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Sample records for rapidly remove spectral

  1. Selective Removal of Residual Orthodontic Composite Using a Rapidly Scanned Carbon Dioxide Laser with Spectral Feedback

    Science.gov (United States)

    Hirasuna, Krista

    Background and Objective: Excessive heat accumulation within the tooth, incomplete removal of composite, and variable damage to the enamel are shortcomings of using conventional burs to remove residual orthodontic composite after debonding fixed appliances. The objective of this study was to determine if composite could be selectively removed from the enamel surface using a rapidly scanned carbon dioxide laser controlled by spectral feedback. Materials and Methods: A carbon dioxide laser operating at a wavelength of 9.3 microm with a pulse duration of 10-15 micros and a pulse repetition rate of ˜ 200 Hz was used to selectively remove composite from the buccal surfaces of 21 extracted teeth. GrenGloo(TM) composite was used to better visualize residual composite and the amount of enamel lost was measured with optical microscopy. A spectral feedback system utilizing a miniature spectrometer was used to control the laser scanning system. Pulpal temperature measurements were performed during composite removal to determine if there was excessive heat accumulation. Results: The amount of enamel lost averaged 22.7microm +/- 8.9 and 25.3 microm +/- 9.4 for removal at 3.8 and 4.2 J/cm2, respectively. An average maximum temperature rise of 1.9°C +/- 1.5 was recorded, with no teeth approaching the critical value of 5.5°C. The average time of composite removal was 19.3 +/- 4.1 seconds. Conclusions: Residual orthodontic composite can be rapidly removed from the tooth surface using a rapidly scanned CO2 laser with spectral feedback, with minimal temperature rise within the pulp and with minimal damage to the underlying enamel surface.

  2. Selective removal of esthetic composite restorations with spectral guided laser ablation

    Science.gov (United States)

    Yi, Ivana; Chan, Kenneth H.; Tsuji, Grant H.; Staninec, Michal; Darling, Cynthia L.; Fried, Daniel

    2016-02-01

    Dental composites are used for a wide range of applications such as fillings for cavities, adhesives for orthodontic brackets, and closure of gaps (diastemas) between teeth by esthetic bonding. Anterior restorations are used to replace missing, diseased and unsightly tooth structure for both appearance and function. When these restorations must be replaced, they are difficult to remove mechanically without causing excessive removal or damage to enamel because dental composites are color matched to teeth. Previous studies have shown that CO2 lasers have high ablation selectivity and are well suited for removal of composite on occlusal surfaces while minimizing healthy tissue loss. A spectral feedback guidance system may be used to discriminate between dental composite and dental hard tissue for selective ablation of composite material. The removal of composite restorations filling diastemas is more challenging due to the esthetic concern for anterior teeth. The objective of this study is to determine if composite spanning a diastema between anterior teeth can be removed by spectral guided laser ablation at clinically relevant rates with minimal damage to peripheral healthy tissue and with higher selectivity than a high speed dental handpiece.

  3. Removable partial dentures: use of rapid prototyping.

    Science.gov (United States)

    Lima, Julia Magalhaes Costa; Anami, Lilian Costa; Araujo, Rodrigo Maximo; Pavanelli, Carlos A

    2014-10-01

    The CAD/CAM technology associated with rapid prototyping (RP) is already widely used in the fabrication of all-ceramic fixed prostheses and in the biomedical area; however, the use of this technology for the manufacture of metal frames for removable dentures is new. This work reports the results of a literature review conducted on the use of CAD/CAM and RP in the manufacture of removable partial dentures. © 2014 by the American College of Prosthodontists.

  4. Spectral Reflectance and Vegetation Index Changes in Deciduous Forest Foliage Following Tree Removal: Potential for Deforestation Monitoring

    Science.gov (United States)

    Peng, D.; Hu, Y.; Li, Z.

    2016-05-01

    It is important to detect and quantify deforestation to guide strategic decisions regarding environment, socioeconomic development, and climate change. In the present study, we conducted a field experiment to examine spectral reflectance and vegetation index changes in poplar and locust tree foliage with different leaf area indices over the course of three sunny days, following tree removal from the canopy. The spectral reflectance of foliage from harvested trees was measured using an ASD FieldSpec Prospectroradiometer; synchronous meteorological data were also obtained. We found that reflectance in short-wave infrared and red-edge reflectance was more time sensitive after tree removal than reflectance in other spectral regions, and that the normalized difference water index (NDWI) and the red-edge chlorophyll index (CIRE) were the preferred indicators of these changes from several indices evaluated. Synthesized meteorological environments were found to influence water and chlorophyll contents after tree removal, and this subsequently changed the spectral canopy reflectance. Our results indicate the potential for such tree removal to be detected with NDWI or CIRE from the second day of a deforestation event.

  5. Rapid and selective removal of composite from tooth surfaces with a 9.3 µm CO2 laser using spectral feedback.

    Science.gov (United States)

    Chan, Kenneth H; Hirasuna, Krista; Fried, Daniel

    2011-09-01

    Dental composite restorative materials are color matched to the tooth and are difficult to remove by mechanical means without excessive removal or damage to peripheral enamel and dentin. Lasers are ideally suited for selective ablation to minimize healthy tissue loss when replacing existing restorations, sealants, or removing composite adhesives such as residual composite left after debonding orthodontic brackets. In this study, a carbon dioxide laser operating at 9.3-µm with a pulse duration of 10-20-microsecond and a pulse repetition rate of ∼200 Hz was integrated with a galvanometer based scanner and used to selectively remove composite from tooth surfaces. Spectra of the plume emission were acquired after each laser pulse and used to differentiate between the ablation of dental enamel or composite. Microthermocouples were used to monitor the temperature rise in the pulp chamber during composite removal. The composite was placed on tooth buccal and occlusal surfaces and the carbon dioxide laser beam was scanned across the surface to selectively remove the composite without excessive damage to the underlying sound enamel. The residual composite and the damage to the underlying enamel was evaluated using optical microscopy. The laser was able to rapidly remove composite from tooth buccal and occlusal surfaces with minimal damage to the underlying sound enamel and without excessive heat accumulation in the tooth. This study demonstrated that composite can be selectively removed from tooth surfaces at clinically relevant rates using a CO(2) laser operating at 9.3-µm with high pulse repetition rates with minimal heat deposition and damage to the underlying enamel. Copyright © 2011 Wiley-Liss, Inc.

  6. Rapid expansion and pseudo spectral implementation for reverse time migration in VTI media

    KAUST Repository

    Pestana, Reynam C

    2012-04-24

    In isotropic media, we use the scalar acoustic wave equation to perform reverse time migration (RTM) of the recorded pressure wavefield data. In anisotropic media, P- and SV-waves are coupled, and the elastic wave equation should be used for RTM. For computational efficiency, a pseudo-acoustic wave equation is often used. This may be solved using a coupled system of second-order partial differential equations. We solve these using a pseudo spectral method and the rapid expansion method (REM) for the explicit time marching. This method generates a degenerate SV-wave in addition to the P-wave arrivals of interest. To avoid this problem, the elastic wave equation for vertical transversely isotropic (VTI) media can be split into separate wave equations for P- and SV-waves. These separate wave equations are stable, and they can be effectively used to model and migrate seismic data in VTI media where |ε- δ| is small. The artifact for the SV-wave has also been removed. The independent pseudo-differential wave equations can be solved one for each mode using the pseudo spectral method for the spatial derivatives and the REM for the explicit time advance of the wavefield. We show numerically stable and high-resolution modeling and RTM results for the pure P-wave mode in VTI media. © 2012 Sinopec Geophysical Research Institute.

  7. Rapid expansion and pseudo spectral implementation for reverse time migration in VTI media

    KAUST Repository

    Pestana, Reynam C; Ursin, Bjø rn; Stoffa, Paul L

    2012-01-01

    In isotropic media, we use the scalar acoustic wave equation to perform reverse time migration (RTM) of the recorded pressure wavefield data. In anisotropic media, P- and SV-waves are coupled, and the elastic wave equation should be used for RTM. For computational efficiency, a pseudo-acoustic wave equation is often used. This may be solved using a coupled system of second-order partial differential equations. We solve these using a pseudo spectral method and the rapid expansion method (REM) for the explicit time marching. This method generates a degenerate SV-wave in addition to the P-wave arrivals of interest. To avoid this problem, the elastic wave equation for vertical transversely isotropic (VTI) media can be split into separate wave equations for P- and SV-waves. These separate wave equations are stable, and they can be effectively used to model and migrate seismic data in VTI media where |ε- δ| is small. The artifact for the SV-wave has also been removed. The independent pseudo-differential wave equations can be solved one for each mode using the pseudo spectral method for the spatial derivatives and the REM for the explicit time advance of the wavefield. We show numerically stable and high-resolution modeling and RTM results for the pure P-wave mode in VTI media. © 2012 Sinopec Geophysical Research Institute.

  8. Mecoprop (MCPP) removal in full-scale rapid sand filters at a groundwater-based waterworks

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen; Arvin, Erik; Corfitzen, Charlotte B.

    2014-01-01

    and secondary rapid sand filters. Water quality parameters were measured throughout the waterworks, and they behaved as designed for. MCPP was removed in secondary rapid sand filters — removal was the greatest in the sand filters in the filter line with the highest contact time (63min). In these secondary sand...... in the full-scale system. Therefore, microcosms were set up with filter sand, water and 14C-labelled MCPP at an initial concentration of 0.2μg/L. After 24h, 79–86% of the initial concentration of MCPP was removed. Sorption removed 11–15%, while the remaining part was removed by microbial processes, leading...... to a complete mineralisation of 13–18%. Microbial removal in the filter sand was similar at different depths of the rapid sand filter, while the amount of MCPP which adsorbed to the filter sand after 48h decreased with depth from 21% of the initial MCPP in the top layer to 7% in the bottom layer...

  9. Search for rapid spectral variability in Psi(9) Aurigae

    International Nuclear Information System (INIS)

    Ghosh, K.K.

    1989-01-01

    Observations of Psi(9) Aur on five nights between January 29 and February 3, 1988 were conducted as part of a search for rapid spectral variability in Be stars. In addition, a series of H-alpha profiles with a time resolution of about 45 s was obtained for the star. A method for obtaining the standard deviation in continuum counts measurements is proposed. The estimated value of the standard deviation of the measured equivalent widths of the H-alpha profiles was obtained using the method of Chalabaev and Maillard (1983). Rapid variations of the standard deviations of continuum counts and H-alpha equivalent widths were not observed. For the continuum counts measurement standard deviations a few hourly variations and two night-to-night variations were found. 16 refs

  10. Modeling Atmospheric Turbulence via Rapid Distortion Theory: Spectral Tensor of Velocity and Buoyancy

    DEFF Research Database (Denmark)

    Chougule, Abhijit S.; Mann, Jakob; Kelly, Mark C.

    2017-01-01

    A spectral tensor model is presented for turbulent fluctuations of wind velocity components and temperature, assuming uniform vertical gradients in mean temperature and mean wind speed. The model is built upon rapid distortion theory (RDT) following studies by Mann and by Hanazaki and Hunt, using...... the eddy lifetime parameterization of Mann to make the model stationary. The buoyant spectral tensor model is driven via five parameters: the viscous dissipation rate epsilon, length scale of energy-containing eddies L, a turbulence anisotropy parameter Gamma, gradient Richardson number (Ri) representing...

  11. Biological removal of iron and manganese in rapid sand filters - Process understanding of iron and manganese removal

    DEFF Research Database (Denmark)

    Lin, Katie

    to precipitation and corrosion. Manganese and iron can either be removed physico-chemically or biologically or combined. The physico-chemical oxidation and precipitation of manganese can theoretically be achieved by aeration, but this process is slow unless pH is raised far above neutral, making the removal...... of manganese by simple aeration and precipitation under normal drinking water treatment conditions insignificant. Manganese may also be oxidized autocatalytically. Iron is usually easier to remove. First, iron is rapidly chemically oxidized by oxygen at neutral pH followed by precipitation and filtration......-filter, where iron is removed. Step 2: Filtration in an after-filter where e.g. ammonium and manganese is removed. The treatment relies on microbial processes and may present an alternative, greener and more sustainable approach for drinking water production spending less chemicals and energy than chemical (e...

  12. Environmental effects of the Big Rapids dam remnant removal, Big Rapids, Michigan, 2000-02

    Science.gov (United States)

    Healy, Denis F.; Rheaume, Stephen J.; Simpson, J. Alan

    2003-01-01

    The U.S. Geological Survey (USGS), in cooperation with the city of Big Rapids, investigated the environmental effects of removal of a dam-foundation remnant and downstream cofferdam from the Muskegon River in Big Rapids, Mich. The USGS applied a multidiscipline approach, which determined the water quality, sediment character, and stream habitat before and after dam removal. Continuous water-quality data and discrete water-quality samples were collected, the movement of suspended and bed sediment were measured, changes in stream habitat were assessed, and streambed elevations were surveyed. Analyses of water upstream and downstream from the dam showed that the dam-foundation remnant did not affect water quality. Dissolved-oxygen concentrations downstream from the dam remnant were depressed for a short period (days) during the beginning of the dam removal, in part because of that removal effort. Sediment transport from July 2000 through March 2002 was 13,800 cubic yards more at the downstream site than the upstream site. This increase in sediment represents the remobilized sediment upstream from the dam, bank erosion when the impoundment was lowered, and contributions from small tributaries between the sites. Five habitat reaches were monitored before and after dam-remnant removal. The reaches consisted of a reference reach (A), upstream from the effects of the impoundment; the impoundment (B); and three sites below the impoundment where habitat changes were expected (C, D, and E, in downstream order). Stream-habitat assessment reaches varied in their responses to the dam-remnant removal. Reference reach A was not affected. In impoundment reach B, Great Lakes and Environmental Assessment Section (GLEAS) Procedure 51 ratings went from fair to excellent. For the three downstream reaches, reach C underwent slight habitat degradation, but ratings remained good; reach D underwent slight habitat degradation with ratings changing from excellent to good; and, in an area

  13. RAPID SPECTRAL CHANGES OF CYGNUS X-1 IN THE LOW/HARD STATE WITH SUZAKU

    Energy Technology Data Exchange (ETDEWEB)

    Yamada, S.; Makishima, K. [Cosmic Radiation Laboratory, Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-0198 (Japan); Negoro, H. [Department of Physics, College of Science and Technology, Nihon University, 1-8 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Torii, S.; Noda, H. [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Mineshige, S. [Department of Astronomy, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan)

    2013-04-20

    Rapid spectral changes in the hard X-ray on a timescale down to {approx}0.1 s are studied by applying a ''shot analysis'' technique to the Suzaku observations of the black hole binary Cygnus X-1, performed on 2008 April 18 during the low/hard state. We successfully obtained the shot profiles, covering 10-200 keV with the Suzaku HXD-PIN and HXD-GSO detector. It is notable that the 100-200 keV shot profile is acquired for the first time owing to the HXD-GSO detector. The intensity changes in a time-symmetric way, though the hardness changes in a time-asymmetric way. When the shot-phase-resolved spectra are quantified with the Compton model, the Compton y-parameter and the electron temperature are found to decrease gradually through the rising phase of the shot, while the optical depth appears to increase. All the parameters return to their time-averaged values immediately within 0.1 s past the shot peak. We have not only confirmed this feature previously found in energies below {approx}60 keV, but also found that the spectral change is more prominent in energies above {approx}100 keV, implying the existence of some instant mechanism for direct entropy production. We discuss possible interpretations of the rapid spectral changes in the hard X-ray band.

  14. Advanced FBG sensing through rapid spectral interrogation

    Science.gov (United States)

    Kunzler, Wesley; Newman, Jason; Wilding, Daniel; Zhu, Zixu; Lowder, Tyson; Selfridge, Richard; Schultz, Stephen; Wirthlin, Michael

    2008-03-01

    A fiber Brag grating sensor interrogator has been developed which is capable of gathering vectors of information from individual fiber Bragg gratings by capturing the full optical spectrum 3 kHz. Using a field programmable gate array with high speed digital-to-analog converters and analog-to-digital components, plus a kilohertz rate MEMS optical filter, the optical spectrum can be scanned at rates in excess of 10 million nanometers per second, allowing sensor sampling rates of many kilohertz while maintaining the necessary resolution to understand sensor changes. The autonomous system design performs all necessary detection and processing of multiple sensors and allows spectral measurements to be exported as fast as Ethernet, USB, or RS232 devices can receive it through a memory mapped interface. The high speed - full spectrum - fiber Bragg grating sensor interrogator enables advanced interrogation of dynamic strain and temperature gradients along the length of a sensor, as well as the use of each sensor for multiple stimuli, such as in temperature compensation. Two examples are described, showing interrogation of rapid laser heating in an optical fiber, as well as complex strain effects in a beam that had an engineered defect.

  15. Microbial pesticide removal in rapid sand filters for drinking water treatment – Potential and kinetics

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen; Albrechtsen, Hans-Jørgen

    2014-01-01

    Filter sand samples, taken from aerobic rapid sand filters used for treating groundwater at three Danish waterworks, were investigated for their pesticide removal potential and to assess the kinetics of the removal process. Microcosms were set up with filter sand, treated water, and the pesticides...... or metabolites mecoprop (MCPP), bentazone, glyphosate and p-nitrophenol were applied in initial concentrations of 0.03–2.4 μg/L. In all the investigated waterworks the concentration of pesticides in the water decreased – MCPP decreased to 42–85%, bentazone to 15–35%, glyphosate to 7–14% and p-nitrophenol 1....../L) increased from 0.21%/g filter sand to 0.75%/g filter sand, when oxygen availability was increased from 0.28 mg O2/g filter sand to 1.09 mg O2/g filter sand. Bentazone was initially cleaved in the removal process. A metabolite, which contained the carbonyl group, was removed rapidly from the water phase...

  16. A Spectral Mapping Signature for the Rapid Ohia Death (ROD Pathogen in Hawaiian Forests

    Directory of Open Access Journals (Sweden)

    Gregory P. Asner

    2018-03-01

    Full Text Available Pathogenic invasions are a major source of change in both agricultural and natural ecosystems. In forests, fungal pathogens can kill habitat-generating plant species such as canopy trees, but methods for remote detection, mapping and monitoring of such outbreaks are poorly developed. Two novel species of the fungal genus Ceratocystis have spread rapidly across humid and mesic forests of Hawaiʻi Island, causing widespread mortality of the keystone endemic canopy tree species, Metrosideros polymorpha (common name: ʻōhiʻa. The process, known as Rapid Ohia Death (ROD, causes browning of canopy leaves in weeks to months following infection by the pathogen. An operational mapping approach is needed to track the spread of the disease. We combined field studies of leaf spectroscopy with laboratory chemical studies and airborne remote sensing to develop a spectral signature for ROD. We found that close to 80% of ROD-infected plants undergo marked decreases in foliar concentrations of chlorophyll, water and non-structural carbohydrates, which collectively result in strong consistent changes in leaf spectral reflectance in the visible (400–700 nm and shortwave-infrared (1300–2500 nm wavelength regions. Leaf-level results were replicated at the canopy level using airborne laser-guided imaging spectroscopy, with quantitative spectral separability of normal green-leaf canopies from suspected ROD-infected brown-leaf canopies in the visible and shortwave-infrared spectrum. Our results provide the spectral–chemical basis for detection, mapping and monitoring of the spread of ROD in native Hawaiian forests.

  17. Removal of Optically Thick Clouds from Multi-Spectral Satellite Images Using Multi-Frequency SAR Data

    Directory of Open Access Journals (Sweden)

    Robert Eckardt

    2013-06-01

    Full Text Available This study presents a method for the reconstruction of pixels contaminated by optical thick clouds in multi-spectral Landsat images using multi-frequency SAR data. A number of reconstruction techniques have already been proposed in the scientific literature. However, all of the existing techniques have certain limitations. In order to overcome these limitations, we expose the Closest Spectral Fit (CSF method proposed by Meng et al. to a new, synergistic approach using optical and SAR data. Therefore, the term Closest Feature Vector (CFV is introduced. The technique facilitates an elegant way to avoid radiometric distortions in the course of image reconstruction. Furthermore the cloud cover removal is independent from underlying land cover types and assumptions on seasonality, etc. The methodology is applied to mono-temporal, multi-frequency SAR data from TerraSAR-X (X-Band, ERS (C-Band and ALOS Palsar (L-Band. This represents a way of thinking about Radar data not as foreign, but as additional data source in multi-spectral remote sensing. For the assessment of the image restoration performance, an experimental framework is established and a statistical evaluation protocol is designed. The results show the potential of a synergistic usage of multi-spectral and SAR data to overcome the loss of data due to cloud cover.

  18. Evaluate of head loss, sediment value and copper removal in sand media (rapid sand filter

    Directory of Open Access Journals (Sweden)

    Daneshi Navab

    2014-06-01

    Full Text Available Along with the technology development and increasing consumption of water resources, we are experiencing low qualities in the mentioned resources. Copper brings about serious environment al pollution, threatening human health and ecosystem. This metal found variously in water resources and industrial activities. Therefore, it needs to treat the water resources from these excessive amounts. Different methods have used for this reason but the most used method during recent years has been the absorption by economic absorbers such as sand. Rapid sand filters usually used in water and wastewater treatment plants for water clarification. In this research, a single layer gravity rapid sand filter has used to reduce different concentrations of copper. sediment value and head loss arising in filter media is simulated by using combination of Carman-Kozeny, Rose and Gregory models in different discharges of rapid sand filter. Results have shown that with increasing in discharge and decreasing in input copper concentration, arriving time to given head loss, is increasing. In addition, results demonstrated that with increasing in copper concentration in influent, removal efficiency is decreasing somewhat. Results of this research can applied in an appropriate design of rapid sand filter to copper removal, a prediction of rapid sand filter ability to copper removal and an estimation of arising head loss during filter work thus evaluating of time interval backwash. DOI: http://dx.doi.org/10.3126/ije.v3i2.10641 International Journal of the Environment Vol.3(2 2014: 276-286

  19. RAPID MONITORING BY QPCR FOR PATHOGENIC ASPERGILLUS DURING CARPET REMOVAL FROM A HOSPITAL

    Science.gov (United States)

    Monitoring for pathogenic Aspergillus species using a rapid, highly sensitive, quantitative polymerase chain reaction technique during carpet removal in a burn unit provided data which allowed the patients to be safely returned to the re-floored area sooner than if only conventi...

  20. Removal of turbidity and suspended solids backwash water from rapid sand filter by using electrocoagulation

    Directory of Open Access Journals (Sweden)

    AR Yari

    2016-07-01

    Full Text Available Introduction: By appropriate method can be recycled more than 95 percent effluent backwashing the filter. This study aimed to examine the efficiency of the electrocoagulation process on turbidity and suspended solids removal from backwash effluent of rapid sand filter of water treatment plants No 1 in Karaj. Methods: This bench-scale experimental study was carried out on the samples of backwash effluent in a batch system. The Plexiglas tank with a volume of 4 liters, containing of 4 plate electrodes made of aluminum and iron was connected to a direct current power supply. Samples every 15 minutes to measure turbidity and suspended solids collected in the middle of the reactor and examined. Effect of several parameters such as current density, reaction time and voltage were studied. The total number of samples tested were 48. Turbidity and total suspended solids was measured by nephlometry and gravimetric method, respectively. Results: The highest removal efficiency of turbidity and suspended solids in reaction time of 60 minutes, current density of 2 mA and a voltage of 45 mV was observed. The highest removal efficiency of turbidity in aluminum and iron electrodes were 96.83 and 83.77 %, respectively. Also The highest removal efficiency of suspended solids were 96.73 and 86.22 %, respectively. Conclusion: The results showed that electro- coagulation process can be a good choice to remove turbidity and suspended from backwash of rapid sand filter. Aluminum electrode efficiency in the removal of turbidity and suspended solids was greater than the iron electrode.

  1. Rapid detection of chlorpyrifos pesticide residue concentration in agro-product using Raman spectroscopy

    Science.gov (United States)

    Dhakal, Sagar; Peng, Yankun; Li, Yongyu; Chao, Kuanglin; Qin, Jianwei; Zhang, Leilei; Xu, Tianfeng

    2014-05-01

    Different chemicals are sprayed in fruits and vegetables before and after harvest for better yield and longer shelf-life of crops. Cases of pesticide poisoning to human health are regularly reported due to excessive application of such chemicals for greater economic benefit. Different analytical technologies exist to detect trace amount of pesticides in fruits and vegetables, but are expensive, sample destructive, and require longer processing time. This study explores the application of Raman spectroscopy for rapid and non-destructive detection of pesticide residue in agricultural products. Raman spectroscopy with laser module of 785 nm was used to collect Raman spectral information from the surface of Gala apples contaminated with different concentrations of commercially available organophosphorous (48% chlorpyrifos) pesticide. Apples within 15 days of harvest from same orchard were used in this study. The Raman spectral signal was processed by Savitzky-Golay (SG) filter for noise removal, Multiplicative Scatter Correction (MSC) for drift removal and finally polynomial fitting was used to eliminate the fluorescence background. The Raman spectral peak at 677 cm-1 was recognized as Raman fingerprint of chlorpyrifos. Presence of Raman peak at 677 cm-1 after fluorescence background removal was used to develop classification model (presence and absence of pesticide). The peak intensity was correlated with actual pesticide concentration obtained using Gas Chromatography and MLR prediction model was developed with correlation coefficient of calibration and validation of 0.86 and 0.81 respectively. Result shows that Raman spectroscopy is a promising tool for rapid, real-time and non-destructive detection of pesticide residue in agro-products.

  2. Rapid estimation of compost enzymatic activity by spectral analysis method combined with machine learning.

    Science.gov (United States)

    Chakraborty, Somsubhra; Das, Bhabani S; Ali, Md Nasim; Li, Bin; Sarathjith, M C; Majumdar, K; Ray, D P

    2014-03-01

    The aim of this study was to investigate the feasibility of using visible near-infrared (VisNIR) diffuse reflectance spectroscopy (DRS) as an easy, inexpensive, and rapid method to predict compost enzymatic activity, which traditionally measured by fluorescein diacetate hydrolysis (FDA-HR) assay. Compost samples representative of five different compost facilities were scanned by DRS, and the raw reflectance spectra were preprocessed using seven spectral transformations for predicting compost FDA-HR with six multivariate algorithms. Although principal component analysis for all spectral pretreatments satisfactorily identified the clusters by compost types, it could not separate different FDA contents. Furthermore, the artificial neural network multilayer perceptron (residual prediction deviation=3.2, validation r(2)=0.91 and RMSE=13.38 μg g(-1) h(-1)) outperformed other multivariate models to capture the highly non-linear relationships between compost enzymatic activity and VisNIR reflectance spectra after Savitzky-Golay first derivative pretreatment. This work demonstrates the efficiency of VisNIR DRS for predicting compost enzymatic as well as microbial activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. The FIR-Radio Correlation in Rapidly Star-Forming Galaxies: The Spectral Index Problem and Proton Calorimetry

    Science.gov (United States)

    Thompson, Todd A.; Lacki, Brian C.

    We review the physics of the FIR-radio correlation (FRC) of star-forming galaxies, focusing on "electron calorimetry" as an explanation. We emphasize the importance of the "spectral index problem"—that galaxies have flatter GHz synchrotron spectra than predicted in the strong-cooling calorimeter limit. We argue that these shallow spectra require significant bremsstrahlung and/or ionization losses for the primary and secondary CR electron/positron populations. This then implies that CR protons suffer strong pionic losses before escape in dense starburst galaxies ("proton calorimetry"), and that these systems should be gamma-ray bright, forming a FIR-gamma-ray correlation. Implications for the diffuse non-thermal cosmic gamma-ray and neutrino backgrounds are mentioned. Caveats and uncertainties, as well as other solutions to the "spectral index problem" such as rapid advection of CRs in starburst superwinds, are highlighted.

  4. Intensity Conserving Spectral Fitting

    Science.gov (United States)

    Klimchuk, J. A.; Patsourakos, S.; Tripathi, D.

    2015-01-01

    The detailed shapes of spectral line profiles provide valuable information about the emitting plasma, especially when the plasma contains an unresolved mixture of velocities, temperatures, and densities. As a result of finite spectral resolution, the intensity measured by a spectrometer is the average intensity across a wavelength bin of non-zero size. It is assigned to the wavelength position at the center of the bin. However, the actual intensity at that discrete position will be different if the profile is curved, as it invariably is. Standard fitting routines (spline, Gaussian, etc.) do not account for this difference, and this can result in significant errors when making sensitive measurements. Detection of asymmetries in solar coronal emission lines is one example. Removal of line blends is another. We have developed an iterative procedure that corrects for this effect. It can be used with any fitting function, but we employ a cubic spline in a new analysis routine called Intensity Conserving Spline Interpolation (ICSI). As the name implies, it conserves the observed intensity within each wavelength bin, which ordinary fits do not. Given the rapid convergence, speed of computation, and ease of use, we suggest that ICSI be made a standard component of the processing pipeline for spectroscopic data.

  5. Using a Spectral Method to Evaluate Hyporheic Exchange and its Effect on Reach Scale Nitrate Removal.

    Science.gov (United States)

    Moren, I.; Worman, A. L. E.; Riml, J.

    2017-12-01

    Previous studies have shown that hyporheic exchange processes can be of great importance for the transport, retention and mass removal of nutrients in streams. Specifically, the flow of surface water through the hyporheic zone enhances redox-sensitive reactions such as coupled nitrification-denitrification. This self-cleaning capacity of streams can be utilized in stream restoration projects aiming to improve water quality by reconstructing the geomorphology of the streams. To optimize the effect of restoration actions we need quantitative understanding of the linkage between stream geomorphology, hyporheic exchange processes and the desired water quality targets. Here we propose an analytical, spectral methodology to evaluate how different stream geomorphologies induce hyporheic exchange on a wide range of spatial and temporal scales. Measurements of streambed topographies and surface water profiles from agricultural streams were used to calculate the average hyporheic exchange velocity and residence times and the result was compared with in-stream tracer test. Furthermore, the hyporheic exchange induced by steps in the surface water profile was derived as a comparison of the theoretical capacity of the system. Based on differences in hyporheic exchange, the mass removal of nitrate could be derived for the different geomorphologies. The maximum nitrate mass removal was found to be related to a specific Damkhöler number, which reflects that the mass removal can be either reaction or transport controlled. Therefore, although hyporheic exchange induced by steps in the surface water profile was generally larger than the hyporheic exchange in the observed natural reaches, this would not necessarily lead a larger nitrate mass removal provided that the hyporheic residence times are not long enough to facilitate denitrification processes. The study illustrates the importance to investigate a stream thoroughly before any remediation actions are implemented, specifically

  6. Development of a Rapid and Simple Method to Remove Polyphenols from Plant Extracts

    Directory of Open Access Journals (Sweden)

    Imali Ranatunge

    2017-01-01

    Full Text Available Polyphenols are secondary metabolites of plants, which are responsible for prevention of many diseases. Polyvinylpolypyrrolidone (PVPP has a high affinity towards polyphenols. This method involves the use of PVPP column to remove polyphenols under centrifugal force. Standards of gallic acid, epigallocatechin gallate, vanillin, and tea extracts (Camellia sinensis were used in this study. PVPP powder was packed in a syringe with different quantities. The test samples were layered over the PVPP column and subjected to centrifugation. Supernatant was tested for the total phenol content. The presence of phenolic compounds and caffeine was screened by HPLC and measuring the absorbance at 280. The antioxidant capacity of standards and tea extracts was compared with the polyphenol removed fractions using DPPH scavenging assay. No polyphenols were found in polyphenolic standards or tea extracts after PVPP treatment. The method described in the present study to remove polyphenols is simple, inexpensive, rapid, and efficient and can be employed to investigate the contribution of polyphenols present in natural products to their biological activity.

  7. RAPID MONITORING BY QUANTITATIVE POLYMERASE CHAIN REACTION FOR PATHOGENIC ASPERGILLUS DURING CARPET REMOVAL FROM A HOSPITAL

    Science.gov (United States)

    Monitoring for pathogenic Aspergillus species using a rapid, highly sensitive, quantitative polumerase chain reaction technique during carpet removal in a burn unit provided data which allowed the patients to be safely returned to the re-floored area sooner than if only conventio...

  8. Rectangular spectral collocation

    KAUST Repository

    Driscoll, Tobin A.; Hale, Nicholas

    2015-01-01

    Boundary conditions in spectral collocation methods are typically imposed by removing some rows of the discretized differential operator and replacing them with others that enforce the required conditions at the boundary. A new approach based upon

  9. Rapid simulation of spatial epidemics: a spectral method.

    Science.gov (United States)

    Brand, Samuel P C; Tildesley, Michael J; Keeling, Matthew J

    2015-04-07

    Spatial structure and hence the spatial position of host populations plays a vital role in the spread of infection. In the majority of situations, it is only possible to predict the spatial spread of infection using simulation models, which can be computationally demanding especially for large population sizes. Here we develop an approximation method that vastly reduces this computational burden. We assume that the transmission rates between individuals or sub-populations are determined by a spatial transmission kernel. This kernel is assumed to be isotropic, such that the transmission rate is simply a function of the distance between susceptible and infectious individuals; as such this provides the ideal mechanism for modelling localised transmission in a spatial environment. We show that the spatial force of infection acting on all susceptibles can be represented as a spatial convolution between the transmission kernel and a spatially extended 'image' of the infection state. This representation allows the rapid calculation of stochastic rates of infection using fast-Fourier transform (FFT) routines, which greatly improves the computational efficiency of spatial simulations. We demonstrate the efficiency and accuracy of this fast spectral rate recalculation (FSR) method with two examples: an idealised scenario simulating an SIR-type epidemic outbreak amongst N habitats distributed across a two-dimensional plane; the spread of infection between US cattle farms, illustrating that the FSR method makes continental-scale outbreak forecasting feasible with desktop processing power. The latter model demonstrates which areas of the US are at consistently high risk for cattle-infections, although predictions of epidemic size are highly dependent on assumptions about the tail of the transmission kernel. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Rapid startup and high rate nitrogen removal from anaerobic sludge digester liquor using a SNAP process.

    Science.gov (United States)

    Qiao, Sen; Nishiyama, Takashi; Fujii, Tatsuo; Bhatti, Zafar; Furukawa, Kenji

    2012-02-01

    In this study, a single-stage autotrophic nitrogen removal reactor, packed with a novel acrylic fiber biomass carrier material (Biofix), was applied for nitrogen removal from sludge digester liquor. For rapid start-up, conventional activated sludge was added to the reactor soon after the attachment of anammox biomass on the Biofix carriers, which allowed conventional activated sludge to form a protective layer of biofilm around the anammox biomass. The Nitrogen removal efficiency reached 75% within 1 week at a nitrogen loading rate of 0.46 kg-N/m(3)/day for synthetic wastewater treatment. By the end of the synthetic wastewater treatment period, the maximum nitrogen removal rate had increased to 0.92 kg-N/m(3)/day at a nitrogen loading rate of 1.0 kg-N/m(3)/day. High nitrogen removal rate was also achieved during the actual raw digester liquor treatment with the highest nitrogen removal rate being 0.83 kg-N/m(3)/day at a nitrogen loading rate of 0.93 kg-N/m(3)/day. The thick biofilm on Biofix carriers allowed anammox bacteria to survive under high DO concentration of 5-6 mg/l resulting in stable and high nitrogen removal performance. FISH and CLSM analysis demonstrated that anammox bacteria coexisted and surrounded by ammonium oxidizing bacteria.

  11. Rapid Removal of Tetrabromobisphenol A by Ozonation in Water: Oxidation Products, Reaction Pathways and Toxicity Assessment.

    Directory of Open Access Journals (Sweden)

    Ruijuan Qu

    Full Text Available Tetrabromobisphenol A (TBBPA is one of the most widely used brominated flame retardants and has attracted more and more attention. In this work, the parent TBBPA with an initial concentration of 100 mg/L was completely removed after 6 min of ozonation at pH 8.0, and alkaline conditions favored a more rapid removal than acidic and neutral conditions. The presence of typical anions and humic acid did not significantly affect the degradation of TBBPA. The quenching test using isopropanol indicated that direct ozone oxidation played a dominant role during this process. Seventeen reaction intermediates and products were identified using an electrospray time-of-flight mass spectrometer. Notably, the generation of 2,4,6-tribromophenol was first observed in the degradation process of TBBPA. The evolution of reaction products showed that ozonation is an efficient treatment for removal of both TBBPA and intermediates. Sequential transformation of organic bromine to bromide and bromate was confirmed by ion chromatography analysis. Two primary reaction pathways that involve cleavage of central carbon atom and benzene ring cleavage concomitant with debromination were thus proposed and further justified by calculations of frontier electron densities. Furthermore, the total organic carbon data suggested a low mineralization rate, even after the complete removal of TBBPA. Meanwhile, the acute aqueous toxicity of reaction solutions to Photobacterium Phosphoreum and Daphnia magna was rapidly decreased during ozonation. In addition, no obvious difference in the attenuation of TBBPA was found by ozone oxidation using different water matrices, and the effectiveness in natural waters further demonstrates that ozonation can be adopted as a promising technique to treat TBBPA-contaminated waters.

  12. Rapid Removal of Tetrabromobisphenol A by Ozonation in Water: Oxidation Products, Reaction Pathways and Toxicity Assessment

    Science.gov (United States)

    Wang, Xinghao; Huang, Qingguo; Lu, Junhe; Wang, Liansheng; Wang, Zunyao

    2015-01-01

    Tetrabromobisphenol A (TBBPA) is one of the most widely used brominated flame retardants and has attracted more and more attention. In this work, the parent TBBPA with an initial concentration of 100 mg/L was completely removed after 6 min of ozonation at pH 8.0, and alkaline conditions favored a more rapid removal than acidic and neutral conditions. The presence of typical anions and humic acid did not significantly affect the degradation of TBBPA. The quenching test using isopropanol indicated that direct ozone oxidation played a dominant role during this process. Seventeen reaction intermediates and products were identified using an electrospray time-of-flight mass spectrometer. Notably, the generation of 2,4,6-tribromophenol was first observed in the degradation process of TBBPA. The evolution of reaction products showed that ozonation is an efficient treatment for removal of both TBBPA and intermediates. Sequential transformation of organic bromine to bromide and bromate was confirmed by ion chromatography analysis. Two primary reaction pathways that involve cleavage of central carbon atom and benzene ring cleavage concomitant with debromination were thus proposed and further justified by calculations of frontier electron densities. Furthermore, the total organic carbon data suggested a low mineralization rate, even after the complete removal of TBBPA. Meanwhile, the acute aqueous toxicity of reaction solutions to Photobacterium Phosphoreum and Daphnia magna was rapidly decreased during ozonation. In addition, no obvious difference in the attenuation of TBBPA was found by ozone oxidation using different water matrices, and the effectiveness in natural waters further demonstrates that ozonation can be adopted as a promising technique to treat TBBPA-contaminated waters. PMID:26430733

  13. Preparation and performance study of MgFe2O4/metal-organic framework composite for rapid removal of organic dyes from water

    Science.gov (United States)

    Tian, Huairu; Peng, Jun; Lv, Tingting; Sun, Chen; He, Hua

    2018-01-01

    In present study, a stable and magnetic metal-organic framework (MOF) material was synthesized by simple solvothermal method as adsorbent to rapid removal of two organic dyes, the Rhodamine B (RB) and Rhodamine 6G (Rh6G), in water samples. The prepared material showed great characteristics of large surface area (519.86 m2 g-1), excellent magnetic responsivity (35.00 emu g-1) and rapid removal (within 5 min). Maximum adsorption capacities of the magnetic material toward RB and Rh6G were up to 219.78 and 306.75 mg g-1, respectively. Adsorption kinetics suggested the adsorption process met the pseudo-second-order kinetic model. The prepared material could be reused at least 10 times by washing with acetonitrile solution, the relative standard deviation (RSD) of these ten cycles removal efficiency was 4.8%. In conclusion, good chemical inertness, a mechanical/water stability and super-hydrophilicity feature made this MOF a promising adsorbent for targets removal from environmental water sample.

  14. Firefighter Down! How to Rapidly Remove Turnout Gear.

    Science.gov (United States)

    ALexander, John G

    2016-04-01

    The rescue of an injured colleague--and probably a good friend--is an emotionally charged event. A common initial response could be to remove everything as quickly as possible. Keep in mind that we have accepted practices for the removal of motorcycle equipment and football gear. There are also procedures for removing a patient from a vehicle or swimming pool. These all exist to protect a patient from further injury. We now have established practices for removing a firefighter from a window, or down a ladder. Why then do the procedures stop? Once a firefighter is rescued from a hot zone, he deserves the same level of consideration a football player, motorcycle rider or any other patient receives. We should not be in such a hurry that we don't care how we remove a protective ensemble. The injured firefighter deserves a system, or a procedure, that may be practiced by others and reduce the chance of further injury during

  15. MALDI-TOF Baseline Drift Removal Using Stochastic Bernstein Approximation

    Directory of Open Access Journals (Sweden)

    Howard Daniel

    2006-01-01

    Full Text Available Stochastic Bernstein (SB approximation can tackle the problem of baseline drift correction of instrumentation data. This is demonstrated for spectral data: matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF data. Two SB schemes for removing the baseline drift are presented: iterative and direct. Following an explanation of the origin of the MALDI-TOF baseline drift that sheds light on the inherent difficulty of its removal by chemical means, SB baseline drift removal is illustrated for both proteomics and genomics MALDI-TOF data sets. SB is an elegant signal processing method to obtain a numerically straightforward baseline shift removal method as it includes a free parameter that can be optimized for different baseline drift removal applications. Therefore, research that determines putative biomarkers from the spectral data might benefit from a sensitivity analysis to the underlying spectral measurement that is made possible by varying the SB free parameter. This can be manually tuned (for constant or tuned with evolutionary computation (for .

  16. RAMBO-K: Rapid and Sensitive Removal of Background Sequences from Next Generation Sequencing Data.

    Directory of Open Access Journals (Sweden)

    Simon H Tausch

    Full Text Available The assembly of viral or endosymbiont genomes from Next Generation Sequencing (NGS data is often hampered by the predominant abundance of reads originating from the host organism. These reads increase the memory and CPU time usage of the assembler and can lead to misassemblies.We developed RAMBO-K (Read Assignment Method Based On K-mers, a tool which allows rapid and sensitive removal of unwanted host sequences from NGS datasets. Reaching a speed of 10 Megabases/s on 4 CPU cores and a standard hard drive, RAMBO-K is faster than any tool we tested, while showing a consistently high sensitivity and specificity across different datasets.RAMBO-K rapidly and reliably separates reads from different species without data preprocessing. It is suitable as a straightforward standard solution for workflows dealing with mixed datasets. Binaries and source code (java and python are available from http://sourceforge.net/projects/rambok/.

  17. Rapid removal of fine particles from mine water using sequential processes of coagulation and flocculation.

    Science.gov (United States)

    Jang, Min; Lee, Hyun-Ju; Shim, Yonsik

    2010-04-01

    The processes of coagulation and flocculation using high molecular weight long-chain polymers were applied to treat mine water having fine flocs of which about 93% of the total mass was less than 3.02 microm, representing the size distribution of fine particles. Six different combinations of acryl-type anionic flocculants and polyamine-type cationic coagulants were selected to conduct kinetic tests on turbidity removal in mine water. Optimization studies on the types and concentrations of the coagulant and flocculant showed that the highest rate of turbidity removal was obtained with 10 mg L(-1) FL-2949 (coagulant) and 12 mg L(-1) A333E (flocculant), which was about 14.4 and 866.7 times higher than that obtained with A333E alone and that obtained through natural precipitation by gravity, respectively. With this optimized condition, the turbidity of mine water was reduced to 0 NTU within 20 min. Zeta potential measurements were conducted to elucidate the removal mechanism of the fine particles, and they revealed that there was a strong linear relationship between the removal rate of each pair of coagulant and flocculant application and the zeta potential differences that were obtained by subtracting the zeta potential of flocculant-treated mine water from the zeta potential of coagulant-treated mine water. Accordingly, through an optimization process, coagulation-flocculation by use of polymers could be advantageous to mine water treatment, because the process rapidly removes fine particles in mine water and only requires a small-scale plant for set-up purposes owing to the short retention time in the process.

  18. Spin-Label CW Microwave Power Saturation and Rapid Passage with Triangular Non-Adiabatic Rapid Sweep (NARS) and Adiabatic Rapid Passage (ARP) EPR Spectroscopy

    Science.gov (United States)

    Kittell, Aaron W.; Hyde, James S.

    2015-01-01

    Non-adiabatic rapid passage (NARS) electron paramagnetic resonance (EPR) spectroscopy was introduced by Kittell, A.W., Camenisch, T.G., Ratke, J.J. Sidabras, J.W., Hyde, J.S., 2011 as a general purpose technique to collect the pure absorption response. The technique has been used to improve sensitivity relative to sinusoidal magnetic field modulation, increase the range of inter-spin distances that can be measured under near physiological conditions, and enhance spectral resolution in copper (II) spectra. In the present work, the method is extended to CW microwave power saturation of spin-labeled T4 Lysozyme (T4L). As in the cited papers, rapid triangular sweep of the polarizing magnetic field was superimposed on slow sweep across the spectrum. Adiabatic rapid passage (ARP) effects were encountered in samples undergoing very slow rotational diffusion as the triangular magnetic field sweep rate was increased. The paper reports results of variation of experimental parameters at the interface of adiabatic and non-adiabatic rapid sweep conditions. Comparison of the forward (up) and reverse (down) triangular sweeps is shown to be a good indicator of the presence of rapid passage effects. Spectral turning points can be distinguished from spectral regions between turning points in two ways: differential microwave power saturation and differential passage effects. Oxygen accessibility data are shown under NARS conditions that appear similar to conventional field modulation data. However, the sensitivity is much higher, permitting, in principle, experiments at substantially lower protein concentrations. Spectral displays were obtained that appear sensitive to rotational diffusion in the range of rotational correlation times of 10−3 to 10−7 s in a manner that is analogous to saturation transfer spectroscopy. PMID:25917132

  19. SPRAT: Spectrograph for the Rapid Acquisition of Transients

    Science.gov (United States)

    Piascik, A. S.; Steele, Iain A.; Bates, Stuart D.; Mottram, Christopher J.; Smith, R. J.; Barnsley, R. M.; Bolton, B.

    2014-07-01

    We describe the development of a low cost, low resolution (R ~ 350), high throughput, long slit spectrograph covering visible (4000-8000) wavelengths. The spectrograph has been developed for fully robotic operation with the Liverpool Telescope (La Palma). The primary aim is to provide rapid spectral classification of faint (V ˜ 20) transient objects detected by projects such as Gaia, iPTF (intermediate Palomar Transient Factory), LOFAR, and a variety of high energy satellites. The design employs a volume phase holographic (VPH) transmission grating as the dispersive element combined with a prism pair (grism) in a linear optical path. One of two peak spectral sensitivities are selectable by rotating the grism. The VPH and prism combination and entrance slit are deployable, and when removed from the beam allow the collimator/camera pair to re-image the target field onto the detector. This mode of operation provides automatic acquisition of the target onto the slit prior to spectrographic observation through World Coordinate System fitting. The selection and characterisation of optical components to maximise photon throughput is described together with performance predictions.

  20. APTES Functionalized Iron Oxide-Silver Magnetic Hetero-Nanocomposites for Selective Capture and Rapid Removal of Salmonella enteritidis from Aqueous Solution

    Science.gov (United States)

    Trang, Vu Thi; Dinh, Ngo Xuan; Lan, Hoang; Tam, Le Thi; Huy, Tran Quang; Tuan, Pham Anh; Phan, Vu Ngoc; Le, Anh-Tuan

    2018-02-01

    Magnetic nanomaterials, as a promising platform for the fast and sensitive detection of bacterial pathogens, have attracted increasing interest from researchers in recent years. In this work, by utilizing a two-step synthetic technique consisting of co-precipitation and subsequent hydrothermal reaction, followed by functionalization steps with (3-aminopropyl)triethoxysilane (APTES) and the antibody against Salmonella enteritidis, antibody-conjugated Fe3O4-Ag@APTES hetero-nanocomposites were successfully prepared. Due to the specific antibody, the developed Fe3O4-Ag@APTES@SE-Ab conjugates are capable of selectively capturing S. enteritidis at a low concentration of about 101 CFU/mL. Moreover, the prepared magnetic conjugates also revealed that the S. enteritidis could be rapidly removed from water solution in 20 min by using an external magnetic field with a removal efficiency obtained of ˜ 91.36%. These results indicated that the Fe3O4-Ag@APTES@SE-Ab conjugates are promising for the rapid selective capture and removal of bacterial pathogens from aqueous environments, and can be used for improving the detection quality of pathogens in water samples using immunosensor-based diagnostic tests.

  1. Rapid removal of fine particles from mine water using sequential processes of coagulation and flocculation

    Energy Technology Data Exchange (ETDEWEB)

    Jang, M.; Lee, H.J.; Shim, Y. [Korean Mine Reclamation Corporation MIRECO, Seoul (Republic of Korea)

    2010-07-01

    The processes of coagulation and flocculation using high molecular weight long-chain polymers were applied to treat mine water having fine flocs of which about 93% of the total mass was less than 3.02 {mu} m, representing the size distribution of fine particles. Six different combinations of acryl-type anionic flocculants and polyamine-type cationic coagulants were selected to conduct kinetic tests on turbidity removal in mine water. Optimization studies on the types and concentrations of the coagulant and flocculant showed that the highest rate of turbidity removal was obtained with 10 mg L{sup -1} FL-2949 (coagulant) and 12 mg L{sup -1} A333E (flocculant), which was about 14.4 and 866.7 times higher than that obtained with A333E alone and that obtained through natural precipitation by gravity, respectively. With this optimized condition, the turbidity of mine water was reduced to 0 NTU within 20 min. Zeta potential measurements were conducted to elucidate the removal mechanism of the fine particles, and they revealed that there was a strong linear relationship between the removal rate of each pair of coagulant and flocculant application and the zeta potential differences that were obtained by subtracting the zeta potential of flocculant-treated mine water from the zeta potential of coagulant-treated mine water. Accordingly, through an optimization process, coagulation-flocculation by use of polymers could be advantageous to mine water treatment, because the process rapidly removes fine particles in mine water and only requires a small-scale plant for set-up purposes owing to the short retention time in the process.

  2. Rapid spectral and flux time variations in a solar burst observed at various dm-mm wavelengths and at hard x rays

    International Nuclear Information System (INIS)

    Zodivaz, A.M.; Kaufmann, P.; Correia, E.; Costa, J.E.R.; Takakura, T.; Cliver, E.W.; Tapping, K.F.; Air Force Geophysics Lab., Hanscom AFB, MA; National Research Council of Canada, Ottawa, Ontario)

    1986-01-01

    A solar burst was observed with high sensitivity and time resolution at cm-mm wavelengths by two different radio observatories (Itapetinga and Algonquin), with high spectral time resolution at dm-mm wavelengths by patrol instruments (Sagamore Hill), and at hard x rays (HXM Hinotori). At the onset of the major burst time structure there was a rapid rise in the spectral turnover frequency (from 5 to 15 GHz), in about 10s, coincident to a reduction of the spectral index in the optically thin part of the spectrum. The burst maxima were not time coincident at the optically thin radio frequencies and at the different hard x ray energy ranges. The profiles at higher radio frequencies exhibited better time coincidence to the high energy x rays. The hardest x ray spectrum (-3) coincided with peak radio emission at the higher frequency (44 GHz). The event appeared to be built up by a first major injection of softer particles followed by other injections of harder particles. Ultrafast time structures were identified as superimposed on the burst emission at the cm-mm high sensitivity data at x rays, with predominant repetition rates ranging from 2.0 to 3.5 Hz

  3. Spectral evolution of galaxies: current views

    International Nuclear Information System (INIS)

    Bruzual, A.G.

    1985-01-01

    A summary of current views on the interpretation of the various evolutionary tests aimed at detecting spectral evolution in galaxies is presented. It is concluded that the evolution taking place in known galaxy samples is a slow process (perhaps consistent with no evolution at all), and that the early phases of rapid spectral evolution in early-type galaxies have not yet been detected. (author)

  4. Spectral Imaging Technology-Based Evaluation of Radiation Treatment Planning to Remove Contrast Agent Artifacts.

    Science.gov (United States)

    Yi-Qun, Xu; Wei, Liu; Xin-Ye, Ni

    2016-10-01

    This study employs dual-source computed tomography single-spectrum imaging to evaluate the effects of contrast agent artifact removal and the computational accuracy of radiotherapy treatment planning improvement. The phantom, including the contrast agent, was used in all experiments. The amounts of iodine in the contrast agent were 30, 15, 7.5, and 0.75 g/100 mL. Two images with different energy values were scanned and captured using dual-source computed tomography (80 and 140 kV). To obtain a fused image, 2 groups of images were processed using single-energy spectrum imaging technology. The Pinnacle planning system was used to measure the computed tomography values of the contrast agent and the surrounding phantom tissue. The difference between radiotherapy treatment planning based on 80 kV, 140 kV, and energy spectrum image was analyzed. For the image with high iodine concentration, the quality of the energy spectrum-fused image was the highest, followed by that of the 140-kV image. That of the 80-kV image was the worst. The difference in the radiotherapy treatment results among the 3 models was significant. When the concentration of iodine was 30 g/100 mL and the distance from the contrast agent at the dose measurement point was 1 cm, the deviation values (P) were 5.95% and 2.20% when image treatment planning was based on 80 and 140 kV, respectively. When the concentration of iodine was 15 g/100 mL, deviation values (P) were -2.64% and -1.69%. Dual-source computed tomography single-energy spectral imaging technology can remove contrast agent artifacts to improve the calculated dose accuracy in radiotherapy treatment planning. © The Author(s) 2015.

  5. Rapid Chemometric X-Ray Fluorescence approaches for spectral Diagnostics of Cancer utilizing Tissue Trace Metals and Speciation profiles

    International Nuclear Information System (INIS)

    Okonda, J.J.

    2015-01-01

    Energy dispersive X-ray fluorescence (EDXRF) spectroscopy is an analytical method for identification and quantification of elements in materials by measurement of their spectral energy and intensity. EDXRFS spectroscopic technique involves simultaneous non-invasive acquisition of both fluorescence and scatter spectra from samples for quantitative determination of trace elemental content in complex matrix materials. The objective is develop a chemometric-aided EDXRFS method for rapid diagnosis of cancer and its severity (staging) based on analysis of trace elements (Cu, Zn, Fe, Se and Mn), their speciation and multivariate alterations of the elements in cancerous body tissue samples as cancer biomarkers. The quest for early diagnosis of cancer is based on the fact that early intervention translates to higher survival rate and better quality of life. Chemometric aided EDXRFS cancer diagnostic model has been evaluated as a direct and rapid superior alternative for the traditional quantitative methods used in XRF such as FP method. PCA results of cultured samples indicate that it is possible to characterize cancer at early and late stage of development based on trace elemental profiles

  6. Rapid startup of thermophilic anaerobic digester to remove tetracycline and sulfonamides resistance genes from sewage sludge.

    Science.gov (United States)

    Xu, Rui; Yang, Zhao-Hui; Wang, Qing-Peng; Bai, Yang; Liu, Jian-Bo; Zheng, Yue; Zhang, Yan-Ru; Xiong, Wei-Ping; Ahmad, Kito; Fan, Chang-Zheng

    2018-01-15

    Spread of antibiotic resistance genes (ARGs) originating from sewage sludge is highlighted as an eminent health threat. This study established a thermophilic anaerobic digester using one-step startup strategy to quickly remove tetracycline and sulfonamides resistance genes from sewage sludge. At least 20days were saved in the startup period from mesophilic to thermophilic condition. Based on the results of 16S rDNA amplicons sequencing and predicted metagenomic method, the successful startup largely relied on the fast colonization of core thermophilic microbial population (e.g. Firmicutes, Proteobacteria, Actinobacteria). Microbial metabolic gene pathways for substrate degradation and methane production was also increased by one-step mode. In addition, real-time quantitative PCR approach revealed that most targeted tetracycline and sulfonamides resistance genes ARGs (sulI, tetA, tetO, tetX) were substantially removed during thermophilic digestion (removal efficiency>80%). Network analysis showed that the elimination of ARGs was attributed to the decline of their horizontal (intI1 item) and vertical (potential hosts) transfer-related elements under high-temperature. This research demonstrated that rapid startup thermophilic anaerobic digestion of wastewater solids would be a suitable technology for reducing quantities of various ARGs. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Improved Electrocoagulation Reactor for Rapid Removal of Phosphate from Wastewater

    KAUST Repository

    Tian, Yushi

    2016-11-01

    A new three-electrode electrocoagulation reactor was investigated to increase the rate of removal of phosphate from domestic wastewater. Initially, two electrodes (graphite plate and air cathode) were connected with 0.5 V of voltage applied for a short charging time (∼10 s). The direction of the electric field was then reversed, by switching the power supply lead from the anode to the cathode, and connecting the other lead to a sacrificial aluminum mesh anode for removal of phosphate by electrocoagulation. The performance of this process, called a reverse-electric field, air cathode electrocoagulation (REAEC) reactor, was tested using domestic wastewater as a function of charging time and electrocoagulation time. REAEC wastewater treatment removed up to 98% of phosphate in 15 min (inert electrode working time of 10 s, current density of 1 mA/cm2, and 15 min total electrocoagulation time), which was 6% higher than that of the control (no inert electrode). The energy demand varied from 0.05 kWh/m3 for 85% removal in 5 min, to 0.14 kwh/m3 for 98% removal in 15 min. These results indicate that the REAEC can reduce the energy demands and treatment times compared to conventional electrocoagulation processes for phosphate removal from wastewater.

  8. Spectral features in the cosmic ray fluxes

    Science.gov (United States)

    Lipari, Paolo

    2018-01-01

    The cosmic ray energy distributions contain spectral features, that is narrow energy regions where the slope of the spectrum changes rapidly. The identification and study of these features is of great importance to understand the astrophysical mechanisms of acceleration and propagation that form the spectra. In first approximation a spectral feature is often described as a discontinuous change in slope, however very valuable information is also contained in its width, that is the length of the energy interval where the change in spectral index develops. In this work we discuss the best way to define and parameterize the width a spectral feature, and for illustration discuss some of the most prominent known structures.

  9. Evaluation of the suitability of a plant virus, pepper mild mottle virus, as a surrogate of human enteric viruses for assessment of the efficacy of coagulation-rapid sand filtration to remove those viruses.

    Science.gov (United States)

    Shirasaki, N; Matsushita, T; Matsui, Y; Yamashita, R

    2018-02-01

    Here, we evaluated the removal of three representative human enteric viruses - adenovirus (AdV) type 40, coxsackievirus (CV) B5, and hepatitis A virus (HAV) IB - and one surrogate of human caliciviruses - murine norovirus (MNV) type 1 - by coagulation-rapid sand filtration, using water samples from eight water sources for drinking water treatment plants in Japan. The removal ratios of a plant virus (pepper mild mottle virus; PMMoV) and two bacteriophages (MS2 and φX174) were compared with the removal ratios of human enteric viruses to assess the suitability of PMMoV, MS2, and φX174 as surrogates for human enteric viruses. The removal ratios of AdV, CV, HAV, and MNV, evaluated via the real-time polymerase chain reaction (PCR) method, were 0.8-2.5-log 10 when commercially available polyaluminum chloride (PACl, basicity 1.5) and virgin silica sand were used as the coagulant and filter medium, respectively. The type of coagulant affected the virus removal efficiency, but the age of silica sand used in the rapid sand filtration did not. Coagulation-rapid sand filtration with non-sulfated, high-basicity PACls (basicity 2.1 or 2.5) removed viruses more efficiently than the other aluminum-based coagulants. The removal ratios of MS2 were sometimes higher than those of the three human enteric viruses and MNV, whereas the removal ratios of φX174 tended to be smaller than those of the three human enteric viruses and MNV. In contrast, the removal ratios of PMMoV were similar to and strongly correlated with those of the three human enteric viruses and MNV. Thus, PMMoV appears to be a suitable surrogate for human enteric viruses for the assessment of the efficacy of coagulation-rapid sand filtration to remove viruses. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Rapid screening of guar gum using portable Raman spectral identification methods.

    Science.gov (United States)

    Srivastava, Hirsch K; Wolfgang, Steven; Rodriguez, Jason D

    2016-01-25

    Guar gum is a well-known inactive ingredient (excipient) used in a variety of oral pharmaceutical dosage forms as a thickener and stabilizer of suspensions and as a binder of powders. It is also widely used as a food ingredient in which case alternatives with similar properties, including chemically similar gums, are readily available. Recent supply shortages and price fluctuations have caused guar gum to come under increasing scrutiny for possible adulteration by substitution of cheaper alternatives. One way that the U.S. FDA is attempting to screen pharmaceutical ingredients at risk for adulteration or substitution is through field-deployable spectroscopic screening. Here we report a comprehensive approach to evaluate two field-deployable Raman methods--spectral correlation and principal component analysis--to differentiate guar gum from other gums. We report a comparison of the sensitivity of the spectroscopic screening methods with current compendial identification tests. The ability of the spectroscopic methods to perform unambiguous identification of guar gum compared to other gums makes them an enhanced surveillance alternative to the current compendial identification tests, which are largely subjective in nature. Our findings indicate that Raman spectral identification methods perform better than compendial identification methods and are able to distinguish guar gum from other gums with 100% accuracy for samples tested by spectral correlation and principal component analysis. Published by Elsevier B.V.

  11. Spectral Sharpening of Color Sensors: Diagonal Color Constancy and Beyond

    OpenAIRE

    Vazquez-Corral, Javier; Bertalmío, Marcelo

    2014-01-01

    It has now been 20 years since the seminal work by Finlayson et al. on the use/nof spectral sharpening of sensors to achieve diagonal color constancy. Spectral sharpening is/nstill used today by numerous researchers for different goals unrelated to the original goal/nof diagonal color constancy e.g., multispectral processing, shadow removal, location of/nunique hues. This paper reviews the idea of spectral sharpening through the lens of what/nis known today in color constancy, describes the d...

  12. Spectral imaging toolbox: segmentation, hyperstack reconstruction, and batch processing of spectral images for the determination of cell and model membrane lipid order.

    Science.gov (United States)

    Aron, Miles; Browning, Richard; Carugo, Dario; Sezgin, Erdinc; Bernardino de la Serna, Jorge; Eggeling, Christian; Stride, Eleanor

    2017-05-12

    Spectral imaging with polarity-sensitive fluorescent probes enables the quantification of cell and model membrane physical properties, including local hydration, fluidity, and lateral lipid packing, usually characterized by the generalized polarization (GP) parameter. With the development of commercial microscopes equipped with spectral detectors, spectral imaging has become a convenient and powerful technique for measuring GP and other membrane properties. The existing tools for spectral image processing, however, are insufficient for processing the large data sets afforded by this technological advancement, and are unsuitable for processing images acquired with rapidly internalized fluorescent probes. Here we present a MATLAB spectral imaging toolbox with the aim of overcoming these limitations. In addition to common operations, such as the calculation of distributions of GP values, generation of pseudo-colored GP maps, and spectral analysis, a key highlight of this tool is reliable membrane segmentation for probes that are rapidly internalized. Furthermore, handling for hyperstacks, 3D reconstruction and batch processing facilitates analysis of data sets generated by time series, z-stack, and area scan microscope operations. Finally, the object size distribution is determined, which can provide insight into the mechanisms underlying changes in membrane properties and is desirable for e.g. studies involving model membranes and surfactant coated particles. Analysis is demonstrated for cell membranes, cell-derived vesicles, model membranes, and microbubbles with environmentally-sensitive probes Laurdan, carboxyl-modified Laurdan (C-Laurdan), Di-4-ANEPPDHQ, and Di-4-AN(F)EPPTEA (FE), for quantification of the local lateral density of lipids or lipid packing. The Spectral Imaging Toolbox is a powerful tool for the segmentation and processing of large spectral imaging datasets with a reliable method for membrane segmentation and no ability in programming required. The

  13. An experiment with spectral analysis of emotional speech affected by orthodontic appliances

    Science.gov (United States)

    Přibil, Jiří; Přibilová, Anna; Ďuračková, Daniela

    2012-11-01

    The contribution describes the effect of the fixed and removable orthodontic appliances on spectral properties of emotional speech. Spectral changes were analyzed and evaluated by spectrograms and mean Welch’s periodograms. This alternative approach to the standard listening test enables to obtain objective comparison based on statistical analysis by ANOVA and hypothesis tests. Obtained results of analysis performed on short sentences of a female speaker in four emotional states (joyous, sad, angry, and neutral) show that, first of all, the removable orthodontic appliance affects the spectrograms of produced speech.

  14. Towards a method of rapid extraction of strontium-90 from urine: urine pretreatment and alkali metal removal

    Energy Technology Data Exchange (ETDEWEB)

    Hawkins, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Dietz, M. [Argonne National Lab. (ANL), Argonne, IL (United States); Kaminski, M. [Argonne National Lab. (ANL), Argonne, IL (United States); Mertz, C. [Argonne National Lab. (ANL), Argonne, IL (United States); Shkrob, I. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-03-01

    A technical program to support the Centers of Disease Control and Prevention is being developed to provide an analytical method for rapid extraction of Sr-90 from urine, with the intent of assessing the general population’s exposure during an emergency response to a radiological terrorist event. Results are presented on the progress in urine sample preparation and chemical separation steps that provide an accurate and quantitative detection of Sr-90 based upon an automated column separation sequence and a liquid scintillation assay. Batch extractions were used to evaluate the urine pretreatment and the column separation efficiency and loading capacity based upon commercial, extractant-loaded resins. An efficient pretreatment process for decolorizing and removing organics from urine without measurable loss of radiostrontium from the sample was demonstrated. In addition, the Diphonix® resin shows promise for the removal of high concentrations of common strontium interferents in urine as a first separation step for Sr-90 analysis.

  15. Exploiting physical constraints for multi-spectral exo-planet detection

    Science.gov (United States)

    Thiébaut, Éric; Devaney, Nicholas; Langlois, Maud; Hanley, Kenneth

    2016-07-01

    We derive a physical model of the on-axis PSF for a high contrast imaging system such as GPI or SPHERE. This model is based on a multi-spectral Taylor series expansion of the diffraction pattern and predicts that the speckles should be a combination of spatial modes with deterministic chromatic magnification and weighting. We propose to remove most of the residuals by fitting this model on a set of images at multiple wavelengths and times. On simulated data, we demonstrate that our approach achieves very good speckle suppression without additional heuristic parameters. The residual speckles1, 2 set the most serious limitation in the detection of exo-planets in high contrast coronographic images provided by instruments such as SPHERE3 at the VLT, GPI4, 5 at Gemini, or SCExAO6 at Subaru. A number of post-processing methods have been proposed to remove as much as possible of the residual speckles while preserving the signal from the planets. These methods exploit the fact that the speckles and the planetary signal have different temporal and spectral behaviors. Some methods like LOCI7 are based on angular differential imaging8 (ADI), spectral differential imaging9, 10 (SDI), or on a combination of ADI and SDI.11 Instead of working on image differences, we propose to tackle the exo-planet detection as an inverse problem where a model of the residual speckles is fit on the set of multi-spectral images and, possibly, multiple exposures. In order to reduce the number of degrees of freedom, we impose specific constraints on the spatio-spectral distribution of stellar speckles. These constraints are deduced from a multi-spectral Taylor series expansion of the diffraction pattern for an on-axis source which implies that the speckles are a combination of spatial modes with deterministic chromatic magnification and weighting. Using simulated data, the efficiency of speckle removal by fitting the proposed multi-spectral model is compared to the result of using an approximation

  16. Rapid, Selective Heavy Metal Removal from Water by a Metal-Organic Framework/Polydopamine Composite.

    Science.gov (United States)

    Sun, Daniel T; Peng, Li; Reeder, Washington S; Moosavi, Seyed Mohamad; Tiana, Davide; Britt, David K; Oveisi, Emad; Queen, Wendy L

    2018-03-28

    Drinking water contamination with heavy metals, particularly lead, is a persistent problem worldwide with grave public health consequences. Existing purification methods often cannot address this problem quickly and economically. Here we report a cheap, water stable metal-organic framework/polymer composite, Fe-BTC/PDA, that exhibits rapid, selective removal of large quantities of heavy metals, such as Pb 2+ and Hg 2+ , from real world water samples. In this work, Fe-BTC is treated with dopamine, which undergoes a spontaneous polymerization to polydopamine (PDA) within its pores via the Fe 3+ open metal sites. The PDA, pinned on the internal MOF surface, gains extrinsic porosity, resulting in a composite that binds up to 1634 mg of Hg 2+ and 394 mg of Pb 2+ per gram of composite and removes more than 99.8% of these ions from a 1 ppm solution, yielding drinkable levels in seconds. Further, the composite properties are well-maintained in river and seawater samples spiked with only trace amounts of lead, illustrating unprecedented selectivity. Remarkably, no significant uptake of competing metal ions is observed even when interferents, such as Na + , are present at concentrations up to 14 000 times that of Pb 2+ . The material is further shown to be resistant to fouling when tested in high concentrations of common organic interferents, like humic acid, and is fully regenerable over many cycles.

  17. A field technique for rapid lithological discrimination and ore mineral ...

    Indian Academy of Sciences (India)

    This work illustrates the efficiency of field spectroscopy for rapid identification of minerals in ore body, alteration zone and host rocks. The adopted procedure involves collection of field spectra, their processing for noise, spectral matching and spectral un-mixing with selected library end-members. Average weighted spectral ...

  18. Detection of undistorted continuous wave (CW) electron paramagnetic resonance (EPR) spectra with non-adiabatic rapid sweep (NARS) of the magnetic field

    Science.gov (United States)

    Kittell, Aaron W.; Camenisch, Theodore G.; Ratke, Joseph J.; Sidabras, Jason W.; Hyde, James S.

    2011-01-01

    A continuous wave (CW) electron paramagnetic resonance (EPR) spectrum is typically displayed as the first harmonic response to the application of 100 kHz magnetic field modulation, which is used to enhance sensitivity by reducing the level of 1/f noise. However, magnetic field modulation of any amplitude causes spectral broadening and sacrifices EPR spectral intensity by at least a factor of two. In the work presented here, a CW rapid-scan spectroscopic technique that avoids these compromises and also provides a means of avoiding 1/f noise is developed. This technique, termed non-adiabatic rapid sweep (NARS) EPR, consists of repetitively sweeping the polarizing magnetic field in a linear manner over a spectral fragment with a small coil at a repetition rate that is sufficiently high that receiver noise, microwave phase noise, and environmental microphonics, each of which has 1/f characteristics, are overcome. Nevertheless, the rate of sweep is sufficiently slow that adiabatic responses are avoided and the spin system is always close to thermal equilibrium. The repetitively acquired spectra from the spectral fragment are averaged. Under these conditions, undistorted pure absorption spectra are obtained without broadening or loss of signal intensity. A digital filter such as a moving average is applied to remove high frequency noise, which is approximately equivalent in bandwidth to use of an integrating time constant in conventional field modulation with lock-in detection. Nitroxide spectra at L- and X-band are presented. PMID:21741868

  19. Evaluating the capabilities of vegetation spectral indices on chlorophyll content estimation at Sentinel-2 spectral resolutions

    Science.gov (United States)

    Sun, Qi; Jiao, Quanjun; Dai, Huayang

    2018-03-01

    Chlorophyll is an important pigment in green plants for photosynthesis and obtaining the energy for growth and development. The rapid, nondestructive and accurate estimation of chlorophyll content is significant for understanding the crops growth, monitoring the disease and insect, and assessing the yield of crops. Sentinel-2 equipped with the Multi-Spectral Instrument (MSI), which will provide images with high spatial, spectral and temporal resolution. It covers the VNIR/SWIR spectral region in 13 bands and incorporates two new spectral bands in the red-edge region and a spatial resolution of 20nm, which can be used to derive vegetation indices using red-edge bands. In this paper, we will focus on assessing the potential of vegetation spectral indices for retrieving chlorophyll content from Sentinel-2 at different angles. Subsequently, we used in-situ spectral data and Sentinel-2 data to test the relationship between VIs and chlorophyll content. The REP, MTCI, CIred-edge, CIgreen, Macc01, TCARI/OSAVI [705,750], NDRE1 and NDRE2 were calculated. NDRE2 index displays a strongly similar result for hyperspectral and simulated Sentinel-2 spectral bands (R2 =0.53, R2 =0.51, for hyperspectral and Sentinel-2, respectively). At different observation angles, NDRE2 has the smallest difference in performance (R2 = 0.51, R2 =0.64, at 0° and 15° , respectively).

  20. SPECTRAL EVOLUTION OF THE 2010 SEPTEMBER GAMMA-RAY FLARE FROM THE CRAB NEBULA

    International Nuclear Information System (INIS)

    Vittorini, V.; Tavani, M.; Donnarumma, I.; Trois, A.; Del Monte, E.; Evangelista, Y.; Lazzarotto, F.; Pacciani, L.; Pucella, G.; Striani, E.; Caraveo, P.; Giuliani, A.; Mereghetti, S.; Pellizzoni, A.; Ferrari, A.; Barbiellini, G.; Bulgarelli, A.; Cattaneo, P. W.; Colafrancesco, S.; Pilia, M.

    2011-01-01

    Strong gamma-ray flares from the Crab Nebula have been recently discovered by AGILE and confirmed by Fermi-LAT. We study here the spectral evolution in the gamma-ray energy range above 50 MeV of the 2010 September flare that was simultaneously detected by AGILE and Fermi-LAT. We revisit the AGILE spectral data and present an emission model based on rapid (within 1 day) acceleration followed by synchrotron cooling. We show that this model successfully explains both the published AGILE and Fermi-LAT spectral data showing a rapid rise and a decay within 2 and 3 days. Our analysis constrains the acceleration timescale and mechanism, the properties of the particle distribution function, and the local magnetic field. The combination of very rapid acceleration, emission well above 100 MeV, and the spectral evolution consistent with synchrotron cooling contradicts the idealized scenario predicting an exponential cutoff at photon energies above 100 MeV. We also consider a variation of our model based on even shorter acceleration and decay timescales, which can be consistent with the published averaged properties.

  1. Object-based assessment of burn severity in diseased forests using high-spatial and high-spectral resolution MASTER airborne imagery

    Science.gov (United States)

    Chen, Gang; Metz, Margaret R.; Rizzo, David M.; Dillon, Whalen W.; Meentemeyer, Ross K.

    2015-04-01

    Forest ecosystems are subject to a variety of disturbances with increasing intensities and frequencies, which may permanently change the trajectories of forest recovery and disrupt the ecosystem services provided by trees. Fire and invasive species, especially exotic disease-causing pathogens and insects, are examples of disturbances that together could pose major threats to forest health. This study examines the impacts of fire and exotic disease (sudden oak death) on forests, with an emphasis on the assessment of post-fire burn severity in a forest where trees have experienced three stages of disease progression pre-fire: early-stage (trees retaining dried foliage and fine twigs), middle-stage (trees losing fine crown fuels), and late-stage (trees falling down). The research was conducted by applying Geographic Object-Based Image Analysis (GEOBIA) to MASTER airborne images that were acquired immediately following the fire for rapid assessment and contained both high-spatial (4 m) and high-spectral (50 bands) resolutions. Although GEOBIA has gradually become a standard tool for analyzing high-spatial resolution imagery, high-spectral resolution data (dozens to hundreds of bands) can dramatically reduce computation efficiency in the process of segmentation and object-based variable extraction, leading to complicated variable selection for succeeding modeling. Hence, we also assessed two widely used band reduction algorithms, PCA (principal component analysis) and MNF (minimum noise fraction), for the delineation of image objects and the subsequent performance of burn severity models using either PCA or MNF derived variables. To increase computation efficiency, only the top 5 PCA and MNF and top 10 PCA and MNF components were evaluated, which accounted for 10% and 20% of the total number of the original 50 spectral bands, respectively. Results show that if no band reduction was applied the models developed for the three stages of disease progression had relatively

  2. Evaluation of pharmaceuticals removal by sewage sludge-derived adsorbents with rapid small-scale column tests

    Science.gov (United States)

    Zhang, P.; Ding, R.; Wallace, R.; Bandosz, T.

    2015-12-01

    New composite adsorbents were developed by pyrolyzing sewage sludge and fish waste (75:25 or 90:10 dry mass ratio) at 650 oC and 950 oC. Batch adsorption experiments demonstrated that the composite adsorbents were able to adsorb a wide range of organic contaminants (volatile organic compounds, pharmaceuticals and endocrine disrupting compounds (EDCs), and nitrosamine disinfection byproducts) with high capacities. Here we further examine the performance of the adsorbents for the simultaneous removal of 8 pharmaceuticals and EDCs with rapid small-scale column tests (RSSCT). Results show that the order of breakthrough in RSSCT is in general consistent with the affinity determined via batch tests. As expected, the maximum amount of adsorption for each compound obtained from RSSCT is identical to or less than that obtained from batch tests (with only one exception), due to adsorption kinetics. However, despite the very different input concentration (1 mg/L vs. 100 mg/L) and contact time (2 min empty bed contact time vs. 16 hour equilibrium time) used in RSSCT and batch tests, the maximum amount of pharmaceuticals and EDCs adsorbed under RSSCT is still about one half of that under equilibrium batch tests, validating the approach of using batch tests with much higher input concentrations to determine adsorption capacities. Results of a pilot-scale column test in a drinking water treatment plant for pharmaceuticals removal will also be presented.

  3. Spectrally efficient polarization multiplexed direct-detection OFDM system without frequency gap.

    Science.gov (United States)

    Wei, Chia-Chien; Zeng, Wei-Siang; Lin, Chun-Ting

    2016-01-25

    We experimentally demonstrate a spectrally efficient direct-detection orthogonal frequency-division multiplexing (DD-OFDM) system. In addition to polarization-division multiplexing, removing the frequency gap further improves the spectral efficiency of the OFDM system. The frequency gap between a reference carrier and OFDM subcarriers avoids subcarrier-to-subcarrier beating interference (SSBI) in traditional DD-OFDM systems. Without dynamic polarization control, the resulting interference after square-law direct detection in the proposed gap-less system is polarization-dependent and composed of linear inter-carrier interference (ICI) and nonlinear SSBI. Thus, this work proposes an iterative multiple-input multiple-output detection scheme to remove the mixed polarization-dependent interference. Compared to the previous scheme, which only removes ICI, the proposed scheme can further eliminate SSBI to achieve the improvement of ∼ 7 dB in signal-to-noise ratio. Without the need for polarization control, we successfully utilize 7-GHz bandwidth to transmit a 39.5-Gbps polarization multiplexed OFDM signal over 100 km.

  4. Spectral and dual-energy X-ray imaging for medical applications

    Science.gov (United States)

    Fredenberg, Erik

    2018-01-01

    Spectral imaging is an umbrella term for energy-resolved X-ray imaging in medicine. The technique makes use of the energy dependence of X-ray attenuation to either increase the contrast-to-noise ratio, or to provide quantitative image data and reduce image artefacts by so-called material decomposition. Spectral imaging is not new, but has gained interest in recent years because of rapidly increasing availability of spectral and dual-energy CT and the dawn of energy-resolved photon-counting detectors. This review examines the current technological status of spectral and dual-energy imaging and a number of practical applications of the technology in medicine.

  5. Sulfur rich microporous polymer enables rapid and efficient removal of mercury(II) from water.

    Science.gov (United States)

    Xu, Dan; Wu, Winston Duo; Qi, Hao-Jun; Yang, Rui-Xia; Deng, Wei-Qiao

    2018-04-01

    Design and synthesis of adsorbents for efficient decontamination of hazardous contaminants Hg 2+ from wastewater, based on a facile and economical strategy, is an attractive target. Here, a novel sulfur rich microporous polymer (sulfur content of 31.4 wt %) with high surface area as well as densely populated sulfur atom with fast accessibility was reported to remove mercury (II) from water. The as prepared polymer (SMP) exhibited high binding affinity, high adsorption capacities, rapid adsorption kinetics, and good recyclability for Hg 2+ . The adsorption capacity of SMP was 595.2 mg g -1 . Furthermore, SMP could reduce trace concentrations of Hg 2+ from 200 p. p. b. to a level below drinking water standards (2 p. p. b.) within 3 min. This work allows large-scale production of sulfur rich porous materials for the practical application in water treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. An investigation into the rapid removal of tetracycline using multilayered graphene-phase biochar derived from waste chicken feather.

    Science.gov (United States)

    Li, Huiqin; Hu, Jingtao; Meng, Yue; Su, Jinhua; Wang, Xiaojing

    2017-12-15

    This study investigated the removal of tetracycline (TC) using multilayered graphene-phase biochar (MGB) derived from waste chicken feather. MGB was produced through a two-stage carbonization and KOH-activation method. MGB was characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared (FT-IR), Raman spectra, Zeta potential and elemental analysis. Various chemical functional groups were demonstrated on the surface of MGB. MGB was featured by a very large BET surface area of 1838m 2 /g. A rapid equilibrium (within 30s) and an ultrahigh removal efficiency (up to 99.65%) were obtained when MGB was used in the adsorption of TCs. The adsorption processes were temperature-dependent and the maximum adsorption capacity of MGB was 388.33mg/g at 30°C. The data of adsorption isotherms and kinetics were represented well by the Langmuir and Elovich models, respectively. The chemical monolayer adsorption could play an important role in this process. Furthermore, the adsorption of MGB was tolerant with wide pH, high ionic strength and even co-existing anions. Regeneration experiments indicated the removal efficiency was still satisfied (96.61%) even after four cycles. These results have important implications for the future application of animal waste-derived adsorbents in the treatment of wastewater containing antibiotic residues. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Rapid small-scale column testing of granular activated carbon for organic micro-pollutant removal in treated domestic wastewater.

    Science.gov (United States)

    Zietzschmann, F; Müller, J; Sperlich, A; Ruhl, A S; Meinel, F; Altmann, J; Jekel, M

    2014-01-01

    This study investigates the applicability of the rapid small-scale column test (RSSCT) concept for testing of granular activated carbon (GAC) for organic micro-pollutants (OMPs) removal from wastewater treatment plant (WWTP) effluent. The chosen experimental setup was checked using pure water, WWTP effluent, different GAC products, and variable hydrodynamic conditions with different flow velocities and differently sized GAC, as well as different empty bed contact times (EBCTs). The setup results in satisfying reproducibility and robustness. RSSCTs in combination with WWTP effluent are effective when comparing the OMP removal potentials of different GAC products and are a useful tool for the estimation of larger filters. Due to the potentially high competition between OMPs and bulk organics, breakthrough curves are likely to have unfavorable shapes when treating WWTP effluent. This effect can be counteracted by extending the EBCT. With respect to the strong competition observed in GAC treatment of WWTP effluent, the small organic acid and neutral substances are retained longer in the RSSCT filters and are likely to cause the majority of the observed adsorption competition with OMPs.

  8. Airborne Multi-Spectral Minefield Survey

    Science.gov (United States)

    2005-05-01

    Swedish Defence Research Agency), GEOSPACE (Austria), GTD ( Ingenieria de Sistemas y Software Industrial, Spain), IMEC (Ineruniversity MicroElectronic...RTO-MP-SET-092 18 - 1 UNCLASSIFIED/UNLIMITED UNCLASSIFIED/UNLIMITED Airborne Multi-Spectral Minefield Survey Dirk-Jan de Lange, Eric den...actions is the severe lack of baseline information. To respond to this in a rapid way, cost-efficient data acquisition methods are a key issue. de

  9. Multi-Scale Residual Convolutional Neural Network for Haze Removal of Remote Sensing Images

    Directory of Open Access Journals (Sweden)

    Hou Jiang

    2018-06-01

    Full Text Available Haze removal is a pre-processing step that operates on at-sensor radiance data prior to the physically based image correction step to enhance hazy imagery visually. Most current haze removal methods focus on point-to-point operations and utilize information in the spectral domain, without taking consideration of the multi-scale spatial information of haze. In this paper, we propose a multi-scale residual convolutional neural network (MRCNN for haze removal of remote sensing images. MRCNN utilizes 3D convolutional kernels to extract spatial–spectral correlation information and abstract features from surrounding neighborhoods for haze transmission estimation. It takes advantage of dilated convolution to aggregate multi-scale contextual information for the purpose of improving its prediction accuracy. Meanwhile, residual learning is utilized to avoid the loss of weak information while deepening the network. Our experiments indicate that MRCNN performs accurately, achieving an extremely low validation error and testing error. The haze removal results of several scenes of Landsat 8 Operational Land Imager (OLI data show that the visibility of the dehazed images is significantly improved, and the color of recovered surface is consistent with the actual scene. Quantitative analysis proves that the dehazed results of MRCNN are superior to the traditional methods and other networks. Additionally, a comparison to haze-free data illustrates the spectral consistency after haze removal and reveals the changes in the vegetation index.

  10. [Progress in the spectral library based protein identification strategy].

    Science.gov (United States)

    Yu, Derui; Ma, Jie; Xie, Zengyan; Bai, Mingze; Zhu, Yunping; Shu, Kunxian

    2018-04-25

    Exponential growth of the mass spectrometry (MS) data is exhibited when the mass spectrometry-based proteomics has been developing rapidly. It is a great challenge to develop some quick, accurate and repeatable methods to identify peptides and proteins. Nowadays, the spectral library searching has become a mature strategy for tandem mass spectra based proteins identification in proteomics, which searches the experiment spectra against a collection of confidently identified MS/MS spectra that have been observed previously, and fully utilizes the abundance in the spectrum, peaks from non-canonical fragment ions, and other features. This review provides an overview of the implement of spectral library search strategy, and two key steps, spectral library construction and spectral library searching comprehensively, and discusses the progress and challenge of the library search strategy.

  11. Using GIS servers and interactive maps in spectral data sharing and administration: Case study of Ahvaz Spectral Geodatabase Platform (ASGP)

    Science.gov (United States)

    Karami, Mojtaba; Rangzan, Kazem; Saberi, Azim

    2013-10-01

    With emergence of air-borne and space-borne hyperspectral sensors, spectroscopic measurements are gaining more importance in remote sensing. Therefore, the number of available spectral reference data is constantly increasing. This rapid increase often exhibits a poor data management, which leads to ultimate isolation of data on disk storages. Spectral data without precise description of the target, methods, environment, and sampling geometry cannot be used by other researchers. Moreover, existing spectral data (in case it accompanied with good documentation) become virtually invisible or unreachable for researchers. Providing documentation and a data-sharing framework for spectral data, in which researchers are able to search for or share spectral data and documentation, would definitely improve the data lifetime. Relational Database Management Systems (RDBMS) are main candidates for spectral data management and their efficiency is proven by many studies and applications to date. In this study, a new approach to spectral data administration is presented based on spatial identity of spectral samples. This method benefits from scalability and performance of RDBMS for storage of spectral data, but uses GIS servers to provide users with interactive maps as an interface to the system. The spectral files, photographs and descriptive data are considered as belongings of a geospatial object. A spectral processing unit is responsible for evaluation of metadata quality and performing routine spectral processing tasks for newly-added data. As a result, by using internet browser software the users would be able to visually examine availability of data and/or search for data based on descriptive attributes associated to it. The proposed system is scalable and besides giving the users good sense of what data are available in the database, it facilitates participation of spectral reference data in producing geoinformation.

  12. A spectral differential characterization of low-mass companions

    Directory of Open Access Journals (Sweden)

    Lyubchik Y.

    2013-04-01

    Full Text Available We present a new approach with which the dynamical mass of low-mass companions around cool stars can be found. In order to discover companions to late-type stars the stellar spectrum is removed. For this we substract two spectra obtained at different orbital phases from each other in order to discover the companion spectrum in the difference spectrum in which the companion lines appear twice (positive and negative signal. The resulting radial velocity difference of these two signals provides the true mass of the companion. For our test case GJ1046, an M2V dwarf with a low-mass companion that most likely is a brown dwarf we select the CO line region in the K-band. We show that the dynamical mass of a faint companion to an M dwarf can be determined using our spectral differential technique. Only if the companion rotates rapidly and has a small radial velocity amplitude due to a high mass, does blending occur for all lines so that our approach fails. In addition to determining the companion mass, we restore the single companion spectrum from the difference spectrum using singular value decomposition.

  13. Monitoring of Water Spectral Pattern Reveals Differences in Probiotics Growth When Used for Rapid Bacteria Selection.

    Directory of Open Access Journals (Sweden)

    Aleksandar Slavchev

    Full Text Available Development of efficient screening method coupled with cell functionality evaluation is highly needed in contemporary microbiology. The presented novel concept and fast non-destructive method brings in to play the water spectral pattern of the solution as a molecular fingerprint of the cell culture system. To elucidate the concept, NIR spectroscopy with Aquaphotomics were applied to monitor the growth of sixteen Lactobacillus bulgaricus one Lactobacillus pentosus and one Lactobacillus gasseri bacteria strains. Their growth rate, maximal optical density, low pH and bile tolerances were measured and further used as a reference data for analysis of the simultaneously acquired spectral data. The acquired spectral data in the region of 1100-1850nm was subjected to various multivariate data analyses - PCA, OPLS-DA, PLSR. The results showed high accuracy of bacteria strains classification according to their probiotic strength. Most informative spectral fingerprints covered the first overtone of water, emphasizing the relation of water molecular system to cell functionality.

  14. Efficient 3D frequency response modeling with spectral accuracy by the rapid expansion method

    KAUST Repository

    Chu, Chunlei

    2012-07-01

    Frequency responses of seismic wave propagation can be obtained either by directly solving the frequency domain wave equations or by transforming the time domain wavefields using the Fourier transform. The former approach requires solving systems of linear equations, which becomes progressively difficult to tackle for larger scale models and for higher frequency components. On the contrary, the latter approach can be efficiently implemented using explicit time integration methods in conjunction with running summations as the computation progresses. Commonly used explicit time integration methods correspond to the truncated Taylor series approximations that can cause significant errors for large time steps. The rapid expansion method (REM) uses the Chebyshev expansion and offers an optimal solution to the second-order-in-time wave equations. When applying the Fourier transform to the time domain wavefield solution computed by the REM, we can derive a frequency response modeling formula that has the same form as the original time domain REM equation but with different summation coefficients. In particular, the summation coefficients for the frequency response modeling formula corresponds to the Fourier transform of those for the time domain modeling equation. As a result, we can directly compute frequency responses from the Chebyshev expansion polynomials rather than the time domain wavefield snapshots as do other time domain frequency response modeling methods. When combined with the pseudospectral method in space, this new frequency response modeling method can produce spectrally accurate results with high efficiency. © 2012 Society of Exploration Geophysicists.

  15. Rice hull/MnFe2O4 composite: Preparation, characterization and its rapid microwave-assisted COD removal for organic wastewater

    International Nuclear Information System (INIS)

    Lv Shuangshuang; Chen Xuegang; Ye Ying; Yin Suhang; Cheng Jipeng; Xia Meisheng

    2009-01-01

    Adsorbent/ferrite composites can adsorb and degrade organics in the organic wastewater treatment. In this study, a rice hull/MnFe 2 O 4 composite (RHM) was prepared via calcination under nitrogen atmosphere and was used to treat organic wastewater with the assistance of microwave radiation. Rice hull was pyrolysed to a porous substrate that consisted of silica and activated carbon under high temperature. Monodisperse spinel MnFe 2 O 4 nanoparticles whose mean diameter is around 59 nm are distributed on the substrate. With the assistance of microwave radiation, RHM was motivated to a hotspot of adsorption and catalysis which could remove more than 70% COD of wastewater within 6 min. The maximum COD removal was 73.5% when the concentration of RHM was 15 mg mL -1 and the irradiation time of microwave radiation was 6 min. Although the BET surface area and iodine value of RHM are half of rice hull ash (RHA), the COD removal of RHM is 7-20% higher than that of RHA. It is attributed to the presence of MnFe 2 O 4 , which enhances the catalytic activity of RHM. RHM can be regenerated via water washing. However, the surface area and the maximum COD removal of RHM decrease for each regeneration cycle. With the advantages of low cost and rapid processing, this novel rice hull/MnFe 2 O 4 composite could gain promising application in wastewater treating-agent.

  16. Spectral shape of one-photon luminescence from single gold nanorods

    Directory of Open Access Journals (Sweden)

    Te Wen

    2017-12-01

    Full Text Available Light emission from gold nanoparticles was investigated with ultra-narrow-band notch filters to obtain the complete spectral shape. The anti-Stokes emission band was observed at all excitation wavelengths. The spectral shape of the anti-Stokes emission could be well fitted by a Fermi–Dirac-like line shape, while the spectral profile of the Stokes emission could be fitted by a Lorentzian line shape. The electron distribution and local surface plasmon resonance jointly determined the spectral shape. Additionally, we found that the anti-Stokes emission intensity increased more rapidly compared with that of the Stokes emission as illumination power was increased. This phenomenon can be understood from the temperature dependence of the electron distribution owing to photothermal effects.

  17. [An improved low spectral distortion PCA fusion method].

    Science.gov (United States)

    Peng, Shi; Zhang, Ai-Wu; Li, Han-Lun; Hu, Shao-Xing; Meng, Xian-Gang; Sun, Wei-Dong

    2013-10-01

    Aiming at the spectral distortion produced in PCA fusion process, the present paper proposes an improved low spectral distortion PCA fusion method. This method uses NCUT (normalized cut) image segmentation algorithm to make a complex hyperspectral remote sensing image into multiple sub-images for increasing the separability of samples, which can weaken the spectral distortions of traditional PCA fusion; Pixels similarity weighting matrix and masks were produced by using graph theory and clustering theory. These masks are used to cut the hyperspectral image and high-resolution image into some sub-region objects. All corresponding sub-region objects between the hyperspectral image and high-resolution image are fused by using PCA method, and all sub-regional integration results are spliced together to produce a new image. In the experiment, Hyperion hyperspectral data and Rapid Eye data were used. And the experiment result shows that the proposed method has the same ability to enhance spatial resolution and greater ability to improve spectral fidelity performance.

  18. LTR retrotransposon landscape in Medicago truncatula: more rapid removal than in rice

    Directory of Open Access Journals (Sweden)

    Liu Jin-Song

    2008-08-01

    Full Text Available Abstract Background Long terminal repeat retrotransposons (LTR elements are ubiquitous Eukaryotic TEs that transpose through RNA intermediates. Accounting for significant proportion of many plant genomes, LTR elements have been well established as one of the major forces underlying the evolution of plant genome size, structure and function. The accessibility of more than 40% of genomic sequences of the model legume Medicago truncatula (Mt has made the comprehensive study of its LTR elements possible. Results We use a newly developed tool LTR_FINDER to identify LTR retrotransposons in the Mt genome and detect 526 full-length elements as well as a great number of copies related to them. These elements constitute about 9.6% of currently available genomic sequences. They are classified into 85 families of which 64 are reported for the first time. The majority of the LTR retrotransposons belong to either Copia or Gypsy superfamily and the others are categorized as TRIMs or LARDs by their length. We find that the copy-number of Copia-like families is 3 times more than that of Gypsy-like ones but the latter contribute more to the genome. The analysis of PBS and protein-coding domain structure of the LTR families reveals that they tend to use only 4–5 types of tRNAs and many families have quite conservative ORFs besides known TE domains. For several important families, we describe in detail their abundance, conservation, insertion time and structure. We investigate the amplification-deletion pattern of the elements and find that the detectable full-length elements are relatively young and most of them were inserted within the last 0.52 MY. We also estimate that more than ten million bp of the Mt genomic sequences have been removed by the deletion of LTR elements and the removal of the full-length structures in Mt has been more rapid than in rice. Conclusion This report is the first comprehensive description and analysis of LTR retrotransposons in the

  19. Effect of substrate choice and tissue type on tissue preparation for spectral histopathology by Raman microspectroscopy.

    Science.gov (United States)

    Fullwood, Leanne M; Griffiths, Dave; Ashton, Katherine; Dawson, Timothy; Lea, Robert W; Davis, Charles; Bonnier, Franck; Byrne, Hugh J; Baker, Matthew J

    2014-01-21

    Raman spectroscopy is a non-destructive, non-invasive, rapid and economical technique which has the potential to be an excellent method for the diagnosis of cancer and understanding disease progression through retrospective studies of archived tissue samples. Historically, biobanks are generally comprised of formalin fixed paraffin preserved tissue and as a result these specimens are often used in spectroscopic research. Tissue in this state has to be dewaxed prior to Raman analysis to reduce paraffin contributions in the spectra. However, although the procedures are derived from histopathological clinical practice, the efficacy of the dewaxing procedures that are currently employed is questionable. Ineffective removal of paraffin results in corruption of the spectra and previous experiments have shown that the efficacy can depend on the dewaxing medium and processing time. The aim of this study was to investigate the influence of commonly used spectroscopic substrates (CaF2, Spectrosil quartz and low-E slides) and the influence of different histological tissue types (normal, cancerous and metastatic) on tissue preparation and to assess their use for spectral histopathology. Results show that CaF2 followed by Spectrosil contribute the least to the spectral background. However, both substrates retain paraffin after dewaxing. Low-E substrates, which exhibit the most intense spectral background, do not retain wax and resulting spectra are not affected by paraffin peaks. We also show a disparity in paraffin retention depending upon the histological identity of the tissue with abnormal tissue retaining more paraffin than normal.

  20. Spectrally encoded confocal microscopy (SECM) for rapid assessment of breast excision specimens (Conference Presentation)

    Science.gov (United States)

    Brachtel, Elena F.; Johnson, Nicole B.; Huck, Amelia E.; Rice-Stitt, Travis L.; Vangel, Mark G.; Smith, Barbara L.; Tearney, Guillermo J.; Kang, DongKyun

    2016-03-01

    Unacceptably large percentage (20-40%) of breast cancer lumpectomy patients are required to undergo multiple surgeries when positive margins are found upon post-operative histologic assessment. If the margin status can be determined during surgery, surgeon can resect additional tissues to achieve tumor-free margin, which will reduce the need for additional surgeries. Spectrally encoded confocal microscopy (SECM) is a high-speed reflectance confocal microscopy technology that has a potential to image the entire surgical margin within a short procedural time. Previously, SECM was shown to rapidly image a large area (10 mm by 10 mm) of human esophageal tissue within a short procedural time (15 seconds). When used in lumpectomy, SECM will be able to image the entire margin surface of ~30 cm2 in around 7.5 minutes. SECM images will then be used to determine margin status intra-operatively. In this paper, we present results from a study of testing accuracy of SECM for diagnosing malignant breast tissues. We have imaged freshly-excised breast specimens (N=46) with SECM. SECM images clearly visualized histomorphologic features associated with normal/benign and malignant breast tissues in a similar manner to histologic images. Diagnostic accuracy was tested by comparing SECM diagnoses made by three junior pathologists with corresponding histologic diagnoses made by a senior pathologist. SECM sensitivity and specificity were high, 0.91 and 0.93, respectively. Intra-observer agreement and inter-observer agreement were also high, 0.87 and 0.84, respectively. Results from this study showed that SECM has a potential to accurately determine margin status during breast cancer lumpectomy.

  1. Removing the bottleneck in whole genome sequencing of Mycobacterium tuberculosis for rapid drug resistance analysis: a call to action

    Directory of Open Access Journals (Sweden)

    Ruth McNerney

    2017-03-01

    Full Text Available Whole genome sequencing (WGS can provide a comprehensive analysis of Mycobacterium tuberculosis mutations that cause resistance to anti-tuberculosis drugs. With the deployment of bench-top sequencers and rapid analytical software, WGS is poised to become a useful tool to guide treatment. However, direct sequencing from clinical specimens to provide a full drug resistance profile remains a serious challenge. This article reviews current practices for extracting M. tuberculosis DNA and possible solutions for sampling sputum. Techniques under consideration include enzymatic digestion, physical disruption, chemical degradation, detergent solubilization, solvent extraction, ligand-coated magnetic beads, silica columns, and oligonucleotide pull-down baits. Selective amplification of genomic bacterial DNA in sputum prior to WGS may provide a solution, and differential lysis to reduce the levels of contaminating human DNA is also being explored. To remove this bottleneck and accelerate access to WGS for patients with suspected drug-resistant tuberculosis, it is suggested that a coordinated and collaborative approach be taken to more rapidly optimize, compare, and validate methodologies for sequencing from patient samples.

  2. Improved Electrocoagulation Reactor for Rapid Removal of Phosphate from Wastewater

    KAUST Repository

    Tian, Yushi; He, Weihua; Zhu, Xiuping; Yang, Wulin; Ren, Nanqi; Logan, Bruce E.

    2016-01-01

    by electrocoagulation. The performance of this process, called a reverse-electric field, air cathode electrocoagulation (REAEC) reactor, was tested using domestic wastewater as a function of charging time and electrocoagulation time. REAEC wastewater treatment removed

  3. SPAM- SPECTRAL ANALYSIS MANAGER (UNIX VERSION)

    Science.gov (United States)

    Solomon, J. E.

    1994-01-01

    The Spectral Analysis Manager (SPAM) was developed to allow easy qualitative analysis of multi-dimensional imaging spectrometer data. Imaging spectrometers provide sufficient spectral sampling to define unique spectral signatures on a per pixel basis. Thus direct material identification becomes possible for geologic studies. SPAM provides a variety of capabilities for carrying out interactive analysis of the massive and complex datasets associated with multispectral remote sensing observations. In addition to normal image processing functions, SPAM provides multiple levels of on-line help, a flexible command interpretation, graceful error recovery, and a program structure which can be implemented in a variety of environments. SPAM was designed to be visually oriented and user friendly with the liberal employment of graphics for rapid and efficient exploratory analysis of imaging spectrometry data. SPAM provides functions to enable arithmetic manipulations of the data, such as normalization, linear mixing, band ratio discrimination, and low-pass filtering. SPAM can be used to examine the spectra of an individual pixel or the average spectra over a number of pixels. SPAM also supports image segmentation, fast spectral signature matching, spectral library usage, mixture analysis, and feature extraction. High speed spectral signature matching is performed by using a binary spectral encoding algorithm to separate and identify mineral components present in the scene. The same binary encoding allows automatic spectral clustering. Spectral data may be entered from a digitizing tablet, stored in a user library, compared to the master library containing mineral standards, and then displayed as a timesequence spectral movie. The output plots, histograms, and stretched histograms produced by SPAM can be sent to a lineprinter, stored as separate RGB disk files, or sent to a Quick Color Recorder. SPAM is written in C for interactive execution and is available for two different

  4. Cadmium (II) removal mechanisms in microbial electrolysis cells

    Energy Technology Data Exchange (ETDEWEB)

    Colantonio, Natalie; Kim, Younggy, E-mail: younggy@mcmaster.ca

    2016-07-05

    Highlights: • Rapid removal of Cd(II) was achieved in 24 h using microbial electrolysis cells. • Cathodic reduction (electrodeposition) of Cd(II) cannot explain the rapid removal. • H{sub 2} evolution in microbial electrolysis cells increases local pH near the cathode. • High local pH induces Cd(OH){sub 2} and CdCO{sub 3} precipitation only with electric current. • Neutral pH caused by low current and depleted substrate dissolves the precipitated Cd. - Abstract: Cadmium is a toxic heavy metal, causing serious environmental and human health problems. Conventional methods for removing cadmium from wastewater are expensive and inefficient for low concentrations. Microbial electrolysis cells (MECs) can simultaneously treat wastewater, produce hydrogen gas, and remove heavy metals with low energy requirements. Lab-scale MECs were operated to remove cadmium under various electric conditions: applied voltages of 0.4, 0.6, 0.8, and 1.0 V; and a fixed cathode potential of −1.0 V vs. Ag/AgCl. Regardless of the electric condition, rapid removal of cadmium was demonstrated (50–67% in 24 h); however, cadmium concentration in solution increased after the electric current dropped with depleted organic substrate under applied voltage conditions. For the fixed cathode potential, the electric current was maintained even after substrate depletion and thus cadmium concentration did not increase. These results can be explained by three different removal mechanisms: cathodic reduction; Cd(OH){sub 2} precipitation; and CdCO{sub 3} precipitation. When the current decreased with depleted substrates, local pH at the cathode was no longer high due to slowed hydrogen evolution reaction (2H{sup +} + 2e{sup −} → H{sub 2}); thus, the precipitated Cd(OH){sub 2} and CdCO{sub 3} started dissolving. To prevent their dissolution, sufficient organic substrates should be provided when MECs are used for cadmium removal.

  5. Rapid Screening of Bovine Milk Oligosaccharides in a Whey Permeate Product and Domestic Animal Milks by Accurate Mass Database and Tandem Mass Spectral Library

    Science.gov (United States)

    Lee, Hyeyoung; Cuthbertson, Daniel J.; Otter, Don E.; Barile, Daniela

    2018-01-01

    A bovine milk oligosaccharide (BMO) library, prepared from cow colostrum, with 34 structures was generated and used to rapidly screen oligosaccharides in domestic animal milks and a whey permeate powder. The novel library was entered into a custom Personal Compound Database and Library (PCDL) and included accurate mass, retention time, and tandem mass spectra. Oligosaccharides in minute-sized samples were separated using nanoliquid chromatography (nanoLC) coupled to a high resolution and sensitive quadrupole-Time of Flight (Q-ToF) MS system. Using the PCDL, 18 oligosaccharides were found in a BMO-enriched product obtained from whey permeate processing. The usefulness of the analytical system and BMO library was further validated using milks from domestic sheep and buffaloes. Through BMO PCDL searching, 15 and 13 oligosaccharides in the BMO library were assigned in sheep and buffalo milks, respectively, thus demonstrating significant overlap between oligosaccharides in bovine (cow and buffalo) and ovine (sheep) milks. This method was shown to be an efficient, reliable, and rapid tool to identify oligosaccharide structures using automated spectral matching. PMID:27428379

  6. Spectral gamuts and spectral gamut mapping

    Science.gov (United States)

    Rosen, Mitchell R.; Derhak, Maxim W.

    2006-01-01

    All imaging devices have two gamuts: the stimulus gamut and the response gamut. The response gamut of a print engine is typically described in CIE colorimetry units, a system derived to quantify human color response. More fundamental than colorimetric gamuts are spectral gamuts, based on radiance, reflectance or transmittance units. Spectral gamuts depend on the physics of light or on how materials interact with light and do not involve the human's photoreceptor integration or brain processing. Methods for visualizing a spectral gamut raise challenges as do considerations of how to utilize such a data-set for producing superior color reproductions. Recent work has described a transformation of spectra reduced to 6-dimensions called LabPQR. LabPQR was designed as a hybrid space with three explicit colorimetric axes and three additional spectral reconstruction axes. In this paper spectral gamuts are discussed making use of LabPQR. Also, spectral gamut mapping is considered in light of the colorimetric-spectral duality of the LabPQR space.

  7. High-speed atmospheric correction for spectral image processing

    Science.gov (United States)

    Perkins, Timothy; Adler-Golden, Steven; Cappelaere, Patrice; Mandl, Daniel

    2012-06-01

    Land and ocean data product generation from visible-through-shortwave-infrared multispectral and hyperspectral imagery requires atmospheric correction or compensation, that is, the removal of atmospheric absorption and scattering effects that contaminate the measured spectra. We have recently developed a prototype software system for automated, low-latency, high-accuracy atmospheric correction based on a C++-language version of the Spectral Sciences, Inc. FLAASH™ code. In this system, pre-calculated look-up tables replace on-the-fly MODTRAN® radiative transfer calculations, while the portable C++ code enables parallel processing on multicore/multiprocessor computer systems. The initial software has been installed on the Sensor Web at NASA Goddard Space Flight Center, where it is currently atmospherically correcting new data from the EO-1 Hyperion and ALI sensors. Computation time is around 10 s per data cube per processor. Further development will be conducted to implement the new atmospheric correction software on board the upcoming HyspIRI mission's Intelligent Payload Module, where it would generate data products in nearreal time for Direct Broadcast to the ground. The rapid turn-around of data products made possible by this software would benefit a broad range of applications in areas of emergency response, environmental monitoring and national defense.

  8. Rectangular spectral collocation

    KAUST Repository

    Driscoll, Tobin A.

    2015-02-06

    Boundary conditions in spectral collocation methods are typically imposed by removing some rows of the discretized differential operator and replacing them with others that enforce the required conditions at the boundary. A new approach based upon resampling differentiated polynomials into a lower-degree subspace makes differentiation matrices, and operators built from them, rectangular without any row deletions. Then, boundary and interface conditions can be adjoined to yield a square system. The resulting method is both flexible and robust, and avoids ambiguities that arise when applying the classical row deletion method outside of two-point scalar boundary-value problems. The new method is the basis for ordinary differential equation solutions in Chebfun software, and is demonstrated for a variety of boundary-value, eigenvalue and time-dependent problems.

  9. Analysis of optical proprieties of the water reservoir Rodolfo Costa e Silva – Itaara, RS, Brazil, with field spectral data and orbital multispectral images

    Directory of Open Access Journals (Sweden)

    Waterloo Pereira Filho

    2007-08-01

    Full Text Available An evaluation of the discrimination of water classes using continuum removal technique applied over spectral data obtained in field and multispectral images classification is presented. The study area was the Rodolfo Costa e Silva water reservoir, located in central region of Rio Grande do Sul (RS State, in Southern region of Brazil. The methodology was based on in situ data collection of: total suspended solids, chlorophyll (a, b and c, water transparency, and bidirectional spectral reflectance. These data were collected in 21 point (samples in May 16, 2006. The continuum removal technique was applied on the spectral data over 4 absorption bands: 400-550nm, 610-640nm, 650-680nm e 580-700nm. The continuum removal parameters analyzed for each absorption band were: depth, area and width. The multispectral images used were CBERS-2/CCD and Landsat 5/TM. The images were acquired in a date nearest to field work and with appropriate weather conditions. These images were corrected by removing atmospheric effects and then classified. According to the results obtained from the continuum removal technique, it was verified that band depth, area and width did not present a good potential to separate different water classes. Digital classification results did not show significant correlations with the limnological parameters collected in field and, therefore, could not be used to characterize spectrally different water classes or compartments. The main problem of establishing relationships between spectral reflectance and water quality parameters was due to the low variability of optical components in the water of Rodolfo Costa e Silva Reservoir. In this case the spectral analyses (considering both techniques were not sensitive to the relative small variations observed in field data.

  10. Rapid manganese removal from mine waters using an aerated packed-bed bioreactor.

    Science.gov (United States)

    Johnson, Karen L; Younger, Paul L

    2005-01-01

    In the UK, the Environmental Quality Standard for manganese has recently been lowered to 30 microg/L (annual average), which is less than the UK Drinking Water Inspectorate's Maximum Permitted Concentration Value (50 microg/L). Current passive treatment systems for manganese removal operate as open-air gravel-bed filters, designed to maximize either influent light and/or dissolved oxygen. This requires large areas of land. A novel enhanced bioremediation treatment system for manganese removal has been developed that consists of a passively aerated subsurface gravel bed. The provision of air at depth and the use of catalytic substrates help overcome the slow kinetics usually associated with manganese oxidation. With a residence time of only 8 h and an influent manganese concentration of approximately 20 mg/L, >95% of the manganese was removed. The treatment system also operates successfully at temperatures as low as 4 degrees C and in total darkness. These observations have positive implications for manganese treatment using this technique in both colder climates and where large areas of land are unavailable. Furthermore, as the operation of this passive treatment system continually generates fresh manganese oxyhydroxide, which is a powerful sorbent for most pollutant metals, it potentially has major ancillary benefits as a removal process for other metals, such as zinc.

  11. Rapid identification of soil cadmium pollution risk at regional scale based on visible and near-infrared spectroscopy

    International Nuclear Information System (INIS)

    Chen, Tao; Chang, Qingrui; Clevers, J.G.P.W.; Kooistra, L.

    2015-01-01

    Soil heavy metal pollution due to long-term sewage irrigation is a serious environmental problem in many irrigation areas in northern China. Quickly identifying its pollution status is an important basis for remediation. Visible-near-infrared reflectance spectroscopy (VNIRS) provides a useful tool. In a case study, 76 soil samples were collected and their reflectance spectra were used to estimate cadmium (Cd) concentration by partial least squares regression (PLSR) and back propagation neural network (BPNN). To reduce noise, six pre-treatments were compared, in which orthogonal signal correction (OSC) was first used in soil Cd estimation. Spectral analysis and geostatistics were combined to identify Cd pollution hotspots. Results showed that Cd was accumulated in topsoil at the study area. OSC can effectively remove irrelevant information to improve prediction accuracy. More accurate estimation was achieved by applying a BPNN. Soil Cd pollution hotspots could be identified by interpolating the predicted values obtained from spectral estimates. - Highlights: • Soil reflectance spectroscopy provides a promising tool for detecting soil contaminants. • Orthogonal signal correction efficiently extracted information from noisy spectra. • Back propagation neural network achieved a more accurate estimation for soil Cd. • Soil Cd pollution hotspots could be identified by interpolating the predicted Cd. - Combining spectral analysis and geostatistics can provide a rapid method for identifying the pollution hotspot of soil heavy metal at regional scale.

  12. A two-dimensionally coincident second difference cosmic ray spike removal method for the fully automated processing of Raman spectra.

    Science.gov (United States)

    Schulze, H Georg; Turner, Robin F B

    2014-01-01

    Charge-coupled device detectors are vulnerable to cosmic rays that can contaminate Raman spectra with positive going spikes. Because spikes can adversely affect spectral processing and data analyses, they must be removed. Although both hardware-based and software-based spike removal methods exist, they typically require parameter and threshold specification dependent on well-considered user input. Here, we present a fully automated spike removal algorithm that proceeds without requiring user input. It is minimally dependent on sample attributes, and those that are required (e.g., standard deviation of spectral noise) can be determined with other fully automated procedures. At the core of the method is the identification and location of spikes with coincident second derivatives along both the spectral and spatiotemporal dimensions of two-dimensional datasets. The method can be applied to spectra that are relatively inhomogeneous because it provides fairly effective and selective targeting of spikes resulting in minimal distortion of spectra. Relatively effective spike removal obtained with full automation could provide substantial benefits to users where large numbers of spectra must be processed.

  13. Rapid separation method for {sup 237}Np and Pu isotopes in large soil samples

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, Sherrod L., E-mail: sherrod.maxwell@srs.go [Savannah River Nuclear Solutions, LLC, Building 735-B, Aiken, SC 29808 (United States); Culligan, Brian K.; Noyes, Gary W. [Savannah River Nuclear Solutions, LLC, Building 735-B, Aiken, SC 29808 (United States)

    2011-07-15

    A new rapid method for the determination of {sup 237}Np and Pu isotopes in soil and sediment samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for large soil samples. The new soil method utilizes an acid leaching method, iron/titanium hydroxide precipitation, a lanthanum fluoride soil matrix removal step, and a rapid column separation process with TEVA Resin. The large soil matrix is removed easily and rapidly using these two simple precipitations with high chemical recoveries and effective removal of interferences. Vacuum box technology and rapid flow rates are used to reduce analytical time.

  14. Microwave-assisted rapid synthesis of Fe{sub 2}O{sub 3}/ACF hybrid for high efficient As(V) removal

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Huiyun; Lv, Kangle; Du, Ying; Ye, Hengpeng; Du, Dongyun, E-mail: dydu666@mail.scuec.edu.cn

    2016-07-25

    In this paper, an efficient adsorbent, iron-modified activated carbon fiber (Fe{sub 2}O{sub 3}/ACF), was rapidly fabricated by microwave-assisted heating treatment strategy, which is used to remove As(V) from simulated wastewater. The adsorbent was characterized by scanning electron microscopy (SEM), TEM, N{sub 2} sorption, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The characterization results showed that rod-like Fe{sub 2}O{sub 3} particles in sizes of about 20 nm × 50 nm were homogeneously anchored on the surface of ACF. The goal of high As(V) removal efficiency was achieved with maximum adsorption capacity of 20.33 mg g{sup −1}. The effects of temperature on thermodynamics and kinetics of As(V) adsorption were systematically studied. It was found that the adsorption of As(V) on the surface of Fe{sub 2}O{sub 3}/ACF is an endothermic process with a standard enthalpy change (ΔH{sup 0}) of 24.79 kJ mol{sup −1}. Batch experimental result showed that almost all of the As(V) with initial concentration of 3.0 mg L{sup −1} can be removed in the presence of Fe{sub 2}O{sub 3}/ACF, where the residual As(V) in filtrate was less than 0.01 mg L{sup −1}, below the tolerance level of drinking water suggested by World Health Organization (WHO). The presence of salt such as NaCl, Na{sub 2}SO{sub 4}, and MgSO{sub 4} showed little effects on the adsorption of As(V), indicating the promising application of Fe{sub 2}O{sub 3}/ACF in industrial wastewater. - Highlights: • Fe{sub 2}O{sub 3}/ACF hybrid was rapidly fabricated using a microwave-assisted heating strategy. • Fe{sub 2}O{sub 3} nanorods in sizes of 20 × 50 nm were homogeneously anchored on the surface of ACF. • The maximum adsorption capacity of 20.33 mg g{sup −1} As (V) on Fe{sub 2}O{sub 3}/ACF was achieved. • The adsorption of As (V) is an endothermic process (ΔH{sup 0} = 24.79 kJ mol{sup −1}). • The presence of salt shows little effect on the adsorption of As (V).

  15. Soil classification basing on the spectral characteristics of topsoil samples

    Science.gov (United States)

    Liu, Huanjun; Zhang, Xiaokang; Zhang, Xinle

    2016-04-01

    Soil taxonomy plays an important role in soil utility and management, but China has only course soil map created based on 1980s data. New technology, e.g. spectroscopy, could simplify soil classification. The study try to classify soils basing on the spectral characteristics of topsoil samples. 148 topsoil samples of typical soils, including Black soil, Chernozem, Blown soil and Meadow soil, were collected from Songnen plain, Northeast China, and the room spectral reflectance in the visible and near infrared region (400-2500 nm) were processed with weighted moving average, resampling technique, and continuum removal. Spectral indices were extracted from soil spectral characteristics, including the second absorption positions of spectral curve, the first absorption vale's area, and slope of spectral curve at 500-600 nm and 1340-1360 nm. Then K-means clustering and decision tree were used respectively to build soil classification model. The results indicated that 1) the second absorption positions of Black soil and Chernozem were located at 610 nm and 650 nm respectively; 2) the spectral curve of the meadow is similar to its adjacent soil, which could be due to soil erosion; 3) decision tree model showed higher classification accuracy, and accuracy of Black soil, Chernozem, Blown soil and Meadow are 100%, 88%, 97%, 50% respectively, and the accuracy of Blown soil could be increased to 100% by adding one more spectral index (the first two vole's area) to the model, which showed that the model could be used for soil classification and soil map in near future.

  16. Classification of Clean and Dirty Pighouse Surfaces Based on Spectral Reflectance

    DEFF Research Database (Denmark)

    Blanke, Mogens; Braithwaite, Ian David; Zhang, Guo-Qiang

    2004-01-01

    of designing a vision based system to locate dirty areas and subsequently direct a cleaning robot to remove dirt. Novel results include the characterisation of the spectral reflectance of real surfaces and dirt in a pig house and the design of illumination to obtain discrimination of clean from dirty areas...

  17. [Analysis of software for identifying spectral line of laser-induced breakdown spectroscopy based on LabVIEW].

    Science.gov (United States)

    Hu, Zhi-yu; Zhang, Lei; Ma, Wei-guang; Yan, Xiao-juan; Li, Zhi-xin; Zhang, Yong-zhi; Wang, Le; Dong, Lei; Yin, Wang-bao; Jia, Suo-tang

    2012-03-01

    Self-designed identifying software for LIBS spectral line was introduced. Being integrated with LabVIEW, the soft ware can smooth spectral lines and pick peaks. The second difference and threshold methods were employed. Characteristic spectrum of several elements matches the NIST database, and realizes automatic spectral line identification and qualitative analysis of the basic composition of sample. This software can analyze spectrum handily and rapidly. It will be a useful tool for LIBS.

  18. Multiyear Downstream Response to Dam Removal on the White Salmon River, WA

    Science.gov (United States)

    Wilcox, A. C.; O'Connor, J. E.; Major, J. J.

    2017-12-01

    The 2011 removal of the 38 m tall Condit Dam on the White Salmon River, Washington was one of the largest dam removals to date, in terms of both dam height and sediment release. We examined the multiyear geomorphic response to this event, through 2015, including in a bedrock-confined canyon and in a less-confined, backwater-influenced pool reach near the river's mouth, to the large, rapid influx of fine reservoir sediment produced by the breach and to subsequent sediment transfer in the free-flowing White Salmon River. In the canyon reach, aggraded sediments were rapidly eroded from riffles, returning them toward pre-breach bed elevations within weeks, but pool aggradation persisted for longer. The downstream, less-confined reach transformed from a deep pool to a narrower pool-riffle channel with alternate bars; multiyear observations showed persistence of bars and of this new and distinct morphology. This downstream reach marks a rare case in post-dam removal channel response; in most dam removals, channels have rapidly reverted toward pre-removal morphology, as in the canyon reach here. Comparison of the multiyear geomorphic evolution of the White Salmon River to other recent large dam removals in the U.S. allows evaluation of the relative influences of antecedent channel morphology, post-breach hydrology, and dam removal style, as well as providing a basis for predicting responses to future dam removals.

  19. WE-FG-207B-12: Quantitative Evaluation of a Spectral CT Scanner in a Phantom Study: Results of Spectral Reconstructions

    International Nuclear Information System (INIS)

    Duan, X; Arbique, G; Guild, J; Anderson, J; Yagil, Y

    2016-01-01

    Purpose: To evaluate the quantitative image quality of spectral reconstructions of phantom data from a spectral CT scanner. Methods: The spectral CT scanner (IQon Spectral CT, Philips Healthcare) is equipped with a dual-layer detector and generates conventional 80-140 kVp images and variety of spectral reconstructions, e.g., virtual monochromatic (VM) images, virtual non-contrast (VNC) images, iodine maps, and effective atomic number (Z) images. A cylindrical solid water phantom (Gammex 472, 33 cm diameter and 5 cm thick) with iodine (2.0-20.0 mg I/ml) and calcium (50-600 mg/ml) rod inserts was scanned at 120 kVp and 27 mGy CTDIvol. Spectral reconstructions were evaluated by comparing image measurements with theoretical values calculated from nominal rod compositions provided by the phantom manufacturer. The theoretical VNC was calculated using water and iodine basis material decomposition, and the theoretical Z was calculated using two common methods, the chemical formula method (Z1) and the dual-energy ratio method (Z2). Results: Beam-hardening-like artifacts between high-attenuation calcium rods (≥300 mg/ml, >800 HU) influenced quantitative measurements, so the quantitative analysis was only performed on iodine rods using the images from the scan with all the calcium rods removed. The CT numbers of the iodine rods in the VM images (50∼150 keV) were close to theoretical values with average difference of 2.4±6.9 HU. Compared with theoretical values, the average difference for iodine concentration, VNC CT number and effective Z of iodine rods were −0.10±0.38 mg/ml, −0.1±8.2 HU, 0.25±0.06 (Z1) and −0.23±0.07 (Z2). Conclusion: The results indicate that the spectral CT scanner generates quantitatively accurate spectral reconstructions at clinically relevant iodine concentrations. Beam-hardening-like artifacts still exist when high-attenuation objects are present and their impact on patient images needs further investigation. YY is an employee of Philips

  20. WE-FG-207B-12: Quantitative Evaluation of a Spectral CT Scanner in a Phantom Study: Results of Spectral Reconstructions

    Energy Technology Data Exchange (ETDEWEB)

    Duan, X; Arbique, G; Guild, J; Anderson, J [UT Southwestern Medical Center, Dallas, TX (United States); Yagil, Y [Philips Healthcare, Haifa (Israel)

    2016-06-15

    Purpose: To evaluate the quantitative image quality of spectral reconstructions of phantom data from a spectral CT scanner. Methods: The spectral CT scanner (IQon Spectral CT, Philips Healthcare) is equipped with a dual-layer detector and generates conventional 80-140 kVp images and variety of spectral reconstructions, e.g., virtual monochromatic (VM) images, virtual non-contrast (VNC) images, iodine maps, and effective atomic number (Z) images. A cylindrical solid water phantom (Gammex 472, 33 cm diameter and 5 cm thick) with iodine (2.0-20.0 mg I/ml) and calcium (50-600 mg/ml) rod inserts was scanned at 120 kVp and 27 mGy CTDIvol. Spectral reconstructions were evaluated by comparing image measurements with theoretical values calculated from nominal rod compositions provided by the phantom manufacturer. The theoretical VNC was calculated using water and iodine basis material decomposition, and the theoretical Z was calculated using two common methods, the chemical formula method (Z1) and the dual-energy ratio method (Z2). Results: Beam-hardening-like artifacts between high-attenuation calcium rods (≥300 mg/ml, >800 HU) influenced quantitative measurements, so the quantitative analysis was only performed on iodine rods using the images from the scan with all the calcium rods removed. The CT numbers of the iodine rods in the VM images (50∼150 keV) were close to theoretical values with average difference of 2.4±6.9 HU. Compared with theoretical values, the average difference for iodine concentration, VNC CT number and effective Z of iodine rods were −0.10±0.38 mg/ml, −0.1±8.2 HU, 0.25±0.06 (Z1) and −0.23±0.07 (Z2). Conclusion: The results indicate that the spectral CT scanner generates quantitatively accurate spectral reconstructions at clinically relevant iodine concentrations. Beam-hardening-like artifacts still exist when high-attenuation objects are present and their impact on patient images needs further investigation. YY is an employee of Philips

  1. Development of a system for rapid discharge of spherical fuel elements as a diversitary afterheat removal system for pebble-bed HTR-type reactors

    International Nuclear Information System (INIS)

    Phlippen, P.W.

    1982-07-01

    Owing to its spherical fuel elements the pebble bed high temperature reactor provides the possibility to remove these fuel elements rapidly from the reactor for the purpose of after-heat removal and cooling in situations of danger and to collect them in easily cooled tanks. The paper investigates and represents fields of problems such as critically behaviour of core and fuel element collecting tanks, emission time of the core, thermodynamics in the vessel etc. by example of the PNP-500 reactor concept. A selection for the construction proposal was made from the performance possibilities of the three necessary main components prestressed-concrete vessel closure, fuel element guide and fuel element storage with cooling system. The proposal includes a prestressed concrete vessel closure opening by hydraulics as well as three annular fuel element storage modules cooled with the containment air by natural convection. (orig.) [de

  2. Suppressing carrier removal error in the Fourier transform method for interferogram analysis

    International Nuclear Information System (INIS)

    Fan, Qi; Yang, Hongru; Li, Gaoping; Zhao, Jianlin

    2010-01-01

    A new carrier removal method for interferogram analysis using the Fourier transform is presented. The proposed method can be used to suppress the carrier removal error as well as the spectral leakage error. First, the carrier frequencies are estimated with the spectral centroid of the up sidelobe of the apodized interferogram, and then the up sidelobe can be shifted to the origin in the frequency domain by multiplying the original interferogram by a constructed plane reference wave. The influence of the carrier frequencies without an integer multiple of the frequency interval and the window function for apodization of the interferogram can be avoided in our work. The simulation and experimental results show that this method is effective for phase measurement with a high accuracy from a single interferogram

  3. Evaluation of discrimination measures to characterize spectrally similar leaves of African Savannah trees

    CSIR Research Space (South Africa)

    Dudeni, N

    2009-08-01

    Full Text Available tree species. SDA builds a step-by-step model which evaluates the contribution of each spectral band with respect to the discriminatory power of the model. The discriminatory power of the model is measured by the Wilk’s lambda. A spectral band... therefore enters the model if it, according to the Wilk’s lambda criterion, contributes more to the discrimination of the tree species, while it is removed if it contributes least to the discriminatory power of the model. A discriminant model can generally...

  4. Image enhancement by spectral-error correction for dual-energy computed tomography.

    Science.gov (United States)

    Park, Kyung-Kook; Oh, Chang-Hyun; Akay, Metin

    2011-01-01

    Dual-energy CT (DECT) was reintroduced recently to use the additional spectral information of X-ray attenuation and aims for accurate density measurement and material differentiation. However, the spectral information lies in the difference between low and high energy images or measurements, so that it is difficult to acquire accurate spectral information due to amplification of high pixel noise in the resulting difference image. In this work, an image enhancement technique for DECT is proposed, based on the fact that the attenuation of a higher density material decreases more rapidly as X-ray energy increases. We define as spectral error the case when a pixel pair of low and high energy images deviates far from the expected attenuation trend. After analyzing the spectral-error sources of DECT images, we propose a DECT image enhancement method, which consists of three steps: water-reference offset correction, spectral-error correction, and anti-correlated noise reduction. It is the main idea of this work that makes spectral errors distributed like random noise over the true attenuation and suppressed by the well-known anti-correlated noise reduction. The proposed method suppressed noise of liver lesions and improved contrast between liver lesions and liver parenchyma in DECT contrast-enhanced abdominal images and their two-material decomposition.

  5. Aspiring to Spectral Ignorance in Earth Observation

    Science.gov (United States)

    Oliver, S. A.

    2016-12-01

    Enabling robust, defensible and integrated decision making in the Era of Big Earth Data requires the fusion of data from multiple and diverse sensor platforms and networks. While the application of standardised global grid systems provides a common spatial analytics framework that facilitates the computationally efficient and statistically valid integration and analysis of these various data sources across multiple scales, there remains the challenge of sensor equivalency; particularly when combining data from different earth observation satellite sensors (e.g. combining Landsat and Sentinel-2 observations). To realise the vision of a sensor ignorant analytics platform for earth observation we require automation of spectral matching across the available sensors. Ultimately, the aim is to remove the requirement for the user to possess any sensor knowledge in order to undertake analysis. This paper introduces the concept of spectral equivalence and proposes a methodology through which equivalent bands may be sourced from a set of potential target sensors through application of equivalence metrics and thresholds. A number of parameters can be used to determine whether a pair of spectra are equivalent for the purposes of analysis. A baseline set of thresholds for these parameters and how to apply them systematically to enable relation of spectral bands amongst numerous different sensors is proposed. The base unit for comparison in this work is the relative spectral response. From this input, determination of a what may constitute equivalence can be related by a user, based on their own conceptualisation of equivalence.

  6. Hole spectral functions in lightly doped quantum antiferromagnets

    Science.gov (United States)

    Kar, Satyaki; Manousakis, Efstratios

    2011-11-01

    We study the hole and magnon spectral functions as a function of hole doping in the two-dimensional t-J and t-t'-t''-J models working within the limits of spin-wave theory by linearizing the hole-spin-deviation interaction and by adapting the noncrossing approximation. We find that the staggered magnetization decreases rather rapidly with doping and it goes to zero at a few percent of hole concentration in both t-J and t-t'-t''-J models. Furthermore, our results show that the residue of the quasiparticle peak at G⃗=(±π/2,±π/2) decreases very rapidly with doping. We also find pockets centered at G⃗, (i) with an elliptical shape with large eccentricity along the antinodal direction in the case of the t-J model and (ii) with an almost circular shape in the case of the t-t'-t''-J model. Last, we show that the spectral intensity distribution in the doped antiferromagnet has a waterfall-like pattern along the nodal direction of the Brillouin zone, a feature that is also seen in angle-resolved photoemission spectroscopy measurements.

  7. Methodes spectrales paralleles et applications aux simulations de couches de melange compressibles

    OpenAIRE

    Male , Jean-Michel; Fezoui , Loula ,

    1993-01-01

    La resolution des equations de Navier-Stokes en methodes spectrales pour des ecoulements compressibles peut etre assez gourmande en temps de calcul. On etudie donc ici la parallelisation d'un tel algorithme et son implantation sur une machine massivement parallele, la connection-machine CM-2. La methode spectrale s'adapte bien aux exigences du parallelisme massif, mais l'un des outils de base de cette methode, la transformee de Fourier rapide (lorsqu'elle doit etre appliquee sur les deux dime...

  8. Citrus pectin derived porous carbons as a superior adsorbent toward removal of methylene blue

    International Nuclear Information System (INIS)

    Zhang, Wenlin; Zhang, Lian Ying; Zhao, Xi Juan; Zhou, Zhiqin

    2016-01-01

    An adsorbent, citrus pectin derived porous carbons with ultra-high adsorption capacity, rapid adsorption rate and good reusability toward removal of methylene blue, was synthesized by a facile zinc chloride activation approach in this study. The materials hold a great potential for treatment of dye wastewater. - Graphical abstract: Citrus pectin derived porous carbons with ultra-high adsorption capacity, rapid adsorption rate and good reusability toward methylene blue removal. - Highlights: • Citrus pectin derived porous carbons (CPPCs) were synthesized a facile zinc chloride activation approach. • CPPCs had abundant macro/meso/micropores for trapping MB molecules. • CPPCs exhibited ultrahigh adsorption capacity, rapid adsorption rate and good reusability toward removal of MB.

  9. Citrus pectin derived porous carbons as a superior adsorbent toward removal of methylene blue

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenlin [College of Horticulture and landscape Architecture, Southwest University, Chongqing 400716 (China); Zhang, Lian Ying [Institute for Clean Energy & Advanced Materials, Southwest University, Chongqing 400715 (China); Zhao, Xi Juan [College of Horticulture and landscape Architecture, Southwest University, Chongqing 400716 (China); Key Laboratory of Horticulture Science for Southern Mountainous Regions, Ministry of Education, Chongqing 400715 (China); Zhou, Zhiqin, E-mail: zhouzhiqin@swu.edu.cn [College of Horticulture and landscape Architecture, Southwest University, Chongqing 400716 (China); Key Laboratory of Horticulture Science for Southern Mountainous Regions, Ministry of Education, Chongqing 400715 (China)

    2016-11-15

    An adsorbent, citrus pectin derived porous carbons with ultra-high adsorption capacity, rapid adsorption rate and good reusability toward removal of methylene blue, was synthesized by a facile zinc chloride activation approach in this study. The materials hold a great potential for treatment of dye wastewater. - Graphical abstract: Citrus pectin derived porous carbons with ultra-high adsorption capacity, rapid adsorption rate and good reusability toward methylene blue removal. - Highlights: • Citrus pectin derived porous carbons (CPPCs) were synthesized a facile zinc chloride activation approach. • CPPCs had abundant macro/meso/micropores for trapping MB molecules. • CPPCs exhibited ultrahigh adsorption capacity, rapid adsorption rate and good reusability toward removal of MB.

  10. Rapid removal of bisphenol A on highly ordered mesoporous carbon.

    Science.gov (United States)

    Sui, Qian; Huang, Jun; Liu, Yousong; Chang, Xiaofeng; Ji, Guangbin; Deng, Shubo; Xie, Tao; Yu, Gang

    2011-01-01

    Bisphenol A (BPA) is of global concern due to its disruption of endocrine systems and ubiquity in the aquatic environment. It is important, therefore, that efforts are made to remove it from the aqueous phase. A novel adsorbent, mesoporous carbon CMK-3, prepared from hexagonal SBA-15 mesoporous silica was studied for BPA removal from aqueous phase, and compared with conventional powdered activated carbon (PAC). Characterization of CMK-3 by transmission electron microscopy (TEM), X-ray diffraction, and nitrogen adsorption indicated that prepared CMK-3 had an ordered mesoporous structure with a high specific surface area of 920 m2/g and a pore-size of about 4.9 nm. The adsorption of BPA on CMK-3 followed a pseudo second-order kinetic model. The kinetic constant was 0.00049 g/(mg x min), much higher than the adsorption of BPA on PAC. The adsorption isotherm fitted slightly better with the Freundlich model than the Langmuir model, and adsorption capacity decreased as temperature increased from 10 to 40 degrees C. No significant influence of pH on adsorption was observed at pH 3 to 9; however, adsorption capacity decreased dramatically from pH 9 to 13.

  11. Spectral and temporal cues for perception of material and action categories in impacted sound sources

    DEFF Research Database (Denmark)

    Hjortkjær, Jens; McAdams, Stephen

    2016-01-01

    In two experiments, similarity ratings and categorization performance with recorded impact sounds representing three material categories (wood, metal, glass) being manipulated by three different categories of action (drop, strike, rattle) were examined. Previous research focusing on single impact...... correlated with the pattern of confusion in categorization judgments. Listeners tended to confuse materials with similar spectral centroids, and actions with similar temporal centroids and onset densities. To confirm the influence of these different features, spectral cues were removed by applying...

  12. Spectral reconstruction for shifted-excitation Raman difference spectroscopy (SERDS).

    Science.gov (United States)

    Guo, Shuxia; Chernavskaia, Olga; Popp, Jürgen; Bocklitz, Thomas

    2018-08-15

    Fluorescence emission is one of the major obstacles to apply Raman spectroscopy in biological investigations. It is usually several orders more intense than Raman scattering and hampers further analysis. In cases where the fluorescence emission is too intense to be efficiently removed via routine mathematical baseline correction algorithms, an alternative approach is needed. One alternative approach is shifted-excitation Raman difference spectroscopy (SERDS), where two Raman spectra are recorded with two slightly different excitation wavelengths. Ideally, the fluorescence emission at the two excitations does not change while the Raman spectrum shifts according to the excitation wavelength. Hence the fluorescence is removed in the difference of the two recorded Raman spectra. For better interpretability a spectral reconstruction procedure is necessary to recover the fluorescence-free Raman spectrum. This is challenging due to the intensity variations between the two recorded Raman spectra caused by unavoidable experimental changes as well as the presence of noise. Existent approaches suffer from drawbacks like spectral resolution loss, fluorescence residual, and artefacts. In this contribution, we proposed a reconstruction method based on non-negative least squares (NNLS), where the intensity variations between the two measurements are utilized in the reconstruction model. The method achieved fluorescence-free reconstruction on three real-world SERDS datasets without significant information loss. Thereafter, we quantified the performance of the reconstruction based on artificial datasets from four aspects: reconstructed spectral resolution, precision of reconstruction, signal-to-noise-ratio (SNR), and fluorescence residual. The artificial datasets were constructed with varied Raman to fluorescence intensity ratio (RFIR), SNR, full-width at half-maximum (FWHM), excitation wavelength shift, and fluorescence variation between the two spectra. It was demonstrated that

  13. The detection of 'virtual' objects using echoes by humans: Spectral cues.

    Science.gov (United States)

    Rowan, Daniel; Papadopoulos, Timos; Archer, Lauren; Goodhew, Amanda; Cozens, Hayley; Lopez, Ricardo Guzman; Edwards, David; Holmes, Hannah; Allen, Robert

    2017-07-01

    Some blind people use echoes to detect discrete, silent objects to support their spatial orientation/navigation, independence, safety and wellbeing. The acoustical features that people use for this are not well understood. Listening to changes in spectral shape due to the presence of an object could be important for object detection and avoidance, especially at short range, although it is currently not known whether it is possible with echolocation-related sounds. Bands of noise were convolved with recordings of binaural impulse responses of objects in an anechoic chamber to create 'virtual objects', which were analysed and played to sighted and blind listeners inexperienced in echolocation. The sounds were also manipulated to remove cues unrelated to spectral shape. Most listeners could accurately detect hard flat objects using changes in spectral shape. The useful spectral changes for object detection occurred above approximately 3 kHz, as with object localisation. However, energy in the sounds below 3 kHz was required to exploit changes in spectral shape for object detection, whereas energy below 3 kHz impaired object localisation. Further recordings showed that the spectral changes were diminished by room reverberation. While good high-frequency hearing is generally important for echolocation, the optimal echo-generating stimulus will probably depend on the task. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  14. Information theory, spectral geometry, and quantum gravity.

    Science.gov (United States)

    Kempf, Achim; Martin, Robert

    2008-01-18

    We show that there exists a deep link between the two disciplines of information theory and spectral geometry. This allows us to obtain new results on a well-known quantum gravity motivated natural ultraviolet cutoff which describes an upper bound on the spatial density of information. Concretely, we show that, together with an infrared cutoff, this natural ultraviolet cutoff beautifully reduces the path integral of quantum field theory on curved space to a finite number of ordinary integrations. We then show, in particular, that the subsequent removal of the infrared cutoff is safe.

  15. SPAM- SPECTRAL ANALYSIS MANAGER (DEC VAX/VMS VERSION)

    Science.gov (United States)

    Solomon, J. E.

    1994-01-01

    The Spectral Analysis Manager (SPAM) was developed to allow easy qualitative analysis of multi-dimensional imaging spectrometer data. Imaging spectrometers provide sufficient spectral sampling to define unique spectral signatures on a per pixel basis. Thus direct material identification becomes possible for geologic studies. SPAM provides a variety of capabilities for carrying out interactive analysis of the massive and complex datasets associated with multispectral remote sensing observations. In addition to normal image processing functions, SPAM provides multiple levels of on-line help, a flexible command interpretation, graceful error recovery, and a program structure which can be implemented in a variety of environments. SPAM was designed to be visually oriented and user friendly with the liberal employment of graphics for rapid and efficient exploratory analysis of imaging spectrometry data. SPAM provides functions to enable arithmetic manipulations of the data, such as normalization, linear mixing, band ratio discrimination, and low-pass filtering. SPAM can be used to examine the spectra of an individual pixel or the average spectra over a number of pixels. SPAM also supports image segmentation, fast spectral signature matching, spectral library usage, mixture analysis, and feature extraction. High speed spectral signature matching is performed by using a binary spectral encoding algorithm to separate and identify mineral components present in the scene. The same binary encoding allows automatic spectral clustering. Spectral data may be entered from a digitizing tablet, stored in a user library, compared to the master library containing mineral standards, and then displayed as a timesequence spectral movie. The output plots, histograms, and stretched histograms produced by SPAM can be sent to a lineprinter, stored as separate RGB disk files, or sent to a Quick Color Recorder. SPAM is written in C for interactive execution and is available for two different

  16. Deconvolving X-ray spectral variability components in the Seyfert 1.5 NGC 3227

    International Nuclear Information System (INIS)

    Arévalo, P.; Markowitz, A.

    2014-01-01

    We present the variability analysis of a 100 ks XMM-Newton observation of the Seyfert 1.5 active galaxy, NGC 3227. The observation found NGC 3227 in a period where its hard power-law component displayed remarkably little long-term variability. This lucky event allows us to clearly observe a soft spectral component undergoing a large-amplitude but slow flux variation. Using combined spectral and timing analysis, we isolate two independent variable continuum components and characterize their behavior as a function of timescale. Rapid and coherent variations throughout the 0.2-10 keV band reveal a spectrally hard (photon index Γ ∼ 1.7-1.8) power law, dominating the observed variability on timescales of 30 ks and shorter. Another component produces coherent fluctuations in the 0.2-2 keV range and is much softer (Γ ∼ 3); it dominates the observed variability on timescales greater than 30 ks. Both components are viewed through the same absorbers identified in the time-averaged spectrum. The combined spectral and timing analysis breaks the degeneracy between models for the soft excess: it is consistent with a power-law or thermal Comptonized component but not with a blackbody or an ionized reflection component. We demonstrate that the rapid variability in NGC 3227 is intrinsic to continuum-emitting components and is not an effect of variable absorption.

  17. Microbial degradation of pesticides in rapid sand filters for treatment of drinking water

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen; Albrechtsen, Hans-Jørgen

    2014-01-01

    In Denmark drinking water supply is based on groundwater which is treated by aeration followed by filtration in rapid sand filters. Unfortunately pesticide contamination of the groundwater poses a threat to the water supply, since the simple treatment process at the waterworks is not considered...... to remove pesticides from the water phase and pesticides are detected in 24% of the active Danish waterworks wells. This study aimed at investigating the potential of microbial pesticide removal in rapid sand filters for drinking water treatment. Removal of the pesticides MCPP, bentazone, glyphosate...... and the degradation compound p-nitrophenol was investigated in the rapid sand filters at Islevbro and Sjælsø waterworks plant I and II. Microcosms were set up with sand from rapid sand filters, water and an initial pesticide concentration of 0.03-0.38 μg/L. In all the investigated waterworks the concentration...

  18. Removal of Thin Cirrus Path Radiances in the 0.4-1.0 micron Spectral Region Using the 1.375-micron Strong Water Vapor Absorption Channel

    Science.gov (United States)

    Gao, Bo-Cai; Kaufman, Yoram J.; Han, Wei; Wiscombe, Warren J.

    1998-01-01

    Through analysis of spectral imaging data acquired with the Airborne Visible Infrared Imaging Spectrometer (AVIRIS) from an ER-2 aircraft at 20 km altitude during several field programs, it was found that narrow channels near the center of the strong 1.38-micron water vapor band are very sensitive in detecting thin cirrus clouds. Based on this observation from AVIRIS data, a channel centered at 1.375 microns with a width of 30 nm was selected for the Moderate Resolution Imaging Spectrometer (MODIS) for remote sensing of cirrus clouds from space. The sensitivity of the 1.375-micron MODIS channel to detect thin cirrus clouds during the day time is expected to be one to two orders of magnitude better than the current infrared emission techniques. As a result, a larger fraction of the satellite data will likely be identified as containing cirrus clouds. In order to make better studies of surface reflectance properties, thin cirrus effects must be removed from satellite images. We have developed an empirical approach for removing/correcting thin cirrus effects in the 0.4 - 1.0 micron region using channels near 1.375 microns. This algorithm will be incorporated into the present MODIS atmospheric correction algorithms for ocean color and land applications and will yield improved MODIS atmospheric aerosol, land surface, and ocean color products.

  19. Superparamagnetic iron oxide coated on the surface of cellulose nanospheres for the rapid removal of textile dye under mild condition

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Yunfeng [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, and College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Qin, Zongyi, E-mail: phqin@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, and College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Liu, Yannan; Cheng, Miao; Qian, Pengfei [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, and College of Material Science and Engineering, Donghua University, Shanghai 201620 (China); Wang, Qian, E-mail: drwangqian23@163.com [Department of Orthopaedics, Shanghai First People' s Hospital, Shanghai Jiaotong University, 100 Haining Road, Hongkou District, Shanghai 200080 (China); Zhu, Meifang [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, and College of Material Science and Engineering, Donghua University, Shanghai 201620 (China)

    2015-12-01

    Graphical abstract: - Highlights: • Anchoring superparamagnetic iron oxide on the surface of cellulose nanospheres as magnetically recyclable nanocatalys. • Achieving highly efficient Fenton-like reaction on the surface of composite nanospheres for rapid removal of textile dye. • Reaching nearly 98.0% degradation of Navy blue within 5 min under mild condition. - Abstract: Magnetic composite nanoparticles (MNPs) were prepared by anchoring iron oxide (Fe{sub 3}O{sub 4}) on the surface of carboxyl cellulose nanospheres through a facile chemical co-precipitation method. The as-prepared MNPs were characterized by atomic force microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, wide-angle X-ray diffraction measurement, thermal gravity analysis and vibrating sample magnetometry. These MNPs were of a generally spherical shape with a narrow size distribution, and exhibited superparamagnetic behaviors with high saturation magnetization. High efficient removal of Navy blue in aqueous solution was demonstrated at room temperature in a Fenton-like system containing the MNPs and H{sub 2}O{sub 2}, which benefited from small particle size, large surface area, high chemical activity, and good dispersibility of the MNPs. The removal efficiency of Navy blue induced by the MNPs prepared at a weight ratio of cellulose to iron of 1:2 were 90.6% at the first minute of the degradation reaction, and 98.0% for 5 min. Furthermore, these MNPs could be efficiently recycled and reused by using an external magnetic field. The approach presented in this paper promotes the use of renewable natural resources as templates for the preparation and stabilization of various inorganic nanomaterials for the purpose of catalysis, magnetic resonance imaging, biomedical and other potential applications.

  20. Evaluation of virus removal efficiency of coagulation-sedimentation and rapid sand filtration processes in a drinking water treatment plant in Bangkok, Thailand.

    Science.gov (United States)

    Asami, Tatsuya; Katayama, Hiroyuki; Torrey, Jason Robert; Visvanathan, Chettiyappan; Furumai, Hiroaki

    2016-09-15

    In order to properly assess and manage the risk of infection by enteric viruses in tap water, virus removal efficiency should be evaluated quantitatively for individual processes in actual drinking water treatment plants (DWTPs); however, there have been only a few studies due to technical difficulties in quantifying low virus concentration in water samples. In this study, the removal efficiency of indigenous viruses was evaluated for coagulation-sedimentation (CS) and rapid sand filtration (RSF) processes in a DWTP in Bangkok, Thailand by measuring the concentration of viruses before and after treatment processes using real-time polymerase chain reaction (qPCR). Water samples were collected and concentrated from raw source water, after CS, and after RSF, and inhibitory substances in water samples were reduced by use of a hydrophobic resin (DAX-8). Pepper mild mottle virus (PMMoV) and JC polyomavirus (JC PyV) were found to be highly prevalent in raw waters, with concentrations of 10(2.88 ± 0.35) and 10(3.06 ± 0.42) copies/L (geometric mean ± S.D.), respectively. Step-wise removal efficiencies were calculated for individual processes, with some variation observed between wet and dry seasons. During the wet season, PMMoV was removed less by CS and more by RSF on average (0.40 log10 vs 1.26 log10, respectively), while the reverse was true for JC PyV (1.91 log10 vs 0.49 log10, respectively). Both viruses were removed similarly during the dry season, with CS removing the most virus (PMMoV, 1.61 log10 and 0.78 log10; JC PyV, 1.70 log10, and 0.59 log10; CS and RSF, respectively). These differences between seasons were potentially due to variations in raw water quality and the characteristics of the viruses themselves. These results suggest that PMMoV and JC PyV, which are more prevalent in environmental waters than the other enteric viruses evaluated in this study, could be useful in determining viral fate for the risk management of viruses in water treatment

  1. Rapid detection of benzoyl peroxide in wheat flour by using Raman scattering spectroscopy

    Science.gov (United States)

    Zhao, Juan; Peng, Yankun; Chao, Kuanglin; Qin, Jianwei; Dhakal, Sagar; Xu, Tianfeng

    2015-05-01

    Benzoyl peroxide is a common flour additive that improves the whiteness of flour and the storage properties of flour products. However, benzoyl peroxide adversely affects the nutritional content of flour, and excess consumption causes nausea, dizziness, other poisoning, and serious liver damage. This study was focus on detection of the benzoyl peroxide added in wheat flour. A Raman scattering spectroscopy system was used to acquire spectral signal from sample data and identify benzoyl peroxide based on Raman spectral peak position. The optical devices consisted of Raman spectrometer and CCD camera, 785 nm laser module, optical fiber, prober, and a translation stage to develop a real-time, nondestructive detection system. Pure flour, pure benzoyl peroxide and different concentrations of benzoyl peroxide mixed with flour were prepared as three sets samples to measure the Raman spectrum. These samples were placed in the same type of petri dish to maintain a fixed distance between the Raman CCD and petri dish during spectral collection. The mixed samples were worked by pretreatment of homogenization and collected multiple sets of data of each mixture. The exposure time of this experiment was set at 0.5s. The Savitzky Golay (S-G) algorithm and polynomial curve-fitting method was applied to remove the fluorescence background from the Raman spectrum. The Raman spectral peaks at 619 cm-1, 848 cm-1, 890 cm-1, 1001 cm-1, 1234 cm-1, 1603cm-1, 1777cm-1 were identified as the Raman fingerprint of benzoyl peroxide. Based on the relationship between the Raman intensity of the most prominent peak at around 1001 cm-1 and log values of benzoyl peroxide concentrations, the chemical concentration prediction model was developed. This research demonstrated that Raman detection system could effectively and rapidly identify benzoyl peroxide adulteration in wheat flour. The experimental result is promising and the system with further modification can be applicable for more products in near

  2. The morphodynamics of sediment movement through a reservoir during dam removal

    OpenAIRE

    Bromley, Chris

    2008-01-01

    Dam removal has recently emerged as a growing trend in river rehabilitation in the United States. The rate of dam removal has been increasing rapidly since 2000, but is doing so with large gaps in our understanding of how the fluvial system will respond to this disturbance. Most of the structures removed to date have been relatively small and, in the vast majority of cases, have not received any pre- or post-removal monitoring. Very few large structures have been removed but, when such remova...

  3. Measurement of 90Sr radioactivity in a rapid method of strontium estimation by solvent extraction with dicarbollides

    International Nuclear Information System (INIS)

    Svoboda, K.; Kyrs, M.

    1994-01-01

    The application of liquid scintillation counting to the measurement of 90 Sr radioactivity was studied, using a previously published rapid method of strontium separation, based on solvent extraction with a solution of cobalt dicarbollide and Slovafol 909 in a nitrobenzene-carbon tetrachloride mixture and subsequent stripping of strontium with a 0.15 M Chelaton IV (CDTA) solution at pH 10.2. With liquid scintillation counting, a more efficient elimination of the effect of 90 Y β-activity on 90 Sr counting is possible than when measuring the evaporated aliquot with the use of a solid scintillator. The adverse effect of traces of dicarbollide, nitrobenzene, and CCl 4 passed over in the aqueous 90 Sr solution prepared for counting, is caused by the (poorly reproducible) shift of the 90 Sr + 90 Y β-radiation spectral curve towards lower energies, the so-called quenching. The shift is independent of the aqueous phase concentration of the organic compounds mentioned. They can be removed by shaking the aqueous reextract with an equal volume of octanol or amyl acetate so that the undesirable spectral shift does not occur. No loss of strontium was found in this washing procedure. (author) 2 tabs., 6 figs., 5 refs

  4. Understanding Soliton Spectral Tunneling as a Spectral Coupling Effect

    DEFF Research Database (Denmark)

    Guo, Hairun; Wang, Shaofei; Zeng, Xianglong

    2013-01-01

    Soliton eigenstate is found corresponding to a dispersive phase profile under which the soliton phase changes induced by the dispersion and nonlinearity are instantaneously counterbalanced. Much like a waveguide coupler relying on a spatial refractive index profile that supports mode coupling...... between channels, here we suggest that the soliton spectral tunneling effect can be understood supported by a spectral phase coupler. The dispersive wave number in the spectral domain must have a coupler-like symmetric profile for soliton spectral tunneling to occur. We show that such a spectral coupler...

  5. Enhanced Al and Zn removal from coal-mine drainage during rapid oxidation and precipitation of Fe oxides at near-neutral pH

    Science.gov (United States)

    Burrows, Jill E.; Cravotta, Charles A.; Peters, Stephen C.

    2017-01-01

    Net-alkaline, anoxic coal-mine drainage containing ∼20 mg/L FeII and ∼0.05 mg/L Al and Zn was subjected to parallel batch experiments: control, aeration (Aer 1 12.6 mL/s; Aer 2 16.8 mL/s; Aer 3 25.0 mL/s), and hydrogen peroxide (H2O2) to test the hypothesis that aeration increases pH, FeII oxidation, hydrous FeIII oxide (HFO) formation, and trace-metal removal through adsorption and coprecipitation with HFO. During 5.5-hr field experiments, pH increased from 6.4 to 6.7, 7.1, 7.6, and 8.1 for the control, Aer 1, Aer 2, and Aer 3, respectively, but decreased to 6.3 for the H2O2 treatment. Aeration accelerated removal of dissolved CO2, Fe, Al, and Zn. In Aer 3, dissolved Al was completely removed within 1 h, but increased to ∼20% of the initial concentration after 2.5 h when pH exceeded 7.5. H2O2 promoted rapid removal of all dissolved Fe and Al, and 13% of dissolved Zn.Kinetic modeling with PHREEQC simulated effects of aeration on pH, CO2, Fe, Zn, and Al. Aeration enhanced Zn adsorption by increasing pH and HFO formation while decreasing aqueous CO2 available to form ZnCO30 and Zn(CO3)22− at high pH. Al concentrations were inconsistent with solubility control by Al minerals or Al-containing HFO, but could be simulated by adsorption on HFO at pH oxidation with pH adjustment to ∼7.5 could be effective for treating high-Fe and moderate-Zn concentrations, whereas chemical oxidation without pH adjustment may be effective for treating high-Fe and moderate-Al concentrations.

  6. A Study of Spectral Integration and Normalization in NMR-based Metabonomic Analyses

    Energy Technology Data Exchange (ETDEWEB)

    Webb-Robertson, Bobbie-Jo M.; Lowry, David F.; Jarman, Kristin H.; Harbo, Sam J.; Meng, Quanxin; Fuciarelli, Alfred F.; Pounds, Joel G.; Lee, Monica T.

    2005-09-15

    Metabonomics involves the quantitation of the dynamic multivariate metabolic response of an organism to a pathological event or genetic modification (Nicholson, Lindon and Holmes, 1999). The analysis of these data involves the use of appropriate multivariate statistical methods. Exploratory Data Analysis (EDA) linear projection methods, primarily Principal Component Analysis (PCA), have been documented as a valuable pattern recognition technique for 1H NMR spectral data (Brindle et al., 2002, Potts et al., 2001, Robertson et al., 2000, Robosky et al., 2002). Prior to PCA the raw data is typically processed through four steps; (1) baseline correction, (2) endogenous peak removal, (3) integration over spectral regions to reduce the number of variables, and (4) normalization. The effect of the size of spectral integration regions and normalization has not been well studied. We assess the variability structure and classification accuracy on two distinctly different datasets via PCA and a leave-one-out cross-validation approach under two normalization approaches and an array of spectral integration regions. This study indicates that independent of the normalization method the classification accuracy achieved from metabonomic studies is not highly sensitive to the size of the spectral integration region. Additionally, both datasets scaled to mean zero and unity variance (auto-scaled) has higher variability within classification accuracy over spectral integration window widths than data scaled to the total intensity of the spectrum.

  7. Spectral anomaly methods for aerial detection using KUT nuisance rejection

    International Nuclear Information System (INIS)

    Detwiler, R.S.; Pfund, D.M.; Myjak, M.J.; Kulisek, J.A.; Seifert, C.E.

    2015-01-01

    This work discusses the application and optimization of a spectral anomaly method for the real-time detection of gamma radiation sources from an aerial helicopter platform. Aerial detection presents several key challenges over ground-based detection. For one, larger and more rapid background fluctuations are typical due to higher speeds, larger field of view, and geographically induced background changes. As well, the possible large altitude or stand-off distance variations cause significant steps in background count rate as well as spectral changes due to increased gamma-ray scatter with detection at higher altitudes. The work here details the adaptation and optimization of the PNNL-developed algorithm Nuisance-Rejecting Spectral Comparison Ratios for Anomaly Detection (NSCRAD), a spectral anomaly method previously developed for ground-based applications, for an aerial platform. The algorithm has been optimized for two multi-detector systems; a NaI(Tl)-detector-based system and a CsI detector array. The optimization here details the adaptation of the spectral windows for a particular set of target sources to aerial detection and the tailoring for the specific detectors. As well, the methodology and results for background rejection methods optimized for the aerial gamma-ray detection using Potassium, Uranium and Thorium (KUT) nuisance rejection are shown. Results indicate that use of a realistic KUT nuisance rejection may eliminate metric rises due to background magnitude and spectral steps encountered in aerial detection due to altitude changes and geographically induced steps such as at land–water interfaces

  8. The spectral changes of deforestation in the Brazilian tropical savanna.

    Science.gov (United States)

    Trancoso, Ralph; Sano, Edson E; Meneses, Paulo R

    2015-01-01

    The Cerrado is a biome in Brazil that is experiencing the most rapid loss in natural vegetation. The objective of this study was to analyze the changes in the spectral response in the red, near infrared (NIR), middle infrared (MIR), and normalized difference vegetation index (NDVI) when native vegetation in the Cerrado is deforested. The test sites were regions of the Cerrado located in the states of Bahia, Minas Gerais, and Mato Grosso. For each region, a pair of Landsat Thematic Mapper (TM) scenes from 2008 (before deforestation) and 2009 (after deforestation) was compared. A set of 1,380 samples of deforested polygons and an equal number of samples of native vegetation have their spectral properties statistically analyzed. The accuracy of deforestation detections was also evaluated using high spatial resolution imagery. Results showed that the spectral data of deforested areas and their corresponding native vegetation were statistically different. The red band showed the highest difference between the reflectance data from deforested areas and native vegetation, while the NIR band showed the lowest difference. A consistent pattern of spectral change when native vegetation in the Cerrado is deforested was identified regardless of the location in the biome. The overall accuracy of deforestation detections was 97.75%. Considering both the marked pattern of spectral changes and the high deforestation detection accuracy, this study suggests that deforestation in Cerrado can be accurately monitored, but a strong seasonal and spatial variability of spectral changes might be expected.

  9. Techniques for Handling and Removal of Spectral Channels in Fourier Transform Synchrotron-Based Spectra

    International Nuclear Information System (INIS)

    Ibrahim, Amr; Predoi-Cross, Adriana; Teillet, Philippe M.

    2010-01-01

    Channel spectra are a big problem for those attempting to use synchrotron-based Fourier transform spectra for spectral lineshape studies. Due to the layout of the optical system at the CLS far-infrared beamline, the synchrotron beam undergoes unavoidable multiple reflections on the steering mirrors, beam splitter, several sets of windows, and filters. We present a method for eliminating channel spectra and compare the results of our technique with other methods available in the literature.

  10. Rapid characterization of transgenic and non-transgenic soybean oils by chemometric methods using NIR spectroscopy

    Science.gov (United States)

    Luna, Aderval S.; da Silva, Arnaldo P.; Pinho, Jéssica S. A.; Ferré, Joan; Boqué, Ricard

    Near infrared (NIR) spectroscopy and multivariate classification were applied to discriminate soybean oil samples into non-transgenic and transgenic. Principal Component Analysis (PCA) was applied to extract relevant features from the spectral data and to remove the anomalous samples. The best results were obtained when with Support Vectors Machine-Discriminant Analysis (SVM-DA) and Partial Least Squares-Discriminant Analysis (PLS-DA) after mean centering plus multiplicative scatter correction. For SVM-DA the percentage of successful classification was 100% for the training group and 100% and 90% in validation group for non transgenic and transgenic soybean oil samples respectively. For PLS-DA the percentage of successful classification was 95% and 100% in training group for non transgenic and transgenic soybean oil samples respectively and 100% and 80% in validation group for non transgenic and transgenic respectively. The results demonstrate that NIR spectroscopy can provide a rapid, nondestructive and reliable method to distinguish non-transgenic and transgenic soybean oils.

  11. Spatial variability of oceanic phycoerythrin spectral types derived from airborne laser-induced fluorescence emissions

    Science.gov (United States)

    Hoge, Frank E.; Wright, C. Wayne; Kana, Todd M.; Swift, Robert N.; Yungel, James K.

    1998-07-01

    We report spatial variability of oceanic phycoerythrin spectral types detected by means of a blue spectral shift in airborne laser-induced fluorescence emission. The blue shift of the phycoerythrobilin fluorescence is known from laboratory studies to be induced by phycourobilin chromophore substitution at phycoerythrobilin chromophore sites in some strains of phycoerythrin-containing marine cyanobacteria. The airborne 532-nm laser-induced phycoerythrin fluorescence of the upper oceanic volume showed distinct segregation of cyanobacterial chromophore types in a flight transect from coastal water to the Sargasso Sea in the western North Atlantic. High phycourobilin levels were restricted to the oceanic (oligotrophic) end of the flight transect, in agreement with historical ship findings. These remotely observed phycoerythrin spectral fluorescence shifts have the potential to permit rapid, wide-area studies of the spatial variability of spectrally distinct cyanobacteria, especially across interfacial regions of coastal and oceanic water masses. Airborne laser-induced phytoplankton spectral fluorescence observations also further the development of satellite algorithms for passive detection of phytoplankton pigments. Optical modifications to the NASA Airborne Oceanographic Lidar are briefly described that permitted observation of the fluorescence spectral shifts.

  12. Piecewise spectrally band-pass for compressive coded aperture spectral imaging

    International Nuclear Information System (INIS)

    Qian Lu-Lu; Lü Qun-Bo; Huang Min; Xiang Li-Bin

    2015-01-01

    Coded aperture snapshot spectral imaging (CASSI) has been discussed in recent years. It has the remarkable advantages of high optical throughput, snapshot imaging, etc. The entire spatial-spectral data-cube can be reconstructed with just a single two-dimensional (2D) compressive sensing measurement. On the other hand, for less spectrally sparse scenes, the insufficiency of sparse sampling and aliasing in spatial-spectral images reduce the accuracy of reconstructed three-dimensional (3D) spectral cube. To solve this problem, this paper extends the improved CASSI. A band-pass filter array is mounted on the coded mask, and then the first image plane is divided into some continuous spectral sub-band areas. The entire 3D spectral cube could be captured by the relative movement between the object and the instrument. The principle analysis and imaging simulation are presented. Compared with peak signal-to-noise ratio (PSNR) and the information entropy of the reconstructed images at different numbers of spectral sub-band areas, the reconstructed 3D spectral cube reveals an observable improvement in the reconstruction fidelity, with an increase in the number of the sub-bands and a simultaneous decrease in the number of spectral channels of each sub-band. (paper)

  13. Method for rapidly determining a pulp kappa number using spectrophotometry

    Science.gov (United States)

    Chai, Xin-Sheng; Zhu, Jun Yong

    2002-01-01

    A system and method for rapidly determining the pulp kappa number through direct measurement of the potassium permanganate concentration in a pulp-permanganate solution using spectrophotometry. Specifically, the present invention uses strong acidification to carry out the pulp-permanganate oxidation reaction in the pulp-permanganate solution to prevent the precipitation of manganese dioxide (MnO.sub.2). Consequently, spectral interference from the precipitated MnO.sub.2 is eliminated and the oxidation reaction becomes dominant. The spectral intensity of the oxidation reaction is then analyzed to determine the pulp kappa number.

  14. USGS Digital Spectral Library splib06a

    Science.gov (United States)

    Clark, Roger N.; Swayze, Gregg A.; Wise, Richard A.; Livo, K. Eric; Hoefen, Todd M.; Kokaly, Raymond F.; Sutley, Stephen J.

    2007-01-01

    ), one simply needs a diagnostic absorption band. The mapping system uses continuum-removed reference spectral features fitted to features in observed spectra. Spectral features for such algorithms can be obtained from a spectrum of a sample containing large amounts of contaminants, including those that add other spectral features, as long as the shape of the diagnostic feature of interest is not modified. If, however, the data are needed for radiative transfer models to derive mineral abundances from reflectance spectra, then completely uncontaminated spectra are required. This library contains spectra that span a range of quality, with purity indicators to flag spectra for (or against) particular uses. Acquiring spectral measurements and performing sample characterizations for this library has taken about 15 person-years of effort. Software to manage the library and provide scientific analysis capability is provided (Clark, 1980, 1993). A personal computer (PC) reader for the library is also available (Livo and others, 1993). The program reads specpr binary files (Clark, 1980, 1993) and plots spectra. Another program that reads the specpr format is written in IDL (Kokaly, 2005). In our view, an ideal spectral library consists of samples covering a very wide range of materials, has large wavelength range with very high precision, and has enough sample analyses and documentation to establish the quality of the spectra. Time and available resources limit what can be achieved. Ideally, for each mineral, the sample analysis would include X-ray diffraction (XRD), electron microprobe (EM) or X-ray fluorescence (XRF), and petrographic microscopic analyses. For some minerals, such as iron oxides, additional analyses such as Mossbauer would be helpful. We have found that to make the basic spectral measurements, provide XRD, EM or XRF analyses, and microscopic analyses, document the results, and complete an entry of one spectral library sample, all takes about

  15. [An Improved Spectral Quaternion Interpolation Method of Diffusion Tensor Imaging].

    Science.gov (United States)

    Xu, Yonghong; Gao, Shangce; Hao, Xiaofei

    2016-04-01

    Diffusion tensor imaging(DTI)is a rapid development technology in recent years of magnetic resonance imaging.The diffusion tensor interpolation is a very important procedure in DTI image processing.The traditional spectral quaternion interpolation method revises the direction of the interpolation tensor and can preserve tensors anisotropy,but the method does not revise the size of tensors.The present study puts forward an improved spectral quaternion interpolation method on the basis of traditional spectral quaternion interpolation.Firstly,we decomposed diffusion tensors with the direction of tensors being represented by quaternion.Then we revised the size and direction of the tensor respectively according to different situations.Finally,we acquired the tensor of interpolation point by calculating the weighted average.We compared the improved method with the spectral quaternion method and the Log-Euclidean method by the simulation data and the real data.The results showed that the improved method could not only keep the monotonicity of the fractional anisotropy(FA)and the determinant of tensors,but also preserve the tensor anisotropy at the same time.In conclusion,the improved method provides a kind of important interpolation method for diffusion tensor image processing.

  16. Effects of dynamic operating conditions on nitrification in biological rapid sand filters for drinking water treatment

    DEFF Research Database (Denmark)

    Lee, Carson Odell; Boe-Hansen, Rasmus; Musovic, Sanin

    2014-01-01

    Biological rapid sand filters are often used to remove ammonium from groundwater for drinking water supply. They often operate under dynamic substrate and hydraulic loading conditions, which can lead to increased levels of ammonium and nitrite in the effluent. To determine the maximum nitrification...... operating conditions. The ammonium removal rate of the filter was determined by the ammonium loading rate, but was independent of both the flow and influent ammonium concentration individually. Ammonia-oxidizing bacteria and archaea were almost equally abundant in the filter. Both ammonium removal...... rates and safe operating windows of rapid sand filters, a pilot scale rapid sand filter was used to test short-term increased ammonium loads, set by varying either influent ammonium concentrations or hydraulic loading rates. Ammonium and iron (flock) removal were consistent between the pilot...

  17. ULTRAVIOLET RAMAN SPECTRAL SIGNATURE ACQUISITION: UV RAMAN SPECTRAL FINGERPRINTS.

    Energy Technology Data Exchange (ETDEWEB)

    SEDLACEK,III, A.J.FINFROCK,C.

    2002-09-01

    As a member of the science-support part of the ITT-lead LISA development program, BNL is tasked with the acquisition of UV Raman spectral fingerprints and associated scattering cross-sections for those chemicals-of-interest to the program's sponsor. In support of this role, the present report contains the first installment of UV Raman spectral fingerprint data on the initial subset of chemicals. Because of the unique nature associated with the acquisition of spectral fingerprints for use in spectral pattern matching algorithms (i.e., CLS, PLS, ANN) great care has been undertaken to maximize the signal-to-noise and to minimize unnecessary spectral subtractions, in an effort to provide the highest quality spectral fingerprints. This report is divided into 4 sections. The first is an Experimental section that outlines how the Raman spectra are performed. This is then followed by a section on Sample Handling. Following this, the spectral fingerprints are presented in the Results section where the data reduction process is outlined. Finally, a Photographs section is included.

  18. Regional estimation of savanna grass nitrogen using the red-edge band of the RapidEye sensor

    CSIR Research Space (South Africa)

    Ramoelo, Abel

    2012-10-01

    Full Text Available recent high resolution spaceborne multispectral sensor (i.e. RapidEye) in the Kruger National Park (KNP) and its surrounding areas, South Africa. The RapidEyesensor contains five spectral bands in the visible-to-near infrared (VNIR), including a red...

  19. The rapid decline of the prompt emission in Gamma-Ray Bursts

    CERN Document Server

    Dado, Shlomo; De Rújula, Alvaro

    2008-01-01

    Many gamma ray bursts (GRBs) have been observed with the Burst-Alert and X-Ray telescopes of the SWIFT satellite. The successive `pulses' of these GRBs end with a fast decline and a fast spectral softening, until they are overtaken by another pulse, or the last pulse's decline is overtaken by a less rapidly-varying `afterglow'. The fast decline-phase has been attributed, in the standard fireball model of GRBs, to `high-latitude' synchrotron emission from a collision of two conical shells. This interpretation does not agree with the observed spectral softening. The temporal behaviour and the spectral evolution during the fast-decline phase agree with the predictions of the cannonball model of GRBs.

  20. Littoral Assessment of Mine Burial Signatures (LAMBS) buried land mine/background spectral signature analyses

    Science.gov (United States)

    Kenton, A.C.; Geci, D.M.; Ray, K.J.; Thomas, C.M.; Salisbury, J.W.; Mars, J.C.; Crowley, J.K.; Witherspoon, N.H.; Holloway, J.H.; Harmon R.S.Broach J.T.Holloway, Jr. J.H.

    2004-01-01

    The objective of the Office of Naval Research (ONR) Rapid Overt Reconnaissance (ROR) program and the Airborne Littoral Reconnaissance Technologies (ALRT) project's LAMBS effort is to determine if electro-optical spectral discriminants exist that are useful for the detection of land mines in littoral regions. Statistically significant buried mine overburden and background signature data were collected over a wide spectral range (0.35 to 14 ??m) to identify robust spectral features that might serve as discriminants for new airborne sensor concepts. LAMBS has expanded previously collected databases to littoral areas - primarily dry and wet sandy soils - where tidal, surf, and wind conditions can severely modify spectral signatures. At AeroSense 2003, we reported completion of three buried mine collections at an inland bay, Atlantic and Gulf of Mexico beach sites.1 We now report LAMBS spectral database analyses results using metrics which characterize the detection performance of general types of spectral detection algorithms. These metrics include mean contrast, spectral signal-to-clutter, covariance, information content, and spectral matched filter analyses. Detection performance of the buried land mines was analyzed with regard to burial age, background type, and environmental conditions. These analyses considered features observed due to particle size differences, surface roughness, surface moisture, and compositional differences.

  1. The Python Spectral Analysis Tool (PySAT): A Powerful, Flexible, Preprocessing and Machine Learning Library and Interface

    Science.gov (United States)

    Anderson, R. B.; Finch, N.; Clegg, S. M.; Graff, T. G.; Morris, R. V.; Laura, J.; Gaddis, L. R.

    2017-12-01

    Machine learning is a powerful but underutilized approach that can enable planetary scientists to derive meaningful results from the rapidly-growing quantity of available spectral data. For example, regression methods such as Partial Least Squares (PLS) and Least Absolute Shrinkage and Selection Operator (LASSO), can be used to determine chemical concentrations from ChemCam and SuperCam Laser-Induced Breakdown Spectroscopy (LIBS) data [1]. Many scientists are interested in testing different spectral data processing and machine learning methods, but few have the time or expertise to write their own software to do so. We are therefore developing a free open-source library of software called the Python Spectral Analysis Tool (PySAT) along with a flexible, user-friendly graphical interface to enable scientists to process and analyze point spectral data without requiring significant programming or machine-learning expertise. A related but separately-funded effort is working to develop a graphical interface for orbital data [2]. The PySAT point-spectra tool includes common preprocessing steps (e.g. interpolation, normalization, masking, continuum removal, dimensionality reduction), plotting capabilities, and capabilities to prepare data for machine learning such as creating stratified folds for cross validation, defining training and test sets, and applying calibration transfer so that data collected on different instruments or under different conditions can be used together. The tool leverages the scikit-learn library [3] to enable users to train and compare the results from a variety of multivariate regression methods. It also includes the ability to combine multiple "sub-models" into an overall model, a method that has been shown to improve results and is currently used for ChemCam data [4]. Although development of the PySAT point-spectra tool has focused primarily on the analysis of LIBS spectra, the relevant steps and methods are applicable to any spectral data. The

  2. Measurement of spectral sea ice albedo at Qaanaaq fjord in northwest Greenland

    Science.gov (United States)

    Tanikawa, T.

    2017-12-01

    The spectral albedos of sea ice were measured at Qaanaaq fjord in northwest Greenland. Spectral measurements were conducted for sea ice covered with snow and sea ice without snow where snow was artificially removed around measurement point. Thickness of the sea ice was approximately 1.3 m with 5 cm of snow over the sea ice. The measurements show that the spectral albedos of the sea ice with snow were lower than those of natural pure snow especially in the visible regions though the spectral shapes were similar to each other. This is because the spectral albedos in the visible region have information of not only the snow but also the sea ice under the snow. The spectral albedos of the sea ice without the snow were approximately 0.4 - 0.5 in the visible region, 0.05-0.25 in the near-infrared region and almost constant of approximately 0.05 in the region of 1500 - 2500 nm. In the visible region, it would be due to multiple scattering by an air bubble within the sea ice. In contrast, in the near-infrared and shortwave infrared wavelengths, surface reflection at the sea ice surface would be dominant. Since a light absorption by the ice in these regions is relatively strong comparing to the visible region, the light could not be penetrated deeply within the sea ice, resulting that surface reflection based on Fresnel reflection would be dominant. In this presentation we also show the results of comparison between the radiative transfer calculation and spectral measurement data.

  3. Rapid removal of uranium from aqueous solutions using magnetic Fe3O4@SiO2 composite particles.

    Science.gov (United States)

    Fan, Fang-Li; Qin, Zhi; Bai, Jing; Rong, Wei-Dong; Fan, Fu-You; Tian, Wei; Wu, Xiao-Lei; Wang, Yang; Zhao, Liang

    2012-04-01

    Rapid removal of U(VI) from aqueous solutions was investigated using magnetic Fe(3)O(4)@SiO(2) composite particles as the novel adsorbent. Batch experiments were conducted to study the effects of initial pH, amount of adsorbent, shaking time and initial U(VI) concentrations on uranium sorption efficiency as well as the desorbing of U(VI). The sorption of uranium on Fe(3)O(4)@SiO(2) composite particles was pH-dependent, and the optimal pH was 6.0. In kinetics studies, the sorption equilibrium can be reached within 180 min, and the experimental data were well fitted by the pseudo-second-order model, and the equilibrium sorption capacities calculated by the model were almost the same as those determined by experiments. The Langmuir sorption isotherm model correlates well with the uranium sorption equilibrium data for the concentration range of 20-200 mg/L. The maximum uranium sorption capacity onto magnetic Fe(3)O(4)@SiO(2) composite particles was estimated to be about 52 mg/g at 25 °C. The highest values of uranium desorption (98%) was achieved using 0.01 M HCl as the desorbing agent. Fe(3)O(4)@SiO(2) composite particles showed a good selectivity for uranium from aqueous solution with other interfering cation ions. Present study suggested that magnetic Fe(3)O(4)@SiO(2) composite particles can be used as a potential adsorbent for sorption uranium and also provided a simple, fast separation method for removal of heavy metal ion from aqueous solution. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Microscopic nucleon spectral function for finite nuclei featuring two- and three-nucleon short-range correlations: The model versus ab initio calculations for three-nucleon systems

    Science.gov (United States)

    Ciofi degli Atti, Claudio; Mezzetti, Chiara Benedetta; Morita, Hiko

    2017-04-01

    Background: Two-nucleon (2 N ) short-range correlations (SRC) in nuclei have been recently thoroughly investigated, both theoretically and experimentally and the study of three-nucleon (3 N ) SRC, which could provide important information on short-range hadronic structure, is underway. Novel theoretical ideas concerning 2 N and 3 N SRC are put forward in the present paper. Purpose: The general features of a microscopic one-nucleon spectral function which includes the effects of both 2 N and 3 N SRC and its comparison with ab initio spectral functions of the three-nucleon systems are illustrated. Methods: A microscopic and parameter-free one-nucleon spectral function expressed in terms of a convolution integral involving ab initio relative and center-of-mass (c.m.) momentum distributions of a 2 N pair and aimed at describing two- and three-nucleon short-range correlations, is obtained by using: (i) the two-nucleon momentum distributions obtained within ab initio approaches based upon nucleon-nucleon interactions of the Argonne family; (ii) the exact relation between one- and two-nucleon momentum distributions; (iii) the fundamental property of factorization of the nuclear wave function at short internucleon ranges. Results: The comparison between the ab initio spectral function of 3He and the one based upon the convolution integral shows that when the latter contains only two-nucleon short-range correlations the removal energy location of the peaks and the region around them exhibited by the ab initio spectral function are correctly predicted, unlike the case of the high and low removal energy tails; the inclusion of the effects of three-nucleon correlations brings the convolution model spectral function in much better agreement with the ab initio one; it is also found that whereas the three-nucleon short-range correlations dominate the high energy removal energy tail of the spectral function, their effects on the one-nucleon momentum distribution are almost one

  5. A rapid tattoo removal technique using a combination of pulsed Er:YAG and Q-Switched Nd:YAG in a split lesion protocol.

    Science.gov (United States)

    Sardana, Kabir; Ranjan, Rashmi; Kochhar, Atul M; Mahajan, Khushbu Goel; Garg, Vijay K

    2015-01-01

    Tattoo removal has evolved over the years and though Q-switched laser is the 'workhorse' laser, it invariably requires multiple sittings, which are dependent on numerous factors, including the skin colour, location of the tattoo, age of the tattoo, colour of pigment used, associated fibrosis and the kind of tattoo treated. Though ablative lasers, both pulsed CO2 and Er:YAG, have been used for recalcitrant tattoos, very few studies have been done comparing them with pigment-specific lasers. Our study was based on the premise that ablating the epidermis overlying the tattoo pigment with Er:YAG could help in gaining better access to the pigment which would enable the Q-switched laser to work effectively with less beam scattering. A study of rapid tattoo removal (RTR) technique using a combination of pulsed Er:YAG and Q-Switched Nd:YAG in a split lesion protocol. This prospective study was undertaken during 2010-13 at a laser Clinic in the Maulana Azad Medical College, New Delhi. A total of 10 patients were recruited, 5 of amateur tattoo and 5 of professional tattoo. After informed consent each tattoo was arbitrarily 'split' into two parts. One part was treated with QS Nd:YAG laser(1064 nm) and the other part with Er:YAG laser immediately followed by the QS Nd:YAG. The laser treatments were repeated at 6-week intervals until the tattoo pigment had cleared. On the combination side in subsequent sittings only the QS Nd:YAG was used, to minimize repetitive ablation. To ensure consistency in the intervention methods a trained dermatologist who was independent of the treatment delivery randomly rated 10% of the procedures. The mean improvement achieved by the Q-switched laser (2.93) was less than the combination laser (3.85) side (p = 0.001) and needed more sessions (3.8 vs. 1.6; p = 0.001). There was a statistically significant difference in the improvement on the combination side till the second session. On the combination side patients required a maximum of 2 sessions

  6. Spectral Variability of Two Rapidly Rotating Brown Dwarfs: 2MASS J08354256-0819237 and 2MASS J18212815+1414010

    OpenAIRE

    Schlawin, Everett; Burgasser, Adam J.; Karalidi, Theodora; Gizis, John; Teske, Johanna

    2017-01-01

    L dwarfs exhibit low-level, rotationally-modulated photometric variability generally associated with heterogeneous, cloud-covered atmospheres. The spectral character of these variations yields insight into the particle sizes and vertical structure of the clouds. Here we present the results of a high precision, ground-based, near-infrared, spectral monitoring study of two mid-type L dwarfs that have variability reported in the literature, 2MASS J08354256-0819237 and 2MASS J18212815+1414010, us...

  7. Review on CNC-Rapid Prototyping

    International Nuclear Information System (INIS)

    M Nafis O Z; Nafrizuan M Y; Munira M A; Kartina J

    2012-01-01

    This article reviewed developments of Computerized Numerical Control (CNC) technology in rapid prototyping process. Rapid prototyping (RP) can be classified into three major groups; subtractive, additive and virtual. CNC rapid prototyping is grouped under the subtractive category which involves material removal from the workpiece that is larger than the final part. Richard Wysk established the use of CNC machines for rapid prototyping using sets of 2½-D tool paths from various orientations about a rotary axis to machine parts without refixturing. Since then, there are few developments on this process mainly aimed to optimized the operation and increase the process capabilities to stand equal with common additive type of RP. These developments include the integration between machining and deposition process (hybrid RP), adoption of RP to the conventional machine and optimization of the CNC rapid prototyping process based on controlled parameters. The article ended by concluding that the CNC rapid prototyping research area has a vast space for improvement as in the conventional machining processes. Further developments and findings will enhance the usage of this method and minimize the limitation of current approach in building a prototype.

  8. High precision, rapid laser hole drilling

    Science.gov (United States)

    Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

    2013-04-02

    A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

  9. INTRINSIC ELECTROMAGNETIC VARIABILITY IN CELESTIAL OBJECTS CONTAINING RAPIDLY SPINNING BLACK HOLES

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fan, E-mail: fnzhang@bnu.edu.cn [Gravitational Wave and Cosmology Laboratory, Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Department of Physics and Astronomy, West Virginia University, P.O. Box 6315, Morgantown, WV 26506 (United States)

    2016-02-10

    Analytical studies have raised the concern that a mysterious expulsion of magnetic field lines by a rapidly spinning black hole (dubbed the black hole Meissner effect) would shut down the Blandford–Znajek process and quench the jets of active galactic nuclei and microquasars. This effect is, however, not seen observationally or in numerical simulations. Previous attempts at reconciling the predictions with observations have proposed several mechanisms to evade the Meissner effect. In this paper, we identify a new evasion mechanism and discuss its observational significance. Specifically, we show that the breakdown of stationarity is sufficient to remove the expulsion of the magnetic field at all multipole orders, and that the associated temporal variation is likely turbulent because of the existence of efficient mechanisms for sharing energy across different modes. Such an intrinsic (as opposed to being driven externally by, e.g., changes in the accretion rate) variability of the electromagnetic field can produce the recorded linear correlation between microvariability amplitudes and mean fluxes, help create magnetic randomness and seed sheared magnetic loops in jets, and lead to a better theoretical fit to the X-ray microvariability power spectral density.

  10. Combining Near-Infrared Spectroscopy and Chemometrics for Rapid Recognition of an Hg-Contaminated Plant

    Directory of Open Access Journals (Sweden)

    Bang-Cheng Tang

    2016-01-01

    Full Text Available The feasibility of rapid recognition of an Hg-contaminated plant as a soil pollution indicator was investigated using near-infrared spectroscopy (NIRS and chemometrics. The stem and leave of a native plant, Miscanthus floridulus (Labill. Warb. (MFLW, were collected from Hg-contaminated areas (n1=125 as well as from regular areas (n2=116. The samples were dried and crushed and the powders were sieved through an 80-mesh sieve. Reference analysis of Hg levels was performed using inductively coupled plasma-atomic emission spectrometry (ICP-AES. The actual Hg contents of contaminated and normal samples were 16.2–30.5 and 0.0–0.1 mg/Kg, respectively. The NIRS measurements of impacted sample powders were collected in the mode of reflectance. The DUPLEX algorithm was utilized to split the NIRS data into representative training and test sets. Different spectral preprocessing methods were performed to remove the unwanted and noncomposition-correlated spectral variations. Classification models were developed using partial least squares discrimination analysis (PLSDA based on the raw, smoothed, second-order derivative (D2, and standard normal variate (SNV data, respectively. The prediction accuracy obtained by PLSDA with each data preprocessing option was 100%, indicating pattern recognition of Hg-contaminated MFLW samples using NIRS data was in perfect consistence with the ICP-AES results. NIRS combined with chemometrics will provide a tool to screen the Hg-contaminated MFLW, which can be potentially used as an indicator of soil pollution.

  11. Removal of iron and manganese using biological roughing up flow filtration technology.

    Science.gov (United States)

    Pacini, Virginia Alejandra; María Ingallinella, Ana; Sanguinetti, Graciela

    2005-11-01

    The removal of iron and manganese from groundwater using biological treatment methods is almost unknown in Latin America. Biological systems used in Europe are based on the process of double rapid biofiltration during which dissolved oxygen and pH need to be strictly controlled in order to limit abiotic iron oxidation. The performance of roughing filter technology in a biological treatment process for the removal of iron and manganese, without the use of chemical agents and under natural pH conditions was studied. Two pilot plants, using two different natural groundwaters, were operated with the following treatment line: aeration, up flow roughing filtration and final filtration (either slow or rapid). Iron and manganese removal efficiencies were found to be between 85% and 95%. The high solid retention capability of the roughing filter means that it is possible to remove iron and manganese simultaneously by biotic and abiotic mechanisms. This system combines simple, low-cost operation and maintenance with high iron and manganese removal efficiencies, thus constituting a technology which is particularly suited to small waterworks.

  12. Research on marine and freshwater fish identification model based on hyper-spectral imaging technology

    Science.gov (United States)

    Fu, Yan; Guo, Pei-yuan; Xiang, Ling-zi; Bao, Man; Chen, Xing-hai

    2013-08-01

    With the gradually mature of hyper spectral image technology, the application of the meat nondestructive detection and recognition has become one of the current research focuses. This paper for the study of marine and freshwater fish by the pre-processing and feature extraction of the collected spectral curve data, combined with BP network structure and LVQ network structure, a predictive model of hyper spectral image data of marine and freshwater fish has been initially established and finally realized the qualitative analysis and identification of marine and freshwater fish quality. The results of this study show that hyper spectral imaging technology combined with the BP and LVQ Artificial Neural Network Model can be used for the identification of marine and freshwater fish detection. Hyper-spectral data acquisition can be carried out without any pretreatment of the samples, thus hyper-spectral imaging technique is the lossless, high- accuracy and rapid detection method for quality of fish. In this study, only 30 samples are used for the exploratory qualitative identification of research, although the ideal study results are achieved, we will further increase the sample capacity to take the analysis of quantitative identification and verify the feasibility of this theory.

  13. Rapid fish stock depletion in previously unexploited seamounts: the ...

    African Journals Online (AJOL)

    Rapid fish stock depletion in previously unexploited seamounts: the case of Beryx splendens from the Sierra Leone Rise (Gulf of Guinea) ... A spectral analysis and red-noise spectra procedure (REDFIT) algorithm was used to identify the red-noise spectrum from the gaps in the observed time-series of catch per unit effort by ...

  14. Constraining the location of rapid gamma-ray flares in the flat spectrum radio quasar 3C 273 [Constraining the location of rapid gamma-ray flares in the FSRQ 3C 273

    International Nuclear Information System (INIS)

    Rani, B.; Lott, B.; Krichbaum, T. P.; Fuhrmann, L.; Zensus, J. A.

    2013-01-01

    Here, we present a γ-ray photon flux and spectral variability study of the flat-spectrum radio quasar 3C 273 over a rapid flaring activity period between September 2009 to April 2010. Five major flares were observed in the source during this period. The most rapid flare observed in the source has a flux doubling time of 1.1 hr. The rapid γ-ray flares allow us to constrain the location and size of the γ-ray emission region in the source. The γγ-opacity constrains the Doppler factor δ_γ ≥ 10 for the highest energy (15 GeV) photon observed by the Fermi-Large Area Telescope (LAT). Causality arguments constrain the size of the emission region to 1.6 × 10"1"5 cm. The γ-ray spectra measured over this period show clear deviations from a simple power law with a break in the 1–2 GeV energy range. We discuss possible explanations for the origin of the γ-ray spectral breaks. Our study suggests that the γ-ray emission region in 3C 273 is located within the broad line region (< 1.6 pc). As a result, the spectral behavior and temporal characteristics of the individual flares indicate the presence of multiple shock scenarios at the base of the jet.

  15. Spectral CT metal artifact reduction with an optimization-based reconstruction algorithm

    Science.gov (United States)

    Gilat Schmidt, Taly; Barber, Rina F.; Sidky, Emil Y.

    2017-03-01

    Metal objects cause artifacts in computed tomography (CT) images. This work investigated the feasibility of a spectral CT method to reduce metal artifacts. Spectral CT acquisition combined with optimization-based reconstruction is proposed to reduce artifacts by modeling the physical effects that cause metal artifacts and by providing the flexibility to selectively remove corrupted spectral measurements in the spectral-sinogram space. The proposed Constrained `One-Step' Spectral CT Image Reconstruction (cOSSCIR) algorithm directly estimates the basis material maps while enforcing convex constraints. The incorporation of constraints on the reconstructed basis material maps is expected to mitigate undersampling effects that occur when corrupted data is excluded from reconstruction. The feasibility of the cOSSCIR algorithm to reduce metal artifacts was investigated through simulations of a pelvis phantom. The cOSSCIR algorithm was investigated with and without the use of a third basis material representing metal. The effects of excluding data corrupted by metal were also investigated. The results demonstrated that the proposed cOSSCIR algorithm reduced metal artifacts and improved CT number accuracy. For example, CT number error in a bright shading artifact region was reduced from 403 HU in the reference filtered backprojection reconstruction to 33 HU using the proposed algorithm in simulation. In the dark shading regions, the error was reduced from 1141 HU to 25 HU. Of the investigated approaches, decomposing the data into three basis material maps and excluding the corrupted data demonstrated the greatest reduction in metal artifacts.

  16. Spectral evolution of GRBs with negative spectral lag using Fermi GBM observations

    Science.gov (United States)

    Chakrabarti, Arundhati; Chaudhury, Kishor; Sarkar, Samir K.; Bhadra, Arunava

    2018-06-01

    The positive spectral lag of Gamma Ray Bursts (GRBs) is often explained in terms of hard-to-soft spectral evolution of GRB pulses. While positive lags of GRBs is very common, there are few GRB pulses that exhibits negative spectral lags. In the present work we examine whether negative lags of GRBs also can be interpreted in terms of spectral evolution of GRB pulses or not. Using Fermi-GBM data, we identify two GRBs, GRB 090426C and GRB 150213A, with clean pulses that exhibit negative spectral lag. An indication of soft to hard transition has been noticed for the negative spectral lag events from the spectral evolution study. The implication of the present findings on the models of GRB spectral lags are discussed.

  17. An experimental and analytical investigation into the effects of process vibrations on material removal rates during polishing

    Science.gov (United States)

    Mullany, B.; Mainuddin, M.; Williams, W.; Keanini, R.

    2013-06-01

    Experimental testing, using both commercially available polishing machines and a specially built test platform, demonstrates that material removal rates (MRRs) observed during polishing of fused silica are strongly affected by nanometer-scale vibration amplitudes. Specifically, a nanometer level increase in system vibrations can produce MRRs approximately 150% higher than on an inherently smoother running machine. Moreover the higher spatial frequency surface roughness values are little-effected by the spectral content of the polishing machine. Polishing under controlled conditions, using the test platform, shows that for vibration amplitudes, A ≲ 1.6 μm, and over a fairly wide range of vibration frequencies, MRR increases almost linearly with increasing input power. By contrast, for A ≳ 10 μm, MRR exhibits a rapid decay with increasing A. Order of magnitude analyses and physical arguments are presented in order to explain the qualitatively distinct MRR trends observed. In the small-amplitude limit, A ≲ 1.6 μm, two arguments are presented which suggest that the total observed removal rate, MRRtot, reflects the superposed action of chemical-mechanical removal, MRRcm, and vibration-driven, flow-induced removal, MRRflow, i.e., MRRtot=MRRcm+MRRflow. The analyses further indicate that MRRflow primarily reflects cyclic viscous shears and pressure gradients extant within the thin, non-Newtonian slurry film that exists between the polishing tool and workpiece. Shears and pressure gradients, and corresponding flow-induced MRRs, are, in turn, found to scale as √A /do ω, where A is the vibration amplitude, do is the characteristic gap thickness between the tool and workpiece, and ω is the vibration frequency. In the large-amplitude limit, A ≳ 5 μm, experimental measurements and a simple scaling argument show that the polishing slurry film becomes thick enough that the workpiece and polishing tool lose direct contact. In this limit, observed MRRs thus reflect

  18. A wavelet and least square filter based spatial-spectral denoising approach of hyperspectral imagery

    Science.gov (United States)

    Li, Ting; Chen, Xiao-Mei; Chen, Gang; Xue, Bo; Ni, Guo-Qiang

    2009-11-01

    Noise reduction is a crucial step in hyperspectral imagery pre-processing. Based on sensor characteristics, the noise of hyperspectral imagery represents in both spatial and spectral domain. However, most prevailing denosing techniques process the imagery in only one specific domain, which have not utilized multi-domain nature of hyperspectral imagery. In this paper, a new spatial-spectral noise reduction algorithm is proposed, which is based on wavelet analysis and least squares filtering techniques. First, in the spatial domain, a new stationary wavelet shrinking algorithm with improved threshold function is utilized to adjust the noise level band-by-band. This new algorithm uses BayesShrink for threshold estimation, and amends the traditional soft-threshold function by adding shape tuning parameters. Comparing with soft or hard threshold function, the improved one, which is first-order derivable and has a smooth transitional region between noise and signal, could save more details of image edge and weaken Pseudo-Gibbs. Then, in the spectral domain, cubic Savitzky-Golay filter based on least squares method is used to remove spectral noise and artificial noise that may have been introduced in during the spatial denoising. Appropriately selecting the filter window width according to prior knowledge, this algorithm has effective performance in smoothing the spectral curve. The performance of the new algorithm is experimented on a set of Hyperion imageries acquired in 2007. The result shows that the new spatial-spectral denoising algorithm provides more significant signal-to-noise-ratio improvement than traditional spatial or spectral method, while saves the local spectral absorption features better.

  19. From spectral holeburning memory to spatial-spectral microwave signal processing

    International Nuclear Information System (INIS)

    Babbitt, Wm Randall; Barber, Zeb W; Harrington, Calvin; Mohan, R Krishna; Sharpe, Tia; Bekker, Scott H; Chase, Michael D; Merkel, Kristian D; Stiffler, Colton R; Traxinger, Aaron S; Woidtke, Alex J

    2014-01-01

    Many storage and processing systems based on spectral holeburning have been proposed that access the broad bandwidth and high dynamic range of spatial-spectral materials, but only recently have practical systems been developed that exceed the performance and functional capabilities of electronic devices. This paper reviews the history of the proposed applications of spectral holeburning and spatial-spectral materials, from frequency domain optical memory to microwave photonic signal processing systems. The recent results of a 20 GHz bandwidth high performance spectrum monitoring system with the additional capability of broadband direction finding demonstrates the potential for spatial-spectral systems to be the practical choice for solving demanding signal processing problems in the near future. (paper)

  20. Changes in the Spectral Features of Zinc Phthalocyanine Induced by Nitrogen Dioxide Gas in Solution and in Solid Polymer Nanofiber Media.

    Science.gov (United States)

    Zugle, Ruphino; Tetteh, Samuel

    2017-03-01

    The changes in the spectral features of zinc phthalocyanine in the visible domain as a result of its interaction with nitrogen dioxide gas were assessed in this work. This was done both in solution and when the phthalocyanine was incorporated into a solid polystyrene polymer nanofiber matrix. The spectral changes were found to be spontaneous and marked in both cases suggesting a rapid response criterion for the detection of the gas. In particular, the functionalised nano-fabric material could serve as a practical fire alarm system as it rapidly detects the nitrogen dioxide gas generated during burning.

  1. Assessment of damage in composite laminates through dynamic, full-spectral interrogation of fiber Bragg grating sensors

    International Nuclear Information System (INIS)

    Propst, A; Peters, K; Zikry, M A; Schultz, S; Kunzler, W; Zhu, Z; Wirthlin, M; Selfridge, R

    2010-01-01

    In this study, we demonstrate the full-spectral interrogation of a fiber Bragg grating (FBG) sensor at 535 Hz. The sensor is embedded in a woven, graphite fiber–epoxy composite laminate subjected to multiple low-velocity impacts. The measurement of unique, time dependent spectral features from the FBG sensor permits classification of the laminate lifetime into five regimes. These damage regimes compare well with previous analysis of the same material system using combined global and local FBG sensor information. Observed transient spectral features include peak splitting, wide spectral broadening and a strong single peak at the end of the impact event. Such features could not be measured through peak wavelength interrogation of the FBG sensor. Cross-correlation of the measured spectra with the original embedded FBG spectrum permitted rapid visualization of average strains and the presence of transverse compressive strain on the optical fiber, but smeared out the details of the spectral profile

  2. Spectral Imaging by Upconversion

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2011-01-01

    We present a method to obtain spectrally resolved images using upconversion. By this method an image is spectrally shifted from one spectral region to another wavelength. Since the process is spectrally sensitive it allows for a tailored spectral response. We believe this will allow standard...... silicon based cameras designed for visible/near infrared radiation to be used for spectral images in the mid infrared. This can lead to much lower costs for such imaging devices, and a better performance....

  3. Primary bovine skeletal muscle cells enters apoptosis rapidly via the intrinsic pathway when available oxygen is removed.

    Directory of Open Access Journals (Sweden)

    Sissel Beate Rønning

    Full Text Available Muscle cells undergo changes post-mortem during the process of converting muscle into meat, and this complex process is far from revealed. Recent reports have suggested programmed cell death (apoptosis to be important in the very early period of converting muscle into meat. The dynamic balance that occurs between anti-apoptotic members, such as Bcl-2, and pro-apoptotic members (Bid, Bim helps determine whether the cell initiates apoptosis. In this study, we used primary bovine skeletal muscle cells, cultured in monolayers in vitro, to investigate if apoptosis is induced when oxygen is removed from the growth medium. Primary bovine muscle cells were differentiated to form myotubes, and anoxia was induced for 6h. The anoxic conditions significantly increased (P<0.05 the relative gene expression of anti- and pro-apoptotic markers (Aif, Bcl-2, Bid and Bim, and the PARK7 (P<0.05 and Grp75 (Hsp70 protein expressions were transiently increased. The anoxic conditions also led to a loss of mitochondrial membrane potential, which is an early apoptotic event, as well as cytochrome c release from the mitochondria. Finally, reorganization and degradation of cytoskeletal filaments occurred. These results suggest that muscle cells enters apoptosis via the intrinsic pathway rapidly when available oxygen in the muscle diminishes post-mortem.

  4. Universality of many-body two-nucleon momentum distributions: Correlated nucleon spectral function of complex nuclei

    Science.gov (United States)

    Ciofi degli Atti, Claudio; Morita, Hiko

    2017-12-01

    Background: The nuclear spectral function is a fundamental quantity that describes the mean-field and short-range correlation dynamics of nucleons embedded in the nuclear medium; its knowledge is a prerequisite for the interpretation of various electroweak scattering processes off nuclear targets aimed at providing fundamental information on strong and weak interactions. Whereas in the case of the three-nucleon and, partly, the four-nucleon systems, the spectral function can be calculated ab initio within a nonrelativistic many-body Schroedinger approach, in the case of complex nuclei only models of the correlated, high-momentum part of the spectral function are available so far. Purpose: The purpose of this paper is to present a new approach such that the spectral function for a specific nucleus can be obtained from a reliable many-body calculation based upon realistic nucleon-nucleon interactions, thus avoiding approximations leading to adjustable parameters. Methods: The expectation value of the nuclear many-body Hamiltonian, containing realistic nucleon-nucleon interaction of the Argonne family, is evaluated variationally by a normalization-conserving linked-cluster expansion and the resulting many-body correlated wave functions are used to calculate the one-nucleon and the two-nucleon momentum distributions; by analyzing the high-momentum behavior of the latter, the spectral function can be expressed in terms of a transparent convolution formula involving the relative and center-of-mass (c.m.) momentum distributions in specific regions of removal energy E and momentum k . Results: It is found that as a consequence of the factorization of the many-body wave functions at short internucleon separations, the high-momentum behavior of the two-nucleon momentum distributions in A =3 ,4 ,12 ,16 ,40 nuclei factorizes, at proper values of the relative and c.m. momenta, into the c.m. and relative momentum distributions, with the latter exhibiting a universal A

  5. Sex Differences in the Sleep EEG of Young Adults : Visual Scoring and Spectral Analysis

    NARCIS (Netherlands)

    Dijk, Derk Jan; Beersma, Domien G.M.; Bloem, Gerda M.

    1989-01-01

    Baseline sleep of 13 men (mean age of 23.5 years) and 15 women (21.9 years) was analyzed. Visual scoring of the electroencephalograms (EEGs) revealed no significant differences between the sexes in the amounts of slow-wave sleep and rapid-eye-movement (REM) sleep. Spectral analysis, however,

  6. RRTM: A rapid radiative transfer model

    Energy Technology Data Exchange (ETDEWEB)

    Mlawer, E.J.; Taubman, S.J.; Clough, S.A. [Atmospheric and Environmental Research, Inc., Cambridge, MA (United States)

    1996-04-01

    A rapid radiative transfer model (RRTM) for the calculation of longwave clear-sky fluxes and cooling rates has been developed. The model, which uses the correlated-k method, is both accurate and computationally fast. The foundation for RRTM is the line-by-line radiative transfer model (LBLRTM) from which the relevant k-distributions are obtained. LBLRTM, which has been extensively validated against spectral observations e.g., the high-resolution sounder and the Atmospheric Emitted Radiance Interferometer, is used to validate the flux and cooling rate results from RRTM. Validations of RRTM`s results have been performed for the tropical, midlatitude summer, and midlatitude winter atmospheres, as well as for the four Intercomparison of Radiation Codes in Climate Models (ICRCCM) cases from the Spectral Radiance Experiment (SPECTRE). Details of some of these validations are presented below. RRTM has the identical atmospheric input module as LBLRTM, facilitating intercomparisons with LBLRTM and application of the model at the Atmospheric Radiation Measurement Cloud and Radiation Testbed sites.

  7. The Spectral Properties of Gamma-ray Bursts: a Review of Recent Development

    Science.gov (United States)

    Teegarden, B. J.

    1983-01-01

    Developments in the spectroscopy of gamma ray bursts (GRB) are reviewed. The general question of the validity of the spectral results, particularly with regard to features in the spectrum, is discussed. Confirmations of these spectral features are summarized. Results from the KONUS experiments on Venera 13 and 14 are reviewed. The status of models of the continuum spectrum is summarized. A number of different radiation mechanisms appear capable of fitting the data. These include thermal bremsstrahlung, thermal synchrotron and inverse Compton. Rapid variability of the spectra shape on time scales 76] 0.25 sec. was reported. The characteristic energy of the spectrum was observed to vary over nearly an order of magnitude during individual events. A strong correlation between spectral hardness and luminosity was found. Low-energy (50 keV) absorption features and high-energy (400 keV) emission features continue to appear in GRB spectra. Understanding the origin of these lines in the context of the existing continuum models remains a difficult problem.

  8. A review of materials for spectral design coatings in signature management applications

    Science.gov (United States)

    Andersson, Kent E.; Škerlind, Christina

    2014-10-01

    The current focus in Swedish policy towards national security and high-end technical systems, together with a rapid development in multispectral sensor technology, adds to the utility of developing advanced materials for spectral design in signature management applications. A literature study was performed probing research databases for advancements. Qualitative text analysis was performed using a six-indicator instrument: spectrally selective reflectance; low gloss; low degree of polarization; low infrared emissivity; non-destructive properties in radar and in general controllability of optical properties. Trends are identified and the most interesting materials and coating designs are presented with relevant performance metrics. They are sorted into categories in the order of increasing complexity: pigments and paints, one-dimensional structures, multidimensional structures (including photonic crystals), and lastly biomimic and metamaterials. The military utility of the coatings is assessed qualitatively. The need for developing a framework for assessing the military utility of incrementally increasing the performance of spectrally selective coatings is identified.

  9. Phosphate removal from digested sludge supernatant using modified fly ash.

    Science.gov (United States)

    Xu, Ke; Deng, Tong; Liu, Juntan; Peng, Weigong

    2012-05-01

    The removal of phosphate in digested sludge supernatant by modified coal fly ash was investigated in this study. Modification of the fly ash by the addition of sulfuric acid could significantly enhance its immobilization ability. The experimental results also showed that adsorption of phosphate by the modified fly ash was rapid with the removal percentage of phosphate reaching an equilibrium of 98.62% in less than 5 minutes. The optimum pH for phosphate removal was 9 and the removal percentage increased with increasing adsorbent dosage. The effect of temperature on phosphate removal efficiency was not significant from 20 to 40 degrees C. X-ray diffraction and scanning electron microscope analyses showed that phosphate formed an amorphous precipitate with water-soluble calcium, aluminum, and iron ions in the modified fly ash.

  10. Examination of Spectral Transformations on Spectral Mixture Analysis

    Science.gov (United States)

    Deng, Y.; Wu, C.

    2018-04-01

    While many spectral transformation techniques have been applied on spectral mixture analysis (SMA), few study examined their necessity and applicability. This paper focused on exploring the difference between spectrally transformed schemes and untransformed scheme to find out which transformed scheme performed better in SMA. In particular, nine spectrally transformed schemes as well as untransformed scheme were examined in two study areas. Each transformed scheme was tested 100 times using different endmember classes' spectra under the endmember model of vegetation- high albedo impervious surface area-low albedo impervious surface area-soil (V-ISAh-ISAl-S). Performance of each scheme was assessed based on mean absolute error (MAE). Statistical analysis technique, Paired-Samples T test, was applied to test the significance of mean MAEs' difference between transformed and untransformed schemes. Results demonstrated that only NSMA could exceed the untransformed scheme in all study areas. Some transformed schemes showed unstable performance since they outperformed the untransformed scheme in one area but weakened the SMA result in another region.

  11. Removal of radionuclides at a waterworks

    International Nuclear Information System (INIS)

    Gaefvert, T.; Ellmark, C.; Holm, E.

    2002-01-01

    A waterworks, providing several large cities in the province of Scania with drinking-water, with an average production rate of 1.3 m 3. s -1 has been studied regarding its removal capacity for several natural and anthropogenic radionuclides. The raw water is surface water from lake Bolmen which is transported through an 80 km long tunnel in the bedrock before it enters the waterworks. The method used for purification is a combination of precipitation and filtration in sand filters. Two different purification lines are at the moment in use, one using A1 2 (SO 4 ) 3 as a coagulant and one using FeC1 3 . After coagulation and flocculation the precipitation is removed and the water is passed through two different sand filters (rapid-filtration and slow-filtration). Water samples have been collected at the lake, the inlet at the waterworks, after each of the flocculation basins (A1 2 (SO 4 ) 3 and FeC1 3 ), after rapid-filtration and from the municipal distribution net. The samples have been analysed with respect to its content of uranium, thorium, polonium, radium, plutonium and caesium. (au)

  12. Comparative study on aerosol removal by natural processes in containment in severe accident for AP1000 reactor

    International Nuclear Information System (INIS)

    Sun, Xiaohui; Cao, Xinrong; Shi, Xingwei; Yan, Jin

    2017-01-01

    Highlights: • Characteristics of aerosol distribution in containment are obtained. • Aerosol removal by natural processes is comparative studied by two methods. • Traditional rapid assessment method is conservative and can be applied in AP1000 reactor. - Abstract: Focusing on aerosol removal by naturally occurring processes in containment in severe accident for AP1000, integral severe accident code MELCOR and rapid assessment method mentioned in NUREG/CR-6189 are utilized to study aerosol removal by natural processes, respectively. Three typical severe accidents, induced by large break loss of coolant accident (LBLOCA), small break loss of coolant accident (SBLOCA) and steam generator tube rupture (SGTR), respectively, are selected for the study. The results obtained by two methods were further compared in the following several aspects: efficiency of aerosol removal by natural processes, peak time of aerosol suspended in containment atmosphere, peak amount of aerosol suspended in containment atmosphere, time when aerosol removal efficiency by natural processes is up to 99.9%. It was further concluded that results obtained by rapid assessment with shorter calculation process are more conservative. The analysis results provide reference to assessment method selection of severe accident source term for AP1000 nuclear emergency.

  13. a Spatio-Spectral Camera for High Resolution Hyperspectral Imaging

    Science.gov (United States)

    Livens, S.; Pauly, K.; Baeck, P.; Blommaert, J.; Nuyts, D.; Zender, J.; Delauré, B.

    2017-08-01

    Imaging with a conventional frame camera from a moving remotely piloted aircraft system (RPAS) is by design very inefficient. Less than 1 % of the flying time is used for collecting light. This unused potential can be utilized by an innovative imaging concept, the spatio-spectral camera. The core of the camera is a frame sensor with a large number of hyperspectral filters arranged on the sensor in stepwise lines. It combines the advantages of frame cameras with those of pushbroom cameras. By acquiring images in rapid succession, such a camera can collect detailed hyperspectral information, while retaining the high spatial resolution offered by the sensor. We have developed two versions of a spatio-spectral camera and used them in a variety of conditions. In this paper, we present a summary of three missions with the in-house developed COSI prototype camera (600-900 nm) in the domains of precision agriculture (fungus infection monitoring in experimental wheat plots), horticulture (crop status monitoring to evaluate irrigation management in strawberry fields) and geology (meteorite detection on a grassland field). Additionally, we describe the characteristics of the 2nd generation, commercially available ButterflEYE camera offering extended spectral range (475-925 nm), and we discuss future work.

  14. A SPATIO-SPECTRAL CAMERA FOR HIGH RESOLUTION HYPERSPECTRAL IMAGING

    Directory of Open Access Journals (Sweden)

    S. Livens

    2017-08-01

    Full Text Available Imaging with a conventional frame camera from a moving remotely piloted aircraft system (RPAS is by design very inefficient. Less than 1 % of the flying time is used for collecting light. This unused potential can be utilized by an innovative imaging concept, the spatio-spectral camera. The core of the camera is a frame sensor with a large number of hyperspectral filters arranged on the sensor in stepwise lines. It combines the advantages of frame cameras with those of pushbroom cameras. By acquiring images in rapid succession, such a camera can collect detailed hyperspectral information, while retaining the high spatial resolution offered by the sensor. We have developed two versions of a spatio-spectral camera and used them in a variety of conditions. In this paper, we present a summary of three missions with the in-house developed COSI prototype camera (600–900 nm in the domains of precision agriculture (fungus infection monitoring in experimental wheat plots, horticulture (crop status monitoring to evaluate irrigation management in strawberry fields and geology (meteorite detection on a grassland field. Additionally, we describe the characteristics of the 2nd generation, commercially available ButterflEYE camera offering extended spectral range (475–925 nm, and we discuss future work.

  15. Microbial degradation of pesticides in rapid sand filters used for drinking water treatment

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen

    significantly with the maximum methane concentration in the raw water and did not correlate with other water quality parameters, such as the ammonium concentration. Furthermore, the connection between bentazone degradation and methane oxidation in filter sand was demonstrated by inhibition experiments, in which...... sustainable methods to remove pesticides from polluted water sources. Aeration of anaerobic groundwater, followed by biological rapid sand filtration is a widespread technology in drinking water treatment. Even though these systems are not designed for removal of trace contaminants, they have shown potential...... for microbial degradation of pesticides and their degradation products. If pesticides can be removed in rapid sand filters, it is of large commercial interest due to the importance in maintaining a simple, sustainable water treatment. To take advantage of the microbial pesticide degradation and identify...

  16. Biochemical Removal of HAP Precursors From Coal

    Energy Technology Data Exchange (ETDEWEB)

    Olson, G.; Tucker, L.; Richards, J.

    1997-07-01

    This project addresses DOE`s interest in advanced concepts for controlling emissions of air toxics from coal-fired utility boilers. We are determining the feasibility of developing a biochemical process for the precombustion removal of substantial percentages of 13 inorganic hazardous air pollutant (HAP) precursors from coal. These HAP precursors are Sb, As, Be, Cd, Cr, Cl, Co, F, Pb, Hg, Mn, Ni, and Se. Although rapid physical coal cleaning is done routinely in preparation plants, biochemical processes for removal of HAP precursors from coal potentially offer advantages of deeper cleaning, more specificity, and less coal loss. Compared to chemical processes for coal cleaning, biochemical processes potentially offer lower costs and milder process conditions. Pyrite oxidizing bacteria, most notably Thiobacillusferrooxidans, are being evaluated in this project for their ability to remove HAP precursors from U.S. coals.

  17. Biochemical Removal of HAP Precursors From Coal

    International Nuclear Information System (INIS)

    Olson, G.; Tucker, L.; Richards, J.

    1997-07-01

    This project addresses DOE's interest in advanced concepts for controlling emissions of air toxics from coal-fired utility boilers. We are determining the feasibility of developing a biochemical process for the precombustion removal of substantial percentages of 13 inorganic hazardous air pollutant (HAP) precursors from coal. These HAP precursors are Sb, As, Be, Cd, Cr, Cl, Co, F, Pb, Hg, Mn, Ni, and Se. Although rapid physical coal cleaning is done routinely in preparation plants, biochemical processes for removal of HAP precursors from coal potentially offer advantages of deeper cleaning, more specificity, and less coal loss. Compared to chemical processes for coal cleaning, biochemical processes potentially offer lower costs and milder process conditions. Pyrite oxidizing bacteria, most notably Thiobacillusferrooxidans, are being evaluated in this project for their ability to remove HAP precursors from U.S. coals

  18. Near-infrared spectral imaging Michelson interferometer for astronomical applications

    Science.gov (United States)

    Wells, C. W.; Potter, A. E.; Morgan, T. H.

    1980-01-01

    The design and operation of an imaging Michelson interferometer-spectrometer used for near-infrared (0.8 micron to 2.5 microns) spectral imaging are reported. The system employs a rapid scan interferometer modified for stable low resolution (250/cm) performance and a 42 element PbS linear detector array. A microcomputer system is described which provides data acquisition, coadding, and Fourier transformation for near real-time presentation of the spectra of all 42 scene elements. The electronic and mechanical designs are discussed and telescope performance data presented.

  19. Differences in pyrimidine dimer removal between rat skin cells in vitro and in vivo

    International Nuclear Information System (INIS)

    Mullaart, E.; Lohman, P.H.; Vijg, J.

    1988-01-01

    Pyrimidine dimers, the most abundant type of DNA lesions induced by ultraviolet light (UV), are rapidly repaired in human skin fibroblasts in vitro. In the same cell type from rats, however, there is hardly any removal of such dimers. To investigate whether this low capacity of rat skin cells to repair lesions in their DNA is an inherent characteristic of this species or an artifact due to cell culturing, we measured the removal of UV-induced pyrimidine dimers from rat epidermal keratinocytes both in vitro and in vivo. Epidermal keratinocytes in vitro were unable to remove any dimers over the first 3 h after UV-irradiation, while only about 20% was removed during a repair period of 24 h. In this respect, these cells were not different from cultured rat fibroblasts. In contrast to the results obtained with keratinocytes in vitro, we observed a rapid repair of pyrimidine dimers in UV-irradiated keratinocytes in vivo over the first 3 h; this rapid repair phase was followed by a much slower repair phase between 3 and 24 h. These results are discussed in terms of the possibility that mammalian cells are able to switch from one DNA repair pathway to another

  20. Rapid Sequential in Situ Multiplexing with DNA Exchange Imaging in Neuronal Cells and Tissues.

    Science.gov (United States)

    Wang, Yu; Woehrstein, Johannes B; Donoghue, Noah; Dai, Mingjie; Avendaño, Maier S; Schackmann, Ron C J; Zoeller, Jason J; Wang, Shan Shan H; Tillberg, Paul W; Park, Demian; Lapan, Sylvain W; Boyden, Edward S; Brugge, Joan S; Kaeser, Pascal S; Church, George M; Agasti, Sarit S; Jungmann, Ralf; Yin, Peng

    2017-10-11

    To decipher the molecular mechanisms of biological function, it is critical to map the molecular composition of individual cells or even more importantly tissue samples in the context of their biological environment in situ. Immunofluorescence (IF) provides specific labeling for molecular profiling. However, conventional IF methods have finite multiplexing capabilities due to spectral overlap of the fluorophores. Various sequential imaging methods have been developed to circumvent this spectral limit but are not widely adopted due to the common limitation of requiring multirounds of slow (typically over 2 h at room temperature to overnight at 4 °C in practice) immunostaining. We present here a practical and robust method, which we call DNA Exchange Imaging (DEI), for rapid in situ spectrally unlimited multiplexing. This technique overcomes speed restrictions by allowing for single-round immunostaining with DNA-barcoded antibodies, followed by rapid (less than 10 min) buffer exchange of fluorophore-bearing DNA imager strands. The programmability of DEI allows us to apply it to diverse microscopy platforms (with Exchange Confocal, Exchange-SIM, Exchange-STED, and Exchange-PAINT demonstrated here) at multiple desired resolution scales (from ∼300 nm down to sub-20 nm). We optimized and validated the use of DEI in complex biological samples, including primary neuron cultures and tissue sections. These results collectively suggest DNA exchange as a versatile, practical platform for rapid, highly multiplexed in situ imaging, potentially enabling new applications ranging from basic science, to drug discovery, and to clinical pathology.

  1. A Fundamental Study on Spectrum Center Estimation of Solar Spectral Irradiation by the Statistical Pattern Recognition

    Science.gov (United States)

    Iijima, Aya; Suzuki, Kazumi; Wakao, Shinji; Kawasaki, Norihiro; Usami, Akira

    With a background of environmental problems and energy issues, it is expected that PV systems will be introduced rapidly and connected with power grids on a large scale in the future. For this reason, the concern to which PV power generation will affect supply and demand adjustment in electric power in the future arises and the technique of correctly grasping the PV power generation becomes increasingly important. The PV power generation depends on solar irradiance, temperature of a module and solar spectral irradiance. Solar spectral irradiance is distribution of the strength of the light for every wavelength. As the spectrum sensitivity of solar cell depends on kind of solar cell, it becomes important for exact grasp of PV power generation. Especially the preparation of solar spectral irradiance is, however, not easy because the observational instrument of solar spectral irradiance is expensive. With this background, in this paper, we propose a new method based on statistical pattern recognition for estimating the spectrum center which is representative index of solar spectral irradiance. Some numerical examples obtained by the proposed method are also presented.

  2. Spectral characteristics of natural and artificial earthquakes in the Lop Nor test site, China

    International Nuclear Information System (INIS)

    Korrat, I.M.; Gharib, A.A.; Abou Elenean, K.A.; Hussein, H.M.; ElGabry, M.N.

    2007-12-01

    A seismic discriminants based on the spectral seismogram and spectral magnitude techniques has been tested to discriminate between three events; a nuclear explosion which took place in Lop Nor, China with m b 6.1 and two earthquakes from the closest area with m b 5.5 and 5.3, respectively. The spectral seismogram of the three events shows that the frequency content of the nuclear explosion differs from that of the earthquakes where the P-wave is rich with high frequency content in the nuclear explosion than the corresponding earthquakes. It is also observed that the energy decays very rapidly for the nuclear explosion than that for the earthquakes. Furthermore, the spectral magnitudes reveal significant differences in the spectra between the nuclear explosion and the two earthquakes. These observed differences appear to be quite enough to provide a reliable discriminant. The estimated stress drop from the magnitude spectra indicates a higher stress drop of the nuclear explosion relative to the earthquakes of the same tectonic region. (author)

  3. Multi-layer imager design for mega-voltage spectral imaging

    Science.gov (United States)

    Myronakis, Marios; Hu, Yue-Houng; Fueglistaller, Rony; Wang, Adam; Baturin, Paul; Huber, Pascal; Morf, Daniel; Star-Lack, Josh; Berbeco, Ross

    2018-05-01

    The architecture of multi-layer imagers (MLIs) can be exploited to provide megavoltage spectral imaging (MVSPI) for specific imaging tasks. In the current work, we investigated bone suppression and gold fiducial contrast enhancement as two clinical tasks which could be improved with spectral imaging. A method based on analytical calculations that enables rapid investigation of MLI component materials and thicknesses was developed and validated against Monte Carlo computations. The figure of merit for task-specific imaging performance was the contrast-to-noise ratio (CNR) of the gold fiducial when the CNR of bone was equal to zero after a weighted subtraction of the signals obtained from each MLI layer. Results demonstrated a sharp increase in the CNR of gold when the build-up component or scintillation materials and thicknesses were modified. The potential for low-cost, prompt implementation of specific modifications (e.g. composition of the build-up component) could accelerate clinical translation of MVSPI.

  4. The removal kinetics of dissolved organic matter and the optical clarity of groundwater

    Science.gov (United States)

    Chapelle, Francis H.; Shen, Yuan; Strom, Eric W.; Benner, Ronald

    2016-09-01

    Concentrations of dissolved organic matter (DOM) and ultraviolet/visible light absorbance decrease systematically as groundwater moves through the unsaturated zones overlying aquifers and along flowpaths within aquifers. These changes occur over distances of tens of meters (m) implying rapid removal kinetics of the chromophoric DOM that imparts color to groundwater. A one-compartment input-output model was used to derive a differential equation describing the removal of DOM from the dissolved phase due to the combined effects of biodegradation and sorption. The general solution to the equation was parameterized using a 2-year record of dissolved organic carbon (DOC) concentration changes in groundwater at a long-term observation well. Estimated rates of DOC loss were rapid and ranged from 0.093 to 0.21 micromoles per liter per day (μM d-1), and rate constants for DOC removal ranged from 0.0021 to 0.011 per day (d-1). Applying these removal rate constants to an advective-dispersion model illustrates substantial depletion of DOC over flow-path distances of 200 m or less and in timeframes of 2 years or less. These results explain the low to moderate DOC concentrations (20-75 μM; 0.26-1 mg L-1) and ultraviolet absorption coefficient values ( a 254 < 5 m-1) observed in groundwater produced from 59 wells tapping eight different aquifer systems of the United States. The nearly uniform optical clarity of groundwater, therefore, results from similarly rapid DOM-removal kinetics exhibited by geologically and hydrologically dissimilar aquifers.

  5. Removal of irrelevant information from working memory: sometimes fast, sometimes slow, and sometimes not at all.

    Science.gov (United States)

    Oberauer, Klaus

    2018-03-12

    To function properly, working memory must be rapidly updated. Updating requires the removal of information no longer relevant. I present six experiments designed to explore the boundary conditions and the time course of removal. A condition in which three out of six memory items can be removed was compared to two baseline conditions in which either three or six items were encoded and maintained in working memory. The time for removal was varied. In experiment 1, in the removal condition, a distinct subset of three words was cued to be irrelevant after encoding all six words. With longer removal time, response times in the removal condition approximated those in the set-size 3 baseline, but accuracies stayed at the set-size 6 level. In experiment 2, in which a random subset of three words was cued as irrelevant, there was no evidence for removal. Experiments 3 and 4 showed that when each item is cued as relevant or irrelevant after its encoding, irrelevant items can be removed rapidly and completely. Experiments 5 and 6 showed that complete removal was no longer possible when words had to be processed before being cued as irrelevant. The pattern of findings can be explained by distinguishing two forms of removal: deactivation removes working-memory contents from the set of competitors for retrieval; unbinding contents from their contexts removes them from working memory entirely, so that they also cease to compete for limited capacity. © 2018 New York Academy of Sciences.

  6. A multi-process phytoremediation system for removal of polycyclic aromatic hydrocarbons from contaminated soils

    International Nuclear Information System (INIS)

    Huang Xiaodong; El-Alawi, Yousef; Penrose, Donna M.; Glick, Bernard R.; Greenberg, Bruce M.

    2004-01-01

    To improve phytoremediation processes, multiple techniques that comprise different aspects of contaminant removal from soils have been combined. Using creosote as a test contaminant, a multi-process phytoremediation system composed of physical (volatilization), photochemical (photooxidation) and microbial remediation, and phytoremediation (plant-assisted remediation) processes was developed. The techniques applied to realize these processes were land-farming (aeration and light exposure), introduction of contaminant degrading bacteria, plant growth promoting rhizobacteria (PGPR), and plant growth of contaminant-tolerant tall fescue (Festuca arundinacea). Over a 4-month period, the average efficiency of removal of 16 priority PAHs by the multi-process remediation system was twice that of land-farming, 50% more than bioremediation alone, and 45% more than phytoremediation by itself. Importantly, the multi-process system was capable of removing most of the highly hydrophobic, soil-bound PAHs from soil. The key elements for successful phytoremediation were the use of plant species that have the ability to proliferate in the presence of high levels of contaminants and strains of PGPR that increase plant tolerance to contaminants and accelerate plant growth in heavily contaminated soils. The synergistic use of these approaches resulted in rapid and massive biomass accumulation of plant tissue in contaminated soil, putatively providing more active metabolic processes, leading to more rapid and more complete removal of PAHs. - Persistent PAH contaminants in soils can be removed more completely and rapidly by using multiple remediation processes

  7. Removing forest canopy cover restores a reptile assemblage.

    Science.gov (United States)

    Pike, David A; Webb, Jonathan K; Shine, Richard

    2011-01-01

    Humans are rapidly altering natural systems, leading to changes in the distribution and abundance of species. However, so many changes are occurring simultaneously (e.g., climate change, habitat fragmentation) that it is difficult to determine the cause of population fluctuations from correlational studies. We used a manipulative field experiment to determine whether forest canopy cover directly influences reptile assemblages on rock outcrops in southeastern Australia. Our experimental design consisted of three types of rock outcrops: (1) shady sites in which overgrown vegetation was manually removed (n = 25); (2) overgrown controls (n = 30); and (3) sun-exposed controls (n = 20). Following canopy removal, we monitored reptile responses over 30 months. Canopy removal increased reptile species richness, the proportion of shelter sites used by reptiles, and relative abundances of five species that prefer sun-exposed habitats. Our manipulation also decreased the abundances of two shade-tolerant species. Canopy cover thus directly influences this reptile assemblage, with the effects of canopy removal being dependent on each species' habitat preferences (i.e., selection or avoidance of sun-exposed habitat). Our study suggests that increases in canopy cover can cause declines of open-habitat specialists, as previously suggested by correlative studies from a wide range of taxa. Given that reptile colonization of manipulated outcrops occurred rapidly, artificially opening the canopy in ecologically informed ways could help to conserve imperiled species with patchy distributions and low vagility that are threatened by vegetation overgrowth. One such species is Australia's most endangered snake, the broadheaded snake (Hoplocephalus bungaroides).

  8. Spatio-Temporal Saliency Perception via Hypercomplex Frequency Spectral Contrast

    Directory of Open Access Journals (Sweden)

    Zhiqiang Tian

    2013-03-01

    Full Text Available Salient object perception is the process of sensing the salient information from the spatio-temporal visual scenes, which is a rapid pre-attention mechanism for the target location in a visual smart sensor. In recent decades, many successful models of visual saliency perception have been proposed to simulate the pre-attention behavior. Since most of the methods usually need some ad hoc parameters or high-cost preprocessing, they are difficult to rapidly detect salient object or be implemented by computing parallelism in a smart sensor. In this paper, we propose a novel spatio-temporal saliency perception method based on spatio-temporal hypercomplex spectral contrast (HSC. Firstly, the proposed HSC algorithm represent the features in the HSV (hue, saturation and value color space and features of motion by a hypercomplex number. Secondly, the spatio-temporal salient objects are efficiently detected by hypercomplex Fourier spectral contrast in parallel. Finally, our saliency perception model also incorporates with the non-uniform sampling, which is a common phenomenon of human vision that directs visual attention to the logarithmic center of the image/video in natural scenes. The experimental results on the public saliency perception datasets demonstrate the effectiveness of the proposed approach compared to eleven state-of-the-art approaches. In addition, we extend the proposed model to moving object extraction in dynamic scenes, and the proposed algorithm is superior to the traditional algorithms.

  9. Multi-material decomposition of spectral CT images

    Science.gov (United States)

    Mendonça, Paulo R. S.; Bhotika, Rahul; Maddah, Mahnaz; Thomsen, Brian; Dutta, Sandeep; Licato, Paul E.; Joshi, Mukta C.

    2010-04-01

    Spectral Computed Tomography (Spectral CT), and in particular fast kVp switching dual-energy computed tomography, is an imaging modality that extends the capabilities of conventional computed tomography (CT). Spectral CT enables the estimation of the full linear attenuation curve of the imaged subject at each voxel in the CT volume, instead of a scalar image in Hounsfield units. Because the space of linear attenuation curves in the energy ranges of medical applications can be accurately described through a two-dimensional manifold, this decomposition procedure would be, in principle, limited to two materials. This paper describes an algorithm that overcomes this limitation, allowing for the estimation of N-tuples of material-decomposed images. The algorithm works by assuming that the mixing of substances and tissue types in the human body has the physicochemical properties of an ideal solution, which yields a model for the density of the imaged material mix. Under this model the mass attenuation curve of each voxel in the image can be estimated, immediately resulting in a material-decomposed image triplet. Decomposition into an arbitrary number of pre-selected materials can be achieved by automatically selecting adequate triplets from an application-specific material library. The decomposition is expressed in terms of the volume fractions of each constituent material in the mix; this provides for a straightforward, physically meaningful interpretation of the data. One important application of this technique is in the digital removal of contrast agent from a dual-energy exam, producing a virtual nonenhanced image, as well as in the quantification of the concentration of contrast observed in a targeted region, thus providing an accurate measure of tissue perfusion.

  10. La multiplication rapide du bananier et du plantain au Cameroun

    Directory of Open Access Journals (Sweden)

    Bonte, E.

    1995-01-01

    Full Text Available Rapid Multiplication of Banana and Plantain Trees in Cameroon. To increase the rate of multiplication of banana and plantain trees, several technics are practiced. Less sophisticated than tissue culture which necessitates a laboratory, this note presents two types of rapid multiplication practices : 1 ° by removal of the apical dominance, that is decapitation, bending over and false decapitation. 2° by spliting of corms and buds.

  11. Rapid thermal conditioning of sewage sludge

    Science.gov (United States)

    Zheng, Jianhong

    Rapid thermal conditioning (RTC) is a developing technology recently applied to sewage sludge treatment. Sludge is heated rapidly to a reaction temperature (up to about 220sp°C) under sufficient pressure to maintain the liquid phase. Reaction is quenched after 10 to 30 seconds when the mixture of sludge and steam pass through a pressure let-down valve. This process reduces the amount of sludge requiring land disposal, eliminates the need for polymer coagulant, improves dewaterability, increases methane production, and further reduces the concentration of pathogens. The odor problem associated with traditional thermal conditioning processes is largely minimized. Ammonia removal is readily integrated with the process. For this research, a pilot unit was constructed capable of processing 90 liters of sludge per hour. Over 22 runs were made with this unit using sludge from New York City Water Pollution Control Plants (WPCP). Sludges processed in this equipment were tested to determine the effect of RTC operating conditions on sludge dewaterability, biodegradability, and other factors affecting the incorporation of RTC into wastewater treatment plants. Dewaterability of thermally conditioned sludge was assessed for cetrifugeability and filterability. Bench scale centrifugation was used for evaluating centrifugeability, pressure filtration and capillary suction time (CST) for filterability. A mathematical model developed for centrifuge dewatering was used to predict the effect of RTC on full scale centrifuge performance. Particle size distribution and solids density of raw and treated PDS were also analyzed. An observed increase in sludge solids density at least partially explains its improved centrifugeability. An investigation of thermally conditioned amino acids showed that the L-isomer is highly biodegradable while the D-isomers are generally less so. Glucose is highly biodegradable, but rapidly becomes refractory as thermal conditioning time is lengthened. This

  12. Spectral image reconstruction using an edge preserving spatio-spectral Wiener estimation.

    Science.gov (United States)

    Urban, Philipp; Rosen, Mitchell R; Berns, Roy S

    2009-08-01

    Reconstruction of spectral images from camera responses is investigated using an edge preserving spatio-spectral Wiener estimation. A Wiener denoising filter and a spectral reconstruction Wiener filter are combined into a single spatio-spectral filter using local propagation of the noise covariance matrix. To preserve edges the local mean and covariance matrix of camera responses is estimated by bilateral weighting of neighboring pixels. We derive the edge-preserving spatio-spectral Wiener estimation by means of Bayesian inference and show that it fades into the standard Wiener reflectance estimation shifted by a constant reflectance in case of vanishing noise. Simulation experiments conducted on a six-channel camera system and on multispectral test images show the performance of the filter, especially for edge regions. A test implementation of the method is provided as a MATLAB script at the first author's website.

  13. Spectral Approach to Derive the Representation Formulae for Solutions of the Wave Equation

    Directory of Open Access Journals (Sweden)

    Gusein Sh. Guseinov

    2012-01-01

    Full Text Available Using spectral properties of the Laplace operator and some structural formula for rapidly decreasing functions of the Laplace operator, we offer a novel method to derive explicit formulae for solutions to the Cauchy problem for classical wave equation in arbitrary dimensions. Among them are the well-known d'Alembert, Poisson, and Kirchhoff representation formulae in low space dimensions.

  14. Global Learning Spectral Archive- A new Way to deal with Unknown Urban Spectra -

    Science.gov (United States)

    Jilge, M.; Heiden, U.; Habermeyer, M.; Jürgens, C.

    2015-12-01

    Rapid urbanization processes and the need of identifying urban materials demand urban planners and the remote sensing community since years. Urban planners cannot overcome the issue of up-to-date information of urban materials due to time-intensive fieldwork. Hyperspectral remote sensing can facilitate this issue by interpreting spectral signals to provide information of occurring materials. However, the complexity of urban areas and the occurrence of diverse urban materials vary due to regional and cultural aspects as well as the size of a city, which makes identification of surface materials a challenging analysis task. For the various surface material identification approaches, spectral libraries containing pure material spectra are commonly used, which are derived from field, laboratory or the hyperspectral image itself. One of the requirements for successful image analysis is that all spectrally different surface materials are represented by the library. Currently, a universal library, applicable in every urban area worldwide and taking each spectral variability into account, is and will not be existent. In this study, the issue of unknown surface material spectra and the demand of an urban site-specific spectral library is tackled by the development of a learning spectral archive tool. Starting with an incomplete library of labelled image spectra from several German cities, surface materials of pure image pixels will be identified in a hyperspectral image based on a similarity measure (e.g. SID-SAM). Additionally, unknown image spectra of urban objects are identified based on an object- and spectral-based-rule set. The detected unknown surface material spectra are entered with additional metadata, such as regional occurrence into the existing spectral library and thus, are reusable for further studies. Our approach is suitable for pure surface material detection of urban hyperspectral images that is globally applicable by taking incompleteness into account

  15. Predicting stem borer density in maize using RapidEye data and generalized linear models

    Science.gov (United States)

    Abdel-Rahman, Elfatih M.; Landmann, Tobias; Kyalo, Richard; Ong'amo, George; Mwalusepo, Sizah; Sulieman, Saad; Ru, Bruno Le

    2017-05-01

    Average maize yield in eastern Africa is 2.03 t ha-1 as compared to global average of 6.06 t ha-1 due to biotic and abiotic constraints. Amongst the biotic production constraints in Africa, stem borers are the most injurious. In eastern Africa, maize yield losses due to stem borers are currently estimated between 12% and 21% of the total production. The objective of the present study was to explore the possibility of RapidEye spectral data to assess stem borer larva densities in maize fields in two study sites in Kenya. RapidEye images were acquired for the Bomet (western Kenya) test site on the 9th of December 2014 and on 27th of January 2015, and for Machakos (eastern Kenya) a RapidEye image was acquired on the 3rd of January 2015. Five RapidEye spectral bands as well as 30 spectral vegetation indices (SVIs) were utilized to predict per field maize stem borer larva densities using generalized linear models (GLMs), assuming Poisson ('Po') and negative binomial ('NB') distributions. Root mean square error (RMSE) and ratio prediction to deviation (RPD) statistics were used to assess the models performance using a leave-one-out cross-validation approach. The Zero-inflated NB ('ZINB') models outperformed the 'NB' models and stem borer larva densities could only be predicted during the mid growing season in December and early January in both study sites, respectively (RMSE = 0.69-1.06 and RPD = 8.25-19.57). Overall, all models performed similar when all the 30 SVIs (non-nested) and only the significant (nested) SVIs were used. The models developed could improve decision making regarding controlling maize stem borers within integrated pest management (IPM) interventions.

  16. Fast and accurate spectral estimation for online detection of partial broken bar in induction motors

    Science.gov (United States)

    Samanta, Anik Kumar; Naha, Arunava; Routray, Aurobinda; Deb, Alok Kanti

    2018-01-01

    In this paper, an online and real-time system is presented for detecting partial broken rotor bar (BRB) of inverter-fed squirrel cage induction motors under light load condition. This system with minor modifications can detect any fault that affects the stator current. A fast and accurate spectral estimator based on the theory of Rayleigh quotient is proposed for detecting the spectral signature of BRB. The proposed spectral estimator can precisely determine the relative amplitude of fault sidebands and has low complexity compared to available high-resolution subspace-based spectral estimators. Detection of low-amplitude fault components has been improved by removing the high-amplitude fundamental frequency using an extended-Kalman based signal conditioner. Slip is estimated from the stator current spectrum for accurate localization of the fault component. Complexity and cost of sensors are minimal as only a single-phase stator current is required. The hardware implementation has been carried out on an Intel i7 based embedded target ported through the Simulink Real-Time. Evaluation of threshold and detectability of faults with different conditions of load and fault severity are carried out with empirical cumulative distribution function.

  17. Phosphorus removal from aquaculture wastewater and latex by ...

    African Journals Online (AJOL)

    Water pollution has always been a major problem in the environment. Polluted water is harmful for human health, thus, there is the need to clean water from polluting factors. One of the economical and rapid methods for removing elements is displacement of metals by biosorption. Three treatments in four replications for ...

  18. Individual differences in detecting rapidly presented fearful faces.

    Directory of Open Access Journals (Sweden)

    Dandan Zhang

    Full Text Available Rapid detection of evolutionarily relevant threats (e.g., fearful faces is important for human survival. The ability to rapidly detect fearful faces exhibits high variability across individuals. The present study aimed to investigate the relationship between behavioral detection ability and brain activity, using both event-related potential (ERP and event-related oscillation (ERO measurements. Faces with fearful or neutral facial expressions were presented for 17 ms or 200 ms in a backward masking paradigm. Forty-two participants were required to discriminate facial expressions of the masked faces. The behavioral sensitivity index d' showed that the detection ability to rapidly presented and masked fearful faces varied across participants. The ANOVA analyses showed that the facial expression, hemisphere, and presentation duration affected the grand-mean ERP (N1, P1, and N170 and ERO (below 20 Hz and lasted from 100 ms to 250 ms post-stimulus, mainly in theta band brain activity. More importantly, the overall detection ability of 42 subjects was significantly correlated with the emotion effect (i.e., fearful vs. neutral on ERP (r = 0.403 and ERO (r = 0.552 measurements. A higher d' value was corresponding to a larger size of the emotional effect (i.e., fearful--neutral of N170 amplitude and a larger size of the emotional effect of the specific ERO spectral power at the right hemisphere. The present results suggested a close link between behavioral detection ability and the N170 amplitude as well as the ERO spectral power below 20 Hz in individuals. The emotional effect size between fearful and neutral faces in brain activity may reflect the level of conscious awareness of fearful faces.

  19. Spectral domain optical coherence tomography imaging of subretinal bands associated with chronic retinal detachments

    OpenAIRE

    Kothari, Nikisha; Kuriyan, Ajay E; Flynn, Harry W

    2016-01-01

    Nikisha Kothari, Ajay E Kuriyan, Harry W Flynn JrDepartment of Ophthalmology, Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL, USAAbstract: We report three patients with subretinal bands associated with retinal detachment in chronic retinal detachments who underwent successful retinal reattachment. Subretinal bands before and after surgery can be identified on clinical examination and spectral domain optical coherence tomography. Removal of subr...

  20. Rapid 3D µ-printing of polymer optical whispering-gallery mode resonators.

    Science.gov (United States)

    Wu, Jushuai; Guo, Xin; Zhang, A Ping; Tam, Hwa-Yaw

    2015-11-16

    A novel microfabrication method for rapid printing of polymer optical whispering-gallery mode (WGM) resonators is presented. A 3D micro-printing technology based on high-speed optical spatial modulator (SLM) and high-power UV light source is developed to fabricate suspended-disk WGM resonator array using SU-8 photoresist. The optical spectral responses of the fabricated polymer WGM resonators were measured with a biconically tapered optical fiber. Experimental results reveal that the demonstrated method is very flexible and time-saving for rapid fabrication of complex polymer WGM resonators.

  1. Analysis of petroleum contaminated soils by spectral modeling and pure response profile recovery of n-hexane

    International Nuclear Information System (INIS)

    Chakraborty, Somsubhra; Weindorf, David C.; Li, Bin; Ali, Md. Nasim; Majumdar, K.; Ray, D.P.

    2014-01-01

    This pilot study compared penalized spline regression (PSR) and random forest (RF) regression using visible and near-infrared diffuse reflectance spectroscopy (VisNIR DRS) derived spectra of 164 petroleum contaminated soils after two different spectral pretreatments [first derivative (FD) and standard normal variate (SNV) followed by detrending] for rapid quantification of soil petroleum contamination. Additionally, a new analytical approach was proposed for the recovery of the pure spectral and concentration profiles of n-hexane present in the unresolved mixture of petroleum contaminated soils using multivariate curve resolution alternating least squares (MCR-ALS). The PSR model using FD spectra (r 2  = 0.87, RMSE = 0.580 log 10  mg kg −1 , and residual prediction deviation = 2.78) outperformed all other models tested. Quantitative results obtained by MCR-ALS for n-hexane in presence of interferences (r 2  = 0.65 and RMSE 0.261 log 10  mg kg −1 ) were comparable to those obtained using FD (PSR) model. Furthermore, MCR ALS was able to recover pure spectra of n-hexane. - Highlights: • We predicted soil petroleum contamination with VisNIR DRS spectra. • We examined 2 spectral pretreatments and 2 multivariate models. • MCR-ALS was used for compositional and spectral resolution of n-hexane. • Penalized spline regression performed best for quantifying soil TPH. • MCR-ALS was promising for resolution of complex soil–petroleum mixture. - Use of VisNIR DRS for rapid quantification of soil TPH and resolution of complex soil petroleum mixtures

  2. Automatic removal of eye-movement and blink artifacts from EEG signals.

    Science.gov (United States)

    Gao, Jun Feng; Yang, Yong; Lin, Pan; Wang, Pei; Zheng, Chong Xun

    2010-03-01

    Frequent occurrence of electrooculography (EOG) artifacts leads to serious problems in interpreting and analyzing the electroencephalogram (EEG). In this paper, a robust method is presented to automatically eliminate eye-movement and eye-blink artifacts from EEG signals. Independent Component Analysis (ICA) is used to decompose EEG signals into independent components. Moreover, the features of topographies and power spectral densities of those components are extracted to identify eye-movement artifact components, and a support vector machine (SVM) classifier is adopted because it has higher performance than several other classifiers. The classification results show that feature-extraction methods are unsuitable for identifying eye-blink artifact components, and then a novel peak detection algorithm of independent component (PDAIC) is proposed to identify eye-blink artifact components. Finally, the artifact removal method proposed here is evaluated by the comparisons of EEG data before and after artifact removal. The results indicate that the method proposed could remove EOG artifacts effectively from EEG signals with little distortion of the underlying brain signals.

  3. Accurate, fully-automated NMR spectral profiling for metabolomics.

    Directory of Open Access Journals (Sweden)

    Siamak Ravanbakhsh

    Full Text Available Many diseases cause significant changes to the concentrations of small molecules (a.k.a. metabolites that appear in a person's biofluids, which means such diseases can often be readily detected from a person's "metabolic profile"-i.e., the list of concentrations of those metabolites. This information can be extracted from a biofluids Nuclear Magnetic Resonance (NMR spectrum. However, due to its complexity, NMR spectral profiling has remained manual, resulting in slow, expensive and error-prone procedures that have hindered clinical and industrial adoption of metabolomics via NMR. This paper presents a system, BAYESIL, which can quickly, accurately, and autonomously produce a person's metabolic profile. Given a 1D 1H NMR spectrum of a complex biofluid (specifically serum or cerebrospinal fluid, BAYESIL can automatically determine the metabolic profile. This requires first performing several spectral processing steps, then matching the resulting spectrum against a reference compound library, which contains the "signatures" of each relevant metabolite. BAYESIL views spectral matching as an inference problem within a probabilistic graphical model that rapidly approximates the most probable metabolic profile. Our extensive studies on a diverse set of complex mixtures including real biological samples (serum and CSF, defined mixtures and realistic computer generated spectra; involving > 50 compounds, show that BAYESIL can autonomously find the concentration of NMR-detectable metabolites accurately (~ 90% correct identification and ~ 10% quantification error, in less than 5 minutes on a single CPU. These results demonstrate that BAYESIL is the first fully-automatic publicly-accessible system that provides quantitative NMR spectral profiling effectively-with an accuracy on these biofluids that meets or exceeds the performance of trained experts. We anticipate this tool will usher in high-throughput metabolomics and enable a wealth of new applications of

  4. Spectrally selective glazings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-08-01

    Spectrally selective glazing is window glass that permits some portions of the solar spectrum to enter a building while blocking others. This high-performance glazing admits as much daylight as possible while preventing transmission of as much solar heat as possible. By controlling solar heat gains in summer, preventing loss of interior heat in winter, and allowing occupants to reduce electric lighting use by making maximum use of daylight, spectrally selective glazing significantly reduces building energy consumption and peak demand. Because new spectrally selective glazings can have a virtually clear appearance, they admit more daylight and permit much brighter, more open views to the outside while still providing the solar control of the dark, reflective energy-efficient glass of the past. This Federal Technology Alert provides detailed information and procedures for Federal energy managers to consider spectrally selective glazings. The principle of spectrally selective glazings is explained. Benefits related to energy efficiency and other architectural criteria are delineated. Guidelines are provided for appropriate application of spectrally selective glazing, and step-by-step instructions are given for estimating energy savings. Case studies are also presented to illustrate actual costs and energy savings. Current manufacturers, technology users, and references for further reading are included for users who have questions not fully addressed here.

  5. Metal Removal and Antimicrobial Properties of Watermelon rind modified with clove

    OpenAIRE

    Othman N.; Azhar N.; Megat Abdul Rani P. S.; Mohamed Zaini H.

    2016-01-01

    The current rapid development of industrial activity indirectly discharged pollutant into the local water stream. One of the harmful industrial wastes that enter public drainage is heavy metal owing to its toxic, non-biodegradable and persistent in nature. Improper treatment of domestic waste also will discharged high amount of microbial. Various types of technology were developed for removing pollutant in wastewater, but most of the technology employed to address on removing organic content ...

  6. Adaptive Spectral Doppler Estimation

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jakobsson, Andreas; Jensen, Jørgen Arendt

    2009-01-01

    . The methods can also provide better quality of the estimated power spectral density (PSD) of the blood signal. Adaptive spectral estimation techniques are known to pro- vide good spectral resolution and contrast even when the ob- servation window is very short. The 2 adaptive techniques are tested......In this paper, 2 adaptive spectral estimation techniques are analyzed for spectral Doppler ultrasound. The purpose is to minimize the observation window needed to estimate the spectrogram to provide a better temporal resolution and gain more flexibility when designing the data acquisition sequence...... and compared with the averaged periodogram (Welch’s method). The blood power spectral capon (BPC) method is based on a standard minimum variance technique adapted to account for both averaging over slow-time and depth. The blood amplitude and phase estimation technique (BAPES) is based on finding a set...

  7. Analysis of pollution removal from wastewater by Ceratophyllum ...

    African Journals Online (AJOL)

    Water is one of the most stable and abundant complexes on nature that can be polluted with natural and human factors. Polluted water is harmful to human health and need to purify. One of the economic and rapid methods for elements removal is displacement of metals by biosorption. Two treatments in four replications for ...

  8. Removal of algal blooms from freshwater by the coagulation-magnetic separation method.

    Science.gov (United States)

    Liu, Dan; Wang, Peng; Wei, Guanran; Dong, Wenbo; Hui, Franck

    2013-01-01

    This research investigated the feasibility of changing waste into useful materials for water treatment and proposed a coagulation-magnetic separation technique. This technique was rapid and highly effective for clearing up harmful algal blooms in freshwater and mitigating lake eutrophication. A magnetic coagulant was synthesized by compounding acid-modified fly ash with magnetite (Fe(3)O(4)). Its removal effects on algal cells and dissolved organics in water were studied. After mixing, coagulation, and magnetic separation, the flocs obtained from the magnet surface were examined by SEM. Treated samples were withdrawn for the content determination of chlorophyll-a, turbidity, chemical oxygen demand (COD), total nitrogen, and total phosphorus. More than 99 % of algal cells were removed within 5 min after the addition of magnetic coagulant at optimal loadings (200 mg L(-1)). The removal efficiencies of COD, total nitrogen, and phosphorus were 93, 91, and 94 %, respectively. The mechanism of algal removal explored preliminarily showed that the magnetic coagulant played multiple roles in mesoporous adsorption, netting and bridging, as well as high magnetic responsiveness to a magnetic field. The magnetic-coagulation separation method can rapidly and effectively remove algae from water bodies and greatly mitigate eutrophication of freshwater using a new magnetic coagulant. The method has good performance, is low cost, can turn waste into something valuable, and provides reference and directions for future pilot and production scale-ups.

  9. Aqueous phosphate removal using nanoscale zero-valent iron

    International Nuclear Information System (INIS)

    Almeelbi, Talal; Bezbaruah, Achintya

    2012-01-01

    Nanoscale zero-valent iron (NZVI) particles have been used for the remediation of a wide variety of contaminants. NZVI particles have high reactivity because of high reactive surface area. In this study, NZVI slurry was successfully used for phosphate removal and recovery. Batch studies conducted using different concentrations of phosphate (1, 5, and 10 mg PO 4 3− -P/L with 400 mg NZVI/L) removed ∼96 to 100 % phosphate in 30 min. Efficacy of the NZVI in phosphate removal was found to 13.9 times higher than micro-ZVI (MZVI) particles with same NZVI and MZVI surface area concentrations used in batch reactors. Ionic strength, sulfate, nitrate, and humic substances present in the water affected in phosphate removal by NZVI but they may not have any practical significance in phosphate removal in the field. Phosphate recovery batch study indicated that better recovery is achieved at higher pH and it decreased with lowering of the pH of the aqueous solution. Maximum phosphate recovery of ∼78 % was achieved in 30 min at pH 12. The successful rapid removal of phosphate by NZVI from aqueous solution is expected to have great ramification for cleaning up nutrient rich waters.

  10. Hyperspectral image analysis for rapid and accurate discrimination of bacterial infections: A benchmark study.

    Science.gov (United States)

    Arrigoni, Simone; Turra, Giovanni; Signoroni, Alberto

    2017-09-01

    With the rapid diffusion of Full Laboratory Automation systems, Clinical Microbiology is currently experiencing a new digital revolution. The ability to capture and process large amounts of visual data from microbiological specimen processing enables the definition of completely new objectives. These include the direct identification of pathogens growing on culturing plates, with expected improvements in rapid definition of the right treatment for patients affected by bacterial infections. In this framework, the synergies between light spectroscopy and image analysis, offered by hyperspectral imaging, are of prominent interest. This leads us to assess the feasibility of a reliable and rapid discrimination of pathogens through the classification of their spectral signatures extracted from hyperspectral image acquisitions of bacteria colonies growing on blood agar plates. We designed and implemented the whole data acquisition and processing pipeline and performed a comprehensive comparison among 40 combinations of different data preprocessing and classification techniques. High discrimination performance has been achieved also thanks to improved colony segmentation and spectral signature extraction. Experimental results reveal the high accuracy and suitability of the proposed approach, driving the selection of most suitable and scalable classification pipelines and stimulating clinical validations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Rapid-scan EPR imaging.

    Science.gov (United States)

    Eaton, Sandra S; Shi, Yilin; Woodcock, Lukas; Buchanan, Laura A; McPeak, Joseph; Quine, Richard W; Rinard, George A; Epel, Boris; Halpern, Howard J; Eaton, Gareth R

    2017-07-01

    In rapid-scan EPR the magnetic field or frequency is repeatedly scanned through the spectrum at rates that are much faster than in conventional continuous wave EPR. The signal is directly-detected with a mixer at the source frequency. Rapid-scan EPR is particularly advantageous when the scan rate through resonance is fast relative to electron spin relaxation rates. In such scans, there may be oscillations on the trailing edge of the spectrum. These oscillations can be removed by mathematical deconvolution to recover the slow-scan absorption spectrum. In cases of inhomogeneous broadening, the oscillations may interfere destructively to the extent that they are not visible. The deconvolution can be used even when it is not required, so spectra can be obtained in which some portions of the spectrum are in the rapid-scan regime and some are not. The technology developed for rapid-scan EPR can be applied generally so long as spectra are obtained in the linear response region. The detection of the full spectrum in each scan, the ability to use higher microwave power without saturation, and the noise filtering inherent in coherent averaging results in substantial improvement in signal-to-noise relative to conventional continuous wave spectroscopy, which is particularly advantageous for low-frequency EPR imaging. This overview describes the principles of rapid-scan EPR and the hardware used to generate the spectra. Examples are provided of its application to imaging of nitroxide radicals, diradicals, and spin-trapped radicals at a Larmor frequency of ca. 250MHz. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Rapid Measurement of Soil Carbon in Rice Paddy Field of Lombok Island Indonesia Using Near Infrared Technology

    Science.gov (United States)

    Kusumo, B. H.; Sukartono, S.; Bustan, B.

    2018-02-01

    Measuring soil organic carbon (C) using conventional analysis is tedious procedure, time consuming and expensive. It is needed simple procedure which is cheap and saves time. Near infrared technology offers rapid procedure as it works based on the soil spectral reflectance and without any chemicals. The aim of this research is to test whether this technology able to rapidly measure soil organic C in rice paddy field. Soil samples were collected from rice paddy field of Lombok Island Indonesia, and the coordinates of the samples were recorded. Parts of the samples were analysed using conventional analysis (Walkley and Black) and some other parts were scanned using near infrared spectroscopy (NIRS) for soil spectral collection. Partial Least Square Regression (PLSR) Models were developed using data of soil C analysed using conventional analysis and data from soil spectral reflectance. The models were moderately successful to measure soil C in rice paddy field of Lombok Island. This shows that the NIR technology can be further used to monitor the C change in rice paddy soil.

  13. Test plan for preparing the Rapid Transuranic Monitoring Laboratory for field deployment

    International Nuclear Information System (INIS)

    McIsaac, C.V.; Sill, C.W.; Gehrke, R.J.; Killian, E.W.; Watts, K.D.

    1994-04-01

    This plan describes experimental work that will be performed during fiscal year 1994 to prepare the Rapid Transuranic Monitoring Laboratory (RTML) for routine field use by US Department of Energy (DOE) Environmental Restoration and Waste Management programs. The RTML is a mobile, field-deployable laboratory developed at the Idaho National Engineering Laboratory (INEL) that provides a rapid, cost-effective means of characterizing and monitoring radioactive waste remediation sites for low-level radioactive contaminants. Analytical instruments currently installed in the RTML include an extended-range, germanium photon analysis spectrometer with an automatic sample changer; two, large-area, ionization chamber alpha spectrometers; and four alpha continuous air monitors. The RTML was field tested at the INEL during June 1993 in conjunction with the Buried Waste Integrated Demonstration's remote retrieval demonstration. The major tasks described in this test plan are to (a) evaluate the beta detectors for use in screening soil samples for 90 Sr, (b) upgrade the alpha spectral analysis software programs, and (c) upgrade the photon spectral analysis software programs

  14. Spatial, Temporal and Spectral Satellite Image Fusion via Sparse Representation

    Science.gov (United States)

    Song, Huihui

    -MODIS image pairs, we build the corresponding relationship between the difference images of MODIS and ETM+ by training a low- and high-resolution dictionary pair from the given prior image pairs. In the second scenario, i.e., only one Landsat- MODIS image pair being available, we directly correlate MODIS and ETM+ data through an image degradation model. Then, the fusion stage is achieved by super-resolving the MODIS image combining the high-pass modulation in a two-layer fusion framework. Remarkably, the proposed spatial-temporal fusion methods form a unified framework for blending remote sensing images with phenology change or land-cover-type change. Based on the proposed spatial-temporal fusion models, we propose to monitor the land use/land cover changes in Shenzhen, China. As a fast-growing city, Shenzhen faces the problem of detecting the rapid changes for both rational city planning and sustainable development. However, the cloudy and rainy weather in region Shenzhen located makes the capturing circle of high-quality satellite images longer than their normal revisit periods. Spatial-temporal fusion methods are capable to tackle this problem by improving the spatial resolution of images with coarse spatial resolution but frequent temporal coverage, thereby making the detection of rapid changes possible. On two Landsat-MODIS datasets with annual and monthly changes, respectively, we apply the proposed spatial-temporal fusion methods to the task of multiple change detection. Afterward, we propose a novel spatial and spectral fusion method for satellite multispectral and hyperspectral (or high-spectral) images based on dictionary-pair learning and sparse non-negative matrix factorization. By combining the spectral information from hyperspectral image, which is characterized by low spatial resolution but high spectral resolution and abbreviated as LSHS, and the spatial information from multispectral image, which is featured by high spatial resolution but low spectral

  15. Spectral multitude and spectral dynamics reflect changing conjugation length in single molecules of oligophenylenevinylenes

    KAUST Repository

    Kobayashi, Hiroyuki; Tsuchiya, Kousuke; Ogino, Kenji; Vacha, Martin

    2012-01-01

    Single-molecule study of phenylenevinylene oligomers revealed distinct spectral forms due to different conjugation lengths which are determined by torsional defects. Large spectral jumps between different spectral forms were ascribed to torsional flips of a single phenylene ring. These spectral changes reflect the dynamic nature of electron delocalization in oligophenylenevinylenes and enable estimation of the phenylene torsional barriers. © 2012 The Owner Societies.

  16. Laboratory simulation of salt dissolution during waste removal

    International Nuclear Information System (INIS)

    Wiersma, B.J.; Parish, W.R.

    1997-01-01

    Laboratory experiments were performed to support the field demonstration of improved techniques for salt dissolution in waste tanks at the Savannah River Site. The tests were designed to investigate three density driven techniques for salt dissolution: (1) Drain-Add-Sit-Remove, (2) Modified Density Gradient, and (3) Continuous Salt Mining. Salt dissolution was observed to be a very rapid process as salt solutions with densities between 1.38-1.4 were frequently removed. Slower addition and removal rates and locating the outlet line at deeper levels below the top of the saltcake provided the best contact between the dissolution water and the saltcake. It was observed that dissolution with 1 M sodium hydroxide solution resulted in salt solutions that were within the current inhibitor requirements for the prevention of stress corrosion cracking. This result was independent of the density driven technique. However, if inhibited water (0.01 M sodium hydroxide and 0.011 M sodium nitrite) was utilized, the salt solutions were frequently outside the inhibitor requirements. Corrosion testing at conditions similar to the environments expected during waste removal was recommended

  17. [Review of digital ground object spectral library].

    Science.gov (United States)

    Zhou, Xiao-Hu; Zhou, Ding-Wu

    2009-06-01

    A higher spectral resolution is the main direction of developing remote sensing technology, and it is quite important to set up the digital ground object reflectance spectral database library, one of fundamental research fields in remote sensing application. Remote sensing application has been increasingly relying on ground object spectral characteristics, and quantitative analysis has been developed to a new stage. The present article summarized and systematically introduced the research status quo and development trend of digital ground object reflectance spectral libraries at home and in the world in recent years. Introducing the spectral libraries has been established, including desertification spectral database library, plants spectral database library, geological spectral database library, soil spectral database library, minerals spectral database library, cloud spectral database library, snow spectral database library, the atmosphere spectral database library, rocks spectral database library, water spectral database library, meteorites spectral database library, moon rock spectral database library, and man-made materials spectral database library, mixture spectral database library, volatile compounds spectral database library, and liquids spectral database library. In the process of establishing spectral database libraries, there have been some problems, such as the lack of uniform national spectral database standard and uniform standards for the ground object features as well as the comparability between different databases. In addition, data sharing mechanism can not be carried out, etc. This article also put forward some suggestions on those problems.

  18. Removal of foliar radiocaesium by sprinkling

    International Nuclear Information System (INIS)

    Anguissola Scotti, I.; Silva, S.; Carini, F.

    1993-01-01

    Tests of contamination of leaves with 134 Cs were carried out on wheat and tomato plants in order to discover whether sprinkler irrigation could remove some of the radioactivity deposited on the shoots. The results show that caesium is absorbed rapidly through the leaves of both wheat and tomato plants and that wheat grain and tomatoes in the sprinkled areas had 80% and 55% lower concentrations of 134 Cs, respectively, compared with those in the non-irrigated areas. (Author)

  19. Removal of heavy metals from aqueous solution by Carrot residues

    International Nuclear Information System (INIS)

    Eslamzadeh, T.; Nasernejad, B.; Bonakdar Pour, B.; Zamani, A.; Esmaail-Beygi, M.

    2004-01-01

    The removal of Copper(II), Zinc(II), and Chromium (III) from wastewater by carrot residues was investigated to evaluate cation exchange capacity. The effects of solution P H and co-ions were studied in batch experiments. Adsorption equilibria were initially rapidly established, and then decreased markedly after 10 min. Column experiments were carried out in a glass column filled with carrot residues to evaluate the metal removal capacity. The influences of the feed concentration and feed rate were also studied in order to compare the dynamic capacity for metal binding in different feed concentrations

  20. Simultaneous scoring of 10 chromosomes (9,13,14,15,16,18,21,22,X, and Y) in interphase nuclei by using spectral imaging

    Science.gov (United States)

    Fung, Jingly; Weier, Heinz-Ulli G.; Goldberg, James D.; Pedersen, Roger A.

    1999-06-01

    Numerical aberrations involving parts of or entire chromosomes have detrimental effects on mammalian embryonic, and perinatal development. Only few fetuses with chromosomal imbalances survive to term, and their abnormalities lead to stillbirth or cause severely altered phenotypes in the offspring (such as trisomies involving chromosomes 13, 18, 21, and anomalies of X, and Y). Because aneuploidy of any of the 24 chromosomes will have significant consequences, an optimized preimplantation and prenatal genetic diagnosis (PGD) test will score all the chromosomes. Since most cells to be analyzed will be in interphase rather than metaphase, we developed a rapid procedure for the analysis of interphase cells such as lymphocytes, amniocytes, or early embryonic cells (blastomeres). Our approach was based on in situ hybridization of chromosome-specific non-isotopically labeled DNA probes and Spectral Imaging. The Spectral Imaging system uses an interferometer instead of standard emission filters in a fluorescence microscope to record high resolution spectra from fluorescently stained specimens. This bio-imaging system combines the techniques of fluorescence optical microscopy, charged coupled device imaging, Fourier spectroscopy, light microscopy, and powerful analysis software. The probe set used here allowed simultaneous detection of 10 chromosomes (9, 13, 14, 15, 16, 18, 21, 22, X, Y) in interphase nuclei. Probes were obtained commercially or prepared in-house. Following 16 - 40 h hybridization to interphase cells and removal of unbound probes, image spectra (range 450 - 850 nm, resolution 10 nm) were recorded and analyzed using an SD200 Spectral Imaging system (ASI, Carlsbad, CA). Initially some amniocytes were unscoreable due to their thickness, and fixation protocols had to be modified to achieve satisfactory results. In summary, this study shows the simultaneous detection of at least 10 different chromosomes in interphase cells using a novel approach for multi

  1. [Applications of spectral analysis technique to monitoring grasshoppers].

    Science.gov (United States)

    Lu, Hui; Han, Jian-guo; Zhang, Lu-da

    2008-12-01

    Grasshopper monitoring is of great significance in protecting environment and reducing economic loss. However, how to predict grasshoppers accurately and effectively is a difficult problem for a long time. In the present paper, the importance of forecasting grasshoppers and its habitat is expounded, and the development in monitoring grasshopper populations and the common arithmetic of spectral analysis technique are illustrated. Meanwhile, the traditional methods are compared with the spectral technology. Remote sensing has been applied in monitoring the living, growing and breeding habitats of grasshopper population, and can be used to develop a forecast model combined with GIS. The NDVI values can be analyzed throughout the remote sensing data and be used in grasshopper forecasting. Hyper-spectra remote sensing technique which can be used to monitor grasshoppers more exactly has advantages in measuring the damage degree and classifying damage areas of grasshoppers, so it can be adopted to monitor the spatial distribution dynamic of rangeland grasshopper population. Differentialsmoothing can be used to reflect the relations between the characteristic parameters of hyper-spectra and leaf area index (LAI), and indicate the intensity of grasshopper damage. The technology of near infrared reflectance spectroscopy has been employed in judging grasshopper species, examining species occurrences and monitoring hatching places by measuring humidity and nutrient of soil, and can be used to investigate and observe grasshoppers in sample research. According to this paper, it is concluded that the spectral analysis technique could be used as a quick and exact tool in monitoring and forecasting the infestation of grasshoppers, and will become an important means in such kind of research for their advantages in determining spatial orientation, information extracting and processing. With the rapid development of spectral analysis methodology, the goal of sustainable monitoring

  2. Rapid and selective removal of preservative from ophthalmic formulations during eyedrops instillation.

    Science.gov (United States)

    Hsu, Kuan-Hui; Chauhan, Anuj

    2015-11-01

    About 70% of eyedrops contain benzalkonium chloride (BAK) as a preservative to prevent the growth of microorganisms. While preservatives are mandated to maintain sterility, many patients exhibit irritation and toxicity to such compounds. We propose to mitigate the ocular toxicity in the ocular formulations without compromising sterility by designing a device that can be incorporated into an eyedrops bottle to selectively remove the preservatives during the process of drop instillation. Here, we specifically focus on macroporous poly(2-hydroxyethyl methacrylate) (pHEMA) gel due to its excellent biocompatibility and high partition coefficient for BAK. In addition to specific selectivity for BAK, the device also requires high hydraulic permeability to allow drop dispensing without excessive pressure drop. The pHEMA monolith can remove nearly 100% of contained BAK from a 25 ml, 0.012% BAK solution with negligible uptake of the hydrophilic drugs such as timolol and dorzolamide. The filter, however, had to be pre-equilibrated with hydrophobic drugs to reach a high separation of BAK without reducing the concentration of the active drug. The average hydraulic permeability of the filter was 0.025 Darcy, which is about 5-fold lower than the ideal value. Incorporation of a pHEMA macroporous gel into an eyedrops bottle can virtually eliminate the exposure of the eyes to the preservatives without compromising the sterility. Our novel design can eliminate the preservative induced toxicity from eyedrops thereby impacting hundreds of millions of patients with chronic ophthalmic diseases such as glaucoma and dry eyes. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Design and implementation of a rapid-mixer flow cell for time-resolved infrared microspectroscopy

    International Nuclear Information System (INIS)

    Marinkovic, Nebojsa S.; Adzic, Aleksandar R.; Sullivan, Michael; Kovacs, Kevin; Miller, Lisa M.; Rousseau, Denis L.; Yeh, Syun-Ru; Chance, Mark R.

    2000-01-01

    A rapid mixer for the analysis of reactions in the millisecond and submillisecond time domains by Fourier-transform infrared microspectroscopy has been constructed. The cell was tested by examination of cytochrome-c folding kinetics. The device allows collection of full infrared spectral data on millisecond and faster time scales subsequent to chemical jump reaction initiation. The data quality is sufficiently good such that spectral fitting techniques could be applied to analysis of the data. Thus, this method provides an advantage over kinetic measurements at single wavelengths using infrared laser or diode sources, particularly where band overlap exists

  4. FERRATE TREATMENT FOR REMOVING CHROMIUM FROM HIGH-LEVEL RADIOACTIVE TANK WASTE

    International Nuclear Information System (INIS)

    Sylvester, Paul; Rutherford, Andy; Gonzalez-Martin, Anuncia; Kim, J.; Rapko, Brian M.; Lumetta, Gregg J.

    2000-01-01

    A method has been developed for removing chromium from alkaline high-level radioactive tank waste. Removing chromium from these wastes is critical in reducing the volume of waste requiring expensive immobilization and deep geologic disposition. The method developed is based on the oxidation of insoluble chromium(III) compounds to soluble chromate using ferrate. The tests conducted with a simulated Hanford tank sludge indicate that the chromium removal with ferrate is more efficient at 5 M NaOH than at 3 M NaOH. Chromium removal increases with increasing Fe(VI)/Cr(III) molar ratio, but the chromium removal tends to level out for Fe(VI)/Cr(III) greater than 10. Increasing temperature leads to better chromium removal, but higher temperatures also led to more rapid ferrate decomposition. Tests with radioactive Hanford tank waste generally confirmed the simulant results. In all cases examined, ferrate enhanced the chromium removal, with a typical removal of around 60-70% of the total chromium present in the washed sludge solids. The ferrate leachate solutions did not contain significant concentrations of transuranic elements, so these solutions could be handled as low-activity waste

  5. Acetaldehyde Removal from Indoor Air through Chemical Absorption Using L-Cysteine

    Directory of Open Access Journals (Sweden)

    Miyuki Noguchi

    2010-09-01

    Full Text Available The irreversible removal of acetaldehyde from indoor air via a chemical reaction with amino acids was investigated. To compare effectiveness, five types of amino acid (glycine, L-lysine, L-methionine, L-cysteine, and L-cystine were used as the reactants. First, acetaldehyde-laden air was introduced into aqueous solutions of each amino acid and the removal abilities were compared. Among the five amino acids, L-cysteine solution showed much higher removal efficiency, while the other amino acids solutions didn’t show any significant differences from the removal efficiency of water used as a control. Next, as a test of the removal abilities of acetaldehyde by semi-solid L-cysteine, a gel containing L-cysteine solution was put in a fluororesin bag filled with acetaldehyde gas, and the change of acetaldehyde concentration was measured. The L-cysteine-containing gel removed 80% of the acetaldehyde in the air within 24 hours. The removal ability likely depended on the unique reaction whereby acetaldehyde and L-cysteine rapidly produce 2-methylthiazolidine-4-carboxylic acid. These results suggested that the reaction between acetaldehyde and L-cysteine has possibilities for irreversibly removing toxic acetaldehyde from indoor air.

  6. Hyperspectral small animal fluorescence imaging: spectral selection imaging

    Science.gov (United States)

    Leavesley, Silas; Jiang, Yanan; Patsekin, Valery; Hall, Heidi; Vizard, Douglas; Robinson, J. Paul

    2008-02-01

    Molecular imaging is a rapidly growing area of research, fueled by needs in pharmaceutical drug-development for methods for high-throughput screening, pre-clinical and clinical screening for visualizing tumor growth and drug targeting, and a growing number of applications in the molecular biology fields. Small animal fluorescence imaging employs fluorescent probes to target molecular events in vivo, with a large number of molecular targeting probes readily available. The ease at which new targeting compounds can be developed, the short acquisition times, and the low cost (compared to microCT, MRI, or PET) makes fluorescence imaging attractive. However, small animal fluorescence imaging suffers from high optical scattering, absorption, and autofluorescence. Much of these problems can be overcome through multispectral imaging techniques, which collect images at different fluorescence emission wavelengths, followed by analysis, classification, and spectral deconvolution methods to isolate signals from fluorescence emission. We present an alternative to the current method, using hyperspectral excitation scanning (spectral selection imaging), a technique that allows excitation at any wavelength in the visible and near-infrared wavelength range. In many cases, excitation imaging may be more effective at identifying specific fluorescence signals because of the higher complexity of the fluorophore excitation spectrum. Because the excitation is filtered and not the emission, the resolution limit and image shift imposed by acousto-optic tunable filters have no effect on imager performance. We will discuss design of the imager, optimizing the imager for use in small animal fluorescence imaging, and application of spectral analysis and classification methods for identifying specific fluorescence signals.

  7. SpectralNET – an application for spectral graph analysis and visualization

    Directory of Open Access Journals (Sweden)

    Schreiber Stuart L

    2005-10-01

    Full Text Available Abstract Background Graph theory provides a computational framework for modeling a variety of datasets including those emerging from genomics, proteomics, and chemical genetics. Networks of genes, proteins, small molecules, or other objects of study can be represented as graphs of nodes (vertices and interactions (edges that can carry different weights. SpectralNET is a flexible application for analyzing and visualizing these biological and chemical networks. Results Available both as a standalone .NET executable and as an ASP.NET web application, SpectralNET was designed specifically with the analysis of graph-theoretic metrics in mind, a computational task not easily accessible using currently available applications. Users can choose either to upload a network for analysis using a variety of input formats, or to have SpectralNET generate an idealized random network for comparison to a real-world dataset. Whichever graph-generation method is used, SpectralNET displays detailed information about each connected component of the graph, including graphs of degree distribution, clustering coefficient by degree, and average distance by degree. In addition, extensive information about the selected vertex is shown, including degree, clustering coefficient, various distance metrics, and the corresponding components of the adjacency, Laplacian, and normalized Laplacian eigenvectors. SpectralNET also displays several graph visualizations, including a linear dimensionality reduction for uploaded datasets (Principal Components Analysis and a non-linear dimensionality reduction that provides an elegant view of global graph structure (Laplacian eigenvectors. Conclusion SpectralNET provides an easily accessible means of analyzing graph-theoretic metrics for data modeling and dimensionality reduction. SpectralNET is publicly available as both a .NET application and an ASP.NET web application from http://chembank.broad.harvard.edu/resources/. Source code is

  8. (LMRG): Microscope Resolution, Objective Quality, Spectral Accuracy and Spectral Un-mixing

    Science.gov (United States)

    Bayles, Carol J.; Cole, Richard W.; Eason, Brady; Girard, Anne-Marie; Jinadasa, Tushare; Martin, Karen; McNamara, George; Opansky, Cynthia; Schulz, Katherine; Thibault, Marc; Brown, Claire M.

    2012-01-01

    The second study by the LMRG focuses on measuring confocal laser scanning microscope (CLSM) resolution, objective lens quality, spectral imaging accuracy and spectral un-mixing. Affordable test samples for each aspect of the study were designed, prepared and sent to 116 labs from 23 countries across the globe. Detailed protocols were designed for the three tests and customized for most of the major confocal instruments being used by the study participants. One protocol developed for measuring resolution and objective quality was recently published in Nature Protocols (Cole, R. W., T. Jinadasa, et al. (2011). Nature Protocols 6(12): 1929–1941). The first study involved 3D imaging of sub-resolution fluorescent microspheres to determine the microscope point spread function. Results of the resolution studies as well as point spread function quality (i.e. objective lens quality) from 140 different objective lenses will be presented. The second study of spectral accuracy looked at the reflection of the laser excitation lines into the spectral detection in order to determine the accuracy of these systems to report back the accurate laser emission wavelengths. Results will be presented from 42 different spectral confocal systems. Finally, samples with double orange beads (orange core and orange coating) were imaged spectrally and the imaging software was used to un-mix fluorescence signals from the two orange dyes. Results from 26 different confocal systems will be summarized. Time will be left to discuss possibilities for the next LMRG study.

  9. Retrieval of spheroid particle size distribution from spectral extinction data in the independent mode using PCA approach

    International Nuclear Information System (INIS)

    Tang, Hong; Lin, Jian-Zhong

    2013-01-01

    An improved anomalous diffraction approximation (ADA) method is presented for calculating the extinction efficiency of spheroids firstly. In this approach, the extinction efficiency of spheroid particles can be calculated with good accuracy and high efficiency in a wider size range by combining the Latimer method and the ADA theory, and this method can present a more general expression for calculating the extinction efficiency of spheroid particles with various complex refractive indices and aspect ratios. Meanwhile, the visible spectral extinction with varied spheroid particle size distributions and complex refractive indices is surveyed. Furthermore, a selection principle about the spectral extinction data is developed based on PCA (principle component analysis) of first derivative spectral extinction. By calculating the contribution rate of first derivative spectral extinction, the spectral extinction with more significant features can be selected as the input data, and those with less features is removed from the inversion data. In addition, we propose an improved Tikhonov iteration method to retrieve the spheroid particle size distributions in the independent mode. Simulation experiments indicate that the spheroid particle size distributions obtained with the proposed method coincide fairly well with the given distributions, and this inversion method provides a simple, reliable and efficient method to retrieve the spheroid particle size distributions from the spectral extinction data. -- Highlights: ► Improved ADA is presented for calculating the extinction efficiency of spheroids. ► Selection principle about spectral extinction data is developed based on PCA. ► Improved Tikhonov iteration method is proposed to retrieve the spheroid PSD.

  10. Characterizing CDOM Spectral Variability Across Diverse Regions and Spectral Ranges

    Science.gov (United States)

    Grunert, Brice K.; Mouw, Colleen B.; Ciochetto, Audrey B.

    2018-01-01

    Satellite remote sensing of colored dissolved organic matter (CDOM) has focused on CDOM absorption (aCDOM) at a reference wavelength, as its magnitude provides insight into the underwater light field and large-scale biogeochemical processes. CDOM spectral slope, SCDOM, has been treated as a constant or semiconstant parameter in satellite retrievals of aCDOM despite significant regional and temporal variabilities. SCDOM and other optical metrics provide insights into CDOM composition, processing, food web dynamics, and carbon cycling. To date, much of this work relies on fluorescence techniques or aCDOM in spectral ranges unavailable to current and planned satellite sensors (e.g., global variability in SCDOM and fit deviations in the aCDOM spectra using the recently proposed Gaussian decomposition method. From this, we investigate if global variability in retrieved SCDOM and Gaussian components is significant and regionally distinct. We iteratively decreased the spectral range considered and analyzed the number, location, and magnitude of fitted Gaussian components to understand if a reduced spectral range impacts information obtained within a common spectral window. We compared the fitted slope from the Gaussian decomposition method to absorption-based indices that indicate CDOM composition to determine the ability of satellite-derived slope to inform the analysis and modeling of large-scale biogeochemical processes. Finally, we present implications of the observed variability for remote sensing of CDOM characteristics via SCDOM.

  11. Curatr: a web application for creating, curating and sharing a mass spectral library.

    Science.gov (United States)

    Palmer, Andrew; Phapale, Prasad; Fay, Dominik; Alexandrov, Theodore

    2018-04-15

    We have developed a web application curatr for the rapid generation of high quality mass spectral fragmentation libraries from liquid-chromatography mass spectrometry datasets. Curatr handles datasets from single or multiplexed standards and extracts chromatographic profiles and potential fragmentation spectra for multiple adducts. An intuitive interface helps users to select high quality spectra that are stored along with searchable molecular information, the providence of each standard and experimental metadata. Curatr supports exports to several standard formats for use with third party software or submission to repositories. We demonstrate the use of curatr to generate the EMBL Metabolomics Core Facility spectral library http://curatr.mcf.embl.de. Source code and example data are at http://github.com/alexandrovteam/curatr/. palmer@embl.de. Supplementary data are available at Bioinformatics online.

  12. Self-assembly modified-mushroom nanocomposite for rapid removal of hexavalent chromium from aqueous solution with bubbling fluidized bed.

    Science.gov (United States)

    Xu, Fei; Liu, Xu; Chen, Yijiao; Zhang, Ke; Xu, Heng

    2016-05-18

    A self-assembled modified Pleurotus Cornucopiae material (SMPM) combined with improved Intermittent Bubbling Fluidized Bed (IBFB) was investigated to remove the hexavalent chromium ions in aqueous solution. After the modification, the powder-like raw material gradually self-assembled together to SMPM, which had crinkly porous structure, improved the Cr-accommodation ability in a sound manner. Optimized by Taguchi method, Cr(VI) removal efficiency was up to 75.91% and 48.01% for 100 mg/L and 500 mg/L initial concentration of Cr(VI), respectively. Results indicated that the metal removal was dependent on dosage of adsorbent, particle diameter and treatment time. The experimental data obtained from the biosorption process was successfully correlated with Freundlich isotherm model. Thermodynamic study indicated the endothermic nature of the process. The results confirmed that self-assembly modified Pleurotus Cornucopiae material could be applied for the removal of heavy metal from wastewater in continuous fluidized bed process.

  13. Salicylate removal by charcoal heamoperfusion in experimental intoxication in dogs

    International Nuclear Information System (INIS)

    Brookings, C.H.; Ramsey, J.D.

    1975-01-01

    The removal of salicylate by extracorporeal circulation of blood through a column of encapsulated charcoal (haemoperfusion) has been studied experimentally in intoxicated dogs (greyhounds). The average time taken to reduce the whole blood salicylate level to one-half of the initial equilibrium level in 30 kg dogs was 2 hrs. A half-life of 3 hrs is predicted for salicylate removal by haemoperfusion in a 70 kg man and this rate of removal is shown to be comparable to that reported for haemodialysis. No unacceptable adverse physiological, biochemical, or haematological effects were found to result from haemoperfusion. The possible use of this technique in the management of severe salicylate poisoning in man is discussed. Haemoperfusion is foreseen as providing a method of rapid removal of salicylate in circumstances where forced diuresis is contra-indicated or inadequate and haemodialysis is not readily available. (orig.) [de

  14. Processes of microbial pesticide degradation in rapid sand filters for treatment of drinking water

    DEFF Research Database (Denmark)

    Hedegaard, Mathilde Jørgensen; Albrechtsen, Hans-Jørgen

    Aerobic rapid sand filters for treatment of groundwater at waterworks were investigated for the ability to remove pesticides. The potential, kinetics and mechanisms of microbial pesticide removal was investigated in microcosms consisting of filter sand, treated water and pesticides in initial...... concentrations of 0.04-2.4 μg/L. The pesticides were removed from the water in microcosms with filter sand from all three investigated sand filters. Within the experimental periode of six to 13 days, 65-85% of the bentazone, 86-93% of the glyphosate, 97-99% of the p-nitrophenol was removed from the water phase...

  15. Elementary principles of spectral distributions

    International Nuclear Information System (INIS)

    French, J.B.

    1980-01-01

    It is a common observation that as we add particles, one by one, to a simple system, things get steadily more and more complicated. For example if the system is describable in shell-model terms, i.e., with a model space in which m particles are distributed over N single-particle states, then as long as m << N, the dimensionality increases rapidly with particle number. On the other hand, for the usual (1 + 2)-body Hamiltonian, the (m greater than or equal to 2)-particle spectrum and wave functions are determined by operators defined in the one-particle space (for the single-particle energies) and the two-particle space (for the interactions). We may say then that the input information becomes more and more fragmented as the particle number increases, the fixed amount of information being distributed over more and more matrix elements. On the other hand there arise also new simplicities whose origin is connected with the operation of statistical laws. There is a macroscopic simplicity corresponding to the fact that the smoothed spectrum takes on a characteristic shape defined by a few parameters (low-order moments) of the spectrum. There is a microscopic simplicity corresponding to a remarkable spectral rigidity which extends over the entire spectrum and guarantees us that the fluctuations from uniformity in the spectrum are small and in many cases carry little information. The purpose of spectral-distribution theory, as applied to these problems, is to deal with the complexities by taking advantage of the simplicities

  16. Quasi-elastic spectral change of stored UCN

    International Nuclear Information System (INIS)

    Geltenbort, P.; Butterworth, J.; Steyerl, A.; Kwon, O.; Yerozolimsky, B.; Achiwa, N.

    2001-01-01

    UCN within a narrow spectral range were stored in a Fomblin grease coated trap. After filling the trap the bandwidth of storable UCN could be reduced to zero by an absorber. This procedure did, however, not remove all UCN. As in our previous measurements, the remaining UCN were found to leave the trap with an efflux time constant significantly larger than the value measured for the initial UCN spectrum. The remaining fraction of UCN was reduced to zero only when the absorber was brought down almost to the bottom of the trap. The data can be explained, qualitatively, by quasi-elastic UCN down-scattering by about 4 neV during the filling process. The deduced probability for this process is compared to a calculation for a model of hydrogen diffusing within a thin hydrogenous layer on top of the Fomblin grease. (author)

  17. Multiple-electron removal and molecular fragmentation of CO by fast F4+ impact

    International Nuclear Information System (INIS)

    Ben-Itzhak, I.; Ginther, S.G.; Carnes, K.D.

    1993-01-01

    Multiple-electron removal from and molecular fragmentation of carbon monoxide molecules caused by collisions with 1-MeV/amu F 4+ ions were studied using the coincidence time-of-flight technique. In these collisions, multiple-electron removal of the target molecule is a dominant process. Cross sections for the different levels of ionization of the CO molecule during the collision were determined. The relative cross sections of ionization decrease with increasing number of electrons removed in a similar way as seen in atomic targets. This behavior is in agreement with a two-step mechanism, where first the molecule is ionized by a Franck-Condon ionization and then the molecular ion dissociates. Most of the highly charged intermediate states of the molecule dissociate rapidly. Only CO + and CO 2+ molecular ions have been seen to survive long enough to be detected as molecular ions. The relative cross sections for the different breakup channels were evaluated for collisions in which the molecule broke into two charged fragments as well as for collisions where only a single charged molecular ion or fragment were produced. The average charge state of each fragment resulting from CO Q+ →C i+ +O j+ breakup increases with the number of electrons removed from the molecule approximately following the relationship bar i=bar j=Q/2 as long as K-shell electrons are not removed. This does not mean that the charge-state distribution is exactly symmetric, as, in general, removing electrons from the carbon fragment is slightly more likely than removing electrons from the oxygen due to the difference in binding energy. The cross sections for molecular breakup into a charged fragment and a neutral fragment drop rapidly with an increasing number of electrons removed

  18. Ferrate treatment for removing chromium from high-level radioactive tank waste.

    Science.gov (United States)

    Sylvester, P; Rutherford, L A; Gonzalez-Martin, A; Kim, J; Rapko, B M; Lumetta, G J

    2001-01-01

    A method has been developed for removing chromium from alkaline high-level radioactive tank waste. Removing chromium from these wastes is critical in reducing the volume of waste requiring expensive immobilization and deep geologic disposition. The method developed is based on the oxidation of insoluble chromium(III) compounds to soluble chromate using ferrate. This method could be generally applicable to removing chromium from chromium-contaminated solids, when coupled with a subsequent reduction of the separated chromate back to chromium(III). The tests conducted with a simulated Hanford tank sludge indicate that the chromium removal with ferrate is more efficient at 5 M NaOH than at 3 M NaOH. Chromium removal increases with increasing Fe(VI)/Cr(II) molar ratio, but the chromium removal tends to level out for Fe(VI)/ Cr(III) greaterthan 10. Increasingtemperature leadsto better chromium removal, but higher temperatures also led to more rapid ferrate decomposition. Tests with radioactive Hanford tank waste generally confirmed the simulant results. In all cases examined, ferrate enhanced the chromium removal, with a typical removal of around 60-70% of the total chromium present in the washed sludge solids. The ferrate leachate solutions did not contain significant concentrations of transuranic elements, so these solutions could be disposed as low-activity waste.

  19. Spectral and spectral-frequency methods of investigating atmosphereless bodies of the Solar system

    International Nuclear Information System (INIS)

    Busarev, Vladimir V; Prokof'eva-Mikhailovskaya, Valentina V; Bochkov, Valerii V

    2007-01-01

    A method of reflectance spectrophotometry of atmosphereless bodies of the Solar system, its specificity, and the means of eliminating basic spectral noise are considered. As a development, joining the method of reflectance spectrophotometry with the frequency analysis of observational data series is proposed. The combined spectral-frequency method allows identification of formations with distinctive spectral features, and estimations of their sizes and distribution on the surface of atmospherelss celestial bodies. As applied to investigations of asteroids 21 Lutetia and 4 Vesta, the spectral frequency method has given us the possibility of obtaining fundamentally new information about minor planets. (instruments and methods of investigation)

  20. Oxidation Resistance, Electrical and Thermal Conductivity, and Spectral Emittance of Fully Dense HfB2 and ZrB2 with SiC, TaSi2, and LaB6 Additives

    Science.gov (United States)

    2012-01-26

    of ZrB2-30 mol% SiC Electrically Heated Ribbons over 1-6 µm5 Spectral radiosities of direct electrically-heated ZrB2-30 mol% SiC specimens were mea...where RT (λ) is the spectral radiosity , h is Planck’s constant, k is Boltzmann’s constant, λ is wavelength, c is the speed of light, and T is the...Thus spectral radiosity measurements were performed at an angle normal to the ribbon surface. Specimens were loaded and removed from the chamber via an O

  1. Study on text mining algorithm for ultrasound examination of chronic liver diseases based on spectral clustering

    Science.gov (United States)

    Chang, Bingguo; Chen, Xiaofei

    2018-05-01

    Ultrasonography is an important examination for the diagnosis of chronic liver disease. The doctor gives the liver indicators and suggests the patient's condition according to the description of ultrasound report. With the rapid increase in the amount of data of ultrasound report, the workload of professional physician to manually distinguish ultrasound results significantly increases. In this paper, we use the spectral clustering method to cluster analysis of the description of the ultrasound report, and automatically generate the ultrasonic diagnostic diagnosis by machine learning. 110 groups ultrasound examination report of chronic liver disease were selected as test samples in this experiment, and the results were validated by spectral clustering and compared with k-means clustering algorithm. The results show that the accuracy of spectral clustering is 92.73%, which is higher than that of k-means clustering algorithm, which provides a powerful ultrasound-assisted diagnosis for patients with chronic liver disease.

  2. Rapidly Moving Divertor Plates In A Tokamak

    International Nuclear Information System (INIS)

    Zweben, S.

    2011-01-01

    It may be possible to replace conventional actively cooled tokamak divertor plates with a set of rapidly moving, passively cooled divertor plates on rails. These plates would absorb the plasma heat flux with their thermal inertia for ∼10-30 sec, and would then be removed from the vessel for processing. When outside the tokamak, these plates could be cooled, cleaned, recoated, inspected, and then returned to the vessel in an automated loop. This scheme could provide nearoptimal divertor surfaces at all times, and avoid the need to stop machine operation for repair of damaged or eroded plates. We describe various possible divertor plate designs and access geometries, and discuss an initial design for a movable and removable divertor module for NSTX-U.

  3. Removal mechanism of phosphate from aqueous solution by fly ash.

    Science.gov (United States)

    Lu, S G; Bai, S Q; Zhu, L; Shan, H D

    2009-01-15

    This work studied the effectiveness of fly ash in removing phosphate from aqueous solution and its related removal mechanism. The adsorption and precipitation of phosphate by fly ash were investigated separately in order to evaluate their role in the removal of phosphate. Results showed that the removal of phosphate by fly ash was rapid. The removal percentage of phosphate in the first 5min reached 68-96% of the maximum removal of phosphate by fly ash. The removal processes of phosphate by fly ash included a fast and large removal representing precipitation, then a slower and longer removal due to adsorption. The adsorption of phosphate on fly ash could be described well by Freundlich isotherm equation. The pH and Ca2+ concentration of fly ash suspension were decreased with the addition of phosphate, which suggests that calcium phosphate precipitation is a major mechanism of the phosphate removal. Comparison of the relative contribution of the adsorption and precipitation to the total removal of phosphate by fly ash showed that the adsorption accounted for 30-34% of the total removal of phosphate, depending on the content of CaO in fly ash. XRD patterns of the fly ash before and after phosphate adsorption revealed that phosphate salt (CaHPO4 x 2H2O) was formed in the adsorption process. Therefore, the removal of phosphate by fly ash can be attributed to the formation of phosphate precipitation as a brushite and the adsorption on hydroxylated oxides. The results suggested that the use of fly ash could be a promising solution to the removal of phosphate in the wastewater treatment and pollution control.

  4. Rapid estimation of organic nitrogen in oil shale wastewaters

    Energy Technology Data Exchange (ETDEWEB)

    Jones, B.M.; Harris, G.J.; Daughton, C.G.

    1984-03-01

    Many of the characteristics of oil shale process wastewaters (e.g., malodors, color, and resistance to biotreatment) are imparted by numerous nitrogen heterocycles and aromatic amines. For the frequent performance assessment of waste treatment procsses designed to remove these nitrogenous organic compounds, a rapid and colligative measurement of organic nitrogen is essential.

  5. Reflectance continuum removal spectral index tracking the xanthophyll cycle photoprotective reactions in Norway spruce needles

    Czech Academy of Sciences Publication Activity Database

    Kováč, Daniel; Navrátil, M.; Malenovský, Z.; Štroch, Michal; Špunda, Vladimír; Urban, Otmar

    2012-01-01

    Roč. 39, č. 12 (2012), s. 987-998 ISSN 1445-4408 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŽP(CZ) SP/2D1/70/08 Institutional support: RVO:67179843 Keywords : diurnal course * growth chambers * photosynthetic pigments composition * Picea abies * reflectance continuum removal * xanthophyll cycle Subject RIV: EH - Ecology, Behaviour Impact factor: 2.471, year: 2012

  6. [Rapid startup and nitrogen removal characteristic of anaerobic ammonium oxidation reactor in packed bed biofilm reactor with suspended carrier].

    Science.gov (United States)

    Chen, Sheng; Sun, De-zhi; Yu, Guang-lu

    2010-03-01

    Packed bed biofilm reactor with suspended carrier was used to cultivate ANAMMOX bacteria with sludge inoculums from WWTP secondary settler. The startup of ANAMMOX reactor was comparatively studied using high nitrogen loading method and low nitrogen loading method with aerobically biofilmed on the carrier, and the nitrogen removal characteristic was further investigated. The results showed that the reactor could be started up successfully within 90 days using low nitrogen loading method, the removal efficiencies of ammonium and nitrite were nearly 100% and the TN removal efficiencywas over 75% , however, the high nitrogen loading method was proved unsuccessfully for startup of ANAMMOX reactor probably because of the inhibition effect of high concentration of ammonium and nitrite. The pH value of effluent was slightly higher than the influent and the pH value can be used as an indicator for the process of ANAMMOX reaction. The packed bed ANAMMOX reactor with suspended carrier showed good characteristics of high nitrogen loading and high removal efficiency, 100% of removal efficiency could be achieved when the influent ammonium and nitrite concentration was lower than 800 mg/L.

  7. Contrast Enhanced Spectral Mammography: A Review.

    Science.gov (United States)

    Patel, Bhavika K; Lobbes, M B I; Lewin, John

    2018-02-01

    Contrast-enhanced spectral mammography (CESM) provides low-energy 2D mammographic images comparable to standard digital mammography and a post-contrast recombined image to assess tumor neovascularity similar to magnetic resonance imaging (MRI). The utilization of CESM in the United States is currently low but could increase rapidly given many potential indications for clinical use. This article discusses historical background and literature review of indications and diagnostic accuracy of CESM to date. CESM is a growing technique for breast cancer detection and diagnosis that has levels of sensitivity and specificity on par with contrast-enhanced breast MRI. Because of its similar performance and ease of implementation, CESM is being adopted for multiple indications previously reserved for MRI, such as problem-solving, disease extent in newly diagnosed patients, and evaluating the treatment response of neoadjuvant chemotherapy. Copyright © 2018 Elsevier Inc. All rights reserved.

  8. Estimation of spectral kurtosis

    Science.gov (United States)

    Sutawanir

    2017-03-01

    Rolling bearings are the most important elements in rotating machinery. Bearing frequently fall out of service for various reasons: heavy loads, unsuitable lubrications, ineffective sealing. Bearing faults may cause a decrease in performance. Analysis of bearing vibration signals has attracted attention in the field of monitoring and fault diagnosis. Bearing vibration signals give rich information for early detection of bearing failures. Spectral kurtosis, SK, is a parameter in frequency domain indicating how the impulsiveness of a signal varies with frequency. Faults in rolling bearings give rise to a series of short impulse responses as the rolling elements strike faults, SK potentially useful for determining frequency bands dominated by bearing fault signals. SK can provide a measure of the distance of the analyzed bearings from a healthy one. SK provides additional information given by the power spectral density (psd). This paper aims to explore the estimation of spectral kurtosis using short time Fourier transform known as spectrogram. The estimation of SK is similar to the estimation of psd. The estimation falls in model-free estimation and plug-in estimator. Some numerical studies using simulations are discussed to support the methodology. Spectral kurtosis of some stationary signals are analytically obtained and used in simulation study. Kurtosis of time domain has been a popular tool for detecting non-normality. Spectral kurtosis is an extension of kurtosis in frequency domain. The relationship between time domain and frequency domain analysis is establish through power spectrum-autocovariance Fourier transform. Fourier transform is the main tool for estimation in frequency domain. The power spectral density is estimated through periodogram. In this paper, the short time Fourier transform of the spectral kurtosis is reviewed, a bearing fault (inner ring and outer ring) is simulated. The bearing response, power spectrum, and spectral kurtosis are plotted to

  9. Spectral stratigraphy

    Science.gov (United States)

    Lang, Harold R.

    1991-01-01

    A new approach to stratigraphic analysis is described which uses photogeologic and spectral interpretation of multispectral remote sensing data combined with topographic information to determine the attitude, thickness, and lithology of strata exposed at the surface. The new stratigraphic procedure is illustrated by examples in the literature. The published results demonstrate the potential of spectral stratigraphy for mapping strata, determining dip and strike, measuring and correlating stratigraphic sequences, defining lithofacies, mapping biofacies, and interpreting geological structures.

  10. Efficient interruption of infection chains by targeted removal of central holdings in an animal trade network.

    Science.gov (United States)

    Büttner, Kathrin; Krieter, Joachim; Traulsen, Arne; Traulsen, Imke

    2013-01-01

    Centrality parameters in animal trade networks typically have right-skewed distributions, implying that these networks are highly resistant against the random removal of holdings, but vulnerable to the targeted removal of the most central holdings. In the present study, we analysed the structural changes of an animal trade network topology based on the targeted removal of holdings using specific centrality parameters in comparison to the random removal of holdings. Three different time periods were analysed: the three-year network, the yearly and the monthly networks. The aim of this study was to identify appropriate measures for the targeted removal, which lead to a rapid fragmentation of the network. Furthermore, the optimal combination of the removal of three holdings regardless of their centrality was identified. The results showed that centrality parameters based on ingoing trade contacts, e.g. in-degree, ingoing infection chain and ingoing closeness, were not suitable for a rapid fragmentation in all three time periods. More efficient was the removal based on parameters considering the outgoing trade contacts. In all networks, a maximum percentage of 7.0% (on average 5.2%) of the holdings had to be removed to reduce the size of the largest component by more than 75%. The smallest difference from the optimal combination for all three time periods was obtained by the removal based on out-degree with on average 1.4% removed holdings, followed by outgoing infection chain and outgoing closeness. The targeted removal using the betweenness centrality differed the most from the optimal combination in comparison to the other parameters which consider the outgoing trade contacts. Due to the pyramidal structure and the directed nature of the pork supply chain the most efficient interruption of the infection chain for all three time periods was obtained by using the targeted removal based on out-degree.

  11. Spectral unmixing: estimating partial abundances

    CSIR Research Space (South Africa)

    Debba, Pravesh

    2009-01-01

    Full Text Available techniques is complicated when considering very similar spectral signatures. Iron-bearing oxide/hydroxide/sulfate minerals have similar spectral signatures. The study focuses on how could estimates of abundances of spectrally similar iron-bearing oxide...

  12. Doubling the Spectrum of Time-Domain Induced Polarization: Removal of Harmonic Noise and Self-Potential Drift

    Science.gov (United States)

    Fiandaca, G.; Olsson, P. I.; Auken, E.; Larsen, J. J.; Maurya, P. K.; Dahlin, T.

    2015-12-01

    The extraction of spectral information in the inversion process of time-domain (TD) induced polarization (IP) data is changing the use of the IP method. Data interpretation is evolving from a qualitative description of the soil, able only to discriminate the presence of contrasts in chargeability parameters, towards a quantitative analysis of the investigated media, which allows soil-type characterization. Two major limitations restrict the extraction of the spectral information of TDIP data in the field: i) the difficulty of acquiring reliable early-time measurements, in the millisecond range and ii) the self-potential drift in the measured potentials distorting the shape of the late time IP decays, in the second range. For measuring at early-times, we developed a new method for removing the powerline noise contained in the data through a model-based approach, localizing the fundamental frequency of the powerline signal in the full-waveform IP recordings. By this, we cancel both the fundamental signal and its harmonics. This noise cancellation allows the use of earlier and narrower gates, down to a few milliseconds after the current turn-off. Even earlier gates can be measured but they will be inductively "contaminated" which we at present want to avoid. A proper removal of the self-potential drift present between the potential electrodes is essential for preserving the shape of the TD decays, especially for late times. Usually constant or linear drift-removal algorithms are used, but these algorithms fail in removing the background potentials due to the polarization of the electrodes previously used for current injection. We developed a drift-removal scheme that model the polarization effect and efficiently allows for preserving the shape of the IP decays. The removal of both the harmonic noise and self-potential drift allows for doubling the usable range of TDIP data to more than three decades in time (corresponding to three decays in frequency), and will

  13. A Simple and Rapid Complexometric Determination of Thallium(III ...

    African Journals Online (AJOL)

    A simple, rapid and selective complexometric method is proposed for the determination of thallium(III), using mercaptoethane(EtSH) as demasking agent. The sample solution containing Tl(III) is first complexed with excess EDTA and the surplus EDTA is removed by titration at pH 5–6 with zinc sulphate solution using ...

  14. Film thickness measurement based on nonlinear phase analysis using a Linnik microscopic white-light spectral interferometer.

    Science.gov (United States)

    Guo, Tong; Chen, Zhuo; Li, Minghui; Wu, Juhong; Fu, Xing; Hu, Xiaotang

    2018-04-20

    Based on white-light spectral interferometry and the Linnik microscopic interference configuration, the nonlinear phase components of the spectral interferometric signal were analyzed for film thickness measurement. The spectral interferometric signal was obtained using a Linnik microscopic white-light spectral interferometer, which includes the nonlinear phase components associated with the effective thickness, the nonlinear phase error caused by the double-objective lens, and the nonlinear phase of the thin film itself. To determine the influence of the effective thickness, a wavelength-correction method was proposed that converts the effective thickness into a constant value; the nonlinear phase caused by the effective thickness can then be determined and subtracted from the total nonlinear phase. A method for the extraction of the nonlinear phase error caused by the double-objective lens was also proposed. Accurate thickness measurement of a thin film can be achieved by fitting the nonlinear phase of the thin film after removal of the nonlinear phase caused by the effective thickness and by the nonlinear phase error caused by the double-objective lens. The experimental results demonstrated that both the wavelength-correction method and the extraction method for the nonlinear phase error caused by the double-objective lens improve the accuracy of film thickness measurements.

  15. Assessment of relevant hepatic steatosis in obese adolescents by rapid fat-selective GRE imaging with spatial-spectral excitation: a quantitative comparison with spectroscopic findings

    International Nuclear Information System (INIS)

    Springer, Fabian; Schick, Fritz; Ehehalt, Stefan; Binder, Gerhard; Sommer, Julia; Ballweg, Verena; Machann, Juergen; Claussen, Claus D.

    2011-01-01

    To test the feasibility of fat-selective GRE imaging using a spectral-spatial excitation technique for determination of intrahepatic lipid content (IHL) in obese adolescents. Fat-selective MR imaging (1.5 T) was applied to record a single axial slice through a representative liver region within a single breath-hold. The sequence uses six equidistant slice-selective excitation pulses with binomial amplitude ratios to achieve high selectivity for lipid signals after appropriate shimming. IHL MRI content was quantified using signal intensity of adjacent subcutaneous adipose tissue. As the gold standard for IHL quantification, single-voxel stimulated echo magnetic resonance spectroscopy (MRS) was applied. IHL MRS was quantified using the water peak as a reference. Forty-five MR examinations could be performed, and IHL MRS content ranged from 0.7% to 19.1%. Results from MRS and fat-selective imaging correlated well with Spearman coefficients between r = 0.78 and r = 0.86. There were no relevant regional differences in IHL within the liver parenchyma (p > 0.6359). Fat-selective imaging was able to reliably identify patients with IHL content above 5% with positive/negative likelihood ratio of 11.8 and 0.05, respectively. Fat-selective MR imaging provides both a reliable and a convenient method of rapidly quantifying IHL content in obese adolescents. (orig.)

  16. Introduction to spectral theory

    CERN Document Server

    Levitan, B M

    1975-01-01

    This monograph is devoted to the spectral theory of the Sturm- Liouville operator and to the spectral theory of the Dirac system. In addition, some results are given for nth order ordinary differential operators. Those parts of this book which concern nth order operators can serve as simply an introduction to this domain, which at the present time has already had time to become very broad. For the convenience of the reader who is not familar with abstract spectral theory, the authors have inserted a chapter (Chapter 13) in which they discuss this theory, concisely and in the main without proofs, and indicate various connections with the spectral theory of differential operators.

  17. Integrated Spectral Energy Distributions and Absorption Feature Indices of Single Stellar Populations

    OpenAIRE

    Zhang, Fenghui; Han, Zhanwen; Li, Lifang; Hurley, Jarrod R.

    2004-01-01

    Using evolutionary population synthesis, we present integrated spectral energy distributions and absorption-line indices defined by the Lick Observatory image dissector scanner (referred to as Lick/IDS) system, for an extensive set of instantaneous burst single stellar populations (SSPs). The ages of the SSPs are in the range 1-19 Gyr and the metallicities [Fe/H] are in the range -2.3 - 0.2. Our models use the rapid single stellar evolution algorithm of Hurley, Pols and Tout for the stellar e...

  18. Robust power spectral estimation for EEG data.

    Science.gov (United States)

    Melman, Tamar; Victor, Jonathan D

    2016-08-01

    Typical electroencephalogram (EEG) recordings often contain substantial artifact. These artifacts, often large and intermittent, can interfere with quantification of the EEG via its power spectrum. To reduce the impact of artifact, EEG records are typically cleaned by a preprocessing stage that removes individual segments or components of the recording. However, such preprocessing can introduce bias, discard available signal, and be labor-intensive. With this motivation, we present a method that uses robust statistics to reduce dependence on preprocessing by minimizing the effect of large intermittent outliers on the spectral estimates. Using the multitaper method (Thomson, 1982) as a starting point, we replaced the final step of the standard power spectrum calculation with a quantile-based estimator, and the Jackknife approach to confidence intervals with a Bayesian approach. The method is implemented in provided MATLAB modules, which extend the widely used Chronux toolbox. Using both simulated and human data, we show that in the presence of large intermittent outliers, the robust method produces improved estimates of the power spectrum, and that the Bayesian confidence intervals yield close-to-veridical coverage factors. The robust method, as compared to the standard method, is less affected by artifact: inclusion of outliers produces fewer changes in the shape of the power spectrum as well as in the coverage factor. In the presence of large intermittent outliers, the robust method can reduce dependence on data preprocessing as compared to standard methods of spectral estimation. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. [Analysis of sensitive spectral bands for burning status detection using hyper-spectral images of Tiangong-01].

    Science.gov (United States)

    Qin, Xian-Lin; Zhu, Xi; Yang, Fei; Zhao, Kai-Rui; Pang, Yong; Li, Zeng-Yuan; Li, Xu-Zhi; Zhang, Jiu-Xing

    2013-07-01

    To obtain the sensitive spectral bands for detection of information on 4 kinds of burning status, i. e. flaming, smoldering, smoke, and fire scar, with satellite data, analysis was conducted to identify suitable satellite spectral bands for detection of information on these 4 kinds of burning status by using hyper-spectrum images of Tiangong-01 (TG-01) and employing a method combining statistics and spectral analysis. The results show that: in the hyper-spectral images of TG-01, the spectral bands differ obviously for detection of these 4 kinds of burning status; in all hyper-spectral short-wave infrared channels, the reflectance of flaming is higher than that of all other 3 kinds of burning status, and the reflectance of smoke is the lowest; the reflectance of smoke is higher than that of all other 3 kinds of burning status in the channels corresponding to hyper-spectral visible near-infrared and panchromatic sensors. For spectral band selection, more suitable spectral bands for flaming detection are 1 000.0-1 956.0 and 2 020.0-2 400.0 nm; the suitable spectral bands for identifying smoldering are 930.0-1 000.0 and 1 084.0-2 400.0 nm; the suitable spectral bands for smoke detection is in 400.0-920.0 nm; for fire scar detection, it is suitable to select bands with central wavelengths of 900.0-930.0 and 1 300.0-2 400.0 nm, and then to combine them to construct a detection model.

  20. Spectral Decomposition Algorithm (SDA)

    Data.gov (United States)

    National Aeronautics and Space Administration — Spectral Decomposition Algorithm (SDA) is an unsupervised feature extraction technique similar to PCA that was developed to better distinguish spectral features in...

  1. NASA MSFC Electrostatic Levitator (ESL) Rapid Quench System

    Science.gov (United States)

    SanSoucie, Michael P.; Craven, Paul D.

    2014-01-01

    Electrostatic levitation, a form of containerless processing, is an important tool in materials research. Levitated specimens are free from contact with a container; therefore, heterogeneous nucleation on container walls is not possible. This allows studies of deeply undercooled melts. Furthermore, studies of high-temperature, highly reactive materials are also possible. Studies of the solidification and crystallization of undercooled melts is vital to the understanding of microstructure development, particularly the formation of alloys with unique properties by rapid solidification. The NASA Marshall Space Flight Center (MSFC) Electrostatic Levitator (ESL) lab has recently been upgraded to allow for rapid quenching of levitated materials. The ESL Rapid Quench System uses a small crucible-like vessel that can be partially filled with a low melting point material, such as a Gallium alloy, as a quench medium. An undercooled sample can be dropped into the vessel to rapidly quench the sample. A carousel with nine vessels sits below the bottom electrode assembly. This system allows up to nine rapid quenches before having to break vacuum and remove the vessels. This new Rapid Quench System will allow materials science studies of undercooled materials and new materials development. In this presentation, the system is described and initial results are presented.

  2. More disposable than ever? Consequences of non-removable batteries in mobile devices

    NARCIS (Netherlands)

    Bakker, C.A.; Kuijer, L.

    2014-01-01

    Mobile devices like smart phones, tablet computers and ultraportable laptops are experiencing rapid worldwide market growth and have relatively short lifespans. Recently, embedded (non-removable) batteries were introduced that cannot be replaced by consumers. This study traces the environmental and

  3. A distributed microcomputer-controlled system for data acquisition and power spectral analysis of EEG.

    Science.gov (United States)

    Vo, T D; Dwyer, G; Szeto, H H

    1986-04-01

    A relatively powerful and inexpensive microcomputer-based system for the spectral analysis of the EEG is presented. High resolution and speed is achieved with the use of recently available large-scale integrated circuit technology with enhanced functionality (INTEL Math co-processors 8087) which can perform transcendental functions rapidly. The versatility of the system is achieved with a hardware organization that has distributed data acquisition capability performed by the use of a microprocessor-based analog to digital converter with large resident memory (Cyborg ISAAC-2000). Compiled BASIC programs and assembly language subroutines perform on-line or off-line the fast Fourier transform and spectral analysis of the EEG which is stored as soft as well as hard copy. Some results obtained from test application of the entire system in animal studies are presented.

  4. The rapid measurement of soil carbon stock using near-infrared technology

    Science.gov (United States)

    Kusumo, B. H.; Sukartono; Bustan

    2018-03-01

    As a soil pool stores carbon (C) three times higher than an atmospheric pool, the depletion of C stock in the soil will significantly increase the concentration of CO2 in the atmosphere, causing global warming. However, the monitoring or measurement of soil C stock using conventional procedures is time-consuming and expensive. So it requires a rapid and non-destructive technique that is simple and does not need chemical substances. This research is aimed at testing whether near-infrared (NIR) technology is able to rapidly measure C stock in the soil. Soil samples were collected from an agricultural land at the sub-district of Kayangan, North Lombok, Indonesia. The coordinates of the samples were recorded. Parts of the samples were analyzed using conventional procedure (Walkley and Black) and some other parts were scanned using near-infrared spectroscopy (NIRS) for soil spectral collection. Partial Least Square Regression (PLSR) was used to develop models from soil C data measured by conventional analysis and from spectral data scanned by NIRS. The best model was moderately successful to measure soil C stock in the study area in North Lombok. This indicates that the NIR technology can be further used to monitor the change of soil C stock in the soil.

  5. Spectral features based tea garden extraction from digital orthophoto maps

    Science.gov (United States)

    Jamil, Akhtar; Bayram, Bulent; Kucuk, Turgay; Zafer Seker, Dursun

    2018-05-01

    The advancements in the photogrammetry and remote sensing technologies has made it possible to extract useful tangible information from data which plays a pivotal role in various application such as management and monitoring of forests and agricultural lands etc. This study aimed to evaluate the effectiveness of spectral signatures for extraction of tea gardens from 1 : 5000 scaled digital orthophoto maps obtained from Rize city in Turkey. First, the normalized difference vegetation index (NDVI) was derived from the input images to suppress the non-vegetation areas. NDVI values less than zero were discarded and the output images was normalized in the range 0-255. Individual pixels were then mapped into meaningful objects using global region growing technique. The resulting image was filtered and smoothed to reduce the impact of noise. Furthermore, geometrical constraints were applied to remove small objects (less than 500 pixels) followed by morphological opening operator to enhance the results. These objects served as building blocks for further image analysis. Finally, for the classification stage, a range of spectral values were empirically calculated for each band and applied on candidate objects to extract tea gardens. For accuracy assessment, we employed an area based similarity metric by overlapping obtained tea garden boundaries with the manually digitized tea garden boundaries created by experts of photogrammetry. The overall accuracy of the proposed method scored 89 % for tea gardens from 10 sample orthophoto maps. We concluded that exploiting the spectral signatures using object based analysis is an effective technique for extraction of dominant tree species from digital orthophoto maps.

  6. Directional and Spectral Irradiance in Ocean Models: Effects on Simulated Global Phytoplankton, Nutrients, and Primary Production

    Science.gov (United States)

    Gregg, Watson W.; Rousseaux, Cecile S.

    2016-01-01

    The importance of including directional and spectral light in simulations of ocean radiative transfer was investigated using a coupled biogeochemical-circulation-radiative model of the global oceans. The effort focused on phytoplankton abundances, nutrient concentrations and vertically-integrated net primary production. The importance was approached by sequentially removing directional (i.e., direct vs. diffuse) and spectral irradiance and comparing results of the above variables to a fully directionally and spectrally-resolved model. In each case the total irradiance was kept constant; it was only the pathways and spectral nature that were changed. Assuming all irradiance was diffuse had negligible effect on global ocean primary production. Global nitrate and total chlorophyll concentrations declined by about 20% each. The largest changes occurred in the tropics and sub-tropics rather than the high latitudes, where most of the irradiance is already diffuse. Disregarding spectral irradiance had effects that depended upon the choice of attenuation wavelength. The wavelength closest to the spectrally-resolved model, 500 nm, produced lower nitrate (19%) and chlorophyll (8%) and higher primary production (2%) than the spectral model. Phytoplankton relative abundances were very sensitive to the choice of non-spectral wavelength transmittance. The combined effects of neglecting both directional and spectral irradiance exacerbated the differences, despite using attenuation at 500 nm. Global nitrate decreased 33% and chlorophyll decreased 24%. Changes in phytoplankton community structure were considerable, representing a change from chlorophytes to cyanobacteria and coccolithophores. This suggested a shift in community function, from light-limitation to nutrient limitation: lower demands for nutrients from cyanobacteria and coccolithophores favored them over the more nutrient-demanding chlorophytes. Although diatoms have the highest nutrient demands in the model, their

  7. Application of a regularized model inversion system (REGFLEC) to multi-temporal RapidEye imagery for retrieving vegetation characteristics

    KAUST Repository

    Houborg, Rasmus; McCabe, Matthew

    2015-01-01

    to time-series of 5 m resolution multi-spectral RapidEye data is demonstrated over an irrigated agricultural region in central Saudi Arabia, showcasing the value of satellite-derived crop information at this fine scale for precision management. Validation

  8. The RAPID protocol enhances patient recovery after both laparoscopic and open colorectal resections.

    LENUS (Irish Health Repository)

    Lloyd, G M

    2010-06-01

    Enhanced recovery after surgery (ERAS) programs can accelerate recovery and shorten the hospital stay after colorectal resections. The RAPID (remove, ambulate, postoperative analgesia, introduce diet) protocol is a simplified ERAS program that consists of a simplified, user-friendly single-page pro forma schedule. This study aimed to evaluate the impact of the RAPID protocol on patients undergoing both laparoscopic and open colorectal resections in two specialized colorectal units.

  9. Solutions to microplastic pollution - Removal of microplastics from wastewater effluent with advanced wastewater treatment technologies.

    Science.gov (United States)

    Talvitie, Julia; Mikola, Anna; Koistinen, Arto; Setälä, Outi

    2017-10-15

    Conventional wastewater treatment with primary and secondary treatment processes efficiently remove microplastics (MPs) from the wastewater. Despite the efficient removal, final effluents can act as entrance route of MPs, given the large volumes constantly discharged into the aquatic environments. This study investigated the removal of MPs from effluent in four different municipal wastewater treatment plants utilizing different advanced final-stage treatment technologies. The study included membrane bioreactor treating primary effluent and different tertiary treatment technologies (discfilter, rapid sand filtration and dissolved air flotation) treating secondary effluent. The MBR removed 99.9% of MPs during the treatment (from 6.9 to 0.005 MP L -1 ), rapid sand filter 97% (from 0.7 to 0.02 MP L -1 ), dissolved air flotation 95% (from 2.0 to 0.1 MP L -1 ) and discfilter 40-98.5% (from 0.5 - 2.0 to 0.03-0.3 MP L -1 ) of the MPs during the treatment. Our study shows that with advanced final-stage wastewater treatment technologies WWTPs can substantially reduce the MP pollution discharged from wastewater treatment plants into the aquatic environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Examining spectral variations in localized lunar dark mantle deposits

    Science.gov (United States)

    Jawin, Erica; Besse, Sebastien; Gaddis, Lisa R.; Sunshine, Jessica; Head, James W.; Mazrouei, Sara

    2015-01-01

    The localized lunar dark mantle deposits (DMDs) in Alphonsus, J. Herschel, and Oppenheimer craters were analyzed using visible-near-infrared spectroscopy data from the Moon Mineralogy Mapper. Spectra of these localized DMDs were analyzed for compositional and mineralogical variations within the deposits and were compared with nearby mare basalt units. Spectra of the three localized DMDs exhibited mafic absorption features indicating iron-rich compositions, although the DMDs were spectrally distinct from nearby mare basalts. All of the DMDs contained spectral signatures of glassy materials, suggesting the presence of volcanic glass in varying concentrations across the individual deposits. In addition, the albedo and spectral signatures were variable within the Alphonsus and Oppenheimer crater DMDs, suggesting variable deposit thickness and/or variations in the amount of mixing with the local substrate. Two previously unidentified localized DMDs were discovered to the northeast of Oppenheimer crater. The identification of high concentrations of volcanic glass in multiple localized DMDs in different locations suggests that the distribution of volcanic glass across the lunar surface is much more widespread than has been previously documented. The presence of volcanic glass implies an explosive, vulcanian eruption style for localized DMDs, as this allows volcanic glass to rapidly quench, inhibiting crystallization, compared to the larger hawaiian-style eruptions typical of regional DMD emplacement where black beads indicate a higher degree of crystallization. Improved understanding of the local and global distributions of volcanic glass in lunar DMDs will further constrain lunar degassing and compositional evolution throughout lunar volcanic history.

  11. The structure of turbulence in a rapid tidal flow.

    Science.gov (United States)

    Milne, I A; Sharma, R N; Flay, R G J

    2017-08-01

    The structure of turbulence in a rapid tidal flow is characterized through new observations of fundamental statistical properties at a site in the UK which has a simple geometry and sedate surface wave action. The mean flow at the Sound of Islay exceeded 2.5 m s -1 and the turbulent boundary layer occupied the majority of the water column, with an approximately logarithmic mean velocity profile identifiable close to the seabed. The anisotropic ratios, spectral scales and higher-order statistics of the turbulence generally agree well with values reported for two-dimensional open channels in the laboratory and other tidal channels, therefore providing further support for the application of universal models. The results of the study can assist in developing numerical models of turbulence in rapid tidal flows such as those proposed for tidal energy generation.

  12. Optimization of spectral printer modeling based on a modified cellular Yule-Nielsen spectral Neugebauer model.

    Science.gov (United States)

    Liu, Qiang; Wan, Xiaoxia; Xie, Dehong

    2014-06-01

    The study presented here optimizes several steps in the spectral printer modeling workflow based on a cellular Yule-Nielsen spectral Neugebauer (CYNSN) model. First, a printer subdividing method was developed that reduces the number of sub-models while maintaining the maximum device gamut. Second, the forward spectral prediction accuracy of the CYNSN model for each subspace of the printer was improved using back propagation artificial neural network (BPANN) estimated n values. Third, a sequential gamut judging method, which clearly reduced the complexity of the optimal sub-model and cell searching process during printer backward modeling, was proposed. After that, we further modified the use of the modeling color metric and comprehensively improved the spectral and perceptual accuracy of the spectral printer model. The experimental results show that the proposed optimization approaches provide obvious improvements in aspects of the modeling accuracy or efficiency for each of the corresponding steps, and an overall improvement of the optimized spectral printer modeling workflow was also demonstrated.

  13. Cadmium ion removal using biosorbents derived from fruit peel wastes

    Directory of Open Access Journals (Sweden)

    Wanna Saikaew

    2009-11-01

    Full Text Available The ability of fruit peel wastes, corn, durian, pummelo, and banana, to remove cadmium ions from aqueous solution by biosorption were investigated. The experiments were carried out by batch method at 25oC. The influence of particle sizes, solution pH, and initial cadmium ion concentrations were evaluated on the biosorption studies. The result showed that banana peel had the highest cadmium ions removal followed by durian, pummelo, and corn peels at cadmium ions removal of 73.15, 72.17, 70.56, and 51.22%, respectively. There was a minimal effect when using different particle sizes of corn peel as biosorbent, while the particle size of the others had no influence on the removal of cadmium ions. The cadmium ions removal increased significantly as the pH of the solution increased rapidly from 1 to 5. At pH 5, the cadmium ions removal reached a maximum value. The equilibrium process was best described by the Langmuir isotherms, with maximum biosorption capacities of durian, pummelo, and banana peel of 18.55, 21.83, and 20.88 mg/g respectively. Fourier Transform Infrared Spectroscopy revealed that carboxyl, hydroxyl, and amide groups on the fruit peels’ surface and these groups were involved in the adsorption of the cadmium ions.

  14. A COMPARISON OF HAZE REMOVAL ALGORITHMS AND THEIR IMPACTS ON CLASSIFICATION ACCURACY FOR LANDSAT IMAGERY

    Directory of Open Access Journals (Sweden)

    Yang Xiao

    Full Text Available The quality of Landsat images in humid areas is considerably degraded by haze in terms of their spectral response pattern, which limits the possibility of their application in using visible and near-infrared bands. A variety of haze removal algorithms have been proposed to correct these unsatisfactory illumination effects caused by the haze contamination. The purpose of this study was to illustrate the difference of two major algorithms (the improved homomorphic filtering (HF and the virtual cloud point (VCP for their effectiveness in solving spatially varying haze contamination, and to evaluate the impacts of haze removal on land cover classification. A case study with exploiting large quantities of Landsat TM images and climates (clear and haze in the most humid areas in China proved that these haze removal algorithms both perform well in processing Landsat images contaminated by haze. The outcome of the application of VCP appears to be more similar to the reference images compared to HF. Moreover, the Landsat image with VCP haze removal can improve the classification accuracy effectively in comparison to that without haze removal, especially in the cloudy contaminated area

  15. Phonological, temporal and spectral processing in vowel length discrimination is impaired in German primary school children with developmental dyslexia.

    Science.gov (United States)

    Steinbrink, Claudia; Klatte, Maria; Lachmann, Thomas

    2014-11-01

    It is still unclear whether phonological processing deficits are the underlying cause of developmental dyslexia, or rather a consequence of basic auditory processing impairments. To avoid methodological confounds, in the current study the same task and stimuli of comparable complexity were used to investigate both phonological and basic auditory (temporal and spectral) processing in dyslexia. German dyslexic children (Grades 3 and 4) were compared to age- and grade-matched controls in a vowel length discrimination task with three experimental conditions: In a phonological condition, natural vowels were used, differing both with respect to temporal and spectral information (in German, vowel length is phonemic, and vowel length differences are characterized by both temporal and spectral information). In a temporal condition, spectral information differentiating between the two vowels of a pair was eliminated, whereas in a spectral condition, temporal differences were removed. As performance measure, the sensitivity index d' was computed. At the group level, dyslexic children's performance was inferior to that of controls for phonological as well as temporal and spectral vowel length discrimination. At an individual level, nearly half of the dyslexic sample was characterized by deficits in all three conditions, but there were also some children showing no deficits at all. These results reveal on the one hand that phonological processing deficits in dyslexia may stem from impairments in processing temporal and spectral information in the speech signal. On the other hand they indicate, however, that not all dyslexic children might be characterized by phonological or auditory processing deficits. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Water hyacinths and alligator weeds for removal of silver, cobalt, and strontium from polluted waters

    Science.gov (United States)

    Wolverton, B. C.; Mcdonald, R. C.

    1975-01-01

    Water hyacinths and alligator weeds demonstrated the ability to rapidly remove heavy metals from an aqueous system by root absorption and concentration. Water hyacinths demonstrated the ability to remove 0.439 mg of silver, 0.568 mg of cobalt, and 0.544 mg of strontium in an ionized form per gram of dry plant material in a 24-hour period. Alligator weeds removed a maximum of 0.439 mg of silver, 0.130 mg of cobalt, and 0.161 mg of strontium per gram of dry plant material per day.

  17. A New Spectral Local Linearization Method for Nonlinear Boundary Layer Flow Problems

    Directory of Open Access Journals (Sweden)

    S. S. Motsa

    2013-01-01

    Full Text Available We propose a simple and efficient method for solving highly nonlinear systems of boundary layer flow problems with exponentially decaying profiles. The algorithm of the proposed method is based on an innovative idea of linearizing and decoupling the governing systems of equations and reducing them into a sequence of subsystems of differential equations which are solved using spectral collocation methods. The applicability of the proposed method, hereinafter referred to as the spectral local linearization method (SLLM, is tested on some well-known boundary layer flow equations. The numerical results presented in this investigation indicate that the proposed method, despite being easy to develop and numerically implement, is very robust in that it converges rapidly to yield accurate results and is more efficient in solving very large systems of nonlinear boundary value problems of the similarity variable boundary layer type. The accuracy and numerical stability of the SLLM can further be improved by using successive overrelaxation techniques.

  18. Pleiades rapid rotators - evidence for an evolutionary sequence

    International Nuclear Information System (INIS)

    Butler, R.P.; Marcy, G.W.; Cohen, R.D.; Duncan, D.K.; California Univ., La Jolla; Space Telescope Science Institute, Baltimore, MD)

    1987-01-01

    Four rapidly rotating early-K dwarfs in the Pleiades are shown to contain an order of magnitude more Li than four slow rotators of the same spectral type, as would be expected if they were systematically younger. This supports the idea that late-type stars first arrive on the main sequence with V(rot) greater than about 100 km/s, that they spin down to V(rot) less than about 10 km/s in 10 to the 7th to 10 to the 8th yr, and that the Pleiades lower main sequence shows such an age spread. 14 references

  19. Quenching of the OH and nitrogen molecular emission by methane addition in an Ar capacitively coupled plasma to remove spectral interference in lead determination by atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Frentiu, T., E-mail: ftibi@chem.ubbcluj.r [Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos 11, 400028 Cluj-Napoca (Romania); Ponta, M., E-mail: mponta@chem.ubbcluj.r [Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos 11, 400028 Cluj-Napoca (Romania); Mihaltan, A.I., E-mail: alinblaj2005@yahoo.co [National Institute for Research and Development of Optoelectronics Bucharest - Research Institute for Analytical Instrumentation, Donath 67, 400293 Cluj-Napoca (Romania); Darvasi, E., E-mail: edarvasi@chem.ubbcluj.r [Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos 11, 400028 Cluj-Napoca (Romania); Frentiu, M., E-mail: frentiu.maria@yahoo.co [National Institute for Research and Development of Optoelectronics Bucharest - Research Institute for Analytical Instrumentation, Donath 67, 400293 Cluj-Napoca (Romania); Cordos, E., E-mail: emilcordos@gmail.co [National Institute for Research and Development of Optoelectronics Bucharest - Research Institute for Analytical Instrumentation, Donath 67, 400293 Cluj-Napoca (Romania)

    2010-07-15

    A new method is proposed to remove the spectral interference on elements in atomic fluorescence spectrometry by quenching of the molecular emission of the OH radical (A{sup 2{Sigma}+} {yields} X{sup 2{Pi}}) and N{sub 2} second positive system (C{sup 3{Pi}}{sub u} {yields} B{sup 3{Sigma}}{sub g}) in the background spectrum of medium power Ar plasmas. The experiments were carried out in a radiofrequency capacitively coupled plasma (275 W, 27.12 MHz) by CH{sub 4} addition. The quenching is the result of the high affinity of OH radical for a hydrogen atom from the CH{sub 4} molecule and the collisions of the second kind between nitrogen excited molecules and CH{sub 4}, respectively. The decrease of the emission of N{sub 2} second positive system in the presence of CH{sub 4} is also the result of the deactivation of the metastable argon atoms that could excite the nitrogen molecules. For flow rates of 0.7 l min{sup -1} Ar with addition of 7.5 ml min{sup -1} CH{sub 4}, the molecular emission of OH and N{sub 2} was completely removed from the plasma jet spectrum at viewing heights above 60 mm. The molecular emission associated to CH and CH{sub 2} species was not observed in the emission spectrum of Ar/CH{sub 4} plasma in the ultraviolet range. The method was experimented for the determination of Pb at 283.31 nm by atomic fluorescence spectrometry with electrodeless discharge lamp and a multichannel microspectrometer. The detection limit was 35 ng ml{sup -1}, 2-3 times better than in atomic emission spectrometry using the same plasma source, and similar to that in hollow cathode lamp microwave plasma torch atomic fluorescence spectrometry.

  20. [Rapid multi-elemental analysis on four precious Tibetan medicines based on LIBS technique].

    Science.gov (United States)

    Liu, Xiao-na; Shi, Xin-yuan; Jia, Shuai-yun; Zhao, Na; Wu, Zhi-sheng; Qiao, Yan-jiang

    2015-06-01

    The laser-induced breakdown spectroscopy (LIBS) was applied to perform a qualitative elementary analysis on four precious Tibetan medicines, i. e. Renqing Mangjue, Renqing Changjue, 25-herb coral pills and 25-herb pearl pills. The specific spectra of the four Tibetan medicines were established. In the experiment, Nd: YAG and 1 064 nm-baseband pulse laser were adopted to collect the spectra. A laser beam focused on the surface of the samples to generate plasma. Its spectral signal was detected by using spectrograph. Based on the National Institute of Standard and Technology (NIST) database, LIBS spectral lines were indentified. The four Tibetan medicines mainly included Ca, Na, K, Mg and other elements and C-N molecular band. Specifically, Fe was detected in Renqing Changjue and 25-herb pearl pills; heavy mental elements Hg and Cu were shown in Renqing Mangjue and Renqing Changjue; Ag was found in Renqing Changjue. The results demonstrated that LIBS is a reliable and rapid multi-element analysis on the four Tibetan medicines. With Real-time, rapid and nondestructive advantages, LIBS has a wide application prospect in the element analysis on ethnic medicines.

  1. Face mask removal is safer than helmet removal for emergent airway access in American football.

    Science.gov (United States)

    Swartz, Erik E; Mihalik, Jason P; Beltz, Nora M; Day, Molly A; Decoster, Laura C

    2014-06-01

    In cases of possible cervical spine injury, medical professionals must be prepared to achieve rapid airway access while concurrently restricting cervical spine motion. Face mask removal (FMR), rather than helmet removal (HR), is recommended to achieve this. However, no studies have been reported that compare FMR directly with HR. The purpose of this study was to compare motion, time, and perceived difficulty in two commonly used American football helmets between FMR and HR techniques, and when helmet air bladders were deflated before HR compared with inflated scenarios. The study incorporated a repeated measures design and was performed in a controlled laboratory setting. Participants included 22 certified athletic trainers (15 men and seven women; mean age, 33.9±10.5 years; mean experience, 11.4±10.0 years; mean height, 172±9.4 cm; mean mass, 76.7±14.9 kg). All participants were free from upper extremity or central nervous system pathology for 6 months and provided informed consent. Dependent variables included head excursion in degrees (computed by subtracting the minimum position from the maximum position) in each of the three planes (sagittal, frontal, transverse), time to complete the required task, and ratings of perceived exertion. To address our study purposes, we used two-by-two repeated-measures analysis of variance (removal technique×helmet type, helmet type×deflation status) for each dependent variable. Independent variables consisted of removal technique (FMR and HR), helmet type (Riddell Revolution IQ [RIQ] and VSR4), and helmet deflation status (deflated [D], inflated, [I]). After familiarization, participants conducted two successful trials for each of six conditions in random order (RIQ-FMR, VSR4-FMR, RIQ-HR-D, VSR4-HR-D, RIQ-HR-I, and VSR4-HR-I). Face masks, helmets, and shoulder pads were removed from a live model wearing a properly fitted helmet and shoulder pads. The participant and an investigator stabilized the model's head. A six

  2. Spectral radius of graphs

    CERN Document Server

    Stevanovic, Dragan

    2015-01-01

    Spectral Radius of Graphs provides a thorough overview of important results on the spectral radius of adjacency matrix of graphs that have appeared in the literature in the preceding ten years, most of them with proofs, and including some previously unpublished results of the author. The primer begins with a brief classical review, in order to provide the reader with a foundation for the subsequent chapters. Topics covered include spectral decomposition, the Perron-Frobenius theorem, the Rayleigh quotient, the Weyl inequalities, and the Interlacing theorem. From this introduction, the

  3. Spectral L2/L1 norm: A new perspective for spectral kurtosis for characterizing non-stationary signals

    Science.gov (United States)

    Wang, Dong

    2018-05-01

    Thanks to the great efforts made by Antoni (2006), spectral kurtosis has been recognized as a milestone for characterizing non-stationary signals, especially bearing fault signals. The main idea of spectral kurtosis is to use the fourth standardized moment, namely kurtosis, as a function of spectral frequency so as to indicate how repetitive transients caused by a bearing defect vary with frequency. Moreover, spectral kurtosis is defined based on an analytic bearing fault signal constructed from either a complex filter or Hilbert transform. On the other hand, another attractive work was reported by Borghesani et al. (2014) to mathematically reveal the relationship between the kurtosis of an analytical bearing fault signal and the square of the squared envelope spectrum of the analytical bearing fault signal for explaining spectral correlation for quantification of bearing fault signals. More interestingly, it was discovered that the sum of peaks at cyclic frequencies in the square of the squared envelope spectrum corresponds to the raw 4th order moment. Inspired by the aforementioned works, in this paper, we mathematically show that: (1) spectral kurtosis can be decomposed into squared envelope and squared L2/L1 norm so that spectral kurtosis can be explained as spectral squared L2/L1 norm; (2) spectral L2/L1 norm is formally defined for characterizing bearing fault signals and its two geometrical explanations are made; (3) spectral L2/L1 norm is proportional to the square root of the sum of peaks at cyclic frequencies in the square of the squared envelope spectrum; (4) some extensions of spectral L2/L1 norm for characterizing bearing fault signals are pointed out.

  4. EVALUATION OF VARIOUS SPECTRAL INPUTS FOR ESTIMATION OF FOREST BIOCHEMICAL AND STRUCTURAL PROPERTIES FROM AIRBORNE IMAGING SPECTROSCOPY DATA

    Directory of Open Access Journals (Sweden)

    L. Homolová

    2016-06-01

    Full Text Available In this study we evaluated various spectral inputs for retrieval of forest chlorophyll content (Cab and leaf area index (LAI from high spectral and spatial resolution airborne imaging spectroscopy data collected for two forest study sites in the Czech Republic (beech forest at Štítná nad Vláří and spruce forest at Bílý Kříž. The retrieval algorithm was based on a machine learning method – support vector regression (SVR. Performance of the four spectral inputs used to train SVR was evaluated: a all available hyperspectral bands, b continuum removal (CR 645 – 710 nm, c CR 705 – 780 nm, and d CR 680 – 800 nm. Spectral inputs and corresponding SVR models were first assessed at the level of spectral databases simulated by combined leaf-canopy radiative transfer models PROSPECT and DART. At this stage, SVR models using all spectral inputs provided good performance (RMSE for Cab −2 and for LAI < 1.5, with consistently better performance for beech over spruce site. Since application of trained SVRs on airborne hyperspectral images of the spruce site produced unacceptably overestimated values, only the beech site results were analysed. The best performance for the Cab estimation was found for CR bands in range of 645 – 710 nm, whereas CR bands in range of 680 – 800 nm were the most suitable for LAI retrieval. The CR transformation reduced the across-track bidirectional reflectance effect present in airborne images due to large sensor field of view.

  5. Assessment of relevant hepatic steatosis in obese adolescents by rapid fat-selective GRE imaging with spatial-spectral excitation: a quantitative comparison with spectroscopic findings

    Energy Technology Data Exchange (ETDEWEB)

    Springer, Fabian; Schick, Fritz [University Hospital Tuebingen, Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); University Hospital Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Ehehalt, Stefan; Binder, Gerhard [University Children' s Hospital Tuebingen, Paediatric Endocrinology and Diabetes, Tuebingen (Germany); Sommer, Julia; Ballweg, Verena; Machann, Juergen [University Hospital Tuebingen, Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany); Claussen, Claus D. [University Hospital Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2011-04-15

    To test the feasibility of fat-selective GRE imaging using a spectral-spatial excitation technique for determination of intrahepatic lipid content (IHL) in obese adolescents. Fat-selective MR imaging (1.5 T) was applied to record a single axial slice through a representative liver region within a single breath-hold. The sequence uses six equidistant slice-selective excitation pulses with binomial amplitude ratios to achieve high selectivity for lipid signals after appropriate shimming. IHL{sub MRI} content was quantified using signal intensity of adjacent subcutaneous adipose tissue. As the gold standard for IHL quantification, single-voxel stimulated echo magnetic resonance spectroscopy (MRS) was applied. IHL{sub MRS} was quantified using the water peak as a reference. Forty-five MR examinations could be performed, and IHL{sub MRS} content ranged from 0.7% to 19.1%. Results from MRS and fat-selective imaging correlated well with Spearman coefficients between r = 0.78 and r = 0.86. There were no relevant regional differences in IHL within the liver parenchyma (p > 0.6359). Fat-selective imaging was able to reliably identify patients with IHL content above 5% with positive/negative likelihood ratio of 11.8 and 0.05, respectively. Fat-selective MR imaging provides both a reliable and a convenient method of rapidly quantifying IHL content in obese adolescents. (orig.)

  6. Spectral methods. Fundamentals in single domains

    International Nuclear Information System (INIS)

    Canuto, C.

    2006-01-01

    Since the publication of ''Spectral Methods in Fluid Dynamics'' 1988, spectral methods have become firmly established as a mainstream tool for scientific and engineering computation. The authors of that book have incorporated into this new edition the many improvements in the algorithms and the theory of spectral methods that have been made since then. This latest book retains the tight integration between the theoretical and practical aspects of spectral methods, and the chapters are enhanced with material on the Galerkin with numerical integration version of spectral methods. The discussion of direct and iterative solution methods is also greatly expanded. (orig.)

  7. Vowel Inherent Spectral Change

    CERN Document Server

    Assmann, Peter

    2013-01-01

    It has been traditional in phonetic research to characterize monophthongs using a set of static formant frequencies, i.e., formant frequencies taken from a single time-point in the vowel or averaged over the time-course of the vowel. However, over the last twenty years a growing body of research has demonstrated that, at least for a number of dialects of North American English, vowels which are traditionally described as monophthongs often have substantial spectral change. Vowel Inherent Spectral Change has been observed in speakers’ productions, and has also been found to have a substantial effect on listeners’ perception. In terms of acoustics, the traditional categorical distinction between monophthongs and diphthongs can be replaced by a gradient description of dynamic spectral patterns. This book includes chapters addressing various aspects of vowel inherent spectral change (VISC), including theoretical and experimental studies of the perceptually relevant aspects of VISC, the relationship between ar...

  8. Thin film and multilayer optics for XUV spectral domain (1 nm to 60 nm)

    International Nuclear Information System (INIS)

    Delmotte, Franck

    2010-02-01

    The XUV spectral domain (1-60 nm wavelength range) has experienced rapid growth in recent years. On one side, the sources (synchrotron radiation, harmonic generation, x-ray laser, free-electron laser...) require ever more efficient optics, on the other hand, applications (diagnostics of hot plasma, solar physics, x-ray microscopy, EUV lithography, x-ray analysis...) provide new constraints on the design of multilayer stacks. The multilayer mirrors are the only way to achieve efficient optics operating at non-grazing incidence angles in this spectral range. Our work within the team XUV Optics at Laboratoire Charles Fabry de l'Institut d'Optique focuses on the study of materials in thin layers correlated to the study of optical properties of multilayers. The objective is to achieve new multilayer components previously unavailable in the XUV domain, through a better understanding of physical phenomena in these nano-layer stacks. We show through several examples of how we have managed both to improve the performance of multilayer mirrors in a broad spectral range, and secondly, to develop new optical functions: beam splitters, broadband mirrors, dual-band mirrors or phase compensation mirrors. (author)

  9. Kernel principal component analysis residual diagnosis (KPCARD): An automated method for cosmic ray artifact removal in Raman spectra

    International Nuclear Information System (INIS)

    Li, Boyan; Calvet, Amandine; Casamayou-Boucau, Yannick; Ryder, Alan G.

    2016-01-01

    A new, fully automated, rapid method, referred to as kernel principal component analysis residual diagnosis (KPCARD), is proposed for removing cosmic ray artifacts (CRAs) in Raman spectra, and in particular for large Raman imaging datasets. KPCARD identifies CRAs via a statistical analysis of the residuals obtained at each wavenumber in the spectra. The method utilizes the stochastic nature of CRAs; therefore, the most significant components in principal component analysis (PCA) of large numbers of Raman spectra should not contain any CRAs. The process worked by first implementing kernel PCA (kPCA) on all the Raman mapping data and second accurately estimating the inter- and intra-spectrum noise to generate two threshold values. CRA identification was then achieved by using the threshold values to evaluate the residuals for each spectrum and assess if a CRA was present. CRA correction was achieved by spectral replacement where, the nearest neighbor (NN) spectrum, most spectroscopically similar to the CRA contaminated spectrum and principal components (PCs) obtained by kPCA were both used to generate a robust, best curve fit to the CRA contaminated spectrum. This best fit spectrum then replaced the CRA contaminated spectrum in the dataset. KPCARD efficacy was demonstrated by using simulated data and real Raman spectra collected from solid-state materials. The results showed that KPCARD was fast ( 1 million) Raman datasets. - Highlights: • New rapid, automatable method for cosmic ray artifact correction of Raman spectra. • Uses combination of kernel PCA and noise estimation for artifact identification. • Implements a best fit spectrum replacement correction approach.

  10. Spectrally accurate contour dynamics

    International Nuclear Information System (INIS)

    Van Buskirk, R.D.; Marcus, P.S.

    1994-01-01

    We present an exponentially accurate boundary integral method for calculation the equilibria and dynamics of piece-wise constant distributions of potential vorticity. The method represents contours of potential vorticity as a spectral sum and solves the Biot-Savart equation for the velocity by spectrally evaluating a desingularized contour integral. We use the technique in both an initial-value code and a newton continuation method. Our methods are tested by comparing the numerical solutions with known analytic results, and it is shown that for the same amount of computational work our spectral methods are more accurate than other contour dynamics methods currently in use

  11. Removal of iron and manganese from groundwater: a study of using potassium permanganate and sedimentation

    Directory of Open Access Journals (Sweden)

    Elsheikh Mohamed

    2018-01-01

    Full Text Available Experiments are done for different combinations of Fe+2 and Mn+2 concentrations. The obtained results show that Potassium Permanganate (PP gives good results in iron and manganese removal. By using PP dose near to half of the theoretically required one, it can remove up to 100 % and 90 % of iron and manganese, respectively over different tested concentrations at pH=7.0. Increasing rate of filtration influences the Mn+2 removal process obviously. Sedimentation is required when combined concentrations of iron and manganese are greater than 5.0 ppm to reduce filter rapid clogging. Using conventional treatment with adding alum, flocculation, sedimentation and filtration can remove up to 97% and 18% of iron and manganese, respectively. Using PP in addition to alum enhances manganese removal but decreases iron removal. However, using alum with increasing pH to 10 leads to 100 % and 95 % of Fe+2 and Mn+2 removal and increases filter working period.

  12. Nanomagnet-based removal of lead and digoxin from living rats

    Science.gov (United States)

    Herrmann, Inge K.; Schlegel, Andrea; Graf, Rolf; Schumacher, Christoph M.; Senn, Nico; Hasler, Melanie; Gschwind, Sabrina; Hirt, Ann-Marie; Günther, Detlef; Clavien, Pierre-Alain; Stark, Wendelin J.; Beck-Schimmer, Beatrice

    2013-08-01

    In a number of clinical conditions such as intoxication, bacteraemia or autoimmune diseases the removal of the disease-causing factor from blood would be the most direct cure. However, physicochemical characteristics of the target compounds limit the applicability of classical filtration and diffusion-based processes. In this work, we present a first in vivo magnetic blood purification rodent animal model and demonstrate its ability to rapidly clear toxins from blood circulation using two model toxins with stable plasma levels (lead (Pb2+) and digoxin). Ultra-strong functionalized metal nanomagnets are employed to eliminate the toxin from whole blood in an extracorporeal circuit. In the present experimental demonstration over 40% of the toxin (i.e. lead or digoxin) was removed within the first 10 minutes and over 75% within 40 minutes. After capturing the target substance, a magnetic trap prevents the toxin-loaded nanoparticles from entering the blood circulation. Elemental analysis and magnetic hysteresis measurements confirm full particle recovery by simple magnetic separation (residual particle concentration below 1 μg mL-1 (detection limit)). We demonstrate that magnetic separation-based blood purification offers rapid blood cleaning from noxious agents, germs or other deleterious materials with relevance to a number of clinical conditions. Based on this new approach, current blood purification technologies can be extended to efficiently remove disease-causing factors, e.g. overdosed drugs, bacteria or cancer cells without being limited by filter cut-offs or column surface saturation.

  13. Importance of copper for nitrification in biological rapid sand filters for drinking water production

    DEFF Research Database (Denmark)

    Wagner, Florian Benedikt

    When anoxic groundwater is treated to produce drinking water, ammonium is commonly removed through nitrification in rapid sand filters. Nitrification is a biological process, and is mediated by chemoautotrophic microorganisms. Ammonia oxidizing bacteria (AOB) and archaea (AOA) oxidize ammonium...... to remove ammonium to below the national drinking water quality standard of 0.05 mg NH4+/L. A better process understanding of nitrifying biofilters is needed to optimize treatment performance, remediate existing filters, and to prevent future nitrification problems. The frequent incidents of insufficient...... in the oxidation of ammonia to hydroxylamine. Thus, slow and incomplete nitrification could be caused by a lack of sufficient amounts of copper. The overall aim of this PhD project was therefore to determine whether copper supplementation could enhance nitrification in rapid sand filters with incomplete...

  14. Assessing the role of spectral and intensity cues in spectral ripple detection and discrimination in cochlear-implant users.

    Science.gov (United States)

    Anderson, Elizabeth S; Oxenham, Andrew J; Nelson, Peggy B; Nelson, David A

    2012-12-01

    Measures of spectral ripple resolution have become widely used psychophysical tools for assessing spectral resolution in cochlear-implant (CI) listeners. The objective of this study was to compare spectral ripple discrimination and detection in the same group of CI listeners. Ripple detection thresholds were measured over a range of ripple frequencies and were compared to spectral ripple discrimination thresholds previously obtained from the same CI listeners. The data showed that performance on the two measures was correlated, but that individual subjects' thresholds (at a constant spectral modulation depth) for the two tasks were not equivalent. In addition, spectral ripple detection was often found to be possible at higher rates than expected based on the available spectral cues, making it likely that temporal-envelope cues played a role at higher ripple rates. Finally, spectral ripple detection thresholds were compared to previously obtained speech-perception measures. Results confirmed earlier reports of a robust relationship between detection of widely spaced ripples and measures of speech recognition. In contrast, intensity difference limens for broadband noise did not correlate with spectral ripple detection measures, suggesting a dissociation between the ability to detect small changes in intensity across frequency and across time.

  15. Optimal spectral tracking--adapting to dynamic regime change.

    Science.gov (United States)

    Brittain, John-Stuart; Halliday, David M

    2011-01-30

    Real world data do not always obey the statistical restraints imposed upon them by sophisticated analysis techniques. In spectral analysis for instance, an ergodic process--the interchangeability of temporal for spatial averaging--is assumed for a repeat-trial design. Many evolutionary scenarios, such as learning and motor consolidation, do not conform to such linear behaviour and should be approached from a more flexible perspective. To this end we previously introduced the method of optimal spectral tracking (OST) in the study of trial-varying parameters. In this extension to our work we modify the OST routines to provide an adaptive implementation capable of reacting to dynamic transitions in the underlying system state. In so doing, we generalise our approach to characterise both slow-varying and rapid fluctuations in time-series, simultaneously providing a metric of system stability. The approach is first applied to a surrogate dataset and compared to both our original non-adaptive solution and spectrogram approaches. The adaptive OST is seen to display fast convergence and desirable statistical properties. All three approaches are then applied to a neurophysiological recording obtained during a study on anaesthetic monitoring. Local field potentials acquired from the posterior hypothalamic region of a deep brain stimulation patient undergoing anaesthesia were analysed. The characterisation of features such as response delay, time-to-peak and modulation brevity are considered. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. Intersection numbers of spectral curves

    CERN Document Server

    Eynard, B.

    2011-01-01

    We compute the symplectic invariants of an arbitrary spectral curve with only 1 branchpoint in terms of integrals of characteristic classes in the moduli space of curves. Our formula associates to any spectral curve, a characteristic class, which is determined by the laplace transform of the spectral curve. This is a hint to the key role of Laplace transform in mirror symmetry. When the spectral curve is y=\\sqrt{x}, the formula gives Kontsevich--Witten intersection numbers, when the spectral curve is chosen to be the Lambert function \\exp{x}=y\\exp{-y}, the formula gives the ELSV formula for Hurwitz numbers, and when one chooses the mirror of C^3 with framing f, i.e. \\exp{-x}=\\exp{-yf}(1-\\exp{-y}), the formula gives the Marino-Vafa formula, i.e. the generating function of Gromov-Witten invariants of C^3. In some sense this formula generalizes ELSV, Marino-Vafa formula, and Mumford formula.

  17. Rapid determination of oxygen saturation and vascularity for cancer detection.

    Directory of Open Access Journals (Sweden)

    Fangyao Hu

    Full Text Available A rapid heuristic ratiometric analysis for estimating tissue hemoglobin concentration and oxygen saturation from measured tissue diffuse reflectance spectra is presented. The analysis was validated in tissue-mimicking phantoms and applied to clinical measurements in head and neck, cervical and breast tissues. The analysis works in two steps. First, a linear equation that translates the ratio of the diffuse reflectance at 584 nm and 545 nm to estimate the tissue hemoglobin concentration using a Monte Carlo-based lookup table was developed. This equation is independent of tissue scattering and oxygen saturation. Second, the oxygen saturation was estimated using non-linear logistic equations that translate the ratio of the diffuse reflectance spectra at 539 nm to 545 nm into the tissue oxygen saturation. Correlations coefficients of 0.89 (0.86, 0.77 (0.71 and 0.69 (0.43 were obtained for the tissue hemoglobin concentration (oxygen saturation values extracted using the full spectral Monte Carlo and the ratiometric analysis, for clinical measurements in head and neck, breast and cervical tissues, respectively. The ratiometric analysis was more than 4000 times faster than the inverse Monte Carlo analysis for estimating tissue hemoglobin concentration and oxygen saturation in simulated phantom experiments. In addition, the discriminatory power of the two analyses was similar. These results show the potential of such empirical tools to rapidly estimate tissue hemoglobin in real-time spectral imaging applications.

  18. Atmospheric parameters, spectral indexes and their relation to CPV spectral performance

    Energy Technology Data Exchange (ETDEWEB)

    Núñez, Rubén, E-mail: ruben.nunez@ies-def.upm.es; Antón, Ignacio, E-mail: ruben.nunez@ies-def.upm.es; Askins, Steve, E-mail: ruben.nunez@ies-def.upm.es; Sala, Gabriel, E-mail: ruben.nunez@ies-def.upm.es [Instituto de Energía Solar - Universidad Politécnica de Madrid, Instituto de Energía Solar, ETSI Telecomunicación, Ciudad Universitaria 28040 Madrid (Spain)

    2014-09-26

    Air Mass and atmosphere components (basically aerosol (AOD) and precipitable water (PW)) define the absorption of the sunlight that arrive to Earth. Radiative models such as SMARTS or MODTRAN use these parameters to generate an equivalent spectrum. However, complex and expensive instruments (as AERONET network devices) are needed to obtain AOD and PW. On the other hand, the use of isotype cells is a convenient way to characterize spectrally a place for CPV considering that they provide the photocurrent of the different internal subcells individually. Crossing data from AERONET station and a Tri-band Spectroheliometer, a model that correlates Spectral Mismatch Ratios and atmospheric parameters is proposed. Considering the amount of stations of AERONET network, this model may be used to estimate the spectral influence on energy performance of CPV systems close to all the stations worldwide.

  19. Calibration with near-continuous spectral measurements

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Rasmussen, Michael; Madsen, Henrik

    2001-01-01

    In chemometrics traditional calibration in case of spectral measurements express a quantity of interest (e.g. a concentration) as a linear combination of the spectral measurements at a number of wavelengths. Often the spectral measurements are performed at a large number of wavelengths and in thi...... by an example in which the octane number of gasoline is related to near infrared spectral measurements. The performance is found to be much better that for the traditional calibration methods....

  20. Removal of oil films from stainless steel tubes

    Energy Technology Data Exchange (ETDEWEB)

    Yan, J.F.; Saez, A.E.; Grant, C.S. [North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemical Engineering

    1997-01-01

    The contamination of metal surfaces with oil is a widespread problem in the chemical, metalworking, and automotive industries. The main source of oil fouling comes from the process fluids in various operations. For example, in a heat exchanger, the oil contaminates the equipment surface causing a lower heat-transfer efficiency. The fouled equipment leads to increased costs due to added heat-transfer area, maintenance, energy, and production losses caused by unit downtime. The removal of oil films from the inner surface of a stainless steel tube cell using aqueous cleaning solutions was studied. The two oils used in the cleaning experiments, Sunquench 1042 and heavy mineral oil, contained P{sup 32} labeled tributyl phosphate (TBP) as a radioactive tracer. The {beta}{sup {minus}} particles emitted from the radioactive TBP were detected by a CaF{sub 2} scintillator and used as a measure of the amount of oil remaining in the tube cell. Cleaning experiments performed at different flow rates, surface treatment, and surfactant concentrations indicated that initially the oil films were removed rapidly. At the end of the experiments, the oil removal rate reduced significantly, eventually becoming negligible. The stainless steel morphology affected oil removal significantly, and the rougher tube tended to retard the oil removal. The rate and extent of the decontamination were significantly increased in the presence of sodium dodecyl sulfate, a nonionic surfactant. Experimental data were compared to a hydrodynamic model based on the removal of a liquid contaminant from a solid surface by an immiscible fluid. The model deviated from the experimental data due to the presence of instabilities at the oil-water interface.

  1. Stratification of nitrification activity in rapid sand filters for drinking water treatment

    DEFF Research Database (Denmark)

    Tatari, Karolina; Smets, Barth F.; Musovic, Sanin

    2013-01-01

    Rapid sand filters used in groundwater treatment remove ammonium, iron and manganese from the water. Ammonium is removed biologically by nitrifying microorganisms attached on the sand surface. Nitrification kinetics and activity is strongly affected by filter design and operation, which are the key...... and maximum nitrification capacity are derived and used to quantify nitrification activity. Nitrification activity was concentrated at the top 10 cm of filter depth, and maximum nitrification capacity was 7 g NH4+-N/ m3 sand/h compared with 0.8-0.4 g NH4+-N/ m3 sand/h in the middle and bottom layers. A water...... of this study is to investigate nitrification activity in a rapid sand filter, with focus on its homogeneity and how it relates to filter performance. Two groundwater treatment plants in Denmark were selected for the experimental investigations. Plant 1 operates a single line of pre and after filters and has...

  2. Response of green reflectance continuum removal index to the xanthophyll de-epoxidation cycle in Norway spruce needles

    Czech Academy of Sciences Publication Activity Database

    Kováč, Daniel; Malenovský, Z.; Urban, O.; Špunda, Vladimír; Kalina, J.; Ač, Alexander; Kaplan, Věroslav; Hanuš, Jan

    2013-01-01

    Roč. 64, č. 7 (2013), s. 1-11 ISSN 0022-0957 R&D Projects: GA MŠk LD12042; GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk(CZ) LM2010007 Institutional support: RVO:67179843 Keywords : chlorophyll to carotenoid ratio * continuum removal * excessive irradiance * excessive irradiance * spectral index * xanthophyll cycle pigments Subject RIV: EH - Ecology, Behaviour Impact factor: 5.794, year: 2013

  3. Identification of spectral units on Phoebe

    Science.gov (United States)

    Coradini, A.; Tosi, F.; Gavrishin, A.I.; Capaccioni, F.; Cerroni, P.; Filacchione, G.; Adriani, A.; Brown, R.H.; Bellucci, G.; Formisano, V.; D'Aversa, E.; Lunine, J.I.; Baines, K.H.; Bibring, J.-P.; Buratti, B.J.; Clark, R.N.; Cruikshank, D.P.; Combes, M.; Drossart, P.; Jaumann, R.; Langevin, Y.; Matson, D.L.; McCord, T.B.; Mennella, V.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Sotin, Christophe; Hedman, M.M.; Hansen, G.B.; Hibbitts, C.A.; Showalter, M.; Griffith, C.; Strazzulla, G.

    2008-01-01

    We apply a multivariate statistical method to the Phoebe spectra collected by the VIMS experiment onboard the Cassini spacecraft during the flyby of June 2004. The G-mode clustering method, which permits identification of the most important features in a spectrum, is used on a small subset of data, characterized by medium and high spatial resolution, to perform a raw spectral classification of the surface of Phoebe. The combination of statistics and comparative analysis of the different areas using both the VIMS and ISS data is explored in order to highlight possible correlations with the surface geology. In general, the results by Clark et al. [Clark, R.N., Brown, R.H., Jaumann, R., Cruikshank, D.P., Nelson, R.M., Buratti, B.J., McCord, T.B., Lunine, J., Hoefen, T., Curchin, J.M., Hansen, G., Hibbitts, K., Matz, K.-D., Baines, K.H., Bellucci, G., Bibring, J.-P., Capaccioni, F., Cerroni, P., Coradini, A., Formisano, V., Langevin, Y., Matson, D.L., Mennella, V., Nicholson, P.D., Sicardy, B., Sotin, C., 2005. Nature 435, 66-69] are confirmed; but we also identify new signatures not reported before, such as the aliphatic CH stretch at 3.53 ??m and the ???4.4 ??m feature possibly related to cyanide compounds. On the basis of the band strengths computed for several absorption features and for the homogeneous spectral types isolated by the G-mode, a strong correlation of CO2 and aromatic hydrocarbons with exposed water ice, where the uniform layer covering Phoebe has been removed, is established. On the other hand, an anti-correlation of cyanide compounds with CO2 is suggested at a medium resolution scale. ?? 2007 Elsevier Inc. All rights reserved.

  4. Calibrating spectral images using penalized likelihood

    NARCIS (Netherlands)

    Heijden, van der G.W.A.M.; Glasbey, C.

    2003-01-01

    A new method is presented for automatic correction of distortions and for spectral calibration (which band corresponds to which wavelength) of spectral images recorded by means of a spectrograph. The method consists of recording a bar-like pattern with an illumination source with spectral bands

  5. Spectral Learning for Supervised Topic Models.

    Science.gov (United States)

    Ren, Yong; Wang, Yining; Zhu, Jun

    2018-03-01

    Supervised topic models simultaneously model the latent topic structure of large collections of documents and a response variable associated with each document. Existing inference methods are based on variational approximation or Monte Carlo sampling, which often suffers from the local minimum defect. Spectral methods have been applied to learn unsupervised topic models, such as latent Dirichlet allocation (LDA), with provable guarantees. This paper investigates the possibility of applying spectral methods to recover the parameters of supervised LDA (sLDA). We first present a two-stage spectral method, which recovers the parameters of LDA followed by a power update method to recover the regression model parameters. Then, we further present a single-phase spectral algorithm to jointly recover the topic distribution matrix as well as the regression weights. Our spectral algorithms are provably correct and computationally efficient. We prove a sample complexity bound for each algorithm and subsequently derive a sufficient condition for the identifiability of sLDA. Thorough experiments on synthetic and real-world datasets verify the theory and demonstrate the practical effectiveness of the spectral algorithms. In fact, our results on a large-scale review rating dataset demonstrate that our single-phase spectral algorithm alone gets comparable or even better performance than state-of-the-art methods, while previous work on spectral methods has rarely reported such promising performance.

  6. In situ, rapid, and temporally resolved measurements of cellulase adsorption onto lignocellulosic substrates by UV-vis spectrophotometry

    Science.gov (United States)

    Hao Liu; J. Y. Zhu; X. S. Chai

    2011-01-01

    This study demonstrated two in situ UV-vis spectrophotometric methods for rapid and temporally resolved measurements of cellulase adsorption onto cellulosic and lignocellulosic substrates during enzymatic hydrolysis. The cellulase protein absorption peak at 280 nm was used for quantification. The spectral interferences from light scattering by small fibers (fines) and...

  7. Metallicity and the spectral energy distribution and spectral types of dwarf O-stars

    NARCIS (Netherlands)

    Mokiem, MR; Martin-Hernandez, NL; Lenorzer, A; de Koter, A; Tielens, AGGA

    We present a systematic study of the effect of metallicity on the stellar spectral energy distribution (SED) of 0 main sequence (dwarf) stars, focussing on the hydrogen and helium ionizing continua, and on the optical and near-IR lines used for spectral classification. The spectra are based on

  8. Metallicity and the spectral energy distribution and spectral types of dwarf O-stars

    NARCIS (Netherlands)

    Mokiem, M.R.; Martín-Hernández, N.L.; Lenorzer, A.; de Koter, A.; Tielens, A.G.G.M.

    2004-01-01

    We present a systematic study of the effect of metallicity on the stellar spectral energy distribution (SED) of O main sequence (dwarf) stars, focussing on the hydrogen and helium ionizing continua, and on the optical and near-IR lines used for spectral classification. The spectra are based on

  9. Relationships between spectral and bird species rarefaction curves in a brutian pine forest ecosystem

    OpenAIRE

    Özdemir, İbrahim; Mert, Ahmet; Özkan, Ulaş Yunus; Aksan, Şengül; Ünal, Yasin

    2017-01-01

    This study aimed at determining the relations betweenspectral and bird species rarefaction curves in a brutian pine forest ecosystemlocated in the Fethiye region, Turkey. Bird species were counted by fieldworkin 40 sample plots with 0.81 ha (90 x 90 m). The NDVITOA values of pixelsbelonging to each plot (pixel numbers are 36, 81 and 324 for Aster, SPOT andRapidEye, respectively) were calculated. Spectral and bird species rarefactioncurves were formed by means of EstimatesS software. The relat...

  10. The dynamics of femtosecond pulsed laser removal of 20 nm Ni films from an interface

    Energy Technology Data Exchange (ETDEWEB)

    Schrider, Keegan J.; Yalisove, Steven M. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Torralva, Ben [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2015-09-21

    The dynamics of femtosecond laser removal of 20 nm Ni films on glass substrates was studied using time-resolved pump-probe microscopy. 20 nm thin films exhibit removal at two distinct threshold fluences, removal of the top 7 nm of Ni above 0.14 J/cm{sup 2}, and removal of the entire 20 nm film above 0.36 J/cm{sup 2}. Previous work shows the top 7 nm is removed through liquid spallation, after irradiation the Ni melts and rapidly expands leading to tensile stress and cavitation within the Ni film. This work shows that above 0.36 J/cm{sup 2} the 20 nm film is removed in two distinct layers, 7 nm and 13 nm thick. The top 7 nm layer reaches a speed 500% faster than the bottom 13 nm layer at the same absorbed fluence, 500–2000 m/s and 300–700 m/s in the fluence ranges studied. Significantly different velocities for the top 7 nm layer and bottom 13 nm layer indicate removal from an interface occurs by a different physical mechanism. The method of measuring film displacement from the development of Newton's rings was refined so it could be shown that the 13 nm layer separates from the substrate within 70 ps and accelerates to its final velocity within several hundred picoseconds. We propose that removal of the bottom 13 nm is consistent with heterogeneous nucleation and growth of vapor at the Ni-glass interface, but that the rapid separation and acceleration of the 13 nm layer from the Ni-glass interface requires consideration of exotic phases of Ni after excitation.

  11. Rapid Sediment Accumulation Results in High Methane Effluxes from Coastal Sediments.

    Directory of Open Access Journals (Sweden)

    Matthias Egger

    Full Text Available Globally, the methane (CH4 efflux from the ocean to the atmosphere is small, despite high rates of CH4 production in continental shelf and slope environments. This low efflux results from the biological removal of CH4 through anaerobic oxidation with sulfate in marine sediments. In some settings, however, pore water CH4 is found throughout the sulfate-bearing zone, indicating an apparently inefficient oxidation barrier for CH4. Here we demonstrate that rapid sediment accumulation can explain this limited capacity for CH4 removal in coastal sediments. In a saline coastal reservoir (Lake Grevelingen, The Netherlands, we observed high diffusive CH4 effluxes from the sediment into the overlying water column (0.2-0.8 mol m-2 yr-1 during multiple years. Linear pore water CH4 profiles and the absence of an isotopic enrichment commonly associated with CH4 oxidation in a zone with high rates of sulfate reduction (50-170 nmol cm-3 d-1 both suggest that CH4 is bypassing the zone of sulfate reduction. We propose that the rapid sediment accumulation at this site (~ 13 cm yr-1 reduces the residence time of the CH4 oxidizing microorganisms in the sulfate/methane transition zone (< 5 years, thus making it difficult for these slow growing methanotrophic communities to build-up sufficient biomass to efficiently remove pore water CH4. In addition, our results indicate that the high input of organic matter (~ 91 mol C m-2 yr-1 allows for the co-occurrence of different dissimilatory respiration processes, such as (acetotrophic methanogenesis and sulfate reduction in the surface sediments by providing abundant substrate. We conclude that anthropogenic eutrophication and rapid sediment accumulation likely increase the release of CH4 from coastal sediments.

  12. Anaerobic treatment of cellulose bleach plant wastewater: chlorinated organics and genotoxicity removal

    Directory of Open Access Journals (Sweden)

    T. R. Chaparro

    2011-12-01

    Full Text Available This study assessed the removal efficiency of organic matter and how it relates to the decrease of toxic and mutagenic effects when an anaerobic reactor is used to treat the bleaching effluent from two kraft pulp mills. Parameters such as COD (chemical oxygen demand, DOC (dissolved organic carbon, AOX (adsorbable organic halogen, ASL (acid soluble lignin, color, chlorides, total phenols and absorbance values in the UV-VIS spectral region were measured. The acute and chronic toxicity and genetic toxicity assessments were performed with Daphnia similis, Ceriodaphnia sp. and Allium cepa L, respectively. The removal efficiency of organic matter measured as COD, ranged from 45% to 55%, while AOX removal ranged from 40% to 45%. The acute toxic and chronic effects, as well as the cytotoxic, genotoxic and mutagenic effects, decrease as the biodegradable fraction of the organics is removed. These results, together with the organic load measurement of the effluents of the anaerobic treatment, indicate that these effluents are recalcitrant but not toxic. As expected, color increased when the anaerobic treatment was applied. However, the colored compounds are of microbial origin and do not cause an increase in genotoxic effects. To discharge the wastewater, it is necessary to apply a physico-chemical or aerobic biological post-treatment to the effluents of the anaerobic reactor.

  13. Toward an optimal solver for time-spectral fluid-dynamic and aeroelastic solutions on unstructured meshes

    Science.gov (United States)

    Mundis, Nathan L.; Mavriplis, Dimitri J.

    2017-09-01

    The time-spectral method applied to the Euler and coupled aeroelastic equations theoretically offers significant computational savings for purely periodic problems when compared to standard time-implicit methods. However, attaining superior efficiency with time-spectral methods over traditional time-implicit methods hinges on the ability rapidly to solve the large non-linear system resulting from time-spectral discretizations which become larger and stiffer as more time instances are employed or the period of the flow becomes especially short (i.e. the maximum resolvable wave-number increases). In order to increase the efficiency of these solvers, and to improve robustness, particularly for large numbers of time instances, the Generalized Minimal Residual Method (GMRES) is used to solve the implicit linear system over all coupled time instances. The use of GMRES as the linear solver makes time-spectral methods more robust, allows them to be applied to a far greater subset of time-accurate problems, including those with a broad range of harmonic content, and vastly improves the efficiency of time-spectral methods. In previous work, a wave-number independent preconditioner that mitigates the increased stiffness of the time-spectral method when applied to problems with large resolvable wave numbers has been developed. This preconditioner, however, directly inverts a large matrix whose size increases in proportion to the number of time instances. As a result, the computational time of this method scales as the cube of the number of time instances. In the present work, this preconditioner has been reworked to take advantage of an approximate-factorization approach that effectively decouples the spatial and temporal systems. Once decoupled, the time-spectral matrix can be inverted in frequency space, where it has entries only on the main diagonal and therefore can be inverted quite efficiently. This new GMRES/preconditioner combination is shown to be over an order of

  14. Spectral filtering for plant production

    Energy Technology Data Exchange (ETDEWEB)

    Young, R.E.; McMahon, M.J.; Rajapakse, N.C.; Becoteau, D.R.

    1994-12-31

    Research to date suggests that spectral filtering can be an effective alternative to chemical growth regulators for altering plant development. If properly implemented, it can be nonchemical and environmentally friendly. The aqueous CuSO{sub 4}, and CuCl{sub 2} solutions in channelled plastic panels have been shown to be effective filters, but they can be highly toxic if the solutions contact plants. Some studies suggest that spectral filtration limited to short EOD intervals can also alter plant development. Future research should be directed toward confirmation of the influence of spectral filters and exposure times on a broader range of plant species and cultivars. Efforts should also be made to identify non-noxious alternatives to aqueous copper solutions and/or to incorporate these chemicals permanently into plastic films and panels that can be used in greenhouse construction. It would also be informative to study the impacts of spectral filters on insect and microbal populations in plant growth facilities. The economic impacts of spectral filtering techniques should be assessed for each delivery methodology.

  15. A method for removing adobe-type manure from hides using an oxidizing agent

    Science.gov (United States)

    Adobe-type (hardened) manure attached to bovine hair is a major source of meat contamination, hide quality deterioration, and devalued leather products. Therefore, it is important to develop cleaning solutions that can rapidly remove adobe-type manure to improve the quality of hides delivered to tan...

  16. Removal of detergents from SDS-inactivated dextransucrase

    International Nuclear Information System (INIS)

    Husman, D.W.; Mayer, R.M.

    1986-01-01

    Dextransucrase, which is rapidly inactivated by SDS, can be reactivated upon the addition of Triton X-100. Purification of the enzyme, in good yield and homogeneity, has been achieved by chromatography in the presence of SDS. The purified enzyme can be reactivated with Triton, but has large amounts of detergents. It was important to develop procedures for their removal. Density gradient centrifugation of SDS-inactivated or Triton-reactivated enzyme, treatment with Extracti-Gel D (Pierce) or chromatography on hydroxyl apatite (HA), have been examined for their effectiveness in providing detergent-free enzyme in good yield. Ultracentrifugation of SDS-inactivated protein provided limited recovery of active enzyme, but suggested that reactivation could be achieved by the simple removal of the detergent. While similar behavior was observed when the enzyme was eluted from Extracti-Gel, it was also shown that the limited recovery was a result of irreversible inactivation of the enzyme. Recovery could be improved if the enzyme was collected in solutions containing Triton, which has been reported to be a stabilizer. Chromatography of SDS-inactivated enzyme on HA also yielded active enzyme. Good recovery was obtained when Triton-reactivated enzyme was employed in these studies. The degree of detergent removal was determined by utilizing radiolabelled SDS and Triton X-100

  17. Rapid polyclonal desensitization with antibodies to IgE and FcεRIα.

    Science.gov (United States)

    Khodoun, Marat V; Kucuk, Zeynep Yesim; Strait, Richard T; Krishnamurthy, Durga; Janek, Kevin; Lewkowich, Ian; Morris, Suzanne C; Finkelman, Fred D

    2013-06-01

    Rapid desensitization, a procedure in which persons allergic to an antigen are treated at short intervals with increasing doses of that antigen until they tolerate a large dose, is an effective, but risky, way to induce temporary tolerance. We wanted to determine whether this approach can be adapted to suppress all IgE-mediated allergies in mice by injecting serially increasing doses of monoclonal antibodies (mAbs) to IgE or FcεRIα. Active and passive models of antigen- and anti-IgE mAb-induced IgE-mediated anaphylaxis were used. Mice were desensitized with serially increasing doses of anti-IgE mAb, anti-FcεRIα mAb, or antigen. Development of shock (hypothermia), histamine and mast cell protease release, cytokine secretion, calcium flux, and changes in cell number and FcεRI and IgE expression were evaluated. Rapid desensitization with anti-IgE mAb suppressed IgE-mediated immediate hypersensitivity; however, some mice developed mild anaphylaxis during desensitization. Rapid desensitization with anti-FcεRIα mAb that only binds FcεRI that is not occupied by IgE suppressed both active and passive IgE-mediated anaphylaxis without inducing disease. It quickly, but temporarily, suppressed IgE-mediated anaphylaxis by decreasing mast cell signaling through FcεRI, then slowly induced longer lasting mast cell unresponsiveness by removing membrane FcεRI. Rapid desensitization with anti-FcεRIα mAb was safer and longer lasting than rapid desensitization with antigen. A rapid desensitization approach with anti-FcεRIα mAb safely desensitizes mice to IgE-mediated anaphylaxis by inducing mast cell anergy and later removing all mast cell IgE. Rapid desensitization with an anti-human FcεRIα mAb may be able to prevent human IgE-mediated anaphylaxis. Copyright © 2013 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

  18. Removing radioactive noble gases from nuclear process off-gases

    International Nuclear Information System (INIS)

    Lofredo, A.

    1977-01-01

    A system is claimed for separating, concentrating and storing radioactive krypton and xenon in the off-gases from a boiling water reactor, wherein adsorption and cryogenic distillation are both efficiently used for rapid and positive separation and removal of the radioactive noble gases, and for limiting such gases in circulation in the system to low inventory at all times, and wherein the system is self-regulating to eliminate operator options or attention

  19. Wavelength selection for portable noninvasive blood component measurement system based on spectral difference coefficient and dynamic spectrum

    Science.gov (United States)

    Feng, Ximeng; Li, Gang; Yu, Haixia; Wang, Shaohui; Yi, Xiaoqing; Lin, Ling

    2018-03-01

    Noninvasive blood component analysis by spectroscopy has been a hotspot in biomedical engineering in recent years. Dynamic spectrum provides an excellent idea for noninvasive blood component measurement, but studies have been limited to the application of broadband light sources and high-resolution spectroscopy instruments. In order to remove redundant information, a more effective wavelength selection method has been presented in this paper. In contrast to many common wavelength selection methods, this method is based on sensing mechanism which has a clear mechanism and can effectively avoid the noise from acquisition system. The spectral difference coefficient was theoretically proved to have a guiding significance for wavelength selection. After theoretical analysis, the multi-band spectral difference coefficient-wavelength selection method combining with the dynamic spectrum was proposed. An experimental analysis based on clinical trial data from 200 volunteers has been conducted to illustrate the effectiveness of this method. The extreme learning machine was used to develop the calibration models between the dynamic spectrum data and hemoglobin concentration. The experiment result shows that the prediction precision of hemoglobin concentration using multi-band spectral difference coefficient-wavelength selection method is higher compared with other methods.

  20. On Longitudinal Spectral Coherence

    DEFF Research Database (Denmark)

    Kristensen, Leif

    1979-01-01

    It is demonstrated that the longitudinal spectral coherence differs significantly from the transversal spectral coherence in its dependence on displacement and frequency. An expression for the longitudinal coherence is derived and it is shown how the scale of turbulence, the displacement between ...... observation sites and the turbulence intensity influence the results. The limitations of the theory are discussed....

  1. Phosphate limitation in biological rapid sand filters used to remove ammonium from drinking water

    DEFF Research Database (Denmark)

    Lee, Carson Odell; Albrechtsen, Hans-Jørgen; Smets, Barth F.

    2013-01-01

    Removing ammonium from drinking water is important for maintaining biological stability in distribution systems. This is especially important in regions that do not use disinfectants in the treatment process or keep a disinfectant residual in the distribution system. Problems with nitrification c...... a pilot scale sand column which initial analysis confirmed performed similarly to the full scale filters. Long term increased ammonium loads were applied to the pilot filter both with and without phosphate addition. Phosphate was added at a concentration of 0.5 mg PO4-P/L to ensure...

  2. Preparation of core-shell structured CaCO3 microspheres as rapid and recyclable adsorbent for anionic dyes

    Science.gov (United States)

    Zhao, Mengen; Chen, Zhenhua; Lv, Xinyan; Zhou, Kang; Zhang, Jie; Tian, Xiaohan; Ren, Xiuli; Mei, Xifan

    2017-09-01

    Core-shell structured CaCO3 microspheres (MSs) were prepared by a facile, one-pot method at room temperature. The adsorbent dosage and adsorption time of the obtained CaCO3 MSs were investigated. The results suggest that these CaCO3 MSs can rapidly and efficiently remove 99-100% of anionic dyes within the first 2 min. The obtained CaCO3 MSs have a high Brunauer-Emmett-Teller surface area (211.77 m2 g-1). In addition, the maximum adsorption capacity of the obtained CaCO3 MSs towards Congo red was 99.6 mg g-1. We also found that the core-shell structured CaCO3 MSs have a high recycling capability for removing dyes from water. Our results demonstrate that the prepared core-shell structured CaCO3 MSs can be used as an ideal, rapid, efficient and recyclable adsorbent to remove dyes from aqueous solution.

  3. Speech recognition from spectral dynamics

    Indian Academy of Sciences (India)

    Carrier nature of speech; modulation spectrum; spectral dynamics ... the relationships between phonetic values of sounds and their short-term spectral envelopes .... the number of free parameters that need to be estimated from training data.

  4. Removal of mineral oil and wastewater pollutants using hard coal

    Directory of Open Access Journals (Sweden)

    BRANISLAV R. SIMONOVIĆ

    2009-05-01

    Full Text Available This study investigates the use of hard coal as an adsorbent for removal of mineral oil from wastewater. In order to determine the efficiency of hard coal as an adsorbent of mineral oil, process parameters such as sorption capacity (in static and dynamic conditions, temperature, pH, contact time, flow rate, and chemical pretreatment were evaluated in a series of batch and continuous flow experiments. There were significant differences in the mineral oil removal for various pH values examined. The adsorption of mineral oil increased as pH values diverged from 7 (neutral. At lower temperatures, the adsorption was notably higher. The wastewater flow rate was adjusted to achieve optimal water purification. Equilibrium was reached after 10 h in static conditions. At that time, more than 99% of mineral oil had been removed. At the beginning of the filtering process, the adsorption rate increased rapidly, only to show a minor decrease afterwards. Equilibrium data were fitted to Freundlich models to determine the water-hard coal partitioning coefficient. Physical adsorption caused by properties of the compounds was the predominant mechanism in the removal process.

  5. Rapid extraction and assay of uranium from environmental surface samples

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Christopher A.; Chouyyok, Wilaiwan; Speakman, Robert J.; Olsen, Khris B.; Addleman, Raymond Shane

    2017-10-01

    Extraction methods enabling faster removal and concentration of uranium compounds for improved trace and low-level assay are demonstrated for standard surface sampling material in support of nuclear safeguards efforts, health monitoring, and other nuclear analysis applications. A key problem with the existing surface sampling swipes is the requirement for complete digestion of sample and sampling matrix. This is a time-consuming and labour-intensive process that limits laboratory throughput, elevates costs, and increases background levels. Various extraction methods are explored for their potential to quickly and efficiently remove different chemical forms of uranium from standard surface sampling material. A combination of carbonate and peroxide solutions is shown to give the most rapid and complete form of uranyl compound extraction and dissolution. This rapid extraction process is demonstrated to be compatible with standard inductive coupled plasma mass spectrometry methods for uranium isotopic assay as well as screening techniques such as x-ray fluorescence. The general approach described has application beyond uranium to other analytes of nuclear forensic interest (e.g., rare earth elements and plutonium) as well as heavy metals for environmental and industrial hygiene monitoring.

  6. Meson spectral functions at finite temperature

    International Nuclear Information System (INIS)

    Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S.

    2001-10-01

    The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T c . The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64) 3 x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature. (orig.)

  7. Meson spectral functions at finite temperature

    International Nuclear Information System (INIS)

    Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S.

    2002-01-01

    The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T c . The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64) 3 x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature

  8. Meson spectral functions at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S

    2002-03-01

    The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T{sub c}. The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64){sup 3} x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature.

  9. Meson spectral functions at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S. [Bielefeld Univ. (Germany). Fakultaet fuer Physik

    2001-10-01

    The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T{sub c}. The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64){sup 3} x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature. (orig.)

  10. The development of a modified spectral ripple test.

    Science.gov (United States)

    Aronoff, Justin M; Landsberger, David M

    2013-08-01

    Poor spectral resolution can be a limiting factor for hearing impaired listeners, particularly for complex listening tasks such as speech understanding in noise. Spectral ripple tests are commonly used to measure spectral resolution, but these tests contain a number of potential confounds that can make interpretation of the results difficult. To measure spectral resolution while avoiding those confounds, a modified spectral ripple test with dynamically changing ripples was created, referred to as the spectral-temporally modulated ripple test (SMRT). This paper describes the SMRT and provides evidence that it is sensitive to changes in spectral resolution.

  11. Comparing auditory filter bandwidths, spectral ripple modulation detection, spectral ripple discrimination, and speech recognition: Normal and impaired hearing.

    Science.gov (United States)

    Davies-Venn, Evelyn; Nelson, Peggy; Souza, Pamela

    2015-07-01

    Some listeners with hearing loss show poor speech recognition scores in spite of using amplification that optimizes audibility. Beyond audibility, studies have suggested that suprathreshold abilities such as spectral and temporal processing may explain differences in amplified speech recognition scores. A variety of different methods has been used to measure spectral processing. However, the relationship between spectral processing and speech recognition is still inconclusive. This study evaluated the relationship between spectral processing and speech recognition in listeners with normal hearing and with hearing loss. Narrowband spectral resolution was assessed using auditory filter bandwidths estimated from simultaneous notched-noise masking. Broadband spectral processing was measured using the spectral ripple discrimination (SRD) task and the spectral ripple depth detection (SMD) task. Three different measures were used to assess unamplified and amplified speech recognition in quiet and noise. Stepwise multiple linear regression revealed that SMD at 2.0 cycles per octave (cpo) significantly predicted speech scores for amplified and unamplified speech in quiet and noise. Commonality analyses revealed that SMD at 2.0 cpo combined with SRD and equivalent rectangular bandwidth measures to explain most of the variance captured by the regression model. Results suggest that SMD and SRD may be promising clinical tools for diagnostic evaluation and predicting amplification outcomes.

  12. Comparing auditory filter bandwidths, spectral ripple modulation detection, spectral ripple discrimination, and speech recognition: Normal and impaired hearinga)

    Science.gov (United States)

    Davies-Venn, Evelyn; Nelson, Peggy; Souza, Pamela

    2015-01-01

    Some listeners with hearing loss show poor speech recognition scores in spite of using amplification that optimizes audibility. Beyond audibility, studies have suggested that suprathreshold abilities such as spectral and temporal processing may explain differences in amplified speech recognition scores. A variety of different methods has been used to measure spectral processing. However, the relationship between spectral processing and speech recognition is still inconclusive. This study evaluated the relationship between spectral processing and speech recognition in listeners with normal hearing and with hearing loss. Narrowband spectral resolution was assessed using auditory filter bandwidths estimated from simultaneous notched-noise masking. Broadband spectral processing was measured using the spectral ripple discrimination (SRD) task and the spectral ripple depth detection (SMD) task. Three different measures were used to assess unamplified and amplified speech recognition in quiet and noise. Stepwise multiple linear regression revealed that SMD at 2.0 cycles per octave (cpo) significantly predicted speech scores for amplified and unamplified speech in quiet and noise. Commonality analyses revealed that SMD at 2.0 cpo combined with SRD and equivalent rectangular bandwidth measures to explain most of the variance captured by the regression model. Results suggest that SMD and SRD may be promising clinical tools for diagnostic evaluation and predicting amplification outcomes. PMID:26233047

  13. Rapid prototyping: An innovative technique in dentistry

    Directory of Open Access Journals (Sweden)

    Shakeba Quadri

    2017-01-01

    Full Text Available Emergence of advanced digital technology has opened up new perspectives for design and production in the field of dentistry. Rapid prototyping (RP is a technique to quickly and automatically construct a three-dimensional (3D model of a part or product using 3D printers or stereolithography machines. RP has various dental applications, such as fabrication of implant surgical guides, zirconia prosthesis and molds for metal castings, maxillofacial prosthesis and frameworks for fixed and removable partial dentures, wax patterns for the dental prosthesis and complete denture. Rapid prototyping presents fascinating opportunities, but the process is difficult as it demands a high level of artistic skill, which means that the dental technicians should be able to work with the models obtained after impression to form a mirror image and achieve good esthetics. This review aims to focus on various RP methods and its application in dentistry.

  14. Rapid prototyping model for percutaneous nephrolithotomy training.

    Science.gov (United States)

    Bruyère, Franck; Leroux, Cecile; Brunereau, Laurent; Lermusiaux, Patrick

    2008-01-01

    Rapid prototyping is a technique used for creating computer images in three dimensions more efficiently than classic techniques. Percutaneous nephrolithotomy (PCNL) is a popular method to remove kidney stones; however, broader use by the urologic community has been hampered by the morbidity associated with needle puncture to gain access to the renal calix (bleeding, pneumothorax, hydrothorax, inadvertent colon injury). A training model to improve technique and understanding of renal anatomy could improve complications related to renal puncture; however, no model currently exists for resident training. We created a training model using the rapid prototyping technique based on abdominal CT images of a patient scheduled to undergo PCNL. This allowed our staff and residents to train on the model before performing the operation. This model allowed anticipation of particular difficulties inherent to the patient's anatomy. After training, the procedure proceeded without complication, and the patient was discharged at postoperative day 1 without problems. We hypothesize that rapid prototyping could be useful for resident education, allowing the creation of numerous models for research and surgical training. In addition, we anticipate that experienced urologists could find this technique helpful in preparation for difficult PCNL operations.

  15. Optimizing cloud removal from satellite remotely sensed data for monitoring vegetation dynamics in humid tropical climate

    International Nuclear Information System (INIS)

    Hashim, M; Pour, A B; Onn, C H

    2014-01-01

    Remote sensing technology is an important tool to analyze vegetation dynamics, quantifying vegetation fraction of Earth's agricultural and natural vegetation. In optical remote sensing analysis removing atmospheric interferences, particularly distribution of cloud contaminations, are always a critical task in the tropical climate. This paper suggests a fast and alternative approach to remove cloud and shadow contaminations for Landsat Enhanced Thematic Mapper + (ETM + ) multi temporal datasets. Band 3 and Band 4 from all the Landsat ETM + dataset are two main spectral bands that are very crucial in this study for cloud removal technique. The Normalise difference vegetation index (NDVI) and the normalised difference soil index (NDSI) are two main derivatives derived from the datasets. Change vector analysis is used in this study to seek the vegetation dynamics. The approach developed in this study for cloud optimizing can be broadly applicable for optical remote sensing satellite data, which are seriously obscured with heavy cloud contamination in the tropical climate

  16. Spectral properties of generalized eigenparameter dependent ...

    African Journals Online (AJOL)

    Jost function, spectrum, the spectral singularities, and the properties of the principal vectors corresponding to the spectral singularities of L, if. ∞Σn=1 n(∣1 - an∣ + ∣bnl) < ∞. Mathematics Subject Classication (2010): 34L05, 34L40, 39A70, 47A10, 47A75. Key words: Discrete equations, eigenparameter, spectral analysis, ...

  17. Rapid analysis of pharmaceutical drugs using LIBS coupled with multivariate analysis.

    Science.gov (United States)

    Tiwari, P K; Awasthi, S; Kumar, R; Anand, R K; Rai, P K; Rai, A K

    2018-02-01

    Type 2 diabetes drug tablets containing voglibose having dose strengths of 0.2 and 0.3 mg of various brands have been examined, using laser-induced breakdown spectroscopy (LIBS) technique. The statistical methods such as the principal component analysis (PCA) and the partial least square regression analysis (PLSR) have been employed on LIBS spectral data for classifying and developing the calibration models of drug samples. We have developed the ratio-based calibration model applying PLSR in which relative spectral intensity ratios H/C, H/N and O/N are used. Further, the developed model has been employed to predict the relative concentration of element in unknown drug samples. The experiment has been performed in air and argon atmosphere, respectively, and the obtained results have been compared. The present model provides rapid spectroscopic method for drug analysis with high statistical significance for online control and measurement process in a wide variety of pharmaceutical industrial applications.

  18. Planck 2013 results. IX. HFI spectral response

    CERN Document Server

    Ade, P A R; Armitage-Caplan, C; Arnaud, M; Ashdown, M; Atrio-Barandela, F; Aumont, J; Baccigalupi, C; Banday, A J; Barreiro, R B; Battaner, E; Benabed, K; Benoît, A; Benoit-Lévy, A; Bernard, J -P; Bersanelli, M; Bielewicz, P; Bobin, J; Bock, J J; Bond, J R; Borrill, J; Bouchet, F R; Boulanger, F; Bridges, M; Bucher, M; Burigana, C; Cardoso, J -F; Catalano, A; Challinor, A; Chamballu, A; Chary, R -R; Chen, X; Chiang, L -Y; Chiang, H C; Christensen, P R; Church, S; Clements, D L; Colombi, S; Colombo, L P L; Combet, C; Comis, B; Couchot, F; Coulais, A; Crill, B P; Curto, A; Cuttaia, F; Danese, L; Davies, R D; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J -M; Désert, F -X; Dickinson, C; Diego, J M; Dole, H; Donzelli, S; Doré, O; Douspis, M; Dupac, X; Efstathiou, G; Enßlin, T A; Eriksen, H K; Falgarone, E; Finelli, F; Forni, O; Frailis, M; Franceschi, E; Galeotta, S; Ganga, K; Giard, M; Giraud-Héraud, Y; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Hansen, F K; Hanson, D; Harrison, D; Henrot-Versillé, S; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hornstrup, A; Hovest, W; Huffenberger, K M; Hurier, G; Jaffe, T R; Jaffe, A H; Jones, W C; Juvela, M; Keihänen, E; Keskitalo, R; Kisner, T S; Kneissl, R; Knoche, J; Knox, L; Kunz, M; Kurki-Suonio, H; Lagache, G; Lamarre, J -M; Lasenby, A; Laureijs, R J; Lawrence, C R; Leahy, J P; Leonardi, R; Leroy, C; Lesgourgues, J; Liguori, M; Lilje, P B; Linden-Vørnle, M; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; Maffei, B; Mandolesi, N; Maris, M; Marshall, D J; Martin, P G; Martínez-González, E; Masi, S; Matarrese, S; Matthai, F; Mazzotta, P; McGehee, P; Melchiorri, A; Mendes, L; Mennella, A; Migliaccio, M; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, J A; Naselsky, P; Nati, F; Natoli, P; Netterfield, C B; Nørgaard-Nielsen, H U; North, C; Noviello, F; Novikov, D; Novikov, I; Osborne, S; Oxborrow, C A; Paci, F; Pagano, L; Pajot, F; Paoletti, D; Pasian, F; Patanchon, G; Perdereau, O; Perotto, L; Perrotta, F; Piacentini, F; Piat, M; Pierpaoli, E; Pietrobon, D; Plaszczynski, S; Pointecouteau, E; Polenta, G; Ponthieu, N; Popa, L; Poutanen, T; Pratt, G W; Prézeau, G; Prunet, S; Puget, J -L; Rachen, J P; Reinecke, M; Remazeilles, M; Renault, C; Ricciardi, S; Riller, T; Ristorcelli, I; Rocha, G; Rosset, C; Roudier, G; Rusholme, B; Santos, D; Savini, G; Shellard, E P S; Spencer, L D; Starck, J -L; Stolyarov, V; Stompor, R; Sudiwala, R; Sureau, F; Sutton, D; Suur-Uski, A -S; Sygnet, J -F; Tauber, J A; Tavagnacco, D; Terenzi, L; Tomasi, M; Tristram, M; Tucci, M; Umana, G; Valenziano, L; Valiviita, J; Van Tent, B; Vielva, P; Villa, F; Vittorio, N; Wade, L A; Wandelt, B D; Yvon, D; Zacchei, A; Zonca, A

    2014-01-01

    The Planck High Frequency Instrument (HFI) spectral response was determined through a series of ground based tests conducted with the HFI focal plane in a cryogenic environment prior to launch. The main goal of the spectral transmission tests was to measure the relative spectral response (including out-of-band signal rejection) of all HFI detectors. This was determined by measuring the output of a continuously scanned Fourier transform spectrometer coupled with all HFI detectors. As there is no on-board spectrometer within HFI, the ground-based spectral response experiments provide the definitive data set for the relative spectral calibration of the HFI. The spectral response of the HFI is used in Planck data analysis and component separation, this includes extraction of CO emission observed within Planck bands, dust emission, Sunyaev-Zeldovich sources, and intensity to polarization leakage. The HFI spectral response data have also been used to provide unit conversion and colour correction analysis tools. Ver...

  19. CRISS power spectral density

    International Nuclear Information System (INIS)

    Vaeth, W.

    1979-04-01

    The correlation of signal components at different frequencies like higher harmonics cannot be detected by a normal power spectral density measurement, since this technique correlates only components at the same frequency. This paper describes a special method for measuring the correlation of two signal components at different frequencies: the CRISS power spectral density. From this new function in frequency analysis, the correlation of two components can be determined quantitatively either they stem from one signal or from two diverse signals. The principle of the method, suitable for the higher harmonics of a signal as well as for any other frequency combinations is shown for the digital frequency analysis technique. Two examples of CRISS power spectral densities demonstrates the operation of the new method. (orig.) [de

  20. Rapid Preparation of Biosorbents with High Ion Exchange Capacity from Rice Straw and Bagasse for Removal of Heavy Metals

    Directory of Open Access Journals (Sweden)

    Supitcha Rungrodnimitchai

    2014-01-01

    Full Text Available This work describes the preparation of the cellulose phosphate with high ion exchange capacity from rice straw and bagasse for removal of heavy metals. In this study, rice straw and bagasse were modified by the reaction with phosphoric acid in the presence of urea. The introduced phosphoric group is an ion exchangeable site for heavy metal ions. The reaction by microwave heating yielded modified rice straw and modified bagasse with greater ion exchange capacities (∼3.62 meq/g and shorter reaction time (1.5–5.0 min than the phosphorylation by oil bath heating. Adsorption experiments towards Pb2+, Cd2+, and Cr3+ ions of the modified rice straw and the modified bagasse were performed at room temperature (heavy metal concentration 40 ppm, adsorbent 2.0 g/L. The kinetics of adsorption agreed with the pseudo-second-order model. It was shown that the modified rice straw and the modified bagasse could adsorb heavy metal ions faster than the commercial ion exchange resin (Dowax. As a result of Pb2+ sorption test, the modified rice straw (RH-NaOH 450W removed Pb2+ much faster in the initial step and reached 92% removal after 20 min, while Dowax (commercial ion exchange resin took 90 min for the same removal efficiency.

  1. Onboard spectral imager data processor

    Science.gov (United States)

    Otten, Leonard J.; Meigs, Andrew D.; Franklin, Abraham J.; Sears, Robert D.; Robison, Mark W.; Rafert, J. Bruce; Fronterhouse, Donald C.; Grotbeck, Ronald L.

    1999-10-01

    Previous papers have described the concept behind the MightySat II.1 program, the satellite's Fourier Transform imaging spectrometer's optical design, the design for the spectral imaging payload, and its initial qualification testing. This paper discusses the on board data processing designed to reduce the amount of downloaded data by an order of magnitude and provide a demonstration of a smart spaceborne spectral imaging sensor. Two custom components, a spectral imager interface 6U VME card that moves data at over 30 MByte/sec, and four TI C-40 processors mounted to a second 6U VME and daughter card, are used to adapt the sensor to the spacecraft and provide the necessary high speed processing. A system architecture that offers both on board real time image processing and high-speed post data collection analysis of the spectral data has been developed. In addition to the on board processing of the raw data into a usable spectral data volume, one feature extraction technique has been incorporated. This algorithm operates on the basic interferometric data. The algorithm is integrated within the data compression process to search for uploadable feature descriptions.

  2. Nanoparticle Zere-valent Iron Affect on As (V Removal from Drinking Water

    Directory of Open Access Journals (Sweden)

    Hamed Koohpayehzadeh

    2012-10-01

    Full Text Available Arsenic which is present in the underground and surface water is one of the most toxic elements threating human health and animals. Arsenic has been removed in different type of ways. In this study Arsenic removal from drinking water and its decreasing rates were investigated by NZVI (nanoparticle zerovalent iron to standard limit (I.e.  0.01 mg/lit . The tests were conducted on reactor containing 100 ml water containing 1mg/L. Arsenic by virtue of Batch method. The mixture was executed in mixing was done an Oultrasnic device in order to have better mixture and complete distribution of nanoparticles in water. Then the arsenic was removed from the water by VATMAN paper of 0.45 Hm. The remained arsenic in the water was measured by ICP device. In this article the influence of the parameters including mixture time , PH ,NZVI and arcenic doses were examined . Having perfomed many tests the results showed that 1 mg arsenic can be removed 100 percent by 0.05 g NZVI in 8 min. It is possible to remove by 98 percent arsenic in 5-10 PH range. Iron nanopaticle way is an effective and rapid way to remove arsenic from water and various conditions have not considerable effect on it.

  3. Performance evaluation of the PITBULL trademark pump for the removal of hazardous waste

    International Nuclear Information System (INIS)

    Hatchell, B.K.; Combs, W.H.; Hymas, C.R.; Powell, M.R.; Rinker, M.W.; White, M.

    1998-09-01

    One objective of the Waste Removal Project at the Department of Energy's Savannah River Site (SRS) is to explore methods to successfully remove waste heels that will remain in the high-level waste tanks after bulk waste removal has been completed. Tank closure is not possible unless this residue is removed. As much as 151,000 liters of residue can remain after a conventional waste removal campaign. The waste heels can be comprised of sludge, zeolite, and silica. The heels are generally hardened or compacted insoluble particulate with relatively rapid settling velocities. A PITBULL trademark pump is being considered by SRS to retrieve sludge-type waste from Tank 19. Sections 1 through 4 of this report present the scope and objectives of the test program, describe the principles of operation of the PITBULL, and present the test approach, set-up, and instrumentation. Test results, including pumping rates with water and slurry, are provided in Section 5, along with considerations for remote operation. Conclusions and recommendations are provided in Section 6

  4. Precise Multi-Spectral Dermatological Imaging

    DEFF Research Database (Denmark)

    Gomez, David Delgado; Carstensen, Jens Michael; Ersbøll, Bjarne Kjær

    2004-01-01

    In this work, an integrated imaging system to obtain accurate and reproducible multi-spectral dermatological images is proposed. The system is made up of an integrating sphere, light emitting diodes and a generic monochromatic camera. The system can collect up to 10 different spectral bands....... These spectral bands vary from ultraviolet to near infrared. The welldefined and diffuse illumination of the optically closed scene aims to avoid shadows and specular reflections. Furthermore, the system has been developed to guarantee the reproducibility of the collected images. This allows for comparative...

  5. P-wave attenuation in the Pacific slab beneath northeastern Japan revealed by the spectral ratio of intraslab earthquakes

    Science.gov (United States)

    Shiina, Takahiro; Nakajima, Junichi; Matsuzawa, Toru

    2018-05-01

    We investigate P-wave attenuation, Qp-1, in the Pacific slab beneath northeastern (NE) Japan, adopting for the first time the spectral ratio technique for intraslab earthquakes. When seismograms of two earthquakes are recorded at a station and their ray paths to the station are largely overlapped, station-dependent amplification and structural effects on the overlapped rays can be canceled out from the ratio of the spectral amplitudes of the seismograms. Therefore, adopting the spectral ratio technique for intraslab earthquakes has a great advantage for the precise evaluation of Qp-1 in the slab because the structural effects above the slab, including the high-attenuation mantle wedge, are removed. For estimating the intraslab Qp-1, we determined corner frequency of the intraslab earthquakes using the S-coda wave spectral ratio as the first step. Then, we evaluated the inter-event path attenuation, Δt*, from the ratio of the spectral amplitudes of P waves. The obtained result shows that P-wave attenuation in the Pacific slab marks Qp-1 of 0.0015 (Qp of ∼670) at depths of 50-250 km. This indicates that the P-wave attenuation in the Pacific slab is weaker than that in the mantle wedge. The relatively high-Qp-1 is correlated with the distributions of intraslab earthquakes, suggesting that the P-wave amplitude is more attenuated around active seismicity zones in the slab. Therefore, our observations likely indicate the presence of fractures, hydrous minerals, and dehydrated fluid around seismogenic zones in the slab at intermediate depths.

  6. Adsorptive removal of selected pharmaceuticals by mesoporous silica SBA-15

    International Nuclear Information System (INIS)

    Bui, Tung Xuan; Choi, Heechul

    2009-01-01

    The removal of five selected pharmaceuticals, viz., carbamazepine, clofibric acid, diclofenac, ibuprofen, and ketoprofen was examined by batch sorption experiments onto a synthesized mesoporous silica SBA-15. SBA-15 was synthesized and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N 2 adsorption-desorption measurement, and point of zero charge (PZC) measurement. Pharmaceutical adsorption kinetics was rapid and occurred on a scale of minutes, following a pseudo-second-order rate expression. Adsorption isotherms were best fitted by the Freundlich isotherm model. High removal rates of individual pharmaceuticals were achieved in acidic media (pH 3-5) and reached 85.2% for carbamazepine, 88.3% for diclofenac, 93.0% for ibuprofen, 94.3% for ketoprofen, and 49.0% for clofibric acid at pH 3 but decreased with increase in pH. SBA-15 also showed high efficiency for removal of a mixture of 5 pharmaceuticals. Except for clofibric acid (35.6%), the removal of pharmaceuticals in the mixture ranged from 75.2 to 89.3%. Based on adsorption and desorption results, the mechanism of the selected pharmaceuticals was found to be a hydrophilic interaction, providing valuable information for further studies to design materials for the purpose. The results of this study suggest that mesoporous-silica-based materials are promising adsorbents for removing pharmaceuticals from not only surface water but also wastewater of pharmaceutical industrial manufactures.

  7. Adsorptive removal of selected pharmaceuticals by mesoporous silica SBA-15

    Energy Technology Data Exchange (ETDEWEB)

    Bui, Tung Xuan, E-mail: bxtung@gist.ac.kr [Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of); Choi, Heechul, E-mail: hcchoi@gist.ac.kr [Department of Environmental Science and Engineering, Gwangju Institute of Science and Technology (GIST), 261 Cheomdan-gwagiro, Buk-gu, Gwangju 500-712 (Korea, Republic of)

    2009-09-15

    The removal of five selected pharmaceuticals, viz., carbamazepine, clofibric acid, diclofenac, ibuprofen, and ketoprofen was examined by batch sorption experiments onto a synthesized mesoporous silica SBA-15. SBA-15 was synthesized and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), N{sub 2} adsorption-desorption measurement, and point of zero charge (PZC) measurement. Pharmaceutical adsorption kinetics was rapid and occurred on a scale of minutes, following a pseudo-second-order rate expression. Adsorption isotherms were best fitted by the Freundlich isotherm model. High removal rates of individual pharmaceuticals were achieved in acidic media (pH 3-5) and reached 85.2% for carbamazepine, 88.3% for diclofenac, 93.0% for ibuprofen, 94.3% for ketoprofen, and 49.0% for clofibric acid at pH 3 but decreased with increase in pH. SBA-15 also showed high efficiency for removal of a mixture of 5 pharmaceuticals. Except for clofibric acid (35.6%), the removal of pharmaceuticals in the mixture ranged from 75.2 to 89.3%. Based on adsorption and desorption results, the mechanism of the selected pharmaceuticals was found to be a hydrophilic interaction, providing valuable information for further studies to design materials for the purpose. The results of this study suggest that mesoporous-silica-based materials are promising adsorbents for removing pharmaceuticals from not only surface water but also wastewater of pharmaceutical industrial manufactures.

  8. A review of computer-aided design/computer-aided manufacture techniques for removable denture fabrication

    Science.gov (United States)

    Bilgin, Mehmet Selim; Baytaroğlu, Ebru Nur; Erdem, Ali; Dilber, Erhan

    2016-01-01

    The aim of this review was to investigate usage of computer-aided design/computer-aided manufacture (CAD/CAM) such as milling and rapid prototyping (RP) technologies for removable denture fabrication. An electronic search was conducted in the PubMed/MEDLINE, ScienceDirect, Google Scholar, and Web of Science databases. Databases were searched from 1987 to 2014. The search was performed using a variety of keywords including CAD/CAM, complete/partial dentures, RP, rapid manufacturing, digitally designed, milled, computerized, and machined. The identified developments (in chronological order), techniques, advantages, and disadvantages of CAD/CAM and RP for removable denture fabrication are summarized. Using a variety of keywords and aiming to find the topic, 78 publications were initially searched. For the main topic, the abstract of these 78 articles were scanned, and 52 publications were selected for reading in detail. Full-text of these articles was gained and searched in detail. Totally, 40 articles that discussed the techniques, advantages, and disadvantages of CAD/CAM and RP for removable denture fabrication and the articles were incorporated in this review. Totally, 16 of the papers summarized in the table. Following review of all relevant publications, it can be concluded that current innovations and technological developments of CAD/CAM and RP allow the digitally planning and manufacturing of removable dentures from start to finish. As a result according to the literature review CAD/CAM techniques and supportive maxillomandibular relationship transfer devices are growing fast. In the close future, fabricating removable dentures will become medical informatics instead of needing a technical staff and procedures. However the methods have several limitations for now. PMID:27095912

  9. Climate engineering and the risk of rapid climate change

    International Nuclear Information System (INIS)

    Ross, Andrew; Damon Matthews, H

    2009-01-01

    Recent research has highlighted risks associated with the use of climate engineering as a method of stabilizing global temperatures, including the possibility of rapid climate warming in the case of abrupt removal of engineered radiative forcing. In this study, we have used a simple climate model to estimate the likely range of temperature changes associated with implementation and removal of climate engineering. In the absence of climate engineering, maximum annual rates of warming ranged from 0.015 to 0.07 deg. C/year, depending on the model's climate sensitivity. Climate engineering resulted in much higher rates of warming, with the temperature change in the year following the removal of climate engineering ranging from 0.13 to 0.76 deg. C. High rates of temperature change were sustained for two decades following the removal of climate engineering; rates of change of 0.5 (0.3,0.1) deg. C/decade were exceeded over a 20 year period with 15% (75%, 100%) likelihood. Many ecosystems could be negatively affected by these rates of temperature change; our results suggest that climate engineering in the absence of deep emissions cuts could arguably constitute increased risk of dangerous anthropogenic interference in the climate system under the criteria laid out in the United Nations Framework Convention on Climate Change.

  10. Contaminant removal by wastewater treatment plants in the Stillaguamish River Basin, Washington

    Science.gov (United States)

    Barbash, Jack E.; Moran, Patrick W.; Wagner, Richard J.; Wolanek, Michael

    2015-01-01

    Human activities in most areas of the developed world typically release nutrients, pharmaceuticals, personal care products, pesticides, and other contaminants into the environment, many of which reach freshwater ecosystems. In urbanized areas, wastewater treatment plants (WWTPs) are critical facilities for collecting and reducing the amounts of wastewater contaminants (WWCs) that ultimately discharge to rivers, coastal areas, and groundwater. Most WWTPs use multiple methods to remove contaminants from wastewater. These include physical methods to remove solid materials (primary treatment), biological and chemical methods to remove most organic matter (secondary treatment), advanced methods to reduce the concentrations of various contaminants such as nitrogen, phosphorus and (or) synthetic organic compounds (tertiary treatment), and disinfection prior to discharge (Metcalf and Eddy, Inc., 1979). This study examined the extent to which 114 organic WWCs were removed by each of three WWTPs, prior to discharge to freshwater and marine ecosystems, in a rapidly developing area in northwestern Washington State. Removal percentages for each WWC were estimated by comparing the concentrations measured in the WWTP influents with those measured in the effluents. The investigation was carried out in the 700-mi2Stillaguamish River Basin, the fifth largest watershed that discharges to Puget Sound (fig. 1).

  11. Removal of symptomatic craniofacial titanium hardware following craniotomy: Case series and review

    Directory of Open Access Journals (Sweden)

    Sheri K. Palejwala

    2015-06-01

    Full Text Available Titanium craniofacial hardware has become commonplace for reconstruction and bone flap fixation following craniotomy. Complications of titanium hardware include palpability, visibility, infection, exposure, pain, and hardware malfunction, which can necessitate hardware removal. We describe three patients who underwent craniofacial reconstruction following craniotomies for trauma with post-operative courses complicated by medically intractable facial pain. All three patients subsequently underwent removal of the symptomatic craniofacial titanium hardware and experienced rapid resolution of their painful parasthesias. Symptomatic plates were found in the region of the frontozygomatic suture or MacCarty keyhole, or in close proximity with the supraorbital nerve. Titanium plates, though relatively safe and low profile, can cause local nerve irritation or neuropathy. Surgeons should be cognizant of the potential complications of titanium craniofacial hardware and locations that are at higher risk for becoming symptomatic necessitating a second surgery for removal.

  12. Methods for measuring the spectral reflectivity of advanced materials at high temperature

    International Nuclear Information System (INIS)

    Salikhov, T.P.; Kan, V.V.

    1993-01-01

    For investigation in the domain of advanced materials as well as for new technologies there is an urgent need for knowledge of the spectral reflectivity of the materials specially at high temperatures. However the methods available are mostly intended for measuring the model materials with specular or diffuse reflection surface. This is not quite correct since advanced materials have mixed specular diffuse reflection surfaces. New methods for reflectivity measurements of materials in the visible, near and middle infrared range at high temperature, regardless of surface texture, have been developed. The advantages of the methods proposed are as flows: (a) the facility of performing the reflectivity measurements for materials with mixed specular diffuse reflectance; (b) wide spectral range 0,38-8 micro m; (c) wide temperature range 300-3000 K; (d) high accuracy and rapid measurements. The methods are based on the following principals (i) Diffuse irradiation of the sample surface and the use of Helkholtz reciprocity principle to determine the directional hemispherical reflectivity ii) Pulse polychromatic probing of the sample by additional light source. The first principle excludes the influence of the angular reflection distribution of sample surface on data obtained. The second principle gives the possibility of simultaneous measurements of the reflectivity. The second principle gives the possibility of simultaneous measurements of the reflectivity in wide spectral range. On the basis of these principles for high temperature reflectometers have been developed and discussed here. (author)

  13. Localized removal of layers of metal, polymer, or biomaterial by ultrasound cavitation bubbles

    NARCIS (Netherlands)

    Rivas, David Fernandez; Verhaagen, Bram; Seddon, James R. T.; Zijlstra, Aaldert G.; Jiang, Lei-Meng; van der Sluis, Luc W. M.; Versluis, Michel; Lohse, Detlef; Gardeniers, Han J. G. E.

    We present an ultrasonic device with the ability to locally remove deposited layers from a glass slide in a controlled and rapid manner. The cleaning takes place as the result of cavitating bubbles near the deposited layers and not due to acoustic streaming. The bubbles are ejected from air-filled

  14. Localized removal of layers of metal, polymer, or biomaterial by ultrasound cavitation bubbles

    NARCIS (Netherlands)

    Fernandez Rivas, David; Verhaagen, B.; Seddon, James Richard Thorley; Zijlstra, A.G.; Jiang, L.M.; van der Sluis, L.W.M.; Versluis, Michel; Lohse, Detlef; Gardeniers, Johannes G.E.

    2012-01-01

    We present an ultrasonic device with the ability to locally remove deposited layers from a glass slide in a controlled and rapid manner. The cleaning takes place as the result of cavitating bubbles near the deposited layers and not due to acoustic streaming. The bubbles are ejected from air-filled

  15. Curvature Effect and the Spectral Softening Phenomenon Detected ...

    Indian Academy of Sciences (India)

    soft spectral evolution, indicating that this spectral softening is not a rare phenomenon .... of time, there exists a temporal steep decay phase accompanied by spectral softening. (d) In most cases, the temporal power law index α and the spectral.

  16. Spectral properties of 441 radio pulsars

    Science.gov (United States)

    Jankowski, F.; van Straten, W.; Keane, E. F.; Bailes, M.; Barr, E. D.; Johnston, S.; Kerr, M.

    2018-02-01

    We present a study of the spectral properties of 441 pulsars observed with the Parkes radio telescope near the centre frequencies of 728, 1382 and 3100 MHz. The observations at 728 and 3100 MHz were conducted simultaneously using the dual-band 10-50 cm receiver. These high-sensitivity, multifrequency observations provide a systematic and uniform sample of pulsar flux densities. We combine our measurements with spectral data from the literature in order to derive the spectral properties of these pulsars. Using techniques from robust regression and information theory, we classify the observed spectra in an objective, robust and unbiased way into five morphological classes: simple or broken power law, power law with either low- or high-frequency cut-off and log-parabolic spectrum. While about 79 per cent of the pulsars that could be classified have simple power-law spectra, we find significant deviations in 73 pulsars, 35 of which have curved spectra, 25 with a spectral break and 10 with a low-frequency turn-over. We identify 11 gigahertz-peaked spectrum (GPS) pulsars, with 3 newly identified in this work and 8 confirmations of known GPS pulsars; 3 others show tentative evidence of GPS, but require further low-frequency measurements to support this classification. The weighted mean spectral index of all pulsars with simple power-law spectra is -1.60 ± 0.03. The observed spectral indices are well described by a shifted log-normal distribution. The strongest correlations of spectral index are with spin-down luminosity, magnetic field at the light-cylinder and spin-down rate. We also investigate the physical origin of the observed spectral features and determine emission altitudes for three pulsars.

  17. Rapid method to determine actinides and 89/90Sr in limestone and marble samples

    International Nuclear Information System (INIS)

    Maxwell, S.L.; Culligan, Brian; Hutchison, J.B.; Utsey, R.C.; Sudowe, Ralf; McAlister, D.R.

    2016-01-01

    A new method for the determination of actinides and radiostrontium in limestone and marble samples has been developed that utilizes a rapid sodium hydroxide fusion to digest the sample. Following rapid pre-concentration steps to remove sample matrix interferences, the actinides and 89 / 90 Sr are separated using extraction chromatographic resins and measured radiometrically. The advantages of sodium hydroxide fusion versus other fusion techniques will be discussed. This approach has a sample preparation time for limestone and marble samples of <4 h. (author)

  18. Spectral emissivity of tungsten: analytic expressions for the 340-nm to 2.6-μm spectral region

    International Nuclear Information System (INIS)

    Pon, R.M.; Hessler, J.P.

    1984-01-01

    To correct emission spectra a standard radiance source is often used to determine the spectral responsivity of the detection system. In the near-UV, visible, and near-IR spectral regions the most common radiance standard is a tungsten strip lamp calibrated by a standards laboratory. For day-to-day experiments where slightly less accuracy is acceptable, a less expensive uncalibrated lamp is useful. In this case, the radiant temperature T/sub r/ of the lamp is measured with an optical pyrometer, generally at a single wavelength such as 650 nm, and the source spectral radiance L(λ) is calculated from L(λ) = tau(λ)epsilon(λ,T)L/sub B/(λ,T). The transmittance of the source is tau(λ), the spectral emissivity is epsilon(λ,T), and L/sub B/(λ,T) is the spectral distribution of blackbody radiation, Planck's radiation law. To obtain the true temperature T, Wien's approximation is employed. To conveniently calibrate a system, especially one which utilizes a microcomputer, it is advantageous to have analytic expressions for the spectral emissivity of tungsten. Although Larrabee has published such expressions, they are limited to the 450-800-nm spectral region. To obtain analytic expressions from 340 nm to 2.6 μm they have used the measurements of DeVos. Although DeVos's results differ by 2% from those of Larrabee, this difference is assumed to be acceptable

  19. Phosphate and arsenate removal efficiency by thermostable ferritin enzyme from Pyrococcus furiosus using radioisotopes

    KAUST Repository

    Sevcenco, Ana-Maria

    2015-03-13

    Oxo-anion binding properties of the thermostable enzyme ferritin from Pyrococcus furiosus were characterized with radiography. Radioisotopes 32P and 76As present as oxoanions were used to measure the extent and the rate of their absorption by the ferritin. Thermostable ferritin proved to be an excellent system for rapid phosphate and arsenate removal from aqueous solutions down to residual concentrations at the picomolar level. These very low concentrations make thermostable ferritin a potential tool to considerably mitigate industrial biofouling by phosphate limitation or to remove arsenate from drinking water.

  20. The Sturm-Liouville inverse spectral problem with boundary conditions depending on the spectral parameter

    Directory of Open Access Journals (Sweden)

    Cornelis van der Mee

    2005-01-01

    Full Text Available We present the complete version including proofs of the results announced in [van der Mee C., Pivovarchik V.: A Sturm-Liouville spectral problem with boundary conditions depending on the spectral parameter. Funct. Anal. Appl. 36 (2002, 315–317 [Funkts. Anal. Prilozh. 36 (2002, 74–77 (Russian

  1. Spectrally-engineered solar thermal photovoltaic devices

    Science.gov (United States)

    Lenert, Andrej; Bierman, David; Chan, Walker; Celanovic, Ivan; Soljacic, Marin; Wang, Evelyn N.; Nam, Young Suk; McEnaney, Kenneth; Kraemer, Daniel; Chen, Gang

    2018-03-27

    A solar thermal photovoltaic device, and method of forming same, includes a solar absorber and a spectrally selective emitter formed on either side of a thermally conductive substrate. The solar absorber is configured to absorb incident solar radiation. The solar absorber and the spectrally selective emitter are configured with an optimized emitter-to-absorber area ratio. The solar thermal photovoltaic device also includes a photovoltaic cell in thermal communication with the spectrally selective emitter. The spectrally selective emitter is configured to permit high emittance for energies above a bandgap of the photovoltaic cell and configured to permit low emittance for energies below the bandgap.

  2. Spacetime Discontinuous Galerkin FEM: Spectral Response

    International Nuclear Information System (INIS)

    Abedi, R; Omidi, O; Clarke, P L

    2014-01-01

    Materials in nature demonstrate certain spectral shapes in terms of their material properties. Since successful experimental demonstrations in 2000, metamaterials have provided a means to engineer materials with desired spectral shapes for their material properties. Computational tools are employed in two different aspects for metamaterial modeling: 1. Mircoscale unit cell analysis to derive and possibly optimize material's spectral response; 2. macroscale to analyze their interaction with conventional material. We compare two different approaches of Time-Domain (TD) and Frequency Domain (FD) methods for metamaterial applications. Finally, we discuss advantages of the TD method of Spacetime Discontinuous Galerkin finite element method (FEM) for spectral analysis of metamaterials

  3. Rapidly reconfigurable high-fidelity optical arbitrary waveform generation in heterogeneous photonic integrated circuits.

    Science.gov (United States)

    Feng, Shaoqi; Qin, Chuan; Shang, Kuanping; Pathak, Shibnath; Lai, Weicheng; Guan, Binbin; Clements, Matthew; Su, Tiehui; Liu, Guangyao; Lu, Hongbo; Scott, Ryan P; Ben Yoo, S J

    2017-04-17

    This paper demonstrates rapidly reconfigurable, high-fidelity optical arbitrary waveform generation (OAWG) in a heterogeneous photonic integrated circuit (PIC). The heterogeneous PIC combines advantages of high-speed indium phosphide (InP) modulators and low-loss, high-contrast silicon nitride (Si3N4) arrayed waveguide gratings (AWGs) so that high-fidelity optical waveform syntheses with rapid waveform updates are possible. The generated optical waveforms spanned a 160 GHz spectral bandwidth starting from an optical frequency comb consisting of eight comb lines separated by 20 GHz channel spacing. The Error Vector Magnitude (EVM) values of the generated waveforms were approximately 16.4%. The OAWG module can rapidly and arbitrarily reconfigure waveforms upon every pulse arriving at 2 ns repetition time. The result of this work indicates the feasibility of truly dynamic optical arbitrary waveform generation where the reconfiguration rate or the modulator bandwidth must exceed the channel spacing of the AWG and the optical frequency comb.

  4. Modified magnetite nanoparticles with cetyltrimethylammonium bromide as superior adsorbent for rapid removal of the disperse dyes from wastewater of textile companies

    Directory of Open Access Journals (Sweden)

    Ali Asghar Rajabi

    2016-01-01

    Full Text Available This paper reports application of cetyltrimethylammonium bromide (CTAB coated magnetite nanoparticles (Fe3O4 NPs as a novel adsorbent for removal of two types of disperse dyes, including disperse red 167, and disperse blue 183, from wastewater of textile companies. The effect of parameters including type of surfactant, pH of solution, surfactant concentration, and amount of salt, was investigated and optimized. The obtained results showed that the ratio of initial dye concentration to CTAB amounts has critical effect on removal processes so that removal efficiencies higher than 95% can be achieved even at high concentration of dyes as high as 500 mg l-1 when the ratio is optimum. Removal of dyes is very fast, and equilibrium is reached at times less than 10 min even for high concentration of the dyes. Very high adsorbent capacity (as high as 2000 mg g-1 was yielded for maximum tested concentration of the dyes (500 mg g-1. The obtained result was confirmed by thermogravimetric analysis data. This study showed that CTAB coated Fe3O4 NPs is a very efficient adsorbent for removal of dyes from wastewater of textile companies and has high capacity under optimum conditions.

  5. Multi-spectral optical absorption in substrate-free nanowire arrays

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Junpeng; Chia, Andrew; Boulanger, Jonathan; LaPierre, Ray, E-mail: lapierr@mcmaster.ca [Department of Engineering Physics, McMaster University, 1280 Main St. West, Hamilton, Ontario L8S 4L7 (Canada); Dhindsa, Navneet; Khodadad, Iman; Saini, Simarjeet [Department of Electrical and Computer Engineering, University of Waterloo, 200 University Ave West, Waterloo, Ontario N2L 3G1 (Canada); Waterloo Institute of Nanotechnology, University of Waterloo, 200 University Ave West, Waterloo, Ontario N2L 3G1 (Canada)

    2014-09-22

    A method is presented of fabricating gallium arsenide (GaAs) nanowire arrays of controlled diameter and period by reactive ion etching of a GaAs substrate containing an indium gallium arsenide (InGaP) etch stop layer, allowing the precise nanowire length to be controlled. The substrate is subsequently removed by selective etching, using the same InGaP etch stop layer, to create a substrate-free GaAs nanowire array. The optical absorptance of the nanowire array was then directly measured without absorption from a substrate. We directly observe absorptance spectra that can be tuned by the nanowire diameter, as explained with rigorous coupled wave analysis. These results illustrate strong optical absorption suitable for nanowire-based solar cells and multi-spectral absorption for wavelength discriminating photodetectors. The solar-weighted absorptance above the bandgap of GaAs was 94% for a nanowire surface coverage of only 15%.

  6. Evaluating the Performance of Iron Nano-particle Resin in Removing Fluoride from Water

    Directory of Open Access Journals (Sweden)

    Amir Hossein Mahvi

    2011-01-01

    Full Text Available Excessive amounts of fluoride in drinking water pose serious health problems. It is, therefore, essential to remove it from drinking water by appropriate water treatment processes down to standard levels for preventing the health risks associated. The aim of this study was to determine the performance of a kind of hybrid sorbent resin in removing fluoride from water. Batch experiments were performed to investigate adsorption isotherms and the effects of experimental parameters such as contact time (5-120 min and pH (3-9. Results revealed that fluoride adsorption rate was initially rapid but continued at a slower rate before it reached equilibrium in 120 min. Optimum fluoride removal was observed at a pH range of 3-5.5. The data obtained from the experiments were fitted with Langmiur model.

  7. Spectral quality requirements for effluent identification

    Science.gov (United States)

    Czerwinski, R. N.; Seeley, J. A.; Wack, E. C.

    2005-11-01

    We consider the problem of remotely identifying gaseous materials using passive sensing of long-wave infrared (LWIR) spectral features at hyperspectral resolution. Gaseous materials are distinguishable in the LWIR because of their unique spectral fingerprints. A sensor degraded in capability by noise or limited spectral resolution, however, may be unable to positively identify contaminants, especially if they are present in low concentrations or if the spectral library used for comparisons includes materials with similar spectral signatures. This paper will quantify the relative importance of these parameters and express the relationships between them in a functional form which can be used as a rule of thumb in sensor design or in assessing sensor capability for a specific task. This paper describes the simulation of remote sensing datacontaining a gas cloud.In each simulation, the spectra are degraded in spectral resolution and through the addition of noise to simulate spectra collected by sensors of varying design and capability. We form a trade space by systematically varying the number of sensor spectral channels and signal-to-noise ratio over a range of values. For each scenario, we evaluate the capability of the sensor for gas identification by computing the ratio of the F-statistic for the truth gas tothe same statistic computed over the rest of the library.The effect of the scope of the library is investigated as well, by computing statistics on the variability of the identification capability as the library composition is varied randomly.

  8. Identification of mineral compositions in some renal calculi by FT Raman and IR spectral analysis

    Science.gov (United States)

    Tonannavar, J.; Deshpande, Gouri; Yenagi, Jayashree; Patil, Siddanagouda B.; Patil, Nikhil A.; Mulimani, B. G.

    2016-02-01

    We present in this paper accurate and reliable Raman and IR spectral identification of mineral constituents in nine samples of renal calculi (kidney stones) removed from patients suffering from nephrolithiasis. The identified mineral components include Calcium Oxalate Monohydrate (COM, whewellite), Calcium Oxalate Dihydrate (COD, weddellite), Magnesium Ammonium Phosphate Hexahydrate (MAPH, struvite), Calcium Hydrogen Phosphate Dihydrate (CHPD, brushite), Pentacalcium Hydroxy Triphosphate (PCHT, hydroxyapatite) and Uric Acid (UA). The identification is based on a satisfactory assignment of all the observed IR and Raman bands (3500-400 cm- 1) to chemical functional groups of mineral components in the samples, aided by spectral analysis of pure materials of COM, MAPH, CHPD and UA. It is found that the eight samples are composed of COM as the common component, the other mineral species as common components are: MAPH in five samples, PCHT in three samples, COD in three samples, UA in three samples and CHPD in two samples. One sample is wholly composed of UA as a single component; this inference is supported by the good agreement between ab initio density functional theoretical spectra and experimental spectral measurements of both sample and pure material. A combined application of Raman and IR techniques has shown that, where the IR is ambiguous, the Raman analysis can differentiate COD from COM and PCHT from MAPH.

  9. Identification of mineral compositions in some renal calculi by FT Raman and IR spectral analysis.

    Science.gov (United States)

    Tonannavar, J; Deshpande, Gouri; Yenagi, Jayashree; Patil, Siddanagouda B; Patil, Nikhil A; Mulimani, B G

    2016-02-05

    We present in this paper accurate and reliable Raman and IR spectral identification of mineral constituents in nine samples of renal calculi (kidney stones) removed from patients suffering from nephrolithiasis. The identified mineral components include Calcium Oxalate Monohydrate (COM, whewellite), Calcium Oxalate Dihydrate (COD, weddellite), Magnesium Ammonium Phosphate Hexahydrate (MAPH, struvite), Calcium Hydrogen Phosphate Dihydrate (CHPD, brushite), Pentacalcium Hydroxy Triphosphate (PCHT, hydroxyapatite) and Uric Acid (UA). The identification is based on a satisfactory assignment of all the observed IR and Raman bands (3500-400c m(-1)) to chemical functional groups of mineral components in the samples, aided by spectral analysis of pure materials of COM, MAPH, CHPD and UA. It is found that the eight samples are composed of COM as the common component, the other mineral species as common components are: MAPH in five samples, PCHT in three samples, COD in three samples, UA in three samples and CHPD in two samples. One sample is wholly composed of UA as a single component; this inference is supported by the good agreement between ab initio density functional theoretical spectra and experimental spectral measurements of both sample and pure material. A combined application of Raman and IR techniques has shown that, where the IR is ambiguous, the Raman analysis can differentiate COD from COM and PCHT from MAPH. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Information-efficient spectral imaging sensor

    Science.gov (United States)

    Sweatt, William C.; Gentry, Stephen M.; Boye, Clinton A.; Grotbeck, Carter L.; Stallard, Brian R.; Descour, Michael R.

    2003-01-01

    A programmable optical filter for use in multispectral and hyperspectral imaging. The filter splits the light collected by an optical telescope into two channels for each of the pixels in a row in a scanned image, one channel to handle the positive elements of a spectral basis filter and one for the negative elements of the spectral basis filter. Each channel for each pixel disperses its light into n spectral bins, with the light in each bin being attenuated in accordance with the value of the associated positive or negative element of the spectral basis vector. The spectral basis vector is constructed so that its positive elements emphasize the presence of a target and its negative elements emphasize the presence of the constituents of the background of the imaged scene. The attenuated light in the channels is re-imaged onto separate detectors for each pixel and then the signals from the detectors are combined to give an indication of the presence or not of the target in each pixel of the scanned scene. This system provides for a very efficient optical determination of the presence of the target, as opposed to the very data intensive data manipulations that are required in conventional hyperspectral imaging systems.

  11. Spectral theory of linear operators and spectral systems in Banach algebras

    CERN Document Server

    Müller, Vladimir

    2003-01-01

    This book is dedicated to the spectral theory of linear operators on Banach spaces and of elements in Banach algebras. It presents a survey of results concerning various types of spectra, both of single and n-tuples of elements. Typical examples are the one-sided spectra, the approximate point, essential, local and Taylor spectrum, and their variants. The theory is presented in a unified, axiomatic and elementary way. Many results appear here for the first time in a monograph. The material is self-contained. Only a basic knowledge of functional analysis, topology, and complex analysis is assumed. The monograph should appeal both to students who would like to learn about spectral theory and to experts in the field. It can also serve as a reference book. The present second edition contains a number of new results, in particular, concerning orbits and their relations to the invariant subspace problem. This book is dedicated to the spectral theory of linear operators on Banach spaces and of elements in Banach alg...

  12. Rapid identification of bacteria in positive blood culture broths by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

    Science.gov (United States)

    Stevenson, Lindsay G; Drake, Steven K; Murray, Patrick R

    2010-02-01

    Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry is a rapid, accurate method for identifying bacteria and fungi recovered on agar culture media. We report herein a method for the direct identification of bacteria in positive blood culture broths by MALDI-TOF mass spectrometry. A total of 212 positive cultures were examined, representing 32 genera and 60 species or groups. The identification of bacterial isolates by MALDI-TOF mass spectrometry was compared with biochemical testing, and discrepancies were resolved by gene sequencing. No identification (spectral score of blood culture broth. Of the bacteria with a spectral score of > or = 1.7, 162 (95.3%) of 170 isolates were correctly identified. All 8 isolates of Streptococcus mitis were misidentified as being Streptococcus pneumoniae isolates. This method provides a rapid, accurate, definitive identification of bacteria within 1 h of detection in positive blood cultures with the caveat that the identification of S. pneumoniae would have to be confirmed by an alternative test.

  13. Developement of the method for realization of spectral irradiance scale featuring system of spectral comparisons

    International Nuclear Information System (INIS)

    Skerovic, V; Zarubica, V; Aleksic, M; Zekovic, L; Belca, I

    2010-01-01

    Realization of the scale of spectral responsivity of the detectors in the Directorate of Measures and Precious Metals (DMDM) is based on silicon detectors traceable to LNE-INM. In order to realize the unit of spectral irradiance in the laboratory for photometry and radiometry of the Bureau of Measures and Precious Metals, the new method based on the calibration of the spectroradiometer by comparison with standard detector has been established. The development of the method included realization of the System of Spectral Comparisons (SSC), together with the detector spectral responsivity calibrations by means of a primary spectrophotometric system. The linearity testing and stray light analysis were preformed to characterize the spectroradiometer. Measurement of aperture diameter and calibration of transimpedance amplifier were part of the overall experiment. In this paper, the developed method is presented and measurement results with the associated measurement uncertainty budget are shown.

  14. Developement of the method for realization of spectral irradiance scale featuring system of spectral comparisons

    Energy Technology Data Exchange (ETDEWEB)

    Skerovic, V; Zarubica, V; Aleksic, M [Directorate of measures and precious metals, Optical radiation Metrology department, Mike Alasa 14, 11000 Belgrade (Serbia); Zekovic, L; Belca, I, E-mail: vladanskerovic@dmdm.r [Faculty of Physics, Department for Applied physics and metrology, Studentski trg 12-16, 11000 Belgrade (Serbia)

    2010-10-15

    Realization of the scale of spectral responsivity of the detectors in the Directorate of Measures and Precious Metals (DMDM) is based on silicon detectors traceable to LNE-INM. In order to realize the unit of spectral irradiance in the laboratory for photometry and radiometry of the Bureau of Measures and Precious Metals, the new method based on the calibration of the spectroradiometer by comparison with standard detector has been established. The development of the method included realization of the System of Spectral Comparisons (SSC), together with the detector spectral responsivity calibrations by means of a primary spectrophotometric system. The linearity testing and stray light analysis were preformed to characterize the spectroradiometer. Measurement of aperture diameter and calibration of transimpedance amplifier were part of the overall experiment. In this paper, the developed method is presented and measurement results with the associated measurement uncertainty budget are shown.

  15. Cochlear implant users' spectral ripple resolution.

    Science.gov (United States)

    Jeon, Eun Kyung; Turner, Christopher W; Karsten, Sue A; Henry, Belinda A; Gantz, Bruce J

    2015-10-01

    This study revisits the issue of the spectral ripple resolution abilities of cochlear implant (CI) users. The spectral ripple resolution of recently implanted CI recipients (implanted during the last 10 years) were compared to those of CI recipients implanted 15 to 20 years ago, as well as those of normal-hearing and hearing-impaired listeners from previously published data from Henry, Turner, and Behrens [J. Acoust. Soc. Am. 118, 1111-1121 (2005)]. More recently, implanted CI recipients showed significantly better spectral ripple resolution. There is no significant difference in spectral ripple resolution for these recently implanted subjects compared to hearing-impaired (acoustic) listeners. The more recently implanted CI users had significantly better pre-operative speech perception than previously reported CI users. These better pre-operative speech perception scores in CI users from the current study may be related to better performance on the spectral ripple discrimination task; however, other possible factors such as improvements in internal and external devices cannot be excluded.

  16. 2-Hydroxy-naphthyl functionalized mesoporous silica for fluorescence sensing and removal of aluminum ions.

    Science.gov (United States)

    Das, Trisha; Roy, Ankita; Uyama, Hiroshi; Roy, Partha; Nandi, Mahasweta

    2017-06-06

    Mesoporous silica functionalized with a 2-hydroxy-naphthyl moiety has been synthesized and characterized by standard techniques like powder X-ray diffraction, N 2 adsorption/desorption studies, transmission electron microscopy and spectral studies like FT-IR, UV-visible, fluorescence and 13 C and 29 Si solid state NMR. The functionalized silica material showed significant enhancement in its emission intensity in the presence of Al 3+ ions whereas other metal ions could not bring about any increase in its emission intensity. They either quench the emission or do not alter the intensity significantly making the functionalized material a fluorescence chemosensor for Al 3+ . The sensitivity of the probe towards Al 3+ has been determined to be high with a low limit of detection value. As functionalized silica is not soluble in common solvents, it has been effectively used to bind and remove Al 3+ from a solution. Theoretical calculations on a model system have been performed to investigate the electronic spectral transitions.

  17. Nasal mass removal in the koala (Phascolarctos cinereus).

    Science.gov (United States)

    Bercier, Marjorie; Wynne, Janna; Klause, Stephen; Stadler, Cynthia K; Gorow, April; Pye, Geoffrey W

    2012-12-01

    Nasal masses in the koala (Phascolarctos cinereus) are not uncommon and can be challenging to diagnose and treat. Differential diagnoses for nasal masses in the koala are cryptococcal granulomas, nasal polyps, nasal adenocarcinoma, and osteochondromatosis. This report describes successful surgical approaches for two adult koalas with nasal masses and includes photodocumentation and description of the anatomy of the koala nasal passages from the postmortem transverse sectioning of a normal koala head. Surgical removal of the nasal masses in these koalas resulted in a rapid resolution of clinical signs.

  18. Removal of Cr(VI) from aqueous solution by fungal biomass

    Energy Technology Data Exchange (ETDEWEB)

    Ahluwalia, Sarabjeet Singh [Department of Biotechnology, General Shivdev Singh Diwan Gurbachan Singh Khalsa College, Patiala, Punjab (India); Goyal, Dinesh [Department of Biotechnology and Environmental Sciences, Thapar University, Patiala, Punjab (India)

    2010-10-15

    Chromium compounds are released by industrial processes including leather production, mining, petroleum refining, in textile industry and dyeing. They are a significant threat to the environment and public health because of their toxicity. Removal of hexavalent chromium by living biomass of different fungi was effective in the order of Aspergillus terricola>Aspergillus niger>Acremonium strictum>Aureobasidium pullulans>Paecilomyces variotii>Aspergillus foetidus>Cladosporium resinae>Phanerochaete chrysosporium. Non-living dried fungal biomass showed higher potential for metal removal than living cells. Among all fungi dead biomass of P. chrysosporium, C. resinae and P. variotii had the maximum specific chromium uptake capacity, which was 11.02, 10.69 and 10.35 mg/g of dry biomass respectively at pH 4.0-5.0 in batch sorption. Removal of Cr(VI) by P. chrysosporium from multi-metallic synthetic solution as well as chrome effluent was significant by bringing down the residual concentration to 0.1 mg/L in the effluent, which falls within the permissible range and its removal was not affected by the presence of other metal ions such as Fe, Zn and Ni. Fourier transform infrared spectral analysis revealed the presence of carboxylate (C=O) and amine (-NH{sup +}{sub 3}-NH{sup +}{sub 2}) functional groups commonly present on the cell surface of all fungi, with possible involvement in chromium binding. The result indicates that non-living fungal biomass either obtained as a by-product of fermentation industry or mass produced using inexpensive culture media can be used for bioremediation of Cr(VI) from chrome effluent on large scale. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Spectral dimension in causal set quantum gravity

    International Nuclear Information System (INIS)

    Eichhorn, Astrid; Mizera, Sebastian

    2014-01-01

    We evaluate the spectral dimension in causal set quantum gravity by simulating random walks on causal sets. In contrast to other approaches to quantum gravity, we find an increasing spectral dimension at small scales. This observation can be connected to the nonlocality of causal set theory that is deeply rooted in its fundamentally Lorentzian nature. Based on its large-scale behaviour, we conjecture that the spectral dimension can serve as a tool to distinguish causal sets that approximate manifolds from those that do not. As a new tool to probe quantum spacetime in different quantum gravity approaches, we introduce a novel dimensional estimator, the causal spectral dimension, based on the meeting probability of two random walkers, which respect the causal structure of the quantum spacetime. We discuss a causal-set example, where the spectral dimension and the causal spectral dimension differ, due to the existence of a preferred foliation. (paper)

  20. ARSENIC REMOVAL BY IRON REMOVAL PROCESSES

    Science.gov (United States)

    Presentation will discuss the removal of arsenic from drinking water using iron removal processes that include oxidation/filtration and the manganese greensand processes. Presentation includes results of U.S. EPA field studies conducted in Michigan and Ohio on existing iron remo...

  1. A Simple Spectral Observer

    Directory of Open Access Journals (Sweden)

    Lizeth Torres

    2018-05-01

    Full Text Available The principal aim of a spectral observer is twofold: the reconstruction of a signal of time via state estimation and the decomposition of such a signal into the frequencies that make it up. A spectral observer can be catalogued as an online algorithm for time-frequency analysis because is a method that can compute on the fly the Fourier transform (FT of a signal, without having the entire signal available from the start. In this regard, this paper presents a novel spectral observer with an adjustable constant gain for reconstructing a given signal by means of the recursive identification of the coefficients of a Fourier series. The reconstruction or estimation of a signal in the context of this work means to find the coefficients of a linear combination of sines a cosines that fits a signal such that it can be reproduced. The design procedure of the spectral observer is presented along with the following applications: (1 the reconstruction of a simple periodical signal, (2 the approximation of both a square and a triangular signal, (3 the edge detection in signals by using the Fourier coefficients, (4 the fitting of the historical Bitcoin market data from 1 December 2014 to 8 January 2018 and (5 the estimation of a input force acting upon a Duffing oscillator. To round out this paper, we present a detailed discussion about the results of the applications as well as a comparative analysis of the proposed spectral observer vis-à-vis the Short Time Fourier Transform (STFT, which is a well-known method for time-frequency analysis.

  2. Spectral characterization of natural backgrounds

    Science.gov (United States)

    Winkelmann, Max

    2017-10-01

    As the distribution and use of hyperspectral sensors is constantly increasing, the exploitation of spectral features is a threat for camouflaged objects. To improve camouflage materials at first the spectral behavior of backgrounds has to be known to adjust and optimize the spectral reflectance of camouflage materials. In an international effort, the NATO CSO working group SCI-295 "Development of Methods for Measurements and Evaluation of Natural Background EO Signatures" is developing a method how this characterization of backgrounds has to be done. It is obvious that the spectral characterization of a background will be quite an effort. To compare and exchange data internationally the measurements will have to be done in a similar way. To test and further improve this method an international field trial has been performed in Storkow, Germany. In the following we present first impressions and lessons learned from this field campaign and describe the data that has been measured.

  3. Substitution dynamical systems spectral analysis

    CERN Document Server

    Queffélec, Martine

    2010-01-01

    This volume mainly deals with the dynamics of finitely valued sequences, and more specifically, of sequences generated by substitutions and automata. Those sequences demonstrate fairly simple combinatorical and arithmetical properties and naturally appear in various domains. As the title suggests, the aim of the initial version of this book was the spectral study of the associated dynamical systems: the first chapters consisted in a detailed introduction to the mathematical notions involved, and the description of the spectral invariants followed in the closing chapters. This approach, combined with new material added to the new edition, results in a nearly self-contained book on the subject. New tools - which have also proven helpful in other contexts - had to be developed for this study. Moreover, its findings can be concretely applied, the method providing an algorithm to exhibit the spectral measures and the spectral multiplicity, as is demonstrated in several examples. Beyond this advanced analysis, many...

  4. High order spectral volume and spectral difference methods on unstructured grids

    Science.gov (United States)

    Kannan, Ravishekar

    The spectral volume (SV) and the spectral difference (SD) methods were developed by Wang and Liu and their collaborators for conservation laws on unstructured grids. They were introduced to achieve high-order accuracy in an efficient manner. Recently, these methods were extended to three-dimensional systems and to the Navier Stokes equations. The simplicity and robustness of these methods have made them competitive against other higher order methods such as the discontinuous Galerkin and residual distribution methods. Although explicit TVD Runge-Kutta schemes for the temporal advancement are easy to implement, they suffer from small time step limited by the Courant-Friedrichs-Lewy (CFL) condition. When the polynomial order is high or when the grid is stretched due to complex geometries or boundary layers, the convergence rate of explicit schemes slows down rapidly. Solution strategies to remedy this problem include implicit methods and multigrid methods. A novel implicit lower-upper symmetric Gauss-Seidel (LU-SGS) relaxation method is employed as an iterative smoother. It is compared to the explicit TVD Runge-Kutta smoothers. For some p-multigrid calculations, combining implicit and explicit smoothers for different p-levels is also studied. The multigrid method considered is nonlinear and uses Full Approximation Scheme (FAS). An overall speed-up factor of up to 150 is obtained using a three-level p-multigrid LU-SGS approach in comparison with the single level explicit method for the Euler equations for the 3rd order SD method. A study of viscous flux formulations was carried out for the SV method. Three formulations were used to discretize the viscous fluxes: local discontinuous Galerkin (LDG), a penalty method and the 2nd method of Bassi and Rebay. Fourier analysis revealed some interesting advantages for the penalty method. These were implemented in the Navier Stokes solver. An implicit and p-multigrid method was also implemented for the above. An overall speed

  5. Camouflage in thermal IR: spectral design

    Science.gov (United States)

    Pohl, Anna; Fagerström, Jan; Kariis, Hans; Lindell, Roland; Hallberg, Tomas; Högström, Herman

    2016-10-01

    In this work a spectral designed coating from SPECTROGON is evaluated. Spectral design in this case means that the coating has a reflectivity equal to one at 3-5 and 8-12 microns were sensors operate and a much lower reflectivity in the other wave length regions. Three boxes are evaluated: one metallic, one black-body and one with a spectral designed surface, all with a 15 W radiator inside the box. It is shown that the box with the spectral designed surface can combine the two good characteristics of the other boxes: low signature from the metallic box and reasonable inside temperature from the black-body box. The measurements were verified with calculations using RadThermIR.

  6. Light distribution system comprising spectral conversion means

    DEFF Research Database (Denmark)

    2012-01-01

    , longer wavelength,a spectral conversion characteristics of the spectral conversion fibre being essentially determined by the spectral absorption and emission properties of the photoluminescent agent, the amount of photo- luminescent agent,and the distribution of the photoluminescent agent in the spectral......System (200, 300) for the distribution of white light, having a supply side (201, 301, 401) and a delivery side (202, 302, 402), the system being configured for guiding light with a multitude of visible wavelengths in a propagation direction P from the supply side to the distribution side...... of providing a light distribution system and a method of correcting the spectral transmission characteristics of a light distribution system are disclosed....

  7. Parametric Explosion Spectral Model

    Energy Technology Data Exchange (ETDEWEB)

    Ford, S R; Walter, W R

    2012-01-19

    Small underground nuclear explosions need to be confidently detected, identified, and characterized in regions of the world where they have never before occurred. We develop a parametric model of the nuclear explosion seismic source spectrum derived from regional phases that is compatible with earthquake-based geometrical spreading and attenuation. Earthquake spectra are fit with a generalized version of the Brune spectrum, which is a three-parameter model that describes the long-period level, corner-frequency, and spectral slope at high-frequencies. Explosion spectra can be fit with similar spectral models whose parameters are then correlated with near-source geology and containment conditions. We observe a correlation of high gas-porosity (low-strength) with increased spectral slope. The relationship between the parametric equations and the geologic and containment conditions will assist in our physical understanding of the nuclear explosion source.

  8. A rapid excitation-emission matrix fluorometer utilizing supercontinuum white light and acousto-optic tunable filters

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Wenbo [Imaging Unit, Integrative Oncology Department, BC Cancer Agency Research Center, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3 (Canada); Department of Dermatology and Skin Science, University of British Columbia, 835 West 10th Avenue, Vancouver, British Columbia V5Z 4E8 (Canada); Department of Biomedical Engineering, University of British Columbia, KAIS 5500, 2332 Main Mall, Vancouver, British Columbia V6T 1Z4 (Canada); Wu, Zhenguo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan, E-mail: hzeng@bccrc.ca [Imaging Unit, Integrative Oncology Department, BC Cancer Agency Research Center, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3 (Canada); Department of Dermatology and Skin Science, University of British Columbia, 835 West 10th Avenue, Vancouver, British Columbia V5Z 4E8 (Canada)

    2016-06-15

    Scanning speed and coupling efficiency of excitation light to optic fibres are two major technical challenges that limit the potential of fluorescence excitation-emission matrix (EEM) spectrometer for on-line applications and in vivo studies. In this paper, a novel EEM system, utilizing a supercontinuum white light source and acousto-optic tunable filters (AOTFs), was introduced and evaluated. The supercontinuum white light, generated by pumping a nonlinear photonic crystal fiber with an 800 nm femtosecond laser, was efficiently coupled into a bifurcated optic fiber bundle. High speed EEM spectral scanning was achieved using AOTFs both for selecting excitation wavelength and scanning emission spectra. Using calibration lamps (neon and mercury argon), wavelength deviations were determined to vary from 0.18 nm to −0.70 nm within the spectral range of 500–850 nm. Spectral bandwidth for filtered excitation light broadened by twofold compared to that measured with monochromatic light between 650 nm and 750 nm. The EEM spectra for methanol solutions of laser dyes were successfully acquired with this rapid fluorometer using an integration time of 5 s.

  9. A rapid excitation-emission matrix fluorometer utilizing supercontinuum white light and acousto-optic tunable filters

    International Nuclear Information System (INIS)

    Wang, Wenbo; Wu, Zhenguo; Zhao, Jianhua; Lui, Harvey; Zeng, Haishan

    2016-01-01

    Scanning speed and coupling efficiency of excitation light to optic fibres are two major technical challenges that limit the potential of fluorescence excitation-emission matrix (EEM) spectrometer for on-line applications and in vivo studies. In this paper, a novel EEM system, utilizing a supercontinuum white light source and acousto-optic tunable filters (AOTFs), was introduced and evaluated. The supercontinuum white light, generated by pumping a nonlinear photonic crystal fiber with an 800 nm femtosecond laser, was efficiently coupled into a bifurcated optic fiber bundle. High speed EEM spectral scanning was achieved using AOTFs both for selecting excitation wavelength and scanning emission spectra. Using calibration lamps (neon and mercury argon), wavelength deviations were determined to vary from 0.18 nm to −0.70 nm within the spectral range of 500–850 nm. Spectral bandwidth for filtered excitation light broadened by twofold compared to that measured with monochromatic light between 650 nm and 750 nm. The EEM spectra for methanol solutions of laser dyes were successfully acquired with this rapid fluorometer using an integration time of 5 s.

  10. Removal of garlic-like off-odours from crustacea by gamma irradiation

    International Nuclear Information System (INIS)

    Freeman, D.J.; Izzard, M.E.; Whitfield, F.B.

    1985-01-01

    The strong garlic-like off-odours associated with the male shovel-nosed lobster (Ibacus peronii) and the royal red prawn (Hymenopenaeus sibogae) have been attributed principally to the presence of the sulphur-containing compound bis-(methylthio)-methane. In the male shovel-nosed lobster the concentration of this compound increases very rapidly following death, and a small number of contaminated crustacea may cause an entire consignment to be condemned. A method for removing this noxious odour was developed which involved gamma-irradiation of the affected crustacea using a cobalt-60 source. Eight lobsters were subjected to gamma-irradiation at a dose rate of 10 kGy an hour; one half of each was given a dose of 25 kGy and the other half a dose of 5 kGy. Results showed that a high dose completely removes the existing off-odour, and also prevents its further formation. With the lower dose the off-odour is not completely removed. A trial using fresh royal red prawns at doses of 0.5 and 1.0 kGy showed irradiation removed all traces of the off-odour, but in those irradiated at the higher dose a slight burnt flavour was noticeable

  11. Removal of garlic-like off-odours from crustacea by gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, D J; Izzard, M E [Australian Atomic Energy Commission Research Establishment, Lucas Heights; Whitfield, F B [Commonwealth Scientific and Industrial Research Organization, North Ryde (Australia). Div. of Food Research

    1985-04-01

    The strong garlic-like off-odours associated with the male shovel-nosed lobster (Ibacus peronii) and the royal red prawn (Hymenopenaeus sibogae) have been attributed principally to the presence of the sulphur-containing compound bis-(methylthio)-methane. In the male shovel-nosed lobster the concentration of this compound increases very rapidly following death, and a small number of contaminated crustacea may cause an entire consignment to be condemned. A method for removing this noxious odour was developed which involved gamma-irradiation of the affected crustacea using a cobalt-60 source. Eight lobsters were subjected to gamma-irradiation at a dose rate of 10 kGy an hour; one half of each was given a dose of 25 kGy and the other half a dose of 5 kGy. Results showed that a high dose completely removes the existing off-odour, and also prevents its further formation. With the lower dose the off-odour is not completely removed. A trial using fresh royal red prawns at doses of 0.5 and 1.0 kGy showed irradiation removed all traces of the off-odour, but in those irradiated at the higher dose a slight burnt flavour was noticeable.

  12. [Modeling and Simulation of Spectral Polarimetric BRDF].

    Science.gov (United States)

    Ling, Jin-jiang; Li, Gang; Zhang, Ren-bin; Tang, Qian; Ye, Qiu

    2016-01-01

    Under the conditions of the polarized light, The reflective surface of the object is affected by many factors, refractive index, surface roughness, and so the angle of incidence. For the rough surface in the different wavelengths of light exhibit different reflection characteristics of polarization, a spectral polarimetric BRDF based on Kirchhof theory is proposee. The spectral model of complex refraction index is combined with refraction index and extinction coefficient spectral model which were got by using the known complex refraction index at different value. Then get the spectral model of surface roughness derived from the classical surface roughness measuring method combined with the Fresnel reflection function. Take the spectral model of refraction index and roughness into the BRDF model, then the spectral polarimetirc BRDF model is proposed. Compare the simulation results of the refractive index varies with wavelength, roughness is constant, the refraction index and roughness both vary with wavelength and origin model with other papers, it shows that, the spectral polarimetric BRDF model can show the polarization characteristics of the surface accurately, and can provide a reliable basis for the application of polarization remote sensing, and other aspects of the classification of substances.

  13. Removal of steroid estrogens from wastewater using granular activated carbon: comparison between virgin and reactivated carbon.

    Science.gov (United States)

    Rowsell, Victoria Francesca; Pang, Dawn Sok Cheng; Tsafou, Foteini; Voulvoulis, Nikolaos

    2009-04-01

    This research was set up in response to new European legislation to identify cost-effective treatment for removal of steroid estrogens from effluent. This study aimed to compare estrogen removal of two types of granular activated carbon: virgin (F400) and reactivated (C401) carbon. Rapid, small-scale column tests were conducted with a total bed volume of 24.9 cm3 over three columns, and analysis was carried out using high-performance liquid chromatography. Results demonstrated that C401 performed more efficiently with greater than or equal to 81% estrogen removal in wastewater compared to F400 which produced greater than or equal to 65% estrogen removal. Estrogen removal can be affected by competitive adsorption from natural organic matter present in wastewater. In addition, the physical properties of each carbon had the potential to influence adsorption differently, thus resulting in the observed varied adsorption capability of the two carbons.

  14. Rapid Erosion Modeling in a Western Kenya Watershed using Visible Near Infrared Reflectance, Classification Tree Analysis and 137Cesium.

    Science.gov (United States)

    deGraffenried, Jeff B; Shepherd, Keith D

    2009-12-15

    Human induced soil erosion has severe economic and environmental impacts throughout the world. It is more severe in the tropics than elsewhere and results in diminished food production and security. Kenya has limited arable land and 30 percent of the country experiences severe to very severe human induced soil degradation. The purpose of this research was to test visible near infrared diffuse reflectance spectroscopy (VNIR) as a tool for rapid assessment and benchmarking of soil condition and erosion severity class. The study was conducted in the Saiwa River watershed in the northern Rift Valley Province of western Kenya, a tropical highland area. Soil 137 Cs concentration was measured to validate spectrally derived erosion classes and establish the background levels for difference land use types. Results indicate VNIR could be used to accurately evaluate a large and diverse soil data set and predict soil erosion characteristics. Soil condition was spectrally assessed and modeled. Analysis of mean raw spectra indicated significant reflectance differences between soil erosion classes. The largest differences occurred between 1,350 and 1,950 nm with the largest separation occurring at 1,920 nm. Classification and Regression Tree (CART) analysis indicated that the spectral model had practical predictive success (72%) with Receiver Operating Characteristic (ROC) of 0.74. The change in 137 Cs concentrations supported the premise that VNIR is an effective tool for rapid screening of soil erosion condition.

  15. EEG spectral coherence data distinguish chronic fatigue syndrome patients from healthy controls and depressed patients--a case control study.

    Science.gov (United States)

    Duffy, Frank H; McAnulty, Gloria B; McCreary, Michelle C; Cuchural, George J; Komaroff, Anthony L

    2011-07-01

    Previous studies suggest central nervous system involvement in chronic fatigue syndrome (CFS), yet there are no established diagnostic criteria. CFS may be difficult to differentiate from clinical depression. The study's objective was to determine if spectral coherence, a computational derivative of spectral analysis of the electroencephalogram (EEG), could distinguish patients with CFS from healthy control subjects and not erroneously classify depressed patients as having CFS. This is a study, conducted in an academic medical center electroencephalography laboratory, of 632 subjects: 390 healthy normal controls, 70 patients with carefully defined CFS, 24 with major depression, and 148 with general fatigue. Aside from fatigue, all patients were medically healthy by history and examination. EEGs were obtained and spectral coherences calculated after extensive artifact removal. Principal Components Analysis identified coherence factors and corresponding factor loading patterns. Discriminant analysis determined whether spectral coherence factors could reliably discriminate CFS patients from healthy control subjects without misclassifying depression as CFS. Analysis of EEG coherence data from a large sample (n = 632) of patients and healthy controls identified 40 factors explaining 55.6% total variance. Factors showed highly significant group differentiation (p EEG spectral coherence analysis identified unmedicated patients with CFS and healthy control subjects without misclassifying depressed patients as CFS, providing evidence that CFS patients demonstrate brain physiology that is not observed in healthy normals or patients with major depression. Studies of new CFS patients and comparison groups are required to determine the possible clinical utility of this test. The results concur with other studies finding neurological abnormalities in CFS, and implicate temporal lobe involvement in CFS pathophysiology.

  16. Spectral Line Shapes in Plasmas and Gases

    International Nuclear Information System (INIS)

    Oks, E.; Dalimier, D.; Stamm, R.; Stehle, CH.; Gonzalez, M.A.

    2011-01-01

    The subject of spectral line shapes (SLS), a.k.a. spectral line broadening, which embraces both shapes and shifts of spectral lines, is of both fundamental and practical importance. On the fundamental side, the study of the spectral line profiles reveals the underlying atomic and molecular interactions. On the practical side, the spectral line profiles are employed as powerful diagnostic tools for various media, such as neutral gases, technological gas discharges, magnetically confined plasmas for fusion, laser- and Z-pinch-produced plasmas (for fusion and other purposes), astrophysical plasmas (most importantly, solar plasmas), and planetary atmospheres. The research area covered by this special issue includes both the SLS dominated by various electric fields (including electron and ion micro fields in strongly ionized plasmas) and the SLS controlled by neutral particles. In the physical slang, the former is called plasma broadening while the latter is called neutral broadening (of course, the results of neutral broadening apply also to the spectral line broadening in neutral gases)

  17. Photoinduced electron transfer and persistent spectral hole-burning in natural emerald.

    Science.gov (United States)

    Riesen, Hans

    2011-06-02

    Wavelength-selective excited-state lifetime measurements and absorption, luminescence, and hole-burning spectra of a natural African emerald crystal are reported. The (2)E excited-state lifetime displays an extreme wavelength dependence, varying from 190 to 37 μs within 1.8 nm of the R(1)-line. Overall, the excited state is strongly quenched, in comparison to laboratory-created emerald (τ=1.3 ms), with an average quenching rate of ∼6 × 10(3) s(-1) at 2.5 K. This quenching is attributed to photoinduced electron transfer caused by a relatively high concentration of Fe(2+) ions. The forward electron-transfer rate, k(f), from the nearest possible Fe(2+) sites at around 5 Å is estimated to be ∼20 × 10(3) s(-1) at 2.5 K. The photoreductive quenching of the excited Cr(3+) ions by Fe(2+) is followed by rapid electron back-transfer in the ground state upon deactivation. The exchange interaction based quenching can be modeled by assuming a random quencher distribution within the possible Fe(2+) sites with the forward electron-transfer rate, k(f), given as a function of acceptor-donor separation R by exp[(R(f)-R)/a(f)]; R(f) and a(f) values of 13.5 and 2.7 Å are obtained at 2.5 K. The electron transfer/back-transfer reorganizes the local crystal lattice, occasionally leading to a minor variation of the short-range structure around the Cr(3+) ions. This provides a mechanism for spectral hole-burning for which a moderately high quantum efficiency of about ∼0.005% is observed. Spectral holes are subject to spontaneous hole-filling and spectral diffusion, and both effects can be quantified within the standard two-level systems for non-photochemical hole-burning. Importantly, the absorbance increases on both sides of broad spectral holes, and isosbestic points are observed, in accord with the expected distribution of the "photoproduct" in a non-photochemical hole-burning process. © 2011 American Chemical Society

  18. Microbial community structure and a core microbiome in biological rapid sand filters at Danish waterworks

    DEFF Research Database (Denmark)

    Gülay, Arda; Musovic, Sanin; Albrechtsen, Hans-Jørgen

    Rapid sand filtration is a traditional and common technology for drinking water purification from groundwater. Despite its wide scale and long-term use, the diversity and characterization of microbial communities in these engineered systems have remained unexplored and their roles in removal perf...

  19. The influence of wavelength-dependent radiation in simulation of lamp-heated rapid thermal processing systems

    Energy Technology Data Exchange (ETDEWEB)

    Ting, A. [Sandia National Labs., Livermore, CA (United States). Computational Mechanics Dept.

    1994-08-01

    Understanding the thermal response of lamp-heated rapid thermal processing (RTP) systems requires understanding relatively complex radiation exchange among opaque and partially transmitting surfaces and materials. The objective of this paper is to investigate the influence of wavelength-dependent radiative properties. The examples used for the analysis consider axisymmetric systems of the kind that were developed by Texas Instruments (TI) for the Microelectronics Manufacturing Science and Technology (MMST) Program and illustrate a number of wavelength-dependent (spectral) effects. The models execute quickly on workstation class computing flatforms, and thus permit rapid comparison of alternative reactor designs and physical models. The fast execution may also permit the incorporation of these models into real-time model-based process control algorithms.

  20. SPECTRAL SMILE CORRECTION IN CRISM HYPERSPECTRAL IMAGES

    Science.gov (United States)

    Ceamanos, X.; Doute, S.

    2009-12-01

    The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is affected by a common artifact in "push-broom" sensors, the so-called "spectral smile". As a consequence, both central wavelength and spectral width of the spectral response vary along the across-track dimension, thus giving rise to a shifting and smoothing of spectra (see Fig. 1 (left)). In fact, both effects are greater for spectra on the edges, while they are minimum for data acquired by central detectors, the so-called "sweet spot". The prior artifacts become particularly critical for Martian observations which contain steep spectra such as CO2 ice-rich polar images. Fig. 1 (right) shows the horizontal brightness gradient which appears in every band corresponding to a steep portion of spectra. The correction of CRISM spectral smile is addressed using a two-step method which aims at modifying data sensibly in order to mimic the optimal CRISM response. First, all spectra, which are previously interpolated by cubic splines, are resampled to the "sweet spot" wavelengths in order to overcome the spectra shift. Secondly, the non-uniform spectral width is overcome by mimicking an increase of spectral resolution thanks to a spectral sharpening. In order to minimize noise, only bands particularly suffering from smile are selected. First, bands corresponding to the outliers of the Minimum Noise Transformation (MNF) eigenvector, which corresponds to the MNF band related to smile (MNF-smile), are selected. Then, a spectral neighborhood Θi, which takes into account the local spectral convexity or concavity, is defined for every selected band in order to maximize spectral shape preservation. The proposed sharpening technique takes into account both the instrument parameters and the observed spectra. First, every reflectance value belonging to a Θi is reevaluated by a sharpening which depends on a ratio of the spectral width of the current detector and the "sweet spot" one. Then, the optimal degree of

  1. A rapid method for monitoring the hydrodeoxygenation of coal-derived naphtha

    Energy Technology Data Exchange (ETDEWEB)

    Farnand, B.A.; Coulombe, S.; Smiley, G.T.; Fairbridge, C.

    1988-01-01

    A bonded polar poly(ethylene glycol) capillary column has been used for the identification and quantification of the phenolic components in synthetic crude naphthas. This provides a rapid and routine method for the determination of phenolic oxygen content with results comparable to combustion and neutron activation methods. The method is most useful in monitoring the removal of phenolic oxygen by hydroprocessing. 11 refs., 1 fig. 1 tab.

  2. Hair Removal

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Hair Removal KidsHealth / For Teens / Hair Removal What's in ... you need any of them? Different Types of Hair Before removing hair, it helps to know about ...

  3. Rapid prototyping of nanotube-based devices using topology-optimized microgrippers

    DEFF Research Database (Denmark)

    Sardan, Özlem; Eichhorn, Volkmar; Petersen, D.H.

    2008-01-01

    Nanorobotic handling of carbon nanotubes (CNTs) using microgrippers is one of the most promising approaches for the rapid characterization of the CNTs and also for the assembly of prototypic nanotube-based devices. In this paper, we present pick-and-place nanomanipulation of multi-walled CNTs...... in a rapid and a reproducible manner. We placed CNTs on copper TEM grids for structural analysis and on AFM probes for the assembly of AFM super-tips. We used electrothermally actuated polysilicon microgrippers designed using topology optimization in the experiments. The microgrippers are able to open...... with an amorphous carbon layer, which is locally removed at the contact points with the microgripper. The assembled AFM super-tips are used for AFM measurements of microstructures with high aspect ratios....

  4. X-ray stars observed in LAMOST spectral survey

    Science.gov (United States)

    Lu, Hong-peng; Zhang, Li-yun; Han, Xianming L.; Shi, Jianrong

    2018-05-01

    X-ray stars have been studied since the beginning of X-ray astronomy. Investigating and studying the chromospheric activity from X-ray stellar optical spectra is highly significant in providing insights into stellar magnetic activity. The big data of LAMOST survey provides an opportunity for researching stellar optical spectroscopic properties of X-ray stars. We inferred the physical properties of X-ray stellar sources from the analysis of LAMOST spectra. First, we cross-matched the X-ray stellar catalogue (12254 X-ray stars) from ARXA with LAMOST data release 3 (DR3), and obtained 984 good spectra from 713 X-ray sources. We then visually inspected and assigned spectral type to each spectrum and calculated the equivalent width (EW) of Hα line using the Hammer spectral typing facility. Based on the EW of Hα line, we found 203 spectra of 145 X-ray sources with Hα emission above the continuum. For these spectra we also measured the EWs of Hβ, Hγ, Hδ and Ca ii IRT lines of these spectra. After removing novae, planetary nebulae and OB-type stars, we found there are 127 X-ray late-type stars with Hα line emission. By using our spectra and results from the literature, we found 53 X-ray stars showing Hα variability; these objects are Classical T Tauri stars (CTTs), cataclysmic variables (CVs) or chromospheric activity stars. We also found 18 X-ray stars showing obvious emissions in the Ca ii IRT lines. Of the 18 X-ray stars, 16 are CTTs and 2 are CVs. Finally, we discussed the relationships between the EW of Hα line and X-ray flux.

  5. Buckling feedback of the spectral calculations

    International Nuclear Information System (INIS)

    Jing Xingqing; Shan Wenzhi; Luo Jingyu

    1992-01-01

    This paper studies the problems about buckling feedback of spectral calculations in physical calculations of the reactor and presents a useful method by which the buckling feedback of spectral calculations is implemented. The effect of the buckling feedback in spectra and the broad group cross section, convergence of buckling feedback iteration and the effect of the spectral zones dividing are discussed in the calculations. This method has been used for the physical design of HTR-10 MW Test Module

  6. Pollutant Removal, Dispersion and Entrainment over Two-Dimensional Idealized Street Canyons: an LES Approach

    Science.gov (United States)

    Wong, C.; Liu, C.

    2010-12-01

    Unlike pollutant transport over flat terrain, the mechanism and plume dispersion over urban areas is not well known. This study is therefore conceived to examine how urban morphology modifies the pollutant transport over urban areas. The computational domain and boundary condition used in this study is shown in Figure 1. The LES shows that inside the street canyon, the ground-level pollutants are carried to roof-level by the re-circulating flow, which are then removed from the street canyon to the UBL. Right above the roof level, narrow high-speed air masses in the streamwise flows and intensive downdrafts have been found in the shear layer. Different from the flows over a smooth surface, the maximum turbulence intensities descend that are peaked near the top of the building roughness. The pollutant is rather uniformly distributed inside a street canyon but disperses rapidly over the buildings exhibiting a Gaussian-plume form in the UBL. The mean component of vertical pollutant flux shows that the mean wind contributes to pollutant removal and entrainment simultaneously. Whereas, the fluctuating component demystifies that pollutant removal is mainly governed by atmospheric turbulence. Over the roof level, atmospheric flows slow down rapidly in the wake behind leeward building, suggesting the momentum entrainment into the street canyons. The decelerating streamwise flows in turn lead to upward flows carrying pollutants away from the street canyons, illustrating the basic pollutant removal mechanism in the skimming flow regime. Figure 1: Computational domain and boundary conditions Figure 2: Ensemble average vertical pollutant flux along the roof level. (a). Mean component; (b). turbulent component.

  7. Spectral Slope as an Indicator of Pasture Quality

    Directory of Open Access Journals (Sweden)

    Rachel Lugassi

    2014-12-01

    Full Text Available In this study, we develop a spectral method for assessment of pasture quality based only on the spectral information obtained with a small number of wavelengths. First, differences in spectral behavior were identified across the near infrared–shortwave infrared spectral range that were indicative of changes in chemical properties. Then, slopes across different spectral ranges were calculated and correlated with the changes in crude protein (CP, neutral detergent fiber (NDF and metabolic energy concentration (MEC. Finally, partial least squares (PLS regression analysis was applied to identify the optimal spectral ranges for accurate assessment of CP, NDF and MEC. Six spectral domains and a set of slope criteria for real-time evaluation of pasture quality were suggested. The evaluation of three level categories (low, medium, high for these three parameters showed a success rate of: 73%–96% for CP, 72%–87% for NDF and 60%–85% for MEC. Moreover, only one spectral range, 1748–1764 nm, was needed to provide a good estimation of CP, NDF and MEC. Importantly, five of the six selected spectral regions were not affected by water absorbance. With some modifications, this rationale can be applied to further analyses of pasture quality from airborne sensors.

  8. Monitoring urban greenness dynamics using multiple endmember spectral mixture analysis.

    Directory of Open Access Journals (Sweden)

    Muye Gan

    Full Text Available Urban greenness is increasingly recognized as an essential constituent of the urban environment and can provide a range of services and enhance residents' quality of life. Understanding the pattern of urban greenness and exploring its spatiotemporal dynamics would contribute valuable information for urban planning. In this paper, we investigated the pattern of urban greenness in Hangzhou, China, over the past two decades using time series Landsat-5 TM data obtained in 1990, 2002, and 2010. Multiple endmember spectral mixture analysis was used to derive vegetation cover fractions at the subpixel level. An RGB-vegetation fraction model, change intensity analysis and the concentric technique were integrated to reveal the detailed, spatial characteristics and the overall pattern of change in the vegetation cover fraction. Our results demonstrated the ability of multiple endmember spectral mixture analysis to accurately model the vegetation cover fraction in pixels despite the complex spectral confusion of different land cover types. The integration of multiple techniques revealed various changing patterns in urban greenness in this region. The overall vegetation cover has exhibited a drastic decrease over the past two decades, while no significant change occurred in the scenic spots that were studied. Meanwhile, a remarkable recovery of greenness was observed in the existing urban area. The increasing coverage of small green patches has played a vital role in the recovery of urban greenness. These changing patterns were more obvious during the period from 2002 to 2010 than from 1990 to 2002, and they revealed the combined effects of rapid urbanization and greening policies. This work demonstrates the usefulness of time series of vegetation cover fractions for conducting accurate and in-depth studies of the long-term trajectories of urban greenness to obtain meaningful information for sustainable urban development.

  9. Effect of CaCO3(S) nucleation modes on algae removal from alkaline water.

    Science.gov (United States)

    Choi, Jin Yong; Kinney, Kerry A; Katz, Lynn E

    2016-02-29

    The role of calcite heterogeneous nucleation was studied in a particle coagulation treatment process for removing microalgae from water. Batch experiments were conducted with Scenedesmus sp. and Chlorella sp. in the presence and absence of carbonate and in the presence and absence of Mg to delineate the role of CaCO 3(S) nucleation on microalgae removal. The results indicate that effective algae coagulation (e.g., up to 81 % algae removal efficiency) can be achieved via heterogeneous nucleation with CaCO 3(S) ; however, supersaturation ratios between 120 and 200 are required to achieve at least 50% algae removal, depending on ion concentrations. Algae removal was attributed to adsorption of Ca 2+ onto the cell surface which provides nucleation sites for CaCO 3(S) precipitation. Bridging of calcite particles between the algal cells led to rapid aggregation and formation of larger flocs. However, at higher supersaturation conditions, algae removal was diminished due to the dominance of homogeneous nucleation of CaCO 3(S) . Removal of algae in the presence of Ca 2+ and Mg 2+ required higher supersaturation values; however, the shift from heteronucleation to homonucleation with increasing supersaturation was still evident. The results suggest that water chemistry, pH, ionic strength, alkalinity and Ca 2+ concentration can be optimized for algae removal via coagulation-sedimentation.

  10. Rapid recurrence of a malignant meningioma: case report

    Directory of Open Access Journals (Sweden)

    Baran Oguz

    2017-06-01

    Full Text Available This short report presents a case that developed rapid recurrence of a malignant meningioma. The meningioma was located on the right temporal lobe and total removal (Simpson grade-II was performed. Radiotherapy was not given and the lesion recurred within four months. The MIB-1 (Ki-67 index was 30 % and the tumor fulfilled all the criteria of anaplasia. After the second surgery, patient was transferred to the Radiation Oncology for radiotherapy. Should we questioned the extent of surgery? Neurosurgeons should be careful and close follow-up the patients with malignant meningioma.

  11. Arsenic removal from acidic solutions with biogenic ferric precipitates

    Energy Technology Data Exchange (ETDEWEB)

    Ahoranta, Sarita H., E-mail: sarita.ahoranta@tut.fi [Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland); Kokko, Marika E., E-mail: marika.kokko@tut.fi [Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland); Papirio, Stefano, E-mail: stefano.papirio@unicas.it [Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland); Özkaya, Bestamin, E-mail: bozkaya@yildiz.edu.tr [Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland); Department of Environmental Engineering, Yildiz Technical University, Davutpasa Campus 34220, Esenler, Istanbul (Turkey); Puhakka, Jaakko A., E-mail: jaakko.puhakka@tut.fi [Department of Chemistry and Bioengineering, Tampere University of Technology, P.O. Box 541, FI-33101 Tampere (Finland)

    2016-04-05

    Highlights: • Continuous and rapid arsenic removal with biogenic jarosite was achieved at pH 3.0. • Arsenic removal was inefficient below pH 2.4 due to reduced Fe–As co-precipitation. • As(V) had better sorption characteristics than As(III). • Biogenic jarosite adsorbed arsenic more effectively than synthetic jarosite. - Abstract: Treatment of acidic solution containing 5 g/L of Fe(II) and 10 mg/L of As(III) was studied in a system consisting of a biological fluidized-bed reactor (FBR) for iron oxidation, and a gravity settler for iron precipitation and separation of the ferric precipitates. At pH 3.0 and FBR retention time of 5.7 h, 96–98% of the added Fe(II) precipitated (99.1% of which was jarosite). The highest iron oxidation and precipitation rates were 1070 and 28 mg/L/h, respectively, and were achieved at pH 3.0. Subsequently, the effect of pH on arsenic removal through sorption and/or co-precipitation was examined by gradually decreasing solution pH from 3.0 to 1.6 (feed pH). At pH 3.0, 2.4 and 1.6, the highest arsenic removal efficiencies obtained were 99.5%, 80.1% and 7.1%, respectively. As the system had ferric precipitates in excess, decreased arsenic removal was likely due to reduced co-precipitation at pH < 2.4. As(III) was partially oxidized to As(V) in the system. In shake flask experiments, As(V) sorbed onto jarosite better than As(III). Moreover, the sorption capacity of biogenic jarosite was significantly higher than that of synthetic jarosite. The developed bioprocess simultaneously and efficiently removes iron and arsenic from acidic solutions, indicating potential for mining wastewater treatment.

  12. Spectrally-Selective Photonic Structures for PV Applications

    Directory of Open Access Journals (Sweden)

    Benedikt Bläsi

    2010-01-01

    Full Text Available We review several examples of how spectrally-selective photonic structures may be used to improve solar cell systems. Firstly, we introduce different spectrally-selective structures that are based on interference effects. Examples shown include Rugate filter, edge filter and 3D photonic crystals such as artificial opals. In the second part, we discuss several examples of photovoltaic (PV concepts that utilize spectral selectivity such as fluorescence collectors, upconversion systems, spectrum splitting concepts and the intermediate reflector concept. The potential of spectrally selective filters in the context of solar cells is discussed.

  13. DEEP WIDEBAND SINGLE POINTINGS AND MOSAICS IN RADIO INTERFEROMETRY: HOW ACCURATELY DO WE RECONSTRUCT INTENSITIES AND SPECTRAL INDICES OF FAINT SOURCES?

    Energy Technology Data Exchange (ETDEWEB)

    Rau, U.; Bhatnagar, S.; Owen, F. N., E-mail: rurvashi@nrao.edu [National Radio Astronomy Observatory, Socorro, NM-87801 (United States)

    2016-11-01

    Many deep wideband wide-field radio interferometric surveys are being designed to accurately measure intensities, spectral indices, and polarization properties of faint source populations. In this paper, we compare various wideband imaging methods to evaluate the accuracy to which intensities and spectral indices of sources close to the confusion limit can be reconstructed. We simulated a wideband single-pointing (C-array, L-Band (1–2 GHz)) and 46-pointing mosaic (D-array, C-Band (4–8 GHz)) JVLA observation using a realistic brightness distribution ranging from 1 μ Jy to 100 mJy and time-, frequency-, polarization-, and direction-dependent instrumental effects. The main results from these comparisons are (a) errors in the reconstructed intensities and spectral indices are larger for weaker sources even in the absence of simulated noise, (b) errors are systematically lower for joint reconstruction methods (such as Multi-Term Multi-Frequency-Synthesis (MT-MFS)) along with A-Projection for accurate primary beam correction, and (c) use of MT-MFS for image reconstruction eliminates Clean-bias (which is present otherwise). Auxiliary tests include solutions for deficiencies of data partitioning methods (e.g., the use of masks to remove clean bias and hybrid methods to remove sidelobes from sources left un-deconvolved), the effect of sources not at pixel centers, and the consequences of various other numerical approximations within software implementations. This paper also demonstrates the level of detail at which such simulations must be done in order to reflect reality, enable one to systematically identify specific reasons for every trend that is observed, and to estimate scientifically defensible imaging performance metrics and the associated computational complexity of the algorithms/analysis procedures.

  14. Multi-Configuration Matched Spectral Filter Core, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — OPTRA proposes an open-architecture spectral gas sensor based on compressive sensing concepts employed for both spatial and spectral domains. Our matched spectral...

  15. Adinkras, Dessins, Origami, and Supersymmetry Spectral Triples

    OpenAIRE

    Marcolli, Matilde; Zolman, Nick

    2016-01-01

    We investigate the spectral geometry and spectral action functionals associated to 1D Supersymmetry Algebras, using the classification of these superalgebras in terms of Adinkra graphs and the construction of associated dessin d'enfant and origami curves. The resulting spectral action functionals are computed in terms of the Selberg (super) trace formula.

  16. Suppressed eye growth following diffuser removal from myopic birds is not due to increased dopamine release

    International Nuclear Information System (INIS)

    Morgan, I.; Boelen, M.; Megaw, P.; Miethke, P.

    2001-01-01

    Full text: Myopia can be induced in developing chickens by fitting a diffuser over the eye. If the diffuser is removed, the restoration of normal visual input results in rapid suppression of eye growth, with ultimate restoration of normal vision. We have investigated whether the suppression of eye growth after the removal of a diffuser from a myopic eye results from an increased rate of release of dopamine from the retina. Chickens were maintained on a 12:12 light-dark cycle, and were fitted with a diffuser from day 7 to day 21. After removal of the diffuser, the rate of dopamine release was then followed by measuring the kinetics of accumulation of DOPAC in the vitreous during the light phase. The rate of scleral glycosaminoglycan synthesis (SGS) was followed by measuring the rate of incorporation of 35 S-sulphate into scleral buttons incubated in vitro. At the end of the period of development of form-deprivation myopia,dopamine release rates were very low in the myopic eyes compared to those in the contralateral control eyes. In contrast, SGS rates were higher in the sclera from myopic eyes. After removal of the diffusers, the rate of SGS declined rapidly to below that in the control eyes within 72h. In contrast, dopamine release rates remained low for up to 10 days after removal of the occluders. These results show that there is a correlation between reduced dopamine release and increased SGS during the development of myopia, but that there is not a symmetrical relationship during the suppression of SGS following occluder removal. These results therefore suggest that dopamine is not a crucial signalling molecule in the visually mediated control of eye growth. Copyright (2001) Australian Neuroscience Society

  17. Rapid fabrication of large-area, corrosion-resistant superhydrophobic Mg alloy surfaces.

    Science.gov (United States)

    Xu, Wenji; Song, Jinlong; Sun, Jing; Lu, Yao; Yu, Ziyuan

    2011-11-01

    A superhydrophobic magnesium (Mg) alloy surface was successfully fabricated via a facile electrochemical machining process, and subsequently covered with a fluoroalkylsilane (FAS) film. The surface morphologies and chemical compositions were investigated using a scanning electron microscope (SEM) equipped with an energy-dispersive spectroscopy (EDS) and a Fourier-transform infrared spectrophotometer (FTIR). The results show hierarchal rough structures and an FAS film with a low surface energy on the Mg alloy surfaces, which confers good superhydrophobicity with a water contact angle of 165.2° and a water tilting angle of approximately 2°. The processing conditions, such as the processing time and removal rate per unit area at a constant removal mass per unit area, were investigated to determine their effects on the superhydrophobicity. Interestingly, when the removal mass per unit area is constant at approximately 11.10 mg/cm(2), the superhydrophobicity does not change with the removal rate per unit area. Therefore, a superhydrophobic Mg alloy surface can be rapidly fabricated based on this property. A large-area superhydrophobic Mg alloy surface was also fabricated for the first time using a small-area moving cathode. The corrosion resistance and durability of the superhydrophobic surfaces were also examined.

  18. The X-Shooter spectral library

    NARCIS (Netherlands)

    Chen, Y. P.; Trager, S. C.; Peletier, R. F.; Lançon, A.; Prugniel, Ph.; Koleva, M.

    2012-01-01

    We are building a new spectral library with the X-Shooter instrument on ESO's VLT: XSL, the X-Shooter Spectral Library. We present our progress in building XSL, which covers the wavelength range from the near-UV to the near-IR with a resolution of R˜10000. As of now we have collected spectra for

  19. A New Measurement of the Spectral Lag of Gamma-Ray Bursts and its Implications for Spectral Evolution Behaviors

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Lang; Wang, Fu-Ri; Cheng, Ye-Hao; Zhang, Xi; Yu, Bang-Yao; Xi, Bao-Jia; Wang, Xue; Feng, Huan-Xue; Zhang, Meng, E-mail: lshao@hebtu.edu.cn [Department of Space Sciences and Astronomy, Hebei Normal University, Shijiazhuang 050024 (China); Zhang, Bin-Bin [Instituto de Astrofísica de Andalucá (IAA-CSIC), P.O. Box 03004, E-18080 Granada (Spain); Wu, Xue-Feng [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Xu, Dong [Key Laboratory of Space Astronomy and Technology, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2017-08-01

    We carry out a systematical study of the spectral lag properties of 50 single-pulsed gamma-ray bursts (GRBs) detected by the Fermi Gamma-Ray Burst Monitor. By dividing the light curves into multiple consecutive energy channels, we provide a new measurement of the spectral lag that is independent of energy channel selections. We perform a detailed statistical study of our new measurements. We find two similar power-law energy dependencies of both the pulse arrival time and pulse width. Our new results on the power-law indices would favor the relativistic geometric effects for the origin of spectral lag. However, a complete theoretical framework that can fully account for the diverse energy dependencies of both arrival time and pulse width revealed in this work is still lacking. We also study the spectral evolution behaviors of the GRB pulses. We find that a GRB pulse with negligible spectral lag would usually have a shorter pulse duration and would appear to have a “hardness-intensity tracking” behavior, and a GRB pulse with a significant spectral lag would usually have a longer pulse duration and would appear to have a “hard-to-soft” behavior.

  20. Breast density estimation from high spectral and spatial resolution MRI

    Science.gov (United States)

    Li, Hui; Weiss, William A.; Medved, Milica; Abe, Hiroyuki; Newstead, Gillian M.; Karczmar, Gregory S.; Giger, Maryellen L.

    2016-01-01

    Abstract. A three-dimensional breast density estimation method is presented for high spectral and spatial resolution (HiSS) MR imaging. Twenty-two patients were recruited (under an Institutional Review Board--approved Health Insurance Portability and Accountability Act-compliant protocol) for high-risk breast cancer screening. Each patient received standard-of-care clinical digital x-ray mammograms and MR scans, as well as HiSS scans. The algorithm for breast density estimation includes breast mask generating, breast skin removal, and breast percentage density calculation. The inter- and intra-user variabilities of the HiSS-based density estimation were determined using correlation analysis and limits of agreement. Correlation analysis was also performed between the HiSS-based density estimation and radiologists’ breast imaging-reporting and data system (BI-RADS) density ratings. A correlation coefficient of 0.91 (pdensity estimations. An interclass correlation coefficient of 0.99 (pdensity estimations. A moderate correlation coefficient of 0.55 (p=0.0076) was observed between HiSS-based breast density estimations and radiologists’ BI-RADS. In summary, an objective density estimation method using HiSS spectral data from breast MRI was developed. The high reproducibility with low inter- and low intra-user variabilities shown in this preliminary study suggest that such a HiSS-based density metric may be potentially beneficial in programs requiring breast density such as in breast cancer risk assessment and monitoring effects of therapy. PMID:28042590

  1. Approximating spectral impact of structural perturbations in large networks

    CERN Document Server

    Milanese, A; Nishikawa, Takashi; Sun, Jie

    2010-01-01

    Determining the effect of structural perturbations on the eigenvalue spectra of networks is an important problem because the spectra characterize not only their topological structures, but also their dynamical behavior, such as synchronization and cascading processes on networks. Here we develop a theory for estimating the change of the largest eigenvalue of the adjacency matrix or the extreme eigenvalues of the graph Laplacian when small but arbitrary set of links are added or removed from the network. We demonstrate the effectiveness of our approximation schemes using both real and artificial networks, showing in particular that we can accurately obtain the spectral ranking of small subgraphs. We also propose a local iterative scheme which computes the relative ranking of a subgraph using only the connectivity information of its neighbors within a few links. Our results may not only contribute to our theoretical understanding of dynamical processes on networks, but also lead to practical applications in ran...

  2. Effectiveness of Rapid Cooling as a Method of Euthanasia for Young Zebrafish (Danio rerio).

    Science.gov (United States)

    Wallace, Chelsea K; Bright, Lauren A; Marx, James O; Andersen, Robert P; Mullins, Mary C; Carty, Anthony J

    2018-01-01

    Despite increased use of zebrafish (Danio rerio) in biomedical research, consistent information regarding appropriate euthanasia methods, particularly for embryos, is sparse. Current literature indicates that rapid cooling is an effective method of euthanasia for adult zebrafish, yet consistent guidelines regarding zebrafish younger than 6 mo are unavailable. This study was performed to distinguish the age at which rapid cooling is an effective method of euthanasia for zebrafish and the exposure times necessary to reliably euthanize zebrafish using this method. Zebrafish at 3, 4, 7, 14, 16, 19, 21, 28, 60, and 90 d postfertilization (dpf) were placed into an ice water bath for 5, 10, 30, 45, or 60 min (n = 12 to 40 per group). In addition, zebrafish were placed in ice water for 12 h (age ≤14 dpf) or 30 s (age ≥14 dpf). After rapid cooling, fish were transferred to a recovery tank and the number of fish alive at 1, 4, and 12-24 h after removal from ice water was documented. Euthanasia was defined as a failure when evidence of recovery was observed at any point after removal from ice water. Results showed that younger fish required prolonged exposure to rapid cooling for effective euthanasia, with the required exposure time decreasing as fish age. Although younger fish required long exposure times, animals became immobilized immediately upon exposure to the cold water, and behavioral indicators of pain or distress rarely occurred. We conclude that zebrafish 14 dpf and younger require as long as 12 h, those 16 to 28 dpf of age require 5 min, and those older than 28 dpf require 30 s minimal exposure to rapid cooling for reliable euthanasia.

  3. WE-DE-BRA-07: Megavoltage Spectral Imaging with a Layered Detector

    Energy Technology Data Exchange (ETDEWEB)

    Myronakis, M; Rottmann, J; Berbeco, R [Brigham and Women’s Hospital, Boston, MA (United States); Hu, Y [Dana Farber Cancer Institute, Boston, MA (United States); Wang, A; Shedlock, D; Star-Lack, J [Varian Medical Systems, Palo Alto, CA (United States); Morf, D [Varian Medical Systems, Dattwil, Aargau (Switzerland)

    2016-06-15

    Purpose: The aim of the current work is to investigate the feasibility of megavoltage spectral imaging using a multiple layered detector for enhancement of low contrast detectability through material segmentation and discrimination (such as bone, markers and metal implants). Potentially the technique can be applied to improve detection and reduce dose in Megavoltage Cone Beam Computed Tomography (MV-CBCT). Methods: Experiments were performed with a prototype multi-layer imager (MLI) which has higher detective efficiency and lower noise characteristics than conventional Electronic Portal Imaging Devices (EPIDs). Images of a solid water phantom were acquired at 2.5 MV, 6MV and 6MV without flattening filter (FFF). The following materials were placed within a stack of solid water: aluminum, copper and gold. Material separation was assessed based on Contrast-to-Noise Ratio (CNR) of the weighted image, formed by a weighted subtraction of the images from two layers of the MLI. A range of weighting factors were investigated for material separation. Results: CNR can be minimized for each material by appropriate selection of the subtraction weighting factor. This is equivalent to a selective subtraction of specific materials from the image. Using multiple layers simultaneously also decreases the dose requirement and removes any registration errors. The minimum CNR for aluminum, copper and gold at the weighted image formed with 2.5MV was obtained at weighting factors equal to 0.92, 0.76 and 0.64 respectively. The corresponding values at 6MVFFF were 0.99, 0.92 and 0.78 respectively. Conclusion: In the current work, an MV spectral imaging feasibility study was attempted using a novel multi-layer prototype EPID imager. Initial results suggest that material separation based on spectral differences between different layers is possible. This spectral imaging technique has potential advantages in MV-CBCT for real-time target tracking, patient set-up imaging and adaptive radiotherapy

  4. Learning theory of distributed spectral algorithms

    International Nuclear Information System (INIS)

    Guo, Zheng-Chu; Lin, Shao-Bo; Zhou, Ding-Xuan

    2017-01-01

    Spectral algorithms have been widely used and studied in learning theory and inverse problems. This paper is concerned with distributed spectral algorithms, for handling big data, based on a divide-and-conquer approach. We present a learning theory for these distributed kernel-based learning algorithms in a regression framework including nice error bounds and optimal minimax learning rates achieved by means of a novel integral operator approach and a second order decomposition of inverse operators. Our quantitative estimates are given in terms of regularity of the regression function, effective dimension of the reproducing kernel Hilbert space, and qualification of the filter function of the spectral algorithm. They do not need any eigenfunction or noise conditions and are better than the existing results even for the classical family of spectral algorithms. (paper)

  5. Management of impacted incisors following surgery to remove obstacles to eruption: a prospective clinical trial.

    Science.gov (United States)

    Pavoni, Chiara; Franchi, Lorenzo; Laganà, Giuseppina; Baccetti, Tiziano; Cozza, Paola

    2013-01-01

    The purpose of this study was to assess the effectiveness of rapid maxillary expansion (RME) vs simply monitoring the eruption of permanent maxillary incisors following the surgical removal of obstacles to their eruption (supernumerary teeth, odontomas). Following surgical removal of the obstacles to incisor eruption (T1), 62 patients were randomly assigned to either the group to undergo RME (34 subjects; mean age 8 years, 11 months ± 11 months) or the group that was monitored without further treatment (28 subjects; mean age=9 years, 1 month ± 1 year). At T2 (1 year after T1), the prevalence rate of erupted incisors was recorded. Also, the time of eruption of the incisors and the amount of space loss were analyzed. At T2, eruption of impacted incisors occurred in approximately 82 percent of the RME group cases vs approximately 39 percent of the monitored group cases (chi-square=10.43, P<.001). Time of eruption was significantly faster in the RME group, and anterior space loss significantly smaller. Rapid maxillary expansion treatment following surgical removal of the obstacles to the eruption of permanent maxillary incisors appears to be an efficient interceptive approach leading to eruption of the incisors in four out of five cases within seven months.

  6. The Open Spectral Database: an open platform for sharing and searching spectral data.

    Science.gov (United States)

    Chalk, Stuart J

    2016-01-01

    A number of websites make available spectral data for download (typically as JCAMP-DX text files) and one (ChemSpider) that also allows users to contribute spectral files. As a result, searching and retrieving such spectral data can be time consuming, and difficult to reuse if the data is compressed in the JCAMP-DX file. What is needed is a single resource that allows submission of JCAMP-DX files, export of the raw data in multiple formats, searching based on multiple chemical identifiers, and is open in terms of license and access. To address these issues a new online resource called the Open Spectral Database (OSDB) http://osdb.info/ has been developed and is now available. Built using open source tools, using open code (hosted on GitHub), providing open data, and open to community input about design and functionality, the OSDB is available for anyone to submit spectral data, making it searchable and available to the scientific community. This paper details the concept and coding, internal architecture, export formats, Representational State Transfer (REST) Application Programming Interface and options for submission of data. The OSDB website went live in November 2015. Concurrently, the GitHub repository was made available at https://github.com/stuchalk/OSDB/, and is open for collaborators to join the project, submit issues, and contribute code. The combination of a scripting environment (PHPStorm), a PHP Framework (CakePHP), a relational database (MySQL) and a code repository (GitHub) provides all the capabilities to easily develop REST based websites for ingestion, curation and exposure of open chemical data to the community at all levels. It is hoped this software stack (or equivalent ones in other scripting languages) will be leveraged to make more chemical data available for both humans and computers.

  7. SPECTRAL ANALYSIS OF EXCHANGE RATES

    Directory of Open Access Journals (Sweden)

    ALEŠA LOTRIČ DOLINAR

    2013-06-01

    Full Text Available Using spectral analysis is very common in technical areas but rather unusual in economics and finance, where ARIMA and GARCH modeling are much more in use. To show that spectral analysis can be useful in determining hidden periodic components for high-frequency finance data as well, we use the example of foreign exchange rates

  8. Removing an intersubject variance component in a general linear model improves multiway factoring of event-related spectral perturbations in group EEG studies.

    Science.gov (United States)

    Spence, Jeffrey S; Brier, Matthew R; Hart, John; Ferree, Thomas C

    2013-03-01

    Linear statistical models are used very effectively to assess task-related differences in EEG power spectral analyses. Mixed models, in particular, accommodate more than one variance component in a multisubject study, where many trials of each condition of interest are measured on each subject. Generally, intra- and intersubject variances are both important to determine correct standard errors for inference on functions of model parameters, but it is often assumed that intersubject variance is the most important consideration in a group study. In this article, we show that, under common assumptions, estimates of some functions of model parameters, including estimates of task-related differences, are properly tested relative to the intrasubject variance component only. A substantial gain in statistical power can arise from the proper separation of variance components when there is more than one source of variability. We first develop this result analytically, then show how it benefits a multiway factoring of spectral, spatial, and temporal components from EEG data acquired in a group of healthy subjects performing a well-studied response inhibition task. Copyright © 2011 Wiley Periodicals, Inc.

  9. Removal of choroidal neovascular membrane in a case of macular hole after anti-VEGF therapy for age-related macular degeneration.

    Science.gov (United States)

    Hirata, Akira; Hayashi, Ken; Murata, Kazuhisa; Nakamura, Kei-Ichiro

    2018-03-01

    The formation of macular hole after receiving anti-vascular endothelial growth factor (anti-VEGF) therapy is rare. We report a case of macular hole that occurred after intravitreal injection of an anti-VEGF agent for age-related macular degeneration (AMD) in a patient, who underwent vitrectomy combined with choroidal neovascularization (CNV) removal. A 64-year-old female with AMD affecting her right eye received an intravitreal injection of an anti-VEGF agent. After treatment, we identified a full thickness macular hole (MH) that was associated with the rapid resolution of the macular edema and contraction of the CNV. After performing vitrectomy combined with CNV removal, the MH closed and her visual acuity improved. Examination of the removed CNV revealed a network of microvessels devoid of pericytes. and Importance: The present findings suggest that rapid resolution of macular edema and contraction of the CNV and/or mild increase in the vitreous traction after anti-VEGF therapy could potentially cause MH. CNV removal via the MH may be an acceptable procedure, if the MH remains open, the CNV is of the classic type, and it spares a central portion of the fovea.

  10. [Analysis of H2S/PH3/NH3/AsH3/Cl2 by Full-Spectral Flame Photometric Detector].

    Science.gov (United States)

    Ding, Zhi-jun; Wang, Pu-hong; Li, Zhi-jun; Du, Bin; Guo, Lei; Yu, Jian-hua

    2015-07-01

    Flame photometric analysis technology has been proven to be a rapid and sensitive method for sulfur and phosphorus detection. It has been widely used in environmental inspections, pesticide detection, industrial and agricultural production. By improving the design of the traditional flame photometric detector, using grating and CCD sensor array as a photoelectric conversion device, the types of compounds that can be detected were expanded. Instead of a single point of characteristic spectral lines, full spectral information has been used for qualitative and quantitative analysis of H2S, PH3, NH3, AsH3 and Cl2. Combined with chemometric method, flame photometric analysis technology is expected to become an alternative fast, real-time on-site detection technology to simultaneously detect multiple toxic and harmful gases.

  11. Rapid identification and classification of Listeria spp. and serotype assignment of Listeria monocytogenes using fourier transform-infrared spectroscopy and artificial neural network analysis

    Science.gov (United States)

    The use of Fourier Transform-Infrared Spectroscopy (FT-IR) in conjunction with Artificial Neural Network software, NeuroDeveloper™ was examined for the rapid identification and classification of Listeria species and serotyping of Listeria monocytogenes. A spectral library was created for 245 strains...

  12. SPECTRAL SETS AND TILES IN CARTESIAN PRODUCTS OVER ...

    Indian Academy of Sciences (India)

    41

    Spectral set conjecture: A Borel set Ω ⊂ Rd of positive and finite. Lebesgue measure is a spectral set if and only if it ... Ω ⊂ G of positive and finite Haar measure is a spectral set if and only if it is a translational tile. ... Key words and phrases. p-adic number field, Cartesian product, tile, spectral set. This work was supported by ...

  13. Photovoltaic spectral responsivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Emery, K.; Dunlavy, D.; Field, H.; Moriarty, T. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    This paper discusses the various elemental random and nonrandom error sources in typical spectral responsivity measurement systems. The authors focus specifically on the filter and grating monochrometer-based spectral responsivity measurement systems used by the Photovoltaic (PV) performance characterization team at NREL. A variety of subtle measurement errors can occur that arise from a finite photo-current response time, bandwidth of the monochromatic light, waveform of the monochromatic light, and spatial uniformity of the monochromatic and bias lights; the errors depend on the light source, PV technology, and measurement system. The quantum efficiency can be a function of he voltage bias, light bias level, and, for some structures, the spectral content of the bias light or location on the PV device. This paper compares the advantages and problems associated with semiconductor-detector-based calibrations and pyroelectric-detector-based calibrations. Different current-to-voltage conversion and ac photo-current detection strategies employed at NREL are compared and contrasted.

  14. A combined spectral and object-based approach to transparent cloud removal in an operational setting for Landsat ETM+

    Science.gov (United States)

    Watmough, Gary R.; Atkinson, Peter M.; Hutton, Craig W.

    2011-04-01

    The automated cloud cover assessment (ACCA) algorithm has provided automated estimates of cloud cover for the Landsat ETM+ mission since 2001. However, due to the lack of a band around 1.375 μm, cloud edges and transparent clouds such as cirrus cannot be detected. Use of Landsat ETM+ imagery for terrestrial land analysis is further hampered by the relatively long revisit period due to a nadir only viewing sensor. In this study, the ACCA threshold parameters were altered to minimise omission errors in the cloud masks. Object-based analysis was used to reduce the commission errors from the extended cloud filters. The method resulted in the removal of optically thin cirrus cloud and cloud edges which are often missed by other methods in sub-tropical areas. Although not fully automated, the principles of the method developed here provide an opportunity for using otherwise sub-optimal or completely unusable Landsat ETM+ imagery for operational applications. Where specific images are required for particular research goals the method can be used to remove cloud and transparent cloud helping to reduce bias in subsequent land cover classifications.

  15. Doppler-Zeeman Mapping of the Rapidly Rotating Magnetic CP Star HD37776

    Science.gov (United States)

    Khokhlova, V. L.; Vasilchenko, D. V.; Stepanov, V. V.; Romanyuk, I. I.

    2000-03-01

    We present the results of our analysis of magnetic-field configuration and abundance anomalies on the surface of the rapidly rotating, chemically peculiar helium-strong variable B2 V star HD37776 with unresolved Zeeman components of spectral lines. Simultaneous inversion of the observed Stokes I and V profiles, which realizes the method of Doppler-Zeeman mapping (Vasilchenko et al. 1996), has been applied for the first time. Spectroscopic observations were carried out with the Main stellar spectrograph of the 6-m Special Astrophysical Observatory telescope equipped with a Zeeman analyzer and a CCD array, which allowed spectra in right- and left-hand circularly polarized light to be taken simultaneously at a signal-to-noise ratio S/N > 200 (Romanyuk et al. 1999). The profile width of winged spectral lines (reaching 5 A) is determined by Zeeman line splitting; however, the observed Zeeman components are blurred and unresolved because of the rapid stellar rotation. When solving the inverse problem, we sought for the magnetic-field configuration in the form of a combination of arbitrarily oriented dipole, quadrupole, and octupole placed at the stellar center. The observed Stokes I and V profiles for eight spectral lines of He, OII, AlIII, SiIII, and FeIII averaged over the visible stellar surface were used as input data. We constructed a model of the magnetic field from the condition of coincidence of magnetic maps obtained from different lines of different chemical elements and from the condition of a minimum profile residual. This model is a combination of centered coaxial dipole and quadrupole with the dominant quadrupole component at 30 deg < i < 50 deg, beta = 40 deg, and a maximum surface field strength H_s = 60 kG. A comparison of our abundance maps with the field configuration shows that the He concentration is at a maximum in the regions of maximum radial field, while the maximum concentrations of O, Al, Si, and Fe coincide with the regions of maximum

  16. 3D high spectral and spatial resolution imaging of ex vivo mouse brain

    International Nuclear Information System (INIS)

    Foxley, Sean; Karczmar, Gregory S.; Domowicz, Miriam; Schwartz, Nancy

    2015-01-01

    present at +7.0 Hz and may be specific to white matter anatomy. Moreover, a frequency shift of 6.76 ± 0.55 Hz was measured between the molecular and granular layers of the cerebellum. This shift is demonstrated in corresponding spectra; water peaks from voxels in the molecular and granular layers are consistently 2 bins apart (7.0 Hz, as dictated by the spectral resolution) from one another. Conclusions: High spectral and spatial resolution MR imaging has the potential to accurately measure the changes in the water resonance in small voxels. This information can guide optimization and interpretation of more commonly used, more rapid imaging methods that depend on image contrast produced by local susceptibility gradients. In addition, with improved sampling methods, high spectral and spatial resolution data could be acquired in reasonable run times, and used for in vivo scans to increase sensitivity to variations in local susceptibility

  17. Mapping invasive species and spectral mixture relationships with neotropical woody formations in southeastern Brazil

    Science.gov (United States)

    Amaral, Cibele H.; Roberts, Dar A.; Almeida, Teodoro I. R.; Souza Filho, Carlos R.

    2015-10-01

    Biological invasion substantially contributes to the increasing extinction rates of native vegetative species. The remote detection and mapping of invasive species is critical for environmental monitoring. This study aims to assess the performance of a Multiple Endmember Spectral Mixture Analysis (MESMA) applied to imaging spectroscopy data for mapping Dendrocalamus sp. (bamboo) and Pinus elliottii L. (slash pine), which are invasive plant species, in a Brazilian neotropical landscape within the tropical Brazilian savanna biome. The work also investigates the spectral mixture between these exotic species and the native woody formations, including woodland savanna, submontane and alluvial seasonal semideciduous forests (SSF). Visible to Shortwave Infrared (VSWIR) imaging spectroscopy data at one-meter spatial resolution were atmospherically corrected and subset into the different spectral ranges (VIS-NIR1: 530-919 nm; and NIR2-SWIR: 1141-2352 nm). The data were further normalized via continuum removal (CR). Multiple endmember selection methods, including Interactive Endmember Selection (IES), Endmember average root mean square error (EAR), Minimum average spectral angle (MASA) and Count-based (CoB) (collectively called EMC), were employed to create endmember libraries for the targeted vegetation classes. The performance of the MESMA was assessed at the pixel and crown scales. Statistically significant differences (α = 0.05) were observed between overall accuracies that were obtained at various spectral ranges. The infrared region (IR) was critical for detecting the vegetation classes using spectral data. The invasive species endmembers exhibited spectral patterns in the IR that were not observed in the native formations. Bamboo was characterized as having a high green vegetation (GV) fraction, lower non-photosynthetic vegetation (NPV) and a low shade fraction, while pine exhibited higher NPV and shade fractions. The invasive species showed a statistically

  18. Quantum entanglement: the unitary 8-vertex braid matrix with imaginary rapidity

    International Nuclear Information System (INIS)

    Chakrabarti, Amitabha; Chakraborti, Anirban; Jedidi, Aymen

    2010-01-01

    We study quantum entanglements induced on product states by the action of 8-vertex braid matrices, rendered unitary with purely imaginary spectral parameters (rapidity). The unitarity is displayed via the 'canonical factorization' of the coefficients of the projectors spanning the basis. This adds one more new facet to the famous and fascinating features of the 8-vertex model. The double periodicity and the analytic properties of the elliptic functions involved lead to a rich structure of the 3-tangle quantifying the entanglement. We thus explore the complex relationship between topological and quantum entanglement. (fast track communication)

  19. Spectral dimension of quantum geometries

    International Nuclear Information System (INIS)

    Calcagni, Gianluca; Oriti, Daniele; Thürigen, Johannes

    2014-01-01

    The spectral dimension is an indicator of geometry and topology of spacetime and a tool to compare the description of quantum geometry in various approaches to quantum gravity. This is possible because it can be defined not only on smooth geometries but also on discrete (e.g., simplicial) ones. In this paper, we consider the spectral dimension of quantum states of spatial geometry defined on combinatorial complexes endowed with additional algebraic data: the kinematical quantum states of loop quantum gravity (LQG). Preliminarily, the effects of topology and discreteness of classical discrete geometries are studied in a systematic manner. We look for states reproducing the spectral dimension of a classical space in the appropriate regime. We also test the hypothesis that in LQG, as in other approaches, there is a scale dependence of the spectral dimension, which runs from the topological dimension at large scales to a smaller one at short distances. While our results do not give any strong support to this hypothesis, we can however pinpoint when the topological dimension is reproduced by LQG quantum states. Overall, by exploring the interplay of combinatorial, topological and geometrical effects, and by considering various kinds of quantum states such as coherent states and their superpositions, we find that the spectral dimension of discrete quantum geometries is more sensitive to the underlying combinatorial structures than to the details of the additional data associated with them. (paper)

  20. Influence of spectral resolution, spectral range and signal-to-noise ratio of Fourier transform infra-red spectra on identification of high explosive substances

    Science.gov (United States)

    Banas, Krzysztof; Banas, Agnieszka M.; Heussler, Sascha P.; Breese, Mark B. H.

    2018-01-01

    In the contemporary spectroscopy there is a trend to record spectra with the highest possible spectral resolution. This is clearly justified if the spectral features in the spectrum are very narrow (for example infra-red spectra of gas samples). However there is a plethora of samples (in the liquid and especially in the solid form) where there is a natural spectral peak broadening due to collisions and proximity predominately. Additionally there is a number of portable devices (spectrometers) with inherently restricted spectral resolution, spectral range or both, which are extremely useful in some field applications (archaeology, agriculture, food industry, cultural heritage, forensic science). In this paper the investigation of the influence of spectral resolution, spectral range and signal-to-noise ratio on the identification of high explosive substances by applying multivariate statistical methods on the Fourier transform infra-red spectral data sets is studied. All mathematical procedures on spectral data for dimension reduction, clustering and validation were implemented within R open source environment.

  1. Extracting attosecond delays from spectrally overlapping interferograms

    Science.gov (United States)

    Jordan, Inga; Wörner, Hans Jakob

    2018-02-01

    Attosecond interferometry is becoming an increasingly popular technique for measuring the dynamics of photoionization in real time. Whereas early measurements focused on atomic systems with very simple photoelectron spectra, the technique is now being applied to more complex systems including isolated molecules and solids. The increase in complexity translates into an augmented spectral congestion, unavoidably resulting in spectral overlap in attosecond interferograms. Here, we discuss currently used methods for phase retrieval and introduce two new approaches for determining attosecond photoemission delays from spectrally overlapping photoelectron spectra. We show that the previously used technique, consisting in the spectral integration of the areas of interest, does in general not provide reliable results. Our methods resolve this problem, thereby opening the technique of attosecond interferometry to complex systems and fully exploiting its specific advantages in terms of spectral resolution compared to attosecond streaking.

  2. Salicylate removal by charcoal heamoperfusion in experimental intoxication in dogs. An assessment of efficacyd and safety

    Energy Technology Data Exchange (ETDEWEB)

    Brookings, C H [Saint George' s Hospital Medical School, London (UK). Dept. of Medicine; Ramsey, J D [Saint George' s Hospital Medical School, London (UK). Toxicology Lab.

    1975-11-01

    The removal of salicylate by extracorporeal circulation of blood through a column of encapsulated charcoal (haemoperfusion) has been studied experimentally in intoxicated dogs (greyhounds). The average time taken to reduce the whole blood salicylate level to one-half of the initial equilibrium level in 30 kg dogs was 2 hrs. A half-life of 3 hrs is predicted for salicylate removal by haemoperfusion in a 70 kg man and this rate of removal is shown to be comparable to that reported for haemodialysis. No unacceptable adverse physiological, biochemical, or haematological effects were found to result from haemoperfusion. The possible use of this technique in the management of severe salicylate poisoning in man is discussed. Haemoperfusion is foreseen as providing a method of rapid removal of salicylate in circumstances where forced diuresis is contra-indicated or inadequate and haemodialysis is not readily available.

  3. Impacts of invasive fish removal through angling on population characteristics and juvenile growth rate.

    Science.gov (United States)

    Evangelista, Charlotte; Britton, Robert J; Cucherousset, Julien

    2015-06-01

    Exploitation can modify the characteristics of fish populations through the selective harvesting of individuals, with this potentially leading to rapid ecological and evolutionary changes. Despite the well-known effects of invasive fishes on aquatic ecosystems generally, the potential effects of their selective removal through angling, a strategy commonly used to manage invasive fish, are poorly understood. The aim of this field-based study was to use the North American pumpkinseed Lepomis gibbosus as the model species to investigate the consequences of selective removal on their population characteristics and juvenile growth rates across 10 populations in artificial lakes in southern France. We found that the maximal individual mass in populations decreased as removal pressure through angling increased, whereas we did not observed any changes in the maximal individual length in populations as removal pressure increased. Total population abundance did not decrease as removal pressure increased; instead, here was a U-shaped relationship between removal pressure and the abundance of medium-bodied individuals. In addition, population biomass had a U-shaped curve response to removal pressure, implying that invasive fish populations can modulate their characteristics to compensate for the negative effects of selective removals. In addition, individual lengths at age 2 and juvenile growth rates decreased as removal pressure through angling increased, suggesting a shift toward an earlier size at maturity and an overall slower growing phenotype. Therefore, these outputs challenge the efficiency of selective management methods, suggesting the use of more proactive strategies to control invasive populations, and the need to investigate the potential ecological and evolutionary repercussions of nonrandom removal.

  4. Fission product aerosol removal test by containment spray under accident management conditions (3)

    International Nuclear Information System (INIS)

    Watanabe, Atsushi; Nagasaka, Hideo; Yokobori, Seiichi; Akinaga, Makoto

    2000-01-01

    In order to demonstrate the effective FP aerosol removal by containment spray under Japanese AM conditions, two system integral tests and two separate effect tests were carried out using a full-height simulation test facility. In case of PWR LOCA, aerosol concentration in the upper containment vessel decreased even under low spray flow rate. In case of BWR LOCA with water injection into RPV, the aerosol concentration in the entire vessel also decreased rapidly after aerosol supply stopping. In both cases, the removal rate estimated from the NUREG-1465 was coincided with test results. The aerosol washing effect by spray was confirmed to be predominant by conducting suppression chamber isolation test. It turned out that the effect of aerosol solubility and density on aerosol removal by spray was quite small by conducting insoluble aerosol injection test. After the modification of aerosol removal model by the spray and hygroscopic aerosol model in original MELCOR 1.8.4, calculated aerosol concentration transient in the containment vessel agreed well with the test data. (author)

  5. In vitro assessment of the effectiveness of whitening dentifrices for the removal of extrinsic tooth stains

    Directory of Open Access Journals (Sweden)

    Débora Alves Nunes Leite Lima

    2008-06-01

    Full Text Available This in vitro study evaluated the effectiveness of whitening dentifrices for the removal of extrinsic tooth stains. Twenty dental blocks (4 x 4 mm, including enamel and dentine, removed from freshly extracted bovine incisors, were randomly divided into 4 groups: G1 - distilled water, G2 - Colgate, G3 - Crest Extra Whitening and G4 - Rapid White. In all specimens, the dentin was covered with colorless nail polish, and the enamel was left exposed. Next, the specimens were immersed in a solution of black tea, which was changed every 24 h, for a period of 6 days. After this period, a photo-reflectance reading was taken (Time 1 with a spectrometer. The stained specimens were then submitted to linear brushing movements (5,000 cycles using brushes (Oral B-Soft coupled to an automatic toothbrushing machine, under a static axial load of 200 g and with a speed of 4 movements/second, at 37°C, with the dentifrice or water being injected every 60 s. When toothbrushing ended, a second photo-reflectance reading was taken (Time 2. The results were submitted to two-criteria analysis of variance (ANOVA and to the Tukey test ( = 0.05. When the two times for a same group were compared, Time 2 presented the highest reflectance values with statistical difference only for G3 and G4. Among the dentifrices tested, only the Rapid White group differed from the control group, presenting the highest reflectance values. Only the whitening dentifrice Rapid White was effective for the removal of extrinsic stains.

  6. Abundance estimation of spectrally similar minerals

    CSIR Research Space (South Africa)

    Debba, Pravesh

    2009-07-01

    Full Text Available This paper evaluates a spectral unmixing method for estimating the partial abundance of spectrally similar minerals in complex mixtures. The method requires formulation of a linear function of individual spectra of individual minerals. The first...

  7. Spectral mixture analysis for water quality assessment over the Amazon floodplain using Hyperion/EO-1 images

    Directory of Open Access Journals (Sweden)

    Lênio Soares Galvão

    2006-12-01

    Full Text Available Water composition undergoes complex spatial and temporal variations throughout the central Amazon floodplain. This study analyzed the spectral mixtures of the optically active substances (OASs in water with spaceborne hyperspectral images. The test site was located upstream the confluence of Amazon (white water and Tapajós (clear-water rivers, where two Hyperion images were acquired from the Earth Observing One (EO-1 satellite. The first image was acquired on September 16, 2001, during the falling water period of the Amazon River. The second image was acquired on June 23, 2005, at the end of the high water period. The images were pre-processed to remove stripes of anomalous pixels, convert radiance-calibrated data to surface reflectance, mask land, clouds and macrophytes targets, and spectral subset the data within the range of 457-885nm. A sequential procedure with the techniques Minimum Noise Fraction (MNF, Pixel Purity Index (PPI and n-dimensional visualization of the MNF feature space was employed to select end-members from both images. A single set of end-members was gathered to represent the following spectrally unique OASs: clear-water; dissolved organic matter; suspended sediments; and phytoplankton. The Linear Spectral Unmixing algorithm was applied to each Hyperion image in order to map the spatial distribution of these constituents, in terms of sub-pixel fractional abundances. Results showed three patterns of changes in the water quality from high to falling flood periods: decrease of suspended inorganic matter concentration in the Amazon River; increase of suspended inorganic matter and phytoplankton concentrations in varzea lakes; and increase of phytoplankton concentration in the Tapajós River.

  8. Spectral mixture analysis for water quality assessment over the Amazon floodplain using Hyperion/EO-1 images

    Directory of Open Access Journals (Sweden)

    Lênio Soares Galvão

    2007-06-01

    Full Text Available Water composition undergoes complex spatial and temporal variations throughout the central Amazon floodplain. This study analyzed the spectral mixtures of the optically active substances (OASs in water with spaceborne hyperspectral images. The test site was located upstream the confluence of Amazon (white water and Tapajós (clear-water rivers, where two Hyperion images were acquired from the Earth Observing One (EO-1 satellite. The first image was acquired on September 16, 2001, during the falling water period of the Amazon River. The second image was acquired on June 23, 2005, at the end of the high water period. The images were pre-processed to remove stripes of anomalous pixels, convert radiance-calibrated data to surface reflectance, mask land, clouds and macrophytes targets, and spectral subset the data within the range of 457-885nm. A sequential procedure with the techniques Minimum Noise Fraction (MNF, Pixel Purity Index (PPI and n-dimensional visualization of the MNF feature space was employed to select end-members from both images. A single set of end-members was gathered to represent the following spectrally unique OASs: clear-water; dissolved organic matter; suspended sediments; and phytoplankton. The Linear Spectral Unmixing algorithm was applied to each Hyperion image in order to map the spatial distribution of these constituents, in terms of sub-pixel fractional abundances. Results showed three patterns of changes in the water quality from high to falling flood periods: decrease of suspended inorganic matter concentration in the Amazon River; increase of suspended inorganic matter and phytoplankton concentrations in varzea lakes; and increase of phytoplankton concentration in the Tapajós River.

  9. Salinity and spectral reflectance of soils

    Science.gov (United States)

    Szilagyi, A.; Baumgardner, M. F.

    1991-01-01

    The basic spectral response related to the salt content of soils in the visible and reflective IR wavelengths is analyzed in order to explore remote sensing applications for monitoring processes of the earth system. The bidirectional reflectance factor (BRF) was determined at 10 nm of increments over the 520-2320-nm spectral range. The effect of salts on reflectance was analyzed on the basis of 162 spectral measurements. MSS and TM bands were simulated within the measured spectral region. A strong relationship was found in variations of reflectance and soil characteristics pertaining to salinization and desalinization. Although the individual MSS bands had high R-squared values and 75-79 percent of soil/treatment combinations were separable, there was a large number of soil/treatment combinations not distinguished by any of the four highly correlated MSS bands under consideration.

  10. Discovery and description of complete ammonium oxidizers in groundwater-fed rapid sand filters

    DEFF Research Database (Denmark)

    Palomo, Alejandro

    as biological filtration has long been acknowledged and recently been investigated. Biological filtration technology is widely used around the world and is especially important in Denmark as groundwater is the main source water for drinking water production. Because the groundwater has a relative high-quality......, aeration followed by biological filtration is the only required treatment before distribution. In the last years, the microbial communities in rapid gravity sand filters, the typical biological filter used in Denmark, have been characterized, but little knowledge had been required about their physiological...... activity and roles in compound removal from the source water. This PhD project focused on a comprehensive investigation of the microbial communities in rapid sand filters beyond their purely taxonomical identification. For this purpose, samples collected from a rapid sand filter were subjected...

  11. Strong correlation effects on the d-wave superconductor- spectral weight analysis by variational wave functions

    International Nuclear Information System (INIS)

    Chou, C-P; Lee, T K; Ho, C-M

    2009-01-01

    We examine the strong correlation effects of the d-wave superconducting state by including the Gutzwiller projection for no electron double occupancy at each lattice site. The spectral weights (SW's) for adding and removing an electron on the projected superconducting state, the ground state of the 2-dimensional t-t'-t - J model with moderate doped holes describing the high T c cuprates, are studied numerically on finite lattices and compared with the observation made by low-temperature tunneling (particle asymmetry of tunneling conductance) and angle-resolved photoemission (SW transfer from the projected Fermi liquid state) spectroscopies. The contrast with the d-wave case without projection is alo presented.

  12. Digital staining for histopathology multispectral images by the combined application of spectral enhancement and spectral transformation.

    Science.gov (United States)

    Bautista, Pinky A; Yagi, Yukako

    2011-01-01

    In this paper we introduced a digital staining method for histopathology images captured with an n-band multispectral camera. The method consisted of two major processes: enhancement of the original spectral transmittance and the transformation of the enhanced transmittance to its target spectral configuration. Enhancement is accomplished by shifting the original transmittance with the scaled difference between the original transmittance and the transmittance estimated with m dominant principal component (PC) vectors;the m-PC vectors were determined from the transmittance samples of the background image. Transformation of the enhanced transmittance to the target spectral configuration was done using an nxn transformation matrix, which was derived by applying a least square method to the enhanced and target spectral training data samples of the different tissue components. Experimental results on the digital conversion of a hematoxylin and eosin (H&E) stained multispectral image to its Masson's trichrome stained (MT) equivalent shows the viability of the method.

  13. Modeling the Performance of Biological Rapid Sand Filters Used to Remove Ammonium, Iron, and Manganese From Drinking Water

    DEFF Research Database (Denmark)

    Lee, Carson; Albrechtsen, Hans-Jørgen; Smets, Barth F.

    activated carbon and are often used following ozonation to remove additional biodegradable organics created during ozonation. In Europe, biological filters are also used to remove ammonium and reduced forms of iron and manganese. These compounds can cause biological instability in the distribution system...... tracer, are performed during an operational cycle of a filter to examine how the filter flow changes with time. The data is used to validate a mathematical model that can both predict process performance and to gain an understanding of how dynamic conditions can influence filter performance....... The mathematical model developed is intended to assist in the design of new filters, set up of pilot plant studies, and as a tool to troubleshoot existing problems in full scale filters. Unlike previous models, the model developed accounts for the effects of particle/precipitate accumulation and its effects...

  14. DNA microarray unravels rapid changes in transcriptome of MK-801 treated rat brain

    Science.gov (United States)

    Kobayashi, Yuka; Kulikova, Sofya P; Shibato, Junko; Rakwal, Randeep; Satoh, Hiroyuki; Pinault, Didier; Masuo, Yoshinori

    2015-01-01

    AIM: To investigate the impact of MK-801 on gene expression patterns genome wide in rat brain regions. METHODS: Rats were treated with an intraperitoneal injection of MK-801 [0.08 (low-dose) and 0.16 (high-dose) mg/kg] or NaCl (vehicle control). In a first series of experiment, the frontoparietal electrocorticogram was recorded 15 min before and 60 min after injection. In a second series of experiments, the whole brain of each animal was rapidly removed at 40 min post-injection, and different regions were separated: amygdala, cerebral cortex, hippocampus, hypothalamus, midbrain and ventral striatum on ice followed by DNA microarray (4 × 44 K whole rat genome chip) analysis. RESULTS: Spectral analysis revealed that a single systemic injection of MK-801 significantly and selectively augmented the power of baseline gamma frequency (30-80 Hz) oscillations in the frontoparietal electroencephalogram. DNA microarray analysis showed the largest number (up- and down- regulations) of gene expressions in the cerebral cortex (378), midbrain (376), hippocampus (375), ventral striatum (353), amygdala (301), and hypothalamus (201) under low-dose (0.08 mg/kg) of MK-801. Under high-dose (0.16 mg/kg), ventral striatum (811) showed the largest number of gene expression changes. Gene expression changes were functionally categorized to reveal expression of genes and function varies with each brain region. CONCLUSION: Acute MK-801 treatment increases synchrony of baseline gamma oscillations, and causes very early changes in gene expressions in six individual rat brain regions, a first report. PMID:26629322

  15. Semiconductor Laser Multi-Spectral Sensing and Imaging

    Directory of Open Access Journals (Sweden)

    Han Q. Le

    2010-01-01

    Full Text Available Multi-spectral laser imaging is a technique that can offer a combination of the laser capability of accurate spectral sensing with the desirable features of passive multispectral imaging. The technique can be used for detection, discrimination, and identification of objects by their spectral signature. This article describes and reviews the development and evaluation of semiconductor multi-spectral laser imaging systems. Although the method is certainly not specific to any laser technology, the use of semiconductor lasers is significant with respect to practicality and affordability. More relevantly, semiconductor lasers have their own characteristics; they offer excellent wavelength diversity but usually with modest power. Thus, system design and engineering issues are analyzed for approaches and trade-offs that can make the best use of semiconductor laser capabilities in multispectral imaging. A few systems were developed and the technique was tested and evaluated on a variety of natural and man-made objects. It was shown capable of high spectral resolution imaging which, unlike non-imaging point sensing, allows detecting and discriminating objects of interest even without a priori spectroscopic knowledge of the targets. Examples include material and chemical discrimination. It was also shown capable of dealing with the complexity of interpreting diffuse scattered spectral images and produced results that could otherwise be ambiguous with conventional imaging. Examples with glucose and spectral imaging of drug pills were discussed. Lastly, the technique was shown with conventional laser spectroscopy such as wavelength modulation spectroscopy to image a gas (CO. These results suggest the versatility and power of multi-spectral laser imaging, which can be practical with the use of semiconductor lasers.

  16. Semiconductor laser multi-spectral sensing and imaging.

    Science.gov (United States)

    Le, Han Q; Wang, Yang

    2010-01-01

    Multi-spectral laser imaging is a technique that can offer a combination of the laser capability of accurate spectral sensing with the desirable features of passive multispectral imaging. The technique can be used for detection, discrimination, and identification of objects by their spectral signature. This article describes and reviews the development and evaluation of semiconductor multi-spectral laser imaging systems. Although the method is certainly not specific to any laser technology, the use of semiconductor lasers is significant with respect to practicality and affordability. More relevantly, semiconductor lasers have their own characteristics; they offer excellent wavelength diversity but usually with modest power. Thus, system design and engineering issues are analyzed for approaches and trade-offs that can make the best use of semiconductor laser capabilities in multispectral imaging. A few systems were developed and the technique was tested and evaluated on a variety of natural and man-made objects. It was shown capable of high spectral resolution imaging which, unlike non-imaging point sensing, allows detecting and discriminating objects of interest even without a priori spectroscopic knowledge of the targets. Examples include material and chemical discrimination. It was also shown capable of dealing with the complexity of interpreting diffuse scattered spectral images and produced results that could otherwise be ambiguous with conventional imaging. Examples with glucose and spectral imaging of drug pills were discussed. Lastly, the technique was shown with conventional laser spectroscopy such as wavelength modulation spectroscopy to image a gas (CO). These results suggest the versatility and power of multi-spectral laser imaging, which can be practical with the use of semiconductor lasers.

  17. Millimetre spectral indices of transition disks and their relation to the cavity radius

    Science.gov (United States)

    Pinilla, P.; Benisty, M.; Birnstiel, T.; Ricci, L.; Isella, A.; Natta, A.; Dullemond, C. P.; Quiroga-Nuñez, L. H.; Henning, T.; Testi, L.

    2014-04-01

    Context. Transition disks are protoplanetary disks with inner depleted dust cavities that are excellent candidates for investigating the dust evolution when there is a pressure bump. A pressure bump at the outer edge of the cavity allows dust grains from the outer regions to stop their rapid inward migration towards the star and to efficiently grow to millimetre sizes. Dynamical interactions with planet(s) have been one of the most exciting theories to explain the clearing of the inner disk. Aims: We look for evidence of millimetre dust particles in transition disks by measuring their spectral index αmm with new and available photometric data. We investigate the influence of the size of the dust depleted cavity on the disk integrated millimetre spectral index. Methods: We present the 3-mm (100 GHz) photometric observations carried out with the Plateau de Bure Interferometer of four transition disks: LkHα 330, UX Tau A, LRLL 31, and LRLL 67. We used the available values of their fluxes at 345 GHz to calculate their spectral index, as well as the spectral index for a sample of twenty transition disks. We compared the observations with two kinds of models. In the first set of models, we considered coagulation and fragmentation of dust in a disk in which a cavity is formed by a massive planet located at different positions. The second set of models assumes disks with truncated inner parts at different radii and with power-law dust-size distributions, where the maximum size of grains is calculated considering turbulence as the source of destructive collisions. Results: We show that the integrated spectral index is higher for transition disks (TD) than for regular protoplanetary disks (PD) with mean values of bar{αmmTD} = 2.70 ± 0.13 and bar{αmmPD} = 2.20 ± 0.07 respectively. For transition disks, the probability that the measured spectral index is positively correlated with the cavity radius is 95%. High angular resolution imaging of transition disks is needed to

  18. Methodologies for rapid evaluation of seismic demand levels in nuclear power plant structures

    International Nuclear Information System (INIS)

    Manrique, M.; Asfura, A.; Mukhim, G.

    1990-01-01

    A methodology for rapid assessment of both acceleration spectral peak and 'zero period acceleration' (ZPA) values for virtually any major structure in a nuclear power plant is presented. The methodology is based on spectral peak and ZPA amplification factors, developed from regression analyses of an analytical database. The developed amplification factors are applied to the plant's design ground spectrum to obtain amplified response parameters. A practical application of the methodology is presented. This paper also presents a methodology for calculating acceleration response spectrum curves at any number of desired damping ratios directly from a single known damping ratio spectrum. The methodology presented is particularly useful and directly applicable to older vintage nuclear power plant facilities (i.e. such as those affected by USI A-46). The methodology is based on principles of random vibration theory. The methodology has been implemented in a computer program (SPECGEN). SPECGEN results are compared with results obtained from time history analyses. (orig.)

  19. Early rehabilitation of facial defects using interim removable prostheses: A clinical case report

    Directory of Open Access Journals (Sweden)

    Vivekanandhan Ramkumar

    2013-01-01

    Full Text Available Surgical resection of neoplasms or malformations of the face may result in defects that are not amenable to immediate surgical reconstruction. Such defects can have a severe adverse effect on patient perceptions of body image and self-esteem. In these cases, the use of an interim removable facial prosthesis can offer a rapid alternative treatment solution. The patient may then resume social interactions more comfortably while permitting easy access to the facial defect to observe tissue healing while awaiting definitive rehabilitation. This article presents a case report describing the use of interim nasal prostheses to provide rapid patient rehabilitation of facial defects.

  20. The efficacy of selective calculus ablation at 400 nm: comparison to conventional calculus removal methods

    Science.gov (United States)

    Schoenly, Joshua E.; Seka, Wolf; Romanos, Georgios; Rechmann, Peter

    A desired outcome of scaling and root planing is the complete removal of calculus and infected root tissue and preservation of healthy cementum for rapid healing of periodontal tissues. Conventional periodontal treatments for calculus removal, such as hand instrument scaling and ultrasonic scaling, often deeply scrape the surface of the underlying hard tissue and may leave behind a smear layer. Pulsed lasers emitting at violet wavelengths (specifically, 380 to 400 nm) are a potential alternative treatment since they can selectively ablate dental calculus without ablating pristine hard tissue (i.e., enamel, cementum, and dentin). In this study, light and scanning electron microscopy are used to compare and contrast the efficacy of in vitro calculus removal for several conventional periodontal treatments (hand instruments, ultrasonic scaler, and Er:YAG laser) to calculus removal with a frequency-doubled Ti:sapphire (λ = 400 nm). After calculus removal, enamel and cementum surfaces are investigated for calculus debris and damage to the underlying hard tissue surface. Compared to the smear layer, grooves, and unintentional hard tissue removal typically found using these conventional treatments, calculus removal using the 400-nm laser is complete and selective without any removal of pristine dental hard tissue. Based on these results, selective ablation from the 400-nm laser appears to produce a root surface that would be more suitable for successful healing of periodontal tissues.

  1. A SIMPLE AND RAPID MATRIX-ASSISTED LASER DESORPTION/IONIZATION TIME OF FLIGHT MASS SPECTROMETRY METHOD TO SCREEN FISH PLASMA SAMPLES FOR ESTROGEN-RESPONSIVE BIOMARKERS

    Science.gov (United States)

    In this study, we describe and evaluate the performance of a simple and rapid mass spectral method for screening fish plasma for estrogen-responsive biomarkers using matrix assisted laster desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) couopled with a short...

  2. Spectral Imaging of Portolan Charts

    Science.gov (United States)

    France, Fenella G.; Wilson, Meghan A.; Ghez, Anita

    2018-05-01

    Spectral imaging of Portolan Charts, early nautical charts, provided extensive new information about their construction and creation. The origins of the portolan chart style have been a continual source of perplexity to numerous generations of cartographic historians. The spectral imaging system utilized incorporates a 50 megapixel mono-chrome camera with light emitting diode (LED) illumination panels that cover the range from 365 nm to 1050 nm to capture visible and non-visible information. There is little known about how portolan charts evolved, and what influenced their creation. These early nautical charts began as working navigational tools of medieval mariners, initially made in the 1300s in Italy, Portugal and Spain; however the origin and development of the portolan chart remained shrouded in mystery. Questions about these early navigational charts included whether colorants were commensurate with the time period and geographical location, and if different, did that give insight into trade routes, or possible later additions to the charts? For example; spectral data showed the red pigment on both the 1320 portolan chart and the 1565 Galapagos Islands matched vermillion, an opaque red pigment used since antiquity. The construction of these charts was also of great interest. Spectral imaging with a range of illumination modes revealed the presence of a "hidden circle" often referred to in relation to their construction. This paper will present in-depth analysis of how spectral imaging of the Portolans revealed similarities and differences, new hidden information and shed new light on construction and composition.

  3. Computer-assisted spectral design and synthesis

    Science.gov (United States)

    Vadakkumpadan, Fijoy; Wang, Qiqi; Sun, Yinlong

    2005-01-01

    In this paper, we propose a computer-assisted approach for spectral design and synthesis. This approach starts with some initial spectrum, modifies it interactively, evaluates the change, and decides the optimal spectrum. Given a requested change as function of wavelength, we model the change function using a Gaussian function. When there is the metameric constraint, from the Gaussian function of request change, we propose a method to generate the change function such that the result spectrum has the same color as the initial spectrum. We have tested the proposed method with different initial spectra and change functions, and implemented an interactive graphics environment for spectral design and synthesis. The proposed approach and graphics implementation for spectral design and synthesis can be helpful for a number of applications such as lighting of building interiors, textile coloration, and pigment development of automobile paints, and spectral computer graphics.

  4. Intermediate spectral theory and quantum dynamics

    CERN Document Server

    de Oliveira, Cesar R

    2008-01-01

    The spectral theory of linear operators plays a key role in the mathematical formulation of quantum theory. Furthermore, such a rigorous mathematical foundation leads to a more profound insight into the nature of quantum mechanics. This textbook provides a concise and comprehensible introduction to the spectral theory of (unbounded) self-adjoint operators and its application in quantum dynamics. The book places emphasis on the symbiotic relationship of these two domains by (1) presenting the basic mathematics of nonrelativistic quantum mechanics of one particle, i.e., developing the spectral theory of self-adjoint operators in infinite-dimensional Hilbert spaces from the beginning, and (2) giving an overview of many of the basic functional aspects of quantum theory, from its physical principles to the mathematical models. The book is intended for graduate (or advanced undergraduate) students and researchers interested in mathematical physics. It starts with linear operator theory, spectral questions and self-...

  5. Diclofenac removal in urine using strong-base anion exchange polymer resins.

    Science.gov (United States)

    Landry, Kelly A; Boyer, Treavor H

    2013-11-01

    One of the major sources of pharmaceuticals in the environment is wastewater effluent of which human urine contributes the majority of pharmaceuticals. Urine source separation has the potential to isolate pharmaceuticals at a higher concentration for efficient removal as well as produce a nutrient byproduct. This research investigated the efficacy of using strong-base anion exchange polymer resins to remove the widely detected and abundant pharmaceutical, diclofenac, from synthetic human urine under fresh and ureolyzed conditions. The majority of experiments were conducted using a strong-base, macroporous, polystyrene resin (Purolite A520E). Ion-exchange followed a two-step removal rate with rapid removal in 1 h and equilibrium removal in 24 h. Diclofenac removal was >90% at a resin dose of 8 mL/L in both fresh and ureolyzed urine. Sorption of diclofenac onto A520E resin was concurrent with desorption of an equivalent amount of chloride, which indicates the ion-exchange mechanism is occurring. The presence of competing ions such as phosphate and citrate did not significantly impact diclofenac removal. Comparisons of three polystyrene resins (A520E, Dowex 22, Dowex Marathon 11) as well as one polyacrylic resin (IRA958) were conducted to determine the major interactions between anion exchange resin and diclofenac. The results showed that polystyrene resins provide the highest level of diclofenac removal due to electrostatic interactions between quaternary ammonium functional groups of resin and carboxylic acid of diclofenac and non-electrostatic interactions between resin matrix and benzene rings of diclofenac. Diclofenac was effectively desorbed from A520E resin using a regeneration solution that contained 4.5% (m/m) NaCl in an equal-volume mixture of methanol and water. The greater regeneration efficiency of the NaCl/methanol-water mixture over the aqueous NaCl solution supports the importance of non-electrostatic interactions between resin matrix and benzene rings

  6. Spectral Estimation of UV-Vis Absorbance Time Series for Water Quality Monitoring

    Directory of Open Access Journals (Sweden)

    Leonardo Plazas-Nossa

    2017-05-01

    Full Text Available Context: Signals recorded as multivariate time series by UV-Vis absorbance captors installed in urban sewer systems, can be non-stationary, yielding complications in the analysis of water quality monitoring. This work proposes to perform spectral estimation using the Box-Cox transformation and differentiation in order to obtain stationary multivariate time series in a wide sense. Additionally, Principal Component Analysis (PCA is applied to reduce their dimensionality. Method: Three different UV-Vis absorbance time series for different Colombian locations were studied: (i El-Salitre Wastewater Treatment Plant (WWTP in Bogotá; (ii Gibraltar Pumping Station (GPS in Bogotá; and (iii San-Fernando WWTP in Itagüí. Each UV-Vis absorbance time series had equal sample number (5705. The esti-mation of the spectral power density is obtained using the average of modified periodograms with rectangular window and an overlap of 50%, with the 20 most important harmonics from the Discrete Fourier Transform (DFT and Inverse Fast Fourier Transform (IFFT. Results: Absorbance time series dimensionality reduction using PCA, resulted in 6, 8 and 7 principal components for each study site respectively, altogether explaining more than 97% of their variability. Values of differences below 30% for the UV range were obtained for the three study sites, while for the visible range the maximum differences obtained were: (i 35% for El-Salitre WWTP; (ii 61% for GPS; and (iii 75% for San-Fernando WWTP. Conclusions: The Box-Cox transformation and the differentiation process applied to the UV-Vis absorbance time series for the study sites (El-Salitre, GPS and San-Fernando, allowed to reduce variance and to eliminate ten-dency of the time series. A pre-processing of UV-Vis absorbance time series is recommended to detect and remove outliers and then apply the proposed process for spectral estimation. Language: Spanish.

  7. Rapid Radiochemical Analyses in Support of Fukushima Nuclear Accident - 13196

    Energy Technology Data Exchange (ETDEWEB)

    Maxwell, Sherrod L.; Culligan, Brian K.; Hutchison, Jay B. [Savannah River National Laboratory, Building 735-B, Aiken, SC 29808 (United States)

    2013-07-01

    precipitations, followed by Sr-Resin separation and gas flow proportional counting. To achieve a lower detection limit for analysis of some of the Japanese soil samples, a 10 gram aliquot of soil was taken, acid-leached and processed with similar preconcentration chemistry. The MDA using this approach was ∼0.03 pCi/g (1.1 mBq/g)/, which is less than the 0.05-0.10 pCi/g {sup 90}Sr levels found in soil as a result of global fallout. The chemical yields observed for the Japanese soil samples was typically 75-80% and the laboratory control sample (LCS) and matrix spike (MS) results looked very good for this work Individual QC results were well within the ± 25% acceptable range and the average of these results does not show significant bias. Additional data for a radiostrontium in soil method for 50 gram samples will also be presented, which appears to be a significant step forward based on looking at the current literature, with higher chemical yields for even larger sample aliquots and lower MDA [5, 6, 7] Hou et al surveyed a wide range of separation methods for Pu in waters and environmental solid samples [8]. While there are many actinide methods in the scientific literature, few would be considered rapid due to the tedious and time-consuming steps involved. For actinide analyses in soil, a new rapid method for the determination of actinide isotopes in soil samples using both alpha spectrometry and inductively-coupled plasma mass spectrometry was employed. The new rapid soil method utilizes an acid leaching method, iron/titanium hydroxide precipitation, a lanthanum fluoride soil matrix removal step, and a rapid column separation process with TEVA Resin. The large soil matrix is removed easily and rapidly using these two simple precipitations with high chemical recoveries and effective removal of interferences. [9, 10] Vacuum box technology and rapid flow rates were used to reduce analytical time. Challenges associated with the mineral content in the volcanic soil will be

  8. Removal of selected pollutants from aqueous media by hardwood mulch

    International Nuclear Information System (INIS)

    Ray, Asim B.; Selvakumar, Ariamalar; Tafuri, Anthony N.

    2006-01-01

    Generic hardwood mulch, usually used for landscaping, was utilized to remove several selected pollutants (heavy metals and toxic organic compounds) typically found in urban stormwater (SW) runoff. The hardwood mulch sorbed all the selected pollutants from a spiked stormwater mixture, including copper (Cu 2+ ), cadmium (Cd 2+ ), chromium (Cr 6+ ), lead (Pb 2+ ), zinc (Zn 2+ ), 1,3 dichlorobenzene (DCB), naphthalene (NP), fluoranthene (FA), butylbenzylphthalate (BBP), and benzo(a)pyrene (B[a]P). Masses of the pollutants sorbed depended upon the pollutant species, contact time, and initial concentration which varied from 20 to 100%. Sorption rates of the metals, in general, were more rapid than those of the organics; however, mass removals (percent) of the organics, in contrast to those of the metals, were independent of their initial concentrations. With the exception of Cd, percentages (weight) of the metals removed declined as their initial concentrations decreased. None of the sorbed pollutants desorbed to any significant extent upon extended washing with water. It is quite feasible that in the presence of mulch the uptake of these pollutants by the aquatic species will be reduced significantly

  9. Accurate and independent spectral response scale based on silicon trap detectors and spectrally invariant detectors

    International Nuclear Information System (INIS)

    Gran, Jarle

    2005-01-01

    The study aims to establish an independent high accuracy spectral response scale over a broad spectral range based on standard laboratory equipment at a moderate cost. This had to be done by a primary method, where the responsivity of the detector is linked to fundamental constants. Summary, conclusion and future directions: In this thesis it has been demonstrated that an independent spectral response scale from the visual to the IR based on simple relative measurements can be established. The accuracy obtained by the hybrid self-calibration method demonstrates that state of the art accuracy is obtained with self-calibration principles. A calculable silicon trap detector with low internal losses over a wide spectral range is needed to establish the scale, in addition to a linear, spectrally independent detector with a good signal to noise ratio. By fitting the parameters in the responsivity model to a purely relative measurement we express the spectral response in terms of fundamental constants with a known uncertainty This is therefore a primary method. By applying a digital filter on the relative measurements of the InGaAs detectors in the infrared reduces the standard deviation by 30 %. In addition, by optimising the necessary scaling constant converting the relative calibration to absolute values, we have managed to establish an accurate and cost efficient spectral response scale in the IR. The full covariance analysis, which takes into account the correlation in the absolute values of the silicon detector, the correlation caused by the filter and the scaling constant, shows that the spectral response scale established in the infrared with InGaAs detectors is done with high accuracy. A similar procedure can be used in the UV, though it has not been demonstrated here. In fig. 10 the responsitivities of the detectors (a) and their associated uncertainties (b) at the 1 sigma level of confidence is compared for the three publications. We see that the responsivity

  10. Integrated nitrogen removal biofilter system with ceramic membrane for advanced post-treatment of municipal wastewater.

    Science.gov (United States)

    Son, Dong-Jin; Yun, Chan-Young; Kim, Woo-Yeol; Zhang, Xing-Ya; Kim, Dae-Gun; Chang, Duk; Sunwoo, Young; Hong, Ki-Ho

    2016-12-01

    The pre-denitrification biofilm process for nitrogen removal was combined with ceramic membrane with pore sizes of 0.05-0.1 µm as a system for advanced post-treatment of municipal wastewater. The system was operated under an empty bed hydraulic retention time of 7.8 h, recirculation ratio of 3, and transmembrane pressure of 0.47 bar. The system showed average removals of organics, total nitrogen, and solids as high as 93%, 80%, and 100%, respectively. Rapid nitrification could be achieved and denitrification was performed in the anoxic filter without external carbon supplements. The residual particulate organics and nitrogen in effluent from biofilm process could be also removed successfully through membrane filtration and the removal of total coliform was noticeably improved after membrane filtration. Thus, a system composed of the pre-denitrification biofilm process with ceramic membrane would be a compact and flexible option for advanced post-treatment of municipal wastewater.

  11. Separate photosensitizers mediate degradation of the 32-kDa photosystem II reaction center protein in the visible and UV spectral regions

    International Nuclear Information System (INIS)

    Greenberg, B.M.; Gaba, V.; Canaani, O.; Malkin, S.; Mattoo, A.K.; Edelman, M.

    1989-01-01

    A component of the photosystem II reaction center, the 32-kDa protein, is rapidly turned over in the light. The mechanism of its light-dependent metabolism is largely unknown. We quantified the rate of 32-kDa protein degradation over a broad spectral range (UV, visible, and far red). The quantum yield for degradation was highest in the UVB (280-320 nm) region. Spectral evidence demonstrates two distinctly different photosensitizers for 32-kDa protein degradation. The data implicate the bulk photosynthetic pigments (primarily chlorophyll) in the visible and far red regions, and plastoquinone (in one or more of its redox states) in the UV region. A significant portion of 32-kDa protein degradation in sunlight is attributed to UVB irradiance

  12. Removal of Foodborne Pathogen Biofilms by Acidic Electrolyzed Water

    Directory of Open Access Journals (Sweden)

    Qiao Han

    2017-06-01

    Full Text Available Biofilms, which are complex microbial communities embedded in the protective extracellular polymeric substances (EPS, are difficult to remove in food production facilities. In this study, the use of acidic electrolyzed water (AEW to remove foodborne pathogen biofilms was evaluated. We used a green fluorescent protein-tagged Escherichia coli for monitoring the efficiency of AEW for removing biofilms, where under the optimal treatment conditions, the fluorescent signal of cells in the biofilm disappeared rapidly and the population of biofilm cells was reduced by more than 67%. Additionally, AEW triggered EPS disruption, as indicated by the deformation of the carbohydrate C-O-C bond and deformation of the aromatic rings in the amino acids tyrosine and phenylalanine. These deformations were identified by EPS chemical analysis and Raman spectroscopic analysis. Scanning electron microscopy (SEM images confirmed that the breakup and detachment of biofilm were enhanced after AEW treatment. Further, AEW also eradicated biofilms formed by both Gram-negative bacteria (Vibrio parahaemolyticus and Gram-positive bacteria (Listeria monocytogenes and was observed to inactivate the detached cells which are a potential source of secondary pollution. This study demonstrates that AEW could be a reliable foodborne pathogen biofilm disrupter and an eco-friendly alternative to sanitizers traditionally used in the food industry.

  13. Orientation dependence of temporal and spectral properties of high-order harmonics in solids

    Science.gov (United States)

    Wu, Mengxi; You, Yongsing; Ghimire, Shambhu; Reis, David A.; Browne, Dana A.; Schafer, Kenneth J.; Gaarde, Mette B.

    2017-12-01

    We investigate the connection between crystal symmetry and temporal and spectral properties of high-order harmonics in solids. We calculate the orientation-dependent harmonic spectrum driven by an intense, linearly polarized infrared laser field, using a momentum-space description of the generation process in terms of strong-field-driven electron dynamics on the band structure. We show that the orientation dependence of both the spectral yield and the subcycle time profile of the harmonic radiation can be understood in terms of the coupling strengths and relative curvatures of the valence band and the low-lying conduction bands. In particular, we show that in some systems this gives rise to a rapid shift of a quarter optical cycle in the timing of harmonics in the secondary plateau as the crystal is rotated relative to the laser polarization. We address recent experimental results in MgO [Y. S. You et al., Nat. Phys. 13, 345 (2017)., 10.1038/nphys3955] and show that the observed change in orientation dependence for the highest harmonics can be interpreted in the momentum space picture in terms of the contributions of several different conduction bands.

  14. Emissivity compensated spectral pyrometry—algorithm and sensitivity analysis

    International Nuclear Information System (INIS)

    Hagqvist, Petter; Sikström, Fredrik; Christiansson, Anna-Karin; Lennartson, Bengt

    2014-01-01

    In order to solve the problem of non-contact temperature measurements on an object with varying emissivity, a new method is herein described and evaluated. The method uses spectral radiance measurements and converts them to temperature readings. It proves to be resilient towards changes in spectral emissivity and tolerates noisy spectral measurements. It is based on an assumption of smooth changes in emissivity and uses historical values of spectral emissivity and temperature for estimating current spectral emissivity. The algorithm, its constituent steps and accompanying parameters are described and discussed. A thorough sensitivity analysis of the method is carried out through simulations. No rigorous instrument calibration is needed for the presented method and it is therefore industrially tractable. (paper)

  15. Effects of spectral smearing on performance of the spectral ripple and spectro-temporal ripple tests.

    Science.gov (United States)

    Narne, Vijaya Kumar; Sharma, Mridula; Van Dun, Bram; Bansal, Shalini; Prabhu, Latika; Moore, Brian C J

    2016-12-01

    The main aim of this study was to use spectral smearing to evaluate the efficacy of a spectral ripple test (SRt) using stationary sounds and a recent variant with gliding ripples called the spectro-temporal ripple test (STRt) in measuring reduced spectral resolution. In experiment 1 the highest detectable ripple density was measured using four amounts of spectral smearing (unsmeared, mild, moderate, and severe). The thresholds worsened with increasing smearing and were similar for the SRt and the STRt across the three conditions with smearing. For unsmeared stimuli, thresholds were significantly higher (better) for the STRt than for the SRt. An amplitude fluctuation at the outputs of simulated (gammatone) auditory filters centered above 6400 Hz was identified as providing a potential detection cue for the STRt stimuli. Experiment 2 used notched noise with energy below and above the passband of the SRt and STRt stimuli to reduce confounding cues in the STRt. Thresholds were almost identical for the STRt and SRt for both unsmeared and smeared stimuli, indicating that the confounding cue for the STRt was eliminated by the notched noise. Thresholds obtained with notched noise present could be predicted reasonably accurately using an excitation-pattern model.

  16. Removal of lead and fluoride from contaminated water using exhausted coffee grounds based bio-sorbent.

    Science.gov (United States)

    Naga Babu, A; Reddy, D Srinivasa; Kumar, G Suresh; Ravindhranath, K; Krishna Mohan, G V

    2018-07-15

    Water pollution by industrial and anthropogenic actives has become a serious threat to the environment. World Health Organization (WHO) has identified that lead and fluoride amid the environmental pollutants are most poisonous water contaminants with devastating impact on the human race. The present work proposes a study on economical bio-adsorbent based technique using exhausted coffee grounds in the removal of lead and fluoride contaminants from water. The exhausted coffee grounds gathered from industrial wastes have been acid-activated and examined for their adsorption capacity. The surface morphology and elemental characterization of pre-and-post adsorption operations by FESEM, EDX and FTIR spectral analysis confirmed the potential of the exhausted coffee ground as successful bio-sorbent. However, thermodynamic analysis confirmed the adsorption to be spontaneous physisorption with Langmuir mode of homogenous monolayer deposition. The kinetics of adsorption is well defined by pseudo second order model for both lead and fluoride. A significant quantity of lead and fluoride is removed from the synthetic contaminated water by the proposed bio-sorbent with the respective sorption capabilities of 61.6 mg/g and 9.05 mg/g. However, the developed bio-sorbent is also recyclable and is capable of removing the lead and fluoride from the domestic and industrial waste-water sources with an overall removal efficiency of about 90%. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Spectral Compressive Sensing with Polar Interpolation

    DEFF Research Database (Denmark)

    Fyhn, Karsten; Dadkhahi, Hamid; F. Duarte, Marco

    2013-01-01

    . In this paper, we introduce a greedy recovery algorithm that leverages a band-exclusion function and a polar interpolation function to address these two issues in spectral compressive sensing. Our algorithm is geared towards line spectral estimation from compressive measurements and outperforms most existing...

  18. Spectral induced polarization for monitoring electrokinetic remediation processes

    Science.gov (United States)

    Masi, Matteo; Losito, Gabriella

    2015-12-01

    Electrokinetic remediation is an emerging technology for extracting heavy metals from contaminated soils and sediments. This method uses a direct or alternating electric field to induce the transport of contaminants toward the electrodes. The electric field also produces pH variations, sorption/desorption and precipitation/dissolution of species in the porous medium during remediation. Since heavy metal mobility is pH-dependent, the accurate control of pH inside the material is required in order to enhance the removal efficiency. The common approach for monitoring the remediation process both in laboratory and in the field is the chemical analysis of samples collected from discrete locations. The purpose of this study is the evaluation of Spectral Induced Polarization as an alternative method for monitoring geochemical changes in the contaminated mass during remediation. The advantage of this technique applied to field-scale is to offer higher resolution mapping of the remediation site and lower cost compared to the conventional sampling procedure. We carried out laboratory-scale electrokinetic remediation experiments on fine-grained marine sediments contaminated by heavy metal and we made Spectral Induced Polarization measurements before and after each treatment. Measurements were done in the frequency range 10- 3-103 Hz. By the deconvolution of the spectra using the Debye Decomposition method we obtained the mean relaxation time and total chargeability. The main finding of this work is that a linear relationship exists between the local total chargeability and pH, with good agreement. The observed behaviour of chargeability is interpreted as a direct consequence of the alteration of the zeta potential of the sediment particles due to pH changes. Such relationship has a significant value for the interpretation of induced polarization data, allowing the use of this technique for monitoring electrokinetic remediation at field-scale.

  19. Maximum spectral demands in the near-fault region

    Science.gov (United States)

    Huang, Yin-Nan; Whittaker, Andrew S.; Luco, Nicolas

    2008-01-01

    The Next Generation Attenuation (NGA) relationships for shallow crustal earthquakes in the western United States predict a rotated geometric mean of horizontal spectral demand, termed GMRotI50, and not maximum spectral demand. Differences between strike-normal, strike-parallel, geometric-mean, and maximum spectral demands in the near-fault region are investigated using 147 pairs of records selected from the NGA strong motion database. The selected records are for earthquakes with moment magnitude greater than 6.5 and for closest site-to-fault distance less than 15 km. Ratios of maximum spectral demand to NGA-predicted GMRotI50 for each pair of ground motions are presented. The ratio shows a clear dependence on period and the Somerville directivity parameters. Maximum demands can substantially exceed NGA-predicted GMRotI50 demands in the near-fault region, which has significant implications for seismic design, seismic performance assessment, and the next-generation seismic design maps. Strike-normal spectral demands are a significantly unconservative surrogate for maximum spectral demands for closest distance greater than 3 to 5 km. Scale factors that transform NGA-predicted GMRotI50 to a maximum spectral demand in the near-fault region are proposed.

  20. Particulate removal processes and hydraulics of porous gravel media filters

    Science.gov (United States)

    Minto, J. M.; Phoenix, V. R.; Dorea, C. C.; Haynes, H.; Sloan, W. T.

    2013-12-01

    Sustainable urban Drainage Systems (SuDS) are rapidly gaining acceptance as a low-cost tool for treating urban runoff pollutants close to source. Road runoff water in particular requires treatment due to the presence of high levels of suspended particles and heavy metals adsorbed to these particles. The aim of this research is to elucidate the particle removal processes that occur within gravel filters that have so far been considered as 'black-box' systems. Based on these findings, a better understanding will be attained on what influences gravel filter removal efficiency and how this changes throughout their design life; leading to a more rational design of this useful technology. This has been achieved by tying together three disparate research elements: tracer residence time distribution curves of filters during clogging; 3D magnetic resonance imaging (MRI) of clogging filters and computational fluid dynamics (CFD) modelling of complex filter pore networks. This research relates column average changes in particle removal efficiency and tracer residence time distributions (RTDs) due to clogging with non-invasive measurement of the spatial variability in particle deposition. The CFD modelling provides a link between observed deposition patterns, flow velocities and wall shear stresses as well as the explanations for the change in RTD with clogging and the effect on particle transport. Results show that, as a filter clogs, particles take a longer, more tortuous path through the filter. This is offset by a reduction in filter volume resulting in higher flow velocities and more rapid particle transport. Higher velocities result in higher shear stresses and the development of preferential pathways in which the velocity exceeds the deposition threshold and the overall efficiency of the filter decreases. Initial pore geometry is linked to the pattern of deposition and subsequent formation of preferential pathways. These results shed light on the 'black-box' internal

  1. Spectral State Evolution of 4U 1820-30: the Stability of the Spectral Index of Comptonization Tail

    Science.gov (United States)

    Titarchuk, Lev G.; Seifina, Elena; Frontera, Filippo

    2013-01-01

    We analyze the X-ray spectra and their timing properties of the compact Xray binary 4U 1820-30. We establish spectral transitions in this source seen with BeppoSAX and the Rossi X-ray Timing Explorer (RXTE). During the RXTE observations (1996 - 2009), the source were approximately approximately 75% of its time in the soft state making the lower banana and upper banana transitions combined with long-term low-high state transitions. We reveal that all of the X-ray spectra of 4U 1820-30 are fit by a composition of a thermal (blackbody) component, a Comptonization component (COMPTB) and a Gaussian-line component. Thus using this spectral analysis we find that the photon power-law index Gamma of the Comptonization component is almost unchangeable (Gamma approximately 2) while the electron temperature kTe changes from 2.9 to 21 keV during these spectral events. We also establish that for these spectral events the normalization of COMPTB component (which is proportional to mass accretion rate ?M) increases by factor 8 when kTe decreases from 21 keV to 2.9 keV. Before this index stability effect was also found analyzing X-ray data for Z-source GX 340+0 and for atolls, 4U 1728-34, GX 3+1. Thus, we can suggest that this spectral stability property is a spectral signature of an accreting neutron star source. On the other hand in a black hole binary G monotonically increases with ?Mand ultimately its value saturates at large ?M.

  2. Removal of heavy metal from industrial effluents using Baker's yeast

    Science.gov (United States)

    Ferdous, Anika; Maisha, Nuzhat; Sultana, Nayer; Ahmed, Shoeb

    2016-07-01

    Bioremediation of wastewater containing heavy metals is one of the major challenges in environmental biotechnology. Heavy metals are not degraded and as a result they remain in the ecosystem, and pose serious health hazards as it comes in contact with human due to anthropogenic activities. Biological treatment with various microorganisms has been practiced widely in recent past, however, accessing and maintaining the microorganisms have always been a challenge. Microorganisms like Baker's yeast can be very promising biosorbents as they offer high surface to volume ratio, large availability, rapid kinetics of adsorption and desorption and low cost. The main aim of this study is to evaluate the applicability of the biosorption process using baker's yeast. Here we present an experimental investigation of biosorption of Chromium (Cr) from water using commercial Baker's Yeast. It was envisaged that yeast, dead or alive, would adsorb heavy metals, however, operating parameters could play vital roles in determining the removal efficiency. Parameters, such as incubation time, pH, amount of biosorbent and heavy metal concentration were varied to investigate the impacts of those parameters on removal efficiency. Rate of removal was found to be inversely proportional to the initial Cr (+6) concentrations but the removal rate per unit biomass was a weakly dependent on initial Cr(+6) concentrations. Biosorption process was found to be more efficient at lower pH and it exhibited lower removal with the increase in solution pH. The optimum incubation time was found to be between 6-8 hours and optimum pH for the metal ion solution was 2. The effluents produced in leather industries are the major source of chromium pollution in Bangladesh and this study has presented a very cost effective yet efficient heavy metal removal approach that can be adopted for such kind of wastewater.

  3. Total spectral distributions from Hawking radiation

    Energy Technology Data Exchange (ETDEWEB)

    Broda, Boguslaw [University of Lodz, Department of Theoretical Physics, Faculty of Physics and Applied Informatics, Lodz (Poland)

    2017-11-15

    Taking into account the time dependence of the Hawking temperature and finite evaporation time of the black hole, the total spectral distributions of the radiant energy and of the number of particles have been explicitly calculated and compared to their temporary (initial) blackbody counterparts (spectral exitances). (orig.)

  4. Spectral zone selection methodology for pebble bed reactors

    International Nuclear Information System (INIS)

    Mphahlele, Ramatsemela; Ougouag, Abderrafi M.; Ivanov, Kostadin N.; Gougar, Hans D.

    2011-01-01

    A methodology is developed for determining boundaries of spectral zones for pebble bed reactors. A spectral zone is defined as a region made up of a number of nodes whose characteristics are collectively similar and that are assigned the same few-group diffusion constants. The spectral zones are selected in such a manner that the difference (error) between the reference transport solution and the diffusion code solution takes a minimum value. This is achieved by choosing spectral zones through optimally minimizing this error. The objective function for the optimization algorithm is the total reaction rate error, which is defined as the sum of the leakage, absorption and fission reaction rates errors in each zone. The selection of these spectral zones is such that the core calculation results based on diffusion theory are within an acceptable tolerance as compared to a proper transport reference solution. Through this work, a consistent approach for identifying spectral zones that yield more accurate diffusion results is introduced.

  5. Spectral analysis and filter theory in applied geophysics

    CERN Document Server

    Buttkus, Burkhard

    2000-01-01

    This book is intended to be an introduction to the fundamentals and methods of spectral analysis and filter theory and their appli­ cations in geophysics. The principles and theoretical basis of the various methods are described, their efficiency and effectiveness eval­ uated, and instructions provided for their practical application. Be­ sides the conventional methods, newer methods arediscussed, such as the spectral analysis ofrandom processes by fitting models to the ob­ served data, maximum-entropy spectral analysis and maximum-like­ lihood spectral analysis, the Wiener and Kalman filtering methods, homomorphic deconvolution, and adaptive methods for nonstation­ ary processes. Multidimensional spectral analysis and filtering, as well as multichannel filters, are given extensive treatment. The book provides a survey of the state-of-the-art of spectral analysis and fil­ ter theory. The importance and possibilities ofspectral analysis and filter theory in geophysics for data acquisition, processing an...

  6. Rapid high temperature field test method for evaluation of geothermal calcite scale inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, R.G.

    1982-08-01

    A test method is described which allows the rapid field testing of calcite scale inhibitors in high- temperature geothermal brines. Five commercial formulations, chosen on the basis of laboratory screening tests, were tested in brines with low total dissolved solids at ca 500 F. Four were found to be effective; of these, 2 were found to be capable of removing recently deposited scale. One chemical was tested in the full-flow brine line for 6 wks. It was shown to stop a severe surface scaling problem at the well's control valve, thus proving the viability of the rapid test method. (12 refs.)

  7. Tritium removal by CO2 laser heating

    International Nuclear Information System (INIS)

    Skinner, C.H.; Kugel, H.; Mueller, D.

    1997-01-01

    Efficient techniques for rapid tritium removal will be necessary for ITER to meet its physics and engineering goals. One potential technique is transient surface heating by a scanning CO 2 or Nd:Yag laser that would release tritium without the severe engineering difficulties of bulk heating of the vessel. The authors have modeled the heat propagation into a surface layer and find that a multi-kW/cm 2 flux with an exposure time of order 10 ms is suitable to heat a 50 micron co-deposited layer to 1,000--2,000 degrees. Improved wall conditioning may be a significant side benefit. They identify remaining issues that need to be addressed experimentally

  8. Tritium removal by CO2 laser heating

    International Nuclear Information System (INIS)

    Skinner, C.H.; Kugel, H.; Mueller, D.

    1997-10-01

    Efficient techniques for rapid tritium removal will be necessary for ITER (International Thermonuclear Experimental Reactor) to meet its physics and engineering goals. One potential technique is transient surface heating by a scanning CO 2 or Nd:YAG laser that would release tritium without the severe engineering difficulties of bulk heating of the vessel. The authors have modeled the heat propagation into a surface layer and find that a multi-kW/cm 2 flux with an exposure time of order 10 msec is suitable to heat a 50 micron co-deposited layer to 1,000--2,000 degrees. Improved wall conditioning may be a significant side benefit. They identify remaining issues that need to be addressed experimentally

  9. Diagnostic spectral characteristics of damouritization in granite type uranium deposit

    International Nuclear Information System (INIS)

    He Jianguo; Mao Yuxian; Li Jianzhong; Wang Changliang; Feng Mingyue; Rong Jiashu; Zhu Minqiang; Rao Minghui

    2008-01-01

    Spectral characteristics of different alteration type in uranium deposit are the prerequisite of selecting remote sensing spectral bands for uranium reconnaissance and exploration. It is also a basis for mapping alteration zone using imaging spectral data. Taking the No. 201 uranium deposit as example, the paper is focused on the spectral characteristics researching of damouritization in granite type uranium deposite. Through extracting diagnostic spectral feature of damourite and analyzing the reason causing absorption valley, it was found that spectral characteristics of damouritization in Chinese uranium deposit is different from that of illite in the spectral library published abroad. (authors)

  10. Diagnostic spectral characteristics of damouritization in granite type uranium deposit

    Energy Technology Data Exchange (ETDEWEB)

    Jianguo, He; Yuxian, Mao; Jianzhong, Li; Changliang, Wang; Mingyue, Feng; Jiashu, Rong [Beijing Research Inst. of Uranium Geology, Beijing (China); Minqiang, Zhu; Minghui, Rao [East China Univ. of Technology, Fuzhou (China)

    2008-07-15

    Spectral characteristics of different alteration type in uranium deposit are the prerequisite of selecting remote sensing spectral bands for uranium reconnaissance and exploration. It is also a basis for mapping alteration zone using imaging spectral data. Taking the No. 201 uranium deposit as example, the paper is focused on the spectral characteristics researching of damouritization in granite type uranium deposite. Through extracting diagnostic spectral feature of damourite and analyzing the reason causing absorption valley, it was found that spectral characteristics of damouritization in Chinese uranium deposit is different from that of illite in the spectral library published abroad. (authors)

  11. FSD: Frequency Space Differential measurement of CMB spectral distortions

    Science.gov (United States)

    Mukherjee, Suvodip; Silk, Joseph; Wandelt, Benjamin D.

    2018-04-01

    Although the Cosmic Microwave Background agrees with a perfect blackbody spectrum within the current experimental limits, it is expected to exhibit certain spectral distortions with known spectral properties. We propose a new method, Frequency Space Differential (FSD) to measure the spectral distortions in the CMB spectrum by using the inter-frequency differences of the brightness temperature. The difference between the observed CMB temperature at different frequencies must agree with the frequency derivative of the blackbody spectrum, in the absence of any distortion. However, in the presence of spectral distortions, the measured inter-frequency differences would also exhibit deviations from blackbody which can be modeled for known sources of spectral distortions like y & μ. Our technique uses FSD information for the CMB blackbody, y, μ or any other sources of spectral distortions to model the observed signal. Successful application of this method in future CMB missions can provide an alternative method to extract spectral distortion signals and can potentially make it feasible to measure spectral distortions without an internal blackbody calibrator.

  12. Spatiotemporal Evolution of Hanle and Zeeman Synthetic Polarization in a Chromospheric Spectral Line

    Energy Technology Data Exchange (ETDEWEB)

    Carlin, E. S.; Bianda, M., E-mail: escarlin@irsol.es [Istituto Ricerche Solari Locarno, 6600, Locarno, Switzerland, associated to USI, Università della Svizzera Italiana (Switzerland)

    2017-07-01

    Due to the quick evolution of the solar chromosphere, its magnetic field cannot be inferred reliably without accounting for the temporal variations of its polarized light. This has been broadly overlooked in the modeling and interpretation of the polarization, due to technical problems (e.g., lack of temporal resolution or of time-dependent MHD solar models) and/or because many polarization measurements can apparently be explained without dynamics. Here, we show that the temporal evolution is critical for explaining the spectral-line scattering polarization because of its sensitivity to rapidly varying physical quantities and the possibility of signal cancellations and attenuation during extended time integration. For studying the combined effect of time-varying magnetic fields and kinematics, we solved the 1.5D non-LTE problem of the second kind in time-dependent 3D R-MHD solar models and synthesized the Hanle and Zeeman polarization in forward scattering for the chromospheric λ 4227 line. We find that the quiet-Sun polarization amplitudes depend on the periodicity and spectral coherence of the signal enhancements produced by kinematics, but that substantially larger linear polarization signals should exist all over the solar disk for short integration times. The spectral morphology of the polarization is discussed as a combination of Hanle, Zeeman, partial redistribution and dynamic effects. We give physical references for observations by degrading and characterizing our slit time series in different spatiotemporal resolutions. The implications of our results for the interpretation of the second solar spectrum and for the investigation of the solar atmospheric heatings are discussed.

  13. Spectral signature verification using statistical analysis and text mining

    Science.gov (United States)

    DeCoster, Mallory E.; Firpi, Alexe H.; Jacobs, Samantha K.; Cone, Shelli R.; Tzeng, Nigel H.; Rodriguez, Benjamin M.

    2016-05-01

    In the spectral science community, numerous spectral signatures are stored in databases representative of many sample materials collected from a variety of spectrometers and spectroscopists. Due to the variety and variability of the spectra that comprise many spectral databases, it is necessary to establish a metric for validating the quality of spectral signatures. This has been an area of great discussion and debate in the spectral science community. This paper discusses a method that independently validates two different aspects of a spectral signature to arrive at a final qualitative assessment; the textual meta-data and numerical spectral data. Results associated with the spectral data stored in the Signature Database1 (SigDB) are proposed. The numerical data comprising a sample material's spectrum is validated based on statistical properties derived from an ideal population set. The quality of the test spectrum is ranked based on a spectral angle mapper (SAM) comparison to the mean spectrum derived from the population set. Additionally, the contextual data of a test spectrum is qualitatively analyzed using lexical analysis text mining. This technique analyzes to understand the syntax of the meta-data to provide local learning patterns and trends within the spectral data, indicative of the test spectrum's quality. Text mining applications have successfully been implemented for security2 (text encryption/decryption), biomedical3 , and marketing4 applications. The text mining lexical analysis algorithm is trained on the meta-data patterns of a subset of high and low quality spectra, in order to have a model to apply to the entire SigDB data set. The statistical and textual methods combine to assess the quality of a test spectrum existing in a database without the need of an expert user. This method has been compared to other validation methods accepted by the spectral science community, and has provided promising results when a baseline spectral signature is

  14. Enzyme activity measurement via spectral evolution profiling and PARAFAC

    DEFF Research Database (Denmark)

    Baum, Andreas; Meyer, Anne S.; Garcia, Javier Lopez

    2013-01-01

    The recent advances in multi-way analysis provide new solutions to traditional enzyme activity assessment. In the present study enzyme activity has been determined by monitoring spectral changes of substrates and products in real time. The method relies on measurement of distinct spectral...... fingerprints of the reaction mixture at specific time points during the course of the whole enzyme catalyzed reaction and employs multi-way analysis to detect the spectral changes. The methodology is demonstrated by spectral evolution profiling of Fourier Transform Infrared (FTIR) spectral fingerprints using...

  15. Spectral decomposition of tent maps using symmetry considerations

    International Nuclear Information System (INIS)

    Ordonez, G.E.; Driebe, D.J.

    1996-01-01

    The spectral decompostion of the Frobenius-Perron operator of maps composed of many tents is determined from symmetry considerations. The eigenstates involve Euler as well as Bernoulli polynomials. The authors have introduced some new techniques, based on symmetry considerations, enabling the construction of spectral decompositions in a much simpler way than previous construction algorithms, Here we utilize these techniques to construct the spectral decomposition for one- dimensional maps of the unit interval composed of many tents. The construction uses the knowledge of the spectral decomposition of the r-adic map, which involves Bernoulli polynomials and their duals. It will be seen that the spectral decomposition of the tent maps involves both Bernoulli polynomials and Euler polynomials along with the appropriate dual states

  16. M3 spectral analysis of lunar swirls and the link between optical maturation and surface hydroxyl formation at magnetic anomalies

    Science.gov (United States)

    Kramer, G.Y.; Besse, S.; Dhingra, D.; Nettles, J.; Klima, R.; Garrick-Bethell, I.; Clark, Roger N.; Combe, J.-P.; Head, J. W.; Taylor, L.A.; Pieters, C.M.; Boardman, J.; McCord, T.B.

    2011-01-01

    We examined the lunar swirls using data from the Moon Mineralogy Mapper (M3). The improved spectral and spatial resolution of M3 over previous spectral imaging data facilitates distinction of subtle spectral differences, and provides new information about the nature of these enigmatic features. We characterized spectral features of the swirls, interswirl regions (dark lanes), and surrounding terrain for each of three focus regions: Reiner Gamma, Gerasimovich, and Mare Ingenii. We used Principle Component Analysis to identify spectrally distinct surfaces at each focus region, and characterize the spectral features that distinguish them. We compared spectra from small, recent impact craters with the mature soils into which they penetrated to examine differences in maturation trends on- and off-swirl. Fresh, on-swirl crater spectra are higher albedo, exhibit a wider range in albedos and have well-preserved mafic absorption features compared with fresh off-swirl craters. Albedoand mafic absorptions are still evident in undisturbed, on-swirl surface soils, suggesting the maturation process is retarded. The spectral continuum is more concave compared with off-swirl spectra; a result of the limited spectral reddening being mostly constrained to wavelengths less than ∼1500 nm. Off-swirl spectra show very little reddening or change in continuum shape across the entire M3 spectral range. Off-swirl spectra are dark, have attenuated absorption features, and the narrow range in off-swirl albedos suggests off-swirl regions mature rapidly. Spectral parameter maps depicting the relative OH surface abundance for each of our three swirl focus regions were created using the depth of the hydroxyl absorption feature at 2.82 μm. For each of the studied regions, the 2.82 μm absorption feature is significantly weaker on-swirl than off-swirl, indicating the swirls are depleted in OH relative to their surroundings. The spectral characteristics of the swirls and adjacent terrains

  17. Multi-spectral confocal microendoscope for in-vivo imaging

    Science.gov (United States)

    Rouse, Andrew Robert

    The concept of in-vivo multi-spectral confocal microscopy is introduced. A slit-scanning multi-spectral confocal microendoscope (MCME) was built to demonstrate the technique. The MCME employs a flexible fiber-optic catheter coupled to a custom built slit-scan confocal microscope fitted with a custom built imaging spectrometer. The catheter consists of a fiber-optic imaging bundle linked to a miniature objective and focus assembly. The design and performance of the miniature objective and focus assembly are discussed. The 3mm diameter catheter may be used on its own or routed though the instrument channel of a commercial endoscope. The confocal nature of the system provides optical sectioning with 3mum lateral resolution and 30mum axial resolution. The prism based multi-spectral detection assembly is typically configured to collect 30 spectral samples over the visible chromatic range. The spectral sampling rate varies from 4nm/pixel at 490nm to 8nm/pixel at 660nm and the minimum resolvable wavelength difference varies from 7nm to 18nm over the same spectral range. Each of these characteristics are primarily dictated by the dispersive power of the prism. The MCME is designed to examine cellular structures during optical biopsy and to exploit the diagnostic information contained within the spectral domain. The primary applications for the system include diagnosis of disease in the gastro-intestinal tract and female reproductive system. Recent data from the grayscale imaging mode are presented. Preliminary multi-spectral results from phantoms, cell cultures, and excised human tissue are presented to demonstrate the potential of in-vivo multi-spectral imaging.

  18. [Influence of Spectral Pre-Processing on PLS Quantitative Model of Detecting Cu in Navel Orange by LIBS].

    Science.gov (United States)

    Li, Wen-bing; Yao, Lin-tao; Liu, Mu-hua; Huang, Lin; Yao, Ming-yin; Chen, Tian-bing; He, Xiu-wen; Yang, Ping; Hu, Hui-qin; Nie, Jiang-hui

    2015-05-01

    Cu in navel orange was detected rapidly by laser-induced breakdown spectroscopy (LIBS) combined with partial least squares (PLS) for quantitative analysis, then the effect on the detection accuracy of the model with different spectral data ptetreatment methods was explored. Spectral data for the 52 Gannan navel orange samples were pretreated by different data smoothing, mean centralized and standard normal variable transform. Then 319~338 nm wavelength section containing characteristic spectral lines of Cu was selected to build PLS models, the main evaluation indexes of models such as regression coefficient (r), root mean square error of cross validation (RMSECV) and the root mean square error of prediction (RMSEP) were compared and analyzed. Three indicators of PLS model after 13 points smoothing and processing of the mean center were found reaching 0. 992 8, 3. 43 and 3. 4 respectively, the average relative error of prediction model is only 5. 55%, and in one word, the quality of calibration and prediction of this model are the best results. The results show that selecting the appropriate data pre-processing method, the prediction accuracy of PLS quantitative model of fruits and vegetables detected by LIBS can be improved effectively, providing a new method for fast and accurate detection of fruits and vegetables by LIBS.

  19. Spectral backward radiation profile

    International Nuclear Information System (INIS)

    Kwon, Sung Duck; Lee, Keun Hyun; Kim, Bo Ra; Yoon, Suk Soo

    2004-01-01

    Ultrasonic backward radiation profile is frequency-dependent when incident region has deptional gradient of acoustical properties or multi-layers. Until now, we have measured the profiles of principal frequencies of used transducers so that it was not easy to understand the change of the frequency component and spectrum of backward radiation from the profile. We tried to measure the spectral backward radiation profiles using DFP(digital filer package) Lecroy DSO. The very big changes in the shape and pattern of spectral backward radiation profiles leads to the conclusion that this new try could be very effective tool to evaluate frequency dependent surface area.

  20. Rayleigh imaging in spectral mammography

    Science.gov (United States)

    Berggren, Karl; Danielsson, Mats; Fredenberg, Erik

    2016-03-01

    Spectral imaging is the acquisition of multiple images of an object at different energy spectra. In mammography, dual-energy imaging (spectral imaging with two energy levels) has been investigated for several applications, in particular material decomposition, which allows for quantitative analysis of breast composition and quantitative contrast-enhanced imaging. Material decomposition with dual-energy imaging is based on the assumption that there are two dominant photon interaction effects that determine linear attenuation: the photoelectric effect and Compton scattering. This assumption limits the number of basis materials, i.e. the number of materials that are possible to differentiate between, to two. However, Rayleigh scattering may account for more than 10% of the linear attenuation in the mammography energy range. In this work, we show that a modified version of a scanning multi-slit spectral photon-counting mammography system is able to acquire three images at different spectra and can be used for triple-energy imaging. We further show that triple-energy imaging in combination with the efficient scatter rejection of the system enables measurement of Rayleigh scattering, which adds an additional energy dependency to the linear attenuation and enables material decomposition with three basis materials. Three available basis materials have the potential to improve virtually all applications of spectral imaging.