Science.gov

Sample records for achieving uniform surface

  1. The Relationship of School Uniforms to Student Attendance, Achievement, and Discipline

    ERIC Educational Resources Information Center

    Sowell, Russell Edward

    2012-01-01

    This causal-comparative study examined the relationship of school uniforms to attendance, academic achievement, and discipline referral rates, using data collected from two high schools in rural southwest Georgia county school systems, one with a uniforms program and one without a uniforms program. After accounting for race and students with…

  2. The Relationship of School Uniforms to Student Attendance, Achievement, and Discipline

    ERIC Educational Resources Information Center

    Sowell, Russell Edward

    2012-01-01

    This causal-comparative study examined the relationship of school uniforms to attendance, academic achievement, and discipline referral rates, using data collected from two high schools in rural southwest Georgia county school systems, one with a uniforms program and one without a uniforms program. After accounting for race and students with…

  3. Achieving large uniform tensile ductility in nanocrystalline metals.

    PubMed

    Wang, Y M; Ott, R T; Hamza, A V; Besser, M F; Almer, J; Kramer, M J

    2010-11-19

    Synchrotron x-ray diffraction and high-resolution electron microscopy revealed the origin of different strain hardening behaviors (and dissimilar tensile ductility) in nanocrystalline Ni and nanocrystalline Co. Planar defect accumulations and texture evolution were observed in Co but not in Ni, suggesting that interfacial defects are an effective passage to promote strain hardening in truly nanograins. Twinning becomes less significant in Co when grain sizes reduce to below ~15 nm. This study offers insights into achieving excellent mechanical properties in nanocrystalline materials.

  4. Effects of Student Uniforms on Attendance, Behavior Problems, Substance Use, and Academic Achievement.

    ERIC Educational Resources Information Center

    Brunsma, David L.; Rockquemore, Kerry A.

    1998-01-01

    Examined 10th-grade data from the 1988 National Educational Longitudinal Study to investigate the effects of school uniforms on student attendance, behavior problems, substance use, and academic achievement. Data from public, private, and Catholic schools indicated that uniforms had no direct effect on substance use, attendance, or behavior, and a…

  5. Achieving High Rates and High Uniformity in Copper Chemical Mechanical Polishing

    NASA Astrophysics Data System (ADS)

    Nolan, Lucy Marjorie

    The chemical mechanical polishing of Copper (Cu-CMP) is a complex and poorly understood process. Despite this, it is widely used throughout the semiconductor and microelectronics industries, and makes up a significant portion of wafer processing costs. In these contexts, desirable polishing outcomes such as a high rate of removal from the copper surface, and high removal rate uniformity, are achieved largely by trial-and-error. In this study, the same outcomes are pursued through a systematic investigation of polishing lubrication characteristics and abrasive and oxidiser concentrations in the polishing slurry. A strong link between lubrication characteristics, quantified by the dimensionless Sommerfield number, and the uniformity of polishing is demonstrated. A mechanism for the observed relationship is proposed, based on an adaptation of hydrodynamic lubrication theory. The overall rate of removal is maximized by polishing in a slurry containing oxidiser and abrasives in a synergistic ratio. Polishing away from this ratio has additional effects on the overall quality of the surface produced. Transport of slurry across the polishing pad is investigated by using tracers; the results demonstrate that slurry usage can be reduced in many circumstances with no impact on overall polishing outcomes, reducing overall processing costs. These findings are combined to design a polishing process, with good results.

  6. Uniform algal growth in photobioreactors using surface scatterers

    NASA Astrophysics Data System (ADS)

    Ahsan, Syed S.; Pereyra, Brandon; Erickson, David

    2014-03-01

    Cultures of algae, such as cyanobacteria, are a promising source of renewable energy. However, algal growth is highly dependent on light intensity and standard photobioreactors do a poor job of distributing light uniformly for algal utilization due to shading effects in dense algal cultures. Engineered scattering schemes are already employed in current slab-waveguide technologies, like edge-lit LEDs. Stacking such slab-waveguides that uniformly distribute light could potentially yield photobioreactors to overcome the shading effect and grow extremely high densities of algal cultures that would lower monetary and energetic costs. Here, we characterize and design a scattering scheme for specific application within photobioreactors which employs a gradient distribution of surface scatterers with uniform lateral scattering intensity. This uniform scattering scheme is shown to be superior for algal cultivation.

  7. Note: Continuous synthesis of uniform vertical graphene on cylindrical surfaces.

    PubMed

    Bo, Zheng; Cui, Shumao; Yu, Kehan; Lu, Ganhua; Mao, Shun; Chen, Junhong

    2011-08-01

    This note describes a new reactor design for continuous synthesis of vertically oriented graphene (VG) sheets on cylindrical wire substrates using an atmospheric plasma-enhanced chemical vapor deposition (PECVD) system. Through combining a U-shaped reactor design with "dynamic mode" synthesis featuring simultaneous rotational and axial movements of the metallic wire substrate, the new setup can enable continuous synthesis of VG sheets on the wire surface with remarkable uniformity in both circumferential and axial directions. In contrast, synthesis of VG at "static mode" with a fixed substrate can only lead to non-uniform growth of VG sheets on the wire surface. Potential applications of the resulting uniform-VG-coated metallic wire could include field emitters, field-ionization-based neutral atom detectors, and indoor corona discharges.

  8. Effect of surface deposits on electromagnetic propagation in uniform ducts

    NASA Technical Reports Server (NTRS)

    Baumeister, Kenneth J.

    1991-01-01

    A finite-element Galerkin formulation has been used to study the effect of material surface deposits on the reflective characteristics of straight uniform ducts with PEC (perfectly electric conducting) walls. Over a wide frequency range, the effect of both single and multiple dielectric surface deposits on the duct reflection coefficient were examined. The power reflection coefficient was found to be significantly increased by the addition of deposits on the wall.

  9. Oxygen concentration control of dopamine-induced high uniformity surface coating chemistry.

    PubMed

    Kim, Hyo Won; McCloskey, Bryan D; Choi, Tae Hwan; Lee, Changho; Kim, Min-Joung; Freeman, Benny D; Park, Ho Bum

    2013-01-23

    Material surface engineering has attracted great interest in important applications, including electronics, biomedicine, and membranes. More recently, dopamine has been widely exploited in solution-based chemistry to direct facile surface modification. However, unsolved questions remain about the chemical identity of the final products, their deposition kinetics and their binding mechanism. In particular, the dopamine oxidation reaction kinetics is a key to improving surface modification efficiency. Here, we demonstrate that high O(2) concentrations in the dopamine solution lead to highly homogeneous, thin layer deposition on any material surfaces via accelerated reaction kinetics, elucidated by Le Chatelier's principle toward dopamine oxidation steps in a Michael-addition reaction. As a result, highly uniform, ultra-smooth modified surfaces are achieved in much shorter deposition times. This finding provides new insights into the effect of reaction kinetics and molecular geometry on the uniformity of modifications for surface engineering techniques.

  10. Soil surface morphology evolution under spatiallynon-uniform rainfall

    NASA Astrophysics Data System (ADS)

    Cheraghi, M.; Rinaldo, A.; Sander, G. C.; Barry, D. A.

    2016-12-01

    We evaluated the applicability of a large-scale river network evolution modelused to simulate morphological changes of a laboratory-scale landscape onwhich there were no visible rills. Previously, such models were used onlyat the landscape scale, or in laboratory experiments where rills form in thesoils surface. The flume-scale experiment (1-m × 2-m surface area) was de-signed to allow model calibration. Low-cohesive fine sand was placed in theflume while the slope and relief height were 5% and 25 cm, respectively.Non-uniform rainfall with an average intensity of 85 mmh -1 and a stan-dard deviation of 26% was applied to the sediment surface for 16 h. Highresolution Digital Elevation Models were captured at intervals during theexperiment. Estimates of the overland flow drainage network were derivedand, using these, the river network evolution model was numerically solvedand calibrated. A noticeable feature of the experiment was a steep transitionzone in soil elevation that migrated upstream during the experiment. Physi-cally, this zone indicates where the shear stress is sufficient to cause sediment1erosion. The model was calibrated during the first 4 h of experiment. Af-terwards, it predicted the subsequent 12 h of measured surface morphologychanges. Therefore, the applicability of the landscape evolution model wasextended for non-uniform rainfall and in absence of visible rills.Keywords:Numerical simulation, Particle Swarm Optimization, Sediment transport,River network evolution model.

  11. Designing steep, sharp patterns on uniformly ion-bombarded surfaces

    PubMed Central

    Perkinson, Joy C.; Aziz, Michael J.; Brenner, Michael P.; Holmes-Cerfon, Miranda

    2016-01-01

    We propose and experimentally test a method to fabricate patterns of steep, sharp features on surfaces, by exploiting the nonlinear dynamics of uniformly ion-bombarded surfaces. We show via theory, simulation, and experiment that the steepest parts of the surface evolve as one-dimensional curves that move in the normal direction at constant velocity. The curves are a special solution to the nonlinear equations that arises spontaneously whenever the initial patterning on the surface contains slopes larger than a critical value; mathematically they are traveling waves (shocks) that have the special property of being undercompressive. We derive the evolution equation for the curves by considering long-wavelength perturbations to the one-dimensional traveling wave, using the unusual boundary conditions required for an undercompressive shock, and we show this equation accurately describes the evolution of shapes on surfaces, both in simulations and in experiments. Because evolving a collection of one-dimensional curves is fast, this equation gives a computationally efficient and intuitive method for solving the inverse problem of finding the initial surface so the evolution leads to a desired target pattern. We illustrate this method by solving for the initial surface that will produce a lattice of diamonds connected by steep, sharp ridges, and we experimentally demonstrate the evolution of the initial surface into the target pattern. PMID:27698147

  12. Screened Coulomb interactions with non-uniform surface charge

    NASA Astrophysics Data System (ADS)

    Ghosal, Sandip; Sherwood, John D.

    2017-03-01

    The screened Coulomb interaction between a pair of infinite parallel planes with spatially varying surface charge is considered in the limit of small electrical potentials for arbitrary Debye lengths. A simple expression for the disjoining pressure is derived in terms of a two-dimensional integral in Fourier space. The integral is evaluated for periodic and random charge distributions and the disjoining pressure is expressed as a sum over Fourier-Bloch reciprocal lattice vectors or in terms of an integral involving the autocorrelation function, respectively. The force between planes with a finite area of uniform charge, a model for the DLVO interaction between finite surfaces, is also calculated. It is shown that the overspill of the charge cloud beyond the region immediately between the charged areas results in a reduction of the disjoining pressure, as reported by us recently in the long Debye length limit for planes of finite width.

  13. A uniform, quality controlled Surface Ocean CO2 Atlas (SOCAT)

    NASA Astrophysics Data System (ADS)

    Pfeil, B.; Olsen, A.; Bakker, D. C. E.; Hankin, S.; Koyuk, H.; Kozyr, A.; Malczyk, J.; Manke, A.; Metzl, N.; Sabine, C. L.; Akl, J.; Alin, S. R.; Bates, N.; Bellerby, R. G. J.; Borges, A.; Boutin, J.; Brown, P. J.; Cai, W.-J.; Chavez, F. P.; Chen, A.; Cosca, C.; Fassbender, A. J.; Feely, R. A.; González-Dávila, M.; Goyet, C.; Hales, B.; Hardman-Mountford, N.; Heinze, C.; Hood, M.; Hoppema, M.; Hunt, C. W.; Hydes, D.; Ishii, M.; Johannessen, T.; Jones, S. D.; Key, R. M.; Körtzinger, A.; Landschützer, P.; Lauvset, S. K.; Lefèvre, N.; Lenton, A.; Lourantou, A.; Merlivat, L.; Midorikawa, T.; Mintrop, L.; Miyazaki, C.; Murata, A.; Nakadate, A.; Nakano, Y.; Nakaoka, S.; Nojiri, Y.; Omar, A. M.; Padin, X. A.; Park, G.-H.; Paterson, K.; Perez, F. F.; Pierrot, D.; Poisson, A.; Ríos, A. F.; Santana-Casiano, J. M.; Salisbury, J.; Sarma, V. V. S. S.; Schlitzer, R.; Schneider, B.; Schuster, U.; Sieger, R.; Skjelvan, I.; Steinhoff, T.; Suzuki, T.; Takahashi, T.; Tedesco, K.; Telszewski, M.; Thomas, H.; Tilbrook, B.; Tjiputra, J.; Vandemark, D.; Veness, T.; Wanninkhof, R.; Watson, A. J.; Weiss, R.; Wong, C. S.; Yoshikawa-Inoue, H.

    2013-04-01

    A well-documented, publicly available, global data set of surface ocean carbon dioxide (CO2) parameters has been called for by international groups for nearly two decades. The Surface Ocean CO2 Atlas (SOCAT) project was initiated by the international marine carbon science community in 2007 with the aim of providing a comprehensive, publicly available, regularly updated, global data set of marine surface CO2, which had been subject to quality control (QC). Many additional CO2 data, not yet made public via the Carbon Dioxide Information Analysis Center (CDIAC), were retrieved from data originators, public websites and other data centres. All data were put in a uniform format following a strict protocol. Quality control was carried out according to clearly defined criteria. Regional specialists performed the quality control, using state-of-the-art web-based tools, specially developed for accomplishing this global team effort. SOCAT version 1.5 was made public in September 2011 and holds 6.3 million quality controlled surface CO2 data points from the global oceans and coastal seas, spanning four decades (1968-2007). Three types of data products are available: individual cruise files, a merged complete data set and gridded products. With the rapid expansion of marine CO2 data collection and the importance of quantifying net global oceanic CO2 uptake and its changes, sustained data synthesis and data access are priorities.

  14. Effect of excimer laser radiant exposure on uniformity of ablated corneal surface.

    PubMed

    Fantes, F E; Waring, G O

    1989-01-01

    The argon fluoride (193 nm) excimer laser is being used to change the anterior corneal curvature for correction of refractive errors. Uniformity of the surface following laser ablation may play an important role in the rate of epithelial healing and amount and type of stromal scarring. To test the effect of radiant exposure (fluence) on surface smoothness, we ablated rabbit corneas with the 193 nm argon fluoride excimer laser at nine radiant exposures from 50 to 850 mJ/cm2. A total energy of 100 J/cm2 was used for each ablation at a frequency of 1 Hz. Scanning electron microscopy demonstrated progressive improvement of surface smoothness with increasing radiant exposures. Transmission electron microscopy demonstrated no consistent increase in thickness to the surface condensate (pseudomembrane) with increasing radiant exposure. Improvement in surface quality associated with increasing radiant exposures may result from a more uniform depth of ablation per pulse in the corneal lamellae that absorb laser wavelengths differently. Radiant exposures at levels where the depth of ablation is the same regardless of increasing energy densities achieve a more uniform surface because inhomogeneities in the beam and variation in energy from pulse to pulse do not affect the ablation rate.

  15. Nanosecond laser texturing of uniformly and non-uniformly wettable micro structured metal surfaces for enhanced boiling heat transfer

    NASA Astrophysics Data System (ADS)

    Zupančič, Matevž; Može, Matic; Gregorčič, Peter; Golobič, Iztok

    2017-03-01

    Microstructured uniformly and non-uniformly wettable surfaces were created on 25-μm-thin stainless steel foils by laser texturing using a marking nanosecond Nd:YAG laser (λ = 1064 nm) and utilizing various laser fluences and scan line separations. High-speed photography and high-speed IR thermography were used to investigate nucleate boiling heat transfer on the microstructured surfaces. The most pronounced results were obtained on a surface with non-uniform microstructure and non-uniform wettability. The obtained results show up to a 110% higher heat transfer coefficients and 20-40 times higher nucleation site densities compared to the untextured surface. We show that the number of active nucleation sites is significantly increased in the vicinity of microcavities that appeared in areas with the smallest (10 μm) scan line separation. Furthermore, this confirms the predictions of nucleation criteria and proves that straightforward, cost-effective nanosecond laser texturing allows the production of cavities with diameters of up to a few micrometers and surfaces with non-uniform wettability. Additionally, this opens up important possibilities for a more deterministic control over the complex boiling process.

  16. Layer uniformity in glucose oxidase immobilization on SiO 2 surfaces

    NASA Astrophysics Data System (ADS)

    Libertino, Sebania; Scandurra, Antonino; Aiello, Venera; Giannazzo, Filippo; Sinatra, Fulvia; Renis, Marcella; Fichera, Manuela

    2007-09-01

    The goal of this work was the characterization, step by step, of the enzyme glucose oxidase (GOx) immobilization on silicon oxide surfaces, mainly by means of X-Ray photoelectron spectroscopy (XPS). The immobilization protocol consists of four steps: oxide activation, silanization, linker molecule deposition and GOx immobilization. The linker molecule, glutaraldehyde (GA) in this study, must be able to form a uniform layer on the sample surface in order to maximize the sites available for enzyme bonding and achieve the best enzyme deposition. Using a thin SiO 2 layer grown on Si wafers and following the XPS Si2p signal of the Si substrate during the immobilization steps, we demonstrated both the glutaraldehyde layer uniformity and the possibility to use XPS to monitor thin layer uniformity. In fact, the XPS substrate signal, not shielded by the oxide, is suppressed only when a uniform layer is deposited. The enzyme correct immobilization was monitored using the XPS C1s and N1s signals. Atomic force microscopy (AFM) measurements carried out on the same samples confirmed the results.

  17. High-voltage electrode optimization towards uniform surface treatment by a pulsed volume discharge

    NASA Astrophysics Data System (ADS)

    Ponomarev, A. V.; Pedos, M. S.; Scherbinin, S. V.; Mamontov, Y. I.; Ponomarev, S. V.

    2015-11-01

    In this study, the shape and material of the high-voltage electrode of an atmospheric pressure plasma generation system were optimised. The research was performed with the goal of achieving maximum uniformity of plasma treatment of the surface of the low-voltage electrode with a diameter of 100 mm. In order to generate low-temperature plasma with the volume of roughly 1 cubic decimetre, a pulsed volume discharge was used initiated with a corona discharge. The uniformity of the plasma in the region of the low-voltage electrode was assessed using a system for measuring the distribution of discharge current density. The system's low-voltage electrode - collector - was a disc of 100 mm in diameter, the conducting surface of which was divided into 64 radially located segments of equal surface area. The current at each segment was registered by a high-speed measuring system controlled by an ARM™-based 32-bit microcontroller. To facilitate the interpretation of results obtained, a computer program was developed to visualise the results. The program provides a 3D image of the current density distribution on the surface of the low-voltage electrode. Based on the results obtained an optimum shape for a high-voltage electrode was determined. Uniformity of the distribution of discharge current density in relation to distance between electrodes was studied. It was proven that the level of non-uniformity of current density distribution depends on the size of the gap between electrodes. Experiments indicated that it is advantageous to use graphite felt VGN-6 (Russian abbreviation) as the material of the high-voltage electrode's emitting surface.

  18. Metallic nanocone array photonic substrate for high-uniformity surface deposition and optical detection of small molecules

    NASA Astrophysics Data System (ADS)

    Coppé, Jean-Philippe; Xu, Zhida; Chen, Yi; Logan Liu, G.

    2011-06-01

    Molecular probe arrays printed on solid surfaces such as DNA, peptide, and protein microarrays are widely used in chemical and biomedical applications especially genomic and proteomic studies (Pollack et al 1999 Nat. Genet. 23 41-6, Houseman et al 2002 Nat. Biotechnol. 20 270-4, Sauer et al 2005 Nat. Rev. Genet. 6 465-76) as well as surface imaging and spectroscopy (Mori et al 2008 Anal. Biochem. 375 223-31, Liu et al 2006 Nat. Nanotechnol. 1 47-52, Liu 2010 IEEE J. Sel. Top. Quantum Electron. 16 662-71). Unfortunately the printed molecular spots on solid surfaces often suffer low distribution uniformity due to the lingering 'coffee stain' (Deegan et al 1997 Nature 389 827-9) problem of molecular accumulations and blotches, especially around the edge of deposition spots caused by solvent evaporation and convection processes. Here we present, without any surface chemistry modification, a unique solid surface of high-aspect-ratio silver-coated silicon nanocone arrays that allows highly uniform molecular deposition and thus subsequent uniform optical imaging and spectroscopic molecular detection. Both fluorescent Rhodamine dye molecules and unlabeled oligopeptides are printed on the metallic nanocone photonic substrate surface as circular spot arrays. In comparison with the printed results on ordinary glass slides and silver-coated glass slides, not only high printing density but uniform molecular distribution in every deposited spot is achieved. The high-uniformity and repeatability of molecular depositions on the 'coffee stain'-free nanocone surface is confirmed by laser scanning fluorescence imaging and surface enhanced Raman imaging experiments. The physical mechanism for the uniform molecular deposition is attributed to the superhydrophobicity and localized pinned liquid-solid-air interface on the silver-coated silicon nanocone surface. The unique surface properties of the presented nanocone surface enabled high-density, high-uniformity probe spotting beneficial

  19. How Congruent Is a Strict Uniform Policy with Enhanced Academic Achievement and Self-Beliefs in Early Adolescence?

    ERIC Educational Resources Information Center

    Hoskins, Jo A.

    2014-01-01

    This study focuses on the analysis of the impact of school uniforms on student self-esteem and self-efficacy. In the past, schools have implemented school uniform policies in order to help improve student achievement as well as strengthen discipline. However, previous research has indicated an association, which is tenuous at best, with regard to…

  20. Dressed for Success? The Effect of School Uniforms on Student Achievement and Behavior. NBER Working Paper No. 17337

    ERIC Educational Resources Information Center

    Gentile, Elisabetta; Imberman, Scott A.

    2011-01-01

    Uniform use in public schools is rising, but we know little about how they affect students. Using a unique dataset from a large urban school district in the southwest United States, we assess how uniforms affect behavior, achievement and other outcomes. Each school in the district determines adoption independently, providing variation over schools…

  1. Dressed for Success? The Effect of School Uniforms on Student Achievement and Behavior. NBER Working Paper No. 17337

    ERIC Educational Resources Information Center

    Gentile, Elisabetta; Imberman, Scott A.

    2011-01-01

    Uniform use in public schools is rising, but we know little about how they affect students. Using a unique dataset from a large urban school district in the southwest United States, we assess how uniforms affect behavior, achievement and other outcomes. Each school in the district determines adoption independently, providing variation over schools…

  2. Uniform deposition of ultrathin polymer films on the surfaces of Al2O3 nanoparticles by a plasma treatment

    NASA Astrophysics Data System (ADS)

    Shi, Donglu; Wang, S. X.; van Ooij, Wim J.; Wang, L. M.; Zhao, Jiangang; Yu, Zhou

    2001-02-01

    Surface modification of nanoparticles will present great challenges due to their extremely small dimensions, high surface areas, and high surface energies. In this research, we demonstrate the uniform deposition of ultrathin polymer films of 2 nm on the surfaces of alumina nanoparticles. The deposited film can also be tailored to multilayers. Time-of-flight secondary ion mass spectroscopy was used to confirm the pyrrole thin film on the nanoparticle surfaces. Using such a nanocoating, it is possible to alter the intrinsic properties of materials that cannot be achieved by conventional methods and materials.

  3. Achieving uniform mixing in a microfluidic device: hydrodynamic focusing prior to mixing.

    PubMed

    Park, Hye Yoon; Qiu, Xiangyun; Rhoades, Elizabeth; Korlach, Jonas; Kwok, Lisa W; Zipfel, Warren R; Webb, Watt W; Pollack, Lois

    2006-07-01

    We describe a microfluidic mixer that is well-suited for kinetic studies of macromolecular conformational change under a broad range of experimental conditions. The mixer exploits hydrodynamic focusing to create a thin jet containing the macromolecules of interest. Kinetic reactions are triggered by molecular diffusion into the jet from adjacent flow layers. The ultimate time resolution of these devices can be restricted by premature contact between co-flowing solutions during the focusing process. Here, we describe the design and characterization of a mixer in which hydrodynamic focusing is decoupled from the diffusion of reactants, so that the focusing region is free from undesirable contact between the reactants. Uniform mixing on the microsecond time scale is demonstrated using a device fabricated by imprinting optical-grade plastic. Device characterization is carried out using fluorescence correlation spectroscopy (FCS) and two-photon microscopy to measure flow speeds and to quantify diffusive mixing by monitoring the collisional fluorescence quenching, respectively. Criteria for achieving microsecond time resolution are described and modeled.

  4. Uniform surface growth of copper oxide nanowires in radiofrequency plasma discharge and limiting factors

    SciTech Connect

    Filipič, Gregor; Mozetič, Miran; Cvelbar, Uroš; Baranov, Oleg; Ostrikov, Kostya

    2014-11-15

    The uniform growth of copper oxide nanowires on the top of copper plate has been investigated during the exposure to radiofrequency plasma discharge in respect to plasma properties and its localization. The copper samples of 10 mm radius and 1 mm in thickness were exposed to argon-oxygen plasma created at discharge power of 150 W. After 10 min, almost uniform growth of nanowires was achieved over large surface. There were significant distortions in nanowire length and shape near the edges. Based on the experimental results, we developed a theoretical model, which took into account a balance in heat released at the flow of the current to the nanowire and rejected from the nanowire. This model established a dependence of the maximal length of the nanowire at dependence on the plasma parameters, where the limiting factor for nanowire growth and distortions in distribution are ballistic effects of ions and their local fluxes. In contrast, the plasma heating by potential interactions of species has very little influence on the length and smaller deviations in flux are allowed for uniformity of growth.

  5. Achieving Uniform Monolayer Transition Metal Dichalcogenides Film on Silicon Wafer via Silanization Treatment: A Typical Study on WS2.

    PubMed

    Chen, Ying; Gan, Lin; Li, Huiqiao; Ma, Ying; Zhai, Tianyou

    2017-02-01

    A silanization reaction is employed to improve the dispersion of precursors on a silicon wafer for a large-size uniform transition metal dichalcogenide (TMD) film synthesis and to achieve a highly crystalline monolayer WS2 film up to 1 cm(2) . The novel strategy is also verified for the synthesis of WSe2 and MoS2 uniform films, suggesting universality for TMD film fabrication.

  6. High direct drive illumination uniformity achieved by multi-parameter optimization approach: a case study of Shenguang III laser facility.

    PubMed

    Tian, Chao; Chen, Jia; Zhang, Bo; Shan, Lianqiang; Zhou, Weimin; Liu, Dongxiao; Bi, Bi; Zhang, Feng; Wang, Weiwu; Zhang, Baohan; Gu, Yuqiu

    2015-05-04

    The uniformity of the compression driver is of fundamental importance for inertial confinement fusion (ICF). In this paper, the illumination uniformity on a spherical capsule during the initial imprinting phase directly driven by laser beams has been considered. We aim to explore methods to achieve high direct drive illumination uniformity on laser facilities designed for indirect drive ICF. There are many parameters that would affect the irradiation uniformity, such as Polar Direct Drive displacement quantity, capsule radius, laser spot size and intensity distribution within a laser beam. A novel approach to reduce the root mean square illumination non-uniformity based on multi-parameter optimizing approach (particle swarm optimization) is proposed, which enables us to obtain a set of optimal parameters over a large parameter space. Finally, this method is applied to improve the direct drive illumination uniformity provided by Shenguang III laser facility and the illumination non-uniformity is reduced from 5.62% to 0.23% for perfectly balanced beams. Moreover, beam errors (power imbalance and pointing error) are taken into account to provide a more practical solution and results show that this multi-parameter optimization approach is effective.

  7. Gold-film coating assisted femtosecond laser fabrication of large-area, uniform periodic surface structures.

    PubMed

    Feng, Pin; Jiang, Lan; Li, Xin; Rong, Wenlong; Zhang, Kaihu; Cao, Qiang

    2015-02-20

    A simple, repeatable approach is proposed to fabricate large-area, uniform periodic surface structures by a femtosecond laser. 20 nm gold films are coated on semiconductor surfaces on which large-area, uniform structures are fabricated. In the case study of silicon, cross-links and broken structures of laser induced periodic surface structures (LIPSSs) are significantly reduced on Au-coated silicon. The good consistency between the scanning lines facilitates the formation of large-area, uniform LIPSSs. The diffusion of hot electrons in the Au films increases the interfacial carrier densities, which significantly enhances interfacial electron-phonon coupling. High and uniform electron density suppresses the influence of defects on the silicon and further makes the coupling field more uniform and thus reduces the impact of laser energy fluctuations, which homogenizes and stabilizes large-area LIPSSs.

  8. High-level correlated approach to the jellium surface energy, without uniform-gas input.

    PubMed

    Constantin, Lucian A; Pitarke, J M; Dobson, J F; Garcia-Lekue, A; Perdew, John P

    2008-01-25

    We resolve the long-standing controversy over the metal surface energy: Density-functional methods that require uniform-electron-gas input agree with each other, but not with high-level correlated calculations such as Fermi hypernetted chain and diffusion Monte Carlo calculations that predict the uniform-gas correlation energy. Here we apply the inhomogeneous Singwi-Tosi-Land-Sjölander method, and find that the density functionals are indeed reliable (because the surface energy is bulklike). Our work also vindicates the use of uniform-gas-based nonlocal kernels in time-dependent density-functional theory.

  9. AN AUTOMATED SYSTEM FOR PRODUCING UNIFORM SURFACE DEPOSITS OF DRY PARTICLES

    EPA Science Inventory

    A laboratory system has been constructed that uniformly deposits dry particles onto any type of test surface. Devised as a quality assurance tool for the purpose of evaluating surface sampling methods for lead, it also may be used to generate test surfaces for any contaminant ...

  10. AN AUTOMATED SYSTEM FOR PRODUCING UNIFORM SURFACE DEPOSITS OF DRY PARTICLES

    EPA Science Inventory

    A laboratory system has been constructed that uniformly deposits dry particles onto any type of test surface. Devised as a quality assurance tool for the purpose of evaluating surface sampling methods for lead, it also may be used to generate test surfaces for any contaminant ...

  11. Patterned growth of carbon nanotubes over vertically aligned silicon nanowire bundles for achieving uniform field emission.

    PubMed

    Hung, Yung-Jr; Huang, Yung-Jui; Chang, Hsuan-Chen; Lee, Kuei-Yi; Lee, San-Liang

    2014-01-01

    A fabrication strategy is proposed to enable precise coverage of as-grown carbon nanotube (CNT) mats atop vertically aligned silicon nanowire (VA-SiNW) bundles in order to realize a uniform bundle array of CNT-SiNW heterojunctions over a large sample area. No obvious electrical degradation of as-fabricated SiNWs is observed according to the measured current-voltage characteristic of a two-terminal single-nanowire device. Bundle arrangement of CNT-SiNW heterojunctions is optimized to relax the electrostatic screening effect and to maximize the field enhancement factor. As a result, superior field emission performance and relatively stable emission current over 12 h is obtained. A bright and uniform fluorescent radiation is observed from CNT-SiNW-based field emitters regardless of its bundle periodicity, verifying the existence of high-density and efficient field emitters on the proposed CNT-SiNW bundle arrays.

  12. Uniform-sized silicone oil microemulsions: preparation, investigation of stability and deposition on hair surface.

    PubMed

    Nazir, Habiba; Lv, Piping; Wang, Lianyan; Lian, Guoping; Zhu, Shiping; Ma, Guanghui

    2011-12-01

    Emulsions are commonly used in foods, pharmaceuticals and home-personal-care products. For emulsion based products, it is highly desirable to control the droplet size distribution to improve storage stability, appearance and in-use property. We report preparation of uniform-sized silicone oil microemulsions with different droplets diameters (1.4-40.0 μm) using SPG membrane emulsification technique. These microemulsions were then added into model shampoos and conditioners to investigate the effects of size, uniformity, and storage stability on silicone oil deposition on hair surface. We observed much improved storage stability of uniform-sized microemulsions when the droplets diameter was ≤22.7 μm. The uniform-sized microemulsion of 40.0 μm was less stable but still more stable than non-uniform sized microemulsions prepared by conventional homogenizer. The results clearly indicated that uniform-sized droplets enhanced the deposition of silicone oil on hair and deposition increased with decreasing droplet size. Hair switches washed with small uniform-sized droplets had lower values of coefficient of friction compared with those washed with larger uniform and non-uniform droplets. Moreover the addition of alginate thickener in the shampoos and conditioners further enhanced the deposition of silicone oil on hair. The good correlation between silicone oil droplets stability, deposition on hair and resultant friction of hair support that droplet size and uniformity are important factors for controlling the stability and deposition property of emulsion based products such as shampoo and conditioner. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. A Uniform GTD Analysis of the Scattering of Electromagnetic Waves by a Smooth Convex Surface.

    DTIC Science & Technology

    1979-04-01

    optical electromagnetic field, an arbitrary convex surface, and a near zone field point (for which the field point may be sev- eral wavelengths from...of an arbitrary ray optical electromagnetic field by an edge in an otherwise smooth surface. Let P SB denote a field point on SB. The continuity of...surface when it is excited by a ray optical electromagnetic field. This asymptotic solution is uniform in the sense that it is valid within the

  14. A uniform geostationary visible calibration approach to achieve a climate quality dataset

    NASA Astrophysics Data System (ADS)

    Haney, C.; Doelling, D.; Bhatt, R.; Scarino, B. R.; Gopalan, A.

    2013-12-01

    The geostationary (GEO) weather satellite visible and IR image record has surpassed 30 years. They have been preserved in the ISCCP-B1U 3-hourly dataset and other archives such as McIDAS, EUMETSAT, and NOAA CLASS. Since they were designed to aid in weather forecasting, long-term calibration stability was not a high priority. All GEO imagers lack onboard visible calibration and suffer from optical degradation after they are launched. In order to piece together the 35+ GEO satellite record both in time and space, a uniform calibration approach is desired to remove individual GEO temporal trends, as well as GEO spectral band differences. Otherwise, any artificial discontinuities caused by sequential GEO satellite records or spurious temporal trends caused by optical degradation may be interpreted as a change in climate. The approach relies on multiple independent methods to reduce the overall uncertainty of the GEO calibration coefficients. Consistency among methods validates the approach. During the MODIS record (2000 to the present) the GEO satellites are inter-calibrated against MODIS using ray-matched or bore-sighted radiance pairs. The MODIS and the VIIRS follow on instruments are equipped with onboard calibration thereby providing a stable calibration reference. The GEO spectral band differences are accounted for using a Spectral Band Adjustment Factor (SBAF) based on hyper-spectral SCIAMACHY data. During the pre-MODIS era, invariant earth targets of deserts and deep convective clouds (DCC) are used. Since GEO imagers have maintained their imaging scan schedules, GEO desert and DCC bidirectional reflectance distribution functions (BRDF) can be constructed and validated during the MODIS era. The BRDF models can then be applied to historical GEO imagers. Consistency among desert and DCC GEO calibration gains validates the approach. This approach has been applied to the GEO record beginning in 1985 and the results will be presented at the meeting.

  15. Accelerated Escherichia coli inactivation in the dark on uniform copper flexible surfaces.

    PubMed

    Rtimi, Sami; Sanjines, Rosendo; Bensimon, Michël; Pulgarin, César; Kiwi, John

    2014-06-01

    The bacterial inactivation of Escherichia coli on Cu/CuO-polyester surfaces prepared by direct current magnetron sputtering was investigated in the dark and under actinic light (360 nm≤ λ ≤ 720 nm; 4.1 mW/cm(2)) as used commonly in hospital facilities. In the dark, complete bacterial inactivation (6log10 reduction) was observed within 150 min and under actinic light within 45 min. Sputtered samples led to nanoparticulate uniform Cu/CuO films ~70 nm thick. The deposition rate used was 2.2×10(15) atoms/cm(2) s as determined by profilometry. X-ray fluorescence was used to determine the sample Cu-content and transmission electron microscopy determined Cu-particles ~20 ± 5 nm in size. The film optical absorption was observed to increase with Cu-content of the sample by diffuse reflection spectroscopy. The bacterial inactivation involved redox processes between Cu/CuO-polyester and the bacteria as observed by x-ray photoelectron spectroscopy. During sample recycling, the amount of Cu-release was determined by inductively coupled plasma-mass spectroscopy. The values required for E. coli inactivation were below the cytotoxicity level threshold allowed for mammalian cells. The E. coli inactivation by Cu/CuO-polyester seems to involve an oligodynamic effect since bacterial inactivation was achieved at very low Cu-concentrations.

  16. Highlighting non-uniform temperatures close to liquid/solid surfaces

    NASA Astrophysics Data System (ADS)

    Noirez, L.; Baroni, P.; Bardeau, J. F.

    2017-05-01

    The present experimental measurements reveal that similar to external fields such as electric, magnetic, or flow fields, the vicinity of a solid surface can preclude the liquid molecules from relaxing to equilibrium, generating located non-uniform temperatures. The non-uniform temperature zone extends up to several millimeters within the liquid with a lower temperature near the solid wall (reaching ΔT = -0.15 °C ± 0.02 °C in the case of liquid water) counterbalanced at larger distances by a temperature rise. These effects highlighted by two independent methods (thermistor measurement and infra-red emissivity) are particularly pronounced for highly wetting surfaces. The scale over which non-uniform temperatures are extended indicates that the effect is assisted by intermolecular interactions, in agreement with recent developments showing that liquids possess finite shear elasticity and theoretical approaches integrating long range correlations.

  17. Non-Uniform Field Breakdown and Surface Flashover in Liquid Nitrogen Gaps for HTS Applications

    SciTech Connect

    James, David Randy; Sauers, Isidor; Tuncer, Enis; Ellis, Alvin R; Tekletsadik, Kasegn; Hazelton, Drew

    2006-01-01

    Abstract: Liquid nitrogen (LN2) is used as a coolant and electrical insulation in many High Temperature Superconducting (HTS) applications. Hence a good understanding of the breakdown characteristics of this medium under a variety of practical electrode geometries and conditions is needed for design of high voltage equipment. While there is considerable literature on breakdown of LN2 gaps for uniform (plane-plane) or quasi-uniform electric fields (sphere-plane), there is much less data available for highly non-uniform field gaps and for surface flashover along insulators. In this paper we present results on sphere-plane and cylindrical rod-plane gaps in LN2 as a function of sphere and rod diameters and radius of the rod edge at 1 bar pressure. In addition the surface flashover voltages of Fiber-Reinforced Plastic (FRP) in LN2 with these electrode arrangements will also be reported.

  18. Thin Films of Uniform Hematite Nanoparticles: Controls on Surface Hydrophobicity and Self-Assembly

    SciTech Connect

    Wang, Wei; Liang, Liyuan; Johs, Alexander; Gu, Baohua

    2008-01-01

    In this study we show that uniform hematite ( -Fe2O3) nanoparticle thin films with controlled layer thickness can be formed by Langmuir-Blodgett (LB) monolayer deposition on surface areas of several square centimeters. The technique involves synthesis of uniform hematite nanoparticles by forced hydrolysis and surface modifications for increased hydrophobicity to bring the particles to the air-water interface. Methods of thermal treatment, stepped solvent exchange, and oleate surfactant coating were studied for their effectiveness in increasing hydrophobicity by removing surface adsorbed water and OH groups and were subsequently validated by Fourier-transform infrared (FTIR) spectral analysis. Surface pressure-area ( -A) and surface pressure-time ( -t) isotherms indicate that the stability of the particle monolayer at the air-water interface depends on the method of surface modification. Thermal evaporation treatment was found to produce thin films of hematite nanoparticles with the greatest uniformity and surface coverage as characterized by UV-visible spectroscopic, scanning electron microscopic (SEM) and atomic force microscopic (AFM) analyses.

  19. Uniform, large surface-area polarization by modifying corona-electrodes geometry.

    PubMed

    Tansel, T; Ener Rusen, S; Rusen, A

    2013-01-01

    We report on the uniform, large scale polarization of ferroelectric materials by a newly designed corona charging technique developing nonconventional electrodes geometry. The results of pyroelectric measurements represented the spatial homogeneity of the polarization attained through a surface area of ~25 cm(2).

  20. Highly uniform and reproducible vertical-cavity surface emitting lasers grown by metalorganic chemical vapor deposition

    SciTech Connect

    Hou, H.Q.; Chui, H.C.; Choquette, K.D.; Hammons, B.E.; Breiland, W.G.; Geib, K.M.

    1996-01-01

    We show that the uniformity of the lasing wavelength of vertical-cavity surface emitting lasers (VCSELs) can be as good as {plus_minus}0.3% across a entire 3 in. wafer in MOCVD growth with a similar run-to-run reproducibility.

  1. Algebraic grid adaptation method using non-uniform rational B-spline surface modeling

    NASA Technical Reports Server (NTRS)

    Yang, Jiann-Cherng; Soni, B. K.

    1992-01-01

    An algebraic adaptive grid system based on equidistribution law and utilized by the Non-Uniform Rational B-Spline (NURBS) surface for redistribution is presented. A weight function, utilizing a properly weighted boolean sum of various flow field characteristics is developed. Computational examples are presented to demonstrate the success of this technique.

  2. Effect of surface deposits on electromagnetic waves propagating in uniform ducts

    NASA Technical Reports Server (NTRS)

    Baumeister, Kenneth J.

    1990-01-01

    A finite-element Galerkin formulation was used to study the effect of material surface deposits on the reflective characteristics of straight uniform ducts with PEC (perfectly electric conducting) walls. Over a wide frequency range, the effect of both single and multiple surface deposits on the duct reflection coefficient were examined. The power reflection coefficient was found to be significantly increased by the addition of deposits on the wall.

  3. A technique to achieve uniform stress distribution in compressive creep testing of advanced ceramics at high temperatures

    SciTech Connect

    Liu, K.C.; Stevens, C.O.; Brinkman, C.R.; Holshauser, N.E.

    1996-05-01

    A technique to achieve stable and uniform uniaxial compression is offered for creep testing of advanced ceramic materials at elevated temperatures, using an innovative self-aligning load-train assembly. Excellent load-train alignment is attributed to the inherent ability of a unique hydraulic universal coupler to maintain self-aligning. Details of key elements, design concept, and pricniples of operation of the self-aligning coupler are described. A method of alignment verification using a strain-gaged specimen is then discussed. Results of verification tests indicate that bending below 1.5% is routinely achievable usin the load-train system. A successful compression creep test is demonstrated using a dumbbell-shpaed Si nitride specimen tested at 1300 C for over 4000 h.

  4. A scheme for coupling land surface processes using mutliple non-uniform grid scales

    NASA Astrophysics Data System (ADS)

    Miller, N. L.; Bastidas, L. A.; Yatheendradas, Y.; Jin, J.; Sorooshian, S.

    2003-04-01

    Land surface processes respond differently at a range of scales, depending on the sensitivity and the available information for characterizing the parameter space. A multi-scale procedure for coupling a Land Surface Model (LSM) with atmospheric and subsurface processes has been developed. The Non-uniform Grid Scheme (NGS) utilizes hierarchical sub-grids with a high degree of characterization, that are nested within grid-matched coarser grids preserving spatial location. Conservation of mass and momentum is maintained across the grids and aggregated fluxes are computed for the larger scale, which will bi-directionally coupled to a fine-scale regional atmospheric model. Initial studies have shown a shift in the latent and sensible heating rates as the degree of land surface heterogeneity is increased. The Non-uniform Grid Scheme was setup for the NCEP Noah LSM over the San Pedro River Basin in Arizona as a sensitivity study. An analysis using the Noah LSM, in offline fashion, driven with outputs from the NCAR Mesoscale Model (MM5) is presented. Initially, uniform grids with 1, 4, and 9 km resolution are used throughout the domain. This is followed by a multiple resolution grid structure defined by the degree of land surface and sub-surface characteristics of the San Pedro Basin. The influence of the parameter values is also assessed using the default values for semi-arid conditions (uniform for the entire domain) as a benchmark. Grid-dependent non-uniform parameterization is based on a multi-criteria approach using the MOCOM-UA optimization algorithm. Parameter values derived from remote sensing, and values obtained from a combination of remote sensing and parameter optimization techniques are also presented.

  5. Low temperature atmospheric microplasma jet array for uniform treatment of polymer surface for flexible electronics

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Wang, Xiaolin; Yang, Bin; Chen, Xiang; Yang, Chunsheng; Liu, Jingquan

    2017-07-01

    In this paper, the uniformity of polymer film etching by an atmospheric pressure He/O2 microplasma jet array (μPJA) is first investigated with different applied voltage. Plasma characteristics of μPJA were recorded by optical discharge images. Morphologies and chemical compositions of polymer film etched by μPJA were analyzed by optical microscopy, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS). By increasing the applied voltage from 8.5 kV to 16.4 kV, the non-uniformity of the luminous intensity of the plasma jets increases. It is interesting that the plasma treated regions are actually composed of an etched region and modification region, with distinct morphologies and chemical compositions. The diameters of the etched parylene-C film show the increase of non-uniformity with higher applied voltage. SEM results show that the non-uniformity of surface morphologies of both the modification regions and etched regions increases with the increase of applied voltage. EDS and XPS results also present the significant effect of higher applied voltage on the non-uniformity of surface chemical compositions of both modification and etched regions. The Coulomb interaction of the streamer heads and the hydrodynamic interaction between the plasma jets and the surrounding air are considered to be responsible for this phenomenon. The results shown in this work can help improve the processing quality of polymer film etched by an atmospheric pressure microplasma jet array and two applications are demonstrated to illustrate the uniform downstream surface treatment.

  6. Effect of non-uniform surface resistance on the quality factor of superconducting niobium cavity

    NASA Astrophysics Data System (ADS)

    Tan, Weiwei; Lu, Xiangyang; Yang, Ziqin; Zhao, Jifei; Yang, Deyu; Yang, Yujia

    2016-08-01

    The formula Rs = G /Q0 is commonly used in the calculation of the surface resistance of radio frequency niobium superconducting cavities. The applying of such equation is under the assumption that surface resistance is consistent over the cavity. However, the distribution of the magnetic field varies over the cavity. The magnetic field in the equator is much higher than that in the iris. According to Thermal Feedback Theory, it leads non-uniform distribution of the density of heat flux, which results in a different temperature distribution along the cavity inter surface. The BCS surface resistance, which depends largely on the temperature, is different in each local inner surface. In this paper, the effect of surface non-uniform resistance on the quality factor has been studied, through the calculation of Q0 in the original definition of it. The results show that it is necessary to consider the non-uniform distribution of magnetic field when the accelerating field is above 20 MV/m for TESLA cavities. Also, the effect of inhomogeneity of residual resistance on the quality factor is discussed. Its distribution barely affects the quality factor.

  7. Self-organization of uniform Ag nano-clusters on Sb-terminated Si(100) surface

    NASA Astrophysics Data System (ADS)

    Park, Kang-Ho; Ha, Jeong Sook; Yun, Wan Soo; Lee, El-Hang

    1998-10-01

    Nanometer sized Ag clusters were found to be uniformly formed in the initial stage of Ag growth on Sb-terminated Si(100) surfaces. Due to the saturation of Si dangling bonds by Sb adatoms, Ag clusters were grown on the Sb-terminated Si(100) surface without a Ag wetting layer. We found that the diameters and heights of Ag clusters were confined to a nanometer scale, and the size distribution was quite uniform compared to Ag growth on Sb-terminated Si(111). Those features are considered to result from the separation of Ag clusters by coherently aligned voids in the underlying Sb-terminated Si(100) surface. Tunneling spectroscopy measurements showed that the local conduction properties of Ag clusters gradually changed from semiconducting to metallic as Ag coverage increased.

  8. Uniform coating of high aspect ratio surfaces through atomic layer deposition

    NASA Astrophysics Data System (ADS)

    Nolan, Mark; Povey, Ian; Elliot, Simon; Cordero, Nicolas; Pemble, Martyn; Shortt, Brian; Bavdaz, Marcos

    2012-09-01

    Innovative X-ray ray imaging optic technologies, Silicon Pore Optics for example, are often characterised by large length to pore diameter aspect ratios. Such ratios present challenges to the deposition of reflectivity enhancing metallic coatings onto the mirror substrate surfaces. The technique of Atomic Layer Deposition (ALD) is perfectly suited to addressing this challenge due to the inherent self-limiting nature of the process which yields highly uniform coatings with surface roughness compatible with the requirements of high resolution X-ray imaging. We describe the results of a project aimed at developing an optimised ALD reactor and process to coat the internal wall surfaces of high aspect ratio samples with a uniform and smooth metallic layer. For sample substrates of aspect ratio ~100 the reactor has realised an average gradient of 1nm in the thickness of an Al2O3 coating on the internal walls of a 76 mm long glass tube.

  9. Uniform Dust Distributor for Testing Radiative Emittance of Dust-Coated Surfaces

    NASA Technical Reports Server (NTRS)

    Hurlbert, Kathryn Miller; Witte, Larry C.; Hollingsworth, D. Keith

    2012-01-01

    This apparatus distributes dust (typical of the Martian surface) in a uniform fashion on the surface of multiple samples simultaneously. The primary innovation is that the amount of dust deposited on the multiple surfaces can be controlled by the time that the apparatus operates, and each sample will be subject to the same amount of dust deposition. The exact weight of dust that is added per unit of sample area is determined by the use of slides that can be removed sequentially after each dusting.

  10. Integrating uniform design and response surface methodology to optimize thiacloprid suspension

    PubMed Central

    Li, Bei-xing; Wang, Wei-chang; Zhang, Xian-peng; Zhang, Da-xia; Mu, Wei; Liu, Feng

    2017-01-01

    A model 25% suspension concentrate (SC) of thiacloprid was adopted to evaluate an integrative approach of uniform design and response surface methodology. Tersperse2700, PE1601, xanthan gum and veegum were the four experimental factors, and the aqueous separation ratio and viscosity were the two dependent variables. Linear and quadratic polynomial models of stepwise regression and partial least squares were adopted to test the fit of the experimental data. Verification tests revealed satisfactory agreement between the experimental and predicted data. The measured values for the aqueous separation ratio and viscosity were 3.45% and 278.8 mPa·s, respectively, and the relative errors of the predicted values were 9.57% and 2.65%, respectively (prepared under the proposed conditions). Comprehensive benefits could also be obtained by appropriately adjusting the amount of certain adjuvants based on practical requirements. Integrating uniform design and response surface methodology is an effective strategy for optimizing SC formulas. PMID:28383036

  11. Integrating uniform design and response surface methodology to optimize thiacloprid suspension.

    PubMed

    Li, Bei-Xing; Wang, Wei-Chang; Zhang, Xian-Peng; Zhang, Da-Xia; Mu, Wei; Liu, Feng

    2017-04-06

    A model 25% suspension concentrate (SC) of thiacloprid was adopted to evaluate an integrative approach of uniform design and response surface methodology. Tersperse2700, PE1601, xanthan gum and veegum were the four experimental factors, and the aqueous separation ratio and viscosity were the two dependent variables. Linear and quadratic polynomial models of stepwise regression and partial least squares were adopted to test the fit of the experimental data. Verification tests revealed satisfactory agreement between the experimental and predicted data. The measured values for the aqueous separation ratio and viscosity were 3.45% and 278.8 mPa·s, respectively, and the relative errors of the predicted values were 9.57% and 2.65%, respectively (prepared under the proposed conditions). Comprehensive benefits could also be obtained by appropriately adjusting the amount of certain adjuvants based on practical requirements. Integrating uniform design and response surface methodology is an effective strategy for optimizing SC formulas.

  12. Boundary Layer Flow Control with a One Atmosphere Uniform Glow Discharge Surface Plasma

    NASA Technical Reports Server (NTRS)

    Roth, J. Reece; Sherman, Daniel M.; Wilkinson, Stephen P.

    1998-01-01

    Low speed wind tunnel data have been acquired for planar panels covered by a uniform, glow-discharge surface plasma in atmospheric pressure air known as the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP). Streamwise and spanwise arrays of flush, plasma-generating surface electrodes have been studied in laminar, transitional, and fully turbulent boundary layer flow. Plasma between symmetric streamwise electrode strips caused large increases in panel drag, whereas asymmetric spanwise electrode configurations produced a significant thrust. Smoke wire flow visualization and mean velocity diagnostics show the primary cause of the phenomena to be a combination of mass transport and vortical structures induced by strong paraelectric ElectroHydroDynamic (EHD) body forces on the flow.

  13. Myrtle Beach AFB South Carolina. Revised Uniform Summary of Surface Weather Observations. Parts A-F

    DTIC Science & Technology

    1975-07-03

    service for each period are as follows: Air Force Stations: UI. S. Navy and National Weather Service (USWB)I-Beginning thru 1945 at 0800IST Beginning...ADA 0 74658 USAFETAC/DS-79/032 DATA PROCESSING BRANCH USAFETAC Air Weather Service ( MAC) REVISED UNIFORM SUMMARY OF SURFACE WEATHER OBSERVATIQIG...or by DDC to the Naticnal Technical Information Service (NTIS). This technical report has been reviewed and is approved for publication. $CARL A. BOWER

  14. Academic Achievement, Intelligence, and Creativity: A Regression Surface Analysis.

    PubMed

    Marjoribanks, K

    1976-01-01

    Data collected on 400 12-year-old English school children were used to examine relations between measures of intelligence, creativity and academic achievement. Complex multiple regression models, which included terms to account for the possible interaction and curvilinear relations between intelligence, creativity and academic achievement were used to construct regression surfaces. The surfaces showed that the traditional threshold hypothesis, which suggests that beyond a certain level of intelligence academic achievement is related increasingly to creativity and ceases to be related strongly to intelligence, was not supported. For some areas of academic performance the results suggest an alternate proposition, that creativity ceases to be related to achievement after a threshold level of intelligence has been reached. It was also found that at high levels of verbal ability, non-verbal ability and creativity appeared to have differential relations with academic achievement.

  15. Free-surface flow of liquid oxygen under non-uniform magnetic field

    NASA Astrophysics Data System (ADS)

    Bao, Shi-Ran; Zhang, Rui-Ping; Wang, Kai; Zhi, Xiao-Qin; Qiu, Li-Min

    2017-01-01

    The paramagnetic property of oxygen makes it possible to control the two-phase flow at cryogenic temperatures by non-uniform magnetic fields. The free-surface flow of vapor-liquid oxygen in a rectangular channel was numerically studied using the two-dimensional phase field method. The effects of magnetic flux density and inlet velocity on the interface deformation, flow pattern and pressure drop were systematically revealed. The liquid level near the high-magnetic channel center was lifted upward by the inhomogeneous magnetic field. The interface height difference increased almost linearly with the magnetic force. For all inlet velocities, pressure drop under 0.25 T was reduced by 7-9% due to the expanded local cross-sectional area, compared to that without magnetic field. This work demonstrates the effectiveness of employing non-uniform magnetic field to control the free-surface flow of liquid oxygen. This non-contact method may be used for promoting the interface renewal, reducing the flow resistance, and improving the flow uniformity in the cryogenic distillation column, which may provide a potential for enhancing the operating efficiency of cryogenic air separation.

  16. Double freeform surfaces lens design for LED uniform illumination with high distance-height ratio

    NASA Astrophysics Data System (ADS)

    Wu, Heng; Zhang, Xianmin; Ge, Peng

    2015-10-01

    A practical method is proposed to design a double freeform surfaces (DFS) lens for LED sources, in order to form uniform illumination in the high distance-height ratio (DHR) lighting system. The ray mapping relationship is first established between the solid angle of the source and the target plane according to the energy conservation law and the variable separation method. A DFS lens is then constructed simultaneously and point by point to the ray mapping based on the Snell's law. Optical performance of the lens is investigated by the Monte Carlo method. A simple and effective method is utilized to optimize the lens design in accordance with the simulation results. As an example, a DFS lens with DHR of 2.5 (distance 30 mm, height 12 mm) is designed by the proposed method. Compared with the traditional methods, the illuminance uniformity is significantly improved from 67.20% to 86.43% and the size of the lens is dramatically reduced.

  17. Surface-emitting, distributed-feedback diode lasers with uniform near-field intensity profile

    NASA Astrophysics Data System (ADS)

    Lopez, James; Kasraian, Masoud; Botez, Dan

    1998-10-01

    Theoretical analysis of second-order surface-emitting, complex-coupled distributed feedback diode lasers with first-order distributed Bragg reflectors (DBR) is presented. The DBR reflectors are shown to insure simultaneous operation in a virtually uniform near-field profile with high efficiency and adequate intermodal discrimination. Such devices display symmetric-mode (single-lobe) surface emission with relatively high external differential quantum efficiency (30%), low gain threshold (18 cm-1), and <8% near-field intensity profile variations (in the longitudinal direction). The devices have the potential to provide >100 mW of stable, single-mode cw power, significantly higher than it is possible with vertical-cavity surface-emitting lasers. It is also shown that the device studied here can be combined with a resonant optical waveguide array device to produce a 2D uniform near-field surface-emitting source capable of providing greater than 1 W cw power in a stable, single-lobed beam.

  18. Reflection of an acoustic line source by an impedance surface with uniform flow

    NASA Astrophysics Data System (ADS)

    Brambley, E. J.; Gabard, G.

    2014-10-01

    An exact analytic solution is derived for the 2D acoustic pressure field generated by a time-harmonic line mass source located above an impedance surface with uniform grazing flow. Closed-form asymptotic solutions in the far field are also provided. The analysis is valid for both locally-reacting and nonlocally-reacting impedances, as is demonstrated by analyzing a nonlocally reacting effective impedance representing the presence of a thin boundary layer over the surface. The analytic solution may be written in a form suggesting a generalization of the method of images to account for the impedance surface. The line source is found to excite surface waves on the impedance surface, some of which may be leaky waves which contradict the assumption of decay away from the surface predicted in previous analyses of surface waves with flow. The surface waves may be treated either (correctly) as unstable waves or (artificially) as stable waves, enabling comparison with previous numerical or mathematical studies which make either of these assumptions. The computer code for evaluating the analytic solution and far-field asymptotics is provided in the supplementary material. It is hoped this work will provide a useful benchmark solution for validating 2D numerical acoustic codes.

  19. XPS analysis of lithium surface and modification of surface state for uniform deposition of lithium

    SciTech Connect

    Kanamura, K.; Shiraishi, S.; Takehara, Z.

    1995-12-31

    The surface modification of lithium deposited at various current densities in propylene carbonate containing 1.0 ml dm{sup {minus}3} LiClO{sub 4} was performed by addition of various amounts of HF into the electrolyte, in order to investigate the effect of the HF addition on the surface reaction of lithium. XPS and SEM analyses showed that the surface state of lithium was influenced by the concentration of HF and the electrodeposition current. These two parameters are related to the chemical reaction rate of the lithium surface with HF and the electrodeposition rate of lithium, respectively. The surface modification was highly effective in suppressing lithium dendrite formation when the chemical reaction rate with HF was greater than the electrochemical deposition rate of lithium.

  20. Atlas of relectance patterns for uniform earth and cloud surfaces (NIMBUS-7ERB-61 days)

    NASA Astrophysics Data System (ADS)

    Taylor, V. R.; Stowe, L. L.

    1984-07-01

    Scanning channel data of the Nimbus-7 ERB instrument have been combined with auxiliary information to describe the radiative characteristics of surfaces as observed through the atmosphere. This information has been recorded on the ERB 'Sub-Target Radiance Tapes' (STRT). A description of that data base and procedures for obtaining the data may be found in Stowe and Fromm (1983). Selected data from the STRTs have been sorted into eight uniform earth and cloud surface types. Diagrams illustrating the bi-directional reflectivity of these surfaces have been constructed. The observed dependence of albedo on solar zenith angle (SZA) is discussed and figures illustrating this dependence are given. An extensive list of references is also given. This report contains a complete set of reflectance diagrams (patterns) and tables listing the values that were used in their construction and interpretation.

  1. An instrument for the heat flux measurement from a contour of a surface with uniform temperature

    NASA Astrophysics Data System (ADS)

    Baughn, J. W.; Hoffman, M. A.; Lee, Daehee

    1994-03-01

    An instrument for the measurement of the heat flux distribution along an internal or external contour of a surface with a uniform temperature is described. The main element in this instrument is an electrically heated narrow nickel/chromium ribbon which is mounted flush with, but thermally and electrically insulated from, walls on all sides. The walls are separately heated and are made of a highly conducting material (e.g., aluminum) to ensure a uniform temperature. Differential thermocouples are used to measure the temperature difference between the walls and Ni/Cr ribbon at various positions along the ribbon. The ribbon power is adjusted until the differential temperature is nulled at a particular position on the ribbon. Since conduction along the ribbon is small, the electrical power divided by the sensor area is a direct measure of the surface heat flux at the nulled position. This makes it possible to measure the local time-average heat flux at various positions along a contour of a surface inside a circular duct. The time constant in this application was 13 s. An uncertainty analysis shows that this instrument has an uncertainty of ±3.84% for a convective heat flux on the order of 900 W/m2.

  2. Unique surface adsorption behaviors of serum proteins on chemically uniform and alternating surfaces

    NASA Astrophysics Data System (ADS)

    Song, Sheng

    With increasing interests of studying proteins adsorption on the surfaces with nanoscale features in biomedical field, it is crucial to have fundamental understandings on how the proteins are adsorbed on such a surface and what factors contribute to the driving forces of adsorption. Besides, exploring more available nanoscale templates would greatly offer more possibilities one could design surface bio-detection methods with favorable protein-surface interactions. Thus, to fulfill the purpose, the work in this dissertation has been made into three major sections. First, to probe the intermediate states which possibly exist between stable and unstable phases described in mean-field theory diagram, a solvent vapor annealing method is chosen to slowly induce the copolymer polystyrene-block-polyvinylpyridine (PS-b-PVP)'s both blocks undergoing micro-phase separations from initial spherical nanodomains into terminal cylindrical nanodomains. During this process, real time atomic force microscopy (AFM) has been conducted to capture other six intermediate states with different morphologies on the polymeric film surfaces. Secondly, upon recognizing each intermediate state, the solution of immunoglobulin gamma (IgG) proteins has been deposited on the surface and been rinsed off with buffer solution before the protein-bounded surface is imaged by AFM. It has been found IgG showing a strong adsorption preference on PS over P4VP block. Among all the six intermediate states, the proteins are almost exclusively adsorbed on PS nanodomains regardless the concentration and deposition time. Thirdly, a trinodular shape protein fibrinogen (Fg) is selected for investigating how geometry and surface charge of proteins would interplay with cylindrical nanodomains on a surface developed from Polystyrene -block-Poly-(methyl methacrylate) PS-b-PMMA. Also, Fg adsorptions on chemically homogeneous surfaces are included here to have a better contrast of showing how much difference it can make

  3. Uniformity analysis of dielectric barrier discharge (DBD) processed polyethylene terephthalate (PET) surface

    NASA Astrophysics Data System (ADS)

    Liu, Chaozong; Brown, Norman M. D.; Meenan, Brian J.

    2006-01-01

    A dielectric barrier discharge (DBD) plasma, operating in air at atmospheric pressure, has been used to induce changes in the surface properties of polyethylene terephthalate (PET) films. The effects that the key DBD operating parameters: discharge power, processing speed, processing duration, and electrode configurations, have on producing wettability changes in the PET surface region have been investigated. The approach taken involves the application of an Taguchi experimental design and robust analysis methodology. The various data sets obtained from these analyses have been used to studies the effect of the operating parameters on the surface uniformity and efficiency of the said treatment. In general, the results obtained indicate that DBD plasma processing is an effective method for the controlled surface modification of PET. Relatively short exposures to the atmospheric pressure discharge produces significant wettability changes at the polymer film surface, as indicted by pronounced reductions in the water contact angle measured. It was observed that the wettability of the resultant surface shows no significant differences in respect to orientation parallel (L-direction) or perpendicular (T-direction) to the electrode long axis. However, there was significant differences between the data obtained from these two orientations. Analysis of the role of each of the operating parameters concerned shows that they have a selective effectiveness with respect to resultant surface modification in terms of uniformity of modification and wettability. The number of treatment cycles and the electrode configuration used were found to have the most significant effects on the homogeneity of the resultant PET surface changes in L- and T-orientation, respectively. On the other hand, the applied power showed no significant role in this regard. The number of treatment cycles was found to be the dominant factor (at significance level of 0.05) in respect of water contact angle

  4. Uniform semiclassical quantization of regular and chaotic classical dynamics on the Henon-Heiles surface

    NASA Technical Reports Server (NTRS)

    Jaffe, C.; Reinhardt, W. P.

    1982-01-01

    Qualitative arguments are adduced which indicate that the apparently chaotic dynamics on the Henon-Heiles (1964) surface display sufficient regularity on a short to intermediate (but not long) time scale to allow the use of standard EBK quantization techniques. This takes advantage of the remnants of manifold structure implied. A complete uniform semiclassical quantization is performed using the time independent technique of the Birkhoff-Gustavson normal form, which was recently introduced in the context of semiclassical quantization by Swimm and Delos (1977, 1979).

  5. Tin City AFS, Alaska. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1983-04-01

    GL&bAL CLIMATOLOGY 9 RA14CH T AC NG VERSUS Vi’SIBILITY A .FAT"E S[ PfIC /mAC I .17 TI CITY AFS AK 73-74,77-81 T 1b. 3 19.5 17.S 19.5 19.5...2. GOVT ACCESSION NO. 3 RECIPIENT’S CATALOG NUMBER USAFETAC/DS 83017 4. TITLE (d SubtII-)Reised Uniform Summary of Surface 5 TYPE OF REPORT & PERIOD...WINDS PART 0 CEILING VERSUS VISIBILITY PART F STATION PRESSURE SKYCOVER SEA LEVEL PRESSURE STANDARD 3 -HOUR GROUPS All su-nseri- requiring diurnal

  6. Pusan East AFS K-9, Pusan, Korea. Revised Uniform Summary of Surface Weather Observations (RUSSWO)

    DTIC Science & Technology

    1968-02-26

    of this report to th- public at ]are, or by DDC to the National r-chnica] Information Servic - (NTIS). ,ro This technical r-.port has be~n reviewed...USAFETAC/DS-80/032 DATA PROCESSING DIVISION ETAC, USAF Air Weather Service (MAC) REV/ISED UNIFORM SUMMARY OF SURFACE WEATHER OBSERVATIONS PUSAN EAST...8217;rLtAFBIL 2225 EPR 14 CONTROLL INGOFF5ICE NAME’ ANC) AOOAFSS 2RPTL7E USAFETAC/CBD I ___ ____ Air Weather Service (MAC) _𔃿E 7Pr7E7 _ Scott AFB IL 62225

  7. Wurtsmith AFB, Michigan. Revised Uniform Summary of Surface Weather Observations. Parts A-F.

    DTIC Science & Technology

    1987-06-12

    USAFETACITN-63-0I. "AN AID FOR USING THE REVISED UNIFORM SUMMARY OF SURFACE WEATHER OBSERVATIONS" 1RUSSAO. TABLE OF CONTENTS STATION HISTORY C PART A: WEATHER...24 634 OSC STATION LOCATION AND INSTRUMENTATION HISTORY Vitt~f tLAU UELtlNE L~TI EMI AIM WK A.1. U 6itffn maI~t . 041 1 Oscoda AA ich A Jul.43 1 Aug43...fla saiTT[I SUSHI ~ 15658 __________________ 1 Jul 43 1/A N/A 1/A N/A 2 JU 53 Permanently mounted on iop of AN/GMQ-1 ML-204-~1 30 ft the weather

  8. Alconbury RAF United Kingdom Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1984-04-01

    AD A746 q13 ALCONBURY RAF UNITED KINGDOM REVISFD UNIFORM SUMMARY OF 1/5SURFACE WEAIER 0..(t0) AIR FORCE ENVIRONMENTAL I CNICAI APPI CATI(NS CENTER...PROCESSING DIVISION USAFETAC Air Weather Service ( MAC) 0SURFACL V, LI’. ILI, I.LRVATIONS F4 ALCOjIwURY RAF UK HSIA #0362 N 52 22 W 000 13 EIEV 16OFIT EGWZ...A RAIWOKUTNMBS Air Force Environmental Technical Appi. Center Scott AFS, IL 62225 1 1 CONTROLLING OFFICE NAME AND ADDRESS OZ. REPORT DATS USAFETAC

  9. Uniform semiclassical quantization of regular and chaotic classical dynamics on the Henon-Heiles surface

    NASA Technical Reports Server (NTRS)

    Jaffe, C.; Reinhardt, W. P.

    1982-01-01

    Qualitative arguments are adduced which indicate that the apparently chaotic dynamics on the Henon-Heiles (1964) surface display sufficient regularity on a short to intermediate (but not long) time scale to allow the use of standard EBK quantization techniques. This takes advantage of the remnants of manifold structure implied. A complete uniform semiclassical quantization is performed using the time independent technique of the Birkhoff-Gustavson normal form, which was recently introduced in the context of semiclassical quantization by Swimm and Delos (1977, 1979).

  10. Patuxent River NAS, Maryland. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1982-05-14

    products. ENVRDIIXMALISMCUREVISED UNIFORM SUMMARY APPLICATIN cam( OF SURFACE WEATHER OBSERVATIONS HOURLY OBSERVATIONS liour ly observations are defined ...FETACSUFC WID A,. EATH4ER SE4VICE/PI*C PERCENTAGEFREQUENCY, OF WINDSRAC ID DiRECTION AND SPME (FROM HOURLY OMSERYATION) maim utfmMAO ALL WEAT ER 0 851...WINDS A.- !EATHER SCIRVICE/MAC "MMbI4AWE FREQUENCY OF Wile D1REcniON AND SPME Co (FROM HOURLY ONIRVATIONS) !?4’,𔃾U PATUXECNT RI VER #481 MO 73-60 (IIALL

  11. Vance AFB, Enid, Oklahoma. Revised Uniform Summary of Surface Weather Observations (RUSSWO).

    DTIC Science & Technology

    1976-04-07

    NUMBER USAFETAC/DS- 79/014, /, T . 5 TYPE OF REPORT & PERIOD COVERED Revised Uniform Summary of Surface Weather’ F ° Observations (RUSSWO)- Vance AFB...82175164 W640 PAPUUR 13909 7 1VANCE AFE. OKLAFO2’A,/ND T N 36 21 11 09V 5 1307 KEM) STATION LOCATION AND INSTRUMENTATION HISTORY NURSER TYPE AT THIS...Okla. AFB Opt 48 Sep 49 N 36 21 U* 097 55 1290 1287 24 4. Same same Oct 49 Mar 53 same same same same 24 5 . ISame same Apr 53 Mar 57 same same same

  12. Experimental Validation of Normalized Uniform Load Surface Curvature Method for Damage Localization

    PubMed Central

    Jung, Ho-Yeon; Sung, Seung-Hoon; Jung, Hyung-Jo

    2015-01-01

    In this study, we experimentally validated the normalized uniform load surface (NULS) curvature method, which has been developed recently to assess damage localization in beam-type structures. The normalization technique allows for the accurate assessment of damage localization with greater sensitivity irrespective of the damage location. In this study, damage to a simply supported beam was numerically and experimentally investigated on the basis of the changes in the NULS curvatures, which were estimated from the modal flexibility matrices obtained from the acceleration responses under an ambient excitation. Two damage scenarios were considered for the single damage case as well as the multiple damages case by reducing the bending stiffness (EI) of the affected element(s). Numerical simulations were performed using MATLAB as a preliminary step. During the validation experiments, a series of tests were performed. It was found that the damage locations could be identified successfully without any false-positive or false-negative detections using the proposed method. For comparison, the damage detection performances were compared with those of two other well-known methods based on the modal flexibility matrix, namely, the uniform load surface (ULS) method and the ULS curvature method. It was confirmed that the proposed method is more effective for investigating the damage locations of simply supported beams than the two conventional methods in terms of sensitivity to damage under measurement noise. PMID:26501286

  13. Uniform hexagonal graphene flakes and films grown on liquid copper surface

    PubMed Central

    Geng, Dechao; Wu, Bin; Guo, Yunlong; Huang, Liping; Xue, Yunzhou; Chen, Jianyi; Yu, Gui; Jiang, Lang; Hu, Wenping; Liu, Yunqi

    2012-01-01

    Unresolved problems associated with the production of graphene materials include the need for greater control over layer number, crystallinity, size, edge structure and spatial orientation, and a better understanding of the underlying mechanisms. Here we report a chemical vapor deposition approach that allows the direct synthesis of uniform single-layered, large-size (up to 10,000 μm2), spatially self-aligned, and single-crystalline hexagonal graphene flakes (HGFs) and their continuous films on liquid Cu surfaces. Employing a liquid Cu surface completely eliminates the grain boundaries in solid polycrystalline Cu, resulting in a uniform nucleation distribution and low graphene nucleation density, but also enables self-assembly of HGFs into compact and ordered structures. These HGFs show an average two-dimensional resistivity of 609 ± 200 Ω and saturation current density of 0.96 ± 0.15 mA/μm, demonstrating their good conductivity and capability for carrying high current density. PMID:22509001

  14. Experimental validation of normalized uniform load surface curvature method for damage localization.

    PubMed

    Jung, Ho-Yeon; Sung, Seung-Hoon; Jung, Hyung-Jo

    2015-10-16

    In this study, we experimentally validated the normalized uniform load surface (NULS) curvature method, which has been developed recently to assess damage localization in beam-type structures. The normalization technique allows for the accurate assessment of damage localization with greater sensitivity irrespective of the damage location. In this study, damage to a simply supported beam was numerically and experimentally investigated on the basis of the changes in the NULS curvatures, which were estimated from the modal flexibility matrices obtained from the acceleration responses under an ambient excitation. Two damage scenarios were considered for the single damage case as well as the multiple damages case by reducing the bending stiffness (EI) of the affected element(s). Numerical simulations were performed using MATLAB as a preliminary step. During the validation experiments, a series of tests were performed. It was found that the damage locations could be identified successfully without any false-positive or false-negative detections using the proposed method. For comparison, the damage detection performances were compared with those of two other well-known methods based on the modal flexibility matrix, namely, the uniform load surface (ULS) method and the ULS curvature method. It was confirmed that the proposed method is more effective for investigating the damage locations of simply supported beams than the two conventional methods in terms of sensitivity to damage under measurement noise.

  15. Enhancement of the crystallinity of barium titanate by using a uniform barium-carbonate surface coating

    NASA Astrophysics Data System (ADS)

    Chung, Nak-Kwan; Yun, Ju-Young; Kim, Jin-Tae; Park, Jiho

    2017-05-01

    In this work, we modified the surfaces of BaTiO3 particles by using barium acetate and ammonium bicarbonate, and we studied the characteristics and sintering behaviors of the coated BaTiO3 particles. Transmission electron microscopy showed that the resultant coating layer was smooth and uniform without agglomerates. X-ray photoemission spectroscopy analysis also revealed that the surface coating layer was composed of BaCO3. After calcination at 950 °C for 5 hours, the c/ a ratio of the coated particles was found to have increased without size growth while the uncoated particles showed size growth. We finally found that the BaCO3 layer acted as a barrier to inhibit particle growth during calcination.

  16. Electromagnetic and scalar diffraction by a right-angled wedge with a uniform surface impedance

    NASA Technical Reports Server (NTRS)

    Hwang, Y. M.

    1974-01-01

    The diffraction of an electromagnetic wave by a perfectly-conducting right-angled wedge with one surface covered by a dielectric slab or absorber is considered. The effect of the coated surface is approximated by a uniform surface impedance. The solution of the normally incident electromagnetic problem is facilitated by introducing two scalar fields which satisfy a mixed boundary condition on one surface of the wedge and a Neumann of Dirichlet boundary condition on the other. A functional transformation is employed to simplify the boundary conditions so that eigenfunction expansions can be obtained for the resulting Green's functions. The eigenfunction expansions are transformed into the integral representations which then are evaluated asymptotically by the modified Pauli-Clemmow method of steepest descent. A far zone approximation is made to obtain the scattered field from which the diffraction coefficient is found for scalar plane, cylindrical or sperical wave incident on the edge. With the introduction of a ray-fixed coordinate system, the dyadic diffraction coefficient for plane or cylindrical EM waves normally indicent on the edge is reduced to the sum of two dyads which can be written alternatively as a 2 X 2 diagonal matrix.

  17. Instrument for the measurement of heat flux from a surface with uniform temperature

    NASA Astrophysics Data System (ADS)

    Baughn, J. W.; Cooper, D.; Iacovides, H.; Jackson, D.

    1986-05-01

    An instrument for the measurement of heat flux from a surface with a nearly uniform temperature is described. This instrument contains a thin-film electrical resistance heater embedded in a copper cone which is thermally isolated from the surrounding walls. A differential thermocouple between the copper cone and the wall is nulled such that the electrical power becomes a direct measure of the surface heat flux. The advantage of this design over earlier sensors is its modular characteristic and its ability to be flush mounted in an external surface or mounted in the wall of a duct. It has been used to measure the local time-average heat transfer coefficient inside a circular duct. The time constant in this application was 43 s. For these measurements an uncertainty analysis is presented which shows that this instrument has an uncertainty of ±3.6% for a convective heat flux of 342 W/sq m. The major source of uncertainty was the surface area.

  18. Modeling Spiral Galaxy Surface Luminosity to Explain Non-Uniform Inclination Distributions

    NASA Astrophysics Data System (ADS)

    Rozum, Jordan C.; Larson, S. L.

    2014-01-01

    The distribution of spiral and bar galaxy orientations is expected to be uniform. However, analysis of several major galaxy catalogs shows this is not always reflected in data. In an attempt to explain this discrepancy, we have developed a galaxy simulation code to compute the appearance of a spiral type galaxy as a function of its morphological parameters. We examine the dependence of observed brightness upon inclination angle by using smooth luminous mass density and interstellar medium (ISM) density distributions. The luminous mass component is integrated along a particular line of sight, thus producing a mass distribution, from which a surface luminosity profile is derived. The ISM component is integrated alongside the luminous mass component to account for light extinction. Using this model, we present simulated galaxy inclination distributions that account for potential selection effects.

  19. Surface plasmon assisted optical nonlinearities of uniformly oriented metal nano-ellipsoids in glass.

    PubMed

    Mohan, Sabitha; Lange, Jens; Graener, Heinrich; Seifert, Gerhard

    2012-12-17

    The nonlinear optical properties of nanocomposites consisting of non-spherical silver nanoparticles in glass matrix have been studied using the femtosecond Z-scan technique. The spheroidal nanoparticles were uniformly oriented along a common direction. By polarization sensitive studies, longitudinal and transverse plasmon resonances can be addressed separately. A sign reversal in optical nonlinearity from negative to positive is observed while switching the light interaction from near to non-resonant regime, which can be done by simply rotating the light polarization by 90°. Studying samples with different aspect ratio, we obtained the dispersion of third-order nonlinearity in the near-resonant regime, showing an enhancement of the nonlinear processes by more than two orders of magnitude due to the electric field enhancement at the surface plasmon resonance.

  20. Quasi-one-dimensional cyano-phenylene aggregates: Uniform molecule alignment contrasts varying electrostatic surface potential

    NASA Astrophysics Data System (ADS)

    Balzer, Frank; Resel, Roland; Lützen, Arne; Schiek, Manuela

    2017-04-01

    The epitaxial growth of the mono-functionalized para-quaterphenylene molecule CNHP4 on muscovite mica is investigated. The vacuum deposited molecules aggregate into nanofibers of varying morphology. Due to muscovite's cm symmetry, almost mutually parallel fibers grow. Polarized light microscopy together with X-ray diffraction resolves the projected orientation of the molecules on the substrate surface and within the fibers. Several different contact planes with the substrate are detected. For all of them, the molecules orient with their long molecule axis approximately perpendicular to the grooved muscovite direction, so that the alignment of the molecules on the substrate is uniform. Kelvin probe force microscopy finds vastly different electrostatic properties of different fiber types and facets.

  1. Modelling of non-uniform electrical potential barriers for metal surfaces with chemisorbed oxygen

    NASA Astrophysics Data System (ADS)

    Sun, Chang Q.; Bai, Chunli

    1997-07-01

    A modelling approximation regarding the behaviour of electrons on metal surfaces with chemisorbed oxygen is presented. It is suggested that, as consequences of O - metal surface bonding, ionization, polarization and removal of metal atoms cause the non-uniformity in the surface potential barrier (SPB). The inelastic potential is formulated by using a Fermi-type spatial decay and the work function that depends on the occupied density of state. This formulation takes into account that, at energies below the plasma excitation energy, electron excitation dominates and that the electron excitation occurs in the electron-occupied space with any energy greater than the work function. The present modelling method is an improvement in that (i) the elastic potential, the spatial decay and the energy dependence of the inelastic potential are associated with the electron distribution, 0953-8984/9/27/013/img5 (ii) all the SPB parameters are functionalized as dependents of the origin of the image plane, 0953-8984/9/27/013/img6, or the boundary of the region occupied by electrons; (iii) the spatial localization and the variation in energy state are taken into account; and (iv) the single-variable parameterized SPB simplifies the very-low-energy electron diffraction calculations and ensures the uniqueness of the solutions. This method allows us to optimize crystal structures by uniquely comparing the shapes of the geometry-dependent 0953-8984/9/27/013/img7 curves that exhibit joint features of topography and spectroscopy revealed by STM/STS.

  2. Achieving revegetation standards on surface mined lands. [Montana

    SciTech Connect

    Sindelar, B. W.

    1980-01-01

    Standards for revegetation success on surface mined lands have been developed by federal and state regulatory authorities. Because reclamation science is young, its potential for meeting revegetation standards is untested. This paper reviews the Montana revegetation standards which require establishment of a diverse, effective, and permanent vegetational cover. In addition, productivity, cover, and diversity must be comparable to that of reference areas. Fifty-one percent of the cover must be of native species. A plant succession study at Colstrip, MT, has been directed toward documenting establishment, succession, and stability of vegetation on surface mined land. Data from the study were used to discuss success of reclamation seedings since 1969. Major problem areas identified include achieving: comparable life form composition, cover of perennial vegetation, species diversity, and seasonality of forage and browse. Achieving erosion control, comparable production, and native species dominance did not appear to be major problems. Achieving revegetation standards on mined lands in the future will require very specialized reclamation procedures and continued research. Naturally revegetated mined lands at Colstrip indicate good potential for reclamation success.

  3. Rayleigh surface acoustic wave as an efficient heating system for biological reactions: investigation of microdroplet temperature uniformity.

    PubMed

    Roux-Marchand, Thibaut; Beyssen, Denis; Sarry, Frederic; Elmazria, Omar

    2015-04-01

    When a microdroplet is put on the Rayleigh surface acoustic wave path, longitudinal waves are radiated into the liquid and induce several phenomena such as the wellknown surface acoustic wave streaming. At the same time, the temperature of the microdroplet increases as it has been shown. In this paper, we study the temperature uniformity of a microdroplet heated by Rayleigh surface acoustic wave for discrete microfluidic applications such as biological reactions. To precisely ascertain the temperature uniformity and not interfere with the biological reaction, we used an infrared camera. We then tested the temperature uniformity as a function of three parameters: the microdroplet volume, the Rayleigh surface acoustic wave frequency, and the continuous applied radio frequency power. Based on these results, we propose a new device structure to develop a future lab on a chip based on reaction temperatures.

  4. Surface plasmon resonance microscopy: Achieving a quantitative optical response

    NASA Astrophysics Data System (ADS)

    Peterson, Alexander W.; Halter, Michael; Plant, Anne L.; Elliott, John T.

    2016-09-01

    Surface plasmon resonance (SPR) imaging allows real-time label-free imaging based on index of refraction and changes in index of refraction at an interface. Optical parameter analysis is achieved by application of the Fresnel model to SPR data typically taken by an instrument in a prism based figuration. We carry out SPR imaging on a microscope by launching light into a sample and collecting reflected light through a high numerical aperture microscope objective. The SPR microscope enables spatial resolution that approaches the diffraction limit and has a dynamic range that allows detection of subnanometer to submicrometer changes in thickness of biological material at a surface. However, unambiguous quantitative interpretation of SPR changes using the microscope system could not be achieved using the Fresnel model because of polarization dependent attenuation and optical aberration that occurs in the high numerical aperture objective. To overcome this problem, we demonstrate a model to correct for polarization diattenuation and optical aberrations in the SPR data and develop a procedure to calibrate reflectivity to index of refraction values. The calibration and correction strategy for quantitative analysis was validated by comparing the known indices of refraction of bulk materials with corrected SPR data interpreted with the Fresnel model. Subsequently, we applied our SPR microscopy method to evaluate the index of refraction for a series of polymer microspheres in aqueous media and validated the quality of the measurement with quantitative phase microscopy.

  5. Surface plasmon resonance microscopy: achieving a quantitative optical response

    PubMed Central

    Peterson, Alexander W.; Halter, Michael; Plant, Anne L.; Elliott, John T.

    2016-01-01

    Surface plasmon resonance (SPR) imaging allows real-time label-free imaging based on index of refraction, and changes in index of refraction at an interface. Optical parameter analysis is achieved by application of the Fresnel model to SPR data typically taken by an instrument in a prism based configuration. We carry out SPR imaging on a microscope by launching light into a sample, and collecting reflected light through a high numerical aperture microscope objective. The SPR microscope enables spatial resolution that approaches the diffraction limit, and has a dynamic range that allows detection of subnanometer to submicrometer changes in thickness of biological material at a surface. However, unambiguous quantitative interpretation of SPR changes using the microscope system could not be achieved using the Fresnel model because of polarization dependent attenuation and optical aberration that occurs in the high numerical aperture objective. To overcome this problem, we demonstrate a model to correct for polarization diattenuation and optical aberrations in the SPR data, and develop a procedure to calibrate reflectivity to index of refraction values. The calibration and correction strategy for quantitative analysis was validated by comparing the known indices of refraction of bulk materials with corrected SPR data interpreted with the Fresnel model. Subsequently, we applied our SPR microscopy method to evaluate the index of refraction for a series of polymer microspheres in aqueous media and validated the quality of the measurement with quantitative phase microscopy. PMID:27782542

  6. Ag-NP@Ge-nanotaper/Si-micropillar ordered arrays as ultrasensitive and uniform surface enhanced Raman scattering substrates

    NASA Astrophysics Data System (ADS)

    Liu, Jing; Meng, Guowen; Li, Zhongbo; Huang, Zhulin; Li, Xiangdong

    2015-10-01

    Surface-enhanced Raman scattering (SERS) is considered to be an excellent candidate for analytical detection schemes, because of its molecular specificity, rapid response and high sensitivity. Here, SERS-substrates of Ag-nanoparticle (Ag-NP) decorated Ge-nanotapers grafted on hexagonally ordered Si-micropillar (denoted as Ag-NP@Ge-nanotaper/Si-micropillar) arrays are fabricated via a combinatorial process of two-step etching to achieve hexagonal Si-micropillar arrays, chemical vapor deposition of flocky Ge-nanotapers on each Si-micropillar and decoration of Ag-NPs onto the Ge-nanotapers through galvanic displacement. With high density three-dimensional (3D) ``hot spots'' created from the large quantities of the neighboring Ag-NPs and large-scale uniform morphology, the hierarchical Ag-NP@Ge-nanotaper/Si-micropillar arrays exhibit strong and reproducible SERS activity. Using our hierarchical 3D SERS-substrates, both methyl parathion (a commonly used pesticide) and PCB-2 (one congener of highly toxic polychlorinated biphenyls) with concentrations down to 10-7 M and 10-5 M have been detected respectively, showing great potential in SERS-based rapid trace-level detection of toxic organic pollutants in the environment.Surface-enhanced Raman scattering (SERS) is considered to be an excellent candidate for analytical detection schemes, because of its molecular specificity, rapid response and high sensitivity. Here, SERS-substrates of Ag-nanoparticle (Ag-NP) decorated Ge-nanotapers grafted on hexagonally ordered Si-micropillar (denoted as Ag-NP@Ge-nanotaper/Si-micropillar) arrays are fabricated via a combinatorial process of two-step etching to achieve hexagonal Si-micropillar arrays, chemical vapor deposition of flocky Ge-nanotapers on each Si-micropillar and decoration of Ag-NPs onto the Ge-nanotapers through galvanic displacement. With high density three-dimensional (3D) ``hot spots'' created from the large quantities of the neighboring Ag-NPs and large-scale uniform

  7. Non-linear Imaging of Nanoscale Surface Defects on Alphabet Letter Shaped Colloids in a Uniformly Aligned Nematic Liquid Crystal

    NASA Astrophysics Data System (ADS)

    Giller, Julian; Lapointe, Clayton P.; Smalyukh, Ivan I.

    2012-03-01

    The formation of defect structures on the surfaces of colloids immersed in uniformly aligned nematic liquid crystals is a phenomenon which, if better understood, could lead to advances in micro and nanoscale colloidal self assembly techniques. In this study, three photon fluorescence microscopy (3PFM) was used in conjunction with holographic optical tweezers (HOT) in order to stabilize and image surface defects on English alphabet letter shaped colloids suspended in a uniformly aligned nematic liquid crystal. This data made it possible to characterize the location and strength of these defects for a robust variety of shapes. A relationship between particle shape and angle of orientation vs the host nematic was also observed.

  8. Achieving atomistic control in materials processing by plasma-surface interactions

    NASA Astrophysics Data System (ADS)

    Chang, Jeffrey; Chang, Jane P.

    2017-06-01

    The continuous down-scaling of electronic devices and the introduction of functionally improved novel materials require a greater atomic level controllability in the synthesis and patterning of thin film materials, especially with regards to deposition uniformity and conformality as well as etching selectivity and anisotropy. The richness of plasma chemistry and the corresponding plasma-surface interactions provide the much needed processing flexibility and efficacy. To achieve the integration of the novel materials into devices, plasma-enhanced atomic layer processing techniques are emerging as the enabling factors to obtain atomic scale control of complex materials and nanostructures. This review focuses on an overview of the role of respective plasma species involved in plasma-surface interactions, addressing their respective and synergistic effects, which is followed by two distinct applications: plasma-enhanced atomic layer deposition (ALD) and atomic layer etching (ALE). For plasma-enhanced ALD, this review emphasizes the use of plasma chemistry to enable alternative pathways to synthesize complex materials at low temperatures and the challenges associated with deposition conformality. For plasma enabled ALE processes, the review focuses on the surface-specific chemical reactions needed to achieve desirable selectivity and anisotropy.

  9. Highly uniform and reproducible visible to near-infrared vertical-cavity surface-emitting lasers grown by MOVPE

    SciTech Connect

    Hou, H.Q.; Choquette, K.D.; Hammons, B.E.; Breiland, W.G.; Crawford, M.H.; Lear, K.L.

    1997-05-01

    The authors present the growth and characterization of vertical-cavity surface emitting lasers (VCSELs) from visible to near-infrared wavelength grown by metalorganic vapor phase epitaxy. Discussions on the growth issue of VCSEL materials include the control on growth rate and composition using an in situ normal-incidence reflectometer, optimization of ultra-high material uniformity, and comprehensive p- and n-type doping study in AlGaAs by CCl{sub 4} and Si{sub 2}H{sub 6} over the entire Al composition range. They will also demonstrate the recent achievements of selectively-oxidized VCSELs which include the first room-temperature continuous-wave demonstration of all-AlGaAs 700-nm red VCSELs, high-performance n-side up 850-nm VCSELs, and low threshold current and low-threshold voltage 1.06 {micro}m VCSELs using InGaAs/GaAsP strain-compensated quantum wells.

  10. Non-uniform DFB-surface-etched gratings for enhanced performance high power, high brightness broad area lasers

    NASA Astrophysics Data System (ADS)

    Decker, J.; Fricke, J.; Maaßdorf, A.; Erbert, G.; Tränkle, G.; Crump, P.

    2017-02-01

    Monolithic spectral stabilization is demonstrated in narrow-stripe broad-area lasers (NBA) with high power (5W), conversion efficiency (50%) and high brightness, by using optimized high-order surface-etched DFB gratings. However, surface etched gratings introduce a high index contrast into the semiconductor, leading to the scattering losses increasing rapidly with groove etch depth, limiting efficiency and yield. We therefore review progress in the exploitation of novel, non-uniform grating configurations for improved performance. Devices with non-uniform gratings whose groove etch depth decreases toward the front facet (apodized grating) are shown to operate with enhanced spectrally stable power (6W) compared to devices with uniform gratings.

  11. On the Heat Transfer through a Solid Slab Heated Uniformly and Continuously on One of Its Surfaces

    ERIC Educational Resources Information Center

    Marin, E.; Lara-Bernal, A.; Calderon, A.; Delgado-Vasallo, O.

    2011-01-01

    Some peculiarities of the heat transfer through a sample that is heated by the superficial absorption of light energy under continuous uniform illumination are discussed. We explain, using a different approach to that presented in a recent article published in this journal (Salazar "et al" 2010 "Eur. J. Phys." 31 1053-9), that the front surface of…

  12. On the Heat Transfer through a Solid Slab Heated Uniformly and Continuously on One of Its Surfaces

    ERIC Educational Resources Information Center

    Marin, E.; Lara-Bernal, A.; Calderon, A.; Delgado-Vasallo, O.

    2011-01-01

    Some peculiarities of the heat transfer through a sample that is heated by the superficial absorption of light energy under continuous uniform illumination are discussed. We explain, using a different approach to that presented in a recent article published in this journal (Salazar "et al" 2010 "Eur. J. Phys." 31 1053-9), that the front surface of…

  13. The physics and phenomenology of One Atmosphere Uniform Glow Discharge Plasma (OAUGDP™) reactors for surface treatment applications

    NASA Astrophysics Data System (ADS)

    Reece Roth, J.; Rahel, Jozef; Dai, Xin; Sherman, Daniel M.

    2005-02-01

    In this paper, we present data on the physics and phenomenology of plasma reactors based on the One Atmosphere Uniform Glow Discharge Plasma (OAUGDP™) that are useful in optimizing the conditions for plasma formation, uniformity and surface treatment applications. It is shown that the real (as opposed to reactive) power delivered to a reactor is divided between dielectric heating of the insulating material and power delivered to the plasma available for ionization and active species production. A relationship is given for the dielectric heating power input as a function of the frequency and voltage at which the OAUGDP™ discharge is operated.

  14. Additive Manufacturing of 17-4 PH Stainless Steel: Post-processing Heat Treatment to Achieve Uniform Reproducible Microstructure

    NASA Astrophysics Data System (ADS)

    Cheruvathur, Sudha; Lass, Eric A.; Campbell, Carelyn E.

    2016-03-01

    17-4 precipitation hardenable (PH) stainless steel is a useful material when a combination of high strength and good corrosion resistance up to about 315°C is required. In the wrought form, this steel has a fully martensitic structure that can be strengthened by precipitation of fine Cu-rich face-centered cubic phase upon aging. When fabricated via additive manufacturing (AM), specifically laser powder-bed fusion, 17-4 PH steel exhibits a dendritic structure containing a substantial fraction of nearly 50% of retained austenite along with body centered cubic/martensite and fine niobium carbides preferentially aligned along interdendritic boundaries. The effect of post-build thermal processing on the material microstructure is studied in comparison to that of conventionally produced wrought 17-4 PH with the intention of creating a more uniform, fully martensitic microstructure. The recommended stress relief heat treatment currently employed in industry for post-processing of AM 17-4 PH steel is found to have little effect on the as-built dendritic microstructure. It is found that, by implementing the recommended homogenization heat treatment regimen of Aerospace Materials Specification 5355 for CB7Cu-1, a casting alloy analog to 17-4 PH, the dendritic solidification structure is eliminated, resulting in a microstructure containing about 90% martensite with 10% retained austenite.

  15. Passivation of metal surface states: microscopic origin for uniform monolayer graphene by low temperature chemical vapor deposition.

    PubMed

    Jeon, Insu; Yang, Heejun; Lee, Sung-Hoon; Heo, Jinseong; Seo, David H; Shin, Jaikwang; Chung, U-In; Kim, Zheong Gou; Chung, Hyun-Jong; Seo, Sunae

    2011-03-22

    Scanning tunneling microscopy (STM) and density functional theory (DFT) calculations were used to investigate the surface morphology and electronic structure of graphene synthesized on Cu by low temperature chemical vapor deposition (CVD). Periodic line patterns originating from the arrangements of carbon atoms on the Cu surface passivate the interaction between metal substrate and graphene, resulting in flawless inherent graphene band structure in pristine graphene/Cu. The effective elimination of metal surface states by the passivation is expected to contribute to the growth of monolayer graphene on Cu, which yields highly enhanced uniformity on the wafer scale, making progress toward the commercial application of graphene.

  16. General synthesis of uniform metal sulfide colloidal particles via autocatalytic surface growth: a self-correcting system.

    PubMed

    Li, Xin-Hao; Li, Hong-Bin; Li, Guo-Dong; Chen, Jie-Sheng

    2009-04-06

    After decomposition of thiourea (TU) in the presence of various metal cations to form metal sulfide nanoclusters, an autocatalytic reaction between TU and the surface of the as-formed metal sulfide dominates the further growth of these metal sulfide nanoclusters. This autocatalytic surface growth is self-correcting, leading to formation of uniform metal sulfide colloidal particles. The size (from nanometer to micrometer) and shape of the particles are able to be tuned simply by varying the reactant concentration, reaction time, and temperature. More complex anisotropic particles can also be prepared in the autocatalytic surface growth system.

  17. Designing an LED luminaire with balance between uniformity of luminance and illuminance for non-Lambertian road surfaces.

    PubMed

    Teng, Tun-Chien; Sun, Wen-Shing; Lin, Jhih-Li

    2017-04-01

    We present a method of designing a light-emitting diode (LED) luminaire for non-Lambertian road surfaces, in which we optimized the overlap between the lighting areas of a luminaire and its adjacent luminaires to attain balance between uniformity of luminance and illuminance. The goal of the balance is to approach highly uniform luminance and raise illuminance uniformity as high as possible. The optimal illuminance rendered by a single luminaire and the corresponding far-field intensity were derived from the optimal overlap condition, and, thus, the optical model was established. The performance of the model is as follows: overall uniformity of luminance (UO) is 0.91, longitudinal uniformity of Luminance (UL) is 0.92, threshold increment (TI) is 1.64%, uniformity of horizontal illuminance (UHE) is 0.66, and surround ratio (SR) is 0.52. Finally, a compact freeform lens capping an LED was constructed to realize the optical model. The performance of the luminaire designed with arrayed units of an LED capped by the freeform lens is as follows: UO is 0.80, UL is 0.85, TI is 3.57%, UHE is 0.56, and SR is 0.51. In addition, the luminaire provides 19,600 lumens of luminous flux, of which 68% and 54% are projected on the target area and roadway alone, respectively, while 27% is absorbed by the surrounding materials.

  18. An ultrasensitive, uniform and large-area surface-enhanced Raman scattering substrate based on Ag or Ag/Au nanoparticles decorated Si nanocone arrays

    NASA Astrophysics Data System (ADS)

    Zhang, P. P.; Gao, J.; Sun, X. H.

    2015-01-01

    Large-area and highly ordered Si nanocone arrays decorated with Ag or Au/Ag nanoparticles have been fabricated via a mask-free lithography with reaction ion etching, followed by metal deposition process. Ultrasensitive surface enhanced Raman scattering signals with an enhancement factor of 1012 were achieved even at the concentration of the Rhodamine 6G as low as 10-15 M. The surface-enhanced Raman spectroscopy (SERS) substrate was also applied on the detection of Sudan I dye and the Raman signals were substantially enhanced as well. The stability of the SERS substrate can be significantly improved by covering Ag nanoparticles with Au thin layer, which maintain a high SERS performance even after one month storage. This nanofabrication process appears to be a feasible approach to prepare uniform and reproducible SERS-active substrates with high sensitivity and stability for practical SERS applications.

  19. Electrostatic surface waves on a plasma with non-uniform boundary

    NASA Astrophysics Data System (ADS)

    Stenflo, L.; Gradov, O. M.

    1990-10-01

    A new analytical method is introduced to consider electrostatic surface waves propagating on a cold plasma. A very simple dispersion relation is derived for a plasma bounded by two dielectrics. Previous theory for solitary surface waves is also generalized.

  20. Non-uniform Erosion and Surface Evolution of Plasma-Facing Materials for Electric Propulsion

    NASA Astrophysics Data System (ADS)

    Matthes, Christopher Stanley Rutter

    A study regarding the surface evolution of plasma-facing materials is presented. Experimental efforts were performed in the UCLA Pi Facility, designed to explore the physics of plasma-surface interactions. The influence of micro-architectured surfaces on the effects of plasma sputtering is compared with the response of planar samples. Ballistic deposition of sputtered atoms as a result of geometric re-trapping is observed. This provides a self-healing mechanism of micro-architectured surfaces during plasma exposure. This result is quantified using a QCM to demonstrate the evolution of surface features and the corresponding influence on the instantaneous sputtering yield. The sputtering yield of textured molybdenum samples exposed to 300 eV Ar plasma is found to be roughly 1 of the 2 corresponding value of flat samples, and increases with ion fluence. Mo samples exhibited a sputtering yield initially as low as 0.22+/-8%, converging to 0.4+/-8% at high fluence. Although the yield is dependent on the initial surface structure, it is shown to be transient, reaching a steady-state value that is independent of initial surface conditions. A continuum model of surface evolution resulting from sputtering, deposition and surface diffusion is also derived to resemble the damped Kuramoto-Sivashinsky (KS) equation of non-linear dynamics. Linear stability analysis of the evolution equation provides an estimate of the selected wavelength, and its dependence on the ion energy and angle of incidence. The analytical results are confirmed by numerical simulations of the equation with a Fast Fourier Transform method. It is shown that for an initially flat surface, small perturbations lead to the evolution of a selected surface pattern that has nano- scale wavelength. When the surface is initially patterned by other means, the final resulting pattern is a competition between the "templated" pattern and the "self-organized" structure. Potential future routes of research are also

  1. Modelling of contact angle hysteresis on rough, non-uniform and superhydrophobic surfaces with lattice Boltzmann method

    NASA Astrophysics Data System (ADS)

    Kubiak, K. J.; Wilson, M. C. T.; Castrejón-Pita, J. R.; Hutchings, I. M.

    2011-11-01

    Contact Angle Hysteresis (CAH) is usually attributed to surface heterogeneity, contact line pinning, adsorption or interdiffusion. A model of CAH developed recently by Kubiak & Wilson is demonstrated using the lattice Boltzmann method. The model is based on the dynamic surface heterogeneity, reorientation of surface molecules under wetting liquid, physical roughness, chemical heterogeneity and liquid adhesion and evaporation. Once the surface is wetted, the local static contact angle (CA) changes from its advancing value to match the receding static CA over time Ta. When the contact line retracts, the surface recovers its initial properties corresponding to the advancing static CA over time period Te, which corresponds to the physical evaporation. Further development of the model to include surface roughness and chemical heterogeneity is presented. The model shows good agreement with experimental results for several practical configurations i.e. droplet impact and coalescence, drops on tilted surface, and drops on superhydrophobic and non-uniform surfaces etc. The extended model exhibits great potential for predictive modelling using the lattice Boltzmann method, but can be also implemented in other schemes. Research supported by EPSRC EP/F065019/1 and EP/H018913/1.

  2. Pressure fluctuations on the surface of a cylinder in uniform flow

    NASA Technical Reports Server (NTRS)

    Ayoub, A.; Karamcheti, K.

    1976-01-01

    The problem of determining the pressure fluctuations induced on the surface of a cylinder by the fluctuating wake behind it is formulated. A formal solution relating the unsteady surface pressure field to the velocity field in the wake is derived and used to obtain general results independent of cylinder shape and Reynolds number. The case of the circular cylinder is then examined in detail.

  3. Thermal transport due to buoyant flow past a vertical, heated superhydrophobic surface with uniform stream-wise slip

    NASA Astrophysics Data System (ADS)

    Searle, Matthew; Maynes, Daniel; Crockett, Julie

    2016-11-01

    An analytical investigation of thermal transport due to a steady, laminar, buoyancy-driven flow past a vertical superhydrophobic (SHPo) surface was performed. The surface temperature was constant and uniform and exceeded the temperature of the surrounding liquid. Uniform stream-wise hydrodynamic slip and temperature jump are imposed at the wall to model the SHPo surface. Applying an integral analysis within the boundary layer results in a system of differential equations which are solved numerically to obtain boundary layer thickness, maximum velocity in the profile, and local and average values of both the friction coefficient and the Nusselt number. The classical smooth hydrophobic scenario with no-slip and no temperature jump showed excellent agreement with previous analysis of the same problem. The influence of varying temperature jump length on the local and average values of the friction coefficient and the Nusselt number was obtained for Rayleigh number ranging from 104 to 109 and Prandtl number ranging from 2 to 11. Local and average Nusselt numbers decrease dramatically, concomitant with a decrease in the maximum fluid velocity, as the temperature jump length increases. National Science Foundation(NSF) Grant No. CBET-1235881.

  4. An instrument for the measurement of the heat flux distribution along a contour of a surface at uniform temperature

    NASA Astrophysics Data System (ADS)

    Baughn, J. W.; Hoffman, M. A.; Lee, D.

    An instrument for the measurement of the heat flux distribution along an internal or external contour of a surface at uniform temperature is described. The main element in this instrument is an electrically-heated narrow nickel/chromium ribbon which is mounted flush with, but thermally and electrically insulated from, the walls on both sides. The walls are separately heated and are made of a highly conducting material (e.g., aluminum) to insure a uniform temperature. Differential thermocouples are used to measure the temperature difference between the walls and the Ni/Cr ribbon at various positions along the ribbon. The ribbon power is adjusted until the differential temperature is nulled at a particular position on the ribbon. Since conduction along the ribbon is small, the electrical power divided by the sensor area is a direct measure of the surface heat flux at the nulled position. This makes it possible to measure the local time-average heat flux (and the corresponding heat transfer coefficient) at various positions along a contour of a surface. An uncertainty analysis shows that this instrument has an uncertainty of +/- 3.0 percent for a convective heat flux of approximately 874 W/sq m.

  5. Efficient design of experiments for complex response surfaces with application to etching uniformity in a plasma reactor

    NASA Astrophysics Data System (ADS)

    Tatavalli Mittadar, Nirmal

    Plasma etching uniformity across silicon wafers is of paramount importance in the semiconductor industry. The complexity of plasma etching, coupled with lack of instrumentation to provide real-time process information (that could be used for feedback control), necessitate that optimal conditions for uniform etching must be designed into the reactor and process recipe. This is often done empirically using standard design of experiments which, however, are very costly and time consuming. The objective of this study was to develop a general purpose efficient design strategy that requires a minimum number of experiments, and can handle complex constraints in the presence of uncertainties. Traditionally, Response Surface Methodology (RSM) is used in these applications to design experiments to determine the optimal value of decision variables or inputs. We demonstrated that standard RSM, when applied to the problem of plasma etching uniformity, has the following drawbacks (1) inefficient search due to process nonlinearities, (2) lack of converge to the optimum, and, (3) inability to handle complex inequality constraints. We developed a four-phase Efficient Design Strategy (EDS) based on the DACE paradigm (Design and Analysis of Computer Experiments) and Bayesian search algorithms. The four phases of EDS are: (1) exploration of the design space by maximizing information, (2) exploration of the design space for feasible points by maximizing probability of constraint satisfaction, (3) optimization of the objective and (4) constrained local search. We also designed novel algorithms to switch between the different phases. The choice of model parameters for DACE predictors is usually determined by the Maximum Likelihood Estimation (MLE) method. Depending on the dataset, MLE could result in unrealistic predictors that show a peak-and-dip behavior. To solve this problem we developed techniques to detect the presence of peak-and-dip behavior and a new scheme based on Maximum a

  6. Stuttgart Germany/Echterdingen Apt. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    DTIC Science & Technology

    1972-10-31

    DDA-2 OTIC 70A DOCUMENT PROCOESING SKEET OC 7 ADA 0878 17 UA:TCD-~/’ DATA PROCESSING DIVISION USAFETAC Air Weather Service ( MAC) REVISED UNI!FORM...QCCP1C-* CATALO0, %-PE4 USAFETAC/DS- 80/57 A TO’-E 1-d S.b. . -PC r 9t4E q 3p - 7 Revised Uniformn Surmnary of Surface WeatherFilret Observations (RUSSWO...frequency of occuring tables. UN4CLASSIFIED ~ SFCUftSTY CLASIFICATION OF THIS PAGIE(Whon D;0r 4. == ’OI DJII1 REVISED UNIFORM SUMMARY AIRl UUETi S=VICS (PC

  7. Patrick AFB, Cocoa Beach, Florida. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1981-04-14

    AD-AI02 396 AIR FORCE ENVIRONMENTAL TECHNICAL APPLICATIONS CENTER..ETC FO 4/2 PATRICK AFA, COCOA BEACH, FLORIDA. REVISED UNIFORM SUMMARY OF S--ETC(U... COCOA A P_..O_- BEACH, FLORIDA -__N__ O . 6. CONTRkCT OR GRANT NUMB4EA L-. AN-- -. 0. PAO. R:5AR EL.MENT. IRCJ t C. - ,5; AFETAC/01L--A 4RA :R( UNIT...statisitical summary of surface weather observations fer PATRICK AFB, COCOA BEACH, FLORIDA It contains the following parts: (A) Weather Conditions; Atmospheric

  8. John Rodgers WBAS, Honolulu, Hawaii. Revised Uniform Summary of Surface Weather Observations (RUSSWO), Parts A-F

    DTIC Science & Technology

    1967-12-05

    BUILDING "THIS DOCUMFNT HAS BEEN APPROVID FOR PU- SALE; ITS Of i ASHEVILLE, N. C. 0rRIBUTiL-. .v j’LiyUdTED" 10 2 105 9.A,. . zt --. , ~~~~~~~~~~~ - 5 ...TITLF (and Suhblltl) 5 TYPE OF REPORT & PERIOD COVERED Revised Uniform Summary of Surface Weather Observations (RUSSWO)- John Rodgers WBAS, Honolulu...12 REPORT DATE USAFETAC/CBD 5 Dec 67 Air Weather Service (MAC) 13 NUMBER OF PAGES Scott AFB IL 62225 P. 𔃾 MONITORING AGENCY NAME 6 ADORESS(If

  9. Pressure-Sensitive Paint Measurements on Surfaces with Non-Uniform Temperature

    NASA Technical Reports Server (NTRS)

    Bencic, Timothy J.

    1999-01-01

    Pressure-sensitive paint (PSP) has become a useful tool to augment conventional pressure taps in measuring the surface pressure distribution of aerodynamic components in wind tunnel testing. While the PSP offers the advantage of a non-intrusive global mapping of the surface pressure, one prominent drawback to the accuracy of this technique is the inherent temperature sensitivity of the coating's luminescent intensity. A typical aerodynamic surface PSP test has relied on the coated surface to be both spatially and temporally isothermal, along with conventional instrumentation for an in situ calibration to generate the highest accuracy pressure mappings. In some tests however, spatial and temporal thermal gradients are generated by the nature of the test as in a blowing jet impinging on a surface. In these cases, the temperature variations on the painted surface must be accounted for in order to yield high accuracy and reliable data. A new temperature correction technique was developed at NASA Lewis to collapse a "family" of PSP calibration curves to a single intensity ratio versus pressure curve. This correction allows a streamlined procedure to be followed whether or not temperature information is used in the data reduction of the PSP. This paper explores the use of conventional instrumentation such as thermocouples and pressure taps along with temperature-sensitive paint (TSP) to correct for the thermal gradients that exist in aeropropulsion PSP tests. Temperature corrected PSP measurements for both a supersonic mixer ejector and jet cavity interaction tests are presented.

  10. Analytical calculation of electron group velocity surfaces in uniform strained graphene

    NASA Astrophysics Data System (ADS)

    Gómez-Arias, Wilfrido A.; Naumis, Gerardo G.

    2016-12-01

    Electron group velocity for graphene under uniform strain is obtained analytically by using the tight-binding (TB) approximation. Such closed analytical expressions are useful in order to calculate the electronic, thermal and optical properties of strained graphene. These results allow to understand the behavior of electrons when graphene is subjected to strong strain and nonlinear corrections, for which the usual Dirac approach is no longer valid. Some particular cases of uniaxial and shear strain were analyzed. The evolution of the electron group velocity indicates a break-up of the trigonal warping symmetry, which is replaced by a warping consistent with the symmetry of the strained reciprocal lattice. To do this, analytical expressions for the shape of the first Brillouin zone (BZ) of the honeycomb strained reciprocal lattice are provided. Finally, the Fermi velocity becomes strongly anisotropic, i.e., for a strong pure shear strain (20% of the lattice parameter), the two inequivalent Dirac cones merge and the Fermi velocity is zero in one of the principal axis of deformation. We found that nonlinear terms are essential to describe the effects of deformation for electrons near or at the Fermi energy.

  11. Facile fabrication of large-area and uniform silica nanospheres monolayer for efficient surface-enhanced Raman scattering

    NASA Astrophysics Data System (ADS)

    Tang, Junqi; Zhao, Qianrun; Zhang, Ning; Man, Shi-Qing

    2014-07-01

    A large-area efficient surface enhanced Raman scattering (SERS) substrate was deposited by Langmuir-Blodgett (LB) assembly and followed by sputter coating process. The interparticle distance of silica nanospheres was convenient and readily regulated by controlling the surface pressure. After sputter coating with a small amount of gold, the nanocomposite film was formed. The surfaces of nanostructures were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The applicability of the nanostructures as SERS substrates was investigated by adsorption of crystal violet (CV) molecules. Different SERS effects were observed on deposited gold nanostructure upon large-area silica nanospheres monolayer with diameter of 250, 570 and 800 nm. It was also discussed the nanospheres with diameter of 250 nm for the fabrication of ordered arrangement of monolayers at surface pressures of 10-30 mN/m. These substrates with the close-packed nanospheres and sputtering of gold were found to exhibit high and uniform enhancement of the Raman signal across the entire surface. The averaged surface enhancement factor (ASEF) was calculated and discussed. The fabricated nanocomposite structures could be utilized as low-cost SERS-active substrates for biomedical and analytical chemistry field.

  12. Design and experiment of 4H-SiC JBS diodes achieving a near-theoretical breakdown voltage with non-uniform floating limiting rings terminal

    NASA Astrophysics Data System (ADS)

    Yuan, Hao; Song, Qingwen; Tang, Xiaoyan; Zhang, Yimeng; Zhang, Yimen; Zhang, Yuming

    2016-09-01

    In this paper, a 4H-SiC Junction Barrier Schottky diode (JBS) with non-uniform floating limiting rings (FLRs) has been investigated and fabricated using n type 4H-SiC epitaxial layer with thickness of 31 μm and doping concentration of 3.3 × 1015 cm-3. According to the simulated results, the key parameters of a FLRs design to achieve a high voltage are the minimum space between two adjacent doped rings, spacing growth step and number of rings. The experimental results also show a great agreement with simulated results. Meanwhile, a near-ideal breakdown voltage of 3.7 kV was achieved, which yield around 95% of the parallel-plane breakdown voltage. The forward characteristics show that the fabricated JBS diodes have a forward current density of 210 A/cm2 at 3 V and a specific on-resistance (Rsp-on) of 7.58 mΩ cm2. Different FLRs parameters have no effect on the forward device performance.

  13. Scaling evaluation of the effect of surface characteristics on potential for deep convection over uniform terrain

    NASA Technical Reports Server (NTRS)

    Segal, M.; Arritt, R. W.; Clark, C.; Rabin, R.; Brown, J.

    1995-01-01

    The effect of surface characteristics on the daytime change in the potential for development of deep convection resulting from surface flux of heat and moisture is evaluated by conceptual, scaling, and numerical modeling approaches. It is shown that deep convection depends significantly on the Bowen ratio; for smaller Bowen ratio, the thermodynamic potential for deep convection increases. The elevation and the intensity of the capping stable layer have an opposing impact on deep convection: increasing moisture accumulation through evapotranspiration was supportive but was counteracted by the enhancement of dry entrainment. Based on an approximnate treatment of the effect of cloudiness on solar irradiance, it was found that development of fair weather cumulus has a secondary effect on deep convection potential. Observational and operational aspects of the influence of surface conditions on evapotranspiration and development of deep convection are presented.

  14. Improving Morphological Quality and Uniformity of Hydrothermally Grown ZnO Nanowires by Surface Activation of Catalyst Layer

    NASA Astrophysics Data System (ADS)

    Murillo, Gonzalo; Lozano, Helena; Cases-Utrera, Joana; Lee, Minbaek; Esteve, Jaume

    2017-01-01

    This paper presents a study about the dependence of the hydrothermal growth of ZnO nanowires (NWs) with the passivation level of the active surface of the Au catalyst layer. The hydrothermal method has many potential applications because of its low processing temperature, feasibility, and low cost. However, when a gold thin film is utilized as the seed material, the grown NWs often lack morphological homogeneity; their distribution is not uniform and the reproducibility of the growth is low. We hypothesize that the state or condition of the active surface of the Au catalyst layer has a critical effect on the uniformity of the NWs. Inspired by traditional electrochemistry experiments, in which Au electrodes are typically activated before the measurements, we demonstrate that such activation is a simple way to effectively assist and enhance NW growth. In addition, several cleaning processes are examined to find one that yields NWs with optimal quality, density, and vertical alignment. We find cyclic voltammetry measurements to be a reliable indicator of the seed-layer quality for subsequent NW growth. Therefore, we propose the use of this technique as a standard procedure prior to the hydrothermal synthesis of ZnO NWs to control the growth reproducibility and to allow high-yield wafer-level processing.

  15. Improving Morphological Quality and Uniformity of Hydrothermally Grown ZnO Nanowires by Surface Activation of Catalyst Layer.

    PubMed

    Murillo, Gonzalo; Lozano, Helena; Cases-Utrera, Joana; Lee, Minbaek; Esteve, Jaume

    2017-12-01

    This paper presents a study about the dependence of the hydrothermal growth of ZnO nanowires (NWs) with the passivation level of the active surface of the Au catalyst layer. The hydrothermal method has many potential applications because of its low processing temperature, feasibility, and low cost. However, when a gold thin film is utilized as the seed material, the grown NWs often lack morphological homogeneity; their distribution is not uniform and the reproducibility of the growth is low. We hypothesize that the state or condition of the active surface of the Au catalyst layer has a critical effect on the uniformity of the NWs. Inspired by traditional electrochemistry experiments, in which Au electrodes are typically activated before the measurements, we demonstrate that such activation is a simple way to effectively assist and enhance NW growth. In addition, several cleaning processes are examined to find one that yields NWs with optimal quality, density, and vertical alignment. We find cyclic voltammetry measurements to be a reliable indicator of the seed-layer quality for subsequent NW growth. Therefore, we propose the use of this technique as a standard procedure prior to the hydrothermal synthesis of ZnO NWs to control the growth reproducibility and to allow high-yield wafer-level processing.

  16. Investigation and control of the uniformity of drug nanoparticles directly deposited on the particulate surfaces of excipient by PLD

    NASA Astrophysics Data System (ADS)

    Nagare, S.; Sagawa, Jo; Senna, M.

    2007-04-01

    Pulsed laser deposition (PLD) of drug nanoparticles for pharmaceutical preparation was investigated. Indomethacin (IM) was preliminary mixed with magnesium stearate (StMg) to prepare a target for PLD. By using the composite targets, the percentage of deposited nanoparticles in the collected powder increased compared to when only IM was ablated. The percentage of IM nanoparticles was the highest when IM and StMg were mixed at 1:1 ratio. Nanoparticles of the composite target were deposited on the micron sized particulate excipient, i.e., SiO2, potato starch, and lactose. The excipient powders were mixed by rotation. Their surface coverage was evaluated by FE-SEM observation and diffuse reflectance (DR) UV-Vis spectroscopy. The surface coverage was estimated to be around 50 % for 20 min deposition time. Simple rotation of the excipient powders was found to be one of the effective methods for uniform deposition of nanoparticles.

  17. Tight and uniform layer of covalently bound aminoethylophenyl groups perpendicular to gold surface for attachment of biomolecules.

    PubMed

    Fau, Michal; Kowalczyk, Agata; Olejnik, Piotr; Nowicka, Anna M

    2011-12-15

    Strongly adhered layers of the compound with the primary amino group directed toward the solution were obtained at the gold surface by chronoamperometric electroreduction of 4-aminoethylobenzenodiazonium salt (AEBD) in acetonitrile solution at appropriately selected potential. The used techniques (EQCM, AFM, EIS, PM, IRRAS) showed that the nature and thickness of formed aminoethylophenyl layer strongly depend on the potential applied to the electrode. Electroreduction of AEBD salt at a potential more negative than -0.6 V (vs Ag/AgCl) leads to about monolayer on the gold surface. Additionally, such a layer was very tight and uniform. The electrochemical measurements indicate that the efficient and precise attachment of biomolecules to the aminoethylophenyl layer is only possible when this layer is formed at appropriate potential. This was shown for ss- and dsDNA.

  18. Lemoore NAS, California. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1982-11-01

    reported occurrences of thunderstorm, tornado , and waterspout. Rain and/or drizzle - All liquid precipitatiou, falling to the ground, not freezing...OL.A Pei VIuo olf of110. 00 . Foam "I*0 oM 45 PA L CLIMA rOL06Y 3RANCH 2FT, SURFACE WINDS -ATHFR SEVICL/Mac PERCENTAGE FREQUENCY OF WIND DIRECTION AND

  19. Dyess AFB, Texas, Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1983-09-21

    8217 ASCH A;TAC SURFACE WINDS A .. _ATT1F SERVICL./"AC PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 1 ttm 2!;,lo loS- UY - 2 S...month. NOTE: Wet.bulb temperature usually wus not reported prior to 1946 , Relative humidity usually wub not reported prior to 1949, nor subsequent Lo

  20. Simulation optimization of filament parameters for uniform depositions of diamond films on surfaces of ultra-large circular holes

    NASA Astrophysics Data System (ADS)

    Wang, Xinchang; Shen, Xiaotian; Sun, Fanghong; Shen, Bin

    2016-12-01

    Chemical vapor deposition (CVD) diamond films have been widely applied as protective coatings on varieties of anti-frictional and wear-resistant components, owing to their excellent mechanical and tribological properties close to the natural diamond. In applications of some components, the inner hole surface will serve as the working surface that suffers severe frictional or erosive wear. It is difficult to realize uniform depositions of diamond films on surfaces of inner holes, especially ultra-large inner holes. Adopting a SiC compact die with an aperture of V80 mm as an example, a novel filament arrangement with a certain number of filaments evenly distributed on a circle is designed, and specific effects of filament parameters, including the filament number, arrangement direction, filament temperature, filament diameter, circumradius and the downward translation, on the substrate temperature distribution are studied by computational fluid dynamics (CFD) simulations based on the finite volume method (FVM), adopting a modified computational model well consistent with the actual deposition environment. Corresponding temperature measurement experiments are also conducted to verify the rationality of the computational model. From the aspect of depositing uniform boron-doped micro-crystalline, undoped micro-crystalline and undoped fine-grained composite diamond (BDM-UMC-UFGCD) film on such the inner hole surface, filament parameters as mentioned above are accurately optimized and compensated by orthogonal simulations. Moreover, deposition experiments adopting compensated optimized parameters and some typical contrastive parameters are also accomplished for further verifying the rationality of the computational model and the correctness of the compensation coefficient 0.7 defined for the downward translation determined by simulations. More importantly, on the basis of more simulations and verification tests, a general filament arrangement model suitable for V50-120 mm

  1. Hahn AB, Hunsbruck, Germany. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    DTIC Science & Technology

    1978-09-29

    r- . 9* 1 72,1 25.31 23.i’ 2.8 - 1s 1 j1oo.L..LI TOM AQ.WMU Of Q 3~J f USAETAC C-8- mvm twI - co 3 ^ riI * L C SURFACE WINDS PERCENTAGE FREQUFNCY OF...9_9 _7 1 IL.5J 28,4j 36.51 17.7 2.71 100-0 1- TOTAL NUMBER Of OBSERVATIONS 9 3 0 j’ USAFETAC C-8-5 (OL-Al Ptiviou |S toOA1 Of THIAS F A Ml COS .IETI...r T-TltjW:, &W T-- Am, W. tzla - co ctmAn c~t- 3 E1 .’.Js. F SURFACE WINDS AIR ..,FAiFR SLIRVT¢C/ m Ar PERCENTAGE FREQUENCY OF WIND DIRECTION AND

  2. Offutt AFB, Nebraska Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1984-08-01

    category on the foi-ms are listed below: Thunderstorms - All reported occurrences of thunderstorm, tornado , end waterspout. Rain and/or drizzle - A-l...5 (Q. A) ,nHVIuS tIl11IS OF THIS FORM ARI OSSOtItl - - - T --7 41 ’T’IT T r .L’:AL CLIMA &TOLOGY !,,ANPCH C, LP,,E T AC SURFACE WINDS £ AIr. drATHER

  3. The Hydrogen Abstraction from A Diamond(111) Surface in A Uniform Electric Field

    NASA Technical Reports Server (NTRS)

    Ricca, Alessandra; Bauschlicher, Charles W., Jr.; Kang, Jeung Ku.; Musgrave, Charles B.; Arnold, James O. (Technical Monitor)

    1998-01-01

    Bond breaking in a strong electric field is shown to arise from a crossing of the ionic and covalent asymptotes. The specific example of hydrogen abstraction from a diamond(111) surface is studied using a cluster model. The addition of nearby atoms in both the parallel and perpendicular direction to the electric field are found to have an effect. It is also shown that the barrier is not only related to the position of the ionic and covalent asymptotes.

  4. Cape Romanzof AFS, Alaska. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1983-03-01

    to unlimited distribution of this report to the public at large, or by DDC to the National Technical Information Service (NTIS). This techmical...m ,mm~ -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - aI GLOBAL CLIMATOLOGY BRANCH UShCT AC AIR wEATER SERVICe /MAC WEATHER...CLIMATOLOGY BRANCH uSFCETAC SURFACE WINDS AIR WEATER SERVICE /MAC PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 71212c CAPE

  5. Minot AFB, North Dakota. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1983-04-01

    Center (DTIC) to the National Technical Information Service (NTIS). This technical report has been reviewed and is approved for publication. WAYNE E...available from U. S. o-erated stations. The hours used by each service for each period are as follows: A-. Force Stations: U. S. Navy and National ...IL MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANARSIN9S5-0 GLC,3AL CLIMATOLOGY BRANICH USAFETAC SURFACE WINDS AIP oEATHER SERVICE /MAC

  6. Buckley ANGB, Colorado. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1983-09-19

    USAFETAC 0O 8 5 (O. A) - -l~os 1OS OF -S1 FORM ARE OASOtfFI - - -t Ed - Am I - I SlM’ 3 - AL CL14ATCLO Y " ASCH , LT AC SURFACE WINDS A .EATHER...temperature usually was not reported prior to 1946 . Relative humidity usually was nct reported prior to 1949, not subsequent to Jun. 1958j and was

  7. Tatalina AFS, Alaska. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1983-03-01

    occurrences of thunderstorm, tornado , and waterspout. Rain and/or drizzle - AJl liquid precipitation, falling to the ground, not freezing. Freezing rain and/or...USAFETAC | -,3AL CLIMA OLDY BRANICH 2 U.AFETA, SURFACE WINDS Air. ,EAT)r, SERVICE/MA., PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY...86.3 86.9 92.3 93.6 93.6 97.3 96.3 980. .),00.:1J0.3 TOTA NUMBEI Of O.,$VATION$ 515 IjSA UA- A / L 4’AL CLIMA TO1, 6Y BRANCH CEILING VERSUS

  8. Tonopah, Nevada, Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1983-09-21

    various phenwmena !neluded In each category on the forms are listed below: Thunderstorms - All reported occurrences of thunderstorm, tornado , and waterspout...7 ... ... 11101r 9- - --- ------- - - T- T L L CLIMA TOLOGY ?ANCH , t-TAC SURFACE WINDS a 104TAPi S-RVICL/MAC PERCENTAGE FREQUENCY OF WIND DIRECTION...7975 3 5 1; 1 4j 4 CdT C-L AL CLIMA TLOUY F ’)ACH 2 L5 fr -TAC PSYCHROMETRIC SUMMARY T ’ At’ * SF VIC,’/’AC 0 - .oIwg s WET BULB TEMPERATURE DEPRESSION

  9. Revised Uniform Summary of Surface Weather Observations (RUSSWO) Schwaebisch Hall AAF, DL

    DTIC Science & Technology

    1979-08-17

    nu & IVA a Us -i _ C- - - _ I _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ -t - ret*C.-= L ra t W -iTe *- &yLJb A L CL± J L AvT C SURFACE...7jql7.17 71 71 lei ’ 71.1 71o11 71.1 71.1 11 P 7000 73.1 74.2 74.6 0 75.1 7- 75. 2 - 75.23 7s.21 ඓ. 75.; 7F. 6000 75.0 76.2 76.7 77o, 77.3 77,4 77.4 77.4

  10. Fort Sill Oklahoma/Post Field. Revised Uniform Summary of Surface Weather Observations

    DTIC Science & Technology

    1975-06-23

    uvious Willows ow Tnil bIA MI oIW U ~-A -- j f ;746 Y -imir,- 77---~ ( DATA PROCESSING qRAN;C4 1 ~ 1 C/UAF ERVIE/~AC INDSURFACE WINDSARWEATHER EVC /NA...PR "CESS.U 8Ak C ETAC/USAF- SURFACE WINDSAI ETE EVC /A ERETG RQEC FWN DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 1J94 FidAT SILL QKLAIH0M4/P0ST FLO...FcIm An Iomei, -.1- 1 1; X. - ! ;; -~i m *v ’g. i DATA PRUCESSLMG BRAfCri USAF ETAC SIFMC CEILING VERSUS VISIBILITY AIR WEATHER EVC /A 13945 FORT SILL

  11. Microstructure of Cu-Ag Uniform Nanoparticulate Films on Polyurethane 3D Catheters: Surface Properties.

    PubMed

    Rtimi, Sami; Sanjines, Rosendo; Pulgarin, Cesar; Kiwi, John

    2016-01-13

    The preparation, characterization, and antibacterial testing of Cu-Ag sputtered polyurethane (PU) catheters are addressed in this study. PU catheters with different atomic ratios Cu:Ag have been sputtered and led to different optical properties as followed by diffuse reflectance spectroscopy (DRS) and the surface redox properties were also different for different Cu-Ag ratios as observed by X-ray photoelectron spectroscopy (XPS). The surface atomic percentage concentration of the oxidized/reduced C-species originating from bacterial cultures before and after bacterial inactivation were determined on the Cu-Ag PU catheters. The crystallographic properties were determined by X-ray diffraction (XRD). The XRD-diffractogram showed the presence of Cu2O (111), Cu (200), CuO (020), and Ag (111) indicating that Cu nanoparticles present a more crystalline character compared to Ag nanoparticles. Increasing the percentage of Ag in the Cu-Ag films, bigger Ag-particle agglomerates were detected by scanning transmission electron microscopy (STEM) microanalysis confirming the results obtained by AFM. The bacterial inactivation kinetics of the sputtered Cu-Ag films on PU catheters was investigated in detail. Quasi-instantaneous bacterial inactivation kinetics was induced by the sputtered films on PU catheters after optimization of the Cu-Ag film thickness.

  12. Surface hydrophilic modification with a sugar moiety for a uniform-sized polymer molecularly imprinted for phenobarbital in serum.

    PubMed

    Hua, Kuichang; Zhang, Lei; Zhang, Zhenhui; Guo, Yong; Guo, Tianying

    2011-08-01

    A uniform-sized polymer molecularly imprinted for phenobarbital, which is surface modified by a sugar moiety, has been prepared through a two-step swelling polymerization method using polystyrene beads as seeds, phenobarbital as the template, 4-vinylpyridine as a functional monomer, ethylene glycol dimethacrylate as a cross-linker and 2-O-meth-acryloyloxyethoxyl-(2,3,4,6- tetra-O-acetyl-β-d-galactopyranosyl)-(1-4)-2,3,6-tri-O-acetyl-β-d-glucopyranoside as a surface-modifying glycomonomer, respectively. After deprotecting the glycopolymer, a surface sugar moiety-modified, hydrophilic, molecularly imprinted polymer for phenobarbital (glyco-MIP) was obtained. The resulting polymer beads were packed into a stainless steel column to evaluate their chromatographic characteristics by high-performance liquid chromatography (HPLC). Good selectivity for phenobarbital was obtained with the glyco-MIP compared to the unmodified molecularly imprinted polymer, which revealed that the recognition sites of phenobarbital were unchanged with sugar moiety surface modification. Furthermore, bovine serum albumin was almost completely recovered from the glyco-MIP column, which indicates that the glyco-MIP materials can be used to separate and analyze drugs in complex samples, such as biological samples. The results of pretreatment with and analysis of phenobarbital in serum suggest that this material can be used to analyze phenobarbital in serum through a pretreatment and reverse-phase HPLC analysis process. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  13. Deflection of a viscoelastic cantilever under a uniform surface stress: Applications to static-mode microcantilever sensors undergoing adsorption

    NASA Astrophysics Data System (ADS)

    Wenzel, M. J.; Josse, F.; Heinrich, S. M.

    2009-03-01

    The equation governing the curvature of a viscoelastic microcantilever beam loaded with a uniform surface stress is derived. The present model is applicable to static-mode microcantilever sensors made with a rigid polymer, such as SU-8. An analytical solution to the differential equation governing the curvature is given for a specific surface stress representing adsorption of analyte onto the viscoelastic beam's surface. The solution for the bending of the microcantilever shows that, in many cases, the use of Stoney's equation to analyze stress-induced deflection of viscoelastic microcantilevers (in the present case due to surface analyte adsorption) can lead to poor predictions of the beam's response. It is shown that using a viscoelastic substrate can greatly increase sensitivity (due to a lower modulus), but at the cost of a longer response time due to viscoelastic creep in the microcantilever. In addition, the effects of a coating on the cantilever are considered. By defining effective moduli for the coated-beam case, the analytical solution for the uncoated case can still be used. It is found that, unlike the case of a silicon microcantilever, the stress in the coating due to bending of a polymer cantilever can be significant, especially for metal coatings. The theoretical results presented here can also be used to extract time-domain viscoelastic properties of the polymer material from beam response data.

  14. A spatially resolved retarding field energy analyzer design suitable for uniformity analysis across the surface of a semiconductor wafer

    SciTech Connect

    Sharma, S.; Gahan, D. Hopkins, M. B.; Kechkar, S.; Daniels, S.

    2014-04-15

    A novel retarding field energy analyzer design capable of measuring the spatial uniformity of the ion energy and ion flux across the surface of a semiconductor wafer is presented. The design consists of 13 individual, compact-sized, analyzers, all of which are multiplexed and controlled by a single acquisition unit. The analyzers were tested to have less than 2% variability from unit to unit due to tight manufacturing tolerances. The main sensor assembly consists of a 300 mm disk to mimic a semiconductor wafer and the plasma sampling orifices of each sensor are flush with disk surface. This device is placed directly on top of the rf biased electrode, at the wafer location, in an industrial capacitively coupled plasma reactor without the need for any modification to the electrode structure. The ion energy distribution, average ion energy, and average ion flux were measured at the 13 locations over the surface of the powered electrode to determine the degree of spatial nonuniformity. The ion energy and ion flux are shown to vary by approximately 20% and 5%, respectively, across the surface of the electrode for the range of conditions investigated in this study.

  15. A spatially resolved retarding field energy analyzer design suitable for uniformity analysis across the surface of a semiconductor wafer.

    PubMed

    Sharma, S; Gahan, D; Kechkar, S; Daniels, S; Hopkins, M B

    2014-04-01

    A novel retarding field energy analyzer design capable of measuring the spatial uniformity of the ion energy and ion flux across the surface of a semiconductor wafer is presented. The design consists of 13 individual, compact-sized, analyzers, all of which are multiplexed and controlled by a single acquisition unit. The analyzers were tested to have less than 2% variability from unit to unit due to tight manufacturing tolerances. The main sensor assembly consists of a 300 mm disk to mimic a semiconductor wafer and the plasma sampling orifices of each sensor are flush with disk surface. This device is placed directly on top of the rf biased electrode, at the wafer location, in an industrial capacitively coupled plasma reactor without the need for any modification to the electrode structure. The ion energy distribution, average ion energy, and average ion flux were measured at the 13 locations over the surface of the powered electrode to determine the degree of spatial nonuniformity. The ion energy and ion flux are shown to vary by approximately 20% and 5%, respectively, across the surface of the electrode for the range of conditions investigated in this study.

  16. A spatially resolved retarding field energy analyzer design suitable for uniformity analysis across the surface of a semiconductor wafer

    NASA Astrophysics Data System (ADS)

    Sharma, S.; Gahan, D.; Kechkar, S.; Daniels, S.; Hopkins, M. B.

    2014-04-01

    A novel retarding field energy analyzer design capable of measuring the spatial uniformity of the ion energy and ion flux across the surface of a semiconductor wafer is presented. The design consists of 13 individual, compact-sized, analyzers, all of which are multiplexed and controlled by a single acquisition unit. The analyzers were tested to have less than 2% variability from unit to unit due to tight manufacturing tolerances. The main sensor assembly consists of a 300 mm disk to mimic a semiconductor wafer and the plasma sampling orifices of each sensor are flush with disk surface. This device is placed directly on top of the rf biased electrode, at the wafer location, in an industrial capacitively coupled plasma reactor without the need for any modification to the electrode structure. The ion energy distribution, average ion energy, and average ion flux were measured at the 13 locations over the surface of the powered electrode to determine the degree of spatial nonuniformity. The ion energy and ion flux are shown to vary by approximately 20% and 5%, respectively, across the surface of the electrode for the range of conditions investigated in this study.

  17. A uniform geometrical theory of diffraction for an edge in a perfectly conducting surface

    NASA Technical Reports Server (NTRS)

    Kouyoumjian, R. G.; Pathak, P. H.

    1974-01-01

    A compact dyadic diffraction coefficient for electromagnetic waves obliquely incident on a curved edge formed by perfectly conducting curved or plane surfaces is obtained. This diffraction coefficient remains valid in the transition regions adjacent to shadow and reflection boundaries, where the diffraction coefficients of Keller's original theory fail. Our method is based on Keller's method of the canonical problem, which in this case is the perfectly conducting wedge illuminated by plane, cylindrical, conical, and spherical waves. When the proper ray-fixed coordinate system is introduced, the dyadic diffraction coefficient for the wedge is found to be the sum of only two dyads, and it is shown that this is also true for the dyadic diffraction coefficients of higher order edges. One dyad contains the acoustic soft diffraction coefficient; the other dyad contains the acoustic hard diffraction coefficient. The expressions for the acoustic wedge diffraction coefficients contain Fresnel integrals, which ensure that the total field is continuous at shadow and reflection boundaries.

  18. Pope AFB, North Carolina Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1985-03-01

    OL.A IRE.IOA$ E0.T10S 01.S T 04. RtU ASP OOtE)U 6 *L’-AL .LI"!ATCL)GY i %A %Cm 2_T SURFACE WINDS .AT-Fd 1.RV1CL’?1AC PERCENTAGE FREQUENCY OF WIND...DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 72V~ -JP AF-!_~ _________ 7-L_________ tot ST A-T 0 k.I IsA .;T. A .L .LAT" E-’ •_ _-_ SPEED MEAN KNTS 1...0 , T ._ . _ * ,... . K . --- .. j , ,.. ’ . .. , m E¢ 800 1 ,00 2! 6100 9 . t 1200- ___? .. ..00 . . . : 100 2! goo EXAMPLE # 1 lHead ceiling

  19. Daggett Municipal, California. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1982-07-02

    1304 WNW *I 2__ 7,2 5.9 __ __ _ , __,0_InW 6 1 . 4 .6 - t2 * T 9 o1 NNW .1 _ .2 _ 6 ,__.. 1.3 8., TOTAL NUME OF OI.$EVATIO4S 30 USAFETAC OS-5 (OL-AI...1.9 3.0 T2 ; _e _ 1.4 1N5 NS 3.4 7,4 ENE 1.3 1.0 ,*6 *_ 3.0 8.3 E 1.9 2*0 014 _ __, o .T¥ ESE _6 .5 N3 1._ To? SE .8 .3 .3 Too _____ SSE ,3 .3 *1 1 6 S...GLOBAL CLIATLOY BRANCHP T2 USAFETAC SURFACE WINDS AIF- WEATHER SERVICE/MAC PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY

  20. Duluth, Duluth IAP, Minnesota. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1983-08-01

    82 MAY ETY 5?A?=m iln" MGM * ALL WEATHER n.flflliinn 11AM ure LIt..) SPEED MEAN (KNTS) 1-3 4-6 7.10 11-16 17.21 22 - 7 2-33 34-40 41-47 48-355 k5 ...ja% TOTAL ?M 1 OF OURVATWOS th r USAFETAC FOR M S A( o w m mm 0- Iwi.t) coSm .. -.. : L t"to7 - *1* - I, GLOBAL CLINATOL06Y BRANCH AFETAC SURFACE...83.7 63.? 83.7 83.8 > 1 000 1..8.-..P .6. 9w0 83. 84. 85.; 85. a5. 85.2 85.2 85.2 85.3 85.3 85.3 5.3 85.3 85.3 35.8 p C. ~~~~ 800 7180 .1 f- % k5 --Sz

  1. Modification for Uniform Surface of Nafion Ultrathin Film Deposited by Inkjet Printing.

    PubMed

    Guo, Yanglu; Ono, Yutaro; Nagao, Yuki

    2015-09-22

    A lack of knowledge about the features of Nafion confined to ultrathin films at the interface has motivated additional examinations to promote the performance of polymer electrolyte membrane fuel cells (PEMFCs). In this work, we demonstrated the utilization of practical film-forming technique inkjet printing to fabricate a Nafion ultrathin film less than 10 nm thickness. However, the well-known "coffee-ring" effect caused poor quality of the printed pattern, which has restricted its application. This report describes a systematic investigation of necessary parameters such as ink concentration, substrate type, pitch, and offset for printing processes. Furthermore, post-treatment in an ethanol vapor atmosphere exhibited a significant effect on flattening and homogenizing the film surface morphology. Results show that the well-distributed Nafion ultrathin film modified by ethanol vapor annealing manifested much-improved proton conductivity.

  2. Bardenas Reales Range, Spain. Revised Uniform Summary of Surface Weather Observations (Russwo). Parts A-F.

    DTIC Science & Technology

    1975-06-30

    94.9 98.0 98.6, 98.6 98.6, cog.3 000.0. Q .0j 0.0. 0.00.0.00.0 4.96.(),01.6 98.6 96 )9.*3.00.0.00.0 00.0 00.0 001000000.00. 94 𔄃 9$ b9 . 86 9A . n9o0.00...SUMMARY OF SURFACE WEATHER OBSERVATIONS 3 f l 1 8W R ZA LE S T Aw G W.A # 4 0 . N 42 1 W 001 27 F.A’ ~ ~ B8 00 PARTS A, C-F 0 POP FRM HOURLY OMF M...FOG AND OR LOWING AND OR WITH OBST NO OF (L S.T STORMS 1) D0 AN ADO ALAD0 SOWN DRIZZLE DRIZZLE SLEET PRECIF. HAZER SAND TO VISION OBS. _ _ _ I K I

  3. Slim planar apparatus for converting LED light into collimated polarized light uniformly emitted from its top surface.

    PubMed

    Teng, Tun-Chien; Tseng, Li-Wei

    2014-10-20

    This study proposes a slim planar apparatus for converting nonpolarized light from a light-emitting diode (LED) into an ultra-collimated linearly polarized beam uniformly emitted from its top surface. The apparatus was designed based on a folded-bilayer configuration comprising a light-mixing collimation element, polarization conversion element, and polarization-preserving light guide plate (PPLGP) with an overall thickness of 5 mm. Moreover, the apparatus can be extended transversally by connecting multiple light-mixing collimation elements and polarization conversion elements in a side-by-side configuration to share a considerably wider PPLGP, so the apparatus can have theoretically unlimited width. The simulation results indicate that the proposed apparatus is feasible for the maximal backlight modules in 39-inch liquid crystal panels. In the case of an apparatus with a 480 × 80 mm emission area and two 8-lumen LED light sources, the average head-on polarized luminance and spatial uniformity over the emission area was 5000 nit and 83%, respectively; the vertical and transverse angular distributions of the emitting light were only 5° and 10°, respectively. Moreover, the average degree of polarization and energy efficiency of the apparatus were 82% and 72%, respectively. As compared with the high-performance ultra-collimated nonpolarized backlight module proposed in our prior work, not only did the apparatus exhibit outstanding optical performance, but also the highly polarized light emissions actually increased the energy efficiency by 100%.

  4. Selfridge ANGB, Michigan. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1982-04-20

    AN OuOLIT73w 64 - - - -9 - -o - -o - -- - -- - -o- ’-L CL! AT0L~vY FHRNCH TAc SURFACE WINDS ;FAT- iFR SERVIC?/ ,4C PERCENTAGE FREQUENCY OF WIND...SPUD NN|• 7 ’) - 8 1.4 o3 eME 0- . 0 *) 1 .4 .8 A ? 07 9 .1 me.? . 1 .8- .6, 3.4, 1 Em .0 2.2! 1.5 02 A1 .7 " ." Su oL I 1o) 1.3 0 1o4 t Sme A loi...1 ._31 7.6 ENE .5 1.4 1.4 .2 3.4 60 E 1.0 1.5 1.0 .1 3.1 5.3. ( E *9 o7 .5 .1 _.Z ,.8 SE *6 1.1 1.1 02 .__ 3.1 6.3 smE .8 1.1 1.4 es .0 3.9 69 S 1. 30

  5. Highly Uniform and Reproducible Surface Enhanced Raman Scattering on Air-stable Metallic Glassy Nanowire Array

    PubMed Central

    Liu, Xue; Shao, Yang; Tang, Yao; Yao, Ke-Fu

    2014-01-01

    Preparation of surface enhanced Raman scattering (SERS) nanostructures with both high sensitivity as well as high reproducibility has always been difficult and costly for routine SERS detection. Here we demonstrate air-stable metallic glassy nanowire arrays (MGNWAs), which were prepared by a cheap and rapid die nanoimprinting technique, could exhibit high SERS enhancement factor (EF) as well as excellent reproducibility. It shows that Pd40.5Ni40.5P19 MGNWA with nanowires of 55 nm in diameter and 100 nm in pitch possesses high SERS activity with an EF of 1.1 × 105, which is 1–3 orders of magnitudes higher than that of the reported crystal Ni-based nanostructures, and an excellent reproducibility with a relative standard deviation of 9.60% measured by 121 points over an area of 100 μm*100 μm. This method offers an easy, rapid, and low-cost way to prepare highly sensitive and reproducible SERS substrates and makes the SERS more practicable. PMID:25060646

  6. Dobbins AFB, Marietta, Georgia. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    DTIC Science & Technology

    1975-07-15

    SNOW SAND TO VISION OiS. DEC 00-02 .2 12.4 .3 .6 13.2 18.3 1.0 19.0 1586 03-05 .1 12o4 .3 .6 13.1 20.4 .8 21.1 1582 06-OR .1 12.2 .4 1.1 13.4 27.3...OBSERVATIONS 1582 USAFETAC FORM 0-8.5 (I. A) PREVIOUS IUITIOS Of THS FORM All cImill AA 64’ -77ś 15Q11-vnm 1- DATA PROCESSING BRANCH 2 ETAC/USAF SURFACE...OF NO OF 3 6 7 8 9 10 SYOE R DEC 0-02 37.9 1.2 2.5 3.1 2.1 1.6 2.6 3.2 4.0 1.9 39.9 5... 1582 P3-05 37.2 1.6 2.2 1.6 2.3 2.2 1. 6 2.5 4.4 1.4 43.4 5.4

  7. A simple additive-free approach for the synthesis of uniform manganese monoxide nanorods with large specific surface area

    PubMed Central

    2013-01-01

    A simple additive-free approach is developed to synthesize uniform manganese monoxide (MnO) one-dimensional nanorods, in which only manganese acetate and ethanol were used as reactants. The as-synthesized MnO nanorods were characterized in detail by X-ray diffraction, scanning and transmission electron microscopy (TEM) including high-resolution TEM and selected-area electron diffraction, Fourier transform infrared spectrum, and nitrogen adsorption isotherm measurements. The results indicate that the as-synthesized MnO nanorods present a mesoporous characteristic with large specific surface area (153 m2 g−1), indicating promising applications in catalysis, energy storage, and biomedical image. On the basis of experimental results, the formation mechanism of MnO one-dimensional nanorods in the absence of polymer additives was also discussed. PMID:23578214

  8. Uniform magnesium oxide adsorbents

    NASA Technical Reports Server (NTRS)

    Dash, J. G.; Ecke, R.; Stoltenberg, J.; Vilches, O. E.; Whittemore, O. J., Jr.

    1978-01-01

    Kr adsorption on MgO is used to characterize the surface uniformity of MgO smoke and thermally decomposed Mg(OH)2. It is found that initially heterogeneous samples develop progressively sharper stepwise isotherms with increasingly-high-temperature heat treatment, apparently due to the removal of imperfections and high-energy facets, leaving surfaces of highly uniform (100) planes.

  9. Facility for Measuring the Spatial Uniformity of the Radiation Power of the Surface of the Large-Area Blackbody

    NASA Astrophysics Data System (ADS)

    Morozova, S. P.; Dunaev, A. Y.; Katysheva, A. A.; Sapritsky, V. I.; Parfentyev, N. A.; Ogarev, S. A.; Karpunin, D. N.

    2017-05-01

    The new stage of the development of space-borne information systems is the creation of the Global Earth Observation System. For the full functioning of such a system, it is necessary to provide the uniformity of measurements of all national systems as members of the global system, with high-quality measurement data. This requires the implementation of a high level of ground (prelaunch) calibration of Earth remote sensing instruments. To solve these problems, there were created calibration facilities on the basis of large vacuum chambers with vacuum reference radiation sources, including sources on the basis of black bodies with a wide aperture of 500 mm in the spectral range from 3 {μ}m to 14 {μ}m. Such a facility was created by FGUP "VNIIOFI" in cooperation with FGUP "TsNIIMash". The ground calibration of Earth remote sensing instruments is being carried out by using blackbody models as radiation sources with known spectral radiance. Facility for ground calibration of remote sensing devices on spectral radiance is based on the usage of a large-aperture blackbody (LABB) with 500 mm diameter and working temperature range from 213 K to 423 K, as a radiation source. This calibration setup comprises a set of reference blackbodies, such as a blackbody on the phase transition of Gallium, a variable-temperature blackbody with temperature range from 213 K to 423 K, a reference blackbody cooled with liquid nitrogen, and IR Fourier spectrometer utilized as a comparator to perform LABB calibration on spectral radiance. The second important characteristic of LABB is the uniformity of spectral radiance across the radiating aperture of this blackbody. The paper describes the device for measuring the spatial homogeneity of the radiation power of the LABB's radiating surface. This device is based on the use of two-color InSb-CdHgTe detector equipped with modulator and IR lens, which are mounted on a two-axis translation stage suitable for operation in vacuum and installed in the

  10. Development of attenuation and diffraction corrections for linear and nonlinear Rayleigh surface waves radiating from a uniform line source

    SciTech Connect

    Jeong, Hyunjo Cho, Sungjong; Zhang, Shuzeng; Li, Xiongbing

    2016-04-15

    In recent studies with nonlinear Rayleigh surface waves, harmonic generation measurements have been successfully employed to characterize material damage and microstructural changes, and found to be sensitive to early stages of damage process. A nonlinearity parameter of Rayleigh surface waves was derived and frequently measured to quantify the level of damage. The accurate measurement of the nonlinearity parameter generally requires making corrections for beam diffraction and medium attenuation. These effects are not generally known for nonlinear Rayleigh waves, and therefore not properly considered in most of previous studies. In this paper, the nonlinearity parameter for a Rayleigh surface wave is defined from the plane wave displacement solutions. We explicitly define the attenuation and diffraction corrections for fundamental and second harmonic Rayleigh wave beams radiated from a uniform line source. Attenuation corrections are obtained from the quasilinear theory of plane Rayleigh wave equations. To obtain closed-form expressions for diffraction corrections, multi-Gaussian beam (MGB) models are employed to represent the integral solutions derived from the quasilinear theory of the full two-dimensional wave equation without parabolic approximation. Diffraction corrections are presented for a couple of transmitter-receiver geometries, and the effects of making attenuation and diffraction corrections are examined through the simulation of nonlinearity parameter determination in a solid sample.

  11. Reliable solution processed planar perovskite hybrid solar cells with large-area uniformity by chloroform soaking and spin rinsing induced surface precipitation

    SciTech Connect

    Chern, Yann-Cherng; Wu, Hung-Ruei; Chen, Yen-Chu; Horng, Sheng-Fu; Zan, Hsiao-Wen; Meng, Hsin-Fei

    2015-08-15

    A solvent soaking and rinsing method, in which the solvent was allowed to soak all over the surface followed by a spinning for solvent draining, was found to produce perovskite layers with high uniformity on a centimeter scale and with much improved reliability. Besides the enhanced crystallinity and surface morphology due to the rinsing induced surface precipitation that constrains the grain growth underneath in the precursor films, large-area uniformity with film thickness determined exclusively by the rotational speed of rinsing spinning for solvent draining was observed. With chloroform as rinsing solvent, highly uniform and mirror-like perovskite layers of area as large as 8 cm × 8 cm were produced and highly uniform planar perovskite solar cells with power conversion efficiency of 10.6 ± 0.2% as well as much prolonged lifetime were obtained. The high uniformity and reliability observed with this solvent soaking and rinsing method were ascribed to the low viscosity of chloroform as well as its feasibility of mixing with the solvent used in the precursor solution. Moreover, since the surface precipitation forms before the solvent draining, this solvent soaking and rinsing method may be adapted to spinless process and be compatible with large-area and continuous production. With the large-area uniformity and reliability for the resultant perovskite layers, this chloroform soaking and rinsing approach may thus be promising for the mass production and commercialization of large-area perovskite solar cells.

  12. Uniform nanoparticles building Ce1- x Pr x O2-δ mesoarchitectures: structure, morphology, surface chemistry, and catalytic performance

    NASA Astrophysics Data System (ADS)

    Somacescu, Simona; Parvulescu, Viorica; Calderon-Moreno, Jose Maria; Suh, Soong-Hyuck; Osiceanu, Petre; Su, Bao-Lian

    2012-06-01

    Ce1- x Pr x O2-δ ( x = 0, 0.1, 0.5, 0.9) mesoarchitectures built from nanoparticles with crystalline framework have been synthesized by the self-assembly method assisted by surfactants and hydrothermal treatment. Cetyltrimethylammonium bromide (CTAB) was used as template, urea as hydrolyzing agent and tetraethylammonium hydroxide (TEAOH) as pH mediator to obtain pH 9. The inorganic precursors have been co-assembled with surfactant template to produce mesoarchitectures which have uniform pore size distribution, crystalline channel walls, high thermal stability, and high catalytic activity in the oxidation reaction of methane. The resulting powders, calcined at 550 °C, were characterized by X-ray diffraction (XRD), Raman spectroscopy, N2 adsorption/desorption isotherms (BET), thermogravimetric analysis (TG-DTG), scanning and transmission electron microscopy (SEM, TEM, and HRTEM), and X-ray photoelectron spectroscopy (XPS). The as-synthesized mesoporous nanoparticles are single-phase fluorite Ce1- x Pr x O2-δ solid solution without additional Ce- or Pr-based oxides, or secondary phases with different lattice symmetry or stoichiometry. A clear morphology of dispersed nanoparticles, with uniform grain size between 5 and 7 nm, and mean pore size around 5 nm, have been observed. The specific surface area of the as-synthesized mesoporous samples after calcination at 550 °C remains in the range 60-150 m2 g-1. All the spectroscopic methods clearly confirm the homogeneous incorporation of Pr into the CeO2 lattice of the nanocrystallites, to form a single-phase solid solution with fluorite structure, modifying the absorption spectra of the nanocrystallites. All the samples showed high catalytic activity in the oxidation reactions of methane.

  13. Method for depositing a uniform layer of particulate material on the surface of an article having interconnected porosity

    DOEpatents

    Wrenn, G.E. Jr.; Lewis, J. Jr.

    1982-09-29

    The invention is a method for depositing liquid-suspended particles on an immersed porous article characterized by interconnected porosity. In one form of the invention, coating is conducted in a vessel containing an organic liquid supporting a colloidal dispersion of graphite sized to lodge in surface pores of the article. The liquid comprises a first volatile component (e.g., acetone) and a second less-volatile component (e.g., toluene) containing a dissolved organic graphite-bonding agent. The liquid also contains an organic agent (e.g., cellulose gum) for maintaining the particles in suspension. A porous carbon article to be coated is immersed in the liquid so that it is permeated therewith. While the liquid is stirred to maintain a uniform blend, the vessel headspace is evacuated to effect flashing-off of the first component from the interior of the article. This causes particle-laden liquid exterior of the article to flow inwardly through its surface pores, lodging particles in these pores and forming a continuous graphite coating. The coated article is retrieved and heated to resin-bond the graphite. The method can be used to form a smooth, adherent, continuous coating of various materials on various porous articles. The method is rapid and reproducible.

  14. Uniform implantation of CNTs on total activated carbon surfaces: a smart engineering protocol for commercial supercapacitor applications

    NASA Astrophysics Data System (ADS)

    Jiang, Jian; Li, Linpo; Liu, Yani; Liu, Siyuan; Xu, Maowen; Zhu, Jianhui

    2017-04-01

    The main obstacles to building better supercapacitors are still trade-offs between energy and power parameters. To promote commercial supercapacitor behaviors, proper optimization toward electrode configurations/architectures may be a feasible and effective way. We herein propose a smart and reliable electrode engineering protocol, by in situ implantation of carbon nanotubes (CNTs) on total activated carbon (AC) surfaces via a mild chemical vapor deposition process at ∼550 °C, using nickel nitrate hydroxide (NNH) thin films and waste ethanol solvents as the catalyst and carbon sources, respectively. The direct and conformal growth of NNH layers onto carbonaceous scaffold guarantees the later uniform implantation of long and high-quality CNTs on total AC outer surfaces. Such fluffy and entangled CNTs preserve ionic diffusion channels, well connect neighboring ACs and function as superhighways for electrons transfer, endowing electrodes with outstanding capacitive behaviors including large output capacitances of ∼230 F g‑1 in 1 M Na2SO4 neutral solution and ∼502.5 F g‑1 in 6 M KOH using Ni valence state variation, and very negligible capacity decay in long-term cycles. Furthermore, a full symmetric supercapacitor device of CNTs@ACs//CNTs@ACs has been constructed, capable of delivering both high specific energy and power densities (maximum values reaching up to ∼97.2 Wh kg‑1 and ∼10.84 kW kg‑1), which holds great potential in competing with current mainstream supercapacitors.

  15. Method for depositing a uniform layer of particulate material on the surface of an article having interconnected porosity

    DOEpatents

    Wrenn, Jr., George E.; Lewis, Jr., John

    1984-01-01

    The invention is a method for depositing liquid-suspended particles on an immersed porous article characterized by interconnected porosity. In one form of the invention, coating is conducted in a vessel containing an organic liquid supporting a colloidal dispersion of graphite sized to lodge in surface pores of the article. The liquid comprises a first volatile component (e.g., acetone) and a second less-volatile component (e.g., toluene) containing a dissolved organic graphite-bonding agent. The liquid also contains an organic agent (e.g., cellulose gum) for maintaining the particles in suspension. A porous carbon article to be coated is immersed in the liquid so that it is permeated therewith. While the liquid is stirred to maintain a uniform blend, the vessel headspace is evacuated to effect flashing-off of the first component from the interior of the article. This causes particle-laden liquid exterior of the article to flow inwardly through its surface pores, lodging particles in these pores and forming a continuous graphite coating. The coated article is retrieved and heated to resin-bond the graphite. The method can be used to form a smooth, adherent, continuous coating of various materials on various porous articles. The method is rapid and reproducible.

  16. Uniform implantation of CNTs on total activated carbon surfaces: a smart engineering protocol for commercial supercapacitor applications.

    PubMed

    Jiang, Jian; Li, Linpo; Liu, Yani; Liu, Siyuan; Xu, Maowen; Zhu, Jianhui

    2017-04-07

    The main obstacles to building better supercapacitors are still trade-offs between energy and power parameters. To promote commercial supercapacitor behaviors, proper optimization toward electrode configurations/architectures may be a feasible and effective way. We herein propose a smart and reliable electrode engineering protocol, by in situ implantation of carbon nanotubes (CNTs) on total activated carbon (AC) surfaces via a mild chemical vapor deposition process at ∼550 °C, using nickel nitrate hydroxide (NNH) thin films and waste ethanol solvents as the catalyst and carbon sources, respectively. The direct and conformal growth of NNH layers onto carbonaceous scaffold guarantees the later uniform implantation of long and high-quality CNTs on total AC outer surfaces. Such fluffy and entangled CNTs preserve ionic diffusion channels, well connect neighboring ACs and function as superhighways for electrons transfer, endowing electrodes with outstanding capacitive behaviors including large output capacitances of ∼230 F g(-1) in 1 M Na2SO4 neutral solution and ∼502.5 F g(-1) in 6 M KOH using Ni valence state variation, and very negligible capacity decay in long-term cycles. Furthermore, a full symmetric supercapacitor device of CNTs@ACs//CNTs@ACs has been constructed, capable of delivering both high specific energy and power densities (maximum values reaching up to ∼97.2 Wh kg(-1) and ∼10.84 kW kg(-1)), which holds great potential in competing with current mainstream supercapacitors.

  17. An Investigation of Techniques for Achieving Exposed Aggregate Surfaces for Site-Cast Concrete

    DTIC Science & Technology

    1975-06-01

    obtaining concrete structures free of placement defects is the use of cast- in-place exposed aggregate . Objective. The objective of this investigation...7 AD-A012 110 AN INVESTIGATION OF TECHNIQUES FOR ACHIEVING EXPOSED AGGREGATE SURFACES FOR SITE-CAST CONCRETE Daniel J. Naus, et...research laboratory TECHNICAL REPORT M-61 (RevlMd) June 1975 w AN INVESTIGATION OF TECHNIQUES FOR ACHIEVING EXPOSED AGGREGATE SURFACES FOR SITE

  18. School Uniforms. Research Brief

    ERIC Educational Resources Information Center

    Walker, Karen

    2007-01-01

    Does clothing make the person or does the person make the clothing? How does what attire a student wears to school affect their academic achievement? In 1996, President Clinton cited examples of school violence and discipline issues that might have been avoided had the students been wearing uniforms ("School uniforms: Prevention or suppression?").…

  19. Achieving Ultralow Fouling under Ambient Conditions via Surface-Initiated ARGET ATRP of Carboxybetaine.

    PubMed

    Hong, Daewha; Hung, Hsiang-Chieh; Wu, Kan; Lin, Xiaojie; Sun, Fang; Zhang, Peng; Liu, Sijun; Cook, Keith E; Jiang, Shaoyi

    2017-03-22

    We achieved ultralow fouling on target surfaces by controlled polymerization of carboxybetaine under ambient conditions. The polymerization process for grafting polymer films onto the surfaces was carried out in air and did not require any deoxygenation step or specialized equipment. This method allows one to conveniently introduce a nonfouling polymer network onto large substrates.

  20. Fast and eco-friendly fabrication of uniform Ag substrates for highly sensitive surface-enhanced Raman scattering

    NASA Astrophysics Data System (ADS)

    Xu, Yongda; Li, Xin; Jiang, Lan; Meng, Ge; Ran, Peng; Lu, Yongfeng

    2017-05-01

    This study proposed a fast, simple, eco-friendly method for obtaining highly sensitive and uniform surface-enhanced Raman scattering (SERS) of silver (Ag) nanotextured substrates decorated with silver nanoparticles in open air. By splitting conventional femtosecond pulses (subpulse delay Δt = 0 ps) into pulse trains (subpulse delay Δt = 3 ps), the mean diameter of Ag nanoparticles was reduced by almost half and the amount of Ag nanoparticles with a diameter ranging from 20 to 60 nm was increased by more than 11 times. The substrate fabricated by femtosecond pulse trains has four main merits as follows: (1) High sensitivity: the maximum SERS enhancement factor is 1.26 × 109; (2) High efficiency: the fabrication rate can be up to 1600 μm2/s, which is 20-40 times faster than femtosecond photochemical reduction; (3) Good reproducibility: the relative standard deviation of the Raman signal intensity is 10.7%, which is one-third of that for conventional femtosecond laser; (4) Eco-friendly fabrication: neither chemical reagents nor vacuum conditions are needed during the fabrication process.

  1. Single and Double ITCZ in Aqua-Planet Models with Globally Uniform Sea Surface Temperature and Solar Insolation: An Interpretation

    NASA Technical Reports Server (NTRS)

    Chao, Winston C.; Chen, Baode; Einaudi, Franco (Technical Monitor)

    2001-01-01

    It has been known for more than a decade that an aqua-planet model with globally uniform sea surface temperature and solar insolation angle can generate ITCZ (intertropical convergence zone). Previous studies have shown that the ITCZ under such model settings can be changed between a single ITCZ over the equator and a double ITCZ straddling the equator through one of several measures. These measures include switching to a different cumulus parameterization scheme, changes within the cumulus parameterization scheme, and changes in other aspects of the model design such as horizontal resolution. In this paper an interpretation for these findings is offered. The latitudinal location of the ITCZ is the latitude where the balance of two types of attraction on the ITCZ, both due to earth's rotation, exists. The first type is equator-ward and is directly related to the earth's rotation and thus not sensitive to model design changes. The second type is poleward and is related to the convective circulation and thus is sensitive to model design changes. Due to the shape of the attractors, the balance of the two types of attractions is reached either at the equator or more than 10 degrees away from the equator. The former case results in a single ITCZ over the equator and the latter case a double ITCZ straddling the equator.

  2. Achieving an ultra-uniform diffraction pattern of stray light with metallic meshes by using ring and sub-ring arrays.

    PubMed

    Lu, Zhengang; Wang, Heyan; Tan, Jiubin; Ma, Limin; Lin, Shen

    2016-05-01

    We provide theoretical and experimental evidence that introducing metallic rings and sub-rings in mesh unit cells significantly decreases the high-order diffraction energy. Moreover, rotating the sub-rings results in increased uniformity in the diffraction distribution without affecting the transmittance. Experiments show that the triangular ring mesh with rotated sub-rings exhibits a normalized visible transmittance greater than 95% as well as an ultra-uniform diffraction pattern of stray light, whose maximal normalized high-order diffraction energy is lower than 0.0167%. This kind of metallic mesh will be favorable in transparent electromagnetic interference shielding devices and touch screens.

  3. Relative roles of differential SST warming, uniform SST warming and land surface warming in determining the Walker circulation changes under global warming

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Li, Tim

    2017-02-01

    Most of CMIP5 models projected a weakened Walker circulation in tropical Pacific, but what causes such change is still an open question. By conducting idealized numerical simulations separating the effects of the spatially uniform sea surface temperature (SST) warming, extra land surface warming and differential SST warming, we demonstrate that the weakening of the Walker circulation is attributed to the western North Pacific (WNP) monsoon and South America land effects. The effect of the uniform SST warming is through so-called "richest-get-richer" mechanism. In response to a uniform surface warming, the WNP monsoon is enhanced by competing moisture with other large-scale convective branches. The strengthened WNP monsoon further induces surface westerlies in the equatorial western-central Pacific, weakening the Walker circulation. The increase of the greenhouse gases leads to a larger land surface warming than ocean surface. As a result, a greater thermal contrast occurs between American Continent and equatorial Pacific. The so-induced zonal pressure gradient anomaly forces low-level westerly anomalies over the equatorial eastern Pacific and weakens the Walker circulation. The differential SST warming also plays a role in driving low-level westerly anomalies over tropical Pacific. But such an effect involves a positive air-sea feedback that amplifies the weakening of both east-west SST gradient and Pacific trade winds.

  4. Relative roles of differential SST warming, uniform SST warming and land surface warming in determining the Walker circulation changes under global warming

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Li, Tim

    2016-04-01

    Most of CMIP5 models projected a weakened Walker circulation in tropical Pacific, but what causes such change is still an open question. By conducting idealized numerical simulations separating the effects of the spatially uniform sea surface temperature (SST) warming, extra land surface warming and differential SST warming, we demonstrate that the weakening of the Walker circulation is attributed to the western North Pacific (WNP) monsoon and South America land effects. The effect of the uniform SST warming is through so-called "richest-get-richer" mechanism. In response to a uniform surface warming, the WNP monsoon is enhanced by competing moisture with other large-scale convective branches. The strengthened WNP monsoon further induces surface westerlies in the equatorial western-central Pacific, weakening the Walker circulation. The increase of the greenhouse gases leads to a larger land surface warming than ocean surface. As a result, a greater thermal contrast occurs between American Continent and equatorial Pacific. The so-induced zonal pressure gradient anomaly forces low-level westerly anomalies over the equatorial eastern Pacific and weakens the Walker circulation. The differential SST warming also plays a role in driving low-level westerly anomalies over tropical Pacific. But such an effect involves a positive air-sea feedback that amplifies the weakening of both east-west SST gradient and Pacific trade winds.

  5. A modification of the epidermal scarification model of herpes simplex virus infection to achieve a reproducible and uniform progression of disease.

    PubMed

    Goel, Neena; Docherty, John J; Fu, Ming Ming; Zimmerman, Daniel H; Rosenthal, Kenneth S

    2002-12-01

    A slight modification in the method used to remove the top keratinized layer of skin in the epidermal scarification model of HSV infection results in an easier, less painful, more uniform and reproducible means of infection. The back of mice was depilated and the top skin layer was removed either by scratching with the side of a 26 gauge needle, or by abrading with sand paper or a hand held motorized pedicure/manicure instrument. The virus was then applied on the scarified or abraded skin and the mice were observed for lesion development from day 3 to 10 post-infection. A uniform pattern of lesion development in terms of onset of lesions by day 3, progression to zosteriform by day 5 occurred for mice whose skin was abraded whereas variability in the time course, progression of symptoms and greater trauma occurred for mice whose skin was scratched with needle. Copyright 2002 Elsevier Science B.V.

  6. The Quest for Nonthrombotic Surface Modifications to Achieve Hemocompatibility of Implantable Devices.

    PubMed

    Tchouta, Lise Nadine; Bonde, Pramod Narayan

    2015-01-01

    The use of blood-contacting implantable devices is limited by surface-induced thrombosis, which has led to the development of thromboresistant surfaces. Multidisciplinary efforts have promoted the development of surface modifications to minimize thrombosis by targeting surface-induced coagulation. To this date, no material has been identified that remains irrevocably hemocompatible with time but many options are now available with their own limitations. Essential to this review is the understanding of some of the challenges in this field and newer opportunities for hemocompatibility research. This report will also briefly review many of the achievements in the development of hemocompatible biomaterial coating, including surface modifications against protein adsorption and platelet adhesion, biomimetism, and endothelialization.

  7. Marcus-Hush-Chidsey theory of electron transfer to and from species bound at a non-uniform electrode surface: Theory and experiment

    NASA Astrophysics Data System (ADS)

    Henstridge, Martin C.; Batchelor-McAuley, Christopher; Gusmão, Rui; Compton, Richard G.

    2011-11-01

    Two simple models of electrode surface inhomogeneity based on Marcus-Hush theory are considered; a distribution in formal potentials and a distribution in electron tunnelling distances. Cyclic voltammetry simulated using these models is compared with that simulated using Marcus-Hush theory for a flat, uniform and homogeneous electrode surface, with the two models of surface inhomogeneity yielding broadened peaks with decreased peak-currents. An edge-plane pyrolytic graphite electrode is covalently modified with ferrocene via 'click' chemistry and the resulting voltammetry compared with each of the three previously considered models. The distribution of formal potentials is seen to fit the experimental data most closely.

  8. Achieving tunable surface tension in the pseudopotential lattice Boltzmann modeling of multiphase flows

    NASA Astrophysics Data System (ADS)

    Li, Qing; Luo, K. H.

    2013-11-01

    In this paper, we aim to address an important issue about the pseudopotential lattice Boltzmann (LB) model, which has attracted much attention as a mesoscopic model for simulating interfacial dynamics of complex fluids, but suffers from the problem that the surface tension cannot be tuned independently of the density ratio. In the literature, a multirange potential was devised to adjust the surface tension [Sbragaglia , Phys. Rev. EPLEEE81063-651X10.1103/PhysRevE.75.026702 75, 026702 (2007)]. However, it was recently found that the density ratio of the system will be changed when the multirange potential is employed to adjust the surface tension. An alternative approach is therefore proposed in the present work. The basic strategy is to add a source term to the LB equation so as to tune the surface tension of the pseudopotential LB model. The proposed approach can guarantee that the adjustment of the surface tension does not affect the mechanical stability condition of the pseudopotential LB model, and thus provides a separate control of the surface tension and the density ratio. Meanwhile, it still retains the mesoscopic feature and the computational simplicity of the pseudopotential LB model. Numerical simulations are carried out for stationary droplets, capillary waves, and droplet splashing on a thin liquid film. The numerical results demonstrate that the proposed approach is capable of achieving a tunable surface tension over a very wide range and can keep the density ratio unchanged when adjusting the surface tension.

  9. Tailoring the surface chemical bond states of the NbN films by doping Ag: Achieving hard hydrophobic surface

    NASA Astrophysics Data System (ADS)

    Ren, Ping; Zhang, Kan; Du, Suxuan; Meng, Qingnan; He, Xin; Wang, Shuo; Wen, Mao; Zheng, Weitao

    2017-06-01

    Robust hydrophobic surfaces based on ceramics capable of withstanding harsh conditions such as abrasion, erosion and high temperature, are required in a broad range of applications. The metal cations with coordinative saturation or low electronegativity are commonly chosen to achieve the intrinsically hydrophobic ceramic by reducing Lewis acidity, and thus the ceramic systems are limited. In this work, we present a different picture that robust hydrophobic surface with high hardness (≥20 GPa) can be fabricated through doping Ag atoms into intrinsically hydrophilic ceramic film NbN by reactive co-sputtering. The transition of wettability from hydrophilic to hydrophobic of Nb-Ag-N films induced by Ag doping results from the appearance of Ag2O groups on the films surfaces through self-oxidation, because Ag cations (Ag+) in Ag2O are the filled-shell (4d105S0) electronic structure with coordinative saturation that have no tendency to interact with water. The results show that surface Ag2O benefited for hydrophobicity comes from the solute Ag atoms rather than precipitate metal Ag, in which the more Ag atoms incorporated into Nb-sublattice are able to further improve the hydrophobicity, whereas the precipitation of Ag nanoclusters would worsen it. The present work opens a window for fabricating robust hydrophobic surface through tailoring surface chemical bond states by doping Ag into transition metal nitrides.

  10. Modeling and simulation of protein-surface interactions: achievements and challenges.

    PubMed

    Ozboyaci, Musa; Kokh, Daria B; Corni, Stefano; Wade, Rebecca C

    2016-01-01

    Understanding protein-inorganic surface interactions is central to the rational design of new tools in biomaterial sciences, nanobiotechnology and nanomedicine. Although a significant amount of experimental research on protein adsorption onto solid substrates has been reported, many aspects of the recognition and interaction mechanisms of biomolecules and inorganic surfaces are still unclear. Theoretical modeling and simulations provide complementary approaches for experimental studies, and they have been applied for exploring protein-surface binding mechanisms, the determinants of binding specificity towards different surfaces, as well as the thermodynamics and kinetics of adsorption. Although the general computational approaches employed to study the dynamics of proteins and materials are similar, the models and force-fields (FFs) used for describing the physical properties and interactions of material surfaces and biological molecules differ. In particular, FF and water models designed for use in biomolecular simulations are often not directly transferable to surface simulations and vice versa. The adsorption events span a wide range of time- and length-scales that vary from nanoseconds to days, and from nanometers to micrometers, respectively, rendering the use of multi-scale approaches unavoidable. Further, changes in the atomic structure of material surfaces that can lead to surface reconstruction, and in the structure of proteins that can result in complete denaturation of the adsorbed molecules, can create many intermediate structural and energetic states that complicate sampling. In this review, we address the challenges posed to theoretical and computational methods in achieving accurate descriptions of the physical, chemical and mechanical properties of protein-surface systems. In this context, we discuss the applicability of different modeling and simulation techniques ranging from quantum mechanics through all-atom molecular mechanics to coarse

  11. Cu-Cu direct bonding achieved by surface method at room temperature

    SciTech Connect

    Utsumi, Jun; Ichiyanagi, Yuko

    2014-02-20

    The metal bonding is a key technology in the processes for the microelectromechanical systems (MEMS) devices and the semiconductor devices to improve functionality and higher density integration. Strong adhesion between surfaces at the atomic level is crucial; however, it is difficult to achieve close bonding in such a system. Cu films were deposited on Si substrates by vacuum deposition, and then, two Cu films were bonded directly by means of surface activated bonding (SAB) at room temperature. The two Cu films, with the surface roughness Ra about 1.3nm, were bonded by using SAB at room temperature, however, the bonding strength was very weak in this method. In order to improve the bonding strength between the Cu films, samples were annealed at low temperatures, between 323 and 473 K, in air. As the result, the Cu-Cu bonding strength was 10 times higher than that of the original samples without annealing.

  12. Modified surface loading process for achieving improved performance of the quantum dot-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Liu, Feng; Jin, Zhongxiu; Zhu, Jun; Xu, Yafeng; Zhou, Li; Dai, Songyuan

    2016-06-01

    Achieving high surface coverage of the colloidal quantum dots (QDs) on TiO2 films has been challenging for quantum dot-sensitized solar cells (QDSCs). Herein, a general surface engineering approach was proposed to increase the loading of these QDs. It was found that S2- treatment/QD re-uptake process can significantly improve the attachment of the QDs on TiO2 films. Surface concentration of the QDs was improved by ∼60%, which in turn greatly enhances light absorption and decreases carrier recombination in QDSCs. Ensuing QDSCs with optimized QD loading exhibit a power conversion efficiency of 3.66%, 83% higher than those fabricated with standard procedures.

  13. Single peptide ligand-functionalized uniform hollow mesoporous silica nanoparticles achieving dual-targeting drug delivery to tumor cells and angiogenic blood vessel cells

    PubMed Central

    Liu, Yang; Chen, Qing; Xu, Ming; Guan, Guannan; Hu, Wen; Liang, Ying; Zhao, Xiuli; Qiao, Mingxi; Chen, Dawei; Liu, Hao

    2015-01-01

    Background The purpose of this study was to construct hollow mesoporous silica nanoparticles (HMSN) decorated with tLyp-1 peptide (tHMSN) for dual-targeting drug delivery to tumor cells and angiogenic blood vessel cells. Methods HMSN were synthesized de novo using a novel cationic surfactant-assisted selective etching strategy and were then modified with tLyp-1. Multiple methods, including transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, bicinchoninic acid assay, and nitrogen adsorption and desorption isotherms, were used to characterize the tHMSN. Doxorubicin were chosen as the model cargo, and the uptake of doxorubicin-loaded tHMSN into MDA-MB-231 cells and human umbilical vein endothelial cells (HUVECs), as models of tumor cells and tumor neovascular endothelial cells, respectively, were observed and detected by confocal laser scanning microscopy and flow cytometry. An in vitro pharmacodynamic study and a study of the mechanism via which the nanoparticles were endocytosed were also performed. Results HMSN with a highly uniform size and well oriented mesopores were synthesized. After tHMSN were characterized, enhanced uptake of the cargo carried by tHMSN into MDA-MB-231 cells and HUVECs compared with that of their unmodified counterparts was validated by confocal laser scanning microscopy and flow cytometry at the qualitative and quantitative levels, respectively. Further, the pharmacodynamic study suggested that, compared with their unmodified counterparts, doxorubicin-loaded tHMSN had an enhanced inhibitory effect on MDA-MB-231 cells and HUVECs in vitro. Finally, a preliminary study on the mechanism by which the nanoparticles were endocytosed indicated that the clathrin-mediated endocytosis pathway has a primary role in the transport of tHMSN into the cytoplasm. Conclusion tHMSN might serve as an effective active targeting nanocarrier strategy for anti-mammary cancer drug delivery. PMID:25834425

  14. Single peptide ligand-functionalized uniform hollow mesoporous silica nanoparticles achieving dual-targeting drug delivery to tumor cells and angiogenic blood vessel cells.

    PubMed

    Liu, Yang; Chen, Qing; Xu, Ming; Guan, Guannan; Hu, Wen; Liang, Ying; Zhao, Xiuli; Qiao, Mingxi; Chen, Dawei; Liu, Hao

    2015-01-01

    The purpose of this study was to construct hollow mesoporous silica nanoparticles (HMSN) decorated with tLyp-1 peptide (tHMSN) for dual-targeting drug delivery to tumor cells and angiogenic blood vessel cells. HMSN were synthesized de novo using a novel cationic surfactant-assisted selective etching strategy and were then modified with tLyp-1. Multiple methods, including transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, bicinchoninic acid assay, and nitrogen adsorption and desorption isotherms, were used to characterize the tHMSN. Doxorubicin were chosen as the model cargo, and the uptake of doxorubicin-loaded tHMSN into MDA-MB-231 cells and human umbilical vein endothelial cells (HUVECs), as models of tumor cells and tumor neovascular endothelial cells, respectively, were observed and detected by confocal laser scanning microscopy and flow cytometry. An in vitro pharmacodynamic study and a study of the mechanism via which the nanoparticles were endocytosed were also performed. HMSN with a highly uniform size and well oriented mesopores were synthesized. After tHMSN were characterized, enhanced uptake of the cargo carried by tHMSN into MDA-MB-231 cells and HUVECs compared with that of their unmodified counterparts was validated by confocal laser scanning microscopy and flow cytometry at the qualitative and quantitative levels, respectively. Further, the pharmacodynamic study suggested that, compared with their unmodified counterparts, doxorubicin-loaded tHMSN had an enhanced inhibitory effect on MDA-MB-231 cells and HUVECs in vitro. Finally, a preliminary study on the mechanism by which the nanoparticles were endocytosed indicated that the clathrin-mediated endocytosis pathway has a primary role in the transport of tHMSN into the cytoplasm. tHMSN might serve as an effective active targeting nanocarrier strategy for anti-mammary cancer drug delivery.

  15. Frobisher Bay, Baffin Island, Northwest Territories, Canada. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1970-01-29

    to the National Technical Information Service (NTIS). This technical report has been reviewed and is aonroved for ouhl i cati on. WAYNE IMCOLLOM,h...ADDRESS 12 REPORT ::ATE U 29 JAN 70 Air Weather Service (MAC) 13 1 6 S6ER OF PA2ES Scott AFB IL 62225 14 .ONITORIN2. AGENCY NAUME 8 ADDRESS(,e .I,fl- I...N/A N/A N/A to Aug 50 USAF ITAC JMA I4 0-64A (OL.) MAC- Al It .- li, PAT ROCSI G DIVISION Revised ETAC/USAF AIR WEATIE SERVICE (MAC) UNIFORM SUMMARY

  16. Formation of Uniform and High-Coverage Monolayer Colloidal Films of Midnanometer-Sized Gold Particles over the Entire Surfaces of 1.5-in. Substrates.

    PubMed

    Yanagida, Sayaka; Nishiyama, Satoko; Sakamoto, Kenji; Fudouzi, Hiroshi; Miki, Kazushi

    2017-09-26

    We report a simple and facile method for fabricating monolayer colloidal films of alkanethiol-capped gold nanoparticles (AuNPs) on glass substrates. The new method consists of two sequential sonication processes. The first sonication is performed to obtain a well-dispersed state of alkanethiol-capped AuNPs in hexane/acetone in the presence of a substrate. After additional static immersion in the colloidal solution for 5 min, the substrate is subjected to sonication in hexane. By using this method, we succeeded in forming uniform and stable assemblies of midnanometer-sized AuNPs (14, 34, and 67 nm in diameter) over the entire surface of 10-mm square glass substrates in a short processing time of less than 10 min. It was also demonstrated that this method can be applied to a 1.5-in. octagonal glass substrate. The mechanism of monolayer colloidal film formation was discussed based on scanning electron microscopy observations at each preparation step. We found that the second sonication was the key process for uniform and high-surface-coverage colloidal film formation of midnanometer-sized AuNPs. The second sonication promotes the migration of AuNPs on top of the monolayer in contact with the substrate surface, decreasing both the multilayer region and the bare surface area. Eventually, a nearly perfect monolayer colloidal film is formed.

  17. Achieving High Spatial Resolution Surface Plasmon Resonance Microscopy with Image Reconstruction.

    PubMed

    Yu, Hui; Shan, Xiaonan; Wang, Shaopeng; Tao, Nongjian

    2017-03-07

    Surface plasmon resonance microscopy (SPRM) is a powerful platform for biomedical imaging and molecular binding kinetics analysis. However, the spatial resolution of SPRM along the plasmon propagation direction (longitudinal) is determined by the decaying length of the plasmonic wave, which can be as large as tens of microns. Different methods have been proposed to improve the spatial resolution, but each at the expense of decreased sensitivity or temporal resolution. Here we present a method to achieve high spatial resolution SPRM based on deconvolution of complex field. The method does not require additional optical setup and improves the spatial resolution in the longitudinal direction. We applied the method to image nanoparticles and achieved close-to-diffraction limit resolution in both longitudinal and transverse directions.

  18. Incorporation of silver nanoparticles on the surface of orthodontic microimplants to achieve antimicrobial properties

    PubMed Central

    Venugopal, Adith; Muthuchamy, Nallal; Tejani, Harsh; Gopalan, Anantha-Iyengar; Lee, Kwang-Pill; Lee, Heon-Jin

    2017-01-01

    Objective Microbial aggregation around dental implants can lead to loss/loosening of the implants. This study was aimed at surface treating titanium microimplants with silver nanoparticles (AgNPs) to achieve antibacterial properties. Methods AgNP-modified titanium microimplants (Ti-nAg) were prepared using two methods. The first method involved coating the microimplants with regular AgNPs (Ti-AgNP) and the second involved coating them with a AgNP-coated biopolymer (Ti-BP-AgNP). The topologies, microstructures, and chemical compositions of the surfaces of the Ti-nAg were characterized by scanning electron microscopy (SEM) equipped with energy-dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). Disk diffusion tests using Streptococcus mutans, Streptococcus sanguinis, and Aggregatibacter actinomycetemcomitans were performed to test the antibacterial activity of the Ti-nAg microimplants. Results SEM revealed that only a meager amount of AgNPs was sparsely deposited on the Ti-AgNP surface with the first method, while a layer of AgNP-coated biopolymer extended along the Ti-BP-AgNP surface in the second method. The diameters of the coated nanoparticles were in the range of 10 to 30 nm. EDS revealed 1.05 atomic % of Ag on the surface of the Ti-AgNP and an astounding 21.2 atomic % on the surface of the Ti-BP-AgNP. XPS confirmed the metallic state of silver on the Ti-BP-AgNP surface. After 24 hours of incubation, clear zones of inhibition were seen around the Ti-BP-AgNP microimplants in all three test bacterial culture plates, whereas no antibacterial effect was observed with the Ti-AgNP microimplants. Conclusions Titanium microimplants modified with Ti-BP-AgNP exhibit excellent antibacterial properties, making them a promising implantable biomaterial. PMID:28127534

  19. AFM Studies on Liquid Superlubricity between Silica Surfaces Achieved with Surfactant Micelles.

    PubMed

    Li, Jinjin; Zhang, Chenhui; Cheng, Peng; Chen, Xinchun; Wang, Weiqi; Luo, Jianbin

    2016-06-07

    By using atomic force microscopy (AFM), we showed that the liquid superlubricity with a superlow friction coefficient of 0.0007 can be achieved between two silica surfaces lubricated by hexadecyltrimethylammonium bromide (C16TAB) solution. There exists a critical load that the lubrication state translates from superlow friction to high friction reversibly. To analyze the superlow friction mechanism and the factors influencing the critical load, we used AFM to measure the structure of adsorbed C16TAB molecules and the normal force between two silica surfaces. Experimental results indicate that the C16TAB molecules are firmly adsorbed on the two silica surfaces by electrostatic interaction, forming cylinder-like micelles. Meanwhile, the positively charged headgroups exposed to solution produce the hydration and double layer repulsion to bear the applied load. By controlling the concentration of C16TAB solution, it is confirmed that the critical load of superlow friction is determined by the maximal normal force produced by the hydration layer. Finally, the superlow friction mechanism was proposed that the adsorbed micellar layer forms the hydration layer, making the two friction surfaces be in the repulsive region and meanwhile providing excellent fluidity without adhesion between micelles.

  20. Review of Techniques to Achieve Optical Surface Cleanliness and Their Potential Application to Surgical Endoscopes

    PubMed Central

    Kreeft, Davey; Arkenbout, Ewout Aart; Henselmans, Paulus Wilhelmus Johannes; van Furth, Wouter R.; Breedveld, Paul

    2017-01-01

    A clear visualization of the operative field is of critical importance in endoscopic surgery. During surgery the endoscope lens can get fouled by body fluids (eg, blood), ground substance, rinsing fluid, bone dust, or smoke plumes, resulting in visual impairment. As a result, surgeons spend part of the procedure on intermittent cleaning of the endoscope lens. Current cleaning methods that rely on manual wiping or a lens irrigation system are still far from ideal, leading to longer procedure times, dirtying of the surgical site, and reduced visual acuity, potentially reducing patient safety. With the goal of finding a solution to these issues, a literature review was conducted to identify and categorize existing techniques capable of achieving optically clean surfaces, and to show which techniques can potentially be implemented in surgical practice. The review found that the most promising method for achieving surface cleanliness consists of a hybrid solution, namely, that of a hydrophilic or hydrophobic coating on the endoscope lens and the use of the existing lens irrigation system. PMID:28511635

  1. Color Uniformity in Navy Uniforms.

    DTIC Science & Technology

    1980-05-01

    realized in contracting with a specific trouser, skirt, shirt or blouse manufacturer. Uniform items are issued on the basis of size and not on a top...Blue 3346 Spec. No.: MIL-C-29147 End Item: Men’s Winter Shirt Method of Issue: Stock Item - DPSC Procured Optional - NAVRESSO Method of Dyeing: Standard...Polyester Color: Blue 3346 Spec. No.: MIL-C-87051 End Item: Women’s Winter Shirt (new) Method of Issue: Stock Item - DPSC Procured Method of Dyeing: Piece

  2. Design of Free-Standing Microstructured Conducting Polymer Films for Enhanced Particle Removal from Non-uniform Surfaces

    NASA Astrophysics Data System (ADS)

    Laster, Jennifer; Deom, Nicholas; Boudouris, Bryan; Beaudoin, Stephen

    Particle removal from surfaces is important for a wide range of industrial applications (e.g., microelectronics fabrication). One of the main forces of particle adhesion to a surface is the van der Waals attraction force, which will be the focus of this effort. The surface features of interacting bodies can play a controlling role in the adhesion of particles by increasing or decreasing the amount of mass within the range of strong van der Waals forces. In order to control these interactions, specific geometries can be designed in order to manipulate the micro- and nanostructure of a material, which can conform to the features of a corresponding substrate increasing the overall contact area between the two surfaces. In this work, microstructured films of the conducting polymer polypyrrole (PPy) were synthesized through template-assisted electropolymerization techniques. The removal of fluorescently-labeled polystyrene beads from aluminum surfaces of varying roughness was measured and compared for microstructured and flat PPy films. The microstructured films were found to have an overall increase in the amount of particles removed from the aluminum surfaces; this demonstrates the ability to manipulate particle adhesion through advanced nanostructured polymer templating.

  3. Investigation of the Effect of Material on Undamped Free Vibration of Cantilever Beams with Uniform Single Surface Crack

    NASA Astrophysics Data System (ADS)

    Mufazzal, Sameera; Muzakkir, S. M.; Zakir Jafri, Hasan

    2017-08-01

    Crack detection in structures is a critical area of research where the developments have been made out since decades. Various techniques are available for early identification and quantification of cracks to predict and prevent the unexpected sudden failure of structure and ensure uninterrupted service. Use of vibration analysis for detecting crack is one of the widely used techniques which offer lots of advantages over other like it is easier and less costly method and can be used for inaccessible components. The present work attempts to use modal analysis through FEA to investigate the effect of crack on natural frequency of vibration in beams of different materials, for three different crack location. From the result, it has been inferred that among Structural Steel (SS), Aluminium alloy (Al) and Gray Cast Iron (CI), the natural frequency is highest for Al beam and lowest for CI beam. Introduction of crack reduces the natural frequency of vibration, however, the effect of crack location on frequency is not uniform for different modes. Also, the trend is similar in beams of all the materials.

  4. Large-Area Optical Coatings with Uniform Thickness Grown by Surface Chemical Reactions for High-Power Laser Applications

    NASA Astrophysics Data System (ADS)

    Zaitsu, Shin-ichi; Motokoshi, Shinji; Jitsuno, Takahisa; Nakatsuka, Masahiro; Yamanaka, Tatsuhiko

    2002-01-01

    We prepared optical thin films using an atomic layer deposition (ALD) procedure in order to apply this coating method to optical components for high-power and large-scale lasers. Film thickness shows a proportional relationship to the number of operation cycles even in the case of room-temperature growth, and the distribution is uniform with a thickness error of less than 1% over an area of 240 mm diameter. We examined the laser damage thresholds of the films with 1 ns laser pulses at 1.064 μm. The highest thresholds (TiO2: 5 J/cm2, Al2O3: 5.2 J/cm2) are obtained in the amorphous films grown at low growth temperatures (25-50°C). Results from the analysis of film structure and composition, and measurement of optical absorption reveal that the decrease in laser damage threshold as the growth temperature rises is caused by the crystallization of films.

  5. Spatially Uniform Thin-Film Formation of Polymeric Organic Semiconductors on Lyophobic Gate Insulator Surfaces by Self-Assisted Flow-Coating.

    PubMed

    Bulgarevich, Kirill; Sakamoto, Kenji; Minari, Takeo; Yasuda, Takeshi; Miki, Kazushi

    2017-02-22

    Surface hydrophobization by self-assembled monolayer formation is a powerful technique for improving the performance of organic field-effect transistors (OFETs). However, organic thin-film formation on such a surface by solution processing often fails due to the repellent property of the surface against common organic solvents. Here, a scalable unidirectional coating technique that can solve this problem, named self-assisted flow-coating, is reported. Producing a specially designed lyophobic-lyophilic pattern on the lyophobic surface enables organic thin-film formation in the lyophobic surface areas by flow-coating. To demonstrate the usefulness of this technique, OFET arrays with an active layer of poly(2,5-bis(3-hexadecylthiophene-2-yl)thieno[3,2-b]thiophene) are fabricated. The ideal transfer curves without hysteresis behavior are obtained for all OFETs. The average field-effect hole mobility in the saturation regime is 0.273 and 0.221 cm(2)·V(-1)·s(-1) for the OFETs with the channels parallel and perpendicular to the flow-coating direction, respectively, and the device-to-device variation is less than 3% for each OFET set. Very small device-to-device variation is also obtained for the on-state current, threshold voltage, and subthreshold swing. These results indicate that the self-assisted flow-coating is a promising coating technique to form spatially uniform thin films of polymeric organic semiconductors on lyophobic gate insulator surfaces.

  6. Microstructure of oxide layers formed on zirconium alloy by air oxidation, uniform corrosion and fresh-green surface modification

    NASA Astrophysics Data System (ADS)

    Sawabe, Takashi; Sonoda, Takeshi; Furuya, Masahiro; Kitajima, Shoichi; Kinoshita, Motoyasu; Tokiwai, Moriyasu

    2011-12-01

    Cladding materials with superior corrosion resistance and anti-hydrogen pickup have been developed for high burnup nuclear fuel. We have suggested a surface modification of the cladding materials for this purpose and invented a new surface modification method "Fresh-Green". The Fresh-Green treatment oxidizes and carbonizes a material surface in the same process. Zircaloy-2 with the Fresh-Green treatment showed the improvement of corrosion resistance in autoclave tests. In order to investigate the effect of surface modifications on the corrosion resistance, a synchrotron radiation experiment and a TEM observation were performed on different oxide layers formed on Zircaloy-2. The oxide layers were formed by air-oxidation, an autoclave test and the Fresh-Green treatment. Crystal structures of all the samples were transformed as Zr > Zr 3O > tetragonal ZrO 2 > monoclinic ZrO 2 from the matrix to the surface. Columnar grains of monoclinic zirconia were arranged unidirectionally in the Fresh-Green oxide layer treated at a low temperature. Diffusing capacity for oxygen influenced the crystal structure of the oxide layers.

  7. All Inkjet-Printed Metal-Oxide Thin-Film Transistor Array with Good Stability and Uniformity Using Surface-Energy Patterns.

    PubMed

    Li, Yuzhi; Lan, Linfeng; Sun, Sheng; Lin, Zhenguo; Gao, Peixiong; Song, Wei; Song, Erlong; Zhang, Peng; Peng, Junbiao

    2017-03-08

    An array of inkjet-printed metal-oxide thin-film transistors (TFTs) is demonstrated for the first time with the assistance of surface-energy patterns prepared by printing pure solvent to etch the ultrathin hydrophobic layer. The surface-energy patterns not only restrained the spreading of inks but also provided a facile way to regulate the morphology of metal oxide films without optimizing ink formulation. The fully printed InGaO TFT devices in the array exhibited excellent electron transport characteristics with a maximum mobility of 11.7 cm(2) V(-1) s(-1), negligible hysteresis, good uniformity, and good stability under bias stress. The new route lights a general way toward fully inkjet-printed metal-oxide TFT arrays.

  8. Toward Uniformity in Exchange Communication

    ERIC Educational Resources Information Center

    Shinn, Isabella

    1972-01-01

    Instant communication, characterized by brevity, should be the practice of exchange librarians trading titles on the international level. Guidelines for a multilingual, many-purpose form letter, which could achieve uniformity, are presented. (14 references) (Author/SJ)

  9. Sealable stagnation flow geometries for the uniform deposition of materials and heat

    DOEpatents

    McCarty, Kevin F.; Kee, Robert J.; Lutz, Andrew E.; Meeks, Ellen

    2001-01-01

    The present invention employs a constrained stagnation flow geometry apparatus to achieve the uniform deposition of materials or heat. The present invention maximizes uniform fluxes of reactant gases to flat surfaces while minimizing the use of reagents and finite dimension edge effects. This results, among other things, in large area continuous films that are uniform in thickness, composition and structure which is important in chemical vapor deposition processes such as would be used for the fabrication of semiconductors.

  10. F. E. Warren AFB, Cheyenne, Wyoming. Revised uniform summary of surface weather observations (RUSSWO). Parts A-F. Final report

    SciTech Connect

    Not Available

    1980-05-01

    This report is a six-part statistical summary of surface weather observations for F E Warren AFB, Cheyenne, Wyoming. It contains the following parts: (A) Weather Conditions; Atmospheric Phenomena; (B) Precipitation, Snowfall and Snow Depth (daily amounts and extreme values); (C) Surface winds; (D) Ceiling Versus Visibility; Sky Cover; (E) Psychrometric Summaries (daily maximum and minimum temperatures, extreme maximum and minimum temperatures, psychrometric summary of wet-bulb temperature depression versus dry-bulb temperature, means and standard deviations of dry-bulb, wet-bulb and dew-point temperatures and relative humidity); and (F) Pressure Summary (means, standard, deviations, and observation counts of station pressure and sea-level pressure). Data in this report are presented in tabular form, in most cases in percentage frequency of occurrence or cumulative percentage frequency of occurrence tables.

  11. Stallion Site, San Marcial, New Mexico. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A, C through F.

    DTIC Science & Technology

    1975-02-21

    distribution of this report to the public at large, or by vDC to the National Technical Information Service (IS). This technical report has been...UNCLASSIFED USA60/0.W0O3S Lmmhmhhhh 11111 . ~2.0 1111112 11 1. 1 . MICROCOPY RESOLUTION TEST CHART NATIONAL BUREAU OF STANDARDS-1%63-A Camera Operator use...PROCESSIGSHEET DTI 70 OCT DATA PROCESSING BRANCH USAFETAC Air Weather Service ( MAC) REVISED UN IFORM SUMMARY OF SURFACE WEATHER OBSEVATIONS STALLION

  12. Ramstein AB (Germany, F.R.) Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    DTIC Science & Technology

    1985-05-01

    addition of a suffix zero; or, in cases where there is no designated WMO number, a 5-digit number created in agreement with WMO rules, plus a sixth...HOURLY OBSERVATIONS) SURFACE WINDS l 3Mi»3 »MSTCH «J Si^WtMY STATION N^MC 7H-93 ILL ri£ ftTH £3 *JG ttOUi* (LIT.) SPEED (KNTS) DIR. 1 -3

  13. Ubon RTAFB, Ubon Ratchathani, Thailand. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1971-03-02

    Summary of Surface Weather Final rept. Observations (RUSSWO)- Fina _ __ept. JBODN RTARB, UBN RATcHATHANI, THAILAND . PERFORMING ORG. REPORT NUMBER 7...1 1 13’:1 "IN LISAF CEILING VERSUS VISIBILITY 4 1 rt ,’LkI"F R -f, v I ’ / AL 41017 ,. N RAIC "’AI-IAK[ HAIIU.IN KTAH1 66-6 " ’ (t PERCENTAGE FREQUENCY

  14. Photonic activation of disulfide bridges achieves oriented protein immobilization on biosensor surfaces.

    PubMed

    Neves-Petersen, Maria Teresa; Snabe, Torben; Klitgaard, Søren; Duroux, Meg; Petersen, Steffen B

    2006-02-01

    Photonic induced immobilization is a novel technology that results in spatially oriented and spatially localized covalent coupling of biomolecules onto thiol-reactive surfaces. Immobilization using this technology has been achieved for a wide selection of proteins, such as hydrolytic enzymes (lipases/esterases, lysozyme), proteases (human plasminogen), alkaline phosphatase, immunoglobulins' Fab fragment (e.g., antibody against PSA [prostate specific antigen]), Major Histocompability Complex class I protein, pepsin, and trypsin. The reaction mechanism behind the reported new technology involves "photonic activation of disulfide bridges," i.e., light-induced breakage of disulfide bridges in proteins upon UV illumination of nearby aromatic amino acids, resulting in the formation of free, reactive thiol groups that will form covalent bonds with thiol-reactive surfaces (see Fig. 1). Interestingly, the spatial proximity of aromatic residues and disulfide bridges in proteins has been preserved throughout molecular evolution. The new photonic-induced method for immobilization of proteins preserves the native structural and functional properties of the immobilized protein, avoiding the use of one or more chemical/thermal steps. This technology allows for the creation of spatially oriented as well as spatially defined multiprotein/DNA high-density sensor arrays with spot size of 1 microm or less, and has clear potential for biomedical, bioelectronic, nanotechnology, and therapeutic applications.

  15. Poking Holes and Cutting Corners to Achieve Clifford Gates with the Surface Code

    NASA Astrophysics Data System (ADS)

    Brown, Benjamin J.; Laubscher, Katharina; Kesselring, Markus S.; Wootton, James R.

    2017-04-01

    The surface code is currently the leading proposal to achieve fault-tolerant quantum computation. Among its strengths are the plethora of known ways in which fault-tolerant Clifford operations can be performed, namely, by deforming the topology of the surface, by the fusion and splitting of codes, and even by braiding engineered Majorana modes using twist defects. Here, we present a unified framework to describe these methods, which can be used to better compare different schemes and to facilitate the design of hybrid schemes. Our unification includes the identification of twist defects with the corners of the planar code. This identification enables us to perform single-qubit Clifford gates by exchanging the corners of the planar code via code deformation. We analyze ways in which different schemes can be combined and propose a new logical encoding. We also show how all of the Clifford gates can be implemented with the planar code, without loss of distance, using code deformations, thus offering an attractive alternative to ancilla-mediated schemes to complete the Clifford group with lattice surgery.

  16. New evidence for TiO2 uniform surfaces leading to complete bacterial reduction in the dark: critical issues.

    PubMed

    Nesic, Jelena; Rtimi, Sami; Laub, Danièle; Roglic, Goran M; Pulgarin, Cesar; Kiwi, John

    2014-11-01

    This study presents new evidence for the events leading to Escherichia coli reduction in the absence of light irradiation on TiO2-polyester (from now on TiO2-PES. By transmission electron microscopy (TEM) the diffusion of TiO2 NP's aggregates with the E. coli outer lipo-polyssacharide (LPS) layer is shown to be a prerequisite for the loss of bacterial cultivability. Within 30 min in the dark the TiO2 aggregates interact with E. coli cell wall leading within 120 min to the complete loss of bacterial cultivability on a TiO2-PES 5% TiO2 sample. The bacterial reduction was observed to increase with a higher TiO2 loading on the PES up to 5%. Bacterial disinfection on TiO2-PES in the dark was slower compared to the runs under low intensity simulated sunlight light irradiation. The interaction between the TiO2 aggregates and the E. coli cell wall is discussed in terms of the competition between the TiO2 units collapsing to form TiO2-aggregates at a physiologic pH-value followed by the electrostatic interaction with the bacteria surface. TiO2-PES samples were able to carry repetitive bacterial inactivation. This presents a potential for practical applications. X-ray photoelectron spectroscopy (XPS) evidence was found for the reduction of Ti4+ to Ti3+ contributing to redox interactions between TiO2-PES and the bacterial cell wall. Insight is provided into the mechanism of interaction between the E. coli cell wall and TiO2 NP's. The properties of the TiO2-PES surface like percentage atomic concentration, TiO2-loading, optical absorption, surface charge and crystallographic phases are reported in this study.

  17. Robins AFB, Warner Robins, Georgia. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    DTIC Science & Technology

    1979-08-31

    73 - FED 79 POR FROM DAILY OBS: MAIR 49 - FEB 79 - AUG 3 11979- j FEDERAL BUILDING ASHEVILLE, N. C . - t~ 10 02 057j$9.tO J" *~-X* 33,... *,i 7...IZY WOflOS ( C oiliu ove.’o old. It . coory and lIdentify by block Ooosb.r)- *RUSSWO Daily temperature Atmospheric pressure Snowfall Extreme Snow depth...Phenomena; (8) Precipitation, Snowfall and Snow Depth (daily amounts and extreme values); ( C ) Surface winds; (D) Ceiling Versus Visibility; Sky Cover; (E

  18. Fort Sill AAF, Lawton, Oklahoma. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    DTIC Science & Technology

    1979-09-19

    below: Thunderstorms - All reported occurrences of thunderstorm, tornado , and waterspout. Rain and, or arizzle - All liquid precipitatiou, falling to...0.8-5 (OL.A) PEIOUS EIhION$ Of THtS FORM ARE oSIOo1ft l7 ,I GLOBA L CLIMA TOL~rY LIRANCH AIR’ SFT SURFACE WINDS |, R ETH ER SERVIC/Ac PERCENTAGE...34_ - I --, . Ii.uii- -.1...... .... .i. II I _____7_- II____ _____ _______ __ __~ __ . a L GLOLl, L CLIMA ",Y BANCH LSAF, T^4- PSYCHROMETRIC SUMMARY AIR

  19. Travis Air Force Base, California, Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1983-12-19

    AL tL70A TO ANCI INDHZ TAC SURFACE WINDS .-FAT"’ SEPIC ’/"AC PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) S TL SSTATI...FROM DAILY OBSERVATIONS! TEMP FE I 6 MAR API? MAI JUN JUt AUG SEP oC, NOV DC ANNIIA, 7.. .2. . 2 9 - ,1.0 .c. .2. .9 .,.. 5 - o .1 .6 3.9 4.2 3.1...millibars. Provided below is a scale to convert station pressure values in inches of mercury or millibars to pressure- altitude in 1000’s of feet. This scale

  20. Model for the ultrasound reflection from micro-beads and cells distributed in layers on a uniform surface

    NASA Astrophysics Data System (ADS)

    Couture, O.; Cherin, E.; Foster, F. S.

    2007-07-01

    A model predicting the reflection of ultrasound from multiple layers of small scattering spheres is developed. Predictions of the reflection coefficient, which takes into account the interferences between the different sphere layers, are compared to measurements performed in the 10-80 MHz and 15-35 MHz frequency range with layers of glass beads and spherical acute myeloid leukemia (AML) cells, respectively. For both types of scatterers, the reflection coefficient increases as a function of their density on the surface for less than three superimposed layers, at which point it saturates at 0.38 for glass beads and 0.02 for AML cells. Above three layers, oscillations of the reflection coefficient due to constructive or destructive interference between layers are observed experimentally and are accurately predicted by the model. The use of such a model could lead to a better understanding of the structures observed in layered tissue images.

  1. Wright-Patterson AFB, Dayton, Ohio. Revised Uniform Summary of Surface Weather Observations. (RUSSWO). Parts A-F

    DTIC Science & Technology

    1980-02-29

    RACH A FLTAC SURFACE WINDS AP"’? FATHU SEPIC >/1C PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) i 4, PIGHT-PATFRSON -8 0H...00.0100.0 Z 200 b3. 87.6 92.4 96.2 97.8 98.9 99.3 99.8 99.9 99.9 00 .i _L0.O30.___D. o 0 87. 92. 96.2 97.8 98.9 99.3 99.8 99.9 99.9 oc000. DC . 00 . TOTAL...FOR THE TOTAL SKY COVER. CLEAR WAS CONVERTED TO 0/10 SCATTERED WAS CONVERTED TO 3/10 131ROKEN WAS CONVERTED TO 9/10 6 OVERCAST WAS CONVERTED TO 10/10

  2. Ft Nelson, Muskwa Apt, British Columbia, Canada. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    DTIC Science & Technology

    1972-01-17

    OF OBSERVATIONS U SAFE TA C 0850 a PRFOU I )󈧄 ) 3M f.,T, . Pr! f SIt Is~r ’I V IS I, T .I0,U 1, ,,,r SURFACE WINDS 2 .,14 -EAT r’L L vICFI/ ’C...PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) P, T LLb~ 5. L T 1o SSSTATIN"IO N NNA - E sWOT . ALL ,F.ATHI ") 0 0 , 00CLASS...6000 & 3M e -0 1 40.2 j.Z 00,2 6091 60.2 60.6 v00 ,1 60.6 60,9 60 .6 .0 01.r .(.1 01.6 goo 11 9000 f% qj~ a54 III f-j Ij~ A6 If ~ f, 0 -- 2 %I g 6

  3. Davison AAF, Ft. Belvoir Virginia. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    DTIC Science & Technology

    1980-12-08

    8.21 9.99 6.6 2.67 1.39 61.80 830 2.7 1.4 4.9 3.7: 2.6S MEAN 3.00, 2.88 5.691 3.01t 3.69 3.63 3,68 4.69. .. 17 3.9L .3,313 .,55 S.D. l, 82 ’ 1.76 1.28...SURFACE WINDS AIR WEATHER SERVICE/MAC PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) � -DAVISON AAF/FT RELVOIP VA b9 -70.71...OBSERVATIONS) . yj8 AVISON AAF/FT RELVOIR VA b9 -70.73-80 .F,3 STATION STATION NAMS YKARS MONTH ALL IWEATHE 8:- 0 CLASS HOURS IL.S.T. I CONDITION SPEED MEAN

  4. Enhanced oral bioavailability of acetylpuerarin by poly(lactide-co-glycolide) nanoparticles optimized using uniform design combined with response surface methodology

    PubMed Central

    Sun, Deqing; Xue, Aiying; Zhang, Bin; Xue, Xia; Zhang, Jie; Liu, Wenjie

    2016-01-01

    Acetylpuerarin (AP), an acetylated derivative of puerarin, shows brain-protective effects in animals. However, AP has low oral bioavailability because of its poor water solubility. The objective of this study was to design and develop poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) to enhance the oral bioavailability of AP. The NPs were prepared using a solvent diffusion method optimized via uniform design (UD) combined with response surface methodology (RSM) and characterized by their morphology, particle size, zeta (ζ)-potential, encapsulation efficiency (EE), drug loading (DL), and in vitro drug release. A pharmacokinetic study was conducted in Wistar rats administered a single oral dose of 30 mg/kg AP. The optimized NPs were spherical and uniform in shape, with an average particle size of 145.0 nm, a polydispersity index (PI) of 0.153, and a ζ-potential of −14.81 mV. The release of AP from the PLGA NPs showed an initial burst release followed by a sustained release, following Higuchi’s model. The EE and DL determined in the experiments were 90.51% and 17.07%, respectively. The area under the plasma concentration-time curve (AUC0−∞) of AP-PLGA-NPs was 6,175.66±350.31 h ng/mL, which was 2.75 times greater than that obtained from an AP suspension. This study showed that PLGA NPs can significantly enhance the oral bioavailability of AP. PMID:27382256

  5. Enhanced oral bioavailability of acetylpuerarin by poly(lactide-co-glycolide) nanoparticles optimized using uniform design combined with response surface methodology.

    PubMed

    Sun, Deqing; Xue, Aiying; Zhang, Bin; Xue, Xia; Zhang, Jie; Liu, Wenjie

    2016-01-01

    Acetylpuerarin (AP), an acetylated derivative of puerarin, shows brain-protective effects in animals. However, AP has low oral bioavailability because of its poor water solubility. The objective of this study was to design and develop poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs) to enhance the oral bioavailability of AP. The NPs were prepared using a solvent diffusion method optimized via uniform design (UD) combined with response surface methodology (RSM) and characterized by their morphology, particle size, zeta (ζ)-potential, encapsulation efficiency (EE), drug loading (DL), and in vitro drug release. A pharmacokinetic study was conducted in Wistar rats administered a single oral dose of 30 mg/kg AP. The optimized NPs were spherical and uniform in shape, with an average particle size of 145.0 nm, a polydispersity index (PI) of 0.153, and a ζ-potential of -14.81 mV. The release of AP from the PLGA NPs showed an initial burst release followed by a sustained release, following Higuchi's model. The EE and DL determined in the experiments were 90.51% and 17.07%, respectively. The area under the plasma concentration-time curve (AUC0-∞) of AP-PLGA-NPs was 6,175.66±350.31 h ng/mL, which was 2.75 times greater than that obtained from an AP suspension. This study showed that PLGA NPs can significantly enhance the oral bioavailability of AP.

  6. Long-Life Nickel-Rich Layered Oxide Cathodes with a Uniform Li2ZrO3 Surface Coating for Lithium-Ion Batteries.

    PubMed

    Song, Bohang; Li, Wangda; Oh, Seung-Min; Manthiram, Arumugam

    2017-03-22

    As nickel-rich layered oxide cathodes start to attract worldwide interest for the next-generation lithium-ion batteries, their long-term cyclability in full cells remains a challenge for electric vehicles. Here we report a long-life Ni-rich layered oxide cathode (LiNi0.7Co0.15Mn0.15O2) with a uniform surface coating of the cathode particles with Li2ZrO3. A pouch-type full cell fabricated with the Li2ZrO3-coated cathode and a graphite anode displays 73.3% capacity retention after 1500 cycles at a C/3 rate. The Li2ZrO3 coating has been optimized by a systematic study with different synthesis approaches, annealing temperatures, and coating amounts. The complex relationship among the coating conditions, uniformity, and morphology of the coating layer and their impacts on the electrochemical properties are discussed in detail.

  7. Surface-enhanced Raman imaging of red blood cell membrane with highly uniform active substrates obtained using block copolymers self-assembly

    NASA Astrophysics Data System (ADS)

    Zito, Gianluigi; Malafronte, Anna; Dochshanov, Alden; Rusciano, Giulia; Auriemma, Finizia; Pesce, Giuseppe; De Rosa, Claudio; Sasso, Antonio

    2013-05-01

    In this communication, we discuss the application of ordered, ultrahigh-density templates of nano-textured Ag-particles obtained by self-assembling of inorganic-containing polystyrene-block-poly(4-vinylpyridine) copolymer (PS-b-P4VP) micelles, for the spectroscopic surface-enhanced Raman imaging in-vitro of red blood cells (RBCs) and its capability to identify the vibrational fingerprint of the plasma membrane of the cell physisorbed to the SERS substrate. Hexagonal arrays of PS-b-P4VP micelles, with selective inclusion of Ag nanoparticles (NPs) in the polar core, prepared by in situ reduction of a suitable precursor, are obtained by polymer self-assembly upon fast solvent evaporation during spin coating on the supporting substrate. UV irradiation and/or plasma oxygen treatment remove the polymer matrix leaving immobilized nano-islands of Ag-NPs. Such a kind of SERS-active substrate consists of a reproducible and uniform twodimensional hexagonal array of silver clusters with a diameter ranging from 25 to 30 nm (single particles having typically diameters of 5 nm) and nano-island gap distances of the order of 5-8 nm on silicon and 15 nm on glass , while giving rise to high enhancement factors and addressing the issue of SERS reproducibility. The basic substrate supporting the plasmonic coating used in this work is either of silicon or glass. This last allows working in back scattering configuration permitting real time monitoring, via microscopy, of the RBCs on which Raman measurements are being carried out. The template is thus applied for surface-enhanced Raman analysis of the red blood cell (RBC) membrane in confocal micro-Raman configuration demonstrating to have SERS imaging potential thanks to the uniformity of the nano-textured substrate. The first experimental evidence of SERS imaging of a red blood cell membrane in-vitro is demonstrated.

  8. Intercomparison of methods of coupling between convection and large‐scale circulation: 1. Comparison over uniform surface conditions

    PubMed Central

    Plant, R. S.; Woolnough, S. J.; Sessions, S.; Herman, M. J.; Sobel, A.; Wang, S.; Kim, D.; Cheng, A.; Bellon, G.; Peyrille, P.; Ferry, F.; Siebesma, P.; van Ulft, L.

    2015-01-01

    Abstract As part of an international intercomparison project, a set of single‐column models (SCMs) and cloud‐resolving models (CRMs) are run under the weak‐temperature gradient (WTG) method and the damped gravity wave (DGW) method. For each model, the implementation of the WTG or DGW method involves a simulated column which is coupled to a reference state defined with profiles obtained from the same model in radiative‐convective equilibrium. The simulated column has the same surface conditions as the reference state and is initialized with profiles from the reference state. We performed systematic comparison of the behavior of different models under a consistent implementation of the WTG method and the DGW method and systematic comparison of the WTG and DGW methods in models with different physics and numerics. CRMs and SCMs produce a variety of behaviors under both WTG and DGW methods. Some of the models reproduce the reference state while others sustain a large‐scale circulation which results in either substantially lower or higher precipitation compared to the value of the reference state. CRMs show a fairly linear relationship between precipitation and circulation strength. SCMs display a wider range of behaviors than CRMs. Some SCMs under the WTG method produce zero precipitation. Within an individual SCM, a DGW simulation and a corresponding WTG simulation can produce different signed circulation. When initialized with a dry troposphere, DGW simulations always result in a precipitating equilibrium state. The greatest sensitivities to the initial moisture conditions occur for multiple stable equilibria in some WTG simulations, corresponding to either a dry equilibrium state when initialized as dry or a precipitating equilibrium state when initialized as moist. Multiple equilibria are seen in more WTG simulations for higher SST. In some models, the existence of multiple equilibria is sensitive to some parameters in the WTG calculations. PMID:27642500

  9. Intercomparison of methods of coupling between convection and large-scale circulation. 1. Comparison over uniform surface conditions

    SciTech Connect

    Daleu, C. L.; Plant, R. S.; Woolnough, S. J.; Sessions, S.; Herman, M. J.; Sobel, A.; Wang, S.; Kim, D.; Cheng, A.; Bellon, G.; Peyrille, P.; Ferry, F.; Siebesma, P.; van Ulft, L.

    2015-10-24

    Here, as part of an international intercomparison project, a set of single-column models (SCMs) and cloud-resolving models (CRMs) are run under the weak-temperature gradient (WTG) method and the damped gravity wave (DGW) method. For each model, the implementation of the WTG or DGW method involves a simulated column which is coupled to a reference state defined with profiles obtained from the same model in radiative-convective equilibrium. The simulated column has the same surface conditions as the reference state and is initialized with profiles from the reference state. We performed systematic comparison of the behavior of different models under a consistent implementation of the WTG method and the DGW method and systematic comparison of the WTG and DGW methods in models with different physics and numerics. CRMs and SCMs produce a variety of behaviors under both WTG and DGW methods. Some of the models reproduce the reference state while others sustain a large-scale circulation which results in either substantially lower or higher precipitation compared to the value of the reference state. CRMs show a fairly linear relationship between precipitation and circulation strength. SCMs display a wider range of behaviors than CRMs. Some SCMs under the WTG method produce zero precipitation. Within an individual SCM, a DGW simulation and a corresponding WTG simulation can produce different signed circulation. When initialized with a dry troposphere, DGW simulations always result in a precipitating equilibrium state. The greatest sensitivities to the initial moisture conditions occur for multiple stable equilibria in some WTG simulations, corresponding to either a dry equilibrium state when initialized as dry or a precipitating equilibrium state when initialized as moist. Multiple equilibria are seen in more WTG simulations for higher SST. In some models, the existence of multiple equilibria is sensitive to some parameters in the WTG calculations.

  10. Intercomparison of methods of coupling between convection and large-scale circulation. 1. Comparison over uniform surface conditions

    DOE PAGES

    Daleu, C. L.; Plant, R. S.; Woolnough, S. J.; ...

    2015-10-24

    Here, as part of an international intercomparison project, a set of single-column models (SCMs) and cloud-resolving models (CRMs) are run under the weak-temperature gradient (WTG) method and the damped gravity wave (DGW) method. For each model, the implementation of the WTG or DGW method involves a simulated column which is coupled to a reference state defined with profiles obtained from the same model in radiative-convective equilibrium. The simulated column has the same surface conditions as the reference state and is initialized with profiles from the reference state. We performed systematic comparison of the behavior of different models under a consistentmore » implementation of the WTG method and the DGW method and systematic comparison of the WTG and DGW methods in models with different physics and numerics. CRMs and SCMs produce a variety of behaviors under both WTG and DGW methods. Some of the models reproduce the reference state while others sustain a large-scale circulation which results in either substantially lower or higher precipitation compared to the value of the reference state. CRMs show a fairly linear relationship between precipitation and circulation strength. SCMs display a wider range of behaviors than CRMs. Some SCMs under the WTG method produce zero precipitation. Within an individual SCM, a DGW simulation and a corresponding WTG simulation can produce different signed circulation. When initialized with a dry troposphere, DGW simulations always result in a precipitating equilibrium state. The greatest sensitivities to the initial moisture conditions occur for multiple stable equilibria in some WTG simulations, corresponding to either a dry equilibrium state when initialized as dry or a precipitating equilibrium state when initialized as moist. Multiple equilibria are seen in more WTG simulations for higher SST. In some models, the existence of multiple equilibria is sensitive to some parameters in the WTG calculations.« less

  11. Intercomparison of methods of coupling between convection and large-scale circulation: 1. Comparison over uniform surface conditions.

    PubMed

    Daleu, C L; Plant, R S; Woolnough, S J; Sessions, S; Herman, M J; Sobel, A; Wang, S; Kim, D; Cheng, A; Bellon, G; Peyrille, P; Ferry, F; Siebesma, P; van Ulft, L

    2015-12-01

    As part of an international intercomparison project, a set of single-column models (SCMs) and cloud-resolving models (CRMs) are run under the weak-temperature gradient (WTG) method and the damped gravity wave (DGW) method. For each model, the implementation of the WTG or DGW method involves a simulated column which is coupled to a reference state defined with profiles obtained from the same model in radiative-convective equilibrium. The simulated column has the same surface conditions as the reference state and is initialized with profiles from the reference state. We performed systematic comparison of the behavior of different models under a consistent implementation of the WTG method and the DGW method and systematic comparison of the WTG and DGW methods in models with different physics and numerics. CRMs and SCMs produce a variety of behaviors under both WTG and DGW methods. Some of the models reproduce the reference state while others sustain a large-scale circulation which results in either substantially lower or higher precipitation compared to the value of the reference state. CRMs show a fairly linear relationship between precipitation and circulation strength. SCMs display a wider range of behaviors than CRMs. Some SCMs under the WTG method produce zero precipitation. Within an individual SCM, a DGW simulation and a corresponding WTG simulation can produce different signed circulation. When initialized with a dry troposphere, DGW simulations always result in a precipitating equilibrium state. The greatest sensitivities to the initial moisture conditions occur for multiple stable equilibria in some WTG simulations, corresponding to either a dry equilibrium state when initialized as dry or a precipitating equilibrium state when initialized as moist. Multiple equilibria are seen in more WTG simulations for higher SST. In some models, the existence of multiple equilibria is sensitive to some parameters in the WTG calculations.

  12. Intercomparison of methods of coupling between convection and large-scale circulation: 1. Comparison over uniform surface conditions

    NASA Astrophysics Data System (ADS)

    Daleu, C. L.; Plant, R. S.; Woolnough, S. J.; Sessions, S.; Herman, M. J.; Sobel, A.; Wang, S.; Kim, D.; Cheng, A.; Bellon, G.; Peyrille, P.; Ferry, F.; Siebesma, P.; van Ulft, L.

    2015-12-01

    As part of an international intercomparison project, a set of single-column models (SCMs) and cloud-resolving models (CRMs) are run under the weak-temperature gradient (WTG) method and the damped gravity wave (DGW) method. For each model, the implementation of the WTG or DGW method involves a simulated column which is coupled to a reference state defined with profiles obtained from the same model in radiative-convective equilibrium. The simulated column has the same surface conditions as the reference state and is initialized with profiles from the reference state. We performed systematic comparison of the behavior of different models under a consistent implementation of the WTG method and the DGW method and systematic comparison of the WTG and DGW methods in models with different physics and numerics. CRMs and SCMs produce a variety of behaviors under both WTG and DGW methods. Some of the models reproduce the reference state while others sustain a large-scale circulation which results in either substantially lower or higher precipitation compared to the value of the reference state. CRMs show a fairly linear relationship between precipitation and circulation strength. SCMs display a wider range of behaviors than CRMs. Some SCMs under the WTG method produce zero precipitation. Within an individual SCM, a DGW simulation and a corresponding WTG simulation can produce different signed circulation. When initialized with a dry troposphere, DGW simulations always result in a precipitating equilibrium state. The greatest sensitivities to the initial moisture conditions occur for multiple stable equilibria in some WTG simulations, corresponding to either a dry equilibrium state when initialized as dry or a precipitating equilibrium state when initialized as moist. Multiple equilibria are seen in more WTG simulations for higher SST. In some models, the existence of multiple equilibria is sensitive to some parameters in the WTG calculations.

  13. Polyaspartamide derivative nanoparticles with tunable surface charge achieve highly efficient cellular uptake and low cytotoxicity.

    PubMed

    Xu, Min; Zhao, Yuefang; Feng, Min

    2012-08-07

    Cationic nanocarrier mediated intracellular therapeutic agent delivery acts as a double-edged sword: the carriers promote cellular uptake, but interact nonspecifically and strongly with negatively charged endogenic proteins and cell membranes, which results in aggregates and high cytotoxicity. The present study was aimed at exploring zwitterionic polyaspartamide derivative nanoparticles for efficient intracellular delivery with low cytotoxicity. Poly(aspartic acid) partially grafted tetraethylenepentamine (PASP-pg-TEPA) with different isoelectric points (IEPs) was synthesized. The PASP-pg-TEPA formed zwitterionic nanoparticles with an irregular core and a well-defined shell structure in aqueous medium. Their particle size decreased from about 300 to 80 nm with an increase of the IEP from 7.5 to 9.1. The surface charge of the PASP-pg-TEPA nanoparticles could be tuned from positive to negative with a change of the pH of the medium. The nanoparticles with an IEP above 8.5 exhibited good stability under simulated physiological conditions. It was noted that the zwitterionic PASP-pg-TEPA nanoparticles displayed highly efficient cellular uptake in HeLa cells (approximately 99%) in serum-containing medium and did not adversely affect the cell viability at concentrations up to 1 mg/mL. Furthermore, thermodynamic analysis using isothermal titration calorimetry provided direct evidence that these zwitterionic nanoparticles had low binding affinities for serum protein. Therefore, the zwitterionic PASP-pg-TEPA nanoparticles could overcome limitations of cationic nanocarriers and achieve efficient intracellular delivery with low cytotoxicity.

  14. Effect of non-isothermal deposition on surface morphology and microstructure of uniform molten aluminum alloy droplets applied to three-dimensional printing

    NASA Astrophysics Data System (ADS)

    Zuo, Han-song; Li, He-jun; Qi, Le-hua; Luo, Jun; Zhong, Song-yi; Wu, Yao-feng

    2015-01-01

    Non-isothermal deposition of uniform molten droplets as basic building blocks has a great influence on the geometric profile and microstructure of metallic components fabricated by the drop-based three-dimensional (3D) printing technology. In this paper, the thermal and dynamic behaviors of molten aluminum droplets during non-isothermal deposition were studied numerically and experimentally. The result shows that local solidification and interfacial re-melting occur during the initial period of non-isothermal deposition. The re-melting in microseconds depends greatly on the impacting droplet temperature, the deposition surface temperature, and the thermal contact resistance. Further, the coupling action of subsequent solidification and oscillation behaviors of aluminum droplet fixed on the target surface was also investigated. It is interesting to find that the formation and distribution of the solidified surface morphology, such as the typical micron-sized ripples, are significantly affected by layer-by-layer solidification and underdamped oscillation in the remaining molten metal. Based on the above research, a semiquantitative relationship between external morphology and internal microstructure was proposed, which was further certified by investigating the piled vertical columns. The works should be helpful for the process optimization and non-destructive detection of drop-based 3D printing techniques.

  15. Boundary layer flow past a stretching/shrinking surface beneath an external uniform shear flow with a convective surface boundary condition in a nanofluid

    PubMed Central

    2011-01-01

    The problem of a steady boundary layer shear flow over a stretching/shrinking sheet in a nanofluid is studied numerically. The governing partial differential equations are transformed into ordinary differential equations using a similarity transformation, before being solved numerically by a Runge-Kutta-Fehlberg method with shooting technique. Two types of nanofluids, namely, Cu-water and Ag-water are used. The effects of nanoparticle volume fraction, the type of nanoparticles, the convective parameter, and the thermal conductivity on the heat transfer characteristics are discussed. It is found that the heat transfer rate at the surface increases with increasing nanoparticle volume fraction while it decreases with the convective parameter. Moreover, the heat transfer rate at the surface of Cu-water nanofluid is higher than that at the surface of Ag-water nanofluid even though the thermal conductivity of Ag is higher than that of Cu. PMID:21711841

  16. Boundary layer flow past a stretching/shrinking surface beneath an external uniform shear flow with a convective surface boundary condition in a nanofluid.

    PubMed

    Yacob, Nor Azizah; Ishak, Anuar; Pop, Ioan; Vajravelu, Kuppalapalle

    2011-04-07

    The problem of a steady boundary layer shear flow over a stretching/shrinking sheet in a nanofluid is studied numerically. The governing partial differential equations are transformed into ordinary differential equations using a similarity transformation, before being solved numerically by a Runge-Kutta-Fehlberg method with shooting technique. Two types of nanofluids, namely, Cu-water and Ag-water are used. The effects of nanoparticle volume fraction, the type of nanoparticles, the convective parameter, and the thermal conductivity on the heat transfer characteristics are discussed. It is found that the heat transfer rate at the surface increases with increasing nanoparticle volume fraction while it decreases with the convective parameter. Moreover, the heat transfer rate at the surface of Cu-water nanofluid is higher than that at the surface of Ag-water nanofluid even though the thermal conductivity of Ag is higher than that of Cu.

  17. Marangoni stresses and surface compression rheology of surfactant solutions. Achievements and problems.

    PubMed

    Langevin, D; Monroy, F

    2014-04-01

    In the presence of soluble surfactants, the motion of liquid surfaces involves Marangoni effects. As a consequence, the surfaces exhibit elastic responses, even frequently behaving as rigid surfaces, especially at low surfactant concentration. The Marangoni effects can be conveniently quantified introducing surface viscoelastic compression parameters that characterize the mechanical response of the surface near equilibrium. Many experimental techniques allow measuring the viscoelastic parameters. However, many difficulties are encountered during the interpretation of the surface response in the various types of hydrodynamic velocity fields involved in the different techniques. The role of adsorption and desorption energy barriers appears crucial, despite the fact that little is known yet about their values. In this short review, we will present examples illustrating the different problems. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Honeycomb-shaped surface topography induces differentiation of human mesenchymal stem cells (hMSCs): uniform porous polymer scaffolds prepared by the breath figure technique.

    PubMed

    Kawano, Takahito; Sato, Madoka; Yabu, Hiroshi; Shimomura, Masatsugu

    2013-11-29

    Polystyrene honeycomb scaffolds with different pore sizes were successfully fabricated by casting a polymer solution under humid conditions in order to investigate the effect of porous microtopography on hMSC differentiation. We have used honeycomb scaffolds to achieve the microtopography-induced differentiation of hMSCs. Honeycomb scaffolds led hMSCs to osteospecific and myospecific differentiations depending on the size of pores. This selective differentiation suggested that surface microtopography alone may be effective for using hMSCs in regenerative medicine and tissue engineering.

  19. Optimization of the coagulation-flocculation process for pulp mill wastewater treatment using a combination of uniform design and response surface methodology.

    PubMed

    Wang, Jian-Ping; Chen, Yong-Zhen; Wang, Yi; Yuan, Shi-Jie; Yu, Han-Qing

    2011-11-01

    Pulp mill wastewater was treated using the coagulation-flocculation process with aluminum chloride as the coagulant and a modified natural polymer, starch-g-PAM-g-PDMC [polyacrylamide and poly (2-methacryloyloxyethyl) trimethyl ammonium chloride], as the flocculant. A novel approach with a combination of response surface methodology (RSM) and uniform design (UD) was employed to evaluate the effects and interactions of three main influential factors, coagulant dosage, flocculant dosage and pH, on the treatment efficiency in terms of the supernatant turbidity and lignin removals as well as the water recovery. The optimal conditions obtained from the compromise of the three desirable responses, supernatant turbidity removal, lignin removal and water recovery efficiency, were as follows: coagulant dosage of 871 mg/L, flocculant dosage of 22.3 mg/L and pH 8.35. Confirmation experiments demonstrated that such a combination of the UD and RSM is a powerful and useful approach for optimizing the coagulation-flocculation process for the pulp mill wastewater treatment. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Uniform-burning matrix burner

    SciTech Connect

    Bohn, Mark S.; Anselmo, Mark

    2001-01-01

    Computer simulation was used in the development of an inward-burning, radial matrix gas burner and heat pipe heat exchanger. The burner and exchanger can be used to heat a Stirling engine on cloudy days when a solar dish, the normal source of heat, cannot be used. Geometrical requirements of the application forced the use of the inward burning approach, which presents difficulty in achieving a good flow distribution and air/fuel mixing. The present invention solved the problem by providing a plenum with just the right properties, which include good flow distribution and good air/fuel mixing with minimum residence time. CFD simulations were also used to help design the primary heat exchanger needed for this application which includes a plurality of pins emanating from the heat pipe. The system uses multiple inlet ports, an extended distance from the fuel inlet to the burner matrix, flow divider vanes, and a ring-shaped, porous grid to obtain a high-temperature uniform-heat radial burner. Ideal applications include dish/Stirling engines, steam reforming of hydrocarbons, glass working, and any process requiring high temperature heating of the outside surface of a cylindrical surface.

  1. Achieving ultra-hard surface of mechanically polished diamond crystal by thermo-chemical refinement

    NASA Astrophysics Data System (ADS)

    Zong, Wenjun; Zhang, Junjie; Liu, Yue; Sun, Tao

    2014-10-01

    In the present work, we propose a novel thermo-chemical post-processing method for refining the mechanically polished surface of natural diamond crystal. The deformation mechanisms of diamond crystal during mechanical polishing are elucidated by Raman Spectroscopy corroborated by molecular dynamics simulations. Moreover, the surface mechanical properties of diamond crystal are qualitatively characterized by nanoindentation tests. Our results reveal that under mechanical polishing there are phase transformations from diamond carbons to layered graphite, amorphous sp3 and sp2 hybrided structures occurred in the topmost surface layer, which consequently deteriorates the intrinsic surface strength of diamond crystal. In the following thermo-chemical refinement, the polishing-induced amorphous carbons, layered graphite and internal stress are largely removed through the weak oxidation reaction. It is found that the formation of considerable graphene structures in the topmost surface layer results in an ultra-hard diamond crystal surface with dramatically enhanced hardness and Young's modulus. Our findings shed light on the preparation of natural diamond crystal surface with superior mechanical properties.

  2. NASA Uniform Files Index

    NASA Technical Reports Server (NTRS)

    1987-01-01

    This handbook is a guide for the use of all personnel engaged in handling NASA files. It is issued in accordance with the regulations of the National Archives and Records Administration, in the Code of Federal Regulations Title 36, Part 1224, Files Management; and the Federal Information Resources Management Regulation, Subpart 201-45.108, Files Management. It is intended to provide a standardized classification and filing scheme to achieve maximum uniformity and ease in maintaining and using agency records. It is a framework for consistent organization of information in an arrangement that will be useful to current and future researchers. The NASA Uniform Files Index coding structure is composed of the subject classification table used for NASA management directives and the subject groups in the NASA scientific and technical information system. It is designed to correlate files throughout NASA and it is anticipated that it may be useful with automated filing systems. It is expected that in the conversion of current files to this arrangement it will be necessary to add tertiary subjects and make further subdivisions under the existing categories. Established primary and secondary subject categories may not be changed arbitrarily. Proposals for additional subject categories of NASA-wide applicability, and suggestions for improvement in this handbook, should be addressed to the Records Program Manager at the pertinent installation who will forward it to the NASA Records Management Office, Code NTR, for approval. This handbook is issued in loose-leaf form and will be revised by page changes.

  3. Optimization of Deposition Uniformity for Large Aperture NIF Substrates in a Planetary Rotation System

    SciTech Connect

    Oliver, J.B.; Talbot, D.

    2003-05-06

    Multilayer coatings on large substrates with increasingly complex spectral requirements are essential for a number of optical systems, placing stringent requirements on the error tolerances of individual layers. Each layer must be deposited quite uniformly over the entire substrate surface since any nonuniformity will add to the layer-thickness error level achieved. A deposition system containing a planetary rotation system with stationary uniformity masking is modeled, with refinements of the planetary gearing, source placement, and uniformity mask shape being utilized to achieve an optimal configuration. The impact of improper planetary gearing is demonstrated theoretically, as well as experimentally, providing more comprehensive requirements than simply avoiding repetition of previous paths through the vapor plume, until all possible combinations of gear teeth have been used. Deposition efficiency and the impact on the uniformity achieved are used to validate improved source placement.

  4. Oriented collagen as a potential cochlear implant electrode surface coating to achieve directed neurite outgrowth.

    PubMed

    Volkenstein, Stefan; Kirkwood, John E; Lai, Edwina; Dazert, Stefan; Fuller, Gerald G; Heller, Stefan

    2012-04-01

    In patients with severe to profound hearing loss, cochlear implants (CIs) are currently the only therapeutic option when the amplification with conventional hearing aids does no longer lead to a useful hearing experience. Despite its great success, there are patients in which benefit from these devices is rather limited. One reason may be a poor neuron-device interaction, where the electric fields generated by the electrode array excite a wide range of tonotopically organized spiral ganglion neurons at the cost of spatial resolution. Coating of CI electrodes to provide a welcoming environment combined with suitable surface chemistry (e.g. with neurotrophic factors) has been suggested to create a closer bioelectrical interface between the electrode array and the target tissue, which might lead to better spatial resolution, better frequency discrimination, and ultimately may improve speech perception in patients. Here we investigate the use of a collagen surface with a cholesteric banding structure, whose orientation can be systemically controlled as a guiding structure for neurite outgrowth. We demonstrate that spiral ganglion neurons survive on collagen-coated surfaces and display a directed neurite growth influenced by the direction of collagen fibril deposition. The majority of neurites grow parallel to the orientation direction of the collagen. We suggest collagen coating as a possible future option in CI technology to direct neurite outgrowth and improve hearing results for affected patients.

  5. Microwave-assisted green synthesis of Ag/reduced graphene oxide nanocomposite as a surface-enhanced Raman scattering substrate with high uniformity

    NASA Astrophysics Data System (ADS)

    Hsu, Kai-Chih; Chen, Dong-Hwang

    2014-04-01

    A nanocomposite of silver nanoparticles/reduced graphene oxide (Ag/rGO) has been fabricated as a surface-enhanced Raman scattering (SERS) substrate owing to the large surface area and two-dimensional nanosheet structure of rGO. A facile and rapid microwave-assisted green route has been used for the formation of Ag nanoparticles and the reduction of graphene oxide simultaneously with L-arginine as the reducing agent. By increasing the cycle number of microwave irradiation from 1 and 4 to 8, the mean diameters of Ag nanoparticles deposited on the surface of rGO increased from 10.3 ± 4.6 and 21.4 ± 10.5 to 41.1 ± 12.6 nm. The SERS performance of Ag/rGO nanocomposite was examined using the common Raman reporter molecule 4-aminothiophenol (4-ATP). It was found that the Raman intensity of 4-ATP could be significantly enhanced by increasing the size and content of silver nanoparticles deposited on rGO. Although the Raman intensities of D-band and G-band of rGO were also enhanced simultaneously by the deposited Ag nanoparticles which limited the further improvement of SERS detection sensitivity, the detectable concentration of 4-ATP with Ag/rGO nanocomposite as the SERS substrate still could be lowered to be 10-10 M and the enhancement factor could be increased to 1.27 × 1010. Furthermore, it was also achievable to lower the relative standard deviation (RSD) values of the Raman intensities to below 5%. This revealed that the Ag/rGO nanocomposite obtained in this work could be used as a SERS substrate with high sensitivity and homogeneity.

  6. Photo-induced electrochemical anodization of p-type silicon: achievement and demonstration of long term surface stability.

    PubMed

    Dhanekar, Saakshi; Islam, S S; Harsh

    2012-06-15

    Surface stability is achieved and demonstrated by porous silicon (PS) fabricated using a wavelength-dependent photo-electrochemical (PEC) anodization technique. During anodization, the photon flux for all wavelengths was kept constant while only the effect of light wavelength on the surface morphology of PS was investigated. PS optical sensors were realized, characterized and tested using a photoluminescence (PL) quenching technique. An aliphatic chain of alcohols (methanol to n-octanol) was detected in the range of 10-200 ppm. Long term surface stability was observed from samples prepared under red (750-620 nm) and green illumination (570-495 nm), where the PL quenching cycles evoke the possibility of using PS for stable sensor device applications. This study provides a route for preparing highly sensitive organic vapour sensors with a precise selection of the fabrication parameters and demonstrating their prolonged performance.

  7. Photo-induced electrochemical anodization of p-type silicon: achievement and demonstration of long term surface stability

    NASA Astrophysics Data System (ADS)

    Dhanekar, Saakshi; Islam, S. S.; Harsh

    2012-06-01

    Surface stability is achieved and demonstrated by porous silicon (PS) fabricated using a wavelength-dependent photo-electrochemical (PEC) anodization technique. During anodization, the photon flux for all wavelengths was kept constant while only the effect of light wavelength on the surface morphology of PS was investigated. PS optical sensors were realized, characterized and tested using a photoluminescence (PL) quenching technique. An aliphatic chain of alcohols (methanol to n-octanol) was detected in the range of 10-200 ppm. Long term surface stability was observed from samples prepared under red (750-620 nm) and green illumination (570-495 nm), where the PL quenching cycles evoke the possibility of using PS for stable sensor device applications. This study provides a route for preparing highly sensitive organic vapour sensors with a precise selection of the fabrication parameters and demonstrating their prolonged performance.

  8. Asymmetric material impact: Achieving free surfaces velocities nearly double that of the projectile

    SciTech Connect

    Aslam, Tariq; Dattelbaum, Dana; Gustavsen, Richard; Scharff, Robert; Byers, Mark

    2015-05-19

    Hypervelocity impact speeds are often limited by practical considerations in guns and explosive driven systems. In particular, for gas guns (both powder driven and light gas guns), there is the general trend that higher projectile speeds often come at the expense of smaller diameters, and thus less time for examining shock phenomena prior to two dimensional release waves affecting the observed quantities of interest. Similarly, explosive driven systems have their own set of limiting conditions due to limitations in explosive energy and size of devices required as engineering dimensions increase. The focus in this study is to present a methodology of obtaining free surface velocities well in excess of the projectile velocity. The key to this approach is in using a high impedance projectile that impacts a series of progressively lower impedance materials. The free surface velocity (if they were separated) of each of the progressively lower impedance materials would increase for each material. The theory behind this approach, as well as experimental results are presented.

  9. Asymmetric material impact: Achieving free surfaces velocities nearly double that of the projectile

    DOE PAGES

    Aslam, Tariq; Dattelbaum, Dana; Gustavsen, Richard; ...

    2015-05-19

    Hypervelocity impact speeds are often limited by practical considerations in guns and explosive driven systems. In particular, for gas guns (both powder driven and light gas guns), there is the general trend that higher projectile speeds often come at the expense of smaller diameters, and thus less time for examining shock phenomena prior to two dimensional release waves affecting the observed quantities of interest. Similarly, explosive driven systems have their own set of limiting conditions due to limitations in explosive energy and size of devices required as engineering dimensions increase. The focus in this study is to present a methodologymore » of obtaining free surface velocities well in excess of the projectile velocity. The key to this approach is in using a high impedance projectile that impacts a series of progressively lower impedance materials. The free surface velocity (if they were separated) of each of the progressively lower impedance materials would increase for each material. The theory behind this approach, as well as experimental results are presented.« less

  10. Challenges and Achievements in Circumpolar Monitoring of Land Surface Hydrology with Satellite Data

    NASA Astrophysics Data System (ADS)

    Bartsch, A.; Trofaier, A. M.; Widhalm, B.; Högström, E.; Leibman, M. O.; Dvornikov, Y.

    2014-12-01

    Land surface hydrology related features in arctic and sub-arctic environments which can be detected with satellite data include open water, near surface soil water storage, snow and freeze/thaw state. Their circumpolar spatial and temporal patterns are important for the understanding of land atmosphere exchange and changes in ground thermal properties. Datasets based on remotely sensed data are frequently used to evaluate climate models or to conduct trend analyses with respect to climate change. Although many circumpolar to global datasets are available, their applicability is often limited. A major challenge is the abundance of small lakes. This includes their impact on coarse resolution global products accuracy as well as their detection itself. Many studies have shown that the extent of the majority of tundra lakes is below the resolution of to date available global land cover datasets. An often followed strategy is to mosaic datasets from several months to years in order to overcome the problem of cloud coverage before application of long term change detection. However, many lakes vary seasonally in size. It can be shown that inundation patterns (with respect to lakes) are not limited to spring time by use of synthetic aperture radar (SAR). In addition seasonal changes of aquatic vegetation extent needs to be considered. This has been quantified over the Yamal region and a range of further sites (including PAGE21 sites, www.page21.eu) in Siberia.

  11. Achieving enhanced ionic mobility in nanoporous silica by controlled surface interactions.

    PubMed

    Garaga, Mounesha Nagendrachar; Aguilera, Luis; Yaghini, Negin; Matic, Aleksandar; Persson, Michael; Martinelli, Anna

    2017-02-22

    We report a strategy to enhance the ionic mobility in an emerging class of gels, based on robust nanoporous silica micro-particles, by chemical functionalization of the silica surface. Two very different ionic liquids are used to fill the nano-pores of silica at varying pore filling factors, namely one aprotic imidazolium based (1-methyl-3-hexylimidazolium bis(trifluoromethanesulfonyl)imide, C6C1ImTFSI), and one protic ammonium based (diethylmethylammonium methanesulfonate, DEMAOMs) ionic liquid. Both these ionic liquids display higher ionic mobility when confined in functionalized silica as compared to untreated silica nano-pores, an improvement that is more pronounced at low pore filling factors (i.e. in the nano-sized pore domains) and observed in the whole temperature window investigated (i.e. from -10 to 140 °C). Solid-state NMR, diffusion NMR and dielectric spectroscopy concomitantly demonstrate this effect. The origin of this enhancement is explained in terms of weaker intermolecular interactions and a consequent flipped-ion effect at the silica interface strongly supported by 2D solid-state NMR experiments. The possibility to significantly enhance the ionic mobility by controlling the nature of surface interactions is extremely important in the field of materials science and highlights these structurally tunable gels as promising solid-like electrolytes for use in energy relevant devices. These include, but are not limited to, Li-ion batteries and proton exchange membrane (PEM) fuel cells.

  12. The Uniform Rugosity Effect

    NASA Astrophysics Data System (ADS)

    Bonnivard, Matthieu; Bucur, Dorin

    2012-06-01

    Relying on the effect of microscopic asperities, one can mathematically justify that viscous fluids adhere completely on the boundary of an impermeable domain. The rugosity effect accounts asymptotically for the transformation of complete slip boundary conditions on a rough surface in total adherence boundary conditions, as the amplitude of the rugosities vanishes. The decreasing rate (average velocity divided by the amplitude of the rugosities) computed on close flat layers is definitely influenced by the geometry. Recent results prove that this ratio has a uniform upper bound for certain geometries, like periodical and "almost Lipschitz" boundaries. The purpose of this paper is to prove that such a result holds for arbitrary (non-periodical) crystalline boundaries and general (non-smooth) periodical boundaries.

  13. Automated Mars surface sample return mission concepts for achievement of essential scientific objectives

    NASA Technical Reports Server (NTRS)

    Weaver, W. L.; Norton, H. N.; Darnell, W. L.

    1975-01-01

    Mission concepts were investigated for automated return to Earth of a Mars surface sample adequate for detailed analyses in scientific laboratories. The minimum sample mass sufficient to meet scientific requirements was determined. Types of materials and supporting measurements for essential analyses are reported. A baseline trajectory profile was selected for its low energy requirements and relatively simple implementation, and trajectory profile design data were developed for 1979 and 1981 launch opportunities. Efficient spacecraft systems were conceived by utilizing existing technology where possible. Systems concepts emphasized the 1979 launch opportunity, and the applicability of results to other opportunities was assessed. It was shown that the baseline missions (return through Mars parking orbit) and some comparison missions (return after sample transfer in Mars orbit) can be accomplished by using a single Titan III E/Centaur as the launch vehicle. All missions investigated can be accomplished by use of Space Shuttle/Centaur vehicles.

  14. Optimization of direct drive irradiation uniformity of cylindrical target

    NASA Astrophysics Data System (ADS)

    Tian, Chao; Shan, Lianqiang; Zhou, Weimin; Liu, Dongxiao; Bi, Bi; Zhang, Feng; Wang, Weiwu; Yuan, Zongqiang; Yang, Lei; Gu, Yuqiu; Zhang, Baohan

    2017-07-01

    The irradiation uniformity of a cylindrical target directly driven by laser beams has been considered, which is relevant for fast ignition electron-transport experiments. The laser intensity distribution on the cylindrical target surface is analyzed and optimized by applying the polar direct drive technique and adjusting the laser beam parameters. Moreover, the rotation of laser spot around its propagation axis is taken into consideration. A case study based on the SG-III prototype laser configuration is presented to demonstrate the optimization approach. The irradiation uniformity is reduced from 10% to 1.6% for perfectly balanced beams, and the effects of uncertainties in beam errors (power imbalance and pointing error) are also studied. Furthermore, differences in laser absorption with different incident angles are taken into account and the results show that highly uniform energy deposition can be achieved.

  15. Achieving an ultra-narrow multiband light absorption meta-surface via coupling with an optical cavity

    NASA Astrophysics Data System (ADS)

    Liu, Zhengqi; Liu, Guiqiang; Liu, Xiaoshan; Huang, Shan; Wang, Yan; Pan, Pingping; Liu, Mulin

    2015-06-01

    Resonant plasmonic and metamaterial absorbers are of particular interest for applications in a wide variety of nanotechnologies including thermophotovoltaics, photothermal therapy, hot-electron collection and biosensing. However, it is rather challenging to realize ultra-narrow absorbers using plasmonic materials due to large optical losses in metals that inevitably decrease the quality of optical resonators. Here, we theoretically report methods to achieve an ultra-narrow light absorption meta-surface by using photonic modes of the optical cavities, which strongly couple with the plasmon resonances of the metallic nanostructures. Multispectral light absorption with absorption amplitude exceeding 99% and a bandwidth approaching 10 nm is achieved at the optical frequencies. Moreover, by introducing a thick dielectric coupling cavity, the number of absorption bands can be strongly increased and the bandwidth can even be narrowed to less than 5 nm due to the resonant spectrum splitting enabled by strong coupling between the plasmon resonances and the optical cavity modes. Designing such optical cavity-coupled meta-surface structures is a promising route for achieving ultra-narrow multiband absorbers, which can be used in absorption filters, narrow-band multispectral thermal emitters and thermophotovoltaics.

  16. Do School Uniforms Fit?

    ERIC Educational Resources Information Center

    White, Kerry A.

    2000-01-01

    In 1994, Long Beach (California) Unified School District began requiring uniforms in all elementary and middle schools. Now, half of all urban school systems and many suburban schools have uniform policies. Research on uniforms' effectiveness is mixed. Tightened dress codes may be just as effective and less litigious. (MLH)

  17. Do School Uniforms Fit?

    ERIC Educational Resources Information Center

    White, Kerry A.

    2000-01-01

    In 1994, Long Beach (California) Unified School District began requiring uniforms in all elementary and middle schools. Now, half of all urban school systems and many suburban schools have uniform policies. Research on uniforms' effectiveness is mixed. Tightened dress codes may be just as effective and less litigious. (MLH)

  18. Should Students Wear Uniforms?

    ERIC Educational Resources Information Center

    Cohn, Carol A.; Siegel, Loren

    1996-01-01

    Two essays present opposing viewpoints on school uniforms. One suggests that uniforms make safer schools and better students. The other states that teenagers will rebel, and the uniform debate is a diversion from more pressing problems in education. The article includes brief opinion statements from teachers and other professionals. (SM)

  19. School Uniforms Redux.

    ERIC Educational Resources Information Center

    Dowling-Sendor, Benjamin

    2002-01-01

    Reviews a recent decision in "Littlefield" by the 5th Circuit upholding a school uniform policy. Advises board member who wish to adopt a school uniform policy to solicit input from parents and students, research the experiences of other school districts with uniform policies, and articulate the interests they wish to promote through uniform…

  20. Full skin quantitative optical coherence elastography achieved by combining vibration and surface acoustic wave methods

    NASA Astrophysics Data System (ADS)

    Li, Chunhui; Guan, Guangying; Huang, Zhihong; Wang, Ruikang K.; Nabi, Ghulam

    2015-03-01

    By combining with the phase sensitive optical coherence tomography (PhS-OCT), vibration and surface acoustic wave (SAW) methods have been reported to provide elastography of skin tissue respectively. However, neither of these two methods can provide the elastography in full skin depth in current systems. This paper presents a feasibility study on an optical coherence elastography method which combines both vibration and SAW in order to give the quantitative mechanical properties of skin tissue with full depth range, including epidermis, dermis and subcutaneous fat. Experiments are carried out on layered tissue mimicking phantoms and in vivo human forearm and palm skin. A ring actuator generates vibration while a line actuator were used to excited SAWs. A PhS-OCT system is employed to provide the ultrahigh sensitive measurement of the generated waves. The experimental results demonstrate that by the combination of vibration and SAW method the full skin bulk mechanical properties can be quantitatively measured and further the elastography can be obtained with a sensing depth from ~0mm to ~4mm. This method is promising to apply in clinics where the quantitative elasticity of localized skin diseases is needed to aid the diagnosis and treatment.

  1. Student Achievement at CCCU-Member Colleges: A Comparison of CCCU Students' Outcomes on the Uniform CPA Exam to Students' Outcomes at AACSB and Other Institutions of Higher Education

    ERIC Educational Resources Information Center

    Hahn, William; Fairchild, Chris; Childs, R. Joseph

    2015-01-01

    This study investigated differences in Uniform Certified Public Accountant Exam (UCPAE) pass rates between candidates who graduated from Council for Christian Colleges & Universities member schools (CCCU-member) and candidates who graduated from institutions that are not CCCU members. The data set included 1,131 institutions (72,453…

  2. Student Achievement at CCCU-Member Colleges: A Comparison of CCCU Students' Outcomes on the Uniform CPA Exam to Students' Outcomes at AACSB and Other Institutions of Higher Education

    ERIC Educational Resources Information Center

    Hahn, William; Fairchild, Chris; Childs, R. Joseph

    2015-01-01

    This study investigated differences in Uniform Certified Public Accountant Exam (UCPAE) pass rates between candidates who graduated from Council for Christian Colleges & Universities member schools (CCCU-member) and candidates who graduated from institutions that are not CCCU members. The data set included 1,131 institutions (72,453…

  3. School Uniform Policies in Public Schools

    ERIC Educational Resources Information Center

    Brunsma, David L.

    2006-01-01

    The movement for school uniforms in public schools continues to grow despite the author's research indicating little if any impact on student behavior, achievement, and self-esteem. The author examines the distribution of uniform policies by region and demographics, the impact of these policies on perceptions of school climate and safety, and…

  4. Uniform Surface Modification of 3D Bioglass®-Based Scaffolds with Mesoporous Silica Particles (MCM-41) for Enhancing Drug Delivery Capability

    PubMed Central

    Boccardi, Elena; Philippart, Anahí; Juhasz-Bortuzzo, Judith A.; Beltrán, Ana M.; Novajra, Giorgia; Vitale-Brovarone, Chiara; Spiecker, Erdmann; Boccaccini, Aldo R.

    2015-01-01

    The design and characterization of a new family of multifunctional scaffolds based on bioactive glass (BG) of 45S5 composition for bone tissue engineering and drug delivery applications are presented. These BG-based scaffolds are developed via a replication method of polyurethane packaging foam. In order to increase the therapeutic functionality, the scaffolds were coated with mesoporous silica particles (MCM-41), which act as an in situ drug delivery system. These sub-micron spheres are characterized by large surface area and pore volume with a narrow pore diameter distribution. The solution used for the synthesis of the silica mesoporous particles was designed to obtain a high-ordered mesoporous structure and spherical shape – both are key factors for achieving the desired controlled drug release. The MCM-41 particles were synthesized directly inside the BG-based scaffolds, and the drug-release capability of this combined system was evaluated. Moreover, the effect of MCM-41 particle coating on the bioactivity of the BG-based scaffolds was assessed. The results indicate that it is possible to obtain a multifunctional scaffold system characterized by high and interconnected porosity, high bioactivity, and sustained drug delivery capability. PMID:26594642

  5. Toward Infection-Resistant Surfaces: Achieving High Antimicrobial Peptide Potency by Modulating the Functionality of Polymer Brush and Peptide.

    PubMed

    Yu, Kai; Lo, Joey C Y; Mei, Yan; Haney, Evan F; Siren, Erika; Kalathottukaren, Manu Thomas; Hancock, Robert E W; Lange, Dirk; Kizhakkedathu, Jayachandran N

    2015-12-30

    Bacterial infection associated with indwelling medical devices and implants is a major clinical issue, and the prevention or treatment of such infections is challenging. Antimicrobial coatings offer a significant step toward addressing this important clinical problem. Antimicrobial coatings based on tethered antimicrobial peptides (AMPs) on hydrophilic polymer brushes have been shown to be one of the most promising strategies to avoid bacterial colonization and have demonstrated broad spectrum activity. Optimal combinations of the functionality of the polymer-brush-tethered AMPs are essential to maintaining long-term AMP activity on the surface. However, there is limited knowledge currently available on this topic. Here we report the development of potent antimicrobial coatings on implant surfaces by elucidating the roles of polymer brush chemistry and peptide structure on the overall antimicrobial activity of the coatings. We screened several combinations of polymer brush coatings and AMPs constructed on nanoparticles, titanium surfaces, and quartz slides on their antimicrobial activity and bacterial adhesion against Gram-positive and Gram-negative bacteria. Highly efficient killing of planktonic bacteria by the antimicrobial coatings on nanoparticle surfaces, as well as potent killing of adhered bacteria in the case of coatings on titanium surfaces, was observed. Remarkably, the antimicrobial activity of AMP-conjugated brush coatings demonstrated a clear dependence on the polymer brush chemistry and peptide structure, and optimization of these parameters is critical to achieving infection-resistant surfaces. By analyzing the interaction of polymer-brush-tethered AMPs with model lipid membranes using circular dichroism spectroscopy, we determined that the polymer brush chemistry has an influence on the extent of secondary structure change of tethered peptides before and after interaction with biomembranes. The peptide structure also has an influence on the density

  6. Uniform Media Effects and Uniform Audience Responses.

    ERIC Educational Resources Information Center

    Perry, David K.

    The idea that mass communication effects may decrease diversity among people or societies exposed to it arises constantly. However, discussions of mass media effects do not highlight differences between mass communications that "affect" people uniformly and messages that members of audiences "respond to" in similar ways. A…

  7. Uniform insulation applied-B ion diode

    DOEpatents

    Seidel, David B.; Slutz, Stephen A.

    1988-01-01

    An applied-B field extraction ion diode has uniform insulation over an anode surface for increased efficiency. When the uniform insulation is accomplished with anode coils, and a charge-exchange foil is properly placed, the ions may be focused at a point on the z axis.

  8. Uniform Continuity of POVMs

    NASA Astrophysics Data System (ADS)

    Beneduci, Roberto

    2014-10-01

    Recently a characterization of uniformly continuous POVMs and a necessary condition for a uniformly continuous POVM F to have the norm-1 property have been provided. Moreover it was proved that in the commutative case, uniform continuity corresponds to the existence of a Feller Markov kernel. We apply such results to the analysis of some relevant physical examples; i.e., the phase space localization observables, the unsharp phase observable and the unsharp number observable of which we study the uniform continuity, the norm-1 property and the existence of a Feller Markov kernel.

  9. STRUCTURE OF UNIFORMLY ROTATING STARS

    SciTech Connect

    Deupree, Robert G.

    2011-07-10

    Zero-age main-sequence models of uniformly rotating stars have been computed for 10 masses between 1.625 and 8 M{sub sun} and for 21 rotation rates from zero to nearly critical rotation. The surface shape is used to distinguish rotation rather than the surface equatorial velocity or the rotation rate. Using the surface shape is close, but not quite equivalent, to using the ratio of the rotation rate to the critical rotation rate. Using constant shape as the rotation variable means that it and the mass are separable, something that is not true for either the rotation rate or surface equatorial velocity. Thus, a number of properties, including the ratio of the effective temperature anywhere on the surface to the equatorial temperature, are nearly independent of the mass of the model, as long as the rotation rate changes in such a way as to keep the surface shape constant.

  10. Kinetics of Hepatitis B Surface Antigen Level in Chronic Hepatitis B Patients who Achieved Hepatitis B Surface Antigen Loss during Pegylated Interferon Alpha-2a Treatment

    PubMed Central

    Li, Ming-Hui; Zhang, Lu; Qu, Xiao-Jing; Lu, Yao; Shen, Ge; Wu, Shu-Ling; Chang, Min; Liu, Ru-Yu; Hu, Lei-Ping; Li, Zhen-Zhen; Hua, Wen-Hao; Song, Shu-Jing; Xie, Yao

    2017-01-01

    Background: Hepatitis B surface antigen (HBsAg) loss/seroconversion is considered to be the ideal endpoint of antiviral therapy and the ultimate treatment goal in chronic hepatitis B (CHB). This study aimed to assess the patterns of HBsAg kinetics in CHB patients who achieved HBsAg loss during the treatment of pegylated interferon (PEG-IFN) α-2a. Methods: A total of 150 patients were enrolled, composing of 83 hepatitis B envelope antigen (HBeAg)-positive and 67 HBeAg-negative patients. Patients were treated with PEG-IFN α-2a180 μg/week until HBsAg loss/seroconversion was achieved, which occurred within 96 weeks. Serum hepatitis B virus deoxyribonucleic acid and serological indicators (HBsAg, anti-HBs, HBeAg, and anti-HBe) were determined before and every 3 months during PEG-IFN α-2a treatment. Biochemical markers and peripheral blood neutrophil and platelet counts were tested every 1–3 months. Results: Baseline HBsAg levels were 2.5 ± 1.3 log IU/ml, and decreased rapidly at 12 and 24 weeks by 48.3% and 88.3%, respectively. The mean time to HBsAg loss was 54.2 ± 30.4 weeks, though most patients needed extended treatment and 30.0% of HBsAg loss occurred during 72–96 weeks. Baseline HBsAg levels were significantly higher in HBeAg-positive patients (2.9 ± 1.1 log IU/ml) compared with HBeAg-negative patients (2.0 ± 1.3 log IU/ml; t = 4.733, P < 0.001), but the HBsAg kinetics were similar. Patients who achieved HBsAg loss within 48 weeks had significantly lower baseline HBsAg levels and had more rapid decline of HBsAg at 12 weeks compared to patients who needed extended treatment to achieve HBsAg loss. Conclusions: Patients with lower baseline HBsAg levels and more rapid decline during early treatment with PEG-IFN are more likely to achieve HBsAg loss during 96 weeks of treatment, and extended therapy longer than 48 weeks may be required to achieve HBsAg loss. PMID:28229987

  11. Application of Plackett-Burman design and response surface methodology to achieve exponential growth for aggregated shipworm bacterium.

    PubMed

    Ahuja, S K; Ferreira, G M; Moreira, A R

    2004-03-20

    Here we report the successful implementation of the Plackett-Burman multifactorial design to screen the limiting components for growth and subsequent use of the response surface methodology (RSM) to design a medium that supported exponential growth of the aggregated morphology of the shipworm bacterium, Teredinobacter turnirae. The results obtained with the help of Plackett-Burman design indicated limitations of three components in the growth medium, MnCl2.4H2O, Na2CO3, and K2HPO4. The concentrations of these three components were further optimized using RSM. By increasing the concentrations of the above-mentioned components by 4-fold, 12-fold, and 12-fold, respectively, it became possible to achieve exponential growth of the culture.

  12. 3D numerical analysis of influence of the non-uniform deposition rate on the hillock density at HVPE-GaN surface

    NASA Astrophysics Data System (ADS)

    Han, Xue-Feng; Lee, Jae-Hak; Lee, Yoo-Jin; Song, Jae-Ho; Yi, Kyung-Woo

    2017-09-01

    In this study, hydride vapor phase epitaxy (HVPE), one of the feasible methods to produce the GaN thin film, has been used to conduct experiments under different temperatures. In order to study the factors affecting the distribution of the density of the hillocks along radial direction, we have conducted a 3D calculation to observe the fluid flow, mass transfer and deposition rate distribution using the CFD-ACE program. The numerical results have shown that the wafers have experienced high and low growth rate alternately. The growth rate fluctuations at different distances from the inlets are compared by standard deviation analysis. These standard deviations of deposition rates along the azimuthal direction increase from the center to the periphery, which might explain why the density of the hillocks increases from the center to the periphery in the experiments. Moreover, it is found that the non-uniform deposition rates are the result of low speed rotation of the susceptor. Increasing the rotation speed of the susceptor increases the uniformity of the gas flow pattern and deposition rate, which means that the high rotation speed can decrease the standard deviation of the deposition rate along azimuthal direction. Consequently, the density of the hillocks can be decreased.

  13. Manual on School Uniforms.

    ERIC Educational Resources Information Center

    Department of Justice, Washington, DC.

    In response to growing levels of violence in American schools, many communities are deciding to adopt school-uniform policies as part of an overall program to improve school safety and discipline. This document provides the following guidelines for parents, teachers, and school leaders who may consider adopting a school-uniform policy: (1) Get…

  14. Dress Codes and Uniforms.

    ERIC Educational Resources Information Center

    Lumsden, Linda; Miller, Gabriel

    2002-01-01

    Students do not always make choices that adults agree with in their choice of school dress. Dress-code issues are explored in this Research Roundup, and guidance is offered to principals seeking to maintain a positive school climate. In "Do School Uniforms Fit?" Kerry White discusses arguments for and against school uniforms and summarizes the…

  15. Is the Target of 1 Day of Stay per 1% Total Body Surface Area Burned Achieved in Chemical Burns?

    PubMed

    Tan, Teresa; Wong, David S Y

    2016-02-01

    The length of hospital stay (LOS) is a standard parameter used to reflect quality and evaluate outcomes in acute burn care. This study aims to assess whether the target of 1 day of stay per 1% total body surface area (TBSA) burned was achieved in acute chemical burns management and factors affecting the LOS. A retrospective analysis of the records of patients who suffered from chemical burn injuries admitted to a university burn center over a continuous 14-year period was performed.A total of 118 patients were admitted over the period for chemical burns. Only 14% of cases achieved the target stated. Factors associated with lengthening of the hospital stay included TBSA, ocular involvement, the cause of injury, and the need for surgery during the same admission.The LOS in chemical burns frequently exceeds 1 day of stay per 1% TBSA burned. Many factors can contribute to a patient's LOS and are worth exploring in order to see if the impact of these factors could be minimized. Early surgical intervention should help to reduce the LOS if reliable methods of burn wound depth assessment are available.

  16. Effects of surface roughness on non-uniform phases of superfluid 3He and spin-triplet models for Sr2RuO4

    NASA Astrophysics Data System (ADS)

    Vorontsov, Anton; Sauls, James

    2014-03-01

    We present theoretical and computational results for the spectrum of surface bound states of confined superfluid 3He and spin-triplet, odd-parity pairing theories of Sr2RuO4. The surface states, despite being related to the topological structure of the condensed state, are sensitive to surface disorder. We investigate effects of surface roughness on the physical properties of the boundary layer of several coherence lengths. We find that for confined 3He-A or chiral phases proposed for Sr2RuO4 the spatial profile of the edge current is significantly modified for atomically rough surfaces compared to that for specular surfaces. The boundary effect is strongly reflected in the ground-state angular momentum generated by the edge states. In thin films of superfluid 3He with rough surfaces the effect of surface scattering is expected to be even more important since surface states dominate the thermodynamic properties. For specular boundaries we predicted new phases with spontaneously broken time-reversal or translational symmetries should appear in films of D ~ 10ξ0 . We report results for the phase diagram for specular, diffuse and maximal pair-breaking resulting from retro-reflecting boundaries. Supported by NSF Grants DMR-0954342 and DMR-1106315.

  17. Optimization of deposition uniformity for large-aperture National Ignition Facility substrates in a planetary rotation system

    SciTech Connect

    Oliver, J.B.; Talbot, D.

    2006-05-17

    Multilayer coatings on large substrates with increasingly complex spectral requirements are essential for a number of optical systems, placing stringent requirements on the error tolerances of individual layers. Each layer must be deposited quite uniformly over the entire substate surface since any nonuniformity will add to the layer-thickness error level achieved. A deposition system containing a planetary rotation system with stationary uniformity masking is modeled, with refinements of the planetary gearing, source placement, and uniformity mask shape being utilized to achieve an optimal configuration. The impact of improper planetary gearing is demonstrated theoretically, as well as experimentally, providing more comprehensive requirements than simply avoiding repetition of previous paths through the vapor plume, until all possible combinations of gear teeth have been used. Deposition efficiency and the impact of changing vapor plume conditions on the uniformity achieved are used to validate improved source placement.

  18. Energy spectrum of surface electrons over a 3He - 4He solution with a spatially non-uniform distribution of the light isotope

    NASA Astrophysics Data System (ADS)

    Bezsmolnyy, Ya. Yu.; Sokolova, E. S.; Sokolov, S. S.; Studart, Nelson

    2017-02-01

    The energy gap between the ground and first excited energy levels of surface electrons deposited over a dilute 3He - 4He solution is evaluated. Two spatial distributions of 3He atoms near the free surface solution are considered. One consists of a thin though macroscopic 3He film and in the other the 3He concentration varies continuously from the surface inside the liquid. The energy gap is calculated as a function of the parameters of the 3He spatial distribution for these distributions. It is shown that the energy gap dependence on the distribution parameters allows using measurements of intersubband transitions of the surface electrons to determine the 3He concentration distribution and, in principle, the nature of the spatial distribution of the light isotope near the surface of the solution.

  19. Inverse modeling of surface-water discharge to achieve restoration salinity performance measures in Florida Bay, Florida

    USGS Publications Warehouse

    Swain, E.D.; James, D.E.

    2008-01-01

    The use of numerical modeling to evaluate regional water-management practices involves the simulation of various alternative water-delivery scenarios, which typically are designed intuitively rather than analytically. These scenario simulations are used to analyze how specific water-management practices affect factors such as water levels, flows, and salinities. In lieu of testing a variety of scenario simulations in a trial-and-error manner, an optimization technique may be used to more precisely and directly define good water-management alternatives. A numerical model application in the coastal regions of Florida Bay and Everglades National Park (ENP), representing the surface- and ground-water hydrology for the region, is a good example of a tool used to evaluate restoration scenarios. The Southern Inland and Coastal System (SICS) model simulates this area with a two-dimensional hydrodynamic surface-water model and a three-dimensional ground-water model, linked to represent the interaction of the two systems with salinity transport. This coastal wetland environment is of great interest in restoration efforts, and the SICS model is used to analyze the effects of alternative water-management scenarios. The SICS model is run within an inverse modeling program called UCODE. In this application, UCODE adjusts the regulated inflows to ENP while SICS is run iteratively. UCODE creates parameters that define inflow within an allowable range for the SICS model based on SICS model output statistics, with the objective of matching user-defined target salinities that meet ecosystem restoration criteria. Preliminary results obtained using two different parameterization methods illustrate the ability of the model to achieve the goals of adjusting the range and reducing the variance of salinity values in the target area. The salinity variance in the primary zone of interest was reduced from an original value of 0.509 psu2 to values 0.418 psu2 and 0.342 psu2 using different

  20. Computational modeling of geometry effects on the IDL surface concentration in the presence of non-uniform magnetic field - links to atherosclerosis

    NASA Astrophysics Data System (ADS)

    Aminfar, H.; Mohammadpourfard, M.; Khajeh, K.

    2016-01-01

    Effect of geometry on the atherosclerosis is a significant issue, so the 3D s-shape and 2D axisymmetric stenosis tube as a blood vessel have been analyzed in this work. This paper has focused on the most important parameters in the LSC uptake, inlet Re number and infiltration velocity in the presence of non-uniform magnetic field. The magnetic field is arising from the thin wire with electric current placed vertically to the arterial blood vessel. According to the results of this study, applying magnetic field can be a treatment for atherosclerosis by reducing LSC along the vessel wall. It is observed that, application of magnetic field leads to production of a vortex in the flow, high strain rate, increment of WSS, and also reduction in LSC. For solving the mass transport equation, Lumen-wall model has been used. Blood flow has been considered laminar and incompressible containing Ferro fluid (blood and 4 vol% Fe3O4) under steady state conditions. Numerical solution of governing equations was obtained by using the single-phase model and control volume technique for flow field.

  1. Numerical investigation on laminar round-jet impinging on a surface at uniform heat flux in a channel partially filled with a porous medium

    NASA Astrophysics Data System (ADS)

    Buonomo, B.; Diana, A.; Manca, O.; Nardini, S.

    2017-01-01

    Horizontal channel partially filled with porous media and a single round jet impinging on the porous medium are numerically investigated. The wall facing the round jet is partially heated at uniform heat flux. A two-dimensional axial symmetric flow in the channel is assumed to evaluate the thermal behavior within the channel. The analysis in the porous medium is accomplished in local thermal equilibrium conditions and under the Brinkman–Forchheimer-extended Darcy law assumption. The problem is solved employing the Ansys-Fluent code. Results are given in terms of stream function and temperature fields of fluid and solid matrix, wall temperature profiles, air velocity and temperature profiles along the transversal section of channel. The Peclet number ranges from 1 to 1000 and Rayleigh number values are 10, 50, 100 and 1000. Reynolds jet number, solid wall distance and wall heat flux effects on thermal and fluid dynamic behaviors are investigated. Results indicate that Nusselt number has the highest value for the channel with a porous medium of thickness equal to the channel gap, whereas it presents very small changes increasing the porous medium length on the heated wall. Correlations among average Nusselt, Peclet and Rayleigh numbers are proposed.

  2. Single and Double ITCZ in Aqua-Planet Models with Globally and Temporally Uniform Sea Surface Temperature and Solar Insolation: An Interpretation

    NASA Technical Reports Server (NTRS)

    Chao, Winston C.; Chen, Baode; Lau, William K. M. (Technical Monitor)

    2002-01-01

    Previous studies (Chao 2000, Chao and Chen 2001, Kirtman and Schneider 2000, Sumi 1992) have shown that, by means of one of several model design changes, the structure of the ITCZ in an aqua-planet model with globally uniform SST and solar angle (U-SST-SA) can change between a single ITCZ at the equator and a double ITCZ straddling the equator. These model design changes include switching to a different cumulus parameterization scheme (e.g., from relaxed Arakawa Schubert scheme (RAS) to moist convective adjustment scheme (MCA)), changes within the cumulus parameterization scheme, and changes in other aspects of the model, such as horizontal resolution. Sometimes only one component of the double ITCZ shows up; but still this is an ITCZ away from the equator, quite distinct from a single ITCZ over the equator. Since these model results were obtained by different investigators using different models which have yielded reasonable general circulation, they are considered as reliable. Chao and Chen (2001; hereafter CC01) have made an initial attempt to interpret these findings based on the concept of rotational ITCZ attractors that they introduced. The purpose of this paper is to offer a more complete interpretation.

  3. Maximum surface charge density for triboelectric nanogenerators achieved by ionized-air injection: methodology and theoretical understanding.

    PubMed

    Wang, Sihong; Xie, Yannan; Niu, Simiao; Lin, Long; Liu, Chang; Zhou, Yu Sheng; Wang, Zhong Lin

    2014-10-22

    For the maximization of the surface charge density in triboelectric nanogenerators, a new method of injecting single-polarity ions onto surfaces is introduced for the generation of surface charges. The triboelectric nanogenerator's output power gets greatly enhanced and its maximum surface charge density is systematically studied, which shows a huge room for the improvement of the output of triboelectric nanogenerators by surface modification.

  4. Gracilaria lemaneiformis polysaccharide as integrin-targeting surface decorator of selenium nanoparticles to achieve enhanced anticancer efficacy.

    PubMed

    Jiang, Wenting; Fu, Yuanting; Yang, Fang; Yang, Yufeng; Liu, Ting; Zheng, Wenjie; Zeng, Lilan; Chen, Tianfeng

    2014-08-27

    The poor permeability of glioma parenchyma represents a major limit for antiglioblastoma drug delivery. Gracilaria lemaneiformis polysaccharide (GLP), which has a high binding affinity to αvβ3 integrin overexpressed in glioma cells, was employed in the present study to functionalize selenium nanoparticles (SeNPs) to achieve antiglioblastoma efficacy. GLP-SeNPs showed satisfactory size distribution, high stability, and selectivity between cancer and normal cells. In U87 glioma cell membrane, which has a high integrin expression level, GLP-SeNPs exhibited significantly higher cellular uptake than unmodified SeNPs. As expected, U87 cells exhibited a greater uptake of GLP-SeNPs than C6 cells with low integrin expression level. Furthermore, the internalization of GLP-SeNPs was inhibited by cyclo-(Arg-Gly-Asp-Phe-Lys) peptides, suggesting that cellular uptake into U87 cells and C6 cells occurred via αvβ3 integrin-mediated endocytosis. For U87 cells, the cytotoxicity of SeNPs decorated by GLP was enhanced significantly because of the induction of various apoptosis signaling pathways. Internalized GLP-SeNPs triggered intracellular reactive oxygen species downregulation. Therefore, p53, MAPKs, and AKT pathways were activated to advance cell apoptosis. These findings suggest that surface decoration of nanomaterials with GLP could be an efficient strategy for design and preparation of glioblastoma targeting nanodrugs.

  5. Use of diesel engine and surface-piercing propeller to achieve fuel savings for inshore fishing boats

    NASA Astrophysics Data System (ADS)

    Zainol, Ismail; Yaakob, Omar

    2016-06-01

    Fishing is a major local industry in Malaysia, particularly in rural areas. However, the rapidly increasing price of fuel is seriously affecting the industry's viability. At present, outboard petrol engines are the preferred choice for use in small-scale fishing boats because they deliver the advantages of high speed and low weight, they are easy to install, and they use minimal space. Petrol outboard engines are known to consume a greater amount of fuel than inboard diesel engines, but installing diesel engines with conventional submerged propellers in existing small-scale fishing boats is not economically viable because major hullform modifications and extra expenditure are required to achieve this. This study describes a proposal to enable reductions in fuel consumption by introducing the combined use of a diesel engine and surface-piercing propeller (SPP). An analysis of fuel consumption reduction is presented, together with an economic feasibility study. Resulting data reveal that the use of the proposed modifications would save 23.31 liters of fuel per trip (40.75 %) compared to outboard motors, equaling annual savings of RM 3962 per year.

  6. Optimal wavelengths obtained from laws analogous to the Wien's law for monospectral and bispectral methods, and general methodology for multispectral temperature measurements taking into account global transfer function including non-uniform emissivity of surfaces

    NASA Astrophysics Data System (ADS)

    Rodiet, Christophe; Remy, Benjamin; Degiovanni, Alain

    2016-05-01

    In this paper, it is shown how to select the optimal wavelengths minimizing the relative error and the standard deviation of the temperature. Furthermore, it is shown that the optimal wavelengths in mono-spectral and bi-spectral methods (for a Planck's law) can be determined by laws analogous to the displacement Wien's law. The simplicity of these laws can thus allow real-time selection of optimal wavelengths for a control/optimization of industrial processes, for example. A more general methodology to obtain the optimal wavelengths selection in a multi-spectral method (taking into account the spectral variations of the global transfer function including the emissivity variations) for temperature measurement of surfaces exhibiting non-uniform emissivity, is also presented. This latter can then find an interest in glass furnaces temperature measurement with spatiotemporal non-uniformities of emissivity, the control of biomass pyrolysis, the surface temperature measurement of buildings or heating devices, for example. The goal consists of minimizing the standard deviation of the estimated temperature (optimal design experiment). For the multi-spectral method, two cases will be treated: optimal global and optimal constrained wavelengths selection (to the spectral range of the detector, for example). The estimated temperature results obtained by different models and for different number of parameters and wavelengths are compared. These different points are treated from theoretical, numerical and experimental points of view.

  7. Immobilization of biotinylated hGBP1 in a defined orientation on surfaces is crucial for uniform interaction with analyte proteins and catalytic activity.

    PubMed

    Syguda, Adrian; Kerstan, Andreas; Ladnorg, Tatjana; Stüben, Florian; Wöll, Christof; Herrmann, Christian

    2012-04-17

    Guanylate binding proteins (GBPs) belong to the dynamin superfamily of large GTP binding proteins. A biochemical feature common to these proteins is guanosine-triphosphate (GTP) binding leading to self-assembly of the proteins, and this in turn results in higher catalytic GTP hydrolysis activity. In the case of human guanylate binding protein 1 (hGBP1) homodimer formation is observed after binding of nonhydrolyzable GTP analogs like GppNHp. hGBP1 is one of seven GBP isoforms identified in human. While cellular studies suggest heterocomplex formation of various isoforms biochemical binding studies in quantitative terms are lacking. In this work we established a method to study hGBP1 interactions by attaching this protein in a defined orientation to a surface allowing for interaction with molecules from the solution. Briefly, specifically biotinylated hGBP1 is attached to a streptavidin layer on a self-assembled monolayer (SAM) surface allowing for characterization of the packing density of the immobilized protein by surface plasmon resonance (SPR) technology and atomic force microscopy (AFM), respectively. In addition, the enzymatic activity of immobilized hGBP1 and the kinetics of interaction with binding partners in solution are quantified. We present a procedure for attaching an enzyme in a defined orientation to a surface which exposes its active end, the GTPase domain to the solution resulting in a homogeneous population of this enzyme in terms of enzymatic activity and of interaction with soluble proteins.

  8. Uniformly dense polymeric foam body

    DOEpatents

    Whinnery, Jr., Leroy

    2003-07-15

    A method for providing a uniformly dense polymer foam body having a density between about 0.013 g/cm.sup.3 to about 0.5 g/cm.sup.3 is disclosed. The method utilizes a thermally expandable polymer microsphere material wherein some of the microspheres are unexpanded and some are only partially expanded. It is shown that by mixing the two types of materials in appropriate ratios to achieve the desired bulk final density, filling a mold with this mixture so as to displace all or essentially all of the internal volume of the mold, heating the mold for a predetermined interval at a temperature above about 130.degree. C., and then cooling the mold to a temperature below 80.degree. C. the molded part achieves a bulk density which varies by less then about .+-.6% everywhere throughout the part volume.

  9. Prediction of the optimum surface orientation angles to achieve maximum solar radiation using Particle Swarm Optimization in Sabha City Libya

    NASA Astrophysics Data System (ADS)

    Mansour, F. A.; Nizam, M.; Anwar, M.

    2017-02-01

    This research aims to predict the optimum surface orientation angles in solar panel installation to achieve maximum solar radiation. Incident solar radiation is calculated using koronakis mathematical model. Particle Swarm Optimization (PSO) is used as computational method to find optimum angle orientation for solar panel installation in order to get maximum solar radiation. A series of simulation has been carried out to calculate solar radiation based on monthly, seasonally, semi-yearly and yearly period. South-facing was calculated also as comparison of proposed method. South-facing considers azimuth of 0°. Proposed method attains higher incident predictions than South-facing that recorded 2511.03 kWh/m2for monthly. It were about 2486.49 kWh/m2, 2482.13 kWh/m2and 2367.68 kWh/m2 for seasonally, semi-yearly and yearly. South-facing predicted approximately 2496.89 kWh/m2, 2472.40 kWh/m2, 2468.96 kWh/m2, 2356.09 kWh/m2for monthly, seasonally, semi-yearly and yearly periods respectively. Semi-yearly is the best choice because it needs twice adjustments of solar panel in a year. Yet it considers inefficient to adjust solar panel position in every season or monthly with no significant solar radiation increase than semi-yearly and solar tracking device still considers costly in solar energy system. PSO was able to predict accurately with simple concept, easy and computationally efficient. It has been proven by finding the best fitness faster.

  10. Radially uniform electron source

    NASA Technical Reports Server (NTRS)

    Mccomas, D.; Bame, S. J.

    1982-01-01

    A thermionic electron source capable of producing uniform count rates in a number of channel electron multipliers simultaneously was required for conditioning multipliers for an extended space mission. It was found that a straight tungsten filament in the center of a cylindrically symmetric geometry surrounded by an array of multipliers emits a radially asymmetric distribution of electrons that changes with time. A source was developed which successfully produces a time-independent radially uniform distribution of electrons by moving the filament out of the direct line of sight and replacing it with a centrally located electron 'cloud.'

  11. Synthesis and surface modification of uniform MFe2O4 (M = Fe, Mn, and Co) nanoparticles with tunable sizes and functionalities

    NASA Astrophysics Data System (ADS)

    Cabrera, Lourdes I.; Somoza, Álvaro; Marco, José F.; Serna, Carlos J.; Puerto Morales, M.

    2012-06-01

    Cubic monodisperse MFe2O4 ferrite nanoparticles (M = Fe, Co, and Mn) with tunable sizes between 7 and 20 nm and a narrow size distribution have been achieved in a one step synthesis by thermal decomposition of Fe(III), Co (II), and Mn(II) oleates. These nanoparticles have been functionalized with dimercaptosuccinic acid (DMSA), 11-mercaptoundecanoic acid (MUA), and bis(carboxymethyl)(2-maleimidylethyl)ammonium 4-toluenesulfonate (MATS) to grant them aqueous stability and the possibility for further functionalization with different biomolecules. Their structural, magnetic, and colloidal properties have also been studied to determine their chemical and physical properties and the degree of stability under physiological conditions that will determine their future use in biomedical applications.

  12. High speed inscription of uniform, large-area laser-induced periodic surface structures in Cr films using a high repetition rate fs laser.

    PubMed

    Ruiz de la Cruz, A; Lahoz, R; Siegel, J; de la Fuente, G F; Solis, J

    2014-04-15

    We report on the fabrication of laser-induced periodic surface structures in Cr films upon high repetition rate fs laser irradiation (up to 1 MHz, 500 fs, 1030 nm), employing beam scanning. Highly regular large-area (9  cm2) gratings with a relative diffraction efficiency of 42% can be produced within less than 6 min. The ripple period at moderate and high fluences is 0.9 μm, with a small period of 0.5 μm appearing at lower energies. The role of the irradiation parameters on the characteristics of the laser-induced periodic surface structures (LIPSS) is studied and discussed in the frame of the models presently used. We have identified the polarization vector orientation with respect to the scan direction as a key parameter for the fabrication of high-quality, large-area LIPSS, which, for perpendicular orientation, allows the coherent extension of the sub-wavelength structure over macroscopic distances. The processing strategy is robust in terms of broad parameter windows and applicable to other materials featuring LIPSS.

  13. Thermal radiation and Hall effects on boundary layer flow past a non-isothermal stretching surface embedded in porous medium with non-uniform heat source/sink and fluid-particle suspension

    NASA Astrophysics Data System (ADS)

    Gireesha, B. J.; Mahanthesh, B.; Gorla, Rama Subba Reddy; Manjunatha, P. T.

    2016-04-01

    Theoretical study on hydromagnetic heat transfer in dusty viscous fluid on continuously stretching non-isothermal surface, with linear variation of surface temperature or heat flux has been carried out. Effects of Hall current, Darcy porous medium, thermal radiation and non-uniform heat source/sink are taken into the account. The sheet is considered to be permeable to allow fluid suction or blowing, and stretching with a surface velocity varied according to a linear. Two cases of the temperature boundary conditions were considered at the surface namely, PST and PHF cases. The governing partial differential equations are transferred to a system of non-linear ordinary differential equations by employing suitable similarity transformations and then they are solved numerically. Effects of various pertinent parameters on flow and heat transfer for both phases is analyzed and discussed through graphs in detail. The values of skin friction and Nusselt number for different governing parameters are also tabulated. Comparison of the present results with known numerical results is presented and an excellent agreement is found.

  14. Uniformity in Tetrahedral Hohlraums

    NASA Astrophysics Data System (ADS)

    Craxton, R. S.; Schnittman, J. D.; Pollaine, S. M.

    1996-11-01

    Tetrahedral hohlraums, i.e., spherical hohlraums with four laser entrance holes (LEH's), offer an alternative means of obtaining good time-independent capsule irradiation uniformity. Since the laser spots are spread fairly uniformly over the hohlraum wall, time-dependent uniformity swings are minimized. Using the 3-D view-factor code BUTTERCUP we have found, for both OMEGA and the NIF, that the uniformity is typically ~2% rms at all times, mainly in the Y_32 mode, but can be reduced to ~1% by independently varying the power in each beam. We have investigated the sensitivity of tetrahedral hohlraums to errors in beam-energy balance and pointing, and we have examined how large the LEH's must be to allow the beams to go through without refraction or absorption. This work was supported by the U.S. Department of Energy Office of Inertial Confinement Fusion under Cooperative Agreement No. DE-FC03-92SF19460. *Also Lawrence Livermore National Laboratory.

  15. Custom uniform source system

    NASA Technical Reports Server (NTRS)

    Balcom, John L.

    1994-01-01

    The purpose and scope of this final report is to provide information on the Custom Uniform Source System (CSTM-USS-4000). The report includes documentation and summaries of the results for the work performed under the contract. The Annex contain laboratory test findings, photographs, and drawings of the sphere system.

  16. Uniform Federal Accessibility Standards.

    ERIC Educational Resources Information Center

    Department of Housing and Urban Development, Washington, DC.

    The document presents uniform standards for facility accessibility by physically handicapped persons for Federal and federally funded facilities. The standards are to be applied during the design, construction, and alteration of buildings and facilities to the extent required by the Architectural Barriers Act of 1968, as amended. Technical…

  17. Surface seismic refraction/reflection measurement determinations of potential site resonances and the areal uniformity of NEHRP site class D in Memphis, Tennessee

    USGS Publications Warehouse

    Williams, R.A.; Wood, S.; Stephenson, W.J.; Odum, J.K.; Meremonte, M.E.; Street, R.; Worley, D.M.

    2003-01-01

    We determined S-wave velocities (Vs) to about 40-m depth at 65 locations in the Memphis-Shelby County, Tennessee, area. The Vs measurements were made using high-resolution seismic refraction and reflection methods on the ground surface. We find a clear difference in the Vs profiles between sites located on the Mississippi River flood plain and those located to the east, mostly covered by loess, in the urban areas of Memphis. The average Vs to 30-m depth at 19 sites on the modern Mississippi River floodplain averages 197 m/s (?? 15 m/s) and places 17 of these sites at the low end of NEHRP soil profile category type D (average Vs 180-360 m/s). The two remaining sites are type E. Vs to 30-m depth at 46 sites in the urban areas east of the modern floodplain are more variable and generally higher than the floodplain sites, averaging about 262 m/s (??45 m/s), still within category D. We often observed the base of the loess as a prominent S-wave reflection and as an increase in Vs to about 500 m/s. Based on the two-way travel time of this reflection, during an earthquake the impedance boundary at the loess base may generate resonances in the 3- to 6-Hz range over many areas of Memphis. Amplitude spectra from four local earthquakes recorded at one site located on loess indicate consistent resonance peaks in the 4.5- to 6.5-Hz range.

  18. Fabrication of magnetic alginate beads with uniform dispersion of CoFe2O4 by the polydopamine surface functionalization for organic pollutants removal

    NASA Astrophysics Data System (ADS)

    Li, Xiaoli; Lu, Haijun; Zhang, Yun; He, Fu; Jing, Lingyun; He, Xinghua

    2016-12-01

    A simple and efficient method for production of magnetic composites by decorating CoFe2O4 with polydopamine (PDA) through oxidative polymerization of dopamine was conducted. Further, magnetic alginate beads with porous structure containing well-dispersed CoFe2O4-PDA were fabricated by ionic crosslinking technology. The resulting SA@CoFe2O4-PDA beads were characterized using scanning electron microscopy, Fourier transform infrared spectrometry, X-ray diffractometer, vibrating sample magnetometer and X-ray photoelectron spectroscopy. Adsorption potential of SA@CoFe2O4-PDA beads for organic dyes including Methylene Blue (MB), Crystal Violet (CV) and Malachite Green (MG) was evaluated. SA@CoFe2O4-PDA beads exhibited excellent adsorption performances due to the composite effect, large surface area and porous structure. Organic dyes could be removed from water solution with high efficiency in a wide pH range of 4.0-9.0. Moreover, it exhibited much higher adsorptivity towards MB and CV with the maximum adsorption capacities of 466.60 and 456.52 mg/g, respectively, which were much higher than that of MG (248.78 mg/g). Ca-electrolyte had obvious adverse effects on MB and CV adsorption than MG. FTIR and XPS demonstrated that carboxylate, catechol, hydroxyl and amine groups might be involved in adsorption of organic dyes. The characteristics of wide pH range, high adsorption capacity and convenient magnetic separation would make SA@CoFe2O4-PDA beads as effective adsorbent for removal of organic dyes from wastewater.

  19. The Effect of Using the Lakatosian Heuristic Method to Teach the Surface Area of a Cone on Students' Achievement According to Bloom's Taxonomy Levels

    ERIC Educational Resources Information Center

    Dimitriou-Hadjichristou, Chrysoula; Ogbonnaya, Ugorji I.

    2015-01-01

    This paper reports a study on the effect of using the Lakatosian heuristic method to teach the surface area of a cone (SAC) on students' achievement according to Bloom's taxonomy levels. Two groups of students (experimental and control) participated in the study. The experimental group (n = 20) was taught using the Lakatosian heuristic method…

  20. Preparation and properties of uniform size colloids

    SciTech Connect

    Matijevic, E. )

    1993-04-01

    The achievements and problems in the preparation of uniform colloids by precipitation from homogeneous electrolyte solutions are reviewed. Specifically, the syntheses of [open quotes]monodispersed[close quotes] particles of simple and mixed compositions as well as of coated and hollow particles of different shapes are described, and the physical and chemical mechanisms of their formation are discussed. 126 refs., 25 figs., 1 tab.

  1. Assessment of AVIRIS Laboratory and In-Flight Uniformity

    NASA Technical Reports Server (NTRS)

    Green, Robert O.

    2004-01-01

    An assessment of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) laboratory and in-flight uniformity is presented in this Slide presentation. The ideal uniform system is described, being a system where every spectrum is intercomparable to every other spectrum. Two types of failures to achieve this uniformity are described. Graphs showing measured spectral upwelling radiance, the expanded spectral convolution, the radiometric error from spectral error, the results from the hyperion Arizaro calibration experiment and a AVIRIS cross-track uniformity are among those presented. The reasons why uniformity matters are presented.

  2. A non-uniform grid for triangular differential quadrature

    NASA Astrophysics Data System (ADS)

    Zhong, HongZhi; Xu, Jia

    2016-12-01

    The triangular differential quadrature method based on a non-uniform grid is proposed in the paper. Explicit expressions of the non-uniform grid point coordinates are given and the weighting coefficients of the triangular differential quadrature method are determined with the aid of area coordinates. Two typical examples are presented to testify the effectiveness of the non-uniform grid. It is shown that rapid convergence is achieved under the non-uniform grid in comparison with those from the uniform grid with the same order of approximation.

  3. CD uniformity control for thick resist process

    NASA Astrophysics Data System (ADS)

    Huang, Chi-hao; Liu, Yu-Lin; Wang, Weihung; Yang, Mars; Yang, Elvis; Yang, T. H.; Chen, K. C.

    2017-03-01

    In order to meet the increasing storage capacity demand and reduce bit cost of NAND flash memories, 3D stacked flash cell array has been proposed. In constructing 3D NAND flash memories, the higher bit number per area is achieved by increasing the number of stacked layers. Thus the so-called "staircase" patterning to form electrical connection between memory cells and word lines has become one of the primarily critical processes in 3D memory manufacture. To provide controllable critical dimension (CD) with good uniformity involving thick photo-resist has also been of particular concern for staircase patterning. The CD uniformity control has been widely investigated with relatively thinner resist associated with resolution limit dimension but thick resist coupling with wider dimension. This study explores CD uniformity control associated with thick photo-resist processing. Several critical parameters including exposure focus, exposure dose, baking condition, pattern size and development recipe, were found to strongly correlate with the thick photo-resist profile accordingly affecting the CD uniformity control. To minimize the within-wafer CD variation, the slightly tapered resist profile is proposed through well tailoring the exposure focus and dose together with optimal development recipe. Great improvements on DCD (ADI CD) and ECD (AEI CD) uniformity as well as line edge roughness were achieved through the optimization of photo resist profile.

  4. Asymptotic analysis of solution to the nonlinear problem of non-stationary heat conductivity of layered anisotropic non-uniform shells at low Biot numbers on the front surfaces

    NASA Astrophysics Data System (ADS)

    Yankovskii, A. P.

    2017-03-01

    The nonlinear problem of non-stationary heat conductivity of the layered anisotropic heat-sensitive shells was formulated taking into account the linear dependence of thermal-physical characteristics of the materials of phase compositions on the temperature. The initial-boundary-value problem is formulated in the dimensionless form, and four small parameters are identified: thermal-physical, characterizing the degree of heat sensitivity of the layer material; geometric, characterizing the relative thickness of the thin-walled structure, and two small Biot numbers on the front surfaces of shells. A sequential recursion of dimensionless equations is carried out, at first, using the thermalphysical small parameter, then, small Biot numbers and, finally, geometrical small parameter. The first type of recursion allowed us to linearize the problem of heat conductivity, and on the basis of two latter types of recursion, the outer asymptotic expansion of solution to the problem of non-stationary heat conductivity of the layered anisotropic non-uniform shells and plates under boundary conditions of the II and III kind and small Biot numbers on the facial surfaces was built, taking into account heat sensitivity of the layer materials. The resulting two-dimensional boundary problems were analyzed, and asymptotic properties of solutions to the heat conductivity problem were studied. The physical explanation was given to some aspects of asymptotic temperature decomposition.

  5. Direct Deposition of Uniform High-κ Dielectrics on Graphene

    PubMed Central

    Zhou, Peng; Yang, Songbo; Sun, Qingqing; Chen, Lin; Wang, Pengfei; Ding, Shijin; Zhang, David Wei

    2014-01-01

    High quality High-κ dielectrics on graphene were achieved by atomic layer deposition directly using remote oxygen plasma surface pretreatment. The uniform coverage on graphene is illustrated by atomic force microscopy and confirmed by high resolution transmission microscopy. The possible surface lattice damage induced by plasma is limited and demonstrated by Raman spectra. The excellent Hall mobility for graphene is maintained at 2.7 × 103 cm2/V·s, which only decreases by 25%. The excellent electrical characteristic of dielectric presents the low leakage current density and high breakdown voltage. Moreover, the technology is compatible with the traditional CMOS process which brings much possibility to future graphene devices. PMID:25264077

  6. 23 CFR 655.604 - Achieving basic uniformity.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... the Highway Safety Program Guideline 21, “Roadway Safety.” Highway planning and research funds and highway related safety grant program funds may be used in statewide or systemwide studies or inventories. Also, metropolitan planning (PL) funds may be used in urbanized areas provided the activity is included...

  7. 23 CFR 655.604 - Achieving basic uniformity.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... the Highway Safety Program Guideline 21, “Roadway Safety.” Highway planning and research funds and highway related safety grant program funds may be used in statewide or systemwide studies or inventories. Also, metropolitan planning (PL) funds may be used in urbanized areas provided the activity is included...

  8. 23 CFR 655.604 - Achieving basic uniformity.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... the Highway Safety Program Guideline 21, “Roadway Safety.” Highway planning and research funds and highway related safety grant program funds may be used in statewide or systemwide studies or inventories. Also, metropolitan planning (PL) funds may be used in urbanized areas provided the activity is included...

  9. 23 CFR 655.604 - Achieving basic uniformity.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... the Highway Safety Program Guideline 21, “Roadway Safety.” Highway planning and research funds and highway related safety grant program funds may be used in statewide or systemwide studies or inventories. Also, metropolitan planning (PL) funds may be used in urbanized areas provided the activity is included...

  10. 23 CFR 655.604 - Achieving basic uniformity.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... the Highway Safety Program Guideline 21, “Roadway Safety.” Highway planning and research funds and highway related safety grant program funds may be used in statewide or systemwide studies or inventories. Also, metropolitan planning (PL) funds may be used in urbanized areas provided the activity is included...

  11. Processing of materials for uniform field emission

    DOEpatents

    Pam, Lawrence S.; Felter, Thomas E.; Talin, Alec; Ohlberg, Douglas; Fox, Ciaran; Han, Sung

    1999-01-01

    This method produces a field emitter material having a uniform electron emitting surface and a low turn-on voltage. Field emitter materials having uniform electron emitting surfaces as large as 1 square meter and turn-on voltages as low as 16V/.mu.m can be produced from films of electron emitting materials such as polycrystalline diamond, diamond-like carbon, graphite and amorphous carbon by the method of the present invention. The process involves conditioning the surface of a field emitter material by applying an electric field to the surface, preferably by scanning the surface of the field emitter material with an electrode maintained at a fixed distance of at least 3 .mu.m above the surface of the field emitter material and at a voltage of at least 500V. In order to enhance the uniformity of electron emission the step of conditioning can be preceeded by ion implanting carbon, nitrogen, argon, oxygen or hydrogen into the surface layers of the field emitter material.

  12. Processing of materials for uniform field emission

    DOEpatents

    Pam, L.S.; Felter, T.E.; Talin, A.; Ohlberg, D.; Fox, C.; Han, S.

    1999-01-12

    This method produces a field emitter material having a uniform electron emitting surface and a low turn-on voltage. Field emitter materials having uniform electron emitting surfaces as large as 1 square meter and turn-on voltages as low as 16V/{micro}m can be produced from films of electron emitting materials such as polycrystalline diamond, diamond-like carbon, graphite and amorphous carbon by the method of the present invention. The process involves conditioning the surface of a field emitter material by applying an electric field to the surface, preferably by scanning the surface of the field emitter material with an electrode maintained at a fixed distance of at least 3 {micro}m above the surface of the field emitter material and at a voltage of at least 500V. In order to enhance the uniformity of electron emission the step of conditioning can be preceded by ion implanting carbon, nitrogen, argon, oxygen or hydrogen into the surface layers of the field emitter material. 2 figs.

  13. Method of Obtaining Uniform Coatings on Graphite

    DOEpatents

    Campbell, I. E.

    1961-04-01

    A method is given for obtaining uniform carbide coatings on graphite bodies. According to the invention a metallic halide in vapor form is passed over the graphite body under such conditions of temperature and pressure that the halide reacts with the graphite to form a coating of the metal carbide on the surface of the graphite.

  14. METHOD OF OBTAINING UNIFORM COATINGS ON GRAPHITE

    DOEpatents

    Campbell, I.E.

    1961-04-01

    A method is given for obtaining uniform carbide coatings on graphite bodies. According to the invention a metallic halide in vapor form is passed over the graphite body under such conditions of temperature and pressure that the halide reacts with the graphite to form a coating of the metal carbide on the surface of the graphite.

  15. Apparatus and method for controlling plating uniformity

    DOEpatents

    Hachman Jr., John T.; Kelly, James J.; West, Alan C.

    2004-10-12

    The use of an insulating shield for improving the current distribution in an electrochemical plating bath is disclosed. Numerical analysis is used to evaluate the influence of shield shape and position on plating uniformity. Simulation results are compared to experimental data for nickel deposition from a nickel--sulfamate bath. The shield is shown to improve the average current density at a plating surface.

  16. Optimal design of optical system for LED road lighting with high illuminance and luminance uniformity.

    PubMed

    Hu, Xiaojia; Qian, Keyuan

    2013-08-20

    A new method is proposed to achieve high illuminance and luminance uniformity of the road surface in LED road lighting. Based on the reflection properties of the road surface, the illuminance and luminance are analyzed simultaneously with the least-square method; meanwhile, energy efficiency and glare requirements are considered. Through the analysis and calculations, the optimal light distribution of a luminaire is obtained, and then a freeform lens with this light distribution is designed. For a 2-lane C1 class road illuminated by LED luminaires mounted with these lenses, the overall illuminance and luminance uniformity on the road surface can reach over 0.9 and 0.85, respectively, and the glare factors less than 10%.

  17. Evaluating uniformity of IR reference sources

    NASA Astrophysics Data System (ADS)

    Barrat, Catherine; Violleau, Sébastien

    2015-10-01

    Infrared reference sources such as blackbodies are used to calibrate and test IR sensors and cameras.. Applications requiring a high thermal uniformity over the emissive surface become more and more frequent compared to the past applications. Among these applications are non uniformity correction of infrared cameras focused at short distance and simultaneous calibration of a set of sensor facing a large area blackbody. Facing these demanding applications requires to accurately measuring thee thermal radiation of each point of the emissive surface of the reference source. The use of an infrared camera for this purpose turns out to be absolutely inefficient since the uniformity off response of this camera is usually worse than the uniformity of thee source to bee measured. Consequently, HGH has developed a testing bench for accurate measurement of uniformity of infrared sources based on a low noise radiometer mounted of translating stages and using an exclusive drift correction method. This bench delivers a reliable thermal map of any kind of infrared reference source.

  18. Surface characterization of an energetic material, pentaerythritoltetranitrate (PETN), having a thin coating achieved through a starved addition microencapsulation technique

    SciTech Connect

    Worley, C.M.

    1986-05-07

    The objective of this research was to: (1) determine the nature of a thin coating on an explosive material which was applied using a starved addition microencapsulation technique, (2) understand the coating/crystal bond, and (3) investigate the wettability/adhesion of plastic/solvent combinations using the coating process. The coating used in this work was a Firestone Plastic Company copolymer (FPC-461) of vinylchloride/trifluorochloroethylene in a 1.5/1.0 weight ratio. The energetic explosive examined was pentaerythritoltetranitrate (PETN). The coating process used was starved addition followed by a solvent evaporation technique. Surface analytical studies, completed for characterization of the coating process, show (1) evidence that the polymer coating is present, but not continuous, over the surface of PETN; (2) the average thickness of the polymer coating is between 16-32 A and greater than 44 A, respectively, for 0.5 and 20 wt % coated PETN; (3) no changes in surface chemistry of the polymer or the explosive material following microencapsulation; and (4) the presence of explosive material on the surface of 0.5 wt % FPC-461 coated explosives. 5 refs., 15 figs., 6 tabs.

  19. Should School Nurses Wear Uniforms?

    ERIC Educational Resources Information Center

    Journal of School Health, 2001

    2001-01-01

    This 1958 paper questions whether school nurses should wear uniforms (specifically, white uniforms). It concludes that white uniforms are often associated with the treatment of ill people, and since many people have a fear reaction to them, they are not necessary and are even undesirable. Since school nurses are school staff members, they should…

  20. Temperature uniformity in hyperthermal tumor therapy

    NASA Technical Reports Server (NTRS)

    Harrison, G. H.; Robinson, J. E.; Samaras, G. M.

    1978-01-01

    Mouse mammary tumors heated by water bath or by microwave-induced hyperthermia exhibit a response that varies sharply with treatment temperature; therefore, uniform heating of the tumor is essential to quantitate the biological response as a function of temperature. C3H tumors implanted on the mouse flank were easily heated to uniformities within 0.1 C by using water baths. Cold spots up to 1 C below the desired treatment temperature were observed in the same tumors implanted on the hind leg. These cold spots were attributed to cooling by major blood vessels near the tumor. In this case temperature uniformity was achieved by the deposition of 2450 MHz microwave energy into the tumor volume by using parallel-opposed applicators.

  1. High-resolution surface charge image achieved by a multiforce sensor based on a quartz tuning fork in electrostatic force microscope

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-yong; Bao, Jian-bin; Zhang, Hong-hai; Guo, Wen-ming

    2002-08-01

    A multiforce sensor was fabricated by attaching a tiny tungsten tip to a tuning fork. By operating an ac modulation bias on the minitip of the needle sensor, we have achieved a dynamic noncontact mode electrostatic force microscope with high spatial resolution. It can utilize the van der Waals force and electrostatic force signals between the microtip and the sample, respectively, to obtain the images of topography and quantitative surface charge density of an open-gate field effect transistor simultaneously.

  2. Uniform quantized electron gas

    NASA Astrophysics Data System (ADS)

    Høye, Johan S.; Lomba, Enrique

    2016-10-01

    In this work we study the correlation energy of the quantized electron gas of uniform density at temperature T  =  0. To do so we utilize methods from classical statistical mechanics. The basis for this is the Feynman path integral for the partition function of quantized systems. With this representation the quantum mechanical problem can be interpreted as, and is equivalent to, a classical polymer problem in four dimensions where the fourth dimension is imaginary time. Thus methods, results, and properties obtained in the statistical mechanics of classical fluids can be utilized. From this viewpoint we recover the well known RPA (random phase approximation). Then to improve it we modify the RPA by requiring the corresponding correlation function to be such that electrons with equal spins can not be on the same position. Numerical evaluations are compared with well known results of a standard parameterization of Monte Carlo correlation energies.

  3. Compact Flyeye concentrator with improved irradiance uniformity on solar cell

    NASA Astrophysics Data System (ADS)

    Zhuang, Zhenfeng; Yu, Feihong

    2013-08-01

    A Flyeye concentrator with improved irradiance distribution on the solar cell in a concentrator photovoltaic system is proposed. This Flyeye concentrator is composed of four surfaces: a refractive surface, mirror surface, freeform surface, and transmissive surface. Based on the principles of geometrical optics, the contours of the proposed Flyeye concentrator are calculated according to Fermat's principle, the edge-ray principle, and the ray reversibility principle without solving partial differential equations or using an optimization algorithm, therefore a slope angle control method is used to construct the freeform surface. The solid model is established by applying a symmetry of revolution around the optical axis. Additionally, the optical performance for the Flyeye concentrator is simulated and analyzed by Monte-Carlo method. Results show that the Flyeye concentrator optical efficiency of >96.2% is achievable with 1333× concentration ratio and ±1.3 deg acceptance angle, and 1.3 low aspect ratio (average thickness to entry aperture diameter ratio). Moreover, comparing the Flyeye concentrator specification to that of the Köhler concentrator and the traditional Fresnel-type concentrator, results indicate that this concentrator has the advantages of improved uniformity, reduced thickness, and increased tolerance to the incident sunlight.

  4. Core-shell magnetite-silica dithiocarbamate-derivatised particles achieve the Water Framework Directive quality criteria for mercury in surface waters.

    PubMed

    Lopes, C B; Figueira, P; Tavares, D S; Lin, Z; Daniel-da-Silva, A L; Duarte, A C; Rocha, J; Trindade, T; Pereira, E

    2013-09-01

    The sorption capacity of nanoporous titanosilicate Engelhard titanosilicate number 4 (ETS-4) and silica-coated magnetite particles derivatised with dithiocarbamate groups towards Hg(II) was evaluated and compared in spiked ultra-pure and spiked surface-river water, for different batch factors. In the former, and using a batch factor of 100 m(3)/kg and an initial Hg(II) concentrations matching the maximum allowed concentration in an effluent discharge, both materials achieve Hg(II) uptake efficiencies in excess of 99 % and a residual metal concentration lower than the guideline value for drinking water quality. For the surface-river water and the same initial concentration, the Hg(II) uptake efficiency of magnetite particles is outstanding, achieving the quality criteria established by the Water Framework Directive (concerning Hg concentration in surface waters) using a batch factor of 50 m(3)/kg, while the efficiency of ETS-4 is significantly inferior. The dissimilar sorbents' Hg(II) removal efficiency is attributed to different uptake mechanisms. This study also highlights the importance of assessing the effective capacity of the sorbents under realistic conditions in order to achieve trustable results.

  5. Modulation of Crystal Surface and Lattice by Doping: Achieving Ultrafast Metal-Ion Insertion in Anatase TiO2.

    PubMed

    Wang, Hsin-Yi; Chen, Han-Yi; Hsu, Ying-Ya; Stimming, Ulrich; Chen, Hao Ming; Liu, Bin

    2016-10-11

    We report that an ultrafast kinetics of reversible metal-ion insertion can be realized in anatase titanium dioxide (TiO2). Niobium ions (Nb5+) were carefully chosen to dope and drive anatase TiO2 into very thin nanosheets standing perpendicularly onto transparent conductive electrode (TCE) and simultaneously construct TiO2 with an ion-conducting surface together with expanded ion diffusion channels, which enabled ultrafast metal ions diffusion across the electrolyte/solid interface and into the bulk of TiO2. To demonstrate the superior metal-ion insertion rate, the electrochromic features induced by ion intercalation were examined, which exhibited the best color switching speed of 4.82 s for coloration and 0.91 s for bleaching among all reported nano-sized TiO2 devices. When performed as the anode for the secondary battery, the modified TiO2 was capable to deliver a highly reversible capacity of 61.2 mAh g-1 at an ultrahigh specific current rate of 60 C (10.2 A g-1). This fast metal-ion insertion behavior was systematically investigated by the well-controlled electrochemical approaches, which quantitatively revealed both the enhanced surface kinetics and bulk ion diffusion rate. Our study could provide a facile methodology to modulate the ion diffusion kinetics for metal oxides.

  6. Design of 360° moveable and uniform feeding system

    NASA Astrophysics Data System (ADS)

    Zhang, Lizhen; Ma, Dihong; Yang, Mengmeng; Hu, Qingsong

    2017-06-01

    In order to solve the feeding problem in shrimp aquaculture which is high labor intensity, low automation and non-uniform feed distribution, a 360° moveable and uniform feeding system was proposed. The feeding system uses turbine worm mechanism to realize the quantitative feeding, and the turbine is conveying plate which can adjust the conveying speed according to catamaran’s cruise speed. Casting plate can achieve 360° uniform cast feed. A catamaran is used as carrier platform for feeding machine, and BeiDou satellite positioning system installed on the catamaran helps to automatic cruise. So the moveable and uniform of shrimp pond feeding can be realized in this way.

  7. Optimization of deposition uniformity for large-aperture National Ignition Facility substrates in a planetary rotation system.

    PubMed

    Oliver, James B; Talbot, David

    2006-05-01

    Multilayer coatings on large substrates with increasingly complex spectral requirements are essential for a number of optical systems, placing stringent requirements on the error tolerances of individual layers. Each layer must be deposited quite uniformly over the entire substrate surface since any nonuniformity will add to the layer-thickness error level achieved. A deposition system containing a planetary rotation system with stationary uniformity masking is modeled, with refinements of the planetary gearing, source placement, and uniformity mask shape being utilized to achieve an optimal configuration. The impact of improper planetary gearing is demonstrated theoretically, as well as experimentally, providing more comprehensive requirements than simply avoiding repetition of previous paths through the vapor plume, until all possible combinations of gear teeth have been used. Deposition efficiency and the impact of changing vapor plume conditions on the uniformity achieved are used to validate improved source placement. Uniformity measurements performed on a mapping laser photometer demonstrate nonuniformities of less than 0.5% for 0.75 m optics in a 72 in. (1.8 m) coating chamber.

  8. Elimination of strength degrading effects caused by surface microdefect: A prevention achieved by silicon nanotexturing to avoid catastrophic brittle fracture

    PubMed Central

    Kashyap, Kunal; Kumar, Amarendra; Huang, Chuan-Torng; Lin, Yu-Yun; Hou, Max T.; Andrew Yeh, J.

    2015-01-01

    The unavoidable occurrence of microdefects in silicon wafers increase the probability of catastrophic fracture of silicon-based devices, thus highlighting the need for a strengthening mechanism to minimize fractures resulting from defects. In this study, a novel mechanism for manufacturing silicon wafers was engineered based on nanoscale reinforcement through surface nanotexturing. Because of nanotexturing, different defect depths synthetically emulated as V-notches, demonstrated a bending strength enhancement by factors of 2.5, 3.2, and 6 for 2-, 7-, and 14-μm-deep V-notches, respectively. A very large increase in the number of fragments observed during silicon fracturing was also indicative of the strengthening effect. Nanotextures surrounding the V-notch reduced the stress concentration factor at the notch tip and saturated as the nanotexture depth approached 1.5 times the V-notch depth. The stress reduction at the V-notch tip measured by micro-Raman spectroscopy revealed that nanotextures reduced the effective depth of the defect. Therefore, the nanotextured samples were able to sustain a larger fracture force. The enhancement in Weibull modulus, along with an increase in bending strength in the nanotextured samples compared to polished single-crystal silicon samples, demonstrated the reliability of the strengthening method. These results suggest that this method may be suitable for industrial implementation. PMID:26040924

  9. Elimination of strength degrading effects caused by surface microdefect: A prevention achieved by silicon nanotexturing to avoid catastrophic brittle fracture

    NASA Astrophysics Data System (ADS)

    Kashyap, Kunal; Kumar, Amarendra; Huang, Chuan-Torng; Lin, Yu-Yun; Hou, Max T.; Andrew Yeh, J.

    2015-06-01

    The unavoidable occurrence of microdefects in silicon wafers increase the probability of catastrophic fracture of silicon-based devices, thus highlighting the need for a strengthening mechanism to minimize fractures resulting from defects. In this study, a novel mechanism for manufacturing silicon wafers was engineered based on nanoscale reinforcement through surface nanotexturing. Because of nanotexturing, different defect depths synthetically emulated as V-notches, demonstrated a bending strength enhancement by factors of 2.5, 3.2, and 6 for 2-, 7-, and 14-μm-deep V-notches, respectively. A very large increase in the number of fragments observed during silicon fracturing was also indicative of the strengthening effect. Nanotextures surrounding the V-notch reduced the stress concentration factor at the notch tip and saturated as the nanotexture depth approached 1.5 times the V-notch depth. The stress reduction at the V-notch tip measured by micro-Raman spectroscopy revealed that nanotextures reduced the effective depth of the defect. Therefore, the nanotextured samples were able to sustain a larger fracture force. The enhancement in Weibull modulus, along with an increase in bending strength in the nanotextured samples compared to polished single-crystal silicon samples, demonstrated the reliability of the strengthening method. These results suggest that this method may be suitable for industrial implementation.

  10. The optimal design of TIR lens for improving LED illumination uniformity and efficiency

    NASA Astrophysics Data System (ADS)

    Zhen, Yankun; Jia, Zhenan; Zhang, Wenzi

    2008-03-01

    With the development of LED technology, LED will potentially replace the traditional light source for its cost and size advantages, especially in the micro-projection system. And since the illumination uniformity and efficiency on spatial light modulators (SLM) are two important factors in evaluating the performance of micro-projection system, tapered light pipe (TLP) and square compound parabolic concentrator (SCPC) are often used as beam shaper in LED-based micro projection system to provide SLM with uniform and efficient illumination. In this paper, in order to overcome the disadvantage of insufficient compactness induced by the working length of TLP or SCPC for the illumination system, a total internal reflection (TIR) lens with rotated and faceted structure is designed with an optimization method to couple and transfer most of the light emitted from LED into a rectangular target plane (RTP) representing SLM. The TIR lens has six surfaces controlled by 17 dimensional parameters and is designed by optimization of dimensional parameters with generic algorithms. In order to provide RTP in fixed position with satisfied illumination uniformity and efficiency, the illumination uniformity and efficiency on RTP are taken into account in the merit function for the optimization process. In Tracepro program, the simulation result of the LED illumination system with the optimized TIR lens shows that the illumination efficiency and uniformity has respectively achieved to 61.9%, 76% with considering the limitation angle of light (15°).

  11. Predicting ion flux uniformity at the ion extraction plate in a 3D ICP reactor

    NASA Astrophysics Data System (ADS)

    Roy, Abhra; Bhoj, Ananth

    2016-09-01

    In order to achieve better control in processing the wafer surface, the ion fluxes in a remote plasma system are often focused through one or more ion extraction plates between the main plasma chamber and the downstream wafer plane. The ion extraction plates are typically of showerhead pattern with multiple holes. The focus of this particular study is to predict the ion flux uniformity over the ion extraction plate for a full 3D inductively coupled discharge reactor model using Argon chemistry. We will use the commercial modeling tool, CFD-ACE +, which can address such a process involving gas flow, heat transfer, plasma physics, reaction chemistry and electromagnetics in a coupled fashion. The plasma characteristics in the chamber and uniformity of the ion fluxes at ion extraction plate are discussed. Parametric studies varying the geometrical dimensions and process conditions to determine the effect on ion flux uniformity are presented. The showerhead-like ion extraction plate will be modeled as a porous media with a specified porosity. Further, a spatially varying porosity of the ion extraction plate is used to simulate ion recombination in order to reduce the ion flux non-uniformity. The goal is to optimize the system maximizing the ion flux while maintaining the uniformity.

  12. A Fast Spherical Filter with Uniform Resolution

    NASA Astrophysics Data System (ADS)

    Jakob-Chien, Rüdiger; Alpert, Bradley K.

    1997-09-01

    This paper introduces a fast algorithm for obtaining a uniform resolution representation of a function known at a latitude-longitude grid on the surface of a sphere, equivalent to a triangular, isotropic truncation of the spherical harmonic coefficients for the function. The proposedspectral truncation method,which is based on the fast multipole method and the fast Fourier transform, projects the function to a space with uniform resolution while avoiding surface harmonic transformations. The method requiresO(N2logN) operations forO(N2) grid points, as opposed toO(N3) operations for the standard spectral transform method, providing a reduced-complexity spectral method obviating the pole problem in the integration of time-dependent partial differential equations on the sphere. The filter's performance is demonstrated with numerical examples.

  13. School Uniforms: Esprit de Corps.

    ERIC Educational Resources Information Center

    Ryan, Rosemary P.; Ryan, Thomas E.

    1998-01-01

    The benefits of school uniforms far outweigh their short-term costs. School uniforms not only keep students safe, but they increase their self-esteem, promote a more positive attitude toward school, lead to improved student behavior, and help blur social-class distinctions. Students are allowed to wear their own political or religious messages,…

  14. Non-Uniform Thickness Electroactive Device

    NASA Technical Reports Server (NTRS)

    Su, Ji (Inventor); Harrison, Joycelyn S. (Inventor)

    2006-01-01

    An electroactive device comprises at least two layers of material, wherein at least one layer is an electroactive material and wherein at least one layer is of non-uniform thickness. The device can be produced in various sizes, ranging from large structural actuators to microscale or nanoscale devices. The applied voltage to the device in combination with the non-uniform thickness of at least one of the layers (electroactive and/or non-electroactive) controls the contour of the actuated device. The effective electric field is a mathematical function of the local layer thickness. Therefore, the local strain and the local bending/ torsion curvature are also a mathematical function of the local thickness. Hence the thinnest portion of the actuator offers the largest bending and/or torsion response. Tailoring of the layer thicknesses can enable complex motions to be achieved.

  15. Uniform acceleration in general relativity

    NASA Astrophysics Data System (ADS)

    Friedman, Yaakov; Scarr, Tzvi

    2015-10-01

    We extend de la Fuente and Romero's (Gen Relativ Gravit 47:33, 2015) defining equation for uniform acceleration in a general curved spacetime from linear acceleration to the full Lorentz covariant uniform acceleration. In a flat spacetime background, we have explicit solutions. We use generalized Fermi-Walker transport to parallel transport the Frenet basis along the trajectory. In flat spacetime, we obtain velocity and acceleration transformations from a uniformly accelerated system to an inertial system. We obtain the time dilation between accelerated clocks. We apply our acceleration transformations to the motion of a charged particle in a constant electromagnetic field and recover the Lorentz-Abraham-Dirac equation.

  16. Instrumentation For Detector Spectral / Spatial Uniformity Measurements

    NASA Astrophysics Data System (ADS)

    Craft, Ronald W.; Bronson, Robert M.

    1989-09-01

    The information presented in this report describes an instrument which is used for precision measurements of detector spectral response and spatial response. Emphasis will be placed on detector spatial uniformity measurements. To allow spatial uniformity testing at selected wavelengths, an instrument was designed by applying existing spectral response instrumentation technology with the addition of special exit optics, a dual axis motorized positioning table, and supporting software. Supporting components consisted of a computer controlled radiometer and a monochromator with a high intensity light source attached. Spectral response is determined by measuring the wavelength response photosensitivity of a stationary specimen to the irradiance of a calibrated monochromatic light source over the wavelength range of interest at evenly spaced intervals. Data is presented in a pictorial format by graphing the RESPONSE versus the WAVELENGTH. Detector spatial response is determined by measuring the variation in photosensitivity over the surface of the test detector by moving the detector in an X,Y grid at evenly spaced intervals under a small monochromatic spot of light. Several versions of the instrument were built and test results are provided which represent data from the spatial uniformity testing of Ge, PbS, and PbSe detectors. Data acquired is presented as a 3-Dimensional surface map by plotting the RESPONSE versus the X POSITION versus the Y POSITION.

  17. The Uniformly Accelerated Reference Frame

    ERIC Educational Resources Information Center

    Hamilton, J. Dwayne

    1978-01-01

    The observations that would be made by a uniformly accelerated observer, including the observer's event horizon, the variation of clock rates with position, and the effects of following a freely falling object are considered in detail. (SL)

  18. Are School Uniforms a Good Fit? Results from the ECLS-K and the NELS

    ERIC Educational Resources Information Center

    Yeung, Ryan

    2009-01-01

    One of the most common proposals put forth for reform of the American system of education is to require school uniforms. Proponents argue that uniforms can make schools safer and also improve school attendance and increase student achievement. Opponents contend that uniforms have not been proven to work and may be an infringement on the freedom of…

  19. Are School Uniforms a Good Fit? Results from the ECLS-K and the NELS

    ERIC Educational Resources Information Center

    Yeung, Ryan

    2009-01-01

    One of the most common proposals put forth for reform of the American system of education is to require school uniforms. Proponents argue that uniforms can make schools safer and also improve school attendance and increase student achievement. Opponents contend that uniforms have not been proven to work and may be an infringement on the freedom of…

  20. Fabrication of Uniform Nanoporous Oxide Layers on Long Cylindrical Zircaloy Tubes by Anodization Using Multi-Counter Electrodes.

    PubMed

    Park, Yang Jeong; Kim, Jung Woo; Ali, Ghafar; Kim, Hyun Jin; Addad, Yacine; Cho, Sung Oh

    2017-12-01

    We have presented a method to prepare a uniform anodic nanoporous oxide film on the surface of a cylindrical zircaloy (Zr) tube. The distribution of the electric field around the Zr tube determines the distribution of the thickness of the anodic nanoporous oxide film. The electric field generated when a cylindrical Zr tube is electrochemically anodized was simulated by using commercial code COMSOL. When four Pt wires were used as counter electrodes, a uniform electric field was achieved with minimal use of Pt. Based on the simulation results, a cylindrical Zr tube was anodized and the distribution of the thickness of the anodic nanoporous oxide layer was measured by FESEM. Also, mass production of uniform nanoporous anodic oxide films was possible by symmetrically arranging the zircaloy tubes and Pt wires.

  1. Fabrication of Uniform Nanoporous Oxide Layers on Long Cylindrical Zircaloy Tubes by Anodization Using Multi-Counter Electrodes

    NASA Astrophysics Data System (ADS)

    Park, Yang Jeong; Kim, Jung Woo; Ali, Ghafar; Kim, Hyun Jin; Addad, Yacine; Cho, Sung Oh

    2017-01-01

    We have presented a method to prepare a uniform anodic nanoporous oxide film on the surface of a cylindrical zircaloy (Zr) tube. The distribution of the electric field around the Zr tube determines the distribution of the thickness of the anodic nanoporous oxide film. The electric field generated when a cylindrical Zr tube is electrochemically anodized was simulated by using commercial code COMSOL. When four Pt wires were used as counter electrodes, a uniform electric field was achieved with minimal use of Pt. Based on the simulation results, a cylindrical Zr tube was anodized and the distribution of the thickness of the anodic nanoporous oxide layer was measured by FESEM. Also, mass production of uniform nanoporous anodic oxide films was possible by symmetrically arranging the zircaloy tubes and Pt wires.

  2. Dual-Electrode CMUT With Non-Uniform Membranes for High Electromechanical Coupling Coefficient and High Bandwidth Operation

    PubMed Central

    Guldiken, Rasim O.; Zahorian, Jaime; Yamaner, F. Y.; Degertekin, F. L.

    2010-01-01

    In this paper, we report measurement results on dual-electrode CMUT demonstrating electromechanical coupling coefficient (k2) of 0.82 at 90% of collapse voltage as well as 136% 3 dB one-way fractional bandwidth at the transducer surface around the design frequency of 8 MHz. These results are within 5% of the predictions of the finite element simulations. The large bandwidth is achieved mainly by utilizing a non-uniform membrane, introducing center mass to the design, whereas the dual-electrode structure provides high coupling coefficient in a large dc bias range without collapsing the membrane. In addition, the non-uniform membrane structure improves the transmit sensitivity of the dual-electrode CMUT by about 2dB as compared with a dual electrode CMUT with uniform membrane. PMID:19574135

  3. Dual-electrode CMUT with non-uniform membranes for high electromechanical coupling coefficient and high bandwidth operation.

    PubMed

    Guldiken, Rasim O; Zahorian, Jaime; Yamaner, F Y; Degertekin, F Levent

    2009-06-01

    In this paper, we report measurement results on dual-electrode CMUT demonstrating electromechanical coupling coefficient (k(2)) of 0.82 at 90% of collapse voltage as well as 136% 3 dB one-way fractional bandwidth at the transducer surface around the design frequency of 8 MHz. These results are within 5% of the predictions of the finite element simulations. The large bandwidth is achieved mainly by utilizing a non-uniform membrane, introducing center mass to the design, whereas the dual-electrode structure provides high coupling coefficient in a large dc bias range without collapsing the membrane. In addition, the non-uniform membrane structure improves the transmit sensitivity of the dual-electrode CMUT by about 2dB as compared with a dual electrode CMUT with uniform membrane.

  4. Bicubic uniform B-spline wavefront fitting technology applied in computer-generated holograms

    NASA Astrophysics Data System (ADS)

    Cao, Hui; Sun, Jun-qiang; Chen, Guo-jie

    2006-02-01

    This paper presented a bicubic uniform B-spline wavefront fitting technology to figure out the analytical expression for object wavefront used in Computer-Generated Holograms (CGHs). In many cases, to decrease the difficulty of optical processing, off-axis CGHs rather than complex aspherical surface elements are used in modern advanced military optical systems. In order to design and fabricate off-axis CGH, we have to fit out the analytical expression for object wavefront. Zernike Polynomial is competent for fitting wavefront of centrosymmetric optical systems, but not for axisymmetrical optical systems. Although adopting high-degree polynomials fitting method would achieve higher fitting precision in all fitting nodes, the greatest shortcoming of this method is that any departure from the fitting nodes would result in great fitting error, which is so-called pulsation phenomenon. Furthermore, high-degree polynomials fitting method would increase the calculation time in coding computer-generated hologram and solving basic equation. Basing on the basis function of cubic uniform B-spline and the character mesh of bicubic uniform B-spline wavefront, bicubic uniform B-spline wavefront are described as the product of a series of matrices. Employing standard MATLAB routines, four kinds of different analytical expressions for object wavefront are fitted out by bicubic uniform B-spline as well as high-degree polynomials. Calculation results indicate that, compared with high-degree polynomials, bicubic uniform B-spline is a more competitive method to fit out the analytical expression for object wavefront used in off-axis CGH, for its higher fitting precision and C2 continuity.

  5. Highly Stable Silver Nanoplates for Surface Plasmon Resonance Biosensing

    SciTech Connect

    Gao, Chuanbo; Lu, Zhenda; Chi, Miaofang; Liu, ying; Cheng, Quan; Yin, Yadong

    2012-01-01

    An SPR biosensor was developed by employing highly stable Au-protected Ag nanoplates (NP) as enhancers (see picture). Superior performance was achieved by depositing a thin and uniform coating of Au on the Ag surface while minimizing disruptive galvanic replacement and retaining the strong surface plasmon resonance (SPR) of the silver nanoplates.

  6. Growth of ultra-uniform graphene using a Ni/W bilayer metal catalyst

    SciTech Connect

    Yang, Jae Hoon; Hwang, Jae Seok; Yang, Hyoung Woo; Kang, Dae Joon; Jang, A-Rang; Shin, Hyeon Suk; Jang, Jae-Eun

    2015-01-26

    We investigated a bilayer catalyst system consisting of polycrystalline Ni and W films for growing mono-layer graphene over large areas. Highly uniform graphene was grown on Ni/W bilayer film with 100% coverage. The graphene grown on Ni/W bilayer film and transferred onto an insulating substrate exhibited average hole and electron mobilities of 727 and 340 cm{sup 2}V{sup −1}s{sup −1}, respectively. A probable growth mechanism is proposed based on X-ray diffractometry and transmission electron microscopy, which suggests that the reaction between diffused carbon and tungsten atoms results in formation of tungsten carbides. This reaction allows the control of carbon precipitation and prevents the growth of non-uniform multilayer graphene on the Ni surface; this has not been straightforwardly achieved before. These results could be of importance in better understanding mono-layer graphene growth, and suggest a facile fabrication route for electronic applications.

  7. Uniform biodegradable microparticle systems for controlled release

    PubMed Central

    Xia, Yujie; Pack, Daniel W.

    2014-01-01

    Drug delivery methods can impact efficacy as much as the nature of the drug itself. Microparticles made of biodegradable polymers such as poly(D,L-lactide-co-glycolide) and poly(lactic acid) (PLA) have been studied extensively for controlled release of diverse drugs. By using a modified solvent extraction/evaporation method called precision particle fabrication (PPF), uniform microparticles such as single-wall microspheres, double-wall microspheres and liquid-core microcapsules have been fabricated with precise control of their geometric structures. By producing particles of uniform size, which has crucial impact on drug release behaviors, PPF-fabricated microparticles provide unique insights about drug release mechanism. Using small-molecule and macromolecule model drugs, our group demonstrated that physicochemical properties of the polymers and drugs and structural properties of the matrix can greatly impact drug distribution within microparticles, particle erosion and drug release rates. By careful selection of particle size and shell thickness, uniform microparticles can achieve “zero-order”, pulsatile or tandem release of drugs. PMID:12106984

  8. Some methods for achieving more efficient performance of fuel assemblies

    NASA Astrophysics Data System (ADS)

    Boltenko, E. A.

    2014-07-01

    More efficient operation of reactor plant fuel assemblies can be achieved through the use of new technical solutions aimed at obtaining more uniform distribution of coolant over the fuel assembly section, more intense heat removal on convex heat-transfer surfaces, and higher values of departure from nucleate boiling ratio (DNBR). Technical solutions using which it is possible to obtain more intense heat removal on convex heat-transfer surfaces and higher DNBR values in reactor plant fuel assemblies are considered. An alternative heat removal arrangement is described using which it is possible to obtain a significantly higher power density in a reactor plant and essentially lower maximal fuel rod temperature.

  9. Design and testing of a uniformly solar energy TIR-R concentration lenses for HCPV systems.

    PubMed

    Shen, S C; Chang, S J; Yeh, C Y; Teng, P C

    2013-11-04

    In this paper, total internal reflection-refraction (TIR-R) concentration (U-TIR-R-C) lens module were designed for uniformity using the energy configuration method to eliminate hot spots on the surface of solar cell and increase conversion efficiency. The design of most current solar concentrators emphasizes the high-power concentration of solar energy, however neglects the conversion inefficiency resulting from hot spots generated by uneven distributions of solar energy concentrated on solar cells. The energy configuration method proposed in this study employs the concept of ray tracing to uniformly distribute solar energy to solar cells through a U-TIR-R-C lens module. The U-TIR-R-C lens module adopted in this study possessed a 76-mm diameter, a 41-mm thickness, concentration ratio of 1134 Suns, 82.6% optical efficiency, and 94.7% uniformity. The experiments demonstrated that the U-TIR-R-C lens module reduced the core temperature of the solar cell from 108 °C to 69 °C and the overall temperature difference from 45 °C to 10 °C, and effectively relative increased the conversion efficiency by approximately 3.8%. Therefore, the U-TIR-R-C lens module designed can effectively concentrate a large area of sunlight onto a small solar cell, and the concentrated solar energy can be evenly distributed in the solar cell to achieve uniform irradiance and effectively eliminate hot spots.

  10. Interactions between uniformly magnetized spheres

    NASA Astrophysics Data System (ADS)

    Edwards, Boyd F.; Riffe, D. M.; Ji, Jeong-Young; Booth, William A.

    2017-02-01

    We use simple symmetry arguments suitable for undergraduate students to demonstrate that the magnetic energy, forces, and torques between two uniformly magnetized spheres are identical to those between two point magnetic dipoles. These arguments exploit the equivalence of the field outside of a uniformly magnetized sphere with that of a point magnetic dipole, and pertain to spheres of arbitrary sizes, positions, and magnetizations. The point dipole/sphere equivalence for magnetic interactions may be useful in teaching and research, where dipolar approximations for uniformly magnetized spheres can now be considered to be exact. The work was originally motivated by interest in the interactions between collections of small neodymium magnetic spheres used as desk toys.

  11. Surface plasmon wave adapter designed with transformation optics.

    PubMed

    Zhang, Jingjing; Xiao, Sanshui; Wubs, Martijn; Mortensen, Niels Asger

    2011-06-28

    On the basis of transformation optics, we propose the design of a surface plasmon wave adapter which confines surface plasmon waves on non-uniform metal surfaces and enables adiabatic mode transformation of surface plasmon polaritons with very short tapers. This adapter can be simply achieved with homogeneous anisotropic naturally occurring materials or subwavelength grating-structured dielectric materials. Full wave simulations based on a finite-element method have been performed to validate our proposal.

  12. Uniform Tests of File Converters Using Unit Cubes

    DTIC Science & Technology

    2015-03-01

    1,000,000,000 mm3. The second part would be to test each face of the cube using the rtarea command, which finds the exposed surface area of all of the...Uniform Tests of File Converters Using Unit Cubes by Steven J Nichols ARL-CR-0770 March 2015 Under contract...March 2015 Uniform Tests of File Converters Using Unit Cubes Steven J Nichols Survivability/Lethality Analysis Directorate, ARL

  13. Development of a novel device for applying uniform doses of electron beam irradiation on carcasses.

    PubMed

    Maxim, Joseph E; Neal, Jack A; Castillo, Alejandro

    2014-01-01

    The Maxim's Electron Scatter Chamber (Maxim Chamber) was developed to obtain uniform dose distribution when applying electron beam (e-beam) irradiation to materials of irregular surface. This was achieved by placing a stainless steel mesh surrounding a cylindrical area where the target sample was placed. Upon contact with the mesh, electrons scatter and are directed onto the target from multiple angles, eliminating the e-beam linearity and resulting in a uniform dose distribution over the target surface. The effect of irradiation in the Maxim Chamber on dose distribution and pathogen reduction was tested on rabbit carcasses to simulate other larger carcasses. The dose uniformity ratio (DUR) on the rabbit carcasses was 1.8, indicating an acceptable dose distribution. On inoculated carcasses, this treatment reduced Escherichia coli O157:H7 by >5 log cycles. These results indicate that carcass irradiation using e-beam is feasible using the Maxim's electron scattering chamber. Appropriate adjustments will be further needed for commercial application on beef and other animal carcasses.

  14. Wave-current interaction, experiments with controlled uniform shear

    NASA Astrophysics Data System (ADS)

    Simon, Bruno; Touboul, Julien; Rey, Vincent

    2016-04-01

    Vertically varying currents have a non negligible impact on the propagation of waves. Even though the analytical aspect of the interaction between wave and sheared current is being an active subject of research, experimental data remain rare. Here, the effects of a uniformly shear were investigated in the 10 m long by 0.3 m wide wave flume of the Université de Toulon, France. The main difficulty of the study was to produce several conditions of current with constant shear (du/dz = cst) that would persist along the channel. This was achieved by using curved wire screens upstream the channel (Dunn and Tavoularis, 2007). The geometry and properties of the screens were adjusted to deflect the streamline towards the channel bed or the free surface in order to change the velocity profile. The study focused on regular wave propagating against the current for several wave frequencies and amplitudes. Properties of the free surface and flow velocity are discussed for current with positive and negative shear in order to quantify the influence of the current on the waves. ACKNOWLEDGEMENTS The DGA (Direction Générale de l'Armement, France) is acknowledged for its financial support through the ANR grant N° ANR-13-ASTR-0007.

  15. Achieving scale-independent land-surface flux estimates - Application of the Multiscale Parameter Regionalization (MPR) to the Noah-MP land-surface model across the contiguous USA

    NASA Astrophysics Data System (ADS)

    Thober, S.; Mizukami, N.; Samaniego, L. E.; Attinger, S.; Clark, M. P.; Cuntz, M.

    2016-12-01

    classical averaging operators used in MPR. This allows us to identify appropriate scalings for parameters that have not been investigated in MPR so far (e.g., maximum carboxylation rate). Using MPR for Noah-MP provides a considerable improvement of the physical consistency that we expect to be achievable also in other land-surface schemes.

  16. Mass-transport-controlled, large-area, uniform deposition of carbon nanofibers and their application in gas diffusion layers of fuel cells.

    PubMed

    Tang, Xian; Xie, Zhiyong; Huang, Qizhong; Chen, Guofen; Hou, Ming; Yi, Baolian

    2015-05-07

    The effect of mass transport on the growth characteristics of large-area vapor-grown carbon nanofibers (CNFs) was investigated by adjusting the substrate deposition angle (α). The catalyst precursor solution was coated onto one side of a 2D porous carbon paper substrate via a decal printing method. The results showed that the CNFs were grown on only one side of the substrate and α was found to significantly affect the growth uniformity. At α = 0°, the growth thickness, the density, the microstructure and the yield of the CNF film were uniform across the substrate surface, whereas the growth uniformity decreased with increasing α, suggesting that the large-area CNF deposition processes were mass-transport-controlled. Computational fluid dynamics simulations of the gas diffusion processes revealed the homogeneous distributions of the carbon-source-gas concentration, pressure, and velocity near the substrate surface at α = 0°, which were the important factors in achieving the mass-transport-limited uniform CNF growth. The homogeneity of the field distributions decreased with increasing α, in accordance with the variation in the growth uniformity with α. When used as a micro-porous layer, the uniform CNF film enabled higher proton exchange membrane fuel cell performance in comparison with commercial carbon black by virtue of its improved electronic and mass-transport properties confirmed by the electrochemical impedance spectroscopy results.

  17. Risks relating to posterior 2-portal arthroscopic subtalar arthrodesis and articular surfaces abrasion quality achievable with these approaches: a cadaver study.

    PubMed

    Mouilhade, F; Oger, P; Roussignol, X; Boisrenoult, P; Sfez, J; Duparc, F

    2011-06-01

    Many techniques for arthroscopic subtalar arthrodesis have been described since 1985. The procedure can be challenging because posterior and anterior portals are used conjointly with distraction. A posterior 2-portal approach was described in 2000. The goal of this study was to evaluate the quality of the freshening that can be achieved in the posterior subtalar joint using this approach. Does a posterior 2-portal approach allow for a complete freshening of the posterior subtalar joint? Freshening was performed through an arthroscopic posterior 2-portal approach on 10 cadavers. The quality of bone freshening and proximity of the neurovascular structures to the posterior portals were subsequently evaluated by dissection. There was one partial laceration of the sural nerve. The posteromedial portal was 6.8mm (95% CI: 4.4 to 9.2) away from the posterior tibial vascular pedicle. The entire talar and calcaneal articular surfaces of the posterior subtalar joint were freshened. In eight of 10 cases (95% CI: 48 to 95%), the posteromedial process of the talus prevented contact between fragments. This study showed that the entire posterior subtalar joint can be freshened through an arthroscopic posterior 2-portal approach with little morbidity. Level IV. Copyright © 2011 Elsevier Masson SAS. All rights reserved.

  18. Uniform peanut performance test 2013

    USDA-ARS?s Scientific Manuscript database

    The Uniform Peanut Performance Tests (UPPT) are designed to evaluate the commercial potential of advanced breeding peanut lines not formally released. The tests are performed in ten locations across the peanut production belt. In this study, 2 controls and 13 entries were evaluated at 9 locations....

  19. Trying Uniforms on for Size.

    ERIC Educational Resources Information Center

    Paliokas, Kathleen L.; And Others

    1996-01-01

    Public school uniforms are a recent development. Legal trends suggest that the courts are willing to defer to school authorities regarding dress codes--provided a clear link is established between the dress regulations and furtherance of the educational mission. Lists a range of options for a dress-code policy and how each of the available options…

  20. Trying Uniforms on for Size.

    ERIC Educational Resources Information Center

    Paliokas, Kathleen L.; And Others

    1996-01-01

    Public school uniforms are a recent development. Legal trends suggest that the courts are willing to defer to school authorities regarding dress codes--provided a clear link is established between the dress regulations and furtherance of the educational mission. Lists a range of options for a dress-code policy and how each of the available options…

  1. Uniform peanut performance test 2015

    USDA-ARS?s Scientific Manuscript database

    The Uniform Peanut Performance Tests (UPPT) are designed to evaluate the commercial potential of advanced breeding peanut lines not formally released. The tests are performed in ten locations across the peanut production belt. In this study, 2 controls and 13 entries were evaluated at 9 locations....

  2. School Uniforms: Guidelines for Principals.

    ERIC Educational Resources Information Center

    Essex, Nathan L.

    2001-01-01

    Principals desiring to develop a school-uniform policy should involve parents, teachers, community leaders, and student representatives; beware restrictions on religious and political expression; provide flexibility and assistance for low-income families; implement a pilot program; align the policy with school-safety issues; and consider legal…

  3. Uniform Peanut Performance Tests 2009

    USDA-ARS?s Scientific Manuscript database

    The Uniform Peanut Performance Tests (UPPT) are designed to evaluate the commercial potential of advanced breeding peanut lines not formally released. The tests are performed in ten locations across the peanut production belt. In this study, there were 2 controls, 3 Florida lines, 6 Georgia lines,...

  4. Uniform Peanut Performance Tests 2007

    USDA-ARS?s Scientific Manuscript database

    The Uniform Peanut Performance Tests (UPPT) are designed to evaluate the commercial potential of advanced breeding peanut lines not formally released. The tests are performed in ten locations across the peanut production belt. In this study, there were 2 controls, 3 Florida lines, 7 Georgia lines,...

  5. Uniform Peanut Performance Tests 2010

    USDA-ARS?s Scientific Manuscript database

    The Uniform Peanut Performance Tests (UPPT) are designed to evaluate the commercial potential of advanced breeding peanut lines not formally released. The tests are performed in ten locations across the peanut production belt. In this study, there were 2 controls, 3 Florida lines, 4 Georgia lines,...

  6. Uniform Peanut Performance Tests 2011

    USDA-ARS?s Scientific Manuscript database

    The Uniform Peanut Performance Tests (UPPT) are designed to evaluate the commercial potential of advanced breeding peanut lines not formally released. The tests are performed in ten locations across the peanut production belt. In this study, there were 2 controls, 3 Florida lines, 3 Georgia lines,...

  7. Uniform Peanut Performance Tests 2008

    USDA-ARS?s Scientific Manuscript database

    The Uniform Peanut Performance Tests (UPPT) are designed to evaluate the commercial potential of advanced breeding peanut lines not formally released. The tests are performed in ten locations across the peanut production belt. In this study, there were 2 controls, 3 Florida lines, 6 Georgia lines,...

  8. Uniform Peanut Performance Tests 2012

    USDA-ARS?s Scientific Manuscript database

    The Uniform Peanut Performance Tests (UPPT) were established in 1973 through an informal arrangement among cooperating scientists involving seven major peanut-producing states. In 1995, plant material transfer agreements were also accepted among all cooperators in the UPPT. The year 2012 completed...

  9. Effects of Lambertian sources design on uniformity and measurements

    NASA Astrophysics Data System (ADS)

    Cariou, Nadine; Durell, Chris; McKee, Greg; Wilks, Dylan; Glastre, Wilfried

    2014-10-01

    Integrating sphere (IS) based uniform sources are a primary tool for ground based calibration, characterization and testing of flight radiometric equipment. The idea of a Lambertian field of energy is a very useful tool in radiometric testing, but this concept is being checked in many ways by newly lowered uncertainty goals. At an uncertainty goal of 2% one needs to assess carefully uniformity in addition to calibration uncertainties, as even sources with a 0.5% uniformity are now substantial proportions of uncertainty budgets. The paper explores integrating sphere design options for achieving 99.5% and better uniformity of exit port radiance and spectral irradiance created by an integrating sphere. Uniformity in broad spectrum and spectral bands are explored. We discuss mapping techniques and results as a function of observed uniformity as well as laboratory testing results customized to match with customer's instrumentation field of view. We will also discuss recommendations with basic commercial instrumentation, we have used to validate, inspect, and improve correlation of uniformity measurements with the intended application.

  10. Uniform deposition of size-selected clusters using Lissajous scanning

    SciTech Connect

    Beniya, Atsushi; Watanabe, Yoshihide; Hirata, Hirohito

    2016-05-15

    Size-selected clusters can be deposited on the surface using size-selected cluster ion beams. However, because of the cross-sectional intensity distribution of the ion beam, it is difficult to define the coverage of the deposited clusters. The aggregation probability of the cluster depends on coverage, whereas cluster size on the surface depends on the position, despite the size-selected clusters are deposited. It is crucial, therefore, to deposit clusters uniformly on the surface. In this study, size-selected clusters were deposited uniformly on surfaces by scanning the cluster ions in the form of Lissajous pattern. Two sets of deflector electrodes set in orthogonal directions were placed in front of the sample surface. Triangular waves were applied to the electrodes with an irrational frequency ratio to ensure that the ion trajectory filled the sample surface. The advantages of this method are simplicity and low cost of setup compared with raster scanning method. The authors further investigated CO adsorption on size-selected Pt{sub n} (n = 7, 15, 20) clusters uniformly deposited on the Al{sub 2}O{sub 3}/NiAl(110) surface and demonstrated the importance of uniform deposition.

  11. Christiansen Revisited: Rethinking Quantification of Uniformity in Rainfall Simulator Studies

    NASA Astrophysics Data System (ADS)

    Green, Daniel; Pattison, Ian

    2016-04-01

    Rainfall simulators, whether based within a laboratory or field setting are used extensively within a number of fields of research, including plot-scale runoff, infiltration and erosion studies, irrigation and crop management and scaled investigations into urban flooding. Rainfall simulators offer a number of benefits, including the ability to create regulated and repeatable rainfall characteristics (e.g. intensity, duration, drop size distribution and kinetic energy) without relying on unpredictable natural precipitation regimes. Ensuring and quantifying spatially uniform simulated rainfall across the entirety of the plot area is of particular importance to researchers undertaking rainfall simulation. As a result, numerous studies have focused on the quantification and improvement of uniformity values. Several statistical methods for the assessment of rainfall simulator uniformity have been developed. However, the Christiansen Uniformity Coefficient (CUC) suggested by Christiansen (1942) is most frequently used. Despite this, there is no set methodology and researchers can adapt or alter factors such as the quantity, as well as the spacing, distance and location of the measuring beakers used to derive CUC values. Because CUC values are highly sensitive to the resolution of the data, i.e. the number of observations taken, many densely distributed measuring containers subjected to the same experimental conditions may generate a significantly lower CUC value than fewer, more sparsely distributed measuring containers. Thus, the simulated rainfall under a higher resolution sampling method could appear less uniform than when using a coarser resolution sampling method, despite being derived from the same initial rainfall conditions. Expressing entire plot uniformity as a single, simplified percentage value disregards valuable qualitative information about plot uniformity, such as the small-scale spatial distribution of rainfall over the plot surface and whether these

  12. 25 CFR 700.103 - Uniform Act.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 2 2011-04-01 2011-04-01 false Uniform Act. 700.103 Section 700.103 Indians THE OFFICE... and Instructions Definitions § 700.103 Uniform Act. The term Uniform Act means the Uniform Relocation Assistance and Real Property Acquisition Policies Act of 1970 (84 Stat. 1894; 42 U.S.C. 4601 et seq.; Pub. L...

  13. 25 CFR 700.103 - Uniform Act.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 2 2010-04-01 2010-04-01 false Uniform Act. 700.103 Section 700.103 Indians THE OFFICE... and Instructions Definitions § 700.103 Uniform Act. The term Uniform Act means the Uniform Relocation Assistance and Real Property Acquisition Policies Act of 1970 (84 Stat. 1894; 42 U.S.C. 4601 et seq.; Pub. L...

  14. 25 CFR 700.103 - Uniform Act.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 2 2012-04-01 2012-04-01 false Uniform Act. 700.103 Section 700.103 Indians THE OFFICE... and Instructions Definitions § 700.103 Uniform Act. The term Uniform Act means the Uniform Relocation Assistance and Real Property Acquisition Policies Act of 1970 (84 Stat. 1894; 42 U.S.C. 4601 et seq.; Pub. L...

  15. 25 CFR 700.103 - Uniform Act.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 2 2013-04-01 2013-04-01 false Uniform Act. 700.103 Section 700.103 Indians THE OFFICE... and Instructions Definitions § 700.103 Uniform Act. The term Uniform Act means the Uniform Relocation Assistance and Real Property Acquisition Policies Act of 1970 (84 Stat. 1894; 42 U.S.C. 4601 et seq.; Pub. L...

  16. Small Arms: Treated Uniforms for Personal Protection

    USDA-ARS?s Scientific Manuscript database

    Permethrin-treatment of field-worn U.S. Military uniforms has been standard practice since 1991. The uniform fabric composition has changed significantly from 100% cotton to 50:50 nylon:cotton Battle Dress Uniforms (BDUs), to 50:50 nylon:cotton Army Combat Uniforms (ACUs) with wrinkle-free finish, a...

  17. 46 CFR 310.11 - Cadet uniforms.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... for State, Territorial or Regional Maritime Academies and Colleges § 310.11 Cadet uniforms. Cadet uniforms shall be supplied at the school in accordance with the uniform regulations of the School. Those... 46 Shipping 8 2011-10-01 2011-10-01 false Cadet uniforms. 310.11 Section 310.11 Shipping...

  18. 46 CFR 310.11 - Cadet uniforms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... for State, Territorial or Regional Maritime Academies and Colleges § 310.11 Cadet uniforms. Cadet uniforms shall be supplied at the school in accordance with the uniform regulations of the School. Those... 46 Shipping 8 2013-10-01 2013-10-01 false Cadet uniforms. 310.11 Section 310.11 Shipping...

  19. 46 CFR 310.11 - Cadet uniforms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... for State, Territorial or Regional Maritime Academies and Colleges § 310.11 Cadet uniforms. Cadet uniforms shall be supplied at the school in accordance with the uniform regulations of the School. Those... 46 Shipping 8 2014-10-01 2014-10-01 false Cadet uniforms. 310.11 Section 310.11 Shipping...

  20. 46 CFR 310.11 - Cadet uniforms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... for State, Territorial or Regional Maritime Academies and Colleges § 310.11 Cadet uniforms. Cadet uniforms shall be supplied at the school in accordance with the uniform regulations of the School. Those... 46 Shipping 8 2012-10-01 2012-10-01 false Cadet uniforms. 310.11 Section 310.11 Shipping...

  1. Reactor for making uniform capsules

    NASA Technical Reports Server (NTRS)

    Wang, Taylor G. (Inventor); Anikumar, Amrutur V. (Inventor); Lacik, Igor (Inventor)

    1999-01-01

    The present invention provides a novel reactor for making capsules with uniform membrane. The reactor includes a source for providing a continuous flow of a first liquid through the reactor; a source for delivering a steady stream of drops of a second liquid to the entrance of the reactor; a main tube portion having at least one loop, and an exit opening, where the exit opening is at a height substantially equal to the entrance. In addition, a method for using the novel reactor is provided. This method involves providing a continuous stream of a first liquid; introducing uniformly-sized drops of the second liquid into the stream of the first liquid; allowing the drops to react in the stream for a pre-determined period of time; and collecting the capsules.

  2. Method for uniformly bending conduits

    DOEpatents

    Dekanich, S.J.

    1984-04-27

    The present invention is directed to a method for bending metal tubing through various radii while maintaining uniform cross section of the tubing. The present invention is practical by filling the tubing to a sufficient level with water, freezing the water to ice and bending the ice-filled tubing in a cooled die to the desired radius. The use of the ice as a filler material provides uniform cross-sectional bends of the tubing and upon removal of the ice provides an uncontaminated interior of the tubing which will enable it to be used in its intended application without encountering residual contaminants in the tubing due to the presence of the filler material.

  3. Vertical uniformity of cells and nuclei in epithelial monolayers.

    PubMed

    Neelam, Srujana; Hayes, Peter Robert; Zhang, Qiao; Dickinson, Richard B; Lele, Tanmay P

    2016-01-22

    Morphological variability in cytoskeletal organization, organelle position and cell boundaries is a common feature of cultured cells. Remarkable uniformity and reproducibility in structure can be accomplished by providing cells with defined geometric cues. Cells in tissues can also self-organize in the absence of directing extracellular cues; however the mechanical principles for such self-organization are not understood. We report that unlike horizontal shapes, the vertical shapes of the cell and nucleus in the z-dimension are uniform in cells in cultured monolayers compared to isolated cells. Apical surfaces of cells and their nuclei in monolayers were flat and heights were uniform. In contrast, isolated cells, or cells with disrupted cell-cell adhesions had nuclei with curved apical surfaces and variable heights. Isolated cells cultured within micron-sized square wells displayed flat cell and nuclear shapes similar to cells in monolayers. Local disruption of nuclear-cytoskeletal linkages resulted in spatial variation in vertical uniformity. These results suggest that competition between cell-cell pulling forces that expand and shorten the vertical cell cross-section, thereby widening and flattening the nucleus, and the resistance of the nucleus to further flattening results in uniform cell and nuclear cross-sections. Our results reveal the mechanical principles of self-organized vertical uniformity in cell monolayers.

  4. Vertical uniformity of cells and nuclei in epithelial monolayers

    PubMed Central

    Neelam, Srujana; Hayes, Peter Robert; Zhang, Qiao; Dickinson, Richard B.; Lele, Tanmay P.

    2016-01-01

    Morphological variability in cytoskeletal organization, organelle position and cell boundaries is a common feature of cultured cells. Remarkable uniformity and reproducibility in structure can be accomplished by providing cells with defined geometric cues. Cells in tissues can also self-organize in the absence of directing extracellular cues; however the mechanical principles for such self-organization are not understood. We report that unlike horizontal shapes, the vertical shapes of the cell and nucleus in the z-dimension are uniform in cells in cultured monolayers compared to isolated cells. Apical surfaces of cells and their nuclei in monolayers were flat and heights were uniform. In contrast, isolated cells, or cells with disrupted cell-cell adhesions had nuclei with curved apical surfaces and variable heights. Isolated cells cultured within micron-sized square wells displayed flat cell and nuclear shapes similar to cells in monolayers. Local disruption of nuclear-cytoskeletal linkages resulted in spatial variation in vertical uniformity. These results suggest that competition between cell-cell pulling forces that expand and shorten the vertical cell cross-section, thereby widening and flattening the nucleus, and the resistance of the nucleus to further flattening results in uniform cell and nuclear cross-sections. Our results reveal the mechanical principles of self-organized vertical uniformity in cell monolayers. PMID:26795751

  5. Uniform-droplet spray forming

    SciTech Connect

    Blue, C.A.; Sikka, V.K.; Chun, Jung-Hoon; Ando, T.

    1997-04-01

    The uniform-droplet process is a new method of liquid-metal atomization that results in single droplets that can be used to produce mono-size powders or sprayed-on to substrates to produce near-net shapes with tailored microstructure. The mono-sized powder-production capability of the uniform-droplet process also has the potential of permitting engineered powder blends to produce components of controlled porosity. Metal and alloy powders are commercially produced by at least three different methods: gas atomization, water atomization, and rotating disk. All three methods produce powders of a broad range in size with a very small yield of fine powders with single-sized droplets that can be used to produce mono-size powders or sprayed-on substrates to produce near-net shapes with tailored microstructures. The economical analysis has shown the process to have the potential of reducing capital cost by 50% and operating cost by 37.5% when applied to powder making. For the spray-forming process, a 25% savings is expected in both the capital and operating costs. The project is jointly carried out at Massachusetts Institute of Technology (MIT), Tuffs University, and Oak Ridge National Laboratory (ORNL). Preliminary interactions with both finished parts and powder producers have shown a strong interest in the uniform-droplet process. Systematic studies are being conducted to optimize the process parameters, understand the solidification of droplets and spray deposits, and develop a uniform-droplet-system (UDS) apparatus appropriate for processing engineering alloys.

  6. Uniform-Dead-Weight Brazing

    NASA Technical Reports Server (NTRS)

    Gaw, William D.

    1991-01-01

    Method of deadweight loading for vacuum-furnace brazing improves quality of joint, increases yield, and reduces costs. In improved method, plates weighted with heavy stainless-steel blocks. Blocks act independently and are immune to distortion. Besides being uniformly distributed, force applied to plates larger and repeatable from one brazing operation to next. Larger blocks used on edges of plates, where more thermal mass needed to reduce differences between temperatures of interior and edge as temperature of furnace varied.

  7. Uniform batch processing using microwaves

    NASA Technical Reports Server (NTRS)

    Barmatz, Martin B. (Inventor); Jackson, Henry W. (Inventor)

    2000-01-01

    A microwave oven and microwave heating method generates microwaves within a cavity in a predetermined mode such that there is a known region of uniform microwave field. Samples placed in the region will then be heated in a relatively identical manner. Where perturbations induced by the samples are significant, samples are arranged in a symmetrical distribution so that the cumulative perturbation at each sample location is the same.

  8. Note: 3D printed spheroid for uniform magnetic field generation

    NASA Astrophysics Data System (ADS)

    Öztürk, Y.; Aktaş, B.

    2016-10-01

    This article is focused on a novel and practical production method for a uniform magnetic field generator. The method involves building of a surface coil template using a desktop 3D printer and winding of a conducting wire onto the structure using surface grooves as a guide. Groove pattern was based on the parametric spheroidal helical coil formula. The coil was driven by a current source and the magnetic field inside was measured using a Hall probe placed into the holes on the printed structure. The measurements are found to be in good agreement with our finite element analysis results and indicate a fairly uniform field inside.

  9. Non-uniform exponential tension splines

    NASA Astrophysics Data System (ADS)

    Bosner, Tina; Rogina, Mladen

    2007-11-01

    We describe explicitly each stage of a numerically stable algorithm for calculating with exponential tension B-splines with non-uniform choice of tension parameters. These splines are piecewisely in the kernel of D 2(D 2?p 2), where D stands for ordinary derivative, defined on arbitrary meshes, with a different choice of the tension parameter p on each interval. The algorithm provides values of the associated B-splines and their generalized and ordinary derivatives by performing positive linear combinations of positive quantities, described as lower-order exponential tension splines. We show that nothing else but the knot insertion algorithm and good approximation of a few elementary functions is needed to achieve machine accuracy. The underlying theory is that of splines based on Chebyshev canonical systems which are not smooth enough to be ECC-systems. First, by de Boor algorithm we construct exponential tension spline of class C 1, and then we use quasi-Oslo type algorithms to evaluate classical non-uniform C 2 tension exponential splines.

  10. Two inhomogeneities of irregular shape with internal uniform stress fields interacting with a screw dislocation

    NASA Astrophysics Data System (ADS)

    Wang, Xu; Schiavone, Peter

    2016-07-01

    Using complex variable methods and conformal mapping techniques, we demonstrate rigorously that two inhomogeneities of irregular shape interacting with a screw dislocation can indeed maintain uniform internal stress distributions. Our analysis indicates that while the internal uniform stresses are independent of the existence of the screw dislocation, the shapes of the two inhomogeneities required to achieve this uniformity depend on the Burgers vector, the location of the screw dislocation, and the size of the inhomogeneities. In addition, we find that this uniformity of the internal stress field is achievable also when the two inhomogeneities interact with an arbitrary number of discrete screw dislocations in the matrix.

  11. Local self-uniformity in photonic networks

    NASA Astrophysics Data System (ADS)

    Sellers, Steven R.; Man, Weining; Sahba, Shervin; Florescu, Marian

    2017-02-01

    The interaction of a material with light is intimately related to its wavelength-scale structure. Simple connections between structure and optical response empower us with essential intuition to engineer complex optical functionalities. Here we develop local self-uniformity (LSU) as a measure of a random network's internal structural similarity, ranking networks on a continuous scale from crystalline, through glassy intermediate states, to chaotic configurations. We demonstrate that complete photonic bandgap structures possess substantial LSU and validate LSU's importance in gap formation through design of amorphous gyroid structures. Amorphous gyroid samples are fabricated via three-dimensional ceramic printing and the bandgaps experimentally verified. We explore also the wing-scale structuring in the butterfly Pseudolycaena marsyas and show that it possesses substantial amorphous gyroid character, demonstrating the subtle order achieved by evolutionary optimization and the possibility of an amorphous gyroid's self-assembly.

  12. Local self-uniformity in photonic networks

    PubMed Central

    Sellers, Steven R.; Man, Weining; Sahba, Shervin; Florescu, Marian

    2017-01-01

    The interaction of a material with light is intimately related to its wavelength-scale structure. Simple connections between structure and optical response empower us with essential intuition to engineer complex optical functionalities. Here we develop local self-uniformity (LSU) as a measure of a random network's internal structural similarity, ranking networks on a continuous scale from crystalline, through glassy intermediate states, to chaotic configurations. We demonstrate that complete photonic bandgap structures possess substantial LSU and validate LSU's importance in gap formation through design of amorphous gyroid structures. Amorphous gyroid samples are fabricated via three-dimensional ceramic printing and the bandgaps experimentally verified. We explore also the wing-scale structuring in the butterfly Pseudolycaena marsyas and show that it possesses substantial amorphous gyroid character, demonstrating the subtle order achieved by evolutionary optimization and the possibility of an amorphous gyroid's self-assembly. PMID:28211466

  13. Local self-uniformity in photonic networks.

    PubMed

    Sellers, Steven R; Man, Weining; Sahba, Shervin; Florescu, Marian

    2017-02-17

    The interaction of a material with light is intimately related to its wavelength-scale structure. Simple connections between structure and optical response empower us with essential intuition to engineer complex optical functionalities. Here we develop local self-uniformity (LSU) as a measure of a random network's internal structural similarity, ranking networks on a continuous scale from crystalline, through glassy intermediate states, to chaotic configurations. We demonstrate that complete photonic bandgap structures possess substantial LSU and validate LSU's importance in gap formation through design of amorphous gyroid structures. Amorphous gyroid samples are fabricated via three-dimensional ceramic printing and the bandgaps experimentally verified. We explore also the wing-scale structuring in the butterfly Pseudolycaena marsyas and show that it possesses substantial amorphous gyroid character, demonstrating the subtle order achieved by evolutionary optimization and the possibility of an amorphous gyroid's self-assembly.

  14. Image Correlation Microscopy for Uniform Illumination

    PubMed Central

    Gaborski, Thomas R.; Sealander, Michael N.; Ehrenberg, Morton; Waugh, Richard E.; McGrath, James L.

    2011-01-01

    Image cross-correlation microscopy (ICM) is a technique that quantifies the motion of fluorescent features in an image by measuring the temporal autocorrelation function decay in a time-lapse image sequence. ICM has traditionally employed laser-scanning microscopes because the technique emerged as an extension of laser-based fluorescence correlation spectroscopy (FCS). In this work, we show that image correlation can also be used to measure fluorescence dynamics in uniform illumination or wide-field imaging systems and we call our new approach uniform illumination image correlation microscopy (UI-ICM). Wide-field microscopy is not only a simpler, less expensive imaging modality, but it offers the capability of greater temporal resolution over laser-scanning systems. In traditional laser-scanning ICM, lateral mobility is calculated from the temporal de-correlation of an image, where the characteristic length is the illuminating laser beam width. In wide-field microscopy, the diffusion length is defined by the feature size using the spatial autocorrelation function (SACF). Correlation function decay in time occurs as an object diffuses from its original position. We show that theoretical and simulated comparisons between Gaussian and uniform features indicate the temporal autocorrelation function (TACF) depends strongly on particle size and not particle shape. In this report, we establish the relationships between the SACF feature size, TACF characteristic time and the diffusion coefficient for UI-ICM using analytical, Monte-Carlo and experimental validation with particle tracking algorithms. Additionally, we demonstrate UI-ICM analysis of adhesion molecule domain aggregation and diffusion on the surface of human neutrophils. PMID:20055917

  15. Uniform Microparticles with Controllable Highly Interconnected Hierarchical Porous Structures.

    PubMed

    Zhang, Mao-Jie; Wang, Wei; Yang, Xiu-Lan; Ma, Bing; Liu, Ying-Mei; Xie, Rui; Ju, Xiao-Jie; Liu, Zhuang; Chu, Liang-Yin

    2015-07-01

    A simple and versatile strategy is developed for one-step fabrication of uniform polymeric microparticles with controllable highly interconnected hierarchical porous structures. Monodisperse water-in-oil-in-water (W/O/W) emulsions, with methyl methacrylate, ethylene glycol dimethacrylate, and glycidyl methacrylate as the monomer-containing oil phase, are generated from microfluidics and used for constructing the microparticles. Due to the partially miscible property of oil/aqueous phases, the monodisperse W/O/W emulsions can deform into desired shapes depending on the packing structure of inner aqueous microdrops, and form aqueous nanodrops in the oil phase. The deformed W/O/W emulsions allow template syntheses of highly interconnected hierarchical porous microparticles with precisely and individually controlled pore size, porosity, functionality, and particle shape. The microparticles elaborately combine the advantages of enhanced mass transfer, large functional surface area, and flexibly tunable functionalities, providing an efficient strategy to physically and chemically achieve enhanced synergetic performances for extensive applications. This is demonstrated by using the microparticles for oil removal for water purification and protein adsorption for bioseparation. The method proposed in this study provides full versatility for fabrication of functional polymeric microparticles with controllable hierarchical porous structures for enhancing and even broadening their applications.

  16. Novel non-imaging optic design for uniform illumination

    NASA Astrophysics Data System (ADS)

    Babadi, S.; Ramirez-Iniguez, R.; Boutaleb, T.; Mallick, T.

    2016-03-01

    The Dielectric Totally Internally Reflecting Concentrator (DTIRC) has been developed in the past for wireless infrared communications and solar energy applications. This paper proposes a novel non-imaging optic design based on the DTIRC family of concentrators for use in illumination applications. The novel optic can be integrated with a light emitting diode (LED) and can be tailored to meet specific requirements. The proposed optic can be used as a first or secondary optic to provide uniform illumination within a circular footprint with a desired radius. The results from this work show that, with the optimised DTIRC, it is possible to achieve a uniformity of illuminance of over 95%.

  17. Willow: a uniform search interface.

    PubMed Central

    Ketchell, D S; Freedman, M M; Jordan, W E; Lightfoot, E M; Heyano, S; Libbey, P A

    1996-01-01

    The objective of the Willow Project is to develop a uniform search interface that allows a diverse community of users to retrieve information from heterogeneous network-based information resources. Willow separates the user interface from the database management or information retrieval system. It provides a graphic user interface to a variety of information resources residing on diverse hosts, and using different search engines and idiomatic query languages through networked-based client-server and Transmission Control Protocol/Internet Protocol (TCP/IP) protocols. It is based on a "database driver'' model, which allows new database hosts to be added without altering Willow itself. Willow employs a multimedia extension mechanism to launch external viewers to handle data in almost any form. Drivers are currently available for a local BRS/SEARCH system and the Z39.50 protocol. Students, faculty, clinicians, and researchers at the University of Washington are currently offered 30 local and remote databases via Willow. They conduct more than 250,000 sessions a month in libraries, medical centers and clinics, laboratories, and offices, and from home. The Massachusetts Institute of Technology is implementing Willow as its uniform search interface to Z39.50 hosts. PMID:8750388

  18. Achieving a slippery, liquid-infused porous surface with anti-icing properties by direct deposition of flame synthesized aerosol nanoparticles on a thermally fragile substrate

    NASA Astrophysics Data System (ADS)

    Juuti, Paxton; Haapanen, Janne; Stenroos, Christian; Niemelä-Anttonen, Henna; Harra, Juha; Koivuluoto, Heli; Teisala, Hannu; Lahti, Johanna; Tuominen, Mikko; Kuusipalo, Jurkka; Vuoristo, Petri; Mäkelä, Jyrki M.

    2017-04-01

    Slippery, liquid-infused porous surfaces offer a promising route for producing omniphobic and anti-icing surfaces. Typically, these surfaces are made as a coating with expensive and time consuming assembly methods or with fluorinated films and oils. We report on a route for producing liquid-infused surfaces, which utilizes a liquid precursor fed oxygen-hydrogen flame to produce titania nanoparticles deposited directly on a low-density polyethylene film. This porous nanocoating, with thickness of several hundreds of nanometers, is then filled with silicone oil. The produced surfaces are shown to exhibit excellent anti-icing properties, with an ice adhesion strength of ˜12 kPa, which is an order of magnitude improvement when compared to the plain polyethylene film. The surface was also capable of maintaining this property even after cyclic icing testing.

  19. Achieving excellence.

    PubMed

    Williams, R B

    1986-03-01

    The concept of achieving excellence in pharmacy through development of effective leadership is discussed. The majority of hospital pharmacy directors have had very little education and training in management and effective leadership. Yet, excellent leadership skills will be needed to transform pharmacy more completely into a health profession. The management style most likely to be effective in this era of change is one that encompasses a high regard for both people and production through shared responsibility, high participation, involvement, and commitment. The following recommendations are offered to help achieve excellence through effective leadership: the ethic of self-development must be instilled in aspiring managers; courses in human behavior, leadership, and management should be added to undergraduate pharmacy curricula; pharmacy technicians should be educated in college-based programs that focus on drug distribution; Master of Science programs in hospital pharmacy should be deleted or restructured to focus on leadership and management; regional "centers for excellence" in leadership education should be developed; general residency training should be incorporated in undergraduate education so that more advanced residencies can be offered to graduates; high-level, self-study programs in management and leadership need to be developed, and substantial research funds need to be dedicated to the study of hospital pharmacy management.

  20. Investigation of light output uniformity and performance using a UV transmitting glass optic for a multi-UV LED array

    NASA Astrophysics Data System (ADS)

    Jasenak, Brian; Willsey, Rachel; Willsey, Adam; Forish, James

    2016-03-01

    Ultraviolet light-emitting diode (UV LED) adoption is accelerating; they are being used in new applications such as UV curing, germicidal irradiation, nondestructive testing, and forensic analysis. In many of these applications, it is critically important to produce a uniform light distribution and consistent surface irradiance. Flat panes of fused quartz, silica, or glass are commonly used to cover and protect multi-UV LED arrays. However, they don't offer the advantages of an optical lens design. An investigation was conducted to determine the effect of a secondary glass optic on the uniformity of the light distribution and irradiance. Glass optics capable of transmitting UV-A, UV-B, and UV-C wavelengths can improve light distribution and intensity. In this study, a UV transmitting glass formulation and secondary linear optic were designed and manufactured to demonstrate their effects on achievable irradiance intensity and uniformity. Prismatic patterning on the light source surface of the lens was used to minimize reflection losses on the incident surface of the glass. Fresnel optics were molded into the opposite side of the UV transmitting glass to control the refraction of the light and to gain the desired light intensity distribution from two multi-UV LED arrays. A 20% increase in relative irradiance was observed while maintaining the same coverage area. This work discusses the optical design and the resulting benefits of controlled light output on UV LED systems, which include reduced driving current, decreased thermal deterioration, improved energy efficiency, and longer LED lifetime.

  1. Irradiation of poly(tetrafluoroethylene) surfaces by CF4 plasma to achieve robust superhydrophobic and enhanced oleophilic properties for biological applications.

    PubMed

    Salapare, Hernando S; Suarez, Beverly Anne T; Cosiñero, Hannah Shamina O; Bacaoco, Miguel Y; Ramos, Henry J

    2015-01-01

    Poly(tetrafluoroethylene) (PTFE) was irradiated by CF4 plasma produced in the gas discharge ion source facility to produce stable and robust superhydrophobic surfaces and to enhance the materials' oleophilic property for biological applications. The characterizations employed on the samples are contact angle measurements, analysis of the surface morphology (scanning electron microscopy), surface roughness measurements (atomic force microscopy) and analysis of the surface chemistry (Fourier transform infrared spectroscopy). Superhydrophobic behavior with water contact angles as high as 156° was observed. The wettability of all the treated samples was found to be stable in time as evidenced by the statistically insignificant differences in the hysteresis contact angles. The level of enhanced hydrophobicity depended on the plasma energies (i.e. irradiation times, discharge current, and discharge voltage); higher plasma energies produced surfaces with high hydrophobicity. The plasma treatment also enhanced the oleophilic property of the materials' surface as evidenced by the decrease in the PDMS-oil contact angle from 33° to as low as 10°. The superhydrophobicity of the modified PTFE and the enhancement of its oleophilic property were due to (1) the changes in the roughness of the surface, (2) the formation of nanoparticles or nanostructures on the surface, and (3) the changes in the surface chemistry.

  2. Enhanced Biosensor Platforms for Detecting the Atherosclerotic Biomarker VCAM1 Based on Bioconjugation with Uniformly Oriented VCAM1-Targeting Nanobodies

    PubMed Central

    Ta, Duy Tien; Guedens, Wanda; Vranken, Tom; Vanschoenbeek, Katrijn; Steen Redeker, Erik; Michiels, Luc; Adriaensens, Peter

    2016-01-01

    Surface bioconjugation of biomolecules has gained enormous attention for developing advanced biomaterials including biosensors. While conventional immobilization (by physisorption or covalent couplings using the functional groups of the endogenous amino acids) usually results in surfaces with low activity, reproducibility and reusability, the application of methods that allow for a covalent and uniformly oriented coupling can circumvent these limitations. In this study, the nanobody targeting Vascular Cell Adhesion Molecule-1 (NbVCAM1), an atherosclerotic biomarker, is engineered with a C-terminal alkyne function via Expressed Protein Ligation (EPL). Conjugation of this nanobody to azidified silicon wafers and Biacore™ C1 sensor chips is achieved via Copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) “click” chemistry to detect VCAM1 binding via ellipsometry and surface plasmon resonance (SPR), respectively. The resulting surfaces, covered with uniformly oriented nanobodies, clearly show an increased antigen binding affinity, sensitivity, detection limit, quantitation limit and reusability as compared to surfaces prepared by random conjugation. These findings demonstrate the added value of a combined EPL and CuAAC approach as it results in strong control over the surface orientation of the nanobodies and an improved detecting power of their targets—a must for the development of advanced miniaturized, multi-biomarker biosensor platforms. PMID:27399790

  3. Process Sprays Uniforms Plasma Coatings

    NASA Technical Reports Server (NTRS)

    Sliney, H. E.; Jacobson, T. P.; Walther, G. C.; Nakamura, H. H.

    1983-01-01

    Composite-powder processing procedure developed along with plasma-spray parameters to achieve homogeneous, well-bonded, low-porosity, self-lubricating coatings. Multicomponent plasma coatings are applied without segretation of components.

  4. 78 FR 50359 - Civilian Health and Medical Program of the Uniformed Services (CHAMPUS); TRICARE Uniform Health...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-19

    ... Services (CHAMPUS); TRICARE Uniform Health Maintenance Organization (HMO) Benefit--Prime Enrollment Fee... Uniform Health Maintenance Organization (HMO) Benefit--Prime Enrollment Fee Exemption for Survivors of...

  5. A Single Step Lapping and Polishing Process for Achieving Surfaces of Compound Semiconductors with Atomic Flatness using a Sub-micron Agglomerate-free Alumina Slurry

    SciTech Connect

    P.S. Dutta; G. Rajagopalan; J.J. Gutmann; D. Keller; L. Sweet

    2002-08-29

    A novel approach for a single step lapping and final polishing of III-V and II-VI compounds using agglomerate-free alumina slurries has been developed. The agglomerate-free nature of the sub-micron slurry leads to removal rates comparable to conventional slurries (with larger particles of tens of microns) used for semiconductor lapping. Surfaces with minimal surface damage and extremely low surface roughness have been obtained using the sub-micron slurries and a soft pad. Strategies for post polishing surface cleaning have been discussed. The new methodology has been experimented on GaSb, InAs, GaAs, InP, InSb, CdTe, GaInSb, GaInAs, AlGaAsSb, GaInAsSb and HgCdTe. Selected results of surface analyses of GaSb and GaInSb using atomic force microscopy will be presented.

  6. Attitudes of Parents about School Uniforms.

    ERIC Educational Resources Information Center

    West, Charles K.; Tidwell, Diane K.; Bomba, Anne K.; Elmore, Patsy Alexander

    1999-01-01

    Responses from 144 parents of fourth graders showed that 56% favored uniforms in public schools; most agreed that uniforms contributed to a conducive learning environment, promoted school spirit, and discouraged violence; and most disagreed that uniforms cost more than other types of clothing. (SK)

  7. Design Techniques for Uniform-DFT, Linear Phase Filter Banks

    NASA Technical Reports Server (NTRS)

    Sun, Honglin; DeLeon, Phillip

    1999-01-01

    Uniform-DFT filter banks are an important class of filter banks and their theory is well known. One notable characteristic is their very efficient implementation when using polyphase filters and the FFT. Separately, linear phase filter banks, i.e. filter banks in which the analysis filters have a linear phase are also an important class of filter banks and desired in many applications. Unfortunately, it has been proved that one cannot design critically-sampled, uniform-DFT, linear phase filter banks and achieve perfect reconstruction. In this paper, we present a least-squares solution to this problem and in addition prove that oversampled, uniform-DFT, linear phase filter banks (which are also useful in many applications) can be constructed for perfect reconstruction. Design examples are included illustrate the methods.

  8. Uniformly Rotating Single Substance Bodies

    NASA Astrophysics Data System (ADS)

    Leonard, Charles Michael Leo

    This dissertation explicitly and in detail solves the extended rotator problem in the uncharged relativistic classical cases of most physical interest. It shows that no plausible relativistic solutions exist in the literature of the extended rotator and that the point rotator solutions sometimes ballyhooed are not to be taken seriously. Explicit energy speedratio functions, angular momentum speedratio functions, Hamiltonian, Lagrangian, and other important characteristic functions of the state of uniform rotation of the extended body are detailed. This dissertation does not retreat to an 'analysis' of just the point rotator --which so many others have done and done incorrectly, or at best misleadingly, by hiding implausible assumptions in manifestly covariant formats. Assumptions in the model are not hidden but are brought out and analyzed as to their relevance for highlighting the core of the uniform rotation physics. Neither does the author hide any ignorance of the internal holding field for the rotator. Formulae for the characteristic Minimum Holding Field are explicitly given and their relativistic relevance is shown. The demonstration that such fields can be ignored in the energy and angular momentum expressions is completely detailed. The explicit Stress-Energy Tensor for the entire closed rotator system is given with all that entails as to the inescapability of the results from out of that mathematics. The generality of the finiteness of the extreme relativistic rotational limit is detailed and explained with its stark essential contrast to the infinite limit in the case of extreme relativistic translation of a body. The rotator is shown to possess a rich mathematical structure. Many elegant interconnection formulae are found as well as new Hamiltonian formulae --sometimes of considerable complexity. Exact rotator formulae as well as graphs, tables, and even interesting approximations are provided. New nonlinear differential equations are discovered and

  9. Formation of ultrafine uniform gold nanoparticles by sputtering and redeposition

    SciTech Connect

    Zhou Xiuli; Wei Qiangmin; Sun Kai; Wang Lumin

    2009-03-30

    Uniformly distributed Au nanoparticles with controllable size were fabricated by focused ion beam bombardment of thin gold films. In situ scanning electron microscopy and ex situ transmission electron microscopy were used to characterize the nanoparticles. Results show that a dual particle size distribution was generated at low ion fluence, while highly uniform Au particles with diameters around 2 nm formed at high fluence. The balance between sputtering and redeposition is responsible for the formation and size control of the nanoparticles. Optical absorption measurement revealed strong size dependant resonances that are attributed to the surface plasmon resonance of the Au particles.

  10. Natural frequency of uniform and optimized tetrahedral truss platforms

    NASA Technical Reports Server (NTRS)

    Wu, K. Chauncey; Lake, Mark S.

    1994-01-01

    Qualitative and quantitative estimates for the fundamental frequency of uniform and optimized tetrahedral truss platforms are determined. A semiempirical equation is developed for the frequency of free-free uniform trusses as a function of member material properties, truss dimensions, and parasitic (nonstructural) mass fraction Mp/Mt. Optimized trusses with frequencies approximately two times those of uniform trusses are determined by varying the cross-sectional areas of member groups. Trusses with 3 to 8 rings, no parasitic mass, and member areas up to 25 times the minimum area are optimized. Frequencies computed for ranges of both Mp/Mt and the ratio of maximum area to minimum area are normalized to the frequency of a uniform truss with no parasitic mass. The normalized frequency increases with the number of rings, and both frequency and the ratio of maximum area to minimum area decrease with increasing Mp/Mt. Frequency improvements that are achievable with a limited number of member areas are estimated for a 3-ring truss by using Taguchi methods. Joint stiffness knockdown effects are also considered. Comparison of optimized and baseline uniform truss frequencies indicates that tailoring can significantly increase structural frequency; maximum gains occur for trusses with low values of Mp/Mt. This study examines frequency trends for ranges of structural parameters and may be used as a preliminary design guide.

  11. Improvement of uniformity in a weakly magnetized inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Lee, W. H.; Cheong, H. W.; Kim, J. W.; Whang, K. W.

    2015-12-01

    Magnetic fields are applied to inductively coupled plasma (ICP) to achieve high plasma densities using electromagnets. If the magnetic fields are set up such that the magnitude of magnetic flux density on the substrate decreases with both radial and axial distances from the substrate’s center (here after referred to as M-ICP-A), the plasma density increases by 237% compared with that for ICP although the non-uniformity of the plasma density for M-ICP-A (11.1%) is higher than that for ICP (10.9%). As the rate of decrease in the magnitude of magnetic flux density on the substrate increases both radially and axially, the non-uniformity in the plasma density increases further. The increase in the non-uniformity for M-ICP-A was confirmed to arise from the flute instability. To suppress the flute instability, we arranged the magnitude of magnetic flux density on the substrate to increase with increasing distance from the substrate center both radially and axially (here after referred to as M-ICP-V). In this configuration, plasma fluctuations were not observed, hence the plasma density non-uniformity was lowered to 8.1%, although the measured plasma density was higher than that for M-ICP-A. The oxide etch-rate non-uniformity in M-ICP-V (2.5%) was also lower than that for ICP (5.2%) or that for M-ICP-A (21.4%).

  12. Individualized volume CT dose index determined by cross-sectional area and mean density of the body to achieve uniform image noise of contrast-enhanced pediatric chest CT obtained at variable kV levels and with combined tube current modulation.

    PubMed

    Goo, Hyun Woo

    2011-07-01

    A practical body-size adaptive protocol providing uniform image noise at various kV levels is not available for pediatric CT. To develop a practical contrast-enhanced pediatric chest CT protocol providing uniform image noise by using an individualized volume CT dose index (CTDIvol) determined by the cross-sectional area and density of the body at variable kV levels and with combined tube current modulation. A total of 137 patients (mean age, 7.6 years) underwent contrast-enhanced pediatric chest CT based on body weight. From the CTDIvol, image noise, and area and mean density of the cross-section at the lung base in the weight-based group, the best fit equation was estimated with a very high correlation coefficient (γ(2) = 0.86, P < 0.001). For the next study, 177 patients (mean age, 7.9 years; the CTDIvol group) underwent contrast-enhanced pediatric chest CT with the CTDIvol determined individually by the best fit equation. CTDIvol values on the dose report after CT scanning, noise differences from the target noise, areas, and mean densities were compared between these two groups. The CTDIvol values (mean ± standard deviation, 1.6 ± 0.7 mGy) and the noise differences from the target noise (1.1 ± 0.9 HU) of the CTDIvol group were significantly lower than those of the weight-based group (2.0 ± 1.0 mGy, 1.8 ± 1.4 HU) (P < 0.001). In contrast, no statistically significant difference was found in area (317.0 ± 136.8 cm(2) vs. 326.3 ± 124.8 cm(2)), mean density (-212.9 ± 53.1 HU vs. -221.1 ± 56.3 HU), and image noise (13.8 ± 2.3 vs. 13.6 ± 1.7 HU) between the weight-based and the CTDIvol groups (P > 0.05). Contrast-enhanced pediatric chest CT with the CTDIvol determined individually by the cross-sectional area and density of the body provides more uniform noise and better dose adaptation to body habitus than does weight-based CT at variable kV levels and with combined tube current modulation.

  13. Modeling ion extraction from a free-plasma surface with a flexible conformal mesh

    NASA Astrophysics Data System (ADS)

    Humphries, Stanley

    2005-04-01

    This paper describes a new method for numerical modeling of extraction of high-current ion beams from a plasma source. The challenge in the application is to satisfy simultaneously requirements for space-charge-limited flow and uniform ion flux. The plasma surface must assume a special shape that is not known in advance. The method involves the use of finite-element techniques coupled with a dynamic conformal mesh. Starting from an initial estimate, the flexible mesh is shifted to achieve uniform flux over the emission surface. The approach achieves high accuracy and has the versatility to handle complex emission surfaces in gridded guns. In contrast to trial-and-error approaches, the method proceeds directly to the optimum solution. The technique can also be applied to determine cathode shapes for uniform-flux electron guns. Benchmark calculations using the Trak two-dimensional ray-tracing code are described. The program automatically carries out the surface search.

  14. Enhanced bioactivity of Mg-Nd-Zn-Zr alloy achieved with nanoscale MgF2 surface for vascular stent application.

    PubMed

    Mao, Lin; Shen, Li; Chen, Jiahui; Wu, Yu; Kwak, Minsuk; Lu, Yao; Xue, Qiong; Pei, Jia; Zhang, Lei; Yuan, Guangyin; Fan, Rong; Ge, Junbo; Ding, Wenjiang

    2015-03-11

    Magnesium (Mg) alloys have revolutionized the application of temporary load-bearing implants as they meet both engineering and medical requirements. However, rapid degradation of Mg alloys under physiological conditions remains the major obstacle hindering the wider use of Mg-based implants. Here we developed a simple method of preparing a nanoscale MgF2 film on Mg-Nd-Zn-Zr (denoted as JDBM) alloy, aiming to reduce the corrosion rate as well as improve the biological response. The corrosion rate of JDBM alloy exposed to artificial plasma is reduced by ∼20% from 0.337 ± 0.021 to 0.269 ± 0.043 mm·y(-1) due to the protective effect of the MgF2 film with a uniform and dense physical structure. The in vitro cytocompatibility test of MgF2-coated JDBM using human umbilical vein endothelial cells indicates enhanced viability, growth, and proliferation as compared to the naked substrate, and the MgF2 film with a nanoscale flakelike feature of ∼200-300 nm presents a much more favorable environment for endothelial cell adhesion, proliferation, and alignment. Furthermore, the animal experiment via implantation of MgF2-coated JDBM stent to rabbit abdominal aorta confirms excellent tissue compatibility of the well re-endothelialized stent with no sign of thrombogenesis and restenosis in the stented vessel.

  15. Improved Uniformity In Thinned Scientific CCDs

    NASA Astrophysics Data System (ADS)

    Winzenread, Rusty; Chiao, Pat; Wang, Weng-Lyang; Robinson, Lloyd B.

    1989-12-01

    Large area image sensors using Charge-Coupled Device (CCD) technology for scientific applications are often thinned and backside illuminated to improve their overall sensitivity and particularly their short wavelength response. The usual method of fabrication is to start with a p-type (high resistivity) epi-layer on a 1)4-type (low resistivity) substrate and chemically etch the device until there is a thin membrane of the desired thickness at or near the p-p+ interface. Variations in the doping concentration at the final back surface because of nonuniform thinning often lead to poor pixel-to-pixel uniformities. Pixel-to-pixel variations of > 100% are not uncommon for incident light at wavelengths of 350 nm on poorly thinned devices. We have developed a thinning process that reduces the pixel-to-pixel variations to < 5% while maintaining a quantum efficiency (QE) of > 40% at 350 nm, when the back surface is charged. Two scientific CCDs are currently made with thiA process, a 404 x 64 array of 52 x 52 gm pixels and a 1200 x 400 array of 27 x 27 gm' pixels. Test results of this process on these two devices will be presented.

  16. Method to produce large, uniform hollow spherical shells

    DOEpatents

    Hendricks, C.D.

    1983-09-26

    The invention is a method to produce large uniform hollow spherical shells by (1) forming uniform size drops of heat decomposable or vaporizable material, (2) evaporating the drops to form dried particles, (3) coating the dried particles with a layer of shell forming material and (4) heating the composite particles to melt the outer layer and to decompose or vaporize the inner particle to form an expanding inner gas bubble. The expanding gas bubble forms the molten outer layer into a shell of relatively large diameter. By cycling the temperature and pressure on the molten shell, nonuniformities in wall thickness can be reduced. The method of the invention is utilized to produce large uniform spherical shells, in the millimeter to centimeter diameter size range, from a variety of materials and of high quality, including sphericity, concentricity and surface smoothness, for use as laser fusion or other inertial confinement fusion targets as well as other applications.

  17. Method of manufacturing hollow members having uniform wall thickness through use of ablation

    DOEpatents

    Anderson, Paul R.; Downs, Raymond L.; Henderson, Timothy M.

    1982-01-01

    A method of manufacturing a hollow structure of uniform wall thickness comprising the steps of selecting or forming a precursor having one wall surface of desired geometry, treating a portion of the precursor consisting of the one wall surface and a uniform depth of material beneath the wall surface to increase resistance to ablation, and then removing by ablation and discarding the remaining or untreated portion of the precursor.

  18. Uniform sampling table method and its applications: establishment of a uniform sampling method.

    PubMed

    Chen, Yibin; Chen, Jiaxi; Wang, Wei

    2013-01-01

    A novel uniform sampling method is proposed in this paper. According to the requirements of uniform sampling, we propose the properties that must be met by analyzing the distribution of samples. Based on this, the proposed uniform sampling method is demonstrated and evaluated strictly by mathematical means such as inference. The uniform sampling tables with respect to Cn(t2) and Cn(t3) are established. Furthermore, a one-dimension uniform sampling method and a multidimension method are proposed. The proposed novel uniform sampling method, which is guided by uniform design theory, enjoys the advantages of simplified use and good representativeness of the whole sample.

  19. Increase in the Hydrophilicity and Lewis Acid-Base Properties of Solid Surfaces Achieved by Electric Gliding Discharge in Humid Air: Effects on Bacterial Adherence

    NASA Astrophysics Data System (ADS)

    Kamgang, J. O.; Naitali, M.; Herry, J.-M.; Bellon-Fontaine, M.-N.; Brisset, J.-L.; Briandet, R.

    2009-04-01

    This study addressed the effects of treatment with gliding discharge plasma on the surface properties of solid materials, as well as the consequences concerning adherence of a model bacterium. As evaluated by contact angles with selected liquids, plasma treatment caused an increase in surface hydrophilicity and in the Lewis acid-base components of the surface energy of all materials tested. These modifications were more marked for low density polyethylene and stainless steel than for polytetrafluoroethylene. After treatment, the hydrophilicity of the materials remained relatively stable for at least 20 days. Moreover, analysis of the topography of the materials by atomic force microscopy revealed that the roughness of both polymers was reduced by glidarc plasma treatment. As a result of all these modifications, solid substrates were activated towards micro-organisms and the adherence of S. epidermidis, a negatively charged Lewis-base and mildly hydrophilic strain selected as the model, was increased in almost all the cases tested.

  20. Buffered Electropolishing – A New Way for Achieving Extremely Smooth Surface Finish on Nb SRF Cavities to be Used in Particle Accelerators

    SciTech Connect

    Hui Tian, Charles Reece, Michael Kelley

    2009-05-01

    Future accelerators require unprecedented cavity performance, which is strongly influenced by interior surface nano-smoothness. Electropolishing (EP) is the technique of choice to be developed for high-field superconducting radio frequency (SRF) cavities. Electrochemical impedance spectroscopy (EIS) and related techniques point to the electropolishing mechanism of Nb in a sulphuric and hydrofluoric acid electrolyte controlled by a compact surface salt film under F- diffusion-limited mass transport control. These and other findings are guiding a systematic characterization to form the basis for cavities process optimization.

  1. Uniform guidelines improve client care.

    PubMed

    Barnett, B

    1994-12-01

    Uniform national guidelines on the delivery of family planning methods and services improve client care, assuming these guidelines are based on current scientific information. Compliance with these guidelines yields safe and efficient delivery of family planning services. Service providers need information, training, supplies, and guidelines to deliver quality services. Guidelines contribute to consistency among family planning programs in different settings. Even though clinics may not provide the same services, the guidelines allow them to provide the same standards of care. Specifically, eligibility criteria, contraindications, and follow-up schedules are the same regardless of the service delivery point. Various international health organizations (such as World Health Organization, USAID, Program for International Training in Health, International Planned Parenthood Federation, and Association for Voluntary Surgical Contraception) have developed guidelines for family planning service delivery. Governments can use these documents to develop national family planning guidelines and policies. They should adapt the guidelines to local needs and consider program resources. After development of the national guidelines, training, workshops, and dissemination of written materials should be provided for policymakers, physicians, nurses, and other health providers. Countries that have either developed or are working to draft their own national guidelines are Cameroon, Ghana, Mexico, and Nepal.

  2. Sample-Based Surface Coloring

    PubMed Central

    Bürger, Kai; Krüger, Jens; Westermann, Rüdiger

    2011-01-01

    In this paper, we present a sample-based approach for surface coloring, which is independent of the original surface resolution and representation. To achieve this, we introduce the Orthogonal Fragment Buffer (OFB)—an extension of the Layered Depth Cube—as a high-resolution view-independent surface representation. The OFB is a data structure that stores surface samples at a nearly uniform distribution over the surface, and it is specifically designed to support efficient random read/write access to these samples. The data access operations have a complexity that is logarithmic in the depth complexity of the surface. Thus, compared to data access operations in tree data structures like octrees, data-dependent memory access patterns are greatly reduced. Due to the particular sampling strategy that is employed to generate an OFB, it also maintains sample coherence, and thus, exhibits very good spatial access locality. Therefore, OFB-based surface coloring performs significantly faster than sample-based approaches using tree structures. In addition, since in an OFB, the surface samples are internally stored in uniform 2D grids, OFB-based surface coloring can efficiently be realized on the GPU to enable interactive coloring of high-resolution surfaces. On the OFB, we introduce novel algorithms for color painting using volumetric and surface-aligned brushes, and we present new approaches for particle-based color advection along surfaces in real time. Due to the intermediate surface representation we choose, our method can be used to color polygonal surfaces as well as any other type of surface that can be sampled. PMID:20616392

  3. Sample-based surface coloring.

    PubMed

    Bürger, Kai; Krüger, Jens; Westermann, Rüdiger

    2010-01-01

    In this paper, we present a sample-based approach for surface coloring, which is independent of the original surface resolution and representation. To achieve this, we introduce the Orthogonal Fragment Buffer (OFB)-an extension of the Layered Depth Cube-as a high-resolution view-independent surface representation. The OFB is a data structure that stores surface samples at a nearly uniform distribution over the surface, and it is specifically designed to support efficient random read/write access to these samples. The data access operations have a complexity that is logarithmic in the depth complexity of the surface. Thus, compared to data access operations in tree data structures like octrees, data-dependent memory access patterns are greatly reduced. Due to the particular sampling strategy that is employed to generate an OFB, it also maintains sample coherence, and thus, exhibits very good spatial access locality. Therefore, OFB-based surface coloring performs significantly faster than sample-based approaches using tree structures. In addition, since in an OFB, the surface samples are internally stored in uniform 2D grids, OFB-based surface coloring can efficiently be realized on the GPU to enable interactive coloring of high-resolution surfaces. On the OFB, we introduce novel algorithms for color painting using volumetric and surface-aligned brushes, and we present new approaches for particle-based color advection along surfaces in real time. Due to the intermediate surface representation we choose, our method can be used to color polygonal surfaces as well as any other type of surface that can be sampled.

  4. Controlling Marangoni-induced instabilities in spin-cast polymer films: How to prepare uniform films.

    PubMed

    Fowler, Paul D; Ruscher, Céline; McGraw, Joshua D; Forrest, James A; Dalnoki-Veress, Kari

    2016-09-01

    In both research and industrial settings spincoating is extensively used to prepare highly uniform thin polymer films. However, under certain conditions, spincoating results in films with non-uniform surface morphologies. Although the spincoating process has been extensively studied, the origin of these morphologies is not fully understood and the formation of non-uniform spin-cast films remains a practical problem. Here we report on experiments demonstrating that the formation of surface instabilities during spincoating is dependent on temperature. Our results suggest that non-uniform spin-cast films form as a result of the Marangoni effect, which describes flow due to surface tension gradients. We find that both the wavelength and amplitude of the pattern increase with temperature. Finally, and most important from a practical viewpoint, the non-uniformities in the film thickness can be entirely avoided simply by lowering the spin coating temperature.

  5. Design of highly uniform spool and bar horns for ultrasonic bonding.

    PubMed

    Kim, Sun-Rak; Lee, Jae Hak; Yoo, Choong D; Song, Jun-Yeob; Lee, Seung S

    2011-10-01

    Although the groove and slot have been widely utilized for horn design to achieve high uniformity, their effects on uniformity have not been analyzed thoroughly. In this work, spool and bar horns for ultrasonic bonding are designed in a systematic way using the design of experiments (DOE) to achieve high amplitude uniformity of the horn. Three-dimensional modal analysis is conducted to predict the natural frequency, amplitude, and stress of the horns, and the DOE is employed to analyze the effects of the groove and slot on the amplitude uniformity. The design equations are formulated to determine the optimum dimensions of the groove and slot, and the uniformity is found to be influenced most significantly by the groove depth and slot width. Displacements of the spool and bar horns were measured using a laser Doppler vibrometer (LDV), and the predicted results are in good agreement with the experimental data.

  6. The symbolism and myth surrounding nurses' uniform.

    PubMed

    Richardson, M

    This article addresses nurses' uniform from the perspective of the symbolic, myth, legend and competing discourse. The analysis touches upon why nurses working with people who have learning disabilities discarded the nurses' uniform and why other nurses may consider doing so, particularly if suitable alternatives exist. The analysis draws from various areas of nursing practice, including the nursing of disabled people, elderly people and people with learning disabilities. Nurses' uniform is revealed as a totem of considerable potency such that to wear a uniform in just any setting or context has to be cautioned. The practicalities of protective clothing are addressed. A differentiation is drawn between uniform and protective clothing such that much of the undesirable symbolism associated with uniform may be discarded with a consequent enhancement of the image of the nurse.

  7. Alignment and Characterization of High Uniformity Imaging Spectrometers

    NASA Technical Reports Server (NTRS)

    Bender, Holly A.; Mouroulis, Pantazis; Eastwood, Michael L.; Green, Robert O.; Geier, Sven; Hochberg, Eric B.

    2011-01-01

    Imaging spectrometers require precise adjustments, in some cases at the sub-micrometer level, in order to achieve auniform response over both the spectral and spatial dimensions. We describe a set of measurement techniques and theircorresponding alignment adjustments to achieve the 95% or higher uniformity specifications required for Earthobservingimaging spectrometers. The methods are illustrated with measurements from the Next Generation Imaging Spectrometer system that has been built at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  8. Uniform Additivity in Classical and Quantum Information

    NASA Astrophysics Data System (ADS)

    Cross, Andrew; Li, Ke; Smith, Graeme

    2017-01-01

    Information theory quantifies the optimal rates of resource interconversions, usually in terms of entropies. However, nonadditivity often makes evaluating entropic formulas intractable. In a few auspicious cases, additivity allows a full characterization of optimal rates. We study uniform additivity of formulas, which is easily evaluated and captures all known additive quantum formulas. Our complete characterization of uniform additivity exposes an intriguing new additive quantity and identifies a remarkable coincidence—the classical and quantum uniformly additive functions with one auxiliary variable are identical.

  9. Hydraulic machine with non-uniform cascade

    NASA Astrophysics Data System (ADS)

    Haluza, M.; Pochylý, F.; Habán, V.

    2012-11-01

    In this article is introduced the sentence of an extension of operational zone of hydraulic machines. The problems of its extending is based on the design of non-uniform cascade. The non-uniform cascade is connected with other factors. The change of own frequency of the runner of a hydraulic machine and pressure pulsations. The suitable construction of non-uniform cascade is introduced on the results of computational simulation and experiment.

  10. Effect of uniform and non-uniform skin temperature on thermal exchanges in water in humans.

    PubMed

    Choi, Jang Kyu; Lee, Hye Sook; Park, Yang Saeng; Shiraki, Keizo

    2003-03-01

    We investigated the effect of uniform (UST) and non-uniform (NUST) skin temperature on thermal exchanges during a 3-h water immersion in five male subjects wearing (NUST) or not wearing (UST) a water-perfused garment. UST was achieved by immersing the nude subject in water up to the neck. For each subject, the water temperature was adjusted to the critical temperature ( T(cw), 31.4 +/- 0.9 degrees C) or 3 degrees C below T(cw) ( T(cw) - 3). NUST was achieved by perfusing different segments of the perfused garment with water of different temperatures. The water temperature of the segment was independently adjusted according to the skin temperature distribution in cold air, the mean skin temperature being the same as the UST. At T(cw) and T(cw) - 3, changes in esophageal and mean skin temperatures were identical in UST and NUST conditions, but the skin temperature of the trunk was higher and that of the limb was lower in the NUST condition. Heat production and the overall skin heat flux at T(cw) were identical in the two conditions, but those at T(cw) - 3 were about 25% lower ( P < 0.05) in NUST than in UST conditions. At T(cw) - 3, the overall tissue insulation was 36% higher ( P < 0.05) in NUST than in UST conditions, mainly because of higher limb insulation. Thermogenesis due to shivering was lower by 62% ( P < 0.05) in NUST than in UST. We conclude that the NUST condition increased tissue insulation and suppressed shivering. This suggests that a high skin temperature of the trunk attenuates shivering in cold water and increases the ability to defend body temperature more economically in cold water.

  11. Optimization of energy harvesting based on the uniform deformation of piezoelectric ceramic

    NASA Astrophysics Data System (ADS)

    Liu, Yaoze; Yang, Tongqing; Shu, Fangming

    2016-09-01

    Since the piezoelectric properties were used for energy harvesting, almost all forms of energy harvester needs to be bonded with a mass block to achieve pre-stress. In this article, disc type piezoelectric energy harvester is chosen as the research object and the relationship between mass bonding area and power output is studied. It is found that if the bonding area is changed as curved, which is usually complanate in previous studies, the deformation of the circular piezoelectric ceramic is more uniform and the power output is enhanced. In order to test the change of the deformation, we spray several homocentric annular electrodes on the surface of a piece of bare piezoelectric ceramic and the output of each electrode is tested. Through this optimization method, the power output is enhanced to more than 11mW for a matching load about 24kΩ and a tip mass of 30g at its resonant frequency of 139Hz.

  12. Periodic envelopes of waves over non-uniform depth

    NASA Astrophysics Data System (ADS)

    Rajan, Girish K.; Bayram, Saziye; Henderson, Diane M.

    2016-04-01

    The envelope of narrow-banded, periodic, surface-gravity waves propagating in one dimension over water of finite, non-uniform depth may be modeled by the Djordjević and Redekopp ["On the development of packets of surface gravity waves moving over an uneven bottom," Z. Angew. Math. Phys. 29, 950-962 (1978)] equation (DRE). Here we find five approximate solutions of the DRE that are in the form of Jacobi-elliptic functions and discuss them within the framework of ocean swell. We find that in all cases, the maximum envelope-amplitude decreases/increases when the wave group propagates on water of decreasing/increasing depth. In the limit of the elliptic modulus approaching one, three of the solutions reduce to the envelope soliton solution. In the limit of the elliptic modulus approaching zero, two of the solutions reduce to an envelope-amplitude that is uniform in an appropriate reference frame.

  13. Back to the Basics: In Defense of Achievement (and Achievement Tests) in College Admissions

    ERIC Educational Resources Information Center

    Geiser, Saul

    2009-01-01

    In this article, the author describes the growth and acceptance of achievement tests, such as the Scholastic Aptitude Test (SAT), over the past century, advocating that many SAT claims of equity, uniformity, technical reliability, and prediction, over traditional measures of academic achievement have been found to be illusory. Summarizing a series…

  14. Evidence for a Standardized Preadmission Showering Regimen to Achieve Maximal Antiseptic Skin Surface Concentrations of Chlorhexidine Gluconate, 4%, in Surgical Patients.

    PubMed

    Edmiston, Charles E; Lee, Cheong J; Krepel, Candace J; Spencer, Maureen; Leaper, David; Brown, Kellie R; Lewis, Brian D; Rossi, Peter J; Malinowski, Michael J; Seabrook, Gary R

    2015-11-01

    To reduce the amount of skin surface bacteria for patients undergoing elective surgery, selective health care facilities have instituted a preadmission antiseptic skin cleansing protocol using chlorhexidine gluconate. A Cochrane Collaborative review suggests that existing data do not justify preoperative skin cleansing as a strategy to reduce surgical site infection. To develop and evaluate the efficacy of a standardized preadmission showering protocol that optimizes skin surface concentrations of chlorhexidine gluconate and to compare the findings with the design and methods of published studies on preoperative skin preparation. A randomized prospective analysis in 120 healthy volunteers was conducted at an academic tertiary care medical center from June 1, 2014, to September, 30, 2014. Data analysis was performed from October 13, 2014, to October 27, 2014. A standardized process of dose, duration, and timing was used to maximize antiseptic skin surface concentrations of chlorhexidine gluconate applied during preoperative showering. The volunteers were randomized to 2 chlorhexidine gluconate, 4%, showering groups (2 vs 3 showers), containing 60 participants each, and 3 subgroups (no pause, 1-minute pause, or 2-minute pause before rinsing), containing 20 participants each. Volunteers used 118 mL of chlorhexidine gluconate, 4%, for each shower. Skin surface concentrations of chlorhexidine gluconate were analyzed using colorimetric assay at 5 separate anatomic sites. Individual groups were analyzed using paired t test and analysis of variance. Preadmission showers using chlorhexidine gluconate, 4%. The primary outcome was to develop a standardized approach for administering the preadmission shower with chlorhexidine gluconate, 4%, resulting in maximal, persistent skin antisepsis by delineating a precise dose (volume) of chlorhexidine gluconate, 4%; duration (number of showers); and timing (pause) before rinsing. The mean (SD) composite chlorhexidine gluconate

  15. A Smart Cage With Uniform Wireless Power Distribution in 3D for Enabling Long-Term Experiments With Freely Moving Animals.

    PubMed

    Mirbozorgi, S Abdollah; Bahrami, Hadi; Sawan, Mohamad; Gosselin, Benoit

    2016-04-01

    This paper presents a novel experimental chamber with uniform wireless power distribution in 3D for enabling long-term biomedical experiments with small freely moving animal subjects. The implemented power transmission chamber prototype is based on arrays of parallel resonators and multicoil inductive links, to form a novel and highly efficient wireless power transmission system. The power transmitter unit includes several identical resonators enclosed in a scalable array of overlapping square coils which are connected in parallel to provide uniform power distribution along x and y. Moreover, the proposed chamber uses two arrays of primary resonators, facing each other, and connected in parallel to achieve uniform power distribution along the z axis. Each surface includes 9 overlapped coils connected in parallel and implemented into two layers of FR4 printed circuit board. The chamber features a natural power localization mechanism, which simplifies its implementation and ease its operation by avoiding the need for active detection and control mechanisms. A single power surface based on the proposed approach can provide a power transfer efficiency (PTE) of 69% and a power delivered to the load (PDL) of 120 mW, for a separation distance of 4 cm, whereas the complete chamber prototype provides a uniform PTE of 59% and a PDL of 100 mW in 3D, everywhere inside the chamber with a size of 27×27×16 cm(3).

  16. Uniform Deterministic Discrete Method for three dimensional systems

    NASA Astrophysics Data System (ADS)

    Li, Ben-Wen; Tao, Wen-Quan; Nie, Yu-Hong

    1997-06-01

    For radiative direct exchange areas in three dimensional system, the Uniform Deterministic Discrete Method (UDDM) was adopted. The spherical surface dividing method for sending area element and the regular icosahedron for sending volume element can meet with the direct exchange area computation of any kind of zone pairs. The numerical examples of direct exchange area in three dimensional system with nonhomogeneous attenuation coefficients indicated that the UDDM can give very high numerical accuracy.

  17. 46 CFR 310.11 - Cadet uniforms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Cadet uniforms. 310.11 Section 310.11 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION TRAINING MERCHANT MARINE TRAINING Regulations and Minimum Standards for State, Territorial or Regional Maritime Academies and Colleges § 310.11 Cadet uniforms. Cadet...

  18. School Dress Codes and Uniform Policies.

    ERIC Educational Resources Information Center

    Anderson, Wendell

    2002-01-01

    Opinions abound on what students should wear to class. Some see student dress as a safety issue; others see it as a student-rights issue. The issue of dress codes and uniform policies has been tackled in the classroom, the boardroom, and the courtroom. This Policy Report examines the whole fabric of the debate on dress codes and uniform policies…

  19. Student Dress Codes and Uniforms. Research Brief

    ERIC Educational Resources Information Center

    Johnston, Howard

    2009-01-01

    According to an Education Commission of the States "Policy Report", research on the effects of dress code and school uniform policies is inconclusive and mixed. Some researchers find positive effects; others claim no effects or only perceived effects. While no state has legislatively mandated the wearing of school uniforms, 28 states and…

  20. School Uniform Policies: Students' Views of Effectiveness.

    ERIC Educational Resources Information Center

    McCarthy, Teresa M.; Moreno, Josephine

    2001-01-01

    Focus-group interviews of New York City middle-school students about their perceptions of the effectiveness of the school-uniform policy. Finds that students' perceptions of the effects of school-uniform policy on school culture varied considerably with those intended by the principal. (Contains 40 references.) (PKP)

  1. School Uniforms and Discourses on Childhood.

    ERIC Educational Resources Information Center

    Bodine, Ann

    2003-01-01

    This ethnographic study examined the introduction of school uniforms in the public schools of one California city. Findings indicated that the uniform issue intersected with issues such as student safety and violence, family stress, egalitarianism, competitive dressing, and a power struggle over shaping the childhood environment. It was concluded…

  2. A School Uniform Program That Works.

    ERIC Educational Resources Information Center

    Loesch, Paul C.

    1995-01-01

    According to advocates, school uniforms reduce gang influence, decrease families' clothing expenditures, and help mitigate potentially divisive cultural and economic differences. Aiming to improve school climate, a California elementary school adopted uniforms as a source of pride and affiliation. This article describes the development of the…

  3. Coded aperture imaging with uniformly redundant arrays

    DOEpatents

    Fenimore, Edward E.; Cannon, Thomas M.

    1980-01-01

    A system utilizing uniformly redundant arrays to image non-focusable radiation. The uniformly redundant array is used in conjunction with a balanced correlation technique to provide a system with no artifacts such that virtually limitless signal-to-noise ratio is obtained with high transmission characteristics. Additionally, the array is mosaicked to reduce required detector size over conventional array detectors.

  4. Coded aperture imaging with uniformly redundant arrays

    DOEpatents

    Fenimore, Edward E.; Cannon, Thomas M.

    1982-01-01

    A system utilizing uniformly redundant arrays to image non-focusable radiation. The uniformly redundant array is used in conjunction with a balanced correlation technique to provide a system with no artifacts such that virtually limitless signal-to-noise ratio is obtained with high transmission characteristics. Additionally, the array is mosaicked to reduce required detector size over conventional array detectors.

  5. Diversity in representations; uniformity in learning.

    PubMed

    Danks, David; Rose, David

    2010-06-01

    Henrich et al.'s conclusion that psychologists ought not assume uniformity of psychological phenomena depends on their descriptive claim that there is no pattern to the great diversity in psychological phenomena. We argue that there is a pattern: uniformity of learning processes (broadly construed), and diversity of (some) mental contents (broadly construed).

  6. Testing for uniformity in multidimensional data.

    PubMed

    Smith, S P; Jain, A K

    1984-01-01

    Testing for uniformity in multidimensional data is important in exploratory pattern analysis, statistical pattern recognition, and image processing. The goal of this paper is to determine whether the data follow the uniform distribution over some compact convex set in K-dimensional space, called the sampling window. We first provide a simple, computationally efficient method for generating a uniformly distributed sample over a set which approximates the convex hul of the data. We then test for uniformity by comparing this generated sample to the data by using Friedman-Rafsky's minimal spanning tree (MST) based test. Experiments with both simulated and real data indicate that this MST-based test is useful in deciding if data are uniform.

  7. Study on the method of combined uniform removal in fabrication of large aspheric mirror

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Zeng, Zhige; Wu, Fan

    2016-10-01

    In the processing of large aspheric mirror, uniform removal means the process of equal removal at the whole surface in grinding and rough polishing stage. It aims to remove the subsurface damage layer at forming and grinding stage. It also smoothes the surface for reducing even eliminating mid-and-high-frequency error on the mirror. The combined processing method is using different diameter of laps by spatial frequency error model of reasonable matching in fabrication of workpiece. In this paper, the uniform removal method of combination NC manipulator and the Computer Controlled Active Lap is used. From the ring removal function model, the processing of combined uniform removal is simulated and analyzed. Compared with the CCAL uniform removal processing, it can get the much better uniform removal effect.

  8. Turbulent boundary layer control at moderate Reynolds numbers by means of uniform blowing/suction

    NASA Astrophysics Data System (ADS)

    Kametani, Yukinori; Fukagata, Koji; Orlu, Ramis; Schlatter, Philipp

    2015-11-01

    The effect of uniform blowing or suction from the wall on a spatially developing turbulent boundary layer has been studied in order to use them ultimately for flow control on the surface of high-speed vehicles. In the present study, a series of large eddy simulations is performed to investigate the effects of uniform blowing/suction on the skin friction drag as well as the scale of turbulent structures at moderate Reynolds numbers up to Reθ = 2500, based on free-stream velocity, U∞, and momentum thickness, θ. The amplitude of blowing or suction is fixed to 0.1% of U∞with different streamwise ranges of the control region. While the Reynolds shear and normal stresses and their spectral energy distributions are increased by blowing and decreased by suction, in particular, in the outer region, the FIK identity reveals that drag reduction (DR) or enhancement (DE) are mainly linked to changes in the spatial development of the mean wall-normal convection term rather than the contribution from the Reynolds shear stress. Despite the weak amplitude of the control, over 10% of DR and DE are achieved by blowing and suction, respectively. In case of blowing, the mean DR rate increases as the blowing region extends because the local reduction rate grows in the streamwise direction. Grant-in-Aid for Scientific Research (C) (No. 25420129), Grant-in-Aid for JSPS Fellow (No. 24-3450), the Knut an Alice Wallenberg Foundation.

  9. Fast precipitation of uniform CaCO3 nanospheres and their transformation to hollow hydroxyapatite nanospheres.

    PubMed

    Wang, Yongsheng; Moo, Ying Xin; Chen, Chunping; Gunawan, Poernomo; Xu, Rong

    2010-12-15

    Shape-controlled synthesis of calcium carbonate with specific polymorphs can be achieved by the assistance of organic additives. In this study, highly uniform nanosized calcium carbonate spheres were synthesized by a fast precipitation method in the presence of a simple polymer, poly(styrene sulfonate) (PSS). The polymorph of the synthesized calcium carbonate products changes from pure calcite in PSS-free reactions to vaterite in PSS-containing (1-50 g/L) reactions. The effect of PSS on the formation of vaterite can be attributed to the two aspects: decrease of driving force by reducing the interfacial energy, and phase stabilization effect caused by the adsorbed PSS. A higher PSS concentration (50 g/L) results in highly uniform vaterite nanospheres of 400-500 nm in diameter. Furthermore, PSS is found more effective to induce the formation of vaterite in the Ca(2+)-rich reaction condition (Ca(2+):CO(3)(2-)=5:1) than in the CO(3)(2-)-rich conditions (Ca(2+):CO(3)(2-)=1:5). It has also been found that different mixing mode of the calcium and carbonate precursor solutions has a significant influence on the size distribution of the products. Finally, with a controlled anion-exchange method, the as-prepared vaterite nanospheres can be easily transformed to hollow hydroxyapatite spheres, which exhibit great potential to be used as the drug carriers due to their considerably high surface area and biocompatibility.

  10. Method For Plasma Source Ion Implantation And Deposition For Cylindrical Surfaces

    DOEpatents

    Fetherston, Robert P. , Shamim, Muhammad M. , Conrad, John R.

    1997-12-02

    Uniform ion implantation and deposition onto cylindrical surfaces is achieved by placing a cylindrical electrode in coaxial and conformal relation to the target surface. For implantation and deposition of an inner bore surface the electrode is placed inside the target. For implantation and deposition on an outer cylindrical surface the electrode is placed around the outside of the target. A plasma is generated between the electrode and the target cylindrical surface. Applying a pulse of high voltage to the target causes ions from the plasma to be driven onto the cylindrical target surface. The plasma contained in the space between the target and the electrode is uniform, resulting in a uniform implantation or deposition of the target surface. Since the plasma is largely contained in the space between the target and the electrode, contamination of the vacuum chamber enclosing the target and electrodes by inadvertent ion deposition is reduced. The coaxial alignment of the target and the electrode may be employed for the ion assisted deposition of sputtered metals onto the target, resulting in a uniform coating of the cylindrical target surface by the sputtered material. The independently generated and contained plasmas associated with each cylindrical target/electrode pair allows for effective batch processing of multiple cylindrical targets within a single vacuum chamber, resulting in both uniform implantation or deposition, and reduced contamination of one target by adjacent target/electrode pairs.

  11. 78 FR 48366 - Civilian Health and Medical Program of the Uniformed Services (CHAMPUS); TRICARE Uniform Health...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-08

    ... Services (CHAMPUS); TRICARE Uniform Health Maintenance Organization (HMO) Benefit--Prime Enrollment Fee... proposed rule would establish an exception to the usual rule that TRICARE Prime enrollment fees are uniform... Sponsors and Medically Retired Uniformed Services Members and their Dependents enrolled in Prime to be...

  12. 78 FR 34292 - Civilian Health and Medical Program of the Uniformed Services (CHAMPUS); TRICARE Uniform Health...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-07

    ... Services (CHAMPUS); TRICARE Uniform Health Maintenance Organization (HMO) Benefit--Prime Enrollment Fee... proposed rule would establish an exception to the usual rule that TRICARE Prime enrollment fees are uniform... Sponsors and Medically Retired Uniformed Services Members and their Dependents enrolled in Prime to be...

  13. Uniformity of material in the SME and MFT

    SciTech Connect

    Plodinec, M.J.

    1992-05-29

    The DWPF will satisfy the product consistency specification in the Waste Acceptance Preliminary Specifications through control of the chemical composition of the glass product. This control will be achieved by ensuring that each batch of feed in the Slurry Mix Evaporator (SME) will produce glass which satisfies the specification. The purpose of this report is to determine what degree of uniformity can be expected of material in the SME and Metter Feed Tank (MFT). These vessels were designed based on a design development process which had proven successful for similar hard-to-mix feeds in the past. This process resulted in a design of the SME and MFT agitation systems which was intended to provide highly uniform melter feed material. Based on the results of extensive tests in protoypic equipment, the SME and MFT designs have met this design goal.

  14. Clonal propagation of chemically uniform fennel plants through somatic embryoids.

    PubMed

    Miura, Y; Fukui, H; Tabata, M

    1987-02-01

    Somatic embryoids obtained from cell suspension cultures of fennel in Linsmaier-Skoog medium containing 2,4-D and kinetin readily developed into plantlets when plated on a hormone-free agar medium. These plants were transplanted to the field to be tested for the uniformity of the chemically as well as the morphologically important characteristics of fruits. The results of field trials conducted for two years have confirmed that the clonal plants derived from somatic embryoids are remarkably uniform in all the characteristics examined in comparison with the control plants propagated through seeds. It is suggested, therefore, that the quality control of fennel fruits used for spice or medicine could be achieved by means of clonal propagation through somatic embryoids.

  15. Chemical Sintering Generates Uniform Porous Hyaluronic Acid Hydrogels

    PubMed Central

    Cam, Cynthia; Segura, Tatiana

    2014-01-01

    Implantation of scaffolds for tissue repair has been met with limited success primarily due to the inability to achieve vascularization within the construct. Many strategies have shifted to incorporate pores into these scaffolds to encourage rapid cellular infiltration and subsequent vascular ingrowth. We utilized an efficient chemical sintering technique to create a uniform network of polymethyl methacrylate (PMMA) microspheres for porous hyaluronic acid hydrogel formation. The porous hydrogels generated from chemical sintering possessed comparable pore uniformity and interconnectivity as the commonly used non- and heat sintering techniques. Moreover, similar cell response to the porous hydrogels generated from each sintering approach was observed in cell viability, spreading, proliferation in vitro, as well as, cellular invasion in vivo. We propose chemical sintering of PMMA microspheres using a dilute acetone solution as an alternative method to generating porous hyaluronic acid hydrogels since it requires equal or ten-fold less processing time as the currently used non-sintering or heat sintering technique, respectively. PMID:24120847

  16. Uniform asymptotic formula for the Aharonov Bohm wavefield

    NASA Astrophysics Data System (ADS)

    Hannay, J. H.

    2016-06-01

    A uniform asymptotic formula for the Aharonov-Bohm wavefield (that of a plane quantum wave scattered by a thin straight solenoid) far away from the solenoid is obtained in a direct way. Actually quite good accuracy is achieved even down to one wavelength away. The error is numerically of order radius^(-3/2) for all values of polar angle, including directly forwards. Several previous formulas, uniform and otherwise, for the far field limit exist in the literature. All contain the essential ingredient: the Fresnel integral (complex error function), but ordinarily the error in these formulas is of order radius^(-1/2) in the forwards direction where the Fresnel contribution is most important.

  17. High performance electrospinning system for fabricating highly uniform polymer nanofibers

    NASA Astrophysics Data System (ADS)

    Munir, Muhammad Miftahul; Iskandar, Ferry; Khairurrijal, Okuyama, Kikuo

    2009-02-01

    A high performance electrospinning system has been successfully developed for production of highly uniform polymer nanofibers. The electrospinning system employed a proportional-integral-derivative control action to maintain a constant current during the production of polyvinyl acetate (PVAc) nanofibers from a precursor solution prepared by dissolution of the PVAc powder in dimethyl formamide so that high uniformity of the nanofibers was achieved. It was found that the cone jet length observed at the end of the needle during the injection of the precursor solution and the average diameter of the nanofibers decreased with decreasing Q /I, where Q is the flow rate of the precursor solution of the nanofibers and I is the current flowing through the electrospinning system. A power law obtained from the relation between the average diameter and Q /I is in accordance with the theoretical model.

  18. Soesterberg, Netherlands. Revised Uniform Summary of Surface Weather Observations (RUSSWO)

    DTIC Science & Technology

    1978-07-13

    10 2. .0 ___ _ _ 0___3 7 * 1. z 2.4 1 1.4 o~ I__ 7l 10o W’oW ISO 1 1;. * 1 ______ 4. 90, NW . . * 1.0 14 __ _ __ __ __ 1191 NNW . 9 ________2 10...4~ .1L1 ESE .9 1*2 .... 1*1 ’. __0 _ __ _ ___4 5~.9 SE .0! ISO 1.0 ;3...... to.. 3,2_ 5__ e__ a___ 1. SSE 1.6 1.4 1.3 ’. 4 .. _______ ______ 4.6...71,5~ 11.7 72. i.dJZ 7t1292 2500 -20.8 40.4 45.6 494-59.f9 62.9 6993 71.9 73.4 74.4174.6i 74.7 75.1 75.1 , 7 5 p 2 22000 22.6 43.7 49,0,53.2 64#6 67.7

  19. Revised Uniform Summary of Surface Weather Observations - Chiangmai, Thailand

    DTIC Science & Technology

    1972-12-01

    vW r W ft lq~l 0O 4 b D P- II - II V-If- II -f l I’-# -- f...r zu * - Do Jx ~ #g ,~ vw - IMM MVWXS4 0tO&0 ASMOA V1)S9- 9w wwa CviAs -,I I w co C., r% l I $ II D- 00 9. ’ o U [ ’ x a% -4 ee. * I ,. ,,,,,lft m 1...Springfield, Virginia 22161 .¢.,-. 4 ~ < - * •.. . LiI 129 < oo v LfLA 0 0 IL 5 in I.- D L J InIn% II 5u. 0 u 00C’~. U o~cLM Review and A

  20. Keesler AFB, Mississippi. Revised Uniform Summary of Surface Weather Observations.

    DTIC Science & Technology

    1986-11-01

    99 1 141 jUl v 3 av 1,, 1 4l 63 b6 7c 7P b4 87 91 94 92 94 86 7S b6 94 C4 69 67 7, -- 6 -97-- - VT . .8-4 -T T 7T 97 I5 71 71 77 8 80 b9 93 90 88 83 ...803 3-7 80 ; 8.3 - ’A 15.01 70.2 76.6 7., 81 .! 82 .U 62.4 82.6 8 .8 82.8 87.9 82.9 82.9 S2.9 62.9 8Z.9 F i Lj? Of -7-1 U--7. -- R-3 30 639 8.8 8. 3. AT...87.7 F 9J7 74.5 61.2 83 .S 86.8 87.3 88.3 86.4 88.4 88.4 88.4 88. 88.5 88.6 88.6 88.6 CF FJ 74.9 81.7 84.1 67.4 b8 .u 88.9 89.0 69.0 89.C 89.0 89.1 82

  1. Nellis AFB, Nevada. Revised Uniform Summary of Surface Weather Observations.

    DTIC Science & Technology

    1986-11-01

    OSOtfTf 7L7nAL CLIMATOLOGY .ANCH ’:’ EAcmER WEATHER CONDITIONS 𔃼 3,,bS NELLI AFA NV 76-16 ALL ST rA AT -NAT1E YEARS .. (NTH PEPCENTAGE FPEOUENCY OF...NIUPLP; 723865 STATI0 NAME NELLIS AFA NV PE 1OO OF RECORD: 49-8b TOTAL MONTHLY SNOWFALL IN INCHES I -O-N-T-H-S- ALL YIA’ JAN F Ra APR MAY JUN JUL AUG...VERSUS WIND SPEEO USAFETAC FROM HOURLY OBSERVATIONS AIR WFATHSR SERVICL/MAC STATION NUMRLR: 723965 STATION NAME: NELLI AFA NV PERlOD Of RECORD: 77-S6 MONTH

  2. Quantification of perceived macro-uniformity

    NASA Astrophysics Data System (ADS)

    Lee, Ki-Youn; Bang, Yousun; Choh, Heui-Keun

    2011-01-01

    Macro-uniformity refers to the subjective impression of overall uniformity in the print sample. By the efforts of INCITS W1.1 team, macro-uniformity is categorized into five types of attributes: banding, streaks, mottle, gradients, and moiré patterns, and the ruler samples are generated with perceptual scales. W1.1 macro-uniformity ruler is useful for judging the levels of print defect, but it is not an easy task to reproduce the samples having the same perceptual scales at different times in different places. An objective quantification method is more helpful and convenient for developers to analyze print quality and design printing system components. In this paper, we propose a method for measuring perceived macro-uniformity for a given print using a flat-bed scanner. First, banding, 2D noise, and gradients are separately measured, and they are converted to the perceptual scales based on subjective results of each attribute. The correlation coefficients between the measured values of the attributes and the perceptual scales are 0.92, 0.97, and 0.86, respectively. Another subjective test is performed to find the relationship between the overall macro-uniformity and the three attributes. The weighting factors are obtained by the experimental result, and the final macro-uniformity grade is determined by the weighted sums of each attribute.

  3. Chirped Pulse Microwave Spectroscopy in Pulsed Uniform Supersonic Flows

    NASA Astrophysics Data System (ADS)

    Abeysekera, Chamara; Oldham, James; Prozument, Kirill; Joalland, Baptiste; Park, Barratt; Field, Robert W.; Sims, Ian; Suits, Arthur; Zack, Lindsay

    2014-06-01

    We present preliminary results describing the development of a new instrument that combines two powerful techniques: Chirped Pulse-Fourier Transform MicroWave (CP-FTMW) spectroscopy and pulsed uniform supersonic flows. It promises a nearly universal detection method that can deliver quantitative isomer, conformer, and vibrational level specific detection, characterization of unstable reaction products and intermediates and perform unique spectroscopic, kinetics and dynamics measurements. We have constructed a new high-power K_a-band, 26-40 GHz, chirped pulse spectrometer with sub-MHz resolution, analogous to the revolutionary CP-FTMW spectroscopic technique developed in the Pate group at University of Virginia. In order to study smaller molecules, the E-band, 60-90 GHz, CP capability was added to our spectrometer. A novel strategy for generating uniform supersonic flow through a Laval nozzle is introduced. High throughput pulsed piezo-valve is used to produce cold (30 K) uniform flow with large volumes of 150 cm^3 and densities of 1014 molecules/cm3 with modest pumping facilities. The uniform flow conditions for a variety of noble gases extend as far as 20 cm from the Laval nozzle and a single compound turbo-molecular pump maintains the operating pressure. Two competing design considerations are critical to the performance of the system: a low temperature flow is needed to maximize the population difference between rotational levels, and high gas number densities are needed to ensure rapid cooling to achieve the uniform flow conditions. At the same time, collision times shorter than the chirp duration will give inaccurate intensities and reduced signal levels due to collisional dephasing of free induction decay. Details of the instrument and future directions and challenges will be discussed.

  4. External view construction for database uniformization

    NASA Technical Reports Server (NTRS)

    Grant, J.

    1984-01-01

    Database uniformization refers to the building of a common user interface facility to support uniform access to any or all of a collection of distributed heterogeneous databases. A proposed solution for database uniformization includes a global data manager which accepts a user's query on the user's global view and returns the results by consulting the various databases. In this paper the external-to-conceptual mapping component of the global data manager is described and the design using portions of sample NASA GSFC databases is illustrated with typical applications.

  5. Inkjet deposition of alkanethiolate monolayers and DNA oligonucleotides on gold: evaluation of spot uniformity by wet etching.

    PubMed

    Bietsch, Alexander; Hegner, Martin; Lang, Hans Peter; Gerber, Christoph

    2004-06-08

    Inkjet printing allows localized, contact-free deposition of liquids onto arbitrary substrates. In this article we demonstrate the fast formation of high-quality self-assembled monolayers (SAMs) on gold surfaces. Using a selective etch process, we verify the uniformity of the deposited spots. A direct comparison with microcontact-printed SAMs on Au revealed similar resist quality as inkjet-deposited alkanethiolate SAMs. Likewise, inkjet printing of thiol-functionalized and non-thiolated single-stranded DNA oligomers formed molecular layers protecting Au from etchants. For all compounds used, we achieved etched patterns that were homogeneous and free of defects. These results indicate that an inkjet is a convenient tool for surface functionalization and the direct writing of molecular films and resists.

  6. Regulation of size and uniformity of In2O3 nanooctahedra

    NASA Astrophysics Data System (ADS)

    Yan, Y. G.; Li, C. Y.; Zhou, L. X.; Xiong, W.; Zhang, J.

    2016-07-01

    Rational regulation of the size and uniformity of nanoparticles has drawn great interests and shown widespread application, but this cannot be simply achieved by the vapor route. In this work, by adopting a chemical vapor deposition approach, the growth process was intricately regulated to guide the reagent supersaturation, and the large-scale growth of uniform-sized In2O3 nanooctahedra was realized. A one-time nucleation and synchronous growth mode controlled by the reagent supersaturation ratio is proposed to be responsible for the uniformity of size. Furthermore, a series of comparative experiments were conducted to study the size dependence on reaction duration, and temperature difference between the heating and depositing zones. This study demonstrates a feasible approach to prepare uniform-sized nanoparticles through precisely controlling the crystal growth process, and the developed growth strategy could be generalized to synthesize uniform-sized nanostructures of other material systems.

  7. Modeling and Analysis of Non-Uniform Honeycomb Structures Based on Topology Optimization

    NASA Astrophysics Data System (ADS)

    Jin, Xin; Li, Guoxi; Zhang, Meng; Gong, Jingzhong

    2017-03-01

    Honeycomb structure infilling is an important way to achieve lightweight. Focusing on the deficiency of the non-optimized macro-material distribution in uniform honeycomb structures, a modeling method of non-uniform honeycomb structures based on topology optimization was proposed. The loaded component was topology-optimized and the density results were mapped to the relative density matrix of cells. The rapid and automatic modeling of non-uniform honeycomb structures was realized with the using of User-Defined Features and the cyclic definitions of the reference datums. The simulation results show that the mechanic performance of non-uniform honeycomb structures is better than uniform honeycomb structures and the efficiency of the proposed method is validated.

  8. LED uniform illumination system for DMD-based confocal microscopy

    NASA Astrophysics Data System (ADS)

    Xiao, Kaimin; Hou, Wenmei; Xu, Qixin; Peng, Bofang

    2013-10-01

    Due to the coherence of laser light source it could produce coherent noise in parallel confocal microscopy based on Digital Micromirror Device (DMD) and thus affect the resolution. LED light source instead of the laser light source can give full play because of its incoherence characterization. In this paper, free-form surface lens is used for LED secondary optics design. According to the LED characteristics and the law of refraction, we have established differential equations of free-form surface. We solved equations with the method of Runge-Kutta by Matlab and the model was built in Tracepro for optical simulation. The results show that the uniformity on the DMD is better than 90% and the lighting efficiency is higher than before. The measured data show us a much more uniform illumination on DMD and LED uniform illumination system successfully avoided the gray error which was caused by the uneven illumination. The LED driver circuit using DC power supply provides us a more stable light source. The axial optical tomography is more accurate and the reconstruction of three-dimensional image is more clearer.

  9. Uniform National Discharge Standards (UNDS): Outreach

    EPA Pesticide Factsheets

    Describes the Federalism and Tribal consultation efforts related to the Uniform National Discharge Standards (UNDS) and links to copies of each presentation, both to state and local representatives, as well as federally-recognized tribes.

  10. Effects of beam irregularity on uniform scanning

    NASA Astrophysics Data System (ADS)

    Kim, Chang Hyeuk; Jang, Sea duk; Yang, Tae-Keun

    2016-09-01

    An active scanning beam delivery method has many advantages in particle beam applications. For the beam is to be successfully delivered to the target volume by using the active scanning technique, the dose uniformity must be considered and should be at least 2.5% in the case of therapy application. During beam irradiation, many beam parameters affect the 2-dimensional uniformity at the target layer. A basic assumption in the beam irradiation planning stage is that the shape of the beam is symmetric and follows a Gaussian distribution. In this study, a pure Gaussian-shaped beam distribution was distorted by adding parasitic Gaussian distribution. An appropriate uniform scanning condition was deduced by using a quantitative analysis based on the gamma value of the distorted beam and 2-dimensional uniformities.

  11. Uniforms, status and professional boundaries in hospital.

    PubMed

    Timmons, Stephen; East, Linda

    2011-11-01

    Despite their comparative neglect analytically, uniforms play a key role in the delineation of occupational boundaries and the formation of professional identity in healthcare. This paper analyses a change to the system of uniforms in one UK hospital, where management have required all professions (with the exception of doctors) to wear the same 'corporate' uniform. Focus groups were conducted with the professionals and patients. We analyse this initiative as a kind of McDonaldisation, seeking to create a new 'corporate' worker whose allegiance is principally to the organisation, rather than a profession. Our findings show how important uniforms are to their wearers, both in terms of the defence of professional boundaries and status, as well as the construction of professional identity.

  12. 7 CFR 29.3563 - Uniformity.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... INSPECTION Standards Official Standard Grades for Dark Air-Cured Tobacco (u.s. Types 35, 36, 37 and Foreign... tobacco as it is prepared for market. Uniformity is expressed in grade specifications as a percentage....

  13. Uniform National Discharge Standards (UNDS): Fact Sheet

    EPA Pesticide Factsheets

    The factsheet describes the Uniform National Discharge Standards and explains what vessels are regulated and how the rulemaking will impact states. It details the batch and phase approach to rulemaking and lists the first batch of vessel discharges.

  14. Acoustic power in non-uniform lined ducts

    NASA Astrophysics Data System (ADS)

    Eversman, Walter

    2008-06-01

    A definition of acoustic power in conservation form in lined infinitely long uniform ducts is extended to include axially symmetric non-uniform ducts with potential mean flow and finite length lining. The definition includes a contribution at the lined boundary. Benchmarking is accomplished by verification of acoustic power conservation in the case of a purely reactive lining. Calculations in the case of reactively lined ducts show that intense acoustic gradients near the lined surface can occur, and contributions to acoustic power from the boundary power term become relatively large. This observed behavior diminishes as the resistive component of lining impedance is increased. Power calculations for propagation and radiation from a typical turbo-fan inlet and equivalent calculations for an infinite duct propagation model of the same inlet contour are compared. Results are remarkably similar for the case considered, though it is noted that this conclusion is geometry dependent.

  15. Development and application of a uniform testing procedure for griddles

    SciTech Connect

    Saltmarch, M. . Dept. of Nutrition and Food Services)

    1989-12-01

    This research report compares the performance of two single-sided, thermostatically controlled gas griddles when tested in accordance with a Uniform Testing Procedure (UTP) developed by the contractor, Pacific Gas and Electric Company (PG E). Variables reported for each griddle include preheat time and energy consumption, idle-energy consumption, cooking-energy consumption, cooking capacity, cooking-energy efficiency, water-boil efficiency, and the temperature uniformity of the cooking surface. The application of synthetic food models, as a test food alternative to hamburger patties, was investigated. The energy performance of the griddles when tested under controlled, laboratory-style conditions is compared to the performance of the same griddles used for menu production at PG E's Learning Center in San Ramon, California. The UTP for griddles developed in this research project is documented in this report. The UTP has been submitted to the ASTM Committee F-26 on Food Service Equipment for consideration as an official ASTM Test Method.

  16. Laminar boundary layers with uniform shear cross flow

    NASA Astrophysics Data System (ADS)

    Weidman, Patrick

    2017-03-01

    Laminar boundary layers with fully developed uniform shear cross flows are considered. The first streamwise laminar flow is a Blasius boundary layer flow, the second is uniform shear flow over a semi-infinite plate, and the third is the flow induced by a power-law stretching surface. In the first two cases, the effect of streamwise plate motion is taken into account by the parameter λ. In each case, the similarity solutions reduce the governing boundary layer equations to a primary ordinary differential equation for the streamwise flow and a secondary linear equation coupled to the primary solution for the cross flow. It is found that an infinity of solutions exist in each problem and the unique solution in each case is found by applying the Glauert criterion. In some instances, a simple exact solution for the cross flow is presented. Results for the wall shear stresses and velocity profiles are given in graphical form.

  17. Design, tolerancing and alignment of pushbroom imaging spectrometers for high response uniformity

    NASA Technical Reports Server (NTRS)

    Mouroulis, P.; Shea, J.; Thomas, D.

    2001-01-01

    We present a design and tolerancing approach that permits the achievement of a high degree of spatial and spectral uniformity of response from a pushbroom imaging spectrometer. Such uniformity of response is crucial for the extraction of accurate spectroscopic information from remotely sensed data. The spectrometer system example comprises two independent spectrometer modules covering the 400-2500 nm range, seperated through a dichroic mirror.

  18. Growing Uniform Graphene Disks and Films on Molten Glass for Heating Devices and Cell Culture.

    PubMed

    Chen, Yubin; Sun, Jingyu; Gao, Junfeng; Du, Feng; Han, Qi; Nie, Yufeng; Chen, Zhaolong; Bachmatiuk, Alicja; Priydarshi, Manish Kr; Ma, Donglin; Song, Xiuju; Wu, Xiaosong; Xiong, Chunyang; Rümmeli, Mark H; Ding, Feng; Zhang, Yanfeng; Liu, Zhongfan

    2015-12-16

    The direct growth of uniform graphene disks and their continuous film is achieved by exploiting the molten state of glass. The use of molten glass enables highly uniform nucleation and an enhanced growth rate (tenfold) of graphene, as compared to those scenarios on commonly used insulating solids. The obtained graphene glasses show promising application potentials in daily-life scenarios such as smart heating devices and biocompatible cell-culture mediums.

  19. Regulation of the Deposition Morphology of Inkjet-Printed Crystalline Materials via Polydopamine Functional Coatings for Highly Uniform and Electrically Conductive Patterns.

    PubMed

    Liu, Liang; Ma, Siyuan; Pei, Yunheng; Xiong, Xiao; Sivakumar, Preeth; Singler, Timothy J

    2016-08-24

    We report a method to achieve highly uniform inkjet-printed silver nitrate (AgNO3) and a reactive silver precursor patterns on rigid and flexible substrates functionalized with polydopamine (PDA) coatings. The printed AgNO3 patterns on PDA-coated substrates (glass and polyethylene terephthalate (PET)) exhibit a narrow thickness distribution ranging between 0.9 and 1 μm in the line transverse direction and uniform deposition profiles in the line axial direction. The deposited reactive silver precursor patterns on PDA-functionalized substrates also show "dome-shaped" morphology without "edge-thickened" structure due to "coffee-stain" effect. We posit that the highly uniform functional ink deposits formed on PDA-coated substrates are attributable to the strong binding interaction between the abundant catecholamine moieties at the PDA surface and the metallic silver cations (Ag(+) or Ag(NH3)(2+)) in the solutal inks. During printing of the ink rivulet and solvent evaporation, the substrate-liquid ink (S-L) interface is enriched with the silver-based cations and a solidification at the S/L interface is induced. The preferential solidification initiated at the S-L interface is further verified by the in situ visualization of the dynamic solidification process during solvent evaporation, and results suggest an enhanced crystal nucleation and growth localized at the S-L interface on PDA functionalized substrates. This interfacial interaction mediates solute transport in the liquid phase, resulting in the controlled enrichment of solute at the S-L interface and mitigated solute precipitation in both the contact line region and the liquid ink-vapor (L-V) interface due to evaporation. This mediated transport contributes to the final uniform solid deposition for both types of ink systems. This technique provides a complementary strategy for achieving highly uniform inkjet-printed crystalline structures, and can serve as an innovative foundation for high-precision additive

  20. Impact of Uniform Methods on Interlaboratory Antibody Titration Variability: Antibody Titration and Uniform Methods.

    PubMed

    Bachegowda, Lohith S; Cheng, Yan H; Long, Thomas; Shaz, Beth H

    2017-01-01

    -Substantial variability between different antibody titration methods prompted development and introduction of uniform methods in 2008. -To determine whether uniform methods consistently decrease interlaboratory variation in proficiency testing. -Proficiency testing data for antibody titration between 2009 and 2013 were obtained from the College of American Pathologists. Each laboratory was supplied plasma and red cells to determine anti-A and anti-D antibody titers by their standard method: gel or tube by uniform or other methods at different testing phases (immediate spin and/or room temperature [anti-A], and/or anti-human globulin [AHG: anti-A and anti-D]) with different additives. Interlaboratory variations were compared by analyzing the distribution of titer results by method and phase. -A median of 574 and 1100 responses were reported for anti-A and anti-D antibody titers, respectively, during a 5-year period. The 3 most frequent (median) methods performed for anti-A antibody were uniform tube room temperature (147.5; range, 119-159), uniform tube AHG (143.5; range, 134-150), and other tube AHG (97; range, 82-116); for anti-D antibody, the methods were other tube (451; range, 431-465), uniform tube (404; range, 382-462), and uniform gel (137; range, 121-153). Of the larger reported methods, uniform gel AHG phase for anti-A and anti-D antibodies had the most participants with the same result (mode). For anti-A antibody, 0 of 8 (uniform versus other tube room temperature) and 1 of 8 (uniform versus other tube AHG), and for anti-D antibody, 0 of 8 (uniform versus other tube) and 0 of 8 (uniform versus other gel) proficiency tests showed significant titer variability reduction. -Uniform methods harmonize laboratory techniques but rarely reduce interlaboratory titer variance in comparison with other methods.

  1. Luminance uniformity study of OLED lighting panels depending on OLED device structures.

    PubMed

    Bae, Hyeong Woo; Son, Young Hoon; Kang, Byoung Yeop; Lee, Jung Min; Nam, Hyoungsik; Kwon, Jang Hyuk

    2015-11-30

    This paper describes the luminance uniformity of OLED lighting panels depending on OLED device structures of single emission layer (single-EML), 2-tandem, and 3-tandem. The luminance distribution is evaluated through the circuit simulation and the fabricated panel measurement. In the simulation results with yellow-green color panels of 30 × 80 mm2 emission area, a 3-tandem structure shows the lowest non-uniformity (1.34% at 7.5V), compared to single-EML (5.67% at 2.8V) and 2-tandem (2.78% at 5.3 V) structures at 1,000 cd/m2. The luminance non-uniformity is germane to the OLED conductance showing that the high luminance-current efficiency is of the most importance to achieve the uniform voltage and luminance distribution. In measurement, a 3-tandem structure also achieves the most uniform luminance distribution with non-uniformity of 4.1% while single EML and 2-tandem structures accomplish 9.6%, and 6.4%, respectively, at ~1,000 cd/m2. In addition, the simulation results ensure that a 3-tandem structure panel is allowed to be enlarged the panel size up to about 5,000 mm2 for lower luminance non-uniformity than 10% without any auxiliary metal electrodes.

  2. Uniform pump scheme for a LD face-pumped Nd:YAG slab amplifier

    NASA Astrophysics Data System (ADS)

    Jia, Dan; Fan, Zhongwei; Chen, Yanzhong; Guo, Guangyan; He, Jianguo; Zhao, Tianzhuo

    2016-10-01

    A new pump-shaping scheme for a LD face-pumped Nd:YAG slab laser amplifier is proposed, aiming to achieve uniform pump distributions. Plano-concave cylindrical mirror arrays are used to homogenize the pump distributions in the LD slow axes, and meanwhile optical-waveguide structures are used for the LD fast axes. Simulations based on ray tracing method indicate that the scheme effectively realizes uniform pump intensity distributions. The fluorescence distributions and small signal gains at different locations both verify the pump uniformity reaches higher than 90%.

  3. Design of a modified uniform redundant-array mask for portable gamma cameras.

    PubMed

    Olmos, P; Cid, C; Bru, A; Oller, J C; de Pablos, J L; Perez, J M

    1992-08-10

    Uniform redundant-array masks have been reported as good lenses to form the image of gamma sources, with the correlation between the mask-aperture matrix and the shadows projected on a static position-sensitive detector. We present a modified uniform redundant-array configuration suitable for portable and small-size gamma cameras; its ability to reconstruct the image of several sources is analyzed. We have carried out a Montecarlo simulation of the gamma interactions in the mask, defining the expected response of the correlation process and comparing it with that achieved with the usual uniform redundant-array configurations.

  4. Towards uniformly dispersed battery electrode composite materials: Characteristics and performance

    SciTech Connect

    Yo Han Kwon; Takeuchi, Esther S.; Huie, Matthew M.; Choi, Dalsu; Chang, Mincheol; Marschilok, Amy C.; Takeuchi, Kenneth J.; Reichmanis, Elsa

    2016-01-14

    Battery electrodes are complex mesoscale systems comprised of electroactive components, conductive additives, and binders. In this report, methods for processing electrodes with dispersion of the components are described. To investigate the degree of material dispersion, a spin-coating technique was adopted to provide a thin, uniform layer that enabled observation of the morphology. Distinct differences in the distribution profile of the electrode components arising from individual materials physical affinities were readily identified. Hansen solubility parameter (HSP) analysis revealed pertinent surface interactions associated with materials dispersivity. Further studies demonstrated that HSPs can provide an effective strategy to identify surface modification approaches for improved dispersions of battery electrode materials. Specifically, introduction of surfactantlike functionality such as oleic acid (OA) capping and P3HT-conjugated polymer wrapping on the surface of nanomaterials significantly enhanced material dispersity over the composite electrode. The approach to the surface treatment on the basis of HSP study can facilitate design of composite electrodes with uniformly dispersed morphology and may contribute to enhancing their electrical and electrochemical behaviors. The conductivity of the composites and their electrochemical performance was also characterized. In conclusion, the study illustrates the importance of considering electronic conductivity, electron transfer, and ion transport in the design of environments incorporating active nanomaterials.

  5. Towards uniformly dispersed battery electrode composite materials: Characteristics and performance

    DOE PAGES

    Yo Han Kwon; Takeuchi, Esther S.; Huie, Matthew M.; ...

    2016-01-14

    Battery electrodes are complex mesoscale systems comprised of electroactive components, conductive additives, and binders. In this report, methods for processing electrodes with dispersion of the components are described. To investigate the degree of material dispersion, a spin-coating technique was adopted to provide a thin, uniform layer that enabled observation of the morphology. Distinct differences in the distribution profile of the electrode components arising from individual materials physical affinities were readily identified. Hansen solubility parameter (HSP) analysis revealed pertinent surface interactions associated with materials dispersivity. Further studies demonstrated that HSPs can provide an effective strategy to identify surface modification approaches formore » improved dispersions of battery electrode materials. Specifically, introduction of surfactantlike functionality such as oleic acid (OA) capping and P3HT-conjugated polymer wrapping on the surface of nanomaterials significantly enhanced material dispersity over the composite electrode. The approach to the surface treatment on the basis of HSP study can facilitate design of composite electrodes with uniformly dispersed morphology and may contribute to enhancing their electrical and electrochemical behaviors. The conductivity of the composites and their electrochemical performance was also characterized. In conclusion, the study illustrates the importance of considering electronic conductivity, electron transfer, and ion transport in the design of environments incorporating active nanomaterials.« less

  6. Toward Uniformly Dispersed Battery Electrode Composite Materials: Characteristics and Performance.

    PubMed

    Kwon, Yo Han; Huie, Matthew M; Choi, Dalsu; Chang, Mincheol; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S; Reichmanis, Elsa

    2016-02-10

    Battery electrodes are complex mesoscale systems comprised of electroactive components, conductive additives, and binders. In this report, methods for processing electrodes with dispersion of the components are described. To investigate the degree of material dispersion, a spin-coating technique was adopted to provide a thin, uniform layer that enabled observation of the morphology. Distinct differences in the distribution profile of the electrode components arising from individual materials physical affinities were readily identified. Hansen solubility parameter (HSP) analysis revealed pertinent surface interactions associated with materials dispersivity. Further studies demonstrated that HSPs can provide an effective strategy to identify surface modification approaches for improved dispersions of battery electrode materials. Specifically, introduction of surfactantlike functionality such as oleic acid (OA) capping and P3HT-conjugated polymer wrapping on the surface of nanomaterials significantly enhanced material dispersity over the composite electrode. The approach to the surface treatment on the basis of HSP study can facilitate design of composite electrodes with uniformly dispersed morphology and may contribute to enhancing their electrical and electrochemical behaviors. The conductivity of the composites and their electrochemical performance was also characterized. The study illustrates the importance of considering electronic conductivity, electron transfer, and ion transport in the design of environments incorporating active nanomaterials.

  7. Energy efficient LED layout optimization for near-uniform illumination

    NASA Astrophysics Data System (ADS)

    Ali, Ramy E.; Elgala, Hany

    2016-09-01

    In this paper, we consider the problem of designing energy efficient light emitting diodes (LEDs) layout while satisfying the illumination constraints. Towards this objective, we present a simple approach to the illumination design problem based on the concept of the virtual LED. We formulate a constrained optimization problem for minimizing the power consumption while maintaining a near-uniform illumination throughout the room. By solving the resulting constrained linear program, we obtain the number of required LEDs and the optimal output luminous intensities that achieve the desired illumination constraints.

  8. Uniform circular array for structural health monitoring of composite structures

    NASA Astrophysics Data System (ADS)

    Stepinski, Tadeusz; Engholm, Marcus

    2008-03-01

    Phased array with all-azimuth angle coverage would be extremely useful in structural health monitoring (SHM) of planar structures. One method to achieve the 360° coverage is to use uniform circular arrays (UCAs). In this paper we present the concept of UCA adapted for SHM applications. We start from a brief presentation of UCA beamformers based on the principle of phase mode excitation. UCA performance is illustrated by the results of beamformer simulations performed for the narrowband and wideband ultrasonic signals. Preliminary experimental results obtained with UCA used for the reception of ultrasonic signals propagating in an aluminum plate are also presented.

  9. A novel polyimide based micro heater with high temperature uniformity

    DOE PAGES

    Yu, Shifeng; Wang, Shuyu; Lu, Ming; ...

    2017-02-06

    MEMS based micro heaters are a key component in micro bio-calorimetry, nondispersive infrared gas sensors, semiconductor gas sensors and microfluidic actuators. A micro heater with a uniform temperature distribution in the heating area and short response time is desirable in ultrasensitive temperature-dependent measurements. In this study, we propose a novel micro heater design to reach a uniform temperature in a large heating area by optimizing the heating power density distribution in the heating area. A polyimide membrane is utilized as the substrate to reduce the thermal mass and heat loss which allows for fast thermal response as well as amore » simplified fabrication process. A gold and titanium heating element is fabricated on the flexible polyimide substrate using the standard MEMS technique. The temperature distribution in the heating area for a certain power input is measured by an IR camera, and is consistent with FEA simulation results. Finally, this design can achieve fast response and uniform temperature distribution, which is quite suitable for the programmable heating such as impulse and step driving.« less

  10. Uniformity of stratum-ventilated thermal environment and thermal sensation.

    PubMed

    Cheng, Y; Fong, M L; Yao, T; Lin, Z; Fong, K F

    2014-10-01

    Three human test series were conducted to evaluate the uniformity of the thermal environments in a stratum-ventilated chamber with dimensions of 8.8 m (L) × 5.1 m (W) × 2.4 m (H). In all, nineteen conditions were generated by adjusting the room temperature, supply airflow rate, and supply terminal type. An air diffuser performance index (ADPI) of at least 80% was achieved for most cases. This result shows that the air velocity and temperature in the occupied zone are reasonably uniform. Subjective assessments using the ASHRAE 7-point scale indicate that the thermal sensations of the subjects in stratum ventilation are also uniform. This study examines the applicability of the predicted mean vote (PMV) model for evaluating stratum ventilation. When compared to the actual mean thermal sensation votes (ATS), the PMV values are acceptable. The PMV results at a height of 1.1 m above the floor show better agreement with the ATS than at a height of 0.1 m.

  11. Uniform Sampling for Directed P2P Networks

    NASA Astrophysics Data System (ADS)

    Hall, Cyrus; Carzaniga, Antonio

    Selecting a random peer with uniform probability across a peer-to-peer (P2P) network is a fundamental function for unstructured search, data replication, and monitoring algorithms. Such uniform sampling is supported by several techniques. However, current techniques suffer from sample bias and limited applicability. In this paper, we present a sampling algorithm that achieves a desired uniformity while making essentially no assumptions about the underlying P2P network. This algorithm, called doubly stochastic converge (DSC), iteratively adjusts the probabilities of crossing each link in the network during a random walk, such that the resulting transition matrix is doubly stochastic. DSC is fully decentralized and is designed to work on both directed and undirected topologies, making it suitable for virtually any P2P network. Our simulations show that DSC converges quickly on a wide variety of topologies, and that the random walks needed for sampling are short for most topologies. In simulation studies with FreePastry, we show that DSC is resilient to high levels of churn, while incurring a minimal sample bias.

  12. Ultra-low noise and exceptional uniformity of SensL C-series SiPM sensors

    NASA Astrophysics Data System (ADS)

    Jackson, C.; Wall, L.; O'Neill, K.; McGarvey, B.; Herbert, D.

    2015-03-01

    SensL C-Series Silicon Photomultiplier (SiPM) sensors are fabricated in a high-volume CMOS foundry to a custom SensL process, and packaged as a reflow solderable surface mount device. Advances in SiPM production have resulted in significant improvement in PDE, dark current as well as tighter breakdown voltage uniformity for the C-Series SiPM sensors. The SiPM are fabricated with a shallow P-on-N junction optimized for the detection of shorter wavelength photons, with a peak PDE of 41% at 420nm and excellent sensitivity extending to wavelengths <300nm. The dark currents have been reduced through the reduction of damage during semiconductor processing and an order of magnitude reduction has been achieved. The breakdown voltage variation has been improved through process optimization to minimize variations. With these process improvements typical dark count rates of ~30kHz/mm2 are achieved simultaneously with breakdown voltage uniformity of ±213mV demonstrated. In addition, application specific measurements of CRT (Coincidence Resolving Time) that are relevant to PET (positron emission tomography) will be shown to be 210ps at 7.5V overvoltage. In addition to device characterization work, this paper will address the wafer-level fabrication and testing, package level testing required by high volume SiPM sensor applications.

  13. Uniform color space based on color matching

    NASA Astrophysics Data System (ADS)

    Liao, Shih-Fang; Yang, Tsung-Hsun; Lee, Cheng-Chung

    2007-09-01

    This research intends to explore with a uniform color space based on the CIE 1931 x-y chromatic coordinate system. The goal is to improve the non-uniformity of the CIE 1931 x-y chromaticity diagram such as to approach the human color sensation as possible; however, its simple methodology still can be kept. In spite of the existence of various kinds of the uniform color coordinate systems built up early (CIE u'-v', CIE Lab, CIE LUV, etc.), the establishment of a genuine uniform color space is actually still an important work both for the basic research in color science and the practical applications of colorimetry, especially for recent growing request in illumination engineering and in display technology. In this study, the MacAdam ellipses and the Munsell color chips are utilized for the comparison with the human color sensation. One specific linear transformation matrix is found for the CIE 1931 color matching functions (see manuscript) to become the novel uniform ones. With the aid of the optimization method, the transformation matrix can be easily discovered and makes the 25 MacAdam ellipses are similar to each other in the novel uniform color space. On the other hand, the perfectiveness of the equal-hue curves and the equal-chroma contours from the Mnusell color chips evaluates for the best optimization conditions among several different definitions for the similarity of all the MacAdam ellipses. Finally, the color difference between any two colors can be simply measured by the Euclidean distance in the novel uniform color space and is still fitted to the human color sensation.

  14. Graded Achievement, Tested Achievement, and Validity

    ERIC Educational Resources Information Center

    Brookhart, Susan M.

    2015-01-01

    Twenty-eight studies of grades, over a century, were reviewed using the argument-based approach to validity suggested by Kane as a theoretical framework. The review draws conclusions about the meaning of graded achievement, its relation to tested achievement, and changes in the construct of graded achievement over time. "Graded…

  15. The segmented non-uniform dielectric module design for uniformity control of plasma profile in a capacitively coupled plasma chamber

    SciTech Connect

    Xia, Huanxiong Xiang, Dong Yang, Wang Mou, Peng

    2014-12-15

    Low-temperature plasma technique is one of the critical techniques in IC manufacturing process, such as etching and thin-film deposition, and the uniformity greatly impacts the process quality, so the design for the plasma uniformity control is very important but difficult. It is hard to finely and flexibly regulate the spatial distribution of the plasma in the chamber via controlling the discharge parameters or modifying the structure in zero-dimensional space, and it just can adjust the overall level of the process factors. In the view of this problem, a segmented non-uniform dielectric module design solution is proposed for the regulation of the plasma profile in a CCP chamber. The solution achieves refined and flexible regulation of the plasma profile in the radial direction via configuring the relative permittivity and the width of each segment. In order to solve this design problem, a novel simulation-based auto-design approach is proposed, which can automatically design the positional sequence with multi independent variables to make the output target profile in the parameterized simulation model approximate the one that users preset. This approach employs an idea of quasi-closed-loop control system, and works in an iterative mode. It starts from initial values of the design variable sequences, and predicts better sequences via the feedback of the profile error between the output target profile and the expected one. It never stops until the profile error is narrowed in the preset tolerance.

  16. The segmented non-uniform dielectric module design for uniformity control of plasma profile in a capacitively coupled plasma chamber

    NASA Astrophysics Data System (ADS)

    Xia, Huanxiong; Xiang, Dong; Yang, Wang; Mou, Peng

    2014-12-01

    Low-temperature plasma technique is one of the critical techniques in IC manufacturing process, such as etching and thin-film deposition, and the uniformity greatly impacts the process quality, so the design for the plasma uniformity control is very important but difficult. It is hard to finely and flexibly regulate the spatial distribution of the plasma in the chamber via controlling the discharge parameters or modifying the structure in zero-dimensional space, and it just can adjust the overall level of the process factors. In the view of this problem, a segmented non-uniform dielectric module design solution is proposed for the regulation of the plasma profile in a CCP chamber. The solution achieves refined and flexible regulation of the plasma profile in the radial direction via configuring the relative permittivity and the width of each segment. In order to solve this design problem, a novel simulation-based auto-design approach is proposed, which can automatically design the positional sequence with multi independent variables to make the output target profile in the parameterized simulation model approximate the one that users preset. This approach employs an idea of quasi-closed-loop control system, and works in an iterative mode. It starts from initial values of the design variable sequences, and predicts better sequences via the feedback of the profile error between the output target profile and the expected one. It never stops until the profile error is narrowed in the preset tolerance.

  17. Method for forming a uniformly dense polymer foam body

    DOEpatents

    Whinnery, Jr., Leroy

    2002-01-01

    A method for providing a uniformly dense polymer foam body having a density between about 0.013 .sup.g /.sub.cm.sup..sub.3 to about 0.5 .sup.g /.sub.cm.sup..sub.3 is disclosed. The method utilizes a thermally expandable polymer microballoon material wherein some of the microballoons are unexpanded and some are only partially expanded. It is shown that by mixing the two types of materials in appropriate ratios to achieve the desired bulk final density, filling a mold with this mixture so as to displace all or essentially all of the internal volume of the mold, heating the mold for a predetermined interval at a temperature above about 130.degree. C., and then cooling the mold to a temperature below 80.degree. C. the molded part achieves a bulk density which varies by less then about .+-.6% everywhere throughout the part volume.

  18. Uniform gold nanoarray formed by controlled IP6 micelles for chemical mapping

    NASA Astrophysics Data System (ADS)

    Chen, Xiyao; Wen, Ying; Wang, Na; Gu, Kai; Yang, Haifeng

    2011-05-01

    A uniform Au nanoarray is successfully formed at an indium tin oxide (ITO) glass surface modified with well-distributed inositol hexakisphosphoric (IP6) micelle layers by controlling the pH of the medium at 10. When Rhodamine 6G (R6G) and 2-mercaptopyridine (2-MPy) are used as the Raman probes, the uniform Au nanoarray presents a sound surface enhanced Raman scattering (SERS) efficiency and a reproducible Raman signal in two dimensions. The relative standard deviation (RSD) of Raman intensities of R6G or 2-MPy on the uniform Au nanoarray recorded by point to point is less than 12%, which is beneficial to its application for chemical mapping or imaging. A case of Raman point-mapping for onion epidermis is demonstrated in the present work. A uniform IP6-Au nanoarray might be mass-produced by this protocol.

  19. Uniform gold nanoarray formed by controlled IP6 micelles for chemical mapping.

    PubMed

    Chen, Xiyao; Wen, Ying; Wang, Na; Gu, Kai; Yang, Haifeng

    2011-05-20

    A uniform Au nanoarray is successfully formed at an indium tin oxide (ITO) glass surface modified with well-distributed inositol hexakisphosphoric (IP(6)) micelle layers by controlling the pH of the medium at 10. When Rhodamine 6G (R6G) and 2-mercaptopyridine (2-MPy) are used as the Raman probes, the uniform Au nanoarray presents a sound surface enhanced Raman scattering (SERS) efficiency and a reproducible Raman signal in two dimensions. The relative standard deviation (RSD) of Raman intensities of R6G or 2-MPy on the uniform Au nanoarray recorded by point to point is less than 12%, which is beneficial to its application for chemical mapping or imaging. A case of Raman point-mapping for onion epidermis is demonstrated in the present work. A uniform IP(6)-Au nanoarray might be mass-produced by this protocol.

  20. Uniform colloidal zinc compounds of various morphologies

    SciTech Connect

    Castellano, M.; Matijevic, E. )

    1989-02-01

    The preparation of finely dispersed zinc compounds consisting of uniform particles is described. Aging at elevated temperatures ({approx} 90{degree}C) of aqueous solutions of zinc nitrate or zinc chloride in the presence of urea resulted in precipitation of uniform rodlike basic zinc carbonate particles. These solids show x-ray characteristics of crystalline hydrozincite. In the presence of sulfate ions amorphous spherical particles of narrow size distribution of the same chemical composition are generated. On calcination both kinds of solids change to zinc oxide yet retain the original shape. In the presence of NaH{sub 2}PO{sub 4} and urea, aqueous zinc salt solutions on aging yield rather uniform amorphous spherical zinc basic phosphate particles, which on calcination lose water.

  1. Nonspherical LED packaging lens for uniformity improvement

    NASA Astrophysics Data System (ADS)

    Chang, Yu-Cheng; Ou, Chung-Jen; Tsai, Yu-Sheng; Juang, Fuh-Shyang

    2009-05-01

    Light emitting diode (LED) has more advantages compared with a traditional incandescent light bulb and a fluorescent lamp, such as small size, low quantity of heat, long life, low power consumption, fast response, plain packaging and ease of develop ment of a frivolous short product. A methodology is proposed to improve the uniformity of the LED illumination system. As a light source in a backlight unit (BLU), the requirement for optical characteristics of a LED is different from highly directional conventional ones. New diffused-type LEDs need to be developed to fulfill the requirement of the BLU industry. A non-spherical lens is designed to optimize uniformity, and a great improvement in uniformity from 28.4 to 64% is demonstrated. In the future, it may used in an LED display to improve the unevenness of illumination.

  2. Research on highly uniform laser illumination system

    NASA Astrophysics Data System (ADS)

    Zhao, Huifu

    2016-10-01

    A new laser illumination system was designed based on the analysis of regular homogenization technology. It was widely used in the field of security without sunlight and other lighting. The new laser illumination system used eccentric motor to drive a light shaping scatterer to vibrate at a frequency that faster than the electronic shutter of cameras, making multiple light superimposed in integration time to form a uniform illumination effect. The laser illumination system can eliminate interference fringes and laser speckles, and realize the purpose of homogenization illumination. Experimental results show that the new laser illumination system makes the energy efficiency reach up to 90% and the illumination uniformity reach up to 94% in the effective area. The new laser illumination system improves the uniformity of illumination and utilization rate of laser energy, thus improves the image quality of the illuminated target.

  3. Uniform distortion of a heated turbulent wake

    NASA Technical Reports Server (NTRS)

    Kawall, J. G.; Keffer, J. F.

    1978-01-01

    Digital sampling and processing techniques are used to assess the effect of a uniform and constant strain rate on a slightly heated cylinder-generated wake which had undergone a prestrain development distance of 115 cylinder diameters. The wake is generated by a circular heating element (6.6-mm-diam cylinder) mounted horizontally in the center of a low-speed open return wind tunnel. The strain field is produced by a distortion duct oriented in such a way as to accentuate any periodic interface structure which might be present in the undistorted wake. Interface statistics are presented for both the undistorted (near) wake and the uniformly strained wake, and conditional (point) averages of the streamwise velocity and passive temperature fields of the strained wake. The results suggest that the interface thickness is fairly uniform along the back but decreases along the front with distance from the wake center.

  4. Elastic stability of non-uniform columns

    NASA Astrophysics Data System (ADS)

    Lee, S. Y.; Kuo, Y. H.

    1991-07-01

    A simple and efficient method is proposed to investigate the elastic stability of three different tapered columns subjected to uniformly distributed follower forces. The influences of the boundary conditions and taper ratio on critical buckling loads are investigated. The critical buckling loads of columns of rectangular cross section with constant depth and linearly varied width ( T1), constant width and linearly varied depth ( T2) and double taper ( T3) are investigated. Among the three different non-uniform columns considered, taper ratio has the greatest influence on the critical buckling load of column T3 and the lowest influence on that of column T1. The types of instability mechanisms for hinged-hinged and cantilever non-uniform columns are divergence and flutter respectively. However, for clamped-hinged and clamped-clamped non-uniform columns, the type of instability mechanism for column T1 is divergence, while that for columns T2 and T3 is divergence only when the taper ratio of the columns is greater than certain critical values and flutter for the rest value of taper ratio. When the type of instability mechanism changes from divergence to flutter, there is a finite jump for the critical buckling load. The influence of taper ratio on the elastic stability of cantilever column T3 is very sensitive for small values of the taper ratio and there also exist some discontinieties in the critical buckling loads of flutter instability. For a hinged-hinged non-uniform column ( T2 or T3) with a rotational spring at the left end of the column, when the taper ratio is less than the critical value the instability mechanism changes from divergence to flutter as the rotational spring constant is increased. For a clamped-elastically supported non-uniform column, when the taper ratio is greater than the critical value the instability mechanism changes from flutter to divergence as the translational spring constant is increased.

  5. Uniform attractors for non-autonomous random dynamical systems

    NASA Astrophysics Data System (ADS)

    Cui, Hongyong; Langa, José A.

    2017-07-01

    This paper is devoted to establishing a (random) uniform attractor theory for non-autonomous random dynamical systems (NRDS). The uniform attractor is defined as the minimal compact uniformly pullback attracting random set. Nevertheless, the uniform pullback attraction in fact implies a uniform forward attraction in probability, and implies also an almost uniform pullback attraction for discrete time-sequences. Though no invariance is required by definition, the uniform attractor can have a negative semi-invariance under certain conditions. Several existence criteria for uniform attractors are given, and the relationship between uniform and cocycle attractors is carefully studied. To overcome the measurability difficulty, the symbol space is required to be Polish which is shown fulfilled by the hulls of Llocp (R ;Lr) functions, p , r > 1. Moreover, uniform attractors for continuous NRDS are shown determined by uniformly attracting deterministic compact sets. Finally, the uniform attractor for a stochastic reaction-diffusion equation with translation-bounded external forcing are studied as applications.

  6. Uniform diffracted fields from a perfectly conducting cylindrical reflector with modified theory of physical optics.

    PubMed

    Yalçın, Uğur; Sarnık, Mücahit

    2013-01-01

    The uniform diffracted fields are calculated on PEC cylindrical reflector by Modified Theory of Physical Optics (MTPO). It is aimed to convert the noncontinuous solution to a continuous solution by finding a uniform equation which does not contain any expression converging to 0 in the denominator part. Three axioms of MTPO theory are used to construct the integral equations for the perfectly electrically conducting surface application. The "edge-point" technique is used to find the diffracted field, and uniform solution is to be found via "detour parameter(s)." Finally, the obtained results are to be compared with the nonuniform ones, numerically.

  7. Uniform Diffracted Fields from a Perfectly Conducting Cylindrical Reflector with Modified Theory of Physical Optics

    PubMed Central

    Yalçın, Uğur; Sarnık, Mücahit

    2013-01-01

    The uniform diffracted fields are calculated on PEC cylindrical reflector by Modified Theory of Physical Optics (MTPO). It is aimed to convert the noncontinuous solution to a continuous solution by finding a uniform equation which does not contain any expression converging to 0 in the denominator part. Three axioms of MTPO theory are used to construct the integral equations for the perfectly electrically conducting surface application. The “edge-point” technique is used to find the diffracted field, and uniform solution is to be found via “detour parameter(s).” Finally, the obtained results are to be compared with the nonuniform ones, numerically. PMID:23766679

  8. Preparation and characterization of uniform drug particles: dehydrocholic acid.

    PubMed

    Mohamed, Amr Ali; Matijević, Egon

    2012-02-15

    Two methods for the preparation of uniform dispersions of dehydrocholic acid of different morphologies are described. In the first case, the drug was dissolved in acetone and then re-precipitated by adding a non-solvent (either water or an aqueous stabilizer solution), which yielded rod-like particles. In the second procedure, spheres, consisting of small elongated subunits, were obtained by acidification of basic aqueous solutions of the drug. The resulting particles were characterized in terms of their structure and surface charge characteristics.

  9. Non-uniform impact excitation of a cylindrical bar

    NASA Astrophysics Data System (ADS)

    Karp, Baruch; Dorogoy, Avraham; Wang, Zonggang

    2009-06-01

    An experimental and numerical study of a non-uniform impact excitation of a circular bar is reported. In experiments, nine strikers with different contact area were accelerated against a circular bar. Axial surface strain of the impacted bar was measured at several distances from the impinged end to include the near and the far fields. The same experimental conditions were solved numerically using a commercial finite element code. It was demonstrated that the far-field response is insensitive to both the size and the form of the striker's colliding end. The distance at which such insensitivity is set is estimated to be approximately one and a half bar diameters.

  10. Micro-gravity: current distributions creating a uniform force field

    NASA Astrophysics Data System (ADS)

    Vincent-Viry, O.; Mailfert, A.; Colteu, A.; Dael, A.; Gourdin, C.; Quettier, L.

    2001-02-01

    This paper presents two structures of superconducting coils able to give satisfactory solutions to the problem of generation of uniform field of high magnetic forces. The first structure is modeled by the use of purely surface current densities, whereas the second one can be described with volume current densities. Both of these structures proceed from the study of a particular expression of the complex magnetic potential introduced for structures with two-dimensional geometry. This work is carried out in a research collaboration between the GREEN and the DSM-DAPNIA department of the CEA Saclay.

  11. Uniform color space is not homogeneous

    NASA Astrophysics Data System (ADS)

    Kuehni, Rolf G.

    2002-06-01

    Historical data of chroma scaling and hue scaling are compared and evidence is shown that we do not have a reliable basis in either case. Several data sets indicate explicitly or implicitly that the number of constant sized hue differences between unique hues as well as in the quadrants of the a*, b* diagram differs making what is commonly regarded as uniform color space inhomogeneous. This problem is also shown to affect the OSA-UCS space. A Euclidean uniform psychological or psychophysical color space appears to be impossible.

  12. The electrostatic eigenmodes of a cold plasma with a two-dimensional density non-uniformity

    NASA Astrophysics Data System (ADS)

    Naslund, E.; Gradov, O. M.

    1985-10-01

    A new kind of surface oscillation, which can exist when the usual surface waves are absent because of resonant absorption, has been studied for a non-uniform plasma slab. Special attention is paid to the influence of the boundaries on the eigenfrequency spectrum.

  13. Gliding Motility of Mycoplasma mobile on Uniform Oligosaccharides

    PubMed Central

    Kasai, Taishi; Hamaguchi, Tasuku

    2015-01-01

    ABSTRACT The binding and gliding of Mycoplasma mobile on a plastic plate covered by 53 uniform oligosaccharides were analyzed. Mycoplasmas bound to and glided on only 21 of the fixed sialylated oligosaccharides (SOs), showing that sialic acid is essential as the binding target. The affinities were mostly consistent with our previous results on the inhibitory effects of free SOs and suggested that M. mobile recognizes SOs from the nonreducing end with four continuous sites as follows. (i and ii) A sialic acid at the nonreducing end is tightly recognized by tandemly connected two sites. (iii) The third site is recognized by a loose groove that may be affected by branches. (iv) The fourth site is recognized by a large groove that may be enhanced by branches, especially those with a negative charge. The cells glided on uniform SOs in manners apparently similar to those of the gliding on mixed SOs. The gliding speed was related inversely to the mycoplasma's affinity for SO, suggesting that the detaching step may be one of the speed determinants. The cells glided faster and with smaller fluctuations on the uniform SOs than on the mixtures, suggesting that the drag caused by the variation in SOs influences gliding behaviors. IMPORTANCE Mycoplasma is a group of bacteria generally parasitic to animals and plants. Some Mycoplasma species form a protrusion at a pole, bind to solid surfaces, and glide in the direction of the protrusion. These procedures are essential for parasitism. Usually, mycoplasmas glide on mixed sialylated oligosaccharides (SOs) derived from glycoprotein and glycolipid. Since gliding motility on uniform oligosaccharides has never been observed, this study gives critical information about recognition and interaction between receptors and SOs. PMID:26148712

  14. An interface-directed coassembly approach to synthesize uniform large-pore mesoporous silica spheres.

    PubMed

    Wang, Minghong; Sun, Zhenkun; Yue, Qin; Yang, Jie; Wang, Xiqing; Deng, Yonghui; Yu, Chengzhong; Zhao, Dongyuan

    2014-02-05

    A facile and controllable interface-directed coassembly (IDCA) approach is developed for the first time to synthesize uniform discrete mesoporous silica particles with a large pore size (ca. 8 nm) by using 3-dimensional macroporous carbon (3DOMC) as the nanoreactor for the confined coassembly of template molecules and silica source. By controlling the amount of the precursor solution and using Pluronic templates with different compositions, we can synthesize mesoporous silica particles with diverse morphologies (spheres, hollow spheres, and hemispheres) and different mesostructure (e.g., 2-D hexagonal and 3D face centered cubic symmetry), high surface area of about 790 m(2)/g, and large pore volume (0.98 cm(3)/g). The particle size can be tunable from submicrometer to micrometer regimes by changing the macropore diameter of 3DOMC. Importantly, this synthesis concept can be extended to fabricate multifunctional mesoporous composite spheres with a magnetic core and a mesoporous silica shell, large saturated magnetization (23.5 emu/g), and high surface area (280 m(2)/g). With the use of the magnetic mesoporous silica spheres as a magnetically recyclable absorbent, a fast and efficient removal of microcystin from water is achieved, and they can be recycled for 10 times without a significant decrease of removal efficiency for microcystin.

  15. Comparison of two leading uniform theories of edge diffraction with the exact uniform asymptotic solution

    NASA Technical Reports Server (NTRS)

    Boersma, J.; Rahmat-Samii, Y.

    1980-01-01

    The diffraction of an arbitrary cylindrical wave by a half-plane has been treated by Rahmat-Samii and Mittra who used a spectral domain approach. In this paper, their exact solution for the total field is expressed in terms of a new integral representation. For large wave number k, two rigorous procedures are described for the exact uniform asymptotic expansion of the total field solution. The uniform expansions obtained are valid in the entire space, including transition regions around the shadow boundaries. The final results are compared with the formulations of two leading uniform theories of edge diffraction, namely, the uniform asymptotic theory and the uniform theory of diffraction. Some unique observations and conclusions are made in relating the two theories.

  16. Effect of design factors on surface temperature and wear in disk brakes

    NASA Technical Reports Server (NTRS)

    Santini, J. J.; Kennedy, F. E.; Ling, F. F.

    1976-01-01

    The temperatures, friction, wear and contact conditions that occur in high energy disk brakes are studied. Surface and near surface temperatures were monitored at various locations in a caliper disk brake during drag type testing, with friction coefficient and wear rates also being determined. The recorded transient temperature distributions in the friction pads and infrared photographs of the rotor disk surface both showed that contact at the friction surface was not uniform, with contact areas constantly shifting due to nonuniform thermal expansion and wear. The effect of external cooling and of design modifications on friction, wear and temperatures was also investigated. It was found that significant decreases in surface temperature and in wear rate can be achieved without a reduction in friction either by slotting the contacting face of the brake pad or by modifying the design of the pad support to improve pad compliance. Both design changes result in more uniform contact conditions on the friction surface.

  17. Electroformed screens with uniform hole size

    NASA Technical Reports Server (NTRS)

    Schaer, G. R.

    1968-01-01

    Efficient method electroforms fine-mesh nickel screens, or plagues, with uniform hole size and accurate spacing between holes. An electroformed nickel mandrel has nonconducting silicone rubber projections that duplicate the desired hole size and shape in the finished nickel screen.

  18. 7 CFR 54.31 - Uniforms.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) MEATS, PREPARED MEATS, AND MEAT PRODUCTS (GRADING, CERTIFICATION, AND STANDARDS) Regulations Miscellaneous § 54.31 Uniforms. All meat... or meat product. [45 FR 19214, Mar. 25, 1980. Redesignated at 46 FR 63203, Dec. 31, 1981] ...

  19. 7 CFR 54.31 - Uniforms.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT (CONTINUED) MEATS, PREPARED MEATS, AND MEAT PRODUCTS (GRADING, CERTIFICATION, AND STANDARDS) Regulations Miscellaneous § 54.31 Uniforms. All meat... or meat product. [45 FR 19214, Mar. 25, 1980. Redesignated at 46 FR 63203, Dec. 31, 1981] ...

  20. School Uniforms: A Blueprint for Legal Challenges.

    ERIC Educational Resources Information Center

    Simonson, Mary Ellen

    1998-01-01

    This article discusses some of the options and strategies available to school districts in defending dress codes which mandate uniforms. Three components are essential to a successful defense: the dress code must bear a reasonable relation to the school's pedagogical purpose, it must include alternative avenues of expression, and it must…