Science.gov

Sample records for diffraction based residual

  1. Method for improve x-ray diffraction determinations of residual stress in nickel-base alloys

    DOEpatents

    Berman, Robert M.; Cohen, Isadore

    1990-01-01

    A process for improving the technique of measuring residual stress by x-ray diffraction in pieces of nickel-base alloys which comprises covering part of a predetermined area of the surface of a nickel-base alloy with a dispersion, exposing the covered and uncovered portions of the surface of the alloy to x-rays by way of an x-ray diffractometry apparatus, making x-ray diffraction determinations of the exposed surface, and measuring the residual stress in the alloy based on these determinations. The dispersion is opaque to x-rays and serves a dual purpose since it masks off unsatisfactory signals such that only a small portion of the surface is measured, and it supplies an internal standard by providing diffractogram peaks comparable to the peaks of the nickel alloy so that the alloy peaks can be very accurately located regardless of any sources of error external to the sample.

  2. Method for improving x-ray diffraction determinations of residual stress in nickel-base alloys

    DOEpatents

    Berman, R.M.; Cohen, I.

    1988-04-26

    A process for improving the technique of measuring residual stress by x-ray diffraction in pieces of nickel-base alloys is discussed. Part of a predetermined area of the surface of a nickel-base alloy is covered with a dispersion. This exposes the covered and uncovered portions of the surface of the alloy to x-rays by way of an x-ray diffractometry apparatus, making x-ray diffraction determinations of the exposed surface, and measuring the residual stress in the alloy based on these determinations. The dispersion is opaque to x-rays and serves a dual purpose, since it masks off unsatisfactory signals such that only a small portion of the surface is measured, and it supplies an internal standard by providing diffractogram peaks comparable to the peaks of the nickel alloy so that the alloy peaks can be very accurately located regardless of any sources of error external to the sample. 2 figs.

  3. Effects of oxygen partial pressure and annealing temperature on the residual stress of hafnium oxide thin-films on silicon using synchrotron-based grazing incidence X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Biswas, Debaleen; Sinha, Anil Kumar; Chakraborty, Supratic

    2016-10-01

    Synchrotron radiation-based grazing incidence X-ray diffraction (GI-XRD) technique is employed here to estimate the residual stress of < 10 nm thin hafnium oxide film deposited on Si (100) substrate at different argon/oxygen ratios using reactive rf sputtering. A decrease in residual stress, tensile in nature, is observed at higher annealing temperature for the samples deposited with increasing argon ratio in the Ar/O2 plasma. The residual stress of the films deposited at higher pAr (Ar:O2 = 4:1) is also found to be decreased with increasing annealing temperature. But the stress is more or less constant with annealing temperature for the films deposited at lower Ar/O2 (1:4) ratio. All the above phenomena can be explained on the basis of swelling of the interfacial layer and enhanced structural relaxation in the presence of excess Hf in hafnium oxide film during deposition.

  4. Neutron Diffraction Characterization of Residual Strain in Welded Inconel 718 for NASA Space Shuttle Flow Liners

    SciTech Connect

    Rathod, C.R.; Vaidyanathan, R.; Livescu, V.; Clausen, B.; Bourke, M. A. M.; Notardonato, W.U.; Femminineo, M.

    2004-06-28

    This work quantitatively assesses residual strains and stresses associated with the weld repair process used to repair cracks on NASA's space shuttle flow liners. The coupons used in this investigation were made of the same INCONEL 718 alloy used for the flow liners. They were subjected to identical welding and certification procedures that were carried out on the space shuttle. Neutron diffraction measurements at Los Alamos National Laboratory determined residual strains at selected locations in a welded coupon at 293 K and 135 K. The weld repair process introduced Mises effective residual stresses of up to 555 MPa. On comparing the measurements at 293 K and 135 K, no significant change to the residual strain profile was noted at the low temperature. This indicated minimal mismatch in the coefficients of thermal expansion between the base metal and the weld.

  5. Neutron Diffraction Characterization of Residual Strain in Welded Inconel 718 for NASA Space Shuttle Flow Liners

    NASA Astrophysics Data System (ADS)

    Rathod, C. R.; Livescu, V.; Clausen, B.; Bourke, M. A. M.; Notardonato, W. U.; Femminineo, M.; Vaidyanathan, R.

    2004-06-01

    This work quantitatively assesses residual strains and stresses associated with the weld repair process used to repair cracks on NASA's space shuttle flow liners. The coupons used in this investigation were made of the same INCONEL 718 alloy used for the flow liners. They were subjected to identical welding and certification procedures that were carried out on the space shuttle. Neutron diffraction measurements at Los Alamos National Laboratory determined residual strains at selected locations in a welded coupon at 293 K and 135 K. The weld repair process introduced Mises effective residual stresses of up to 555 MPa. On comparing the measurements at 293 K and 135 K, no significant change to the residual strain profile was noted at the low temperature. This indicated minimal mismatch in the coefficients of thermal expansion between the base metal and the weld.

  6. X-ray diffraction analysis of residual stress in zirconia dental composites

    NASA Astrophysics Data System (ADS)

    Allahkarami, Masoud

    Dental restoration ceramic is a complex system to be characterized. Beside its essential biocompatibility, and pleasant appearance, it requires being mechanically strong in a catastrophic loading environment. Any design is restricted with geometry boundary and material property limits. Inspired by natural teeth, a multilayer ceramic is a smart way of achieving an enhanced restoration. Bi-layers of zirconia core covered by porcelain are known as one of the best multilayer restorations. Residual stresses may be introduced into a bi-layer dental ceramic restoration during its entire manufacturing process due to thermal expansion and elastic property mismatch. It is impossible to achieve a free of residual stresses bi-layer zirconia-porcelain restoration. The idea is to take the advantage of residual stress in design in such a way to prevent the crack initiation and progression. The hypothesis is a compressive residual stress at external contact surface would be enabling the restoration to endure a greater tensile stress. Optimizing the layers thickness, manufacturing process, and validating 3D simulations require development of new techniques of thickness, residual stresses and phase transformation measurement. In the present work, a combined mirco-tomography and finite element based method were adapted for thickness measurement. Two new 2D X-ray diffraction based techniques were adapted for phase transformation area mapping and combined phase transformation and residual stress measurement. Concerning the complex geometry of crown, an efficient method for X-ray diffraction data collection mapping on a given curved surface was developed. Finally a novel method for 3D dimensional x-ray diffraction data collection and visualization were introduced.

  7. Characterization of welding residual stresses with neutron diffraction

    SciTech Connect

    Wang, X.L.; Spooner, S.; Hubbard, C.R.; Taljat, B.; Feng, Z.

    1998-03-01

    Welding residual stresses are a key concern in the fabrication and use of structural components containing welds. Residual stresses in welds are caused by non-uniform expansion and shrinkage of differently heated zones during the thermal transient of a weld pass. In some alloys, solid state phase transformations occurring during the welding transient contribute additional residual stresses. Manufacturing problems arising from welding residual stresses include cracking and dimensional distortion. During use, tensile stresses in the welded zone limit the fatigue resistance of the component under cyclic loading. In an aggressive environment, tensile welding residual stresses also create a necessary condition for stress-corrosion cracking to take place.

  8. High energy white beam x-ray diffraction studies of residual strains in engineering components

    NASA Astrophysics Data System (ADS)

    Zhang, S. Y.; Vorster, W.; Jun, T. S.; Song, X.; Golshan, M.; Laundy, D.; Walsh, M. J.; Korsunsky, A. M.

    2008-09-01

    In order to predict the durability of engineering components and improve performance, it is mandatory to understand residual stresses. The last decade has witnessed a significant increase of residual stress evaluation using diffraction of penetrating radiation, such as neutrons or high energy X-rays. They provide a powerful non-destructive method for determining the level of residual stresses in engineering components through precise characterisation of interplanar crystal lattice spacing. The unique non-destructive nature of these measurement techniques is particularly beneficial in the context of engineering design, since it allows the evaluation of a variety of structural and deformational parameters inside real components without material removal, or at worst with minimal interference. However, while most real engineering components have complex shape and are often large in size, leading to measurement and interpretation difficulties, since experimental facilities usually have limited space for mounting the sample, limited sample travel range, limited loading capacity of the sample positioning system, etc. Consequently, samples often have to be sectioned, requiring appropriate corrections on measured data; or facilities must be improved. Our research group has contributed to the development of engineering applications of high-energy X-ray diffraction methods for residual stress evaluation, both at synchrotron sources and in the lab setting, including multiple detector setup, large engineering component manipulation and measurement at the UK Synchrotron Radiation Source (SRS Daresbury), and in our lab at Oxford. A nickel base superalloy combustion casing and a large MIG welded Al alloy plate were successfully studied.

  9. Residual stress determination in an overlay dissimilar welded pipe by neutron diffraction

    SciTech Connect

    Woo, Wan Chuck; Em, Vyacheslav; Hubbard, Camden R; Lee, Ho-Jin; Park, Kwang Soo

    2011-01-01

    Residual stresses were determined through the thickness of a dissimilar weld overlay pipe using neutron diffraction. The specimen has a complex joining structure consisting of a ferritic steel (SA508), austenitic steel (F316L), Ni-based consumable (Alloy 182), and overlay of Ni-base superalloy (Alloy 52M). It simulates pressurized nozzle components, which have been a critical issue under the severe crack condition of nuclear power reactors. Two neutron diffractometers with different spatial resolutions have been utilized on the identical specimen for comparison. The macroscopic 'stress-free' lattice spacing (d{sub o}) was also obtained from both using a 2-mm width comb-like coupon. The results show significant changes in residual stresses from tension (300-400 MPa) to compression (-600 MPa) through the thickness of the dissimilar weld overlay pipe specimen.

  10. Neutron diffraction measurements of time-dependent residual stresses generated by severe thermomechanical deformation

    SciTech Connect

    Woo, Wan Chuck; Feng, Zhili; Wang, Xun-Li; Hubbard, Camden R

    2009-01-01

    Residual stresses were generated by severe thermomechanical deformation in an aluminum alloy plate. The evolution of the residual stresses during natural aging was investigated by neutron diffraction up to 10,000h. A data reduction method was developed to eliminate microstructure influences (solute variations) on the lattice spacing changes, thereby allowing the determination of the long-range macroscopic residual stresses. The residual stress decreased ({approx}25MPa) with time due to the microstructural modification within the deformed region during natural aging.

  11. Residual stress measurements in forced convective quenched steel bars by means of neutron diffraction

    SciTech Connect

    Hernandez-Morales, B.; Hawbolt, B.E.; Brimacombe, J.K.

    1996-12-31

    The residual stress distributions in 38.1 mm-dia., forced convective quenched bars of interstitial-free (IF), 1045 carbon, and alloyed steels were determined by neutron diffraction. The IF and 1045 carbon steel quenched bars exhibited compressive axial and circumferential (hoop) residual stresses near the surface and tensile values at the center. The radial residual stresses were tensile at all radial positions, decreasing towards zero near the surface. In contrast, the measured axial and circumferential components of the residual stress tensor in the alloyed eutectoid steel quenched bar were tensile near the surface and decreased to compressive values at the center. The radial component showed a maximum compressive value at the center and approached zero close to the surface. Metallographic analysis and hardness testing of the three steel specimens, revealed that the IF steel had transformed completely to ferrite, while the 1045 carbon steel bar transformed to martensite near the surface and a mixture of pearlite, ferrite and martensite at the center. On the other hand, the alloyed eutectoid steel specimen transformed entirely to martensite with small amounts of bainite near the center of the rod. The observed differences in the residual stress distributions in the three steels were explained based on the sequence of phase transformations that took place during quenching.

  12. Weighted mechanical models for residual stress determination using x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Murray, Conal E.; Bedell, Stephen W.; Ryan, E. Todd

    2013-07-01

    Determining the mechanical response of thin films by diffraction-based methods requires appropriate elastic models. Weighting factors associated with the linear combination of Reuss and Voigt x-ray elastic constants are compared to the experimental values determined through linear, least-squares regression of diffraction data collected from multiple reflections of several materials. It is found that the optimal weighting factors, x*, determined by the experimental data of Cu, Ni, and Ti thin films vary significantly from those calculated under the Kröner and Neerfeld limits. The discrepancies may be due to plastic effects on the mechanical models that assume linear elastic behavior. The corresponding residual stress values under these limits exhibit a closer correspondence, where the relative variation among the mechanical models scales with the elastic anisotropy of the material.

  13. Neutron diffraction measurements of residual stresses in friction stir welding: a review

    SciTech Connect

    Woo, Wan Chuck; Feng, Zhili; Wang, Xun-Li; David, Stan A

    2011-01-01

    Significant amounts of residual stresses are often generated during welding and result in critical degradation of the structural integrity and performance of components. Neutron diffraction has become a well established technique for the determination of residual stresses in welds because of the unique deep penetration, three-dimensional mapping capability, and volume averaged bulk measurements characteristic of the scattering neutron beam. Friction stir welding has gained prominence in recent years. The authors reviewed a number of neutron diffraction measurements of residual stresses in friction stir welds and highlighted examples addressing how the microstructures and residual stresses are correlated with each other. An example of in situ neutron diffraction measurement result shows the evolution of the residual stresses during welding.

  14. Residual Stress Analysis in Deep Drawn Twinning Induced Plasticity (TWIP) Steels Using Neutron Diffraction Method

    NASA Astrophysics Data System (ADS)

    Hong, Seokmin; Lee, Junghoon; Lee, Sunghak; Woo, Wanchuck; Kim, Sung-Kyu; Kim, Hyoung Seop

    2014-04-01

    In Twinning Induced Plasticity (TWIP) steels, delayed fracture occurs due to residual stresses induced during deep drawing. In order to investigate the relation between residual stresses and delayed fracture, in the present study, residual stresses of deep drawn TWIP steels (22Mn-0.6C and 18Mn-2Al-0.6C steels) were investigated using the finite element method (FEM) and neutron diffraction measurements. In addition, the delayed fracture properties were examined by dipping tests of cup specimens in the boiled water. In the FEM analysis, the hoop direction residual stress was highly tensile at cup edge, and the delayed fracture was initiated by the separation of hoop direction and propagated in an axial direction. According to the neutron diffraction analysis, residual stresses in 18Mn-2Al-0.6C steel were about half the residual stresses in 22Mn-0.6C steel. From the residual strain measurement using electron back-scatter diffraction, formation of deformation twins caused a lot of grain rotation and local strain at the grain boundaries and twin boundaries. These local residual strains induce residual stress at boundaries. Al addition in TWIP steels restrained the formation of deformation twins and dynamic strain aging, resulting in more homogeneous stress and strain distributions in cup specimens. Thus, in Al-added TWIP steels, residual stress of cup specimen considerably decreased, and delayed fracture resistance was remarkably improved by the addition of Al in TWIP steels.

  15. Neutron diffraction residual stress studies for aero-engine component applications

    NASA Astrophysics Data System (ADS)

    Clay, K.; Small, C.

    1991-12-01

    Computer graphics for a presentation describing how Rolls-Royce is refining the method of residual stress measurement by neutron diffraction to suit the characteristic stress fields of components are presented. Results to date are given. An outline of how this residual stress data is to be used in developing stress models for critical rotating components is given.

  16. Neutron diffraction analysis of residual stresses near unannealed welds in anhydrous ammonia nurse tanks.

    PubMed

    Becker, A T; Chumbley, L S; Goettee, D; Russell, A M

    2014-01-01

    Neutron diffraction analysis was employed to measure residual stresses near welds in used anhydrous ammonia nurse tanks. Tensile residual stresses contribute to stress corrosion cracking of nurse tanks, which can cause tanks to release toxic ammonia vapor. The analysis showed that tensile residual stresses were present in the tanks measured, and the magnitudes of these stresses approached the yield strength of the steel. Implications for agricultural safety and health are discussed.

  17. Volumetric measurement of residual stress using high energy x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Whitesell, R.; McKenna, A.; Wendt, S.; Gray, J.

    2016-02-01

    We present results and recent developments from our laboratory, bench-top high energy x-ray diffraction system (HEXRD), between diffraction energies 50 and 150 KeV, to measure internal strain of moderately sized objects. Traditional x-ray strain measurements are limited to a few microns depth due to the use of Cu Kα1 Mo Kα1 radiation. The use of high energy x-rays for volumetric measurements of strain is typically the domain of synchrotron sources. We discuss the use of industrial 320kVp tube sources to generate a brighter x-ray beam along with a method using the intrinsic 43 eV width of the Kα1 characteristic peak of tungsten to measure volumetric strains in a number of industrially relevant materials. We will present volumetric strain measurements from two examples, first, additive manufacturing (AM) parts with various build configurations and, secondly, residual strain depth profiles from shot peened surface treatments. The spatial resolution of these depth profiles is ˜75 microns. The development of a faster method as compared to energy dispersive or θ-2θ scans is based on the intensity variation measurement of the strain using the aforementioned 43 eV characteristic tungsten kα line. We will present recent results on the development of this new tool and on x-ray diffraction measurements at high energy.

  18. On the reliability of neutron diffraction for residual stress measurement in cold-drawn steels

    NASA Astrophysics Data System (ADS)

    Ruiz-Hervias, J.; Mompean, F.; Hofmann, M.; Atienza, J. M.

    2011-10-01

    Residual strains were measured in the ferrite phase of pearlitic steel rods along the radial, axial and hoop directions. Two samples with different initial diameters were subjected to one drawing pass (using same drawing parameters) with 20% section reduction and measured in two different neutron diffraction instruments. The results show that the residual strain state is very similar in both cases, regardless of the diameter of the initial rod. This means that the final residual strain-stress state is unique and it is related to the cold-drawing process parameters. In addition, the results show the reliability of strain scanning with different neutron instruments and experimental conditions.

  19. Determination of the residual stress tensor in textured zirconium alloy by neutron diffraction

    NASA Astrophysics Data System (ADS)

    Sumin, V. V.; Papushkin, I. V.; Vasin, R. N.; Venter, А. M.; Balagurov, А. М.

    2012-02-01

    Results of neutron diffraction studies of crystallographic texture and residual stress tensor components in cold-worked and annealed cylindrical components made from E-110 zirconium alloy are presented. Those components are used as plugs in the fuel elements of the VVER-type reactors; the resident residual stresses influence the durability and safety of the fuel elements. The experiments were carried out on the neutron diffractometers at Dubna (the IBR-2 pulsed reactor) and Berlin Helmholtz-Zentrum (the BER II research reactor). It is shown that the samples have fiber texture that is changed considerably with annealing. The type I residual stress tensors for both samples were calculated by the BulkPathGEO model. The cold worked component has 136-166 MPa tensile residual stress in the radial direction and zero stress along the axial direction. Residual stress values in the annealed component are close to zero.

  20. In Situ Tensile Deformation and Residual Stress Measurement by Neutron Diffraction in Modified 9Cr-1Mo Steel

    NASA Astrophysics Data System (ADS)

    Shrestha, Triratna; Charit, Indrajit; Potirniche, Gabriel

    2015-12-01

    The deformation behavior of monolithic modified 9Cr-1Mo (Grade 91) steel during uniaxial tensile loading was studied using the in situ neutron diffraction technique. The residual stress distribution across gas tungsten arc welds in the Grade 91 steel was measured by the time-of-flight neutron diffraction method using the SMARTS diffractometer at Lujan Neutron Scattering Center, Los Alamos National Laboratory. Grade 91 plates were welded using the gas tungsten arc welding (GTAW) technique. The load sharing by different grain orientations was observed during the tensile loading. The residual stresses along three orthogonal directions were determined at the mid-thickness, 4.35 and 2.35 mm below the surface of both the as-welded and post-weld heat-treated plates. The residual stresses of the as-welded plates were compared with those of the post-weld heat-treated plates. The post-weld heat treatment significantly reduced the residual stress level in the base metal, the heat-affected zone, and the weld zone. Vickers microhardness across the weld zone of the as-welded and post-weld heat-treated specimens was evaluated and correlated with the observed residual stress profile and microstructure.

  1. X-ray and neutron diffraction determination of residual stresses in a pressed and welded component

    NASA Astrophysics Data System (ADS)

    Albertini, G.; Bruno, G.; Fiori, F.; Girardin, E.; Giuliani, A.; Quadrini, E.

    2000-03-01

    X-ray and neutron diffraction experiments have been carried out, in order to determine the residual stress (RS) field in a pressed and welded mock-up of an engine support for motor-bike technology. Such investigation is suggested by the need to know the stress state of the component after forming and welding. This allows to assess the quality of the first machining and further to theoretically simulate its performances under operation. Results are presented below, showing a good agreement between X-ray and neutron diffraction experiments.

  2. Neutron diffraction measurements and modeling of residual strains in metal matrix composites

    SciTech Connect

    Saigal, A.; Leisk, G.G.; Hubbard, C.R.; Misture, S.T.; Wang, X.L.

    1996-04-01

    Neutron diffraction measurements at room temperature are used to characterize the residual strains in tungsten fiber-reinforced copper matrix, tungsten fiber-reinforced Kanthal matrix, and diamond particulate-reinforced copper matrix composites. Results of finite element modeling are compared with the neutron diffraction data. In tungsten/Kanthal composites, the fibers are in compression, the matrix is in tension, and the thermal residual strains are a strong function of the volume fraction of fibers. In copper matrix composites, the matrix is in tension and the stresses are independent of the volume fraction of tungsten fibers or diamond particles and the assumed stress free temperature because of the low yield strength of the matrix phase.

  3. Neutron diffraction measurements and modeling of residual strains in metal matrix composites

    NASA Technical Reports Server (NTRS)

    Saigal, A.; Leisk, G. G.; Hubbard, C. R.; Misture, S. T.; Wang, X. L.

    1996-01-01

    Neutron diffraction measurements at room temperature are used to characterize the residual strains in tungsten fiber-reinforced copper matrix, tungsten fiber-reinforced Kanthal matrix, and diamond particulate-reinforced copper matrix composites. Results of finite element modeling are compared with the neutron diffraction data. In tungsten/Kanthal composites, the fibers are in compression, the matrix is in tension, and the thermal residual strains are a strong function of the volume fraction of fibers. In copper matrix composites, the matrix is in tension and the stresses are independent of the volume fraction of tungsten fibers or diamond particles and the assumed stress free temperature because of the low yield strength of the matrix phase.

  4. INTERFACE RESIDUAL STRESSES IN DENTAL ZIRCONIA USING LAUE MICRO-DIFFRACTION

    SciTech Connect

    Bale, H. A.; Tamura, N.; Coelho, P.G.; Hanan, J. C.

    2009-01-01

    Due to their aesthetic value and high compressive strength, dentists have recently employed ceramics for restoration materials. Among the ceramic materials, zirconia provides high toughness and crack resistant characteristics. Residual stresses develop in processing due to factors including grain anisotropy and thermal coefficient mismatch. In the present study, polychromatic X-ray (Laue) micro-diffraction provided grain orientation and residual stresses on a clinically relevant zirconia model ceramic disk. A 0.5 mm x 0.024 mm region on zirconia was examined on a 500 nm scale for residual stresses using a focused poly-chromatic synchrotron X-ray beam. Large stresses ranging from - to + 1GPa were observed at some grains. On average, the method suggests a relatively small compressive stress at the surface between 47 and 75 MPa depending on direction.

  5. Neutron diffraction determination of the residual stress redistribution in cracked autofrettaged tubing

    SciTech Connect

    Bourke, M.A. ); McGillivray, H.J.; Webster, G.A. . Dept. of Mechanical Engineering); Webster, P.J. . Dept. of Civil Engineering)

    1991-01-01

    Neutron diffraction has been used to measure the residual stress distributions in uncracked and fatigue cracked rings taken from a high strength, low alloy steel autofrettage tube with a bore diameter of 60mm and a wall thickness of 32mm. Stresses were determined to a precision of {plus minus} 10MPa. Three crack sixes were examines. No appreciable stress redistribution was observed until the crack was grown into a region which originally contained tensile residual hoop stress. When this occurred an increase in residual hoop tension was observed ahead of the crick tip. Qualitative agreement was achieved between the measured hoop stress distribution and values predicted using a boundary element method. 9 refs., 12 figs.

  6. Verification of residual stresses in flash-butt-weld rails using neutron diffraction

    NASA Astrophysics Data System (ADS)

    Tawfik, David; Kirstein, Oliver; Mutton, Peter John; Chiu, Wing Kong

    2006-11-01

    Residual stresses developed during flash-butt welding may play a crucial role in prolonging the fatigue life of the welded tracks under service loading conditions. The finished welds typically exhibit high levels of tensile residual stresses in the web region of the weld. Moreover, the surface condition of the web may contain shear drag or other defects resulting from the shearing process which may lead to the initiation and propagation of fatigue cracks in a horizontal split web failure mode under high axle loads. However, a comprehensive understanding into the residual stress behaviour throughout the complex weld geometry remains unclear and is considered necessary to establish the correct localised post-weld heat treatment modifications intended to lower tensile residual stresses. This investigation used the neutron diffraction technique to analyse residual stresses in an AS60 flash-butt-welded rail cooled under normal operating conditions. The findings will ultimately contribute to developing modifications to the flash-butt-welding procedure to lower tensile residual stresses which may then improve rail performance under high axle load.

  7. Migration velocity analysis using residual diffraction moveout: a real-data example

    NASA Astrophysics Data System (ADS)

    Gonzalez, Jaime A. C.; de Figueiredo, José J. S.; Coimbra, Tiago A.; Schleicher, Jörg; Novais, Amélia

    2016-08-01

    Unfocused seismic diffraction events carry direct information about errors in the migration-velocity model. The residual-diffraction-moveout (RDM) migration-velocity-analysis (MVA) method is a recent technique that extracts this information by means of adjusting ellipses or hyperbolas to uncollapsed migrated diffractions. In this paper, we apply this method, which has been tested so far only on synthetic data, to a real data set from the Viking Graben. After application of a plane-wave-destruction (PWD) filter to attenuate the reflected energy, the diffractions in the real data become interpretable and can be used for the RDM method. Our analysis demonstrates that the reflections need not be completely removed for this purpose. Beyond the need to identify and select diffraction events in post-stack migrated sections in the depth domain, the method has a very low computational cost and processing time. To reach an acceptable velocity model of comparable quality as one obtained with common-midpoint (CMP) processing, only two iterations were necessary.

  8. Calculation of the diffraction efficiency on concave gratings based on Fresnel-Kirchhoff's diffraction formula.

    PubMed

    Huang, Yuanshen; Li, Ting; Xu, Banglian; Hong, Ruijin; Tao, Chunxian; Ling, Jinzhong; Li, Baicheng; Zhang, Dawei; Ni, Zhengji; Zhuang, Songlin

    2013-02-10

    Fraunhofer diffraction formula cannot be applied to calculate the diffraction wave energy distribution of concave gratings like plane gratings because their grooves are distributed on a concave spherical surface. In this paper, a method based on the Kirchhoff diffraction theory is proposed to calculate the diffraction efficiency on concave gratings by considering the curvature of the whole concave spherical surface. According to this approach, each groove surface is divided into several limited small planes, on which the Kirchhoff diffraction field distribution is calculated, and then the diffraction field of whole concave grating can be obtained by superimposition. Formulas to calculate the diffraction efficiency of Rowland-type and flat-field concave gratings are deduced from practical applications. Experimental results showed strong agreement with theoretical computations. With the proposed method, light energy can be optimized to the expected diffraction wave range while implementing aberration-corrected design of concave gratings, particularly for the concave blazed gratings.

  9. Optical image encryption based on diffractive imaging.

    PubMed

    Chen, Wen; Chen, Xudong; Sheppard, Colin J R

    2010-11-15

    In this Letter, we propose a method for optical image encryption based on diffractive imaging. An optical multiple random phase mask encoding system is applied, and one of the phase-only masks is selected and laterally translated along a preset direction during the encryption process. For image decryption, a phase retrieval algorithm is proposed to extract a high-quality plaintext. The feasibility and effectiveness of the proposed method are demonstrated by numerical results. The proposed method can provide a new strategy instead of conventional interference methods, and it may open up a new research perspective for optical image encryption.

  10. Nondestructive evaluation of residual stress in short-fiber reinforced plastics by x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Tanaka, Keisuke; Tokoro, Syouhei; Akiniwa, Yoshiaki; Egami, Noboru

    2014-06-01

    The X-ray diffraction method is used to measure the residual stress in injection-molded plates of short-fiber reinforced plastics (SFRP) made of crystalline thermoplastics, polyphenylene sulphide (PPS), reinforced by carbon fibers with 30 mass%. Based on the orientation of carbon fibers, injection molded plates can be modeled as three-layered lamella where the core layer is sandwiched by skin layers. The stress in the matrix in the skin layer was measured using Cr-Kα radiation with the sin2Ψ method. Since the X-ray penetration depth is shallow, the state of stresses measured by X-rays in FRP can be assumed to be plane stress. The X-ray measurement of stress in carbon fibers was not possible because of high texture. A new method was proposed to evaluate the macrostress in SFRP from the measurement of the matrix stress. According to micromechanics analysis of SFRP, the matrix stresses in the fiber direction, σ1m, and perpendicular to the fiber direction, σ2m, and shear stress τ12m can be expressed as the functions of the applied (macro-) stresses, σ1A, σ2A , τ12A as follows: σ1m = α11σ1A +α12σ2A, σ2m = α21σ1A + α22σ2A, τ12m = α66τ12A, where α11 ,α12, α21, α22, α66 are stress-partitioning coefficients. Using skin-layer strips cut parallel, perpendicular and 45° to the molding direction, the stress in the matrix was measured under the uniaxial applied stress and the stress-partitioning coefficients of the above equations were determined. Once these relations are established, the macrostress in SFRP can be determined from the measurements of the matrix stresses by X-rays.

  11. Residual Stresses in DC cast Aluminum Billet: Neutron Diffraction Measurements and Thermomechanical Modeling

    SciTech Connect

    Drezet, J.-M.; Evans, A.; Pirling, T.

    2011-05-04

    Thermally-induced residual stresses, generated during the industrial Direct Chill casting process of aluminum alloys, can cause both significant safety concerns as well as the formation of defects during down-stream processing. Although these thermally induced strains can be partially relieved by permanent deformation, cracks will be generated either during solidification (hot tears) or post-solidification cooling (cold cracks) when stresses exceed the deformation limit of the alloy. Furthermore, the thermally induced strains result in the presence of large internal stresses within the billet before further processing steps. Although numerical models have been previously developed to compute these residual stresses, most of the computations have been validated only against measured surface distortions. In the present work, the variation in residual elastic strains and stresses in the steady state regime of casting has been measured as a function of radial position using neutron diffraction in an AA6063 grain-refined cylindrical billet. These measurements have been carried out on the same billet section at Poldi at PSI-Villigen and at Salsa at ILL-Grenoble and compare favorably. The results are used to validate a thermo-mechanical finite element casting model and to assess the level of stored elastic energy within the billet.

  12. Residual Stresses in DC cast Aluminum Billet: Neutron Diffraction Measurements and Thermomechanical Modeling

    NASA Astrophysics Data System (ADS)

    Drezet, J.-M.; Evans, A.; Pirling, T.

    2011-05-01

    Thermally-induced residual stresses, generated during the industrial Direct Chill casting process of aluminum alloys, can cause both significant safety concerns as well as the formation of defects during down-stream processing. Although these thermally induced strains can be partially relieved by permanent deformation, cracks will be generated either during solidification (hot tears) or post-solidification cooling (cold cracks) when stresses exceed the deformation limit of the alloy. Furthermore, the thermally induced strains result in the presence of large internal stresses within the billet before further processing steps. Although numerical models have been previously developed to compute these residual stresses, most of the computations have been validated only against measured surface distortions. In the present work, the variation in residual elastic strains and stresses in the steady state regime of casting has been measured as a function of radial position using neutron diffraction in an AA6063 grain-refined cylindrical billet. These measurements have been carried out on the same billet section at Poldi at PSI-Villigen and at Salsa at ILL-Grenoble and compare favorably. The results are used to validate a thermo-mechanical finite element casting model and to assess the level of stored elastic energy within the billet.

  13. Neutron diffraction measurements of residual strains in tungsten fiber-reinforced Kanthal composites

    SciTech Connect

    Saigal, A.; Leisk, G.G.; Misture, S.T.; Hubbard, C.R.

    1996-04-15

    FeAl and FeCrAl alloys containing small quantities of Y, such as Kanthal, have been shown to exhibit outstanding high-temperature oxidation/corrosion resistance and therefore have great potential for use as corrosion-resistant cladding in a variety of high-temperature structural applications. Recently, several such FeAl alloys have been developed with improved mechanical behavior and weldability. In order to further enhance strength, tungsten fiber-reinforced Kanthal metal matrix composites have been developed for possible applications in space structures. However, thermal residual stresses are developed as a result of the mismatch of the coefficients of thermal expansion between those of the tungsten fibers and the Kanthal matrix during post-fabrication cooldown. These stresses can lead to matrix cracking, thereby deteriorating the aggregate mechanical properties of the composites. To develop composites with reliable and enhanced properties, it is necessary to understand the nature and the magnitude of these residual stresses. High-resolution neutron powder diffraction was used in this study to investigate the residual strains and stresses at room temperature in W/Kanthal composites containing different volume fractions of tungsten fibers.

  14. X-ray Laue micro diffraction and neutron diffraction analysis of residual elastic strains and plastic deformation in a 1% uniaxial tensile tested nickel alloy 600 sample

    SciTech Connect

    Chao, Jing; Mark, Alison; Fuller, Marina; Barabash, Rozaliya; McIntyre, Stewart; Holt, Richard A.; Klassen, Robert; Liu, W.

    2009-01-01

    The magnitude and distribution of elastic strain for a nickel alloy 600 (A600) sample that had been subjected to uniaxial tensile stress were measured by micro Laue diffraction (MLD) and neutron diffraction techniques. For a sample that had been dimensionally strained by 1%, both MLD and neutron diffraction data indicated that the global residual elastic strain was on the order of 10{sup -4}, however the micro-diffraction data indicated considerable grain-to-grain variability amongst individual components of the residual strain tensor. A more precise comparison was done by finding those grains in the MLD map that had appropriate oriented in the specific directions matching those used in the neutron measurements and the strains were found to agree within the uncertainty. Large variations in strain values across the grains were noted during the MLD measurements which are reflected in the uncertainties. This is a possible explanation for the large uncertainty in the average strains measured from multiple grains during neutron diffraction.

  15. Fast diffraction computation algorithms based on FFT

    NASA Astrophysics Data System (ADS)

    Logofatu, Petre Catalin; Nascov, Victor; Apostol, Dan

    2010-11-01

    The discovery of the Fast Fourier transform (FFT) algorithm by Cooley and Tukey meant for diffraction computation what the invention of computers meant for computation in general. The computation time reduction is more significant for large input data, but generally FFT reduces the computation time with several orders of magnitude. This was the beginning of an entire revolution in optical signal processing and resulted in an abundance of fast algorithms for diffraction computation in a variety of situations. The property that allowed the creation of these fast algorithms is that, as it turns out, most diffraction formulae contain at their core one or more Fourier transforms which may be rapidly calculated using the FFT. The key in discovering a new fast algorithm is to reformulate the diffraction formulae so that to identify and isolate the Fourier transforms it contains. In this way, the fast scaled transformation, the fast Fresnel transformation and the fast Rayleigh-Sommerfeld transform were designed. Remarkable improvements were the generalization of the DFT to scaled DFT which allowed freedom to choose the dimensions of the output window for the Fraunhofer-Fourier and Fresnel diffraction, the mathematical concept of linearized convolution which thwarts the circular character of the discrete Fourier transform and allows the use of the FFT, and last but not least the linearized discrete scaled convolution, a new concept of which we claim priority.

  16. Quantitative measurement of phase variation amplitude of ultrasonic diffraction grating based on diffraction spectral analysis

    SciTech Connect

    Pan, Meiyan Zeng, Yingzhi; Huang, Zuohua

    2014-09-15

    A new method based on diffraction spectral analysis is proposed for the quantitative measurement of the phase variation amplitude of an ultrasonic diffraction grating. For a traveling wave, the phase variation amplitude of the grating depends on the intensity of the zeroth- and first-order diffraction waves. By contrast, for a standing wave, this amplitude depends on the intensity of the zeroth-, first-, and second-order diffraction waves. The proposed method is verified experimentally. The measured phase variation amplitude ranges from 0 to 2π, with a relative error of approximately 5%. A nearly linear relation exists between the phase variation amplitude and driving voltage. Our proposed method can also be applied to ordinary sinusoidal phase grating.

  17. Structure-based identification of catalytic residues.

    PubMed

    Yahalom, Ran; Reshef, Dan; Wiener, Ayana; Frankel, Sagiv; Kalisman, Nir; Lerner, Boaz; Keasar, Chen

    2011-06-01

    The identification of catalytic residues is an essential step in functional characterization of enzymes. We present a purely structural approach to this problem, which is motivated by the difficulty of evolution-based methods to annotate structural genomics targets that have few or no homologs in the databases. Our approach combines a state-of-the-art support vector machine (SVM) classifier with novel structural features that augment structural clues by spatial averaging and Z scoring. Special attention is paid to the class imbalance problem that stems from the overwhelming number of non-catalytic residues in enzymes compared to catalytic residues. This problem is tackled by: (1) optimizing the classifier to maximize a performance criterion that considers both Type I and Type II errors in the classification of catalytic and non-catalytic residues; (2) under-sampling non-catalytic residues before SVM training; and (3) during SVM training, penalizing errors in learning catalytic residues more than errors in learning non-catalytic residues. Tested on four enzyme datasets, one specifically designed by us to mimic the structural genomics scenario and three previously evaluated datasets, our structure-based classifier is never inferior to similar structure-based classifiers and comparable to classifiers that use both structural and evolutionary features. In addition to the evaluation of the performance of catalytic residue identification, we also present detailed case studies on three proteins. This analysis suggests that many false positive predictions may correspond to binding sites and other functional residues. A web server that implements the method, our own-designed database, and the source code of the programs are publicly available at http://www.cs.bgu.ac.il/∼meshi/functionPrediction.

  18. Magnetic Barkhausen Noise and Neutron Diffraction Techniques for the Study of Intergranular Residual Strains in Mild Steel

    SciTech Connect

    Hutanu, Roxana; Clapham, Lynann; Rogge, Ronald

    2004-02-26

    Intergranular residual stresses (IS) are microscopic residual stresses which have been found to accumulate along the <100> direction in steels. The <100> direction is also the magnetic easy axis direction in steel. This work involved Magnetic Barkhausen Noise (MBN) studies on steel samples, deformed uniaxially to increasing levels of strain. The MBN results indicated that a bulk magnetic easy axis was produced by the deformation process, and neutron diffraction experiments showed that this easy axis was correlated with the tensile strain in grains oriented in the <100> direction.

  19. The application of neutron diffraction to stress mapping in pipeline steels: Measurement of residual, applied, and defect-induced stresses

    SciTech Connect

    Clapham, L.; Krause, T.W.; Olsen, H.; Atherton, D.L.; Holden, T.M.

    1996-12-31

    Gas pipelines are inspected for defects including generalized corrosion, localized corrosion and environmentally-induced cracking. The most common in-line corrosion inspection tools utilize the magnetic flux leakage (MFL) technique, which is also sensitive to the pipeline stress state. Accurate determination of the residual, applied (bulk) and local defect-induced stresses is therefore essential to understand how stress affects MFL signals. This paper summarizes the results of the following work: (1) Measurement of residual stresses in a section of X70 pipe, using neutron diffraction. (2) Examination with neutron diffraction of the local stresses surrounding a blind (i.e., 50% through-wall) hole defect in the X70 pipe wall section, when the section is subjected to a bending stress in the hoop direction.

  20. Angle-resolved diffraction grating biosensor based on porous silicon

    NASA Astrophysics Data System (ADS)

    Lv, Changwu; Jia, Zhenhong; Liu, Yajun; Mo, Jiaqing; Li, Peng; Lv, Xiaoyi

    2016-03-01

    In this study, an optical biosensor based on a porous silicon composite structure was fabricated using a simple method. This structure consists of a thin, porous silicon surface diffraction grating and a one-dimensional porous silicon photonic crystal. An angle-resolved diffraction efficiency spectrum was obtained by measuring the diffraction efficiency at a range of incident angles. The angle-resolved diffraction efficiency of the 2nd and 3rd orders was studied experimentally and theoretically. The device was sensitive to the change of refractive index in the presence of a biomolecule indicated by the shift of the diffraction efficiency spectrum. The sensitivity of this sensor was investigated through use of an 8 base pair antifreeze protein DNA hybridization. The shifts of the angle-resolved diffraction efficiency spectrum showed a relationship with the change of the refractive index, and the detection limit of the biosensor reached 41.7 nM. This optical device is highly sensitive, inexpensive, and simple to fabricate. Using shifts in diffraction efficiency spectrum to detect biological molecules has not yet been explored, so this study establishes a foundation for future work.

  1. Six Classes of Diffraction-Based Optoelectronic Instruments

    NASA Technical Reports Server (NTRS)

    Spremo, Stevan; Fuhr, Peter; Schipper, John

    2003-01-01

    Six classes of diffraction-based optoelectronic instruments have been invented as means for wavelength-based processing of light. One family of anticipated applications lies in scientific instrumentation for studying chemical and physical reactions that affect and/or are affected differently by light of different wavelengths or different combinations of wavelengths. Another family of anticipated applications lies in optoelectronic communication systems.

  2. Neutron Diffraction Residual Strain Tensor Measurements Within The Phase IA Weld Mock-up Plate P-5

    SciTech Connect

    Hubbard, Camden R

    2011-09-01

    Oak Ridge National Laboratory (ORNL) has worked with NRC and EPRI to apply neutron and X-ray diffraction methods to characterize the residual stresses in a number of dissimilar metal weld mockups and samples. The design of the Phase IA specimens aimed to enable stress measurements by several methods and computational modeling of the weld residual stresses. The partial groove in the 304L stainless steel plate was filled with weld beads of Alloy 82. A summary of the weld conditions for each plate is provided in Table 1. The plates were constrained along the long edges during and after welding by bolts with spring-loaded washers attached to the 1-inch thick Al backing plate. The purpose was to avoid stress relief due to bending of the welded stainless steel plate. The neutron diffraction method was one of the methods selected by EPRI for non-destructive through thickness strain and stress measurement. Four different plates (P-3 to P-6) were studied by neutron diffraction strain mapping, representing four different welding conditions. Through thickness neutron diffraction strain mappings at NRSF2 for the four plates and associated strain-free d-zero specimens involved measurement along seven lines across the weld and at six to seven depths. The mountings of each plate for neutron diffraction measurements were such that the diffraction vector was parallel to each of the three primary orthogonal directions of the plate: two in-plane directions, longitudinal and transverse, and the direction normal to the plate (shown in left figure within Table 1). From the three orthogonal strains for each location, the residual stresses along the three plate directions were calculated. The principal axes of the strain and stress tensors, however, need not necessarily align with the plate coordinate system. To explore this, plate P-5 was selected for examination of the possibility that the principal axes of strain are not along the sample coordinate system axes. If adequate data could

  3. As-Cast Residual Stresses in an Aluminum Alloy AA6063 Billet: Neutron Diffraction Measurements and Finite Element Modeling

    NASA Astrophysics Data System (ADS)

    Drezet, J.-M.; Phillion, A. B.

    2010-12-01

    The presence of thermally induced residual stresses, created during the industrial direct chill (DC) casting process of aluminum alloys, can cause both significant safety concerns and the formation of defects during downstream processing. Although numerical models have been previously developed to compute these residual stresses, most of the computations have been validated only against measured surface distortions. Recently, the variation in residual elastic strains in the steady-state regime of casting has been measured as a function of radial position using neutron diffraction (ND) in an AA6063 grain-refined cylindrical billet. In the present study, these measurements are used to show that a well-designed thermomechanical finite element (FE) process model can reproduce relatively well the experimental results. A sensitivity analysis is then carried out to determine the relative effect of the various mechanical parameters when computing the as-cast residual stresses in a cylindrical billet. Two model parameters have been investigated: the temperature when the alloy starts to thermally contract and the plasticity behavior. It is shown that the mechanical properties at low temperatures have a much larger influence on the residual stresses than those at high temperatures.

  4. Texture, residual strain, and plastic deformation around scratches in alloy 600 using synchrotron x-ray Laue micro-diffraction.

    SciTech Connect

    Suominen Fuller, M. L.; Klassen, R. J.; McIntyre, N. S.; Gerson, A. R.; Ramamurthy, S.; King, P. J.; Liu, W.; Univ. of Western Ontario; Univ. of South Australia; Babcock & Wilcox Canada

    2008-01-01

    Deformation around two scratches in Alloy 600 (A600) was studied nondestructively using synchrotron Laue differential aperture X-ray microscopy. The orientation of grains and elastic strain distribution around the scratches were measured. A complex residual deviatoric elastic strain state was found to exist around the scratches. Heavy plastic deformation was observed up to a distance of 20 {micro}m from the scratches. In the region 20-30 {micro}m from the scratches the diffraction spots were heavily streaked and split indicating misoriented dislocation cell structures.

  5. Nanoscale characterisation by SANS and residual stresses determination by neutron diffraction related to materials and components of technological interest

    NASA Astrophysics Data System (ADS)

    Rogante, Massimo; Rosta, Laszlo

    2005-06-01

    Neutron techniques, among the other non-destructive diagnostics, are becoming more and more relevant in investigating materials and components of industrial interest. In this paper, Small Angle Neutron Scattering (SANS) for microstructural characterisation-especially related to the nanoscale-and Neutron Diffraction for Residual Stresses (RS) measurements are considered. The basic theoretical aspects and some industrial applications of each technique are described. In particular, RS determination in welding, in extruded specimens and in components for energy industry is reported. SANS measurements concerning materials and components for energy and automotive industry are finally presented.

  6. High spatial resolution, high energy synchrotron x-ray diffraction characterization of residual strains and stresses in laser shock peened Inconel 718SPF alloy

    NASA Astrophysics Data System (ADS)

    Gill, Amrinder S.; Zhou, Zhong; Lienert, Ulrich; Almer, Jonathan; Lahrman, David F.; Mannava, S. R.; Qian, Dong; Vasudevan, Vijay K.

    2012-04-01

    Laser shock peening (LSP) is an advanced surface enhancement technique used to enhance the fatigue strength of metal parts by imparting deep compressive residual stresses. In the present study, LSP was performed on IN718 SPF alloy, a fine grained nickel-based superalloy, with three different power densities and depth resolved residual strain and stress characterization was conducted using high energy synchrotron x-ray diffraction in beam line 1-ID-C at the Advanced Photon Source at the Argonne National laboratory. A fine probe size and conical slits were used to non-destructively obtain data from specific gauge volumes in the samples, allowing for high-resolution strain measurements. The results show that LSP introduces deep compressive residual stresses and the magnitude and depth of these stresses depend on the energy density of the laser. The LSP induced residual stresses were also simulated using three-dimensional nonlinear finite element analysis, with employment of the Johnson-Cook model for describing the nonlinear materials constitutive behavior. Good agreement between the experimental and simulated data was obtained. These various results are presented and discussed.

  7. Residual strain gradient determination in metal matrix composites by synchrotron X-ray energy dispersive diffraction

    NASA Technical Reports Server (NTRS)

    Kuntz, Todd A.; Wadley, Haydn N. G.; Black, David R.

    1993-01-01

    An X-ray technique for the measurement of internal residual strain gradients near the continuous reinforcements of metal matrix composites has been investigated. The technique utilizes high intensity white X-ray radiation from a synchrotron radiation source to obtain energy spectra from small (0.001 cu mm) volumes deep within composite samples. The viability of the technique was tested using a model system with 800 micron Al203 fibers and a commercial purity titanium matrix. Good agreement was observed between the measured residual radial and hoop strain gradients and those estimated from a simple elastic concentric cylinders model. The technique was then used to assess the strains near (SCS-6) silicon carbide fibers in a Ti-14Al-21Nb matrix after consolidation processing. Reasonable agreement between measured and calculated strains was seen provided the probe volume was located 50 microns or more from the fiber/matrix interface.

  8. Residual stress measurements in a zircaloy-4 weld by neutron diffraction

    SciTech Connect

    Carr, D.G.; Ripley, M.I.; Holden, T.M.; Brown, D.W.; Vogel, S.C

    2004-08-16

    The macroscopic stress distribution across a Zircaloy-4 gas tungsten arc weld was measured by time-of-flight neutron diffraction at the SMARTS diffractometer at Los Alamos National Laboratory. The method enabled the measurement of strain for all the available reflections permitted by the rolling texture of the plate and the modified texture in the weld-metal and heat affected zone. A maximum longitudinal stress of 220 {+-} 40 MPa was observed in the weld compared with the 0.2% yield stress of 390 MPa of the plate. A maximum transverse stress of 60 {+-} 40 MPa was observed in the weld. Textures were measured at the HIPPO diffractometer.

  9. Goniometer-based femtosecond X-ray diffraction of mutant 30S ribosomal subunit crystals

    SciTech Connect

    Dao, E. Han; Sierra, Raymond G.; Laksmono, Hartawan; Lemke, Henrik T.; Alonso-Mori, Roberto; Coey, Aaron; Larsen, Kevin; Baxter, Elizabeth L.; Cohen, Aina E.; Soltis, S. Michael; DeMirci, Hasan

    2015-04-30

    In this work, we collected radiation-damage-free data from a set of cryo-cooled crystals for a novel 30S ribosomal subunit mutant using goniometer-based femtosecond crystallography. Crystal quality assessment for these samples was conducted at the X-ray Pump Probe end-station of the Linac Coherent Light Source (LCLS) using recently introduced goniometer-based instrumentation. These 30S subunit crystals were genetically engineered to omit a 26-residue protein, Thx, which is present in the wild-type Thermus thermophilus 30S ribosomal subunit. We are primarily interested in elucidating the contribution of this ribosomal protein to the overall 30S subunit structure. To assess the viability of this study, femtosecond X-ray diffraction patterns from these crystals were recorded at the LCLS during a protein crystal screening beam time. During our data collection, we successfully observed diffraction from these difficult-to-grow 30S ribosomal subunit crystals. Most of our crystals were found to diffract to low resolution, while one crystal diffracted to 3.2 Å resolution. These data suggest the feasibility of pursuing high-resolution data collection as well as the need to improve sample preparation and handling in order to collect a complete radiation-damage-free data set using an X-ray Free Electron Laser.

  10. Goniometer-based femtosecond X-ray diffraction of mutant 30S ribosomal subunit crystals

    DOE PAGES

    Dao, E. Han; Sierra, Raymond G.; Laksmono, Hartawan; Lemke, Henrik T.; Alonso-Mori, Roberto; Coey, Aaron; Larsen, Kevin; Baxter, Elizabeth L.; Cohen, Aina E.; Soltis, S. Michael; et al

    2015-04-30

    In this work, we collected radiation-damage-free data from a set of cryo-cooled crystals for a novel 30S ribosomal subunit mutant using goniometer-based femtosecond crystallography. Crystal quality assessment for these samples was conducted at the X-ray Pump Probe end-station of the Linac Coherent Light Source (LCLS) using recently introduced goniometer-based instrumentation. These 30S subunit crystals were genetically engineered to omit a 26-residue protein, Thx, which is present in the wild-type Thermus thermophilus 30S ribosomal subunit. We are primarily interested in elucidating the contribution of this ribosomal protein to the overall 30S subunit structure. To assess the viability of this study, femtosecondmore » X-ray diffraction patterns from these crystals were recorded at the LCLS during a protein crystal screening beam time. During our data collection, we successfully observed diffraction from these difficult-to-grow 30S ribosomal subunit crystals. Most of our crystals were found to diffract to low resolution, while one crystal diffracted to 3.2 Å resolution. These data suggest the feasibility of pursuing high-resolution data collection as well as the need to improve sample preparation and handling in order to collect a complete radiation-damage-free data set using an X-ray Free Electron Laser.« less

  11. Model-based reconstruction for x-ray diffraction imaging

    NASA Astrophysics Data System (ADS)

    Sridhar, Venkatesh; Kisner, Sherman J.; Skatter, Sondre; Bouman, Charles A.

    2016-05-01

    In this paper, we propose a novel 4D model-based iterative reconstruction (MBIR) algorithm for low-angle scatter X-ray Diffraction (XRD) that can substantially increase the SNR. Our forward model is based on a Poisson photon counting model that incorporates a spatial point-spread function, detector energy response and energy-dependent attenuation correction. Our prior model uses a Markov random field (MRF) together with a reduced spectral bases set determined using non-negative matrix factorization. We demonstrate the effectiveness of our method with real data sets.

  12. Evaluation on double-wall-tube residual stress distribution of sodium-heated steam generator by neutron diffraction and numerical analysis

    SciTech Connect

    Kisohara, N.; Suzuki, H.; Akita, K.; Kasahara, N.

    2012-07-01

    A double-wall-tube is nominated for the steam generator heat transfer tube of future sodium fast reactors (SFRs) in Japan, to decrease the possibility of sodium/water reaction. The double-wall-tube consists of an inner tube and an outer tube, and they are mechanically contacted to keep the heat transfer of the interface between the inner and outer tubes by their residual stress. During long term SG operation, the contact stress at the interface gradually falls down due to stress relaxation. This phenomenon might increase the thermal resistance of the interface and degrade the tube heat transfer performance. The contact stress relaxation can be predicted by numerical analysis, and the analysis requires the data of the initial residual stress distributions in the tubes. However, unclear initial residual stress distributions prevent precious relaxation evaluation. In order to resolve this issue, a neutron diffraction method was employed to reveal the tri-axial (radius, hoop and longitudinal) initial residual stress distributions in the double-wall-tube. Strain gauges also were used to evaluate the contact stress. The measurement results were analyzed using a JAEA's structural computer code to determine the initial residual stress distributions. Based on the stress distributions, the structural computer code has predicted the transition of the relaxation and the decrease of the contact stress. The radial and longitudinal temperature distributions in the tubes were input to the structural analysis model. Since the radial thermal expansion difference between the inner (colder) and outer (hotter) tube reduces the contact stress and the tube inside steam pressure contributes to increasing it, the analytical model also took these effects into consideration. It has been conduced that the inner and outer tubes are contacted with sufficient stresses during the plant life time, and that effective heat transfer degradation dose not occur in the double-wall-tube SG. (authors)

  13. Neutron diffraction measurements for the determination of heat treatment effectiveness in generating compressive residual stress in an automotive crown gear

    NASA Astrophysics Data System (ADS)

    Albertini, G.; Bruno, G.; Fiori, F.; Girardin, E.; Giuliani, A.; Quadrini, E.; Romani, F.

    2000-03-01

    Thermal austenitizing and tempering treatments are being developed in automotive industry to prevent crack initiation and propagation, especially in components where stress intensity factors influence the stress field and ultimately the fatigue life of the component. This is the case of crown gears, where the tooth root typically undergoes impulsive and very high loads which frequently cause cracking if tensile residual stresses are present at the surface. The sign reversal of these stresses is the aim of austenitizing and tempering treatments. In this work neutron diffraction measurements of residual stress (RS) on a UNI55Cr3 steel crown gear, carried out at HMI-BENSC , are presented. The sample was submitted to a new multi-frequency induction technique whose effectiveness was checked. Comparisons with X-ray measurements are shown, and RS measured by X-rays on a similar shot-peened sample are also mentioned. Experiments at HMI-BENSC have received financial support by the European Commission under the TMR/LSF Access Programme (contract no. ERBFMGE CT950060).

  14. X-ray diffraction study of residual stresses in metal-matrix composite-jacketed steel cylinders subjected to internal pressure. Final report

    SciTech Connect

    Lee, S.L.; Doxbeck, M.; Capsimalis, G.

    1992-03-01

    The study of aluminum/silicon carbide metal matrix composite (MMC)-jacketed steel structural components was made because of their light weight and high stiffness. Steel 'liner' cylinders were wrapped with MMC 'jackets' with an all-hoop layup and put through various degrees of hydraulic autofrettage and thermal soak. In this report, the results from our x-ray diffraction residual stress measurements on cylinders using a position-sensitive scintillation detection system are discussed. Our experimental results are compared with theoretical predictions from a model based on the elastic-plastic analysis of a thick-walled cylinder subjected to internal pressure. Interpretation of the interference effect caused by the MMC jacket on the steel liner is also discussed.

  15. Demonstration of an intelligent hydrogel based diffraction grating

    NASA Astrophysics Data System (ADS)

    Zhang, R.; Bowyer, A.; Eisenthal, R.; Hubble, J.

    2005-05-01

    We report the fabrication of a diffraction grating cast into a responsive hydrogel using a silicone rubber intermediate cast from an engraved glass master grating. The aim to investigate if changes in the swelling of this gel in response to changes in the concentration of a specific analyte led to changes in the line spacing, and hence diffraction pattern, of the grating. The protocol for casting gratings was initially developed using a composite carboxymethyl dextran/bovine serum albumin gel produced using carbodiimide chemistry to assess the optimum gel properties required. Examination under a light microscope showed that, formed under appropriate synthesis conditions, CM-dextran-BSA hydrogels retained the grating structure and appeared to have similar optical properties to the silicon rubber sub-master used for casting. For a facile initial evaluation of the detection principle a number of similar gels were produced using cross-linked alginic acid. In this case excess carboxylic groups remaining after cross-linking were able to form additional ionic cross-links in the presence of divalent cations (Ca2+). Test experiments with these gels showed that both the size and position of the reflected and refracted spots obtained from illumination with a Helium-Neon laser changed as gel swelling changed with calcium ion concentration i.e. the size of both diffraction and reflection spots increased as the alginate hydrogel shrank in response to changes in environmental Ca2+. The utility of the alginate based gels for the detection of cations, together with evidence that dextran protein gels can retain grating structures, suggest that this assay procedure should applicable to any hydrogel where the response is based on protein-ligand interactions. The key requirement is that the cross-linking interactions constraining gel swelling can be quantitatively displaced by the analyte acting as a specific competitor.

  16. Diffraction-analysis-based characterization of very fine gratings

    NASA Astrophysics Data System (ADS)

    Bischoff, Joerg; Truckenbrodt, Horst; Bauer, Joachim J.

    1997-09-01

    Fine gratings with spatial periods below one micron, either ruled mechanically or patterned holographically, play a key role as encoders in high precision translational or rotational coordinate or measuring machines. Besides, the fast in-line characterization of submicron patterns is a stringent demand in recent microelectronic technology. Thus, a rapid, destruction free and highly accurate measuring technique is required to ensure the quality during manufacturing and for final testing. We propose an optical method which was already successfully introduced in semiconductor industry. Here, the inverse scatter problem inherent in this diffraction based approach is overcome by sophisticated data analysis such as multivariate regression or neural networks. Shortly sketched, the procedure is as follows: certain diffraction efficiencies are measured with an optical angle resolved scatterometer and assigned to a number of profile parameters via data analysis (prediction). Before, the specific measuring model has to be calibrated. If the wavelength-to-period rate is well below unity, it is quite easy to gather enough diffraction orders. However, for gratings with spatial periods being smaller than the probing wavelength, merely the specular reflex will propagate for perpendicular incidence (zero order grating). Consequently, it is virtually impossible to perform a regression analysis. A proper mean to tackle this bottleneck is to record the zero-order reflex as a function of the incident angle. In this paper, the measurement of submicron gratings is discussed with the examples of 0.8, 1.0 and 1.4 micron period resist gratings on silicon, etched silicon oxide on silicon (same periods) and a 512 nm pitch chromium grating on quartz. Using a He-Ne laser with 633 nm wavelength and measuring the direct reflex in both linear polarizations, it is shown that even submicron patterning processes can be monitored and the resulting profiles with linewidths below a half micron can be

  17. Residual stress mapping by micro X-ray diffraction: Application to the study of thin film buckling

    SciTech Connect

    Goudeau, P.; Villain, P.; Tamura, N.; Celestre, R.S.; Padmore, H.A.

    2002-11-06

    Thin films deposited by Physical Vapour Deposition techniques on substrates generally exhibit large residual stresses which may be responsible of spontaneous detachment of the film from its substrate and in the case of compressive stresses, thin film buckling. Although these effects are undesirable for future applications, one may take benefit of it for thin film mechanical properties investigation. Since the 80's, a lot of theoretical works have been done to develop mechanical models with the aim to get a better understanding of driven mechanisms giving rise to this phenomenon and thus to propose solutions to avoid such problems. Nevertheless, only a few experimental works have been done on this subject to support these theoretical results and nothing concerning local stress/strain measurement mainly because of the small dimension of the buckling (few tenth mm). This paper deals with the application of micro beam x-ray diffraction available on synchrotron radiation sources for stress/ strain mapping analysis of gold thin film buckling.

  18. Diffraction leveraged modulation of X-ray pulses using MEMS-based X-ray optics

    DOEpatents

    Lopez, Daniel; Shenoy, Gopal; Wang, Jin; Walko, Donald A.; Jung, Il-Woong; Mukhopadhyay, Deepkishore

    2016-08-09

    A method and apparatus are provided for implementing Bragg-diffraction leveraged modulation of X-ray pulses using MicroElectroMechanical systems (MEMS) based diffractive optics. An oscillating crystalline MEMS device generates a controllable time-window for diffraction of the incident X-ray radiation. The Bragg-diffraction leveraged modulation of X-ray pulses includes isolating a particular pulse, spatially separating individual pulses, and spreading a single pulse from an X-ray pulse-train.

  19. Large Diffractive Optics for GEo-Based Earth Surveillance

    SciTech Connect

    Hyde, R A

    2003-09-11

    in diameter, building ten-fold larger ones for GEO applications (let alone delivering and operating them there) presents major difficulties. However, since the challenges of fielding large platforms in GEO are matched by the benefits of continuous coverage, we propose a program to develop such optical platforms. In this section, we will examine a particular form of large aperture optic, using a flat diffractive lens instead of the more conventional curved reflectors considered elsewhere in this report. We will discuss both the development of this type of large aperture optics, as well as the steps necessary to use it for GEO-based Earth surveillance. In a later section of this report we will discuss another use for large diffractive optics, their application for global-reach laser weapons.

  20. Asymmetric diffraction based on a passive parity-time grating

    NASA Astrophysics Data System (ADS)

    Zhu, Xue-Yi; Xu, Ye-Long; Zou, Yi; Sun, Xiao-Chen; He, Cheng; Lu, Ming-Hui; Liu, Xiao-Ping; Chen, Yan-Feng

    2016-09-01

    Optical structures with balanced loss and gain provide an efficient platform to study the features of light propagation under non-Hermitian parity-time symmetry. Here, we report a feasible design of one-dimensional parity-time symmetric diffraction grating, where the real and imaginary parts of refractive index are separately modulated. Due to the spontaneous breaking of parity-time symmetry at the exceptional point, asymmetric diffractions are observed between a pair of oblique incident light. This asymmetric phenomenon, determined by the modulation direction of the introduced parity-time symmetry, is also polarization-dependent. The coupled-mode theory is implemented to theoretically analyze the polarization dependent asymmetric diffraction, showing consistence with numerical simulations. Our findings may provide a feasible way for manipulating light and instructively inspire the development of diffraction optics.

  1. Residual stress profiling in the ferrite and cementite phases of cold-drawn steel rods by synchrotron X-ray and neutron diffraction

    SciTech Connect

    Martinez-Perez, M.L.; Mompean, F.J.; Ruiz-Hervias, J.; Atienza, J.M.; Elices, M.; Peng Rulin; Buslaps, T.

    2004-10-18

    Residual stress profiles have been measured in the ferrite and cementite phases of a cold-drawn eutectoid steel rod by neutron and synchrotron X-ray diffraction in three orientations (axial, radial and hoop). Neutron diffraction was employed to measure the ferrite stresses, whereas synchrotron radiation was used for ferrite and cementite stresses. Experimental results in the ferrite phase showed excellent agreement between both experimental techniques when gauge volume effects were accounted for. Axial cementite stresses were always tensile, with a maximum value close to 1700 MPa at the rod surface. Radial and hoop cementite stresses were compressive along the diameter of the rod, with a minimum of -1900 MPa at the rod center. A 3D-finite element simulation of the macro residual stresses resulting from cold-drawing showed remarkable agreement with those determined from the experimental measurements in the ferrite and cementite phases.

  2. Experimental research on the multi-order acousto-optic diffraction based on Raman-Nath diffraction

    NASA Astrophysics Data System (ADS)

    Gu, Huadong; Shao, Zhongxing; Zheng, Chenqi; Yang, Jie; Chen, Ruitao; Gu, Zetong

    2015-03-01

    In this paper, the experimental investigation on the interaction length for getting the optimum diffraction of the multi-order acousto-optic diffraction is presented. Based on these results, the feasibility of acousto-optic Q-switch taking H2O or TeO2 as medium respectively for ultraviolet and visible lasers are discussed. The fact that the optimum interaction length tightly relies on the frequency of the sound and does not relate to the wavelength and power of the light is found in the experiment. The interaction length will become longer as the frequency of the ultrasound becomes higher. The interaction length is about 8mm when the acoustic frequency is at about 9MHz and becomes about 4mm at 6MHz. A Q-switch that works with pure water is designed and a total diffractive efficiency of about 98% was obtained under the condition that the acoustic frequency is 9MHz and the acoustic power is 3.4W. An acousto-optic Q-switch made of TeO2, in terms of Raman-Nath diffraction is designed. With a cooling system on the device, a total diffractive efficiency of about 75% is obtained under the condition that the acoustic frequency is 10MHz and the acoustic power is 10W. The loss by one path of the device is about 5% on the best condition. Then the modulated pulse width is measured as about 200ns on the condition that the acoustic frequency is 11MHz, the acoustic power is 6W and the repetition frequency is 10kHz.

  3. Iterative methods based upon residual averaging

    NASA Technical Reports Server (NTRS)

    Neuberger, J. W.

    1980-01-01

    Iterative methods for solving boundary value problems for systems of nonlinear partial differential equations are discussed. The methods involve subtracting an average of residuals from one approximation in order to arrive at a subsequent approximation. Two abstract methods in Hilbert space are given and application of these methods to quasilinear systems to give numerical schemes for such problems is demonstrated. Potential theoretic matters related to the iteration schemes are discussed.

  4. Twenty-meter space telescope based on diffractive Fresnel lens

    NASA Astrophysics Data System (ADS)

    Early, James T.; Hyde, Roderick; Baron, Richard L.

    2004-02-01

    Diffractive lenses offer two potential advantages for very large aperture space telescopes; very loose surface-figure tolerances and physical implementation as thin, flat optical elements. In order to actually realize these advantages one must be able to build large diffractive lenses with adequate optical precision and also to compactly stow the lens for launch and then fully deploy it in space. We will discuss the recent fabrication and assembly demonstration of a 5m glass diffractive Fresnel lens at LLNL. Optical performance data from smaller full telescopes with diffractive lens and corrective optics show diffraction limited performance with broad bandwidths. A systems design for a 20m space telescope will be presented. The primary optic can be rolled to fit inside of the standard fairings of the Delta IV vehicle. This configuration has a simple deployment and requires no orbital assembly. A twenty meter visible telescope could have a significant impact in conventional astronomy with eight times the resolution of Hubble and over sixty times the light gathering capacity. If the light scattering is made acceptable, this telescope could also be used in the search for terrestrial planets.

  5. Twenty Meter Space Telescope Based on Diffractive Fresnel Lens

    SciTech Connect

    Early, J; Hyde, R; Baron, R

    2003-06-26

    Diffractive lenses offer two potential advantages for very large aperture space telescopes; very loose surface-figure tolerances and physical implementation as thin, flat optical elements. In order to actually realize these advantages one must be able to build large diffractive lenses with adequate optical precision and also to compactly stow the lens for launch and then fully deploy it in space. We will discuss the recent fabrication and assembly demonstration of a 5m glass diffractive Fresnel lens at LLNL. Optical performance data from smaller full telescopes with diffractive lens and corrective optics show diffraction limited performance with broad bandwidths. A systems design for a 20m space telescope will be presented. The primary optic can be rolled to fit inside of the standard fairings of the Delta IV vehicle. This configuration has a simple deployment and requires no orbital assembly. A twenty meter visible telescope could have a significant impact in conventional astronomy with eight times the resolution of Hubble and over sixty times the light gathering capacity. If the light scattering is made acceptable, this telescope could also be used in the search for terrestrial planets.

  6. Residual stress mapping by micro X-ray diffraction: Application to the study of thin film buckling

    NASA Astrophysics Data System (ADS)

    Goudeau, P.; Villain, P.; Tamura, N.; Celestre, R. S.; Padmore, H.

    2002-07-01

    Thin films deposited by Physical Vapour Deposition techniques on substrates generally exhibit large residual stresses which may be responsible of spontaneous detachment of the film from its substrate and in the case of compressive stresses, thin film buckling. Although these effects are undesirable for future applications, one may take benefit of it for thin film mechanical properties investigation. Since the 80's, a lot of theoretical works have been done to develop mechanical models with the aim to get a better understanding of driven mechanisms giving rise to this phenomenon and thus to propose solutions to avoid such problems. Nevertheless, only a few experimental works have been done on this subject to support these theoretical results and nothing concerning local stress/strain measurement mainly because of the small dimension of the buckling (few tenth μm). This paper deals with the application of micro beam x-ray diffraction available on synchrotron radiation sources for stress/strain mapping analysis of gold thin film buckling. Les films minces déposés par des techniques de dépôt physique sous vide sur substrats présentent généralement des contraintes résiduelles très élevées qui peuvent être responsables du délaminage spontané du film et dans le cas de contraintes de compression, de l'apparition de cloques. Bien que ces décollements soient indésirables pour les applications technologiques futures, ils peuvent être mis à profit pour analyser les propriétés mécaniques locales dans ces systèmes. Depuis le début des années 80, un grand nombre d'études théoriques ont permis de développer des modèles dans le soucis de mieux comprendre ces phénomènes de flambage. Néanmoins, la validation de ces modèles repose sur une confrontation avec des études expérimentales qui demeurent jusqu'à présent très rares. Ainsi, les champs de déformations associés à ces structures de décollements n'ont pas été déterminés du fait

  7. Silica Nanowire Arrays for Diffraction-Based Bioaffinity Sensing

    PubMed Central

    Loget, Gabriel; Corn, Robert M.

    2014-01-01

    Arrays of electrodeposited silica nanowires (SiO2 NWs) have been fabricated over large areas (cm2) on fluoropolymer thin films attached to glass substrates by a combination of photolithography and electrochemically triggered sol-gel nanoscale deposition. Optical and SEM measurements revealed that the SiO2 NW arrays had an average spacing of 10 micrometers and an average width of 700 nm with a significant grain structure that was a result of the sol-gel deposition process. The optical diffraction properties at 633 nm of the SiO2 NWs arrays were characterized when placed in contact with solutions using a prism-coupled total internal reflection geometry; quantification of changes in these diffraction properties was applied in various sensing applications. Bulk refractive index sensing using the SiO2 NWs grating was demonstrated with a refractive index resolution of 1.30 × 10−5 RIU. Toposelectively chemically-modified SiO2 NW arrays were used for diffraction biosensing measurements of surface binding events, such as the electrostatic adsorption of gold nanoparticles and the bioaffinity adsorption of streptavidin onto a biotin monolayer. Finally, the application of the SiO2 NWs arrays for practical medical diagnostic applications was demonstrated by monitoring the diffraction of SiO2 NWs arrays functionalized with a single-stranded DNA aptamer in order to detect human α-thrombin from solutions at sub-pathologic nanomolar concentrations. PMID:24590560

  8. Layered holographic stereogram based on inverse Fresnel diffraction.

    PubMed

    Zhang, Hao; Zhao, Yan; Cao, Liangcai; Jin, Guofan

    2016-01-20

    We propose an efficient algorithm using layered holographic stereogram for three-dimensional (3D) computer-generated holograms. The hologram is spatially partitioned into multiple holographic elements (hogels) to provide the occlusion effect and motion parallax by use of multiple viewpoint rendering. Each hogel is calculated with inverse Fresnel diffraction by slicing the viewing frustum according to the depth image. The sliced layers can provide accurate depth cues for reconstruction since the geometric information of the 3D scene is faithfully matched. The algorithm is compatible with computer graphics rendering techniques and robust for holograms with different parameters. When the hogel size equals 1 mm, the signal-to-noise ratio of the diffraction calculation is above 39 dB with a propagation distance longer than 10 mm. Numerical simulations and optical experiments have demonstrated that the proposed method can reconstruct quality 3D images with reduced computational load. PMID:26835948

  9. Dedicated spectrometers based on diffractive optics: design, modelling and evaluation

    NASA Astrophysics Data System (ADS)

    Løvhaugen, O.; Johansen, I.-R.; Bakke, K. A. H.; Fismen, B. G.; Nicolas, S.

    The described design of diffractive optical elements for low cost IR-spectrometers gives a built-in wavelength reference and allows 'spectral arithmetic' to be implemented in the optical performance of the DOE. The diffractive element combines the function of the lenses and the grating and eliminates the need for alignment of those components in the standard scanned grating spectrometer design. The element gives out a set of foci, each with one spectral component, which are scanned across a detector, thus relaxing the demands for scan angle control. It can thus be regarded as an alternative solution to a beam splitter and band pass filter instrument. Software tools have been designed to ease the adaptation of the design to different applications. To model the performance of the spectrometers we have implemented a scalar Rayleigh-Sommerfeldt diffraction model. The gold-coated elements are produced by injection moulding using a compact disc (CD) moulding technique and mould inlays mastered by e-beam lithography. The optimized selection of wavelength bands and the classification of the measured signal use a combination of principal component analysis and robust statistical methods. Typical applications will be material characterization of recycled plastics and gas monitoring. Spectrometers for two different applications have been built and tested. Comparisons between the design goals and the measured performance have been made and show good agreements.

  10. High energy X-ray diffraction measurement of residual stresses in a monolithic aluminum clad uranium–10 wt% molybdenum fuel plate assembly

    SciTech Connect

    D. W. Brown; M. A. Okuniewski; J. D. Almer; L. Balogh; B. Clausen; J. S. Okasinski; B. H. Rabin

    2013-10-01

    Residual stresses are expected in monolithic, aluminum clad uranium 10 wt% molybdenum (U–10Mo) nuclear fuel plates because of the large mismatch in thermal expansion between the two bonded materials. The full residual stress tensor of the U–10Mo foil in a fuel plate assembly was mapped with 0.1 mm resolution using high-energy (86 keV) X-ray diffraction. The in-plane stresses in the U–10Mo foil are strongly compressive, roughly -250 MPa in the longitudinal direction and -140 MPa in the transverse direction near the center of the fuel foil. The normal component of the stress is weakly compressive near the center of the foil and tensile near the corner. The disparity in the residual stress between the two in-plane directions far from the edges and the tensile normal stress suggest that plastic deformation in the aluminum cladding during fabrication by hot isostatic pressing also contributes to the residual stress field. A tensile in-plane residual stress is presumed to be present in the aluminum cladding to balance the large in-plane compressive stresses in the U–10Mo fuel foil, but cannot be directly measured with the current technique due to large grain size.

  11. High energy X-ray diffraction measurement of residual stresses in a monolithic aluminum clad uranium-10 wt% molybdenum fuel plate assembly

    NASA Astrophysics Data System (ADS)

    Brown, D. W.; Okuniewski, M. A.; Almer, J. D.; Balogh, L.; Clausen, B.; Okasinski, J. S.; Rabin, B. H.

    2013-10-01

    Residual stresses are expected in monolithic, aluminum clad uranium 10 wt% molybdenum (U-10Mo) nuclear fuel plates because of the large mismatch in thermal expansion between the two bonded materials. The full residual stress tensor of the U-10Mo foil in a fuel plate assembly was mapped with 0.1 mm resolution using high-energy (86 keV) X-ray diffraction. The in-plane stresses in the U-10Mo foil are strongly compressive, roughly -250 MPa in the longitudinal direction and -140 MPa in the transverse direction near the center of the fuel foil. The normal component of the stress is weakly compressive near the center of the foil and tensile near the corner. The disparity in the residual stress between the two in-plane directions far from the edges and the tensile normal stress suggest that plastic deformation in the aluminum cladding during fabrication by hot isostatic pressing also contributes to the residual stress field. A tensile in-plane residual stress is presumed to be present in the aluminum cladding to balance the large in-plane compressive stresses in the U-10Mo fuel foil, but cannot be directly measured with the current technique due to large grain size.

  12. Three-dimensional welding residual stresses evaluation based on the eigenstrain methodology via X-ray measurements at the surface

    NASA Astrophysics Data System (ADS)

    Ogawa, Masaru

    2014-12-01

    In order to assure structural integrity for operating welded structures, it is necessary to evaluate crack growth rate and crack propagation direction for each observed crack non-destructively. Here, three dimensional (3D) welding residual stresses must be evaluated to predict crack propagation. Today, X-ray diffraction is used and the ultrasonic method has been proposed as non-destructive method to measure residual stresses. However, it is impossible to determine residual stress distributions in the thickness direction. Although residual stresses through a depth of several tens of millimeters can be evaluated non-destructively by neutron diffraction, it cannot be used as an on-site measurement technique. This is because neutron diffraction is only available in special irradiation facilities. Author pays attention to the bead flush method based on the eigenstrain methodology. In this method, 3D welding residual stresses are calculated by an elastic Finite Element Method (FEM) analysis from eigenstrains which are evaluated by an inverse analysis from released strains by strain gauges in the removal of the reinforcement of the weld. Here, the removal of the excess metal can be regarded as non-destructive treatment because toe of weld which may become crack starters can be eliminated. The effectiveness of the method has been proven for welded plates and pipes even with relatively lower bead height. In actual measurements, stress evaluation accuracy becomes poorer because measured values of strain gauges are affected by processing strains on the machined surface. In the previous studies, the author has developed the bead flush method that is free from the influence of the affecting strains by using residual strains on surface by X-ray diffraction. However, stress evaluation accuracy is not good enough because of relatively poor measurement accuracy of X-ray diffraction. In this study, a method to improve the estimation accuracy of residual stresses in this method is

  13. Determination and mitigation of the uncertainty of neutron diffraction measurements of residual strain in large-grained polycrystalline material

    PubMed Central

    Holden, Tom M.; Traore, Yeli; James, Jon; Kelleher, Joe; Bouchard, P. John

    2015-01-01

    For large-grained samples it is advantageous to perform pairs of neutron diffraction measurements at the same spatial location but rotated 180° around the geometric centre of the gauge volume as a means of minimizing the scatter coming from the random positioning of grains within the gauge volume. PMID:25844082

  14. Non destructive neutron diffraction measurements of cavities, inhomogeneities, and residual strain in bronzes of Ghiberti's relief from the Gates of Paradise

    SciTech Connect

    Festa, G.; Senesi, R.; Alessandroni, M.; Andreani, C.; Vitali, G.; Porcinai, S.; Giusti, A. M.; Materna, T.; Paradowska, A. M.

    2011-03-15

    Quantitative neutron studies of cultural heritage objects provide access to microscopic, mesoscopic, and macroscopic structures in a nondestructive manner. In this paper we present a neutron diffraction investigation of a Ghiberti Renaissance gilded bronze relief devoted to the measurement of cavities and inhomogeneities in the bulk of the sample, along with the bulk phase composition and residual strain distribution. The quantitative measurements allowed the determination of the re-melting parts extension, as well as improving current knowledge about the manufacturing process. The study provides significant and unique information to conservators and restorators about the history of the relief.

  15. Comparison of Brazed Residual Stress and Thermal Deformation between X-Type and Pyramidal Lattice Truss Sandwich Structure: Neutron Diffraction Measurement and Simulation Study

    NASA Astrophysics Data System (ADS)

    Jiang, Wenchun; Wei, Zhiquan; Luo, Yun; Zhang, Weiya; Woo, Wanchuck

    2016-06-01

    This paper uses finite element method and neutron diffraction measurement to study the residual stress in lattice truss sandwich structure. A comparison of residual stress and thermal deformation between X-type and pyramidal lattice truss sandwich structure has been carried out. The residual stresses are concentrated in the middle joint and then decreases gradually to both the ends. The residual stresses in the X-type lattice truss sandwich structure are smaller than those in pyramidal structure. The maximum longitudinal and transverse stresses of pyramidal structure are 220 and 202 MPa, respectively, but they decrease to 190 and 145 MPa for X-type lattice truss sandwich structure, respectively. The thermal deformation for lattice truss sandwich panel structure is of wave shape. The X-type has a better resistance to thermal deformation than pyramidal lattice truss sandwich structure. The maximum wave deformation of pyramidal structure (0.02 mm) is about twice as that of X-type (0.01 mm) at the same brazing condition.

  16. Characterization of residual stresses in Eurofer welded specimens: Measurements by neutron diffraction and comparison with weld modeling

    NASA Astrophysics Data System (ADS)

    Coppola, R.; Asserin, O.; Aubert, P.; Braham, C.; Monnier, A.; Valli, M.; Diegele, E.

    2011-10-01

    The stress field of a dual-beam laser weld on a Eurofer-97 model plate has been experimentally determined by neutron diffraction measurements. The measurements were carried out at the ILL-Grenoble, in the three principal directions, at different distances from the weld and inside the weld itself. In the longitudinal direction, the most relevant for technical applications, there is good agreement between these experimental results and results obtained by finite element numerical methods: tensile stresses as high as 750 MPa are found inside the weld, rapidly decreasing with increasing distance from the weld centre. In the two other directions the agreement between experimentally determined and calculated stresses is still good far from the weld; inside the weld the experimental data are affected by the strong texture detected by X-ray diffraction, possibly produced by the heating and subsequent cooling of the structure.

  17. Microcontroller based spectrophotometer using compact disc as diffraction grid

    NASA Astrophysics Data System (ADS)

    Bano, Saleha; Altaf, Talat; Akbar, Sunila

    2010-12-01

    This paper describes the design and implementation of a portable, inexpensive and cost effective spectrophotometer. The device combines the use of compact disc (CD) media as diffraction grid and 60 watt bulb as a light source. Moreover it employs a moving slit along with stepper motor for obtaining a monochromatic light, photocell with spectral sensitivity in visible region to determine the intensity of light and an amplifier with a very high gain as well as an advanced virtual RISC (AVR) microcontroller ATmega32 as a control unit. The device was successfully applied to determine the absorbance and transmittance of KMnO4 and the unknown concentration of KMnO4 with the help of calibration curve. For comparison purpose a commercial spectrophotometer was used. There are not significant differences between the absorbance and transmittance values estimated by the two instruments. Furthermore, good results are obtained at all visible wavelengths of light. Therefore, the designed instrument offers an economically feasible alternative for spectrophotometric sample analysis in small routine, research and teaching laboratories, because the components used in the designing of the device are cheap and of easy acquisition.

  18. Prospect for application of compact accelerator-based neutron source to neutron engineering diffraction

    NASA Astrophysics Data System (ADS)

    Ikeda, Yoshimasa; Taketani, Atsushi; Takamura, Masato; Sunaga, Hideyuki; Kumagai, Masayoshi; Oba, Yojiro; Otake, Yoshie; Suzuki, Hiroshi

    2016-10-01

    A compact accelerator-based neutron source has been lately discussed on engineering applications such as transmission imaging and small angle scattering as well as reflectometry. However, nobody considers using it for neutron diffraction experiment because of its low neutron flux. In this study, therefore, the neutron diffraction experiments are carried out using Riken Accelerator-driven Compact Neutron Source (RANS), to clarify the capability of the compact neutron source for neutron engineering diffraction. The diffraction pattern from a ferritic steel was successfully measured by suitable arrangement of the optical system to reduce the background noise, and it was confirmed that the recognizable diffraction pattern can be measured by a large sampling volume with 10 mm in cubic for an acceptable measurement time, i.e. 10 min. The minimum resolution of the 110 reflection for RANS is approximately 2.5% at 8 μs of the proton pulse width, which is insufficient to perform the strain measurement by neutron diffraction. The moderation time width at the wavelength corresponding to the 110 reflection is estimated to be approximately 30 μs, which is the most dominant factor to determine the resolution. Therefore, refinements of the moderator system to decrease the moderation time by decreasing a thickness of the moderator or by applying the decoupler system or application of the angular dispersive neutron diffraction technique are important to improve the resolution of the diffraction experiment using the compact neutron source. In contrast, the texture evolution due to plastic deformation was successfully observed by measuring a change in the diffraction peak intensity by RANS. Furthermore, the volume fraction of the austenitic phase in the dual phase mock specimen was also successfully evaluated by fitting the diffraction pattern using a Rietveld code. Consequently, RANS has been proved to be capable for neutron engineering diffraction aiming for the easy access

  19. Selenium Adsorption To Aluminum-Based Water Treatment Residuals

    EPA Science Inventory

    Aluminum-based water treatment residuals (WTR) can adsorb water-and soil-borne P, As(V), As(III), and perchlorate, and may be able to adsorb excess environmental selenium. WTR, clay minerals, and amorphous aluminum hydroxide were shaken for 24 hours in selenate or selenite solut...

  20. Selenium adsorption to aluminum-based water treatment residuals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aluminum-based water treatment residuals (WTR) can adsorb water- and soil-borne P, As(V), As(III), and perchlorate, and may be able to adsorb excess environmental selenium. WTR, clay minerals, and amorphous aluminum hydroxide were shaken for 24 hours in selenate or selenite solutions at pH values o...

  1. Neutron Diffraction Measurement of Residual Stresses, Dislocation Density and Texture in Zr-bonded U-10Mo ''Mini'' Fuel Foils and Plates

    SciTech Connect

    Brown, Donald W.; Okuniewski, M. A.; Sisneros, Thomas A.; Clausen, Bjorn; Moore, G. A.; Balogh, L

    2014-08-07

    Aluminum clad monolithic uranium 10 weight percent molybdenum (U-10Mo) fuel plates are being considered for conversion of several research and test nuclear reactors from high-enriched to low-enriched uranium fuel due to the inherently high density of fissile material. Comprehensive neutron diffraction measurements of the evolution of the textures, residual phase stresses, and dislocation densities in the individual phases of the mini-foils throughout several processing steps and following hot-isostatic pressing to the Al cladding, have been completed. Recovery and recrystallization of the bare U-10Mo fuel foil, as indicated by the dislocation density and texture, are observed depending on the state of the material prior to annealing and the duration and temperature of the annealing process. In general, the HIP procedure significantly reduces the dislocation density, but the final state of the clad plate, both texture and dislocation density, depends strongly on the final processing step of the fuel foil. In contrast, the residual stresses in the clad fuel plate do not depend strongly on the final processing step of the bare foil prior to HIP bonding. Rather, the residual stresses are dominated by the thermal expansion mismatch of the constituent materials of the fuel plate.

  2. Diffractive optics based on modulated subwavelength-domain V-ridge gratings

    NASA Astrophysics Data System (ADS)

    Bose, Gaurav; Verhoeven, Antonie; Vartiainen, Ismo; Roussey, Matthieu; Kuittinen, Markku; Tervo, Jani; Turunen, Jari

    2016-08-01

    We study the properties of reflection-type V-ridge gratings in the subwavelength domain and describe a method to realize diffractive optical elements by using such gratings as signal carriers. In particular, we utilize a coding scheme based on position modulation of a high-frequency V-ridge carrier grating. We design and demonstrate beam splitting elements using this coding scheme, electron-beam lithography, anisotropic wet etching of silicon, hot embossing of polymer, and metal deposition. These elements have the outstanding property of operating over a large spectral range from 406 to 520 nm. The measured diffraction patterns show excellent agreement with theoretical results given by rigorous diffraction theory.

  3. Folding simulations of alanine-based peptides with lysine residues.

    PubMed Central

    Sung, S S

    1995-01-01

    The folding of short alanine-based peptides with different numbers of lysine residues is simulated at constant temperature (274 K) using the rigid-element Monte Carlo method. The solvent-referenced potential has prevented the multiple-minima problem in helix folding. From various initial structures, the peptides with three lysine residues fold into helix-dominated conformations with the calculated average helicity in the range of 60-80%. The peptide with six lysine residues shows only 8-14% helicity. These results agree well with experimental observations. The intramolecular electrostatic interaction of the charged lysine side chains and their electrostatic hydration destabilize the helical conformations of the peptide with six lysine residues, whereas these effects on the peptides with three lysine residues are small. The simulations provide insight into the helix-folding mechanism, including the beta-bend intermediate in helix initiation, the (i, i + 3) hydrogen bonds, the asymmetrical helix propagation, and the asymmetrical helicities in the N- and C-terminal regions. These findings are consistent with previous studies. PMID:7756550

  4. Residual stress determination from a laser-based curvature measurement

    SciTech Connect

    W. D. Swank; R. A. Gavalya; J. K. Wright; R. N. Wright

    2000-05-08

    Thermally sprayed coating characteristics and mechanical properties are in part a result of the residual stress developed during the fabrication process. The total stress state in a coating/substrate is comprised of the quench stress and the coefficient of thermal expansion (CTE) mismatch stress. The quench stress is developed when molten particles impact the substrate and rapidly cool and solidify. The CTE mismatch stress results from a large difference in the thermal expansion coefficients of the coating and substrate material. It comes into effect when the substrate/coating combination cools from the equilibrated deposit temperature to room temperature. This paper describes a laser-based technique for measuring the curvature of a coated substrate and the analysis required to determine residual stress from curvature measurements. Quench stresses were determined by heating the specimen back to the deposit temperature thus removing the CTE mismatch stress. By subtracting the quench stress from the total residual stress at room temperature, the CTE mismatch stress was estimated. Residual stress measurements for thick (>1mm) spinel coatings with a Ni-Al bond coat on 304 stainless steel substrates were made. It was determined that a significant portion of the residual stress results from the quenching stress of the bond coat and that the spinel coating produces a larger CTE mismatch stress than quench stress.

  5. Residual Stress Determination from a Laser-Based Curvature Measurement

    SciTech Connect

    Swank, William David; Gavalya, Rick Allen; Wright, Julie Knibloe; Wright, Richard Neil

    2000-05-01

    Thermally sprayed coating characteristics and mechanical properties are in part a result of the residual stress developed during the fabrication process. The total stress state in a coating/substrate is comprised of the quench stress and the coefficient of thermal expansion (CTE) mismatch stress. The quench stress is developed when molten particles impact the substrate and rapidly cool and solidify. The CTE mismatch stress results from a large difference in the thermal expansion coefficients of the coating and substrate material. It comes into effect when the substrate/coating combination cools from the equilibrated deposit temperature to room temperature. This paper describes a laser-based technique for measuring the curvature of a coated substrate and the analysis required to determine residual stress from curvature measurements. Quench stresses were determined by heating the specimen back to the deposit temperature thus removing the CTE mismatch stress. By subtracting the quench stress from the total residual stress at room temperature, the CTE mismatch stress was estimated. Residual stress measurements for thick (>1mm) spinel coatings with a Ni-Al bond coat on 304 stainless steel substrates were made. It was determined that a significant portion of the residual stress results from the quenching stress of the bond coat and that the spinel coating produces a larger CTE mismatch stress than quench stress.

  6. An OFDM-Based Speech Encryption System without Residual Intelligibility

    NASA Astrophysics Data System (ADS)

    Tseng, Der-Chang; Chiu, Jung-Hui

    Since an FFT-based speech encryption system retains a considerable residual intelligibility, such as talk spurts and the original intonation in the encrypted speech, this makes it easy for eavesdroppers to deduce the information contents from the encrypted speech. In this letter, we propose a new technique based on the combination of an orthogonal frequency division multiplexing (OFDM) scheme and an appropriate QAM mapping method to remove the residual intelligibility from the encrypted speech by permuting several frequency components. In addition, the proposed OFDM-based speech encryption system needs only two FFT operations instead of the four required by the FFT-based speech encryption system. Simulation results are presented to show the effectiveness of this proposed technique.

  7. Residuals and the Residual-Based Statistic for Testing Goodness of Fit of Structural Equation Models

    ERIC Educational Resources Information Center

    Foldnes, Njal; Foss, Tron; Olsson, Ulf Henning

    2012-01-01

    The residuals obtained from fitting a structural equation model are crucial ingredients in obtaining chi-square goodness-of-fit statistics for the model. The authors present a didactic discussion of the residuals, obtaining a geometrical interpretation by recognizing the residuals as the result of oblique projections. This sheds light on the…

  8. Neutron diffraction measurement of residual stresses, dislocation density and texture in Zr-bonded U-10Mo “mini” fuel foils and plates

    DOE PAGES

    Brown, Donald William; Okuniewski, Maria A.; Sisneros, Thomas A.; Clausen, Bjorn; Moore, Glenn A.; Balogh, Levente

    2016-09-22

    Here, Al clad U-10Mo fuel plates are being considered for conversion of several research reactors from high-enriched to low-enriched U fuel. Neutron diffraction measurements of the textures, residual phase stresses, and dislocation densities in the individual phases of the mini-foils throughout several processing steps and following hot-isostatic pressing to the Al cladding, have been completed. Recovery and recrystallization of the bare U-10Mo fuel foil, as indicated by the dislocation density and texture, are observed depending on the state of the material prior to annealing and the duration and temperature of the annealing process. In general, the cladding procedure significantly reducesmore » the dislocation density, but the final state of the clad plate, both texture and dislocation density, depends strongly on the final processing step of the fuel foil. In contrast, the residual stress state of the final plate is dominated by the thermal expansion mismatch of the constituent materials.« less

  9. The nature of light: a description of photon diffraction based upon virtual particle exchange

    NASA Astrophysics Data System (ADS)

    Mobley, Michael J.

    2005-08-01

    Any discussion of the nature of light must include a reminder that whenever we make the observation of light (photons), we only observe particle-like properties. This paper provides a reiteration that we don"t need wave-like properties to scattered photons to describe phenomena such as diffraction or refraction of light. This paper updates the original ideas of Duane, later revived by Lande, which provided a description of light diffraction without making reference to a wave nature. These are updated using terminology more common to quantum electrodynamics which describes the interaction of particles in terms of the exchange of virtual photons. Diffraction is described in terms of an ensemble of distinct, probability weighted paths for the scattered photons. The scattering associated with each path results from the quantized momentum exchange with the scattering lattice attributed to the exchange or reflection of virtual photons. The probability for virtual particle exchange/reflection is dependent upon the allowed momentum states of the lattice determined by a Fourier analysis of the lattice geometry. Any scattered photon will exhibit an apparent wavelength inversely proportional to its momentum. Simplified, particle-like descriptions are developed for Young"s double slit diffraction, Fraunhofer diffraction and Fresnel diffraction. This description directly accounts for the quantization of momentum transferred to the scattering lattice and the specific eigenvalues of the lattice based upon the constraints to virtual photon exchange set by the Uncertainty Principle, Δπi = h/ζi.

  10. Leaching characteristics of calcium-based compounds in MSWI Residues: From the viewpoint of clogging risk.

    PubMed

    Xia, Yi; Zhang, Hua; Phoungthong, Khamphe; Shi, Dong-Xiao; Shen, Wen-Hui; Shao, Li-Ming; He, Pin-Jing

    2015-08-01

    Leachate collection system (LCS) clogging caused by calcium precipitation would be disadvantageous to landfill stability and operation. Meanwhile, calcium-based compounds are the main constituents in both municipal solid waste incineration bottom ash (MSWIBA) and stabilized air pollution control residues (SAPCR), which would increase the risk of LCS clogging once these calcium-rich residues were disposed in landfills. The leaching behaviors of calcium from the four compounds and municipal solid waste incineration (MSWI) residues were studied, and the influencing factors on leaching were discussed. The results showed that pH was the crucial factor in the calcium leaching process. CaCO3 and CaSiO3 began leaching when the leachate pH decreased to less than 7 and 10, respectively, while Ca3(PO4)2 leached at pH<12. CaSO4 could hardly dissolve in the experimental conditions. Moreover, the sequence of the leaching rate for the different calcium-based compounds is as follows: CaSiO3>Ca3(PO4)2>CaCO3. The calcium leaching from the MSWIBA and SAPCR separately started from pH<7 and pH<12, resulting from CaCO3 and Ca3(PO4)2 leaching respectively, which was proven by the X-ray diffraction results. Based on the leaching characteristics of the different calcium compounds and the mineral phase of calcium in the incineration residues, simulated computation of their clogging potential was conducted, providing the theoretical basis for the risk assessment pertaining to LCS clogging in landfills. PMID:25934218

  11. Leaching characteristics of calcium-based compounds in MSWI Residues: From the viewpoint of clogging risk

    SciTech Connect

    Xia, Yi; Zhang, Hua; Phoungthong, Khamphe; Shi, Dong-Xiao; Shen, Wen-Hui; Shao, Li-Ming; He, Pin-Jing

    2015-08-15

    Highlights: • The leaching behavior of Ca-based compounds commonly in MSWI residues was studied. • pH is the crucial factor for calcium leaching process. • CaCO{sub 3} was the most sensitive to leaching temperature and Ca{sub 3}(PO{sub 4}){sub 2} was the least. • Ca leaching of MSWIBA and SAPCR attributed to CaCO{sub 3} and Ca{sub 3}(PO{sub 4}){sub 2} respectively. • Potential clogging ability of MSWI residues leachate in open air was calculated. - Abstract: Leachate collection system (LCS) clogging caused by calcium precipitation would be disadvantageous to landfill stability and operation. Meanwhile, calcium-based compounds are the main constituents in both municipal solid waste incineration bottom ash (MSWIBA) and stabilized air pollution control residues (SAPCR), which would increase the risk of LCS clogging once these calcium-rich residues were disposed in landfills. The leaching behaviors of calcium from the four compounds and municipal solid waste incineration (MSWI) residues were studied, and the influencing factors on leaching were discussed. The results showed that pH was the crucial factor in the calcium leaching process. CaCO{sub 3} and CaSiO{sub 3} began leaching when the leachate pH decreased to less than 7 and 10, respectively, while Ca{sub 3}(PO{sub 4}){sub 2} leached at pH < 12. CaSO{sub 4} could hardly dissolve in the experimental conditions. Moreover, the sequence of the leaching rate for the different calcium-based compounds is as follows: CaSiO{sub 3} > Ca{sub 3}(PO{sub 4}){sub 2} > CaCO{sub 3}. The calcium leaching from the MSWIBA and SAPCR separately started from pH < 7 and pH < 12, resulting from CaCO{sub 3} and Ca{sub 3}(PO{sub 4}){sub 2} leaching respectively, which was proven by the X-ray diffraction results. Based on the leaching characteristics of the different calcium compounds and the mineral phase of calcium in the incineration residues, simulated computation of their clogging potential was conducted, providing the

  12. Optical double-image cryptography based on diffractive imaging with a laterally-translated phase grating.

    PubMed

    Chen, Wen; Chen, Xudong; Sheppard, Colin J R

    2011-10-10

    In this paper, we propose a method using structured-illumination-based diffractive imaging with a laterally-translated phase grating for optical double-image cryptography. An optical cryptosystem is designed, and multiple random phase-only masks are placed in the optical path. When a phase grating is laterally translated just before the plaintexts, several diffraction intensity patterns (i.e., ciphertexts) can be correspondingly obtained. During image decryption, an iterative retrieval algorithm is developed to extract plaintexts from the ciphertexts. In addition, security and advantages of the proposed method are analyzed. Feasibility and effectiveness of the proposed method are demonstrated by numerical simulation results.

  13. Digital micro-mirror device-based detector for particle-sizing instruments via Fraunhofer diffraction.

    PubMed

    Zhou, Jiayi; Cao, Zhang; Xie, Heng; Xu, Lijun

    2015-06-20

    In this paper, a digital micro-mirror device (DMD)-based detector is proposed for the detection of light intensity in particle-sizing instruments using Fraunhofer diffraction. The detector consists of only one photodiode, which eliminates the distortions caused by the nonuniformity of the detector arrays used in traditional instruments. The center of the diffraction pattern was accurately located to distribute the optimized arc-shaped mirror arrays for the intensity detection. Both simulated and experimental results showed that the proposed detector was superior to the classical one as it was less sensitive to noise than the detector arrays used in traditional systems.

  14. Fatigue investigations of autofrettaged steel cylinders based on neutron-diffraction measurements

    NASA Astrophysics Data System (ADS)

    de Swardt, R. R.; Venter, A. M.; van der Watt, M. W.

    A series of cyclic internal pressurization fatigue experiments was conducted on partially autofrettaged cylinders with multiple internal radial elliptic shaped cracks covering a wide range of possible configurations. A theoretical model was developed to predict the theoretical fatigue life using as input data the actual measured position of the plastic boundary from neutron-diffraction measurements on the failed specimens, as well as a position calculated analytically from the autofrettage pressure. The theoretical fatigue-life predictions based on the neutron-diffraction results were found to give the best correlation with experimental fatigue results.

  15. Imaging regenerating bone tissue based on neural networks applied to micro-diffraction measurements

    SciTech Connect

    Campi, G.; Pezzotti, G.; Fratini, M.; Ricci, A.; Burghammer, M.; Cancedda, R.; Mastrogiacomo, M.; Bukreeva, I.; Cedola, A.

    2013-12-16

    We monitored bone regeneration in a tissue engineering approach. To visualize and understand the structural evolution, the samples have been measured by X-ray micro-diffraction. We find that bone tissue regeneration proceeds through a multi-step mechanism, each step providing a specific diffraction signal. The large amount of data have been classified according to their structure and associated to the process they came from combining Neural Networks algorithms with least square pattern analysis. In this way, we obtain spatial maps of the different components of the tissues visualizing the complex kinetic at the base of the bone regeneration.

  16. Zonal representation-based residual-wavefront reconstruction using multiframe Shack-Hartmann measurements

    NASA Astrophysics Data System (ADS)

    Guo, Shiping; Zhang, Rongzhi; Li, Jisheng; Zou, Jianhua; Xu, Rong; Liu, Changhai

    2015-11-01

    Atmospheric turbulence-induced wavefront deformation can be only partially corrected by adaptive optics (AO) techniques in astronomical or artificial space object imaging; an accurate estimation of the residual-wavefront phase is still needed to approach the diffraction-limited resolution. The discrete phase gradients measured by Shack-Hartmann wavefront sensors (SHWFS) can help with the estimation. In this study, we build a dynamic average slopes measurement model for SHWFS in short-exposure AO images postprocessing; the proposed model is based on a zonal representation of the wavefront phase using Bernstein basis polynomials instead of the traditional Zernike modal expansion. Further, the turbulence's frozen flow hypothesis is adopted to update the initial model using multiframe SHWFS measurement data to achieve a more accurate reconstruction. Numerical experiments show the reconstruction errors significantly decrease even in poor seeing conditions, and show that our method is less sensitive to different SHWFS measurement noise levels.

  17. Single-order transmission diffraction gratings based on dispersion engineered all-dielectric metasurfaces

    NASA Astrophysics Data System (ADS)

    Gupta, Shulabh

    2016-08-01

    A single-order transmission diffraction grating based on dispersion engineered all-dielectric metasurfaces is proposed and its wavelength discriminating properties have been theoretically described and confirmed using numerical simulations. The metasurface is designed using a 2D array of all-dielectric resonators, which emulates a Huygens source configuration to achieve a perfect match to free-space in broad bandwidth. Using a holey dielectric nanodisk structure as the unit cell, the resonant wavelength is tapered across the metasurface to engineer the wavelength dependent spatial phase gradient, to emulate a dispersive prism. Consequently, different wavelengths are steered towards different directions and thus are discriminated on the output image plane. Due to subwavelength periodicities involved, the wavelength discrimination is achieved directly in the zeroth diffraction order of the device, unlike conventional diffraction gratings, thereby providing a high efficiency wavelength discriminating device.

  18. Single-order transmission diffraction gratings based on dispersion engineered all-dielectric metasurfaces.

    PubMed

    Gupta, Shulabh

    2016-08-01

    A single-order transmission diffraction grating based on dispersion engineered all-dielectric metasurfaces is proposed, and its wavelength discriminating properties have been theoretically described and confirmed using numerical simulations. The metasurface is designed using a 2D array of all-dielectric resonators, which emulates a Huygens' source configuration to achieve a perfect match to free space in broad bandwidth. Using a holey dielectric nanodisk structure as the unit cell, the resonant wavelength is tapered across the metasurface to engineer the wavelength-dependent spatial phase gradient, to emulate a dispersive prism. Consequently, different wavelengths are steered toward different directions and thus are discriminated on the output image plane. Due to the subwavelength periodicities involved, wavelength discrimination is achieved directly in the zeroth diffraction order of the device, unlike conventional diffraction gratings, thereby providing a high-efficiency wavelength discriminating device. PMID:27505664

  19. Single-order transmission diffraction gratings based on dispersion engineered all-dielectric metasurfaces.

    PubMed

    Gupta, Shulabh

    2016-08-01

    A single-order transmission diffraction grating based on dispersion engineered all-dielectric metasurfaces is proposed, and its wavelength discriminating properties have been theoretically described and confirmed using numerical simulations. The metasurface is designed using a 2D array of all-dielectric resonators, which emulates a Huygens' source configuration to achieve a perfect match to free space in broad bandwidth. Using a holey dielectric nanodisk structure as the unit cell, the resonant wavelength is tapered across the metasurface to engineer the wavelength-dependent spatial phase gradient, to emulate a dispersive prism. Consequently, different wavelengths are steered toward different directions and thus are discriminated on the output image plane. Due to the subwavelength periodicities involved, wavelength discrimination is achieved directly in the zeroth diffraction order of the device, unlike conventional diffraction gratings, thereby providing a high-efficiency wavelength discriminating device.

  20. Wave-optical analysis of parallax-image generation based on multiple diffraction gratings.

    PubMed

    Jang, Jae-Young; Ser, Jang-Il; Kim, Eun-Soo

    2013-06-01

    We propose an approach to generate as many parallax images (PIs) having different viewpoints of a 3-D object as required by use of multiple diffraction gratings (MDG) and confirm its feasibility through theoretical analysis and optical experiments. Here, the PIs generated from the MDG are derived as a convolution integral between the scaled object intensity and each δ-function array of m number of diffraction gratings based on wave-optics, which means the total number of PIs and viewpoints to be generated with the MDG may increase with the mth power of that generated with the single diffraction grating. In addition, optical experiments show that the number of PIs for the case of m=2 has been increased up to the second power of that for the case of m=1, which may validate the theoretical analysis and confirm its feasibility in the practical application.

  1. Quantitation of residual mouse DNA in monoclonal antibody based products.

    PubMed

    Per, S R; Aversa, C R; Sito, A F

    1990-01-01

    The identification and characterization of cell substrates and testing of bulk and final products is an important issue which must be addressed by manufacturers. In view of the fact that hundreds of applications for Investigational New Drugs (IND) have been submitted over the past few years, there is an obvious need for testing of these products. Detection of DNA by molecular hybridization has been used for various applications including the quantitation and characterization of DNA in biological products. We have developed a precise assay based on hybridization for the detection and quantitation of residual genomic DNA. In order to reduce protein interference, a specific pretreatment method for isolation of DNA in monoclonal antibody based products was implemented. We have used the assay to evaluate levels of contaminating DNA in prepared lots of monoclonal antibodies. Validation experiments demonstrated a sensitivity below 10 pg DNA using nick-translated 32P-labelled genomic DNA probes. The assay allows accurate quantitation of residual DNA in biologics.

  2. Diffraction based phase compensation method for phase-only liquid crystal on silicon devices in operation.

    PubMed

    Zhang, Zichen; Yang, Haining; Robertson, Brian; Redmond, Maura; Pivnenko, Mike; Collings, Neil; Crossland, William A; Chu, Daping

    2012-06-10

    A method to measure the optical response across the surface of a phase-only liquid crystal on silicon device using binary phase gratings is described together with a procedure to compensate its spatial optical phase variation. As a result, the residual power between zero and the minima of the first diffraction order for a binary grating can be reduced by more than 10 dB, from -15.98 dB to -26.29 dB. This phase compensation method is also shown to be useful in nonbinary cases. A reduction in the worst crosstalk by 5.32 dB can be achieved when quantized blazed gratings are used. PMID:22695663

  3. Precession electron diffraction assisted orientation mapping of gradient nanostructure in a Ni-based superalloy

    NASA Astrophysics Data System (ADS)

    Feng, Z. Q.; Chen, Y. X.; Wu, G. L.; Yang, Y. Q.

    2015-08-01

    Surface mechanical grinding of a Ni-based superalloy can introduce a gradient microstructure in the surface layer with a grain size from nanoscale to microscale. In-depth investigation of the crystal orientation distribution of the surface nanostructured layer is more often, however, not an easy work by using the scanning electron microscope (SEM) based electron backscatter diffraction (EBSD) method due to its sensitivity to lattice distortions and spatial resolution limitation. Here we use a newly developed precession electron diffraction (PED) technique coupled with transmission electron microscopy (TEM) to investigate the microstructural and crystallographic characteristics of the surface gradient nanostructure, with particular emphasis on the topmost nanocrystalline layer. A strong shear texture and a minor Copper texture were identified according to orientation analyses of the 1.6 pm thick near-surface nanocrystalline layer. The PED technique is proved to be practical for two dimensional orientation mapping of severely deformed microstructures at the nanoscale.

  4. Change of calibration of diffraction-based particle sizers in dense sprays

    NASA Technical Reports Server (NTRS)

    Dodge, L. G.

    1984-01-01

    A calibration procedure for diffraction-based particle-sizing instruments using multielement detectors is briefly reviewed. The effects of multiple scattering due to dense sprays on the calibration of these instruments are then examined over a range of sprays with Sauter mean diameters from 20 to 55 microns. An empirical scheme to correct for changes in calibration due to dense sprays or other scattering media is presented.

  5. A functional technique based on the Euclidean algorithm with applications to 2-D acoustic diffractal diffusers

    NASA Astrophysics Data System (ADS)

    Cortés-Vega, Luis

    2015-09-01

    We built, based on the Euclidean algorithm, a functional technique, which allows to discover a direct proof of Chinese Remainder Theorem. Afterwards, by using this functional approach, we present some applications to 2-D acoustic diffractal diffusers. The novelty of the method is their functional algorithmic character, which improves ideas, as well as, other results of the author and his collaborators in a previous work.

  6. Modelling of diffraction grating based optical filters for fluorescence detection of biomolecules

    PubMed Central

    Kovačič, M.; Krč, J.; Lipovšek, B.; Topič, M.

    2014-01-01

    The detection of biomolecules based on fluorescence measurements is a powerful diagnostic tool for the acquisition of genetic, proteomic and cellular information. One key performance limiting factor remains the integrated optical filter, which is designed to reject strong excitation light while transmitting weak emission (fluorescent) light to the photodetector. Conventional filters have several disadvantages. For instance absorbing filters, like those made from amorphous silicon carbide, exhibit low rejection ratios, especially in the case of small Stokes’ shift fluorophores (e.g. green fluorescent protein GFP with λexc = 480 nm and λem = 510 nm), whereas interference filters comprising many layers require complex fabrication. This paper describes an alternative solution based on dielectric diffraction gratings. These filters are not only highly efficient but require a smaller number of manufacturing steps. Using FEM-based optical modelling as a design optimization tool, three filtering concepts are explored: (i) a diffraction grating fabricated on the surface of an absorbing filter, (ii) a diffraction grating embedded in a host material with a low refractive index, and (iii) a combination of an embedded grating and an absorbing filter. Both concepts involving an embedded grating show high rejection ratios (over 100,000) for the case of GFP, but also high sensitivity to manufacturing errors and variations in the incident angle of the excitation light. Despite this, simulations show that a 60 times improvement in the rejection ratio relative to a conventional flat absorbing filter can be obtained using an optimized embedded diffraction grating fabricated on top of an absorbing filter. PMID:25071964

  7. Cyclic olefin homopolymer-based microfluidics for protein crystallization and in situ X-ray diffraction

    SciTech Connect

    Emamzadah, Soheila; Petty, Tom J.; De Almeida, Victor; Nishimura, Taisuke; Joly, Jacques; Ferrer, Jean-Luc; Halazonetis, Thanos D.

    2009-09-01

    A cyclic olefin homopolymer-based microfluidics system has been established for protein crystallization and in situ X-ray diffraction. Microfluidics is a promising technology for the rapid identification of protein crystallization conditions. However, most of the existing systems utilize silicone elastomers as the chip material which, despite its many benefits, is highly permeable to water vapour. This limits the time available for protein crystallization to less than a week. Here, the use of a cyclic olefin homopolymer-based microfluidics system for protein crystallization and in situ X-ray diffraction is described. Liquid handling in this system is performed in 2 mm thin transparent cards which contain 500 chambers, each with a volume of 320 nl. Microbatch, vapour-diffusion and free-interface diffusion protocols for protein crystallization were implemented and crystals were obtained of a number of proteins, including chicken lysozyme, bovine trypsin, a human p53 protein containing both the DNA-binding and oligomerization domains bound to DNA and a functionally important domain of Arabidopsis Morpheus’ molecule 1 (MOM1). The latter two polypeptides have not been crystallized previously. For X-ray diffraction analysis, either the cards were opened to allow mounting of the crystals on loops or the crystals were exposed to X-rays in situ. For lysozyme, an entire X-ray diffraction data set at 1.5 Å resolution was collected without removing the crystal from the card. Thus, cyclic olefin homopolymer-based microfluidics systems have the potential to further automate protein crystallization and structural genomics efforts.

  8. A fast multispectral light synthesiser based on LEDs and a diffraction grating.

    PubMed

    Belušič, Gregor; Ilić, Marko; Meglič, Andrej; Pirih, Primož

    2016-01-01

    Optical experiments often require fast-switching light sources with adjustable bandwidths and intensities. We constructed a wavelength combiner based on a reflective planar diffraction grating and light emitting diodes with emission peaks from 350 to 630 nm that were positioned at the angles corresponding to the first diffraction order of the reversed beam. The combined output beam was launched into a fibre. The spacing between 22 equally wide spectral bands was about 15 nm. The time resolution of the pulse-width modulation drivers was 1 ms. The source was validated with a fast intracellular measurement of the spectral sensitivity of blowfly photoreceptors. In hyperspectral imaging of Xenopus skin circulation, the wavelength resolution was adequate to resolve haemoglobin absorption spectra. The device contains no moving parts, has low stray light and is intrinsically capable of multi-band output. Possible applications include visual physiology, biomedical optics, microscopy and spectroscopy. PMID:27558155

  9. A fast multispectral light synthesiser based on LEDs and a diffraction grating

    NASA Astrophysics Data System (ADS)

    Belušič, Gregor; Ilić, Marko; Meglič, Andrej; Pirih, Primož

    2016-08-01

    Optical experiments often require fast-switching light sources with adjustable bandwidths and intensities. We constructed a wavelength combiner based on a reflective planar diffraction grating and light emitting diodes with emission peaks from 350 to 630 nm that were positioned at the angles corresponding to the first diffraction order of the reversed beam. The combined output beam was launched into a fibre. The spacing between 22 equally wide spectral bands was about 15 nm. The time resolution of the pulse-width modulation drivers was 1 ms. The source was validated with a fast intracellular measurement of the spectral sensitivity of blowfly photoreceptors. In hyperspectral imaging of Xenopus skin circulation, the wavelength resolution was adequate to resolve haemoglobin absorption spectra. The device contains no moving parts, has low stray light and is intrinsically capable of multi-band output. Possible applications include visual physiology, biomedical optics, microscopy and spectroscopy.

  10. A fast multispectral light synthesiser based on LEDs and a diffraction grating

    PubMed Central

    Belušič, Gregor; Ilić, Marko; Meglič, Andrej; Pirih, Primož

    2016-01-01

    Optical experiments often require fast-switching light sources with adjustable bandwidths and intensities. We constructed a wavelength combiner based on a reflective planar diffraction grating and light emitting diodes with emission peaks from 350 to 630 nm that were positioned at the angles corresponding to the first diffraction order of the reversed beam. The combined output beam was launched into a fibre. The spacing between 22 equally wide spectral bands was about 15 nm. The time resolution of the pulse-width modulation drivers was 1 ms. The source was validated with a fast intracellular measurement of the spectral sensitivity of blowfly photoreceptors. In hyperspectral imaging of Xenopus skin circulation, the wavelength resolution was adequate to resolve haemoglobin absorption spectra. The device contains no moving parts, has low stray light and is intrinsically capable of multi-band output. Possible applications include visual physiology, biomedical optics, microscopy and spectroscopy. PMID:27558155

  11. Beating the Rayleigh limit: orbital-angular-momentum-based super-resolution diffraction tomography.

    PubMed

    Li, Lianlin; Li, Fang

    2013-09-01

    This paper reports a super-resolution imaging approach based on orbital-angular-momentum diffraction tomography (OAM-DT), which makes an important breakthrough on the Rayleigh limit associated with conventional diffraction tomography (DT) technique. It is well accepted that orbital-angular momentum (OAM) provides additional electromagnetic degrees of freedom. This concept has been widely applied in science and technology. In this paper we revisit the DT problem extended with OAM, and demonstrate theoretically and numerically that there is no physical limit on imaging resolution with OAM-DT. The physical mechanism behind it is that either the near field or superoscillation of the transmitter is employed to super-resolve probed objects. This super-resolution OAM-DT imaging paradigm does not require near-field measurement, a subtle focusing lens, or complicated postprocessing, etc., thus providing an approach to realize the wave-field imaging of universal objects with subwavelength resolution.

  12. Switchable diffraction gratings based on inversion of the dielectric anisotropy in nematic liquid crystals

    SciTech Connect

    Kang, S. W.; Sprunt, S.; Chien, L. C.

    2001-06-11

    A switchable liquid crystal diffraction grating, responsive to both the frequency and magnitude of an applied voltage, is demonstrated. The grating is based on polymer stabilization of modulated states of the liquid crystal optic axis induced at frequencies near a sign inversion of the dielectric anisotropy. In a particular case of frequency-based switching, 70% of the transmitted intensity of a 633 nm laser beam can be shifted into or out of a {+-}12{degree} forward arc by changing the frequency of an applied voltage between 10 and 16 kHz at a fixed amplitude of 27 V. {copyright} 2001 American Institute of Physics.

  13. Enumerating Pathways of Proton Abstraction Based on a Spatial and Electrostatic Analysis of Residues in the Catalytic Site

    PubMed Central

    Chakraborty, Sandeep

    2012-01-01

    The pathways of proton abstraction (PA), a key aspect of most catalytic reactions, is often controversial and highly debated. Ultrahigh-resolution diffraction studies, molecular dynamics, quantum mechanics and molecular mechanic simulations are often adopted to gain insights in the PA mechanisms in enzymes. These methods require expertise and effort to setup and can be computationally intensive. We present a push button methodology – Proton abstraction Simulation (PRISM) – to enumerate the possible pathways of PA in a protein with known 3D structure based on the spatial and electrostatic properties of residues in the proximity of a given nucleophilic residue. Proton movements are evaluated in the vicinity of this nucleophilic residue based on distances, potential differences, spatial channels and characteristics of the individual residues (polarity, acidic, basic, etc). Modulating these parameters eliminates their empirical nature and also might reveal pathways that originate from conformational changes. We have validated our method using serine proteases and concurred with the dichotomy in PA in Class A β-lactamases, both of which are hydrolases. The PA mechanism in a transferase has also been corroborated. The source code is made available at www.sanchak.com/prism. PMID:22745790

  14. Focal length measurement based on Fresnel diffraction from a phase plate.

    PubMed

    Dashtdar, Masoomeh; Mohammad-Ali Hosseini-Saber, S

    2016-09-10

    A method based on the Fresnel diffraction of light from the phase step is introduced for measuring effective focal length (EFL) and back focal length (BFL) of optical imaging systems. It is shown that, as a transparent plane-parallel plate is illuminated at a boundary region by a monochromatic beam of light, Fresnel diffraction occurs because of the abrupt change in phase imposed by the finite change in refractive index at the plate boundary. Variation of the incident angle in a convergent (or divergent) beam of light causes the periodic intensity along the central fringe of the diffraction pattern. The measurement of the extrema position of the intensity distribution accurately provides the EFL and BFL. The technique is easy to apply and can measure a wide range of both positive and negative focal lengths. The measuring setup can be very compact with low mechanical and optical noises. As examples of this technique, the EFLs of five different lenses are experimentally obtained. The results are quite consistent with the values indicated by the lens manufacturer.

  15. Use of synchrotron based diffraction enhanced imaging for visualization of soft tissues in invertebrates

    SciTech Connect

    Rao, D.; Zhong, Z.; Swapna, M.; Cesareo, R.; Brunetti, A.; Akatsuka, T.; Yuasa, T.; Takeda, T.; Gigante, G.

    2010-04-04

    Images of terrestrial and marine invertebrates (snails and bivalves) have been obtained by using an X-ray phase-contrast imaging technique, namely, synchrotron-based diffraction-enhanced imaging. Synchrotron X-rays of 20, 30 and 40 keV were used, which penetrate deep enough into animal soft tissues. The phase of X-ray photons shifts slightly as they traverse an object, such as animal soft tissue, and interact with its atoms. Biological features, such as shell morphology and animal physiology, have been visualized. The contrast of the images obtained at 40 keV is the best. This optimum energy provided a clear view of the internal structural organization of the soft tissue with better contrast. The contrast is higher at edges of internal soft-tissue structures. The image improvements achieved with the diffraction-enhanced imaging technique are due to extinction, i.e., elimination of ultra-small-angle scattering. They enabled us to identify a few embedded internal shell features, such as the origin of the apex, which is the firmly attached region of the soft tissue connecting the umbilicus to the external morphology. Diffraction-enhanced imaging can provide high-quality images of soft tissues valuable for biology.

  16. New long trace profiler based on phase plate diffraction for optical metrology of SSRF

    NASA Astrophysics Data System (ADS)

    Zeng, Danhua; Xiao, Tiqiao; Du, Guohao; Wen, Li; Luo, Hongxin; Xia, Shaojian; Xu, Hongjie

    2006-09-01

    A long trace profiler LTP-1200, with a novel f-θ system based on phase plate diffraction and a scanning range up to 1200mm, has been developed at Shanghai Synchrotron Radiation Facility. The central dark line in the diffraction pattern generated by a π phase plate is taken as the positioning benchmark. A magnet levitated linear rail with very high accuracy is used. A granite bench is employed to reduce deformation due to self-gravity of the rail. The focused diffraction pattern is recorded with an area charge-coupled device. The generalized regression neural network algorithm is adopted to improve the beam positioning precision. The static stability of LTP-1200 in 5h is 0.14μrad, and the repeatability reaches 0.05μrad in a common laboratory without any special control of temperature, air turbulence, etc. Calibration tests were carried out with a high precision autocollimator and a standard spherical mirror, respectively. Results show the high performance and reliability of the LTP-1200.

  17. Focal length measurement based on Fresnel diffraction from a phase plate.

    PubMed

    Dashtdar, Masoomeh; Mohammad-Ali Hosseini-Saber, S

    2016-09-10

    A method based on the Fresnel diffraction of light from the phase step is introduced for measuring effective focal length (EFL) and back focal length (BFL) of optical imaging systems. It is shown that, as a transparent plane-parallel plate is illuminated at a boundary region by a monochromatic beam of light, Fresnel diffraction occurs because of the abrupt change in phase imposed by the finite change in refractive index at the plate boundary. Variation of the incident angle in a convergent (or divergent) beam of light causes the periodic intensity along the central fringe of the diffraction pattern. The measurement of the extrema position of the intensity distribution accurately provides the EFL and BFL. The technique is easy to apply and can measure a wide range of both positive and negative focal lengths. The measuring setup can be very compact with low mechanical and optical noises. As examples of this technique, the EFLs of five different lenses are experimentally obtained. The results are quite consistent with the values indicated by the lens manufacturer. PMID:27661386

  18. New long trace profiler based on phase plate diffraction for optical metrology of SSRF

    SciTech Connect

    Zeng Danhua; Xiao Tiqiao; Du Guohao; Wen Li; Luo Hongxin; Xia Shaojian; Xu Hongjie

    2006-09-15

    A long trace profiler LTP-1200, with a novel f-{theta} system based on phase plate diffraction and a scanning range up to 1200 mm, has been developed at Shanghai Synchrotron Radiation Facility. The central dark line in the diffraction pattern generated by a {pi} phase plate is taken as the positioning benchmark. A magnet levitated linear rail with very high accuracy is used. A granite bench is employed to reduce deformation due to self-gravity of the rail. The focused diffraction pattern is recorded with an area charge-coupled device. The generalized regression neural network algorithm is adopted to improve the beam positioning precision. The static stability of LTP-1200 in 5 h is 0.14 {mu}rad, and the repeatability reaches 0.05 {mu}rad in a common laboratory without any special control of temperature, air turbulence, etc. Calibration tests were carried out with a high precision autocollimator and a standard spherical mirror, respectively. Results show the high performance and reliability of the LTP-1200.

  19. Demodulation technique based on diffraction optical elements for fiber Bragg grating sensing system

    NASA Astrophysics Data System (ADS)

    Feng, Zhongwei; Zhang, Li

    2010-11-01

    A new demodulation technique based on diffraction grating is proposed for high speed application. Compared with tunable filter method, the diffraction grating method has the advantages of potential high interrogation speed, high energy efficiency, no sweeping movements, which makes it a competitive interrogation method in certain field such as dynamic strain monitoring. The optical layout is crucial to guarantee the required performance of the interrogator. A structure which consists of two diffraction gratings, a fiber collimator, a reflection mirror, and a detector is adopted in the consideration of spectrum resolution, optical aberration, and geometrical size. The initial parameters for the structure are figured out by the optical path calculation involving the coefficient of the employed optical elements. The optimized procedure is following sequentially in order to minimize the aberration and obtain the pre-defined specifications theoretically. As the central wavelength for the interrogator is 1550nm, the InGaAs linear array sensor is introduced as the photoelectrical detector. Experiment of demodulation for FBG sensing system is carried out to verify the feasibility of this technique. The wavelength resolution for the interrogator is 1pm, and the demodulation speed is about 2kHz.

  20. Determination of pesticide residues in fruit-based soft drinks.

    PubMed

    García-Reyes, Juan F; Gilbert-López, Bienvenida; Molina-Díaz, Antonio; Fernández-Alba, Amadeo R

    2008-12-01

    Here we report the first worldwide reconnaissance study of the presence and occurrence of pesticides in fruit-based soft drinks. While there are strict regulations and exhaustive controls for pesticides in fruits, vegetables, and drinking water, scarce attention has been paid to highly consumed derivate products, which may contain these commodities as ingredients. In the case of the fruit-based soft drinks industry, there are no clear regulations, relating to pesticides, which address them, even when there is significant consumption in vulnerable groups such as children. In this work, we have developed a screening method to search automatically for up to 100 pesticides in fruit-based soft drinks extracts based on the application of liquid chromatography-electrospray time-of-flight mass spectrometry (LC-TOF MS). The sample extracts injected were obtained by a preliminary sample treatment step based on solid-phase extraction using hydrophilic-lipophilic balanced polymer-based reverse phase cartridges and methanol as eluting solvent. Subsequent identification, confirmation, and quantitation were carried out by LC-TOF MS analysis: the confirmation of the target species was based on retention time matching and accurate mass measurements of protonated molecules ([M + H]+) and fragment ions (obtaining accuracy errors typically lower than 2 ppm). With the proposed method, we measured over 100 fruit-based soft drink samples, purchased from 15 different countries from companies with brands distributed worldwide and found relatively large concentration levels of pesticides in most of the samples analyzed. The concentration levels detected were of the micrograms per liter level, low when considering the European maximum residue levels (MRLs) set for fruits but very high (i.e., 300 times) when considering the MRLs for drinking or bottled water. The detected pesticides (carbendazim, thiabendazole, imazalil and its main degradate, prochloraz and its main degradate, malathion, and

  1. Intensity-based image registration by minimizing residual complexity.

    PubMed

    Myronenko, Andriy; Song, Xubo

    2010-11-01

    Accurate definition of the similarity measure is a key component in image registration. Most commonly used intensity-based similarity measures rely on the assumptions of independence and stationarity of the intensities from pixel to pixel. Such measures cannot capture the complex interactions among the pixel intensities, and often result in less satisfactory registration performances, especially in the presence of spatially-varying intensity distortions. We propose a novel similarity measure that accounts for intensity nonstationarities and complex spatially-varying intensity distortions in mono-modal settings. We derive the similarity measure by analytically solving for the intensity correction field and its adaptive regularization. The final measure can be interpreted as one that favors a registration with minimum compression complexity of the residual image between the two registered images. One of the key advantages of the new similarity measure is its simplicity in terms of both computational complexity and implementation. This measure produces accurate registration results on both artificial and real-world problems that we have tested, and outperforms other state-of-the-art similarity measures in these cases.

  2. Performance enhancement of thin film silicon solar cells based on distributed Bragg reflector and diffraction grating

    SciTech Connect

    Dubey, R. S.; Saravanan, S.; Kalainathan, S.

    2014-12-15

    The influence of various designing parameters were investigated and explored for high performance solar cells. Single layer grating based solar cell of 50 μm thickness gives maximum efficiency up to 24 % whereas same efficiency is achieved with the use of three bilayers grating based solar cell of 30 μm thickness. Remarkably, bilayer grating based solar cell design not only gives broadband absorption but also enhancement in efficiency with reduced cell thickness requirement. This absorption enhancement is attributed to the high reflection and diffraction from DBR and grating respectively. The obtained short-circuit current were 29.6, 32.9, 34.6 and 36.05 mA/cm{sup 2} of 5, 10, 20 and 30 μm cell thicknesses respectively. These presented designing efforts would be helpful to design and realize new generation of solar cells.

  3. Evolution in boron-based GEM detectors for diffraction measurements: from planar to 3D converters

    NASA Astrophysics Data System (ADS)

    Albani, Giorgia; Perelli Cippo, Enrico; Croci, Gabriele; Muraro, Andrea; Schooneveld, Erik; Scherillo, Antonella; Hall-Wilton, Richard; Kanaki, Kalliopi; Höglund, Carina; Hultman, Lars; Birch, Jens; Claps, Gerardo; Murtas, Fabrizio; Rebai, Marica; Tardocchi, Marco; Gorini, Giuseppe

    2016-11-01

    The so-called ‘3He-crisis’ has motivated the neutron detector community to undertake an intense R&D programme in order to develop technologies alternative to standard 3He tubes and suitable for neutron detection systems in future spallation sources such as the European spallation source (ESS). Boron-based GEM (gas electron multiplier) detectors are a promising ‘3He-free’ technology for thermal neutron detection in neutron scattering experiments. In this paper the evolution of boron-based GEM detectors from planar to 3D converters with an application in diffraction measurements is presented. The use of 3D converters coupled with GEMs allows for an optimization of the detector performances. Three different detectors were used for diffraction measurements on the INES instrument at the ISIS spallation source. The performances of the GEM-detectors are compared with those of conventional 3He tubes installed on the INES instrument. The conceptual detector with the 3D converter used in this paper reached a count rate per unit area of about 25% relative to the currently installed 3He tube. Its timing resolution is similar and the signal-to-background ratio (S/B) is 2 times lower.

  4. Optical cryptosystem based on phase-truncated Fresnel diffraction and transport of intensity equation.

    PubMed

    Zhang, Chenggong; He, Wenqi; Wu, Jiachen; Peng, Xiang

    2015-04-01

    A novel optical cryptosystem based on phase-truncated Fresnel diffraction (PTFD) and transport of intensity equation (TIE) is proposed. By using the phase truncation technique, a phase-encoded plaintext could be encrypted into a real-valued noise-like intensity distribution by employing a random amplitude mask (RAM) and a random phase mask (RPM), which are regarded as two secret keys. For decryption, a generalized amplitude-phase retrieval (GAPR) algorithm combined with the TIE method are proposed to recover the plaintext with the help of two keys. Different from the current phase-truncated-based optical cryptosystems which need record the truncated phase as decryption keys, our scheme do not need the truncated phase because of the introducing of the TIE method. Moreover, the proposed scheme is expected to against existing attacks. A set of numerical simulation results show the feasibility and security of the proposed method. PMID:25968722

  5. Novel copyright information hiding method based on random phase matrix of Fresnel diffraction transforms

    NASA Astrophysics Data System (ADS)

    Cao, Chao; Chen, Ru-jun

    2009-10-01

    In this paper, we present a new copyright information hide method for digital images in Moiré fringe formats. The copyright information is embedded into the protected image and the detecting image based on Fresnel phase matrix. Firstly, using Fresnel diffraction transform, the random phase matrix of copyright information is generated. Then, according to Moiré fringe principle, the protected image and the detecting image are modulated respectively based on the random phase matrix, and the copyright information is embedded into them. When the protected image and the detecting image are overlapped, the copyright information can reappear. Experiment results show that our method has good concealment performance, and is a new way for copyright protection.

  6. X-ray diffraction of slag-based sodium salt waste forms

    SciTech Connect

    Langton, C. A.; Missimer, D. M.

    2014-09-30

    The attached report documents sample preparation and x-ray diffraction results for a series of cement and blended cement matrices prepared with either water or a 4.4 M Na salt solution. The objective of the study was to provide initial phase characterization for the Cementitious Barriers Partnership reference case cementitious salt waste form. This information can be used to: 1) generate a base line for the evolution of the waste form as a function of time and conditions, 2) potentially to design new binders based on mineralogy of the binder, 3) understand and predict anion and cation leaching behavior of contaminants of concern, and 4) predict performance of the waste forms for which phase solubility and thermodynamic data are available.

  7. 100-watt fiber-based green laser with near diffraction-limited beam quality

    NASA Astrophysics Data System (ADS)

    Hu, Dan; Eisenberg, Eric; Brar, Khush; Yilmaz, Tolga; Honea, Eric

    2010-02-01

    An air-cooled, light-weight, fiber-based, high power green laser has been prototyped. The system consists of an all-fibercoupled IR pump laser at 1064 nm and a frequency-conversion module in a compact and flexible configuration. The IR laser operates in QCW mode, with 10 MHz pulse repetition frequency and 3-5 ns pulse width, to generate sufficient peak power for frequency doubling in the converter module. The IR laser can produce more than 200 W in a linearlypolarized diffraction-limited output beam with high spectral brightness for frequency conversion. The converter module has an input telescope and an oven with a nonlinear crystal to efficiently convert the 1064-nm IR fiber laser output to 532-nm green output. The IR laser and conversion module are connected via a stainless-steel protected delivery fiber for optical beam delivery and an electrical cable harness for electrical power delivery and system control. The beam quality of the 532 nm output remains near diffraction-limited, with M2<1.4. Up to 101 W of 532 nm output was demonstrated and multi-hour runs were characterized at 75 W output. The weights of the IR laser package and doubler are 69 lbs and 14 lbs respectively. An overview of the system and full characterization results will be presented. Such compact, highbrightness green laser sources are expected to enable various scientific, defense and industrial applications.

  8. Calibration diagnostic and updating strategy based on quantitative modeling of near-infrared spectral residuals.

    PubMed

    Yu, Hua; Small, Gary W

    2015-02-01

    A diagnostic and updating strategy is explored for multivariate calibrations based on near-infrared spectroscopy. For use with calibration models derived from spectral fitting or decomposition techniques, the proposed method constructs models that relate the residual concentrations remaining after a prediction to the residual spectra remaining after the information associated with the calibration model has been extracted. This residual modeling approach is evaluated for use with partial least-squares (PLS) models for predicting physiological levels of glucose in a simulated biological matrix. Residual models are constructed with both PLS and a hybrid technique based on the use of PLS scores as inputs to support vector regression. Calibration and residual models are built with both absorbance and single-beam data collected over 416 days. Effective models for the spectral residuals are built with both types of data and demonstrate the ability to diagnose and correct deviations in performance of the calibration model with time. PMID:25473807

  9. Quantification of Pharmaceutical Compounds Based on Powder X-Ray Diffraction with Chemometrics.

    PubMed

    Otsuka, Yuta; Ito, Akira; Matsumura, Saki; Takeuchi, Masaki; Pal, Suvra; Tanaka, Hideji

    2016-01-01

    We propose an approach for the simultaneous determination of multiple components in pharmaceutical mixed powder based on powder X-ray diffraction (PXRD) method coupled with chemometrics. Caffeine anhydrate, acetaminophen and lactose monohydrate were mixed at various ratios. The samples were analyzed by PXRD method in the ranges of 2θ=5.00-30.0 and 35.0-45.0 degrees. Obtained diffractograms were analyzed by conventional peak intensity method, multi curve resolution (MCR)-alternating least squares (ALS) method and partial least squares (PLS) method. Constructed PLS models can most accurately predict the concentrations among different methods used. Each regression vector of PLS correlates not only to the compound of interest but also to the coexisting compounds. The combination of PXRD and PLS methods is concluded to be powerful approach for analyzing multi components in pharmaceutical formulations. PMID:27477651

  10. Thin film solar cell design based on photonic crystal and diffractive grating structures.

    PubMed

    Mutitu, James G; Shi, Shouyuan; Chen, Caihua; Creazzo, Timothy; Barnett, Allen; Honsberg, Christiana; Prather, Dennis W

    2008-09-15

    In this paper we present novel light trapping designs applied to multiple junction thin film solar cells. The new designs incorporate one dimensional photonic crystals as band pass filters that reflect short light wavelengths (400 - 867 nm) and transmit longer wavelengths(867 -1800 nm) at the interface between two adjacent cells. In addition, nano structured diffractive gratings that cut into the photonic crystal layers are incorporated to redirect incoming waves and hence increase the optical path length of light within the solar cells. Two designs based on the nano structured gratings that have been realized using the scattering matrix and particle swarm optimization methods are presented. We also show preliminary fabrication results of the proposed devices.

  11. High efficiency near diffraction-limited mid-infrared flat lenses based on metasurface reflectarrays.

    PubMed

    Zhang, Shuyan; Kim, Myoung-Hwan; Aieta, Francesco; She, Alan; Mansuripur, Tobias; Gabay, Ilan; Khorasaninejad, Mohammadreza; Rousso, David; Wang, Xiaojun; Troccoli, Mariano; Yu, Nanfang; Capasso, Federico

    2016-08-01

    We report the first demonstration of a mid-IR reflection-based flat lens with high efficiency and near diffraction-limited focusing. Focusing efficiency as high as 80%, in good agreement with simulations (83%), has been achieved at 45° incidence angle at λ = 4.6 μm. The off-axis geometry considerably simplifies the optical arrangement compared to the common geometry of normal incidence in reflection mode which requires beam splitters. Simulations show that the effects of incidence angle are small compared to parabolic mirrors with the same NA. The use of single-step photolithography allows large scale fabrication. Such a device is important in the development of compact telescopes, microscopes, and spectroscopic designs. PMID:27505769

  12. A projection-based approach to diffraction tomography on curved boundaries

    NASA Astrophysics Data System (ADS)

    Clement, Gregory T.

    2014-12-01

    An approach to diffraction tomography is investigated for two-dimensional image reconstruction of objects surrounded by an arbitrarily-shaped curve of sources and receivers. Based on the integral theorem of Helmholtz and Kirchhoff, the approach relies upon a valid choice of the Green’s functions for selected conditions along the (possibly-irregular) boundary. This allows field projections from the receivers to an arbitrary external location. When performed over all source locations, it will be shown that the field caused by a hypothetical source at this external location is also known along the boundary. This field can then be projected to new external points that may serve as a virtual receiver. Under such a reformation, data may be put in a form suitable for image construction by synthetic aperture methods. Foundations of the approach are shown, followed by a mapping technique optimized for the approach. Examples formed from synthetic data are provided.

  13. Two-degree-of-freedom displacement measurement system based on double diffraction gratings

    NASA Astrophysics Data System (ADS)

    Lu, Zhengang; Wei, Peipei; Wang, Chaoqun; Jing, Jialei; Tan, Jiubin; Zhao, Xiping

    2016-07-01

    A two-degree-of-freedom (2-DOF) displacement measurement system based on double diffraction gratings is proposed in this paper, which consists of a reflective-type scale grating and a grating read head with a scanning transmission grating. Combining the traditional three-grating interference principle with the Michelson interference principle, the system can measure the displacements of a precision stage along the horizontal direction (X-axis, in the scanning grating plane and vertical to the scanning grating lines) and vertical direction (Z-axis, vertical to the scanning grating plane) simultaneously. The system has the merits of compact structure and uncoupled interference signals in the two axes. By simulating the output signals of the system and comparing them with the experimental results, the validity and feasibility of the system have been verified. The 2-DOF system will be favorable in the displacement measurement of multi-dimensional stages and multi-DOF machines.

  14. Temporal contrast improvement based on the self-diffraction process with a cylinder mirror

    NASA Astrophysics Data System (ADS)

    Li, Fangjia; Shen, Xiong; Wang, Peng; Li, Yanyan; Liu, Jun; Wang, Zhanshan; Li, Ruxin

    2016-05-01

    A cylinder reflective mirror was used to increase incident pulse energy to multi-millijoules in the research of temporal contrast enhancement based on a self-diffraction (SD) process. A 170 μJ first-order SD pulse with temporal contrast improved by 4 orders of magnitude was obtained when incident pulse energy was 5.1 mJ. In order to improve energy-conversion efficiency, a 67/33 beam splitter was used to replace the original 50/50 one. A 265 μJ first-order SD signal was achieved without damage of the glass plate at 3.7 mJ input pulse energy with an energy-conversion efficiency of about 7.1%. The generated SD pulse is expected to be used as the seed of high-contrast and high-power laser systems.

  15. A study of swing-curve physics in diffraction-based overlay

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Kaustuve; den Boef, Arie; Storms, Greet; van Heijst, Joost; Noot, Marc; An, Kevin; Park, Noh-Kyoung; Jeon, Se-Ra; Oh, Nang-Lyeom; McNamara, Elliott; van de Mast, Frank; Oh, SeungHwa; Lee, Seung Yoon; Hwang, Chan; Lee, Kuntack

    2016-03-01

    With the increase of process complexity in advanced nodes, the requirements of process robustness in overlay metrology continues to tighten. Especially with the introduction of newer materials in the film-stack along with typical stack variations (thickness, optical properties, profile asymmetry etc.), the signal formation physics in diffraction-based overlay (DBO) becomes an important aspect to apply in overlay metrology target and recipe selection. In order to address the signal formation physics, an effort is made towards studying the swing-curve phenomena through wavelength and polarizations on production stacks using simulations as well as experimental technique using DBO. The results provide a wealth of information on target and recipe selection for robustness. Details from simulation and measurements will be reported in this technical publication.

  16. High efficiency near diffraction-limited mid-infrared flat lenses based on metasurface reflectarrays

    NASA Astrophysics Data System (ADS)

    Zhang, Shuyan; Kim, Myoung-Hwan; Aieta, Francesco; She, Alan; Mansuripur, Tobias; Gabay, Ilan; Khorasaninejad, Mohammadreza; Rousso, David; Wang, Xiaojun; Troccoli, Mariano; Yu, Nanfang; Capasso, Federico

    2016-08-01

    A limiting factor in the development of mid-infrared optics is the lack of abundant materials that are transparent, low cost, lightweight, and easy to machine. In this paper, we demonstrate a metasurface device that circumvents these limitations. A flat lens based on antenna reflectarrays was designed to achieve near diffraction-limited focusing with a high efficiency (experiment: 80%, simulation: 83%) at 45(o) incidence angle at {\\lambda} = 4.6 {\\mu}m. This geometry considerably simplifies the experimental arrangement compared to the common geometry of normal incidence which requires beam splitters. Simulations show that the effect of comatic aberrations is small compared to parabolic mirrors. The use of single-step photolithography allows large scale fabrication.

  17. Digital focusing of OCT images based on scalar diffraction theory and information entropy.

    PubMed

    Liu, Guozhong; Zhi, Zhongwei; Wang, Ruikang K

    2012-11-01

    This paper describes a digital method that is capable of automatically focusing optical coherence tomography (OCT) en face images without prior knowledge of the point spread function of the imaging system. The method utilizes a scalar diffraction model to simulate wave propagation from out-of-focus scatter to the focal plane, from which the propagation distance between the out-of-focus plane and the focal plane is determined automatically via an image-definition-evaluation criterion based on information entropy theory. By use of the proposed approach, we demonstrate that the lateral resolution close to that at the focal plane can be recovered from the imaging planes outside the depth of field region with minimal loss of resolution. Fresh onion tissues and mouse fat tissues are used in the experiments to show the performance of the proposed method.

  18. Diffraction-Based Techniques For High Contrast X-ray Imaging

    NASA Astrophysics Data System (ADS)

    Peerzada, Lubna Naseem

    Two X-ray diffraction based techniques for high contrast were explored to improve contrast in radiology: diffraction enhanced imaging (DEI) and coherent scatter imaging. DEI produces contrast in images based upon the difference in the X-ray refractive indices of materials or tissues. Two DEI systems were devised. Both were comprised of a conventional polychromatic copper X-ray source, polycapillary collimating optics and two silicon crystals.Lucite step phantoms and nylon tubing were imaged. No fringe effects were observed. The lack of observable edge enhancement may have been due to the optic structure which obscured refraction effects. Better results might have been achieved if a higher resolution detector or phantom of larger step size or larger diameter thin walled tubing had been used. The second technique was coherent scatter X-ray imaging. The purpose of this work was to differentiate between healthy and diseased human breast tissues. For instance, breast carcinoma is known to have a peak coherent scattering angle at 12.2° for Mo Ka radiation at 17.5 keV, whereas fatty tissue peaks around 9°. A system which would be compatible with screening mammography was developed. The system was expanded to include sample scanning to allow for a larger image area. The modulation transfer function was computed for static and scanned images of a resolution phantom. These showed good agreement, indicating that the scanning was properly aligned and timed. Static and scanned images of phantoms were taken and the contrast was calculated for a series of experimental parameters including, grid tilt angle. A complex phantom was also then imaged. It was possible to distinguish tissue-equivalent phantom types. Good contrast resolution scanned images were obtained which is promising for a diagnostic system.

  19. Numerical manifold method based on the method of weighted residuals

    NASA Astrophysics Data System (ADS)

    Li, S.; Cheng, Y.; Wu, Y.-F.

    2005-05-01

    Usually, the governing equations of the numerical manifold method (NMM) are derived from the minimum potential energy principle. For many applied problems it is difficult to derive in general outset the functional forms of the governing equations. This obviously strongly restricts the implementation of the minimum potential energy principle or other variational principles in NMM. In fact, the governing equations of NMM can be derived from a more general method of weighted residuals. By choosing suitable weight functions, the derivation of the governing equations of the NMM from the weighted residual method leads to the same result as that derived from the minimum potential energy principle. This is demonstrated in the paper by deriving the governing equations of the NMM for linear elasticity problems, and also for Laplace's equation for which the governing equations of the NMM cannot be derived from the minimum potential energy principle. The performance of the method is illustrated by three numerical examples.

  20. Focal construct geometry for high intensity energy dispersive x-ray diffraction based on x-ray capillary optics.

    PubMed

    Li, Fangzuo; Liu, Zhiguo; Sun, Tianxi; Jiang, Bowen; Zhu, Yu

    2016-03-14

    We presented a focal construct geometry (FCG) method for high intensity energy dispersive X-ray diffraction by utilizing a home-made ellipsoidal single-bounce capillary (ESBC) and a polycapillary parallel X-ray lens (PPXRL). The ESBC was employed to focus the X-rays from a conventional laboratory source into a small focal spot and to produce an annular X-ray beam in the far-field. Additionally, diffracted polychromatic X-rays were confocally collected by the PPXRL attached to a stationary energy-resolved detector. Our FCG method based on ESBC and PPXRL had achieved relatively high intensity diffraction peaks and effectively narrowed the diffraction peak width which was helpful in improving the potential d-spacing resolution for material phase analysis.

  1. Relation between the Rayleigh equation in diffraction theory and the equation based on Green's formula

    NASA Astrophysics Data System (ADS)

    Tatarskii, V. I.

    1995-06-01

    The steps necessary to produce the Rayleigh equation that is based on the Rayleigh hypothesis from the equation that is based on the Green's formula are shown. First a definition is given for the scattering amplitude that is true not only in the far zone of diffraction but also near the scattering surface. With this definition the Rayleigh equation coincides with the rigorous equation for the surface secondary sources that is based on Green's formula. The Rayleigh hypothesis is equivalent to substituting the far-zone expression of the scattering amplitude into this rigorous equation. In this case it turns out to be the equation not for the sources but directly for the scattering amplitude, which is the main advantage of this method. For comparing the Rayleigh equation with the initial rigorous equation, the Rayleigh equation is represented in terms of secondary sources. The kernel of this equation contains an integral that converges for positive and diverges for negative values of some parameter. It is shown that if we regularize this integral, defining it for the negative values of this parameter as an analytical continuation from the domain of positive values, this kernel becomes equal to the kernel of the initial rigorous equation. It follows that the formal perturbation series for the scattering amplitude obtained from the Rayleigh equation and from Green's equation always coincide. This means that convergence of the perturbation series is a sufficient condition

  2. Sparsity-based super-resolved coherent diffraction imaging of one-dimensional objects

    PubMed Central

    Sidorenko, Pavel; Kfir, Ofer; Shechtman, Yoav; Fleischer, Avner; Eldar, Yonina C.; Segev, Mordechai; Cohen, Oren

    2015-01-01

    Phase-retrieval problems of one-dimensional (1D) signals are known to suffer from ambiguity that hampers their recovery from measurements of their Fourier magnitude, even when their support (a region that confines the signal) is known. Here we demonstrate sparsity-based coherent diffraction imaging of 1D objects using extreme-ultraviolet radiation produced from high harmonic generation. Using sparsity as prior information removes the ambiguity in many cases and enhances the resolution beyond the physical limit of the microscope. Our approach may be used in a variety of problems, such as diagnostics of defects in microelectronic chips. Importantly, this is the first demonstration of sparsity-based 1D phase retrieval from actual experiments, hence it paves the way for greatly improving the performance of Fourier-based measurement systems where 1D signals are inherent, such as diagnostics of ultrashort laser pulses, deciphering the complex time-dependent response functions (for example, time-dependent permittivity and permeability) from spectral measurements and vice versa. PMID:26345495

  3. Sub-Diffraction Limited Writing based on Laser Induced Periodic Surface Structures (LIPSS)

    PubMed Central

    He, Xiaolong; Datta, Anurup; Nam, Woongsik; Traverso, Luis M.; Xu, Xianfan

    2016-01-01

    Controlled fabrication of single and multiple nanostructures far below the diffraction limit using a method based on laser induced periodic surface structure (LIPSS) is presented. In typical LIPSS, multiple lines with a certain spatial periodicity, but often not well-aligned, were produced. In this work, well-controlled and aligned nanowires and nanogrooves with widths as small as 40 nm and 60 nm with desired orientation and length are fabricated. Moreover, single nanowire and nanogroove were fabricated based on the same mechanism for forming multiple, periodic structures. Combining numerical modeling and AFM/SEM analyses, it was found these nanostructures were formed through the interference between the incident laser radiation and the surface plasmons, the mechanism for forming LIPSS on a dielectric surface using a high power femtosecond laser. We expect that our method, in particular, the fabrication of single nanowires and nanogrooves could be a promising alternative for fabrication of nanoscale devices due to its simplicity, flexibility, and versatility. PMID:27721428

  4. Sub-Diffraction Limited Writing based on Laser Induced Periodic Surface Structures (LIPSS)

    NASA Astrophysics Data System (ADS)

    He, Xiaolong; Datta, Anurup; Nam, Woongsik; Traverso, Luis M.; Xu, Xianfan

    2016-10-01

    Controlled fabrication of single and multiple nanostructures far below the diffraction limit using a method based on laser induced periodic surface structure (LIPSS) is presented. In typical LIPSS, multiple lines with a certain spatial periodicity, but often not well-aligned, were produced. In this work, well-controlled and aligned nanowires and nanogrooves with widths as small as 40 nm and 60 nm with desired orientation and length are fabricated. Moreover, single nanowire and nanogroove were fabricated based on the same mechanism for forming multiple, periodic structures. Combining numerical modeling and AFM/SEM analyses, it was found these nanostructures were formed through the interference between the incident laser radiation and the surface plasmons, the mechanism for forming LIPSS on a dielectric surface using a high power femtosecond laser. We expect that our method, in particular, the fabrication of single nanowires and nanogrooves could be a promising alternative for fabrication of nanoscale devices due to its simplicity, flexibility, and versatility.

  5. Tunable Diffractive Optical Elements Based on Shape-Memory Polymers Fabricated via Hot Embossing.

    PubMed

    Schauer, Senta; Meier, Tobias; Reinhard, Maximilian; Röhrig, Michael; Schneider, Marc; Heilig, Markus; Kolew, Alexander; Worgull, Matthias; Hölscher, Hendrik

    2016-04-13

    We introduce actively tunable diffractive optical elements fabricated from shape-memory polymers (SMPs). By utilizing the shape-memory effect of the polymer, at least one crucial attribute of the diffractive optical element (DOE) is tunable and adjustable subsequent to the completed fabrication process. A thermoplastic, transparent, thermoresponsive polyurethane SMP was structured with diverse diffractive microstructures via hot embossing. The tunability was enabled by programming a second, temporary shape into the diffractive optical element by mechanical deformation, either by stretching or a second embossing cycle at low temperatures. Upon exposure to the stimulus heat, the structures change continuously and controllable in a predefined way. We establish the novel concept of shape-memory diffractive optical elements by illustrating their capabilities, with regard to tunability, by displaying the morphing diffractive pattern of a height tunable and a period tunable structure, respectively. A sample where an arbitrary structure is transformed to a second, disparate one is illustrated as well. To prove the applicability of our tunable shape-memory diffractive optical elements, we verified their long-term stability and demonstrated the precise adjustability with a detailed analysis of the recovery dynamics, in terms of temperature dependence and spatially resolved, time-dependent recovery. PMID:26998646

  6. Tunable Diffractive Optical Elements Based on Shape-Memory Polymers Fabricated via Hot Embossing.

    PubMed

    Schauer, Senta; Meier, Tobias; Reinhard, Maximilian; Röhrig, Michael; Schneider, Marc; Heilig, Markus; Kolew, Alexander; Worgull, Matthias; Hölscher, Hendrik

    2016-04-13

    We introduce actively tunable diffractive optical elements fabricated from shape-memory polymers (SMPs). By utilizing the shape-memory effect of the polymer, at least one crucial attribute of the diffractive optical element (DOE) is tunable and adjustable subsequent to the completed fabrication process. A thermoplastic, transparent, thermoresponsive polyurethane SMP was structured with diverse diffractive microstructures via hot embossing. The tunability was enabled by programming a second, temporary shape into the diffractive optical element by mechanical deformation, either by stretching or a second embossing cycle at low temperatures. Upon exposure to the stimulus heat, the structures change continuously and controllable in a predefined way. We establish the novel concept of shape-memory diffractive optical elements by illustrating their capabilities, with regard to tunability, by displaying the morphing diffractive pattern of a height tunable and a period tunable structure, respectively. A sample where an arbitrary structure is transformed to a second, disparate one is illustrated as well. To prove the applicability of our tunable shape-memory diffractive optical elements, we verified their long-term stability and demonstrated the precise adjustability with a detailed analysis of the recovery dynamics, in terms of temperature dependence and spatially resolved, time-dependent recovery.

  7. Algorithm and simulation for analysis of bio-images obtained by aperture diffraction based optical MEMS.

    PubMed

    Zhou, Xiaodong; Poenar, Daniel Puiu; Liu, Kai Yu; Tse, Man Siu; Heng, Chew-Kiat; Tan, Swee Ngin; Zhang, Nan

    2008-08-01

    This paper proposes a novel method to detect transparent living cells in a transparent microfluidic chamber by optical diffraction of an aperture or an aperture array. Through the analysis of the far-field diffraction pattern, one of the parameters of the cells, including the size, refractive index, or position, can be extracted by the analysis software developed in this paper. Calculations are carried out to discuss the key issues of this MEMS device, and our simulation is verified by diffraction patterns of transparent microparticles on fabricated apertures, recorded via a digital camera.

  8. In-line metrology setup for periodic nanostructures based on sub-wavelength diffraction

    NASA Astrophysics Data System (ADS)

    Kreuzer, Martin; Gomis Bresco, Jordi; Sledzinska, Marianna; Sotomayor Torres, Clivia M.

    2015-09-01

    The analysis of diffracted light from periodic structures is shown to be a versatile metrology technique applicable to inline metrology for periodic nanostructures. We show that 10 nm changes in periodic structures can be traced optically by means of sub-wavelength diffraction. Polymer gratings were fabricated by electron beam lithography. The gratings have a common periodicity of 6 μm, but different line width, ranging from 370 to 550 nm in 10 nm steps. A comparison between the resulting diffraction patterns shows marked differences in intensity which are used to sense nanometre scale deviations in periodic structures.

  9. Plane-wave Fresnel diffraction by elliptic apertures: a Fourier-based approach.

    PubMed

    Borghi, Riccardo

    2014-10-01

    A simple theoretical approach to evaluate the scalar wavefield, produced, within paraxial approximation, by the diffraction of monochromatic plane waves impinging on elliptic apertures or obstacles is presented. We find that the diffracted field can be mathematically described in terms of a Fourier series with respect to an angular variable suitably related to the elliptic parametrization of the observation plane. The convergence features of such Fourier series are analyzed, and a priori truncation criterion is also proposed. Two-dimensional maps of the optical intensity diffraction patterns are then numerically generated and compared, at a visual level, with several experimental pictures produced in the past. The last part of this work is devoted to carrying out an analytical investigation of the diffracted field along the ellipse axis. A uniform approximation is derived on applying a method originally developed by Schwarzschild, and an asymptotic estimate, valid in the limit of small eccentricities, is also obtained via the Maggi-Rubinowicz boundary wave theory.

  10. Diffraction-based optical sensor detection system for capture-restricted environments

    NASA Astrophysics Data System (ADS)

    Khandekar, Rahul M.; Nikulin, Vladimir V.

    2008-04-01

    The use of digital cameras and camcorders in prohibited areas presents a growing problem. Piracy in the movie theaters results in huge revenue loss to the motion picture industry every year, but still image and video capture may present even a bigger threat if performed in high-security locations. While several attempts are being made to address this issue, an effective solution is yet to be found. We propose to approach this problem using a very commonly observed optical phenomenon. Cameras and camcorders use CCD and CMOS sensors, which include a number of photosensitive elements/pixels arranged in a certain fashion. Those are photosites in CCD sensors and semiconductor elements in CMOS sensors. They are known to reflect a small fraction of incident light, but could also act as a diffraction grating, resulting in the optical response that could be utilized to identify the presence of such a sensor. A laser-based detection system is proposed that accounts for the elements in the optical train of the camera, as well as the eye-safety of the people who could be exposed to optical beam radiation. This paper presents preliminary experimental data, as well as the proof-of-concept simulation results.

  11. Evaluation of Laser Based Alignment Algorithms Under Additive Random and Diffraction Noise

    SciTech Connect

    McClay, W A; Awwal, A; Wilhelmsen, K; Ferguson, W; McGee, M; Miller, M

    2004-09-30

    The purpose of the automatic alignment algorithm at the National Ignition Facility (NIF) is to determine the position of a laser beam based on the position of beam features from video images. The position information obtained is used to command motors and attenuators to adjust the beam lines to the desired position, which facilitates the alignment of all 192 beams. One of the goals of the algorithm development effort is to ascertain the performance, reliability, and uncertainty of the position measurement. This paper describes a method of evaluating the performance of algorithms using Monte Carlo simulation. In particular we show the application of this technique to the LM1{_}LM3 algorithm, which determines the position of a series of two beam light sources. The performance of the algorithm was evaluated for an ensemble of over 900 simulated images with varying image intensities and noise counts, as well as varying diffraction noise amplitude and frequency. The performance of the algorithm on the image data set had a tolerance well beneath the 0.5-pixel system requirement.

  12. The Yale Pharyngeal Residue Severity Rating Scale: An Anatomically Defined and Image-Based Tool.

    PubMed

    Neubauer, Paul D; Rademaker, Alfred W; Leder, Steven B

    2015-10-01

    The Yale Pharyngeal Residue Severity Rating Scale was developed, standardized, and validated to provide reliable, anatomically defined, and image-based assessment of post-swallow pharyngeal residue severity as observed during fiberoptic endoscopic evaluation of swallowing (FEES). It is a five-point ordinal rating scale based on residue location (vallecula and pyriform sinus) and amount (none, trace, mild, moderate, and severe). Two expert judges reviewed a total of 261 FEES evaluations and selected a no residue exemplar and three exemplars each of trace, mild, moderate, and severe vallecula and pyriform sinus residue. Hard-copy color images of the no residue, 12 vallecula, and 12 pyriform sinus exemplars were randomized by residue location for hierarchical categorization by 20 raters with a mean of 8.3 years of experience (range 2-27 years) performing and interpreting FEES. Severity ratings for all images were performed by the same 20 raters, 2 weeks apart, and with the order of image presentations randomized. Intra-rater test-retest reliability, inter-rater reliability, and construct validity were determined by pooled multi-category multi-rater kappa statistics. Residue ratings were excellent for intra-rater reliability for vallecula (kappa = 0.957 ± 0.014) and pyriform sinus (kappa = 0.854 ± 0.021); very good to excellent for inter-rater reliability for vallecula (kappa = 0.868 ± 0.011) and pyriform sinus (kappa = 0.751 ± 0.011); and excellent for validity for vallecula (kappa = 0.951 ± 0.014) and pyriform sinus (kappa = 0.908 ± 0.017). Clinical uses include accurate classification of vallecula and pyriform sinus residue severity patterns as none, trace, mild, moderate, or severe for diagnostic purposes, determination of functional therapeutic change, and precise dissemination of shared information. Scientific uses include tracking outcome measures, demonstrating efficacy of interventions to reduce pharyngeal residue, investigating morbidity and mortality

  13. Multiple Bragg diffraction in opal-based photonic crystals: Spectral and spatial dispersion

    NASA Astrophysics Data System (ADS)

    Shishkin, I. I.; Rybin, M. V.; Samusev, K. B.; Golubev, V. G.; Limonov, M. F.

    2014-01-01

    We present an experimental and theoretical study of multiple Bragg diffraction from synthetic opals. An original setup permits us to overcome the problem of the total internal light reflection in an opal film and to investigate the diffraction from both the (111) and (1¯11) systems of planes responsible for the effect. As a result, angle- and frequency-resolved diffraction and transmission measurements create a picture of multiple Bragg diffraction that includes general agreement between dips in the transmission spectra and diffraction peaks for each incident white light angle and a twin-peak structure at frequencies of the photonic stop band edges. Two opposite cases of the interference are discussed: an interference of two narrow Bragg bands that leads to multiple Bragg diffraction with anticrossing regime for dispersion photonic branches and an interference of a narrow Bragg band and broad disorder-induced Mie background that results in a Fano resonance. A good quantitative agreement between the experimental data and calculated photonic band structure has been obtained.

  14. Applications of on-product diffraction-based focus metrology in logic high volume manufacturing

    NASA Astrophysics Data System (ADS)

    Noyes, Ben F.; Mokaberi, Babak; Bolton, David; Li, Chen; Palande, Ashwin; Park, Kevin; Noot, Marc; Kea, Marc

    2016-03-01

    The integration of on-product diffraction-based focus (DBF) capability into the majority of immersion lithography layers in leading edge logic manufacturing has enabled new applications targeted towards improving cycle time and yield. A CD-based detection method is the process of record (POR) for excursion detection. The drawback of this method is increased cycle time and limited sampling due to CD-SEM metrology capacity constraints. The DBFbased method allows the addition of focus metrology samples to the existing overlay measurements on the integrated metrology (IM) system. The result enables the addition of measured focus to the SPC system, allowing a faster excursion detection method. For focus targeting, the current method involves using a dedicated focus-exposure matrix (FEM) on all scanners, resulting in lengthy analysis times and uncertainty in the best focus. The DBF method allows the measurement to occur on the IM system, on a regular production wafer, and at the same time as the exposure. This results in a cycle time gain as well as a less subjective determination of best focus. A third application aims to use the novel onproduct focus metrology data in order to apply per-exposure focus corrections to the scanner. These corrections are particularly effective at the edge of the wafer, where systematic layer-dependent effects can be removed using DBFbased scanner feedback. This paper will discuss the development of a methodology to accomplish each of these applications in a high-volume production environment. The new focus metrology method, sampling schemes, feedback mechanisms and analysis methods lead to improved focus control, as well as earlier detection of failures.

  15. A micro opto-mechanical displacement sensor based on micro-diffraction gratings: design and characterization.

    PubMed

    Accoto, D; Schena, E; Cidda, M; Francomano, M; Saccomandi, P; Silvestri, S

    2013-01-01

    A micro opto-mechanical displacement sensor is here presented. It is constituted by a sensing element based on two overlapped micro-diffraction gratings (MDGs). They present a platinum layer (45 nm of thick) on a glass substrate, a period of 525 µm constituted by a width of 150 µm of platinum separated (71.4% duty cycle). The working principle is based on the modulation of light intensity induced by the relative displacement between the MDGs: when a laser light perpendicularly hits the MDGs, the intensity of the transmitted light is a periodic function of the relative displacement between the two MDGs. A fiber optic is used to transport the transmitted light to a photodetector in order to avoid concerns related to the alignment between the optical components. The sensor's output is the ratio between the light intensity measured by the photodetector during the displacement of the MDGs and largest light intensity values measured in the whole range of measurement, therefore, it is lower than 1. The proposed sensor allows to discriminate displacement lower than 10 µm, using a cost effective micro-fabrication process implemented by the technique of Lift-Off. It shows a good linear behaviour in two ranges covering about one half of the MDGs period. Within the linear ranges it shows high sensitivity (about 0.5%/µm) and good accuracy (lower than 4% in the whole range of calibration); furthermore, the results show that a design with a duty cycle of 50% overcomes the marked decrease of sensitivity in a range of measurement corresponding to a grating period.

  16. Sound Velocity and Diffraction Intensity Measurements Based on Raman-Nath Theory of the Interaction of Light and Ultrasound

    ERIC Educational Resources Information Center

    Neeson, John F.; Austin, Stephen

    1975-01-01

    Describes a method for the measurement of the velocity of sound in various liquids based on the Raman-Nath theory of light-sound interaction. Utilizes an analog computer program to calculate the intensity of light scattered into various diffraction orders. (CP)

  17. An Inquiry-Based Project Focused on the X-Ray Powder Diffraction Analysis of Common Household Solids

    ERIC Educational Resources Information Center

    Hulien, Molly L.; Lekse, Jonathan W.; Rosmus, Kimberly A.; Devlin, Kasey P.; Glenn, Jennifer R.; Wisneski, Stephen D.; Wildfong, Peter; Lake, Charles H.; MacNeil, Joseph H.; Aitken, Jennifer A.

    2015-01-01

    While X-ray powder diffraction (XRPD) is a fundamental analytical technique used by solid-state laboratories across a breadth of disciplines, it is still underrepresented in most undergraduate curricula. In this work, we incorporate XRPD analysis into an inquiry-based project that requires students to identify the crystalline component(s) of…

  18. Synchrotron-based crystal structure, associated morphology of snail and bivalve shells by X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Rao, D. V.; Gigante, G. E.; Kumar, Y. Manoj; Cesareo, R.; Brunetti, A.; Schiavon, N.; Akatsuka, T.; Yuasa, T.; Takeda, T.

    2016-10-01

    Synchrotron-based high-resolution X-ray powder diffraction spectra from the body parts of a snail and bivalve (CaCO3), have been recorded with Pilatus area detector. Experiments were performed at Desy, Hamburg, Germany, utilizing the Resonant and Diffraction beamline (P9), with 15 keV X-rays (λ=0.82666 Å). The external shell of these living organisms, is composed of calcium carbonate, which carries strong biological signal. It consists of some light elements, such as, Ca, C and O, which constitute part of the soft tissue and other trace elements. The knowledge of these diffraction patterns and hence the understanding of structures at molecular level are enormous. The application of synchrotron radiation to powder diffraction is well suited for samples of biological nature via changes in their patterns and also to investigate crystallographic phase composition. With the use of Rietveld refinement procedure, to the high-resolution diffraction spectra, we were able to extract the lattice parameters of orthorhombic polymorph of CaCO3, the most abundant mineral produced by these living organisms. The small size of the crystallite is a very important factor related to the biological structure. The natural model presents a combination of organic and inorganic phases with nanometer size. For the present study, we also used the scanning electron microscopy (SEM) to explore the associated morphology of the snail and bivalve.

  19. Computer-based classification of bacteria species by analysis of their colonies Fresnel diffraction patterns

    NASA Astrophysics Data System (ADS)

    Suchwalko, Agnieszka; Buzalewicz, Igor; Podbielska, Halina

    2012-01-01

    In the presented paper the optical system with converging spherical wave illumination for classification of bacteria species, is proposed. It allows for compression of the observation space, observation of Fresnel patterns, diffraction pattern scaling and low level of optical aberrations, which are not possessed by other optical configurations. Obtained experimental results have shown that colonies of specific bacteria species generate unique diffraction signatures. Analysis of Fresnel diffraction patterns of bacteria colonies can be fast and reliable method for classification and recognition of bacteria species. To determine the unique features of bacteria colonies diffraction patterns the image processing analysis was proposed. Classification can be performed by analyzing the spatial structure of diffraction patterns, which can be characterized by set of concentric rings. The characteristics of such rings depends on the bacteria species. In the paper, the influence of basic features and ring partitioning number on the bacteria classification, is analyzed. It is demonstrated that Fresnel patterns can be used for classification of following species: Salmonella enteritidis, Staplyococcus aureus, Proteus mirabilis and Citrobacter freundii. Image processing is performed by free ImageJ software, for which a special macro with human interaction, was written. LDA classification, CV method, ANOVA and PCA visualizations preceded by image data extraction were conducted using the free software R.

  20. Diffractive optics in large sizes: computer-generated holograms (CGH) based on Bayfol HX photopolymer

    NASA Astrophysics Data System (ADS)

    Bruder, Friedrich-Karl; Fäcke, Thomas; Hagen, Rainer; Hönel, Dennis; Kleinschmidt, Tim Patrick; Orselli, Enrico; Rewitz, Christian; Rölle, Thomas; Walze, Günther

    2015-03-01

    Volume Holographic Optical Elements (vHOE) offer angular and spectral Bragg selectivity that can be tuned by film thickness and holographic recording conditions. With the option to integrate complex optical function in a very thin plastic layer formerly heavy refractive optics can be made thin and lightweight especially for large area applications like liquid crystal displays, projection screens or photovoltaic. Additionally their Bragg selectivity enables the integration of several completely separated optical functions in the same film. The new instant developing photopolymer film (Bayfol® HX) paves the way towards new cost effective diffractive large optics, due to its easy holographic recording and environmental stability. A major bottleneck for large area applications has been the master hologram recording which traditionally needs expensive, large high precision optical equipment and high power laser with long coherence length. Further the recording setup needs to be rearranged for a change in optical design. In this paper we describe an alternative method for large area holographic master recording, using standard optics and low power lasers in combination with an x, y-translation stage. In this setup small sub-holograms generated by a phase only spatial light modulator (SLM) are recorded next to each other to generate a large size vHOE. The setup is flexible to generate various types of HOEs without the need of a change in the mechanical and optical construction by convenient SLM programming. One Application example and parameter studies for printed vHOEs based on Bayfol® HX Photopolymer will be given.

  1. Optical cryptography topology based on a three-dimensional particle-like distribution and diffractive imaging.

    PubMed

    Chen, Wen; Chen, Xudong

    2011-05-01

    In recent years, coherent diffractive imaging has been considered as a promising alternative for information retrieval instead of conventional interference methods. Coherent diffractive imaging using the X-ray light source has opened up a new research perspective for the measurement of non-crystalline and biological specimens, and can achieve unprecedentedly high resolutions. In this paper, we show how a three-dimensional (3D) particle-like distribution and coherent diffractive imaging can be applied for a study of optical cryptography. An optical multiple-random-phase-mask encoding approach is used, and the plaintext is considered as a series of particles distributed in a 3D space. A topology concept is also introduced into the proposed optical cryptosystem. During image decryption, a retrieval algorithm is developed to extract the plaintext from the ciphertexts. In addition, security and advantages of the proposed optical cryptography topology are also analyzed.

  2. Optical pendulum effect in one-dimensional diffraction-thick porous silicon based photonic crystals

    NASA Astrophysics Data System (ADS)

    Novikov, V. B.; Svyakhovskiy, S. E.; Maydykovskiy, A. I.; Murzina, T. V.; Mantsyzov, B. I.

    2015-11-01

    We present the realization of the multiperiodic optical pendulum effect in 1D porous silicon photonic crystals (PhCs) under dynamical Bragg diffraction in the Laue scheme. The diffraction-thick PhC contained 360 spatial periods with a large variation of the refractive index of adjacent layers of 0.4. The experiments reveal switching of the light leaving the PhC between the two spatial directions, which correspond to Laue diffraction maxima, as the fundamental wavelength or polarization of the incident light is varied. A similar effect can be achieved when the temperature of the sample or the intensity of the additional laser beam illuminating the crystal are changed. We show that in our PhC structures, the spectral period of the pendulum effect is down to 5 nm, while the thermal period is about 10 °C.

  3. Optical pendulum effect in one-dimensional diffraction-thick porous silicon based photonic crystals

    SciTech Connect

    Novikov, V. B. Svyakhovskiy, S. E.; Maydykovskiy, A. I.; Murzina, T. V.; Mantsyzov, B. I.

    2015-11-21

    We present the realization of the multiperiodic optical pendulum effect in 1D porous silicon photonic crystals (PhCs) under dynamical Bragg diffraction in the Laue scheme. The diffraction-thick PhC contained 360 spatial periods with a large variation of the refractive index of adjacent layers of 0.4. The experiments reveal switching of the light leaving the PhC between the two spatial directions, which correspond to Laue diffraction maxima, as the fundamental wavelength or polarization of the incident light is varied. A similar effect can be achieved when the temperature of the sample or the intensity of the additional laser beam illuminating the crystal are changed. We show that in our PhC structures, the spectral period of the pendulum effect is down to 5 nm, while the thermal period is about 10 °C.

  4. Multiwavelength anomalous diffraction analyses of protein structures based on xenon and selenium resonances

    NASA Astrophysics Data System (ADS)

    Slama, Betty Nicole

    The 'phase problem' is central to X-ray crystallography, and multiwavelength anomalous diffraction (MAD) provides an elegant and broadly accessible solution. In the first part, the use of MAD at the xenon L3 edge is explored, as an alternative to the well established selenium K-edge phasing. In the second part, the structure of the bacterial protein Vibrio cholerae LuxQ, part of a two component signaling system involved in quorum sensing, is solved and analyzed. Keywords: anomalous scattering, x-ray diffraction, phasing, protein structure.

  5. Optimizing the diffraction efficiency of LCOS-based holography with anomalous reflection by gradient meta-surface

    NASA Astrophysics Data System (ADS)

    Shen, Chuan; Liu, Kaifeng; Wei, Sui; Ni, Lei; Wang, Hao

    2015-05-01

    Meta-surface offers an innovative approach to manipulate light with anomalous capabilities. We discuss the possibility of inserting a specially designed gradient meta-surface into the pixel architecture of the liquid crystal on silicon (LCOS) for the purpose of optimizing the diffraction efficiency of LCOS-based holography. The pixels in LCOS with feature size approaching the order of visible light wavelength could provide large diffraction angle, unfortunately, scaling down the pixel size would reduce the efficiency of the first diffraction we desired. The metal-insulator-metal (MIM) structure served as the unit cell of meta-surface consists of three layer, i.e., the subwavelength metal nanobrick with varying geometrical parameter and the continuous metal film separated by the insulator layer. A linear phase gradient is exhibited by the unit cells in each pixel period. When illuminated by a polarized incident light, the MIM structure, where a magnetic resonance is created at a particular frequency, can offer an anomalous reflection with high-efficiency and acts as a flat blazed grating. Finally, the light are supposed be diverted to the desired first diffraction. The properties of potential metal, such as Au, Ag, and Al, served as the plasmonic material and suitable insulator have been studied to configure the MIM structure accurately. Investigations are numerically carried out to observe the effects on the distribution of liquid crystal director with TechWiz Software and to obtain the relative diffraction efficiency by using FDTD software. Compared with the conventional LCOS device, the optimization of the diffraction efficiency has been achieved by our proposed structure.

  6. Far-field sub-diffraction focusing lens based on binary amplitude-phase mask for linearly polarized light.

    PubMed

    Chen, Gang; Zhang, Kun; Yu, Anping; Wang, Xianyou; Zhang, Zhihai; Li, Yuyan; Wen, Zhongquan; Li, Chen; Dai, Luru; Jiang, Senling; Lin, Feng

    2016-05-16

    Planar lenses are attractive photonic devices due to its minimized size and easy to integrate. However, planar lenses designed in traditional ways are restricted by the diffraction limit. They have difficulties in further reducing the focal spot size beyond the diffraction limit. Super-oscillation provides a possible way to solve the problem. However, lenses based on super-oscillation have always been affected by huge sidelobes, which resulted in limited field of view and difficulties in real applications. To address the problem, in the paper, a far-field sub-diffraction lens based on binary amplitude-phase mask was demonstrated under illumination of linearly polarized plane wave at wavelength 632.8 nm. The lens realized a long focal length of 148λ (94 µm), and the full width at half maximum of the focal line was 0.406λ, which was super-oscillatory. More important is that such a flat lens has small sidelobes and wide field of view. Within the measured range of [-132λ, + 120λ], the maximum sidelobe observed on the focal plane was less than 22% of the central peak. Such binary amplitude-phase planar lens can also be extended to long focal length far-field sub-diffraction focusing lens for other spectrum ranges.

  7. Prediction of contact residue pairs based on co-substitution between sites in protein structures.

    PubMed

    Miyazawa, Sanzo

    2013-01-01

    Residue-residue interactions that fold a protein into a unique three-dimensional structure and make it play a specific function impose structural and functional constraints in varying degrees on each residue site. Selective constraints on residue sites are recorded in amino acid orders in homologous sequences and also in the evolutionary trace of amino acid substitutions. A challenge is to extract direct dependences between residue sites by removing phylogenetic correlations and indirect dependences through other residues within a protein or even through other molecules. Rapid growth of protein families with unknown folds requires an accurate de novo prediction method for protein structure. Recent attempts of disentangling direct from indirect dependences of amino acid types between residue positions in multiple sequence alignments have revealed that inferred residue-residue proximities can be sufficient information to predict a protein fold without the use of known three-dimensional structures. Here, we propose an alternative method of inferring coevolving site pairs from concurrent and compensatory substitutions between sites in each branch of a phylogenetic tree. Substitution probability and physico-chemical changes (volume, charge, hydrogen-bonding capability, and others) accompanied by substitutions at each site in each branch of a phylogenetic tree are estimated with the likelihood of each substitution, and their direct correlations between sites are used to detect concurrent and compensatory substitutions. In order to extract direct dependences between sites, partial correlation coefficients of the characteristic changes along branches between sites, in which linear multiple dependences on feature vectors at other sites are removed, are calculated and used to rank coevolving site pairs. Accuracy of contact prediction based on the present coevolution score is comparable to that achieved by a maximum entropy model of protein sequences for 15 protein families

  8. Diffraction techniques in engineering applications

    SciTech Connect

    Kozarczek, K.J.; Hubbard, C.R.; Watkins, T.R.; Wang, X.L.; Spooner, S.

    1995-12-31

    Diffraction techniques applied to crystalline materials provide quantitative information about the crystallographic structure and mechanical condition of the material. Those two characteristics influence the chemical, physical, and mechanical properties of a Component. A concerted application of x-ray and neutron diffraction allows one to comprehensively study the bulk and subsurface variations of such material characteristics as crystallographic texture, residual stress, and cold work. The Residual Stress User Center at the Oak Ridge National Laboratory offers academic and industrial researchers both neutron and x-ray diffraction capabilities. Recent examples of the application of work related to thin film, metal, ceramic and composite material technologies are presented.

  9. Ophthalmic compensation of visual ametropia based on a programmable diffractive lens

    NASA Astrophysics Data System (ADS)

    Millán, Maria S.; Pérez-Cabré, Elisabet; Romero, Lenny A.; Ramírez, Natalia

    2013-11-01

    Pixelated liquid crystal displays have been widely used as spatial light modulators to implement programmable diffractive optical elements (DOEs), particularly diffractive lenses. Many different applications of such components have been developed in information optics and optical processors that take advantage of their properties of great flexibility, easy and fast refreshment, and multiplexing capability in comparison with equivalent conventional refractive lenses. In this paper, we explore the application of programmable diffractive lenses displayed on the pixelated screen of a liquid crystal on silicon spatial light modulator (LCoS-SLM) to ophthalmic optics. In particular, we consider the use of programmable diffractive lenses for the visual compensation of some refractive errors (myopia, hyperopia). The theoretical principles of compensation are described and sketched using geometrical optics and paraxial ray tracing. A series of experiments with artificial eye in optical bench are conducted to analyze the compensation accuracy in terms of optical power and to compare the results with those obtained by means of conventional ophthalmic lenses. Practical considerations oriented to feasible applications are provided.

  10. Generation of High-Density Electrons Based on Plasma Grating Induced Bragg Diffraction in Air

    SciTech Connect

    Shi Liping; Li Wenxue; Wang Yongdong; Lu Xin; Ding Liang'en; Zeng Heping

    2011-08-26

    Efficient nonlinear Bragg diffraction was observed as an intense infrared femtosecond pulse was focused on a plasma grating induced by interference between two ultraviolet femtosecond laser pulses in air. The preformed electrons inside the plasma grating were accelerated by subsequent intense infrared laser pulses, inducing further collisional ionization and significantly enhancing the local electron density.

  11. Plane-wave Fresnel diffraction by elliptic apertures: a Fourier-based approach.

    PubMed

    Borghi, Riccardo

    2014-10-01

    A simple theoretical approach to evaluate the scalar wavefield, produced, within paraxial approximation, by the diffraction of monochromatic plane waves impinging on elliptic apertures or obstacles is presented. We find that the diffracted field can be mathematically described in terms of a Fourier series with respect to an angular variable suitably related to the elliptic parametrization of the observation plane. The convergence features of such Fourier series are analyzed, and a priori truncation criterion is also proposed. Two-dimensional maps of the optical intensity diffraction patterns are then numerically generated and compared, at a visual level, with several experimental pictures produced in the past. The last part of this work is devoted to carrying out an analytical investigation of the diffracted field along the ellipse axis. A uniform approximation is derived on applying a method originally developed by Schwarzschild, and an asymptotic estimate, valid in the limit of small eccentricities, is also obtained via the Maggi-Rubinowicz boundary wave theory. PMID:25401234

  12. Axial focusing characteristics of diffractive micro-lenses based on a rigorous electromagnetic theory

    NASA Astrophysics Data System (ADS)

    Feng, Di; Yan, Yingbai; Jin, Guofan; Fan, Shoushan

    2004-12-01

    In order to determine the assembling error at the receiving plane and to obtain the maximum energy efficiency, it is necessary to study the axial focusing characteristics of diffractive micro-lenses such as the focal depth and the focal shift. When the diffractive optical elements' features are of the order of or smaller than the wavelength of the incident illumination, their electromagnetic characteristics must be considered. By using a two-dimensional finite-difference time-domain (FDTD) method, we present a rigorous electromagnetic analysis of diffractive micro-lenses that are finite in extent, in the case of a normally incident light wave. Compared with the scalar theory, the axial intensity distributions of diffractive micro-lenses are analysed rigorously, for different incidence polarizations (TE polarization and TM polarization), different profile structures (continuous profile, 16-level profile, 8-level profile, and 2-level profile) and different f-numbers of lenses. The numerical results show that the focal shifts calculated by the electromagnetic theory are larger than those made by the scalar theory, and the focal depths calculated by these two methods are basically consistent. The focal depth and the focal shift will increase when the f-number increases, for both the rigorous electromagnetic theory and the scalar theory.

  13. Stabilization of geothermal residues by encapsulation in portland cement-based composites

    SciTech Connect

    Webster, R.P.; Kukacka, L.E.

    1988-05-01

    Presented are the results from a laboratory test program conducted to identify and evaluate materials for converting hazardous geothermal residues to a non-hazardous and potentially usable form. Results indicate that the residues can be effectively incorporated, as a fine aggregate, into portland cement-based composites. Five geothermal residues obtained from sites in the Salton Sea area of California were evaluated. Three of these were classified as hazardous. After mixing with cement, the leach rates were all well below specified levels. Although structural-grade composites were produced, gradual reductions in properties with time up to 1 yr were noted. This indicates ongoing chemical reactions between the cement paste and the constituents of the residues. Further research is necessary before the composites could be considered for use in structural applications. 3 refs., 8 tabs.

  14. Crack prediction in EB-PVD thermal barrier coatings based on the simulation of residual stresses

    NASA Astrophysics Data System (ADS)

    Chen, J. W.; Zhao, Y.; Liu, S.; Zhang, Z. Z.; Ma, J.

    2016-07-01

    Thermal barrier coatings systems (TBCs) are widely used in the field of aerospace. The durability and insulating ability of TBCs are highly dependent on the residual stresses of top coatings, thus the investigation of the residual stresses is helpful to understand the failure mechanisms of TBCs. The simulation of residual stresses evolution in electron beam physical vapor deposition (EB-PVD) TBCs is described in this work. The interface morphology of TBCs subjected to cyclic heating and cooling is observed using scanning electron microscope (SEM). An interface model of TBCs is established based on thermal elastic-plastic finite method. Residual stress distributions in TBCs are obtained to reflect the influence of interfacial roughness. Both experimental and simulation results show that it is feasible to predict the crack location by stress analysis, which is crucial to failure prediction.

  15. Production of apple-based baby food: changes in pesticide residues.

    PubMed

    Kovacova, Jana; Kocourek, Vladimir; Kohoutkova, Jana; Lansky, Miroslav; Hajslova, Jana

    2014-01-01

    Apples represent the main component of most fruit-based baby food products. Since not only fruit from organic farming, but also conventionally grown fruit is used for baby food production, the occurrence of pesticide residues in the final product is of high concern. To learn more about the fate of these hazardous compounds during processing of contaminated raw material, apples containing altogether 21 pesticide residues were used for preparation of a baby food purée both in the household and at industrial scale (in the baby food production facility). Within both studies, pesticide residues were determined in raw apples as well as in final products. Intermediate product and by-product were also analysed during the industrial process. Determination of residues was performed by a sensitive multi-detection analytical method based on liquid or gas chromatography coupled with mass spectrometry. The household procedure involved mainly the cooking of unpeeled apples, and the decrease of residues was not extensive enough for most of the studied pesticides; only residues of captan, dithianon and thiram dropped significantly (processing factors less than 0.04). On the other hand, changes in pesticide levels were substantial for all tested pesticides during apple processing in the industrial baby food production facility. The most important operation affecting the reduction of residues was removal of the by-products after pulping (rest of the peel, stem, pips etc.), while subsequent sterilisation has an insignificant effect. Also in this case, captan, dithianon and thiram were identified as pesticides with the most evident decrease of residues.

  16. Free-Suspension Residual Flexibility Testing of Space Station Pathfinder: Comparison to Fixed-Base Results

    NASA Technical Reports Server (NTRS)

    Tinker, Michael L.

    1998-01-01

    Application of the free-suspension residual flexibility modal test method to the International Space Station Pathfinder structure is described. The Pathfinder, a large structure of the general size and weight of Space Station module elements, was also tested in a large fixed-base fixture to simulate Shuttle Orbiter payload constraints. After correlation of the Pathfinder finite element model to residual flexibility test data, the model was coupled to a fixture model, and constrained modes and frequencies were compared to fixed-base test. modes. The residual flexibility model compared very favorably to results of the fixed-base test. This is the first known direct comparison of free-suspension residual flexibility and fixed-base test results for a large structure. The model correlation approach used by the author for residual flexibility data is presented. Frequency response functions (FRF) for the regions of the structure that interface with the environment (a test fixture or another structure) are shown to be the primary tools for model correlation that distinguish or characterize the residual flexibility approach. A number of critical issues related to use of the structure interface FRF for correlating the model are then identified and discussed, including (1) the requirement of prominent stiffness lines, (2) overcoming problems with measurement noise which makes the antiresonances or minima in the functions difficult to identify, and (3) the use of interface stiffness and lumped mass perturbations to bring the analytical responses into agreement with test data. It is shown that good comparison of analytical-to-experimental FRF is the key to obtaining good agreement of the residual flexibility values.

  17. Reflectance Prediction Modelling for Residual-Based Hyperspectral Image Coding

    PubMed Central

    Xiao, Rui; Gao, Junbin; Bossomaier, Terry

    2016-01-01

    A Hyperspectral (HS) image provides observational powers beyond human vision capability but represents more than 100 times the data compared to a traditional image. To transmit and store the huge volume of an HS image, we argue that a fundamental shift is required from the existing “original pixel intensity”-based coding approaches using traditional image coders (e.g., JPEG2000) to the “residual”-based approaches using a video coder for better compression performance. A modified video coder is required to exploit spatial-spectral redundancy using pixel-level reflectance modelling due to the different characteristics of HS images in their spectral and shape domain of panchromatic imagery compared to traditional videos. In this paper a novel coding framework using Reflectance Prediction Modelling (RPM) in the latest video coding standard High Efficiency Video Coding (HEVC) for HS images is proposed. An HS image presents a wealth of data where every pixel is considered a vector for different spectral bands. By quantitative comparison and analysis of pixel vector distribution along spectral bands, we conclude that modelling can predict the distribution and correlation of the pixel vectors for different bands. To exploit distribution of the known pixel vector, we estimate a predicted current spectral band from the previous bands using Gaussian mixture-based modelling. The predicted band is used as the additional reference band together with the immediate previous band when we apply the HEVC. Every spectral band of an HS image is treated like it is an individual frame of a video. In this paper, we compare the proposed method with mainstream encoders. The experimental results are fully justified by three types of HS dataset with different wavelength ranges. The proposed method outperforms the existing mainstream HS encoders in terms of rate-distortion performance of HS image compression. PMID:27695102

  18. Prediction of protein secondary structure based on residue pair types and conformational states using dynamic programming algorithm.

    PubMed

    Sadeghi, Mehdi; Parto, Sahar; Arab, Shahriar; Ranjbar, Bijan

    2005-06-20

    We have used a statistical approach for protein secondary structure prediction based on information theory and simultaneously taking into consideration pairwise residue types and conformational states. Since the prediction of residue secondary structure by one residue window sliding make ambiguity in state prediction, we used a dynamic programming algorithm to find the path with maximum score. A score system for residue pairs in particular conformations is derived for adjacent neighbors up to ten residue apart in sequence. The three state overall per-residue accuracy, Q3, of this method in a jackknife test with dataset created from PDBSELECT is more than 70%.

  19. Approach to improve beam quality of inter-satellite optical communication system based on diffractive optical elements.

    PubMed

    Tan, Liying; Yu, Jianjie; Ma, Jing; Yang, Yuqiang; Li, Mi; Jiang, Yijun; Liu, Jianfeng; Han, Qiqi

    2009-04-13

    For inter-satellite optical communication transmitter with reflective telescope of two-mirrors on axis, a large mount of the transmitted energy will be blocked by central obscuration of the secondary mirror. In this paper, a novel scheme based on diffractive optical element (DOE) is introduced to avoid it. This scheme includes one diffractive beam shaper and another diffractive phase corrector, which can diffract the obscured part of transmitted beam into the domain unobscured by the secondary mirror. The proposed approach is firstly researched with a fixed obscuration ratio of 1/4. Numerical simulation shows that the emission efficiency of new figuration is 99.99%; the beam divergence from the novel inter-satellite optical communication transmitter is unchanged; and the peak intensity of receiver plane is increased about 31% compared with the typical configuration. Then the intensy patterns of receiver plane are analyzed with various obscuration ratio, the corresponding numerical modelling reveals that the intensity patterns with various obscuration ratio are nearly identical, but the amplify of relative peak intensity is getting down with the growth of obscuration ratio. This work can improve the beam quality of inter-satellite optical communication system without affecting any other functionality.

  20. Mindful Mood Balance: A Case Report of Web-Based Treatment of Residual Depressive Symptoms

    PubMed Central

    Felder, Jennifer; Dimidjian, Sona; Beck, Arne; Boggs, Jennifer M; Segal, Zindel

    2014-01-01

    Residual depressive symptoms are associated with increased risk for relapse and impaired functioning. Although there is no definitive treatment for residual depressive symptoms, Mindfulness-Based Cognitive Therapy has been shown to be effective, but access is limited. Mindful Mood Balance (MMB), a Web-based adaptation of Mindfulness-Based Cognitive Therapy, was designed to address this care gap. In this case study, we describe a composite case that is representative of the course of intervention with MMB and its implementation in a large integrated delivery system. Specifically, we describe the content of each of eight weekly sessions, and the self-management skills developed by participating in this program. MMB may be a cost-effective and scalable option in primary care for increasing access to treatments for patients with residual depressive symptoms. PMID:25141988

  1. CCD-based X-ray area detector for time-resolved diffraction experiments.

    PubMed

    Yagi, Naoto; Inoue, Katsuaki; Oka, Toshihiko

    2004-11-01

    A fast X-ray area detector for diffraction, scattering and imaging experiments at microsecond to millisecond time resolution has been developed. The key element of the detector is a fast (291 frames s(-1)) framing camera with three CCDs. A prism forms identical images on the CCDs and the frame rate is increased three times by reading them alternately. In order to convert X-rays into visible light that is detectable with the CCDs, an X-ray image intensifier is used. The camera can also be used with a high-resolution X-ray detector. In both cases it was found to be important to use a phosphor with a short decay time to fully make use of the high-speed framing capability of the camera. Preliminary results of a fibre diffraction experiment on a skeletal muscle and coronary angiography are presented.

  2. Determination of the diameter of an isolated surface defect based on Fraunhofer diffraction.

    PubMed

    Klingsporn, P E

    1980-05-01

    When an isolated circular defect on an otherwise very smooth reflective surface is illuminated at normal incidence by coherent parallel light, a Fraunhofer diffraction pattern from the defect can be observed in the transverse plane in which a lens focuses the light retroreflected from a defect-free surface. The ratio of the intensity when the defect is illuminated to the intensity in the absence of the defect vs distance r from the center of the focused light spot exhibits a maximum at some distance r = r(m) in the interval 0 < r < r(1 min), where r(1) min is the radius of the central bright spot in the defect diffraction pattern. On the basis of Fraunhofer diffraction, a relation was derived from which the diameter of the defect can be calculated by substituting in the measured distance r(m) at which the ratio of intensity when the defect is present to the intensity from a defect-free surface is a maximum. Experimental data were obtained verifying the theory.

  3. Residual Motion and Duty Time in Respiratory Gating Radiotherapy Using Individualized or Population-Based Windows

    SciTech Connect

    Fuji, Hiroshi Asada, Yoshihiro; Numano, Masumi; Yamashita, Haruo; Nishimura, Tetsuo; Hashimoto, Takayuki; Harada, Hideyuki; Asakura, Hirofumi; Murayama, Shigeyuki

    2009-10-01

    Purpose: The efficiency and precision of respiratory gated radiation therapy for tumors is affected by variations in respiration-induced tumor motion. We evaluated the use of individualized and population-based parameters for such treatment. Methods and Materials: External respiratory signal records and images of respiration-induced tumor motion were obtained from 42 patients undergoing respiratory gated radiation therapy for liver tumors. Gating window widths were calculated for each patient, with 2, 4, and 10 mm of residual motion, and the mean was defined as the population-based window width. Residual motions based on population-based and predefined window widths were compared. Duty times based on whole treatment sessions, at various window levels, were calculated. The window level giving the longest duty time was defined as the individualized most efficient level (MEL). MELs were also calculated based on the first 10 breathing cycles. The duty times for population-based MELs (defined as mean MELs) and individualized MELs were compared. Results: Tracks of respiration-induced tumor motion ranged from 3 to 50 mm. Half of the patients had larger actual residual motions than the assigned residual motions. Duty times were greater when based on individualized, rather than population-based, window widths. The MELs established during whole treatment sessions for 2 mm and 4 mm of residual motion gave significantly increased duty times, whereas those calculated using the first 10 breathing cycles showed only marginal increases. Conclusions: Using individualized window widths and levels provided more precise and efficient respiratory gated radiation therapy. However, methods for predicting individualized window levels before treatment remain to be explored.

  4. Preliminary design of a zone plate based hard X-ray monochromatic diffraction nanoprobe for materials studies at APS

    NASA Astrophysics Data System (ADS)

    Cai, Zhonghou; Liu, Wenjun; Tischler, Jonathan Z.; Shu, Deming; Xu, Ruqing; Schmidt, Oliver

    2013-09-01

    Aiming at studies of the micro/nano-structures of a broad range materials and electronic devices, Advance Photon Source (APS) is developing a dedicated diffraction nanoprobe (DNP) beamline for the needs arising from a multidiscipline research community. As a part of the APS Upgrade Project, the planed facility, named Sub-micron 3-D Diffraction (S3DD) beamline1, integrates the K-B mirror based polychromatic Laue diffraction and the Fresnel zone-plate based monochromatic diffraction techniques that currently support 3D/2D microdiffraction programs at the 34-ID-E and 2-ID-D of the APS, respectively. Both diffraction nanoprobes are designed to have a 50-nm or better special resolution. The zone-plate based monochromatic DNP has been preliminarily designed and will be constructed at the sector 34-ID. It uses an APS-3.0-cm period or APS-3.3-cm period undulator, a liquid-nitrogen cooled mirror as its first optics, and a water cooled small gap silicon double-crystal monochromator with an energy range of 5-30 keV. A set of zone plates have been designed to optimize for focusing efficiency and the working distance based on the attainable beamline length and the beam coherence. To ensure the nanoprobe performance, high stiffness and high precision flexure stage systems have been designed or demonstrated for optics mounting and sample scanning, and high precision temperature control of the experimental station will be implemented to reduce thermal instability. Designed nanoprobe beamline has a good management on thermal power loading on optical components and allows high degree of the preservation of beam brilliance for high focal flux and coherence. Integrated with variety of X-ray techniques, planed facility provides nano-XRD capability with the maximum reciprocal space accessibility and allows micro/nano-spectroscopy studies with K-edge electron binding energies of most elements down to Vanadium in the periodic table. We will discuss the preliminary design of the zone

  5. Covariance of lucky images for increasing objects contrast: diffraction-limited images in ground-based telescopes

    NASA Astrophysics Data System (ADS)

    Cagigal, Manuel P.; Valle, Pedro J.; Colodro-Conde, Carlos; Villó-Pérez, Isidro; Pérez-Garrido, Antonio

    2016-01-01

    Images of stars adopt shapes far from the ideal Airy pattern due to atmospheric density fluctuations. Hence, diffraction-limited images can only be achieved by telescopes without atmospheric influence, e.g. spatial telescopes, or by using techniques like adaptive optics or lucky imaging. In this paper, we propose a new computational technique based on the evaluation of the COvariancE of Lucky Images (COELI). This technique allows us to discover companions to main stars by taking advantage of the atmospheric fluctuations. We describe the algorithm and we carry out a theoretical analysis of the improvement in contrast. We have used images taken with 2.2-m Calar Alto telescope as a test bed for the technique resulting that, under certain conditions, telescope diffraction limit is clearly reached.

  6. Optical study of a spectrum splitting solar concentrator based on a combination of a diffraction grating and a Fresnel lens

    SciTech Connect

    Michel, Céline Habraken, Serge; Loicq, Jérôme; Thibert, Tanguy

    2015-09-28

    This paper presents recent improvements of our new solar concentrator design for space application. The concentrator is based on a combination of a diffraction grating (blazed or lamellar) coupled with a Fresnel lens. Thanks to this diffractive/refractive combination, this optical element splits spatially and spectrally the light and focus approximately respectively visible light and IR light onto electrically independent specific cells. It avoid the use of MJs cells and then also their limitations like current matching and lattice matching conditions, leading theoretically to a more tolerant system. The concept is reminded, with recent optimizations, ideal and more realistic results, and the description of an experimental realization highlighting the feasibility of the concept and the closeness of theoretical and experimental results.

  7. A quantitative method for measurement of HL-60 cell apoptosis based on diffraction imaging flow cytometry technique

    PubMed Central

    Yang, Xu; Feng, Yuanming; Liu, Yahui; Zhang, Ning; Lin, Wang; Sa, Yu; Hu, Xin-Hua

    2014-01-01

    A quantitative method for measurement of apoptosis in HL-60 cells based on polarization diffraction imaging flow cytometry technique is presented in this paper. Through comparative study with existing methods and the analysis of diffraction images by a gray level co-occurrence matrix algorithm (GLCM), we found 4 GLCM parameters of contrast (CON), cluster shade (CLS), correlation (COR) and dissimilarity (DIS) exhibit high sensitivities as the apoptotic rates. It was further demonstrated that the CLS parameter correlates significantly (R2 = 0.899) with the degree of nuclear fragmentation and other three parameters showed a very good correlations (R2 ranges from 0.69 to 0.90). These results demonstrated that the new method has the capability for rapid and accurate extraction of morphological features to quantify cellular apoptosis without the need for cell staining. PMID:25071957

  8. Vector-based synthesis of finite aperiodic diffractive micro-optical elements with subwavelength structures as beam deflectors

    NASA Astrophysics Data System (ADS)

    Feng, Di; Yan, Yingbai; Tan, Qiaofeng

    2003-09-01

    An iterative optimization-based synthesis algorithm has been presented for the design of diffractive micro-optical elements (DMOE's) with subwavelength structures as beam controllers. The DMOE's with subwavelength structures only require single step fabrication, but the subwavelength and aperiodic nature of the DMOE's prevent the use of scalar diffraction theory and the use of coupled-wave theory. We apply the finite-difference time-domain (FDTD) method as the vector model and the iterative plane wave spectrum algorithm (IPWS) as the synthesis algorithm, which can make the design of DMOE's in reasonable time frames. The IPWS, the FDTD method, the plane wave spectrum propagation method have been discussed and a beam deflector with subwavelength structures has been designed.

  9. Visible light dynamical diffraction in a 1-D photonic crystal-based interferometer with an extremely thin spacer layer

    NASA Astrophysics Data System (ADS)

    Prudnikov, I. R.

    2016-01-01

    Properties of light diffraction in a Fabry-Pérot-like interferometer composed of two 1-D photonic crystals and a nanometer-thick spacer layer are analytically investigated. It is shown that the resonant enhancement of light wave intensity in such a layer is possible because of light dynamical diffraction from the photonic crystals of the interferometer. Numerical simulations of (i) light reflectivity and transmittance curves of the interferometer having an ultra-thin spacer layer (its thickness changes from less than 1 nm to about 10 nm) and (ii) the resonant distribution of the light wave intensity in the vicinity of the layer are performed. Based on the numerical simulations, potentialities for the determination of the structural parameters (e.g., thicknesses and refraction indexes) of ultra-thin spacer films are discussed. A difference is found to appear in resonant intensity enhancements inside the ultra-thin spacer layers between s- and p-polarized light waves.

  10. Design of fixed correctors used in conformal optical system based on diffractive optical elements.

    PubMed

    Zhang, Wang; Zuo, Baojun; Chen, Shouqian; Xiao, Haosu; Fan, Zhigang

    2013-01-20

    A conformal dome was designed and the aberration characteristics of the dome were analyzed using Zernike aberration theory. By deriving the equation used to correct Zernike aberrations, the phase coefficients and the phase orders of diffractive optical elements (DOEs) used to correct primary Zernike aberrations were obtained. DOEs were simulated to correct the aberrations of the conformal dome by using optical design software, and the aberrations of the conformal dome decreased dramatically. Finally, a complete cooled conformal optical system was designed. The results show that the number of the fixed corrector's elements decreases by using DOEs, and the optical system has better imaging quality.

  11. Microelectromechanical mirrors and electrically-programmable diffraction gratings based on two-stage actuation

    DOEpatents

    Allen, James J.; Sinclair, Michael B.; Dohner, Jeffrey L.

    2005-11-22

    A microelectromechanical (MEM) device for redirecting incident light is disclosed. The MEM device utilizes a pair of electrostatic actuators formed one above the other from different stacked and interconnected layers of polysilicon to move or tilt an overlying light-reflective plate (i.e. a mirror) to provide a reflected component of the incident light which can be shifted in phase or propagation angle. The MEM device, which utilizes leveraged bending to provide a relatively-large vertical displacement up to several microns for the light-reflective plate, has applications for forming an electrically-programmable diffraction grating (i.e. a polychromator) or a micromirror array.

  12. Diffractive-optics-based beam combination of a phase-locked fiber laser array.

    PubMed

    Cheung, Eric C; Ho, James G; Goodno, Gregory D; Rice, Robert R; Rothenberg, Josh; Thielen, Peter; Weber, Mark; Wickham, Michael

    2008-02-15

    A diffractive optical element (DOE) is used as a beam combiner for an actively phase-locked array of fiber lasers. Use of a DOE eliminates the far-field sidelobes and the accompanying loss of beam quality typically observed in tiled coherent laser arrays. Using this technique, we demonstrated coherent combination of five fiber lasers with 91% efficiency and M2=1.04. Combination efficiency and phase locking is robust even with large amplitude and phase fluctuations on the input laser array elements. Calculations and power handling measurements suggest that this approach can scale to both high channel counts and high powers.

  13. A Three Dimensional Beam Profile Monitor Based on Residual Gas Ionization

    SciTech Connect

    Lewis, T.A.; Shapira, D.

    1998-11-04

    A three-dimensional beam profile monitor based on tracking the ionization of the residual gas molecules in the evacuated beam pipe is described. Tracking in position and time of the ions and electrons produced in the ionization enables simultaneous position sampling in three dimensions. Special features which make it possible to sample very low beam currents were employed.

  14. Analysis of oxytetracycline residue in salmon muscle using a portable analyzer based on Eu III luminescence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oxytetracycline (OTC), one of tetracycline (TC) antibiotics, is the most prominent therapeutant in aquaculture worldwide. In this work, OTC residue in salmon muscle is determined by europium-sensitized luminescence (ESL) using an LED-based portable analyzer. OTC is extracted in EDTA-McIlvaine buff...

  15. Isoelectric Point, Electric Charge, and Nomenclature of the Acid-Base Residues of Proteins

    ERIC Educational Resources Information Center

    Maldonado, Andres A.; Ribeiro, Joao M.; Sillero, Antonio

    2010-01-01

    The main object of this work is to present the pedagogical usefulness of the theoretical methods, developed in this laboratory, for the determination of the isoelectric point (pI) and the net electric charge of proteins together with some comments on the naming of the acid-base residues of proteins. (Contains 8 figures and 4 tables.)

  16. Post-extraction algal residue in steam-flaked corn-based diets for beef cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of post-extraction algal residue (PEAR) as N source 23 in steam-flaked corn-based (SFC) beef cattle finishing diets on intake, duodenal flow, digestion, ruminal microbial efficiency, ruminal parameters, and blood constituents were evaluated. Ruminally and duodenally cannulated steers (BW...

  17. Applicability of the Charm II system for monitoring antibiotic residues in manure-based composts.

    PubMed

    Kwon, S I; Owens, G; Ok, Y S; Lee, D B; Jeon, W-T; Kim, J G; Kim, K-R

    2011-01-01

    The effluence of veterinary antibiotics (VAs) to aquatic and terrestrial environments is of concern due to the potential adverse effects on human health, such as the production of antibiotic resistant bacteria. One of the main pathways for antibiotics to enter the environment is via the application of manure and/or manure-based composts as an alternative organic fertilizer to agricultural lands. While a wide diversity of manure-based composts are produced in Korea, there is currently no regulatory guideline for VA residues. Hence, monitoring and limiting the concentration of VA residues in manure and/or manure-based composts prior to application to the lands is important to mitigate any environmental burden. The current study was conducted to examine the applicability of the Charm II antibiotic test system for monitoring tetracyclines, sulfonamides and macrolides in manure-based composts. The Charm II system was a highly reproducible method for determining whether VA residue concentrations in manure-based compost exceeded specific guideline values. A wide range of manure-based composts and liquid fertilizers commercially available in Korea were examined using the Charm II system to monitor the residues of the target VAs. For this, the guideline concentrations of VA residues (0.8 mg kg(-1) for tetracyclines, 0.2 mg kg(-1) for sulfonamides, and 0.1 mg kg(-1) for macrolides) stated in 'Official Standard of Feeds' under the 'Control of Livestock and Fish Feed Act' in Korea were adopted to establish control points. Of the 70 compost samples examined 12 exceeded 0.8 mg kg(-1) for tetracyclines and 21 exceeded 0.2 mg kg(-1) for sulfonamides. Of the 25 liquid fertilizer samples examined most samples exceeded these prospective guidelines.

  18. Generalization of the residual cutting method based on the Krylov subspace

    NASA Astrophysics Data System (ADS)

    Abe, Toshihiko; Sekine, Yoshihito; Kikuchi, Kazuo

    2016-06-01

    The residual cutting (RC) method has been reported to have superior converging characteristics in numerically solving elliptic partial differential equations. However, its application is limited to linear problems with diagonal-dominant matrices in general, for which convergence of a relaxation method such as SOR is guaranteed. In this study, we propose the generalized residual cutting (GRC) method, which is based on the Krylov subspace and applicable to general unsymmetric linear problems. Also, we perform numerical experiments with various coefficient matrices, and show that the GRC method has some desirable properties such as convergence characteristics and memory usage, in comparison to the conventional RC, BiCGSTAB and GMRES methods.

  19. A microalgae residue based carbon solid acid catalyst for biodiesel production.

    PubMed

    Fu, Xiaobo; Li, Dianhong; Chen, Jie; Zhang, Yuanming; Huang, Weiya; Zhu, Yi; Yang, Jun; Zhang, Chengwu

    2013-10-01

    Biodiesel production from microalgae is recognized as one of the best solutions to deal with the energy crisis issues. However, after the oil extraction from the microalgae, the microalgae residue was generally discarded or burned. Here a novel carbon-based solid acid catalyst derived from microalgae residue by in situ hydrothermal partially carbonization were synthesized. The obtained catalyst was characterized and subjected to both the esterification of oleic acid and transesterification of triglyceride to produce biodiesel. The catalyst showed high catalytic activity and can be regenerated while its activity can be well maintained after five cycles.

  20. Multiobjective optimizations of a novel cryocooled dc gun based ultrafast electron diffraction beam line

    NASA Astrophysics Data System (ADS)

    Gulliford, Colwyn; Bartnik, Adam; Bazarov, Ivan

    2016-09-01

    We present the results of multiobjective genetic algorithm optimizations of a single-shot ultrafast electron diffraction beam line utilizing a 225 kV dc gun with a novel cryocooled photocathode system and buncher cavity. Optimizations of the transverse projected emittance as a function of bunch charge are presented and discussed in terms of the scaling laws derived in the charge saturation limit. Additionally, optimization of the transverse coherence length as a function of final rms bunch length at the sample location have been performed for three different sample radii: 50, 100, and 200 μ m , for two final bunch charges: 1 05 electrons (16 fC) and 1 06 electrons (160 fC). Example optimal solutions are analyzed, and the effects of disordered induced heating estimated. In particular, a relative coherence length of Lc ,x/σx=0.27 nm /μ m was obtained for a final bunch charge of 1 05 electrons and final bunch length of σt≈100 fs . For a final charge of 1 06 electrons the cryogun produces Lc ,x/σx≈0.1 nm /μ m for σt≈100 - 200 fs and σx≥50 μ m . These results demonstrate the viability of using genetic algorithms in the design and operation of ultrafast electron diffraction beam lines.

  1. Capacitive micromachined ultrasonic transducers with diffraction-based integrated optical displacement detection.

    PubMed

    Hall, Neal A; Lee, Wook; Degertekin, F Levent

    2003-11-01

    Capacitive detection limits the performance of capacitive micromachined ultrasonic transducers (CMUTs) by providing poor sensitivity below megahertz frequencies and limiting acoustic power output by imposing constraints on the membrane-substrate gap height. In this paper, an integrated optical interferometric detection method for CMUTs, which provides high displacement sensitivity independent of operation frequency and device capacitance, is reported. The method also enables optoelectronics integration in a small volume and provides optoelectronic isolation between transmit and receive electronics. Implementation of the method involves fabricating CMUTs on transparent substrates and shaping the electrode under each individual CMUT membrane in the form of an optical diffraction grating. Each CMUT membrane thus forms a phase-sensitive optical diffraction grating structure that is used to measure membrane displacements down to 2 x 10(-4) A/square root(Hz) level in the dc to 2-MHz range. Test devices are fabricated on quartz substrates, and ultrasonic array imaging in air is performed using a single 4-mm square CMUT consisting of 19 x 19 array of membranes operating at 750 kHz. PMID:14682641

  2. Physicochemical pretreatments and hydrolysis of furfural residues via carbon-based sulfonated solid acid.

    PubMed

    Ma, Bao Jun; Sun, Yuan; Lin, Ke Ying; Li, Bing; Liu, Wan Yi

    2014-03-01

    Potential commercial physicochemical pretreatment methods, NaOH/microwave and NaOH/ultrasound were developed, and the carbon-based sulfonated solid acid catalysts were prepared for furfural residues conversion into reducing sugars. After the two optimum pretreatments, both the content of cellulose increased (74.03%, 72.28%, respectively) and the content of hemicellulose (94.11%, 94.17% of removal rate, respectively) and lignin (91.75%, 92.09% of removal rate, respectively) decreased in furfural residues. The reducing sugar yields of furfural residues with the two physicochemical pretreatments on coal tar-based solid acid reached 33.94% and 33.13%, respectively, higher than that pretreated via NaOH alone (27%) and comparable to that pretreated via NaOH/H2O2 (35.67%). The XRD patterns, IR spectra and SEM images show microwave and ultrasound improve the pretreatment effect. The results demonstrate the carbon-based sulfonated solid acids and the physicochemical pretreatments are green, effective, low-cost for furfural residues conversion.

  3. Eddy Current Nondestructive Residual Stress Assessment in Shot-Peened Nickel-Base Superalloys

    NASA Astrophysics Data System (ADS)

    Blodgett, M. P.; Yu, F.; Nagy, P. B.

    2005-04-01

    Shot peening and other mechanical surface enhancement methods improve the fatigue resistance and foreign-object damage tolerance of metallic components by introducing beneficial near-surface compressive residual stresses and hardening the surface. However, the fatigue life improvement gained via surface enhancement is not explicitly accounted for in current engine component life prediction models because of the lack of accurate and reliable nondestructive methods that could verify the presence of compressive near-surface residual stresses in shot-peened hardware. In light of its frequency-dependent penetration depth, the measurement of eddy current conductivity has been suggested as a possible means to allow the nondestructive evaluation of subsurface residual stresses in surface-treated components. This technique is based on the so-called piezoresistivity effect, i.e., the stress-dependence of electrical resistivity. We found that, in contrast with most other materials, surface-treated nickel-base superalloys exhibit an apparent increase in electrical conductivity at increasing inspection frequencies, i.e., at decreasing penetration depths. Experimental results are presented to illustrate that the excess frequency-dependent apparent eddy current conductivity of shot-peened nickel-base superalloys can be used to estimate the absolute level and penetration depth of the compressive residual stress layer both before and after partial thermal relaxation.

  4. Colorful holographic display of 3D object based on scaled diffraction by using non-uniform fast Fourier transform

    NASA Astrophysics Data System (ADS)

    Chang, Chenliang; Xia, Jun; Lei, Wei

    2015-03-01

    We proposed a new method to calculate the color computer generated hologram of three-dimensional object in holographic display. The three-dimensional object is composed of several tilted planes which are tilted from the hologram. The diffraction from each tilted plane to the hologram plane is calculated based on the coordinate rotation in Fourier spectrum domains. We used the nonuniform fast Fourier transformation (NUFFT) to calculate the nonuniform sampled Fourier spectrum on the tilted plane after coordinate rotation. By using the NUFFT, the diffraction calculation from tilted plane to the hologram plane with variable sampling rates can be achieved, which overcomes the sampling restriction of FFT in the conventional angular spectrum based method. The holograms of red, green and blue component of the polygon-based object are calculated separately by using our NUFFT based method. Then the color hologram is synthesized by placing the red, green and blue component hologram in sequence. The chromatic aberration caused by the wavelength difference can be solved effectively by restricting the sampling rate of the object in the calculation of each wavelength component. The computer simulation shows the feasibility of our method in calculating the color hologram of polygon-based object. The 3D object can be displayed in color with adjustable size and no chromatic aberration in holographic display system, which can be considered as an important application in the colorful holographic three-dimensional display.

  5. Convergent Beam Electron Diffraction Study of Bi-BASED High Temperature Superconducting Layered Compounds

    NASA Astrophysics Data System (ADS)

    Zhang, X. F.; Yan, Y. F.; Fung, K. K.

    Cleaved specimens of layered compounds Bi2Sr2(CaCuO2)nCuO6, n = 0, 1 and 2 phases have been studied by convergent beam electron diffraction. The identity and the symmetry of the phases have been determined from the higher order Laue zone (HOLZ) rings and the symmetry of their [001] patterns. In the case of Bi2Sr2CuO6, the [001] axial periodicity corresponds to the component of the wave vector of the monoclinic modulation along the c axis. Widely different axial periodicities have been obtained. This is interpreted as the manifestation of the variation of the monoclinic modulation. The presence of basal stacking fault lowers the symmetry of the [001] pattern.

  6. Leaching of nitrogen and base cations from calcareous soil amended with organic residues.

    PubMed

    Zarabi, Mahboubeh; Jalali, Mohsen

    2012-01-01

    The potential for groundwater and surface water pollution by nutrients in organic residues, primarily nitrogen (N) and base cations (K+, Na+, Ca2+, Mg2+), is a consideration when applying such residues to land. In this study, we used a laboratory column leaching procedure to examine the leaching of N, K+, Na+, Ca2+ and Mg2+ in soils treated with two types of raw organic residues (poultry manure and potato residues) and one municipal waste compost, which are currently recycled on agricultural land in Iran. Each organic residue was thoroughly mixed with two different soils (sandy loam and clay) at the rate of 3%. Soil columns were leached at 4-d intervals for 92 d with distilled water, and effluents were analysed for pH, EC, nitrate (NO3(-)-N), ammonium (NH4(+)-N) K+, Na+, Ca2+ and Mg2+. The results indicated that the amounts of NO3(-)-N and NH4(+)-N leached from the poultry manure and potato residues could represent very important economic losses of N and pose an environmental threat under field conditions. The sandy loam soil amended with poultry manure lost the highest amount of NO3(-)-N (206.4 kg ha(-1)), and clay soil amended with poultry manure lost the highest amounts of NH4(+)-N (454.3 kg ha(-1)). The results showed that a treatment incorporating 3% of municipal waste compost could be used without negative effects to groundwater N concentration in clay soil. Significant amounts of K+, Na+, Ca2+, and Mg2+ were leached owing to the application of poultry manure, potato and municipal waste compost to soils. There was a positive relationship between K+, Na+, Ca2+, and Mg2+ with NO3(-)-N and NH4(+)-N leached in soils. Analysis of variance detected significant effects of amendment, soil type and time on the leaching NO3(-)-N, NH4(+)-N, K+, Na+, Ca2+ and Mg2+.

  7. Determination of liquid's molecular interference function based on X-ray diffraction and dual-energy CT in security screening.

    PubMed

    Zhang, Li; YangDai, Tianyi

    2016-08-01

    A method for deriving the molecular interference function (MIF) of an unknown liquid for security screening is presented. Based on the effective atomic number reconstructed from dual-energy computed tomography (CT), equivalent molecular formula of the liquid is estimated. After a series of optimizations, the MIF and a new effective atomic number are finally obtained from the X-ray diffraction (XRD) profile. The proposed method generates more accurate results with less sensitivity to the noise and data deficiency of the XRD profile. PMID:27239986

  8. Exploring hardness enhancement in superhard tungsten tetraboride-based solid solutions using radial X-ray diffraction

    SciTech Connect

    Xie, Miao; Turner, Christopher L.; Mohammadi, Reza; Kaner, Richard B. E-mail: akavner@ucla.edu Tolbert, Sarah H. E-mail: akavner@ucla.edu; Kavner, Abby E-mail: akavner@ucla.edu

    2015-07-27

    In this work, we explore the hardening mechanisms in WB{sub 4}-based solid solutions upon addition of Ta, Mn, and Cr using in situ radial X-ray diffraction techniques under non-hydrostatic pressure. By examining the lattice-supported differential strain, we provide insights into the mechanism for hardness increase in binary solid solutions at low dopant concentrations. Speculations on the combined effects of electronic structure and atomic size in ternary WB{sub 4} solid solutions containing Ta with Mn or Cr are also included to understand the extremely high hardness of these materials.

  9. Measurement of yarn twist based on backward light scattering and small-angle far-field diffraction

    NASA Astrophysics Data System (ADS)

    Pei, Z. G.; Tao, X. M.

    2015-12-01

    This paper presents a non-destructive, non-contact method for measuring the twist of a yarn based on light scattering and diffraction. The surface twist angle is measured by determining the direction of the line with the highest intensity on the backward light scattering pattern which is perpendicular to the surface fibers, which is verified by both theoretical analysis based on Beckmann’s scattering model and experiments. The yarn diameter is measured with good accuracy by using the small-angle far-field diffraction pattern of the yarn body. Yarn twist is then derived from the measured surface twist angle and yarn diameter. Further studies reveal that the measured yarn twists by the proposed method are comparable to those measured based on microscopic images of the yarn. This method requires no high-magnification optics and is able to pick up short-term variations of twist with less labor intensity, indicating its potential application in the on-line measuring of yarn twist and its distribution.

  10. Residue-Level Prediction of HIV-1 Antibody Epitopes Based on Neutralization of Diverse Viral Strains

    PubMed Central

    Chuang, Gwo-Yu; Acharya, Priyamvada; Schmidt, Stephen D.; Yang, Yongping; Louder, Mark K.; Zhou, Tongqing; Kwon, Young Do; Pancera, Marie; Bailer, Robert T.; Doria-Rose, Nicole A.; Nussenzweig, Michel C.; Mascola, John R.; Kwong, Peter D.

    2013-01-01

    Delineation of antibody epitopes at the residue level is key to understanding antigen resistance mutations, designing epitope-specific probes for antibody isolation, and developing epitope-based vaccines. Ideally, epitope residues are determined in the context of the atomic-level structure of the antibody-antigen complex, though structure determination may in many cases be impractical. Here we describe an efficient computational method to predict antibody-specific HIV-1 envelope (Env) epitopes at the residue level, based on neutralization panels of diverse viral strains. The method primarily utilizes neutralization potency data over a set of diverse viral strains representing the antigen, and enhanced accuracy could be achieved by incorporating information from the unbound structure of the antigen. The method was evaluated on 19 HIV-1 Env antibodies with neutralization panels comprising 181 diverse viral strains and with available antibody-antigen complex structures. Prediction accuracy was shown to improve significantly over random selection, with an average of greater-than-8-fold enrichment of true positives at the 0.05 false-positive rate level. The method was used to prospectively predict epitope residues for two HIV-1 antibodies, 8ANC131 and 8ANC195, for which we experimentally validated the predictions. The method is inherently applicable to antigens that exhibit sequence diversity, and its accuracy was found to correlate inversely with sequence conservation of the epitope. Together the results show how knowledge inherent to a neutralization panel and unbound antigen structure can be utilized for residue-level prediction of antibody epitopes. PMID:23843642

  11. Recent diffractive results from HERA

    NASA Astrophysics Data System (ADS)

    Valkárová, Alice

    2016-07-01

    The diffractive dijet cross sections for photoproduction and deep inelastic scattering were studied and compared with theoretical NLO QCD predictions. The results of exclusive dijet production were compared to predictions from models which are based on different assumptions about the nature of diffractive exchange. Isolated prompt photons in diffractive photoproduction produced inclusively or together with a jet were studied for the first time.

  12. Optimal path choice in railway passenger travel network based on residual train capacity.

    PubMed

    Dou, Fei; Yan, Kai; Huang, Yakun; Wang, Li; Jia, Limin

    2014-01-01

    Passenger's optimal path choice is one of the prominent research topics in the field of railway passenger transport organization. More and more different train types are available, increasing path choices from departure to destination for travelers are unstoppable. However, travelers cannot avoid being confused when they hope to choose a perfect travel plan based on various travel time and cost constraints before departure. In this study, railway passenger travel network is constructed based on train timetable. Both the generalized cost function we developed and the residual train capacity are considered to be the foundation of path searching procedure. The railway passenger travel network topology is analyzed based on residual train capacity. Considering the total travel time, the total travel cost, and the total number of passengers, we propose an optimal path searching algorithm based on residual train capacity in railway passenger travel network. Finally, the rationale of the railway passenger travel network and the optimal path generation algorithm are verified positively by case study.

  13. Optimal Path Choice in Railway Passenger Travel Network Based on Residual Train Capacity

    PubMed Central

    Dou, Fei; Yan, Kai; Huang, Yakun; Jia, Limin

    2014-01-01

    Passenger's optimal path choice is one of the prominent research topics in the field of railway passenger transport organization. More and more different train types are available, increasing path choices from departure to destination for travelers are unstoppable. However, travelers cannot avoid being confused when they hope to choose a perfect travel plan based on various travel time and cost constraints before departure. In this study, railway passenger travel network is constructed based on train timetable. Both the generalized cost function we developed and the residual train capacity are considered to be the foundation of path searching procedure. The railway passenger travel network topology is analyzed based on residual train capacity. Considering the total travel time, the total travel cost, and the total number of passengers, we propose an optimal path searching algorithm based on residual train capacity in railway passenger travel network. Finally, the rationale of the railway passenger travel network and the optimal path generation algorithm are verified positively by case study. PMID:25097867

  14. Diffraction-based sensitivity analysis for an external occulter laboratory demonstration.

    PubMed

    Sirbu, Dan; Kim, Yunjong; Jeremy Kasdin, N; Vanderbei, Robert J

    2016-08-01

    An external flower-shaped occulter flying in formation with a space telescope can theoretically provide sufficient starlight suppression to enable direct imaging of an Earth-like planet. Occulter shapes are scaled to enable experimental validation of their performance at laboratory dimensions. Previous experimental results have shown promising performance but have not realized the full theoretical potential of occulter designs. Here, we develop a two-dimensional diffraction model for optical propagations for occulters incorporating experimental errors. We perform a sensitivity analysis, and comparison with experimental results from a scaled-occulter testbed validates the optical model to the 10-10 contrast level. The manufacturing accuracy along the edge of the occulter shape is identified as the limiting factor to achieving the theoretical potential of the occulter design. This hypothesis is experimentally validated using a second occulter mask manufactured with increased edge feature accuracy and resulting in a measured contrast level approaching the 10-12 level-a better than one order of magnitude improvement in performance. PMID:27505392

  15. Determining the Structure of Biomaterials Interfaces using Synchrotron-based X-ray Diffraction

    SciTech Connect

    McBride, M

    2002-01-24

    The purpose of this project is to explore the feasibility of using surface X-ray diffraction (SXRD) to determine the structure of biomineral surfaces in electrolyte solutions and of the adsorbed layer of acidic amino acids that are believed to play a central role in the control of biomineral formation and function. The work is a critical component in the development of an integrated picture of the physical and chemical basis for deposition and dissolution at solid-liquid interfaces in biological systems, and brings a new and very powerful surface-sensitive capability to LLNL. We have chosen as our model systems calcium carbonate and calcium phosphate in aspartic and glutamic acid-bearing solutions. The calcium compounds are ubiquitous among biomineral structures, both those that are beneficial such as bones and teeth, and those that are pathological such as kidney stones, while the two acidic amino acids--both as simple and poly-amino acids--are the dominant constituents of protein mixtures implicated in the control of biomineralization. The goals of the work are: (1) to determine the surface structure of pure calcium phosphate and calcium carbonate surfaces in aqueous solution using SXRD; (2) to determine how those surfaces are modified by the presence of aspartic and glutamic acid, both as the simple amino acids and as poly-aspartate and poly-glutamate and (3) to model the interactions of acidic amino acids with calcite.

  16. A novel device based on a fluorescent cross-responsive sensor array for detecting pesticide residue

    NASA Astrophysics Data System (ADS)

    Huang, Jing; Hou, Changjun; Lei, Jincan; Huo, Danqun; Luo, Xiaogang; Dong, Liang

    2016-11-01

    In this paper, a novel, simple, rapid, and low-cost detection device for pesticide residue was constructed. A sensor array based on a cross-responsive mechanism was designed. The data collection and processing system was used to detect fluorescent signal of the sensor arrays, and to extract unique patterns of the tested pesticide residue. Four selected pesticides, carbendazim, diazine, fenvalerate, and pentachloronitrobenzene, were detected by the proposed device. Unsupervised pattern recognition methods, hierarchical cluster analysis and principal component analysis, were used to analyze the data. The results showed that the methods could 100% discriminate the four pesticide residues. According to the standard regression linear curve of the fluorescence intensity and the concentration of pesticide, the quantitative value of the pesticide was detected, and the device obtained responses at concentrations below 8 ppb, and it has a good linear relationship in the range of 0.01-1 ppm. According to the results, the proposed detection device showed excellent selectivity and discrimination ability for the pesticide residues. However, our preliminary study demonstrated that the proposed detection device has excellent potential application for the safety inspection of food.

  17. Two States Mapping Based Time Series Neural Network Model for Compensation Prediction Residual Error

    NASA Astrophysics Data System (ADS)

    Jung, Insung; Koo, Lockjo; Wang, Gi-Nam

    2008-11-01

    The objective of this paper was to design a model of human bio signal data prediction system for decreasing of prediction error using two states mapping based time series neural network BP (back-propagation) model. Normally, a lot of the industry has been applied neural network model by training them in a supervised manner with the error back-propagation algorithm for time series prediction systems. However, it still has got a residual error between real value and prediction result. Therefore, we designed two states of neural network model for compensation residual error which is possible to use in the prevention of sudden death and metabolic syndrome disease such as hypertension disease and obesity. We determined that most of the simulation cases were satisfied by the two states mapping based time series prediction model. In particular, small sample size of times series were more accurate than the standard MLP model.

  18. Visual Analysis of Residuals from Data-Based Models in Complex Industrial Processes

    NASA Astrophysics Data System (ADS)

    Ordoñez, Daniel G.; Cuadrado, Abel A.; Díaz, Ignacio; García, Francisco J.; Díez, Alberto B.; Fuertes, Juan J.

    2012-10-01

    The use of data-based models for visualization purposes in an industrial background is discussed. Results using Self-Organizing Maps (SOM) show how through a good design of the model and a proper visualization of the residuals generated by the model itself, the behavior of essential parameters of the process can be easily tracked in a visual way. Real data from a cold rolling facility have been used to prove the advantages of these techniques.

  19. Local x-ray diffraction analysis of the structure of dendrites in single-crystal nickel-base superalloys

    SciTech Connect

    Brueckner, U.; Epishin, A.; Link, T.

    1997-12-01

    The structure of the dendrites in the single-crystal nickel-base superalloys SC16, SRR99 and CMSX4 with different refractory element levels (Mo + Ta + W + Re) has been investigated by local X-ray diffraction. A special technique was used to improve the spatial resolution of the X-ray diffraction and to enable the precise control of the X-ray spot position within the dendritic structure. A significant change of the {gamma}/{gamma}{prime}-lattice misfit was found within the dendrite in the superalloys with higher refractory element levels SRR99 and CMSX4. The observed misfit change is based on the change of the {gamma}-lattice parameter due to segregation of W and Re. The intensity of the X-ray beam reflected from the dendrite periphery was found to be weaker than that from the dendrite centre because of the mosaicity. Therefore misfit measurements without knowledge of the X-ray spot position in the dendritic structure lead to values that correspond more to the dendrite core.

  20. UV-laser-based longitudinal illuminated diffuser (LID) incorporating diffractive and Lambertian reflectance for the disinfection of beverages

    NASA Astrophysics Data System (ADS)

    Lizotte, Todd

    2010-08-01

    A novel laser beam shaping system was designed to demonstrate the potential of using high power UV laser sources for large scale disinfection of liquids used in the production of food products, such as juices, beer, milk and other beverage types. The design incorporates a patented assembly of optical components including a diffractive beam splitting/shaping element and a faceted pyramidal or conically shaped Lambertian diffuser made from a compression molded PTFE compounds. When properly sintered to an appropriate density, as an example between 1.10 and 1.40 grams per cubic centimeter, the compressed PTFE compounds show a ~99% reflectance at wavelengths ranging from 300 nm to 1500 nm, and a ~98.5% refection of wavelengths from 250 nm to 2000 nm [1]. The unique diffuser configuration also benefits from the fact that the PTFE compounds do not degrade when exposed to ultraviolet radiation as do barium sulfate materials and silver or aluminized mirror coatings [2]. These components are contained within a hermetically sealed quartz tube. Once assembled a laser beam is directed through one end of the tube. This window takes the form of a computer generated diffractive splitter or other diffractive shaper element to split the laser beam into a series of spot beamlets, circular rings or other geometric shapes. As each of the split beamlets or rings cascade downward, they illuminate various points along the tapered PTFE cone or faceted pyramidal form. As they strike the surface they each diffuse in a Lambertian reflectance pattern creating a pseudo-uniform circumferential illuminator along the length of the quartz tube enclosing the assembly. The compact tubular structure termed Longitudinal Illuminated Diffuser (LID) provides a unique UV disinfection source that can be placed within a centrifugal reactor or a pipe based reactor chamber. This paper will review the overall design principle, key component design parameters, preliminary analytic and bench operational testing

  1. Diffractive-optics-based sensor as a tool for detection of biocompatibility of titanium and titanium-doped hydrocarbon samples.

    PubMed

    Silvennoinen, Raimo; Hasoň, Stanislav; Vetterl, Vladimír; Penttinen, Niko; Silvennoinen, Martti; Myller, Kari; Cernochová, Pavlína; Bartáková, Sonia; Prachár, Patrik; Cvrček, Ladislav

    2010-10-10

    Adsorption of the elongated human plasma fibrinogen (HPF) and globular human serum albumin molecules on a titanium-based surface is monitored by analyzing permittivity and optical roughness of protein-modified surfaces by using a diffractive optical element (DOE)-based sensor and variable angle spectro-ellipsometry (VASE). Both DOE and VASE confirmed that fibrinogen forms a thicker and more packed surface adlayer compared to a more porous and weakly adsorbed albumin adlayer. A linear relation of the permittivity (ε(')) and dielectric loss (ε('')) was found for some of the dry titanium-doped hydrocarbon (TDHC) surfaces with excellent HPF adsorption ability. We discuss some aspects of TDHC's aging and its possible effects on fibrinogen adsorption.

  2. A new 3D shape precision measurement system calibration method based on non-diffraction grating structured light projection

    NASA Astrophysics Data System (ADS)

    Zhu, Ya; Zhou, Liping; Li, Wenlong; Gan, Jianghong; Xu, Long

    2016-03-01

    Phase calculation-based fringe projection techniques are widely used in three-dimensional shape measurement fields to obtain the 3D shape data of the object's surface. One important step of the phase calculation is calibration, which determines the relationship between the image phase and depth information. The traditional calibration methods are too complex and require many parameters. In this paper, model of 3D shape precision calibration method based on non-diffraction grating structured light fringes projection is proposed, which is consist of camera model, fringe phase obtaining, height-phase relationship model. This method is simple, convenient and there is no approximation in it, which can satisfy the precision measurement.

  3. A grating-based single-shot x-ray phase contrast and diffraction method for in vivo imaging

    SciTech Connect

    Bennett, Eric E.; Kopace, Rael; Stein, Ashley F.; Wen Han

    2010-11-15

    Purpose: The purpose of this study is to develop a single-shot version of the grating-based phase contrast x-ray imaging method and demonstrate its capability of in vivo animal imaging. Here, the authors describe the principle and experimental results. They show the source of artifacts in the phase contrast signal and optimal designs that minimize them. They also discuss its current limitations and ways to overcome them. Methods: A single lead grid was inserted midway between an x-ray tube and an x-ray camera in the planar radiography setting. The grid acted as a transmission grating and cast periodic dark fringes on the camera. The camera had sufficient spatial resolution to resolve the fringes. Refraction and diffraction in the imaged object manifested as position shifts and amplitude attenuation of the fringes, respectively. In order to quantify these changes precisely without imposing a fixed geometric relationship between the camera pixel array and the fringes, a spatial harmonic method in the Fourier domain was developed. The level of the differential phase (refraction) contrast as a function of hardware specifications and device geometry was derived and used to guide the optimal placement of the grid and object. Both ex vivo and in vivo images of rodent extremities were collected to demonstrate the capability of the method. The exposure time using a 50 W tube was 28 s. Results: Differential phase contrast images of glass beads acquired at various grid and object positions confirmed theoretical predictions of how phase contrast and extraneous artifacts vary with the device geometry. In anesthetized rats, a single exposure yielded artifact-free images of absorption, differential phase contrast, and diffraction. Differential phase contrast was strongest at bone-soft tissue interfaces, while diffraction was strongest in bone. Conclusions: The spatial harmonic method allowed us to obtain absorption, differential phase contrast, and diffraction images, all from a

  4. Highly sensitive homogeneous electrochemical aptasensor for antibiotic residues detection based on dual recycling amplification strategy.

    PubMed

    Wang, Xiuzhong; Dong, Shanshan; Gai, Panpan; Duan, Rui; Li, Feng

    2016-08-15

    The ubiquitous presence of antibiotic residues in foodstuff have serious health consequences for consumers from allergic reactions to the evolution of antibiotic-resistant bacteria. To address this problem, a novel homogeneous electrochemical aptasensor with high sensitivity and specificity is designed for antibiotic residues detection based on target-induced and T7 exonuclease-assisted dual recycling signal amplification strategy. It was realized by the remarkable diffusivity difference between hairpin probe and the mononucleotides towards the negatively charged indium tin oxide electrode. For the proof-of-concept experiment, ampicillin, was employed as a model analyte to examine the desirable properties of this assay. A low detection limit of 4.0pM toward ampicillin with an excellent selectivity could be achieved, which has been successfully applied to assay antibiotic in milk. What's more, compared with the immobilization-based electrochemical means, the proposed sensing system avoids the tedious and time-consuming steps of electrode modification, making the experimental processes much simpler and more convenient. With the advantages of high sensitivity, excellent selectivity and simple operation, it is believed that this strategy possesses great potential for the simple, easy and convenient detection of antibiotic residues in food safety field.

  5. Generalization of the residual cutting method based on the Krylov subspace

    NASA Astrophysics Data System (ADS)

    Abe, Toshihiko; Sekine, Yoshihito; Kikuchi, Kazuo

    2016-06-01

    The residual cutting (RC) method has been reported to have superior converging characteristics in numerically solving elliptic partial differential equations. However, its application is limited to linear problems with diagonal-dominant matrices in general, for which convergence of a relaxation method such as SOR is guaranteed. In this study, we propose the generalized residual cutting (GRC) method, which is based on the Krylov subspace and applicable to general unsymmetric linear problems. Also, we perform numerical experiments with various coefficient matrices, and show that the GRC method has some desirable properties such as convergence characteristics and memory usage, in comparison to the conventional RC, BiCGSTAB and GMRES methods. At the request of the author of this paper, a corrigendum was issued on 22 June 2016 to correct an error in Eq. (2) and Eq. (3).

  6. Rapid detection of pesticide residue in apple based on Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Li, Yongyu; Sun, Yunyun; Peng, Yankun; Dhakal, Sagar; Chao, Kuanglin; Liu, Qiaoqiao

    2012-05-01

    The potential of Raman spectroscopy in the analysis of low concentration organic contaminants on apples' surface was evidenced in this study. Chlorpyrifos, an organophosphorus pesticide, was used as a probe for this purpose. The characteristic peaks of fingerprints of pesticide on an aluminum substrate and apple fruit cuticle without pesticide residue were acquired first. Then a concentration range of chlorpyrifos (commercial products at 40%) solutions were made using deionised and distilled water. Single 100 μL droplets of the chlorpyrifos solutions were placed gently on apple fruit cuticles and left to dry before analysis. Through comparative analysis of the Raman spectra data collected, 341, 632 and 1237cm-1 were identified to detect the chlorpyrifos pesticide residue on apple surface. Based on the relationship between the Raman intensity of the most prominent peak at around 632cm-1 and the pesticide concentrations, the limit of detection of ordinary Raman spectrum for chlorpyrifos was estimated to be 48ppm.

  7. Using the model-based residual bootstrap to quantify uncertainty in fiber orientations from Q-ball analysis.

    PubMed

    Haroon, Hamied A; Morris, David M; Embleton, Karl V; Alexander, Daniel C; Parker, Geoffrey J M

    2009-04-01

    Bootstrapping of repeated diffusion-weighted image datasets enables nonparametric quantification of the uncertainty in the inferred fiber orientation. The wild bootstrap and the residual bootstrap are model-based residual resampling methods which use a single dataset. Previously, the wild bootstrap method has been presented as an alternative to conventional bootstrapping for diffusion tensor imaging. Here we present a study of an implementation of model-based residual bootstrapping using q -ball analysis and compare the outputs with conventional bootstrapping. We show that model-based residual bootstrap q-ball generates results that closely match the output of the conventional bootstrap. Both the residual and conventional bootstrap of multifiber methods can be used to estimate the probability of different numbers of fiber populations existing in different brain tissues. Also, we have shown that these methods can be used to provide input for probabilistic tractography, avoiding existing limitations associated with data calibration and model selection.

  8. Formulation and characterization of functional foods based on fruit and vegetable residue flour.

    PubMed

    Ferreira, Mariana S L; Santos, Mônica C P; Moro, Thaísa M A; Basto, Gabriela J; Andrade, Roberta M S; Gonçalves, Édira C B A

    2015-02-01

    Fruits and vegetables are extensively processed and the residues are often discarded. However, due to their rich composition, they could be used to minimize food waste. This study aimed to develop food products based on the solid residue generated from the manufacture of an isotonic beverage. This beverage was produced based on integral exploitation of several fruits and vegetables: orange, passion fruit, watermelon, lettuce, courgette, carrot, spinach, mint, taro, cucumber and rocket. The remaining residue was processed into flour and its functional properties were evaluated. The fruit and vegetable residue (FVR) flour was incorporated with different levels (20 to 35 %) into biscuits and cereal bars. The proximate composition, microbiological stability until 90 days and consumer acceptance were analyzed. The FVR flour presented a higher water holding capacity than oil holding capacity, respectively 7.43 and 1.91 g g(-1) of flour, probably associated with its high levels of carbohydrates (53 %) and fibres (21.5 %). Biscuits enriched with 35 % of FVR flour presented significantly higher fibre, ranging from 57 % to 118 % and mineral contents, from 25 % to 37 % than when only 20 % was added. Cereal bars presented about 75 % of fibres and variable mineral contents between 14 % and 37 %. The incorporation of FVR did not change the fat content. The microbiological examinations are within acceptable limits according to international regulation. The incorporation of FVR flour did not impair consumer acceptance, the sensory attributes averaged around 6. The chemical, microbiological and sensorial results of the designed products attested for an alternative towards applying and reducing agro-industrial wastes. PMID:25694690

  9. Formulation and characterization of functional foods based on fruit and vegetable residue flour.

    PubMed

    Ferreira, Mariana S L; Santos, Mônica C P; Moro, Thaísa M A; Basto, Gabriela J; Andrade, Roberta M S; Gonçalves, Édira C B A

    2015-02-01

    Fruits and vegetables are extensively processed and the residues are often discarded. However, due to their rich composition, they could be used to minimize food waste. This study aimed to develop food products based on the solid residue generated from the manufacture of an isotonic beverage. This beverage was produced based on integral exploitation of several fruits and vegetables: orange, passion fruit, watermelon, lettuce, courgette, carrot, spinach, mint, taro, cucumber and rocket. The remaining residue was processed into flour and its functional properties were evaluated. The fruit and vegetable residue (FVR) flour was incorporated with different levels (20 to 35 %) into biscuits and cereal bars. The proximate composition, microbiological stability until 90 days and consumer acceptance were analyzed. The FVR flour presented a higher water holding capacity than oil holding capacity, respectively 7.43 and 1.91 g g(-1) of flour, probably associated with its high levels of carbohydrates (53 %) and fibres (21.5 %). Biscuits enriched with 35 % of FVR flour presented significantly higher fibre, ranging from 57 % to 118 % and mineral contents, from 25 % to 37 % than when only 20 % was added. Cereal bars presented about 75 % of fibres and variable mineral contents between 14 % and 37 %. The incorporation of FVR did not change the fat content. The microbiological examinations are within acceptable limits according to international regulation. The incorporation of FVR flour did not impair consumer acceptance, the sensory attributes averaged around 6. The chemical, microbiological and sensorial results of the designed products attested for an alternative towards applying and reducing agro-industrial wastes.

  10. Statistical Reliability of Phase Fraction Determination Based on Electron Backscatter Diffraction (EBSD) Investigations on the Example of an Al-TRIP Steel

    NASA Astrophysics Data System (ADS)

    Davut, Kemal; Zaefferer, Stefan

    2010-09-01

    The aim of this article is to discuss the representativeness of electron backscatter diffraction (EBSD) mapping data for phase fraction determination in multiphase materials. Particular attention is paid to the effect of step size and scanned area. The experimental investigations were carried out on a low-alloyed steel with transformation induced plasticity (TRIP) that shows a relatively heterogeneous distribution of residual austenite in a ferrite matrix. EBSD scans of various area sizes and step sizes were carried out and analyzed with respect to the determined austenite phase fraction. The step size has only an indirect influence on the results, as it determines the size of the investigated area if the number of measurement points is kept constant. Based on the experimental results, the optimum sampling conditions in terms of analyzed area size and the number of measurement points were determined. These values were compared with values obtained from Cochran’s formula, which allows calculation of sampling sizes for predefined levels of precision and confidence. A significant deviation of experimental from theoretical optimum sample sizes was found. This deviation is, for the most part, a result of the heterogeneous distribution of the austenite phase. Depending on grain size and volume fraction of the second phase, the false assignment of phases at grain boundaries also may introduce a significant error. A general formula is introduced that allows estimation of the error caused by these parameters. Finally, a new measurement scheme is proposed that allows improvement of reliability and representativeness of EBSD-based phase determination without large sacrifices in measurement time or data set sizes.

  11. Release time of residual oxygen after dental bleaching with 35% hydrogen peroxide: effect of a catalase-based neutralizing agent.

    PubMed

    Guasso, Bárbara; Salomone, Paloma; Nascimento, Paulo Cícero; Pozzobon, Roselaine Terezinha

    2016-01-01

    This article assessed the effect of a catalase-based agent on residual oxygen (O2) release from teeth exposed to 35% hydrogen peroxide (H2O2). The use of the catalase-based neutralizer agent for 2-3 minutes was able to release residual O2 5 days after exposure to a 35% H2O2-based bleaching gel. PMID:27148658

  12. Multicomponent mesofluidic system for the detection of veterinary drug residues based on competitive immunoassay.

    PubMed

    Hu, Lei; Zuo, Peng; Ye, Bang-Ce

    2010-10-01

    An automated multicomponent mesofluidic system (MCMS) based on biorecognitions carried out on meso-scale glass beads in polydimethylsiloxane (PDMS) channels was developed. The constructed MCMS consisted of five modules: a bead introduction module, a bioreaction module, a solution handling module, a liquid driving module, and a signal collection module. The integration of these modules enables the assay to be automated and reduces it to a one-step protocol. The MCMS has successfully been applied toward the detection of veterinary drug residues in animal-derived foods. The drug antigen-coated beads (varphi250 microm) were arrayed in the PDMS channels (varphi300 microm). The competitive immunoassay was then carried out on the surface of the glass beads. After washing, the Cy3-labeled secondary antibody was introduced to probe the antigen-antibody complex anchored to the beads. The fluorescence intensity of each bead was measured and used to determine the residual drug concentration. The MCMS is highly sensitive, with its detection limits ranging from 0.02 (salbutamol) to 3.5 microg/L (sulfamethazine), and has a short assay time of 45 min or less. The experimental results demonstrate that the MCMS proves to be an economic, efficient, and sensitive platform for multicomponent detection of compound residues for contamination in foods or the environment.

  13. A C. elegans-based foam for rapid on-site detection of residual live virus.

    SciTech Connect

    Negrete, Oscar A.; Branda, Catherine; Hardesty, Jasper O. E.; Tucker, Mark David; Kaiser, Julia N.; Kozina, Carol L.; Chirica, Gabriela S.

    2012-02-01

    In the response to and recovery from a critical homeland security event involving deliberate or accidental release of biological agents, initial decontamination efforts are necessarily followed by tests for the presence of residual live virus or bacteria. Such 'clearance sampling' should be rapid and accurate, to inform decision makers as they take appropriate action to ensure the safety of the public and of operational personnel. However, the current protocol for clearance sampling is extremely time-intensive and costly, and requires significant amounts of laboratory space and capacity. Detection of residual live virus is particularly problematic and time-consuming, as it requires evaluation of replication potential within a eukaryotic host such as chicken embryos. The intention of this project was to develop a new method for clearance sampling, by leveraging Sandia's expertise in the biological and material sciences in order to create a C. elegans-based foam that could be applied directly to the entire contaminated area for quick and accurate detection of any and all residual live virus by means of a fluorescent signal. Such a novel technology for rapid, on-site detection of live virus would greatly interest the DHS, DoD, and EPA, and hold broad commercial potential, especially with regard to the transportation industry.

  14. DDT-based indoor residual spraying suboptimal for visceral leishmaniasis elimination in India.

    PubMed

    Coleman, Michael; Foster, Geraldine M; Deb, Rinki; Pratap Singh, Rudra; Ismail, Hanafy M; Shivam, Pushkar; Ghosh, Ayan Kumar; Dunkley, Sophie; Kumar, Vijay; Coleman, Marlize; Hemingway, Janet; Paine, Mark J I; Das, Pradeep

    2015-07-14

    Indoor residual spraying (IRS) is used to control visceral leishmaniasis (VL) in India, but it is poorly quality assured. Quality assurance was performed in eight VL endemic districts in Bihar State, India, in 2014. Residual dichlorodiphenyltrichloroethane (DDT) was sampled from walls using Bostik tape discs, and DDT concentrations [grams of active ingredient per square meter (g ai/m(2))] were determined using HPLC. Pre-IRS surveys were performed in three districts, and post-IRS surveys were performed in eight districts. A 20% threshold above and below the target spray of 1.0 g ai/m(2) was defined as "in range." The entomological assessments were made in four districts in IRS and non-IRS villages. Vector densities were measured: pre-IRS and 1 and 3 mo post-IRS. Insecticide susceptibility to 4% DDT and 0.05% deltamethrin WHO-impregnated papers was determined with wild-caught sand flies. The majority (329 of 360, 91.3%) of pre-IRS samples had residual DDT concentrations of <0.1 g ai/m(2). The mean residual concentration of DDT post-IRS was 0.37 g ai/m(2); 84.9% of walls were undersprayed, 7.4% were sprayed in range, and 7.6% were oversprayed. The abundance of sand flies in IRS and non-IRS villages was significantly different at 1 mo post-IRS only. Sand flies were highly resistant to DDT but susceptible to deltamethrin. The Stockholm Convention, ratified by India in 2006, calls for the complete phasing out of DDT as soon as practical, with limited use in the interim where no viable IRS alternatives exist. Given the poor quality of the DDT-based IRS, ready availability of pyrethroids, and susceptibility profile of Indian sand flies, the continued use of DDT in this IRS program is questionable.

  15. Bayesian-based aberration correction and numerical diffraction for improved lensfree on-chip microscopy of biological specimens.

    PubMed

    Wong, Alexander; Kazemzadeh, Farnoud; Jin, Chao; Wang, Xiao Yu

    2015-05-15

    Lensfree on-chip microscopy is an emerging imaging technique that can be used to visualize and study biological specimens without the need for imaging lens systems. Important issues that can limit the performance of lensfree on-chip microscopy include interferometric aberrations, acquisition noise, and image reconstruction artifacts. In this study, we introduce a Bayesian-based method for performing aberration correction and numerical diffraction that accounts for all three of these issues to improve the effective numerical aperture (NA) and signal-to-noise ratio (SNR) of the reconstructed microscopic image. The proposed method was experimentally validated using the USAF resolution target as well as real waterborne Anabaena flos-aquae samples, demonstrating improvements in NA by ∼25% over the standard method, and improvements in SNR of 2.8 and 8.2 dB in the reconstructed image when compared to the reconstructed images produced using the standard method and a maximum likelihood estimation method, respectively.

  16. Broadband 7-fs diffractive-optic-based 2D electronic spectroscopy using hollow-core fiber compression.

    PubMed

    Ma, Xiaonan; Dostál, Jakub; Brixner, Tobias

    2016-09-01

    We demonstrate noncollinear coherent two-dimensional (2D) electronic spectroscopy for which broadband pulses are generated in an argon-filled hollow-core fiber pumped by a 1-kHz Ti:Sapphire laser. Compression is achieved to 7 fs duration (TG-FROG) using dispersive mirrors. The hollow fiber provides a clean spatial profile and smooth spectral shape in the 500-700 nm region. The diffractive-optic-based design of the 2D spectrometer avoids directional filtering distortions and temporal broadening from time smearing. For demonstration we record data of cresyl-violet perchlorate in ethanol and use phasing to obtain broadband absorptive 2D spectra. The resulting quantum beating as a function of population time is consistent with literature data. PMID:27607681

  17. Experiment evaluation of speckle suppression efficiency of 2D quasi-spiral M-sequence-based diffractive optical element.

    PubMed

    Lapchuk, A; Pashkevich, G A; Prygun, O V; Yurlov, V; Borodin, Y; Kryuchyn, A; Korchovyi, A A; Shylo, S

    2015-10-01

    The quasi-spiral 2D diffractive optical element (DOE) based on M-sequence of length N=15 is designed and manufactured. The speckle suppression efficiency by the DOE rotation is measured. The speckle suppression coefficients of 10.5, 6, and 4 are obtained for green, violet, and red laser beams, respectively. The results of numerical simulation and experimental data show that the quasi-spiral binary DOE structure can be as effective in speckle reduction as a periodic 2D DOE structure. The numerical simulation and experimental results show that the speckle suppression efficiency of the 2D DOE structure decreases approximately twice at the boundaries of the visible range. It is shown that a replacement of this structure with the bilateral 1D DOE allows obtaining the maximum speckle suppression efficiency in the entire visible range of light. PMID:26479664

  18. A Multi-Anode Photomultiplier Tube Based Wavelength-Shifting-Fiber Detector for neutron diffraction

    SciTech Connect

    Berry, Kevin D; Clonts, Lloyd G; Crow, Lowell; Diawara, Yacouba; Funk, Loren L; Hannan, Bruce W; Hodges, Jason P; Riedel, Richard A; Wang, Cai-Lin

    2012-01-01

    The wavelength-shifting (WLS) fiber scintillator neutron detectors were developed for two time-of-flight (TOF) neutron powder diffractometers (POWGEN, VULCAN) at Spallation Neutron Source (SNS). In a recent module (v3.0), however, there are 32 1-inch-diameter photomultiplier tubes (PMTs) which are bulky and expensive. We built a new detector module (v3.1) based on four multi-anode (MA) PMTs, and tested its performance including detection efficiency, count rate capability, spatial resolution, ghosting properties, and gamma-ray sensitivity. The v3.1 module was compared with two prior v3.0 modules, and 3He tube detectors.

  19. Diffraction filters based on polyimide and poly(ethylene naphthalate) track membranes

    NASA Astrophysics Data System (ADS)

    Mitrofanov, A. V.; Apel, P. Yu.; Blonskaya, I. V.; Orelovitch, O. L.

    2006-09-01

    The problem of optical filters for soft x rays and extreme ultraviolet that provide a high degree of blocking ultraviolet and visible background radiations is considered. The subject of discussion is the filter based on a track membrane, a polymer film with micrometer and submicrometer pores, rather than the standard thin-film system. It is proposed that the membranes be made of poly(ethylene naphthalate) or polyimide, the UV absorption edge of which lies near the boundary of the visible range. The properties of poly(ethylene naphthalate) and polyimide membranes are contrasted with those of conventional porous poly(ethylene terephthalate) films, which are obtained by ion track etching. The spectral characteristics of poly(ethylene naphthalate) and polyimide films, as well as the formation of “track” pores when the specimens are successively treated by fast ions and chemicals, are studied. The basic parameters of the resulting porous structures are examined, and treatment conditions under which desired optical properties of the membranes are achieved are found. Filters based on poly(ethylene naphthalate) and polyimide track membranes may be applied in x-ray astronomy as constituents of detectors incorporated into solar telescopes and in experiments with the laboratory plasma.

  20. Titration of the bacteriorhodopsin Schiff base involves titration of an additional protein residue.

    PubMed

    Zadok, Uri; Asato, Alfred E; Sheves, Mordechai

    2005-06-14

    The retinal protein protonated Schiff base linkage plays a key role in the function of bacteriorhodopsin (bR) as a light-driven proton pump. In the unphotolyzed pigment, the Schiff base (SB) is titrated with a pK(a) of approximately 13, but following light absorption, it experiences a decrease in the pK(a) and undergoes several alterations, including a deprotonation process. We have studied the SB titration using retinal analogues which have intrinsically lower pK(a)'s which allow for SB titrations over a much lower pH range. We found that above pH 9 the channel for the SB titration is perturbed, and the titration rate is considerably reduced. On the basis of studies with several mutants, it is suggested that the protonation state of residue Glu204 is responsible for the channel perturbation. We suggest that above pH 12 a channel for the SB titration is restored probably due to titration of an additional protein residue. The observations may imply that during the bR photocycle and M photointermediate formation the rate of Schiff base protonation from the bulk is decreased. This rate decrease may be due to the deprotonation process of the "proton-releasing complex" which includes Glu204. In contrast, during the lifetime of the O intermediate, the protonated SB is exposed to the bulk. Possible implications for the switch mechanism, and the directionality of the proton movement, are discussed.

  1. Structural health monitoring system based on diffracted Lamb wave analysis by multiresolution processing

    NASA Astrophysics Data System (ADS)

    Lemistre, Michel; Balageas, Daniel

    2001-06-01

    A health monitoring system is presented composed of integrated disc-shaped, 100 µm thick and 5 mm diameter piezoelectric transducers (PZTs) working sequentially as Lamb wave emitters and receivers. The diagnostic is based on the analysis of Lamb wave signals recorded before and after damage. In the composite, delaminations are discontinuities producing mode conversion processes generating various outgoing modes. The multiresolution processing allows the isolation of various propagation modes and their extraction in order to measure, for various propagation paths, the time delay between the arrivals of the main burst and of a specific outgoing mode. This process permits, with good accuracy, the localization of damage and the estimation of its extent. The robustness and portability of this technique is demonstrated by the fact that, after validation in our laboratory, it was successfully applied to data coming from an experiment conducted in another laboratory using its own acousto-ultrasonic health monitoring hardware system.

  2. Active health system based on wavelet transform analysis of diffracted Lamb waves

    NASA Astrophysics Data System (ADS)

    Lemistre, Michel B.; Osmont, Daniel L.; Balageas, Daniel L.

    2000-08-01

    In composite materials, delaminations are discontinuities producing mode conversion processes generating various out-going modes. The Discrete Wavelet Transform allows isolating various propagation modes and extracting them in order to measure the time delay between the arrivals of the main burst and a specific out-going mode, for various propagation paths. This process permits, with a good accuracy, to localize a damage and to estimate its extension. An active health monitoring system composed of integrated disc-shaped, 100 (mu) m-thick and 5 mm-dia PZT transducers working sequentially as actuators and receives is presented. The diagnostic is based on multiresolution process by wavelet transform applied on recorded Lamb wave signals obtained before and after damage. The robustness and portability of this technique is demonstrated by the fact that, after validation in our laboratory it was successfully applied to data coming from an experiment conducted in an other Laboratory using its own Health Monitoring system.

  3. Solid state characterization and crystal structure from X-ray powder diffraction of two polymorphic forms of ranitidine base.

    PubMed

    de Armas, Héctor Novoa; Peeters, Oswald M; Blaton, Norbert; Van Gyseghem, Elke; Martens, Johan; Van Haele, Gerrit; Van Den Mooter, Guy

    2009-01-01

    Ranitidine hydrochloride (RAN-HCl), a known anti-ulcer drug, is the product of reaction between HCl and ranitidine base (RAN-B). RAN-HCl has been extensively studied; however this is not the case of the RAN-B. The solid state characterization of RAN-B polymorphs has been carried out using different analytical techniques (microscopy, thermal analysis, Fourier transform infrared spectrometry in the attenuated total reflection mode, (13)C-CPMAS-NMR spectroscopy and X-ray powder diffraction). The crystal structures of RAN-B form I and form II have been determined using conventional X-ray powder diffraction in combination with simulated annealing and whole profile pattern matching, and refined using rigid-body Rietveld refinement. RAN-B form I is a monoclinic polymorph with cell parameters: a = 7.317(2), b = 9.021(2), c = 25.098(6) A, beta = 95.690(1) degrees and space group P2(1)/c. The form II is orthorhombic: a = 31.252(4), b = 13.052(2), c = 8.0892(11) A with space group Pbca. In RAN-B polymorphs, the nitro group is involved in a strong intramolecular hydrogen bond responsible for the existence of a Z configuration in the enamine portion of the molecules. A tail to tail packing motif can be denoted via intermolecular hydrogen bonds. The crystal structures of RAN-B forms are compared to those of RAN-HCl polymorphs. RAN-B polymorphs are monotropic polymorphic pairs.

  4. Spore germination based assay for monitoring antibiotic residues in milk at dairy farm.

    PubMed

    Kumar, Naresh; Raghu, Hirikyathanahalli Vishweswaraiah; Kumar, Abhishek; Haldar, Lopamudra; Khan, Alia; Rane, Sharmila; Malik, Ravinder Kumar

    2012-07-01

    Spore germination based assay involves the transformation of dormant spores of Bacillus stearothermophilus 953 into active vegetative cells. The inhibition of germination process specifically in presence of antibiotic residues was used as a novel approach for monitoring target contaminants in milk. The indicator organism i.e., B. stearothermophilus 953 was initially allowed to sporulate by seeding in sporulation medium and incubating at 55 °C for 18 ± 2 h. The spores exhibited a typical chain behavior as revealed through phase contrast microscopy. The minimal medium inoculated with activated spores was incubated at 64 °C for 2-3 h for germination and outgrowth in presence of specific germinant mixture containing dextrose, whey powder and skimmed milk powder added in specific ratio along with reconstituted milk as negative control and test milk samples. The change in color of the medium from purple to yellow was used as criteria for detection of antibiotic residues in milk. The efficiency of the developed assay was evaluated through a surveillance study on 228 samples of raw, pasteurized and dried milks and results were compared with AOAC approved microbial receptor assay. The presence of antibiotic level was 10.08 % at Codex maximum residual limit having false positive result only in 0.43 % of the samples. The results of the present investigation suggest that developed spore based assay can be a practical solution to dairy industry for its application at farm level, milk processing units, independent testing and R & D centres in order to comply with the legal requirements set by Codex. PMID:22806162

  5. Labeling technique for nonplanar surfaces based on the combination of a diffractive axilens with digital holography methods

    NASA Astrophysics Data System (ADS)

    Marin, Pablo; Lizana, Angel; Peinado, Alba; Mora-González, Miguel; Campos, Juan

    2015-05-01

    A technique based on a spatial light modulator is proposed for the labeling of nonplanar surfaces. This technique arises from the combination of a general method for generation of digital holograms with a diffractive axilens. Unlike existing methods in which hologram contrast critically decreases out of the focal plane, our proposed approach allows the system to increase the focus depth, resulting in enhanced hologram images out of the focal plane. Two existing methods for hologram generation are theoretically and experimentally compared in terms of efficiency and contrast: the iterative Fourier transform algorithm-based method and the random multiplexing of different lenses method. The most suitable one is selected for the implementation of the new axilens-based technique. Experimental results obtained with the axilens method provide a significant enhancement of the image quality of holograms obtained out of the focal plane when compared with an existing technique. The approach proposed in this manuscript may be of interest in industrial applications, where alphanumeric data must be registered on nonflat surfaces, as in the cases of beverage cans or bottles.

  6. An Intriguing Correlation Based on the Superimposition of Residue Pairs with Inhibitors that Target Protein-Protein Interfaces

    PubMed Central

    Nakadai, Masakazu; Tomida, Shuta; Sekimizu, Kazuhisa

    2016-01-01

    Druggable sites on protein-protein interfaces are difficult to predict. To survey inhibitor-binding sites onto which residues are superimposed at protein-protein interfaces, we analyzed publicly available information for 39 inhibitors that target the protein-protein interfaces of 8 drug targets. By focusing on the differences between residues that were superimposed with inhibitors and non-superimposed residues, we observed clear differences in the distances and changes in the solvent-accessible surface areas (∆SASA). Based on the observation that two or more residues were superimposed onto inhibitors in 37 (95%) of 39 protein-inhibitor complexes, we focused on the two-residue relationships. Application of a cross-validation procedure confirmed a linear negative correlation between the absolute value of the dihedral angle and the sum of the ∆SASAs of the residues. Finally, we applied the regression equation of this correlation to four inhibitors that bind to new sites not bound by the 39 inhibitors as well as additional inhibitors of different targets. Our results shed light on the two-residue correlation between the absolute value of the dihedral angle and the sum of the ∆SASA, which may be a useful relationship for identifying the key two-residues as potential targets of protein-protein interfaces. PMID:26730437

  7. A Truncated Nuclear Norm Regularization Method Based on Weighted Residual Error for Matrix Completion.

    PubMed

    Qing Liu; Zhihui Lai; Zongwei Zhou; Fangjun Kuang; Zhong Jin

    2016-01-01

    Low-rank matrix completion aims to recover a matrix from a small subset of its entries and has received much attention in the field of computer vision. Most existing methods formulate the task as a low-rank matrix approximation problem. A truncated nuclear norm has recently been proposed as a better approximation to the rank of matrix than a nuclear norm. The corresponding optimization method, truncated nuclear norm regularization (TNNR), converges better than the nuclear norm minimization-based methods. However, it is not robust to the number of subtracted singular values and requires a large number of iterations to converge. In this paper, a TNNR method based on weighted residual error (TNNR-WRE) for matrix completion and its extension model (ETNNR-WRE) are proposed. TNNR-WRE assigns different weights to the rows of the residual error matrix in an augmented Lagrange function to accelerate the convergence of the TNNR method. The ETNNR-WRE is much more robust to the number of subtracted singular values than the TNNR-WRE, TNNR alternating direction method of multipliers, and TNNR accelerated proximal gradient with Line search methods. Experimental results using both synthetic and real visual data sets show that the proposed TNNR-WRE and ETNNR-WRE methods perform better than TNNR and Iteratively Reweighted Nuclear Norm (IRNN) methods. PMID:26625414

  8. The role of continuity in residual-based variational multiscale modeling of turbulence

    NASA Astrophysics Data System (ADS)

    Akkerman, I.; Bazilevs, Y.; Calo, V. M.; Hughes, T. J. R.; Hulshoff, S.

    2008-02-01

    This paper examines the role of continuity of the basis in the computation of turbulent flows. We compare standard finite elements and non-uniform rational B-splines (NURBS) discretizations that are employed in Isogeometric Analysis (Hughes et al. in Comput Methods Appl Mech Eng, 194:4135 4195, 2005). We make use of quadratic discretizations that are C 0-continuous across element boundaries in standard finite elements, and C 1-continuous in the case of NURBS. The variational multiscale residual-based method (Bazilevs in Isogeometric analysis of turbulence and fluid-structure interaction, PhD thesis, ICES, UT Austin, 2006; Bazilevs et al. in Comput Methods Appl Mech Eng, submitted, 2007; Calo in Residual-based multiscale turbulence modeling: finite volume simulation of bypass transition. PhD thesis, Department of Civil and Environmental Engineering, Stanford University, 2004; Hughes et al. in proceedings of the XXI international congress of theoretical and applied mechanics (IUTAM), Kluwer, 2004; Scovazzi in Multiscale methods in science and engineering, PhD thesis, Department of Mechanical Engineering, Stanford Universty, 2004) is employed as a turbulence modeling technique. We find that C 1-continuous discretizations outperform their C 0-continuous counterparts on a per-degree-of-freedom basis. We also find that the effect of continuity is greater for higher Reynolds number flows.

  9. Moment closures based on minimizing the residual of the PN angular expansion in radiation transport

    NASA Astrophysics Data System (ADS)

    Zheng, Weixiong; McClarren, Ryan G.

    2016-06-01

    In this work we present two new closures for the spherical harmonics (PN) method in slab geometry transport problems. Our approach begins with an analysis of the squared-residual of the transport equation where we show that the standard truncation and diffusive closures do not minimize the residual of the PN expansion. Based on this analysis we derive two models, a moment-limited diffusive (ML DN) closure and a transient PN (TPN) closure that attempt to address shortcomings of common closures. The form of these closures is similar to flux-limiters for diffusion with the addition of a time-derivative in the definition of the closure. Numerical results on a pulsed plane source problem, the Gordian knot of slab-geometry transport problems, indicate that our new closure outperforms existing linear closures. Additionally, on a deep penetration problem we demonstrate that the TPN closure does not suffer from the artificial shocks that can arise in the MN entropy-based closure. Finally, results for Reed's problem demonstrate that the TPN solution is as accurate as the PN+3 solution. We further extend the TPN closure to 2D Cartesian geometry. The line source test problem demonstrates the model effectively damps oscillations and negative densities.

  10. The Adaptive Optics Lucky Imager: Diffraction limited imaging at visible wavelengths with large ground-based telescopes

    NASA Astrophysics Data System (ADS)

    Crass, Jonathan; Mackay, Craig; King, David; Rebolo-López, Rafael; Labadie, Lucas; Puga, Marta; Oscoz, Alejandro; González Escalera, Victor; Pérez Garrido, Antonio; López, Roberto; Pérez-Prieto, Jorge; Rodríguez-Ramos, Luis; Velasco, Sergio; Villó, Isidro

    2015-01-01

    One of the continuing challenges facing astronomers today is the need to obtain ever higher resolution images of the sky. Whether studying nearby crowded fields or distant objects, with increased resolution comes the ability to probe systems in more detail and advance our understanding of the Universe. Obtaining these high-resolution images at visible wavelengths however has previously been limited to the Hubble Space Telescope (HST) due to atmospheric effects limiting the spatial resolution of ground-based telescopes to a fraction of their potential. With HST now having a finite lifespan, it is prudent to investigate other techniques capable of providing these kind of observations from the ground. Maintaining this capability is one of the goals of the Adaptive Optics Lucky Imager (AOLI).Achieving the highest resolutions requires the largest telescope apertures, however, this comes at the cost of increased atmospheric distortion. To overcome these atmospheric effects, there are two main techniques employed today: adaptive optics (AO) and lucky imaging. These techniques individually are unable to provide diffraction limited imaging in the visible on large ground-based telescopes; AO currently only works at infrared wavelengths while lucky imaging reduces in effectiveness on telescopes greater than 2.5 metres in diameter. The limitations of both techniques can be overcome by combing them together to provide diffraction limited imaging at visible wavelengths on the ground.The Adaptive Optics Lucky Imager is being developed as a European collaboration and combines AO and lucky imaging in a dedicated instrument for the first time. Initially for use on the 4.2 metre William Herschel Telescope, AOLI uses a low-order adaptive optics system to reduce the effects of atmospheric turbulence before imaging with a lucky imaging based science detector. The AO system employs a novel type of wavefront sensor, the non-linear Curvature Wavefront Sensor (nlCWFS) which provides

  11. Estimating emissions from crop residue open burning in China based on statistics and MODIS fire products.

    PubMed

    Li, Jing; Bo, Yu; Xie, Shaodong

    2016-06-01

    With the objective of reducing the large uncertainties in the estimations of emissions from crop residue open burning, an improved method for establishing emission inventories of crop residue open burning at a high spatial resolution of 0.25°×0.25° and a temporal resolution of 1month was established based on the moderate resolution imaging spectroradiometer (MODIS) Thermal Anomalies/Fire Daily Level3 Global Product (MOD/MYD14A1). Agriculture mechanization ratios and regional crop-specific grain-to-straw ratios were introduced to improve the accuracy of related activity data. Locally observed emission factors were used to calculate the primary pollutant emissions. MODIS satellite data were modified by combining them with county-level agricultural statistical data, which reduced the influence of missing fire counts caused by their small size and cloud cover. The annual emissions of CO2, CO, CH4, nonmethane volatile organic compounds (NMVOCs), N2O, NOx, NH3, SO2, fine particles (PM2.5), organic carbon (OC), and black carbon (BC) were 150.40, 6.70, 0.51, 0.88, 0.01, 0.13, 0.07, 0.43, 1.09, 0.34, and 0.06Tg, respectively, in 2012. Crop residue open burning emissions displayed typical seasonal and spatial variation. The highest emission regions were the Yellow-Huai River and Yangtse-Huai River areas, and the monthly emissions were highest in June (37%). Uncertainties in the emission estimates, measured as 95% confidence intervals, range from a low of within ±126% for N2O to a high of within ±169% for NH3.

  12. Estimating emissions from crop residue open burning in China based on statistics and MODIS fire products.

    PubMed

    Li, Jing; Bo, Yu; Xie, Shaodong

    2016-06-01

    With the objective of reducing the large uncertainties in the estimations of emissions from crop residue open burning, an improved method for establishing emission inventories of crop residue open burning at a high spatial resolution of 0.25°×0.25° and a temporal resolution of 1month was established based on the moderate resolution imaging spectroradiometer (MODIS) Thermal Anomalies/Fire Daily Level3 Global Product (MOD/MYD14A1). Agriculture mechanization ratios and regional crop-specific grain-to-straw ratios were introduced to improve the accuracy of related activity data. Locally observed emission factors were used to calculate the primary pollutant emissions. MODIS satellite data were modified by combining them with county-level agricultural statistical data, which reduced the influence of missing fire counts caused by their small size and cloud cover. The annual emissions of CO2, CO, CH4, nonmethane volatile organic compounds (NMVOCs), N2O, NOx, NH3, SO2, fine particles (PM2.5), organic carbon (OC), and black carbon (BC) were 150.40, 6.70, 0.51, 0.88, 0.01, 0.13, 0.07, 0.43, 1.09, 0.34, and 0.06Tg, respectively, in 2012. Crop residue open burning emissions displayed typical seasonal and spatial variation. The highest emission regions were the Yellow-Huai River and Yangtse-Huai River areas, and the monthly emissions were highest in June (37%). Uncertainties in the emission estimates, measured as 95% confidence intervals, range from a low of within ±126% for N2O to a high of within ±169% for NH3. PMID:27266312

  13. Proposal for field-based definition of soil bound pesticide residues.

    PubMed

    Boesten, J J T I

    2016-02-15

    The environmental significance of soil bound pesticide residues (SBPR) is potentially large because approximately one third of the applied mass of the pesticides in agriculture ends up as SBPR. At EU level, there is little regulatory guidance available on the environmental risk assessment of SBPR in spite of some 50 years of SBPR research. This lack of guidance is partially caused by the fact that the current definitions of SBPR are founded on non-extractability in soil in the laboratory whereas for the environmental risk assessment not the soil in the laboratory but the soil in the field is the system of interest. Therefore a definition of SBPR is proposed that is based on the field soil: a molecule (further called 'the mother molecule') is soil bound if a relevant part of this molecule has become part of the solid phase in the soil and if this relevant part will never be released again to the liquid phase in soil under relevant field conditions in the form of this mother molecule or in the form of another molecule that may possibly raise environmental or human toxicological concerns. This mother molecule may be the parent substance that is applied to the soil but it may also be a metabolite of this parent substance. A consequence of the definition is that the SBPR terminology becomes more precise because the mother molecule of the soil bound residue has to be specified. A further consequence is that very strong but reversible sorption of molecules such as paraquat is not considered soil-bound residue anymore (as may be demonstrated by a self-exchange extraction procedure). Furthermore, the definition requires that risk managers have to define what they consider as 'relevant field conditions' (e.g. include also changes of agricultural fields into forests?).

  14. Residual Monte Carlo high-order solver for Moment-Based Accelerated Thermal Radiative Transfer equations

    SciTech Connect

    Willert, Jeffrey Park, H.

    2014-11-01

    In this article we explore the possibility of replacing Standard Monte Carlo (SMC) transport sweeps within a Moment-Based Accelerated Thermal Radiative Transfer (TRT) algorithm with a Residual Monte Carlo (RMC) formulation. Previous Moment-Based Accelerated TRT implementations have encountered trouble when stochastic noise from SMC transport sweeps accumulates over several iterations and pollutes the low-order system. With RMC we hope to significantly lower the build-up of statistical error at a much lower cost. First, we display encouraging results for a zero-dimensional test problem. Then, we demonstrate that we can achieve a lower degree of error in two one-dimensional test problems by employing an RMC transport sweep with multiple orders of magnitude fewer particles per sweep. We find that by reformulating the high-order problem, we can compute more accurate solutions at a fraction of the cost.

  15. Phthalate residue in goat milk-based infant formulas manufactured in China.

    PubMed

    Ge, W P; Yang, X J; Wu, X Y; Wang, Z; Geng, W; Guo, C F

    2016-10-01

    Phthalates adversely affect the male reproductive system in humans. Through gas chromatography-mass spectrometry analysis, we investigated the residual profile and levels of 15 phthalates in 90 goat milk-based infant formulas from 15 commercial brands of 10 dairy enterprises located in Shaanxi Province, China. In general, dibutyl phthalate was the most detected phthalate, followed by bis(2-ethylhexyl) phthalate, diisobutyl phthalate, and dimethyl phthalate; their geometric mean concentrations in the formulas were 38.1, 24.2, 16.6, and 8.7μg/kg, respectively. Other phthalates were not detected in the investigated samples. No significant differences were found in the phthalate levels among different stages of infant formulas, even though the samples were packaged in different types of containers. These findings demonstrate that goat milk-based infant formulas may represent the main source of exposure to phthalates in infants. PMID:27522423

  16. High-sensitivity neutron diffraction of membranes: Location of the Schiff base end of the chromophore of bacteriorhodopsin

    SciTech Connect

    Heyn, M.P.; Westerhausen, J.; Wallat, I.; Seiff, F. )

    1988-04-01

    Three important events in the functional cycle of bacteriorhodopsin occur at the chromophore: the primary absorption of light, the isomerization from the all-trans to the 13-cis form, and the deprotonation and reprotonation of its Schiff base. The protonated Schiff base linkage of the chromophore with lysine-216 plays an essential role in the color regulation of the pigment and is most likely directly involved in the charge translocation of this light-driven proton pump. Although much is known about the structure of the protein, the position of this key functional group has not yet been determined. The authors have synthesized a retinal in which the five protons closest to the Schiff base are replaced by deuterons. The labeled retinal was spontaneously incorporated into bacteriorhodopsin by using a mutant of Halobacterium halobium that is deficient in the synthesis of retinal. The position of the labeled Schiff base end of the chromophore was determined in the two-dimensional projected density of dark-adapted bacteriorhodopsin by neutron diffraction. The result fits very well with their previous work using retinals that were selectively deuterated in the middle of the polyene chain or in the cyclohexene ring. A coherent structure emerges with the three labeled positions on one line, separated by distances that are in good agreement with the tilt angle of the polyene chain (about 20{degree}). The results show that it is possible to locate a small group containing as few as five deuterons in a membrane protein of molecular weight 27,000.

  17. QuEChERS-based method for the determination of carbamate residues in aromatic herbs by UHPLC-MS/MS.

    PubMed

    Nantia, Edouard Akono; Moreno-González, David; Manfo, Faustin P T; Gámiz-Gracia, Laura; García-Campaña, Ana M

    2017-02-01

    A new reliable, fast and highly sensitive method based on ultra-high performance liquid chromatography tandem mass spectrometry has been developed and validated for the determination of 28 carbamates in aromatic herbs. A modified QuEChERS-based method was optimized for the extraction of carbamate residues from a wide variety of fresh herbal products. The proposed method allowed recoveries higher than 72%, achieving quantification limits of 2μgkg(-1), therefore below maximum residue limits established for this type of samples. The combination of QuEChERS with UHPLC-MS/MS introduces a high-throughput methodology for the monitoring of these residues in this type of matrices scarcely explored. The analysis of the real samples revealed that several samples sold in the European Union and in the North West region of Cameroon contain pesticides in concentrations below the maximum residue limits.

  18. QuEChERS-based method for the determination of carbamate residues in aromatic herbs by UHPLC-MS/MS.

    PubMed

    Nantia, Edouard Akono; Moreno-González, David; Manfo, Faustin P T; Gámiz-Gracia, Laura; García-Campaña, Ana M

    2017-02-01

    A new reliable, fast and highly sensitive method based on ultra-high performance liquid chromatography tandem mass spectrometry has been developed and validated for the determination of 28 carbamates in aromatic herbs. A modified QuEChERS-based method was optimized for the extraction of carbamate residues from a wide variety of fresh herbal products. The proposed method allowed recoveries higher than 72%, achieving quantification limits of 2μgkg(-1), therefore below maximum residue limits established for this type of samples. The combination of QuEChERS with UHPLC-MS/MS introduces a high-throughput methodology for the monitoring of these residues in this type of matrices scarcely explored. The analysis of the real samples revealed that several samples sold in the European Union and in the North West region of Cameroon contain pesticides in concentrations below the maximum residue limits. PMID:27596428

  19. Oil crop biomass residue-based media for enhanced algal lipid production.

    PubMed

    Wang, Zhen; Ma, Xiaochen; Zhou, Wenguang; Min, Min; Cheng, Yanling; Chen, Paul; Shi, Jian; Wang, Qin; Liu, Yuhuan; Ruan, Roger

    2013-10-01

    The aim of this study was to evaluate the use of hydrolysates from acid hydrolysis of four different oil crop biomass residues (OCBR) as low cost culture media for algae growth. The one-factor-at-a-time method was used to design a series of experiments to optimize the acid hydrolysis conditions through examining the total nitrogen, total phosphorus, chemical oxygen demand, and ammonia nitrogen in the hydrolysates. The optimal conditions were found to be using 3% sulfuric acid and hydrolyzing residues at 90 °C for 20 h. The hydrolysates (OCBR media) produced under the optimal conditions were used to cultivate the two algae strains, namely UM258 and UM268. The results from 5 days of cultivation showed that the OCBR media supported faster algae growth with maximal algal biomass yield of 2.7 and 3 g/L, respectively. Moreover, the total lipids for UM258 and UM268 were 54 and 35%, respectively, after 5 days of cultivation, which suggested that the OCBR media allowed the algae strains to accumulate higher lipids probably due to high C/N ratio. Furthermore, over 3% of omega-3 fatty acid (EPA) was produced for the two algae strains. In conclusion, OCBR media are excellent alternative for algae growth and have a great potential for large-scale production of algae-based ingredients for biodiesel as well as high-value food and pharmaceutical products.

  20. A residue-based toxicokinetic model for pulse-exposure toxicity in aquatic systems

    SciTech Connect

    Hickie, B.E.; McCarty, L.S.; Dixon, D.G.

    1995-12-01

    This pulse-exposure model (PULSETOX) is based on the simple one-compartment first-order kinetics (1CFOK) equation. It tracks the accumulation of waterborne organic chemicals by fish and predicts acute toxicity by means of previously established relationships between whole-body residues and lethality. The predictive capabilities of the model were tested with a data set of 27 acute pulse-exposure lethality tests with larval fathead minnows (Pimephales promelas) exposed to pentachlorophenol (PCP). Tests included eight single exposures (2 to 96 h) and 19 multiple exposures, which varied in the number (2 to 15) and duration (2 to 24 h) of pulses, and time interval between pulses (6 to 24 h). Experimental work included determination of 1CFOK kinetics parameters from [{sup 14}C]PCP uptake and clearance, and from time-toxicity curves. Lethality was expected in any exposure regime where the fish reaches or exceeds the critical body residue (CBR) of 0.30 mmol PCP/kg fish (SD, {+-} 0.02; n = 11). Using the CBR endpoint, the model accounted for between 90 and 93% of variability in the observed lethality data, depending on the toxicokinetic parameters employed. Predictive power of the model was optimized by using kinetics parameters derived from the toxicity curve for pulse-toxicity tests as shown by the regression: predicted LC50 = 1.04 {center_dot} (observed LC50) + 0.01 (p < 0.001, r{sup 2} = 0.94, n = 27).

  1. Effect of additives on the tensile performance and protein solubility of industrial oilseed residual based plastics.

    PubMed

    Newson, William R; Kuktaite, Ramune; Hedenqvist, Mikael S; Gällstedt, Mikael; Johansson, Eva

    2014-07-16

    Ten chemical additives were selected from the literature for their proposed modifying activity in protein-protein interactions. These consisted of acids, bases, reducing agents, and denaturants and were added to residual deoiled meals of Crambe abyssinica (crambe) and Brassica carinata (carinata) to modify the properties of plastics produced through hot compression molding at 130 °C. The films produced were examined for tensile properties, protein solubility, molecular weight distribution, and water absorption. Of the additives tested, NaOH had the greatest positive effect on tensile properties, with increases of 105% in maximum stress and 200% in strain at maximum stress for crambe and a 70% increase in strain at maximum stress for carinata. Stiffness was not increased by any of the applied additives. Changes in tensile strength and elongation for crambe and elongation for carinata were related to changes in protein solubility. Increased pH was the most successful in improving the protein aggregation and mechanical properties within the complex chemistry of residual oilseed meals.

  2. Insights into the mechanisms of mercury sorption onto aluminum based drinking water treatment residuals.

    PubMed

    Deliz Quiñones, Katherine; Hovsepyan, Anna; Oppong-Anane, Akua; Bonzongo, Jean-Claude J

    2016-04-15

    Several studies have demonstrated the ability of drinking water treatment residuals (WTRs) to efficiently sorb metal cations from aqueous solutions. Reported results have stimulated interest on the potential use of WTRs as sorbent for metal removal from contaminated aqueous effluents as well as in metal immobilization in contaminated soils. However, knowledge on mechanisms of metal sorption by WTRs remains very limited and data on the long-term stability of formed metal-WTR complexes as a function of changing key environmental parameters are lacking. In this study, chemical selective sequential extraction (SSE), scanning electron microscopy combined with X-ray energy dispersive spectrometer (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) were used to gain insight into the different mechanisms of mercury (Hg) binding to aluminum based WTR (Al-WTRs). Results from sorption studies show that a significant portion of Hg becomes incorporated in the operationally defined residual fraction of Al-WTRs, and therefore, not prone to dissolution and mobility. The results of solid phase analyses suggested that Hg immobilization by Al-WTR occurs largely through its binding to oxygen donor atoms of mineral ligands driven by a combination of electrostatic forces and covalent bonding. PMID:26780705

  3. Effect of additives on the tensile performance and protein solubility of industrial oilseed residual based plastics.

    PubMed

    Newson, William R; Kuktaite, Ramune; Hedenqvist, Mikael S; Gällstedt, Mikael; Johansson, Eva

    2014-07-16

    Ten chemical additives were selected from the literature for their proposed modifying activity in protein-protein interactions. These consisted of acids, bases, reducing agents, and denaturants and were added to residual deoiled meals of Crambe abyssinica (crambe) and Brassica carinata (carinata) to modify the properties of plastics produced through hot compression molding at 130 °C. The films produced were examined for tensile properties, protein solubility, molecular weight distribution, and water absorption. Of the additives tested, NaOH had the greatest positive effect on tensile properties, with increases of 105% in maximum stress and 200% in strain at maximum stress for crambe and a 70% increase in strain at maximum stress for carinata. Stiffness was not increased by any of the applied additives. Changes in tensile strength and elongation for crambe and elongation for carinata were related to changes in protein solubility. Increased pH was the most successful in improving the protein aggregation and mechanical properties within the complex chemistry of residual oilseed meals. PMID:24971658

  4. A second order residual based predictor-corrector approach for time dependent pollutant transport

    NASA Astrophysics Data System (ADS)

    Pavan, S.; Hervouet, J.-M.; Ricchiuto, M.; Ata, R.

    2016-08-01

    We present a second order residual distribution scheme for scalar transport problems in shallow water flows. The scheme, suitable for the unsteady cases, is obtained adapting to the shallow water context the explicit Runge-Kutta schemes for scalar equations [1]. The resulting scheme is decoupled from the hydrodynamics yet the continuity equation has to be considered in order to respect some important numerical properties at discrete level. Beyond the classical characteristics of the residual formulation presented in [1,2], we introduce the possibility to iterate the corrector step in order to improve the accuracy of the scheme. Another novelty is that the scheme is based on a precise monotonicity condition which guarantees the respect of the maximum principle. We thus end up with a scheme which is mass conservative, second order accurate and monotone. These properties are checked in the numerical tests, where the proposed approach is also compared to some finite volume schemes on unstructured grids. The results obtained show the interest in adopting the predictor-corrector scheme for pollutant transport applications, where conservation of the mass, monotonicity and accuracy are the most relevant concerns.

  5. Multi-residue detection of pesticides using a sensitive immunochip assay based on nanogold enhancement.

    PubMed

    Lan, Meijing; Guo, Yirong; Zhao, Ying; Liu, Yihua; Gui, Wenjun; Zhu, Guonian

    2016-09-28

    This paper describes the development of a new multiplex immunoassay for simultaneous detection of seven pesticides (triazophos, methyl-parathion, fenpropathrin, carbofuran, thiacloprid, chlorothalonil, and carbendazim). Sixteen pairs of pesticide antibodies and antigens were screened for reactivity and cross-reaction. A microarray chip consisting of seven antigens immobilized on a nitrocellulose membrane was then constructed. Nanogold was employed for labeling and signal amplification to obtain a sensitive colorimetric immunoassay. The direct and indirect detection formats were further compared using primary antibody-gold and secondary antibody-gold conjugates as tracers. An integrated 7-plex immunochip assay based on the indirect model was established and optimized. The detection limits for the pesticides were 0.02-6.45 ng mL(-1), which meets detection requirements for pesticide residues. Naked-eye assessment showed the visual detection limits of the assay ranged from 1 to 100 ng mL(-1). Spiked recovery results demonstrated that the immunochip assay had potential for multi-analysis of pesticide residues in vegetables and fruits. The proposed microarray methodology is a flexible and versatile tool, which can be applied to other competitive multiplex immunoassays for small molecular compounds. PMID:27619097

  6. Multi-residue detection of pesticides using a sensitive immunochip assay based on nanogold enhancement.

    PubMed

    Lan, Meijing; Guo, Yirong; Zhao, Ying; Liu, Yihua; Gui, Wenjun; Zhu, Guonian

    2016-09-28

    This paper describes the development of a new multiplex immunoassay for simultaneous detection of seven pesticides (triazophos, methyl-parathion, fenpropathrin, carbofuran, thiacloprid, chlorothalonil, and carbendazim). Sixteen pairs of pesticide antibodies and antigens were screened for reactivity and cross-reaction. A microarray chip consisting of seven antigens immobilized on a nitrocellulose membrane was then constructed. Nanogold was employed for labeling and signal amplification to obtain a sensitive colorimetric immunoassay. The direct and indirect detection formats were further compared using primary antibody-gold and secondary antibody-gold conjugates as tracers. An integrated 7-plex immunochip assay based on the indirect model was established and optimized. The detection limits for the pesticides were 0.02-6.45 ng mL(-1), which meets detection requirements for pesticide residues. Naked-eye assessment showed the visual detection limits of the assay ranged from 1 to 100 ng mL(-1). Spiked recovery results demonstrated that the immunochip assay had potential for multi-analysis of pesticide residues in vegetables and fruits. The proposed microarray methodology is a flexible and versatile tool, which can be applied to other competitive multiplex immunoassays for small molecular compounds.

  7. Development and Characterization of Edible Films Based on Fruit and Vegetable Residues.

    PubMed

    Andrade, Roberta M S; Ferreira, Mariana S L; Gonçalves, Édira C B A

    2016-02-01

    Edible films were developed from the solid residue of the processing of whole fruits and vegetables. The solid residue, processed into flour (FVR flour) was chemically and structurally characterized by microstructure, elemental composition, structural links, and moisture sorption isotherm. Films were prepared by casting using aqueous extracts of 8% and 10% of flour (w/w) and characterized in terms of thickness, water solubility, mechanical properties, water vapor permeability, and Fourier transform infrared (FTIR). The analysis of microstructure and elemental composition, performed on flour (mean particle size 350 μm), showed an essentially granular aspect, with the presence of fibrous particles having potassium as one of the most abundant elements. FTIR results showed similarity between the characteristic bands of other raw materials used in edible films. The sorption isotherm of FVR flour showed a typical profile of foods rich in soluble components, such as sugars. Dried films presented an average thickness of 0.263 ± 0.003 mm, a homogenous aspect, bright yellow color, pronounced fruit flavor, and high water solubility. The FTIR spectra of the edible films revealed that addition of potato skin flour did not change the molecular conformation. Moreover, the films presented low tensile strength at break when compared with fruit starch-based films.

  8. Development and Characterization of Edible Films Based on Fruit and Vegetable Residues.

    PubMed

    Andrade, Roberta M S; Ferreira, Mariana S L; Gonçalves, Édira C B A

    2016-02-01

    Edible films were developed from the solid residue of the processing of whole fruits and vegetables. The solid residue, processed into flour (FVR flour) was chemically and structurally characterized by microstructure, elemental composition, structural links, and moisture sorption isotherm. Films were prepared by casting using aqueous extracts of 8% and 10% of flour (w/w) and characterized in terms of thickness, water solubility, mechanical properties, water vapor permeability, and Fourier transform infrared (FTIR). The analysis of microstructure and elemental composition, performed on flour (mean particle size 350 μm), showed an essentially granular aspect, with the presence of fibrous particles having potassium as one of the most abundant elements. FTIR results showed similarity between the characteristic bands of other raw materials used in edible films. The sorption isotherm of FVR flour showed a typical profile of foods rich in soluble components, such as sugars. Dried films presented an average thickness of 0.263 ± 0.003 mm, a homogenous aspect, bright yellow color, pronounced fruit flavor, and high water solubility. The FTIR spectra of the edible films revealed that addition of potato skin flour did not change the molecular conformation. Moreover, the films presented low tensile strength at break when compared with fruit starch-based films. PMID:26766297

  9. Insights into the mechanisms of mercury sorption onto aluminum based drinking water treatment residuals.

    PubMed

    Deliz Quiñones, Katherine; Hovsepyan, Anna; Oppong-Anane, Akua; Bonzongo, Jean-Claude J

    2016-04-15

    Several studies have demonstrated the ability of drinking water treatment residuals (WTRs) to efficiently sorb metal cations from aqueous solutions. Reported results have stimulated interest on the potential use of WTRs as sorbent for metal removal from contaminated aqueous effluents as well as in metal immobilization in contaminated soils. However, knowledge on mechanisms of metal sorption by WTRs remains very limited and data on the long-term stability of formed metal-WTR complexes as a function of changing key environmental parameters are lacking. In this study, chemical selective sequential extraction (SSE), scanning electron microscopy combined with X-ray energy dispersive spectrometer (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) were used to gain insight into the different mechanisms of mercury (Hg) binding to aluminum based WTR (Al-WTRs). Results from sorption studies show that a significant portion of Hg becomes incorporated in the operationally defined residual fraction of Al-WTRs, and therefore, not prone to dissolution and mobility. The results of solid phase analyses suggested that Hg immobilization by Al-WTR occurs largely through its binding to oxygen donor atoms of mineral ligands driven by a combination of electrostatic forces and covalent bonding.

  10. Modeling of copper(II) sites in proteins based on histidyl and glycyl residues.

    PubMed

    Orfei, Marco; Alcaro, Maria Claudia; Marcon, Giordana; Chelli, Mario; Ginanneschi, Mauro; Kozlowski, Henryk; Brasuń, Justyna; Messori, Luigi

    2003-11-01

    The complexes between copper(II) and four synthetic tetrapeptides bearing a single histidine residue within the sequence (AcHGGG, AcGHGG, AcGGHG and AcGGGH, respectively), have been investigated by potentiometric and spectroscopic methods (UV-Vis, circular dichroism and electron paramagnetic resonance). Potentiometric studies in the pH range 4-12 allowed identification and quantitative determination of the species present in solution for each copper-peptide complex. In all cases, upon raising pH, copper(II) coordination starts from the imidazole nitrogen of the His; afterwards three deprotonated amide nitrogens are progressively involved in copper coordination, except in the case of AcGHGG. Based on the potentiometric and spectroscopic results, detailed molecular structures are proposed for the dominant copper(II) tetrapeptide species existing in solution, either at neutral or alkaline pH. The structural consequences of the presence and of the location of a unique histidine residue within the tetrameric sequence are specifically analyzed. Results are discussed in relation to the modeling of copper(II) binding sites in proteins, particular emphasis being devoted to the copper complexes of the prion protein. PMID:14511892

  11. Residual stresses in material processing

    SciTech Connect

    Kozaczek, K.J.; Watkins, T.R.; Hubbard, C.R.; Wang, Xun-Li; Spooner, S.

    1994-09-01

    Material manufacturing processes often introduce residual stresses into the product. The residual stresses affect the properties of the material and often are detrimental. Therefore, the distribution and magnitude of residual stresses in the final product are usually an important factor in manufacturing process optimization or component life prediction. The present paper briefly discusses the causes of residual stresses. It then adresses the direct, nondestructive methods of residual stress measurement by X-ray and neutron diffraction. Examples are presented to demonstrate the importance of residual stress measurement in machining and joining operations.

  12. Advanced Techniques for In-Situ Monitoring of Phase Transformations During Welding Using Synchrotron-Based X-Ray Diffraction

    SciTech Connect

    Elmer, J W; Palmer, T A; Zhang, W; DebRoy, T

    2005-06-05

    Understanding the evolution of microstructure in welds is an important goal of welding research because of the strong correlation between weld microstructure and weld properties. To achieve this goal it is important to develop a quantitative measure of phase transformations encountered during welding in order to ultimately develop methods for predicting weld microstructures from the characteristics of the welding process. To aid in this effort, synchrotron radiation methods have been developed at Lawrence Livermore National Laboratory (LLNL) for direct observation of microstructure evolution during welding. Using intense, highly collimated synchrotron radiation, the atomic structure of the weld heat affected and fusion zones can be probed in real time. Two synchrotron-based techniques, known as spatially resolved (SRXRD) and time resolved (TRXRD) x-ray diffraction, have been developed for these investigations. These techniques have now been used to investigate welding induced phase transformations in titanium alloys, low alloy steels, and stainless steel alloys. This paper will provide a brief overview of these methods and will discuss microstructural evolution during the welding of low carbon (AISI 1005) and medium carbon (AISI 1045) steels where the different levels of carbon influence the evolution of microstructures during welding.

  13. Improving focus performance at litho using diffraction-based focus metrology, novel calibration methods, interface, and control loop

    NASA Astrophysics Data System (ADS)

    Hu, Jiarui; Chen, Y. L.; Chen, K. H.; Lee, Brian; Tsai, Frankie; Ke, C. M.; Liao, C. H.; Ngo, Desmond; Gosali, Benny; Tijssen, Robin; Huang, Vincent; Tu, Ward; Noot, Marc; Escalante Marun, Maryana; Leewis, Christian; Luijten, Carlo; Staals, Frank; Van Veen, Martijn; Furthner, Francois; Young, Stuart; Bhattacharyya, Kaustuve

    2016-03-01

    In advanced optical lithography the requirements of focus control continues to tighten. Usable depth of focus (DoF) is already quite low due to typical sources of focus errors, such as topography, wafer warpage and the thickness of photoresist. And now the usable DoF is further decreased by hotspots (design and imaging hotspots). All these have put extra challenges to improve focus metrology, scanner focus stability calibrations and on-product correction mechanisms. Asymmetric focus targets are developed to address robustness in focus measurements using diffraction-based focus (DBF and μDBF) metrology. A new layout specific calibration methodology is introduced for baseline focus setup and control in order to improve scanner focus uniformity and stability using the measurements of the above mentioned asymmetric targets. A similar metrology is also used for on product focus measurements. Moreover, a few novel alternative methods are also investigated for on-product focus measurements. Data shows good correlation between DBF and process on record (POR) method using traditional FEM. The new focus calibration demonstrated robustness, stability and speed. This technical publication will report the data from all the above activities including results from various product layers.

  14. Quantitative phase analysis from powder diffraction using de Rietveld method in hydrogen storage alloys based on TiCr

    NASA Astrophysics Data System (ADS)

    Martinez, A.; Bellon, D.; Reina, L.

    2016-08-01

    Hydrogen storage is one of the important steps in the implementation of the hydrogen economy; metal hydrides are a promising way to achieve this goal. We present in this work the use of Rietveld analysis to characterize structurally TiCr-based alloys that are able to store hydrogen. TiCruV09, TiCrL1V0.45Nb0.45, TiCr1.1V0.2 Nb0.8, TiCr1.1Nb0.9 alloys were synthesized in an arc furnace under argon atmosphere. The analysis of phases was developed by X-Ray Diffraction (XRD) for further refinement of both the two lattice parameters and the percentage of the phases. Our results confirmed that a structure bcc, mostly combined with a small percentage of Laves phases, leads to obtain important properties in this area. Rietveld analysis was performed by the Fullprof program and this program allows us to obtain the different structural parameters.

  15. Enhancement of low-quality reconstructed digital hologram images based on frequency extrapolation of large objects under the diffraction limit

    NASA Astrophysics Data System (ADS)

    Liu, Ning; Li, Weiliang; Zhao, Dongxue

    2016-06-01

    During the reconstruction of a digital hologram, the reconstructed image is usually degraded by speckle noise, which makes it hard to observe the original object pattern. In this paper, a new reconstructed image enhancement method is proposed, which first reduces the speckle noise using an adaptive Gaussian filter, then calculates the high frequencies that belong to the object pattern based on a frequency extrapolation strategy. The proposed frequency extrapolation first calculates the frequency spectrum of the Fourier-filtered image, which is originally reconstructed from the +1 order of the hologram, and then gives the initial parameters for an iterative solution. The analytic iteration is implemented by continuous gradient threshold convergence to estimate the image level and vertical gradient information. The predicted spectrum is acquired through the analytical iteration of the original spectrum and gradient spectrum analysis. Finally, the reconstructed spectrum of the restoration image is acquired from the synthetic correction of the original spectrum using the predicted gradient spectrum. We conducted our experiment very close to the diffraction limit and used low-quality equipment to prove the feasibility of our method. Detailed analysis and figure demonstrations are presented in the paper.

  16. Prediction of conformational epitopes with the use of a knowledge-based energy function and geometrically related neighboring residue characteristics

    PubMed Central

    2013-01-01

    Background A conformational epitope (CE) in an antigentic protein is composed of amino acid residues that are spatially near each other on the antigen's surface but are separated in sequence; CEs bind their complementary paratopes in B-cell receptors and/or antibodies. CE predication is used during vaccine design and in immuno-biological experiments. Here, we develop a novel system, CE-KEG, which predicts CEs based on knowledge-based energy and geometrical neighboring residue contents. The workflow applied grid-based mathematical morphological algorithms to efficiently detect the surface atoms of the antigens. After extracting surface residues, we ranked CE candidate residues first according to their local average energy distributions. Then, the frequencies at which geometrically related neighboring residue combinations in the potential CEs occurred were incorporated into our workflow, and the weighted combinations of the average energies and neighboring residue frequencies were used to assess the sensitivity, accuracy, and efficiency of our prediction workflow. Results We prepared a database containing 247 antigen structures and a second database containing the 163 non-redundant antigen structures in the first database to test our workflow. Our predictive workflow performed better than did algorithms found in the literature in terms of accuracy and efficiency. For the non-redundant dataset tested, our workflow achieved an average of 47.8% sensitivity, 84.3% specificity, and 80.7% accuracy according to a 10-fold cross-validation mechanism, and the performance was evaluated under providing top three predicted CE candidates for each antigen. Conclusions Our method combines an energy profile for surface residues with the frequency that each geometrically related amino acid residue pair occurs to identify possible CEs in antigens. This combination of these features facilitates improved identification for immuno-biological studies and synthetic vaccine design. CE-KEG is

  17. Method for identification of rigid domains and hinge residues in proteins based on exhaustive enumeration.

    PubMed

    Sim, Jaehyun; Sim, Jun; Park, Eunsung; Lee, Julian

    2015-06-01

    Many proteins undergo large-scale motions where relatively rigid domains move against each other. The identification of rigid domains, as well as the hinge residues important for their relative movements, is important for various applications including flexible docking simulations. In this work, we develop a method for protein rigid domain identification based on an exhaustive enumeration of maximal rigid domains, the rigid domains not fully contained within other domains. The computation is performed by mapping the problem to that of finding maximal cliques in a graph. A minimal set of rigid domains are then selected, which cover most of the protein with minimal overlap. In contrast to the results of existing methods that partition a protein into non-overlapping domains using approximate algorithms, the rigid domains obtained from exact enumeration naturally contain overlapping regions, which correspond to the hinges of the inter-domain bending motion. The performance of the algorithm is demonstrated on several proteins.

  18. Empirical likelihood based detection procedure for change point in mean residual life functions under random censorship.

    PubMed

    Chen, Ying-Ju; Ning, Wei; Gupta, Arjun K

    2016-05-01

    The mean residual life (MRL) function is one of the basic parameters of interest in survival analysis that describes the expected remaining time of an individual after a certain age. The study of changes in the MRL function is practical and interesting because it may help us to identify some factors such as age and gender that may influence the remaining lifetimes of patients after receiving a certain surgery. In this paper, we propose a detection procedure based on the empirical likelihood for the changes in MRL functions with right censored data. Two real examples are also given: Veterans' administration lung cancer study and Stanford heart transplant to illustrate the detecting procedure. Copyright © 2016 John Wiley & Sons, Ltd.

  19. Empirical likelihood based detection procedure for change point in mean residual life functions under random censorship.

    PubMed

    Chen, Ying-Ju; Ning, Wei; Gupta, Arjun K

    2016-05-01

    The mean residual life (MRL) function is one of the basic parameters of interest in survival analysis that describes the expected remaining time of an individual after a certain age. The study of changes in the MRL function is practical and interesting because it may help us to identify some factors such as age and gender that may influence the remaining lifetimes of patients after receiving a certain surgery. In this paper, we propose a detection procedure based on the empirical likelihood for the changes in MRL functions with right censored data. Two real examples are also given: Veterans' administration lung cancer study and Stanford heart transplant to illustrate the detecting procedure. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26936529

  20. Novel residual-based large eddy simulation turbulence models for incompressible magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Sondak, David

    The goal of this work was to develop, introduce, and test a promising computational paradigm for the development of turbulence models for incompressible magnetohydrodynamics (MHD). MHD governs the behavior of an electrically conducting fluid in the presence of an external electromagnetic (EM) field. The incompressible MHD model is used in many engineering and scientific disciplines from the development of nuclear fusion as a sustainable energy source to the study of space weather and solar physics. Many interesting MHD systems exhibit the phenomenon of turbulence which remains an elusive problem from all scientific perspectives. This work focuses on the computational perspective and proposes techniques that enable the study of systems involving MHD turbulence. Direct numerical simulation (DNS) is not a feasible approach for studying MHD turbulence. In this work, turbulence models for incompressible MHD were developed from the variational multiscale (VMS) formulation wherein the solution fields were decomposed into resolved and unresolved components. The unresolved components were modeled with a term that is proportional to the residual of the resolved scales. Two additional MHD models were developed based off of the VMS formulation: a residual-based eddy viscosity (RBEV) model and a mixed model that partners the VMS formulation with the RBEV model. These models are endowed with several special numerical and physics features. Included in the numerical features is the internal numerical consistency of each of the models. Physically, the new models are able to capture desirable MHD physics such as the inverse cascade of magnetic energy and the subgrid dynamo effect. The models were tested with a Fourier-spectral numerical method and the finite element method (FEM). The primary test problem was the Taylor-Green vortex. Results comparing the performance of the new models to DNS were obtained. The performance of the new models was compared to classic and cutting

  1. A novel laser-based approach for cleaning contaminated metallic surfaces coupled with rapid residue analysis

    NASA Astrophysics Data System (ADS)

    Fox, Robert V.; Roberts, Lauren; DeLucia, Frank C.; Miziolek, Andrzej W.; Whitehouse, Andrew I.

    2013-05-01

    We are developing a novel approach for cleaning and confirming contaminated metallic surfaces that is based on laser ablation to clean the surfaces followed closely in time and space by laser analysis of the degree of cleanliness. Laser-based surface cleaning is a well-established technology and is commercially available (e.g., Adapt-Laser). The new development involves the integration of a LIBS (Laser Induced Breakdown Spectroscopy) surface analytical capability to analyze the surface before and right after the laser cleaning step for the presence or absence of unwanted residues. This all-laser approach is being applied to surfaces of steel vessels that have been used for the containment and destruction of chemical munitions. Various processes used for the destruction of chemical munitions result in the creation of oxidized steel surfaces containing residues (e.g., arsenic, mercury) that need to be removed to acceptable levels. In many instances inorganic molecular contaminants become integrated into oxide layers, necessitating complete removal of the oxide layer to achieve ideal levels of surface cleanliness. The focus of this study is on oxidized steel surfaces exposed to thermally decomposed Lewisite, and thus laden with arsenic. We demonstrate here that a commercially-available cleaning laser sufficiently removes the oxide coating and the targeted contaminants from the affected steel surface. Additionally, we demonstrate that LIBS is useful for the identification of arsenic and mercury on steel surfaces before and after laser cleaning, with arsenic being specifically tracked and analyzed at levels less than 1 microgram per square centimeter surface loading. Recent progress and future directions are presented and discussed.

  2. Identification of acid-base catalytic residues of high-Mr thioredoxin reductase from Plasmodium falciparum.

    PubMed

    McMillan, Paul J; Arscott, L David; Ballou, David P; Becker, Katja; Williams, Charles H; Müller, Sylke

    2006-11-01

    High-M(r) thioredoxin reductase from the malaria parasite Plasmodium falciparum (PfTrxR) contains three redox active centers (FAD, Cys-88/Cys-93, and Cys-535/Cys-540) that are in redox communication. The catalytic mechanism of PfTrxR, which involves dithiol-disulfide interchanges requiring acid-base catalysis, was studied by steady-state kinetics, spectral analyses of anaerobic static titrations, and rapid kinetics analysis of wild-type enzyme and variants involving the His-509-Glu-514 dyad as the presumed acid-base catalyst. The dyad is conserved in all members of the enzyme family. Substitution of His-509 with glutamine and Glu-514 with alanine led to TrxR with only 0.5 and 7% of wild type activity, respectively, thus demonstrating the crucial roles of these residues for enzymatic activity. The H509Q variant had rate constants in both the reductive and oxidative half-reactions that were dramatically less than those of wild-type enzyme, and no thiolateflavin charge-transfer complex was observed. Glu-514 was shown to be involved in dithiol-disulfide interchange between the Cys-88/Cys-93 and Cys-535/Cys-540 pairs. In addition, Glu-514 appears to greatly enhance the role of His-509 in acid-base catalysis. It can be concluded that the His-509-Glu-514 dyad, in analogy to those in related oxidoreductases, acts as the acid-base catalyst in PfTrxR.

  3. Radiologist Evaluation of an X-ray Tube Based Diffraction Enhanced Imaging Prototype Using Full Thickness Breast Specimens.

    SciTech Connect

    Faulconer, L.; Zhong, Z.; Parham, C.; Connor, D. M.; , Kim, E.; Zeng, D.; Livasy, C.; Cole, E.; Kuzmiak, C.; Koomen, M.; Pavic, D.; Pisano, E.

    2009-05-21

    Conventional mammographic image contrast is derived from x-ray absorption, resulting in breast structure visualization due to density gradients that attenuate radiation without distinction between transmitted, scattered, or refracted x-rays. Diffraction-enhanced imaging (DEI) allows for increased contrast with decreased radiation dose compared to conventional mammographic imaging because of monochromatic x-rays, its unique refraction-based contrast mechanism, and excellent scatter rejection. However, a lingering drawback to the clinical translation of DEI has been the requirement for synchrotron radiation. The authors laboratory developed a DEI prototype (DEI-PR) using a readily available tungsten x-ray tube source and traditional DEI crystal optics, providing soft tissue images at 60 keV. Images of full-thickness human breast tissue specimens were acquired on synchrotron-based DEI (DEI-SR), DEI-PR, and digital mammographic systems. A panel of expert radiologists evaluated lesion feature visibility and correlation with pathology after receiving training on the interpretation of refraction contrast mammographic images. For mammographic features (mass, calcification), no significant differences were detected between the DEI-SR and DEI-PR systems. Benign lesions were perceived as better seen by radiologists using the DEI-SR system than the DEI-PR system at the [111] reflectivity, with generalizations limited by small sample size. No significant differences between DEI-SR and DEI-PR were detected for any other lesion type (atypical, cancer) at either crystal reflectivity. Thus, except for benign lesion characterizations, the DEI-PR system's performance was roughly equivalent to that of the traditional DEI system, demonstrating a significant step toward clinical translation of this modality for breast cancer applications.

  4. Rainfall-induced removal of copper-based spray residues from vines.

    PubMed

    Pérez-Rodríguez, P; Soto-Gómez, D; De La Calle, I; López-Periago, J E; Paradelo, M

    2016-10-01

    The continuous use of copper against fungal diseases and off-target effects causes major environmental and agronomic problems. However, the rain-induced removal of Cu-based residues is known only for a limited number of crops. We present the results of rain-induced removal of fungicides from two monitored vineyard plots which were sprayed with two widely used Cu-based formulations: copper-oxychloride (CO) and Bordeaux mixture (BM), respectively. Cu removal per growing season was 0.60±0.12kgha(-1) (30% of the applied fungicide) for CO and 0.80±0.10kgha(-1) for BM (70% of the applied fungicide). Fractioning the Cu in soluble (CuS) and particulate fractions (CuP) showed that most of the Cu was removed as CuP, but CuS concentrations found in throughfall collectors exceeded the regulatory threshold for toxicity in surface waters. The first few millimeters of rain caused most of the Cu removal. Our findings agreed with the data reported in the scientific literature, in which a significant fraction of the Cu-based formulation is loosely attached to the plant surfaces. In addition, we found that rainfall energy had a minor influence on the removal. PMID:27344398

  5. A direct competitive assay-based aptasensor for sensitive determination of tetracycline residue in honey.

    PubMed

    Wang, Sai; Liu, Jiahui; Yong, Wei; Chen, Qilong; Zhang, Liya; Dong, Yiyang; Su, Haijia; Tan, Tianwei

    2015-01-01

    Tetracycline (TC) is a common antibacterial agent used for prevention and control of animal diseases. The increasing concern about TC residue in food demands high-performing analytical techniques for food quality assessment. Biosensors represent a promising tool for food safety analysis as they can fulfill some demand that the conventional methods do not attain. In this study, a novel colorimetric aptasensor was developed for sensitive detection of TC in honey. The aptasensor was based on a modified direct competitive enzyme-linked aptamer assay (dc-ELAA) scheme utilizing a 76 mer single-stranded DNA (ssDNA) aptamer selected by Systematic Evolution of Ligands by Exponential Enrichment (SELEX). The optimized aptasensor showed a good limit of detection (LOD of 0.0978 ng/mL), a wide linear range (0.1-1000 ng/mL) toward TC in honey, with good recoveries (92.09-109.7%) in TC-spiked honey, and was compared with an indirect competitive assay-based aptasensor and validated with a standard ELISA. The biosensor based on dc-ELAA with good limit of detection and simplicity can be applied for high-throughput detection of TC in food. PMID:25281141

  6. Rainfall-induced removal of copper-based spray residues from vines.

    PubMed

    Pérez-Rodríguez, P; Soto-Gómez, D; De La Calle, I; López-Periago, J E; Paradelo, M

    2016-10-01

    The continuous use of copper against fungal diseases and off-target effects causes major environmental and agronomic problems. However, the rain-induced removal of Cu-based residues is known only for a limited number of crops. We present the results of rain-induced removal of fungicides from two monitored vineyard plots which were sprayed with two widely used Cu-based formulations: copper-oxychloride (CO) and Bordeaux mixture (BM), respectively. Cu removal per growing season was 0.60±0.12kgha(-1) (30% of the applied fungicide) for CO and 0.80±0.10kgha(-1) for BM (70% of the applied fungicide). Fractioning the Cu in soluble (CuS) and particulate fractions (CuP) showed that most of the Cu was removed as CuP, but CuS concentrations found in throughfall collectors exceeded the regulatory threshold for toxicity in surface waters. The first few millimeters of rain caused most of the Cu removal. Our findings agreed with the data reported in the scientific literature, in which a significant fraction of the Cu-based formulation is loosely attached to the plant surfaces. In addition, we found that rainfall energy had a minor influence on the removal.

  7. Development of risk-based computer models for deriving criteria on residual radioactivity and recycling

    SciTech Connect

    Chen, S.Y.

    1994-12-31

    Argonne National Laboratory (ANL) is developing multimedia environmental pathway and health risk computer models to assess radiological risks to human health and to derive cleanup guidelines for environmental restoration, decommissioning, and recycling activities. These models are based on the existing RESRAD code, although each has a separate design and serves different objectives. Two such codes are RESRAD-BUILD and RESRAD-PROBABILISTIC. The RESRAD code was originally developed to implement the US Department of Energy`s (DOE`s) residual radioactive materials guidelines for contaminated soils. RESRAD has been successfully used by DOE and its contractors to assess health risks and develop cleanup criteria for several sites selected for cleanup or restoration programs. RESRAD-BUILD analyzes human health risks from radioactive releases during decommissioning or rehabilitation of contaminated buildings. Risks to workers are assessed for dismantling activities; risks to the public are assessed for occupancy. RESRAD-BUILD is based on a room compartmental model analyzing the effects on room air quality of contaminant emission and resuspension (as well as radon emanation), the external radiation pathway, and other exposure pathways. RESRAD-PROBABILISTIC, currently under development, is intended to perform uncertainty analysis for RESRAD by using the Monte Carlo approach based on the Latin-Hypercube sampling scheme. The codes being developed at ANL are tailored to meet a specific objective of human health risk assessment and require specific parameter definition and data gathering. The combined capabilities of these codes satisfy various risk assessment requirements in environmental restoration and remediation activities.

  8. Experimental modules covering imaging, diffraction, Fourier optics and polarization based on a liquid-crystal cell SLM

    NASA Astrophysics Data System (ADS)

    Hermerschmidt, Andreas

    2009-06-01

    In close collaboration with four German universities, we have developed tutorials for experiments based on a transmissive liquid-crystal spatial light modulator (SLM). The experimental tutorials are grouped in six project modules, which cover a wide range of phenomena and have different levels of difficulty. At a basic level, students can investigate the SLM in its probably most well-known application as an image-generating element in a simple optical projector setup. At more advanced levels, the application as an adaptive optical element can be investigated in three different projects covering wave-optical phenomena. The fields covered include Fourier Optics using the SLM as a dynamic fan-out beam-splitter or kinoform, Computer-Generated Holography and basic Interferometry. For the support of these projects, software was developed which permits the generation of adaptive optical structures by the student with a user-friendly interface, while the underlying algorithms are explained in the theoretical tutorial. The modulation of the light by the twisted-neumatic liquid crystal cells of the SLM can be investigated in the two most advanced projects. In the first one, the parameters of the cell and the components of its Jones matrix can be derived from transmission measurements with rotatable polarizers at a number of different wavelengths. This project gives insight to the Jones matrix calculus at the level required for the analysis. In the second one, the complex-valued transmission of the SLM is determined by measuring the diffraction efficiency of dynamically addressed Ronchi gratings.

  9. Observation of optical second-harmonic generation in porous-silicon-based photonic crystals in the Laue diffraction scheme

    NASA Astrophysics Data System (ADS)

    Kopylov, D. A.; Svyakhovskiy, S. E.; Dergacheva, L. V.; Bushuev, V. A.; Mantsyzov, B. I.; Murzina, T. V.

    2016-05-01

    Second-harmonic generation (SHG) in the Laue scheme of the dynamical Bragg diffraction in one-dimensional photonic crystal (PhC) is studied. The experiments are performed for partially annealed porous-silicon PhC containing 250 periods of the structure. Our measurements confirm that the phase-matched optical SHG is observed under the Bragg conditions, which is evidenced by a narrow angular and spectral distribution of the diffracted SHG outgoing the PhC. This is confirmed by both the analytical description of the SHG process performed in the two-wave approximation, and by direct calculations of the PhC dispersion curves for the fundamental and SHG wavelengths by the revised plane wave method. Possible types of phase- and quasi-phase-matching realized in the studied PhC under the Laue diffraction scheme are discussed.

  10. Individual speckle diffraction based 1D and 2D Random Grating Fabrication for detector and solar energy harvesting applications

    PubMed Central

    Bingi, Jayachandra; Murukeshan, Vadakke Matham

    2016-01-01

    Laser speckles and speckle patterns, which are formed by the random interference of scattered waves from optically rough surfaces, have found tremendous applications in a wide range of metrological and biomedical fields. Here, we demonstrate a novel edge diffraction phenomenon of individual speckle for the fabrication of 1D and 2D micron and sub-micron size random gratings. These random gratings exhibit broadband response with interesting diffusive diffraction patterns. As an immediate application for solar energy harvesting, significant reduction in transmission and enhanced absorption in thin “Si-random grating-Si” sandwich structure is demonstrated. This work has multifaceted significance where we exploited the individual speckle diffraction properties for the first time. Besides the solar harvesting applications, random gratings are suitable structures for fabrication of theoretically proposed random quantum well IR detectors and hence expected that this work will augur well for such studies in the near future. PMID:26842242

  11. Identification of an ideal-like fingerprint for a protein fold using overlapped conserved residues based approach.

    PubMed

    Goyal, Amit; Sokalingam, Sriram; Hwang, Kyu-Suk; Lee, Sun-Gu

    2014-07-10

    Design of an efficient fingerprint that detects homologous proteins at distant sequence identity has been a great challenge. This paper proposes a strategy to extract an ideal-like fingerprint with high specificity and sensitivity from a group of sequences related to a fold. The approach is devised based on the assumptions that the critical residues for a protein fold may be conserved in three aspects, i.e. sequence, structure, and intramolecular interaction, and embedded in secondary structures. We hypothesized that the residues satisfying such conditions simultaneously may work as an efficient fingerprint. This idea was tested on protein folds of various classes, such as beta-strand rich, alpha + beta proteins and alpha/beta proteins with discrete sequence similarities. The fingerprint for each fold was generated by selecting the overlapped conserved residues (OCR) from the conserved residues obtained using independent three alignment methods, i.e. multiple sequence alignment, structure-based alignment, and alignment based on the interstrand hydrogen-bonds. The OCR fingerprints showed more than 90% detection efficiency for all the folds tested and were identified to be almost the minimal fingerprints composed of only critical residues. This study is expected to provide an important conceptual improvement in the identification or design of ideal fingerprints for a protein fold.

  12. Failure of Anisotropic Unstructured Mesh Adaption Based on Multidimensional Residual Minimization

    NASA Technical Reports Server (NTRS)

    Wood, William A.; Kleb, William L.

    2003-01-01

    An automated anisotropic unstructured mesh adaptation strategy is proposed, implemented, and assessed for the discretization of viscous flows. The adaption criteria is based upon the minimization of the residual fluctuations of a multidimensional upwind viscous flow solver. For scalar advection, this adaption strategy has been shown to use fewer grid points than gradient based adaption, naturally aligning mesh edges with discontinuities and characteristic lines. The adaption utilizes a compact stencil and is local in scope, with four fundamental operations: point insertion, point deletion, edge swapping, and nodal displacement. Evaluation of the solution-adaptive strategy is performed for a two-dimensional blunt body laminar wind tunnel case at Mach 10. The results demonstrate that the strategy suffers from a lack of robustness, particularly with regard to alignment of the bow shock in the vicinity of the stagnation streamline. In general, constraining the adaption to such a degree as to maintain robustness results in negligible improvement to the solution. Because the present method fails to consistently or significantly improve the flow solution, it is rejected in favor of simple uniform mesh refinement.

  13. Comparison of metals extractability from Al/Fe-based drinking water treatment residuals.

    PubMed

    Wang, Changhui; Bai, Leilei; Pei, Yuansheng; Wendling, Laura A

    2014-12-01

    Recycling of drinking water treatment residuals (WTRs) as environment amendments has attracted substantial interest due to their productive reuse concomitant with waste minimization. In the present study, the extractability of metals within six Al/Fe-hydroxide-comprised WTRs collected throughout China was investigated using fractionation, in vitro digestion and the toxicity characteristic leaching procedure (TCLP). The results suggested that the major components and structure of the WTRs investigated were similar. The WTRs were enriched in Al, Fe, Ca, and Mg, also contained varying quantities of As, Ba, Be, Cd, Co, Cr, Cu, K, Mn, Mo, Na, Ni, Pb, Sr, V, and Zn, but Ag, Hg, Sb, and Se were not detected. Most of the metals within the WTRs were largely non-extractable using the European Community Bureau of Reference (BCR) procedure, but many metals exhibited high bioaccessibility based on in vitro digestion. However, the WTRs could be classified as non-hazardous according to the TCLP assessment method used by the US Environmental Protection Agency (USEPA). Further analysis showed the communication factor, which is calculated as the ratio of total extractable metal by BCR procedure to the total metal, for most metals in the six WTRs, was similar, whereas the factor for Ba, Mn, Sr, and Zn varied substantially. Moreover, metals in the WTRs investigated had different risk assessment code. In summary, recycling of WTRs is subject to regulation based on assessment of risk due to metals prior to practical application.

  14. Comparison of metals extractability from Al/Fe-based drinking water treatment residuals.

    PubMed

    Wang, Changhui; Bai, Leilei; Pei, Yuansheng; Wendling, Laura A

    2014-12-01

    Recycling of drinking water treatment residuals (WTRs) as environment amendments has attracted substantial interest due to their productive reuse concomitant with waste minimization. In the present study, the extractability of metals within six Al/Fe-hydroxide-comprised WTRs collected throughout China was investigated using fractionation, in vitro digestion and the toxicity characteristic leaching procedure (TCLP). The results suggested that the major components and structure of the WTRs investigated were similar. The WTRs were enriched in Al, Fe, Ca, and Mg, also contained varying quantities of As, Ba, Be, Cd, Co, Cr, Cu, K, Mn, Mo, Na, Ni, Pb, Sr, V, and Zn, but Ag, Hg, Sb, and Se were not detected. Most of the metals within the WTRs were largely non-extractable using the European Community Bureau of Reference (BCR) procedure, but many metals exhibited high bioaccessibility based on in vitro digestion. However, the WTRs could be classified as non-hazardous according to the TCLP assessment method used by the US Environmental Protection Agency (USEPA). Further analysis showed the communication factor, which is calculated as the ratio of total extractable metal by BCR procedure to the total metal, for most metals in the six WTRs, was similar, whereas the factor for Ba, Mn, Sr, and Zn varied substantially. Moreover, metals in the WTRs investigated had different risk assessment code. In summary, recycling of WTRs is subject to regulation based on assessment of risk due to metals prior to practical application. PMID:25023656

  15. Prediction of Residual Stress Distributions in Welded Sections of P92 Pipes with Small Diameter and Thick Wall based on 3D Finite Element Simulation

    NASA Astrophysics Data System (ADS)

    Wang, Xiaowei; Gong, Jianming; Zhao, Yanping; Wang, Yanfei

    2015-05-01

    This study used ABAQUS finite element (FE) software to investigate the residual stress distributions of P92 welded pipes in both the as-weld and post weld heat treated (PWHT) condition. Sequential coupling quasi-static thermo-mechanical in conjunction with moving double ellipsoidal heat source and an element add/remove technique to simulate deposition of new weld material, are combined in the 3D FE analysis. To validate the simulation results, the residual stresses in axial direction at the surface of pipe were measured by X-ray diffraction technique and compared with the results of FE analysis. Detailed characteristic distributions of the residual stresses are discussed. Results show that the FE model can predict the residual stress distributions satisfactorily. Highest residual stresses on the outer surface are found in the last weld bead to be deposited. And the highest tensile residual stress for the full welded section take place in heat affected zone (HAZ) near the middle thickness. Larger residual sstress can be found around the welding start point along the pipe circumference. Comparison of heat treated specimen and untreated specimen illustrates that PWHT has a strong effect on the residual stress field.

  16. [Quantification of crop residue burned areas based on burning indices using Landsat 8 image].

    PubMed

    Ma, Jian-hang; Song, Kai-shar; Wen, Zhi-dan; Shao, Tian-tian; Li, Bo-nan; Qi, Cai

    2015-11-01

    Crop residue burning leads to atmospheric pollution and is an enormous waste of crop residue resource. Crop residue burning can be monitored timely in large regions as the fire points can be recognized through remotely sensed image via thermal infrared bands. However, the area, the detailed distribution pattern and especially the severity of the burning areas cannot be derived only by the thermal remote sensing approach. The burning index, which was calculated with two or more spectral bands at where the burned and unburned areas have distinct spectral characteristics, is widely used in the forest fire investigation. However its potential application for crop residue burning evaluation has not been explored. With two Landsat 8 images that cover a part of the Songnen Plain, three burning indices, i.e., the normalized burned ratio (NBR), the normalized burned ratio incorporating the thermal band (NBRT), and the burned area index (BAI), were used to classify the crop residue burned and unburned areas. The overall classification accuracies were 91.9%, 92.3%, and 87.8%, respectively. The correlation analysis between the indices and the crop residue coverage indicated that the NBR and NBRT were positively correlated with the crop residue coverage (R2 = 0.73 and 0.64, respectively) with linear regression models, while the BAI was exponentially correlated with the crop residue coverage (R2 = 0.68). The results indicated that the use of burning indices in crop residue burning monitoring could quantify crop residue burning severity and provide valuable data for evaluating atmospheric pollution.

  17. [Quantification of crop residue burned areas based on burning indices using Landsat 8 image].

    PubMed

    Ma, Jian-hang; Song, Kai-shar; Wen, Zhi-dan; Shao, Tian-tian; Li, Bo-nan; Qi, Cai

    2015-11-01

    Crop residue burning leads to atmospheric pollution and is an enormous waste of crop residue resource. Crop residue burning can be monitored timely in large regions as the fire points can be recognized through remotely sensed image via thermal infrared bands. However, the area, the detailed distribution pattern and especially the severity of the burning areas cannot be derived only by the thermal remote sensing approach. The burning index, which was calculated with two or more spectral bands at where the burned and unburned areas have distinct spectral characteristics, is widely used in the forest fire investigation. However its potential application for crop residue burning evaluation has not been explored. With two Landsat 8 images that cover a part of the Songnen Plain, three burning indices, i.e., the normalized burned ratio (NBR), the normalized burned ratio incorporating the thermal band (NBRT), and the burned area index (BAI), were used to classify the crop residue burned and unburned areas. The overall classification accuracies were 91.9%, 92.3%, and 87.8%, respectively. The correlation analysis between the indices and the crop residue coverage indicated that the NBR and NBRT were positively correlated with the crop residue coverage (R2 = 0.73 and 0.64, respectively) with linear regression models, while the BAI was exponentially correlated with the crop residue coverage (R2 = 0.68). The results indicated that the use of burning indices in crop residue burning monitoring could quantify crop residue burning severity and provide valuable data for evaluating atmospheric pollution. PMID:26915202

  18. Likelihood- and residual-based evaluation of medium-term earthquake forecast models for California

    NASA Astrophysics Data System (ADS)

    Schneider, Max; Clements, Robert; Rhoades, David; Schorlemmer, Danijel

    2014-09-01

    Seven competing models for forecasting medium-term earthquake rates in California are quantitatively evaluated using the framework of the Collaboratory for the Study of Earthquake Predictability (CSEP). The model class consists of contrasting versions of the Every Earthquake a Precursor According to Size (EEPAS) and Proximity to Past Earthquakes (PPE) modelling approaches. Models are ranked by their performance on likelihood-based tests, which measure the consistency between a model forecast and observed earthquakes. To directly compare one model against another, we run a classical paired t-test and its non-parametric alternative on an information gain score based on the forecasts. These test scores are complemented by several residual-based methods, which offer detailed spatial information. The experiment period covers 2009 June-2012 September, when California experienced 23 earthquakes above the magnitude threshold. Though all models fail to capture seismicity during an earthquake sequence, spatio-temporal differences between models also emerge. The overall best-performing model has strong time- and magnitude-dependence, weights all earthquakes equally as medium-term precursors of larger events and has a full set of fitted parameters. Models with this time- and magnitude-dependence offer a statistically significant advantage over simpler baseline models. In addition, models that down-weight aftershocks when forecasting larger events have a desirable feature in that they do not overpredict following an observed earthquake sequence. This tendency towards overprediction differs between the simpler model, which is based on fewer parameters, and more complex models that include more parameters.

  19. SVM based prediction of RNA-binding proteins using binding residues and evolutionary information.

    PubMed

    Kumar, Manish; Gromiha, M Michael; Raghava, Gajendra P S

    2011-01-01

    RNA-binding proteins (RBPs) play crucial role in transcription and gene-regulation. This paper describes a support vector machine (SVM) based method for discriminating and classifying RNA-binding and non-binding proteins using sequence features. With the threshold of 30% interacting residues, RNA-binding amino acid prediction method PPRINT achieved the Matthews correlation coefficient (MCC) of 0.32. BLAST and PSI-BLAST identified RBPs with the coverage of 32.63 and 33.16%, respectively, at the e-value of 1e-4. The SVM models developed with amino acid, dipeptide and four-part amino acid compositions showed the MCC of 0.60, 0.46, and 0.53, respectively. This is the first study in which evolutionary information in form of position specific scoring matrix (PSSM) profile has been successfully used for predicting RBPs. We achieved the maximum MCC of 0.62 using SVM model based on PSSM called PSSM-400. Finally, we developed different hybrid approaches and achieved maximum MCC of 0.66. We also developed a method for predicting three subclasses of RNA binding proteins (e.g., rRNA, tRNA, mRNA binding proteins). The performance of the method was also evaluated on an independent dataset of 69 RBPs and 100 non-RBPs (NBPs). An additional benchmarking was also performed using gene ontology (GO) based annotation. Based on the hybrid approach a web-server RNApred has been developed for predicting RNA binding proteins from amino acid sequences (http://www.imtech.res.in/raghava/rnapred/).

  20. Diffractive dijet and W production in CDF

    SciTech Connect

    Goulianos, K.

    1998-06-01

    Results on diffractive dijet and W-boson production from CDF are reviewed and compared with predictions based on factorization of the diffractive structure function of the proton measured in deep inelastic scattering at HERA.

  1. Estimation of the residual life of steam-turbine condensers based on statistical models

    NASA Astrophysics Data System (ADS)

    Murmansky, B. E.; Aronson, K. E.; Brodov, Yu. M.

    2015-11-01

    The article presents the results of a study aimed at estimation of the state and prediction of the residual life of steam-turbine condensers on the basis of statistical analysis. The possibility of such evaluation during the operation of steam-turbine plants with accuracy sufficient for practical purposes is demonstrated. It is shown that identification of the operating period, viz., the initial period, the normal operation period, or the period of the lifetime exhaustion, as well as determination of the condenser's operating time at the moment when the failure of an individual tube occurs, is very important for statistical evaluation of the condenser state. Two statistical models are proposed and comparative analysis of the results calculated by these models for the residual life of the condensers at the Reftinskaya SDPP has been performed. The first model can be used when comprehensive information about the condenser's operating time before the tubes have failed is available as well as a priori information—or information based on analysis of the condenser tube metal—that the condenser is in its normal operation period. In this case, the fact of exhaustion of the condenser's lifetime is established by reaching the limit of the failed condenser tubes, which is determined by technical and economic analysis of losses caused by operating the turbine with a reduced heat-exchange surface of the condenser. The distribution function for the operating time of the failed tubes is approximated by a normal distribution. In the cases when no precise information on the condenser tubes' operating time is available at the thermoelectric power plant (TEPP), the second statistical model based on censored samples is proposed for estimation of the condenser state. An expression to assess the confidence interval that determines the significant difference between the distribution functions for complete and censored operating time values has been derived. It is shown that this model

  2. Experimental determination of residual stress

    NASA Technical Reports Server (NTRS)

    Ferguson, Milton W.

    1991-01-01

    Residual stresses in finished parts have often been regarded as factors contributing to premature part failure and geometric distortions. Currently, residual stresses in welded structures and railroad components are being investigated. High residual stresses formed in welded structures due primarily to the differential contractions of the weld material as it cools and solidifies can have a profound effect on the surface performance of the structure. In railroad wheels, repeated use of the brakes causes high residual stresses in the rims which may lead to wheel failure and possible derailment. The goals of the study were: (1) to develop strategies for using x-ray diffraction to measure residual stress; (2) to subject samples of Inconel 718 to various mechanical and heat treatments and to measure the resulting stress using x-ray diffraction; and (3) to measure residual stresses in ferromagnetic alloys using magnetoacoustics.

  3. Apparatus and fast method for cancer cell classification based on high harmonic coherent diffraction imaging in reflection geometry

    NASA Astrophysics Data System (ADS)

    Zürch, Michael; Foertsch, Stefan; Matzas, Mark; Pachmann, Katharina; Kuth, Rainer; Spielmann, Christian

    2014-03-01

    In cancer treatment it is highly desirable to identify and /or classify individual cancer cells in real time. Nowadays, the standard method is PCR which is costly and time-consuming. Here we present a different approach to rapidly classify cell types: we measure the pattern of coherently diffracted extreme ultraviolet radiation (XUV radiation at 38nm wavelength), allowing to distinguish different single breast cancer cell types. The output of our laser driven XUV light source is focused onto a single unstained and unlabeled cancer cell, and the resulting diffraction pattern is measured in reflection geometry. As we will further show, the outer shape of the object can be retrieved from the diffraction pattern with sub-micron resolution. For classification it is often not necessary to retrieve the image, it is only necessary to compare the diffraction patterns which can be regarded as a spatial fingerprint of the specimen. For a proof-of-principle experiment MCF7 and SKBR3 breast cancer cells were pipetted on gold-coated silica slides. From illuminating each single cell and measuring a diffraction pattern we could distinguish between them. Owing to the short bursts of coherent soft x-ray light, one could also image temporal changes of the specimen, i.e. studying changes upon drug application once the desired specimen is found by the classification method. Using a more powerful laser, even classifying circulating tumor cells (CTC) at a high throughput seems possible. This lab-sized equipment will allow fast classification of any kind of cells, bacteria or even viruses in the near future.

  4. Fast digestion procedure for determination of catalyst residues in La- and Ni-based carbon nanotubes.

    PubMed

    Mortari, Sergio Roberto; Cocco, Carmem Regina; Bartz, Fabiane Regina; Dresssler, Valderi L; Flores, Erico Marlon de Moraes

    2010-05-15

    A procedure based on microwave-induced combustion (MIC) was applied for carbon nanotube (CNT) digestion and further determination of La and Ni by inductively coupled plasma optical emission spectrometry (ICP OES). Samples (up to 400 mg) were completely combusted at 20 bar of oxygen, and a reflux step was applied to improve the analyte absorption. Combustion was finished in less than 50 s, and analytes were absorbed in diluted acid solution. Absorbing solutions ranging from 1 to 12 mol L(-1) for HCl and from 1 to 14 mol L(-1) HNO(3) were tested. Accuracy for both analytes was evaluated using certified reference materials and analyte spikes. Neutron activation analysis was also used to check accuracy for La. Agreement was better than 96% for La and Ni using a 4 mol L(-1) absorbing solution of HNO(3) or HCl and 15 min of reflux. The residual carbon content was lower than 0.5%. Up to eight samples could be digested simultaneously in 36 min, that makes the throughput using MIC more suitable when it is compared to the digestion by dry ashing as recommended by other procedures. The obtained limits of detection using MIC were lower than those using dry ashing, and a single absorbing solution, e.g., diluted HNO(3), can be used for simultaneous determination of La and Ni by ICP OES. PMID:20405950

  5. Thermogravimetric kinetic study of agricultural residue biomass pyrolysis based on combined kinetics.

    PubMed

    Wang, Xun; Hu, Mian; Hu, Wanyong; Chen, Zhihua; Liu, Shiming; Hu, Zhiquan; Xiao, Bo

    2016-11-01

    Pyrolytic kinetic of an agricultural residue (AR) feedstock, a mixture of plants (cotton, wheat, rich, corn) stems, was investigated based on combined kinetics. The most suitable mechanism for AR one-step pyrolysis was f(α)=(1-α)(1.1816)α(-1.8428) with kinetic parameters of: apparent activation energy 221.7kJ/mol, pre-exponential factor 4.17E16s(-1). Pyrolysis of AR feedstock could not be described by one-step reaction attributes to heterogeneous features of pyrolysis processes. Combined kinetics three-parallel-reaction (CK-TPR) model fitted the pyrolysis experimental data very well. Reaction mechanisms for pseudo hemicelluloses, cellulose, lignin in CK-TPR model was f(α)=(1-α)(1.6244)α(-0.3371)[-ln(1-α)](-0.0515), f(α)=(1-α)(1.0597)α(-0.6909)[-ln(1-α)](0.9026) and f(α)=(1-α)(2.9577)α(-4.7719), respectively. Apparent activation energy of three pseudo components followed the order of Elignin(197.3kJ/mol)>Ecellulose(176.3kJ/mol)>Ehemicelluloses (151.1kJ/mol). Mechanism of hemicelluloses pyrolysis could be further expressed as f(α)=(1-α)(1.4). The pyrolytic mechanism of cellulose met the Nucleation well. However, mechanism of lignin pyrolysis was complex, which possibly was the combined effects of Nucleation, Diffusion, Geometrical contraction, and Power law.

  6. Characterization of activated carbon prepared from chlorella-based algal residue.

    PubMed

    Chang, Yuan-Ming; Tsai, Wen-Tien; Li, Ming-Hsuan

    2015-05-01

    The chlorella-based microalgal residue (AR) was tested as a novel precursor for preparing activated carbons. A combined carbonization-activation process with flowing N2 and CO2 gases was used to prepare the carbon materials at the activation temperatures of 800-1000 °C and the residence times of 0-30 min in this work. The elemental contents, pore properties and scanning electron microscopy (SEM) observations of the resulting activated carbons have been performed. The results showed that activation temperature may be the most important parameter for determining their pore properties. The maximal Brunauer-Emmett-Teller (BET) surface area and total pore volume of the resulting activated carbon, which was produced at the activation temperature of 950 °C with the residence time of 30 min, were 840 m(2)/g and 0.46 cm(3)/g, respectively. More interestingly, the resulting activated carbons have significant nitrogen contents of 3.6-9.6 wt%, which make them lower carbon contents (i.e., 54.6-68.4 wt%) than those of commercial activated carbons.

  7. Thermogravimetric kinetic study of agricultural residue biomass pyrolysis based on combined kinetics.

    PubMed

    Wang, Xun; Hu, Mian; Hu, Wanyong; Chen, Zhihua; Liu, Shiming; Hu, Zhiquan; Xiao, Bo

    2016-11-01

    Pyrolytic kinetic of an agricultural residue (AR) feedstock, a mixture of plants (cotton, wheat, rich, corn) stems, was investigated based on combined kinetics. The most suitable mechanism for AR one-step pyrolysis was f(α)=(1-α)(1.1816)α(-1.8428) with kinetic parameters of: apparent activation energy 221.7kJ/mol, pre-exponential factor 4.17E16s(-1). Pyrolysis of AR feedstock could not be described by one-step reaction attributes to heterogeneous features of pyrolysis processes. Combined kinetics three-parallel-reaction (CK-TPR) model fitted the pyrolysis experimental data very well. Reaction mechanisms for pseudo hemicelluloses, cellulose, lignin in CK-TPR model was f(α)=(1-α)(1.6244)α(-0.3371)[-ln(1-α)](-0.0515), f(α)=(1-α)(1.0597)α(-0.6909)[-ln(1-α)](0.9026) and f(α)=(1-α)(2.9577)α(-4.7719), respectively. Apparent activation energy of three pseudo components followed the order of Elignin(197.3kJ/mol)>Ecellulose(176.3kJ/mol)>Ehemicelluloses (151.1kJ/mol). Mechanism of hemicelluloses pyrolysis could be further expressed as f(α)=(1-α)(1.4). The pyrolytic mechanism of cellulose met the Nucleation well. However, mechanism of lignin pyrolysis was complex, which possibly was the combined effects of Nucleation, Diffusion, Geometrical contraction, and Power law. PMID:27521788

  8. Slaking characteristics of unsaturated granite residual soils based on a modified slaking test method

    NASA Astrophysics Data System (ADS)

    Zhang, S.

    2012-12-01

    Slaking is one of the distinct process involved in the structural breakdown that occurs when soils are suddenly immersed in, or placed in contact with, water. The process occurs because the tensile stress of soil skeleton cannot withstand the stresses caused by rapid water uptake. Some instability problems caused by slaking process were found on subway tunnels and engineered slopes excavated in granite residual soils (GRS) in Guangzhou, south China. A serious of experimental laboratory studies were carried out in order to get better understanding about the slaking characteristics of GRS. Unsaturated GRS samples with different initial moisture content and different degree of compaction were made for test using homemade apparatus. We proposed a modified slaking test mothod to obtain slaking curves so as to reflect the actual slaking process on the basis of experimental observation and mechanism analysis as much as possible. The method considerred air escape process during water uptaking which combined the two extremes involved in water uptaking with free escape of displaced air and with no air escape. Subsequently, a modified slaking velocity index based on the the slaking curve was calculated and utilized for further data processing and analysis. We discussed the relationship between two main control factors (fillable porosity of soil and initial matric suction of soil) and slaking velocity as well. The results reveal that it has exponential function relationship for fillable porosity of soil and logarithm function relationship for initial matric suction of soil.

  9. Active cancellation of residual amplitude modulation in a frequency-modulation based Fabry-Perot interferometer.

    PubMed

    Yu, Yinan; Wang, Yicheng; Pratt, Jon R

    2016-03-01

    Residual amplitude modulation (RAM) is one of the most common noise sources known to degrade the sensitivity of frequency modulation spectroscopy. RAM can arise as a result of the temperature dependent birefringence of the modulator crystal, which causes the orientation of the crystal's optical axis to shift with respect to the polarization of the incident light with temperature. In the fiber-based optical interferometer used on the National Institute of Standards and Technology calculable capacitor, RAM degrades the measured laser frequency stability and correlates with the environmental temperature fluctuations. We have demonstrated a simple approach that cancels out excessive RAM due to polarization mismatch between the light and the optical axis of the crystal. The approach allows us to measure the frequency noise of a heterodyne beat between two lasers individually locked to different resonant modes of a cavity with an accuracy better than 0.5 ppm, which meets the requirement to further determine the longitudinal mode number of the cavity length. Also, this approach has substantially mitigated the temperature dependency of the measurements of the cavity length and consequently the capacitance. PMID:27036752

  10. Active cancellation of residual amplitude modulation in a frequency-modulation based Fabry-Perot interferometer

    NASA Astrophysics Data System (ADS)

    Yu, Yinan; Wang, Yicheng; Pratt, Jon R.

    2016-03-01

    Residual amplitude modulation (RAM) is one of the most common noise sources known to degrade the sensitivity of frequency modulation spectroscopy. RAM can arise as a result of the temperature dependent birefringence of the modulator crystal, which causes the orientation of the crystal's optical axis to shift with respect to the polarization of the incident light with temperature. In the fiber-based optical interferometer used on the National Institute of Standards and Technology calculable capacitor, RAM degrades the measured laser frequency stability and correlates with the environmental temperature fluctuations. We have demonstrated a simple approach that cancels out excessive RAM due to polarization mismatch between the light and the optical axis of the crystal. The approach allows us to measure the frequency noise of a heterodyne beat between two lasers individually locked to different resonant modes of a cavity with an accuracy better than 0.5 ppm, which meets the requirement to further determine the longitudinal mode number of the cavity length. Also, this approach has substantially mitigated the temperature dependency of the measurements of the cavity length and consequently the capacitance.

  11. Conformation analysis of aspartame-based sweeteners by NMR spectroscopy, molecular dynamics simulations, and X-ray diffraction studies.

    PubMed

    De Capua, Antonia; Goodman, Murray; Amino, Yusuke; Saviano, Michele; Benedetti, Ettore

    2006-02-01

    We report here the synthesis and the conformation analysis by 1H NMR spectroscopy and computer simulations of six potent sweet molecules, N-[3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl]-alpha-L-aspartyl-S-tert-butyl-L-cysteine 1-methylester (1; 70 000 times more potent than sucrose), N-[3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl]-alpha-L-aspartyl-beta-cyclohexyl-L-alanine 1-methylester (2; 50 000 times more potent than sucrose), N-[3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl]-alpha-L-aspartyl-4-cyan-L-phenylalanine 1-methylester (3; 2 000 times more potent than sucrose), N-[3,3-dimethylbutyl]-alpha-L-aspartyl-(1R,2S,4S)-1-methyl-2-hydroxy-4-phenylhexylamide (4; 5500 times more potent than sucrose), N-[3-(3-hydroxy-4-methoxyphenyl)propyl]-alpha-L-aspartyl-(1R,2S,4S)-1-methyl-2-hydroxy-4-phenylhexylamide (5; 15 000 times more potent than sucrose), and N-[3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl]-alpha-L-aspartyl-(1R,2S,4S)-1-methyl-2-hydroxy-4-phenylhexylamide (6; 15 000 times more potent than sucrose). The "L-shaped" structure, which we believe to be responsible for sweet taste, is accessible to all six molecules in solution. This structure is characterized by a zwitterionic ring formed by the AH- and B-containing moieties located along the +y axis and by the hydrophobic group X pointing into the +x axis. Extended conformations with the AH- and B-containing moieties along the +y axis and the hydrophobic group X pointing into the -y axis were observed for all six sweeteners. For compound 5, the crystal-state conformation was also determined by an X-ray diffraction study. The result indicates that compound 5 adopts an L-shaped structure even in the crystalline state. The extraordinary potency of the N-arylalkylated or N-alkylated compounds 1-6, as compared with that of the unsubstituted aspartame-based sweet taste ligands, can be explained by the effect of a second hydrophobic binding domain in addition to interactions arising from the L-shaped structure. In our

  12. Development of a Neutron Diffraction Based Experiemental Capability for Investigating Hydraulic Fracturing for EGS-like Conditions

    SciTech Connect

    Polsky, Yarom; Anovitz, Lawrence {Larry} M; An, Ke; Carmichael, Justin R; Bingham, Philip R; Dessieux Jr, Luc Lucius

    2013-01-01

    Hydraulic fracturing to enhance formation permeability is an established practice in the Oil & Gas (O&G) industry and is expected to be an enabler for EGS. However, it is rarely employed in conventional geothermal systems and there are significant questions regarding the translation of practice from O&G to both conventional geothermal and EGS applications. Lithological differences(sedimentary versus crystalline rocks, significantly greater formation temperatures and different desired fracture characteristics are among a number of factors that are likely to result in a gap of understanding of how to manage hydraulic fracturing practice for geothermal. Whereas the O&G community has had both the capital and the opportunity to develop its understanding of hydraulic fracturing operations empirically in the field as well through extensive R&D efforts, field testing opportunities for EGS are likely to be minimal due to the high expense of hydraulic fracturing field trials. A significant portion of the knowledge needed to guide the management of geothermal/EGS hydraulic fracturing operations will therefore likely have to come from experimental efforts and simulation. This paper describes ongoing efforts at Oak Ridge National Laboratory (ORNL) to develop an experimental capability to map the internal stresses/strains in core samples subjected to triaxial stress states and temperatures representative of EGS-like conditions using neutron diffraction based strain mapping techniques. This capability is being developed at ORNL\\'s Spallation Neutron Source, the world\\'s most powerful pulsed neutron source and is still in a proof of concept phase. A specialized pressure cell has been developed that permits independent radial and axial fluid pressurization of core samples, with axial flow through capability and a temperature rating up to 300 degrees C. This cell will ultimately be used to hydraulically pressurize EGS-representative core samples to conditions of imminent fracture

  13. Conformation analysis of aspartame-based sweeteners by NMR spectroscopy, molecular dynamics simulations, and X-ray diffraction studies.

    PubMed

    De Capua, Antonia; Goodman, Murray; Amino, Yusuke; Saviano, Michele; Benedetti, Ettore

    2006-02-01

    We report here the synthesis and the conformation analysis by 1H NMR spectroscopy and computer simulations of six potent sweet molecules, N-[3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl]-alpha-L-aspartyl-S-tert-butyl-L-cysteine 1-methylester (1; 70 000 times more potent than sucrose), N-[3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl]-alpha-L-aspartyl-beta-cyclohexyl-L-alanine 1-methylester (2; 50 000 times more potent than sucrose), N-[3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl]-alpha-L-aspartyl-4-cyan-L-phenylalanine 1-methylester (3; 2 000 times more potent than sucrose), N-[3,3-dimethylbutyl]-alpha-L-aspartyl-(1R,2S,4S)-1-methyl-2-hydroxy-4-phenylhexylamide (4; 5500 times more potent than sucrose), N-[3-(3-hydroxy-4-methoxyphenyl)propyl]-alpha-L-aspartyl-(1R,2S,4S)-1-methyl-2-hydroxy-4-phenylhexylamide (5; 15 000 times more potent than sucrose), and N-[3-(3-hydroxy-4-methoxyphenyl)-3-methylbutyl]-alpha-L-aspartyl-(1R,2S,4S)-1-methyl-2-hydroxy-4-phenylhexylamide (6; 15 000 times more potent than sucrose). The "L-shaped" structure, which we believe to be responsible for sweet taste, is accessible to all six molecules in solution. This structure is characterized by a zwitterionic ring formed by the AH- and B-containing moieties located along the +y axis and by the hydrophobic group X pointing into the +x axis. Extended conformations with the AH- and B-containing moieties along the +y axis and the hydrophobic group X pointing into the -y axis were observed for all six sweeteners. For compound 5, the crystal-state conformation was also determined by an X-ray diffraction study. The result indicates that compound 5 adopts an L-shaped structure even in the crystalline state. The extraordinary potency of the N-arylalkylated or N-alkylated compounds 1-6, as compared with that of the unsubstituted aspartame-based sweet taste ligands, can be explained by the effect of a second hydrophobic binding domain in addition to interactions arising from the L-shaped structure. In our

  14. Fatigue-induced Reversible/Irreversible Structural-transformation Study of a Ni-based Superalloy Using Combined In-situ Neutron-Diffraction and Thermal Approaches

    SciTech Connect

    Huang, E-Wen; Barabash, Rozaliya; Clausen, Bjorn; Liu, Yee-Lang; Kai, Ji-Jung; Ice, Gene E; Woods, Kyle P.; Liaw, Peter K

    2010-01-01

    Cyclic loading and the subsequent fatigue damage have been investigated with the in-situ neutron-diffraction and thermal characterization for a single-phase, polycrystal nickel-based alloy. The lattice-strain evolution is compared with the bulk parameters, such as the applied stress and the thermal response as a function of the fatigue cycles. The in-situ neutron-diffraction and thermal-evolution results identify the development of the five fatigue-damage stages. Fatigue damage is observed with bulk hardening, softening, and eventual saturation evident in both the diffraction patterns and the thermal-evolution features. An increase in the dislocation density and the formation of the patterned-dislocation structure are responsible for hardening within the early cycles. With further cyclic loading, the rearrangements of the dislocations result in the cyclic softening. The transition to saturation cycles is characterized by the anisotropy of the lattice strain evolution. The nonmonotonic thermal response and the irreversible anisotropy of the lattice-strain evolution are observed in the final saturation fatigue cycles. The fatigue-damage microstructure and dislocation-substructure evolution are studied with diffraction-profile analyses and complemented by the transmission-electron microscopy. The fluctuations of the differential dislocation density and size of the patterned substructure along with the in-situ thermal measurements reveal a second-order-kind structural transition and indicate the development of the irreversible fatigue-induced microstructure.

  15. Evaluation of improved materials for stationary diesel engines operating on residual and coal based fuels. Final report

    SciTech Connect

    Not Available

    1980-01-01

    Experimental results to date from an on-going research program on improved materials for stationary diesel engines using residual or coal-based fuels are presented with little discussion of conclusions about these results. Information is included on ring and liner wear, fuel oil qualities, ceramic materials, coatings, test procedures and equipment, and tribology test results. (LCL)

  16. A sensitive monoclonal antibody-based enzyme-linked immunosorbent assay for chlorpyrifos residue determination in Chinese agricultural smaples

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A monoclonal antibody-based competitive antibody-coated enzyme-linked immunosorbent assay (ELISA) was developed and optimized for determining chlorpyrifos residue in agricultural products. The IC50 and IC10 of this ELISA were 3.3 ng/mL and 0.1 ng/mL respectively. The average recoveries recovery rate...

  17. An Image Segmentation Based on a Genetic Algorithm for Determining Soil Coverage by Crop Residues

    PubMed Central

    Ribeiro, Angela; Ranz, Juan; Burgos-Artizzu, Xavier P.; Pajares, Gonzalo; Sanchez del Arco, Maria J.; Navarrete, Luis

    2011-01-01

    Determination of the soil coverage by crop residues after ploughing is a fundamental element of Conservation Agriculture. This paper presents the application of genetic algorithms employed during the fine tuning of the segmentation process of a digital image with the aim of automatically quantifying the residue coverage. In other words, the objective is to achieve a segmentation that would permit the discrimination of the texture of the residue so that the output of the segmentation process is a binary image in which residue zones are isolated from the rest. The RGB images used come from a sample of images in which sections of terrain were photographed with a conventional camera positioned in zenith orientation atop a tripod. The images were taken outdoors under uncontrolled lighting conditions. Up to 92% similarity was achieved between the images obtained by the segmentation process proposed in this paper and the templates made by an elaborate manual tracing process. In addition to the proposed segmentation procedure and the fine tuning procedure that was developed, a global quantification of the soil coverage by residues for the sampled area was achieved that differed by only 0.85% from the quantification obtained using template images. Moreover, the proposed method does not depend on the type of residue present in the image. The study was conducted at the experimental farm “El Encín” in Alcalá de Henares (Madrid, Spain). PMID:22163966

  18. Formation of a periodic diffractive structure based on poly(methyl methacrylate) with ion-implanted silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Galyautdinov, M. F.; Nuzhdin, V. I.; Fattakhov, Ya. V.; Farrakhov, B. F.; Valeev, V. F.; Osin, Yu. N.; Stepanov, A. L.

    2016-02-01

    We propose to form optical diffractive elements on the surface of poly(methyl methacrylate) (PMMA) by implanting the polymer with silver ions ( E = 30 keV; D = 5.0 × 1014 to 1.5 × 1017 ion/cm2; I = 2 μA/cm2) through a nickel grid (mask). Ion implantation leads to the nucleation and growth of silver nanoparticles in unmasked regions of the polymer. The formation of periodic surface microstructures during local sputtering of the polymer by incident ions was monitored using an optical microscope. The diffraction efficiency of obtained gratings is demonstrated under conditions of their probing with semiconductor laser radiation in the visible spectral range.

  19. Vectorial algorithm for the computation of light propagation equation based on Huygens' principle using the scalar theory of diffraction

    NASA Astrophysics Data System (ADS)

    Morucci, Stephane; Noirard, Pierre; Grossetie, Jean-Claude

    1996-03-01

    In digital holography, computation of holograms is often reduced to calculations of fast Fourier transforms if the distance between the object plane and the hologram plane is large enough. Two classical approximations for solving this problem include a binomial series expansion of the distance and an elimination of the so-called inclination factor. We present here a vectorial algorithm which computes the discrete form of the light propagation equation obtained by the Huygens' principle for a bidimensional object. None of the approximations mentioned above have been used. This enables the computation of a diffraction pattern at any distance compatible with the scalar theory of diffraction. This vectorial algorithm has been implemented on workstations, on a Convex C-220 and on a Cray YMP computer. We focus our attention on the computing granularity of the problem and we present processing times and the associated performances for bidimensional images. Various holograms are computed and compared with those obtained by two traditional methods, namely, Fresnel transforms and the resolution of the rigorous scalar diffraction equation using discrete convolutions. We then consider the 3D case and modifications are proposed in order to parallelize this algorithm.

  20. Two glycosylase families diffusively scan DNA using a wedge residue to probe for and identify oxidatively damaged bases.

    PubMed

    Nelson, Shane R; Dunn, Andrew R; Kathe, Scott D; Warshaw, David M; Wallace, Susan S

    2014-05-20

    DNA glycosylases are enzymes that perform the initial steps of base excision repair, the principal repair mechanism that identifies and removes endogenous damages that occur in an organism's DNA. We characterized the motion of single molecules of three bacterial glycosylases that recognize oxidized bases, Fpg, Nei, and Nth, as they scan for damages on tightropes of λ DNA. We find that all three enzymes use a key "wedge residue" to scan for damage because mutation of this residue to an alanine results in faster diffusion. Moreover, all three enzymes bind longer and diffuse more slowly on DNA that contains the damages they recognize and remove. Using a sliding window approach to measure diffusion constants and a simple chemomechanical simulation, we demonstrate that these enzymes diffuse along DNA, pausing momentarily to interrogate random bases, and when a damaged base is recognized, they stop to evert and excise it.

  1. SINGLE CRYSTAL NEUTRON DIFFRACTION.

    SciTech Connect

    KOETZLE,T.F.

    2001-03-13

    Single-crystal neutron diffraction measures the elastic Bragg reflection intensities from crystals of a material, the structure of which is the subject of investigation. A single crystal is placed in a beam of neutrons produced at a nuclear reactor or at a proton accelerator-based spallation source. Single-crystal diffraction measurements are commonly made at thermal neutron beam energies, which correspond to neutron wavelengths in the neighborhood of 1 Angstrom. For high-resolution studies requiring shorter wavelengths (ca. 0.3-0.8 Angstroms), a pulsed spallation source or a high-temperature moderator (a ''hot source'') at a reactor may be used. When complex structures with large unit-cell repeats are under investigation, as is the case in structural biology, a cryogenic-temperature moderator (a ''cold source'') may be employed to obtain longer neutron wavelengths (ca. 4-10 Angstroms). A single-crystal neutron diffraction analysis will determine the crystal structure of the material, typically including its unit cell and space group, the positions of the atomic nuclei and their mean-square displacements, and relevant site occupancies. Because the neutron possesses a magnetic moment, the magnetic structure of the material can be determined as well, from the magnetic contribution to the Bragg intensities. This latter aspect falls beyond the scope of the present unit; for information on magnetic scattering of neutrons see Unit 14.3. Instruments for single-crystal diffraction (single-crystal diffractometers or SCDs) are generally available at the major neutron scattering center facilities. Beam time on many of these instruments is available through a proposal mechanism. A listing of neutron SCD instruments and their corresponding facility contacts is included in an appendix accompanying this unit.

  2. X-ray diffraction-based electronic structure calculations and experimental x-ray analysis for medical and materials applications

    NASA Astrophysics Data System (ADS)

    Mahato, Dip Narayan

    This thesis includes x-ray experiments for medical and materials applications and the use of x-ray diffraction data in a first-principles study of electronic structures and hyperfine properties of chemical and biological systems. Polycapillary focusing lenses were used to collect divergent x rays emitted from conventional x-ray tubes and redirect them to form an intense focused beam. These lenses are routinely used in microbeam x-ray fluorescence analysis. In this thesis, their potential application to powder diffraction and focused beam orthovoltage cancer therapy has been investigated. In conventional x-ray therapy, very high energy (˜ MeV) beams are used, partly to reduce the skin dose. For any divergent beam, the dose is necessarily highest at the entry point, and decays exponentially into the tissue. To reduce the skin dose, high energy beams, which have long absorption lengths, are employed, and rotated about the patient to enter from different angles. This necessitates large expensive specialized equipment. A focused beam could concentrate the dose within the patient. Since this is inherently skin dose sparing, lower energy photons could be employed. A primary concern in applying focused beams to therapy is whether the focus would be maintained despite Compton scattering within the tissue. To investigate this, transmission and focal spot sizes as a function of photon energy of two polycapillary focusing lenses were measured. The effects of tissue-equivalent phantoms of different thicknesses on the focal spot size were studied. Scatter fraction and depth dose were calculated. For powder diffraction, the polycapillary optics provide clean Gaussian peaks, which result in angular resolution that is much smaller than the peak width due to the beam convergence. Powder diffraction (also called coherent scatter) without optics can also be used to distinguish between tissue types that, because they have different nanoscale structures, scatter at different angles

  3. Residual motion of lung tumors in end-of-inhale respiratory gated radiotherapy based on external surrogates

    SciTech Connect

    Berbeco, Ross I.; Nishioka, Seiko; Shirato, Hiroki; Jiang, Steve B.

    2006-11-15

    It has been noted that some lung tumors exhibit large periodic motion due to respiration. To limit the amount of dose to healthy lung tissues, many clinics have begun gating radiotherapy treatment using externally placed surrogates. It has been observed by several institutions that the end-of-exhale (EOE) tumor position is more reproducible than other phases of the breathing cycle, so the gating window is often set there. From a treatment planning perspective, end-of-inhale (EOI) phase might be preferred for gating because the expanded lungs will further decrease the healthy tissue within the treatment field. We simulate gated treatment at the EOI phase, using a set of recently measured internal/external anatomy patient data. This paper attempts to answer three questions: (1) How much is the tumor residual motion when we use an external surrogate gating window at EOI? (2) How could we reduce the residual motion in the EOI gating window? (3) Is there a preference for amplitude- versus phase-based gating at EOI? We found that under free breathing conditions the residual motion of the tumors is much larger for EOI phase than for EOE phase. The mean values of residual motion at EOI were found to be 2.2 and 2.7 mm for amplitude- and phase-based gating, respectively, and, at EOE, 1.0 and 1.2 mm for amplitude- and phase-based gating, respectively. However, we note that the residual motion in the EOI gating window is correlated well with the reproducibility of the external surface position in the EOI phase. Using the results of a published breath-coaching study, we deduce that the residual motion of a lung tumor at EOI would approach that at EOE, with the same duty cycle (30%), under breath-coaching conditions. Additionally, we found that under these same conditions, phase-based gating approaches the same residual motion as amplitude-based gating, going from a 28% difference to 11%, for the patient with the largest difference between the two gating modalities. We conclude

  4. Multi-color quantum dot-based fluorescence immunoassay array for simultaneous visual detection of multiple antibiotic residues in milk.

    PubMed

    Song, Erqun; Yu, Mengqun; Wang, Yunyun; Hu, Weihua; Cheng, Dan; Swihart, Mark T; Song, Yang

    2015-10-15

    Antibiotic residues, which are among the most common contaminants in animal-based food products such as milk, have become a significant public health concern. Here, we combine a multicolor quantum dot (QD)-based immunofluorescence assay and an array analysis method to achieve simultaneous, sensitive and visual detection of streptomycin (SM), tetracycline (TC), and penicillin G (PC-G) in milk. Antibodies (Abs) for SM, TC and PC-G were conjugated to QDs with different emission wavelengths (QD 520 nm, QD 565 nm and QD 610 nm) to serve as detection probes (QD-Ab). Then a direct competitive fluorescent immunoassay was performed in antigen-coated microtiter plate wells for simultaneous qualitative and quantitative detection of SM, TC, and PC-G residues, based on fluorescence of the QD-Ab probes. The linear ranges for SM, TC and PC-G were 0.01-25 ng/mL, 0.01-25 ng/mL and 0.01-10 ng/mL, respectively, with detection limit of 5 pg/mL for each of them. Based on fluorescence of the QD-Ab probes, residues of the three antibiotics were determined visually and simultaneously. Compared with a commercial enzyme-linked immunosorbent assay kit, our method could achieve simultaneous analysis of multiple target antibiotics in multiple samples in a single run (high-throughput analysis) and improved accuracy and sensitivity for analysis of residues of the three antibiotics in authentic milk samples. This new analytical tool can play an important role in ameliorating the negative impact of the residual antibiotics on human health and the ecosystem. PMID:26002016

  5. 40 CFR Appendix Vii to Part 266 - Health-Based Limits for Exclusion of Waste-Derived Residues*

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Health-Based Limits for Exclusion of...-Based Limits for Exclusion of Waste-Derived Residues* Metals—TCLP Extract Concentration Limits...-chloroethyl) ether 111-44-4 3xE−04 Bis(chloromethyl) ether 542-88-1 2xE−06 Bis(2-ethylhexyl) phthalate...

  6. 40 CFR Appendix Vii to Part 266 - Health-Based Limits for Exclusion of Waste-Derived Residues*

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Health-Based Limits for Exclusion of...-Based Limits for Exclusion of Waste-Derived Residues* Metals—TCLP Extract Concentration Limits...-chloroethyl) ether 111-44-4 3xE−04 Bis(chloromethyl) ether 542-88-1 2xE−06 Bis(2-ethylhexyl) phthalate...

  7. 40 CFR Appendix Vii to Part 266 - Health-Based Limits for Exclusion of Waste-Derived Residues*

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 28 2012-07-01 2012-07-01 false Health-Based Limits for Exclusion of...-Based Limits for Exclusion of Waste-Derived Residues* Metals—TCLP Extract Concentration Limits...-chloroethyl) ether 111-44-4 3xE−04 Bis(chloromethyl) ether 542-88-1 2xE−06 Bis(2-ethylhexyl) phthalate...

  8. 40 CFR Appendix Vii to Part 266 - Health-Based Limits for Exclusion of Waste-Derived Residues*

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Health-Based Limits for Exclusion of...-Based Limits for Exclusion of Waste-Derived Residues* Metals—TCLP Extract Concentration Limits...-chloroethyl) ether 111-44-4 3xE−04 Bis(chloromethyl) ether 542-88-1 2xE−06 Bis(2-ethylhexyl) phthalate...

  9. 40 CFR Appendix Vii to Part 266 - Health-Based Limits for Exclusion of Waste-Derived Residues*

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Health-Based Limits for Exclusion of...-Based Limits for Exclusion of Waste-Derived Residues* Metals—TCLP Extract Concentration Limits...-chloroethyl) ether 111-44-4 3xE−04 Bis(chloromethyl) ether 542-88-1 2xE−06 Bis(2-ethylhexyl) phthalate...

  10. Undergraduate Experiment with Fractal Diffraction Gratings

    ERIC Educational Resources Information Center

    Monsoriu, Juan A.; Furlan, Walter D.; Pons, Amparo; Barreiro, Juan C.; Gimenez, Marcos H.

    2011-01-01

    We present a simple diffraction experiment with fractal gratings based on the triadic Cantor set. Diffraction by fractals is proposed as a motivating strategy for students of optics in the potential applications of optical processing. Fraunhofer diffraction patterns are obtained using standard equipment present in most undergraduate physics…

  11. [Optimization theory and practical application of membrane science technology based on resource of traditional Chinese medicine residue].

    PubMed

    Zhu, Hua-Xu; Duan, Jin-Ao; Guo, Li-Wei; Li, Bo; Lu, Jin; Tang, Yu-Ping; Pan, Lin-Mei

    2014-05-01

    Resource of traditional Chinese medicine residue is an inevitable choice to form new industries characterized of modem, environmental protection and intensive in the Chinese medicine industry. Based on the analysis of source and the main chemical composition of the herb residue, and for the advantages of membrane science and technology used in the pharmaceutical industry, especially membrane separation technology used in improvement technical reserves of traditional extraction and separation process in the pharmaceutical industry, it is proposed that membrane science and technology is one of the most important choices in technological design of traditional Chinese medicine resource industrialization. Traditional Chinese medicine residue is a very complex material system in composition and character, and scientific and effective "separation" process is the key areas of technology to re-use it. Integrated process can improve the productivity of the target product, enhance the purity of the product in the separation process, and solve many tasks which conventional separation is difficult to achieve. As integrated separation technology has the advantages of simplified process and reduced consumption, which are in line with the trend of the modern pharmaceutical industry, the membrane separation technology can provide a broad platform for integrated process, and membrane separation technology with its integrated technology have broad application prospects in achieving resource and industrialization process of traditional Chinese medicine residue. We discuss the principles, methods and applications practice of effective component resources in herb residue using membrane separation and integrated technology, describe the extraction, separation, concentration and purification application of membrane technology in traditional Chinese medicine residue, and systematically discourse suitability and feasibility of membrane technology in the process of traditional Chinese

  12. Biological butanol production from microalgae-based biodiesel residues by Clostridium acetobutylicum.

    PubMed

    Cheng, Hai-Hsuan; Whang, Liang-Ming; Chan, Kun-Chi; Chung, Man-Chien; Wu, Shu-Hsien; Liu, Cheng-Pin; Tien, Shih-Yuan; Chen, Shan-Yuan; Chang, Jo-Shu; Lee, Wen-Jhy

    2015-05-01

    This study conducted batch experiments to evaluate the potential of butanol production from microalgae biodiesel residues by Clostridium acetobutylicum. The results indicated that with 90 g/L of glucose as the sole substrate the highest butanol yield of 0.2 g/g-glucose was found, but the addition of butyrate significantly enhanced the butanol yield. The highest butanol yield of 0.4 g/g-glucose was found with 60 g/L of glucose and 18 g/L of butyrate. Using microalgae biodiesel residues as substrate, C. acetobutylicum produced 3.86 g/L of butanol and achieved butanol yield of 0.13 g/g-carbohydrate via ABE fermentation, but the results indicated that approximately one third of carbohydrate was not utilized by C. acetobutylicum. Biological butanol production from microalgae biodiesel residues can be possible, but further research on fermentation strategies are required to improve production yield.

  13. A method for the monitoring of metal recrystallization based on the in-situ measurement of the elastic energy release using neutron diffraction.

    PubMed

    Christien, F; Telling, M T F; Knight, K S; Le Gall, R

    2015-05-01

    A method is proposed for the monitoring of metal recrystallization using neutron diffraction that is based on the measurement of stored energy. Experiments were performed using deformed metal specimens heated in-situ while mounted at the sample position of the High Resolution Powder Diffractometer, HRPD (ISIS Facility), UK. Monitoring the breadth of the resulting Bragg lines during heating not only allows the time-dependence (or temperature-dependence) of the stored energy to be determined but also the recrystallized fraction. The analysis method presented here was developed using pure nickel (Ni270) specimens with different deformation levels from 0.29 to 0.94. In situ temperature ramping as well as isothermal annealing was undertaken. The method developed in this work allows accurate and quantitative monitoring of the recrystallization process. The results from neutron diffraction are satisfactorily compared to data obtained from calorimetry and hardness measurements.

  14. Direct patterning of a SiO2-based diffractive optical element on a lateral-type LED by using nano-imprint technology

    NASA Astrophysics Data System (ADS)

    Yoo, Seunghwan; Chae, Suyong; Jeong, Hakgeun; Jang, Cheol-Yong; Park, Hyeong-Ho

    2013-11-01

    We report the direct patterning of diffractive optical elements (DOEs) on a flat conventional lateral-type light-emitting diode (LED) surface. Silicon dioxide, used as a diffractive optical element, was deposited on the flat surface of an LED by using plasma-enhanced chemical vapor deposition and was patterned by using nano-imprint lithography and ion-coupled plasma etching to produce nanometer-scale DOEs. This method suggests a new approach for the mass production of DOEs by minimizing the size of the optical device through direct patterning on the LED surface. The resulting DOEs also act as focal Fresnel lenses, leading to an enhancement of the external light-extraction efficiency of lateral-type LEDs based on the scattering effect and the concentration of the emitted light.

  15. NEUTRON-DIFFRACTION STUDY ON PLASTIC BEHAVIOR OF A NICKEL-BASED ALLOY UNDER THE MONOTONIC-TENSION AND THE LOW-CYCLE-FATIGUE EXPERIMENTS

    SciTech Connect

    Huang, E-Wen; Barabash, Rozaliya; Clausen, Bjorn; Wang, Yandong; Yang, Dr Ren; Li, Li; Choo, Hahn; Liaw, Peter K

    2007-01-01

    The plastic behavior of an annealed HASTELLOY C-22HS alloy, a face-centered cubic (FCC), nickel-based superalloy, was examined by in-situ neutron-diffraction measurements at room temperature. Both monotonic-tension and low-cycle-fatigue experiments were conducted. Monotonic-tension straining and cyclic-loading deformation were studied as a function of stress. The plastic behavior during deformation is discussed in light of the relationship between the stress and dislocation-density evolution. The calculated dislocation-density evolution within the alloy reflects the strain hardening and cyclic hardening/softening. Experimentally determined lattice strains are compared to verify the hardening mechanism at selected stress levels for tension and cyclic loadings. Combined with calculations of the dislocation densities, the neutron-diffraction experiments provide direct information about the strain and cyclic hardening of the alloy.

  16. Neutron Diffraction Study on Plastic behavior of a Nickel-Based Alloy Under the Monotonic-Tension and the Low-Cyclic-Fatigue Experiments

    SciTech Connect

    Huang, E.-W.; Barabash, R.; Clausen, B.; Wang, Y.; Yang, R.; Li, L.; Choo, H.; Liaw, P.K.

    2007-11-02

    The plastic behavior of an annealed HASTELLOY C-22HS alloy, a face-centered cubic (FCC), nickel-based superalloy, was examined by in-situ neutron-diffraction measurements at room temperature. Both monotonic-tension and low-cycle-fatigue experiments were conducted. Monotonic-tension straining and cyclic-loading deformation were studied as a function of stress. The plastic behavior during deformation is discussed in light of the relationship between the stress and dislocation-density evolution. The calculated dislocation-density evolution within the alloy reflects the strain hardening and cyclic hardening/softening. Experimentally determined lattice strains are compared to verify the hardening mechanism at selected stress levels for tension and cyclic loadings. Combined with calculations of the dislocation densities, the neutron-diffraction experiments provide direct information about the strain and cyclic hardening of the alloy.

  17. A method for the monitoring of metal recrystallization based on the in-situ measurement of the elastic energy release using neutron diffraction

    SciTech Connect

    Christien, F. Le Gall, R.; Telling, M. T. F.; Knight, K. S.

    2015-05-15

    A method is proposed for the monitoring of metal recrystallization using neutron diffraction that is based on the measurement of stored energy. Experiments were performed using deformed metal specimens heated in-situ while mounted at the sample position of the High Resolution Powder Diffractometer, HRPD (ISIS Facility), UK. Monitoring the breadth of the resulting Bragg lines during heating not only allows the time-dependence (or temperature-dependence) of the stored energy to be determined but also the recrystallized fraction. The analysis method presented here was developed using pure nickel (Ni270) specimens with different deformation levels from 0.29 to 0.94. In situ temperature ramping as well as isothermal annealing was undertaken. The method developed in this work allows accurate and quantitative monitoring of the recrystallization process. The results from neutron diffraction are satisfactorily compared to data obtained from calorimetry and hardness measurements.

  18. A method for the monitoring of metal recrystallization based on the in-situ measurement of the elastic energy release using neutron diffraction

    NASA Astrophysics Data System (ADS)

    Christien, F.; Telling, M. T. F.; Knight, K. S.; Le Gall, R.

    2015-05-01

    A method is proposed for the monitoring of metal recrystallization using neutron diffraction that is based on the measurement of stored energy. Experiments were performed using deformed metal specimens heated in-situ while mounted at the sample position of the High Resolution Powder Diffractometer, HRPD (ISIS Facility), UK. Monitoring the breadth of the resulting Bragg lines during heating not only allows the time-dependence (or temperature-dependence) of the stored energy to be determined but also the recrystallized fraction. The analysis method presented here was developed using pure nickel (Ni270) specimens with different deformation levels from 0.29 to 0.94. In situ temperature ramping as well as isothermal annealing was undertaken. The method developed in this work allows accurate and quantitative monitoring of the recrystallization process. The results from neutron diffraction are satisfactorily compared to data obtained from calorimetry and hardness measurements.

  19. Understanding the deformation mechanism of individual phases of a ZrTi-based bulk metallic glass matrix composite using in situ diffraction and imaging methods

    SciTech Connect

    Huang, Yongjiang E-mail: yjhuang@hit.edu.cn; Khong, J. C.; Mi, J. E-mail: yjhuang@hit.edu.cn; Connolley, Thomas

    2014-01-20

    The plasticity of a ZrTi-based bulk metallic glass composite consisting of glassy matrix and crystalline dendritic phase was studied in-situ under identical tensile loading conditions using scanning electron microscopy and synchrotron X-ray diffraction. A generic procedure was developed to separate the diffraction information of the crystalline phases away from that of the matrix and to precisely calculate the microscopic strains of the two phases at different macroscopic load steps. In this way, the time-evolved quantitative links between shear bands nucleation/propagation and the corresponding microscopic stress fields around them are established, providing more quantitative understanding on (1) how the shear bands are driven by the local stress field, and (2) the critical stresses required for the shear bands to nucleate in the crystalline phase, propagate through the crystalline/matrix interface, and finally into the matrix.

  20. Neutron-Diffraction Evidence for the Ferrimagnetic Ground State of a Molecule-Based Magnet with Weakly Coupled Sublattices

    SciTech Connect

    Fishman, Randy Scott; Campo, Javier; Vos, Thomas E.; Miller, Joel S.

    2012-01-01

    The diruthenium compound [Ru2(O2CMe)4]3[Cr(CN)6] contains two weakly coupled, ferrimag- netically ordered sublattices occupying the same volume. The magnetic field Hc 800 Oe required to align the two sublattice moments is proportional to the antiferromagnetic dipolar interaction Kc B Hc 5 10 3 meV between sublattices. Powder neutron-diffraction measurements on a deuterated sample reveal that the sublattice moments are restricted by the anisotropy of the diruthenium paddle-wheel complexes to the cubic diagonals. Those measurements also suggest that the quantum corrections to the ground state are significant.

  1. Electromagnetic diffraction efficiencies for plane reflection diffraction gratings

    NASA Technical Reports Server (NTRS)

    Marathay, A. S.; Shrode, T. E.

    1973-01-01

    Results are presented of research activities on holographic grating research. A large portion of this work was performed using rigorous vector diffraction theory, therefore, the necessary theory has been included in this report. The diffraction efficiency studies were continued using programs based on a rigorous theory. The simultaneous occurrence of high diffraction efficiencies and the phenomenon of double Wood's anomalies is demonstrated along with a graphic method for determining the necessary grating parameters. Also, an analytical solution for a grating profile that is perfectly blazed is obtained. The performance of the perfectly blazed grating profile is shown to be significantly better than grating profiles previously studied. Finally, a proposed method is described for the analysis of coarse echelle gratings using rigorous vector diffraction that is currently being developed.

  2. Nitrogen availability from residues-based biochar at two pyrolisis temperatures

    NASA Astrophysics Data System (ADS)

    Coscione, Aline Renee; Silveira Bibar, Maria Paula; de Andrade, Cristiano Alberto

    2014-05-01

    , only SS4 and CM4 presented a positive nitrogen balance, reaching 8 and 9 % of the nitrogen added by biochar samples release to the soil, respectively. A first order kinetic model was adjusted for SS4 nitrogen release, enabling the calculation of half life (10 days), potential available nitrogen (76.5 mg/kg) and the speed of the process. However, compared to SS4 the standard nitrogen availability of sewage sludge is up to 30% of its Kjeldahl nitrogen. For organic residues with C/N ratios lower than 20 applied to the soil a fast degradation, with the corresponding increase in inorganic nitrogen availability is expect. Although all the biochar samples tested had C/N ratios below that cutting point, just 2 of 8 presented inorganic nitrogen available in the soil+biochar mixtures. These results show that soil incubation tests are ultimate for the evaluation of the nitrogen potential release to the soil. Low temperature SS based biochar may offer additional nitrogen release to soil besides other soil conditioning properties.

  3. Description and evaluation of nuclear masses based on residual proton-neutron interactions

    SciTech Connect

    Fu, G. J.; Lei, Y.; Jiang, H.; Zhao, Y. M.; Sun, B.; Arima, A.

    2011-09-15

    In this paper we study the residual proton-neutron interactions and make use of the systematics of these interactions to describe experimental data of nuclear masses and to predict some of the unknown masses. The odd-even effect staggering of the residual proton-neutron interaction between the last proton and the last neutron is found and argued in terms of pairing interactions. Two local mass relations, which work very accurately for masses of four neighboring nuclei, are discovered. The accuracy of our predicted masses for medium and heavy nuclei is competitive with that of the AME2003 extrapolations, with the virtue of simplicity.

  4. Determination of white phosphorus residues in ducks: An atomic emission detection/compound-independent calibration-based method of generating residue data for risk assessment and environmental monitoring

    SciTech Connect

    Johnston, J.J.; Goldade, D.A.; Kohler, D.J.; Cummings, J.L.

    2000-05-01

    Analysis of phosphorus concentrations in the gizzards of ducks harvested from munitions sites is necessary to ascertain if acute phosphorus toxicity was the cause of death and to estimate potential secondary hazards to predators and scavengers, such as eagles that readily consume the dead ducks. Gas chromatography-atomic emission detection analysis permitted compound-independent quantification of white phosphorus standards following analysis of the stable phosphorus-containing compound triethyl phosphate. The white phosphorus standards were then used to quantify white phosphorus residues in duck gizzard extracts by gas chromatography-flame photometric detection analysis. For gizzards containing less than 0.01 {micro}g of phosphorus, quantification was based on a three-point calibration curve. For gizzards containing 0.01 {micro}g or more of white phosphorus, single-point calibration was used. Mean recoveries for phosphorus-fortified gizzards ranged from 73 to 91%. The method limit of detection was 0.013 {micro}g of phosphorus. This method was successfully applied to the quantification of white phosphorus in ducks collected from Eagle River Flats, AK. Potential applications to risk assessment and environmental monitoring are also discussed.

  5. X-ray diffraction study of spontaneous strain in the iron-based superconductor Sr4V2Fe2As2O6-δ

    NASA Astrophysics Data System (ADS)

    Saito, Masahiro; Fujishita, Hideshi; Okamoto, Hiroyuki; Kobayashi, Yoshiaki; Sato, Masatoshi

    2015-12-01

    The lattice parameters of the iron-based superconductor Sr4V2Fe2As2O6-δwere measured by the X-ray diffraction method between 10 K and 270 K. Anomalous changes in the lattice parameter c could be clearly detected at the magnetic phase transition and the superconducting transition. Based on the Landau theory of phase transition, these anomalies can be attributed to a spontaneous strain caused by the coupling between the strain and an order parameter. The signs of the uniaxial pressure derivative along the c axis of the transition temperatures are estimated using the Ehrenfest relation.

  6. A Sensitive Gel-based Method Combining Distinct Cyclophellitol-based Probes for the Identification of Acid/Base Residues in Human Retaining β-Glucosidases*

    PubMed Central

    Kallemeijn, Wouter W.; Witte, Martin D.; Voorn-Brouwer, Tineke M.; Walvoort, Marthe T. C.; Li, Kah-Yee; Codée, Jeroen D. C.; van der Marel, Gijsbert A.; Boot, Rolf G.; Overkleeft, Herman S.; Aerts, Johannes M. F. G.

    2014-01-01

    Retaining β-exoglucosidases operate by a mechanism in which the key amino acids driving the glycosidic bond hydrolysis act as catalytic acid/base and nucleophile. Recently we designed two distinct classes of fluorescent cyclophellitol-type activity-based probes (ABPs) that exploit this mechanism to covalently modify the nucleophile of retaining β-glucosidases. Whereas β-epoxide ABPs require a protonated acid/base for irreversible inhibition of retaining β-glucosidases, β-aziridine ABPs do not. Here we describe a novel sensitive method to identify both catalytic residues of retaining β-glucosidases by the combined use of cyclophellitol β-epoxide- and β-aziridine ABPs. In this approach putative catalytic residues are first substituted to noncarboxylic amino acids such as glycine or glutamine through site-directed mutagenesis. Next, the acid/base and nucleophile can be identified via classical sodium azide-mediated rescue of mutants thereof. Selective labeling with fluorescent β-aziridine but not β-epoxide ABPs identifies the acid/base residue in mutagenized enzyme, as only the β-aziridine ABP can bind in its absence. The Absence of the nucleophile abolishes any ABP labeling. We validated the method by using the retaining β-glucosidase GBA (CAZy glycosylhydrolase family GH30) and then applied it to non-homologous (putative) retaining β-glucosidases categorized in GH1 and GH116: GBA2, GBA3, and LPH. The described method is highly sensitive, requiring only femtomoles (nanograms) of ABP-labeled enzymes. PMID:25344605

  7. Discriminating the native structure from decoys using scoring functions based on the residue packing in globular proteins

    PubMed Central

    2009-01-01

    Background Setting the rules for the identification of a stable conformation of a protein is of utmost importance for the efficient generation of structures in computer simulation. For structure prediction, a considerable number of possible models are generated from which the best model has to be selected. Results Two scoring functions, Rs and Rp, based on the consideration of packing of residues, which indicate if the conformation of an amino acid sequence is native-like, are presented. These are defined using the solvent accessible surface area (ASA) and the partner number (PN) (other residues that are within 4.5 Å) of a particular residue. The two functions evaluate the deviation from the average packing properties (ASA or PN) of all residues in a polypeptide chain corresponding to a model of its three-dimensional structure. While simple in concept and computationally less intensive, both the functions are at least as efficient as any other energy functions in discriminating the native structure from decoys in a large number of standard decoy sets, as well as on models submitted for the targets of CASP7. Rs appears to be slightly more effective than Rp, as determined by the number of times the native structure possesses the minimum value for the function and its separation from the average value for the decoys. Conclusion Two parameters, Rs and Rp, are discussed that can very efficiently recognize the native fold for a sequence from an ensemble of decoy structures. Unlike many other algorithms that rely on the use of composite scoring function, these are based on a single parameter, viz., the accessible surface area (or the number of residues in contact), but still able to capture the essential attribute of the native fold. PMID:20038291

  8. Residual Diagrams Based on a Remarkably Simple Result Concerning the Variances of Maximum Likelihood Estimators.

    ERIC Educational Resources Information Center

    Andersen, Erling B.

    2002-01-01

    Presents a simple result concerning variances of maximum likelihood (ML) estimators. The result allows for construction of residual diagrams to evaluate whether ML estimators derived from independent samples can be assumed to be equal apart from random errors. Applies this result to the polytomous Rasch model. (SLD)

  9. Elucidating the exact role of engineered CRABPII residues for the formation of a retinal protonated Schiff base

    SciTech Connect

    Vasileiou, Chrysoula; Wang, Wenjing; Jia, Xiaofei; Lee, Kin Sing Stephen; Watson, Camille T.; Geiger, James H.; Borhan, Babak

    2010-03-04

    Cellular Retinoic Acid Binding Protein II (CRABPII) has been reengineered to specifically bind and react with all-trans-retinal to form a protonated Schiff base. Each step of this process has been dissected and four residues (Lys132, Tyr134, Arg111, and Glu121) within the CRABPII binding site have been identified as crucial for imine formation and/or protonation. The precise role of each residue has been examined through site directed mutagenesis and crystallographic studies. The crystal structure of the R132K:L121E-CRABPII (PDB-3I17) double mutant suggests a direct interaction between engineered Glu121 and the native Arg111, which is critical for both Schiff base formation and protonation.

  10. X-Ray Diffraction.

    ERIC Educational Resources Information Center

    Smith, D. K.; Smith, K. L.

    1980-01-01

    Reviews applications in research and analytical characterization of compounds and materials in the field of X-ray diffraction, emphasizing new developments in applications and instrumentation in both single crystal and powder diffraction. Cites 414 references. (CS)

  11. Aluminum-based water treatment residual use in a constructed wetland for capturing urban runoff phosphorus: Column study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aluminum-based water treatment residuals (Al-WTR) have a strong affinity to sorb phosphorus. In a proof-of-concept greenhouse column study, Al-WTR was surface-applied at 0, 62, 124, and 248 Mg/ha to 15 cm of soil on top of 46 cm of sand; Al-WTR rates were estimated to capture 0, 10, 20, and 40 year...

  12. Aging of aluminum/iron-based drinking water treatment residuals in lake water and their association with phosphorus immobilization capability.

    PubMed

    Wang, Changhui; Yuan, Nannan; Pei, Yuansheng; Jiang, He-Long

    2015-08-15

    Aluminum and Fe-based drinking water treatment residuals (DWTRs) have shown a high potential for use by geoengineers in internal P loading control in lakes. In this study, aging of Al/Fe-based DWTRs in lake water under different pH and redox conditions associated with their P immobilization capability was investigated based on a 180-day incubation test. The results showed that the DWTRs before and after incubation under different conditions have similar structures, but their specific surface area and pore volume, especially mesopores with radius at 2.1-5.0 nm drastically decreased. The oxalate extractable Al contents changed little although a small amount of Al transformed from oxidizable to residual forms. The oxalate extractable Fe contents also decreased by a small amount, but the transformation from oxidizable to residual forms were remarkable, approximately by 14.6%. However, the DWTRs before and after incubation had similar P immobilization capabilities in solutions and lake sediments. Even the maximum P adsorption capacity estimated by the Langmuir model increased after incubation. Therefore, it was not necessary to give special attention to the impact of Al and Fe aging on the effectiveness of DWTRs for geoengineering in lakes.

  13. Physicochemical bases of differences between the sedimentometric and laser-diffraction techniques of soil particle-size analysis

    NASA Astrophysics Data System (ADS)

    Fedotov, G. N.; Shein, E. V.; Putlyaev, V. I.; Arkhangel'Skaya, T. A.; Eliseev, A. V.; Milanovskii, E. Yu.

    2007-03-01

    Comparison of the particle-size distributions in different soils showed that the sedimentation method (Kachinskii pipette method) gives higher (by 1.5-5 times) values of the clay content than the laser diffraction method. This is related to the significant variation in density of soil solids, which is taken to be constant in the sedimentation method. Therefore, particles of significantly larger size and lower density fall into this fraction. Using optical, electron, and confocal microscopy, it was shown that the low density of soil particles of silt size falling into the sedimentometric clay fraction is related to the organomineral shell (film) around the soil microparticles. This shell contributes to the linking of microparticles into aggregates at the lower average density. As a result, these aggregates have significantly larger size and lower density and settle with the same velocity as the small particles with the average density of the solid phase during the sedimentation particle-size analysis.

  14. Synthesis and single crystal x-ray diffraction study of a Schiff base derived from 4-acylpyrazolone and 2-aminophenol

    SciTech Connect

    Sharma, Naresh; Kant, Rajni Gupta, Vivek K.; Jadeja, R. N.

    2014-04-24

    The title compound, (Z)-1-(3-chlorophenyl)-4[1((2hydroxyphenyl)amino)propylidene] -3-methyl-1H-pyrazol-5(4H)-one was synthesized by refluxing compound 1-(m-chlorophenyl)-3-methyl-4-propionyl-5-pyrazolone, with 2-aminophenol in ethanol. The compound crystallizes in the orthorhombic crystal system with space group Pca2{sub 1} having unit cell parameters: a = 26.2993(8), b = 7.0724(2) and c = 18.7170(5)Å. The structure contains two crystallographically independent molecules, A, and, B, in the asymmetric unit cell. The crystal structure was solved by direct method using single crystal X-ray diffraction data collected at room temperature and refined by full-matrix least-squares procedures to a final R- value of 0.049 for 5207 observed reflections.

  15. Sensing of human plasma fibrinogen on polished, chemically etched and carbon treated titanium surfaces by diffractive optical element based sensor.

    PubMed

    Silvennoinen, Raimo; Vetterl, Vladimir; Hason, Stanislav; Tuononen, Heikki; Silvennoinen, Martti; Myller, Kari; Cvrcek, Ladislav; Vanek, Jiri; Prachar, Patrik

    2008-07-01

    Adsorption of human plasma fibrinogen (HPF) on 6 differently treated titanium samples (polished, polished and etched, and 4 titanium carbide coatings samples produced by using plasma-enhanced chemical vapour deposition (PECVD) method) is investigated by using diffractive optical element (DOE) sensor. Permittivity (susceptibility) change and fluctuation in optical roughness (R(opt)) of treated titanium surface in the presence of background electrolyte without and with HPF molecules are sensed by using DOE sensor and optical ellipsometry. Correlation between transmitted light and thickness of molecule layer was found. The findings allow to sense temporal organization and severity of adsorption of nano-scale HPF molecules on polished, on polished and etched, and on titanium carbide surface.

  16. Dimorphism of RF3 ( R = La-Nd) crystals based on the data of X-ray diffraction studies

    NASA Astrophysics Data System (ADS)

    Bolotina, N. B.; Chernaya, T. S.; Verin, I. A.; Khrykina, O. N.; Sobolev, B. P.

    2016-01-01

    The ratio of two forms of tysonite in nominally pure single crystals of RF3 ( R = La-Nd) obtained from melts under identical conditions (the as-grown state) is studied for the first time by X-ray diffraction. Crystals of RF3 with R = La-Nd belong to the β-LaF3 structural type (space group Pbar 3c1, Z = 6) and form twins. Samples 0.2-0.4 in diameter contain inclusions of the high-temperature a form (space group P63/ mmc, Z = 2). It is shown that twinning and dimorphism of the RF3 crystals ( R = La-Nd) have a common structural basis.

  17. Electromagnetic diffraction by plane reflection diffraction gratings

    NASA Technical Reports Server (NTRS)

    Bocker, R. P.; Marathay, A. S.

    1972-01-01

    A plane wave theory was developed to study electromagnetic diffraction by plane reflection diffraction gratings of infinite extent. A computer program was written to calculate the energy distribution in the various orders of diffraction for the cases when the electric or magnetic field vectors are parallel to the grating grooves. Within the region of validity of this theory, results were in excellent agreement with those in the literature. Energy conservation checks were also made to determine the region of validity of the plane wave theory. The computer program was flexible enough to analyze any grating profile that could be described by a single value function f(x). Within the region of validity the program could be used with confidence. The computer program was used to investigate the polarization and blaze properties of the diffraction grating.

  18. Sand sources and transport pathways for the San Francisco Bay coastal system, based on X-ray diffraction mineralogy

    USGS Publications Warehouse

    Hein, James R.; Mizell, Kira; Barnard, Patrick L.; Barnard, P.L.; Jaffee, B.E.; Schoellhamer, D.H.

    2013-01-01

    The mineralogical compositions of 119 samples collected from throughout the San Francisco Bay coastal system, including bayfloor and seafloor, area beaches, cliff outcrops, and major drainages, were determined using X-ray diffraction (XRD). Comparison of the mineral concentrations and application of statistical cluster analysis of XRD spectra allowed for the determination of provenances and transport pathways. The use of XRD mineral identifications provides semi-quantitative compositions needed for comparisons of beach and offshore sands with potential cliff and river sources, but the innovative cluster analysis of XRD diffraction spectra provides a unique visualization of how groups of samples within the San Francisco Bay coastal system are related so that sand-sized sediment transport pathways can be inferred. The main vector for sediment transport as defined by the XRD analysis is from San Francisco Bay to the outer coast, where the sand then accumulates on the ebb tidal delta and also moves alongshore. This mineralogical link defines a critical pathway because large volumes of sediment have been removed from the Bay over the last century via channel dredging, aggregate mining, and borrow pit mining, with comparable volumes of erosion from the ebb tidal delta over the same period, in addition to high rates of shoreline retreat along the adjacent, open-coast beaches. Therefore, while previously only a temporal relationship was established, the transport pathway defined by mineralogical and geochemical tracers support the link between anthropogenic activities in the Bay and widespread erosion outside the Bay. The XRD results also establish the regional and local importance of sediment derived from cliff erosion, as well as both proximal and distal fluvial sources. This research is an important contribution to a broader provenance study aimed at identifying the driving forces for widespread geomorphic change in a heavily urbanized coastal-estuarine system.

  19. Unexpected stimulation of soil methane uptake as emergent property of agricultural soils following bio-based residue application.

    PubMed

    Ho, Adrian; Reim, Andreas; Kim, Sang Yoon; Meima-Franke, Marion; Termorshuizen, Aad; de Boer, Wietse; van der Putten, Wim H; Bodelier, Paul L E

    2015-10-01

    Intensification of agriculture to meet the global food, feed, and bioenergy demand entail increasing re-investment of carbon compounds (residues) into agro-systems to prevent decline of soil quality and fertility. However, agricultural intensification decreases soil methane uptake, reducing, and even causing the loss of the methane sink function. In contrast to wetland agricultural soils (rice paddies), the methanotrophic potential in well-aerated agricultural soils have received little attention, presumably due to the anticipated low or negligible methane uptake capacity in these soils. Consequently, a detailed study verifying or refuting this assumption is still lacking. Exemplifying a typical agricultural practice, we determined the impact of bio-based residue application on soil methane flux, and determined the methanotrophic potential, including a qualitative (diagnostic microarray) and quantitative (group-specific qPCR assays) analysis of the methanotrophic community after residue amendments over 2 months. Unexpectedly, after amendments with specific residues, we detected a significant transient stimulation of methane uptake confirmed by both the methane flux measurements and methane oxidation assay. This stimulation was apparently a result of induced cell-specific activity, rather than growth of the methanotroph population. Although transient, the heightened methane uptake offsets up to 16% of total gaseous CO2 emitted during the incubation. The methanotrophic community, predominantly comprised of Methylosinus may facilitate methane oxidation in the agricultural soils. While agricultural soils are generally regarded as a net methane source or a relatively weak methane sink, our results show that methane oxidation rate can be stimulated, leading to higher soil methane uptake. Hence, even if agriculture exerts an adverse impact on soil methane uptake, implementing carefully designed management strategies (e.g. repeated application of specific residues) may

  20. Unexpected stimulation of soil methane uptake as emergent property of agricultural soils following bio-based residue application.

    PubMed

    Ho, Adrian; Reim, Andreas; Kim, Sang Yoon; Meima-Franke, Marion; Termorshuizen, Aad; de Boer, Wietse; van der Putten, Wim H; Bodelier, Paul L E

    2015-10-01

    Intensification of agriculture to meet the global food, feed, and bioenergy demand entail increasing re-investment of carbon compounds (residues) into agro-systems to prevent decline of soil quality and fertility. However, agricultural intensification decreases soil methane uptake, reducing, and even causing the loss of the methane sink function. In contrast to wetland agricultural soils (rice paddies), the methanotrophic potential in well-aerated agricultural soils have received little attention, presumably due to the anticipated low or negligible methane uptake capacity in these soils. Consequently, a detailed study verifying or refuting this assumption is still lacking. Exemplifying a typical agricultural practice, we determined the impact of bio-based residue application on soil methane flux, and determined the methanotrophic potential, including a qualitative (diagnostic microarray) and quantitative (group-specific qPCR assays) analysis of the methanotrophic community after residue amendments over 2 months. Unexpectedly, after amendments with specific residues, we detected a significant transient stimulation of methane uptake confirmed by both the methane flux measurements and methane oxidation assay. This stimulation was apparently a result of induced cell-specific activity, rather than growth of the methanotroph population. Although transient, the heightened methane uptake offsets up to 16% of total gaseous CO2 emitted during the incubation. The methanotrophic community, predominantly comprised of Methylosinus may facilitate methane oxidation in the agricultural soils. While agricultural soils are generally regarded as a net methane source or a relatively weak methane sink, our results show that methane oxidation rate can be stimulated, leading to higher soil methane uptake. Hence, even if agriculture exerts an adverse impact on soil methane uptake, implementing carefully designed management strategies (e.g. repeated application of specific residues) may

  1. Remote sensing-based estimates of annual and seasonal emissions from crop residue burning in the contiguous United States.

    PubMed

    McCarty, Jessica L

    2011-01-01

    Crop residue burning is an extensive agricultural practice in the contiguous United States (CONUS). This analysis presents the results of a remote sensing-based study of crop residue burning emissions in the CONUS for the time period 2003-2007 for the atmospheric species of carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), nitrogen dioxide (NO2, sulfur dioxide (SO2), PM2.5 (particulate matter [PM] < or = 2.5 microm in aerodynamic diameter), and PM10 (PM < or = 10 microm in aerodynamic diameter). Cropland burned area and associated crop types were derived from Moderate Resolution Imaging Spectroradiometer (MODIS) products. Emission factors, fuel load, and combustion completeness estimates were derived from the scientific literature, governmental reports, and expert knowledge. Emissions were calculated using the bottom-up approach in which emissions are the product of burned area, fuel load, and combustion completeness for each specific crop type. On average, annual crop residue burning in the CONUS emitted 6.1 Tg of CO2, 8.9 Gg of CH4, 232.4 Gg of CO, 10.6 Gg of NO2, 4.4 Gg of SO2, 20.9 Gg of PM2.5, and 28.5 Gg of PM10. These emissions remained fairly consistent, with an average interannual variability of crop residue burning emissions of +/- 10%. The states with the highest emissions were Arkansas, California, Florida, Idaho, Texas, and Washington. Most emissions were clustered in the southeastern United States, the Great Plains, and the Pacific Northwest. Air quality and carbon emissions were concentrated in the spring, summer, and fall, with an exception because of winter harvesting of sugarcane in Florida, Louisiana, and Texas. Sugarcane, wheat, and rice residues accounted for approximately 70% of all crop residue burning and associated emissions. Estimates of CO and CH4 from agricultural waste burning by the U.S. Environmental Protection Agency were 73 and 78% higher than the CO and CH4 emission estimates from this analysis, respectively. This analysis

  2. High-power ({gt}0.9 W cw) diffraction-limited semiconductor laser based on a fiber Bragg grating external cavity

    SciTech Connect

    Cornwell, D.M. , Jr.; Thomas, H.J.

    1997-02-01

    We have developed a high-power ({gt}0.9 W cw) diffraction-limited semiconductor laser based on a tapered semiconductor optical amplifier using a fiber Bragg grating in an external cavity configuration. Frequency-selective feedback from the fiber grating is injected into the amplifier via direct butt coupling through a single mode fiber, resulting in a spectrally stable and narrow ({lt}0.3 nm) high-power laser for solid-state laser pumping, laser remote sensing, and optical communications. {copyright} {ital 1997 American Institute of Physics.}

  3. High power, diffraction limited picosecond oscillator based on Nd:GdVO4 bulk crystal with σ polarized in-band pumping.

    PubMed

    Lin, Hua; Guo, Jie; Gao, Peng; Yu, Hai; Liang, Xiaoyan

    2016-06-27

    We report on a high power passively mode-locked picosecond oscillator based on Nd:GdVO4 crystal with σ polarized in-band pumping. Thermal gradient and thermal aberration was greatly decreased with proposed configuration. Maximum output power of 37 W at 81 MHz repetition rate with 19.3 ps pulse duration was achieved directly from Nd:GdVO4 oscillator, corresponding to 51% optical efficiency. The oscillator maintained diffraction limited beam quality of M2 < 1.05 at different output coupling with pulse duration between 11.2 ps to 19.3 ps.

  4. Performance of an optical encoder based on a nondiffractive beam implemented with a specific photodetection integrated circuit and a diffractive optical element.

    PubMed

    Quintián, Fernando Perez; Calarco, Nicolás; Lutenberg, Ariel; Lipovetzky, José

    2015-09-01

    In this paper, we study the incremental signal produced by an optical encoder based on a nondiffractive beam (NDB). The NDB is generated by means of a diffractive optical element (DOE). The detection system is composed by an application specific integrated circuit (ASIC) sensor. The sensor consists of an array of eight concentric annular photodiodes, each one provided with a programmable gain amplifier. In this way, the system is able to synthesize a nonuniform detectivity. The contrast, amplitude, and harmonic content of the sinusoidal output signal are analyzed. The influence of the cross talk among the annular photodiodes is placed in evidence through the dependence of the signal contrast on the wavelength.

  5. On the Feasibility of Eddy Current Characterization of the Near-Surface Residual Stress Distribution in Nickel-Base Superalloys

    SciTech Connect

    Blodgett, Mark P.; Nagy, Peter B.

    2004-02-26

    In light of its frequency-dependent penetration depth, the measurement of eddy current conductivity has been suggested as a possible means to allow the nondestructive evaluation of subsurface residual stresses in shot-peened specimens. This technique is based on the so-called electroelastic effect, i.e., the stress-dependence of the electrical conductivity. Unfortunately, the relatively small ({approx}1%) change in electrical conductivity caused by the presence of compressive residual stresses is often distorted, or even completely overshadowed, by the accompanying conductivity loss caused by cold work and surface roughness effects. Recently, it was observed that, in contrast with most other materials, shot-peened Waspaloy and IN100 specimens exhibit an apparent increase in electrical conductivity at increasing inspection frequencies. This observation by itself indicates that in these materials the measured conductivity change is probably dominated by residual stress effects, since both surface roughness and increased dislocation density are known to decrease rather than increase the conductivity and the presence of crystallographic texture does not affect the electrical conductivity of these materials, which crystallize in cubic symmetry. Our preliminary experiments indicate that probably there exists a unique 'window of opportunity' for eddy current NDE in nickel-base superalloys. We identified five major effects that contribute to this fortunate constellation of material properties, which will be reviewed in this presentation.

  6. A PFM based digital pixel with off-pixel residue measurement for 15μm pitch MWIR FPAs

    NASA Astrophysics Data System (ADS)

    Abbasi, Shahbaz; Shafique, Atia; Galioglu, Arman; Ceylan, Omer; Yazici, Melik; Gurbuz, Yasar

    2016-05-01

    Digital pixels based on pulse frequency modulation (PFM) employ counting techniques to achieve very high charge handling capability compared to their analog counterparts. Moreover, extended counting methods making use of leftover charge (residue) on the integration capacitor help improve the noise performance of these pixels. However, medium wave infrared (MWIR) focal plane arrays (FPAs) having smaller pixel pitch are constrained in terms of pixel area which makes it difficult to add extended counting circuitry to the pixel. Thus, this paper investigates the performance of digital pixels employing off-pixel residue measurement. A circuit prototype of such a pixel has been designed for 15μm pixel pitch and fabricated in 90nm CMOS. The prototype is composed of a pixel front-end based on a PFM loop. The frontend is a modified version of conventional design providing a means for buffering the signal that needs to be converted to a digital value by an off-pixel ADC. The pixel has an integration phase and a residue measurement phase. Measured integration performance of the pixel has been reported in this paper for various detector currents and integration times.

  7. Quantitation of residual trypsin in cell-based therapeutics using immobilized α-1-antitrypsin or SBTI in an ELISA format.

    PubMed

    Braatz, James A; Elias, Christopher; Finny, Joseph G; Tran, Huan; McCaman, Michael

    2015-02-01

    An Enzyme-Linked Immunosorbent Assay (ELISA) has been developed for the quantitation of porcine trypsin as a process residual in cell therapy products based on its capture by either of two immobilized anti-trypsins, α-1-antitrypsin (α1AT) or soybean trypsin inhibitor (SBTI) followed by detection with a polyclonal goat anti-porcine trypsin-IgG conjugated with peroxidase. It was demonstrated that an extended range of antigen quantitation could be achieved that covered nearly three orders of magnitude of trypsin concentration. The utility of the assay was demonstrated by its application to samples generated in a cell-based therapeutic manufacturing setting.

  8. A Quantitative Tool to Distinguish Isobaric Leucine and Isoleucine Residues for Mass Spectrometry-Based De Novo Monoclonal Antibody Sequencing

    NASA Astrophysics Data System (ADS)

    Poston, Chloe N.; Higgs, Richard E.; You, Jinsam; Gelfanova, Valentina; Hale, John E.; Knierman, Michael D.; Siegel, Robert; Gutierrez, Jesus A.

    2014-07-01

    De novo sequencing by mass spectrometry (MS) allows for the determination of the complete amino acid (AA) sequence of a given protein based on the mass difference of detected ions from MS/MS fragmentation spectra. The technique relies on obtaining specific masses that can be attributed to characteristic theoretical masses of AAs. A major limitation of de novo sequencing by MS is the inability to distinguish between the isobaric residues leucine (Leu) and isoleucine (Ile). Incorrect identification of Ile as Leu or vice versa often results in loss of activity in recombinant antibodies. This functional ambiguity is commonly resolved with costly and time-consuming AA mutation and peptide sequencing experiments. Here, we describe a set of orthogonal biochemical protocols, which experimentally determine the identity of Ile or Leu residues in monoclonal antibodies (mAb) based on the selectivity that leucine aminopeptidase shows for n-terminal Leu residues and the cleavage preference for Leu by chymotrypsin. The resulting observations are combined with germline frequencies and incorporated into a logistic regression model, called Predictor for Xle Sites (PXleS) to provide a statistical likelihood for the identity of Leu at an ambiguous site. We demonstrate that PXleS can generate a probability for an Xle site in mAbs with 96% accuracy. The implementation of PXleS precludes the expression of several possible sequences and, therefore, reduces the overall time and resources required to go from spectra generation to a biologically active sequence for a mAb when an Ile or Leu residue is in question.

  9. In situ synchrotron X-ray diffraction analysis of deformation behaviour in Ti-Ni-based thin films.

    PubMed

    Wang, Hong; Sun, Guangai; Wang, Xiaolin; Chen, Bo; Zu, Xiaotao; Liu, Yanping; Li, Liangbin; Pan, Guoqiang; Sheng, Liusi; Liu, Yaoguang; Fu, Yong Qing

    2015-01-01

    Deformation mechanisms of as-deposited and post-annealed Ti50.2Ni49.6, Ti50.3Ni46.2Cu3.5 and Ti48.5Ni40.8Cu7.5 thin films were investigated using the in situ synchrotron X-ray diffraction technique. Results showed that initial crystalline phases determined the deformation mechanisms of all the films during tensile loading. For the films dominated by monoclinic martensites (B19'), tensile stress induced the detwinning of 〈011〉 type-II twins and resulted in the preferred orientations of (002)B19' parallel to the loading direction (∥ LD) and (020)B19' perpendicular to the LD (⊥ LD). For the films dominated by austenite (B2), the austenite directly transformed into martensitic variants (B19') with preferred orientations of (002)B19' ∥ LD and (020)B19' ⊥ LD. For the Ti50.3Ni46.2Cu3.5 and Ti48.1Ni40.8Cu7.5 films, martensitic transformation temperatures decreased apparently after post-annealing because of the large thermal stress generated in the films due to the large differences in thermal expansion coefficients between the film and substrate. PMID:25537586

  10. Modeling of residual stresses by HY-100 weldments

    SciTech Connect

    Zacharia, T.; Taljat, B.; Radhakrishnan, B.

    1997-02-01

    Residual stress distribution in a HY-100 steel disk, induced by GTA spot welding, was analyzed by finite element (FE) formulations and measured by neutron diffraction (ND). Computations used temperature- dependent thermophysical and mechanical properties. FE model predictions are in good agreement with ND data in far heat affected zone (HAZ) and in base metal. Predicted residual stresses in fusion zone and near HAZ were higher than those measured by ND. This discrepancy was attributed to microstructural changes and associated material properties in the HAZ and fusion zone due to phase transformations during the weld thermal cycle.

  11. The force field for imidazolium-based ionic liquids: Novel anions with polar residues

    NASA Astrophysics Data System (ADS)

    Fileti, Eudes Eterno; Chaban, Vitaly V.

    2015-07-01

    Many molecules can be converted into ions via relatively simple procedures. These ions can be combined into ionic liquids (ILs). We develop a new force field (FF) for the seven selected AAILs comprising 1-ethyl-3-methylimidazolium cation and amino acid anions with polar residues. All anions were obtained via deprotonation of carboxyl group in analogy with acetate anion. We account for peculiar interactions between the anion and the cation by fitting electrostatic potential for an ion pair, in contrast to isolated ions. Furthermore, we account for hydrogen bonds obtained via electronic structure consideration. The developed model fosters computational investigation of ionic liquids.

  12. Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings

    DOEpatents

    Pechersky, M.J.

    1999-07-06

    An improved method for measuring residual stress in a material is disclosed comprising the steps of applying a spot of temperature indicating coating to the surface to be studied, establishing a speckle pattern surrounds the spot of coating with a first laser then heating the spot of coating with a far infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress during heating and enables calculation of the stress. 3 figs.

  13. Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings

    DOEpatents

    Pechersky, Martin J.

    1999-01-01

    An improved method for measuring residual stress in a material comprising the steps of applying a spot of temperature indicating coating to the surface to be studied, establishing a speckle pattern surrounds the spot of coating with a first laser then heating the spot of coating with a far infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress during heating and enables calculation of the stress.

  14. Residual Stresses in LENS-Deposited AISI 410 Stainless Steel Plates

    SciTech Connect

    Wang, L; Felicellli, S D; Pratt, Phillip R

    2008-01-01

    The residual stress in thin plate components deposited by the laser engineered net shaping (LENS{reg_sign}) process was investigated experimentally and numerically. Neutron diffraction mapping was used to characterize the residual stress in LENS-deposited AISI 410 stainless steel thin wall plates. Using the commercial welding software SYSWELD, a thermo-mechanical three-dimensional finite element model was developed, which considers also the effect of metallurgical phase transformations. The model was employed to predict the temperature history and the residual stress field during the LENS process. Several simulations were performed with the geometry and process parameters that were used to build the experimental samples. The origin of the residual stress distribution is discussed based on the thermal histories of the samples, and the modeling results are compared with measurements obtained by neutron diffraction mapping.

  15. Assessment of residual stresses on U10Mo alloy based monolithic mini-plates during Hot Isostatic Pressing

    NASA Astrophysics Data System (ADS)

    Ozaltun, Hakan; Herman Shen, M.-H.; Medvedev, Pavel

    2011-12-01

    This article presents an assessment of the residual stresses in U-10 wt.% Mo (U10Mo) alloy based monolithic fuel plates and the elasto-plastic response to thermo-mechanical processing. Monolithic, plate-type fuel is a new fuel form being developed for research and test reactors to achieve higher uranium densities within the reactor core to allow the use of low-enriched uranium fuel in high-performance reactors. Understanding of the three-dimensional residual stress field is important for understanding the in-reactor performance of these plate-type fuels. To define fuel-cladding stress-strain characteristics, a thermo-mechanical finite element model was developed. During fuel plate fabrication, the hot pressing temperature approaches the melting temperature of the cladding, so that temperature dependent material properties were incorporated to improve the accuracy of the model. By using elasto-thermo-plastic material models, it was determined that the cladding material (Al6061-O) is subjected to tensile stresses that exceed its proportional limits. The fuel foil is subject to compressive stresses and remains below yield. The residual stresses in the plates are significant, and therefore, should not be neglected. In particular, the simulations indicate the presence of high stress gradients at the fuel/cladding interface, thus emphasizing the need for a high quality bond.

  16. Optimisation of recovery protocols for double-base smokeless powder residues analysed by total vaporisation (TV) SPME/GC-MS.

    PubMed

    Sauzier, Georgina; Bors, Dana; Ash, Jordan; Goodpaster, John V; Lewis, Simon W

    2016-09-01

    The investigation of explosive events requires appropriate evidential protocols to recover and preserve residues from the scene. In this study, a central composite design was used to determine statistically validated optimum recovery parameters for double-base smokeless powder residues on steel, analysed using total vaporisation (TV) SPME/GC-MS. It was found that maximum recovery was obtained using isopropanol-wetted swabs stored under refrigerated conditions, then extracted for 15min into acetone on the same day as sample collection. These parameters were applied to the recovery of post-blast residues deposited on steel witness surfaces following a PVC pipe bomb detonation, resulting in detection of all target components across the majority of samples. Higher overall recoveries were obtained from plates facing the sides of the device, consistent with the point of first failure occurring in the pipe body as observed in previous studies. The methodology employed here may be readily applied to a variety of other explosive compounds, and thus assist in establishing 'best practice' procedures for explosive investigations. PMID:27343617

  17. ASSESSMENT OF RESIDUAL STRESSES ON U10MO ALLOY BASED MONOLITHIC MINI-PLATES DURING HOT ISOSTATIC PRESSING

    SciTech Connect

    Hakan Ozaltun; M.-H. Herman Shen

    2011-12-01

    This article presents an assessment of the residual stress field on U10Mo alloy based monolithic fuel plates and their elasto-plastic response to the thermo-mechanical fabrication process. Monolithic plate-type fuel for research and test reactors is a new fuel form proposed and developed by Idaho National Laboratory (INL) to accomplish higher uranium densities in the reactor core and allow multi-fold reduction of fuel enrichment. Identification of the 3D residual field is critical for benchmarking the new design and understanding the overall performance of the new plate-type fuels. To define fuel-cladding stress-strain characteristics, a new thermo-mechanical finite element model was developed. Material properties at high temperatures and material plasticity were considered carefully to improve the accuracy as the Hot Pressing temperature reaches the melting temperature of the cladding material. By using elasto-thermo-plastic material models, it was determined that the cladding material (AL6061-TO) is exposed to tensile stress field and exceeds its proportional limits, while the fuel foil (U10Mo) is under compression and remains below its yield limit. It was shown that the residual stresses would govern the overall behavior of the plates, and therefore, should not be neglected. In particular, the simulations have revealed the existence of stress gradients at the fuel/cladding interface, thus emphasizing the necessity of excellent bonding quality at the bond region for mechanical endurance.

  18. Multilayer diffraction grating

    DOEpatents

    Barbee, T.W. Jr.

    1990-04-10

    This invention is for a reflection diffraction grating that functions at X-ray to VUV wavelengths and at normal angles of incidence. The novel grating is comprised of a laminar grating of period D with flat-topped grating bars. A multiplicity of layered synthetic microstructures, of period d and comprised of alternating flat layers of two different materials, are disposed on the tops of the grating bars of the laminar grating. In another embodiment of the grating, a second multiplicity of layered synthetic microstructures are also disposed on the flat faces, of the base of the grating, between the bars. D is in the approximate range from 3,000 to 50,000 Angstroms, but d is in the approximate range from 10 to 400 Angstroms. The laminar grating and the layered microstructures cooperatively interact to provide many novel and beneficial instrumentational advantages. 2 figs.

  19. Multilayer diffraction grating

    DOEpatents

    Barbee, Jr., Troy W.

    1990-01-01

    This invention is for a reflection diffraction grating that functions at X-ray to VUV wavelengths and at normal angles of incidence. The novel grating is comprised of a laminar grating of period D with flat-topped grating bars. A multiplicity of layered synthetic microstructures, of period d and comprised of alternating flat layers of two different materials, are disposed on the tops of the grating bars of the laminar grating. In another embodiment of the grating, a second multiplicity of layered synthetic microstructures are also disposed on the flat faces, of the base of the grating, between the bars. D is in the approximate range from 3,000 to 50,000 Angstroms, but d is in the approximate range from 10 to 400 Angstroms. The laminar grating and the layered microstructures cooperatively interact to provide many novel and beneficial instrumentational advantages.

  20. Electromagnetic diffraction efficiencies for plane reflection diffraction gratings

    NASA Technical Reports Server (NTRS)

    Marathay, A. S.; Shrode, T. E.

    1974-01-01

    The theory and computer programs, based on electromagnetic theory, for the analysis and design of echelle gratings were developed. The gratings are designed for instruments that operate in the ultraviolet portion of the spectrum. The theory was developed so that the resulting computer programs will be able to analyze deep (up to 30 wavelengths) gratings by including as many as 100 real or homogeneous diffraction orders. The program calculates the complex amplitude coefficient for each of the diffracted orders. A check on the numerical method used to solve the integral equations is provided by a conservation of energy calculation.

  1. Rate and determinants of residual viremia in multidrug-experienced patients successfully treated with raltegravir-based regimens.

    PubMed

    Baroncelli, Silvia; Pirillo, Maria Franca; Galluzzo, Clementina Maria; Antoni, Anna Degli; Ladisa, Nicoletta; Francisci, Daniela; d'Ettorre, Gabriella; Segala, Daniela; Vivarelli, Angela; Sozio, Federica; Cirioni, Oscar; Weimer, Liliana Elena; Fragola, Vincenzo; Parruti, Giustino; Floridia, Marco

    2015-01-01

    Residual HIV viremia, defined by low levels of plasma HIV RNA with enhanced-sensitivity assays, may persist even in the presence of successful antiretroviral therapy, but little is known about its determinants. Our objective was to evaluate the rate and determinants of residual viremia in patients who show stable undetectable plasma HIV-1 RNA with conventional assays. Forty-four multidrug-experienced patients with undetectable levels of HIV RNA for at least 2 years under raltegravir-based regimens were evaluated. An ultrasensitive (2.5 copies/ml) real-time PCR method was used to quantify plasma HIV RNA. After 12 months of salvage treatment, 48.3% of the patients had residual viremia between 2.5 and 37 copies/ml. The proportion of patients with plasma HIV RNA below 2.5 copies/ml decreased from 51.7% at 12 months to 30.8% at 24 months. The presence of residual viremia was not associated with levels of viremia before starting raltegravir. Considering CD4 counts, hepatitis B or C virus (HBV or HCV) coinfection, or other demographic characteristics, for the time interval between HIV diagnosis and initiation of antiretroviral therapy, patients with a longer interval (>1 year) were significant less likely to have RNA levels below 2.5 copies/ml at 12 months compared to patients who started therapy within 1 year of HIV diagnosis (28.6% vs. 73.3%, p=0.027). Half of the patients showing undetectable HIV viremia with conventional assays had low-level viremia with ultrasensitive assays, with no predictive role of viroimmunological status at the start of the regimen. The potential influence of the interval between HIV diagnosis and initiation of treatment should be confirmed in subjects with a known date of seroconversion. PMID:25092266

  2. Hard Diffraction at CDF

    SciTech Connect

    Melese, P.; CDF Collaboration

    1997-06-01

    We present results on diffractive production of hard processes in {anti p}p collisions at {radical}s = 1.8 TeV at the Tevatron using the CDF detector. The signatures used to identify diffractive events are the forward rapidity gap and/or the detection of a recoil antiproton with high forward momentum. We have observed diffractive W- boson, dijet, and heavy quark production. We also present results on double-pomeron production of dijets.

  3. Determination of γ-γ' lattice misfit in a single-crystal nickel-based superalloy using convergent beam electron diffraction aided by finite element calculations.

    PubMed

    Brunetti, G; Settefrati, A; Hazotte, A; Denis, S; Fundenberger, J-J; Tidu, A; Bouzy, E

    2012-02-01

    In single-crystal nickel-based superalloys, the lattice mismatch associated with interface coherency between γ matrix and γ' precipitates has a strong influence on mechanical properties. The unconstrained lattice misfit in a single-crystal of the MC2 nickel-based superalloy is determined using convergent beam electron diffraction measurements and finite element calculations. The apparent lattice parameters of both constrained phases are obtained in thin foils, using a new multi-pattern approach, which allows for unambiguous determination of all the lattice parameters considering the real symmetry of the strained crystals. Finite element calculations are used to establish relations between the constrained and unconstrained lattice parameters, with the stress relaxation resulting from the thin foil geometry taken into account. PMID:22055767

  4. Determination of γ-γ' lattice misfit in a single-crystal nickel-based superalloy using convergent beam electron diffraction aided by finite element calculations.

    PubMed

    Brunetti, G; Settefrati, A; Hazotte, A; Denis, S; Fundenberger, J-J; Tidu, A; Bouzy, E

    2012-02-01

    In single-crystal nickel-based superalloys, the lattice mismatch associated with interface coherency between γ matrix and γ' precipitates has a strong influence on mechanical properties. The unconstrained lattice misfit in a single-crystal of the MC2 nickel-based superalloy is determined using convergent beam electron diffraction measurements and finite element calculations. The apparent lattice parameters of both constrained phases are obtained in thin foils, using a new multi-pattern approach, which allows for unambiguous determination of all the lattice parameters considering the real symmetry of the strained crystals. Finite element calculations are used to establish relations between the constrained and unconstrained lattice parameters, with the stress relaxation resulting from the thin foil geometry taken into account.

  5. Water based microwave assisted extraction of thiamethoxam residues from vegetables and soil for determination by HPLC.

    PubMed

    Karmakar, Rajib; Singh, Shashi Bala; Kulshrestha, Gita

    2012-02-01

    A microwave assisted extraction (MAE) method for determination of thiamethoxam residues in vegetable and soil samples was standardized. Insecticide spiked vegetable and soil samples were extracted by MAE using water as an extraction solvent, cleaned up by solid phase extraction and analysed by high performance liquid chromatography on photodiode array detector. The recoveries of the insecticide from various vegetable (tomato, radish, brinjal, okra, French been, sugarbeet) and soil (sandy loam, silty clay loam, sandy clay loam, loamy sand) samples at 0.1 and 0.5 μg g(-1) spiking levels ranged from 79.8% to 86.2% and from 82.1% to 87.0%, respectively. The recoveries by MAE were comparable to those obtained by the conventional blender and shake-flask extraction techniques. The precision of the MAE method was demonstrated by relative standard deviations of <3% for the insecticide.

  6. Immunology-Based Techniques for the Detection of Veterinary Drug Residues in Foods

    NASA Astrophysics Data System (ADS)

    Reig, Milagro; Toldrá, Fidel

    Veterinary drugs are used in farm animals, via the feed or the drinking water, to prevent the outbreak of diseases or even for the treatment of diseases. However, the growth of animals may be promoted through the use of hormones and antibiotics. Depending on the type of residue and the application and washing conditions, these substances or its metabolites may remain in meat and other foods of animal origin and may cause adverse effects on consumers’ health. This is the main reason why its use is strictly regulated or even banned (case of the European Union) in different countries. Antibiotics typically used for growth promotion include chloramphenicol, nitrofurans, and enrofloxacin but others like sulphonamides, macrolides etc. may also be used (Reig & Toldrá, 2007).

  7. Cl app: android-based application program for monitoring the residue chlorine in water

    NASA Astrophysics Data System (ADS)

    Intaravanne, Yuttana; Sumriddetchkajorn, Sarun; Porntheeraphat, Supanit; Chaitavon, Kosom; Vuttivong, Sirajit

    2015-07-01

    A farmer usually uses a cheap chemical material called chlorine to destroy the cell structure of unwanted organisms and remove some plant effluents in a baby shrimp farm. A color changing of the reaction between chlorine and chemical indicator is used to monitor the residue chlorine in water before releasing a baby shrimp into a pond. To get rid of the error in color reading, our previous works showed how a smartphone can be functioned as a color reader for estimating the chlorine concentration in water. In this paper, we show the improvement of interior configuration of our prototype and the distribution to several baby shrimp farms. In the future, we plan to make it available worldwide through the online market as well as to develop more application programs for monitoring other chemical substances.

  8. Analysis of nanometer-isolated trench diffract aerial image of both conventional and second-generation synchrotron-based proximity x-ray lithography

    NASA Astrophysics Data System (ADS)

    Xie, Changqing; Chen, Dapeng; Liu, Ming; Ye, Tianchun; Yi, Futing

    2005-01-01

    In this paper, Beam Propagation Method (BPM) with Fast Fourier Transforms(FFT) is employed to efficiently calculate the diffract image in the wafer plane for both conventional and second generation synchrotron-based proximity x-ray lithography(PXL). In the simulation, a dark-field isolated space pattern silicon nitride/Ta x-ray mask is used for conventional PXL and a diamond /Ta x-ray mask is used for second generation PXL, the diffract image"s dependency on absorber thickness, mask-wafer gap, effective total blur, linewidth and absorber sidewall slope has been numerically evaluated. For conventional PXL, in order to obtain a isolated trench resolution of 50nm, the mask-wafer gap should be controlled below 5 micron, the optimization condition is mask-wafer gap 5 micron, Ta absorber thickness 300nm, effective total blur 10nm, absorber sidewall slope 3°, the corresponding aerial image contrast is 0.457; For second generation, in order to obtain a isolated trench resolution of 50nm, the mask-wafer gap can be as large as 10 micron. In order to obtain a isolated trench resolution of 35nm, mask-wafer gap should be controlled below 5 micron.

  9. Monoclonal antibody-based immunoassays for cyprodinil residue analysis in QuEChERS-based fruit extracts.

    PubMed

    Esteve-Turrillas, Francesc A; Abad-Somovilla, Antonio; Quiñones-Reyes, Guillermo; Agulló, Consuelo; Mercader, Josep V; Abad-Fuentes, Antonio

    2015-11-15

    Cyprodinil is among the most common agrochemical residues found in highly perishable fruits, such as strawberries. In the present study, high-affinity monoclonal antibodies to this anilinopyrimidine fungicide were raised for the first time with the aim to produce valuable immunochemical analytical assays. Cyprodinil bioconjugates and the generated novel monoclonal antibodies were employed for sensitive competitive immunoassay development in two different formats. The limits of detection of the optimized assays were 20 and 30 ng L(-1) for the indirect and direct assay, respectively. Influence over assay parameters of different physicochemical factors was studied. Strawberry samples were extracted following the recommended QuEChERS procedure for pesticide residues in food, and analyzed by the optimized immunoassays. Recoveries and coefficients of variation from fortified samples were within standard values. In addition, the obtained immunochemical results with naturally contaminated samples were statistically comparable, according to Deming regression analysis, to those of a reference chromatographic method.

  10. Single Photon diffraction and interference

    NASA Astrophysics Data System (ADS)

    Hodge, John

    2015-04-01

    A previous paper based on the Scalar Theory of Everything studied photon diffraction and interference (IntellectualArchive, Vol.1, No. 3, P. 20, Toronto, Canada July 2012. http://intellectualarchive.com/?link=item&id=597). Several photons were required in the experiment at the same time. Interference experiments with one photon in the experiment at a time also showed interference patterns. The previous paper with the Bohm Interpretation, models of the screen and mask, and the Transaction Interpretation of Quantum Mechanics were combined. The reverse wave required by the Transaction Interpretation was provided by a reflected plenum wave rather than a reverse time wave. The speed of the plenum wave was assumed to be much faster than the speed of photons/light. Using the assumptions of Fraunhofer diffraction resulted in the same equation for the photon distribution on a screen as the intensity pattern of the Fraunhofer diffraction. (http://myplace.frontier.com/ ~ jchodge/)

  11. Fraunhofer diffraction of light by human enamel.

    PubMed

    O'Brien, W J

    1988-02-01

    Fraunhofer diffraction patterns of human enamel samples were photographed with a helium-neon laser beam (lambda = 633 nm). The first-order diffraction angle was in reasonable agreement with a prediction based upon enamel prisms acting as a two-dimensional grating. These results support the hypothesis that enamel diffracts light because of the periodic structure of enamel prisms with interprismatic spaces, which act as slits.

  12. Aircraft noise propagation. [sound diffraction by wings

    NASA Technical Reports Server (NTRS)

    Hadden, W. J.; Pierce, A. D.

    1978-01-01

    Sound diffraction experiments conducted at NASA Langley Research Center to study the acoustical implications of the engine over wing configuration (noise-shielding by wing) and to provide a data base for assessing various theoretical approaches to the problem of aircraft noise reduction are described. Topics explored include the theory of sound diffraction around screens and wedges; the scattering of spherical waves by rectangular patches; plane wave diffraction by a wedge with finite impedence; and the effects of ambient flow and distribution sources.

  13. Phononic crystal diffraction gratings

    NASA Astrophysics Data System (ADS)

    Moiseyenko, Rayisa P.; Herbison, Sarah; Declercq, Nico F.; Laude, Vincent

    2012-02-01

    When a phononic crystal is interrogated by an external source of acoustic waves, there is necessarily a phenomenon of diffraction occurring on the external enclosing surfaces. Indeed, these external surfaces are periodic and the resulting acoustic diffraction grating has a periodicity that depends on the orientation of the phononic crystal. This work presents a combined experimental and theoretical study on the diffraction of bulk ultrasonic waves on the external surfaces of a 2D phononic crystal that consists of a triangular lattice of steel rods in a water matrix. The results of transmission experiments are compared with theoretical band structures obtained with the finite-element method. Angular spectrograms (showing frequency as a function of angle) determined from diffraction experiments are then compared with finite-element simulations of diffraction occurring on the surfaces of the crystal. The experimental results show that the diffraction that occurs on its external surfaces is highly frequency-dependent and has a definite relation with the Bloch modes of the phononic crystal. In particular, a strong influence of the presence of bandgaps and deaf bands on the diffraction efficiency is found. This observation opens perspectives for the design of efficient phononic crystal diffraction gratings.

  14. Elemental and mineralogical study of earth-based pigments using particle induced X-ray emission and X-ray diffraction

    NASA Astrophysics Data System (ADS)

    Nel, P.; Lynch, P. A.; Laird, J. S.; Casey, H. M.; Goodall, L. J.; Ryan, C. G.; Sloggett, R. J.

    2010-07-01

    Artwork and precious artefacts demand non-destructive analytical methodologies for art authentication, attribution and provenance assessment. However, structural and chemical characterisation represents a challenging problem with existing analytical techniques. A recent authentication case based on an Australian Aboriginal artwork, indicate there is substantial benefit in the ability of particle induced X-ray emission (PIXE), coupled with dynamic analysis (DA) to characterise pigments through trace element analysis. However, this information alone is insufficient for characterising the mineralogical residence of trace elements. For this reason a combined methodology based on PIXE and X-ray diffraction (XRD) has been performed to explore the benefits of a more comprehensive data set. Many Aboriginal paintings and artefacts are predominantly earth pigment based. This makes these cultural heritage materials an ideal case study for testing the above combined methodological approach on earth-based pigments. Samples of synthetic and naturally occurring earth-based pigments were obtained from a range of sources, which include Indigenous communities within Australia's Kimberley region. PIXE analyses using a 3 MeV focussed proton beam at the CSIRO nuclear microprobe, as well as laboratory-based XRD was carried out on the above samples. Elemental signature spectra as well as mineralogical data were used to assess issues regarding synthetic and naturally occurring earth pigments with the ultimate aim of establishing provenance.

  15. Pesticide residue analysis in cereal-based baby foods using multi-walled carbon nanotubes dispersive solid-phase extraction.

    PubMed

    González-Curbelo, Miguel Angel; Asensio-Ramos, María; Herrera-Herrera, Antonio V; Hernández-Borges, Javier

    2012-07-01

    In the present study, a new analytical method has been developed for the simultaneous quantification of 15 organophosphorus pesticides, including some of their metabolites, (disulfoton-sulfoxide, ethoprophos, cadusafos, dimethoate, terbufos, disulfoton, chlorpyrifos-methyl, malaoxon, fenitrothion, pirimiphos-methyl, malathion, chlorpyrifos, terbufos-sulfone, disulfoton-sulfone and fensulfothion) in three different types of commercial cereal-based baby foods. Dispersive solid-phase extraction (dSPE) with multi-walled carbon nanotubes (MWCNTs) was used together with gas chromatography with nitrogen phosphorus detection. Most favorable conditions involved a previous ultrasound-assisted extraction of the sample with acetonitrile containing formic acid. After evaporation of the extract and redissolution in water, a dSPE procedure was carried out with MWCNTs. The whole method was validated in terms of repeatability, linearity, precision and accuracy and matrix effect was also evaluated. Absolute recoveries were in the range 64-105 % with relative standard deviation values below 7.6 %. Limits of quantification achieved ranged from 0.31 to 5.50 μg/kg, which were lower than the European Union maximum residue limits for pesticide residues in cereal-based baby foods. PMID:22623047

  16. Direct sample positioning and alignment methodology for strain measurement by diffraction

    NASA Astrophysics Data System (ADS)

    Ratel, N.; Hughes, D. J.; King, A.; Malard, B.; Chen, Z.; Busby, P.; Webster, P. J.

    2005-05-01

    An ISO (International Organization for Standardization) TTA (Technology Trends Assessment) was published in 2001 for the determination of residual stress using neutron diffraction which identifies sample alignment and positioning as a key source of strain measurement error. Although the measurement uncertainty by neutron and synchrotron x-ray diffraction for an individual measurement of lattice strain is typically of the order of 10-100×10-6, specimens commonly exhibit strain gradients of 1000×10-6mm-1 or more, making sample location a potentially considerable source of error. An integrated approach to sample alignment and positioning is described which incorporates standard base-plates and sample holders, instrument alignment procedures, accurate digitization using a coordinate measuring machine and automatic generation of instrument control scripts. The methodology that has been developed is illustrated by the measurement of the transverse residual strain field in a welded steel T-joint using neutrons.

  17. Direct sample positioning and alignment methodology for strain measurement by diffraction

    SciTech Connect

    Ratel, N.; Hughes, D.J.; King, A.; Malard, B.; Chen, Z.; Busby, P.; Webster, P.J.

    2005-05-15

    An ISO (International Organization for Standardization) TTA (Technology Trends Assessment) was published in 2001 for the determination of residual stress using neutron diffraction which identifies sample alignment and positioning as a key source of strain measurement error. Although the measurement uncertainty by neutron and synchrotron x-ray diffraction for an individual measurement of lattice strain is typically of the order of 10-100x10{sup -6}, specimens commonly exhibit strain gradients of 1000x10{sup -6} mm{sup -1} or more, making sample location a potentially considerable source of error. An integrated approach to sample alignment and positioning is described which incorporates standard base-plates and sample holders, instrument alignment procedures, accurate digitization using a coordinate measuring machine and automatic generation of instrument control scripts. The methodology that has been developed is illustrated by the measurement of the transverse residual strain field in a welded steel T-joint using neutrons.

  18. Polylactide-based renewable composites from natural products residues by encapsulated film bag: characterization and biodegradability.

    PubMed

    Wu, Chin-San

    2012-09-01

    In the present study, the biodegradability, morphology, and mechanical properties of composite materials consisting of acrylic acid-grafted polylactide (PLA-g-AA) and natural products residues (corn starch, CS) were evaluated. Composites containing acrylic acid-grafted PLA (PLA-g-AA/CS) exhibited noticeably superior mechanical properties due to their greater compatibility with CS compared with PLA/CS. The feasibility of using PLA-g-AA/CS as a film bag material to facilitate the controlled release of an encapsulated phosphate-solubilizing bacterium (PSB) Burkholderia cepacia as a fertilizer use promoter was then evaluated. For purposes of comparison and accurate characterization, a PLA film bag was also assessed. The results showed that the bacterium completely degraded both the PLA and the PLA-g-AA/CS composite film bags, resulting in cell release. The PLA-g-AA/CS (20 wt%) film bags were more biodegradable than those made of PLA, and displayed a higher loss of molecular weight and intrinsic viscosity, indicating a strong connection between these characteristics and biodegradability. PMID:24751080

  19. Polylactide-based renewable composites from natural products residues by encapsulated film bag: characterization and biodegradability.

    PubMed

    Wu, Chin-San

    2012-09-01

    In the present study, the biodegradability, morphology, and mechanical properties of composite materials consisting of acrylic acid-grafted polylactide (PLA-g-AA) and natural products residues (corn starch, CS) were evaluated. Composites containing acrylic acid-grafted PLA (PLA-g-AA/CS) exhibited noticeably superior mechanical properties due to their greater compatibility with CS compared with PLA/CS. The feasibility of using PLA-g-AA/CS as a film bag material to facilitate the controlled release of an encapsulated phosphate-solubilizing bacterium (PSB) Burkholderia cepacia as a fertilizer use promoter was then evaluated. For purposes of comparison and accurate characterization, a PLA film bag was also assessed. The results showed that the bacterium completely degraded both the PLA and the PLA-g-AA/CS composite film bags, resulting in cell release. The PLA-g-AA/CS (20 wt%) film bags were more biodegradable than those made of PLA, and displayed a higher loss of molecular weight and intrinsic viscosity, indicating a strong connection between these characteristics and biodegradability.

  20. Nearly diffraction-limited X-ray focusing with variable-numerical-aperture focusing optical system based on four deformable mirrors.

    PubMed

    Matsuyama, Satoshi; Nakamori, Hiroki; Goto, Takumi; Kimura, Takashi; Khakurel, Krishna P; Kohmura, Yoshiki; Sano, Yasuhisa; Yabashi, Makina; Ishikawa, Tetsuya; Nishino, Yoshinori; Yamauchi, Kazuto

    2016-01-01

    Unlike the electrostatic and electromagnetic lenses used in electron microscopy, most X-ray focusing optical systems have fixed optical parameters with constant numerical apertures (NAs). This lack of adaptability has significantly limited application targets. In the research described herein, we developed a variable-NA X-ray focusing system based on four deformable mirrors, two sets of Kirkpatrick-Baez-type focusing mirrors, in order to control the focusing size while keeping the position of the focus unchanged. We applied a mirror deformation procedure using optical/X-ray metrology for offline/online adjustments. We performed a focusing test at a SPring-8 beamline and confirmed that the beam size varied from 108 nm to 560 nm (165 nm to 1434 nm) in the horizontal (vertical) direction by controlling the NA while maintaining diffraction-limited conditions. PMID:27097853

  1. Chemical disorder determines the deviation of the Slater-Pauling rule for Fe2MnSi-based Heusler alloys: evidences from neutron diffraction and density functional theory.

    PubMed

    Tedesco, J C G; Pedro, S S; Caraballo Vivas, R J; Cruz, C; Andrade, V M; Dos Santos, A M; Carvalho, A M G; Costa, M; Venezuela, P; Rocco, D L; Reis, M S

    2016-11-30

    Fe2MnSi fails to follow the Slater-Pauling rule. This phenomenon is thought to originate from either: (i) an antiferromagnetic arrangement of Mn ions at low temperature and/or (ii) chemical disorder. An important insight on this issue could be achieved by considering Fe2MnSi1-x Ga x compounds, thoroughly studied here by means of magnetization, neutron diffraction and density functional calculations (DFT). Our results indicate that chemical disorder (and not the antiferromagnetic arrangement) is responsible for the deviation of the Slater-Pauling rule on Fe2MnSi-based Heusler alloys. Furthermore, evidences suggest that Ga substitution into Si site favors the Fe/Mn disorder, further enhancing the observed deviation. PMID:27633814

  2. Determination of In concentration in pseudomorphic InxGa1-xN quantum wells based on convergent-beam electron diffraction

    NASA Astrophysics Data System (ADS)

    Stirman, J. N.; Takeguchi, M.; McCartney, M. R.; Smith, David J.

    2004-01-01

    An approach based on the technique of convergent-beam electron diffraction (CBED) has been used to determine the elemental composition of a pseudomorphic GaN/InxGa1-xN/GaN quantum-well structure on the nanometer scale. Areas of triangles formed by intersecting higher order Laue-zone (HOLZ) lines are highly sensitive to lattice-parameter variations. By calculating the ratio of triangle areas, the local In concentration is estimated to within ±0.5% once lattice expansion in the growth direction has been taken into account. Moreover, shifts in the HOLZ-line positions as the CBED probe is moved along the quantum well provide a simple and rapid indication of local fluctuations in In content. The technique is applicable to other pseudomorphically strained epitaxial layers.

  3. Chemical disorder determines the deviation of the Slater-Pauling rule for Fe2MnSi-based Heusler alloys: evidences from neutron diffraction and density functional theory.

    PubMed

    Tedesco, J C G; Pedro, S S; Caraballo Vivas, R J; Cruz, C; Andrade, V M; Dos Santos, A M; Carvalho, A M G; Costa, M; Venezuela, P; Rocco, D L; Reis, M S

    2016-11-30

    Fe2MnSi fails to follow the Slater-Pauling rule. This phenomenon is thought to originate from either: (i) an antiferromagnetic arrangement of Mn ions at low temperature and/or (ii) chemical disorder. An important insight on this issue could be achieved by considering Fe2MnSi1-x Ga x compounds, thoroughly studied here by means of magnetization, neutron diffraction and density functional calculations (DFT). Our results indicate that chemical disorder (and not the antiferromagnetic arrangement) is responsible for the deviation of the Slater-Pauling rule on Fe2MnSi-based Heusler alloys. Furthermore, evidences suggest that Ga substitution into Si site favors the Fe/Mn disorder, further enhancing the observed deviation.

  4. Substrate surface effect on the structure of cubic BN thin films from synchrotron-based X-ray diffraction and reflection

    NASA Astrophysics Data System (ADS)

    Zhang, X. M.; Wen, W.; Li, X. L.; He, Q.; Zhou, X. T.

    2013-02-01

    Cubic BN (cBN) thin films prepared by mass-selected ion beam deposition technique (MSIBD) on Si substrates with different surface roughness were studied by synchrotron-based grazing incidence X-ray diffraction (GI-XRD) and X-ray reflectivity (XRR) measurements. The BN films are mostly composed of two phases. One is cBN phase, the other is hexagonal BN (hBN) phase. The cubic phase content of the thin films is dependent on the roughness of their corresponding substrates. The smooth substrate surface is helpful for the nucleation of the cBN phase. cBN phase is mostly grown in the near surface region of the films and there is a hBN interlayer at the film-substrate interface. GIXRD and XRR are proved to be powerful tools for analyzing the structure of the cBN thin films.

  5. Nearly diffraction-limited X-ray focusing with variable-numerical-aperture focusing optical system based on four deformable mirrors

    PubMed Central

    Matsuyama, Satoshi; Nakamori, Hiroki; Goto, Takumi; Kimura, Takashi; Khakurel, Krishna P.; Kohmura, Yoshiki; Sano, Yasuhisa; Yabashi, Makina; Ishikawa, Tetsuya; Nishino, Yoshinori; Yamauchi, Kazuto

    2016-01-01

    Unlike the electrostatic and electromagnetic lenses used in electron microscopy, most X-ray focusing optical systems have fixed optical parameters with constant numerical apertures (NAs). This lack of adaptability has significantly limited application targets. In the research described herein, we developed a variable-NA X-ray focusing system based on four deformable mirrors, two sets of Kirkpatrick–Baez-type focusing mirrors, in order to control the focusing size while keeping the position of the focus unchanged. We applied a mirror deformation procedure using optical/X-ray metrology for offline/online adjustments. We performed a focusing test at a SPring-8 beamline and confirmed that the beam size varied from 108 nm to 560 nm (165 nm to 1434 nm) in the horizontal (vertical) direction by controlling the NA while maintaining diffraction-limited conditions. PMID:27097853

  6. Nearly diffraction-limited X-ray focusing with variable-numerical-aperture focusing optical system based on four deformable mirrors

    NASA Astrophysics Data System (ADS)

    Matsuyama, Satoshi; Nakamori, Hiroki; Goto, Takumi; Kimura, Takashi; Khakurel, Krishna P.; Kohmura, Yoshiki; Sano, Yasuhisa; Yabashi, Makina; Ishikawa, Tetsuya; Nishino, Yoshinori; Yamauchi, Kazuto

    2016-04-01

    Unlike the electrostatic and electromagnetic lenses used in electron microscopy, most X-ray focusing optical systems have fixed optical parameters with constant numerical apertures (NAs). This lack of adaptability has significantly limited application targets. In the research described herein, we developed a variable-NA X-ray focusing system based on four deformable mirrors, two sets of Kirkpatrick-Baez-type focusing mirrors, in order to control the focusing size while keeping the position of the focus unchanged. We applied a mirror deformation procedure using optical/X-ray metrology for offline/online adjustments. We performed a focusing test at a SPring-8 beamline and confirmed that the beam size varied from 108 nm to 560 nm (165 nm to 1434 nm) in the horizontal (vertical) direction by controlling the NA while maintaining diffraction-limited conditions.

  7. Nearly diffraction-limited X-ray focusing with variable-numerical-aperture focusing optical system based on four deformable mirrors.

    PubMed

    Matsuyama, Satoshi; Nakamori, Hiroki; Goto, Takumi; Kimura, Takashi; Khakurel, Krishna P; Kohmura, Yoshiki; Sano, Yasuhisa; Yabashi, Makina; Ishikawa, Tetsuya; Nishino, Yoshinori; Yamauchi, Kazuto

    2016-04-21

    Unlike the electrostatic and electromagnetic lenses used in electron microscopy, most X-ray focusing optical systems have fixed optical parameters with constant numerical apertures (NAs). This lack of adaptability has significantly limited application targets. In the research described herein, we developed a variable-NA X-ray focusing system based on four deformable mirrors, two sets of Kirkpatrick-Baez-type focusing mirrors, in order to control the focusing size while keeping the position of the focus unchanged. We applied a mirror deformation procedure using optical/X-ray metrology for offline/online adjustments. We performed a focusing test at a SPring-8 beamline and confirmed that the beam size varied from 108 nm to 560 nm (165 nm to 1434 nm) in the horizontal (vertical) direction by controlling the NA while maintaining diffraction-limited conditions.

  8. Chemical disorder determines the deviation of the Slater-Pauling rule for Fe2MnSi-based Heusler alloys: evidences from neutron diffraction and density functional theory

    NASA Astrophysics Data System (ADS)

    Tedesco, J. C. G.; Pedro, S. S.; Caraballo Vivas, R. J.; Cruz, C.; Andrade, V. M.; dos Santos, A. M.; Carvalho, A. M. G.; Costa, M.; Venezuela, P.; Rocco, D. L.; Reis, M. S.

    2016-11-01

    Fe2MnSi fails to follow the Slater-Pauling rule. This phenomenon is thought to originate from either: (i) an antiferromagnetic arrangement of Mn ions at low temperature and/or (ii) chemical disorder. An important insight on this issue could be achieved by considering Fe2MnSi1-x Ga x compounds, thoroughly studied here by means of magnetization, neutron diffraction and density functional calculations (DFT). Our results indicate that chemical disorder (and not the antiferromagnetic arrangement) is responsible for the deviation of the Slater-Pauling rule on Fe2MnSi-based Heusler alloys. Furthermore, evidences suggest that Ga substitution into Si site favors the Fe/Mn disorder, further enhancing the observed deviation.

  9. Validation of a QuEChERS-based gas chromatographic method for analysis of pesticide residues in Cassia angustifolia (senna).

    PubMed

    Tripathy, Vandana; Saha, Ajoy; Patel, Dilipkumar J; Basak, B B; Shah, Paresh G; Kumar, Jitendra

    2016-08-01

    A simple multi-residue method based on modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) approach was established for the determination of 17 organochlorine (OC), 15 organophosphorous (OP) and 7 synthetic pyrethroid (SP) pesticides in an economically important medicinal plant of India, Senna (Cassia angustifolia), by gas chromatography coupled to electron capture and flame thermionic detectors (GC/ECD/FTD) and confirmation of residues was done on gas chromatograph coupled with mass spectrometry (GC-MS). The developed method was validated by testing the following parameters: linearity, limit of detection (LOD), limit of quantification (LOQ), matrix effect, accuracy-precision and measurement uncertainty; the validation study clearly demonstrated the suitability of the method for its intended application. All pesticides showed good linearity in the range 0.01-1.0 μg mL(-1) for OCs and OPs and 0.05-2.5 μg mL(-1) for SPs with correlation coefficients higher than 0.98. The method gave good recoveries for most of the pesticides (70-120%) with intra-day and inter-day precision < 20% in most of the cases. The limits of detection varied from 0.003 to 0.03 mg kg(-1), and the LOQs were determined as 0.01-0.049 mg kg(-1). The expanded uncertainties were <30%, which was distinctively less than a maximum default value of ±50%. The proposed method was successfully applied to determine pesticide residues in 12 commercial market samples obtained from different locations in India. PMID:27153296

  10. Phonons from neutron powder diffraction

    SciTech Connect

    Dimitrov, D.A.; Louca, D.; Roeder, H. )

    1999-09-01

    The spherically averaged structure function S([vert bar][bold q][vert bar]) obtained from pulsed neutron powder diffraction contains both elastic and inelastic scattering via an integral over energy. The Fourier transformation of S([vert bar][bold q][vert bar]) to real space, as is done in the pair density function (PDF) analysis, regularizes the data, i.e., it accentuates the diffuse scattering. We present a technique which enables the extraction of off-center ([vert bar][bold q][vert bar][ne]0) phonon information from powder diffraction experiments by comparing the experimental PDF with theoretical calculations based on standard interatomic potentials and the crystal symmetry. This procedure [dynamics from powder diffraction] has been [ital successfully] implemented as demonstrated here for two systems, a simple metal fcc Ni and an ionic crystal CaF[sub 2]. Although computationally intensive, this data analysis allows for a phonon based modeling of the PDF, and additionally provides off-center phonon information from neutron powder diffraction. [copyright] [ital 1999] [ital The American Physical Society

  11. Numerical Parametric Analysis of Bond Coat Thickness Effect on Residual Stresses in Zirconia-Based Thermal Barrier Coatings

    NASA Astrophysics Data System (ADS)

    Abbas, Musharaf; Hasham, Hasan Junaid; Baig, Yasir

    2016-02-01

    Numerical-based finite element investigation has been conducted to explain the effect of bond coat thickness on stress distribution in traditional and nanostructured yttria-stabilized zirconia (YSZ)-based thermal barrier coatings (TBC). Stress components have been determined to quantitatively analyze the mechanical response of both kinds of coatings under the thermal shock effect. It has been found that maximum radial tensile and compressive stresses that exist at thermally grown oxide (TGO)/bond coat interface and within TGO respectively decrease with an increase in bond coat thickness. Effect of bond coat thickness on axial tensile stresses is not significant. However, axial compressive stresses that exist at the edge of the specimen near bond coat/substrate interface decrease appreciably with the increase in bond coat thickness. Residual stress profile as a function of bond coat thickness is further explained for comparative analysis of both coatings to draw some useful conclusions helpful in failure studies of TBCs.

  12. Parametric Powder Diffraction

    NASA Astrophysics Data System (ADS)

    David, William I. F.; Evans, John S. O.

    The rapidity with which powder diffraction data may be collected, not only at neutron and X-ray synchrotron facilities but also in the laboratory, means that the collection of a single diffraction pattern is now the exception rather than the rule. Many experiments involve the collection of hundreds and perhaps many thousands of datasets where a parameter such as temperature or pressure is varied or where time is the variable and life-cycle, synthesis or decomposition processes are monitored or three-dimensional space is scanned and the three-dimensional internal structure of an object is elucidated. In this paper, the origins of parametric diffraction are discussed and the techniques and challenges of parametric powder diffraction analysis are presented. The first parametric measurements were performed around 50 years ago with the development of a modified Guinier camera but it was the automation afforded by neutron diffraction combined with increases in computer speed and memory that established parametric diffraction on a strong footing initially at the ILL, Grenoble in France. The theoretical parameterisation of quantities such as lattice constants and atomic displacement parameters will be discussed and selected examples of parametric diffraction over the past 20 years will be reviewed that highlight the power of the technique.

  13. A flexible method for residual stress measurement of spray coated layers by laser made hole drilling and SLM based beam steering

    NASA Astrophysics Data System (ADS)

    Osten, W.; Pedrini, G.; Weidmann, P.; Gadow, R.

    2015-08-01

    A minimum invasive but high resolution method for residual stress analysis of ceramic coatings made by thermal spraycoating using a pulsed laser for flexible hole drilling is described. The residual stresses are retrieved by applying the measured surface data for a model-based reconstruction procedure. While the 3D deformations and the profile of the machined area are measured with digital holography, the residual stresses are calculated by FE analysis. To improve the sensitivity of the method, a SLM is applied to control the distribution and the shape of the holes. The paper presents the complete measurement and reconstruction procedure and discusses the advantages and challenges of the new technology.

  14. Comparison of risk-based versus random sampling in the monitoring of antimicrobial residues in Danish finishing pigs.

    PubMed

    Alban, Lis; Rugbjerg, Helene; Petersen, Jesper Valentin; Nielsen, Liza Rosenbaum

    2016-06-01

    In Denmark, a monitoring program for residues of antimicrobials in pork is in place involving annual testing of around 20,000 samples from finishing pigs corresponding to 0.1% of the animals slaughtered. Annually, zero to two samples are found above the maximum residue limit. Both authorities and industry have expressed interest in adjusting the monitoring to a risk-based system. The objective of this study was to assess the opportunities and consequences of the monitoring considering: 1) replacing the current bioassay with high-performance liquid chromatography-mass spectrometry (HPLC LC-MS/MS), 2) replacing kidney with muscles as sample matrix, and 3) using indicators to identify high-risk (HR) herds and increase sampling intensity in these herds, lowering sampling in the low-risk (LR) herds, while aiming at continued detection of similar numbers of test-positives at the lowest possible costs. A state-of-the-art stochastic scenario tree modelling approach including economic evaluation of different model outcomes was used. A total of six scenarios were run for penicillin and tetracycline, respectively. Relevant information was obtained through the literature, statistical analysis of existing data as well as consultations with laboratory and slaughterhouse experts. Abattoir recordings of chronic pleuritis were used as an indicator for finishing pig herds (HR=within-herd prevalence>40%). Such risk-based monitoring would have to use muscles and not kidneys, because of logistic challenges in identifying and storing of plucks until testing. However, the bioassay cannot be used on muscle tissue due to low sensitivity for tetracyclines. Different plausible combinations of sample sizes were also modelled. The HPLC LC-MS/MS method detected the same number of cases compared to the bioassay when kidney was used as matrix. HPLC LC-MS/MS has a higher sensitivity when used on muscle but it is almost twice as costly as the bioassay. Risk-based sampling resulted in detection of

  15. Boundary diffraction wave integrals for diffraction modeling of external occulters.

    PubMed

    Cady, Eric

    2012-07-01

    An occulter is a large diffracting screen which may be flown in conjunction with a telescope to image extrasolar planets. The edge is shaped to minimize the diffracted light in a region beyond the occulter, and a telescope may be placed in this dark shadow to view an extrasolar system with the starlight removed. Errors in position, orientation, and shape of the occulter will diffract additional light into this region, and a challenge of modeling an occulter system is to accurately and quickly model these effects. We present a fast method for the calculation of electric fields following an occulter, based on the concept of the boundary diffraction wave: the 2D structure of the occulter is reduced to a 1D edge integral which directly incorporates the occulter shape, and which can be easily adjusted to include changes in occulter position and shape, as well as the effects of sources-such as exoplanets-which arrive off-axis to the occulter. The structure of a typical implementation of the algorithm is included. PMID:22772218

  16. Investigation on Deformation Behavior of Nickel Aluminum Bronze by Neutron Diffraction and Transmission Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoyan; Wang, Hong; Lv, Yuting; Lu, Weijie; Sun, Guangai

    2016-05-01

    The deformation behavior, deformation microstructures, and generated inter-phase stresses of nickel aluminum bronze were investigated by in situ neutron diffraction instrument and transmission electron microscopy in this paper. Lattice strains calculated by both peak shifting and broadening by Gaussian fitting of α and κ phase neutron diffraction peak profiles at both holding stress conditions and unloaded stress conditions were compared. Twining and stacking faults in α matrix were observed after deformed by different tensile stresses. Compressive internal/residual stress in α matrix and tensile internal stress in κ phase in elasto-plastic region were calculated based on neutron diffraction analysis. The piled-up dislocations around hard κ phases increase with increasing the deformation degree, which raise the stress concentration near α/ κ interface and increase the internal stresses.

  17. Multilayer dielectric diffraction gratings

    DOEpatents

    Perry, Michael D.; Britten, Jerald A.; Nguyen, Hoang T.; Boyd, Robert; Shore, Bruce W.

    1999-01-01

    The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described.

  18. Multilayer dielectric diffraction gratings

    DOEpatents

    Perry, M.D.; Britten, J.A.; Nguyen, H.T.; Boyd, R.; Shore, B.W.

    1999-05-25

    The design and fabrication of dielectric grating structures with high diffraction efficiency used in reflection or transmission is described. By forming a multilayer structure of alternating index dielectric materials and placing a grating structure on top of the multilayer, a diffraction grating of adjustable efficiency, and variable optical bandwidth can be obtained. Diffraction efficiency into the first order in reflection varying between 1 and 98 percent has been achieved by controlling the design of the multilayer and the depth, shape, and material comprising the grooves of the grating structure. Methods for fabricating these gratings without the use of ion etching techniques are described. 7 figs.

  19. Quantitative study of solid-state acid-base reactions between polymorphs of flufenamic acid and magnesium oxide using X-ray powder diffraction.

    PubMed

    Chen, Xiaoming; Stowell, Joseph G; Morris, Kenneth R; Byrn, Stephen R

    2010-03-11

    The purpose of this study is to investigate solid-state acid-base reactions between polymorphs of flufenamic acid (FFA) and magnesium oxide (MgO) using X-ray powder diffraction (XRPD). Polymorphs of FFA were blended with MgO and stored under conditions of 96.5% RH and 89% RH at 40 degrees C. The disappearance of FFA and production of magnesium flufenamate were monitored by XRPD. It was observed that the reactions between FFA and MgO proceeded following the Jander equation. Form I of FFA is more reactive with MgO than Form III. Differential accessibility of reactive groups is hypothesized as one of the reasons that Form I is more reactive than Form III. It was noted that the reaction between FFA and MgO could be mitigated by adding another acidic excipient such as polyacrylic acid to prevent the acid-base reaction with FFA. The effectiveness of polyacrylic acid was impacted by the mixing order of the tertiary mixture. Mixing polyacrylic acid and MgO first provided the most significant protection. In conclusion, solid-state acid-base reactions could be investigated using XRPD. Different forms may have distinct reactivity. Acid-base reactions in the solid state could be mitigated through the addition of another "shielding" excipient.

  20. Computation of Fresnel holograms and diffraction-specific coherent panoramagrams for full-color holographic displays based on anisotropic leaky-mode modulators

    NASA Astrophysics Data System (ADS)

    Jolly, Sundeep; Dreshaj, Ermal; Bove, V. M.

    2015-03-01

    We have previously introduced a computational architecture suitable for driving full-color holographic display systems based around anisotropic leaky-mode modulators; this architecture appropriately handles single-sideband modulation and frequency-division multiplexing of spectral bands that correspond to the independent red, green, and blue color channels in the display output. In this paper, we describe an implementation for driving the MIT Mark IV holographic display system with such a computational approach, in cases of both pre-computed Fresnel CGHs and real-time, GPU-based diffraction specific coherent panoramagrams. Real-time holographic images of nearly VGA-resolution (468 lines) are generated via three dual-head NVIDIA GPUs via a CUDA-based implementation that encompasses the requisite orthographic view generation from 3-D data sources, parallel vector-based fringe computation per hogel and per color, single-sideband modulation, and frequency-division multiplexing. We present the first results of this scheme in driving the Mark IV display system and review the resulting holographic video output and performance metrics.

  1. [Study of fast acquisition technique for heavy ion CT system based on the measurement of residual range distribution].

    PubMed

    Mogaki, Tatsuya; Abe, Shinji; Sato, Hitoshi; Muraishi, Hiroshi; Hara, Hidetake; Hara, Satoshi; Miyake, Shoko; Himukai, Takeshi; Kanai, Tatsuaki

    2012-01-01

    We proposed a new technique for the fast acquisition heavy ion CT (HICT) system based on the measurement of residual range distribution using an intensifying screen and charge coupled device camera. The previously used fast acquisition HICT system had poor electron density resolution. In the new technique, the range shifter thickness is varied over the required dynamic range in the spill of the heavy ion beam at each projection angle and the residual range distribution is determined by a series of acquisition data. We examined the image quality using the contrast noise ratio and the noise power spectrum, and estimated the electron density resolution, using a low-contrast phantom for measurement of electron density resolution. The image quality of the new technique was superior to that of the previous fast acquisition HICT system. Furthermore, the relative electron density resolution was 0.011, which represented an improvement of about 12-fold. Therefore we showed that the new technique was potentially useful in clinical use of HICT, including treatment and quality assurance of heavy ion therapy. PMID:24592673

  2. Exploring the Use of Non-Image-Based Ultrasound to Detect the Position of the Residual Femur within a Stump

    PubMed Central

    Chong, Sook-Yee; Röhrle, Oliver

    2016-01-01

    A satisfactorily fitted socket interacts dynamically with the stump in order to support body weight, transmit load effectively, enhance dynamic stability, and enable the control and stabilization of the residual limb. The internal dynamics occurring within a socket is important in determining optimal fit. Many measurement and imaging techniques, such as X-rays, have been utilized to investigate the movement of the residual femur within the stump during gait. However, due to associated health risks and costs, none of the current techniques have been extended to clinical prosthetics. The use of B-mode ultrasound has been suggested as a safe and cheap alternative, and has been utilized in previous studies to monitor the motion of the femur. However, the need to create a duplicate socket and time-consuming analysis of the images were obstacles to the system being applied clinically. This study aims to gauge the effectiveness of a non-image based ultrasound system. Here, we determined errors expected from the measurements. Accuracy errors of 2.9 mm to 8.4 mm and reproducibility measurements within a standard deviation of 3.9 mm are reported. We also estimated errors up to 14.4 mm in in-vivo measurements. We think there is potential in developing this technique, and we hope to reduce some technical difficulties such that it can, one day, be easily incorporated into prosthetic fitting. PMID:27764120

  3. Analysis of Residual Performance of UD-CMC in Oxidation Atmosphere Based on a Notch-like Oxidation Model

    NASA Astrophysics Data System (ADS)

    Sun, Zhigang; Shao, Hongyan; Chen, Xihui; Song, Yingdong

    2016-06-01

    Experimental observation indicates unidirectional ceramic matrix composites (UD-CMC) will react with oxygen under high-temperature atmosphere inhomogeneous. As a result of the oxidation on fiber surface, fiber shows a notch-like morphology. Stress concentration near by the fiber notch causes a decline of the mechanic performance of UD-CMC. In this paper, the change rule of fiber notch depth is fitted by circular function. Based on this formula the residual strength and modulus of UD-CMC under 400-900 °C atmosphere are derived. The mechanical performance of unidirectional C/SiC composite is simulated by finite element method. The stress distribution of fiber, matrix and interface are obtained. The residual properties of unidirectional C/SiC composite are predicted by theoretical method and finite element method. And the predicting results are compared with the experiment data. The predicting results show a good accordance with experiment data, which means the notch-like oxidation model can analyze the mechanic performance of UD-CMC efficiently.

  4. Technique development for characterization of metalloorganics in acid-base-neutral fractions of heavy petroleum residues: Topical report

    SciTech Connect

    Pearson, C.D.; Green, J.B.

    1988-01-01

    A novel approach for the characterization of metallorganic compounds in heavy petroleum residues has been developed. Wilmington 1000/sup 0/ F+ and Mayan 925/sup 0/ F+ residues and hydrotreated products were separated into acid-base-neutral (ABN) fractions by a unique nonaqueous ion-exchange technique developed at NIPER. The metal complexes in the feeds, hydrotreated products and ABN fractions were then characterized by determining the total vanadium and nickel and by measuring the vanadium and nickel porphyrin content of each fraction. Molecular weight distribution profiles of the vanadium and nickel compounds in the feed, 400/sup 0/C hydrotreated product and corresponding ABN fractions were obtained by size exclusion chromatography/inductively coupled plasma. The majority of the metal appeared to be in non-porphyrinic form. The vanadium and nickel complexes were distributed into all of the ABN fractions. In the feed and the whole hydrotreated products the porphyrin levels decreased as hydrotreating temperatures increased. In contrast to previously reported work, porphyrins do not always decrease when hydrotreated. The amount of porphyrins in certain ABN fractions increased after hydrotreating at moderate temperatures. The Mayan V and Ni complexes were more resistant to hydrotreating than the Wilmington metal complexes; in particular, the high molecular weight Mayan metal complexes were more resistant to hydrotreating than the high molecular weight Wilmington metal complexes. 15 refs., 11 figs., 10 tabs.

  5. Adaptive scene-based correction algorithm for removal of residual fixed pattern noise in microgrid image data

    NASA Astrophysics Data System (ADS)

    Ratliff, Bradley M.; LeMaster, Daniel A.

    2012-06-01

    Pixel-to-pixel response nonuniformity is a common problem that affects nearly all focal plane array sensors. This results in a frame-to-frame fixed pattern noise (FPN) that causes an overall degradation in collected data. FPN is often compensated for through the use of blackbody calibration procedures; however, FPN is a particularly challenging problem because the detector responsivities drift relative to one another in time, requiring that the sensor be recalibrated periodically. The calibration process is obstructive to sensor operation and is therefore only performed at discrete intervals in time. Thus, any drift that occurs between calibrations (along with error in the calibration sources themselves) causes varying levels of residual calibration error to be present in the data at all times. Polarimetric microgrid sensors are particularly sensitive to FPN due to the spatial differencing involved in estimating the Stokes vector images. While many techniques exist in the literature to estimate FPN for conventional video sensors, few have been proposed to address the problem in microgrid imaging sensors. Here we present a scene-based nonuniformity correction technique for microgrid sensors that is able to reduce residual fixed pattern noise while preserving radiometry under a wide range of conditions. The algorithm requires a low number of temporal data samples to estimate the spatial nonuniformity and is computationally efficient. We demonstrate the algorithm's performance using real data from the AFRL PIRATE and University of Arizona LWIR microgrid sensors.

  6. Multiple-trait genome-wide association study based on principal component analysis for residual covariance matrix

    PubMed Central

    Gao, H; Zhang, T; Wu, Y; Wu, Y; Jiang, L; Zhan, J; Li, J; Yang, R

    2014-01-01

    Given the drawbacks of implementing multivariate analysis for mapping multiple traits in genome-wide association study (GWAS), principal component analysis (PCA) has been widely used to generate independent ‘super traits' from the original multivariate phenotypic traits for the univariate analysis. However, parameter estimates in this framework may not be the same as those from the joint analysis of all traits, leading to spurious linkage results. In this paper, we propose to perform the PCA for residual covariance matrix instead of the phenotypical covariance matrix, based on which multiple traits are transformed to a group of pseudo principal components. The PCA for residual covariance matrix allows analyzing each pseudo principal component separately. In addition, all parameter estimates are equivalent to those obtained from the joint multivariate analysis under a linear transformation. However, a fast least absolute shrinkage and selection operator (LASSO) for estimating the sparse oversaturated genetic model greatly reduces the computational costs of this procedure. Extensive simulations show statistical and computational efficiencies of the proposed method. We illustrate this method in a GWAS for 20 slaughtering traits and meat quality traits in beef cattle. PMID:24984606

  7. Analysis of Residual Performance of UD-CMC in Oxidation Atmosphere Based on a Notch-like Oxidation Model

    NASA Astrophysics Data System (ADS)

    Sun, Zhigang; Shao, Hongyan; Chen, Xihui; Song, Yingdong

    2016-10-01

    Experimental observation indicates unidirectional ceramic matrix composites (UD-CMC) will react with oxygen under high-temperature atmosphere inhomogeneous. As a result of the oxidation on fiber surface, fiber shows a notch-like morphology. Stress concentration near by the fiber notch causes a decline of the mechanic performance of UD-CMC. In this paper, the change rule of fiber notch depth is fitted by circular function. Based on this formula the residual strength and modulus of UD-CMC under 400-900 °C atmosphere are derived. The mechanical performance of unidirectional C/SiC composite is simulated by finite element method. The stress distribution of fiber, matrix and interface are obtained. The residual properties of unidirectional C/SiC composite are predicted by theoretical method and finite element method. And the predicting results are compared with the experiment data. The predicting results show a good accordance with experiment data, which means the notch-like oxidation model can analyze the mechanic performance of UD-CMC efficiently.

  8. Status of the Neutron Imaging and Diffraction Instrument IMAT

    NASA Astrophysics Data System (ADS)

    Kockelmann, Winfried; Burca, Genoveva; Kelleher, Joe F.; Kabra, Saurabh; Zhang, Shu-Yan; Rhodes, Nigel J.; Schooneveld, Erik M.; Sykora, Jeff; Pooley, Daniel E.; Nightingale, Jim B.; Aliotta, Francesco; Ponterio, Rosa C.; Salvato, Gabriele; Tresoldi, Dario; Vasi, Cirino; McPhate, Jason B.; Tremsin, Anton S.

    A cold neutron imaging and diffraction instrument, IMAT, is currently being constructed at the ISIS second target station. IMAT will capitalize on time-of-flight transmission and diffraction techniques available at a pulsed neutron source. Analytical techniques will include neutron radiography, neutron tomography, energy-selective neutron imaging, and spatially resolved diffraction scans for residual strain and texture determination. Commissioning of the instrument will start in 2015, with time-resolving imaging detectors and two diffraction detector prototype modules. IMAT will be operated as a user facility for material science applications and will be open for developments of time-of-flight imaging methods.

  9. Characterization of flue gas cleaning residues from European solid waste incinerators: assessment of various Ca-based sorbent processes.

    PubMed

    Bodénan, F; Deniard, Ph

    2003-05-01

    For the first time, a set of samples of European flue gas cleaning residues, mainly from the incineration of municipal solid waste (MSW), has undergone a mineralogical study. The residues are the result of the neutralization of acid flue gases by lime, the predominant method adopted in Europe, using dry and semi-dry washing processes. The study protocol combines physico-chemical analytical techniques (XRD, FTIR, DSC/TGA) and global chemical analysis enabling identification of the chemical composition of the main constituents, particularly chlorinated Ca-based phases, as well as establishment of modal distributions of the represented phases, both crystalline and amorphous. The samples are slightly hydrated and values vary for trapped Cl, S and even CO(2). The main crystalline phases are NaCl, KCl, CaSO(4), CaCO(3), Ca(OH)(2) and calcium hydroxychloride CaOHCl. CaOHCl is the main chlorine phase, regardless of the treatment process, filtration mode, and specific surface of the Ca-based sorbent. This phase develops during neutralization of HCl by excess lime present according to the reaction Ca(OH)(2)+HCl-->CaOHCl+H(2)O, to the detriment of a complete yield involving the two lime OH groups with formation of CaCl(2).2H(2)O. In addition, it seems that gas temperatures above 150 degrees C increase competition between lime-based neutralization of HCl, SO(2) acid flue gases and CO(2) trapping, thus reducing washing efficiency. PMID:12597999

  10. Time-resolved titrations of the Schiff base and of the Asp85 residue in artificial bacteriorhodopsins.

    PubMed

    Druckmann, S; Ottolenghi, M; Rousso, I; Friedman, N; Sheves, M

    1995-09-19

    Deprotonation/protonation processes involving the retinal Schiff base and the Asp85 residue play dominant roles in the light-induced proton pump of bacteriorhodopsin (bR). Although the pKa values of these two moieties in unphotolyzed bR are well established, the kinetics of the respective titrations in the native pigment are difficult to interpret, primarily due to the extreme (nonphysiological) pKa values of the two moieties (12.2 +/- 0.2 and 2.7, in 0.1 M NaCl, for the Schiff base and for Asp85, respectively). These difficulties are circumvented by applying stopped-flow techniques, time resolving the titrations of several artificial bRs in which the pKa values of the above two residues are substantially modified: 13-CF3 bR, pKa (Schiff base) = 8.2 +/- 0.2; 13-demethyl-11,14-epoxy bR, pKa (Schiff base) = 8.2 +/- 0.1 (in 0.1 M NaCl); aromatic bR, pKa (Asp85) = 5.2 +/- 0.1 (in water). The R82Q bR mutant, pKa (Asp85) congruent to 7.2 was also employed. A major objective was to verify whether the basic relationships of homogeneous kinetics obeyed by elementary acid/base systems in solution (primarily, the possibility to express the equilibrium constant as the ratio of the forward and back rate constants) are also obeyed by the Schiff base and Asp85 moieties. We found that this is the case for the Schiff base in the pH range between 7 and 9 but not at lower pH. These observations led to the conclusion that the Schiff base is titrable from the outside medium via a proton channel, which becomes saturated, and thus rate determining, below pH approximately equal to 7.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Fraunhofer Diffraction and Polarization.

    ERIC Educational Resources Information Center

    Fortin, E.

    1979-01-01

    Describes an experiment for the intermediate undergraduate optics laboratory designed to illustrate simultaneously some aspects of the phenomena of diffraction; interference, coherence, apodization, the Fresnel-Arago law; as well as of the interrelations between these concepts. (HM)

  12. Fresnel Coherent Diffractive Imaging

    NASA Astrophysics Data System (ADS)

    Williams, G. J.; Quiney, H. M.; Dhal, B. B.; Tran, C. Q.; Nugent, K. A.; Peele, A. G.; Paterson, D.; de Jonge, M. D.

    2006-07-01

    We present an x-ray coherent diffractive imaging experiment utilizing a nonplanar incident wave and demonstrate success by reconstructing a nonperiodic gold sample at 24 nm resolution. Favorable effects of the curved beam illumination are identified.

  13. Multigap Diffraction at LHC

    SciTech Connect

    Goulianos, Konstantin

    2005-10-06

    The large rapidity interval available at the Large Hadron Collider (LHC) offers an arena in which the QCD aspects of diffraction may be explored in an environment free of gap survival complications using events with multiple rapidity gaps.

  14. Reflective diffraction grating

    DOEpatents

    Lamartine, Bruce C.

    2003-06-24

    Reflective diffraction grating. A focused ion beam (FIB) micromilling apparatus is used to store color images in a durable medium by milling away portions of the surface of the medium to produce a reflective diffraction grating with blazed pits. The images are retrieved by exposing the surface of the grating to polychromatic light from a particular incident bearing and observing the light reflected by the surface from specified reception bearing.

  15. Chemometric classification of gunshot residues based on energy dispersive X-ray microanalysis and inductively coupled plasma analysis with mass-spectrometric detection

    NASA Astrophysics Data System (ADS)

    Steffen, S.; Otto, M.; Niewoehner, L.; Barth, M.; Bro¿żek-Mucha, Z.; Biegstraaten, J.; Horváth, R.

    2007-09-01

    A gunshot residue sample that was collected from an object or a suspected person is automatically searched for gunshot residue relevant particles. Particle data (such as size, morphology, position on the sample for manual relocation, etc.) as well as the corresponding X-ray spectra and images are stored. According to these data, particles are classified by the analysis-software into different groups: 'gunshot residue characteristic', 'consistent with gunshot residue' and environmental particles, respectively. Potential gunshot residue particles are manually checked and - if necessary - confirmed by the operating forensic scientist. As there are continuing developments on the ammunition market worldwide, it becomes more and more difficult to assign a detected particle to a particular ammunition brand. As well, the differentiation towards environmental particles similar to gunshot residue is getting more complex. To keep external conditions unchanged, gunshot residue particles were collected using a specially designed shooting device for the test shots revealing defined shooting distances between the weapon's muzzle and the target. The data obtained as X-ray spectra of a number of particles (3000 per ammunition brand) were reduced by Fast Fourier Transformation and subjected to a chemometric evaluation by means of regularized discriminant analysis. In addition to the scanning electron microscopy in combination with energy dispersive X-ray microanalysis results, isotope ratio measurements based on inductively coupled plasma analysis with mass-spectrometric detection were carried out to provide a supplementary feature for an even lower risk of misclassification.

  16. DR_bind: a web server for predicting DNA-binding residues from the protein structure based on electrostatics, evolution and geometry.

    PubMed

    Chen, Yao Chi; Wright, Jon D; Lim, Carmay

    2012-07-01

    DR_bind is a web server that automatically predicts DNA-binding residues, given the respective protein structure based on (i) electrostatics, (ii) evolution and (iii) geometry. In contrast to machine-learning methods, DR_bind does not require a training data set or any parameters. It predicts DNA-binding residues by detecting a cluster of conserved, solvent-accessible residues that are electrostatically stabilized upon mutation to Asp(-)/Glu(-). The server requires as input the DNA-binding protein structure in PDB format and outputs a downloadable text file of the predicted DNA-binding residues, a 3D visualization of the predicted residues highlighted in the given protein structure, and a downloadable PyMol script for visualization of the results. Calibration on 83 and 55 non-redundant DNA-bound and DNA-free protein structures yielded a DNA-binding residue prediction accuracy/precision of 90/47% and 88/42%, respectively. Since DR_bind does not require any training using protein-DNA complex structures, it may predict DNA-binding residues in novel structures of DNA-binding proteins resulting from structural genomics projects with no conservation data. The DR_bind server is freely available with no login requirement at http://dnasite.limlab.ibms.sinica.edu.tw.

  17. Novel strategy for the revalorization of olive (Olea europaea) residues based on the extraction of bioactive peptides.

    PubMed

    Esteve, C; Marina, M L; García, M C

    2015-01-15

    This work proposes a new strategy for the revalorization of residual materials from table-olive and olive oil production based on the extraction of bioactive peptides. Enzymatic hydrolysates of olive seed protein isolate were prepared by treatment with five different proteases: Alcalase, Thermolysin, Neutrase, Flavourzyme and PTN. Although all hydrolysates presented antioxidant properties, Alcalase was the enzyme that yielded the hydrolysate with the highest antioxidant capacity. All hydrolysates showed antihypertensive capacity, obtaining IC50 values from 29 to 350 μg/ml. Thermolysin was the enzyme which yielded the hydrolysate with the highest ACE-inhibitory capacity. Hydrolysates were fractionated by ultrafiltration showing a high concentration of short chain peptides, which exhibited significantly higher antioxidant and antihypertensive capacities than fractions with higher molecular weights. Peptides in most active fractions were identified by LC-MS/MS, observing homologies with other recognized antioxidant and antihypertensive peptides. Finally, their antioxidant and antihypertensive capacities were evaluated after in vitro gastrointestinal digestion.

  18. Allergic effects of the residual monomer used in denture base acrylic resins

    PubMed Central

    Rashid, Haroon; Sheikh, Zeeshan; Vohra, Fahim

    2015-01-01

    Denture base resins are extensively used in dentistry for a variety of purposes. These materials can be classified as chemical, heat, light, and microwave polymerization materials depending upon the factor which starts the polymerization reaction. Their applications include use during denture base construction, relining existing dentures, and for fabrication of orthodontic removable appliances. There have been increased concerns regarding the safe clinical application of these materials as their biodegradation in the oral environment leads to harmful effects. Along with local side effects, the materials have certain occupational hazards, and numerous studies can be found in the literature mentioning those. The purpose of this article is to outline the cytotoxic consequences of denture base acrylic resins and clinical recommendations for their use. PMID:26929705

  19. Allergic effects of the residual monomer used in denture base acrylic resins.

    PubMed

    Rashid, Haroon; Sheikh, Zeeshan; Vohra, Fahim

    2015-01-01

    Denture base resins are extensively used in dentistry for a variety of purposes. These materials can be classified as chemical, heat, light, and microwave polymerization materials depending upon the factor which starts the polymerization reaction. Their applications include use during denture base construction, relining existing dentures, and for fabrication of orthodontic removable appliances. There have been increased concerns regarding the safe clinical application of these materials as their biodegradation in the oral environment leads to harmful effects. Along with local side effects, the materials have certain occupational hazards, and numerous studies can be found in the literature mentioning those. The purpose of this article is to outline the cytotoxic consequences of denture base acrylic resins and clinical recommendations for their use.

  20. Prediction of hot spot residues at protein-protein interfaces by combining machine learning and energy-based methods

    PubMed Central

    Lise, Stefano; Archambeau, Cedric; Pontil, Massimiliano; Jones, David T

    2009-01-01

    Background Alanine scanning mutagenesis is a powerful experimental methodology for investigating the structural and energetic characteristics of protein complexes. Individual amino-acids are systematically mutated to alanine and changes in free energy of binding (ΔΔG) measured. Several experiments have shown that protein-protein interactions are critically dependent on just a few residues ("hot spots") at the interface. Hot spots make a dominant contribution to the free energy of binding and if mutated they can disrupt the interaction. As mutagenesis studies require significant experimental efforts, there is a need for accurate and reliable computational methods. Such methods would also add to our understanding of the determinants of affinity and specificity in protein-protein recognition. Results We present a novel computational strategy to identify hot spot residues, given the structure of a complex. We consider the basic energetic terms that contribute to hot spot interactions, i.e. van der Waals potentials, solvation energy, hydrogen bonds and Coulomb electrostatics. We treat them as input features and use machine learning algorithms such as Support Vector Machines and Gaussian Processes to optimally combine and integrate them, based on a set of training examples of alanine mutations. We show that our approach is effective in predicting hot spots and it compares favourably to other available methods. In particular we find the best performances using Transductive Support Vector Machines, a semi-supervised learning scheme. When hot spots are defined as those residues for which ΔΔG ≥ 2 kcal/mol, our method achieves a precision and a recall respectively of 56% and 65%. Conclusion We have developed an hybrid scheme in which energy terms are used as input features of machine learning models. This strategy combines the strengths of machine learning and energy-based methods. Although so far these two types of approaches have mainly been applied separately to

  1. COMSAT: Residue contact prediction of transmembrane proteins based on support vector machines and mixed integer linear programming.

    PubMed

    Zhang, Huiling; Huang, Qingsheng; Bei, Zhendong; Wei, Yanjie; Floudas, Christodoulos A

    2016-03-01

    In this article, we present COMSAT, a hybrid framework for residue contact prediction of transmembrane (TM) proteins, integrating a support vector machine (SVM) method and a mixed integer linear programming (MILP) method. COMSAT consists of two modules: COMSAT_SVM which is trained mainly on position-specific scoring matrix features, and COMSAT_MILP which is an ab initio method based on optimization models. Contacts predicted by the SVM model are ranked by SVM confidence scores, and a threshold is trained to improve the reliability of the predicted contacts. For TM proteins with no contacts above the threshold, COMSAT_MILP is used. The proposed hybrid contact prediction scheme was tested on two independent TM protein sets based on the contact definition of 14 Å between Cα-Cα atoms. First, using a rigorous leave-one-protein-out cross validation on the training set of 90 TM proteins, an accuracy of 66.8%, a coverage of 12.3%, a specificity of 99.3% and a Matthews' correlation coefficient (MCC) of 0.184 were obtained for residue pairs that are at least six amino acids apart. Second, when tested on a test set of 87 TM proteins, the proposed method showed a prediction accuracy of 64.5%, a coverage of 5.3%, a specificity of 99.4% and a MCC of 0.106. COMSAT shows satisfactory results when compared with 12 other state-of-the-art predictors, and is more robust in terms of prediction accuracy as the length and complexity of TM protein increase. COMSAT is freely accessible at http://hpcc.siat.ac.cn/COMSAT/. PMID:26756402

  2. Production of 15N-Labelled Liquid Organic Fertilisers Based on Manure and Crop Residue for Use in Fertigation Studies.

    PubMed

    Martínez-Alcántara, Belén; Martínez-Cuenca, Mary-Rus; Fernández, Carlos; Legaz, Francisco; Quiñones, Ana

    2016-01-01

    Large quantities of crop residue and animal manure from agricultural and livestock activities are annually produced worldwide. With proper management, these residues are potentially valuable sources of plant nutrients, mainly N. Recycling such subproducts in sustainably-based agricultural systems can minimise the use of mineral fertilisers, and hence reduce the potential risk of surface and groundwater pollution. Therefore, the purpose of this study was to obtain (small scale) two liquid labelled-organic fertilisers, an animal- and a vegetal-based organic (AO and VO, respectively) fertiliser, to be used as organic N sources in subsequent fertigation studies. Forage maize (Zea mays L.) grown under 15N-labelled fertiliser supply was used as raw material for VO fertiliser production, and also as 15N-labelled sheep feed to obtain 15N-labelled manure. The labelled faeces fraction was used as raw material for the AO fertiliser. The VO fertiliser was obtained after an acidic and an enzyme-driven hydrolysis. The AO fertiliser was obtained after acidic hydrolysis. The VO liquid fertiliser presented an N concentration of 330 mg·L-1, 85% of total N was organic, while ammonium and nitrate N accounted for 55% and 45% of the mineral nitrogen fraction, respectively. This fertiliser also exhibited high K, Ca and S concentrations and notable values for the remaining macro- and micronutrients. The AO liquid fertiliser had a similar total N concentration (496 mg·L-1, 82% of total N in an organic form) to that of VO, but its mineral N fraction significantly differed, which came in a predominantly (95%) ammonia form. It also had a high content of N, P, K and other macronutrients, and sufficient Fe, Zn, Mn, Cu and B levels, which suggests its suitability as a potential fertiliser. The percentage of 15N enrichment in both VO and AO liquid fertilisers exceeded 2% 15N atom excess, which enabled their use in subsequent assays run to assess nitrogen uptake efficiency.

  3. COMSAT: Residue contact prediction of transmembrane proteins based on support vector machines and mixed integer linear programming.

    PubMed

    Zhang, Huiling; Huang, Qingsheng; Bei, Zhendong; Wei, Yanjie; Floudas, Christodoulos A

    2016-03-01

    In this article, we present COMSAT, a hybrid framework for residue contact prediction of transmembrane (TM) proteins, integrating a support vector machine (SVM) method and a mixed integer linear programming (MILP) method. COMSAT consists of two modules: COMSAT_SVM which is trained mainly on position-specific scoring matrix features, and COMSAT_MILP which is an ab initio method based on optimization models. Contacts predicted by the SVM model are ranked by SVM confidence scores, and a threshold is trained to improve the reliability of the predicted contacts. For TM proteins with no contacts above the threshold, COMSAT_MILP is used. The proposed hybrid contact prediction scheme was tested on two independent TM protein sets based on the contact definition of 14 Å between Cα-Cα atoms. First, using a rigorous leave-one-protein-out cross validation on the training set of 90 TM proteins, an accuracy of 66.8%, a coverage of 12.3%, a specificity of 99.3% and a Matthews' correlation coefficient (MCC) of 0.184 were obtained for residue pairs that are at least six amino acids apart. Second, when tested on a test set of 87 TM proteins, the proposed method showed a prediction accuracy of 64.5%, a coverage of 5.3%, a specificity of 99.4% and a MCC of 0.106. COMSAT shows satisfactory results when compared with 12 other state-of-the-art predictors, and is more robust in terms of prediction accuracy as the length and complexity of TM protein increase. COMSAT is freely accessible at http://hpcc.siat.ac.cn/COMSAT/.

  4. Residual stress and plastic anisotropy in indented 2024-T351 aluminum disks

    SciTech Connect

    Clausen, Bjorn; Prime, Michael B; Saurabh, Kabra; Brown, Donald W; Pagliaro, Pierluigi; Backlund, Peter; Shaw, Sanjiv; Criss, Everett

    2009-01-01

    Recent studies have proven that generating a well defined residual stress state using the indented disk approach is an excellent way to validate experimental and modeling techniques for measuring and predicting residual stresses. The previous studies dealt with indented stainless steel disks, and included experimental determination of residual stresses using the Contour Method and neutron diffraction measurements. The measured residual stress states showed good agreement between the techniques, and a Finite Element Model predicted residual stress state based upon material properties determined form standard tension and compression/tension tests was also in good agreement with the measurements. In the present work, disks of 2024-T351 Aluminum were investigated. As before, the residual stress profile was measured using neutron diffraction and the Contour Method and Finite Element Modeling was employed to predict the residual stress profile. Analysis and comparison of the three techniques were complicated by the fact that the experimental data shows evidence of plastic anisotropy and strong Bauschinger effect within the indented disks.

  5. Crystallization and preliminary X-ray diffraction analysis of the Bacillus subtilis replication termination protein in complex with the 37-base-pair TerI-binding site

    SciTech Connect

    Vivian, J. P.; Porter, C.; Wilce, J. A.; Wilce, M. C. J.

    2006-11-01

    A preparation of replication terminator protein (RTP) of B. subtilis and a 37-base-pair TerI sequence (comprising two binding sites for RTP) has been purified and crystallized. The replication terminator protein (RTP) of Bacillus subtilis binds to specific DNA sequences that halt the progression of the replisome in a polar manner. These terminator complexes flank a defined region of the chromosome into which they allow replication forks to enter but not exit. Forcing the fusion of replication forks in a specific zone is thought to allow the coordination of post-replicative processes. The functional terminator complex comprises two homodimers each of 29 kDa bound to overlapping binding sites. A preparation of RTP and a 37-base-pair TerI sequence (comprising two binding sites for RTP) has been purified and crystallized. A data set to 3.9 Å resolution with 97.0% completeness and an R{sub sym} of 12% was collected from a single flash-cooled crystal using synchrotron radiation. The diffraction data are consistent with space group P622, with unit-cell parameters a = b = 118.8, c = 142.6 Å.

  6. A method for measuring single-crystal elastic moduli using high-energy X-ray diffraction and a crystal-based finite element model

    SciTech Connect

    Efstathiou, C.; Boyce, D.E.; Park, J.-S.; Lienert, U.; Dawson, P.R.; Miller, M.P.

    2010-11-30

    This paper presents a method - based on high-energy synchrotron X-ray diffraction data and a crystal-based finite element simulation formulation - for understanding grain scale deformation behavior within a polycrystalline aggregate. We illustrate this method by using it to determine the single-crystal elastic moduli of {beta}21s, a body-centered cubic titanium alloy. We employed a polycrystalline sample. Using in situ loading and high-energy X-rays at the Advanced Photon Source beamline 1-ID-C, we measured components of the lattice strain tensor from four individual grains embedded within a polycrystalline specimen. We implemented an optimization routine that minimized the difference between the experiment and simulation lattice strains. Sensitivity coefficients needed in the optimization routine are generated numerically using the finite element model. The elastic moduli that we computed for the {beta}21s are C{sub 11} = 110 GPa, C{sub 12} = 74 GPa and C{sub 44} = 89 GPa. The resulting Zener anisotropic ratio is A = 5.

  7. Multifamily determination of pesticide residues in soya-based nutraceutical products by GC/MS-MS.

    PubMed

    Páleníková, Agneša; Martínez-Domínguez, Gerardo; Arrebola, Francisco Javier; Romero-González, Roberto; Hrouzková, Svetlana; Frenich, Antonia Garrido

    2015-04-15

    An analytical method based on a modified QuEChERS extraction coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS) was evaluated for the determination of 177 pesticides in soya-based nutraceutical products. The QuEChERS method was optimised and different extraction solvents and clean-up approaches were tested, obtaining the most efficient conditions with a mixture of sorbents (PSA, C18, GBC and Zr-Sep(+)). Recoveries were evaluated at 10, 50 and 100 μg/kg and ranged between 70% and 120%. Precision was expressed as relative standard deviation (RSD), and it was evaluated for more than 160 pesticides as intra and inter-day precision, with values always below 20% and 25%, respectively. Limits of detection (LODs) ranged from 0.1 to 10 μg/kg, whereas limits of quantification (LOQs) from 0.5 to 20 μg/kg. The applicability of the method was proved by analysing soya-based nutraceuticals. Two pesticides were found in these samples, malathion and pyriproxyfen, at 11.1 and 1.5 μg/kg respectively.

  8. Web-Based Intervention in Mindfulness Meditation for Reducing Residual Depressive Symptoms and Relapse Prophylaxis: A Qualitative Study

    PubMed Central

    2014-01-01

    Background Mindful Mood Balance (MMB) is a Web-based intervention designed to treat residual depressive symptoms and prevent relapse. MMB was designed to deliver the core concepts of mindfulness-based cognitive therapy (MBCT), a group treatment, which, despite its strong evidence base, faces a number of dissemination challenges. Objective The present study is a qualitative investigation of participants’ experiences with MMB. Methods Qualitative content analysis was conducted via 38 exit interviews with MMB participants. Study inclusion required a current PHQ-9 (Patient Health Questionnaire) score ≤12 and lifetime history ≥1 major depressive episode. Feedback was obtained on specific website components, program content, and administration as well as skills learned. Results Codes were assigned to interview responses and organized into four main themes: MBCT Web content, MBCT Web-based group process, home practice, and evidence of concept comprehension. Within these four areas, participants highlighted the advantages and obstacles of translating and delivering MBCT in a Web-based format. Adding increased support was suggested for troubleshooting session content as well as managing time challenges for completing home mindfulness practice. Participants endorsed developing affect regulation skills and identified several advantages to Web-based delivery including flexibility, reduced cost, and time commitment. Conclusions These findings support the viability of providing MBCT online and are consistent with prior qualitative accounts derived from in-person MBCT groups. While there is certainly room for innovation in the domains of program support and engagement, the high levels of participant satisfaction indicated that MMB can significantly increase access to evidence-based psychological treatments for sub-threshold symptoms of unipolar affective disorder. PMID:24662625

  9. A Benchmark Study on Casting Residual Stress

    SciTech Connect

    Johnson, Eric M.; Watkins, Thomas R; Schmidlin, Joshua E; Dutler, S. A.

    2012-01-01

    Stringent regulatory requirements, such as Tier IV norms, have pushed the cast iron for automotive applications to its limit. The castings need to be designed with closer tolerances by incorporating hitherto unknowns, such as residual stresses arising due to thermal gradients, phase and microstructural changes during solidification phenomenon. Residual stresses were earlier neglected in the casting designs by incorporating large factors of safety. Experimental measurement of residual stress in a casting through neutron or X-ray diffraction, sectioning or hole drilling, magnetic, electric or photoelastic measurements is very difficult and time consuming exercise. A detailed multi-physics model, incorporating thermo-mechanical and phase transformation phenomenon, provides an attractive alternative to assess the residual stresses generated during casting. However, before relying on the simulation methodology, it is important to rigorously validate the prediction capability by comparing it to experimental measurements. In the present work, a benchmark study was undertaken for casting residual stress measurements through neutron diffraction, which was subsequently used to validate the accuracy of simulation prediction. The stress lattice specimen geometry was designed such that subsequent castings would generate adequate residual stresses during solidification and cooling, without any cracks. The residual stresses in the cast specimen were measured using neutron diffraction. Considering the difficulty in accessing the neutron diffraction facility, these measurements can be considered as benchmark for casting simulation validations. Simulations were performed using the identical specimen geometry and casting conditions for predictions of residual stresses. The simulation predictions were found to agree well with the experimentally measured residual stresses. The experimentally validated model can be subsequently used to predict residual stresses in different cast

  10. Multipath analysis diffraction calculations

    NASA Technical Reports Server (NTRS)

    Statham, Richard B.

    1996-01-01

    This report describes extensions of the Kirchhoff diffraction equation to higher edge terms and discusses their suitability to model diffraction multipath effects of a small satellite structure. When receiving signals, at a satellite, from the Global Positioning System (GPS), reflected signals from the satellite structure result in multipath errors in the determination of the satellite position. Multipath error can be caused by diffraction of the reflected signals and a method of calculating this diffraction is required when using a facet model of the satellite. Several aspects of the Kirchhoff equation are discussed and numerical examples, in the near and far fields, are shown. The vector form of the extended Kirchhoff equation, by adding the Larmor-Tedone and Kottler edge terms, is given as a mathematical model in an appendix. The Kirchhoff equation was investigated as being easily implemented and of good accuracy in the basic form, especially in phase determination. The basic Kirchhoff can be extended for higher accuracy if desired. A brief discussion of the method of moments and the geometric theory of diffraction is included, but seems to offer no clear advantage in implementation over the Kirchhoff for facet models.

  11. A Synchrotron-Based Hydroxyl Radical Footprinting Analysis of Amyloid Fibrils and Prefibrillar Intermediates with Residue-Specific Resolution

    PubMed Central

    2015-01-01

    Structural models of the fibrils formed by the 40-residue amyloid-β (Aβ40) peptide in Alzheimer’s disease typically consist of linear polypeptide segments, oriented approximately perpendicular to the long axis of the fibril, and joined together as parallel in-register β-sheets to form filaments. However, various models differ in the number of filaments that run the length of a fibril, and in the topological arrangement of these filaments. In addition to questions about the structure of Aβ40 monomers in fibrils, there are important unanswered questions about their structure in prefibrillar intermediates, which are of interest because they may represent the most neurotoxic form of Aβ40. To assess different models of fibril structure and to gain insight into the structure of prefibrillar intermediates, the relative solvent accessibility of amino acid residue side chains in fibrillar and prefibrillar Aβ40 preparations was characterized in solution by hydroxyl radical footprinting and structural mass spectrometry. A key to the application of this technology was the development of hydroxyl radical reactivity measures for individual side chains of Aβ40. Combined with mass-per-length measurements performed by dark-field electron microscopy, the results of this study are consistent with the core filament structure represented by two- and three-filament solid state nuclear magnetic resonance-based models of the Aβ40 fibril (such as 2LMN, 2LMO, 2LMP, and 2LMQ), with minor refinements, but they are inconsistent with the more recently proposed 2M4J model. The results also demonstrate that individual Aβ40 fibrils exhibit structural heterogeneity or polymorphism, where regions of two-filament structure alternate with regions of three-filament structure. The footprinting approach utilized in this study will be valuable for characterizing various fibrillar and nonfibrillar forms of the Aβ peptide. PMID:25382225

  12. A Synchrotron-Based Hydroxyl Radical Footprinting Analysis of Amyloid Fibrils and Prefibrillar Intermediates with Residue-Specific Resolution

    SciTech Connect

    Klinger, Alexandra L.; Kiselar, Janna; Ilchenko, Serguei; Komatsu, Hiroaki; Chance, Mark R.; Axelsen, Paul H.

    2014-11-09

    The structural models of the fibrils formed by the 40-residue amyloid-β (Aβ40) peptide in Alzheimer’s disease typically consist of linear polypeptide segments, oriented approximately perpendicular to the long axis of the fibril, and joined together as parallel in-register β-sheets to form filaments. However, various models differ in the number of filaments that run the length of a fibril, and in the topological arrangement of these filaments. In addition to questions about the structure of Aβ40 monomers in fibrils, there are important unanswered questions about their structure in prefibrillar intermediates, which are of interest because they may represent the most neurotoxic form of Aβ40. To assess different models of fibril structure and to gain insight into the structure of prefibrillar intermediates, the relative solvent accessibility of amino acid residue side chains in fibrillar and prefibrillar Aβ40 preparations was characterized in solution by hydroxyl radical footprinting and structural mass spectrometry. A key to the application of this technology was the development of hydroxyl radical reactivity measures for individual side chains of Aβ40. When we combined mass-per-length measurements performed by dark-field electron microscopy, we determined that the results of our study were consistent with the core filament structure represented by two- and three-filament solid state nuclear magnetic resonance-based models of the Aβ40 fibril (such as 2LMN, 2LMO, 2LMP, and 2LMQ), with minor refinements, but they are inconsistent with the more recently proposed 2M4J model. Our results also demonstrate that individual Aβ40 fibrils exhibit structural heterogeneity or polymorphism, where regions of two-filament structure alternate with regions of three-filament structure. The footprinting approach utilized in this study will be valuable for characterizing various fibrillar and nonfibrillar forms of the Aβ peptide.

  13. Modification and re-validation of the ethyl acetate-based multi-residue method for pesticides in produce

    PubMed Central

    Rooseboom, Astrid; van Dam, Ruud; Roding, Marleen; Arondeus, Karin; Sunarto, Suryati

    2007-01-01

    The ethyl acetate-based multi-residue method for determination of pesticide residues in produce has been modified for gas chromatographic (GC) analysis by implementation of dispersive solid-phase extraction (using primary–secondary amine and graphitized carbon black) and large-volume (20 μL) injection. The same extract, before clean-up and after a change of solvent, was also analyzed by liquid chromatography with tandem mass spectrometry (LC–MS–MS). All aspects related to sample preparation were re-assessed with regard to ease and speed of the analysis. The principle of the extraction procedure (solvent, salt) was not changed, to avoid the possibility invalidating data acquired over past decades. The modifications were made with techniques currently commonly applied in routine laboratories, GC–MS and LC–MS–MS, in mind. The modified method enables processing (from homogenization until final extracts for both GC and LC) of 30 samples per eight hours per person. Limits of quantification (LOQs) of 0.01 mg kg−1 were achieved with both GC–MS (full-scan acquisition, 10 mg matrix equivalent injected) and LC–MS–MS (2 mg injected) for most of the pesticides. Validation data for 341 pesticides and degradation products are presented. A compilation of analytical quality-control data for pesticides routinely analyzed by GC–MS (135 compounds) and LC–MS–MS (136 compounds) in over 100 different matrices, obtained over a period of 15 months, are also presented and discussed. At the 0.05 mg kg−1 level acceptable recoveries were obtained for 93% (GC–MS) and 92% (LC–MS–MS) of pesticide–matrix combinations. PMID:17563885

  14. Medium for polarization-sensitive diffraction gratings.

    PubMed

    Vretik, L O; Davidenko, N A; Davidenko, I I; Syromyatnikov, V G; Studzinsky, S L; Zagnij, V V

    2014-04-01

    New polymers applicable for optoelectronics are developed and investigated. The ability to form photoinduced anisotropy in the media based on the films of these polymers is demonstrated. The media can be used for recording of polarization-sensitive diffraction gratings.

  15. Inelastic diffraction and equivalence of states

    NASA Astrophysics Data System (ADS)

    Malecki, A.

    1991-09-01

    A new approach to diffraction, based on the concept of equivalent states, is applied to the inclusive inelastic scattering. Differences from the classical description of Good and Walker are pointed out.

  16. Diffraction by nanocrystals II.

    PubMed

    Chen, Joe P J; Millane, Rick P

    2014-08-01

    Nanocrystals with more than one molecule in the unit cell will generally crystallize with incomplete unit cells on the crystal surface. Previous results show that the ensemble-averaged diffraction by such crystals consists of a usual Bragg component and two other Bragg-like components due to the incomplete unit cells. Using an intrinsic flexibility in the definition of the incomplete-unit-cell part of a crystal, the problem is formulated such that the magnitude of the Bragg-like components is minimized, which leads to a simpler and more useful interpretation of the diffraction. Simulations show the nature of the relative magnitudes of the diffraction components in different regions of reciprocal space and the effect of crystal faceting. PMID:25121528

  17. Diffraction Analysis of Solar Coronagraphs

    NASA Astrophysics Data System (ADS)

    Rabin, Douglas M.; gong, qian

    2016-05-01

    The design of a solar coronagraph is predicated on controlling diffracted and scattered light using principles dating back to Bernard Lyot in the 1930’s. The existence of many successful ground- and space-based coronagraphs testifies to our ability to apply these principles in specific cases, but it is difficult to explore a significant range of design parameters because the calculations are tricky and time-consuming. Indeed, scattered light is so design-specific that ad hoc analysis is unavoidable once guidelines from experience are used to create a first-guess system of baffles and low-scatter surfaces. Here we describe a combination of analytic and computational approaches that has the potential to explore coronagraph design space somewhat more systematically with respect to diffracted light.

  18. Stabilization/solidification of a municipal solid waste incineration residue using fly ash-based geopolymers.

    PubMed

    Luna Galiano, Y; Fernández Pereira, C; Vale, J

    2011-01-15

    The stabilization/solidification (S/S) of a municipal solid waste incineration (MSWI) fly ash containing hazardous metals such as Pb, Cd, Cr, Zn or Ba by means of geopolymerization technology is described in this paper. Different reagents such as sodium hydroxide, potassium hydroxide, sodium silicate, potassium silicate, kaolin, metakaolin and ground blast furnace slag have been used. Mixtures of MSWI waste with these kinds of geopolymeric materials and class F coal fly ash used as silica and alumina source have been processed to study the potential of geopolymers as waste immobilizing agents. To this end, the effects of curing conditions and composition have been tested. S/S solids are submitted to compressive strength and leaching tests to assess the results obtained and to evaluate the efficiency of the treatment. Compressive strength values in the range 1-9 MPa were easily obtained at 7 and 28 days. Concentrations of the metals leached from S/S products were strongly pH dependent, showing that the leachate pH was the most important variable for the immobilization of metals. Comparison of fly ash-based geopolymer systems with classical Portland cement stabilization methods has also been accomplished.

  19. Composites based on PET and red mud residues as catalyst for organic removal from water.

    PubMed

    Bento, Natálya I; Santos, Patrícia S C; de Souza, Talita E; Oliveira, Luiz C A; Castro, Cínthia S

    2016-08-15

    In this study, we obtained a composite based on carbon/iron oxide from red mud and PET (poly(ethylene terephthalate)) wastes by mechanical mixture (10, 15 and 20wt.% of PET powder/red mud) followed by a controlled thermal treatment at 400°C under air. XRD analyses revealed that the α-Fe2O3 is the main phase formed from red mud. TPR analyses showed that the iron oxide present in the composites undergoes reduction at lower temperature to form Fe(2+) species present in Fe3O4, indicating that the iron oxide in the composite can exhibit greater reactivity in the catalytic processes compared to the original red mud. In fact, catalytic tests showed that the composites presented higher capacity to remove methylene blue dye (MB), presenting about 90% of removal after 24h of reaction. The MB removal was also monitored by mass spectrometer with ionization via electrospray (ESI-MS), which demonstrated the occurrence of the oxidation process, showing the formation of MB oxidation products. The stability of the composites was confirmed after four reuse cycles. The results seem to indicate that PET carbon deposited over the iron oxide from red mud promotes adsorption of the contaminant allowing its contact with the iron atoms and their consequent reaction.

  20. Revealing the powdering methods of black makeup in Ancient Egypt by fitting microstructure based Fourier coefficients to the whole x-ray diffraction profiles of galena

    NASA Astrophysics Data System (ADS)

    Ungár, T.; Martinetto, P.; Ribárik, G.; Dooryhée, E.; Walter, Ph.; Anne, M.

    2002-02-01

    Galena (PbS) is a major ingredient in ancient Egyptian eye makeup. The microstructure of PbS in Egyptian cosmetic powders is used as a fingerprint and is matched with the microstructures produced artificially in geological galena minerals. The microstructure of PbS is determined by x-ray diffraction peak profile analysis in terms of dislocation density, crystallite size, and size distribution. High-resolution powder diffractograms were measured at the ESRF Grenoble synchrotron source with high resolution and high peak-to-background ratios. The Fourier coefficients of the first nine measured reflections of galena are fitted using physically based Fourier coefficients of strain and size functions. Strain anisotropy is accounted for by the dislocation model of the mean square strain. The x-ray data are supplemented by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) micrographs, and are compared with archæological documents. It enables us to describe the procedures of eye makeup manufacturing in the Middle and New Kingdoms of Egypt some 2000 years before Christ.

  1. Phase-specific high temperature creep behaviour of a pre-rafted Ni-based superalloy studied by X-ray synchrotron diffraction

    NASA Astrophysics Data System (ADS)

    Dirand, L.; Jacques, A.; Chateau-Cornu, J. Ph.; Schenk, T.; Ferry, O.; Bastie, P.

    2013-04-01

    The phase-specific high temperature creep behaviours of the γ and γ‧ phases of a rafted Ni-based single crystal superalloy were investigated by a combination of in situ creep experiments and diffraction of high-energy X-ray synchrotron radiation. In situ experiments were performed at constant temperatures in a 930-1125 °C temperature range and under variable applied stress in order to study the material's response (plastic strain, load transfer) to stress jumps. Using three crystal diffractometry in transmission (Laue) geometry, it was possible to measure the average lattice parameters of both the matrix and the rafts in the [1 0 0] direction at intervals shorter than 300 s. The absolute precision on the measurement of the constrained transverse mismatch (in the rafts' plane) is better than 10-5. Plastic strain occurs within the γ corridors as soon as the Von Mises stress exceeds the Orowan stress. The plasticity of the γ‧ rafts apparently depends on the transverse stress (i.e. perpendicular to the tensile axis) exceeding a threshold value of 60 MPa.

  2. Broadband and High Sensitive Time-of-Flight Diffraction Ultrasonic Transducers Based on PMNT/Epoxy 1–3 Piezoelectric Composite

    PubMed Central

    Liu, Dongxu; Yue, Qingwen; Deng, Ji; Lin, Di; Li, Xiaobing; Di, Wenning; Wang, Xi’an; Zhao, Xiangyong; Luo, Haosu

    2015-01-01

    5–6 MHz PMNT/epoxy 1–3 composites were prepared by a modified dice-and-fill method. They exhibit excellent properties for ultrasonic transducer applications, such as ultrahigh thickness electromechanical coupling coefficient kt (85.7%), large piezoelectric coefficient d33 (1209 pC/N), and relatively low acoustic impedance Z (1.82 × 107 kg/(m2·s)). Besides, two types of Time-of-Flight Diffraction (TOFD) ultrasonic transducers have been designed, fabricated, and characterized, which have different matching layer schemes with the acoustic impedance of 4.8 and 5.7 × 106 kg/(m2·s), respectively. In the detection on a backwall of 12.7 mm polystyrene, the former exhibits higher detectivity, the relative pulse-echo sensitivity and −6 dB relative bandwidth are −21.93 dB and 102.7%, respectively, while the later exhibits broader bandwidth, the relative pulse-echo sensitivity and −6 dB relative bandwidth are −24.08 dB and 117.3%, respectively. These TOFD ultrasonic transducers based on PMNT/epoxy 1–3 composite exhibit considerably improved performance over the commercial PZT/epoxy 1–3 composite TOFD ultrasonic transducer. PMID:25808776

  3. Innovative market-based policy instruments for waste management: A case study on shredder residues in Belgium.

    PubMed

    Dubois, Maarten; Hoogmartens, Rob; Van Passel, Steven; Van Acker, Karel; Vanderreydt, Ive

    2015-10-01

    In an increasingly complex waste market, market-based policy instruments, such as disposal taxes, can give incentives for sustainable progress while leaving flexibility for innovation. However, implementation of disposal taxes is often criticised by domestic waste handlers that fear to be outcompeted by competitors in other countries. The article discusses three innovative market-based instruments that limit the impact on international competitiveness: Tradable recycling credits, refunded disposal taxes and differentiated disposal taxes. All three instruments have already been implemented for distinct environmental policies in Europe. In order to illustrate how these instruments can be used for waste policy, the literature review is complemented with a case study on shredder residues from metal-containing waste streams in Belgium. The analysis shows that a conventional disposal tax remains the most efficient, simple and transparent instrument. However, if international competition is a significant issue or if political support is weak, refunded and differentiated disposal taxes can have an added value as second-best instruments. Tradable recycling credits are not an appropriate instrument for use in small waste markets with market power. In addition, refunded taxes create similar incentives, but induce lower transactions costs. PMID:26395844

  4. Monitoring of the volcanic plume based on the post-fit phase residual of PPP analysis and SNR data

    NASA Astrophysics Data System (ADS)

    Ohta, Yusaku; Iguchi, Masato

    2016-04-01

    A volcanic explosion is one of the largest energy-release phenomena on earth. For example, vulcanian eruptions usually eject large amounts of rock mass, tephra, and volcanic ash. Ash fall from such events can seriously affect the structural integrity of buildings, in addition to disrupting land and air traffic. Therefore, the monitoring and prediction of ash fall is very important. In this study, using data from a dense GNSS network, we investigated the spatiotemporal development of the volcanic plume ejected by the vulcanian eruption in Sakurajima, southwestern Japan on July 24, 2012. We extracted the post-fit phase residuals (PPR) of ionosphere-free linear combinations for each satellite based on the precise point positioning approach. Temporal and spatial PPR anomalies clearly detected the movement of the volcanic plume. The maximum height of the crossing points of anomalous PPR paths was determined to be approximately 4000 m. We then compared the PPR with the signal-to-noise ratio (SNR) anomalies. Only the path passing just above the crater showed significant change in the SNR value, suggesting that the volcanic ash and the water vapor within the volcanic plume became separated after reaching a high altitude because of ash fall during the plume's lateral movement. In the presentation, we will introduce the eruption in Shin-dake (Kuchinoerabu island, southwestern Japan) on May 29, 2015 based on the SNR data.

  5. Innovative market-based policy instruments for waste management: A case study on shredder residues in Belgium.

    PubMed

    Dubois, Maarten; Hoogmartens, Rob; Van Passel, Steven; Van Acker, Karel; Vanderreydt, Ive

    2015-10-01

    In an increasingly complex waste market, market-based policy instruments, such as disposal taxes, can give incentives for sustainable progress while leaving flexibility for innovation. However, implementation of disposal taxes is often criticised by domestic waste handlers that fear to be outcompeted by competitors in other countries. The article discusses three innovative market-based instruments that limit the impact on international competitiveness: Tradable recycling credits, refunded disposal taxes and differentiated disposal taxes. All three instruments have already been implemented for distinct environmental policies in Europe. In order to illustrate how these instruments can be used for waste policy, the literature review is complemented with a case study on shredder residues from metal-containing waste streams in Belgium. The analysis shows that a conventional disposal tax remains the most efficient, simple and transparent instrument. However, if international competition is a significant issue or if political support is weak, refunded and differentiated disposal taxes can have an added value as second-best instruments. Tradable recycling credits are not an appropriate instrument for use in small waste markets with market power. In addition, refunded taxes create similar incentives, but induce lower transactions costs.

  6. Effect of graded interlayer on the mode I edge delamination by residual stresses in multilayer coating-based systems

    NASA Astrophysics Data System (ADS)

    Zhang, X. C.; Xu, B. S.; Wang, H. D.; Wu, Y. X.

    2008-01-01

    The mode I edge delamination could be initiated due to the presence of the interfacial peeling stresses near the edges of the multilayered systems due to the material mismatches between the adjacent layers. However, the exact peeling stress distributions could not be obtained by using the existing analytical and numerical models. It was proposed recently that the peeling moment resulting from the localized peeling stresses could be used to characterize mode I edge delamination. In this paper, the effect of the graded interlayer on the mode I edge delamination by thermal residual stresses in multilayer coating-based systems was investigated. Following the previous analysis approaches, the exact closed-form solutions for the peeling moments at individual interfaces and the curvatures for bilayer system, typical thermal barrier coating (TBC) system and TBC-based system with a graded interlayer inserted between the metallic layer and the ceramic layer were, respectively, derived. Case studies showed that the edge delamination by thermal stress could be impeded by properly selecting the coating materials and individual layer thicknesses. These studies may provide some important insights for developing fail-safe designing methodologies for multilayered systems.

  7. Digital diffractive optics: Have diffractive optics entered mainstream industry yet?

    NASA Astrophysics Data System (ADS)

    Kress, Bernard; Hejmadi, Vic

    2010-05-01

    When a new technology is integrated into industry commodity products and consumer electronic devices, and sold worldwide in retail stores, it is usually understood that this technology has then entered the realm of mainstream technology and therefore mainstream industry. Such a leap however does not come cheap, as it has a double edge sword effect: first it becomes democratized and thus massively developed by numerous companies for various applications, but also it becomes a commodity, and thus gets under tremendous pressure to cut down its production and integration costs while not sacrificing to performance. We will show, based on numerous examples extracted from recent industry history, that the field of Diffractive Optics is about to undergo such a major transformation. Such a move has many impacts on all facets of digital diffractive optics technology, from the optical design houses to the micro-optics foundries (for both mastering and volume replication), to the final product integrators or contract manufacturers. The main causes of such a transformation are, as they have been for many other technologies in industry, successive technological bubbles which have carried and lifted up diffractive optics technology within the last decades. These various technological bubbles have been triggered either by real industry needs or by virtual investment hype. Both of these causes will be discussed in the paper. The adjective ""digital"" in "digital diffractive optics" does not refer only, as it is done in digital electronics, to the digital functionality of the element (digital signal processing), but rather to the digital way they are designed (by a digital computer) and fabricated (as wafer level optics using digital masking techniques). However, we can still trace a very strong similarity between the emergence of micro-electronics from analog electronics half a century ago, and the emergence of digital optics from conventional optics today.

  8. Modeling the Residual Stresses in Reactive Resins-Based Materials: a Case Study of Photo-Sensitive Composites for Dental Applications

    NASA Astrophysics Data System (ADS)

    Grassia, Luigi; D'Amore, Alberto

    2010-06-01

    Residual stresses in reactive resins-based composites are associated to the net volumetric contraction (shrinkage) arising during the cross-linking reactions. Depending on the restoration geometry (the ratio of the free surface area to the volume of the cavity) the frozen-in stresses can be as high as the strength of the dental composites. This is the main reason why the effectiveness and then the durability of restorations with composites remains quite lower than those realized with metal alloys based materials. In this paper we first explore the possibility to circumvent the mathematical complexity arising from the determination of residual stresses in reactive systems three-dimensionally constrained. Then, the results of our modeling approach are applied to a series of commercially available composites showing that almost all samples develop residual stresses such that the restoration undergoes failure as soon as it is realized.

  9. Modeling the Residual Stresses in Reactive Resins-Based Materials: a Case Study of Photo-Sensitive Composites for Dental Applications

    SciTech Connect

    Grassia, Luigi; D'Amore, Alberto

    2010-06-02

    Residual stresses in reactive resins-based composites are associated to the net volumetric contraction (shrinkage) arising during the cross-linking reactions. Depending on the restoration geometry (the ratio of the free surface area to the volume of the cavity) the frozen-in stresses can be as high as the strength of the dental composites. This is the main reason why the effectiveness and then the durability of restorations with composites remains quite lower than those realized with metal alloys based materials. In this paper we first explore the possibility to circumvent the mathematical complexity arising from the determination of residual stresses in reactive systems three-dimensionally constrained. Then, the results of our modeling approach are applied to a series of commercially available composites showing that almost all samples develop residual stresses such that the restoration undergoes failure as soon as it is realized.

  10. Calculating cellulose diffraction patterns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although powder diffraction of cellulose is a common experiment, the patterns are not widely understood. The theory is mathematical, there are numerous different crystal forms, and the conventions are not standardized. Experience with IR spectroscopy is not directly transferable. An awful error, tha...

  11. Diffraction with wavefront curvature

    NASA Astrophysics Data System (ADS)

    Nugent, K. A.; Peele, A. G.; Quiney, H. M.; Chapman, H. N.

    2005-05-01

    Modern X-ray optics can produce a focused synchrotron beam with curvature on a scale comparable to that of an isolated biomolecule or to the lattice spacing of a biomolecular crystal. It is demonstrated that diffraction of phase-curved beams from such systems allows unique and robust phase recovery.

  12. DIFFRACTION FROM MODEL CRYSTALS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although calculating X-ray diffraction patterns from atomic coordinates of a crystal structure is a widely available capability, calculation from non-periodic arrays of atoms has not been widely applied to cellulose. Non-periodic arrays result from modeling studies that, even though started with at...

  13. Diffract, then destroy

    NASA Astrophysics Data System (ADS)

    Ball, Philip

    2016-09-01

    A new implementation of X-ray diffraction using free-electron lasers can take snapshots of biological molecules that are inaccessible via X-ray crystallography. As Philip Ball reports, the technique can even be used to create stop-motion films of dynamic molecular processes

  14. Lightweight combustion residues-based structural materials for use in mines. Technical report, September 1--November 30, 1994

    SciTech Connect

    Chugh, Y.P.; Zhang, Y.; Ghosh, A.K.; Palmer, S.R.

    1994-12-31

    The overall goal of the project is to develop a 70--80 pcf, 2,500--3,000 psi-compressive-strength cellular concrete-type product from PCC fly ash, PCC bottom ash, and/or FBC spent bed ash alone or in suitable combination thereof. The developed combustion residue-based lightweight structural material will be used to replace wooden posts and crib members in underground mines. This report outlines the work completed in the first quarter of the project. The density gradient centrifuge (DGC) has been used to separate a power plant fly ash sample into fractions of different density. Each of the fly ash fractions obtained by DGC, an aliquot of the unseparated fly ash and an aliquot of a magnetic component of the fly ash, were digested in strong acids following the procedures outlined in ASTM 3050. Preliminary experiments have also been carried out to study the effect of mix proportions and curing regimes on the strength and density on the developed material. The DGC separation test reveals that most of the fly ash sample (approx. 90%) has a density above 1.9 g/cm{sup 3}. Indeed, nearly half of the sample has a density greater than 2.4 g/cm{sup 3}. Since only a very small amount of this fly ash has a reasonably low specific gravity, it appears unlikely at this time that enough low density material would be isolated to significantly enhance lightweight concrete production using fractionated material. A series of mixes have been made using fly ash, sodium silicate, cement, sand and water. Preliminary tests show that both cement and sodium silicate can be used as the binders to develop residues-based lightweight concrete. To date, compressive strength as high as 1,290 psi have been achieved with a density of 133 pcf, with 50 g of cement, 50 g of fly ash and 300 g of sand. Most of the work during the first quarter was done to understand the characteristics of the component materials.

  15. Production of 15N-Labelled Liquid Organic Fertilisers Based on Manure and Crop Residue for Use in Fertigation Studies.

    PubMed

    Martínez-Alcántara, Belén; Martínez-Cuenca, Mary-Rus; Fernández, Carlos; Legaz, Francisco; Quiñones, Ana

    2016-01-01

    Large quantities of crop residue and animal manure from agricultural and livestock activities are annually produced worldwide. With proper management, these residues are potentially valuable sources of plant nutrients, mainly N. Recycling such subproducts in sustainably-based agricultural systems can minimise the use of mineral fertilisers, and hence reduce the potential risk of surface and groundwater pollution. Therefore, the purpose of this study was to obtain (small scale) two liquid labelled-organic fertilisers, an animal- and a vegetal-based organic (AO and VO, respectively) fertiliser, to be used as organic N sources in subsequent fertigation studies. Forage maize (Zea mays L.) grown under 15N-labelled fertiliser supply was used as raw material for VO fertiliser production, and also as 15N-labelled sheep feed to obtain 15N-labelled manure. The labelled faeces fraction was used as raw material for the AO fertiliser. The VO fertiliser was obtained after an acidic and an enzyme-driven hydrolysis. The AO fertiliser was obtained after acidic hydrolysis. The VO liquid fertiliser presented an N concentration of 330 mg·L-1, 85% of total N was organic, while ammonium and nitrate N accounted for 55% and 45% of the mineral nitrogen fraction, respectively. This fertiliser also exhibited high K, Ca and S concentrations and notable values for the remaining macro- and micronutrients. The AO liquid fertiliser had a similar total N concentration (496 mg·L-1, 82% of total N in an organic form) to that of VO, but its mineral N fraction significantly differed, which came in a predominantly (95%) ammonia form. It also had a high content of N, P, K and other macronutrients, and sufficient Fe, Zn, Mn, Cu and B levels, which suggests its suitability as a potential fertiliser. The percentage of 15N enrichment in both VO and AO liquid fertilisers exceeded 2% 15N atom excess, which enabled their use in subsequent assays run to assess nitrogen uptake efficiency. PMID:26982183

  16. Production of 15N-Labelled Liquid Organic Fertilisers Based on Manure and Crop Residue for Use in Fertigation Studies

    PubMed Central

    Martínez-Alcántara, Belén; Martínez-Cuenca, Mary-Rus; Fernández, Carlos; Legaz, Francisco; Quiñones, Ana

    2016-01-01

    Large quantities of crop residue and animal manure from agricultural and livestock activities are annually produced worldwide. With proper management, these residues are potentially valuable sources of plant nutrients, mainly N. Recycling such subproducts in sustainably-based agricultural systems can minimise the use of mineral fertilisers, and hence reduce the potential risk of surface and groundwater pollution. Therefore, the purpose of this study was to obtain (small scale) two liquid labelled-organic fertilisers, an animal- and a vegetal-based organic (AO and VO, respectively) fertiliser, to be used as organic N sources in subsequent fertigation studies. Forage maize (Zea mays L.) grown under 15N-labelled fertiliser supply was used as raw material for VO fertiliser production, and also as 15N-labelled sheep feed to obtain 15N-labelled manure. The labelled faeces fraction was used as raw material for the AO fertiliser. The VO fertiliser was obtained after an acidic and an enzyme-driven hydrolysis. The AO fertiliser was obtained after acidic hydrolysis. The VO liquid fertiliser presented an N concentration of 330 mg·L-1, 85% of total N was organic, while ammonium and nitrate N accounted for 55% and 45% of the mineral nitrogen fraction, respectively. This fertiliser also exhibited high K, Ca and S concentrations and notable values for the remaining macro- and micronutrients. The AO liquid fertiliser had a similar total N concentration (496 mg·L-1, 82% of total N in an organic form) to that of VO, but its mineral N fraction significantly differed, which came in a predominantly (95%) ammonia form. It also had a high content of N, P, K and other macronutrients, and sufficient Fe, Zn, Mn, Cu and B levels, which suggests its suitability as a potential fertiliser. The percentage of 15N enrichment in both VO and AO liquid fertilisers exceeded 2% 15N atom excess, which enabled their use in subsequent assays run to assess nitrogen uptake efficiency. PMID:26982183

  17. Radiometric analysis of diffraction

    NASA Astrophysics Data System (ADS)

    Castañeda, R.; Betancur, R.; Herrera, J.; Carrasquilla, J.

    2008-04-01

    A description of Fresnel and Fraunhofer diffraction of quasi-homogenous optical fields in any state of spatial coherence is presented, which clearly differs from the classical formalism. Instead of the propagation of the cross-spectral density from the diffracting aperture to the observation plane, the diffracting aperture is regarded as a planar quasi-homogeneous source, whose generalised radiance is carried by the spatial coherence wavelets, and the power distribution at the observation plane is expressed in terms of the generalised radiant intensity. It allows interpreting the negative values of the generalised radiance as "negative energies" emitted along specific directions and subjected to the achievement of the conservation law of energy. This interpretation is not evident in the classical formalism. Consequently, interference can be thought as resulting of energy transfer over a given wavefront, due to the addition of equal amounts of "positive" and "negative" energies, along specific directions, to the contributions provided by the individual radiators of the radiant source. In this sense, the radiant flux from the source, which is provided only by the individual contributions, is redistributed depending on the spatial coherence properties of the field. This redistribution characterises the diffraction phenomenon. It is also shown that the supports of the complex degree of spatial coherence near the aperture edge are vignetted by the edge. This feature is a cause for the generalised radiance providing "negative energies", and constitutes the actual effect of the edge on diffraction. The approach is validated by the close concordance between the numerical and the experimental results, which should be regarded as a proof of the physical existence of the spatial coherence wavelets.

  18. Monoclonal antibody-based ELISA and colloidal gold-based immunochromatographic assay for streptomycin residue detection in milk and swine urine*

    PubMed Central

    Wu, Jian-xiang; Zhang, Shao-en; Zhou, Xue-ping

    2010-01-01

    A protein conjugate of streptomycin (streptomycin-bovine serum albumin (BSA) conjugate) was prepared and used as immunogen to produce monoclonal antibodies (MAb). One hybridoma secreting anti-streptomycin MAb was obtained and then used to produce MAb. The MAb named 13H5 showed the 50% maximal inhibitory concentration (IC50) value of 4.65 ng/ml and the IC20 value of 0.21 ng/ml in phosphate buffered saline (PBS). At optimum conditions, an indirect competitive enzyme-linked immunosorbent assay (ELISA) and a colloidal gold-based immunochromatographic assay (CGIA) were developed and applied to detect streptomycin residues in milk and swine urine samples. The developed ELISA showed that the minimum detection limit was 2.0 and 1.9 ng/ml for milk and swine urine samples, respectively, without obvious cross-reactivity to other tested antibiotics except dihydrostreptomycin which gave a 118.32% cross reaction value. Milk and swine urine samples spiked with streptomycin at 10, 50, 100 and 200 ng/ml were analyzed by the established ELISA. The mean recovery of streptomycin was from 81.9% to 105.5% and from 84.3% to 92.2% for milk and swine urine, respectively. The optimized CGIA showed that the minimum detection limit was 20.0 ng/ml for milk and swine urine samples. The results of spiked analysis and specific analysis demonstrate that the CGIA could be applicable for screening milk and swine urine samples for the presence of streptomycin residues on-site. The established ELISA and CGIA allow the rapid, low-cost, and sensitive determination of streptomycin residues in food samples. PMID:20043352

  19. Diffraction Techniques in Structural Biology

    PubMed Central

    Egli, Martin

    2010-01-01

    A detailed understanding of chemical and biological function and the mechanisms underlying the activities ultimately requires atomic-resolution structural data. Diffraction-based techniques such as single-crystal X-ray crystallography, electron microscopy and neutron diffraction are well established and have paved the road to the stunning successes of modern-day structural biology. The major advances achieved in the last 20 years in all aspects of structural research, including sample preparation, crystallization, the construction of synchrotron and spallation sources, phasing approaches and high-speed computing and visualization, now provide specialists and non-specialists alike with a steady flow of molecular images of unprecedented detail. The present chapter combines a general overview of diffraction methods with a step-by-step description of the process of a single-crystal X-ray structure determination experiment, from chemical synthesis or expression to phasing and refinement, analysis and quality control. For novices it may serve as a stepping-stone to more in-depth treatises of the individual topics. Readers relying on structural information for interpreting functional data may find it a useful consumer guide. PMID:20517991

  20. Residue Geometry Networks: A Rigidity-Based Approach to the Amino Acid Network and Evolutionary Rate Analysis

    PubMed Central

    Fokas, Alexander S.; Cole, Daniel J.; Ahnert, Sebastian E.; Chin, Alex W.

    2016-01-01

    Amino acid networks (AANs) abstract the protein structure by recording the amino acid contacts and can provide insight into protein function. Herein, we describe a novel AAN construction technique that employs the rigidity analysis tool, FIRST, to build the AAN, which we refer to as the residue geometry network (RGN). We show that this new construction can be combined with network theory methods to include the effects of allowed conformal motions and local chemical environments. Importantly, this is done without costly molecular dynamics simulations required by other AAN-related methods, which allows us to analyse large proteins and/or data sets. We have calculated the centrality of the residues belonging to 795 proteins. The results display a strong, negative correlation between residue centrality and the evolutionary rate. Furthermore, among residues with high closeness, those with low degree were particularly strongly conserved. Random walk simulations using the RGN were also successful in identifying allosteric residues in proteins involved in GPCR signalling. The dynamic function of these residues largely remain hidden in the traditional distance-cutoff construction technique. Despite being constructed from only the crystal structure, the results in this paper suggests that the RGN can identify residues that fulfil a dynamical function. PMID:27623708

  1. Residue Geometry Networks: A Rigidity-Based Approach to the Amino Acid Network and Evolutionary Rate Analysis.

    PubMed

    Fokas, Alexander S; Cole, Daniel J; Ahnert, Sebastian E; Chin, Alex W

    2016-01-01

    Amino acid networks (AANs) abstract the protein structure by recording the amino acid contacts and can provide insight into protein function. Herein, we describe a novel AAN construction technique that employs the rigidity analysis tool, FIRST, to build the AAN, which we refer to as the residue geometry network (RGN). We show that this new construction can be combined with network theory methods to include the effects of allowed conformal motions and local chemical environments. Importantly, this is done without costly molecular dynamics simulations required by other AAN-related methods, which allows us to analyse large proteins and/or data sets. We have calculated the centrality of the residues belonging to 795 proteins. The results display a strong, negative correlation between residue centrality and the evolutionary rate. Furthermore, among residues with high closeness, those with low degree were particularly strongly conserved. Random walk simulations using the RGN were also successful in identifying allosteric residues in proteins involved in GPCR signalling. The dynamic function of these residues largely remain hidden in the traditional distance-cutoff construction technique. Despite being constructed from only the crystal structure, the results in this paper suggests that the RGN can identify residues that fulfil a dynamical function.

  2. Residue Geometry Networks: A Rigidity-Based Approach to the Amino Acid Network and Evolutionary Rate Analysis

    NASA Astrophysics Data System (ADS)

    Fokas, Alexander S.; Cole, Daniel J.; Ahnert, Sebastian E.; Chin, Alex W.

    2016-09-01

    Amino acid networks (AANs) abstract the protein structure by recording the amino acid contacts and can provide insight into protein function. Herein, we describe a novel AAN construction technique that employs the rigidity analysis tool, FIRST, to build the AAN, which we refer to as the residue geometry network (RGN). We show that this new construction can be combined with network theory methods to include the effects of allowed conformal motions and local chemical environments. Importantly, this is done without costly molecular dynamics simulations required by other AAN-related methods, which allows us to analyse large proteins and/or data sets. We have calculated the centrality of the residues belonging to 795 proteins. The results display a strong, negative correlation between residue centrality and the evolutionary rate. Furthermore, among residues with high closeness, those with low degree were particularly strongly conserved. Random walk simulations using the RGN were also successful in identifying allosteric residues in proteins involved in GPCR signalling. The dynamic function of these residues largely remain hidden in the traditional distance-cutoff construction technique. Despite being constructed from only the crystal structure, the results in this paper suggests that the RGN can identify residues that fulfil a dynamical function.

  3. Residue Geometry Networks: A Rigidity-Based Approach to the Amino Acid Network and Evolutionary Rate Analysis.

    PubMed

    Fokas, Alexander S; Cole, Daniel J; Ahnert, Sebastian E; Chin, Alex W

    2016-01-01

    Amino acid networks (AANs) abstract the protein structure by recording the amino acid contacts and can provide insight into protein function. Herein, we describe a novel AAN construction technique that employs the rigidity analysis tool, FIRST, to build the AAN, which we refer to as the residue geometry network (RGN). We show that this new construction can be combined with network theory methods to include the effects of allowed conformal motions and local chemical environments. Importantly, this is done without costly molecular dynamics simulations required by other AAN-related methods, which allows us to analyse large proteins and/or data sets. We have calculated the centrality of the residues belonging to 795 proteins. The results display a strong, negative correlation between residue centrality and the evolutionary rate. Furthermore, among residues with high closeness, those with low degree were particularly strongly conserved. Random walk simulations using the RGN were also successful in identifying allosteric residues in proteins involved in GPCR signalling. The dynamic function of these residues largely remain hidden in the traditional distance-cutoff construction technique. Despite being constructed from only the crystal structure, the results in this paper suggests that the RGN can identify residues that fulfil a dynamical function. PMID:27623708

  4. Vegetable fibres from agricultural residues as thermo-mechanical reinforcement in recycled polypropylene-based green foams.

    PubMed

    Ardanuy, Mònica; Antunes, Marcelo; Velasco, José Ignacio

    2012-02-01

    Novel lightweight composite foams based on recycled polypropylene reinforced with cellulosic fibres obtained from agricultural residues were prepared and characterized. These composites, initially prepared by melt-mixing recycled polypropylene with variable fibre concentrations (10-25 wt.%), were foamed by high-pressure CO(2) dissolution, a clean process which avoids the use of chemical blowing agents. With the aim of studying the influence of the fibre characteristics on the resultant foams, two chemical treatments were applied to the barley straw in order to increase the α-cellulose content of the fibres. The chemical composition, morphology and thermal stability of the fibres and composites were analyzed. Results indicate that fibre chemical treatment and later foaming of the composites resulted in foams with characteristic closed-cell microcellular structures, their specific storage modulus significantly increasing due to the higher stiffness of the fibres. The addition of the fibres also resulted in an increase in the glass transition temperature of PP in both the solid composites and more significantly in the foams.

  5. Occurrence of Natural Bacillus thuringiensis Contaminants and Residues of Bacillus thuringiensis-Based Insecticides on Fresh Fruits and Vegetables

    PubMed Central

    Frederiksen, Kristine; Rosenquist, Hanne; Jørgensen, Kirsten; Wilcks, Andrea

    2006-01-01

    A total of 128 Bacillus cereus-like strains isolated from fresh fruits and vegetables for sale in retail shops in Denmark were characterized. Of these strains, 39% (50/128) were classified as Bacillus thuringiensis on the basis of their content of cry genes determined by PCR or crystal proteins visualized by microscopy. Random amplified polymorphic DNA analysis and plasmid profiling indicated that 23 of the 50 B. thuringiensis strains were of the same subtype as B. thuringiensis strains used as commercial bioinsecticides. Fourteen isolates were indistinguishable from B. thuringiensis subsp. kurstaki HD1 present in the products Dipel, Biobit, and Foray, and nine isolates grouped with B. thuringiensis subsp. aizawai present in Turex. The commercial strains were primarily isolated from samples of tomatoes, cucumbers, and peppers. A multiplex PCR method was developed to simultaneously detect all three genes in the enterotoxin hemolysin BL (HBL) and the nonhemolytic enterotoxin (NHE), respectively. This revealed that the frequency of these enterotoxin genes was higher among the strains indistinguishable from the commercial strains than among the other B. thuringiensis and B. cereus-like strains isolated from fruits and vegetables. The same was seen for a third enterotoxin, CytK. In conclusion, the present study strongly indicates that residues of B. thuringiensis-based insecticides can be found on fresh fruits and vegetables and that these are potentially enterotoxigenic. PMID:16672488

  6. Group-based citizenship in the acceptance of indoor residual spraying (IRS) for malaria control in Mozambique.

    PubMed

    Montgomery, Catherine M; Munguambe, Khátia; Pool, Robert

    2010-05-01

    In 2006, the Mozambican Ministry of Health expanded its existing Indoor Residual Spraying (IRS) programme into Manhiça District in the south of the country. Widespread household coverage is required to have a significant impact on malaria transmission, making acceptability fundamental to success. Between 2006 and 2008 we conducted anthropological research in order to understand acceptability of IRS in the context of the implementation process, policy debates, local and regional politics and historical processes. In the first phase of this qualitative study, conducted between January and April 2006, 73 interviews and 12 focus groups were conducted with key stakeholders from 14 locales in and around the town of Manhiça: householders, community leaders, health care professionals, sprayers, and District officials. Analysis revealed IRS to be broadly acceptable despite very low levels of perceived efficacy and duration of effect. In contrast to previous studies which have linked acceptance to a reduction in mosquitoes, nuisance biting and malaria, we found people's compliance with the programme to be founded on a sense of group-based citizenship. The involvement of local governmental leaders in the intervention appears to have led many to accept spraying as part of their civic duty, as decreed by post-war decentralisation policy in rural areas. We discuss the implications of this 'passive' form of compliance for the acceptability and sustainability of malaria control and other public health programmes.

  7. Immobilization of tetracyclines in manure and manure-amended soils using aluminum-based drinking water treatment residuals.

    PubMed

    Punamiya, Pravin; Sarkar, Dibyendu; Rakshit, Sudipta; Elzinga, Evert J; Datta, Rupali

    2016-02-01

    Veterinary antibiotics (VAs) are emerging contaminants of concern in the environment, mainly due to the potential for development of antibiotic-resistant bacteria and effect on microbiota that could interfere with crucial ecosystem functions such as nutrient cycling and decomposition. High levels of VAs such as tetracyclines (TCs) have been reported in agricultural soils amended with manure, which also has the potential to cause surface and groundwater contamination. Several recent studies have focused on developing methods to immobilize VAs such as composting with straw, hardwood chips, commercial biochar, aeration, mixing, heat treatment, etc. The major shortcomings of these methods include high cost and limited effectiveness. In the current study, we assessed the effectiveness of aluminum-based drinking water treatment residuals (Al-WTR) as a "green" sorbent to immobilize TCs in manure and manure-applied soils with varying physicochemical properties by laboratory incubation study. Results show that Al-WTR is very effective in immobilizing tetracycline (TTC) and oxytetracycline (OTC). The presence of phosphate resulted in significant (p < 0.01) decrease in TTC/OTC sorption by Al-WTR, but the presence of sulfate did not. attenuated total reflection (ATR)-FTIR spectroscopy indicate that TTC and OTC likely forming surface complexes via inner-sphere-type bonds in soils, manure, and manure-applied soils amended with Al-WTR.

  8. ASCORBIC ACID TREATMENT TO REDUCE RESIDUAL HALOGEN-BASED OXIDANTS PRIOR TO THE DETERMINATION OF HALOGENATED DISINFECTION BYPRODUCTS IN POTABLE WATER

    EPA Science Inventory

    Treatment of potable water samples with ascorbic acid has been investigated as a means for reducing residual halogen-based oxidants (disinfectants)i.e., HOCl, Cl2, Brw and BrCl, prior to determination of EPA Method 551.1A and 551.1B analytes. These disinfection byproducts include...

  9. Small area analysis using micro-diffraction techniques

    SciTech Connect

    GOEHNER,RAYMOND P.; TISSOT JR.,RALPH G.; MICHAEL,JOSEPH R.

    2000-02-11

    An overall trend toward smaller electronic packages and devices makes it increasingly important and difficult to obtain meaningful diffraction information from small areas. X-ray micro-diffraction, electron back-scattered diffraction (EBSD) and Kossel are micro-diffraction techniques used for crystallographic analysis including texture, phase identification and strain measurements. X-ray micro-diffraction primarily is used for phase analysis and residual strain measurements. X-ray micro-diffraction primarily is used for phase analysis and residual strain measurements of areas between 10 {micro}m to 100 {micro}m. For areas this small glass capillary optics are used for producing a usable collimated x-ray beam. These optics are designed to reflect x-rays below the critical angle therefore allowing for larger solid acceptance angle at the x-ray source resulting in brighter smaller x-ray beams. The determination of residual strain using micro-diffraction techniques is very important to the semiconductor industry. Residual stresses have caused voiding of the interconnect metal which then destroys electrical continuity. Being able to determine the residual stress helps industry to predict failures from the aging effects of interconnects due to this stress voiding. Stress measurements would be impossible using a conventional x-ray diffractometer; however, utilizing a 30{micro}m glass capillary these small areas are readily assessable for analysis. Kossel produces a wide angle diffraction pattern from fluorescent x-rays generated in the sample by an e-beam in a SEM. This technique can yield very precise lattice parameters for determining strain. Fig. 2 shows a Kossel pattern from a Ni specimen. Phase analysis on small areas is also possible using an energy dispersive spectrometer (EBSD) and x-ray micro-diffraction techniques. EBSD has the advantage of allowing the user to observe the area of interest using the excellent imaging capabilities of the SEM. An EDS detector has

  10. Colored Diffraction Catastrophes

    NASA Astrophysics Data System (ADS)

    Berry, M. V.; Klein, S.

    1996-03-01

    On fine scales, caustics produced with white light show vividly colored diffraction fringes. For caustics described by the elementary catastrophes of singularity theory, the colors are characteristic of the type of singularity. We study the diffraction colors of the fold and cusp catastrophes. The colors can be simulated computationally as the superposition of monochromatic patterns for different wavelengths. Far from the caustic, where the luminosity contrast is negligible, the fringe colors persist; an asymptotic theory explains why. Experiments with caustics produced by refraction through irregular bathroom-window glass show good agreement with theory. Colored fringes near the cusp reveal fine lines that are not present in any of the monochromatic components; these lines are explained in terms of partial decoherence between rays with widely differing path differences.

  11. Colored diffraction catastrophes.

    PubMed Central

    Berry, M V; Klein, S

    1996-01-01

    On fine scales, caustics produced with white light show vividly colored diffraction fringes. For caustics described by the elementary catastrophes of singularity theory, the colors are characteristic of the type of singularity. We study the diffraction colors of the fold and cusp catastrophes. The colors can be simulated computationally as the superposition of monochromatic patterns for different wavelengths. Far from the caustic, where the luminosity contrast is negligible, the fringe colors persist; an asymptotic theory explains why. Experiments with caustics produced by refraction through irregular bathroom-window glass show good agreement with theory. Colored fringes near the cusp reveal fine lines that are not present in any of the monochromatic components; these lines are explained in terms of partial decoherence between rays with widely differing path differences. Images Fig. 1 Fig. 2 Fig. 3 Fig. 6 Fig. 8 Fig. 9 Fig. 10 PMID:11607642

  12. In vitro ability of beer fermentation residue and yeast-based products to bind aflatoxin B1.

    PubMed

    Bovo, Fernanda; Franco, Larissa Tuanny; Rosim, Roice Eliana; Barbalho, Ricardo; de Oliveira, Carlos Augusto Fernandes

    2015-06-01

    This study aimed to verify the in vitro ability of beer fermentation residue (BFR) containing Saccharomyces cerevisiae cells and five commercial products that differed in the viability and integrity of S. cerevisiae cells to remove aflatoxin B1 (AFB1) from a citrate-phosphate buffer solution (CPBS). BFR was collected at a microbrewery and prepared by drying and milling. The commercial yeast-based products were as follows: inactive intact yeast cells from beer alcoholic fermentation, inactive intact yeast cells from sugarcane alcoholic fermentation, hydrolyzed yeast cells, yeast cell walls and active yeast cells. Adsorption assays were performed in CPBS spiked with 1.0 μg AFB1/mL at pH 3.0 and 6.0 for a contact time of 60 min at room temperature. Analysis of AFB1 in the samples was performed by high performance liquid chromatography. AFB1 adsorption by the products ranged from 45.5% to 69.4% at pH 3.0 and from 24.0% to 63.8% at pH 6.0. The higher percentages (p < 0.05) of AFB1 binding at both pH values were achieved with products containing hydrolyzed yeast cells or yeast cell walls rather than intact cells. The AFB1 binding percentages of BFR were 55.0 ± 5.0% at pH 3.0 and 49.2 ± 4.5% at pH 6.0, which was not significantly different (p > 0.05) from commercial products containing inactive intact yeast cells. The results of this trial indicate that the yeast-based products tested, especially the BFR, have potential applications in animal feeds as a suitable biological method for reducing the adverse effects of aflatoxins.

  13. In vitro ability of beer fermentation residue and yeast-based products to bind aflatoxin B1.

    PubMed

    Bovo, Fernanda; Franco, Larissa Tuanny; Rosim, Roice Eliana; Barbalho, Ricardo; de Oliveira, Carlos Augusto Fernandes

    2015-06-01

    This study aimed to verify the in vitro ability of beer fermentation residue (BFR) containing Saccharomyces cerevisiae cells and five commercial products that differed in the viability and integrity of S. cerevisiae cells to remove aflatoxin B1 (AFB1) from a citrate-phosphate buffer solution (CPBS). BFR was collected at a microbrewery and prepared by drying and milling. The commercial yeast-based products were as follows: inactive intact yeast cells from beer alcoholic fermentation, inactive intact yeast cells from sugarcane alcoholic fermentation, hydrolyzed yeast cells, yeast cell walls and active yeast cells. Adsorption assays were performed in CPBS spiked with 1.0 μg AFB1/mL at pH 3.0 and 6.0 for a contact time of 60 min at room temperature. Analysis of AFB1 in the samples was performed by high performance liquid chromatography. AFB1 adsorption by the products ranged from 45.5% to 69.4% at pH 3.0 and from 24.0% to 63.8% at pH 6.0. The higher percentages (p < 0.05) of AFB1 binding at both pH values were achieved with products containing hydrolyzed yeast cells or yeast cell walls rather than intact cells. The AFB1 binding percentages of BFR were 55.0 ± 5.0% at pH 3.0 and 49.2 ± 4.5% at pH 6.0, which was not significantly different (p > 0.05) from commercial products containing inactive intact yeast cells. The results of this trial indicate that the yeast-based products tested, especially the BFR, have potential applications in animal feeds as a suitable biological method for reducing the adverse effects of aflatoxins. PMID:26273277

  14. In vitro ability of beer fermentation residue and yeast-based products to bind aflatoxin B1

    PubMed Central

    Bovo, Fernanda; Franco, Larissa Tuanny; Rosim, Roice Eliana; Barbalho, Ricardo; de Oliveira, Carlos Augusto Fernandes

    2015-01-01

    This study aimed to verify the in vitro ability of beer fermentation residue (BFR) containing Saccharomyces cerevisiae cells and five commercial products that differed in the viability and integrity of S. cerevisiae cells to remove aflatoxin B1 (AFB1) from a citrate-phosphate buffer solution (CPBS). BFR was collected at a microbrewery and prepared by drying and milling. The commercial yeast-based products were as follows: inactive intact yeast cells from beer alcoholic fermentation, inactive intact yeast cells from sugarcane alcoholic fermentation, hydrolyzed yeast cells, yeast cell walls and active yeast cells. Adsorption assays were performed in CPBS spiked with 1.0 μg AFB1/mL at pH 3.0 and 6.0 for a contact time of 60 min at room temperature. Analysis of AFB1 in the samples was performed by high performance liquid chromatography. AFB1 adsorption by the products ranged from 45.5% to 69.4% at pH 3.0 and from 24.0% to 63.8% at pH 6.0. The higher percentages (p < 0.05) of AFB1 binding at both pH values were achieved with products containing hydrolyzed yeast cells or yeast cell walls rather than intact cells. The AFB1 binding percentages of BFR were 55.0 ± 5.0% at pH 3.0 and 49.2 ± 4.5% at pH 6.0, which was not significantly different (p > 0.05) from commercial products containing inactive intact yeast cells. The results of this trial indicate that the yeast-based products tested, especially the BFR, have potential applications in animal feeds as a suitable biological method for reducing the adverse effects of aflatoxins. PMID:26273277

  15. Dual-layer solid-phase extraction based on molecular imprinting technology: Seeking a route to enhance selectivity for trace analysis of pesticide residues in olive oil.

    PubMed

    Garcia, Raquel; Carreiro, Elisabete P; Nunes, José; da Silva, Marco Gomes; Freitas, Ana Maria Costa; Burke, Anthony J; Cabrita, Maria João

    2016-07-01

    Aiming to introduce a multiresidue analysis for the trace detection of pesticide residues belonging to organophosphorus and triazine classes from olive oil samples, a new sample preparation methodology comprising the use of a dual layer of "tailor-made" molecularly imprinted polymers (MIPs) SPE for the simultaneous extraction of both pesticides in a single procedure has been attempted. This work has focused on the implementation of a dual MIP-layer SPE procedure (DL-MISPE) encompassing the use of two MIP layers as specific sorbents. In order to achieve higher recovery rates, the amount of MIP layers has been optimized as well as the influence of MIP packaging order. The optimized DL-MISPE approach has been used in the preconcentration of spiked organic olive oil samples with concentrations of dimethoate and terbuthylazine similar to the maximum residue limits and further quantification by HPLC. High recovery rates for dimethoate (95%) and terbuthylazine (94%) have been achieved with good accuracy and precision. Overall, this work constitutes the first attempt on the development of a dual pesticide residue methodology for the trace analysis of pesticide residues based on molecular imprinting technology. Thus, DL-MISPE constitutes a reliable, robust, and sensitive sample preparation methodology that enables preconcentration of the target pesticides in complex olive oil samples, even at levels similar to the maximum residue limits enforced by the legislation.

  16. Dual-layer solid-phase extraction based on molecular imprinting technology: Seeking a route to enhance selectivity for trace analysis of pesticide residues in olive oil.

    PubMed

    Garcia, Raquel; Carreiro, Elisabete P; Nunes, José; da Silva, Marco Gomes; Freitas, Ana Maria Costa; Burke, Anthony J; Cabrita, Maria João

    2016-07-01

    Aiming to introduce a multiresidue analysis for the trace detection of pesticide residues belonging to organophosphorus and triazine classes from olive oil samples, a new sample preparation methodology comprising the use of a dual layer of "tailor-made" molecularly imprinted polymers (MIPs) SPE for the simultaneous extraction of both pesticides in a single procedure has been attempted. This work has focused on the implementation of a dual MIP-layer SPE procedure (DL-MISPE) encompassing the use of two MIP layers as specific sorbents. In order to achieve higher recovery rates, the amount of MIP layers has been optimized as well as the influence of MIP packaging order. The optimized DL-MISPE approach has been used in the preconcentration of spiked organic olive oil samples with concentrations of dimethoate and terbuthylazine similar to the maximum residue limits and further quantification by HPLC. High recovery rates for dimethoate (95%) and terbuthylazine (94%) have been achieved with good accuracy and precision. Overall, this work constitutes the first attempt on the development of a dual pesticide residue methodology for the trace analysis of pesticide residues based on molecular imprinting technology. Thus, DL-MISPE constitutes a reliable, robust, and sensitive sample preparation methodology that enables preconcentration of the target pesticides in complex olive oil samples, even at levels similar to the maximum residue limits enforced by the legislation. PMID:27062483

  17. Multiple wavelength diffractive imaging

    NASA Astrophysics Data System (ADS)

    Chen, Bo; Dilanian, Ruben A.; Teichmann, Sven; Abbey, Brian; Peele, Andrew G.; Williams, Garth J.; Hannaford, Peter; van Dao, Lap; Quiney, Harry M.; Nugent, Keith A.

    2009-02-01

    We demonstrate coherent diffraction imaging using multiple harmonics from a high-harmonic generation source. An algorithm is presented that builds the known incident spectrum into the reconstruction procedure with the result that the useable flux is increased by more than an order of magnitude. Excellent images are obtained with a resolution of (165±5)nm and compare very well with images from a scanning electron microscope.

  18. Polychromatic diffraction contrast tomography

    SciTech Connect

    King, A.; Reischig, P.; Adrien, J.; Peetermans, S.; Ludwig, W.

    2014-11-15

    This tutorial review introduces the use of polychromatic radiation for 3D grain mapping using X-ray diffraction contrast tomography. The objective is to produce a 3D map of the grain shapes and orientations within a bulk, millimeter-sized polycrystalline sample. The use of polychromatic radiation enables the standard synchrotron X-ray technique to be applied in a wider range of contexts: 1) Using laboratory X-ray sources allows a much wider application of the diffraction contrast tomography technique. 2) Neutron sources allow large samples, or samples containing high Z elements to be studied. 3) Applied to synchrotron sources, smaller samples may be treated, or faster measurements may be possible. Challenges and particularities in the data acquisition and processing, and the limitations of the different variants, are discussed. - Highlights: • We present a tutorial review of polychromatic diffraction contrast tomography techniques. • The use of polychromatic radiation allows the standard synchrotron DCT technique to be extended to a range of other sources. • The characteristics and limitations of all variants of the techniques are derived, discussed and compared. • Examples using laboratory X-ray and cold neutron radiation are presented. • Suggestions for the future development of these techniques are presented.

  19. FESDIF -- Finite Element Scalar Diffraction theory code

    SciTech Connect

    Kraus, H.G.

    1992-09-01

    This document describes the theory and use of a powerful scalar diffraction theory based computer code for calculation of intensity fields due to diffraction of optical waves by two-dimensional planar apertures and lenses. This code is called FESDIF (Finite Element Scalar Diffraction). It is based upon both Fraunhofer and Kirchhoff scalar diffraction theories. Simplified routines for circular apertures are included. However, the real power of the code comes from its basis in finite element methods. These methods allow the diffracting aperture to be virtually any geometric shape, including the various secondary aperture obstructions present in telescope systems. Aperture functions, with virtually any phase and amplitude variations, are allowed in the aperture openings. Step change aperture functions are accommodated. The incident waves are considered to be monochromatic. Plane waves, spherical waves, or Gaussian laser beams may be incident upon the apertures. Both area and line integral transformations were developed for the finite element based diffraction transformations. There is some loss of aperture function generality in the line integral transformations which are typically many times more computationally efficient than the area integral transformations when applicable to a particular problem.

  20. Quantitative evaluation of residual torque of a loose bolt based on wave energy dissipation and vibro-acoustic modulation: A comparative study

    NASA Astrophysics Data System (ADS)

    Zhang, Zhen; Liu, Menglong; Su, Zhongqing; Xiao, Yi

    2016-11-01

    A wave energy dissipation (WED)-based linear acoustic approach and a vibro-acoustic modulation (VM)-based nonlinear method were developed comparatively, for detecting bolt loosening in bolted joints and subsequently evaluating the residual torque of the loose bolt. For WED-based, an analytical model residing on the Hertzian contact theory was established, whereby WED was linked to the residual torque of a loose bolt, contributing to a linear index. For VM-based, contact acoustic nonlinearity (CAN) engendered at the joining interface, when a pumping vibration perturbs a probing wave, was interrogated, and the nonlinear contact stiffness was described in terms of a Taylor series, on which basis a nonlinear index was constructed to associate spectral features with the residual torque. Based respectively on a linear and a nonlinear premise, the two indices were validated experimentally, and the results well coincided with theoretical predication. Quantitative comparison of the two indices surmises that the VM-based nonlinear method outperforms the WED-based linear approach in terms of sensitivity and accuracy, and particularly when the bolt loosening is in its embryo stage. In addition, the detectability of the nonlinear index is not restricted by the type of the joint, against a high dependence of its linear counterpart on the joint type.