in carbon-ion radiotherapy

    SciTech Connect

    Tajiri, Minoru; Maeda, Takamasa; Isobe, Yoshiharu; Kuroiwa, Toshitaka; Tanimoto, Katsuyuki; Shibayama, Koichi; Koba, Yusuke; Fukuda, Shigekazu

    2013-07-15

    Purpose: In broad-beam carbon-ion radiotherapy performed using the heavy-ion medical accelerator in Chiba, the number of monitor units is determined by measuring the physical dose at the center of the spread-out Bragg peak (SOBP) for the treatment beam. The total measurement time increases as the number of treatment beams increases, which hinders the treatment of an increased number of patients. Hence, Kusano et al.[Jpn. J. Med. Phys. 23(Suppl. 2), 65-68 (2003)] proposed a method to calculate the physical dose at the center of the SOBP for a treatment beam. Based on a recent study, the authors here propose a more accurate calculation method.Methods: The authors measured the physical dose at the center of the SOBP while varying the circular field size and range-shifter thickness. The authors obtained the physical dose at the center of the SOBP for an irregularly shaped beam using Clarkson integration based on these measurements.Results: The difference between the calculated and measured physical doses at the center of the SOBP varied with a change in the central angle of the sector segment. The differences between the calculated and measured physical doses at the center of the SOBP were within {+-}1% for all irregularly shaped beams that were used to validate the calculation method.Conclusions: The accuracy of the proposed method depends on both the number of angular intervals used for Clarkson integration and the fineness of the basic data used for calculations: sampling numbers for the field size and thickness of the range shifter. If those parameters are properly chosen, the authors can obtain a calculated monitor unit number with high accuracy sufficient for clinical applications.

  1. Characterization of the particulate methane monooxygenase metal centers in multiple redox states by X-ray absorption spectroscopy.

    PubMed

    Lieberman, Raquel L; Kondapalli, Kalyan C; Shrestha, Deepak B; Hakemian, Amanda S; Smith, Stephen M; Telser, Joshua; Kuzelka, Jane; Gupta, Rajeev; Borovik, A S; Lippard, Stephen J; Hoffman, Brian M; Rosenzweig, Amy C; Stemmler, Timothy L

    2006-10-01

    The integral membrane enzyme particulate methane monooxygenase (pMMO) converts methane, the most inert hydrocarbon, to methanol under ambient conditions. The 2.8-A resolution pMMO crystal structure revealed three metal sites: a mononuclear copper center, a dinuclear copper center, and a nonphysiological mononuclear zinc center. Although not found in the crystal structure, solution samples of pMMO also contain iron. We have used X-ray absorption spectroscopy to analyze the oxidation states and coordination environments of the pMMO metal centers in as-isolated (pMMO(iso)), chemically reduced (pMMO(red)), and chemically oxidized (pMMO(ox)) samples. X-ray absorption near-edge spectra (XANES) indicate that pMMO(iso) contains both Cu(I) and Cu(II) and that the pMMO Cu centers can undergo redox chemistry. Extended X-ray absorption fine structure (EXAFS) analysis reveals a Cu-Cu interaction in all redox forms of the enzyme. The Cu-Cu distance increases from 2.51 to 2.65 A upon reduction, concomitant with an increase in the average Cu-O/N bond lengths. Appropriate Cu2 model complexes were used to refine and validate the EXAFS fitting protocols for pMMO(iso). Analysis of Fe EXAFS data combined with electron paramagnetic resonance (EPR) spectra indicates that Fe, present as Fe(III), is consistent with heme impurities. These findings are complementary to the crystallographic data and provide new insight into the oxidation states and possible electronic structures of the pMMO Cu ions. PMID:16999437

  2. X-ray absorption spectroscopic studies of the dinuclear iron center in methane monooxygenase and the sulfure and chlorine centers in photographic materials

    SciTech Connect

    DeWitt, J.G.

    1992-12-01

    The dinuclear iron center of the hydroxylase component of soluble methane monooxygenase (MMO) from Methylococcus capsulatus and Methylosinus trichosporiwn has been studied by X-ray absorption spectroscopy. Analysis of the Fe K-edge EXAFS revealed that the first shell coordination of the Fe(HI)Fe(IH) oxidized state of the hydroxylase from M. capsulatus consists of approximately 6 N and 0 atoms at an average distance of 2.04 [Angstrom]. The Fe-Fe distance was determined to be 3.4 [Angstrom]. No evidence for the presence of a short oxo bridge in the iron center of the oxidized hydroxylase was found, suggesting that the active site of MMO is significantly different from the active sites of the dinuclear iron proteins hemery and ribonucleotide reductase. In addition, the results of the first shell fits suggest that there are more oxygen than nitrogen donor ligands.

  3. X-ray absorption spectroscopic studies of the dinuclear iron center in methane monooxygenase and the sulfure and chlorine centers in photographic materials

    SciTech Connect

    DeWitt, J.G.

    1992-12-01

    The dinuclear iron center of the hydroxylase component of soluble methane monooxygenase (MMO) from Methylococcus capsulatus and Methylosinus trichosporiwn has been studied by X-ray absorption spectroscopy. Analysis of the Fe K-edge EXAFS revealed that the first shell coordination of the Fe(HI)Fe(IH) oxidized state of the hydroxylase from M. capsulatus consists of approximately 6 N and 0 atoms at an average distance of 2.04 {Angstrom}. The Fe-Fe distance was determined to be 3.4 {Angstrom}. No evidence for the presence of a short oxo bridge in the iron center of the oxidized hydroxylase was found, suggesting that the active site of MMO is significantly different from the active sites of the dinuclear iron proteins hemery and ribonucleotide reductase. In addition, the results of the first shell fits suggest that there are more oxygen than nitrogen donor ligands.

  4. HCO{sup +} AND HCN J = 3-2 ABSORPTION TOWARD THE CENTER OF CENTAURUS A

    SciTech Connect

    Muller, Sebastien; Dinh-V-Trung

    2009-05-01

    We have investigated the presence of dense gas toward the radio source Cen A by looking at the absorption of the HCO{sup +} and HCN (3-2) lines in front of the bright continuum source with the Submillimeter Array. We detect narrow HCO{sup +} (3-2) absorption, and tentatively HCN (3-2), close to the systemic velocity. For both molecules, the J = 3 - 2 absorption is much weaker than for the J = 1 - 0 line. From simple excitation analysis, we conclude that the gas density is of the order of a few 10{sup 4} cm{sup -3} for a column density N(HCO{sup +})/{delta}V of 3 x 10{sup 12} cm{sup -2} km{sup -1} s and a kinetic temperature of 10 K. In particular, we find no evidence for molecular gas density higher than a few 10{sup 4} cm{sup -3} on the line of sight to the continuum source. We discuss the implications of our finding on the nature of the molecular gas responsible for the absorption toward Cen A.

  5. Improving calibration of two key parameters in Hydrologic Engineering Center hydrologic modelling system, and analysing the influence of initial loss on flood peak flows.

    PubMed

    Lin, Musheng; Chen, Xingwei; Chen, Ying; Yao, Huaxia

    2013-01-01

    Parameter calibration is a key and difficult issue for a hydrological model. Taking the Jinjiang Xixi watershed of south-east China as the study area, we proposed methods to improve the calibration of two very sensitive parameters, Muskingum K and initial loss, in the Hydrologic Engineering Center hydrologic modelling system (HEC-HMS) model. Twenty-three rainstorm flood events occurring from 1972 to 1977 were used to calibrate the model using a trial-and-error approach, and a relationship between initial loss and initial discharge for these flood events was established; seven rainstorm events occurring from 1978 to 1979 were used to validate the two parameters. The influence of initial loss change on different return-period floods was evaluated. A fixed Muskingum K value, which was calibrated by assuming a flow wave velocity at 3 m/s, could be used to simulate a flood hydrograph, and the empirical power-function relationship between initial loss and initial discharge made the model more applicable for flood forecasting. The influence of initial loss on peak floods was significant but not identical for different flood levels, and the change rate of peak floods caused by the same initial loss change was more remarkable when the return period increased. PMID:24355863

  6. Effect of radiation-induced color centers absorption in optical fibers on fiber optic gyroscope for space application

    NASA Astrophysics Data System (ADS)

    Jin, Jing; Li, Ya; Zhang, Zu-Chen; Wu, Chun-Xiao; Song, Ning-Fang

    2016-08-01

    The effects of color centers’ absorption on fibers and interferometric fiber optical gyroscopes (IFOGs) are studied in the paper. The irradiation induced attenuation (RIA) spectra of three types of polarization-maintaining fibers (PMFs), i.e., P-doped, Ge-doped, and pure silica, irradiated at 100 Gy and 1000 Gy are measured in a wavelength range from 1100 nm to 1600 nm and decomposed according to the Gaussian model. The relationship of the color centers absorption intensity with radiation dose is investigated based on a power model. Furthermore, the effects of all color centers’ absorption on RIA and mean wavelength shifts (MWS) at 1300 nm and 1550 nm are discussed respectively. Finally, the random walk coefficient (RWC) degradation induced from RIA and the scale factor error induced by MWS of the IFOG are simulated and tested at a wavelength of 1300 nm. This research will contribute to the applications of the fibers in radiation environments. Project supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, China.

  7. A HIGH-RESOLUTION SURVEY OF H I ABSORPTION TOWARD THE CENTRAL 200 pc OF THE GALACTIC CENTER

    SciTech Connect

    Lang, Cornelia C.; Clubb, Kelsey I.; Goss, W. M.; Cyganowski, Claudia

    2010-12-15

    We present an H I absorption survey of the central 250 pc of the Galaxy. Very Large Array observations were made at 21 cm in the DnC and CnB configurations and have a resolution of {approx}15'' (0.6 pc at the Galactic center (GC) distance) and a velocity resolution of {approx}2.5 km s{sup -1}. This study provides H I data with high spatial resolution, comparable with the many high-resolution observations which have been made of GC sources over the past 10 years. Here we present an overview of the H I absorption toward {approx}40 well-known continuum sources and a detailed comparison of the ionized, atomic, and molecular components of the interstellar medium for the Sgr B, Radio Arc, and Sgr C regions. In these well-known regions, the atomic gas appears to be closely correlated in both velocity and distribution to the ionized and molecular gas, indicating that it resides in photodissociation regions related to the H II regions in the GC. Toward the majority of the radio continuum sources, H I absorption by the 3 kpc arm is detected, constraining these sources to lie beyond a 5 kpc distance in the Galaxy.

  8. X-ray absorption spectroscopic studies of the dinuclear iron center in methane monooxygenase and the sulfur and chlorine centers in photographic materials

    SciTech Connect

    DeWitt, J.G.

    1993-01-01

    The dinuclear iron center of the hydroxylase component of soluble methane monooxygenase (MMO) from Methylococcus capsulatus (Bath) and Methylosinus trichosporium (OB3b) has been studied by X-ray absorption spectroscopy. Analysis of the Fe K-edge EXAFS revealed that the first shell coordination of the hydroxylase consists of [approximately]6 N and O atoms at an average distance of 2.04[angstrom] in the oxidized form, increasing to 2.06-2.09[angstrom] in the semimet form, and 2.15 [angstrom] for the oxidized and semimet hydroxylase samples. No evidence for the presence of a short oxo bridge in the iron center was found. The presence of component B, the regulatory protein of the MMO enzyme system, had an effect on the distance distribution of first shell atoms in the hydroyxlase active site. No evidence of a Br contribution was seen in the hydroxylase EXAFS in the presence of a brominated substrate, suggesting the substrate binds more than 4[angstrom] from the iron center. An investigation of the EXAFS analysis technique using structurally-characterized iron dimers demonstrated that the results of the second shell fits exhibit a bias for the Fe-FE distance of the model compound from which the fitting parameters were obtained. An asymmetric pre-edge feature in the edge spectra of iron dimers was characteristic of oxo-bridge compounds, while a split pre-edge was characteristic of non-oxo-bridged compounds. Spectral sensitizing dyes and chemical sensitizing centers of importance to the photographic system were characterized by S and Cl K-edge X-ray absorption spectroscopy. The appearance of the S K-edge spectra was characteristic of the environment of the S atoms and oriented single-crystal studies permitted the assignment of the features. The nature and extend of interaction between S and Ag and Au was characterized using XAS and used to investigate the nature of the interaction between photographic dyes and the AgBr substrate.

  9. Negligible shift of 3Ag- potential in longer-chain carotenoids as revealed by a single persistent peak of 3Ag-→1Ag- stimulated emission followed by 3Ag-←1Ag- transient-absorption

    NASA Astrophysics Data System (ADS)

    Li, Chunyong; Miki, Takeshi; Kakitani, Yoshinori; Koyama, Yasushi; Nagae, Hiroyoshi

    2007-12-01

    Upon excitation of lycopene, anhydrorhodovibrin or spirilloxanthin to the 1Bu+(0) state, stimulated emission followed by transient-absorption was observed as a single peak with the 3Ag-(0) energy that had been determined by measurement of resonance-Raman excitation profiles. This observation was explained in terms of negligible shift of the 3Ag- potential, in reference to the 1Ag- potential, where only the 3Ag-(υ)→1Ag-(υ) emission and the 3Ag-(υ)←1Ag-(υ) absorption become allowed during the vibrational relaxation of υ = 2 → 1 → 0, starting from the 3Ag-(2) level generated by diabatic internal conversion from the 1Bu+(0) level, in anhydrorhodovibrin, for example.

  10. Total Absorption Gamma-ray Spectrometer (TAGS) Intensity Distributions from INL's Gamma-Ray Spectrometry Center

    DOE Data Explorer

    Greenwood, R. E.

    A 252Cf fission-product source and the INL on-line isotope separator were used to supply isotope-separated fission-product nuclides to a total absorption -ray spectrometer. This spectrometer consisted of a large (25.4-cm diameter x 30.5-cm long) NaI(Tl) detector with a 20.3-cm deep axial well in which is placed a 300-mm2 x 1.0-mm Si detector. The spectra from the NaI(Tl) detector are collected both in the singles mode and in coincidence with the B-events detected in the Si detector. Ideally, this detector would sum all the energy of the B- rays in each cascade following the population of daughter level by B- decay, so that the event could be directly associated with a particular daughter level. However, there are losses of energy from attenuation of the rays before they reach the detector, transmission of rays through the detector, escape of secondary photons from Compton scattering, escape of rays through the detector well, internal conversion, etc., and the measured spectra are thus more complicated than the ideal case and the analysis is more complex. Analysis methods have been developed to simulate all of these processes and thus provide a direct measure of the B- intensity distribution as a function of the excitation energy in the daughter nucleus. These data yield more accurate information on the B- distribution than conventional decay-scheme studies for complex decay schemes with large decay energies, because in the latter there are generally many unobserved and observed but unplaced rays. The TAGS data have been analyzed and published [R. E. Greenwood et al., Nucl Instr. and metho. A390(1997)] for 40 fission product-nuclides to determine the B- intensity distributions. [Copied from the TAGS page at http://www.inl.gov/gammaray/spectrometry/tags.shtml]. Those values are listed on this page for quick reference.

  11. Statistical Short-Range Guidance for Peak Wind Speed Forecasts on Kennedy Space Center/Cape Canaveral Air Force Station: Phase I Results

    NASA Technical Reports Server (NTRS)

    Lambert, Winifred C.; Merceret, Francis J. (Technical Monitor)

    2002-01-01

    This report describes the results of the ANU's (Applied Meteorology Unit) Short-Range Statistical Forecasting task for peak winds. The peak wind speeds are an important forecast element for the Space Shuttle and Expendable Launch Vehicle programs. The Keith Weather Squadron and the Spaceflight Meteorology Group indicate that peak winds are challenging to forecast. The Applied Meteorology Unit was tasked to develop tools that aid in short-range forecasts of peak winds at tower sites of operational interest. A 7 year record of wind tower data was used in the analysis. Hourly and directional climatologies by tower and month were developed to determine the seasonal behavior of the average and peak winds. In all climatologies, the average and peak wind speeds were highly variable in time. This indicated that the development of a peak wind forecasting tool would be difficult. Probability density functions (PDF) of peak wind speed were calculated to determine the distribution of peak speed with average speed. These provide forecasters with a means of determining the probability of meeting or exceeding a certain peak wind given an observed or forecast average speed. The climatologies and PDFs provide tools with which to make peak wind forecasts that are critical to safe operations.

  12. A practical method for determining γ-ray full-energy peak efficiency considering coincidence-summing and self-absorption corrections for the measurement of environmental samples after the Fukushima reactor accident

    NASA Astrophysics Data System (ADS)

    Shizuma, Kiyoshi; Oba, Yurika; Takada, Momo

    2016-09-01

    A method for determining the γ-ray full-energy peak efficiency at positions close to three Ge detectors and at the well port of a well-type detector was developed for measuring environmental volume samples containing 137Cs, 134Cs and 40K. The efficiency was estimated by considering two correction factors: coincidence-summing and self-absorption corrections. The coincidence-summing correction for a cascade transition nuclide was estimated by an experimental method involving measuring a sample at the far and close positions of a detector. The derived coincidence-summing correction factors were compared with those of analytical and Monte Carlo simulation methods and good agreements were obtained. Differences in the matrix of the calibration source and the environmental sample resulted in an increase or decrease of the full-energy peak counts due to the self-absorption of γ-rays in the sample. The correction factor was derived as a function of the densities of several matrix materials. The present method was applied to the measurement of environmental samples and also low-level radioactivity measurements of water samples using the well-type detector.

  13. Multiple Scattering X-Ray Absorption Studies of Zn2+ Binding Sites in Bacterial Photosynthetic Reaction Centers

    PubMed Central

    Giachini, Lisa; Francia, Francesco; Mallardi, Antonia; Palazzo, Gerardo; Carpenè, Emilio; Boscherini, Federico; Venturoli, Giovanni

    2005-01-01

    Binding of transition metal ions to the reaction center (RC) protein of the photosynthetic bacterium Rhodobacter sphaeroides has been previously shown to slow light-induced electron and proton transfer to the secondary quinone acceptor molecule, QB. On the basis of x-ray diffraction at 2.5 Å resolution a site, formed by AspH124, HisH126, and HisH128, has been identified at the protein surface which binds Cd2+ or Zn2+. Using Zn K-edge x-ray absorption fine structure spectroscopy we report here on the local structure of Zn2+ ions bound to purified RC complexes embedded into polyvinyl alcohol films. X-ray absorption fine structure data were analyzed by combining ab initio simulations and multiparameter fitting; structural contributions up to the fourth coordination shell and multiple scattering paths (involving three atoms) have been included. Results for complexes characterized by a Zn to RC stoichiometry close to one indicate that Zn2+ binds two O and two N atoms in the first coordination shell. Higher shell contributions are consistent with a binding cluster formed by two His, one Asp residue, and a water molecule. Analysis of complexes characterized by ∼2 Zn ions per RC reveals a second structurally distinct binding site, involving one O and three N atoms, not belonging to a His residue. The local structure obtained for the higher affinity site nicely fits the coordination geometry proposed on the basis of x-ray diffraction data, but detects a significant contraction of the first shell. Two possible locations of the second new binding site at the cytoplasmic surface of the RC are proposed. PMID:15613631

  14. Body centered cubic magnesium niobium hydride with facile room temperature absorption and four weight percent reversible capacity.

    PubMed

    Tan, XueHai; Wang, Liya; Holt, Chris M B; Zahiri, Beniamin; Eikerling, Michael H; Mitlin, David

    2012-08-21

    We have synthesized a new metastable metal hydride with promising hydrogen storage properties. Body centered cubic (bcc) magnesium niobium hydride (Mg(0.75)Nb(0.25))H(2) possesses 4.5 wt% hydrogen gravimetric density, with 4 wt% being reversible. Volumetric hydrogen absorption measurements yield an enthalpy of hydride formation of -53 kJ mol(-1) H(2), which indicates a significant thermodynamic destabilization relative to the baseline -77 kJ mol(-1) H(2) for rutile MgH(2). The hydrogenation cycling kinetics are remarkable. At room temperature and 1 bar hydrogen it takes 30 minutes to absorb a 1.5 μm thick film at sorption cycle 1, and 1 minute at cycle 5. Reversible desorption is achieved in about 60 minutes at 175 °C. Using ab initio calculations we have examined the thermodynamic stability of metallic alloys with hexagonal close packed (hcp) versus bcc crystal structure. Moreover we have analyzed the formation energies of the alloy hydrides that are bcc, rutile or fluorite. PMID:22782120

  15. Band Structure of the Rhodobacter sphaeroides Photosynthetic Reaction Center from Low-Temperature Absorption and Hole-Burned Spectra.

    PubMed

    Rancova, Olga; Jankowiak, Ryszard; Kell, Adam; Jassas, Mahboobe; Abramavicius, Darius

    2016-06-30

    Persistent/transient spectral hole burning (HB) and computer simulations are used to provide new insight into the excitonic structure and excitation energy transfer of the widely studied bacterial reaction center (bRC) of Rhodobacter (Rb.) sphaeroides. We focus on site energies of its cofactors and electrochromic shifts induced in the chemically oxidized (P(+)) and charge-separated (P(+)QM(-)) states. Theoretical models lead to two alternative interpretations of the H-band. On the basis of our experimental and simulation data, we suggest that the bleach near 813-825 nm in transient HB spectra in the P(+)QM(-) state, often assigned to the upper exciton component of the special pair, is mostly due to different electrochromic shifts of the BL/M cofactors. From the exciton compositions in the charge-neutral (CN) bRC, the weak fourth excitonic band near 780 nm can be denoted PY+, that is, the upper excitonic band of the special pair, which in the CN bRC behaves as a delocalized state over PM and PL pigments that weakly mixes with accessory BChls. Thus, the shoulder in the absorption of Rb. sphaeroides near 813-815 nm does not contain the PY+ exciton band. PMID:27266271

  16. Time-dependent absorption of very high-energy gamma-rays from the Galactic center by pair-production

    SciTech Connect

    Abramowski, Attila; Horns, Dieter; Ripken, Joachim; Gillessen, Stefan; Eldik, Christopher van

    2008-12-24

    Very high energy (VHE) gamma-rays have been detected from the direction of the Galactic center. The H.E.S.S. Cherenkov telescopes have located this {gamma}-ray source with a preliminary position uncertainty of 8.5'' per axis (6'' statistic+6'' sytematic per axis). Within the uncertainty region several possible counterpart candidates exist: the Super Massive Black Hole Sgr A*, the Pulsar Wind Nebula candidate G359.95-0.04, the Low Mass X-Ray Binary-system J174540.0-290031, the stellar cluster IRS 13, as well as self-annihilating dark matter. It is experimentally very challenging to further improve the positional accuracy in this energy range and therefore, it may not be possible to clearly associate one of the counterpart candidates with the VHE-source. Here, we present a new method to investigate a possible link of the VHE-source with the near environment of Sgr A*(within approximately 1000 Schwarzschild radii). This method uses the time- and energy-dependent effect of absorption of VHE {gamma}-rays by pair-production (in the following named pair-eclipse) with low-energy photons of stars closely orbiting the SMBH Sgr A*.

  17. First Ground-Based Infrared Solar Absorption Measurements of Free Tropospheric Methanol (CH3OH): Multidecade Infrared Time Series from Kitt Peak (31.9 deg N 111.6 deg W): Trend, Seasonal Cycle, and Comparison with Previous Measurements

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Mahieu, Emmanuel; Chiou, Linda; Herbin, Herve

    2009-01-01

    Atmospheric CH3OH (methanol) free tropospheric (2.09-14-km altitude) time series spanning 22 years has been analyzed on the basis of high-spectral resolution infrared solar absorption spectra of the strong vs band recorded from the U.S. National Solar Observatory on Kitt Peak (latitude 31.9degN, 111.6degW, 2.09-km altitude) with a 1-m Fourier transform spectrometer (FTS). The measurements span October 1981 to December 2003 and are the first long time series of CH3OH measurements obtained from the ground. The results were analyzed with SFIT2 version 3.93 and show a factor of three variations with season, a maximum at the beginning of July, a winter minimum, and no statistically significant long-term trend over the measurement time span.

  18. First Ground-Based Infrared Solar Absorption Measurements of Free Tropospheric Methanol (CH3OH): Multidecade Infrared Time Series from Kitt Peak (31.9 deg N 111.6 deg W): Trend, Seasonal Cycle, and Comparison with Previous Measurements

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Mahieu, Emmanuel; Chiou, Linda; Herbin, Herve

    2009-01-01

    Atmospheric CH3OH (methanol) free tropospheric (2.09-14-km altitude) time series spanning 22 years has been analyzed on the basis of high-spectral resolution infrared solar absorption spectra of the strong n8 band recorded from the U.S. National Solar Observatory on Kitt Peak (latitude 31.9degN, 111.6degW, 2.09-km altitude) with a 1-m Fourier transform spectrometer (FTS). The measurements span October 1981 to December 2003 and are the first long time series of CH3OH measurements obtained from the ground. The results were analyzed with SFIT2 version 3.93 and show a factor of three variations with season, a maximum at the beginning of July, a winter minimum, and no statistically significant long-term trend over the measurement time span.

  19. Two density peaks in low magnetic field helicon plasma

    SciTech Connect

    Wang, Y.; Zhao, G.; Ouyang, J. T. E-mail: lppmchenqiang@hotmail.com; Liu, Z. W.; Chen, Q. E-mail: lppmchenqiang@hotmail.com

    2015-09-15

    In this paper, we report two density peaks in argon helicon plasma under an axial magnetic field from 0 G to 250 G with Boswell-type antenna driven by radio frequency (RF) power of 13.56 MHz. The first peak locates at 40–55 G and the second one at 110–165 G, as the RF power is sustainably increased from 100 W to 250 W at Ar pressure of 0.35 Pa. The absorbed power of two peaks shows a linear relationship with the magnetic field. End views of the discharge taken by intensified charge coupled device reveal that, when the first peak appeared, the discharge luminance moves to the edge of the tube as the magnetic field increases. For the second peak, the strong discharge area is centered at the two antenna legs after the magnetic field reaches a threshold value. Comparing with the simulation, we suggest that the efficient power absorption of two peaks at which the efficient power absorption mainly appears in the near-antenna region is due to the mode conversion in bounded non-uniform helicon plasma. The two low-field peaks are caused, to some extent, by the excitation of Trivelpiece-Gould wave through non-resonance conversion.

  20. Estimation of plant water content by spectral absorption features centered at 1,450 nm and 1,940 nm regions.

    PubMed

    Wang, Jie; Xu, Ruisong; Yang, Shilun

    2009-10-01

    Vegetation water content could possibly provide widespread utility in agriculture, forestry and hydrology. In this article, three species leaves were measured radiometrically in order to determine a relationship between leaf water status and the spectral feature centered at 1,450 and 1,940 nm where there are strong water absorptions. The first step of our research is to measure leaf spectra with a FieldSpec-FR. After the spectral analysis using the continuum removal technique, the spectral absorption feature parameters: absorption band depth (D (1450), D (1940)), the normalized band depth of absorption in 1,450 and 1,940 nm (BNA(1450), BNA(1940)), the ratio of the two reflectance of continuum line (R (1450i )/R (1940i )), the ratio of the two band depth (D (1450)/D (1940)) and the ratio of the two absorption areas (A (1450)/A (1940)) in the two wavebands were extracted from each leaf spectrum. The fuel moisture content (FMC), specific leaf weight (SLW), equivalent water thickness (EWT) were measured for each leaf sample. A correlation analysis was conducted between the spectral absorption feature parameters and corresponding FMC, SLW and EWT. In addition, some existing indices for assessing water status such as WI (water index), WI/NDVI (water index/normalized difference vegetation index), MSI (moisture stress index), NDWI (normalized difference water index)were calculated and the correlation between them and water status were analyzed too. The results by comparing the correlations indicated that the spectral absorption feature indices we proposed were better. The indexes BNA(1940), D (1450)/D (1940), and A (1450)/A (1940) were well correlated with FMC, and the correlation between the indexes D (1450,) D (1940), R (1450i )/R (1940i ) and EWT were strong. The index A (1450)/A (1940) was tested to be a good indictor for evaluating plant water content, because there was strongest positive correlation between it and FMC than other indices. PMID:18853268

  1. Complexities in pyroxene compositions derived from absorption band centers: Examples from Apollo samples, HED meteorites, synthetic pure pyroxenes, and remote sensing data

    NASA Astrophysics Data System (ADS)

    Moriarty, D. P.; Pieters, C. M.

    2016-02-01

    We reexamine the relationship between pyroxene composition and near-infrared absorption bands, integrating measurements of diverse natural and synthetic samples. We test an algorithm (PLC) involving a two-part linear continuum removal and parabolic fits to the 1 and 2 μm bands—a computationally simple approach which can easily be automated and applied to remote sensing data. Employing a suite of synthetic pure pyroxenes, the PLC technique is shown to derive similar band centers to the modified Gaussian model. PLC analyses are extended to natural pyroxene-bearing materials, including (1) bulk lunar basalts and pyroxene separates, (2) diverse lunar soils, and (3) HED meteorites. For natural pyroxenes, the relationship between composition and absorption band center differs from that of synthetic pyroxenes. These differences arise from complexities inherent in natural materials such as exsolution, zoning, mixing, and space weathering. For these reasons, band center measurements of natural pyroxene-bearing materials are compositionally nonunique and could represent three distinct scenarios (1) pyroxene with a narrow compositional range, (2) complexly zoned pyroxene grains, or (3) a mixture of multiple pyroxene (or nonpyroxene) components. Therefore, a universal quantitative relationship between band centers and pyroxene composition cannot be uniquely derived for natural pyroxene-bearing materials without additional geologic context. Nevertheless, useful relative relationships between composition and band center persist in most cases. These relationships are used to interpret M3 data from the Humboldtianum Basin. Four distinct compositional units are identified (1) Mare Humboldtianum basalts, (2) distinct outer basalts, (3) low-Ca pyroxene-bearing materials, and (4) feldspathic materials.

  2. Uniting Ruthenium(II) and Platinum(II) Polypyridine Centers in Heteropolymetallic Complexes Giving Strong Two-Photon Absorption.

    PubMed

    Shi, Pengfei; Coe, Benjamin J; Sánchez, Sergio; Wang, Daqi; Tian, Yupeng; Nyk, Marcin; Samoc, Marek

    2015-12-01

    New trinuclear RuPt2 and heptanuclear RuPt6 complex salts are prepared by attaching Pt(II) 2,2':6',2"-terpyridine (tpy) moieties to Ru(II) 4,4':2',2":4",4"'-quaterpyridine (qpy) complexes. Characterization includes single crystal X-ray structures for both polymetallic species. The visible absorption bands are primarily due to Ru(II) → qpy metal-to-ligand charge-transfer (MLCT) transitions, according to time-dependent density functional theory (TD-DFT) calculations. These spectra change only slightly on Pt coordination, while the orange-red emission from the complexes shows corresponding small red-shifts, accompanied by decreases in intensity. Cubic molecular nonlinear optical behavior has been assessed by using Z-scan measurements. These reveal relatively high two-photon absorption (2PA) cross sections σ2, with maximal values of 301 GM at 834 nm (RuPt2) and 523 GM at 850 nm (RuPt6) when dissolved in methanol or acetone, respectively. Attaching Pt(II)(tpy) moieties triples or quadruples the 2PA activities when compared with the Ru(II)-based cores. PMID:26562721

  3. Infrared absorption spectroscopy with color-center lasers. Progress report, April 1 1982-February 15, 1983. [C/sub 2/H

    SciTech Connect

    Curl, R.F.

    1983-01-01

    In previous years, a color center laser spectrometer for the observation of the absorption spectra of small free radicals of importance in flames and discharges has been developed and several methods for increasing sensitivity explored. By combining magnetic rotation sensitivity enhancement with the long pathlengths obtainable with a multi-pass absorption cell very good sensitivity for free radicals (a detection limit of approx. 10/sup 9//cc for OH) has been achieved. Using this arrangement, the lowest electronic transition of the free radical C/sub 2/H has been observed for the first time in a DC glow discharge in a mixture of Ar and acetylene inside the multipass cell and one band assigned and analyzed. During the current grant year, the vibrational assignment of the C/sub 2/H bands has been completed. The difficult problem of calculating the lineshapes of these magnetic rotation transitions has been solved allowing the accurate (0.001 cm/sup -1/) determination of the linecenters. Rotational fitting has carried out, but is not yet in final form because of the presence of several perturbations which remain to be analyzed.

  4. Portable peak flow meters.

    PubMed

    McNaughton, J P

    1997-02-01

    There are several portable peak flow meters available. These instruments vary in construction and performance. Guidelines are recommended for minimum performance and testing of portable peak flow meters, with the aim of establishing a procedure for standardizing all peak flow meters. Future studies to clarify the usefulness of mechanical test apparatus and clinical trials of peak flow meters are also recommended. PMID:9098706

  5. Time-resolved absorption changes of the pheophytin Q{sub x} band in isolated photosystem II reaction centers at 7K : energy transfer and charge separation.

    SciTech Connect

    Greenfield, S. R.; Seibert, M.; Wasielewski, M. R.; Chemistry; LANL; NREL; Northwestern Univ.

    1999-09-30

    The pheophytin {alpha} Q{sub x} spectral region of the isolated photosystem II reaction center was investigated at 7 K using femtosecond transient absorption spectroscopy. At this temperature, uphill energy transfer, which greatly complicates the interpretation of the kinetics at or near room temperature, should be essentially shut off. Low-energy ({approx}100 nJ) pulses at 661 and 683 nm were used to excite the short-wavelength and long-wavelength sides of the composite Q{sub y} band, providing preferential excitation of the accessory pigment pool and P680, respectively. The data analysis uses a background subtraction technique developed earlier (Greenfield et al. J. Phys. Chem. B 1997, 101, 2251-2255) to remove the kinetic components of the data that are due to the large time-dependent changes in the background that are present in this spectral region. The instantaneous amplitude of the bleach of the pheophytin {alpha} Q{sub x} band with 683 nm excitation is roughly two-thirds of its final amplitude, providing strong evidence of a multimer description of the reaction center core. The subsequent growth of the bleach shows biphasic kinetics, similar to our earlier results at 278 K. The rate constant of the faster component is (5 ps){sup -1} for 683 nm excitation (a factor of almost two faster than at 278 K), and represents the intrinsic rate constant for charge separation. The bleach growth with 661 nm excitation is also biphasic; however, the faster component appears to be a composite of a (5 ps){sup -1} component corresponding to charge separation following subpicosecond energy transfer to the long-wavelength pigments and a roughly (22 ps){sup -1} component corresponding to charge separation limited by slow energy transfer. The combined quantum yield for these two energy transfer processes is near unity. For both excitation wavelengths, there is also a roughly (100 ps){sup -1} component to the bleach growth. Exposure to high excitation energies ({>=}1 {mu}J) at

  6. Time-resolved absorption changes of the pheophytin Q{sub x} band in isolated photosystem II reaction centers at 7 K: Energy transfer and charge separation

    SciTech Connect

    Greenfield, S.R.; Seibert, M.; Wasielewski, M.R.

    1999-09-30

    The pheophytin a Q{sub x} spectral region of the isolated photosystem II reaction center was investigated at 7 K using femtosecond transient absorption spectroscopy. At this temperature, uphill energy transfer, which greatly complicates the interpretation of the kinetics at or near room temperature, should be essentially shut off. Low-energy ({approximately}100 nJ) pulses at 661 and 683 nm were used to excite the short-wavelength and long-wavelength sides of the composite Q{sub y} band, providing preferential excitation of the accessory pigment pool and P680, respectively. The data analysis uses a background subtraction technique developed earlier (Greenfield et al. J. Phys. Chem. B 1997, 101, 2251--2255) to remove the kinetic components of the data that are due to the large time-dependent changes in the background that are present in this spectral region. The instantaneous amplitude of the bleach of the pheophytin a Q{sub x} band with 683 nm excitation is roughly two-thirds of its final amplitude, providing strong evidence of a multimer description of the reaction center core. The subsequent growth of the bleach shows biphasic kinetics, similar to the earlier results at 278 K. The rate constant of the faster component is (5 ps){sup {minus}1} for 683 nm excitation (a factor of almost two faster than at 278 K), and represents the intrinsic rate constant for charge separation. The bleach growth with 661 nm excitation is also biphasic; however, the faster component appears to be a composite of a (5 ps){sup {minus}1} component corresponding to charge separation following subpicosecond energy transfer to the long-wavelength pigments and a roughly (22 ps){sup {minus}1} component corresponding to charge separation limited by slow energy transfer. The combined quantum yield for these two energy transfer processes is near unity. For both excitation wavelengths, there is also a roughly (100 ps){sup {minus}1} component to the bleach growth. Exposure to high excitation

  7. Correlation between Active Center Structure and Enhanced Dioxygen Binding in Co(salen) Nanoparticles: Characterization by In Situ Infrared, Raman, and X-ray Absorption Spectroscopies

    SciTech Connect

    Johnson,C.; Long, B.; Nguyen, J.; Day, V.; Borovik, A.; Subramaniam, B.; Guzman, J.

    2008-01-01

    The structure and ligand environment of Co(salen) nanoparticles and unprocessed Co(salen) have been determined by the combined application of infrared, Raman, X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) spectroscopies, and X-ray diffraction (XRD) experiments before and during interaction with O2. The Co(salen) nanoparticles were prepared by the precipitation with compressed antisolvent (PCA) technique using commercially obtained Co(salen) [denoted as unprocessed Co(salen)] as the parent compound. The unprocessed Co(salen) particles exist as dimer species with a square-pyramidal coordination geometry that display no measurable O2 binding at room temperature. In sharp contrast, the Co(salen) nanoparticles show near-stoichiometric O2 adsorption, as demonstrated by microbalance gas binding experiments. The spectroscopy results indicate the presence of CoII centers with distorted tetrahedral geometry in the Co(salen) nanoparticles with no evidence of metallic Co clusters, confirmed by the lack of Co-Co contributions at bonding distances in the EXAFS spectra and the presence of characteristic features of CoII in the XANES spectra. The EXAFS data also indicate that there are on average two Co-N and two Co-O bonds with a distance of 1.81 {+-} 0.02 and 1.90 {+-} 0.02 Angstroms, respectively, consistent with typical metal salen structures. Upon O2 binding on the Co(salen) nanoparticles, the XANES results indicate oxidation of the CoII to CoIII, consistent with the vibrational data showing new bands associated with oxygen species bonded to Co centers and the increase in the oxygen coordination number from 1.8 to 2.9 in the EXAFS data. The results indicate that the enhanced O2 binding properties of Co(salen) nanoparticles are related to the unique distorted tetrahedral geometry, which is not observed in the unprocessed samples that contain mainly dimers with square planar geometry. The results presented here provide a

  8. Kinetic modeling of Fluorine vacancy/F center creation in LiF:Mg,Ti including vacancy-interstitial recombination: Evaluating the factors leading to the lack of supralinearity in the optical absorption F center concentration dose response

    NASA Astrophysics Data System (ADS)

    Eliyahu, I.; Horowitz, Y. S.; Oster, L.; Mardor, I.; Druzhyna, S.; Biderman, S.

    2015-01-01

    Kinetic model simulations of charge carrier transport following irradiation of LiF:Mg,Ti (TLD-100) including Fluorine vacancy/F center creation by the radiation and dose-dependent vacancy-interstitial recombination are presented which describe the experimentally measured linear/exponentially saturating optical absorption dose response of the electron trapping centers at 4.0 eV, 4.77 eV, 5.08 eV (F band) and 5.45 eV. Linear/exponentially saturating dose response is commonly observed for centers which are not created by the radiation. The creation of Fluorine vacancies by the radiation could therefore be expected to lead to a supralinear dose response of the F center before the onset of saturation. Nonetheless, the dose response is linear from 10 Gy to 500 Gy and can be fitted with a dose-filling constant β = 6.1 · 10-5 Gy-1 corresponding to a 5% and 25% decrease from linearity at 103 Gy and 5 · 103 Gy respectively. The model attempts to resolve a central question concerning the mechanisms leading to the linear/exponentially saturating dose response of the F band even though Fluorine vacancies are being continuously created during the irradiation. The electron-trapping characteristics of the created vacancies are assumed to differ somewhat from the vacancies originally present in un-irradiated samples due to differences in their immediate environment. Vacancy-interstitial recombination for separation distances less than a critical distance, dc is demonstrated to be significant for D > 500 Gy (dc = 36 Å) and is an important mechanism contributing to the F center saturation at high dose-levels. The kinetic model accurately simulates the experimentally observed F center dose response over the entire investigated dose range of 10-105 Gy under the following conditions: (i) The concentration of vacancies initially present is unexpectedly high at ∼1023 m-3, possibly due to the highly doped, non-crystalline and hot-pressed nature of the LiF:Mg,Ti samples. (ii) The

  9. Peak flow meter (image)

    MedlinePlus

    A peak flow meter is commonly used by a person with asthma to measure the amount of air that can be ... become narrow or blocked due to asthma, peak flow values will drop because the person cannot blow ...

  10. X-Ray Absorption Spectroscopic And Theoretical Studies on (L)(2)[Cu-2(S-2)N](2+) Complexes: Disulfide Versus Disulfide(Center Dot 1-) Bonding

    SciTech Connect

    Sarangi, R.; York, J.T.; Helton, M.E.; Fujisawa, K.; Karlin, K.D.; Tolman, W.B.; Hodgson, K.O.; Hedman, B.; Solomon, E.I.; /Stanford U., Chem. Dept. /SLAC, SSRL /Minnesota U. /Johns Hopkins U. /Tsukuba U.

    2009-04-30

    Cu K-, Cu L-, and S K-edge X-ray absorption spectroscopic (XAS) data have been combined with density functional theory (DFT) calculations on [{l_brace}(TMPA)Cu{r_brace}{sub 2}S{sub 2}](ClO{sub 4}){sub 2} (1), [{l_brace}Cu[HB(3,5-Pr{sub 2}{sup i}pz){sub 3}]{r_brace}{sub 2}(S{sub 2})] (2), and [{l_brace}(TMEDA)Cu{r_brace}{sub 2}(S{sub 2}){sub 2}](OTf){sub 2} (3) to obtain a quantitative description of their ground state wavefunctions. The Cu L-edge intensities give 63 and 37% Cu d-character in the ground state of 1 and 2, respectively, whereas the S K-pre-edge intensities reflect 20 and 48% S character in their ground states, respetively. These data indicate a more than 2-fold increase in the total disulfide bonding character in 2 relative to 1. The increase in the number of Cu?S bonds in 2 ({mu}-{eta}{sup 2}:{eta}{sup 2} S{sub 2}{sup 2-} bridge) compared to 1 ({mu}-{eta}{sup 1}:{eta}{sup 1} S{sub 2}{sup 2-} bridge) dominantly determines the large increase in covalency and Cu-disulfide bond strength in 2. Cu K- and L- and S K-pre-edge energy positions directly demonstrate the Cu{sup II}/(S{sub 2}{sup -}){sub 2} nature of 3. The two disulfide({center_dot}1?)'s in 3 undergo strong bonding interactions that destabilize the resultant filled antibonding {pi}* orbitals of the (S{sub 2}{sup -}){sub 2} fragment relative to the Cu 3d levels. This leads to an inverted bonding scheme in 3 with dominantly ligand-based holes in its ground state, consistent with its description as a dicopper(II)-bis-disulfide({center_dot}1?) complex.

  11. Children’s Phthalate Intakes and Resultant Cumulative Exposures Estimated from Urine Compared with Estimates from Dust Ingestion, Inhalation and Dermal Absorption in Their Homes and Daycare Centers

    PubMed Central

    Bekö, Gabriel; Weschler, Charles J.; Langer, Sarka; Callesen, Michael; Toftum, Jørn; Clausen, Geo

    2013-01-01

    Total daily intakes of diethyl phthalate (DEP), di(n-butyl) phthalate (DnBP), di(isobutyl) phthalate (DiBP), butyl benzyl phthalate (BBzP) and di(2-ethylhexyl) phthalate (DEHP) were calculated from phthalate metabolite levels measured in the urine of 431 Danish children between 3 and 6 years of age. For each child the intake attributable to exposures in the indoor environment via dust ingestion, inhalation and dermal absorption were estimated from the phthalate levels in the dust collected from the child’s home and daycare center. Based on the urine samples, DEHP had the highest total daily intake (median: 4.42 µg/d/kg-bw) and BBzP the lowest (median: 0.49 µg/d/kg-bw). For DEP, DnBP and DiBP, exposures to air and dust in the indoor environment accounted for approximately 100%, 15% and 50% of the total intake, respectively, with dermal absorption from the gas-phase being the major exposure pathway. More than 90% of the total intake of BBzP and DEHP came from sources other than indoor air and dust. Daily intake of DnBP and DiBP from all exposure pathways, based on levels of metabolites in urine samples, exceeded the Tolerable Daily Intake (TDI) for 22 and 23 children, respectively. Indoor exposures resulted in an average daily DiBP intake that exceeded the TDI for 14 children. Using the concept of relative cumulative Tolerable Daily Intake (TDIcum), which is applicable for phthalates that have established TDIs based on the same health endpoint, we examined the cumulative total exposure to DnBP, DiBP and DEHP from all pathways; it exceeded the tolerable levels for 30% of the children. From the three indoor pathways alone, several children had a cumulative intake that exceeded TDIcum. Exposures to phthalates present in the air and dust indoors meaningfully contribute to a child’s total intake of certain phthalates. Such exposures, by themselves, may lead to intakes exceeding current limit values. PMID:23626820

  12. Peak Experience Project

    ERIC Educational Resources Information Center

    Scott, Daniel G.; Evans, Jessica

    2010-01-01

    This paper emerges from the continued analysis of data collected in a series of international studies concerning Childhood Peak Experiences (CPEs) based on developments in understanding peak experiences in Maslow's hierarchy of needs initiated by Dr Edward Hoffman. Bridging from the series of studies, Canadian researchers explore collected…

  13. Optical properties of radiation defect centers involving single and paired Mn{sup 2+} centers in CaF{sub 2}:Mn

    SciTech Connect

    Chakrabarti, K.; Sharma, J.; Mathur, V.K.; Barkyoumb, J.H.

    1995-06-15

    Optical evidence of paired Mn{sup 2+} centers has been observed in CaF{sub 2}:Mn by time-resolved laser spectroscopy. The paired Mn{sup 2+} center is associated with a peak shift of the Mn{sup 2+} emisssion towards longer wavelength and a faster component of decay of 500 {mu}s along with a slow decay of 48 ms due to a single Mn{sup 2+} ion. It appear that this center forms a Mn{sup 2+}-{ital F}-center-Mn{sup 2+} complex when the material is {gamma} irradiated. This complex is associated with a thermoluminescence peak near 360 {degree}C and an optical-absorption band near 300 nm. A conversion from a Mn{sup 2+}-{ital F}-center-Mn{sup 2+} complex to an {ital F}-center-Mn{sup 2+} complex is observed in phototransferred thermoluminescence and in photobleached optical-absorption spectra.

  14. Solar investigation at Terskol Peak

    NASA Astrophysics Data System (ADS)

    Burlov-Vasiljev, K. A.; Vasiljeva, I. E.

    2003-04-01

    During 1980--1990 regular observations of the solar disk spectrum and active solar structures were carried out with SEF-1 and ATsU-26 telescopes at Terskol Peak in the framework of the program ``Energy distribution in the solar spectrum in absolute energy units''. In order to refine the fine structure of telluric lines, observations with ATsU-26 telescope were carried out in parallel. This telescope was also used for the investigation of the solar active structures. In this paper the observational technique is described. The obtained results and energy distribution in the solar disk center in absolute energy units are presented.

  15. Peak power ratio generator

    DOEpatents

    Moyer, R.D.

    A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

  16. Peak power ratio generator

    DOEpatents

    Moyer, Robert D.

    1985-01-01

    A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

  17. Ultrafast transient absorption studies on photosystem I reaction centers from Chlamydomonas reinhardtii. 2: mutations near the P700 reaction center chlorophylls provide new insight into the nature of the primary electron donor.

    PubMed

    Holzwarth, Alfred R; Müller, Marc G; Niklas, Jens; Lubitz, Wolfgang

    2006-01-15

    The energy transfer and charge separation kinetics in several core Photosystem I particles of Chlamydomonas reinhardtii with point mutations around the PA and PB reaction center chlorophylls (Chls) have been studied using ultrafast transient absorption spectroscopy in the femtosecond to nanosecond time range to characterize the influence on the early electron transfer processes. The data have been analyzed in terms of kinetic compartment models. The adequate description of the transient absorption kinetics requires three different radical pairs in the time range up to approximately 100 ps. Also a charge recombination process from the first radical pair back to the excited state is present in all the mutants, as already shown previously for the wild-type (Müller, M. G., J. Niklas, W. Lubitz, and A. R. Holzwarth. 2003. Biophys. J. 85:3899-3922; and Holzwarth, A. R., M. G. Müller, J. Niklas, and W. Lubitz. 2005. J. Phys. Chem. B. 109:5903-59115). In all mutants, the primary charge separation occurs with the same effective rate constant within the error limits as in the wild-type (>350 ns(-1)), which implies an intrinsic rate constant of charge separation of <1 ps(-1). The rate constant of the secondary electron transfer process is slowed down by a factor of approximately 2 in the mutant B-H656C, which lacks the ligand to the central metal of Chl PB. For the mutant A-T739V, which breaks the hydrogen bond to the keto carbonyl of Chl PA, only a slight slowing down of the secondary electron transfer is observed. Finally for mutant A-W679A, which has the Trp near the PA Chl replaced, either no pronounced effect or, at best, a slight increase on the secondary electron transfer rate constants is observed. The effective charge recombination rate constant is modified in all mutants to some extent, with the strongest effect observed in mutant B-H656C. Our data strongly suggest that the Chls of the PA and PB pair, constituting what is traditionally called the "primary electron

  18. Peak Oil, Peak Coal and Climate Change

    NASA Astrophysics Data System (ADS)

    Murray, J. W.

    2009-05-01

    Research on future climate change is driven by the family of scenarios developed for the IPCC assessment reports. These scenarios create projections of future energy demand using different story lines consisting of government policies, population projections, and economic models. None of these scenarios consider resources to be limiting. In many of these scenarios oil production is still increasing to 2100. Resource limitation (in a geological sense) is a real possibility that needs more serious consideration. The concept of 'Peak Oil' has been discussed since M. King Hubbert proposed in 1956 that US oil production would peak in 1970. His prediction was accurate. This concept is about production rate not reserves. For many oil producing countries (and all OPEC countries) reserves are closely guarded state secrets and appear to be overstated. Claims that the reserves are 'proven' cannot be independently verified. Hubbert's Linearization Model can be used to predict when half the ultimate oil will be produced and what the ultimate total cumulative production (Qt) will be. US oil production can be used as an example. This conceptual model shows that 90% of the ultimate US oil production (Qt = 225 billion barrels) will have occurred by 2011. This approach can then be used to suggest that total global production will be about 2200 billion barrels and that the half way point will be reached by about 2010. This amount is about 5 to 7 times less than assumed by the IPCC scenarios. The decline of Non-OPEC oil production appears to have started in 2004. Of the OPEC countries, only Saudi Arabia may have spare capacity, but even that is uncertain, because of lack of data transparency. The concept of 'Peak Coal' is more controversial, but even the US National Academy Report in 2007 concluded only a small fraction of previously estimated reserves in the US are actually minable reserves and that US reserves should be reassessed using modern methods. British coal production can be

  19. Pressure dependence of Se absorption lines in AlSb

    SciTech Connect

    Hsu, L. |; Haller, E.E.; Ramdas, A.K.

    1996-09-01

    Using far infrared absorption spectroscopy, the authors have investigated electronic transition spectra of Se donors in AlSb as a function of hydrostatic pressure. At least two distinct ground to bound excited state transition lines, which depend quadratically on the pressure, can be seen. At pressures between 30 and 50 kbar, evidence of an anti-crossing between one of the electronic transitions and a peak which they attribute to the 2 zone center LO phonon mode can be seen.

  20. Make peak flow a habit!

    MedlinePlus

    Asthma - make peak flow a habit; Reactive airway disease - peak flow; Bronchial asthma - peak flow ... your airways are narrowed and blocked due to asthma, your peak flow values drop. You can check ...

  1. Hale Central Peak

    NASA Technical Reports Server (NTRS)

    2004-01-01

    19 September 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows some of the mountains that make up the central peak region of Hale Crater, located near 35.8oS, 36.5oW. Dark, smooth-surfaced sand dunes are seen to be climbing up the mountainous slopes. The central peak of a crater consists of rock brought up during the impact from below the crater floor. This autumn image is illuminated from the upper left and covers an area approximately 3 km (1.9 mi) across.

  2. Impact Crater with Peak

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 14 June 2002) The Science This THEMIS visible image shows a classic example of a martian impact crater with a central peak. Central peaks are common in large, fresh craters on both Mars and the Moon. This peak formed during the extremely high-energy impact cratering event. In many martian craters the central peak has been either eroded or buried by later sedimentary processes, so the presence of a peak in this crater indicates that the crater is relatively young and has experienced little degradation. Observations of large craters on the Earth and the Moon, as well as computer modeling of the impact process, show that the central peak contains material brought from deep beneath the surface. The material exposed in these peaks will provide an excellent opportunity to study the composition of the martian interior using THEMIS multi-spectral infrared observations. The ejecta material around the crater can is well preserved, again indicating relatively little modification of this landform since its initial creation. The inner walls of this approximately 18 km diameter crater show complex slumping that likely occurred during the impact event. Since that time there has been some downslope movement of material to form the small chutes and gullies that can be seen on the inner crater wall. Small (50-100 m) mega-ripples composed of mobile material can be seen on the floor of the crater. Much of this material may have come from the walls of the crater itself, or may have been blown into the crater by the wind. The Story When a meteor smacked into the surface of Mars with extremely high energy, pow! Not only did it punch an 11-mile-wide crater in the smoother terrain, it created a central peak in the middle of the crater. This peak forms kind of on the 'rebound.' You can see this same effect if you drop a single drop of milk into a glass of milk. With craters, in the heat and fury of the impact, some of the land material can even liquefy. Central peaks like the one

  3. PEAK READING VOLTMETER

    DOEpatents

    Dyer, A.L.

    1958-07-29

    An improvement in peak reading voltmeters is described, which provides for storing an electrical charge representative of the magnitude of a transient voltage pulse and thereafter measuring the stored charge, drawing oniy negligible energy from the storage element. The incoming voltage is rectified and stored in a condenser. The voltage of the capacitor is applied across a piezoelectric crystal between two parallel plates. Amy change in the voltage of the capacitor is reflected in a change in the dielectric constant of the crystal and the capacitance between a second pair of plates affixed to the crystal is altered. The latter capacitor forms part of the frequency determlning circuit of an oscillator and means is provided for indicating the frequency deviation which is a measure of the peak voltage applied to the voltmeter.

  4. INDIAN PEAKS WILDERNESS, COLORADO.

    USGS Publications Warehouse

    Pearson, Robert C.; Speltz, Charles N.

    1984-01-01

    The Indian Peaks Wilderness northwest of Denver is partly within the Colorado Mineral Belt, and the southeast part of it contains all the geologic characteristics associated with the several nearby mining districts. Two deposits have demonstrated mineral resources, one of copper and the other of uranium; both are surrounded by areas with probable potential. Two other areas have probable resource potential for copper, gold, and possibly molydenum. Detailed gravity and magnetic studies in the southeast part of the Indian Peaks Wilderness might detect in the subsurface igneous bodies that may be mineralized. Physical exploration such as drilling would be necessary to determine more precisely the copper resources at the Roaring Fork locality and uranium resources at Wheeler Basin.

  5. Peak of Desire

    PubMed Central

    Huang, Julie Y.; Bargh, John A.

    2008-01-01

    In three studies, we explore the existence of an evolved sensitivity to the peak as consistent with the evolutionary origins of many of our basic preferences. Activating the evolved motive of mating activates related adaptive mechanisms, including a general sensitivity to cues of growth and decay associated with determining mate value in human courtship. We establish that priming the mating goal also activates as well an evaluative bias that influences how people evaluate cues of growth. Specifically, living kinds that are immature or past their prime are devalued, whereas living kinds at their peak become increasingly valued. Study 1 establishes this goal-driven effect for human stimuli indirectly related to the mating goal. Studies 2 and 3 establish that the evaluative bias produced by the active mating goal extends to living kinds but not artifacts. PMID:18578847

  6. PEAK LIMITING AMPLIFIER

    DOEpatents

    Goldsworthy, W.W.; Robinson, J.B.

    1959-03-31

    A peak voltage amplitude limiting system adapted for use with a cascade type amplifier is described. In its detailed aspects, the invention includes an amplifier having at least a first triode tube and a second triode tube, the cathode of the second tube being connected to the anode of the first tube. A peak limiter triode tube has its control grid coupled to thc anode of the second tube and its anode connected to the cathode of the second tube. The operation of the limiter is controlled by a bias voltage source connected to the control grid of the limiter tube and the output of the system is taken from the anode of the second tube.

  7. DIAMOND PEAK WILDERNESS, OREGON.

    USGS Publications Warehouse

    Sherrod, David R.; Moyle, Phillip R.

    1984-01-01

    No metallic mineral resources were identified during a mineral survey of the Diamond Peak Wilderness in Oregon. Cinder cones within the wilderness contain substantial cinder resources, but similar deposits that are more accessible occur outside the wilderness. The area could have geothermal resources, but available data are insufficient to evaluate their potential. Several deep holes could be drilled in areas of the High Cascades outside the wilderness, from which extrapolations of the geothermal potential of the several Cascade wilderness could be made.

  8. ABSORPTION ANALYZER

    DOEpatents

    Brooksbank, W.A. Jr.; Leddicotte, G.W.; Strain, J.E.; Hendon, H.H. Jr.

    1961-11-14

    A means was developed for continuously computing and indicating the isotopic assay of a process solution and for automatically controlling the process output of isotope separation equipment to provide a continuous output of the desired isotopic ratio. A counter tube is surrounded with a sample to be analyzed so that the tube is exactly in the center of the sample. A source of fast neutrons is provided and is spaced from the sample. The neutrons from the source are thermalized by causing them to pass through a neutron moderator, and the neutrons are allowed to diffuse radially through the sample to actuate the counter. A reference counter in a known sample of pure solvent is also actuated by the thermal neutrons from the neutron source. The number of neutrons which actuate the detectors is a function of a concentration of the elements in solution and their neutron absorption cross sections. The pulses produced by the detectors responsive to each neu tron passing therethrough are amplified and counted. The respective times required to accumulate a selected number of counts are measured by associated timing devices. The concentration of a particular element in solution may be determined by utilizing the following relation: T2/Ti = BCR, where B is a constant proportional to the absorption cross sections, T2 is the time of count collection for the unknown solution, Ti is the time of count collection for the pure solvent, R is the isotopic ratlo, and C is the molar concentration of the element to be determined. Knowing the slope constant B for any element and when the chemical concentration is known, the isotopic concentration may be readily determined, and conversely when the isotopic ratio is known, the chemical concentrations may be determined. (AEC)

  9. Kitt Peak speckle camera

    NASA Technical Reports Server (NTRS)

    Breckinridge, J. B.; Mcalister, H. A.; Robinson, W. G.

    1979-01-01

    The speckle camera in regular use at Kitt Peak National Observatory since 1974 is described in detail. The design of the atmospheric dispersion compensation prisms, the use of film as a recording medium, the accuracy of double star measurements, and the next generation speckle camera are discussed. Photographs of double star speckle patterns with separations from 1.4 sec of arc to 4.7 sec of arc are shown to illustrate the quality of image formation with this camera, the effects of seeing on the patterns, and to illustrate the isoplanatic patch of the atmosphere.

  10. X-ray absorption spectroscopic studies of the diiron center in methane monooxygenase in the presence of substrate and the coupling protein of the enzyme system

    SciTech Connect

    DeWitt, J.G.; Rosenzweig, A.C.; Salifoglou, A.

    1995-05-10

    The interaction among the hydroxylase component of methane monooxygenase (MMO) from Methylococcus capsulatus (Bath), the coupling protein of the MMO enzyme system (component B), and substrate has been investigated by using Fe K-edge X-ray absorption spectroscopy (XAS). Fe K-edge extended X-ray absorption fine structure (EXAFS) studies of the semimet form of the hydroxylase in the presence of the coupling protein, 1-bromo-1-propene, and both the coupling protein and 1-bromo-1-propene revealed small differences in the appearance of the EXAFS above k = 8 {Angstrom}{sup {minus}1} as compared to the noncomplexed hydroxylase. No dramatic change in the Fe coordination was seen in fits to the data. The average first shell Fe-O/N distance for the complexed forms of the semimet hydroxylase ranged between 2.06 and 2.08 {Angstrom}, which is comparable to the distance found for the noncomplexed form, 2.06-2.09 {Angstrom}. Although the average first shell coordination was similar for all samples, a difference was seen in the distribution of long vs short distance contributions to the first shell coordination sphere for samples with component B present. This difference was accompanied by a small but consistent decrease in the Fe-Fe distance of the B-complexed hydroxylase samples, from 3.42 to 3.39 {angstrom}.

  11. Make peak flow a habit!

    MedlinePlus

    Checking your peak flow is one of the best ways to control your asthma and to keep it from getting worse. Asthma attacks ... Most times, they build slowly. Checking your peak flow can tell you if an attack is coming, ...

  12. Cholesterol absorption.

    PubMed

    Ostlund, Richard E

    2002-03-01

    Cholesterol absorption is a key regulatory point in human lipid metabolism because it determines the amount of endogenous biliary as well as dietary cholesterol that is retained, thereby influencing whole body cholesterol balance. Plant sterols (phytosterols) and the drug ezetimibe reduce cholesterol absorption and low-density lipoprotein cholesterol in clinical trials, complementing the statin drugs, which inhibit cholesterol biosynthesis. The mechanism of cholesterol absorption is not completely known but involves the genes ABC1, ABCG5, and ABCG8, which are members of the ATP-binding cassette protein family and appear to remove unwanted cholesterol and phytosterols from the enterocyte. ABC1 is upregulated by the liver X (LXR) and retinoid X (RXR) nuclear receptors. Acylcholesterol acytransferase-2 is an intestinal enzyme that esterifies absorbed cholesterol and increases cholesterol absorption when dietary intake is high. New clinical treatments based on better understanding of absorption physiology are likely to substantially improve clinical cholesterol management in the future. PMID:17033296

  13. Decoupling approximation design using the peak to peak gain

    NASA Astrophysics Data System (ADS)

    Sultan, Cornel

    2013-04-01

    Linear system design for accurate decoupling approximation is examined using the peak to peak gain of the error system. The design problem consists in finding values of system parameters to ensure that this gain is small. For this purpose a computationally inexpensive upper bound on the peak to peak gain, namely the star norm, is minimized using a stochastic method. Examples of the methodology's application to tensegrity structures design are presented. Connections between the accuracy of the approximation, the damping matrix, and the natural frequencies of the system are examined, as well as decoupling in the context of open and closed loop control.

  14. Tectonics, Climate and Earth's highest peaks

    NASA Astrophysics Data System (ADS)

    Robl, Jörg; Prasicek, Günther; Hergarten, Stefan

    2016-04-01

    of about 5000 m suggesting that the topography is fairly well supported by local isostasy. In contrast, the highest peaks of the India-Asia collision zone seam the plateau rim and exceed the surface elevation predicted by crustal thickness and local isostasy. They are likely supported by the lithospheric strength of the northern and southern foreland basins and further uplifted by spatially variable unloading of the orogen due to major rivers and glaciers. Peak altitude, landscape dissection and the long-term impact of erosion on crustal thickness increase from the center of the Tibetan Plateau to the rim. However, we found evidence for a similar trend on a global scale from mid- to high-latitude orogens. Towards high latitudes, peaks of similar height are characterized by a more dissected landscape and supported by a thinner crust compared to mid-latitude mountain ranges. This however, would imply that the recent glacial period has already influenced orogens on their crustal level. We propose that long-term glacial erosion in high latitudes may have already thinned the orogenic crust and conclude that (a) over-thickened crust in zones of plate convergence can buffer intense erosion and maintain high mountain topography over millions of years even in heavily glaciated orogens, (b) high peaks may persist or may even be uplifted due to glacial erosion and (c) glacial erosion limiting mountain topography may NOT work as simple as a buzz-saw applied to fluvial topography supported by a thick mountain root.

  15. First Spectroscopic Identification of Massive Young Stellar Objects in the Galactic Center

    NASA Technical Reports Server (NTRS)

    An, Deokkeun; Ramirez, V.; Sellgren, Kris; Arendt, Richard G.; Boogert, A. C.; Schultheis, Mathias; Stolovy, Susan R.; Cotera, Angela S.; Robitaille, Thomas P.; Smith, Howard A.

    2009-01-01

    We report the detection of several molecular gas-phase and ice absorption features in three photometrically-selected young stellar object (YSO) candidates in the central 280 pc of the Milky Way. Our spectra, obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope, reveal gas-phase absorption from CO2 (15.0 microns), C2H2 (13.7 microns) and HCN (14.0 microns). We attribute this absorption to warm, dense gas in massive YSOs. We also detect strong and broad 15 microns CO2 ice absorption features, with a remarkable double-peaked structure. The prominent long-wavelength peak is due to CH3OH-rich ice grains, and is similar to those found in other known massive YSOs. Our IRS observa.tions demonstra.te the youth of these objects, and provide the first spectroscopic identification of massive YSOs in the Galactic Center.

  16. Rich magneto-absorption spectra of AAB-stacked trilayer graphene.

    PubMed

    Do, Thi-Nga; Shih, Po-Hsin; Chang, Cheng-Peng; Lin, Chiun-Yan; Lin, Ming-Fa

    2016-06-29

    A generalized tight-binding model is developed to investigate the feature-rich magneto-optical properties of AAB-stacked trilayer graphene. Three intragroup and six intergroup inter-Landau-level (inter-LL) optical excitations largely enrich magneto-absorption peaks. In general, the former are much higher than the latter, depending on the phases and amplitudes of LL wavefunctions. The absorption spectra exhibit single- or twin-peak structures which are determined by quantum modes, LL energy spectra and Fermion distribution. The splitting LLs, with different localization centers (2/6 and 4/6 positions in a unit cell), can generate very distinct absorption spectra. There exist extra single peaks because of LL anti-crossings. AAB, AAA, ABA, and ABC stackings considerably differ from one another in terms of the inter-LL category, frequency, intensity, and structure of absorption peaks. The main characteristics of LL wavefunctions and energy spectra and the Fermi-Dirac function are responsible for the configuration-enriched magneto-optical spectra. PMID:27305856

  17. Robust detection of peak signals for lateral flow immunoassays

    NASA Astrophysics Data System (ADS)

    Kim, Jongwon; Kim, Jong Dae; Nahm, Kie Bong; Choi, Eui Yul; Lee, Geumyoung

    2011-02-01

    Template matching method is presented to identify the peaks from the scanned signals of lateral flow immunoassay strips. The template is composed of two pulses separated by the distance of the control and the target ligand line in the assay, and is convolved with the scanned signal to deliver the maximum at the center of the two peaks. The peak regions were identified with the predefined distances from the center. Glycosylated haemoglobin immunoassay strips and fluorescent strip readers from Boditechmed Inc. were tested to estimate the lot and reader variations of the concentration measurands. The results showed the robustness of the propose method.

  18. Optical absorption of silicon nanowires

    SciTech Connect

    Xu, T.; Lambert, Y.; Krzeminski, C.; Grandidier, B.; Stievenard, D.; Leveque, G.; Akjouj, A.; Pennec, Y.; Djafari-Rouhani, B.

    2012-08-01

    We report on simulations and measurements of the optical absorption of silicon nanowires (NWs) versus their diameter. We first address the simulation of the optical absorption based on two different theoretical methods: the first one, based on the Green function formalism, is useful to calculate the scattering and absorption properties of a single or a finite set of NWs. The second one, based on the finite difference time domain (FDTD) method, is well-adapted to deal with a periodic set of NWs. In both cases, an increase of the onset energy for the absorption is found with increasing diameter. Such effect is experimentally illustrated, when photoconductivity measurements are performed on single tapered Si nanowires connected between a set of several electrodes. An increase of the nanowire diameter reveals a spectral shift of the photocurrent intensity peak towards lower photon energies that allow to tune the absorption onset from the ultraviolet radiations to the visible light spectrum.

  19. Ultraviolet absorption spectrum of HOCl

    NASA Technical Reports Server (NTRS)

    Burkholder, James B.

    1993-01-01

    The room temperature UV absorption spectrum of HOCl was measured over the wavelength range 200 to 380 nm with a diode array spectrometer. The absorption spectrum was identified from UV absorption spectra recorded following UV photolysis of equilibrium mixtures of Cl2O/H2O/HOCl. The HOCl spectrum is continuous with a maximum at 242 nm and a secondary peak at 304 nm. The measured absorption cross section at 242 nm was (2.1 +/- 0.3) x 10 exp -19/sq cm (2 sigma error limits). These results are in excellent agreement with the work of Knauth et al. (1979) but in poor agreement with the more recent measurements of Mishalanie et al. (1986) and Permien et al. (1988). An HOCl nu2 infrared band intensity of 230 +/- 35/sq cm atm was determined based on this UV absorption cross section. The present results are compared with these previous measurements and the discrepancies are discussed.

  20. KrF- and ArF-excimer-laser-induced absorption in silica glasses produced by melting synthetic silica powder

    SciTech Connect

    Kuzuu, Nobu; Sasaki, Toshiya; Kojima, Tatsuya; Tanaka, Jun-ichiro; Nakamura, Takayuki; Horikoshi, Hideharu

    2013-07-07

    KrF- and ArF-excimer-laser-induced absorption of silica glasses produced by electric melting and flame fusion of synthetic silica powder were investigated. The growth of KrF-laser-induced absorption was more gradual than that of ArF-laser-induced absorption. Induced absorption spectra exhibited a peak at about 5.8 eV, of which the position and width differed slightly among samples and laser species. Widths of ArF-laser-induced absorption spectra were wider than those of KrF-laser-induced spectra. KrF-laser-induced absorption is reproducible by two Gaussian absorption bands peaking at 5.80 eV with full width at half maximum (FWHM) of 0.62 eV and at 6.50 eV with FWHM of 0.74 eV. For reproduction of ArF-laser-induced absorption, Gaussian bands at 5.41 eV with FWHM of 0.62 eV was necessary in addition to components used for reproducing KrF-laser-induced absorption. Based on the discussion of the change of defect structures evaluated from change of absorption components, we proposed that the precursor of the 5.8-eV band ascribed to E Prime center ({identical_to}Si{center_dot}) is {identical_to}Si-H HO-Si{identical_to} structures formed by the reaction between strained Si-O-Si bonds and interstitial H{sub 2} molecules during the irradiation.

  1. How to use your peak flow meter

    MedlinePlus

    Peak flow meter - how to use; Asthma - peak flow meter; Reactive airway disease - peak flow meter; Bronchial asthma - peak flow meter ... your airways are narrowed and blocked due to asthma, your peak flow values drop. You can check ...

  2. Peak Wind Tool for General Forecasting

    NASA Technical Reports Server (NTRS)

    Barrett, Joe H., III; Short, David

    2008-01-01

    This report describes work done by the Applied Meteorology Unit (AMU) in predicting peak winds at Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The 45th Weather Squadron requested the AMU develop a tool to help them forecast the speed and timing of the daily peak and average wind, from the surface to 300 ft on KSC/CCAFS during the cool season. Based on observations from the KSC/CCAFS wind tower network , Shuttle Landing Facility (SLF) surface observations, and CCAFS sounding s from the cool season months of October 2002 to February 2007, the AMU created mul tiple linear regression equations to predict the timing and speed of the daily peak wind speed, as well as the background average wind speed. Several possible predictors were evaluated, including persistence , the temperature inversion depth and strength, wind speed at the top of the inversion, wind gust factor (ratio of peak wind speed to average wind speed), synoptic weather pattern, occurrence of precipitation at the SLF, and strongest wind in the lowest 3000 ft, 4000 ft, or 5000 ft.

  3. Visible absorption spectrum of liquid ethylene

    PubMed Central

    Nelson, Edward T.; Patel, C. Kumar N.

    1981-01-01

    The visible absorption spectrum of liquid ethylene at ≈ 108 K from 5500 Å to 7200 Å was measured by using a pulsed tunable dye laser, immersed-transducer, gated-detection opto-acoustic spectroscopy technique. The absorption features show the strongest band with an absorption coefficient of ≈2 × 10-2 cm-1 and the weakest band with an absorption coefficient of ≈1 × 10-4 cm-1. Proposed assignments of the observed absorption peaks involve combinations of overtones of local and normal modes of vibration of ethylene. PMID:16592978

  4. An accelerated line-by-line option for MODTRAN combining on-the-fly generation of line center absorption within 0.1 cm-1 bins and pre-computed line tails

    NASA Astrophysics Data System (ADS)

    Berk, Alexander; Conforti, Patrick; Hawes, Fred

    2015-05-01

    A Line-By-Line (LBL) option is being developed for MODTRAN6. The motivation for this development is two-fold. Firstly, when MODTRAN is validated against an independent LBL model, it is difficult to isolate the source of discrepancies. One must verify consistency between pressure, temperature and density profiles, between column density calculations, between continuum and particulate data, between spectral convolution methods, and more. Introducing a LBL option directly within MODTRAN will insure common elements for all calculations other than those used to compute molecular transmittances. The second motivation for the LBL upgrade is that it will enable users to compute high spectral resolution transmittances and radiances for the full range of current MODTRAN applications. In particular, introducing the LBL feature into MODTRAN will enable first-principle calculations of scattered radiances, an option that is often not readily available with LBL models. MODTRAN will compute LBL transmittances within one 0.1 cm-1 spectral bin at a time, marching through the full requested band pass. The LBL algorithm will use the highly accurate, pressure- and temperature-dependent MODTRAN Padé approximant fits of the contribution from line tails to define the absorption from all molecular transitions centered more than 0.05 cm-1 from each 0.1 cm-1 spectral bin. The beauty of this approach is that the on-the-fly computations for each 0.1 cm-1 bin will only require explicit LBL summing of transitions centered within a 0.2 cm-1 spectral region. That is, the contribution from the more distant lines will be pre-computed via the Padé approximants. The status of the LBL effort will be presented. This will include initial thermal and solar radiance calculations, validation calculations, and self-validations of the MODTRAN band model against its own LBL calculations.

  5. Two classes of speculative peaks

    NASA Astrophysics Data System (ADS)

    Roehner, Bertrand M.

    2001-10-01

    Speculation not only occurs in financial markets but also in numerous other markets, e.g. commodities, real estate, collectibles, and so on. Such speculative movements result in price peaks which share many common characteristics: same order of magnitude of duration with respect to amplitude, same shape (the so-called sharp-peak pattern). Such similarities suggest (at least as a first approximation) a common speculative behavior. However, a closer examination shows that in fact there are (at least) two distinct classes of speculative peaks. For the first, referred to as class U, (i) the amplitude of the peak is negatively correlated with the price at the start of the peak (ii) the ensemble coefficient of variation exhibits a trough. Opposite results are observed for the second class that we refer to as class S. Once these empirical observations have been made we try to understand how they should be interpreted. First, we show that the two properties are in fact related in the sense that the second is a consequence of the first. Secondly, by listing a number of cases belonging to each class we observe that the markets in the S-class offer collection of items from which investors can select those they prefer. On the contrary, U-markets consist of undifferentiated products for which a selection cannot be made in the same way. All prices considered in the paper are real (i.e., deflated) prices.

  6. Hubbert's Peak: A Physicist's View

    NASA Astrophysics Data System (ADS)

    McDonald, Richard

    2011-11-01

    Oil and its by-products, as used in manufacturing, agriculture, and transportation, are the lifeblood of today's 7 billion-person population and our 65T world economy. Despite this importance, estimates of future oil production seem dominated by wishful thinking rather than quantitative analysis. Better studies are needed. In 1956, Dr. M.King Hubbert proposed a theory of resource production and applied it successfully to predict peak U.S. oil production in 1970. Thus, the peak of oil production is referred to as ``Hubbert's Peak.'' Prof. Al Bartlett extended this work in publications and lectures on population and oil. Both Hubbert and Bartlett place peak world oil production at a similar time, essentially now. This paper extends this line of work to include analyses of individual countries, inclusion of multiple Gaussian peaks, and analysis of reserves data. While this is not strictly a predictive theory, we will demonstrate a ``closed'' story connecting production, oil-in-place, and reserves. This gives us the ``most likely'' estimate of future oil availability. Finally, we will comment on synthetic oil and the possibility of carbon-neutral synthetic oil for a sustainable future.

  7. Absorption spectra of graphene nanoribbons in a composite magnetic field

    NASA Astrophysics Data System (ADS)

    Li, T. S.; Wu, M. F.; Hsieh, C. T.

    2015-10-01

    The low-frequency optical absorption properties of graphene nanoribbons in a composite magnetic field are investigated by using the gradient approximation. The spectral function exhibits symmetric delta-function like prominent peaks structure in a uniform magnetic field, and changes to asymmetric square-root divergent peaks structure when subjecting to a composite field. These asymmetric divergent peaks can be further classified into principal and secondary peaks. The spectral intensity and frequency of the absorption peaks depend sensitively on the strength and modulation period of the composite field. The transition channels of the absorption peaks are also analyzed. There exists an optical selection rule which is caused by the orthogonal properties of the sublattice wave functions. The evolution of the spectral frequency of the absorption peaks with the field strength is explored.

  8. Stochastic acceleration in peaked spectrum

    SciTech Connect

    Zasenko, V.; Zagorodny, A.; Weiland, J.

    2005-06-15

    Diffusion in velocity space of test particles undergoing external random electric fields with spectra varying from low intensive and broad to high intensive and narrow (peaked) is considered. It is shown that to achieve consistency between simulation and prediction of the microscopic model, which is reduced to Fokker-Planck-type equation, it is necessary, in the case of peaked spectrum, to account for temporal variation of diffusion coefficient occurring in the early stage. An analytical approximation for the solution of the Fokker-Planck equation with a time and velocity dependent diffusion coefficients is proposed.

  9. Peak finding using biorthogonal wavelets

    SciTech Connect

    Tan, C.Y.

    2000-02-01

    The authors show in this paper how they can find the peaks in the input data if the underlying signal is a sum of Lorentzians. In order to project the data into a space of Lorentzian like functions, they show explicitly the construction of scaling functions which look like Lorentzians. From this construction, they can calculate the biorthogonal filter coefficients for both the analysis and synthesis functions. They then compare their biorthogonal wavelets to the FBI (Federal Bureau of Investigations) wavelets when used for peak finding in noisy data. They will show that in this instance, their filters perform much better than the FBI wavelets.

  10. Spanish Peaks, Sangre de Cristo Range, Colorado

    NASA Technical Reports Server (NTRS)

    2002-01-01

    , 2002) Maher, Lewis J., Jr., 2001, Geology by Light Plane (accessed January 16, 2002) Penn, Brian, 1995-2001, Igneous Petrology of the Spanish Peaks (accessed January 16, 2002) Photograph STS-108-720-32 was taken in the December 2001 by the crew of Space Shuttle mission 108 using a Hasselblad camera with 250-mm lens, and is provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.

  11. A near infrared line list for NH3: Analysis of a Kitt Peak spectrum after 35 years

    NASA Astrophysics Data System (ADS)

    Barton, Emma J.; Yurchenko, Sergei N.; Tennyson, Jonathan; Béguier, Serge; Campargue, Alain

    2016-07-01

    A Fourier Transform (FT) absorption spectrum of room temperature NH3 in the region 7400-8640 cm-1 is analysed using a variational line list and ground state energies determined using the MARVEL procedure. The spectrum was measured by Dr. Catherine de Bergh in 1980 and is available from the Kitt Peak data center. The centers and intensities of 8468 ammonia lines were retrieved using a multiline fitting procedure. 2474 lines are assigned to 21 bands providing 1692 experimental energies in the range 7500-9200 cm-1. The spectrum was assigned by the joint use of the BYTe variational line list and combination differences. The assignments and experimental energies presented in this work are the first for ammonia in the region 7400-8640 cm-1, considerably extending the range of known vibrational-excited states.

  12. Measuring Your Peak Flow Rate

    MedlinePlus

    ... meter. Proper cleaning with mild detergent in hot water will keep your peak flow meter working accurately and may keep you healthier. Related Content News: American Lung Association Applauds EPA’s Update to Cross-State Air Pollution Rule News: American Lung Association Invests More Than $ ...

  13. Peak Stress Testing Protocol Framework

    EPA Science Inventory

    Treatment of peak flows during wet weather is a common challenge across the country for municipal wastewater utilities with separate and/or combined sewer systems. Increases in wastewater flow resulting from infiltration and inflow (I/I) during wet weather events can result in op...

  14. Hubbert's Peak -- A Physicist's View

    NASA Astrophysics Data System (ADS)

    McDonald, Richard

    2011-04-01

    Oil, as used in agriculture and transportation, is the lifeblood of modern society. It is finite in quantity and will someday be exhausted. In 1956, Hubbert proposed a theory of resource production and applied it successfully to predict peak U.S. oil production in 1970. Bartlett extended this work in publications and lectures on the finite nature of oil and its production peak and depletion. Both Hubbert and Bartlett place peak world oil production at a similar time, essentially now. Central to these analyses are estimates of total ``oil in place'' obtained from engineering studies of oil reservoirs as this quantity determines the area under the Hubbert's Peak. Knowing the production history and the total oil in place allows us to make estimates of reserves, and therefore future oil availability. We will then examine reserves data for various countries, in particular OPEC countries, and see if these data tell us anything about the future availability of oil. Finally, we will comment on synthetic oil and the possibility of carbon-neutral synthetic oil for a sustainable future.

  15. Potential of solar cooling systems for peak demand reduction

    SciTech Connect

    Pesaran, A A; Neymark, J

    1994-11-01

    We investigated the technical feasibility of solar cooling for peak demand reduction using a building energy simulation program (DOE2.1D). The system studied was an absorption cooling system with a thermal coefficient of performance of 0.8 driven by a solar collector system with an efficiency of 50% with no thermal storage. The analysis for three different climates showed that, on the day with peak cooling load, about 17% of the peak load could be met satisfactorily with the solar-assisted cooling system without any thermal storage. A performance availability analysis indicated that the solar cooling system should be designed for lower amounts of available solar resources that coincide with the hours during which peak demand reduction is required. The analysis indicated that in dry climates, direct-normal concentrating collectors work well for solar cooling; however, in humid climates, collectors that absorb diffuse radiation work better.

  16. Ultraviolet absorption cross sections of Cl sub 2 O sub 2 between 210 and 410 nm

    SciTech Connect

    Burkholder, J.B.; Orlando, J.J.; Howard, C.J. Univ. of Colorado, Boulder )

    1990-01-25

    The ultraviolet and infrared absorption cross sections of Cl{sub 2}O{sub 2} have been measured. The transient Cl{sub 2}O{sub 2} molecule was produced by using the gas-phase reaction ClO + ClO + M {yields} Cl{sub 2}O{sub 2} + M. Three independent ClO radical source reactions were used in this study: Cl + O{sub 3}, Cl + Cl{sub 2}O, and Cl + OClO. The Cl{sub 2}O{sub 2} UV absorption spectrum was recorded over the range 200-450 nm with a diode array spectrometer over the temperature range 205-250 K. The Cl{sub 2}O{sub 2} infrared absorption spectrum was recorded with a high-resolution Fourier transform spectrometer over the range 500-2,000 cm{sup {minus}1}. Both spectrometers were optically coupled to a fast flow multipass absorption cell. The UV absorption spectrum of Cl{sub 2}O{sub 2} is a structureless continuum with a peak at 245 nm. The measurable absorption extends out to 410 nm. The UV absorption cross section at the peak of the spectrum, 245 nm, was measured to be (6.5{sub {minus}0.5}{sup +0.8}) {times} 10{sup {minus}18} cm{sup 2}. Infrared absorption features centered at 560, 653, and 750 cm{sup {minus}1} have been assigned to the Cl{sub 2}O{sub 2} molecule. The present results are compared with other reported UV and IR measurements and the sources of discrepancies are discussed. The role of Cl{sub 2}O{sub 2} in atmospheric chemistry and in particular the Antarctic ozone hole are discussed.

  17. Gastrointestinal citrate absorption in nephrolithiasis

    NASA Technical Reports Server (NTRS)

    Fegan, J.; Khan, R.; Poindexter, J.; Pak, C. Y.

    1992-01-01

    Gastrointestinal absorption of citrate was measured in stone patients with idiopathic hypocitraturia to determine if citrate malabsorption could account for low urinary citrate. Citrate absorption was measured directly from recovery of orally administered potassium citrate (40 mEq.) in the intestinal lavage fluid, using an intestinal washout technique. In 7 stone patients citrate absorption, serum citrate levels, peak citrate concentration in serum and area under the curve were not significantly different from those of 7 normal subjects. Citrate absorption was rapid and efficient in both groups, with 96 to 98% absorbed within 3 hours. The absorption of citrate was less efficient from a tablet preparation of potassium citrate than from a liquid preparation, probably due to a delayed release of citrate from wax matrix. However, citrate absorption from solid potassium citrate was still high at 91%, compared to 98% for a liquid preparation. Thus, hypocitraturia is unlikely to be due to an impaired gastrointestinal absorption of citrate in stone patients without overt bowel disease.

  18. METHOD OF PEAK CURRENT MEASUREMENT

    DOEpatents

    Baker, G.E.

    1959-01-20

    The measurement and recording of peak electrical currents are described, and a method for utilizing the magnetic field of the current to erase a portion of an alternating constant frequency and amplitude signal from a magnetic mediums such as a magnetic tapes is presented. A portion of the flux from the current carrying conductor is concentrated into a magnetic path of defined area on the tape. After the current has been recorded, the tape is played back. The amplitude of the signal from the portion of the tape immediately adjacent the defined flux area and the amplitude of the signal from the portion of the tape within the area are compared with the amplitude of the signal from an unerased portion of the tape to determine the percentage of signal erasure, and thereby obtain the peak value of currents flowing in the conductor.

  19. SPANISH PEAKS PRIMITIVE AREA, MONTANA.

    USGS Publications Warehouse

    Calkins, James A.; Pattee, Eldon C.

    1984-01-01

    A mineral survey of the Spanish Peaks Primitive Area, Montana, disclosed a small low-grade deposit of demonstrated chromite and asbestos resources. The chances for discovery of additional chrome resources are uncertain and the area has little promise for the occurrence of other mineral or energy resources. A reevaluation, sampling at depth, and testing for possible extensions of the Table Mountain asbestos and chromium deposit should be undertaken in the light of recent interpretations regarding its geologic setting.

  20. A simple pharmacokinetics subroutine for modeling double peak phenomenon.

    PubMed

    Mirfazaelian, Ahmad; Mahmoudian, Massoud

    2006-04-01

    Double peak absorption has been described with several orally administered drugs. Numerous reasons have been implicated in causing the double peak. DRUG-KNT--a pharmacokinetic software developed previously for fitting one and two compartment kinetics using the iterative curve stripping method--was modified and a revised subroutine was incorporated to solve double-peak models. This subroutine considers the double peak as two hypothetical doses administered with a time gap. The fitting capability of the presented model was verified using four sets of data showing double peak profiles extracted from the literature (piroxicam, ranitidine, phenazopyridine and talinolol). Visual inspection and statistical diagnostics showed that the present algorithm provided adequate curve fit disregarding the mechanism involved in the emergence of the secondary peaks. Statistical diagnostic parameters (RSS, AIC and R2) generally showed good fitness in the plasma profile prediction by this model. It was concluded that the algorithm presented herein provides adequate predicted curves in cases of the double peak phenomenon. PMID:16400712

  1. Dual-peak dose measurement for radiochromic films by a newly developed spectral microdensitometer

    SciTech Connect

    Lee, K.Y.; Fung, K.K.L.; Kwok, C.S.

    2005-06-15

    Radiochromic film (RCF) dosimetry is usually based on densitometric methods which use an analyzing light source of a fixed or a broad spectrum of wavelengths. These methods have not exploited the sensitivity of the dose response of the RCF otherwise attainable by using a light source with wavelengths peaked at the two absorption peaks in the absorption spectrum of the RCF. A new algorithm of dual-peak dose measurement for the RCF has been proposed in this paper to make use of these dual absorption peaks to achieve the maximum attainable sensitivity. This technique relies on the measurement of the transmittance of the RCF at the wavelength of the major and minor absorption peaks, respectively. The dual-peak dose measurement is accomplished with the aid of a novel spectral microdensitometer developed in our Institute. The microdensitometer utilizes a monochromator to provide a light source of which the wavelength can be matched precisely to the wavelength of the absorption peaks of the RCF. The doses obtained at these wavelengths are fed into a weighted objective function and an optimum dose is searched by minimizing the objective function to give the best estimate of the dose deposited on the film. An initial test shows that there is a good agreement between the estimated and actual dose deposited; and the maximum discrepancy was found to be less than 1%.

  2. The Sacramento Peak fast microphotometer

    NASA Technical Reports Server (NTRS)

    Arrambide, M. R.; Dunn, R. B.; Healy, A. W.; Porter, R.; Widener, A. L.; November, L. J.; Spence, G. E.

    1984-01-01

    The Sacramento Peak Observatory Fast Microphotometer translates an optical system that includes a laser and photodiode detector across the film to scan the Y direction. A stepping motor moves the film gate in the X direction. This arrangement affords high positional accuracy, low noise (0.002 RMS density units), modest speed (5000 points/second), large dynamic range (4.5 density units), high stability (0.005 density units), and low scattered light. The Fast Microphotometer is interfaced to the host computer by a 6502 microprocessor.

  3. GRANITE PEAK ROADLESS AREA, CALIFORNIA.

    USGS Publications Warehouse

    Huber, Donald F.; Thurber, Horace K.

    1984-01-01

    The Granite Peak Roadless Area occupies an area of about 5 sq mi in the southern part of the Trinity Alps of the Klamath Mountains, about 12 mi north-northeast of Weaverville, California. Rock and stream-sediment samples were analyzed. All streams draining the roadless area were sampled and representative samples of the rock types in the area were collected. Background values were established for each element and anomalous values were examined within their geologic settings and evaluated for their significance. On the basis of mineral surveys there seems little likelihood for the occurrence of mineral or energy resources.

  4. Maxometers (peak wind speed anemometers)

    NASA Technical Reports Server (NTRS)

    Kaufman, J. W.; Camp, D. W.; Turner, R. E. (Inventor)

    1973-01-01

    An instrument for measuring peak wind speeds under severe environmental conditions is described, comprising an elongated cylinder housed in an outer casing. The cylinder contains a piston attached to a longitudinally movable guided rod having a pressure disk mounted on one projecting end. Wind pressure against the pressure disk depresses the movable rod. When the wind reaches its maximum speed, the rod is locked by a ball clutch mechanism in the position of maximum inward movement. Thereafter maximum wind speed or pressure readings may be taken from calibrated indexing means.

  5. North Twin Peak in super resolution

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This pair of images shows the result of taking a sequence of 25 identical exposures from the Imager for Mars Pathfinder (IMP) of the northern Twin Peak, with small camera motions, and processing them with the Super-Resolution algorithm developed at NASA's Ames Research Center.

    The upper image is a representative input image, scaled up by a factor of five, with the pixel edges smoothed out for a fair comparison. The lower image allows significantly finer detail to be resolved.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    The super-resolution research was conducted by Peter Cheeseman, Bob Kanefsky, Robin Hanson, and John Stutz of NASA's Ames Research Center, Mountain View, CA. More information on this technology is available on the Ames Super Resolution home page at

    http://ic-www.arc.nasa.gov/ic/projects/bayes-group/ group/super-res/

  6. Photoluminescence of a Te4+ center in zinc borate glass.

    PubMed

    Masai, Hirokazu; Yamada, Yasuhiro; Okumura, Shun; Kanemitsu, Yoshihiko; Yoko, Toshinobu

    2013-10-01

    Photoluminescent (PL) properties related to Te(4+) species in zinc borate glasses are examined. Broad emission was observed by the excitation of the PL excitation peak of Te(4+) present at the optical absorption edge. The emission intensity of Te(4+) in 5TeO(2)-50ZnO-45B(2)O(3) glass was thermally quenched in a temperature region over 100 K, suggesting that concentration quenching preferentially occurred. The lifetime of the emission was approximately 2.5 μs, which is characteristic of relaxation from the triplet excitation state of an ns(2)-type center. PMID:24081051

  7. Plasma dispersion effect assisted nanoscopy based on tuning of absorption and scattering resonances of nanoparticles

    NASA Astrophysics Data System (ADS)

    Danan, Yossef; Ilovitsh, Tali; Liu, Danping; Pinhas, Hadar; Sinvani, Moshe; Ramon, Yehonatan; Azougi, Jonathan; Douplik, Alexandre; Zalevsky, Zeev

    2016-03-01

    In this paper we present gold nanoparticles coated with silicon that switch the order between the scattering and the absorption magnitude at the resonance peak and tune the plasmon resonance over the spectrum. This is obtained by modifying the refractive index of the silicon coating of the nanoparticle by illuminating it with a pumping light due to the plasma dispersion effect in silicon. We also report how changing the diffraction limited point spread function through the utilization of plasma dispersion effect of the above mentioned silicon coated nanoparticles allows doing imaging with sub wavelength resolution. The plasma dispersion effect can increase the absorption coefficient of the silicon, when illuminated with a focused laser beam and as explained above it can also tune the absorption versus scattering properties of the nanoparticle. Due to the Gaussian nature of the laser illumination which has higher intensity at its peak, the plasma dispersion effect is more significant at the center of the illumination. As a consequence, the reflected light from probe beam at the near infra-red region has a sub wavelength dip that overlaps with the location of the pump illumination peak. This dip has a higher spatial frequency than an ordinary Gaussian, which enables to achieve super resolution.

  8. Analysis of frequency dependent pump light absorption

    NASA Astrophysics Data System (ADS)

    Wohlmuth, Matthias; Pflaum, Christoph

    2011-03-01

    Simulations have to accurately model thermal lensing in order to help improving resonator design of diode pumped solid state lasers. To this end, a precise description of the pump light absorption is an important prerequisite. In this paper, we discuss the frequency dependency of the pump light absorption in the laser crystal and its influence on the simulated laser performance. The results show that the pump light absorption has to include the spectral overlap of the emitting pump source and the absorbing laser material. This information can either be used for a fully frequency dependent absorption model or, at least in the shown examples, to compute an effective value for an exponential Beer-Lambert law of absorption. This is particularly significant at pump wavelengths coinciding with a peak of absorption. Consequences for laser stability and performance are analyzed for different pump wavelengths in a Nd:YAG laser.

  9. The use of the Kitt Peak IDS in determining galaxy redshifts - Results for five clusters

    NASA Astrophysics Data System (ADS)

    Hintzen, P.

    1980-06-01

    The redshifts of 71 galaxies in five clusters determined using the Kitt Peak Image Dissector Scanner (IDS) are presented and the accuracy of velocities determined with the IDS system is discussed. Data were obtained from observations of absorption or emission lines in the range 3600-5400 A using the IDS on a 2.1-m telescope and effective apertures of 3.8 x 10.3 arcsec from galaxies belonging to the AWM 7 = NGC 1129, A 1213, A 1795, A 2589 and A 2666 clusters. Wavelength errors due to mechanical flexure, off-center guiding and spectrum noise are estimated to provide an uncertainty of + or - 1.21 A or 92 km/sec in measurements of a given spectrum, and comparison of the velocities determined by the Kitt Peak IDS with those determined by the Lick IDS supports the error value. Implications of the mean heliocentric redshifts and relativistically correct velocity dispersions obtained for the structure and membership of the AWM 7 cluster are discussed.

  10. Infrared absorption of hydrogen-related defects in ammonothermal GaN

    NASA Astrophysics Data System (ADS)

    Suihkonen, Sami; Pimputkar, Siddha; Speck, James S.; Nakamura, Shuji

    2016-05-01

    Polarization controlled Fourier transform infrared (FTIR) absorption measurements were performed on a high quality m-plane ammonothermal GaN crystal grown using basic chemistry. The polarization dependence of characteristic absorption peaks of hydrogen-related defects at 3000-3500 cm-1 was used to identify and determine the bond orientation of hydrogenated defect complexes in the GaN lattice. Majority of hydrogen was found to be bonded in gallium vacancy complexes decorated with one to three hydrogen atoms (VGa-H1,2,3) but also hydrogenated oxygen defect complexes, hydrogen in bond-center sites, and lattice direction independent absorption were observed. Absorption peak intensity was used to determine a total hydrogenated VGa density of approximately 4 × 1018 cm-3, with main contribution from VGa-H1,2. Also, a significant concentration of electrically passive VGa-H3 was detected. The high density of hydrogenated defects is expected to have a strong effect on the structural, optical, and electrical properties of ammonothermal GaN crystals.

  11. The electronic absorption edge of petroleum

    SciTech Connect

    Mullins, O.C.; Mitra-Kirtley, S.; Zhu, Yifu

    1992-09-01

    The electronic absorption spectra of more than 20 crude oils and asphaltenes are examined. The spectral location of the electronic absorption edge varies over a wide range, from the near-infrared for heavy oils and asphaltenes to the near-UV for gas condensates. The functional form of the electronic absorption edge for all crude oils (measured) is characteristic of the {open_quotes}Urbach tail,{close_quotes} a phenomenology which describes electronic absorption edges in wide-ranging materials. The crude oils all show similar Urbach widths, which are significantly larger than those generally found for various materials but are similar to those previously reported for asphaltenes. Monotonically increasing absorption at higher photon energy continues for all crude oils until the spectral region is reached where single-ring aromatics dominate absorption. However, the rate of increasing absorption at higher energies moderates, thereby deviating from the Urbach behavior. Fluorescence emission spectra exhibit small red shifts from the excitation wavelength and small fluorescence peak widths in the Urbach regions of different crude oils, but show large red shifts and large peak widths in spectral regions which deviate from the Urbach behavior. This observation implies that the Urbach spectral region is dominated by lowest-energy electronic absorption of corresponding chromophores. Thus, the Urbach tail gives a direct measure of the population distribution of chromophores in crude oils. Implied population distributions are consistent with thermally activated growth of large chromophores from small ones. 12 refs., 8 figs.

  12. Peak load management: Potential options

    SciTech Connect

    Englin, J.E.; De Steese, J.G.; Schultz, R.W.; Kellogg, M.A.

    1989-10-01

    This report reviews options that may be alternatives to transmission construction (ATT) applicable both generally and at specific locations in the service area of the Bonneville Power Administration (BPA). Some of these options have potential as specific alternatives to the Shelton-Fairmount 230-kV Reinforcement Project, which is the focus of this study. A listing of 31 peak load management (PLM) options is included. Estimated costs and normalized hourly load shapes, corresponding to the respective base load and controlled load cases, are considered for 15 of the above options. A summary page is presented for each of these options, grouped with respect to its applicability in the residential, commercial, industrial, and agricultural sectors. The report contains comments on PLM measures for which load shape management characteristics are not yet available. These comments address the potential relevance of the options and the possible difficulty that may be encountered in characterizing their value should be of interest in this investigation. The report also identifies options that could improve the efficiency of the three customer utility distribution systems supplied by the Shelton-Fairmount Reinforcement Project. Potential cogeneration options in the Olympic Peninsula are also discussed. These discussions focus on the options that appear to be most promising on the Olympic Peninsula. Finally, a short list of options is recommended for investigation in the next phase of this study. 9 refs., 24 tabs.

  13. Analyzing Water's Optical Absorption

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A cooperative agreement between World Precision Instruments (WPI), Inc., and Stennis Space Center has led the UltraPath(TM) device, which provides a more efficient method for analyzing the optical absorption of water samples at sea. UltraPath is a unique, high-performance absorbance spectrophotometer with user-selectable light path lengths. It is an ideal tool for any study requiring precise and highly sensitive spectroscopic determination of analytes, either in the laboratory or the field. As a low-cost, rugged, and portable system capable of high- sensitivity measurements in widely divergent waters, UltraPath will help scientists examine the role that coastal ocean environments play in the global carbon cycle. UltraPath(TM) is a trademark of World Precision Instruments, Inc. LWCC(TM) is a trademark of World Precision Instruments, Inc.

  14. Resonant Orbits and the High Velocity Peaks toward the Bulge

    NASA Astrophysics Data System (ADS)

    Molloy, Matthew; Smith, Martin C.; Evans, N. Wyn; Shen, Juntai

    2015-10-01

    We extract the resonant orbits from an N-body bar that is a good representation of the Milky Way, using the method recently introduced by Molloy et al. By decomposing the bar into its constituent orbit families, we show that they are intimately connected to the boxy-peanut shape of the density. We highlight the imprint due solely to resonant orbits on the kinematic landscape toward the Galactic center. The resonant orbits are shown to have distinct kinematic features and may be used to explain the cold velocity peak seen in the Apache Point Observatory Galactic Evolution Experiment commissioning data. We show that high velocity peaks are a natural consequence of the motions of stars in the 2:1 orbit family and that stars on other higher order resonances can contribute to the peaks. The locations of the peaks vary with bar angle and, with the tacit assumption that the observed peaks are due to the 2:1 family, we find that the locations of the high velocity peaks correspond to bar angles in the range {10}\\circ ≲ {θ }{bar}≲ 25^\\circ . However, some important questions about the nature of the peaks remain, such as their apparent absence in other surveys of the Bulge and the deviations from symmetry between equivalent fields in the north and south. We show that the absence of a peak in surveys at higher latitudes is likely due to the combination of a less prominent peak and a lower number density of bar supporting orbits at these latitudes.

  15. Determination of peak expiratory flow.

    PubMed

    Kano, S; Burton, D L; Lanteri, C J; Sly, P D

    1993-10-01

    It is still unknown whether peak expiratory flow (PEF) is determined by "wave speed" flow limitation in the airways. To investigate the influences of airway mechanical properties on PEF, five healthy adults performed maximal forced expiratory effort (MFEE) manoeuvres, in the standard manner and following breathholds at total lung capacity (TLC) of 2 s and 10 s. Oesophageal pressure (Poes) was measured as an index of respiratory effort. Subjects also performed a MFEE following a 10 s breathhold during which intrathoracic pressure was voluntarily raised by a Valsalva manoeuvre, which would increase transmural pressure and cross-sectional area of the extrathoracic airway. Additional MFEEs were performed with the neck fully flexed and extended, to change longitudinal tracheal tension. In separate studies, PEF was measured with a spirometer and with a pneumotachograph. Breathholds at TLC (2 s and 10 s), and neck flexion reduced PEF by a mean of 9.8% (SD 2.9%), 9.6% (SD 1.6%), and 8.7% (SD 2.8%), respectively, when measured with the spirometer. The same pattern of results was seen when measured with the pneumotachograph. These reductions occurred despite similar respiratory effort. Voluntarily raising intrathoracic pressure during a 10 s breathhold did not reverse a fall in PEF. MFEE manoeuvre with neck extension did not result in an increase in PEF, the group mean % changes being -3.0% (SD 5.0%). We conclude that these results do not allow the hypothesis that "wave-speed" (Vws) is reached at PEF to be rejected. A breathhold at TLC could increase airway wall compliance by allowing stress-relaxation of the airway, thus reducing the "Vws" achievable. PMID:8287953

  16. Synthetic Antenna Functioning As Light Harvester in the Whole Visible Region for Enhanced Hybrid Photosynthetic Reaction Centers.

    PubMed

    Hassan Omar, Omar; la Gatta, Simona; Tangorra, Rocco Roberto; Milano, Francesco; Ragni, Roberta; Operamolla, Alessandra; Argazzi, Roberto; Chiorboli, Claudio; Agostiano, Angela; Trotta, Massimo; Farinola, Gianluca M

    2016-07-20

    The photosynthetic reaction center (RC) from the Rhodobacter sphaeroides bacterium has been covalently bioconjugated with a NIR-emitting fluorophore (AE800) whose synthesis was specifically tailored to act as artificial antenna harvesting light in the entire visible region. AE800 has a broad absorption spectrum with peaks centered in the absorption gaps of the RC and its emission overlaps the most intense RC absorption bands, ensuring a consistent increase of the protein optical cross section. The covalent hybrid AE800-RC is stable and fully functional. The energy collected by the artificial antenna is transferred to the protein via FRET mechanism, and the hybrid system outperforms by a noteworthy 30% the overall photochemical activity of the native protein under the entire range of visible light. This improvement in the optical characteristic of the photoenzyme demonstrates the effectiveness of the bioconjugation approach as a suitable route to new biohybrid materials for energy conversion, photocatalysis, and biosensing. PMID:27245093

  17. Peak Ring Craters and Multiring Basins

    NASA Astrophysics Data System (ADS)

    Melosh, H. J.

    2015-09-01

    Understanding of the mechanics of peak-ring crater and basin formation has expanded greatly due to the high precision data on lunar gravity from GRAIL. Peak rings coincide with the edges of underlying mantle uplifts on the Moon.

  18. Peak-flow characteristics of Virginia streams

    USGS Publications Warehouse

    Austin, Samuel H.; Krstolic, Jennifer L.; Wiegand, Ute

    2011-01-01

    Peak-flow annual exceedance probabilities, also called probability-percent chance flow estimates, and regional regression equations are provided describing the peak-flow characteristics of Virginia streams. Statistical methods are used to evaluate peak-flow data. Analysis of Virginia peak-flow data collected from 1895 through 2007 is summarized. Methods are provided for estimating unregulated peak flow of gaged and ungaged streams. Station peak-flow characteristics identified by fitting the logarithms of annual peak flows to a Log Pearson Type III frequency distribution yield annual exceedance probabilities of 0.5, 0.4292, 0.2, 0.1, 0.04, 0.02, 0.01, 0.005, and 0.002 for 476 streamgaging stations. Stream basin characteristics computed using spatial data and a geographic information system are used as explanatory variables in regional regression model equations for six physiographic regions to estimate regional annual exceedance probabilities at gaged and ungaged sites. Weighted peak-flow values that combine annual exceedance probabilities computed from gaging station data and from regional regression equations provide improved peak-flow estimates. Text, figures, and lists are provided summarizing selected peak-flow sites, delineated physiographic regions, peak-flow estimates, basin characteristics, regional regression model equations, error estimates, definitions, data sources, and candidate regression model equations. This study supersedes previous studies of peak flows in Virginia.

  19. Discourse Peak as Zone of Turbulence.

    ERIC Educational Resources Information Center

    Longacre, Robert E.

    Defining peak as the climax of discourse, this paper argues that it is important to identify peak in order to get at the overall grammar of a given discourse. The paper presents case studies in which four instances of peak in narrative discourses occur in languages from four different parts of the world. It also illustrates the occurrence of a…

  20. The peak electromagnetic power radiated by lightning return strokes

    NASA Technical Reports Server (NTRS)

    Krider, E. P.; Guo, C.

    1983-01-01

    Estimates of the peak electromagnetic (EM) power radiated by return strokes have been made by integrating the Poynting vector of measured fields over an imaginary hemispherical surface that is centered on the lightning source, assuming that ground losses are negligible. Values of the peak EM power from first and subsequent strokes have means and standard deviations of 2 + or - 2 x 10 to the 10th and 3 + or - 4 x 10 to the 9th W, respectively. The average EM power that is radiated by subsequent strokes, at the time of the field peak, is about 2 orders of magnitude larger than the optical power that is radiated by these strokes in the wavelength interval from 0.4 to 1.1 micron; hence an upper limit to the radiative efficiency of a subsequent stroke is of the order of 1 percent or less at this time.

  1. Peak Wind Tool for General Forecasting

    NASA Technical Reports Server (NTRS)

    Barrett, Joe H., III

    2010-01-01

    The expected peak wind speed of the day is an important forecast element in the 45th Weather Squadron's (45 WS) daily 24-Hour and Weekly Planning Forecasts. The forecasts are used for ground and space launch operations at the Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS). The 45 WS also issues wind advisories for KSC/CCAFS when they expect wind gusts to meet or exceed 25 kt, 35 kt and 50 kt thresholds at any level from the surface to 300 ft. The 45 WS forecasters have indicated peak wind speeds are challenging to forecast, particularly in the cool season months of October - April. In Phase I of this task, the Applied Meteorology Unit (AMU) developed a tool to help the 45 WS forecast non-convective winds at KSC/CCAFS for the 24-hour period of 0800 to 0800 local time. The tool was delivered as a Microsoft Excel graphical user interface (GUI). The GUI displayed the forecast of peak wind speed, 5-minute average wind speed at the time of the peak wind, timing of the peak wind and probability the peak speed would meet or exceed 25 kt, 35 kt and 50 kt. For the current task (Phase II ), the 45 WS requested additional observations be used for the creation of the forecast equations by expanding the period of record (POR). Additional parameters were evaluated as predictors, including wind speeds between 500 ft and 3000 ft, static stability classification, Bulk Richardson Number, mixing depth, vertical wind shear, temperature inversion strength and depth and wind direction. Using a verification data set, the AMU compared the performance of the Phase I and II prediction methods. Just as in Phase I, the tool was delivered as a Microsoft Excel GUI. The 45 WS requested the tool also be available in the Meteorological Interactive Data Display System (MIDDS). The AMU first expanded the POR by two years by adding tower observations, surface observations and CCAFS (XMR) soundings for the cool season months of March 2007 to April 2009. The POR was expanded

  2. The HI absorption "Zoo"

    NASA Astrophysics Data System (ADS)

    Geréb, K.; Maccagni, F. M.; Morganti, R.; Oosterloo, T. A.

    2015-03-01

    We present an analysis of the H I 21 cm absorption in a sample of 101 flux-selected radio AGN (S1.4 GHz> 50 mJy) observed with the Westerbork Synthesis Radio Telescope (WSRT). We detect H I absorption in 32 objects (30% of the sample). In a previous paper, we performed a spectral stacking analysis on the radio sources, while here we characterize the absorption spectra of the individual detections using the recently presented busy function. The H I absorption spectra show a broad variety of widths, shapes, and kinematical properties. The full width half maximum (FWHM) of the busy function fits of the detected H I lines lies in the range 32 km s-1peak absorption (FW20) lies in the range 63 km s-1 200 km s-1). We study the kinematical and radio source properties of each group, with the goal of identifying different morphological structures of H I. Narrow lines mostly lie at the systemic velocity and are likely produced by regularly rotating H I disks or gas clouds. More H I disks can be present among galaxies with lines of intermediate widths; however, the H I in these sources is more unsettled. We study the asymmetry parameter and blueshift/redshift distribution of the lines as a function of their width. We find a trend for which narrow profiles are also symmetric, while broad lines are the most asymmetric. Among the broadest lines, more lines appear blueshifted than redshifted, similarly to what was found by previous studies. Interestingly, symmetric broad lines are absent from the sample. We argue that if a profile is broad, it is also asymmetric and shifted relative to the systemic velocity because it is tracing unsettled H I gas. In particular, besides three of the broadest (up to FW20 = 825 km s-1

  3. Inhibition of norfloxacin absorption by dairy products.

    PubMed Central

    Kivistö, K T; Ojala-Karlsson, P; Neuvonen, P J

    1992-01-01

    Seven healthy subjects received, after an overnight fast, a single 200-mg oral dose of norfloxacin with water, whole milk, and unflavored yoghurt. Coadministration of milk or yoghurt reduced the extent of norfloxacin absorption and the mean peak concentration in plasma by approximately 50%. Taking of norfloxacin with these liquid dairy products should be avoided. PMID:1605619

  4. Large persistent photochromic effect due to DX centers in AlSb doped with selenium

    SciTech Connect

    Becla, P.; Witt, A.G.; Lagowski, J.; Walukiewicz, W.

    1995-04-01

    A large photochromic effect has been observed in bulk AlSb crystals doped with Se. Illumination with light of energy higher than 1 eV leads to an increase of the absorption coefficient in the spectral range 0.1 to 1.6 eV. The enhanced absorption is persistent at temperatures below about K. The effect is a manifestation of a DX-like bistability of Se donors. The illumination transfers the from the DX center to a metastable hydrogenic level. The increased absorption with peaks around 0.2 eV and 0.5 is due to photoionization from the donor level to X{sub l} and X{sub 3} minima of the conduction band.

  5. Luminescence properties and optical absorption of X ray-irradiated KBr: Ce3(+), Tb(3+) crystals.

    PubMed

    Bangaru, S; Saradha, K; Muralidharan, G

    2015-03-01

    This paper reports that KBr doubly doped with Tb(3+) and Ce(3+) were prepared by Bridgman-Stockbarger method and characterized by Optical absorption, Photoluminescence (PL), Thermoluminescence (TL), Photo stimulated emission (PSL) and TL emission, after X-ray irradiation have been observed. The optical absorption measurement indicates that F and Z3 centers are formed in the crystal during X-ray irradiation process. It was attempted to incorporate a broad band of Ce(3+) sensitizer into the narrow band emission of Tb(3+) in the KBr host without reduction of emission intensity. Co-doping of Ce(3+) ions in KBr:Tb(3+) crystal showed a broad band emission due to the d-f transition of Ce(3+) and a reduction in the intensity of emission peaks due to (5)days → (7)F6 transition of Tb(3+) when they were excited at 250 nm. These results supported that an effective energy transfer occurs from Ce(3+) to Tb(3+) in the KBr host. Co-doping Ce(3+) ions greatly intensified the excitation peak at 260 nm for the emission at 390 nm of Tb(3+) which means that more lattice defects, involved in the energy absorption and transfer to Tb(3+), are formed by the Ce(3+) co-doping. The integrated light intensity is two orders of magnitude higher as compared to the undoped samples for similar doses of irradiation and heating rate. Thermoluminescence process has been identified due to thermal mobilization of F-electrons and this causes peaks at 371 K and at 427 K, 457 K in KBr: Ce(3+), Tb(3+) crystals. The defects generated by irradiation were monitored by optical absorption and trap parameters for the TL process were calculated and presented. PMID:25585645

  6. First attempt to monitor atmospheric glyoxal using differential absorption lidar

    NASA Astrophysics Data System (ADS)

    Mei, Liang; Lundin, Patrik; Somesfalean, Gabriel; Hu, Jiandong; Zhao, Guangyu; Svanberg, Sune; Bood, Joakim; Vrekoussis, Mihalis; Papayannis, Alexandros

    2012-11-01

    Glyoxal (CHOCHO), as an indicator of photochemical "hot spots", was for the first time the subject of a differential absorption lidar (DIAL) campaign. The strongest absorption line of glyoxal in the blue wavelength region - 455.1 nm - was chosen as the experimental absorption wavelength. In order to handle the effects of absorption cross-section variation of the interfering gas - nitrogen dioxide (NO2) - three-wavelength DIAL measurements simultaneously detecting glyoxal and NO2, were performed. The differential absorption curves, recorded in July 2012, indicate an extremely low glyoxal concentration in Lund, Sweden, although it is expected to be peaking at this time of the year.

  7. Super-Resonant Intracavity Coherent Absorption

    NASA Astrophysics Data System (ADS)

    Malara, P.; Campanella, C. E.; Giorgini, A.; Avino, S.; de Natale, P.; Gagliardi, G.

    2016-07-01

    The capability of optical resonators to extend the effective radiation-matter interaction length originates from a multipass effect, hence is intrinsically limited by the resonator’s quality factor. Here, we show that this constraint can be overcome by combining the concepts of resonant interaction and coherent perfect absorption (CPA). We demonstrate and investigate super-resonant coherent absorption in a coupled Fabry-Perot (FP)/ring cavity structure. At the FP resonant wavelengths, the described phenomenon gives rise to split modes with a nearly-transparent peak and a peak whose transmission is exceptionally sensitive to the intracavity loss. For small losses, the effective interaction pathlength of these modes is proportional respectively to the ratio and the product of the individual finesse coefficients of the two resonators. The results presented extend the conventional definition of resonant absorption and point to a way of circumventing the technological limitations of ultrahigh-quality resonators in spectroscopy and optical sensing schemes.

  8. Super-Resonant Intracavity Coherent Absorption

    PubMed Central

    Malara, P.; Campanella, C. E.; Giorgini, A.; Avino, S.; De Natale, P.; Gagliardi, G.

    2016-01-01

    The capability of optical resonators to extend the effective radiation-matter interaction length originates from a multipass effect, hence is intrinsically limited by the resonator’s quality factor. Here, we show that this constraint can be overcome by combining the concepts of resonant interaction and coherent perfect absorption (CPA). We demonstrate and investigate super-resonant coherent absorption in a coupled Fabry-Perot (FP)/ring cavity structure. At the FP resonant wavelengths, the described phenomenon gives rise to split modes with a nearly-transparent peak and a peak whose transmission is exceptionally sensitive to the intracavity loss. For small losses, the effective interaction pathlength of these modes is proportional respectively to the ratio and the product of the individual finesse coefficients of the two resonators. The results presented extend the conventional definition of resonant absorption and point to a way of circumventing the technological limitations of ultrahigh-quality resonators in spectroscopy and optical sensing schemes. PMID:27364475

  9. On the trail of double peak hydrographs

    NASA Astrophysics Data System (ADS)

    Martínez-Carreras, Núria; Hissler, Christophe; Gourdol, Laurent; Klaus, Julian; Juilleret, Jérôme; François Iffly, Jean; McDonnell, Jeffrey J.; Pfister, Laurent

    2016-04-01

    A double peak hydrograph features two peaks as a response to a unique rainfall pulse. The first peak occurs at the same time or shortly after the precipitation has started and it corresponds to a fast catchment response to precipitation. The delayed peak normally starts during the recession of the first peak, when the precipitation has already ceased. Double peak hydrographs may occur for various reasons. They can occur (i) in large catchments when lag times in tributary responses are large, (ii) in urban catchments where the first peak is often caused by direct surface runoff on impervious land cover, and the delayed peak to slower subsurface flow, and (iii) in non-urban catchments, where the first and the delayed discharge peaks are explained by different runoff mechanisms (e.g. overland flow, subsurface flow and/or deep groundwater flow) that have different response times. Here we focus on the third case, as a formal description of the different hydrological mechanisms explaining these complex hydrological dynamics across catchments with diverse physiographic characteristics is still needed. Based on a review of studies documenting double peak events we have established a formal classification of catchments presenting double peak events based on their regolith structure (geological substratum and/or its weathered products). We describe the different hydrological mechanisms that trigger these complex hydrological dynamics across each catchment type. We then use hydrometric time series of precipitation, runoff, soil moisture and groundwater levels collected in the Weierbach (0.46 km2) headwater catchment (Luxembourg) to better understand double peak hydrograph generation. Specifically, we aim to find out (1) if the generation of a double peak hydrograph is a threshold process, (2) if the hysteretic relationships between storage and discharge are consistent during single and double peak hydrographs, and (3) if different functional landscape units (the hillslopes

  10. Cause of absorption band shift of disperse red-13 attached on silica spheres

    NASA Astrophysics Data System (ADS)

    Kim, Byoung-Ju; Kim, Hyung-Deok; Kim, Na-Rae; Bang, Byeong-Gyu; Park, Eun-Hye; Kang, Kwang-Sun

    2015-08-01

    A reversible color change and large absorption band shift have been observed for the disperse red-13 (DR-13) attached on the surface of the monodisperse silica spheres. Two step synthetic processes including urethane bond formation and hydrolysis-condensation reactions were used to attach the DR-13 on the surface of the silica spheres. After the reaction, the characteristic absorption peak at 2270 cm-1 representing the -N=C=O asymmetric stretching vibration disappeared, and the a new absorption peak at 1700 cm-1 corresponding the C=O stretching vibration appeared. A visual and reversible color change was observed before and after wetting in alcohol. Although the absorption peak of DR-13 in alcohol is at 510 nm, the absorption peak shifts to 788 nm when it is dried. The absorption peak shifts to 718 nm when it is wetted in alcohol. This result can be explained by the formation of intramolecular charge transfer band.

  11. Clustering properties of high matter density peaks from UVES observations of QSO pairs

    NASA Astrophysics Data System (ADS)

    D'Odorico, V.

    2003-06-01

    The association of high H 0 column density absorption systems in QSO spectra with galactic objects has been widely verified at redshifts up to z ~ 1, by direct imaging of QSO fields and follow-up spectroscopy (Guillemin & Bergeron 1997; Le Brun et al. 1997). We study the transverse clustering properties of these tracers of high matter density peaks, by looking for coincident absorption systems in adjacent lines of sight toward QSO pairs and groups (D'Odorico et al. 2002).

  12. X-Ray Absorption Spectra of Uranium by Synchrotron Radiation

    NASA Astrophysics Data System (ADS)

    Adachi, Hirohiko; Fujima, Kazumi; Taniguchi, Kazuo; Miyake, Chie; Imoto, Shosuke

    1981-08-01

    The X-ray absorption spectra of U, UO2 and UCl4 near the U OIV and OV thresholds have been measured by use of synchrotron radiation. The absorption peaks at about 100 eV and 110 eV are observed for all of these materials. However, the detailed structure of the spectra depend on the chemical state.

  13. Infra-red absorption lines by molecules in grain mantles

    NASA Astrophysics Data System (ADS)

    Hagen, W.; Allamandola, L. J.; Greenberg, J. M.

    1980-06-01

    The laboratory spectrum of a solid mixture of H2O, CO, CH3OH, and NH3 at a temperature of 10 K reproduces the shape and peak positions of interstellar features. It is shown that the broad absorption features evident in the MIR spectra of some astronomical objects associated with interstellar dust can be explained by absorptions of molecules in grain mantles.

  14. Enhanced squeezing by absorption

    NASA Astrophysics Data System (ADS)

    Grünwald, P.; Vogel, W.

    2016-04-01

    Absorption is usually expected to be detrimental to quantum coherence effects. However, there have been few studies into the situation for complex absorption spectra. We consider the resonance fluorescence of excitons in a semiconductor quantum well. The creation of excitons requires absorption of the incoming pump-laser light. Thus, the absorption spectrum of the medium acts as a spectral filter for the emitted light. Surprisingly, absorption can even improve quantum effects, as is demonstrated for the squeezing of the resonance fluorescence of the quantum-well system. This effect can be explained by an improved phase matching due to absorption.

  15. Acetaminophen overdose associated with double serum concentration peaks

    PubMed Central

    Papazoglu, Cristian; Ang, Jonathan R.; Mandel, Michael; Basak, Prasanta; Jesmajian, Stephen

    2015-01-01

    Acetaminophen is the most commonly used analgesic–antipyretic medication in the United States. Acetaminophen overdose, a frequent cause of drug toxicity, has been recognized as the leading cause of fatal and non-fatal hepatic necrosis. N-Acetylcysteine is the recommended antidote for acetaminophen poisoning. Despite evidence on the efficacy of N-acetylcysteine for prevention of hepatic injury, controversy persists about the optimal duration of the therapy. Here, we describe the case of a 65-year-old male with acetaminophen overdose and opioid co-ingestion who developed a second peak in acetaminophen serum levels after completing the recommended 21-hour intravenous N-acetylcysteine protocol and when the standard criteria for monitoring drug levels was achieved. Prolongation of N-acetylcysteine infusion beyond the standard protocol, despite a significant gap in treatment, was critical for successful avoidance of hepatotoxicity. Delay in acetaminophen absorption may be associated with a second peak in serum concentration following an initial declining trend, especially in cases of concomitant ingestion of opioids. In patients with acetaminophen toxicity who co-ingest other medications that may potentially delay gastric emptying or in those with risk factors for delayed absorption of acetaminophen, we recommend close monitoring of aminotransferase enzyme levels, as well as trending acetaminophen concentrations until undetectable before discontinuing the antidote therapy. PMID:26653695

  16. Passive radio frequency peak power multiplier

    DOEpatents

    Farkas, Zoltan D.; Wilson, Perry B.

    1977-01-01

    Peak power multiplication of a radio frequency source by simultaneous charging of two high-Q resonant microwave cavities by applying the source output through a directional coupler to the cavities and then reversing the phase of the source power to the coupler, thereby permitting the power in the cavities to simultaneously discharge through the coupler to the load in combination with power from the source to apply a peak power to the load that is a multiplication of the source peak power.

  17. On the Evolution of and High-Energy Emission from GHz-Peaked-Spectrum Sources

    SciTech Connect

    Stawarz, L.; Ostorero, L.; Begelman, M.C.; Moderski, R.; Kataoka, J.; Wagner, S.

    2007-12-18

    Here we discuss evolution and broad-band emission of compact (< kpc) lobes in young radio sources. We propose a simple dynamical description for these objects, consisting of a relativistic jet propagating into a uniform gaseous medium in the central parts of an elliptical host. In the framework of the proposed model, we follow the evolution of ultrarelativistic electrons injected from a terminal hotspot of a jet to expanding lobes, taking into account their adiabatic energy losses as well as radiative cooling. This allows us to discuss the broad-band lobe emission of young radio sources. In particular, we argue that the observed spectral turnover in the radio synchrotron spectra of these objects cannot originate from the synchrotron self-absorption process but is most likely due to free-free absorption effects connected with neutral clouds of interstellar medium engulfed by the expanding lobes and photoionized by active centers. We also find a relatively strong and complex high-energy emission component produced by inverse-Compton up-scattering of various surrounding photon fields by the lobes electrons. We argue that such high energy radiation is strong enough to account for several observed properties of GHz-peaked-spectrum (GPS) radio galaxies at UV and X-ray frequencies. In addition, this emission is expected to extend up to GeV (or possibly even TeV) photon energies and can thus be probed by several modern {gamma}-ray instruments. In particular, we suggest that GPS radio galaxies should constitute a relatively numerous class of extragalactic sources detected by GLAST.

  18. Electromagnetically induced absorption via incoherent collisions

    SciTech Connect

    Yang Xihua; Sheng Jiteng; Xiao Min

    2011-10-15

    We conduct theoretical studies on electromagnetically induced absorption via incoherent collisions in an inhomogeneously broadened ladder-type three-level system with the density-matrix approach. The effects of the collision-induced coherence decay rates as well as the probe laser field intensity on the probe field absorption are examined. It is shown that with the increase of the collisional decay rates in a moderate range, a narrow dip due to electromagnetically induced transparency superimposed on the Doppler-broadened absorption background can be turned into a narrow peak under the conditions that the probe field intensity is not very weak as compared to the pump field, which results from the enhancement of constructive interference and suppression of destructive interference between one-photon and multiphoton transition pathways. The physical origin of the collision-assisted electromagnetically induced absorption is analyzed with a power-series solution of the density-matrix equations.

  19. Impedance Characteristics of the Plasma Absorption Probe

    NASA Astrophysics Data System (ADS)

    Yamazawa, Yohei

    2009-10-01

    The plasma absorption probe (PAP) is a diagnostics for determination of spatially resolved electron density.footnotetextH. Kokura, et al., Jpn. J. Appl. Phys. 38 5262 (1999). PAP has attracted considerable interest because of its applicability in a reactive plasma. The simple structure of the probe allows us a robust measurement while the mechanism of the absorption is complicated and there are still some uncertainty.footnotetextM. Lapke, et al., Appl. Phys. Lett. 90, 121502 (2007) In this study, we focus on the frequency characteristics of the impedance instead of the absorption spectrum. An electromagnetic field simulation reveals that there is only one parallel resonance in the impedance characteristics even in a case there are many peaks in absorption spectrum. Thus, the impedance characteristics provide a clue to understanding the mechanism.

  20. D-xylose absorption

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003606.htm D-xylose absorption To use the sharing features on this page, please enable JavaScript. D-xylose absorption is a laboratory test to determine ...

  1. Dust-on-snow and the Timing of Peak Streamflow in the Upper Rio Grande

    NASA Astrophysics Data System (ADS)

    Steele, C. M.; Elias, E.; Moffitt, A.; Beltran, I.; Rango, A.

    2015-12-01

    Dust radiative forcing on high elevation snowpack is well-documented in the southern Rockies. Various field studies show that dust deposits decrease snow albedo and increase absorption of solar radiation, leading to earlier snowmelt and peak stream flows. These findings have implications for the use of temperature-index snow runoff models (such as the Snowmelt Runoff Model [SRM]) for predicting streamflow. In previous work, we have used SRM to simulate historical streamflow from 26 Upper Rio Grande sub-basins. Because dust radiative forcing can alter the relation between temperature and snowmelt, we wanted to find out if there is evidence of dust radiative forcing and earlier snowmelt in our study basins, particularly for those years where SRM was less successful in simulating streamflow. To accomplish this we have used openly-available data such as EPA air quality station measurements of particulate matter up to 10 micrometers (PM10); streamflow data from the USGS National Water Information System and Colorado Division of Water Resources; temperature, precipitation and snow water equivalent (SWE) from NRCS SNOTEL stations and remotely sensed data products from the MODIS sensor. Initial analyses indicate that a connection between seasonal dust concentration and streamflow timing (date of onset of warm-season snowmelt, date of streamflow center-of-volume) can be detected. This is further supported by time series analysis of MODIS-derived estimates of snow albedo and dust radiative-forcing in alpine and open subalpine snow fields.

  2. The Boson peak in supercooled water.

    PubMed

    Kumar, Pradeep; Wikfeldt, K Thor; Schlesinger, Daniel; Pettersson, Lars G M; Stanley, H Eugene

    2013-01-01

    We perform extensive molecular dynamics simulations of the TIP4P/2005 model of water to investigate the origin of the Boson peak reported in experiments on supercooled water in nanoconfined pores, and in hydration water around proteins. We find that the onset of the Boson peak in supercooled bulk water coincides with the crossover to a predominantly low-density-like liquid below the Widom line TW. The frequency and onset temperature of the Boson peak in our simulations of bulk water agree well with the results from experiments on nanoconfined water. Our results suggest that the Boson peak in water is not an exclusive effect of confinement. We further find that, similar to other glass-forming liquids, the vibrational modes corresponding to the Boson peak are spatially extended and are related to transverse phonons found in the parent crystal, here ice Ih. PMID:23771033

  3. Weld peaking on heavy aluminum structures

    NASA Technical Reports Server (NTRS)

    Bayless, E.; Poorman, R.; Sexton, J.

    1978-01-01

    Weld peaking is usually undesirable in any welded structure. In heavy structures, the forces involved in the welding process become very large and difficult to handle. With the shuttle's solid rocket booster, the weld peaking resulted in two major problems: (1) reduced mechanical properties across the weld joint, and (2) fit-up difficulties in subsequent assembly operation. Peaking from the weld shrinkage forces can be fairly well predicted in simple structures; however, in welding complicated assemblies, the amount of peaking is unpredictable because of unknown stresses from machining and forming, stresses induced by the fixturing, and stresses from welds in other parts of the assembly. When excessive peaking is encountered, it can be corrected using the shrinkage forces resulting from the welding process. Application of these forces is discussed in this report.

  4. Multiscale peak alignment for chromatographic datasets.

    PubMed

    Zhang, Zhi-Min; Liang, Yi-Zeng; Lu, Hong-Mei; Tan, Bin-Bin; Xu, Xiao-Na; Ferro, Miguel

    2012-02-01

    Chromatography has been extensively applied in many fields, such as metabolomics and quality control of herbal medicines. Preprocessing, especially peak alignment, is a time-consuming task prior to the extraction of useful information from the datasets by chemometrics and statistics. To accurately and rapidly align shift peaks among one-dimensional chromatograms, multiscale peak alignment (MSPA) is presented in this research. Peaks of each chromatogram were detected based on continuous wavelet transform (CWT) and aligned against a reference chromatogram from large to small scale gradually, and the aligning procedure is accelerated by fast Fourier transform cross correlation. The presented method was compared with two widely used alignment methods on chromatographic dataset, which demonstrates that MSPA can preserve the shapes of peaks and has an excellent speed during alignment. Furthermore, MSPA method is robust and not sensitive to noise and baseline. MSPA was implemented and is available at http://code.google.com/p/mspa. PMID:22222564

  5. Multiscale peak detection in wavelet space.

    PubMed

    Zhang, Zhi-Min; Tong, Xia; Peng, Ying; Ma, Pan; Zhang, Ming-Jin; Lu, Hong-Mei; Chen, Xiao-Qing; Liang, Yi-Zeng

    2015-12-01

    Accurate peak detection is essential for analyzing high-throughput datasets generated by analytical instruments. Derivatives with noise reduction and matched filtration are frequently used, but they are sensitive to baseline variations, random noise and deviations in the peak shape. A continuous wavelet transform (CWT)-based method is more practical and popular in this situation, which can increase the accuracy and reliability by identifying peaks across scales in wavelet space and implicitly removing noise as well as the baseline. However, its computational load is relatively high and the estimated features of peaks may not be accurate in the case of peaks that are overlapping, dense or weak. In this study, we present multi-scale peak detection (MSPD) by taking full advantage of additional information in wavelet space including ridges, valleys, and zero-crossings. It can achieve a high accuracy by thresholding each detected peak with the maximum of its ridge. It has been comprehensively evaluated with MALDI-TOF spectra in proteomics, the CAMDA 2006 SELDI dataset as well as the Romanian database of Raman spectra, which is particularly suitable for detecting peaks in high-throughput analytical signals. Receiver operating characteristic (ROC) curves show that MSPD can detect more true peaks while keeping the false discovery rate lower than MassSpecWavelet and MALDIquant methods. Superior results in Raman spectra suggest that MSPD seems to be a more universal method for peak detection. MSPD has been designed and implemented efficiently in Python and Cython. It is available as an open source package at . PMID:26514234

  6. Atmospheric Solar Heating in Minor Absorption Bands

    NASA Technical Reports Server (NTRS)

    Chou, Ming-Dah

    1998-01-01

    Solar radiation is the primary source of energy driving atmospheric and oceanic circulations. Concerned with the huge computing time required for computing radiative transfer in weather and climate models, solar heating in minor absorption bands has often been neglected. The individual contributions of these minor bands to the atmospheric heating is small, but collectively they are not negligible. The solar heating in minor bands includes the absorption due to water vapor in the photosynthetically active radiation (PAR) spectral region from 14284/cm to 25000/cm, the ozone absorption and Rayleigh scattering in the near infrared, as well as the O2 and CO2 absorption in a number of weak bands. Detailed high spectral- and angular-resolution calculations show that the total effect of these minor absorption is to enhance the atmospheric solar heating by approximately 10%. Depending upon the strength of the absorption and the overlapping among gaseous absorption, different approaches are applied to parameterize these minor absorption. The parameterizations are accurate and require little extra time for computing radiative fluxes. They have been efficiently implemented in the various atmospheric models at NASA/Goddard Space Flight Center, including cloud ensemble, mesoscale, and climate models.

  7. Gas-absorption process

    DOEpatents

    Stephenson, Michael J.; Eby, Robert S.

    1978-01-01

    This invention is an improved gas-absorption process for the recovery of a desired component from a feed-gas mixture containing the same. In the preferred form of the invention, the process operations are conducted in a closed-loop system including a gas-liquid contacting column having upper, intermediate, and lower contacting zones. A liquid absorbent for the desired component is circulated through the loop, being passed downwardly through the column, regenerated, withdrawn from a reboiler, and then recycled to the column. A novel technique is employed to concentrate the desired component in a narrow section of the intermediate zone. This technique comprises maintaining the temperature of the liquid-phase input to the intermediate zone at a sufficiently lower value than that of the gas-phase input to the zone to effect condensation of a major part of the absorbent-vapor upflow to the section. This establishes a steep temperature gradient in the section. The stripping factors below this section are selected to ensure that virtually all of the gases in the downflowing absorbent from the section are desorbed. The stripping factors above the section are selected to ensure re-dissolution of the desired component but not the less-soluble diluent gases. As a result, a peak concentration of the desired component is established in the section, and gas rich in that component can be withdrawn therefrom. The new process provides important advantages. The chief advantage is that the process operations can be conducted in a single column in which the contacting zones operate at essentially the same pressure.

  8. PeakRanger: A cloud-enabled peak caller for ChIP-seq data

    PubMed Central

    2011-01-01

    Background Chromatin immunoprecipitation (ChIP), coupled with massively parallel short-read sequencing (seq) is used to probe chromatin dynamics. Although there are many algorithms to call peaks from ChIP-seq datasets, most are tuned either to handle punctate sites, such as transcriptional factor binding sites, or broad regions, such as histone modification marks; few can do both. Other algorithms are limited in their configurability, performance on large data sets, and ability to distinguish closely-spaced peaks. Results In this paper, we introduce PeakRanger, a peak caller software package that works equally well on punctate and broad sites, can resolve closely-spaced peaks, has excellent performance, and is easily customized. In addition, PeakRanger can be run in a parallel cloud computing environment to obtain extremely high performance on very large data sets. We present a series of benchmarks to evaluate PeakRanger against 10 other peak callers, and demonstrate the performance of PeakRanger on both real and synthetic data sets. We also present real world usages of PeakRanger, including peak-calling in the modENCODE project. Conclusions Compared to other peak callers tested, PeakRanger offers improved resolution in distinguishing extremely closely-spaced peaks. PeakRanger has above-average spatial accuracy in terms of identifying the precise location of binding events. PeakRanger also has excellent sensitivity and specificity in all benchmarks evaluated. In addition, PeakRanger offers significant improvements in run time when running on a single processor system, and very marked improvements when allowed to take advantage of the MapReduce parallel environment offered by a cloud computing resource. PeakRanger can be downloaded at the official site of modENCODE project: http://www.modencode.org/software/ranger/ PMID:21554709

  9. Geological study of uranium potential of the Kingston Peak Formation, Death Valley Region, California

    SciTech Connect

    Carlisle, D.; Kettler, R.M.; Swanson, S.C.

    1980-09-01

    The results of a geological survey of the Kingston Peak Formation on the western slope of the Panamint Range near Death Valley are discussed. The geology of the Panamint mountains was mapped on topographic base maps of the Telescope Peak and Manly Peak quadrangles. Radiometric suveys of the area were conducted using gamma ray spectrometers. Samples of the conglomerate were analyzed using delayed neutron, neutron activation, atomic absorption, and LECO analysis. It is concluded that uranium mineralization in the Favorable Submember is significant and further exploration is warranted. The monazite-fenotime related uranium and thorium mineralization in the Mountain Girl quartz pebble conglomerate is of no economic interest. (DMC)

  10. Analysis of thermoluminescent glow peaks of zoisite under beta irradiations

    SciTech Connect

    Ccallata, Henry Javier; Watanabe, Shigueo

    2010-08-04

    In this study, the thermoluminescence (TL) properties of natural crystal of zoisite were investigated after beta ({sup 90}Sr) irradiation at room temperature (RT). Zoisite, of chemical formula Ca{sub 2}Al{sub 3}(SiO{sub 4})(Si{sub 2}O{sub 7})O(OH), is found in Minas Gerais State, Brazil as natural mineral of silicate, member of the epidote group. The glow curve of a natural sample submitted to a heat treatment at 600 deg. C is composed of two broad peaks, centered at about 110-130 deg. C and another one at about 205-210 deg. C. A heating rate of 4 deg. C s{sup -1} was used in the temperature range from RT to 300 deg. C. The additive dose, T{sub m}-T{sub STOP} thermal cleaning, initial rise, variable heating rate and computerized glow curve deconvolution methods have shown that the glow curve is a superposition of six peaks at 100, 130, 155, 175, 200 and 230 deg. C. The trapping parameters for the individual peaks have been calculated. The TL dose response of 130 and 200 deg. C peaks has a linear response. Zoisite is a candidate for a TL dosimeter because of its high sensitivity.

  11. Cross-peak-specific two-dimensional electronic spectroscopy

    PubMed Central

    Read, Elizabeth L.; Engel, Gregory S.; Calhoun, Tessa R.; Mančal, Tomáš; Ahn, Tae Kyu; Blankenship, Robert E.; Fleming, Graham R.

    2007-01-01

    Intermolecular electronic coupling dictates the optical properties of molecular aggregate systems. Of particular interest are photosynthetic pigment–protein complexes that absorb sunlight then efficiently direct energy toward the photosynthetic reaction center. Two-dimensional (2D) ultrafast spectroscopy has been used widely in the infrared (IR) and increasingly in the visible to probe excitonic couplings and observe dynamics, but the off-diagonal spectral signatures of coupling are often obscured by broad diagonal peaks, especially in the visible regime. Rotating the polarizations of the laser pulses exciting the sample can highlight certain spectral features, and the use of polarized pulse sequences to elucidate cross-peaks in 2D spectra has been demonstrated in the IR for vibrational transitions. Here we develop 2D electronic spectroscopy using cross-peak-specific pulse polarization conditions in an investigation of the Fenna–Matthews–Olson light harvesting complex from green photosynthetic bacteria. Our measurements successfully highlight off-diagonal features of the 2D spectra and, in combination with an analysis based on the signs of features arising from particular energy level pathways and theoretical simulation, we characterize the dominant response pathways responsible for the spectral features. Cross-peak-specific 2D electronic spectroscopy provides insight into the interchromophore couplings, as well as into the energetic pathways giving rise to the signal. With femtosecond resolution, we also observe dynamical processes that depend on these couplings and interactions with the protein environment. PMID:17548830

  12. Transient radiation-induced absorption at 1061 nm in LiNiO[sub 3] and MgO:LiNbO[sub 3

    SciTech Connect

    Brannon, P.J. )

    1994-06-01

    The transient radiation-induced 1061 nm absorption in pure and MgO doped lithium niobate has been measured using Sandia National Laboratories' SPR 3 pulsed nuclear reactor. The samples are subjected to neutron fluences up to 10[sup 13]/cm[sup 2] (1 MeV Si) and total doses up to 7.5 krad. By using various shields, it has been found that gamma rays are the major contributors to the induced absorption at this wavelength. A plot of the natural logarithm of the transmittance versus time is given along with the peak induced absorption coefficient versus dose. The data indicate color centers with different time dependencies. A log-log plot of the transmission loss in dB/cm versus time indicates a 1/t[sup 1/4] time dependence initially.

  13. FIRST SPECTROSCOPIC IDENTIFICATION OF MASSIVE YOUNG STELLAR OBJECTS IN THE GALACTIC CENTER

    SciTech Connect

    An, Deokkeun; Boogert, A. C. Adwin; RamIrez, Solange V.; Sellgren, Kris; Arendt, Richard G.; Stolovy, Susan R.; Cotera, Angela S.; Robitaille, Thomas P.; Smith, Howard A. E-mail: sellgren@astronomy.ohio-state.edu

    2009-09-10

    We report the detection of several molecular gas-phase and ice absorption features in three photometrically selected young stellar object (YSO) candidates in the central 280 pc of the Milky Way. Our spectra, obtained with the Infrared Spectrograph (IRS) onboard the Spitzer Space Telescope, reveal gas-phase absorption from CO{sub 2} (15.0 {mu}m), C{sub 2}H{sub 2} (13.7 {mu}m), and HCN (14.0 {mu}m). We attribute this absorption to warm, dense gas in massive YSOs. We also detect strong and broad 15 {mu}m CO{sub 2} ice absorption features, with a remarkable double-peaked structure. The prominent long-wavelength peak is due to CH{sub 3}OH-rich ice grains, and is similar to those found in other known massive YSOs. Our IRS observations demonstrate the youth of these objects, and provide the first spectroscopic identification of massive YSOs in the Galactic Center.

  14. Linear and nonlinear optical absorption coefficients of spherical dome shells

    NASA Astrophysics Data System (ADS)

    Guo, Kangxian; Liu, Guanghui; Huang, Lu; Zheng, Xianyi

    2015-08-01

    Linear and nonlinear optical absorption coefficients of spherical dome shells are theoretically investigated within analytical wave functions and numerical quantized energy levels. Our results show that the inner radius, the outer radius and the cut-off angle of spherical dome shells have great influences on linear and nonlinear optical absorption coefficients as well as the total optical absorption coefficients. It is found that with the increase of the inner radius and the outer radius, linear and nonlinear optical absorption coefficients exhibit a blueshift and a redshift, respectively. However, with the increase of the cut-off angle, linear and nonlinear optical absorption coefficients do not shift. Besides, the resonant peaks of linear and nonlinear optical absorption coefficients climb up and then decrease with increasing the cut-off angle. The influences of the incident optical intensity on the total optical absorption coefficients are studied. It is found that the bleaching effect occurs at higher incident optical intensity.

  15. Saving Power at Peak Hours (LBNL Science at the Theater)

    ScienceCinema

    Piette, Mary Ann

    2011-04-28

    California needs new, responsive, demand-side energy technologies to ensure that periods of tight electricity supply on the grid don't turn into power outages. Led by Berkeley Lab's Mary Ann Piette, the California Energy Commission (through its Public Interest Energy Research Program) has established a Demand Response Research Center that addresses two motivations for adopting demand responsiveness: reducing average electricity prices and preventing future electricity crises. The research seeks to understand factors that influence "what works" in Demand Response. Piette's team is investigating the two types of demand response, load response and price response, that may influence and reduce the use of peak electric power through automated controls, peak pricing, advanced communications, and other strategies.

  16. Peaks theory and the excursion set approach

    NASA Astrophysics Data System (ADS)

    Paranjape, Aseem; Sheth, Ravi K.

    2012-11-01

    We describe a model of dark matter halo abundances and clustering which combines the two most widely used approaches to this problem: that based on peaks and the other based on excursion sets. Our approach can be thought of as addressing the cloud-in-cloud problem for peaks and/or modifying the excursion set approach so that it averages over a special subset, rather than all possible walks. In this respect, it seeks to account for correlations between steps in the walk as well as correlations between walks. We first show how the excursion set and peaks models can be written in the same formalism, and then use this correspondence to write our combined excursion set peaks model. We then give simple expressions for the mass function and bias, showing that even the linear halo bias factor is predicted to be k-dependent as a consequence of the non-locality associated with the peak constraint. At large masses, our model has little or no need to rescale the variable δc from the value associated with spherical collapse, and suggests a simple explanation for why the linear halo bias factor appears to lie above that based on the peak-background split at high masses when such a rescaling is assumed. Although we have concentrated on peaks, our analysis is more generally applicable to other traditionally single-scale analyses of large-scale structure.

  17. Effect of migraine attacks on paracetamol absorption.

    PubMed Central

    Tokola, R A; Neuvonen, P J

    1984-01-01

    The absorption of effervescent paracetamol (1000 mg) was investigated in nine female patients during a migraine attack and in the same patients when headache free. Migraine attack decreased (P less than 0.05) the areas under the serum paracetamol concentration-time curves (AUC) of 0-2 h, 0-4 h and 0-6 h and the peak serum concentration. The severity of nausea correlated significantly with the decrease in the AUC values. Our results support findings of delayed gastric emptying in migraine attacks. Both a delay and an impairment of drug absorption may follow. PMID:6529526

  18. Dust-on-snow and the timing of peak streamflow in the upper Rio Grande

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dust radiative forcing on high elevation snowpack is well-documented in the southern Rockies. Various field studies show that dust deposits decrease snow albedo and increase absorption of solar radiation, leading to earlier snowmelt and peak stream flows. These findings have implications for the use...

  19. Radiation-induced transmission loss in low water peak single mode fibers

    NASA Astrophysics Data System (ADS)

    Wang, Tingyun; Xiao, Zhongyin; Luo, Wenyun; Wen, Jianxiang; Yin, Jianchong; Wu, Wenkai; Gong, Renxiang

    2013-12-01

    Radiation-induced transmission loss in Low Water Peak Single Mode (LWPSM) fiber has been investigated. Formation and conversion processes of defect centers also have been proposed using electron spin resonance in the fiber irradiated with gamma rays. When the irradiation dose is low, Germanium electron center (GEC) and self-trapped hole center (STH) occur. With the increase of dose, E' centers (Si and Ge) and nonbridge oxygen hole centers (NBOHCs) generate. With the help of thermal-bleaching or photo-bleaching, the radiation-induced loss of pre-irradiation optical fiber can be reduced effectively. The obtain results also have been analyzed in detail.

  20. In Brief: Timing of peak oil uncertain

    NASA Astrophysics Data System (ADS)

    Zielinski, Sarah

    2007-04-01

    According to the Hubbert peak theory, oil production in any geographic area will follow a bellshaped curve. The timing of the `peak' in global oil production is important because after that point, there will be less and less oil available for consumption. A new report from the U.S. Government Accountability Office found that most studies estimate that peak oil production will occur sometime between now and 2040. The uncertainty in these estimates could be reduced with better information about worldwide supply and demand, and alternative fuels and transportation technologies could mitigate the effects of a global decline in oil production. However, the report found no coordinated U.S. federal strategy to address these issues. The report, ``Uncertainty about Future Oil Supply Makes It Important to Develop a Strategy for Addressing a Peak and Decline in Oil Production,'' is available at http://www.gao.gov/cgi-bin/getrpt?GAO-07-283

  1. Reducing Peak Demand by Time Zone Divisions

    NASA Astrophysics Data System (ADS)

    Chakrabarti, A.

    2014-09-01

    For a large country like India, the electrical power demand is also large and the infrastructure cost for power is the largest among all the core sectors of economy. India has an emerging economy which requires high rate of growth of infrastructure in the power generation, transmission and distribution. The current peak demand in the country is approximately 1,50,000 MW which shall have a planned growth of at least 50 % over the next five years (Seventeenth Electric Power Survey of India, Central Electricity Authority, Government of India, March 2007). By implementing the time zone divisions each comprising of an integral number of contiguous states based on their total peak demand and geographical location, the total peak demand of the nation can be significantly cut down by spreading the peak demand of various states over time. The projected reduction in capital expenditure over a plan period of 5 years is substantial. Also, the estimated reduction in operations expenditure cannot be ignored.

  2. Flu Season Hasn't Peaked Yet

    MedlinePlus

    ... nlm.nih.gov/medlineplus/news/fullstory_157852.html Flu Season Hasn't Peaked Yet This year's vaccine ... 2016 FRIDAY, March 18, 2016 (HealthDay News) -- This flu season continues to be the mildest in the ...

  3. Observing at Kitt Peak National Observatory.

    ERIC Educational Resources Information Center

    Cohen, Martin

    1981-01-01

    Presents an abridged version of a chapter from the author's book "In Quest of Telescopes." Includes personal experiences at Kitt Peak National Observatory, and comments on telescopes, photographs, and making observations. (SK)

  4. Helping System Engineers Bridge the Peaks

    NASA Technical Reports Server (NTRS)

    Rungta, Neha; Tkachuk, Oksana; Person, Suzette; Biatek, Jason; Whalen, Michael W.; Castle, Joseph; Castle, JosephGundy-Burlet, Karen

    2014-01-01

    In our experience at NASA, system engineers generally follow the Twin Peaks approach when developing safety-critical systems. However, iterations between the peaks require considerable manual, and in some cases duplicate, effort. A significant part of the manual effort stems from the fact that requirements are written in English natural language rather than a formal notation. In this work, we propose an approach that enables system engineers to leverage formal requirements and automated test generation to streamline iterations, effectively "bridging the peaks". The key to the approach is a formal language notation that a) system engineers are comfortable with, b) is supported by a family of automated V&V tools, and c) is semantically rich enough to describe the requirements of interest. We believe the combination of formalizing requirements and providing tool support to automate the iterations will lead to a more efficient Twin Peaks implementation at NASA.

  5. Light Absorption in Arctic Sea Ice - Black Carbon vs Chlorophyll

    NASA Astrophysics Data System (ADS)

    Ogunro, O. O.; Wingenter, O. W.; Elliott, S.; Hunke, E. C.; Flanner, M.; Wang, H.; Dubey, M. K.; Jeffery, N.

    2015-12-01

    The fingerprint of climate change is more obvious in the Arctic than any other place on Earth. This is not only because the surface temperature there has increased at twice the rate of global mean temperature but also because Arctic sea ice extent has reached a record low of 49% reduction relative to the 1979-2000 climatology. Radiation absorption through black carbon (BC) deposited on Arctic snow and sea ice surface is one of the major hypothesized contributors to the decline. However, we note that chlorophyll-a absorption owing to increasing biology activity in this region could be a major competitor during boreal spring. Modeling of sea-ice physical and biological processes together with experiments and field observations promise rapid progress in the quality of Arctic ice predictions. Here we develop a dynamic ice system module to investigate discrete absorption of both BC and chlorophyll in the Arctic, using BC deposition fields from version 5 of Community Atmosphere Model (CAM5) and vertically distributed layers of chlorophyll concentrations from Sea Ice Model (CICE). To this point, our black carbon mixing ratios compare well with available in situ data. Both results are in the same order of magnitude. Estimates from our calculations show that sea ice and snow around the Canadian Arctic Archipelago and Baffin Bay has the least black carbon absorption while values at the ice-ocean perimeter in the region of the Barents Sea peak significantly. With regard to pigment concentrations, high amounts of chlorophyll are produced in Arctic sea ice by the bottom microbial community, and also within the columnar pack wherever substantial biological activity takes place in the presence of moderate light. We show that the percentage of photons absorbed by chlorophyll in the spring is comparable to the amount attributed to BC, especially in areas where the total deposition rates are decreasing with time on interannual timescale. We expect a continuous increase in

  6. Probing the influence of the center atom coordination structure in iron phthalocyanine multi-walled carbon nanotube-based oxygen reduction reaction catalysts by X-ray absorption fine structure spectroscopy

    NASA Astrophysics Data System (ADS)

    Peng, Yingxiang; Li, Zhipan; Xia, Dingguo; Zheng, Lirong; Liao, Yi; Li, Kai; Zuo, Xia

    2015-09-01

    Three different pentacoordinate iron phthalocyanine (FePc) electrocatalysts with an axial ligand (pyridyl group, Py) anchored to multi-walled carbon nanotubes (MWCNTs) are prepared by a microwave method as high performance composite electrocatalysts (FePc-Py/MWCNTs) for the oxygen reduction reaction (ORR). For comparison, tetracoordinate FePc electrocatalysts without an axial ligand anchored to MWCNTs (FePc/MWCNTs) are assembled in the same way. Ultraviolet-visible spectrophotometry (UV-Vis), Raman spectroscopy (RS), and high-resolution transmission electron microscopy (HRTEM) are used to characterize the obtained electrocatalysts. The electrocatalytic activity of the samples is measured by linear sweep voltammetry (LSV), and the onset potential of all of the FePc-Py/MWCNTs electrocatalysts is found to be more positive than that of their FePc/MWCNTs counterparts. X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) spectroscopy are employed to elucidate the relationship between molecular structure and electrocatalytic activity. XPS indicates that higher concentrations of Fe3+ and pyridine-type nitrogen play critical roles in determining the electrocatalytic ORR activity of the samples. XAFS spectroscopy reveals that the FePc-Py/MWCNTs electrocatalysts have a coordination geometry around Fe that is closer to the square pyramidal structure, a higher concentration of Fe3+, and a smaller phthalocyanine ring radius compared with those of FePc/MWCNTs.

  7. The binuclear nickel center in the A-cluster of acetyl-CoA synthase (ACS) and two biomimetic dinickel complexes studied by X-ray absorption and emission spectroscopy

    NASA Astrophysics Data System (ADS)

    Schrapers, P.; Mebs, S.; Ilina, Y.; Warner, D. S.; Wörmann, C.; Schuth, N.; Kositzki, R.; Dau, H.; Limberg, C.; Dobbek, H.; Haumann, M.

    2016-05-01

    Acetyl-CoA synthase (ACS) is involved in the bacterial carbon oxide conversion pathway. The binuclear nickel sites in ACS enzyme and two biomimetic synthetic compounds containing a Ni(II)Ni(II) unit (1 and 2) were compared using XAS/XES. EXAFS analysis of ACS proteins revealed similar Ni-N/O/S bond lengths and Ni-Ni/Fe distances as in the crystal structure in oxidized ACS, but elongated Ni-ligand bonds in reduced ACS, suggesting more reduced nickel species. The XANES spectra of ACS and the dinickel complexes showed overall similar shapes, but less resolved pre-edge and edge features in ACS, attributed to more distorted square-planar nickel sites in particular in reduced ACS. DFT calculation of pre-edge absorption and Kβ2,5 emission features reproduced the experimental spectra of the synthetic complexes, was sensitive even to the small geometry differences in 1 and 2, and indicated low-spin Ni(II) sites. Comparison of nickel sites in proteins and biomimetic compounds is valuable for deducing structural and electronic differences in response to ligation and redox changes.

  8. Forward-peaked scattering of polarized light.

    PubMed

    Clark, Julia P; Kim, Arnold D

    2014-11-15

    Polarized light propagation in a multiple scattering medium is governed by the vector radiative transfer equation. We analyze the vector radiative transfer equation in asymptotic limit of forward-peaked scattering and derive an approximate system of equations for the Stokes parameters, which we call the vector Fokker-Planck approximation. The vector Fokker-Planck approximation provides valuable insight into several outstanding issues regarding the forward-peaked scattering of polarized light such as the polarization memory phenomenon. PMID:25490484

  9. Cosmic microwave background acoustic peak locations

    NASA Astrophysics Data System (ADS)

    Pan, Z.; Knox, L.; Mulroe, B.; Narimani, A.

    2016-07-01

    The Planck collaboration has measured the temperature and polarization of the cosmic microwave background well enough to determine the locations of eight peaks in the temperature (TT) power spectrum, five peaks in the polarization (EE) power spectrum and 12 extrema in the cross (TE) power spectrum. The relative locations of these extrema give a striking, and beautiful, demonstration of what we expect from acoustic oscillations in the plasma; e.g. that EE peaks fall half way between TT peaks. We expect this because the temperature map is predominantly sourced by temperature variations in the last scattering surface, while the polarization map is predominantly sourced by gradients in the velocity field, and the harmonic oscillations have temperature and velocity 90 deg out of phase. However, there are large differences in expectations for extrema locations from simple analytic models versus numerical calculations. Here, we quantitatively explore the origin of these differences in gravitational potential transients, neutrino free-streaming, the breakdown of tight coupling, the shape of the primordial power spectrum, details of the geometric projection from three to two dimensions, and the thickness of the last scattering surface. We also compare the peak locations determined from Planck measurements to expectations under the Λ cold dark matter model. Taking into account how the peak locations were determined, we find them to be in agreement.

  10. Peak Effect in High-Tc Superconductors

    NASA Astrophysics Data System (ADS)

    Ling, Xinsheng

    1996-03-01

    Like many low-Tc superconductors, high-quality YBCO single crystals are found(X.S. Ling and J.I. Budnick, in Magnetic Susceptibility of Superconductors and Other Spin Systems), edited by R.A. Hein, T.L. Francavilla, and D.H. Liebenberg (Plenum Press, New York, 1991), p.377. to exhibit a striking peak effect. In a magnetic field, the temperature dependence of the critical current has a pronounced peak below T_c(H). Pippard(A.B. Pippard, Phil. Mag. 19), 217 (1969)., and subsequently Larkin and Ovchinnikov(A.I. Larkin and Yu.N. Ovchinnikov, J. Low Temp. Phys. 34), 409 (1979)., attributed the onset of the peak effect to a softening of the vortex lattice. In this talk, the experimental discovery^1 of the peak effect in high-Tc superconductors will be described, followed by a brief historical perspective of the understanding of this phenomenon and a discussion of a new model(X.S. Ling, C. Tang, S. Bhattacharya, and P.M. Chaikin, cond-mat/9504109, (NEC Preprint 1995).) for the peak effect. In this model, the peak effect is an interesting manifestation of the vortex-lattice melting in the presence of weak random pinning potentials. The rise of critical current with increasing temperature is a signature of the ``melting'' of the Larkin domains. This work is done in collaboration with Joe Budnick, Chao Tang, Shobo Bhattacharya, Paul Chaikin, and Boyd Veal.

  11. Hastings Center

    MedlinePlus

    ... Events October 19, Hastings Center Seminar, Garrison : Human Genetic Engineering: Wh at Can We Do? What Should We ... Events October 19, Hastings Center Seminar, Garrison : Human Genetic Engineering: Wh at Can We Do? What Should We ...

  12. Origin of the first sharp diffraction peak in glasses

    NASA Astrophysics Data System (ADS)

    Crupi, Cristina; Carini, Giuseppe; González, Miguel; D'Angelo, Giovanna

    2015-10-01

    Although glasses have been largely used for a wide variety of technological applications, much of their underlying structure and dynamical properties remain puzzling. We present a detailed investigation of the intermediate-range structure of a series of alkaline borate glasses carried out by performing neutron diffraction measurements. We propose that the first sharp diffraction peak of glasses arises from the periodicity of the boundaries of voids in a random network and explain its compositional and pressure dependence. In this framework, the planar section of a void is an n -membered ring of all-side vertex sharing basic structural units. Furthermore, we suggest that thermally activated relaxations responsible for the ultrasonic absorption in borate glasses stem from transverse motions of atoms bridging structural units confining voids.

  13. Predicting Peak Flows following Forest Fires

    NASA Astrophysics Data System (ADS)

    Elliot, William J.; Miller, Mary Ellen; Dobre, Mariana

    2016-04-01

    Following forest fires, peak flows in perennial and ephemeral streams often increase by a factor of 10 or more. This increase in peak flow rate may overwhelm existing downstream structures, such as road culverts, causing serious damage to road fills at stream crossings. In order to predict peak flow rates following wildfires, we have applied two different tools. One is based on the U.S.D.A Natural Resource Conservation Service Curve Number Method (CN), and the other is by applying the Water Erosion Prediction Project (WEPP) to the watershed. In our presentation, we will describe the science behind the two methods, and present the main variables for each model. We will then provide an example of a comparison of the two methods to a fire-prone watershed upstream of the City of Flagstaff, Arizona, USA, where a fire spread model was applied for current fuel loads, and for likely fuel loads following a fuel reduction treatment. When applying the curve number method, determining the time to peak flow can be problematic for low severity fires because the runoff flow paths are both surface and through shallow lateral flow. The WEPP watershed version incorporates shallow lateral flow into stream channels. However, the version of the WEPP model that was used for this study did not have channel routing capabilities, but rather relied on regression relationships to estimate peak flows from individual hillslope polygon peak runoff rates. We found that the two methods gave similar results if applied correctly, with the WEPP predictions somewhat greater than the CN predictions. Later releases of the WEPP model have incorporated alternative methods for routing peak flows that need to be evaluated.

  14. The OH - absorption spectra of low doped lithium niobate crystals

    NASA Astrophysics Data System (ADS)

    Kong, Yongfa; Zhang, Wanlin; Xu, Jingjun; Yan, Wenbo; Liu, Hongde; Xie, Xiang; Li, Xiaochun; Shi, Lihong; Zhang, Guangyin

    2004-07-01

    The OH - absorption spectra of low doped lithium niobate (LiNbO 3) crystals have been investigated. Though no apparent band shift is observed in these absorption spectra, their shapes are quite different. In order to analyze the information on the defect structure underlying these OH - absorption bands, the normalization and difference methods were employed. It was found that although the doping concentrations are under the thresholds the doping ions have apparent affect to the site occupation of OH - ions. The OH - vibrations related to Mg Li+ (Mg 2+ occupying Li-site) and In Li2+ are 3483 and 3484 cm -1 in LiNbO 3:Mg and LiNbO 3:In crystals, respectively. The absorption peak of LiNbO 3:Ti (2.5 mol%) crystal at 3487 cm -1 is mainly related to Ti Li3+-OH - and the 3489 cm -1 peak of LiNbO 3:Mg (5.0 mol%), Ti (10.0 mol%) related to Mg Li+-OH -, Ti Nb--OH - and Ti Li3+-OH -. Doping with Na improves the peak intensity near 3466 cm -1 and induces a new absorption peak at 3470 cm -1. The absorption bands of LiNbO 3 crystals codoped with trivalent ions are associated with the co-effect of the doped ions and have some different characteristics from mono-doped crystals.

  15. Soft X-Ray Absorption Spectroscopy of High-Abrasion-Furnace Carbon Black

    NASA Astrophysics Data System (ADS)

    Muramatsu, Yasuji; Harada, Ryusuke; Gullikson, Eric M.

    2007-02-01

    The soft x-ray absorption spectra of high-abrasion-furnace carbon black were measured to obtain local-structure/chemical-states information of the primary particles and/or crystallites. The soft x-ray absorption spectral features of carbon black represent broader π* and σ* peak structures compared to highly oriented pyrolytic graphite (HOPG). The subtracted spectra between the carbon black and HOPG, (carbon black) — (HOPG), show double-peak structures on both sides of the π* peak. The lower-energy peak, denoted as the "pre-peak", in the subtracted spectra and the π*/σ* peak intensity ratio in the absorption spectra clearly depend on the specific surface area by nitrogen adsorption (NSA). Therefore, it is concluded that the pre-peak intensity and the π*/σ* ratio reflect the local graphitic structure of carbon black.

  16. Absorption spectra of monolayer MoS2 in high magnetic field

    NASA Astrophysics Data System (ADS)

    Yang, Hung-Duen; Her, Jim-Long; Takeyama, Shojiro; Matsuda, Yasuhiro; Wang, Kai-Hsuan

    2015-03-01

    We have measured the absorption spectra of monolayer MoS2 film at several temperatures in pulsed high magnetic fields up to 52 T. At room temperature, the observed spectrum dominated by two main peaks, which are located at 660 nm and 606 nm. These peaks are ascribed to excition and trion absorption peaks respectively [1]. At low temperature (4.2 K), two peaks show the blue shift to 633 nm and 588 nm, respectively. Irrespective of the temperature, applying magnetic field does not show pronounced influence on the peaks even in 52 T.

  17. Job center

    NASA Astrophysics Data System (ADS)

    To better meet the needs of AGU members, a program has been started to increase the effectiveness of the Job Center activity at the Spring and Fall Meetings. As a result, participation in the Job Center at the 1988 AGU Spring Meeting in Baltimore increased substantially compared to previous Spring Meetings. The number of employers, applicants, and interviews scheduled more than doubled compared to the 1987 Spring Job Center.In order to make the meeting Job Centers even better, a survey is being conducted of employers and applicants who participated in the 1988 Spring Job Center. Evaluation of this survey will be useful in continuing increased participation in and the effectiveness of the Job Center at the 1988 Fall Meeting. Past participants and those interested in the future of the Job Center are encouraged to forward comments and suggestions to AGU, Member Programs Division, 2000 Florida Ave., N.W., Washington, DC 20009.

  18. Nasal peak inspiratory flow at altitude.

    PubMed

    Barry, P W; Mason, N P; Richalet, J P

    2002-01-01

    The present study investigated whether there are changes in nasal peak inspiratory flow (NPIF) during hypobaric hypoxia under controlled environmental conditions. During operation Everest III (COMEX '97), eight subjects ascended to a simulated altitude of 8,848 m in a hypobaric chamber. NPIF was recorded at simulated altitudes of 0 m, 5,000 m and 8,000 m. Oral peak inspiratory and expiratory flow (OPIF, OPEF) were also measured. Ambient air temperature and humidity were controlled. NPIF increased by a mean +/- SD of 16 +/- 12% from sea level to 8,000 m, whereas OPIF increased by 47 +/- 14%. NPIF rose by 0.085 +/- 0.03 L x s(-1) per kilometre of ascent (p<0.05), significantly less than the rise in OPIF and OPEF of 0.35 +/- 0.10 and 0.33 +/- 0.04 L x s(-1) per kilometre (p<0.0005). Nasal peak inspiratory flow rises with ascent to altitude. The rise in nasal peak inspiratory flow with altitude was far less than oral peak inspiratory flow and less than the predicted rise according to changes in air density. This suggests flow limitation at the nose, and occurs under controlled environmental conditions, refuting the hypothesis that nasal blockage at altitude is due to the inhalation of cold, dry air. Further work is needed to determine if nasal blockage limits activity at altitude. PMID:11843316

  19. X-ray absorption fine structure study of amorphous metal oxide thin films prepared by photochemical metalorganic deposition

    NASA Astrophysics Data System (ADS)

    Trudel, Simon; Daryl Crozier, E.; Gordon, Robert A.; Budnik, Peter S.; Hill, Ross H.

    2011-05-01

    The oxidation state and local geometry of the metal centers in amorphous thin films of Fe 2O 3 (Fe 3+ oxidation state), CoFe 2O 4 (Co 2+/Fe 3+ oxidation states), and Cr 2O 3 (Cr 3+ oxidation state) are determined using K edge X-ray absorption near-edge structure (XANES) spectroscopy and extended X-ray absorption fine structure (EXAFS) spectroscopy. The metal oxide thin films were prepared by the solid-state photochemical decomposition of the relevant metal 2-ethylhexanoates, spin cast as thin films. No peaks are observed in the X-ray diffraction patterns, indicating the metal oxides are X-ray amorphous. The oxidation state of the metals is determined from the edge position of the K absorption edges, and in the case of iron-containing samples, an analysis of the pre-edge peaks. In all cases, the EXAFS analysis indicates the first coordination shell consists of oxygen atoms in an octahedral geometry, with a second shell consisting of metals. No higher shells are observed beyond 3.5 Å for all samples, indicating the metal oxides are truly amorphous, consistent with X-ray diffraction results.

  20. SLR data screening; location of peak of data distribution

    NASA Technical Reports Server (NTRS)

    Sinclair, Andrew T.

    1993-01-01

    At the 5th Laser Ranging Instrumentation Workshop held at Herstmonceux in 1984, consideration was given to the formation of on-site normal points by laser stations, and an algorithm was formulated. The algorithm included a recommendation that an iterated 3.0 x rms rejection criterion should be used to screen the data, and that arithmetic means should be formed within the normal point bins of the retained data. From Sept. 1990 onwards, this algorithm and screening criterion have been brought into effect by various laser stations for forming on-site normal points, and small variants of the algorithm are used by most analysis centers for forming normal points from full-rate data, although the data screening criterion they use ranges from about 2.5 to 3.0 x rms. At the CSTG Satellite Laser Ranging (SLR) Subcommission, a working group was set up in Mar. 1991 to review the recommended screening procedure. This paper has been influenced by the discussions of this working group, although the views expressed are primarily those of this author. The main thrust of this paper is that, particularly for single photon systems, a more important issue than data screening is the determination of the peak of a data distribution and hence, the determination of the bias of the peak from the mean. Several methods of determining the peak are discussed.

  1. SPANISH PEAKS WILDERNESS STUDY AREA, COLORADO.

    USGS Publications Warehouse

    Budding, Karin E.; Kluender, Steven E.

    1984-01-01

    A geologic and geochemical investigation and a survey of mines and prospects were conducted to evaluate the mineral-resource potential of the Spanish Peaks Wilderness Study Area, Huerfano and Las Animas Counties, in south-central Colorado. Anomalous gold, silver, copper, lead, and zinc concentrations in rocks and in stream sediments from drainage basins in the vicinity of the old mines and prospects on West Spanish Peak indicate a substantiated mineral-resource potential for base and precious metals in the area surrounding this peak; however, the mineralized veins are sparse, small in size, and generally low in grade. There is a possibility that coal may underlie the study area, but it would be at great depth and it is unlikely that it would have survived the intense igneous activity in the area. There is little likelihood for the occurrence of oil and gas because of the lack of structural traps and the igneous activity.

  2. The PEAK experience in South Carolina

    SciTech Connect

    1998-11-01

    The PEAK Institute was developed to provide a linkage for formal (schoolteachers) and nonformal educators (extension agents) with agricultural scientists of Clemson University`s South Carolina Agricultural Experiment Station System. The goal of the Institute was to enable teams of educators and researchers to develop and provide PEAK science and math learning experiences related to relevant agricultural and environmental issues of local communities for both classroom and 4-H Club experiences. The Peak Institute was conducted through a twenty day residential Institute held in June for middle school and high school teachers who were teamed with an Extension agent from their community. These educators participated in hands-on, minds-on sessions conducted by agricultural researchers and Clemson University Cooperative Extension specialists. Participants were given the opportunity to see frontier science being conducted by scientists from a variety of agricultural laboratories.

  3. Solar absorption surface panel

    DOEpatents

    Santala, Teuvo J.

    1978-01-01

    A composite metal of aluminum and nickel is used to form an economical solar absorption surface for a collector plate wherein an intermetallic compound of the aluminum and nickel provides a surface morphology with high absorptance and relatively low infrared emittance along with good durability.

  4. Paleomagnetism of the Becker Peak stock

    NASA Astrophysics Data System (ADS)

    Miller, B. A.; Housen, B. A.

    2009-12-01

    Paleomagnetic studies of plutonic rocks, although subject to uncertainty due to lack of paleohorizontal control, can provide important constrains of patterns of regional deformation, and can play a role in evaluation of tectonic models and reconstructions. Many plutonic rocks of the Cascades have been well-studied via paleomagnetism, but there are many that lack robust data sets. One such pluton, the Beckler Peak stock, is a late Cretaceous tonalitic stock, with biotite and amphibole K-Ar ages of 93 to 82 Ma (Engels and Crowder, 1971, Yeats and Engels, 1971). The Beckler Peak stock is considered to be a companion body to the larger Mt. Stuart Batholith, but is separated from the Mt. Stuart Batholith by the Evergreen Fault. For this study five paleomagnetic sites were sampled from the Beckler Peak stock near Skykomish, Washington. After low temperature and thermal demagnetization site means were calculated for the four sites where at least two samples survived demagnetization. Unblocking temperatures were indicative of magnetite and hematite as the carriers of remanence. Two of the site means were disregarded due to anomalous directions likely due to sites being from very large slump blocks. The two acceptable site means, along with a Beckler Peak stock site mean from Beck and Noson (1972) and another from Housen et al. (2003) give a stock-wide mean of D = 3.8°, I = 41.9°, k = 32.9, and α95 = 16.2°. This direction is consistent with mean directions for the Mount Stuart batholith determined by Beck and Noson (1972), Beck et al. (1981), and Housen et al. (2003). This directional consistency supports an association between the Beckler Peak stock and the Mt. Stuart Batholith, or at least that these two plutonic bodies were emplaced in the same structural block, and that any post-magnetization deformation (such as rotation and/or tilt associated with the Evergreen Fault) between the Beckler Peak stock and the Mt. Stuart Batholith was minor.

  5. Petawatt laser absorption bounded

    PubMed Central

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-01-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials. PMID:24938656

  6. Petawatt laser absorption bounded

    NASA Astrophysics Data System (ADS)

    Levy, Matthew C.; Wilks, Scott C.; Tabak, Max; Libby, Stephen B.; Baring, Matthew G.

    2014-06-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top particle accelerators, ultrafast imaging systems and laser fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. Here using a relativistic Rankine-Hugoniot-like analysis, we show for the first time that f exhibits a theoretical maximum and minimum. These bounds constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials.

  7. MOSES AND DENNISON PEAK ROADLESS AREAS, CALIFORNIA.

    USGS Publications Warehouse

    Goldfarb, Richard J.; Lipton, David A.

    1984-01-01

    A mineral-resource survey was conducted in the Moses and Dennison Peak Roadless Areas, southeastern Sierra Nevada, California. One area within the Moses Roadless Area is classified as having substantiated mineral-resource potential for small base-metal skarn deposits. Additionally, geochemical data indicate probable potential for small base-metal skarn deposits from one locality within Dennison Peak Roadless Area and for small tungsten skarn deposits from a region within Moses Roadless Area. The geologic setting precludes the presence of energy resources.

  8. Percutaneous absorption of drugs.

    PubMed

    Wester, R C; Maibach, H I

    1992-10-01

    The skin is an evolutionary masterpiece of living tissue which is the final control unit for determining the local and systemic availability of any drug which must pass into and through it. In vivo in humans, many factors will affect the absorption of drugs. These include individual biological variation and may be influenced by race. The skin site of the body will also influence percutaneous absorption. Generally, those body parts exposed to the open environment (and to cosmetics, drugs and hazardous toxic substances) are most affected. Treating patients may involve single daily drug treatment or multiple daily administration. Finally, the body will be washed (normal daily process or when there is concern about skin decontamination) and this will influence percutaneous absorption. The vehicle of a drug will affect release of drug to skin. On skin, the interrelationships of this form of administration involve drug concentration, surface area exposed, frequency and time of exposure. These interrelationships determine percutaneous absorption. Accounting for all the drug administered is desirable in controlled studies. The bioavailability of the drug then is assessed in relationship to its efficacy and toxicity in drug development. There are methods, both quantitative and qualitative, in vitro and in vivo, for studying percutaneous absorption of drugs. Animal models are substituted for humans to determine percutaneous absorption. Each of these methods thus becomes a factor in determining percutaneous absorption because they predict absorption in humans. The relevance of these predictions to humans in vivo is of intense research interest. The most relevant determination of percutaneous absorption of a drug in humans is when the drug in its approved formulation is applied in vivo to humans in the intended clinical situation. Deviation from this scenario involves the introduction of variables which may alter percutaneous absorption. PMID:1296607

  9. Design of separately tunable terahertz two-peak absorber based on graphene

    NASA Astrophysics Data System (ADS)

    Zhang, Longhui; Hu, Fangrong; Xu, Xinlong; Wang, Yue'e.; Guo, Enze

    2016-06-01

    A separately tunable terahertz (THz) two-peak absorber based on graphene is presented. From bottom to top, the absorber contains four layers, i.e., gold reflector, graphene patch array, polyimide and metal split-ring resonator (SRR) array layer. The controlling voltage is applied between the reflector and two separated surface electrodes to tune the Fermi level of graphene. As a result, these two absorption peaks can be separately tuned by the controlling voltages. The finite integral technique (FIT) is used to study the absorption theory and modulation mechanism. The simulation results show that the absorption of low-frequency and that of high-frequency are 95.5% and 90.0%, respectively. And the maximum modulation depths of them are about 49% and 71%, respectively. Moreover, the absorber is insensitive to polarization and still has good absorption at large angle. The separately tunable THz two-peak absorber offers a new way for the development of frequency selective detectors working in the range of microwave, THz and infrared.

  10. Relationships between peak ground acceleration, peak ground velocity, and modified mercalli intensity in California

    USGS Publications Warehouse

    Wald, D.J.; Quitoriano, V.; Heaton, T.H.; Kanamori, H.

    1999-01-01

    We have developed regression relationships between Modified Mercalli Intensity (Imm) and peak ground acceleration (PGA) and velocity (PGV) by comparing horizontal peak ground motions to observed intensities for eight significant California earthquakes. For the limited range of Modified Mercalli intensities (Imm), we find that for peak acceleration with V ??? Imm ??? VIII, Imm = 3.66 log(PGA) - 1.66, and for peak velocity with V ??? Imm ??? IX, Imm = 3.47 log(PGV) + 2.35. From comparison with observed intensity maps, we find that a combined regression based on peak velocity for intensity > VII and on peak acceleration for intensity < VII is most suitable for reproducing observed Imm patterns, consistent with high intensities being related to damage (proportional to ground velocity) and with lower intensities determined by felt accounts (most sensitive to higher-frequency ground acceleration). These new Imm relationships are significantly different from the Trifunac and Brady (1975) correlations, which have been used extensively in loss estimation.

  11. Switching from "absorption within transparency" to "transparency within transparency" in an electromagnetically induced absorption dominated transition.

    PubMed

    Dahl, Katrin; Molella, Luca Spani; Rinkleff, Rolf-Hermann; Danzmann, Karsten

    2008-05-01

    The absorption of a resonant coupling laser driving a closed degenerate two-level system in an atomic cesium beam was investigated as a function of the detuning of a second laser probing the same transition. The measurements were performed for four different polarization combinations of the two laser beams. Except for the beams of counterrotating polarizations all coupling-laser absorption profiles showed "absorption within transparency," i.e., the absorption in the region around the two-photon resonance was smaller than the absorption corresponding to the one-photon transition induced by the coupling laser, and an extra absorption peak was observed on this curve at the two-photon resonance. With regard to the beams of counterrotating polarizations we observed a switch from absorption within transparency to "transparency within transparency" when the probe-laser power exceeded the constant coupling-laser power. In other words, the cesium ensemble became mostly transparent to the coupling-laser beam at the two-photon resonance. PMID:18451960

  12. Design method of planar vibration system for specified ratio of energy peaks

    NASA Astrophysics Data System (ADS)

    Kim, Jun Woo; Lee, Sungon; Choi, Yong Je

    2015-05-01

    The magnitudes of the resonant peaks should be considered in the design stage of any bandwidth-relevant applications to widen the working bandwidth. This paper presents a new design method for a planar vibration system that satisfies any desired ratio of peak magnitudes at target resonant frequencies. An important geometric property of a modal triangle formed from three vibration centers representing vibration modes is found. Utilizing the property, the analytical expressions for the vibration energy generated by external forces are derived in terms of the geometrical data of vibration centers. When any desired ratio of peak magnitudes is specified, the locations of the vibration centers are found from their analytical relations. The corresponding stiffness matrix can be determined and realized accordingly. The systematic design methods for direct- and base-excitation systems are developed, and one numerical example is presented to illustrate the proposed design method.

  13. Correlated peak relative light intensity and peak current in triggered lightning subsequent return strokes

    NASA Technical Reports Server (NTRS)

    Idone, V. P.; Orville, R. E.

    1985-01-01

    The correlation between peak relative light intensity L(R) and stroke peak current I(R) is examined for 39 subsequent return strokes in two triggered lightning flashes. One flash contained 19 strokes and the other 20 strokes for which direct measurements were available of the return stroke peak current at ground. Peak currents ranged from 1.6 to 21 kA. The measurements of peak relative light intensity were obtained from photographic streak recordings using calibrated film and microsecond resolution. Correlations, significant at better than the 0.1 percent level, were found for several functional relationships. Although a relation between L(R) and I(R) is evident in these data, none of the analytical relations considered is clearly favored. The correlation between L(R) and the maximum rate of current rise is also examined, but less correlation than between L(R) and I(R) is found. In addition, the peak relative intensity near ground is evaluated for 22 dart leaders, and a mean ratio of peak dart leader to peak return stroke relative light intensity was found to be 0.1 with a range of 0.02-0.23. Using two different methods, the peak current near ground in these dart leaders is estimated to range from 0.1 to 6 kA.

  14. Six Ways To Foster Peak Performance.

    ERIC Educational Resources Information Center

    Sevilla, Christine; Wells, Timothy D.

    1999-01-01

    Discusses six initiatives that organizations can support to ensure peak performance: individual knowledge portfolios; mentoring and apprenticeship relationships; electronic conferencing systems; organizational knowledge repository; community of practice; reward and recognition. Defines each initiative and describes how to make each one work in an…

  15. Avoiding the False Peaks in Correlation Discrimination

    SciTech Connect

    Awwal, A S

    2009-07-31

    Fiducials imprinted on laser beams are used to perform video image based alignment of the 192 laser beams in the National Ignition Facility (NIF) of Lawrence Livermore National Laboratory. In many video images, matched filtering is used to detect the location of these fiducials. Generally, the highest correlation peak is used to determine the position of the fiducials. However, when the signal to-be-detected is very weak compared to the noise, this approach totally breaks down. The highest peaks act as traps for false detection. The active target images used for automatic alignment in the National Ignition Facility are examples of such images. In these images, the fiducials of interest exhibit extremely low intensity and contrast, surrounded by high intensity reflection from metallic objects. Consequently, the highest correlation peaks are caused by these bright objects. In this work, we show how the shape of the correlation is exploited to isolate the valid matches from hundreds of invalid correlation peaks, and therefore identify extremely faint fiducials under very challenging imaging conditions.

  16. Hubbert's Peak: the Impending World oil Shortage

    NASA Astrophysics Data System (ADS)

    Deffeyes, K. S.

    2004-12-01

    Global oil production will probably reach a peak sometime during this decade. After the peak, the world's production of crude oil will fall, never to rise again. The world will not run out of energy, but developing alternative energy sources on a large scale will take at least 10 years. The slowdown in oil production may already be beginning; the current price fluctuations for crude oil and natural gas may be the preamble to a major crisis. In 1956, the geologist M. King Hubbert predicted that U.S. oil production would peak in the early 1970s.1 Almost everyone, inside and outside the oil industry, rejected Hubbert's analysis. The controversy raged until 1970, when the U.S. production of crude oil started to fall. Hubbert was right. Around 1995, several analysts began applying Hubbert's method to world oil production, and most of them estimate that the peak year for world oil will be between 2004 and 2008. These analyses were reported in some of the most widely circulated sources: Nature, Science, and Scientific American.2 None of our political leaders seem to be paying attention. If the predictions are correct, there will be enormous effects on the world economy. Even the poorest nations need fuel to run irrigation pumps. The industrialized nations will be bidding against one another for the dwindling oil supply. The good news is that we will put less carbon dioxide into the atmosphere. The bad news is that my pickup truck has a 25-gallon tank.

  17. Peak structural response to nonstationary random excitations

    NASA Technical Reports Server (NTRS)

    Shinozuka, M.; Yang, J.-N.

    1971-01-01

    Study establishes distribution function of peak response values, based on frequency interpretation. Excitations considered include impact loading on landing gears and aircraft gust loading. Because of relative severity of excitations, prediction of fatigue and maximum response characteristics is important part of task of structural analysis and design.

  18. Double-peak subauroral ion drifts (DSAIDs)

    NASA Astrophysics Data System (ADS)

    He, Fei; Zhang, Xiao-Xin; Wang, Wenbin; Chen, Bo

    2016-06-01

    This paper reports double-peak subauroral ion drifts (DSAIDs), which is unique subset of subauroral ion drifts (SAIDs). A statistical analysis has been carried out for the first time with a database of 454 DSAID events identified from Defense Meteorological Satellite Program observations from 1987 to 2012. Both case studies and statistical analyses show that the two velocity peaks of DSAIDs are associated with two ion temperature peaks and two region-2 field-aligned currents (R2-FACs) peaks in the midlatitude ionospheric trough located in the low-conductance subauroral region. DSAIDs are regional and vary significantly with magnetic local time. DSAIDs can evolve from/to SAIDs during their lifetimes, which are from several minutes to tens of minutes. Comparisons between the ionospheric parameters of DSAIDs and SAIDs indicate that double-layer region-2 field-aligned currents (R2-FACs) may be the main driver of DSAIDs. It is also found that DSAIDs happen during more disturbed conditions compared with SAIDs.

  19. Peak power scaling of thulium-doped ultrafast fiber laser systems

    NASA Astrophysics Data System (ADS)

    Gebhardt, Martin; Gaida, Christian; Stutzki, Fabian; Jauregui, Cesar; Limpert, Jens; Tünnermann, Andreas

    2015-03-01

    We investigate challenges for scaling the output peak power of thulium-doped fiber chirped-pulse amplification systems (FCPA) to and beyond the GW-level. A major limitation for reaching high peak powers in the 2 μm regime is the presence of strong water vapor absorption features that cause detrimental propagation effects in the spatial and the temporal domain. Based on the investigation and understanding of these effects mitigation strategies have been developed, that have been one of the keys to demonstrate a new record pulse peak power of more than 200 MW from a thulium-based ultrafast fiber laser. Future experiments can ultimately lead to a further increase of pulse peak power way beyond the GW-level.

  20. Quasar Absorption Studies

    NASA Technical Reports Server (NTRS)

    Mushotzky, Richard (Technical Monitor); Elvis, Martin

    2004-01-01

    The aim of the proposal is to investigate the absorption properties of a sample of inter-mediate redshift quasars. The main goals of the project are: Measure the redshift and the column density of the X-ray absorbers; test the correlation between absorption and redshift suggested by ROSAT and ASCA data; constrain the absorber ionization status and metallicity; constrain the absorber dust content and composition through the comparison between the amount of X-ray absorption and optical dust extinction. Unanticipated low energy cut-offs where discovered in ROSAT spectra of quasars and confirmed by ASCA, BeppoSAX and Chandra. In most cases it was not possible to constrain adequately the redshift of the absorber from the X-ray data alone. Two possibilities remain open: a) absorption at the quasar redshift; and b) intervening absorption. The evidences in favour of intrinsic absorption are all indirect. Sensitive XMM observations can discriminate between these different scenarios. If the absorption is at the quasar redshift we can study whether the quasar environment evolves with the Cosmic time.

  1. The spatial resolution of epidemic peaks.

    PubMed

    Mills, Harriet L; Riley, Steven

    2014-04-01

    The emergence of novel respiratory pathogens can challenge the capacity of key health care resources, such as intensive care units, that are constrained to serve only specific geographical populations. An ability to predict the magnitude and timing of peak incidence at the scale of a single large population would help to accurately assess the value of interventions designed to reduce that peak. However, current disease-dynamic theory does not provide a clear understanding of the relationship between: epidemic trajectories at the scale of interest (e.g. city); population mobility; and higher resolution spatial effects (e.g. transmission within small neighbourhoods). Here, we used a spatially-explicit stochastic meta-population model of arbitrary spatial resolution to determine the effect of resolution on model-derived epidemic trajectories. We simulated an influenza-like pathogen spreading across theoretical and actual population densities and varied our assumptions about mobility using Latin-Hypercube sampling. Even though, by design, cumulative attack rates were the same for all resolutions and mobilities, peak incidences were different. Clear thresholds existed for all tested populations, such that models with resolutions lower than the threshold substantially overestimated population-wide peak incidence. The effect of resolution was most important in populations which were of lower density and lower mobility. With the expectation of accurate spatial incidence datasets in the near future, our objective was to provide a framework for how to use these data correctly in a spatial meta-population model. Our results suggest that there is a fundamental spatial resolution for any pathogen-population pair. If underlying interactions between pathogens and spatially heterogeneous populations are represented at this resolution or higher, accurate predictions of peak incidence for city-scale epidemics are feasible. PMID:24722420

  2. Tunable absorption in heterostructures composed of a highly absorptive metallic film and Fibonacci fractal photonic crystals

    NASA Astrophysics Data System (ADS)

    Qiao, Wei; Sun, Jie; Du, Gui-Qiang

    2016-03-01

    We have theoretically investigated the anomalous optical properties of heterostructures composed of a highly absorptive metal film and a truncated Fibonacci fractal photonic crystal. It is found that one or multiple highly reflected peaks, even enhanced transmission narrowband, can be realized in the near-complete absorption broadband, where the photonic crystals are selected with various Fibonacci sequences or a given sequence as the basic unit. These properties are significant to design important reflection or transmission optical devices in the visible and near-infrared ranges.

  3. INTERSTELLAR SILICATE DUST IN FIVE QUASAR ABSORPTION SYSTEMS

    SciTech Connect

    Kulkarni, Varsha P.; Torres-Garcia, Legna M.; Som, Debopam; York, Donald G.; Welty, Daniel E.; Vladilo, Giovanni

    2011-01-01

    We report on a study of interstellar silicate dust in five quasar absorption systems at 0.44 < z{sub abs} < 1.31 toward quasars Q0235+164, 3C196, Q0852+3435, Q0937+5628, and Q1203+0634, using data from the Infrared Spectrograph on board the Spitzer Space Telescope. In the absorbers toward Q0235+164, 3C196, Q0852+3435, and Q0937+5628, the 9.7 {mu}m silicate feature is detected in absorption at {approx}5{sigma}-10{sigma} significance, with rest-frame equivalent widths of {approx}0.2-0.5 {mu}m. For Q1203+0634, the noisy data allow us to make only a 3.6{sigma} detection of absorption at 10 {mu}m. Fits to the redshifted 9.7 {mu}m features with four possible template profiles indicate that the laboratory amorphous olivine profile generally provides the best fit, with inferred peak optical depths of {tau}{sub 9.7} {approx} 0.08-0.18. For three of the quasars with optical spectra available from the Sloan Digital Sky Survey, the Large Magellanic Cloud supershell extinction curve provides the best formal fits, with E(B - V) of 0.34-0.54 mag. A 2175 A extinction bump at the absorber redshift (known to exist in Q0235+164) appears to be present at >2.8{sigma} level in Q0852+3435, >2.5{sigma} level in Q1203+0634, and marginally at nearly 2{sigma} level in Q0937+5628. We briefly explore possible correlations between {tau}{sub 9.7} and the color excess, the strength of the 2175 A bump, and the metallicity (which appears to be relatively high for these absorbers, in the range of {approx}>0.1 solar to supersolar). While our measurements are consistent with a linear relation between {tau}{sub 9.7} and E(B - V), the {tau}{sub 9.7}/E(B - V) ratios for these quasar absorbers appear to be higher than those for diffuse interstellar clouds in the Milky Way, closer to values observed for the Galactic center. Some of these quasar sightlines may trace regions in the bulges of the galaxies responsible for the absorption systems.

  4. Structure of the dinuclear active site of urease. X-ray absorption spectroscopic study of native and 2-mercaptoethanol-inhibited bacterial and plant enzymes

    SciTech Connect

    Wang, Shengke; Scott, R.A. ); Lee, M.H.; Hausinger, R.P. ); Clark, P.A.; Wilcox, D.E. )

    1994-04-13

    The structures of the dinuclear Ni(II) active sites of urease from jack bean and Klebsiella aerogenes are compared with and without the addition of the inhibitor 2-mercaptoethanol (2-ME). No significant differences are observed by nickel K-edge X-ray absorption spectroscopy between the plant and bacterial enzymes. The Ni X-ray absorption edge spectra display an 8332-eV 1s[yields]3d peak intensity similar to that observed for five-coordinate Ni(II) compounds[sup 1] for both native and 2-ME-bound derivatives. Curve-fitting of Ni EXAFS data indicates that the average Ni(II) coordination environment in native urease can be described as Ni(imidazole)[sub x](N,O)[sub 5[minus]x], with x = 2 or 3. Addition of 2-ME results in replacement of one of the non-imidazole (N,O) ligands with (S,Cl) (most likely the thiolate sulfur of 2-ME) and results in the appearance of a new peak in the Fourier transforms that can only be fit with a Ni[center dot][center dot][center dot]Ni scattering component at a Ni-Ni distance of [approximately]3.26 [angstrom]. A structure for this 2-ME-bound dinuclear site is proposed to contain the two Ni(II) ions bridged by the thiolate sulfur of 2-ME.

  5. Skills Center.

    ERIC Educational Resources Information Center

    Canter, Patricia; And Others

    The services of the Living Skills Center for the Visually Handicapped, a habilitative service for blind young adults, are described. It is explained that the Center houses its participants in their own apartments in a large complex and has served over 70 young people in 4 years. The evaluation section describes such assessment instruments as an…

  6. Nonlinear intersubband optical absorption in a semiconductor quantum well

    NASA Technical Reports Server (NTRS)

    Ahn, D.; Chuang, S. L.

    1987-01-01

    The third-order nonlinear intersubband absorption in a semiconductor quantum well is studied theoretically using the density matrix formalism including intrasubband relaxation. It is shown that the peak absorption is reduced by half for an optical intensity 1 MW/sq cm for the well size L = 126.5 A with 3.0 x 10 to the 16th/cu cm electrons.

  7. No effect of food intake on clobazam absorption.

    PubMed Central

    Cenraud, B; Guyot, M; Levy, R H; Brachet-Liermain, A; Morselli, P L; Moreland, T A; Loiseau, P

    1983-01-01

    The kinetics of clobazam taken 3 h before, during, and 3 h after a standard hospital meal were studied in six healthy volunteers. Peak plasma levels were significantly lower when the drug was taken with or after meals suggesting that the rate of absorption was reduced by food. The mean area under the concentration vs time curve was not affected by the time of drug administration indicating that the meal had no effect upon the extent of absorption. PMID:6661360

  8. Compounds affecting cholesterol absorption

    NASA Technical Reports Server (NTRS)

    Hua, Duy H. (Inventor); Koo, Sung I. (Inventor); Noh, Sang K. (Inventor)

    2004-01-01

    A class of novel compounds is described for use in affecting lymphatic absorption of cholesterol. Compounds of particular interest are defined by Formula I: ##STR1## or a pharmaceutically acceptable salt thereof.

  9. Absorption heat pump system

    DOEpatents

    Grossman, Gershon

    1984-01-01

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  10. Absorption heat pump system

    DOEpatents

    Grossman, G.

    1982-06-16

    The efficiency of an absorption heat pump system is improved by conducting liquid from a second stage evaporator thereof to an auxiliary heat exchanger positioned downstream of a primary heat exchanger in the desorber of the system.

  11. Dipeptide absorption in man

    PubMed Central

    Hellier, M. D.; Holdsworth, C. D.; McColl, I.; Perrett, D.

    1972-01-01

    A quantitative perfusion method has been used to study intestinal absorption of two dipeptides—glycyl-glycine and glycyl-l-alanine—in normal subjects. In each case, the constituent amino acids were absorbed faster when presented as dipeptides than as free amino acids, suggesting intact dipeptide transport. During absorption constituent amino acids were measured within the lumen and it is suggested that these represent amino acids which have diffused back to the lumen after absorption as dipeptide. Portal blood analyses during absorption of a third dipeptide, glycyl-l-lysine, have shown that this dipeptide, known to be transported intact from the intestinal lumen, is hydrolysed to its constitutent amino acids before it reaches portal venous blood. PMID:4652039

  12. Predicting VO2peak from Submaximal- and Peak Exercise Models: The HUNT 3 Fitness Study, Norway

    PubMed Central

    Loe, Henrik; Nes, Bjarne M.; Wisløff, Ulrik

    2016-01-01

    Purpose Peak oxygen uptake (VO2peak) is seldom assessed in health care settings although being inversely linked to cardiovascular risk and all-cause mortality. The aim of this study was to develop VO2peak prediction models for men and women based on directly measured VO2peak from a large healthy population Methods VO2peak prediction models based on submaximal- and peak performance treadmill work were derived from multiple regression analysis. 4637 healthy men and women aged 20–90 years were included. Data splitting was used to generate validation and cross-validation samples. Results The accuracy for the peak performance models were 10.5% (SEE = 4.63 mL⋅kg-1⋅min-1) and 11.5% (SEE = 4.11 mL⋅kg-1⋅min-1) for men and women, respectively, with 75% and 72% of the variance explained. For the submaximal performance models accuracy were 14.1% (SEE = 6.24 mL⋅kg-1⋅min-1) and 14.4% (SEE = 5.17 mL⋅kg-1⋅min-1) for men and women, respectively, with 55% and 56% of the variance explained. The validation and cross-validation samples displayed SEE and variance explained in agreement with the total sample. Cross-classification between measured and predicted VO2peak accurately classified 91% of the participants within the correct or nearest quintile of measured VO2peak. Conclusion Judicious use of the exercise prediction models presented in this study offers valuable information in providing a fairly accurate assessment of VO2peak, which may be beneficial for risk stratification in health care settings. PMID:26794677

  13. Optical absorption measurement system

    DOEpatents

    Draggoo, Vaughn G.; Morton, Richard G.; Sawicki, Richard H.; Bissinger, Horst D.

    1989-01-01

    The system of the present invention contemplates a non-intrusive method for measuring the temperature rise of optical elements under high laser power optical loading to determine the absorption coefficient. The method comprises irradiating the optical element with a high average power laser beam, viewing the optical element with an infrared camera to determine the temperature across the optical element and calculating the absorption of the optical element from the temperature.

  14. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2004-08-31

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  15. Solar selective absorption coatings

    DOEpatents

    Mahoney, Alan R.; Reed, Scott T.; Ashley, Carol S.; Martinez, F. Edward

    2003-10-14

    A new class of solar selective absorption coatings are disclosed. These coatings comprise a structured metallic overlayer such that the overlayer has a sub-micron structure designed to efficiently absorb solar radiation, while retaining low thermal emissivity for infrared thermal radiation. A sol-gel layer protects the structured metallic overlayer from mechanical, thermal, and environmental degradation. Processes for producing such solar selective absorption coatings are also disclosed.

  16. Plasmonic nature of the terahertz conductivity peak in single-wall carbon nanotubes.

    PubMed

    Zhang, Qi; Hároz, Erik H; Jin, Zehua; Ren, Lei; Wang, Xuan; Arvidson, Rolf S; Lüttge, Andreas; Kono, Junichiro

    2013-01-01

    Plasmon resonance is expected to occur in metallic and doped semiconducting carbon nanotubes in the terahertz frequency range, but its convincing identification has so far been elusive. The origin of the terahertz conductivity peak commonly observed for carbon nanotube ensembles remains controversial. Here we present results of optical, terahertz, and direct current (DC) transport measurements on highly enriched metallic and semiconducting nanotube films. A broad and strong terahertz conductivity peak appears in both types of films, whose behaviors are consistent with the plasmon resonance explanation, firmly ruling out other alternative explanations such as absorption due to curvature-induced gaps. PMID:24224898

  17. Peak Oil, Food Systems, and Public Health

    PubMed Central

    Parker, Cindy L.; Kirschenmann, Frederick L.; Tinch, Jennifer; Lawrence, Robert S.

    2011-01-01

    Peak oil is the phenomenon whereby global oil supplies will peak, then decline, with extraction growing increasingly costly. Today's globalized industrial food system depends on oil for fueling farm machinery, producing pesticides, and transporting goods. Biofuels production links oil prices to food prices. We examined food system vulnerability to rising oil prices and the public health consequences. In the short term, high food prices harm food security and equity. Over time, high prices will force the entire food system to adapt. Strong preparation and advance investment may mitigate the extent of dislocation and hunger. Certain social and policy changes could smooth adaptation; public health has an essential role in promoting a proactive, smart, and equitable transition that increases resilience and enables adequate food for all. PMID:21778492

  18. 27 CFR 9.140 - Atlas Peak.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... miles to the highest point of an unnamed peak of 1268 feet elevation in section 12, T. 6 N., R. 4 W. on... 12 and 13, T. 7 N., R. 4 W. on the Yountville U.S.G.S. map; (10) Then following the section boundary... elevation, located in section 10, T. N., R. 4 W.; (12) Then northwest in a straight line approximately...

  19. 27 CFR 9.140 - Atlas Peak.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... miles to the highest point of an unnamed peak of 1268 feet elevation in section 12, T. 6 N., R. 4 W. on... 12 and 13, T. 7 N., R. 4 W. on the Yountville U.S.G.S. map; (10) Then following the section boundary... elevation, located in section 10, T. N., R. 4 W.; (12) Then northwest in a straight line approximately...

  20. Age does not alter acetaminophen absorption.

    PubMed

    Divoll, M; Ameer, B; Abernethy, D R; Greenblatt, D J

    1982-04-01

    Twenty-eight healthy volunteers (age range, 22-78 years) received 650 mg of acetaminophen (AAP) on three separate occasions. The modes of administration were 1) intravenous, 5-minute infusion; 2) oral, with two 325-mg tablets; and 3) oral, with 650 mg as an elixir preparation. Plasma levels of AAP were determined in blood samples drawn up to 12 hours after the dose. The mean (+/- sd) kinetic variables for absorption of AAP from tablets in young and elderly were peak plasma concentration, 11.8 (+/- 4.2) vs 10.9 (+/- 4.1) micrograms/ml; peak time, 0.79 (+/- .54) vs 0.69 (+/- .40) hours after the dose; absorption half-life, 12.6 (+/- 9.8) vs. 8.2 (+/- 5.3) minutes; and absolute systemic availability, 79 (+/- 9) vs 72 (+/- 11) per cent. For AAP elixir, the corresponding values were 12.6 (+/- 5.4) vs 13.7 (+/- 6.0) micrograms/ml; 0.52 (+/- .24) vs 0.54 (+/- .51) hours; 8.6 (+/- 6.2) vs 6.1 (+/- 6.6) minutes; and 87 (+/- 9) vs 80 (+/- 9) per cent. Absolute bioavailability of both oral dosage forms was significantly less then 100 per cent in all groups. Elderly subjects tended to show lower availability of both oral preparations, but the difference was of borderline significance (P less than .50). Age did not influence any other measures of absorption. Since the absorption rate of acetaminophen may be indicative of the gastric emptying rate, age does not appear to alter this rate-limiting step in drug absorption. PMID:7069091

  1. Effects of fictive temperature and halogen doping on the boson peak in silica glass

    NASA Astrophysics Data System (ADS)

    Shimodaira, N.; Saito, K.; Hiramitsu, N.; Matsushita, S.; Ikushima, A. J.

    2005-01-01

    We have investigated the effect of structural disorder on the boson peak in the Raman scattering of silica glass. The structural disorder was controlled in two ways: fictive temperature (Tf) and concentration of doped halogen element (F or Cl). As results, it has been simply demonstrated from nonreduced Raman spectra that (1) the peak position and full width at half maximum of the boson peak linearly increase with increasing Tf irrespective of the halogen concentrations, and in contrast, (2) the intensity is rather strongly dependent on the halogen concentrations than Tf . Since the result in (1) is much similar to the dependence on Tf and fluorine concentration for the IR absorption around 2260cm-1 , it has been concluded that the boson peak in silica glass is microscopically related to the average magnitude and distribution of Si-O-Si bond angles in glass network. The intensity enhancement in (2) has suggested two possibilities about the contribution of the doped halogen element to the boson peak: One is a direct contribution of F or Cl atoms due to diffusive motions falling within the range of the boson peak. The other is an indirect contribution introduced by the termination of Si-O-Si bridges to some sort of vibrational motions, which may be related to the boson peak.

  2. Revisiting Twomey's approximation for peak supersaturation

    NASA Astrophysics Data System (ADS)

    Shipway, B. J.

    2015-04-01

    Twomey's seminal 1959 paper provided lower and upper bound approximations to the estimation of peak supersaturation within an updraft and thus provides the first closed expression for the number of nucleated cloud droplets. The form of this approximation is simple, but provides a surprisingly good estimate and has subsequently been employed in more sophisticated treatments of nucleation parametrization. In the current paper, we revisit the lower bound approximation of Twomey and make a small adjustment that can be used to obtain a more accurate calculation of peak supersaturation under all potential aerosol loadings and thermodynamic conditions. In order to make full use of this improved approximation, the underlying integro-differential equation for supersaturation evolution and the condition for calculating peak supersaturation are examined. A simple rearrangement of the algebra allows for an expression to be written down that can then be solved with a single lookup table with only one independent variable for an underlying lognormal aerosol population. While multimodal aerosol with N different dispersion characteristics requires 2N+1 inputs to calculate the activation fraction, only N of these one-dimensional lookup tables are needed. No additional information is required in the lookup table to deal with additional chemical, physical or thermodynamic properties. The resulting implementation provides a relatively simple, yet computationally cheap, physically based parametrization of droplet nucleation for use in climate and Numerical Weather Prediction models.

  3. [Fast spectral modeling based on Voigt peaks].

    PubMed

    Li, Jin-rong; Dai, Lian-kui

    2012-03-01

    Indirect hard modeling (IHM) is a recently introduced method for quantitative spectral analysis, which was applied to the analysis of nonlinear relation between mixture spectrum and component concentration. In addition, IHM is an effectual technology for the analysis of components of mixture with molecular interactions and strongly overlapping bands. Before the establishment of regression model, IHM needs to model the measured spectrum as a sum of Voigt peaks. The precision of the spectral model has immediate impact on the accuracy of the regression model. A spectrum often includes dozens or even hundreds of Voigt peaks, which mean that spectral modeling is a optimization problem with high dimensionality in fact. So, large operation overhead is needed and the solution would not be numerically unique due to the ill-condition of the optimization problem. An improved spectral modeling method is presented in the present paper, which reduces the dimensionality of optimization problem by determining the overlapped peaks in spectrum. Experimental results show that the spectral modeling based on the new method is more accurate and needs much shorter running time than conventional method. PMID:22582612

  4. METing SUSY on the Z peak

    NASA Astrophysics Data System (ADS)

    Barenboim, G.; Bernabeu, J.; Mitsou, V. A.; Romero, E.; Vives, O.

    2016-02-01

    Recently the ATLAS experiment announced a 3 σ excess at the Z-peak consisting of 29 pairs of leptons together with two or more jets, ET^{miss} > 225 GeV and HT > 600 GeV, to be compared with 10.6 ± 3.2 expected lepton pairs in the Standard Model. No excess outside the Z-peak was observed. By trying to explain this signal with SUSY we find that only relatively light gluinos, m_{tilde{g}} ≲ 1.2 TeV, together with a heavy neutralino NLSP of m_{tilde{χ }} ≳ 400 GeV decaying predominantly to Z-boson plus a light gravitino, such that nearly every gluino produces at least one Z-boson in its decay chain, could reproduce the excess. We construct an explicit general gauge mediation model able to reproduce the observed signal overcoming all the experimental limits. Needless to say, more sophisticated models could also reproduce the signal, however, any model would have to exhibit the following features: light gluinos, or heavy particles with a strong production cross section, producing at least one Z-boson in its decay chain. The implications of our findings for the Run II at LHC with the scaling on the Z peak, as well as for the direct search of gluinos and other SUSY particles, are pointed out.

  5. Eyesight and the solar Wien peak

    NASA Astrophysics Data System (ADS)

    Overduin, James M.

    2003-03-01

    It is sometimes said that humans see best at yellow-green wavelengths because they have evolved under a Sun whose blackbody spectrum has a Wien peak in the green part of the spectrum. However, as a function of frequency, the solar blackbody spectrum peaks in the infrared. Why did human vision not evolve toward a peak sensitivity in this range, if the eye is an efficient quantum detector of photons? The puzzle is resolved if we assume that natural selection acted in such a way as to maximize the amount of energy that can be detected by the retina across a range of wavelengths (whose upper and lower limits are fixed by biological constraints). It is then found that our eyes are indeed perfectly adapted to life under a class G2 star. Extending this reasoning allows educated guesses to be made about the kind of eyesight that might have evolved in extrasolar planetary systems such as that of the red dwarf Gliese 876.

  6. Temperature dependent absorption cross-sections of O2-O2 collision pairs between 340 and 630 nm and at atmospherically relevant pressure.

    PubMed

    Thalman, Ryan; Volkamer, Rainer

    2013-10-01

    The collisions between two oxygen molecules give rise to O4 absorption in the Earth atmosphere. O4 absorption is relevant to atmospheric transmission and Earth's radiation budget. O4 is further used as a reference gas in Differential Optical Absorption Spectroscopy (DOAS) applications to infer properties of clouds and aerosols. The O4 absorption cross section spectrum of bands centered at 343, 360, 380, 446, 477, 532, 577 and 630 nm is investigated in dry air and oxygen as a function of temperature (203-295 K), and at 820 mbar pressure. We characterize the temperature dependent O4 line shape and provide high precision O4 absorption cross section reference spectra that are suitable for atmospheric O4 measurements. The peak absorption cross-section is found to increase at lower temperatures due to a corresponding narrowing of the spectral band width, while the integrated cross-section remains constant (within <3%, the uncertainty of our measurements). The enthalpy of formation is determined to be ΔH(250) = -0.12 ± 0.12 kJ mol(-1), which is essentially zero, and supports previous assignments of O4 as collision induced absorption (CIA). At 203 K, van der Waals complexes (O(2-dimer)) contribute less than 0.14% to the O4 absorption in air. We conclude that O(2-dimer) is not observable in the Earth atmosphere, and as a consequence the atmospheric O4 distribution is for all practical means and purposes independent of temperature, and can be predicted with an accuracy of better than 10(-3) from knowledge of the oxygen concentration profile. PMID:23928555

  7. Light, Alpha, and Fe-peak Element Abundances in the Galactic Bulge

    NASA Astrophysics Data System (ADS)

    Johnson, Christian I.; Rich, R. Michael; Kobayashi, Chiaki; Kunder, Andrea; Koch, Andreas

    2014-10-01

    We present radial velocities and chemical abundances of O, Na, Mg, Al, Si, Ca, Cr, Fe, Co, Ni, and Cu for a sample of 156 red giant branch stars in two Galactic bulge fields centered near (l, b) = (+5.25,-3.02) and (0,-12). The (+5.25,-3.02) field also includes observations of the bulge globular cluster NGC 6553. The results are based on high-resolution (R ~ 20,000), high signal-to-noise ration (S/N >~ 70) FLAMES-GIRAFFE spectra obtained through the European Southern Observatory archive. However, we only selected a subset of the original observations that included spectra with both high S/N and that did not show strong TiO absorption bands. This work extends previous analyses of this data set beyond Fe and the α-elements Mg, Si, Ca, and Ti. While we find reasonable agreement with past work, the data presented here indicate that the bulge may exhibit a different chemical composition than the local thick disk, especially at [Fe/H] >~ -0.5. In particular, the bulge [α/Fe] ratios may remain enhanced to a slightly higher [Fe/H] than the thick disk, and the Fe-peak elements Co, Ni, and Cu appear enhanced compared to the disk. There is also some evidence that the [Na/Fe] (but not [Al/Fe]) trends between the bulge and local disk may be different at low and high metallicity. We also find that the velocity dispersion decreases as a function of increasing [Fe/H] for both fields, and do not detect any significant cold, high-velocity populations. A comparison with chemical enrichment models indicates that a significant fraction of hypernovae may be required to explain the bulge abundance trends, and that initial mass functions that are steep, top-heavy (and do not include strong outflow), or truncated to avoid including contributions from stars >40 M ⊙ are ruled out, in particular because of disagreement with the Fe-peak abundance data. For most elements, the NGC 6553 stars exhibit abundance trends nearly identical to comparable metallicity bulge field stars. However, the

  8. Light, alpha, and Fe-peak element abundances in the galactic bulge

    SciTech Connect

    Johnson, Christian I.; Rich, R. Michael; Kobayashi, Chiaki; Kunder, Andrea; Koch, Andreas E-mail: rmr@astro.ucla.edu E-mail: akunder@aip.de

    2014-10-01

    We present radial velocities and chemical abundances of O, Na, Mg, Al, Si, Ca, Cr, Fe, Co, Ni, and Cu for a sample of 156 red giant branch stars in two Galactic bulge fields centered near (l, b) = (+5.25,–3.02) and (0,–12). The (+5.25,–3.02) field also includes observations of the bulge globular cluster NGC 6553. The results are based on high-resolution (R ∼ 20,000), high signal-to-noise ration (S/N ≳ 70) FLAMES-GIRAFFE spectra obtained through the European Southern Observatory archive. However, we only selected a subset of the original observations that included spectra with both high S/N and that did not show strong TiO absorption bands. This work extends previous analyses of this data set beyond Fe and the α-elements Mg, Si, Ca, and Ti. While we find reasonable agreement with past work, the data presented here indicate that the bulge may exhibit a different chemical composition than the local thick disk, especially at [Fe/H] ≳ –0.5. In particular, the bulge [α/Fe] ratios may remain enhanced to a slightly higher [Fe/H] than the thick disk, and the Fe-peak elements Co, Ni, and Cu appear enhanced compared to the disk. There is also some evidence that the [Na/Fe] (but not [Al/Fe]) trends between the bulge and local disk may be different at low and high metallicity. We also find that the velocity dispersion decreases as a function of increasing [Fe/H] for both fields, and do not detect any significant cold, high-velocity populations. A comparison with chemical enrichment models indicates that a significant fraction of hypernovae may be required to explain the bulge abundance trends, and that initial mass functions that are steep, top-heavy (and do not include strong outflow), or truncated to avoid including contributions from stars >40 M {sub ☉} are ruled out, in particular because of disagreement with the Fe-peak abundance data. For most elements, the NGC 6553 stars exhibit abundance trends nearly identical to comparable metallicity bulge field

  9. Automated Critical Peak Pricing Field Tests: Program Descriptionand Results

    SciTech Connect

    Piette, Mary Ann; Watson, David; Motegi, Naoya; Kiliccote, Sila; Xu, Peng

    2006-04-06

    California utilities have been exploring the use of critical peak prices (CPP) to help reduce needle peaks in customer end-use loads. CPP is a form of price-responsive demand response (DR). Recent experience has shown that customers have limited knowledge of how to operate their facilities in order to reduce their electricity costs under CPP (Quantum 2004). While the lack of knowledge about how to develop and implement DR control strategies is a barrier to participation in DR programs like CPP, another barrier is the lack of automation of DR systems. During 2003 and 2004, the PIER Demand Response Research Center (DRRC) conducted a series of tests of fully automated electric demand response (Auto-DR) at 18 facilities. Overall, the average of the site-specific average coincident demand reductions was 8% from a variety of building types and facilities. Many electricity customers have suggested that automation will help them institutionalize their electric demand savings and improve their overall response and DR repeatability. This report focuses on and discusses the specific results of the Automated Critical Peak Pricing (Auto-CPP, a specific type of Auto-DR) tests that took place during 2005, which build on the automated demand response (Auto-DR) research conducted through PIER and the DRRC in 2003 and 2004. The long-term goal of this project is to understand the technical opportunities of automating demand response and to remove technical and market impediments to large-scale implementation of automated demand response (Auto-DR) in buildings and industry. A second goal of this research is to understand and identify best practices for DR strategies and opportunities. The specific objectives of the Automated Critical Peak Pricing test were as follows: (1) Demonstrate how an automated notification system for critical peak pricing can be used in large commercial facilities for demand response (DR). (2) Evaluate effectiveness of such a system. (3) Determine how customers

  10. Quantifying peak discharges for historical floods

    USGS Publications Warehouse

    Cook, J.L.

    1987-01-01

    It is usually advantageous to use information regarding historical floods, if available, to define the flood-frequency relation for a stream. Peak stages can sometimes be determined for outstanding floods that occurred many years ago before systematic gaging of streams began. In the United States, this information is usually not available for more than 100-200 years, but in countries with long cultural histories, such as China, historical flood data are available at some sites as far back as 2,000 years or more. It is important in flood studies to be able to assign a maximum discharge rate and an associated error range to the historical flood. This paper describes the significant characteristics and uncertainties of four commonly used methods for estimating the peak discharge of a flood. These methods are: (1) rating curve (stage-discharge relation) extension; (2) slope conveyance; (3) slope area; and (4) step backwater. Logarithmic extensions of rating curves are based on theoretical plotting techniques that results in straight line extensions provided that channel shape and roughness do not change significantly. The slope-conveyance and slope-area methods are based on the Manning equation, which requires specific data on channel size, shape and roughness, as well as the water-surface slope for one or more cross-sections in a relatively straight reach of channel. The slope-conveyance method is used primarily for shaping and extending rating curves, whereas the slope-area method is used for specific floods. The step-backwater method, also based on the Manning equation, requires more cross-section data than the slope-area ethod, but has a water-surface profile convergence characteristic that negates the need for known or estimated water-surface slope. Uncertainties in calculating peak discharge for historical floods may be quite large. Various investigations have shown that errors in calculating peak discharges by the slope-area method under ideal conditions for

  11. Will peak oil accelerate carbon dioxide emissions?

    NASA Astrophysics Data System (ADS)

    Caldeira, K.; Davis, S. J.; Cao, L.

    2008-12-01

    The relative scarcity of oil suggests that oil production is peaking and will decline thereafter. Some have suggested that this represents an opportunity to reduce carbon dioxide emissions. However, in the absence of constraints on carbon dioxide emission, "peak oil" may drive a shift towards increased reliance on coal as a primary energy source. Because coal per unit energy, in the absence of carbon capture and disposal, releases more carbon dioxide to the atmosphere than oil, "peak oil" may lead to an acceleration of carbon dioxide emissions. We will never run out of oil. As oil becomes increasingly scarce, prices will rise and therefore consumption will diminish. As prices rise, other primary energy sources will become increasingly competitive with oil. The developed world uses oil primarily as a source of transportation fuels. The developing world uses oil primarily for heat and power, but the trend is towards increasing reliance on oil for transportation. Liquid fuels, including petroleum derivatives such as gasoline and diesel fuel, are attractive as transportation fuels because of their relative abundance of energy per unit mass and volume. Such considerations are especially important for the air transport industry. Today, there is little that can compete with petroleum-derived transportation fuels. Future CO2 emissions from the transportation sector largely depend on what replaces oil as a source of fuel. Some have suggested that biomass-derived ethanol, hydrogen, or electricity could play this role. Each of these potential substitutes has its own drawbacks (e.g., low power density per unit area in the case of biomass, low power density per unit volume in the case of hydrogen, and low power density per unit mass in the case of battery storage). Thus, it is entirely likely that liquefaction of coal could become the primary means by which transportation fuels are produced. Since the burning of coal produces more CO2 per unit energy than does the burning of

  12. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, Robert C.; Biermann, Wendell J.

    1989-01-01

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit.

  13. Seven-effect absorption refrigeration

    DOEpatents

    DeVault, R.C.; Biermann, W.J.

    1989-05-09

    A seven-effect absorption refrigeration cycle is disclosed utilizing three absorption circuits. In addition, a heat exchanger is used for heating the generator of the low absorption circuit with heat rejected from the condenser and absorber of the medium absorption circuit. A heat exchanger is also provided for heating the generator of the medium absorption circuit with heat rejected from the condenser and absorber of the high absorption circuit. If desired, another heat exchanger can also be provided for heating the evaporator of the high absorption circuit with rejected heat from either the condenser or absorber of the low absorption circuit. 1 fig.

  14. A naked eye refractive index sensor with a visible multiple peak metamaterial absorber.

    PubMed

    Ma, Heli; Song, Kun; Zhou, Liang; Zhao, Xiaopeng

    2015-01-01

    We report a naked eye refractive index sensor with a visible metamaterial absorber. The visible metamaterial absorber consisting of a silver dendritic/dielectric/metal structure shows multiple absorption peaks. By incorporating a gain material (rhodamine B) into the dielectric layer, the maximal magnitude of the absorption peak can be improved by about 30%. As the metamaterial absorber is sensitive to the refractive index of glucose solutions, it can function as a sensor that quickly responds to variations of the refractive index of the liquid. Meanwhile, since the response is presented via color changes, it can be clearly observed by the naked eyes. Further experiments have confirmed that the sensor can be used repeatedly. PMID:25822141

  15. Mechanisms Underlying Carotenoid Absorption in Oxygenic Photosynthetic Proteins*

    PubMed Central

    Mendes-Pinto, Maria M.; Galzerano, Denise; Telfer, Alison; Pascal, Andrew A.; Robert, Bruno; Ilioaia, Cristian

    2013-01-01

    The electronic properties of carotenoid molecules underlie their multiple functions throughout biology, and tuning of these properties by their in vivo locus is of vital importance in a number of cases. This is exemplified by photosynthetic carotenoids, which perform both light-harvesting and photoprotective roles essential to the photosynthetic process. However, despite a large number of scientific studies performed in this field, the mechanism(s) used to modulate the electronic properties of carotenoids remain elusive. We have chosen two specific cases, the two β-carotene molecules in photosystem II reaction centers and the two luteins in the major photosystem II light-harvesting complex, to investigate how such a tuning of their electronic structure may occur. Indeed, in each case, identical molecular species in the same protein are seen to exhibit different electronic properties (most notably, shifted absorption peaks). We assess which molecular parameters are responsible for this in vivo tuning process and attempt to assign it to specific molecular events imposed by their binding pockets. PMID:23720734

  16. Mechanisms underlying carotenoid absorption in oxygenic photosynthetic proteins.

    PubMed

    Mendes-Pinto, Maria M; Galzerano, Denise; Telfer, Alison; Pascal, Andrew A; Robert, Bruno; Ilioaia, Cristian

    2013-06-28

    The electronic properties of carotenoid molecules underlie their multiple functions throughout biology, and tuning of these properties by their in vivo locus is of vital importance in a number of cases. This is exemplified by photosynthetic carotenoids, which perform both light-harvesting and photoprotective roles essential to the photosynthetic process. However, despite a large number of scientific studies performed in this field, the mechanism(s) used to modulate the electronic properties of carotenoids remain elusive. We have chosen two specific cases, the two β-carotene molecules in photosystem II reaction centers and the two luteins in the major photosystem II light-harvesting complex, to investigate how such a tuning of their electronic structure may occur. Indeed, in each case, identical molecular species in the same protein are seen to exhibit different electronic properties (most notably, shifted absorption peaks). We assess which molecular parameters are responsible for this in vivo tuning process and attempt to assign it to specific molecular events imposed by their binding pockets. PMID:23720734

  17. Micrometoric Impact Effects: Peak Pressure versus Spectral Variation

    NASA Technical Reports Server (NTRS)

    Jensen, Elizabeth; Lederer, S. M.; Wooden, D. H.; Lindsay, S. S.; Keller, L. P.; Cintala, M. J.; Zolensky, M. E.

    2013-01-01

    At the Experimental Impact Laboratory at NASA Johnson Space Center, we have investigated the surface properties of asteroids caused by collisions in the mid-infrared (2.5 to 16 microns) by impacting forsterite and enstatite across a range of velocities (as predicted by the Nice Model) and at varying temperatures. The crystal structure in these minerals can be deformed by the shock wave from the impact as well as sheared into smaller particle sizes. Our current focus is on the differing effects between 2.3 and 2.6 km/sec, as well as the differences between a cold sample at -20C and a room temperature sample at 25C. We find that the spectral variation and crystal deformation varies non-linearly with the peak shock pressure.

  18. Senior Centers

    MedlinePlus Videos and Cool Tools

    ... something many older adults would like to do as long as they can. Senior centers, adult day care, transportation, ... adults who live independently can go to find a variety of social and recreational activities. [Karen Albers] ...

  19. Electro-absorption of silicene and bilayer graphene quantum dots

    NASA Astrophysics Data System (ADS)

    Abdelsalam, Hazem; Talaat, Mohamed H.; Lukyanchuk, Igor; Portnoi, M. E.; Saroka, V. A.

    2016-07-01

    We study numerically the optical properties of low-buckled silicene and AB-stacked bilayer graphene quantum dots subjected to an external electric field, which is normal to their surface. Within the tight-binding model, the optical absorption is calculated for quantum dots, of triangular and hexagonal shapes, with zigzag and armchair edge terminations. We show that in triangular silicene clusters with zigzag edges a rich and widely tunable infrared absorption peak structure originates from transitions involving zero energy states. The edge of absorption in silicene quantum dots undergoes red shift in the external electric field for triangular clusters, whereas blue shift takes place for hexagonal ones. In small clusters of bilayer graphene with zigzag edges the edge of absorption undergoes blue/red shift for triangular/hexagonal geometry. In armchair clusters of silicene blue shift of the absorption edge takes place for both cluster shapes, while red shift is inherent for both shapes of the bilayer graphene quantum dots.

  20. Control of enhanced optical absorption in {mu}c-Si

    SciTech Connect

    Kalkan, A.K.; Fonash, S.J.

    1997-07-01

    The influence of grain size on the enhanced optical absorption of {micro}c-Si has been investigated using films of various grain sizes prepared by solid phase crystallization. The authors show that they can control this grain size and therefore the degree of absorption changes. For grain sizes below a threshold range significant absorption enhancement can be seen in the photon energy range of 1 to {approximately}3 eV and the absorption characteristics of these films show that the dominant mode of optical transitions is indirect. A correlation between first order Raman peak broadening and enhanced absorption was found suggesting both effects are related to confinement. A simple model was developed to see how confinement in the crystallites could influence indirect optical transitions.

  1. Current Status of the Synchrotron Radiation Center

    NASA Astrophysics Data System (ADS)

    Kinraide, R.; Moore, C. J.; Jacobs, K. D.; Severson, M.; Bissen, M. J.; Frazer, B.; Bisognano, J. J.; Bosch, R. A.; Eisert, D.; Fisher, M.; Green, M. A.; Gundelach, C. T.; Hansen, R. W. C.; Hochst, H.; Julian, R. L.; Keil, R.; Kleman, K.; Kubala, T.; Legg, R. A.; Pedley, B.; Rogers, G. C.; Stott, J. P.; Wallace, D. J.; Wehlitz, R.; Wiese, L. M.; Taylor, J.; Campuzano, J. C.; De Stasio, G.

    2004-05-01

    The Synchrotron Radiation Center (SRC) operates the Aladdin electron storage ring at energies of 800 MeV or 1 GeV in support of a broad range of national and international research programs. A low emittance configuration is in routine operation during 800-MeV shifts and offers improved photon flux density with about the same beam lifetime. An improved undulator compensation algorithm and new optical beam position monitors have been implemented improving beam stability and maintaining vertical beam size variations to < 2% peak-to-peak during undulator scanning. Instrumentation initiatives include construction of a modified Wadsworth beamline (7.8 - 50 eV) and a variable-line-spacing plane-grating monochromator (VLS-PGM, 75 - 2000 eV) to utilize radiation from a permanent magnet undulator. The Wadsworth beamline is being commissioned for photoelectron spectroscopy (PES) experiments using high-resolution Scienta analyzers. The VLS-PGM is being constructed for experiments that require higher photon energies and high flux density such as x-ray photoemission electron microscopy (X-PEEM) and x-ray absorption spectroscopy (XAS). It is scheduled to be available in early 2004. Recent research at the SRC has produced exciting results in a variety of fields, culminating in eight articles published in Physical Review Letters and three in Nature since October 2002, in addition to articles in many other publications. An outreach program offers research experiences for undergraduates and provides the general public with an awareness of synchrotron radiation. Hands-on workshops and activities on FTIR microscopy and X-PEEM are offered for graduate students and scientists. SRC sponsors a summer Research Experience for Undergraduates (REU) program and offers opportunities to non-research universities and high schools. Tours and educational events are coordinated with local civic groups and schools. Open houses are offered that include tours, demonstrations, and family activities.

  2. Petawatt laser absorption bounded

    NASA Astrophysics Data System (ADS)

    Levy, Matthew; Wilks, Scott; Tabak, Max; Libby, Stephen; Baring, Matthew

    2014-10-01

    The interaction of petawatt (1015 W) lasers with solid matter forms the basis for advanced scientific applications such as table-top relativistic particle accelerators, ultrafast charged particle imaging systems and fast ignition inertial confinement fusion. Key metrics for these applications relate to absorption, yet conditions in this regime are so nonlinear that it is often impossible to know the fraction of absorbed light f, and even the range of f is unknown. In this presentation, using a relativistic Rankine-Hugoniot-like analysis, we show how to derive the theoretical maximum and minimum of f. These boundaries constrain nonlinear absorption mechanisms across the petawatt regime, forbidding high absorption values at low laser power and low absorption values at high laser power. Close agreement is shown with several dozens of published experimental data points and simulation results, helping to confirm the theory. For applications needing to circumvent the absorption bounds, these results will accelerate a shift from solid targets, towards structured and multilayer targets, and lead the development of new materials.

  3. Measuring non-local Lagrangian peak bias

    NASA Astrophysics Data System (ADS)

    Biagetti, Matteo; Chan, Kwan Chuen; Desjacques, Vincent; Paranjape, Aseem

    2014-06-01

    We investigate non-local Lagrangian bias contributions involving gradients of the linear density field, for which we have predictions from the excursion set peak formalism. We begin by writing down a bias expansion which includes all the bias terms, including the non-local ones. Having checked that the model furnishes a reasonable fit to the halo mass function, we develop a one-point cross-correlation technique to measure bias factors associated with χ2-distributed quantities. We validate the method with numerical realizations of peaks of Gaussian random fields before we apply it to N-body simulations. We focus on the lowest (quadratic) order non-local contributions -2χ _{10}(k_1\\cdot k_2) and χ _{01}[3(k_1\\cdot k_2)^2-k_1^2 k_2^2], where k_1, k_2 are wave modes. We can reproduce our measurement of χ10 if we allow for an offset between the Lagrangian halo centre-of-mass and the peak position. The sign and magnitude of χ10 is consistent with Lagrangian haloes sitting near linear density maxima. The resulting contribution to the halo bias can safely be ignored for M = 1013 M⊙ h-1, but could become relevant at larger halo masses. For the second non-local bias χ01 however, we measure a much larger magnitude than predicted by our model. We speculate that some of this discrepancy might originate from non-local Lagrangian contributions induced by non-spherical collapse.

  4. Calculating weighted estimates of peak streamflow statistics

    USGS Publications Warehouse

    Cohn, Timothy A.; Berenbrock, Charles; Kiang, Julie E.; Mason, Jr., Robert R.

    2012-01-01

    According to the Federal guidelines for flood-frequency estimation, the uncertainty of peak streamflow statistics, such as the 1-percent annual exceedance probability (AEP) flow at a streamgage, can be reduced by combining the at-site estimate with the regional regression estimate to obtain a weighted estimate of the flow statistic. The procedure assumes the estimates are independent, which is reasonable in most practical situations. The purpose of this publication is to describe and make available a method for calculating a weighted estimate from the uncertainty or variance of the two independent estimates.

  5. PeakVizor: Visual Analytics of Peaks in Video Clickstreams from Massive Open Online Courses.

    PubMed

    Chen, Qing; Chen, Yuanzhe; Liu, Dongyu; Shi, Conglei; Wu, Yingcai; Qu, Huamin

    2016-10-01

    Massive open online courses (MOOCs) aim to facilitate open-access and massive-participation education. These courses have attracted millions of learners recently. At present, most MOOC platforms record the web log data of learner interactions with course videos. Such large amounts of multivariate data pose a new challenge in terms of analyzing online learning behaviors. Previous studies have mainly focused on the aggregate behaviors of learners from a summative view; however, few attempts have been made to conduct a detailed analysis of such behaviors. To determine complex learning patterns in MOOC video interactions, this paper introduces a comprehensive visualization system called PeakVizor. This system enables course instructors and education experts to analyze the "peaks" or the video segments that generate numerous clickstreams. The system features three views at different levels: the overview with glyphs to display valuable statistics regarding the peaks detected; the flow view to present spatio-temporal information regarding the peaks; and the correlation view to show the correlation between different learner groups and the peaks. Case studies and interviews conducted with domain experts have demonstrated the usefulness and effectiveness of PeakVizor, and new findings about learning behaviors in MOOC platforms have been reported. PMID:26661473

  6. The measurement of absolute absorption of millimeter radiation in gases - The absorption of CO and O2

    NASA Technical Reports Server (NTRS)

    Read, William G.; Cohen, Edward A.; Pickett, Herbert M.; Hillig, Kurt W., II

    1988-01-01

    An apparatus is described that will measure absolute absorption of millimeter radiation in gases. The method measures the change in the quality factor of a Fabry-Perot resonator with and without gas present. The magnitude of the change is interpreted in terms of the absorption of the lossy medium inside the resonator. Experiments have been performed on the 115-GHz CO line and the 119-GHz O2 line at two different temperatures to determine the linewidth parameter and the peak absorption value. These numbers can be combined to give the integrated intensity which can be accurately calculated from results of spectroscopy measurements. The CO results are within 2 percent percent of theoretically predicted valves. Measurements on O2 have shown that absorption can be measured as accurately as 0.5 dB/km with this technique. Results have been obtained for oxygen absolute absorption in the 60-80-GHz region.

  7. Studies of Element-Specific Local Structures in Compound Materials Using X-Ray Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Soo, Yun-Liang

    1995-01-01

    The x-ray absorption spectroscopy techniques have been used to study a variety of semiconductor and superconductor materials. In such experiments, synchrotron radiation harnessed by a delicate beamline electronic and control system are used to obtain data with analyzable quality in a reasonable time scale. The element-selectivity is achieved by selecting an energy-scan range close to a characteristic "absorption edge" of the selected element. Peak structures below the absorption edge (pre-edge structures) reflect the local unoccupied states of the selected atomic species. The position of absorption edge (part of the near-edge x-ray absorption fine structure, NEXAFS) provides some qualitative information of the effective valency of the selected element. And, most importantly, the modulation in the spectrum some 40 eV above the absorption edge (extended x-ray absorption fine structure, EXAFS) gives quantitative information of the local structure around the selected atomic species. The selected atomic species such as magnetic Mn ions in III-V diluted magnetic semiconductors (DMS) rm In_{1-x}Mn_{x}As, Mn as the luminescent centers in nanocrystals of ZnS, O in the CuO_2 planes which host the carriers in high-T_{rm c} superconductors, and F as the electron reservoir in the n-type high-T_{rm c} superconductors rm Nd_2CuO _{4-x}F_{x} all play an important role in the novel mechanism of these new materials. Along with other detailed information, our EXAFS results have revealed (i) III-V DMS can indeed be prepared by substitutional doping of magnetic impurities under proper processing conditions. (ii) Mn ions substitute for the Zn sites in the nanocrystals of ZnS with significant size-dependent local structural changes. (iii) Only ~6% of O in the CuO_2 planes in rm Nd_2CuO_{4 -x}F_{x} are substituted by F. The rest of F atoms substitute for O atoms in the NdO layers and serve as electron reservoirs. The NEXAFS results have shown that the effective valency of Mn in Zn

  8. Documented and potential extreme peak discharges and relation between potential extreme peak discharges and probable maximum flood peak discharges in Texas

    USGS Publications Warehouse

    Asquith, W.H.; Slade, R.M., Jr.

    1995-01-01

    The U.S. Geological Survey, in cooperation with the Texas Department of Transportation, conducted a study of extreme flood potential for Texas. Potential extreme peak discharges, derived from the relation between documented extreme peak discharges and their contributing drainage areas, can provide valuable information concerning the maximum expected peak discharge that could occur at a stream site. Documented extreme peak discharges and associated data were aggregated for 832 sites with and without streamflow-gaging stations in natural basins in Texas. A potential extreme peak discharge curve was developed for each of 11 hydrologic regions in Texas and for the State as a whole, based on documented extreme peak discharges and associated contributing drainage areas. The curve envelops, for a large range of drainage areas, the largest documented extreme peak discharges. Potential extreme peak discharges estimated from the curves were compared to probable maximum flood peak discharges estimated from various simulation models.

  9. Percutaneous absorption from soil.

    PubMed

    Andersen, Rosa Marie; Coman, Garrett; Blickenstaff, Nicholas R; Maibach, Howard I

    2014-01-01

    Abstract Some natural sites, as a result of contaminants emitted into the air and subsequently deposited in soil or accidental industrial release, have high levels of organic and non-organic chemicals in soil. In occupational and recreation settings, these could be potential sources of percutaneous exposure to humans. When investigating percutaneous absorption from soil - in vitro or vivo - soil load, particle size, layering, soil "age" time, along with the methods of performing the experiment and analyzing the results must be taken into consideration. Skin absorption from soil is generally reduced compared with uptake from water/acetone. However, the absorption of some compounds, e.g., pentachlorophenol, chlorodane and PCB 1254, are similar. Lipophilic compounds like dichlorodiphenyltrichloroethane, benzo[A]pyrene, and metals have the tendency to form reservoirs in skin. Thus, one should take caution in interpreting results directly from in vitro studies for risk assessment; in vivo validations are often required for the most relevant risk assessment. PMID:25205703

  10. Outreach Plans for Storm Peak Laboratory

    NASA Astrophysics Data System (ADS)

    Hallar, A. G.; McCubbin, I. B.

    2006-12-01

    The Desert Research Institute (DRI) operates a high elevation facility, Storm Peak Laboratory (SPL), located on the west summit of Mt. Werner in the Park Range near Steamboat Springs, Colorado at an elevation 10,500 ft. SPL provides an ideal location for long-term research on the interactions of atmospheric aerosol and gas- phase chemistry with cloud and natural radiation environments. SPL includes an office-type laboratory room for computer and instrumentation setup with outside air ports and cable access to the roof deck, a full kitchen and two bunk rooms with sleeping space for nine persons. We plan to create a unique summer undergraduate education experiences for students of diversity at Storm Peak Laboratory. As stressed by the College Pathways to Science Education Standards [Siebert and McIntosh, 2001], to support changes in K-12 science education transformations must first be made at the college level, including inquiry-oriented opportunities to engage in meaningful research. These workshops will be designed to allow students to experience the excitement of science, increasing their likelihood of pursing careers within the fields of scientific education or research.

  11. Low peak-power laser ultrasonics

    NASA Astrophysics Data System (ADS)

    Pierce, S. G.; Cleary, A.; Veres, I. A.; Culshaw, B.; Thursby, G.; McKee, C.; Swift, C.; Armstrong, I.

    2011-09-01

    Techniques for the successful excitation of guided ultrasonic waves using a low peak-power laser ultrasonic source are discussed and compared with more conventional Q-switched laser sources. The paper considers acoustic propagation in thin plates, in which the frequencies used, typically only the fundamental guided wave modes, are considered. Aspects of excitation and detection geometry are considered along with the physical mechanisms of photo-acoustic generation and the practical issues surrounding available source wavelengths and power outputs. Understanding of the effects of these constraints is critical for the successful application of the technique. Continuous wave excitation and fully arbitrary modulation schemes are compared, and a technique to control the bandwidth of Golay code modulation is introduced. It is shown that earlier work by the authors was capable of guided wave detection at peak-power densities of 104 W cm- 2. Later work has focussed on the use of erbium-doped fibre amplifiers combined with Golay code modulation to improve the recovered signal-to-noise ratio. Two key applications of the techniques are considered: material properties measurements (using inversion of dispersion curve data) and acoustic emission system calibration.

  12. Multiplasmon Absorption in Graphene

    NASA Astrophysics Data System (ADS)

    Jablan, Marinko; Chang, Darrick E.

    2015-06-01

    We show that graphene possesses a strong nonlinear optical response in the form of multiplasmon absorption, with exciting implications in classical and quantum nonlinear optics. Specifically, we predict that graphene nanoribbons can be used as saturable absorbers with low saturation intensity in the far-infrared and terahertz spectrum. Moreover, we predict that two-plasmon absorption and extreme localization of plasmon fields in graphene nanodisks can lead to a plasmon blockade effect, in which a single quantized plasmon strongly suppresses the possibility of exciting a second plasmon.

  13. Chaotic Systems with Absorption

    NASA Astrophysics Data System (ADS)

    Altmann, Eduardo G.; Portela, Jefferson S. E.; Tél, Tamás

    2013-10-01

    Motivated by applications in optics and acoustics we develop a dynamical-system approach to describe absorption in chaotic systems. We introduce an operator formalism from which we obtain (i) a general formula for the escape rate κ in terms of the natural conditionally invariant measure of the system, (ii) an increased multifractality when compared to the spectrum of dimensions Dq obtained without taking absorption and return times into account, and (iii) a generalization of the Kantz-Grassberger formula that expresses D1 in terms of κ, the positive Lyapunov exponent, the average return time, and a new quantity, the reflection rate. Simulations in the cardioid billiard confirm these results.

  14. Absorption heat pump system

    DOEpatents

    Grossman, Gershon; Perez-Blanco, Horacio

    1984-01-01

    An improvement in an absorption heat pump cycle is obtained by adding adiabatic absorption and desorption steps to the absorber and desorber of the system. The adiabatic processes make it possible to obtain the highest temperature in the absorber before any heat is removed from it and the lowest temperature in the desorber before heat is added to it, allowing for efficient utilization of the thermodynamic availability of the heat supply stream. The improved system can operate with a larger difference between high and low working fluid concentrations, less circulation losses, and more efficient heat exchange than a conventional system.

  15. Simulations of the Two-Dimensional Electronic Spectroscopy of the Photosystem II Reaction Center

    PubMed Central

    Lewis, K. L. M.; Fuller, F. D.; Myers, J. A.; Yocum, C. F.; Mukamel, S.; Abramavicius, D.; Ogilvie, J. P.

    2013-01-01

    We report simulations of the two-dimensional electronic spectroscopy of the Qy band of the D1-D2-Cyt b559 photosystem II reaction center at 77 K. We base the simulations on an existing Hamiltonian that was derived by simultaneous fitting to a wide range of linear spectroscopic measurements and described within modified Redfield theory. The model obtains reasonable agreement with most aspects of the two-dimensional spectra, including the overall peak shapes and excited state absorption features. It does not reproduce the rapid equilibration from high energy to low energy excitonic states evident by a strong cross-peak below the diagonal. We explore modifications to the model to incorporate new structural data and improve agreement with the two-dimensional spectra. We find that strengthening the system–bath coupling and lowering the degree of disorder significantly improves agreement with the cross-peak feature, while lessening agreement with the relative diagonal/antidiagonal width of the 2D spectra. We conclude that two-dimensional electronic spectroscopy provides a sensitive test of excitonic models of the photosystem II reaction center and discuss avenues for further refinement of such models. PMID:23210463

  16. Inhibition of digoxin absorption by neomycin.

    PubMed

    Lindenbaum, J; Maulitz, R M; Butler, V P

    1976-09-01

    The effect of the administration of the antibiotic neomycin sulfate on the absorption of digoxin was assessed in crossover studies in normal human volunteers. Doses of neomycin (1 and 3 g) markedly depressed serum digoxin concentrations, the areas under the serum concentration-time curves, and cumulative 6-day urinary digoxin excretion after the oral ingestion of 0.5 mg of the cardiac glycoside in tablet form. Neomycin also prolonged the mean time at which peak serum digoxin levels were attained by 1.7 to 3 hr. The inhibition of digoxin absorption was also seen: (1) when the antibiotic was given 3 or 6 hr before the cardiac glycoside, (2) with digoxin tablets of varying dissolution rate, (3) when digoxin or neomycin solutions were used instead of tablets, and (4) in a patient who had had a total gastrectomy. When neomycin was administered with maintenance doses of digoxin, steady state serum digoxin concentrations were significantly reduced. When neomycin was given after a 9-day period of digitalization, the terminal serum digoxin half-life was not significantly shortened. Single doses of neomycin did not interfere with the extent of absorption of d-xylose. In vitro, neomycin did not affect the movement of digoxin across dialysis membranes, nor did it precipitate digoxin out of human bile or intestinal fluid. Neomycin thus clearly depresses the rate and extent of digoxin absorption in man. The mechanism of this effect remains to be established. PMID:950089

  17. Direction dependence of the magneto-optical absorption in nanowires with Rashba interaction

    NASA Astrophysics Data System (ADS)

    Sakr, M. R.

    2016-09-01

    We study the directional dependence of the absorption spectrum of ballistic nanowires in the presence of gate-controlled Rashba spin-orbit interaction and an in-plane magnetic field. In the weak Rashba regime, our analytical and numerical results show that the absorption peaks associated with the first and third intersubband transitions exhibit frequency shifts and strong amplitude modulations as the direction of the magnetic field changes. If the field is parallel to the nanowire axis, these peaks disappear and the resonance frequencies of the whole absorption spectrum are given merely in terms of the Zeeman splitting and the energy scale characterizing the confinement potential. The second transition has an absorption peak that suffers an opposite frequency shift with amplitude that is largely direction independent. The amplitude modulation and frequency shift of the absorption spectrum is periodic in the angle that the magnetic field makes with the nanowire axis.

  18. Growth of Au nanoparticle films and the effect of nanoparticle shape on plasmon peak wavelength

    SciTech Connect

    Horikoshi, S. Matsumoto, N.; Kato, T.; Omata, Y.

    2014-05-21

    Metal nanoparticles (NPs) exhibit localized surface plasmon resonance (LSPR) and thus have potential for use in a wide range of applications. A facile technique for the preparation of NP films using an electron-cyclotron-resonance plasma sputtering method without a dewetting process is described. Field emission scanning electron microscopy (FE-SEM) observations revealed that the Au NPs grew independently as island-like particles during the first stage of sputtering and then coalesced with one another as sputtering time increased to ultimately form a continuous film. A plasmon absorption peak was observed via optical measurement of absorption efficiency. The LSPR peak shifted toward longer wavelengths (red shift) with an increase in sputtering time. The cause of this plasmon peak shift was theoretically investigated using the finite-difference time-domain calculation method. A realistic statistical distribution of the particle shapes based on FE-SEM observations was applied for the analysis, which has not been previously reported. It was determined that the change in the shape of the NPs from spheroidal to oval or slender due to coalescence with neighbouring NPs caused the LSPR peak shift. These results may enable the design of LSPR devices by controlling the characteristics of the nanoparticles, such as their size, shape, number density, and coverage.

  19. Achieving high energy absorption capacity in cellular bulk metallic glasses

    PubMed Central

    Chen, S. H.; Chan, K. C.; Wu, F. F.; Xia, L.

    2015-01-01

    Cellular bulk metallic glasses (BMGs) have exhibited excellent energy-absorption performance by inheriting superior strength from the parent BMGs. However, how to achieve high energy absorption capacity in cellular BMGs is vital but mysterious. In this work, using step-by-step observations of the deformation evolution of a series of cellular BMGs, the underlying mechanisms for the remarkable energy absorption capacity have been investigated by studying two influencing key factors: the peak stress and the decay of the peak stress during the plastic-flow plateau stages. An analytical model of the peak stress has been proposed, and the predicted results agree well with the experimental data. The decay of the peak stress has been attributed to the geometry change of the macroscopic cells, the formation of shear bands in the middle of the struts, and the “work-softening” nature of BMGs. The influencing factors such as the effect of the strut thickness and the number of unit cells have also been investigated and discussed. Strategies for achieving higher energy absorption capacity in cellular BMGs have been proposed. PMID:25973781

  20. Achieving high energy absorption capacity in cellular bulk metallic glasses

    NASA Astrophysics Data System (ADS)

    Chen, S. H.; Chan, K. C.; Wu, F. F.; Xia, L.

    2015-05-01

    Cellular bulk metallic glasses (BMGs) have exhibited excellent energy-absorption performance by inheriting superior strength from the parent BMGs. However, how to achieve high energy absorption capacity in cellular BMGs is vital but mysterious. In this work, using step-by-step observations of the deformation evolution of a series of cellular BMGs, the underlying mechanisms for the remarkable energy absorption capacity have been investigated by studying two influencing key factors: the peak stress and the decay of the peak stress during the plastic-flow plateau stages. An analytical model of the peak stress has been proposed, and the predicted results agree well with the experimental data. The decay of the peak stress has been attributed to the geometry change of the macroscopic cells, the formation of shear bands in the middle of the struts, and the “work-softening” nature of BMGs. The influencing factors such as the effect of the strut thickness and the number of unit cells have also been investigated and discussed. Strategies for achieving higher energy absorption capacity in cellular BMGs have been proposed.

  1. Statistical Short-Range Guidance for Peak Wind Speed Forecasts at Edwards Air Force Base, CA

    NASA Technical Reports Server (NTRS)

    Dreher, Joseph; Crawford, Winifred; Lafosse, Richard; Hoeth, Brian; Burns, Kerry

    2008-01-01

    The peak winds near the surface are an important forecast element for Space Shuttle landings. As defined in the Shuttle Flight Rules (FRs), there are peak wind thresholds that cannot be exceeded in order to ensure the safety of the shuttle during landing operations. The National Weather Service Spaceflight Meteorology Group (SMG) is responsible for weather forecasts for all shuttle landings. They indicate peak winds are a challenging parameter to forecast. To alleviate the difficulty in making such wind forecasts, the Applied Meteorology Unit (AMTJ) developed a personal computer based graphical user interface (GUI) for displaying peak wind climatology and probabilities of exceeding peak-wind thresholds for the Shuttle Landing Facility (SLF) at Kennedy Space Center. However, the shuttle must land at Edwards Air Force Base (EAFB) in southern California when weather conditions at Kennedy Space Center in Florida are not acceptable, so SMG forecasters requested that a similar tool be developed for EAFB. Marshall Space Flight Center (MSFC) personnel archived and performed quality control of 2-minute average and 10-minute peak wind speeds at each tower adjacent to the main runway at EAFB from 1997- 2004. They calculated wind climatologies and probabilities of average peak wind occurrence based on the average speed. The climatologies were calculated for each tower and month, and were stratified by hour, direction, and direction/hour. For the probabilities of peak wind occurrence, MSFC calculated empirical and modeled probabilities of meeting or exceeding specific 10-minute peak wind speeds using probability density functions. The AMU obtained and reformatted the data into Microsoft Excel PivotTables, which allows users to display different values with point-click-drag techniques. The GUT was then created from the PivotTables using Visual Basic for Applications code. The GUI is run through a macro within Microsoft Excel and allows forecasters to quickly display and

  2. Two-Phonon Absorption

    ERIC Educational Resources Information Center

    Hamilton, M. W.

    2007-01-01

    A nonlinear aspect of the acousto-optic interaction that is analogous to multi-photon absorption is discussed. An experiment is described in which the second-order acousto-optically scattered intensity is measured and found to scale with the square of the acoustic intensity. This experiment using a commercially available acousto-optic modulator is…

  3. Total absorption Cherenkov spectrometers

    NASA Astrophysics Data System (ADS)

    Malinovski, E. I.

    2015-05-01

    A short review of 50 years of work done with Cherenkov detectors in laboratories at the Lebedev Physical Institute is presented. The report considers some issues concerning the use of Cherenkov total absorption counters based on lead glass and heavy crystals in accelerator experiments.

  4. Cholesterol Absorption and Metabolism.

    PubMed

    Howles, Philip N

    2016-01-01

    Inhibitors of cholesterol absorption have been sought for decades as a means to treat and prevent cardiovascular diseases (CVDs) associated with hypercholesterolemia. Ezetimibe is the one clear success story in this regard, and other compounds with similar efficacy continue to be sought. In the last decade, the laboratory mouse, with all its genetic power, has become the premier experimental model for discovering the mechanisms underlying cholesterol absorption and has become a critical tool for preclinical testing of potential pharmaceutical entities. This chapter briefly reviews the history of cholesterol absorption research and the various gene candidates that have come under consideration as drug targets. The most common and versatile method of measuring cholesterol absorption is described in detail along with important considerations when interpreting results, and an alternative method is also presented. In recent years, reverse cholesterol transport (RCT) has become an area of intense new interest for drug discovery since this process is now considered another key to reducing CVD risk. The ultimate measure of RCT is sterol excretion and a detailed description is given for measuring neutral and acidic fecal sterols and interpreting the results. PMID:27150091

  5. Lipids: Absorption and transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to the hydrophobic nature of lipids, dietary fat is handled differently than protein or carbohydrate with respect with digestion and absorption. Dietary fats are broken down throughout the gastrointestinal system. A unique group of enzymes and cofactors allows this process to proceed in an eff...

  6. ZINC ABSORPTION BY INFANTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zinc is a vital mineral in human nutrition, and rare cases of overt zinc deficiency are well described in term and preterm infants. A variety of methods have been developed to assess zinc absorption, retention, and balance in humans, either using mass (metabolic) balance or stable isotope-based METH...

  7. Absorption driven focus shift

    NASA Astrophysics Data System (ADS)

    Harrop, N.; Wolf, S.; Maerten, O.; Dudek, K.; Ballach, S.; Kramer, R.

    2016-03-01

    Modern high brilliance near infrared lasers have seen a tremendous growth in applications throughout the world. Increased productivity has been achieved by higher laser power and increased brilliance of lasers. Positive impacts on the performance and costs of parts are opposed to threats on process stability and quality, namely shift of focus position over time. A high initial process quality will be reduced by contamination of optics, eventually leading to a focus shift or even destruction of the optics. Focus analysis at full power of multi-kilowatt high brilliance lasers is a very demanding task because of high power densities in the spot and the high power load on optical elements. With the newly developed high power projection optics, the High-Power Micro-Spot Monitor High Brilliance (HP-MSM-HB) is able to measure focus diameter as low as 20 μm at power levels up to 10 kW at very low internal focus shift. A main driving factor behind thermally induced focus shift is the absorption level of the optical element. A newly developed measuring system is designed to determine the relative absorption level in reference to a gold standard. Test results presented show a direct correlation between absorption levels and focus shift. The ability to determine the absorption level of optical elements as well as their performance at full processing power before they are put to use, enables a high level of quality assurance for optics manufacturers and processing head manufacturers alike.

  8. Peak Pc Prediction in Conjunction Analysis: Conjunction Assessment Risk Analysis. Pc Behavior Prediction Models

    NASA Technical Reports Server (NTRS)

    Vallejo, J.J.; Hejduk, M.D.; Stamey, J. D.

    2015-01-01

    Satellite conjunction risk typically evaluated through the probability of collision (Pc). Considers both conjunction geometry and uncertainties in both state estimates. Conjunction events initially discovered through Joint Space Operations Center (JSpOC) screenings, usually seven days before Time of Closest Approach (TCA). However, JSpOC continues to track objects and issue conjunction updates. Changes in state estimate and reduced propagation time cause Pc to change as event develops. These changes a combination of potentially predictable development and unpredictable changes in state estimate covariance. Operationally useful datum: the peak Pc. If it can reasonably be inferred that the peak Pc value has passed, then risk assessment can be conducted against this peak value. If this value is below remediation level, then event intensity can be relaxed. Can the peak Pc location be reasonably predicted?

  9. Mineral resources of the Redcloud Peak and Handies Peak Wilderness Study Areas, Hinsdale County, Colorado

    SciTech Connect

    Sanford, R.F.; Grauch, R.I.; Hon, K.; Bove, D.J.; Grauch, V.J.S.; Korzeb, S.L.

    1987-01-01

    The Redcloud Peak and Handies Peak Wilderness Study Areas are located 2-12 mi southwest of Lake City, CO. Much of the study areas has high mineral resource potential for precious and base metals in various ore deposit types. The rest of the study areas has moderate potential for these commodities. Two areas in the Redcloud Peak study area have moderate potential for molybdenum and copper in quartz monzonite-associated porphyry deposits. Part of the Handies Peak study area has moderate potential for molybdenum in granite-related porphyry deposits. The southwestern part of the Redcloud Peak study area has high potential for uranium in vein-type deposits. Moderate potential for this commodity extends over other parts of both study areas. The mineral resource potential for gold and silver (in clastic-sediment-hosted disseminated-type epithermal deposits) is low in those parts of both study areas underlain by the Henson Member of the Silverton Volcanics. The mineral and energy resource potential for aluminum (in alunite deposits), uranium (in disseminated deposits), and geothermal sources is low throughout both study areas. Based on currently available data, there is no energy resource potential for coal, oil, and natural gas. The study areas have no identified resources.

  10. Twin Peaks in 360-degree panorama

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The prominent hills dubbed 'Twin Peaks' approximately 1-2 kilometers away were imaged by the Imager for Mars Pathfinder (IMP) as part of a 360-degree color panorama, taken over sols 8, 9 and 10. A lander petal and deflated airbag are at the bottom of the image.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

  11. NMR solvent peak suppression by nonlinear excitation

    NASA Astrophysics Data System (ADS)

    Levitt, Malcolm H.

    1988-03-01

    Most existing NMR solvent peak suppression sequences provide a satisfactory dependence of the intensity of excited signals on frequency but poor phase characteristics. In practice this leads to spectral distortions which generally become more severe as the frequency selectivity of the sequence is increased. However, it is shown that by working well outside the linear response regime, excitation schemes which combine high frequency selectivity with good phase properties may be devised. Sequences of six rectangular radio-frequency pulses were discovered using a combination of coherent averaging theory to treat the near-resonant behavior and numerical simulation further from resonance. Extensive use of symmetry greatly simplifies both the coherent averaging calculations and the numerical simulations. The new pulse sequences have been given the acronym NERO (nonlinear excitation rejecting on-resonance). Experimental spectra of an enzyme in dilute aqueous solution are shown.

  12. BUFFALO PEAKS WILDERNESS STUDY AREA, COLORADO.

    USGS Publications Warehouse

    Hedlund, D.C.; Wood, R.H.

    1984-01-01

    Field investigations were conducted to evaluate the mineral-resource potential of the Buffalo Peaks Wilderness Study Area, Colorado. On the basis of this study there is a probable mineral-resource potential for silver vein and bedding replacement deposits along the Weston Pass fault zone, for hydrothermal vein-type uranium deposits in the vicinity of the Parkdale iron pit, and for gold vein deposits in the parts of the Granite and Four Mile districts that are within the wilderness study area. A probable barite resource potential occurs at Rough and Tumbling Creek and near Spring Creek on the east side of the study area. There is little promise for the occurrence of energy resources.

  13. Sample distribution in peak mode isotachophoresis

    SciTech Connect

    Rubin, Shimon; Schwartz, Ortal; Bercovici, Moran

    2014-01-15

    We present an analytical study of peak mode isotachophoresis (ITP), and provide closed form solutions for sample distribution and electric field, as well as for leading-, trailing-, and counter-ion concentration profiles. Importantly, the solution we present is valid not only for the case of fully ionized species, but also for systems of weak electrolytes which better represent real buffer systems and for multivalent analytes such as proteins and DNA. The model reveals two major scales which govern the electric field and buffer distributions, and an additional length scale governing analyte distribution. Using well-controlled experiments, and numerical simulations, we verify and validate the model and highlight its key merits as well as its limitations. We demonstrate the use of the model for determining the peak concentration of focused sample based on known buffer and analyte properties, and show it differs significantly from commonly used approximations based on the interface width alone. We further apply our model for studying reactions between multiple species having different effective mobilities yet co-focused at a single ITP interface. We find a closed form expression for an effective-on rate which depends on reactants distributions, and derive the conditions for optimizing such reactions. Interestingly, the model reveals that maximum reaction rate is not necessarily obtained when the concentration profiles of the reacting species perfectly overlap. In addition to the exact solutions, we derive throughout several closed form engineering approximations which are based on elementary functions and are simple to implement, yet maintain the interplay between the important scales. Both the exact and approximate solutions provide insight into sample focusing and can be used to design and optimize ITP-based assays.

  14. Neuron absorption study and mid-IR optical excitations

    NASA Astrophysics Data System (ADS)

    Guo, Dingkai; Chen, Xing; Vadala, Shilpa; Leach, Jennie; Kostov, Yordan; Bewley, William W.; Kim, Chul-Soo; Kim, Mijin; Canedy, Chadwick L.; Merritt, Charles D.; Vurgaftman, Igor; Meyer, Jerry R.; Choa, Fow-Sen

    2012-02-01

    Neuronal optical excitation can provide non-contacting tools to explore brain circuitry and a durable stimulation interface for cardiac pacing and visual as well as auditory sensory neuronal stimulation. To obtain accurate absorption spectra, we scan the transmission of neurons in cell culture medium, and normalize it by subtracting out the absorption spectrum of the medium alone. The resulting spectra show that the main neuronal absorption peaks are in the 3000- 6000nm band, although there is a smaller peak near 1450nm. By coupling the output of a 3μm interband cascade laser (ICL) into a mid-IR fluorozirconate fiber, we can effectively deliver more than 1J/cm2 photon intensity to the excitation site for neuronal stimulation.

  15. DOUBLE-PEAKED NARROW-LINE ACTIVE GALACTIC NUCLEI. II. THE CASE OF EQUAL PEAKS

    SciTech Connect

    Smith, K. L.; Shields, G. A.; Salviander, S.; Stevens, A. C.; Rosario, D. J. E-mail: shields@astro.as.utexas.edu E-mail: acs0196@mail.utexas.edu

    2012-06-10

    Active galactic nuclei (AGNs) with double-peaked narrow lines (DPAGNs) may be caused by kiloparsec-scale binary AGNs, bipolar outflows, or rotating gaseous disks. We examine the class of DPAGNs in which the two narrow-line components have closely similar intensity as being especially likely to involve disks or jets. Two spectroscopic indicators support this likelihood. For DPAGNs from Smith et al., the 'equal-peaked' objects (EPAGNs) have [Ne V]/[O III]ratios lower than for a control sample of non-double-peaked AGNs. This is unexpected for a pair of normal AGNs in a galactic merger, but may be consistent with [O III] emission from a rotating ring with relatively little gas at small radii. Also, [O III]/H{beta} ratios of the redshifted and blueshifted systems in the EPAGN are more similar to each other than in a control sample, suggestive of a single ionizing source and inconsistent with the binary interpretation.

  16. Local inversion-symmetry breaking controls the boson peak in glasses and crystals

    NASA Astrophysics Data System (ADS)

    Milkus, R.; Zaccone, A.

    2016-03-01

    It is well known that amorphous solids display a phonon spectrum where the Debye ˜ω2 law at low frequency melds into an anomalous excess-mode peak (the boson peak) before entering a quasilocalized regime at higher frequencies dominated by scattering. The microscopic origin of the boson peak has remained elusive despite various attempts to put it in a clear connection with structural disorder at the atomic/molecular level. Using numerical calculations on model systems, we show that the microscopic origin of the boson peak is directly controlled by the local breaking of center-inversion symmetry. In particular, we find that both the boson peak and the nonaffine softening of the material display a strong correlation with a new order parameter describing the local inversion symmetry of the lattice. The standard bond-orientational order parameter, instead, is shown to be inadequate and cannot explain the boson peak in randomly-cut crystals with perfect bond-orientational order. Our results bring a unifying understanding of the boson peak anomaly for model glasses and defective crystals in terms of a universal local symmetry-breaking principle of the lattice.

  17. Infrared Absorption Spectroscopy Measurement of SOx using Tunable Infrared Laser

    NASA Astrophysics Data System (ADS)

    Fukuchi, Tetsuo

    The absorption characteristics of sulfur dioxide (SO2) and sulfur trioxide (SO3) in the infrared region were measured using a quantum cascade laser and an absorption cell of length 1 m heated to 150°C. The laser was scanned over the wavelength range 6.9-7.4 μm, which included the absorption bands of SO2 and SO3. Measurement results showed that the absorption bands of SO2 and SO3 partially overlapped, with peaks at 7.28 μm and 7.35 μm for SO2 and 7.14 μm and 7.25 μm for SO3. These results showed the possbility of using infrared laser absorption spectroscopy for measurement of sulfur oxides (SOx) in flue gas. For SO3 measurement, infrared absorption spectroscopy was shown to be more suitable than ultraviolet absorption spectroscopy. The absorption characteristics of open air in the same wavelength region showed that the interference due to water vapor must be efficiently removed to perform SOx measurement in flue gas.

  18. Absorption and pharmacokinetics of phenylbutazone in Welsh Mountain ponies.

    PubMed

    Maitho, T E; Lees, P; Taylor, J B

    1986-03-01

    The disposition of phenylbutazone (4.4 mg/kg), administered intravenously to six Welsh Mountain ponies, was described by a two-compartment open model. Pharmacokinetic parameters were not significantly different after morning dosing in comparison with afternoon dosing. When phenylbutazone (4.4 mg/kg) was administered orally to the same ponies, marked variations in time to peak concentrations were produced with different feeding schedules. When access to hay was permitted before and after dosing, the mean time to peak concentration was 13.2 +/- 1.2 h and double peaks in the plasma concentration-time curve were common. Double peaks were also encountered when phenylbutazone was given to ponies deprived of food prior to, and allowed access to hay after, dosing. In this circumstance, mean times to peak concentration were much shorter (3.8 +/- 1.3 h after morning dosing and 5.3 +/- 1.5 h followed afternoon dosing). Absorption was more regular and double peaks were less apparent when food was withheld both before and after dosing. In order to explain these findings, it is tentatively postulated that, whereas some of the administered dose of phenylbutazone may be absorbed quickly, some may become adsorbed on to the feed and subsequently released by fermentative digestion in the large intestine and/or caecum. The consequences of delayed absorption in fed animals for toxicity and clinical efficacy, and for the use of phenylbutazone in equestrian sports, are considered. Delayed absorption in ponies given access to hay was not accompanied by a significant reduction in total absorption. Bioavailability was estimated to be approximately 69% in fed and 78% in unfed ponies. Estimates of bioavailability gave similar values for morning (72%) and afternoon (71%) dosing. PMID:3701913

  19. 69. INTERIOR VIEW OF THE ABSORPTION TOWER BUILDING, ABSORPTION TOWER ...

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

    69. INTERIOR VIEW OF THE ABSORPTION TOWER BUILDING, ABSORPTION TOWER UNDER CONSTRUCTION. (DATE UNKNOWN). - United States Nitrate Plant No. 2, Reservation Road, Muscle Shoals, Muscle Shoals, Colbert County, AL

  20. Children's cancer centers

    MedlinePlus

    Pediatric cancer center; Pediatric oncology center; Comprehensive cancer center ... from getting the care your child needs. The Pediatric Oncology Resource Center has links and contact information ...

  1. Quantum Entanglement Molecular Absorption Spectrum Simulator

    NASA Technical Reports Server (NTRS)

    Nguyen, Quang-Viet; Kojima, Jun

    2006-01-01

    Quantum Entanglement Molecular Absorption Spectrum Simulator (QE-MASS) is a computer program for simulating two photon molecular-absorption spectroscopy using quantum-entangled photons. More specifically, QE-MASS simulates the molecular absorption of two quantum-entangled photons generated by the spontaneous parametric down-conversion (SPDC) of a fixed-frequency photon from a laser. The two-photon absorption process is modeled via a combination of rovibrational and electronic single-photon transitions, using a wave-function formalism. A two-photon absorption cross section as a function of the entanglement delay time between the two photons is computed, then subjected to a fast Fourier transform to produce an energy spectrum. The program then detects peaks in the Fourier spectrum and displays the energy levels of very short-lived intermediate quantum states (or virtual states) of the molecule. Such virtual states were only previously accessible using ultra-fast (femtosecond) laser systems. However, with the use of a single-frequency continuous wave laser to produce SPDC photons, and QEMASS program, these short-lived molecular states can now be studied using much simpler laser systems. QE-MASS can also show the dependence of the Fourier spectrum on the tuning range of the entanglement time of any externally introduced optical-path delay time. QE-MASS can be extended to any molecule for which an appropriate spectroscopic database is available. It is a means of performing an a priori parametric analysis of entangled photon spectroscopy for development and implementation of emerging quantum-spectroscopic sensing techniques. QE-MASS is currently implemented using the Mathcad software package.

  2. Seismic scattering and absorption mapping of debris flows, feeding paths, and tectonic units at Mount St. Helens volcano

    NASA Astrophysics Data System (ADS)

    De Siena, Luca; Calvet, Marie; Watson, Keira J.; Jonkers, Art R. D.; Thomas, Christine

    2016-04-01

    Frequency-dependent peak-delay times and coda quality factors have been used jointly to separate seismic absorption from scattering quantitatively in Earth media at regional and lithospheric scale; to this end, we measure and map these two quantities at Mount St. Helens volcano. The results show that we can locate and characterise volcanic and geological structures using their unique contribution to seismic attenuation. At 3 Hz a single high-scattering and high-absorption anomaly outlines the debris flows that followed the 1980 explosive eruption, as deduced by comparison with remote sensing imagery. The flows overlay a NNW-SSE interface, separating rocks of significant varying properties down to 2-4 km, and coinciding with the Saint Helens Seismic Zone. High-scattering and high-absorption anomalies corresponding to known locations of magma emplacement follow this signature under the volcano, showing the important interconnections between its feeding systems and the regional tectonic boundaries. With frequency increasing from 6 to 18 Hz the NNW-SSE tectonic/feeding trends rotate around an axis centered on the volcano in the direction of the regional-scale magmatic arc (SW-NE). While the aseismic high-scattering region WSW of the volcano shows no evidence of high absorption, the regions of highest-scattering and absorption are consistently located at all frequencies under either the eastern or the south-eastern flank of the volcanic edifice. From the comparison with the available geological and geophysical information we infer that these anomalies mark both the location and the trend of the main feeding systems at depths greater than 4 km.

  3. Seismic scattering and absorption mapping of debris flows, feeding paths, and tectonic units at Mount St. Helens volcano

    NASA Astrophysics Data System (ADS)

    De Siena, L.; Calvet, M.; Watson, K. J.; Jonkers, A. R. T.; Thomas, C.

    2016-05-01

    Frequency-dependent peak-delay times and coda quality factors have been used jointly to separate seismic absorption from scattering quantitatively in Earth media at regional and continental scale; to this end, we measure and map these two quantities at Mount St. Helens volcano. The results show that we can locate and characterize volcanic and geological structures using their unique contribution to seismic attenuation. At 3 Hz a single high-scattering and high-absorption anomaly outlines the debris flows that followed the 1980 explosive eruption, as deduced by comparison with remote sensing imagery. The flows overlay a NNW-SSE interface, separating rocks of significant varying properties down to 2-4 km, and coinciding with the St. Helens Seismic Zone. High-scattering and high-absorption anomalies corresponding to known locations of magma emplacement follow this signature under the volcano, showing the important interconnections between its feeding systems and the regional tectonic boundaries. With frequency increasing from 6 to 18 Hz the NNW-SSE tectonic/feeding trends rotate around an axis centered on the volcano in the direction of the regional-scale magmatic arc (SW-NE). While the aseismic high-scattering region WSW of the volcano shows no evidence of high absorption, the regions of highest-scattering and absorption are consistently located at all frequencies under either the eastern or the south-eastern flank of the volcanic edifice. From the comparison with the available geological and geophysical information we infer that these anomalies mark both the location and the trend of the main feeding systems at depths greater than 4 km.

  4. Peak phosphorus - peak food? The need to close the phosphorus cycle.

    PubMed

    Rhodes, Christopher J

    2013-01-01

    The peak in the world production of phosphorus has been predicted to occur in 2033, based on world reserves of rock phosphate (URR) reckoned at around 24,000 million tonnes (Mt), with around 18,000 Mt remaining. This figure was reckoned-up to 71,000 Mt, by the USGS, in 2012, but a production maximum during the present century is still highly probable. There are complex issues over what the demand will be for phosphorus in the future, as measured against a rising population (from 7 billion to over 9 billion in 2050), and a greater per capita demand for fertiliser to grow more grain, in part to feed animals and meet a rising demand for meat by a human species that is not merely more populous but more affluent. As a counterweight to this, we may expect that greater efficiencies in the use of phosphorus - including recycling from farms and of human and animal waste - will reduce the per capita demand for phosphate rock. The unseen game changer is peak oil, since phosphate is mined and recovered using machinery powered by liquid fuels refined from crude oil. Hence, peak oil and peak phosphorus might appear as conjoined twins. There is no unequivocal case that we can afford to ignore the likelihood of a supply-demand gap for phosphorus occurring sometime this century, and it would be perilous to do so. PMID:23901632

  5. Peaking at Zero: Null Subjects and Other Indicators of Peak in Konni Texts.

    ERIC Educational Resources Information Center

    Cahill, Mike

    An analysis of story telling in Konni, a language spoken in Ghana, focused on how the climax of a story is characterized. The texts studied are six oral folk tales; two are appended, and portions of all are used as illustrations in the text of the report. First, the definition and characteristics of "peak," or climax of a story are discussed. This…

  6. Chaotic systems with absorption.

    PubMed

    Altmann, Eduardo G; Portela, Jefferson S E; Tél, Tamás

    2013-10-01

    Motivated by applications in optics and acoustics we develop a dynamical-system approach to describe absorption in chaotic systems. We introduce an operator formalism from which we obtain (i) a general formula for the escape rate κ in terms of the natural conditionally invariant measure of the system, (ii) an increased multifractality when compared to the spectrum of dimensions D(q) obtained without taking absorption and return times into account, and (iii) a generalization of the Kantz-Grassberger formula that expresses D(1) in terms of κ, the positive Lyapunov exponent, the average return time, and a new quantity, the reflection rate. Simulations in the cardioid billiard confirm these results. PMID:24138240

  7. Extrasolar Planet Transits Observed at Kitt Peak National Observatory

    NASA Technical Reports Server (NTRS)

    Sada, Pedro V.; Jennings, Donald E.; Deming, Drake; Jennings, Donald E.; Jackson, Brian; Hamilton, Catrina M.; Fraine, Jonathan; Peterson, Steven W.; Haase, Flynn; Bays, Kevin; Lunsford, Allen; O'Gorman, Eamon

    2012-01-01

    We obtained J-, H-, and JH-band photometry of known extrasolar planet transiting systems at the 2.1 m Kitt Peak National Observatory Telescope using the FLAMINGOS infrared camera between 2008 October and 2011 October. From the derived light curves we have extracted the midtransit times, transit depths and transit durations for these events. The precise midtransit times obtained help improve the orbital periods and also constrain transit-time variations of the systems. For most cases the published system parameters successfully accounted for our observed light curves, but in some instances we derive improved planetary radii and orbital periods. We complemented our 2.1 m infrared observations using CCD z0-band and B-band photometry (plus two H(alpha) filter observations) obtained with the Kitt Peak Visitor Center Telescope, and with four H-band transits observed in 2007 October with the NSO's 1.6 m McMath-Pierce Solar Telescope. The principal highlights of our results are (1) Our ensemble of J-band planetary radii agree with optical radii, with the best-fit relation being RpRJ0:0017 0:979RpRvis. (2) We observe starspot crossings during the transit of WASP-11HAT-P-10. (3) We detect starspot crossings by HAT-P-11b (Kepler-3b), thus confirming that the magnetic evolution of the stellar active regions can be monitored even after the Kepler mission has ended. (4) We confirm a grazing transit for HAT-P-27WASP-40. In total, we present 57 individual transits of 32 known exoplanet systems.

  8. NOx control buys to peak in `98

    SciTech Connect

    McIlvaine, R.W.

    1995-10-01

    Titles I and IV of the Clean Air Act provide the legislative framework for a huge NOx reduction program now in operation. This reduction will have a substantial effect in reducing ground-level ozone. A new McIlvaine report concludes that US utilities and industrial companies during the next 10 years will spend more than $800 million annually to meet CAA`s NOx-control regulations. Much of that investment will be for low-NOx burners, which minimize NOx formation. Many utilities and industrial boilers can be retrofitted with a new generation of burners; however, this technology achieves less than 50% NOx reduction. Post-combustion technologies, such as selective catalytic reduction and selective noncatalytic reduction, can reduce NOx as much as 90%. Therefore, plants needing greater NOx reduction will use post-combustion technologies, often in combination with low-NOx burners. The peak order year for NOx-control equipment will be 1998, primarily because Title IV of CAA requires utilities to comply by 2000. Many industrial sources also will be ordering equipment in 1998.

  9. Pathways of iron absorption.

    PubMed

    Conrad, Marcel E; Umbreit, Jay N

    2002-01-01

    Iron is vital for all living organisms but excess iron can be lethal because it facilitates free radical formation. Thus iron absorption is carefully regulated to maintain an equilibrium between absorption and body loss of iron. In countries where meat is a significant part of the diet, most body iron is derived from dietary heme because heme binds few of the dietary chelators that bind inorganic iron. Uptake of heme into enterocytes occurs as a metalloporphyrin in an endosomal process. Intracellular iron is released from heme by heme oxygenase to enter plasma as inorganic iron. Ferric iron is absorbed via a beta(3) integrin and mobilferrin pathway (IMP) which is unshared with other nutritional metals. Ferrous iron uptake is facilitated by a DMT-1 pathway which is shared with manganese. In the iron deficient gut, large quantities of both mobilferrin and DMT-1 are found in goblet cells and intraluminal mucins suggesting that they are secreted with mucin into the intestinal lumen to bind iron to facilitate uptake by the cells. In the cytoplasm, IMP and DMT associate in a large protein complex called paraferritin which serves as a ferrireductase. Paraferritin solublizes iron binding proteins and reduces iron to make iron available for production of iron containing proteins such as heme. Iron uptake by intestinal absorptive cells is regulated by the iron concentration within the cell. Except in hemochromatosis it remains in equilibrium with total body stores via transferrin receptors on the basolateral membrane of absorptive cells. Increased intracellular iron either up-regulates or satiates iron binding proteins on regulatory proteins to alter their location in the intestinal mucosa. PMID:12547224

  10. Evolution of a reaction center in an explosive material

    NASA Technical Reports Server (NTRS)

    Jackson, T. L.; Kapila, A. K.; Stewart, D. S.

    1989-01-01

    Consideration is given to the spatial structure and temporal evolution of a reaction center for a model involving Arrhenius kinetics. The center, which is characterized by peaks in pressure and temperature with little diminution in local density, is found to have one of two possible self-similar structures. The analysis uses a combination of asymptotics and numerics and terminates when pressure and temperature in the reaction center have peaked.

  11. Relic Neutrino Absorption Spectroscopy

    SciTech Connect

    Eberle, b

    2004-01-28

    Resonant annihilation of extremely high-energy cosmic neutrinos on big-bang relic anti-neutrinos (and vice versa) into Z-bosons leads to sizable absorption dips in the neutrino flux to be observed at Earth. The high-energy edges of these dips are fixed, via the resonance energies, by the neutrino masses alone. Their depths are determined by the cosmic neutrino background density, by the cosmological parameters determining the expansion rate of the universe, and by the large redshift history of the cosmic neutrino sources. We investigate the possibility of determining the existence of the cosmic neutrino background within the next decade from a measurement of these absorption dips in the neutrino flux. As a by-product, we study the prospects to infer the absolute neutrino mass scale. We find that, with the presently planned neutrino detectors (ANITA, Auger, EUSO, OWL, RICE, and SalSA) operating in the relevant energy regime above 10{sup 21} eV, relic neutrino absorption spectroscopy becomes a realistic possibility. It requires, however, the existence of extremely powerful neutrino sources, which should be opaque to nucleons and high-energy photons to evade present constraints. Furthermore, the neutrino mass spectrum must be quasi-degenerate to optimize the dip, which implies m{sub {nu}} 0.1 eV for the lightest neutrino. With a second generation of neutrino detectors, these demanding requirements can be relaxed considerably.

  12. X-Ray Absorption Fine Structure Investigation of Copper(II) Mixed Ligand Complexes with Pyridinedicarboxylic Acid as Primary Ligand

    NASA Astrophysics Data System (ADS)

    Dar, D. Ah.; Gaur, A.; Soni, B.; Shrivastava, B. D.; Prasad, J.; Srivastava, K.; Jha, S. N.; Bhattacharyya, D.

    2015-05-01

    The X-ray absorption fine structure (XAFS) spectra at the K-edge of the copper complexes Cu(PDC)(Mim)3 H2O ( 1) and Cu(PDC)2(EA)2H2O ( 2) (where PDC - Pyridine-2,3-dicarboxylic acid, Mim - 2-methylimidazole, and EA - ethyl acetate) have been investigated. The experimental extended X-ray absorption fine structure data of complex 1 have been analyzed by fitting the theoretical model generated from its own crystallographic data. The crystallographic data for complex 2 are not available. It has been found by comparing the intensity of the pre-edge peaks and X-ray absorption near edge structure features of complexes 1 and 2 that both complexes possess square pyramidal geometry around the copper centers and thus complex 2 is analogous to complex 1. Hence, the theoretical model generated for complex 1 has been fitted to the experimental EXAFS data of complex 2 to determine the structural parameters of complex 2. The coordination geometry of both complexes has been depicted. Further, the chemical shifts have been used to determine the oxidation state as well as to estimate the effective nuclear charge on the copper atom.

  13. CO2 Absorption Spectroscopy and Climate Change

    NASA Astrophysics Data System (ADS)

    Feldman, Daniel; Mlawer, Eli; Mlynczak, Martin; Gero, Jon; Collins, William; Torn, Margaret

    2014-03-01

    Most of the absorption, and therefore radiative forcing, due to increased atmospheric CO2 occurs in line wings, so utilizing an accurate line shape is necessary for climate science. Recent advances in CO2 absorption spectroscopy have been incorporated into benchmark line-by-line radiative transfer models. These updates include the Energy Corrected Sudden Approximation to represent isolated line profiles, line mixing, and line clusters. The CO2 line profiles are sub-Lorentzian and are explicitly modeled up to 25 cm-1 from each line's center. Consistent continuum absorption is implemented over the remainder of the profile except for modest empirical adjustments based on observations. Thus, line-by-line models calculate the absorption effects of CO2 that agree with theory and measurements. This is validated with long-term spectroscopic measurements from the ARM program's AERI instrument. This spectroscopy trains computationally-efficient correlated-k methods for climate model radiative transfer, but they overpredict instantaneous radiative forcing from doubled CO2 by approximately 7% in part because they have larger errors handling the impact of increased CO2 in the stratosphere than the troposphere. The implications of this can be tested with supercomputers. This work was supported by the Director, Office of Science, Office of Biol. & Env. Res., Clim. & Env. Sci. Div., of the U.S. D.O.E., Contract No. DE-AC02-05CH11231 as part of the Atmos. Sys. Res.

  14. A simple parameterization of ozone infrared absorption for atmospheric heating rate calculations

    NASA Technical Reports Server (NTRS)

    Rosenfield, Joan E.

    1991-01-01

    A simple parameterization of ozone absorption in the 9.6-micron region which is suitable for two- and three-dimensional stratospheric and tropospheric models is presented. The band is divided into two parts, a brand center region and a band wing region, grouping together regions for which the temperature dependence of absorption is similar. Each of the two regions is modeled with a function having the form of the Goody random model, with pressure and temperature dependent band parameters chosen by empirically fitting line-by-line equivalent widths for pressures between 0.25 and 1000 mbar and ozone absorber amounts between 1.0 x 10 to the -7th and 1.0 cm atm. The model has been applied to calculations of atmospheric heating rates using an absorber amount weighted mean pressure and temperature along the inhomogeneous paths necessary for flux computations. In the stratosphere, maximum errors in the heating rates relative to line-by-line calculations are 0.1 K/d, or 5 percent of the peak cooling at the stratopause. In the troposphere the errors are at most 0.005 K/d.

  15. On the Origin of the Wide HI Absorption Line Towards Sgr A *

    NASA Astrophysics Data System (ADS)

    Dwarakanath, K. S.; Goss, W. M.; Zhao, J. H.; Lang, C. C.

    2004-09-01

    We have imaged a region of ~5 extent surrounding Sgr A* in the HI 21 cm-line absorption using the Very Large Array. A Gaussian decomposition of the optical depth spectra at positions within ~2(~5 pcat 8.5 kpc) of Sgr A* detects a wide linw underlying the many narrow absorption lines. The wide line has a mean peak optical depth of 0.32 ± 0.12 centered at a mean velocity of Vlsr = -4 ± 15 km s-1. The mean full width half maximum is 119 ± 42 km s-1. Such a wide line is absent in the spectra at positions beyond ~2 from Sgr A*. The position-velocity diagrams do not reveal any diffuse feature which could be attributed to a large number of HI clouds along the line of sight to Sgr A*. Consequently, the wide line has no implications either to a global population of shocked HI clouds in the Galaxy or to the energetics of the interstellar medium as was earlier thought.

  16. An analysis of Super typhoon Rammasun's(2014) peak intensity

    NASA Astrophysics Data System (ADS)

    Cai, Qinbo; Xu, Yinglong

    2016-04-01

    Super typhoon Rammasun (2014) made landfall over Hainan Island, China, at 0730UTC 18 July 2014. Due to the damage of the anemometers, the Automatic Weather Stations (AWS) and the bouy which by Rammasun passed, failed to obtain its peak wind. Lack of the direct evident, in real-time monitoring, its peak intensities were given by 110kts (.i.e. 60m/s)/910hPa,135kts/922hPa , and 90kts/935hPa based on Dvorak technique , which were made by China Meteorological Administration (CMA),Joint Typhoon Warning Center(JTWC), and Japan Meteorological Agency (JMA) respectively. However, a minimum pressure of 881.2hPa recorded by a barometer which located at Qixhou island (19.982︒N,111.269︒E) while Rammasun approaching, indicates that its intensity was under estimated. By using observation data such as AWS, satellite, Doppler radar and wind tower near the ground, this study performs a detail evaluation to obtain its actual intensity. At 0521UTC, Qizhou Island station recorded 881.2hPa of the minimum station pressure and 899.2hPa of minimum sea level pressure (MSLP) while the anemometer had been destroyed. These are the lowest records in Chinese history and also are ones of the global lowest pressures obtained directly by barometer. It is evident that Rammasun's eyewall did not pass across Qizhou Island directly, so the actual MSLP should be lower than 899.2hPa. By applying wind-pressure relationship, it is reckoned that the reasonable MSLP and peak wind of Rammasun should be 888hPa and 70-76m/s, which makes Rammasun the strongest typhoon ever made landfall in China's history. In order to intuitively investigate the real intensity of Ramasun, eyewall structures are compared with some historical extreme typhoons (hurricanes) such as Saomai(2006), Haiyan(2013) and Katrina(2005). Satellite images show that the dense overcast convection strength of Rammasun is stronger than those when Saomai and Katrina were in their peak intensities and before landing, but weaker than Haiyan. The

  17. Color-center production and recovery in electron-irradiated magnesium aluminate spinel and ceria

    NASA Astrophysics Data System (ADS)

    Costantini, Jean-Marc; Lelong, Gérald; Guillaumet, Maxime; Weber, William J.; Takaki, Seiya; Yasuda, Kazuhiro

    2016-08-01

    Single crystals of magnesium aluminate spinel (MgAl2O4) with (1 0 0) or (1 1 0) orientations and cerium dioxide or ceria (CeO2) were irradiated by 1.0 MeV and 2.5 MeV electrons in a high-fluence range. Point-defect production was studied by off-line UV–visible optical spectroscopy after irradiation. For spinel, regardless of both crystal orientation and electron energy, two characteristic broad bands centered at photon energies of 5.4 eV and 4.9 eV were assigned to F and F+ centers (neutral and singly ionized oxygen vacancies), respectively, on the basis of available literature data. No clear differences in color-center formation were observed for the two crystal orientations. Using calculations from displacement cross sections by elastic collisions, these results are consistent with a very large threshold displacement energy (200 eV) for oxygen atoms at room temperature. A third very broad band centered at 3.7 eV might be attributed either to an oxygen hole center (V-type center) or an F2 dimer center (oxygen di-vacancy). The onset of recovery of these color centers took place at 200 °C with almost full bleaching at 600 °C. Activation energies (~0.3–0.4 eV) for defect recovery were deduced from the isochronal annealing data by using a first-order kinetics analysis. For ceria, a sub-band-gap absorption feature, which peaked at ~3.1 eV, was recorded for 2.5 MeV electron irradiation only. Assuming a ballistic process, we suggest that the latter defect might result from cerium atom displacement on the basis of computed cross sections.

  18. Color-center production and recovery in electron-irradiated magnesium aluminate spinel and ceria.

    PubMed

    Costantini, Jean-Marc; Lelong, Gérald; Guillaumet, Maxime; Weber, William J; Takaki, Seiya; Yasuda, Kazuhiro

    2016-08-17

    Single crystals of magnesium aluminate spinel (MgAl2O4) with (1 0 0) or (1 1 0) orientations and cerium dioxide or ceria (CeO2) were irradiated by 1.0 MeV and 2.5 MeV electrons in a high-fluence range. Point-defect production was studied by off-line UV-visible optical spectroscopy after irradiation. For spinel, regardless of both crystal orientation and electron energy, two characteristic broad bands centered at photon energies of 5.4 eV and 4.9 eV were assigned to F and F(+) centers (neutral and singly ionized oxygen vacancies), respectively, on the basis of available literature data. No clear differences in color-center formation were observed for the two crystal orientations. Using calculations from displacement cross sections by elastic collisions, these results are consistent with a very large threshold displacement energy (200 eV) for oxygen atoms at room temperature. A third very broad band centered at 3.7 eV might be attributed either to an oxygen hole center (V-type center) or an F2 dimer center (oxygen di-vacancy). The onset of recovery of these color centers took place at 200 °C with almost full bleaching at 600 °C. Activation energies (~0.3-0.4 eV) for defect recovery were deduced from the isochronal annealing data by using a first-order kinetics analysis. For ceria, a sub-band-gap absorption feature, which peaked at ~3.1 eV, was recorded for 2.5 MeV electron irradiation only. Assuming a ballistic process, we suggest that the latter defect might result from cerium atom displacement on the basis of computed cross sections. PMID:27319289

  19. Corrosion Problems in Absorption Chillers

    ERIC Educational Resources Information Center

    Stetson, Bruce

    1978-01-01

    Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

  20. Surface sensitivity of elastic peak electron spectroscopy

    NASA Astrophysics Data System (ADS)

    Jablonski, A.

    2016-08-01

    New theoretical model describing the sampling depth of elastic peak electron spectroscopy (EPES) has been proposed. Surface sensitivity of this technique can be generally identified with the maximum depth reached by trajectories of elastically backscattered electrons. A parameter called the penetration depth distribution function (PDDF) has been proposed for this description. Two further parameters are descendant from this definition: the mean penetration depth (MPD) and the information depth (ID). From the proposed theory, relatively simple analytical expressions describing the above parameters can be derived. Although the Monte Carlo simulations can be effectively used to estimate the sampling depth of EPES, this approach may require a considerable amount of computations. In contrast, the analytical model proposed here (AN) is very fast and provides the parameters PDDF, MPD and ID that very well compare with results of MC simulations. As follows from detailed comparisons performed for four elements (Al, Ni, Pd and Au), the AN model practically reproduced complicated emission angle dependences of the MPDs and the IDs, correctly indicating numerous maximum and minimum positions. In the energy range from 200 eV to 5 keV, the averaged percentage differences between MPDs obtained from the MC and the AN models were close to 4%. An important conclusion resulting from the present studies refers to the procedure of determination of the inelastic mean free path (IMFP) from EPES. Frequently, the analyzed sample is deposited as a thin overlayer on a smooth substrate. From an analysis of the presently obtained IDs, is follows that 99% of trajectories in analyzed experimental configurations reaches depth not exceeding 2.39 in units of IMFP. Thus, one can postulate that a safe minimum thickness of an overlayer should be larger than about 3 IMFPs. For example, the minimum thickness of an Al overlayer shoud be about 8 nm at 5000 eV.

  1. Research Opportunities at Storm Peak Laboratory

    NASA Astrophysics Data System (ADS)

    Hallar, A. G.; McCubbin, I. B.

    2006-12-01

    The Desert Research Institute (DRI) operates a high elevation facility, Storm Peak Laboratory (SPL), located on the west summit of Mt. Werner in the Park Range near Steamboat Springs, Colorado at an elevation of 3210 m MSL (Borys and Wetzel, 1997). SPL provides an ideal location for long-term research on the interactions of atmospheric aerosol and gas- phase chemistry with cloud and natural radiation environments. The ridge-top location produces almost daily transition from free tropospheric to boundary layer air which occurs near midday in both summer and winter seasons. Long-term observations at SPL document the role of orographically induced mixing and convection on vertical pollutant transport and dispersion. During winter, SPL is above cloud base 25% of the time, providing a unique capability for studying aerosol-cloud interactions (Borys and Wetzel, 1997). A comprehensive set of continuous aerosol measurements was initiated at SPL in 2002. SPL includes an office-type laboratory room for computer and instrumentation setup with outside air ports and cable access to the roof deck, a cold room for precipitation and cloud rime ice sample handling and ice crystal microphotography, a 150 m2 roof deck area for outside sampling equipment, a full kitchen and two bunk rooms with sleeping space for nine persons. The laboratory is currently well equipped for aerosol and cloud measurements. Particles are sampled from an insulated, 15 cm diameter manifold within approximately 1 m of its horizontal entry point through an outside wall. The 4 m high vertical section outside the building is capped with an inverted can to exclude large particles.

  2. Overview-absorption/Rankine solar cooling program

    NASA Astrophysics Data System (ADS)

    Wahlig, M.; Heitz, A.; Boyce, B.

    1980-03-01

    The tasks being performed in the absorption and Rankine program areas run the gamut from basic work on fluids to development of chillers and chiller components, to field and reliability testing of complete cooling systems. In the absorption program, there are six current and five essentially completed projects. In the Rankine program, there are five current projects directly supported by DOE, and three projects funded through and managed by NASA/MSFC (Manned Space Flight Center, Huntsville, Alabama). The basic features of these projects are discussed. The systems under development in five of these current projects were selected for field testing in the SOLERAS program, a joint US-Saudi Arabian enterprise. Some technical highlights of the program are presented.

  3. Polarized absorption spectra of (2,2) carbon nanotubes aligned in channels of an AEL crystal

    NASA Astrophysics Data System (ADS)

    Chen, Yanping; Zhai, Jianpang; Li, Irene Ling; Ruan, Shuangchen; Tang, Zikang

    2015-11-01

    We report polarized absorption spectra for the (2,2) tubes arrayed in the one-dimensional channels of an AlPO4-11 (AEL) single crystal. Strong polarization dependence is observed indicating a preferential optical dipole along the axis of carbon nanotubes. By correlating with the absorption spectra and First-principles local density function (LDA) calculation, the absorption peak at 2.95 eV is uniquely assigned to semiconducting type (2,2) tubes, and peaks at 2.67 and 2.40 eV are corresponding to metallic type (2,2) tubes.

  4. Tunable van Hove Singularities and Optical Absorption of Twisted Bilayer Graphene

    NASA Astrophysics Data System (ADS)

    Liang, Yufeng; Yang, Li

    2013-03-01

    We perform the first-principles GW-Bethe-Salpeter Equation (BSE) simulation to study the optical absorption spectra of isolated twisted bilayer graphene (TBLG). The twisting generates new van Hove singularities (VHS), and these VHSs and corresponding optical absorption peaks can be tuned in a wide range by the twist angle. Enhanced electron-electron and electron-hole interactions are shown to be important to understand both optical absorption peak positions and their lineshapes. With these many-electron effects included, our calculation satisfactorily explains recent experimental measurements.

  5. Acoustic Absorption Characteristics of People.

    ERIC Educational Resources Information Center

    Kingsbury, H. F.; Wallace, W. J.

    1968-01-01

    The acoustic absorption characteristics of informally dressed college students in typical classroom seating are shown to differ substantially from data for formally dressed audiences in upholstered seating. Absorption data, expressed as sabins per person or absorption coefficient per square foot, shows that there is considerable variation between…

  6. Forward ramp and Twin Peaks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    A lander petal and the forward ramp are featured in this image, taken by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. There are several prominent rocks, including Wedge at left; Shark, Half-Dome, and Pumpkin in the background; and Flat Top and Little Flat Top at center.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  7. ITALIAN PEAK AND ITALIAN PEAK MIDDLE ROADLESS AREAS, IDAHO AND MONTANA.

    USGS Publications Warehouse

    Skipp, Betty; Lambeth, Robert H.

    1984-01-01

    The Italian Peak and Italian Peak Middle Roadless Areas, in southwestern Montana and east-central Idaho, contain areas of probable mineral-resource potential based on combined geologic, geophysical, and geochemical studies and prospect examination. Small areas along the western, southern, and northeastern boundaries of the roadless areas have probable mineral resource potential for zinc, lead, silver, and uranium. An area of probable resource potential just east of and including a part of the Birch Creek mining district, may contain stratabound and fault-controlled silver and base metals, even though geochemical anomalies are low, and extensive prospecting has not identified any significant mineralization. The roadless areas are a part of the overthrust belt, and oil and gas possibilities must be assessed.

  8. D-peaks: a visual tool to display ChIP-seq peaks along the genome.

    PubMed

    Brohée, Sylvain; Bontempi, Gianluca

    2012-01-01

    ChIP-sequencing is a method of choice to localize the positions of protein binding sites on DNA on a whole genomic scale. The deciphering of the sequencing data produced by this novel technique is challenging and it is achieved by their rigorous interpretation using dedicated tools and adapted visualization programs. Here, we present a bioinformatics tool (D-peaks) that adds several possibilities (including, user-friendliness, high-quality, relative position with respect to the genomic features) to the well-known visualization browsers or databases already existing. D-peaks is directly available through its web interface http://rsat.ulb.ac.be/dpeaks/ as well as a command line tool. PMID:23132505

  9. Automatic quality assessment and peak identification of auditory brainstem responses with fitted parametric peaks.

    PubMed

    Valderrama, Joaquin T; de la Torre, Angel; Alvarez, Isaac; Segura, Jose Carlos; Thornton, A Roger D; Sainz, Manuel; Vargas, Jose Luis

    2014-05-01

    The recording of the auditory brainstem response (ABR) is used worldwide for hearing screening purposes. In this process, a precise estimation of the most relevant components is essential for an accurate interpretation of these signals. This evaluation is usually carried out subjectively by an audiologist. However, the use of automatic methods for this purpose is being encouraged nowadays in order to reduce human evaluation biases and ensure uniformity among test conditions, patients, and screening personnel. This article describes a new method that performs automatic quality assessment and identification of the peaks, the fitted parametric peaks (FPP). This method is based on the use of synthesized peaks that are adjusted to the ABR response. The FPP is validated, on one hand, by an analysis of amplitudes and latencies measured manually by an audiologist and automatically by the FPP method in ABR signals recorded at different stimulation rates; and on the other hand, contrasting the performance of the FPP method with the automatic evaluation techniques based on the correlation coefficient, FSP, and cross correlation with a predefined template waveform by comparing the automatic evaluations of the quality of these methods with subjective evaluations provided by five experienced evaluators on a set of ABR signals of different quality. The results of this study suggest (a) that the FPP method can be used to provide an accurate parameterization of the peaks in terms of amplitude, latency, and width, and (b) that the FPP remains as the method that best approaches the averaged subjective quality evaluation, as well as provides the best results in terms of sensitivity and specificity in ABR signals validation. The significance of these findings and the clinical value of the FPP method are highlighted on this paper. PMID:24661606

  10. Saturation analysis of ChIP-seq data for reproducible identification of binding peaks

    PubMed Central

    Hansen, Peter; Hecht, Jochen; Ibrahim, Daniel M.; Krannich, Alexander; Truss, Matthias; Robinson, Peter N.

    2015-01-01

    Chromatin immunoprecipitation coupled with next-generation sequencing (ChIP-seq) is a powerful technology to identify the genome-wide locations of transcription factors and other DNA binding proteins. Computational ChIP-seq peak calling infers the location of protein–DNA interactions based on various measures of enrichment of sequence reads. In this work, we introduce an algorithm, Q, that uses an assessment of the quadratic enrichment of reads to center candidate peaks followed by statistical analysis of saturation of candidate peaks by 5′ ends of reads. We show that our method not only is substantially faster than several competing methods but also demonstrates statistically significant advantages with respect to reproducibility of results and in its ability to identify peaks with reproducible binding site motifs. We show that Q has superior performance in the delineation of double RNAPII and H3K4me3 peaks surrounding transcription start sites related to a better ability to resolve individual peaks. The method is implemented in C+l+ and is freely available under an open source license. PMID:26163319

  11. Statistical Short-Range Guidance for Peak Wind Speed Forecasts at Edwards Air Force Base, CA

    NASA Technical Reports Server (NTRS)

    Dreher, Joseph G.; Crawford, Winifred; Lafosse, Richard; Hoeth, Brian; Burns, Kerry

    2009-01-01

    The peak winds near the surface are an important forecast element for space shuttle landings. As defined in the Flight Rules (FR), there are peak wind thresholds that cannot be exceeded in order to ensure the safety of the shuttle during landing operations. The National Weather Service Spaceflight Meteorology Group (SMG) is responsible for weather forecasts for all shuttle landings, and is required to issue surface average and 10-minute peak wind speed forecasts. They indicate peak winds are a challenging parameter to forecast. To alleviate the difficulty in making such wind forecasts, the Applied Meteorology Unit (AMU) developed a PC-based graphical user interface (GUI) for displaying peak wind climatology and probabilities of exceeding peak wind thresholds for the Shuttle Landing Facility (SLF) at Kennedy Space Center (KSC; Lambert 2003). However, the shuttle occasionally may land at Edwards Air Force Base (EAFB) in southern California when weather conditions at KSC in Florida are not acceptable, so SMG forecasters requested a similar tool be developed for EAFB.

  12. Peak-valley-peak pattern of histone modifications delineates active regulatory elements and their directionality.

    PubMed

    Pundhir, Sachin; Bagger, Frederik O; Lauridsen, Felicia B; Rapin, Nicolas; Porse, Bo T

    2016-05-19

    Formation of nucleosome free region (NFR) accompanied by specific histone modifications at flanking nucleosomes is an important prerequisite for enhancer and promoter activity. Due to this process, active regulatory elements often exhibit a distinct shape of histone signal in the form of a peak-valley-peak (PVP) pattern. However, different features of PVP patterns and their robustness in predicting active regulatory elements have never been systematically analyzed. Here, we present PARE, a novel computational method that systematically analyzes the H3K4me1 or H3K4me3 PVP patterns to predict NFRs. We show that NFRs predicted by H3K4me1 and me3 patterns are associated with active enhancers and promoters, respectively. Furthermore, asymmetry in the height of peaks flanking the central valley can predict the directionality of stable transcription at promoters. Using PARE on ChIP-seq histone modifications from four ENCODE cell lines and four hematopoietic differentiation stages, we identified several enhancers whose regulatory activity is stage specific and correlates positively with the expression of proximal genes in a particular stage. In conclusion, our results demonstrate that PVP patterns delineate both the histone modification landscape and the transcriptional activities governed by active enhancers and promoters, and therefore can be used for their prediction. PARE is freely available at http://servers.binf.ku.dk/pare. PMID:27095194

  13. Peak-valley-peak pattern of histone modifications delineates active regulatory elements and their directionality

    PubMed Central

    Pundhir, Sachin; Bagger, Frederik O.; Lauridsen, Felicia B.; Rapin, Nicolas; Porse, Bo T.

    2016-01-01

    Formation of nucleosome free region (NFR) accompanied by specific histone modifications at flanking nucleosomes is an important prerequisite for enhancer and promoter activity. Due to this process, active regulatory elements often exhibit a distinct shape of histone signal in the form of a peak-valley-peak (PVP) pattern. However, different features of PVP patterns and their robustness in predicting active regulatory elements have never been systematically analyzed. Here, we present PARE, a novel computational method that systematically analyzes the H3K4me1 or H3K4me3 PVP patterns to predict NFRs. We show that NFRs predicted by H3K4me1 and me3 patterns are associated with active enhancers and promoters, respectively. Furthermore, asymmetry in the height of peaks flanking the central valley can predict the directionality of stable transcription at promoters. Using PARE on ChIP-seq histone modifications from four ENCODE cell lines and four hematopoietic differentiation stages, we identified several enhancers whose regulatory activity is stage specific and correlates positively with the expression of proximal genes in a particular stage. In conclusion, our results demonstrate that PVP patterns delineate both the histone modification landscape and the transcriptional activities governed by active enhancers and promoters, and therefore can be used for their prediction. PARE is freely available at http://servers.binf.ku.dk/pare. PMID:27095194

  14. The accuracy of portable peak flow meters.

    PubMed Central

    Miller, M R; Dickinson, S A; Hitchings, D J

    1992-01-01

    BACKGROUND: The variability of peak expiratory flow (PEF) is now commonly used in the diagnosis and management of asthma. It is essential for PEF meters to have a linear response in order to obtain an unbiased measurement of PEF variability. As the accuracy and linearity of portable PEF meters have not been rigorously tested in recent years this aspect of their performance has been investigated. METHODS: The response of several portable PEF meters was tested with absolute standards of flow generated by a computer driven, servo controlled pump and their response was compared with that of a pneumotachograph. RESULTS: For each device tested the readings were highly repeatable to within the limits of accuracy with which the pointer position can be assessed by eye. The between instrument variation in reading for six identical devices expressed as a 95% confidence limit was, on average across the range of flows, +/- 8.5 l/min for the Mini-Wright, +/- 7.9 l/min for the Vitalograph, and +/- 6.4 l/min for the Ferraris. PEF meters based on the Wright meter all had similar error profiles with overreading of up to 80 l/min in the mid flow range from 300 to 500 l/min. This overreading was greatest for the Mini-Wright and Ferraris devices, and less so for the original Wright and Vitalograph meters. A Micro-Medical Turbine meter was accurate up to 400 l/min and then began to underread by up to 60 l/min at 720 l/min. For the low range devices the Vitalograph device was accurate to within 10 l/min up to 200 l/min, with the Mini-Wright overreading by up to 30 l/min above 150 l/min. CONCLUSION: Although the Mini-Wright, Ferraris, and Vitalograph meters gave remarkably repeatable results their error profiles for the full range meters will lead to important errors in recording PEF variability. This may lead to incorrect diagnosis and bias in implementing strategies of asthma treatment based on PEF measurement. PMID:1465746

  15. Absorption heat pumps

    NASA Astrophysics Data System (ADS)

    Huhtinen, M.; Heikkilae, M.; Andersson, R.

    1987-03-01

    The aim of the study was to analyze the technical and economic feasibility of absorption heat pumps in Finland. The work was done as a case study: the technical and economic analyses have been carried out for six different cases, where in each the suitable size and type of the heat pump plant and the auxiliary components and connections were specified. The study also detailed the costs concerning the procurement, installation and test runs of the machinery, as well as the savings in energy costs incurred by the introduction of the plant. Conclusions were drawn of the economic viability of the applications studied. The following cases were analyzed: heat recovery from flue gases and productin of district heat in plants using peat, natural gas, and municipal wastes as a fuel. Heat recovery in the pulp and paper industry for the upgrading of pressure of secondary steam and for the heating of white liquor and combustion and drying the air. Heat recovery in a peat-fulled heat and power plant from flue gases that have been used for the drying of peat. According to the study, the absorption heat pump suits best to the production of district heat, when the heat source is the primary energy is steam produced by the boiler. Included in the flue as condensing is the purification of flue gases. Accordingly, benefit is gained on two levels in thick applications. In heat and power plants the use of absorption heat pumps is less economical, due to the fact that the steam used by the pump reduces the production of electricity, which is rated clearly higher than heat.

  16. Rapid Levothyroxine Absorption Testing: A Case Series of Nonadherent Patients

    PubMed Central

    Balla, Mamtha; Jhingan, Ram M.; Rubin, Daniel J.

    2015-01-01

    Background: Nonadherence to levothyroxine therapy is one cause of persistent hypothyroidism. To distinguish nonadherence from malabsorption, a levothyroxine absorption test is required. Typically, this test measures the serum free thyroxine (FT4) response to 1000 mcg of oral levothyroxine over 4 to 24 hours. Published data indicate that serum levels of FT4 are at or near their peak 2 hours after levothyroxine ingestion. Objectives: We present the successful completion of 2-hour levothyroxine absorption testing in 3 patients as a retrospective case series. Patients and Methods: Serum levels of thyroid stimulating hormone (TSH), FT4, and free triiodothyronine (FT3) were drawn at 0, 60, and 120 minutes after 1000 mcg of oral levothyroxine. Results: In all 3 cases, baseline thyroid function indicated the patients had taken their prescribed doses of levothyroxine prior to the absorption test. Despite high baseline levels both FT3 and FT4 increased during each absorption test, providing more evidence of adequate levothyroxine absorption. Subsequently, patients achieved normal TSH levels on lower doses of levothyroxine. Conclusions: Levothyroxine absorption testing over 2 hours may offer a more rapid alternative to the commonly used longer protocols to rule out malabsorption. Scheduling a levothyroxine absorption test may induce some patients to start adhering to levothyroxine therapy. PMID:26633982

  17. Scattering with absorptive interaction

    NASA Astrophysics Data System (ADS)

    Cassing, W.; Stingl, M.; Weiguny, A.

    1982-07-01

    The S matrix for a wide class of complex and nonlocal potentials is studied, with special attention given to the motion of singularities in the complex k plane as a function of the imaginary coupling strength. Modifications of Levinson's theorem are obtained and discussed. Analytic approximations to the S matrix in the vicinity of narrow resonances are exhibited and compared to numerical results of resonating-group calculations. The problem of defining resonances in the case of complex interactions is discussed, making contact with the usual analysis of scattering in terms of Argand diagrams. NUCLEAR REACTIONS Scattering theory, S matrix for absorptive potentials.

  18. Ultraviolet absorption hygrometer

    DOEpatents

    Gersh, M.E.; Bien, F.; Bernstein, L.S.

    1986-12-09

    An ultraviolet absorption hygrometer is provided including a source of pulsed ultraviolet radiation for providing radiation in a first wavelength region where water absorbs significantly and in a second proximate wavelength region where water absorbs weakly. Ultraviolet radiation in the first and second regions which has been transmitted through a sample path of atmosphere is detected. The intensity of the radiation transmitted in each of the first and second regions is compared and from this comparison the amount of water in the sample path is determined. 5 figs.

  19. Ultraviolet absorption hygrometer

    DOEpatents

    Gersh, Michael E.; Bien, Fritz; Bernstein, Lawrence S.

    1986-01-01

    An ultraviolet absorption hygrometer is provided including a source of pulsed ultraviolet radiation for providing radiation in a first wavelength region where water absorbs significantly and in a second proximate wavelength region where water absorbs weakly. Ultraviolet radiation in the first and second regions which has been transmitted through a sample path of atmosphere is detected. The intensity of the radiation transmitted in each of the first and second regions is compared and from this comparison the amount of water in the sample path is determined.

  20. The effect of different particle sizes of polyethylene on the absorption of myrrh in mixtures

    NASA Astrophysics Data System (ADS)

    Xu, Lei; Li, Bin; Zuo, Jian; Zhang, Cunlin

    2015-08-01

    Terahertz radiation lies between far-infrared and microwave in electromagnetic spectrum with frequency from 0.1 to 10 THz. Absorption spectra of different mass ratio of the myrrh and polyethylene can be gained by Fourier transform infrared spectrometer in this paper. It is found that absorption spectra show a slight red-shift with the decrease of the mass ratio of myrrh and polyethylene. On the other hand, different particle sizes of polyethylene (PE) mixed with myrrh absorption spectra were measured. Due to the different sizes of polyethylene particles, there are some differences in the vibration peak intensity, peak position and peak numbers in the absorption spectra. The experimental results show that the scattering effect leads to this phenomenon.

  1. Thickness Optimization for Petroleum Coke in Microwave Dehydrating Based on the Analysis of Dynamic Absorption Efficiency

    NASA Astrophysics Data System (ADS)

    Shang, Xiaobiao; Chen, Junruo; Peng, Jinhui; Chen, Hua; Zhang, Weifeng; Guo, Shenghui; Chen, Guo

    2015-07-01

    An analytical approach is proposed to optimize the thickness of petroleum coke for achieving maximum microwave power absorption in microwave heating based on analysis of reflection loss (RL). The microwave RL of the petroleum coke layer was studied over the moisture content range of 1%-5% at 20 °C and the petroleum coke (10% moisture content) in the temperature range of 20 to 100 °C at 2.45 GHz. The results show that RL depends sensitively on the thickness of the petroleum coke and the absorption peak shifts towards a larger thickness as the moisture content of the petroleum coke increases. There exists a matching thickness corresponding to the maximum microwave absorption, the maximum absorbing peak decreases when the thickness of petroleum coke exceeds the matching thickness. We also show that the absorption peak is found to move towards a smaller thickness region with increasing petroleum coke temperature.

  2. IR absorption and Raman spectra of single crystals of stable germanium isotopes

    NASA Astrophysics Data System (ADS)

    Gavva, V. A.; Kotereva, T. V.; Lipskiy, V. A.; Nezhdanov, A. V.

    2016-02-01

    The Raman and IR absorption spectra of single crystals of germanium isotopes 72Ge, 73Ge, 74Ge, and 76Ge in the region of phonon absorption and interband electronic transitions are studied at room temperature. The dependence of the Raman peak position on the atomic mass has the form ν ~ M -1/2. The shifts of the phonon absorption peaks of individual isotopes with respect to germanium of natural isotopic composition natGe are determined. With increasing average atomic mass of germanium, these peaks shift to longer wavelengths. In the region of interband electronic transitions, the intrinsic absorption edge of 76Ge is observed to shift by 1 meV to higher energies with respect to Ge of natural isotopic composition. For isotopes with atomic masses close to that of natural germanium (72Ge,73Ge, 74Ge), we found no significant difference in the band gap width at room temperature.

  3. National Health Information Center

    MedlinePlus

    ... About ODPHP National Health Information Center National Health Information Center The National Health Information Center (NHIC) is ... of interest View the NHO calendar . Federal Health Information Centers and Clearinghouses Federal Health Information Centers and ...

  4. Terbium chloride--aluminum chloride vapor system. I. Absorption and excitation spectra

    SciTech Connect

    Caird, J.A.; Carnall, W.T.; Hessler, J.P.; Williams, C.W.

    1981-01-15

    The absorption spectrum of the vapor complex formed at elevated temperatures between TbCl/sub 3/ and AlCl/sub 3/ has been measured in the region 20 000--50 000 cm/sup -1/. Oscillator strengths of f--f absorption bands below 37 000 cm/sup -1/ were determined. Strong absorption due to opposite parity 4f/sup 7/5d states was observed in the 37 000 to 50 000 cm/sup -1/ region with a peak molar absorptivity of approximately 500 l/mol cm. Significant additional absorption attributed to a molecular complex was also observed in this region. By measuring the excitation spectrum it was found that the molecular absorption does not appear to lead to fluorescence of the /sup 5/D/sub 4/ state. In contrast, absorption by the 4f/sup 7/5d states does result in strong /sup 5/D/sub 4/ fluorescence.

  5. On the Theory of the Shift Linear Photovoltaic Effect in Semiconductors of Tetrahedral Symmetry Under Two-Photon Absorption

    NASA Astrophysics Data System (ADS)

    Rasulov, R. Ya.; Rasulov, V. R.; Eshboltaev, I.

    2016-05-01

    An occurrence of the current of the shift linear photovoltaic effect under two-photon absorption of light in semiconductors without a center of symmetry with a complex band structure is theoretically analyzed. The contributions both from the simultaneous absorption of two photons and successive absorption of two single photons to the photocurrent are taken into account.

  6. 7 CFR 457.163 - Nursery peak inventory endorsement.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... completed Peak Inventory Value Report is received by us. Coverage term. A period of time that begins on the... otherwise modify any other provision of your Nursery Crop Insurance Policy. 4. Peak Insurance Period... 7 Agriculture 6 2014-01-01 2014-01-01 false Nursery peak inventory endorsement. 457.163...

  7. 7 CFR 457.163 - Nursery peak inventory endorsement.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... completed Peak Inventory Value Report is received by us. Coverage term. A period of time that begins on the... otherwise modify any other provision of your Nursery Crop Insurance Policy. 4. Peak Insurance Period... 7 Agriculture 6 2012-01-01 2012-01-01 false Nursery peak inventory endorsement. 457.163...

  8. 7 CFR 457.163 - Nursery peak inventory endorsement.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... completed Peak Inventory Value Report is received by us. Coverage term. A period of time that begins on the... otherwise modify any other provision of your Nursery Crop Insurance Policy. 4. Peak Insurance Period... 7 Agriculture 6 2011-01-01 2011-01-01 false Nursery peak inventory endorsement. 457.163...

  9. Peak Shift Phenomenon: A Teaching Activity for Basic Learning Theory

    ERIC Educational Resources Information Center

    Keith, Kenneth D.

    2002-01-01

    Stimulus discrimination is a standard subject in undergraduate courses presenting basic principles of learning, and a particularly interesting aspect of discrimination is the peak shift phenomenon. Peak shift occurs in generalization tests following intradimensional discrimination training as a displacement of peak responding away from the S+ (a…

  10. Reward Value Effects on Timing in the Peak Procedure

    ERIC Educational Resources Information Center

    Galtress, Tiffany; Kirkpatrick, Kimberly

    2009-01-01

    Three experiments examined the effect of motivational variables on timing in the peak procedure. In Experiment 1, rats received a 60-s peak procedure that was coupled with long-term, between-phase changes in reinforcer magnitude. Increases in reinforcer magnitude produced a leftward shift in the peak that persisted for 20 sessions of training. In…

  11. 7 CFR 457.163 - Nursery peak inventory endorsement.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Nursery peak inventory endorsement. 457.163 Section... CORPORATION, DEPARTMENT OF AGRICULTURE COMMON CROP INSURANCE REGULATIONS § 457.163 Nursery peak inventory endorsement. Nursery Crop Insurance Peak Inventory Endorsement This endorsement is not continuous and must...

  12. Peak water limits to freshwater withdrawal and use

    PubMed Central

    Gleick, Peter H.; Palaniappan, Meena

    2010-01-01

    Freshwater resources are fundamental for maintaining human health, agricultural production, economic activity as well as critical ecosystem functions. As populations and economies grow, new constraints on water resources are appearing, raising questions about limits to water availability. Such resource questions are not new. The specter of “peak oil”—a peaking and then decline in oil production—has long been predicted and debated. We present here a detailed assessment and definition of three concepts of “peak water”: peak renewable water, peak nonrenewable water, and peak ecological water. These concepts can help hydrologists, water managers, policy makers, and the public understand and manage different water systems more effectively and sustainably. Peak renewable water applies where flow constraints limit total water availability over time. Peak nonrenewable water is observable in groundwater systems where production rates substantially exceed natural recharge rates and where overpumping or contamination leads to a peak of production followed by a decline, similar to more traditional peak-oil curves. Peak “ecological” water is defined as the point beyond which the total costs of ecological disruptions and damages exceed the total value provided by human use of that water. Despite uncertainties in quantifying many of these costs and benefits in consistent ways, more and more watersheds appear to have already passed the point of peak water. Applying these concepts can help shift the way freshwater resources are managed toward more productive, equitable, efficient, and sustainable use. PMID:20498082

  13. Determination of fixed water in rocks by infrared absorption

    USGS Publications Warehouse

    Breger, I.A.; Chandler, J.C.

    1969-01-01

    An infrared absorption technique has been developed for the quantitative determination of "fixed water" (H2O+) in rocks. Potassium bromide disks containing 2-mg samples are scanned in the 3-??m spectral region and absorption at 2.96 ??m is determined. Although the exact nature of this peak is not known, other than that it is caused by an interaction between the potassium bromide and hydroxyl groups and water, it can be used for quantitative analysis. Rock samples, other than those containing significant percentages of clay minerals, can be analyzed with a standard deviation of 0.26%.

  14. Transient radiation-induced absorption in laser materials

    NASA Astrophysics Data System (ADS)

    Brannon, Paul J.

    1994-06-01

    Transient radiation-induced absorption losses in laser materials have been measured using a pulsed nuclear reactor. Reactor pulse widths of 70 to 90 microsecond(s) and absorbed doses of 1 to 7.5 krad have been used. Transmission recovery times and peak absorption coefficients are given. Materials tested include LiNbO3, GSGG, silica substrates, and filter glasses used in the laser cavity. The filter glasses are tested at discrete wavelengths in the range 440 - 750 nm. Lithium niobate, MgO-doped LiNbO3, GSGG, and the silica substrates are tested at 1061 nm.

  15. Infrared electronic absorption in a single-component molecular metal.

    PubMed

    Kobayashi, Akiko; Sasa, Masaaki; Suzuki, Wakako; Fujiwara, Emiko; Tanaka, Hisashi; Tokumoto, Madoka; Okano, Yoshinori; Fujiwara, Hideki; Kobayashi, Hayao

    2004-01-21

    The infrared spectra of the crystal of transition metal complex molecules with extended-TTF ligands, Ni(tmdt)2, which is the first single-component molecular metal that has a stable metallic state even at low temperatures, exhibited an extremely low-energy electronic absorption around 2200 cm-1 (tmdt = trimethylenetetrathiafulvalenedithiolate). The systematic shift of the absorption peaks for molecules similar to Ni(tmdt)2, which range from metallic to semiconducting crystals, shows that the single-component molecular conductors are composed of molecules with unprecedentedly small HOMO-LUMO gaps. PMID:14719914

  16. Propagation, beam geometry, and detection distortions of peak shapes in two-dimensional Fourier transform spectra.

    PubMed

    Yetzbacher, Michael K; Belabas, Nadia; Kitney, Katherine A; Jonas, David M

    2007-01-28

    Using a solution of Maxwell's equations in the three-dimensional frequency domain, femtosecond two-dimensional Fourier transform (2DFT) spectra that include distortions due to phase matching, absorption, dispersion, and noncollinear excitation and detection of the signal are calculated for Bloch, Kubo, and Brownian oscillator relaxation models. For sample solutions longer than a wavelength, the resonant propagation distortions are larger than resonant local field distortions by a factor of approximately L/lambda, where L is the sample thickness and lambda is the optical wavelength. For the square boxcars geometry, the phase-matching distortion is usually least important, and depends on the dimensionless parameter, L sin(2)(beta)Deltaomega/(nc), where beta is the half angle between beams, n is the refractive index, c is the speed of light, and Deltaomega is the width of the spectrum. Directional filtering distortions depend on the dimensionless parameter, [(Deltaomega)w(0) sin(beta)/c](2), where w(0) is the beam waist at the focus. Qualitatively, the directional filter discriminates against off diagonal amplitude. Resonant absorption and dispersion can distort 2D spectra by 10% (20%) at a peak optical density of 0.1 (0.2). Complicated distortions of the 2DFT peak shape due to absorption and dispersion can be corrected to within 10% (15%) by simple operations that require knowledge only of the linear optical properties of the sample and the distorted two-dimensional spectrum measured at a peak optical density of up to 0.5 (1). PMID:17286491

  17. Propagation, beam geometry, and detection distortions of peak shapes in two-dimensional Fourier transform spectra

    NASA Astrophysics Data System (ADS)

    Yetzbacher, Michael K.; Belabas, Nadia; Kitney, Katherine A.; Jonas, David M.

    2007-01-01

    Using a solution of Maxwell's equations in the three-dimensional frequency domain, femtosecond two-dimensional Fourier transform (2DFT) spectra that include distortions due to phase matching, absorption, dispersion, and noncollinear excitation and detection of the signal are calculated for Bloch, Kubo, and Brownian oscillator relaxation models. For sample solutions longer than a wavelength, the resonant propagation distortions are larger than resonant local field distortions by a factor of ˜L/λ, where L is the sample thickness and λ is the optical wavelength. For the square boxcars geometry, the phase-matching distortion is usually least important, and depends on the dimensionless parameter, Lsin2(β )Δω/(nc), where β is the half angle between beams, n is the refractive index, c is the speed of light, and Δω is the width of the spectrum. Directional filtering distortions depend on the dimensionless parameter, [(Δω )w0sin(β)/c]2, where w0 is the beam waist at the focus. Qualitatively, the directional filter discriminates against off diagonal amplitude. Resonant absorption and dispersion can distort 2D spectra by 10% (20%) at a peak optical density of 0.1 (0.2). Complicated distortions of the 2DFT peak shape due to absorption and dispersion can be corrected to within 10% (15%) by simple operations that require knowledge only of the linear optical properties of the sample and the distorted two-dimensional spectrum measured at a peak optical density of up to 0.5 (1).

  18. Shape dependence of transmission, reflection, and absorption eigenvalue densities in disordered waveguides with dissipation

    NASA Astrophysics Data System (ADS)

    Yamilov, A.; Petrenko, S.; Sarma, R.; Cao, H.

    2016-03-01

    The universal bimodal distribution of transmission eigenvalues in lossless diffusive systems underpins such celebrated phenomena as universal conductance fluctuations, quantum shot noise in condensed matter physics, and enhanced transmission in optics and acoustics. Here, we show that in the presence of absorption, the density of the transmission eigenvalues depends on the confinement geometry of the scattering media. Furthermore, in an asymmetric waveguide, the densities of the reflection and absorption eigenvalues also depend on the side from which the waves are incident. With increasing absorption, the density of absorption eigenvalues transforms from a single-peak to a double-peak function. Our findings open an additional avenue for coherent control of wave transmission, reflection, and absorption in random media.

  19. Tunable diode laser measurements of CH3OOH absorption cross-sections near 1320 CM-1

    NASA Astrophysics Data System (ADS)

    Becker, K. H.; Brockmann, K. J.; Bechara, J.

    Infrared absorption spectra and absorption cross-sections in the C-H deformation band of CH3OOH near 1320 cm-1 have been measured with a tunable diode laser spectrometer. Methylhydroperoxide concentrations in a slowly flowing gas mixture were determined by UV absorption. Peak absorption cross-sections of the strongest lines observed were found to lie in the range (0.5 -1.5) × 10-18 cm² under near Doppler-limited conditions. The dependence of the peak absorption cross-sections on total air pressure in the range 2.5-90 torr was also investigated, and the possibility of CH3OOH atmospheric mixing ratio measurement with a tunable diode laser assessed.

  20. Color-Center Production and Formation in Electron-Irradiated Magnesium Aluminate Spinel and Ceria

    DOE PAGESBeta

    Costantini, Jean-Marc; Lelong, Gerald; Guillaumet, Maxime; Weber, William J.; Takaki, Seiya; Yasuda, Kazuhiro

    2016-06-20

    Single crystals of magnesium aluminate spinel (MgAl2O4) with (100) or (110) orientations and cerium dioxide or ceria (CeO2) were irradiated by 1.0-MeV and 2.5-MeV electrons in a high fluence range. Point-defect production was studied by off-line UV-visible optical spectroscopy after irradiation. For spinel, regardless of both crystal orientation and electron energy, two characteristic broad bands centered at photon energies of 5.4 eV and 4.9 eV were assigned to F and F+ centers (neutral and singly-ionized oxygen vacancies), respectively, on the basis of available literature data. No clear differences in colour-centre formation were observed for the two crystal orientations. Using calculationsmore » of displacement cross sections by elastic collisions, these results are consistent with a very large threshold displacement energy (200 eV) for oxygen atoms at RT. A third very broad band centered at 3.7 eV might be attributed either to an oxygen hole center (V-type center) or an F2 dimer center (oxygen di-vacancy). The onset of recovery of these color centers took place at 200°C with almost full bleaching at 600°C. Activation energies (~0.3-0.4 eV) for defect recovery were deduced from the isochronal annealing data by using a first-order kinetics analysis. For ceria, a sub band-gap absorption feature peaked at ~3.1 eV was recorded for 2.5-MeV electron irradiation only. Assuming a ballistic process, we suggest that the latter defect might result from cerium atom displacement on the basis of computed cross sections.« less

  1. Gas compression in lungs decreases peak expiratory flow depending on resistance of peak flowmeter.

    PubMed

    Pedersen, O F; Pedersen, T F; Miller, M R

    1997-11-01

    It has recently been shown (O. F. Pedersen T. R. Rasmussen, O. Omland, T. Sigsgaard, P. H. Quanjer. and M. R. Miller. Eur. Respir. J. 9: 828-833, 1996) that the added resistance of a mini-Wright peak flowmeter decreases peak expiratory flow (PEF) by approximately 8% compared with PEF measured by a pneumotachograph. To explore the reason for this, 10 healthy men (mean age 43 yr, range 33-58 yr) were examined in a body plethysmograph with facilities to measure mouth flow vs. expired volume as well as the change in thoracic gas volume (Vb) and alveolar pressure (PA). The subjects performed forced vital capacity maneuvers through orifices of different sizes and also a mini-Wright peak flowmeter. PEF with the meter and other added resistances were achieved when flow reached the perimeter of the flow-Vb curves. The mini-Wright PEF meter decreased PEF from 11.4 +/- 1.5 to 10.3 +/- 1.4 (SD) l/s (P < 0.001), PA increased from 6.7 +/- 1.9 to 9.3 +/- 2.7 kPa (P < 0.001), an increase equal to the pressure drop across the meter, and caused Vb at PEF to decrease by 0.24 +/- 0.09 liter (P < 0.001). We conclude that PEF obtained with an added resistance like a mini-Wright PEF meter is a wave-speed-determined maximal flow, but the added resistance causes gas compression because of increased PA at PEF. Therefore, Vb at PEF and, accordingly, PEF decrease. PMID:9375314

  2. Peak expiratory flow at increased barometric pressure: comparison of peak flow meters and volumetric spirometer.

    PubMed

    Thomas, P S; Ng, C; Bennett, M

    2000-01-01

    Increasing numbers of patients are receiving hyperbaric oxygen therapy as an intensive care treatment, some of whom have pre-existing airway obstruction. Spirometers are the ideal instruments for measuring airway obstruction, but peak flow meters are useful and versatile devices. The behaviour of both types of device was therefore studied in a hyperbaric unit under conditions of increased pressure. It is important to have a non-electrical indicator of airway obstruction, to minimize the fire risk in the hyperoxic environment. The hypothesis was tested that, assuming that dynamic resistance is unchanged, both the Wright's standard and mini-peak flow meters would over-read peak expiratory flow (PEF) under increased pressure when compared with a volumetric spirometer, as the latter is unaffected by air density. It was postulated that a correction factor could be derived so that PEF meters could be used in this setting. Seven normal subjects performed volume-dependent spirometry to derive PEF, and manoeuvres using both standard and mini PEF meters at sea level, under hyperbaric conditions at 303, 253 and 152 kPa (3, 2.5 and 1.5 atmospheres respectively; 1 atmosphere absolute=101.08 kPa), and again at sea level. There was a progressive and significant decline in PEF with increasing pressure as measured by the spirometer (69.46+/-0.8% baseline at 303 kPa compared with 101 kPa), while the PEF meters showed a progressive increase in their readings (an increase of 7.86+/-1.69% at 303 kPa with the mini PEF meter). Using these data points, a correction factor was derived which allows appropriate values to be calculated from the Wright's meter readings under these conditions. PMID:10600666

  3. Gamma radiation-induced blue shift of resonance peaks of Bragg gratings in pure silica fibres

    NASA Astrophysics Data System (ADS)

    Faustov, A. V.; Gusarov, A. I.; Mégret, P.; Wuilpart, M.; Kinet, D.; Zhukov, A. V.; Novikov, S. G.; Svetukhin, V. V.; Fotiadi, A. A.

    2016-02-01

    We report the first observation of a significant gamma radiation-induced blue shift of the reflection/transmission peak of fibre Bragg gratings inscribed into pure-silica core fibres via multiphoton absorption of femtosecond pulses. At a total dose of ~100 kGy, the shift is ~20 pm. The observed effect is attributable to the ionising radiation-induced decrease in the density of the silica glass when the rate of colour centre formation is slow. We present results of experimental measurements that provide the key parameters of the dynamics of the gratings for remote dosimetry and temperature sensing.

  4. Thulium-doped fiber chirped-pulse amplification system with 2 GW of peak power.

    PubMed

    Gaida, C; Gebhardt, M; Stutzki, F; Jauregui, C; Limpert, J; Tünnermann, A

    2016-09-01

    Thulium-doped fibers with ultra large mode-field areas offer new opportunities for the power scaling of mid-IR ultrashort-pulse laser sources. Here, we present a laser system delivering a pulse-peak power of 2 GW and a nearly transform-limited pulse duration of 200 fs in combination with 28.7 W of average power. This performance level has been achieved by optimizing the pulse shape, reducing the overlap with atmospheric absorption lines, and incorporating a climate chamber to reduce the humidity of the atmospheric environment. PMID:27607990

  5. Calcium absorption and vitamin D status in school age children

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing serum 25-hydroxyvitamin D (25-D) in adults may enhance calcium absorption (Ca-Abs). There are few similar pediatric data. We evaluated the relationship between 25-D and Ca-Abs by pooling data from 439 Ca-Abs measurements over a 15-yr period at our center in 251 healthy children 4.9 to 16....

  6. Memory Effect Manifested by a Boson Peak in Metallic Glass.

    PubMed

    Luo, P; Li, Y Z; Bai, H Y; Wen, P; Wang, W H

    2016-04-29

    We explore the correlation between a boson peak and structural relaxation in a typical metallic glass. Consistent with enthalpy recovery, a boson peak shows a memory effect in an aging-and-scan procedure. Single-step isothermal aging produces a monotonic decrease of enthalpy and boson peak intensity; for double-step isothermal aging, both enthalpy and boson peak intensity experience, coincidently, an incipient increase to a maximum and a subsequent decrease toward the equilibrium state. Our results indicate a direct link between slow structural relaxation and fast boson peak dynamics, which presents a profound understanding of the two dynamic behaviors in glass. PMID:27176528

  7. Memory Effect Manifested by a Boson Peak in Metallic Glass

    NASA Astrophysics Data System (ADS)

    Luo, P.; Li, Y. Z.; Bai, H. Y.; Wen, P.; Wang, W. H.

    2016-04-01

    We explore the correlation between a boson peak and structural relaxation in a typical metallic glass. Consistent with enthalpy recovery, a boson peak shows a memory effect in an aging-and-scan procedure. Single-step isothermal aging produces a monotonic decrease of enthalpy and boson peak intensity; for double-step isothermal aging, both enthalpy and boson peak intensity experience, coincidently, an incipient increase to a maximum and a subsequent decrease toward the equilibrium state. Our results indicate a direct link between slow structural relaxation and fast boson peak dynamics, which presents a profound understanding of the two dynamic behaviors in glass.

  8. Specific absorption spectra of hemoglobin at different PO2 levels: potential noninvasive method to detect PO2 in tissues

    NASA Astrophysics Data System (ADS)

    Liu, Peipei; Zhu, Zhirong; Zeng, Changchun; Nie, Guang

    2012-12-01

    Hemoglobin (Hb), as one of main components of blood, has a unique quaternary structure. Its release of oxygen is controlled by oxygen partial pressure (PO2). We investigate the specific spectroscopic changes in Hb under different PO2 levels to optimize clinical methods of measuring tissue PO2. The transmissivity of Hb under different PO2 levels is measured with a UV/Vis fiber optic spectrometer. Its plotted absorption spectral curve shows two high absorption peaks at 540 and 576 nm and an absorption valley at 560 nm when PO2 is higher than 100 mm Hg. The two high absorption peaks decrease gradually with a decrease in PO2, whereas the absorption valley at 560 nm increases. When PO2 decreases to approximately 0 mm Hg, the two high absorption peaks disappear completely, while the absorption valley has a hypochromic shift (8 to 10 nm) and forms a specific high absorption peak at approximately 550 nm. The same phenomena can be observed in visible reflectance spectra of finger-tip microcirculation. Specific changes in extinction coefficient and absorption spectra of Hb occur along with variations in PO2, which could be used to explain pathological changes caused by tissue hypoxia and for early detection of oxygen deficiency diseases in clinical monitoring.

  9. Study on peak shape fitting method in radon progeny measurement.

    PubMed

    Yang, Jinmin; Zhang, Lei; Abdumomin, Kadir; Tang, Yushi; Guo, Qiuju

    2015-11-01

    Alpha spectrum measurement is one of the most important methods to measure radon progeny concentration in environment. However, the accuracy of this method is affected by the peak tailing due to the energy losses of alpha particles. This article presents a peak shape fitting method that can overcome the peak tailing problem in most situations. On a typical measured alpha spectrum curve, consecutive peaks overlap even their energies are not close to each other, and it is difficult to calculate the exact count of each peak. The peak shape fitting method uses combination of Gaussian and exponential functions, which can depict features of those peaks, to fit the measured curve. It can provide net counts of each peak explicitly, which was used in the Kerr method of calculation procedure for radon progeny concentration measurement. The results show that the fitting curve fits well with the measured curve, and the influence of the peak tailing is reduced. The method was further validated by the agreement between radon equilibrium equivalent concentration based on this method and the measured values of some commercial radon monitors, such as EQF3220 and WLx. In addition, this method improves the accuracy of individual radon progeny concentration measurement. Especially for the (218)Po peak, after eliminating the peak tailing influence, the calculated result of (218)Po concentration has been reduced by 21 %. PMID:25920795

  10. Compositional Survey of Central Peaks in the South Pole-Aitken Basin from Moon Mineralogy Mapper (M3) data

    NASA Astrophysics Data System (ADS)

    Isaacson, P.; Nettles, J.; Boardman, J. W.; Petro, N. E.; Klima, R. L.; Taylor, L. A.; Pieters, C. M.; Cheek, L.; Clark, R. N.; Head, J. W.; Whitten, J.; Tompkins, S.; Besse, S.; Dhingra, D.; Moriarty, D.; Moon Mineralogy Mapper Team

    2010-12-01

    Orbital measurements allow the composition of planetary surfaces to be mapped globally, something not possible with returned samples. Optical instruments such as reflectance spectrometers, which are sensitive to the very uppermost surface (~1-2 mm depth), provide the highest spatial resolution of the various compositional remote sensing techniques. Major lunar rock-forming minerals exhibit diagnostic absorptions across visible to near-infrared (VNIR) wavelengths, and data returned by VNIR reflectance spectrometers can use these absorptions to map lunar mineralogy. However, on the Moon, much of the surface is dominated by mature lunar soils formed by the continual bombardment of the lunar surface over geologic time. This weathering process effectively weakens diagnostic mineral absorption features, complicating mineralogical analyses. Focused analyses of central peaks eliminate two of the drawbacks of remote VNIR reflectance spectroscopy. The steep slopes of central peaks inhibit the development of a thick regolith layer, meaning that central peaks are relatively optically immature and thus preserve the diagnostic spectral absorption features critical to compositional analyses. Furthermore, the crater formation process excavates materials from depth [e.g., Melosh, 1989, Cintala and Grieve, 1998], exposing materials that would otherwise be inaccessible to optical remote sensing. We are in the midst of a survey of lunar crater central peaks with Moon Mineralogy Mapper (M3) data, following the work of Tompkins and Pieters [1999], who used Clementine UVVIS multispectral data. We employ a band fitting procedure that gives estimates of the position, strength, and width of the mafic 1 μm absorption feature, which are used to evaluate the mineralogy of the central peaks. Within SPA are a number of craters of various sizes with well defined central peaks (e.g,. Bhabha, Fizeau, Finsen, Dryden) that presumably tap multiple depths across SPA, which itself excavated material

  11. Differential optoacoustic absorption detector

    NASA Technical Reports Server (NTRS)

    Shumate, M. S. (Inventor)

    1978-01-01

    A differential optoacoustic absorption detector employed two tapered cells in tandem or in parallel. When operated in tandem, two mirrors were used at one end remote from the source of the beam of light directed into one cell back through the other, and a lens to focus the light beam into the one cell at a principal focus half way between the reflecting mirror. Each cell was tapered to conform to the shape of the beam so that the volume of one was the same as for the other, and the volume of each received maximum illumination. The axes of the cells were placed as close to each other as possible in order to connect a differential pressure detector to the cells with connecting passages of minimum length. An alternative arrangement employed a beam splitter and two lenses to operate the cells in parallel.

  12. Cloud absorption radiometer

    NASA Technical Reports Server (NTRS)

    Strange, M. G.

    1988-01-01

    The Cloud Absorption Radiometer (CAR) was developed to measure spectrally how light is scattered by clouds and to determine the single scattering albedo, important to meteorology and climate studies, with unprecedented accuracy. This measurement is based on ratios of downwelling to upwelling radiation within clouds, and so is not strongly dependent upon absolute radiometric calibration of the instrument. The CAR has a 5-inch aperture and 1 degree IFOV, and spatially scans in a plane orthogonal to the flight vector from the zenith to nadir at 1.7 revolutions per second. Incoming light is measured in 13 spectral bands, using silicon, germanium, and indium-antimonide detectors. Data from each channel is digitally recorded in flight with 10-bit (0.1 percent) resolution. The instrument incorporates several novel features. These features are briefly detailed.

  13. Percutaneous absorption in preterm infants.

    PubMed

    West, D P; Halket, J M; Harvey, D R; Hadgraft, J; Solomon, L M; Harper, J I

    1987-11-01

    The skin of preterm infants varies considerably in its level of maturity. To understand skin absorption in premature infants better, we report a technique for the assessment of percutaneous absorption at various gestational and postnatal ages using stable, isotope-labeled (13C6) benzoic acid. Our results indicate that in the preterm infant, this method detects enhanced skin absorption in the first postnatal days, which declines over three weeks to that expected of a full-term infant. This approach also indicates an inverse relationship between gestational age and skin absorption, as well as postnatal age and skin absorption. The reported technique is a safe and noninvasive method using a model skin penetrant for the study of percutaneous absorption in preterm infants from which basic data may be derived to add to our understanding of skin barrier function. PMID:3422856

  14. KINEMATIC DISTANCE ASSIGNMENTS WITH H I ABSORPTION

    SciTech Connect

    Jones, Courtney; Dickey, John M.

    2012-07-01

    Using H I absorption spectra from the International Galactic Plane Survey, a new method is implemented to resolve the kinematic distance ambiguity for 75 H II regions with known systemic velocities from radio recombination lines. A further 40 kinematic distance determinations are made for H II region candidates without known systemic velocities through an investigation of the presence of H I absorption around the terminal velocity. New kinematic distance determinations can be used to further constrain spiral arm parameters and the location and extent of other structures in the Milky Way disk. H I absorption toward continuum sources beyond the solar circle is also investigated. Follow-up studies of H I at higher resolution than the 1' to 2' of existing Galactic Plane Surveys will provide kinematic distances to many more H II regions on the far side of the Galactic center. On the basis of the velocity channel summation technique developed in this paper, a much larger sample of H II regions will be analyzed in a future paper to remove the near-far distance ambiguity.

  15. Optical Absorption in Liquid Semiconductors

    NASA Astrophysics Data System (ADS)

    Bell, Florian Gene

    An infrared absorption cell has been developed which is suitable for high temperature liquids which have absorptions in the range .1-10('3) cm('-1). The cell is constructed by clamping a gasket between two flat optical windows. This unique design allows the use of any optical windows chemically compatible with the liquid. The long -wavelength limit of the measurements is therefore limited only by the choice of the optical windows. The thickness of the cell can easily be set during assembly, and can be varied from 50 (mu)m to .5 cm. Measurements of the optical absorption edge were performed on the liquid alloy Se(,1-x)Tl(,x) for x = 0, .001, .002, .003, .005, .007, and .009, from the melting point up to 475(DEGREES)C. The absorption was found to be exponential in the photon energy over the experimental range from 0.3 eV to 1.2 eV. The absorption increased linearly with concentration according to the empirical relation (alpha)(,T)(h(nu)) = (alpha)(,1) + (alpha)(,2)x, and the absorption (alpha)(,1) was interpreted as the absorption in the absence of T1. (alpha)(,1) also agreed with the measured absorption in 100% Se at corresponding temperatures and energies. The excess absorption defined by (DELTA)(alpha) = (alpha)(,T)(h(nu))-(alpha)(,1) was interpreted as the absorption associated with Tl and was found to be thermally activated with an activation energy E(,t) = 0.5 eV. The exponential edge is explained as absorption on atoms immersed in strong electric fields surrounding ions. The strong fields give rise to an absorption tail similar to the Franz-Keldysh effect. A simple calculation is performed which is based on the Dow-Redfield theory of absorption in an electric field with excitonic effects included. The excess absorption at low photon energies is proportional to the square of the concentration of ions, which are proposed to exist in the liquid according to the relation C(,i) (PROPORTIONAL) x(' 1/2)(.)e('-E)t('/kT), which is the origin of the thermal activation

  16. X-ray Absorption Spectroscopy

    SciTech Connect

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  17. Discrepancy between ambient annealing and H+ implantation in optical absorption of ZnO

    NASA Astrophysics Data System (ADS)

    Lv, Jinpeng; Li, Chundong

    2016-05-01

    The discrepancy between sub-bandgap absorption in ZnO induced by thermal annealing and H+ implantation is investigated in this study for the first time. Results indicate that nonreductive annealing-induced optical absorption is independent of annealing ambient, and can be assigned to VO, whereas the absorption centers caused by H+ implantation and H2 annealing are primarily associated with VO and ionized Zni.

  18. Quasi-static energy absorption of hollow microlattice structures

    SciTech Connect

    Liu, YL; Schaedler, TA; Jacobsen, AJ; Chen, X

    2014-12-01

    We present a comprehensive modeling and numerical study focusing on the energy quasi-static crushing behavior and energy absorption characteristics of hollow tube microlattice structures. The peak stress and effective plateau stress of the hollow microlattice structures are deduced for different geometrical parameters which gives volume and mass densities of energy absorption, D-v and D-m, scale with the relative density, (rho) over bar, as D-v similar to (rho) over bar (1) (5) and D-m similar to (rho) over bar (0 5), respectively, fitting very well to the experimental results of both 60 degrees inclined and 90 degrees predominately microlattices. Then the strategies for energy absorption enhancement are proposed for the engineering design of microlattice structures. By introducing a gradient in the thickness or radius of the lattice members, the buckle propagation can be modulated resulting in an increase in energy absorption density that can exceed 40%. Liquid filler is another approach to improve energy absorption by strengthening the microtruss via circumference expansion, and the gain may be over 100% in terms of volume density. Insight into the correlations between microlattice architecture and energy absorption performance combined with the high degree of architecture control paves the way for designing high performance microlattice structures for a range of impact and impulse mitigation applications for vehicles and structures. (C) 2014 Elsevier Ltd. All rights reserved.

  19. Seasonal changes in lead absorption in laboratory rats

    SciTech Connect

    Barton, J.C.; Huster, W.J.

    1987-08-01

    A retrospective study of the relationship of season to the absorption of radiolead in laboratory rats was performed using data representing 305 animals from 36 experiments over 6 calendar years. Male Wistar rats weighting 200 to 250 g were given 1 ..mu..g of radiolabeled lead in an aqueous solution, pH 4.0, in isolated small intestine, and absorption of the radiolead was quantified after a 4-hour interval using whole-body counting. Similar values of absorption occurred in the summer (June-August) and fall (September-November), but significantly lower values occurred in the winter (December-February). Harmonic analysis yielded an excellent approximation of the mean quarterly absorption data. The resulting cosine function had a period of 4.08 +/- 0.05 quarter-years with an amplitude of 7.32 +/- 1.06%; predicted peak absorption values fell precisely between summer and fall. The relationships of these observations to possible mechanisms of lead absorption and to summertime epidemics of lead poisoning in children are discussed.

  20. Optical absorption analysis and optimization of gold nanoshells.

    PubMed

    Tuersun, Paerhatijiang; Han, Xiang'e

    2013-02-20

    Gold nanoshells, consisting of a nanoscale dielectric core coated with an ultrathin gold shell, have wide biomedical applications due to their strong optical absorption properties. Gold nanoshells with high absorption efficiencies can help to improve these applications. We investigate the effects of the core material, surrounding medium, core radius, and shell thickness on the absorption spectra of gold nanoshells by using the light-scattering theory of a coated sphere. Our results show that the position and intensity of the absorption peak can be tuned over a wide range by manipulating the above-mentioned parameters. We also obtain the optimal absorption efficiencies and structures of hollow gold nanoshells and gold-coated SiO(2) nanoshells embedded in water at wavelengths of 800, 820, and 1064 nm. The results show that hollow gold nanoshells possess the maximum absorption efficiency (5.42) at a wavelength of 800 nm; the corresponding shell thickness and core radius are 4.8 and 38.9 nm, respectively. They can be used as the ideal photothermal conversation particles for biomedical applications. PMID:23435006

  1. Relationships between Electroencephalographic Spectral Peaks Across Frequency Bands

    PubMed Central

    van Albada, S. J.; Robinson, P. A.

    2013-01-01

    The degree to which electroencephalographic spectral peaks are independent, and the relationships between their frequencies have been debated. A novel fitting method was used to determine peak parameters in the range 2–35 Hz from a large sample of eyes-closed spectra, and their interrelationships were investigated. Findings were compared with a mean-field model of thalamocortical activity, which predicts near-harmonic relationships between peaks. The subject set consisted of 1424 healthy subjects from the Brain Resource International Database. Peaks in the theta range occurred on average near half the alpha peak frequency, while peaks in the beta range tended to occur near twice and three times the alpha peak frequency on an individual-subject basis. Moreover, for the majority of subjects, alpha peak frequencies were significantly positively correlated with frequencies of peaks in the theta and low and high beta ranges. Such a harmonic progression agrees semiquantitatively with theoretical predictions from the mean-field model. These findings indicate a common or analogous source for different rhythms, and help to define appropriate individual frequency bands for peak identification. PMID:23483663

  2. Removing Cool Cores and Central Metallicity Peaks in Galaxy Clusters with Powerful Active Galactic Nucleus Outbursts

    NASA Astrophysics Data System (ADS)

    Guo, Fulai; Mathews, William G.

    2010-07-01

    Recent X-ray observations of galaxy clusters suggest that cluster populations are bimodally distributed according to central gas entropy and are separated into two distinct classes: cool core (CC) and non-cool core (NCC) clusters. While it is widely accepted that active galactic nucleus (AGN) feedback plays a key role in offsetting radiative losses and maintaining many clusters in the CC state, the origin of NCC clusters is much less clear. At the same time, a handful of extremely powerful AGN outbursts have recently been detected in clusters, with a total energy ~1061-1062 erg. Using two-dimensional hydrodynamic simulations, we show that if a large fraction of this energy is deposited near the centers of CC clusters, which is likely common due to dense cores, these AGN outbursts can completely remove CCs, transforming them to NCC clusters. Our model also has interesting implications for cluster abundance profiles, which usually show a central peak in CC systems. Our calculations indicate that during the CC to NCC transformation, AGN outbursts efficiently mix metals in cluster central regions and may even remove central abundance peaks if they are not broad enough. For CC clusters with broad central abundance peaks, AGN outbursts decrease peak abundances, but cannot effectively destroy the peaks. Our model may simultaneously explain the contradictory (possibly bimodal) results of abundance profiles in NCC clusters, some of which are nearly flat, while others have strong central peaks similar to those in CC clusters. A statistical analysis of the sizes of central abundance peaks and their redshift evolution may shed interesting insights on the origin of both types of NCC clusters and the evolution history of thermodynamics and AGN activity in clusters.

  3. The relevance of food peak architecture in trophic interactions.

    PubMed

    Vatka, Emma; Orell, Markku; Rytkönen, Seppo

    2016-04-01

    Phenological shifts and associated changes in the temporal match between trophic levels have been a major focus of the study of ecological consequences of climate change. Previously, the food peak has been thought to respond as an entity to warming temperatures. However, food peak architecture, that is, timings and abundances of prey species and the level of synchrony between them, determines the timing and shape of the food peak. We demonstrate this with a case example of three passerine prey species and their predator. We explored temporal trends in the timing, height, width, and peakedness of prey availabilities and explained their variation with food peak architecture and ambient temperatures of prebreeding and breeding seasons. We found a temporal match between the predator's breeding schedule and food availability. Temporal trends in the timing of the food peak or in the synchrony between the prey species were not found. However, the food peak has become wider and more peaked over time. With more peaked food availabilities, predator's breeding success will depend more on the temporal match between its breeding schedule and the food peak, ultimately affecting the timing of breeding in the predator population. The height and width of the food peak depended on the abundances and breeding season lengths of individual prey species and their reciprocal synchronies. Peakednesses of separate prey species' availability distributions alone explained the peakedness of the food peak. Timing and quantity of food production were associated with temperatures of various time periods with variable relevance in different prey species. Alternating abundances of early and late breeding prey species caused high annual fluctuation in the timing of the food peak. Interestingly, the food peak may become later even when prey species' schedules are advanced. Climate warming can thus produce unexpected changes in the food availabilities, intervening in trophic interactions. PMID

  4. Influence of laser radiation on induced absorption spectra of pure quartz glass optical fibers

    NASA Astrophysics Data System (ADS)

    Dianov, Y. M.; Karpechev, V. N.; Korniyenko, L. S.; Rybaltovskiy, A. O.; Chernov, P. V.

    1986-01-01

    The influence of laser radiation on radiation color centers and their associated induced absorption in the spectra of irradiated glass optical fibers is investigated. The glass fiber specimens employed had 40 to 50 micron diameter cores made of day pure quartz glass. The optical fibers were 6 to 20 meters long, produced by chemical precipitation from the gaseous phase and clad with reflecting borosilicate glass. Spectral measurements of the induced absorption in the ultraviolet region were made using an FEU-71 photodetector and a sounding radiation source. The stimulated laser emission power in the cross section of the optical fiber was measured by a photodiode; the absorption spectra were recorded by the fragment method. Eight different types of color centers were isolated whose bands cover practically the entire observed absorption spectra. The connection found between color centers and a 340 nm absorption band, and color center with absorption in the infrared band, indicate that absorption in the ultraviolet band can have a significant influence on the amount of induced absorption in the infrared band.

  5. [Using 2-DCOS to identify the molecular spectrum peaks for the isomer in the multi-component mixture gases Fourier transform infrared analysis].

    PubMed

    Zhao, An-Xin; Tang, Xiao-Jun; Zhang, Zhong-Hua; Liu, Jun-Hua

    2014-10-01

    The generalized two-dimensional correlation spectroscopy and Fourier transform infrared were used to identify hydrocarbon isomers in the mixed gases for absorption spectra resolution enhancement. The Fourier transform infrared spectrum of n-butane and iso-butane and the two-dimensional correlation infrared spectrum of concentration perturbation were used for analysis as an example. The all band and the main absorption peak wavelengths of Fourier transform infrared spectrum for single component gas showed that the spectra are similar, and if they were mixed together, absorption peaks overlap and peak is difficult to identify. The synchronous and asynchronous spectrum of two-dimensional correlation spectrum can clearly identify the iso-butane and normal butane and their respective characteristic absorption peak intensity. Iso-butane has strong absorption characteristics spectrum lines at 2,893, 2,954 and 2,893 cm(-1), and n-butane at 2,895 and 2,965 cm(-1). The analysis result in this paper preliminary verified that the two-dimensional infrared correlation spectroscopy can be used for resolution enhancement in Fourier transform infrared spectrum quantitative analysis. PMID:25739197

  6. Enhanced Microwave Absorption Properties of Carbon Black/Silicone Rubber Coating by Frequency-Selective Surface

    NASA Astrophysics Data System (ADS)

    Yang, Zhaoning; Luo, Fa; Gao, Lu; Qing, Yuchang; Zhou, Wancheng; Zhu, Dongmei

    2016-06-01

    A square frequency-selective surface (FSS) design has been employed to improve the microwave absorption properties of carbon black/silicone rubber (CBSR) composite coating. The FSS is placed on the surface of the CBSR coating. The effects of FSS design parameters on the microwave absorption properties of the CBSR coating have been investigated, including the size and period of the FSS design, and the thickness and permittivity of the coating. Simulation results indicate that the absorption peak for the CBSR coating alone is related to its thickness and electromagnetic parameters, while the combination of the CBSR coating with a FSS can exhibit a new absorption peak in the reflection curve; the frequency of the new absorption peak is determined by the resonance of the square FSS design and tightly depends on the size of the squares, with larger squares in the FSS design leading to a lower frequency of the new absorption peak. The enhancement of the absorption performance depends on achievement of a new absorption peak using a suitable␣size and period of the FSS design. In addition, the FSS design has a stable␣frequency response for both transverse electromagnetic (TE) and transverse magnetic (TM) polarizations as the incident angle varies from 0° to 40°. The optimized results indicate that the bandwidth with reflection loss below -5 dB can encompass the whole frequency range from 8 GHz to 18 GHz for thickness of the CBSR coating of only 1.8 mm. The simulation results are confirmed by experiments.

  7. Polarization-adjustable dual-band absorption in GHz-band metamaterial, based-on no-smoking symbol

    NASA Astrophysics Data System (ADS)

    Yoo, Young Joon; Kim, Young Ju; Lee, YoungPak; Lee, Myung Whan; Lee, Tae Gyun; Kim, Min Woo; Park, Jae Hyun

    2015-11-01

    We propose three kinds of the perfect metamaterial absorbers based on the well-known no-smoking symbol, which can adjust the absorption according to the polarization of incident electromagnetic wave. By modifying no-smoking symbol, a resonance absorption peak at 6.75 GHz can be controlled. In addition, a split-ring structure and the no-smoking symbol also adjust the absorption. We also demonstrate the absorption mechanism for all the structures. These results can be used in controlling absorption by the electromagnetic-wave detector.

  8. A compact nonlinear fiber-based optical autocorrelation peak discriminator.

    PubMed

    Fok, M P; Deng, Y; Prucnal, P R

    2009-06-01

    We experimentally demonstrate a nonlinear fiber-based optical autocorrelation peak discriminator. The approach exploits four-wave mixing in a 37-cm highly-nonlinear bismuth-oxide fiber that provides a passive and compact means for rejecting cross-correlation peaks. The autocorrelation peak discriminator plays an important role in improving the detection of optical CDMA signals. Eye diagrams and bit-error rates are measured at different power ratios. Significant receiver sensitivity improvements are obtained and error-floors are removed. The experimental results show that the autocorrelation peak discriminator works well even when the amplitudes of individual cross-correlation peaks are higher than that of the autocorrelation peak. PMID:19506641

  9. Force Irregularity Following Maximal Effort: The After-Peak Reduction.

    PubMed

    Doucet, Barbara M; Mettler, Joni A; Griffin, Lisa; Spirduso, Waneen

    2016-08-01

    Irregularities in force output are present throughout human movement and can impair task performance. We investigated the presence of a large force discontinuity (after-peak reduction, APR) that appeared immediately following peak in maximal effort ramp contractions performed with the thumb adductor and ankle dorsiflexor muscles in 25 young adult participants (76% males, 24% females; M age 24.4 years, SD = 7.1). The after-peak reduction displayed similar parameters in both muscle groups with comparable drops in force during the after-peak reduction minima (thumb adductor: 27.5 ± 7.5% maximal voluntary contraction; ankle dorsiflexor: 25.8 ± 6.2% maximal voluntary contraction). A trend for the presence of fewer after-peak reductions with successive ramp trials was observed, suggesting a learning effect. Further investigation should explore underlying neural mechanisms contributing to the after-peak reduction. PMID:27502241

  10. Microwave absorption properties of Ni/(C, silicides) nanocapsules

    PubMed Central

    2012-01-01

    The microwave absorption properties of Ni/(C, silicides) nanocapsules prepared by an arc discharge method have been studied. The composition and the microstructure of the Ni/(C, silicides) nanocapsules were determined by means of X-ray diffraction, X-ray photoelectric spectroscopy, and transmission electron microscope observations. Silicides, in the forms of SiOx and SiC, mainly exist in the shells of the nanocapsules and result in a large amount of defects at the ‘core/shell’ interfaces as well as in the shells. The complex permittivity and microwave absorption properties of the Ni/(C, silicides) nanocapsules are improved by the doped silicides. Compared with those of Ni/C nanocapsules, the positions of maximum absorption peaks of the Ni/(C, silicides) nanocapsules exhibit large red shifts. An electric dipole model is proposed to explain this red shift phenomenon. PMID:22548846

  11. Tunable enhanced optical absorption of graphene using plasmonic perfect absorbers

    SciTech Connect

    Cai, Yijun; Zhu, Jinfeng; Liu, Qing Huo

    2015-01-26

    Enhancement and manipulation of light absorption in graphene is a significant issue for applications of graphene-based optoelectronic devices. In order to achieve this purpose in the visible region, we demonstrate a design of a graphene optical absorber inspired by metal-dielectric-metal metamaterial for perfect absorption of electromagnetic waves. The optical absorbance ratios of single and three atomic layer graphene are enhanced up to 37.5% and 64.8%, respectively. The graphene absorber shows polarization-dependence and tolerates a wide range of incident angles. Furthermore, the peak position and bandwidth of graphene absorption spectra are tunable in a wide wavelength range through a specific structural configuration. These results imply that graphene in combination with plasmonic perfect absorbers have a promising potential for developing advanced nanophotonic devices.

  12. [Spectral calibration for space-borne differential optical absorption spectrometer].

    PubMed

    Zhou, Hai-Jin; Liu, Wen-Qing; Si, Fu-Qi; Zhao, Min-Jie; Jiang, Yu; Xue, Hui

    2012-11-01

    Space-borne differential optical absorption spectrometer is used for remote sensing of atmospheric trace gas global distribution. This instrument acquires high accuracy UV/Vis radiation scattered or reflected by air or earth surface, and can monitor distribution and variation of trace gases based on differential optical absorption spectrum algorithm. Spectral calibration is the premise and base of quantification of remote sensing data of the instrument, and the precision of calibration directly decides the level of development and application of the instrument. Considering the characteristic of large field, wide wavelength range, high spatial and spectral resolution of the space-borne differential optical absorption spectrometer, a spectral calibration method is presented, a calibration device was built, the equation of spectral calibration was calculated through peak searching and regression analysis, and finally the full field spectral calibration of the instrument was realized. The precision of spectral calibration was verified with Fraunhofer lines of solar light. PMID:23387142

  13. Probing molecular chirality by coherent optical absorption spectra

    SciTech Connect

    Jia, W. Z.; Wei, L. F.

    2011-11-15

    We propose an approach to sensitively probe the chirality of molecules by measuring their coherent optical-absorption spectra. It is shown that quantum dynamics of the cyclic three-level chiral molecules driven by appropriately designed external fields is total-phase dependent. This will result in chirality-dependent absorption spectra for the probe field. As a consequence, the charality-dependent information in the spectra (such as the locations and relative heights of the characteristic absorption peaks) can be utilized to identify molecular chirality and determinate enantiomer excess (i.e., the percentages of different enantiomers). The feasibility of the proposal with chiral molecules confined in hollow-core photonic crystal fiber is also discussed.

  14. Intestinal folate absorption

    PubMed Central

    Strum, Williamson; Nixon, Peter F.; Bertino, Joseph B.; Binder, Henry J.

    1971-01-01

    Intestinal absorption of the monoglutamate form of the principal dietary and circulating folate compound, 5-methyltetrahydrofolic acid (5-MTHF), was studied in the rat utilizing a synthetic highly purified radiolabeled diastereoisomer. Chromatography confirmed that the compound was not altered after transfer from the mucosa to the serosa. Accumulation against a concentration gradient was not observed in duodenal, jejunal, or ileal segments at 5-MTHF concentration from 0.5 to 500 nmoles/liter. Unidirectional transmural flux determination also did not indicate a significant net flux. Mucosal to serosal transfer of 5-MTHF was similar in all segments of the intestine and increased in a linear fashion with increased initial mucosal concentrations. Further, no alteration in 5-MTHF transfer was found when studied in the presence of metabolic inhibitors or folate compounds. These results indicate that 5-MTHF is not absorbed by the rat small intestine by a carrier-mediated system and suggest that 5-MTHF transfer most likely represents diffusion. Images PMID:5564397

  15. Separation of overlapping vibrational peaks in terahertz spectra using two-dimensional correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Hoshina, Hiromichi; Ishii, Shinya; Otani, Chiko

    2014-07-01

    In this study, the terahertz (THz) absorption spectra of poly(3-hydroxybutyrate) (PHB) were measured during isothermal crystallization at 90-120 °C. The temporal changes in the absorption spectra were analyzed using two-dimensional correlation spectroscopy (2DCOS). In the asynchronous plot, cross peaks were observed around 2.4 THz, suggesting that two vibrational modes overlap in the raw spectrum. By comparing this to the peak at 2.9 THz corresponding to the stretching mode of the helical structure of PHB and the assignment obtained using polarization spectroscopy, we concluded that the high-frequency band could be attributed to the vibration of the helical structure and the low-frequency band to the vibration between the helical structures. The exact frequencies of the overlapping vibrational bands and their assignments provide a new means to inspect the thermal behavior of the intermolecular vibrational modes. The large red-shift of the interhelix vibrational mode suggests a large anharmonicity in the vibrational potential.

  16. Snoek peaks of carbon in Fe-Ni meteorites.

    NASA Astrophysics Data System (ADS)

    Weller, M.; Wert, C.

    1996-12-01

    Most Fe-Ni meteorites are a two phase mixture of fcc and bcc phases. The authors secured six samples of Fe contents from 95% to 85% all of which were thought to contain small amounts of carbon. They found no Snoek peaks in the as-received condition for any of the six. After being heated and cooled, three showed pronounced Snoek peaks, three showed no Snoek peaks.

  17. Gamma-ray peak shapes from cadmium zinc telluride detectors

    SciTech Connect

    Namboodiri, M.N.; Lavietes, A.D.; McQuaid, J.H.

    1996-09-01

    We report the results of a study of the peak shapes in the gamma spectra measured using several 5 x 5 x 5 mm{sup 3} cadmium zinc telluride (CZT) detectors. A simple parameterization involving a Gaussian and an exponential low energy tail describes the peak shapes sell. We present the variation of the parameters with gamma energy. This type of information is very useful in the analysis of complex gamma spectra consisting of many peaks.

  18. Peak experiences of psilocybin users and non-users.

    PubMed

    Cummins, Christina; Lyke, Jennifer

    2013-01-01

    Maslow (1970) defined peak experiences as the most wonderful experiences of a person's life, which may include a sense of awe, well-being, or transcendence. Furthermore, recent research has suggested that psilocybin can produce experiences subjectively rated as uniquely meaningful and significant (Griffiths et al. 2006). It is therefore possible that psilocybin may facilitate or change the nature of peak experiences in users compared to non-users. This study was designed to compare the peak experiences of psilocybin users and non-users, to evaluate the frequency of peak experiences while under the influence of psilocybin, and to assess the perceived degree of alteration of consciousness during these experiences. Participants were recruited through convenience and snowball sampling from undergraduate classes and at a musical event. Participants were divided into three groups, those who reported a peak experience while under the influence of psilocybin (psilocybin peak experience: PPE), participants who had used psilocybin but reported their peak experiences did not occur while they were under the influence of psilocybin (non-psilocybin peak experience: NPPE), and participants who had never used psilocybin (non-user: NU). A total of 101 participants were asked to think about their peak experiences and complete a measure evaluating the degree of alteration of consciousness during that experience. Results indicated that 47% of psilocybin users reported their peak experience occurred while using psilocybin. In addition, there were significant differences among the three groups on all dimensions of alteration of consciousness. Future research is necessary to identify factors that influence the peak experiences of psilocybin users in naturalistic settings and contribute to the different characteristics of peak experiences of psilocybin users and non-users. PMID:23909006

  19. QSOs and Absorption-Line Systems surrounding the Hubble Deep Field

    SciTech Connect

    Vanden Berk, Daniel E.; Stoughton, Chris; Crotts, Arlin P. S.; Tytler, David; Kirkman, David

    2000-06-01

    We have imaged a 45' x 45' area centered on the Hubble Deep Field (HDF) in UBVRI passbands, down to the limiting magnitudes of approximately 21.5, 22.5, 22.2, 22.2, and 21.2, respectively. The principal goals of the survey are to identify quasi-stellar objects (QSOs) and to map structure traced by luminous galaxies and QSO absorption line systems in a wide volume containing the HDF. The area surveyed is 400 times as large as that of the HDF, and 40 times as large as that of the HDF Flanking Fields. We have selected QSO candidates from color space and identified four QSOs and two narrow emission line galaxies not yet discovered, bringing the total number of known QSOs in the area to 19. The bright z=1.305 QSO only 12' away from the HDF raises the northern HDF to nearly the same status as the southern Hubble Deep Field, which was selected to be proximate to a bright QSO. About half of the QSO candidates remain for spectroscopic verification. Absorption-line spectroscopy has been obtained for three bright QSOs in the field, using the 10 m Keck, 3.5 m ARC, and 2.4 m MDM telescopes. Five heavy-element absorption line systems have been identified, four of which overlap the well-explored redshift range covered by deep galaxy redshift surveys toward the HDF. The two absorbers at z=0.5565 and z=0.5621 occur at the same redshift as the secondmost populated redshift peak in the galaxy distribution, but each is more than 7 h-1 Mpc (comoving, {omega}{sub m} =1, {omega}{sub {lambda}} =0) away from the HDF line of sight in the transverse dimension. This supports more indirect evidence that the galaxy redshift peaks are contained within large sheetlike structures that traverse the HDF and may be precursors to large-scale ''pancake'' structures seen in the present-day galaxy distribution. (c) 2000 The American Astronomical Society.

  20. Donor impurity-related linear and nonlinear intraband optical absorption coefficients in quantum ring: effects of applied electric field and hydrostatic pressure

    PubMed Central

    2012-01-01

    The linear and nonlinear intraband optical absorption coefficients in GaAs three-dimensional single quantum rings are investigated. Taking into account the combined effects of hydrostatic pressure and electric field, applied along the growth direction of the heterostructure, the energies of the ground and first excited states of a donor impurity have been found using the effective mass approximation and a variational method. The energies of these states are examined as functions of the dimensions of the structure, electric field, and hydrostatic pressure. We have also investigated the dependencies of the linear, nonlinear, and total optical absorption coefficients as a function of incident photon energy for several configurations of the system. It is found that the variation of distinct sizes of the structure leads to either a redshift and/or a blueshift of the resonant peaks of the intraband optical spectrum. In addition, we have found that the application of an electric field leads to a redshift, whereas the influence of hydrostatic pressure leads to a blueshift (in the case of on-ring-center donor impurity position) of the resonant peaks of the intraband optical spectrum. PMID:23021497

  1. Donor impurity-related linear and nonlinear intraband optical absorption coefficients in quantum ring: effects of applied electric field and hydrostatic pressure.

    PubMed

    Barseghyan, Manuk G; Restrepo, Ricardo L; Mora-Ramos, Miguel E; Kirakosyan, Albert A; Duque, Carlos A

    2012-01-01

    : The linear and nonlinear intraband optical absorption coefficients in GaAs three-dimensional single quantum rings are investigated. Taking into account the combined effects of hydrostatic pressure and electric field, applied along the growth direction of the heterostructure, the energies of the ground and first excited states of a donor impurity have been found using the effective mass approximation and a variational method. The energies of these states are examined as functions of the dimensions of the structure, electric field, and hydrostatic pressure. We have also investigated the dependencies of the linear, nonlinear, and total optical absorption coefficients as a function of incident photon energy for several configurations of the system. It is found that the variation of distinct sizes of the structure leads to either a redshift and/or a blueshift of the resonant peaks of the intraband optical spectrum. In addition, we have found that the application of an electric field leads to a redshift, whereas the influence of hydrostatic pressure leads to a blueshift (in the case of on-ring-center donor impurity position) of the resonant peaks of the intraband optical spectrum. PMID:23021497

  2. Zener Relaxation Peak in an Fe-Cr-Al Alloy

    NASA Astrophysics Data System (ADS)

    Zhou, Zheng-Cun; Cheng, He-Fa; Gong, Chen-Li; Wei, Jian-Ning; Han, Fu-Sheng

    2002-11-01

    We have studied the temperature spectra of internal friction and relative dynamic modulus of the Fe-(25 wt%)Cr-(5 wt%)Al alloy with different grain sizes. It is found that a peak appears in the internal friction versus temperature plot at about 550°C. The peak is of a stable relaxation and is reversible, which occurs not only during heating but also during cooling. Its activation energy is 2.5 (+/- 0.15) eV in terms of the Arrhenius relation. In addition, the peak is not obvious in specimens with a smaller grain size. It is suggested that the peak originates from Zener relaxation.

  3. Improved Peak Cancellation for PAPR Reduction in OFDM Systems

    NASA Astrophysics Data System (ADS)

    Dan, Lilin; Xiao, Yue; Ni, Wei; Li, Shaoqian

    This letter presents an improved peak cancellation (PC) scheme for peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems. The main idea is based on a serial peak cancellation (SPC) mode for alleviating the peak regrowth of the conventional schemes. Based on the SPC mode, two particular algorithms are developed with different tradeoff between PAPR and computational complexity. Simulation shows that the proposed scheme has a better tradeoff among PAPR, complexity and signal distortion than the conventional schemes.

  4. Neutron-induced peaks in Ge detectors from evaporation neutrons

    NASA Astrophysics Data System (ADS)

    Gete, E.; Measday, D. F.; Moftah, B. A.; Saliba, M. A.; Stocki, T. J.

    1997-02-01

    We have studied the peak shapes at 596 and 691 keV resulting from fast neutron interactions inside germanium detectors. We have used neutrons from a 252Cf source, as well as from the 28Si(μ -, nv), and 209Bi(π -, xn) reactions to compare the peaks and to check for a dependence of peak shape on the incoming neutron energy. In our investigation, no difference between these three measurements has been observed. In a comparison of these peak shapes with other studies, we found similar results to ours except for those measurements using monoenergetic neutrons in which a significant variation with neutron energy has been observed.

  5. Peak Doctor v 1.0.0 Labview Version

    SciTech Connect

    Garner, Scott

    2014-05-29

    PeakDoctor software works interactively with its user to analyze raw gamma-ray spectroscopic data. The goal of the software is to produce a list of energies and areas of all of the peaks in the spectrum, as accurately as possible. It starts by performing an energy calibration, creating a function that describes how energy can be related to channel number. Next, the software determines which channels in the raw histogram are in the Compton continuum and which channels are parts of a peak. Then the software fits the Compton continuum with cubic polynomials. The last step is to fit all of the peaks with Gaussian functions, thus producing the list.

  6. Solar Absorption in Cloudy Atmospheres

    NASA Technical Reports Server (NTRS)

    Harshvardhan; Ridgway, William; Ramaswamy, V.; Freidenreich, S. M.; Batey, Michael

    1996-01-01

    The theoretical computations used to compute spectral absorption of solar radiation are discussed. Radiative properties relevant to the cloud absorption problem are presented and placed in the context of radiative forcing. Implications for future measuring programs and the effect of horizontal inhomogeneities are discussed.

  7. Atlas of Infrared Absorption Lines

    NASA Technical Reports Server (NTRS)

    Park, J. H.

    1977-01-01

    This atlas of infrared absorption line contains absorption line parameters (line strength vs. wavenumber) from 500 to 7000 cm(exp-1) for 15 gases: H2O, CO2, O3, N2O, CO, CH4, O2, SO2, NO, NO2, NH3, HCl, HF, HNO3 and CH3Cl.

  8. Hot tube atomic absorption spectrochemistry.

    PubMed

    Woodriff, R; Stone, R W

    1968-07-01

    A small, commercially available atomic absorption instrument is used with a heated graphite tube for the atomic absorption analysis of liquid and solid silver samples. Operating conditions of the furnace are described and a sensitivity of about 5 ng of silver is reported. PMID:20068797

  9. Subgap Absorption in Conjugated Polymers

    DOE R&D Accomplishments Database

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of < 10{sup {minus}5}, Photothermal Deflection Spectroscopy (PDS) is ideal for determining the absorption coefficients of thin films of transparent'' materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination.

  10. Atmospheric absorption of sound - Update

    NASA Technical Reports Server (NTRS)

    Bass, H. E.; Sutherland, L. C.; Zuckerwar, A. J.

    1990-01-01

    Best current expressions for the vibrational relaxation times of oxygen and nitrogen in the atmosphere are used to compute total absorption. The resulting graphs of total absorption as a function of frequency for different humidities should be used in lieu of the graph published earlier by Evans et al (1972).

  11. Distinct difference in absorption pattern in pigs of betaine provided as a supplement or present naturally in cereal dietary fiber.

    PubMed

    Hedemann, Mette Skou; Theil, Peter Kappel; Lærke, Helle Nygaard; Bach Knudsen, Knud Erik

    2015-03-18

    The net absorption of betaine and choline was determined for 4 h after the first meal of the day in three experiments with porto-arterial catheterized pigs in which betaine was added as a supplement to a low-betaine diet (n=4 pigs) and compared to the net absorption of betaine and choline from high-fiber breads differing in amount and source of dietary fiber (two experiments, n=6 pigs each). Plasma betaine peaked after 30 min when betaine was fed as a supplement, whereas it peaked after 120-180 min when high-fiber breads were fed. Plasma betaine showed no diet×time interaction after feeding with high-fiber breads, indicating that the absorption kinetic did not differ between fiber sources. The net absorption of choline was not affected by the experimental diets. In conclusion, betaine in cereal sources has to be liberated from the matrix prior to absorption, causing delayed absorption. PMID:25716171

  12. Vanishing absorption and blueshifted emission in FeLoBAL quasars

    NASA Astrophysics Data System (ADS)

    Rafiee, Alireza; Pirkola, Patrik; Hall, Patrick B.; Galati, Natalee; Rogerson, Jesse; Ameri, Abtin

    2016-07-01

    We study the dramatic decrease in iron absorption strength in the iron low-ionization broad absorption line quasar SDSS J084133.15+200525.8. We report on the continued weakening of absorption in the prototype of this class of variable broad absorption line quasar, FBQS J140806.2+305448. We also report a third example of this class, SDSS J123103.70+392903.6; unlike the other two examples, it has undergone an increase in observed continuum brightness (at 3000 Å rest frame) as well as a decrease in iron absorption strength. These changes could be caused by absorber transverse motion or by ionization variability. We note that the Mg II and UV Fe II lines in several FeLoBAL quasars are blueshifted by thousands of km s-1 relative to the H β emission line peak. We suggest that such emission arises in the outflowing winds normally seen only in absorption.

  13. Ultrasensitive optical absorption in graphene based on bound states in the continuum

    PubMed Central

    Zhang, Mingda; Zhang, Xiangdong

    2015-01-01

    We have designed a sphere-graphene-slab structure so that the electromagnetic wave can be well confined in the graphene due to the formation of a bound state in a continuum (BIC) of radiation modes. Based on such a bound state, we have realized strong optical absorption in the monolayer graphene. Such a strong optical absorption exhibits many advantages. It is ultrasensitive to the wavelength because the Q factor of the absorption peak can be more than 2000. By taking suitable BICs, the selective absorption for S and P waves has not only been realized, but also all-angle absorption for the S and P waves at the same time has been demonstrated. We have also found that ultrasensitive strong absorptions can appear at any wavelength from mid-infrared to far-infrared band. These phenomena are very beneficial to biosensing, perfect filters and waveguides. PMID:25652437

  14. Absorption spectra of irradiated XRCT radiochromic film

    NASA Astrophysics Data System (ADS)

    Butson, Martin J.; Cheung, Tsang; Yu, Peter K. N.

    2006-06-01

    Gafchromic XRCT radiochromic film is a self-developing high sensitivity radiochromic film product which can be used for assessment of delivered radiation doses which could match applications such as computed tomography (CT) dosimetry. The film automatically changes colour upon irradiation changing from a yellow to green/brown colour. The absorption spectra of Gafchromic XRCT radiochromic film as measured with reflectance spectrophotometry have been investigated to analyse the dosimetry characteristics of the film. Results show two main absorption peaks produced from irradiation located at 636 nm and 585 nm. This is similar to EBT Gafchromic film. A high level of sensitivity is found for this film with a 1 cGy applied dose producing an approximate net optical density change of 0.3 at 636 nm. This high sensitivity combined with its relatively energy independent nature around the 100 kVp to 150 kVp x-ray energy range provides a unique enhancement in dosimetric measurement capabilities over currently available dosimetry films for CT applications.

  15. Millimeter wave absorption spectra of biological samples

    SciTech Connect

    Gandhi, O.P.; Hagmann, M.J.; Hill, D.W.; Partlow, L.M.; Bush, L.

    1980-01-01

    A solid-state computer-controlled system has been used to make swept-frequency measurements of absorption of biological specimens from 26.5 to 90.0 GHz. A wide range of samples was used, including solutions of DNA and RNA, and suspensions of BHK-21/C13 cells, Candida albicans, C krusei, and Escherichia coli. Sharp spectra reported by other workers were not observed. The strong absorbance of water (10--30 dB/mm) caused the absorbance of all aqueous preparations that we examined to have a water-like dependence on frequency. Reduction of incident power (to below 1.0 microW), elimination of modulation, and control of temperature to assure cell viability were not found to significantly alter the water-dominated absorbance. Frozen samples of BHK-21/C13 cells tested at dry ice and liquid nitrogen temperatures were found to have average insertion loss reduced to 0.2 dB/cm but still showed no reproducible peaks that could be attributed to absorption spectra. It is concluded that the special resonances reported by others are likely to be in error.

  16. Effects of thermal motion on electromagnetically induced absorption

    SciTech Connect

    Tilchin, E.; Wilson-Gordon, A. D.; Firstenberg, O.

    2011-05-15

    We describe the effect of thermal motion and buffer-gas collisions on a four-level closed N system interacting with strong pump(s) and a weak probe. This is the simplest system that experiences electromagnetically induced absorption (EIA) due to transfer of coherence via spontaneous emission from the excited state to the ground state. We investigate the influence of Doppler broadening, velocity-changing collisions (VCC), and phase-changing collisions (PCC) with a buffer gas on the EIA spectrum of optically active atoms. In addition to exact expressions, we present an approximate solution for the probe absorption spectrum, which provides physical insight into the behavior of the EIA peak due to VCC, PCC, and the wave-vector difference between the pump and probe beams. VCC are shown to produce a wide pedestal at the base of the EIA peak, which is scarcely affected by the pump-probe angular deviation, whereas the sharp central EIA peak becomes weaker and broader due to the residual Doppler-Dicke effect. Using diffusionlike equations for the atomic coherences and populations, we construct a spatial-frequency filter for a spatially structured probe beam and show that Ramsey narrowing of the EIA peak is obtained for beams of finite width.

  17. A Report on Educational Partnerships Supporting the Galileo Centre at Banded Peak School in Rocky View School Division.

    ERIC Educational Resources Information Center

    Jacobsen, D. Michele; Gladstone, Brenda

    This report describes the school-business partnerships that have contributed to the success of the Galileo Center at Banded Peak School in Bragg Creek, Alberta, in its first full year of operation. It summarizes partnership activities and initiatives that have been implemented in the school and suggests directions for future linkages. The need for…

  18. Peak flowmeter resistance decreases peak expiratory flow in subjects with COPD.

    PubMed

    Miller, M R; Pedersen, O F

    2000-07-01

    Previous studies have shown that the added resistance of a mini-Wright peak expiratory flow (PEF) meter reduced PEF by approximately 8% in normal subjects because of gas compression reducing thoracic gas volume at PEF and thus driving elastic recoil pressure. We undertook a body plethysmographic study in 15 patients with chronic obstructive pulmonary disease (COPD), age 65.9 +/- 6.3 yr (mean +/- SD, range 53-75 yr), to examine whether their recorded PEF was also limited by the added resistance of a PEF meter. The PEF meter increased alveolar pressure at PEF (Ppeak) from 3.7 +/- 1.4 to 4.7 +/- 1.5 kPa (P = 0.01), and PEF was reduced from 3.6 +/- 1.3 l/s to 3.2 +/- 0.9 l/s (P = 0.01). The influence of flow limitation on PEF and Ppeak was evaluated by a simple four-parameter model based on the wave-speed concept. We conclude that added external resistance in patients with COPD reduced PEF by the same mechanisms as in healthy subjects. Furthermore, the much lower Ppeak in COPD patients is a consequence of more severe flow limitation than in healthy subjects and not of deficient muscle strength. PMID:10904063

  19. Atomistic Simulation of Carbon Nanotube Ropes and Hydrogen Absorption

    NASA Astrophysics Data System (ADS)

    Li, Ju; Yip, Sidney; Fujiwara, Joshua

    2001-06-01

    Atomistic Simulation of Carbon Nanotube Ropes and Hydrogen Absorption Ju Li, Sidney Yip, Massachusetts Institute of Technology, Department of Nuclear Engineering, Cambridge, MA 02139; Joshua Fujiwara, Honda R&D Co., Ltd., Wako Research Center, JAPAN. Using Brenner type Reactive Empirical Bond Order (REBO) interatomic potentials, we perform atomistic simulations to calculate the optimized structures, tensile and bending strengths, and thermal conductivities of both straight and twisted single-walled nanotube ropes (bundles) where results from direct simulation are checked against those from the Green-Kubo linear response theory. Preliminary calculations are performed to study hydrogen absorption by SWNTs at room temperature and 77K.

  20. WEAK-LENSING PEAK FINDING: ESTIMATORS, FILTERS, AND BIASES

    SciTech Connect

    Schmidt, Fabian

    2011-07-10

    Large catalogs of shear-selected peaks have recently become a reality. In order to properly interpret the abundance and properties of these peaks, it is necessary to take into account the effects of the clustering of source galaxies, among themselves and with the lens. In addition, the preferred selection of magnified galaxies in a flux- and size-limited sample leads to fluctuations in the apparent source density that correlate with the lensing field. In this paper, we investigate these issues for two different choices of shear estimators that are commonly in use today: globally normalized and locally normalized estimators. While in principle equivalent, in practice these estimators respond differently to systematic effects such as magnification and cluster member dilution. Furthermore, we find that the answer to the question of which estimator is statistically superior depends on the specific shape of the filter employed for peak finding; suboptimal choices of the estimator+filter combination can result in a suppression of the number of high peaks by orders of magnitude. Magnification and size bias generally act to increase the signal-to-noise {nu} of shear peaks; for high peaks the boost can be as large as {Delta}{nu} {approx} 1-2. Due to the steepness of the peak abundance function, these boosts can result in a significant increase in the observed abundance of shear peaks. A companion paper investigates these same issues within the context of stacked weak-lensing mass estimates.

  1. Greatest Moments in Interpersonal Communication: Peak Communication Experiencing.

    ERIC Educational Resources Information Center

    Gordon, Ron

    In an exploratory study of peak communication experiences (PCEs), 36 male and 50 female undergraduates from a speech communication course were asked to describe their PCEs using 19 descriptors derived from A. Maslow's model of the generalized peak experience. Two-thirds or more of both sexes used 10 of these 19 descriptors to characterize their…

  2. Peak Alert Time and Rapport between Residence Hall Roommates.

    ERIC Educational Resources Information Center

    Carey, John C.; And Others

    1988-01-01

    Examined whether peak alert time is related to compatibility for college roommates. Data from 66 male pairs and from 55 female pairs of roommates revealed that pairs who were similar on self-reported peak circadian alertness had higher levels of rapport. (Author/NB)

  3. 27 CFR 9.220 - Pine Mountain-Cloverdale Peak.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...—California, 1960, photoinspected 1975; and (3) Highland Springs Quadrangle—California, 1959, photorevised... straight line, crossing onto the Asti map, to the unnamed 2,769-foot peak located south of Salty Spring... Highland Springs map, to the unnamed 2,792-foot peak in the northeast quadrant of section 21, T12N,...

  4. 46. Peaks of Otter. View of the Johnson Farm, one ...

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

    46. Peaks of Otter. View of the Johnson Farm, one of two historic structures left at peak of otter. The farm's interpretation focuses on the 1930's. Looking southeast. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  5. 42. Peaks of Otter, Abbott Lake. View across lake to ...

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

    42. Peaks of Otter, Abbott Lake. View across lake to peaks of Outter Lodge, completed in 1964. Construction of the lake got underway in 1964. Looking east-northeast. - Blue Ridge Parkway, Between Shenandoah National Park & Great Smoky Mountains, Asheville, Buncombe County, NC

  6. PAVIS: a tool for Peak Annotation and Visualization.

    PubMed

    Huang, Weichun; Loganantharaj, Rasiah; Schroeder, Bryce; Fargo, David; Li, Leping

    2013-12-01

    We introduce a web-based tool, Peak Annotation and Visualization (PAVIS), for annotating and visualizing ChIP-seq peak data. PAVIS is designed with non-bioinformaticians in mind and presents a straightforward user interface to facilitate biological interpretation of ChIP-seq peak or other genomic enrichment data. PAVIS, through association with annotation, provides relevant genomic context for each peak, such as peak location relative to genomic features including transcription start site, intron, exon or 5'/3'-untranslated region. PAVIS reports the relative enrichment P-values of peaks in these functionally distinct categories, and provides a summary plot of the relative proportion of peaks in each category. PAVIS, unlike many other resources, provides a peak-oriented annotation and visualization system, allowing dynamic visualization of tens to hundreds of loci from one or more ChIP-seq experiments, simultaneously. PAVIS enables rapid, and easy examination and cross-comparison of the genomic context and potential functions of the underlying genomic elements, thus supporting downstream hypothesis generation. PMID:24008416

  7. 46 CFR 171.090 - Aft peak bulkhead.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Aft peak bulkhead. 171.090 Section 171.090 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY SPECIAL RULES PERTAINING TO VESSELS CARRYING PASSENGERS Additional Subdivision Requirements § 171.090 Aft peak bulkhead. (a) Each of the following vessels must have an...

  8. Psychological Preparation for Peak Performance in Sports Competition

    ERIC Educational Resources Information Center

    Ohuruogu, Ben; Jonathan, Ugwuanyi I.; Ikechukwu, Ugwu Jude

    2016-01-01

    This paper attempts to make an overview of various techniques, sport psychologist adopt in psychological preparation of athletes for peak performance. To attain peak performance in sports competitions, coaches and athletes should not base their prospect on physical training on sport skills alone rather should integrate both the mental and physical…

  9. A rise in peak performance age in female athletes.

    PubMed

    Elmenshawy, Ahmed R; Machin, Daniel R; Tanaka, Hirofumi

    2015-06-01

    It was reported in 1980s that ages at which peak performance was observed had remained remarkably stable in the past century, although absolute levels of athletic performance increased dramatically for the same time span. The emergence of older (masters) athletes in the past few decades has changed the demographics and age-spectrum of Olympic athletes. The primary aim of the present study was to determine whether the ages at which peak performance was observed had increased in the recent decades. The data spanning 114 years from the first Olympics (1898) to the most recent Olympics (2014) were collected using the publically available data. In the present study, ages at which Olympic medals (gold, silver, and bronze) were won were used as the indicators of peak performance age. Track and field, swimming, rowing, and ice skating events were analyzed. In men, peak performance age did not change significantly in most of the sporting events (except in 100 m sprint running). In contrast, peak performance ages in women have increased significantly since 1980s and consistently in all the athletic events examined. Interestingly, as women's peak performance age increased, they became similar to men's peak ages in many events. In the last 20-30 years, ages at which peak athletic performance is observed have increased in women but not in men. PMID:26022534

  10. Understanding the double peaked El Niño in coupled GCMs

    NASA Astrophysics Data System (ADS)

    Graham, Felicity S.; Wittenberg, Andrew T.; Brown, Jaclyn N.; Marsland, Simon J.; Holbrook, Neil J.

    2016-06-01

    Coupled general circulation models (CGCMs) simulate a diverse range of El Niño-Southern Oscillation behaviors. "Double peaked" El Niño events—where two separate centers of positive sea surface temperature (SST) anomalies evolve concurrently in the eastern and western equatorial Pacific—have been evidenced in Coupled Model Intercomparison Project version 5 CGCMs and are without precedent in observations. The characteristic CGCM double peaked El Niño may be mistaken for a central Pacific warming event in El Niño composites, shifted westwards due to the cold tongue bias. In results from the Australian Community Climate and Earth System Simulator coupled model, we find that the western Pacific warm peak of the double peaked El Niño event emerges due to an excessive westward extension of the climatological cold tongue, displacing the region of strong zonal SST gradients towards the west Pacific. A coincident westward shift in the zonal current anomalies reinforces the western peak in SST anomalies, leading to a zonal separation between the warming effect of zonal advection (in the west Pacific) and that of vertical advection (in the east Pacific). Meridional advection and net surface heat fluxes further drive growth of the western Pacific warm peak. Our results demonstrate that understanding historical CGCM El Niño behaviors is a necessary precursor to interpreting projections of future CGCM El Niño behaviors, such as changes in the frequency of eastern Pacific El Niño events, under global warming scenarios.

  11. The effect of Ni pre-implantation on surface morphology and optical absorption properties of Ag nanoparticles embedded in SiO2

    NASA Astrophysics Data System (ADS)

    Shen, Yanyan; Qi, Ting; Qiao, Yu; Yu, Shengwang; Hei, Hongjun; He, Zhiyong

    2016-02-01

    The effect of Ni ion fluence on Ag nucleation and particle growth was investigated by sequentially implantation of 60 keV Ni ions at fluences of 1 × 1016, 5 × 1016, 1 × 1017 ions/cm2 and 70 keV Ag ions at a fluence of 5 × 1016 ions/cm2. Due to the modification of the deposition and accumulation process of Ag implants caused by Ni pre-implantation, the surface morphology, structures, and optical absorption properties of the Ag nanoparticles (NPs) depends strongly on the Ni fluences. UV-vis absorption spectroscopy study showed that the introducing of Ni atoms lead to intensity decrease in the Ag SPR band. Remarkable local concentration increase of Ag profiles appeared for the sample pre-implanted by Ni ions of 5.0 × 1016 ions/cm2. In particular, the AgNi alloy NPs with dual absorption peaks centered at 406 nm and 563 nm have been formed after 600 °C annealing in Ar atmosphere. However, at a low fluence of 1.0 × 1016 ions/cm2, only small increase of the local Ag concentration than the Ag ions singly implanted sample can be observed. At a high fluence of 1.0 × 1017 ions/cm2, lots Ag atoms are trapped close to the surface, which result in heavy sputtering loss of Ag atoms and the sublimation of Ag atoms after 600 °C annealing.

  12. Laser Absorption Measurements of Equivalence Ratios Studied Along With Their Coupling to Pressure Fluctuations in Lean Premixed Prevaporized (LPP) Combustion

    NASA Technical Reports Server (NTRS)

    Nguyen, Quang-Viet

    2001-01-01

    Concerns about damaging the Earth's ozone layer as a result of high levels of nitrogen oxides (known collectively as NOx) from high-altitude, high-speed aircraft have prompted the study of lean premixed prevaporized (LPP) combustion in aircraft engines. LPP combustion reduces NOx emissions principally by reducing the peak flame temperatures inside an engine. Recent advances in LPP technologies have realized exceptional reductions in pollutant emissions (single-digit ppm NOx for example). However, LPP combustion also presents major challenges: combustion instability and dynamic coupling effects between fluctuations in heat-release rate, dynamic pressure, and fuel pressure. These challenges are formidable and can literally shake an engine apart if uncontrolled. To better understand this phenomenon so that it can be controlled, we obtained real-time laser absorption measurements of the fuel vapor concentration (and equivalence ratio) simultaneously with the dynamic pressure, flame luminosity, and time-averaged gaseous emissions measurements in a research-type jet-A-fueled LPP combustor. The measurements were obtained in NASA Glenn Research Center's CE-5B optically accessible flame tube facility. The CE-5B facility provides inlet air temperatures and pressures similar to the actual operating conditions of real aircraft engines. The laser absorption measurements were performed using an infrared 3.39 micron HeNe laser in conjunction with a visible HeNe laser for liquid droplet scattering compensation.

  13. Measurements of atmospheric NO3 radicals in Hefei using LED-based long path differential optical absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Xue, Lu; Min, Qin; Pin-Hua, Xie; Jun, Duan; Wu, Fang; Liu-Yi, Ling; Lan-Lan, Shen; Jian-Guo, Liu; Wen-Qing, Liu

    2016-02-01

    NO3 radicals accumulate during the night, thereby being the most critical night oxidant. Owing to the low concentration and dramatic variation, the detection of atmospheric NO3 radicals is still challenging. In this paper, an LED-based Long Path Differential Optical Absorption Spectroscopy (LPDOAS) instrument is developed for measuring the atmospheric NO3 radicals. This instrument is composed of a Schmidt-Cassegrain telescope, a combined emitting and receiving fiber, and a red LED equipped with a thermostat, and has a center wavelength of 660 nm, covering the NO3 strongest absorption peak (662 nm). The influence of LED temperature fluctuations is discussed. The temperature of the LED lamp with a home-made thermostat is tested, showing a stability of ±0.1 °C. The principle and fitting analyses of LED-LPDOAS are presented. A retrieval example and a time series of NO3 radical concentrations with good continuity for one night are shown. The detection limit of NO3 for 2.6-km optical path is about 10 ppt. Project supported by the “Strategic Priority Research Program” of the Chinese Academy of Sciences (Grant Nos. XDB05040200 and XDB05010500).

  14. Investigation on optical absorption properties of ion irradiated single walled carbon nanotubes

    SciTech Connect

    Vishalli, Dharamvir, Keya; Kaur, Ramneek; Raina, K. K.; Avasthi, D. K.; Jeet, Kiran

    2015-08-28

    In the present study change in the optical absorption properties of single walled carbon nanotubes (SWCNTs) under nickel ion (60 MeV) irradiation at various fluences has been investigated. Langmuir Blodgett technique is used to deposit SWCNT thin film of uniform thickness. AFM analysis shows a network of interconnected bundles of nanotubes. UV-Vis-NIR absorption spectra indicate that the sample mainly contain SWCNTs of semiconducting nature. It has been found in absorption spectra that there is decrease in the intensity of the characteristic SWCNT peaks with increase in fluence. At fluence value 1×10{sup 14} ions/cm{sup 2} there is almost complete suppression of the characteristic SWCNTs peaks.The decrease in the optical absorption with increase in fluence is due to the increase in the disorder in the system which leads to the decrease in optically active states.

  15. Peak acceleration during impact with helmet materials: effects of impactor mass and speed.

    PubMed

    Hutchinson, Timothy Paul

    2014-01-01

    The impact properties of six foam materials used for energy absorption as the liner of children's helmets, reported by Gimbel and Hoshizaki are considered further. In high-energy impacts, almost complete compression of the energy-absorbing material (bottoming out) may occur, and the severity of the impact increases greatly. Too soft a material means bottoming out occurs at low speeds, but if it is too stiff, the material itself is injurious. The fitting of equations to results in 'no bottoming out' and 'bottoming out' conditions may help assessment of what compromise is appropriate. The equations in this article correspond to peak acceleration being proportional to power functions of impactor speed and mass. 1. When there was no bottoming out, peak acceleration was found to be proportional to m (∧)(c-1).v (∧)(2c), with c being approximately 0.25. 2. For bottoming out, peak acceleration was found to be proportional to m (∧)(p).v (∧)(q), with p and q being approximately 2 and approximately 3. 3. The constants of proportionality were related to material density in a regular way. PMID:24444232

  16. Percutaneous absorption of Octopirox.

    PubMed

    Black, J G; Kamat, V B

    1988-01-01

    containing 1% Octopirox is 29,400, so that the possibility of systemic effects due to absorption through the skin is remote. PMID:3345970

  17. Resonant Absorption of Bessel Beams

    NASA Astrophysics Data System (ADS)

    Fan, J.; Parra, E.; Milchberg, H. M.

    1999-11-01

    We report the first observation of enhanced laser-plasma optical absorption in a subcritical density plasma resulting from spatial resonances, here in the laser breakdown of a gas with a Bessel beam. The enhancement in absorption is directly correlated to enhancements both in confinement of laser radiation to the plasma and in its heating. Under certain conditions, azimuthal asymmetry in the laser beam is essential for efficient gas breakdown. Simulations of this absorption consistently explain the experimental observations. This work is supported by the National Science Foundation (PHY-9515509) and the US Department of Energy (DEF G0297 ER 41039).

  18. Peak-Seeking Optimization of Trim for Reduced Fuel Consumption: Architecture and Performance Predictions

    NASA Technical Reports Server (NTRS)

    Schaefer, Jacob; Brown, Nelson A.

    2013-01-01

    A peak-seeking control approach for real-time trim configuration optimization for reduced fuel consumption has been developed by researchers at the National Aeronautics and Space Administration (NASA) Dryden Flight Research Center to address the goals of the NASA Environmentally Responsible Aviation project to reduce fuel burn and emissions. The peak-seeking control approach is based on a steepest-descent algorithm using a time-varying Kalman filter to estimate the gradient of a performance function of fuel flow versus control surface positions. In real-time operation, deflections of symmetric ailerons, trailing-edge flaps, and leading-edge flaps of an F/A-18 airplane (McDonnell Douglas, now The Boeing Company, Chicago, Illinois) are controlled for optimization of fuel flow. This paper presents the design and integration of this peak-seeking controller on a modified NASA F/A-18 airplane with research flight control computers. A research flight was performed to collect data to build a realistic model of the performance function and characterize measurement noise. This model was then implemented into a nonlinear six-degree-of-freedom F/A-18 simulation along with the peak-seeking control algorithm. With the goal of eventual flight tests, the algorithm was first evaluated in the improved simulation environment. Results from the simulation predict good convergence on minimum fuel flow with a 2.5-percent reduction in fuel flow relative to the baseline trim of the aircraft.

  19. Peak-Seeking Optimization of Trim for Reduced Fuel Consumption: Architecture and Performance Predictions

    NASA Technical Reports Server (NTRS)

    Schaefer, Jacob; Brown, Nelson

    2013-01-01

    A peak-seeking control approach for real-time trim configuration optimization for reduced fuel consumption has been developed by researchers at the National Aeronautics and Space Administration (NASA) Dryden Flight Research Center to address the goals of the NASA Environmentally Responsible Aviation project to reduce fuel burn and emissions. The peak-seeking control approach is based on a steepest-descent algorithm using a time-varying Kalman filter to estimate the gradient of a performance function of fuel flow versus control surface positions. In real-time operation, deflections of symmetric ailerons, trailing-edge flaps, and leading-edge flaps of an FA-18 airplane (McDonnell Douglas, now The Boeing Company, Chicago, Illinois) are controlled for optimization of fuel flow. This presentation presents the design and integration of this peak-seeking controller on a modified NASA FA-18 airplane with research flight control computers. A research flight was performed to collect data to build a realistic model of the performance function and characterize measurement noise. This model was then implemented into a nonlinear six-degree-of-freedom FA-18 simulation along with the peak-seeking control algorithm. With the goal of eventual flight tests, the algorithm was first evaluated in the improved simulation environment. Results from the simulation predict good convergence on minimum fuel flow with a 2.5-percent reduction in fuel flow relative to the baseline trim of the aircraft.

  20. Atmospheric pressure and temperature profiling using near IR differential absorption lidar

    NASA Technical Reports Server (NTRS)

    Korb, C. L.; Schwemmer, G. K.; Dombrowski, M.; Weng, C. Y.

    1983-01-01

    The present investigation is concerned with differential absorption lidar techniques for remotely measuring the atmospheric temperature and pressure profile, surface pressure, and cloud top pressure-height. The procedure used in determining the pressure is based on the conduction of high-resolution measurements of absorption in the wings of lines in the oxygen A band. Absorption with respect to these areas is highly pressure sensitive in connection with the mechanism of collisional line broadening. The method of temperature measurement utilizes a determination of the absorption at the center of a selected line in the oxygen A band which originates from a quantum state with high ground state energy.

  1. Development of an Ionic-Liquid Absorption Heat Pump

    SciTech Connect

    Holcomb, Don

    2011-03-29

    Solar Fueled Products (SFP) is developing an innovative ionic-liquid absorption heat pump (ILAHP). The development of an ILAHP is extremely significant, as it could result in annual savings of more than 190 billion kW h of electrical energy and $19 billion. This absorption cooler uses about 75 percent less electricity than conventional cooling and heating units. The ILAHP also has significant environmental sustainability benefits, due to reduced CO2 emissions. Phase I established the feasibility and showed the economic viability of an ILAHP with these key accomplishments: • Used the breakthrough capabilities provided by ionic liquids which overcome the key difficulties of the common absorption coolers. • Showed that the theoretical thermodynamic performance of an ILAHP is similar to existing absorption-cooling systems. • Established that the half-effect absorption cycle reduces the peak generator temperature, improving collector efficiency and reducing collector area. • Component testing demonstrated that the most critical components, absorber and generator, operate well with conventional heat exchangers. • Showed the economic viability of an ILAHP. The significant energy savings, sustainability benefits, and economic viability are compelling reasons to continue the ILAHP development.

  2. Absorption Mode FT-ICR Mass Spectrometry Imaging

    SciTech Connect

    Smith, Donald F.; Kilgour, David P.; Konijnenburg, Marco; O'Connor, Peter B.; Heeren, Ronald M.

    2013-12-03

    Fourier transform ion cyclotron resonance mass spectrometry offers the highest mass resolving power for molecular imaging experiments. This high mass resolving power ensures that closely spaced peaks at the same nominal mass are resolved for proper image generation. Typically higher magnetic fields are used to increase mass resolving power. However, a gain in mass resolving power can also be realized by phase correction of the data for absorption mode display. In addition to mass resolving power, absorption mode offers higher mass accuracy and signal-to-noise ratio over the conventional magnitude mode. Here we present the first use of absorption mode for Fourier transform ion cyclotron resonance mass spectrometry imaging. The Autophaser algorithm is used to phase correct each spectrum (pixel) in the image and then these parameters are used by the Chameleon work-flow based data processing software to generate absorption mode ?Datacubes? for image and spectral viewing. Absorption mode reveals new mass and spatial features that are not resolved in magnitude mode and results in improved selected ion image contrast.

  3. Infrared absorption spectra of molecular crystals: Possible evidence for small-polaron formation?

    NASA Astrophysics Data System (ADS)

    Pržulj, Željko; Čevizović, Dalibor; Zeković, Slobodan; Ivić, Zoran

    2008-09-01

    The temperature dependence of the position of the so-called anomalous band peaked at 1650cm in the IR-absorption spectrum of crystalline acetanilide (ACN) is theoretically investigated within the small-polaron theory. Its pronounced shift towards the position of the normal band is predicted with the rise of temperature. Interpretation of the IR-absorption spectra in terms of small-polaron model has been critically assessed on the basis of these results.

  4. Optical Parametric Amplification for High Peak and Average Power

    SciTech Connect

    Jovanovic, I

    2001-11-26

    Optical parametric amplification is an established broadband amplification technology based on a second-order nonlinear process of difference-frequency generation (DFG). When used in chirped pulse amplification (CPA), the technology has been termed optical parametric chirped pulse amplification (OPCPA). OPCPA holds a potential for producing unprecedented levels of peak and average power in optical pulses through its scalable ultrashort pulse amplification capability and the absence of quantum defect, respectively. The theory of three-wave parametric interactions is presented, followed by a description of the numerical model developed for nanosecond pulses. Spectral, temperature and angular characteristics of OPCPA are calculated, with an estimate of pulse contrast. An OPCPA system centered at 1054 nm, based on a commercial tabletop Q-switched pump laser, was developed as the front end for a large Nd-glass petawatt-class short-pulse laser. The system does not utilize electro-optic modulators or multi-pass amplification. The obtained overall 6% efficiency is the highest to date in OPCPA that uses a tabletop commercial pump laser. The first compression of pulses amplified in highly nondegenerate OPCPA is reported, with the obtained pulse width of 60 fs. This represents the shortest pulse to date produced in OPCPA. Optical parametric amplification in {beta}-barium borate was combined with laser amplification in Ti:sapphire to produce the first hybrid CPA system, with an overall conversion efficiency of 15%. Hybrid CPA combines the benefits of high gain in OPCPA with high conversion efficiency in Ti:sapphire to allow significant simplification of future tabletop multi-terawatt sources. Preliminary modeling of average power limits in OPCPA and pump laser design are presented, and an approach based on cascaded DFG is proposed to increase the average power beyond the single-crystal limit. Angular and beam quality effects in optical parametric amplification are modeled

  5. Evaluation of different time domain peak models using extreme learning machine-based peak detection for EEG signal.

    PubMed

    Adam, Asrul; Ibrahim, Zuwairie; Mokhtar, Norrima; Shapiai, Mohd Ibrahim; Cumming, Paul; Mubin, Marizan

    2016-01-01

    Various peak models have been introduced to detect and analyze peaks in the time domain analysis of electroencephalogram (EEG) signals. In general, peak model in the time domain analysis consists of a set of signal parameters, such as amplitude, width, and slope. Models including those proposed by Dumpala, Acir, Liu, and Dingle are routinely used to detect peaks in EEG signals acquired in clinical studies of epilepsy or eye blink. The optimal peak model is the most reliable peak detection performance in a particular application. A fair measure of performance of different models requires a common and unbiased platform. In this study, we evaluate the performance of the four different peak models using the extreme learning machine (ELM)-based peak detection algorithm. We found that the Dingle model gave the best performance, with 72 % accuracy in the analysis of real EEG data. Statistical analysis conferred that the Dingle model afforded significantly better mean testing accuracy than did the Acir and Liu models, which were in the range 37-52 %. Meanwhile, the Dingle model has no significant difference compared to Dumpala model. PMID:27462484

  6. NOTE: Absorption spectra variations of EBT radiochromic film from radiation exposure

    NASA Astrophysics Data System (ADS)

    Butson, M. J.; Cheung, T.; Yu, P. K. N.

    2005-07-01

    Gafchromic EBT radiochromic film is one of the newest radiation-induced auto-developing x-ray analysis films available for therapeutic radiation dosimetry in radiotherapy applications. The spectral absorption properties in the visible wavelengths have been investigated and results show two main peaks in absorption located at 636 nm and 585 nm. These absorption peaks are different to many other radiochromic film products such as Gafchromic MD-55 and HS film where two peaks were located at 676 nm and 617 nm respectively. The general shape of the absorption spectra is similar to older designs. A much higher sensitivity is found at high-energy x-rays with an average 0.6 OD per Gy variation in OD seen within the first Gy measured at 636 nm using 6 MV x-rays. This is compared to approximately 0.09 OD units for the first Gy at the 676 nm absorption peak for HS film at 6 MV x-ray energy. The film's blue colour is visually different from older varieties of Gafchromic film with a higher intensity of mid-range blue within the film. The film provides adequate relative absorbed dose measurement for clinical radiotherapy x-ray assessment in the 1 2 Gy dose range which with further investigation may be useful for fractionated radiotherapy dose assessment.

  7. Absorption spectrum of the PbS-doped silica fibers fabricated by ALD and MCVD

    NASA Astrophysics Data System (ADS)

    Ye, Tang; Wen, Jianxiang; Dong, Yanhua; Wang, Tingyun

    2012-11-01

    The technique of atomic layer deposition (ALD) has been introduced to fabricate PbS-doped silica fibers, whose absorption peaks are discovered to be shifted from 1230 nm to 920 nm when the number of ALD deposition cycles varies from 80 to 30 during optical fiber preform fabrication. This is explained by suggesting that the PbS doped in fiber are under the 3D quantum confinement, i.e., quantum dots (QDs). An effective-mass approximat ion of the PbS QDs ' sizes is then made to show the shift of absorption peaks can be attributed to the change of size distribution of these dots.

  8. Reduction in peak oxygen uptake after prolonged bed rest

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Kozlowski, S.

    1982-01-01

    The hypothesis that the magnitude of the reduction in peak oxygen uptake (VO2) after bed rest is directly proportional to the level of pre-bed rest peak VO2 is tested. Complete pre and post-bed rest working capacity and body weight data were obtained from studies involving 24 men (19-24 years old) and 8 women (23-34 years old) who underwent bed rest for 14-20 days with no remedial treatments. Results of regression analyses of the present change in post-bed rest peak VO2 on pre-bed rest peak VO2 with 32 subjects show correlation coefficients of -0.03 (NS) for data expressed in 1/min and -0.17 for data expressed in ml/min-kg. In addition, significant correlations are found that support the hypothesis only when peak VO2 data are analyzed separately from studies that utilized the cycle ergometer, particularly with subjects in the supine position, as opposed to data obtained from treadmill peak VO2 tests. It is concluded that orthostatic factors, associated with the upright body position and relatively high levels of physical fitness from endurance training, appear to increase the variability of pre and particularly post-bed rest peak VO2 data, which would lead to rejection of the hypothesis.

  9. The rediscovery of absorption chillers

    SciTech Connect

    Katzel, J.

    1992-04-23

    Absorption chillers are back - and for two very good reasons: they are environmentally sound and, in many cases, economically attractive. One factor fueling this resurgence is the outlook for natural gas, the energy source of most absorption systems. Deregulation has spurred exploration, and forecasts indicate an abundant supply and relatively low prices through 2050. Threats of global warming and depletion of the ozone layer also are forces driving the absorption chiller market. Being a good corporate citizen today means minimizing or eliminating the use of chlorofluorocarbons (CFCs), the basis of many refrigerants used in mechanical chillers. Even as chemical and chiller manufacturers alike work to develop substitute refrigerants, the perfect alternative has yet to be found. Absorption units are free of these problems, a benefit that appeals to many people.

  10. Understanding Human Motion Skill with Peak Timing Synergy

    NASA Astrophysics Data System (ADS)

    Ueno, Ken; Furukawa, Koichi

    The careful observation of motion phenomena is important in understanding the skillful human motion. However, this is a difficult task due to the complexities in timing when dealing with the skilful control of anatomical structures. To investigate the dexterity of human motion, we decided to concentrate on timing with respect to motion, and we have proposed a method to extract the peak timing synergy from multivariate motion data. The peak timing synergy is defined as a frequent ordered graph with time stamps, which has nodes consisting of turning points in motion waveforms. A proposed algorithm, PRESTO automatically extracts the peak timing synergy. PRESTO comprises the following 3 processes: (1) detecting peak sequences with polygonal approximation; (2) generating peak-event sequences; and (3) finding frequent peak-event sequences using a sequential pattern mining method, generalized sequential patterns (GSP). Here, we measured right arm motion during the task of cello bowing and prepared a data set of the right shoulder and arm motion. We successfully extracted the peak timing synergy on cello bowing data set using the PRESTO algorithm, which consisted of common skills among cellists and personal skill differences. To evaluate the sequential pattern mining algorithm GSP in PRESTO, we compared the peak timing synergy by using GSP algorithm and the one by using filtering by reciprocal voting (FRV) algorithm as a non time-series method. We found that the support is 95 - 100% in GSP, while 83 - 96% in FRV and that the results by GSP are better than the one by FRV in the reproducibility of human motion. Therefore we show that sequential pattern mining approach is more effective to extract the peak timing synergy than non-time series analysis approach.

  11. Comparison of the manganese oxygen-evolving complex in photosystem II of spinach and Synechococcus sp. with multinuclear manganese model compounds by X-ray absorption spectroscopy

    SciTech Connect

    DeRose, V.J.; Mukerji, I.; Latimer, M.J. ); Yachandra, V.K.; Klein, M.P. ); Sauer, K. Lawrence Berkeley Lab., CA )

    1994-06-15

    The evaluation of Mn X-ray absorption fine structure (EXAFS) studies on the oxygen-evolving complex (OEC) from photosystem II is described for preparations from both spinach and the cyanobacterium Synechococcus sp. poised in the S[sub 1] and S[sub 2] states. In addition to reproducing previous results suggesting the presence of bis([mu]-oxo)-bridged Mn centers in the OEC, a Fourier transform peak due to scatterers at an average distance of > 3 [angstrom] is detected in both types of preparation. In addition, subtle but reproducible changes are found in the relative amplitudes of the Fourier transform peaks due to mainly O ([approximately]1.8 [angstrom]) and Mn ([approximately] 2.7 [angstrom]) neighbors upon cryogenic advance from the S[sub 1] to the S[sub 2] state. Analysis of the peak due to scatterers at [approximately] 3 [angstrom] favors assignment to (per 4 Mn in the OEC) 1-2 heavy atom (Mn, Ca) scatterers at an average distance of 3.3-3.4 [angstrom]. The EXAFS data of several multinuclear Mn model compounds containing such scattering interactions are analyzed and compared with the data for the OEC. Structural models for the OEC are evaluated on the basis of these results. 40 refs., 9 figs., 5 tabs.

  12. Peak Oil, Urban Form, and Public Health: Exploring the Connections

    PubMed Central

    Kaza, Nikhil; Knaap, Gerrit-Jan; Knaap, Isolde

    2011-01-01

    We assessed the relationships between peak oil and urban form, travel behavior, and public health. Peak oil will affect the general economy, travel behavior, and urban form through income and substitution effects; however, because of the wide range of substitution possibilities, the impacts are likely to be gradual and relatively small. Furthermore, we suggest that changes in travel behavior and increases in urban density will have both favorable and unfavorable effects on public health. To mitigate the adverse impacts and to maximize the positive effects of peak oil, we recommend that careful attention should be paid to urban design and public health responses for a range of urbanization patterns. PMID:21778494

  13. A model of peak production in oil fields

    NASA Astrophysics Data System (ADS)

    Abrams, Daniel M.; Wiener, Richard J.

    2010-01-01

    We developed a model for oil production on the basis of simple physical considerations. The model provides a basic understanding of Hubbert's empirical observation that the production rate for an oil-producing region reaches its maximum when approximately half the recoverable oil has been produced. According to the model, the oil production rate at a large field must peak before drilling peaks. We use the model to investigate the effects of several drilling strategies on oil production. Despite the model's simplicity, predictions for the timing and magnitude of peak production match data on oil production from major oil fields throughout the world.

  14. Giant backscattering peak in angle-resolved Andreev reflection

    SciTech Connect

    Beenakker, C.W.J.; Melsen, J.A.; Brouwer, P.W.

    1995-05-15

    It is shown analytically and by numerical simulation that the angular distribution of Andreev reflection by a disordered normal-metal--superconductor junction has a narrow peak at the angle of incidence. The peak is higher than the well-known coherent backscattering peak in the normal state, by a large factor {ital G}/{ital G}{sub 0} (where {ital G} is the conductance of the junction and {ital G}{sub 0}=2{ital e}{sup 2}/{ital h}). The enhanced backscattering can be detected by means of ballistic point contacts.

  15. Multi-peak accumulation and coarse modes observed from AERONET retrieved aerosol volume size distribution in Beijing

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Li, Zhengqiang; Zhang, Yuhuan; Chen, Yu; Cuesta, Juan; Ma, Yan

    2016-01-01

    We present characteristic peaks of atmospheric columnar aerosol volume size distribution retrieved from the AErosol RObotic NETwork (AERONET) ground-based Sun-sky radiometer observation, and their correlations with aerosol optical properties and meteorological conditions in Beijing over 2013. The results show that the aerosol volume particle size distribution (VPSD) can be decomposed into up to four characteristic peaks, located in accumulation and coarse modes, respectively. The mean center radii of extra peaks in accumulation and coarse modes locate around 0.28 (±0.09) to 0.38 (±0.11) and 1.25 (±0.56) to 1.47 (±0.30) μm, respectively. The multi-peak size distributions are found in different aerosol loading conditions, with the mean aerosol optical depth (440 nm) of 0.58, 0.49, 1.18 and 1.04 for 2-, 3-I/II and 4-peak VPSD types, while the correspondingly mean relative humidity values are 58, 54, 72 and 67 %, respectively. The results also show the significant increase (from 0.25 to 0.40 μm) of the mean extra peak median radius in the accumulation mode for the 3-peak-II cases, which agrees with aerosol hygroscopic growth related to relative humidity and/or cloud or fog processing.

  16. Multi-peak accumulation and coarse modes observed from AERONET retrieved aerosol volume size distribution in Beijing

    NASA Astrophysics Data System (ADS)

    Zhang, Ying; Li, Zhengqiang; Zhang, Yuhuan; Chen, Yu; Cuesta, Juan; Ma, Yan

    2016-08-01

    We present characteristic peaks of atmospheric columnar aerosol volume size distribution retrieved from the AErosol RObotic NETwork (AERONET) ground-based Sun-sky radiometer observation, and their correlations with aerosol optical properties and meteorological conditions in Beijing over 2013. The results show that the aerosol volume particle size distribution (VPSD) can be decomposed into up to four characteristic peaks, located in accumulation and coarse modes, respectively. The mean center radii of extra peaks in accumulation and coarse modes locate around 0.28 (±0.09) to 0.38 (±0.11) and 1.25 (±0.56) to 1.47 (±0.30) μm, respectively. The multi-peak size distributions are found in different aerosol loading conditions, with the mean aerosol optical depth (440 nm) of 0.58, 0.49, 1.18 and 1.04 for 2-, 3-I/II and 4-peak VPSD types, while the correspondingly mean relative humidity values are 58, 54, 72 and 67 %, respectively. The results also show the significant increase (from 0.25 to 0.40 μm) of the mean extra peak median radius in the accumulation mode for the 3-peak-II cases, which agrees with aerosol hygroscopic growth related to relative humidity and/or cloud or fog processing.

  17. Solar Absorptance of Cermet Coatings Evaluated

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.

    2004-01-01

    Cermet coatings, molecular mixtures of metal and ceramic, are being considered for the heat inlet surface of solar Stirling convertors. In this application, the key role of the cermet coating is to absorb as much of the incident solar energy as possible. To achieve this objective, the cermet coating has a high solar absorptance value. Cermet coatings are manufactured utilizing sputter deposition, and many different metal and ceramic combinations can be created. The ability to mix metal and ceramic at the atomic level offers the opportunity to tailor the composition, and hence, the optical properties of these coatings. The NASA Glenn Research Center has prepared and characterized a wide variety of cermet coatings utilizing different metals deposited in an aluminum oxide ceramic matrix. In addition, the atomic oxygen durability of these coatings has been evaluated.

  18. Differential absorption lidar sensing of ozone

    SciTech Connect

    Browell, E.V.

    1989-03-01

    The Differential Absorption Lidar (DIAL) technique has been used since the early 1970s for remote measurements of ozone (O/sub 3/) in the lower atmosphere. To investigate large-scale variations of O/sub 3/ and aerosols in the troposphere and lower stratosphere, a versatile airborne DIAL system was developed in 1980 at the NASA Langley Research Center. This DIAL system currently has the capability to measure O/sub 3/ and multiple-wavelength aerosol profiles to a range of over 8 km above and below the aircraft simultaneously. Eleven major field experiments have been conducted with the NASA air-borne DIAL system since 1980 to study the transport and chemistry related to O/sub 3/ and aerosols. This paper discusses the DIAL technique for deriving O/sub 3/ profiles from lidar measurements. The NASA airborne DIAL system is described, and examples of a broad range of O/sub 3/ and aerosol measurements are presented.

  19. Quantitation of vitamin B 12 by first-derivative absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Karşilayan, Huriye

    1996-08-01

    Quantitation of vitamin B 12 by first-derivative absorption spectroscopy is described. Peak-to-peak (355 nm to 370 nm) amplitudes were measured from the first derivative spectra. The method permits rapid determination of vitamin B 12, and increases the detection limit while decreasing interference by impurities. The effects of the majority of other absorbing macromolecules which may also be present in biological samples are eliminated or very considerably minimized by this method.

  20. Children's cancer centers

    MedlinePlus

    Pediatric cancer center; Pediatric oncology center; Comprehensive cancer center ... Treating childhood cancer is not the same as treating adult cancer. The cancers are different. So are the treatments and the ...

  1. The Watergate Learning Center

    ERIC Educational Resources Information Center

    Training in Business and Industry, 1971

    1971-01-01

    The Watergate Learning Center, recently opened by Sterling Learning Center in Washington, D. C., blueprints the plan established by Sterling and Marriott Hotels for a national chain of learning centers with much the same facilities. (EB)

  2. Fireworks Information Center

    MedlinePlus

    ... Home / Safety Education / Safety Education Centers En Español Fireworks Information Center This is an information center on ... Video Put Safety First This Fourth of July Fireworks Information What are consumer fireworks and where are ...

  3. Discovery of the Most Distant Double-Peaked Emitter at z = 1.369

    NASA Astrophysics Data System (ADS)

    Luo, B.; Brandt, W. N.; Silverman, J. D.; Strateva, I. V.; Bauer, F. E.; Capak, P.; Kartaltepe, J.; Lehmer, B. D.; Mainieri, V.; Salvato, M.; Szokoly, G.; Schneider, D. P.; Vignali, C.

    2009-04-01

    We report the discovery of the most distant double-peaked emitter, CXOECDFS J033115.0-275518, at z = 1.369. A Keck/DEIMOS spectrum shows a clearly double-peaked broad Mg II λ2799 emission line, with FWHM ≈ 11, 000 km s-1 for the line complex. The line profile can be well fitted by an elliptical relativistic Keplerian disk model. This is one of a handful of double-peaked emitters known to be a luminous quasar, with excellent multiwavelength coverage and a high-quality X-ray spectrum. CXOECDFS J033115.0-275518 is a radio-loud quasar with two radio lobes (FR II morphology) and a radio loudness of f 5 GHz/f 4400 Å ≈ 429. The X-ray spectrum can be modeled by a power law with photon index 1.72 and no intrinsic absorption; the rest-frame 0.5-8.0 keV luminosity is 5.0 × 1044 erg s-1. The spectral energy distribution (SED) of CXOECDFS J033115.0-275518 has a shape typical for radio-loud quasars and double-peaked emitters at lower redshift. The local viscous energy released from the line-emitting region of the accretion disk is probably insufficient to power the observed line flux, and external illumination of the disk appears to be required. The presence of a big blue bump in the SED along with the unexceptional X-ray spectrum suggest that the illumination cannot arise from a radiatively inefficient accretion flow.

  4. Optical absorption of nanoporous silicon: quasiparticle band gaps and absorption spectra

    NASA Astrophysics Data System (ADS)

    Shi, Guangsha; Kioupakis, Emmanouil

    2013-03-01

    Silicon is an earth-abundant material of great importance in semiconductors electronics, but its photovoltaic applications are limited by the low absorption coefficient in the visible due to its indirect band gap. One strategy to improve the absorbance is to perforate silicon with nanoscale pores, which introduce carrier scattering that enables optical transitions across the indirect gap. We used density functional and many-body perturbation theory in the GW approximation to investigate the electronic and optical properties of porous silicon for various pore sizes, spacings, and orientations. Our calculations include up to 400 atoms in the unit cell. We will discuss the connection of the band-gap value and absorption coefficient to the underlying nanopore geometry. The absorption coefficient in the visible range is found to be optimal for appropriately chosen nanopore size, spacing, and orientation. Our work allows us to predict porous-silicon structures that may have optimal performance in photovoltaic applications. This research was supported as part of CSTEC, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science. Computational resources were provided by the DOE NERSC facility.

  5. Gamma irradiation effect on Rayleigh scattering in low water peak single-mode optical fibers.

    PubMed

    Wen, Jianxiang; Peng, Gang-Ding; Luo, Wenyun; Xiao, Zhongyin; Chen, Zhenyi; Wang, Tingyun

    2011-11-01

    The Rayleigh scattering loss in low water peak single-mode optical fibers under varying Gamma rays irradiation has been investigated. We observed that the Rayleigh scattering coefficient (CR) of the fiber is almost linearly increased with the increase of Gamma irradiation in the low-dose range (< 500 Gy). Based on the electron spin resonance (ESR) spectra analysis, we confirmed that the Rayleigh scattering mainly results from the irradiation-induced defect centers associated with electron transfer or charge density redistribution around Ge and O atoms. This work provides a new interpretation of the optical loss and reveals a new mechanism on irradiation influence on Rayleigh scattering. PMID:22109205

  6. Accuracy improvement in peak positioning of spectrally distorted fiber Bragg grating sensors by Gaussian curve fitting

    SciTech Connect

    Lee, Hyun-Wook; Park, Hyoung-Jun; Lee, June-Ho; Song, Minho

    2007-04-20

    To improve measurement accuracy of spectrally distorted fiber Bragg grating temperature sensors, reflection profiles were curve fitted to Gaussian shapes, of which center positions were transformed into temperature information.By applying the Gaussian curve-fitting algorithm in a tunable bandpass filter demodulation scheme,{approx}0.3 deg. C temperature resolution was obtained with a severely distorted grating sensor, which was much better than that obtained using the highest peak search algorithm. A binary search was also used to retrieve the optimal fitting curves with the least amount of processing time.

  7. Ulysses solar wind plasma observations from peak southerly latitude through perihelion and beyond

    SciTech Connect

    Phillips, J.L.; Bame, S.J.; Feldman, W.C.; Gosling, J.T.; McComas, D.J.; Goldstein, B.E.; Neugebauer, M.; Hammond, C.M.

    1995-09-01

    We present Ulysses solar wind plasma data from the peak southerly latitude of {minus}80.2{degrees} through +64.9{degrees} latitude on June 7, 1995. Ulysses encountered fast wind throughout this time except for a 43{degrees} band centered on the solar equator. Median mass flux was nearly constant with latitude, while speed and density had positive and negative poleward gradients, respectively. Solar wind momentum flux was highest at high latitudes, suggesting a latitudinal asymmetry in the heliopause cross section. Solar wind energy flux density was also highest at high latitudes.

  8. PolyaPeak: Detecting Transcription Factor Binding Sites from ChIP-seq Using Peak Shape Information

    PubMed Central

    Wu, Hao; Ji, Hongkai

    2014-01-01

    ChIP-seq is a powerful technology for detecting genomic regions where a protein of interest interacts with DNA. ChIP-seq data for mapping transcription factor binding sites (TFBSs) have a characteristic pattern: around each binding site, sequence reads aligned to the forward and reverse strands of the reference genome form two separate peaks shifted away from each other, and the true binding site is located in between these two peaks. While it has been shown previously that the accuracy and resolution of binding site detection can be improved by modeling the pattern, efficient methods are unavailable to fully utilize that information in TFBS detection procedure. We present PolyaPeak, a new method to improve TFBS detection by incorporating the peak shape information. PolyaPeak describes peak shapes using a flexible Pólya model. The shapes are automatically learnt from the data using Minorization-Maximization (MM) algorithm, then integrated with the read count information via a hierarchical model to distinguish true binding sites from background noises. Extensive real data analyses show that PolyaPeak is capable of robustly improving TFBS detection compared with existing methods. An R package is freely available. PMID:24608116

  9. Peak Doctor v 1.0.0 Labview Version

    2014-05-29

    PeakDoctor software works interactively with its user to analyze raw gamma-ray spectroscopic data. The goal of the software is to produce a list of energies and areas of all of the peaks in the spectrum, as accurately as possible. It starts by performing an energy calibration, creating a function that describes how energy can be related to channel number. Next, the software determines which channels in the raw histogram are in the Compton continuum andmore » which channels are parts of a peak. Then the software fits the Compton continuum with cubic polynomials. The last step is to fit all of the peaks with Gaussian functions, thus producing the list.« less

  10. Corona discharge ionization of paracetamol molecule: Peak assignment

    NASA Astrophysics Data System (ADS)

    Bahrami, H.; Farrokhpour, H.

    2015-01-01

    Ionization of paracetamol was investigated using ion mobility spectrometry equipped with a corona discharge ionization source. The measurements were performed in the positive ion mode and three peaks were observed in the ion mobility spectrum. Experimental evidence and theoretical calculations were used to correlate the peaks to related ionic species of paracetamol. Two peaks were attributed to protonated isomers of paracetamol and the other peak was attributed to paracetamol fragment ions formed by dissociation of the N-C bond after protonation of the nitrogen atom. It was observed that three sites of paracetamol compete for protonation and their relative intensities, depending on the sample concentration. The ratio of ion products could be predicted from the internal proton affinity of the protonation sites at each concentration.

  11. Corona discharge ionization of paracetamol molecule: peak assignment.

    PubMed

    Bahrami, H; Farrokhpour, H

    2015-01-25

    Ionization of paracetamol was investigated using ion mobility spectrometry equipped with a corona discharge ionization source. The measurements were performed in the positive ion mode and three peaks were observed in the ion mobility spectrum. Experimental evidence and theoretical calculations were used to correlate the peaks to related ionic species of paracetamol. Two peaks were attributed to protonated isomers of paracetamol and the other peak was attributed to paracetamol fragment ions formed by dissociation of the N-C bond after protonation of the nitrogen atom. It was observed that three sites of paracetamol compete for protonation and their relative intensities, depending on the sample concentration. The ratio of ion products could be predicted from the internal proton affinity of the protonation sites at each concentration. PMID:25128677

  12. Periodic transmission peak splitting in one dimensional disordered photonic structures

    NASA Astrophysics Data System (ADS)

    Kriegel, Ilka; Scotognella, Francesco

    2016-08-01

    In the present paper we present ways to modulate the periodic transmission peaks arising in disordered one dimensional photonic structures with hundreds of layers. Disordered structures in which the optical length nd (n is the refractive index and d the layer thickness) is the same for each layer show regular peaks in their transmission spectra. A proper variation of the optical length of the layers leads to a splitting of the transmission peaks. Notably, the variation of the occurrence of high and low refractive index layers, gives a tool to tune also the width of the peaks. These results are of highest interest for optical application, such as light filtering, where the manifold of parameters allows a precise design of the spectral transmission ranges.

  13. The Calculation of Adsorption Isotherms from Chromatographic Peak Shapes

    ERIC Educational Resources Information Center

    Neumann, M. G.

    1976-01-01

    Discusses the relationship between adsorption isotherms and elution peak shapes in gas chromatography, and describes a laboratory experiment which involves the adsorption of hexane, cyclohexane, and benzene on alumina at different temperatures. (MLH)

  14. Global flood hazard mapping using statistical peak flow estimates

    NASA Astrophysics Data System (ADS)

    Herold, C.; Mouton, F.

    2011-01-01

    Our aim is to produce a world map of flooded areas for a 100 year return period, using a method based on large rivers peak flow estimates derived from mean monthly discharge time-series. Therefore, the map is supposed to represent flooding that affects large river floodplains, but not events triggered by specific conditions like coastal or flash flooding for instance. We first generate for each basin a set of hydromorphometric, land cover and climatic variables. In case of an available discharge record station at the basin outlet, we base the hundred year peak flow estimate on the corresponding time-series. Peak flow magnitude for basin outlets without gauging stations is estimated by statistical means, performing several regressions on the basin variables. These peak flow estimates enable the computation of corresponding flooded areas using hydrologic GIS processing on digital elevation model.

  15. Detail view of the decorative element at the peak of ...

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

    Detail view of the decorative element at the peak of the gabled dormer of the northwest corner bay of the west façade - Oregon State Fairgrounds Grandstand, 2330 Seventeenth Avenue, Northeast, Salem, Marion, OR

  16. 48. VIEW OF SKYLINE DRIVE FROM THE ROCKY PEAK OF ...

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

    48. VIEW OF SKYLINE DRIVE FROM THE ROCKY PEAK OF STONY MAN MOUNTAIN (EL. 4,011). LOOKING NORTHEAST. STONY MAN OVERLOOK VISIBLE IN THE DISTANCE. - Skyline Drive, From Front Royal, VA to Rockfish Gap, VA , Luray, Page County, VA

  17. Improvements to science operations at Kitt Peak National Observatory

    NASA Astrophysics Data System (ADS)

    Bohannan, Bruce

    1998-07-01

    In recent years Kitt Peak National Observatory has undertaken a number of innovative projects to optimize science operations with the suite of telescopes we operate on Kitt Peak, Arizona. Changing scientific requirements and expectations of our users, evolving technology and declining budgets have motivated the changes. The operations improvements have included telescope performance enhancements--with the focus on the Mayall 4-m--modes of observing and scheduling, telescope control and observing systems, planning and communication, and data archiving.

  18. Standard Test Data and Peak Fitting for XPS Measurements

    National Institute of Standards and Technology Data Gateway

    Standard Test Data and Peak Fitting for XPS Measurements (Web, free access)   This web site provides an extensive set of simulated photoelectron spectroscopy data for users to test software for determining the positions and intensities of overlapping peaks. Users download the data, perform their analyses, and then upload their results. A Java program evaluates the results and provides a graphical presentation of the errors in the user's analyses.

  19. Martian cratering and central peak statistics - Mariner 9 results

    NASA Technical Reports Server (NTRS)

    Cordell, B. M.; Lingenfelter, R. E.; Schubert, G.

    1974-01-01

    Mariner 9 imagery shows that central peaked craters occur much more frequently in the Martian south polar region than in typical equatorial areas, and that both regions have crater size frequency distributions characteristic of saturation. Several arguments indicate that a preferential production mechanism, e.g., pingo formation made possible by subsurface permafrost confined to Martian polar regions, may account for the central peak excess in the south polar region.

  20. Mass-concentration relation and weak lensing peak counts

    NASA Astrophysics Data System (ADS)

    Cardone, V. F.; Camera, S.; Sereno, M.; Covone, G.; Maoli, R.; Scaramella, R.

    2015-02-01

    Context. The statistics of peaks in weak lensing convergence maps is a promising tool for investigating both the properties of dark matter haloes and constraining the cosmological parameters. Aims: We study how the number of detectable peaks and its scaling with redshift depend upon the cluster's dark matter halo profiles and use peak statistics to constrain the parameters of the mass-concentration (MC) relation. We investigate which constraints the Euclid mission can set on the MC coefficients taking degeneracies with the cosmological parameters into account, too. Methods: To this end, we first estimated the number of peaks and its redshift distribution for different MC relations and found that the steeper the mass dependence and the greater the normalisation, the larger the number of detectable clusters, with the total number of peaks changing up to 40% depending on the MC relation. We then performed a Fisher matrix forecast of the errors on the MC relation parameters, as well as on cosmological parameters. Results: We find that peak number counts detected by Euclid can determine the normalization Av, the mass Bv, redshift Cv slopes, and intrinsic scatter σv of the MC relation to an unprecedented accuracy, which is σ(Av) /Av = 1%, σ(Bv) /Bv = 4%, σ(Cv) /Cv = 9%, and σ(σv) /σv = 1% if all cosmological parameters are assumed to be known. If we relax this severe assumption, constraints are degraded, but remarkably good results can be restored by setting only some of the parameters or combining peak counts with Planck data. This precision can give insight into competing scenarios of structure formation and evolution and into the role of baryons in cluster assembling. Alternatively, for a fixed MC relation, future peak counts can perform as well as current BAO and SNeIa when combined with Planck.