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Sample records for absorbed fraction saf

  1. Estimation of Photon Specific Absorbed Fractions in Digimouse Voxel Phantom using Monte Carlo Simulation Code FLUKA

    PubMed Central

    Sinha, A.; Patni, H.K.; Dixit, B.M.; Painuly, N.K.; Singh, N.

    2016-01-01

    Background: Most preclinical studies are carried out on mice. For internal dose assessment of a mouse, specific absorbed fraction (SAF) values play an important role. In most studies, SAF values are estimated using older standard human organ compositions and values for limited source target pairs. Objective: SAF values for monoenergetic photons of energies 15, 50, 100, 500, 1000 and 4000 keV were evaluated for the Digimouse voxel phantom incorporated in Monte Carlo code FLUKA. The organ sources considered in this study were lungs, skeleton, heart, bladder, testis, stomach, spleen, pancreas, liver, kidney, adrenal, eye and brain. The considered target organs were lungs, skeleton, heart, bladder, testis, stomach, spleen, pancreas, liver, kidney, adrenal and brain. Eye was considered as a target organ only for eye as a source organ. Organ compositions and densities were adopted from International Commission on Radiological Protection (ICRP) publication number 110. Results: Evaluated organ masses and SAF values are presented in tabular form. It is observed that SAF values decrease with increasing the source-to-target distance. The SAF value for self-irradiation decreases with increasing photon energy. The SAF values are also found to be dependent on the mass of target in such a way that higher values are obtained for lower masses. The effect of composition is highest in case of target organ lungs where mass and estimated SAF values are found to have larger differences. Conclusion: These SAF values are very important for absorbed dose calculation for various organs of a mouse. PMID:28144589

  2. Electron specific absorbed fractions for the adult male and female ICRP/ICRU reference computational phantoms

    NASA Astrophysics Data System (ADS)

    Zankl, Maria; Schlattl, Helmut; Petoussi-Henss, Nina; Hoeschen, Christoph

    2012-07-01

    The calculation of radiation dose from internally incorporated radionuclides is based on so-called absorbed fractions (AFs) and specific absorbed fractions (SAFs). SAFs for monoenergetic electrons were calculated for 63 source regions and 67 target regions using the new male and female adult reference computational phantoms adopted by the ICRP and ICRU and the Monte Carlo radiation transport programme package EGSnrc. The SAF values for electrons are opposed to the simplifying assumptions of ICRP Publication 30. The previously applied assumption of electrons being fully absorbed in the source organ itself is not always true at electron energies above approximately 300-500 keV. High-energy electrons have the ability to leave the source organ and, consequently, the electron SAFs for neighbouring organs can reach the same magnitude as those for photons for electron energies above 1 MeV. The reciprocity principle known for photons can be extended to electron SAFs as well, thus making cross-fire electron SAFs mass-independent. To quantify the impact of the improved electron dosimetry in comparison to the dosimetry using the simple assumptions of ICRP Publication 30, absorbed doses per administered activity of three radiopharmaceuticals were evaluated with and without explicit electron transport. The organ absorbed doses per administered activity for the two evaluation methods agree within 2%-3% for most organs for radionuclides with decay spectra having electron energies below a few hundred keV and within approximately 20% if higher electron energies are involved. An important exception is the urinary bladder wall, where the dose is overestimated by 60-150% using the simplified ICRP 30 approach for the radiopharmaceuticals of this study.

  3. Specific absorbed fractions of electrons and photons for Rad-HUMAN phantom using Monte Carlo method

    NASA Astrophysics Data System (ADS)

    Wang, Wen; Cheng, Meng-Yun; Long, Peng-Cheng; Hu, Li-Qin

    2015-07-01

    The specific absorbed fractions (SAF) for self- and cross-irradiation are effective tools for the internal dose estimation of inhalation and ingestion intakes of radionuclides. A set of SAFs of photons and electrons were calculated using the Rad-HUMAN phantom, which is a computational voxel phantom of a Chinese adult female that was created using the color photographic image of the Chinese Visible Human (CVH) data set by the FDS Team. The model can represent most Chinese adult female anatomical characteristics and can be taken as an individual phantom to investigate the difference of internal dose with Caucasians. In this study, the emission of mono-energetic photons and electrons of 10 keV to 4 MeV energy were calculated using the Monte Carlo particle transport calculation code MCNP. Results were compared with the values from ICRP reference and ORNL models. The results showed that SAF from the Rad-HUMAN have similar trends but are larger than those from the other two models. The differences were due to the racial and anatomical differences in organ mass and inter-organ distance. The SAFs based on the Rad-HUMAN phantom provide an accurate and reliable data for internal radiation dose calculations for Chinese females. Supported by Strategic Priority Research Program of Chinese Academy of Sciences (XDA03040000), National Natural Science Foundation of China (910266004, 11305205, 11305203) and National Special Program for ITER (2014GB112001)

  4. Absorbed fractions for electrons in ellipsoidal volumes

    NASA Astrophysics Data System (ADS)

    Amato, E.; Lizio, D.; Baldari, S.

    2011-01-01

    We applied a Monte Carlo simulation in Geant4 in order to calculate the absorbed fractions for monoenergetic electrons in the energy interval between 10 keV and 2 MeV, uniformly distributed in ellipsoids made from soft tissue. For each volume, we simulated a spherical shape, four oblate and four prolate ellipsoids, and one scalene shape. For each energy and for every geometrical configuration, an analytical relationship between the absorbed fraction and a 'generalized radius' was found, and the dependence of the fit parameters from electron energy is discussed and fitted by proper parametric functions. With the proposed formulation, the absorbed fraction for electrons in the 10-2000 keV energy range can be calculated for all volumes and for every ellipsoidal shape of practical interest. This method can be directly applied to evaluation of the absorbed fraction from the radionuclide emission of monoenergetic electrons, such as Auger or conversion electrons. The average deposited energy per disintegration in the case of extended beta spectra can be evaluated through integration. Two examples of application to a pure beta emitter such as 90Y and to 131I, whose emission include monoenergetic and beta electrons plus gamma photons, are presented. This approach represent a generalization of our previous studies, allowing a comprehensive treatment of absorbed fractions from electron and photon sources uniformly distributed in ellipsoidal volumes of any ellipticity and volume, in the whole range of practical interest for internal dosimetry in nuclear medicine applications, as well as in radiological protection estimations of doses from an internal contamination.

  5. Absorbed fractions for electrons in ellipsoidal volumes.

    PubMed

    Amato, E; Lizio, D; Baldari, S

    2011-01-21

    We applied a Monte Carlo simulation in Geant4 in order to calculate the absorbed fractions for monoenergetic electrons in the energy interval between 10 keV and 2 MeV, uniformly distributed in ellipsoids made from soft tissue. For each volume, we simulated a spherical shape, four oblate and four prolate ellipsoids, and one scalene shape. For each energy and for every geometrical configuration, an analytical relationship between the absorbed fraction and a 'generalized radius' was found, and the dependence of the fit parameters from electron energy is discussed and fitted by proper parametric functions. With the proposed formulation, the absorbed fraction for electrons in the 10-2000 keV energy range can be calculated for all volumes and for every ellipsoidal shape of practical interest. This method can be directly applied to evaluation of the absorbed fraction from the radionuclide emission of monoenergetic electrons, such as Auger or conversion electrons. The average deposited energy per disintegration in the case of extended beta spectra can be evaluated through integration. Two examples of application to a pure beta emitter such as (90)Y and to (131)I, whose emission include monoenergetic and beta electrons plus gamma photons, are presented. This approach represent a generalization of our previous studies, allowing a comprehensive treatment of absorbed fractions from electron and photon sources uniformly distributed in ellipsoidal volumes of any ellipticity and volume, in the whole range of practical interest for internal dosimetry in nuclear medicine applications, as well as in radiological protection estimations of doses from an internal contamination.

  6. Specific absorbed fractions of energy from internal photon sources in brain tumor and cerebrospinal fluid

    SciTech Connect

    Evans, J.F. )); Stubbs, J.B. )

    1995-03-01

    Transferrin, radiolabeled with In-111, can be coinjected into glioblastoma multiforme lesions, and subsequent scintigraphic imaging can demonstrate the biokinetics of the cytotoxic transferrin. The administration of [sup 111]In transferrin into a brain tumor results in distribution of radioactivity in the brain, brain tumor, and the cerebrospinal fluid (CSF). Information about absorbed radiation doses to these regions, as well as other nearby tissues and organs, is important for evaluating radiation-related risks from this procedure. The radiation dose is usually estimated for a mathematical representation of the human body. We have included source/target regions for the eye, lens of the eye, spinal column, spinal CSF, cranial CSF, and a 100-g tumor within the brain of an adult male phantom developed by Cristy and Eckerman. The spinal column, spinal CSF, and the eyes have not been routinely included in photon transport simulations. Specific absorbed fractions (SAFs) as a function of photon energy were calculated using the ALGAMP computer code, which utilizes Monte Carlo techniques for simulating photon transport. The ALGAMP code was run three times, with the source activity distributed uniformly within the tumor, cranial CSF, and the spinal CSF volumes. These SAFs, which were generated for 12 discrete photon energies ranging from 0.01 to 4.0 MeV, were used with decay scheme data to calculate [ital S]-values needed for estimating absorbed doses. [ital S]-values for [sup 111]In are given for three source regions (brain tumor, cranial CSF, and spinal CSF) and all standard target regions/organs, the eye and lens, as well as to tissues within these source regions. [ital S]-values for the skeletal regions containing active marrow are estimated. These results are useful in evaluating the radiation doses from intracranial administration of [sup 111]In transferrin.

  7. Application of the ICRP/ICRU reference computational phantoms to internal dosimetry: calculation of specific absorbed fractions of energy for photons and electrons.

    PubMed

    Hadid, L; Desbrée, A; Schlattl, H; Franck, D; Blanchardon, E; Zankl, M

    2010-07-07

    The emission of radiation from a contaminated body region is connected with the dose received by radiosensitive tissue through the specific absorbed fractions (SAFs) of emitted energy, which is therefore an essential quantity for internal dose assessment. A set of SAFs were calculated using the new adult reference computational phantoms, released by the International Commission on Radiological Protection (ICRP) together with the International Commission on Radiation Units and Measurements (ICRU). Part of these results has been recently published in ICRP Publication 110 (2009 Adult reference computational phantoms (Oxford: Elsevier)). In this paper, we mainly discuss the results and also present them in numeric form. The emission of monoenergetic photons and electrons with energies ranging from 10 keV to 10 MeV was simulated for three source organs: lungs, thyroid and liver. SAFs were calculated for four target regions in the body: lungs, colon wall, breasts and stomach wall. For quality assurance purposes, the simulations were performed simultaneously at the Helmholtz Zentrum München (HMGU, Germany) and at the Institute for Radiological Protection and Nuclear Safety (IRSN, France), using the Monte Carlo transport codes EGSnrc and MCNPX, respectively. The comparison of results shows overall agreement for photons and high-energy electrons with differences lower than 8%. Nevertheless, significant differences were found for electrons at lower energy for distant source/target organ pairs. Finally, the results for photons were compared to the SAF values derived using mathematical phantoms. Significant variations that can amount to 200% were found. The main reason for these differences is the change of geometry in the more realistic voxel body models. For electrons, no SAFs have been computed with the mathematical phantoms; instead, approximate formulae have been used by both the Medical Internal Radiation Dose committee (MIRD) and the ICRP due to the limitations imposed

  8. Application of the ICRP/ICRU reference computational phantoms to internal dosimetry: calculation of specific absorbed fractions of energy for photons and electrons

    NASA Astrophysics Data System (ADS)

    Hadid, L.; Desbrée, A.; Schlattl, H.; Franck, D.; Blanchardon, E.; Zankl, M.

    2010-07-01

    The emission of radiation from a contaminated body region is connected with the dose received by radiosensitive tissue through the specific absorbed fractions (SAFs) of emitted energy, which is therefore an essential quantity for internal dose assessment. A set of SAFs were calculated using the new adult reference computational phantoms, released by the International Commission on Radiological Protection (ICRP) together with the International Commission on Radiation Units and Measurements (ICRU). Part of these results has been recently published in ICRP Publication 110 (2009 Adult reference computational phantoms (Oxford: Elsevier)). In this paper, we mainly discuss the results and also present them in numeric form. The emission of monoenergetic photons and electrons with energies ranging from 10 keV to 10 MeV was simulated for three source organs: lungs, thyroid and liver. SAFs were calculated for four target regions in the body: lungs, colon wall, breasts and stomach wall. For quality assurance purposes, the simulations were performed simultaneously at the Helmholtz Zentrum München (HMGU, Germany) and at the Institute for Radiological Protection and Nuclear Safety (IRSN, France), using the Monte Carlo transport codes EGSnrc and MCNPX, respectively. The comparison of results shows overall agreement for photons and high-energy electrons with differences lower than 8%. Nevertheless, significant differences were found for electrons at lower energy for distant source/target organ pairs. Finally, the results for photons were compared to the SAF values derived using mathematical phantoms. Significant variations that can amount to 200% were found. The main reason for these differences is the change of geometry in the more realistic voxel body models. For electrons, no SAFs have been computed with the mathematical phantoms; instead, approximate formulae have been used by both the Medical Internal Radiation Dose committee (MIRD) and the ICRP due to the limitations imposed

  9. Absorbed fractions for alpha particles in ellipsoidal volumes

    NASA Astrophysics Data System (ADS)

    Amato, Ernesto; Italiano, Antonio; Baldari, Sergio

    2013-08-01

    Internal dosimetry of alpha particles is gaining attention due to the increasing applications in cancer treatment and also for the assessment of environmental contamination from radionuclides. We developed a Monte Carlo simulation in GEANT4 in order to calculate the absorbed fractions for monoenergetic alpha particles in the energy interval between 0.1 and 10 MeV, uniformly distributed in ellipsoids made of soft tissue. For each volume, we simulated a spherical shape, three oblate and three prolate ellipsoids, and one scalene shape. For each energy and for every geometrical configuration, an analytical relationship between the absorbed fraction and a ‘generalized radius’ was found; and the dependence of the fit parameters on the alpha energy is discussed and fitted by parametric functions. With the proposed formulation, the absorbed fraction for alpha particles in the energy range explored can be calculated for volumes and for ellipsoidal shapes of practical interest. This method can be applied to the evaluation of absorbed fraction from alpha-emitting radionuclides. The contribution to the deposited energy coming from electron and photon emissions can be accounted for exploiting the specific formulations previously introduced. As an example of application, the dosimetry of 213Bi and its decay chain in ellipsoids is reported.

  10. Estimation of specific absorbed fractions for selected organs due to photons emitted by activity deposited in the human respiratory tract using ICRP/ICRU male voxel phantom in FLUKA.

    PubMed

    Patni, H K; Akar, D K; Nadar, M Y; Ghare, V P; Rao, D D; Sarkar, P K

    2013-01-01

    The ICRP/ICRU adult male reference voxel phantom incorporated in Monte Carlo code FLUKA is used for estimating specific absorbed fractions (SAFs) for photons due to the presence of internal radioactive contamination in the human respiratory tract (RT). The compartments of the RT, i.e. extrathoracic (ET1 and ET2) and thoracic (bronchi, bronchioles, alveolar interstitial) regions, lymph nodes of both regions and lungs are considered as the source organs. The nine organs having high tissue weighting factors such as colon, lungs, stomach wall, breast, testis, urinary bladder, oesophagus, liver and thyroid and the compartments of the RT are considered as target organs. Eleven photon energies in the range of 15 keV to 4 MeV are considered for each source organ and the computed SAF values are presented in the form of tables. For the target organs in the proximity of the source organ including the source organ itself, the SAF values are relatively higher and decrease with increase in energy. As the distance between source and target organ increases, SAF values increase with energy and reach maxima depending on the position of the target organ with respect to the source organ. The SAF values are relatively higher for the target organs with smaller masses. Large deviations are seen in computed SAF values from the existing MIRD phantom data for most of the organs. These estimated SAF values play an important role in the estimation of equivalent dose to various target organs of a worker due to intake by inhalation pathway.

  11. Monte Carlo calculation of specific absorbed fractions: variance reduction techniques

    NASA Astrophysics Data System (ADS)

    Díaz-Londoño, G.; García-Pareja, S.; Salvat, F.; Lallena, A. M.

    2015-04-01

    The purpose of the present work is to calculate specific absorbed fractions using variance reduction techniques and assess the effectiveness of these techniques in improving the efficiency (i.e. reducing the statistical uncertainties) of simulation results in cases where the distance between the source and the target organs is large and/or the target organ is small. The variance reduction techniques of interaction forcing and an ant colony algorithm, which drives the application of splitting and Russian roulette, were applied in Monte Carlo calculations performed with the code penelope for photons with energies from 30 keV to 2 MeV. In the simulations we used a mathematical phantom derived from the well-known MIRD-type adult phantom. The thyroid gland was assumed to be the source organ and urinary bladder, testicles, uterus and ovaries were considered as target organs. Simulations were performed, for each target organ and for photons with different energies, using these variance reduction techniques, all run on the same processor and during a CPU time of 1.5 · 105 s. For energies above 100 keV both interaction forcing and the ant colony method allowed reaching relative uncertainties of the average absorbed dose in the target organs below 4% in all studied cases. When these two techniques were used together, the uncertainty was further reduced, by a factor of 0.5 or less. For photons with energies below 100 keV, an adapted initialization of the ant colony algorithm was required. By using interaction forcing and the ant colony algorithm, realistic values of the specific absorbed fractions can be obtained with relative uncertainties small enough to permit discriminating among simulations performed with different Monte Carlo codes and phantoms. The methodology described in the present work can be employed to calculate specific absorbed fractions for arbitrary arrangements, i.e. energy spectrum of primary radiation, phantom model and source and target organs.

  12. Absorbed fractions for alpha-particles in tissues of cortical bone

    NASA Astrophysics Data System (ADS)

    Watchman, Christopher J.; Bolch, Wesley E.

    2009-10-01

    Bone-seeking alpha-particle emitting radionuclides are common health physics hazards. Additionally, they are under consideration as an option for therapeutic molecular radiotherapy applications. Current dose models do not account for energy or bone-site dependence as shown by alpha-particle absorbed fractions given in ICRP Publication 30. Energy-dependent, yet bone-site independent, alpha-particle absorbed fractions have been presented by the models of Stabin and Siegel (2003 Health Phys. 85 294-310). In this work, a chord-based computational model of alpha-particle transport in cortical bone has been developed that explicitly accounts for both the bone-site and particle-energy dependence of alpha-particle absorbed fractions in this region of the skeleton. The model accounts for energy deposition to three targets: cortical endosteum, haversian space tissues and cortical bone. Path length distributions for cortical bone given in Beddoe (1977 Phys. Med. Biol. 22 298-308) provided additional transport regions in the absorbed fraction calculation. Significant variations in absorbed fractions between different skeletal sites were observed. Differences were observed between this model and the absorbed fractions given in ICRP Publication 30, which varied by as much as a factor of 2.1 for a cortical bone surface source irradiating cortical endosteum.

  13. A mathematical model of the nine-month pregnant woman for calculating specific absorbed fractions

    SciTech Connect

    Watson, E.E.; Stabin, M.G.

    1986-01-01

    Existing models that allow calculation of internal doses from radionuclide intakes by both men and women are based on a mathematical model of Reference Man. No attempt has been made to allow for the changing geometric relationships that occur during pregnancy which would affect the doses to the mother's organs and to the fetus. As pregnancy progresses, many of the mother's abdominal organs are repositioned, and their shapes may be somewhat changed. Estimation of specific absorbed fractions requires that existing mathematical models be modified to accommodate these changes. Specific absorbed fractions for Reference Woman at three, six, and nine months of pregnancy should be sufficient for estimating the doses to the pregnant woman and the fetus. This report describes a model for the pregnant woman at nine months. An enlarged uterus was incorporated into a model for Reference Woman. Several abdominal organs as well as the exterior of the trunk were modified to accommodate the new uterus. This model will allow calculation of specific absorbed fractions for the fetus from photon emitters in maternal organs. Specific absorbed fractions for the repositioned maternal organs from other organs can also be calculated. 14 refs., 2 figs.

  14. Experimental demonstration of a transparent graphene millimetre wave absorber with 28% fractional bandwidth at 140 GHz

    NASA Astrophysics Data System (ADS)

    Wu, Bian; Tuncer, Hatice M.; Naeem, Majid; Yang, Bin; Cole, Matthew T.; Milne, William I.; Hao, Yang

    2014-02-01

    The development of transparent radio-frequency electronics has been limited, until recently, by the lack of suitable materials. Naturally thin and transparent graphene may lead to disruptive innovations in such applications. Here, we realize optically transparent broadband absorbers operating in the millimetre wave regime achieved by stacking graphene bearing quartz substrates on a ground plate. Broadband absorption is a result of mutually coupled Fabry-Perot resonators represented by each graphene-quartz substrate. An analytical model has been developed to predict the absorption performance and the angular dependence of the absorber. Using a repeated transfer-and-etch process, multilayer graphene was processed to control its surface resistivity. Millimetre wave reflectometer measurements of the stacked graphene-quartz absorbers demonstrated excellent broadband absorption of 90% with a 28% fractional bandwidth from 125-165 GHz. Our data suggests that the absorbers' operation can also be extended to microwave and low-terahertz bands with negligible loss in performance.

  15. Improved estimates of the radiation absorbed dose to the urinary bladder wall.

    PubMed

    Andersson, Martin; Minarik, David; Johansson, Lennart; Mattsson, Sören; Leide-Svegborn, Sigrid

    2014-05-07

    Specific absorbed fractions (SAFs) have been calculated as a function of the content in the urinary bladder in order to allow more realistic calculations of the absorbed dose to the bladder wall. The SAFs were calculated using the urinary bladder anatomy from the ICRP male and female adult reference computational phantoms. The urinary bladder and its content were approximated by a sphere with a wall of constant mass, where the thickness of the wall depended on the amount of urine in the bladder. SAFs were calculated for males and females with 17 different urinary bladder volumes from 10 to 800 mL, using the Monte Carlo computer program MCNP5, at 25 energies of mono-energetic photons and electrons ranging from 10 KeV to 10 MeV. The decay was assumed to be homogeneously distributed in the urinary bladder content and the urinary bladder wall, and the mean absorbed dose to the urinary bladder wall was calculated. The Monte Carlo simulations were validated against measurements made with thermoluminescent dosimeters. The SAFs obtained for a urine volume of 200 mL were compared to the values calculated for the urinary bladder wall using the adult reference computational phantoms. The mean absorbed dose to the urinary wall from (18)F-FDG was found to be 77 µGy/MBq formales and 86 µGy/MBq for females, while for (99m)Tc-DTPA the mean absorbed doses were 80 µGy/MBq for males and 86 µGy/MBq for females. Compared to calculations using a constant value of the SAF from the adult reference computational phantoms, the mean absorbed doses to the bladder wall were 60% higher for (18)F-FDG and 30% higher for (99m)Tc-DTPA using the new SAFs.

  16. Traversal of cells by radiation and absorbed fraction estimates for electrons and alpha particles

    SciTech Connect

    Eckerman, K.F.; Ryman, J.C.; Taner, A.C.; Kerr, G.D.

    1985-01-01

    Consideration of the pathlength which radiation traverses in a cell is central to algorithms for estimating energy deposition on a cellular level. Distinct pathlength distributions occur for radionuclides: (1) uniformly distributed in space about the cell (referred to as -randomness); (2) uniformly distributed on the surface of the cell (S-randomness); and (3) uniformly distributed within the cell volume (I-randomness). For a spherical cell of diameter d, the mean pathlengths are 2/3d, 1/2d, and 3/4d, respectively, for these distributions. Algorithms for simulating the path of radiation through a cell are presented and the absorbed fraction in the cell and its nucleus are tabulated for low energy electrons and alpha particles emitted on the surface of spherical cells. The algorithms and absorbed fraction data should be of interest to those concerned with the dosimetry of radionuclide-labeled monoclonal antibodies. 8 refs., 3 figs., 2 tabs.

  17. Electron absorbed fractions and dose conversion factors for marrow and bone by skeletal regions

    SciTech Connect

    Eckerman, K.F.; Stabin, M.G.

    2000-02-01

    The possible inductions of bone cancer and leukemia are the two health effects of primary concern in the irradiation of the skeleton. The relevant target tissues to consider in the dosimetric evaluation have been the cells on or near endosteal surfaces of bone, from which osteosarcomas are thought to arise, and hematopoietic bone marrow, which is associated with leukemia. The complex geometry of the soft tissue-bone intermixture makes calculations of absorbed doses to these target regions a difficult problem. In the case of photon or neutron radiations, charged particle equilibrium may not exist in the vicinity of a soft tissue-bone mineral interface. In this paper, absorbed fraction data are developed for calculations of the dose in the target tissues from electron emitters deposited within the volume or on the surfaces of trabecular bone. The skeletal average absorbed fractions presented are consistent with usage of this quantity in the contemporary dosimetric formulations of the International Commission on Radiological Protection (ICRP). Implementation of the new bone and marrow model is then developed within the context of the calculational schema of the Medical Internal Radiation Dose (MIRD) Committee. Model parameters relevant to the calculation of dose conversion factors (S values) for different regions of the skeleton of individuals of various age are described, and an example calculation is performed for a monoclonal antibody which localizes in the marrow. The utility of these calculations for radiation dose calculations in nuclear medicine is discussed.

  18. Experimental demonstration of a transparent graphene millimetre wave absorber with 28% fractional bandwidth at 140 GHz

    PubMed Central

    Wu, Bian; Tuncer, Hatice M.; Naeem, Majid; Yang, Bin; Cole, Matthew T.; Milne, William I.; Hao, Yang

    2014-01-01

    The development of transparent radio-frequency electronics has been limited, until recently, by the lack of suitable materials. Naturally thin and transparent graphene may lead to disruptive innovations in such applications. Here, we realize optically transparent broadband absorbers operating in the millimetre wave regime achieved by stacking graphene bearing quartz substrates on a ground plate. Broadband absorption is a result of mutually coupled Fabry-Perot resonators represented by each graphene-quartz substrate. An analytical model has been developed to predict the absorption performance and the angular dependence of the absorber. Using a repeated transfer-and-etch process, multilayer graphene was processed to control its surface resistivity. Millimetre wave reflectometer measurements of the stacked graphene-quartz absorbers demonstrated excellent broadband absorption of 90% with a 28% fractional bandwidth from 125–165 GHz. Our data suggests that the absorbers' operation can also be extended to microwave and low-terahertz bands with negligible loss in performance. PMID:24549254

  19. Photon and electron absorbed fractions calculated from a new tomographic rat model

    NASA Astrophysics Data System (ADS)

    Peixoto, P. H. R.; Vieira, J. W.; Yoriyaz, H.; Lima, F. R. A.

    2008-10-01

    This paper describes the development of a tomographic model of a rat developed using CT images of an adult male Wistar rat for radiation transport studies. It also presents calculations of absorbed fractions (AFs) under internal photon and electron sources using this rat model and the Monte Carlo code MCNP. All data related to the developed phantom were made available for the scientific community as well as the MCNP inputs prepared for AF calculations in that phantom and also all estimated AF values, which could be used to obtain absorbed dose estimates—following the MIRD methodology—in rats similar in size to the presently developed model. Comparison between the rat model developed in this study and that published by Stabin et al (2006 J. Nucl. Med. 47 655) for a 248 g Sprague-Dawley rat, as well as between the estimated AF values for both models, has been presented.

  20. SAF values for internal photon emitters calculated for the RPI-P pregnant-female models using Monte Carlo methods

    SciTech Connect

    Shi, C. Y.; Xu, X. George; Stabin, Michael G.

    2008-07-15

    Estimates of radiation absorbed doses from radionuclides internally deposited in a pregnant woman and her fetus are very important due to elevated fetal radiosensitivity. This paper reports a set of specific absorbed fractions (SAFs) for use with the dosimetry schema developed by the Society of Nuclear Medicine's Medical Internal Radiation Dose (MIRD) Committee. The calculations were based on three newly constructed pregnant female anatomic models, called RPI-P3, RPI-P6, and RPI-P9, that represent adult females at 3-, 6-, and 9-month gestational periods, respectively. Advanced Boundary REPresentation (BREP) surface-geometry modeling methods were used to create anatomically realistic geometries and organ volumes that were carefully adjusted to agree with the latest ICRP reference values. A Monte Carlo user code, EGS4-VLSI, was used to simulate internal photon emitters ranging from 10 keV to 4 MeV. SAF values were calculated and compared with previous data derived from stylized models of simplified geometries and with a model of a 7.5-month pregnant female developed previously from partial-body CT images. The results show considerable differences between these models for low energy photons, but generally good agreement at higher energies. These differences are caused mainly by different organ shapes and positions. Other factors, such as the organ mass, the source-to-target-organ centroid distance, and the Monte Carlo code used in each study, played lesser roles in the observed differences in these. Since the SAF values reported in this study are based on models that are anatomically more realistic than previous models, these data are recommended for future applications as standard reference values in internal dosimetry involving pregnant females.

  1. ELECTRON ABSORBED FRACTIONS IN AN IMAGE-BASED MICROSCOPIC SKELETAL DOSIMETRY MODEL OF CHINESE ADULT MALE.

    PubMed

    Gao, Shenshen; Ren, Li; Qiu, Rui; Wu, Zhen; Li, Chunyan; Li, Junli

    2017-01-10

    Based on the Chinese reference adult male voxel model, a set of microscopic skeletal models of Chinese adult male is constructed through the processes of computed tomography (CT) imaging, bone coring, micro-CT imaging, image segmentation, merging into macroscopic bone model and implementation in Geant4. At the step of image segmentation, a new bone endosteum (BE) segmentation method is realized by sampling. The set of model contains 32 spongiosa samples with voxel size of 19 μm cubes. The microscopic spongiosa bone data for Chinese adult male are provided. Electron absorbed fractions in red bone marrow (RBM) and BE are calculated. Source tissues include the bone marrow (red and yellow), trabecular bone (surfaces and volumes) and cortical bone (surfaces and volumes). Target tissues include RBM and BE. Electron energies range from 10 keV to 10 MeV. Additionally, comparison of the result with other investigations is provided.

  2. A study of fraction of absorbed photosynthetically active radiation characteristics based on SAIL model simulation

    NASA Astrophysics Data System (ADS)

    Li, Li; Du, Yongming; Tang, Yong; Liu, Qinhuo

    2012-10-01

    The photosynthetically Active Radiation reached to plant canopy could be divided into two parts that are direct radiation and diffuse radiation. The paths into the vegetation canopy are different of these two kinds of radiation. It makes Fraction of Absorbed Photosynthetically Active Radiation (FPAR) different. So this difference between direct FPAR and diffuse FPAR must be determined to decide whether it should be considered into the FPAR inversion model. In this study, the SAIL model was modified which could output direct FPAR and diffuse FPAR. Then with the change of input parameters such as solar zenith angle, visiblity and LAI, the direct FPAR and diffuse FPAR would be change. When the visibility is set as 5km, 15km and 30km, the contribution of scattering of FPAR on the total FPAR is 52.6%, 29.3% and 21.7%. The error between whole FPAR and direct FPAR is reduced with the increasing of visibility and increased with the reducing of LAI. The maximum relative error is 13.2%. From the simulation analyses, we could see that direct and diffuse FPAR are different with the changes of environment variables. So when modeling of FPAR, the diffuse part cannot be ignored. Direct FPAR and diffuse FPAR must be modeled respectively. This separation will help improve the accuracy of FPAR inversion.

  3. Specific absorbed fractions of energy at various ages from internal photon sources: 6, Newborn

    SciTech Connect

    Cristy, M.; Eckerman, K.F.

    1987-04-01

    Specific absorbed fraction (PHI's) in various organs of the body (target organs) from sources of monoenergetic photons in various other organs (source organs) are tabulated. In this volume PHI-values are tabulated for a newborn or 3.4-kg person. These PHI-values can be used in calculating the photon component of the dose-equivalent rate in a given target from a given radionuclide that is present in a given source organ. The International Commission on Radiological Protection recognizes that the endosteal, or bone surface, cells are the tissue at risk for bone cancer. We have applied the dosimetry methods that Spiers and co-workers developed for beta-emitting radionuclides deposited in bone to follow the transport of secondary electrons that were freed by photon interactions through the microscopic structure of the skeleton. With these methods we can estimate PHI in the endosteal cells and can better estimate PHI in the active marrow; the latter is overestimated with other methods at photon energies below 200 keV. 12 refs., 2 tabs.

  4. Simulation of tunable Cr:YSO Q-switched Cr:LiSAF laser

    NASA Astrophysics Data System (ADS)

    Chen, Hsiu-Fen; Hsieh, Shang-Wei; Kuo, Yen-Kuang

    2005-01-01

    In this work, we numerically investigate the passive Q-switching performance of the tunable Cr:YSO Q-switched Cr:LiSAF laser over its entire tuning range. Specifically, the optical performance of the Cr:YSO Q-switched Cr:LiSAF laser as functions of the initial population in the ground state of the Cr:YSO saturable absorber, the pumping rate, the reflectivity of the output coupler, and the dissipative loss inside the laser cavity are studied. Simulation results show that the Cr:YSO is an effective saturable absorber Q switch for the Cr:LiSAF laser over its entire tuning range. Unlike the Cr:YSO Q-switched alexandrite laser and the Cr:YSO Q-switched Cr:LiCAF laser, the Cr:YSO Q-switched Cr:LiSAF laser has similar passive Q-switching performance when the laser polarization is along each of the three principal axes of the Cr:YSO. The results obtained numerically in this work are in good agreement with those obtained experimentally by other researchers. Our simulation results indicate that, a Q-switched laser pulse with an output energy of 10 mJ and a pulse width of 17 ns may be obtained at 850 nm, the peak of its tuning spectrum.

  5. Optimum combinations of visible and near-infrared reflectances for estimating the fraction of photosynthetically available radiation absorbed by plants

    NASA Technical Reports Server (NTRS)

    Podaire, Alain; Deschamps, Pierre-Yves; Frouin, R.; Asrar, Ghassem

    1991-01-01

    A useful parameter to estimate terrestrial primary productivity, that can be sensed from space, is the daily averaged fraction of Photosynthetically Available Radiation (PAR) absorbed by plants. To evaluate this parameter, investigators have relied on the fact that the relative amount of radiation reflected by a vegetated surface in the visible and near infrared depends on the fraction of the surface covered by the vegetation and therefore, correlates with absorbed PAR. They have used vegetation indices, namely normalized difference and simple ratio, to derive absorbed PAR. The problem with normalized difference and simple ratio is first, they are non linear functions of radiance or reflectance and therefore, cannot be readily applied to heterogeneous targets, second, they are used in generally nonlinear relationships, which make time integrals of the indices not proportional to primary productivity, and third, the relationships depend strongly on the type of canopy and background. To remove these limitations, linear combinations of visible and near infrared reflectances at optimum (one or two) viewing zenith angles are proposed.

  6. The EUMETSAT ocean and sea ice SAF (OSI SAF) : Overview on the project and the products

    NASA Astrophysics Data System (ADS)

    Guevel, Guenole

    The EUMETSAT OSI SAF (www.osi-saf.org) was created in 1997 as an answer to requirements for a comprehensive information derived from meteorological satellites at the ocean-atmosphere interface. The OSI SAF consortium is constituted of Météo-France as leading entity, and Met.no (Norske ee Meteorologiske Institutt), DMI (Danish Meteorological Institute), SMHI (Swedish Meteorolog-ical and Hydrological Institute), KNMI (Koninklijk Nederlands Meteorologisch Instituut) and IFREMER (Institut Français de Recherche pour l'Exploitation de la MER) as co-operating c entities. The two previous phases of the EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI SAF), the Development phase (1997-2002) and the IOP (initial Operations Phase, 2002-2007) met the main target which was to develop, validate and then produce operationally quality controlled satellite-derived products related to four key parameters of the sea surface (Sea Surface Temperature, Radiative Fluxes, Sea Ice, Wind) over various geographical coverage from regional to global. These products are currently available in near real time both through EUMETCAST and local FTP servers, and off line from local archive. Archiving at EUMETSAT Data Center is also being implemented. The current phase of the EUMETSAT OSI SAF, the CDOP (Continuous Development and Operations Phase, 2007-2012) has taken into account new requirements expressed in particular in the context of GODAE, GHRSST and GCOS at international level, and GMES (through MyOcean) at European level, with in particular a strong need for increasing the temporal and geographical resolution of the products and user friendly interfaces allowing access to high level allowing flexible extraction An overview on the OSI SAF project and its current and future production in the time frame of the CDOP will be presented, as well as first glance on the following phase, the CDOP-2, that will cover 2012 to 2017.

  7. Dependence of microwave absorption properties on ferrite volume fraction in MnZn ferrite/rubber radar absorbing materials

    NASA Astrophysics Data System (ADS)

    Gama, Adriana M.; Rezende, Mirabel C.; Dantas, Christine C.

    2011-11-01

    We report the analysis of measurements of the complex magnetic permeability ( μr) and dielectric permittivity ( ɛr) spectra of a rubber radar absorbing material (RAM) with various MnZn ferrite volume fractions. The transmission/reflection measurements were carried out in a vector network analyzer. Optimum conditions for the maximum microwave absorption were determined by substituting the complex permeability and permittivity in the impedance matching equation. Both the MnZn ferrite content and the RAM thickness effects on the microwave absorption properties, in the frequency range of 2-18 GHz, were evaluated. The results show that the complex permeability and permittivity spectra of the RAM increase directly with the ferrite volume fraction. Reflection loss calculations by the impedance matching degree (reflection coefficient) show the dependence of this parameter on both thickness and composition of RAM.

  8. SAF1. Standard Agent Framework 1

    SciTech Connect

    Goldsmith, S.Y

    1997-06-01

    The Standard Agent framework provides an extensible object-oriented development environment suitable for use in both research and applications projects. The SAF provides a means for constructing and customizing multi-agent systems through specialization of standard base classes (architecture-driven framework) and by composition of component classes (data driven framework). The standard agent system is implemented as an extensible object-centerd framework. Four concrete base classes are developed: (1) Standard Agency; (2) Standard Agent; (3) Human Factor, and (4) Resources. The object-centered framework developed and utilized provides the best comprimise between generality and flexibility available in agent development systems today.

  9. Use of narrow-band spectra to estimate the fraction of absorbed photosynthetically active radiation

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G.; Huemmrich, Karl F.; Goward, Samuel N.

    1990-01-01

    A novel approach is proposed for using high-spectral resolution imagers to estimate the fraction of photosynthetically active radiation adsorbed, f(apar), by vegetated land surfaces. In comparison to approaches using broad-band vegetation indices, the proposed method appears to be relatively insensitive to the reflectance of nonphotosynthetically active material beneath the canopy, such as leaf litter or soil. The method is based on a relationship between the second derivative of the reflectance vs wavelength function for terrestrial vegetation and f(apar). The relationship can be defined by the second derivatives in either of two windows, one in the visible region centered at 0.69 micron, another in the near-infrared region centered at 0.74 micron.

  10. Leaf Area Index and Fraction of Absorbed PAR Products from Terra and Aqua MODIS Sensors: Analysis, Validation, and Refinement

    NASA Astrophysics Data System (ADS)

    Myneni, Ranga; Knyazikhin, Yuri; Shabanov, Nicolay

    The MODerate resolution Imaging Spectroradiometer (MODIS) onboard NASA's Terra and Aqua platforms is designed to monitor the Earth's atmosphere, oceans, and land surface (Justice et al. 2002). The MODIS Land team (MODLAND) is responsible for the development of algorithms for operationally producing 16 geophysical land data products. In this chapter, we discuss the development of vegetation green leaf area index (LAI) and the fraction of photosynthetically active radiation (400-700 nm) absorbed by vegetation (FPAR) products. LAI is defined as the one-sided green leaf area per unit ground area in broadleaf canopies, and as half the total needle surface area per unit ground area in coniferous canopies. These products are essential for studies of the exchange of fluxes of energy, mass (e.g., water and CO2), and momentum between the surface and atmosphere (Bonan et al. 2003; Dickinson et al. 1986; Potter et al. 1993; Tian et al. 2003).

  11. Mathematical models and specific absorbed fractions of photon energy in the nonpregnant adult female and at the end of each trimester of pregnancy

    SciTech Connect

    Stabin, M.G.; Watson, E.E.; Cristy, M.; Ryman, J.C.; Eckerman, K.F.; Davis, J.L.; Marshall, D.; Gehlen, M.K.

    1995-05-08

    Mathematical phantoms representing the adult female at three, six, and nine months of gestation are described. They are modifications of the 15-year-old male/adult female phantom (15-AF phantom) of Cristy and Eckerman (1987). The model of uterine contents includes the fetus, fetal skeleton, and placenta. The model is suitable for dose calculations for the fetus as a whole; individual organs within the fetus (other than the skeleton) are not modeled. A new model for the nonpregnant adult female is also described, comprising (1) the 15-AF phantom; (2) an adjustment to specific absorbed fractions for organ self-dose from photons to better match Reference Woman masses; and (3) computation of specific absorbed fractions with Reference Woman masses from ICRP Publication 23 for both penetrating and nonpenetrating radiations. Specific absorbed fractions for photons emitted from various source regions are tabulated for the new non;pregnant adult female model and the three pregnancy models.

  12. Evaluation of absorbed doses in voxel-based and simplified models for small animals.

    PubMed

    Mohammadi, Akram; Kinase, Sakae; Saito, Kimiaki

    2012-07-01

    Internal dosimetry in non-human biota is desirable from the viewpoint of radiation protection of the environment. The International Commission on Radiological Protection (ICRP) proposed Reference Animals and Plants using simplified models, such as ellipsoids and spheres and calculated absorbed fractions (AFs) for whole bodies. In this study, photon and electron AFs in whole bodies of voxel-based rat and frog models have been calculated and compared with AFs in the reference models. It was found that the voxel-based and the reference frog (or rat) models can be consistent for the whole-body AFs within a discrepancy of 25%, as the source was uniformly distributed in the whole body. The specific absorbed fractions (SAFs) and S values were also evaluated in whole bodies and all organs of the voxel-based frog and rat models as the source was distributed in the whole body or skeleton. The results demonstrated that the whole-body SAFs reflect SAFs of all individual organs as the source was uniformly distributed per mass within the whole body by about 30% uncertainties with exceptions for body contour (up to -40%) for both electrons and photons due to enhanced radiation leakages, and for the skeleton for photons only (up to +185%) due to differences in the mass attenuation coefficients. For nuclides such as (90)Y and (90)Sr, which were concentrated in the skeleton, there were large differences between S values in the whole body and those in individual organs, however the whole-body S values for the reference models with the whole body as the source were remarkably similar to those for the voxel-based models with the skeleton as the source, within about 4 and 0.3%, respectively. It can be stated that whole-body SAFs or S values in simplified models without internal organs are not sufficient for accurate internal dosimetry because they do not reflect SAFs or S values of all individual organs as the source was not distributed uniformly in whole body. Thus, voxel-based models

  13. Software Design Document SAF Workstation. Volume 1, Sections 1.0 - 2.4. 3.4.86

    DTIC Science & Technology

    1991-06-01

    Called by: OPS- BUTON >saf>ui>opord.lisp SUBPARAGRAPH >saf>ui>opord.lisp Description: None 2.2.2.1.9 PARAGRAPH Definition 9 >saf>ui>opord.lisp Type...PREVIOUS- BUTON -BOX* >saf>ui>opord.lisp Called by: None Description: None 2.2.2.1.27 (COM-SELECT-SUBPARAGRAPH) Definition 27 >saf>ui>opord.lisp Type

  14. Fractional absorption of active absorbable algal calcium (AAACa) and calcium carbonate measured by a dual stable-isotope method

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With the use of stable isotopes, this study aimed to compare the bioavailability of active absorbable algal calcium (AAACa), obtained from oyster shell powder heated to a high temperature, with an additional heated seaweed component (Heated Algal Ingredient, HAI), with that of calcium carbonate. In ...

  15. ModSAF Software Architecture Design and Overview Document

    DTIC Science & Technology

    1993-12-20

    TERMS 15. NUMBER OF PAGES Modular Semi- Automated Forces, DIS, ADST, BDS-D Approx 100 16. PRICE CODE 17. SECURITY CLASSIFICATION 17. SECURITY...3 2.1.1 Semi- Automated Forces ................................... 3 2.1.2 The SAFSim SAFstation and...103 7.. huhs.................0 I I U Chapter 1: Overview I Overview Modular Semi- Automated Forces (ModSAF) is a Computer Generated Forces (CGF

  16. Evaluation of beta-absorbed fractions in a mouse model for 90Y, 188Re, 166Ho, 149Pm, 64Cu, and 177Lu radionuclides.

    PubMed

    Miller, William H; Hartmann-Siantar, Christine; Fisher, Darrell; Descalle, Marie-Anne; Daly, Tom; Lehmann, Joerg; Lewis, Michael R; Hoffman, Timothy; Smith, Jeff; Situ, Peter D; Volkert, Wynn A

    2005-08-01

    Several short-lived, high-energy beta emitters are being proposed as the radionuclide components for molecular- targeted potential cancer therapeutic agents. The laboratory mice used to determine the efficacy of these new agents have organs that are relatively small compared to the ranges of these high-energy particles. The dosimetry model developed by Hui et al. was extended to provide realistic beta-dose estimates for organs in mice that received therapeutic radiopharmaceuticals containing (90)Y, (188)Re, (166)Ho, (149)Pm, (64)Cu, and (177)Lu. Major organs in this model included the liver, spleen, kidneys, lungs, heart, stomach, small and large bowel, thyroid, pancreas, bone, marrow, carcass, and a 0.025-g tumor. The study as reported in this paper verifies their results for (90)Y and extends them by using their organ geometry factors combined with newly calculated organ self-absorbed fractions from PEREGRINE and MCNP. PEREGRINE and MCNP agree to within 8% for the worst-case organ with average differences (averaged over all organs) decreasing from 5% for (90)Y to 1% for (177)Lu. When used with typical biodistribution data, the three different models predict doses that are in agreement to within 5% for the worst-case organ. The beta-absorbed fractions and cross-organ-deposited energy provided in this paper can be used by researchers to predict mouse-organ doses and should contribute to an improved understanding of the relationship between dose and radiation toxicity in mouse models where use of these isotopes is favorable.

  17. Evaluation of Beta-Absorbed Fractions in a Mouse Model for 90Y, 188Re, 166Ho, 149Pm, 64Cu, and 177Lu Radionuclides

    SciTech Connect

    Miller, William H.; Hartmann-Siantar, Christine; Fisher, Darrell R.; Descalle, Marie-Anne; Daly, Tom; Lehmann, Joerg; Lewis, Michael R.; Hoffman, Timothy J.; Smith, Jeff; Situ, Peter D.; Volkert, Wynn A.

    2005-08-01

    Several short-lived, high-energy beta emitters are being proposed as the radionuclide components for molecular-targeted potential cancer therapeutic agents. The laboratory mice used to determine the efficacy of these new agents have organs that are relatively small compared to the ranges of these high-energy particles. The dosimetry model developed by Hui et al. was extended to provide realistic beta-dose estimates for organs in mice that received therapeutic radiopharmaceuticals containing 90Y, 188Re, 166Ho, 149Pm, 64Cu, and 177 Lu. Major organs in this model included the liver, spleen, kidneys, lungs, heart, stomach, small and large bowel, thyroid, pancreas, bone, marrow, carcass, and a 0.025-g tumor. The study as reported in this paper verifies their results for 90Y and extends them by using their organ geometry factors combined with newly calculated organ self-absorbed fractions from PEREGRINE and MCNP. PEREGRINE and MCNP agree to within 8% for the worst-case organ with average differences (averaged over all organs) decreasing from 5% for 90Y to 1% for 177Lu. When used with typical biodistribution data, the three different models predict doses that are in agreement to within 5% for the worst-case organ. The beta-absorbed fractions and cross-organ-deposited energy provided in this paper can be used by researchers to predict mouse-organ doses and should contribute to an improved understanding of the relationship between dose and radiation toxicity in mouse models where use of these isotopes is favorable.

  18. Specific absorbed fractions from the image-based VIP-Man body model and EGS4-VLSI Monte Carlo code: internal electron emitters

    NASA Astrophysics Data System (ADS)

    Chao, T. C.; Xu, X. G.

    2001-04-01

    VIP-Man is a whole-body anatomical model newly developed at Rensselaer from the high-resolution colour images of the National Library of Medicine's Visible Human Project. This paper summarizes the use of VIP-Man and the Monte Carlo method to calculate specific absorbed fractions from internal electron emitters. A specially designed EGS4 user code, named EGS4-VLSI, was developed to use the extremely large number of image data contained in the VIP-Man. Monoenergetic and isotropic electron emitters with energies from 100 keV to 4 MeV are considered to be uniformly distributed in 26 organs. This paper presents, for the first time, results of internal electron exposures based on a realistic whole-body tomographic model. Because VIP-Man has many organs and tissues that were previously not well defined (or not available) in other models, the efforts at Rensselaer and elsewhere bring an unprecedented opportunity to significantly improve the internal dosimetry.

  19. SAF-BRET-FMEF: a developmental LMR fuel cycle facility

    SciTech Connect

    Stradley, J.G.; Yook, H.R.; Gerber, E.W.; Lerch, R.E.; Rice, L.H.

    1985-01-01

    The SAF-BRET-FMEF complex represents a versatile fuel cycle facility for processing LMR fuel. While originally conceived for processing FFTF and CRBRP fuel, it represents a facility where LMR fuel from the first generation of innovative LMRs could be processed. The cost of transporting fuel from the LMR to the Hanford site would have to be assessed when the LMR site is identified. The throughput of BRET was set at 15 MTHM/yr during conceptual design of the facility, a rate which was adequate to process all of the fuel from FFTF and fuel and blanket material from CRBRP. The design is currently being reevaluated to see if BRET could be expanded to approx.35 MTHM/yr to process fuel and blanket material from approx.1300 MWe generating capacity of the innovative LMRs. This expanded throughput is possible by designing the equipment for an instantaneous throughput of 0.2 MTHM/d, and by selected additional modifications to the facility (e.g., expansion of shipping and receiving area, and addition of a second entry tunnel transporter), and by the fact that the LMR fuel assemblies contain more fuel than the FFTF assemblies (therefore, fewer assemblies must be handled for the same throughput). The estimated cost of such an expansion is also being assessed. As stated previously, the throughput of SAF and Fuel Assembly could be made to support typical LMRs at little additional cost. The throughput could be increased to support the fuel fabrication requirements for 1300 MWe generating capacity of the innovative LMRs. This added capacity may be achieved by increasing the number of operating shifts, and is affected by variables such as fuel design, fuel enrichment, and plutonium isotopic composition.

  20. TEM Analyses of Synthetic Anti-Ferromagnetic (SAF) Nanoparticles Fabricated Using Different Release Layers

    PubMed Central

    Koh, Ai Leen; Hu, Wei; Wilson, Robert John; Wang, Shan Xiang; Sinclair, Robert

    2008-01-01

    This paper investigates the structural characteristics of templated synthetic anti-ferromagnetic (SAF) magnetic nanoparticles fabricated on two different release layers. When copper was used as the latter, the layered structure of the SAFs was found to be disrupted with wavy multi-layers due to the formation of copper grains from the release layer. By introducing oxygen into the copper release layer before the deposition of the film, the topography of the oxidized-copper grains was effectively controlled. This led to the fabrication of SAF nanoparticles with flat multi-layers. PMID:18672328

  1. Dual-rod Cr: LiSAF oscillator/amplifier for remote sensing applications

    NASA Technical Reports Server (NTRS)

    Early, J. W.; Lester, C. S.; Cockroft, N. J.; Johnson, Christyl C.; Reichle, D. J.; Mordaunt, D. W.

    1996-01-01

    A dual rod configuration is used to achieve 16W average power operation from a flashlamp-pumped Cr:LiSAF laser oscillator. A double-pass dual-rod amplifier configuration was used to amplify 141(mu)J pulses from a Q-switched diode-pumped LiSAF oscillator by a factor of (approximately)120. This experiment established a small signal gain of 13.4% per cm at 820 nm. Improved slope efficiency (7.4% electrical-to-light) and pulse repetition frequency (40Hz) were achieved with a single-rod oscillator using improved Cr:LiSAF material.

  2. Comparison of Prevalence- and Smoking Impact Ratio-Based Methods of Estimating Smoking-Attributable Fractions of Deaths

    PubMed Central

    Kong, Kyoung Ae; Jung-Choi, Kyung-Hee; Lim, Dohee; Lee, Hye Ah; Lee, Won Kyung; Baik, Sun Jung; Park, Su Hyun; Park, Hyesook

    2016-01-01

    Background Smoking is a major modifiable risk factor for premature mortality. Estimating the smoking-attributable burden is important for public health policy. Typically, prevalence- or smoking impact ratio (SIR)-based methods are used to derive estimates, but there is controversy over which method is more appropriate for country-specific estimates. We compared smoking-attributable fractions (SAFs) of deaths estimated by these two methods. Methods To estimate SAFs in 2012, we used several different prevalence-based approaches using no lag and 10- and 20-year lags. For the SIR-based method, we obtained lung cancer mortality rates from the Korean Cancer Prevention Study (KCPS) and from the United States-based Cancer Prevention Study-II (CPS-II). The relative risks for the diseases associated with smoking were also obtained from these cohort studies. Results For males, SAFs obtained using KCPS-derived SIRs were similar to those obtained using prevalence-based methods. For females, SAFs obtained using KCPS-derived SIRs were markedly greater than all prevalence-based SAFs. Differences in prevalence-based SAFs by time-lag period were minimal among males, but SAFs obtained using longer-lagged prevalence periods were significantly larger among females. SAFs obtained using CPS-II-based SIRs were lower than KCPS-based SAFs by >15 percentage points for most diseases, with the exceptions of lung cancer and chronic obstructive pulmonary disease. Conclusions SAFs obtained using prevalence- and SIR-based methods were similar for males. However, neither prevalence-based nor SIR-based methods resulted in precise SAFs among females. The characteristics of the study population should be carefully considered when choosing a method to estimate SAF. PMID:26477995

  3. Monte Carlo MCNP-4B energy absorbed fractions in Head and Brain calculated in "The ORNL mathematical phantom series" and in "MIRD 15" mathematical phantoms

    NASA Astrophysics Data System (ADS)

    Valle, Saúl H.; Lorenzo, Daniel M.; Gual, Maritza R.

    2002-08-01

    Due to the use of many new radiopharmaceuticals in Brain imaging there exists the need of predicting absorbed energy and doses during the irradiation process within the head specificity in brain. In order to evaluate the MCNP-4b capability of calculating absorbed energy in Brain and Head we calculated it first using the geometrical data from "The ORNL mathematical phantom series" and subsequently a more anthropomorphic model "current MIRD 15". The results are compared with validated data and the conclusions are shown at the end.

  4. Phosphorylation of SAF-A/hnRNP-U Serine 59 by Polo-Like Kinase 1 Is Required for Mitosis.

    PubMed

    Douglas, Pauline; Ye, Ruiqiong; Morrice, Nicholas; Britton, Sébastien; Trinkle-Mulcahy, Laura; Lees-Miller, Susan P

    2015-08-01

    Scaffold attachment factor A (SAF-A), also called heterogenous nuclear ribonuclear protein U (hnRNP-U), is phosphorylated on serine 59 by the DNA-dependent protein kinase (DNA-PK) in response to DNA damage. Since SAF-A, DNA-PK catalytic subunit (DNA-PKcs), and protein phosphatase 6 (PP6), which interacts with DNA-PKcs, have all been shown to have roles in mitosis, we asked whether DNA-PKcs phosphorylates SAF-A in mitosis. We show that SAF-A is phosphorylated on serine 59 in mitosis, that phosphorylation requires polo-like kinase 1 (PLK1) rather than DNA-PKcs, that SAF-A interacts with PLK1 in nocodazole-treated cells, and that serine 59 is dephosphorylated by protein phosphatase 2A (PP2A) in mitosis. Moreover, cells expressing SAF-A in which serine 59 is mutated to alanine have multiple characteristics of aberrant mitoses, including misaligned chromosomes, lagging chromosomes, polylobed nuclei, and delayed passage through mitosis. Our findings identify serine 59 of SAF-A as a new target of both PLK1 and PP2A in mitosis and reveal that both phosphorylation and dephosphorylation of SAF-A serine 59 by PLK1 and PP2A, respectively, are required for accurate and timely exit from mitosis.

  5. Effect of weight fraction of carbon black and number of plies of E-glass fiber to reflection loss of E-glass/ripoxy composite for radar absorbing structure (RAS)

    NASA Astrophysics Data System (ADS)

    Widyastuti, Ramadhan, Rizal; Ardhyananta, Hosta; Zainuri, Mochamad

    2013-09-01

    Nowadays, studies on investigating radar absorbing structure (RAS) using fiber reinforced polymeric (FRP) composite materials are becoming popular research field because the electromagnetic properties of FRP composites can be tailored effectively by just adding some electromagnetic powders, such as carbon black, ferrite, carbonyl iron, and etc., to the matrix of composites. The RAS works not only as a load bearing structure to hold the antenna system, but also has the important function of absorbing the in-band electromagnetic wave coming from the electromagnetic energy of tracking systems. In this study, E-glass fiber reinforced ripoxy resin composite was fabricated by blending the conductive carbon black (Ketjenblack EC300J) with the binder matrix of the composite material and maximizing the coefficient of absorption more than 90% (more than -10 dB) within the X-band frequency (8 - 12 GHz). It was measured by electrical conductivity (LCR meter) and vector network analyzer (VNA). Finally, the composite RAS with 0.02 weight fraction of carbon black and 4 plies of E-glass fiber showed thickness of 2.1 mm, electrical conductivity of 8.33 × 10-6 S/m, and maximum reflection loss of -27.123 dB, which can absorb more than 90% of incident EM wave throughout the entire X-band frequency range, has been developed.

  6. Drosophila SAF-B Links the Nuclear Matrix, Chromosomes, and Transcriptional Activity

    PubMed Central

    Alfonso-Parra, Catalina; Maggert, Keith A.

    2010-01-01

    Induction of gene expression is correlated with alterations in nuclear organization, including proximity to other active genes, to the nuclear cortex, and to cytologically distinct domains of the nucleus. Chromosomes are tethered to the insoluble nuclear scaffold/matrix through interaction with Scaffold/Matrix Attachment Region (SAR/MAR) binding proteins. Identification and characterization of proteins involved in establishing or maintaining chromosome-scaffold interactions is necessary to understand how the nucleus is organized and how dynamic changes in attachment are correlated with alterations in gene expression. We identified and characterized one such scaffold attachment factor, a Drosophila homolog of mammalian SAF-B. The large nuclei and chromosomes of Drosophila have allowed us to show that SAF-B inhabits distinct subnuclear compartments, forms weblike continua in nuclei of salivary glands, and interacts with discrete chromosomal loci in interphase nuclei. These interactions appear mediated either by DNA-protein interactions, or through RNA-protein interactions that can be altered during changes in gene expression programs. Extraction of soluble nuclear proteins and DNA leaves SAF-B intact, showing that this scaffold/matrix-attachment protein is a durable component of the nuclear matrix. Together, we have shown that SAF-B links the nuclear scaffold, chromosomes, and transcriptional activity. PMID:20422039

  7. Satellite-based surface solar radiation data provided by CM SAF - Solar energy applications

    NASA Astrophysics Data System (ADS)

    Trentmann, Jörg; Müller, Richard W.; Posselt, Rebekka; Stöckli, Reto

    2013-04-01

    The planning of solar power plants requires accurate estimates of the solar energy available at the surface. Satellite observations provide useful information on the cloud coverage, which is one of the main factors modulating the solar surface radiation. This information can be used to estimate the solar surface radiation from satellite. Observations from geostationary satellites allow the retrieval of the surface solar radiation with high temporal (up to hourly) and spatial (approx. 5 km) resolution. The EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) is deriving surface solar radiation from geostationary and polar-orbiting satellite instruments. While CM SAF is focusing on the generation of high-quality long-term climate data records, also operationally data is provided in short time latency within 8 weeks. CM SAF has already released one data set based on geostationary Meteosat satellite covering 1983 to 2005 (doi: 10.5676/EUM_SAF_CM/RAD_MVIRI/V001) and one global data set based on measurements of the polar-orbiting AVHRR instruments covering 1982 to 2009 (doi: 10.5676/EUM_SAF_CM/CLARA_AVHRR/V001). Here, we present details and applications of the CM SAF surface radiation data generated from the observations of the geostationary Meteosat satellites. The climate data set is available at high spatial (0.03 x 0.03 deg) and temporal (hourly, daily, monthly) resolutions. Besides global radiation, also the direct beam component is provided, which is for instance required for the estimation of the energy generated by solar thermal plants. Based on comparisons with surface observations the accuracy of CM SAF surface solar radiation data is better than 10 W/m2 on a monthly basis and 25 W/m2 on a daily basis. The data sets are well documented (incl. validation using surface observations) and available in netcdf-format at no cost without restrictions at www.cmsaf.eu. Solar energy applications of the data include the Photovoltaic Geographical

  8. Sound Absorbers

    NASA Astrophysics Data System (ADS)

    Fuchs, H. V.; Möser, M.

    Sound absorption indicates the transformation of sound energy into heat. It is, for instance, employed to design the acoustics in rooms. The noise emitted by machinery and plants shall be reduced before arriving at a workplace; auditoria such as lecture rooms or concert halls require a certain reverberation time. Such design goals are realised by installing absorbing components at the walls with well-defined absorption characteristics, which are adjusted for corresponding demands. Sound absorbers also play an important role in acoustic capsules, ducts and screens to avoid sound immission from noise intensive environments into the neighbourhood.

  9. Can a Satellite-Derived Estimate of the Fraction of PAR Absorbed by Chlorophyll (FAPAR(sub chl)) Improve Predictions of Light-Use Efficiency and Ecosystem Photosynthesis for a Boreal Aspen Forest?

    NASA Technical Reports Server (NTRS)

    Zhang, Qingyuan; Middleton, Elizabeth M.; Margolis, Hank A.; Drolet, Guillaume G.; Barr, Alan A.; Black, T. Andrew

    2009-01-01

    Gross primary production (GPP) is a key terrestrial ecophysiological process that links atmospheric composition and vegetation processes. Study of GPP is important to global carbon cycles and global warming. One of the most important of these processes, plant photosynthesis, requires solar radiation in the 0.4-0.7 micron range (also known as photosynthetically active radiation or PAR), water, carbon dioxide (CO2), and nutrients. A vegetation canopy is composed primarily of photosynthetically active vegetation (PAV) and non-photosynthetic vegetation (NPV; e.g., senescent foliage, branches and stems). A green leaf is composed of chlorophyll and various proportions of nonphotosynthetic components (e.g., other pigments in the leaf, primary/secondary/tertiary veins, and cell walls). The fraction of PAR absorbed by whole vegetation canopy (FAPAR(sub canopy)) has been widely used in satellite-based Production Efficiency Models to estimate GPP (as a product of FAPAR(sub canopy)x PAR x LUE(sub canopy), where LUE(sub canopy) is light use efficiency at canopy level). However, only the PAR absorbed by chlorophyll (a product of FAPAR(sub chl) x PAR) is used for photosynthesis. Therefore, remote sensing driven biogeochemical models that use FAPAR(sub chl) in estimating GPP (as a product of FAPAR(sub chl x PAR x LUE(sub chl) are more likely to be consistent with plant photosynthesis processes.

  10. Response functions for computing absorbed dose to skeletal tissues from neutron irradiation.

    PubMed

    Bahadori, Amir A; Johnson, Perry; Jokisch, Derek W; Eckerman, Keith F; Bolch, Wesley E

    2011-11-07

    Spongiosa in the adult human skeleton consists of three tissues-active marrow (AM), inactive marrow (IM) and trabecularized mineral bone (TB). AM is considered to be the target tissue for assessment of both long-term leukemia risk and acute marrow toxicity following radiation exposure. The total shallow marrow (TM(50)), defined as all tissues lying within the first 50 µm of the bone surfaces, is considered to be the radiation target tissue of relevance for radiogenic bone cancer induction. For irradiation by sources external to the body, kerma to homogeneous spongiosa has been used as a surrogate for absorbed dose to both of these tissues, as direct dose calculations are not possible using computational phantoms with homogenized spongiosa. Recent micro-CT imaging of a 40 year old male cadaver has allowed for the accurate modeling of the fine microscopic structure of spongiosa in many regions of the adult skeleton (Hough et al 2011 Phys. Med. Biol. 56 2309-46). This microstructure, along with associated masses and tissue compositions, was used to compute specific absorbed fraction (SAF) values for protons originating in axial and appendicular bone sites (Jokisch et al 2011 Phys. Med. Biol. 56 6857-72). These proton SAFs, bone masses, tissue compositions and proton production cross sections, were subsequently used to construct neutron dose-response functions (DRFs) for both AM and TM(50) targets in each bone of the reference adult male. Kerma conditions were assumed for other resultant charged particles. For comparison, AM, TM(50) and spongiosa kerma coefficients were also calculated. At low incident neutron energies, AM kerma coefficients for neutrons correlate well with values of the AM DRF, while total marrow (TM) kerma coefficients correlate well with values of the TM(50) DRF. At high incident neutron energies, all kerma coefficients and DRFs tend to converge as charged-particle equilibrium is established across the bone site. In the range of 10 eV to 100 Me

  11. SAF (Secure Automated Fabrication). Phase I interim report: a systems analysis. [LMFBR

    SciTech Connect

    Aitken, E. A.

    1981-01-01

    The current breeder reactor fuel assembly is a high quality, proven fuel that is currently manually fabricated using glovebox technology. To provide improved fuel fabrication processes, and to assure meeting increasingly stringent health and safety criteria, an advanced Secure Automated Fabrication (SAF) System is being developed for mixed uranium and plutonium fuel fabrication. SAF System development will ultimately result in systems which maximize personnel radiation protection, restrict and control access to SNM material, improve containment and detection systems for nuclear materials, provide adequate SNM accountability and improve product uniformity and quality. A systems requirement analysis study was initiated to establish the consistent and objective set of requirements within which the choice among alternatives represents the balanced veiwpoints of performance, achievability and risk.

  12. Analysis of Leaf Area Index and Fraction of PAR Absorbed by Vegetation Products from the Terra MODIS Sensor: 2000-2005

    NASA Technical Reports Server (NTRS)

    Yang, Wenze; Huang, Dong; Tan, Bin; Stroeve, Julienne C.; Shabanov, Nikolay V.; Knyazikhin, Yuri; Nemani, Ramakrishna R.; Myneni, Ranga B.

    2006-01-01

    The analysis of two years of Collection 3 and five years of Collection 4 Terra Moderate Resolution Imaging Spectroradiometer (MODIS) Leaf Area Index (LAI) and Fraction of Photosynthetically Active Radiation (FPAR) data sets is presented in this article with the goal of understanding product quality with respect to version (Collection 3 versus 4), algorithm (main versus backup), snow (snow-free versus snow on the ground), and cloud (cloud-free versus cloudy) conditions. Retrievals from the main radiative transfer algorithm increased from 55% in Collection 3 to 67% in Collection 4 due to algorithm refinements and improved inputs. Anomalously high LAI/FPAR values observed in Collection 3 product in some vegetation types were corrected in Collection 4. The problem of reflectance saturation and too few main algorithm retrievals in broadleaf forests persisted in Collection 4. The spurious seasonality in needleleaf LAI/FPAR fields was traced to fewer reliable input data and retrievals during the boreal winter period. About 97% of the snow covered pixels were processed by the backup Normalized Difference Vegetation Index-based algorithm. Similarly, a majority of retrievals under cloudy conditions were obtained from the backup algorithm. For these reasons, the users are advised to consult the quality flags accompanying the LAI and FPAR product.

  13. Assessing Perceptions of Knowledge Management Maturity/Capabilities: A Case Study of SAF/FM

    DTIC Science & Technology

    2007-03-01

    an individual, program, or event ( Leedy & Ormrod , 2005). This research is focusing on the maturity/capabilities of the SAF/FM KM program. As such...the data ( Leedy & Ormrod , 2005). This research will use pattern-matching to increase its internal validity. The pattern-matching technique was...which the case study’s results apply to situations beyond the study itself ( Leedy & Ormrod , 2005). Specifically, external validity refers to whether

  14. The self-adjusting file (SAF) system: An evidence-based update

    PubMed Central

    Metzger, Zvi

    2014-01-01

    Current rotary file systems are effective tools. Nevertheless, they have two main shortcomings: They are unable to effectively clean and shape oval canals and depend too much on the irrigant to do the cleaning, which is an unrealistic illusionThey may jeopardize the long-term survival of the tooth via unnecessary, excessive removal of sound dentin and creation of micro-cracks in the remaining root dentin. The new Self-adjusting File (SAF) technology uses a hollow, compressible NiTi file, with no central metal core, through which a continuous flow of irrigant is provided throughout the procedure. The SAF technology allows for effective cleaning of all root canals including oval canals, thus allowing for the effective disinfection and obturation of all canal morphologies. This technology uses a new concept of cleaning and shaping in which a uniform layer of dentin is removed from around the entire perimeter of the root canal, thus avoiding unnecessary excessive removal of sound dentin. Furthermore, the mode of action used by this file system does not apply the machining of all root canals to a circular bore, as do all other rotary file systems, and does not cause micro-cracks in the remaining root dentin. The new SAF technology allows for a new concept in cleaning and shaping root canals: Minimally Invasive 3D Endodontics. PMID:25298639

  15. The School Assessment for Environmental Typology (SAfETy): An Observational Measure of the School Environment.

    PubMed

    Bradshaw, Catherine P; Milam, Adam J; Furr-Holden, C Debra M; Johnson, Sarah Lindstrom

    2015-12-01

    School safety is of great concern for prevention researchers, school officials, parents, and students, yet there are a dearth of assessments that have operationalized school safety from an organizational framework using objective tools and measures. Such a tool would be important for deriving unbiased assessments of the school environment, which in turn could be used as an evaluative tool for school violence prevention efforts. The current paper presents a framework for conceptualizing school safety consistent with Crime Prevention through Environmental Design (CPTED) model and social disorganization theory, both of which highlight the importance of context as a driver for adolescents' risk for involvement in substance use and violence. This paper describes the development of a novel observational measure, called the School Assessment for Environmental Typology (SAfETy), which applies CPTED and social disorganizational frameworks to schools to measure eight indicators of school physical and social environment (i.e., disorder, trash, graffiti/vandalism, appearance, illumination, surveillance, ownership, and positive behavioral expectations). Drawing upon data from 58 high schools, we provide preliminary data regarding the validity and reliability of the SAfETy and describe patterns of the school safety indicators. Findings demonstrate the reliability and validity of the SAfETy and are discussed with regard to the prevention of violence in schools.

  16. The self-adjusting file (SAF) system: An evidence-based update.

    PubMed

    Metzger, Zvi

    2014-09-01

    Current rotary file systems are effective tools. Nevertheless, they have two main shortcomings: They are unable to effectively clean and shape oval canals and depend too much on the irrigant to do the cleaning, which is an unrealistic illusionThey may jeopardize the long-term survival of the tooth via unnecessary, excessive removal of sound dentin and creation of micro-cracks in the remaining root dentin. The new Self-adjusting File (SAF) technology uses a hollow, compressible NiTi file, with no central metal core, through which a continuous flow of irrigant is provided throughout the procedure. The SAF technology allows for effective cleaning of all root canals including oval canals, thus allowing for the effective disinfection and obturation of all canal morphologies. This technology uses a new concept of cleaning and shaping in which a uniform layer of dentin is removed from around the entire perimeter of the root canal, thus avoiding unnecessary excessive removal of sound dentin. Furthermore, the mode of action used by this file system does not apply the machining of all root canals to a circular bore, as do all other rotary file systems, and does not cause micro-cracks in the remaining root dentin. The new SAF technology allows for a new concept in cleaning and shaping root canals: Minimally Invasive 3D Endodontics.

  17. EUMETSAT and OSI-SAF Sea Surface Temperature: Recent results and future developments

    NASA Astrophysics Data System (ADS)

    O'Carroll, Anne; Le Borgne, Pierre

    2014-05-01

    The European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) delivers operational weather and climate-related satellite data, images and products throughout all day and year. EUMETSAT also has commitments to operational oceanography and atmospheric composition monitoring. Activities over the next twenty years include the continuation of the Mandatory Programmes (MSG, EPS) and future (MTG, EPS-SG), which all include ocean observations of Sea Surface Temperature. The EUMETSAT Ocean and Sea-ice (OSI) Satellite Application Facility (SAF) is lead by Meteo-France with a consortium of institutes from EUMETSAT member states, and provides reliable and timely operational services related to meteorology, oceanography and the marine environment. The OSI-SAF delivers level-2 Sea Surface Temperature products in GHRSST format from a range of EUMETSAT data including Metop AVHRR, IASI; and SEVIRI. EUMETSAT is participating in Copernicus Sentinel-3 in partnership with ESA, where EUMETSAT will operate the satellite and will serve the marine user community. The operational Sea Surface Temperature product delivered by EUMETSAT for Sentinel-3 SLSTR will be in GHRSST L2P format. On-going work towards access to relevant data from third-parties with the preparation of agreements with ISRO, SOA and JAXA, will give EUMETSAT access to an enhanced ocean products catalogue. The presentation will give an overview of activities relating to Sea Surface Temperature at EUMETSAT and the OSI-SAF, and their support to GHRSST, focusing on recent results and future developments.

  18. Reference values for the production of the aqueous fraction of the tear film measured by the standardized endodontic absorbent paper point test in different exotic and laboratory animal species.

    PubMed

    Lange, Rogério R; Lima, Leandro; Przydzimirski, Andreise C; Montiani-Ferreira, Fabiano

    2014-01-01

    The aqueous fraction of the tear film and the horizontal palpebral fissure length (HPFL) were measured in exotic and laboratory animals, specifically saffron finches (Sicalis flaveola), chestnut-bellied seed-finches (Sporophila angolensis), red-eared sliders (Trachemys scripta elegans), rats (Rattus norvegicus) and mice (Mus musculus). These species possess small eyes making it difficult to perform the typical Schirmer tear test. Measurement of the aqueous fraction of the tear was performed using the standardized endodontic absorbent paper point tear test (PPTT), accomplished with manual restraint by a single operator. The following results were obtained: saffron finches (n = 42)-HPFL (4.46 ± 0.09 mm) and PPTT (5.10 ± 0.26 mm); chestnut-bellied seed-finches (n = 38)-HPFL (4.77 ± 0.05 mm) and PPTT (4.11 ± 0.34 mm); red-eared sliders (n = 56)-HPFL (8.59 ± 0.08 mm) and PPTT (8.79 ± 0.38 mm); rats (n = 60)-HPFL (6.45 ± 0.09 mm) and PTT (6.18 ± 2.06 mm); and mice (n = 22)-HPFL (3.59 ± 0.27 mm) and PPTT (4.39 ± 1.45 mm).

  19. The validation service of the hydrological SAF geostationary and polar satellite precipitation products

    NASA Astrophysics Data System (ADS)

    Puca, S.; Porcu, F.; Rinollo, A.; Vulpiani, G.; Baguis, P.; Balabanova, S.; Campione, E.; Ertürk, A.; Gabellani, S.; Iwanski, R.; Jurašek, M.; Kaňák, J.; Kerényi, J.; Koshinchanov, G.; Kozinarova, G.; Krahe, P.; Lapeta, B.; Lábó, E.; Milani, L.; Okon, L'.; Öztopal, A.; Pagliara, P.; Pignone, F.; Rachimow, C.; Rebora, N.; Roulin, E.; Sönmez, I.; Toniazzo, A.; Biron, D.; Casella, D.; Cattani, E.; Dietrich, S.; Di Paola, F.; Laviola, S.; Levizzani, V.; Melfi, D.; Mugnai, A.; Panegrossi, G.; Petracca, M.; Sanò, P.; Zauli, F.; Rosci, P.; De Leonibus, L.; Agosta, E.; Gattari, F.

    2014-04-01

    The development phase (DP) of the EUMETSAT Satellite Application Facility for Support to Operational Hydrology and Water Management (H-SAF) led to the design and implementation of several precipitation products, after 5 yr (2005-2010) of activity. Presently, five precipitation estimation algorithms based on data from passive microwave and infrared sensors, on board geostationary and sun-synchronous platforms, function in operational mode at the H-SAF hosting institute to provide near real-time precipitation products at different spatial and temporal resolutions. In order to evaluate the precipitation product accuracy, a validation activity has been established since the beginning of the project. A Precipitation Product Validation Group (PPVG) works in parallel with the development of the estimation algorithms with two aims: to provide the algorithm developers with indications to refine algorithms and products, and to evaluate the error structure to be associated with the operational products. In this paper, the framework of the PPVG is presented: (a) the characteristics of the ground reference data available to H-SAF (i.e. radar and rain gauge networks), (b) the agreed upon validation strategy settled among the eight European countries participating in the PPVG, and (c) the steps of the validation procedures. The quality of the reference data is discussed, and the efforts for its improvement are outlined, with special emphasis on the definition of a ground radar quality map and on the implementation of a suitable rain gauge interpolation algorithm. The work done during the H-SAF development phase has led the PPVG to converge into a common validation procedure among the members, taking advantage of the experience acquired by each one of them in the validation of H-SAF products. The methodology is presented here, indicating the main steps of the validation procedure (ground data quality control, spatial interpolation, up-scaling of radar data vs. satellite grid

  20. Moving horizon estimation for assimilating H-SAF remote sensing data into the HBV hydrological model

    NASA Astrophysics Data System (ADS)

    Montero, Rodolfo Alvarado; Schwanenberg, Dirk; Krahe, Peter; Lisniak, Dmytro; Sensoy, Aynur; Sorman, A. Arda; Akkol, Bulut

    2016-06-01

    Remote sensing information has been extensively developed over the past few years including spatially distributed data for hydrological applications at high resolution. The implementation of these products in operational flow forecasting systems is still an active field of research, wherein data assimilation plays a vital role on the improvement of initial conditions of streamflow forecasts. We present a novel implementation of a variational method based on Moving Horizon Estimation (MHE), in application to the conceptual rainfall-runoff model HBV, to simultaneously assimilate remotely sensed snow covered area (SCA), snow water equivalent (SWE), soil moisture (SM) and in situ measurements of streamflow data using large assimilation windows of up to one year. This innovative application of the MHE approach allows to simultaneously update precipitation, temperature, soil moisture as well as upper and lower zones water storages of the conceptual model, within the assimilation window, without an explicit formulation of error covariance matrixes and it enables a highly flexible formulation of distance metrics for the agreement of simulated and observed variables. The framework is tested in two data-dense sites in Germany and one data-sparse environment in Turkey. Results show a potential improvement of the lead time performance of streamflow forecasts by using perfect time series of state variables generated by the simulation of the conceptual rainfall-runoff model itself. The framework is also tested using new operational data products from the Satellite Application Facility on Support to Operational Hydrology and Water Management (H-SAF) of EUMETSAT. This study is the first application of H-SAF products to hydrological forecasting systems and it verifies their added value. Results from assimilating H-SAF observations lead to a slight reduction of the streamflow forecast skill in all three cases compared to the assimilation of streamflow data only. On the other hand

  1. SAF - Sets and Fields parallel I/O and scientific data modeling system

    SciTech Connect

    Matzke, Robb; Illescas, Eric; Espen, Peter; Jones, Jake S.; Sjaardema, Gregory; Miller, Mark C.; Schoof, Larry A.; Reus, James F.; Arrighi, William; Hitt, Ray T.; O'Brien, Matthew J.

    2005-07-01

    SAF is being developed as part of the Data Models and Formats (DMF) component of the Accelerated Strategic Computing Initiative (ASCI). SAF represents a revolutionary approach to interoperation of high performance, scientific computing applications based upon rigorous, math oriented data modeling principles. Previous technologies have required all applications to use the same data structures and/or mesh objects to represent scientific data or lead to an ever expanding set of incrementally different data structures and/or mesh objects. SAF addresses this problem by providing a small set of mathematical building blocks, sets, relations and fields, out of which a wide variety of scientific data can be characterized. Applications literally model their data by assembling these building blocks. Sets and fields building blocks are at once, both primitive and abstract: * They are primitive enough to model a wide variety of scientific data. * They are abstract enough to model the data in terms of what it represents in a mathematical or physical sense independent of how it is represented in an implementation sense. For example, while there are many ways to represent the airflow over the wing of a supersonic aircraft in a computer program, there is only one mathematical/physical interpretation: a field of 3D velocity vectors over a 2D surface. This latter description is immutable. It is independent of any particular representation or implementation choices. Understanding this what versus how relationship, that is what is represented versus how it is represented, is key to developing a solution for large scale integration of scientific software.

  2. Explication of Definitional Description and Empirical Use of Fraction of Orally Administered Drugs Absorbed From the Intestine (Fa) and Intestinal Availability (Fg): Effect of P-glycoprotein and CYP3A on Fa and Fg.

    PubMed

    Tanaka, Yuta; Kitamura, Yoshiaki; Maeda, Kazuya; Sugiyama, Yuichi

    2016-02-01

    Conventionally, it is believed that the fraction of orally administered drugs absorbed from the intestine (Fa) and intestinal availability (Fg) are independently determined by the apical membrane permeation and intestinal metabolism, respectively. However, the validity of this belief has not been well discussed, and Fa and Fg are often used without careful definition. In this review, Fa and Fg are mathematically described based on their definitions under the linear kinetics of metabolism and transport. Even considering with different models, intestinal metabolic enzymes such as cytochrome P450 3A affected both Fa and Fg, whereas apical efflux transporters including P-glycoprotein had no influence on Fg at least under the linear condition. To determine whether Fa and Fg calculated using different clinical methods are identical, empirical Fa and Fg were mathematically described based on "feces method" and "grapefruit juice method" and compared with their definitions. Fa and Fg obtained by the feces method corresponded with their definitions whereas the grapefruit juice method provided smaller Fa and larger Fg particularly for dual substrates of P-glycoprotein and cytochrome P450 3A with low membrane permeability. Our analyses suggest that the definitions and calculation methods of Fa and Fg should be considered when we intend to separately determine these values.

  3. The CM SAF ATOVS tropospheric water vapour and temperature data record: overview of methodology and evaluation

    NASA Astrophysics Data System (ADS)

    Courcoux, N.; Schröder, M.

    2015-02-01

    Recently, the reprocessed Advanced Television Infrared Observation Satellite (TIROS)-N Operational Vertical Sounder (ATOVS) tropospheric water vapour and temperature data record has been released by the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) Satellite Application Facility on Climate Monitoring (CM SAF). ATOVS observations from the National Oceanic and Atmospheric Agency (NOAA)-15 through NOAA-19 and EUMETSAT's Meteorological operational (Metop-A) satellites have been consistently reprocessed to generate 13 years (1999-2011) of global water vapour and temperature daily and monthly means with a spatial resolution of 90 km × 90 km. After pre-processing, an optimal estimation scheme has been applied to the observations to simultaneously infer temperature and water vapour profiles. In a post-processing step an objective interpolation method (Kriging) has been applied to allow for gap filling. The product suite includes total precipitable water vapour (TPW), layer integrated water vapour (LPW) and layer mean temperature for five tropospheric layers, as well as specific humidity and temperature at six tropospheric levels and is referenced under doi:SAF_CM/WVT_ATOVS/V001">10.5676/EUM_SAF_CM/WVT_ATOVS/V001. To our knowledge this is the first time that the ATOVS record (1998-now) has been consistently reprocessed (1999-2011) to retrieve water vapour and temperature products. TPW and LPW products were compared to corresponding products from the Global Climate Observing System (GCOS) Upper-Air Network (GUAN) radiosonde observations and from the Atmospheric InfraRed Sounder (AIRS) version 5 satellite data record. The TPW shows a good agreement with the GUAN radiosonde data: average bias and root mean square error (RMSE) are -0.2 and 3.3 kg m-2, respectively. The maximum absolute (relative) bias and RMSE values decrease (increase) strongly with height. While the RMSE relative to AIRS is

  4. Shape and Albedo from Shading (SAfS) for Pixel-Level dem Generation from Monocular Images Constrained by Low-Resolution dem

    NASA Astrophysics Data System (ADS)

    Wu, Bo; Chung Liu, Wai; Grumpe, Arne; Wöhler, Christian

    2016-06-01

    Lunar topographic information, e.g., lunar DEM (Digital Elevation Model), is very important for lunar exploration missions and scientific research. Lunar DEMs are typically generated from photogrammetric image processing or laser altimetry, of which photogrammetric methods require multiple stereo images of an area. DEMs generated from these methods are usually achieved by various interpolation techniques, leading to interpolation artifacts in the resulting DEM. On the other hand, photometric shape reconstruction, e.g., SfS (Shape from Shading), extensively studied in the field of Computer Vision has been introduced to pixel-level resolution DEM refinement. SfS methods have the ability to reconstruct pixel-wise terrain details that explain a given image of the terrain. If the terrain and its corresponding pixel-wise albedo were to be estimated simultaneously, this is a SAfS (Shape and Albedo from Shading) problem and it will be under-determined without additional information. Previous works show strong statistical regularities in albedo of natural objects, and this is even more logically valid in the case of lunar surface due to its lower surface albedo complexity than the Earth. In this paper we suggest a method that refines a lower-resolution DEM to pixel-level resolution given a monocular image of the coverage with known light source, at the same time we also estimate the corresponding pixel-wise albedo map. We regulate the behaviour of albedo and shape such that the optimized terrain and albedo are the likely solutions that explain the corresponding image. The parameters in the approach are optimized through a kernel-based relaxation framework to gain computational advantages. In this research we experimentally employ the Lunar-Lambertian model for reflectance modelling; the framework of the algorithm is expected to be independent of a specific reflectance model. Experiments are carried out using the monocular images from Lunar Reconnaissance Orbiter (LRO

  5. Anaerobic treatment of municipal wastewater with a staged anaerobic fluidized membrane bioreactor (SAF-MBR) system.

    PubMed

    Yoo, Rihye; Kim, Jeonghwan; McCarty, Perry L; Bae, Jaeho

    2012-09-01

    A laboratory-scale staged anaerobic fluidized membrane bioreactor (SAF-MBR) system was used to treat a municipal wastewater primary-clarifier effluent. It was operated continuously for 192 days at 6-11 L/m(2)/h flux and trans-membrane pressure generally of 0.1 bar or less with no fouling control except the scouring effect of the fluidized granular activated carbon on membrane surfaces. With a total hydraulic retention time of 2.3h at 25°C, the average effluent chemical oxygen demand and biochemical oxygen demand concentrations of 25 and 7 mg/L yielded corresponding removals of 84% and 92%, respectively. Also, near complete removal of suspended solids was obtained. Biosolids production, representing 5% of the COD removed, equaled 0.049 g VSS/g BOD(5) removed, far less than the case with comparable aerobic processes. The electrical energy required for the operation of the SAF-MBR system, 0.047 kW h/m(3), could be more than satisfied by using the methane produced.

  6. High efficiency ring-lens supercritical angle fluorescence (SAF) detection for optimum bioassay performance.

    PubMed

    Kurzbuch, Dirk; Somers, Martin; McDonagh, Colette

    2013-09-23

    We present a polymer biochip with embedded optics which allows the detection of supercritical angle fluorescence (SAF) without losses due to total internal reflection within the substrate. The chip design comprises structured spherical and aspherical optical elements on the bottom, while the top is chemically functionalized for direct binding of biomolecules. Furthermore, this design facilitates integration in lab-on-a-chip systems with appropriate microfluidics. In the confocal optical setup an ellipsoidal mirror is used for collection of SAF light above the critical angle of the water-polymer interface, which is detected by a photon-counting detector. The work presented here represents a proof of concept for performing sensitive and rapid point-of-care testing, using this low-cost, robust and disposable optical biochip platform. The performance of the platform was validated using direct binding DNA and human IgG assays which yielded low limits of detection 10 pM for DNA and 10 pg/ml for human IgG.

  7. OSI-SAF operational NPP/VIIRS sea surface temperature chain

    NASA Astrophysics Data System (ADS)

    Le Borgne, Pierre; Legendre, Gérard; Marsouin, Anne; Péré, Sonia; Roquet, Hervé

    2013-06-01

    Data of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi National Polar-orbiting Partnership (NPP) have been acquired at Centre de Météorologie Spatiale (CMS) in Lannion (Brittany) in direct readout mode since April 2012. CMS is committed to produce sea surface temperature (SST) products from VIIRS data twice a day over an area covering North-East Atlantic and the Mediterranean Sea in the framework of the EUMETSAT Ocean and Sea Ice Satellite Application Facility (OSI-SAF). A cloud mask has been developed and cloud mask control techniques have been implemented. SST algorithms have been defined, as well as quality level attribution rules. Since mid October 2012 a VIIRS SST chain, similar to that used for processing METOP AVHRR has been run in a preoperational mode. The corresponding bias and standard deviation against drifting buoy measurements (mid October 2012 to mid March 2013) are -0.05 and 0.37 K for nighttime and -0.13 and 0.46 K for daytime, respectively. VIIRS derived SST production is expected operational by mid 2013. The OSI-SAF VIIRS derived SST products are compliant with the Group for High Resolution SST (GHRSST) GDS V2.0 format.

  8. Software Design Document SAF Simulation Host CSCI (8). Volume 1, Sections 1.0 - 2.7

    DTIC Science & Technology

    1991-06-01

    simnet/src/host/version.c This CSC prints the version information when the Simhost CSCI ( phantom program) is started. Comments provide a brief...history of releases. 2.1.3.2.1 identifyversion CSU Through multiple calls to printf this CSU displays the current version ( PHANTOM 3.9.10) and date...Simhost CSCI ( phantom program) and to clear the vehicles currently being simulated. Figure 2.2-)J presents the saf.c CSC structure. saf.c Ma 8.2.4 scomple

  9. Using EO-1 Hyperion to Simulate HyspIRI Products for a Coniferous Forest: The Fraction of PAR Absorbed by Chlorophyll (fAPAR(sub chl)) and Leaf Water Content (LWC)

    NASA Technical Reports Server (NTRS)

    Zhang, Qingyuan; Middleton, Elizabeth M.; Gao, Bo-Cai; Cheng, Yen-Ben

    2011-01-01

    This study presents development of prototype products for terrestrial ecosystems in preparation for the future imaging spectrometer planned for the Hyperspectral Infrared Imager (HyspIRI) mission. We present a successful demonstration example in a coniferous forest of two product prototypes: fraction of photosynthetic active radiation (PAR) absorbed by chlorophyll of a canopy (fAPAR(sub chl)) and leaf water content (LWC), for future HyspIRI implementation at 60 m spatial resolution. For this, we used existing 30 m resolution imaging spectrometer data available from the Earth Observing One (EO-1) Hyperion satellite to simulate and prototype the level one radiometrically corrected radiance (L1R) images expected from the HyspIRI visible through shortwave infrared spectrometer. The HyspIRI-like images were atmospherically corrected to obtain surface reflectance, and spectrally resampled to produce 60 m reflectance images for wavelength regions that were comparable to all seven of the MODerate resolution Imaging Spectroradiometer (MODIS) land bands. Thus, we developed MODIS-like surface reflectance in seven spectral bands at the HyspIRI-like spatial scale, which was utilized to derive fAPARchl and LWC with a coupled canopy-leaf radiative transfer model (PROSAIL2) for the coniferous forest[1]. With this study, we provide additional evidence that the fAPARchl product is more realistic for describing the physiologically active canopy than the traditional fAPAR parameter for the whole canopy (fAPAR(sub canopy)), and thus should replace it in ecosystem process models to reduce uncertainties in terrestrial carbon cycle studies and ecosystem studies.

  10. Using EO-1 Hyperion to Simulate HyspIRI Products for a Coniferous Forest: The Fraction of PAR Absorbed by Chlorophyll (fAPAR(sub chl)) and Leaf Water Content(LWC)

    NASA Technical Reports Server (NTRS)

    Zhang, Qingyuan; Middleton, Elizabeth M.; Gao, Bo-Cai; Cheng, Yen-Ben

    2012-01-01

    This paper presents development of prototype products for terrestrial ecosystems in preparation for the future imaging spectrometer planned for the Hyperspectral Infrared Imager (HyspIRI) mission. We present a successful demonstration example in a coniferous forest of two product prototypes: fraction of photosynthetically active radiation (PAR) absorbed by chlorophyll of a canopy (fAPARchl) and leaf water content (LWC), for future HyspIRI implementation at 60-m spatial resolution. For this, we used existing 30-m resolution imaging spectrometer data available from the Earth Observing One (EO-1) Hyperion satellite to simulate and prototype the level one radiometrically corrected radiance (L1R) images expected from the HyspIRI visible through shortwave infrared spectrometer. The HyspIRIlike images were atmospherically corrected to obtain surface reflectance and spectrally resampled to produce 60-m reflectance images for wavelength regions that were comparable to all seven of the MODerate resolution Imaging Spectroradiometer (MODIS) land bands. Thus, we developed MODIS-like surface reflectance in seven spectral bands at the HyspIRI-like spatial scale, which was utilized to derive fAPARchl and LWC with a coupled canopy-leaf radiative transfer model (PROSAIL2) for the coniferous forest. With this paper, we provide additional evidence that the fAPARchl product is more realistic in describing the physiologically active canopy than the traditional fAPAR parameter for the whole canopy (fAPARcanopy), and thus, it should replace it in ecosystem process models to reduce uncertainties in terrestrial carbon cycle and ecosystem studies.

  11. Attenuation of Symbiotic Effectiveness by Rhizobium meliloti SAF22 Related to the Presence of a Cryptic Plasmid

    PubMed Central

    Velazquez, E.; Mateos, P. F.; Pedrero, P.; Dazzo, F. B.; Martinez-Molina, E.

    1995-01-01

    Several wild-type strains of Rhizobium meliloti isolated from alfalfa nodules exhibited different plasmid profiles, yet did not differ in growth rate in yeast-mannitol medium, utilization of 43 different carbon sources, intrinsic resistance to 14 antibiotics, or detection of 16 enzyme activities. In contrast, three measures of effectiveness in symbiotic nitrogen fixation with alfalfa (shoot length, dry weight, and nitrogen content) indicated that R. meliloti SAF22, whose plasmid profile differs from those of the other strains tested, is significantly less effective than other wild-type strains in symbiotic nitrogen fixation. Light microscopy of nodules infected with strain SAF22 showed an abnormal center of nitrogen fixation zone III, with bacteria occupying a smaller portion of the infected host cells and vacuoles occupying a significantly larger portion of adjacent uninfected host cells. In contrast, the effective nodules infected with other wild types or plasmid pRmSAF22c-cured segregants of SAF22 did not display this cytological abnormality. PMID:16535033

  12. Scaffold attachment factor A (SAF-A) and Ku temporally regulate repair of radiation-induced clustered genome lesions

    PubMed Central

    Mantha, Anil K.; Hegde, Pavana M.; Pandey, Arvind; Sengupta, Shiladitya; Yu, Yaping; Calsou, Patrick; Chen, David; Lees-Miller, Susan P.; Mitra, Sankar

    2016-01-01

    Ionizing radiation (IR) induces highly cytotoxic double-strand breaks (DSBs) and also clustered oxidized bases in mammalian genomes. Base excision repair (BER) of bi-stranded oxidized bases could generate additional DSBs as repair intermediates in the vicinity of direct DSBs, leading to loss of DNA fragments. This could be avoided if DSB repair via DNA-PK-mediated nonhomologous end joining (NHEJ) precedes BER initiated by NEIL1 and other DNA glycosylases (DGs). Here we show that DNA-PK subunit Ku inhibits DGs via direct interaction. The scaffold attachment factor (SAF)-A, (also called hnRNP-U), phosphorylated at Ser59 by DNA-PK early after IR treatment, is linked to transient release of chromatin-bound NEIL1, thus preventing BER. SAF-A is subsequently dephosphorylated. Ku inhibition of DGs in vitro is relieved by unphosphorylated SAF-A, but not by the phosphomimetic Asp59 mutant. We thus propose that SAF-A, in concert with Ku, temporally regulates base damage repair in irradiated cell genome. PMID:27303920

  13. Heavy metals produce toxicity, oxidative stress and apoptosis in the marine teleost fish SAF-1 cell line.

    PubMed

    Morcillo, Patricia; Esteban, María Á; Cuesta, Alberto

    2016-02-01

    The use of cell lines to test the toxicity of aquatic pollutants is a valuable alternative to fish bioassays. In this study, fibroblast SAF-1 cells from the marine gilthead seabream (Sparus aurata L.) were exposed for 24 h to the heavy metals Cd, Hg, MeHg (Methylmercury), As or Pb and the resulting cytotoxicity was assessed. Neutral red (NR), MTT-tetrazolio (MTT), crystal violet (CV) and lactate dehydrogenase (LDH) viability tests showed that SAF-1 cells exposed to the above heavy metals produced a dose-dependent reduction in the number of viable cells. Methylmercury showed the highest toxicity (EC50 = 0.01 mM) followed by As, Cd, Hg and Pb. NR was the most sensitive method followed by MTT, CV and LDH. SAF-1 cells incubated with each of the heavy metals also exhibited an increase in the production of reactive oxygen species and apoptosis cell death. Moreover, the corresponding gene expression profiles pointed to the induction of the metallothionein protective system, cellular and oxidative stress and apoptosis after heavy metal exposure for 24 h. This report describes and compares tools for evaluating the potential effects of marine contamination using the SAF-1 cell line.

  14. Femtosecond Cr:LiSAF and Cr:LiCAF lasers pumped by tapered diode lasers.

    PubMed

    Demirbas, Umit; Schmalz, Michael; Sumpf, Bernd; Erbert, Götz; Petrich, Gale S; Kolodziejski, Leslie A; Fujimoto, James G; Kärtner, Franz X; Leitenstorfer, Alfred

    2011-10-10

    We report compact, low-cost and efficient Cr:Colquiriite lasers that are pumped by high brightness tapered laser diodes. The tapered laser diodes provided 1 to 1.2 W of output power around 675 nm, at an electrical-to-optical conversion efficiency of about 30%. Using a single tapered diode laser as the pump source, we have demonstrated output powers of 500 mW and 410 mW together with slope efficiencies of 47% and 41% from continuous wave (cw) Cr:LiSAF and Cr:LiCAF lasers, respectively. In cw mode-locked operation, sub-100-fs pulse trains with average power between 200 mW and 250 mW were obtained at repetition rates around 100 MHz. Upon pumping the Cr:Colquiriite lasers with two tapered laser diodes (one from each side of the crystal), we have observed scaling of cw powers to 850 mW in Cr:LiSAF and to 650 mW in Cr:LiCAF. From the double side pumped Cr:LiCAF laser, we have also obtained ~220 fs long pulses with 5.4 nJ of pulse energy at 77 MHz repetition rate. These are the highest energy levels reported from Cr:Colquiriite so far at these repetition rates. Our findings indicate that tapered diodes in the red spectral region are likely to become the standard pump source for Cr:Colquiriite lasers in the near future. Moreover, the simplified pumping scheme might facilitate efficient commercialization of Cr:Colquiriite systems, bearing the potential to significantly boost applications of cw and femtosecond lasers in this spectral region (750-1000 nm).

  15. Effect of QPQ nitriding time on microstructure and wear resistance of SAF2906 duplex stainless steel

    NASA Astrophysics Data System (ADS)

    Liu, D.; Wu, G. X.; Shen, L. X.

    2017-01-01

    QPQ salt bath treatment of SAF2906 duplex stainless steel was conducted at 570 °C for 60 min, 90 min,120 min,150 min and 180 min, followed by post-oxidation process with heating temperature of 400°C and holding duration of 30 min. The effect of QPQ nitriding time on microstructure and wear resistance of SAF2906 duplex stainless steel was investigated by means of OM, SEM, XRD, microhardness test, adhesion strength test and wear resistance test. Microstructure observation showed outer layer was composed of Fe3O4. The main phase of the intermediate layer was CrN, αN and Fe2-3N. The main phase of the inner layer was CrN and S. The adhesion strength test of the surface layer-substrate showed the QPQ treated samples have favorable adhesion strength of HF-1 level. With the increase of nitriding time, the growth rate of the compound layer gradually slowed down and the surface hardness first increased and then decreased, and the maximum hardness was 1283 HV0.2 at 150 min. The dry siliding results showed that the wear resistance of the QPQ treated samples was at least 20 times than that of the substrate, and the optimum nitriding time to obtain the best wear resistance is 150 min. The worn surface morphology observation showed the main wear mechanism of the substrate was plough wear, while micro-cutting is the main wear mechanism that causes the damage of the QPQ treated samples.

  16. MVIRI/SEVIRI TOA Radiation Datasets within the Climate Monitoring SAF

    NASA Astrophysics Data System (ADS)

    Urbain, Manon; Clerbaux, Nicolas; Ipe, Alessandro; Baudrez, Edward; Velazquez Blazquez, Almudena; Moreels, Johan

    2016-04-01

    Within CM SAF, Interim Climate Data Records (ICDR) of Top-Of-Atmosphere (TOA) radiation products from the Geostationary Earth Radiation Budget (GERB) instruments on the Meteosat Second Generation (MSG) satellites have been released in 2013. These datasets (referred to as CM-113 and CM-115, resp. for shortwave (SW) and longwave (LW) radiation) are based on the instantaneous TOA fluxes from the GERB Edition-1 dataset. They cover the time period 2004-2011. Extending these datasets backward in the past is not possible as no GERB instruments were available on the Meteosat First Generation (MFG) satellites. As an alternative, it is proposed to rely on the Meteosat Visible and InfraRed Imager (MVIRI - from 1982 until 2004) and the Spinning Enhanced Visible and Infrared Imager (SEVIRI - from 2004 onward) to generate a long Thematic Climate Data Record (TCDR) from Meteosat instruments. Combining MVIRI and SEVIRI allows an unprecedented temporal (30 minutes / 15 minutes) and spatial (2.5 km / 3 km) resolution compared to the Clouds and the Earth's Radiant Energy System (CERES) products. This is a step forward as it helps to increase the knowledge of the diurnal cycle and the small-scale spatial variations of radiation. The MVIRI/SEVIRI datasets (referred to as CM-23311 and CM-23341, resp. for SW and LW radiation) will provide daily and monthly averaged TOA Reflected Solar (TRS) and Emitted Thermal (TET) radiation in "all-sky" conditions (no clear-sky conditions for this first version of the datasets), as well as monthly averaged of the hourly integrated values. The SEVIRI Solar Channels Calibration (SSCC) and the operational calibration have been used resp. for the SW and LW channels. For MFG, it is foreseen to replace the latter by the EUMETSAT/GSICS recalibration of MVIRI using HIRS. The CERES TRMM angular dependency models have been used to compute TRS fluxes while theoretical models have been used for TET fluxes. The CM-23311 and CM-23341 datasets will cover a 32 years

  17. Spectrophotometry of Thin Films of Light-Absorbing Particles.

    PubMed

    Binks, Bernard P; Fletcher, Paul D I; Johnson, Andrew J; Marinopoulos, Ioannis; Crowther, Jonathan M; Thompson, Michael A

    2017-04-06

    Thin films of dispersions of light-absorbing solid particles or emulsions containing a light-absorbing solute all have a nonuniform distribution of light-absorbing species throughout the sample volume. This results in nonuniform light absorption over the illuminated area, which causes the optical absorbance, as measured using a conventional specular UV-vis spectrophotometer, to deviate from the Beer-Lambert relationship. We have developed a theoretical model to account for the absorbance properties of such films, which are shown to depend on the size and volume fraction of the light-absorbing particles plus other sample variables. We have compared model predictions with measured spectra for samples consisting of emulsions containing a dissolved light-absorbing solute. Using no adjustable parameters, the model successfully predicts the behavior of nonuniform, light-absorbing emulsion films with varying values of droplet size, volume fraction, and other parameters.

  18. Thorium-229 solid-state nuclear clock prospects in MgF2 and LiSAF

    NASA Astrophysics Data System (ADS)

    Meyer, Edmund; Barker, Beau; Collins, Lee

    2016-05-01

    The 229 Th isomer is thought to be a good candidate for a nuclear clock based on its relatively low-energy isomer excitation of ~ 7 . 8 eV. We report on the study of Th atoms embedded in two crystals, MgF2 and LiSAF (LiSrAlF6). For MgF2 we perform an oxidation study to find the preferred ionization state of the Th atom in the crystal; Thn+, where n = 2 - 4 . We find that the preferred state is n = 4 which requires two interstitial Fluorine atoms to charge compensate. Using the results of MgF2 we then search within LiSAF for suitable dopant sites (the Sr, Al, or Li can all serve). Employing a standard density functional package using a plane-wave basis and psuedopotentials, we optimize a doped cell of increasing particle number sizes and use this to estimate the dilute doped-limit band-gap of LiSAF. Placement of the dopant on the Sr and Al sites with accompanying double and single F interstitial atom placements is also studied to determine the ground state, and comparisons are made with previous calculations. In both crystal ground states, we find that the band gap is large enough for the observation of the 229 Th nuclear isomer transition; > 9 eV.

  19. Compact and efficient Cr:LiSAF laser pumped by one low-cost single-spatial-mode diode

    NASA Astrophysics Data System (ADS)

    Demirbas, Umit; Eggert, Stefan; Leitenstorfer, Alfred

    2012-06-01

    We present a minimal-cost Cr:LiSAF laser that is pumped by one single-spatial-mode diode. The pumping system (diode, diode driver, and the diode holder) has a total cost of about 500 and provided 130 mW of diffraction-limited pump power around 660 nm. The entire Cr:LiSAF laser system has an estimated total material cost below 5k, a footprint of about 20 cm × 35 cm, does not require cooling and can be driven by batteries, making the system ideal for applications that require portability. In continuous wave (cw) laser experiments, we have demonstrated lasing thresholds as low as 2 mW, slope efficiencies as high as 52%, output powers up to 58 mW, and a record tuning range extending from 780 nm to 1110 nm. In cw mode-locked operation, using a 0.5% output coupler, 100-fs pulses with an average power of 38 mW, and with an optical spectrum centered around 865 nm have been obtained at a repetition rate of 235 MHz. With a more compact cavity and using a 0.1% output coupler, 70-fs pulses with an average power of 20 mW have been obtained at a repetition rate of 509 MHz. We believe that this portable, minimal cost Cr:LiSAF laser system might be an attractive source for applications like amplifier seeding that do not require high average output power levels.

  20. Composition for absorbing hydrogen

    DOEpatents

    Heung, Leung K.; Wicks, George G.; Enz, Glenn L.

    1995-01-01

    A hydrogen absorbing composition. The composition comprises a porous glass matrix, made by a sol-gel process, having a hydrogen-absorbing material dispersed throughout the matrix. A sol, made from tetraethyl orthosilicate, is mixed with a hydrogen-absorbing material and solidified to form a porous glass matrix with the hydrogen-absorbing material dispersed uniformly throughout the matrix. The glass matrix has pores large enough to allow gases having hydrogen to pass through the matrix, yet small enough to hold the particles dispersed within the matrix so that the hydrogen-absorbing particles are not released during repeated hydrogen absorption/desorption cycles.

  1. Composition for absorbing hydrogen

    DOEpatents

    Heung, L.K.; Wicks, G.G.; Enz, G.L.

    1995-05-02

    A hydrogen absorbing composition is described. The composition comprises a porous glass matrix, made by a sol-gel process, having a hydrogen-absorbing material dispersed throughout the matrix. A sol, made from tetraethyl orthosilicate, is mixed with a hydrogen-absorbing material and solidified to form a porous glass matrix with the hydrogen-absorbing material dispersed uniformly throughout the matrix. The glass matrix has pores large enough to allow gases having hydrogen to pass through the matrix, yet small enough to hold the particles dispersed within the matrix so that the hydrogen-absorbing particles are not released during repeated hydrogen absorption/desorption cycles.

  2. Digital Alloy Absorber for Photodetectors

    NASA Technical Reports Server (NTRS)

    Hill, Cory J. (Inventor); Ting, David Z. (Inventor); Gunapala, Sarath D. (Inventor)

    2016-01-01

    In order to increase the spectral response range and improve the mobility of the photo-generated carriers (e.g. in an nBn photodetector), a digital alloy absorber may be employed by embedding one (or fraction thereof) to several monolayers of a semiconductor material (insert layers) periodically into a different host semiconductor material of the absorber layer. The semiconductor material of the insert layer and the host semiconductor materials may have lattice constants that are substantially mismatched. For example, this may performed by periodically embedding monolayers of InSb into an InAsSb host as the absorption region to extend the cutoff wavelength of InAsSb photodetectors, such as InAsSb based nBn devices. The described technique allows for simultaneous control of alloy composition and net strain, which are both key parameters for the photodetector operation.

  3. A novel member of the SAF (scaffold attachment factor)-box protein family inhibits gene expression and induces apoptosis

    PubMed Central

    Chan, Ching Wan; Lee, Youn-Bok; Uney, James; Flynn, Andrea; Tobias, Jonathan H.; Norman, Michael

    2007-01-01

    The SLTM [SAF (scaffold attachment factor)-like transcription modulator] protein contains a SAF-box DNA-binding motif and an RNA-binding domain, and shares an overall identity of 34% with SAFB1 {scaffold attachment factor-B1; also known as SAF-B (scaffold attachment factor B), HET [heat-shock protein 27 ERE (oestrogen response element) and TATA-box-binding protein] or HAP (heterogeneous nuclear ribonucleoprotein A1-interacting protein)}. Here, we show that SLTM is localized to the cell nucleus, but excluded from nucleoli, and to a large extent it co-localizes with SAFB1. In the nucleus, SLTM has a punctate distribution and it does not co-localize with SR (serine/arginine) proteins. Overexpression of SAFB1 has been shown to exert a number of inhibitory effects, including suppression of oestrogen signalling. Although SLTM also suppressed the ability of oestrogen to activate a reporter gene in MCF-7 breast-cancer cells, inhibition of a constitutively active β-galactosidase gene suggested that this was primarily the consequence of a generalized inhibitory effect on transcription. Measurement of RNA synthesis, which showed a particularly marked inhibition of [3H]uridine incorporation into mRNA, supported this conclusion. In addition, analysis of cell-cycle parameters, chromatin condensation and cytochrome c release showed that SLTM induced apoptosis in a range of cultured cell lines. Thus the inhibitory effects of SLTM on gene expression appear to result from generalized down-regulation of mRNA synthesis and initiation of apoptosis consequent upon overexpressing the protein. While indicating a crucial role for SLTM in cellular function, these results also emphasize the need for caution when interpreting phenotypic changes associated with manipulation of protein expression levels. PMID:17630952

  4. Externally tuned vibration absorber

    DOEpatents

    Vincent, Ronald J.

    1987-09-22

    A vibration absorber unit or units are mounted on the exterior housing of a hydraulic drive system of the type that is powered from a pressure wave generated, e.g., by a Stirling engine. The hydraulic drive system employs a piston which is hydraulically driven to oscillate in a direction perpendicular to the axis of the hydraulic drive system. The vibration absorbers each include a spring or other resilient member having one side affixed to the housing and another side to which an absorber mass is affixed. In a preferred embodiment, a pair of vibration absorbers is employed, each absorber being formed of a pair of leaf spring assemblies, between which the absorber mass is suspended.

  5. Shock absorber control system

    SciTech Connect

    Nakano, Y.; Ohira, M.; Ushida, M.; Miyagawa, T.; Shimodaira, T.

    1987-01-13

    A shock absorber control system is described for controlling a dampening force of a shock absorber of a vehicle comprising: setting means for setting a desired dampening force changeable within a predetermined range; drive means for driving the shock absorber to change the dampening force of the shock absorber linearly; control means for controlling the drive means in accordance with the desired dampening force when the setting of the desired dampening force has been changed; detecting means for detecting an actual dampening force of the shock absorber; and correcting means for correcting the dampening force of the shock absorber by controlling the drive means in accordance with a difference between the desired dampening force and the detected actual dampening force.

  6. CPCs with segmented absorbers

    SciTech Connect

    Keita, M.; Robertson, H.S. )

    1991-01-01

    One of the most promising means of improving the performance of solar thermal collectors is to reduce the energy lost by the hot absorber. One way to do this, not currently part of the technology, is to recognize that since the absorber is usually not irradiated uniformly, it is therefore possible to construct an absorber of thermally isolated segments, circulate the fluid in sequence from low to high irradiance segments, and reduce loss by improving effective concentration. This procedure works even for ideal concentrators, without violating Winston's theorem. Two equivalent CPC collectors with single and segmented absorber were constructed and compared under actual operating conditions. The results showed that the daily thermal efficiency of the collector with segmented absorber is higher (about 13%) than that of the collector with nonsegmented absorber.

  7. Methods for absorbing neutrons

    DOEpatents

    Guillen, Donna P [Idaho Falls, ID; Longhurst, Glen R [Idaho Falls, ID; Porter, Douglas L [Idaho Falls, ID; Parry, James R [Idaho Falls, ID

    2012-07-24

    A conduction cooled neutron absorber may include a metal matrix composite that comprises a metal having a thermal neutron cross-section of at least about 50 barns and a metal having a thermal conductivity of at least about 1 W/cmK. Apparatus for providing a neutron flux having a high fast-to-thermal neutron ratio may include a source of neutrons that produces fast neutrons and thermal neutrons. A neutron absorber positioned adjacent the neutron source absorbs at least some of the thermal neutrons so that a region adjacent the neutron absorber has a fast-to-thermal neutron ratio of at least about 15. A coolant in thermal contact with the neutron absorber removes heat from the neutron absorber.

  8. CDRD and PNPR satellite passive microwave precipitation retrieval algorithms: EuroTRMM/EURAINSAT origins and H-SAF operations

    NASA Astrophysics Data System (ADS)

    Mugnai, A.; Smith, E. A.; Tripoli, G. J.; Bizzarri, B.; Casella, D.; Dietrich, S.; Di Paola, F.; Panegrossi, G.; Sanò, P.

    2013-04-01

    Satellite Application Facility on Support to Operational Hydrology and Water Management (H-SAF) is a EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites) program, designed to deliver satellite products of hydrological interest (precipitation, soil moisture and snow parameters) over the European and Mediterranean region to research and operations users worldwide. Six satellite precipitation algorithms and concomitant precipitation products are the responsibility of various agencies in Italy. Two of these algorithms have been designed for maximum accuracy by restricting their inputs to measurements from conical and cross-track scanning passive microwave (PMW) radiometers mounted on various low Earth orbiting satellites. They have been developed at the Italian National Research Council/Institute of Atmospheric Sciences and Climate in Rome (CNR/ISAC-Rome), and are providing operational retrievals of surface rain rate and its phase properties. Each of these algorithms is physically based, however, the first of these, referred to as the Cloud Dynamics and Radiation Database (CDRD) algorithm, uses a Bayesian-based solution solver, while the second, referred to as the PMW Neural-net Precipitation Retrieval (PNPR) algorithm, uses a neural network-based solution solver. Herein we first provide an overview of the two initial EU research and applications programs that motivated their initial development, EuroTRMM and EURAINSAT (European Satellite Rainfall Analysis and Monitoring at the Geostationary Scale), and the current H-SAF program that provides the framework for their operational use and continued development. We stress the relevance of the CDRD and PNPR algorithms and their precipitation products in helping secure the goals of H-SAF's scientific and operations agenda, the former helpful as a secondary calibration reference to other algorithms in H-SAF's complete mix of algorithms. Descriptions of the algorithms' designs are provided

  9. A novel lab-on-chip platform with integrated solid phase PCR and Supercritical Angle Fluorescence (SAF) microlens array for highly sensitive and multiplexed pathogen detection.

    PubMed

    Hung, Tran Quang; Chin, Wai Hoe; Sun, Yi; Wolff, Anders; Bang, Dang Duong

    2017-04-15

    Solid-phase PCR (SP-PCR) has become increasingly popular for molecular diagnosis and there have been a few attempts to incorporate SP-PCR into lab-on-a-chip (LOC) devices. However, their applicability for on-line diagnosis is hindered by the lack of sensitive and portable on-chip optical detection technology. In this paper, we addressed this challenge by combining the SP-PCR with super critical angle fluorescence (SAF) microlens array embedded in a microchip. We fabricated miniaturized SAF microlens array as part of a microfluidic chamber in thermoplastic material and performed multiplexed SP-PCR directly on top of the SAF microlens array. Attribute to the high fluorescence collection efficiency of the SAF microlens array, the SP-PCR assay on the LOC platform demonstrated a high sensitivity of 1.6 copies/µL, comparable to off-chip detection using conventional laser scanner. The combination of SP-PCR and SAF microlens array allows for on-chip highly sensitive and multiplexed pathogen detection with low-cost and compact optical components. The LOC platform would be widely used as a high-throughput biosensor to analyze food, clinical and environmental samples.

  10. LSA SAF Meteosat FRP products - Part 1: Algorithms, product contents, and analysis

    NASA Astrophysics Data System (ADS)

    Wooster, M. J.; Roberts, G.; Freeborn, P. H.; Xu, W.; Govaerts, Y.; Beeby, R.; He, J.; Lattanzio, A.; Fisher, D.; Mullen, R.

    2015-11-01

    Characterizing changes in landscape fire activity at better than hourly temporal resolution is achievable using thermal observations of actively burning fires made from geostationary Earth Observation (EO) satellites. Over the last decade or more, a series of research and/or operational "active fire" products have been developed from geostationary EO data, often with the aim of supporting biomass burning fuel consumption and trace gas and aerosol emission calculations. Such Fire Radiative Power (FRP) products are generated operationally from Meteosat by the Land Surface Analysis Satellite Applications Facility (LSA SAF) and are available freely every 15 min in both near-real-time and archived form. These products map the location of actively burning fires and characterize their rates of thermal radiative energy release (FRP), which is believed proportional to rates of biomass consumption and smoke emission. The FRP-PIXEL product contains the full spatio-temporal resolution FRP data set derivable from the SEVIRI (Spinning Enhanced Visible and Infrared Imager) imager onboard Meteosat at a 3 km spatial sampling distance (decreasing away from the west African sub-satellite point), whilst the FRP-GRID product is an hourly summary at 5° grid resolution that includes simple bias adjustments for meteorological cloud cover and regional underestimation of FRP caused primarily by underdetection of low FRP fires. Here we describe the enhanced geostationary Fire Thermal Anomaly (FTA) detection algorithm used to deliver these products and detail the methods used to generate the atmospherically corrected FRP and per-pixel uncertainty metrics. Using SEVIRI scene simulations and real SEVIRI data, including from a period of Meteosat-8 "special operations", we describe certain sensor and data pre-processing characteristics that influence SEVIRI's active fire detection and FRP measurement capability, and use these to specify parameters in the FTA algorithm and to make recommendations

  11. Validation of the H-SAF precipitation product H03 over Greece using rain gauge data

    NASA Astrophysics Data System (ADS)

    Feidas, H.; Porcu, F.; Puca, S.; Rinollo, A.; Lagouvardos, C.; Kotroni, V.

    2016-11-01

    This paper presents an extensive validation of the combined infrared/microwave H-SAF (EUMETSAT Satellite Application Facility on Support to Operational Hydrology and Water Management) precipitation product H03, for a 1-year period, using gauge observations from a relatively dense network of 233 stations over Greece. First, the quality of the interpolated data used to validate the precipitation product is assessed and a quality index is constructed based on parameters such as the density of the station network and the orography. Then, a validation analysis is conducted based on comparisons of satellite (H03) with interpolated rain gauge data to produce continuous and multi-categorical statistics at monthly and annual timescales by taking into account the different geophysical characteristics of the terrain (land, coast, sea, elevation). Finally, the impact of the quality of interpolated data on the validation statistics is examined in terms of different configurations of the interpolation model and the rain gauge network characteristics used in the interpolation. The possibility of using a quality index of the interpolated data as a filter in the validation procedure is also investigated. The continuous validation statistics show yearly root mean squared error (RMSE) and mean absolute error (MAE) corresponding to the 225 and 105 % of the mean rain rate, respectively. Mean error (ME) indicates a slight overall tendency for underestimation of the rain gauge rates, which takes large values for the high rain rates. In general, the H03 algorithm cannot retrieve very well the light (< 1 mm/h) and the convective type (>10 mm/h) precipitation. The poor correlation between satellite and gauge data points to algorithm problems in co-locating precipitation patterns. Seasonal comparison shows that retrieval errors are lower for cold months than in the summer months of the year. The multi-categorical statistics indicate that the H03 algorithm is able to discriminate efficiently

  12. Leaf absorbance and photosynthesis

    NASA Technical Reports Server (NTRS)

    Schurer, Kees

    1994-01-01

    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  13. Advanced neutron absorber materials

    DOEpatents

    Branagan, Daniel J.; Smolik, Galen R.

    2000-01-01

    A neutron absorbing material and method utilizing rare earth elements such as gadolinium, europium and samarium to form metallic glasses and/or noble base nano/microcrystalline materials, the neutron absorbing material having a combination of superior neutron capture cross sections coupled with enhanced resistance to corrosion, oxidation and leaching.

  14. Assimilating soil moisture data in a hydrological model: a case study in Belgium using H-SAF products

    NASA Astrophysics Data System (ADS)

    Baguis, Pierre; Roulin, Emmanuel

    2016-04-01

    Precipitation is the main driving force for hydrological processes. There are however other physical variables, like soil moisture, that play an essential role in the hydrological cycle. In the present study, we focus on the use of a surface soil moisture (SSM) product in hydrological modelling. This product is generated using MetOp scatterometer (ASCAT) data at 25 km of horizontal resolution in the framework of the H-SAF project (EUMETSAT Satellite Application Facility on Support to Operational Hydrology and Water Management). The Royal Meteorological Institute of Belgium (RMI) is an active partner of H-SAF, involved in the validation of precipitation, soil moisture and snow products. In this work, we include in our hydrological simulations a soil moisture product through a data assimilation procedure. Our approach is based on the Ensemble Kalman Filter technique where observation and model uncertainties are taken into account. We first develop an assimilation scheme for surface soil moisture into the hydrological model of the RMI. In our implementation, bounded variables like SSM are handled with the aid of specially designed probability distributions so that the bounds are never exceeded. Subsequently, the impact of SSM assimilation on the simulated streamflow is assessed by using different sources of precipitation forcing. The ultimate goal is to provide new tools of hydrological validation and to investigate the possibilities of enhancing the quality of the simulated streamflow.

  15. Copper induces Cu-ATPase ATP7A mRNA in a fish cell line, SAF1.

    PubMed

    Minghetti, Matteo; Leaver, Michael J; Taggart, John B; Casadei, Elisa; Auslander, Meirav; Tom, Moshe; George, Stephen G

    2011-08-01

    Copper transporting ATPase, ATP7A, is an ATP dependent copper pump present in all vertebrates, critical for the maintenance of intracellular and whole body copper homeostasis. Effects of copper treatment on ATP7A gene expression in fibroblast cells (SAF1) of the sea bream (Sparus aurata) were investigated by qRT-PCR and by a medium density microarray from a closely related species, striped sea bream (Lithognathus mormyrus). To discriminate between the effects of Cu and other metals, SAF1 cells were exposed to sub-toxic levels of Cu, Zn and Cd. Expression of Cu homeostasis genes copper transporter 1 (CTR1), Cu ATPase (ATP7A), Cu chaperone (ATOX1) and metallothionein (MT) together with the oxidative stress markers glutathione reductase (GR) and Cu/Zn superoxide dismutase (CuZn/SOD) were measured 0, 4 and 24 hours post-exposure by qRT-PCR. Microarray was conducted on samples from 4 hours post Cu exposure. Cu, Zn and Cd increased MT and GR mRNA levels, while only Cu increased ATP7A mRNA levels. Microarray results confirmed the effects of Cu on ATP7A and MT and in addition showed changes in the expression of genes involved in protein transport and secretion. Results suggest that ATP7A may be regulated at the transcriptional level directly by Cu and by a mechanism that is different from that exerteted by metals on MT genes.

  16. Measuring conditions and trends in ecosystem services at multiple scales: the Southern African Millennium Ecosystem Assessment (SAfMA) experience

    PubMed Central

    van Jaarsveld, A.S; Biggs, R; Scholes, R.J; Bohensky, E; Reyers, B; Lynam, T; Musvoto, C; Fabricius, C

    2005-01-01

    The Southern African Millennium Ecosystem Assessment (SAfMA) evaluated the relationships between ecosystem services and human well-being at multiple scales, ranging from local through to sub-continental. Trends in ecosystem services (fresh water, food, fuel-wood, cultural and biodiversity) over the period 1990–2000 were mixed across scales. Freshwater resources appear strained across the continent with large numbers of people not securing adequate supplies, especially of good quality water. This translates to high infant mortality patterns across the region. In some areas, the use of water resources for irrigated agriculture and urban–industrial expansion is taking place at considerable cost to the quality and quantity of freshwater available to ecosystems and for domestic use. Staple cereal production across the region has increased but was outstripped by population growth while protein malnutrition is on the rise. The much-anticipated wood-fuel crisis on the subcontinent has not materialized but some areas are experiencing shortages while numerous others remain vulnerable. Cultural benefits of biodiversity are considerable, though hard to quantify or track over time. Biodiversity resources remain at reasonable levels, but are declining faster than reflected in species extinction rates and appear highly sensitive to land-use decisions. The SAfMA sub-global assessment provided an opportunity to experiment with innovative ways to assess ecosystem services including the use of supply–demand surfaces, service sources and sink areas, priority areas for service provision, service ‘hotspots’ and trade-off assessments. PMID:15814355

  17. Multispectral metamaterial absorber.

    PubMed

    Grant, J; McCrindle, I J H; Li, C; Cumming, D R S

    2014-03-01

    We present the simulation, implementation, and measurement of a multispectral metamaterial absorber (MSMMA) and show that we can realize a simple absorber structure that operates in the mid-IR and terahertz (THz) bands. By embedding an IR metamaterial absorber layer into a standard THz metamaterial absorber stack, a narrowband resonance is induced at a wavelength of 4.3 μm. This resonance is in addition to the THz metamaterial absorption resonance at 109 μm (2.75 THz). We demonstrate the inherent scalability and versatility of our MSMMA by describing a second device whereby the MM-induced IR absorption peak frequency is tuned by varying the IR absorber geometry. Such a MSMMA could be coupled with a suitable sensor and formed into a focal plane array, enabling multispectral imaging.

  18. Mechanism of activation of PhoQ/PhoP two-component signal transduction by SafA, an auxiliary protein of PhoQ histidine kinase in Escherichia coli.

    PubMed

    Ishii, Eiji; Eguchi, Yoko; Utsumi, Ryutaro

    2013-01-01

    The PhoQ/PhoP two-component signal transduction system in Escherichia coli is activated by SafA, a small membrane protein that modifies the PhoQ histidine kinase. The SafA C-terminal domain (41-65 aa) interacts directly with the sensory domain of PhoQ at the periplasm. We used in vitro and in vivo strategies to elucidate the way SafA modifies the PhoQ/PhoP phosphorelay system. First, the enzymatic activities of membranes from cells overexpressing PhoQ and cells expressing both PhoQ and SafA were compared in vitro. Increased autophosphorylation of PhoQ was observed in the presence of SafA, but it did not increase the dephosphorylation of phospho-PhoP by PhoQ. In addition, SafA increased the phospho-PhoP level on the phosphotransfer assay. We confirmed that induction of SafA results in an accumulation of phospho-PhoP in vivo by the Phos-tag system. Our results suggest that the accumulation of phospho-PhoP is linked to activation of PhoQ autophosphorylation by SafA.

  19. Internal absorber solar collector

    DOEpatents

    Sletten, Carlyle J.; Herskovitz, Sheldon B.; Holt, F. S.; Sletten, E. J.

    1981-01-01

    Thin solar collecting panels are described made from arrays of small rod collectors consisting of a refracting dielectric rod lens with an absorber imbedded within it and a reflecting mirror coated on the back side of the dielectric rod. Non-tracking collector panels on vertical walls or roof tops receive approximately 90% of solar radiation within an acceptance zone 60.degree. in elevation angle by 120.degree. or more in the azimuth sectors with a collector concentration ratio of approximately 3.0. Miniaturized construction of the circular dielectric rods with internal absorbers reduces the weight per area of glass, plastic and metal used in the collector panels. No external parts or insulation are needed as heat losses are low due to partial vacuum or low conductivity gas surrounding heated portions of the collector. The miniature internal absorbers are generally made of solid copper with black selective surface and the collected solar heat is extracted at the collector ends by thermal conductivity along the absorber rods. Heat is removed from end fittings by use of liquid circulants. Several alternate constructions are provided for simplifying collector panel fabrication and for preventing the thermal expansion and contraction of the heated absorber or circulant tubes from damaging vacuum seals. In a modified version of the internal absorber collector, oil with temperature dependent viscosity is pumped through a segmented absorber which is now composed of closely spaced insulated metal tubes. In this way the circulant is automatically diverted through heated portions of the absorber giving higher collector concentration ratios than theoretically possible for an unsegmented absorber.

  20. Lipid-absorbing Polymers

    NASA Technical Reports Server (NTRS)

    Marsh, H. E., Jr.; Wallace, C. J.

    1973-01-01

    The removal of bile acids and cholesterol by polymeric absorption is discussed in terms of micelle-polymer interaction. The results obtained with a polymer composed of 75 parts PEO and 25 parts PB plus curing ingredients show an absorption of 305 to 309%, based on original polymer weight. Particle size effects on absorption rate are analyzed. It is concluded that crosslinked polyethylene oxide polymers will absorb water, crosslinked polybutadiene polymers will absorb lipids; neither polymer will absorb appreciable amounts of lipids from micellar solutions of lipids in water.

  1. Electromagnetic power absorber

    NASA Technical Reports Server (NTRS)

    Iwasaki, R. S. (Inventor)

    1979-01-01

    A structure is presented with a surface portion of dielectric material which passes electromagnetic radiation and with a portion below the surface which includes material that absorbs the radiation, the face of the structure being formed with numerous steep ridges. The steepness of the dielectric material results in a high proportion of the electromagnetic energy passing through the surface for absorption by the absorbing material under the surface. A backing of aluminum or other highly heat-conductive and reflective material lies under the face and has very steep protuberances supporting the absorbing and dielectric materials.

  2. OVI absorbers in SDSS spectra

    NASA Astrophysics Data System (ADS)

    Frank, Stephan

    with the ubiquitous Lya forest lines, and estimate the success rate of retrieving each individual candidate as a function of its redshift, the emission redshift of the quasar, the strength of the absorber and the measured S/N of the spectrum by modelling typical Ly forest spectra. These correction factors allow us to derive the 'incompleteness and S/N corrected' redshift number densities of O VI absorbers. We can place a secure lower limit for the contribution of O VI to the closure mass density at the redshifts probed here: O OV I (2.8 < z < 3.2) >= 1.9 × 10 - 8 h -1 . We show that the strong lines we probe account for over 65% of the mass in the O VI absorbers; the weak absorbers, while dominant in line number density, do not contribute significantly to the mass density. Making a conservative assumption about the ionisation fraction, [Special characters omitted.] , and adopting the Anders & Grevesse (1989) solar abundance values, we derive the mean metallicty of the gas probed in our search : z(2.8 < z < 3.2) >= 3.6 × 10 -4 h , in good agreement with other studies. These results demonstrate that large spectroscopic datasets such as SDSS can play an important role in QSO absorption line studies, in spite of the relatively low resolution. Lastly, we have performed a stacking analysis whereby we shift individual spectra back to the rest-frame of the absorber candidate, and derive a mean absorption spectrum for various subsamples. Besides further validating the reality of the absorbers themselves, i.e. ruling out spurious interlopers and other misclassifications, we can use these stacked spectra for a variety of purposes. First of all, we can judge the effects of additional cut criteria like a minimal strength for associated CIV absorption, and hence produce cleaner and better defined subsamples, increasing the strength of future proposals for high-resolution studies. Secondly, the stack itself contains valuable information about the gas probed in our search. We have

  3. "Smart" Electromechanical Shock Absorber

    NASA Technical Reports Server (NTRS)

    Stokes, Lebarian; Glenn, Dean C.; Carroll, Monty B.

    1989-01-01

    Shock-absorbing apparatus includes electromechanical actuator and digital feedback control circuitry rather than springs and hydraulic damping as in conventional shock absorbers. Device not subject to leakage and requires little or no maintenance. Attenuator parameters adjusted in response to sensory feedback and predictive algorithms to obtain desired damping characteristic. Device programmed to decelerate slowly approaching vehicle or other large object according to prescribed damping characteristic.

  4. Comparative analysis of SAF, Protaper Next and BT-Race in eliminating Enterococcus faecalis from long oval canals: An ex vivo study.

    PubMed

    Krokidis, Andreas; Bonfanti, Carlo; Cerutti, Antonio; Barabanti, Nicola; Zinelis, Spyros; Panopoulos, Panos

    2016-11-03

    Comparison of the ability of newly designed rotary files to eliminate viable Enterococcus faecalis populations from long oval root canals of extracted human teeth to that of the self-adjusting file (SAF). One hundred caries-free, single-rooted, long oval teeth were contaminated with E. faecalis. The teeth were randomly distributed into four groups (n = 25) as follows: G.1, manual; G.2, SAF; G.3, ProTaper Next; and G.4, BT-Race. Two microbial samples were obtained from each tooth with sterile paper points, (s1) before and (s2) after instrumentation. The relative reduction in colony-forming units (CFUs) from s1 to s2 measurements was calculated and compared among the groups using parametric Kruskal-Wallis one-way anova on ranks and Dunn's method (a = 0.05). The results indicated a descending order of the groups with regard to efficacy as follows: BT-Race, Next, SAF and manual. The statistical analysis showed that the relative percentage reduction (RR) of CFUs was lower in the manual group than in the other groups, while the SAF group showed a significantly lower RR than the BT-Race group (P < 0.05). The efficacy in reduction of the microbiological load of viable E. faecalis from long oval root canals was different between the tested endodontic systems.

  5. Satellite-based datasets for validation of regional climate models: CM-SAF product suite and new tools for processing

    NASA Astrophysics Data System (ADS)

    Kaspar, F.; Schulz, J.; Hollmann, R.; Schröder, M.; Müller, R.; Karlsson, K.-G.; Roebeling, R.; Riihelä, A.; de Paepe, B.; Stöckli, R.

    2009-04-01

    Increasing the confidence in model-based climate projections requires evaluation of climate simulations with high-quality observational datasets. Satellite data provide information on the climate system that are not available or difficult to measure from the Earth‘s surface like top of atmosphere radiation, cloud properties or humidity in the upper atmosphere. In particular over ocean and sparsely populated areas space-based observations are largely the only data source. Especially for evaluating the generality of climate models across varying locations, satellite-derived datasets have the strong advantage of consistent measurements and processing methodologies across regions. Existing satellite time series, especially from operational meteorological satellites, now reach a length that makes them useful for climate analysis. Following this idea, EUMETSAT's Satellite Application Facility on Climate Monitoring (CM-SAF) is dedicated to the high-quality long-term monitoring of the climate system's state and variability. CM-SAF supports the analysis and diagnosis of climate parameters in order to detect and understand changes in the climate system. One goal is to support the climate modelling communities by the provision of satellite-derived geophysical parameter data sets. CM-SAF provides data sets of several cloud parameters, surface albedo, radiation fluxes at top of the atmosphere and at the surface, atmospheric temperature and water vapour profiles as well as vertically integrated water vapour (total, layered integrated). They are derived from geostationary (SEVIRI and GERB instruments) and polar-orbiting (AVHRR, ATOVS and SSM/I instruments) meteorological satellites. Products from the SEVIRI instrument on-board the geostationary Meteosat Second Generation satellites cover the full visible Earth disk, that extends from South America to the Middle East, with Africa fully included and Europe in the North. Products derived from the AVHRR-sensor on-board the polar

  6. The CM SAF ATOVS data record: overview of methodology and evaluation of total column water and profiles of tropospheric humidity

    NASA Astrophysics Data System (ADS)

    Courcoux, N.; Schröder, M.

    2015-12-01

    Recently, the reprocessed Advanced Television Infrared Observation Satellite (TIROS)-N Operational Vertical Sounder (ATOVS) tropospheric water vapour and temperature data record was released by the EUMETSAT Satellite Application Facility on Climate Monitoring (CM~SAF). ATOVS observations from infrared and microwave sounders onboard the National Oceanic and Atmospheric Agency (NOAA)-15-19 satellites and EUMETSAT's Meteorological Operational (Metop-A) satellite have been consistently reprocessed to generate 13 years (1999-2011) of global water vapour and temperature daily and monthly means with a spatial resolution of 90 km × 90 km. The data set is referenced under the following digital object identifier (DOI): SAF_CM/WVT_ATOVS/V001">doi:10.5676/EUM_SAF_CM/WVT_ATOVS/V001. After preprocessing, a maximum likelihood solution scheme was applied to the observations to simultaneously infer temperature and water vapour profiles. In a post-processing step, an objective interpolation method (Kriging) was applied to allow for gap filling. The product suite includes total precipitable water vapour (TPW), layer-integrated precipitable water vapour (LPW) and layer mean temperature for five tropospheric layers between the surface and 200 hPa, as well as specific humidity and temperature at six tropospheric levels between 1000 and 200 hPa. To our knowledge, this is the first time that the ATOVS record (1998-now) has been consistently reprocessed (1999-2011) to retrieve water vapour. TPW and LPW products were compared to corresponding products from the Global Climate Observing System (GCOS) Upper-Air Network (GUAN) radiosonde observations and from the Atmospheric Infrared Sounder (AIRS) version 5 satellite data record. TPW shows a good agreement with the GUAN radiosonde data: average bias and root mean square error (RMSE) are -0.2 and 3.3 kg m-2, respectively. For LPW, the maximum absolute (relative) bias and RMSE values decrease (increase

  7. Oxalate: Effect on calcium absorbability

    SciTech Connect

    Heaney, R.P.; Weaver, C.M. )

    1989-10-01

    Absorption of calcium from intrinsically labeled Ca oxalate was measured in 18 normal women and compared with absorption of Ca from milk in these same subjects, both when the test substances were ingested in separate meals and when ingested together. Fractional Ca absorption from oxalate averaged 0.100 +/- 0.043 when ingested alone and 0.140 +/- 0.063 when ingested together with milk. Absorption was, as expected, substantially lower than absorption from milk (0.358 +/- 0.113). Nevertheless Ca oxalate absorbability in these women was higher than we had previously found for spinach Ca. When milk and Ca oxalate were ingested together, there was no interference of oxalate in milk Ca absorption and no evidence of tracer exchange between the two labeled Ca species.

  8. Unidirectional perfect absorber

    PubMed Central

    Jin, L.; Wang, P.; Song, Z.

    2016-01-01

    This study proposes a unidirectional perfect absorber (UPA), which we realized with a two-arm Aharonov-Bohm interferometer, that consists of a dissipative resonator side-coupled to a uniform resonator array. The UPA has reflection-less full absorption on one direction, and reflectionless full transmission on the other, with an appropriate magnetic flux and coupling, detuning, and loss of the side-coupled resonator. The magnetic flux controls the transmission, the left transmission is larger for magnetic flux less than one-half flux quantum; and the right transmission is larger for magnetic flux between one-half and one flux quantum. Besides, a perfect absorber (PA) can be realized based on the UPA, in which light waves from both sides, with arbitrary superposition of the ampli- tude and phase, are perfectly absorbed. The UPA is expected to be useful in the design of novel optical devices. PMID:27615125

  9. Shock absorber servicing tool

    NASA Technical Reports Server (NTRS)

    Koepler, Jack L. (Inventor); Hill, Robert L. (Inventor)

    1981-01-01

    A tool to assist in the servicing of a shock absorber wherein the shock absorber is constructed of a pair of aligned gas and liquid filled chambers. Each of the chambers is separated by a movable separator member. Maximum efficiency of the shock absorber is achieved in the locating of a precise volume of gas within the gas chamber and a precise volume of liquid within the liquid chamber. The servicing tool of this invention employs a rod which is to connect with the separator and by observation of the position of the rod with respect to the gauge body, the location of the separator is ascertained even though it is not directly observable.

  10. Unidirectional perfect absorber

    NASA Astrophysics Data System (ADS)

    Jin, L.; Wang, P.; Song, Z.

    2016-09-01

    This study proposes a unidirectional perfect absorber (UPA), which we realized with a two-arm Aharonov-Bohm interferometer, that consists of a dissipative resonator side-coupled to a uniform resonator array. The UPA has reflection-less full absorption on one direction, and reflectionless full transmission on the other, with an appropriate magnetic flux and coupling, detuning, and loss of the side-coupled resonator. The magnetic flux controls the transmission, the left transmission is larger for magnetic flux less than one-half flux quantum; and the right transmission is larger for magnetic flux between one-half and one flux quantum. Besides, a perfect absorber (PA) can be realized based on the UPA, in which light waves from both sides, with arbitrary superposition of the ampli- tude and phase, are perfectly absorbed. The UPA is expected to be useful in the design of novel optical devices.

  11. Shock Absorbing System

    NASA Astrophysics Data System (ADS)

    1982-01-01

    A lightweight, inexpensive shock-absorbing system, developed by Langley Research Center 20 years ago, is now in service as safety device for an automated railway at Duke University Medical Center. The transportation system travels at about 25 miles per hour, carrying patients, visitors, staff and cargo. At the end of each guideway of the system are "frangible," (breakable) tube "buffers." If a slowing car fails to make a complete stop at the terminal, it would bump and shatter the tubes, absorbing energy that might otherwise jolt the passengers or damage the vehicle.

  12. Solar concentrator/absorber

    NASA Technical Reports Server (NTRS)

    Von Tiesenhausen, G. F.

    1976-01-01

    Collector/energy converter, consisting of dual-slope optical concentrator and counterflow thermal energy absorber, is attached to multiaxis support structure. Efficient over wide range of illumination levels, device may be used to generate high temperature steam, serve as solar powered dryer, or power absorption cycle cooler.

  13. Neutron Absorbing Alloys

    SciTech Connect

    Mizia, Ronald E.; Shaber, Eric L.; DuPont, John N.; Robino, Charles V.; Williams, David B.

    2004-05-04

    The present invention is drawn to new classes of advanced neutron absorbing structural materials for use in spent nuclear fuel applications requiring structural strength, weldability, and long term corrosion resistance. Particularly, an austenitic stainless steel alloy containing gadolinium and less than 5% of a ferrite content is disclosed. Additionally, a nickel-based alloy containing gadolinium and greater than 50% nickel is also disclosed.

  14. Shock Absorbing Helmets

    NASA Technical Reports Server (NTRS)

    1978-01-01

    This paper presents a description of helmets used by football players that offer three times the shock-absorbing capacity of earlier types. An interior padding for the helmets, composed of Temper Foam, first used by NASA's Ames Research Center in the design of aircraft seats is described.

  15. Fractional randomness

    NASA Astrophysics Data System (ADS)

    Tapiero, Charles S.; Vallois, Pierre

    2016-11-01

    The premise of this paper is that a fractional probability distribution is based on fractional operators and the fractional (Hurst) index used that alters the classical setting of random variables. For example, a random variable defined by its density function might not have a fractional density function defined in its conventional sense. Practically, it implies that a distribution's granularity defined by a fractional kernel may have properties that differ due to the fractional index used and the fractional calculus applied to define it. The purpose of this paper is to consider an application of fractional calculus to define the fractional density function of a random variable. In addition, we provide and prove a number of results, defining the functional forms of these distributions as well as their existence. In particular, we define fractional probability distributions for increasing and decreasing functions that are right continuous. Examples are used to motivate the usefulness of a statistical approach to fractional calculus and its application to economic and financial problems. In conclusion, this paper is a preliminary attempt to construct statistical fractional models. Due to the breadth and the extent of such problems, this paper may be considered as an initial attempt to do so.

  16. Metasurface Broadband Solar Absorber

    PubMed Central

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Sykora, Milan; Weisse-Bernstein, Nina R.; Luk, Ting S.; Taylor, Antoinette J.; Dalvit, Diego A. R.; Chen, Hou-Tong

    2016-01-01

    We demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure. PMID:26828999

  17. Metasurface Broadband Solar Absorber

    DOE PAGES

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Sykora, Milan; ...

    2016-02-01

    Here, we demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Moreover, our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributionsmore » to elucidate how the absorption occurs within the metasurface structure.« less

  18. Metasurface Broadband Solar Absorber

    SciTech Connect

    Azad, Abul K.; Kort-Kamp, Wilton J. M.; Sykora, Milan; Weisse-Bernstein, Nina R.; Luk, Ting S.; Taylor, Antoinette J.; Dalvit, Diego A. R.; Chen, Hou-Tong

    2016-02-01

    Here, we demonstrate a broadband, polarization independent, wide-angle absorber based on a metallic metasurface architecture, which accomplishes greater than 90% absorptance in the visible and near-infrared range of the solar spectrum, and exhibits low absorptivity (emissivity) at mid- and far-infrared wavelengths. The complex unit cell of the metasurface solar absorber consists of eight pairs of gold nano-resonators that are separated from a gold ground plane by a thin silicon dioxide spacer. Moreover, our experimental measurements reveal high-performance absorption over a wide range of incidence angles for both s- and p-polarizations. We also investigate numerically the frequency-dependent field and current distributions to elucidate how the absorption occurs within the metasurface structure.

  19. Ionized Absorbers in AGN

    NASA Technical Reports Server (NTRS)

    Mathur, S.

    1999-01-01

    As a part of this program, we observed three AGN:PKS2251 + 113, PG0043 = 039 and PLH909. Two objects show signatures of absorbtion in their UV spectra. Based on our earlier modeling of X-ray warm absorbents, we expected to observe X-ray observation in these objects. The third, PLH909, is known to have soft excess in EINSTEIN data. Attachment: "Exploratory ASCA observation of broad absorption line quasi-stellar objects".

  20. Apollo couch energy absorbers

    NASA Technical Reports Server (NTRS)

    Wesselski, C. J.; Drexel, R. E.

    1972-01-01

    Load attenuators for the Apollo spacecraft crew couch and its potential applications are described. Energy absorption is achieved through friction and cyclic deformation of material. In one concept, energy absorption is accomplished by rolling a compressed ring of metal between two surfaces. In another concept, energy is absorbed by forcing a plastically deformed washer along a rod. Among the design problems that had to be solved were material selection, fatigue life, ring slippage, lubrication, and friction loading.

  1. MODIS Measures Fraction of Sunlight Absorbed by Plants

    NASA Technical Reports Server (NTRS)

    2002-01-01

    At the height of the solar cycle, the Sun is finally displaying some fireworks. This image from the Solar and Heliospheric Observatory (SOHO) shows a large solar flare from June 6, 2000 at 1424 Universal Time (10:24 AM Eastern Daylight Savings Time). Associated with the flare was a coronal mass ejection that sent a wave of fast moving charged particles straight towards Earth. (The image was acquired by the Extreme ultaviolet Imaging Telescope (EIT), one of 12 instruments aboard SOHO) Solar activity affects the Earth in several ways. The particles generated by flares can disrupt satellite communications and interfere with power transmission on the Earth's surface. Earth's climate is tied to the total energy emitted by the sun, cooling when the sun radiates less energy and warming when solar output increases. Solar radiation also produces ozone in the stratosphere, so total ozone levels tend to increase during the solar maximum. For more information about these solar flares and the SOHO mission, see NASA Science News or the SOHO home page. For more about the links between the sun and climate change, see Sunspots and the Solar Max. Image courtesy SOHO Extreme ultaviolet Imaging Telescope, ESA/NASA

  2. Sensitization phenomena on aged SAF 2205 duplex stainless steel and their control using the electrochemical potentiokinetic reactivation test

    SciTech Connect

    Angelini, E.; Benedetti, B. de; Maizza, G.; Rosalbino, F. . Dept. of Materials Science and Chemical Engineering)

    1999-06-01

    Microstructural changes and resulting properties were studied for SAF 2205 (UNS S31803) austeno-ferritic stainless steel (SS) aged between 700 C and 900 C for up to 2 weeks and then water-quenched. Quantitative metallography coupled with x-ray diffraction techniques were adopted to follow ferrite ([alpha]) transformation with subsequent formation of secondary austenite ([gamma][sub 2]) and sigma ([sigma]) phase. The kinetic model of a transformation was interpreted in the form of an Avrami-type expression. The electrochemical potentiokinetic reactivation (EPR) test was used to evaluate the degree of sensitization of the aged specimens. Results were compared with results from the corrosion test in boiling nitric acid (HNO[sub 3]). Influences of the transformation of ferrite into austenite, sigma phase, and of other microstructural variations such as chromium nitride (Cr[sub 2]N) precipitation on stability of the passive film were shown. The susceptibility to intergranular corrosion phenomena was caused by chromium depletion caused by sigma phase precipitation, while chromium nitrides appeared less harmful. Results were expressed as an isocharge line diagram that allowed concise identification of sensitization and desensitization ranges.

  3. Nephrology and Doctors Honoris Causa at P. J. Safárik University in Kosice in the years 1993-2006 (Slovak Republic).

    PubMed

    Mydlík, Miroslav; Derzsiová, Katarína; Vajó, Julius

    2009-01-01

    The authors present a brief history of the activities of 7 important and well-known foreign nephrologists in Kosice and in the region of Eastern Slovakia who were awarded the honorary title Doctor Honoris Causa by P. J. Safárik University in Kosice. The above-mentioned professors presented their papers as guest professors to the students of the Medical Faculty of P. J. Safárik University and in meetings of medical societies and at many symposia and congresses with international participation in the region of Eastern Slovakia. All of the awarded nephrologists have visited the Faculty Hospital of L. Pasteur, the Fourth Internal Clinic and the Nephrological Clinic. During their stays, they stimulated the thinking of researchers in other metabolic studies within clinical nephrology and toxicology. In addition they contributed to the establishment in 1997 of the Nephrological Clinic of the Medical Faculty of P. J. Safárik University and the Faculty Hospital of L. Pasteur, the first one of its kind in the Slovak Republic.

  4. Absorber for terahertz radiation management

    SciTech Connect

    Biallas, George Herman; Apeldoorn, Cornelis; Williams, Gwyn P.; Benson, Stephen V.; Shinn, Michelle D.; Heckman, John D.

    2015-12-08

    A method and apparatus for minimizing the degradation of power in a free electron laser (FEL) generating terahertz (THz) radiation. The method includes inserting an absorber ring in the FEL beam path for absorbing any irregular THz radiation and thus minimizes the degradation of downstream optics and the resulting degradation of the FEL output power. The absorber ring includes an upstream side, a downstream side, and a plurality of wedges spaced radially around the absorber ring. The wedges form a scallop-like feature on the innermost edges of the absorber ring that acts as an apodizer, stopping diffractive focusing of the THz radiation that is not intercepted by the absorber. Spacing between the scallop-like features and the shape of the features approximates the Bartlett apodization function. The absorber ring provides a smooth intensity distribution, rather than one that is peaked on-center, thereby eliminating minor distortion downstream of the absorber.

  5. Corrosion resistant neutron absorbing coatings

    DOEpatents

    Choi, Jor-Shan [El Cerrito, CA; Farmer, Joseph C [Tracy, CA; Lee, Chuck K [Hayward, CA; Walker, Jeffrey [Gaithersburg, MD; Russell, Paige [Las Vegas, NV; Kirkwood, Jon [Saint Leonard, MD; Yang, Nancy [Lafayette, CA; Champagne, Victor [Oxford, PA

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  6. Corrosion resistant neutron absorbing coatings

    DOEpatents

    Choi, Jor-Shan; Farmer, Joseph C; Lee, Chuck K; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

    2013-11-12

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  7. Solar radiation absorbing material

    DOEpatents

    Googin, John M.; Schmitt, Charles R.; Schreyer, James M.; Whitehead, Harlan D.

    1977-01-01

    Solar energy absorbing means in solar collectors are provided by a solar selective carbon surface. A solar selective carbon surface is a microporous carbon surface having pores within the range of 0.2 to 2 micrometers. Such a surface is provided in a microporous carbon article by controlling the pore size. A thermally conductive substrate is provided with a solar selective surface by adhering an array of carbon particles in a suitable binder to the substrate, a majority of said particles having diameters within the range of about 0.2-10 microns.

  8. Liquid Cryogen Absorber for MICE

    SciTech Connect

    Baynham, D.E.; Bish, P.; Bradshaw, T.W.; Cummings, M.A.; Green,M.A.; Ishimoto, S.; Ivaniouchenkov, I.; Lau, W.; Yang, S.Q.; Zisman, M.S.

    2005-08-20

    The Muon Ionization Cooling Experiment (MICE) will test ionization cooling of muons. In order to have effective ionization cooling, one must use an absorber that is made from a low-z material. The most effective low z materials for ionization cooling are hydrogen, helium, lithium hydride, lithium and beryllium, in that order. In order to measure the effect of material on cooling, several absorber materials must be used. This report describes a liquid-hydrogen absorber that is within a pair of superconducting focusing solenoids. The absorber must also be suitable for use with liquid helium. The following absorber components are discussed in this report; the absorber body, its heat exchanger, the hydrogen system, and the hydrogen safety. Absorber cooling and the thin windows are not discussed here.

  9. Ferroelectrics based absorbing layers

    NASA Astrophysics Data System (ADS)

    Hao, Jianping; Sadaune, Véronique; Burgnies, Ludovic; Lippens, Didier

    2014-07-01

    We show that ferroelectrics-based periodic structure made of BaSrTiO3 (BST) cubes, arrayed onto a metal plate with a thin dielectric spacer film exhibit a dramatic enhancement of absorbance with value close to unity. The enhancement is found around the Mie magnetic resonance of the Ferroelectrics cubes with the backside metal layer stopping any transmitted waves. It also involves quasi-perfect impedance matching resulting in reflection suppression via simultaneous magnetic and electrical activities. In addition, it was shown numerically the existence of a periodicity optimum, which is explained from surface waves analysis along with trade-off between the resonance damping and the intrinsic loss of ferroelectrics cubes. An experimental verification in a hollow waveguide configuration with a good comparison with full-wave numerical modelling is at last reported by measuring the scattering parameters of single and dual BST cubes schemes pointing out coupling effects for densely packed structures.

  10. Dual broadband metamaterial absorber.

    PubMed

    Kim, Young Ju; Yoo, Young Joon; Kim, Ki Won; Rhee, Joo Yull; Kim, Yong Hwan; Lee, YoungPak

    2015-02-23

    We propose polarization-independent and dual-broadband metamaterial absorbers at microwave frequencies. This is a periodic meta-atom array consisting of metal-dielectric-multilayer truncated cones. We demonstrate not only one broadband absorption from the fundamental magnetic resonances but additional broadband absorption in high-frequency range using the third-harmonic resonance, by both simulation and experiment. In simulation, the absorption was over 90% in 3.93-6.05 GHz, and 11.64-14.55 GHz. The corresponding experimental absorption bands over 90% were 3.88-6.08 GHz, 9.95-10.46 GHz and 11.86-13.84 GHz, respectively. The origin of absorption bands was elucidated. Furthermore, it is independent of polarization angle owing to the multilayered circular structures. The design is scalable to smaller size for the infrared and the visible ranges.

  11. THz-metamaterial absorbers

    NASA Astrophysics Data System (ADS)

    Tuong Pham, Van; Park, J. W.; Vu, Dinh Lam; Zheng, H. Y.; Rhee, J. Y.; Kim, K. W.; Lee, Y. P.

    2013-03-01

    An ultrabroad-band metamaterial absorber was investigated in mid-IR regime based on a similar model in previous work. The high absorption of metamaterial was obtained in a band of 8-11.7 THz with energy loss distributed in SiO2, which is appropriate potentially for solar-cell applications. A perfect absorption peak was provided by using a sandwich structure with periodical anti-dot pattern in the IR region, getting closed to visible-band metamaterials. The dimensional parameters were examined for the corresponding fabrication. Invited talk at the 6th International Workshop on Advanced Materials Science and Nanotechnology, 30 October-2 November, 2012, Ha Long, Vietnam.

  12. Understanding Multiplication of Fractions.

    ERIC Educational Resources Information Center

    Sweetland, Robert D.

    1984-01-01

    Discussed the use of Cuisenaire rods in teaching the multiplication of fractions. Considers whole number times proper fraction, proper fraction multiplied by proper fraction, mixed number times proper fraction, and mixed fraction multiplied by mixed fractions. (JN)

  13. Electrochemically regenerable carbon dioxide absorber

    NASA Technical Reports Server (NTRS)

    Woods, R. R.; Marshall, R. D.; Schubert, F. H.; Heppner, D. B.

    1979-01-01

    Preliminary designs were generated for two electrochemically regenerable carbon dioxide absorber concepts. Initially, an electrochemically regenerable absorption bed concept was designed. This concept incorporated the required electrochemical regeneration components in the absorber design, permitting the absorbent to be regenerated within the absorption bed. This hardware was identified as the electrochemical absorber hardware. The second hardware concept separated the functional components of the regeneration and absorption process. This design approach minimized the extravehicular activity component volume by eliminating regeneration hardware components within the absorber. The electrochemical absorber hardware was extensively characterized for major operating parameters such as inlet carbon dioxide partial pressure, process air flow rate, operational pressure, inlet relative humidity, regeneration current density and absorption/regeneration cycle endurance testing.

  14. Broadband patterned magnetic microwave absorber

    SciTech Connect

    Li, Wei; Wu, Tianlong; Wang, Wei; Guan, Jianguo; Zhai, Pengcheng

    2014-07-28

    It is a tough task to greatly improve the working bandwidth for the traditional flat microwave absorbers because of the restriction of available material parameters. In this work, a simple patterning method is proposed to drastically broaden the absorption bandwidth of a conventional magnetic absorber. As a demonstration, an ultra-broadband microwave absorber with more than 90% absorption in the frequency range of 4–40 GHz is designed and experimentally realized, which has a thin thickness of 3.7 mm and a light weight equivalent to a 2-mm-thick flat absorber. In such a patterned absorber, the broadband strong absorption is mainly originated from the simultaneous incorporation of multiple λ/4 resonances and edge diffraction effects. This work provides a facile route to greatly extend the microwave absorption bandwidth for the currently available absorbing materials.

  15. Liquid Hydrogen Absorber for MICE

    SciTech Connect

    Ishimoto, S.; Suzuki, S.; Yoshida, M.; Green, Michael A.; Kuno, Y.; Lau, Wing

    2010-05-30

    Liquid hydrogen absorbers for the Muon Ionization Cooling Experiment (MICE) have been developed, and the first absorber has been tested at KEK. In the preliminary test at KEK we have successfully filled the absorber with {approx}2 liters of liquid hydrogen. The measured hydrogen condensation speed was 2.5 liters/day at 1.0 bar. No hydrogen leakage to vacuum was found between 300 K and 20 K. The MICE experiment includes three AFC (absorber focusing coil) modules, each containing a 21 liter liquid hydrogen absorber made of aluminum. The AFC module has safety windows to separate its vacuum from that of neighboring modules. Liquid hydrogen is supplied from a cryocooler with cooling power 1.5 W at 4.2 K. The first absorber will be assembled in the AFC module and installed in MICE at RAL.

  16. Improved retrieval of direct and diffuse downwelling surface shortwave flux in cloudless atmosphere using dynamic estimates of aerosol content and type: application to the LSA-SAF project

    NASA Astrophysics Data System (ADS)

    Ceamanos, X.; Carrer, D.; Roujean, J.-L.

    2014-03-01

    Downwelling surface shortwave flux (DSSF) is a key parameter to address many climate, meteorological, and solar energy issues. Under clear sky conditions, DSSF is particularly sensitive to the variability both in time and space of the aerosol load and chemical composition. Hitherto, this dependence has not been properly addressed by the Satellite Application Facility on Land Surface Analysis (LSA-SAF), which operationally disseminates instantaneous DSSF products over the continents since 2005 considering unchanging aerosol conditions. In the present study, an efficient method is proposed for DSSF retrieval that will overcome the limitations of the current LSA-SAF product. This method referred to as SIRAMix (Surface Incident Radiation estimation using Aerosol Mixtures) is based on an accurate physical parameterization that is coupled with a radiative transfer-based look up table of aerosol properties. SIRAMix considers an aerosol layer constituted of several major aerosol species that are conveniently mixed to match real aerosol conditions. This feature of SIRAMix allows it to provide not only accurate estimates of global DSSF but also the direct and diffuse DSSF components, which are crucial radiative terms in many climatological applications. The implementation of SIRAMix is tested in the present article using atmospheric inputs from the European Center for Medium-Range Weather Forecasts (ECMWF). DSSF estimates provided by SIRAMix are compared against instantaneous DSSF measurements taken at several ground stations belonging to several radiation measurement networks. Results show an average root mean square error (RMSE) of 23.6 W m-2, 59.1 W m-2, and 44.9 W m-2 for global, direct, and diffuse DSSF, respectively. These scores decrease the average RMSE obtained for the current LSA-SAF product by 18.6%, which only provides global DSSF for the time being, and, to a lesser extent, for the state of the art in matter of DSSF retrieval (RMSE decrease of 10.9%, 6.5%, and

  17. Mystery Fractions

    ERIC Educational Resources Information Center

    Bhattacharyya, Sonalee; Namakshi, Nama; Zunker, Christina; Warshauer, Hiroko K.; Warshauer, Max

    2016-01-01

    Making math more engaging for students is a challenge that every teacher faces on a daily basis. These authors write that they are constantly searching for rich problem-solving tasks that cover the necessary content, develop critical-thinking skills, and engage student interest. The Mystery Fraction activity provided here focuses on a key number…

  18. Pitch Fractionation.

    DTIC Science & Technology

    1981-12-15

    13 3. Solvent Fractionation Experiments .................................... 15 4. Fourier Transform Infrared Spectra for A240 Petrolem Pitch AG 12...34 and Mesophase Pitch AG 164B ............................... 21 5. Fourier Transform Infrared Spectra ................................... 23 6...compared by Fourier transform infrared (FTIR) analysis using a Digilab Model FTS 14 spectrophotometer (Rockwell International, Anaheim, California

  19. SAF-RON GOLD

    EPA Pesticide Factsheets

    Technical product bulletin: this dispersant used in oil spill cleanups can be applied by aerial or boat sprayer. A recommended dispersant to water ratio of 1:40 can be used for most spills. Ratios are dependent upon type of oil and weather conditions.

  20. Energy absorber for the CETA

    NASA Technical Reports Server (NTRS)

    Wesselski, Clarence J.

    1994-01-01

    The energy absorber that was developed for the CETA (Crew Equipment and Translation Aid) on Space Station Freedom is a metal on metal frictional type and has a load regulating feature that prevents excessive stroking loads from occurring while in operation. This paper highlights some of the design and operating aspects and the testing of this energy absorber.

  1. Improvement Of The Helmholtz Absorber

    NASA Technical Reports Server (NTRS)

    Morrow, Duane L.

    1992-01-01

    Helmholtz-resonator system improved to enable it to absorb sound at more than one frequency without appreciable loss of effectiveness at primary frequency. Addition of annular cavities enables absorption of sound at harmonic frequencies in addition to primary frequency. Improved absorber designed for use on structures of high transmission loss. Applied to such machines as fixed-speed engines and fans.

  2. Metal-shearing energy absorber

    NASA Technical Reports Server (NTRS)

    Fay, R. J.; Wittrock, E. P.

    1971-01-01

    Device, consisting of tongue of thin aluminum alloy strip, pull tab, slotted steel plate which serves as cutter, and steel buckle, absorbs mechanical energy when its ends are subjected to tensile loading. Device is applicable as auxiliary shock absorbing anchor for automobile and airplane safety belts.

  3. Fraction Reduction through Continued Fractions

    ERIC Educational Resources Information Center

    Carley, Holly

    2011-01-01

    This article presents a method of reducing fractions without factoring. The ideas presented may be useful as a project for motivated students in an undergraduate number theory course. The discussion is related to the Euclidean Algorithm and its variations may lead to projects or early examples involving efficiency of an algorithm.

  4. Isotope fractionation

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    A rash of new controversy has emerged around the subject of mass-independent isotope fractionation effects, particularly in the case of the oxygen isotopes. To be sure, the controversy has been around for awhile, but it has been given new impetus by the results of a recent study by Mark H. Thiemens and John E. Heidenreich III of the University of California, San Diego (Science, March 4, 1983).Gustav Arrhenius has been trying to convince the planetary science community that chemical effects in isotope fractionation processes could explain observations in meteorites that appear to be outside of the traditionally understood mass-dependent fractionations (G. Arrhenius, J . L. McCrumb, and N. F. Friedman, Astrophys. Space Sci, 65, 297, 1974). Robert Clayton had made the basic observations of oxygen in carbonaceous chondrites that the slope of the δ17 versus δ18 line was 1 instead of the slope of ½ characteristic of terrestrial rocks and lunar samples (Ann. Rev. Nucl. Part. Sci., 28, 501, 1978). The mass-independent effects were ascribed to the apparent contribution of an ancient presolar system component of O16.

  5. Highly efficient and robust operation of Kerr-lens mode-locked Cr:LiSAF lasers using gain-matched output couplers.

    PubMed

    Canbaz, Ferda; Beyatli, Ersen; Chen, Li-Jin; Sennaroglu, Alphan; Kärtner, Franz X; Demirbas, Umit

    2014-01-15

    We present efficient and robust Kerr-lens mode locking (KLM) of a diode-pumped Cr:LiSAF laser using a gain-matched output coupler (GMOC). An inexpensive, battery-powered 660 nm single-spatial-mode diode was used as the pump source. GMOC enhances the effective self-amplitude modulation depth by reducing the gain-filtering effect in broadband KLM operation to provide significant improvement in efficiency and robustness. Pulsing can be initiated without careful cavity alignment and is sustained for hours. 13 fs pulses with an average power of 25 mW have been generated using only 120 mW of pump power. The corresponding pulse energy and peak power is 200 pJ and 15 kW for the 126 MHz repetition rate cavity. Optical-to-optical conversion efficiency of the system is 21%, which represents an order of magnitude improvement in reported efficiencies for such diode-pumped ultrashort-pulse KLM Cr:LiSAF lasers. The obtainable pulse width is currently limited by the dispersion bandwidth of the available optics and can be potentially reduced to below 7 fs.

  6. Absorbent product to absorb fluids. [for collection of human wastes

    NASA Technical Reports Server (NTRS)

    Dawn, F. S.; Correale, J. V. (Inventor)

    1982-01-01

    A multi-layer absorbent product for use in contact with the skin to absorb fluids is discussed. The product utilizes a water pervious facing layer for contacting the skin, overlayed by a first fibrous wicking layer, the wicking layer preferably being of the one-way variety in which fluid or liquid is moved away from the facing layer. The product further includes a first container section defined by inner and outer layer of a water pervious wicking material between which is disposed a first absorbent mass. A second container section defined by inner and outer layers between which is disposed a second absorbent mass and a liquid impermeable/gas permeable layer. Spacesuit applications are discussed.

  7. An introduction to absorbent dressings.

    PubMed

    Jones, Menna Lloyd

    2014-12-01

    Exudate bathes the wound bed with a serous fluid that contains essential components that promote wound healing. However, excess exudate is often seen as a challenge for clinicians. Absorbent dressings are often used to aid in the management of exudate, with the aim of providing a moist but unmacerated environment. With so many different types of absorbent dressings available today-alongside making a holistic assessment-it is essential that clinicians also have the knowledge and skill to select the most appropriate absorbent dressing for a given patient.

  8. Self-Regulating Shock Absorber

    NASA Technical Reports Server (NTRS)

    Wesselski, Clarence J.

    1995-01-01

    Mechanical shock absorber keeps frictional damping force within tolerable limit. Its damping force does not increase with coefficient of friction between energy-absorbing components; rather, frictional damping force varies only slightly. Relatively insensitive to manufacturing variations and environmental conditions altering friction. Does not exhibit high breakaway friction and consequent sharp increase followed by sharp decrease in damping force at beginning of stroking. Damping force in absorber does not vary appreciably with speed of stroking. In addition, not vulnerable to leakage of hydraulic fluid.

  9. LSA SAF Meteosat FRP Products: Part 2 - Evaluation and demonstration of use in the Copernicus Atmosphere Monitoring Service (CAMS)

    NASA Astrophysics Data System (ADS)

    Roberts, G.; Wooster, M. J.; Xu, W.; Freeborn, P. H.; Morcrette, J.-J.; Jones, L.; Benedetti, A.; Kaiser, J.

    2015-06-01

    Characterising the dynamics of landscape scale wildfires at very high temporal resolutions is best achieved using observations from Earth Observation (EO) sensors mounted onboard geostationary satellites. As a result, a number of operational active fire products have been developed from the data of such sensors. An example of which are the Fire Radiative Power (FRP) products, the FRP-PIXEL and FRP-GRID products, generated by the Land Surface Analysis Satellite Applications Facility (LSA SAF) from imagery collected by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on-board the Meteosat Second Generation (MSG) series of geostationary EO satellites. The processing chain developed to deliver these FRP products detects SEVIRI pixels containing actively burning fires and characterises their FRP output across four geographic regions covering Europe, part of South America and northern and southern Africa. The FRP-PIXEL product contains the highest spatial and temporal resolution FRP dataset, whilst the FRP-GRID product contains a spatio-temporal summary that includes bias adjustments for cloud cover and the non-detection of low FRP fire pixels. Here we evaluate these two products against active fire data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS), and compare the results to those for three alternative active fire products derived from SEVIRI imagery. The FRP-PIXEL product is shown to detect a substantially greater number of active fire pixels than do alternative SEVIRI-based products, and comparison to MODIS on a per-fire basis indicates a strong agreement and low bias in terms of FRP values. However, low FRP fire pixels remain undetected by SEVIRI, with errors of active fire pixel detection commission and omission compared to MODIS ranging between 9-13 and 65-77% respectively in Africa. Higher errors of omission result in greater underestimation of regional FRP totals relative to those derived from simultaneously collected MODIS

  10. LSA SAF Meteosat FRP products - Part 2: Evaluation and demonstration for use in the Copernicus Atmosphere Monitoring Service (CAMS)

    NASA Astrophysics Data System (ADS)

    Roberts, G.; Wooster, M. J.; Xu, W.; Freeborn, P. H.; Morcrette, J.-J.; Jones, L.; Benedetti, A.; Jiangping, H.; Fisher, D.; Kaiser, J. W.

    2015-11-01

    Characterising the dynamics of landscape-scale wildfires at very high temporal resolutions is best achieved using observations from Earth Observation (EO) sensors mounted onboard geostationary satellites. As a result, a number of operational active fire products have been developed from the data of such sensors. An example of which are the Fire Radiative Power (FRP) products, the FRP-PIXEL and FRP-GRID products, generated by the Land Surface Analysis Satellite Applications Facility (LSA SAF) from imagery collected by the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard the Meteosat Second Generation (MSG) series of geostationary EO satellites. The processing chain developed to deliver these FRP products detects SEVIRI pixels containing actively burning fires and characterises their FRP output across four geographic regions covering Europe, part of South America and Northern and Southern Africa. The FRP-PIXEL product contains the highest spatial and temporal resolution FRP data set, whilst the FRP-GRID product contains a spatio-temporal summary that includes bias adjustments for cloud cover and the non-detection of low FRP fire pixels. Here we evaluate these two products against active fire data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) and compare the results to those for three alternative active fire products derived from SEVIRI imagery. The FRP-PIXEL product is shown to detect a substantially greater number of active fire pixels than do alternative SEVIRI-based products, and comparison to MODIS on a per-fire basis indicates a strong agreement and low bias in terms of FRP values. However, low FRP fire pixels remain undetected by SEVIRI, with errors of active fire pixel detection commission and omission compared to MODIS ranging between 9-13 % and 65-77 % respectively in Africa. Higher errors of omission result in greater underestimation of regional FRP totals relative to those derived from simultaneously collected MODIS

  11. Spontaneous emission and absorber theory

    NASA Astrophysics Data System (ADS)

    Pegg, David T.

    1997-01-01

    One of the long term interests of George Series was the construction of a theory of spontaneous emission which does not involve field quantisation. His approach was written in terms of atomic operators only and he drew a parallel with the Wheeler-Feynman absorber theory of radiation. By making a particular extra postulate, he was able to obtain the correct spontaneous emission rate and the Lamb shift reasonably simply and directly. An examination of his approach indicates that this postulate is physically reasonable and the need for it arises because quantisation in his theory occurs after the response of the absorber has been accounted for by means of the radiative reaction field. We review briefly an alternative absorber theory approach to spontaneous emission based on the direct action between the emitting atom and a quantised absorber, and outline some applications to more recent effects of interest in quantum optics.

  12. Guided tissue regeneration. Absorbable barriers.

    PubMed

    Wang, H L; MacNeil, R L

    1998-07-01

    Over the past 15 years, techniques aimed at regeneration of lost periodontal tissue have become widely used and accepted in clinical practice. Among these techniques are those which use the principles of guided tissue regeneration (GTR), wherein barriers (i.e., membranes) are used to control cell and tissue repopulation of the periodontal wound. A variety of non-absorbable and absorbable barriers have been developed and used for this purpose, with a trend in recent years toward increased use of absorbable GTR materials. This article describes the evolution of absorbable barrier materials and overview materials available for clinical use today. In addition, advantages and disadvantages of these materials are discussed, as well as possible new developments in barrier-based GTR therapy.

  13. Countercurrent flow absorber and desorber

    DOEpatents

    Wilkinson, W.H.

    1984-10-16

    Countercurrent flow absorber and desorber devices are provided for use in absorption cycle refrigeration systems and thermal boosting systems. The devices have increased residence time and surface area resulting in improved heat and mass transfer characteristics. The apparatuses may be incorporated into open cycle thermal boosting systems in which steam serves both as the refrigerant vapor which is supplied to the absorber section and as the supply of heat to drive the desorber section of the system. 9 figs.

  14. Countercurrent flow absorber and desorber

    DOEpatents

    Wilkinson, William H.

    1984-01-01

    Countercurrent flow absorber and desorber devices are provided for use in absorption cycle refrigeration systems and thermal boosting systems. The devices have increased residence time and surface area resulting in improved heat and mass transfer characteristics. The apparatuses may be incorporated into open cycle thermal boosting systems in which steam serves both as the refrigerant vapor which is supplied to the absorber section and as the supply of heat to drive the desorber section of the system.

  15. Perfect selective metamaterial solar absorbers.

    PubMed

    Wang, Hao; Wang, Liping

    2013-11-04

    In this work, we numerically investigate the radiative properties of metamaterial nanostructures made of two-dimensional tungsten gratings on a thin dielectric spacer and an opaque tungsten film from UV to mid-infrared region as potential selective solar absorbers. The metamaterial absorber with single-sized tungsten patches exhibits high absorptance in the visible and near-infrared region due to several mechanisms such as surface plasmon polaritons, magnetic polaritons, and intrinsic bandgap absorption of tungsten. Geometric effects on the resonance wavelengths and the absorptance spectra are studied, and the physical mechanisms are elucidated in detail. The absorptance could be further enhanced in a broader spectral range with double-sized metamaterial absorbers. The total solar absorptance of the optimized metamaterial absorbers at normal incidence could be more than 88%, while the total emittance is less than 3% at 100°C, resulting in total photon-to-heat conversion efficiency of 86% without any optical concentration. Moreover, the metamaterial solar absorbers exhibit quasi-diffuse behaviors as well as polarization independence. The results here will facilitate the design of novel highly efficient solar absorbers to enhance the performance of various solar energy conversion systems.

  16. Improved retrieval of direct and diffuse downwelling surface shortwave flux in cloudless atmosphere using dynamic estimates of aerosol content and type: application to the LSA-SAF project

    NASA Astrophysics Data System (ADS)

    Ceamanos, X.; Carrer, D.; Roujean, J.-L.

    2014-08-01

    Downwelling surface shortwave flux (DSSF) is a key parameter to addressing many climate, meteorological, and solar energy issues. Under clear sky conditions, DSSF is particularly sensitive to the variability both in time and space of the aerosol load and chemical composition. Hitherto, this dependence has not been properly addressed by the Satellite Application Facility on Land Surface Analysis (LSA-SAF), which operationally disseminates instantaneous DSSF products over the continents since 2005 considering constant aerosol conditions. In the present study, an efficient method is proposed for DSSF retrieval that will overcome the limitations of the current LSA-SAF product. This method referred to as SIRAMix (Surface Incident Radiation estimation using Aerosol Mixtures) is based upon an accurate physical parameterization coupled with a radiative transfer-based look up table of aerosol properties. SIRAMix considers a tropospheric layer composed of several major aerosol species that are conveniently mixed to reproduce real aerosol conditions as best as possible. This feature of SIRAMix allows it to provide not only accurate estimates of global DSSF but also the direct and diffuse DSSF components, which are crucial radiative terms in many climatological applications. The implementation of SIRAMix is tested in the present article using atmospheric analyses from the European Center for Medium-Range Weather Forecasts (ECMWF). DSSF estimates provided by SIRAMix are compared against instantaneous DSSF measurements taken at several ground stations belonging to several radiation measurement networks. Results show an average root mean square error (RMSE) of 23.6, 59.1, and 44.9 W m-2 for global, direct, and diffuse DSSF, respectively. These scores decrease the average RMSE obtained for the current LSA-SAF product by 18.6%, which only provides global DSSF for the time being, and, to a lesser extent, for the state of the art in the matter of DSSF retrieval (RMSE decrease of 10

  17. Role of coupled cataclasis-pressure solution deformation in microearthquake activity along the creeping segment of the SAF: Inferences from studies of the SAFOD core samples

    NASA Astrophysics Data System (ADS)

    Hadizadeh, J.; Gratier, J.; Renard, F.; Mittempregher, S.; di Toro, G.

    2009-12-01

    Rocks encountered in the SAFOD drill hole represent deformation in the southern-most extent of the creeping segment of the SAF north of the Parkfield. At the site and toward the northwest the SAF is characterized by aseismic creep as well as strain release through repeating microearthquakes M<3. The activity is shown to be mostly distributed as clusters aligned in the slip direction, and occurring at depths of between 3 to 5 kilometers. It has been suggested that the events are due to frequent moment release from high strength asperities constituting only about 1% or less of the total fault surface area within an otherwise weak fault gouge. We studied samples selected from the SAFOD phase 3 cores (3142m -3296m MD) using high resolution scanning electron microscopy, cathodoluminescence imaging, X-ray fluorescence mapping, and energy dispersive X-ray spectroscopy. The observed microstructural deformation that is apparently relevant to the seismological data includes clear evidence of cyclic deformation events, cataclastic flow, and pressure solution creep with attendant vein sealing and fracture healing fabrics. Friction testing of drill cuttings and modeling by others suggest that the overall creep behavior in shale-siltstone gouge may be due to low bulk friction coefficient of 0.2-0.4 for the fault rock. Furthermore, the low resistivity zone extending to about 5km beneath the SAFOD-Middle Mountain area is believed to consist of a pod of fluid-filled fractured and porous rocks. Our microstructural data indicate that the foliated shale-siltstone cataclasites are, in a highly heterogeneous way, more porous and permeable than the host rock and therefore provide for structurally controlled enhanced fluid-rock interactions. This is consistent with the observed pressure solution deformation and the microstructural indications of transiently high fluid pressures. We hypothesize that while the friction laws defining stable sliding are prevalent in bulk deformation of the

  18. Determination of the bioaccessible fraction of metals in urban aerosol using simulated lung fluids

    NASA Astrophysics Data System (ADS)

    Coufalík, Pavel; Mikuška, Pavel; Matoušek, Tomáš; Večeřa, Zbyněk

    2016-09-01

    Determination of the bioaccessible fraction of metals in atmospheric aerosol is a significant issue with respect to air pollution in the urban environment. The aim of this work was to compare of metal bioaccessibility determined according to the extraction yields of six simulated lung fluids. Aerosol samples of the PM1 fraction were collected in Brno, Czech Republic. The total contents of Cd, Ce, Cr, Cu, Fe, Mn, Ni, Pb, V, and Zn in the samples were determined and their enrichment factors were calculated. The bioaccessible proportions of elements were determined by means of extraction in Gamble's solution, Gamble's solution with dipalmitoyl phosphatidyl choline (DPPC), artificial lysosomal fluid, saline, water, and in a newly proposed solution based on DPPC, referred to as "Simulated Alveoli Fluid" (SAF). The chemical composition and surface tension of the simulated lung fluids were the main parameters influencing extraction yields. Gamble's solutions and the newly designed solution of SAF exhibited the lowest extraction efficiency, and also had the lowest surface tensions. The bioaccessibility of particulate metals should be assessed by synthetic lung fluids with a low surface tension, which simulate better the behavior and composition of native lung surfactant. The bioaccessibility of metals in aerosol assessed by means of the extraction in water or artificial lysosomal fluid can be overestimated.

  19. Mushroom plasmonic metamaterial infrared absorbers

    SciTech Connect

    Ogawa, Shinpei Fujisawa, Daisuke; Hata, Hisatoshi; Uetsuki, Mitsuharu; Misaki, Koji; Kimata, Masafumi

    2015-01-26

    There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF{sub 2} etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.

  20. Mushroom plasmonic metamaterial infrared absorbers

    NASA Astrophysics Data System (ADS)

    Ogawa, Shinpei; Fujisawa, Daisuke; Hata, Hisatoshi; Uetsuki, Mitsuharu; Misaki, Koji; Kimata, Masafumi

    2015-01-01

    There has been a considerable amount of interest in the development of various types of electromagnetic wave absorbers for use in different wavelength ranges. In particular, infrared (IR) absorbers with wavelength selectivity can be applied to advanced uncooled IR sensors, which would be capable of identifying objects through their radiation spectrum. In the present study, mushroom plasmonic metamaterial absorbers (MPMAs) for the IR wavelength region were designed and fabricated. The MPMAs consist of a periodic array of thin metal micropatches connected to a thin metal plate with narrow silicon (Si) posts. A Si post height of 200 nm was achieved by isotropic XeF2 etching of a thin Si layer sandwiched between metal plates. This fabrication procedure is relatively simple and is consistent with complementary metal oxide semiconductor technology. The absorption spectra of the fabricated MPMAs were experimentally measured. In addition, theoretical calculations of their absorption properties were conducted using rigorous coupled wave analysis. Both the calculated and measured absorbance results demonstrated that these MPMAs can realize strong selective absorption at wavelengths beyond the period of the array by varying the micropatch width. Absorbance values greater than 90% were achieved. Dual- or single-mode absorption can also be selected by varying the width of the Si posts. Pixel structures using such MPMAs could be used as high responsivity, high resolution and fast uncooled IR sensors.

  1. Additive manufacturing of RF absorbers

    NASA Astrophysics Data System (ADS)

    Mills, Matthew S.

    The ability of additive manufacturing techniques to fabricate integrated electromagnetic absorbers tuned for specific radio frequency bands within structural composites allows for unique combinations of mechanical and electromagnetic properties. These composites and films can be used for RF shielding of sensitive electromagnetic components through in-plane and out-of-plane RF absorption. Structural composites are a common building block of many commercial platforms. These platforms may be placed in situations in which there is a need for embedded RF absorbing properties along with structural properties. Instead of adding radar absorbing treatments to the external surface of existing structures, which adds increased size, weight and cost; it could prove to be advantageous to integrate the microwave absorbing properties directly into the composite during the fabrication process. In this thesis, a method based on additive manufacturing techniques of composites structures with prescribed electromagnetic loss, within the frequency range 1 to 26GHz, is presented. This method utilizes screen printing and nScrypt micro dispensing to pattern a carbon based ink onto low loss substrates. The materials chosen for this study will be presented, and the fabrication technique that these materials went through to create RF absorbing structures will be described. The calibration methods used, the modeling of the RF structures, and the applications in which this technology can be utilized will also be presented.

  2. Carbon Absorber Retrofit Equipment (CARE)

    SciTech Connect

    Klein, Eric

    2015-12-23

    During Project DE-FE0007528, CARE (Carbon Absorber Retrofit Equipment), Neumann Systems Group (NSG) designed, installed and tested a 0.5MW NeuStream® carbon dioxide (CO2) capture system using the patented NeuStream® absorber equipment and concentrated (6 molal) piperazine (PZ) as the solvent at Colorado Springs Utilities’ (CSU’s) Martin Drake pulverized coal (PC) power plant. The 36 month project included design, build and test phases. The 0.5MW NeuStream® CO2 capture system was successfully tested on flue gas from both coal and natural gas combustion sources and was shown to meet project objectives. Ninety percent CO2 removal was achieved with greater than 95% CO2product purity. The absorbers tested support a 90% reduction in absorber volume compared to packed towers and with an absorber parasitic power of less than 1% when configured for operation with a 550MW coal plant. The preliminary techno-economic analysis (TEA) performed by the Energy and Environmental Research Center (EERC) predicted an over-the-fence cost of $25.73/tonne of CO2 captured from a sub-critical PC plant.

  3. Low temperature selective absorber research

    NASA Astrophysics Data System (ADS)

    Herzenberg, S. A.; Silberglitt, R.

    1982-04-01

    Research carried out since 1979 on selective absorbers is surveyed, with particular attention given to the low-temperature coatings seen as promising for flat plate and evacuated tube applications. The most thoroughly investigated absorber is black chrome, which is highly selective and is the most durable low-temperature absorber. It is believed that other materials, because of their low cost and lower content of strategic materials, may eventually supplant black chrome. Among these candidates are chemically converted black nickel; anodically oxidized nickel, zinc, and copper composites; and nickel or other low-cost multilayer coatings. In reviewing medium and high-temperature research, black chrome, multilayer coatings and black cobalt are seen as best medium-temperature candidates. For high temperatures, an Al2O3/Pt-Al203 multilayer composite or the zirconium diboride coating is preferred.

  4. Magnetically tunable metamaterial perfect absorber

    NASA Astrophysics Data System (ADS)

    Lei, Ming; Feng, Ningyue; Wang, Qingmin; Hao, Yanan; Huang, Shanguo; Bi, Ke

    2016-06-01

    A magnetically tunable metamaterial perfect absorber (MPA) based on ferromagnetic resonance is experimentally and numerically demonstrated. The ferrite-based MPA is composed of an array of ferrite rods and a metallic ground plane. Frequency dependent absorption of the ferrite-based MPA under a series of applied magnetic fields is discussed. An absorption peak induced by ferromagnetic resonance appears in the range of 8-12 GHz under a certain magnetic field. Both the simulated and experimental results demonstrate that the absorption frequency of the ferrite-based MPA can be tuned by the applied magnetic field. This work provides an effective way to fabricate the magnetically tunable metamaterial perfect absorber.

  5. Adaptive inertial shock-absorber

    NASA Astrophysics Data System (ADS)

    Faraj, Rami; Holnicki-Szulc, Jan; Knap, Lech; Seńko, Jarosław

    2016-03-01

    This paper introduces and discusses a new concept of impact absorption by means of impact energy management and storage in dedicated rotating inertial discs. The effectiveness of the concept is demonstrated in a selected case-study involving spinning management, a recently developed novel impact-absorber. A specific control technique performed on this device is demonstrated to be the main source of significant improvement in the overall efficiency of impact damping process. The influence of various parameters on the performance of the shock-absorber is investigated. Design and manufacturing challenges and directions of further research are formulated.

  6. Damage tolerant light absorbing material

    DOEpatents

    Lauf, R.J.; Hamby, C. Jr.; Akerman, M.A.; Seals, R.D.

    1993-09-07

    A light absorbing article comprised of a composite of carbon-bonded carbon fibers, is prepared by: blending carbon fibers with a carbonizable organic powder to form a mixture; dispersing the mixture into an aqueous slurry; vacuum molding the aqueous slurry to form a green article; drying and curing the green article to form a cured article; and, carbonizing the cured article at a temperature of at least about 1000 C to form a carbon-bonded carbon fiber light absorbing composite article having a bulk density less than 1 g/cm[sup 3]. 9 figures.

  7. Damage tolerant light absorbing material

    DOEpatents

    Lauf, Robert J.; Hamby, Jr., Clyde; Akerman, M. Alfred; Seals, Roland D.

    1993-01-01

    A light absorbing article comprised of a composite of carbon-bonded carbon fibers, prepared by: blending carbon fibers with a carbonizable organic powder to form a mixture; dispersing the mixture into an aqueous slurry; vacuum molding the aqueous slurry to form a green article; drying and curing the green article to form a cured article; and, carbonizing the cured article at a temperature of at least about 1000.degree. C. to form a carbon-bonded carbon fiber light absorbing composite article having a bulk density less than 1 g/cm.sup.3.

  8. Counterflow absorber for an absorption refrigeration system

    DOEpatents

    Reimann, Robert C.

    1984-01-01

    An air-cooled, vertical tube absorber for an absorption refrigeration system is disclosed. Strong absorbent solution is supplied to the top of the absorber and refrigerant vapor is supplied to the bottom of the absorber to create a direct counterflow of refrigerant vapor and absorbent solution in the absorber. The refrigeration system is designed so that the volume flow rate of refrigerant vapor in the tubes of the absorber is sufficient to create a substantially direct counterflow along the entire length of each tube in the absorber. This provides several advantages for the absorber such as higher efficiency and improved heat transfer characteristics, and allows improved purging of non-condensibles from the absorber.

  9. Metamaterial Absorbers for Microwave Detection

    DTIC Science & Technology

    2015-06-01

    a) Depiction of metamaterial array of square resonators atop FR4. (b) Metamaterial dimensions and structure...comparison for varying resonator array dimension sizes. ..............23 Figure 12. Absorption derived from raw reflection data...36 x Figure 23. Metamaterial absorber array where resonator dimensions control the detection frequencies and

  10. Oil and fat absorbing polymers

    NASA Technical Reports Server (NTRS)

    Marsh, H. E., Jr. (Inventor)

    1977-01-01

    A method is described for forming a solid network polymer having a minimal amount of crosslinking for use in absorbing fats and oils. The polymer remains solid at a swelling ratio in oil or fat of at least ten and provides an oil absorption greater than 900 weight percent.

  11. Predictability of cloud fraction in global NWP models

    NASA Astrophysics Data System (ADS)

    Haiden, Thomas

    2015-04-01

    Accurate prediction of cloudiness is crucial in weather forecasting. Clouds exert a strong feedback on atmospheric flow by modulating energy fluxes and heating rates. Errors in low cloudiness contribute significantly to 2-m temperature errors in the short and medium range. It is investigated how the predictability of cloud fraction depends on cloud type and cloud fraction in different global models using ECMWF's high-resolution and ensemble forecasts, as well as the THORPEX Interactive Grand Global Ensemble (TIGGE) dataset. Results indicate that the skill of a probabilistic forecast of cloudiness exceeds that of a deterministic forecast already at shorter lead times than typically found for other surface or upper-air parameters. Systematic errors in forecasted cloud fraction distributions in different cloud regimes are analyzed in the Atlantic-Euro-African domain using Climate Monitoring Satellite Application Facility (CM SAF) data. Model development at ECMWF has been able to reduce systematic and non-systematic errors in the forecast of cloudiness over the last decade. However, gains in skill have been smaller than for other parameters, possible causes of which are discussed. A significant potential for improvement of forecasts of low cloudiness (stratocumulus, stratus) is identified.

  12. Clearance of absorbed selenium by the liver

    SciTech Connect

    Kato, Tatsuko; Read, R.; Rozga, J.; Burk, R.F. )

    1991-03-11

    The liver plays a central role in the metabolism of selenium. It secretes plasma selenoproteins, contains a major fraction of the glutathione peroxidase in the body, and synthesizes excretory metabolites. The role of the liver in processing newly absorbed selenium was studied. Male chow-fed rats were fasted overnight and given 24 ng of selenium as {sup 75}SeO{sub 3}{sup 2{minus}} by stomach tube. Animals were exsanguinated at 15, 30, 45, 60, 90, 120, and 180 min after dosing. Comparison of {sup 75}Se uptake by liver, kidney, heart, muscle, testis, brain, and spleen indicated an earlier uptake by liver than by any other tissue. At 15 min, {sup 75}Se in the portal vein blood was 2.6 times that in the hepatic vein blood. Gel filtration analysis suggested a loose association of {sup 75}Se with protein in plasma at 15 min, but immunoprecipitation indicated it was largely in the form of selenoprotein P after 30 min. End-to-side portacaval shunts (PCS) were constructed in rats and sham-operated animals were used as controls. When {sup 75}SeO{sub 3}{sup 2{minus}} was given to animals with PCS, uptake of {sup 75}Se by liver did not precede uptake by other tissues. Also no gradient was detected across the lungs or kidney. {sup 75}Se content of the kidney was higher in PCS rats than in sham-operated rats. This is consistent with removal of the first-pass effect of the liver facilitating uptake of {sup 75}Se by systemic tissues. These results suggest that the preferential uptake of absorbed selenium by the liver is due both to its position in the portal circulation and to an intrinsic high uptake capacity.

  13. Energy-Absorbing, Lightweight Wheels

    NASA Technical Reports Server (NTRS)

    Waydo, Peter

    2003-01-01

    Improved energy-absorbing wheels are under development for use on special-purpose vehicles that must traverse rough terrain under conditions (e.g., extreme cold) in which rubber pneumatic tires would fail. The designs of these wheels differ from those of prior non-pneumatic energy-absorbing wheels in ways that result in lighter weights and more effective reduction of stresses generated by ground/wheel contact forces. These wheels could be made of metals and/or composite materials to withstand the expected extreme operating conditions. As shown in the figure, a wheel according to this concept would include an isogrid tire connected to a hub via spring rods. The isogrid tire would be a stiff, lightweight structure typically made of aluminum. The isogrid aspect of the structure would both impart stiffness and act as a traction surface. The hub would be a thin-walled body of revolution having a simple or compound conical or other shape chosen for structural efficiency. The spring rods would absorb energy and partially isolate the hub and the supported vehicle from impact loads. The general spring-rod configuration shown in the figure was chosen because it would distribute contact and impact loads nearly evenly around the periphery of the hub, thereby helping to protect the hub against damage that would otherwise be caused by large loads concentrated onto small portions of the hub.

  14. Nature of the warm absorber outflow in NGC 4051

    NASA Astrophysics Data System (ADS)

    Mizumoto, Misaki; Ebisawa, Ken

    2017-04-01

    The narrow-line Seyfert 1 galaxy NGC 4051 is known to exhibit significant X-ray spectral/flux variations and have a number of emission/absorption features. X-ray observations have revealed that these absorption features are blueshifted, which indicates that NGC 4051 has warm absorber outflow. In order to constrain physical parameters of the warm absorber outflow, we analyse the archival data with the longest exposure taken by XMM-Newton in 2009. We calculate the root-mean-square (rms) spectra with the grating spectral resolution for the first time. The rms spectra have a sharp peak and several dips, which can be explained by variable absorption features and non-variable emission lines; a lower ionized warm absorber (WA1: log ξ = 1.5, v = -650 km s-1) shows large variability, whereas higher ionized warm absorbers (WA2: log ξ = 2.5, v = -4100 km s-1, WA3: log ξ = 3.4, v = -6100 km s-1) show little variability. WA1 shows the maximum variability at a time-scale of ∼104 s, suggesting that the absorber locates at ∼103 times of the Schwarzschild radius. The depth of the absorption features due to WA1 and the observed soft X-ray flux are anticorrelated in several observational sequences, which can be explained by variation of partial covering fraction of the double-layer blobs that are composed of the Compton-thick core and the ionized layer (=WA1). WA2 and WA3 show little variability and presumably extend uniformly in the line of sight. The present result shows that NGC 4051 has two types of the warm absorber outflows; the static, high-ionized and extended line-driven disc winds and the variable, low-ionized and clumpy double-layer blobs.

  15. Shock absorber operates over wide range

    NASA Technical Reports Server (NTRS)

    Creasy, W. K.; Jones, J. C.

    1965-01-01

    Piston-type hydraulic shock absorber, with a metered damping system, operates over a wide range of kinetic energy loading rates. It is used for absorbing shock and vibration on mounted machinery and heavy earth-moving equipment.

  16. 21 CFR 872.6050 - Saliva absorber.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... absorber is a device made of paper or cotton intended to absorb moisture from the oral cavity during dental... manufacturing practice requirements of the quality system regulation in part 820 of this chapter, with...

  17. Why muscle is an efficient shock absorber.

    PubMed

    Ferenczi, Michael A; Bershitsky, Sergey Y; Koubassova, Natalia A; Kopylova, Galina V; Fernandez, Manuel; Narayanan, Theyencheri; Tsaturyan, Andrey K

    2014-01-01

    Skeletal muscles power body movement by converting free energy of ATP hydrolysis into mechanical work. During the landing phase of running or jumping some activated skeletal muscles are subjected to stretch. Upon stretch they absorb body energy quickly and effectively thus protecting joints and bones from impact damage. This is achieved because during lengthening, skeletal muscle bears higher force and has higher instantaneous stiffness than during isometric contraction, and yet consumes very little ATP. We wish to understand how the actomyosin molecules change their structure and interaction to implement these physiologically useful mechanical and thermodynamical properties. We monitored changes in the low angle x-ray diffraction pattern of rabbit skeletal muscle fibers during ramp stretch compared to those during isometric contraction at physiological temperature using synchrotron radiation. The intensities of the off-meridional layer lines and fine interference structure of the meridional M3 myosin x-ray reflection were resolved. Mechanical and structural data show that upon stretch the fraction of actin-bound myosin heads is higher than during isometric contraction. On the other hand, the intensities of the actin layer lines are lower than during isometric contraction. Taken together, these results suggest that during stretch, a significant fraction of actin-bound heads is bound non-stereo-specifically, i.e. they are disordered azimuthally although stiff axially. As the strong or stereo-specific myosin binding to actin is necessary for actin activation of the myosin ATPase, this finding explains the low metabolic cost of energy absorption by muscle during the landing phase of locomotion.

  18. Constraining MHD Disk-Winds with X-ray Absorbers

    NASA Astrophysics Data System (ADS)

    Fukumura, Keigo; Tombesi, F.; Shrader, C. R.; Kazanas, D.; Contopoulos, J.; Behar, E.

    2014-01-01

    From the state-of-the-art spectroscopic observations of active galactic nuclei (AGNs) the robust features of absorption lines (e.g. most notably by H/He-like ions), called warm absorbers (WAs), have been often detected in soft X-rays (< 2 keV). While the identified WAs are often mildly blueshifted to yield line-of-sight velocities up to ~100-3,000 km/sec in typical X-ray-bright Seyfert 1 AGNs, a fraction of Seyfert galaxies such as PG 1211+143 exhibits even faster absorbers (v/ 0.1-0.2) called ultra-fast outflows (UFOs) whose physical condition is much more extreme compared with the WAs. Motivated by these recent X-ray data we show that the magnetically- driven accretion-disk wind model is a plausible scenario to explain the characteristic property of these X-ray absorbers. As a preliminary case study we demonstrate that the wind model parameters (e.g. viewing angle and wind density) can be constrained by data from PG 1211+143 at a statistically significant level with chi-squared spectral analysis. Our wind models can thus be implemented into the standard analysis package, XSPEC, as a table spectrum model for general analysis of X-ray absorbers.

  19. Recycling of waste tyre rubber into oil absorbent.

    PubMed

    Wu, B; Zhou, M H

    2009-01-01

    The abundant and indiscriminant disposal of waste tyres has caused both health and environmental problems. In this work, we provide a new way to dispose off waste tyres by reusing the waste tyre rubber (WTR) for oil absorptive material production. To investigate this feasibility, a series of absorbents were prepared by graft copolymerization-blending method, using waste tyre rubber and 4-tert-butylstyrene (tBS) as monomers. Divinylbenzene (DVB) and benzoyl peroxide (BPO) were employed as crosslinker and initiator, respectively. The existence of graft-blends (WTR-g-tBS) was determined by FTIR spectrometry and verified using thin-layer chromatography (TLC). In addition, the thermal properties of WTR-g-tBS were confirmed by a thermogravimetric analyzer (TGA). Oil absorbency of the grafted-blends increased with increases in either feed ratio of WTR to tBS or DVB concentration. This absorbency reached a maximum of 24.0gg(-1) as the feed ratio and DVB concentration were 60/40 and 1wt%, respectively, after which it decreased. At other ratios and concentrations the absorbency decreased. The gel fraction of grafted-blends increased with increasing concentration of DVB. Oil-absorption processes in pure toluene and crude oil diluted with toluene were found to adhere to first-order absorption kinetics. Furthermore, the oil-absorption rate in diluted crude oil was observed to be lower than pure toluene.

  20. Prediction of trapping rates in mixtures of partially absorbing spheres

    NASA Astrophysics Data System (ADS)

    Kansal, Anuraag R.; Torquato, Salvatore

    2002-06-01

    The combined effects of diffusion and reaction in heterogeneous media govern the behavior of a wide variety of physical and biological phenomena, including the consumption of nutrients by cells and the study of magnetic relaxation in tissues. We have considered the so-called "trapping problem," in which diffusion takes place exterior to a collection of fixed traps while reaction occurs at their surface. A simulation technique for predicting the overall trapping rate for systems of partially absorbing spherical traps based on the first-passage spheres method is presented. Using data obtained by applying this simulation technique, we then consider the problem of mixtures of partially absorbing traps. By hypothesizing a method for reducing a general mixture of traps to a mixture of perfect absorbers and perfect reflectors (i.e., reducing the dimensionality of the space of variables), we are able to accurately predict the effective surface rate constant and the trapping rate for an arbitrary mixture of partially absorbing traps. Remarkably, we find that a single, nearly universal curve allows accurate predictions to be made over a wide range of trap volume fractions and even for different trap distributions.

  1. Improving the laboratory monitoring of absorbent oil

    SciTech Connect

    V.S. Shved; S.S. Sychev; I.V. Safina; S.A. Klykov

    2009-05-15

    The performance of absorbent coal tar oil is analyzed as a function of the constituent and group composition. The qualitative and quantitative composition of the oil that ensures the required absorbent properties is determined. Operative monitoring may be based on absorbent characteristics that permit regulation of the beginning and end of regeneration.

  2. Porcelain enamel neutron absorbing material

    DOEpatents

    Iverson, Daniel C.

    1990-02-06

    A porcelain enamel composition as a neutron absorbing material can be prepared of a major proportion by weight of a cadmium compound and a minor proportion of compounds of boron, lithium and silicon. These compounds in the form of a porcelain enamel coating or layer on several alloys has been found to be particularly effective in enhancing the nuclear safety of equipment for use in the processing and storage of fissile material. The composition of the porcelain enamel coating can be tailored to match the coefficient of thermal expansion of the equipment to be coated and excellent coating adhesion can be achieved.

  3. Porcelain enamel neutron absorbing material

    DOEpatents

    Iverson, D.C.

    1987-11-20

    A porcelain enamel composition as a neutron absorbing material can be prepared of a major proportion by weight of a cadmium compound and a minor proportion of compound of boron, lithium and silicon. These compounds in the form of a porcelain enamel coating or layer on several alloys has been found to be particularly effective in enhancing the nuclear safety of equipment for use in the processing and storage of fissile material. The composition of the porcelain enamel coating can be tailored to match the coefficient of thermal expansion of the equipment to be coated and excellent coating adhesion can be achieved. 2 figs.

  4. Porcelain enamel neutron absorbing material

    DOEpatents

    Iverson, Daniel C.

    1990-01-01

    A porcelain enamel composition as a neutron absorbing material can be prepared of a major proportion by weight of a cadmium compound and a minor proportion of compounds of boron, lithium and silicon. These compounds in the form of a porcelain enamel coating or layer on several alloys has been found to be particularly effective in enhancing the nuclear safety of equipment for use in the processing and storage of fissile material. The composition of the porcelain enamel coating can be tailored to match the coefficient of thermal expansion of the equipment to be coated and excellent coating adhesion can be achieved.

  5. Light absorbing carbon emissions from commercial shipping

    NASA Astrophysics Data System (ADS)

    Lack, Daniel; Lerner, Brian; Granier, Claire; Baynard, Tahllee; Lovejoy, Edward; Massoli, Paola; Ravishankara, A. R.; Williams, Eric

    2008-07-01

    Extensive measurements of the emission of light absorbing carbon aerosol (LAC) from commercial shipping are presented. Vessel emissions were sampled using a photoacoustic spectrometer in the Gulf of Mexico region. The highest emitters (per unit fuel burnt) are tug boats, thus making significant contributions to local air quality in ports. Emission of LAC from cargo and non cargo vessels in this study appears to be independent of engine load. Shipping fuel consumption data (2001) was used to calculate a global LAC contribution of 133(+/-27) Ggyr-1, or ~1.7% of global LAC. This small fraction could have disproportionate effects on both air quality near port areas and climate in the Arctic if direct emissions of LAC occur in that region due to opening Arctic sea routes. The global contribution of this LAC burden was investigated using the MOZART model. Increases of 20-50 ng m-3 LAC (relative increases up to 40%) due to shipping occur in the tropical Atlantic, Indonesia, central America and the southern regions of South America and Africa.

  6. Absorber Coatings for Mid-Infrared Astrophysics

    NASA Astrophysics Data System (ADS)

    Baker, Dahlia Anne; Wollack, Edward; Rostem, Karwan

    2017-01-01

    Control over optical response is an important aspect of instrument design for astrophysical imaging. Here we consider a mid-infrared absorber coating proposed for use on HIRMES (High Resolution Mid-Infrared Spectrometer), a cryogenic spectrometer which will fly on the SOFIA (Stratospheric Observatory for Infrared Astronomy) aircraft. The aim of this effort is to develop an absorptive coating for the 20-200 microns spectral range based on a graphene loaded epoxy binder (Epotek 377H) and glass microsphere scatterers (3M K1). The coatings electromagnetic response was modeled using a Matlab script and the glass microspheres were characterized by the measured size distribution, the dielectric constant, and the filling fraction. Images of the microspheres taken by a microscope were used to determine the size distribution with an ImageJ particle analysis program. Representative test samples for optical evaluation were fabricated for characterization via infrared Fourier transform spectroscopy. The optical tests will determine the material’s absorptance and reflectance. These test results will be compared to the modeled response.

  7. Carbon dioxide absorbents for rebreather diving.

    PubMed

    Pennefather, John

    2016-09-01

    Firstly I would like to thank SPUMS members for making me a Life Member of SPUMS; I was surprised and greatly honoured by the award. I also want to confirm and expand on the findings on carbon dioxide absorbents reported by David Harvey et al. For about 35 years, I was the main player in deciding which absorbent went into Australian Navy and Army diving sets. On several occasions, suppliers of absorbents to the anaesthesia market tried to supply the Australian military market. On no occasion did they provide absorbent that came close to the minimum absorbent capacity required, generally being 30-40% less efficient than diving-grade absorbents. Because I regard lives as being more important than any likely dollar saving, the best absorbent was always selected unless two suppliers provided samples with the same absorbent capacity. On almost every occasion, there was a clear winner and cost was never considered. I suggest the same argument for the best absorbent should be used by members and their friends who dive using rebreather sets. I make this point because of my findings on a set that was brought to me after the death of its owner. The absorbent was not the type or grain size recommended by the manufacturer of the set and did not resemble any of the diving grade absorbents I knew of. I suspected by its appearance that it was anaesthetic grade absorbent. When I tested the set, the absorbent system failed very quickly so it is likely that carbon dioxide toxicity contributed to his death. The death was not the subject of an inquest and I have no knowledge of how the man obtained the absorbent. Possibly there was someone from an operating theatre staff who unintentionally caused their friend's death by supplying him with 'borrowed absorbent'. I make this point as I would like to discourage members from making a similar error.

  8. Light-absorbing impurities in Arctic snow

    NASA Astrophysics Data System (ADS)

    Doherty, S. J.; Warren, S. G.; Grenfell, T. C.; Clarke, A. D.; Brandt, R. E.

    2010-12-01

    Absorption of radiation by ice is extremely weak at visible and near-ultraviolet wavelengths, so small amounts of light-absorbing impurities in snow can dominate the absorption of solar radiation at these wavelengths, reducing the albedo relative to that of pure snow, contributing to the surface energy budget and leading to earlier snowmelt. In this study Arctic snow is surveyed for its content of light-absorbing impurities, expanding and updating the 1983-1984 survey of Clarke and Noone. Samples were collected in Alaska, Canada, Greenland, Svalbard, Norway, Russia, and the Arctic Ocean during 1998 and 2005-2009, on tundra, glaciers, ice caps, sea ice, frozen lakes, and in boreal forests. Snow was collected mostly in spring, when the entire winter snowpack is accessible for sampling. Sampling was carried out in summer on the Greenland Ice Sheet and on the Arctic Ocean, of melting glacier snow and sea ice as well as cold snow. About 1200 snow samples have been analyzed for this study. The snow is melted and filtered; the filters are analyzed in a specially designed spectrophotometer system to infer the concentration of black carbon (BC), the fraction of absorption due to non-BC light-absorbing constituents and the absorption Ångstrom exponent of all particles. This is done using BC calibration standards having a mass absorption efficiency of 6.0 m2 g-1 at 550 nm and by making an assumption that the absorption Angstrom exponent for BC is 1.0 and for non-BC light-absorbing aerosol is 5.0. The reduction of snow albedo is primarily due to BC, but other impurities, principally brown (organic) carbon, are typically responsible for ~40% of the visible and ultraviolet absorption. The meltwater from selected snow samples was saved for chemical analysis to identify sources of the impurities. Median BC amounts in surface snow are as follows (nanograms of carbon per gram of snow): Greenland 3, Arctic Ocean snow 7, melting sea ice 8, Arctic Canada 8, subarctic Canada 14

  9. A polarization-independent broadband terahertz absorber

    SciTech Connect

    Shi, Cheng; Zang, XiaoFei E-mail: ymzhu@usst.edu.cn; Wang, YiQiao; Chen, Lin; Cai, Bin; Zhu, YiMing E-mail: ymzhu@usst.edu.cn

    2014-07-21

    A highly efficient broadband terahertz absorber is designed, fabricated, and experimentally as well as theoretically evaluated. The absorber comprises a heavily doped silicon substrate and a well-designed two-dimensional grating. Due to the destructive interference of waves and diffraction, the absorber can achieve over 95% absorption in a broad frequency range from 1 to 2 THz and for angles of incidence from 0° to 60°. Such a terahertz absorber is also polarization-independent due to its symmetrical structure. This omnidirectional and broadband absorber have potential applications in anti-reflection coatings, imaging systems, and so on.

  10. Spatial heterogeneity in vegetation canopies and remote sensing of absorbed photosynthetically active radiation - A modeling study

    NASA Technical Reports Server (NTRS)

    Asrar, G.; Myneni, R. B.; Choudhury, B. J.

    1992-01-01

    A 3D radiative transfer model is used to investigate the relationship between spectral indices and fraction of absorbed photosynthetically active radiation (PAR) in horizontally heterogeneous vegetation canopies. Canopy reflection at optical wavelengths and PAR absorption are simulated. Data obtained indicate that the leaf area index of a canopy is less of an instructive parameter than the ground cover and clump leaf area index for these canopies. It is found that the relationship between the normalized difference vegetation index and fraction of absorbed PAR is almost linear and independent of spatial heterogeneity.

  11. Fractional vector calculus and fractional Maxwell's equations

    SciTech Connect

    Tarasov, Vasily E.

    2008-11-15

    The theory of derivatives and integrals of non-integer order goes back to Leibniz, Liouville, Grunwald, Letnikov and Riemann. The history of fractional vector calculus (FVC) has only 10 years. The main approaches to formulate a FVC, which are used in the physics during the past few years, will be briefly described in this paper. We solve some problems of consistent formulations of FVC by using a fractional generalization of the Fundamental Theorem of Calculus. We define the differential and integral vector operations. The fractional Green's, Stokes' and Gauss's theorems are formulated. The proofs of these theorems are realized for simplest regions. A fractional generalization of exterior differential calculus of differential forms is discussed. Fractional nonlocal Maxwell's equations and the corresponding fractional wave equations are considered.

  12. Initialized Fractional Calculus

    NASA Technical Reports Server (NTRS)

    Lorenzo, Carl F.; Hartley, Tom T.

    2000-01-01

    This paper demonstrates the need for a nonconstant initialization for the fractional calculus and establishes a basic definition set for the initialized fractional differintegral. This definition set allows the formalization of an initialized fractional calculus. Two basis calculi are considered; the Riemann-Liouville and the Grunwald fractional calculi. Two forms of initialization, terminal and side are developed.

  13. New calculations for internal dosimetry of beta-emitting radiopharmaceuticals.

    PubMed

    Zankl, M; Petoussi-Henss, N; Janzen, T; Uusijärvi, H; Schlattl, H; Li, W B; Giussani, A; Hoeschen, C

    2010-01-01

    The calculation of absorbed dose from internally incorporated radionuclides is based on the so-called specific absorbed fractions (SAFs) which represent the fraction of energy emitted in a given source region that is absorbed per unit mass in a specific target organ. Until recently, photon SAFs were calculated using MIRD-type mathematical phantoms. For electrons, the energy released was assumed to be absorbed locally ('ICRP 30 approach'). For this work, photon and electron SAFs were derived with Monte Carlo simulations in the new male voxel-based reference computational phantom adopted by the ICRP and ICRU. The present results show that the assumption of electrons being locally absorbed is not always true at energies above 300-500 keV. For source/target organ pairs in close vicinity, high-energy electrons escaping from the source organ may result in cross-fire electron SAFs in the same order of magnitude as those from photons. Examples of organ absorbed doses per unit activity are given for (18)F-choline and (123)I-iodide. The impact of the new electron SAFs used for absorbed dose calculations compared with the previously used assumptions was found to be small. The organ dose coefficients for the two approaches differ by not more than 6 % for most organs. Only for irradiation of the urinary bladder wall by activity in the contents, the ICRP 30 approach presents an overestimation of approximately 40-50%.

  14. Liquid crystal tunable metamaterial absorber.

    PubMed

    Shrekenhamer, David; Chen, Wen-Chen; Padilla, Willie J

    2013-04-26

    We present an experimental demonstration of electronically tunable metamaterial absorbers in the terahertz regime. By incorporation of active liquid crystal into strategic locations within the metamaterial unit cell, we are able to modify the absorption by 30% at 2.62 THz, as well as tune the resonant absorption over 4% in bandwidth. Numerical full-wave simulations match well to experiments and clarify the underlying mechanism, i.e., a simultaneous tuning of both the electric and magnetic response that allows for the preservation of the resonant absorption. These results show that fundamental light interactions of surfaces can be dynamically controlled by all-electronic means and provide a path forward for realization of novel applications.

  15. Tempered fractional calculus

    SciTech Connect

    Sabzikar, Farzad; Meerschaert, Mark M.; Chen, Jinghua

    2015-07-15

    Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered fractional difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series.

  16. Decadal changes in downward shortwave radiation from a satellite-derived CM SAF product and ground-based observations over Europe

    NASA Astrophysics Data System (ADS)

    Sanchez-Lorenzo, Arturo; Wild, Martin; Trentmann, Jörg; Enriquez-Alonso, Aaron; Pfeifroth, Uwe; Manara, Veronica

    2016-04-01

    Trends of downward shortwave radiation (DSR) from high-spatial resolution satellite-derived data over Europe since 1983 are first presented based on a Satellite Application Facility on Climate Monitoring (CM SAF) surface radiation data set, which is derived from the Meteosat geostationary satellites. The results show a widespread brightening in the major part of Europe, especially since the mid-1990s and in springtime. There is a mean increase of SSR of around 2 Wm-2 per decade over the whole Europe, which, taking into account that the satellite-derived product lacks of aerosol variations, can be related to a decrease in the cloud radiative effects over Europe. The reported increase in SSR is slightly lower than the obtained using high-quality ground-based series over Europe. Secondly, residual series have been derived as the result of the difference between ground-based and satellite-derived all-sky SSR data. The residual mean series points to a significant increase during the period 1983-2010, with higher rates of around 2 Wm-2 per decade over central and eastern Europe. The spatial variation of these residual time series seem to be in line with observed clear-sky SSR and anthropogenic aerosol loading trends and are not just explained by inhomogeneities in the satellite-derived product. This increase in the residual series is mainly due to a strong increase from the mid-1980s to the late 1990s, thus possibly linked to a decrease in anthropogenic emissions and a recovery from the El Chichón and Pinatubo volcanic eruptions.

  17. Global surface solar irradiance product derived from SCIAMACHY FRESCO cloud fraction

    NASA Astrophysics Data System (ADS)

    Wang, Ping; Stammes, Piet; Müller, Richard

    The FRESCO cloud retrieval algorithm has been developed as a simple but fast and efficient algorithm for GOME and SCIAMACHY (Koelemeijer et al., 2001; Fournier et al., 2006; Wang et al., 2008). FRESCO employs the O2 A band at 760 nm to retrieve the effective cloud fraction and cloud pressure using a simple Lambertian cloud model. The effective cloud fraction is a combination of geometric cloud fraction and cloud optical thickness, which yield the same reflectance at the top of the atmosphere as the cloud in the scene. It is well-known that clouds reduce the surface solar irradiance. Therefore the all-sky irradiance can be derived from the clear-sky irradiance with a scaling factor related to the cloud index. The cloud index is very similar to the effective cloud fraction by definition. The MAGIC (Mesoscale Atmospheric Global Irradiance Code) software converts the cloud index to the surface solar irradiance using the Heliosat method (Mueller et al. 2009). The MAGIC algorithm is also used by the CM-SAF surface solar irradiance product for clear sky cases. We applied the MAGIC software to FRESCO effective cloud fraction with slight modifications. In this presentation we will show the FRESCO-SSI monthly mean product and the comparison with the BSRN global irradiance data at Cabauw, the Netherlands and surface solar irradiance measurement at Tibetan plateau in China.

  18. Electromagnetic scattering by pyramidal and wedge absorber

    NASA Technical Reports Server (NTRS)

    Dewitt, Brian T.; Burnside, Walter D.

    1988-01-01

    Electromagnetic scattering from pyramidal and wedge absorbers used to line the walls of modern anechoic chambers is measured and compared with theoretically predicted values. The theoretical performance for various angles of incidence is studied. It is shown that a pyramidal absorber scatters electromagnetic energy more as a random rough surface does. The apparent reflection coefficient from an absorber wall illuminated by a plane wave can be much less than the normal absorber specifications quoted by the manufacturer. For angles near grazing incidence, pyramidal absorbers give a large backscattered field from the pyramid side-faces or edges. The wedge absorber was found to give small backscattered fields for near-grazing incidence. Based on this study, some new guidelines for the design of anechoic chambers are advocated because the specular scattering models used at present do not appear valid for pyramids that are large compared to the wavelength.

  19. Magnetic field effects on microwave absorbing materials

    NASA Technical Reports Server (NTRS)

    Goldberg, Ira; Hollingsworth, Charles S.; Mckinney, Ted M.

    1991-01-01

    The objective of this program was to gather information to formulate a microwave absorber that can work in the presence of strong constant direct current (DC) magnetic fields. The program was conducted in four steps. The first step was to investigate the electrical and magnetic properties of magnetic and ferrite microwave absorbers in the presence of strong magnetic fields. This included both experimental measurements and a literature survey of properties that may be applicable to finding an appropriate absorbing material. The second step was to identify those material properties that will produce desirable absorptive properties in the presence of intense magnetic fields and determine the range of magnetic field in which the absorbers remain effective. The third step was to establish ferrite absorber designs that will produce low reflection and adequate absorption in the presence of intense inhomogeneous static magnetic fields. The fourth and final step was to prepare and test samples of such magnetic microwave absorbers if such designs seem practical.

  20. Light-absorbing impurities in Arctic snow

    NASA Astrophysics Data System (ADS)

    Doherty, S. J.; Warren, S. G.; Grenfell, T. C.; Clarke, A. D.; Brandt, R. E.

    2010-08-01

    Absorption of radiation by ice is extremely weak at visible and near-ultraviolet wavelengths, so small amounts of light-absorbing impurities in snow can dominate the absorption of solar radiation at these wavelengths, reducing the albedo relative to that of pure snow, contributing to the surface energy budget and leading to earlier snowmelt. In this study Arctic snow is surveyed for its content of light-absorbing impurities, expanding and updating the 1983-1984 survey of Clarke and Noone. Samples were collected in Alaska, Canada, Greenland, Svalbard, Norway, Russia, and the Arctic Ocean during 2005-2009, on tundra, glaciers, ice caps, sea ice, frozen lakes, and in boreal forests. Snow was collected mostly in spring, when the entire winter snowpack is accessible for sampling. Sampling was carried out in summer on the Greenland ice sheet and on the Arctic Ocean, of melting glacier snow and sea ice as well as cold snow. About 1200 snow samples have been analyzed for this study. The snow is melted and filtered; the filters are analyzed in a specially designed spectrophotometer system to infer the concentration of black carbon (BC), the fraction of absorption due to non-BC light-absorbing constituents and the absorption Ångstrom exponent of all particles. The reduction of snow albedo is primarily due to BC, but other impurities, principally brown (organic) carbon, are typically responsible for ~40% of the visible and ultraviolet absorption. The meltwater from selected snow samples was saved for chemical analysis to identify sources of the impurities. Median BC amounts in surface snow are as follows (nanograms of carbon per gram of snow): Greenland 3, Arctic Ocean snow 7, melting sea ice 8, Arctic Canada 8, Subarctic Canada 14, Svalbard 13, Northern Norway 21, Western Arctic Russia 26, Northeastern Siberia 17. Concentrations are more variable in the European Arctic than in Arctic Canada or the Arctic Ocean, probably because of the proximity to BC sources. Individual

  1. Fraction Sense: Foundational Understandings.

    PubMed

    Fennell, Francis Skip; Karp, Karen

    2016-08-09

    The intent of this commentary is to identify elements of fraction sense and note how the research studies provided in this special issue, in related but somewhat different ways, validate the importance of such understandings. Proficiency with fractions serves as a prerequisite for student success in higher level mathematics, as well as serving as a gateway to many occupations and varied contexts beyond the mathematics classroom. Fraction sense is developed through instructional opportunities involving fraction equivalence and magnitude, comparing and ordering fractions, using fraction benchmarks, and computational estimation. Such foundations are then extended to operations involving fractions and decimals and applications involving proportional reasoning. These components of fraction sense are all addressed in the studies provided in this issue, with particular consideration devoted to the significant importance of the use of the number line as a central representational tool for conceptually understanding fraction magnitude.

  2. TEMPERED FRACTIONAL CALCULUS

    PubMed Central

    MEERSCHAERT, MARK M.; SABZIKAR, FARZAD; CHEN, JINGHUA

    2014-01-01

    Fractional derivatives and integrals are convolutions with a power law. Multiplying by an exponential factor leads to tempered fractional derivatives and integrals. Tempered fractional diffusion equations, where the usual second derivative in space is replaced by a tempered fractional derivative, govern the limits of random walk models with an exponentially tempered power law jump distribution. The limiting tempered stable probability densities exhibit semi-heavy tails, which are commonly observed in finance. Tempered power law waiting times lead to tempered fractional time derivatives, which have proven useful in geophysics. The tempered fractional derivative or integral of a Brownian motion, called a tempered fractional Brownian motion, can exhibit semi-long range dependence. The increments of this process, called tempered fractional Gaussian noise, provide a useful new stochastic model for wind speed data. A tempered difference forms the basis for numerical methods to solve tempered fractional diffusion equations, and it also provides a useful new correlation model in time series. PMID:26085690

  3. Absorbent product and articles made therefrom

    NASA Technical Reports Server (NTRS)

    Dawn, F. S.; Correale, J. V. (Inventor)

    1982-01-01

    A multilayer absorbent product for use in contact with the skin to absorb fluids is described. The product has a water pervious facing layer for contacting the skin, and a first fibrous wicking layer overlaying the water pervious layer. A first container section is defined by inner and outer layers of a water pervious wicking material in between a first absorbent mass and a second container section defined by inner and outer layers of a water pervious wicking material between what is disposed a second absorbent mass, and a liquid impermeable/gas permeable layer overlaying the second fibrous wicking layer.

  4. Nonlinear dynamic vibration absorbers with a saturation

    NASA Astrophysics Data System (ADS)

    Febbo, M.; Machado, S. P.

    2013-03-01

    The behavior of a new type of nonlinear dynamic vibration absorber is studied. A distinctive characteristic of the proposed absorber is the impossibility to extend the system to infinity. The mathematical formulation is based on a finite extensibility nonlinear elastic potential to model the saturable nonlinearity. The absorber is attached to a single degree-of-freedom linear/nonlinear oscillator subjected to a periodic external excitation. In order to solve the equations of motion and to analyze the frequency-response curves, the method of averaging is used. The performance of the FENE absorber is evaluated considering a variation of the nonlinearity of the primary system, the damping and the linearized frequency of the absorber and the mass ratio. The numerical results show that the proposed absorber has a very good efficiency when the nonlinearity of the primary system increases. When compared with a cubic nonlinear absorber, for a large nonlinearity of the primary system, the FENE absorber shows a better effectiveness for the whole studied frequency range. A complete absence of quasi-periodic oscillations is also found for an appropriate selection of the parameters of the absorber. Finally, direct integrations of the equations of motion are performed to verify the accuracy of the proposed method.

  5. Metamaterial absorber with random dendritic cells

    NASA Astrophysics Data System (ADS)

    Zhu, Weiren; Zhao, Xiaopeng

    2010-05-01

    The metamaterial absorber composed of random dendritic cells has been investigated at microwave frequencies. It is found that the absorptivities come to be weaker and the resonant frequency get red shift as the disordered states increasing, however, the random metamaterial absorber still presents high absorptivity more than 95%. The disordered structures can help understanding of the metamaterial absorber and may be employed for practical design of infrared metamaterial absorber, which may play important roles in collection of radiative heat energy and directional transfer enhancement.

  6. Device for absorbing mechanical shock

    DOEpatents

    Newlon, C.E.

    1979-08-29

    This invention is a comparatively inexpensive but efficient shock-absorbing device having special application to the protection of shipping and storage cylinders. In a typical application, two of the devices are strapped to a cylinder to serve as saddle-type supports for the cylinder during storage and to protect the cylinder in the event it is dropped during lifting or lowering operations. In its preferred form, the invention includes a hardwood plank whose grain runs in the longitudinal direction. The basal portion of the plank is of solid cross-section, whereas the upper face of the plank is cut away to form a concave surface fittable against the sidewall of a storage cylinder. The concave surface is divided into a series of segments by transversely extending, throughgoing relief slots. A layer of elastomeric material is positioned on the concave face, the elastomer being extrudable into slots when pressed against the segments by a preselected pressure characteristic of a high-energy impact. The compressive, tensile, and shear properties of the hardwood and the elastomer are utilized in combination to provide a surprisingly high energy-absorption capability.

  7. Device for absorbing mechanical shock

    DOEpatents

    Newlon, Charles E.

    1980-01-01

    This invention is a comparatively inexpensive but efficient shock-absorbing device having special application to the protection of shipping and storage cylinders. In a typical application, two of the devices are strapped to a cylinder to serve as saddle-type supports for the cylinder during storage and to protect the cylinder in the event it is dropped during lifting or lowering operations. In its preferred form, the invention includes a hardwood plank whose grain runs in the longitudinal direction. The basal portion of the plank is of solid cross-section, whereas the upper face of the plank is cut away to form a concave surface fittable against the sidewall of a storage cylinder. The concave surface is divided into a series of segments by transversely extending, throughgoing relief slots. A layer of elastomeric material is positioned on the concave face, the elastomer being extrudable into slots when pressed against the segments by a preselected pressure characteristic of a high-energy impact. The compressive, tensile, and shear properties of the hardwood and the elastomer are utilized in combination to provide a surprisingly high energy-absorption capability.

  8. Absorbencies of six different rodent beddings: commercially advertised absorbencies are potentially misleading.

    PubMed

    Burn, C C; Mason, G J

    2005-01-01

    Moisture absorbency is one of the most important characteristics of rodent beddings for controlling bacterial growth and ammonia production. However, bedding manufacturers rarely provide information on the absorbencies of available materials, and even when they do, absorption values are usually expressed per unit mass of bedding. Since beddings are usually placed into cages to reach a required depth rather than a particular mass, their volumetric absorbencies are far more relevant. This study therefore compared the saline absorbencies of sawdust, aspen woodchips, two virgin loose pulp beddings (Alpha-Dri and Omega-Dri), reclaimed wood pulp (Tek-Fresh), and corncob, calculated both by volume and by mass. Absorbency per unit volume correlated positively with bedding density, while absorbency per unit mass correlated negatively. Therefore, the relative absorbencies of the beddings were almost completely reversed depending on how absorbency was calculated. By volume, corncob was the most absorbent bedding, absorbing about twice as much saline as Tek-Fresh, the least absorbent bedding. Conversely, when calculated by mass, Tek-Fresh appeared to absorb almost three times as much saline as the corncob. Thus, in practical terms the most absorbent bedding here was corncob, followed by the loose pulp beddings; and this is generally supported by their relatively low ammonia production as seen in previous studies. Many factors other than absorbency determine whether a material is suitable as a rodent bedding, and they are briefly mentioned here. However, manufacturers should provide details of bedding absorbencies in terms of volume, in order to help predict the relative absorbencies of the beddings in practical situations.

  9. DIY Fraction Pack.

    ERIC Educational Resources Information Center

    Graham, Alan; Graham, Louise

    2003-01-01

    Describes a very successful attempt to teach fractions to year 5 pupils based on pupils making their own fraction pack. Children decided for themselves how to make the fractional slices used in the activity using colored cardboard sheets and templates of a paper circle consisting of 24 equal slices. (Author/NB)

  10. An ultrathin dual-band metamaterial absorber

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Duan, Junping; Zhang, Wendong; Wang, Wanjun; Zhang, Binzhen

    2016-10-01

    The design and preparation of an ultrathin dual-band metamaterial absorber whose resonant frequency located at radar wave (20 GHz-60 GHz) is presented in this paper. The absorber is composed of a 2-D periodic sandwich featured with two concentric annuluses. The influence on the absorber's performance produced by resonant cell's structure size and material parameters was numerically simulated and analyzed based on the standard full wave finite integration technology in CST. Laser ablation process was adopted to prepare the designed absorber on epoxy resin board coated with on double plane of copper with a thickness that is 1/30 and 1/50 of the resonant wavelength at a resonant frequency of 30.51 GHz and 48.15 GHz. The full width at half maximum (FWHM) reached 2.2 GHz and 2.35 GHz and the peak of the absorptance reached 99.977%. The ultrathin absorber is nearly omnidirectional for all polarizations. The test results of prepared sample testify the designed absorber's excellent absorbing performance forcefully. The absorber expands inspirations of radar stealth in military domain due to its flexible design, cost-effective and other outstanding properties.

  11. 21 CFR 872.6050 - Saliva absorber.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Saliva absorber. 872.6050 Section 872.6050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6050 Saliva absorber. (a) Identification. A...

  12. 21 CFR 872.6050 - Saliva absorber.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Saliva absorber. 872.6050 Section 872.6050 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6050 Saliva absorber. (a) Identification. A...

  13. [Absorbed doses in dental radiology].

    PubMed

    Bianchi, S D; Roccuzzo, M; Albrito, F; Ragona, R; Anglesio, S

    1996-01-01

    The growing use of dento-maxillo-facial radiographic examinations has been accompanied by the publication of a large number of studies on dosimetry. A thorough review of the literature is presented in this article. Most studies were carried out on tissue equivalent skull phantoms, while only a few were in vivo. The aim of the present study was to evaluate in vivo absorbed doses during Orthopantomography (OPT). Full Mouth Periapical Examination (FMPE) and Intraoral Tube Panoramic Radiography (ITPR). Measurements were made on 30 patients, reproducing clinical conditions, in 46 anatomical sites, with 24 intra- and 22 extra-oral thermoluminiscent dosimeters (TLDS). The highest doses were measured, in orthopantomography, at the right mandibular angle (1899 mu Gy) in FMPE on the right naso-labial fold (5640 mu Gy and in ITPR on the palatal surface of the left second upper molar (1936 mu Gy). Intraoral doses ranged from 21 mu Gy, in orthopantomography, to 4494 mu Gy in FMPE. Standard errors ranged from 142% in ITPR to 5% in orthopantomography. The highest rate of standard errors was found in FMPE and ITPR. The data collected in this trial are in agreement with others in major literature reports. Disagreements are probably due to different exam acquisition and data collections. Such differences, presented comparison in several sites, justify lower doses in FMPE and ITPR. Advantages and disadvantages of in vivo dosimetry of the maxillary region are discussed, the former being a close resemblance to clinical conditions of examination and the latter the impossibility of collecting values in depth of tissues. Finally, both ITPR and FMPE required lower doses than expected, and can be therefore reconsidered relative to their radiation risk.

  14. Pitch fractionation. Technical report

    SciTech Connect

    Weinberg, V.L.; White, J.L.

    1981-12-15

    Petroleum pitch (Ashland A240) has been subjected to thermal treatment and solvent fractionation to produce refined pitches to be evaluated as impregnants for carbon-carbon composites. The solvent fractions were obtained by sequential Soxhlet extraction with solvents such as hexane, cyclohexane, toluene, and pyridine. The most severe thermal treatment produced a mesophase pitch (approximately 50% mesophase); an appreciable portion of the mesophase was soluble in strong solvents. There were substantial differences in chemical composition and in pyrolysis behavior of the fractions. As the depth of fraction increased, the pyrolysis yield and bloating increased, and the microstructure of the coke became finer until glassy microconstituents were formed in the deepest fractions.

  15. The Survivability Analysis Framework (SAF)

    DTIC Science & Technology

    2016-06-13

    identification JTAC provides target corrections to aircrews as needed JTAC clears or aborts aircraft to attack Post-Condition Target is attacked 35...Critical Resource Impact Evaluation Failure impact potential: • High: mission abort , mission errors with fratricide, wrong target • Medium: mission

  16. Noise-induced absorbing phase transition in a model of opinion formation

    NASA Astrophysics Data System (ADS)

    Vieira, Allan R.; Crokidakis, Nuno

    2016-08-01

    In this work we study a 3-state (+1, -1, 0) opinion model in the presence of noise and disorder. We consider pairwise competitive interactions, with a fraction p of those interactions being negative (disorder). Moreover, there is a noise q that represents the probability of an individual spontaneously change his opinion to the neutral state. Our aim is to study how the increase/decrease of the fraction of neutral agents affects the critical behavior of the system and the evolution of opinions. We derive analytical expressions for the order parameter of the model, as well as for the stationary fraction of each opinion, and we show that there are distinct phase transitions. One is the usual ferro-paramagnetic transition, that is in the Ising universality class. In addition, there are para-absorbing and ferro-absorbing transitions, presenting the directed percolation universality class. Our results are complemented by numerical simulations.

  17. Design of a nonlinear torsional vibration absorber

    NASA Astrophysics Data System (ADS)

    Tahir, Ammaar Bin

    Tuned mass dampers (TMD) utilizing linear spring mechanisms to mitigate destructive vibrations are commonly used in practice. A TMD is usually tuned for a specific resonant frequency or an operating frequency of a system. Recently, nonlinear vibration absorbers attracted attention of researchers due to some potential advantages they possess over the TMDs. The nonlinear vibration absorber, or the nonlinear energy sink (NES), has an advantage of being effective over a broad range of excitation frequencies, which makes it more suitable for systems with several resonant frequencies, or for a system with varying excitation frequency. Vibration dissipation mechanism in an NES is passive and ensures that there is no energy backflow to the primary system. In this study, an experimental setup of a rotational system has been designed for validation of the concept of nonlinear torsional vibration absorber with geometrically induced cubic stiffness nonlinearity. Dimensions of the primary system have been optimized so as to get the first natural frequency of the system to be fairly low. This was done in order to excite the dynamic system for torsional vibration response by the available motor. Experiments have been performed to obtain the modal parameters of the system. Based on the obtained modal parameters, the design optimization of the nonlinear torsional vibration absorber was carried out using an equivalent 2-DOF modal model. The optimality criterion was chosen to be maximization of energy dissipation in the nonlinear absorber attached to the equivalent 2-DOF system. The optimized design parameters of the nonlinear absorber were tested on the original 5-DOF system numerically. A comparison was made between the performance of linear and nonlinear absorbers using the numerical models. The comparison showed the superiority of the nonlinear absorber over its linear counterpart for the given set of primary system parameters as the vibration energy dissipation in the former is

  18. Thin film absorber for a solar collector

    DOEpatents

    Wilhelm, William G.

    1985-01-01

    This invention pertains to energy absorbers for solar collectors, and more particularly to high performance thin film absorbers. The solar collectors comprising the absorber of this invention overcome several problems seen in current systems, such as excessive hardware, high cost and unreliability. In the preferred form, the apparatus features a substantially rigid planar frame with a thin film window bonded to one planar side of the frame. An absorber in accordance with the present invention is comprised of two thin film layers that are sealed perimetrically. In a preferred embodiment, thin film layers are formed from a metal/plastic laminate. The layers define a fluid-tight planar envelope of large surface area to volume through which a heat transfer fluid flows. The absorber is bonded to the other planar side of the frame. The thin film construction of the absorber assures substantially full envelope wetting and thus good efficiency. The window and absorber films stress the frame adding to the overall strength of the collector.

  19. Dividing Fractions: A Pedagogical Technique

    ERIC Educational Resources Information Center

    Lewis, Robert

    2016-01-01

    When dividing one fraction by a second fraction, invert, that is, flip the second fraction, then multiply it by the first fraction. To multiply fractions, simply multiply across the denominators, and multiply across the numerators to get the resultant fraction. So by inverting the division of fractions it is turned into an easy multiplication of…

  20. The nonlinear piezoelectric tuned vibration absorber

    NASA Astrophysics Data System (ADS)

    Soltani, P.; Kerschen, G.

    2015-07-01

    This paper proposes a piezoelectric vibration absorber, termed the nonlinear piezoelectric tuned vibration absorber (NPTVA), for the mitigation of nonlinear resonances of mechanical systems. The new feature of the NPTVA is that its nonlinear restoring force is designed according to a principle of similarity, i.e., the NPTVA should be an electrical analog of the nonlinear host system. Analytical formulas for the NPTVA parameters are derived using the homotopy perturbation method. Doing so, a nonlinear generalization of Den Hartog’s equal-peak tuning rule is developed for piezoelectric vibration absorbers.

  1. FRACTIONAL PEARSON DIFFUSIONS.

    PubMed

    Leonenko, Nikolai N; Meerschaert, Mark M; Sikorskii, Alla

    2013-07-15

    Pearson diffusions are governed by diffusion equations with polynomial coefficients. Fractional Pearson diffusions are governed by the corresponding time-fractional diffusion equation. They are useful for modeling sub-diffusive phenomena, caused by particle sticking and trapping. This paper provides explicit strong solutions for fractional Pearson diffusions, using spectral methods. It also presents stochastic solutions, using a non-Markovian inverse stable time change.

  2. FRACTIONAL PEARSON DIFFUSIONS

    PubMed Central

    Leonenko, Nikolai N.; Meerschaert, Mark M.

    2013-01-01

    Pearson diffusions are governed by diffusion equations with polynomial coefficients. Fractional Pearson diffusions are governed by the corresponding time-fractional diffusion equation. They are useful for modeling sub-diffusive phenomena, caused by particle sticking and trapping. This paper provides explicit strong solutions for fractional Pearson diffusions, using spectral methods. It also presents stochastic solutions, using a non-Markovian inverse stable time change. PMID:23626377

  3. Attenuation of external Bremsstrahlung in metallic absorbers

    SciTech Connect

    Dhaliwal, A.S.; Powar, M.S.; Singh, M. )

    1990-12-01

    In this paper attenuation of bremsstrahlung from {sup 147}Pm and {sup 170}Tm beta emitters has been studied in aluminum, copper, tin, and lead metallic absorbers. Bremsstrahlung spectra and mass attenuation coefficients for monoenergetic gamma rays are used to calculate theoretical attenuation curves. Magnetic deflection and beta stopping techniques are used to measure the integral bremsstrahlung intensities above 30 keV in different target thicknesses. Comparison of measured and calculated attenuation curves shows a good agreement for various absorbers, thus providing a test of this technique, which may be useful in understanding bremsstrahlung intensity buildup and in the design of optimum shielding for bremsstrahlung sources. It is found that the absorption of bremsstrahlung in metallic absorbers does not obey an exponential law and that absorbers act as energy filters.

  4. Energy absorber uses expanded coiled tube

    NASA Technical Reports Server (NTRS)

    Johnson, E. F.

    1972-01-01

    Mechanical shock mitigating device, based on working material to its failure point, absorbs mechanical energy by bending or twisting tubing. It functions under axial or tangential loading, has no rebound, is area independent, and is easy and inexpensive to build.

  5. Neutron absorbing coating for nuclear criticality control

    DOEpatents

    Mizia, Ronald E.; Wright, Richard N.; Swank, William D.; Lister, Tedd E.; Pinhero, Patrick J.

    2007-10-23

    A neutron absorbing coating for use on a substrate, and which provides nuclear criticality control is described and which includes a nickel, chromium, molybdenum, and gadolinium alloy having less than about 5% boron, by weight.

  6. Durability of Polymeric Glazing and Absorber Materials

    SciTech Connect

    Jorgensen, G.; Terwilliger, K.; Bingham, C.; Milbourne, M.

    2005-01-01

    The Solar Heating and Lighting Program has set the goal of reducing the cost of solar water heating systems by at least 50%. An attractive approach to such large cost reduction is to replace glass and metal parts with less-expensive, lighter-weight, more-integrated polymeric components. The key challenge with polymers is to maintain performance and assure requisite durability for extended lifetimes. The objective of this task is to quantify lifetimes through measurement of the optical and mechanical stability of candidate polymeric glazing and absorber materials. Polycarbonate sheet glazings, as proposed by two industry partners, have been tested for resistance to UV radiation with three complementary methods. Incorporation of a specific 2-mil thick UV-absorbing screening layer results in glazing lifetimes of at least 15 years; improved screens promise even longer lifetimes. Proposed absorber materials were tested for creep and embrittlement under high temperature, and appear adequate for planned ICS absorbers.

  7. Nonlinear dynamic model for magnetically-tunable Galfenol vibration absorbers

    NASA Astrophysics Data System (ADS)

    Scheidler, Justin J.; Dapino, Marcelo J.

    2013-03-01

    This paper presents a single degree of freedom model for the nonlinear vibration of a metal-matrix composite manufactured by ultrasonic additive manufacturing that contains seamlessly embedded magnetostrictive Galfenol alloys (FeGa). The model is valid under arbitrary stress and magnetic field. Changes in the composite's natural frequency are quantified to assess its performance as a semi-active vibration absorber. The effects of Galfenol volume fraction and location within the composite on natural frequency are quantified. The bandwidth over which the composite's natural frequency can be tuned with a bias magnetic field is studied for varying displacement excitation amplitudes. The natural frequency is tunable for all excitation amplitudes considered, but the maximum tunability occurs below an excitation amplitude threshold of 1 × 10-6 m for the composite geometry considered. Natural frequency shifts between 6% and 50% are found as the Galfenol volume fraction varies from 25% to 100% when Galfenol is located at the composite neutral axis. At a modest 25% Galfenol by volume, the model shows that up to 15% shifts in composite resonance are possible through magnetic bias field modulation if Galfenol is embedded away from the composite midplane. As the Galfenol volume fraction and distance between Galfenol and composite midplane are increased, linear and quadratic increases in tunability result, respectively.

  8. A study of warm absorbers in active galactic nuclei

    NASA Astrophysics Data System (ADS)

    Ashton, Ceri Ellen

    This thesis explores the 'warm absorber' phenomenon observed in Active Galactic Nuclei (AGN). Warm absorbers are clouds of ionised gas within AGN, that cause absorption at soft X-ray wavelengths. They are observed in half of all Type 1 AGN, hence they play an important part in the framework of our under standing of Active Galactic Nuclei. Observations with the satellite XMM-Newton have given us the highest signal-to-noise data yet. XMM-Newton observations of the quasars PG 1114+445 and PG 1309+355 are studied. Both quasars exhibit evidence for absorption by warm material in the line-of-sight. We define a 'phase' of absorption to have a single ionisation param eter and column density. From fits to the data, the absorption in PG 1114+445 is found to be in two phases, a 'hot' phase with a log ionisation parameter f of 2.57 and a column of 1022 cm-2, and a 'cooler' one with log f of 0.83 and a column of 1021 cm-2. The absorption in PG 1309+355 consists of a single phase, with log f of 1.87 and a column of 1021 cm-2. The absorbing gas lies at distances of 1019 - 1022 cm from the continuum radiation sources in these AGN, suggesting origins in a wind emanating from a molecular torus, according to the 'Standard Model' of AGN. The kinetic luminosities of the outflowing absorbers represent insignificant fractions (< 10 3) of the energy budgets of the AGN. Using data for the Seyfert 1 H 0557 385, the warm absorption is characterised by two phases, a phase with log £ of 0.48 and a column of 1021 cm-2, and a phase with log f of 1.63 and a column of 1022 cm-2. Neutral absorption is also present in the source, and possible origins for this are discussed. For a large sample, observations of warm absorbers are collated and compared with models.

  9. Porous absorber for solar air heaters

    SciTech Connect

    Finch, J.A.

    1980-09-10

    A general discussion of the factors affecting solar collector performance is presented. Bench scale tests done to try to determine the heat transfer characteristics of various screen materials are explained. The design, performance, and evaluation of a crude collector with a simple screen stack absorber is treated. The more sophisticated absorber concept, and its first experimental approximation is examined. A short summary of future plans for the collector concept is included. (MHR)

  10. Multilayer Radar Absorbing Non-Woven Material

    NASA Astrophysics Data System (ADS)

    Dedov, A. V.; Nazarov, V. G.

    2016-06-01

    We study the electrical properties of multilayer radar absorbing materials obtained by adding nonwoven sheets of dielectric fibers with an intermediate layer of electrically conductive carbon fibers. Multilayer materials that absorb electromagnetic radiation in a wide frequency range are obtained by varying the content of the carbon fibers. The carbon-fiber content dependent mechanism of absorption of electromagnetic radiation by sheets and multilayer materials is considered.

  11. Non-absorbed Antibiotics for IBS

    DTIC Science & Technology

    2012-03-16

    absorbed antibiotic rifaximin for nonconstipated irritable bowel syndrome (IBS). This effort adds to the body of literature from other, smaller studies that...have demonstrated clinical efficacy for IBS with rifaximin . Non-absorbed antibiotics have been endorsed by the American College of Gastroenterology... rifaximin 400 mg three times daily for 10 days or placebo. During the initial 2 weeks of therapy and the subsequent 10 weeks of follow-up rifaximin

  12. Structured metal film as a perfect absorber.

    PubMed

    Xiong, Xiang; Jiang, Shang-Chi; Hu, Yu-Hui; Peng, Ru-Wen; Wang, Mu

    2013-08-07

    A new type of absorber, a four-tined fish-spear-like resonator (FFR), constructed by the two-photon polymerization process, is reported. An absorbance of more than 90% is experimentally realized and the resonance occurs in the space between the tines. Since a continuous layer of metallic thin film covers the structure, it is perfectly thermo- and electroconductive, which is the mostly desired feature for many applications.

  13. Radar Absorbing Materials for Cube Stealth Satellite

    NASA Astrophysics Data System (ADS)

    Micheli, D.; Pastore, R.; Vricella, A.; Marchetti, M.

    A Cube Stealth Satellite is proposed for potential applications in defense system. Particularly, the faces of the satellite exposed to the Earth are made of nanostructured materials able to absorb radar surveillance electromagnetic waves, conferring stealth capability to the cube satellite. Microwave absorbing and shielding material tiles are proposed using composite materials consisting in epoxy-resin and carbon nanotubes filler. The electric permittivity of the composite nanostructured materials is measured and discussed. Such data are used by the modeling algorithm to design the microwave absorbing and the shielding faces of the cube satellite. The electromagnetic modeling takes into account for several incidence angles (0-80°), extended frequency band (2-18 GHz), and for the minimization of the electromagnetic reflection coefficient. The evolutionary algorithm used for microwave layered microwave absorber modeling is the recently developed Winning Particle Optimization. The mathematical model of the absorbing structure is finally experimentally validated by comparing the electromagnetic simulation to the measurement of the manufactured radar absorber tile. Nanostructured composite materials manufacturing process and electromagnetic reflection measurements methods are described. Finally, a finite element method analysis of the electromagnetic scattering by cube stealth satellite is performed.

  14. Absorbance changes of carotenoids in different solvents.

    PubMed

    Zang, L Y; Sommerburg, O; van Kuijk, F J

    1997-01-01

    Carotenoids are typically measured in tissues with the high performance liquid chromatography (HPLC) and quantitation is usually done by calibrating with stock solutions in solvents. Four carotenoids including lutein, zeaxanthin, lycopene and beta-carotene were dissolved in hexane and methanol respectively, and their absorbance characteristics were compared. Lutein shows absorbance spectra that are almost independent of solvents at various concentrations. Spectra of zeaxanthin, lycopene and beta-carotene were found to be more solvent-dependent. The absorbance of zeaxanthin at lambda max is about approximately 2 times larger in methanol than in hexane at the higher concentrations, and increased non-linearly with increasing concentration in hexane. The absorbance of lycopene at lambda max in hexane is approximately 4 fold larger than in methanol, but the absorbance of the methanol sample can be recovered by re-extracting this sample in hexane. The absorbance of beta-carotene in hexane is larger than in methanol, and increased linearly with increasing concentration. But beta-carotene showed a non-linear concentration effect in methanol. There are very small variations in lambda max for all four carotenoids between hexane and methanol, due to differences in molar extinction coefficients. The non-linear concentration effects for these carotenoids are probably due to differences in solubility leading to the formation of microcrystals. Thus, care should be taken with quantitation of tissue carotenoid values, when they depend on measurement of concentrations in stock solutions.

  15. Perfect terahertz absorber using fishnet based metafilm

    SciTech Connect

    Azad, Abul Kalam; Shchegolkov, Dmitry Yu; Chen, Houtong; Taylor, Antoinette; Smirnova, E I; O' Hara, John F

    2009-01-01

    We present a perfect terahertz (THz) absorber working for a broad-angle of incidence. The two fold symmetry of rectangular fishnet structure allows either complete absorption or mirror like reflection depending on the polarization of incident the THz beam. Metamaterials enable the ability to control the electromagnetic wave in a unique fashion by designing the permittivity or permeability of composite materials with desired values. Although the initial idea of metamaterials was to obtain a negative index medium, however, the evolution of metamaterials (MMs) offers a variety of practically applicable devices for controlling electromagnetic wave such as tunable filters, modulators, phase shifters, compact antenna, absorbers, etc. Terahertz regime, a crucial domain of the electromagnetic wave, is suffering from the scarcity of the efficient devices and might take the advantage of metamaterials. Here, we demonstrate design, fabrication, and characterization of a terahertz absorber based on a simple fishnet metallic film separated from a ground mirror plane by a dielectric spacer. Such absorbers are in particular important for bolometric terahertz detectors, high sensitivity imaging, and terahertz anechoic chambers. Recently, split-ring-resonators (SRR) have been employed for metamaterial-based absorbers at microwave and THz frequencies. The experimental demonstration reveals that such absorbers have absorptivity close to unity at resonance frequencies. However, the downside of these designs is that they all employ resonators of rather complicated shape with many fine parts and so they are not easy to fabricate and are sensitive to distortions.

  16. Meteosat SEVIRI Fire Radiative Power (FRP) products from the Land Surface Analysis Satellite Applications Facility (LSA SAF) - Part 1: Algorithms, product contents and analysis

    NASA Astrophysics Data System (ADS)

    Wooster, M. J.; Roberts, G.; Freeborn, P. H.; Xu, W.; Govaerts, Y.; Beeby, R.; He, J.; Lattanzio, A.; Mullen, R.

    2015-06-01

    Characterising changes in landscape scale fire activity at very high temporal resolution is best achieved using thermal observations of actively burning fires made from geostationary Earth observation (EO) satellites. Over the last decade or more, a series of research and/or operational "active fire" products have been developed from these types of geostationary observations, often with the aim of supporting the generation of data related to biomass burning fuel consumption and trace gas and aerosol emission fields. The Fire Radiative Power (FRP) products generated by the Land Surface Analysis Satellite Applications Facility (LSA SAF) from data collected by the Meteosat Second Generation (MSG) Spinning Enhanced Visible and Infrared Imager (SEVIRI) are one such set of products, and are freely available in both near real-time and archived form. Every 15 min, the algorithms used to generate these products identify and map the location of new SEVIRI observations containing actively burning fires, and characterise their individual rates of radiative energy release (fire radiative power; FRP) that is believed proportional to rates of biomass consumption and smoke emission. The FRP-PIXEL product contains the highest spatial resolution FRP dataset, delivered for all of Europe, northern and southern Africa, and part of South America at a spatial resolution of 3 km (decreasing away from the west African sub-satellite point) at the full 15 min temporal resolution. The FRP-GRID product is an hourly summary of the FRP-PIXEL data, produced at a 5° grid cell size and including simple bias adjustments for meteorological cloud cover and for the regional underestimation of FRP caused, primarily, by the non-detection of low FRP fire pixels at SEVIRI's relatively coarse pixel size. Here we describe the enhanced geostationary Fire Thermal Anomaly (FTA) algorithm used to detect the SEVIRI active fire pixels, and detail methods used to deliver atmospherically corrected FRP information

  17. Can Kindergartners Do Fractions?

    ERIC Educational Resources Information Center

    Cwikla, Julie

    2014-01-01

    Mathematics professor Julie Cwikla decided that she needed to investigate young children's understandings and see what precurricular partitioning notions young minds bring to the fraction table. Cwikla realized that only a handful of studies have examined how preschool-age and early elementary school-age students solve fraction problems (Empson…

  18. An Appetite for Fractions

    ERIC Educational Resources Information Center

    Wilkerson, Trena L.; Bryan, Tommy; Curry, Jane

    2012-01-01

    This article describes how using candy bars as models gives sixth-grade students a taste for learning to represent fractions whose denominators are factors of twelve. Using paper models of the candy bars, students explored and compared fractions. They noticed fewer different representations for one-third than for one-half. The authors conclude…

  19. On fractional programming

    SciTech Connect

    Bajona-Xandri, C.; Martinez-Legaz, J.E.

    1994-12-31

    This paper studies the minimax fractional programming problem, assuming quasiconvexity of the objective function, under the lower subdifferentiability viewpoint. Necessary and sufficient optimality conditions and dual properties are found. We present applications of this theory to find the Pareto efficient solutions of a multiobjective fractional problem and to solve several economic models.

  20. (Carbon isotope fractionation inplants)

    SciTech Connect

    O'Leary, M.H.

    1990-01-01

    The objectives of this research are: To develop a theoretical and experimental framework for understanding isotope fractionations in plants; and to develop methods for using this isotope fractionation for understanding the dynamics of CO{sub 2} fixation in plants. Progress is described.

  1. Fractional dissipative standard map.

    PubMed

    Tarasov, Vasily E; Edelman, M

    2010-06-01

    Using kicked differential equations of motion with derivatives of noninteger orders, we obtain generalizations of the dissipative standard map. The main property of these generalized maps, which are called fractional maps, is long-term memory. The memory effect in the fractional maps means that their present state of evolution depends on all past states with special forms of weights. Already a small deviation of the order of derivative from the integer value corresponding to the regular dissipative standard map (small memory effects) leads to the qualitatively new behavior of the corresponding attractors. The fractional dissipative standard maps are used to demonstrate a new type of fractional attractors in the wide range of the fractional orders of derivatives.

  2. Optical Properties and Aging of Light Absorbing Secondary Organic Aerosol

    SciTech Connect

    Liu, Jiumeng; Lin, Peng; Laskin, Alexander; Laskin, Julia; Kathmann, Shawn M.; Wise, Matthew E.; Caylor, Ryan; Imholt, Felisha; Selimovic, Vanessa; Shilling, John E.

    2016-10-14

    The light-absorbing organic aerosol (OA), commonly referred to as “brown carbon (BrC)”, has attracted considerable attention in recent years because of its potential to affect atmospheric radiation balance, especially in the ultraviolet region and thus impact photochemical processes. A growing amount of data has indicated that BrC is prevalent in the atmosphere, which has motivated numerous laboratory and field studies; however, our understanding of the relationship between the chemical composition and optical properties of BrC remains limited. We conducted chamber experiments to investigate the effect of various VOC precursors, NOx concentrations, photolysis time and relative humidity (RH) on the light absorption of selected secondary organic aerosols (SOA). Light absorption of chamber generated SOA samples, especially aromatic SOA, was found to increase with NOx concentration, at moderate RH, and for the shortest photolysis aging times. The highest mass absorption coefficients (MAC) value is observed from toluene SOA products formed under high NOx conditions at moderate RH, in which nitro-aromatics were previously identified as the major light absorbing compounds. BrC light absorption is observed to decrease with photolysis time, correlated with a decline of the organonitrate fraction of SOA. SOA formed from mixtures of aromatics and isoprene absorb less visible and UV light than SOA formed from aromatic precursors alone on a mass basis. However, the mixed-SOA absorption was underestimated when optical properties were predicted using a two-product SOA formation model, as done in many current climate models. Further investigation, including analysis on detailed mechanisms, are required to explain the discrepancy.

  3. Glory on Venus cloud tops and the unknown UV absorber

    NASA Astrophysics Data System (ADS)

    Markiewicz, W. J.; Petrova, E.; Shalygina, O.; Almeida, M.; Titov, D. V.; Limaye, S. S.; Ignatiev, N.; Roatsch, T.; Matz, K. D.

    2014-05-01

    We report on the implications of the observations of the glory phenomenon made recently by Venus Express orbiter. Glory is an optical phenomenon that poses stringent constraints on the cloud properties. These observations thus enable us to constrain two properties of the particles at the cloud tops (about 70 km altitude) which are responsible for a large fraction of the solar energy absorbed by Venus. Firstly we obtain a very accurate estimate of the cloud particles size to be 1.2 μm with a very narrow size distribution. We also find that for the two observations presented here the clouds are homogenous, as far as cloud particles sizes are concerned, on scale of at least 1200 km. This is in contrast to previous estimates that were either local, from entry probes data, or averaged over space and time from polarization data. Secondly we find that the refractive index for the data discussed here is higher than that of sulfuric acid previously proposed for the clouds composition (Hansen, J.E., Hovenier, J.W. [1974]. J. Atmos. Sci. 31, 1137-1160; Ragent, B. et al. [1985]. Adv. Space Res. 5, 85-115). Assuming that the species contributing to the increase of the refractive index is the same as the unknown UV absorber, we are able to constrain the list of candidates. We investigated several possibilities and argue that either small ferric chloride (FeCl3) cores inside sulfuric acid particles or elemental sulfur coating their surface are good explanations of the observation. Both ferric chloride and elemental sulfur have been suggested in the past as candidates for the as yet unknown UV absorber (Krasnopolsky, V.A. [2006]. Planet. Space Sci. 54, 1352-1359; Mills, F.P. et al. [2007]. In: Esposito, L.W., Stofan, E.R., Cravens, T.E. (Eds.), Exploring Venus as a Terrestrial Planet, vol. 176. AGU Monogr. Ser., Washington, DC, pp. 73-100).

  4. Method of absorbance correction in a spectroscopic heating value sensor

    SciTech Connect

    Saveliev, Alexei; Jangale, Vilas Vyankatrao; Zelepouga, Sergeui; Pratapas, John

    2013-09-17

    A method and apparatus for absorbance correction in a spectroscopic heating value sensor in which a reference light intensity measurement is made on a non-absorbing reference fluid, a light intensity measurement is made on a sample fluid, and a measured light absorbance of the sample fluid is determined. A corrective light intensity measurement at a non-absorbing wavelength of the sample fluid is made on the sample fluid from which an absorbance correction factor is determined. The absorbance correction factor is then applied to the measured light absorbance of the sample fluid to arrive at a true or accurate absorbance for the sample fluid.

  5. Warm Absorber Diagnostics of AGN Dynamics

    NASA Astrophysics Data System (ADS)

    Kallman, Timothy

    Warm absorbers and related phenomena are observable manifestations of outflows or winds from active galactic nuclei (AGN) that have great potential value. Understanding AGN outflows is important for explaining the mass budgets of the central accreting black hole, and also for understanding feedback and the apparent co-evolution of black holes and their host galaxies. In the X-ray band warm absorbers are observed as photoelectric absorption and resonance line scattering features in the 0.5-10 keV energy band; the UV band also shows resonance line absorption. Warm absorbers are common in low luminosity AGN and they have been extensively studied observationally. They may play an important role in AGN feedback, regulating the net accretion onto the black hole and providing mechanical energy to the surroundings. However, fundamental properties of the warm absorbers are not known: What is the mechanism which drives the outflow?; what is the gas density in the flow and the geometrical distribution of the outflow?; what is the explanation for the apparent relation between warm absorbers and the surprising quasi-relativistic 'ultrafast outflows' (UFOs)? We propose a focused set of model calculations that are aimed at synthesizing observable properties of warm absorber flows and associated quantities. These will be used to explore various scenarios for warm absorber dynamics in order to answer the questions in the previous paragraph. The guiding principle will be to examine as wide a range as possible of warm absorber driving mechanisms, geometry and other properties, but with as careful consideration as possible to physical consistency. We will build on our previous work, which was a systematic campaign for testing important class of scenarios for driving the outflows. We have developed a set of tools that are unique and well suited for dynamical calculations including radiation in this context. We also have state-of-the-art tools for generating synthetic spectra, which are

  6. Fractional calculus in bioengineering.

    PubMed

    Magin, Richard L

    2004-01-01

    Fractional calculus (integral and differential operations of noninteger order) is not often used to model biological systems. Although the basic mathematical ideas were developed long ago by the mathematicians Leibniz (1695), Liouville (1834), Riemann (1892), and others and brought to the attention of the engineering world by Oliver Heaviside in the 1890s, it was not until 1974 that the first book on the topic was published by Oldham and Spanier. Recent monographs and symposia proceedings have highlighted the application of fractional calculus in physics, continuum mechanics, signal processing, and electromagnetics, but with few examples of applications in bioengineering. This is surprising because the methods of fractional calculus, when defined as a Laplace or Fourier convolution product, are suitable for solving many problems in biomedical research. For example, early studies by Cole (1933) and Hodgkin (1946) of the electrical properties of nerve cell membranes and the propagation of electrical signals are well characterized by differential equations of fractional order. The solution involves a generalization of the exponential function to the Mittag-Leffler function, which provides a better fit to the observed cell membrane data. A parallel application of fractional derivatives to viscoelastic materials establishes, in a natural way, hereditary integrals and the power law (Nutting/Scott Blair) stress-strain relationship for modeling biomaterials. In this review, I will introduce the idea of fractional operations by following the original approach of Heaviside, demonstrate the basic operations of fractional calculus on well-behaved functions (step, ramp, pulse, sinusoid) of engineering interest, and give specific examples from electrochemistry, physics, bioengineering, and biophysics. The fractional derivative accurately describes natural phenomena that occur in such common engineering problems as heat transfer, electrode/electrolyte behavior, and sub

  7. Water absorbency by wool fibers: Hofmeister effect.

    PubMed

    Lo Nostro, Pierandrea; Fratoni, Laura; Ninham, Barry W; Baglioni, Piero

    2002-01-01

    Wool is a complex material, composed of cuticle and epicuticle cells, surrounded by a cell membrane complex. Wool fibers absorb moisture from air, and, once immersed in water, they take up considerable amounts of liquid. The water absorbency parameter can be determined from weight gain, according to a standard method, and used to quantify this phenomenon. In this paper we report a study on the water absorbency (or retention) of untreated wool fibers in the presence of aqueous 1 M salt solutions at 29 degrees C and a relative humidity of either 33% or 56%. The effect of anions was determined by selecting a wide range of different sodium salts, while the effect of cations was checked through some chlorides and nitrates. Our results show a significant specific ion and ion pair "Hofmeister" effects, that change the amount of water absorbed by the fibers. To understand this phenomenon, the water absorbency parameter (A(w)) is compared to different physicochemical parameters such as the lyotropic number, free energy of hydration of ions, molar surface tension increment, polarizability, refractive index increment, and molar refractivity. The data indicate that this Hofmeister phenomenon is controlled by dispersion forces that depend on the polarizability of ionic species, their adsorption frequencies, the solvent, and the substrate. These dispersion forces dominate the behavior in concentrated solutions. They are in accord with new developing theories of solutions and molecular interactions in colloidal systems that account for Hofmeister effects.

  8. Oxygen absorbers in food preservation: a review.

    PubMed

    Cichello, Simon Angelo

    2015-04-01

    The preservation of packaged food against oxidative degradation is essential to establish and improve food shelf life, customer acceptability, and increase food security. Oxygen absorbers have an important role in the removal of dissolved oxygen, preserving the colour, texture and aroma of different food products, and importantly inhibition of food spoilage microbes. Active packaging technology in food preservation has improved over decades mostly due to the sealing of foods in oxygen impermeable package material and the quality of oxygen absorber. Ferrous iron oxides are the most reliable and commonly used oxygen absorbers within the food industry. Oxygen absorbers have been transformed from sachets of dried iron-powder to simple self-adhesive patches to accommodate any custom size, capacity and application. Oxygen concentration can be effectively lowered to 100 ppm, with applications spanning a wide range of food products and beverages across the world (i.e. bread, meat, fish, fruit, and cheese). Newer molecules that preserve packaged food materials from all forms of degradation are being developed, however oxygen absorbers remain a staple product for the preservation of food and pharmaceutical products to reduce food wastage in developed nations and increased food security in the developing & third world.

  9. Non-Absorbable Gas Behavior in the Absorber/Evaporator of a Absorption Chiller

    NASA Astrophysics Data System (ADS)

    Suzuki, Hiroshi; Nagamoto, Wataru; Sugiyama, Takahide

    A two-dimensional numerical study on non-absorbable gas behavior in the absorber/evaporator of an absorption chiller has been performed. In the present study, the effect of the pitch-to-diameter ratio of a cylinder bundle in the absorber was highlighted. From the results, a sudden decrease of the overall heat transfer coefficient of the absorber was observed at a certain mean concentration of non-absorbable gas for each pitch-to-diameter ratio. Such a critical concentration was also found to decrease as the pitch-to- diameter ratio increased. The sudden decrease occurs due to the sudden disappearance of recirculating region, which is formed between the absorber and the evaporator, and where most of non-absorbable gas stays when it exists. As the pitch-to-diameter ratio increases, the recirculating region becomes weak because the velocity of the high velocity region supporting the recirculating flow decreases. Then, the critical mean concentration of non-absorbable gas is found to decrease as pitch-to-ratio increases.

  10. Optical analysis of solar energy tubular absorbers.

    PubMed

    Saltiel, C; Sokolov, M

    1982-11-15

    The energy absorbed by a solar energy tubular receiver element for a single incident ray is derived. Two types of receiver elements were analyzed: (1) an inner tube with an absorbing coating surrounded by a semitransparent cover tube, and (2) a semitransparent inner tube filled with an absorbing fluid surrounded by a semitransparent cover tube. The formation of ray cascades in the semitransparent tubes is considered. A numerical simulation to investigate the influence of the angle of incidence, sizing, thickness, and coefficient of extinction of the tubes was performed. A comparison was made between receiver elements with and without cover tubes. Ray tracing analyses in which rays were followed within the tubular receiver element as well as throughout the rest of the collector were performed for parabolic and circular trough concentrating collectors.

  11. Interference theory of metamaterial perfect absorbers.

    PubMed

    Chen, Hou-Tong

    2012-03-26

    The impedance matching to free space in metamaterial perfect absorbers has been believed to involve and rely on magnetic resonant response, with direct evidence provided by the anti-parallel surface currents in the metal structures. Here I present a different theoretical interpretation based on interference, which shows that the two layers of metal structures in metamaterial absorbers are linked only by multiple reflections with negligible near-field interactions or magnetic resonances. This is further supported by the out-of-phase surface currents derived at the interfaces of resonator array and ground plane through multiple reflections and superpositions. The theory developed here explains all features observed in narrowband metamaterial absorbers and therefore provides a profound understanding of the underlying physics.

  12. Translatory shock absorber for attitude sensors

    NASA Technical Reports Server (NTRS)

    Vonpragenau, G. L.; Morgan, I. T., Jr.; Kirby, C. A. (Inventor)

    1976-01-01

    A translatory shock absorber is provided for mounting an attitude sensor thereon for isolating a sensor from translatory vibrations. The translatory shock absorber includes a hollow block structure formed as one piece to form a parallelogram. The absorber block structure includes a movable top plate for supporting the attitude sensor and a fixed base plate with opposed side plates interposed between. At the junctions of the side plates, and the base and top plates, there are provided grooves which act as flexible hinges for attenuating translatory vibrations. A damping material is supported on a pedestal which is carried on the base plate between the side plates thereof. The top of the damping material rests against the bottom surface of the top plate for eliminating the resonant peaks of vibration.

  13. Absorber Materials at Room and Cryogenic Temperatures

    SciTech Connect

    F. Marhauser, T.S. Elliott, A.T. Wu, E.P. Chojnacki, E. Savrun

    2011-09-01

    We recently reported on investigations of RF absorber materials at cryogenic temperatures conducted at Jefferson Laboratory (JLab). The work was initiated to find a replacement material for the 2 Kelvin low power waveguide Higher Order Mode (HOM) absorbers employed within the original cavity cryomodules of the Continuous Electron Beam Accelerator Facility (CEBAF). This effort eventually led to suitable candidates as reported in this paper. Furthermore, though constrained by small funds for labor and resources, we have analyzed a variety of lossy ceramic materials, several of which could be usable as HOM absorbers for both normal conducting and superconducting RF structures, e.g. as loads in cavity waveguides and beam tubes either at room or cryogenic temperatures and, depending on cooling measures, low to high operational power levels.

  14. Ferrite HOM Absorber for the RHIC ERL

    SciTech Connect

    Hahn,H.; Choi, E.M.; Hammons, L.

    2008-10-01

    A superconducting Energy Recovery Linac is under construction at Brookhaven National Laboratory to serve as test bed for RHIC upgrades. The damping of higher-order modes in the superconducting five-cell cavity for the Energy-Recovery linac at RHIC is performed exclusively by two ferrite absorbers. The ferrite properties have been measured in ferrite-loaded pill box cavities resulting in the permeability values given by a first-order Debye model for the tiled absorber structure and an equivalent permeability value for computer simulations with solid ring dampers. Measured and simulated results for the higher-order modes in the prototype copper cavity are discussed. First room-temperature measurements of the finished niobium cavity are presented which confirm the effective damping of higher-order modes in the ERL. by the ferrite absorbers.

  15. Fractional market dynamics

    NASA Astrophysics Data System (ADS)

    Laskin, Nick

    2000-12-01

    A new extension of a fractality concept in financial mathematics has been developed. We have introduced a new fractional Langevin-type stochastic differential equation that differs from the standard Langevin equation: (i) by replacing the first-order derivative with respect to time by the fractional derivative of order μ; and (ii) by replacing “white noise” Gaussian stochastic force by the generalized “shot noise”, each pulse of which has a random amplitude with the α-stable Lévy distribution. As an application of the developed fractional non-Gaussian dynamical approach the expression for the probability distribution function (pdf) of the returns has been established. It is shown that the obtained fractional pdf fits well the central part and the tails of the empirical distribution of S&P 500 returns.

  16. Catalytic reforming of naphtha fractions

    SciTech Connect

    Bishop, K.C.; Vorhis, F.H.

    1980-09-16

    Production of motor gasoline and a btx-enriched reformate by fractionating a naphtha feedstock into a mid-boiling btxprecursor fraction, a relatively high-boiling fraction and a relatively low-boiling fraction; catalytically reforming the btxprecursor fraction in a first reforming zone; combining the relatively high-boiling and low-boiling fractions and catalytically reforming the combined fractions in a second reforming zone.

  17. Optimization and engineering of microwave absorbers

    NASA Astrophysics Data System (ADS)

    Chen, Kuo-Liang

    1998-12-01

    In this thesis, a concerted effort has been made to study and evaluate the individual electromagnetic properties of the absorbing components including carbon black, conducting fibers, metal flakes, magnetic materials such as carbonyl iron, ferrite and the chiral type of micro- carbon coil. The study of the electromagnetic properties covers functions such as dielectric dissipation, random scattering effect at low and high frequencies, magnetic dissipation at high frequencies and also the effect of chirality for different angles of incidence. The results of these studies have been used in the design, engineering and optimization of the microwave absorbers. The objective of this thesis is to identify the absorption mechanism of each of various type of fillers and to study the synergic effect arising from a combination of these in a non-metallic host medium. This will help us in producing microwave absorbers suitable for broad band application with the advantages of light weight, having high strength and possessing good chemical resistance. The results from experimental measurements of various material combinations have been greatly influenced by the theoretical understanding of the absorption mechanism. Design of microwave absorbers is governed by the requirement of the users as well as the characteristics of the objects (targets) inferred by theoretical understanding and experimental data to arrive at the right formula. Finally a detailed quality control program has to be charted out reflecting both the electromagnetic as well as mechanical properties. This is done by carrying out the tests systematically on small samples and then proceeding to practical absorbers making use of the data compiled earlier on smaller samples. In this thesis, to modify all dielectric absorbing components including micro-carbon chirals to reduce the sensitivity of absorption for different incident angles is unprecedented topic.

  18. Absorber topography dependence of phase edge effects

    NASA Astrophysics Data System (ADS)

    Shanker, Aamod; Sczyrba, Martin; Connolly, Brid; Waller, Laura; Neureuther, Andy

    2015-10-01

    Mask topography contributes to phase at the wafer plane, even for OMOG binary masks currently in use at the 22nm node in deep UV (193nm) lithography. Here, numerical experiments with rigorous FDTD simulation are used to study the impact of mask 3D effects on aerial imaging, by varying the height of the absorber stack and its sidewall angle. Using a thin mask boundary layer model to fit to rigorous simulations it is seen that increasing the absorber thickness, and hence the phase through the middle of a feature (bulk phase) monotonically changes the wafer-plane phase. Absorber height also influences best focus, revealed by an up/down shift in the Bossung plot (linewidth vs. defocus). Bossung plot tilt, however, responsible for process window variability at the wafer, is insensitive to changes in the absorber height (and hence also the bulk phase). It is seen to depend instead on EM edge diffraction from the thick mask edge (edge phase), but stays constant for variations in mask thickness within a 10% range. Both bulk phase and edge phase are also independent of sidewall angle fluctuation, which is seen to linearly affect the CD at the wafer, but does not alter wafer phase or the defocus process window. Notably, as mask topography varies, the effect of edge phase can be replicated by a thin mask model with 8nm wide boundary layers, irrespective of absorber height or sidewall angle. The conclusions are validated with measurements on phase shifting masks having different topographic parameters, confirming the strong dependence of phase variations at the wafer on bulk phase of the mask absorber.

  19. Intracellular Cadmium Isotope Fractionation

    NASA Astrophysics Data System (ADS)

    Horner, T. J.; Lee, R. B.; Henderson, G. M.; Rickaby, R. E.

    2011-12-01

    Recent stable isotope studies into the biological utilization of transition metals (e.g. Cu, Fe, Zn, Cd) suggest several stepwise cellular processes can fractionate isotopes in both culture and nature. However, the determination of fractionation factors is often unsatisfactory, as significant variability can exist - even between different organisms with the same cellular functions. Thus, it has not been possible to adequately understand the source and mechanisms of metal isotopic fractionation. In order to address this problem, we investigated the biological fractionation of Cd isotopes within genetically-modified bacteria (E. coli). There is currently only one known biological use or requirement of Cd, a Cd/Zn carbonic anhydrase (CdCA, from the marine diatom T. weissfloggii), which we introduce into the E. coli genome. We have also developed a cleaning procedure that allows for the treating of bacteria so as to study the isotopic composition of different cellular components. We find that whole cells always exhibit a preference for uptake of the lighter isotopes of Cd. Notably, whole cells appear to have a similar Cd isotopic composition regardless of the expression of CdCA within the E. coli. However, isotopic fractionation can occur within the genetically modified E. coli during Cd use, such that Cd bound in CdCA can display a distinct isotopic composition compared to the cell as a whole. Thus, the externally observed fractionation is independent of the internal uses of Cd, with the largest Cd isotope fractionation occurring during cross-membrane transport. A general implication of these experiments is that trace metal isotopic fractionation most likely reflects metal transport into biological cells (either actively or passively), rather than relating to expression of specific physiological function and genetic expression of different metalloenzymes.

  20. Thermodynamics in Fractional Calculus

    NASA Astrophysics Data System (ADS)

    Meilanov, R. P.; Magomedov, R. A.

    2014-11-01

    A generalization of thermodynamics in the formalism of fractional-order derivatives is given. Results of the traditional thermodynamics of Carnot, Clausius, and Helmholtz are obtained in the particular case where the exponent of a fractional-order derivative is equal to unity. A one-parametric "fractal" equation of state is obtained with account of the second virial coefficient. The application of the resulting equation of state in the case of the gas argon is considered.

  1. Symmetric continued fractions

    SciTech Connect

    Panprasitwech, Oranit; Laohakosol, Vichian; Chaichana, Tuangrat

    2010-11-11

    Explicit formulae for continued fractions with symmetric patterns in their partial quotients are constructed in the field of formal power series. Similar to the work of Cohn in 1996, which generalized the so-called folding lemma to {kappa}-fold symmetry, the notion of {kappa}-duplicating symmetric continued fractions is investigated using a modification of the 1995 technique due to Clemens, Merrill and Roeder.

  2. Interpretation of FRESCO cloud retrievals in case of absorbing aerosol events

    NASA Astrophysics Data System (ADS)

    Wang, P.; Tuinder, O. N. E.; Tilstra, L. G.; de Graaf, M.; Stammes, P.

    2012-10-01

    Cloud and aerosol information is needed in trace gas retrievals from satellite measurements. The Fast REtrieval Scheme for Clouds from the Oxygen A band (FRESCO) cloud algorithm employs reflectance spectra of the O2 A band around 760 nm to derive cloud pressure and effective cloud fraction. In general, clouds contribute more to the O2 A band reflectance than aerosols. Therefore, the FRESCO algorithm does not correct for aerosol effects in the retrievals and attributes the retrieved cloud information entirely to the presence of clouds, and not to aerosols. For events with high aerosol loading, aerosols may have a dominant effect, especially for almost cloud free scenes. We have analysed FRESCO cloud data and Absorbing Aerosol Index (AAI) data from the Global Ozone Monitoring Experiment (GOME-2) instrument on the Metop-A satellite for events with typical absorbing aerosol types, such as volcanic ash, desert dust and smoke. We find that the FRESCO effective cloud fractions are correlated with the AAI data for these absorbing aerosol events and that the FRESCO cloud pressure contains information on aerosol layer pressure. For cloud free scenes, the derived FRESCO cloud pressure is close to the aerosol layer pressure, especially for optically thick aerosol layers. For cloudy scenes, if the strongly absorbing aerosols are located above the clouds, then the retrieved FRESCO cloud pressure may represent the height of the aerosol layer rather than the height of the clouds. Combining FRESCO and AAI data, an estimate for the aerosol layer pressure can be given.

  3. Chromatographic methods of fractionation.

    PubMed

    Friesen, A D

    1987-01-01

    Chromatography's functional versatility, separation efficiency, gentle non-denaturing separating process and ease of automation and scale-up make it attractive for industrial scale protein purification. The Winnipeg Rh Institute's new Plasma Fractionation facility is an example of the use of chromatography for the large scale purification of plasma protein fractions. The fractionation facility has a capacity to process 800 litres of plasma per batch into blood clotting factor VIII and IX, albumin and intravenous immune serum globulin (i.v. ISG). Albumin and i.v. ISG are purified using ion exchange columns of DEAE-Sepharose (230 litre size), DEAE-Biogel (150 litre size) and CM-Sepharose (150 litre size). The chromatographic process is automated using a Modicon 584 Programmable Logic Controller to regulate valves, pumps and sensors which control plasma flow during fractionation. The stainless steel tanks and piping are automatically cleaned-in-place. The high degree of automation and cleaning provides efficient operation and sanitary processing. Chromatographic methods (DEAE-Sepharose and metal chelation) are also being used at the pilot scale to purify the human blood products superoxide dismutase and hemoglobin from outdated red blood cells. Characterization of the protein fractions produced by chromatography has shown them to be of equal or higher quality than fractions produced by other techniques.

  4. Fractional laser skin resurfacing.

    PubMed

    Alexiades-Armenakas, Macrene R; Dover, Jeffrey S; Arndt, Kenneth A

    2012-11-01

    Laser skin resurfacing (LSR) has evolved over the past 2 decades from traditional ablative to fractional nonablative and fractional ablative resurfacing. Traditional ablative LSR was highly effective in reducing rhytides, photoaging, and acne scarring but was associated with significant side effects and complications. In contrast, nonablative LSR was very safe but failed to deliver consistent clinical improvement. Fractional LSR has achieved the middle ground; it combined the efficacy of traditional LSR with the safety of nonablative modalities. The first fractional laser was a nonablative erbium-doped yttrium aluminum garnet (Er:YAG) laser that produced microscopic columns of thermal injury in the epidermis and upper dermis. Heralding an entirely new concept of laser energy delivery, it delivered the laser beam in microarrays. It resulted in microscopic columns of treated tissue and intervening areas of untreated skin, which yielded rapid reepithelialization. Fractional delivery was quickly applied to ablative wavelengths such as carbon dioxide, Er:YAG, and yttrium scandium gallium garnet (2,790 nm), providing more significant clinical outcomes. Adjustable laser parameters, including power, pitch, dwell time, and spot density, allowed for precise determination of percent surface area, affected penetration depth, and clinical recovery time and efficacy. Fractional LSR has been a significant advance to the laser field, striking the balance between safety and efficacy.

  5. Quantum walk with one variable absorbing boundary

    NASA Astrophysics Data System (ADS)

    Wang, Feiran; Zhang, Pei; Wang, Yunlong; Liu, Ruifeng; Gao, Hong; Li, Fuli

    2017-01-01

    Quantum walks constitute a promising ingredient in the research on quantum algorithms; consequently, exploring different types of quantum walks is of great significance for quantum information and quantum computation. In this study, we investigate the progress of quantum walks with a variable absorbing boundary and provide an analytical solution for the escape probability (the probability of a walker that is not absorbed by the boundary). We simulate the behavior of escape probability under different conditions, including the reflection coefficient, boundary location, and initial state. Moreover, it is also meaningful to extend our research to the situation of continuous-time and high-dimensional quantum walks.

  6. OSCEE fan exhaust bulk absorber treatment evaluation

    NASA Technical Reports Server (NTRS)

    Bloomer, H. E.; Samanich, N. E.

    1980-01-01

    The acoustic suppression capability of bulk absorber material designed for use in the fan exhaust duct walls of the quiet clean short haul experiment engine (OCSEE UTW) was evaluated. The acoustic suppression to the original design for the engine fan duct which consisted of phased single degree-of-freedom wall treatment was tested with a splitter and also with the splitter removed. Peak suppression was about as predicted with the bulk absorber configuration, however, the broadband characteristics were not attained. Post test inspection revealed surface oil contamination on the bulk material which could have caused the loss in bandwidth suppression.

  7. Analysis of Energy-Absorbing Foundations.

    DTIC Science & Technology

    1978-12-15

    1ENN51YVAN&A 5TATL UNIV UNIVERSITY PARK DEPT OF ENGI-CYTC F/S 13/h ANALYSIS OF ENERGY -ABSORBING POUNDATIONS.(U) ECC 78 V H NEUBERT, S Ji YIN DNA01-78...C-0036 UNCLASSIFIED DNA-48OFP NL "M~ENOMOEE MIflfl END ______ 1 32 112.2 MICROCOPY RILSOLUTION TEST CHIART LELL ,NA 480 MIL ANALYSIS OF ENERGY ...8217 REPORT & PERIOD COVERED Final Report for Period ANALYSIS OF ENERGY -ABSORBING FOUNDATIONS I Dee 77-1S Dee 78 6. PERFORMING ORG, REPORT NUMBER 7AUTHOR

  8. Shock-Absorbent Ball-Screw Mechanism

    NASA Technical Reports Server (NTRS)

    Hirr, Otto A., Jr.; Meneely, R. W.

    1986-01-01

    Actuator containing two ball screws in series employs Belleville springs to reduce impact loads, thereby increasing life expectancy. New application of springs increases reliability of equipment in which ball screws commonly used. Set of three springs within lower screw of ball-screw mechanism absorbs impacts that result when parts reach their upper and lower limits of movement. Mechanism designed with Belleville springs as shock-absorbing elements because springs have good energy-to-volume ratio and easily stacked to attain any stiffness and travel.

  9. Radio-Absorbing Nanocoatings on Corrugated Surfaces

    NASA Astrophysics Data System (ADS)

    Antipov, V. B.; Potekaev, A. I.; Vorozhtsov, A. B.; Melentyev, S. V.; Tsyganok, Yu. I.

    2016-12-01

    The feasibility of producing protective radio-absorbing shielding materials on the basis of differently shaped surfaces with nanostructured coatings is investigated. Combinations of special nanostructured materials and technical solutions for the shape of the absorbing surface were tested, in order to create efficient nanocoatings. It is shown that the coatings of interest that meet the requirements of low reflection and high attenuation of transmitted radiation combined with low coating thickness can be developed, using corrugated surfaces. Corrugated chicken egg-packing cell samples with nanostructured carbon coatings were examined and found to allow for effective shielding of electromagnetic radiation and to exhibit minimum reflection coefficients as compared to construction materials.

  10. Timing the warm absorber in NGC 4051

    NASA Astrophysics Data System (ADS)

    Silva, C. V.; Uttley, P.; Costantini, E.

    2016-12-01

    We investigated, using spectral-timing analysis, the characterization of highly ionized outflows in Seyfert galaxies, the so-called warm absorbers. Here, we present our results of the extensive 600 ks of XMM-Newton archival observations of the bright and highly variable Seyfert 1 galaxy NGC 4051 whose spectrum has revealed a complex multicomponent wind. Making use of both RGS and EPIC-pn data, we performed a detailed analysis through a time-dependent photoionization code in combination with spectral and Fourier spectral-timing techniques. The source light curves and the warm absorber parameters obtained from the data were used to simulate the response of the gas to variations in the ionizing flux of the central source. The resulting time variable spectra were employed to predict the effects of the warm absorber on the time lags and coherence of the energy dependent light curves. We have found that, in the absence of any other lag mechanisms, a warm absorber with the characteristics of the one observed in NGC 4051, is able to produce soft lags, up to 100 s, on timescales of hours. The time delay is associated with the response of the gas to changes in the ionizing source, either by photoionization or radiative recombination, which is dependent on its density. The range of radial distances that, under our assumptions, yield longer time delays are distances r 0.3-1.0 × 1016 cm, and hence gas densities n 0.4-3.0 × 107 cm-3. Since these ranges are comparable to the existing estimates of the location of the warm absorber in NGC 4051, we suggest that it is likely that the observed X-ray time lags may carry a signature of the warm absorber response time to changes in the ionizing continuum. Our results show that the warm absorber in NGC 4051 does not introduce lags on the short timescales associated with reverberation, but will likely modify the hard continuum lags seen on longer timescales, which in this source have been measured to be on the order of 50 s. Hence, these

  11. Durability of Polymeric Glazing and Absorber Materials

    SciTech Connect

    Jorgensen, G.; Terwilliger, K.; Bingham, C.; Lindquist, C.; Milbourne, M.

    2005-11-01

    The Solar Heating and Lighting Program has set the goal of reducing the cost of solar water heating systems by at least 50%. An attractive approach to such large cost reduction is to replace glass and metal parts with less-expensive, lighter-weight, more-integrated polymeric components. The key challenge with polymers is to maintain performance and assure requisite durability for extended lifetimes. We have begun evaluation of several new UV-screened polycarbonate sheet glazing constructions. This has involved interactions with several major polymer industry companies to obtain improved candidate samples. Proposed absorber materials were tested for UV resistance, and appear adequate for unglazed ICS absorbers.

  12. Adsorption characterizations of fulvic acid fractions onto kaolinite.

    PubMed

    Li, Aimin; Xu, Minjuan; Li, Wenhui; Wang, Xuejun; Dai, Jingyu

    2008-01-01

    Fulvic acids extracted from a typical rice-production region near Taihu Lake of China were fractionated into three fractions including F4.8, F7.0 and F11.0 (eluted by pH 4.8 buffer, pH 7.0 buffer and pH 11.0 buffer, respectively). Sorption of fulvic acid (FA) fractions onto kaolinite was studied by batch adsorption experiments, and characterizations of kaolinite before and after adsorption were investigated using scanning electron microscopy (SEM). Adsorption isotherms of kaolinite for three FA fractions fit well with the Langmuir adsorption model. The adsorption density of the three fractions was positively correlated with the ratio of the amount of the alkyl carbon to that of carboxyl and carbonyl carbon in FA fractions and followed an order of F11.0 > F7.0 > F4.8. Hydrophobic interaction was one of the control mechanisms for the sorption of FA fraction onto kaolinite. SEM images confirmed that compared to blank kaolinite samples, kaolinite samples coated by a FA fraction displayed an opener and more dispersed conformation resulting from the disruption of the floc structure in complex. Dispersion of kaolinite after adsorption was due to the repulsion between negatively charged FA-coated particles, which is closely related to the amount of FA fractions absorbed on kaolinite.

  13. Theoretical and experimental analysis of pulse delay in bacteriorhodopsin films by a saturable absorber theory.

    PubMed

    Blaya, Salvador; Candela, Manuel; Acebal, Pablo; Carretero, Luis; Fimia, Antonio

    2014-05-19

    Time-delay of transmitted pulses with respect to the incident pulse in bacteriorhodopsin films has been studied without the use of a pump beam. Based on a modified saturable absorber model, analytical expressions of the transmitted pulse have been obtained. As a result, time delay, distortion and fractional delay have been analyzed for sinusoidal pulses with a low background. A good agreement between theory and experiences has been observed.

  14. 21 CFR 880.6025 - Absorbent tipped applicator.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Absorbent tipped applicator. 880.6025 Section 880... Devices § 880.6025 Absorbent tipped applicator. (a) Identification. An absorbent tipped applicator is a device intended for medical purposes that consists of an absorbent swab on a wooden, paper, or...

  15. The Cooling of a Liquid Absorber using a Small Cooler

    SciTech Connect

    Baynham, D.E.; Bradshaw, T.W.; Green, M.A.; Ishimoto, S.; Liggins, N.

    2005-08-24

    This report discusses the use of small cryogenic coolers for cooling the Muon Ionization Cooling Experiment (MICE) liquid cryogen absorbers. Since the absorber must be able contain liquid helium as well liquid hydrogen, the characteristics of the available 4.2 K coolers are used here. The issues associated with connecting two-stage coolers to liquid absorbers are discussed. The projected heat flows into an absorber and the cool-down of the absorbers using the cooler are presented. The warm-up of the absorber is discussed. Special hydrogen safety issues that may result from the use of a cooler on the absorbers are also discussed.

  16. Experimental Demonstration of Printed Graphene Nano-flakes Enabled Flexible and Conformable Wideband Radar Absorbers.

    PubMed

    Huang, Xianjun; Pan, Kewen; Hu, Zhirun

    2016-12-07

    In this work, we have designed, fabricated and experimentally characterized a printed graphene nano-flakes enabled flexible and conformable wideband radar absorber. The absorber covers both X (8-12 GHz) and Ku (12-18 GHz) bands and is printed on flexible substrate using graphene nano-flakes conductive ink through stencil printing method. The measured results show that an effective absorption (above 90%) bandwidth spans from 10.4 GHz to 19.7 GHz, namely a 62% fraction bandwidth, with only 2 mm thickness. The flexibility of the printed graphene nano-flakes enables the absorber conformably bending and attaching to a metal cylinder. The radar cross section (RCS) of the cylinder with and without absorber attachment has been compared and excellent absorption has been obtained. Only 3.6% bandwidth reduction has been observed comparing to that of un-bended absorber. This work has demonstrated unambiguously that printed graphene can provide flexible and conformable wideband radar absorption, which extends the graphene's application to practical RCS reductions.

  17. Experimental Demonstration of Printed Graphene Nano-flakes Enabled Flexible and Conformable Wideband Radar Absorbers

    NASA Astrophysics Data System (ADS)

    Huang, Xianjun; Pan, Kewen; Hu, Zhirun

    2016-12-01

    In this work, we have designed, fabricated and experimentally characterized a printed graphene nano-flakes enabled flexible and conformable wideband radar absorber. The absorber covers both X (8–12 GHz) and Ku (12–18 GHz) bands and is printed on flexible substrate using graphene nano-flakes conductive ink through stencil printing method. The measured results show that an effective absorption (above 90%) bandwidth spans from 10.4 GHz to 19.7 GHz, namely a 62% fraction bandwidth, with only 2 mm thickness. The flexibility of the printed graphene nano-flakes enables the absorber conformably bending and attaching to a metal cylinder. The radar cross section (RCS) of the cylinder with and without absorber attachment has been compared and excellent absorption has been obtained. Only 3.6% bandwidth reduction has been observed comparing to that of un-bended absorber. This work has demonstrated unambiguously that printed graphene can provide flexible and conformable wideband radar absorption, which extends the graphene’s application to practical RCS reductions.

  18. Infrared broadband metasurface absorber for reducing the thermal mass of a microbolometer.

    PubMed

    Jung, Joo-Yun; Song, Kyungjun; Choi, Jun-Hyuk; Lee, Jihye; Choi, Dae-Geun; Jeong, Jun-Ho; Neikirk, Dean P

    2017-03-27

    We demonstrate an infrared broadband metasurface absorber that is suitable for increasing the response speed of a microbolometer by reducing its thermal mass. A large fraction of holes are made in a periodic pattern on a thin lossy metal layer characterised with a non-dispersive effective surface impedance. This can be used as a non-resonant metasurface that can be integrated with a Salisbury screen absorber to construct an absorbing membrane for a microbolometer that can significantly reduce the thermal mass while maintaining high infrared broadband absorption in the long wavelength infrared (LWIR) band. The non-dispersive effective surface impedance can be matched to the free space by optimising the surface resistance of the thin lossy metal layer depending on the size of the patterned holes by using a dc approximation method. In experiments a high broadband absorption was maintained even when the fill factor of the absorbing area was reduced to 28% (hole area: 72%), and it was theoretically maintained even when the fill factor of the absorbing area was reduced to 19% (hole area: 81%). Therefore, a metasurface with a non-dispersive effective surface impedance is a promising solution for reducing the thermal mass of infrared microbolometer pixels.

  19. Experimental Demonstration of Printed Graphene Nano-flakes Enabled Flexible and Conformable Wideband Radar Absorbers

    PubMed Central

    Huang, Xianjun; Pan, Kewen; Hu, Zhirun

    2016-01-01

    In this work, we have designed, fabricated and experimentally characterized a printed graphene nano-flakes enabled flexible and conformable wideband radar absorber. The absorber covers both X (8–12 GHz) and Ku (12–18 GHz) bands and is printed on flexible substrate using graphene nano-flakes conductive ink through stencil printing method. The measured results show that an effective absorption (above 90%) bandwidth spans from 10.4 GHz to 19.7 GHz, namely a 62% fraction bandwidth, with only 2 mm thickness. The flexibility of the printed graphene nano-flakes enables the absorber conformably bending and attaching to a metal cylinder. The radar cross section (RCS) of the cylinder with and without absorber attachment has been compared and excellent absorption has been obtained. Only 3.6% bandwidth reduction has been observed comparing to that of un-bended absorber. This work has demonstrated unambiguously that printed graphene can provide flexible and conformable wideband radar absorption, which extends the graphene’s application to practical RCS reductions. PMID:27924823

  20. Tunable metamaterial dual-band terahertz absorber

    NASA Astrophysics Data System (ADS)

    Luo, C. Y.; Li, Z. Z.; Guo, Z. H.; Yue, J.; Luo, Q.; Yao, G.; Ji, J.; Rao, Y. K.; Li, R. K.; Li, D.; Wang, H. X.; Yao, J. Q.; Ling, F. R.

    2015-11-01

    We report a design of a temperature controlled tunable dual band terahertz absorber. The compact single unit cell consists of two nested closed square ring resonators and a layer metallic separated by a substrate strontium titanate (STO) dielectric layer. It is found that the absorber has two distinctive absorption peaks at frequencies 0.096 THz and 0.137 THz, whose peaks are attained 97% and 75%. Cooling the absorber from 400 K to 250 K causes about 25% and 27% shift compared to the resonance frequency of room temperature, when we cooling the temperature to 150 K, we could attained both the two tunabilities exceeding 53%. The frequency tunability is owing to the variation of the dielectric constant of the low-temperature co-fired ceramic (LTCC) substrate. The mechanism of the dual band absorber is attributed to the overlapping of dual resonance frequencies, and could be demonstrated by the distributions of the electric field. The method opens up avenues for designing tunable terahertz devices in detection, imaging, and stealth technology.

  1. Methods of calculating radiation absorbed dose.

    PubMed

    Wegst, A V

    1987-01-01

    The new tumoricidal radioactive agents being developed will require a careful estimate of radiation absorbed tumor and critical organ dose for each patient. Clinical methods will need to be developed using standard imaging or counting instruments to determine cumulated organ activities with tracer amounts before the therapeutic administration of the material. Standard MIRD dosimetry methods can then be applied.

  2. Moving core beam energy absorber and converter

    DOEpatents

    Degtiarenko, Pavel V.

    2012-12-18

    A method and apparatus for the prevention of overheating of laser or particle beam impact zones through the use of a moving-in-the-coolant-flow arrangement for the energy absorbing core of the device. Moving of the core spreads the energy deposition in it in 1, 2, or 3 dimensions, thus increasing the effective cooling area of the device.

  3. Composition for absorbing hydrogen from gas mixtures

    DOEpatents

    Heung, Leung K.; Wicks, George G.; Lee, Myung W.

    1999-01-01

    A hydrogen storage composition is provided which defines a physical sol-gel matrix having an average pore size of less than 3.5 angstroms which effectively excludes gaseous metal hydride poisons while permitting hydrogen gas to enter. The composition is useful for separating hydrogen gas from diverse gas streams which may have contaminants that would otherwise render the hydrogen absorbing material inactive.

  4. Shock absorbing mount for electrical components

    NASA Technical Reports Server (NTRS)

    Dillon, R. F., Jr.; Mayne, R. C. (Inventor)

    1975-01-01

    A shock mount for installing electrical components on circuit boards is described. The shock absorber is made of viscoelastic material which interconnects the electrical components. With this system, shocks imposed on one component of the circuit are not transmitted to other components. A diagram of a typical circuit is provided.

  5. How to build a molecular shock absorber.

    PubMed

    McGough, A

    1999-12-02

    Newly determined structures of the alpha-helical repeats that make up the key 'rod' domains of spectrin and alpha-actinin - which serve as spacers between their actin-binding domains - have provided important insights into how these proteins function as molecular shock absorbers in cells.

  6. Novel shock absorber features varying yield strengths

    NASA Technical Reports Server (NTRS)

    Geier, D. J.

    1964-01-01

    A shock absorbent webbing of partially drawn synthetic strands is arranged in sections of varying density related to the varying mass of the human body. This is contoured to protect the body at points of contact, when subjected to large acceleration or deceleration forces.

  7. Shock absorber protects motive components against overloads

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Shock absorber with an output shaft, hollow gear, and a pair of springs forming a resilient driving connection between shaft and gear, operates when abnormally high torques are applied. This simple durable frictional device is valuable in rotating mechanisms subject to sudden overloads.

  8. Torus elements used in effective shock absorber

    NASA Technical Reports Server (NTRS)

    Cunningham, P.; Platus, D. L.

    1966-01-01

    Energy absorbing device forces torus elements to revolve annularly between two concentric tubes when a load is applied to one tube. Interference forces can be varied by using torus elements of different thicknesses. The device operates repeatedly in compression or tension, and under problems of large onset rate tolerance or structural overload.

  9. Aldehyde-containing urea-absorbing polysaccharides

    NASA Technical Reports Server (NTRS)

    Mueller, W. A.; Hsu, G. C.; Marsh, H. E., Jr. (Inventor)

    1977-01-01

    A novel aldehyde containing polymer (ACP) is prepared by reaction of a polysaccharide with periodate to introduce aldehyde groups onto the C2 - C3 carbon atoms. By introduction of ether and ester groups onto the pendant primary hydroxyl solubility characteristics are modified. The ACP is utilized to absorb nitrogen bases such as urea in vitro or in vivo.

  10. Integrated tuned vibration absorbers: a theoretical study.

    PubMed

    Gardonio, Paolo; Zilletti, Michele

    2013-11-01

    This article presents a simulation study on two integrated tuned vibration absorbers (TVAs) designed to control the global flexural vibration of lightly damped thin structures subject to broad frequency band disturbances. The first one consists of a single axial switching TVA composed by a seismic mass mounted on variable axial spring and damper elements so that the characteristic damping and natural frequency of the absorber can be switched iteratively to control the resonant response of three flexural modes of the hosting structure. The second one consists of a single three-axes TVA composed by a seismic mass mounted on axial and rotational springs and dampers, which are arranged in such a way that the suspended mass is characterized by uncoupled heave and pitch-rolling vibrations. In this case the three damping and natural frequency parameters of the absorber are tuned separately to control three flexural modes of the hosting structure. The simulation study shows that the proposed single-unit absorbers produce, respectively, 5.3 and 8.7 dB reductions of the global flexural vibration of a rectangular plate between 20 and 120 Hz.

  11. Metamaterial Absorber Based Multifunctional Sensor Application

    NASA Astrophysics Data System (ADS)

    Ozer, Z.; Mamedov, A. M.; Ozbay, E.

    2017-02-01

    In this study metamaterial based (MA) absorber sensor, integrated with an X-band waveguide, is numerically and experimentally suggested for important application including pressure, density sensing and marble type detecting applications based on rectangular split ring resonator, sensor layer and absorber layer that measures of changing in the dielectric constant and/or the thickness of a sensor layer. Changing of physical, chemical or biological parameters in the sensor layer can be detected by measuring the resonant frequency shifting of metamaterial absorber based sensor. Suggested MA based absorber sensor can be used for medical, biological, agricultural and chemical detecting applications in microwave frequency band. We compare the simulation and experimentally obtained results from the fabricated sample which are good agreement. Simulation results show that the proposed structure can detect the changing of the refractive indexes of different materials via special resonance frequencies, thus it could be said that the MA-based sensors have high sensitivity. Additionally due to the simple and tiny structures it could be adapted to other electronic devices in different sizes.

  12. Imaging of Damped Ly-alpha Absorbers

    NASA Astrophysics Data System (ADS)

    Jim, K. T. C.; Roth, K. C.

    1998-05-01

    Intervening H I gas clouds toward QSOs give rise to damped Ly-alpha absorption. Because of the high column density (N(H I)>= 2*E(20) cm(-2) ) these systems have been thought to be galactic disks in some stage of formation. However, because potential optical counterparts have not been identified for most damped Ly-alpha systems, it is possible that some of the absorbing systems could be dwarf irregular galaxies or low surface brightness galaxies, and are thus difficult to image. In any case, the absorbers are expected to have small angular separation from the QSOs, and so high resolution imaging is required to differentiate the absorbers from the QSOs. Because previous studies have not shown any dominant morphological form for the few candidate objects known, our images are obtained with the Hawaii tip-tilt system in order to achieve the best possible morphological classification. By imaging in the NIR and optical bands that bracket the 4000 Angstroms break of these Ly-alpha absorbers, we can more readily select candidate objects by photometrically constraining their redshifts. In our sample of 14 QSOs with abosorbers from 1absorbers (Kolhatkar et al.)

  13. Identifying Fractions on Number Lines.

    ERIC Educational Resources Information Center

    Bright, George W.; And Others

    1988-01-01

    This study investigated the ways students represented fractions on number lines and the effects of instruction on those representations. The instruction primarily concerned representing fractions and ordering fractions on number lines. (Author/PK)

  14. Neutron absorbers and methods of forming at least a portion of a neutron absorber

    SciTech Connect

    Guillen, Donna P; Porter, Douglas L; Swank, W David; Erickson, Arnold W

    2014-12-02

    Methods of forming at least a portion of a neutron absorber include combining a first material and a second material to form a compound, reducing the compound into a plurality of particles, mixing the plurality of particles with a third material, and pressing the mixture of the plurality of particles and the third material. One or more components of neutron absorbers may be formed by such methods. Neutron absorbers may include a composite material including an intermetallic compound comprising hafnium aluminide and a matrix material comprising pure aluminum.

  15. Release Fraction Evaluation

    SciTech Connect

    Bamberger, Judith A.; Glissmeyer, John A.

    2004-01-01

    This document presents results of experiments conducted to measure release fractions during certain tank retrieval processes. The tests were performed in a 1/4 scale model of a waste storage tank. The retrieval processes simulated were: (1) Discharging liquid or slurry from the mouth of a vertically oriented two-in. Schedule 40 pipe. The discharging material was in free-fall from the mouth of the pipe near the top of the tank into a liquid or slurry pool at the bottom of the tank. (2) The jet from a 9/16-in.-diameter nozzle transferring liquid or slurry waste from one side of the tank to the other. The discharging liquid was aimed at the opposite side of the tank from the nozzle and either impacted the tank wall or fell into a liquid or slurry pool in the bottom of the tank. (3) A high pressure fan jet of liquid striking a steel plate or simulated waste from a stand-off distance of a few inches. For each process, a water-soluble fluorescent dye was added to the liquid fraction as a tracer. Kaolin clay was used to represent the solids. The tank was covered and there was no forced ventilation in the tank during the tests. Six air samples were collected during each test. The air samples were collected at fixed positions in the tank. The air sample filters were dried and weighed to determine the solids collection. The fluorescent dye was then leached from each filter and quantified with a fluorometer to determine the collection of liquid. Samples of the slurry and liquid simulants were also collected to determine the quantities of simulant used in each test. To calculate the release fraction, the quantity collected on each air sample was adjusted for the fraction of the tank volume sampled and divided by the quantity of material exposed in the simulation. The method was not as sensitive for the solids content as it was for the liquid content, but in those instances where a solids release fraction was determined, it was in relatively good agreement with that of the

  16. FRACTIONAL CRYSTALLIZATION FEED ENVELOPE

    SciTech Connect

    HERTING DL

    2008-03-19

    Laboratory work was completed on a set of evaporation tests designed to establish a feed envelope for the fractional crystallization process. The feed envelope defines chemical concentration limits within which the process can be operated successfully. All 38 runs in the half-factorial design matrix were completed successfully, based on the qualitative definition of success. There is no feed composition likely to be derived from saltcake dissolution that would cause the fractional crystallization process to not meet acceptable performance requirements. However, some compositions clearly would provide more successful operation than other compositions.

  17. Absorbed dose thresholds and absorbed dose rate limitations for studies of electron radiation effects on polyetherimides

    NASA Technical Reports Server (NTRS)

    Long, Edward R., Jr.; Long, Sheila Ann T.; Gray, Stephanie L.; Collins, William D.

    1989-01-01

    The threshold values of total absorbed dose for causing changes in tensile properties of a polyetherimide film and the limitations of the absorbed dose rate for accelerated-exposure evaluation of the effects of electron radiation in geosynchronous orbit were studied. Total absorbed doses from 1 kGy to 100 MGy and absorbed dose rates from 0.01 MGy/hr to 100 MGy/hr were investigated, where 1 Gy equals 100 rads. Total doses less than 2.5 MGy did not significantly change the tensile properties of the film whereas doses higher than 2.5 MGy significantly reduced elongation-to-failure. There was no measurable effect of the dose rate on the tensile properties for accelerated electron exposures.

  18. Design of a non-traditional dynamic vibration absorber.

    PubMed

    Cheung, Y L; Wong, W O

    2009-08-01

    A non-traditional dynamic vibration absorber is proposed for the minimization of maximum vibration velocity response of a vibrating structure. Unlike the traditional damped absorber configuration, the proposed absorber has a linear viscous damper connecting the absorber mass directly to the ground instead of the main mass. Optimum parameters of the proposed absorber are derived based on the fixed-point theory for minimizing the maximum vibration velocity response of a single-degree-of-freedom system under harmonic excitation. The extent of reduction in maximum vibration velocity response of the primary system when using the traditional dynamic absorber is compared with that using the proposed one. Under the optimum tuning condition of the absorbers, it is proved analytically that the proposed absorber provides a greater reduction in maximum vibration velocity response of the primary system than the traditional absorber.

  19. Momentum fractionation on superstrata

    SciTech Connect

    Bena, Iosif; Martinec, Emil; Turton, David; Warner, Nicholas P.

    2016-05-11

    Superstrata are bound states in string theory that carry D1, D5, and momentum charges, and whose supergravity descriptions are parameterized by arbitrary functions of (at least) two variables. In the D1-D5 CFT, typical three-charge states reside in highdegree twisted sectors, and their momentum charge is carried by modes that individually have fractional momentum. Understanding this momentum fractionation holographically is crucial for understanding typical black-hole microstates in this system. We use solution-generating techniques to add momentum to a multi-wound supertube and thereby construct the first examples of asymptotically-flat superstrata. The resulting supergravity solutions are horizonless and smooth up to well-understood orbifold singularities. Upon taking the AdS3 decoupling limit, our solutions are dual to CFT states with momentum fractionation. We give a precise proposal for these dual CFT states. Lastly, our construction establishes the very nontrivial fact that large classes of CFT states with momentum fractionation can be realized in the bulk as smooth horizonless supergravity solutions.

  20. Momentum fractionation on superstrata

    DOE PAGES

    Bena, Iosif; Martinec, Emil; Turton, David; ...

    2016-05-11

    Superstrata are bound states in string theory that carry D1, D5, and momentum charges, and whose supergravity descriptions are parameterized by arbitrary functions of (at least) two variables. In the D1-D5 CFT, typical three-charge states reside in highdegree twisted sectors, and their momentum charge is carried by modes that individually have fractional momentum. Understanding this momentum fractionation holographically is crucial for understanding typical black-hole microstates in this system. We use solution-generating techniques to add momentum to a multi-wound supertube and thereby construct the first examples of asymptotically-flat superstrata. The resulting supergravity solutions are horizonless and smooth up to well-understood orbifoldmore » singularities. Upon taking the AdS3 decoupling limit, our solutions are dual to CFT states with momentum fractionation. We give a precise proposal for these dual CFT states. Lastly, our construction establishes the very nontrivial fact that large classes of CFT states with momentum fractionation can be realized in the bulk as smooth horizonless supergravity solutions.« less

  1. Sweet Work with Fractions

    ERIC Educational Resources Information Center

    Vinogradova, Natalya; Blaine, Larry

    2013-01-01

    Almost everyone loves chocolate. However, the same cannot be said about fractions, which are loved by markedly fewer. Middle school students tend to view them with wary respect, but little affection. The authors attempt to sweeten the subject by describing a type of game involving division of chocolate bars. The activity they describe provides a…

  2. Field-Flow Fractionation.

    ERIC Educational Resources Information Center

    Caldwell, Karin D.

    1988-01-01

    Describes a technique for separating samples that range over 15 orders of magnitude in molecular weight. Discusses theory, apparatus, and sample preparation techniques. Lists several types of field-flow fractionation (FFF) and their uses: sedimentation FFF, thermal FFF, flow FFF, electrical FFF, and steric FFF. (ML)

  3. Fraction collector for electrophoresis

    NASA Technical Reports Server (NTRS)

    Bier, M.

    1977-01-01

    Rotating-tube electrophoresis apparatus employs rotating jet of eluting buffer to reduce effects of convection during separation. Designed for separation of microorganisms and biological species, system combines gravity/gradient compensating of lumen with buffer flush at fraction outlet to increase separation efficiency.

  4. Black carbon and other light-absorbing aerosols in snow

    NASA Astrophysics Data System (ADS)

    Wang, X.; Doherty, S. J.; Warren, S. G.; Fu, Q.

    2011-12-01

    Black carbon (BC), organic carbon (OC), and mineral dust are the most important light-absorbing aerosols (LAA) in snow. The physical, chemical and optical properties of these aerosols differ greatly; the different spectral dependences of their light-absorption can be used to quantify their concentrations in snow. A field campaign was conducted in January and February of 2010 to measure the LAA in snow across northern China. About 400 snow samples were collected at 46 sites in 6 provinces (Huang et al. 2011). Light absorption by mineral dust is due to iron oxides, so iron was determined by chemical analysis of filters and meltwater. To obtain concentrations of the absorbers, BC, OC, and Fe were assumed to have mass absorption cross-sections at 550 nm of 6.3, 0.3, and 0.9 m2/g respectively, and absorption Ångstrom exponents of 1.1, 6, and 3. The lowest values of all LAA are in the remote northeast, at latitude 51°N on the border of Siberia.Median values in surface snow there are 75 ppb BC, 150 ppb OC, and 45 ppb Fe. Farther south, in the industrial northeast, median values are 1000 ppb BC, 4200 ppb OC, and 500 ppb Fe. The grassland of Inner Mongolia is dominated by OC in soil dust of local origin: 560 ppb BC, 8000 ppb OC, 430 ppb Fe. In the Qilian Mountains at the northern boundary of the Tibetan Plateau the surface snow has 70 ppb BC, 2800 ppb OC, and 550 ppb Fe. The fraction of light absorption due to Fe is ~30% in the Qilian Mountains. Elsewhere BC and OC dominate the absorption, so Fe contributes <10% even though the Fe concentrations are as high as the Qilian values.

  5. A Solar Volumetric Receiver: Influence of Absorbing Cells Configuration on Device Thermal Performance

    NASA Astrophysics Data System (ADS)

    Yilbas, B. S.; Shuja, S. Z.

    2017-01-01

    Thermal performance of a solar volumetric receiver incorporating the different cell geometric configurations is investigated. Triangular, hexagonal, and rectangular absorbing cells are incorporated in the analysis. The fluid volume fraction, which is the ratio of the volume of the working fluid over the total volume of solar volumetric receiver, is introduced to assess the effect of cell size on the heat transfer rates in the receiver. In this case, reducing the fluid volume fraction corresponds to increasing cell size in the receiver. SiC is considered as the cell material, and air is used as the working fluid in the receiver. The Lambert's Beer law is incorporated to account for the solar absorption in the receiver. A finite element method is used to solve the governing equation of flow and heat transfer. It is found that the fluid volume fraction has significant effect on the flow field in the solar volumetric receiver, which also modifies thermal field in the working fluid. The triangular absorbing cell gives rise to improved effectiveness of the receiver and then follows the hexagonal and rectangular cells. The second law efficiency of the receiver remains high when hexagonal cells are used. This occurs for the fluid volume fraction ratio of 0.5.

  6. Imaging highly absorbing nanoparticles using photothermal microscopy

    NASA Astrophysics Data System (ADS)

    Lussier, Simon-Alexandre; Moradi, Hamid; Price, Alain; Murugkar, Sangeeta

    2015-03-01

    Gold nanoparticles (NPs) have tremendous potential in biomedicine. They can be used as absorbing labels inside living cells for the purpose of biomedical imaging, biosensing as well as for photothermal therapy. We demonstrate photothermal imaging of highly-absorbing particles using a pump-probe setup. The photothermal signal is recovered by heterodyne detection, where the excitation pump laser is at 532 nm and the probe laser is at 638 nm. The sample is moved by a scanning stage. Proof of concept images of red polystyrene microspheres and gold nanoparticles are obtained with this home-built multimodal microscope. The increase in temperature at the surface of the gold NPs, due to the pump laser beam, can be directly measured by means of this photothermal microscope and then compared with the results from theoretical predictions. This technique will be useful for characterization of nanoparticles of different shapes, sizes and materials that are used in cancer diagnosis and therapy.

  7. Infrared bolometers with silicon nitride micromesh absorbers

    NASA Technical Reports Server (NTRS)

    Bock, J. J.; Turner, A. D.; DelCastillo, H. M.; Beeman, J. W.; Lange, A. E.; Mauskopf, P. D.

    1996-01-01

    Sensitive far infrared and millimeter wave bolometers fabricated from a freestanding membrane of low stress silicon nitride are reported. The absorber, consisting of a metallized silicon nitride micromesh thermally isolated by radial legs of silicon nitride, is placed in an integrating cavity to efficiently couple to single mode or multiple mode infrared radiation. This structure provides low heat capacity, low thermal conduction and minimal cross section to energetic particles. A neutron transmutation doped Ge thermister is bump bonded to the center of the device and read out with evaporated Cr-Au leads. The limiting performance of the micromesh absorber is discussed and the recent results obtained from a 300 mK cold stage are summarized.

  8. Impedance matched thin metamaterials make metals absorbing

    PubMed Central

    Mattiucci, N.; Bloemer, M. J.; Aközbek, N.; D'Aguanno, G.

    2013-01-01

    Metals are generally considered good reflectors over the entire electromagnetic spectrum up to their plasma frequency. Here we demonstrate an approach to tailor their absorbing characteristics based on the effective metamaterial properties of thin, periodic metallo-dielectric multilayers by exploiting a broadband, inherently non-resonant, surface impedance matching mechanism. Based on this mechanism, we design, fabricate and test omnidirectional, thin (<1 micron), polarization independent, extremely efficient absorbers (in principle being capable to reach A > 99%) over a frequency range spanning from the UV to the IR. Our approach opens new venues to design cost effective materials for many applications such as thermo-photovoltaic energy conversion devices, light harvesting for solar cells, flat panel display, infrared detectors, stray light reduction, stealth and others. PMID:24220284

  9. A sound absorbing metasurface with coupled resonators

    NASA Astrophysics Data System (ADS)

    Li, Junfei; Wang, Wenqi; Xie, Yangbo; Popa, Bogdan-Ioan; Cummer, Steven A.

    2016-08-01

    An impedance matched surface is able, in principle, to totally absorb the incident sound and yield no reflection, and this is desired in many acoustic applications. Here we demonstrate a design of impedance matched sound absorbing surface with a simple construction. By coupling different resonators and generating a hybrid resonance mode, we designed and fabricated a metasurface that is impedance-matched to airborne sound at tunable frequencies with subwavelength scale unit cells. With careful design of the coupled resonators, over 99% energy absorption at central frequency of 511 Hz with a 50% absorption bandwidth of 140 Hz is achieved experimentally. The proposed design can be easily fabricated, and is mechanically stable. The proposed metasurface can be used in many sound absorption applications such as loudspeaker design and architectural acoustics.

  10. Absorbing Software Testing into the Scrum Method

    NASA Astrophysics Data System (ADS)

    Tuomikoski, Janne; Tervonen, Ilkka

    In this paper we study, how to absorb software testing into the Scrum method. We conducted the research as an action research during the years 2007-2008 with three iterations. The result showed that testing can and even should be absorbed to the Scrum method. The testing team was merged into the Scrum teams. The teams can now deliver better working software in a shorter time, because testing keeps track of the progress of the development. Also the team spirit is higher, because the Scrum team members are committed to the same goal. The biggest change from test manager’s point of view was the organized Product Owner Team. Test manager don’t have testing team anymore, and in the future all the testing tasks have to be assigned through the Product Backlog.

  11. The ultimate chrome absorber in photomask making

    NASA Astrophysics Data System (ADS)

    Hashimoto, Masahiro; Iwashita, Hiroyuki; Kominato, Atsushi; Shishido, Hiroaki; Ushida, Masao; Mitsui, Hideaki

    2008-05-01

    193nm-immersion lithography is the most promising technology for 32nm-node device fabrication. A new Cr absorber (TFC) for 193-nm attenuated phase-shift blanks was developed to meet the photomask requirements without any additional process step, such as hardmask etching. TFC was introduced with a design concept of the vertical profile for shorter etching time, the over etching time reduction. As a result, the dry-etching time was dramatically improved by more than 20% shorter than the conventional Cr absorber (TF11) without any process changes. We confirmed that 150nm-resist thickness was possible by TFC. The 32nm technology-node requirement is fully supported by TFC with thinner CAR, such as resolution and CD performance.

  12. Accelerated life testing of solar absorber coatings

    NASA Astrophysics Data System (ADS)

    Carlsson, Bo; Moeller, K.; Frei, Ulrich; Koehl, Michael

    1994-09-01

    Results from a comprehensive case study on accelerated life testing of some selective solar collector absorber coatings for DHW systems are reviewed. The study was conducted within Task X `Solar Materials Research and Development' of the IEA Solar Heating and Cooling Program from 1987 to 1992 and is unique due to its quantitative and systematic approach for durability assessment. The work of case study involved the development of both experimental and theoretical tools to aid the assessment of service life or absorber coatings. This entailed performance analysis, failure analysis, microclimate characterization, environmental resistance testing and life date analysis. Predicted in-service degradation of coatings from accelerated life testing was found to be in fairly good agreement both qualitatively and quantitatively with what was actually observed on coatings installed and tested for three years in solar collectors working under typical DHW conditions.

  13. Fault Detection for Automotive Shock Absorber

    NASA Astrophysics Data System (ADS)

    Hernandez-Alcantara, Diana; Morales-Menendez, Ruben; Amezquita-Brooks, Luis

    2015-11-01

    Fault detection for automotive semi-active shock absorbers is a challenge due to the non-linear dynamics and the strong influence of the disturbances such as the road profile. First obstacle for this task, is the modeling of the fault, which has been shown to be of multiplicative nature. Many of the most widespread fault detection schemes consider additive faults. Two model-based fault algorithms for semiactive shock absorber are compared: an observer-based approach and a parameter identification approach. The performance of these schemes is validated and compared using a commercial vehicle model that was experimentally validated. Early results shows that a parameter identification approach is more accurate, whereas an observer-based approach is less sensible to parametric uncertainty.

  14. Investigations on Absorber Materials at Cryogenic Temperatures

    SciTech Connect

    Marhauser, Frank; Elliott, Thomas; Rimmer, Robert

    2009-05-01

    In the framework of the 12 GeV upgrade project for the Continuous Electron Beam Accelerator Facility (CEBAF) improvements are being made to refurbish cryomodules housing Thomas Jefferson National Accelerator Facility's (JLab) original 5-cell cavities. Recently we have started to look into a possible simplification of the existing Higher Order Mode (HOM) absorber design combined with the aim to find alternative material candidates. The absorbers are implemented in two HOM-waveguides immersed in the helium bath and operate at 2 K temperature. We have built a cryogenic setup to perform measurements on sample load materials to investigate their lossy characteristics and variations from room temperature down to 2 K. Initial results are presented in this paper.

  15. Shock wave absorber having apertured plate

    DOEpatents

    Shin, Y.W.; Wiedermann, A.H.; Ockert, C.E.

    1983-08-26

    The shock or energy absorber disclosed herein utilizes an apertured plate maintained under the normal level of liquid flowing in a piping system and disposed between the normal liquid flow path and a cavity pressurized with a compressible gas. The degree of openness (or porosity) of the plate is between 0.01 and 0.60. The energy level of a shock wave travelling down the piping system thus is dissipated by some of the liquid being jetted through the apertured plate toward the cavity. The cavity is large compared to the quantity of liquid jetted through the apertured plate, so there is little change in its volume. The porosity of the apertured plate influences the percentage of energy absorbed.

  16. Shock wave absorber having apertured plate

    DOEpatents

    Shin, Yong W.; Wiedermann, Arne H.; Ockert, Carl E.

    1985-01-01

    The shock or energy absorber disclosed herein utilizes an apertured plate maintained under the normal level of liquid flowing in a piping system and disposed between the normal liquid flow path and a cavity pressurized with a compressible gas. The degree of openness (or porosity) of the plate is between 0.01 and 0.60. The energy level of a shock wave travelling down the piping system thus is dissipated by some of the liquid being jetted through the apertured plate toward the cavity. The cavity is large compared to the quantity of liquid jetted through the apertured plate, so there is little change in its volume. The porosity of the apertured plate influences the percentage of energy absorbed.

  17. Vibration absorber modeling for handheld machine tool

    NASA Astrophysics Data System (ADS)

    Abdullah, Mohd Azman; Mustafa, Mohd Muhyiddin; Jamil, Jazli Firdaus; Salim, Mohd Azli; Ramli, Faiz Redza

    2015-05-01

    Handheld machine tools produce continuous vibration to the users during operation. This vibration causes harmful effects to the health of users for repeated operations in a long period of time. In this paper, a dynamic vibration absorber (DVA) is designed and modeled to reduce the vibration generated by the handheld machine tool. Several designs and models of vibration absorbers with various stiffness properties are simulated, tested and optimized in order to diminish the vibration. Ordinary differential equation is used to derive and formulate the vibration phenomena in the machine tool with and without the DVA. The final transfer function of the DVA is later analyzed using commercial available mathematical software. The DVA with optimum properties of mass and stiffness is developed and applied on the actual handheld machine tool. The performance of the DVA is experimentally tested and validated by the final result of vibration reduction.

  18. Disposable Diaper Absorbency: Improvements via Advanced Designs.

    PubMed

    Helmes, C Tucker; O'Connor, Robert; Sawyer, Larry; Young, Sharon

    2014-08-01

    Absorbency effectiveness in diapers has improved significantly in recent years with the advent of new ingredient combinations and advanced design features. With these features, many leading products maintain their dryness performance overnight. Considering the importance of holding liquid away from the skin, ongoing research in diaper construction focuses on strategies to increase the effectiveness to capture liquid and help avoid rewetting of infant skin. The layout and design of a disposable diaper allows for distribution of absorbency features where they can provide the optimal benefit. Clinical evidence indicates materials can keep moisture away from the skin in the diapered area, helping maintain proper skin hydration, minimizing irritation, and contributing to reduced rates of diaper rash.

  19. Wide band cryogenic ultra-high vacuum microwave absorber

    DOEpatents

    Campisi, I.E.

    1992-05-12

    An absorber waveguide assembly for absorbing higher order modes of microwave energy under cryogenic ultra-high vacuum conditions, that absorbs wide-band multi-mode energy. The absorber is of a special triangular shape, made from flat tiles of silicon carbide and aluminum nitride. The leading sharp end of the absorber is located in a corner of the waveguide and tapers to a larger cross-sectional area whose center is located approximately in the center of the wave guide. The absorber is relatively short, being of less height than the maximum width of the waveguide. 11 figs.

  20. Wide band cryogenic ultra-high vacuum microwave absorber

    DOEpatents

    Campisi, Isidoro E.

    1992-01-01

    An absorber wave guide assembly for absorbing higher order modes of microwave energy under cryogenic ultra-high vacuum conditions, that absorbs wide-band multi-mode energy. The absorber is of a special triangular shape, made from flat tiles of silicon carbide and aluminum nitride. The leading sharp end of the absorber is located in a corner of the wave guide and tapers to a larger cross-sectional area whose center is located approximately in the center of the wave guide. The absorber is relatively short, being of less height than the maximum width of the wave guide.

  1. Tech Transfer Webinar: Energy Absorbing Materials

    ScienceCinema

    Duoss, Eric

    2016-07-12

    A new material has been designed and manufactured at LLNL that can absorb mechanical energy--a cushion--while also providing protection against sheering. This ordered cellular material is 3D printed using direct ink writing techniques under development at LLNL. It is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  2. Metamaterial Resonant Absorbers for Terahertz Sensing

    DTIC Science & Technology

    2015-12-01

    and their periodic nature , finite element (FE) modeling is the preferable means of designing metamaterials. In order to use metamaterials in sensors ...will incorporate the metamaterial absorber design of this research into a more efficient, cost effective, bi-material THz sensor that can be employed...in a variety of naval applications. 14. SUBJECT TERMS terahertz sensors , metamaterials, uncooled detectors 15. NUMBER OF PAGES 73 16

  3. Lightweight Energy Absorbers for Blast Containers

    NASA Technical Reports Server (NTRS)

    Balles, Donald L.; Ingram, Thomas M.; Novak, Howard L.; Schricker, Albert F.

    2003-01-01

    Kinetic-energy-absorbing liners made of aluminum foam have been developed to replace solid lead liners in blast containers on the aft skirt of the solid rocket booster of the space shuttle. The blast containers are used to safely trap the debris from small explosions that are initiated at liftoff to sever frangible nuts on hold-down studs that secure the spacecraft to a mobile launch platform until liftoff.

  4. Design and Manufacture of Energy Absorbing Materials

    ScienceCinema

    Duoss, Eric

    2016-07-12

    Learn about an ordered cellular material that has been designed and manufactured using direct ink writing (DIW), a 3-D printing technology being developed at LLNL. The new material is a patterned cellular material that can absorb mechanical energy-a cushion-while also providing protection against sheering. This material is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  5. Tech Transfer Webinar: Energy Absorbing Materials

    SciTech Connect

    Duoss, Eric

    2014-06-17

    A new material has been designed and manufactured at LLNL that can absorb mechanical energy--a cushion--while also providing protection against sheering. This ordered cellular material is 3D printed using direct ink writing techniques under development at LLNL. It is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  6. Design and Manufacture of Energy Absorbing Materials

    SciTech Connect

    Duoss, Eric

    2014-05-28

    Learn about an ordered cellular material that has been designed and manufactured using direct ink writing (DIW), a 3-D printing technology being developed at LLNL. The new material is a patterned cellular material that can absorb mechanical energy-a cushion-while also providing protection against sheering. This material is expected to find utility in application spaces that currently use unordered foams, such as sporting and consumer goods as well as defense and aerospace.

  7. Shock wave absorber having a deformable liner

    DOEpatents

    Youngdahl, C.K.; Wiedermann, A.H.; Shin, Y.W.; Kot, C.A.; Ockert, C.E.

    1983-08-26

    This invention discloses a shock wave absorber for a piping system carrying liquid. The absorber has a plastically deformable liner defining the normal flow boundary for an axial segment of the piping system, and a nondeformable housing is spaced outwardly from the liner so as to define a gas-tight space therebetween. The flow capacity of the liner generally corresponds to the flow capacity of the piping system line, but the liner has a noncircular cross section and extends axially of the piping system line a distance between one and twenty times the diameter thereof. Gas pressurizes the gas-tight space equal to the normal liquid pressure in the piping system. The liner has sufficient structural capacity to withstand between one and one-half and two times this normal liquid pressures; but at greater pressures it begins to plastically deform initially with respect to shape to a more circular cross section, and then with respect to material extension by circumferentially stretching the wall of the liner. A high energy shock wave passing through the liner thus plastically deforms the liner radially into the gas space and progressively also as needed in the axial direction of the shock wave to minimize transmission of the shock wave beyond the absorber.

  8. Microscopic modeling of nitride intersubband absorbance

    NASA Astrophysics Data System (ADS)

    Montano, Ines; Allerman, A. A.; Wierer, J. J.; Moseley, M.; Skogen, E. J.; Tauke-Pedretti, A.; Vawter, G. A.

    III-nitride intersubband structures have recently attracted much interest because of their potential for a wide variety of applications ranging from electro-optical modulators to terahertz quantum cascade lasers. To overcome present simulation limitations we have developed a microscopic absorbance simulator for nitride intersubband devices. Our simulator calculates the band structure of nitride intersubband systems using a fully coupled 8x8 k.p Hamiltonian and determines the material response of a single period in a density-matrix-formalism by solving the Heisenberg equation including many-body and dephasing contributions. After calculating the polarization due to intersubband transitions in a single period, the resulting absorbance of a superlattice structure including radiative coupling between the different periods is determined using a non-local Green's-function formalism. As a result our simulator allows us to predict intersubband absorbance of superlattice structures with microscopically determined lineshapes and linewidths accounting for both many-body and correlation contributions. This work is funded by Sandia National Laboratories Laboratory Directed Research and Development program. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin.

  9. COSMIC DUST IN Mg II ABSORBERS

    SciTech Connect

    Menard, Brice; Fukugita, Masataka

    2012-08-01

    Mg II absorbers induce reddening on background quasars. We measure this effect and infer the cosmic density of dust residing in these systems to be {Omega} Almost-Equal-To 2 Multiplication-Sign 10{sup -6}, in units of the critical density of the universe, which is comparable to the amount of dust found in galactic disks or about half the amount inferred to exist outside galaxies. We also estimate the neutral hydrogen abundance in Mg II clouds to be {Omega} Almost-Equal-To 1.5 Multiplication-Sign 10{sup -4}, which is approximately 5% of hydrogen in stars in galaxies. This implies a dust-to-gas mass ratio for Mg II clouds of about 1/100, which is similar to the value for normal galaxies. This would support the hypothesis of the outflow origin of Mg II clouds, which are intrinsically devoid of stars and hence have no sources of dust. Considerations of the dust abundance imply that the presence of Mg II absorbers around galaxies lasts effectively for a few Gyr. High-redshift absorbers allow us to measure the rest-frame extinction curve to 900 A, at which the absorption by the Lyman edge dominates over scattering by dust in the extinction opacity.

  10. Heaving buoys, point absorbers and arrays.

    PubMed

    Falnes, Johannes; Hals, Jørgen

    2012-01-28

    Absorption of wave energy may be considered as a phenomenon of interference between incident and radiated waves generated by an oscillating object; a wave-energy converter (WEC) that displaces water. If a WEC is very small in comparison with one wavelength, it is classified as a point absorber (PA); otherwise, as a 'quasi-point absorber'. The latter may be a dipole-mode radiator, for instance an immersed body oscillating in the surge mode or pitch mode, while a PA is so small that it should preferably be a source-mode radiator, for instance a heaving semi-submerged buoy. The power take-off capacity, the WEC's maximum swept volume and preferably also its full physical volume should be reasonably matched to the wave climate. To discuss this matter, two different upper bounds for absorbed power are applied in a 'Budal diagram'. It appears that, for a single WEC unit, a power capacity of only about 0.3 MW matches well to a typical offshore wave climate, and the full physical volume has, unfortunately, to be significantly larger than the swept volume, unless phase control is used. An example of a phase-controlled PA is presented. For a sizeable wave-power plant, an array consisting of hundreds, or even thousands, of mass-produced WEC units is required.

  11. Load limiting energy absorbing lightweight debris catcher

    NASA Technical Reports Server (NTRS)

    Kahn, Jon B. (Inventor); Schneider, William C. (Inventor)

    1991-01-01

    In the representative embodiment of the invention disclosed, a load limiting, energy absorbing net is arranged to overlay a normally-covered vent opening in the rear bulkhead of the space orbiter vehicle. Spatially-disposed flexible retainer straps are extended from the net and respectively secured to bulkhead brackets spaced around the vent opening. The intermediate portions of the straps are doubled over and stitched together in a pattern enabling the doubled-over portions to progressively separate at a predicable load designed to be well below the tensile capability of the straps as the stitches are successively torn apart by the forces imposed on the retainer members whenever the cover plate is explosively separated from the bulkhead and propelled into the net. By arranging these stitches to be successively torn away at a load below the strap strength in response to forces acting on the retainers that are less than the combined strength of the retainers, this tearing action serves as a predictable compact energy absorber for safely halting the cover plate as the retainers are extended as the net is deployed. The invention further includes a block of an energy-absorbing material positioned in the net for receiving loose debris produced by the explosive release of the cover plate.

  12. Gallbladder perforation by absorbable spiral tacker

    PubMed Central

    Wirsching, A; Vonlanthen, R

    2014-01-01

    Introduction Mesh fixation with tacker systems is common in laparoscopic and open hernia repair. Complications due to absorbable tackers are rare and have not been described in the literature. However, we report a case of gallbladder erosion due to tacker dislocation. Methods An open hernia repair was performed using an intraperitoneal onlay mesh for a recurrent parastomal hernia after two previous mesh repairs in a 67-year-old patient. Results On postoperative day 2, the patient was reoperated because of a dislocated tacker that eroded and perforated the fundus region of the gallbladder. Putatively, tacker dislocation occurred owing to imbalanced traction forces. Initially, the mesh was fixed with absorbable tackers around the stoma on the right and transmuscular suture fixation was carried out on the left abdominal side. On revision surgery, tension forces to the right were therefore neutralised by additional transmuscular sutures on the right side. Conclusions Absorbable tackers in open hernia repair provide a safe and effective mesh fixation if tension forces are carefully avoided. PMID:25245719

  13. Development of monofilar rotor hub vibration absorber

    NASA Technical Reports Server (NTRS)

    Duh, J.; Miao, W.

    1983-01-01

    A design and ground test program was conducted to study the performance of the monofilar absorber for vibration reduction on a four-bladed helicopter. A monofilar is a centrifugal tuned two degree-of-freedom rotor hub absorber that provides force attenuation at two frequencies using the same dynamic mass. Linear and non-linear analyses of the coupled monofilar/airframe system were developed to study tuning and attenuation characteristics. Based on the analysis, a design was fabricated and impact bench tests verified the calculated non-rotating natural frequencies and mode shapes. Performance characteristics were measured using a rotating absorber test facility. These tests showed significant attenuation of fixed-system 4P hub motions due to 3P inplane rotating-system hub forces. In addition, detuning effects of the 3P monofilar modal response were small due to the nonlinearities and tuning pin slippage. However, attenuation of 4P hub motions due to 5P inplane hub forces was poor. The performance of the 5P monofilar modal response was degraded by torsional motion of the dynamic mass relative to the support arm which resulted in binding of the dynamic components. Analytical design studies were performed to evaluate this torsional motion problem. An alternative design is proposed which may alleviate the torsional motion of the dynamic mass.

  14. Timing the warm absorber in NGC4051

    NASA Astrophysics Data System (ADS)

    Silva, C.; Uttley, P.; Costantini, E.

    2015-07-01

    In this work we have combined spectral and timing analysis in the characterization of highly ionized outflows in Seyfert galaxies, the so-called warm absorbers. Here, we present our results on the extensive ˜600ks of XMM-Newton archival observations of the bright and highly variable Seyfert 1 galaxy NGC4051, whose spectrum has revealed a complex multi-component wind. Working simultaneously with RGS and PN data, we have performed a detailed analysis using a time-dependent photoionization code in combination with spectral and Fourier timing techniques. This method allows us to study in detail the response of the gas due to variations in the ionizing flux of the central source. As a result, we will show the contribution of the recombining gas to the time delays of the most highly absorbed energy bands relative to the continuum (Silva, Uttley & Costantini in prep.), which is also vital information for interpreting the continuum lags associated with propagation and reverberation effects in the inner emitting regions. Furthermore, we will illustrate how this powerful method can be applied to other sources and warm-absorber configurations, allowing for a wide range of studies.

  15. Fabrication of an Absorber-Coupled MKID Detector

    NASA Technical Reports Server (NTRS)

    Brown, Ari; Hsieh, Wen-Ting; Moseley, Samuel; Stevenson, Thomas; U-Yen, Kongpop; Wollack, Edward

    2012-01-01

    Absorber-coupled microwave kinetic inductance detector (MKID) arrays were developed for submillimeter and far-infrared astronomy. These sensors comprise arrays of lambda/2 stepped microwave impedance resonators patterned on a 1.5-mm-thick silicon membrane, which is optimized for optical coupling. The detector elements are supported on a 380-mm-thick micro-machined silicon wafer. The resonators consist of parallel plate aluminum transmission lines coupled to low-impedance Nb microstrip traces of variable length, which set the resonant frequency of each resonator. This allows for multiplexed microwave readout and, consequently, good spatial discrimination between pixels in the array. The transmission lines simultaneously act to absorb optical power and employ an appropriate surface impedance and effective filling fraction. The fabrication techniques demonstrate high-fabrication yield of MKID arrays on large, single-crystal membranes and sub-micron front-to-back alignment of the micro strip circuit. An MKID is a detector that operates upon the principle that a superconducting material s kinetic inductance and surface resistance will change in response to being exposed to radiation with a power density sufficient to break its Cooper pairs. When integrated as part of a resonant circuit, the change in surface impedance will result in a shift in its resonance frequency and a decrease of its quality factor. In this approach, incident power creates quasiparticles inside a superconducting resonator, which is configured to match the impedance of free space in order to absorb the radiation being detected. For this reason MKIDs are attractive for use in large-format focal plane arrays, because they are easily multiplexed in the frequency domain and their fabrication is straightforward. The fabrication process can be summarized in seven steps: (1) Alignment marks are lithographically patterned and etched all the way through a silicon on insulator (SOI) wafer, which consists of a

  16. Young Children's Notations for Fractions

    ERIC Educational Resources Information Center

    Brizuela, Barbara M.

    2006-01-01

    This paper focuses on the kinds of notations young children make for fractional numbers. The extant literature in the area of fractional numbers acknowledges children's difficulties in conceptualizing fractional numbers. Some of the research suggests possibly delaying an introduction to conventional notations for algorithms and fractions until…

  17. Creating, Naming, and Justifying Fractions

    ERIC Educational Resources Information Center

    Siebert, Daniel; Gaskin, Nicole

    2006-01-01

    For students to develop meaningful conceptions of fractions and fraction operations, they need to think of fractions in terms other than as just whole-number combinations. In this article, we suggest two powerful images for thinking about fractions that move beyond whole-number reasoning. (Contains 5 figures.)

  18. Arbitrage with fractional Gaussian processes

    NASA Astrophysics Data System (ADS)

    Zhang, Xili; Xiao, Weilin

    2017-04-01

    While the arbitrage opportunity in the Black-Scholes model driven by fractional Brownian motion has a long history, the arbitrage strategy in the Black-Scholes model driven by general fractional Gaussian processes is in its infancy. The development of stochastic calculus with respect to fractional Gaussian processes allowed us to study such models. In this paper, following the idea of Shiryaev (1998), an arbitrage strategy is constructed for the Black-Scholes model driven by fractional Gaussian processes, when the stochastic integral is interpreted in the Riemann-Stieltjes sense. Arbitrage opportunities in some fractional Gaussian processes, including fractional Brownian motion, sub-fractional Brownian motion, bi-fractional Brownian motion, weighted-fractional Brownian motion and tempered fractional Brownian motion, are also investigated.

  19. Electrochromic absorbance changes in spinach chloroplasts induced by an external electrical field.

    PubMed

    de Grooth, B G; van Gorkom, H J; Meiburg, R F

    1980-02-08

    Absorbance changes induced by electrical field pulses were studied in osmotically swollen spinach chloroplasts. The results and their interpretation on the basis of the geometry and electrical properties of the material may be summarized as follows: 1. The spherical vesicles, 'blebs', formed upon dilution of a chloroplast suspension consist of only a single membrane, while part of the thylakoid system remains concentrated in a few patches on its surface. 2. When an electrical field pulse is applied, an up to 3000-fold enhanced field is built up in the membrane, with a time constant of about 20 mus. From this the specific capacitance of the bleb wall was found to be 2 microF . CM-2. 3. The electrical field in the membrane causes several absorbance changes of the photosynthetic pigments with different dependencies on the direction of polarization of the measuring light. Some of these are due to field-induced changes in orientation, in particular of chlorophyll alpha, and have a relaxation time of less than 100 mus. Most of the absorbance changes directly reflect the kinetics of the membrane potential and can be ascribed to electrochromic shifts of photosynthetic pigments, mainly of carotenoids. 4. The carotenoid absorbance changes depend quadratically on the membrane potential; an apparent saturation at high applied field strengths is ascribed to dielectric breakdown at a membrane potential of about 1 V. 5. All carotenoids in the membrane contribute to the absorbance changes induced by an externally applied field, whereas the well-known light-induced electrochromic absorbance change at 518 nm is mainly caused by a minor fraction of permanently polarized and spectrally red-shifted carotenoids. A computer simulation showed that this interpretation quantitatively explains the results and requires no unreasonable values of the various parameters involved.

  20. Testing fractional action cosmology

    NASA Astrophysics Data System (ADS)

    Shchigolev, V. K.

    2016-08-01

    The present work deals with a combined test of the so-called Fractional Action Cosmology (FAC) on the example of a specific model obtained by the author earlier. In this model, the effective cosmological term is proportional to the Hubble parameter squared through the so-called kinematic induction. The reason of studying this cosmological model could be explained by its ability to describe two periods of accelerated expansion, that is in agreement with the recent observations and the cosmological inflation paradigm. First of all, we put our model through the theoretical tests, which gives a general conception of the influence of the model parameters on its behavior. Then, we obtain some restrictions on the principal parameters of the model, including the fractional index, by means of the observational data. Finally, the cosmography parameters and the observational data compared to the theoretical predictions are presented both analytically and graphically.

  1. Fractional lattice charge transport

    PubMed Central

    Flach, Sergej; Khomeriki, Ramaz

    2017-01-01

    We consider the dynamics of noninteracting quantum particles on a square lattice in the presence of a magnetic flux α and a dc electric field E oriented along the lattice diagonal. In general, the adiabatic dynamics will be characterized by Bloch oscillations in the electrical field direction and dispersive ballistic transport in the perpendicular direction. For rational values of α and a corresponding discrete set of values of E(α) vanishing gaps in the spectrum induce a fractionalization of the charge in the perpendicular direction - while left movers are still performing dispersive ballistic transport, the complementary fraction of right movers is propagating in a dispersionless relativistic manner in the opposite direction. Generalizations and the possible probing of the effect with atomic Bose-Einstein condensates and photonic networks are discussed. Zak phase of respective band associated with gap closing regime has been computed and it is found converging to π/2 value. PMID:28102302

  2. Floquet Fractional Chern Insulators

    NASA Astrophysics Data System (ADS)

    Grushin, Adolfo G.; Gómez-León, Álvaro; Neupert, Titus

    2014-04-01

    We show theoretically that periodically driven systems with short range Hubbard interactions offer a feasible platform to experimentally realize fractional Chern insulator states. We exemplify the procedure for both the driven honeycomb and the square lattice, where we derive the effective steady state band structure of the driven system by using the Floquet theory and subsequently study the interacting system with exact numerical diagonalization. The fractional Chern insulator state equivalent to the 1/3 Laughlin state appears at 7/12 total filling (1/6 filling of the upper band). The state also features spontaneous ferromagnetism and is thus an example of the spontaneous breaking of a continuous symmetry along with a topological phase transition. We discuss light-driven graphene and shaken optical lattices as possible experimental systems that can realize such a state.

  3. Fractional Trajectories: Decorrelation Versus Friction

    DTIC Science & Technology

    2013-07-27

    from the integration of fractional differential equations in time. In Section 2 we provide a general demonstration of the new perspective on fractional ...section we demonstrate the equivalence between a fractional trajectory that is the solution of a Caputo fractional differential equation , and the... fractional differential equation dα dtα V(t) = OV(t), (1) where 0 < α < 1 and O is an operator, either linear or nonlinear, acting on the vector V(t

  4. Fractional Galilean symmetries

    NASA Astrophysics Data System (ADS)

    Hosseiny, Ali; Rouhani, Shahin

    2016-09-01

    We generalize the differential representation of the operators of the Galilean algebras to include fractional derivatives. As a result a whole new class of scale invariant Galilean algebras are obtained. The first member of this class has dynamical index z = 2 similar to the Schrödinger algebra. The second member of the class has dynamical index z = 3 / 2, which happens to be the dynamical index Kardar-Parisi-Zhang equation.

  5. New Dry Fractionation Methods

    NASA Technical Reports Server (NTRS)

    McKay, David S.; Cooper, Bonnie L.

    2010-01-01

    This slide presentation describes new fractionation methods that are used to create dust that is respirable for testing the effects of inhalation of lunar dust in preparation for future manned lunar exploration. Because lunar dust is a very limited commodity, a method that does not result in loss of the material had to be developed. The dust separation system that is described incorporates some traditional methods, while preventing the dust from being contaminated or changed in reactivity properties while also limiting losses.

  6. Model Fractional Chern Insulators

    NASA Astrophysics Data System (ADS)

    Behrmann, Jörg; Liu, Zhao; Bergholtz, Emil J.

    2016-05-01

    We devise local lattice models whose ground states are model fractional Chern insulators—Abelian and non-Abelian topologically ordered states characterized by exact ground state degeneracies at any finite size and infinite entanglement gaps. Most saliently, we construct exact parent Hamiltonians for two distinct families of bosonic lattice generalizations of the Zk parafermion quantum Hall states: (i) color-entangled fractional Chern insulators at band filling fractions ν =k /(C +1 ) and (ii) nematic states at ν =k /2 , where C is the Chern number of the lowest band. In spite of a fluctuating Berry curvature, our construction is partially frustration free: the ground states reside entirely within the lowest band and exactly minimize a local (k +1 ) body repulsion term by term. In addition to providing the first known models hosting intriguing states such as higher Chern number generalizations of the Fibonacci anyon quantum Hall states, the remarkable stability and finite-size properties make our models particularly well suited for the study of novel phenomena involving, e.g., twist defects and proximity induced superconductivity, as well as being a guide for designing experiments.

  7. Antioxidant Activity of a Red Lentil Extract and Its Fractions

    PubMed Central

    Amarowicz, Ryszard; Estrella, Isabell; Hernández, Teresa; Dueñas, Montserrat; Troszyńska, Agnieszka; Agnieszka, Kosińska; Pegg, Ronald B.

    2009-01-01

    Phenolic compounds were extracted from red lentil seeds using 80% (v/v) aqueous acetone. The crude extract was applied to a Sephadex LH-20 column. Fraction 1, consisting of sugars and low-molecular-weight phenolics, was eluted from the column by ethanol. Fraction 2, consisting of tannins, was obtained using acetone-water (1:1; v/v) as the mobile phase. Phenolic compounds present in the crude extract and its fractions demonstrated antioxidant and antiradical activities as revealed from studies using a β-carotene-linoleate model system, the total antioxidant activity (TAA) method, the DPPH radical-scavenging activity assay, and a reducing power evaluation. Results of these assays showed the highest values when tannins (fraction 2) were tested. For instance, the TAA of the tannin fraction was 5.85 μmol Trolox® eq./mg, whereas the crude extract and fraction 1 showed 0.68 and 0.33 μmol Trolox® eq./mg, respectively. The content of total phenolics in fraction 2 was the highest (290 mg/g); the tannin content, determined using the vanillin method and expressed as absorbance units at 500 nm per 1 g, was 129. There were 24 compounds identified in the crude extract using an HPLC-ESI-MS method: quercetin diglycoside, catechin, digallate procyanidin, and p-hydroxybenzoic were the dominant phenolics in the extract. PMID:20054484

  8. Modeling the Effect of Polychromatic Light in Quantitative Absorbance Spectroscopy

    ERIC Educational Resources Information Center

    Smith, Rachel; Cantrell, Kevin

    2007-01-01

    Laboratory experiment is conducted to give the students practical experience with the principles of electronic absorbance spectroscopy. This straightforward approach creates a powerful tool for exploring many of the aspects of quantitative absorbance spectroscopy.

  9. Effect of inclusions' distribution on microwave absorbing properties of composites

    NASA Astrophysics Data System (ADS)

    Qin, Siliang; Wang, Qingguo; Qu, Zhaoming

    2013-03-01

    Effect of inclusions' spatial distributions on the permeability and permittivity of composites is studied using the generalized Maxwell-Garnett equations. The result indicates that inclusions' orientation distribution can increase the longitudinal electromagnetic parameters. For inclusions' random and orientation distribution, single and three-layer absorbers are designed and optimized using genetic algorithm. The result shows that under a given absorbing requirement, absorber with inclusions' orientation distribution is lighter and thinner than absorber with inclusions' random distribution.

  10. Method for absorbing an ion from a fluid

    DOEpatents

    Gao, Huizhen; Wang, Yifeng; Bryan, Charles R.

    2007-07-03

    A method for absorbing an ion from a fluid by using dispersing an organic acid into an anion surfactant solution, mixing in a divalent-metal containing compound and a trivalent-metal containing compound and calcining the resulting solid layered double hydroxide product to form an absorbent material and then contacting the absorbent material with an aqueous solution of cations or anions to be absorbed.

  11. Dynamic testing of airplane shock-absorbing struts

    NASA Technical Reports Server (NTRS)

    Langer, P; Thome, W

    1932-01-01

    Measurement of perpendicular impacts of a landing gear with different shock-absorbing struts against the drum testing stand. Tests were made with pneumatic shock absorbers having various degrees of damping, liquid shock absorbers, steel-spring shock absorbers and rigid struts. Falling tests and rolling tests. Maximum impact and gradual reduction of the impacts in number and time in the falling tests. Maximum impact and number of weaker impacts in rolling tests.

  12. An Energy Absorber for the International Space Station

    NASA Technical Reports Server (NTRS)

    Wilkes, Bob; Laurence, Lora

    2000-01-01

    The energy absorber described herein is similar in size and shape to an automotive shock absorber, requiring a constant, high load to compress over the stroke, and self-resetting with a small load. The differences in these loads over the stroke represent the energy absorbed by the device, which is dissipated as friction. This paper describes the evolution of the energy absorber, presents the results of testing performed, and shows the sensitivity of this device to several key design variables.

  13. Unification of X-ray Winds in Seyfert Galaxies: From Ultra-fast Outflows to Warm Absorbers

    NASA Astrophysics Data System (ADS)

    Tombesi, Francesco; Cappi, M.; Reeves, J.; Nemmen, R.; Braito, V.; Gaspari, M.; Reynolds, C. S.

    2013-04-01

    The existence of ionized X-ray absorbing layers of gas along the line of sight to the nuclei of Seyfert galaxies is a well established observational fact. This material is systematically outflowing and shows a large range in parameters. However, its actual nature and dynamics are still not clear. In order to gain insights into these important issues we performed a literature search for papers reporting the parameters of the soft X-ray warm absorbers (WAs) in 35 type 1 Seyferts and compared their properties to those of the ultra-fast outflows (UFOs) detected in the same sample. The fraction of sources with WAs is >60%, consistent with previous studies. The fraction of sources with UFOs is >34%, >67% of which also show WAs. The large dynamic range obtained when considering all the absorbers together allows us, for the first time, to investigate general relations among them. In particular, we find significant correlations indicating that the closer the absorber is to the central black hole, the higher the ionization, column, outflow velocity and consequently the mechanical power. The absorbers continuously populate the whole parameter space, with the WAs and the UFOs lying always at the two ends of the distribution. This strongly suggest that these absorbers, often considered of different types, could actually represent parts of a single large-scale stratified outflow observed at different locations from the black hole. The observed parameters and correlations are consistent with both radiation pressure through Compton scattering and MHD processes contributing to the outflow acceleration, the latter playing a major role. Most of the absorbers, especially the UFOs, have a sufficiently high mechanical power to significantly contribute to the AGN feedback.

  14. Characterization of absorbing aerosol types using ground and satellites based observations over an urban environment

    NASA Astrophysics Data System (ADS)

    Bibi, Samina; Alam, Khan; Chishtie, Farrukh; Bibi, Humera

    2017-02-01

    In this paper, for the first time, an effort has been made to seasonally characterize the absorbing aerosols into different types using ground and satellite based observations. For this purpose, optical properties of aerosol retrieved from AErosol RObotic NETwork (AERONET) and Ozone Monitoring Instrument (OMI) were utilized over Karachi for the period 2012 to 2014. Firstly, OMI AODabs was validated with AERONET AODabs and found to have a high degree of correlation. Then, based on this validation, characterization was conducted by analyzing aerosol Fine Mode Fraction (FMF), Angstrom Exponent (AE), Absorption Angstrom Exponent (AAE), Single Scattering Albedo (SSA) and Aerosol Index (AI) and their mutual correlation, to identify the absorbing aerosol types and also to examine the variability in seasonal distribution. The absorbing aerosols were characterized into Mostly Black Carbon (BC), Mostly Dust and Mixed BC & Dust. The results revealed that Mostly BC aerosols contributed dominantly during winter and postmonsoon whereas, Mostly Dust were dominant during summer and premonsoon. These types of absorbing aerosol were also confirmed with MODerate resolution Imaging Spectroradiometer (MODIS) and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) observations.

  15. The X-ray Absorber in the X-ray Transient NLS1 WPVS 007

    NASA Astrophysics Data System (ADS)

    Grupe, Dirk

    This proposal is for a funding request for an approved XMM-Newton observations of the X-ray transient Narrow-Line Seyfert 1 galaxy WPVS 007. The request is for 4 month of salary for the PI for one year in order to do the data analysis, publish the results, and attend an international AGN meeting. XMM will observe WPVS 007 in June 2010 simultaneously with HST, Chandra, and Swift. The goal is to establish a tight connection between the UV broad absorption line troughs found in FUSE observations and the strong partial covering absorber feature found by Swift. WPVS 007 showed a dramatic transformation into a Broad Absorption line QSO like AGN between a 1996 HST observation and a 2003 FUSE observation. Several Swift monitoring observations have suggested that the absorber may have started to disappear. Therefore it is crucial for our HST COS UV spectroscopy to know what the status of the X-ray absorber is. The XMM observation will provide a well-exposed X-ray spectrum even if WPVS 007 will be in a low flux state. This spectrum will enable us to put constraints on the absorption column density and covering fraction of the partial covering absorber.

  16. Exploring Light’s Interactions with Bubbles and Light Absorbers in Photoelectrochemical Devices using Ray Tracing

    SciTech Connect

    Stevens, John Colby

    2012-12-01

    Ray tracing was used to perform optical optimization of arrays of photovoltaic microrods and explore the interaction between light and bubbles of oxygen gas on the surface of the microrods. The incident angle of light was varied over a wide range. The percent of incident light absorbed by the microrods and reflected by the bubbles was computed over this range. It was found that, for the 10 μm diameter, 100 μm tall SrTiO3 microrods simulated in the model, the optimal center-­to-­center spacing was 14 μm for a square grid. This geometry produced 75% average and 90% maximum absorbance. For a triangular grid using the same microrods, the optimal center-­to-­center spacing was 14 μm. This geometry produced 67% average and 85% maximum absorbance. For a randomly laid out grid of 5 μm diameter, 100 μm tall SrTiO3 microrods with an average center-­to-­center spacing of 20 μm, the average absorption was 23% and the maximum absorption was 43%. For a 50% areal coverage fraction of bubbles on the absorber surface, between 2%-­20% of the incident light energy was reflected away from the rods by the bubbles, depending upon incident angle and bubble morphology.

  17. 40 CFR 65.150 - Absorbers used as control devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 16 2014-07-01 2014-07-01 false Absorbers used as control devices. 65... (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Closed Vent Systems, Control Devices, and Routing to a Fuel Gas System or a Process § 65.150 Absorbers used as control devices. (a) Absorber equipment and...

  18. Graphene metamaterials based tunable terahertz absorber: effective surface conductivity approach.

    PubMed

    Andryieuski, Andrei; Lavrinenko, Andrei V

    2013-04-08

    In this paper we present the efficient design of functional thin-film metamaterial devices with the effective surface conductivity approach. As an example, we demonstrate a graphene based perfect absorber. After formulating the requirements to the perfect absorber in terms of surface conductivity we investigate the properties of graphene wire medium and graphene fishnet metamaterials and demonstrate both narrowband and broadband tunable absorbers.

  19. About sound mufflers sound-absorbing panels aircraft engine

    NASA Astrophysics Data System (ADS)

    Dudarev, A. S.; Bulbovich, R. V.; Svirshchev, V. I.

    2016-10-01

    The article provides a formula for calculating the frequency of sound absorbed panel with a perforated wall. And although the sound absorbing structure is a set of resonators Helmholtz, not individual resonators should be considered in acoustic calculations, and all the perforated wall panel. The analysis, showing how the parameters affect the size and sound-absorbing structures in the absorption rate.

  20. 21 CFR 880.5300 - Medical absorbent fiber.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical absorbent fiber. 880.5300 Section 880.5300... Devices § 880.5300 Medical absorbent fiber. (a) Identification. A medical absorbent fiber is a device intended for medical purposes that is made from cotton or synthetic fiber in the shape of a ball or a...

  1. 14 CFR 29.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Tires and shock absorbers. 29.475 Section... shock absorbers. Unless otherwise prescribed, for each specified landing condition, the tires must be assumed to be in their static position and the shock absorbers to be in their most critical position....

  2. 14 CFR 29.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Tires and shock absorbers. 29.475 Section... shock absorbers. Unless otherwise prescribed, for each specified landing condition, the tires must be assumed to be in their static position and the shock absorbers to be in their most critical position....

  3. 14 CFR 29.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Tires and shock absorbers. 29.475 Section... shock absorbers. Unless otherwise prescribed, for each specified landing condition, the tires must be assumed to be in their static position and the shock absorbers to be in their most critical position....

  4. 14 CFR 29.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Tires and shock absorbers. 29.475 Section... shock absorbers. Unless otherwise prescribed, for each specified landing condition, the tires must be assumed to be in their static position and the shock absorbers to be in their most critical position....

  5. 14 CFR 29.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Tires and shock absorbers. 29.475 Section... shock absorbers. Unless otherwise prescribed, for each specified landing condition, the tires must be assumed to be in their static position and the shock absorbers to be in their most critical position....

  6. 21 CFR 868.5300 - Carbon dioxide absorbent.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Carbon dioxide absorbent. 868.5300 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5300 Carbon dioxide absorbent. (a) Identification. A carbon dioxide absorbent is a device intended for medical purposes that consists of...

  7. 21 CFR 868.5310 - Carbon dioxide absorber.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Carbon dioxide absorber. 868.5310 Section 868.5310...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5310 Carbon dioxide absorber. (a) Identification. A carbon dioxide absorber is a device that is intended for medical purposes and that is used in...

  8. 21 CFR 868.5300 - Carbon dioxide absorbent.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Carbon dioxide absorbent. 868.5300 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5300 Carbon dioxide absorbent. (a) Identification. A carbon dioxide absorbent is a device intended for medical purposes that consists of...

  9. 21 CFR 868.5300 - Carbon dioxide absorbent.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Carbon dioxide absorbent. 868.5300 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5300 Carbon dioxide absorbent. (a) Identification. A carbon dioxide absorbent is a device intended for medical purposes that consists of...

  10. 21 CFR 868.5310 - Carbon dioxide absorber.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Carbon dioxide absorber. 868.5310 Section 868.5310...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5310 Carbon dioxide absorber. (a) Identification. A carbon dioxide absorber is a device that is intended for medical purposes and that is used in...

  11. 21 CFR 868.5310 - Carbon dioxide absorber.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Carbon dioxide absorber. 868.5310 Section 868.5310...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5310 Carbon dioxide absorber. (a) Identification. A carbon dioxide absorber is a device that is intended for medical purposes and that is used in...

  12. 21 CFR 868.5310 - Carbon dioxide absorber.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Carbon dioxide absorber. 868.5310 Section 868.5310...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5310 Carbon dioxide absorber. (a) Identification. A carbon dioxide absorber is a device that is intended for medical purposes and that is used in...

  13. 21 CFR 868.5300 - Carbon dioxide absorbent.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Carbon dioxide absorbent. 868.5300 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5300 Carbon dioxide absorbent. (a) Identification. A carbon dioxide absorbent is a device intended for medical purposes that consists of...

  14. 21 CFR 868.5300 - Carbon dioxide absorbent.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Carbon dioxide absorbent. 868.5300 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5300 Carbon dioxide absorbent. (a) Identification. A carbon dioxide absorbent is a device intended for medical purposes that consists of...

  15. 21 CFR 868.5310 - Carbon dioxide absorber.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Carbon dioxide absorber. 868.5310 Section 868.5310...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5310 Carbon dioxide absorber. (a) Identification. A carbon dioxide absorber is a device that is intended for medical purposes and that is used in...

  16. 21 CFR 878.4755 - Absorbable lung biopsy plug.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Absorbable lung biopsy plug. 878.4755 Section 878...) MEDICAL DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4755 Absorbable lung biopsy plug. (a) Identification. A preformed (polymerized) absorbable lung biopsy plug is intended to...

  17. [Absorbable coronary stents. New promising technology].

    PubMed

    Erbel, Raimund; Böse, Dirk; Haude, Michael; Kordish, Igor; Churzidze, Sofia; Malyar, Nasser; Konorza, Thomas; Sack, Stefan

    2007-06-01

    Coronary stent implantation started in Germany 20 years ago. In the beginning, the progress was very slow and accelerated 10 years later. Meanwhile, coronary stent implantation is a standard procedure in interventional cardiology. From the beginning of permanent stent implantation, research started to provide temporary stenting of coronary arteries, first with catheter-based systems, later with stent-alone technology. Stents were produced from polymers or metal. The first polymer stent implantation failed except the Igaki-Tamai stent in Japan. Newly developed absorbable polymer stents seem to be very promising, as intravascular ultrasound (IVUS) and optical coherence tomography have demonstrated. Temporary metal stents were developed based on iron and magnesium. Currently, the iron stent is tested in peripheral arteries. The absorbable magnesium stent (Biotronik, Berlin, Germany) was tested in peripheral arteries below the knee and meanwhile in the multicenter international PROGRESS-AMS (Clinical Performance and Angiographic Results of Coronary Stenting with Absorbable Metal Stents) study. The first magnesium stent implantation was performed on July 30, 2004 after extended experimental testing in Essen. The magnesium stent behaved like a bare-metal stent with low recoil of 5-7%. The stent struts were absorbed when tested with IVUS. Stent struts were not visible by fluoroscopy or computed tomography (CT) as well as magnetic resonance imaging (MRI). That means, that the magnesium stent is invisible and therefore CT and MRI can be used for imaging of interventions. Only using micro-CT the stent struts were visible. The absorption process could be demonstrated in a patient 18 days after implantation due to suspected acute coronary syndrome, which was excluded. IVUS showed a nice open lumen. Stent struts were no longer visible, but replaced by tissue indicating the previous stent location. Coronary angiography after 4 months showed an ischemia-driven target lesion

  18. [Performance of desulfurizing absorbent of roasted navajoite].

    PubMed

    Chen, Fang; Yang, Chun-ping; Gan, Hai-ming; Wu, Ting; Chen, Hai-lin; Chen, Hong; Xu, Ke-hui; Xie, Geng-xin

    2010-04-01

    An innovative flue gas desulfurization (FGD) coupling process was proposed in this study to overcome the problems in wet-type limestone/lime processes which include fouling, clogging, and difficulty of selling the by-products and the problems in traditional process for vanadium extraction from navajoite ore such as excessive consumption of sulfuric acid and emissions of pollutants. The performance of a jet bubbling reactor (JBR) at pilot-scale was evaluated using navajoite ore produced in the process of extracting vanadium pentoxide as desulfurization absorbent. Results showed that navajoite ore slurry achieved better desulfurization performance than limestone slurry. When the inlet flue gas pressure drop was 3.0 kPa, the gas flow was about 2350 m3 x h(-1) and the pH of the navajoite ore slurry was higher than 4.5, the desulfurization efficiency was stable about 90%. The SO2 removal efficiency appeared to increase along with the increasing of absorbent cycle-index. The efficiency of the second circulation was improved 3.5% compared to the first circulation. After an operating duration of 40 minutes, the leaching rate of vanadium pentoxide was about 20%, and reached 60% when the by-products were leached with 5% dilute sulfuric acid for 10 hours. The by-product from this process not only could be used to produce vanadium pentoxide which is a valuable industrial product, but also could significantly overcome the pollution problem existing in the traditional refining process of vanadium pentoxide when navajoite ore is used as the feed material. This FGD process using roasted navajoite slurry as absorbent is environmental sound and cost-effective, and shows the potential for application in the field of flue gas desulfurization as well as hydrometallurgy.

  19. Exposure testing of solar absorber surfaces

    SciTech Connect

    Moore, S.W.

    1986-01-01

    The Los Alamos National Laboratory has been involved in supporting, monitoring and conducting exposure testing of solar materials for approximately ten years. The Laboratory has provided technical monitoring of the IITRI, DSET, Lockheed, and Berry contracts and has operated the Los Alamos exposure Facility for over five years. This report will outline some of the past exposure testing, the testing still in progress, and describe some of the major findings. While this report will primarily emphasize solar absorber surfaces, some of the significant findings relative to advanced glazing will be discussed.

  20. Ultra-broadband microwave metamaterial absorber

    NASA Astrophysics Data System (ADS)

    Ding, Fei; Cui, Yanxia; Ge, Xiaochen; Jin, Yi; He, Sailing

    2012-03-01

    A microwave ultra-broadband polarization-independent metamaterial absorber is demonstrated. It is composed of a periodic array of metal-dielectric multilayered quadrangular frustum pyramids. These pyramids possess resonant absorption modes at multi-frequencies, of which the overlapping leads to the total absorption of the incident wave over an ultra-wide spectral band. The experimental absorption at normal incidence is above 90% in the frequency range of 7.8-14.7 GHz, and the absorption is kept large when the incident angle is smaller than 60°. The experimental results agree well with the numerical simulation.

  1. Electrically tunable absorber based on nonstructured graphene

    NASA Astrophysics Data System (ADS)

    Ye, Caiyan; Zhu, Zhihong; Xu, Wei; Yuan, Xiaodong; Qin, Shiqiao

    2015-12-01

    We demonstrate numerically that a tunable absorber with absorption of 99.94% in the far infrared range can be obtained using a nonstructured graphene. The mechanism originates from a nonstructured graphene film supported on a periodical dielectric array that can show Fermi level modulation periodically and produce plasmonic resonances in the far infrared range. The nonstructured graphene can avoid the unexpected edge effects and does not influence the unique properties of graphene, which will be helpful in practice to achieve the unity absorption and facilitate the development of many related applications.

  2. An electromechanical low frequency panel sound absorber.

    PubMed

    Chang, Daoqing; Liu, Bilong; Li, Xiaodong

    2010-08-01

    The sound absorbing properties of a thin micro-perforated plate (MPP) coated with piezoelectric material with shunt damping technology is investigated. First a theoretical model is presented to predict the sound absorption coefficients of a thin plate attached with a piezoelectric patch and electrical circuits. Then the model is extended to analyze the sound absorption for a thin plate with micro perforations and piezoelectric material. Measurements are also carried out in an impedance tube and found to be in good agreements with the theoretical model. The sound absorption of the constructions can be much improved by tuning the electrical circuits.

  3. Piston-rotaxanes as molecular shock absorbers.

    PubMed

    Sevick, E M; Williams, D R M

    2010-04-20

    We describe the thermomechanical response of a new molecular system that behaves as a shock absorber. The system consists of a rodlike rotaxane connected to a piston and tethered to a surface. The response of this system is dominated by the translational entropy of the rotaxane rings and can be calculated exactly. The force laws are contrasted with those for a rigid rod and a polymer. In some cases, the rotaxanes undergo a sudden transition to a tilted state when compressed. These piston-rotaxanes provide a potential motif for the design of a new class of materials with a novel thermomechanical response.

  4. DHCAL with minimal absorber: measurements with positrons

    NASA Astrophysics Data System (ADS)

    Freund, B.; Neubüser, C.; Repond, J.; Schlereth, J.; Xia, L.; Dotti, A.; Grefe, C.; Ivantchenko, V.; Berenguer Antequera, J.; Calvo Alamillo, E.; Fouz, M.-C.; Marin, J.; Puerta-Pelayo, J.; Verdugo, A.; Brianne, E.; Ebrahimi, A.; Gadow, K.; Göttlicher, P.; Günter, C.; Hartbrich, O.; Hermberg, B.; Irles, A.; Krivan, F.; Krüger, K.; Kvasnicka, J.; Lu, S.; Lutz, B.; Morgunov, V.; Provenza, A.; Reinecke, M.; Sefkow, F.; Schuwalow, S.; Tran, H. L.; Garutti, E.; Laurien, S.; Matysek, M.; Ramilli, M.; Schroeder, S.; Bilki, B.; Norbeck, E.; Northacker, D.; Onel, Y.; Cvach, J.; Gallus, P.; Havranek, M.; Janata, M.; Kovalcuk, M.; Kvasnicka, J.; Lednicky, D.; Marcisovsky, M.; Polak, I.; Popule, J.; Tomasek, L.; Tomasek, M.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; van Doren, B.; Wilson, G. W.; Kawagoe, K.; Hirai, H.; Sudo, Y.; Suehara, T.; Sumida, H.; Takada, S.; Tomita, T.; Yoshioka, T.; Bilokin, S.; Bonis, J.; Cornebise, P.; Pöschl, R.; Richard, F.; Thiebault, A.; Zerwas, D.; Hostachy, J.-Y.; Morin, L.; Besson, D.; Chadeeva, M.; Danilov, M.; Markin, O.; Popova, E.; Gabriel, M.; Goecke, P.; Kiesling, C.; van der Kolk, N.; Simon, F.; Szalay, M.; Corriveau, F.; Blazey, G. C.; Dyshkant, A.; Francis, K.; Zutshi, V.; Kotera, K.; Ono, H.; Takeshita, T.; Ieki, S.; Kamiya, Y.; Ootani, W.; Shibata, N.; Jeans, D.; Komamiya, S.; Nakanishi, H.

    2016-05-01

    In special tests, the active layers of the CALICE Digital Hadron Calorimeter prototype, the DHCAL, were exposed to low energy particle beams, without being interleaved by absorber plates. The thickness of each layer corresponded approximately to 0.29 radiation lengths or 0.034 nuclear interaction lengths, defined mostly by the copper and steel skins of the detector cassettes. This paper reports on measurements performed with this device in the Fermilab test beam with positrons in the energy range of 1 to 10 GeV. The measurements are compared to simulations based on GEANT4 and a standalone program to emulate the detailed response of the active elements.

  5. Absorbing boundary conditions for exterior problems

    NASA Technical Reports Server (NTRS)

    Hariharan, S. I.

    1985-01-01

    Elliptic and hyperbolic problems in unbounded regions are considered. These problems, when one wants to solve them numerically, have the difficulty of prescribing boundary conditions at infinity. Computationally, one needs a finite region in which to solve these problems. The corresponding conditions at infinity imposed on the finite distance boundaries should dictate the boundary condition at infinity and be accurate with respect to the interior numerical scheme. Such boundary conditions are commonly referred to as absorbing boundary conditions. A treatment is given of these boundary conditions for wave-like equations.

  6. Highly absorbing ARC for DUV lithography

    NASA Astrophysics Data System (ADS)

    Pavelchek, Edward K.; Meador, James D.; Guerrero, Douglas J.; Lamb, James E., III; Kache, Ajit; doCanto, Manuel; Adams, Timothy G.; Stark, David R.; Miller, Daniel A.

    1996-06-01

    The properties of a new anti-reflective coating for 248 nm lithography are described. It is formed by thermally cross-linking a spin-on organic coating, and has an absorbance greater than 12/micrometers. It is compatible with UVIIHS and APEX-E photoresists. Thin films (less than 600 angstrom over silicon substrates) are found to completely suppress standing waves, to reduce EO swing curves to less than 3%, and to offer good CD control over typical field oxide topography. The etch rate was found to be comparable to that of the APEX-E photoresist.

  7. A novel broadband waterborne acoustic absorber

    NASA Astrophysics Data System (ADS)

    Wang, Changxian; Wen, Weibin; Huang, Yixing; Chen, Mingji; Lei, Hongshuai; Fang, Daining

    2016-07-01

    In this paper, we extended the ray tracing theory in polar coordinate system, and originally proposed the Snell-Descartes law in polar coordinates. Based on these theories, a novel broadband waterborne acoustic absorber device was proposed. This device is designed with gradient-distributing materials along radius, which makes the incidence acoustic wave ray warps. The echo reduction effects of this device were investigated by finite element analysis, and the numerical results show that the reflectivity of acoustic wave for the new device is lower than that of homogenous and Alberich layers in almost all frequency 0-30 kHz at the same loss factor.

  8. [Ablative and fractional lasers].

    PubMed

    Beylot, C; Grognard, C; Michaud, T

    2009-10-01

    The use of pulsed or scanning Carbon Dioxide, and pulsed Erbium-YAG lasers allows the programmable and reproducible photocoagulation of thin layers of the epidermis and superficial dermis. Thermal damage depends on the type of laser and is greater with CO(2) lasers. The degree of neocollagenesis is proportional to the thermal damage and is better with CO(2) lasers. Their main indication is the correction of photoaged facial skin but they can also be used for corrective dermatology, e.g. for scars and genodermatosis. Results are highly satisfactory but the technique is invasive and the patient experiences a social hindrance of around two weeks. Fractionated techniques treat 25% of the defective skin area at each session in noncontiguous microzones; four sessions are therefore necessary to treat the entire cutaneous surface. The treatment is given under topical anesthesia and is much less invasive, particularly with nonablative fractional laser treatment in which photothermolysis does not penetrate below the epidermis and/or the effects are slight, with no or very little social isolation. However, the results are much less satisfactory than the results of ablative laser and there is no firming effect. Other zones than the face can be treated. With the fractional CO(2) and Erbium ablative lasers, which have multiplied over the past 2 years, the much wider impacts cause perforation of the epidermis and there is a zone of ablation by laser photovaporization, with a zone of thermal damage below. The results are better in correcting photoaging of the face, without, however, achieving the efficacy of ablative lasers, which remain the reference technique. However, the effects are not insignificant, requiring at least 5 days of social isolation.

  9. Traffic model with an absorbing-state phase transition

    NASA Astrophysics Data System (ADS)

    Iannini, M. L. L.; Dickman, Ronald

    2017-02-01

    We consider a modified Nagel-Schreckenberg (NS) model in which drivers do not decelerate if their speed is smaller than the headway (number of empty sites to the car ahead). (In the original NS model, such a reduction in speed occurs with probability p , independent of the headway, as long as the current speed is greater than zero.) In the modified model the free-flow state (with all vehicles traveling at the maximum speed, vmax) is absorbing for densities ρ smaller than a critical value ρc=1 /(vmax+2 ) . The phase diagram in the ρ -p plane is reentrant: for densities in the range ρc ,<<ρ <ρc , both small and large values of p favor free flow, while for intermediate values, a nonzero fraction of vehicles have speeds

  10. Fractional channel multichannel analyzer

    DOEpatents

    Brackenbush, Larry W.; Anderson, Gordon A.

    1994-01-01

    A multichannel analyzer incorporating the features of the present invention obtains the effect of fractional channels thus greatly reducing the number of actual channels necessary to record complex line spectra. This is accomplished by using an analog-to-digital converter in the asynscronous mode, i.e., the gate pulse from the pulse height-to-pulse width converter is not synchronized with the signal from a clock oscillator. This saves power and reduces the number of components required on the board to achieve the effect of radically expanding the number of channels without changing the circuit board.

  11. Fractional channel multichannel analyzer

    DOEpatents

    Brackenbush, L.W.; Anderson, G.A.

    1994-08-23

    A multichannel analyzer incorporating the features of the present invention obtains the effect of fractional channels thus greatly reducing the number of actual channels necessary to record complex line spectra. This is accomplished by using an analog-to-digital converter in the asynchronous mode, i.e., the gate pulse from the pulse height-to-pulse width converter is not synchronized with the signal from a clock oscillator. This saves power and reduces the number of components required on the board to achieve the effect of radically expanding the number of channels without changing the circuit board. 9 figs.

  12. Solvent Fractionation of Lignin

    SciTech Connect

    Chatterjee, Sabornie; Saito, Tomonori

    2014-01-01

    Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. The major issues for the commercial production of value added high performance lignin products are lignin s physical and chemical heterogenities. To overcome these problems, a variety of procedures have been developed to produce pure lignin suitable for high performace applications such as lignin-derived carbon materials. However, most of the isolation procedures affect lignin s properties and structure. In this chapter, a short review of the effect of solvent fractionation on lignin s properties and structure is presented.

  13. Insight into the Nonlinear Absorbance of Two Related Series of Two-Photon Absorbing Chromophores (Postprint)

    DTIC Science & Technology

    2007-01-01

    Reinhardt, B. A. Opt. Lett. 1995, 20, 1524. (f) Larson, E . J.; Friesen , L. A.; Johnson, C. K. Chem. Phys. Lett. 1997, 265, 161. (g) Albota, M.; Beljonne, D...62102F 5d. PROJECT NUMBER 4348 5e. TASK NUMBER RG 6. AUTHOR(S) Joy E . Rogers (UES, Inc.) Jonathan E . Slagle (AT&T Government Solutions) Daniel G...Insight into the Nonlinear Absorbance of Two Related Series of Two-Photon Absorbing Chromophores Joy E . Rogers,*,†,‡ Jonathan E . Slagle,†,§ Daniel G

  14. Body Fractions: A Physical Approach to Fraction Learning

    ERIC Educational Resources Information Center

    Mills, Judith

    2011-01-01

    Many students experience great difficulty understanding the meaning of fractions. For many students who have spent their early mathematics lessons focusing on counting (whole) numbers, recognising that there are many numbers between those whole numbers called fractional numbers, is quite revolutionary. The foundation of understanding fractions is…

  15. Voltage-dependent absorbance change of carotenoids in halophilic archaebacteria.

    PubMed

    Seki, S I; Sasabe, H; Tomioka, H

    1996-10-02

    Membrane vesicles of wild-type Halobacterium sp. mex strain show a wavy absorbance change which has not been so far reported in halophilic archaebacteria. A white mutant strain lacking carotenoids did not show the wavy absorbance change. The wavy absorbance change in the range of 440-590 nm was induced by a red flash (600-640 nm), which photoexcited electrogenic ion pumps, mex bacteriorhodopsin and mex halorhodopsin but not carotenoids. The wavy change was also caused by K+ diffusion potentials without light. These results suggest that the wavy absorbance change in the membrane vesicles is the voltage-dependent absorbance change of the carotenoids.

  16. Depth distribution of absorbed dose on the external surface of Cosmos 1887 biosatellite

    SciTech Connect

    Watts, J.W. Jr.; Parnell, T.A.; Akatov, Yu.A.; Dudkin, V.E.; Kovalev, E.E.; Benton, E.V.; Frank, A.L. |

    1995-03-01

    Significant absorbed dose levels exceeding 1.0 Gy day(exp {minus}1) have been measured on the external surface of the Cosmos 1887 biosatellite as functions of depth in stacks of thin thermoluminescent detectors (TLD`s) made in U.S.S.R. and U.S.A. The dose was found to decrease rapidly with increasing absorber thickness, thereby indicating the presence of intensive fluxes of low-energy particles. Comparison between the U.S.S.R. and U.S.A. results and calculations based on the Vette Model environment are in satisfactory agreement. The major contribution to the dose under thin shielding thickness is shown to be from electrons. The fraction of the dose due to protons and heavier charged particles increases with shielding thickness.

  17. Depth distribution of absorbed dose on the external surface of Cosmos 1887 biosatellite

    NASA Technical Reports Server (NTRS)

    Watts, J. W., Jr.; Parnell, T. A.; Akatov, Yu. A.; Dudkin, V. E.; Kovalev, E. E.; Benton, E. V.; Frank, A. L.

    1995-01-01

    Significant absorbed dose levels exceeding 1.0 Gy day(exp -1) have been measured on the external surface of the Cosmos 1887 biosatellite as functions of depth in stacks of thin thermoluminescent detectors (TLD's) made in U.S.S.R. and U.S.A. The dose was found to decrease rapidly with increasing absorber thickness, thereby indicating the presence of intensive fluxes of low-energy particles. Comparison between the U.S.S.R. and U.S.A. results and calculations based on the Vette Model environment are in satisfactory agreement. The major contribution to the dose under thin shielding thickness is shown to be from electrons. The fraction of the dose due to protons and heavier charged particles increases with shielding thickness.

  18. Mapping liquid distribution in absorbent incontinence products.

    PubMed

    Landeryou, M A; Yerworth, R J; Cottenden, A M

    2003-01-01

    This paper reviews methods available for mapping the distribution of fluid in incontinence pad materials to assist with evaluating existing products and developing new ones, and to provide data for building and validating predictive models. Specifically, the following technologies are considered and their strengths and limitations described: discrete sensors based on conductance, temperature or optical measurements, optical imaging, gravimetric methods, X-ray imaging and magnetic resonance imaging. It is suggested that the ideal method would enable fluid distribution to be mapped in three dimensions with good spatial and time resolution in single materials and composite structures of simple and complex geometries under static and dynamic mechanical loading. It would also allow liquid to be mapped in products when worn by users. It is concluded that, although each existing method meets some of these requirements, and each requirement is met, at least reasonably well, by at least one method, improved techniques are needed. The particular need for methods that can provide some measurement of liquid saturation within absorbent products, both in the laboratory and in real use, is highlighted. In many cases, simple methods used appropriately are sufficient to elicit the important aspects of liquid transport and storage within absorbent products.

  19. Configurable metamaterial absorber with pseudo wideband spectrum.

    PubMed

    Zhu, Weiren; Huang, Yongjun; Rukhlenko, Ivan D; Wen, Guangjun; Premaratne, Malin

    2012-03-12

    Metamaterials attain their behavior due to resonant interactions among their subwavelength components and thus show specific designer features only in a very narrow frequency band. There is no simple way to dynamically increase the operating bandwidth of a narrowband metamaterial, but it may be possible to change its central frequency, shifting the spectral response to a new frequency range. In this paper, we propose and experimentally demonstrate a metamaterial absorber that can shift its central operating frequency by using mechanical means. The shift is achieved by varying the gap between the metamaterial and an auxiliary dielectric slab parallel to its surface. We also show that it is possible to create multiple absorption peaks by adjusting the size and/or shape of the dielectric slab, and to shift them by moving the slab relative to the metamaterial. Specifically, using numerical simulations we design a microwave metamaterial absorber and experimentally demonstrate that its central frequency can be set anywhere in a 1.6 GHz frequency range. The proposed configuration is simple and easy to make, and may be readily extended to THz frequencies.

  20. Wave based optimization of distributed vibration absorbers

    NASA Astrophysics Data System (ADS)

    Johnson, Marty; Batton, Brad

    2005-09-01

    The concept of distributed vibration absorbers or DVAs has been investigated in recent years as a method of vibration control and sound radiation control for large flexible structures. These devices are comprised of a distributed compliant layer with a distributed mass layer. When such a device is placed onto a structure it forms a sandwich panel configuration with a very soft core. With this configuration the main effect of the DVA is to create forces normal to the surface of the structure and can be used at low frequencies to either add damping, where constrain layer damper treatments are not very effective, or to pin the structure over a narrow frequency bandwidth (i.e., large input impedance/vibration absorber approach). This paper analyses the behavior of these devices using a wave based approach and finds an optimal damping level for the control of broadband disturbances in panels. The optimal design is calculated by solving the differential equations for waves propagating in coupled plates. It is shown that the optimal damping calculated using the infinite case acts as a good ``rule of thumb'' for designing DVAs to control the vibration of finite panels. This is bourn out in both numerical simulations and experiments.

  1. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Hodgson, Ed; Izenson, Mike; Chan, Weibo; Bue, Grant C.

    2012-01-01

    For decades advanced spacesuit developers have pursued a regenerable, robust nonventing system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA s Spacesuit Water Membrane Evaporator (SWME), and Creare s Lithium Chloride Absorber Radiator (LCAR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. This water vapor is then captured by solid LiCl in the LCAR with a high enthalpy of absorption, resulting in sufficient temperature lift to reject heat to space by radiation. After the sortie, the LCAR would be heated up and dried in a regenerator to drive off and recover the absorbed evaporant. A engineering development prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The LCAR was able to stably reject 75 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.

  2. Possible Quantum Absorber Effects in Cortical Synchronization

    NASA Astrophysics Data System (ADS)

    Kämpf, Uwe

    The Wheeler-Feynman transactional "absorber" approach was proposed originally to account for anomalous resonance coupling between spatio-temporally distant measurement partners in entangled quantum states of so-called Einstein-Podolsky-Rosen paradoxes, e.g. of spatio-temporal non-locality, quantum teleportation, etc. Applied to quantum brain dynamics, however, this view provides an anticipative resonance coupling model for aspects of cortical synchronization and recurrent visual action control. It is proposed to consider the registered activation patterns of neuronal loops in so-called synfire chains not as a result of retarded brain communication processes, but rather as surface effects of a system of standing waves generated in the depth of visual processing. According to this view, they arise from a counterbalance between the actual input's delayed bottom-up data streams and top-down recurrent information-processing of advanced anticipative signals in a Wheeler-Feynman-type absorber mode. In the framework of a "time-loop" model, findings about mirror neurons in the brain cortex are suggested to be at least partially associated with temporal rather than spatial mirror functions of visual processing, similar to phase conjugate adaptive resonance-coupling in nonlinear optics.

  3. Fabrication of THz Sensor with Metamaterial Absorber

    NASA Astrophysics Data System (ADS)

    Gonzalez, Hugo; Alves, Fabio; Karunasiri, Gamani

    The terahertz (THz) portion of the electromagnetic spectrum (0.1-10 THz) has not been fully utilized due to the lack of sensitive detectors. Real-time imaging in this spectral range has been demonstrated using uncooled infrared microbolometer cameras and external illumination provided by quantum cascade laser (QCL) based THz sources. However, the microbolometer pixels in the cameras have not been optimized to achieve high sensitivity in THz frequencies. Recently, we have developed a highly sensitive micromechanical THz sensor employing bi-material effect with an integrated metamaterial absorber tuned to the THz frequency of interest. The use of bi-material structures causes deflection on the sensor to as the absorbed THz radiation increases its temperature, which can be monitored optically by reflecting a light beam. This approach eliminates the integration of readout electronics needed in microbolometers. The absorption of THz by metamaterial can be tailored by controlling geometrical parameters. The sensors can be fabricated using conventional microelectronic materials and incorporated into pixels to form focal plane arrays (FPAs). In this presentation, characterization and readout of a THz sensor with integrated metamaterial structure will be described. Supported by DoD.

  4. Wave energy extraction by coupled resonant absorbers.

    PubMed

    Evans, D V; Porter, R

    2012-01-28

    In this article, a range of problems and theories will be introduced that will build towards a new wave energy converter (WEC) concept, with the acronym 'ROTA' standing for resonant over-topping absorber. First, classical results for wave power absorption for WECs constrained to operate in a single degree of freedom will be reviewed and the role of resonance in their operation highlighted. Emphasis will then be placed on how the introduction of further resonances can improve power take-off characteristics by extending the range of frequencies over which the efficiency is close to a theoretical maximum. Methods for doing this in different types of WECs will be demonstrated. Coupled resonant absorbers achieve this by connecting a WEC device equipped with its own resonance (determined from a hydrodynamic analysis) to a new system having separate mass/spring/damper characteristics. It is shown that a coupled resonant effect can be realized by inserting a water tank into a WEC, and this idea forms the basis of the ROTA device. In essence, the idea is to exploit the coupling between the natural sloshing frequencies of the water in the internal tank and the natural resonance of a submerged buoyant circular cylinder device that is tethered to the sea floor, allowing a rotary motion about its axis of attachment.

  5. Erbium concentration dependent absorbance in tellurite glass

    SciTech Connect

    Sazali, E. S. Rohani, M. S. Sahar, M. R. Arifin, R. Ghoshal, S. K. Hamzah, K.

    2014-09-25

    Enhancing the optical absorption cross-section in topically important rare earth doped tellurite glasses is challenging for photonic devices. Controlled synthesis and detailed characterizations of the optical properties of these glasses are important for the optimization. The influence of varying concentration of Er{sup 3+} ions on the absorbance characteristics of lead tellurite glasses synthesized via melt-quenching technique are investigated. The UV-Vis absorption spectra exhibits six prominent peaks centered at 490, 526, 652, 800, 982 and 1520 nm ascribed to the transitions in erbium ion from the ground state to the excited states {sup 4}F{sub 7/2}, {sup 2}H{sub 11/2}, {sup 4}F{sub 9/2}, {sup 4}I{sub 9/2}, {sup 2}H{sub 11/2} and {sup 4}I{sub 13/2}, respectively. The results are analyzed by means of optical band gap E{sub g} and Urbach energy E{sub u}. The values of the energy band gap are found decreased from 2.82 to 2.51 eV and the Urbach energy increased from 0.15 to 0.24 eV with the increase of the Er{sub 2}O{sub 3} concentration from 0 to 1.5 mol%. The excellent absorbance of the prepared tellurite glasses makes them suitable for fabricating solid state lasers.

  6. Ejection Fraction Heart Failure Measurement

    MedlinePlus

    ... Thromboembolism Aortic Aneurysm More Ejection Fraction Heart Failure Measurement Updated:Feb 15,2017 The ejection fraction (EF) is an important measurement in determining how well your heart is pumping ...

  7. Determination of decay coefficients for combustors with acoustic absorbers

    NASA Technical Reports Server (NTRS)

    Mitchell, C. E.; Espander, W. R.; Baer, M. R.

    1972-01-01

    An analytical technique for the calculation of linear decay coefficients in combustors with acoustic absorbers is presented. Tuned circumferential slot acoustic absorbers were designed for the first three transverse modes of oscillation, and decay coefficients for these absorbers were found as a function of backing distance for seven different chamber configurations. The effectiveness of the absorbers for off-design values of the combustion response and acoustic mode is also investigated. Results indicate that for tuned absorbers the decay coefficient increases approximately as the cube of the backing distance. For most off-design situations the absorber still provides a damping effect. However, if an absorber designed for some higher mode of oscillation is used to damp lower mode oscillations, a driving effect is frequently found.

  8. Container and method for absorbing and reducing hydrogen concentration

    DOEpatents

    Wicks, George G.; Lee, Myung W.; Heung, Leung K.

    2001-01-01

    A method for absorbing hydrogen from an enclosed environment comprising providing a vessel; providing a hydrogen storage composition in communication with a vessel, the hydrogen storage composition further comprising a matrix defining a pore size which permits the passage of hydrogen gas while blocking the passage of gaseous poisons; placing a material within the vessel, the material evolving hydrogen gas; sealing the vessel; and absorbing the hydrogen gas released into the vessel by the hydrogen storage composition. A container for absorbing evolved hydrogen gas comprising: a vessel having an interior and adapted for receiving materials which release hydrogen gas; a hydrogen absorbing composition in communication with the interior, the composition defining a matrix surrounding a hydrogen absorber, the matrix permitting the passage of hydrogen gas while excluding gaseous poisons; wherein, when the vessel is sealed, hydrogen gas, which is released into the vessel interior, is absorbed by the hydrogen absorbing composition.

  9. Composite neutron absorbing coatings for nuclear criticality control

    DOEpatents

    Wright, Richard N.; Swank, W. David; Mizia, Ronald E.

    2005-07-19

    Thermal neutron absorbing composite coating materials and methods of applying such coating materials to spent nuclear fuel storage systems are provided. A composite neutron absorbing coating applied to a substrate surface includes a neutron absorbing layer overlying at least a portion of the substrate surface, and a corrosion resistant top coat layer overlying at least a portion of the neutron absorbing layer. An optional bond coat layer can be formed on the substrate surface prior to forming the neutron absorbing layer. The neutron absorbing layer can include a neutron absorbing material, such as gadolinium oxide or gadolinium phosphate, dispersed in a metal alloy matrix. The coating layers may be formed by a plasma spray process or a high velocity oxygen fuel process.

  10. A shock absorber model for structure-borne noise analyses

    NASA Astrophysics Data System (ADS)

    Benaziz, Marouane; Nacivet, Samuel; Thouverez, Fabrice

    2015-08-01

    Shock absorbers are often responsible for undesirable structure-borne noise in cars. The early numerical prediction of this noise in the automobile development process can save time and money and yet remains a challenge for industry. In this paper, a new approach to predicting shock absorber structure-borne noise is proposed; it consists in modelling the shock absorber and including the main nonlinear phenomena responsible for discontinuities in the response. The model set forth herein features: compressible fluid behaviour, nonlinear flow rate-pressure relations, valve mechanical equations and rubber mounts. The piston, base valve and complete shock absorber model are compared with experimental results. Sensitivity of the shock absorber response is evaluated and the most important parameters are classified. The response envelope is also computed. This shock absorber model is able to accurately reproduce local nonlinear phenomena and improves our state of knowledge on potential noise sources within the shock absorber.

  11. Absorber Alignment Measurement Tool for Solar Parabolic Trough Collectors: Preprint

    SciTech Connect

    Stynes, J. K.; Ihas, B.

    2012-04-01

    As we pursue efforts to lower the capital and installation costs of parabolic trough solar collectors, it is essential to maintain high optical performance. While there are many optical tools available to measure the reflector slope errors of parabolic trough solar collectors, there are few tools to measure the absorber alignment. A new method is presented here to measure the absorber alignment in two dimensions to within 0.5 cm. The absorber alignment is measured using a digital camera and four photogrammetric targets. Physical contact with the receiver absorber or glass is not necessary. The alignment of the absorber is measured along its full length so that sagging of the absorber can be quantified with this technique. The resulting absorber alignment measurement provides critical information required to accurately determine the intercept factor of a collector.

  12. Interpretation of FRESCO cloud retrievals in case of absorbing aerosol events

    NASA Astrophysics Data System (ADS)

    Wang, P.; Tuinder, O. N. E.; Tilstra, L. G.; Stammes, P.

    2011-12-01

    Cloud and aerosol information is needed in trace gas retrievals from satellite measurements. The Fast REtrieval Scheme for Clouds from the Oxygen A band (FRESCO) cloud algorithm employs reflectance spectra of the O2 A band around 760 nm to derive cloud pressure and effective cloud fraction. In general, clouds contribute more to the O2 A band reflectance than aerosols. Therefore, the FRESCO algorithm does not correct for aerosol effects in the retrievals and attributes the retrieved cloud information entirely to the presence of clouds, and not to aerosols. For events with high aerosol loading, aerosols may have a dominant effect, especially for almost cloud-free scenes. We have analysed FRESCO cloud data and Absorbing Aerosol Index (AAI) data from the Global Ozone Monitoring Experiment (GOME-2) instrument on the Metop-A satellite for events with typical absorbing aerosol types, such as volcanic ash, desert dust and smoke. We find that the FRESCO effective cloud fractions are correlated with the AAI data for these absorbing aerosol events and that the FRESCO cloud pressures contain information on aerosol layer pressure. For cloud-free scenes, the derived FRESCO cloud pressures are close to those of the aerosol layer for optically thick aerosols. For cloudy scenes, if the strongly absorbing aerosols are located above the clouds, then the retrieved FRESCO cloud pressures may represent the height of the aerosol layer rather than the height of the clouds. Combining FRESCO cloud data and AAI, an estimate for the aerosol layer pressure can be given, which can be beneficial for aviation safety and operations in case of e.g. volcanic ash plumes.

  13. Fractional Hopfield Neural Networks: Fractional Dynamic Associative Recurrent Neural Networks.

    PubMed

    Pu, Yi-Fei; Yi, Zhang; Zhou, Ji-Liu

    2016-07-14

    This paper mainly discusses a novel conceptual framework: fractional Hopfield neural networks (FHNN). As is commonly known, fractional calculus has been incorporated into artificial neural networks, mainly because of its long-term memory and nonlocality. Some researchers have made interesting attempts at fractional neural networks and gained competitive advantages over integer-order neural networks. Therefore, it is naturally makes one ponder how to generalize the first-order Hopfield neural networks to the fractional-order ones, and how to implement FHNN by means of fractional calculus. We propose to introduce a novel mathematical method: fractional calculus to implement FHNN. First, we implement fractor in the form of an analog circuit. Second, we implement FHNN by utilizing fractor and the fractional steepest descent approach, construct its Lyapunov function, and further analyze its attractors. Third, we perform experiments to analyze the stability and convergence of FHNN, and further discuss its applications to the defense against chip cloning attacks for anticounterfeiting. The main contribution of our work is to propose FHNN in the form of an analog circuit by utilizing a fractor and the fractional steepest descent approach, construct its Lyapunov function, prove its Lyapunov stability, analyze its attractors, and apply FHNN to the defense against chip cloning attacks for anticounterfeiting. A significant advantage of FHNN is that its attractors essentially relate to the neuron's fractional order. FHNN possesses the fractional-order-stability and fractional-order-sensitivity characteristics.

  14. Method of absorbing UF.sub.6 from gaseous mixtures in alkamine absorbents

    DOEpatents

    Lafferty, Robert H.; Smiley, Seymour H.; Radimer, Kenneth J.

    1976-04-06

    A method of recovering uranium hexafluoride from gaseous mixtures employing as an absorbent a liquid composition at least one of the components of which is chosen from the group consisting of ethanolamine, diethanolamine, and 3-methyl-3-amino-propane-diol-1,2.

  15. How Weird Are Weird Fractions?

    ERIC Educational Resources Information Center

    Stuffelbeam, Ryan

    2013-01-01

    A positive rational is a weird fraction if its value is unchanged by an illegitimate, digit-based reduction. In this article, we prove that each weird fraction is uniquely weird and initiate a discussion of the prevalence of weird fractions.

  16. The random continued fraction transformation

    NASA Astrophysics Data System (ADS)

    Kalle, Charlene; Kempton, Tom; Verbitskiy, Evgeny

    2017-03-01

    We introduce a random dynamical system related to continued fraction expansions. It uses random combinations of the Gauss map and the Rényi (or backwards) continued fraction map. We explore the continued fraction expansions that this system produces, as well as the dynamical properties of the system.

  17. Fractional diffusion on bounded domains

    DOE PAGES

    Defterli, Ozlem; D'Elia, Marta; Du, Qiang; ...

    2015-03-13

    We found that the mathematically correct specification of a fractional differential equation on a bounded domain requires specification of appropriate boundary conditions, or their fractional analogue. In this paper we discuss the application of nonlocal diffusion theory to specify well-posed fractional diffusion equations on bounded domains.

  18. Numerical approaches to fractional calculus and fractional ordinary differential equation

    NASA Astrophysics Data System (ADS)

    Li, Changpin; Chen, An; Ye, Junjie

    2011-05-01

    Nowadays, fractional calculus are used to model various different phenomena in nature, but due to the non-local property of the fractional derivative, it still remains a lot of improvements in the present numerical approaches. In this paper, some new numerical approaches based on piecewise interpolation for fractional calculus, and some new improved approaches based on the Simpson method for the fractional differential equations are proposed. We use higher order piecewise interpolation polynomial to approximate the fractional integral and fractional derivatives, and use the Simpson method to design a higher order algorithm for the fractional differential equations. Error analyses and stability analyses are also given, and the numerical results show that these constructed numerical approaches are efficient.

  19. Fractional chemotaxis diffusion equations.

    PubMed

    Langlands, T A M; Henry, B I

    2010-05-01

    We introduce mesoscopic and macroscopic model equations of chemotaxis with anomalous subdiffusion for modeling chemically directed transport of biological organisms in changing chemical environments with diffusion hindered by traps or macromolecular crowding. The mesoscopic models are formulated using continuous time random walk equations and the macroscopic models are formulated with fractional order differential equations. Different models are proposed depending on the timing of the chemotactic forcing. Generalizations of the models to include linear reaction dynamics are also derived. Finally a Monte Carlo method for simulating anomalous subdiffusion with chemotaxis is introduced and simulation results are compared with numerical solutions of the model equations. The model equations developed here could be used to replace Keller-Segel type equations in biological systems with transport hindered by traps, macromolecular crowding or other obstacles.

  20. Soot Volume Fraction Imaging

    NASA Technical Reports Server (NTRS)

    Greenberg, Paul S.; Ku, Jerry C.

    1994-01-01

    A new technique is described for the full-field determination of soot volume fractions via laser extinction measurements. This technique differs from previously reported point-wise methods in that a two-dimensional array (i.e., image) of data is acquired simultaneously. In this fashion, the net data rate is increased, allowing the study of time-dependent phenomena and the investigation of spatial and temporal correlations. A telecentric imaging configuration is employed to provide depth-invariant magnification and to permit the specification of the collection angle for scattered light. To improve the threshold measurement sensitivity, a method is employed to suppress undesirable coherent imaging effects. A discussion of the tomographic inversion process is provided, including the results obtained from numerical simulation. Results obtained with this method from an ethylene diffusion flame are shown to be in close agreement with those previously obtained by sequential point-wise interrogation.

  1. Thin absorber EUV photomask based on mixed Ni and TaN material

    NASA Astrophysics Data System (ADS)

    Hay, Derrick; Bagge, Patrick; Khaw, Ian; Sun, Lei; Wood, Obert; Chen, Yulu; Kim, Ryoung-han; Qi, Zhengqing John; Shi, Zhimin

    2016-05-01

    Lithographic patterning at the 7 and 5 nm nodes will likely require EUV (λ=13.5 nm) lithography for many of the critical levels. All optical elements in an EUV scanner are reflective which requires the EUV photomask to be illuminated at an angle to its normal. Current scanners have an incidence of 6 degree, but future designs will be <6 degrees for high-NA systems. Non-telecentricity has been shown to cause H-V bias due to shadowing, pattern shift through focus, and image contrast lost due to apodization by the reflective mask coating. A thinner EUV absorber can dramatically reduce these issues. Ni offers better EUV absorption than Ta-based materials, which hold promise as a thinner absorber candidate. Unfortunately, the challenge of etching Ni has prevented its adoption into manufacturing. We propose a new absorber material that infuses Ni nanoparticles into the TaN host medium, allowing for the use of established Ta etching chemistry. A thinner is absorber is created due to the enhanced absorption properties of the Ni-Ta nano-composite material. Finite integral method and effective medium theory-based transfer matrix method have been independently developed to analyze the performance of the nano-composite absorption layer. We show that inserting 15% volume fraction Ni nanoparticles into 40-nm of TaN absorber material can reduce the reflection below 2% over the EUV range. Numerical simulations confirm that the reduced reflectivity is due to the increased absorption of Ni, while scattering only contributes to approximately 0.2% of the reduction in reflectivity.

  2. Functional fractionation of platelets.

    PubMed

    Haver, V M; Gear, A R

    1981-02-01

    Studies of platelet populations suggest that they are heterogeneous in size, age, and metabolic parameters. In an attempt to correlate these parameters with efficiency of aggregation, a new technique, functional fractionation, was developed. Platelet populations are separated by their differential reactivity to aggregating agents. For example, low doses of ADP (0.1 to 0.7 microM) are added to stirred PRP, after which gentle centrifugation is used to remove aggregates from single unreacted platelets. The loose aggregates can be readily dispersed for comparison of the physical or biochemical properties of the reacted versus unreacted platelets. It was found that reactive platelets were larger (6.5 micrometer3) than unreacted platelets (5.51 micrometer3). No significant difference in density existed between the two populations, and no release of [14C]serotonin from prelabeled platelets occurred during functional fractionation. Scanning and transmission electron microscopy confirmed the size difference and revealed that in both populations platelets were structurally intact with a normal discoid shape and no significant difference in organelle content. Human platelets most reactive to ADP were also enriched in glycogen (3.6-fold), ATP (1.6-fold), and ADP (twofold), compared with less reactive cells. These "reactive" cells took up more 51[Cr] and contained 1.9 times more surface sialic acid. In an in vivo aging experiment, rats were injected with 75[Se]methionine. Shortly after labeling (1 day), the most reactive platelets possessed the highest amount of 75[Se]. These results reveal that functionally active platelets, which are also larger, are more active metabolically than less reactive platelets, possess a higher negative surface charge, and may be a younger population.

  3. Antioxidant activity and phenolic compositions of lentil (Lens culinaris var. Morton) extract and its fractions.

    PubMed

    Zou, Yanping; Chang, Sam K C; Gu, Yan; Qian, Steven Y

    2011-03-23

    Phenolic compounds were extracted from Morton lentils using acidified aqueous acetone. The crude Morton extract (CME) was applied onto a macroresin column and desorbed by aqueous methanol to obtain a semipurified Morton extract (SPME). The SPME was further fractionated over a Sephadex LH-20 column into five main fractions (I-V). The phytochemical contents such as total phenolic content (TPC), total flavonoid content (TFC), and condensed tannin content (CTC) of the CME, SPME, and its fractions were examined by colorimetric methods. Antioxidant activity of extracts and fractions were screened by DPPH scavenging activity, Trolox equivalent antioxidant capacity (TEAC), ferric reduced antioxidant power (FRAP), and oxygen radical absorbing capacity (ORAC) methods. In addition, the compositions of active fractions were determined by HPLC-DAD and HPLC-MS methods. Results showed that the fraction enriched in condensed tannins (fraction V) exhibited significantly higher values of TPC, CTC, and antioxidant activity as compared to the crude extract, SPME, and low molecular weight fractions (I-IV). Eighteen compounds existed in those fractions, and 17 were tentatively identified by UV and MS spectra. HPLC-MS analysis revealed fraction II contained mainly kaempferol glycoside, fractions III and IV mainly contained flavonoid glycosides, and fraction V was composed of condensed tannins. The results suggested that the extract of Morton lentils is a promising source of antioxidant phenolics and may be used as a dietary supplement for health promotion.

  4. Fraction Reduction in Membrane Systems

    PubMed Central

    Zhang, Hong

    2014-01-01

    Fraction reduction is a basic computation for rational numbers. P system is a new computing model, while the current methods for fraction reductions are not available in these systems. In this paper, we propose a method of fraction reduction and discuss how to carry it out in cell-like P systems with the membrane structure and the rules with priority designed. During the application of fraction reduction rules, synchronization is guaranteed by arranging some special objects in these rules. Our work contributes to performing the rational computation in P systems since the rational operands can be given in the form of fraction. PMID:24772037

  5. Ultrathin microwave absorber based on metamaterial

    NASA Astrophysics Data System (ADS)

    Kim, Y. J.; Yoo, Y. J.; Hwang, J. S.; Lee, Y. P.

    2016-11-01

    We suggest that ultrathin broadband metamaterial is a perfect absorber in the microwave regime by utilizing the properties of a resistive sheet and metamaterial. Meta-atoms are composed of four-leaf clover-shape metallic patterns and a metal plane separated by three intermediate resistive sheet layers between four dielectric layers. We interpret the absorption mechanism of the broadband by using the distribution of surface currents at specific frequencies. The simulated absorption was over 99% in 1.8-4.2 GHz. The corresponding experimental absorption was also over 99% in 2.62-4.2 GHz; however, the absorption was slightly lower than 99% in 1.8-2.62 GHz because of the sheet resistance and the changed values for the dielectric constant. Furthermore, it is independent of incident angle. The results of this research indicate the possibility of applications, due to the suppression of noxious exposure, in cell phones, computers and microwave equipments.

  6. Electromagnetic radiation absorbers and modulators comprising polyaniline

    DOEpatents

    Epstein, Arthur J.; Ginder, John M.; Roe, Mitchell G.; Hajiseyedjavadi, Hamid

    1992-01-01

    A composition for absorbing electromagnetic radiation, wherein said electromagnetic radiation possesses a wavelength generally in the range of from about 1000 Angstroms to about 50 meters, wherein said composition comprises a polyaniline composition of the formula ##STR1## where y can be equal to or greater than zero, and R.sup.1 and R.sup.2 are independently selected from the group containing of H, --OCH.sub.3, --CH.sub.3, --F, --Cl, --Br, --I, NR.sup.3 .sub.2, --NHCOR.sup.3, --OH, --O.sup.-, SR.sup.3, --OCOR.sup.3, --NO.sub.2, --COOH, --COOR.sup.3, --COR.sup.3, --CHO, and --CN, where R.sup.3 is a C.sub.1 to C.sub.8 alkyl, aryl or aralkyl group.

  7. Cusps, self-organization, and absorbing states.

    PubMed

    Bonachela, Juan A; Alava, Mikko; Muñoz, Miguel A

    2009-05-01

    Elastic interfaces embedded in (quenched) random media exhibit metastability and stick-slip dynamics. These nontrivial dynamical features have been shown to be associated with cusp singularities of the coarse-grained disorder correlator. Here we show that annealed systems with many absorbing states and a conservation law but no quenched disorder exhibit identical cusps. On the other hand, similar nonconserved systems in the directed percolation class are also shown to exhibit cusps but of a different type. These results are obtained both by a recent method to explicitly measure disorder correlators and by defining an alternative new protocol inspired by self-organized criticality, which opens the door to easily accessible experimental realizations.

  8. Electronic and thermally tunable infrared metamaterial absorbers

    NASA Astrophysics Data System (ADS)

    Shrekenhamer, David; Miragliotta, Joseph A.; Brinkley, Matthew; Fan, Kebin; Peng, Fenglin; Montoya, John A.; Gauza, Sebastian; Wu, Shin-Tson; Padilla, Willie J.

    2016-09-01

    In this paper, we report a computational and experimental study using tunable infrared (IR) metamaterial absorbers (MMAs) to demonstrate frequency tunable (7%) and amplitude modulation (61%) designs. The dynamic tuning of each structure was achieved through the addition of an active material—liquid crystals (LC) or vanadium dioxide (VO2)-within the unit cell of the MMA architecture. In both systems, an applied stimulus (electric field or temperature) induced a dielectric change in the active material and subsequent variation in the absorption and reflection properties of the MMA in the mid- to long-wavelength region of the IR (MWIR and LWIR, respectively). These changes were observed to be reversible for both systems and dynamic in the LC-based structure.

  9. Porous Carbon Nanoparticle Networks with Tunable Absorbability

    PubMed Central

    Dai, Wei; Kim, Seong Jin; Seong, Won-Kyeong; Kim, Sang Hoon; Lee, Kwang-Ryeol; Kim, Ho-Young; Moon, Myoung-Woon

    2013-01-01

    Porous carbon materials with high specific surface areas and superhydrophobicity have attracted much research interest due to their potential application in the areas of water filtration, water/oil separation, and oil-spill cleanup. Most reported superhydrophobic porous carbon materials are fabricated by complex processes involving the use of catalysts and high temperatures but with low throughput. Here, we present a facile single-step method for fabricating porous carbon nanoparticle (CNP) networks with selective absorbability for water and oils via the glow discharge of hydrocarbon plasma without a catalyst at room temperature. Porous CNP networks were grown by the continuous deposition of CNPs at a relatively high deposition pressure. By varying the fluorine content, the porous CNP networks exhibited tunable repellence against liquids with various degrees of surface tension. These porous CNP networks could be applied for the separation of not only water/oil mixtures but also mixtures of liquids with different surface tension levels. PMID:23982181

  10. Absorbing layers for the Dirac equation

    SciTech Connect

    Pinaud, Olivier

    2015-05-15

    This work is devoted to the construction of perfectly matched layers (PML) for the Dirac equation, that not only arises in relativistic quantum mechanics but also in the dynamics of electrons in graphene or in topological insulators. While the resulting equations are stable at the continuous level, some care is necessary in order to obtain a stable scheme at the discrete level. This is related to the so-called fermion doubling problem. For this matter, we consider the numerical scheme introduced by Hammer et al. [19], and combine it with the discretized PML equations. We state some arguments for the stability of the resulting scheme, and perform simulations in two dimensions. The perfectly matched layers are shown to exhibit, in various configurations, superior absorption than the absorbing potential method and the so-called transport-like boundary conditions.

  11. Absorbed doses from temporomandibular joint radiography

    SciTech Connect

    Brooks, S.L.; Lanzetta, M.L.

    1985-06-01

    Thermoluminescent dosimeters were used in a tissue-equivalent phantom to measure doses of radiation absorbed by various structures in the head when the temporomandibular joint was examined by four different radiographic techniques--the transcranial, transorbital, and sigmoid notch (Parma) projections and the lateral tomograph. The highest doses of radiation occurred at the point of entry for the x-ray beam, ranging from 112 mrad for the transorbital view to 990 mrad for the sigmoid notch view. Only the transorbital projection a radiation dose to the lens of the eye. Of the four techniques evaluated, the lateral tomograph produced the highest doses to the pituitary gland and the bone marrow, while the sigmoid notch radiograph produced the highest doses to the parotid gland.

  12. Microcellular ceramic foams for radar absorbing structures

    SciTech Connect

    Huling, J.; Phillips, D.

    1996-09-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project is to develop a lightweight, semi-structural, radar-absorbing ceramic foam that can be incorporated into aircraft exhaust systems to replace many of the currently used dense ceramic parts and thereby improve the radar cross section. Although the conventional processes for producing ceramic foams have not been able to provide materials that meet the design specifications for high strength at low density, we have developed and demonstrated a novel sol-gel emulsion process for preparing microcellular ceramic foams in which compositional and microstructural control is expected to provide the requisite high-temperature radar-absorption, strength-to-weight ratio, and thermal insulative properties.

  13. The foot as a shock absorber.

    PubMed

    Salathé, E P; Arangio, G A; Salathé, E P

    1990-01-01

    A mathematical analysis of the deformation of the foot is developed to determine the role that stretch of ligaments and tendons plays in absorbing shock following impact. Our analysis is based on an anatomical biomechanical model that includes each of the bones of the foot. We calculate the time course of the deflection of the joints and the elongation of the ligaments and tendons and determine the ground reaction force acting on the heel. Quasi-linear viscoelastic theory is used for soft tissue constitutive relationships. With biomechanical data selected from the literature, we obtain a vertical force impact peak of 8000 N, occurring at 16 ms following heel strike. This is of higher magnitude and shorter duration than is found experimentally, as is to be expected, since we did not include the heel pad in our model and we assumed that the impact surface was ideally rigid.

  14. Modelling and validation of electromechanical shock absorbers

    NASA Astrophysics Data System (ADS)

    Tonoli, Andrea; Amati, Nicola; Girardello Detoni, Joaquim; Galluzzi, Renato; Gasparin, Enrico

    2013-08-01

    Electromechanical vehicle suspension systems represent a promising substitute to conventional hydraulic solutions. However, the design of electromechanical devices that are able to supply high damping forces without exceeding geometric dimension and mass constraints is a difficult task. All these challenges meet in off-road vehicle suspension systems, where the power density of the dampers is a crucial parameter. In this context, the present paper outlines a particular shock absorber configuration where a suitable electric machine and a transmission mechanism are utilised to meet off-road vehicle requirements. A dynamic model is used to represent the device. Subsequently, experimental tests are performed on an actual prototype to verify the functionality of the damper and validate the proposed model.

  15. Energy harvesting from an autoparametric vibration absorber

    NASA Astrophysics Data System (ADS)

    Yan, Zhimiao; Hajj, Muhammad R.

    2015-11-01

    The combined control and energy harvesting characteristics of an autoparametric vibration absorber consisting of a base structure subjected to the external force and a cantilever beam with a tip mass are investigated. The piezoelectric sheets are attached to the cantilever beam to convert the vibrations of the base structure into electrical energy. The coupled nonlinear representative model is developed by using the extended Hamiton’s principle. The effects of the electrical load resistance on the frequency and damping ratio of the cantilever beam are analyzed. The impacts of the external force and load resistance on the structural displacements of the base structure and the beam and on the level of harvested energy are determined. The results show that the initial conditions have a significant impact on the system’s response. The relatively high level of energy harvesting is not necessarily accompanied with the minimum displacements of the base structure.

  16. Skin interaction with absorbent hygiene products.

    PubMed

    Runeman, Bo

    2008-01-01

    Skin problems due to the use of absorbent hygiene products, such as diapers, incontinence pads, and feminine sanitary articles, are mostly due to climate or chafing discomfort. If these conditions are allowed to prevail, these may develop into an irritant contact dermatitis and eventually superficial skin infections. Skin humidity and aging skin are among the most significant predisposing and aggravating factors for dermatitis development. Improved product design features are believed to explain the decline in observed diaper dermatitis among infants. Where adult incontinence-related skin problems are concerned, it is very important to apply a holistic perspective to understand the influences due to the individual's incontinence level and skin condition, as well as the hygiene and skin care measures provided. Individuals with frail, sensitive skin or with skin diseases may preferably have to use high-quality products, equipped with superabsorbent polymers and water vapor-permeable back sheets, to minimize the risk of skin complications.

  17. Metallic rugate structures for near-perfect absorbers in visible and near-infrared regions.

    PubMed

    Shu, Shiwei; Li, Yang Yang

    2012-09-01

    Metallic rugate structures are theoretically investigated for achieving near-perfect absorption in the visible and near-infrared regions. Our model builds on nanoporous metal films whose porosity (volume fraction of voids) follows a sinewave along the film thickness. By setting the initial phase of porosity at the top surface as 0, near-perfect absorption is obtained. The impacts of various structural parameters on the characteristic absorption behaviors are studied. Furthermore, multiple peaks or bands with high absorption can be achieved by integrating several periodicities in one structure. The rugate absorbers show near-perfect absorption for TE and TM polarizations and large incident angles.

  18. Absorbable plate strength loss during molding.

    PubMed

    Ballard, Tiffany N S; Kelly, Kevin J; Zaydfudim, Victor; Walcutt, Noah L; Lahijani, Soheil S; Shack, R Bruce; Thayer, Wesley P

    2010-05-01

    Bioabsorbable plating systems play an integral role in cranial vault remodeling. After experiencing a case of plate failure requiring emergent reexploration, we investigated the potential causes. We hypothesize that extended submersion in the molding bath during plate preparation might advance the rate of hydrolysis and compromise plate structural integrity. Using an absorbable poly-D/L-lactic acid plating system, we assessed the effect of extended submersion on plate strength and stiffness when loaded in a cantilever fashion and with pure tension. We assessed these differences with the Student t test and linear regression modeling. We also generated a computer model of the plates for finite element analysis. When left in the molding bath for extended periods, the plates changed color and lost strength. After 5 minutes, 30% of maximum plate load capacity was lost in a cantilever beam test (P < 0.001) consistent with use of a 15% thinner plate. Tensile testing revealed the initial elastic modulus of 6.42 +/- 0.13 GPa decreased 16% to 5.41 +/- 0.50 GPa after 5 minutes of submersion (P = 0.027). The changes in plate strength and elastic modulus both worsened with increased submersion times. Finite element analysis of the plates also predicted clinically significant increases in plate deviation under normal loading conditions. Our study demonstrates that extended submersion of absorbable plates during molding results in a significant loss of plate strength and stiffness. Further, our computer model predicts that these changes could result in an unacceptable plate deviation under normal loading conditions. Together, these data caution against overmolding of plates to avoid compromising their structural integrity.

  19. Light Absorbing Aerosols in Mexico City

    NASA Astrophysics Data System (ADS)

    Marley, N. A.; Kelley, K. L.; Kilaparty, P. S.; Gaffney, J. S.

    2008-12-01

    The direct effects of aerosol radiative forcing has been identified by the IPCC as a major uncertainty in climate modeling. The DOE Megacity Aerosol Experiment-Mexico City (MAX-Mex), as part of the MILAGRO study in March of 2006, was undertaken to reduce these uncertainties by characterization of the optical, chemical, and physical properties of atmospheric aerosols emitted from this megacity environment. Aerosol samples collected during this study using quartz filters were characterized in the uv-visible-infrared by using surface spectroscopic techniques. These included the use of an integrating sphere approach combined with the use of Kubelka-Munk theory to obtain aerosol absorption spectra. In past work black carbon has been assumed to be the only major absorbing species in atmospheric aerosols with an broad band spectral profile that follows a simple inverse wavelength dependence. Recent work has also identified a number of other absorbing species that can also add to the overall aerosol absorption. These include primary organics from biomass and trash burning and secondary organic aerosols including nitrated PAHs and humic-like substances, or HULIS. By using surface diffuse reflection spectroscopy we have also obtained spectra in the infrared that indicate significant IR absorption in the atmospheric window-region. These data will be presented and compared to spectra of model compounds that allow for evaluation of the potential importance of these species in adding strength to the direct radiative forcing of atmospheric aerosols. This work was supported by the Office of Science (BER), U.S. Department of Energy, Grant No. DE-FG02-07ER64327 as part of the Atmospheric Science Program.

  20. HPLC method to characterize cyanogen bromide collagen fractions containing pyridinoline groups.

    PubMed

    Bruno, R; Mazza, R; Calafiori, A R; Covello, C; Falbo, L; Martino, G; Marotta, M

    1997-01-01

    The HPLC method here described allows to separate CNBr collagen peptides within 2.5 h by reversed phase and gradient elution. The method is useful to determine both peptide bond and pyridinoline groups by absorbance spectophotometry. The fractions can be recovered and then submitted to other characterization techniques.

  1. Effects of dissolved organic matter size fractions on trihalomethanes formation in MBR effluents during chlorine disinfection.

    PubMed

    Ma, Defang; Gao, Baoyu; Sun, Shenglei; Wang, Yan; Yue, Qinyan; Li, Qian

    2013-05-01

    In this study, effects of dissolved organic matter (DOM) size fractions on trihalomethanes (THMs) formation in MBR effluents during chlorination were investigated by fractionating DOM into >100, 30-100, 10-30, 5-10 and <5 kDa fractions using ultrafiltration (UF) membranes based on molecular weight (MW). Fractions of MW>30 kDa constituted 87% of DOM and were the main THMs precursors, which exhibited higher specific ultraviolet absorbance (SUVA) and THMs formation potential (THMFP) and should be reduced to control THMs formation. For these fractions, THMs formation was mostly attributed to slow chlorine decay, and THMs yield coefficients were low because halogenated intermediates derived from the macromolecular DOM were difficult to decompose to produce THMs. Moreover, there was a strong linear correlation between dissolved organic carbon (DOC) concentration and THMFP (R(2)=0.981), as well as between the SUVA and specific THMFP (R(2)=0.993) in all fractions.

  2. The Synergism Between Heat and Mass Transfer Additive and Advanced Surfaces in Aqueous LiBr Horizontal Tube Absorbers

    SciTech Connect

    Miller, W.A.

    1999-03-24

    Experiments were conducted in a laboratory to investigate the absorption of water vapor into a falling-film of aqueous lithium bromide (LiBr). A mini-absorber test stand was used to test smooth tubes and a variety of advanced tube surfaces placed horizontally in a single-row bundle. The bundle had six copper tubes; each tube had an outside diameter of 15.9-mm and a length of 0.32-m. A unique feature of the stand is its ability to operate continuously and support testing of LiBr brine at mass fractions {ge} 0.62. The test stand can also support testing to study the effect of the failing film mass flow rate, the coolant mass flow rate, the coolant temperature, the absorber pressure and the tube spacing. Manufacturers of absorption chillers add small quantities of a heat and mass transfer additive to improve the performance of the absorbers. The additive causes surface stirring which enhances the transport of absorbate into the bulk of the film. Absorption may also be enhanced with advanced tube surfaces that mechanically induce secondary flows in the falling film without increasing the thickness of the film. Several tube geometry's were identified and tested with the intent of mixing the film and renewing the interface with fresh solution from the tube wall. Testing was completed on a smooth tube and several different externally enhanced tube surfaces. Experiments were conducted over the operating conditions of 6.5 mm Hg absorber pressure, coolant temperatures ranging from 20 to 35 C and LiBr mass fractions ranging from 0.60 through 0.62. Initially the effect of tube spacing was investigated for the smooth tube surface, tested with no heat and mass transfer additive. Test results showed the absorber load and the mass absorbed increased as the tube spacing increased because of the improved wetting of the tube bundle. However, tube spacing was not a critical factor if heat and mass transfer additive was active in the mini-absorber. The additive dramatically affected

  3. Structure, optical properties and thermal stability of Al2O3-WC nanocomposite ceramic spectrally selective solar absorbers

    NASA Astrophysics Data System (ADS)

    Gao, Xiang-Hu; Wang, Cheng-Bing; Guo, Zhi-Ming; Geng, Qing-Fen; Theiss, Wolfgang; Liu, Gang

    2016-08-01

    Traditional metal-dielectric composite coating has found important application in spectrally selective solar absorbers. However, fine metal particles can easily diffuse, congregate, or be oxidized at high temperature, which causes deterioration in the optical properties. In this work, we report a new spectrally selective solar absorber coating, composed of low Al2O3 ceramic volume fraction (Al2O3(L)-WC) layer, high Al2O3 ceramic volume fraction (Al2O3(H)-WC layer) and Al2O3 antireflection layer. The features of our work are: 1) compared with the metal-dielectric composites concept, Al2O3-WC nanocomposite ceramic successfully achieves the all-ceramic concept, which exhibits a high solar absorptance of 0.94 and a low thermal emittance of 0.08, 2) Al2O3 and WC act as filler material and host material, respectively, which are different from traditional concept, 3) Al2O3-WC nanocomposite ceramic solar absorber coating exhibits good thermal stability at 600 °C. In addition, the solar absorber coating is successfully modelled by a commercial optical simulation programme, the result of which agrees with the experimental results.

  4. Fractionally charged skyrmions in fractional quantum Hall effect.

    PubMed

    Balram, Ajit C; Wurstbauer, U; Wójs, A; Pinczuk, A; Jain, J K

    2015-11-26

    The fractional quantum Hall effect has inspired searches for exotic emergent topological particles, such as fractionally charged excitations, composite fermions, abelian and nonabelian anyons and Majorana fermions. Fractionally charged skyrmions, which support both topological charge and topological vortex-like spin structure, have also been predicted to occur in the vicinity of 1/3 filling of the lowest Landau level. The fractional skyrmions, however, are anticipated to be exceedingly fragile, suppressed by very small Zeeman energies. Here we show that, slightly away from 1/3 filling, the smallest manifestations of the fractional skyrmion exist in the excitation spectrum for a broad range of Zeeman energies, and appear in resonant inelastic light scattering experiments as well-defined resonances slightly below the long wavelength spin wave mode. The spectroscopy of these exotic bound states serves as a sensitive tool for investigating the residual interaction between composite fermions, responsible for delicate new fractional quantum Hall states in this filling factor region.

  5. Fractionally charged skyrmions in fractional quantum Hall effect

    SciTech Connect

    Balram, Ajit C.; Wurstbauer, U.; Wójs, A.; Pinczuk, A.; Jain, J. K.

    2015-11-26

    The fractional quantum Hall effect has inspired searches for exotic emergent topological particles, such as fractionally charged excitations, composite fermions, abelian and nonabelian anyons and Majorana fermions. Fractionally charged skyrmions, which support both topological charge and topological vortex-like spin structure, have also been predicted to occur in the vicinity of 1/3 filling of the lowest Landau level. The fractional skyrmions, however, are anticipated to be exceedingly fragile, suppressed by very small Zeeman energies. Here we show that, slightly away from 1/3 filling, the smallest manifestations of the fractional skyrmion exist in the excitation spectrum for a broad range of Zeeman energies, and appear in resonant inelastic light scattering experiments as well-defined resonances slightly below the long wavelength spin wave mode. The spectroscopy of these exotic bound states serves as a sensitive tool for investigating the residual interaction between composite fermions, responsible for delicate new fractional quantum Hall states in this filling factor region.

  6. A control strategy for adaptive absorber based on variable mass

    NASA Astrophysics Data System (ADS)

    Gao, Qiang; Han, Ning; Zhao, Yanqing; Duan, Chendong; Wang, Wanqin

    2015-07-01

    The tuned vibration absorber (TVA) has been an effective tool for vibration control. However, the application of TVA can cause resonance of the primary system and increase its vibration when the absorber is mistuned. In this paper, a novel control strategy based on adaptive tuned vibration absorber (ATVA) of variable mass is proposed to reduce the resonance of the primary system. Unlike most ATVAs suggested by other researchers which adjust the absorber natural frequency by changing the stiffness, the variable mass ATVA varies its natural frequency by changing absorber mass to match the excitation frequency. Some simulations and experiments were conducted to test the performance of the control strategy. The results show that the proposed control plan can widen the frequency bandwidth of the absorber, as well as suppress the resonance of the primary system significantly. This implies that the work is useful for practical applications of ATVA.

  7. Polarization independent broadband metamaterial absorber based on tapered helical structure

    NASA Astrophysics Data System (ADS)

    Agarwal, Sajal; Prajapati, Y. K.; Singh, V.; Saini, J. P.

    2015-12-01

    This communication presents a tapered helical structure as absorber, made of unconventional material i.e. metamaterial. Modeling, analytical study and the optimization of the absorber have been done. Quad helical optimized structure gives almost unity absorption at 499 nm wavelength and gives the absorption more than 75% from 300 nm to 1650 nm which is a very wide operating region with, average absorbance of 91.32%. Whereas, triple helical structure gives 85% average absorbance with the operating range from 300 nm to 1350 nm. Also, it is analyzed that the presented structures are polarization independent and broadband. Comparison of the proposed quad helical absorber with the existing metamaterial absorbers is done and found it is most eligible.

  8. Fractional variational calculus in terms of Riesz fractional derivatives

    NASA Astrophysics Data System (ADS)

    Agrawal, O. P.

    2007-06-01

    This paper presents extensions of traditional calculus of variations for systems containing Riesz fractional derivatives (RFDs). Specifically, we present generalized Euler-Lagrange equations and the transversality conditions for fractional variational problems (FVPs) defined in terms of RFDs. We consider two problems, a simple FVP and an FVP of Lagrange. Results of the first problem are extended to problems containing multiple fractional derivatives, functions and parameters, and to unspecified boundary conditions. For the second problem, we present Lagrange-type multiplier rules. For both problems, we develop the Euler-Lagrange-type necessary conditions which must be satisfied for the given functional to be extremum. Problems are considered to demonstrate applications of the formulations. Explicitly, we introduce fractional momenta, fractional Hamiltonian, fractional Hamilton equations of motion, fractional field theory and fractional optimal control. The formulations presented and the resulting equations are similar to the formulations for FVPs given in Agrawal (2002 J. Math. Anal. Appl. 272 368, 2006 J. Phys. A: Math. Gen. 39 10375) and to those that appear in the field of classical calculus of variations. These formulations are simple and can be extended to other problems in the field of fractional calculus of variations.

  9. Measurement and Simulation Results of Ti Coated Microwave Absorber

    SciTech Connect

    Sun, Ding; McGinnis, Dave; /Fermilab

    1998-11-01

    When microwave absorbers are put in a waveguide, a layer of resistive coating can change the distribution of the E-M fields and affect the attenuation of the signal within the microwave absorbers. In order to study such effect, microwave absorbers (TT2-111) were coated with titanium thin film. This report is a document on the coating process and measurement results. The measurement results have been used to check the simulation results from commercial software HFSS (High Frequency Structure Simulator.)

  10. Design of Tunable, Thin, and Wide-band Microwave Absorbers

    DTIC Science & Technology

    2012-04-05

    switchable or tunable radar absorbers, which are very useful in electromagnetic compatibility test facilities, radar camouflage and deception roles, and...applications requires switchable or tunable radar absorbers, which are very useful in electromagnetic compatibility test facilities, radar camouflage ...2012. [2] Q. Zhang and Z. Shen, “A dual-polarized switchable microwave absorber,” IEEE AP- S International Symposium , Chicago, July 2012.

  11. Vertical-plane pendulum absorbers for minimizing helicopter vibratory loads

    NASA Technical Reports Server (NTRS)

    Amer, K. B.; Neff, J. R.

    1974-01-01

    The use of pendulum dynamic absorbers mounted on the blade root and operating in the vertical plane to minimize helicopter vibratory loads was discussed. A qualitative description was given of the concept of the dynamic absorbers and some results of analytical studies showing the degree of reduction in vibratory loads attainable are presented. Operational experience of vertical plane dynamic absorbers on the OH-6A helicopter is also discussed.

  12. Dual band metamaterial perfect absorber based on artificial dielectric "molecules".

    PubMed

    Liu, Xiaoming; Lan, Chuwen; Li, Bo; Zhao, Qian; Zhou, Ji

    2016-07-13

    Dual band metamaterial perfect absorbers with two absorption bands are highly desirable because of their potential application areas such as detectors, transceiver system, and spectroscopic imagers. However, most of these dual band metamaterial absorbers proposed were based on resonances of metal patterns. Here, we numerically and experimentally demonstrate a dual band metamaterial perfect absorber composed of artificial dielectric "molecules" with high symmetry. The artificial dielectric "molecule" consists of four "atoms" of two different sizes corresponding to two absorption bands with near unity absorptivity. Numerical and experimental absorptivity verify that the dual-band metamaterial absorber is polarization insensitive and can operate in wide-angle incidence.

  13. Optimal active vibration absorber: Design and experimental results

    NASA Technical Reports Server (NTRS)

    Lee-Glauser, Gina; Juang, Jer-Nan; Sulla, Jeffrey L.

    1992-01-01

    An optimal active vibration absorber can provide guaranteed closed-loop stability and control for large flexible space structures with collocated sensors/actuators. The active vibration absorber is a second-order dynamic system which is designed to suppress any unwanted structural vibration. This can be designed with minimum knowledge of the controlled system. Two methods for optimizing the active vibration absorber parameters are illustrated: minimum resonant amplitude and frequency matched active controllers. The Controls-Structures Interaction Phase-1 Evolutionary Model at NASA LaRC is used to demonstrate the effectiveness of the active vibration absorber for vibration suppression. Performance is compared numerically and experimentally using acceleration feedback.

  14. Anomalous Moessbauer Fraction in Superparamagnetic Systems.

    NASA Astrophysics Data System (ADS)

    Mohie-Eldin, Mohie-Eldin Yehia

    The biological molecule ferritin and its proven synthetic counterpart polysaccharide iron complex (P.I.C.) have been shown to contain small (<100 ^circ in diameter) antiferromagnetic cores at their centers. Mossbauer studies of these molecules have revealed an anomalous drop in the Mossbauer fraction (f-factor) as the temperature rises above 30^ circK for mammalian ferritin and 60 ^circK for P.I.C. Above the blocking temperature, superparamagnetic relaxation results in the disappearance of hyperfine splitting. This thesis investigates and attempts to resolve this Lamb-Mossbauer f-Factor anomaly in these superparamagnetically relaxing systems. Chapter I deals with a basic review of theories of Mossbauer spectroscopy and superparamagnetism. The analogies in the composition of the two molecules is examined in Chapter II. The long range order technique of magnetization measurements is used in Chapter III to compare magnetic properties of both molecules and to verify the suggestion that the P.I.C. molecule is a good "biomimic" to ferritin based on the identification of ferrihydrite as the major mineral in both, by short range probing techniques such as X-ray diffraction. The anomaly is confirmed in P.I.C.'s Mossbauer spectra in Chapter IV. Different absorbers are used to experimentally investigate the absorber thickness effect on the Mossbauer spectra. The anomaly persists for thin absorbers. Also in Chapter V, data that is treated with FFT procedures to eliminate the thickness effect still exhibit this anomaly. We then investigated the effect of superparamagnetic relaxation on the f-factor. In Chapter VI, spin-lattice relaxation was excluded based upon a calculation of the rate of energy transfer from the spin system to the lattice. We introduce a theory in Chapter VII based on the following process as a plausible explanation of the anomaly: Superparamagnetic relaxation brings about a dynamical displacement of the Mossbauer nucleus through magnetostriction. These

  15. Microscopic analysis of saturable absorbers: Semiconductor saturable absorber mirrors versus graphene

    SciTech Connect

    Hader, J.; Moloney, J. V.; Yang, H.-J.; Scheller, M.; Koch, S. W.

    2016-02-07

    Fully microscopic many-body calculations are used to study the influence of strong sub-picosecond pulses on the carrier distributions and corresponding optical response in saturable absorbers used for mode-locking—semiconductor (quantum well) saturable absorber mirrors (SESAMs) and single layer graphene based saturable absorber mirrors (GSAMs). Unlike in GSAMs, the saturation fluence and recovery time in SESAMs show a strong spectral dependence. While the saturation fluence in the SESAM is minimal at the excitonic bandgap, the optimal recovery time and least pulse distortion due to group delay dispersion are found for excitation higher in the first subband. For excitation near the SESAM bandgap, the saturation fluence is about one tenth of that in the GSAM. At energies above the bandgap, the fluences in both systems become similar. A strong dependence of the saturation fluence on the pulse width in both systems is caused by carrier relaxation during the pulse. The recovery time in graphene is found to be about two to four times faster than that in the SESAMs. The occurrence of negative differential transmission in graphene is shown to be caused by dopant related carriers. In SESAMs, a negative differential transmission is found when exciting below the excitonic resonance where excitation induced dephasing leads to an enhancement of the absorption. Comparisons of the simulation data to the experiment show a very good quantitative agreement.

  16. Inevitable iron loss by human adolescents, with calculations of the requirement for absorbed iron.

    PubMed

    Fomon, Samuel J; Drulis, Jean M; Nelson, Steven E; Serfass, Robert E; Woodhead, Jerold C; Ziegler, Ekhard E

    2003-01-01

    In growing individuals, the requirement for absorbed iron consists of iron needed for growth and iron needed to replace inevitable iron loss. We were able to estimate inevitable iron loss by adolescents because total body iron of the adolescents had been enriched with the stable isotope, (58)Fe, as the result of earlier studies of iron absorption. During an interval beginning at least 1.56 y after isotope administration (a time sufficient for complete mixing of the isotope with total body iron) and extending for no less than 3.29 y, we determined the isotopic enrichment of circulating iron. On the basis of several assumptions, we calculated total body (58)Fe and total body iron at the beginning and end of the interval. Because of complete mixing of the isotope with total body iron, fractional total (58)Fe loss was the same as fractional loss of total iron. In males, the fractional loss of iron was 9.70%/y and the quantitative loss was 256 mg/y or 0.70 mg/d. In females, the fractional loss of iron was 14.60%/y and the quantitative loss was 306 mg/y or 0.84 mg/d. Using several assumptions, we then calculated that the iron requirement for growth during this interval was 0.76 mg/d for males and 0.31 mg/d for females. Adding the iron loss to the iron requirement for growth, the requirement for absorbed iron was estimated to be 1.46 mg/d for males and 1.15 mg/d for females.

  17. The Multi-Layer Variable Absorbers in NGC 1365 Revealed by XMM-Newton and NuSTAR

    NASA Technical Reports Server (NTRS)

    Rivers, E.; Risaliti, G.; Walton, D. J.; Harrison, F.; Arevalo, P.; Baur, F. E.; Boggs, S. E.; Brenneman, L. W.; Brightman, M.; Zhang, W. W.

    2015-01-01

    Between 2012 July and 2013 February, NuSTAR and XMM-Newton performed four long-look joint observations of the type 1.8 Seyfert, NGC 1365. We have analyzed the variable absorption seen in these observations in order to characterize the geometry of the absorbing material. Two of the observations caught NGC 1365 in an unusually low absorption state, revealing complexity in the multi-layer absorber that had previously been hidden. We find the need for three distinct zones of neutral absorption in addition to the two zones of ionized absorption and the Compton-thick torus previously seen in this source. The most prominent absorber is likely associated with broad-line region clouds with column densities of around approximately 10 (sup 23) per square centimeter and a highly clumpy nature as evidenced by an occultation event in 2013 February. We also find evidence of a patchy absorber with a variable column around approximately 10 (sup 22) per square centimeter and a line-of-sight covering fraction of 0.3-0.9, which responds directly to the intrinsic source flux, possibly due to a wind geometry. A full-covering, constant absorber with a low column density of approximately 1 by 10 (sup 22) per square centimeter is also present, though the location of this low density haze is unknown.

  18. The Multi-layer Variable Absorbers in NGC 1365 Revealed by XMM-Newton and NuSTAR

    NASA Astrophysics Data System (ADS)

    Rivers, E.; Risaliti, G.; Walton, D. J.; Harrison, F.; Arévalo, P.; Baur, F. E.; Boggs, S. E.; Brenneman, L. W.; Brightman, M.; Christensen, F. E.; Craig, W. W.; Fürst, F.; Hailey, C. J.; Hickox, R. C.; Marinucci, A.; Reeves, J.; Stern, D.; Zhang, W. W.

    2015-05-01

    Between 2012 July and 2013 February, NuSTAR and XMM-Newton performed four long-look joint observations of the type 1.8 Seyfert, NGC 1365. We have analyzed the variable absorption seen in these observations in order to characterize the geometry of the absorbing material. Two of the observations caught NGC 1365 in an unusually low absorption state, revealing complexity in the multi-layer absorber that had previously been hidden. We find the need for three distinct zones of neutral absorption in addition to the two zones of ionized absorption and the Compton-thick torus previously seen in this source. The most prominent absorber is likely associated with broad-line region clouds with column densities of around ˜1023 cm-2 and a highly clumpy nature as evidenced by an occultation event in 2013 February. We also find evidence of a patchy absorber with a variable column around ˜1022 cm-2 and a line-of-sight covering fraction of 0.3-0.9, which responds directly to the intrinsic source flux, possibly due to a wind geometry. A full-covering, constant absorber with a low column density of ˜1 × 1022 cm-2 is also present, though the location of this low density haze is unknown.

  19. Accessible solitons of fractional dimension

    SciTech Connect

    Zhong, Wei-Ping; Belić, Milivoj; Zhang, Yiqi

    2016-05-15

    We demonstrate that accessible solitons described by an extended Schrödinger equation with the Laplacian of fractional dimension can exist in strongly nonlocal nonlinear media. The soliton solutions of the model are constructed by two special functions, the associated Legendre polynomials and the Laguerre polynomials in the fraction-dimensional space. Our results show that these fractional accessible solitons form a soliton family which includes crescent solitons, and asymmetric single-layer and multi-layer necklace solitons. -- Highlights: •Analytic solutions of a fractional Schrödinger equation are obtained. •The solutions are produced by means of self-similar method applied to the fractional Schrödinger equation with parabolic potential. •The fractional accessible solitons form crescent, asymmetric single-layer and multilayer necklace profiles. •The model applies to the propagation of optical pulses in strongly nonlocal nonlinear media.

  20. Trigonometric Integrals via Partial Fractions

    ERIC Educational Resources Information Center

    Chen, H.; Fulford, M.

    2005-01-01

    Parametric differentiation is used to derive the partial fractions decompositions of certain rational functions. Those decompositions enable us to integrate some new combinations of trigonometric functions.

  1. Fractional-time quantum dynamics.

    PubMed

    Iomin, Alexander

    2009-08-01

    Application of the fractional calculus to quantum processes is presented. In particular, the quantum dynamics is considered in the framework of the fractional time Schrödinger equation (SE), which differs from the standard SE by the fractional time derivative: partial differential/partial differentialt --> partial differential(alpha)/partial differentialt(alpha). It is shown that for alpha=1/2 the fractional SE is isospectral to a comb model. An analytical expression for the Green's functions of the systems are obtained. The semiclassical limit is discussed.

  2. Average time spent by Lévy flights and walks on an interval with absorbing boundaries.

    PubMed

    Buldyrev, S V; Havlin, S; Kazakov, A Y; da Luz, M G; Raposo, E P; Stanley, H E; Viswanathan, G M

    2001-10-01

    We consider a Lévy flyer of order alpha that starts from a point x(0) on an interval [O,L] with absorbing boundaries. We find a closed-form expression for the average number of flights the flyer takes and the total length of the flights it travels before it is absorbed. These two quantities are equivalent to the mean first passage times for Lévy flights and Lévy walks, respectively. Using fractional differential equations with a Riesz kernel, we find exact analytical expressions for both quantities in the continuous limit. We show that numerical solutions for the discrete Lévy processes converge to the continuous approximations in all cases except the case of alpha-->2, and the cases of x(0)-->0 and x(0)-->L. For alpha>2, when the second moment of the flight length distribution exists, our result is replaced by known results of classical diffusion. We show that if x(0) is placed in the vicinity of absorbing boundaries, the average total length has a minimum at alpha=1, corresponding to the Cauchy distribution. We discuss the relevance of this result to the problem of foraging, which has received recent attention in the statistical physics literature.

  3. Ultraviolet absorbance as a proxy for total dissolved mercury in streams

    USGS Publications Warehouse

    Dittman, J.A.; Shanley, J.B.; Driscoll, C.T.; Aiken, G.R.; Chalmers, A.T.; Towse, J.E.

    2009-01-01

    Stream water samples were collected over a range of hydrologic and seasonal conditions at three forested watersheds in the northeastern USA. Samples were analyzed for dissolved total mercury (THgd), DOC concentration and DOC composition, and UV254 absorbance across the three sites over different seasons and flow conditions. Pooling data from all sites, we found a strong positive correlation of THgd to DOC (r2 = 0.87), but progressively stronger correlations of THgd with the hydrophobic acid fraction (HPOA) of DOC (r2 = 0.91) and with UV254 absorbance (r2 = 0.92). The strength of the UV254 absorbance-THgd relationship suggests that optical properties associated with dissolved organic matter may be excellent proxies for THgd concentration in these streams. Ease of sample collection and analysis, the potential application of in-situ optical sensors, and the possibility for intensive monitoring over the hydrograph make this an effective, inexpensive approach to estimate THgd flux in drainage waters. ?? 2009 Elsevier Ltd.

  4. A variable passive low-frequency absorber

    NASA Astrophysics Data System (ADS)

    Larsen, Niels Werner; Thompson, Eric R.; Gade, Anders Christian

    2005-04-01

    Multi-purpose concert halls face a dilemma. They can host classical music concerts, rock concerts and spoken word performances in a matter of a short period. These different performance types require significantly different acoustic conditions in order to provide the best sound quality to both the performers and the audience. A recommended reverberation time for classical music may be in the range of 1.5-2 s for empty halls, where rock music sounds best with a reverberation time around 0.8-1 s. Modern rhythmic music often contains high levels of sound energy in the low frequency bands but still requires a high definition for good sound quality. Ideally, the absorption of the hall should be adjustable in all frequency bands in order to provide good sound quality for all types of performances. The mid and high frequency absorption is easily regulated, but adjusting the low-frequency absorption has typically been too expensive or requires too much space to be practical for multi-purpose halls. Measurements were made on a variable low-frequency absorber to develop a practical solution to the dilemma. The paper will present the results of the measurements as well as a possible design.

  5. Improvement of Absorber's Performance by a Surfactant

    NASA Astrophysics Data System (ADS)

    Nishimura, Nobuya; Nomura, Tomohiro; Iyota, Hiroyuki; Kawakami, Ryuichiro

    Effects of an addition of surfactant to a lithium bromide aqueous solution have been investigated experimentally. N-octanol was used as a surfactant. The Marangoni convection occurred at/beneath the solution surface in the very beginning of steam absorption was observed both by a real-time type laser holographic visualization and by temperature measurements with extremely fine gauge thermocouples. Generation and growth of the Marangoni convection were both observed and evaluated quantitatively by the flow visualization. Furthermore, solution's surface temperatures with and without addition of the surfactant were measured minutely. Cell's formation pattern and migration speed at the surface were measured varying the initial surfactant's concentration ranging from 0 to 50000 ppm and the shallow liquid layer thickness ranging from 2 to 5 mm. And spacio-temporal scales of the Marangoni convection were determined. Also solution temperature changes at the surface were compared. Temperature increases when the surfactant was added to its solubility limit became almost double than that case of no surfactant. From these temperature differences, effects of the surfactant on absorber's performances were estimated by a calculation quantitatively with diffusion coefficient as an evaluation value.

  6. Transient QED effects in absorbing dielectrics

    NASA Astrophysics Data System (ADS)

    Wubs, Martijn; Suttorp, L. G.

    2001-04-01

    The spontaneous-emission rate of a radiating atom reaches its time-independent equilibrium value after an initial transient regime. In this paper, we consider the associated relaxation effects of the spontaneous-decay rate of atoms in dispersive and absorbing dielectric media for atomic-transition frequencies near material resonances. A quantum mechanical description of such media is furnished by a damped-polariton model in which absorption is taken into account through coupling to a bath. We show how all field and matter operators in this theory can be expressed in terms of the bath operators at an initial time. The consistency of these solutions for the field and matter operators are found to depend on the validity of certain velocity sum rules. The transient effects in the spontaneous-decay rate are studied with the help of several specific models for the dielectric constant, which are shown to follow from the general theory by adopting particular forms of the bath coupling constant.

  7. Space Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Stephan, Ryan; Hodgson, Ed; Izenson, Mike; Chen, Weibo

    2012-01-01

    A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA s Spacesuit Water Membrane Evaporator (SWME), and Creare s flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 m2 radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduces the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.

  8. Multifunctional Space Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Hodgson, Ed; Izenson, Mike; Chen, Weibo

    2013-01-01

    A system for non-venting thermal control for spacesuits was built by integrating two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's flexible version of the Lithium Chloride Absorber Radiator (LCAR). This SEAR system was tested in relevant thermal vacuum conditions. These tests show that a 1 sq m radiator having about three times as much absorption media as in the test article would be required to support a 7 hour spacewalk. The serial flow arrangement of the LCAR of the flexible version proved to be inefficient for venting non-condensable gas (NCG). A different LCAR packaging arrangement was conceived wherein the Portable Life Support System (PLSS) housing would be made with a high-strength carbon fiber composite honeycomb, the cells of which would be filled with the chemical absorption media. This new packaging reduce the mass and volume impact of the SEAR on the Portable Life Support System (PLSS) compared to the flexible design. A 0.2 sq m panel with flight-like honeycomb geometry is being constructed and will be tested in thermal and thermal vacuum conditions. Design analyses forecast improved system performance and improved NCG control. A flight-like regeneration system also is also being built and tested. Design analyses for the structurally integrated prototype as well as the earlier test data show that SEAR is not only practical for spacesuits but also has useful applications in spacecraft thermal control.

  9. Spacesuit Evaporator-Absorber-Radiator (SEAR)

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Hodgson, Ed; Izenso, Mike; Chan, Weibo; Cupples, Scott

    2011-01-01

    For decades advanced spacesuit developers have pursued a regenerable, robust non-venting system for heat rejection. Toward this end, this paper investigates linking together two previously developed technologies, namely NASA's Spacesuit Water Membrane Evaporator (SWME), and Creare's lithium chloride Heat Pump Radiator (HPR). Heat from a liquid cooled garment is transported to SWME that provides cooling through evaporation. The SEAR is evacuated at the onset of operations and thereafter, the water vapor absorption rate of the HPR maintains a low pressure environment for the SWME to evaporate effectively. This water vapor captured by solid LiCl in the HPR with a high enthalpy of absorption, results in sufficient temperature lift to reject most of the heat to space by radiation. After the sortie, the HPR would be heated up in a regenerator to drive off and recover the absorbed evaporant. A one-fourth scale prototype was built and tested in vacuum conditions at a sink temperature of 250 K. The HPR was able to stably reject 60 W over a 7-hour period. A conceptual design of a full-scale radiator is proposed. Excess heat rejection above 240 W would be accomplished through venting of the evaporant. Loop closure rates were predicted for various exploration environment scenarios.

  10. Semiconductor nanowire optical antenna solar absorbers.

    PubMed

    Cao, Linyou; Fan, Pengyu; Vasudev, Alok P; White, Justin S; Yu, Zongfu; Cai, Wenshan; Schuller, Jon A; Fan, Shanhui; Brongersma, Mark L

    2010-02-10

    Photovoltaic (PV) cells can serve as a virtually unlimited clean source of energy by converting sunlight into electrical power. Their importance is reflected in the tireless efforts that have been devoted to improving the electrical and structural properties of PV materials. More recently, photon management (PM) has emerged as a powerful additional means to boost energy conversion efficiencies. Here, we demonstrate an entirely new PM strategy that capitalizes on strong broad band optical antenna effects in one-dimensional semiconductor nanostructures to dramatically enhance absorption of sunlight. We show that the absorption of sunlight in Si nanowires (Si NWs) can be significantly enhanced over the bulk. The NW's optical properties also naturally give rise to an improved angular response. We propose that by patterning the silicon layer in a thin film PV cell into an array of NWs, one can boost the absorption for solar radiation by 25% while utilizing less than half of the semiconductor material (250% increase in the light absorption per unit volume of material). These results significantly advance our understanding of the way sunlight is absorbed by one-dimensional semiconductor nanostructures and provide a clear, intuitive guidance for the design of efficient NW solar cells. The presented approach is universal to any semiconductor and a wide range of nanostructures; as such, it provides a new PV platform technology.

  11. Design of a multiband terahertz perfect absorber

    NASA Astrophysics Data System (ADS)

    Dan, Hu; Hong-yan, Wang; Zhen-jie, Tang; Xi-wei, Zhang; Lin, Ju; Hua-ying, Wang

    2016-03-01

    A thin-flexible multiband terahertz metamaterial absorber (MA) has been investigated. Each unit cell of the MA consists of a simple metal structure, which includes the top metal resonator ring and the bottom metallic ground plane, separated by a thin-flexible dielectric spacer. Finite-difference time domain simulation indicates that this MA can achieve over 99% absorption at frequencies of 1.50 THz, 3.33 THz, and 5.40 THz by properly assembling the sandwiched structure. However, because of its asymmetric structure, the MA is polarization-sensitive and can tune the absorptivity of the second absorption peak by changing the incident polarization angle. The effect of the error of the structural parameters on the absorption efficiency is also carefully analyzed in detail to guide the fabrication. Moreover, the proposed MA exhibits high refractive-index sensing sensitivity, which has potential applications in multi-wavelength sensing in the terahertz region. Project supported by the National Natural Science Foundation of China (Grant No. 11504006), the Key Scientific Research Project of Higher Education of Henan Province, China (Grant No. 15A140002), and the Science and Technology Planning Project of Henan Province, China (Grant No. 142300410366).

  12. [Surgery of Lower Eyelid Ectropion with the Tarsal Strip Procedure, Using Absorbable or Non-Absorbable Sutures for Periosteal Fixation].

    PubMed

    Sommer, F

    2017-01-01

    Purpose Tightening of the lower eyelid is often performed and many techniques are available. This paper describes the outcome of lower eyelid ectropion repair using the lateral tarsal strip procedure. Periosteal fixation of the tarsal strip can be performed with absorbable or non-absorbable sutures. This study compares the surgical results of periosteal fixation of the tarsal strip with a) absorbable and b) non-absorbable suture. Methods Of 206 patients who underwent surgery, data from 161 were available. During the 6 month follow-up period, suture material, recurrence rates and complications were assessed. The analysis was based on photo documentation, surgery reports and patient statements. In all cases surgery was performed by the same surgeon. Results After 6 months, patients showed similar recurrence rates, regardless of whether periosteal fixation of the tarsal strip had been performed with absorbable (61 patients) or non-absorbable (100 patients) material. Only a few complications occurred, including wound healing problems and one allergic reaction in the non-absorbable group. Conclusions In cases of lower eyelid ectropion, the surgical outcome after the tarsal strip procedure was similar for absorbable and non-absorbable sutures.

  13. Effect of the bio-absorbent on the microwave absorption property of the flaky CIPs/rubber absorbers

    NASA Astrophysics Data System (ADS)

    Cheng, Yang; Xu, Yonggang; Cai, Jun; Yuan, Liming; Zhang, Deyuan

    2015-09-01

    Microwave absorbing composites filled with flaky carbonyl iron particles (CIPs) and the bio-absorbent were prepared by using a two-roll mixer and a vulcanizing machine. The electromagnetic (EM) parameters were measured by a vector network analyzer and the reflection loss (RL) was measured by the arch method in the frequency range of 1-4 GHz. The uniform dispersion of the absorbents was verified by comparing the calculated RL with the measured one. The results confirm that as the bio-absorbent was added, the permittivity was increased due to the volume content of absorbents, and the permeability was enlarged owing to the volume content of CIPs and interactions between the two absorbents. The composite filled with bio-absorbents achieved an excellent absorption property at a thickness of 1 mm (minimum RL reaches -7.8 dB), and as the RL was less than -10 dB the absorption band was widest (2.1-3.8 GHz) at a thickness of 2 mm. Therefore, the bio-absorbent is a promising additive candidate on fabricating microwave absorbing composites with a thinner thickness and wider absorption band.

  14. MoSi absorber photomask for 32nm node

    NASA Astrophysics Data System (ADS)

    Konishi, Toshio; Kojima, Yosuke; Takahashi, Hiroyuki; Tanabe, Masato; Haraguchi, Takashi; Lamantia, Matthew; Fukushima, Yuichi; Okuda, Yoshimitsu

    2008-05-01

    The development of semiconductor process for 32nm node is in progress. Immersion lithography has been introduced as an extension of 193nm lithograpy. In addition, DPL (Double patterning lithography) is becoming a strong candidate of next generation lithography. The extension of optical lithography increases more mask complexity and tighter specification of photomasks. CD performance is the most important issue in the advanced photomask technology. However, it is expected that conventional mask cannot satisfy the required mask specifications for 32nm node and beyond. Most of CD errors are contributed to the dry etching process. Mask CD variation is greatly influenced by the loading effect from dry etching of the absorber. As the required accuracy of the mask arises, Cr absorber thickness has been gradually thinner. CD linearity with the thinner Cr absorber thickness has better performance. However, it is difficult to apply thinner Cr absorber thickness simply under the condition of OD > 3, which is needed for wafer printing. So, we adopted MoSi absorber instead of conventional Cr absorber, because MoSi absorber has less micro and global loading effect than that of Cr absorber. By using MoSi absorber, we can reduce Cr thickness as a hardmask. The thinner Cr hardmask allows for reduce resist thickness and become same condition for conventional EB resist lithography. The lithography performances were confirmed by the simulation and wafer printing. The new MoSi absorber mask behaves similar to the conventional Cr absorber mask. The adoption of super thin Cr as a hardmask made it possible to reduce resist thickness. By the application of the thin resist and the latest tools, we'll improve the mask performance to meet the 32 nm generation specification.

  15. In vitro performance of prefilled CO₂ absorbers with the Aisys®.

    PubMed

    Hendrickx, Jan F A; De Ridder, Simon P A J; Dehouwer, Alexander; Carette, Rik; De Cooman, Sofie; De Wolf, Andre M

    2016-04-01

    Low flow anesthesia increases the use of CO2 absorbents, but independent data that compare canister life of the newest CO2 absorbents are scarce. Seven different pre-packed CO2 canisters were tested in vitro: Amsorb Plus, Spherasorb, LoFloSorb, Medisorb, Medisorb EF, LithoLyme, and SpiraLith. CO2 (160 mL min(-1)) flowed into the tip of a 2 L breathing bag that was ventilated with a tidal volume of 500 mL, a respiratory rate of 10/min, and an I:E ratio of 1:1 using the controlled mechanical ventilation mode of the Aisys (®) (GE, Madison, WI, USA). In part I, canister life of each brand (all of the same lot) was tested with 12 different fresh gas flows (FGF) ranging from 0.25 to 4 L min(-1). In part II, canister life of six canisters each of two different lots of each brand were tested with a 350 mL min(-1) FGF. Canister life is presented as "FCU", fractional canister usage, the fraction of a canister used per hour, and is defined for the inspired CO2 concentration (FICO2) that denotes exhaustion. In part III, canister life per 100 g fresh granule content was calculated. FCU decreased linearly with increasing FGF. The relative position of the FCU-FGF curves of the different brands depends on the FICO2 threshold because the exhaustion rate (the rate of rise once FICO2 starts to increase) differs among the brands. Intra-lot variability was 18 % or less. The different prepacks can be ranked according their efficiency (least to most efficient) as follows: Amsorb Plus = Medisorb EF < LoFloSorb < Medisorb = Spherasorb = LithoLyme < SpiraLith (all for an FICO2 threshold = 0.5 %). Canister life per 100 g fresh granule content is almost twice as long when LiOH is used as the primary absorbent. The most important factors that determine canister life of prepacks in a circle breathing system are the chemical composition of the canister, the absolute amount of absorbent present in the canister, and the FICO2 replacement threshold. The use of the fractional canister usage allows

  16. Fractional random walk lattice dynamics

    NASA Astrophysics Data System (ADS)

    Michelitsch, T. M.; Collet, B. A.; Riascos, A. P.; Nowakowski, A. F.; Nicolleau, F. C. G. A.

    2017-02-01

    We analyze time-discrete and time-continuous ‘fractional’ random walks on undirected regular networks with special focus on cubic periodic lattices in n  =  1, 2, 3,.. dimensions. The fractional random walk dynamics is governed by a master equation involving fractional powers of Laplacian matrices {{L}\\fracα{2}}} where α =2 recovers the normal walk. First we demonstrate that the interval 0<α ≤slant 2 is admissible for the fractional random walk. We derive analytical expressions for the transition matrix of the fractional random walk and closely related the average return probabilities. We further obtain the fundamental matrix {{Z}(α )} , and the mean relaxation time (Kemeny constant) for the fractional random walk. The representation for the fundamental matrix {{Z}(α )} relates fractional random walks with normal random walks. We show that the matrix elements of the transition matrix of the fractional random walk exihibit for large cubic n-dimensional lattices a power law decay of an n-dimensional infinite space Riesz fractional derivative type indicating emergence of Lévy flights. As a further footprint of Lévy flights in the n-dimensional space, the transition matrix and return probabilities of the fractional random walk are dominated for large times t by slowly relaxing long-wave modes leading to a characteristic {{t}-\\frac{n{α}} -decay. It can be concluded that, due to long range moves of fractional random walk, a small world property is emerging increasing the efficiency to explore the lattice when instead of a normal random walk a fractional random walk is chosen.

  17. The neutral gas extent of galaxies as derived from weak intervening Ca ii absorbers

    NASA Astrophysics Data System (ADS)

    Richter, P.; Krause, F.; Fechner, C.; Charlton, J. C.; Murphy, M. T.

    2011-04-01

    We present a systematic study of weak intervening Ca ii absorbers at low redshift (z < 0.5), based on the analysis of archival high-resolution (R ≥ 45 000) optical spectra of 304 quasars and active galactic nuclei observed with VLT/UVES. Along a total redshift path of Δz ≈ 100 we detected 23 intervening Ca ii absorbers in both the Ca ii H & K lines, with rest frame equivalent widths Wr,3934 = 15-799 mÅ and column densities log N(Ca ii) = 11.25-13.04 (obtained by fitting Voigt-profile components). We obtain a bias-corrected number density of weak intervening Ca ii absorbers of {d{N}/dz=0.117 ± 0.044} at ⟨zabs⟩ = 0.35 for absorbers with log N(Ca ii) ≥ 11.65 (Wr,3934 ≥ 32 mÅ). This is 2.6 times the value obtained for damped Lyman α absorbers (DLAs) at low redshift. All Ca ii absorbers in our sample show associated absorption by other low ions such as Mg ii and Fe ii; 45 percent of them have associated Na i absorption. From ionization modelling we conclude that intervening Ca ii absorption with log N(Ca ii) ≥ 11.5 arises in DLAs, sub-DLAs and Lyman-limit systems (LLS) at H i column densities of log N(H i) ≥ 17.4. Using supplementary H i information for nine of the absorbers we find that the Ca ii/H i ratio decreases strongly with increasing H i column density, indicating a column-density-dependent dust depletion of Ca. The observed column density distribution function of Ca ii absorption components follows a relatively steep power law, f(N) ∝ N - β, with a slope of - β = -1.68, which again points towards an enhanced dust depletion in high column density systems. The relatively large cross section of these absorbers together with the frequent detection of Ca ii absorption in high-velocity clouds (HVCs) in the halo of the Milky Way suggests that a considerable fraction of the intervening Ca ii systems trace (partly) neutral gas structures in the halos and circumgalactic environment of galaxies (i.e., they are HVC analogs). Based on the recently

  18. The NuSTAR View of Reflecting and Absorbing Circumnuclear Material in AGN

    NASA Astrophysics Data System (ADS)

    Rivers, Elizabeth

    2016-04-01

    The physical conditions and precise geometry of the accreting circumnuclear material in the vicinity of supermassive black holes remain open and critical questions. Between July 2012 and February 2013, NuSTAR and XMM-Newton performed four long-look joint observations of the type 1.8 Seyfert, NGC 1365. We have analyzed the variable absorption seen in these observations in order to characterize the geometry of the absorbing material. Two of the observations caught NGC 1365 in an unusually low absorption state, revealing complexity in the multi-layer absorbers which had previously been hidden, including a the Compton-thick torus, BLR clouds, and a patchy absorber with a variable column around 1022 cm-2 and a line of sight covering fraction of 0.3-0.9 which responds directly to the intrinsic source flux, possibly due to a wind geometry. We have also analyzed two NuSTAR observations of NGC 7582, a well-studied X-ray bright Seyfert 2 with moderately heavy highly variable absorption and strong reflection spectral features. Changes in the spectral shape and high reflection fractions have led to competing explanations: 1) the central X-ray source partially “shut off”, decreasing in intrinsic luminosity, with a delayed decrease in reflection features due to the light-crossing time of the Compton-thick material or 2) the source became more heavily obscured, with only a portion of the power law continuum leaking through. The high quality of the NuSTAR spectra above 10 keV give us the best look at the reflection hump to date and allow us to test these two scenarios.

  19. Microwave Absorbing Properties of Metallic Glass/Polymer Composites

    DTIC Science & Technology

    2011-09-01

    Technical Report ARWSB-TR-11022 Microwave Absorbing Properties of Metallic Glass/Polymer Composites Stephen Bartolucci...Technical 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Microwave Absorbing Properties of Metallic Glass/Polymer Composites 5a. CONTRACT...this study, the microwave absorption characteristics of metallic glass / polymer composites were investigated. Electromagnetic wave absorption

  20. Shock-absorbing caster wheel is simple and compact

    NASA Technical Reports Server (NTRS)

    Kindley, R. J.

    1968-01-01

    Compact shock-absorbing caster wheel mitigates or absorbs shock by a compressible tire which deforms into a cavity between its inner edge and the wheel hub. A tee-shaped annular ring embedded in the tire distributes loads more uniformly throughout both wheel and tire.

  1. Science on a Roll. Part One: Absorbing Inquiry.

    ERIC Educational Resources Information Center

    Brendzel, Sharon

    2002-01-01

    Presents an activity that tests the absorbency of different brands of paper towels. Suggests making this activity into an open-ended inquiry type of activity. Includes sample questions to guide students, topics for class discussion, and sample methods of using the absorbency activity. (KHR)

  2. Performance of an artificial absorber for truncating FEM meshes

    NASA Astrophysics Data System (ADS)

    Gong, Jian; Volakis, John L.

    1995-01-01

    We investigate the effectiveness of an artificial absorber for truncating finite element (FE) meshes. Specifically, we present the implementation of a novel mesh truncation approach using a perfectly matched anisotropic absorber for waveguides and stripline circuits. This truncation scheme is useful in many applications, including antennas, scattering, and microwave circuits.

  3. Physically absorbable reagents-collectors in elementary flotation

    SciTech Connect

    S.A. Kondrat'ev; I.G. Bochkarev

    2007-09-15

    Based on the reviewed researches held at the Institute of Mining, Siberian Branch, Russian Academy of Sciences, the effect of physically absorbable reagents-collectors on formation of a flotation complex and its stability in turbulent pulp flows in flotation machines of basic types is considered. The basic requirements for physically absorbable reagents-collectors at different flotation stages are established.

  4. An Absorbing Look at Terry-Cloth Towels

    ERIC Educational Resources Information Center

    Moyer, Richard; Everett, Susan

    2010-01-01

    This article describes a lesson where students explore the absorbency of several towels with different weaves and weights. The lesson follows the 5E learning-cycle model and incorporates engineering in the sense of product testing with a focus on the relationship between the weave of a towel and its absorbency. The National Science Education…

  5. 14 CFR 27.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Tires and shock absorbers. 27.475 Section... be in their static position and the shock absorbers to be in their most critical position. ... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Ground Loads § 27.475 Tires and...

  6. 14 CFR 27.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Tires and shock absorbers. 27.475 Section... be in their static position and the shock absorbers to be in their most critical position. ... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Ground Loads § 27.475 Tires and...

  7. 14 CFR 27.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Tires and shock absorbers. 27.475 Section... be in their static position and the shock absorbers to be in their most critical position. ... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Ground Loads § 27.475 Tires and...

  8. 14 CFR 27.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Tires and shock absorbers. 27.475 Section... be in their static position and the shock absorbers to be in their most critical position. ... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Ground Loads § 27.475 Tires and...

  9. 14 CFR 27.475 - Tires and shock absorbers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Tires and shock absorbers. 27.475 Section... be in their static position and the shock absorbers to be in their most critical position. ... AIRWORTHINESS STANDARDS: NORMAL CATEGORY ROTORCRAFT Strength Requirements Ground Loads § 27.475 Tires and...

  10. Nylon shock absorber prevents injury to parachute jumpers

    NASA Technical Reports Server (NTRS)

    Mandel, J. A.

    1966-01-01

    Nylon shock absorbers reduce the canopy-opening shock of a parachute to a level that protects the wearer from injury. A shock absorber is mounted on each of the four risers between the shroud lines and the harness. Because of their size and location, they pose no problem in repacking the chute and harness after a jump.

  11. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Absorbable implant (scleral buckling method). 886.3300 Section 886.3300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling method) is a...

  12. 21 CFR 886.3300 - Absorbable implant (scleral buckling method).

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Absorbable implant (scleral buckling method). 886.3300 Section 886.3300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... (scleral buckling method). (a) Identification. An absorbable implant (scleral buckling method) is a...

  13. Photochromic And Thermochromic Pigments For Solar Absorbing-Reflecting Coatings

    NASA Astrophysics Data System (ADS)

    Novinson, Thomas

    1987-11-01

    Both photochromic and thermochromic compounds were synthesized and physical measurements were made to determine coefficients of relectance, absorbance and emission. The most interesting group of thermochromic compounds are related to silver tctraiodomercurate and the most interesting photochromic compounds are substituted benzoindolinopyrospirans. The synthesis and optical reflectance and absorbance properties of other classes of compounds are also reported.

  14. 21 CFR 880.5300 - Medical absorbent fiber.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... and that is used for applying medication to, or absorbing small amounts of body fluids from, a patient's body surface. Absorbent fibers intended solely for cosmetic purposes are not included in...

  15. 21 CFR 880.5300 - Medical absorbent fiber.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... and that is used for applying medication to, or absorbing small amounts of body fluids from, a patient's body surface. Absorbent fibers intended solely for cosmetic purposes are not included in...

  16. A molecular fraction method for measuring personnel radiation doses

    NASA Astrophysics Data System (ADS)

    Fadel, M. A.; Khalil, W. A.; Krodja, R. P.; Sheta, N.; Abd El-Baset, M. S.

    1987-02-01

    This work represents a development in fast and albedo neutron and gamma ray dosimetry, using cellulose nitrate, as a tissue equivalent material, in which radiation damage was registered. The changes in molecular fractions of the polymer were measured after irradiation with neutron fluences from a 252Cf source in the range 10 5-10 10 n/cm 2 and gamma doses in the range 10 -4-10 -1 Gy through the use of gel filtration chromatography. Effects of irradiation on phantom, phantom to dosimeter distance, phantom thickness and storage at extreme environmental conditions were studied on the detector response and readout. The results showed that main chain scission followed by formation of new molecular configurations is the predominant effect of radiation on the polymer. The method enables measurements of neutron fluences and gamma doses in mixed radiation fields. Empirical formulae for calculating the absorbed dose from the measured changes in molecular fraction intensities are given.

  17. Unwrapping Students' Ideas about Fractions

    ERIC Educational Resources Information Center

    Lewis, Rebecca M.; Gibbons, Lynsey K.; Kazemi, Elham; Lind, Teresa

    2015-01-01

    Supporting students to develop an understanding of the meaning of fractions is an important goal of elementary school mathematics. This involves developing partitioning strategies, creating representations, naming fractional quantities, and using symbolic notation. This article describes how teachers can use a formative assessment problem to…

  18. Rational Exponentials and Continued Fractions

    ERIC Educational Resources Information Center

    Denny, J. K.

    2012-01-01

    Using continued fraction expansions, we can approximate constants, such as pi and e, using an appropriate integer n raised to the power x[superscript 1/x], x a suitable rational. We review continued fractions and give an algorithm for producing these approximations.

  19. Understanding Magnitudes to Understand Fractions

    ERIC Educational Resources Information Center

    Gabriel, Florence

    2016-01-01

    Fractions are known to be difficult to learn and difficult to teach, yet they are vital for students to have access to further mathematical concepts. This article uses evidence to support teachers employing teaching methods that focus on the conceptual understanding of the magnitude of fractions.

  20. HST/COS observations of a new population of associated QSO absorbers

    NASA Astrophysics Data System (ADS)

    Muzahid, S.; Srianand, R.; Arav, N.; Savage, B. D.; Narayanan, A.

    2013-05-01

    We present a sample of new population of associated absorbers, detected through Ne VIII λλ770, 780 absorption, in the Hubble Space Telescope (HST)/Cosmic Origins Spectrograph (COS) spectra of intermediate-redshift (0.45 < z < 1.21) quasars (QSOs). Our sample comprised of total 12 associated Ne VIII systems detected towards eight lines of sight (none of them are radio bright). The incidence rate of these absorbers is found to be 40 per cent. Majority of the Ne VIII systems at small ejection velocities (vej) show complete coverage of the background source, but systems with higher vej show lower covering fractions (i.e. fc ≤ 0.8) and systematically higher values of N({Ne VIII}). We detect Mg X λλ609, 624 absorption in seven out of the eight Ne VIII systems where the expected wavelength range is covered by our spectra and is free of any strong blending. We report the detections of Na IX λλ681, 694 absorption, for the first time, in three highest ejection velocity (e.g. |vej| ≳ 7000 km s-1) systems in our sample. All these systems show very high N({Ne VIII}) (i.e. >1015.6 cm-2), high ionization parameter (i.e. log U ≳ 0.5), high metallicity (i.e. Z ≳ Z⊙) and ionization-potential-dependent fc values. The observed column density ratios of different ions are reproduced by multiphase photoionization (PI) and/or collisional ionization (CI) equilibrium models. While solar abundance ratios are adequate in CIE, enhancement of Na relative to Mg is required in PI models to explain our observations. The column density ratios of highly ionized species (i.e. O VI, Ne VIII, Mg X, etc.) show a very narrow spread. Moreover, the measured N({Ne VIII})/N({O VI}) ratio in the associated absorbers is similar to what is seen in the intervening absorbers. All these suggest a narrow range of ionization parameter in the case of PI or a narrow temperature range (i.e. T ˜ 105.9±0.1 K) in the case of CIE models. The present data do not distinguish between these two alternatives