WorldWideScience

Sample records for absorption

  1. Narrative absorption

    DEFF Research Database (Denmark)

    Narrative Absorption brings together research from the social sciences and Humanities to solve a number of mysteries: Most of us will have had those moments, of being totally absorbed in a book, a movie, or computer game. Typically we do not have any idea about how we ended up in such a state. No...

  2. D-xylose absorption

    Science.gov (United States)

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

  3. [Study on lead absorption in pumpkin by atomic absorption spectrophotometry].

    Science.gov (United States)

    Li, Zhen-Xia; Sun, Yong-Dong; Chen, Bi-Hua; Li, Xin-Zheng

    2008-07-01

    A study was carried out on the characteristic of lead absorption in pumpkin via atomic absorption spectrophotometer. The results showed that lead absorption amount in pumpkin increased with time, but the absorption rate decreased with time; And the lead absorption amount reached the peak in pH 7. Lead and cadmium have similar characteristic of absorption in pumpkin.

  4. Membrane Gas Absorption

    NARCIS (Netherlands)

    Jansen, A.E.; Klaassen, R.; Feron, P.H.M.

    1995-01-01

    Membrane gas absorption processes are absorption processes utilising hollow fibre membranes as contacting media for gas and liquid flows. The principle of operation and engineering aspects are discussed, followed by discussion of a number of typical applications. Benefits in terms of operation,

  5. Nutrition and magnesium absorption

    NARCIS (Netherlands)

    Brink, E.J.

    1992-01-01

    The influence of various nutrients present in dairy products and soybean-based products on absorption of magnesium has been investigated. The studies demonstrate that soybean protein versus casein lowers apparent magnesium absorption in rats through its phytate component. However, true

  6. Solar absorption surface panel

    Science.gov (United States)

    Santala, Teuvo J.

    1978-01-01

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

  7. Zeeman atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Hadeishi, T.; McLaughlin, R.

    1978-08-01

    The design and development of a Zeeman atomic absorption spectrometer for trace element analysis are described. An instruction manual is included which details the operation, adjustment, and maintenance. Specifications and circuit diagrams are given. (WHK)

  8. Absorption heat pump system

    Science.gov (United States)

    Grossman, Gershon

    1984-01-01

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

  9. Optical absorption measurement system

    Science.gov (United States)

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

    1989-01-01

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

  10. Absorption cooling device. Absorptions-Kuehlvorrichtung

    Energy Technology Data Exchange (ETDEWEB)

    Bourne, J.; Vardi, I.; Kimchi, Y.; Ben-Dror, J.

    1980-03-25

    The invention concerns improvements of absorption refrigerators, where a lithium chloride or lithium bromide/water cycle is used. According to the invention an inner separating or dividing structure between different functional parts of a machine of this type is provided. The structure contains two sections of wall, which are separated from one another by a suitable space, in order to achieve thermal insulation. This air space is provided with an opening in the direction towards the inside of the container and the opening is shielded to prevent the entry of liquids (in liquid or spray form).

  11. Central cooling: absorptive chillers

    Energy Technology Data Exchange (ETDEWEB)

    Christian, J.E.

    1977-08-01

    This technology evaluation covers commercially available single-effect, lithium-bromide absorption chillers ranging in nominal cooling capacities of 3 to 1,660 tons and double-effect lithium-bromide chillers from 385 to 1,060 tons. The nominal COP measured at operating conditions of 12 psig input steam for the single-effect machine, 85/sup 0/ entering condenser water, and 44/sup 0/F exiting chilled-water, ranges from 0.6 to 0.65. The nominal COP for the double-effect machine varies from 1.0 to 1.15 with 144 psig entering steam. Data are provided to estimate absorption-chiller performance at off-nominal operating conditions. The part-load performance curves along with cost estimating functions help the system design engineer select absorption equipment for a particular application based on life-cycle costs. Several suggestions are offered which may be useful for interfacing an absorption chiller with the remaining Integrated Community Energy System. The ammonia-water absorption chillers are not considered to be readily available technology for ICES application; therefore, performance and cost data on them are not included in this evaluation.

  12. Absorption heat pump system

    Science.gov (United States)

    Grossman, Gershon; Perez-Blanco, Horacio

    1984-01-01

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

  13. Visual Absorption Capability

    Science.gov (United States)

    Lee Anderson; Jerry Mosier; Geoffrey Chandler

    1979-01-01

    Visual absorption capability (VAC) is a tool to assess a landscape's susceptibility to visual change caused by man's activities. This paper explores different descriptive approaches to VAC and addresses in depth the development of the VAC process used on the Klamath National Forest. Four biophysical factors were selected to assess VAC for the lands within the...

  14. Chemical Absorption Materials

    DEFF Research Database (Denmark)

    Thomsen, Kaj

    2011-01-01

    Chemical absorption materials that potentially can be used for post combustion carbon dioxide capture are discussed. They fall into five groups, alkanolamines, alkali carbonates, ammonia, amino acid salts, and ionic liquids. The chemistry of the materials is discussed and advantages and drawbacks...

  15. Revisiting Absorptive Capacity

    DEFF Research Database (Denmark)

    de Araújo, Ana Luiza Lara; Ulhøi, John Parm; Lettl, Christopher

    Absorptive capacity has mostly been perceived as a 'passive' outcome of R&D investments. Recently, however, a growing interest into its 'proactive' potentials has emerged. This paper taps into this development and proposes a dynamic model for conceptualizing the determinants of the complementary ...... processes, with emphasis on exploitative learning. Before concluding, the paper addresses implications for theory and practice and limitations of this study....

  16. Relic Neutrino Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Eberle, b

    2004-01-28

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

  17. Absorption in periodic layered structures

    OpenAIRE

    Moroz, Alexander; Tip, Adriaan; Combes, Jean-Michel

    2000-01-01

    Photonic band structure of metal-dielectric and semiconductor-dielectric layered structures are studied in the presence of a strong absorption. It is shown that absorption can enlarge some gaps by as much as 50%.

  18. Subgap Absorption in Conjugated Polymers

    Science.gov (United States)

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of fluorination.

  19. Absorption characteristics of bacteriorhodopsin molecules

    Indian Academy of Sciences (India)

    The analytical expression for the absorption coefficient of BR film is applied to study the absorption characteristics of BR molecules in a typical laser system operating at funda- mental wavelength 514 nm. The experimental data available for the absorption coefficients of the levels B and M corresponding to the wavelength ...

  20. Rapidly variable relatvistic absorption

    Science.gov (United States)

    Parker, M.; Pinto, C.; Fabian, A.; Lohfink, A.; Buisson, D.; Alston, W.; Jiang, J.

    2017-10-01

    I will present results from the 1.5Ms XMM-Newton observing campaign on the most X-ray variable AGN, IRAS 13224-3809. We find a series of nine absorption lines with a velocity of 0.24c from an ultra-fast outflow. For the first time, we are able to see extremely rapid variability of the UFO features, and can link this to the X-ray variability from the inner accretion disk. We find a clear flux dependence of the outflow features, suggesting that the wind is ionized by increasing X-ray emission.

  1. Absorption in dielectric models

    CERN Document Server

    Churchill, R J

    2015-01-01

    We develop a classical microscopic model of a dielectric. The model features nonlinear interaction terms between polarizable dipoles and lattice vibrations. The lattice vibrations are found to act as a pseudo-reservoir, giving broadband absorption of electromagnetic radiation without the addition of damping terms in the dynamics. The effective permittivity is calculated using a perturbative iteration method and is found to have the form associated with real dielectrics. Spatial dispersion is naturally included in the model and we also calculate the wavevector dependence of the permittivity.

  2. Geospatial Absorption and Regional Effects

    Directory of Open Access Journals (Sweden)

    IOAN MAC

    2009-01-01

    Full Text Available The geospatial absorptions are characterized by a specific complexity both in content and in their phenomenological and spatial manifestation fields. Such processes are differentiated according to their specificity to pre-absorption, absorption or post-absorption. The mechanisms that contribute to absorption are extremely numerous: aggregation, extension, diffusion, substitution, resistivity (resilience, stratification, borrowings, etc. Between these mechanisms frequent relations are established determining an amplification of the process and of its regional effects. The installation of the geographic osmosis phenomenon in a given territory (a place for example leads to a homogenization of the geospatial state and to the installation of the regional homogeneity.

  3. Sabine absorption coefficients to random incidence absorption coefficients

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2014-01-01

    into random incidence absorption coefficients for porous absorbers are investigated. Two optimization-based conversion methods are suggested: the surface impedance estimation for locally reacting absorbers and the flow resistivity estimation for extendedly reacting absorbers. The suggested conversion methods......Absorption coefficients measured by the chamber method are referred to as Sabine absorption coefficients, which sometimes exceed unity due to the finite size of a specimen and non-uniform intensity in the test chamber. In this study, several methods that convert Sabine absorption coefficients...

  4. X-ray Absorption Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  5. Phytases for improved iron absorption

    DEFF Research Database (Denmark)

    Nielsen, Anne Veller Friis; Meyer, Anne S.

    2016-01-01

    Phytase enzymes present an alternative to iron supplements, because they have been shown to improve iron absorption by means of catalysing the degradation of a potent iron absorption inhibitor: phytic acid. Phytic acid is a hexaphosphate of inositol and is particularly prevalent in cereal grains...

  6. Wave energy absorption by ducks

    DEFF Research Database (Denmark)

    Kurniawan, Adi

    2017-01-01

    We study the absorption of wave energy by a single and multiple cam-shaped bodies referred to as ducks. Numerical models are developed under the assumptions of linear theory. We consider wave absorption by a single duck as well as by two lines of ducks meeting at an angle....

  7. Water absorption in brick masonry

    NARCIS (Netherlands)

    Brocken, H.J.P.; Smolders, H.R.

    1996-01-01

    The water absorption in brick, mortar that was cured separately, and masonry samples was studied using NMR. Models of the moisture transport are usually formulated on the basis of a diffusion equation. In the case of water absorption in separate brick and mortar samples, the moisture diffusivity in

  8. The expected time until absorption when absorption is not certain

    OpenAIRE

    Walker, D. M.

    1998-01-01

    This paper considers continuous-time Markov chains whose state space consists of an irreducible class, , and an absorbing state which is accessible from . The purpose is to provide a way to determine the expected time to absorption conditional on such time being finite, in the case where absorption occurs with probability less than 1. The results are illustrated by applications to the general birth and death process and the linear birth, death and catastrophe process.

  9. Reproducibility of The Random Incidence Absorption Coefficient Converted From the Sabine Absorption Coefficient

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho; Chang, Ji-ho

    2015-01-01

    Absorption coefficients measured in reverberation chambers, Sabine absorption coefficients, suffer from two major problems. Firstly, they sometimes exceed unity. Secondly, the reproducibility of the Sabine absorption coefficients is quite poor, meaning that the Sabine absorption coefficients vary...

  10. Absorption and Metabolism of Xanthophylls

    Directory of Open Access Journals (Sweden)

    Eiichi Kotake-Nara

    2011-06-01

    Full Text Available Dietary carotenoids, especially xanthophylls, have attracted significant attention because of their characteristic biological activities, including anti-allergic, anti-cancer, and anti-obese actions. Although no less than forty carotenoids are ingested under usual dietary habits, only six carotenoids and their metabolites have been found in human tissues, suggesting selectivity in the intestinal absorption of carotenoids. Recently, facilitated diffusion in addition to simple diffusion has been reported to mediate the intestinal absorption of carotenoids in mammals. The selective absorption of carotenoids may be caused by uptake to the intestinal epithelia by the facilitated diffusion and an unknown excretion to intestinal lumen. It is well known that β-carotene can be metabolized to vitamin A after intestinal absorption of carotenoids, but little is known about the metabolic transformation of non provitamin A xanthophylls. The enzymatic oxidation of the secondary hydroxyl group leading to keto-carotenoids would occur as a common pathway of xanthophyll metabolism in mammals. This paper reviews the absorption and metabolism of xanthophylls by introducing recent advances in this field.

  11. Enhanced absorption cycle computer model

    Science.gov (United States)

    Grossman, G.; Wilk, M.

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperature boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorption systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system's components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H2O triple-effect cycles, LiCl-H2O solar-powered open absorption cycles, and NH3-H2O single-effect and generator-absorber heat exchange cycles. An appendix contains the user's manual.

  12. Absorption Efficiency of Receiving Antennas

    DEFF Research Database (Denmark)

    Andersen, Jørgen Bach; Frandsen, Aksel

    2005-01-01

    A receiving antenna with a matched load will always scatter some power. This paper sets an upper and a lower bound on the absorption efficiency (absorbed power over sum of absorbed and scattered powers), which lies between 0 and 100% depending on the directivities of the antenna and scatter...... patterns. It can approach 100% as closely as desired, although in practice this may not be an attractive solution. An example with a small endfire array of dipoles shows an efficiency of 93%. Several examples of small conical horn antennas are also given, and they all have absorption efficiencies less than...

  13. Nonlinear absorption in discrete systems

    Energy Technology Data Exchange (ETDEWEB)

    Spire, A; Leon, J [Physique Mathematique et Theorique, CNRS-UMR5825, Universite Montpellier 2, 34095 Montpellier (France)

    2004-10-01

    In the context of nonlinear scattering, a continuous wave incident onto a nonlinear discrete molecular chain of coupled oscillators can be partially absorbed as a result of a three-wave resonant interaction that couples two HF-waves of frequencies close to the edge of the Brillouin zone. Hence both nonlinearity and discreteness are necessary for generating this new absorption process which manifests itself by soliton generation in the medium. As a paradigm of this nonlinear absorption we consider here the Davydov model that describes exciton-phonon coupling in hydrogen-bonded molecular chains.

  14. Absorption-heat-pump system

    Science.gov (United States)

    Grossman, G.; Perez-Blanco, H.

    1983-06-16

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

  15. Aerosol Absorption Measurements in MILAGRO.

    Science.gov (United States)

    Gaffney, J. S.; Marley, N. A.; Arnott, W. P.; Paredes-Miranda, L.; Barnard, J. C.

    2007-12-01

    During the month of March 2006, a number of instruments were used to determine the absorption characteristics of aerosols found in the Mexico City Megacity and nearby Valley of Mexico. These measurements were taken as part of the Department of Energy's Megacity Aerosol Experiment - Mexico City (MAX-Mex) that was carried out in collaboration with the Megacity Interactions: Local and Global Research Observations (MILAGRO) campaign. MILAGRO was a joint effort between the DOE, NSF, NASA, and Mexican agencies aimed at understanding the impacts of a megacity on the urban and regional scale. A super-site was operated at the Instituto Mexicano de Petroleo in Mexico City (designated T-0) and at the Universidad Technologica de Tecamac (designated T-1) that was located about 35 km to the north east of the T-0 site in the State of Mexico. A third site was located at a private rancho in the State of Hidalgo approximately another 35 km to the northeast (designated T-2). Aerosol absorption measurements were taken in real time using a number of instruments at the T-0 and T-1 sites. These included a seven wavelength aethalometer, a multi-angle absorption photometer (MAAP), and a photo-acoustic spectrometer. Aerosol absorption was also derived from spectral radiometers including a multi-filter rotating band spectral radiometer (MFRSR). The results clearly indicate that there is significant aerosol absorption by the aerosols in the Mexico City megacity region. The absorption can lead to single scattering albedo reduction leading to values below 0.5 under some circumstances. The absorption is also found to deviate from that expected for a "well-behaved" soot anticipated from diesel engine emissions, i.e. from a simple 1/lambda wavelength dependence for absorption. Indeed, enhanced absorption is seen in the region of 300-450 nm in many cases, particularly in the afternoon periods indicating that secondary organic aerosols are contributing to the aerosol absorption. This is likely due

  16. Low-Absorption Laser Windows

    Science.gov (United States)

    1976-04-01

    ABSORPTION MEASUREMENTS AT 1.06 Urn James W. Davisson U.S. Naval Research Laboratory Washington, D.C. 20375 ABSTRACT A procedure for the chemical poli...W. Davisson , Fourth Laser Window Materials Conf. p. 466). The alkaline earth fluorides and LiF were mechanically polished by rubbing: till dry

  17. Theory of graphene saturable absorption

    Science.gov (United States)

    Marini, A.; Cox, J. D.; García de Abajo, F. J.

    2017-03-01

    Saturable absorption is a nonperturbative nonlinear optical phenomenon that plays a pivotal role in the generation of ultrafast light pulses. Here we show that this effect emerges in graphene at unprecedentedly low light intensities, thus opening avenues to new nonlinear physics and applications in optical technology. Specifically, we theoretically investigate saturable absorption in extended graphene by developing a semianalytical nonperturbative single-particle approach, describing electron dynamics in the atomically-thin material using the two-dimensional Dirac equation for massless Dirac fermions, which is recast in the form of generalized Bloch equations. By solving the electron dynamics nonperturbatively, we account for both interband and intraband contributions to the intensity-dependent saturated conductivity and conclude that the former dominates regardless of the intrinsic doping state of the material. We obtain results in qualitative agreement with atomistic quantum-mechanical simulations of graphene nanoribbons including electron-electron interactions, finite-size, and higher-band effects. Remarkably, such effects are found to affect mainly the linear absorption, while the predicted saturation intensities are in good quantitative agreement in the limit of extended graphene. Additionally, we find that the modulation depth of saturable absorption in graphene can be electrically manipulated through an externally applied gate voltage. Our results are relevant for the development of graphene-based optoelectronic devices, as well as for applications in mode-locking and random lasers.

  18. Aerosol absorption and radiative forcing

    Directory of Open Access Journals (Sweden)

    P. Stier

    2007-10-01

    Full Text Available We present a comprehensive examination of aerosol absorption with a focus on evaluating the sensitivity of the global distribution of aerosol absorption to key uncertainties in the process representation. For this purpose we extended the comprehensive aerosol-climate model ECHAM5-HAM by effective medium approximations for the calculation of aerosol effective refractive indices, updated black carbon refractive indices, new cloud radiative properties considering the effect of aerosol inclusions, as well as by modules for the calculation of long-wave aerosol radiative properties and instantaneous aerosol forcing. The evaluation of the simulated aerosol absorption optical depth with the AERONET sun-photometer network shows a good agreement in the large scale global patterns. On a regional basis it becomes evident that the update of the BC refractive indices to Bond and Bergstrom (2006 significantly improves the previous underestimation of the aerosol absorption optical depth. In the global annual-mean, absorption acts to reduce the short-wave anthropogenic aerosol top-of-atmosphere (TOA radiative forcing clear-sky from −0.79 to −0.53 W m−2 (33% and all-sky from −0.47 to −0.13 W m−2 (72%. Our results confirm that basic assumptions about the BC refractive index play a key role for aerosol absorption and radiative forcing. The effect of the usage of more accurate effective medium approximations is comparably small. We demonstrate that the diversity in the AeroCom land-surface albedo fields contributes to the uncertainty in the simulated anthropogenic aerosol radiative forcings: the usage of an upper versus lower bound of the AeroCom land albedos introduces a global annual-mean TOA forcing range of 0.19 W m−2 (36% clear-sky and of 0.12 W m−2 (92% all-sky. The consideration of black carbon inclusions on cloud radiative properties results in a small global annual-mean all-sky absorption of 0.05 W

  19. Absorptive capacity and smart companies

    Directory of Open Access Journals (Sweden)

    Patricia Moro González

    2014-12-01

    Full Text Available Purpose: The current competitive environment is substantially modifying the organizations’ learning processes due to a global increase of available information allowing this to be transformed into knowledge. This opportunity has been exploited since the nineties by the tools of “Business Analytics” and “Business Intelligence” but, nevertheless, being integrated in the study of new organizational capacities engaged in the process of creating intelligence inside organizations is still an outstanding task. The review of the concept of absorptive capacity and a detailed study from the perspective of this new reality will be the main objective of study of this paper.Design/methodology/approach: By comparing classical absorptive capacity and absorptive capacity from the point of view of information management tools in each one of the three stages of the organizational learning cycle, some gaps of the former are overcome/fulfilled. The academic/bibliographical references provided in this paper have been obtained from ISI web of knowledge, Scopus and Dialnet data bases, supporting the state of affairs on absorptive capacity and thereafter filtering by "Business Intelligence" and "Business Analytics". Specialized websites and Business Schools` Publications there have also been included, crowning the content on information management tools used that are currently used in the strategic consulting.Findings: Our contribution to the literature is the development of "smart absorptive capacity". This is a new capacity emerging from the reformulation of the classical concept of absorptive capacity wherein some aspects of its definition that might have been omitted are emphasized. The result of this new approach is the creation of a new Theoretical Model of Organizational Intelligence, which aims to explain, within the framework of the Resources and Capabilities Theory, the competitive advantage achieved by the so-called smart companies

  20. Carotenoid absorption in chicken intestine.

    Science.gov (United States)

    Gómez, R; Alonso, A; Martín, M

    1978-09-01

    The powdered flowers of marigold (Tagetes erecta) are used as a cheap source of carotenoids in avicultura. Lutein (3,3'-dyhydroxi-alpha-carotene) constitutes up to 85 to 90% of marigold carotenoids. In the plant, lutein is found esterified to palmitic or estearic acid. In chicken, carotenoid is hydrolized in the first portion of the small intestine, and absorbed as free lutein. After the absorption, lutein is not re-esterified in the different chicken tissues.

  1. Geometrical interpretation of optical absorption

    Energy Technology Data Exchange (ETDEWEB)

    Monzon, J. J.; Barriuso, A. G.; Sanchez-Soto, L. L. [Departamento de Optica, Facultad de Fisica, Universidad Complutense, E-28040 Madrid (Spain); Montesinos-Amilibia, J. M. [Departamento de Geometria y Topologia, Facultad de Matematicas, Universidad Complutense, E-28040 Madrid (Spain)

    2011-08-15

    We reinterpret the transfer matrix for an absorbing system in very simple geometrical terms. In appropriate variables, the system appears as performing a Lorentz transformation in a (1 + 3)-dimensional space. Using homogeneous coordinates, we map that action on the unit sphere, which is at the realm of the Klein model of hyperbolic geometry. The effects of absorption appear then as a loxodromic transformation, that is, a rhumb line crossing all the meridians at the same angle.

  2. On the nature of absorption

    CERN Document Server

    Barger, V; Halzen, F

    1972-01-01

    The imaginary helicity non-flip omega exchange amplitudes in KN and NN scattering are determined versus t and s from data on elastic differential cross section differences. The omega -universality prediction Im omega /sub N/(t)= 3 Im omega /sub K/(t), is found to be satisfied for 0absorptive cuts as small t preserve universality. The impact parameter distributions of the omega amplitudes show: (i) a peripheral peak centred around b approximately=1 fm, with Delta b approximately =+or-0.5 fm in KN and Delta b approximately=+or-0.75 fm in NN; (ii) a sizeable negative contribution at small b, more negative in NN than in KN, (iii) a smaller tail of negative contributions around b approximately=2 fm. Strong absorption of the omega -pole imaginary amplitude with lambda values around two is needed to reproduced this structure. A new version of the absorption model suggested by pi N amplitude analysis, is confirmed by the results. (20 refs).

  3. Topical absorption and systemic toxicity.

    Science.gov (United States)

    Alikhan, Fatima Sasha; Maibach, Howard

    2011-09-01

    Dermal absorption of some chemicals and drugs can cause systemic toxicity. We evaluated several case reports from the past decade, which discuss the dermal absorption of a specific chemical and potential local and systemic effects. We focused on herbicide and pesticide exposure along with exposure to cutaneous medication, occupational contact, and cosmeceutical exposure. Although causality cannot be established in most cases, it is critical to be aware of the possible effects of topical absorption that may not be immediately apparent. We recommended further studies on specific chemicals to ascertain causality and determine the highest exposure level with no observed adverse affect level (NOAEL) and the reference dose (RfD). Post-marketing epidemiology data in most geographical areas are markedly limited. A weak link in public health resides in the inadequate reporting and workup of alleged chemically related adverse effects. This arena mandates a re-thinking of how to increase this reporting, and workup, as a backup to our preclinical and clinical studies. Public awareness and funding will be rewarded by increased evidence to backup pre-approval pre-marketing studies.

  4. Organizational forms and knowledge absorption

    Directory of Open Access Journals (Sweden)

    Radovanović Nikola

    2016-01-01

    Full Text Available Managing the entire portion of knowledge in an organization is a challenging task. At the organizational level, there can be enormous quantities of unknown, poorly valued or inefficiently applied knowledge. This is normally followed with the underdeveloped potential or inability of organizations to absorb knowledge from external sources. Facilitation of the efficient internal flow of knowledge within the established communication network may positively affect organizational capacity to absorb or identify, share and subsequently apply knowledge to commercial ends. Based on the evidences that the adoption of different organizational forms affects knowledge flows within an organization, this research analyzed the relationship between common organizational forms and absorptive capacity of organizations. In this paper, we test the hypothesis stating that the organizational structure affects knowledge absorption and exploitation in the organization. The methodology included quantitative and qualitative research method based on a questionnaire, while the data has been statistically analyzed and the hypothesis has been tested with the use of cross-tabulation and chi-square tests. The findings suggest that the type of organizational form affects knowledge absorption capacity and that having a less formalized and more flexible structure in an organization increases absorbing and exploiting opportunities of potentially valuable knowledge.

  5. Mechanistic Approaches to Predicting Oral Drug Absorption

    OpenAIRE

    Huang, Weili; Lee, Sau Lawrence; Yu, Lawrence X.

    2009-01-01

    Modeling and simulation of oral drug absorption have been widely used in drug discovery, development, and regulation. Predictive absorption models are used to determine the rate and extent of oral drug absorption, facilitate lead drug candidate selection, establish formulation development strategy, and support the development of regulatory policies. This review highlights the development of recent drug absorption models including dispersion and compartmental models. The compartmental models i...

  6. Emission and Absorption Entropy Generation in Semiconductors

    OpenAIRE

    Reck, Kasper; Varpula, Aapo; Prunnila, Mika; Hansen, Ole

    2013-01-01

    While emission and absorption entropy generation is well known in black bodies, it has not previously been studied in semiconductors, even though semiconductors are widely used for solar light absorption in modern solar cells [1]. We present an analysis of the entropy generation in semiconductor materials due to emission and absorption of electromagnetic radiation. It is shown that the emission and absorption entropy generation reduces the fundamental limit on the efficiency of any semiconduc...

  7. Phytases for Improved Iron Absorption

    DEFF Research Database (Denmark)

    Nielsen, Anne Veller Friis; Nyffenegger, Christian; Meyer, Anne S.

    2014-01-01

    Microbial phytases (EC 3.1.3.8) catalyse dephosphorylation of phytic acid, which is the primary storage compound for phosphorous in cereal kernels. The negatively charged phosphates in phytic acid chelate iron (Fe3+) and thus retards iron bioavailability in humans 1. Supplementation of microbial...... phytase can improve iron absorption from cereal-based diets 2. In order for phytase to catalyse iron release in vivo the phytase must be robust to low pH and proteolysis in the gastric ventricle. Our work has compared the robustness of five different microbial phytases, evaluating thermal stability...

  8. Carbon Dioxide Absorption Heat Pump

    Science.gov (United States)

    Jones, Jack A. (Inventor)

    2002-01-01

    A carbon dioxide absorption heat pump cycle is disclosed using a high pressure stage and a super-critical cooling stage to provide a non-toxic system. Using carbon dioxide gas as the working fluid in the system, the present invention desorbs the CO2 from an absorbent and cools the gas in the super-critical state to deliver heat thereby. The cooled CO2 gas is then expanded thereby providing cooling and is returned to an absorber for further cycling. Strategic use of heat exchangers can increase the efficiency and performance of the system.

  9. Iodine Absorption Cells Purity Testing

    Directory of Open Access Journals (Sweden)

    Jan Hrabina

    2017-01-01

    Full Text Available This article deals with the evaluation of the chemical purity of iodine-filled absorption cells and the optical frequency references used for the frequency locking of laser standards. We summarize the recent trends and progress in absorption cell technology and we focus on methods for iodine cell purity testing. We compare two independent experimental systems based on the laser-induced fluorescence method, showing an improvement of measurement uncertainty by introducing a compensation system reducing unwanted influences. We show the advantages of this technique, which is relatively simple and does not require extensive hardware equipment. As an alternative to the traditionally used methods we propose an approach of hyperfine transitions’ spectral linewidth measurement. The key characteristic of this method is demonstrated on a set of testing iodine cells. The relationship between laser-induced fluorescence and transition linewidth methods will be presented as well as a summary of the advantages and disadvantages of the proposed technique (in comparison with traditional measurement approaches.

  10. Circumgalactic Oxygen Absorption and Feedback

    Science.gov (United States)

    Mathews, William G.; Prochaska, J. Xavier

    2017-09-01

    O vi absorption in quasar spectra caused by intervening circumgalactic atmospheres suggests a downturn in the atmospheric column density in sightlines passing beyond about 100 kpc from central star-forming galaxies. This turnover supports the hypothesis that the oxygen originates in the central galaxies. When converted into oxygen space density using an Abel integral inversion, the O vi columns require ≳ {10}9 M ⊙ of oxygen concentrated near 100 kpc. Circumgalactic gas within this radius cools in less than 1 Gyr and radiates ˜ {10}42.2 erg s-1 overall. The feedback power necessary to maintain such oxygen-rich atmospheres for many Gyr cannot be easily supplied by galactic supernovae. However, massive central black holes in star-forming galaxies may generate sufficient accretion power and intermittent shock waves at r˜ 100 {kpc} to balance circumgalactic radiation losses in late-type {L}\\star galaxies. The relative absence of O vi absorption observed in early-type, passive {L}\\star galaxies may arise from enhanced AGN feedback from their more massive central black holes.

  11. Iron Absorption in Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Fanis Missirlis

    2013-05-01

    Full Text Available The way in which Drosophila melanogaster acquires iron from the diet remains poorly understood despite iron absorption being of vital significance for larval growth. To describe the process of organismal iron absorption, consideration needs to be given to cellular iron import, storage, export and how intestinal epithelial cells sense and respond to iron availability. Here we review studies on the Divalent Metal Transporter-1 homolog Malvolio (iron import, the recent discovery that Multicopper Oxidase-1 has ferroxidase activity (iron export and the role of ferritin in the process of iron acquisition (iron storage. We also describe what is known about iron regulation in insect cells. We then draw upon knowledge from mammalian iron homeostasis to identify candidate genes in flies. Questions arise from the lack of conservation in Drosophila for key mammalian players, such as ferroportin, hepcidin and all the components of the hemochromatosis-related pathway. Drosophila and other insects also lack erythropoiesis. Thus, systemic iron regulation is likely to be conveyed by different signaling pathways and tissue requirements. The significance of regulating intestinal iron uptake is inferred from reports linking Drosophila developmental, immune, heat-shock and behavioral responses to iron sequestration.

  12. Iron Absorption in Drosophila melanogaster

    Science.gov (United States)

    Mandilaras, Konstantinos; Pathmanathan, Tharse; Missirlis, Fanis

    2013-01-01

    The way in which Drosophila melanogaster acquires iron from the diet remains poorly understood despite iron absorption being of vital significance for larval growth. To describe the process of organismal iron absorption, consideration needs to be given to cellular iron import, storage, export and how intestinal epithelial cells sense and respond to iron availability. Here we review studies on the Divalent Metal Transporter-1 homolog Malvolio (iron import), the recent discovery that Multicopper Oxidase-1 has ferroxidase activity (iron export) and the role of ferritin in the process of iron acquisition (iron storage). We also describe what is known about iron regulation in insect cells. We then draw upon knowledge from mammalian iron homeostasis to identify candidate genes in flies. Questions arise from the lack of conservation in Drosophila for key mammalian players, such as ferroportin, hepcidin and all the components of the hemochromatosis-related pathway. Drosophila and other insects also lack erythropoiesis. Thus, systemic iron regulation is likely to be conveyed by different signaling pathways and tissue requirements. The significance of regulating intestinal iron uptake is inferred from reports linking Drosophila developmental, immune, heat-shock and behavioral responses to iron sequestration. PMID:23686013

  13. Sound absorption with green materials

    Science.gov (United States)

    Trematerra, Amelia; Lombardi, Ilaria

    2017-07-01

    Green materials are a valid alternative to traditional materials that are by-products of processing oil. At the end of their useful life, green materials can be disposed of without polluting the environment. They are now being used in the construction and automotive industries. While, studies are currently being carried out in the aviation sector on the use of green materials for non-structural components of airplanes. Green materials can be used to improve the acoustic comfort inside buildings as well as mitigate reverberation, echoes effects and reduce the transmission of noise between rooms. In this paper, the acoustic measurements of the properties of green materials are reported. The absorption coefficient of samples of the materials were measured in the frequency range from 200 Hz to 2,000 Hz with an impedance tube, with the flow resistance being measured.

  14. HI Absorption in Merger Remnants

    Science.gov (United States)

    Teng, Stacy H.; Veileux, Sylvain; Baker, Andrew J.

    2012-01-01

    It has been proposed that ultraluminous infrared galaxies (ULIRGs) pass through a luminous starburst phase, followed by a dust-enshrouded AGN phase, and finally evolve into optically bright "naked" quasars once they shed their gas/dust reservoirs through powerful wind events. We present the results of our recent 21- cm HI survey of 21 merger remnants with the Green Bank Telescope. These remnants were selected from the QUEST (Quasar/ULIRG Evolution Study) sample of ULIRGs and PG quasars; our targets are all bolometrically dominated by AGN and sample all phases of the proposed ULIRG -> IR-excess quasar -> optical quasar sequence. We explore whether there is an evolutionary connection between ULIRGs and quasars by looking for the occurrence of HI absorption tracing neutral gas outflows; our results will allow us to identify where along the sequence the majority of a merger's gas reservoir is expelled.

  15. Absorption boundary conditions for geomertical acoustics

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2012-01-01

    Defining accurate acoustical boundary conditions is of crucial importance for room acoustic simulations. In predicting sound fields using phased geometrical acoustics methods, the absorption coefficients or surface impedances of the boundary surfaces can be used, but no guideline has been developed...... solutions. Two rectangular rooms with uniform and non-uniform absorption distributions are tested. It is concluded that the impedance and random incidence absorption boundary conditions produce reasonable results with some exceptions at low frequencies for acoustically soft materials....

  16. Vitamin B12 absorption from eggs.

    Science.gov (United States)

    Doscherholmen, A; McMahon, J; Ripley, D

    1975-09-01

    The assimilation of 57Co B12 from in vivo labeled eggs was much inferior to that of a comparable amount of crystalline 57Co B12. Furthermore, the absorption varied with the form in which the eggs were served. Judged by the urinary excretion test and the plasma absorption of radioactivity the average absorption from boiled and fried eggs was more than twice that from scrambled whole eggs, but less than half that absorbed from crystalline 57Co B12.

  17. Worldwide survey of absorption fluids data

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Zawacki, T.S.

    1988-01-01

    The overall objective of this study is to develop improved data for the thermodynamic, transport and physical properties of absorption fluids. A specific objective of this phase of the study is to compile, catalog and coarse-screen the available worldwide data of known absorption fluid systems and publish it as a reference document to be distributed to manufacturers, researchers and others active in absorption heat pump activities. 3 refs., 3 figs., 1 tab.

  18. Differential Photoacoustic Particle Absorption Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We developed a highly sensitive and compact instrument to directly measure particulate matter (PM) optical absorption. This device is based on differential...

  19. Absorption bands in the spectrum of Io

    Science.gov (United States)

    Cruikshank, D. P.; Jones, T. J.; Pilcher, C. B.

    1978-01-01

    Near-infrared spectra of Io in the region from 2.8 to 4.2 microns are reported which show distinct absorption features, the most notable at 4.1 microns. Frozen volatiles or atmospheric gases cannot account for these absorptions, nor do they resemble those seen in common silicate rocks. Several candidate substances, most notably nitrate and carbonate salts, show absorption features in this spectral region; the deepest band in the spectrum may be a nitrate absorption. The satellite surface is shown to be anhydrous, as indicated by the absence of the 3-micron bound water band.

  20. Absorption of ozone by porous particles

    Energy Technology Data Exchange (ETDEWEB)

    Afanas' ev, V.P.; Dorofeev, S.B.; Sinitsyn, V.I.; Smirnov, B.M.

    1981-11-01

    The absorption of ozone by porous zeolite, silica gel, and activated carbon particles has been studied experimentally. It was shown that in addition to absorption, dissociation of ozone on the surface plays an important and sometimes decisive role. The results obtained were used to analyze the nature of ball lightning.

  1. Scalar absorption by charged rotating black holes

    Science.gov (United States)

    Leite, Luiz C. S.; Benone, Carolina L.; Crispino, Luís C. B.

    2017-08-01

    We compute numerically the absorption cross section of planar massless scalar waves impinging upon a Kerr-Newman black hole with different incidence angles. We investigate the influence of the black hole electric charge and angular momentum in the absorption spectrum, comparing our numerical computations with analytical results for the limits of high and low frequency.

  2. Iron absorption from intrinsically-labeled lentils

    Science.gov (United States)

    Low iron (Fe) absorption from important staple foods may contribute to Fe deficiency in developing countries. To date, there are few studies examining the Fe bioavailability of pulse crops as commonly prepared and consumed by humans. The objectives of this study were to characterize the Fe absorpt...

  3. High-Absorptance Radiative Heat Sink

    Science.gov (United States)

    Cafferty, T.

    1983-01-01

    Absorptance of black-painted open-cell aluminum honeycomb improved by cutting honeycomb at angle or bias rather than straight across. This ensures honeycomb cavities escapes. At each reflection radiation attenuated by absorption. Applications include space-background simulators, space radiators, solar absorbers, and passive coolers for terrestrial use.

  4. Ultrafast THz Saturable Absorption in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hoffmann, Matthias C.

    2011-01-01

    We demonstrate THz saturable absorption in n-doped semiconductors GaAs, GaP, and Ge in a nonlinear THz time-domain spectroscopy experiment. Saturable absorption is caused by sample conductivity modulation due to electron heating and satellite valley scattering in the field of a strong THz pulse....

  5. Absorption, bioavailability and metabolism of flavonoids

    NARCIS (Netherlands)

    Hollman, P.C.H.

    2004-01-01

    To unravel mechanisms of action of dietary flavonoids in their potential role in disease prevention, it is crucial to know the factors that determine their release from foods, their extent of absorption, and their fate in the organism. Research on absorption, metabolism, and bioavailability of

  6. Emission and Absorption Entropy Generation in Semiconductors

    DEFF Research Database (Denmark)

    Reck, Kasper; Varpula, Aapo; Prunnila, Mika

    2013-01-01

    materials due to emission and absorption of electromagnetic radiation. It is shown that the emission and absorption entropy generation reduces the fundamental limit on the efficiency of any semiconductor solar cell even further than the Landsberg limit. The results are derived from purely thermodynamical...

  7. Atmospheric Solar Heating in Minor Absorption Bands

    Science.gov (United States)

    Chou, Ming-Dah

    1998-01-01

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

  8. Low absorptance porcelain-on-aluminum coating

    Science.gov (United States)

    Leggett, H.

    1979-01-01

    Porcelain thermal-control coating for aluminum sheet and foil has solar absorptance of 0.22. Specially formulated coating absorptance is highly stable, changing only 0.03 after 1,000 hours of exposure to simulated sunlight and can be applied by standard commercial methods.

  9. A Low-Cost Quantitative Absorption Spectrophotometer

    Science.gov (United States)

    Albert, Daniel R.; Todt, Michael A.; Davis, H. Floyd

    2012-01-01

    In an effort to make absorption spectrophotometry available to high school chemistry and physics classes, we have designed an inexpensive visible light absorption spectrophotometer. The spectrophotometer was constructed using LEGO blocks, a light emitting diode, optical elements (including a lens), a slide-mounted diffraction grating, and a…

  10. Regularity of the interband light absorption coefficient

    Indian Academy of Sciences (India)

    Light absorption coefficient; density of states; random operators. 1. ... The operators H. ± ω may be unbounded. However, the finite volume operators H ,ω are symmetric finite-dimensional matrices when is a finite set, so their ...... [1] Atoyan M S, Kazaryan E M and Sarkisyan H A, Interband light absorption in parabolic.

  11. Flue gas treatment with membrane gas absorption

    NARCIS (Netherlands)

    Klaassen, R.; Feron, P.H.M.; Jansen, A.E.

    1998-01-01

    Membrane gas absorption is a new, efficient and flexible way to carry out gas-liquid contacting operations with hollow fibre membranes. Advantages of gas absorption membranes over conventional G-L contactors are: -High specific surface area and rapid mass transfer resulting in very compact and low

  12. Terahertz absorption spectrum of triacetone triperoxide (TATP)

    Science.gov (United States)

    Wilkinson, John; Konek, Christopher T.; Moran, Jesse S.; Witko, Ewelina M.; Korter, Timothy M.

    2009-08-01

    We report here, for the first time, the terahertz absorption spectrum of triacetone triperoxide (TATP). The experimental spectra are coupled with solid-state density functional theory, and preliminary assignments are provided to gain physical insight into the experimental spectrum. The calculated absorption coefficients are in excellent agreement with experiment.

  13. Enriching Absorptive Capacity Through Social Interaction

    DEFF Research Database (Denmark)

    Hotho, Jasper Jaap; Becker-Ritterspach, Florian; Saka-Helmhout, Ayse

    absorptive capacity as it enables employees to participate in the transformation of new knowledge to the local context. Second, the findings illustrate how organizational conditions at the subsidiary level can impact subsidiary absorptive capacity by enabling or constraining local interaction patterns......Absorptive capacity is frequently highlighted as a key determinant of knowledge transfer within MNEs. But how individual behaviour translates to absorptive capacity at the subsidiary level, and exactly how this is contingent on subsidiaries’ social context, remains under-addressed. This not only...... limits our understanding of the causal linkage between individual and organizational level absorptive capacity, it also hampers further research on potentially relevant managerial and organizational antecedents, and limits the implications we can draw for practitioners in the field seeking to increase...

  14. Enriching Absorptive Capacity through Social Interaction

    DEFF Research Database (Denmark)

    Hotho, Jasper J.; Saka-Helmhout, Ayse; Becker-Ritterspach, Florian

    2012-01-01

    for subsidiary absorptive capacity as it enables employees to participate in the transformation of new knowledge to the local context and the development of local applications. The findings also illustrate how organizational conditions at the subsidiary level can impact subsidiary absorptive capacity by enabling......Absorptive capacity is frequently highlighted as a key determinant of knowledge transfer within multinational enterprises. But how individual behaviour translates into absorptive capacity at the subsidiary level, and how this is contingent on subsidiaries' social context, remains under......-addressed. This not only limits our understanding of the relationship between individual- and organizational-level absorptive capacity, but also hampers further research on potentially relevant managerial and organizational antecedents, and limits the implications we can draw for practitioners who seek to increase...

  15. Novel absorption detection techniques for capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Xue, Yongjun [Iowa State Univ., Ames, IA (United States)

    1994-07-27

    Capillary electrophoresis (CE) has emerged as one of the most versatile separation methods. However, efficient separation is not sufficient unless coupled to adequate detection. The narrow inner diameter (I.D.) of the capillary column raises a big challenge to detection methods. For UV-vis absorption detection, the concentration sensitivity is only at the μM level. Most commercial CE instruments are equipped with incoherent UV-vis lamps. Low-brightness, instability and inefficient coupling of the light source with the capillary limit the further improvement of UV-vis absorption detection in CE. The goals of this research have been to show the utility of laser-based absorption detection. The approaches involve: on-column double-beam laser absorption detection and its application to the detection of small ions and proteins, and absorption detection with the bubble-shaped flow cell.

  16. [Protein absorption in children with giardiasis].

    Science.gov (United States)

    Vega-Franco, L; Alvarez, E L; Romo, G; Bernal, R M

    1982-01-01

    With the object of investigating if Giardiasis interferes in the intestinal absorption of proteins, a study was made testing the absorption of gelatin in eleven. The determination of alpha-aminonitrogen, before giving gelatin, and the increase shown two hours later, was the criterion used to measure the capacity of absorption. Once the estimated basal had been carried out each of the children received tinidazol for three days, after which the large amount of gelatin was given once again so as to estimate any changes in the absorption, one the parasite had been eliminated. The results demonstrate that the presence of giardia in the intestine significantly restricts the absorption of the gelatin. We offer as proof the results of these findings in the growth of children who harbour this parasite.

  17. Absorption-Line Studies of Seyfert Galaxies

    Science.gov (United States)

    Shull, J. Michael

    We propose to undertake a "reverberation analysis" of the variable absorption lines ill two Seyfert Galaxies (NGC 4051 and Mrk 279) to help understand the origin of intrinsic absorption lines in AGNs. Stich an analysis is a powerful tool for elucidating the radial distribution of absorbing gas in the broad-line region (BLR) and narrow-line region (NLR). Only two Seyferts have previously been studied with this technique: NGC 4151 (Bromage el al. 1985; Clavel et al. 1987) and NGC 3516 (Voit, Shull, and Begelman 1987). The absorption features have been interpreted as an outflow of ionized clouds from the nuclear region or from an accretion disk affected by UV/X-ray heating. Neither the source of the absorbing gas in these Seyferts nor the "gene" which distingishes them from other Seyferts is known. Until the 1984 onset of absorption in Mrk 279, broad self-absorbed. lines had been observed only in Seyferts of low intrinsic luminosity, such as NGC 4051. Mrk 279 is intrinsically much brighter, and therefore more quasar-like, than the other three absorptionline Seyfert I's in the CfA sample. Thus, it may show how the absorption phenomenon changes at higher luminosity and could bridge the gap between the low luminosity absorption-line Seyferts and the well-studied broad absorption-line (BAL) QSO's. In addition, Mrk 279's significant redshift will allow us to study, for the first time, the Ly-alpha line in an absorption-line Seyfert. With 3 US-1 shifts for each of these two underobserved Seyferts, we can double the number of objects in which absorption-line variability has been studied and investigate why the absorption-line strengths correlate or anti-correlate with the UV continuum.

  18. Monitoring Telluric Absorption with CAMAL

    Science.gov (United States)

    Baker, Ashley D.; Blake, Cullen H.; Sliski, David H.

    2017-08-01

    Ground-based astronomical observations may be limited by telluric water vapor absorption, which is highly variable in time and significantly complicates both spectroscopy and photometry in the near-infrared (NIR). To achieve the sensitivity required to detect Earth-sized exoplanets in the NIR, simultaneous monitoring of precipitable water vapor (PWV) becomes necessary to mitigate the impact of variable telluric lines on radial velocity measurements and transit light curves. To address this issue, we present the Camera for the Automatic Monitoring of Atmospheric Lines (CAMAL), a stand-alone, inexpensive six-inch aperture telescope dedicated to measuring PWV at the Fred Lawrence Whipple Observatory on Mount Hopkins. CAMAL utilizes three narrowband NIR filters to trace the amount of atmospheric water vapor affecting simultaneous observations with the MINiature Exoplanet Radial Velocity Array (MINERVA) and MINERVA-Red telescopes. Here, we present the current design of CAMAL, discuss our data analysis methods, and show results from 11 nights of PWV measurements taken with CAMAL. For seven nights of data we have independent PWV measurements extracted from high-resolution stellar spectra taken with the Tillinghast Reflector Echelle Spectrometer (TRES) also located on Mount Hopkins. We use the TRES spectra to calibrate the CAMAL absolute PWV scale. Comparisons between CAMAL and TRES PWV estimates show excellent agreement, matching to within 1 mm over a 10 mm range in PWV. Analysis of CAMAL’s photometric precision propagates to PWV measurements precise to better than 0.5 mm in dry (PWV < 4 mm) conditions. We also find that CAMAL-derived PWVs are highly correlated with those from a GPS-based water vapor monitor located approximately 90 km away at Kitt Peak National Observatory, with a root mean square PWV difference of 0.8 mm.

  19. Aerosol Angstrom Absorption Coefficient Comparisons during MILAGRO.

    Science.gov (United States)

    Marley, N. A.; Marchany-Rivera, A.; Kelley, K. L.; Mangu, A.; Gaffney, J. S.

    2007-12-01

    Measurements of aerosol absorption were obtained as part of the MAX-Mex component of the MILAGRO field campaign at site T0 (Instituto Mexicano de Petroleo in Mexico City) by using a 7-channel aethalometer (Thermo- Anderson) during the month of March, 2006. The absorption measurements obtained in the field at 370, 470, 520, 590, 660, 880, and 950 nm were used to determine the aerosol Angstrom absorption exponents by linear regression. Since, unlike other absorbing aerosol species (e.g. humic like substances, nitrated PAHs), black carbon absorption is relatively constant from the ultraviolet to the infrared with an Angstrom absorption exponent of -1 (1), a comparison of the Angstrom exponents can indicate the presence of aerosol components with an enhanced UV absorption over that expected from BC content alone. The Angstrom exponents determined from the aerosol absorption measurements obtained in the field varied from - 0.7 to - 1.3 during the study and was generally lower in the afternoon than the morning hours, indicating an increase in secondary aerosol formation and photochemically generated UV absorbing species in the afternoon. Twelve-hour integrated samples of fine atmospheric aerosols (Petroleo (IMP) and CENICA.

  20. The effect of volatility on percutaneous absorption.

    Science.gov (United States)

    Rouse, Nicole C; Maibach, Howard I

    2016-01-01

    Topically applied chemicals may volatilize, or evaporate, from skin leaving behind a chemical residue with new percutaneous absorptive capabilities. Understanding volatilization of topical medications, such as sunscreens, fragrances, insect repellants, cosmetics and other commonly applied topicals may have implications for their safety and efficacy. A systematic review of English language articles from 1979 to 2014 was performed using key search terms. Articles were evaluated to assess the relationship between volatility and percutaneous absorption. A total of 12 articles were selected and reviewed. Key findings were that absorption is enhanced when coupled with a volatile substance, occlusion prevents evaporation and increases absorption, high ventilation increases volatilization and reduces absorption, and pH of skin has an affect on a chemical's volatility. The articles also brought to light that different methods may have an affect on volatility: different body regions; in vivo vs. in vitro; human vs. Data suggest that volatility is crucial for determining safety and efficacy of cutaneous exposures and therapies. Few articles have been documented reporting evaporation in the context of percutaneous absorption, and of those published, great variability exists in methods. Further investigation of volatility is needed to properly evaluate its role in percutaneous absorption.

  1. Gas treating absorption theory and practice

    CERN Document Server

    Eimer, Dag

    2014-01-01

    Gas Treating: Absorption Theory and Practice provides an introduction to the treatment of natural gas, synthesis gas and flue gas, addressing why it is necessary and the challenges involved.  The book concentrates in particular on the absorption-desorption process and mass transfer coupled with chemical reaction. Following a general introduction to gas treatment, the chemistry of CO2, H2S and amine systems is described, and selected topics from physical chemistry with relevance to gas treating are presented. Thereafter the absorption process is discussed in detail, column hardware is explain

  2. Psychological absorption. Affect investment in marijuana intoxication.

    Science.gov (United States)

    Fabian, W D; Fishkin, S M

    1991-01-01

    Absorption (a trait capacity for total attentional involvement) was reported to increase during episodes of marijuana intoxication. Several subsets of the absorption scale items specifically characterized marijuana intoxication, and groups of users and nonusers showed differential affective involvement with these experiences. Additionally, within the drug-using group, a positive correlation between frequency of marijuana use and affective ratings of these experiences was found. The findings support the hypothesis that a specific type of alteration in consciousness that enhances capacity for total attentional involvement (absorption) characterizes marijuana intoxication, and that this enhancement may act as a reinforcer, possibly influencing future use.

  3. Coherent Absorption of N00N States.

    Science.gov (United States)

    Roger, Thomas; Restuccia, Sara; Lyons, Ashley; Giovannini, Daniel; Romero, Jacquiline; Jeffers, John; Padgett, Miles; Faccio, Daniele

    2016-07-08

    Recent results in deeply subwavelength thickness films demonstrate coherent control and logical gate operations with both classical and single-photon light sources. However, quantum processing and devices typically involve more than one photon and nontrivial input quantum states. Here we experimentally investigate two-photon N00N state coherent absorption in a multilayer graphene film. Depending on the N00N state input phase, it is possible to selectively choose between single- or two-photon absorption of the input state in the graphene film. These results demonstrate that coherent absorption in the quantum regime exhibits unique features, opening up applications in multiphoton spectroscopy and imaging.

  4. Connecting X-ray absorption and 21 cm neutral hydrogen absorption in obscured radio AGN

    Science.gov (United States)

    Moss, V. A.; Allison, J. R.; Sadler, E. M.; Urquhart, R.; Soria, R.; Callingham, J. R.; Curran, S. J.; Musaeva, A.; Mahony, E. K.; Glowacki, M.; Farrell, S. A.; Bannister, K. W.; Chippendale, A. P.; Edwards, P. G.; Harvey-Smith, L.; Heywood, I.; Hotan, A. W.; Indermuehle, B. T.; Lenc, E.; Marvil, J.; McConnell, D.; Reynolds, J. E.; Voronkov, M. A.; Wark, R. M.; Whiting, M. T.

    2017-11-01

    Many radio galaxies show the presence of dense and dusty gas near the active nucleus. This can be traced by both 21 cm H I absorption and soft X-ray absorption, offering new insight into the physical nature of the circumnuclear medium of these distant galaxies. To better understand this relationship, we investigate soft X-ray absorption as an indicator for the detection of associated H I absorption, as part of preparation for the First Large Absorption Survey in H I to be undertaken with the Australian Square Kilometre Array Pathfinder (ASKAP). We present the results of our pilot study using the Boolardy Engineering Test Array, a precursor to ASKAP, to search for new absorption detections in radio sources brighter than 1 Jy that also feature soft X-ray absorption. Based on this pilot survey, we detected H I absorption towards the radio source PKS 1657-298 at a redshift of z = 0.42. This source also features the highest X-ray absorption ratio of our pilot sample by a factor of 3, which is consistent with our general findings that X-ray absorption predicates the presence of dense neutral gas. By comparing the X-ray properties of active galactic nuclei with and without detection of H I absorption at radio wavelengths, we find that X-ray hardness ratio and H I absorption optical depth are correlated at a statistical significance of 4.71σ. We conclude by considering the impact of these findings on future radio and X-ray absorption studies.

  5. Gintonin absorption in intestinal model systems

    Directory of Open Access Journals (Sweden)

    Byung-Hwan Lee

    2018-01-01

    Conclusion: The present study shows that gintonin could be absorbed in the intestine through transcellular and paracellular diffusion, and active transport. In addition, the lipid component of gintonin might play a key role in its intestinal absorption.

  6. Multiphoton absorption in amyloid protein fibres

    Science.gov (United States)

    Hanczyc, Piotr; Samoc, Marek; Norden, Bengt

    2013-12-01

    Fibrillization of peptides leads to the formation of amyloid fibres, which, when in large aggregates, are responsible for diseases such as Alzheimer's and Parkinson's. Here, we show that amyloids have strong nonlinear optical absorption, which is not present in native non-fibrillized protein. Z-scan and pump-probe experiments indicate that insulin and lysozyme β-amyloids, as well as α-synuclein fibres, exhibit either two-photon, three-photon or higher multiphoton absorption processes, depending on the wavelength of light. We propose that the enhanced multiphoton absorption is due to a cooperative mechanism involving through-space dipolar coupling between excited states of aromatic amino acids densely packed in the fibrous structures. This finding will provide the opportunity to develop nonlinear optical techniques to detect and study amyloid structures and also suggests that new protein-based materials with sizable multiphoton absorption could be designed for specific applications in nanotechnology, photonics and optoelectronics.

  7. The Driving Forces of Subsidiary Absorptive Capacity

    DEFF Research Database (Denmark)

    Schleimer, Stephanie C.; Pedersen, Torben

    2013-01-01

    capacity in order to compete in its focal market. The dual embeddedness of MNC subsidiaries plays a key role in this investigation, as subsidiaries belong to the MNC network and are simultaneously embedded in their host country environment. We argue that subsidiary absorptive capacity is formed...... as a purposeful response to this dual embeddedness. An analysis of marketing strategy absorptions undertaken by 213 subsidiaries reveals that MNCs can assist their subsidiaries to compete in competitive and dynamic focal markets by forming specific organizational mechanisms that are conducive to the development......The study investigates how a multinational corporation (MNC) can promote the absorptive capacity of its subsidiaries. The focus is on what drives the MNC subsidiary's ability to absorb marketing strategies that are initiated by the MNC parent, as well as how the subsidiary enacts on this absorptive...

  8. Differential Photoacoustic Particle Absorption Monitor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop a highly sensitive and compact monitor to measure light absorption from particulate matters. The fundamental of the proposed device is based on...

  9. Absorption fluids data survey: 1989 update

    Energy Technology Data Exchange (ETDEWEB)

    Macriss, R.A.; Zawacki, T.S. (Institute of Gas Technology, Chicago, IL (USA))

    1989-01-01

    This is an update of a series of prior reports on absorption fluids and data, ORNL/Sub/84-47989/1, 2, 3. It covers additional data developed and published mainly during 1985--88, and cites 44 additional references. Seventy-four different worldwide publications containing data relating to properties of binary, ternary, and multicomponent absorption fluids were identified. Of these, 30 manuscripts include applications of absorption fluid properties data toward evaluation, assessment, or design of chillers or heat pumps but do not include actual fluid properties data. The remaining 44 publications date as far back as 1929, but over 50% of these documents were published between 1985 and 1988. The texts of the 44 manuscripts are in English, German, Japanese, Russian, or French. The absorption fluids discussed in the 44 documents are combinations of 9 different refrigerant'' compounds and 30 single, 7 binary, and 1 ternary absorbent'' compounds. 44 refs., 21 tabs.

  10. Extending Organizational Antecedents Of Absorptive Capacity

    DEFF Research Database (Denmark)

    Burcharth, Ana Luiza de Araújo; Lettl, Christopher; Ulhøi, John Parm

    2015-01-01

    on organizational characteristics that encourage experimentation. Specifically, we argue that characteristics such as slack resources, tolerance for failure, willingness to cannibalize and external openness are important organizational antecedents for knowledge absorption activities as they prevent inertia. Drawing...

  11. Ultraviolet absorption cross sections of hydrogen peroxide

    Science.gov (United States)

    Lin, C. L.; Rohatgi, N. K.; Demore, W. B.

    1978-01-01

    Absorption cross-sections of hydrogen peroxide vapor and of neutral aqueous solutions of hydrogen peroxide were measured in the wavelength range from 195 to 350 nm at 296 K. The spectrophotometric procedure is described, and the reported cross-sections are compared with values obtained by other researchers. Photodissociation coefficients of atmospheric H2O2 were calculated for direct absorption of unscattered solar radiation, and the vertical distributions of these coefficients are shown for various solar zenith angles.

  12. Water Absorption Behavior of Hemp Hurds Composites

    OpenAIRE

    Nadezda Stevulova; Julia Cigasova; Pavol Purcz; Ivana Schwarzova; Frantisek Kacik; Anton Geffert

    2015-01-01

    In this paper, water sorption behavior of 28 days hardened composites based on hemp hurds and inorganic binder was studied. Two kinds of absorption tests on dried cube specimens in deionized water bath at laboratory temperature were performed. Short-term (after one hour water immersion) and long-term (up to 180 days) water absorption tests were carried out to study their durability. Short-term water sorption behavior of original hemp hurds composites depends on mean particle length of hemp an...

  13. Systemic Absorption of Nanomaterials by Oral Exposure

    DEFF Research Database (Denmark)

    Binderup, Mona-Lise; Bredsdorff, Lea; Beltoft, Vibe Meister

    This report and accompanying database systematically evaluates the reliability and relevance of the existing scientific literature regarding systemic absorption of nanomaterials by oral exposure and makes specific recommendations for future testing approaches.......This report and accompanying database systematically evaluates the reliability and relevance of the existing scientific literature regarding systemic absorption of nanomaterials by oral exposure and makes specific recommendations for future testing approaches....

  14. Enhancement of Kerr nonlinearity completely without absorption

    Science.gov (United States)

    Liang, Hong; Niu, Yueping; Deng, Li; Gong, Shangqing

    2017-12-01

    We investigate the enhancement of the Kerr nonlinearity in a four-level tripod-type atomic system completely without absorption. We study the effect of the incoherent pumping on the nonlinear susceptibility of the probe field and show that compared with that without the incoherent pumping, the Kerr nonlinearity can be enhanced with completely suppressed absorption at two different probe frequencies. Thus, we can get a symmetrical enhanced Kerr nonlinearity. Particularly, all of our results are in the case of Doppler broadening.

  15. The Automation of Sound Absorption Coefficient Measurement

    OpenAIRE

    Hermawanto, Denny; Suwandi, Achmad

    2006-01-01

    By manual method, the sound absorption coefficient measurement should be done by utilizing many type of equipment such as: measuring amplifier, level recorder, band-pass filter, protactor, etc. However it caused inefficient and need longer time in processing measurement data, therefore the automation system of sound absorption coefficient has been realized. An acoustical real time analyzer type B&K 2144 has been used to record the decay of sound pressure level, thus the processing data is dri...

  16. Morphology of Southern Hemisphere Riometer Auroral Absorption

    Science.gov (United States)

    2006-06-01

    Departamento de Geofísica Universidad de Concepción, Concepción CHILE foppiano@udec.cl ABSTRACT A morphology of riometer auroral absorption is...PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Departamento de Geofísica Universidad de...UNCLASSIFIED/UNLIMITED UNCLASSIFIED/UNLIMITED MORPHOLOGY OF SOUTHERN HEMISPHERE RIOMETER AURORAL ABSORPTION Alberto J. Foppiano Departamento de

  17. Simulation of an absorption cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Egrican, N. (Istanbul Technical Univ. (TR). Dept. of Mechanical Engineering); Yigit, A. (Uludag Univ., Bursa (TR). Faculty of Engineering)

    1992-06-01

    We describe a finite difference solution for combined heat and mass transfer on vapor absorption into a laminar liquid film. Heat- and mass-transfer coefficients are determined by calculating temperature and concentration variations at the film. A modular computer program has been developed for absorption systems to simulate various cycle configurations. The influence of component temperatures and heat-exchanger effectiveness on cooling coefficients of performance and component heat-transfer rates has been investigated to define optimum operating conditions. (author).

  18. Variations in the spectral values of specific absorption of phytoplankton

    Digital Repository Service at National Institute of Oceanography (India)

    Sathyendranath, S.; Lazzara, L.; Prieur, L.

    Absorption spectra of laboratory cultures of eight species of phytoplankton were studied. These spectra, normalized per unit of chlorophyll a concentration (specific absorption) show variability in magnitude and spectral form. Specific absorption...

  19. Small intestinal absorption during endotoxemia in swine.

    Science.gov (United States)

    Kanno, S; Emil, S; Kosi, M; Monforte-Munoz, H; Atkinson, J

    1996-10-01

    We studied the effects of systemic endotoxemia on small intestinal absorption in an in vivo animal model. Seven adolescent Yorkshire swine underwent creation of 25 cm distal ileal Thiry-Vella fistulae. After 1 week recovery, the fistulae were perfused with a solution of glucose and electrolytes labeled with 14C-PEG, and net absorption of water, Na+, Cl-, and glucose was calculated. Animals were studied under three different conditions: (1) Basal fasting state, (2) immediately after intravenous injection of E. coli lipopolysaccharide (LPS; 250 micrograms/kg), and (3) 24 hours after LPS. Water, Na+, and Cl- absorption was significantly reduced 2 hours after LPS, but recovered to baseline values by the third hour after LPS. Twenty-four hours after LPS water, Na+, and Cl- absorption was significantly decreased below baseline values. Glucose absorption after LPS paralleled that of water and electrolytes, except that the transient early recovery was not observed. Histological studies of the ileum after LPS showed marked epithelial inflammation at 6 hours, villous atrophy at 24 hours, and signs of recovery at 7 days. Intestinal absorption of water, electrolytes, and glucose is adversely affected in the immediate and early periods after an endotoxemic episode, but the histological epithelial injury secondary to endotoxemia is reversible.

  20. Arachidonic acid intestinal absorption: mechanism of transport and influence of luminal factors of absorption in vitro.

    Science.gov (United States)

    Chow, S L; Hollander, D

    1978-11-01

    The mechanism and characteristics of intestinal absorption of arachidonic acid were studied in vitro using everted intestinal sacs of the rat. Arachidonic acid absorption was studied at concentrations of 5 micron to 8.36 mM. The plot of absorption rate vs. concentration fitted best to a rectangular hyperbola at low micron concentrations and to a straight linear relationship in the mM range of concentrations. Metabolic inhibitors and uncouplers did not change absorption in either range of concentrations. The absorption of arachidonic acid increased with thinning of the unstirred water-layer, decrease in the pH, or the substitution of sodium taurocholate by Pluronic F 68 OR Tween 80. Absorption decreased following the equimolar additions of oleic, linoleic, and linolenic acids. Absorption rate did not change when the taurocholate concentration was varied from 5-15 mM or following the additions of butyric or glutamic acids, leucine, lysine, or dextrose. It was concluded that arachidonic acid is absorbed by a concentration-dependent dual mechanism of transport which is not energy dependent. At the low micron range of concentrations, facilitated diffusion is predominant, while at mM concentrations, simple diffusion is the dominant mechanism of absorption. Changes in the intestinal fluid composition, flow rate, and pH can modify the rate of absorption of arachidonic acid.

  1. UV laser long-path absorption spectroscopy

    Science.gov (United States)

    Dorn, Hans-Peter; Brauers, Theo; Neuroth, Rudolf

    1994-01-01

    Long path Differential Optical Absorption Spectroscopy (DOAS) using a picosecond UV laser as a light source was developed in our institute. Tropospheric OH radicals are measured by their rotational absorption lines around 308 nm. The spectra are obtained using a high resolution spectrograph. The detection system has been improved over the formerly used optomechanical scanning device by application of a photodiode array which increased the observed spectral range by a factor of 6 and which utilizes the light much more effectively leading to a considerable reduction of the measurement time. This technique provides direct measurements of OH because the signal is given by the product of the absorption coefficient and the OH concentration along the light path according to Lambert-Beers law. No calibration is needed. Since the integrated absorption coefficient is well known the accuracy of the measurement essentially depends on the extent to which the OH absorption pattern can be detected in the spectra. No interference by self generated OH radicals in the detection lightpath has been observed. The large bandwidth (greater than 0.15 nm) and the high spectral resolution (1.5 pm) allows absolute determination of interferences by other trace gas absorptions. The measurement error is directly accessible from the absorption-signal to baseline-noise ratio in the spectra. The applicability of the method strongly depends on visibility. Elevated concentrations of aerosols lead to considerable attenuation of the laser light which reduces the S/N-ratio. In the moderately polluted air of Julich, where we performed a number of OH measurement spectra. In addition absorption features of unidentified species were frequently detected. A quantitative deconvolution even of the known species is not easy to achieve and can leave residual structures in the spectra. Thus interferences usually increase the noise and deteriorate the OH detection sensitivity. Using diode arrays for sensitive

  2. Identifying the perfect absorption of metamaterial absorbers

    Science.gov (United States)

    Duan, G.; Schalch, J.; Zhao, X.; Zhang, J.; Averitt, R. D.; Zhang, X.

    2018-01-01

    We present a detailed analysis of the conditions that result in unity absorption in metamaterial absorbers to guide the design and optimization of this important class of functional electromagnetic composites. Multilayer absorbers consisting of a metamaterial layer, dielectric spacer, and ground plane are specifically considered. Using interference theory, the dielectric spacer thickness and resonant frequency for unity absorption can be numerically determined from the functional dependence of the relative phase shift of the total reflection. Further, using transmission line theory in combination with interference theory we obtain analytical expressions for the unity absorption resonance frequency and corresponding spacer layer thickness in terms of the bare resonant frequency of the metamaterial layer and metallic and dielectric losses within the absorber structure. These simple expressions reveal a redshift of the unity absorption frequency with increasing loss that, in turn, necessitates an increase in the thickness of the dielectric spacer. The results of our analysis are experimentally confirmed by performing reflection-based terahertz time-domain spectroscopy on fabricated absorber structures covering a range of dielectric spacer thicknesses with careful control of the loss accomplished through water absorption in a semiporous polyimide dielectric spacer. Our findings can be widely applied to guide the design and optimization of the metamaterial absorbers and sensors.

  3. Tissue ultrasound absorption measurement with MRI calorimetry.

    Science.gov (United States)

    Wang, Y; Hunt, J W; Foster, F S; Plewes, D B

    1999-01-01

    The renewed interest in the use of high intensity focused ultrasound (US) for minimally invasive magnetic resonance imaging (MRI)-guided thermal therapy has stimulated a review of the interaction mechanisms of US with tissue. Although the study of tissue US properties has been conducted extensively, agreements on the measured values of tissue US absorption are poor. We propose a noninvasive approach to measure tissue US absorption based on a form of MRI calorimetry. US absorption is measured in a small tissue sample through a knowledge of the US intensity distribution incident on the tissue and an MRI measurement of total absorbed energy arising from US exposure. US absorption measurements were conducted at room temperature for ex-vivo bovine liver tissue at 1 MHz, which led to a measured US absorption coefficient of 0.058 Np/cm or 0.504 dB/cm. Because this approach is noninvasive, the experimental complications exhibited in earlier studies are not present. Furthermore, this approach can be applied over a range of frequencies, tissues, and temperatures, which will aid in understanding of biothermal effects of high intensity US to improve thermal therapy.

  4. Dynamics of water absorption through superabsorbent polymer

    Science.gov (United States)

    Chang, Sooyoung; Kim, Wonjung

    2017-11-01

    Superabsorbent polymers (SAPs) consist of hydrophilic cross-linked polymer networks that can absorb and retain a great amount of water relative to their own mass, so that they are widely used for disposable diapers and holding soil moisture in agriculture. SAPs are typically available in the form of submillimeter-sized particles, and the water absorption is driven by capillary flows between particles as well as diffusion that entail swelling. Although the control of water absorption of SAPs is important in engineering applications, but the dynamics of water absorption in SAP particles has not been fully understood. We examine the dynamics of the water absorption of sodium polyacrylate, one of the most common SAP. We experimentally measured the water absorption of sodium polyacrylate particles in one-dimensional confined channel. The water flows through the particles were analyzed by capillarity dominant at the early stage and by diffusion involving volume expansion critical at a later stage. The results provide a quantitative basis of the hydrodynamic analysis of the water flow through SAP particles from a macroscopic point of view, facilitating the prediction of water uptake of SAPs in hygienic and agricultural applications. This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korea government (MSIP) (No.2015R1A2A2A04006181).

  5. Absorption and metabolism of the absorption enhancer didecanoylphosphatidylcholine in rabbit nasal epithelium in vivo

    DEFF Research Database (Denmark)

    Vermehren, C.; Johansen, P.B.; Hansen, Harald S.

    1997-01-01

    The absorption enhancer, didecanoylphosphatidylcholine (DDPC), improves the nasal absorption of human growth hormone in rabbits. We elucidated the uptake and the metabolism of 1,2-di[1-C]decanoyl-L-3-phosphatidylcholine and 1,2-didecanoyl-L-3-phosphatidyl[N-methyl-H]choline in rabbit nasal mucosa...

  6. Selective gas absorption by ionic liquids

    DEFF Research Database (Denmark)

    Shunmugavel, Saravanamurugan; Kegnæs, Søren; Due-Hansen, Johannes

    2010-01-01

    Reversible absorption performance for the flue gas components CO 2, NO and SO2 has been tested for several different ionic liquids (ILs) at different temperatures and flue gas compositions. Furthermore, different porous, high surface area carriers have been applied as supports for the ionic liquids...... to obtain Supported Ionic Liquid-Phase (SILP) absorber materials. The use of solid SILP absorbers with selected ILs were found to significantly improve the absorption capacity and sorption dynamics at low flue gas concentration, thus making the applicability of ILs viable in technical, continuous flow...... processes for flue gas cleaning. The results show that CO 2, NO and SO2 can be reversible and selective absorbed using different ILs and that Supported Ionic Liquid-Phase (SILP) absorbers are promising materials for industrial flue gas cleaning. Absorption/desorption dynamics can be tuned by temperatures...

  7. Nanofibrous membrane-based absorption refrigeration system

    Energy Technology Data Exchange (ETDEWEB)

    Isfahani, RN; Sampath, K; Moghaddam, S

    2013-12-01

    This paper presents a study on the efficacy of highly porous nanofibrous membranes for application in membrane-based absorbers and desorbers. Permeability studies showed that membranes with a pore size greater than about one micron have a sufficient permeability for application in the absorber heat exchanger. Membranes with smaller pores were found to be adequate for the desorber heat exchanger. The membranes were implemented in experimental membrane-based absorber and desorber modules and successfully tested. Parametric studies were conducted on both absorber and desorber processes. Studies on the absorption process were focused on the effects of water vapor pressure, cooling water temperature, and the solution velocity on the absorption rate. Desorption studies were conducted on the effects of wall temperature, vapor and solution pressures, and the solution velocity on the desorption rate. Significantly higher absorption and desorption rates than in the falling film absorbers and desorbers were achieved. Published by Elsevier Ltd.

  8. EMPLOYMENT ABSORPTION IN MANUFACTURING INDUSTRY: YOGYAKARTA CASE

    Directory of Open Access Journals (Sweden)

    Aurora Indra Putri

    2011-09-01

    Full Text Available Unemployment has been a main problem in economic development, especially in developing countries. Unemployment stems from the inability of the economy to absorb the growing labor force. This paper investigates factors influencing absorbtion of labor in Yogyakarta manufacturing industries. Variables hypothesized to affect the absorbtion are wage, labor productivity, non-wage spending, and output of production. It collects data from Indonesia Centre Bureau of Statistics, and uses panel data regression, namely common effect approach, to estimate the model. Employing Eviews software package, it finds that wage, labor productivity, and output production significantly influence labor absorption. However, non-wage spending does not significantly influence the absorption.Keywords: Labor absorption, wage, labor productivity, non-wage spendingJEL classification numbers: J01, J23, J24

  9. Metamaterial with electromagnetic transparency under multiband absorptions

    Science.gov (United States)

    Zhang, Xu; Qi, Limei

    2017-02-01

    We propose a metal-dielectric-metal (MDM) metamaterial that has an electromagnetic (EM) transparency spectrum under multiband absorptions in the C and the X bands. The ground continuous metal film used in the conventional metamaterial absorber (MA) is replaced by a structured ground plane (SGP) in our design. The band-pass properties of the front patterned metal film and the SGP determine the EM transparency spectrum, while the magnetic and the electric resonances in the MDM structure contribute to the multiband absorptions. Due to the symmetric structure of the unit cell, the absorption bands and the EM transparency spectrum of the metamaterial have the property of polarization independency. Despite the normal incidence, the metamaterial can also be used for non-normal incidence.

  10. Absorption of Soluble Gases by Atmospheric Nanoaerosols

    CERN Document Server

    Elperin, Tov; Krasovitov, Boris; Lushnikov, Alexey

    2012-01-01

    We investigate mass transfer during absorption of atmospheric trace soluble gases by a single droplet whose size is comparable to the molecular mean free path in air at normal conditions. It is assumed that the trace reactant diffuses to the droplet surface and then reacts with the substances inside the droplet according to the first order rate law. Our analysis applies a flux-matching theory of transport processes in gases and assumes constant thermophysical properties of the gases and liquids. We derive an integral equation of Volterra type for the transient molecular flux density to a liquid droplet and solve it numerically. Numerical calculations are performed for absorption of sulfur dioxide (SO2), dinitrogen trioxide (N2O3) and chlorine (Cl2) by liquid nanoaerosols accompanied by chemical dissociation reaction. It is shown that during gas absorption by nanoaerosols the kinetic effects play significant role, and neglecting kinetic effects leads to significant overestimation of the soluble gas flux into a...

  11. Plasmon absorption modulator systems and methods

    Science.gov (United States)

    Kekatpure, Rohan Deodatta; Davids, Paul

    2014-07-15

    Plasmon absorption modulator systems and methods are disclosed. A plasmon absorption modulator system includes a semiconductor substrate, a plurality of quantum well layers stacked on a top surface of the semiconductor substrate, and a metal layer formed on a top surface of the stack of quantum well layers. A method for modulating plasmonic current includes enabling propagation of the plasmonic current along a metal layer, and applying a voltage across the stack of quantum well layers to cause absorption of a portion of energy of the plasmonic current by the stack of quantum well layers. A metamaterial switching system includes a semiconductor substrate, a plurality of quantum well layers stacked on a top surface of the semiconductor substrate, and at least one metamaterial structure formed on a top surface of the stack of quantum well layers.

  12. Anomalous water absorption in porous materials

    CERN Document Server

    Lockington, D A

    2003-01-01

    The absorption of fluid by unsaturated, rigid porous materials may be characterized by the sorptivity. This is a simple parameter to determine and is increasingly being used as a measure of a material's resistance to exposure to fluids (especially moisture and reactive solutes) in aggressive environments. The complete isothermal absorption process is described by a nonlinear diffusion equation, with the hydraulic diffusivity being a strongly nonlinear function of the degree of saturation of the material. This diffusivity can be estimated from the sorptivity test. In a typical test the cumulative absorption is proportional to the square root of time. However, a number of researchers have observed deviation from this behaviour when the infiltrating fluid is water and there is some potential for chemo-mechanical interaction with the material. In that case the current interpretation of the test and estimation of the hydraulic diffusivity is no longer appropriate. Kuentz and Lavallee (2001) discuss the anomalous b...

  13. Investigation of two-photon absorption induced excited state absorption in a fluorenyl-based chromophore.

    Science.gov (United States)

    Li, Changwei; Yang, Kun; Feng, Yan; Su, Xinyan; Yang, Junyi; Jin, Xiao; Shui, Min; Wang, Yuxiao; Zhang, Xueru; Song, Yinglin; Xu, Hongyao

    2009-12-03

    Two-photon absorption induced excited state absorption in the solution of a new fluorenyl-based chromophore is investigated by a time-resolved pump-probe technique using femtosecond pulses. With the help of an additional femtosecond open-aperture Z-scan technique, numerical simulations based on a three-energy level model are used to interpret the experimental results, and we determine the nonlinear optical parameters of this new chromophore uniquely. Large two-photon absorption cross section and excited state absorption cross section for singlet excited state are obtained, indicating a good candidate for optical limiting devices. Moreover, the influence of two-beam coupling induced energy transfer in neat N,N'-dimethylformamide solvent is also considered, although this effect is strongly restrained by the instantaneous two-photon absorption.

  14. Review on absorption technology with emphasis on small capacity absorption machines

    Directory of Open Access Journals (Sweden)

    Labus Jerko M.

    2013-01-01

    Full Text Available The aim of this paper is to review the past achievements in the field of absorption systems, their potential and possible directions for future development. Various types of absorption systems and research on working fluids are discussed in detail. Among various applications, solar cooling and combined cooling, heating and power (CCHP are identified as two most promising applications for further development of absorption machines. Under the same framework, special attention is given to the small capacity absorption machines and their current status at the market. Although this technology looks promising, it is still in development and many issues are open. With respect to that fact, this paper covers all the relevant aspects for further development of small capacity absorption machines.

  15. Equivalent sound absorption area in a rectangular reverberant room (Sabine's sound absorption factor)

    Science.gov (United States)

    Tohyama, M.

    1986-07-01

    The equivalent sound absorption area in a rectangular reverberant room can be derived from the initial first and second derivatives (initial decay rate of the time derivative) of the ensemble and space-averaged sound energy decay curve. At low frequency bands, how to estimate the equivalent sound absorption area from the reverberation time has not been theoretically interpreted. This is because the decay curve is not linear in logarithmic scales. The formula for the absorption area derived here, however, does not contain the reverberation time. It shows the theoretical relation between the absorption area and the initial slopes of the decay curve. The equivalent absorption area and averaged damping constants can be estimated theoretically according to the relation derived here for low frequency bands.

  16. Aerosol optical absorption measurements with photoacoustic spectroscopy

    Science.gov (United States)

    Liu, Kun; Wang, Lei; Liu, Qiang; Wang, Guishi; Tan, Tu; Zhang, Weijun; Chen, Weidong; Gao, Xiaoming

    2015-04-01

    Many parameters related to radiative forcing in climate research are known only with large uncertainties. And one of the largest uncertainties in global radiative forcing is the contribution from aerosols. Aerosols can scatter or absorb the electromagnetic radiation, thus may have negative or positive effects on the radiative forcing of the atmosphere, respectively [1]. And the magnitude of the effect is directly related to the quantity of light absorbed by aerosols [2,3]. Thus, sensitivity and precision measurement of aerosol optical absorption is crucial for climate research. Photoacoustic spectroscopy (PAS) is commonly recognized as one of the best candidates to measure the light absorption of aerosols [4]. A PAS based sensor for aerosol optical absorption measurement was developed. A 532 nm semiconductor laser with an effective power of 160 mW was used as a light source of the PAS sensor. The PAS sensor was calibrated by using known concentration NO2. The minimum detectable optical absorption coefficient (OAC) of aerosol was determined to be 1 Mm-1. 24 hours continues measurement of OAC of aerosol in the ambient air was carried out. And a novel three wavelength PAS aerosol OAC sensor is in development for analysis of aerosol wavelength-dependent absorption Angstrom coefficient. Reference [1] U. Lohmann and J. Feichter, Global indirect aerosol effects: a review, Atmos. Chem. Phys. 5, 715-737 (2005) [2] M. Z. Jacobson, Strong radiative heating due to the mixing state of black carbon in atmospheric aerosols, Nature 409, 695-697 (2001) [3] V. Ramanathan and G. Carmichae, Global and regional climate changes due to black carbon, nature geoscience 1, 221-227 (2008) [4] W.P Arnott, H. Moosmuller, C. F. Rogers, T. Jin, and R. Bruch, Photoacoustic spectrometer for measuring light absorption by aerosol: instrument description. Atmos. Environ. 33, 2845-2852 (1999).

  17. Enhanced absorption cycle computer model. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Grossman, G.; Wilk, M. [Technion-Israel Inst. of Tech., Haifa (Israel). Faculty of Mechanical Engineering

    1993-09-01

    Absorption heat pumps have received renewed and increasing attention in the past two decades. The rising cost of electricity has made the particular features of this heat-powered cycle attractive for both residential and industrial applications. Solar-powered absorption chillers, gas-fired domestic heat pumps, and waste-heat-powered industrial temperatures boosters are a few of the applications recently subjected to intensive research and development. The absorption heat pump research community has begun to search for both advanced cycles in various multistage configurations and new working fluid combinations with potential for enhanced performance and reliability. The development of working absorptions systems has created a need for reliable and effective system simulations. A computer code has been developed for simulation of absorption systems at steady state in a flexible and modular form, making it possible to investigate various cycle configurations with different working fluids. The code is based on unit subroutines containing the governing equations for the system`s components and property subroutines containing thermodynamic properties of the working fluids. The user conveys to the computer an image of his cycle by specifying the different subunits and their interconnections. Based on this information, the program calculates the temperature, flow rate, concentration, pressure, and vapor fraction at each state point in the system, and the heat duty at each unit, from which the coefficient of performance (COP) may be determined. This report describes the code and its operation, including improvements introduced into the present version. Simulation results are described for LiBr-H{sub 2}O triple-effect cycles, LiCl-H{sub 2}O solar-powered open absorption cycles, and NH{sub 3}-H{sub 2}O single-effect and generator-absorber heat exchange cycles. An appendix contains the User`s Manual.

  18. Rock physics investigation of seismic wave absorption in reservoir ...

    African Journals Online (AJOL)

    The difference between modulus estimated at high and low frequencies is translated to the coefficient of absorption (or inverse quality factor). Absorption estimated at ... interpret for fluid units. Information about seismic absorption can also be used, by means of absorption compensation, to enhance seismic data resolution.

  19. ABRASIVE ABSORPTION STUDY IN AWJ CUTTING

    Directory of Open Access Journals (Sweden)

    Bogdan BARABAŞ

    2016-11-01

    Full Text Available This paper studies the forming process of the hydro abrasive jet and the factors that determine its behaviour after leaving the nozzle until the moment of impact with the piece, in order to obtain an optimized configuration of the processing. The objectives are those of obtaining optimal surfaces in terms of quality, increased productivity and reduced costs. The paper specifies the model of the jet forming through air and abrasive absorption. The obtained results have confirmed the importance of exactly configuring the abrasive quantity in the jet through modifying the size of the abrasive grains and the attraction force required for their absorption.

  20. Porosity and liquid absorption of cement paste

    DEFF Research Database (Denmark)

    Krus, M.; Hansen, Kurt Kielsgaard; Kunzel, H. M.

    1997-01-01

    be a slowing-down effect which is related to water because the absorption of organic liquids, such as hexane, is quite normal. Measurements of the porosity of hardened cement paste determined by helium pycnometry and water saturation show that water molecules can enter spaces in the microstructure which...... are not accessible to the smaller helium atoms. Considering the results of dilatation tests both before and after water and hexane saturation, it seems possible that a contraction of capillary pores due to moisture-related swelling of the cement gel leads to the non-linear water absorption over the square root...

  1. Absorptive routines and international patent performance

    Directory of Open Access Journals (Sweden)

    Fernando E. García-Muiña

    2017-04-01

    We enrich the treatment of the absorptive capacity phases including the moderating effects between routines associated to the traditional potential-realized absorptive capacities. Taking into account external knowledge search strategies, the deeper external relationships, the better transference and appropriation of specific external knowledge. Nevertheless, when the moderating role of assimilation is included, cooperation agreements appear as the most efficient source of external knowledge. Finally, we show that technological tools let firms store and structure the information making easier its use for international patenting. This positive effect is reinforced in the presence of exploitation routines, since technological knowledge will better fit to the industry's key factors of success.

  2. Spectral line absorption measurement using optical cavities.

    Science.gov (United States)

    Blanaru, D. L.

    1973-01-01

    A simple technique using a conventional gas laser with spherical mirrors having identical radii of curvature in the nonoscillating regime for spectral line absorption measurements is described and applications for laser work are suggested. The theory of the measurement carried out in the geometrical optical approach for Doppler-broadened lines was checked experimentally and conditions are specified for which measurement inaccuracies of the order of 1% for the peak value of the line absorption coefficient can be obtained. Since the device provides a fine adjustment of the cavity losses, formation of the diffraction modes could be observed in the preoscillating regime of the optical cavity.

  3. Unveiling the Microfoundations of Absorptive Capacity

    DEFF Research Database (Denmark)

    Distel, Andreas Philipp

    2017-01-01

    explores the multilevel antecedents of absorptive capacity using survey data gathered from 342 informants at different levels of analysis in 106 medical technology firms. Multilevel structural equation modeling analyses indicate that formal and informal integration mechanisms are positively related......Although the concept of absorptive capacity has gained wide acceptance in the literature, our understanding of the origins of a firm’s ability to absorb and leverage new knowledge is limited. Drawing on Coleman’s (1990) bathtub framework for macro-micro-macro-relations in social science, this study...

  4. Achromatic THz absorption of conductive nanofilms

    Directory of Open Access Journals (Sweden)

    Qiang Yin

    2015-10-01

    Full Text Available According to the theory, an ultrathin conductive film can achromatically dissipate electromagnetic waves with frequency ranging from radio to terahertz. A moderate absorption effect, which gives rise to a maximal absorbance of 50%, can be found if an impedance matching condition is satisfied. We have experimentally demonstrated the frequency-irrelevant, maximal absorption by employing a conductive nanofilm and launching terahertz waves at Brewster angle when the sheet (square resistance of the film meets the impedance matching condition. In the entire terahertz spectral range covered by our experiments, the frequency-independent optical properties were consistent with the theoretical calculations.

  5. Water absorption characteristic of interlocking compressed earth brick units

    Science.gov (United States)

    Bakar, B. H. Abu; Saari, S.; Surip, N. A.

    2017-10-01

    This study aims to investigate the water absorption characteristic of interlocking compressed earth brick (ICEB) units. Apart from compressive strength, water absorption is an important property in masonry. This property can affect the quality of the brick itself and the bond strength between the brick and mortar in masonry structures and can result in reducing its strength properties. The units were tested for 24 h water absorption and 5 h boiling water absorption. A total of 170 ICEB units from four ICEB types underwent both tests. For the 24 h water absorption, the ICEB units were dried in the oven for 24 h and then cooled before being weighed. Thereafter, each brick was immersed in water for 24 h and weighed. The same specimens used for the 24 h water absorption test were re-used for the 5 h boiling water absorption test. After completing the 24 h water absorption test, the brick was boiled for 5-hours and weighed. The highest water absorption for the ICEBs in the 24-hour water absorption and 5 h boiling water absorption tests are 15.09% and 17.18%, respectively. The half brick has the highest water absorption (15.87%), whereas the beam brick has the lowest (13.20%). The water absorption of an ICEB unit is higher than that of normal bricks, although the water absorption of the former remains below the maximum rate of the brick water absorption (21%).

  6. Examination of the Measurement of Absorption Using the Reverberant Room Method for Highly Absorptive Acoustic Foam

    Science.gov (United States)

    Hughes, William O.; McNelis, Anne M.; Chris Nottoli; Eric Wolfram

    2015-01-01

    The absorption coefficient for material specimens are needed to quantify the expected acoustic performance of that material in its actual usage and environment. The ASTM C423-09a standard, "Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberant Room Method" is often used to measure the absorption coefficient of material test specimens. This method has its basics in the Sabine formula. Although widely used, the interpretation of these measurements are a topic of interest. For example, in certain cases the measured Sabine absorption coefficients are greater than 1.0 for highly absorptive materials. This is often attributed to the diffraction edge effect phenomenon. An investigative test program to measure the absorption properties of highly absorbent melamine foam has been performed at the Riverbank Acoustical Laboratories. This paper will present and discuss the test results relating to the effect of the test materials' surface area, thickness and edge sealing conditions. A follow-on paper is envisioned that will present and discuss the results relating to the spacing between multiple piece specimens, and the mounting condition of the test specimen.

  7. Realistic absorption coefficient of ultrathin films

    Science.gov (United States)

    Cesaria, M.; Caricato, A. P.; Martino, M.

    2012-10-01

    Both a theoretical algorithm and an experimental procedure are discussed of a new route to determine the absorption/scattering properties of thin films deposited on transparent substrates. Notably, the non-measurable contribution of the film-substrate interface is inherently accounted for. While the experimental procedure exploits only measurable spectra combined according to a very simple algorithm, the theoretical derivation does not require numerical handling of the acquired spectra or any assumption on the film homogeneity and substrate thickness. The film absorption response is estimated by subtracting the measured absorption spectrum of the bare substrate from that of the film on the substrate structure but in a non-straightforward way. In fact, an assumption about the absorption profile of the overall structure is introduced and a corrective factor accounting for the relative film-to-substrate thickness. The method is tested on films of a well known material (ITO) as a function of the film structural quality and influence of the film-substrate interface, both deliberately changed by thickness tuning and doping. Results are found fully consistent with information obtained by standard optical analysis and band gap values reported in the literature. Additionally, comparison with a conventional method demonstrates that our route is generally more accurate even if particularly suited for very thin films.

  8. Absorptive coating for aluminum solar panels

    Science.gov (United States)

    Desmet, D.; Jason, A.; Parr, A.

    1979-01-01

    Method for coating forming coating of copper oxide from copper component of sheet aluminum/copper alloy provides strong durable solar heat collector panels. Copper oxide coating has solar absorption characteristics similar to black chrome and is much simpler and less costly to produce.

  9. Oral Exposure and Absorption of Toxicants

    Science.gov (United States)

    This chapter provides an overview of the toxicokinetics of orally absorbed xenobiotics. This includes a description of the basic anatomy and physiology of the digestive tract most relevant to the absorption process. In addition, differences in anatomy and physiology between human...

  10. Simple parametrization of photon mass energy absorption ...

    Indian Academy of Sciences (India)

    Abstract. In this paper, we provide polynomial coefficients and a semi-empirical relation using which one can derive photon mass energy absorption coefficient of any H-, C-, N-,. O-based sample of biological interest containing any other elements in the atomic number range 2–40 and energy range 200–1500 keV.

  11. Experimental methodology for obtaining sound absorption coefficients

    Directory of Open Access Journals (Sweden)

    Carlos A. Macía M

    2011-07-01

    Full Text Available Objective: the authors propose a new methodology for estimating sound absorption coefficients using genetic algorithms. Methodology: sound waves are generated and conducted along a rectangular silencer. The waves are then attenuated by the absorbing material covering the silencer’s walls. The attenuated sound pressure level is used in a genetic algorithm-based search to find the parameters of the proposed attenuation expressions that include geometric factors, the wavelength and the absorption coefficient. Results: a variety of adjusted mathematical models were found that make it possible to estimate the absorption coefficients based on the characteristics of a rectangular silencer used for measuring the attenuation of the noise that passes through it. Conclusions: this methodology makes it possible to obtain the absorption coefficients of new materials in a cheap and simple manner. Although these coefficients might be slightly different from those obtained through other methodologies, they provide solutions within the engineering accuracy ranges that are used for designing noise control systems.

  12. The Absorption Refrigerator as a Thermal Transformer

    Science.gov (United States)

    Herrmann, F.

    2009-01-01

    The absorption refrigerator can be considered a thermal transformer, that is, a device that is analogous to the electric transformer. The analogy is based on the correspondence between the extensive quantities, entropy and electric charge and the intensive variables, temperature and electric potential. (Contains 1 footnote and 6 figures.)

  13. Resonant Light Absorption by Semiconductor Quantum Dots

    Directory of Open Access Journals (Sweden)

    I. G. Lang

    2009-01-01

    calculated in the case of a resonance with an exciton Γ6×Γ7 in cubical crystals of class. The interference of stimulating and induced electric and magnetic fields is taken into account. The cross-section of light absorption is proportional to the exciton nonradiative damping .

  14. Absorption heat pump cycles with NH

    NARCIS (Netherlands)

    Wang, M.; Infante Ferreira, C.A.

    2017-01-01

    Ionic liquids (ILs), as novel absorbents, draw considerable attention for their potential roles in replacing water or LiBr aqueous solutions in conventional NH3/H2O or H2O/LiBr absorption refrigeration or heat pump cycles. In this paper, performances of 9

  15. A method optimization study for atomic absorption ...

    African Journals Online (AJOL)

    A sensitive, reliable and relative fast method has been developed for the determination of total zinc in insulin by atomic absorption spectrophotometer. This designed study was used to optimize the procedures for the existing methods. Spectrograms of both standard and sample solutions of zinc were recorded by measuring ...

  16. Acetaminophen (paracetamol) oral absorption and clinical influences.

    Science.gov (United States)

    Raffa, Robert B; Pergolizzi, Joseph V; Taylor, Robert; Decker, John F; Patrick, Jeffrey T

    2014-09-01

    Acetaminophen (paracetamol) is a widely used nonopioid, non-NSAID analgesic that is effective against a variety of pain types, but the consequences of overdose can be severe. Because acetaminophen is so widely available as a single agent and is increasingly being formulated in fixed-ratio combination analgesic products for the potential additive or synergistic analgesic effect and/or reduced adverse effects, accidental cumulative overdose is an emergent concern. This has rekindled interest in the sites, processes, and pharmacokinetics of acetaminophen oral absorption and the clinical factors that can influence these. The absorption of oral acetaminophen occurs primarily along the small intestine by passive diffusion. Therefore, the rate-limiting step is the rate of gastric emptying into the intestines. Several clinical factors can affect absorption per se or the rate of gastric emptying, such as diet, concomitant medication, surgery, pregnancy, and others. Although acetaminophen does not have the abuse potential of opioids or the gastrointestinal bleeding or organ adverse effects of NSAIDs, excess amounts can produce serious hepatic injury. Thus, an understanding of the sites and features of acetaminophen absorption--and how they might be influenced by factors encountered in clinical practice--is important for pain management using this agent. It can also provide insight for design of formulations that would be less susceptible to clinical variables. © 2013 World Institute of Pain.

  17. Paracetamol absorption from Paramax, Panadol and Solpadeine.

    OpenAIRE

    Dougall, J R; Cunningham, B; Nimmo, W S

    1983-01-01

    Plasma paracetamol concentrations were measured after oral administration of three pharmaceutical preparations to four healthy volunteers. The formulations were Paramax (paracetamol with metoclopramide), Solpadeine (paracetamol with codeine and caffeine) and Panadol (paracetamol alone). After Solpadeine, concentrations at 15 min were significantly higher than after Panadol. Absorption of paracetamol from Paramax tablets did not differ significantly from Solpadeine or Panadol.

  18. Intestinal absorption of specific structured triacylglycerols

    DEFF Research Database (Denmark)

    Mu, Huiling; Høy, Carl-Erik

    2001-01-01

    To clarify the intestinal absorption pathway of medium-chain fatty acids from MMM-type structured triaclyglycerols containing both medium- and long-chain fatty acids, we studied the lymphatic transport of 1,3-dioctanoyl-2-linoleoyl-sn- glycerol (8:0/18:2/8:0), 1,3-didecanoyl-2-linoleoyl......-sn-glycerol (10:0/18:2/10:0), and 1,3-didodecanoyl-2-linoleoyl-sn-glycerol (12:0/18:2/12:0) in a rat model. Safflower oil was used in the absorption study in order to compare the absorption of medium- chain fatty acids and long-chain fatty acids, The triacylglycerol species of lymph Lipids were separated......-type triacylglycerols. From the present study we conclude that the medium-chain fatty acids from STAG, in addition to absorption into the portal blood as free fatty acids, are absorbed by the same pathway as the conventional long-chain triacylglycerols, that is, they are hydrolyzed into free fatty acids, absorbed...

  19. Theory of attosecond absorption spectroscopy in krypton

    DEFF Research Database (Denmark)

    Baggesen, Jan Conrad; Lindroth, Eva; Madsen, Lars Bojer

    2012-01-01

    A theory for time-domain attosecond pump–attosecond probe photoabsorption spectroscopy is formulated and related to the atomic response. The theory is illustrated through a study of attosecond absorption spectroscopy in krypton. The atomic parameters entering the formulation such as energies...

  20. Dermal absorption of chlorpyrifos in human volunteers

    NARCIS (Netherlands)

    Meuling, W.J.; Ravensberg, L.C.; Roza, L.; Hemmen, J.J. van

    2005-01-01

    Objective: The methods and results are described of a study on the dermal absorption of chlorpyrifos (CPF) in humans established via urinary excretion of the metabolite 3,5,6-trichloro-2-pyridinol (TCP). Methods: Two dermal, single, doses of CPF were applied in two study groups (A and B) each

  1. Plasmonic absorption properties of bimetallic metamaterials

    CERN Document Server

    Atmatzakis, Evangelos; Zheludev, Nikolay I

    2016-01-01

    We demonstrate polarization controlled absorption in plasmonic bimetallic metamaterials. We fabricate and experimentally characterize Au/Ni ring resonator arrays, where by varying the wavelength and polarization of the incident wave, local electromagnetic fields and dissipation can be suppressed or enhanced in the Au and Ni areas of the rings.

  2. Probing ultrafast carrier dynamics, nonlinear absorption and ...

    Indian Academy of Sciences (India)

    physics pp. 471–481. Probing ultrafast carrier dynamics, nonlinear absorption and refraction in core–shell silicon nanowires. SUNIL KUMAR1,∗, M KHORASANINEJAD2, M M ADACHI2,. K S KARIM2, S S SAINI2 and A K SOOD1. 1Department of Physics and Centre for Ultrafast Laser Applications, Indian Institute of Science,.

  3. Measuring sound absorption using local field assumptions

    NARCIS (Netherlands)

    Kuipers, E.R.

    2013-01-01

    To more effectively apply acoustically absorbing materials, it is desirable to measure angle-dependent sound absorption coefficients, preferably in situ. Existing measurement methods are based on an overall model of the acoustic field in front of the absorber, and are therefore sensitive to

  4. Dermal absorption and toxicological risk assessment

    NARCIS (Netherlands)

    Buist, H.

    2016-01-01

    Absorption of toxic substances via the skin is an important phenomenon in the assessment of the risk of exposure to these substances. People are exposed to a variety of substances and products via the skin, either directly or indirectly, while at work, at home or in public space. Pesticides, organic

  5. Coupled dual loop absorption heat pump

    Science.gov (United States)

    Sarkisian, Paul H.; Reimann, Robert C.; Biermann, Wendell J.

    1985-01-01

    A coupled dual loop absorption system which utilizes two separate complete loops. Each individual loop operates at three temperatures and two pressures. This low temperature loop absorber and condenser are thermally coupled to the high temperature loop evaporator, and the high temperature loop condenser and absorber are thermally coupled to the low temperature generator.

  6. Evaluation of atomic absorption Spectrophotometry (ashing, non ...

    African Journals Online (AJOL)

    Three commonly used techniques, namely atomic absorption spectrophotometry (AAS-Ashing and AAS-Non Ashing) and titrimetry (potassium permanganate titration) have been evaluated in this study to determine the calcium content in six food samples whose calcium levels ranged from 0 to more than 250mg/100g ...

  7. Analogue of electromagnetically induced absorption with double absorption windows in a plasmonic system.

    Directory of Open Access Journals (Sweden)

    Nianfa Zhong

    Full Text Available We report the observation of an analog of double electromagnetically induced absorption (EIA in a plasmonic system consisting of two disk resonators side-coupled to a discrete metal-insulator-metal (MIM waveguide. The finite-difference time-domain (FDTD simulation calculations show that two absorption windows are obtained and can be easily tuned by adjusting the parameters of the two resonance cavities. The consistence between the coupled-model theory and FDTD simulation results verify the feasibility of the proposed system. Since the scheme is easy to be fabricated, our proposed configuration may thus be applied to narrow-band filtering, absorptive switching, and absorber applications.

  8. Quantum Entanglement Molecular Absorption Spectrum Simulator

    Science.gov (United States)

    Nguyen, Quang-Viet; Kojima, Jun

    2006-01-01

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

  9. Absorption enhancement and total absorption in a graphene-waveguide hybrid structure

    Directory of Open Access Journals (Sweden)

    Jun Guo

    2017-02-01

    Full Text Available We propose a graphene/planar waveguide hybrid structure, and demonstrate total absorption in the visible wavelength range by means of attenuated total reflectance. The excitation of planar waveguide mode, which has strong near field enhancement and increased light interaction length with graphene, plays a vital role in total absorption. We analyze the origin and physical insight of total absorption theoretically by using an approximated reflectance, and show how to design such hybrid structure numerically. Utilizing the tunability of doped graphene, we discuss the possible application in optical modulators. We also achieve broadband absorption enhancement in near-IR range by cascading multiple graphene-waveguide hybrid structures. We believe our results will be useful not only for potential applications in optical devices, but also for studying other two-dimension materials.

  10. Terahertz absorption of dilute aqueous solutions.

    Science.gov (United States)

    Heyden, Matthias; Tobias, Douglas J; Matyushov, Dmitry V

    2012-12-21

    Absorption of terahertz (THz) radiation by aqueous solutions of large solutes reports on the polarization response of their hydration shells. This is because the dipolar relaxation of the solute is dynamically frozen at these frequencies, and most of the solute-induced absorption changes, apart from the expulsion of water, are caused by interfacial water. We propose a model expressing the dipolar response of solutions in terms of a single parameter, the interface dipole moment induced in the interfacial water by electromagnetic radiation. We apply this concept to experimental THz absorption of hydrated sugars, amino acids, and proteins. None of the solutes studied here follow the expectations of dielectric theories, which predict a negative projection of the interface dipole on the external electric field. We find that this prediction is not able to describe the available experimental data, which instead suggests a nearly zero interface dipole for sugars and a more diverse pattern for amino acids. Hydrophobic amino acids, similarly to sugars, give rise to near zero interface dipoles, while strongly hydrophilic ones are best described by a positive projection of the interface dipole on the external field. The sign of the interface dipole is connected to the slope of the absorption coefficient with the solute concentration. A positive slope, implying an increase in the solution polarity relative to water, mirrors results frequently reported for protein solutions. We therefore use molecular dynamics simulations of hydrated glucose and lambda repressor protein to calculate the interface dipole moments of these solutes and the concentration dependence of the THz absorption. The absorption at THz frequencies increases with increasing solute concentration in both cases, implying a higher polarity of the solution compared to bulk water. The structure of the hydration layer, extracted from simulations, is qualitatively similar in both cases, with spatial correlations

  11. MODIFICATION OF SILICON ABSORPTIVITY UNDER FEMTOSECOND LASER PULSE

    Directory of Open Access Journals (Sweden)

    I. V. Guk,

    2013-05-01

    Full Text Available The article deals with theoreticalmodeling results of the combined influence of nonlinear absorptivity and absorption coefficient on the spatial and temporal distribution of the electron-hole plasma and the dynamics of the specific absorption flux in silicon under femtosecond laser pulse. It is shown thatincreased absorption of the hot electron gas makes the main contribution to the change in specific absorption flux. Obtained results were compared with the known views about the polariton mechanism,which is usedfor the interpretation of femtosecond laser silicon microstructuring. There aredemonstratedThe need to consider absorption capacity dynamics in the regimes assessment of ultra short laser semiconductor processing.

  12. Exciton absorption in narrow armchair graphene nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Monozon, B.S. [Physics Department, Marine Technical University, 3 Lotsmanskaya Str., 190008 St. Petersburg (Russian Federation); Schmelcher, P., E-mail: pschmelc@physnet.uni-hamburg.de [Zentrum für Optische Quantentechnologien, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany); The Hamburg Centre for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg (Germany)

    2016-11-01

    We develop an analytical approach to the exciton optical absorption for narrow gap armchair graphene nanoribbons (AGNR). We focus on the regime of dominant size quantization in combination with the attractive electron–hole interaction. An adiabatic separation of slow and fast motions leads via the two-body Dirac equation to the isolated and coupled subband approximations. Discrete and continuous exciton states are in general coupled and form quasi-Rydberg series of purely discrete and resonance type character. The corresponding oscillator strengths and widths are derived. We show that the exciton peaks are blue-shifted, become broader and increase in magnitude upon narrowing the ribbon. At the edge of a subband the singularity related to the 1D density of states is transformed into finite absorption via the presence of the exciton. Our analytical results are in good agreement with those obtained by other methods including numerical approaches. Estimates of the expected experimental values are provided for realistic AGNR.

  13. Salicylate absorption from a bismuth subsalicylate preparation.

    Science.gov (United States)

    Feldman, S; Chen, S L; Pickering, L K; Cleary, T G; Ericsson, C D; Hulse, M

    1981-06-01

    The active ingredient in Pepto-Bismol (PB) (Norwich-Eaton), a common antidiarrheal, is bismuth subsalicylate. The absorption of salicylate after oral PB was studied in six fasted men. Plasma concentrations of total salicylate and the urinary excretion profile of salicylate were determined as a function of time and dose. After 60 ml PB, 500.1 +/- 33.6 mg (mean +/- SD) salicylate were recovered in urine, representing 95.0 +/- 6.4% of salicylic acid equivalents in 60 ml of the formulation. Peak plasma salicylate levels were reached 0.5 to 3 hr after ingestion and averaged 40.1 +/- 17.3 micrograms/ml. Absorption of salicylate was also essentially complete after 15- and 30-ml doses of the antidiarrheal preparation, and a linear relationship between dose and recovery of salicylate in the urine was found. Salicylate kinetics was nonlinear after a multiple-dose regimen of 60 ml every 6 hr for five doses.

  14. Medication absorption for patients with an ileostomy.

    Science.gov (United States)

    Moore, Susan

    The Association of Stoma Care Nurses UK (2013) has stressed that it is the role of the stoma care nurse to provide education to patients, carers, prescribers and other nurses. This includes the area of medication management. Ensuring patients with an ileostomy receive their medication in a form they can absorb is of importance to every stoma care nurse. Prescribing for patients with a stoma calls for special care. Each patient with an ileostomy requires assessment of their medication regimen for the purpose of identifying potential medical absorption issues. However, from an extensive literature search, it is evident that there is very little literature published on this subject. This article looks at the considerations to take into account when prescribing medication for ileostomy patients, and examines the results of a clinical audit on medication prescribers' knowledge of the impact of ileostomy formation on the absorption of medication.

  15. Skin absorption through atopic dermatitis skin

    DEFF Research Database (Denmark)

    Halling-Overgaard, A-S; Kezic, S; Jakasa, I

    2017-01-01

    Patients with atopic dermatitis have skin barrier impairment in both lesional and non-lesional skin. They are typically exposed to emollients daily and topical anti-inflammatory medicaments intermittently, hereby increasing the risk of developing contact allergy and systemic exposed to chemicals...... ingredients found in these topical preparations. We systematically searched for studies that investigated skin absorption of various penetrants, including medicaments, in atopic dermatitis patients, but also animals with experimentally induced dermatitis. We identified 40 articles, i.e. 11 human studies...... examining model penetrants, 26 human studies examining atopic dermatitis drugs and 3 animal studies. We conclude that atopic dermatitis patients have nearly two-fold increased skin absorption when compared to healthy controls. There is a need for well-designed epidemiological and dermato...

  16. AGN warm absorption with the ATHENA

    Science.gov (United States)

    Różańska, Agata; Gronkiewicz, Dominik; Hryniewicz, Krzysztof; Adhikari, Tek Prasad; Rataj, Mirosław; Skup, Konrad

    2016-06-01

    X-ray astronomy requires satellites to make progress in searching the distribution of hot matter in the Universe. Approximately 15 years period of time is needed for full construction of the flight instrument from the mission concept up to the launch. A new generation X-ray telescope ATHENA (the Advanced Telescope for High Energy Astrophysics) was approved by European Space Agency as a large mission with a launch foreseen in 2028. In this paper we show how microcalorimeter on the board of ATHENA will help us to study warm absorption observed in active galactic nuclei (AGN). We show that future observations will allow us to identify hundreds of lines from highly ionized elements and to measure Galactic warm absorption with very high precision.

  17. Absorption and photoluminescence in organic cavity QED

    Science.gov (United States)

    Herrera, Felipe; Spano, Frank C.

    2017-05-01

    Organic microcavities can be engineered to reach exotic quantum regimes of strong and ultrastrong light-matter coupling. However, the microscopic interpretation of their spectroscopic signals can be challenging due to the competition between coherent and dissipative processes involving electrons, vibrations, and cavity photons. We develop here a theoretical framework based on the Holstein-Tavis-Cummings model and a Markovian treatment of dissipation to account for previously unexplained spectroscopic features of organic microcavities consistently. We identify conditions for the formation of dark vibronic polaritons, a class of light-matter excitations that are not visible in absorption but lead to strong photoluminescence lines. We show that photon leakage from dark vibronic polaritons can be responsible for enhancing photoluminescence at the lower polariton frequency, and also can explain the apparent breakdown of reciprocity between absorption and emission in the vicinity of the bare molecular transition frequency. Successful comparison with experimental data demonstrates the applicability of our theory.

  18. Optical absorption spectra of Ag-11 isomers

    DEFF Research Database (Denmark)

    Martinez, Jose Ignacio; Fernandez, E. M.

    2009-01-01

    The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground-stale confi......The optical absorption spectra of the three most; stable structural isomers of the Ag-11 cluster were calculated using the time-dependent, density functional theory within the Casida formalism. The slightly different, spectra, of the isomers may permit the identification of the ground......-stale configuration predominantly present in the laboratory beams based on a direct comparison between the calculated photoabsorptiou response for the Ag-11 isomers and the measured spectra of medium-size silver clusters trapped in noble gas Ar and Ne matrices at different, temperatures. This assignment is confirmed...

  19. S-wave pion absorption by nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hachenberg, F.; Huefner, J.; Pirner, H.J.

    1976-01-01

    The absorption of pions by nuclei leads to an imaginary part in the optical potential for pionic atoms. The imaginary part is calculated by assuming the rescattering mechanism to dominate. The pion scatters off-shell by one nucleon and is absorbed by a second one. The ..pi..N scattering amplitude is constructed from a field theoretical model. Its off-mass shell properties prove important to reproduce the data.

  20. Improving the system of absorption unit refrigeration

    Directory of Open Access Journals (Sweden)

    Pokhol'chenko V. A.

    2016-12-01

    Full Text Available The problems of improving the absorption stove cooling system for high quality liquid smoke producing have been discussed in the paper. There is absorption stove construction presented which includes absorber, heat exchanger, low-temperature chamber, ultrasound radiator, and water spray generator. The data on the color depending of the experimental liquid smoke on main factors influencing the process – the coolant temperature and amount of fuel burned – have been presented. The specific surface of the fuel mass fraction of water in the fuel has been determined according to standard procedures. Transparency, color and intensity of staining smoke fluid have been determined organoleptically. The liquid smoke according to the requirements of the current normative documents on safety performance indicators has been tested by standard methods: determination of benzo(apyrene, phenol compounds and heavy metals. The equation for estimation the complex quality criterion of experimental liquid smoke on the basis of its chemical composition has been presented. The main factors influencing the complex quality criteria of experimental liquid smoke have been given there. They include the sound pressure level, amount of wood raw material required for pyrolysis, heat exchanging surface, refrigerant temperature, and ultrasound water spray generator efficiency. After processing the experimental data the regression equation of producing liquid smoke by absorption has been received. With the help of the mathematical modeling for absorption process of smoke components by fine-dispersed spray the rational parameters of liquid smoke processing have been founded. The project of technological instructions for the liquid smoke production by using the wood smoke and acoustically generated aerosol has been designed. The project of technical requirement "Liquid smoke Antonio Silver" has been designed as well; it has been tested at producing the commercial batch of dried

  1. Macromolecular absorption and cows' milk allergy.

    OpenAIRE

    Juvonen, P; Jakobsson, I; Lindberg, T.

    1991-01-01

    The absorption of macromolecules was analysed by measuring serum concentrations of human alpha-lactalbumin after feeding human milk, using a competitive radioimmunoassay. The control group consisted of 78 children fed by cows' milk formula; concentrations of alpha-lactalbumin in their serum were low. The median concentrations in the different age groups varied between 7-13 micrograms alpha-lactalbumin/1 serum/1 human milk/kg body weight. Twenty-eight children with cows' milk allergy were stud...

  2. Physicochemical patterns of ozone absorption by wood

    Science.gov (United States)

    Mamleeva, N. A.; Lunin, V. V.

    2016-11-01

    Results from studying aspen and pine wood ozonation are presented. The effect the concentration of ozone, the reagent residence time, and the content of water in a sample of wood has on ozone consumption rate and ozone demand are analyzed. The residence time is shown to determine the degree of ozone conversion degree and the depth of substrate destruction. The main patterns of ozone absorption by wood with different moisture content are found. Ways of optimizing the ozonation of plant biomass are outlined.

  3. Electromagnetic-radiation absorption by water

    Science.gov (United States)

    Lunkenheimer, P.; Emmert, S.; Gulich, R.; Köhler, M.; Wolf, M.; Schwab, M.; Loidl, A.

    2017-12-01

    Why does a microwave oven work? How does biological tissue absorb electromagnetic radiation? Astonishingly, we do not have a definite answer to these simple questions because the microscopic processes governing the absorption of electromagnetic waves by water are largely unclarified. This absorption can be quantified by dielectric loss spectra, which reveal a huge peak at a frequency of the exciting electric field of about 20 GHz and a gradual tailing off toward higher frequencies. The microscopic interpretation of such spectra is highly controversial and various superpositions of relaxation and resonance processes ascribed to single-molecule or molecule-cluster motions have been proposed for their analysis. By combining dielectric, microwave, THz, and far-infrared spectroscopy, here we provide nearly continuous temperature-dependent broadband spectra of water. Moreover, we find that corresponding spectra for aqueous solutions reveal the same features as pure water. However, in contrast to the latter, crystallization in these solutions can be avoided by supercooling. As different spectral contributions tend to disentangle at low temperatures, this enables us to deconvolute them when approaching the glass transition under cooling. We find that the overall spectral development, including the 20 GHz feature (employed for microwave heating), closely resembles the behavior known for common supercooled liquids. Thus water's absorption of electromagnetic waves at room temperature is not unusual but very similar to that of glass-forming liquids at elevated temperatures, deep in the low-viscosity liquid regime, and should be interpreted along similar lines.

  4. Falling Liquid Films in Absorption Machines

    Science.gov (United States)

    Fujita, Toshihiko

    The absorption machines of the lithium bromide-water type have recently been established as heat source equipments for residential and industrial use, which include refrigerating machines, heat pumps, and heat transformers. Several advanced cycle machines have also been proposed and tested. All of the absorption machines consist fundamentally of four kinds of heat exchangers, i.e. evaporator, absorber, generator, and condenser. The horizontal or vertical falling film system is usually applied to these heat exchangers, since the pressure drop which causes an undesirable change in the fluid temperature is relatively small in either system. The horizontal system is popular for the present, while the vertical system is going to be developed promisingly. This may save an installation space and also fit a plan for the Lorentz cycle. The purpose of this paper is to survey the available information for increasing heat and mass transfer rates in the heat exchangers of absorption machines. Emphasis is placed on the hydrodynamic characteristics of falling liquid films in absorbers and generators. The following topics are covered in this paper: 1. Characteristics of thin liquid films over horizontal tubes 2. Characteristics of wavy thin liquid films flowing down the vertical or inclined wall surface 3. Effect of the artificial surface roughness on the heat and mass transfer rates 4. Enhancement in the heat and mass transfer rates by the Marangoni convection 5. Conditions of film breakdown and the minimum wetting rates.

  5. Endovascular vein harvest: systemic carbon dioxide absorption.

    Science.gov (United States)

    Maslow, Andrew M; Schwartz, Carl S; Bert, Arthur; Hurlburt, Peter; Gough, Jeffrey; Stearns, Gary; Singh, Arun K

    2006-06-01

    Endovascular vein harvest (EDVH) requires CO(2) insufflation to expand the subcutaneous space, allowing visualization and dissection of the saphenous vein. The purpose of this study was to assess the extent of CO(2) absorption during EDVH. Prospective observational study. Single tertiary care hospital. Sixty patients (30 EDVH and 30 open-vein harvest) undergoing isolated coronary artery bypass graft surgery. Hemodynamic, procedural, and laboratory data were collected prior to (baseline), during, and at it the conclusion (final) of vein harvesting. Data were also collected during cardiopulmonary bypass (CPB). Data were compared by using t tests, analysis of variance, and correlation statistics when needed. There were significant increases in arterial CO(2) (PaCO(2), 35%) and decreases in pH (1.35%) during EDVH. These were associated with increases in heart rate, mean blood pressure, and cardiac output. Within the EDVH group, greater elevations (>10 mmHg) in PaCO2 were more likely during difficult harvest procedures, and these patients exhibited greater increase in heart rate. Elevated CO(2) persisted during CPB, requiring higher systemic gas flows and greater use of phenylephrine to maintain desired hemodynamics. EDVH was associated with systemic absorption of CO(2). Greater absorption was more likely in difficult procedures and was associated with greater hemodynamic changes requiring medical therapy.

  6. Absorption toward Red BL Lac Objects

    Science.gov (United States)

    Stocke, J. T.; Rector, T. A.

    Based upon the prototypical high-z molecular absorber, PKS 1413+135, we present a summary of properties and search strategies for new high-z absorbers. It is suspicious that two of the four high-z molecular absorbers are BL Lac Objects (PKS 1413+135 & B2 0218+357), suggesting a link between the presence of the foreground absorber and the low equivalent width emission lines of BL Lacs. Also, based upon a new optical absorption line study of radio-selected BL Lac Objects (Stocke & Rector 1997), we find a large overabundance of intervening Mg II absorption line systems in these objects compared to quasars, which also seems to link low equivalent width emission lines to the presence of foreground absorption. Not only does this suggest that the optical characteristics of BL Lacs can be created by microlensing due to stars associated with foreground absorbing gas but also that red BL Lacs are a rich sample to search for new examples of foreground absorbers.

  7. The absorption spectrum of cis-azobenzene.

    Science.gov (United States)

    Vetráková, Ľubica; Ladányi, Vít; Al Anshori, Jamaludin; Dvořák, Pavel; Wirz, Jakob; Heger, Dominik

    2017-12-06

    Azobenzene is a prototypical photochromic molecule existing in two isomeric forms, which has numerous photochemical applications that rely on a precise knowledge of the molar absorption coefficients (ε). Careful analysis revealed that the previously reported absorption spectra of the "pure" isomers were in fact mutually contaminated by small amounts of the other isomer. Therefore, the absorption spectra of both trans- and cis-azobenzene in methanol were re-determined at temperatures of 5-45 °C. The thermodynamically more stable trans-azobenzene was prepared by warming the solution in the dark. To obtain the spectrum of cis-azobenzene three methods were used, which gave consistent results within the limits of error. The method based on the subtraction of derivative spectra coupled with a global analysis of the spectra recorded during thermal cis-trans isomerization is shown to give slightly more reliable results than the method using isomeric ratios determined by 1 H-NMR. The described methods are readily generalizable to other azobenzene derivatives and to other photochromic systems. The practical implication of the re-determined ε values is demonstrated by a very high precision of spectrophotometric species analysis in azobenzene isomeric mixtures. The new ε values imply that the previously reported quantum yields must be revised.

  8. Wavelength mismatch effect in electromagnetically induced absorption

    Energy Technology Data Exchange (ETDEWEB)

    Bharti, Vineet [Department of Physics, Indian Institute of Science, Bangalore 560012 (India); Wasan, Ajay [Department of Physics, Indian Institute of Technology, Roorkee 247667 (India); Natarajan, Vasant [Department of Physics, Indian Institute of Science, Bangalore 560012 (India)

    2016-07-15

    We present a theoretical investigation of the phenomenon of electromagnetically induced absorption (EIA) in a 4-level system consisting of vee and ladder subsystems. The four levels are coupled using one weak probe field, and two strong control fields. We consider an experimental realization using energy levels of Rb. This necessitates dealing with different conditions of wavelength mismatch—near-perfect match where all three wavelengths are approximately equal; partial mismatch where the wavelength of one control field is less than the other fields; and complete mismatch where all three wavelengths are unequal. We present probe absorption profiles with Doppler averaging at room temperature to account for experiments in a room temperature Rb vapor cell. Our analysis shows that EIA resonances can be studied using Rydberg states excited with diode lasers. - Highlights: • Wavelength mismatch effect is investigated in electromagnetically induced absorption (EIA). • An experimental realization of 4-level vee + ladder system using energy levels of rubidium atom is presented. • EIA resonances are studied under different conditions of wavelength mismatch. • Possibility of observation of EIA using Rydberg states excited with diode lasers.

  9. Coherent perfect absorption in photonic structures

    CERN Document Server

    Baldacci, Lorenzo; Tredicucci, Alessandro

    2016-01-01

    The ability to drive a system with an external input is a fundamental aspect of light-matter interaction. The coherent perfect absorption (CPA) phenomenon extends to the general multibeam interference phenomenology the well known critical coupling concepts. This interferometric control of absorption can be employed to reach full delivery of optical energy to nanoscale systems such as plasmonic nanoparticles, and multi-port interference can be used to enhance the absorption of a nanoscale device when it is embedded in a strongly scattering system, with potential applications to nanoscale sensing. Here we review the two-port CPA in reference to photonic structures which can resonantly couple to the external fields. A revised two-port theory of CPA is illustrated, which relies on the Scattering Matrix formalism and is valid for all linear two-port systems with reciprocity. Through a semiclassical approach, treating two-port critical coupling conditions in a non-perturbative regime, it is demonstrated that the st...

  10. THE ABSORPTION OF ADRENALIN AFTER INTRATRACHEAL INJECTION.

    Science.gov (United States)

    Auer, J; Gates, F L

    1916-06-01

    In the preceding pages we have submitted evidence which shows that a simple intratracheal injection of a solution in a normally breathing rabbit penetrates within a few seconds to the alveoli, chiefly those of the left lower lobe; that absorption is rapid and well maintained; and that the procedure may be repeated effectively a number of times even with a substance like adrenalin which decreases absorption. It was also shown that absorption of adrenalin from the lung could be obtained at a time when double the dose given intramuscularly exerted no blood pressure effect whatever, and that absorption could still take place after the development of pulmonary edema, when there was an undoubted dilution of the injected solution with a serum-containing liquid and when a diminution of the absorptive field had occurred. The solution injected, after reaching the alveoli, is probably largely taken up by the capillaries of the pulmonary veins. This is indicated by the great rapidity with which an intratracheal injection of adrenalin may cause a rise of blood pressure. In numerous instances, for example, the pressure began to rise less than 5 seconds after the completion of an injection, equaling and even surpassing in rapidity of effect an intramuscular injection. Absorption by the lymphatics probably plays a secondary part, an assumption rendered all themore likely if we consider that lymph nodes are interpolated in the lymphatic pulmonary path, where the bed of the lymph stream becomes greatly widened and the current slowed. Injection into the lungs, however, offers another advantage due to the vascular arrangement of the absorbing field which could be of value therapeutically. Absorption of liquids injected into the lung probably takes place largely through the capillaries of the pulmonary veins; to a slight extent possibly through the capillaries of the bronchial veins which empty partly into the pulmonary veins, partly into the azygos veins; and probably some absorption

  11. Optical absorption of charged excitons in semiconducting carbon nanotubes

    DEFF Research Database (Denmark)

    Rønnow, Troels Frimodt; Pedersen, Thomas Garm; Cornean, Horia

    2012-01-01

    In this article we examine the absorption coefficient of charged excitons in carbon nanotubes. We investigate the temperature and damping dependence of the absorption spectra. We show that the trion peak in the spectrum is asymmetric for temperatures greater than approximately 1 K whereas...... the absorption peak arising from excitons is symmetric. We expect the positive and negative trion absorption line shapes to be identical, independently of the chiral index (n,m)....

  12. Laser ultrasonic absorption measurement in fatigue-damaged materials.

    Science.gov (United States)

    Luxenburger, S; Arnold, W

    2002-05-01

    Changes in the materials microstructure caused by fatigue processes affect the ultrasonic absorption. Thus, quantitative measurement of the ultrasonic absorption should provide an indirect measure of fatigue damage. In this paper we present a study of the ultrasonic absorption in fatigue-damaged metals using the reverberation technique in combination with laser-based ultrasound. The reverberation technique allows one to measure absorption independently of scattering.

  13. A microscopic description of sound absorption in the atmosphere

    Science.gov (United States)

    Bass, H. E.

    1976-01-01

    The various mechanisms which contribute to sound absorption in the atmosphere are identified and a technique for computing the contribution from each is presented. The similarities between sound absorption, laser fluorescence measurements, and the opto-acoustic effect are discussed. Finally, experimental sound absorption results are compared to predictions to test the microscopic energy transfer approach.

  14. Temperature dependence of the HNO3 UV absorption cross sections

    Science.gov (United States)

    Burkholder, James B.; Talukdar, Ranajit K.; Ravishankara, A. R.; Solomon, Susan

    1993-01-01

    The temperature dependence of the HNO3 absorption cross sections between 240 and 360 K over the wavelength range 195 to 350 nm has been measured using a diode array spectrometer. Absorption cross sections were determined using both (1) absolute pressure measurements at 298 K and (2) a dual absorption cell arrangement in which the absorption spectrum at various temperatures is measured relative to the room temperature absorption spectrum. The HNO3 absorption spectrum showed a temperature dependence which is weak at short wavelengths but stronger at longer wavelengths which are important for photolysis in the lower stratosphere. The 298 K absorption cross sections were found to be larger than the values currently recommended for atmospheric modeling (DeMore et al., 1992). Our absorption cross section data are critically compared with the previous measurements of both room temperature and temperature-dependent absorption cross sections. Temperature-dependent absorption cross sections of HNO3 are recommended for use in atmospheric modeling. These temperature dependent HNO3 absorption cross sections were used in a two-dimensional dynamical-photochemical model to demonstrate the effects of the revised absorption cross sections on loss rate of HNO3 and the abundance of NO2 in the stratosphere.

  15. Enhancing effect of bile salts on gastrointestinal absorption of insulin ...

    African Journals Online (AJOL)

    Purpose: To investigate the effect of co-administration of two absorption enhancing bile alts, sodium glycocholate (NaGc) and sodium salicylate (NaSal), on insulin absorption via intestinal targeted delivery system. Methods: Insulin (10 IU/kg), associated with and without absorption enhancers (5 % enhancer solution of ...

  16. Is oral absorption of vigabatrin carrier-mediated?

    DEFF Research Database (Denmark)

    Nøhr, M. K.; Juul, R. V.; Thale, Z. I.

    2015-01-01

    The aim of the study was to investigate the intestinal transport mechanisms responsible for vigabatrin absorption in rats by developing a population pharmacokinetic (PK) model of vigabatrin oral absorption. The PK model was used to investigate whether vigabatrin absorption was carrier-mediated an...

  17. Page 1 Ultrasonic absorption in carboxylic acids 46; annular rubber ...

    Indian Academy of Sciences (India)

    Figure 1a shows that the measured ultrasonic absorption for the oxalic acid dihydrate, benzoic acid and succinic acid increases with increase in the concentration of the solute, reaches a maximum (the concentration at which the absorption maximum occurs is. Figure 1. Absorption vs concentration of carboxylic acids in ...

  18. 44th Annual Anomalous Absorption Conference

    Energy Technology Data Exchange (ETDEWEB)

    Beg, Farhat

    2014-03-03

    Conference Grant Report July 14, 2015 Submitted to the U. S. Department of Energy Attn: Dr. Sean Finnegan By the University of California, San Diego 9500 Gilman Drive La Jolla, California 92093 On behalf of the 44th Annual Anomalous Absorption Conference 8-13 June 2014, in Estes Park, Colorado Support Requested: $10,100 Amount expended: $3,216.14 Performance Period: 1 March 20 14 to 28 February 20 15 Principal Investigator Dr. Farhat Beg Center for Energy Research University of California, San Diego 9500 Gilman Drive La Jolla, California 92093-0417 858-822-1266 (telephone) 858-534-4543 (fax) fbeg@ucsd.edu Administrative Point of Contact: Brandi Pate, 858-534-0851, blpate®ucsd.edu I. Background The forty-fourth Anomalous Absorption Conference was held in Estes Park, Colorado from June 5-8, 2014 (aac2014.ucsd.edu). The first Anomalous Absorption Conference was held in 1971 to assemble experts in the poorly understood area of laser-plasma absorption. The goal of that conference was to address the anomalously large laser absorption seen in plasma experiments with respect to the laser absorption predicted by linear plasma theory. Great progress in this research area has been made in the decades since that first meeting, due in part to the scientific interactions that have occurred annually at this conference. Specifically, this includes the development of nonlinear laser-plasma theory and the simulation of laser interactions with plasmas. Each summer since that first meeting, this week-long conference has been held at unique locations in North America as a scientific forum for intense scientific exchanges relevant to the interaction of laser radiation with plasmas. Responsibility for organizing the conference has traditional rotated each year between the major Inertial Confinement Fusion (ICF) laboratories and universities including LANL, LLNL, LLE, UCLA UC Davis and NRL. As the conference has matured over the past four decades, its technical footprint has expanded

  19. Friction energy absorption in fiber reinforced composites

    Science.gov (United States)

    Brimhall, Thomas Jay

    Energy absorption of fiber reinforced composite structures is of interest to the automotive industry as their specific energy absorption (SEA), i.e. the energy absorption capability per unit mass, is higher than many metallic counterparts. However, the SEA of composite structures has been observed to decrease under dynamic crush loading when compared with quasi-static compression. This is different from metallic structures. For example, carbon fiber/vinyl ester composite crush tubes crushed at 2.0 m/sec were observed to have SEA of 23.8 J/gm, a decrease in SEA of 6.6 J/gm or 21.7% compared with quasi-statically loaded SEA of 30.4 J/gm. Glass fiber/vinyl ester composite crush tubes were investigated with quasi-static compression and energy-absorbing modes were identified. The observed energy absorbing modes included tube corner splitting, composite delamination, matrix damage due to bending, and sliding friction of the composite with the plug type crush trigger. These same energy absorbing modes were observed in quasi-statically compressed and dynamically crashed carbon/vinyl ester composite crush tubes. Energy absorption attributable to corner splitting at quasi-static compression was estimated using standard tensile test results. Corner splitting was estimated to absorb less that 1% of the total energy absorbed by both the glass fiber composite and the carbon fiber composite crush tubes. Energy absorption attributable to delamination was estimated using the mode II (shear mode) strain energy release rate obtained using the end notch flexure (ENF) test. Under quasi-static compression, the glass fiber composite delamination SEA was found to be 1.31 J/gm or 6.4% of the total tube SEA. For carbon fiber composite crush tubes, the delamination SEA was found to be 0.84 J/gm or 2.8%f the total tube SEA. Experiments seemed to suggest that sliding friction played an important role in the energy absorption of composite crush tubes. In an attempt to separate the sliding

  20. Intestinal Water Absorption Varies with Expected Dietary Water Load among Bats but Does Not Drive Paracellular Nutrient Absorption.

    Science.gov (United States)

    Price, Edwin R; Brun, Antonio; Gontero-Fourcade, Manuel; Fernández-Marinone, Guido; Cruz-Neto, Ariovaldo P; Karasov, William H; Caviedes-Vidal, Enrique

    2015-01-01

    Rapid absorption and elimination of dietary water should be particularly important to flying species and were predicted to vary with the water content of the natural diet. Additionally, high water absorption capacity was predicted to be associated with high paracellular nutrient absorption due to solvent drag. We compared the water absorption rates of sanguivorous, nectarivorous, frugivorous, and insectivorous bats in intestinal luminal perfusions. High water absorption rates were associated with high expected dietary water load but were not highly correlated with previously measured rates of (paracellular) arabinose clearance. In conjunction with these tests, we measured water absorption and the paracellular absorption of nutrients in the intestine and stomach of vampire bats using luminal perfusions to test the hypothesis that the unique elongated vampire stomach is a critical site of water absorption. Vampire bats' gastric water absorption was high compared to mice but not compared to their intestines. We therefore conclude that (1) dietary water content has influenced the evolution of intestinal water absorption capacity in bats, (2) solvent drag is not the only driver of paracellular nutrient absorption, and (3) the vampire stomach is a capable but not critical location for water absorption.

  1. An inulin-type fructan enhances calcium absorption primarily via an effect on colonic absorption in humans

    Science.gov (United States)

    Calcium absorption efficiency and bone mineral mass are increased in adolescents who regularly consume inulin-type fructans (ITF). The mechanism of action in increasing absorption is unknown but may be related to increased colonic calcium absorption. We conducted a study in young adults designed to ...

  2. Confocal light scattering and absorption spectroscopic microscopy

    Science.gov (United States)

    Qiu, Le; Vitkin, Edward; Salahuddin, Saira; Zaman, Munir M.; Andersson, Charlotte; Freedman, Steven D.; Hanlon, Eugene B.; Itzkan, Irving; Perelman, Lev T.

    2008-04-01

    We have developed a novel optical method for observing submicron intracellular structures in living cells which is called confocal light absorption and scattering spectroscopic (CLASS) microscopy. It combines confocal microscopy, a well-established high-resolution microscopic technique, with light scattering spectroscopy (LSS). CLASS microscopy requires no exogenous labels and is capable of imaging and continuously monitoring individual viable cells, enabling the observation of cell and organelle functioning at scales on the order of 100 nm. In addition, it provides not only size information but also information about the biochemical and physical properties of the cell.

  3. A transient absorption study of allophycocyanin

    Indian Academy of Sciences (India)

    Unknown

    A transient absorption study of allophycocyanin. 619 bb gb se ia. AAA ρε ε ε. ) (. 1. 1. 0. −. −. = −=∆. , dd gb se ia cc gb se ia ρε ε ε ρε ε ε. ) (. ) (. 3. 3. 2. 2. −. −. +. −. −. +. , ee gb se ia ρε ε ε. ) (. 4. 4. −. −. +. , where. 4. 3. 2. 1 gb gb gb gb gb ε ε ε ε ε. +. +. +. = ,. )0(. 1. 0 aa gb. A ρε. = , and ee dd cc bb aa aa ρ ρ ρ ρ ρ ρ. +. +. +. +. = )0(.

  4. Absorption and dispersion of ultrasonic waves

    CERN Document Server

    Herzfeld, Karl F; Massey, H S W; Brueckner, Keith A

    1959-01-01

    Absorption and Dispersion of Ultrasonic Waves focuses on the influence of ultrasonics on molecular processes in liquids and gases, including hydrodynamics, energy exchange, and chemical reactions. The book first offers information on the Stokes-Navier equations of hydrodynamics, as well as equations of motion, viscosity, formal introduction of volume viscosity, and linearized wave equation for a nonviscous fluid. The manuscript then ponders on energy exchange between internal and external degrees of freedom as relaxation phenomenon; effect of slow energy exchange on sound propagation; differe

  5. Oil absorption in mesoporous silica particles

    Directory of Open Access Journals (Sweden)

    Radislav Filipović

    2010-12-01

    Full Text Available Mesoporous silica particles were prepared from highly basic sodium silicate solutions, having different silica modulus and SiO2 concentrations, by adding sulphuric acid at different temperatures. Pore structure of prepared silica particles (aggregates is strongly influenced by processing conditions and easy controllable in broad range of the specific surface area, pore size, pore volume and size distribution. It is shown that there is a clear correlation between volume of absorbed oil and processing parameters used in preparation of silica aggregates. Thus, oil absorption is higher in the samples prepared from sodium silicate solution with higher SiO2 concentration and at higher synthesis temperature.

  6. Lithium absorption by the rabbit gall-bladder

    DEFF Research Database (Denmark)

    Hansen, C P; Holstein-Rathlou, N H; Skøtt, O

    1991-01-01

    Lithium (Li+) absorption across the low-resistance epithelium of the rabbit gall-bladder was studied in order to elucidate possible routes and mechanisms of Li+ transfer. Li+ at a concentration of 0.4 mM in both mucosal and serosal media did not affect isosmotic mucosa-to-serosa fluid absorption...... was elicited from the mucosal side and was not accounted for by compensatory Li+ absorption; water and Na+ absorption rates decreased nearly in parallel. The effects of 0.4 mM amiloride and of substitution with 20 mM Li+ were only partly additive. It is concluded that Li+ absorption in the rabbit gall...

  7. Study on Absorption Signal Interference of Gas Concentration Measurement Using Laser Absorption Spectroscopy

    Directory of Open Access Journals (Sweden)

    Maeng Saerom

    2016-01-01

    Full Text Available In order to optimize the combustion condition of the combustion system, it is important to know the information of the physical properties which vary during combustion. Gas concentration and temperature are the major target properties but it is difficult to measure exactly at combustion system. In this paper, a distributed feedback diode laser which wavelength is tunable in accordance with a function generator’s output wave is applied to realize the laser absorption spectroscopy measurement. A concentration measuring test for 99% CO2 gas was performed as basic experiment and major experiments were conducted on separation of interfered absorption signals at CO2 and CO mixed condition.

  8. Medication absorption considerations in patients with postpyloric enteral feeding tubes.

    Science.gov (United States)

    McIntyre, Chelsey M; Monk, Heather M

    2014-04-01

    The gastrointestinal absorption sites of medications administered via postpyloric enteral feeding tubes were examined. Many issues must be considered when administering medications via the postpyloric route, including interactions with enteral feeds, additional toxicities, and the concern of whether the medication will be absorbed. Despite the potential clinical significance of this information, data regarding the gastrointestinal site of absorption for most medications are lacking. Gastrointestinal absorption sites for all drugs for which requests for information on absorption sites were received at our institution since 2008 (n = 124) were evaluated by reviewing the package insert, consulting tertiary references, conducting primary literature searches, or contacting the drug manufacturer. Seventy (56.5%) of the 124 drugs reviewed had information available regarding the site of absorption. Just 2 drugs required acid for absorption and thus should be administered only through the stomach, while 2 other drugs were found to bind extensively to tubing and should not be administered in this manner. For 3 drugs, increased absorption may occur when they are administered directly into the small bowel. Seven medications had decreased absorption when administered directly to the small bowel, and 10 drugs were clearly not absorbed when administered through either the duodenal or the jejunal route. The implications of absorption site should be considered for all patients receiving medications via postpyloric feeding tubes. Several medications cannot be administered through alternative routes because gastric acid is needed for their absorption, the medications may bind to the tubing, or drug absorption is altered at the intestinal site.

  9. Possibilities of testing capillary absorption on microcores

    Directory of Open Access Journals (Sweden)

    Čeh Arpad

    2016-01-01

    Full Text Available During inspection of reinforced concrete structures from the aspect of durability evaluation of concrete, the present methods generally use the test results obtained by the sophisticated and expensive equipment, which are usually not universal purpose, ie. they can be used only for one segment of durability evaluation of the concrete. This way any additional information about the condition of concrete is valuable, especially if it is not require an additional testing with special equipment. Tests of concrete and reinforced concrete with microcore drilling is considered to be a semi- destructive method, which slightly damages the structure itself, and it is primarily used for testing carbonation, density and absorption of concrete. The paper presents the results of capillary absorption according to SRPS EN 480-5 on standard-size samples and on the microcores extracted from cube form samples with edge length of 20 cm. In the article the testing results of penetration of water under pressure are also presented on the same samples, on which we previously gained microcores. These tests were carried out on with concrete mixtures designed for the most demanding exposure classes according to EN 206-1 and using a variety of additives that are known to affect the structure of pores and consequently also the durability of a hardened concrete.

  10. Quantum absorption refrigerator with trapped ions

    Science.gov (United States)

    Gan, Jaren; Maslennikov, Gleb; Hablützel Marrero, Roland; Ding, Shiqian; Nimmrichter, Stefan; Roulet, Alexandre; Dai, Jibo; Scarani, Valerio; Matsukevich, Dzmitry

    2017-04-01

    We report on an experimental realization of a quantum absorption refrigerator in a system of the three trapped 171Yb+ ions. The normal modes of motion are coupled by a trilinear Hamiltonian a† bc + h . c . and represent ``hot'', ``work'' and ``cold'' bodies of the refrigerator. We investigate the equilibrium properties of the refrigerator, and demonstrate the absorption refrigeration effect with the modes being prepared in thermal states. We also investigate the coherent dynamics and steady state properties of such a system away from equilibrium operation. We compare the cooling capabilities of thermal versus squeezed thermal states prepared in the work mode as a quantum resource for cooling. Finally, we exploit the coherent dynamics of the system and demonstrate single-shot cooling in the refrigerator. By stopping the evolution in the right moment, we show a significant advantage in cooling as compared to both the steady state and equilibrium performance. This research is supported by the National Research Foundation, Prime Minister's Office, Singapore and the Ministry of Education, Singapore under the Research Centres of Excellence programme.

  11. Multiexciton absorption in CdSe nanocrystals

    Science.gov (United States)

    Franceschetti, Alberto; Zhang, Yong

    2009-03-01

    Efficient multiple-exciton generation (MEG) has been recently reported in semiconductor nanocrystals. In this process, a single absorbed photon generates two or more electron-hole pairs. The MEG efficiency has so far been evaluated assuming that the change (bleaching) of the absorption spectrum due to MEG is linearly proportional to the number of excitons (NX) that are present in the nanocrystal. We have examined this assumption using atomistic pseudopotential calculations for colloidal CdSe nanocrystals ranging in size from 3 to 4.6 nm. We found that the bleaching of the first absorption peak, δα1S, depends non-linearly on NX, due to carrier-carrier interactions. When a single exciton is present in the nanocrystal, the 1S exciton peak is already 65-75% bleached. This non-linearity mandates an upper bound of 1.5 to the value of the normalized bleaching that can be attributed to MEG, significantly smaller than the limit of 2.0 predicted by the linear scaling assumption. Thus, measured values of the normalized bleaching in excess of 1.5 in CdSe nanocrystals cannot be due entirely to MEG, but must originate in part from other mechanisms.

  12. Combined "dual" absorption and fluorescence smartphone spectrometers.

    Science.gov (United States)

    Arafat Hossain, Md; Canning, John; Ast, Sandra; Cook, Kevin; Rutledge, Peter J; Jamalipour, Abbas

    2015-04-15

    A combined "dual" absorption and fluorescence smartphone spectrometer is demonstrated. The optical sources used in the system are the white flash LED of the smartphone and an orthogonally positioned and interchangeable UV (λex=370  nm) and blue (λex=450  nm) LED. The dispersive element is a low-cost, nano-imprinted diffraction grating coated with Au. Detection over a 300 nm span with 0.42 nm/pixel resolution was carried out with the camera CMOS chip. By integrating the blue and UV excitation sources into the white LED circuitry, the entire system is self-contained within a 3D printed case and powered from the smartphone battery; the design can be scaled to add further excitation sources. Using a customized app, acquisition of absorption and fluorescence spectra are demonstrated using a blue-absorbing and green-emitting pH-sensitive amino-naphthalimide-based fluorescent probe and a UV-absorbing and blue-emitting Zn2+-sensitive fluoro-ionophore.

  13. Water Absorption Behavior of Hemp Hurds Composites

    Directory of Open Access Journals (Sweden)

    Nadezda Stevulova

    2015-04-01

    Full Text Available In this paper, water sorption behavior of 28 days hardened composites based on hemp hurds and inorganic binder was studied. Two kinds of absorption tests on dried cube specimens in deionized water bath at laboratory temperature were performed. Short-term (after one hour water immersion and long-term (up to 180 days water absorption tests were carried out to study their durability. Short-term water sorption behavior of original hemp hurds composites depends on mean particle length of hemp and on binder nature. The comparative study of long-term water sorption behavior of composites reinforced with original and chemically modified hemp hurds in three reagents confirmed that surface treatment of filler influences sorption process. Based on evaluation of sorption curves using a model for composites based on natural fibers, diffusion of water molecules in composite reinforced with original and chemically modified hemp hurds is anomalous in terms of the Fickian behavior. The most significant decrease in hydrophility of hemp hurds was found in case of hemp hurds modified by NaOH and it relates to change in the chemical composition of hemp hurds, especially to a decrease in average degree of cellulose polymerization as well as hemicellulose content.

  14. Water Absorption Behavior of Hemp Hurds Composites

    Science.gov (United States)

    Stevulova, Nadezda; Cigasova, Julia; Purcz, Pavol; Schwarzova, Ivana; Kacik, Frantisek; Geffert, Anton

    2015-01-01

    In this paper, water sorption behavior of 28 days hardened composites based on hemp hurds and inorganic binder was studied. Two kinds of absorption tests on dried cube specimens in deionized water bath at laboratory temperature were performed. Short-term (after one hour water immersion) and long-term (up to 180 days) water absorption tests were carried out to study their durability. Short-term water sorption behavior of original hemp hurds composites depends on mean particle length of hemp and on binder nature. The comparative study of long-term water sorption behavior of composites reinforced with original and chemically modified hemp hurds in three reagents confirmed that surface treatment of filler influences sorption process. Based on evaluation of sorption curves using a model for composites based on natural fibers, diffusion of water molecules in composite reinforced with original and chemically modified hemp hurds is anomalous in terms of the Fickian behavior. The most significant decrease in hydrophility of hemp hurds was found in case of hemp hurds modified by NaOH and it relates to change in the chemical composition of hemp hurds, especially to a decrease in average degree of cellulose polymerization as well as hemicellulose content.

  15. ABSORPTION MEASURE DISTRIBUTION IN Mrk 509

    Energy Technology Data Exchange (ETDEWEB)

    Adhikari, T. P.; Różańska, A.; Sobolewska, M. [Nicolaus Copernicus Astronomical Center, Polish Academy of Sciences, Bartycka 18, 00-716, Warsaw (Poland); Czerny, B., E-mail: tek@camk.edu.pl [Center for Theoretical Physics, Polish Academy of Sciences, Al. Lotnikow 32/46 02-668, Warsaw (Poland)

    2015-12-20

    In this paper we model the observed absorption measure distribution (AMD) in Mrk 509, which spans three orders of magnitude in ionization level with a single-zone absorber in pressure equilibrium. AMD is usually constructed from observations of narrow absorption lines in radio-quiet active galaxies with warm absorbers. We study the properties of the warm absorber in Mrk 509 using recently published broadband spectral energy distribution observed with different instruments. This spectrum is an input in radiative transfer computations with full photoionization treatment using the titan code. We show that the simplest way to fully reproduce the shape of AMD is to assume that the warm absorber is a single zone under constant total pressure. With this assumption, we found theoretical AMD that matches the observed AMD determined on the basis of the 600 ks reflection grating spectrometer XMM-Newton spectrum of Mrk 509. The softness of the source spectrum and the important role of the free–free emission breaks the usual degeneracy in the ionization state calculations, and the explicit dependence of the depths of AMD dips on density open a new path to the density diagnostic for the warm absorber. In Mrk 509, the implied density is of the order of 10{sup 8} cm{sup −3}.

  16. Absorption heat pump for space applications

    Science.gov (United States)

    Nguyen, Tuan; Simon, William E.; Warrier, Gopinath R.; Woramontri, Woranun

    1993-01-01

    In the first part, the performance of the Absorption Heat Pump (AHP) with water-sulfuric acid and water-magnesium chloride as two new refrigerant-absorbent fluid pairs was investigated. A model was proposed for the analysis of the new working pairs in a heat pump system, subject to different temperature lifts. Computer codes were developed to calculate the Coefficient of Performance (COP) of the system with the thermodynamic properties of the working fluids obtained from the literature. The study shows the potential of water-sulfuric acid as a satisfactory replacement for water-lithium bromide in the targeted temperature range. The performance of the AHP using water-magnesium chloride as refrigerant-absorbent pair does not compare well with those obtained using water-lithium bromide. The second part concentrated on the design and testing of a simple ElectroHydrodynamic (EHD) Pump. A theoretical design model based on continuum electromechanics was analyzed to predict the performance characteristics of the EHD pump to circulate the fluid in the absorption heat pump. A numerical method of solving the governing equations was established to predict the velocity profile, pressure - flow rate relationship and efficiency of the pump. The predicted operational characteristics of the EHD pump is comparable to that of turbomachinery hardware; however, the overall efficiency of the electromagnetic pump is much lower. An experimental investigation to verify the numerical results was conducted. The pressure - flow rate performance characteristics and overall efficiency of the pump obtained experimentally agree well with the theoretical model.

  17. Absorption heat pump for space applications

    Science.gov (United States)

    Nguyen, Tuan; Simon, William E.; Warrier, Gopinath R.; Woramontri, Woranun

    1993-12-01

    In the first part, the performance of the Absorption Heat Pump (AHP) with water-sulfuric acid and water-magnesium chloride as two new refrigerant-absorbent fluid pairs was investigated. A model was proposed for the analysis of the new working pairs in a heat pump system, subject to different temperature lifts. Computer codes were developed to calculate the Coefficient of Performance (COP) of the system with the thermodynamic properties of the working fluids obtained from the literature. The study shows the potential of water-sulfuric acid as a satisfactory replacement for water-lithium bromide in the targeted temperature range. The performance of the AHP using water-magnesium chloride as refrigerant-absorbent pair does not compare well with those obtained using water-lithium bromide. The second part concentrated on the design and testing of a simple ElectroHydrodynamic (EHD) Pump. A theoretical design model based on continuum electromechanics was analyzed to predict the performance characteristics of the EHD pump to circulate the fluid in the absorption heat pump. A numerical method of solving the governing equations was established to predict the velocity profile, pressure - flow rate relationship and efficiency of the pump. The predicted operational characteristics of the EHD pump is comparable to that of turbomachinery hardware; however, the overall efficiency of the electromagnetic pump is much lower. An experimental investigation to verify the numerical results was conducted. The pressure - flow rate performance characteristics and overall efficiency of the pump obtained experimentally agree well with the theoretical model.

  18. Time dependent effects of two absorption enhancers on the nasal absorption of growth hormone in rabbits

    DEFF Research Database (Denmark)

    Vermehren, C.; Hansen, Harald S.; Thomsen, M.K.

    1996-01-01

    Enhancer-based drug preparations allow absorption of peptide drugs. We investigated the reversibility with time of nasal absorption of human growth hormone (hGH) induced by the absorption enhancers didecanoylphosphatidylcholine (DDPC) and a-cyclodextrin (a-CD). Rabbits were dosed intranasally...... with enhancer in the absence of hGH at time -3, -1, -0.5 and 0 h. At time zero the same groups of rabbits were dosed with a hGH powder devoid of the enhancers. Values for plasma hGH AUC and C(max) were estimated in order to measure the degree of absorption, and rabbits receiving hGH together with enhancers were...... the tissue. Similar findings were obtained with a-CD alone, whereas a preparation containing only DDPC showed no recovery of leakiness. The effect of a-CD was also investigated in vitro in rabbit nasal mucosa mounted in Ussing chambers. Incubation for 15 min with 1, 3 and 8% a-CD induced a concentration...

  19. Time dependent effects of two absorption enhancers on the nasal absorption of growth hormone in rabbits

    DEFF Research Database (Denmark)

    Vermehren, Charlotte; Hansen, H.S.; Thomsen, M.K.

    1996-01-01

    Enhancer-based drug preparations allow absorption of peptid drugs. We investigated the reversibility with time of nasal absorption of human growth hormone (hGH) induced by the absorption enhancers didecanoylhposphatidylcholine (DDPC) and Ó-cyclodextrin (Ó-CD). Rabbits were dosed intranasally...... with enhancer in the absence of hGH at time -3, -1, -0.5 and 0 h. At time zero the same groups of rabbits were dosed with a hGH powder devoid of the enhancers. Values for plasma hGH AUC and Cmax were estimated in order to measure the degree of absorption, and rabbits receiving hGH together with enhancers were...... the tissue. Similar findings were obtained with Ó-CD alone, whereas a preparation containing only DDPC showed no recovery of leakiness. The effect of Ó-CD was also investigated in vitro in rabbit nasal mucosa mounted in Ussing chambers. Incubation ofr 15 min with 1, 3 and 8% Ó-CD induced a concentration...

  20. Absorption of hydrogen in vanadium, enhanced by ion bombardment; Ionenbeschussunterstuetzte Absorption des Wasserstoffs in Vanadium

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, H.; Lammers, M. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany); Mueller, K.H. [Inst. fuer Technologie- und Wissenstransfer, Soest (Germany)]|[Paderborn Univ. (Gesamthochschule), Soest (Germany). Fachbereich 16 - Elektrische Energietechnik; Kiss, G.; Kemeny, Z. [Technical Univ. Budapest (Hungary)

    1998-12-31

    Prior to hydrogen implantation into vanadium, the vanadium specimen usually is exposed to an activation process and is then heated at 1 atm hydrogen to temperatures between 500 and 600 C, subsequently cooled down in several steps. Within this temperature range, hydrogen solubility increases with declining temperature. A decisive factor determining hydrogen absorption is the fact that at temperatures above 250 C, oxygen desorbs from the material surface and thus no longer inhibits hydrogen absorption. Therefore a different approach was chosen for the experiments reported: Hydrogen absorption under UHV conditions at room temperature. After the usual activation process, the vanadium surface was cleaned by 5 keV Ar{sup +} ion bombardment. Thus oxygen absorption at the specimen surface (and new reactions with oxygen from the remaining gas) could be avoided, or removed. By means of thermal desorption mass spectrometry (TDMS), hydrogen absorption as a function of argon ion dose was analysed. TDMS measurements performed for specimens treated by ion bombardment prior to H{sup 2} exposure showed two H{sup 2} desorption peaks, in contrast to the profiles measured with specimens not exposed to ion bombardment. It is assumed that the ion bombardment disturbs the crystal structure so that further sites for hydrogen absorption are produced. (orig./CB) [Deutsch] Bei der Beladung von Vandium mit Wasserstoff wird ueblicherweise die Probe nach einer Aktivierungsprozedur bei 1 atm Wasserstoff auf Temperaturen im Bereich von 500 bis 600 C hochgeheizt und danach schrittweise abgekuehlt. In diesem Temperaturbereich nimmt die Wasserstoffloeslichkeit mit abnehmender Temperatur zu. Entscheidend fuer die Beladung ist aber auch die Tatsache, dass bei Temperaturen groesser 250 C Sauerstoff von der Oberflaeche desorbiert und dadurch die Absorption von Wasserstoff nicht mehr blockieren kann. Im Rahmen der hier beschriebenen Untersuchungen sollte die Wasserstoffbeladung unter UHV-Bedingungen bei

  1. Hydrothermal treatment and malting of barley improved zinc absorption but not calcium absorption in humans.

    Science.gov (United States)

    Fredlund, K; Bergman, E-L; Rossander-Hulthén, L; Isaksson, M; Almgren, A; Sandberg, A-S

    2003-12-01

    To study whether hydrothermal treatment or malting of barley (cv. Blenheim) improves zinc and calcium absorption in humans. : Two groups of 10 and 12 healthy subjects, respectively, were in a period of 2 months in a fasting state, served two single meals each containing porridge or breakfast cereals prepared from processed or unprocessed (control) barley (60 g). The meals included 200 g of milk, extrinsically labelled with (65)Zn and (47)Ca. Whole-body retention of both minerals was measured. The study was carried out at the Department of Radiation Physics, Sahlgrenska University Hospital, Göteborg. The subjects were recruited among students at the Göteborg University. None dropped out. The activities of (65)Zn and (47)Ca were measured by whole-body counting four to five times over a 4-week period after each meal. Zinc absorption from hydrothermally treated barley porridge, containing 28 mg P as inositol tri- to hexaphosphates (InsP(3)-InsP(6)), was significantly higher (P0.05), 21.1+/-6.8 vs 19.5+/-4.7% (n=12). Zinc absorption from breakfast cereals of malted barley with phytase activity and containing 70 mg P as InsP(3)-InsP(6,) was significantly higher (P0.05). Improvements of zinc absorption in breakfast meals can be achieved by optimised hydrothermal treatment or malting of barley. Calcium absorption was not influenced in the meals in this study. Supported by Semper AB, Sweden, Oy Lahden Polttimo, Finland, the SL-Foundation, Sweden, Swedish National Board for Industrial and Technical Development (NUTEK), the Nordic Industrial Foundation, Swedish Council for Forestry and Agricultural Research (SJFR, project no 50.0306/97).

  2. Assessment of normal incidence absorption performance of sound absorbing materials

    Directory of Open Access Journals (Sweden)

    Farhad Forouharmajd

    2016-01-01

    Full Text Available Aims: The purpose of the present work was to consider the effect of different samples thicknesses on the acoustic absorption coefficient. Materials and Methods: An impedance tube was built with two microphones accordance to ISO-10534 and the American Society for Testing Materials-E1050 standards. For the measurement of absorption, the study was carried for 25 and 30 mm thicknesses of closed cell polyurethane foam, polystyrene, polyvinyl chloride (PVC, rubber, mineral wool, carpet, and glass samples. Measurements were performed by impedance tube and VA-lab4 software. Results: In carpet and mineral wool with more thickness, the absorption was increased but, the carpet with less thickness showed more sound absorption in the frequency range of 1500-3600 Hz. The peak of the absorption coefficient of 25 mm glass was 0.36 that the amount was reduced to 0.2 in the 30 mm thickness. Furthermore, the difference between the peak absorption of two thicknesses in polystyrene sample was equal to 0.29. In fact, polystyrene with less thickness had better sound absorption. The same situation was happened for glass in frequencies of below 4500 Hz with less thickness. Conclusion: Incident sound energy, which is not absorbed, must be reflected, transmitted, or dissipated. The porous materials had a higher absorption coefficient. Carpet and mineral wool samples had the highest absorption coefficient, but the materials such as polyurethane foam, PVC, and rubber had lower sound absorption.

  3. X-ray absorption spectroscopy of semiconductors

    CERN Document Server

    Ridgway, Mark

    2015-01-01

    X-ray Absorption Spectroscopy (XAS) is a powerful technique with which to probe the properties of matter, equally applicable to the solid, liquid and gas phases. Semiconductors are arguably our most technologically-relevant group of materials given they form the basis of the electronic and photonic devices that now so widely permeate almost every aspect of our society. The most effective utilisation of these materials today and tomorrow necessitates a detailed knowledge of their structural and vibrational properties. Through a series of comprehensive reviews, this book demonstrates the versatility of XAS for semiconductor materials analysis and presents important research activities in this ever growing field. A short introduction of the technique, aimed primarily at XAS newcomers, is followed by twenty independent chapters dedicated to distinct groups of materials. Topics span dopants in crystalline semiconductors and disorder in amorphous semiconductors to alloys and nanometric material as well as in-sit...

  4. Acceleration by synchrotron absorption and superluminal sources

    Energy Technology Data Exchange (ETDEWEB)

    Ghisellini, G.; Bodo, G.; Trussoni, E.; Rees, M.J. (Torino Osservatorio Astronomico, Turin (Italy) Cambridge Univ. (England))

    1990-10-01

    A magnetized blob, containing relativistic electrons, can absorb, by the synchrotron process, low-frequency photons emitted by an underlying source. The momentum of the adsorbed photons can accelerate the blob to relativistic velocities. The final bulk Lorentz factor can be as large as required by observations of superluminal sources even if only the low-frequency part of the spectrum of a sub-Eddington central source is used for the acceleration process, and even if the blob contains an equal number of protons and electrons. This is mainly due to the large absorption cross section of the synchrotron process with respect to the electron scattering cross section, but partly because strongly aberrated photons are seen blueshifted in the rest frame of the blob and are less efficiently absorbed, reducing the importance of the braking force due to the radiation drag. 12 refs.

  5. Plasma sprayed coatings for RF wave absorption

    Science.gov (United States)

    Nanobashvili, S.; Matějíček, J.; Žáček, F.; Stőckel, J.; Chráska, P.; Brožek, V.

    2002-12-01

    High requirements for fusion reactor materials and for experimental fusion devices have led within the fusion community to the development and testing of various coatings of the surfaces of in-vessel components and biological shields for microwave heating systems. Based on contacts with ITER, W7X and the Spanish Stellarator TJ-II, IPP Prague has initiated a development, production and test program on various low- Z materials. This paper reports on the production, development and properties of B 4C, Si and Al 2O 3 coatings sprayed by water stabilized plasma. Main focus is on their radio frequency wave reflection properties. Further characterization includes the coating structure by microscopy, phase composition by X-ray diffraction and oxygen content measurement by atomic absorption spectroscopy. The results are discussed with respect to processing conditions as well as potential application.

  6. Plasma sprayed coatings for RF wave absorption

    Energy Technology Data Exchange (ETDEWEB)

    Nanobashvili, S.; Matejicek, J. E-mail: jmatejic@ipp.cas.cz; Zacek, F.; Stockel, J.; Chraska, P.; Brozek, V

    2002-12-01

    High requirements for fusion reactor materials and for experimental fusion devices have led within the fusion community to the development and testing of various coatings of the surfaces of in-vessel components and biological shields for microwave heating systems. Based on contacts with ITER, W7X and the Spanish Stellarator TJ-II, IPP Prague has initiated a development, production and test program on various low-Z materials. This paper reports on the production, development and properties of B{sub 4}C, Si and Al{sub 2}O{sub 3} coatings sprayed by water stabilized plasma. Main focus is on their radio frequency wave reflection properties. Further characterization includes the coating structure by microscopy, phase composition by X-ray diffraction and oxygen content measurement by atomic absorption spectroscopy. The results are discussed with respect to processing conditions as well as potential application.

  7. Ozone absorption in a mechanically stirred reactor

    Directory of Open Access Journals (Sweden)

    LJILJANA TAKIC

    2007-08-01

    Full Text Available Ozone absorption in water was investigated in a mechanically stirred reactor, using both the semi-batch and continuous mode of operation. A model for the precise determination of the volumetric mass transfer coefficient in open tanks without the necessity of the measurement the ozone concentration in the outlet gas was developed. It was found that slow ozone reactions in the liquid phase, including the decomposition of ozone, can be regarded as one pseudo-first order reaction. Under the examined operating conditions, the liquid phase was completely mixed, while mixing in a gas phase can be described as plug flow. The volumetric mass transfer coefficient was found to vary with the square of the impeller speed.

  8. Quasar Absorption Lines and SDSS Galaxies

    Science.gov (United States)

    Shoemaker, Emileigh Suzanne; Scott, Jennifer E.; Oldak, Katarzyna

    2017-01-01

    We present the results of a study of the sightlines of 45 low redshift quasars (0.06 footprint of the Sloan Digital Sky Survey. We use both the SDSS DR12 galaxy photometric data, including photometric redshifts, and the measured properties of the absorbers along with the known absorption characteristics of the intergalactic medium and the circumgalactic medium of galaxies to assign the most probable galaxy matches for each absorber in the sample, using estimated galaxy luminosities and virial radii as a discriminator. We show that the scheme can recover known galaxy-absorber matches found from spectroscopic data and thus provides a method for identifying likely pairs in photometric data sets as well as targets for spectroscopic follow up.

  9. Using Methane Absorption to Probe Jupiter's Atmosphere

    Science.gov (United States)

    1997-01-01

    Mosaics of a belt-zone boundary near Jupiter's equator in near-infrared light moderately absorbed by atmospheric methane (top panel), and strongly absorbed by atmospheric methane (bottom panel). The four images that make up each of these mosaics were taken within a few minutes of each other. Methane in Jupiter's atmosphere absorbs light at specific wavelengths called absorption bands. By detecting light close and far from these absorption bands, Galileo can probe to different depths in Jupiter's atmosphere. Sunlight near 732 nanometers (top panel) is moderately absorbed by methane. Some of the light reflected from clouds deep in Jupiter's troposphere is absorbed, enhancing the higher features. Sunlight at 886 nanometers (bottom panel) is strongly absorbed by methane. Most of the light reflected from the deeper clouds is absorbed, making these clouds invisible. Features in the diffuse cloud layer higher in Jupiter's atmosphere are greatly enhanced.North is at the top. The mosaic covers latitudes -13 to +3 degrees and is centered at longitude 282 degrees West. The smallest resolved features are tens of kilometers in size. These images were taken on November 5th, 1996, at a range of 1.2 million kilometers by the Solid State Imaging system aboard NASA's Galileo spacecraft.The Jet Propulsion Laboratory, Pasadena, CA manages the mission for NASA's Office of Space Science, Washington, DC.This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov. Background information and educational context for the images can be found at URL http://www.jpl.nasa.gov/galileo/sepo

  10. Feedback from Broad Absorption Line Quasars

    Science.gov (United States)

    Chartas, George; Saez, C.

    2008-03-01

    The fraction of the total bolometric energy released over an AGN's lifetime into the ISM and IGM in the form kinetic energy injection scales as the outflow velocity to the third power so we expect that powerful broad absorption line (BAL) quasars may have mass outflow rates that are large enough to influence significantly the formation of the host galaxy and to regulate the growth of the central black hole. One of the most promising radio quiet quasars for studying the properties of the outflow is the lensed BAL quasar APM 08279+5255. The large flux magnification by a factor of about 100 provided by the gravitational lens effect combined with the large redshift (z = 3.91) of the quasar have provided the highest S/N X-ray spectra of a quasar containing X-ray BALs. We present results from recent monitoring observations of APM 08279+5255. performed with the Suzaku, XMM-Newton and Chandra observatories. Significant variability of the X-ray BALs is detected on timescales as short as 4 days (proper time) implying launching radii of about 6 times the Schwarzschild radius. The fitted width of the X-ray absorption troughs imply a large gradient in the outflow velocity of the X-ray absorbers with projected outflow velocities of up to 0.5c. The notch-like shape of the detected X-ray BALs are similar to those produced in recent numerical simulations (i.e. Schurch & Done 2007) that include radiative transfer calculations through highly ionized X-ray absorbers outflowing at near relativistic velocities. We provide preliminary constraints of the outflows properties.

  11. Statistics of cosmological Lyman α absorption

    Science.gov (United States)

    Munshi, Dipak; Coles, Peter; Viel, Matteo

    2012-12-01

    We study the effect of the non-Gaussianity induced by gravitational evolution upon the statistical properties of absorption in quasar (quasi-stellar object) spectra. Using the generic hierarchical ansatz and the lognormal approximation, we derive the analytical expressions for the one-point probability distribution function (PDF) as well as for the joint two-point PDF of transmitted fluxes in two neighbouring quasi-stellar objects. These flux PDFs are constructed in three dimensions as well as in projection (i.e. in two dimensions). The PDFs are constructed by relating the lower-order moments (i.e. cumulants and cumulant correlators) of the fluxes to the three-dimensional neutral hydrogen distribution, which is, in turn, expressed as a function of the underlying dark matter distribution. Next, the lower-order moments are modelled using a generating function formalism in the context of a minimal tree-model for the higher-order correlation hierarchy. These different approximations give nearly identical results for the range of redshifts probed, and we also find very good agreement between our predictions and the outputs of hydrodynamical simulations. The formalism developed here for the joint statistics of flux-decrements concerning two lines of sight can be extended to multiple lines of sight, which could be particularly important for the three-dimensional reconstruction of the cosmic web from the spectra of quasi-stellar objects (e.g. in the Baryon Oscillation Spectroscopic Survey). These statistics probe the underlying projected neutral hydrogen field and are thus linked to hotspots of absorption. The results for the PDF and the bias presented here use the same functional forms of scaling functions that have previously been employed for the modelling of other cosmological observations, such as the Sunyaev-Zel'dovich effect.

  12. Absorption of americium compounds in the respiratory tract.

    Science.gov (United States)

    Blanchardon, Eric; Davesne, Estelle; Paquet, François; Bailey, Michael

    2014-11-01

    To improve the dosimetry of incorporated americium (Am) and to contribute to radiation protection by characterizing the absorption kinetics of inhaled Am compounds. In vitro dissolution tests, animal experiments and human contamination cases published in the literature were reviewed. The data were analyzed with biokinetic models consistent with the current publications of the International Commission on Radiological Protection. Material-specific dissolution parameter values with consequent assignment to absorption Types are proposed as well as representative central values for the different chemical forms of Am. The absorption of Am oxide is consistent with the moderate absorption Type M while Am nitrate appears more soluble. Am associated with plutonium oxide usually follows its slow absorption Type S. However, the large variability observed stresses the value of investigating the specific absorption kinetics for Am compounds which represent a significant risk of internal exposure.

  13. Triple-band metamaterial absorption utilizing single rectangular hole

    Science.gov (United States)

    Kim, Seung Jik; Yoo, Young Joon; Kim, Young Ju; Lee, YoungPak

    2017-01-01

    In the general metamaterial absorber, the single absorption band is made by the single meta-pattern. Here, we introduce the triple-band metamaterial absorber only utilizing single rectangular hole. We also demonstrate the absorption mechanism of the triple absorption. The first absorption peak was caused by the fundamental magnetic resonance in the metallic part between rectangular holes. The second absorption was generated by induced tornado magnetic field. The process of realizing the second band is also presented. The third absorption was induced by the third-harmonic magnetic resonance in the metallic region between rectangular holes. In addition, the visible-range triple-band absorber was also realized by using similar but smaller single rectangular-hole structure. These results render the simple metamaterials for high frequency in large scale, which can be useful in the fabrication of metamaterials operating in the optical range.

  14. Standard Practice for Evaluating Solar Absorptive Materials for Thermal Applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 This practice covers a testing methodology for evaluating absorptive materials used in flat plate or concentrating collectors, with concentrating ratios not to exceed five, for solar thermal applications. This practice is not intended to be used for the evaluation of absorptive surfaces that are (1) used in direct contact with, or suspended in, a heat-transfer liquid, (that is, trickle collectors, direct absorption fluids, etc.); (2) used in evacuated collectors; or (3) used in collectors without cover plate(s). 1.2 Test methods included in this practice are property measurement tests and aging tests. Property measurement tests provide for the determination of various properties of absorptive materials, for example, absorptance, emittance, and appearance. Aging tests provide for exposure of absorptive materials to environments that may induce changes in the properties of test specimens. Measuring properties before and after an aging test provides a means of determining the effect of the exposure. 1.3 Th...

  15. Energy absorption and propagation in laser-created sparks.

    Science.gov (United States)

    Bindhu, C V; Harilal, S S; Tillack, M S; Najmabadi, F; Gaeris, A C

    2004-06-01

    The energy absorption and laser propagation characteristics of air and argon sparks at one atmosphere have been investigated. To create the sparks, 532 nm pulses from a frequency doubled Q-switched Nd : YAG laser are used. We employed 2 ns gated fast photography for studying the time evolution of the kernel at early times. Optical emission spectroscopy is used to infer temperature and density of the sparks. Significant energy absorption by the plasma is observed just above the breakdown threshold. The energy absorption and propagation in the spark indicated that argon plasma is more absorptive than air plasma. The absorption of the spark increases with laser energy, and at higher energies absorption saturation is observed. A spiky behavior is observed in the transmitted temporal profiles of lasers at higher energies and this is explained as due to the formation of a self-regulating regime.

  16. Directional perfect absorption using deep subwavelength low permittivity films

    CERN Document Server

    Luk, Ting S; Kim, Iltai; Feng, Simin; Jun, Young Chul; Liu, Sheng; Wright, Jeremy B; Brener, Igal; Catrysse, Peter B; Fan, Shanhui; Sinclair, Michael B

    2014-01-01

    We experimentally demonstrate single beam directional perfect absorption (to within experimental accuracy) of p-polarized light in the near-infrared using unpatterned, deep subwavelength films of indium tin oxide (ITO) on Ag. The experimental perfect absorption occurs slightly above the epsilon-near-zero (ENZ) frequency of ITO where the permittivity is less than one. Remarkably, we obtain perfect absorption for films whose thickness is as low as ~1/50th of the operating free-space wavelength and whose single pass attenuation is only ~ 5%. We further derive simple analytical conditions for perfect absorption in the subwavelength-film regime that reveal the constraints that the ITO permittivity must satisfy if perfect absorption is to be achieved. Then, to get a physical insight on the perfect absorption properties, we analyze the eigenmodes of the layered structure by computing both the real-frequency/complex-wavenumber and the complex-frequency/real-wavenumber modal dispersion diagrams. These analyses allow u...

  17. Effect of idler absorption in pulsed optical parametric oscillators.

    Science.gov (United States)

    Rustad, Gunnar; Arisholm, Gunnar; Farsund, Øystein

    2011-01-31

    Absorption at the idler wavelength in an optical parametric oscillator (OPO) is often considered detrimental. We show through simulations that pulsed OPOs with significant idler absorption can perform better than OPOs with low idler absorption both in terms of conversion efficiency and beam quality. The main reason for this is reduced back conversion. We also show how the beam quality depends on the beam width and pump pulse length, and present scaling relations to use the example simulations for other pulsed nanosecond OPOs.

  18. Mechanochemistry of graphene: Tuning ion absorption on graphene via strain

    Science.gov (United States)

    Hu, Yonghong; Wu, Yunyi; Yan, Zhong; Mao, Caixia; Xue, Li; Sun, Tieyu; Wang, Yu

    2017-12-01

    The ultra-high specific surface area of graphene endows this two-dimensional material with an excellent capacity of ion absorption. Here we show that the ion absorption properties of graphene can be tailored via mechanical deformation. By using density function theory (DFT) analysis, we found that strain could enhance the ion absorption capacity of graphene. Our results provide perspective for the development of graphene-based electrochemical devices, such as stress difference battery and mechanochemistry sensors with graphene electrodes.

  19. MNC knowledge transfer, subsidiary absorptive capacity and HRM

    OpenAIRE

    Minbaeva, Dana; Pedersen, Torben; Bjoerkman, Ingmar; Carl F Fey; Park, H J

    2014-01-01

    Based on a sample of 169 subsidiaries of multinational corporations (MNCs) operating in the USA, Russia, and Finland, this paper investigates the relationship between MNC subsidiary human resource management (HRM) practices, absorptive capacity, and knowledge transfer. First, we examine the relationship between the application of specific HRM practices and the level of the absorptive capacity. Second, we suggest that absorptive capacity should be conceptualized as being comprised of both empl...

  20. Nitrogen-induced absorption of oxygen in the Herzberg continuum

    Science.gov (United States)

    Shardanand, MR.

    1977-01-01

    Total absorption of O2 induced by collisions with N2 has been measured at room temperature in the Hersberg continuum using a one meter normal incidence grating monochromator. The enhanced absorption is ascribed to the formation of O2-O2 and O2-N2 dimers. The interaction constants for these dimers are determined and utilized to investigate their effect on the absorption of solar radiation in the stratosphere.

  1. Continuous Light Absorption Photometer (CLAP) Final Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Jefferson, Anne [National Oceanic and Atmospheric Administration (NOAA), Washington, DC (United States)

    2014-05-01

    The Continuous Light Absorption Photometer (CLAP) measures the aerosol absorption of radiation at three visible wavelengths; 461, 522, and 653 nanometers (nm). Data from this measurement is used in radiative forcing calculations, atmospheric heating rates, and as a prediction of the amount of equivalent black carbon in atmospheric aerosol and in models of aerosol semi-direct forcing. Aerosol absorption measurements are essential to modeling the energy balance of the atmosphere.

  2. Retrieving complex surface impedances from statistical absorption coefficients

    DEFF Research Database (Denmark)

    Mondet, Boris Jean-Francois; Brunskog, Jonas; Jeong, Cheol-Ho

    2017-01-01

    In room acoustic simulations the surface materials are commonly represented with energy parameters, such as the absorption and scattering coefficients, which do not carry phase information. This paper presents a method to transform statistical absorption coefficients into complex surface impedances...... coefficients, prior information about the absorber of interest can be used as constraints, which is shown to help determine the correct impedance from absorption coefficient. Further stability and sensitivity investigations indicate that the method presented constitutes an efficient solution to convert sound...

  3. Atmospheric greenhouse gases detection by optical similitude absorption spectroscopy

    OpenAIRE

    Anselmo, Christophe

    2016-01-01

    This thesis concerns the theoretical and experimental development of a new methodology for greenhouse gases detection based on the optical absorption. The problem relies on the unambiguous retrieval of a gas concentration from differential absorption measurements, in which the spectral width of the light source is wider than one or several absorption lines of the considered target gas given that the detection is not spectrally resolved. This problem could lead to the development of a robust r...

  4. Dielectric Characteristics and Microwave Absorption of Graphene Composite Materials

    National Research Council Canada - National Science Library

    Rubrice, Kevin; Castel, Xavier; Himdi, Mohamed; Parneix, Patrick

    2016-01-01

    .... Carbon-based nanoparticles belong to these types of materials. Among these, graphene presents some distinctive features for electromagnetic radiation absorption and thus microwave isolation applications...

  5. Novel Instrument to Measure Aerosol Fluorescence, Absorption, and Scattering Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Picarro, Inc proposes to develop the first cavity ringdown spectroscopy (CRDS) system to measure fluorescence, absorption, and scattering properties of atmospheric...

  6. SAFARI 2000 Cloud Absorption Radiometer BRDF, Dry Season 2000

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: The Cloud Absorption Radiometer (CAR) is an airborne multi-wavelength scanning radiometer that can perform several functions including determining the...

  7. Temporal evolutional absorption behaviors of graphene under Landau quantization

    Science.gov (United States)

    Hamedi, H. R.; Sahrai, M.

    2017-02-01

    We investigate the evolutional absorption behaviors of Landau-quantized graphene structure based on the transient solution to the density matrix equations of the motion. The impact of various system parameters on temporal evolution of probe absorption is studied. In addition, the required times for switching the high-absorption case to the zero-absorption (transparency) of a probe field is discussed. Due to unusual optical and electronic characteristics of graphene resulting from linear, massless dispersion of electrons near the Dirac point and the chiral character of electron states, our study may have potential applications in telecommunication, biomedicine, and optical information processing and may cause significant impact on technological applications.

  8. CO2 Capture from Flue Gas by Phase Transitional Absorption

    Energy Technology Data Exchange (ETDEWEB)

    Liang Hu

    2009-06-30

    A novel absorption process called Phase Transitional Absorption was invented. What is the Phase Transitional Absorption? Phase Transitional Absorption is a two or multi phase absorption system, CO{sub 2} rich phase and CO{sub 2} lean phase. During Absorption, CO{sub 2} is accumulated in CO{sub 2} rich phase. After separating the two phases, CO{sub 2} rich phase is forward to regeneration. After regeneration, the regenerated CO{sub 2} rich phase combines CO{sub 2} lean phase to form absorbent again to complete the cycle. The advantage for Phase Transitional Absorption is obvious, significantly saving on regeneration energy. Because CO{sub 2} lean phase was separated before regeneration, only CO{sub 2} rich phase was forward to regeneration. The absorption system we developed has the features of high absorption rate, high loading and working capacity, low corrosion, low regeneration heat, no toxic to environment, etc. The process evaluation shows that our process is able to save 80% energy cost by comparing with MEA process.

  9. MNC Knowledge Transfer, Subsidiary Absorptive Capacity and HRM

    DEFF Research Database (Denmark)

    Minbaeva, Dana; Pedersen, Torben; Björkman, Ingmar

    2014-01-01

    of specific HRM practices and the level of the absorptive capacity. Second, we suggest that absorptive capacity should be conceptualized as being comprised of both employees’ ability and motivation. Further, results indicate that both ability and motivation (absorptive capacity) are needed to facilitate......Based on a sample of 169 subsidiaries of multinational corporations (MNCs) operating in the USA, Russia, and Finland, this paper investigates the relationship between MNC subsidiary HRM practices, absorptive capacity and knowledge transfer. First, we examine the relationship between the application...

  10. The Hyperspectral Absorption Sensor - Advantages and challenges of continuous, in situ absorption coefficient measurements

    Science.gov (United States)

    Wollschläger, J.; Röttgers, R.; Petersen, W.; Zielinski, O.

    2016-12-01

    The marine environment is a highly dynamic system and rapid changes can occur on both spatial and temporal scales. This is especially true for the phytoplankton, which forms the basis of the marine food web. Comprehensive monitoring and investigation of its often patchy distribution and seasonal succession requires sensors which are fast, can be used in situ, and are automatable to reduce operational costs. Optical sensors fulfil all of these requirements. Due to its variety of (sometimes group-specific) photosynthetic and photoprotective pigments, phytoplankton has a considerable influence on the water's inherent and apparent optical properties. This offers the possibility to obtain information about the phytoplankton present by measuring these properties, for example the absorption coefficients of the water at the photosynthetic active wavelengths. However, common obstacles for obtaining high quality absorption coefficient measurements are the often low concentration of absorbing material present as well as errors introduced by light scattering on particles. These problems can be overcome by instruments taking advantage of integrating cavities, like the point-source integrating cavity absorption meter (PSICAM). The Hyperspectral Absorption Sensor (HyAbS) is the result of an attempt to combine the advantages of the PSICAM approach with the high resolution of continuous measurements. Its setup and working principle is described, and challenges and potential solutions with respect to its long-term automated operation are highlighted. This includes the replacement of the dye-based calibration of the instrument by a solid standard calibration. Finally, also results from field test with respect to phytoplankton investigation are given.

  11. Inhibiting Cholesterol Absorption During Lactation Programs Future Intestinal Absorption of Cholesterol in Adult Mice.

    Science.gov (United States)

    Dimova, Lidiya G; de Boer, Jan Freark; Plantinga, Josee; Plösch, Torsten; Hoekstra, Menno; Verkade, Henkjan J; Tietge, Uwe J F

    2017-08-01

    In nematodes, the intestine senses and integrates early life dietary cues that lead to lifelong epigenetic adaptations to a perceived nutritional environment-it is not clear whether this process occurs in mammals. We aimed to establish a mouse model of reduced dietary cholesterol availability from maternal milk and investigate the consequences of decreased milk cholesterol availability, early in life, on the metabolism of cholesterol in adult mice. We blocked intestinal absorption of cholesterol in milk fed to newborn mice by supplementing the food of dams (for 3 weeks between birth and weaning) with ezetimibe, which is secreted into milk. Ezetimibe interacts with the intestinal cholesterol absorption transporter NPC1l1 to block cholesterol uptake into enterocytes. Characterization of these offspring at 24 weeks of age showed a 27% decrease in cholesterol absorption (P < .001) and reduced levels of Npc1l1 messenger RNA and protein, but not other cholesterol transporters, in the proximal small intestine. We observed increased histone H3K9me3 methylation at positions -423 to -607 of the proximal Npc1l1 promoter in small intestine tissues from 24-week-old offspring fed ezetimibe during lactation, compared with controls. These findings show that the early postnatal mammalian intestine functions as an environmental sensor of nutritional conditions, responding to conditions such as low cholesterol levels by epigenetic modifications of genes. Further studies are needed to determine how decreased sterol absorption for a defined period might activate epigenetic regulators; the findings of our study might have implications for human infant nutrition and understanding and preventing cardiometabolic disease. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

  12. Calcium absorption from fortified ice cream formulations compared with calcium absorption from milk.

    Science.gov (United States)

    van der Hee, Regine M; Miret, Silvia; Slettenaar, Marieke; Duchateau, Guus S M J E; Rietveld, Anton G; Wilkinson, Joy E; Quail, Patricia J; Berry, Mark J; Dainty, Jack R; Teucher, Birgit; Fairweather-Tait, Susan J

    2009-05-01

    Optimal bone mass in early adulthood is achieved through appropriate diet and lifestyle, thereby protecting against osteoporosis and risk of bone fracture in later life. Calcium and vitamin D are essential to build adequate bones, but calcium intakes of many population groups do not meet dietary reference values. In addition, changes in dietary patterns are exacerbating the problem, thereby emphasizing the important role of calcium-rich food products. We have designed a calcium-fortified ice cream formulation that is lower in fat than regular ice cream and could provide a useful source of additional dietary calcium. Calcium absorption from two different ice cream formulations was determined in young adults and compared with milk. Sixteen healthy volunteers (25 to 45 years of age), recruited from the general public of The Netherlands, participated in a randomized, reference-controlled, double-blind cross-over study in which two test products and milk were consumed with a light standard breakfast on three separate occasions: a standard portion of ice cream (60 g) fortified with milk minerals and containing a low level (3%) of butter fat, ice cream (60 g) fortified with milk minerals and containing a typical level (9%) of coconut oil, and reduced-fat milk (1.7% milk fat) (200 mL). Calcium absorption was measured by the dual-label stable isotope technique. Effects on calcium absorption were evaluated by analysis of variance. Fractional absorption of calcium from the 3% butterfat ice cream, 9% coconut oil ice cream, and milk was 26%+/-8%, 28%+/-5%, and 31%+/-9%, respectively, and did not differ significantly (P=0.159). Results indicate that calcium bioavailability in the two calcium-fortified ice cream formulations used in this study is as high as milk, indicating that ice cream may be a good vehicle for delivery of calcium.

  13. Linoleic acid absorption in the unanesthetized rat: mechanism of transport and influence of luminal factors on absorption.

    Science.gov (United States)

    Chow, S L; Hollander, D

    1979-04-01

    Linoleic acid intestinal absorption was studied in the unanesthetized rat. At low (21-1260 micrometer) intraluminal concentrations, absorption took place by facilitated diffusion; while at high (1.26-2.5 mM) concentrations, simple diffusion was the predominant mechanism of transport. At low concentrations (840 micrometer), the equimolar additions of oleic, linolenic, and arachidonic acids or lecithin inhibited the absorption of linoleic acid. Substitution of potassium for sodium in the buffer solution, substitution of Tween 80 for sodium taurocholate, or decrease in the hydrogen ion concentration all resulted in decreased rate of linoleic acid absorption. Increase in sodium taurocholate concentration, or perfusate flow rate increased linoleic acid's absorption. These experiments demonstrate that linoleic acid is absorbed by a concentration-dependent dual mechanism of transport. The absorption rate is modified by the pH, surfactant type and concentration, the simultaneous presence of other polyunsaturated fatty acids, and the thickness of the unstirred water layer.

  14. Energy absorption of braided composite tubes

    Science.gov (United States)

    Beard, Shawn Joseph

    In this investigation, a model was developed for simulating the crushing behavior and predicting the energy absorption characteristics of braided composite tubes. The crushing model uses the finite element code ABAQUS along with a material module that describes the constitutive behavior of the braid material. The material module contains a three-dimensional description of the braid geometry, which is used to calculate the effective stiffnesses of a representative volume. The stiffness calculations include the effects of nonlinear shear, damage accumulation, and scissoring and jamming of the braider tows. A stiffness reduction scheme, based on the predicted failure mode, is used to account for tow and resin failure throughout the representative volume. Scissoring of the braider tows results in an increase in the overall effective compliance until jamming occurs. To facilitate the model development, extensive coupon tests and tube crushing experiments were conducted. Coupon tests were conducted on braided flat plaques to help characterize the damage mechanisms occurring and to obtain the initial stiffnesses for verifying the proposed model. The braided flat plaques were made using 80k Akzo Nobel Fortafil carbon fiber tows for both the axial and braider tows, and Hetron 922 epoxy-vinyl ester resin for the matrix. Crushing tests were conducted on braided carbon fiber/epoxy-vinyl ester composite tubes with both circular and square cross-sections. All tests were conducted quasi-statically, and plug-type initiators were used to trigger the progressive crushing. The braided tubes were made using 80k Akzo Nobel Fortafil carbon fiber tows for the axial tows, 12k Hercules Grafil 34-700 carbon fiber tows for the braider tows, and Hetron 922 epoxy-vinyl ester resin for the matrix. The energy absorption characteristics are significantly affected by the fiber architecture of the tube and the fillet radius of the initiator plug. In order to verify the proposed model, simulation

  15. Light absorption by organic carbon from wood combustion

    Science.gov (United States)

    Chen, Y.; Bond, T. C.

    2010-02-01

    Carbonaceous aerosols affect the radiative balance of the Earth by absorbing and scattering light. While black carbon (BC) is highly absorbing, some organic carbon (OC) also has significant absorption, especially at near-ultraviolet and blue wavelengths. To the extent that OC absorbs visible light, it may be a non-negligible contributor to positive direct aerosol radiative forcing. Quantification of that absorption is necessary so that radiative-transfer models can evaluate the net radiative effect of OC. In this work, we examine absorption by primary OC emitted from solid fuel pyrolysis. We provide absorption spectra of this material, which can be related to the imaginary refractive index. This material has polar character but is not fully water-soluble: more than 92% was extractable by methanol or acetone, compared with 73% for water and 52% for hexane. Water-soluble OC contributes to light absorption at both ultraviolet and visible wavelengths. However, a larger portion of the absorption comes from OC that is extractable only by methanol. Absorption spectra of water-soluble OC are similar to literature reports. We compare spectra for material generated with different wood type, wood size and pyrolysis temperature. Higher wood temperature is the main factor creating OC with higher absorption; changing wood temperature from a devolatilizing state of 210 °C to a near-flaming state of 360 °C causes about a factor of four increase in mass-normalized absorption at visible wavelengths. A clear-sky radiative transfer model suggests that, despite the absorption, both high-temperature and low-temperature OC result in negative top-of-atmosphere radiative forcing over a surface with an albedo of 0.19 and positive radiative forcing over bright surfaces. Unless absorption by real ambient aerosol is higher than that measured here, it probably affects global average clear-sky forcing very little, but could be important in energy balances over bright surfaces.

  16. Light absorption by organic carbon from wood combustion

    Directory of Open Access Journals (Sweden)

    Y. Chen

    2010-02-01

    Full Text Available Carbonaceous aerosols affect the radiative balance of the Earth by absorbing and scattering light. While black carbon (BC is highly absorbing, some organic carbon (OC also has significant absorption, especially at near-ultraviolet and blue wavelengths. To the extent that OC absorbs visible light, it may be a non-negligible contributor to positive direct aerosol radiative forcing. Quantification of that absorption is necessary so that radiative-transfer models can evaluate the net radiative effect of OC.

    In this work, we examine absorption by primary OC emitted from solid fuel pyrolysis. We provide absorption spectra of this material, which can be related to the imaginary refractive index. This material has polar character but is not fully water-soluble: more than 92% was extractable by methanol or acetone, compared with 73% for water and 52% for hexane. Water-soluble OC contributes to light absorption at both ultraviolet and visible wavelengths. However, a larger portion of the absorption comes from OC that is extractable only by methanol. Absorption spectra of water-soluble OC are similar to literature reports. We compare spectra for material generated with different wood type, wood size and pyrolysis temperature. Higher wood temperature is the main factor creating OC with higher absorption; changing wood temperature from a devolatilizing state of 210 °C to a near-flaming state of 360 °C causes about a factor of four increase in mass-normalized absorption at visible wavelengths. A clear-sky radiative transfer model suggests that, despite the absorption, both high-temperature and low-temperature OC result in negative top-of-atmosphere radiative forcing over a surface with an albedo of 0.19 and positive radiative forcing over bright surfaces. Unless absorption by real ambient aerosol is higher than that measured here, it probably affects global average clear-sky forcing very little, but could be important in energy balances over bright

  17. Vehicle effects on human stratum corneum absorption and skin penetration.

    Science.gov (United States)

    Zhang, Alissa; Jung, Eui-Chang; Zhu, Hanjiang; Zou, Ying; Hui, Xiaoying; Maibach, Howard

    2017-05-01

    This study evaluated the effects of three vehicles-ethanol (EtOH), isopropyl alcohol (IPA), and isopropyl myristate (IPM)-on stratum corneum (SC) absorption and diffusion of the [(14)C]-model compounds benzoic acid and butenafine hydrochloride to better understand the transport pathways of chemicals passing through and resident in SC. Following application of topical formulations to human dermatomed skin for 30 min, penetration flux was observed for 24 h post dosing, using an in vitro flow-through skin diffusion system. Skin absorption and penetration was compared to the chemical-SC (intact, delipidized, or SC lipid film) binding levels. A significant vehicle effect was observed for chemical skin penetration and SC absorption. IPA resulted in the greatest levels of intact SC/SC lipid absorption, skin penetration, and total skin absorption/penetration of benzoic acid, followed by IPM and EtOH, respectively. For intact SC absorption and total skin absorption/penetration of butenafine, the vehicle that demonstrated the highest level of sorption/penetration was EtOH, followed by IPA and IPM, respectively. The percent doses of butenafine that were absorbed in SC lipid film and penetrated through skin in 24 h were greatest for IPA, followed by EtOH and IPM, respectively. The vehicle effect was consistent between intact SC absorption and total chemical skin absorption and penetration, as well as SC lipid absorption and chemical penetration through skin, suggesting intercellular transport as a main pathway of skin penetration for model chemicals. These results suggest the potential to predict vehicle effects on skin permeability with simple SC absorption assays. As decontamination was applied 30 min after chemical exposure, significant vehicle effects on chemical SC partitioning and percutaneous penetration also suggest that skin decontamination efficiency is vehicle dependent, and an effective decontamination method should act on chemical solutes in the lipid domain.

  18. Cost reduction in absorption chillers: Phase 2

    Energy Technology Data Exchange (ETDEWEB)

    Leigh, R.W.

    1989-02-01

    A research program at Brookhaven National Laboratory (BNL) has addressed the possibility of dramatically lowering the first costs of absorption chillers through lowered material intensity and the use of lower cost materials, primarily in the heat exchangers which make up the bulk of the operating components of these systems. This must be done while retaining the best performance characteristics available today, a gross design point coefficient of performance (COP) of 1.3 and a net design (seasonal) average COP of 1.0 (0.90) in a directly fired, double effect unit. We have investigated several possible routes to these goals, and here report on these findings, focusing on the areas that appear most promising. The candidate technologies include the use of polymer film heat exchangers in several applications, the use of thin strips of new, corrosion resistant alloys to replace thicker, less impervious metals in applications exposed to gas flames, and copper or cupro-nickel foils in contact with system water. The use of such materials is only possible in the context of new heat exchanger and system designs, which are also discussed. To lend focus, we have concentrated on a directly fired double effect system providing capacity only. If successful, these techniques will also find wide applicability in heat pumps, cogeneration systems, solar cooling, heat recovery and chemical process heat transfer. 46 refs., 24 figs., 22 tabs.

  19. GASTROINTESTINAL TRACT AND IRON ABSORPTION: A REVIEW

    Directory of Open Access Journals (Sweden)

    Gladys O. LATUNDE-DADA

    2009-07-01

    Full Text Available

    Iron is an important element in many metabolic processes. The bioavailability of iron is a function of solubilization and reduction of Fe3+ in the stomach, hydrolysis, neutralization, ligand complexes and transport through the mucus layer of the intestine. The bioavailibility of non-heme Fe is determined by enhancers of iron absorption such as meat, amino acids, organic acids, antagonized by the inhibitors as bran, phytate and fibre. Haem Fe is absorbed directly as an intact metalloprotein porphyrin complex. The pathways of inorganic Fe into the mucosa cell Include endocytosis, electrogenic fatty acid mediated transcellular pathway, nonspecific paracellular permeation ar probably facilitated transcellular diffusion. The redox model proposes the reduction of Fe3+ by a transplasma membrane ferric reductase in lhe duodenal mucosa and the translocation of the Fe2+ across the cell probably by the nonesterified fatty acid. The mucin-mobilferrin-integrin pathway on the other hand involves the delivery of Fe-mucin complex in the lumen to the integrins of mucosa surface for translocation lo mobllferrin in the cytosol. The transfer of absorbed Fe iron from the mucosa into the blood is dependent on a number of regulatory intracellular and systemic factors

  20. Absorption heat transformers and an industrial application

    Energy Technology Data Exchange (ETDEWEB)

    Horuz, Ilhami; Kurt, Bener [University of Uludag, Faculty of Engineering and Architecture, Department of Mechanical Engineering, 16059 Gorukle, Bursa (Turkey)

    2010-10-15

    Absorption Heat Transformer (AHT) systems are devices with the unique capability of raising the temperature of low or moderately warm waste heat sources to more useful levels. The study includes an investigation to analyze the AHT systems using water-lithium bromide solutions with water as the refrigerant. First, a basic AHT system was described, the operating sequence was explained and thermodynamic system analysis was presented. Next, an application of the AHT system to an industrial company was analyzed. A computer code was prepared to determine the effect of different parameters on the AHT system performance and the results were presented in graphical form. Additionally, it was shown that how the basic AHT system could be modified to increase the COP and the heat transfer at the absorber, in other words, the hot process water produced. The system performance data were presented in a tabular form for different system modifications from the base system for comparison. It was proven that, by applying different modifications, the COP could be increased by 14.1%, the heat transfer at the absorber by 158.5% and the hot process water produced by 3.59% compared to the basic AHT system. (author)

  1. Two-Photon Absorption Based Nanoscopic Velocimeter

    Science.gov (United States)

    Wang, Audrey; Abdalrahman, Akrm; Deng, Jianyu; Wang, Guiren

    2017-11-01

    Most velocimeters in micro/nanofluidics rely on particles as flow tracers, such as micro Particle Image Velocimetry (μPIV). However, for many microflows, such as electrokinetic and near wall flow, magnetophoresis, acoustophoresis, photophoresis and thermophoresis, particles have different velocity from their surrounding fluids. Although most molecular tracer based velocimeters can use neutral dye to measure average velocity, their temporal and spatial resolution are limited. Stimulated emission depletion (STED) based laser-induced fluorescence photobleaching anemometer (LIFPA), i.e. STED-LIFPA has achieved 70 nm spatial resolution. However, STED nanoscopy is very complicated for most users. Here we developed a two-photon absorption LIFPA (TP-LIFPA), which is relatively easier to operate. TP-LIFPA can take advantage of the two-photon microscopy to increase spatial resolution. We use a femtolaser to excite a dye. A microcapillary tube is used to test the feasibility of TP-LIFPA. TP-LIFPA can successfully measure the velocity profile in the capillary. The resolution of TP-LIFPA is estimated to be about 90 nm. The work indicates TP-LIFPA is a new promising nanoscopic velocimeter for interfacial flows, especially within 100 nm at the interfacial area between two phases in the future. The work was supported by NSF under Grant No. MRI CBET-1040227.

  2. Model of moisture absorption by adhesive joint

    Science.gov (United States)

    Bonilla Mora, Veronica; Mieloszyk, Magdalena; Ostachowicz, Wieslaw

    2018-01-01

    Adhesive joints offer many advantages over traditional mechanical joining systems. Nonetheless, their use is limited since they can be adversely affected by extreme temperatures and humidity conditions. Moisture contamination (even 1-3% of the sample weight) in an adhesive can alter its tensile strength and compromise the structural integrity of the joint. Moisture absorption processes can be monitored using methods based on fibre Bragg grating sensors embedded in the adhesive material. In the present paper, a finite element model of an adhesive joint between composite elements was analysed using the commercial code Abaqus™. The investigation contains two main parts: a thermal analysis and a hygro-mechanical analysis. The achieved results were verified using experimental investigation results for a sample with embedded fibre Bragg grating sensors that were applied to monitor the moisture-induced strains in the adhesive joint. The achieved numerical results show good agreement with the experimental ones for all considered analyses. The presented models can also be used for the determination of moisture content in an adhesive layer especially in a range of 1.5-2.5% of the water content.

  3. Accidental death via intravaginal absorption of methamphetamine.

    Science.gov (United States)

    Jones, Prentiss; Mutsvunguma, Romeo; Prahlow, Joseph A

    2014-06-01

    In this paper a drug fatality that involved an unintended drug delivery route is described. The decedent, a 23-year-old female in custody in a county jail on suspicion of a felony drug offense, was discovered in a holding cell unconscious and unresponsive. Following unsuccessful cardiopulmonary resuscitation attempts she was pronounced dead at the scene. At autopsy a wad of multiple small loosely wrapped plastic packages held together with another layer of clear plastic was found in the decedent's vagina. The smaller plastic packages contained an off-white pasty substance that was later identified as methamphetamine. Toxicological testing of specimens collected during autopsy revealed methamphetamine in the decedent's subclavian blood, vitreous fluid, and urine at extremely high concentrations (42.6, 20.1, and 771 mg/L, respectively). Amphetamine, the active metabolite of methamphetamine, was also present in the subclavian blood, vitreous fluid, and urine at significant concentrations (1.3, 0.5, and 20.4 mg/L, respectively). The cause of death was attributed to toxic effects of methamphetamine and the manner of death was ruled accidental. This report suggests that lethal concentrations of methamphetamine may be distributed to the systemic circulation via intravaginal absorption.

  4. rock physics investigation of seismic wave absorption in reservoir ...

    African Journals Online (AJOL)

    Admin

    the inverse quality factor using first principles of rock inelastic properties and modeling seismic absorption in rock with partial gas saturation ... higher the gas saturation, the higher the absorption, and the poorer the seismic image. The signature of gas .... were effected in two separate MATLAB codes specially written for this ...

  5. Carbon Dioxide Absorption in a Membrane Contactor with Color Change

    Science.gov (United States)

    Pantaleao, Ines; Portugal, Ana F.; Mendes, Adelio; Gabriel, Joaquim

    2010-01-01

    A pedagogical experiment is described to examine the physical absorption of gases, in this case carbon dioxide, in a hollow fiber membrane contactor (HFMC) where the absorption concentration profile can be followed by a color change. The HFMC is used to teach important concepts and can be used in interesting applications for students, such as…

  6. Training and business performance: the mediating role of absorptive capacities.

    Science.gov (United States)

    Hernández-Perlines, Felipe; Moreno-García, Juan; Yáñez-Araque, Benito

    2016-01-01

    Training has been the focus of considerable conceptual and empirical attention but is considered a relevant factor for competitive edge in companies because it has a positive impact on business performance. This study is justified by the need for deeper analysis of the process involving the transfer of training into performance. This paper's originality lies in the implementation of the absorptive capacities approach as an appropriate conceptual framework for designing a model that reflects the connection between training and business performance through absorptive capacities. Based on the above conceptual framework and using the dual methodological implementation, a new method of analyzing the relationship between training and performance was obtained: efforts in training will not lead to performance without the mediation of absorptive. Training turns into performance if absorptive capacities are involved in this process. The suggested model becomes an appropriate framework for explaining the process of transformation of training into organizational performance, in which absorptive capacities play a key role. The findings obtained can go further owing to fs/QCA: of the different absorptive capacities, that of exploitation is a necessary condition to achieve better organizational performance. Therefore, training based on absorptive capacity will guide and facilitate the design of appropriate human resource strategies so that training results in improved performance. This conclusion is relevant for the development of a new facet of absorptive capacities by relating it to training and resulting in first-level implications for human resource management.

  7. Absorption and oxidation of no in ionic liquids

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention concerns the absorption and in situ oxidation of nitric oxide (NO) in the presence of water and oxygen in ionic liquid compositions at ambient temperature.......The present invention concerns the absorption and in situ oxidation of nitric oxide (NO) in the presence of water and oxygen in ionic liquid compositions at ambient temperature....

  8. Meat protein fractions enhance nonheme iron absorption in humans.

    Science.gov (United States)

    Hurrell, Richard F; Reddy, Manju B; Juillerat, Marcel; Cook, James D

    2006-11-01

    The nature of the enhancing effect of muscle tissue on nonheme iron absorption in humans is unclear but thought to be related to muscle proteins. We conducted radioiron absorption studies to compare iron absorption from proteins isolated from beef and chicken muscle with that from freeze-dried beef and chicken muscle and from egg albumin. All meals contained an equivalent amount of protein as part of a semisynthetic liquid formula. Freeze-dried beef and chicken muscle increased iron absorption 180% (P egg albumin. When added to the meal at an equivalent protein level (15 g), the isolated beef protein and the isolated heme-free beef protein with 94 and 98% protein content, respectively, increased iron absorption to the same extent as the native beef muscle. Similarly, when added to the meal at an equivalent protein level (30 g), isolated chicken muscle protein (94% protein) increased iron absorption similarly to native chicken muscle. Iron absorption from the meal containing the isolated heme-free chicken protein, however, was 120% (P extraction and separation procedures. Our results support the hypothesis that the enhancing effect of muscle tissue on iron absorption is mainly protein related but indicate that other factors may also play a role.

  9. High sensitivity probe absorption technique for time-of-flight ...

    Indian Academy of Sciences (India)

    Absorption imaging using a high sensitivity CCD camera gives the size of the expanding cloud and hence ... (LVIS) [2], the peak signal in a 1 mm thick resonant probe beam corresponds to the absorption by 3 × 105 ... used in our atom optics experiments on the reflection of atoms from magnetic thin films [13]. The sensitivity ...

  10. Molecular Dynamics Investigation of Efficient SO2 Absorption by ...

    Indian Academy of Sciences (India)

    ANIRBAN MONDAL

    Abstract. Ionic liquids are appropriate candidates for the absorption of acid gases such as SO2. Six anion- functionalized ionic liquids with different basicities have been studied for SO2 absorption capacity by employ- ing quantum chemical calculations and molecular dynamics (MD) simulations. Gas phase quantum ...

  11. [Spectral absorption coefficients of optically active substances in Lake Dianchi].

    Science.gov (United States)

    Zhang, Hong; Huang, Jia-Zhu; Li, Yun-Mei; Lü, Heng; Wu, Chuan-Qing; Jin, Xin; Wang, Yan-Fei; Yin, Bin

    2011-02-01

    A field investigation in Lake Dianchi was carried out in November, 2009, and a dataset including absorption coefficients and concentration of water components was collected. Absorption properties and its spatial distribution of Lake Dianchi have been systematically analyzed, the results show that: (1) Absorption spectral curve of total particles (a(p)) are similar with that of phytoplankton (a(ph)), which indicates that phytoplankton absorption dominates absorption of total suspended particles; (2) Significant relationships are found between a(ph) (440), a(ph) (624), a(ph) (675) and concentration of chla, and cyanophyta dominats the quantity of the algae in water columns; (3) There are more phytoplankton existed in northern lake than other areas because of higher level of eutrophication. Comparing with other water columns, discrepancies mainly appear as below: (1) The mean value of slope of absorption spectral curve of non-algal particles (S(d)) in Lake Dianchi is much bigger than that in other case-II waters; (2) The mean value of slope of absorption spectral curve of chromophoric dissolved organic matter (CDOM) S(g) in Lake Dianchi is much smaller than that in other case-II waters; (3) Specific absorption of phytoplankton (a(ph)*) at 440 nm and 675 nm is at intermediate level, and a(ph)* value is susceptible to different regions, seasons, population structure of phytoplankton and so on.

  12. Reliability of graphite furnace atomic absorption spectrometry as ...

    African Journals Online (AJOL)

    Purpose: To evaluate the comparative efficiency of graphite furnace atomic absorption spectrometry (GFAAS) and hydride generation atomic absorption spectrometry (HGAAS) for trace analysis of arsenic (As) in natural herbal products (NHPs). Method: Arsenic analysis in natural herbal products and standard reference ...

  13. On sound absorption and thermal properties of non-wovens

    OpenAIRE

    Chen Jin-Jing; Yu Hong-Qin; Guo Zheng; You Jin-Zhang; Song Wen-Fang

    2015-01-01

    Non-woven is widely used as auxiliary materials of automobile industry due to its excellent sound absorption capability and good thermal property. The paper concludes that its density greatly affects sound absorption and thermal resistance, and an aluminum evaporated film can enhance the thermal resistance.

  14. Enhancing organisational absorptive capacity by reframing an outdated suggestion box

    DEFF Research Database (Denmark)

    Kallio, Anne; Bergenholtz, Carsten

    2012-01-01

    The study explores the connection between the organisational and individual level absorptive capacity in the context of shopfloor employees. Most literature on absorptive capacity focuses on the organisational level, while there has been less focus on the social integration mechanisms between the...

  15. improvement to the design of a solid absorption solar refrigerator

    African Journals Online (AJOL)

    user

    The paper presents the highlights of the design of an existing solid absorption solar refrigerator, using CaCl2 stabilised ... design of a new model refrigerator, to improve the refrigerator performance are then presented. Introduction ..... O. C. Iloeje, "Parametric Effects on the Performance of a Solar Powered Solid Absorption.

  16. Optical absorption and fluorescence studies on imidazolium ionic ...

    Indian Academy of Sciences (India)

    Imidazolium ionic liquids; UV-Vis absorption; excitation wavelength-dependent fluorescence; red-edge effect; solvent effect. ... gives rise to the long absorption tail and shifting fluorescence maximum, which appears to be common to most of the imidazolium ionic liquids, is evident from the effect of the conventional solvents.

  17. Moderate cholecalciferol supplementation depresses intestinal calcium absorption in growing dogs

    NARCIS (Netherlands)

    Tryfonidou, M.A.; Stevenhagen, J.J.; Bemd, G.J.C.M. van den; Oosterlaken-Dijksterhuis, M.A.; Deluca, H.F.; Mol, J.A.; Brom, W.E. van den; Leeuwen, J.P.T.M. van; Hazewinkel, H.A.W.

    2002-01-01

    Hormonal regulation of calcium (Ca) absorption was investigated in a cholecalciferol (vitamin D3)supplemented group (hVitD) vs. a control group (cVitD) of growing Great Danes (100 vs. 12.5 μg vitamin D3/kg diet). Although Ca intakes did not differ, fractional Ca absorption was significantly lower in

  18. On sound absorption and thermal properties of non-wovens

    Directory of Open Access Journals (Sweden)

    Chen Jin-Jing

    2015-01-01

    Full Text Available Non-woven is widely used as auxiliary materials of automobile industry due to its excellent sound absorption capability and good thermal property. The paper concludes that its density greatly affects sound absorption and thermal resistance, and an aluminum evaporated film can enhance the thermal resistance.

  19. Rate of water absorption and proximate analysis of different varieties ...

    African Journals Online (AJOL)

    Water absorption and proximate composition of four varieties of maize; sweet corn, pop corn, white corn and yellow corn soaked at different temperatures and time duration were determined. Absorption increased with increase in temperatures and time but generally low at 45°C. The total average rate of hydration at different ...

  20. Analysis of Decentralized Control for Absorption Cycle Heat Pumps

    DEFF Research Database (Denmark)

    Vinther, Kasper; Just Nielsen, Rene; Nielsen, Kirsten Mølgaard

    2015-01-01

    Email Print Request Permissions This paper investigates decentralized control structures for absorption cycle heat pumps and a dynamic nonlinear model of a single-effect LiBr-water absorption system is used as case study. The model has four controllable inputs, which can be used to stabilize...

  1. Nitrogen-vacancy ensemble magnetometry based on pump absorption

    DEFF Research Database (Denmark)

    Ahmadi, Sepehr; El-Ella, Haitham A. R.; Wojciechowski, Adam M.

    2018-01-01

    We demonstrate magnetic-field sensing using an ensemble of nitrogen-vacancy centers by recording the variation in the pump-light absorption due to the spin-polarization dependence of the total ground-state population. Using a 532 nm pump laser, we measure the absorption of native nitrogen-vacancy...... the nitrogen-vacancy concentration and the detection method....

  2. Microwave absorption studies of MgB 2 superconductor

    Indian Academy of Sciences (India)

    Microwave absorption studies have been carried out on MgB2 superconductor using a standard X-band EPR spectrometer. The modulated low-field microwave absorption signals recorded for polycrystalline (grain size ∼ 10m) samples suggested the absence of weak-link character. The field dependent direct microwave ...

  3. Carbonyl Sulfide Isotopologues: Ultraviolet Absorption Cross Sections and Stratospheric Photolysis

    DEFF Research Database (Denmark)

    Danielache, Sebastian Oscar; Nanbu, Shinkoh; Eskebjerg, Carsten

    2009-01-01

    Ultraviolet absorption cross sections of the main and substituted carbonyl sulfide isotopologues were calculated using wavepacket dynamics. The calculated absorption cross section of 16O12C32S is in very good agreement with the accepted experimental spectrum between 190 and 250 nm. Relative to 16O...

  4. UV- Radiation Absorption by Ozone in a Model Atmosphere using ...

    African Journals Online (AJOL)

    UV- radiation absorption is studied through variation of ozone transmittance with altitude in the atmosphere for radiation in the 9.6μm absorption band using Goody's model atmosphere with cubic spline interpolation technique to improve the quality of the curve. The data comprising of pressure and temperature at different ...

  5. The Effect of Phonon Relaxation Process on Absorption Spectra ...

    African Journals Online (AJOL)

    In this work we study the effect of phonon relaxation process on the absorption spectra using the Green's function technique. The Green's function technique which is widely used in many particle problems is used to solve the Kubo formula which describes the optical absorption process. Finally the configurational diagram is ...

  6. [Advances in studies on absorption, distribution, metabolism of flavonoids].

    Science.gov (United States)

    Lv, Peng; Huang, Xiao-Wu; Lv, Qiu-Jun

    2007-10-01

    Plenty of data and tests suggested that flavonoids have strong physiological and pharmacological activities. In this paper, the absorption, distribution and metabolism of flavonoids in gaster, gut and liver were introduced. The research of absorption, distribution and metabolism on flavonoids will provide theoretical basis for developing new drugs of flavoniods.

  7. Kinetics of absorption of carbon dioxide in aqueous ammonia solutions

    NARCIS (Netherlands)

    Derks, P. W. J.; Versteeg, G. F.

    2009-01-01

    In the present work the absorption of carbon dioxide into aqueous ammonia solutions has been studied in a stirred cell reactor, at low temperatures and ammonia concentrations ranging from 0.1 to about 7 kmol m-3. The absorption experiments were carried out at conditions where the so-called pseudo

  8. X-ray absorption near-edge structure (XANES) spectroscopy

    NARCIS (Netherlands)

    Henderson, Grant S.; De Groot, Frank M F; Moulton, Benjamin J A

    2014-01-01

    The previous Reviews in Mineralogy volume on spectroscopic methods (Vol. 18 Spectroscopic Methods in Mineralogy and Geology, Frank C. Hawthorne, ed. 1988), contained a single chapter on X-ray absorption spectroscopy which reviewed aspects of both EXAFS (Extended X-ray Absorption Fine Structure) and

  9. Dietary protein absorption of the small intestine in human neonates

    NARCIS (Netherlands)

    Schaart, Maaike W.; de Bruijn, Adrianus C. J. M.; Tibboel, Dick; Renes, Ingrid B.; van Goudoever, Johannes B.

    2007-01-01

    The intestine plays a key role in the absorption of dietary proteins, which determines growth of human neonates. Bowel resection in the neonatal period brings loss of absorptive and protective surface and may consequently lead to malabsorption of dietary nutrients. However, there are no data on net

  10. Oxalate and sucralose absorption in idiopathic calcium oxalate stone formers.

    Science.gov (United States)

    Knight, John; Jiang, Juquan; Wood, Kyle D; Holmes, Ross P; Assimos, Dean G

    2011-08-01

    To better understand intestinal oxalate transport by correlating oxalate and sucralose absorption in idiopathic calcium oxalate stone formers. Oxalate has been hypothesized to undergo absorption in the large and small intestine by both paracellular and transepithelial transport. Sucralose is a chlorinated sugar that is absorbed by paracellular mechanisms. Idiopathic calcium oxalate stone formers were recruited to provide urine specimens on both a self-selected diet and after a meal containing 90 mg of (13)C(2-)oxalate and 5 g of sucralose, and a stool sample for determination of Oxalobacter formigenes colonization. The 24-hour urine collections were fractionated into the first 6 hours and the subsequent 18 hours. Sucralose and oxalate excretion were measured during these periods and used to estimate absorption. Thirty-eight subjects were evaluated. The majority of both the (13)C(2-)oxalate and sucralose absorption occurred within the 0-6-hour collection. The (13)C(2-)oxalate and sucralose absorptions were significantly correlated at the 0-6 hour, the 6-24 hour, and the total 24-hour time periods (P 15% absorption) also absorbed significantly more sucralose during the 0-6 hour and whole 24-hour time points (P sucralose absorption, may also influence oxalate absorption. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Determination of sedimentation rates and absorption coefficient of ...

    African Journals Online (AJOL)

    DR. MIKE HORSFALL

    In this study, sedimentation rates of insoluble transition metal carbonates are determined. Gamma rays from 60Co source are used to determine the absorption coefficient of these metal carbonates. The results obtained are used to investigate the functional relationship between sedimentation rate and absorption coefficient.

  12. Efficient absorption by monolayer graphene in microring resonator

    Science.gov (United States)

    Liu, Ziyu

    2017-06-01

    We demonstrate a graphene photodetector based on a SOI microring resonator. The absorption of the graphene was enhanced by the resonating, so to improve the detection efficiency by 5 times. The impact of graphene’s position and length on the absorption rate was also been studied. The frequency selective effect shows the potential on spectrum detection and WDM photoelectric conversion.

  13. High durability solar absorptive coating and methods for making same

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Aaron C.; Adams, David P.

    2016-11-22

    The present invention relates to solar absorptive coatings including a ceramic material. In particular, the coatings of the invention are laser-treated to further enhance the solar absorptivity of the material. Methods of making and using such materials are also described.

  14. Pavement sound absorption measurements in the U.S.

    Science.gov (United States)

    2012-08-19

    In the U.S., the topic of pavement sound absorption in regard to tire-pavement noise has shown increased interest and research over the last several years. Four types of pavement sound absorption measurements with various applications are discussed: ...

  15. Lithium absorption by the rabbit gall-bladder

    DEFF Research Database (Denmark)

    Hansen, C P; Holstein-Rathlou, N H; Skøtt, O

    1991-01-01

    occurring at 50 mM Na+ were inhibited to the same degree by mucosal 1 mM amiloride. Substitution of 5-50 mM (44%) Na+ by Li+ in the external medium dose-dependently depressed Na+ absorption by up to 76%, while substitution by 50 mM choline had no significant effect. Li+ inhibition of Na+ absorption...

  16. Optimization of absorption air-conditioning for solar energy applications

    Science.gov (United States)

    Perry, E. H.

    1976-01-01

    Improved performance of solar cooling systems using the lithium bromide water absorption cycle is investigated. Included are computer simulations of a solar-cooled house, analyses and measurements of heat transfer rates in absorption system components, and design and fabrication of various system components. A survey of solar collector convection suppression methods is presented.

  17. GMRT Detection of HI 21cm Associated Absorption towards the ...

    Indian Academy of Sciences (India)

    Since the core is self-absorbed at this frequency, the absorption is most likely towards the hotspots. Comparison of the radio and deep optical images reveal linear filaments in the optical which overlap with the brighter radio jet towards the south-west.We therefore suggest that most of the HI 21 cm-line absorption could be ...

  18. In situ spectral aerosol absorption properties obtained in Valencia (Spain)

    Science.gov (United States)

    Segura, Sara; Estellés, Víctor; Esteve, Anna R.; Utrillas, María Pilar; Martínez-Lozano, José Antonio

    2014-05-01

    Aerosols play an important role in the radiative forcing in the Earth's atmosphere by scattering and absorbing solar radiation. Reducing uncertainties in the determination of aerosol light absorption is important in order to obtain better results for climate models. To do this, different methods and instruments are used to measure the absorption aerosol properties. The most common method for in-situ measurements is the filter-based technique, which determines the light absorption by measuring changes in the attenuation due by aerosols collected on a filter matrix. One of the instruments currently used for determining the absorption coefficient based on this technique is the Aethalometer (Magee Sci.). In this study, measurements have been obtained with a 7-wavelength Aethalometer AE-31 (Hansen et al., 1984). This instrument covers from the UV (370 nm) to the IR (950 nm) bands. As other filter-based instruments, the Aethalometer measurements also suffer artifacts which need to be compensated in order to determine the absorption coefficient (Weingartner et al., 2003). Specific site calibrated correction factors have been obtained for this site and applied to the data. Therefore, in - situ aerosol absorption properties at 7 different wavelengths have been obtained in Burjassot, Valencia, since 2011 in this study. Valencia is a medium size city in Spain (~1,800,000 inhabitants in the metropolitan area) located in the Western coast of the Mediterranean Sea. In total, a 3-year study of the absorption coefficient is presented attending to annual, seasonal and monthly variations. Spectral dependence of the aerosol absorption properties has been also analyzed using absorption coefficients obtained from the 7 Aethalometer channels. Determining the spectral dependence of aerosol absorption coefficient is important to distinguish different absorbing components. The major light-absorbing compounds among aerosols are carbonaceous substances and mineral dust. As the measurement

  19. An Empirical Investigation into a Subsidiary Absorptive Capacity Process Model

    DEFF Research Database (Denmark)

    Schleimer, Stephanie; Pedersen, Torben

    2011-01-01

    and empirically test a process model of absorptive capacity. The setting of our empirical study is 213 subsidiaries of multinational enterprises and the focus is on the capacity of these subsidiaries to successfully absorb best practices in marketing strategy from their headquarters. This setting allows us...... to explore the process model in its entirety, including different drivers of subsidiary absorptive capacity (organizational mechanisms and contextual drivers), the three original dimensions of absorptive capacity (recognition, assimilation, application), and related outcomes (implementation...... and internalization of the best practice). The study’s findings reveal that managers have discretion in promoting absorptive capacity through the application of specific organizational mechanism and that the impact of contextual drivers on subsidiary absorptive capacity is not direct, but mediated...

  20. Quantum of optical absorption in two-dimensional semiconductors.

    Science.gov (United States)

    Fang, Hui; Bechtel, Hans A; Plis, Elena; Martin, Michael C; Krishna, Sanjay; Yablonovitch, Eli; Javey, Ali

    2013-07-16

    The optical absorption properties of free-standing InAs nanomembranes of thicknesses ranging from 3 nm to 19 nm are investigated by Fourier transform infrared spectroscopy. Stepwise absorption at room temperature is observed, arising from the interband transitions between the subbands of 2D InAs nanomembranes. Interestingly, the absorptance associated with each step is measured to be ∼1.6%, independent of thickness of the membranes. The experimental results are consistent with the theoretically predicted absorptance quantum, AQ = πα/nc for each set of interband transitions in a 2D semiconductor, where α is the fine structure constant and nc is an optical local field correction factor. Absorptance quantization appears to be universal in 2D systems including III-V quantum wells and graphene.

  1. Effect of small ionospheric irregularities on radio wave absorption

    Science.gov (United States)

    Chen, H. C.; Fejer, J. A.

    1975-01-01

    The ionospheric absorption of a radio wave caused by small-scale irregularities with a gaussian autocorrelation function is calculated for various values of the linear scale height, the radio frequency, the scale size of the irregularities, and the mean-square fractional electron density fluctuations. The absorption is due to scattering of the radio wave into plasma oscillations by the irregularities. It is concluded that the absorption due to such irregularities with a mean-square fractional electron density deviation greater than about 0.000001 exceeds the normal collisional height-integrated absorption. Absorption of this type could play a significant part in heating experiments or in an ionosphere containing naturally occurring irregularities.

  2. Infrared absorption of human breast tissues in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Liu Chenglin [Department of Physics, Surface Physics Laboratory (National Key laboratory), Synchrotron Radiation Research Center, Fudan University, Shanghai 200433 (China); Physics Department of Yancheng Teachers' College, Yancheng 224002 (China); Zhang Yuan [Department of Physics, Surface Physics Laboratory (National Key laboratory), Synchrotron Radiation Research Center, Fudan University, Shanghai 200433 (China); Yan Xiaohui [Department of Physics, Surface Physics Laboratory (National Key laboratory), Synchrotron Radiation Research Center, Fudan University, Shanghai 200433 (China); Zhang Xinyi [Department of Physics, Surface Physics Laboratory (National Key laboratory), Synchrotron Radiation Research Center, Fudan University, Shanghai 200433 (China) and Shanghai Research Center of Acupuncture and Meridian, Pudong, Shanghai 201203 (China)]. E-mail: xy-zhang@fudan.edu.cn; Li Chengxiang [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China); Yang Wentao [Cancer Hospital, Medical Center, Fudan University, Shanghai 200032 (China); Shi Daren [Cancer Hospital, Medical Center, Fudan University, Shanghai 200032 (China)

    2006-07-15

    The spectral characteristics of human breast tissues in normal status and during different cancerous stages have been investigated by synchrotron radiation based Fourier transform infrared (SR-FTIR) absorption spectroscopy. Thanks to the excellent synchrotron radiation infrared (IR) source, higher resolving power is achieved in SR-FTIR absorption spectra than in conventional IR absorption measurements. Obvious variations in IR absorption spectrum of breast tissues were found as they change from healthy to diseased, or say in progression to cancer. On the other hand, some specific absorption peaks were found in breast cancer tissues by SR-FTIR spectroscopic methods. These spectral characteristics of breast tissue may help us in early diagnosis of breast cancer.

  3. Simulation of absorption refrigeration system for automobile application

    Directory of Open Access Journals (Sweden)

    Ramanathan Anand

    2008-01-01

    Full Text Available An automotive air-conditioning system based on absorption refrigeration cycle has been simulated. This waste heat driven vapor absorption refrigeration system is one alternate to the currently used vapour compression refrigeration system for automotive air-conditioning. Performance analysis of vapor absorption refrigeration system has been done by developing a steady-state simulation model to find the limitation of the proposed system. The water-lithium bromide pair is used as a working mixture for its favorable thermodynamic and transport properties compared to the conventional refrigerants utilized in vapor compression refrigeration applications. The pump power required for the proposed vapor absorption refrigeration system was found lesser than the power required to operate the compressor used in the conventional vapor compression refrigeration system. A possible arrangement of the absorption system for automobile application is proposed.

  4. Protein Hydrolysates as Promoters of Non-Haem Iron Absorption

    Directory of Open Access Journals (Sweden)

    Yanan Li

    2017-06-01

    Full Text Available Iron (Fe is an essential micronutrient for human growth and health. Organic iron is an excellent iron supplement due to its bioavailability. Both amino acids and peptides improve iron bioavailability and absorption and are therefore valuable components of iron supplements. This review focuses on protein hydrolysates as potential promoters of iron absorption. The ability of protein hydrolysates to chelate iron is thought to be a key attribute for the promotion of iron absorption. Iron-chelatable protein hydrolysates are categorized by their absorption forms: amino acids, di- and tri-peptides and polypeptides. Their structural characteristics, including their size and amino acid sequence, as well as the presence of special amino acids, influence their iron chelation abilities and bioavailabilities. Protein hydrolysates promote iron absorption by keeping iron soluble, reducing ferric iron to ferrous iron, and promoting transport across cell membranes into the gut. We also discuss the use and relative merits of protein hydrolysates as iron supplements.

  5. Exercise, Insulin Absorption Rates, and Artificial Pancreas Control

    Science.gov (United States)

    Frank, Spencer; Hinshaw, Ling; Basu, Rita; Basu, Ananda; Szeri, Andrew J.

    2016-11-01

    Type 1 Diabetes is characterized by an inability of a person to endogenously produce the hormone insulin. Because of this, insulin must be injected - usually subcutaneously. The size of the injected dose and the rate at which the dose reaches the circulatory system have a profound effect on the ability to control glucose excursions, and therefore control of diabetes. However, insulin absorption rates via subcutaneous injection are variable and depend on a number of factors including tissue perfusion, physical activity (vasodilation, increased capillary throughput), and other tissue geometric and physical properties. Exercise may also have a sizeable effect on the rate of insulin absorption, which can potentially lead to dangerous glucose levels. Insulin-dosing algorithms, as implemented in an artificial pancreas controller, should account accurately for absorption rate variability and exercise effects on insulin absorption. The aforementioned factors affecting insulin absorption will be discussed within the context of both fluid mechanics and data driven modeling approaches.

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

    Energy Technology Data Exchange (ETDEWEB)

    Abdelsalam, Hazem, E-mail: hazem.abdelsalam@etu.u-picardie.fr [Laboratory of Condensed Matter Physics, University of Picardie, Amiens 80039 (France); Department of Theoretical Physics, National Research Center, Cairo 12622 (Egypt); Talaat, Mohamed H. [Physics Department, Faculty of Science, Ain Shams University, Cairo (Egypt); Lukyanchuk, Igor [Laboratory of Condensed Matter Physics, University of Picardie, Amiens 80039 (France); L. D. Landau Institute for Theoretical Physics, Moscow (Russian Federation); Portnoi, M. E. [School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Saroka, V. A., E-mail: v.saroka@exeter.ac.uk [School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Institute for Nuclear Problems, Belarusian State University, Bobruiskaya 11, 220030 Minsk (Belarus)

    2016-07-07

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

  7. Luminal leptin inhibits intestinal sugar absorption in vivo.

    Science.gov (United States)

    Iñigo, C; Patel, N; Kellett, G L; Barber, A; Lostao, M P

    2007-08-01

    We have previously demonstrated that leptin inhibits galactose absorption in rat intestinal everted rings and that leptin receptors are present in the apical membrane of the enterocytes. This adipocyte-derived hormone is also secreted by gastric mucosal cells and is able to reach the intestinal lumen. The goal of the present study was to prove whether luminal leptin acts on intestinal sugar absorption in vivo both at low (basal state) and high sugar concentration (post-prandial state). In vivo intestinal sugar absorption in rat was measured with recirculating and single-pass perfusion systems. Sugar disappearance in the perfusate was measured by radioactivity and biochemical methods. Luminal leptin effect on intestinal absorption mediated by sodium-dependent glucose transporter 1 (SGLT1) and glucose transporter 2 (GLUT2) as well as intestinal permeability (mannitol absorption) was determined. Luminal leptin inhibited intestinal sugar absorption at low galactose concentrations, which indicates that leptin regulates SGLT1 activity in vivo. The inhibition was reversed in the absence of hormone in the intestinal lumen, suggesting that it was produced by post-translational regulation processes. At high luminal glucose concentrations, leptin also inhibited the phloretin-insensitive component of sugar absorption mediated by SGLT1. There was no significant effect on the apical GLUT2 component of absorption. Leptin did not modify in vivo intestinal permeability determined with (14)C-mannitol. These observations support the view that gastric leptin exerts a regulatory role on intestinal sugar absorption in the postprandial state by modifying the active component of absorption.

  8. EVIDENCE FOR PHOTOIONIZATION-DRIVEN BROAD ABSORPTION LINE VARIABILITY

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Tinggui; Yang, Chenwei; Wang, Huiyuan [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China); Ferland, Gary, E-mail: twang@ustc.edu.cn [Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506 (United States)

    2015-12-01

    We present a qualitative analysis of the variability of quasar broad absorption lines using the large multi-epoch spectroscopic data set of the Sloan Digital Sky Survey Data Release 10. We confirm that variations of absorption lines are highly coordinated among different components of the same ion or the same absorption component of different ions for C iv, Si iv, and N v. Furthermore, we show that the equivalent widths (EWs) of the lines decrease or increase statistically when the continuum brightens or dims. This is further supported by the synchronized variations of emission and absorption-line EWs when the well-established intrinsic Baldwin effect for emission lines is taken into account. We find that the emergence of an absorption component is usually accompanied by the dimming of the continuum while the disappearance of an absorption-line component is accompanied by the brightening of the continuum. This suggests that the emergence or disappearance of a C iv absorption component is only the extreme case, when the ionic column density is very sensitive to continuum variations or the continuum variability the amplitude is larger. These results support the idea that absorption-line variability is driven mainly by changes in the gas ionization in response to continuum variations, that the line-absorbing gas is highly ionized, and in some extreme cases, too highly ionized to be detected in UV absorption lines. Due to uncertainties in the spectroscopic flux calibration, we cannot quantify the fraction of quasars with asynchronized continuum and absorption-line variations.

  9. Digestion and absorption of olive oil

    Directory of Open Access Journals (Sweden)

    Muriana, Francisco J.G.

    2004-03-01

    Full Text Available Olive oil is a monounsaturated (oleic acid-rich fat, mainly constituted by triglycerides (>98 % and minor compounds. As other macronutrients, dietary triglyceride digestion and absorption are a complex processes involving enzyme activities and physicochemical changes. In humans, hydrolysis of olive oil triglycerides begins in the stomach where it is catalyzed by an acid-stable gastric lipase. Triglyceride hydrolysis continues in the duodenum, by the synergetic actions of gastric and colipase-dependent pancreatic lipases and bile secretion. Gastric lipolysis leads to the hydrolysis of 10-30 % of ingested triglycerides, generating mainly diglycerides (DG and free fatty acids. This facilitates subsequent triglyceride hydrolysis by pancreatic lipase by allowing fat emulsification. Pancreatic lipase cleaves the sn-1 and sn-3 positions of triglycerides and/or DG obtaining sn-2 monoglycerides. Different lipid metabolites are quickly absorbed along the epithelial cells of the small intestine, acting olive oil as a supplier of oleic-acid-rich hydrocarbon skeletons for cellular synthesis of triglycerides and phospholipids. Absorption of mostly minor compounds of (extra virgin olive oil takes place in the small intestine, as native or derivatives. Compared to diets rich in polyunsaturated fatty acids, olive oil suppresses gastric acid secretion and is a potent releasing factor of cholecystokinin peptide, which consistently indicate that the consumption of olive oil might be beneficial in digestive diseases.El aceite de oliva es una grasa monoinsaturada (rica en ácido oleico, compuesta por triglicéridos (>98% y componentes menores. En los procesos de digestión y absorción de los triglicéridos participan enzimas y se producen cambios fisicoquímicos. La lipasa gástrica es el componente mayoritario de la actividad lipolítica gástrica en humanos. La hidrólisis de los triglicéridos continúa en el duodeno, por la acción sinérgica de las lipasas g

  10. Design for Manufacturing for Energy Absorption Systems

    Science.gov (United States)

    Del Prete, A.; Primo, T.; Papadia, G.; Manisi, B.

    2011-05-01

    In the typical scenario of a helicopter crash, impact with the ground is preceded by a substantially vertical drop, with the result that a seated occupant of a helicopter experiences high spinal loads and pelvic deceleration during such crash due to the sudden arresting of vertical downward motion. It has long been recognized that spinal injuries to occupants of helicopters in such crash scenario can be minimized by seat arrangements which limit the deceleration to which the seated occupant is subjected, relative to the helicopter, to a predetermined maximum, by allowing downward movement of the seated occupant relative to the helicopter, at the time of impact with the ground, under a restraining force which, over a limited range of such movement, is limited to a predetermined maximum. In practice, significant benefits, in the way of reduced injuries and reduced seriousness of injuries, can be afforded in this way in such crash situations even where the extent of such controlled vertical movement permitted by the crashworthy seat arrangement is quite limited. Important increase of accident safety is reached with the installation of crashworthy shock absorbers on the main landing gear, but this solution is mostly feasible on military helicopters with long fixed landing gear. Seats can then give high contribution to survivability. Commonly, an energy absorber is a constant load device, if one excludes an initial elastic part of the load-stroke curve. On helicopter seats, this behavior is obtained by plastic deformation of a metal component or scraping of material. In the present work the authors have studied three absorption systems, which differ in relation to their shape, their working conditions and their constructive materials. All the combinations have been analyzed for applications in VIP helicopter seats.

  11. New in vitro dermal absorption database and the prediction of dermal absorption under finite conditions for risk assessment purposes

    NARCIS (Netherlands)

    Buist, H.E.; Burgsteden, J.A. van; Freidig, A.P.; Maas, W.J.M.; Sandt, J.J.M. van de

    2010-01-01

    Most QSARs for dermal absorption predict the permeability coefficient, Kp, of a molecule, which is valid for infinite dose conditions. In practice, dermal exposure mostly occurs under finite dose conditions. Therefore, a simple model to predict finite dose dermal absorption from infinite

  12. New in vitro dermal absorption database and the prediction of dermal absorption under finite conditions for risk assessment purposes.

    NARCIS (Netherlands)

    Buist, H.E.; Burgsteden, J.A. van; Freidig, A.P.; Maas, W.J.; Sandt, J.J. van de

    2010-01-01

    Most QSARs for dermal absorption predict the permeability coefficient, K(p), of a molecule, which is valid for infinite dose conditions. In practice, dermal exposure mostly occurs under finite dose conditions. Therefore, a simple model to predict finite dose dermal absorption from infinite dose data

  13. Broadband reflectionless metamaterials with customizable absorption-transmission-integrated performance

    Science.gov (United States)

    Shen, Yang; Zhang, Jieqiu; Pang, Yongqiang; Li, Yongfeng; Zheng, QiQi; Wang, Jiafu; Ma, Hua; Qu, Shaobo

    2017-08-01

    Broadband reflectionless metamaterials with customizable absorption-transmission-integrated performance are proposed, discussed, and demonstrated in this paper. The three-dimensional metamaterial absorbers (MAs) consist of multilayered metal-insulator composition which are introduced here for broadband electromagnetic wave absorption. The frequency selective surfaces (FSSs) backed on the bottom also help achieve multi-transmissions inside or outside of the absorption band. Simulations indicate that diversiform combinations of the MAs and the FSSs will contribute more choice of customizable absorption-transmission-integrated performance. Compared with the foregoing designs, the three-dimensional MAs used here possess broadband absorption with abrupt transition zone which are easier to achieve absorption-transmission-integrated performance with almost no reflection during the entire frequency band. Meanwhile, the simple component and the easy fabrication also make it possible for the absorption-transmission-integrated metamaterials (ATMAs) to be referenced at higher frequencies, such as infrared or optical frequencies. At last, an experimental proof is given at the microwave frequencies. The good agreement between simulation and measurement indicates that our proposed ATMAs will exhibit great potential applications, for example, stealth technology, communication security, and selective multi-frequency sensing.

  14. Analysis of in-situ spectral absorption meter data

    Science.gov (United States)

    Zaneveld, J. Ronald V.; Kitchen, James C.; Bricaud, Annick; Moore, Casey C.

    1992-12-01

    In situ absorption data collected with a reflective-tube absorption meter are presented. Various procedures for correcting the data for scattering error and for extracting chlorophyll absorption from the raw signal are explored. Based on our knowledge of the distribution of particle types and on measured backscattering, the scattering correction as a function of total scattering is found to vary significantly with depth. However, absorption in the near infrared is shown to be highly correlated with backscattering. We thus postulate that this signal is mainly due to the scattering error and possibly to absorption by dissolved substances and particles of a detrital nature. Thus, the infrared signal seems to provide a good correction for the measured a(676) to obtain chloropigment absorption. Indeed, a(676) - a(750) (corrected for water absorption and 750 temperature dependence) was found to correlate strongly with fluorescence. However, a(750) was found to be highly temperature dependent, so a(712) was chosen for this purpose in future measurements. An examination of optical microstructure in East Sound, Orcas Island, Washington showed numerous peaks with vertical dimensions of the order of tens of centimeters. These peaks may contain the majority of the biomass in the system. The relative magnitude of the a(676) - a(712) and the a(712) signals varied greatly from one peak to another and systematically with depth, presumably reflecting the nature and physiological states of the populations in the various peaks.

  15. Acoustic absorption behaviour of an open-celled aluminium foam

    CERN Document Server

    Han Fu Sheng; Zhao Yu Yuan; Gibbs, B

    2003-01-01

    Metal foams, especially close-celled foams, are generally regarded as poor sound absorbers. This paper studies the sound absorption behaviour of the open-celled Al foams manufactured by the infiltration process, and the mechanisms involved. The foams show a significant improvement in sound absorption compared with close-celled Al foams, because of their high flow resistance. The absorption performance can be further enhanced, especially at low frequencies, if the foam panel is backed by an appropriate air gap. Increasing the air-gap depth usually increases both the height and the width of the absorption peak and shifts the peak towards lower frequencies. The foam samples with the smallest pore size exhibit the best absorption capacities when there is no air gap, whereas those with medium pore sizes have the best overall performance when there is an air gap. The typical maximum absorption coefficient, noise reduction coefficient and half-width of the absorption peak are 0.96-0.99, 0.44-0.62 and 1500-3500 Hz, r...

  16. Harnessing the electromagnetic absorptions of metamaterials for positive applications

    Science.gov (United States)

    Xiang, Yuanjiang; Zou, Yanhong; Luo, Hailu; Dai, Xiaoyu; Wen, Shuangchun; Fan, Dianyuan

    2010-08-01

    Absorption or loss is inevitable for the metal-based metamaterials (MMs) due to the intrinsic loss of the metal, and constitutes a major hurdle to the practical realization of most applications such as a sub-wavelength lens. Thus, to reduce the losses becomes one of the major challenges in the MM field. However, the inevitable loss can also be harnessed to take a positive role in the applications of MMs such as stealth technology or other types of cloaking devices. In this presentation, after a brief review of the advances in MMs-based absorbers, we present several schemes to fulfill the desired electromagnetic absorption properties, both linear and nonlinear. For linear absorption, we have experimentally demonstrated that the absorption performance of an ordinary microwave absorbing material can be evidently improved by using the electric resonance resulting from an array of subwavelength metallic circuit elements. For nonlinear absorption, we show theoretically that the active linear magnetic permeability induces a nonlinear absorption, similar to the two-photon absorption (TPA), of electric field in a lossy MM with a Kerr-type nonlinear polarization.

  17. Absorption sites of orally administered drugs in the small intestine.

    Science.gov (United States)

    Murakami, Teruo

    2017-12-01

    In pharmacotherapy, drugs are mostly taken orally to be absorbed systemically from the small intestine, and some drugs are known to have preferential absorption sites in the small intestine. It would therefore be valuable to know the absorption sites of orally administered drugs and the influencing factors. Areas covered:In this review, the author summarizes the reported absorption sites of orally administered drugs, as well as, influencing factors and experimental techniques. Information on the main absorption sites and influencing factors can help to develop ideal drug delivery systems and more effective pharmacotherapies. Expert opinion: Various factors including: the solubility, lipophilicity, luminal concentration, pKa value, transporter substrate specificity, transporter expression, luminal fluid pH, gastrointestinal transit time, and intestinal metabolism determine the site-dependent intestinal absorption. However, most of the dissolved fraction of orally administered drugs including substrates for ABC and SLC transporters, except for some weakly basic drugs with higher pKa values, are considered to be absorbed sequentially from the proximal small intestine. Securing the solubility and stability of drugs prior to reaching to the main absorption sites and appropriate delivery rates of drugs at absorption sites are important goals for achieving effective pharmacotherapy.

  18. Nebular Hydrogen Absorption in the Ejecta of Eta Carinae

    Science.gov (United States)

    Gull, Theodore R.; Ishibashi, K.; Davidson, K.; Fisher, Richard R. (Technical Monitor)

    2000-01-01

    Space Telescope Imaging Spectrograph (STIS) observations of Eta Carinae and immediate ejecta reveal narrow Balmer absorption lines in addition to the nebular-scattered broad P-Cygni absorptions. The narrow absorption correlates with apparent disk structure that separates the two Homunculus lobes. We trace these features about half way up the Northern lobe until the scattered stellar Balmer line doppler-shifts redward beyond the nebular absorption feature. Three-dimensional data cubes, made by mapping the Homunculus at Balmer alpha and Balmer beta with the 52 x 0.1 arcsecond aperture and about 5000 spectral resolving power, demonstrate that the absorption feature changes slowly in velocity with nebular position. We have monitored the stellar Balmer alpha line profile of the central source over the past four years. The equivalent width of the nebular absorption feature changes considerably between observations. The changes do not correlate with measured brightness of Eta Carinae. Likely clumps of neutral hydrogen with a scale size comparable to the stellar disk diameter are passing through the intervening light path on the timescales less than several months. The excitation mechanism involves Lyman alpha radiation (possibly the Lyman series plus Lyman continuum) and collisions leading to populating the 2S metastable state. Before the electron can jump to the ground state by two photon emission (lifetime about 1/8 second), a stellar Balmer photon is absorbed and the electron shifts to an NP level. We see the absorption feature in higher Balmer lines, and but not in Paschen lines. Indeed we see narrow nebular Paschen emission lines. At present, we do not completely understand the details of the absorption. Better understanding should lead to improved insight of the unique conditions around Eta Carinae that leads to these absorptions.

  19. [Light absorption by suspended particulate matter in Chagan Lake, Jilin].

    Science.gov (United States)

    Wang, Yuan-Dong; Liu, Dian-Wei; Song, Kai-Shan; Zhang, Bai; Wang, Zong-Ming; Jiang, Guang-Ji; Tang, Xu-Guang; Lei, Xiao-Chun; Wu, Yan-Qing

    2011-01-01

    Spectral characteristics and the magnitudes of light absorption by suspended particulate matter were determined by spectrophotometry in this optically complex Lake Chagan waters for the purpose of surveying the natural variability of the absorption coefficients to parameterize the bio-optical models for converting satellite or in-situ water reflectance signatures into water quality information. Experiments were carried out on seasonal frozen Lake Chagan, one representative inland case-2 water body in Northeast of China. Particulate absorption properties analyzed using the field data on July 15th and October 12th 2009 were measured using the quantitative filter technique to produce absorption spectra containing several fractions that could be attributed to two main optical active constituents (OACs) phytoplankton pigments and non-algal particulates (mineral sediments, and organic detritus). Results suggested that the suspended particulate matter (SPM) concentration was higher while phytoplankton biomass (chlorophyll-a concentration) was lower in July and that in October. The spectral shape of total suspended particulate matter resembled that of non-algal particulates which contributed greater than phytoplankton in total particulate absorption during both periods. An obvious absorption peak occurring at around 440 nm exhibited an increase in phytoplankton contribution in October. Non-algal particulate absorption at 440 nm (a(NAP) (440)) had better correlation with total suspended particulate matter concentration than that with chlorophyll-a over the two periods. Light absorption by phytoplankton pigments in the Chagan lake region was generally lower than that of non-algal components. Chl. a dominating phytoplankton pigment composition functioned exponentially with its absorption coefficients at 440 and 675 nm specifically, the average values of which in July were 0.146 8 m2 x mg(-1) and 0.050 3 respectively while in October they were 0.153 3 and 0.013 2 m2 x mg(-1

  20. The Role of Absorption Cooling for Reaching Sustainable Energy Systems

    Energy Technology Data Exchange (ETDEWEB)

    Lindmark, Susanne

    2005-07-01

    This thesis focuses on the role and potential of absorption cooling in future energy systems. Two types of energy systems are investigated: a district energy system based on waste incineration and a distributed energy system with natural gas as fuel. In both cases, low temperature waste heat is used as driving energy for the absorption cooling. The main focus is to evaluate the absorption technology in an environmental perspective, in terms of reduced CO{sub 2} emissions. Economic evaluations are also performed. The reduced electricity when using absorption cooling instead of compression cooling is quantified and expressed as an increased net electrical yield. The results show that absorption cooling is an environmentally friendly way to produce cooling as it reduces the use of electrically driven cooling in the energy system and therefore also reduces global CO{sub 2} emissions. In the small-scale trigeneration system the electricity use is lowered with 84 % as compared to cooling production with compression chillers only. The CO{sub 2} emissions can be lowered to 45 CO{sub 2}/MWh{sub c} by using recoverable waste heat as driving heat for absorption chillers. However, the most cost effective cooling solution in a district energy system is a combination between absorption and compression cooling technologies according to the study. Absorption chillers have the potential to be suitable bottoming cycles for power production in distributed systems. Net electrical yields over 55 % may be reached in some cases with gas motors and absorption chillers. This small-scale system for cogeneration of power and cooling shows electrical efficiencies comparable to large-scale power plants and may contribute to reducing peak electricity demand associated with the cooling demand.

  1. Molecular shock response of explosives: electronic absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mcgrne, Shawn D [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory; Whitley, Von H [Los Alamos National Laboratory; Bolme, Cindy A [Los Alamos National Laboratory; Eakins, Daniel E [Los Alamos National Laboratory

    2009-01-01

    Electronic absorption spectroscopy in the range 400-800 nm was coupled to ultrafast laser generated shocks to begin addressing the question of the extent to which electronic excitations are involved in shock induced reactions. Data are presented on shocked polymethylmethacrylate (PMMA) thin films and single crystal pentaerythritol tetranitrate (PETN). Shocked PMMA exhibited thin film interference effects from the shock front. Shocked PETN exhibited interference from the shock front as well as broadband increased absorption. Relation to shock initiation hypotheses and the need for time dependent absorption data (future experiments) is briefly discussed.

  2. Scheme for achieving coherent perfect absorption by anisotropic metamaterials

    KAUST Repository

    Zhang, Xiujuan

    2017-02-22

    We propose a unified scheme to achieve coherent perfect absorption of electromagnetic waves by anisotropic metamaterials. The scheme describes the condition on perfect absorption and offers an inverse design route based on effective medium theory in conjunction with retrieval method to determine practical metamaterial absorbers. The scheme is scalable to frequencies and applicable to various incident angles. Numerical simulations show that perfect absorption is achieved in the designed absorbers over a wide range of incident angles, verifying the scheme. By integrating these absorbers, we further propose an absorber to absorb energy from two coherent point sources.

  3. Sensitivity of the CCM climate to enhanced cloud absorption

    Energy Technology Data Exchange (ETDEWEB)

    Kiehl, J. [National Center for Atmospheric Research (NCAR), Boulder, CO (United States)

    1995-09-01

    Recent indications suggest that clouds may be absorbing more solar radiation than was previously thought. This research investigates some of the evidence for this hypothesis; potential physical mechanisms are briefly discussed as well. The climatic implications of the enhanced absorption are investigated using the NCAR Community Climate Model (CCM). It is found that the model`s heat budget in the tropical warm pool agrees more closely with observations when enhanced absorption is included. On the whole, the addition of enhanced absorption improves the model`s performance in the tropics and degrades it in the extra-tropics. 3 figs.

  4. Aerosol Absorption Near Beijing During EAST-AIRE

    Science.gov (United States)

    Yang, M.; Howell, S.; Huebert, B.; Zhuang, J.

    2006-12-01

    To understand the aerosol absorption that had been observed offshore during ACE-Asia, we took a suite of instruments (including a 7 wavelength aethalometer) to a site 70 km ESE of Beijing in March of 2005 to measure the wavelength dependence of aerosol absorption as a part of the EAST-AIRE program. Confidence in filter methods suffers a bit because several corrections are required to estimate ambient absorption from particles on a filter: there is enhancement by multiple scatter from the filter's matrix, shadowing by thick cakes of collected particles, and scattering by co-collected aerosols, to name a few. We encountered mild dust, heavy pollution, relatively clean air, coal-burning chimney plumes, industrial plumes, and biomass burning, often at separate times. The absorption Angstrom exponent was always greater than 1, averaging 1.5: in the UV and violet there is an enhanced absorption over what one would expect of black carbon. If we assume that BC is responsible for all the absorption at 950 nm and that it has an Angstrom coefficient of 1.0 (yielding a specific absorbance of about 9 m2g-1 at 550 nm), the remaining absorption Angstrom exponent in the visible averaged 3.2. However, the 370-950 nm absorption spectrum of the remainder looked very much like the clay and hematite absorption spectra published by Sokolik and Toon, including a striking UV absorption and a characteristic dip around 660 nm (e.g., not a power law shape). This is not surprising, since clay is both a frequent component of dust and is used as a binder in the charcoal briquettes that are widely used in China for heating and cooking. We found single-scatter albedos virtually always less than 0.9, averaging 0.82. In the presence of dust, the SSA increased toward the IR. We also find that the clay spectrum explains virtually all the non-BC absorption, so there must not be much brown carbon present. Our confidence in these on-filter absorption measurements is increased by the fact that we

  5. In vivo and In vitro Evaluations of Intestinal Gabapentin Absorption

    DEFF Research Database (Denmark)

    Larsen, Malte Selch; Frølund, Sidsel; Nøhr, Martha Kampp

    2015-01-01

    cells. The effect of co-application of the LAT-inhibitor, BCH, and the b(0,+)-substrate, L-lysine, on intestinal transport of gabapentin was evaluated in vivo and in vitro. RESULTS: Gabapentin showed dose-dependent oral absorption kinetics and dose-independent disposition kinetics. Co-application of BCH...... inhibited intestinal absorption in vivo and apical uptake in vitro, whereas no effect was observed following co-application of L-lysine. CONCLUSIONS: The present study shows for the first time that BCH was capable of inhibiting intestinal absorption of gabapentin in vivo. Furthermore, in Caco-2 cell...

  6. Tunable large resonant absorption in a midinfrared graphene Salisbury screen

    Science.gov (United States)

    Jang, Min Seok; Brar, Victor W.; Sherrott, Michelle C.; Lopez, Josue J.; Kim, Laura; Kim, Seyoon; Choi, Mansoo; Atwater, Harry A.

    2014-10-01

    The optical absorption properties of periodically patterned graphene plasmonic resonators are studied experimentally as the graphene sheet is placed near a metallic reflector. By varying the size and carrier density of the graphene, the parameters for achieving a surface impedance closely matched to free-space (Z0=377Ω) are determined and shown to result in 24.5% total optical absorption in the graphene sheet. Theoretical analysis shows that complete absorption is achievable with higher doping or lower loss. This geometry, known as a Salisbury screen, provides an efficient means of light coupling to the highly confined graphene plasmonic modes for future optoelectronic applications.

  7. Systemic absorption of insulin from a Gelfoam ocular device.

    Science.gov (United States)

    Lee, Y; Yalkowsky, S H

    1999-11-10

    In previous reports (Lee et al., 1997b; Lee and Yalkowsky, 1999), it has been shown that insulin, delivered by an acidified Gelfoam (absorbable gelatin sponge, USP) based ocular device, can be efficiently absorbed into the systemic circulation without the aid of an absorption enhancer. The role of acid in the enhancer-free absorption of insulin is investigated in this report. Gelfoam ocular devices containing 0.2 mg of sodium insulin prepared with either water or 10% acetic acid were evaluated in rabbits. The results suggest that a change in the Gelfoam upon treatment with acid is responsible for the efficient systemic absorption of insulin from these enhancer-free devices.

  8. Seasonal changes in lead absorption in laboratory rats.

    OpenAIRE

    Barton, J.C.; Huster, W J

    1987-01-01

    A retrospective study of the relationship of season to the absorption of radiolead in laboratory rats was performed using data representing 305 animals from 36 experiments over 6 calendar years. Male Wistar rats weighing 200 to 250 g were given 1 microgram of radiolabeled lead in an aqueous solution, pH 4.0, in isolated small intestine, and absorption of the radiolead was quantified after a 4-hour interval using whole-body counting. Similar values of absorption occurred in the summer (June-Au...

  9. Impact, absorption and evaporation of raindrops on building facades

    DEFF Research Database (Denmark)

    Abuku, Masaru; Janssen, Hans; Poesen, Jean

    2009-01-01

    . Finally, the experimental and numerical data were used in a more precise three-dimensional simulation of impact, absorption and evaporation of random and discrete wind-driven raindrops. This was compared With the common one-dimensional simulation of absorption and evaporation at the facade considering......In this paper, the impact, absorption and evaporation of raindrops oil building facades is investigated by experimental and numerical means. Laboratory experiments were carried Out to study the impact of water drops with different diameters, impact speeds and impact angles oil a porous building...

  10. Laser calorimeter for UV absorption measurement of dielectric thin films.

    Science.gov (United States)

    Sahoo, N K; Apparao, K V

    1992-10-01

    We describe a dual-technique laser calorimeter for measuring the absorption of dielectric thin films in the UV region below 400 nm. The instrument measures the temperature rise and absorption of a sample simultaneously by two independent techniques, namely, a resistance thermometer and a temperature transducer. The absorption constant beta and extinction coefficient kappa of Sb(2)O(3) and ZrO(2) films at 308 and 337 nm are measured by using the calorimeter. The principle, construction, and application of the calorimeter are described.

  11. Understanding Absorptive Capacities is an "Innovation Systems" Context

    DEFF Research Database (Denmark)

    Narula, Rajneesh

    2004-01-01

    , employment creation and their interrelations. We then analyse the elementsof absorptive capability, focusing on the nature of the relationship within a systems view of aneconomy, focusing primarily on the role of firm and non-firm actors and the institutions thatconnect them, both within and across borders....... We also undertake to explain how the nature ofabsorptive capacity changes with stages of economic development, and the importance of thedifferent aspects of absorptive capability at different stages. The relationship is not a linear one:the benefits that accrue from marginal increases in absorptive...

  12. Steam Driven Triple Effect Absorption Solar Cooling System

    OpenAIRE

    Yabase, Hajime; Makita, Kazuyuki

    2012-01-01

    The authors propose a solar cooling system employing a steam-driven triple effect absorption chiller as a new technique for saving CO2 emission in the air conditioning field. The absorption chiller is a cooling machine using thermal energy as a drive source, and it is ideal for utilizing solar heat. In addition, by employing a triple effect absorption chiller of high efficiency, a high energy saving effect and a significant CO2 saving effect can be expected. As a result of studies, it has bee...

  13. Glucose Absorption by the Bacillary Band of Trichuris muris

    DEFF Research Database (Denmark)

    Hansen, Tina Vicky Alstrup; Hansen, Michael; Nejsum, Peter

    2016-01-01

    of the bacillary band in living worms was explored using a fluorescent glucose analogue (6-NBDG) and confocal microscopy. To study the absorptive function of the bacillary band in relation to 6-NBDG, the oral uptake was minimised or excluded by sealing the oral cavity with glue and agarose. Principal Findings....... Conclusions/Significance Trichuris muris is dependent on glucose for viability in vitro, and the bacillary band has an absorptive function in relation to 6-NBDG, which accumulates within the stichocytes. The absorptive function of the bacillary band calls for an exploration of its possible role in the uptake...

  14. Anisotropy of infrared absorption in (110) porous silicon layers

    Energy Technology Data Exchange (ETDEWEB)

    Timoshenko, V. Yu.; Osminkina, L.A.; Efimova, A.I.; Fomenko, M.A.; Golovan, L.A.; Kashkarov, P.K. [Moscow State M. V. Lomonosov University, Physics Department, 119992 Moscow (Russian Federation); Kovalev, D.; Kuenzner, N.; Gross, E.; Diener, J.; Koch, F. [Technische Universitaet Muenchen, Physik-Department E16, 85747 Garching (Germany)

    2005-06-01

    In-plane birefringent porous Si (PSi) layers formed from heavily boron-doped (110)Si wafers are investigated by using polarization-resolved infrared absorption (IR) spectroscopy. The absorption by free charge carriers and by Si-H{sub x} (x=1,2,3) surface bond vibrations are found to exhibit strong anisotropy (dichroism), which originates from the form anisotropy of Si nanocrystals assembling (110)PSi layers. The free carrier absorption dichroism is explained by using the effective medium approximation and classical Drude model and considering additional carrier scattering in anisotropically shaped Si nanocrystals. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  15. Self-Affine Graphene Metasurfaces for Tunable Broadband Absorption

    Science.gov (United States)

    Wu, Pin Chieh; Papasimakis, Nikitas; Tsai, Din Ping

    2016-10-01

    Graphene has emerged as a promising platform for THz metasurfaces supporting electrically tunable deep-subwavelength plasmonic excitations. Here, we introduce a broadband graphene metasurface based on the Hilbert curve, a continuous, space-filling fractal. We demonstrate the enhancement of graphene absorption over a broad frequency band (0.5-60 THz) with an average absorption level exceeding 20%. Owing to the continuous nature of the metasurface patterns, both the absorption level and the bandwidth can be controlled electrically by varying the graphene charge-carrier concentration.

  16. Measurements of the Absorptive Properties of the Ionosphere

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Absorption of radio waves occurs when electrons responding to the wave fields collide with and transfer energy to the neutral particles. A study of ionospheric...

  17. Effect of applied mechanical stress on absorption coefficient of compounds

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Manoj Kumar, E-mail: mkgupta.sliet@gmail.com [Department of Applied Sciences, Bhai Gurdas Institute of Engineering and Technology, Sangrur (India); Singh, Gurinderjeet; Dhaliwal, A. S.; Kahlon, K. S. [Department of Physics, Sant Longowal Institute of Engineering & Technology Deemed University, Longowal (Sangrur) India-148106 (India)

    2015-08-28

    The absorption coefficient of given materials is the parameter required for the basic information. The measurement of absorption coefficient of compounds Al{sub 2}O{sub 3}, CaCO{sub 3}, ZnO{sub 2}, SmO{sub 2} and PbO has been taken at different incident photon energies 26, 59.54, 112, 1173, 1332keV. The studies involve the measurements of absorption coefficient of the self supporting samples prepared under different mechanical stress. This mechanical stress is render in terms of pressure up to 0-6 ton by using hydraulic press. Measurements shows that absorption coefficient of a material is directly proportional to applied mechanical stress on it up to some extent then become independent. Experimentally measured results are in fairly good agreement with in theoretical values obtained from WinXCOM.

  18. Using lamb waves tomonitor moisture absorption thermally fatigues composite laminates

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Sun; Cho, Youn Ho [School of Mechanical Engineering, Pusan National University, Busan (Korea, Republic of)

    2016-06-15

    Nondestructive evaluation for material health monitoring is important in aerospace industries. Composite laminates are exposed to heat cyclic loading and humid environment depending on flight conditions. Cyclic heat loading and moisture absorption may lead to material degradation such as matrix breaking, debonding, and delamination. In this paper, the moisture absorption ratio was investigated by measuring the Lamb wave velocity. The composite laminates were manufactured and subjected to different thermal aging cycles and moisture absorption. For various conditions of these cycles, not only changes in weight and also ultrasonic wave velocity were measured, and the Lamb wave velocity at various levels of moisture on a carbon-epoxy plate was investigated. Results from the experiment show a linear correlation between moisture absorption ratio and Lamb wave velocity at different thermal fatigue stages. The presented method can be applied as an alternative solution in the online monitoring of composite laminate moisture levels in commercial flights.

  19. Identification of Metal Absorption Lines on Quasar Spectra of SDSS ...

    Indian Academy of Sciences (India)

    . Baise 533000, China. 2Guangdong University of Technology, Guangzhou 510006, China. 3Centre for Astrophysics, Guangzhou University, Guangzhou 510006, China. ∗ e-mail: cysu@gdut.edu.cn. Abstract. Absorption lines are an important ...

  20. Optical Salisbury screen with design-tunable resonant absorption bands

    Science.gov (United States)

    Nath, Janardan; Smith, Evan; Maukonen, Douglas; Peale, Robert E.

    2014-05-01

    A thin-film selective absorber at visible and near infra-red wavelengths is demonstrated. The structure consists of an optically thick layer of gold, a SiO2 dielectric spacer and a partially transparent gold film on top. The optical cavity so formed traps and absorbs light at a resonance wavelength determined by the film thicknesses. Observed fundamental-resonance absorption strengths are in the range 93%-97%. The absorption red-shifts and broadens as the thickness of the top gold layer is decreased with little change in absorption strength. Thus, strong absorption with design-tunable wavelength and width is achieved easily by unstructured blanket depositions. Observed angle-dependent spectra agree well with the recent three-layer analytical model of Shu et al. [Opt. Express 21, 25307 (2013)], if effective medium approximation is used to calculate the permittivity of the top gold film when it becomes discontinuous at the lowest thicknesses.

  1. Enhanced universal absorption of graphene in a Salisbury screen

    Science.gov (United States)

    Ying, Xiangxiao; Pu, Yang; Luo, Yi; Peng, Hao; Li, Zhe; Jiang, Yadong; Xu, Jimmy; Liu, Zhijun

    2017-01-01

    As an emerging optoelectronic material, graphene's universal absorption of about 2.3% over a broad frequency range from infrared to visible, as determined by its interband transition, presents both a new opportunity and a limitation. Here we report on a multifold enhancement of the absorption using a simple strategy, often referred to as the Salisbury screen. It consists of a graphene sheet on top of a SiO2 dielectric layer backed with a copper metallic reflector. For a monolayer graphene, peak absorptions of 9% at near normal incidence and 40% at near grazing angle are experimentally demonstrated in the near-infrared region, in good agreement with calculations using transfer matrix method. The resultant absorption enhancement suggests a great potential for graphene to be used in infrared optoelectronic components.

  2. Infrared differential absorption lidar for stand-off detection of ...

    Indian Academy of Sciences (India)

    2014-02-14

    ) carbon dioxide laser-based differential absorption lidar (DIAL) system capable of stand-off detection of chemical clouds in aerosol and vapour form upto about 200 m range in the atmosphere has been developed and ...

  3. Measurements of scattering and absorption in mammalian cell suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Mourant, J.R.; Johnson, T.M.; Freyer, J.P.

    1996-03-01

    During the past several years a range of spectroscopies, including fluorescence and elastic-scatter spectroscopy, have been investigated for optically based detection of cancer and other tissue pathologies. Both elastic-scatter and fluorescence signals depend, in part, on scattering and absorption properties of the cells in the tissue. Therefore an understanding of the scattering and absorption properties of cells is a necessary prerequisite for understanding and developing these techniques. Cell suspensions provide a simple model with which to begin studying the absorption and scattering properties of cells. In this study we have made preliminary measurements of the scattering and absorption properties of suspensions of mouse mammary carcinoma cells (EMT6) over a broad wavelength range (380 nm to 800 nm).

  4. Moisture Absorption Model of Composites Considering Water Temperature Effect

    Directory of Open Access Journals (Sweden)

    HUI Li

    2016-11-01

    Full Text Available The influence of water temperature on composite moisture absorption parameters was investigated in temperature-controlled water bath. Experiments of carbon fiber/bismaleimide resin composites immersed in water of 60℃, 70℃and 80℃ were developed respectively. According to the moisture content-time curves obtained from the experimental results, the diffusion coefficient and the balanced moisture content of the composites immersed in different water temperature could be calculated. What's more, the effect of water temperature on the diffusion coefficient and the balanced moisture content were discussed too. According to the Arrhenius equation and the law of Fick, a moisture absorption model was proposed to simulate the hygroscopic behaviour of the composite laminates immersed in different water temperature which can predict the absorption rate of water of the composites immersed in distilled water of 95℃ at any time precisely and can calculate how long it will take to reach the specific absorption rate.

  5. 14 CFR 25.723 - Shock absorption tests.

    Science.gov (United States)

    2010-01-01

    ... absorption tests. (a) The analytical representation of the landing gear dynamic characteristics that is used... previously approved design weights and minor changes in design may be substantiated by analyses based on...

  6. [Physiology of intestinal absorption of phosphorus in animals].

    Science.gov (United States)

    Barlet, J P; Davicco, M J; Coxam, V

    1995-01-01

    Intestinal absorption of inorganic phosphorus. In most mammalian species inorganic phosphorus (P) is absorbed at the duodenal and jejunal level. However in horses some P is absorbed from the large intestine, whereas in ruminant animals some absorption also takes place in the forestomachs. The structure of the putative phosphate-sodium carrier of the brush border from enterocytes still awaits identification. P absorption is modulated both by endocrine (calcitriol, triiodothyronine) and nutritional factors (minerals of the diet, chemical form of phosphorus). Regulation of salivary P secretion, intestinal absorption of P in ruminants, and its adaptation to diets high or low in P are still poorly understood. Such studies would probably help to decrease the cost of P supplementation in farm animals.

  7. Measurements of scattering and absorption in mammalian cell suspensions

    Science.gov (United States)

    Mourant, Judith R.; Freyer, James P.; Johnson, Tamara M.

    1996-04-01

    During the past several years a range of spectroscopies, including fluorescence and elastic- scatter spectroscopy, have been investigated for optically based detection of cancer and other tissue pathologies. Both elastic-scatter and fluorescence signals depend, in part, on scattering and absorption properties of the cells in the tissue. Therefore an understanding of the scattering and absorption properties of cells is a necessary prerequisite for understanding and developing these techniques. Cell suspensions provide a simple model with which to begin studying the absorption and scattering properties of cells. In this study we have made preliminary measurements of the scattering and absorption properties of suspensions of mouse mammary carcinoma cells (EMT6) over a broad wavelength range (380 nm to 800 nm).

  8. Demonstrating an absolute quantum advantage in direct absorption measurement

    National Research Council Canada - National Science Library

    Paul-Antoine Moreau; Javier Sabines-Chesterking; Rebecca Whittaker; Siddarth K Joshi; Patrick M Birchall; Alex McMillan; John G Rarity; Jonathan C F Matthews

    2017-01-01

    ... strategies can be improved. Here, for optical direct absorption measurement, we experimentally demonstrate such an instance of an absolute advantage per photon probe that is exposed to the absorbative sample...

  9. Exploring the origin of high optical absorption in conjugated polymers

    KAUST Repository

    Vezie, Michelle S.

    2016-05-16

    The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure.

  10. The effect of cutting on carbon dioxide absorption and carbohydrate ...

    African Journals Online (AJOL)

    grass) and Osteospermun sinuatum (Karoo-bush) plants during the flag leaf and flower bud stages respectively resulted in a sharp decline in net carbon dioxide absorption. As new photosynthetic material was produced the total carbon ...

  11. Overview of Resources for Geothermal Absorption Cooling for Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xiaobing [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gluesenkamp, Kyle R [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Mehdizadeh Momen, Ayyoub [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-06-01

    This report summarizes the results of a literature review in three areas: available low-temperature/coproduced geothermal resources in the United States, energy use for space conditioning in commercial buildings, and state of the art of geothermal absorption cooling.

  12. Ultraviolet light absorption of an ophthalmic formulation with Aloe extracts.

    Science.gov (United States)

    Ji, Yimei; Jia, Jicheng

    2009-09-01

    Aloin and polysaccharide present in extracts of Aloe arborescens Miller were formulated into a binary solution to protect eyes from bacterial infection and ultraviolet radiation (UVR). The UVR absorption spectrum was recorded from 190 to 440 nm using a UV spectrometer. The physical properties of the product were examined in terms of its appearance, odor, pH, viscosity, density, refractive index, and stability. The binary solution exhibited three absorption peaks in the UVA, B and C regions, respectively. Such UV absorption capability was attributed to the phenolic chromophores pertaining to aloin. The present study suggested that the formulated binary solution has potential application as an UV absorption agent with built-in antimicrobial activity.

  13. Equivalent absorption coefficients generated from frequency probability distributions

    Science.gov (United States)

    Ackerman, T. P.

    1983-01-01

    A flexible and computationally accurate method of treating aerosol scattering in spectral regions in which gaseous absorption is important is described. In the method, line-by-line absorption coefficients are computed as a function of pressure, temperature, and absorber gas for the spectral region of interest. The coefficients are sorted into a probability distribution which is converted into a cumulative probability distribution, which in turn can be inverted due to its monotonic nature. The inverted distribution is a smooth curve giving the absorption coefficient as a function of an independent variable on the domain. The frequency integration of the radiative transfer equation can then be performed by a quadrature technique with values of the absorption coefficient determined from the inverted distribution curve. The method is illustrated by applying it to the 9.6 micron band of ozone.

  14. Tunable mid-infrared absorption of metamaterial integrated with graphene

    Science.gov (United States)

    Chen, X. B.; Li, Q.; Ghosh, P.; Min, Q.

    2017-06-01

    A metal-isolator-metal (MIM) metamaterial absorber with embedded graphene shows tunable at mid-infrared frequency regime. We report tunable absorption spectra of the MIM structure for different Fermi levels of graphene.

  15. Filament characterization via resonance absorption of terahertz wave

    Science.gov (United States)

    Zheng, Zhigang; Huang, Yindong; Guo, Quan; Meng, Chao; Lü, Zhihui; Wang, Xiaowei; Zhao, Jing; Meng, Congsen; Zhang, Dongwen; Yuan, Jianmin; Zhao, Zengxiu

    2017-10-01

    In this work, we characterize the transmission properties of the focusing-laser-induced filament by using terahertz (THz) time domain spectroscopy. Significant resonance absorption of the THz wave is identified, which is attributed to the dynamic screening of the ionized electrons. The polarization and intensity of the filament-generated pulse have been varied to study their influences on the resonance absorption. Our results suggest that the electron density of the filament can be determined by fitting the phase shifts and absorption properties around the absorption. This method provides not only an alternative to the plasma diagnostics with plasma frequency at the THz range, but also a supplement to the existing generation theory of THz waves from plasma.

  16. Nitrogen-vacancy ensemble magnetometry based on pump absorption

    DEFF Research Database (Denmark)

    Ahmadi, Sepehr; El-Ella, Haitham A.R.; Hansen, Jørn B.

    2017-01-01

    We demonstrate magnetic field sensing by recording the variation in the pump light absorption with nitrogen-vacancy center ensemble. At a frequency of 10 mHz we obtain a noise floor of ~30 nT/√Hz....

  17. Luminescence and optical absorption determination in porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Nogal, U.; Calderon, A.; Marin, E.; Rojas T, J. B.; Juarez, A. G., E-mail: u_nogal@hotmail.com [IPN, Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Calz. Legaria No. 694, Col. Irrigacion, 11500 Mexico D. F. (Mexico)

    2012-10-15

    We applied the photoacoustic spectroscopy technique in order to obtain the optical absorption spectrum in porous silicon samples prepared by electrochemical anodic etching on n-type, phosphorous doped, (100)-oriented crystal-line silicon wafer with thickness of 300 {mu}m and 1-5 {omega}cm resistivity. The porous layers were prepared with etching times of 13, 20, 30, 40 and 60 minutes. Also, we realized a comparison among the optical absorption spectrum with the photoluminescence and photo reflectance ones, both obtained at room temperature. Our results show that the absorption spectrum of the samples of porous silicon depends notably of the etching time an it consist of two distinguishable absorption bands, one in the Vis region and the other one in the UV region. (Author)

  18. Enhancement of resonant absorption through excitation of SPR

    Science.gov (United States)

    Giulietti, Danilo; Calcagno, L.; Curcio, Alessandro; Cutroneo, M.; Galletti, Mario; Skala, J.; Torrisi, L.; Zimbone, M.

    2016-09-01

    In this experiment the absorption of the laser radiation impinging on polymeric films with Au nanoparticles implanted in surface was studied. By varying the polarization and the incidence angle of the laser radiation on target, the role in the laser absorption of both excitation of surface plasmons and excitation of electronic plasma waves at critical density through resonant absorption was highlighted. In conditions of p-polarized laser irradiations at 1015 W /cm2 intensity, resonant absorption can be induced in films enhancing proton and ion acceleration. Plasma on-line diagnostics is based on SiC detectors. Measurements of kinetic energy of accelerated ions indicate a significant increment using p-polarized laser light with respect to no-polarized light irradiation.

  19. Cloud Absorption Radiometer Autonomous Navigation System - CANS

    Science.gov (United States)

    Kahle, Duncan; Gatebe, Charles; McCune, Bill; Hellwig, Dustan

    2013-01-01

    CAR (cloud absorption radiometer) acquires spatial reference data from host aircraft navigation systems. This poses various problems during CAR data reduction, including navigation data format, accuracy of position data, accuracy of airframe inertial data, and navigation data rate. Incorporating its own navigation system, which included GPS (Global Positioning System), roll axis inertia and rates, and three axis acceleration, CANS expedites data reduction and increases the accuracy of the CAR end data product. CANS provides a self-contained navigation system for the CAR, using inertial reference and GPS positional information. The intent of the software application was to correct the sensor with respect to aircraft roll in real time based upon inputs from a precision navigation sensor. In addition, the navigation information (including GPS position), attitude data, and sensor position details are all streamed to a remote system for recording and later analysis. CANS comprises a commercially available inertial navigation system with integral GPS capability (Attitude Heading Reference System AHRS) integrated into the CAR support structure and data system. The unit is attached to the bottom of the tripod support structure. The related GPS antenna is located on the P-3 radome immediately above the CAR. The AHRS unit provides a RS-232 data stream containing global position and inertial attitude and velocity data to the CAR, which is recorded concurrently with the CAR data. This independence from aircraft navigation input provides for position and inertial state data that accounts for very small changes in aircraft attitude and position, sensed at the CAR location as opposed to aircraft state sensors typically installed close to the aircraft center of gravity. More accurate positional data enables quicker CAR data reduction with better resolution. The CANS software operates in two modes: initialization/calibration and operational. In the initialization/calibration mode

  20. Solar-powered absorption refrigeration system; Solarbetriebene Absorptions-Kaeltemaschine MGB - Zuerich

    Energy Technology Data Exchange (ETDEWEB)

    Corbaz, C.; Utz, C.

    2005-07-01

    This illustrated final report for the Swiss Federal Office of Energy (SFOE) reviews the project implemented at the head offices of the Migros co-operative society MGB in Zurich, Switzerland, involving cold generation using evacuated solar collectors and an absorption refrigeration system. The experience gained with this first solar powered cooling system using evacuated tube collectors located on the flat roof of the building is discussed. Considerable possibilities for the optimisation of the system are discussed, including the use of excess heat stored overnight in the warm-up phase of operation on the next day. The advantages of the correct placing of equipment rooms near to collectors and cooling-towers are discussed. The operation and characteristics of the installation in winter and summer operation are briefly described and figures on its performance and the costs involved are quoted.

  1. Ultraviolet absorption spectrum of hydrogen peroxide vapor. [for atmospheric abundances

    Science.gov (United States)

    Molina, L. T.; Schinke, S. D.; Molina, M. J.

    1977-01-01

    The ultraviolet absorption cross sections of hydrogen peroxide vapor have been determined over the wavelength range 210 to 350 nm at 296 K. At the longer wavelengths, the gas phase absorptivities are significantly larger than the corresponding values in condensed phase. The atmospheric H2O2 photodissociation rate for overhead sun at the earth's surface is estimated to be about 1.3 x 10 to the -5th/sec.

  2. FDTD modeling of solar energy absorption in silicon branched nanowires.

    Science.gov (United States)

    Lundgren, Christin; Lopez, Rene; Redwing, Joan; Melde, Kathleen

    2013-05-06

    Thin film nanostructured photovoltaic cells are increasing in efficiency and decreasing the cost of solar energy. FDTD modeling of branched nanowire 'forests' are shown to have improved optical absorption in the visible and near-IR spectra over nanowire arrays alone, with a factor of 5 enhancement available at 1000 nm. Alternate BNW tree configurations are presented, achieving a maximum absorption of over 95% at 500 nm.

  3. Slow-light enhancement of Beer-Lambert-Bouguer absorption

    DEFF Research Database (Denmark)

    Mortensen, Asger; Xiao, Sanshui

    2007-01-01

    We theoretically show how slow light in an optofluidic environment facilitates enhanced light-matter interactions, by orders of magnitude. The proposed concept provides strong opportunities for improving existing miniaturized chemical absorbance cells for Beer-Lambert-Bouguer absorption measureme......We theoretically show how slow light in an optofluidic environment facilitates enhanced light-matter interactions, by orders of magnitude. The proposed concept provides strong opportunities for improving existing miniaturized chemical absorbance cells for Beer-Lambert-Bouguer absorption...

  4. Assessment of normal incidence absorption performance of sound absorbing materials

    OpenAIRE

    Farhad Forouharmajd; Zahra Mohammadi

    2016-01-01

    Aims: The purpose of the present work was to consider the effect of different samples thicknesses on the acoustic absorption coefficient. Materials and Methods: An impedance tube was built with two microphones accordance to ISO-10534 and the American Society for Testing Materials-E1050 standards. For the measurement of absorption, the study was carried for 25 and 30 mm thicknesses of closed cell polyurethane foam, polystyrene, polyvinyl chloride (PVC), rubber, mineral wool, carpet, and gl...

  5. THz induced nonlinear absorption in ZnTe

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Jepsen, Peter Uhd

    2015-01-01

    Absorption spectra of ZnTe during strong-field THz interaction are investigated. Bleaching of the difference phonon modes below the fundamental TO mode is observed when field strengths higher than 4 MV/cm are applied.......Absorption spectra of ZnTe during strong-field THz interaction are investigated. Bleaching of the difference phonon modes below the fundamental TO mode is observed when field strengths higher than 4 MV/cm are applied....

  6. Absorption in Sport: A Cross-Validation Study

    Science.gov (United States)

    Koehn, Stefan; Stavrou, Nektarios A. M.; Cogley, Jeremy; Morris, Tony; Mosek, Erez; Watt, Anthony P.

    2017-01-01

    Absorption has been identified as readiness for experiences of deep involvement in the task. Conceptually, absorption is a key psychological construct, incorporating experiential, cognitive, and motivational components. Although, no operationalization of the construct has been provided to facilitate research in this area, the purpose of this research was the development and examination of the psychometric properties of a sport-specific measure of absorption that evolved from the use of the modified Tellegen Absorption Scale (MODTAS; Jamieson, 2005) in mainstream psychology. The study aimed to provide evidence of the psychometric properties, reliability, and validity of the Measure of Absorption in Sport Contexts (MASCs). The psychometric examination included a calibration sample from Scotland and a cross-validation sample from Australia using a cross-sectional design. The item pool was developed based on existing items from the modified Tellegen Absorption Scale (Jamieson, 2005). The MODTAS items were reworded and translated into a sport context. The Scottish sample consisted of 292 participants and the Australian sample of 314 participants. Congeneric model testing and confirmatory factor analysis for both samples and multi-group invariance testing across samples was used. In the cross-validation sample the MASC subscales showed acceptable internal consistency and construct reliability (≥0.70). Excellent fit indices were found for the final 18-item, six-factor measure in the cross-validation sample, χ(120)2 = 197.486, p sport-specific measure of absorption. The MASC provides rich research opportunities in sport psychology that can enhance the theoretical understanding between absorption and related constructs and facilitate future intervention studies. PMID:28883802

  7. Temperature measurements via narrow line laser absorption of carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Wooldridge, M.S. [Texas A and M Univ., College Station, TX (United States). Dept. of Mechanical Engineering

    1996-12-31

    Theoretical development for temperature measurements via narrow line, infrared absorption of carbon dioxide (CO{sub 2}) is presented. The proposed technique is based on rapid-scanning of two adjacent absorption line shapes. Spectroscopic considerations for sensitivity to temperature measurements are discussed. Several line pairs are evaluated, and the R(58) and R(60) transitions of the (00{sup 0}1){l_arrow}(00{sup 0}0) band are suggested for use in high temperature measurements for combustion systems.

  8. The unresolved role of dietary fibers on mineral absorption

    OpenAIRE

    Baye, K.; Guyot, Jean-Pierre; Mouquet Rivier, Claire

    2017-01-01

    Dietary fiber is a complex nutritional concept whose definition and method of analysis has evolved over time. However, literature on the role of dietary fiber on mineral bioavailability has not followed pace. Although in vitro studies revealed mineral binding properties, both animal and human studies failed to show negative effects on mineral absorption, and even in some cases reported absorption enhancing properties. The existing literature suggests that dietary fibers have negative effects ...

  9. Absorption in Sport: A Cross-Validation Study.

    Science.gov (United States)

    Koehn, Stefan; Stavrou, Nektarios A M; Cogley, Jeremy; Morris, Tony; Mosek, Erez; Watt, Anthony P

    2017-01-01

    Absorption has been identified as readiness for experiences of deep involvement in the task. Conceptually, absorption is a key psychological construct, incorporating experiential, cognitive, and motivational components. Although, no operationalization of the construct has been provided to facilitate research in this area, the purpose of this research was the development and examination of the psychometric properties of a sport-specific measure of absorption that evolved from the use of the modified Tellegen Absorption Scale (MODTAS; Jamieson, 2005) in mainstream psychology. The study aimed to provide evidence of the psychometric properties, reliability, and validity of the Measure of Absorption in Sport Contexts (MASCs). The psychometric examination included a calibration sample from Scotland and a cross-validation sample from Australia using a cross-sectional design. The item pool was developed based on existing items from the modified Tellegen Absorption Scale (Jamieson, 2005). The MODTAS items were reworded and translated into a sport context. The Scottish sample consisted of 292 participants and the Australian sample of 314 participants. Congeneric model testing and confirmatory factor analysis for both samples and multi-group invariance testing across samples was used. In the cross-validation sample the MASC subscales showed acceptable internal consistency and construct reliability (≥0.70). Excellent fit indices were found for the final 18-item, six-factor measure in the cross-validation sample, [Formula: see text] = 197.486, p sport-specific measure of absorption. The MASC provides rich research opportunities in sport psychology that can enhance the theoretical understanding between absorption and related constructs and facilitate future intervention studies.

  10. Acoustic absorption of natural gas compression facility enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Lassen, P.; Wong, G. [Noise Management Ltd., Calgary, AB (Canada)

    2009-07-01

    Noise sources at gas compressor facilities include the enclosure/building housing a gas engine and compressor, the ventilation openings, doors and windows for the enclosure, the engine air intake and exhaust, and a cooler. Accurate predictions of the noise levels inside the enclosure, the breakout noise from open windows and doors and ventilation, as well as the transmission through the walls, is necessary in order to determine cost effective noise mitigation for the facility. In order to accurately predict the sound breakout from these facilities it is necessary to know the acoustic absorption of the interior of these equipment enclosures. Although the acoustic absorption data of the wall systems may be available, the absorption attributable to the non-enclosure surfaces, the equipment and fittings, is not usually known and is difficult to predict. Since piping, instrumentation and mechanical equipment often take on a typical arrangement, shape, volumetric density and material composition, it is useful to know the typical acoustic absorption attributable to these items. In this study, reverberation time (RT) measurements were taken at 2 decommissioned gas compressor facilities in order to determine the absorption characteristics of the enclosure. The RT was measured according to ASTM C423-02a. The overall absorption coefficient of a compressor enclosure with a solid liner was found to be similar to that of steel decking. Fittings within the enclosure did not increase the high frequency absorption of the enclosure. It was concluded that room modes, structural vibrations, and fittings may serve to increase the effective absorption at frequencies below 630 Hz. Because of the small dimensions of the enclosure, low-frequency response of the room affected the reliability of the data below 160Hz. Structural vibration of the enclosure was investigated, and may considerably influence the noise breakout from the enclosure apart from the interior acoustical considerations. 4

  11. Spectrophotometer-Integrating-Sphere System for Computing Solar Absorptance

    Science.gov (United States)

    Witte, William G., Jr.; Slemp, Wayne S.; Perry, John E., Jr.

    1991-01-01

    A commercially available ultraviolet, visible, near-infrared spectrophotometer was modified to utilize an 8-inch-diameter modified Edwards-type integrated sphere. Software was written so that the reflectance spectra could be used to obtain solar absorptance values of 1-inch-diameter specimens. A descriptions of the system, spectral reflectance, and software for calculation of solar absorptance from reflectance data are presented.

  12. Percutaneous absorption of chlorhexidine in neonatal cord care.

    OpenAIRE

    Aggett, P J; Cooper, L. V.; Ellis, S H; McAinsh, J

    1981-01-01

    The percutaneous absorption of chlorhexidine during its routine use in topical antiseptic preparations used in umbilical cord care was investigated by determining plasma chlorhexidine concentrations at ages 5 and 9 days. These showed that percutaneous absorption of chlorhexidine occurred in preterm neonates treated with a 1% solution of chlorhexidine in ethanol, but not in term infants similarly treated, or in preterm infants treated only with a dusting powder containing 1% chlorhexidine and ...

  13. Neutron absorption constraints on the composition of 4 Vesta

    Science.gov (United States)

    Prettyman, Thomas H.; Mittlefehldt, David W.; Yamashita, Naoyuki; Beck, Andrew W.; Feldman, William C.; Hendricks, John S.; Lawrence, David J.; McCoy, Timothy J.; McSween, Harry Y.; Paplowski, Patrick N.; Reedy, Robert C.; Toplis, Michael J.; Le Corre, Lucille; Mizzon, Hugau; Reddy, Vishnu; Titus, Timothy N.; Raymond, Carol A.; Russell, Christopher T.

    2013-01-01

    Global maps of the macroscopic thermal neutron absorption cross section of Vesta's regolith by the Gamma Ray and Neutron Detector (GRaND) on board the NASA Dawn spacecraft provide constraints on the abundance and distribution of Fe, Ca, Al, Mg, and other rock-forming elements. From a circular, polar low-altitude mapping orbit, GRaND sampled the regolith to decimeter depths with a spatial resolution of about 300 km. At this spatial scale, the variation in neutron absorption is about seven times lower than that of the Moon. The observed variation is consistent with the range of absorption for howardite whole-rock compositions, which further supports the connection between Vesta and the howardite, eucrite, and diogenite meteorites. We find a strong correlation between neutron absorption and the percentage of eucritic materials in howardites and polymict breccias, which enables petrologic mapping of Vesta's surface. The distribution of basaltic eucrite and diogenite determined from neutron absorption measurements is qualitatively similar to that indicated by visible and near infrared spectroscopy. The Rheasilvia basin and ejecta blanket has relatively low absorption, consistent with Mg-rich orthopyroxene. Based on a combination of Fe and neutron absorption measurements, olivine-rich lithologies are not detected on the spatial scales sampled by GRaND. The sensitivity of GRaND to the presence of mantle material is described and implications for the absence of an olivine signature are discussed. High absorption values found in Vesta's “dark” hemisphere, where exogenic hydrogen has accumulated, indicate that this region is richer in basaltic eucrite, representative of Vesta's ancient upper crust.

  14. Enhanced solar light absorption of graphene by interaction with anisole

    KAUST Repository

    Kahaly, M. Upadhyay

    2014-10-01

    We study suspended graphene in contact with the organic molecule anisole to analyse the implications of the interaction for the optical absorption, using first principle calculations. Because of a weak interaction multiple orientations of the molecule with respect to the graphene sheet are possible. A substantial enhancement of the optical absorption independent of the specific orientation is observed, which is promising for energy harvesting. © 2014 Elsevier Ltd. All rights reserved.

  15. Low-Absorption Liquid Crystals for Infrared Beam Steering

    Science.gov (United States)

    2014-10-17

    SEEOR) is its relatively long optical beam path. In the VIS and NIR spectral regions, most liquid crystals have negligible absorption so that the...absorption; v.=variable intensity) [B. D. Mistry, ^ Handbook of Spectroscopic Data: Chemistry-UV, IR, PMR, CNMR and Mass Spectroscopy , Oxford, 2009...director was oriented at 45° with respect to the polarizer transmission axis. A linearly polarized He-Ne laser (>^=633nm), a tunable Argon-ion laser

  16. Dynamically tunable extraordinary light absorption in monolayer graphene

    Science.gov (United States)

    Safaei, Alireza; Chandra, Sayan; Vázquez-Guardado, Abraham; Calderon, Jean; Franklin, Daniel; Tetard, Laurene; Zhai, Lei; Leuenberger, Michael N.; Chanda, Debashis

    2017-10-01

    The high carrier mobility of graphene makes it an attractive material for electronics, however, graphene's application for optoelectronic systems is limited due to its low optical absorption. We present a cavity-coupled nanopatterned graphene absorber designed to sustain temporal and spatial overlap between localized surface plasmon resonance and cavity modes, thereby resulting in enhanced absorption up to an unprecedented value of theoretically (60 %) and experimentally measured (45 %) monolayer graphene in the technologically relevant 8-12-μm atmospheric transparent infrared imaging band. We demonstrate a wide electrostatic tunability of the absorption band (˜2 μ m ) by modifying the Fermi energy. The proposed device design allows enhanced absorption and dynamic tunability of chemical vapor deposition grown low carrier mobility graphene which provides a significant advantage over previous strategies where absorption enhancement was limited to exfoliated high carrier mobility graphene. We developed an analytical model that incorporates the coupling of the graphene electron and substrate phonons, providing valuable and instructive insights into the modified plasmon-phonon dispersion relation necessary to interpret the experimental observations. Such gate voltage and cavity tunable enhanced absorption in chemical vapor deposited large area monolayer graphene paves the path towards the scalable development of ultrasensitive infrared photodetectors, modulators, and other optoelectronic devices.

  17. Mechanical Parameters Effects on Acoustic Absorption at Polymer Foam

    Directory of Open Access Journals (Sweden)

    Lyes Dib

    2015-01-01

    Full Text Available Polymer foams have acoustic absorption properties that play an important role in reducing noise level. When the skeleton is set to motion, it is necessary to use generalized Biot-Allard model which takes into account the deformation of the skeleton and the fluid and the interactions between them. The aim of this work is to study the quality of acoustic absorption in polyurethane foam and to show the importance of the structural vibration of this foam on the absorption by varying mechanical parameters (Young’s modulus E, Poisson’s coefficient ν, structural damping factor η, and the density ρ1. We calculated the absorption coefficient analytically using classical Biot formulation (us, uf and numerically using Biot mixed formulation (us, p in 3D COMSOL Multiphysics. The obtained results are compared together and show an excellent agreement. Afterwards, we studied the effect of varying each mechanical parameter independently on the absorption in interval of ±20%. The simulations show that these parameters have an influence on the sound absorption around the resonance frequency fr.

  18. Absorption chillers integration in a combined heat and power plant

    Energy Technology Data Exchange (ETDEWEB)

    Bruno, J. C.; Fernandez, F.; Castells, F. [Barcelona Univ., Tarragona (Spain). Dept. d`Enginyeria Quimica i Bioqumica

    1996-11-01

    Inclusion of an absorption cycle within a combined heat and power plant (CHP) was evaluated. To determine the most suitable configuration of the energy network generation system and absorption chiller, a simulation and optimization model was constructed. To validate the optimization model, a case study using actual data from existing operating plants has been used. In the case described the cooling facilities from the absorption cycle were used to lower the inlet temperature to the compressor of the gas turbine to improve the overall plant efficiency. Waste steam from the steam network was used in the generator of the absorption chiller. A reduction in steam wastes, and an improvement in overall plant efficiency was observed. A simulation model of a single effect absorption chiller, using water-lithium bromide as the working fluid pair, was used to validate the methodology. Results showed that the benefits of integrating the absorption refrigeration cycle (ARC) depends directly on the refrigeration demand, and on the benefit produced by the waste steam recovered. The increase in power generation, allowing a reduction in primary energy consumption, showed a slight economic advantage over the conventional compression cycle. 13 refs., 7. tabs., 6 figs.

  19. Compressive Behaviour and Energy Absorption of Aluminium Foam Sandwich

    Science.gov (United States)

    Endut, N. A.; Hazza, M. H. F. Al; Sidek, A. A.; Adesta, E. T. Y.; Ibrahim, N. A.

    2018-01-01

    Development of materials in automotive industries plays an important role in order to retain the safety, performance and cost. Metal foams are one of the idea to evolve new material in automotive industries since it can absorb energy when it deformed and good for crash management. Recently, new technology had been introduced to replace metallic foam by using aluminium foam sandwich (AFS) due to lightweight and high energy absorption behaviour. Therefore, this paper provides reliable data that can be used to analyze the energy absorption behaviour of aluminium foam sandwich by conducting experimental work which is compression test. Six experiments of the compression test were carried out to analyze the stress-strain relationship in terms of energy absorption behavior. The effects of input variables include varying the thickness of aluminium foam core and aluminium sheets on energy absorption behavior were evaluated comprehensively. Stress-strain relationship curves was used for energy absorption of aluminium foam sandwich calculation. The result highlights that the energy absorption of aluminium foam sandwich increases from 12.74 J to 64.42 J respectively with increasing the foam and skin thickness.

  20. Some aspects of coupling-induced sound absorption in enclosures.

    Science.gov (United States)

    Sum, K S; Pan, J

    2003-08-01

    It is known that the coupling between a modally reactive boundary structure of an enclosure and the enclosed sound field induces absorption in the sound field. However, the effect of this absorption on the sound-field response can vary significantly, even when material properties of the structure and dimensions of the coupled system are not changed. Although there have been numerous investigations of coupling between a structure and an enclosed sound field, little work has been done in the area of sound absorption induced by the coupling. Therefore, characteristics of the absorption are not well understood and the extent of its influence on the behavior of the sound-field response is not clearly known. In this paper, the coupling of a boundary structure and an enclosed sound field in frequency bands above the low-frequency range is considered. Three aspects of the coupling-induced sound absorption are studied namely, the effects of exciting either the structure or the sound field directly, damping in the uncoupled sound field and damping in the uncoupled structure. The results provide an understanding of some features of the coupling-induced absorption and its significance to the sound-field response.

  1. Consistency Study of Enhanced Shortwave Cloud Absorption Using GEBA Data

    Science.gov (United States)

    Zhang, Ming-Hua; Chou, Ming-Dah (Technical Monitor)

    2001-01-01

    Under the support of this project, we have obtained the following results:(1) Shortwave radiative fluxes in current atmospheric general circulation models (GCMs) cannot simultaneously match Earth Radiation Budget Experiment (ERBE) at the top of the atmosphere (TOA) and Global Energy Balance Archive (GEBA) at the surface. This inconsistency of model results with observation is a result of insufficient absorption of solar radiation in the model atmosphere; (2) Current state-of-the art global datasets describing the energy balance of the atmosphere cannot close the atmospheric energy budget if algorithm-derived surface shortwave radiative fluxes are used. The deficient amount of 20 W/sq m is similar to the recently reported enhanced absorption of solar radiation in the atmosphere; (3) We have clarified several sampling problems in the analysis of the collocated monthly GEBA/ERBE data sets which are germane to the interpretation of the clear-sky absorption of shortwave radiation in the atmosphere. As a result, the collocated monthly ERBE/GEBA data can be effectively used to infer enhanced absorption of atmospheric radiation in measurements relative to models, but it cannot be unambiguously used to answer whether the enhanced absorption is in clouds or in clear sky. Other field data are needed to resolve this issue; and (4) Analysis of aircraft measurements during Atmospheric Radiation Measurement Enhanced Shortwave Experiment (ARESE) field campaign supports the enhanced absorption of solar radiation in clouds.

  2. Vitamin B12 absorption capacity in healthy children

    Energy Technology Data Exchange (ETDEWEB)

    Hjelt, K.; Krasilnikoff, P.A.

    1986-03-01

    B12 absorption was investigated in 47 healthy children aged 7 months to 15.8 years (median 4.9 years). The patients had either recovered from giardiasis, the post-gastroenteritis syndrome, or had celiac disease in remission (treated with a gluten-free diet). The B12 absorption was measured by a double-isotope technique using /sup 57/CoB12 and /sup 51/CrCl/sub 3/, the latter being the inabsorbable marker. The radiation dose was minimal. The results were presented as fractional absorption of B12 (FAB12). Within the different age groups, the absorption test was performed by means of the following oral amounts of B12: 0- less than 1 year, 0.5 microgram; 1-3 years: 1.7 micrograms, 4-6 years, 2.5 micrograms; 7-10 years; 3.3 micrograms; and 11-15 years, 4.5 micrograms. When using these oral amounts of B12, the medians (and ranges) of FAB12 were found to be: 1-3 years (n = 18), 37% (16-80%); 4-6 years (n = 10), 27% (19-40%); 7-10 years (n = 9), 32% (21-44%); and 11-15 years (n = 8), 27% (19-59%). The FAB12 in two children aged 7 and 11 months was 31% and 32%, respectively. These results may be interpretated as reference values for B12 absorption in children. Further absorption tests were performed in seven children representing the four age groups from 1 to 15 years. When a high oral amount of B12 was given (i.e., three times the saturation dose), the FAB12 ranged from 0 to 20% (median 9%), whereas a low amount (i.e., one-ninth of the saturation dose) produced fractional absorptions from 65 to 82% (median 74%).

  3. Paracellular absorption: a bat breaks the mammal paradigm.

    Directory of Open Access Journals (Sweden)

    Enrique Caviedes-Vidal

    Full Text Available Bats tend to have less intestinal tissue than comparably sized nonflying mammals. The corresponding reduction in intestinal volume and hence mass of digesta carried is advantageous because the costs of flight increase with load carried and because take-off and maneuverability are diminished at heavier masses. Water soluble compounds, such as glucose and amino acids, are absorbed in the small intestine mainly via two pathways, the transporter-mediated transcellular and the passive, paracellular pathways. Using the microchiropteran bat Artibeus literatus (mean mass 80.6+/-3.7 g, we tested the predictions that absorption of water-soluble compounds that are not actively transported would be extensive as a compensatory mechanism for relatively less intestinal tissue, and would decline with increasing molecular mass in accord with sieve-like paracellular absorption. Using a standard pharmacokinetic technique, we fed, or injected intraperitoneally the metabolically inert carbohydrates L-rhamnose (molecular mass = 164 Da and cellobiose (molecular mass = 342 Da which are absorbed only by paracellular transport, and 3-O-methyl-D-glucose (3OMD-glucose which is absorbed via both mediated (active and paracellular transport. As predicted, the bioavailability of paracellular probes declined with increasing molecular mass (rhamnose, 90+/-11%; cellobiose, 10+/-3%, n = 8 and was significantly higher in bats than has been reported for laboratory rats and other mammals. In addition, absorption of 3OMD-glucose was high (96+/-11%. We estimated that the bats rely on passive, paracellular absorption for more than 70% of their total glucose absorption, much more than in non-flying mammals. Although possibly compensating for less intestinal tissue, a high intestinal permeability that permits passive absorption might be less selective than a carrier-mediated system for nutrient absorption and might permit toxins to be absorbed from plant and animal material in the

  4. X-RAY ABSORPTION OF HIGH-REDSHIFT QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Eitan, Assaf; Behar, Ehud, E-mail: sassafe@tx.technion.ac.il, E-mail: behar@physics.technion.ac.il [Physics Department, Technion, Haifa 32000 (Israel)

    2013-09-01

    The soft X-ray photoelectric absorption of high-z quasars has been known for two decades, but has no unambiguous astrophysical context. We construct the largest sample to date of 58 high-redshift quasars (z > 0.45) selected from the XMM-Newton archive based on a high photon count criterion (>1800). We measure the optical depth {tau} at 0.5 keV and find that 43% of the quasars show significant absorption. We aim to find which physical parameters of the quasars, e.g., redshift, radio luminosity, radio loudness, or X-ray luminosity, drive their observed absorption. We compare the absorption behavior with redshift with the pattern expected if the diffuse intergalactic medium (IGM) is responsible for the observed absorption. We also compare the absorption with a comparison sample of gamma-ray burst (GRB) X-ray afterglows. Although the z > 2 quasar opacity is consistent with diffuse IGM absorption, many intermediate-z (0.45 < z < 2) quasars are not sufficiently absorbed for this scenario, and are appreciably less absorbed than GRBs. Only 10/37 quasars at z < 2 are absorbed, and only 5/30 radio-quiet quasars are absorbed. We find a weak correlation between {tau} and z, and an even weaker correlation between {tau} and radio luminosity. These findings lead to the conclusion that although a diffuse IGM origin for the quasar absorption is unlikely, the optical depth does seem to increase with redshift, roughly as (1 + z){sup 2.2{+-}0.6}, tending to {tau} Almost-Equal-To 0.4 at high redshifts, similar to the high-z GRBs. This result can be explained by an ionized and clumpy IGM at z < 2, and a cold, diffuse IGM at higher redshift. If, conversely, the absorption occurs at the quasar, and owing to the steep L{sub x} {proportional_to}(1 + z){sup 7.1{+-}0.5} correlation in the present sample, the host column density scales as N{sub H}{proportional_to}L{sub x}{sup 0.7{+-}0.1}.

  5. Absorption of sulfur dioxide in aqueous dispersions of dimethyl aniline

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, B.K.; Shyamal, M.; Basu, R.K. [Oil and Natural Gas Commission, Bombay (India)

    1996-06-01

    Absorption of sulfur dioxide in aqueous dispersions of dimethyl aniline (DMA) has been carried out in a laboratory stirred cell with a flat gas-liquid interface. The effects of liquid loading, gas concentrations and other parameters have been studied. The absorption rate is linear in gas concentration, and increases with increasing dispersed phase concentration. Substantial enhancement of absorption compared to that in water occurs. Emulsification of the liquid by addition of a surfactant does not increase the absorption rate. The rate of desorption of sulfur dioxide from a loaded solution at 60{degree}C remains essentially constant. A theoretical model for absorption has been developed assuming each droplet in the film to be enclosed by a spherical shell of the aqueous phase through which the solute diffuses at steady state. Comparison of the calculated enhancement factors with the experimental values confirms the validity of the model. The enhancement factor makes aqueous DMA an attractive solvent for regenerative desulfurization of stack gases. 23 refs., 13 figs.

  6. Characterization of hydrophobic nanoporous particle liquids for energy absorption

    Science.gov (United States)

    Hsu, Yi; Liu, Yingtao

    2016-04-01

    Recently, the development of hydrophobic nanoporous technologies has drawn increased attention, especially for the applications of energy absorption and impact protection. Although significant amount of research has been conducted to synthesis and characterize materials to protect structures from impact damage, the tradition methods focused on converting kinetic energy to other forms, such as heat and cell buckling. Due to their high energy absorption efficiency, hydrophobic nanoporous particle liquids (NPLs) are one of the most attractive impact mitigation materials. During impact, such particles directly trap liquid molecules inside the non-wetting surface of nanopores in the particles. The captured impact energy is simply stored temporarily and isolated from the original energy transmission path. In this paper we will investigate the energy absorption efficiency of combinations of silica nanoporous particles and with multiple liquids. Inorganic particles, such as nanoporous silica, are characterized using scanning electron microscopy. Small molecule promoters, such as methanol and ethanol, are introduced to the prepared NPLs. Their effects on the energy absorption efficiency are studied in this paper. NPLs are prepared by dispersing the studied materials in deionized water. Energy absorption efficiency of these liquids are experimentally characterized using an Instron mechanical testing frame and in-house develop stainless steel hydraulic cylinder system.

  7. Absorption degree analysis on biogas separation with ionic liquid systems.

    Science.gov (United States)

    Zhang, Xin; Zhang, Suojiang; Bao, Di; Huang, Ying; Zhang, Xiangping

    2015-01-01

    For biogas upgrading, present work mainly focuses on either thermodynamics or mass transfer properties. A systematical study on these two aspects is important for developing a new biogas separation process. In this work, a new criterion "absorption degree", which combines both thermodynamics and mass transfer properties, was proposed for the first time to comprehensively evaluate the absorption performance. Henry's law constants of CO2 and CH4 in ionic liquids-polyethylene glycol dimethyl ethers mixtures were investigated. The liquid-side mass transfer coefficients (kL) were determined. The results indicate that IL-NHD mixtures exhibit not only a high CO2/CH4 selectivity, but also a fast kL for CO2 absorption. The [bmim][NO3]+NHD mixtures present a high absorption degree value for CO2 but a low value for CH4. For presenting a highest relative absorption degree value, the 50wt% [bmim][NO3]+50wt% NHD mixture is recommended for biogas upgrading. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Resonant absorption of electromagnetic waves in transition anisotropic media.

    Science.gov (United States)

    Kim, Kihong

    2017-11-27

    We study the mode conversion and resonant absorption phenomena occurring in a slab of a stratified anisotropic medium, optical axes of which are tilted with respect to the direction of inhomogeneity, using the invariant imbedding theory of wave propagation. When the tilt angle is zero, mode conversion occurs if the longitudinal component of the permittivity tensor, which is the one in the direction of inhomogeneity in the non-tilted case, varies from positive to negative values within the medium, while the transverse component plays no role. When the tilt angle is nonzero, the wave transmission and absorption show an asymmetry under the sign change of the incident angle in a range of the tilt angle, while the reflection is always symmetric. We calculate the reflectance, the transmittance and the absorptance for several configurations of the permittivity tensor and find that resonant absorption is greatly enhanced when the medium from the incident surface to the resonance region is hyperbolic than when it is elliptic. For certain configurations, the transmittance and absorptance curves display sharp peaks at some incident angles determined by the tilt angle.

  9. Infrared Laser Therapy using IR absorption of biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Awazu, K; Ishii, K; Hazama, H, E-mail: awazu@see.eng.osaka-u.ac.jp [Medical Beam Physics Lab., Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871 (Japan)

    2011-02-01

    Since numerous characteristic absorption lines caused by molecular vibration exist in the mid-infrared (MIR) wavelength region, selective excitation or selective dissociation of molecules is possible by tuning the laser wavelength to the characteristic absorption lines of target molecules. By applying this feature to the medical fields, less-invasive treatment and non-destructive diagnosis with absorption spectroscopy are possible using tunable MIR lasers. A high-energy nanosecond pulsed MIR tunable laser was obtained with difference-frequency generation (DFG) between a Nd:YAG and a tunable Cr:forsterite lasers. The MIR-DFG laser was tunable in a wavelength range of 5.5-10 {mu}m and generated a laser pulses with an energy of up to 1.4 mJ, a pulse width of 5 ns, and a pulse repetition rate of 10 Hz. Selective removal of atherosclerotic lesion was successfully demonstrated with the MIR-DFG laser tuned at a wavelength of 5.75 {mu}m, which corresponds to the characteristic absorption of the ester bond in cholesterol esters in the atherosclerotic lesions. We have developed a non-destructive diagnostic probe with an attenuated total reflection (ATR) prism and two hollow optical fibres. An absorption spectrum of cholesterol was measured with the ATR probe by scanning the wavelength of the MIR-DFG laser, and the spectrum was in good agreement with that measured with a commercial Fourier transform infrared spectrometer.

  10. Laparoscopic sleeve gastrectomy modifies cholesterol synthesis but not cholesterol absorption.

    Science.gov (United States)

    De Vuono, S; Ricci, M A; Siepi, D; Boni, M; Gentili, A; Scavizzi, M; Daviddi, G; Labate, P; Roscini, A R; Lupattelli, G

    Each bariatric surgery procedure impacts differently on cholesterol synthesis and absorption. Although a restrictive procedure, sleeve gastrectomy resolves diabetes mellitus and, like mixed-type procedures, induces early changes in gastrointestinal hormones. To our knowledge the present study is the first to assess the effects of sleeve gastrectomy on cholesterol synthesis and absorption. 42 consecutive subjects with obesity and sleeve gastrectomy candidates were included in the study together with a control group of 20 subjects without obesity. Before sleeve gastrectomy and 10 months afterwards, all subjects underwent a clinical examination, blood tests, ultrasound visceral fat area estimation and determination of plasma lathosterol, campesterol and sitosterol concentrations. After sleeve gastrectomy, significant decreases were observed in BMI, waist circumference, visceral and subcutaneous fat, blood pressure, triglycerides, insulin and glucose levels, lathosterol and HOMA-IR. HDL-C and apolipoprotein AI levels increased significantly. No significant differences emerged in LDL-C, apolipoprotein B levels or cholesterol absorption markers. Lathosterol levels correlated significantly with BMI, visceral fat area and HOMA-IR. Differences in cholesterol intake after surgery were not significantly associated with differences in lathosterol, campesterol and sitosterol concentrations. Sleeve gastrectomy reduced the markers of cholesterol synthesis but did not modify cholesterol absorption. Changes in cholesterol synthesis and absorption were independent of variations in cholesterol intake, suggesting a specific sleeve gastrectomy-related effect. Copyright © 2016 Asia Oceania Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.

  11. In vivo studies of biotin absorption in distal rat intestine

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, B.B.; Rosenberg, I.H.

    1986-03-01

    The authors have extended their previous studies of biotin absorption in rat proximal jejunum (PJ) to examine biotin absorptive capacity of rat ileum (I) and proximal colon (PC) using in vivo intestinal loop technique. Intestinal loops (2.5 cm) were filled with 0.3 ml of solution containing (/sup 3/H)-biotin and (/sup 14/C)-inulin in phosphate buffer, pH 6.5. Biotin absorption was determined on the basis of luminal biotin disappearance after correction for inulin recovery and averaged (pmol/loop-10 min; X +/- SEM). In related experiments, 5-cm loops of PJ, distal I (DI), or PC were filled with 0.5 ml of solution of similar composition (1.0 ..mu..M biotin). The abdominal cavity was closed and the rats were allowed to recover from anesthesia, then sacrificed 3 hr after injection. Biotin absorption averaged 96.2% (PJ), 93.2% (DI), and 25.8% (PC) of the dose administered. These differences were reflected in the radioactive biotin content of plasma and intestinal loop, kidney, and liver. These data demonstrate significant biotin absorption in rat DI and PC, as required if the intestinal microflora are to be considered as a source of biotin for the host.

  12. Extreme Variability in a Broad Absorption Line Quasar

    Energy Technology Data Exchange (ETDEWEB)

    Stern, Daniel; Jun, Hyunsung D. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Mail Stop 169-221, Pasadena, CA 91109 (United States); Graham, Matthew J.; Djorgovski, S. G.; Donalek, Ciro; Drake, Andrew J.; Mahabal, Ashish A.; Steidel, Charles C. [California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Arav, Nahum; Chamberlain, Carter [Department of Physics, Virginia Tech, Blacksburg, VA 24061 (United States); Barth, Aaron J. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States); Glikman, Eilat, E-mail: daniel.k.stern@jpl.nasa.gov [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States)

    2017-04-20

    CRTS J084133.15+200525.8 is an optically bright quasar at z = 2.345 that has shown extreme spectral variability over the past decade. Photometrically, the source had a visual magnitude of V ∼ 17.3 between 2002 and 2008. Then, over the following five years, the source slowly brightened by approximately one magnitude, to V ∼ 16.2. Only ∼1 in 10,000 quasars show such extreme variability, as quantified by the extreme parameters derived for this quasar assuming a damped random walk model. A combination of archival and newly acquired spectra reveal the source to be an iron low-ionization broad absorption line quasar with extreme changes in its absorption spectrum. Some absorption features completely disappear over the 9 years of optical spectra, while other features remain essentially unchanged. We report the first definitive redshift for this source, based on the detection of broad H α in a Keck/MOSFIRE spectrum. Absorption systems separated by several 1000 km s{sup −1} in velocity show coordinated weakening in the depths of their troughs as the continuum flux increases. We interpret the broad absorption line variability to be due to changes in photoionization, rather than due to motion of material along our line of sight. This source highlights one sort of rare transition object that astronomy will now be finding through dedicated time-domain surveys.

  13. Absorption Mode FT-ICR Mass Spectrometry Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Donald F.; Kilgour, David P.; Konijnenburg, Marco; O' Connor, Peter B.; Heeren, Ronald M.

    2013-12-03

    Fourier transform ion cyclotron resonance mass spectrometry offers the highest mass resolving power for molecular imaging experiments. This high mass resolving power ensures that closely spaced peaks at the same nominal mass are resolved for proper image generation. Typically higher magnetic fields are used to increase mass resolving power. However, a gain in mass resolving power can also be realized by phase correction of the data for absorption mode display. In addition to mass resolving power, absorption mode offers higher mass accuracy and signal-to-noise ratio over the conventional magnitude mode. Here we present the first use of absorption mode for Fourier transform ion cyclotron resonance mass spectrometry imaging. The Autophaser algorithm is used to phase correct each spectrum (pixel) in the image and then these parameters are used by the Chameleon work-flow based data processing software to generate absorption mode ?Datacubes? for image and spectral viewing. Absorption mode reveals new mass and spatial features that are not resolved in magnitude mode and results in improved selected ion image contrast.

  14. Microsaccade-rate indicates absorption by music listening.

    Science.gov (United States)

    Lange, Elke B; Zweck, Fabian; Sinn, Petra

    2017-10-01

    The power of music is a literary topos, which can be attributed to intense and personally significant experiences, one of them being the state of absorption. Such phenomenal states are difficult to grasp objectively. We investigated the state of musical absorption by using eye tracking. We utilized a load related definition of state absorption: multimodal resources are committed to create a unified representation of music. Resource allocation was measured indirectly by microsaccade rate, known to indicate cognitive processing load. We showed in Exp. 1 that microsaccade rate also indicates state absorption. Hence, there is cross-modal coupling between an auditory aesthetic experience and fixational eye movements. When removing the fixational stimulus in Exp. 2, saccades are no longer generated upon visual input and the cross-modal coupling disappeared. Results are interpreted in favor of the load hypothesis of microsaccade rate and against the assumption of general slowing by state absorption. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  15. Absorption and emission spectroscopic characterisation of 8-amino-riboflavin

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, A.; Zirak, P. [Institut II - Experimentelle und Angewandte Physik, Universitaet Regensburg, Universitaetsstrasse 31, D-93053 Regensburg (Germany); Penzkofer, A., E-mail: alfons.penzkofer@physik.uni-regensburg.de [Institut II - Experimentelle und Angewandte Physik, Universitaet Regensburg, Universitaetsstrasse 31, D-93053 Regensburg (Germany); Mathes, T.; Hegemann, P. [Institut fuer Biologie/Experimentelle Biophysik, Humboldt Universitaet zu Berlin, Invalidenstrasse 42, D-10115 Berlin (Germany); Mack, M. [Institut fuer Technische Mikrobiologie, Hochschule Mannheim, Paul-Wittsack-Str. 10, D-68163 Mannheim (Germany); Ghisla, S. [Universitaet Konstanz, Fakultaet fuer Biologie, P.O. Box 5560-M644, D-78457 Konstanz (Germany)

    2009-10-16

    The flavin dye 8-amino-8-demethyl-D-riboflavin (AF) in the solvents water, DMSO, methanol, and chloroform/DMSO was studied by absorption and fluorescence spectroscopy. The first absorption band is red-shifted compared to riboflavin, and blue-shifted compared to roseoflavin (8-dimethylamino-8-demethyl-D-riboflavin). The fluorescence quantum yield of AF in the studied solvents varies between 20% and 50%. The fluorescence lifetimes were found to be in the 2-5 ns range. AF is well soluble in DMSO, weakly soluble in water and methanol, and practically insoluble in chloroform. The limited solubility causes AF aggregation, which was seen in differences between measured absorption spectra and fluorescence excitation spectra. Light scattering in the dye absorption region is discussed and approximate absorption cross-section spectra are determined from the combined measurement of transmission and fluorescence excitation spectra. The photo-stability of AF was studied by prolonged light exposure. The photo-degradation routes of AF are discussed.

  16. Polarized absorption in determination of impurities in olive oil

    Science.gov (United States)

    Alias, A. N.; Zabidi, Z. M.; Yaacob, Y.; Amir, I. S.; Alshurdin, S. H. N.; Aini, N. A.

    2017-08-01

    The effect of impurities in olive oil blending with palm oil was characterized using polarized absorption method. Polarized absorption was based on the absorption of light which vibrating in a particular plane to pass through the sample. This polarized light allowed the molecule to absorb at the specific orientation. There were four samples have been prepared that were 100:0, 70:30, 50:50 and 0:100 with volume ratio of the olives to palm oil. Two linear polarizers were mounting between the samples in order to get linearly polarized. This specific orientation was affected the absorption spectra of the sample. The results have shown that the analyzing polarizer with angle 00 has bell shape spectra. All the orientation of analyzing polarizer had shown the maximum current output at 100% olive oil. Whereas 100% palm oil has shown the minimum current output. The changing in absorption spectra indicates that the anisotropic properties of each sample were different due to the present of impurities.

  17. Optomechanically induced absorption in parity-time-symmetric optomechanical systems

    Science.gov (United States)

    Zhang, X. Y.; Guo, Y. Q.; Pei, P.; Yi, X. X.

    2017-06-01

    We explore the optomechanically induced absorption (OMIA) in a parity-time- (PT -) symmetric optomechanical system (OMS). By numerically calculating the Lyapunov exponents, we find out the stability border of the PT -symmetric OMS. The results show that in the PT -symmetric phase the system can be either stable or unstable depending on the coupling constant and the decay rate. In the PT -symmetric broken phase the system can have a stable state only for small gain rates. By calculating the transmission rate of the probe field, we find that there is an inverted optomechanically induced transparency (OMIT) at δ =-ωM and an OMIA at δ =ωM for the PT -symmetric optomechanical system. At each side of δ =-ωM there is an absorption window due to the resonance absorption of the two generated supermodes. Comparing with the case of optomechanics coupled to a passive cavity, we find that the active cavity can enhance the resonance absorption. The absorption rate at δ =ωM increases as the coupling strength between the two cavities increases. Our work provides us with a promising platform for controlling light propagation and light manipulation in terms of PT symmetry, which might have potential applications in quantum information processing and quantum optical devices.

  18. Laser-ultrasonic absorption measurements in low carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, A.; Lord, M.; Levesque, D.; Dubois, M.; Bussiere, J.F. [Institut des Materiaux Industriels, Boucherville, Que. (Canada)

    2000-09-28

    We have refined the contactless laser-ultrasound reverberation technique to measure ultrasonic absorption on small metallic samples. In this technique, a sample is supported by a holder which is ultrasonically decoupled from the sample. A pulsed laser is used to generate an acoustic pulse. After the pulse has mode converted and scattered sufficiently to fully insonify the sample, the decrease in the noise-like ultrasonic signal is recorded as a function of time using a laser-interferometer. A joint time-frequency analysis technique is used to extract an absorption spectrum from the signal. In this paper, the technique is demonstrated in a frequency bandwidth ranging from 1 to 7 MHz, and in a dynamic range of 0.003 to 0.3 dB {mu}s{sup -1}. Measurements made on samples of three low-carbon steel grades, namely ultra low carbon (ULC), low carbon (LC), and high strength, low-alloy steels (HSLA), clearly show that ultrasonic absorption varies with steel grade. The technique was utilized to study the effect of a magnetic field on the ultrasonic absorption of an annealed ultra low carbon steel sample. It was found that magnetoelastic effects are responsible for a large fraction of the total absorption. (orig.)

  19. Phonon-assisted absorption of excitons in Cu2O

    Science.gov (United States)

    Schöne, Florian; Stolz, Heinrich; Naka, Nobuko

    2017-09-01

    The basic theoretical foundation for the modeling of phonon-assisted absorption spectra in direct band-gap semiconductors, introduced by Elliott 60 years ago [R. J. Elliott, Phys. Rev. 108, 1384 (1957), 10.1103/PhysRev.108.1384] using second order perturbation theory, results in a square root shaped dependency close to the absorption edge. A careful analysis of the experiments [N. Naka et al., Jpn. J. Appl. Phys. 44, 5096 (2005), 10.1143/JJAP.44.5096] reveals that for the yellow S excitons in Cu2O the lineshape does not follow that square root dependence. The reexamination of the theory shows that the basic assumptions of constant matrix elements and constant energy denominators is invalid for semiconductors with dominant exciton effects like Cu2O , where the phonon-assisted absorption proceeds via intermediate exciton states. The overlap between these and the final exciton states strongly determines the dependence of the absorption on the photon energy. To describe the experimental observed line shape of the indirect absorption of the yellow S exciton states we find it necessary to assume a momentum dependent deformation potential for the optical phonons.

  20. Drug gastrointestinal absorption in rat: Strain and gender differences.

    Science.gov (United States)

    Oltra-Noguera, Davinia; Mangas-Sanjuan, Victor; González-Álvarez, Isabel; Colon-Useche, Sarin; González-Álvarez, Marta; Bermejo, Marival

    2015-10-12

    Predictive animal models of intestinal drug absorption are essential tools in drug development to identify compounds with promising biopharmaceutical properties. In situ perfusion absorption studies are routinely used in the preclinical setting to screen drug candidates. The objective of this work is to explore the differences in magnitude and variability on intestinal absorption associated with rat strain and gender. Metoprolol and Verapamil absorption rate coefficients were determined using the in situ closed loop perfusion model in four strains of rats and in both genders. Strains used were Sprague-Dawley, Wistar-Han, Wistar-Unilever, Long-Evans and CD∗IGS. In the case of Metoprolol only CD∗IGS and Wistar Unilever showed differences between males and females. For Verapamil, Wistar Han and Sprague-Dawley strains do not show differences between male and female rats. That means that in these strains permeability data from male and female could be combined. In male rats, which are commonly used for permeability estimation, there were differences for Metoprolol permeability between Sprague-Dawley (with lower permeability values) and the other strains, while for Verapamil Sprague-Dawley and Wistar-Han showed the lower permeability values. In conclusion, the selection of rat's strain and gender for intestinal absorption experiments is a relevant element during study design and data from different strains may not be always comparable. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Absorption of water and lubricating oils into porous nylon

    Science.gov (United States)

    Bertrand, P. A.

    1995-01-01

    Oil and water absorption from air into sintered porous nylon can be described by infiltration into the pores of the material. This process can be modeled by a diffusion-like mechanism. For water absorption, we find a formal diffusion coefficient of 1.5 x 10(exp -4)sq cm/min when the nylon is initially dry. The diffusion coefficient is 4 x 10(exp -6)sq cm/min when the nylon is oil-impregnated prior to air exposure. In a 52% RH atmosphere, dry nylon absorbs 3% w/w water, and oil-impregnated nylon absorbs 0.6% w/w water. For oil absorption there are three steps: (1) surface absorption and infiltration into (2) larger and (3) smaller pores. Surface absorption is too fast to be measured in these experiments. The diffusion coefficient for the second step is 6 x 10(exp -4)sq cm/min for SRG-60 oil into dry nylon and 4 x 10(exp -4)sq cm/min for air-equilibrated nylon. The diffusion coefficient for the third step is about 1 x 10(exp -6)sq cm/min for both cases. The total amount of oil absorbed is 31% w/w. The interaction between water and nylon is not as strong as that between water and cotton-phenolic: oil can replace water, and only a small amount of water can enter previously oil-impregnated nylon.

  2. Credibility judgments of narratives: language, plausibility, and absorption.

    Science.gov (United States)

    Nahari, Galit; Glicksohn, Joseph; Nachson, Israel

    2010-01-01

    Two experiments were conducted in order to find out whether textual features of narratives differentially affect credibility judgments made by judges having different levels of absorption (a disposition associated with rich visual imagination). Participants in both experiments were exposed to a textual narrative and requested to judge whether the narrator actually experienced the event he described in his story. In Experiment 1, the narrative varied in terms of language (literal, figurative) and plausibility (ordinary, anomalous). In Experiment 2, the narrative varied in terms of language only. The participants' perceptions of the plausibility of the story described and the extent to which they were absorbed in reading were measured. The data from both experiments together suggest that the groups applied entirely different criteria in credibility judgments. For high-absorption individuals, their credibility judgment depends on the degree to which the text can be assimilated into their own vivid imagination, whereas for low-absorption individuals it depends mainly on plausibility. That is, high-absorption individuals applied an experiential mental set while judging the credibility of the narrator, whereas low-absorption individuals applied an instrumental mental set. Possible cognitive mechanisms and implications for credibility judgments are discussed.

  3. Development of an Ionic-Liquid Absorption Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, Don

    2011-03-29

    Solar Fueled Products (SFP) is developing an innovative ionic-liquid absorption heat pump (ILAHP). The development of an ILAHP is extremely significant, as it could result in annual savings of more than 190 billion kW h of electrical energy and $19 billion. This absorption cooler uses about 75 percent less electricity than conventional cooling and heating units. The ILAHP also has significant environmental sustainability benefits, due to reduced CO2 emissions. Phase I established the feasibility and showed the economic viability of an ILAHP with these key accomplishments: • Used the breakthrough capabilities provided by ionic liquids which overcome the key difficulties of the common absorption coolers. • Showed that the theoretical thermodynamic performance of an ILAHP is similar to existing absorption-cooling systems. • Established that the half-effect absorption cycle reduces the peak generator temperature, improving collector efficiency and reducing collector area. • Component testing demonstrated that the most critical components, absorber and generator, operate well with conventional heat exchangers. • Showed the economic viability of an ILAHP. The significant energy savings, sustainability benefits, and economic viability are compelling reasons to continue the ILAHP development.

  4. Calculating the absorption of HF radio waves in the ionosphere

    Science.gov (United States)

    Zawdie, K. A.; Drob, D. P.; Siskind, D. E.; Coker, C.

    2017-06-01

    It has long been known that the ionospheric absorption of HF radio waves is dependent on the electron density in the ionosphere. This paper examines two aspects of the absorption calculation that have not been as thoroughly investigated. First, the correct method to calculate ionospheric absorption is explored; while the Sen Wyller ray trace formulation is generally cited as the best approximation in the D and E regions of the ionosphere, the Appleton-Hartree formulation is more consistent with the theory in the F region of the ionosphere. It is shown that either ray trace formulation can be used to calculate ionospheric absorption if the correct collision frequencies are utilized. Another frequently overlooked aspect of the attenuation calculation are the variations in the electron-neutral and electron-ion collision frequencies as a function of local time, season, latitude, and solar cycle. These variations result in differences on the order of 30% in the total ionospheric attenuation and should be included in absorption calculations.

  5. Does carnitine have a role in fat absorption

    Energy Technology Data Exchange (ETDEWEB)

    Leichter, J.; Ottem, A.; Hahn, P.

    1987-08-24

    The effect of D-carnitine and tetradecylglycidic acid (TDGA), an inhibitor of carnitine palmitoyltransferase, on intestinal absorption of palmitic acid was determined. The proximal intestinal segment was ligated in adult male rats and filled with 0.5 ..mu..Ci of /sup 14/C-palmitic acid alone or with either D-carnitine or TDGA. Thirty minutes alter the radioactivity was determined in the intestinal lumen, intestinal wall and plasma. The absorption of palmitic acid was decreased in the presence of D-carnitine (10 mg/ml) as evidenced by significantly lower levels of radioactivity in the gut wall and the plasma and by significantly greater residual radioactivity in the lumenal contents. L-carnitine had no effect on plasma radioactivity but if D- and L-carnitine were given together the effect of D-carnitine was still in evidence. TDGA also inhibited intestinal absorption of palmitic acid. 8 references, 2 tables.

  6. Influence of absorption in linear polarization imaging of melanoma tissues

    Directory of Open Access Journals (Sweden)

    Dongzhi Li

    2014-05-01

    Full Text Available The contrast mechanism of different polarization imaging techniques for melanoma in mouse skin is studied using both experiments and Monte Carlo simulations. Total intensity, linear polarization difference imaging (DPI, degree of polarization imaging (DOPI and rotating linear polarization imaging (RLPI are applied and the relative contrasts of these polarization imaging methods between the normal and cancerous tissues are compared. A two-layer absorption-scattering model is proposed to explain the contrast mechanism of the polarization imaging for melanoma. By taking into account of both scattering of symmetrical and asymmetrical scatterers and absorption of inter-scatterer medium, the two-layer model reproduces the relative contrasts for polarization images observed in experiments. The simulation results also show that, the parameters of polarization imaging change more dramatically with the variation of absorption in the bottom layer than the top layer.

  7. Broadband metamaterial for optical transparency and microwave absorption

    Science.gov (United States)

    Zhang, Cheng; Cheng, Qiang; Yang, Jin; Zhao, Jie; Cui, Tie Jun

    2017-04-01

    We present a metamaterial for simultaneous optical transparency and microwave absorption in broadband, which can be used as an optically transparent radar-wave absorber. The proposed metamaterial absorber is made of windmill-shaped elements with the reflection spectra featured by three absorption bands. By properly tailoring the resonances of the structure, we achieve the optimized metamaterial absorptivity that is greater than 90% from 8.3 to 17.4 GHz. In the meantime, excellent optical transmittance is achieved by use of the indium tin oxide (ITO) film with moderate surface resistance, implying that the optical properties of the metamaterial are hardly affected by the periodic meta-atoms. Both numerical simulations and experimental results demonstrate the good performance of the proposed metamaterial, thereby enabling a wide range of applications such as ultrathin detectors and photovoltaic solar cells in the future.

  8. Anomalous sound absorption in lattices of cylindrical perforated shells

    Science.gov (United States)

    García-Chocano, Victor M.; Sánchez-Dehesa, José

    2015-03-01

    This work reports the enhancement of sound absorption by sonic crystals slabs made of cylindrical perforated shells. These building units, with perforations of millimeter size, show small losses and cannot explain the strong absorption observed at some specific frequencies when the slabs consist of just a few number of rows. It is found that this phenomenon is due to a resonant Wood anomaly which occurs when the incident wave couples with a leaky guided mode supported by the slab. This effect results in an enhancement of the absorption, since the energy transferred to the guided mode travels within the slab, along a direction perpendicular to the incident one. Multiple scattering and finite element simulations give support to the proposed behavior, the transmittance results being in good agreement with experimental data previously reported.

  9. Topological and non inertial effects on the interband light absorption

    Science.gov (United States)

    Rojas, Moises; Filgueiras, Cleverson; Brandão, Julio; Moraes, Fernando

    2018-02-01

    In this work, we investigate the combined influence of the nontrivial topology introduced by a disclination and non inertial effects due to rotation, in the energy levels and the wave functions of a noninteracting electron gas confined to a two-dimensional pseudoharmonic quantum dot, under the influence of an external uniform magnetic field. The exact solutions for energy eigenvalues and wave functions are computed as functions of the applied magnetic field strength, the disclination topological charge, magnetic quantum number and the rotation speed of the sample. We investigate the modifications on the light interband absorption coefficient and absorption threshold frequency. We observe novel features in the system, including a range of magnetic field without corresponding absorption phenomena, which is due to a tripartite term of the Hamiltonian, involving magnetic field, the topological charge of the defect and the rotation frequency.

  10. Sound absorption of textile material using a microfibres resistive layer

    Science.gov (United States)

    Segura Alcaraz, M. P.; Bonet-Aracil, M.; Segura Alcaraz, J. G.; Montava Seguí, I.

    2017-10-01

    Acoustic comfort is a basic human need. One of the adverse effects of noise is its interference with speech discrimination. Textile materials are suitable to be used as sound absorptive materials and thus help to improve acoustic comfort in rooms. Micro-fibre fabrics can be considered as better sound absorbers than regular fibre fabrics mainly due to the higher surface of its fibres and bigger contact area with the air thus, allowing greater dissipation of sound energy. In this work, the use of a microfibre woven fabric as an upstream layer is analysed considering acoustic issues. Authors demonstrate it improves the sound absorption of a polyester nonwoven, resulting in a material suitable for absorption at the sound frequencies of the human voice.

  11. Stochastic Approach to Phonon-Assisted Optical Absorption.

    Science.gov (United States)

    Zacharias, Marios; Patrick, Christopher E; Giustino, Feliciano

    2015-10-23

    We develop a first-principles theory of phonon-assisted optical absorption in semiconductors and insulators which incorporates the temperature dependence of the electronic structure. We show that the Hall-Bardeen-Blatt theory of indirect optical absorption and the Allen-Heine theory of temperature-dependent band structures can be derived from the present formalism by retaining only one-phonon processes. We demonstrate this method by calculating the optical absorption coefficient of silicon using an importance sampling Monte Carlo scheme, and we obtain temperature-dependent line shapes and band gaps in good agreement with experiment. The present approach opens the way to predictive calculations of the optical properties of solids at finite temperature.

  12. Absorption and metabolic fate of bioactive dietary benzoxazinoids in humans

    DEFF Research Database (Denmark)

    Adhikari, Khem B; Laursen, Bente B; Gregersen, Per L

    2013-01-01

    glycosides, the reduction of hydroxamic acid glycosides, glucuronidation, and sulfation were the main mechanisms of the absorption and metabolism of benzoxazinoids. Conclusion These results indicate that following ingestion in healthy humans, a range of unmetabolized bioactive dietary benzoxazinoids...... of bioactive benzoxazinoids in humans. Methods and results The absorption, metabolism, and excretion of ten different dietary benzoxazinoids were examined by LC-MS/MS by analyzing plasma and urine from 20 healthy human volunteers after daily intake of 143 μmol of total benzoxazinoids from rye bread and rye...... benzoxazinoids with abundant HBOA-Glc (219 nmol × μmol−1 of creatinine). The sulfate and glucuronide conjugates of 2-hydroxy-1,4-benzoxazin-3-one (HBOA) and 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA) were detected in plasma and urine, indicating substantial phase II metabolism. Direct absorption of lactam...

  13. Critical discussion on the UV absorption properties of Earth's atmosphere

    Science.gov (United States)

    Döhring, Thorsten

    2017-08-01

    Suńs ultraviolet radiation is classified into UV-A, UV-B, and UV-C bands. Thereby UV-A passes through Eart&hacute;s atmosphere, while UV-B is partially absorbed by ozone. The limitations of the commonly accepted statement, that UV-C is always completely absorbed by Eart&hacute;s atmosphere, are discussed critically. Below 200 nm the solar spectrum is strongly absorbed by molecular oxygen. The stratospheric ozone layer has strong absorption between 200 nm and 300 nm. However, the "ozone hole" increases UV-B radiation just below 300 nm and may also open a transmitting atmospheric window for harmful UV-C at the overlap region between oxygen absorption and ozone absorption.

  14. Defects and the optical absorption in nanocrystalline ZnO

    Science.gov (United States)

    Dutta, Sreetama; Chattopadhyay, Sanjay; Sutradhar, Manas; Sarkar, Anindya; Chakrabarti, Mahuya; Sanyal, Dirtha; Jana, Debnarayan

    2007-06-01

    The correlation between the structural and optical properties of mechanically milled high purity ZnO powder is reported in the present work. Reduction of average grain size and enhancement of strain as a result of milling have been estimated from the broadening of x-ray powder diffraction patterns. After milling, the optical bandgap, revealed from absorption spectroscopy, has been red-shifted and the width of the localized states, calculated from the analysis of the Urbach tail below the absorption edge, has been extended more and more into the bandgap. Moreover, the band tailing parameter is seen to vary exponentially with the inverse of the grain size. Finally, the positron annihilation technique has been employed to identify the nature of defects present (or generated due to milling) in the system and thereby to correlate the defect mediated modification of optical absorption in ZnO.

  15. Defects and the optical absorption in nanocrystalline ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Sreetama [Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700 009 (India); Chattopadhyay, Sanjay [Department of Physics, Taki Government College, Taki 743429 (India); Sutradhar, Manas [Department of Chemistry, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700 009 (India); Sarkar, Anindya [Department of Physics, Bangabasi Morning College, 19 Rajkumar Chakraborty Sarani, Kolkata 700 009 (India); Chakrabarti, Mahuya [Variable Energy Cyclotron Centre, 1/AF, Bidhannagar, Kolkata 700 064 (India); Sanyal, Dirtha [Variable Energy Cyclotron Centre, 1/AF, Bidhannagar, Kolkata 700 064 (India); Jana, Debnarayan [Department of Physics, University of Calcutta, 92 Acharya Prafulla Chandra Road, Kolkata 700 009 (India)

    2007-06-13

    The correlation between the structural and optical properties of mechanically milled high purity ZnO powder is reported in the present work. Reduction of average grain size and enhancement of strain as a result of milling have been estimated from the broadening of x-ray powder diffraction patterns. After milling, the optical bandgap, revealed from absorption spectroscopy, has been red-shifted and the width of the localized states, calculated from the analysis of the Urbach tail below the absorption edge, has been extended more and more into the bandgap. Moreover, the band tailing parameter is seen to vary exponentially with the inverse of the grain size. Finally, the positron annihilation technique has been employed to identify the nature of defects present (or generated due to milling) in the system and thereby to correlate the defect mediated modification of optical absorption in ZnO.

  16. Photothermal detuning for absorption measurement of optical coatings.

    Science.gov (United States)

    Hao, Honggang; Li, Bincheng

    2008-01-10

    A simple and sensitive photothermal technique--photothermal detuning, in which the spectral shift of an optical coating caused by absorption-induced temperature rise is used to measure the photothermal signal--and its application for the absorption measurement of coated optical components are developed theoretically and experimentally in detail for the first time to the best of our knowledge. The theoretical description of the photothermal detuning signal with a continuous-wave modulated laser beam excitation is presented. Experiments are conducted with a highly reflective coating used at 532 nm to measure the photothermal detuning signal and to evaluate the absorption at 532 nm by detecting the spectral shift with a probe beam at a wavelength of 632.8 nm. By optimizing the incident angle of the probe beam, the amplitude of the photothermal detuning signal is maximized. Good agreement is obtained between the experimental results and the theoretical predictions.

  17. EU Structural Funds Absorption in Romania: Obstacles and Issues

    Directory of Open Access Journals (Sweden)

    GHEORGHE ZAMAN

    2011-06-01

    Full Text Available Romania’s absorption capacity of EU structural and cohesion funds is based on the degree of implementation of Sectoral Operational Programmes (SOP 2007-2013 within SOP Environment and plays a central role in view of its complex relationships (horizontal and vertical with other SOPs.The present paper analyses the absorption capacity of SOPs in Romania, paying a special attention to SOP Environment, which can be considered an important tool for improving eco-efficiency standards and greening the economic growth. The research is focusing on cases and factors of weak absorption of Structural Funds in Romania under the current economic crisis circumstances as well as on some ways of improving the situation in the future.

  18. Complex soliton bunching patterns induced by nonsaturable absorption

    Science.gov (United States)

    Chen, Weicheng; Luo, Aiping

    2017-10-01

    A fiber laser with a semiconductor saturable absorption mirror (SESAM) and a graphene-polymer composite (GPC) film is constructed for achieving different soliton bunching patterns. The SESAM is used as a mode locker for self-started pulse generation, while the GPC provides a nonsaturable absorption effect for achieving a bunching in the laser cavity. There are three extra temporal patterns observed in the experiments through adjusting polarization controllers. They are chaotic bunching, weak coherent bunching and modulated harmonic bunching. The experimental investigation shows that dynamic nonsaturable absorption effect of an absorber is beneficial for generating different bunching patterns. Our work can have a deeper understanding of the formation of the complex soliton bunching patterns in pulsed lasers.

  19. Magnetic and solar effects on ionospheric absorption at high latitude

    Directory of Open Access Journals (Sweden)

    M. Pietrella

    2002-06-01

    Full Text Available Some periods of intense solar events and of strong magnetic storms have been selected and their effects on the ionospheric D region have been investigated on the basis of ionospheric absorption data derived from riometer measurements made at the Italian Antarctic Base of Terra Nova Bay (geographic coordinates: 74.69 S, 164.12 E; geomagnetic coordinates: 77.34 S, 279.41 E. It was found that sharp increases in ionospheric absorption are mainly due to solar protons emission with an energy greater than 10 MeV. Moreover, the day to night ratios of the ionospheric absorption are greater than 2 in the case of strong events of energetic protons emitted by the Sun, while during magnetic storms, these ratios range between 1 and 2.

  20. Thermal properties of carbon black aqueous nanofluids for solar absorption

    Directory of Open Access Journals (Sweden)

    Han Dongxiao

    2011-01-01

    Full Text Available Abstract In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.

  1. Deep subwavelength acoustic metamaterial for low-frequency sound absorption

    Science.gov (United States)

    Tang, Yufan; Xin, Fengxian; Huang, Lixi; Lu, Tianjian

    2017-05-01

    A novel class of low-frequency sound absorbers based on a honeycomb sandwich panel is theoretically designed and numerically demonstrated. The absorber with a remarkably small thickness (e.g., 1/131 of wavelength) is comprised of a perforated facesheet, a perforated honeycomb core and a non-perforated back panel. Built upon the classical microperforated panel absorber (MPPA), the idea of introducing a perforated honeycomb core which creates a double-layer perforated absorber (DLPA) without adding to the total thickness greatly enhances the low-frequency absorption performance. Theoretical predictions of the sound absorption coefficient are obtained and compared with numerical simulations obtained using the finite element method (FEM). A good agreement is achieved. The proposed sound absorber is promising for low-frequency noise absorption especially when limited space and high mechanical stiffness/strength are simultaneously demanded.

  2. Absorption enhancement of a dual-band metamaterial absorber

    Science.gov (United States)

    Zhong, Min; Han, Gui Ming; Liu, Shui Jie; Xu, Bang Li; Wang, Jie; Huang, Hua Qing

    2017-02-01

    In this paper, we propose and fabricate a dual-band metamaterial absorber in 6-24 THz region. Electric field distribution reveal that the first absorption band is obtained from localized surface plasmon (LSP) modes which are excited both on inside and outside edges of each circular-patterned metal-dielectric stack, while the second absorption band is excited by LSP modes on outside edges of each stack. Measured results indicate that the absorption band width can be tuned by increasing the radius of circular-patterned layers or reducing the thickness of dielectric spacing layers. Moreover, the designed dual-band metamaterial absorber is independent on circular-patterned dielectric layer combinations.

  3. Backscatter absorption gas imaging systems and light sources therefore

    Energy Technology Data Exchange (ETDEWEB)

    Kulp, Thomas Jan [Livermore, CA; Kliner, Dahv A. V. [San Ramon, CA; Sommers, Ricky [Oakley, CA; Goers, Uta-Barbara [Campbell, NY; Armstrong, Karla M [Livermore, CA

    2006-12-19

    The location of gases that are not visible to the unaided human eye can be determined using tuned light sources that spectroscopically probe the gases and cameras that can provide images corresponding to the absorption of the gases. The present invention is a light source for a backscatter absorption gas imaging (BAGI) system, and a light source incorporating the light source, that can be used to remotely detect and produce images of "invisible" gases. The inventive light source has a light producing element, an optical amplifier, and an optical parametric oscillator to generate wavelength tunable light in the IR. By using a multi-mode light source and an amplifier that operates using 915 nm pump sources, the power consumption of the light source is reduced to a level that can be operated by batteries for long periods of time. In addition, the light source is tunable over the absorption bands of many hydrocarbons, making it useful for detecting hazardous gases.

  4. Control of gain/absorption in tunable hyperbolic metamaterials.

    Science.gov (United States)

    Janaszek, Bartosz; Tyszka-Zawadzka, Anna; Szczepański, Paweł

    2017-06-12

    In this paper, the possibility of shaping the gain/absorption spectrum in tunable hyperbolic metamaterial (THMM) composed of subsequent layers of graphene and active/passive material by external biasing is demonstrated. For the first time it has been shown that resonance transitions between different dispersion regimes, i.e., Type I HMM→elliptic, elliptic→Type II HMM, elliptic→Type I HMM, are accompanied by interesting optical effects, such as anisotropic effective gain/absorption enhancement or electromagnetic transparency, all controllable by external voltage. We believe that this kind of tunable metamaterial could lay the foundation for a new class of active/passive media with controllable gain/absorption or electromagnetic transparency.

  5. Tunable enhanced optical absorption of graphene using plasmonic perfect absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yijun [Institute of Optoelectronic Technology, Department of Electronic Engineering, Xiamen University, Xiamen 361005 (China); Institute of Electromagnetics and Acoustics, Department of Electronic Science, Xiamen University, Xiamen 361005 (China); Zhu, Jinfeng, E-mail: nanoantenna@hotmail.com [Institute of Electromagnetics and Acoustics, Department of Electronic Science, Xiamen University, Xiamen 361005 (China); Liu, Qing Huo [Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina 27708 (United States)

    2015-01-26

    Enhancement and manipulation of light absorption in graphene is a significant issue for applications of graphene-based optoelectronic devices. In order to achieve this purpose in the visible region, we demonstrate a design of a graphene optical absorber inspired by metal-dielectric-metal metamaterial for perfect absorption of electromagnetic waves. The optical absorbance ratios of single and three atomic layer graphene are enhanced up to 37.5% and 64.8%, respectively. The graphene absorber shows polarization-dependence and tolerates a wide range of incident angles. Furthermore, the peak position and bandwidth of graphene absorption spectra are tunable in a wide wavelength range through a specific structural configuration. These results imply that graphene in combination with plasmonic perfect absorbers have a promising potential for developing advanced nanophotonic devices.

  6. Broadband solar absorption enhancement via periodic nanostructuring of electrodes.

    KAUST Repository

    Adachi, Michael M

    2013-10-14

    Solution processed colloidal quantum dot (CQD) solar cells have great potential for large area low-cost photovoltaics. However, light utilization remains low mainly due to the tradeoff between small carrier transport lengths and longer infrared photon absorption lengths. Here, we demonstrate a bottom-illuminated periodic nanostructured CQD solar cell that enhances broadband absorption without compromising charge extraction efficiency of the device. We use finite difference time domain (FDTD) simulations to study the nanostructure for implementation in a realistic device and then build proof-of-concept nanostructured solar cells, which exhibit a broadband absorption enhancement over the wavelength range of λ = 600 to 1,100 nm, leading to a 31% improvement in overall short-circuit current density compared to a planar device containing an approximately equal volume of active material. Remarkably, the improved current density is achieved using a light-absorber volume less than half that typically used in the best planar devices.

  7. UV absorption cross-sections of a series of dimethylbenzaldehydes.

    Science.gov (United States)

    El Dib, G; Chakir, A; Mellouki, A

    2008-09-18

    The ultraviolet absorption cross-sections of 2,4-, 2,5-, 2,6-, 3,4- and 3,5- dimethylbenzaldehydes are reported in the wavelength range 240-320 nm. The measurements were carried out in the temperature range 318-363 K using two different experimental systems (D 2 lamp-monochromator and D 2 lamp-diode array). The absorption spectra of the five aldehydes have been found to exhibit relatively high absorption cross-sections in the region of the tropospheric interest with maxima around 290 nm. This work provides the first UV cross-section measurements for these aromatic aldehydes. The obtained cross-section values enable us to estimate the tropospheric photolysis lifetimes of these compounds. The results suggest that photolysis could be an important removal process for these species in the troposphere.

  8. An effective way to reduce water absorption to terahertz

    Science.gov (United States)

    Wu, Yaxiong; Su, Bo; He, Jingsuo; Zhang, Cong; Zhang, Hongfei; Zhang, Shengbo; Zhang, Cunlin

    2018-01-01

    Since many vibrations and rotational levels of biomolecules fall within the THz band, THz spectroscopy can be used to identify biological samples. In addition, most biomolecules need to maintain their biological activity in a liquid environment, but water as polar substance has strong absorption to the THz wave. Thus, it is difficult to detect the sample information in aqueous solution using THz wave. In order to prevent the information of biological samples were masked in the solution, many research methods were used to explore how to reduce the water absorption of terahertz. In this paper, we have developed a real-time chemical methodology through transmission Terahertz time-domain spectroscopy (THz-TDS) system. The material of Zeonor 1020r is used as substrate and cover plate, and PDMS as channel interlayer. The transmission of the empty microfluidic chip is more than 80% in the range of 0.2-2.6 THz by THz-TDS system. Then, experiments were carried out using chips, which were filled with different volumes of 1, 2- propanediol, and it has been proved that the microfluidic chip could reduce the water absorption of terahertz. Finally, in order to further explore the reduction of terahertz to water absorption, we inject different concentrations of electrolyte to the chip. The results show that with the addition of different electrolytes, terahertz transmission line has evident changes. It can be taken into account that the electrolyte has different effects about the hydrogen bonds in the aqueous solution. Some of them can promote water molecules clusters, while others destroy them. Based on the basis of microfluidic chip, the discovery of this phenomenon can provide a way that reduces water absorption of terahertz. This work has laid a solid foundation for the subsequent study in reducing water absorption of terahertz.

  9. Integrated fiber optic incoherent broadband cavity enhanced absorption spectroscopy detector for near-IR absorption measurements of nanoliter samples.

    Science.gov (United States)

    Gomez, Anthony L; Renzi, Ronald F; Fruetel, Julia A; Bambha, Ray P

    2012-05-10

    An integrated fiber-optic sensor is described that uses incoherent broadband cavity enhanced absorption spectroscopy for sensitive detection of aqueous samples in nanoliter volumes. Absorption was measured in a 100 µm gap between the ends of two short segments of multimode graded-index fiber that were integrated into a capillary using a precision machined V-grooved fixture that allowed for passive fiber alignment. The other ends of the fibers were coated with dielectric mirrors to form a 9.5 cm optical resonator. Light from a fiber-coupled superluminescent diode was directly coupled into one end of the cavity, and transmission was measured using a fiber-coupled silicon photodiode. Dilute aqueous solutions of near infrared dye were used to determine the minimum detectable absorption change of 2.4×10(-4) under experimental conditions in which pressure fluctuations limited performance. We also determined that the absolute minimum detectable absorption change would be 1.6×10(-5) for conditions of constant pressure in which absorption measurement is limited by electronic and optical noise. Tolerance requirements for alignment are also presented.

  10. A mid-infrared absorption diagnostic for acetylene detection

    Science.gov (United States)

    KC, Utsav; Nasir, Ehson F.; Farooq, Aamir

    2015-08-01

    Acetylene is an important combustion intermediate and plays a critical role in soot formation. Accurate measurements of trace concentrations of acetylene can be very useful in validating hydrocarbon oxidation and soot formation mechanisms. Strongest vibrational band of acetylene near 13.7 μm is probed here to develop a highly sensitive absorption diagnostic. Experiments are carried out behind reflected shock waves to measure absorption cross sections of acetylene near 730 cm-1 over a wide range of temperatures (1000-2200 K) and pressures (1-5 bar). The diagnostic is demonstrated by measuring acetylene formation during the shock-heated pyrolysis and oxidation of propene.

  11. Estimation of the Human Absorption Cross Section Via Reverberation Models

    DEFF Research Database (Denmark)

    Steinböck, Gerhard; Pedersen, Troels; Fleury, Bernard Henri

    2018-01-01

    Since the presence of persons affects the reverberation time observed for in-room channels, the absorption cross section of a person can be estimated from measurements via Sabine's and Eyring's models for the reverberation time. We propose an estimator relying on the more accurate model by Eyring...... in the literature. We also suggest the use of controlled environments with low average absorption coefficients to obtain more reliable estimates. The obtained values can be used to predict the change of reverberation time with persons in the propagation environment. This allows prediction of channel characteristics...

  12. Heterocyclic methacrylates for clinical applications. III. Water absorption characteristics.

    Science.gov (United States)

    Patel, M P; Braden, M

    1991-09-01

    The water absorption and desorption behaviour of poly(isobornyl methacrylate) and poly(tetrahydropyran-2-ylmethyl methacrylate) obeyed diffusion laws on repeated absorption/desorption cycles. However, the polymers of 2,3-epoxypropyl, tetrahydrofurfuryl and tetrahydropyranyl methacrylates did not obey diffusion laws, did not equilibrate after 2 yr immersion in water and exhibited very high uptake values (30-90%). For 2,3-epoxypropyl methacrylate, the sample disintegrated. A clearly detailed structure of the heterocyclic ring is critical. The use of these monomers in room temperature polymerizing poly(ethyl methacrylate)/monomer systems generally reflected the behaviour of the related homopolymers.

  13. Theoretical assessment of sound absorption coefficient for anisotropic nonwovens

    Directory of Open Access Journals (Sweden)

    Klara Kalinova

    2012-03-01

    Full Text Available The anisotropy factor as a function of fiber arrangement, fiber fineness and sample thickness has been derived from the theories of soundwave transformation due to phase changing. The sound absorption coefficient of the anisotropic fibrous material is then theoretically calculated. The fibrous materials were prepared so that the fibers are arranged parallel (perpendicularly laid fiber web called STRUTO technology in the direction of soundwave propagation or perpendicularly (longitudinally laid fiber web to the direction of sound propagation. The sound absorption coefficient was measured due to the Impedance tube. The theoretical results are in good agreement with experimental findings.

  14. Absorptive effects in the diffractive dissociation of nucleons

    CERN Document Server

    Berger, E L

    1975-01-01

    Absorptive effects are found to be important in diffraction dissociation. For pp to (n pi /sup +/)p and np to (p pi /sup -/)p, at small excitation mass, a significant dip structure is created in the production momentum transfer distribution d sigma /dtdM near t=-0.3 (GeV/c)/sup 2/, in agreement with data from Fermilab and the CERN-ISR. The mass-slope correlation, seen in the data, is also reproduced. Most other distributions are affected much less by absorption. (13 refs).

  15. Solar absorption by Mie resonances in cloud droplets

    OpenAIRE

    Charles S. Zender; Talamantes, Jorge

    2006-01-01

    Recent studies suggest that resonant absorption of sunlight by cloud droplets may constitute a significant and unaccounted-for solar energy sink in the atmosphere. We spectrally resolve, for the first time, all solar absorption, including sharp resonances, in typical liquid water clouds. Resolving all sharp resonances requires a resolution in size parameter χ=2π r/λ (r—droplet radius, λ—incident wavelength) of about 10-7. The canonical integration resolution Δχ≈10-1 produces absor...

  16. The effect of cholestyramine and activated charcoal on glipizide absorption.

    OpenAIRE

    Kivistö, K T; Neuvonen, P J

    1990-01-01

    1. The interference of cholestyramine and activated charcoal with the absorption of glipizide was studied. 2. In a cross-over study comprising three phases, single doses of cholestyramine (8 g), activated charcoal (8 g) or water only were given to six healthy volunteers together with a single dose of glipizide. 3. The absorption of glipizide was moderately (29%, P less than 0.01) reduced by cholestyramine and greatly reduced (81%, P less than 0.01) by activated charcoal. 4. If cholestyramine ...

  17. Optical absorption of hyperbolic metamaterial with stochastic surfaces

    DEFF Research Database (Denmark)

    Liu, Jingjing; Naik, Gururaj V.; Ishii, Satoshi

    2014-01-01

    We investigate the absorption properties of planar hyperbolic metamaterials (HMMs) consisting of metal-dielectric multilayers, which support propagating plane waves with anomalously large wavevectors and high photonic-density-of-states over a broad bandwidth. An interface formed by depositing...... indium-tin-oxide nanoparticles on an HMM surface scatters light into the high-k propagating modes of the metamaterial and reduces reflection. We compare the reflection and absorption from an HMM with the nanoparticle cover layer versus those of a metal film with the same thickness also covered...

  18. Preparation and electromagnetic wave absorption of RGO/Cu nanocomposite

    Science.gov (United States)

    Zhang, Hui; Tian, Xingyou; Zhang, Xian; Li, Shikuo; Shen, Yuhua; Xie, Anjian

    2017-09-01

    We use a facile pyrolysis method to prepare reduced graphene oxide and copper nanocomposite (RGO/Cu) based on it. The product shows an outstanding wave absorption properties. The maximum reflection loss is up to-50.7 dB at 3.8 GHz. The reflection loss of-10 dB (90% power absorption) corresponds to a bandwidth of 11.2 GHz (3.4-14.6 GHz range) for the layer thickness of 2-5 mm. Therefore, it is suggested that the RGO/Cu nanocomposite is also a new kind of lightweight and high-performance EM wave absorbing material.

  19. A platform for colorful solar cells with enhanced absorption

    Science.gov (United States)

    Dhindsa, Navneet; Walia, Jaspreet; Singh Saini, Simarjeet

    2016-12-01

    We demonstrate submicron thick platform integrating amorphous silicon nanowires and thin-films achieving vivid colors in transmission and reflection. The platform nearly doubles the absorption efficiency compared to the starting thin-film without much compromising with color diverseness. The structural colors can be changed over a wide range by changing the diameters of the nanowires while still keeping the absorption efficiency higher than starting thin-film. The optical response of the platform is conceptually understood for different diameters combined with different thin-film thicknesses indicating the presence of leaky waveguide modes and coupled cavity modes. Our proposed platform can enable architectural low price colorful solar cells on transparent substrates.

  20. Extraordinary absorption of sound in porous lamella-crystals

    DEFF Research Database (Denmark)

    Christensen, Johan; Romero-García, V.; Picó, R.

    2014-01-01

    . Experimental measurements show that strong all-angle sound absorption with almost zero reflectance takes place for a frequency range exceeding two octaves. We demonstrate that lowering the crystal filling fraction increases the wave interaction time and is responsible for the enhancement of intrinsic material......We present the design of a structured material supporting complete absorption of sound with a broadband response and functional for any direction of incident radiation. The structure which is fabricated out of porous lamellas is arranged into a low-density crystal and backed by a reflecting support...

  1. Absorption of infrared radiation by human dental hard substances

    Science.gov (United States)

    Roth, Klaus K.; Duczynski, Edwin W.; von der Heide, Hans-Joachim; Struve, Bert

    1993-12-01

    Absorption spectra of enamel, dentin, synthetic hydroxyapatite and deionized water were taken in the wavelength band 500 to 3000 nm. It could be shown that infrared radiation is mainly absorbed in the aqueous components of dental hard tissues. Because of their decreased water content extinctions measured are slightly lower than those of deionized water. Furthermore, mineral absorptions could be detected in the range of 2760 to 2840 nm with a maximum at 2800 nm in enamel and a smaller one at 2500 nm in dentin.

  2. Absorption by Isolated Ferric Heme Nitrosyl Cations In Vacuo

    DEFF Research Database (Denmark)

    Wyer, Jean; Nielsen, Steen Brøndsted

    2012-01-01

    Keywords:biophysics;gas-phase spectroscopy;heme proteins;mass spectrometry;nitric oxide Almost innocent: In photobiophysical studies of ferric heme nitrosyl complexes, the absorption spectra of six-coordinate complexes with NO and Met or Cys are similar to that of the five-coordinate complex ion ......(heme)(NO)+. Since the absorption spectra of related proteins with histidine as the proximal ligand are similar to those of the gaseous complexes, the protein microenvironment has little effect on the lowest-energy transition of the porphyrin macrocycle....

  3. Comparison of absorption after inhalation and installation of uranium octoxide

    Energy Technology Data Exchange (ETDEWEB)

    Pellow, P.G.D.; Hodgson, S.A.; Hodgson, A.; Rance, E.; Ellender, M.; Guilmette, R.A.; Stradling, G.N

    2003-07-01

    Values for the absorption parameters were compared after inhalation or intratracheal installation of 1.5 {mu}m mass median aerodynamic diameter (MMAD) {sup 233}U{sub 3}O{sub 8} particles into the lungs of HMT strain rats. The two sets of parameter values were similar, as were the calculated dose coefficients and predicted biokinetics for workers. Hence the inhalation and installation techniques can probably both be used to generate values of the absorption parameters for U{sub 3}O{sub 8}. (author)

  4. COSTING A HOSPITAL SERVICE PRODUCT: MARGINAL Vs ABSORPTION COSTING.

    Science.gov (United States)

    Gupta, P K; Parmar, N K

    2001-07-01

    Costing a service product is a challenging but important tool for cost control. Different methods used for costing may provide varying costs and the choice of the method used becomes important. Use of absorption costing and marginal costing method and treatment of labour cost as variable and fixed cost provided different results in the present study of the cost of below knee patellar tendon bearing prosthesis. The study shows that marginal costing should also be done along with the absorption cost as it provides better indicator for cost control.

  5. Recent progress in GeSi electro-absorption modulators

    Directory of Open Access Journals (Sweden)

    Papichaya Chaisakul

    2014-01-01

    Full Text Available Electro-absorption from GeSi heterostructures is receiving growing attention as a high performance optical modulator for short distance optical interconnects. Ge incorporation with Si allows strong modulation mechanism using the Franz–Keldysh effect and the quantum-confined Stark effect from bulk and quantum well structures at telecommunication wavelengths. In this review, we discuss the current state of knowledge and the on-going challenges concerning the development of high performance GeSi electro-absorption modulators. We also provide feasible future prospects concerning this research topic.

  6. Time evolution of absorption process in nonlinear metallic photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Mahi R.; Hatef, Ali [Department of Physics and Astronomy, University of Western Ontario, London (Canada)

    2009-05-15

    The time evolution of the absorption coefficient in metallic photonic crystals has been studied numerically. These crystals are made from metallic spheres which are arranged periodically in air. The refractive index of the metallic spheres depends on the plasma frequency. Probe and pump fields are applied to monitor the absorption process. Ensembles of three-level particles are embedded in the crystal. Nanoparticles are interacting with the metallic crystals via the electron-photon interaction. It is found that when the resonance states lie away from the band edges system goes to transparent state. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Absorption and scattering of light by small particles

    CERN Document Server

    Bohren, Craig F

    1983-01-01

    Absorption and Scattering of Light by Small Particles. Treating absorption and scattering in equal measure, this self-contained, interdisciplinary study examines and illustrates how small particles absorb and scatter light. The authors emphasize that any discussion of the optical behavior of small particles is inseparable from a full understanding of the optical behavior of the parent material-bulk matter. To divorce one concept from the other is to render any study on scattering theory seriously incomplete. Special features and important topics covered in this book include:. * Classical theor

  8. Efficient absorption of visible radiation by gap plasmon resonators.

    Science.gov (United States)

    Nielsen, Michael G; Pors, Anders; Albrektsen, Ole; Bozhevolnyi, Sergey I

    2012-06-04

    We demonstrate experimentally a periodic array of differently-sized and circularly-shaped gap plasmon resonators (GPRs) with the average absorption ~94% for unpolarized light in the entire visible wavelength range (400-750 nm). Finite-element simulations verify that the polarization insensitive broadband absorption originates from localized gap surface plasmons whose resonant excitations only weakly depend on the angle of incidence. Arrays of GPRs also exhibit enhanced local field intensities (~115) as revealed by scanning two-photon photoluminescence microscopy, that are spectrally correlated with the minima in corresponding linear reflection spectra.

  9. Model systems for understanding absorption tuning by opsin proteins

    DEFF Research Database (Denmark)

    Nielsen, Mogens Brøndsted

    2009-01-01

    This tutorial review reports on model systems that have been synthesised and investigated for elucidating how opsin proteins tune the absorption of the protonated retinal Schiff base chromophore. In particular, the importance of the counteranion is highlighted. In addition, the review advocates...... for redefining the opsin shift, using the intrinsic absorption maximum (610 nm) of the protonated retinal Schiff base as a reference value, obtained by gas phase investigations, rather than the corresponding solvent value (441 nm). Hereby the necessity of correcting for solvent and counteranion effects...

  10. Reverse saturable absorption (RSA) in fluorinated iridium derivatives

    Science.gov (United States)

    Ferry, Michael J.; O'Donnell, Ryan M.; Bambha, Neal; Ensley, Trenton R.; Shensky, William M.; Shi, Jianmin

    2017-08-01

    The photophysical properties of cyclometallated iridium compounds are beneficial for nonlinear optical (NLO) applications, such as the design of reverse saturable absorption (RSA) materials. We report on the NLO characterization of a family of compounds of the form [Ir(pbt)2(LX)], where pbt is 2-phenylbenzothiazole and LX is a beta-diketonate ligand. In particular, we investigate the effects of trifluoromethylation on compound solubility and photophysics compared to the parent acetylacetonate (acac) version. The NLO properties, such as the singlet and triplet excited-state cross sections, of these compounds were measured using the Z-scan technique. The excited-state lifetimes were determined from visible transient absorption spectroscopy.

  11. Absorption of a laser light pulse in a dense plasma.

    Science.gov (United States)

    Mehlman-Balloffet, G.

    1973-01-01

    An experimental study of the absorption of a laser light pulse in a transient, high-density, high-temperature plasma is presented. The plasma is generated around a metallic anode tip by a fast capacitive discharge occurring in vacuum. The amount of transmitted light is measured for plasmas made of different metallic ions in the regions of the discharge of high electronic density. Variation of the transmission during the laser pulse is also recorded. Plasma electrons are considered responsible for the very high absorption observed.

  12. Absorption in Sport: A Cross-Validation Study

    Directory of Open Access Journals (Sweden)

    Stefan Koehn

    2017-08-01

    Full Text Available Absorption has been identified as readiness for experiences of deep involvement in the task. Conceptually, absorption is a key psychological construct, incorporating experiential, cognitive, and motivational components. Although, no operationalization of the construct has been provided to facilitate research in this area, the purpose of this research was the development and examination of the psychometric properties of a sport-specific measure of absorption that evolved from the use of the modified Tellegen Absorption Scale (MODTAS; Jamieson, 2005 in mainstream psychology. The study aimed to provide evidence of the psychometric properties, reliability, and validity of the Measure of Absorption in Sport Contexts (MASCs. The psychometric examination included a calibration sample from Scotland and a cross-validation sample from Australia using a cross-sectional design. The item pool was developed based on existing items from the modified Tellegen Absorption Scale (Jamieson, 2005. The MODTAS items were reworded and translated into a sport context. The Scottish sample consisted of 292 participants and the Australian sample of 314 participants. Congeneric model testing and confirmatory factor analysis for both samples and multi-group invariance testing across samples was used. In the cross-validation sample the MASC subscales showed acceptable internal consistency and construct reliability (≥0.70. Excellent fit indices were found for the final 18-item, six-factor measure in the cross-validation sample, χ(1202 = 197.486, p < 0.001; CFI = 0.957; TLI = 0.945; RMSEA = 0.045; SRMR = 0.044. Multi-group invariance testing revealed no differences in item meaning, except for two items. The MASC and the Dispositional Flow Scale-2 showed moderate-to-strong positive correlations in both samples, r = 0.38, p < 0.001 and r = 0.42, p < 0.001, supporting the external validity of the MASC. This article provides initial evidence in support of the psychometric

  13. An early nineteenth century absorption-based theory of mesmerism.

    Science.gov (United States)

    Gravitz, Melvin A

    2006-07-01

    In 1844, an obscure and little-remembered American theorist, A. Yorke (no further identification is available), published a theory of mesmerism based on absorption, i.e., mental concentration. Unlike Mesmer's conceptualization of animal magnetism as a biological fluid, however, Yorke's theory emphasized the psychological importance of the mutual interaction between mesmerist and subject. This paper discusses the latter's theory of absorption as an important development in neo-mesmerism, the circumstances that led him to his conclusions, and his role in advancing our knowledge of the historical origins of modern hypnosis.

  14. Zinc absorption from milk is affected by dilution but not by thermal processing, and milk enhances absorption of Zinc from high-phytate rice in young dutch women

    NARCIS (Netherlands)

    Talsma, Elise F.; Moretti, Diego; Ly, Sou Chheng; Dekkers, Renske; Heuvel, van den Ellen G.H.M.; Fitri, Aditia; Boelsma, Esther; Stomph, Tjeerd Jan; Zeder, Christophe; Melse-Boonstra, Alida

    2017-01-01

    Background: Milk has been suggested to increase zinc absorption. The effect of processing and the ability of milk to enhance zinc absorption from other foods has not been measured directly in humans. Objective: We aimed to assess zinc absorption from 1) milk undergoing various processing and

  15. Contrasting ERP absorption between transition and developed economies from Central and Eastern Europe (CEE)

    DEFF Research Database (Denmark)

    Bernroider, Edward W.N.; Sudzina, Frantisek; Pucihar, Andreja

    2011-01-01

    This article investigates Enterprise Resource Planning absorption in transition and developed economies in Central and Eastern Europe. Using absorptive capacity theory and data envelopment analysis, we view organizational transformation in Enterprise Resource Planning absorption as an economic...... production process. Despite converging Enterprise Resource Planning saturation levels, the data identifies gaps in absorption levels and performance. Organizations in transition face greater challenges, engage more in phased Enterprise Resource Planning absorptions, and expect higher levels of external...

  16. Experimental Characterization of Near-Infrared Laser Energy Absorption, Scattering, and Transmittance in Biological Tissue

    Science.gov (United States)

    2007-03-01

    upon incident radiation is absorption. Absorption is the process in which radiant energy is absorbed or taken up by a substance. General absorption...absorption. During absorption, the attenuation of the beam results in a transfer of energy to the tissue which is sometimes detected as heat, fluorescence ...water and tissue chromophores that include certain cellular pigments . The natural chromophores present include the biological pigments — specifically

  17. In silico predictions of gastrointestinal drug absorption in pharmaceutical product development: application of the mechanistic absorption model GI-Sim.

    Science.gov (United States)

    Sjögren, Erik; Westergren, Jan; Grant, Iain; Hanisch, Gunilla; Lindfors, Lennart; Lennernäs, Hans; Abrahamsson, Bertil; Tannergren, Christer

    2013-07-16

    Oral drug delivery is the predominant administration route for a major part of the pharmaceutical products used worldwide. Further understanding and improvement of gastrointestinal drug absorption predictions is currently a highly prioritized area of research within the pharmaceutical industry. The fraction absorbed (fabs) of an oral dose after administration of a solid dosage form is a key parameter in the estimation of the in vivo performance of an orally administrated drug formulation. This study discloses an evaluation of the predictive performance of the mechanistic physiologically based absorption model GI-Sim. GI-Sim deploys a compartmental gastrointestinal absorption and transit model as well as algorithms describing permeability, dissolution rate, salt effects, partitioning into micelles, particle and micelle drifting in the aqueous boundary layer, particle growth and amorphous or crystalline precipitation. Twelve APIs with reported or expected absorption limitations in humans, due to permeability, dissolution and/or solubility, were investigated. Predictions of the intestinal absorption for different doses and formulations were performed based on physicochemical and biopharmaceutical properties, such as solubility in buffer and simulated intestinal fluid, molecular weight, pK(a), diffusivity and molecule density, measured or estimated human effective permeability and particle size distribution. The performance of GI-Sim was evaluated by comparing predicted plasma concentration-time profiles along with oral pharmacokinetic parameters originating from clinical studies in healthy individuals. The capability of GI-Sim to correctly predict impact of dose and particle size as well as the in vivo performance of nanoformulations was also investigated. The overall predictive performance of GI-Sim was good as >95% of the predicted pharmacokinetic parameters (C(max) and AUC) were within a 2-fold deviation from the clinical observations and the predicted plasma AUC

  18. Gripped by movies: From story-world to artifact absorption

    NARCIS (Netherlands)

    Doicaru, M.M.

    2016-01-01

    That movies are a great source of entertainment seems to be common sense. But how exactly movies manage to get large audiences absorbed, or what is their gripping tool is still a mystery. Research makes use of different concepts pointing to narrative absorption, but it is not clear how they differ

  19. Rate of absorption and interfacial area of chlorine into aqueous ...

    African Journals Online (AJOL)

    aghomotsegin

    The rate of absorption predicted from developed model is compared with experimental results. They were in good agreement. ... are chlorine-water, chlorine-aqueous solution of alkaline carbonate, chlorine-aqueous alkaline ... Bulk concentration of an individual chemical species in liquid. Assuming all the reactions are at ...

  20. Two-Photon Coherent Atomic Absorption of Multiple Laser Beams

    Science.gov (United States)

    Li, Ming-Chiang

    2006-05-01

    Physical processes on two-photon coherent atomic absorption of multiple laser beams were discussed about thirty years ago [M. C. Li, Bull. Am. Phys. Soc. 20, 654 (1975)]. These processes can be divided into two distinct groups. In the first group, laser beams are from a single source, and in the second group laser beams are from two different sources [M. C. Li, Phys. Rev. A 22 (1980) 1323]. Several experiments in the first group were carried out and have led to the 2005 Nobel Prize in physics. The second group is more interesting. Beside atoms are in random motion, two photons are from different sources. Classically, it is impossible for atoms to transit coherently in the absorption process, but quantum mechanically, such a transition is possible and that is one of the spooky phenomena in quantum mechanic. To assure the coherent transition, each photon as absorbed by the atom must have two possible paths of choices. If one photon has the choice and other one is not, then the atomic transitions cannot be coherent. Around1990, there were very active experimental pursuits on such a spooky phenomenon of two photons emitted from crystal parametric down conversion. The present talk will review various spooky phenomena associated with two-photon coherent atomic absorption. Hope that the talk will stimulate the interest on the long neglected experimental front on two-photon coherent atomic absorption from two different laser sources.

  1. Rate of absorption and interfacial area of chlorine into aqueous ...

    African Journals Online (AJOL)

    Due to excellent mass transfer characteristics with energy efficiency jet ejectors can be used in place of conventional countercurrent systems, namely, packed bed contactors as well as venturi scrubbers, cyclones and airlift pumps. The removal of chlorine from certain gases by absorption in aqueous solutions of sodium ...

  2. Diagnostic potential of cosmic-neutrino absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Barenboim, Gabriela; /Valencia U.; Mena Requejo, Olga; Quigg, Chris; /Fermilab

    2004-12-01

    Annihilation of extremely energetic cosmic neutrinos on the relic-neutrino background can give rise to absorption lines at energies corresponding to formation of the electroweak gauge boson Z{sup 0}. The positions of the absorption dips are set by the masses of the relic neutrinos. Suitably intense sources of extremely energetic (10{sup 21} - 10{sup 25}-eV) cosmic neutrinos might therefore enable the determination of the absolute neutrino masses and the flavor composition of the mass eigenstates. Several factors--other than neutrino mass and composition--distort the absorption lines, however. We analyze the influence of the time-evolution of the relic-neutrino density and the consequences of neutrino decay. We consider the sensitivity of the lineshape to the age and character of extremely energetic neutrino sources, and to the thermal history of the Universe, reflected in the expansion rate. We take into account Fermi motion arising from the thermal distribution of the relic-neutrino gas. We also note the implications of Dirac vs. Majorana relics, and briefly consider unconventional neutrino histories. We ask what kinds of external information would enhance the potential of cosmic-neutrino absorption spectroscopy, and estimate the sensitivity required to make the technique a reality.

  3. Absorption of Beta Particles in Different Materials: An Undergraduate Experiment

    Science.gov (United States)

    La Rocca, Paola; Riggi, Francesco

    2009-01-01

    The absorption of beta rays from a radioactive source in different materials was investigated by the use of a simple setup based on a Geiger counter and a set of absorber sheets. The number of electrons traversing the material was measured as a function of its thickness. Detailed GEANT simulations were carried out to reproduce the obtained…

  4. High sensitivity probe absorption technique for time-of-flight ...

    Indian Academy of Sciences (India)

    We report on a phase-sensitive probe absorption technique with high sensitivity, capable of detecting a few hundred ultra-cold atoms in flight in an observation time of a few milliseconds. The large signal-to-noise ratio achieved is sufficient for reliable measurements on low intensity beams of cold atoms. We demonstrate the ...

  5. The Impact on Wind Power Integration from Geothermal Absorption

    DEFF Research Database (Denmark)

    Østergaard, Poul Alberg

    2012-01-01

    and lowtemperature geothermal resources. The analyses have also demonstrated that the municipality will still rely heavily on surrounding areas for electric load balancing assistance. With a departure in a previously elaborated 100% renewable energy scenario, this paper investigates how absorption heat pumps (AHP...

  6. Protonation Reaction of Benzonitrile Radical Anion and Absorption of Product

    DEFF Research Database (Denmark)

    Holcman, Jerzy; Sehested, Knud

    1975-01-01

    The rate constant for the protonation of benzonitrile radical anions formed in pulse radiolysis of aqueous benzonitrile solutions is (3.5 ± 0.5)× 1010 dm3 mol–1 s–1. A new 270 nm absorption band is attributed to the protonated benzonitrile anion. The pK of the protonation reaction is determined...

  7. X-ray-absorption studies of organodisulfide redox polymeric electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Yang, X.Q.; Xue, K.H.; Lee, H.S.; McBreen, J. (Brookhaven National Laboratory, Upton, New York 11973 (United States)); Skotheim, T.A. (Moltech Corporation, Stony Brook, New York 11794-2275 (United States)); Lu, F. (CFFLS, University of Kentucky, Lexington, Kentucky 40506 (United States))

    1992-03-01

    We have measured the near-edge x-ray-absorption fine-structure (NEXAFS) spectra of the {ital K} edge of sulfur in organodisulfide redox polymeric electrodes in both charged and discharged states. The formation and scission of S-S bonding during the charge-discharge cycle were observed through NEXAFS spectroscopy.

  8. Hydrosoluble and solvatochromic naphthalene diimides with NIR absorption.

    Science.gov (United States)

    Doria, Filippo; Gallati, Caroline Marie; Freccero, Mauro

    2013-12-07

    Mimicking biochromophore anions containing phenolate moieties, eight conjugated naphthalene diimides (NDIs) have been synthesized in order to develop probes, displaying charge-transfer transitions affected by the nearby environment. NIR absorption of the resulting phenolates and their solvatochromic properties in both organic solvents and water are described.

  9. Kinematic Interpretation of the Centaurus A Absorption-Line System

    NARCIS (Netherlands)

    Eckart, A.; Wild, W.; Ageorges, N.

    The location of the gas responsible for the absorption-line system toward the nucleus of Centaurus A is a puzzle. It is generally accepted that the line features close to the systemic velocity originate in the disk. The redshifted line features in particular, however, are usually thought to be due

  10. Cholesterol Absorption and Synthesis in Vegetarians and Omnivores.

    Science.gov (United States)

    Lütjohann, Dieter; Meyer, Sven; von Bergmann, Klaus; Stellaard, Frans

    2018-02-10

    Vegetarian diets are considered health-promoting; however, a plasma cholesterol lowering effect is not always observed. We investigate the link between vegetarian-diet-induced alterations in cholesterol metabolism. We study male and female omnivores, lacto-ovo vegetarians, lacto vegetarians, and vegans. Cholesterol intake, absorption, and fecal sterol excretion are measured as well as plasma concentrations of cholesterol and noncholesterol sterols. These serve as markers for cholesterol absorption, synthesis, and catabolism. The biliary cholesterol secretion rate is estimated. Flux data are related to body weight. Individual vegetarian diet groups are statistically compared to the omnivore group. Lacto vegetarians absorb 44% less dietary cholesterol, synthesized 22% more cholesterol, and show no differences in plasma total and LDL cholesterol. Vegan subjects absorb 90% less dietary cholesterol, synthesized 35% more cholesterol, and have a similar plasma total cholesterol, but a 13% lower plasma LDL cholesterol. No diet-related differences in biliary cholesterol secretion and absorption are observed. Total cholesterol absorption is lower only in vegans. Total cholesterol input is similar under all vegetarian diets. Unaltered biliary cholesterol secretion and higher cholesterol synthesis blunt the lowered dietary cholesterol intake in vegetarians. LDL cholesterol is significantly lower only in vegans. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Infrared Evanescent-Absorption Spectroscopy with Chalcogenide Glass-Fibers

    OpenAIRE

    Sanghera, J S; Kung, F H; Pureza, P. C.; Nguyen, V Q; Miklos, R. E.; Aggarwal, I D

    1994-01-01

    We have used telluride glass fibers fabricated in house to measure the evanescent-absorption spectra of water, methanol, ethanol, isopropanol, acetone, ethanoic acid, hexane, and chloroform. Furthermore, detection limits of less than 2 vol. % solute were obtained for mixtures of water and methanol, ethanol, isopropanol, acetone, and ethanoic acid. Techniques to reduce the detection limits are discussed.

  12. Strength and water absorption characteristics of cement-bonded ...

    African Journals Online (AJOL)

    The rate of water absorption (< 25% after 24 hours) and the resultant thickness swelling (<1% after 24 hours) of the boards was relatively slow. It was concluded that the material could be used in bearing wall construction and as partitioning in bungalows and one- storey buildings in Nigeria. Journal of Civil Engineering ...

  13. Absorption-based quantum communication with NV centres

    Science.gov (United States)

    Scharfenberger, Burkhard; Kosaka, Hideo; Munro, William J.; Nemoto, Kae

    2015-10-01

    We propose a scheme for performing an entanglement-swapping operation within a quantum communications hub (a Bell like measurement) using an NV-centre’s | +/- 1> ≤ftrightarrow | {A}2> optical transition. This is based on the heralded absorption of a photon resonant with that transition. The quantum efficiency of a single photon absorption is low but can be improved by placing the NV centre inside a micro cavity to boost the interaction time and further by recycling the leaked photon back into the cavity after flipping its phase and/or polarization. Throughout this process, the NV is repeatedly monitored via a QND measurement that heralds whether or not the photon absorption has succeeded. Upon success we know a destructive Bell measurement has occurred between that photon and NV centre. Given low losses and high per-pass absorption probability, this scheme should allow the total success probability to approach unity. With long electron spin coherence times possible at low temperatures, this component could be useful within a memory-based quantum repeater or relay.

  14. A dynamic model of digestion and absorption in pigs

    DEFF Research Database (Denmark)

    Strathe, Anders Bjerring; Danfær, Allan Christian; Chwalibog, Andre

    2008-01-01

    The paper describes and evaluates the construction of a mathematical model to study the kinetics of digestion and absorption in growing pigs. The core of the model is based on a compartmental structure, which divides the gastro-intestinal tract into four anatomical segments: the stomach, two parts...

  15. Insights into Digestion and Absorption of Major Nutrients in Humans

    Science.gov (United States)

    Goodman, Barbara E.

    2010-01-01

    Nutrient digestion and absorption is necessary for the survival of living organisms and has evolved into the complex and specific task of the gastrointestinal (GI) system. While most people simply assume that their GI tract will work properly to use nutrients, provide energy, and release wastes, few nonscientists know the details about how various…

  16. Probability of pion absorption by. cap alpha. -cluster in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Hachenberg, F. (Heidelberg Univ. (Germany, F.R.). Inst. fuer Theoretische Physik; Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany, F.R.))

    1982-07-08

    A multistep direct reaction model with pickup is extended to describe the formation of tritons and /sup 3/He-particles in nucleon- and pion-induced precompound reactions. In the latter ones, those tritons not accounted for by pickup can be explained as primary ones from absorption by ..cap alpha..-clusters, for which a 10% probability is deduced.

  17. Effects of Omeprazole on Iron Absorption: Preliminary Study

    Directory of Open Access Journals (Sweden)

    Mahmut Yaşar Çeliker

    2013-09-01

    Full Text Available Objective: Increasing numbers of pediatric and adult patients are being treated with proton pump inhibitors (PPIs. PPIs are known to inhibit gastric acid secretion. Nonheme iron requires gastric acid for conversion to the ferrous form for absorption. Ninety percent of dietary and 100% of oral iron therapy is in the nonheme form. To the best of our knowledge, the effect of PPIs on iron absorption has not been studied in humans. Our study assessed the relationship between omeprazole therapy and iron absorption in healthy subjects. Materials and Methods: We recruited 9 healthy volunteers between June 2010 and March 2011. Subjects with chronic illness, anemia, or use of PPI therapy were excluded. Serum iron concentrations were measured 1, 2, and 3 h after the ingestion of iron (control group. The measurements were repeated on a subsequent visit after 4 daily oral administrations of omeprazole at a dose of 40 mg (treatment group. Results: One female and 8 male volunteers were enrolled in the study with a mean age of 33 years. There was no statistical difference detected between baseline, 1-h, 2-h, and 3-h iron levels between control and treatment groups. Conclusion: Administration of omeprazole for a short duration does not affect absorption of orally administered iron in healthy individuals.

  18. The electron cyclotron absorption diagnostic at the Rijnhuizen tokamak project

    NARCIS (Netherlands)

    van Gelder, J. F. M.; Miedema, H. S.; Donne, A. J. H.; Oomens, A. A. M.; Schüller, F. C.

    1997-01-01

    A new 20-channel electron cyclotron absorption diagnostic has been developed at the Rijnhuizen tokamak project. It is the first time the electron pressure profile in a tokamak plasma can be measured directly with a time resolution of 1 ms. The diagnostic measures simultaneously the emission and

  19. Study of coupled heat and mass transfer during absorption of ...

    Indian Academy of Sciences (India)

    Performance studies on MmNi4·6Al0·4 based hydrogen storage device are carried out by varying the hydrogen supply pressure, absorption (cooling fluid) temperature, overall heat transfer coefficient and hydride bed thickness. Effect of convection terms in the energy equation on hydrogen storage performance is found to ...

  20. Slow-light enhancement of Beer-Lambert-Bouguer absorption

    Science.gov (United States)

    Mortensen, Niels Asger; Xiao, Sanshui

    2007-04-01

    The authors theoretically show how slow light in an optofluidic environment facilitates enhanced light-matter interactions, by orders of magnitude. The proposed concept provides strong opportunities for improving existing miniaturized chemical absorbance cells for Beer-Lambert-Bouguer absorption measurements widely employed in analytical chemistry.

  1. Silver Nanoparticles with Broad Multiband Linear Optical Absorption

    KAUST Repository

    Bakr, Osman M.

    2009-07-06

    A simple one-pot method produces silver nanoparticles coated with aryl thiols that show intense, broad nonplasmonic optical properties. The synthesis works with many aryl-thiol capping ligands, including water-soluble 4-mercaptobenzoic acid. The nanoparticles produced show linear absorption that is broader, stronger, and more structured than most conventional organic and inorganic dyes.

  2. The effect of stress on absorption of acetaminophen.

    Science.gov (United States)

    Flaten, Magne Arve; Asli, Ole; Simonsen, Terje

    2006-05-01

    There is a large variability in the response to pharmacological treatment. Some studies have linked this variability to stress levels, i.e., stress may slow and/or reduce absorption of drugs. The present experiment investigated the hypothesis that stress slows absorption of drugs. Twenty-four volunteers participated in a within-subjects design with three conditions, each lasting 70 min. Subjects watched a movie hypothesized to induce stress, subjects listened to music hypothesized to reduce stress, and in a control condition no stimuli were presented. Each condition was spaced 2 days or more apart. In each condition, subjects received 500 mg oral acetaminophen. Measures of stress and acetaminophen levels were obtained every 10 min. Indices of subjective stress and arousal and cortisol, were increased during the movie compared to control. Subjective arousal and cortisol were decreased during music compared to control. However, acetaminophen levels were the same across time in all three experimental conditions. There was no effect of the experimental manipulations on acetaminophen absorption, indicating that stress was not related to drug absorption. However, stress could play a role in other processes related to drug pharmacokinetics.

  3. Permeabilization of enterocytes induced by absorption of dietary fat

    DEFF Research Database (Denmark)

    Danielsen, Erik Michael; Hansen, Gert H; Rasmussen, Karina

    2013-01-01

    penetrated the epithelium and accumulated in the basal lamina and the lamina propria. LY was also seen in the paracellular space, whereas villus enterocytes were generally only weakly labeled except for small amounts taken up by apical endocytosis. In the crypts, however, fat absorption induced cell...

  4. Redox ratio and optical absorption of polyvalent ions in industrial ...

    Indian Academy of Sciences (India)

    WINTEC

    Redox ratio and optical absorption of polyvalent ions in industrial glasses. W THIEMSORN*, K KEOWKAMNERD, P SUWANNATHADA, H HESSENKEMPER. † and. S PHANICHAPHANT. Faculty of Science, Chiang Mai University, Chiang Mai 50202, Thailand. †Institute of Ceramics, Glass and Cement, Freiberg University of ...

  5. Effects of flavour absorption on foods and their packaging materials

    NARCIS (Netherlands)

    Willige, van R.W.G.

    2002-01-01

    Keywords: flavour absorption, scalping, packaging, food matrix, lldpe, ldpe, pp, pc, pet, pen,b-lactoglobulin, casein, pectin, cmc, lactose, saccharose, oil, modelling, storage, oxygen permeability, taste perception,

  6. Gas absorption studies in a butterfly valve scrubber

    Energy Technology Data Exchange (ETDEWEB)

    Beg, S.A.; Taheri, M.

    1974-09-01

    Gas absorption and pressure drop in a wetted butterfly valve constituting a novel scrubber system are investigated. The exceptional suitability of the butterfly device is demonstrated by its flexibility to adjust to large variations in both gas and liquid flow rates. (1 diagram, 5 graphs, 19 references)

  7. Dielectric Characteristics and Microwave Absorption of Graphene Composite Materials

    Directory of Open Access Journals (Sweden)

    Kevin Rubrice

    2016-10-01

    Full Text Available Nowadays, many types of materials are elaborated for microwave absorption applications. Carbon-based nanoparticles belong to these types of materials. Among these, graphene presents some distinctive features for electromagnetic radiation absorption and thus microwave isolation applications. In this paper, the dielectric characteristics and microwave absorption properties of epoxy resin loaded with graphene particles are presented from 2 GHz to 18 GHz. The influence of various parameters such as particle size (3 µm, 6–8 µm, and 15 µm and weight ratio (from 5% to 25% are presented, studied, and discussed. The sample loaded with the smallest graphene size (3 µm and the highest weight ratio (25% exhibits high loss tangent (tanδ = 0.36 and a middle dielectric constant ε′ = 12–14 in the 8–10 GHz frequency range. As expected, this sample also provides the highest absorption level: from 5 dB/cm at 4 GHz to 16 dB/cm at 18 GHz.

  8. Optical absorption and fluorescence properties of Er in sodium ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. Spectroscopic properties of Er3+ ions in sodium borate glass have been studied. The indirect and direct optical band gaps (Eopt) and energy level parameters (Racah (E1, E2 and E3), spin-orbit (ξ4f) and con- figurational interaction (α)) are evaluated. Spectral intensities for various absorption bands of Er3+ doped.

  9. UV-VIS absorption spectroscopy: Lambert-Beer reloaded

    Science.gov (United States)

    Mäntele, Werner; Deniz, Erhan

    2017-02-01

    UV-VIS absorption spectroscopy is used in almost every spectroscopy laboratory for routine analysis or research. All spectroscopists rely on the Lambert-Beer Law but many of them are less aware of its limitations. This tutorial discusses typical problems in routine spectroscopy that come along with technical limitations or careless selection of experimental parameters. Simple rules are provided to avoid these problems.

  10. The Effects of Viscosity and Radiation Absorption on Double ...

    African Journals Online (AJOL)

    This study is devoted to the problem of the effect of radiation absorption on the onset of thermosolutal convection in a horizontal fluid layer taking into consideration viscous effects when the fluid is heated from below in a horizontal porous layer. The radiative heat transfer is heated using the differential approximation for ...

  11. Physico - chemical chyme conditions and mineral absorption in broilers

    NARCIS (Netherlands)

    Klis, van der J.D.

    1993-01-01


    In the Netherlands the efficiency of mineral absorption from the gastrointestinal tract of farm animals is a topic of interest to reduce the mineral concentration in animal manure. This study was done with broilers. It was focused on physico-chemical chyme conditions. These

  12. determination of vanadium in foods by atomic absorption spectrometry

    African Journals Online (AJOL)

    This paper presents an assessment of the level of vanadium in foods (Plantain, Musa spp; Yam, Discorea rotundata; and Maize, Zea mays) from ten popular market places in Lagos metropolis, Nigeria. Total acid leaching digestion method was employed and determination was by Flame Atomic Absorption ...

  13. Broadening microwave absorption via a multi-domain structure

    Directory of Open Access Journals (Sweden)

    Zhengwang Liu

    2017-04-01

    Full Text Available Materials with a high saturation magnetization have gained increasing attention in the field of microwave absorption; therefore, the magnetization value depends on the magnetic configuration inside them. However, the broad-band absorption in the range of microwave frequency (2-18 GHz is a great challenge. Herein, the three-dimensional (3D Fe/C hollow microspheres are constructed by iron nanocrystals permeating inside carbon matrix with a saturation magnetization of 340 emu/g, which is 1.55 times as that of bulk Fe, unexpectedly. Electron tomography, electron holography, and Lorentz transmission electron microscopy imaging provide the powerful testimony about Fe/C interpenetration and multi-domain state constructed by vortex and stripe domains. Benefiting from the unique chemical and magnetic microstructures, the microwave minimum absorption is as strong as −55 dB and the bandwidth (<−10 dB spans 12.5 GHz ranging from 5.5 to 18 GHz. Morphology and distribution of magnetic nano-domains can be facilely regulated by a controllable reduction sintering under H2/Ar gas and an optimized temperature over 450–850 °C. The findings might shed new light on the synthesis strategies of the materials with the broad-band frequency and understanding the association between multi-domain coupling and microwave absorption performance.

  14. Fractional Diffusion in a Solid with Mass Absorption

    Directory of Open Access Journals (Sweden)

    Yuriy Povstenko

    2017-05-01

    Full Text Available The space-time-fractional diffusion equation with the Caputo time-fractional derivative and Riesz fractional Laplacian is considered in the case of axial symmetry. Mass absorption (mass release is described by a source term proportional to concentration. The integral transform technique is used. Different particular cases of the solution are studied. The numerical results are illustrated graphically.

  15. DECAB: process development of a phase change absorption process

    NARCIS (Netherlands)

    Sanchez Fernandez, E.; Goetheer, E.L.V.

    2011-01-01

    This work describes the conceptual design of a novel separation process for CO2 removal from flue gas based on precipitating solvents. The process here described (DECAB) is an enhanced CO2 absorption based on the Le Chatelier's principle, which states that reaction equilibrium can be shifted by

  16. Lifshitz tails for the interband light absorption coefficient

    Indian Academy of Sciences (India)

    In this paper we consider the interband light absorption coefficient (ILAC) for various models. We show that at the lower and upper edges of the spectrum the Lifshitz tails behaviour of the density of states implies similar behaviour for the ILAC at appropriate energies. The Lifshitz tails property is also exhibited at some points ...

  17. Isothermal absorption of soluble gases by atmospheric nanoaerosols.

    Science.gov (United States)

    Elperin, T; Fominykh, A; Krasovitov, B; Lushnikov, A

    2013-01-01

    We investigate mass transfer during the isothermal absorption of atmospheric trace soluble gases by a single droplet whose size is comparable to the molecular mean free path in air at normal conditions. It is assumed that the trace reactant diffuses to the droplet surface and then reacts with the substances inside the droplet according to the first-order rate law. Our analysis applies a flux-matching theory of transport processes in gases and assumes constant thermophysical properties of the gases and liquids. We derive an integral equation of Volterra type for the transient molecular flux density to a liquid droplet and solve it numerically. Numerical calculations are performed for absorption of sulfur dioxide (SO(2)), dinitrogen trioxide (N(2)O(3)), and chlorine (Cl(2)) by liquid nanoaerosols accompanied by chemical dissociation reaction. It is shown that during gas absorption by nanoaerosols, the kinetic effects play a significant role, and neglecting kinetic effects leads to a significant overestimation of the soluble gas flux into a droplet during the entire period of gas absorption.

  18. Synergistic Two-Photon Absorption Enhancement in Photosynthetic Light Harvesting

    Science.gov (United States)

    Chen, Kuo-Mei; Chen, Yu-Wei; Gao, Ting-Fong

    2012-06-01

    The grand scale fixation of solar energies into chemical substances by photosynthetic reactions of light-harvesting organisms provides Earth's other life forms a thriving environment. Scientific explorations in the past decades have unraveled the fundamental photophysical and photochemical processes in photosynthesis. Higher plants, green algae, and light-harvesting bacteria utilize organized pigment-protein complexes to harvest solar power efficiently and the resultant electronic excitations are funneled into a reaction center, where the first charge separation process takes place. Here we show experimental evidences that green algae (Chlorella vulgaris) in vivo display a synergistic two-photon absorption enhancement in their photosynthetic light harvesting. Their absorption coefficients at various wavelengths display dramatic dependence on the photon flux. This newly found phenomenon is attributed to a coherence-electronic-energy-transfer-mediated (CEETRAM) photon absorption process of light-harvesting pigment-protein complexes of green algae. Under the ambient light level, algae and higher plants can utilize this quantum mechanical mechanism to create two entangled electronic excitations adjacently in their light-harvesting networks. Concerted multiple electron transfer reactions in the reaction centers and oxygen evolving complexes can be implemented efficiently by the coherent motion of two entangled excitons from antennae to the charge separation reaction sites. To fabricate nanostructured, synthetic light-harvesting apparatus, the paramount role of the CEETRAM photon absorption mechanism should be seriously considered in the strategic guidelines.

  19. Synthesis and Characteristics of Highly Oil-absorptive Expanded Polyurethane

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y.H. [Pusan National University, Pusan (Korea); Kim, W. [Dong Ah Chem. Co. Ltd., Kyungnam (Korea); Kim, W.H. [Pusan National University, Pusan (Korea)

    2000-03-01

    Oil-absorptive expanded polyurethane (EPU) was prepared with a lypophilic polyol, polypropyleneglycol (PPG) as the soft segment, and toluenediisocyanate (TDI) and H{sub 2}O as the hard segment. PPGs having various average molecular weights (M{sub n} : 1000, 2000, 3000) were employed to investigate that the soft segment content was consequent on the oil-absorptivity and the mechanical properties of the EPUs. As M{sub n} of PPG was decreased from 3000 to 1000, the oil-absorptivity and the tensile strength of the EPUs increased from 1460 to 3010% and from 0.26 to 0.55 kg{sub f}/cm{sup 2} respectively. As the hard segment content ratio, {gamma}([NCO]/[OH]) was increased from 1.0 to 1.2, the tensile strength of the EPUs increased from 0.56 to 0.95 kg{sub f}/cm{sup 2}, due to the formation of allophanate and/or biuret bondings. However, as the surfactant (S-A) content was increased from 1.0 to 2.5 pbw, the oil-absorptivity was decreased from 3634 to 3312%, due to the formation of closed cell structures. (author). 18 refs., 4 tabs., 14 figs.

  20. THz Electro-absorption Effect in Quantum Dots

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Monozon, Boris S.; Livshits, Daniil A.

    2011-01-01

    In a THz pump - optical probe experiment we demonstrate an instantaneous electro-absorption effect in InGaAs/GaAs quantum dots, induced by the electric field of a single-cycle THz pulse with 3 THz bandwidth and with free-space peak electric field reaching 220 kV/cm. The transient modulation of QD...

  1. Calibrating a spatially encoded time delay for transient absorption spectroscopy

    Science.gov (United States)

    Wilson, Kelly S.; Wong, Cathy Y.

    2017-08-01

    A novel spectroscopy termed single shot transient absorption (SSTA) is presented that can collect a transient absorption spectrum in 6 ms by using laser pulses with tilted wavefronts to spatially encode the delay between pump and probe pulse arrival times at the sample. The transient absorption technique determines the change in sample transmission that results from sample photoexcitation, and tracks this change as a function of the time delay between the arrival of the pump pulse and the probe pulse. Typically, these time delays are generated using a retroreflecting mirror mounted on a motorized translation stage, with a measurement collected at each translation stage position. Because these measurements must be performed in series, data collection requires a significant amount of time. This limits transient absorption to the measurement of systems that are static for the duration of the experiment. SSTA overcomes this restriction by employing pump and probe pulses which are each focused into a line and tilted with respect to each other to spatially encode time delays within the sample. Here, we describe the SSTA technique and instrumentation, demonstrate the principle of this spectroscopy, and present a method for calibrating the spatially encoded time delay by autocorrelation. This instrument will broaden the scop

  2. Parametric analysis of a double-effect steam absorption chiller

    Science.gov (United States)

    Mohammed Salih Ahmed, Mojahid Sid Ahmed; Gilani, Syed Ihtsham Ul-Haq

    2012-06-01

    The development in the field of refrigeration and cooling systems based on absorption cycles has attained its own internal dynamic in the last decade. A major obstacle for developing model is the lack of available component specifications. These specifications are commonly proprietary of the chiller's manufacturers and normally the available information is not sufficient. This work presented a double-effect parallel-flow-type steam absorption chiller model based on thermodynamic and energy equations. The chiller studied is 1250 RT (Refrigeration Tons) using lithium bromide -water as working pair. The mathematical equations that govern the operation of the steam absorption chiller are developed, and from the available design data the values of the overall heat transfer coefficient multiplied by the heat exchanger surface area and the characteristics of each component of the absorption chiller at the design point are calculated. For thermo physical and thermodynamic properties for lithium bromide-water solution, set of computationally efficient formulations are used. The model gives the required information about temperature, concentration, and flow rate at each state point of the system. The model calculates the heat load at each component as well as the performance of the system.

  3. Rate of absorption and interfacial area of chlorine into aqueous ...

    African Journals Online (AJOL)

    aghomotsegin

    chlorine in NaOH. Ashour et al. (1996) studied the absorption of Cl2 into aqueous bicarbonate and aqueous hydroxide solutions both experimentally and theoretically. They estimated the reaction rate coefficient of reaction between Cl2 and OH- over the temperature range of 293 to 312 K and fitted by the Arrhenius equation ...

  4. The Absorption of Nitrate and Phosphate from Urban Sewage by ...

    African Journals Online (AJOL)

    The applications of blue green algae for the treatment of urban and industrial sewage have received more attention during the recent years because they have the capacity to use nitrogenous compounds, ammonia and phosphates. In this study aimed to evaluate the ability of Spirolina platensis for absorption of nitrate and ...

  5. Effect of lutein on beta-carotene absorption and cleavage

    NARCIS (Netherlands)

    Berg, H. van den

    1998-01-01

    Carotenoid interactions during absorption anti in postabsorptive metabolism have been observed in both human and animal studies. We reviewed the mutual interactions reported between lutein and β-carotene and report new data on the postprandial β-carotene and retinyl ester response in the

  6. Influence of moisture absorption on the flexural properties of ...

    Indian Academy of Sciences (India)

    It was found that during the processof moisture absorption there exists a variation of the flexural properties closely related to the degradation of the mechanicalbehaviour of the composite, as well as the percentage amount of moisture absorbed. Experiments were carried out withcomposite made of epoxy resin reinforced ...

  7. Infrared absorption peaks in nitrogen doped CZ silicon

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, N. [RIAST, Osaka Prefecture University, Gakuen-cho, Sakai, Osaka 599-8570 (Japan); JEITA Nitrogen Measurement WG, 3-11 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan)]. E-mail: inouen@riast.osakafu-u.ac.jp; Nakatsu, M. [RIAST, Osaka Prefecture University, Gakuen-cho, Sakai, Osaka 599-8570 (Japan); Ono, H. [Japan Fine Ceramics Center, 2-4-3 Nishi-shinbashi, Minato-ku, Tokyo 105-0003 (Japan); JEITA Nitrogen Measurement WG, 3-11 Kanda-surugadai, Chiyoda-ku, Tokyo 101-0062 (Japan); Inoue, Y. [Tokyo University of Education, Bunkyo-ku, Tokyo 117-0002 (Japan)

    2006-10-15

    Dependences on annealing temperature and nitrogen concentration were examined for new local vibration mode infrared absorption peaks at 856, 973, 984 and 1002 cm{sup -1} in nitrogen-doped CZ silicon crystal. The new absorption peaks were so weak that two sets of samples were examined for temperature and concentration dependences, respectively, to get reliable results. The peak at 1002 cm{sup -1} behaved similarly for annealing, though much weaker, to the known peaks at 810 and 1018 cm{sup -1} which are attributed to interstitial N pair accompanied by the two oxygen interstitials (NNO {sub i}O {sub i}). This suggests that the origin contains 2 O {sub i} also. It was strong in low concentration regime, which is similar to the behavior of shallow thermal donors. This suggests that the structure contains one nitrogen rather than two (N-O interstitial pair). The results were compared with the electronic transition absorption by shallow thermal donors (STD). The absorptions at 1002 and 240 cm{sup -1} behaved similarly. These suggest that the peak at 1002 cm{sup -1} is likely due to NOO {sub i}O {sub i} which is the candidate for STD. The temperature dependence of the other new peaks was slightly different from each other. Origin of the other peaks is not clear yet.

  8. Developing a Transdisciplinary Teaching Implement for Atomic Absorption Spectroscopy

    Science.gov (United States)

    Drew, John

    2008-01-01

    In this article I explain why I wrote the set of teaching notes on Atomic Absorption Spectroscopy (AAS) and why they look the way they do. The notes were intended as a student reference to question, highlight and write over as much as they wish during an initial practical demonstration of the threshold concept being introduced, in this case…

  9. Atomic Absorption Spectroscopy. The Present and the Future.

    Science.gov (United States)

    Slavin, Walter

    1982-01-01

    The status of current techniques and methods of atomic absorption (AA) spectroscopy (flame, hybrid, and furnace AA) is discussed, including limitations. Technological opportunities and how they may be used in AA are also discussed, focusing on automation, microprocessors, continuum AA, hybrid analyses, and others. (Author/JN)

  10. Atomic Absorption, Atomic Fluorescence, and Flame Emission Spectrometry.

    Science.gov (United States)

    Horlick, Gary

    1984-01-01

    This review is presented in six sections. Sections focus on literature related to: (1) developments in instrumentation, measurement techniques, and procedures; (2) performance studies of flames and electrothermal atomizers; (3) applications of atomic absorption spectrometry; (4) analytical comparisons; (5) atomic fluorescence spectrometry; and (6)…

  11. Reliability of graphite furnace atomic absorption spectrometry as ...

    African Journals Online (AJOL)

    Original Research Article. Reliability of graphite furnace atomic absorption spectrometry as alternative method for trace analysis of arsenic in natural medicinal products. Reem Saadi Khalid1*, ABM Helaluddin1, Reem Saadi Khalid1, Mohamed. Alaama1, Abdualrahman M Abdualkader1, Abdulrazak Kasmuri2 and Syed Atif.

  12. combination of flame atomic absorption spectrometry with ligandless

    African Journals Online (AJOL)

    Preferred Customer

    separation and flame atomic absorption spectrometry determination of trace amount of lead(II) ion. In the proposed approach 1,2-dicholorobenzene and ethanol were used as extraction .... in ethanol was added to it. The final solution was aspirated directly into the flame of AAS. The extraction scheme of Pb(II) ion is shown in.

  13. Enhanced microwave-to-terahertz absorption in graphene

    Energy Technology Data Exchange (ETDEWEB)

    Batrakov, K., E-mail: kgbatrakov@gmail.com; Kuzhir, P.; Maksimenko, S.; Volynets, N.; Voronovich, S. [Research Institute for Nuclear Problems, Belarusian State University, Minsk 220030 (Belarus); Paddubskaya, A.; Valusis, G. [Center for Physical Sciences and Technology, A. Gostauto 11, Vilnius LT-01108 (Lithuania); Kaplas, T.; Svirko, Yu. [Institute of Photonics, University of Eastern Finland, Joensuu FI-80101 (Finland); Lambin, Ph. [Physics Department, Universite de Namur, 61 Rue de Bruxelles, B-5000 Namur (Belgium)

    2016-03-21

    Fresnel equations predict that an ultrathin free standing conductive film, thousands times thinner than skin depth, is capable to absorb up to 50% of incident electromagnetic radiations. In the microwave range, the same holds true for a free standing graphene sheet. We demonstrate theoretically and prove experimentally that microwave absorptance of graphene can be enhanced considerably by depositing graphene on a dielectric substrate. On the experimental side, we obtain 80% and 65% absorptance at 30 GHz and 1 THz, respectively. Theory predicts that higher absorptance can be achieved with a suitable choice of the dielectric permittivity and the thickness of the substrate. Absorption can also be maximized by choosing the optimum incidence angle for s-polarized waves in free space or by working in the vicinity of the cut-off frequency of the transverse electric mode in waveguide configuration. The polarization sensitivity of the transmittance and reflectance of graphene layers can be used to tune the polarization state of the transmitted and reflected radiations.

  14. Colloidal carriers for extended absorption window of furosemide.

    Science.gov (United States)

    Sultan, Amal A; El-Gizawy, Sanaa A; Osman, Mohamed A; El Maghraby, Gamal M

    2016-03-01

    The aim was to investigate the potential of self-microemulsifying drug delivery systems (SMEDDS) and niosomes as carriers for widening the gastrointestinal absorption window of furosemide (model acidic drug). The drug was incorporated in SMEDDS and was encapsulated into niosomes. The intestinal absorption was monitored at two anatomical sites (duodenum and jejuno-ileum). This employed in situ rabbit intestinal perfusion technique. Perfusion of drug solution (control) revealed poor intestinal permeability with per cent fraction absorbed (%Fa) from the duodenum and jejuno-ileum being 1.3 and 0.6 % per cm, respectively. Formulation of furosemide as SMEDDS increased the %Fa from the duodenum and jejuno-ileum to reach 1.7 and 1 % per cm, respectively. Niosomal encapsulation increased the %Fa from duodenum and jejuno-ileum to record 1.9 and 1.2 % per cm, respectively. The increase in the %Fa was also revealed as a reduction in the length required for 95 % absorption of the drug which was reduced from 557.2 to 245.8 cm and to 279.8 cm after delivery as niosomes or SMEDDS, respectively, in case of jejuno-ileum. The same trend was recorded with the duodenum. The recorded results highlighted the potential for SMEDDS and niosomes for widening the absorption window of acidic drugs after oral administration. © 2016 Royal Pharmaceutical Society, Journal of Pharmacy and Pharmacology.

  15. Maximum absorption by homogeneous magneto-dielectric sphere

    DEFF Research Database (Denmark)

    Palvig, Michael Forum; Breinbjerg, Olav; Willatzen, Morten

    2014-01-01

    n order to obtain a benchmark for electromagnetic energy harvesting, we investigate the maximum absorption efficiency by a magneto-dielectric homogeneous sphere illuminated by a plane wave, and we arrive at several novel results. For electrically small spheres we show that the optimal relative pe...

  16. Sub-millimetre wave absorption spectra of artificial RNA molecules

    CERN Document Server

    Globus, T; Woolard, D; Gelmont, B

    2003-01-01

    We demonstrate submillimetre-wave Fourier transform spectroscopy as a novel technique for biological molecule characterization. Transmission measurements are reported at frequencies 10-25 cm sup - sup 1 for single- and double-stranded RNA molecules of known base-pair sequences: homopolymers poly[A], poly[U], poly[C] and poly[G], and double-stranded homopolymers poly[A]-poly[U] and poly[C]-poly[G]. Multiple resonances are observed (i.e. in the microwave through terahertz frequency regime). We also present a computational method to predict the low-frequency absorption spectra of short artificial DNA and RNA. Theoretical conformational analysis of molecules was utilized to derive the low-frequency vibrational modes. Oscillator strengths were calculated for all the vibrational modes in order to evaluate their weight in the absorption spectrum of a molecule. Normal modes and absorption spectra of the double-stranded RNA chain poly[C]-poly[G] were calculated. The absorption spectra extracted from the experiment wer...

  17. improvement to the design of a solid absorption solar refrigerator

    African Journals Online (AJOL)

    user

    The paper presents the highlights of the design of an existing solid absorption solar refrigerator, using CaCl2 ... on the coupling of auxiliary heating systems to the solar powered refrigerator. A re-design of the ... Six collector tubes, having a perforated co-axial galvanised inner steel tube, were bonded to the plate at 152 mm.

  18. In situ sound absorption measurement: investigations on oblique incidence

    NARCIS (Netherlands)

    Kuipers, E.R.; Wijnant, Ysbrand H.; de Boer, Andries; Klemenz, M.

    2012-01-01

    A novel method for the measurement of sound absorption has been developed. By assuming that, in a single point, the sound field consists of an incident- and a reflected plane wave, the locally incident- and reflected intensities can be determined. To this purpose, the active intensity and the sum of

  19. In situ gas temperature measurements by UV-absorption spectroscopy

    DEFF Research Database (Denmark)

    Fateev, Alexander; Clausen, Sønnik

    2009-01-01

    The absorption spectrum of the NO A(2)Sigma(+) situ evaluation of gas temperature. Experiments were performed with a newly developed atmospheric-pressure high-temperature flow gas cell at highly uniform and stable gas temperatures over a 0.533 m path...

  20. Broadening microwave absorption via a multi-domain structure

    Science.gov (United States)

    Liu, Zhengwang; Che, Renchao; Wei, Yong; Liu, Yupu; Elzatahry, Ahmed A.; Dahyan, Daifallah Al.; Zhao, Dongyuan

    2017-04-01

    Materials with a high saturation magnetization have gained increasing attention in the field of microwave absorption; therefore, the magnetization value depends on the magnetic configuration inside them. However, the broad-band absorption in the range of microwave frequency (2-18 GHz) is a great challenge. Herein, the three-dimensional (3D) Fe/C hollow microspheres are constructed by iron nanocrystals permeating inside carbon matrix with a saturation magnetization of 340 emu/g, which is 1.55 times as that of bulk Fe, unexpectedly. Electron tomography, electron holography, and Lorentz transmission electron microscopy imaging provide the powerful testimony about Fe/C interpenetration and multi-domain state constructed by vortex and stripe domains. Benefiting from the unique chemical and magnetic microstructures, the microwave minimum absorption is as strong as -55 dB and the bandwidth (spans 12.5 GHz ranging from 5.5 to 18 GHz. Morphology and distribution of magnetic nano-domains can be facilely regulated by a controllable reduction sintering under H2/Ar gas and an optimized temperature over 450-850 °C. The findings might shed new light on the synthesis strategies of the materials with the broad-band frequency and understanding the association between multi-domain coupling and microwave absorption performance.