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Sample records for achieving uniform surface

  1. Dosimetric measurements and Monte Carlo simulation for achieving uniform surface dose in pulsed electron beam irradiation facility

    V C Petwal; J N Rao; Jishnu Dwivedi; V K Senecha; K V Subbaiah

    2010-03-01

    A prototype pulsed electron beam irradiation facility for radiation processing of food and medical products is being commissioned at our centre in Indore, India. Analysis of surface dose and uniformity for a pulsed beam facility is of crucial importance because it is influenced by various operating parameters such as beam current, pulse repetition rate (PRR), scanning current profile and frequency, scanning width and product conveying speed. A large number of experiments are required to determine the harmonized setting of these operating parameters for achieving uniform dose. Since there is no readily available tool to set these parameters, use of Monte Carlo methods and computational tools can prove to be the most viable and time saving technique to support the assessment of the dose distribution. In the present study, Monte Carlo code, MCNP, is used to simulate the transport of 10 MeV electron beam through various mediums coming into the beam path and generate an equivalent dose profile in a polystyrene phantom for stationary state. These results have been verified with experimentally measured dose profile, showing that results are in good agreement within 4%. The Monte Carlo simulation further has been used to optimize the overlapping between the successive pulses of a scan to achieve ± 5% dose uniformity along the scanning direction. A mathematical model, which uses the stationary state data, is developed to include the effect of conveyor speed. The algorithm of the model is discussed and the results are compared with the experimentally measured values, which show that the agreement is better than 15%. Finally, harmonized setting for operating parameters of the accelerator are derived to deliver uniform surface dose in the range of 1–13 kGy/pass.

  2. Deposition uniformity inspection in IC wafer surface

    Li, W. C.; Lin, Y. T.; Jeng, J. J.; Chang, C. L.

    2014-03-01

    This paper focuses on the task of automatic visual inspection of color uniformity on the surface of integrated circuits (IC) wafers arising from the layering process. The oxide thickness uniformity within a given wafer with a desired target thickness is of great importance for modern semiconductor circuits with small oxide thickness. The non-uniform chemical vapor deposition (CVD) on a wafer surface will proceed to fail testing in Wafer Acceptance Test (WAT). Early detection of non-uniform deposition in a wafer surface can reduce material waste and improve production yields. The fastest and most low-priced inspection method is a machine vision-based inspection system. In this paper, the proposed visual inspection system is based on the color representations which were reflected from wafer surface. The regions of non-uniform deposition present different colors from the uniform background in a wafer surface. The proposed inspection technique first learns the color data via color space transformation from uniform deposition of normal wafer surfaces. The individual small region statistical comparison scheme then proceeds to the testing wafers. Experimental results show that the proposed method can effectively detect the non-uniform deposition regions on the wafer surface. The inspection time of the deposited wafers is quite compatible with the atmospheric pressure CVD time.

  3. Orbifoldization, covering surfaces and uniformization theory

    Bántay, P

    1998-01-01

    The connection between the theory of permutation orbifolds, covering surfaces and uniformization is investigated, and the higher genus partition functions of an arbitrary permutation orbifold are expressed in terms of those of the original theory.

  4. Controlled uniform coating from the interplay of Marangoni flows and surface-adsorbed macromolecules

    Kim, Hyoungsoo; Um, Eujin; Jacobi, Ian; Button, Ernie; Stone, Howard A

    2016-01-01

    Surface coatings and patterning technologies are essential for various physicochemical applications. In this Letter, we describe key parameters to achieve uniform particle coatings in binary solutions: First, multiple sequential Marangoni flows, set by solute and surfactant simultaneously, prevent non-uniform particle distributions and continuously mix suspended materials during droplet evaporation. Second, we show the importance of particle-surface interactions that can be established by surface-adsorbed macromolecules. To achieve a uniform deposit in a binary mixture a small concentration of surfactant and surface-adsorbed polymer (0.05 wt% each) is sufficient, which offers a new physicochemical avenue for control of coatings.

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

    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…

  6. Dressed for Success: Do School Uniforms Improve Student Behavior, Attendance, and Achievement?

    Scott Imberman; Elisabetta Gentile

    2009-01-01

    Concerns about safety in urban schools has led many school districts to require uniforms for their students. However, we know very little about what impact school uniforms have had on the educational environment. In this paper we use a unique dataset to assess how uniform adoption affects student achievement and behavior in a large urban school district in the southwest. Since each school in the district could decide independently about whether or not to adopt uniforms, we are able to use var...

  7. Precise evaluation of uniform Doo-Sabin surfaces

    2003-01-01

    Using eigenanalysis of uniform Doo-Sabin subdivision surfaces, parameterization approaches for two types of Doo-Sabin subdivision surfaces are developed, and evaluation methods for values and derivatives of Doo-Sabin surfaces at arbitrary parameters are presented by means of non-iterative approaches. Generalized basis functions for Doo-Sabin surfaces are also derived. Thus, the prejudice is disproved further that subdivision surfaces cannot be evaluated precisely.

  8. Uniform algal growth in photobioreactors using surface scatterers

    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.

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

    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.

  10. Continuity of non-uniform recursive subdivision surfaces

    2000-01-01

    Since Doo-Sabin and Catmull-Clark surfaces were proposed in 1978, eigenstructure, convergence and continuity analyses of stationary subdivision have been performed very well, but it has been very difficult to prove the convergence and continuity of non-uniform recursive subdivision surfaces (NURSSes, for short) of arbitrary topology. In fact, so far a problem whether or not there exists the limit surface as well as G1 continuity of a non-uniform Catmull-Clark subdivision has not been solved yet. Here the concept of equivalent knot spacing is introduced. A new technique for eigenanalysis, convergence and continuity analyses of non-uniform Catmull-Clark surfaces is proposed such that the convergence and G1 continuity of NURSSes at extraordinary points are proved. In addition, slightly improved rules for NURSSes are developed. This offers us one more alternative for modeling free-form surfaces of arbitrary topologies with geometric features such as cusps, sharp edges, creases and darts, while elsewhere maintaining the same order of continuity as B-spline surfaces.

  11. Continuity of non-uniform recursive subdivision surfaces

    秦开怀; 王华维

    2000-01-01

    Since Doo-Sabin and Catmull-Clark surfaces were proposed in 1978, eigenstructure, convergence and continuity analyses of stationary subdivision have been performed very well, but it has been very difficult to prove the convergence and continuity of non-uniform recursive subdivision surfaces (NURSSes, for short) of arbitrary topology. In fact, so far a problem whether or not there exists the limit surface as well as G1 continuity of a non-uniform Catmull-Clark subdivision has not been solved yet. Here the concept of equivalent knot spacing is introduced. A new technique for eigenanaly-sis, convergence and continuity analyses of non-uniform Catmull-Clark surfaces is proposed such that the convergence and G1 continuity of NURSSes at extraordinary points are proved. In addition, slightly improved rules for NURSSes are developed. This offers us one more alternative for modeling free-form surfaces of arbitrary topologies with geometric features such as cusps, sharp edges, creases and darts, while elsewhere ma

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

    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.

  13. Line printing solution-processable small molecules with uniform surface profile via ink-jet printer.

    Liu, Huimin; Xu, Wei; Tan, Wanyi; Zhu, Xuhui; Wang, Jian; Peng, Junbiao; Cao, Yong

    2016-03-01

    Line printing offers a feasible approach to remove the pixel well structure which is widely used to confine the ink-jet printed solution. In the study, a uniform line is printed by an ink-jet printer. To achieve a uniform surface profile of the printed line, 10vol% low-volatile solvent DMA (3,4-Dimethylanisole) is mixed with high-volatile solvent Pxy (p-xylene) as the solvent. After a solution-processable small molecule is dissolved, the surface tension of DMA solution becomes lower than that of Pxy solution, which creates an inward Marangoni flow during the solvent evaporation. The inward Marangoni flow balances out the outward capillary flow, thereby forming a flat film surface. The line width of the printed line depends on the contact angle of the solution on the hole injection layer.

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

    B. Pfeil

    2013-04-01

    Full Text Available 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.

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

    T. Takahashi

    2012-08-01

    Full Text Available 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.

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

    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.

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

    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…

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

    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…

  19. Layer uniformity in glucose oxidase immobilization on SiO{sub 2} surfaces

    Libertino, Sebania [CNR - IMM unita Catania, Stradale Primosole 50, 95121 Catania (Italy)], E-mail: sebania.libertino@imm.cnr.it; Scandurra, Antonino [Laboratorio Superfici e Interfasi (SUPERLAB), Consorzio Catania Ricerche, Stradale Primosole 50, 95121 Catania (Italy); Aiello, Venera [CNR - IMM unita Catania, Stradale Primosole 50, 95121 Catania (Italy); Universita degli Studi di Catania, Dipartimento di Chimica Biologica, Chimica Medica e Biologia Molecolare, Viale A.Doria, 6, 95125 Catania (Italy); Giannazzo, Filippo [CNR - IMM unita Catania, Stradale Primosole 50, 95121 Catania (Italy); Sinatra, Fulvia [Universita degli Studi di Catania, Dipartimento di Scienze Biomediche, Via S. Sofia, 87, 95100 Catania (Italy); Renis, Marcella [Universita degli Studi di Catania, Dipartimento di Chimica Biologica, Chimica Medica e Biologia Molecolare, Viale A.Doria, 6, 95125 Catania (Italy); Fichera, Manuela [CNR - IMM unita Catania, Stradale Primosole 50, 95121 Catania (Italy)

    2007-09-30

    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{sub 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.

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

    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.

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

    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

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

    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.

  3. An efficient plate heater with uniform surface temperature engineered with effective thermal materials

    Liu, Yichao; He, Sailing; Ma, Yungui

    2014-01-01

    Extended from its electromagnetic counterpart, transformation thermodynamics applied to thermal conduction equations can map a virtual geometry into a physical thermal medium, realizing the manipulation of heat flux with almost arbitrarily desired diffusion paths, which provides unprecedented opportunities to create thermal devices unconceivable or deemed impossible before. In this work we employ this technique to design an efficient plate heater that can transiently achieve a large surface of uniform temperature powered by a small thermal source. As opposed to the traditional approach of relying on the deployment of a resistor network, our approach fully takes advantage of an advanced functional material system to guide the heat flux to achieve the desired temperature heating profile. A different set of material parameters for the transformed device has been developed, offering the parametric freedom for practical applications. As a proof of concept, the proposed devices are implemented with engineered therm...

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

    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.

  5. Impact of non-uniform surface magnetic fields on stellar winds

    Holzwarth, V R

    2005-01-01

    Observations of active stars reveal highly non-uniform surface distributions of magnetic flux. Theoretical models considering magnetised stellar winds however often presume uniform surface magnetic fields, characterised by a single magnetic field strength. The present work investigates the impact of non-uniform surface magnetic field distributions on the stellar mass and angular momentum loss rates. The approach of Weber & Davis (1967) is extended to non-equatorial latitudes to quantify the impact of latitude-dependent magnetic field distributions over a large range of stellar rotation rates and thermal wind properties. The analytically prescribed field patterns are dominated by magnetic flux concentrations at intermediate and high latitudes. The global stellar mass loss rates are found to be rather insensitive to non-uniformities of the surface magnetic field. Depending on the non-uniformity of the field distribution, the angular momentum loss rates deviate in contrast at all rotation rates between -60% ...

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

    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.

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

    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.

  8. Ensuring uniformity of strengthening for machine parts surfaces by shot-peening

    Z.A. Stotsko

    2010-11-01

    Full Text Available Purpose: of this paper is developing the mathematical models of shot-peening, in which is reflected moving shot-peening head or machine parts surfaces during treating that will achieve uniformity of treatment machine parts.Design/methodology/approach: The main methods used for the theoretical research are mathematical modelling, integral calculus, fundamentals of analytic geometry, probability theory. It is used approved enough and well known numerical methods for calculations after mathematical models.Findings: Method of mathematical modeling for shot-peening is developed based on the energy conception. Mathematical model in which is reflected moving shot-peened head or machine parts surfaces during treating is created. It allows forecasting the characteristics of surface quality depending on the technological modes of treatment.Research limitations/implications: It is planned developing and improving the methods of shot-peening mathematical modeling in future research by extending theirs for the curvilinear treated surfaces, which has movement relative to the nozzle of shot-peening head after the different laws of motion, and for different kinds of materials, especially for metal joint endoprosthesis biomaterials.Practical implications: has the applied software, elaborated on the basis of the models, that allows providing for automation of calculations of the characteristics of surface quality depending on the technological modes of treatment.Originality/value: It is pioneered receiving functional dependences in which is reflected moving shot-peened head or machine parts surfaces during treating. Created functional dependences takes into account the distribution of characteristics of working medium (mass and velocity all along the cross-sections of shot blast.

  9. Constructing iterative non-uniform B-spline curve and surface to fit data points

    LIN Hongwei; WANG Guojin; DONG Chenshi

    2004-01-01

    In this paper, based on the idea of profit and loss modification, we present the iterative non-uniform B-spline curve and surface to settle a key problem in computer aided geometric design and reverse engineering, that is, constructing the curve (surface)fitting (interpolating) a given ordered point set without solving a linear system. We start with a piece of initial non-uniform B-spline curve (surface) which takes the given point set as its control point set. Then by adjusting its control points gradually with iterative formula,we can get a group of non-uniform B-spline curves (surfaces) with gradually higher precision. In this paper, using modern matrix theory, we strictly prove that the limit curve (surface) of the iteration interpolates the given point set. The non-uniform B-spline curves (surfaces) generated with the iteration have many advantages, such as satisfying the NURBS standard, having explicit expression, gaining locality, and convexity preserving,etc.

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

    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).

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

    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.

  12. Achieving Uniform Carriers Distribution in MBE Grown Compositionally Graded InGaN Multiple-Quantum-Well LEDs

    Mishra, Pawan

    2015-05-06

    We investigated the design and growth of compositionally-graded InGaN multiple quantum wells (MQW) based light-emitting diode (LED) without an electron-blocking layer (EBL). Numerical investigation showed uniform carrier distribution in the active region, and higher radiative recombination rate for the optimized graded-MQW design, i.e. In0→xGa1→(1-x)N / InxGa(1-x)N / Inx→0Ga(1-x)→1N, as compared to the conventional stepped-MQW-LED. The composition-grading schemes, such as linear, parabolic, and Fermi-function profiles were numerically investigated for comparison. The stepped- and graded-MQW-LED were then grown using plasma assisted molecular beam epitaxy (PAMBE) through surface-stoichiometry optimization based on reflection high-energy electron-diffraction (RHEED) in-situ observations. Stepped- and graded-MQW-LED showed efficiency roll over at 160 A/cm2 and 275 A/cm2, respectively. The extended threshold current density roll-over (droop) in graded-MQW-LED is due to the improvement in carrier uniformity and radiative recombination rate, consistent with the numerical simulation.

  13. Uniform Regularity and Vanishing Viscosity Limit for the Free Surface Navier-Stokes Equations

    Masmoudi, Nader; Rousset, Frederic

    2016-09-01

    We study the inviscid limit of the free boundary Navier-Stokes equations. We prove the existence of solutions on a uniform time interval by using a suitable functional framework based on Sobolev conormal spaces. This allows us to use a strong compactness argument to justify the inviscid limit. Our approach does not rely on the justification of asymptotic expansions. In particular, we get a new existence result for the Euler equations with free surface from the one for Navier-Stokes.

  14. Influence of Gloss and Surface Roughness of Coated Ink Jet Papers on Print Uniformity

    Ivana Jurič

    2013-12-01

    Full Text Available The final print quality depends on the quality of the digital image as well as the properties of the printing system, the inks and the paper used. One of the most widely used digital printing technologies is ink jet, where ink is ejected directly onto a substrate from a jet device driven by an electronic signal. Most ink jet inks have low viscosity and low surface tension, which pose high demands upon the surface properties of the paper. The aim of this study was to investigate the influence of paper properties of commercially available papers suitable for ink jet printing on print mottle, non-uniformity. We used two high glossy, one glossy, one semi-glossy and two matte papers. For the assessment of the surface properties, we measured surface roughness with the portable Roughness Tester TR 200. We also measured surface gloss with QIP Glossmaster. To characterise the print mottle we used the image analysis method – Gray level co-occurrence matrix (GLCM. Print mottle was estimated according to five GLCM parameters: Contrast, Correlation, Entropy, Energy and Homogeneity. Results obtained in this paper showed that the surface properties of paper are not in any direct relation with print uniformity.

  15. Uniform surface polished method of complex holes in abrasive flow machining

    A-Cheng WANG; Lung TSAI; Kuo-Zoo LIANG; Chun-Ho LIU; Shi-Hong WENG

    2009-01-01

    Abrasive flow machining(AFM) is an effective method that can remove the recasting layer produced by wire electrical discharge machining(WEDM). However, the surface roughness will not be easily uniform when a complex hole is polished by this method. CFD numerical method is aided to design good passageways to find the smooth roughness on the complex hole in AFM. Through the present method, it reveals that the shear forces in the polishing process and the flow properties of the medium in AFM play the roles in controlling the roughness on the entire surface. A power law model was firstly set up by utilizing the effect of shear rates on the medium viscosities, and the coefficients of the power law would be found by solving the algebraic equation from the relations between the shear rates and viscosities. Then the velocities, strain rates and shear forces of the medium acting on the surface would be obtained in the constant pressure by CFD software. Finally, the optimal mold core put into the complex hole could be designed after these simulations. The results show that the shear forces and strain rates change sharply on the entire surface if no mold core is inserted into the complex hole, whereas they hardly make any difference when the core shape is similar to the complex hole. Three experimental types of mold core were used. The results demonstrate that the similar shape of the mold core inserted into the hole could find the uniform roughness on the surface.

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

    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.

  17. The Electric Field of a Uniformly Charged Non-Conducting Cubic Surface

    McCreery, Kaitlin

    2016-01-01

    As an integrative and insightful example for undergraduates learning about electrostatics, we discuss how to use symmetry, Coulomb's Law, superposition, Gauss's law, and visualization to understand the electric field produced by a non-conducting cubic surface that is covered with a uniform surface charge density. We first discuss how to deduce qualitatively, using only elementary physics, the surprising fact that the electric field inside the cubic surface is nonzero and has a complex structure, pointing inwards towards the cube center from the midface of each cube and pointing outwards towards each edge and corner. We then discuss how to understand the quantitative features of the electric field by plotting an analytical expression for E along symmetry lines and on symmetry surfaces. This example would be a good choice for group problem solving in a recitation or flipped classroom.

  18. Efficient Analysis of Surface-Wire Configurations Using AIM and Best Uniform Rational Approximation

    DONG Hailin; GONG Shuxi; WANG Xing; ZHANG Penfei; ZHAO Bo

    2015-01-01

    The Adaptive integral method (AIM) in conjunction with the best uniform approximation tech-nique is applied to analyze the electromagnetic problems of surface-wire junction geometries over a wide frequency band. To improve the computation efficiency, the best uniform approximation method is utilized. The AIM can reduce memory requirements and accelerate the matrix-vector multiplications in iterative process. Some numeri-cal examples are shown to demonstrate the efficiency and accuracy of the proposed method. Compared with the di-rect solution method and Asymptotic waveform evaluation (AWE) technique, the proposed technique is found to be efficient in a broadband with the lower Central processing unit (CPU) time required and without loss of accuracy.

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

    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

  20. Large-Area Au-Nanoparticle-Functionalized Si Nanorod Arrays for Spatially Uniform Surface-Enhanced Raman Spectroscopy.

    Lin, Dongdong; Wu, Zilong; Li, Shujie; Zhao, Wenqi; Ma, Chongjun; Wang, Jie; Jiang, Zuimin; Zhong, Zhenyang; Zheng, Yuebing; Yang, Xinju

    2017-01-18

    In this study, large-area hexagonal-packed Si nanorod (SiNR) arrays in conjunction with Au nanoparticles (AuNPs) were fabricated for surface-enhanced Raman spectroscopy (SERS). We have achieved ultrasensitive molecular detection with high reproducibility and spatial uniformity. A finite-difference time-domain simulation suggests that a wide range of three-dimensional electric fields are generated along the surfaces of the SiNR array. With the tuning of the gap and diameter of the SiNRs, the produced long decay length (>130 nm) of the enhanced electric field makes the SERS substrate a zero-gap system for ultrasensitive detection of large biomolecules. In the detection of R6G molecules, our SERS system achieved an enhancement factor of >10(7) with a relative standard deviation as small as 3.9-7.2% over 30 points across the substrate. More significantly, the SERS substrate yielded ultrasensitive Raman signals on long amyloid-β fibrils at the single-fibril level, which provides promising potentials for ultrasensitive detection of amyloid aggregates that are related to Alzheimer's disease. Our study demonstrates that the SiNRs functionalized with AuNPs may serve as excellent SERS substrates in chemical and biomedical detection.

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

    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.

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

    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.

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

    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. Controlled Acoustic Bass System (CABS) A Method to Achieve Uniform Sound Field Distribution at Low Frequencies in Rectangular Rooms

    Celestinos, Adrian; Nielsen, Sofus Birkedal

    2008-01-01

    The sound field produced by loudspeakers at low frequencies in small- and medium-size rectangular listening rooms is highly nonuniform due to the multiple reflections and diffractions of sound on the walls and different objects in the room. A new method, called controlled acoustic bass system (CABS......), is introduced. The system utilizes front loudspeakers and extra loudspeakers on the opposite wall of the room processed to cancel out the rear-wall reflections, which effectively conveys a more uniform sound field. The system works in the time domain and presents good performance over the loudspeaker low...

  5. Rivulet flow round a horizontal cylinder subject to a uniform surface shear stress

    Paterson, C.

    2014-09-14

    © 2014 © The Author, 2014. Published by Oxford University Press; all rights reserved. For Permissions, please email: journals.permissions@oup.com. The steady flow of a slowly varying rivulet with prescribed flux in the azimuthal direction round a large stationary horizontal cylinder subject to a prescribed uniform azimuthal surface shear stress is investigated. In particular, we focus on the case where the volume flux is downwards but the shear stress is upwards, for which there is always a solution corresponding to a rivulet flowing down at least part of one side of the cylinder. We consider both a rivulet with constant non-zero contact angle but slowly varying width (that is, de-pinned contact lines) and a rivulet with constant width but slowly varying contact angle (that is, pinned contact lines), and show that they have qualitatively different behaviour. When shear is present, a rivulet with constant non-zero contact angle can never run all the way from the top to the bottom of the cylinder, and so we consider the scenario in which an infinitely wide two-dimensional film of uniform thickness covers part of the upper half of the cylinder and \\'breaks\\' into a single rivulet with constant non-zero contact angle. In contrast, a sufficiently narrow rivulet with constant width can run all the way from the top to the bottom of the cylinder, whereas a wide rivulet can do so only if its contact lines de-pin, and so we consider the scenario in which the contact lines of a wide rivulet de-pin on the lower half of the cylinder.

  6. Porogen effects in synthesis of uniform micrometer-sized poly(divinylbenzene) microspheres with high surface areas.

    Hao, Dong-xia; Gong, Fang-ling; Wei, Wei; Hu, Guo-hua; Ma, Guang-hui; Su, Zhi-guo

    2008-07-01

    A new method of synthesizing uniform poly(divinylbenzene) (polyDVB) microspheres with high specific surface areas was designed by combining Shirasu porous glass (SPG) membrane emulsification, suspension polymerization, and post-crosslinking techniques. It was shown that the physicochemical properties of porogens have a great influence on the size distribution and porous features of microspheres. The low aqueous solubility of porogen facilitated preparation of uniform emulsions and microspheres, and high aqueous solubility led to polydispersed emulsions and poor microsphere yields. Such aqueous solubility effects can be tailored by adding a low molecular weight polystyrene (LPST) as costabilizer in porogen, thus improving the uniformity of microspheres. Moreover, different affinities of porogens for copolymers demonstrate various contributions to specific surface areas of microspheres in suspension polymerization especially post-crosslinking. Solvating porogen requires a much higher addition than nonsolvating porogen to obtain equal specific surface areas in polymerization, but has more potential to enhance the specific surface area in post-crosslinking. Two kinds of uniform microspheres were obtained with high specific surface areas, up to 706.6 m2/g by heptane and 937.5 m2/g by toluene.

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

    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.

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

    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…

  9. 暖体假人表面温度的均匀性%Surface temperature uniformity of thermal manikin

    王毅; 王铭; 邹钺; 李书政; 刘赟

    2012-01-01

    Thermal manikin is equipped with heating wire which serves as internal heat source to simulate the human body heat dissipating, and mainly used for testing the thermal resistance of garments, whose surface temperature uniformity is critical. The aim of this study is to find out the main factors influencing the uniformity of the temperature on the surface of thermal manikin and how to meet the requirement of uniform distribution of the temperature. The arrangement of the heating wire and test method of the temperature are presented. Comparative experiments are conducted and temperature distribution rule on the surface of the thermal manikin is observed. The test results indicate that the laying interval of heating wire, thickness of thermal manikin's skin cover, and the side boundary conditions on the surface all have influence on the temperature uniformity to different extents.%暖体假人是以电热丝作为内热源来模拟人体散热的一种设备,主要用于测试服装热阻,对表面温度均匀性要求极高.为找出影响假人表面温度均匀性的主要因素,达到假人表面温度分布均匀的要求,提出假人表面电热丝的敷设方案和温度测试方案.通过对比实验,观察假人皮肤表面的温度分布规律.结果表明:电热丝的敷设间隔、假人皮肤的覆盖厚度以及侧面边界条件对假人表面温度均匀性都有不同程度的影响.

  10. Numerical investigation of the film uniformity during the surface coating of charged nanoparticles in a low pressure plasma reactor

    Pourali, N.; Foroutan, G., E-mail: foroutan@sut.ac.ir

    2016-07-15

    The uniformity of film deposition on charged nanoparticles, trapped near the sheath of a capacitively coupled plasma reactor, is studied by numerical simulation of the multi-fluid plasma equations, surface deposition processes, and nanoparticle heating effects. It is found that the anisotropy in the ion flux onto the powered electrode may be hold responsible for the film nonuniformity. The nonuniformity increases with increasing of the particle radius, although small particles lose sphericity faster than the large particles. Because of the electron temperature dependence of the deposition rate and the incident ion flux, higher electron temperatures lead to more nonuniform film deposition. However, the uniformity is improved and the sphericity is restored by the increase in the background gas pressure and/or temperature. - Highlights: • The surface coating of charged nanoparticles in a low pressure plasma is investigated by numerical simulation of the multi-fluid plasma equations. • The deposition rate on the particle surface is not spatially uniform. • The nonuniformity in the film deposition is attributed to the anisotropy of the ion flux. • The nonuniformity increases with distance from the sheath edge.

  11. The patterns of surface capillary-gravity short-crested waves with uniform current fields in coastal waters

    Hu Huang; Jia Fu

    2006-01-01

    A fully three-dimensional surface gravitycapillary short-crested wave system is studied as two progressive wave-trains of equal amplitude and frequency, which are collinear with uniform currents and doubly-periodic in the horizontal plane, are propagating at an angle to each other. The first-and second-order asymptotic analytical solutions of the short-crested wave system are obtained via a perturbation expansion in a small parameter associated with the wave steepness, therefore depicting a series of typical three-dimensional wave patterns involving currents, shallow and deep water, and surface capillary waves, and comparing them with each other.

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

    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.; Gonzalez-Davila, 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.; Kortzinger, A.; Landschutzer, P.; Lauvset, S.K.; Lefevre, 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.; Rios, A.F.; Santana-Casiano, J.M.; Salisbury, J.; Sarma, V.V.S.S.; et al

    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...

  13. Effect of linear surface-charge non-uniformities on the electrokinetic ionic-current rectification in conical nanopores.

    Qian, Shizhi; Joo, Sang W; Ai, Ye; Cheney, Marcos A; Hou, Wensheng

    2009-01-15

    The electrokinetic ionic-current rectification in a conical nanopore with linearly varying surface-charge distributions is studied theoretically by using a continuum model composed of a coupled system of the Nernst-Planck equations for the ionic-concentration field and the Poisson equation for the electric potential in the electrolyte solution. The numerical analysis includes the electrochemistry inside reservoirs connected to the nanopore, neglected in previous studies, and more precise accounts of the ionic current are provided. The surface-charge distribution, especially near the tip of the nanopore, significantly affects the ionic enrichment and depletion, which, in turn, influence the resulting ionic current and the rectification. It is shown that non-uniform surface-charge distribution can reverse the direction, or sense, of the rectification. Further insights into the ionic-current rectification are provided by discussing the intriguing details of the electric potential and ionic-concentration fields, leading to the rectification. Rationale for future studies on ionic-current rectification, associated with other non-uniform surface-charge distributions and electroosmotic convection for example, is discussed.

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

    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.

  15. Application of nanosecond-pulsed dielectric barrier discharge for biomedical treatment of topographically non-uniform surfaces

    Ayan, H; Staack, D; Mukhin, Y; Starikovskii, A; Fridman, A [Department of Mechanical Engineering and Mechanics, College of Engineering, Drexel University, Philadelphia, PA 19104 (United States); Fridman, G [School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA 19104 (United States); Gutsol, A [Chevron Energy Technology Company, Richmond, CA 94802 (United States); Friedman, G [Department of Electrical and Computer Engineering, College of Engineering, Drexel University, Philadelphia, PA 19104 (United States)

    2009-06-21

    Antimicrobial effectiveness of a nanosecond-pulsed dielectric barrier discharge (DBD) was investigated and compared with that of a microsecond-pulsed DBD. Experiments were conducted on the Escherichia coli bacteria covering a topographically non-uniform agar surface acting as one of the DBD electrodes. They reveal that the nanosecond-pulsed DBD can inactivate bacteria in recessed areas whereas the microsecond-pulsed and conventional DBDs fail to do so. Charged species (electrons and ions) appear to play the major role in the bacteria inactivation with the nanosecond-pulsed DBD. Moreover, the nanosecond-pulsed DBD kills bacteria significantly faster than its microsecond-pulsed counterpart.

  16. MHD flow and heat transfer from continuous surface in uniform free stream of non-Newtonian fluid

    2007-01-01

    An analysis is carried out to study the steady flow and heat transfer characteristics from a continuous flat surface moving in a parallel free stream of an electrically conducting non-Newtonian viscoelastic fluid. The flow is subjected to a transverse uniform magnetic field. The constitutive equation of the fluid is modeled by that for a second grade fluid. Numerical results are obtained for the distribution of velocity and temperature profiles. The effects of various physical parameters like viscoelastic parameter, magnetic parameter and Prandtl number on various momentum and heat transfer characteristics are discussed in detail and shown graphically.

  17. Revisiting the Challenges in Fabricating Uniform Coatings with Polyfunctional Molecules on High Surface Energy Materials

    Stephanie Oyola-Reynoso

    2015-12-01

    Full Text Available Modifying the chemistry of a surface has been widely used to influence interfacial properties of a material or nature of interaction between two materials. This article provides an overview on the role of polyfunctional molecules, specifically silanes, in surface modification of polar surfaces (bearing soft nucleophiles. An emphasis on the mechanism of the reaction in the presence of adsorbed water, where the modifying reagents are hydrolysable, is discussed. To highlight the complexity of the reaction, modification of paper with trichlorosilanes is highlighted. Preparation of hydrophobic cellulosic paper, and structure–property relations under different treatment conditions is used to highlight that a monolayer is not always formed during the surface modification. Gel-formation via step-growth polymerization suggests that at the right monomer:adsorbed water ratio, a monolayer will not form but rather self-assembly driven particle formation will occur leading to a textured surface. The review highlights recent work indicating that the focus on monolayer formation, is at the very least, not always the case but gel formation, with concomitant self-assembly, might be the culprit in understanding challenges associated with the use of polyfunctional molecules in surface modification.

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

    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.

  19. Gela, Italy, Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    1983-11-03

    manual table is also presented for surface wind meeting INSTHUINTE CLASS conditions as follows: Ceiling 200 through lh0 feet inclusive with visibility...OBSERVATIONS Ui AFETAC 0 8 5 tCI . A] yo s 0 Oi T’. UMAEo.-St! -I AL L MT AtL’ ~Ck WID T A SURFACE WINDS - F .EArH: ST VI "t L PERCENTAGE FREQUENCY OF WIND...temperature Lombined; tuid again for dry-bulb, wet-bulb, and dew-point tempera - tures separately. Total observations for thc.;e four Items is also

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

    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.

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

    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

  2. Fort Belvoir, Alexandria, Virginia. Revised Uniform Summary of Surface Weather Observations (RUSSWO)

    1972-09-07

    iEATHER SERVICE/MAC PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 9377.’ FtIRT BELVilIR VA/OAVISON AF _ 57-70 ICT STATION...ETAC/USAF SURFACE WINDS 3 AIR ,EATI- Elt SFRVICE/HAC PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 9237a. FoiRT oFL VfIR...PSYCHROMETRIC SUMMARY ; AIR V, EATIIER SEkVECEIMAC ŝ)_) FJRT 8-LVrjjR VA/IIAVISIN AAr 57,70 IcT " STATION - STATION NAME - YEARS MONTH i i PAG I -Qj3k

  3. Unsteady MHD flow of a dusty nanofluid past a vertical stretching surface with non-uniform heat source/sink

    C. Sulochana

    2016-02-01

    Full Text Available We analyzed the momentum and heat transfer characteristics of unsteady MHD flow of a dusty nanofluid over a vertical stretching surface in presence of volume fraction of dust and nano particles with non uniform heat source/sink. We considered two types of nanofluids namely Ag-water and Cu-water embedded with conducting dust particles. The governing equations are transformed in to nonlinear ordinary differential equations by using similarity transformation and solved numerically using Shooting technique. The effects of non-dimensional governing parameters on velocity and temperature profiles for fluid and dust phases are discussed and presented through graphs. Also, the skin friction coefficient and Nusselt number are discussed and presented for two dusty nanofluids separately in tabular form. Results indicate that an increase in the volume fraction of dust particles enhances the heat transfer in Cu-water nanofluid compared with Ag-water nanofluid and a raise in the volume fraction of nano particles shows uniform heat transfer in both Cu-water and Ag-water nanofluids.

  4. Malmstrom AFB, Montana. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    1984-02-01

    0 10 .0 6.6 1.5 1.9 81 1.6 2.. 65 T 2ACL T2AC; TRAC ; ..3 .; .-11 4.4. ToACt. 1.4. *.4 R5 .9 9.0 3.4 11 .1 .0 .1 .0 TOACr .S 2.T R. 11.1 83 1 1 2.0...9.5 3.8 .o, .r0 .3 .3 TR’ACE 3.9 3.3 6.- 30, . 49 . 10.6 7.3 12.1 TRACE. 2.1 _a 3. - .a- . 2.1 7.3. TRAC . A.. 47. 9 9.1 .1 28.8 5.9 1. ; 4.5 .3 .3 2...34 Vtt t GLOBAL CLIMATOLOGY 9RANiCH US AFETAC SURFACE WINDS ATP WEATHER SERVICE/IPAC PERCENTAGE FREQUENCY OF WIND DIRECTION

  5. Asteroseismic measurement of slow, nearly uniform surface-to-core rotation in the main-sequence F star KIC 9244992

    Saio, Hideyuki; Kurtz, Donald W.; Takata, Masao;

    2015-01-01

    We have found a rotationally split series of core g-mode triplets and surface p-mode multiplets in a main-sequence F star, KIC 9244992. Comparison with models shows that the star has a mass of about 1.45 M-circle dot, and is at an advanced stage of main-sequence evolution in which the central......, obtained from p-mode splittings, is 66 d, slightly slower than the rotation of 64 d in the core, measured by g-mode splittings. KIC 9244992 is similar to KIC 11145123 in that both are near the end of main-sequence stage with very slow and nearly uniform rotation. This indicates the angular momentum...

  6. Uniform magnesium oxide adsorbents

    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.

  7. Turbulent Variance Characteristics of Temperature and Humidity over a Non-uniform Land Surface for an Agricultural Ecosystem in China

    GAO Zhiqiu; BIAN Lingen; CHEN Zhigang; Michael SPARROW; ZHANG Jiahua

    2006-01-01

    This paper describes the application of the variance method for flux estimation over a mixed agricultural region in China. Eddy covariance and flux variance measurements were conducted in a near-surface layer over a non-uniform land surface in the central plain of China from 7 June to 20 July 2002. During this period, the mean canopy height was about 0.50 m. The study site consisted of grass (10% of area), beans (15%), corn (15%) and rice (60%). Under unstable conditions, the standard deviations of temperature and water vapor density (normalized by appropriate scaling parameters), observed by a single instrument,followed the Monin-Obukhov similarity theory. The similarity constants for heat (CT) and water vapor (Cq) were 1.09 and 1.49, respectively. In comparison with direct measurements using eddy covariance techniques, the flux variance method, on average, underestimated sensible heat flux by 21% and latent heat flux by 24%, which may be attributed to the fact that the observed slight deviations (20% or 30% at most) of the similarity "constants" may be within the expected range of variation of a single instrument from the generally-valid relations.

  8. School Uniforms. Research Brief

    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?").…

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

    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.

  10. Rapid Discrimination of Chlorpheniramine Maleate and Assessment of Its Surface Content Uniformity in a Pharmaceutical Formulation by NIR-CI Coupled with Statistical Measurement

    Luwei Zhou

    2014-01-01

    Full Text Available This study demonstrated that near infrared chemical imaging (NIR-CI was a rapid and nondestructive technique for discrimination of chlorpheniramine maleate (CPM and assessment of its surface content uniformity (SCU in a pharmaceutical formulation. The characteristic wavenumber method was used for discriminating CPM distribution on the tablet surface. To assess the surface content uniformity of CPM, binary image and statistical measurement were proposed. Furthermore, high-performance liquid chromatography (HPLC was used as reference method for accurately determining volume content of CPM in the sample. Moreover, HPLC was performed to assess volume content uniformity (VCU of CPM in whole region and part region of the tablets. The NIR-CI result showed that the spatial distribution of CPM was heterogeneous on the tablet surface. Through the comparison of content uniformity of CPM determined by NIR-CI and HPLC, respectively, it demonstrated that a high degree of VCU did not imply a high degree of SCU of the samples. These results indicate that HPLC method is not suitable for testing SCU, and this has been verified by NIR-CI. This study proves the feasibility of NIR-CI for rapid discrimination of CPM and assessment of its SCU, which is helpful for the quality control of commercial CPM tablets.

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

    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.

  12. MHD Instability Analysis of Liquid Metal Free Surface Jet Flow in Non-Uniform Magnetic Fields (Part Ⅱ)

    XUZenyu; KANGWeishan; PANChuanjie; DENHongyin; ZHANGYanxu

    2003-01-01

    In lost paper of magneto-hydrodynamic instability analysis of liquid metal free surface jet flow (Part Ⅰ), the magneto-hydrodynamic instability was analyzed for the jet flow in a transverse non-uniform magnetic field, BT. But, as all known, for the real conditions of liquid metal limiter-divertor plasma-facing components are in toroidal and poloidal fields. So, we try to analyze the magneto-hydrodynamic instability of the jet flow (hereby only for circular shape cross section jet flow) in the zone of non-uniform magnetic fields,

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

    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.

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

    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

  15. Uniform polyhedra

    Melikhov, Sergey A

    2011-01-01

    Although topological and uniform approaches to foundations of what was then known as Analysis Situs originated in the same works by M. Frechet and F. Riesz, uniform spaces hopelessly lagged behind in development, and were never taken seriously in algebraic and geometric topology, due in part to the lack of a coherent theory of quotient spaces, and of a reasonable notion of a polyhedron in the uniform category. Yet there are painful side effects of the usual topological foundations: for instance, the non-metrizability of the cone over the real line, and the non-metrizability of RP^\\infty (as a CW-complex or as the geometric realization of a simplicial set). We show that (the topology of) quotient uniformity is, after all, far nicer than quotient topology in the context of metrizable spaces, and that (metrizable, possibly locally infinite-dimensional) uniform polyhedra do exist - and behave nicely - which appears to provide a satisfactory solution to an old open-ended problem by Isbell.

  16. A uniformly valid series solution to the unsteady stagnation-point flow towards an impulsively stretching surface

    2010-01-01

    The paper studies the problem of the unsteady two-dimensional stagnation-point flow of an incompressible viscous fluid over a flat deformable sheet. The flow is started impulsively from rest and the sheet is suddenly stretched in its own plane with a velocity proportional to the distance from the stagnation point. An analytical series solution is obtained by means of the homotopy analysis method (HAM). Also, the homotopy-Pade′ technique is employed. An explicit formula for the local friction coefficient is provided. The present formula, different from the perturbation solution, is accurate and uniformly valid for all dimensionless time in the whole spatial region and for all possible values of physical parameter λ, defined as the ratio of the potential flow velocity to the sheet sudden stretching velocity. Numerical tests are done to verify the present formula for its validity and accuracy.

  17. 均匀B样条曲线曲面的小波表示%Wavelets-Based Representation of Uniform B-Spline Curves and Surfaces

    赵罡; 穆国旺; 闫光荣; 朱心雄

    2001-01-01

    Wavelets-based representation provides a more flexible method for expressing curves and surfaces in different resolution levels. For uniform B-spline curves and surfaces, a unified expression can be adopted after decomposition to describe the wavelets for the interior and boundaries of the domain defined, and hence the multiplication is the only operation be needed to wavelets reconstruction. This results in high efficiency for the computation. The paper describes, from the point of geometry view, the principles and methods of realizing wavelets-based multiresolution representation of uniform cubic B-spline curves and surfaces.%小波基为曲线曲面带来了更为灵活的表达方式。均匀B样条曲线曲面在经过小波分解以后所得到的小波在定义域边界与内部可以采用统一的表达式,在进行小波重构时仅需作乘法运算,计算效率高。本文试图从几何概念出发由浅入深地论述基于小波的均匀三次B样条曲线曲面多分辨表示的原理及其实现。

  18. Theoretical Analysis of Unit Friction Force Working on the Metal Contact Surface with the Roll Change during Feedstock with Non-Uniform Temperature Distribution Rolling Process

    Sygut P.

    2016-06-01

    Full Text Available The paper presents the results of theoretical studies influence of non-uniform temperature distribution along the feedstock length to the unit friction force working on the metal contact surface with the roll change during the round bars 70 mm in diameter continuous rolling process. This value is one of the major factors affecting the grooves wear during the rolling process. The studies were carried out based on the actual engineering data for 160 × 160 mm square cross-section feedstock of steel S355J0. Numerical modelling of the rolling process was performed using Forge2008®, a finite-element based computer program.

  19. Solvothermal synthesis of LiFePO{sub 4} nanoplates with (010) plane and the uniform carbon coated on their surface by esterification reaction

    Ma, Zhipeng [Hebei Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China); Shao, Guangjie, E-mail: shaoguangjie@ysu.edu.cn [Hebei Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China); State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Wang, Xu [The Equipment Research Institute of the General Logistic Department of the CPLA, Beijing 100010 (China); Song, Jianjun; Wang, Guiling; Liu, Tingting [Hebei Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2014-02-14

    A facile solvothermal synthesis and esterification reaction combined with a high temperature calcination technique has been developed to prepare the uniform carbon coating LiFePO{sub 4} nanoplates. The carbon coating LiFePO{sub 4} nanoplates are investigated by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscope (SEM), transmission electron microscope (TEM), galvanostatic intermittent titration technique (GITT) and galvanostatic charge–discharge test. A reasonable growth mechanism of LiFePO{sub 4} nanoplates is proposed on the basis of time dependent experimental results. The results show that each nanoplate is a LiFePO{sub 4} single crystal with the large (010) plane. According to Raman spectroscopy analysis, carbon is uniformly coated on the surface of LiFePO{sub 4} nanoplates. Electrochemical test results also indicate that the carbon coating LiFePO{sub 4} nanoplates exhibit a high reversible specific capacity of 144.8 mAh g{sup −1} at 0.5 C and 116.9 mAh g{sup −1} under lower discharging rate at −20 °C. - Highlights: • LiFePO{sub 4} nanoplates prepared by facile solvothermal synthesis expose large (010) plane. • The polyester network formed by the esterification reaction could entirely wrap LiFePO{sub 4}. • The polyester wrapped on the surface of LiFePO{sub 4} transformed into the uniform carbon layer after calcination. • LiFePO{sub 4}/C nanoplates have good high-rate and low-temperature performance.

  20. Fabrication of highly uniform gel coatings by the conversion of surface-anchored metal-organic frameworks.

    Tsotsalas, Manuel; Liu, Jinxuan; Tettmann, Beatrix; Grosjean, Sylvain; Shahnas, Artak; Wang, Zhengbang; Azucena, Carlos; Addicoat, Matthew; Heine, Thomas; Lahann, Joerg; Overhage, Jörg; Bräse, Stefan; Gliemann, Hartmut; Wöll, Christof

    2014-01-08

    We report the fabrication of 3D, highly porous, covalently bound polymer films of homogeneous thickness. These surface-bound gels combine the advantages of metal-organic framework (MOF) materials, namely, the enormous flexibility and the large size of the maximum pore structures and, in particular, the possibility to grow them epitaxially on modified substrates, with those of covalently connected gel materials, namely, the absence of metal ions in the deposited material, a robust framework consisting of covalent bonds, and, most importantly, pronounced stability under biological conditions. The conversion of a SURMOF (surface-mounted MOF) yields a surface-grafted gel. These SURGELs can be loaded with bioactive compounds and applied as bioactive coatings and provide a drug-release platform in in vitro cell culture studies.

  1. TREATMENT OF METALS, POLYMER FILMS, AND FABRICS WITH A ONE ATMOSPHERE UNIFORM GLOW DISCHARGE PLASMA (OAUGDP) FOR INCREASED SURFACE ENERGY AND DIRECTIONAL ETCHING

    J. Reece Roth; Z.Y. Chen; Peter P.- Y. Tsai

    2001-01-01

    Direct exposure of samples to the active species of air generated by a One AtmosphereUniform Glow Discharge Plasma (OA UGDP) has been used to etch and to increasethe surface energy of metallic surfaces, photoresist, polymer films, and nonwoven fab-rics. The OAUGDP is a non-thermal plasma with the classical characteristics of aDC normal glow discharge that operates in air (and other gases) at atmospheric pres-sure. Neither a vacuum system nor batch processing is necessary. A wide range ofapplications to metals, photoresist, films, fabrics, and polymeric webs can be accom-modated by direct exposure of the workpiece to the plasma in parallel-plate reactors.This technology is simple, it produces effects that can be obtained in no other way atone atmosphere; it generates minimal pollutants or unwanted by-products; and it issuitable for individual sample or online treatment of metallic surfaces, wafers, films.and fabrics.``Early exposures of solid materials to the OA UGDP required minutes to produce rela-tively small increases of surface energy. These durations appeared too long for com-mercial application to fast-moving webs. Recent improvements in OA UGDP gas com-position, power density, plasma quality, recirculating gas flow, and impedance match-ing of the power supply to the parallel plate plasma reactor have made it possible toraise the surface energy ofa variety of polymeric webs (PP, PET, PE, etc.) to levels of60 to 70 dynes/crn with one second of exposure. In air plasmas, the high surface ener-gies are not durable, and fall to 50 dynes/em after periods of weeks to months. Here.we report the exposure of metallic surfaces, photoresist, polymeric films, and nonwo-ven fabrics made of PP and PET to an impedance matched parallel plate OA UGDPfor durations ranging from one second to several tens of seconds. Data will be re-ported on the surface energy, wettability, wickability, and aging effect of polymericfilms and fabrics as functions of time of exposure, and time

  2. Anderson AFB, Agana, Guam. revised uniform summary of surface weather observations (RUSSWO). parts a-f. Final report

    1978-08-31

    This report is a six-part statistical summary of surface weather observations for Anderson AFB, Agana, Guam. 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.

  3. Langley AFB, Newport News, Virginia. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    1979-06-01

    i1 1 "+ ’I"+ " *+ +" ENVI-77E 74 4, +, + ~ P CATON C UTER +"+,, :+ PARTO SURFACE WINDS , jr..,+ + -, + +"C reenedi tispatar vriu ta.ltins...frequency distribution of wet-bulb ) depression in 17 classes spread ho izontally; by 2-degree intervals of dry-bulb temperature spread vertically ...humidity and total number of observations in two tables. a. Table 1 is prepared by month and annual, all years combined, with montb being the vertical

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

    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.

  5. Fort Campbell, Campbell AAF, Kentucky. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    1982-12-01

    R SERVICE/MAC PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) ,4671 FT CAMPRELL KY 73-81 "A-’ ALL WEATHtR. SPEED MAN...34., AFETAC SURFACE WINDS A2 EATHR SEV1CL/MAC PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 74f-71 FT CAMPRELL KY 73-81...SERVI11/mAC ’ 467 . FT CAMPRELL KY 73-31 Ju’. e PERCENTAGE FREQUENCY OF OCCURRENCE (FROM HOURLY OBSERVATIONS) VfSf bitT STAT JTE -ILES !Ci Nu, i I -o i > I

  6. ACHIEVING THRESHOLD BARRIER OF 1 nm ROUGHNESS VALUE OF SILICON SURFACE BY DIAMOND TURNING

    1998-01-01

    1 nm roughness value of silicon surface by diamond turning is obtained firstly and three novel techniques are proposed. The surface integrity is studied in detail by using atomic force microscope, scanning electron microscope, and stylus surface instrument. The diamond tool sharpness hasa considerable influence on the machined surface, therefore a novel technique-brightness modulation for measuring accurately the edge of the cutter is proposed. Mirror surfaces are assessed by another novel technique-a measure of their reflectivity. A third technique, single grit diamond machining is carried out. It supplies a experimental evidence for verifying the obtained high quality turned surfaces.

  7. McGuire AFB, New Jersey. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F.

    1983-07-20

    2000 78 gUSAFETAC MYMv 0 10 SIOL A), moowmm ofv’F.no m, N wN a - ,/ USAFrTAC 010-5 L J, P’t’O SIlQIS~ttl~t IOItt: c’,.,-- * . *1 GLOBAL CLIMATOLOGY... mm Aon oss O$S i = . ft PA " --- 5LrBAL CLIMATOLOGY BRANCH S AFETAC SURFACE WINDS AIR wEATHER SERVICE/MA" PERCENTAGE FREQUENCY OF WIND DIRECTION AND...FROM HOURLY OBSERVATIONS) ALL hLFAT Hr ClASS mm US?.) SPEED IA KITS) I- 4.6 7.0 1.16 17-21 22 - 27 2 - 33 34.40 41 -47 491.55 2t s6 WIND DIR. _ _ SPEED

  8. Kimpo-iap K-14, Seoul, Korea. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    1973-10-30

    31.4 8,0 37;5 2266 03.05 .1 5.4 .504 3 6.8 6.3 43o2 2279 C 06;0S .2 5.6 5o5 50.6 211, . eo 63.0 2265 S09-.1 .2 4 4, 11.5 2696 35.5 2263 12.1* .1 _0 .0 5.0...SURFACE WINDS AIR WEATHER SERVICE/MAC PERCENTAGE FREQUENCY OF WIND DIRECTION AND SPEED (FROM HOURLY OBSERVATIONS) 4 3 2 n l K IM PJ IA P K ORFA / S EO U...OBSERVATIONS) 412n1 KtMPfl TAP KOR9A/SFDUL K-14 46,4050;71 qgp *TATK 4 StATION NAM& VIAS MONTH ALL W ATHER 12n.-14no CLASS HOURS IL.S.T.) ( CONDITION SPEED

  9. Don Muang IAP, Bangkok, Thailand. Revised Uniform Summary of Surface Weather Observations (RUSSWO). Parts A-F

    1971-04-02

    00,10 10. 0.09, M0.±0.1k., 0..D.’ 0 J AQf 100 98,4100, 00.0100. 100.01001 00. 100,0100,0100, 100.0 00,0 00,o000.0100.0 2: 0 so .00100 1 100,1000 20...SUMMARYOP SURFACE WEATHER OSEAYATM BANGKOK THAILAND/DON WUANG IAP W8ANO 41001 N 13 55 E 100 36 ELEV 33 FT VTOD WMOE 46436 PARTS A-F POR FROM HOURLY OBS JAN...LOCATION STION FROM TO STATIONIrr) BAROMETER DAY 0I Don uang Apt, Thailand /TAF Jan 54 Dee 63 N 13 55 E 100 36 33 39 Ft 24 LOCATION CHANACTEI LOCATION

  10. Natural convection flow of a nano-fluid over a vertical plate with uniform surface heat flux

    Khan, W.A. [Department of Engineering Sciences, National University of Sciences and Technology, Karachi 75350 (Pakistan); Aziz, A. [Department of Mechanical Engineering, School of Engineering and Applied Science, Gonzaga University, Spokane, WA 99258 (United States)

    2011-07-15

    Natural convective flow of a nano-fluid over a vertical plate with a constant surface heat flux is investigated numerically, following a similarity analysis of the transport equations. The transport model employed includes the effect of Brownian motion and thermophoresis. The analysis shows that velocity, temperature and concentration profiles in the respective boundary layers depend, besides the Prandtl and Lewis numbers, on three additional dimensionless parameters, namely a Brownian motion parameter Nb, a thermophoresis parameter Nt, a buoyancy ratio parameter Nr. In addition to the study of these parameters on the boundary layer flow characteristics (velocity, temperature, nano-particle concentration, skin friction, and heat transfer), correlations for the Nusselt and Sherwood numbers have been developed based on a regression analysis of the data. These correlations predict the numerical results with a maximum error of 5.5% for the reduced Nusselt number and 3.2% for the reduced Sherwood number. (authors)

  11. Exploiting the flexibility and the polarization of ferroelectric perovskite surfaces to achieve efficient photochemistry and enantiospecificity

    Rappe, Andrew [Univ. of Pennsylvania, Philadelphia, PA (United States)

    2017-01-06

    This research project explored the catalytic properties of complex surfaces of functional materials. The PI used first-principles density functional theory (DFT) calculations to explore a tightly integrated set of properties. The physical properties of complex functional materials that influence surface chemistry were explored, including bulk and surface electric dipoles, and surface conductivity. The energetic, compositional, electronic, and chemical properties of the surfaces of these materials were explored in detail, and connections between material properties and chemical reactivity were established. This project led to 28 publications, including Nat. Comm., JACS, 3 PRL, 7 PRB, 2 ACS Nano, 2 Nano Lett., 4 JPCL, 2 JCP, Chem. Mater., ACS Appl. Mater. Interfaces, Phys. Rev. Appl., and a U.S. Patent on surface catalysts. The key accomplishments in this project involved work in six coordinated areas: pioneering ways to control bulk dipoles in order to dynamically affect catalysis, exploring novel ways of bringing charge to the surface for redox catalysis, nonstoichiometric surfaces offering new sites for heterogeneous catalysis, illustrating how surface catalysis responds to applied pressure, catalytic growth of carbon-based materials, and new computational methods allowing more accurate exploration of molecule-surface interactions

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

    Sun D

    2016-06-01

    Full Text Available Deqing Sun,1,2 Aiying Xue,3 Bin Zhang,1 Xia Xue,1 Jie Zhang,1 Wenjie Liu1 1Department of Pharmacy, the Second Hospital of Shandong University, Jinan, People’s Republic of China; 2School of Pharmaceutical Sciences, Shandong University, Jinan, People’s Republic of China; 3Department of Cardiology, the Second Hospital of Shandong University, Jinan, People’s Republic of China Abstract: 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. Keywords: acetylpuerarin, nanoparticles, poly(lactic-co-glycolic acid, pharmacokinetics, bioavailability

  13. Achieving tunable surface tension in the pseudopotential lattice Boltzmann modeling of interface dynamics

    Li, Q

    2013-01-01

    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 multi-range potential was devised to adjust the surface tension [Sbragaglia et al., Phys. Rev. E, 2007, 75, 026702; Sbragaglia et al. Soft Matter, 2012, 8, 10773]. However, this approach was found to be unable to keep the density ratio unchanged when the surface tension is adjusted. An alternative approach is therefore proposed in the present work. The basic strategy is to add a new 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 c...

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

    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.

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

    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.

  16. Achieving clean epitaxial graphene surfaces suitable for device applications by improved lithographic process

    Nath, A., E-mail: anath@gmu.edu; Rao, M. V. [George Mason University, 4400 University Dr., Fairfax, Virginia 22030 (United States); Koehler, A. D.; Jernigan, G. G.; Wheeler, V. D.; Hite, J. K.; Hernández, S. C.; Robinson, Z. R.; Myers-Ward, R. L.; Eddy, C. R.; Gaskill, D. K. [U.S. Naval Research Laboratory, 4555 Overlook Ave. SW, Washington, D.C. 20375 (United States); Garces, N. Y. [Sotera Defense Solutions, 2200 Defense Hwy. Suite 405, Crofton, Maryland 21114 (United States)

    2014-06-02

    It is well-known that the performance of graphene electronic devices is often limited by extrinsic scattering related to resist residue from transfer, lithography, and other processes. Here, we report a polymer-assisted fabrication procedure that produces a clean graphene surface following device fabrication by a standard lithography process. The effectiveness of this improved lithography process is demonstrated by examining the temperature dependence of epitaxial graphene-metal contact resistance using the transfer length method for Ti/Au (10 nm/50 nm) metallization. The Landauer-Buttiker model was used to explain carrier transport at the graphene-metal interface as a function of temperature. At room temperature, a contact resistance of 140 Ω-μm was obtained after a thermal anneal at 523 K for 2 hr under vacuum, which is comparable to state-of-the-art values.

  17. A thin rivulet or ridge subject to a uniform transverse shear stress at its free surface due to an external airflow

    Sullivan, J. M.

    2012-01-01

    We use the lubrication approximation to analyze three closely related problems involving a thin rivulet or ridge (i.e., a two-dimensional droplet) of fluid subject to a prescribed uniform transverse shear stress at its free surface due to an external airflow, namely a rivulet draining under gravity down a vertical substrate, a rivulet driven by a longitudinal shear stress at its free surface, and a ridge on a horizontal substrate, and find qualitatively similar behaviour for all three problems. We show that, in agreement with previous numerical studies, the free surface profile of an equilibrium rivulet/ridge with pinned contact lines is skewed as the shear stress is increased from zero, and that there is a maximum value of the shear stress beyond which no solution with prescribed semi-width is possible. In practice, one or both of the contact lines will de-pin before this maximum value of the shear stress is reached, and so we consider situations in which the rivulet/ridge de-pins at one or both contact lines. In the case of de-pinning only at the advancing contact line, the rivulet/ridge is flattened and widened as the shear stress is increased from its critical value, and there is a second maximum value of the shear stress beyond which no solution with a prescribed advancing contact angle is possible. In contrast, in the case of de-pinning only at the receding contact line, the rivulet/ridge is thickened and narrowed as the shear stress is increased from its critical value, and there is a solution with a prescribed receding contact angle for all values of the shear stress. In general, in the case of de-pinning at both contact lines there is a critical "yield" value of the shear stress beyond which no equilibrium solution is possible and the rivulet/ridge will evolve unsteadily. In the Appendix, we show that an equilibrium rivulet/ridge with prescribed flux/area is quasi-statically stable to two-dimensional perturbations. © 2012 American Institute of Physics.

  18. Sea Surface Scattering Image Defogging Algorithm Based on Uniformly Ergodic Texture Addressing%均匀遍历纹理寻址的水面散射图像去雾算法

    刘岩

    2015-01-01

    提出一种基于均匀遍历纹理寻址的水面散射图像去雾算法,构建水面大气散射物理模型,把图像分成天空区域、海面区域和海天交界线区域等三个区域,对海天交界线是海面和天空区域的交界线进行提取,采用Canny边缘检测和Hough直线检测相结合,得到图像的边缘提取结果。采用均匀遍历纹理寻址的方法,计算各直线段的长度找出最长的线段就是海天线,实现对图像场景的恢复,实现图像去雾清晰化处理。仿真结果表明,该算法去雾效果较好,对于海面浓雾的去雾处理效果明显。研究成果将在复杂天气下成像目标识别等领域具有很好的工程应用价值。%Sea surface scattering image defogging algorithm is proposed based on uniformly ergodic texture addressing, the image is divided into three regions, the sea sky region area and boundary region of Haitian, Haitian demarcation line is the sea and the sky region boundary extraction, using Canny edge detection and Hough line detection the combination, obtain image edge extraction results are obtained. By using the method of uniformly ergodic texture addressing calculations to iden⁃tify segments, the longest is the sea sky line each line segment length, the realization of the image scene recovery, to achieve image defogging clear processing. The simulation results show that, the algorithm defogging effect is good, the sea fog to mist treatment effect is obvious. The research results will have good application value in target recognition under com⁃plex weather.

  19. The Uniform Rugosity Effect

    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.

  20. Quasi-uniform Space

    Coghetto Roland

    2016-09-01

    Full Text Available In this article, using mostly Pervin [9], Kunzi [6], [8], [7], Williams [11] and Bourbaki [3] works, we formalize in Mizar [2] the notions of quasiuniform space, semi-uniform space and locally uniform space.

  1. Do School Uniforms Fit?

    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)

  2. School Uniforms Redux.

    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…

  3. School Uniform Policies in Public Schools

    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. 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

    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

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

    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.

  6. Uniform surface modification of 3D Bioglass®-based scaffolds with mesoporous silica particles (MCM-41 for enhancing drug uptake capability

    Elena eBoccardi

    2015-11-01

    Full Text Available 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 is 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 at the same time 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.

  7. A highly efficient surface plasmon polaritons excitation achieved with a metal-coupled metal-insulator-metal waveguide

    Hongyan Yang

    2014-12-01

    Full Text Available We propose a novel metal-coupled metal-insulator-metal (MC-MIM waveguide which can achieve a highly efficient surface plasmon polaritons (SPPs excitation. The MC-MIM waveguide is formed by inserting a thin metal film in the insulator of an MIM. The introduction of the metal film, functioning as an SPPs coupler, provides a space for the interaction between SPPs and a confined electromagnetic field of the intermediate metal surface, which makes energy change and phase transfer in the metal-dielectric interface, due to the joint action of incomplete electrostatic shielding effect and SPPs coupling. Impacts of the metal film with different materials and various thickness on SPPs excitation are investigated. It is shown that the highest efficient SPPs excitation is obtained when the gold film thickness is 60 nm. The effect of refractive index of upper and lower symmetric dielectric layer on SPPs excitation is also discussed. The result shows that the decay value of refractive index is 0.3. Our results indicate that this proposed MC-MIM waveguide may offer great potential in designing a new SPPs source.

  8. Two-dimensional deformation of a uniform half-space due to non-uniform movement accompanying a long vertical tensile fracture

    Sunita Rani; Ram Chander Verma

    2013-08-01

    The solution of the static deformation of a homogeneous, isotropic, perfectly elastic half-space caused by uniform movement along a long vertical tensile fracture is well known. In this paper, we study the problem of static deformation of a homogeneous, isotropic, perfectly elastic half-space caused by a nonuniform movement along a long vertical tensile fracture of infinite length and finite depth. Four movement profiles are considered: linear, parabolic, elliptic and cubic. The deformation corresponding to the four non-uniform movement profiles is compared numerically with the deformation due to a uniform case, assuming the source potency to be the same. The equality in source potency is achieved in two ways: One, by varying the depth of fracture and keeping the surface discontinuity constant and the other way, by keeping the depth of fracture constant and varying the surface discontinuity. It is found that the effect of non-uniformity in movement in the near field is noteworthy. The far field is not affected significantly by the non-uniformity in movement. In the first case, horizontal displacement is significantly affected rather than vertical displacement. In the second case, non-uniformity in movement changes the magnitude of the displacement at the surface. Also, the displacements around a long vertical tensile fracture for different movement profiles are plotted in three dimensions.

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

    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.

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

    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.

  11. A method for achieving monotonic frequency-temperature response for langasite surface-acoustic-wave high-temperature sensor

    Shaoming, Bao; Yabing, Ke; Yanqing, Zheng; Lina, Cheng; Honglang, Li

    2016-02-01

    To achieve the monotonic frequency-temperature response for a high-temperature langasite (LGS) surface-acoustic-wave (SAW) sensor in a wide temperature range, a method utilizing two substrate cuts with different propagation angles on the same substrate plane was proposed. In this method, the theory of effective permittivity is adopted to calculate the temperature coefficients of frequency (TCF), electromechanical coupling coefficients (k2), and power flow angle (PFA) for different propagation angles on the same substrate plane, and then the two substrate cuts were chosen to have large k2 and small PFA, as well as the difference in their TCFs (ΔTCF) to always have the same sign of their values. The Z-cut LGS substrate plane was taken as an example, and the two suitable substrate cuts with propagation angles of 74 and 80° were chosen to derive a monotonic frequency-temperature response for LGS SAW sensors at -50 to 540 °C. Experiments on a LGS SAW sensor using the above two substrate cuts were designed, and its measured frequency-temperature response at -50 to 540 °C agreed well with the theory, demonstrating the high accuracy of the proposed method.

  12. 自由曲线曲面的任意次非均匀细分%Non-uniform subdivision approach for free-form curves and surfaces of arbitrary degree

    郑辑涛; 秦开怀

    2011-01-01

    提出一种有效的建模自由曲线曲面的非均匀细分算法.首先在节点插入技术基础上推导出任意次自由曲线的非均匀细分规则,然后把它推广到张量积曲面得到任意次自由曲面的非均匀细分规则,最后对奇异点附近曲面采用类Doo-Sabin和Catmull-Clark的细分规则,从而使该算法可以实现建模任意次具有任意拓扑基网格的非均匀细分曲面.此外,该方法也实现了对传统细分格式的统一,例如,当次数为2并采用均匀节点矢量便转化为Doo-Sabin细分,当次数为3并采用均匀节点矢量便转化为Catmull-Clark细分.%In this paper, a new recursive non-uniform subdivision approach for modeling free-form curves and surfaces was presented. Based on the knot insertion technique, the non-uniform subdivision rules were provided for modeling arbitrarydegree curves and surfaces of arbitrary topology with non-uniform knot intervals. In particular, this approach generalized the traditional uniform subdivisions, such as Doo-Sabin and Catmull-Clark subdivision.

  13. A practical technique for the generation of highly uniform LIPSS

    Ardron, Marcus, E-mail: ma745@hw.ac.uk [School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh EH14 4AS (United Kingdom); Renishaw PLC, Research Avenue North, Riccarton, Edinburgh EH14 4AP (United Kingdom); Weston, Nick [Renishaw PLC, Research Avenue North, Riccarton, Edinburgh EH14 4AP (United Kingdom); Hand, Duncan [School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh EH14 4AS (United Kingdom)

    2014-09-15

    Highlights: • Formation of uniform LIPSS on stainless steel is greatly aided by polishing in an orthogonal direction to the expected periodic features. Roughness of a sample surface must avoid vector spatial frequency content near to that of the expected LIPSS. • A very simple polishing technique was found to be suitable. • Surface finish requirement was predicted based on the efficacy factor theory; one of the few theories to give qualitatively strong agreement with experimental evidence in a field that is not fully explained by current theories. • Modelled and experimental results presented. • Using a line focused beam from an ultrafast laser facilitated the rapid production of relatively large areas of LIPSS with a modest laser repetition rate. - Abstract: Laser-induced periodic surface structures (LIPSS) can be reliably produced with ultrashort (<10 ps) laser pulses given fluence near the ablation threshold. Neat, parallel, uniform structures are harder to reproduce. Electrodynamic models show a field at normal incidence interacts with the surface resulting in periodicity in intensity along the surface in the direction of the incident E-field producing ridges and toughs on the surface orthogonal to the E-field. A completely smooth surface offers nothing to perturb the eventual periodic feature formation but is very difficult to achieve: we have demonstrated that simply avoiding surface roughness components near the frequency and direction of the emergent features significantly improves uniform feature production. An appropriate unidirectional polishing process can be realised using an inexpensive spinning cloth wheel. By using a cylindrical lens we were also able to process stainless steel surfaces at 5 mm{sup 2} s{sup −1} so indicating useful industrial potential.

  14. Games Uniforms Unveiled

    Linda

    2008-01-01

    The uniforms for Beijing Olympics’ workers, technical staff and volunteers have been unveiled to mark the 200-day countdown to the Games. The uniforms feature the key element of the clouds of promise and will be in three colors:red for Beijing Olympic Games Committee staff, blue

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

    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.

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

    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.

  17. Layered Non-uniform Node Distribution Strategy to Achieve Energy Consumption Balance%分层式非均匀节点布置的能耗均衡策略

    凌强; 袁俊杰; 严金丰

    2013-01-01

    In wireless sensor networks, sensor nodes need to send data to the sink node. Due to the communication distance limitation, the sensor nodes being far from the sink node cannot directly send their data to the sink node and need other nodes to relay their data to the sink node. The nodes near the sink node have to spend much energy to relay the data from the far nodes, and will die faster. When the near nodes all die, no data can be received by the sink node and the network stops working, which is referred to as energy hole. We propose a new layered non-uniform strategy to distribute the sensor nodes in a network, which increases the inner node density in order to avoid energy hole and can greatly improve the efficiency of the energy consumption. This strategy is simulated on an NS2 platform. Simulation results confirms that this strategy is effective and can significantly improve the energy consumption balance.%无线传感器网络中,大量的传感器节点检测的数据需要转发给基站.但是由于节点本身能量十分有限,有时需要多次转发才能到达基站.由于转发机制的存在,在基站附近的节点除了转发本身检测的数据外,还要大量转发远离基站的外层节点的数据,这使得基站附近节点负载过重而提前死亡,导致基站附近形成”能量洞”,最终导致网络死亡.针对这个问题,提出一种新的非均匀节点布置策略:调整网络的节点密度布置结构、增加内层节点的密度以分担内层节点负载,从而避免”能量洞”,提高网络的能量利用率.本文的策略通过NS2仿真平台加以实现.仿真结果表明本策略针对”能量洞”问题是有效的、能够有效提高网络的能耗均衡性.

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

    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.

  19. 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

    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.

  20. 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

    Ming-Hui Li

    2017-01-01

    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.

  1. Uniformly Convex Metric Spaces

    Kell Martin

    2014-01-01

    In this paper the theory of uniformly convex metric spaces is developed. These spaces exhibit a generalized convexity of the metric from a fixed point. Using a (nearly) uniform convexity property a simple proof of reflexivity is presented and a weak topology of such spaces is analyzed. This topology called co-convex topology agrees with the usualy weak topology in Banach spaces. An example of a $CAT(0)$-spaces with weak topology which is not Hausdorff is given. This answers questions raised b...

  2. Synthesis and surface modification of uniform MFe{sub 2}O{sub 4} (M = Fe, Mn, and Co) nanoparticles with tunable sizes and functionalities

    Cabrera, Lourdes I., E-mail: lourisa_cabrera@yahoo.com [Universita degli Studi di Firenze, LA.M.M. c/o dipartimento di Chimica (Italy); Somoza, Alvaro [Faculty of Science Module C-IX, Instituto Madrileno de Estudios Avanzados-Nanociencia (Spain); Marco, Jose F. [Instituto de Quimica-Fisica ' ROCASOLANO' , CSIC (Spain); Serna, Carlos J.; Puerto Morales, M. [Instituto de Ciencia de Materiales de Madrid, CSIC (Spain)

    2012-06-15

    Cubic monodisperse MFe{sub 2}O{sub 4} 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.

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

    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.

  4. High-voltage electrode optimization towards uniform surfacetreatment by a pulsed volume discharge

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

    2015-01-01

    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 r...

  5. Uniform random number generators

    Farr, W. R.

    1971-01-01

    Methods are presented for the generation of random numbers with uniform and normal distributions. Subprogram listings of Fortran generators for the Univac 1108, SDS 930, and CDC 3200 digital computers are also included. The generators are of the mixed multiplicative type, and the mathematical method employed is that of Marsaglia and Bray.

  6. Synthesis of uniform and size-controllable carbon nanospheres by a simple hydrothermal method and fabrication of carbon nanosphere super-hydrophobic surface

    Joula, Mohsen Heidari; Farbod, Mansoor, E-mail: farbod_m@scu.ac.ir

    2015-08-30

    Highlights: • A simple hydrothermal method was used to produce carbon nanospheres (CNSs). • The size of CNSs was controlled by the concentration of initial sucrose solution. • The size of CNSs was reduced to 100 nm by post-annealing of the CNSs. • A glass substrate was coated with CNSs thick film using spin coating method. • Contact angle of a water droplet was 153° indicating the film is super-hydrophobic. - Abstract: A simple hydrothermal method was used to produce high yield, monodisperse and tightly controllable size of carbon nanospheres (CNSs) by adjusting the concentration of initial sucrose solution in a sealed autoclave at 170 °C for 8 h. By changing the solution concentration from 0.5 to 0.1 mol l{sup −1}, the sizes of carbon spheres (CS) were reduced from about 2500 to about 300 nm. Also by increasing the solution volume to the vessel volume ratio (V{sub s}/V{sub v}) from 5/6 to 11/13, the yield of CS was increased from 25% up to about 55% of initial raw materials. It was found that by post-annealing of the 300 nm CNSs at 435 °C for 30 min, their diameters were reduced to 100 nm. Moreover, annealing in air atmosphere had a noticeable influence on the surface functional groups and bonds of CNSs. In addition, CNSs were used to fabricate hydrophobic surfaces by coating their ethanolic colloidal solution on glass substrates. The measured contact angle (CA) of a water droplet was about 153°, indicating that the CNSs thick layers were super-hydrophobic. The size dependence of CNSs on the different parameters has been discussed.

  7. Surface Treatment of 45S5 Bio-glass using Femtosecond Laser to Achieve Superior Growth of Hydroxyapatite

    Shaikh, Shazia; Singh, Anil Kumar; Sharma, Kuldeep; Sinha, Sucharita

    2016-01-01

    45S5 Hench bio-glass (BG) has gained interest in research because of its potential clinical applications. Several studies in-vivo and in-vitro have been in progress to improve bio-integration efficiency of this glass. In present contribution, surface modification of Hench BG has been done employing a femtosecond (fs) laser beam, resulting in increased effective surface area of the sample. These surface modified samples were subsequently immersed in simulated body fluid for varying number of days and characterized using Scanning electron microscope, energy dispersive X-ray analysis, X-ray diffraction, and micro-Raman spectroscopy. In-vitro studies indicated superior growth of hydroxyapatite (HAP) layer on the laser treated samples in comparison to the untreated samples. Presence of strong XRD peaks confirmed faster growth of HAP on laser treated samples. Raman peaks, five times more intense and relatively narrower represented higher crystallinity of hydroxyapatite layer on laser treated BG.

  8. Negotiating Surface Water Allocations to Achieve a Soft Landing in the Closed Lerma-Chapala Basin, Mexico

    Wester, P.; Vargas-Velázquez, S.; Mollard, E.; Silva-Ochoa, P.

    2008-01-01

    The Lerma-Chapala basin exemplifies the challenges posed by basin closure, where surface water allocation mechanisms, lack of environmental flows and access to water are critical issues. Underlying these issues is a need for accurate water accounting that is transparent and publicly available. This

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

    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.

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

    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.

  11. Uniform Refraction in Negative Refractive Index Materials

    Gutierrez, Cristian E

    2015-01-01

    We study the problem of constructing an optical surface separating two homogeneous, isotropic media, one of which has a negative refractive index. In doing so, we develop a vector form of Snell's law, which is used to study surfaces possessing a certain uniform refraction property, both in the near and far field cases. In the near field problem, unlike the case when both materials have positive refractive index, we show that the resulting surfaces can be neither convex nor concave.

  12. Uniform refraction in negative refractive index materials.

    Gutiérrez, Cristian E; Stachura, Eric

    2015-11-01

    We study the problem of constructing an optical surface separating two homogeneous, isotropic media, one of which has a negative refractive index. In doing so, we develop a vector form of Snell's law, which is used to study surfaces possessing a certain uniform refraction property, in both the near- and far-field cases. In the near-field problem, unlike the case when both materials have positive refractive indices, we show that the resulting surfaces can be neither convex nor concave.

  13. Uniform Requirements for Manuscripts

    2011-01-01

    @@ Introduction The Uniform requirements are instructions to authors on how to prepare manuscripts.If authors prepare their manuscripts in the style specified in these requirements, editors of the participating journals will not return the manuscripts for changes in style before considering them for publication.In the publishing process, however, the journals may alter accepted manuscripts to conform with details of their publication styles.

  14. Packaging Glass with a Hierarchically Nanostructured Surface: A Universal Method to Achieve Self-Cleaning Omnidirectional Solar Cells

    Lin, Chin An

    2015-12-01

    Fused-silica packaging glass fabricated with a hierarchical structure by integrating small (ultrathin nanorods) and large (honeycomb nanowalls) structures was demonstrated with exceptional light-harvesting solar performance, which is attributed to the subwavelength feature of the nanorods and an efficient scattering ability of the honeycomb nanowalls. Si solar cells covered with the hierarchically structured packaging glass exhibit enhanced conversion efficiency by 5.2% at normal incidence, and the enhancement went up to 46% at the incident angle of 60°. The hierarchical structured packaging glass shows excellent self-cleaning characteristics: 98.8% of the efficiency is maintained after 6 weeks of outdoor exposure, indicating that the nanostructured surface effectively repels polluting dust/particles. The presented self-cleaning omnidirectional light-harvesting design using the hierarchical structured packaging glass is a potential universal scheme for practical solar applications.

  15. Fabricating a Homogeneously Alloyed AuAg Shell on Au Nanorods to Achieve Strong, Stable, and Tunable Surface Plasmon Resonances

    Huang, Jianfeng

    2015-08-13

    Colloidal metal nanocrystals with strong, stable, and tunable localized surface plasmon resonances (SPRs) can be useful in a corrosive environment for many applications including field-enhanced spectroscopies, plasmon-mediated catalysis, etc. Here, a new synthetic strategy is reported that enables the epitaxial growth of a homogeneously alloyed AuAg shell on Au nanorod seeds, circumventing the phase segregation of Au and Ag encountered in conventional synthesis. The resulting core–shell structured bimetallic nanorods (AuNR@AuAg) have well-mixed Au and Ag atoms in their shell without discernible domains. This degree of mixing allows AuNR@AuAg to combine the high stability of Au with the superior plasmonic activity of Ag, thus outperforming seemingly similar nanostructures with monometallic shells (e.g., Ag-coated Au NRs (AuNR@Ag) and Au-coated Au NRs (AuNR@Au)). AuNR@AuAg is comparable to AuNR@Ag in plasmonic activity, but that it is markedly more stable toward oxidative treatment. Specifically, AuNR@AuAg and AuNR@Ag exhibit similarly strong signals in surface-enhanced Raman spectroscopy that are some 30-fold higher than that of AuNR@Au. When incubated with a H2O2 solution (0.5 m), the plasmonic activity of AuNR@Ag immediately and severely decayed, whereas AuNR@AuAg retained its activity intact. Moreover, the longitudinal SPR frequency of AuNR@AuAg can be tuned throughout the red wavelengths (≈620–690 nm) by controlling the thickness of the AuAg alloy shell. The synthetic strategy is versatile to fabricate AuAg alloyed shells on different shaped Au, with prospects for new possibilities in the synthesis and application of plasmonic nanocrystals.

  16. Uniform gradient expansions

    Giovannini, Massimo, E-mail: massimo.giovannini@cern.ch [Department of Physics, Theory Division, CERN, 1211 Geneva 23 (Switzerland); INFN, Section of Milan-Bicocca, 20126 Milan (Italy)

    2015-06-30

    Cosmological singularities are often discussed by means of a gradient expansion that can also describe, during a quasi-de Sitter phase, the progressive suppression of curvature inhomogeneities. While the inflationary event horizon is being formed the two mentioned regimes coexist and a uniform expansion can be conceived and applied to the evolution of spatial gradients across the protoinflationary boundary. It is argued that conventional arguments addressing the preinflationary initial conditions are necessary but generally not sufficient to guarantee a homogeneous onset of the conventional inflationary stage.

  17. Collocation on uniform grids

    Amore, Paolo; Saenz, Ricardo A; Salvo, Koen [Facultad de Ciencias, CUICBAS, Universidad de Colima, Bernal DIaz del Castillo 340 Colima, Colima (Mexico); Fernandez, Francisco M [INIFTA (UNLP, CCT La Plata-Conicet), Diag. 113 y 64 S/N, Sucursal 4, Casilla de Correo 16, 1900 La Plata (Argentina)], E-mail: paolo.amore@gmail.com, E-mail: fernande@quimica.unlp.edu.ar, E-mail: rasaenz@ucol.mx, E-mail: koen.salvo@gmail.com

    2009-03-20

    In this paper we derive four sets of sinc-like functions, defined on a finite interval and obeying different boundary conditions. The functions in each set are orthogonal and their nodes are uniformly distributed on the interval. We have applied each set to solve a large class of eigenvalue equations, with different boundary conditions, both on finite intervals and on the real line, showing that precise numerical results can be obtained efficiently and rapidly. A comparison with results available in the literature is also performed.

  18. Uniform distribution of sequences

    Kuipers, L

    2006-01-01

    The theory of uniform distribution began with Hermann Weyl's celebrated paper of 1916. In later decades, the theory moved beyond its roots in diophantine approximations to provide common ground for topics as diverse as number theory, probability theory, functional analysis, and topological algebra. This book summarizes the theory's development from its beginnings to the mid-1970s, with comprehensive coverage of both methods and their underlying principles.A practical introduction for students of number theory and analysis as well as a reference for researchers in the field, this book covers un

  19. The uniform electron gas

    Loos, Pierre-François

    2016-01-01

    The uniform electron gas or UEG (also known as jellium) is one of the most fundamental models in condensed-matter physics and the cornerstone of the most popular approximation --- the local-density approximation --- within density-functional theory. In this article, we provide a detailed review on the energetics of the UEG at high, intermediate and low densities, and in one, two and three dimensions. We also report the best quantum Monte Carlo and symmetry-broken Hartree-Fock calculations available in the literature for the UEG and discuss the phase diagrams of jellium.

  20. Uniform gradient expansions

    Massimo Giovannini

    2015-06-01

    Full Text Available Cosmological singularities are often discussed by means of a gradient expansion that can also describe, during a quasi-de Sitter phase, the progressive suppression of curvature inhomogeneities. While the inflationary event horizon is being formed the two mentioned regimes coexist and a uniform expansion can be conceived and applied to the evolution of spatial gradients across the protoinflationary boundary. It is argued that conventional arguments addressing the preinflationary initial conditions are necessary but generally not sufficient to guarantee a homogeneous onset of the conventional inflationary stage.

  1. Women in service uniforms

    Hanna Karaszewska

    2012-12-01

    Full Text Available The article discusses the problems of women who work in the uniformed services with the particular emphasis on the performing of the occupation of the prison service. It presents the legal issues relating to equal treatment of men and women in the workplace, formal factors influencing their employment, the status of women in prison, and the problems of their conducting in the professional role. The article also presents the results of research conducted in Poland and all over the world, on the functioning of women in prison and their relations with officers of the Prison Service, as well as with inmates.

  2. Should School Nurses Wear Uniforms?

    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…

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

    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. Bi-cubic non-uniform B-spline surface reconstruction for slice contours%断层轮廓的双三次非均匀B样条曲面重构

    王瑜; 郑津津; 周洪军; 沈连婠

    2011-01-01

    A surface reconstruction method from the slice contours was proposed. First, feature points were extracted based on curvature feature, and they were resampled in order to get a unification of sampling points in each line (column). Then, the sampling points were interpolated to get a bi-cubic non-uniform B-spline surface. Finally, nodes were inserted on the surface based on distance feature at a certain control accuracy, and the new control points through the least-squares approximation method were calculated to get approximate surface within the permissible range error. Based on the characteristics of slice contours, B-spline cycle and non-cycle B-spline combined, and the calculation of closed and non-closed surface was discussed. It was found that the combination of interpolation and approximation makes the algorithm more rapid and practical.%针对断层图像数据,提出了一种曲面重构的方法.依据曲率特征首先提取各层特征点,对其重采样使每行(列)获得统一的采样点数;再对采样点插值得到非均匀双三次B样条曲面;最后,在一定控制精度下对曲面依据距离特征进行节点插入,通过最小二乘逼近法算出新的控制顶点,从而得到误差在容许范围内的逼近曲面.根据断层轮廓的特点,本算法综合运用了周期B样条和非周期B样条,讨论了封闭曲面和非封闭曲面的计算方法.另外插值和逼近的结合应用使该算法更快速、实用.

  5. Uniform Stability of Damped Nonlinear Vibrations of an Elastic String

    Ganesh C Gorain; Sujit K Bose

    2003-11-01

    Here we are concerned about uniform stability of damped nonlinear transverse vibrations of an elastic string fixed at its two ends. The vibrations governed by nonlinear integro-differential equation of Kirchoff type, is shown to possess energy uniformly bounded by exponentially decaying function of time. The result is achieved by considering an energy-like Lyapunov functional for the system.

  6. Uniform quantized electron gas

    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.

  7. Uniformly rotating neutron stars

    Boshkayev, Kuantay

    2016-01-01

    In this chapter we review the recent results on the equilibrium configurations of static and uniformly rotating neutron stars within the Hartle formalism. We start from the Einstein-Maxwell-Thomas-Fermi equations formulated and extended by Belvedere et al. (2012, 2014). We demonstrate how to conduct numerical integration of these equations for different central densities ${\\it \\rho}_c$ and angular velocities $\\Omega$ and compute the static $M^{stat}$ and rotating $M^{rot}$ masses, polar $R_p$ and equatorial $R_{\\rm eq}$ radii, eccentricity $\\epsilon$, moment of inertia $I$, angular momentum $J$, as well as the quadrupole moment $Q$ of the rotating configurations. In order to fulfill the stability criteria of rotating neutron stars we take into considerations the Keplerian mass-shedding limit and the axisymmetric secular instability. Furthermore, we construct the novel mass-radius relations, calculate the maximum mass and minimum rotation periods (maximum frequencies) of neutron stars. Eventually, we compare a...

  8. Assessment indices for uniform and non-uniform thermal environments

    2008-01-01

    Different assessment indices for thermal environments were compared and selected for proper assessment of indoor thermal environments.30 subjects reported their overall thermal sensation,thermal comfort,and thermal acceptability in uniform and non-uniform conditions.The results show that these three assessment indices provide equivalent evaluations in uniform environments.However,overall thermal sensation differs from the other two indices and cannot be used as a proper index for the evaluation of non-uniform environments.The relationship between the percentage and the mean vote for each index is established.

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

    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.

  10. School Uniforms: Esprit de Corps.

    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,…

  11. Statistical Test for Bivariate Uniformity

    Zhenmin Chen

    2014-01-01

    Full Text Available The purpose of the multidimension uniformity test is to check whether the underlying probability distribution of a multidimensional population differs from the multidimensional uniform distribution. The multidimensional uniformity test has applications in various fields such as biology, astronomy, and computer science. Such a test, however, has received less attention in the literature compared with the univariate case. A new test statistic for checking multidimensional uniformity is proposed in this paper. Some important properties of the proposed test statistic are discussed. As a special case, the bivariate statistic test is discussed in detail in this paper. The Monte Carlo simulation is used to compare the power of the newly proposed test with the distance-to-boundary test, which is a recently published statistical test for multidimensional uniformity. It has been shown that the test proposed in this paper is more powerful than the distance-to-boundary test in some cases.

  12. Uniform Acceleration in General Relativity

    Friedman, Yaakov

    2016-01-01

    We extend de la Fuente and Romero's 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.

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

    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…

  14. Direction of Arrival Estimation Based on MUSIC Algorithm Using Uniform and Non-Uniform Linear Arrays

    Eva Kwizera

    2017-03-01

    Full Text Available In signal processing, the direction of arrival (DOA estimation denotes the direction from which a propagating wave arrives at a point, where a set of antennas is located. Using the array antenna has an advantage over the single antenna in achieving an improved performance by applying Multiple Signal Classification (MUSIC algorithm. This paper focuses on estimating the DOA using uniform linear array (ULA and non-uniform linear array (NLAof antennas to analyze the performance factors that affect the accuracy and resolution of the system based on MUSIC algorithm. The direction of arrival estimation is simulated on a MATLAB platform with a set of input parameters such as array elements, signal to noise ratio, number of snapshots and number of signal sources. An extensive simulation has been conducted and the results show that the NLA with DOA estimation for co-prime array can achieve an accurate and efficient DOA estimation

  15. Sckool Dress Rule, Uniform Policies

    潘志强

    2005-01-01

    Our schools believe that a uniform policy will provide a better environment, promote positive selfesteem, encourage an atmosphere for greater discipline, and increase learning opportunities for students by removing many of the distractions associated with various types of clothing.

  16. Uniform polyhedra: old and new

    Melikhov, Sergey A

    2011-01-01

    We develop a theory of metric polyhedra, including locally infinite dimensional ones. Motivated by algebraic topology, we focus on their uniform properties (i.e., those preserved by homeomorphisms that are uniformly continuous in both directions) but in doing so we also study their metric and Lipschitz properties. On the combinatorial side, (the face posets of) simplicial or cubical complexes do not suffice for this, and we have to rework some basic PL topology into a purely combinatorial machinery (with all homeomorphisms eliminated in favor of combinatorial isomorphisms) based on posets and their canonical subdivision (which is just the poset of all order intervals of the given poset, ordered by inclusion). Antecedents of this approach to PL topology are found in van Kampen's 1929 dissertation and in modern Topological Combinatorics. Our main results establish, in particular, close but troubled relations between uniform polyhedra and uniform ANRs, and appear to provide a satisfactory solution to an open-end...

  17. Highly Stable Silver Nanoplates for Surface Plasmon Resonance Biosensing

    Gao, Chuanbo [University of California, Riverside; Lu, Zhenda [University of California, Riverside; Chi, Miaofang [ORNL; Liu, ying [University of California, Riverside; Cheng, Quan [University of California, Riverside; Yin, Yadong [University of California, Riverside

    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.

  18. Achieving Standardization

    Henningsson, Stefan

    2016-01-01

    competitive, national customs and regional economic organizations are seeking to establish a standardized solution for digital reporting of customs data. However, standardization has proven hard to achieve in the socio-technical e-Customs solution. In this chapter, the authors identify and describe what has...

  19. Achieving Standardization

    Henningsson, Stefan

    2014-01-01

    competitive, national customs and regional economic organizations are seeking to establish a standardized solution for digital reporting of customs data. However, standardization has proven hard to achieve in the socio-technical e-Customs solution. In this chapter, the authors identify and describe what has...

  20. Landing the uniformly accelerating observers

    Rothenstein, Bernhard; Popescu, Stefan; Gruber, Ronald P.

    2006-01-01

    Observers of the uniformly accelerating observers or the observers who make up the system of uniformly accelerating observers reach the same velocity V at different times ti which depends on V and on theirs acceleration gi. Considering a platform that moves with constant velocity V, the observers can land smoothly on it. Their ages and locations in the inertial reference frame attached to the platform are reckoned and compared.

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

    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.

  2. Abordagem profunda e abordagem superficial à aprendizagem: diferentes perspectivas do rendimento escolar Deep and surface approach to learning: different perspectives about academic achievement

    Cristiano Mauro Assis Gomes

    2011-01-01

    Full Text Available O presente estudo investiga a relação entre a abordagem superficial e a abordagem profunda à aprendizagem na explicação do rendimento escolar. Algumas questões são delineadas buscando verificar o papel de cada uma das abordagens na proficiência escolar em séries distintas. Foram analisados dados de 684 estudantes da sexta série do ensino fundamental à terceira série do ensino médio de uma escola particular de Belo Horizonte, Minas Gerais. Foi delineado um modelo para comparação das séries escolares, através da modelagem por equação estrutural. O modelo desenhado apresentou bom grau de ajuste (c²=427,12; gl=182; CFI=0,95; RMSEA=0,04 para a amostra completa e para cada série escolar. Os resultados mostram que há uma participação distinta da abordagem superficial e da abordagem profunda no desempenho escolar nas diferentes séries. São discutidas implicações dos resultados para a teoria das abordagens.This study investigates the relationship between deep and surface approach to learning in explaining academic achievement. Some questions are outlined aiming to verify the role of each approach in student's proficiency in different grades. Data from 684 students from junior high school (6th year to high school (12th year of a private school in Belo Horizonte, Minas Gerais, were analyzed. A model was designed to compare the grades through structural equation modeling. The designed model showed a good fit (c² = 427.12; df = 182; CFI = .95, RMSEA = .04 for the full sample and for each grade. The results show that there is a distinct contribution of both approaches in academic achievement in the different grades. Further implications to the learning approach theory will be discussed.

  3. Surface Plasmon Wave Adapter Designed with Transformation Optics

    Zhang, Jingjing; Xiao, Sanshui; Wubs, Martijn;

    2011-01-01

    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....

  4. UOBPRM: A uniformly distributed obstacle-based PRM

    Yeh, Hsin-Yi

    2012-10-01

    This paper presents a new sampling method for motion planning that can generate configurations more uniformly distributed on C-obstacle surfaces than prior approaches. Here, roadmap nodes are generated from the intersections between C-obstacles and a set of uniformly distributed fixed-length segments in C-space. The results show that this new sampling method yields samples that are more uniformly distributed than previous obstacle-based methods such as OBPRM, Gaussian sampling, and Bridge test sampling. UOBPRM is shown to have nodes more uniformly distributed near C-obstacle surfaces and also requires the fewest nodes and edges to solve challenging motion planning problems with varying narrow passages. © 2012 IEEE.

  5. On topological spaces possessing uniformly distributed sequences

    Bogachev, V I

    2007-01-01

    Two classes of topological spaces are introduced on which every probability Radon measure possesses a uniformly distributed sequence or a uniformly tight uniformly distributed sequence. It is shown that these classes are stable under multiplication by completely regular Souslin spaces

  6. Uniform excitations in magnetic nanoparticles

    Mørup, Steen; Frandsen, Cathrine; Hansen, Mikkel Fougt

    2010-01-01

    We present a short review of the magnetic excitations in nanoparticles below the superparamagnetic blocking temperature. In this temperature regime, the magnetic dynamics in nanoparticles is dominated by uniform excitations, and this leads to a linear temperature dependence of the magnetization...... and the magnetic hyperfine field, in contrast to the Bloch T3/2 law in bulk materials. The temperature dependence of the average magnetization is conveniently studied by Mössbauer spectroscopy. The energy of the uniform excitations of magnetic nanoparticles can be studied by inelastic neutron scattering....

  7. Sublogarithmic uniform Boolean proof nets

    Aubert, Clément

    2012-01-01

    Using a proofs-as-programs correspondence, Terui was able to compare two models of parallel computation: Boolean circuits and proof nets for multiplicative linear logic. Mogbil et. al. gave a logspace translation allowing us to compare their computational power as uniform complexity classes. This paper presents a novel translation in AC0 and focuses on a simpler restricted notion of uniform Boolean proof nets. We can then encode constant-depth circuits and compare complexity classes below logspace, which were out of reach with the previous translations.

  8. Wave-current interaction, experiments with controlled uniform shear

    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.

  9. Mass-transport-controlled, large-area, uniform deposition of carbon nanofibers and their application in gas diffusion layers of fuel cells.

    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.

  10. Uniform approximation by (quantum) polynomials

    Drucker, A.; de Wolf, R.

    2011-01-01

    We show that quantum algorithms can be used to re-prove a classical theorem in approximation theory, Jackson's Theorem, which gives a nearly-optimal quantitative version of Weierstrass's Theorem on uniform approximation of continuous functions by polynomials. We provide two proofs, based respectivel

  11. Uniformer på arbejde

    Leilund, Helle

    Afhandlingen , Uniformer på arbejde - nutidige praksisser omkring ensartet arbejdstøj , har afsæt i det kulturhistoriske museums arbejde med ’ dragt ’ . På trods af at ensart et eller uniformt arbejdstøj er et velkendt dagligdags fænomen, som bruges af medarbejdere på mange nutidige arbejdspladser...

  12. Uniform Slavic Transliteration Alphabet (USTA).

    Dekleva, Borut

    The Uniform Slavic Transliteration Alphabet (USTA) was designed primarily with the following objectives: to aid librarians (catalogers and bibliographers), information scientists, transliterators, and editors of bibliographic works of the many Slavic tongues; and to serve as original research for the further development of a machine-readable…

  13. School Uniforms: Guidelines for Principals.

    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…

  14. Irradiation of poly(tetrafluoroethylene) surfaces by CF{sub 4} plasma to achieve robust superhydrophobic and enhanced oleophilic properties for biological applications

    Salapare, Hernando S., E-mail: hssalapare@up.edu.ph [Plasma Physics Laboratory, National Institute of Physics, College of Science, University of the Philippines Diliman, Quezon City 1101 (Philippines); eUP Office and UP Information Technology Development Center, University of the Philippines, Quezon City 1101 (Philippines); Suarez, Beverly Anne T. [Physics Department, De La Salle University, 2401 Taft Avenue, Manila (Philippines); Cosiñero, Hannah Shamina O.; Bacaoco, Miguel Y.; Ramos, Henry J. [Plasma Physics Laboratory, National Institute of Physics, College of Science, University of the Philippines Diliman, Quezon City 1101 (Philippines)

    2015-01-01

    Poly(tetrafluoroethylene) (PTFE) was irradiated by CF{sub 4} 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. - Highlights: • PTFE surfaces were treated with direct CF{sub 4} using the gas discharge ion source. • Stable superhydrophobic behavior with water contact angles as high as 156° was recorded. • Surface roughness increased as the surface exhibited enhanced hydrophobicity. • Carbon nanoparticles were observed on the superhydrophobic PTFE surface. • Enhanced oleophilic property was observed with change in the PDMS-oil contact angle from 33° to 10°.

  15. Irradiation of poly(tetrafluoroethylene) surfaces by CF4 plasma to achieve robust superhydrophobic and enhanced oleophilic properties for biological applications.

    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.

  16. Christiansen Revisited: Rethinking Quantification of Uniformity in Rainfall Simulator Studies

    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

  17. Uniformity Analysis for Index of Retail Price

    潘竞红; 曾庆洪; 刘梅英

    2002-01-01

    Using the Hodges-Ajne testing method, the uniformity of China retail price index was tested. The result, that population is submitting to uniform dist ribution, was obtained. The uniformity of CRPI indicates that the general price level is stable in the Ninth Five-Year Plan. Finally, the reasons causing the uniformity was analyzed.

  18. 46 CFR 310.11 - Cadet uniforms.

    2010-10-01

    ... 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 2010-10-01 2010-10-01 false Cadet uniforms. 310.11 Section 310.11 Shipping...

  19. Uniform-droplet spray forming

    Blue, C.A.; Sikka, V.K. [Oak Ridge National Lab., TN (United States); Chun, Jung-Hoon [Massachusetts Institute of Technology, Cambridge, MA (United States); Ando, T. [Tufts Univ., Medford, MA (United States)

    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.

  20. Note: 3D printed spheroid for uniform magnetic field generation

    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.

  1. Local self-uniformity in photonic networks

    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

  2. Image Correlation Microscopy for Uniform Illumination

    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

  3. Analytical Solution of Coupled Laminar Heat-Mass Transfer in a Tube with Uniform Heat Flux

    1992-01-01

    Analytical solution is obtained of coupled laminar heat-mass transfer in a tube with uniform heat flux.This corresponds to the case when a layer of sublimable material is coated on the inner surface of a tube with its outer surface heated by uniform heat flux and this coated material will sublime as gas flows throught the tube.

  4. Uniformity of accommodation across the visual field.

    Liu, Tao; Sreenivasan, Vidhyapriya; Thibos, Larry N

    2016-01-01

    We asked the question: Does accommodation change the eye's focusing power equally over the central visual field in emmetropic and myopic adult eyes? To answer this question we modified our laboratory scanning wavefront aberrometer to rapidly measure ocular refractive state over the central 30° diameter of visual field as a function of foveal accommodative demand. On average, ocular refractive state changed uniformly over the central visual field as the eye accommodated up to 6 D. Visual field maps of accommodative error (relative to a spherical target surface of constant vergence) reveal subtle patterns of deviation on the order of ± 0.5 D that are unique to the individual and relatively invariant to changes in accommodative state. Population mean maps for accommodative error are remarkably uniform across the central visual field, indicating the retina of the hypothetical "average eye" is conjugate to a sphere of constant target vergence for all states of accommodation, even though individual eyes might deviate from the mean due to random variations. No systematic difference between emmetropic and myopic eyes was evident. Since accuracy of accommodation across the central visual field is similar to that measured in the fovea, loss of image quality due to accommodative errors, which potentially drives myopia and may affect many aspects of visual function, will be similar across the central retina.

  5. Thomas Precession by Uniform Acceleration

    Pardy, Miroslav

    2015-01-01

    We determine the nonlinear transformations between coordinate systems which are mutually in a constant symmetrical accelerated motion. The maximal acceleration limit follows from the kinematical origin and it is an analogue of the maximal velocity in special relativity. We derive the dependence of mass, length, time, Doppler effect, Cherenkov effect and transition radiation angle on acceleration as an analogue phenomena in special theory of relativity. The last application of our method is the Thomas precession by uniform acceleration with the possible role in the modern physics and cosmology. The comparison of derived results with other relativistic methods is necessary.

  6. Non-uniform sediment incipient velocity

    Haitao XU; Jinyou LU; Xiaobin LIU

    2008-01-01

    Based on the mechanism of non-uniform sediment incipient motion,the dragging force and uplift force coefficient expressions are put forward for the non-uniform bed material exposure and close alignment state.The incipient veiocity formula of the non-uniform sediment is then established.It is shown that the formula structure is reasonable,and fine particles of the non-uniform sediment are more difficult to set into motion than the same sized uniform particles,whereas coarser particles are easier to set into motion than their uniform equivalents.The validity of the formula is verified by field and experiment data.

  7. Electromagnetic performance analysis of reflector antennas with non-uniform errors along radius

    Peiyuan Lian; Congsi Wang; Wei Wang; Binbin Xiang

    2016-01-01

    Based on the works of Greve and Rahmat-Sami , the electromagnetic (EM) performance of the reflector antenna with non-uniform surface errors along radius is further addressed. A mathematical model is developed to describe the weighting func-tion for the non-uniform surface errors along radius. Then, some discussions on the peak gain loss (PGL) and the first sidelobe level increase (SLLI) caused by the non-uniform surface errors are presented and several significant radiation characteristics of the reflector with non-uniform errors are pointed out. Last, based on the proposed model, the weighted root mean square (RMS) value of the surface errors is produced to evaluate the EM performance and several representative cases with different non-uniform errors are presented with good results. Results show that the weighted RMS value should be taken into account for a better quality evalu-ation of the reflector surface.

  8. Buffered Electropolishing – A New Way for Achieving Extremely Smooth Surface Finish on Nb SRF Cavities to be Used in Particle Accelerators

    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.

  9. Enhanced Biosensor Platforms for Detecting the Atherosclerotic Biomarker VCAM1 Based on Bioconjugation with Uniformly Oriented VCAM1-Targeting Nanobodies

    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

  10. Uniform generation of combinatorial structures

    Zito, M.; Pu, I.; Amos, M.; Gibbons, A. [Univ. of Warwick, Coventry (United Kingdom)

    1996-12-31

    We describe several RNC algorithms for generating graphs and subgraphs uniformly at random. For example, unlabelled undirected graphs are generated in O(log{sup 3} n lg lg n) time using O({epsilon}n{sup 1.5}/lg{sup 3} n lg lg n) processors if their number is n lg lg n known in advance and in O(lg n) time using O ({epsilon}n{sup 2}/lg n) processors otherwise. In both cases the error probability is the inverse of a polynomial in {epsilon}. Thus {epsilon} may be chosen to trade-off processors for error probability. Also, for an arbitrary graph, we describe RNC algorithms for the uniform generation of its subgraphs that are either non-simple paths or spanning trees. The work measure for the subgraph algorithms is essentially determined by the transitive closure bottleneck. As for sequential algorithms, the general notion of constructing generators from counters also applies to parallel algorithms although this approach is not employed by all the algorithms of this paper.

  11. Calculation of Uniform of Beam Scanning

    2011-01-01

    For the electron beam application, it is always scanned by a dipole magnet. The uniform of the scanning has great influence for some application, such as the irradiation of the thyristor. There are two methods for improving the scanning uniform:

  12. Design Techniques for Uniform-DFT, Linear Phase Filter Banks

    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.

  13. Attitudes of Parents about School Uniforms.

    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)

  14. Uniform magnetic excitations in nanoparticles

    Mørup, Steen; Hansen, Britt Rosendahl

    2005-01-01

    We have used a spin-wave model to calculate the temperature dependence of the (sublattice) magnetization of magnetic nanoparticles. The uniform precession mode, corresponding to a spin wave with wave vector q=0, is predominant in nanoparticles and gives rise to an approximately linear temperature...... dependence of the (sublattice) magnetization well below the superparamagnetic blocking temperature for both ferro-, ferri-, and antiferromagnetic particles. This is in accordance with the results of a classical model for collective magnetic excitations in nanoparticles. In nanoparticles of antiferromagnetic...... materials, quantum effects give rise to a small deviation from the linear temperature dependence of the (sublattice) magnetization at very low temperatures. The complex nature of the excited precession states of nanoparticles of antiferromagnetic materials, with deviations from antiparallel orientation...

  15. The assessment of the required groundwater quantity for the conservation of ecosystems and the achievement of a good ecological status of surface waters

    Mitja Janža

    2016-12-01

    Full Text Available Assessment of the available quantity of groundwater is of essential importance for its sustainable use. Modern approaches for estimation of groundwater availability take into account all potential impacts of abstractions, including impacts on groundwater dependent ecosystems and impacts on surface waters ecological status. Groundwater body is in good quantitative status if groundwater abstractions do not cause signifiant damages to groundwater dependent ecosystems and signifiant diminution in the ecological status of surface water bodies. The methodology presented in this paper was developed as an integral part of the assessment of the quantitative status of groundwater bodies in Slovenia and is tailored to the characteristics of the groundwater dependent ecosystems as well as hydrological and hydrogeological conditions in the Slovenian territory. Two different approaches were implemented; for forest habitats on alluvial aquifers, and habitats of amphibians and molluscs in karst areas. Estimates of the required quantity of groundwater for groundwater dependent ecosystems conservation were performed at the level of groundwater bodies and annual averages of temporal variables of the water balance, calculated with the regional water balance model GROWA-SI. In the areas of groundwater bodies with groundwater dependent ecosystems estimated quantity present 0.1 % - 12.4 % of the groundwater recharge. The estimated share of annual renewable quantity of groundwater to maintain the ecological status of surface waters for the entire territory of Slovenia is 23.2 %. The largest share, 30 % is in north-eastern Slovenia and the lowest in the north-west part of Slovenia with a 16.6 % average annual renewable quantity.

  16. Analysis of Basis Weight Uniformity of Microfiber Nonwovens and Its Impact on Permeability and Filtration Properties

    Amirnasr, Elham

    It is widely recognized that nonwoven basis weight non-uniformity affects various properties of nonwovens. However, few studies can be found in this topic. The development of uniformity definition and measurement methods and the study of their impact on various web properties such as filtration properties and air permeability would be beneficial both in industrial applications and in academia. They can be utilized as a quality control tool and would provide insights about nonwoven behaviors that cannot be solely explained by average values. Therefore, for quantifying nonwoven web basis weight uniformity we purse to develop an optical analytical tool. The quadrant method and clustering analysis was utilized in an image analysis scheme to help define "uniformity" and its spatial variation. Implementing the quadrant method in an image analysis system allows the establishment of a uniformity index that can be used to quantify the degree of uniformity. Clustering analysis has also been modified and verified using uniform and random simulated images with known parameters. Number of clusters and cluster properties such as cluster size, member and density was determined. We also utilized this new measurement method to evaluate uniformity of nonwovens produced with different processes and investigated impacts of uniformity on filtration and permeability. The results of quadrant method shows that uniformity index computed from quadrant method demonstrate a good range for non-uniformity of nonwoven webs. Clustering analysis is also been applied on reference nonwoven with known visual uniformity. From clustering analysis results, cluster size is promising to be used as uniformity parameter. It is been shown that non-uniform nonwovens has provide lager cluster size than uniform nonwovens. It was been tried to find a relationship between web properties and uniformity index (as a web characteristic). To achieve this, filtration properties, air permeability, solidity and

  17. Experimental Study on the Expansion Uniformity of Armature

    HE Yuan-hang; WU Bi; MA Yue-fen; ZHANG Qing-ming

    2009-01-01

    A measurement system has been developed based on high-precision printed probes in printed circuit board (PCB) and steep rising-time probe adapters,which can be applied to study the expansion uniformity of armature in a helical magnetic flux compression generator (HFCG).The influences of wall thickness and initiation position on the expansion uniformity of armature in HFCG were experimentally investigated.The results show that the armature with thinner wall thickness will easily rupture due to the high pressure of detonation products inside,the armature with larger wall thickness will easily crack due to the tensile stress on the outer surface of the wall,the influence of the end effect on the expansion uniformity can be ignored if the distance between the first group of probe and the initiation point is more than 3 times the armature diameter.

  18. Discovery of Uniformly Expanding Universe

    Cahill R. T.

    2012-01-01

    Full Text Available Saul Perlmutter and the Brian Schmidt – Adam Riess teams reported that their Friedmann-model GR-based analysis of their supernovae magnitude-redshift data re- vealed a new phenomenon of “dark energy” which, it is claimed, forms 73% of the energy / matter density of the present-epoch universe, and which is linked to the further claim of an accelerating expansion of the universe. In 2011 Perlmutter, Schmidt and Riess received the Nobel Prize in Physics “for the discovery of the accelerating ex- pansion of the Universe through observations of distant supernovae”. Here it is shown that (i a generic model-independent analysis of this data reveals a uniformly expanding universe, (ii their analysis actually used Newtonian gravity, and finally (iii the data, as well as the CMB fluctuation data, does not require “dark energy” nor “dark matter”, but instead reveals the phenomenon of a dynamical space, which is absent from the Friedmann model.

  19. Uniform guidelines improve client care.

    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.

  20. Uniform and Non-Uniform Optimum Scalar Quantizers Performances: A Comparative Study

    Fendy Santoso

    2008-05-01

    Full Text Available The aim of this research is to investigate source coding, the representation of information source output by finite R bits/symbol. The performance of optimum quantisers subject to an entropy constraint has been studied. The definitive work in this area is best summarised by Shannon’s source coding theorem, that is, a source with entropy H can be encoded with arbitrarily small error probability at any rate R (bits/source output as long as R>H. Conversely, If R the error probability will be driven away from zero, independent of the complexity of the encoder and the decoder employed. In this context, the main objective of engineers is however to design the optimum code. Unfortunately, the rate-distortion theorem does not provide the recipe for such a design. The theorem does, however, provide the theoretical limit so that we know how close we are to the optimum. The full understanding of the theorem also helps in setting the direction to achieve such an optimum. In this research, we have investigated the performances of two practical scalar quantisers, i.e., a Lloyd-Max quantiser and the uniformly defined one and also a well-known entropy coding scheme, i.e., Huffman coding against their theoretically attainable optimum performance due to Shannon’s limit R. It has been shown that our uniformly defined quantiser could demonstrate superior performance. The performance improvements, in fact, are more noticeable at higher bit rates.

  1. VARIABLE NON-UNIFORM QUANTIZED BELIEF PROPAGATION ALGORITHM FOR LDPC DECODING

    Liu Binbin; Bai Dong; Mei Shunliang

    2008-01-01

    Non-uniform quantization for messages in Low-Density Parity-Check (LDPC) decoding can reduce implementation complexity and mitigate performance loss. But the distribution of messages varies in the iterative decoding. This letter proposes a variable non-uniform quantized Belief Propaga- tion (BP) algorithm. The BP decoding is analyzed by density evolution with Gaussian approximation. Since the probability density of messages can be well approximated by Gaussian distribution, by the unbiased estimation of variance, the distribution of messages can be tracked during the iteration. Thus the non-uniform quantization scheme can be optimized to minimize the distortion. Simulation results show that the variable non-uniform quantization scheme can achieve better error rate performance and faster decoding convergence than the conventional non-uniform quantization and uniform quantization schemes.

  2. Alignment and Characterization of High Uniformity Imaging Spectrometers

    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.

  3. Gradient angle estimation by uniform directional simulation on a cone

    Ditlevsen, Ove Dalager

    1997-01-01

    A sample of uniformly distributed unit vectors on an n-dimensional spherical cone is generated. The distances to a given limit state surface in the directions of the unit vectors of the sample are calculated and each of these distances are projected on the cone axis. The theoretical distribution...... of these projections is derived assuming the limit-state surface to be a hyperplane. This distribution depends on the angle between the cone axis and the normal vector to the hyperplane. Assuming sufficient flatness of the actual limit-state surface within a neighbourhood of the cut point with the cone axis, the cone...

  4. The symbolism and myth surrounding nurses' uniform.

    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.

  5. School uniforms: tradition, benefit or predicament?

    Van Aardt, Annette Marie; Wilken, Ilani

    2012-01-01

    This article focuses on the controversies surrounding school uniforms. Roleplayers in this debate in South Africa are parents, learners and educators, and arguments centre on aspects such as identity, economy and the equalising effect of school uniforms, which are considered in the literature to be benefits. Opposing viewpoints highlight the fact that compulsory uniforms infringe on learners’ constitutional rights to self-expression. The aim of this research was to determine the perspectives ...

  6. On the Compactly Locally Uniformly Rotund Points of Orlicz Spaces

    Lili Chen; Yunan Cui

    2007-11-01

    In this paper, locally uniformly rotund points and compactly locally uniformly rotund points are introduced. Moreover, criteria for compactly locally uniformly rotund points in Orlicz spaces are given.

  7. Maximum Power Point tracking algorithm based on I-V characteristic of PV array under uniform and non-uniform conditions

    Kouchaki, Alireza; Iman-Eini, H.; Asaei, B.

    2012-01-01

    This paper presents a new algorithm based on characteristic equation of solar cells to determine the Maximum Power Point (MPP) of PV modules under partially shaded conditions (PSC). To achieve this goal, an analytic condition is introduced to determine uniform or non-uniform atmospheric condition...... to verify the accuracy and validity of the proposed method, different simulations are carried out in MATLAB-Simulink environment for various atmospheric conditions. © 2012 IEEE....

  8. Developing Work Uniforms for Women

    Bjerck, Mari

    2016-01-01

    This article is makes use of fieldwork to discuss and analyse a Norwegian product development project aimed at developing workwear for women in male dominated manual occupations. Making use of ethnographic methods and analysis can be valuable in showing how users’ experiences and practices can...... relations and achieving action-oriented results may be a challenge in innovation and development processes. This article explores such challenges in studying the use of clothes in specific work contexts, as well as capturing and mediating this experience with workwear in use....

  9. A Smart Cage With Uniform Wireless Power Distribution in 3D for Enabling Long-Term Experiments With Freely Moving Animals.

    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).

  10. Periodic envelopes of waves over non-uniform depth

    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.

  11. Uniform Deterministic Discrete Method for Three Dimensional Systems

    1997-01-01

    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 numercal accuracy.

  12. School Dress Codes and Uniform Policies.

    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…

  13. A Uniform Syntax and Discourse Structure

    Hardt, Daniel

    2013-01-01

    I present arguments in favor of the Uniformity Hypothesis: the hypothesis that discourse can extend syntax dependencies without conflicting with them. I consider arguments that Uniformity is violated in certain cases involving quotation, and I argue that the cases presented in the literature...

  14. On Uniform Convexity of Banach Spaces

    Qing Jin CHENG; Bo WANG; Cui Ling WANG

    2011-01-01

    This paper gives some relations and properties of several kinds of generalized convexity in Banach spaces. As a result, it proves that every kind of uniform convexity implies the Banach-Sakes property, and several notions of uniform convexity in literature are actually equivalent.

  15. Uniformly convex-transitive function spaces

    Rambla-Barreno, Fernando; Talponen, Jarno

    2009-01-01

    We introduce a property of Banach spaces called uniform convex-transitivity, which falls between almost transitivity and convex-transitivity. We will provide examples of uniformly convex-transitive spaces. This property behaves nicely in connection with some Banach-valued function spaces. As a consequence, we obtain new examples of convex-transitive Banach spaces.

  16. Student Dress Codes and Uniforms. Research Brief

    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…

  17. School Uniforms and Discourses on Childhood.

    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…

  18. School Uniform Policies: Students' Views of Effectiveness.

    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)

  19. A School Uniform Program That Works.

    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…

  20. Some results on uniform arithmetic circuit complexity

    Frandsen, Gudmund Skovbjerg; Valence, Mark; Barrington, David A. Mix

    1994-01-01

    We introduce a natural set of arithmetic expressions and define the complexity class AE to consist of all those arithmetic functions (over the fieldsF 2n) that are described by these expressions. We show that AE coincides with the class of functions that are computable with constant depth...... that if some such representation is X-uniform (where X is P or DLOGTIME), then the arithmetic complexity of a function (measured with X-uniform unbounded fan-in arithmetic circuits) is identical to the Boolean complexity of this function (measured with X-uniform threshold circuits). We show the existence...... and polynomial-size unbounded fan-in arithmetic circuits satisfying a natural uniformity constraint (DLOGTIME-uniformity). A 1-input and 1-output arithmetic function over the fieldsF2n may be identified with ann-input andn-output Boolean function when field elements are represented as bit strings. We prove...

  1. Testing for uniformity in multidimensional data.

    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.

  2. Capacitated Vehicle Routing with Non-Uniform Speeds

    Gortz, Inge Li; Nagarajan, Viswanath; Ravi, R

    2010-01-01

    The capacitated vehicle routing problem (CVRP) involves distributing (identical) items from a depot to a set of demand locations, using a single capacitated vehicle. We study a generalization of this problem to the setting of multiple vehicles having non-uniform speeds (that we call Heterogenous CVRP), and present a constant-factor approximation algorithm. The technical heart of our result lies in achieving a constant approximation to the following TSP variant (called Heterogenous TSP). Given a metric denoting distances between vertices, a depot r containing k vehicles with possibly different speeds, the goal is to find a tour for each vehicle (starting and ending at r), so that every vertex is covered in some tour and the maximum completion time is minimized. This problem is precisely Heterogenous CVRP when vehicles are uncapacitated. The presence of non-uniform speeds introduces difficulties for employing standard tour-splitting techniques. In order to get a better understanding of this technique in our con...

  3. Towards a Uniform Cooperative Platform: Cova Approach and Experience

    SHI MeiLin(史美林); JIANG JinLei(姜进磊)

    2003-01-01

    A cooperative platform called Cova is presented, which aims to uniformly model a wide range of cooperation scenarios and to reduce the groupware design and development work. To achieve these goals, Cova provides two facilities, namely a specification language for developers to describe various cooperation modes uniformly and a run-time system that provides some generalpurposed services guaranteeing the semantics specified. With these facilities, the developers can then concentrate on the application specific functions rather than the control mechanisms. Therefore, the development efficiency is promoted. This paper details the design and implementation issues of the platform including the model and the specification language, platform architecture,transaction management, service integration and so on. Application development with Cova platform is also covered.

  4. Clonal propagation of chemically uniform fennel plants through somatic embryoids.

    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.

  5. Chirped Pulse Microwave Spectroscopy in Pulsed Uniform Supersonic Flows

    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.

  6. Micro-cantilevers for non-destructive characterization of nanograss uniformity

    Petersen, Dirch Hjorth; Wang, Fei; Olesen, Mikkel Buster

    2011-01-01

    We demonstrate an application of three-way flexible micro four-point probes for indirect uniformity characterization of surface morphology. The mean sheet conductance of a quasi-planar 3D nanostructured surface is highly dependent on the surface morphology, and thus accurate sheet conductance mea...

  7. Keesler AFB, Mississippi. Revised Uniform Summary of Surface Weather Observations.

    1986-11-01

    WINODO PEED IN -NOTS DIRECTION 1 1-3 4-6 7-10 11-lb 17-21 22-27 28-33 34-40 41-47 48-55 6E 56 ICTAL MEAN IOEGREE5) I % WIND N _ _ _ _ I 5 7...47 48-55 GE 5b ICTAL MEAN IDEbREEST I x WINO N I 4.6 3.7 4.5 1.3 14.1 5.8 NNE I 3.0 3.5 3.1 .8 10.4 5.7 NE 1.9 3.4 1.8 7.2 5.1 ENE 2.2 2.2 1.0 5.3...DIRECTION I 1-3 4-6 7-10 11-16 17-21 22-27 28-33 34-40 41-47 48-55 GE 56 ICTAL MEAN (DFGREFS) & WIND

  8. Temperature Uniformity of Heated Mold Plate by Oscillating Heat Pipe

    Kamonpet Patrapon

    2015-01-01

    Full Text Available Uniformity of the temperature in the mold plate is of paramount important since it will affect the dimensional stability of the part produced. To provide uniform temperature to the metal plate, many factors need to be considered such as choice of heating technology, uniformity of a heat source, a type of control, etc. This paper aims to study the temperature uniformity of metal plate using closed-loop oscillating heat pipe (CLOHP as a heat transfer device. The metal plates which were P-20 with the size of 306 x 130 mm2 were used. Metal plate was gouged to a depth of 3 mm for installing the CLOHP. Distances from the heating device to the metal plate surface were 5 and 10 mm. The surface temperatures of the metal plate were controlled at 80, 90, 100, 110, 120, and 130°C. Sixteen pointa of temperature were recorded. The results were then compared to those using the heat source as the cartridge heater arranged in the similar way with the same heating capacity. Once the system entered the steady state, it was found that the temperature distribution of metal plate using the CLOHP has a deviation in the range of ± 1.00°C and ± 0.94°C at the CLOHP depth of 5 mm. and 10 mm., respectively. While those of using cartridge heater deviated in the range of ± 1.35°C and ± 1.16°C. Compare to the recommended value from the ASTM Standard that the mold surface temperature need to be in the range of ± 2.0°C, the CLOHP shows the very promising results.

  9. Whiteness formula in CIELAB uniform color space

    Guoxin He; Mingxun Zhou

    2007-01-01

    @@ Many attempts have been made to standardize the calculation of whiteness. Whiteness formulas currently in use satisfactorily characterize the appearance of commercial whiteness. However, they have poor correlations with the observers' evaluations, and are often unsuccessful in assessing tinted white samples.A whiteness formula in the CIELAB uniform color space is developed in this paper. Several whiteness formulas are analyzed and compared. The experimental results show that the whiteness formula in the CIELAB uniform color space agrees well with the visual ranking, and it is superior to the CIE whiteness formula and the others in visual correlativity, uniformity and applicability.

  10. Uniform supersaturated design and its construction

    方开泰; 葛根年; 刘民千

    2002-01-01

    Supersaturated designs are factorial designs in which the number of main effects is greater than the number of experimental runs. In this paper, a discrete discrepancy is proposed as a measure of uniformity for supersaturated designs, and a lower bound of this discrepancy is obtained asa benchmark of design uniformity. A construction method for uniform supersaturated designs via resolvable balanced incomplete block designs is also presented along with the investigation of properties of the resulting designs. The construction method shows a strong link between these two different kinds of designs.

  11. Uniform Facility Data Set US (UFDS-1997)

    U.S. Department of Health & Human Services — The Uniform Facility Data Set (UFDS), formerly the National Drug and Alcohol Treatment Unit Survey or NDATUS, was designed to measure the scope and use of drug abuse...

  12. 7 CFR 29.3563 - Uniformity.

    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 Facility Data Set US (UFDS-1998)

    U.S. Department of Health & Human Services — The Uniform Facility Data Set (UFDS) was designed to measure the scope and use of drug abuse treatment services in the United States. The survey collects information...

  14. Growing Uniform Graphene Disks and Films on Molten Glass for Heating Devices and Cell Culture.

    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.

  15. Regulation of the Deposition Morphology of Inkjet-Printed Crystalline Materials via Polydopamine Functional Coatings for Highly Uniform and Electrically Conductive Patterns.

    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

  16. Analytical examination of a spiral beam scanning method for uniform irradiation

    Fukuda, Mitsuhiro; Okumura, Susumu; Arakawa, Kazuo [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1997-03-01

    A new circular beam scanning method for uniform irradiation of high-energy, intense ion beams over a large area has been developed. A sweeping speed and a trajectory density in a radial direction are kept constant to obtain uniform fluence distribution. A radial position of a beam spot on a target and an angular frequency of the circular motion are expressed by an irrational function of time. The beam is swept continuously, and a beam trajectory becomes spiral. More than 90 % uniformity of the fluence distribution can been achieved over a large area. (author)

  17. Energy efficient LED layout optimization for near-uniform illumination

    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.

  18. Toward Uniformly Dispersed Battery Electrode Composite Materials: Characteristics and Performance.

    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.

  19. Leader as achiever.

    Dienemann, Jacqueline

    2002-01-01

    This article examines one outcome of leadership: productive achievement. Without achievement one is judged to not truly be a leader. Thus, the ideal leader must be a visionary, a critical thinker, an expert, a communicator, a mentor, and an achiever of organizational goals. This article explores the organizational context that supports achievement, measures of quality nursing care, fiscal accountability, leadership development, rewards and punishments, and the educational content and teaching strategies to prepare graduates to be achievers.

  20. Naturalness preserved enhancement algorithm for non-uniform illumination images.

    Wang, Shuhang; Zheng, Jin; Hu, Hai-Miao; Li, Bo

    2013-09-01

    Image enhancement plays an important role in image processing and analysis. Among various enhancement algorithms, Retinex-based algorithms can efficiently enhance details and have been widely adopted. Since Retinex-based algorithms regard illumination removal as a default preference and fail to limit the range of reflectance, the naturalness of non-uniform illumination images cannot be effectively preserved. However, naturalness is essential for image enhancement to achieve pleasing perceptual quality. In order to preserve naturalness while enhancing details, we propose an enhancement algorithm for non-uniform illumination images. In general, this paper makes the following three major contributions. First, a lightness-order-error measure is proposed to access naturalness preservation objectively. Second, a bright-pass filter is proposed to decompose an image into reflectance and illumination, which, respectively, determine the details and the naturalness of the image. Third, we propose a bi-log transformation, which is utilized to map the illumination to make a balance between details and naturalness. Experimental results demonstrate that the proposed algorithm can not only enhance the details but also preserve the naturalness for non-uniform illumination images.

  1. Achieving Control of Coating Process in your Foundry

    Di Muoio, G. L.; Tiedje, N. S.

    2015-01-01

    Achieving control of coating thickness in foundry moulds is needed in order to guarantee uniform properties of the mould but also to achieve control of drying time. Since drying time of water based coatings is heavily dependent on the amount of water present in the coating layer, a stable coating...

  2. Non-uniform sampled scalar diffraction calculation using non-uniform fast Fourier transform

    Shimobaba, Tomoyoshi; Oikawa, Minoru; Okada, Naohisa; Endo, Yutaka; Hirayama, Ryuji; Ito, Tomoyoshi

    2013-01-01

    Scalar diffraction calculations such as the angular spectrum method (ASM) and Fresnel diffraction, are widely used in the research fields of optics, X-rays, electron beams, and ultrasonics. It is possible to accelerate the calculation using fast Fourier transform (FFT); unfortunately, acceleration of the calculation of non-uniform sampled planes is limited due to the property of the FFT that imposes uniform sampling. In addition, it gives rise to wasteful sampling data if we calculate a plane having locally low and high spatial frequencies. In this paper, we developed non-uniform sampled ASM and Fresnel diffraction to improve the problem using the non-uniform FFT.

  3. A uniform parameterization of moment tensors

    Tape, C.; Tape, W.

    2015-12-01

    A moment tensor is a 3 x 3 symmetric matrix that expresses an earthquake source. We construct a parameterization of the five-dimensional space of all moment tensors of unit norm. The coordinates associated with the parameterization are closely related to moment tensor orientations and source types. The parameterization is uniform, in the sense that equal volumes in the coordinate domain of the parameterization correspond to equal volumes of moment tensors. Uniformly distributed points in the coordinate domain therefore give uniformly distributed moment tensors. A cartesian grid in the coordinate domain can be used to search efficiently over moment tensors. We find that uniformly distributed moment tensors have uniformly distributed orientations (eigenframes), but that their source types (eigenvalue triples) are distributed so as to favor double couples. An appropriate choice of a priori moment tensor probability is a prerequisite for parameter estimation. As a seemingly sensible choice, we consider the homogeneous probability, in which equal volumes of moment tensors are equally likely. We believe that it will lead to improved characterization of source processes.

  4. Nurses' uniform: an investigation of mobility.

    Stubbs, D A; Buckle, P W; Hudson, M P; Butler, P E; Rivers, P M

    1985-01-01

    An investigation of the mobility of nurses under three clothing conditions is reported. The need for such a study has arisen as a result of the concern over a possible mismatch between mobility and patient handling requirements. Thirty-seven nurses participated under two of the clothing conditions ('National' dress uniform, Trouser/tunic combination). In addition, ten of these nurses volunteered to provide control data by being measured in a leotard or a swimming costume. Eleven static and sixteen dynamic anthropometric measures were considered. Each nurse was asked to complete a short questionnaire, relating to her subjective attitudes to the uniform and to her own physical state at the time of measurement. Whilst both uniforms imposed restrictions on the shoulder girdle and trunk of up to 10%, the area of greatest concern was the mobility of the hip joint. Hip flexion was reduced by 26% in the dress uniform. The implications of these findings for patient handling procedures are discussed, as are those of the relationship between the environment and the material. Uniform and the nursing image is also considered.

  5. Uniform gold nanoarray formed by controlled IP6 micelles for chemical mapping

    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.

  6. The Complexity of Synthesizing Uniform Strategies

    Bastien Maubert

    2013-03-01

    Full Text Available We investigate uniformity properties of strategies. These properties involve sets of plays in order to express useful constraints on strategies that are not μ-calculus definable. Typically, we can state that a strategy is observation-based. We propose a formal language to specify uniformity properties, interpreted over two-player turn-based arenas equipped with a binary relation between plays. This way, we capture e.g. games with winning conditions expressible in epistemic temporal logic, whose underlying equivalence relation between plays reflects the observational capabilities of agents (for example, synchronous perfect recall. Our framework naturally generalizes many other situations from the literature. We establish that the problem of synthesizing strategies under uniformity constraints based on regular binary relations between plays is non-elementary complete.

  7. Functional uniform priors for nonlinear modeling.

    Bornkamp, Björn

    2012-09-01

    This article considers the topic of finding prior distributions when a major component of the statistical model depends on a nonlinear function. Using results on how to construct uniform distributions in general metric spaces, we propose a prior distribution that is uniform in the space of functional shapes of the underlying nonlinear function and then back-transform to obtain a prior distribution for the original model parameters. The primary application considered in this article is nonlinear regression, but the idea might be of interest beyond this case. For nonlinear regression the so constructed priors have the advantage that they are parametrization invariant and do not violate the likelihood principle, as opposed to uniform distributions on the parameters or the Jeffrey's prior, respectively. The utility of the proposed priors is demonstrated in the context of design and analysis of nonlinear regression modeling in clinical dose-finding trials, through a real data example and simulation.

  8. Uniform dimension results for Gaussian random fields

    WU DongSheng; XIAO YiMin

    2009-01-01

    Let X = {X(t), t ∈ RN} be a Gaussian random field with values in Rd defined by x(t) = (x1(t),…,xd(t)), At∈RN.(1)The properties of space and time anisotropy of X and their connections to uniform Hausdorff dimension results are discussed. It is shown that in general the uniform Hausdorff dimension result does not hold for the image sets of a space-anisotropic Gaussian random field X. When X is an (N, d)-Gaussian random field as in (1), where X1,..., Xd are independent copies of a real valued, centered Gaussian random field Xo which is anisotropic in the time variable. We establish uniform Hausdorff dimension results for the image sets of X. These results extend the corresponding results on one-dimensional Brownian motion, fractional Brownian motion and the Brownian sheet.

  9. Uniform dimension results for Gaussian random fields

    2009-01-01

    Let X = {X(t),t ∈ RN} be a Gaussian random field with values in Rd defined by X(t) =(X1(t),...,Xd(t)), t ∈ RN.(1) The properties of space and time anisotropy of X and their connections to uniform Hausdorff dimension results are discussed.It is shown that in general the uniform Hausdorff dimension result does not hold for the image sets of a space-anisotropic Gaussian random field X.When X is an(N,d)-Gaussian random field as in(1),where X1,...,Xd are independent copies of a real valued,centered Gaussian random field X0 which is anisotropic in the time variable.We establish uniform Hausdorff dimension results for the image sets of X.These results extend the corresponding results on one-dimensional Brownian motion,fractional Brownian motion and the Brownian sheet.

  10. Elastic stability of non-uniform columns

    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.

  11. Electromechanical characterization of non-uniform charged ionic polymer-metal composites (IPMC) devices

    Lopes, B; Branco, P J C [Institute Superior Tecnico, DEEC - Energia, Lisboa 1096-001 (Portugal)], E-mail: pbranco@ist.utl.pt

    2008-08-15

    Research on electromechanical characterization of non-uniformly charged IPMCs is quasi-absent. This has limited their use to only those devices where the IPMC is completely covered with electrode surfaces (uniformly charged). In this paper, we develop a theoretical study for electromechanical characterization of non-uniformly charged IPMCs. A continuum model taking into account the gravitational forces, important for large IPMCs, is presented. Based on this approach, FEM analysis of IPMC devices using Comsol Multiphysics is introduced in a very simple way. Three devices have been studied, comparing the analytical model results with those ones obtained from a FEM analysis.

  12. Using chitosan as a thickener for electrospinning dilute PVA solutions to improve fibre uniformity

    Lin, Tong; Fang, Jian; Wang, Hongxia; Cheng, Tong; Wang, Xungai

    2006-08-01

    Chitosan was added to PVA aqueous solutions as a thickener to improve the electrospinning process. The presence of a small amount of chitosan considerably improved the uniformity of as-spun nanofibres. This improvement is attributed to its significant effect on the solution viscosity and conductivity, with only a slight impact on the surface tension. The concentration of the PVA required to produce bead-free and uniform nanofibres was reduced with the increase in chitosan concentration. The chitosan thickener suppressed the jet break-up and facilitated the jet stretching so that fine and uniform fibres could be electrospun even from a dilute PVA solution.

  13. Using chitosan as a thickener for electrospinning dilute PVA solutions to improve fibre uniformity

    Lin Tong; Fang Jian; Wang Hongxia; Cheng Tong; Wang Xungai [Centre for Material and Fibre Innovation, Faculty of Science and Technology, Deakin University, Geelong, VIC 3217 (Australia)

    2006-08-14

    Chitosan was added to PVA aqueous solutions as a thickener to improve the electrospinning process. The presence of a small amount of chitosan considerably improved the uniformity of as-spun nanofibres. This improvement is attributed to its significant effect on the solution viscosity and conductivity, with only a slight impact on the surface tension. The concentration of the PVA required to produce bead-free and uniform nanofibres was reduced with the increase in chitosan concentration. The chitosan thickener suppressed the jet break-up and facilitated the jet stretching so that fine and uniform fibres could be electrospun even from a dilute PVA solution.

  14. Non-uniform impact excitation of a cylindrical bar

    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.

  15. Uniform wire segmentation algorithm of distributed interconnects

    Yin Guoli; Lin Zhenghui

    2007-01-01

    A uniform wire segmentation algorithm for performance optimization of distributed RLC interconnects was proposed in this paper. The optimal wire length for identical segments and buffer size for buffer insertion are obtained through computation and derivation, based on a 2-pole approximation model of distributed RLC interconnect. For typical inductance value and long wires under 180nm technology, experiments show that the uniform wire segmentation technique proposed in the paper can reduce delay by about 27% ~ 56% , while requires 34%~69% less total buffer usage and thus 29% to 58% less power consumption. It is suitable for long RLC interconnect performance optimization.

  16. On Uniform Motion of a Periodic System of Absolutely Rigid Stamps, in the Hollow Cylinder

    Amirjanyan H. A.

    2011-03-01

    Full Text Available Axissymetric stress state of the infinite hollow cylinder when on the inner surface of the cylinder acts a periodic system of uniformly moving circular stamps and the outer surface is free of loads or rigidly clamped is considered The behavior of the contact stresses, acting under the stamp, in dependence on the physical and geometrical parameters of the cylinder is studied.

  17. Reductively Responsive Hydrogel Nanoparticles with Uniform Size, Shape, and Tunable Composition for Systemic siRNA Delivery in Vivo.

    Ma, Da; Tian, Shaomin; Baryza, Jeremy; Luft, J Christopher; DeSimone, Joseph M

    2015-10-01

    To achieve the great potential of siRNA based gene therapy, safe and efficient systemic delivery in vivo is essential. Here we report reductively responsive hydrogel nanoparticles with highly uniform size and shape for systemic siRNA delivery in vivo. "Blank" hydrogel nanoparticles with high aspect ratio were prepared using continuous particle fabrication based on PRINT (particle replication in nonwetting templates). Subsequently, siRNA was conjugated to "blank" nanoparticles via a disulfide linker with a high loading ratio of up to 18 wt %, followed by surface modification to enhance transfection. This fabrication process could be easily scaled up to prepare large quantity of hydrogel nanoparticles. By controlling hydrogel composition, surface modification, and siRNA loading ratio, siRNA conjugated nanoparticles were highly tunable to achieve high transfection efficiency in vitro. FVII-siRNA conjugated nanoparticles were further stabilized with surface coating for in vivo siRNA delivery to liver hepatocytes, and successful gene silencing was demonstrated at both mRNA and protein levels.

  18. Differences between laminar convections through parallel plain planes with uniform wall temperature and heat flux in terms of process parameter

    2010-01-01

    Using the process parameter description,we analyzed the difference between the characteristics of laminar convections through parallel plain planes with uniform temperature and heat flux.The results show the following.(1)On the wall surface of the developing region,under uniform heat flux boundary condition,the heat flux normal to the wall surface is transported through a convection process although the velocity is zero;the velocity gradient contributes to this transport,but under uniform temperature boundary condition,the heat flux normal to the wall surface is transported through a difussion process.(2)Inside the flow of the developing region,whether under uniform temperature or heat flux boundary condition,the heat flux along the main flow direction and the heat flux normal to the wall surface are transported through a convection process,and the contributions of velocity and velocity gradient are dependent on the thermal boundary condition.(3)On the wall surface of the fully developed region,under uniform heat flux boundary condition,the heat flux normal to the wall surface is transported through a convection process;the velocity gradient contributes to this transport,but under uniform temperature boundary condition,the heat flux normal to the wall surface is transported through a diffusion process.(4)Inside the flow of the fully developed region,under uniform temperature boundary condition,the heat flux along the main flow direction and the heat flux normal to the wall surface are transported through a convection process,and the velocity and velocity gradient contribute to these transports;under uniform heat flux boundary condition,the heat flux along the main flow direction and the heat flux normal to the wall surface are transported through a convection process.Furthermore,the transport of the heat flux along the main flow direction is a no-net convection process;the velocity gradient contributes to the transport of the heat flux only in the normal direction

  19. Uniform design of experiments with mixtures

    王元; 方开泰

    1996-01-01

    Consider a design of experiments with mixtures:0≤aiuniform distribution in number theory.

  20. Uniform color spaces and natural image statistics.

    McDermott, Kyle C; Webster, Michael A

    2012-02-01

    Many aspects of visual coding have been successfully predicted by starting from the statistics of natural scenes and then asking how the stimulus could be efficiently represented. We started from the representation of color characterized by uniform color spaces, and then asked what type of color environment they implied. These spaces are designed to represent equal perceptual differences in color discrimination or appearance by equal distances in the space. The relative sensitivity to different axes within the space might therefore reflect the gamut of colors in natural scenes. To examine this, we projected perceptually uniform distributions within the Munsell, CIE L(*)u(*)v(*) or CIE L(*)a(*)b(*) spaces into cone-opponent space. All were elongated along a bluish-yellowish axis reflecting covarying signals along the L-M and S-(L+M) cardinal axes, a pattern typical (though not identical) to many natural environments. In turn, color distributions from environments were more uniform when projected into the CIE L(*)a(*)b(*) perceptual space than when represented in a normalized cone-opponent space. These analyses suggest the bluish-yellowish bias in environmental colors might be an important factor shaping chromatic sensitivity, and also suggest that perceptually uniform color metrics could be derived from natural scene statistics and potentially tailored to specific environments.

  1. On Uniform Weak König's Lemma

    Kohlenbach, Ulrich

    2002-01-01

    is of interest in the context of explicit mathematics as developed by S. Feferman. The elimination process in Kohlenbach [10] actually can be used to eliminate even this uniform weak Konig's lemma provided that PRA only has a quantifier-free rule of extensionality QF-ER instead of the full axioms (E...

  2. Downsampling Non-Uniformly Sampled Data

    Fredrik Gustafsson

    2007-10-01

    Full Text Available Decimating a uniformly sampled signal a factor D involves low-pass antialias filtering with normalized cutoff frequency 1/D followed by picking out every Dth sample. Alternatively, decimation can be done in the frequency domain using the fast Fourier transform (FFT algorithm, after zero-padding the signal and truncating the FFT. We outline three approaches to decimate non-uniformly sampled signals, which are all based on interpolation. The interpolation is done in different domains, and the inter-sample behavior does not need to be known. The first one interpolates the signal to a uniformly sampling, after which standard decimation can be applied. The second one interpolates a continuous-time convolution integral, that implements the antialias filter, after which every Dth sample can be picked out. The third frequency domain approach computes an approximate Fourier transform, after which truncation and IFFT give the desired result. Simulations indicate that the second approach is particularly useful. A thorough analysis is therefore performed for this case, using the assumption that the non-uniformly distributed sampling instants are generated by a stochastic process.

  3. Uniforms: Are They a Good Fit?

    Boutelle, Marsha

    2008-01-01

    In an era where some parents seem unwilling or unable to draw the "clothes" line with their children, where pop culture influences kids' clothing choices as never before, and school safety--including gang violence--is at the top of everyone's minds, school uniforms and dress codes can play a significant role. What that role should be, however, is…

  4. MODERATOR ELEMENTS FOR UNIFORM POWER NUCLEAR REACTOR

    Balent, R.

    1963-03-12

    This patent describes a method of obtaining a flatter flux and more uniform power generation across the core of a nuclear reactor. The method comprises using moderator elements having differing moderating strength. The elements have an increasing amount of the better moderating material as a function of radial and/or axial distance from the reactor core center. (AEC)

  5. Uniformly convex and strictly convex Orlicz spaces

    Masta, Al Azhary

    2016-02-01

    In this paper we define the new norm of Orlicz spaces on ℝn through a multiplication operator on an old Orlicz spaces. We obtain some necessary and sufficient conditions that the new norm to be a uniformly convex and strictly convex spaces.

  6. On fixed points and uniformly convex spaces

    Gelander, Tsachik

    2008-01-01

    The purpose of this note is to present two elementary, but useful, facts concerning actions on uniformly convex spaces. We demonstrate how each of them can be used in an alternative proof of the triviality of the first $L_p$-cohomology of higher rank simple Lie groups, proved in [BFGM].

  7. Magnetostatics of the uniformly polarized torus

    Beleggia, Marco; De Graef, Marc; Millev, Yonko

    2009-01-01

    We provide an exhaustive description of the magnetostatics of the uniformly polarized torus and its derivative self-intersecting (spindle) shapes. In the process, two complementary approaches have been implemented, position-space analysis of the Laplace equation with inhomogeneous boundary...

  8. Towards a uniform analysis of 'any'

    van Rooij, R.

    2008-01-01

    In this paper, Universal any and Negative Polarity Item any are uniformly analyzed as ‘counterfactual’ donkey sentences (in disguise). Their difference in meaning is reduced here to the distinction between strong and weak readings of donkey sentences. It is shown that this explains the universal and

  9. UMAPRM: Uniformly sampling the medial axis

    Yeh, Hsin-Yi Cindy

    2014-05-01

    © 2014 IEEE. Maintaining clearance, or distance from obstacles, is a vital component of successful motion planning algorithms. Maintaining high clearance often creates safer paths for robots. Contemporary sampling-based planning algorithms That utilize The medial axis, or The set of all points equidistant To Two or more obstacles, produce higher clearance paths. However, They are biased heavily Toward certain portions of The medial axis, sometimes ignoring parts critical To planning, e.g., specific Types of narrow passages. We introduce Uniform Medial Axis Probabilistic RoadMap (UMAPRM), a novel planning variant That generates samples uniformly on The medial axis of The free portion of Cspace. We Theoretically analyze The distribution generated by UMAPRM and show its uniformity. Our results show That UMAPRM\\'s distribution of samples along The medial axis is not only uniform but also preferable To other medial axis samplers in certain planning problems. We demonstrate That UMAPRM has negligible computational overhead over other sampling Techniques and can solve problems The others could not, e.g., a bug Trap. Finally, we demonstrate UMAPRM successfully generates higher clearance paths in The examples.

  10. School Uniforms in Urban Public High Schools

    Draa, Virginia Ann Bendel

    2005-01-01

    The purpose of this study was to determine whether or not the implementation of a mandatory uniform policy in urban public high schools improved school performance measures at the building level for rates of attendance, graduation, academic proficiency, and student conduct as measured by rates of suspensions and expulsions. Sixty-four secondary…

  11. School Uniform Revisited: Procedure, Pressure and Equality

    Carney, Damian; Sinclair, Adele

    2006-01-01

    The House of Lords' decision in "R. (on the application of Begum) v. The Headteacher and Governors of Denbigh High School" considered whether a particular school uniform policy infringed a student's right to manifest her religion under Article 9. This paper analyses the content of this decision, and explores how schools should approach…

  12. Mandatory School Uniforms and Freedom of Expression

    Vopat, Mark C.

    2010-01-01

    On 10 December 2007 the Akron City School Board--following the precedent set by many school systems across the United States and the world--instituted a policy of mandatory school uniforms for all students in grades K-8. The measure was met with mixed reviews. While many parents supported the measure, a small group of parents from a selective,…

  13. Uniforms: Are They a Good Fit?

    Boutelle, Marsha

    2008-01-01

    In an era where some parents seem unwilling or unable to draw the "clothes" line with their children, where pop culture influences kids' clothing choices as never before, and school safety--including gang violence--is at the top of everyone's minds, school uniforms and dress codes can play a significant role. What that role should be,…

  14. Antagonistic growth regulation by Dpp and Fat drives uniform cell proliferation.

    Schwank, Gerald; Tauriello, Gerardo; Yagi, Ryohei; Kranz, Elizabeth; Koumoutsakos, Petros; Basler, Konrad

    2011-01-18

    We use the Dpp morphogen gradient in the Drosophila wing disc as a model to address the fundamental question of how a gradient of a growth factor can produce uniform growth. We first show that proper expression and subcellular localization of components in the Fat tumor-suppressor pathway, which have been argued to depend on Dpp activity differences, are not reliant on the Dpp gradient. We next analyzed cell proliferation in discs with uniformly high Dpp or uniformly low Fat signaling activity and found that these pathways regulate growth in a complementary manner. While the Dpp mediator Brinker inhibits growth in the primordium primarily in the lateral regions, Fat represses growth mostly in the medial region. Together, our results indicate that the activities of both signaling pathways are regulated in a parallel rather than sequential manner and that uniform proliferation is achieved by their complementary action on growth.

  15. Growth and structural characterization of pyramidal site-controlled quantum dots with high uniformity and spectral purity

    Dimastrodonato, Valeria; Young, Robert J; Pelucchi, Emanuele

    2010-01-01

    This work presents some fundamental features of pyramidal site-controlled InGaAs Quantum Dots (QDs) grown by MetalOrganic Vapour Phase Epitaxy on patterned GaAs (111)B substrate. The dots self-form inside pyramidal recesses patterned on the wafer via pre-growth processing. The major advantage of this growth technique is the control it provides over the dot nucleation posi-tion and the dimensions of the confined structures onto the sub-strate. The fundamental steps of substrate patterning and the QD forma-tion mechanism are described together with a discussion of the structural particulars. The post-growth processes, including sur-face etching and substrate removal, which are required to facili-tate optical characterization, are discussed. With this approach extremely high uniformity and record spectral purity are both achieved.

  16. Scraped surface heat exchangers.

    Rao, Chetan S; Hartel, Richard W

    2006-01-01

    Scraped surface heat exchangers (SSHEs) are commonly used in the food, chemical, and pharmaceutical industries for heat transfer, crystallization, and other continuous processes. They are ideally suited for products that are viscous, sticky, that contain particulate matter, or that need some degree of crystallization. Since these characteristics describe a vast majority of processed foods, SSHEs are especially suited for pumpable food products. During operation, the product is brought in contact with a heat transfer surface that is rapidly and continuously scraped, thereby exposing the surface to the passage of untreated product. In addition to maintaining high and uniform heat exchange, the scraper blades also provide simultaneous mixing and agitation. Heat exchange for sticky and viscous foods such as heavy salad dressings, margarine, chocolate, peanut butter, fondant, ice cream, and shortenings is possible only by using SSHEs. High heat transfer coefficients are achieved because the boundary layer is continuously replaced by fresh material. Moreover, the product is in contact with the heating surface for only a few seconds and high temperature gradients can be used without the danger of causing undesirable reactions. SSHEs are versatile in the use of heat transfer medium and the various unit operations that can be carried out simultaneously. This article critically reviews the current understanding of the operations and applications of SSHEs.

  17. Longitudinal oscillations in a non-uniform spatially dispersive plasma

    Calogeracos, Alex, E-mail: a.calogeracos@yahoo.co.uk

    2015-03-15

    Longitudinal oscillations of the electron fluid in the hydrodynamic model of a metal are examined with pressure effects taken into account. It is well-known that this entails spatial dispersion. The equilibrium electron number density is taken to be non-uniform and a non-self-adjoint fourth order differential equation obeyed by the electric potential is derived. A velocity potential necessary for the description of sound waves is introduced in the standard fashion and the generalized version of Bloch orthogonality appropriate to a non-uniform background is deduced. We observe a duality between electric and velocity potentials in the sense that the respective differential operators are adjoint to each other. The spectrum is calculated in the special case of an exponential profile for the equilibrium electron number density. The surface plasmons are connected with the analytic properties of the scattering amplitude in the complex plane. The phase shift at threshold is expressed in terms of the number of surface plasmon modes via an expression reminiscent of Levinson’s statement in quantum mechanics.

  18. Molecular Dynamics Simulations of Janus Particle Dynamics in Uniform Flow

    Archereau, Aurelien Y M; Willmott, Geoff R

    2016-01-01

    We use molecular dynamics simulations to study the dynamics of Janus particles, micro- or nanoparticles which are not spherically symmetric, in the uniform flow of a simple liquid. In particular we consider spheres with an asymmetry in the solid-liquid interaction over their surfaces and calculate the forces and torques experienced by the particles as a function of their orientation with respect to the flow. We also examine particles that are deformed slightly from a spherical shape. We compare the simulation results to the predictions of a previously introduced theoretical approach, which computes the forces and torques on particles with variable slip lengths or aspherical deformations that are much smaller than the particle radius. We find that there is good agreement between the forces and torques computed from our simulations and the theoretical predictions, when the slip condition is applied to the first layer of liquid molecules adjacent to the surface.

  19. A curvature filter and PDE based non-uniformity correction algorithm

    Cheng, Kuanhong; Zhou, Huixin; Qin, Hanlin; Zhao, Dong; Qian, Kun; Rong, Shenghui; Yin, Shimin

    2016-10-01

    In this paper, a curvature filter and PDE based non-uniformity correction algorithm is proposed, the key point of this algorithm is the way to estimate FPN. We use anisotropic diffusion to smooth noise and Gaussian curvature filter to extract the details of original image. Then combine these two parts together by guided image filter and subtract the result from original image to get the crude approximation of FPN. After that, a Temporal Low Pass Filter (TLPF) is utilized to filter out random noise and get the accurate FPN. Finally, subtract the FPN from original image to achieve non-uniformity correction. The performance of this algorithm is tested with two infrared image sequences, and the experimental results show that the proposed method achieves a better non-uniformity correction performance.

  20. Uniform stable-isotope labeling in mammalian cells: formulation of a cost-effective culture medium

    Egorova-Zachernyuk, T.A.; Bosman, G.J.C.G.M.; Grip, W.J. de

    2011-01-01

    Uniform stable-isotope labeling of mammalian cells is achieved via a novel formulation of a serum-free cell culture medium that is based on stable-isotope-labeled autolysates and lipid extracts of various microbiological origin. Yeast autolysates allow complete replacement of individual amino acids

  1. 'No delays achiever'.

    2007-05-01

    The latest version of the NHS Institute for Innovation and Improvement's 'no delays achiever', a web based tool created to help NHS organisations achieve the 18-week target for GP referrals to first treatment, is available at www.nodelaysachiever.nhs.uk.

  2. Laser Non-Uniform Heating of Moving Thin Wires Below the Biot Number Criterion of Uniform Temperature

    Wickramasooriya, Thiwanka; Vaidyanathan, Raj; Kar, Aravinda

    2016-06-01

    An analytic solution is obtained for three-dimensional quasi-steady state temperature distribution during laser heating of moving thin wires. The wire moves at a constant speed through a vacuum chamber, which is back-filled with an inert gas such as argon, and a laser beam of rectangular cross-section is incident on the wire. The ambient gas provides a convection heat transfer mechanism, which yields a Biot number, Bi, for the heating process to determine whether the temperature distribution would be uniform or nonuniform in the cross-section of the wire. Generally, the criterion of Bi less than 0.1 is applied to assume spatially uniform temperature distribution in a solid. The temperature distribution is determined for different Bi numbers and the variation of the temperature in the azimuthal direction is analyzed. The method of solution involves the Fourier transform in the azimuthal direction and the Hankel transform in the radial direction for a three-dimensional quasi-steady state heat conduction equation containing an advection term that accounts for the motion of the wire. The thermal and optical properties of the material is assumed to be constant in the temperature range of this study. The heat loss due to radiation heat transfer between the wire surface and the surrounding environment is neglected due to the small laser-heated surface area. Using this model, the temperature profile is studied for different process parameters such as the incident laser power, laser beam profile, Biot number, and wire speed.

  3. Uniform Algebras Over Complete Valued Fields

    Mason, Jonathan W

    2012-01-01

    UNIFORM algebras have been extensively investigated because of their importance in the theory of uniform approximation and as examples of complex Banach algebras. An interesting question is whether analogous algebras exist when a complete valued field other than the complex numbers is used as the underlying field of the algebra. In the Archimedean setting, this generalisation is given by the theory of real function algebras introduced by S. H. Kulkarni and B. V. Limaye in the 1980s. This thesis establishes a broader theory accommodating any complete valued field as the underlying field by involving Galois automorphisms and using non-Archimedean analysis. The approach taken keeps close to the original definitions from the Archimedean setting. Basic function algebras are defined and generalise real function algebras to all complete valued fields. Several examples are provided. Each basic function algebra is shown to have a lattice of basic extensions related to the field structure. In the non-Archimedean settin...

  4. Non-uniform tube representation of proteins

    Hansen, Mikael Sonne

    might not correctly capture volume exclusion - of crucial importance when trying to understand a proteins $3$d-structure. We propose a new reduced model treating the protein as a non-uniform tube with a radius reflecting the positions of atoms. The tube representation is well suited considering X......Treating the full protein structure is often neither computationally nor physically possible. Instead one is forced to consider various reduced models capturing the properties of interest. Previous work have used tubular neighborhoods of the C-alpha backbone. However, assigning a unique radius......-ray crystallographic resolution ~ 3Å while a varying radius accounts for the different sizes of side chains. Such a non-uniform tube better capture the protein geometry and has numerous applications in structural/computational biology from the classification of protein structures to sequence-structure prediction....

  5. Non-Uniform Tube Representation of Proteins

    Hansen, Mikael Sonne

    might not correctly capture volume exclusion - of crucial importance when trying to understand a protein's 3d-structure. We propose a new reduced model treating the protein as a non-uniform tube with a radius reflecting the positions of atoms. The tube representation is well suited considering X......Treating the full protein structure is often neither computationally nor physically possible. Instead one is forced to consider various reduced models capturing the properties of interest. Previous work have used tubular neighborhoods of the C-alpha backbone. However, assigning a unique radius......-ray crystallographic resolution ~ 3Å while a varying radius accounts for the different sizes of side chains. Such a non-uniform tube better captures the protein geometry and has numerous applications in structural/computational biology from the classification of protein structures to sequence-structure prediction....

  6. Student academic achievement in college chemistry

    Tabibzadeh, Kiana S.

    General Chemistry is required for variety of baccalaureate degrees, including all medical related fields, engineering, and science majors. Depending on the institution, the prerequisite requirement for college level General Chemistry varies. The success rate for this course is low. The purpose of this study is to examine the factors influencing student academic achievement and retention in General Chemistry at the college level. In this study student achievement is defined by those students who earned grades of "C" or better. The dissertation contains in-depth studies on influence of Intermediate Algebra as a prerequisite compared to Fundamental Chemistry for student academic achievement and student retention in college General Chemistry. In addition the study examined the extent and manner in which student self-efficacy influences student academic achievement in college level General Chemistry. The sample for this part of the study is 144 students enrolled in first semester college level General Chemistry. Student surveys determined student self-efficacy level. The statistical analyses of study demonstrated that Fundamental Chemistry is a better prerequisite for student academic achievement and student retention. The study also found that student self-efficacy has no influence on student academic achievement. The significance of this study will be to provide data for the purpose of establishing a uniform and most suitable prerequisite for college level General Chemistry. Finally the variables identified to influence student academic achievement and enhance student retention will support educators' mission to maximize the students' ability to complete their educational goal at institutions of higher education.

  7. Physical optics in a uniform gravitational field

    Hacyan, Shahen

    2012-01-01

    The motion of a (quasi-)plane wave in a uniform gravitational field is studied. It is shown that the energy of an elliptically polarized wave does not propagate along a geodesic, but in a direction that is rotated with respect to the gravitational force. The similarity with the walk-off effect in anisotropic crystals or the optical Magnus effect in inhomogeneous media is pointed out.

  8. Dynamic Uniform Scaling for Multiobjective Genetic Algorithms

    Pedersen, Gerulf; Goldberg, David E.

    2004-01-01

    Before Multiobjective Evolutionary Algorithms (MOEAs) can be used as a widespread tool for solving arbitrary real world problems there are some salient issues which require further investigation. One of these issues is how a uniform distribution of solutions along the Pareto non-dominated front can......, the issue of obtaining a diverse set of solutions for badly scaled objective functions will be investigated and proposed solutions will be implemented using the NSGA-II algorithm....

  9. Dynamic Uniform Scaling for Multiobjective Genetic Algorithms

    Pedersen, Gerulf; Goldberg, D.E.

    2004-01-01

    Before Multiobjective Evolutionary Algorithms (MOEAs) can be used as a widespread tool for solving arbitrary real world problems there are some salient issues which require further investigation. One of these issues is how a uniform distribution of solutions along the Pareto non-dominated front c......, the issue of obtaining a diverse set of solutions for badly scaled objective functions will be investigated and proposed solutions will be implemented using the NSGA-II algorithm....

  10. Beam uniformity of flat top lasers

    Chang, Chao; Cramer, Larry; Danielson, Don; Norby, James

    2015-03-01

    Many beams that output from standard commercial lasers are multi-mode, with each mode having a different shape and width. They show an overall non-homogeneous energy distribution across the spot size. There may be satellite structures, halos and other deviations from beam uniformity. However, many scientific, industrial and medical applications require flat top spatial energy distribution, high uniformity in the plateau region, and complete absence of hot spots. Reliable standard methods for the evaluation of beam quality are of great importance. Standard methods are required for correct characterization of the laser for its intended application and for tight quality control in laser manufacturing. The International Organization for Standardization (ISO) has published standard procedures and definitions for this purpose. These procedures have not been widely adopted by commercial laser manufacturers. This is due to the fact that they are unreliable because an unrepresentative single-pixel value can seriously distort the result. We hereby propose a metric of beam uniformity, a way of beam profile visualization, procedures to automatically detect hot spots and beam structures, and application examples in our high energy laser production.

  11. The non-uniformity of fossil preservation.

    Holland, Steven M

    2016-07-19

    The fossil record provides the primary source of data for calibrating the origin of clades. Although minimum ages of clades are given by the oldest preserved fossil, these underestimate the true age, which must be bracketed by probabilistic methods based on multiple fossil occurrences. Although most of these methods assume uniform preservation rates, this assumption is unsupported over geological timescales. On geologically long timescales (more than 10 Myr), the origin and cessation of sedimentary basins, and long-term variations in tectonic subsidence, eustatic sea level and sedimentation rate control the availability of depositional facies that preserve the environments in which species lived. The loss of doomed sediments, those with a low probability of preservation, imparts a secular trend to fossil preservation. As a result, the fossil record is spatially and temporally non-uniform. Models of fossil preservation should reflect this non-uniformity by using empirical estimates of fossil preservation that are spatially and temporally partitioned, or by using indirect proxies of fossil preservation. Geologically, realistic models of preservation will provide substantially more reliable estimates of the origination of clades.This article is part of the themed issue 'Dating species divergences using rocks and clocks'.

  12. Generalized Projections on Closed Nonconvex Sets in Uniformly Convex and Uniformly Smooth Banach Spaces

    Messaoud Bounkhel

    2015-01-01

    Full Text Available The present paper is devoted to the study of the generalized projection πK:X∗→K, where X is a uniformly convex and uniformly smooth Banach space and K is a nonempty closed (not necessarily convex set in X. Our main result is the density of the points x∗∈X∗ having unique generalized projection over nonempty close sets in X. Some minimisation principles are also established. An application to variational problems with nonconvex sets is presented.

  13. Generalized Projections on Closed Nonconvex Sets in Uniformly Convex and Uniformly Smooth Banach Spaces

    Messaoud Bounkhel

    2015-01-01

    The present paper is devoted to the study of the generalized projection πK:X∗→K, where X is a uniformly convex and uniformly smooth Banach space and K is a nonempty closed (not necessarily convex) set in X. Our main result is the density of the points x∗∈X∗ having unique generalized projection over nonempty close sets in X. Some minimisation principles are also established. An application to variational problems with nonconvex sets is presented.

  14. Applications of fractional calculus to $ k $-uniformly starlike and $ k $-uniformly convex functions of order $ \\alpha $

    Ajab Akbarally

    2007-06-01

    Full Text Available A new subclass of analytic functions $ k-SP_\\lambda(\\alpha $ is introduced by applying certain operators of fractional calculus to $k$-uniformly starlike and $ k $-uniformly convex functions of order $ \\alpha $. Some theorems on coefficient bounds and growth and distortion theorems for this subclass are found. The radii of close to convexity, starlikeness and convexity for this subclass is also derived.

  15. Nanoelectrospray emitter arrays providing interemitter electric field uniformity.

    Kelly, Ryan T; Page, Jason S; Marginean, Ioan; Tang, Keqi; Smith, Richard D

    2008-07-15

    Arrays of electrospray ionization (ESI) emitters have been reported previously as a means of enhancing ionization efficiency or signal intensity. A key challenge when working with multiple, closely spaced ESI emitters is overcoming the deleterious effects caused by electrical interference among neighboring emitters. Individual emitters can experience different electric fields depending on their relative position in the array, such that it becomes difficult to operate all of the emitters optimally for a given applied potential. In this work, we have developed multi-nanoESI emitters arranged with a circular pattern, which enable the constituent emitters to experience a uniform electric field. The performance of the circular emitter array was compared to a single emitter and to a previously developed linear emitter array, which verified that improved electric field uniformity was achieved with the circular arrangement. The circular arrays were also interfaced with a mass spectrometer via a matching multicapillary inlet, and the results were compared with those obtained using a single emitter. By minimizing interemitter electric field inhomogeneities, much larger arrays having closer emitter spacing should be feasible.

  16. Uniform Doping in Quantum-Dots-Based Dilute Magnetic Semiconductor.

    Saha, Avijit; Shetty, Amitha; Pavan, A R; Chattopadhyay, Soma; Shibata, Tomohiro; Viswanatha, Ranjani

    2016-07-01

    Effective manipulation of magnetic spin within a semiconductor leading to a search for ferromagnets with semiconducting properties has evolved into an important field of dilute magnetic semiconductors (DMS). Although a lot of research is focused on understanding the still controversial origin of magnetism, efforts are also underway to develop new materials with higher magnetic temperatures for spintronics applications. However, so far, efforts toward quantum-dots(QDs)-based DMS materials are plagued with problems of phase separation, leading to nonuniform distribution of dopant ions. In this work, we have developed a strategy to synthesize highly crystalline, single-domain DMS system starting from a small magnetic core and allowing it to diffuse uniformly inside a thick CdS semiconductor matrix and achieve DMS QDs. X-ray absorption fine structure (XAFS) spectroscopy and energy-dispersive X-ray spectroscopy-scanning transmission electron microscopy (STEM-EDX) indicates the homogeneous distribution of magnetic impurities inside the semiconductor QDs leading to superior magnetic property. Further, the versatility of this technique was demonstrated by obtaining ultra large particles (∼60 nm) with uniform doping concentration as well as demonstrating the high quality magnetic response.

  17. Improved swimming pool achieves higher reproducibility and sensitivity to effect of food components as ergogenic AIDS.

    Ishihara, Kengo; Yamada, Ayumi; Mita, Yukiko; Goto, Ayako; Ishimi, Tomoe; Mabuchi, Haruko; Inoue, Kazuo; Fushiki, Tohru; Yasumoto, Kyoden

    2009-06-01

    A previously developed current swimming pool for mice has been used to evaluate many food components that enhance endurance exercise performance. In this article, to improve reproducibility, reliability and sensitivity of this assay system, we improved the spout part to generate a uniform current and divided the pool into six lanes to avoid physical interference between swimming mice. The stability of the current flow was assessed by measuring the surface current speed and water volume from the spout part. Maximum swimming times of ddY and BALB/c mice were measured to assess the reproducibility of the maximum swimming time. The improvement in sensitivity compared to the original equipment was estimated under three physiological conditions: low carbohydrate diet feeding, low blood hemoglobin level, and carbohydrate supplementation during exercise. The new spout part improved uniformity and quick adjustment of surface current, yielding an increase of workload in a stepwise manner during swimming. Exercise workload was increased in proportion to surface current speed, as evidenced by cadence of kicks and serum lactic acid levels. The improved swimming pool showed higher reproducibility of swimming time until fatigue (pswimming time was improved in the swimming pool. The improved swimming pool yielded higher sensitivity for low carbohydrate diet feeding (pswimming pool. The improvement of the swimming pool achieved higher sensitivity and reproducibility in assessing various diet and food components compared to the original swimming pool.

  18. Uniform nanoparticles of hydrotalcite-like materials and their textural properties at optimized conditions of urea hydrothermal treatment

    Berber, Mohamed R.; Hafez, Inas H.; Minagawa, Keiji; Katoh, Masahiro; Mori, Takeshi; Tanaka, Masami

    2013-02-01

    The efficient urea hydrothermal synthetic technique for hydrotalcite (HTlc) was optimized to prepare uniform HTlc nanoparticles that exhibit high performance in variety of applications. Experimentally, a series of single-phase Mg-Al HTlc(s) with good textural properties was successfully obtained under optimized urea/metals molar ratio and hydrothermal aging conditions. The X-ray analysis confirmed the purity and the high crystallinity of the prepared HTlc(s). The chemical composition, crystallinity, and textural properties of the optimized HTlc(s) were investigated and compared to those of the conventionally prepared HTlc(s). The increase in the urea concentration decreased the crystallite size of the HTlc(s). The reduction in the hydrothermal aging time led to a narrow particle size distribution. The greatest uniformity of particle size was achieved at a urea/metals molar ratio of 3.0 and at a hydrothermal aging time of 12 h. An increase in the urea/metals molar ratio to 3.0 increased the micropore volume available for adsorption, and the BET surface area consequently increased. The hydrothermal aging of the HTlc(s) significantly decreased the amount of nitrogen the samples adsorbed.

  19. Hot-Volumes as Uniform and Reproducible SERS-Detection Enhancers in Weakly-Coupled Metallic Nanohelices

    Caridad, José M.; Winters, Sinéad; McCloskey, David; Duesberg, Georg S.; Donegan, John F.; Krstić, Vojislav

    2017-01-01

    Reproducible and enhanced optical detection of molecules in low concentrations demands simultaneously intense and homogeneous electric fields acting as robust signal amplifiers. To generate such sophisticated optical near-fields, different plasmonic nanostructures were investigated in recent years. These, however, exhibit either high enhancement factor (EF) or spatial homogeneity but not both. Small interparticle gaps or sharp nanostructures show enormous EFs but no near-field homogeneity. Meanwhile, approaches using rounded and separated monomers create uniform near-fields with moderate EFs. Here, guided by numerical simulations, we show how arrays of weakly-coupled Ag nanohelices achieve both homogeneous and strong near-field enhancements, reaching even the limit forreproducible detection of individual molecules. The unique near-field distribution of a single nanohelix consists of broad hot-spots, merging with those from neighbouring nanohelices in specific array configurations and generating a wide and uniform detection zone (“hot-volume”). We experimentally assessed these nanostructures via surface-enhanced Raman spectroscopy, obtaining a corresponding EF of ~107 and a relative standard deviation <10%. These values demonstrate arrays of nanohelices as state-of-the-art substrates for reproducible optical detection as well as compelling nanostructures for related fields such as near-field imaging. PMID:28358022

  20. Comparison of Turbulent Heat-Transfer Results for Uniform Wall Heat Flux and Uniform Wall Temperature

    Siegel, R.; Sparrow, E. M.

    1960-01-01

    The purpose of this note is to examine in a more precise way how the Nusselt numbers for turbulent heat transfer in both the fully developed and thermal entrance regions of a circular tube are affected by two different wall boundary conditions. The comparisons are made for: (a) Uniform wall temperature (UWT); and (b) uniform wall heat flux (UHF). Several papers which have been concerned with the turbulent thermal entrance region problem are given. 1 Although these analyses have all utilized an eigenvalue formulation for the thermal entrance region there were differences in the choices of eddy diffusivity expressions, velocity distributions, and methods for carrying out the numerical solutions. These differences were also found in the fully developed analyses. Hence when making a comparison of the analytical results for uniform wall temperature and uniform wall heat flux, it was not known if differences in the Nusselt numbers could be wholly attributed to the difference in wall boundary conditions, since all the analytical results were not obtained in a consistent way. To have results which could be directly compared, computations were carried out for the uniform wall temperature case, using the same eddy diffusivity, velocity distribution, and digital computer program employed for uniform wall heat flux. In addition, the previous work was extended to a lower Reynolds number range so that comparisons could be made over a wide range of both Reynolds and Prandtl numbers.

  1. Ultraporous films with uniform nanochannels by block copolymer micelles assembly

    Nunes, Suzana Pereira

    2010-10-12

    Films with high pore density and regularity that are easy to manufacture by conventional large-scale technology are key components aimed for fabrication of new generations of magnetic arrays for storage media, medical scaffolds, and artificial membranes. However, potential manufacture strategies like the self-assembly of block copolymers, which lead to amazing regular patterns, could be hardly reproduced up to now using commercially feasible methods. Here we report a unique production method of nanoporous films based on the self-assembly of copper(II) ion-polystyrene-b-poly(4-vinylpyridine) complexes and nonsolvent induced phase separation. Extremely high pore densities and uniformity were achieved. Water fluxes of 890 L m-2 h-1 bar-1 were obtained, which are at least 1 order of magnitude higher than those of commercially available membranes with comparable pore size. The pores are also stimuli (pH)-responsive. © 2010 American Chemical Society.

  2. Relationships between deformation and microstructure evolution and minimizing surface roughness after BCP processing in RRR Nb cavitites

    T.R. Bieler; D. Baars; K.T. Hartwig; C. Compton; T.L. Grimm

    2009-05-26

    Two strategies for improving the surface finish of niobium sheet used in superconducting radio frequency cavities were examined, using slices of single (or large-grain) material from an ingot, and equal channel angle extrusion (ECAE) preprocessing of ingot material to achieve a uniform and small grain size prior to subsequent rolling. The effect of these two processing paths on final microstructure, texture, and surface finish are discussed.

  3. A comparison of foveated acquisition and tracking performance relative to uniform resolution approaches

    Dubuque, Shaun; Coffman, Thayne; McCarley, Paul; Bovik, A. C.; Thomas, C. William

    2009-05-01

    Foveated imaging has been explored for compression and tele-presence, but gaps exist in the study of foveated imaging applied to acquisition and tracking systems. Results are presented from two sets of experiments comparing simple foveated and uniform resolution targeting (acquisition and tracking) algorithms. The first experiments measure acquisition performance when locating Gabor wavelet targets in noise, with fovea placement driven by a mutual information measure. The foveated approach is shown to have lower detection delay than a notional uniform resolution approach when using video that consumes equivalent bandwidth. The second experiments compare the accuracy of target position estimates from foveated and uniform resolution tracking algorithms. A technique is developed to select foveation parameters that minimize error in Kalman filter state estimates. Foveated tracking is shown to consistently outperform uniform resolution tracking on an abstract multiple target task when using video that consumes equivalent bandwidth. Performance is also compared to uniform resolution processing without bandwidth limitations. In both experiments, superior performance is achieved at a given bandwidth by foveated processing because limited resources are allocated intelligently to maximize operational performance. These findings indicate the potential for operational performance improvements over uniform resolution systems in both acquisition and tracking tasks.

  4. A simple approach to uniform PdAg alloy membranes: Comparative study of conventional and silver concentration-controlled co-plating

    Zeng, Gaofeng

    2014-03-01

    An Ag-controlled co-plating method was developed for the preparation of palladium/silver alloy membranes on porous tubular alumina supports. By controlling the feed rate of Ag to the Pd bath, the concentration of the silver in the plating bath was restricted during the course of plating. As a result, preferential deposition of silver at the beginning was suppressed and uniform dispersion of silver inside the membrane with silver composition in the desired range was achieved. Ultrathin (∼2.5 μm) PdAg alloy membranes with uniform silver composition of ∼25% were successfully obtained. The membrane showed a hydrogen permeance of 0.88 mol m-2 s-1 and pure-gas H2/N2 selectivity of 2140 at 823 K with ΔP = 100 kPa. Only one hydride phase existed in the studied temperature range from 373 to 823 K with ΔPH=100kPa. Direct comparisons with the conventional simply-mixed co-plating method showed that membranes made by the novel Ag-controlled co-plating method had much more uniform silver distribution, smoother surface, denser membrane structure, higher utilization rate of metal sources, and shorter alloying time. © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.

  5. Uniform Foam Crush Testing for Multi-Mission Earth Entry Vehicle Impact Attenuation

    Patterson, Byron W.; Glaab, Louis J.

    2012-01-01

    Multi-Mission Earth Entry Vehicles (MMEEVs) are blunt-body vehicles designed with the purpose of transporting payloads from outer space to the surface of the Earth. To achieve high-reliability and minimum weight, MMEEVs avoid use of limited-reliability systems, such as parachutes and retro-rockets, instead using built-in impact attenuators to absorb energy remaining at impact to meet landing loads requirements. The Multi-Mission Systems Analysis for Planetary Entry (M-SAPE) parametric design tool is used to facilitate the design of MMEEVs and develop the trade space. Testing was conducted to characterize the material properties of several candidate impact foam attenuators to enhance M-SAPE analysis. In the current effort, four different Rohacell foams are tested at three different, uniform, strain rates (approximately 0.17, approximately 100, approximately 13,600%/s). The primary data analysis method uses a global data smoothing technique in the frequency domain to remove noise and system natural frequencies. The results from the data indicate that the filter and smoothing technique are successful in identifying the foam crush event and removing aberrations. The effect of strain rate increases with increasing foam density. The 71-WF-HT foam may support Mars Sample Return requirements. Several recommendations to improve the drop tower test technique are identified.

  6. A practical method for calculating the corrosion rate of uniformly depassivated reinforcing bars in concrete

    Ghods, P.; Isgor, O.B.; Pour-Ghaz, M. [Carleton University, Department of Civil and Environmental Engineering, Mackenzie Engineering Building, Ottawa, K1S 5B6 ON (Canada)

    2007-04-15

    The quantification of active corrosion rate of steel in concrete structures through nondestructive methods is a crucial task for scheduling maintenance/repair operations and for achieving accurate service life predictions. Measuring the polarization resistance of corroding systems and using the Stern-Geary equation to calculate the corrosion current density of active steel is a widely-used method for this purpose. However, these measurements are greatly influenced by environmental factors; therefore, accurate monitoring of corrosion requires integrating the instantaneous corrosion rates over time. Although advanced numerical models are helpful in research settings, they remain to be computationally expensive and complex to be adopted by general engineering community. In this paper, a practical numerical model for predicting corrosion rate of uniformly depassivated steel in concrete is developed. The model is built on Stern's earlier work that an optimum anode-to-cathode ratio exists for which the corrosion current on the metal surface reaches a maximum value. The developed model, which represents the corrosion rate as a function of concrete resistivity and oxygen concentration, is validated using experimental data obtained from the literature. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  7. Code Compliant School Buildings Boost Student Achievement

    Ronald B. Lumpkin

    2014-11-01

    Full Text Available Much of the focus in the literature in raising student achievement has included parental involvement, principal leadership, quality of instruction, students’ socioeconomic status, curriculum, and use of technology. Limited empirical research relates the condition of the school building as a variable that affects student achievement. Furthermore, there is no research that has examined the impact of building codes on achievement outcomes in the state of Florida. This research determined whether academic achievement of 4th-, 8th-, 9th-, and 10th-grade students as measured by the mathematics and reading subtests of the Florida Comprehensive Achievement Test (FCAT increased in new school buildings compliant to the 2000 Florida State Requirements for Educational Facilities. A causal-comparative design determined whether the independent variables, old and new school building influenced student achievement as measured by students’ FCAT mathematics and reading subtest scores. The control group was two cohorts of 4th-, 8th-, 9th-, and 10th-grade students who attended school in old buildings. The experimental group was two cohorts of 4th-, 8th-, 9th-, and 10th-grade students who attended school in new buildings. Transition from an old school into a new school was the treatment. Two hypotheses were formulated for testing and the research question for the inquiry was whether the percentage of students passing the FCAT mathematics and reading subtests increases after transitioning from an old school building into a new 2000 UBC (Uniform Building Code compliant facility.

  8. Elastic deformations driven by non-uniform lubrication flows

    Rubin, Shimon; Gat, Amir; Bercovici, Moran

    2016-01-01

    The ability to create dynamic deformations of micron-sized structures is relevant to a wide variety of applications such as adaptable optics, soft robotics, and reconfigurable microfluidic devices. In this work we examine non-uniform lubrication flow as a mechanism to create complex deformation fields in an elastic plate. We consider a Kirchoff-Love elasticity model for the plate and Hele-Shaw flow in a narrow gap between the plate and a parallel rigid surface. Based on linearization of the Reynolds equation, we obtain a governing equation which relates elastic deformations to gradients in non-homogenous physical properties of the fluid (e.g. body forces, viscosity, and slip velocity). We then focus on a specific case of non-uniform Helmholtz-Smoluchowski electroosmotic slip velocity, and provide a method for determining the zeta-potential distribution necessary to generate arbitrary static and quasi-static deformations of the elastic plate. Extending the problem to time-dependent solutions, we analyze transi...

  9. Elastic deformations driven by non-uniform lubrication flows

    Rubin, Shimon; Tulchinsky, Arie; Gat, Amir D.; Bercovici, Moran

    2017-02-01

    The ability to create dynamic deformations of micron-sized structures is relevant to a wide variety of applications such as adaptable optics, soft robotics, and reconfigurable microfluidic devices. In this work we examine non-uniform lubrication flow as a mechanism to create complex deformation fields in an elastic plate. We consider a Kirchoff-Love elasticity model for the plate and Hele-Shaw flow in a narrow gap between the plate and a parallel rigid surface. Based on linearization of the Reynolds equation, we obtain a governing equation which relates elastic deformations to gradients in non-homogenous physical properties of the fluid (e.g. body forces, viscosity, and slip velocity). We then focus on a specific case of non-uniform Helmholtz-Smoluchowski electroosmotic slip velocity, and provide a method for determining the zeta-potential distribution necessary to generate arbitrary static and quasi-static deformations of the elastic plate. Extending the problem to time-dependent solutions, we analyze transient effects on asymptotically static solutions, and finally provide a closed form solution for a Green's function for time periodic actuations.

  10. Uniform Approximation of Vapnik-Chervonenkis Classes

    Adams, Terrence M

    2010-01-01

    For any family of measurable sets in a probability space, we show that either (i) the family has infinite Vapnik-Chervonenkis (VC) dimension or (ii) for every epsilon > 0 there is a finite partition pi such the pi-boundary of each set has measure at most epsilon. Immediate corollaries include the fact that a family with finite VC dimension has finite bracketing numbers, and satisfies uniform laws of large numbers for every ergodic process. From these corollaries, we derive analogous results for VC major and VC graph families of functions.

  11. Radiative processes of uniformly accelerated entangled atoms

    Menezes, G

    2015-01-01

    We study radiative processes of uniformly accelerated entangled atoms, interacting with an electromagnetic field prepared in the Minkowski vacuum state. We discuss the structure of the rate of variation of the atomic energy for two atoms travelling in different hyperbolic world lines. We identify the contributions of vacuum fluctuations and radiation reaction to the generation of entanglement as well as to the decay of entangled states. Our results resemble the situation in which two inertial atoms are coupled individually to two spatially separated cavities at different temperatures. In addition, for equal accelerations we obtain that the maximally entangled antisymmetric Bell state is a decoherence-free state.

  12. Weak, strong, and uniform quantum simulations

    Wang, Dong-Sheng

    2015-01-01

    In this work, we introduce different types of quantum simulations according to different operator topologies on a Hilbert space, namely, uniform, strong, and weak quantum simulations. We show that they have the same computational power that the efficiently solvable problems are in bounded-error quantum polynomial time. For the weak simulation, we formalize a general weak quantum simulation problem and construct an algorithm which is valid for all instances. Also, we analyze the computational power of quantum simulations by proving the query lower bound for simulating a general quantum process.

  13. Quantum Radiation of Uniformly Accelerated Spherical Mirrors

    Frolov, V

    2001-01-01

    We study quantum radiation generated by a uniformly accelerated motion of small spherical mirrors. To obtain Green's function for a scalar massless field we use Wick's rotation. In the Euclidean domain the problem is reduced to finding an electric potential in 4D flat space in the presence of a metallic toroidal boundary. The latter problem is solved by a separation of variables. After performing an inverse Wick's rotation we obtain the Hadamard function in the wave-zone regime and use it to calculate the vacuum fluctuations and the vacuum expectation for the energy density flux in the wave zone.

  14. Quantum Electrodynamics in a Uniform Magnetic Field

    Suzuki, J

    2005-01-01

    A systematic formalism for quantum electrodynamics in a classical uniform magnetic field is discussed. The first order radiative correction to the ground state energy of an electron is calculated. This then leads to the anomalous magnetic moment of an electron without divergent integrals. Thorough analyses of this problem are given for the weak magnetic field limit. A new expression for the radiative correction to the ground state energy is obtained. This contains only one integral with an additional summation with respect to each Landau level. The importance of this formalism is also addressed in order to deal with quantum electrodynamics in an intense external field.

  15. Uniformity and control in the pyrotechnic environment

    Strubel, S. J. [Harvard Industries Inc., Arnold, MO (United States)

    2000-04-01

    In the production of pyrotechnic materials control is very stringent as dictated by the intrinsic nature of the material. Uniformity is continuous and maintained at a high level. In contrast, once the pyrotechnic material is produced susceptibility towards loss in control begins, given the multiplicity of destination, environmental changes, storage, terrain shooting devices, ignition methods, non-standard state regulations and variations in safety personnel expertise. This author claims that with the advances made in electronic engineering, adoption of electronic control systems could greatly increase uniformity and control. Some of his recommendations include: electronic consoles designed with computers for firing control, choreography and animated lighting displays; microchips embedded in pyrotechnic materials for ease of identification, storage, transportation and display; microchips encased in flash technology to provide ignition, replacing chemical fuses; audible alarms and light signals to alert the operator when the fireworks device is moved to the arming stage, thus preventing inadvertent firing; and electronic sequencers for firing mortars, in one launcher, milliseconds apart, to lessen the impact on launchers. Benefits claimed for these techniques would be increased safety, reduced insurance premiums and claims, and increase in efficiency and most of all, in control.

  16. Branching structure of uniform recursive trees

    FENG; Qunqiang; SU; Chun; HU; Zhishui

    2005-01-01

    The branching structure of uniform recursive trees is investigated in this paper.Using the method of sums for a sequence of independent random variables, the distribution law of ηn, the number of branches of the uniform recursive tree of size n are given first. It is shown that the strong law of large numbers, the central limit theorem and the law of iterated logarithm for ηn follow easily from this method. Next it is shown that ηn and ξn, the depth of vertex n, have the same distribution, and the distribution law of ζn,m, the number of branches of size m, is also given, whose asymptotic distribution is the Poisson distribution with parameter λ = 1/m. In addition, the joint distribution and the asymptotic joint distribution of the numbers of various branches are given. Finally, it is proved that the size of the biggest branch tends to infinity almost sure as n -→∞.

  17. Lang's conjectures, conjecture H, and uniformity

    Abramovich, D

    1995-01-01

    The purpose of this note is to wish a happy birthday to Professor Lucia Caporaso.* We prove that Conjecture H of Caporaso et. al. ([CHarM], sec. 6) together with Lang's conjecture implies the uniformity of rational points on varieties of general type, as predicted in [CHarM]; a few applications in arithmetic and geometry are stated. Let X be a variety of general type defined over a number field K. It was conjectured by S. Lang that the set of rational points X(K) is not Zariski dense in X. In the paper [CHarM] of L. Caporaso, J. Harris and B. Mazur it is shown that the above conjecture of Lang implies the existence of a uniform bound on the number of K-rational points of all curves of fixed genus g over K. The paper [CHarM] has immediately created a chasm among arithmetic geometers. This chasm, which often runs right in the middle of the personalities involved, divides between loyal believers of Lang's conjecture, who marvel in this powerful implication, and the disbelievers, who try (so far in vain) to use t...

  18. Uniformly accelerated observer in a thermal bath

    Kolekar, Sanved

    2013-01-01

    We investigate the quantum field aspects in flat spacetime for an uniformly accelerated observer moving in a thermal bath. In particular, we obtain an exact closed expression of the reduced density matrix for an uniformly accelerated observer with acceleration $a = 2\\pi T$ when the state of the quantum field is a thermal bath at temperature $T^\\prime$. We find that the density matrix has a simple form with an effective partition function $Z$ being a product, $Z = Z_T Z_{T^\\prime}$, of two thermal partition functions corresponding to temperatures $T$ and $T^\\prime$ and hence is not thermal, even when $T = T^\\prime$. We show that, even though the partition function has a product structure, the two thermal baths are, in fact, interacting systems; although in the high frequency limit $\\omega_k \\gg T$ and $\\omega_k \\gg T^\\prime$, the interactions are found to become sub-dominant. We further demonstrate that the resulting spectrum of the Rindler particles can be interpreted in terms of spontaneous and stimulated em...

  19. Uniformity of measures with Fourier frames

    Dutkay, Dorin Ervin

    2012-01-01

    We examine Fourier frames and, more generally, frame measures for different probability measures. We prove that if a measure has an associated frame measure, then it must have a certain uniformity in the sense that the weight is distributed quite uniformly on its support. To be more precise, by considering certain absolute continuity properties of the measure and its translation, we recover the characterization on absolutely continuous measures $g\\, dx$ with Fourier frames obtained in \\cite{Lai11}. Moreover, we prove that the frame bounds are pushed away by the essential infimum and supremum of the function $g$. This also shows that absolutely continuous spectral measures supported on a set $\\Omega$, if they exist, must be the standard Lebesgue measure on $\\Omega$ up to a multiplicative constant. We then investigate affine iterated function systems (IFSs), we show that if an IFS with no overlap admits a frame measure then the probability weights are all equal. Moreover, we also show that the {\\L}aba-Wang conj...

  20. A quality index for equivalent uniform dose

    Henríquez, Francisco Cutanda; Castrillón, Silvia Vargas

    2011-01-01

    Equivalent uniform dose (EUD) is the absorbed dose that, when homogeneously given to a tumor, yields the same mean surviving clonogen number as the given non-homogeneous irradiation. EUD is used as an evaluation tool under the assumption that two plans with the same value of EUD are equivalent, and their biological effect on the tumor (clonogen survival) would be the same as the one of a homogeneous irradiation of absorbed dose EUD. In this work, this assumption has been studied, and a figure of merit of its applicability has been obtained. Distributions of surviving clonogen number for homogeneous and non-homogeneous irradiations are found to be different even if their mean values are the same, the figure of merit being greater when there is a wider difference, and the equivalence assumption being less valid. Therefore, EUD can be closer to a uniform dose for some cases than for other ones (high α values, extreme heterogeneity), and the accuracy of the radiobiological indices obtained for evaluation, could be affected. Results show that the equivalence is very sensitive to the choice of radiobiological parameters, and this conclusion has been derived from mathematical properties of EUD. PMID:21897557

  1. Spinning Janus doublets driven in uniform AC electric fields

    Boymelgreen, Alicia; Park, Sinwook; Miloh, Touvia

    2013-01-01

    We provide an experimental proof-of-concept for a robust, continuously rotating microstructure - consisting of two metallodielectric (gold-polystyrene)Janus particles rigidly attached to each other - which is driven in uniform ac fields by asymmetric induced-charge electroosmosis. The pairs (doublets) are stabilized on the substrate surface which is parallel to the plane of view and normal to the direction of the applied electric field. We find that the radius of orbit and angular velocity of the pair are predominantly dependent on the relative orientations of the interfaces between the metallic and dielectric hemispheres and that the electrohydrodynamic particle-particle interactions are small. Additionally, we verify that both the angular and linear velocities of the pair are proportional to the square of the applied field which is consistent with the theory for non-linear electrokinetics. A simple kinematic rigid body model is used to predict the paths and double velocities (angular and linear) based on th...

  2. Instabilities of uniform filtration flows with phase transition

    Il'Ichev, A. T.; Tsypkin, G. G.

    2008-10-01

    New mechanisms of instability are described for vertical flows with phase transition through horizontally extended two-dimensional regions of a porous medium. A plane surface of phase transition becomes unstable at an infinitely large wavenumber and at zero wavenumber. In the latter case, the unstable flow undergoes reversible subcritical bifurcations leading to the development of secondary flows (which may not be horizontally uniform). The evolution of subcritical modes near the instability threshold is governed by the Kolmogorov-Petrovskii-Piskunov equation. Two examples of flow through a porous medium are considered. One is the unstable flow across a water-bearing layer above a layer that carries a vapor-air mixture under isothermal conditions in the presence of capillary forces at the phase transition interface. The other is the vertical flow with phase transition in a high-temperature geothermal reservoir consisting of two high-permeability regions separated by a low-permeability stratum.

  3. Test stand for non-uniformity correction of microbolometer focal plane arrays used in thermal cameras

    Krupiński, Michał; Bareła, Jaroslaw; Firmanty, Krzysztof; Kastek, Mariusz

    2013-10-01

    Uneven response of particular detectors (pixels) to the same incident power of infrared radiation is an inherent feature of microbolometer focal plane arrays. As a result an image degradation occurs, known as Fixed Pattern Noise (FPN), which distorts the thermal representation of an observed scene and impairs the parameters of a thermal camera. In order to compensate such non-uniformity, several NUC correction methods are applied in digital data processing modules implemented in thermal cameras. Coefficients required to perform the non-uniformity correction procedure (NUC coefficients) are determined by calibrating the camera against uniform radiation sources (blackbodies). Non-uniformity correction is performed in a digital processing unit in order to remove FPN pattern in the registered thermal images. Relevant correction coefficients are calculated on the basis of recorded detector responses to several values of radiant flux emitted from reference IR radiation sources (blackbodies). The measurement of correction coefficients requires specialized setup, in which uniform, extended radiation sources with high temperature stability are one of key elements. Measurement stand for NUC correction developed in Institute of Optoelectronics, MUT, comprises two integrated extended blackbodies with the following specifications: area 200×200 mm, stabilized absolute temperature range +15 °C÷100 °C, and uniformity of temperature distribution across entire surface +/-0.014 °C. Test stand, method used for the measurement of NUC coefficients and the results obtained during the measurements conducted on a prototype thermal camera will be presented in the paper.

  4. Hawking Radiation of Dirac Particles on Rindler Horizon to a Uniformly Accelerating Observer

    ZHANGJinK-Yi

    2003-01-01

    Following the method of Damour and Ruffini, the Hawking radiation of Dirac particles on Rindler horison to a uniformly accelerating observer is studied this paper. The temperature on Rindler horizon surface and the thermal spectrum formula of Dirac particles are obtained. The result is discussed.

  5. Hawking Radiation of Dirac Particles on Rindler Horizon to a Uniformly Accelerating Observer

    ZHANG Jing-Yi

    2003-01-01

    Following the method of Damour and Ruffini, the Hawking radiation of Dirac particles on Rindler horizonto a uniformly accelerating observer is studied in this paper. The temperature on Rindler horizon surface and the thermalspectrum formula of Dirac particles are obtained. The result is discussed.

  6. On Heat Transfer through a Solid Slab Heated Uniformly and Periodically: Determination of Thermal Properties

    Rojas-Trigos, J. B.; Bermejo-Arenas, J. A.; Marin, E.

    2012-01-01

    In this paper, some heat transfer characteristics through a sample that is uniformly heated on one of its surfaces by a power density modulated by a periodical square wave are discussed. The solution of this problem has two contributions, comprising a transient term and an oscillatory term, superposed to it. The analytical solution is compared to…

  7. A Computer Method of Steady Non-Uniform Gradually Varied Flow in Open Channel & in River

    1999-01-01

    Most of water flow in open channel or in river belongs to steady non-uniform flow. The surface profiles are caused by changes of channel section. It is very important to analyze its computation. According to the regularity of its surface change, the suitable sectional dimensions of open channel or flood control work can be designed. Commonly, computation of non-uniform flow adopts the traditional methods by hand or by graphic method. The speed and precision of computation are restricted. In this paper, a software to calculate water surface profile is introduced. The software is put forward by using C++ .By means of interpolate method and dialogue between user and computer, we can calculate the water surface profile much more quickly and exactly.

  8. Uniform Consistency for Nonparametric Estimators in Null Recurrent Time Series

    Gao, Jiti; Kanaya, Shin; Li, Degui;

    2015-01-01

    This paper establishes uniform consistency results for nonparametric kernel density and regression estimators when time series regressors concerned are nonstationary null recurrent Markov chains. Under suitable regularity conditions, we derive uniform convergence rates of the estimators. Our...

  9. Complex locally uniform rotundity of Musielak-Orlicz spaces

    2000-01-01

    The concepts of complex locally uniform rotundity and complex locally uniformly rotund point are introduced. The sufficient and necessary conditions of them are given in complex Musielak-Orlicz spaces.

  10. NCLB: Achievement Robin Hood?

    Bracey, Gerald W.

    2008-01-01

    In his "Wall Street Journal" op-ed on the 25th of anniversary of "A Nation At Risk", former assistant secretary of education Chester E. Finn Jr. applauded the report for turning U.S. education away from equality and toward achievement. It was not surprising, then, that in mid-2008, Finn arranged a conference to examine the…

  11. Cognitive Processes and Achievement.

    Hunt, Dennis; Randhawa, Bikkar S.

    For a group of 165 fourth- and fifth-grade students, four achievement test scores were correlated with success on nine tests designed to measure three cognitive functions: sustained attention, successive processing, and simultaneous processing. This experiment was designed in accordance with Luria's model of the three functional units of the…

  12. Uniform Approximation and Bracketing Properties of VC classes

    Adams, Terrence M

    2010-01-01

    We show that the sets in a family with finite VC dimension can be uniformly approximated within a given error by a finite partition. Immediate corollaries include the fact that VC classes have finite bracketing numbers, satisfy uniform laws of averages under strong dependence, and exhibit uniform mixing. Our results are based on recent work concerning uniform laws of averages for VC classes under ergodic sampling.

  13. Uniform bases at non-isolated points and maps

    Lin, Fucai

    2011-01-01

    In this paper, the authors mainly discuss the images of spaces with an uniform base at non-isolated points, and obtain the following main results: (1)\\ Perfect maps preserve spaces with an uniform base at non-isolated points; (2)\\ Open and closed maps preserve regular spaces with an uniform base at non-isolated points; (3)\\ Spaces with an uniform base at non-isolated points don't satisfy the decomposition theorem.

  14. Liouville theory and uniformization of four-punctured sphere

    Hadasz, L; Hadasz, Leszek; Jaskolski, Zbigniew

    2006-01-01

    Few years ago Zamolodchikov and Zamolodchikov proposed an expression for the 4-point classical Liouville action in terms of the 3-point actions and the classical conformal block. In this paper we develop a method of calculating the uniformizing map and the uniformizing group from the classical Liouville action on n-punctured sphere and discuss the consequences of Zamolodchikovs conjecture for an explicit construction of the uniformizing map and the uniformizing group for the sphere with four punctures.

  15. Large-area, uniform white light LED source on a flexible substrate.

    Sher, Chin-Wei; Chen, Kuo-Ju; Lin, Chien-Chung; Han, Hau-Vei; Lin, Huang-Yu; Tu, Zong-Yi; Tu, Hsien-Hao; Honjo, Keiji; Jiang, Hsin-Yi; Ou, Sin-Liang; Horng, Ray-Hua; Li, Xiuling; Fu, Chien-Chung; Kuo, Hao-Chung

    2015-09-21

    This study demonstrates the flexible white LED structure with high lumen efficiency and uniform optical performance for neutral white and warm white CCT. Flip-chip LEDs were attached on a polyimide substrate with copper strips as electrical and thermal conduction paths. Yellow phosphors are mixed with polydimenthysiloxane (PDMS) to provide mechanical support and flexibility. The light efficiency of this device can reach 120 lm/W and 85% of light output uniformity of the emission area can be achieved. Moreover, the optical simulation is employed to evaluate various designs of this flexible film in order to obtain uniform output. Both the pitch between the individual devices and the thickness of the phosphor film are calculated for optimization purpose. This flexible white LED with high lumen efficiency and good reliability is suitable for the large area fixture in the general lighting applications.

  16. 24 CFR 5.801 - Uniform financial reporting standards.

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false Uniform financial reporting... and Urban Development GENERAL HUD PROGRAM REQUIREMENTS; WAIVERS Uniform Financial Reporting Standards § 5.801 Uniform financial reporting standards. (a) Applicability. This subpart H implements...

  17. Uniform stability of displacement coupled second-order equations

    Abdelaziz Soufyane

    2001-04-01

    Full Text Available We prove that the uniform stability of semigroups associated to displacement coupled dissipator systems is equivalent to the uniform stability of velocity coupled dissipator systems. Using this equivalence, we give sufficient conditions for obtaining uniform stability and exact controllability of displacement coupled dissipator systems.

  18. Locally uniformly convex norms in Banach spaces and their duals

    Haydon, Richard

    2006-01-01

    It is shown that a Banach space with locally uniformly convex dual admits an equivalent norm which is itself locally uniformly convex. It follows that on any such space all continuous real-valued functions may be uniformly approximated by C^1 functions.

  19. Beyond Fashion Patrol: School Uniforms in the Middle Grades.

    Kommer, David

    1999-01-01

    Discusses the benefits of school uniforms in fulfilling the educational objectives of middle school reform. Considers the role of uniforms in establishing student affiliation with the school and in adolescent development. Describes the development of a uniform program and notes issues of cost and legality. (JPB)

  20. Reflector Design Method for Rotational Uniform Illuminance System with LED

    ZHANG Qi-hui; WANG Hong; JI Ling-ling

    2009-01-01

    Based on nonimaging design method,uniform illuminance systems with LED source were developed to create a uniform illuminated circular region with a desired size in a screen at a prescribed place.By using ray-tracing software based on Monte-Carlo method,the simulation results show that in the illuminated region the luminous uniformity is higher than 90%.

  1. Quantitative multi-pinhole small-animal SPECT : uniform versus non-uniform Chang attenuation correction

    Wu, C.; de Jong, J. R.; van Andel, H. A. Gratama; van der Have, F.; Vastenhouw, B.; Laverman, P.; Boerman, O. C.; Dierckx, R. A. J. O.; Beekman, F. J.

    2011-01-01

    Attenuation of photon flux on trajectories between the source and pinhole apertures affects the quantitative accuracy of reconstructed single-photon emission computed tomography (SPECT) images. We propose a Chang-based non-uniform attenuation correction (NUA-CT) for small-animal SPECT/CT with focusi

  2. Quantitative multi-pinhole small-animal SPECT: uniform versus non-uniform Chang attenuation correction

    Wu, C.; Jong, J.R. de; Gratama van Andel, H.A.; Have, F. van der; Vastenhouw, B.; Laverman, P.; Boerman, O.C.; Dierckx, R.A.; Beekman, F.J.

    2011-01-01

    Attenuation of photon flux on trajectories between the source and pinhole apertures affects the quantitative accuracy of reconstructed single-photon emission computed tomography (SPECT) images. We propose a Chang-based non-uniform attenuation correction (NUA-CT) for small-animal SPECT/CT with focusi

  3. Politicas de uniformes y codigos de vestuario (Uniforms and Dress-Code Policies). ERIC Digest.

    Lumsden, Linda

    This digest in Spanish examines schools' dress-code policies and discusses the legal considerations and research findings about the effects of such changes. Most revisions to dress codes involve the use of uniforms, typically as a way to curb school violence and create a positive learning environment. A recent survey of secondary school principals…

  4. Uniform Effects?: Schools Cite Benefits of Student Uniforms, but Researchers See Little Evidence of Effectiveness

    Viadero, Debra

    2005-01-01

    This article reports on the effectiveness of school uniform policies. At Stephen Decatur Middle School, it is the school's policy that all students wear the standard school attire consisting of khaki pants with polo shirts in white, burgundy, or navy blue. Some of the shirts also sport an embroidered Decatur eagle, an optional embellishment.…

  5. Uniform trigonometric polynomial B-spline curves

    吕勇刚; 汪国昭; 杨勋年

    2002-01-01

    This paper presents a new kind of uniform spline curve, named trigonometric polynomialB-splines, over space Ω = span{sint, cost, tk-3,tk-4,…,t,1} of which k is an arbitrary integerlarger than or equal to 3. We show that trigonometric polynomial B-spline curves have many similarV properties to traditional B-splines. Based on the explicit representation of the curve we have also presented the subdivision formulae for this new kind of curve. Since the new spline can include both polynomial curves and trigonometric curves as special cases without rational form, it can be used as an efficient new model for geometric design in the fields of CAD/CAM.

  6. Uniform diet in a diverse society

    Jørkov, Marie Louise Schjellerup; Jørgensen, Lars; Lynnerup, Niels

    2010-01-01

    A systematic dietary investigation during Danish Roman Iron Age (1-375AD) is conducted by analyzing stable isotope ratios of carbon (delta(13)C) and nitrogen (delta(15)N) in the collagen of human and animal bone. The human sample comprises 77 individuals from 10 burial sites. In addition 31 samples...... on social structure and subsistence economy in both the Early and Late Period. Geographically the locations are both inland and coastal. The isotopic data indicate extremely uniform diet both between and within population groups from Early and Late Roman periods and the data are consistent throughout...... been important, even among the individuals living next to the coast. Am J Phys Anthropol, 2010. (c) 2010 Wiley-Liss, Inc....

  7. Designing divertor targets for uniform power load

    Dekeyser, W.; Reiter, D.; Baelmans, M.

    2015-08-01

    Divertor design for next step fusion reactors heavily relies on 2D edge plasma modeling with codes as e.g. B2-EIRENE. While these codes are typically used in a design-by-analysis approach, in previous work we have shown that divertor design can alternatively be posed as a mathematical optimization problem, and solved very efficiently using adjoint methods adapted from computational aerodynamics. This approach has been applied successfully to divertor target shape design for more uniform power load. In this paper, the concept is further extended to include all contributions to the target power load, with particular focus on radiation. In a simplified test problem, we show the potential benefits of fully including the radiation load in the design cycle as compared to only assessing this load in a post-processing step.

  8. Frames of most uniform Hubble flow

    Kraljic, David

    2016-01-01

    It has been observed that the locally measured Hubble parameter converges quickest to the background value and the dipole structure of the velocity field is smallest in the reference frame of the Local Group of galaxies. We study the statistical properties of Lorentz boosts with respect to the Cosmic Microwave Background frame which make the Hubble flow look most uniform around a particular observer. We use a very large N-Body simulation to extract the dependence of the boost velocities on the local environment such as underdensities, overdensities, and bulk flows. We find that the observation is not unexpected if we are located in an underdensity, which is indeed the case for our position in the universe. The amplitude of the measured boost velocity for our location is consistent with the expectation in the standard cosmology.

  9. Outer commutator words are uniformly concise

    Fernández-Alcober, Gustavo A

    2009-01-01

    We prove that outer commutator words are uniformly concise, i.e. if an outer commutator word w takes m different values in a group G, then the order of the verbal subgroup w(G) is bounded by a function depending only on m and not on w or G. This is obtained as a consequence of a structure theorem for the subgroup w(G), which is valid if G is soluble, and without assuming that w takes finitely many values in G. More precisely, there is an abelian series of w(G), such that every section of the series can be generated by values of w all of whose powers are also values of w in that section. For the proof of this latter result, we introduce a new representation of outer commutator words by means of binary trees, and we use the structure of the trees to set up an appropriate induction.

  10. Non-Uniformity and Generalised Sacks Splitting

    COOPER S.Barry; LI Ang Sheng

    2002-01-01

    We show that there do not exist computable functions f1(e, i), f2 (e, i), g1(e, i), g2(e, i) such that for all e, i ∈ω,(1) (Wf1(e,i) - Wf2(e,i)) ≤T (We - Wi);(2) (Wg1(e,i) - Wg2(e,i))≤T (We - Wi);(3) (We - Wi) ≤T (Wf1(e,i) - Wf2(e,i)) (Wg1(e,i) - Wg2(e,i));(4) (We - Wi) T (Wf1(e,i) - Wf2(e,i)) unless (We - Wi) ≤T ; and (5) (We - Wi) T (Wg1(e,i) - Wg2(e,i)) unless (We - Wi) ≤T .It follows that the splitting theorems of Sacks and Cooper cannot be combined uniformly.

  11. Concentration uniformity of extemporaneously prepared ranitidine suspension.

    Karnes, H T; Harris, S R; Garnett, W R; March, C

    1989-02-01

    The concentration uniformity of an extemporaneously prepared ranitidine suspension was studied. To prepare the ranitidine suspension, 36 150-mg tablets were pulverized and suspended in 180 mL of distilled water. This mixture was diluted with simple syrup to a total volume of 360 mL, resulting in a final ranitidine concentration of 150 mg/10 mL. Samples from each of three bottles that had been filled with 60 mL of the suspension were assayed for ranitidine content by high-performance liquid chromatography. The sedimentation of suspended ranitidine tablet particles was studied by visual observation of the setting process in 10-mL samples from the same batch. The overall mean concentrations (in milligrams per milliliter) of ranitidine were 14.53, 15.25, 13.92, 12.67, and 12.72 at 0, 3, 7, 14, and 21 days, respectively. Compared with baseline, the difference in the ranitidine concentration was not significant over days 0-7. The ranitidine concentration was significantly reduced during the following time intervals: days 0-14, days 0-21, and days 7-21. In the settling experiments, the mean time (+/- S.D.) for sediment to first appear on the test tube bottom was 14.67 +/- 5.35 seconds. Approximately 40-50% (mean level = 3.2 mm) of the total sedimentation level (mean level = 7.3 mm) was observed one minute after shaking. The uniformity of ranitidine suspensions compounded according to procedures described in this report possibly could be improved with sonication. The ranitidine suspension should be well shaken, the dosage should be measured immediately after shaking, and the suspension should be used within seven days of compounding.

  12. Uniformity Tests in Circular Data: Review

    Ismet DOGAN

    2015-10-01

    Full Text Available Circular data are a large class of directional data, which are interest in many fields. Examples include phenomena that are periodic in time, including those dependent on hours of the day (hospital visits, times of birth, etc. or days of the year (unemployment or sales variations. The elementary but also fundamental property of circular data is that the beginning and end of the scale coincide: for example, 0° = 360°. An immediate implication is that the arithmetic mean is likely to be a poor summary: the mean of 1° and 359° cannot sensibly be 180°. The solution is use the vector mean direction as circular mean. The statistical analysis of angular or circular data differs from the analysis of linear data. Unlike linear distributions, which are often two-tailed and infinite, circular distributions exhibit finite closure because a circular data set comes back on itself, and therefore, 0° and 360° are actually the same point on a circle. Circular statistics is concerned mainly with observations which are unit vectors in the plane. Thus the sample space is typically a circle or a sphere, so that standart methods for analysing univariate or multivariate measurement data can?t be used. Special circular methods are required take into account the structure of these sample spaces. In most circular statistical analyses, the null hypothesis is a uniform distribution in which all directions occur with equal probability. In this study, eight different testing methods improved for uniformity in angular data have been introduced and these methods were compared with each other by using the information obtained from the literature.

  13. Dynamic thermoelectricity in uniform bipolar semiconductor

    Volovichev, I.N., E-mail: vin@ire.kharkov.ua

    2016-07-01

    The theory of the dynamic thermoelectric effect has been developed. The effect lies in an electric current flowing in a closed circuit that consists of a uniform bipolar semiconductor, in which a non-uniform temperature distribution in the form of the traveling wave is created. The calculations are performed for the one-dimensional model in the quasi-neutrality approximation. It was shown that the direct thermoelectric current prevails, despite the periodicity of the thermal excitation, the circuit homogeneity and the lack of rectifier properties of the semiconductor system. Several physical reasons underlining the dynamic thermoelectric effect are found. One of them is similar to the Dember photoelectric effect, its contribution to the current flowing is determined by the difference in the electron and hole mobilities, and is completely independent of the carrier Seebeck coefficients. The dependence of the thermoelectric short circuit current magnitude on the semiconductor parameters, as well as on the temperature wave amplitude, length and velocity is studied. It is shown that the magnitude of the thermoelectric current is proportional to the square of the temperature wave amplitude. The dependence of the thermoelectric short circuit current on the temperature wave length and velocity is the nonmonotonic function. The optimum values for the temperature wave length and velocity, at which the dynamic thermoelectric effect is the greatest, have been deduced. It is found that the thermoelectric short circuit current changes its direction with decreasing the temperature wave length under certain conditions. The prospects for the possible applications of the dynamic thermoelectric effect are also discussed.

  14. Superhydrophobic Behavior on Nano-structured Surfaces

    Schaeffer, Daniel

    2008-05-01

    Superhydrophobic behavior is observed in natural occurrences and has been thoroughly studied over the past few years. Water repellant properties on uniform arrays of vertically aligned nano-cones were investigated to determine the highest achievable contact angle (a measure of water drop repellency), which is measured from the reference plane on which the water drop sits to the tangent line of the point at which the drop makes contact with the reference plane. At low aspect ratios (height vs. width of the nano-cones), surface tension pulls the water into the nano-cone array, resulting in a wetted surface. Higher aspect ratios reverse the effect of the surface tension, resulting in a larger contact angle that causes water drops to roll off the surface. Fiber drawing, bundling, and redrawing are used to produce the structured array glass composite surface. Triple-drawn fibers are fused together, annealed, and sliced into thin wafers. The surface of the composite glass is etched to form nano-cones through a differential etching process and then coated with a fluorinated self-assembled monolayer (SAM). Cone aspect ratios can be varied through changes in the chemistry and concentration of the etching acid solution. Superhydrophobic behavior occurs at contact angles >150 and it is predicted and measured that optimal behavior is achieved when the aspect ratio is 4:1, which displays contact angles >=175 .

  15. Achieving Small World Properties using Bio-Inspired Techniques in Wireless Networks

    Agarwal, Rachit; Gauthier, Vincent; Becker, Monique; Yeo, Chai Kiat; Lee, Bu Sung

    2011-01-01

    Self-Organization properties of the nodes play an important role in an autonomous wireless sensor environment in achieving network wide characteristics. Self-Organization can be used to achieve small world characteristics in a network. In real networks, however, where there is non-uniform distribution of nodes and overall connectivity of the network is less, achieving small world properties while increasing connectivity must be studied. We believe that network connectivity can be increased and small world properties can be achieved with the help of beamforming, biologically inspired algorithms and using local information. Most of the researches performed in direction of achieving above mentioned goals in wireless networks assume knowledge of network with either heterogeneous or hybrid uniform deployment. We propose that without the knowledge of the global environment or introduction of any special features in the network, we can achieve our goal with the help of inspirations from the nature in a non-uniform n...

  16. Achieveing Organizational Excellence Through

    Mehdi Abzari

    2009-04-01

    Full Text Available AbstractToday, In order to create motivation and desirable behavior in employees, to obtain organizational goals,to increase human resources productivity and finally to achieve organizational excellence, top managers oforganizations apply new and effective strategies. One of these strategies to achieve organizational excellenceis creating desirable corporate culture. This research has been conducted to identify the path to reachorganizational excellence by creating corporate culture according to the standards and criteria oforganizational excellence. The result of the so-called research is this paper in which researchers foundtwenty models and components of corporate culture and based on the Industry, organizational goals andEFQM model developed a model called "The Eskimo model of Culture-Excellence". The method of theresearch is survey and field study and the questionnaires were distributed among 116 managers andemployees. To assess the reliability of questionnaires, Cronbach alpha was measured to be 95% in the idealsituation and 0/97 in the current situation. Systematic sampling was done and in the pre-test stage 45questionnaires were distributed. A comparison between the current and the ideal corporate culture based onthe views of managers and employees was done and finally it has been concluded that corporate culture isthe main factor to facilitate corporate excellence and success in order to achieve organizational effectiveness.The contribution of this paper is that it proposes a localized –applicable model of corporate excellencethrough reinforcing corporate culture.

  17. Compression gain of spin wave signals in a magnonic YIG waveguide with thermal non-uniformity

    Kolokoltsev, O.; Gómez-Arista, Ivan; Qureshi, N.; Acevedo, A.; Ordóñez-Romero, César L.; Grishin, A.

    2015-03-01

    We report on the observation of the compression gain of the signals carried by surface spin waves (MSSWs) in yittrium iron garnet films as a result of non-uniform optical heating of the spin wave medium. Efficient gain takes place if a frequency downshift of the spin wave spectrum induced by the heating is compensated by the corresponding non-uniformity of the bias magnetic field. It is proposed that the effect can be understood in part as an interaction between spin waves and a thermally induced potential well in the sample.

  18. Photodissociation of Isoxazole and Pyridine Studied Using Chirped Pulse Microwave Spectroscopy in Pulsed Uniform Supersonic Flows

    Ariyasingha, Nuwandi M.; Joalland, Baptiste; Mebel, Alexander M.; Suits, Arthur

    2016-06-01

    Chirped - Pulse Fourier-transform microwave spectroscopy in uniform supersonic flows (Chirped- Pulse/Uniform Flow: CPUF) has been applied to study the photodissociation of two atmospherically relevant N containing heterocyclic compounds; pyridine and isoxazole. Products were detected using rotational spectroscopy. HC3N, HCN were observed for pyridine and CH3CN, HCO and HCN were observed for isoxazole and we report the first detection of HNC for both of the systems. Key points in potential energy surface were explored and compared with the experimental observations. Branching ratios were calculated for all the possible channels and will be presented.

  19. Desynchronization boost by non-uniform coordinated reset stimulation in ensembles of pulse-coupled neurons

    Leonhard eLücken

    2013-05-01

    Full Text Available Several brain diseases are characterized by abnormalneuronal synchronization. Desynchronization of abnormal neural synchronyis theoretically compelling because of the complex dynamical mechanismsinvolved. We here present a novel type of coordinated reset (CR stimulation.CR means to deliver phase resetting stimuli at different neuronalsub-populations sequentially, i.e. at times equidistantly distributedin a stimulation cycle. This uniform timing pattern seems to be intuitiveand actually applies to the neural network models used for the studyof CR so far. CR resets the population to an unstable cluster statefrom where it passes through a desynchronized transient, eventuallyresynchronizing if left unperturbed. In contrast, we show that theoptimal stimulation times are nonuniform. Using the model of weaklypulse-coupled neurons with phase response curves, we provide an approachthat enables to determine optimal stimulation timing patterns thatsubstantially maximize the desynchronized transient time followingthe application of CR stimulation. This approach includes an optimizationsearch for clusters in a low-dimensional pulse coupled map. As a consequence,model-specific non-uniformly spaced cluster states cause considerablylonger desynchronization transients. Intriguingly, such a desynchronizationboost with non-uniform CR stimulation can already be achieved by onlyslight modifications of the uniform CR timing pattern. Our resultssuggest that the non-uniformness of the stimulation times can be amedically valuable parameter in the calibration procedure for CR stimulation,where the latter has successfully been used in clinical and pre-clinicalstudies for the treatment of Parkinson's disease and tinnitus.

  20. Uniformity pattern and related criteria for two-level factorials

    FANG; Kaitai; QIN; Hong

    2005-01-01

    In this paper,the study of projection properties of two-level factorials in view of geometry is reported.The concept of uniformity pattern is defined.Based on this new concept,criteria of uniformity resolution and minimum projection uniformity are proposed for comparing two-level factorials.Relationship between minimum projection uniformity and other criteria such as minimum aberration,generalized minimum aberration and orthogonality is made explict.This close relationship raises the hope of improving the connection between uniform design theory and factorial design theory.Our results provide a justification of orthogonality,minimum aberration,and generalized minimum aberration from a natural geometrical interpretation.

  1. Inkjet printing for direct micropatterning of a superhydrophobic surface: Toward biomimetic fog harvesting surfaces

    Zhang, Lianbin

    2015-01-01

    The preparation of biomimetic superhydrophobic surfaces with hydrophilic micro-sized patterns is highly desirable, but a one-step, mask-free method to produce such surfaces has not previously been reported. We have developed a direct method to produce superhydrophilic micropatterns on superhydrophobic surfaces based on inkjet printing technology. This work was inspired by the efficient fog-harvesting behavior of Stenocara beetles in the Namib Desert. A mussel-inspired ink consisting of an optimized solution of dopamine was applied directly by inkjet printing to superhydrophobic surfaces. Stable Wenzel\\'s microdroplets of the dopamine solution with well-defined micropatterns were obtained on these surfaces. Superhydrophilic micropatterns with well-controlled dimensions were then readily achieved on the superhydrophobic surfaces by the formation of polydopamine via in situ polymerization. The micropatterned superhydrophobic surfaces prepared by this inkjet printing method showed enhanced water collection efficiency compared with uniform superhydrophilic and superhydrophobic surfaces. This method can be used for the facile large-scale patterning of superhydrophobic surfaces with high precision and superior pattern stability and is therefore a key step toward patterning superhydrophobic surfaces for practical applications. This journal is

  2. School Discipline, School Uniforms and Academic Performance

    Baumann, Chris; Krskova, Hana

    2016-01-01

    Purpose: The purpose of this paper is to examine the role of school discipline in achieving academic performance. The study aims to clarify the role of permissive "vis-à-vis" authoritative teaching styles with an overarching hypothesis that better discipline leads to better academic performance. The authors also probe whether uniformed…

  3. Uniform distribution of TiCp in TiCp/Zn-Al composites prepared by XDTM

    王香; 马旭梁; 李庆芬; 曾松岩

    2002-01-01

    The prefabricated Al/TiC alloy with high TiC particle content was prepared by XDTM process. The uniform distribution process of TiC particles in the stationary zinc melt was studied and analyzed using self-made experimental equipment, and the model of the uniform distribution process was built. The results show that zinc diffuses into the prepared Al/TiC alloy after it is placed in the zinc melt at temperatures below the melting point of aluminum, which leads to the decrease of the liquidus temperature of Al-Zn alloy in the surface layer of Al/TiC alloy. When the liquidus temperature of Al-Zn alloy is equal to or below the temperature of zinc melt, Al-Zn alloy melts and TiC particles drop with it from the Al/TiC alloy and then transfer into the zinc melt and finally distribute uniformly in it.

  4. Achieving form in autobiography

    Nicholas (Nick Meihuizen

    2014-06-01

    Full Text Available This article argues that, unlike biographies which tend to follow patterns based on conventional expectations, salient autobiographies achieve forms unique to themselves. The article draws on ideas from contemporary formalists such as Peter McDonald and Angela Leighton but also considers ideas on significant form stemming from earlier writers and critics such as P.N. Furbank and Willa Cather. In extracting from these writers the elements of what they consider comprise achieved form, the article does not seek to provide a rigid means of objectively testing the formal attributes of a piece of writing. It rather offers qualitative reminders of the need to be alert to the importance of form, even if the precise nature of this importance is not possible to define. Form is involved in meaning, and this continuously opens up possibilities regarding the reader’s relationship with the work in question. French genetic critic Debray Genette distinguishes between ‘semantic effect’ (the direct telling involved in writing and ‘semiological effect’ (the indirect signification involved. It is the latter, the article argues in summation, which gives a work its singular nature, producing a form that is not predictable but suggestive, imaginative.

  5. Uniform and Non-Uniform Single Image Deblurring Based on Sparse Representation and Adaptive Dictionary Learning

    Ashwini M. Deshpande

    2014-02-01

    Full Text Available Considering the sparseness property of images, a sparse representation based iterative deblurring method is presented for single image deblurring under uniform and non-uniform motion blur. The approach taken is based on sparse and redundant representations over adaptively training dictionaries from single blurred-noisy image itself. Further, the K-SVD algorithm is used to obtain a dictionary that describes the image contents effectively. Comprehensive experimental evaluation demonstrate that the proposed framework integrating the sparseness property of images, adaptive dictionary training and iterative deblurring scheme together significantly improves the deblurring performance and is comparable with the state-of-the art deblurring algorithms and seeks a powerful solution to an ill-conditioned inverse problem.

  6. Microbridge structures for uniform interval control of flowing droplets in microfluidic networks

    Lee, Do-Hyun; Lee, Wonhye; Um, Eujin; Park, Je-Kyun

    2011-01-01

    Precise temporal control of microfluidic droplets such as synchronization and combinatorial pairing of droplets is required to achieve a variety range of chemical and biochemical reactions inside microfluidic networks. Here, we present a facile and robust microfluidic platform enabling uniform interval control of flowing droplets for the precise temporal synchronization and pairing of picoliter droplets with a reagent. By incorporating microbridge structures interconnecting the droplet-carryi...

  7. Uniform Convergence Analysis for Singularly Perturbed Elliptic Problems with Parabolic Layers

    Jichun Li; Yitung Chen

    2008-01-01

    In this paper, using Lin's integral identity technique, we prove the optimal uniform convergence O(Nx-2 ln2Nx+ Ny-2 In2Ny) in the L2-norm for singularly per-turbed problems with parabolic layers. The error estimate is achieved by bilinear fi-nite elements on a Shishkin type mesh. Here Nx and Ny are the number of elements in the x- and y-directions, respectively. Numerical results are provided supporting our theoretical analysis.

  8. Uniform Page Migration Problem in Euclidean Space

    Amanj Khorramian

    2016-08-01

    Full Text Available The page migration problem in Euclidean space is revisited. In this problem, online requests occur at any location to access a single page located at a server. Every request must be served, and the server has the choice to migrate from its current location to a new location in space. Each service costs the Euclidean distance between the server and request. A migration costs the distance between the former and the new server location, multiplied by the page size. We study the problem in the uniform model, in which the page has size D = 1 . All request locations are not known in advance; however, they are sequentially presented in an online fashion. We design a 2.75 -competitive online algorithm that improves the current best upper bound for the problem with the unit page size. We also provide a lower bound of 2.732 for our algorithm. It was already known that 2.5 is a lower bound for this problem.

  9. On general relativistic uniformly rotating white dwarfs

    Boshkayev, Kuantay; Ruffini, Remo; Siutsou, Ivan

    2012-01-01

    Uniformly rotating white dwarfs (RWDs) are analyzed within the framework of general relativity. The Hartle's formalism is applied to construct self-consistently the internal and external solutions to the Einstein equations. The relativistic Feynman-Metropolis-Teller EoS that generalizes the Salpeter's one taking fully into account the finite size of nuclei, the Coulomb interactions as well as electroweak equilibrium in a self-consistent relativistic fashion is used to describe the WD matter. The mass, radius, angular momentum, eccentricity and quadrupole moment of RWDs are calculated as a function of the central density and rotation angular velocity. We construct the region of stability of RWDs taking into account the mass-shedding limit, inverse beta-decay instability, and the boundary established by the turning points of constant angular momentum sequences that separates stable from secularly unstable configurations. We found the minimum rotation periods 0.3, 0.5, 0.7 and 2.2 seconds and maximum masses 1.50...

  10. Uniform temperature profile for a dense array CPV receiver under non uniform illumination profile

    Riera, Sara; Barrau, Jérôme; Perona, Arnaud; Dollet, Alain; Rosell, Joan I.; Fréchette, Luc

    2014-09-01

    Previous experimental and numerical studies of hybrid cooling devices for CPV receivers were developed under uniform illumination profile conditions; but literature review shows that this uniformity assumption is difficult to satisfy in real conditions. This investigation presents the design and the validation of a hybrid cooling device able to tailor its local heat extraction capacity to 2D illumination profiles in order to provide a uniform temperature profile of the PV receiver as well as a low global thermal resistance coefficient. The inputs of the design procedure are the solar concentration, the coolant flow rate and its inlet temperature. As the illumination profile is 2D dependent, a matrix of pin fins is implemented and a hybrid Jet Impingement /Matrix of Pin Fins cooling device is experimentally tested and compared to a hybrid Jet Impingement / Microchannels cooling device developed previously. The results demonstrate similar performances for both designs. Furthermore, in contrast to the cooling scheme using longitudinal fins, the distribution of the pin fins can be tailored, in two dimensions, to the local need of heat extraction capacity.

  11. Measurement of Magnetic Field Uniformity For a Neutron Electric Dipole Moment Detector with New Lead Endcaps

    Kulkarni, Anita; Filippone, Bradley; Slutsky, Simon; Swank, Christopher; Carr, Robert; Osthelder, Charles; Biswas, Aritra; Molina, Daniel

    2016-09-01

    Over the last several decades, physicists have been measuring the neutron electric dipole moment (nEDM) with greater and greater sensitivity. The latest experiment we are developing will have 100 times more sensitivity than the previous leading experiment. A nonzero nEDM could, among other consequences, explain the presence of more matter than antimatter in the universe. To measure the nEDM with high accuracy, it is necessary to have a very uniform magnetic field inside the detector since non-uniformities can create false signals via the geometric phase effect. One way to improve field uniformity is to add superconducting lead endcaps to the detector, which constrain the fields at their surfaces to be parallel to them. Here, we test how the endcaps improve field uniformity by measuring the magnetic field at various points in a 1/3-scale experimental volume, inferring what the field must be at all other points, and calculating gradients in the field. This knowledge could help guide further steps needed to improve field uniformity and characterize limitations to the sensitivity of nEDM measurements for the full-scale experiment. Rose Hills Foundation, National Science Foundation Grant 1506459, and Department of Energy.

  12. Achieving diagnosis by consensus

    Kane, Bridget

    2009-08-01

    This paper provides an analysis of the collaborative work conducted at a multidisciplinary medical team meeting, where a patient’s definitive diagnosis is agreed, by consensus. The features that distinguish this process of diagnostic work by consensus are examined in depth. The current use of technology to support this collaborative activity is described, and experienced deficiencies are identified. Emphasis is placed on the visual and perceptual difficulty for individual specialities in making interpretations, and on how, through collaboration in discussion, definitive diagnosis is actually achieved. The challenge for providing adequate support for the multidisciplinary team at their meeting is outlined, given the multifaceted nature of the setting, i.e. patient management, educational, organizational and social functions, that need to be satisfied.

  13. Recognizing outstanding achievements

    Speiss, Fred

    One function of any professional society is to provide an objective, informed means for recognizing outstanding achievements in its field. In AGU's Ocean Sciences section we have a variety of means for carrying out this duty. They include recognition of outstanding student presentations at our meetings, dedication of special sessions, nomination of individuals to be fellows of the Union, invitations to present Sverdrup lectures, and recommendations for Macelwane Medals, the Ocean Sciences Award, and the Ewing Medal.Since the decision to bestow these awards requires initiative and judgement by members of our section in addition to a deserving individual, it seems appropriate to review the selection process for each and to urge you to identify those deserving of recognition.

  14. Achieving English Spoken Fluency

    王鲜杰

    2000-01-01

    Language is first and foremost oral,spoken language,speaking skill is the most important one of the four skills(L,S,R,W)and also it is the most difficult one of the four skills. To have an all-round command of a language one must be able to speak and to understand the spoken language, it is not enough for a language learner only to have a good reading and writing skills. As Englisn language teachers, we need to focus on improving learners' English speaking skill to meet the need of our society and our country and provide learner some useful techniques to achieving their English spoken fluency. This paper focuses on the spoken how to improving learners speaking skill.

  15. Achieving closure at Fernald

    Bradburne, John; Patton, Tisha C.

    2001-02-25

    When Fluor Fernald took over the management of the Fernald Environmental Management Project in 1992, the estimated closure date of the site was more than 25 years into the future. Fluor Fernald, in conjunction with DOE-Fernald, introduced the Accelerated Cleanup Plan, which was designed to substantially shorten that schedule and save taxpayers more than $3 billion. The management of Fluor Fernald believes there are three fundamental concerns that must be addressed by any contractor hoping to achieve closure of a site within the DOE complex. They are relationship management, resource management and contract management. Relationship management refers to the interaction between the site and local residents, regulators, union leadership, the workforce at large, the media, and any other interested stakeholder groups. Resource management is of course related to the effective administration of the site knowledge base and the skills of the workforce, the attraction and retention of qualified a nd competent technical personnel, and the best recognition and use of appropriate new technologies. Perhaps most importantly, resource management must also include a plan for survival in a flat-funding environment. Lastly, creative and disciplined contract management will be essential to effecting the closure of any DOE site. Fluor Fernald, together with DOE-Fernald, is breaking new ground in the closure arena, and ''business as usual'' has become a thing of the past. How Fluor Fernald has managed its work at the site over the last eight years, and how it will manage the new site closure contract in the future, will be an integral part of achieving successful closure at Fernald.

  16. Das materialidades da escola: o uniforme escolar On the materialities of school: the school uniform

    Ivanir Ribeiro

    2012-09-01

    Full Text Available Este texto dedica-se a situar o uniforme escolar como objeto histórico e como importante fonte do e no universo escolar. Para tanto, empreende-se uma revisão da literatura que aborda a temática e investe-se em uma reflexão que concebe esse artefato como uma das expressões da materialidade que dá contornos à forma escolar, tomando-o na perspectiva da cultura material. Alguns autores servem aqui de referência: Richard Bucaille, Jean-Marie Pesez e Ulpiano Bezerra de Meneses, nos estudos em que se dedicam à cultura material; Agustín Benito Escolano e Rosa Fátima de Souza, nos trabalhos em que voltam o olhar para cultura material escolar; Inês Dussel e Katiene Nogueira da Silva, autoras que abordam diretamente a questão dos uniformes escolares. Não menos importantes para efeitos deste artigo são os trabalhos que tratam do movimento higienista, particularmente aqueles levados a cabo por José Gondra. Os dados levantados e as reflexões efetuadas indiciam dois movimentos (ou tensões nada desprezíveis. Por um lado, são evidentes as dificuldades encontradas para adoção dos uniformes escolares por todos os alunos, tanto por parte do Estado quanto por parte das famílias, devido ao fato de eles representarem um custo elevado, principalmente os calçados, artigos pouco utilizados pela maioria da população até, no mínimo, meados do século XX. Por outro lado, há indícios de que esse traje desempenhava uma função niveladora importante. Por meio dele, criava-se uma ideia de padronização e democratização do ensino, mesmo que em aparência, além de se dar visibilidade pública a uma instituição social cada vez mais importante: a escola.This text is devoted to situate the school uniform as a historical object, and as an important source on and in the school universe. For that, a literature survey is carried out on this theme, and a reflection is conducted envisaging this artifact as one of the expressions of materiality that

  17. Multi Product Inventory Optimization using Uniform Crossover Genetic Algorithm

    Narmadha, S; Sathish, G

    2010-01-01

    Inventory management is considered to be an important field in Supply Chain Management because the cost of inventories in a supply chain accounts for about 30 percent of the value of the product. The service provided to the customer eventually gets enhanced once the efficient and effective management of inventory is carried out all through the supply chain. The precise estimation of optimal inventory is essential since shortage of inventory yields to lost sales, while excess of inventory may result in pointless storage costs. Thus the determination of the inventory to be held at various levels in a supply chain becomes inevitable so as to ensure minimal cost for the supply chain. The minimization of the total supply chain cost can only be achieved when optimization of the base stock level is carried out at each member of the supply chain. This paper deals with the problem of determination of base stock levels in a ten member serial supply chain with multiple products produced by factories using Uniform Crosso...

  18. Nanomagnetic logic with non-uniform states of clocking

    Puliafito, Vito; Giordano, Anna; Azzerboni, Bruno; Finocchio, Giovanni

    2016-04-01

    Nanomagnetic logic transmits information along a path of nanomagnets. The basic mechanism to drive such a transmission, known as clocking, can be achieved by exploiting the spin-Hall effect (SHE), as recently observed in experiments on Ta/CoFeB/MgO multilayers (Bhowmik et al 2014 Nat. Nano 9 59). This paper shows the fundamental mechanism of the spin-Hall driven clocking by using a full micromagnetic framework and considering two different devices, Ta/CoFeB/MgO and Pt/CoFeB/MgO. The former is used for a direct comparison of the numerical results with the experiments while the latter permits the effect of the Dzyaloshinskii-Moriya interaction (DMI) in the clocking mechanism to be predicted. Results show that the clocking state is non-uniform and it is characterized by the presence of domains separated by Bloch (Néel) domain walls depending on the absence (presence) of the DMI. Our findings point out that for the design of nanomagnetic logic a full micromagnetic approach is necessary.

  19. Spherical Accretion in a Uniformly Expanding Universe

    Colpi, Monica; Shapiro, Stuart L.; Wasserman, Ira

    1996-10-01

    We consider spherically symmetric accretion of material from an initially homogeneous, uniformly expanding medium onto a Newtonian point mass M. The gas is assumed to evolve adiabatically with a constant adiabatic index F, which we vary over the range Γ ɛ [1, 5/3]. We use a one-dimensional Lagrangian code to follow the spherical infall of material as a function of time. Outflowing shells gravitationally bound to the point mass fall back, giving rise to a inflow rate that, after a rapid rise, declines as a power law in time. If there were no outflow initially, Bondi accretion would result, with a characteristic accretion time-scale ta,0. For gas initially expanding at a uniform rate, with a radial velocity U = R/t0 at radius R, the behavior of the flow at all subsequent times is determined by ta,0/t0. If ta,0/t0 ≫ 1, the gas has no time to respond to pressure forces, so the fluid motion is nearly collisionless. In this case, only loosely bound shells are influenced by pressure gradients and are pushed outward. The late-time evolution of the mass accretion rate Mdot is close to the result for pure dust, and we develop a semianalytic model that accurately accounts for the small effect of pressure gradients in this limit. In the opposite regime, ta,0/t0 ≪ 1, pressure forces significantly affect the motion of the gas. At sufficiently early times, t ≤ ttr, the flow evolved along a sequence of quasi-stationary, Bondi-like states, with a time-dependent Mdot determined by the slowly varying gas density at large distances. However, at later times, t ≥ ttr, the fluid flow enters a dustllke regime; ttr is the time when the instantaneous Bondi accretion radius reaches the marginally bound radius. The transition time ttr depends sensitively on ta,0/t0 for a given Γ and can greatly exceed t0. We show that there exists a critical value Γ = 11/9, below which the transition from fluid to ballistic motion disappears. As one application of our calculations, we consider the

  20. Principle of uniformity of temperature difference field in heat exchanger

    过增元; 李志信; 周森泉; 熊大曦

    1996-01-01

    A principle of uniformity of temperature difference field (TDF) in heat exchangers is advanced.It states that the more uniform the temperature difference field,the higher the effectiveness of heat exchanger for a given NTU and C,.Analytical and numerical results on the uniformity of TDF and effectiveness of thirteen types of heat exchangers show the validity of the uniformity principle.Its further verification is given by the asymptotical solution of TDF in terms of a recurrence formula of heat transfer area distribution.The analyses of entropy generation caused by heat transfer indicate that the uniformity principle is based on the second law of thermodynamics.Two ways,redistributing heat transfer areas and varying the connection between tubes,are presented for the improvement of the uniformity of TDF and the consequent increase of effectiveness for crossflow heat exchangers.

  1. CONSTRUCTING UNIFORM DESIGNS WITH TWO- OR THREE-LEVEL

    2006-01-01

    When the number of runs is large, to search for uniform designs in the sense of low-discrepancy is an NP hard problem. The number of runs of most of the available uniform designs is small (≤ 50). In this article, the authors employ a kind of the so-called Hamming distance method to construct uniform designs with two- or three-level such that some resulting uniform designs have a large number of runs. Several infinite classes for the existence of uniform designs with the same Hamming distances between any distinct rows are also obtained simultaneously. Two measures of uniformity, the centered L2-discrepancy (CD, for short) and wrap-around L2-discrepancy (WD, for short), are employed.

  2. Motion Planning of Redundant Manipulators for Painting Uniform Thick Coating in Irregular Duct

    Yan Chen

    2016-01-01

    Full Text Available The paper presents a motion planning method of redundant manipulator for painting uniform thick coating on the interior of irregular duct of some aircrafts. Discontinuous peripheral painting method is employed by analyzing the restrictions during painting the duct. For improving the longitudinal uniformity of thick coating, the interlacing painting method plans two sets of sweeping paths and an interlacing distance between the starting paths of the two times of painting. The interlacing distance and overlapping distance are optimized by establishing and analyzing the model of longitudinal uniformity. To enhance the transverse uniformity, sweeping speeds for curved surfaces are calculated by the ratio of transfer efficiency after the basic sweeping speed for the plane is determined. The intertwining method, minimizing the sum of the weighed distances between the duct centerline and key points of the manipulator links, is employed for the joint trajectory planning without collision. The simulation and experiment results show that the redundant manipulators can finish painting the internal surface of the irregular S-shaped duct without collision. The maximum relative deviation is 16.3% and the thicknesses of all measurement points satisfy the acceptance criteria of the factory.

  3. Uniform Atomic Layer Deposition of Al2O3 on Graphene by Reversible Hydrogen Plasma Functionalization

    2017-01-01

    A novel method to form ultrathin, uniform Al2O3 layers on graphene using reversible hydrogen plasma functionalization followed by atomic layer deposition (ALD) is presented. ALD on pristine graphene is known to be a challenge due to the absence of dangling bonds, leading to nonuniform film coverage. We show that hydrogen plasma functionalization of graphene leads to uniform ALD of closed Al2O3 films down to 8 nm in thickness. Hall measurements and Raman spectroscopy reveal that the hydrogen plasma functionalization is reversible upon Al2O3 ALD and subsequent annealing at 400 °C and in this way does not deteriorate the graphene’s charge carrier mobility. This is in contrast with oxygen plasma functionalization, which can lead to a uniform 5 nm thick closed film, but which is not reversible and leads to a reduction of the charge carrier mobility. Density functional theory (DFT) calculations attribute the uniform growth on both H2 and O2 plasma functionalized graphene to the enhanced adsorption of trimethylaluminum (TMA) on these surfaces. A DFT analysis of the possible reaction pathways for TMA precursor adsorption on hydrogenated graphene predicts a binding mechanism that cleans off the hydrogen functionalities from the surface, which explains the observed reversibility of the hydrogen plasma functionalization upon Al2O3 ALD.

  4. Evaluation of illumination system uniformity for wide-field biomedical hyperspectral imaging

    Sawyer, Travis W.; Siri Luthman, A.; Bohndiek, Sarah E.

    2017-04-01

    Hyperspectral imaging (HSI) systems collect both spatial (morphological) and spectral (chemical) information from a sample. HSI can provide sensitive analysis for biological and medical applications, for example, simultaneously measuring reflectance and fluorescence properties of a tissue, which together with structural information could improve early cancer detection and tumour characterisation. Illumination uniformity is a critical pre-condition for quantitative data extraction from an HSI system. Non-uniformity can cause glare, specular reflection and unwanted shading, which negatively impact statistical analysis procedures used to extract abundance of different chemical species. Here, we model and evaluate several illumination systems frequently used in wide-field biomedical imaging to test their potential for HSI. We use the software LightTools and FRED. The analysed systems include: a fibre ring light; a light emitting diode (LED) ring; and a diffuse scattering dome. Each system is characterised for spectral, spatial, and angular uniformity, as well as transfer efficiency. Furthermore, an approach to measure uniformity using the Kullback–Leibler divergence (KLD) is introduced. The KLD is generalisable to arbitrary illumination shapes, making it an attractive approach for characterising illumination distributions. Although the systems are quite comparable in their spatial and spectral uniformity, the most uniform angular distribution is achieved using a diffuse scattering dome, yielding a contrast of 0.503 and average deviation of 0.303 over a ±60° field of view with a 3.9% model error in the angular domain. Our results suggest that conventional illumination sources can be applied in HSI, but in the case of low light levels, bespoke illumination sources may offer improved performance.

  5. The Influence of Non-Uniform High Heat Flux on Thermal Stress of Thermoelectric Power Generator

    Tingzhen Ming

    2015-11-01

    Full Text Available A thermoelectric generator (TEG device which uses solar energy as heat source would achieve higher efficiency if there is a higher temperature difference between the hot-cold ends. However, higher temperature or higher heat flux being imposed upon the hot end will cause strong thermal stress, which will have a negative influence on the life cycle of the thermoelectric module. Meanwhile, in order to get high heat flux, a Fresnel lens is required to concentrate solar energy, which will cause non-uniformity of heat flux on the hot end of the TEG and further influence the thermal stress of the device. This phenomenon is very common in solar TEG devices but seldom research work has been reported. In this paper, numerical analysis on the heat transfer and thermal stress performance of a TEG module has been performed considering the variation on the power of the heat flux being imposed upon the hot-end; the influence of non-uniform high heat flux on thermal stress has also been analyzed. It is found that non-uniformity of high heat flux being imposed upon the hot end has a significant effect on the thermal stress of TEG and life expectation of the device. Taking the uniformity of 100% as standard, when the heating uniformity is 70%, 50%, 30%, and 10%, respectively, the maximum thermal stress of TEG module increased by 3%, 6%, 12%, and 22% respectively. If we increase the heat flux on the hot end, the influence of non-uniformity on the thermal stress will be more remarkable.

  6. Achievement Goals and Achievement Emotions: A Meta-Analysis

    Huang, Chiungjung

    2011-01-01

    This meta-analysis synthesized 93 independent samples (N = 30,003) in 77 studies that reported in 78 articles examining correlations between achievement goals and achievement emotions. Achievement goals were meaningfully associated with different achievement emotions. The correlations of mastery and mastery approach goals with positive achievement…

  7. The structure of uniform B-spline curves with parameters

    Juan Cao; Guozhao Wang

    2008-01-01

    The shape-adjustable curve constructed by uniform B-spline basis function with parameter is an extension of uniform B-spline curve. In this paper, we study the relation between the uniform B-spline basis functions with parameter and the B-spline basis functions. Based on the degree elevation of B-spline, we extend the uniform B-spline basis functions with parameter to ones with multiple parameters. Examples show that the proposed basis functions provide more flexibility for curve design.

  8. 14 CFR Section 19 - Uniform Classification of Operating Statistics

    2010-01-01

    ... Statistics Section 19 Section 19 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION... AIR CARRIERS Operating Statistics Classifications Section 19 Uniform Classification of Operating Statistics...

  9. Droplet condensation on chemically homogeneous and heterogeneous surfaces

    Ashrafi, Amir; Moosavi, Ali

    2016-09-01

    Nucleation and growth of condensing droplets on horizontal surfaces are investigated via a 2-D double distribution function thermal lattice Boltzmann method. First, condensation on completely uniform surface is investigated and different mechanisms which cause dropwise and filmwise condensation are studied. The results reveal the presence of cooled vapor layer instability in the condensation on completely smooth surfaces. In the second step, condensation on chemically heterogeneous surfaces is investigated. Moreover, the effect of non-uniformity in the surface temperature is also studied. The results indicate that the vapor layer instability and the nucleation start from the heterogeneities. The effects of different numbers of heterogeneities, their distance, and hydrophobicity on the condensation are also inspected. It is shown that by increasing the hydrophobicity of the heterogeneities and considering an optimum space between the heterogeneities, maximum condensation performance can be achieved. Finally, condensation on wettability gradient surfaces is studied and the effects of the gradient form and contact angle of the core region on the condensation are studied. It is shown that hydrophobicity of the core region plays a key role in increasing the condensation performance. A heat transfer analysis and flow dynamics of dropwise condensation as a function of time is also presented and it is shown that the results are in good agreements with the previous theoretical and experimental results.

  10. Vietnam: achievements and challenges.

    Tran Tien Duc

    1999-01-01

    The Vietnamese Government's successful development of the National Population and Family Planning Program has contributed in raising people's awareness on population issues and changing their attitudes and behavior regarding fostering small families. It has also been found to be very effective in substantially decreasing fertility level. In addition, economic levels of many households have been greatly improved since the adoption of a renovation policy. The advancement of welfare accompanied by the provision of better basic social services, including health services, has boost people's health. Several factors behind the achievements of the National Population and Family Planning Program include: 1) Strengthening of the political commitment of national and local leaders; 2) Nationwide mobilization of mass organizations and NGOs; 3) A strong advocacy and information, education and communication program; 4) Provision of various kinds of contraceptives; 5) Effective management of the program by priority; and 6) Support of the international community. Despite such successes, Vietnam is facing a number of new issues such as enlargement of the work force, shifting migration patterns and accelerating urbanization, aging of population, and change of household structure. Nevertheless, the Government of Vietnam is preparing a New Population Strategy aimed to address these issues.

  11. Signal Detection for Uniform Renewal Processes.

    1982-06-01

    a surface) are N N 2 A N N 2-N X ajqj ,f= aj; T N ! b~.Ij bN I a J q1 j bjqj 1 b Jul Jul jul ’ jl For N > 2, after some algebraic simplification the... Durbin , J. (1961). Sow methods of constructing exact tests, Biometrika, 48, 41-55. S. Durbin , J. (1973). Distribution Iheo for Tests &smd a the Sample

  12. Design of a highly stable and uniform thermal test facility for MGRS development

    Higuchi, Sei; Sun, Ke-Xun; DeBra, Daniel B.; Buchman, Saps; Byer, Robert L.

    2009-03-01

    We have designed combined passive and active thermal control system to achieve sub microkelvin temperature stability and uniformity over an optics bench size enclosure, which has an analogous structure to the LISA spacecraft. For the passive control, we have constructed a new thermal enclosure that has a multilayer structure with alternative conducting and insulating layers, which enables the temperature uniformity and ease the burden of the active control. The thermal enclosure becomes an important test facility for Modular Gravitational Reference Sensor (MGRS) development. For the active control, we have developed a model predictive control (MPC) algorithm, which will regulate temperature variations of the proof-mass (PM) down to sub-microkelvin over the LISA science band. The LISA mission requires extremely tight temperature control, which is as low as 30 μK/ over 0.1 mHz to 1 Hz. Both temporal stability and spatial uniformity in temperature must be achieved. Optical path length variations on optical bench must be kept below 40 pm/ over 0.1 mHz to 1 Hz. Temperature gradient across the proof mass housing also must be controlled to reduce differential thermal pressure. Thermal disturbances due to, for example, solar radiation and heat generation from electronics, are expected to be significant disturbance source to the LISA sensitivity requirements. The MGRS will alleviate the thermal requirement due to its wider gap between the proof-mass and the housing wall. However, a thermally stable and uniform environment is highly desirable to achieve more precise science measurement for future space science missions.

  13. Design of a highly stable and uniform thermal test facility for MGRS development

    Higuchi, Sei; Sun Kexun; DeBra, Daniel B; Buchman, Saps; Byer, Robert L, E-mail: seihiguchi@stanford.ed [Hansen Experimental Physics Laboratory, Stanford University, 452 Lomita Mall, Stanford, CA 94305 (United States)

    2009-03-01

    We have designed combined passive and active thermal control system to achieve sub microkelvin temperature stability and uniformity over an optics bench size enclosure, which has an analogous structure to the LISA spacecraft. For the passive control, we have constructed a new thermal enclosure that has a multilayer structure with alternative conducting and insulating layers, which enables the temperature uniformity and ease the burden of the active control. The thermal enclosure becomes an important test facility for Modular Gravitational Reference Sensor (MGRS) development. For the active control, we have developed a model predictive control (MPC) algorithm, which will regulate temperature variations of the proof-mass (PM) down to sub-microkelvin over the LISA science band. The LISA mission requires extremely tight temperature control, which is as low as 30 muK/sq rootHz over 0.1 mHz to 1 Hz. Both temporal stability and spatial uniformity in temperature must be achieved. Optical path length variations on optical bench must be kept below 40 pm/sq rootHz over 0.1 mHz to 1 Hz. Temperature gradient across the proof mass housing also must be controlled to reduce differential thermal pressure. Thermal disturbances due to, for example, solar radiation and heat generation from electronics, are expected to be significant disturbance source to the LISA sensitivity requirements. The MGRS will alleviate the thermal requirement due to its wider gap between the proof-mass and the housing wall. However, a thermally stable and uniform environment is highly desirable to achieve more precise science measurement for future space science missions.

  14. Numerical analysis on the deformation of free surface of magnetic fluid. 1st Report. In the case of steady non-uniform magnetic field; Jisei ryutai no jiyu kaimen no henkei ni kansuru suchi kaiseki. 1. Teijo hiichiyo jiba no baai

    Nam, W.; Watanabe, T. [Iwate University, Iwate (Japan)

    1996-01-25

    Numerical analysis is conducted on the deformation of the free surface of a magnetic fluid. Applied magnetic fields are steadily induced by a circular current loop located under the magnetic fluid. Governing equations of magnetic fields are solved using the concept of vector potential. Fluid flow is calculated by using the finite volume method with marker particles. The surface of the magnetic fluid is formed the balance of surface force, gravity, pressure difference, magnetic normal pressure and magnetic body force. The results of simulation show the instability of the free surface of the magnetic fluid due to the effect of the magnetic terms. The rise and fall pattern of the free surface of the magnetic fluid are qualitatively clarified, and the patterns of a steady nonuniform magnetic field induced by a circular current loop are quantitatively presented. 8 refs., 8 figs.

  15. Geometry Modeling of Ship Hull Based on Non-uniform B-spline

    WANG Hu; ZOU Zao-jian

    2008-01-01

    In order to generate the three-dimensional (3-D) hull surface accurately and smoothly, a mixed method which is made up of non-uniform B-spline together with an iterative procedure was developed. By using the iterative method the data points on each section curve are calculated and the generalized waterlines and transverse section curves are determined. Then using the non-uniform B-spline expression, the control vertex net of the hull is calculated based on the generalized waterlines and section curves. A ship with tunnel stern was taken as test case. The numerical results prove that the proposed approach for geometry modeling of 3-D ship hull surface is accurate and effective.

  16. Fabrication of uniformly cell-laden porous scaffolds using a gas-in-liquid templating technique.

    Takei, Takayuki; Aokawa, Ryuta; Shigemitsu, Takamasa; Kawakami, Koei; Yoshida, Masahiro

    2015-11-01

    Design of porous scaffolds in tissue engineering field was challenging. Uniform immobilization of cells in the scaffolds with high porosity was essential for homogeneous tissue formation. The present study was aimed at fabricating uniformly cell-laden porous scaffolds with porosity >74% using the gas-in-liquid foam templating technique. To this end, we used gelatin, microbial transglutaminase and argon gas as a scaffold material, cross-linker of the protein and porogen of scaffold, respectively. We confirmed that a porosity of >74% could be achieved by increasing the gas volume delivered to a gelatin solution. Pore size in the scaffold could be controlled by stirring speed, stirring time and the pore size of the filter through which the gas passed. The foaming technique enabled us to uniformly immobilize a human hepatoblastoma cell line in scaffold. Engraftment efficiency of the cell line entrapped within the scaffold in nude mice was higher than that of cells in free-form. These results showed that the uniformly cell-laden porous scaffolds were promising for tissue engineering.

  17. Uniform electric field generation in circular multi-well culture plates using polymeric inserts

    Tsai, Hsieh-Fu; Cheng, Ji-Yen; Chang, Hui-Fang; Yamamoto, Tadashi; Shen, Amy Q.

    2016-01-01

    Applying uniform electric field (EF) in vitro in the physiological range has been achieved in rectangular shaped microchannels. However, in a circular-shaped device, it is difficult to create uniform EF from two electric potentials due to different electrical resistances originated from the length difference between the diameter of the circle and the length of any parallel chord of the bottom circular chamber where cells are cultured. To address this challenge, we develop a three-dimensional (3D) computer-aided designed (CAD) polymeric insert to create uniform EF in circular shaped multi-well culture plates. A uniform EF with a coefficient of variation (CV) of 1.2% in the 6-well plate can be generated with an effective stimulation area percentage of 69.5%. In particular, NIH/3T3 mouse embryonic fibroblast cells are used to validate the performance of the 3D designed Poly(methyl methacrylate) (PMMA) inserts in a circular-shaped 6-well plate. The CAD based inserts can be easily scaled up (i.e., 100 mm dishes) to further increase effective stimulation area percentages, and also be implemented in commercially available cultureware for a wide variety of EF-related research such as EF-cell interaction and tissue regeneration studies. PMID:27193911

  18. A large volume uniform plasma generator for the experiments of electromagnetic wave propagation in plasma

    Yang Min; Li Xiaoping; Xie Kai; Liu Donglin [School of Electronical and Mechanical Engineering, Xidian University, Xi' an Shaanxi 710071 (China); Liu Yanming [School of Telecommunications Engineering, Xidian University, Xi' an Shaanxi 710071 (China)

    2013-01-15

    A large volume uniform plasma generator is proposed for the experiments of electromagnetic (EM) wave propagation in plasma, to reproduce a 'black out' phenomenon with long duration in an environment of the ordinary laboratory. The plasma generator achieves a controllable approximate uniform plasma in volume of 260 mm Multiplication-Sign 260 mm Multiplication-Sign 180 mm without the magnetic confinement. The plasma is produced by the glow discharge, and the special discharge structure is built to bring a steady approximate uniform plasma environment in the electromagnetic wave propagation path without any other barriers. In addition, the electron density and luminosity distributions of plasma under different discharge conditions were diagnosed and experimentally investigated. Both the electron density and the plasma uniformity are directly proportional to the input power and in roughly reverse proportion to the gas pressure in the chamber. Furthermore, the experiments of electromagnetic wave propagation in plasma are conducted in this plasma generator. Blackout phenomena at GPS signal are observed under this system and the measured attenuation curve is of reasonable agreement with the theoretical one, which suggests the effectiveness of the proposed method.

  19. Uniform electric field generation in circular multi-well culture plates using polymeric inserts

    Tsai, Hsieh-Fu; Cheng, Ji-Yen; Chang, Hui-Fang; Yamamoto, Tadashi; Shen, Amy Q.

    2016-05-01

    Applying uniform electric field (EF) in vitro in the physiological range has been achieved in rectangular shaped microchannels. However, in a circular-shaped device, it is difficult to create uniform EF from two electric potentials due to different electrical resistances originated from the length difference between the diameter of the circle and the length of any parallel chord of the bottom circular chamber where cells are cultured. To address this challenge, we develop a three-dimensional (3D) computer-aided designed (CAD) polymeric insert to create uniform EF in circular shaped multi-well culture plates. A uniform EF with a coefficient of variation (CV) of 1.2% in the 6-well plate can be generated with an effective stimulation area percentage of 69.5%. In particular, NIH/3T3 mouse embryonic fibroblast cells are used to validate the performance of the 3D designed Poly(methyl methacrylate) (PMMA) inserts in a circular-shaped 6-well plate. The CAD based inserts can be easily scaled up (i.e., 100 mm dishes) to further increase effective stimulation area percentages, and also be implemented in commercially available cultureware for a wide variety of EF-related research such as EF-cell interaction and tissue regeneration studies.

  20. Uniform Magnetic Field Between Face-to-Face HTS Bulk Magnets Combining Concave and Convex Magnetic Field Distributions

    Oka, T.; Takahashi, Y.; Yaginuma, S.; Ogawa, J.; Fukui, S.; Sato, T.; Yokoyama, K.; Nakamura, T.

    The authors have been attempting to obtain the uniform magnetic field distribution in the space between the face-to-face HTS bulk magnets. The magnetic poles containing the HTS bulk magnets are usually characterized as non-uniform magnetic field distribution. Since the distributions show the conical or convex shapes, it is difficult to obtain the uniform magnetic field spaces even when the magnetic poles would be placed face-to-face. The authors have modified the shape of the distribution of one-side magnetic pole by attaching an iron plate on the surface, and formed the concave magnetic field distribution on the pole surface. The steep concave or convex distributions at each pole surface change to be flat with increasing distance from the pole surface. After the experimental result recording the best uniformity of 358 ppm by combining the concave and convex field distributions face-to-face, we attempted to simulate the feasible performance in this configuration. In the numerical simulation, the concave field distribution modified by attaching an imaginary spiral coil on the pole surface was coupled with the original convex field. We succeeded in obtaining the best uniformity of 30 ppm at 1.1 T in 4 x 4 mm2x-y plane at 7 mm distant from the pole surface in the gap of 30 mm. This result suggests that the concave and convex magnetic field distributions compensate the field uniformity with each other with keeping the magnetic field strength in the gap, and also suggests the novel compact NMR/MRI devices in the future.

  1. Optimising Blackbody Cavity Shape for Spatially Uniform Integrated Emissivity

    Saunders, P.

    2017-01-01

    The emissivity of a blackbody cavity, as seen by a radiation thermometer viewing the cavity, depends on both the field of view of the thermometer and the distribution of local effective emissivity values within the field of view. For cylindro-conical cavities, the local effective emissivity generally attains a maximum value at the apex of the cone and drops along the conical section. Thus, radiation thermometers with different fields of view see different blackbody emissivity values. This impacts, particularly, on the calibration of wide-angle low-temperature radiation thermometers and thermal imaging systems where each pixel responds to a different radiance. The spatial uniformity of the effective emissivity profile depends principally on the cone angle, with a weaker dependence on the length-to-diameter ratio of the cavity, the intrinsic emissivity of the cavity surfaces, and the temperature gradient along the cavity. In this paper, a nonlinear least-squares method is used to determine the optimal cone angle as a function of the cavity parameters. It is concluded that full cone angles close to 160° provide the flattest effective emissivity profile across the conical section of the cavity for typical cavity parameters. A method is also described for calculating the value of integrated emissivity, which includes the umbral and penumbral regions seen by an imaging radiation thermometer.

  2. Trivelpiece-Gould modes in a uniform unbounded plasma

    Stenzel, R. L.; Urrutia, J. M.

    2016-09-01

    Trivelpiece-Gould (TG) modes originally described electrostatic surface waves on an axially magnetized cylindrical plasma column. Subsequent studies of electromagnetic waves in such plasma columns revealed two modes, a predominantly magnetic helicon mode (H) and the mixed magnetic and electrostatic Trivelpiece-Gould modes (TG). The latter are similar to whistler modes near the oblique cyclotron resonance in unbounded plasmas. The wave propagation in cylindrical geometry is assumed to be paraxial while the modes exhibit radial standing waves. The present work shows that TG modes also arise in a uniform plasma without radial standing waves. It is shown experimentally that oblique cyclotron resonance arises in large mode number helicons. Their azimuthal wave number far exceeds the axial wave number which creates whistlers near the oblique cyclotron resonance. Cyclotron damping absorbs the TG mode and can energize electrons in the center of a plasma column rather than the edge of conventional TG modes. The angular orbital field momentum can produce new perpendicular wave-particle interactions.

  3. Spinning Janus doublets driven in uniform ac electric fields

    Boymelgreen, Alicia; Yossifon, Gilad; Park, Sinwook; Miloh, Touvia

    2014-01-01

    We provide an experimental proof of concept for a robust, continuously rotating microstructure—consisting of two metallodielectric (gold-polystyrene) Janus particles rigidly attached to each other—which is driven in uniform ac fields by asymmetric induced-charge electro-osmosis. The pairs (doublets) are stabilized on the substrate surface which is parallel to the plane of view and normal to the direction of the applied electric field. We find that the radius of orbit and angular velocity of the pair are predominantly dependent on the relative orientations of the interfaces between the metallic and dielectric hemispheres and that the electrohydrodynamic particle-particle interactions are small. Additionally, we verify that both the angular and linear velocities of the pair are proportional to the square of the applied field which is consistent with the theory for nonlinear electrokinetics. A simple kinematic rigid body model is used to predict the paths and doublet velocities (angular and linear) based on their relative orientations with good agreement.

  4. Surface modification of polymeric materials by cold atmospheric plasma jet

    Kostov, K.G., E-mail: kostov@feg.unesp.br [Faculty of Engineering in Guaratinguetá–FEG, Universidade Estadual Paulista–UNESP Guaratiguetá, 12516-410, SP (Brazil); Nishime, T.M.C.; Castro, A.H.R. [Faculty of Engineering in Guaratinguetá–FEG, Universidade Estadual Paulista–UNESP Guaratiguetá, 12516-410, SP (Brazil); Toth, A. [Institute of Material and Environmental Chemistry, Hungarian Academy of Science P.O. Box 17, H-1525, Budapest (Hungary); Hein, L.R.O. [Faculty of Engineering in Guaratinguetá–FEG, Universidade Estadual Paulista–UNESP Guaratiguetá, 12516-410, SP (Brazil)

    2014-09-30

    Highlights: • We investigate polymer surface modification by atmospheric pressure plasma jet APPJ. • Jet operation conditions for uniform surface modification were determined. • The APPJ added O atoms to the polymer surface and also enhanced the roughness. • The degree of polymer surface modification by APPJ and DBD were compared. • The APPJ is more efficient in attaching O atoms and produces less polymer fragments. - Abstract: In this work we report the surface modification of different engineering polymers, such as, polyethylene terephthalate (PET), polyethylene (PE) and polypropylene (PP) by an atmospheric pressure plasma jet (APPJ). It was operated with Ar gas using 10 kV, 37 kHz, sine wave as an excitation source. The aim of this study is to determine the optimal treatment conditions and also to compare the polymer surface modification induced by plasma jet with the one obtained by another atmospheric pressure plasma source – the dielectric barrier discharge (DBD). The samples were exposed to the plasma jet effluent using a scanning procedure, which allowed achieving a uniform surface modification. The wettability assessments of all polymers reveal that the treatment leads to reduction of more than 40° in the water contact angle (WCA). Changes in surface composition and chemical bonding were analyzed by x-ray photoelectron spectroscopy (XPS) and Fourier-Transformed Infrared spectroscopy (FTIR) that both detected incorporation of oxygen-related functional groups. Surface morphology of polymer samples was investigated by Atomic Force Microscopy (AFM) and an increase of polymer roughness after the APPJ treatment was found. The plasma-treated polymers exhibited hydrophobic recovery expressed in reduction of the O-content of the surface upon rinsing with water. This process was caused by the dissolution of low molecular weight oxidized materials (LMWOMs) formed on the surface as a result of the plasma exposure.

  5. The Key Factor for Uniform and Patterned Glow Dielectric Barrier Discharge

    OUYANG Ji-Ting; DUAN Xiao-Xi; XU Shao-Wei; HE Feng

    2012-01-01

    We present the results from 2D fluid modeling of the key roles controlling the glow dielectric barrier discharge (DBD) structure. A uniform DBD can be sustained at lower frequency when the space charge reaches uniformity due to plasma decay, while the patterned structure appears above a critical frequency when the space charge is nonuniform. The patterns start from the electrode edge where the electric field is significantly distorted, characterized by the patterned seed electrons that always form ahead of the surface charges. The formation of the patterned DBD structure is associated with the lateral inhibition of the local increase of space charges. The distribution of the volume seed electrons plays a key role in the DBD structure while the distribution of surface charge is a result of the formed structure.%We present the results from 2D fluid modeling of the key roles controlling the glow dielectric barrier discharge (DBD) structure.A uniform DBD can be sustained at lower frequency when the space charge reaches uniformity due to plasma decay,while the patterned structure appears above a critical frequency when the space charge is nonuniform.The patterns start from the electrode edge where the electric field is significantly distorted,characterized by the patterned seed electrons that always form ahead of the surface charges.The formation of the patterned DBD structure is associated with the lateral inhibition of the local increase of space charges.The distribution of the volume seed electrons plays a key role in the DBD structure while the distribution of surface charge is a result of the formed structure.

  6. 7 CFR 51.2085 - Fairly uniform color.

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Fairly uniform color. 51.2085 Section 51.2085 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... color. Fairly uniform color means that the shells do not show excessive variation in color,...

  7. 7 CFR 51.1447 - Fairly uniform in color.

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Fairly uniform in color. 51.1447 Section 51.1447... color. Fairly uniform in color means that 90 percent or more of the kernels in the lot have skin color within the range of one or two color classifications....

  8. 7 CFR 51.1407 - Fairly uniform in color.

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Fairly uniform in color. 51.1407 Section 51.1407 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... in color. Fairly uniform in color means that the shells do not show sufficient variation in color...

  9. Laws of large numbers for ratios of uniform random variables

    Adler André

    2015-09-01

    Full Text Available Let {Xnn n ≥ 1} and {Yn, n ≥ 1} be two sequences of uniform random variables. We obtain various strong and weak laws of large numbers for the ratio of these two sequences. Even though these are uniform and naturally bounded random variables the ratios are not bounded and have an unusual behaviour creating Exact Strong Laws.

  10. 50 CFR 510.9 - Uniform pay guidelines.

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Uniform pay guidelines. 510.9 Section 510... ACT § 510.9 Uniform pay guidelines. (a) Compensation of members and staff of, and consultants to the... accordance with guidelines established by the Director of the Office of Management and Budget pursuant...

  11. 22 CFR 214.42 - Uniform pay guidelines.

    2010-04-01

    ... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Uniform pay guidelines. 214.42 Section 214.42... Advisory Committees § 214.42 Uniform pay guidelines. (a) A.I.D. follows OMB/CSC guidelines in section 11 of... experts, their compensation shall be fixed in accordance with CSC guidelines and regulations, and...

  12. 44 CFR 12.18 - Uniform pay guidelines.

    2010-10-01

    ... 44 Emergency Management and Assistance 1 2010-10-01 2010-10-01 false Uniform pay guidelines. 12.18 Section 12.18 Emergency Management and Assistance FEDERAL EMERGENCY MANAGEMENT AGENCY, DEPARTMENT OF HOMELAND SECURITY GENERAL ADVISORY COMMITTEES § 12.18 Uniform pay guidelines. (a) Members. Subject to...

  13. A directional uniformity of periodic point distribution and mixing

    Miles, R

    2010-01-01

    For mixing Z^d-actions generated by commuting automorphisms of a compact abelian group, we show that directional mixing and directional convergence of the uniform measure supported on periodic points to Haar measure occurs at a uniform rate independent of the direction. The proof exploits the tight connection between the adelic amoeba associated to the action and the dynamics.

  14. Uniform attractors of non-autonomous dissipative semilinear wave equations

    2003-01-01

    The asymptotic long time behaviors of a certain type of non-autonomous dissipative semilinear wave equations are studied. The existence of uniform attractors is proved and their upper bounds for both Hausdorff and Fractal dimensions of uniform are given when the external force satisfies suitable conditions.

  15. Measurement Method of the Thickness Uniformity for Polymer Films

    2003-01-01

    Several methods for investigating the thickness uniformity of polymer thin films are presented as well as their measurement principles. A comparison of these experimental methods is given.The cylindrical lightwave reflection method is found to can obtain the thickness distribution along a certain direction.It is a simple and suitable method to evaluate the film thickness uniformity.

  16. Evaluation of School Uniform Policy in Turkey: A Case Study

    Cinoglu, Mustafa

    2014-01-01

    The purpose of this study is to evaluate the results of current school uniform policies according to views of stakeholders. Descriptive case study method was used for this study to understand the concerns of the stakeholders about school uniforms. Data was collected through interviews with stakeholders and also reviewing the documents in TOKI…

  17. Effect of Uniformly and Nonuniformly Coated Al2O3 Nanoparticles over Glass Tube Heater on Pool Boiling

    Nitin Doifode

    2016-01-01

    Full Text Available Effect of uniformly and nonuniformly coated Al2O3 nanoparticles over plain glass tube heater on pool boiling heat transfer was studied experimentally. A borosilicate glass tube coated with Al2O3 nanoparticle was used as test heater. The boiling behaviour was studied by using high speed camera. Result obtained for pool boiling shows enhancement in heat transfer for nanoparticle coated surface heater and compared with plain glass tube heater. Also heat transfer coefficient for nonuniformly coated nanoparticles was studied and compared with uniformly coated and plain glass tube. Coating effect of nanoparticles over glass tube increases its surface roughness and thereby creates more nucleation sites.

  18. Uniformity of spherical shock wave dynamically stabilized by two successive laser profiles in direct-drive inertial confinement fusion implosions

    Temporal, M., E-mail: mauro.temporal@hotmail.com [Centre de Mathématiques et de Leurs Applications, ENS Cachan and CNRS, 61 Av. du President Wilson, F-94235 Cachan Cedex (France); Canaud, B. [CEA, DIF, F-91297 Arpajon Cedex (France); Garbett, W. J. [AWE plc, Aldermaston, Reading, Berkshire RG7 4PR (United Kingdom); Ramis, R. [ETSI Aeronáutica y del Espacio, Universidad Politécnica de Madrid, 28040 Madrid (Spain)

    2015-10-15

    The implosion uniformity of a directly driven spherical inertial confinement fusion capsule is considered within the context of the Laser Mégajoule configuration. Two-dimensional (2D) hydrodynamic simulations have been performed assuming irradiation with two laser beam cones located at 49° and 131° with respect to the axis of symmetry. The laser energy deposition causes an inward shock wave whose surface is tracked in time, providing the time evolution of its non-uniformity. The illumination model has been used to optimize the laser intensity profiles used as input in the 2D hydro-calculations. It is found that a single stationary laser profile does not maintain a uniform shock front over time. To overcome this drawback, it is proposed to use two laser profiles acting successively in time, in order to dynamically stabilize the non-uniformity of the shock front.

  19. MO-AB-BRA-08: Rapid Treatment Field Uniformity Optimization for Total Skin Electron Beam Therapy Using Cherenkov Imaging

    Andreozzi, J; Zhang, R; Glaser, A; Pogue, B [Dartmouth College, Hanover, NH (United States); Jarvis, L [Dartmouth-Hitchcock Medical Center, City Of Lebanon, New Hampshire (United States); Williams, B [Dartmouth Hitchcock Medical Center, Lebanon, NH (Lebanon); Gladstone, D [Dartmouth Hitchcock-Medical Center, Hanover, NH (United States)

    2015-06-15

    Purpose: To evaluate treatment field heterogeneity resulting from gantry angle choice in total skin electron beam therapy (TSEBT) following a modified Stanford dual-field technique, and determine a relationship between source to surface distance (SSD) and optimized gantry angle spread. Methods: Cherenkov imaging was used to image 62 treatment fields on a sheet of 1.2m x 2.2m x 1.2cm polyethylene following standard TSEBT setup at our institution (6 MeV, 888 MU/min, no spoiler, SSD=441cm), where gantry angles spanned from 239.5° to 300.5° at 1° increments. Average Cherenkov intensity and coefficient of variation in the region of interest were compared for the set of composite Cherenkov images created by summing all unique combinations of angle pairs to simulate dual-field treatment. The angle pair which produced the lowest coefficient of variation was further studied using an ionization chamber. The experiment was repeated at SSD=300cm, and SSD=370.5cm. Cherenkov imaging was also implemented during TSEBT of three patients. Results: The most uniform treatment region from a symmetric angle spread was achieved using gantry angles +/−17.5° about the horizontal axis at SSD=441cm, +/−18.5° at SSD=370.5cm, and +/−19.5° at SSD=300cm. Ionization chamber measurements comparing the original treatment spread (+/−14.5°) and the optimized angle pair (+/−17.5°) at SSD=441cm showed no significant deviation (r=0.999) in percent depth dose curves, and chamber measurements from nine locations within the field showed an improvement in dose uniformity from 24.41% to 9.75%. Ionization chamber measurements correlated strongly (r=0.981) with Cherenkov intensity measured concurrently on the flat Plastic Water phantom. Patient images and TLD results also showed modest uniformity improvements. Conclusion: A decreasing linear relationship between optimal angle spread and SSD was observed. Cherenkov imaging offers a new method of rapidly analyzing and optimizing TSEBT setup

  20. Spatial model of the gecko foot hair: functional significance of highly specialized non-uniform geometry

    Filippov, Alexander E.; Gorb, Stanislav N.

    2015-01-01

    One of the important problems appearing in experimental realizations of artificial adhesives inspired by gecko foot hair is so-called clusterization. If an artificially produced structure is flexible enough to allow efficient contact with natural rough surfaces, after a few attachment–detachment cycles, the fibres of the structure tend to adhere one to another and form clusters. Normally, such clusters are much larger than original fibres and, because they are less flexible, form much worse adhesive contacts especially with the rough surfaces. Main problem here is that the forces responsible for the clusterization are the same intermolecular forces which attract fibres to fractal surface of the substrate. However, arrays of real gecko setae are much less susceptible to this problem. One of the possible reasons for this is that ends of the seta have more sophisticated non-uniformly distributed three-dimensional structure than that of existing artificial systems. In this paper, we simulated three-dimensional spatial geometry of non-uniformly distributed branches of nanofibres of the setal tip numerically, studied its attachment–detachment dynamics and discussed its advantages versus uniformly distributed geometry. PMID:25657843

  1. Uniform dimension results of multi-parameter stable processes

    林火南

    1999-01-01

    The problem of uniform dimensions for multi-parameter processes, which may not possess the uniform stochastic H(?)lder condition, is investigated. The problem of uniform dimension for multi-parameter stable processes is solved. That is, if Z is a stable (N, d, α)-process and αN≤d, then (?)E(?)R_+~N, dimZ(E)=α·dimE holds with probability 1, where Z(E)={x:(?)t∈E, Z_t=x} is the image set of Z on E. The uniform upper bounds for multi-parameter processes with independent increments under general conditions are also given. Most conclusions about uniform dimension can be considered as special cases of our results.

  2. Attitude Towards Physics and Additional Mathematics Achievement Towards Physics Achievement

    Veloo, Arsaythamby; Nor, Rahimah; Khalid, Rozalina

    2015-01-01

    The purpose of this research is to identify the difference in students' attitude towards Physics and Additional Mathematics achievement based on gender and relationship between attitudinal variables towards Physics and Additional Mathematics achievement with achievement in Physics. This research focused on six variables, which is attitude towards…

  3. Integrating SPOT-VEGETATION 13-yr time series and land-surface modelling to forecast the terrestrial carbon dynamics in a changing climate - The VEGECLIM project: achievements and lessons learned

    Defourny, Pierre; Verbeeck, Hans; Moreau, Inès; De Weirdt, Marjolein; Verhegghen, Astrid; Kibambe-Lubamba, Jean-Paul; Jungers, Quentin; Maignan, Fabienne; Najdovski, Nicolas; Poulter, Benjamin; MacBean, Natasha; Peylin, Philippe

    2014-05-01

    Vegetation is a major carbon sink and is as such a key component of the international response to climate change caused by the build-up of greenhouse gases in the atmosphere. However, anthropogenic disturbances like deforestation are the primary mechanism that changes ecosystems from carbon sinks to sources, and are hardly included in the current carbon modelling approaches. Moreover, in tropical regions, the seasonal/interannual variability of carbon fluxes is still uncertain and a weak or even no seasonality is taken into account in global vegetation models. In the context of climate change and mitigation policies like "Reducing Emissions from Deforestation and Forest Degradation in Developing Countries" (REDD), it is particularly important to be able to quantify and forecast the vegetation dynamics and carbon fluxes in these regions. The overall objective of the VEGECLIM project is to increase our knowledge on the terrestrial carbon cycle in tropical regions and to improve the forecast of the vegetation dynamics and carbon stocks and fluxes under different climate-change and deforestation scenarios. Such an approach aims to determine whether the African terrestrial carbon balance will remain a net sink or could become a carbon source by the end of the century, according to different climate-change and deforestation scenarios. The research strategy is to integrate the information of the land surface characterizations obtained from 13 years of consistent SPOT-VEGETATION time series (land cover, vegetation phenology through vegetation indices such as the Enhanced Vegetation Index (EVI)) as well as in-situ carbon flux data into the process based ORCHIDEE global vegetation model, capable of simulating vegetation dynamics and carbon balance. Key challenge of this project was to bridge the gap between the land cover and the land surface model teams. Several improvements of the ORCHIDEE model have been realized such as a new seasonal leaf dynamics for tropical evergreen

  4. Improved electron transportation of dye-sensitized solar cells using uniform mixed CNTs-TiO{sub 2} photoanode prepared by a new polymeric gel process

    Bakhshayesh, A. M.; Mohammadi, M. R., E-mail: mrm41@cam.ac.uk; Masihi, N.; Akhlaghi, M. H. [Sharif University of Technology, Department of Materials Science and Engineering (Iran, Islamic Republic of)

    2013-09-15

    A new facile strategy for fabrication of high surface area electrode in the form of mixtures of coated carbon nanotubes (CNTs) and TiO{sub 2} nanoparticles with various weight ratios is reported. The so-called polymeric gel process was used to deposit thick film containing uniform distribution of TiO{sub 2} nanoparticles and coated CNTs with high porosity by dip coating for dye-sensitized solar cells (DSSCs) applications. Based on simultaneous differential thermal analysis, the minimum annealing temperature to obtain inorganic- and organic-free films was determined at 500 Degree-Sign C. X-ray diffraction analysis revealed that deposited films were composed of primary nanoparticles with crystallite size in the range 21-45 nm. Field emission scanning electron microscope images showed that deposited films had porous morphology containing uniform spherical particles with diameter around 2.5 {mu}m and coated CNTs with TiO{sub 2} nanoparticles (TNTs). The spherical particles were composed of small nanoparticles ({approx}60 nm), improving light scattering and dye loading of the DSSC. Moreover, TNTs were uniformly incorporated into the electrodes, improving electron transportation. X-ray photoelectron spectroscopy was presented as an obvious proof for the inclusion of CNTs into the TiO{sub 2} matrix. Ultraviolet-visible spectroscopy showed that CNT introduction enhanced the visible light absorption of photoanode by shifting the absorption onset to visible light region. An enhancement of power conversion efficiency (PCE) from 6.53 % for pure TiO{sub 2} to 7.38 % for CNT-TiO{sub 2} electrode containing 0.025 wt% CNTs was achieved. This well-incorporated study would present an intellectual development in the fabrication of low-cost CNT consolidated DSSCs with high PCE.

  5. Condensation on surface energy gradient shifts drop size distribution toward small drops.

    Macner, Ashley M; Daniel, Susan; Steen, Paul H

    2014-02-25

    During dropwise condensation from vapor onto a cooled surface, distributions of drops evolve by nucleation, growth, and coalescence. Drop surface coverage dictates the heat transfer characteristics and depends on both drop size and number of drops present on the surface at any given time. Thus, manipulating drop distributions is crucial to maximizing heat transfer. On earth, manipulation is achieved with gravity. However, in applications with small length scales or in low gravity environments, other methods of removal, such as a surface energy gradient, are required. This study examines how chemical modification of a cooled surface affects drop growth and coalescence, which in turn influences how a population of drops evolves. Steam is condensed onto a horizontally oriented surface that has been treated by silanization to deliver either a spatially uniform contact angle (hydrophilic, hydrophobic) or a continuous radial gradient of contact angles (hydrophobic to hydrophilic). The time evolution of number density and associated drop size distributions are measured. For a uniform surface, the shape of the drop size distribution is unique and can be used to identify the progress of condensation. In contrast, the drop size distribution for a gradient surface, relative to a uniform surface, shifts toward a population of small drops. The frequent sweeping of drops truncates maturation of the first generation of large drops and locks the distribution shape at the initial distribution. The absence of a shape change indicates that dropwise condensation has reached a steady state. Previous reports of heat transfer enhancement on chemical gradient surfaces can be explained by this shift toward smaller drops, from which the high heat transfer coefficients in dropwise condensation are attributed to. Terrestrial applications using gravity as the primary removal mechanism also stand to benefit from inclusion of gradient surfaces because the critical threshold size required for

  6. Extension of the modal wave-front reconstruction algorithm to non-uniform illumination.

    Ma, Xiaoyu; Mu, Jie; Rao, ChangHui; Yang, Jinsheng; Rao, XueJun; Tian, Yu

    2014-06-30

    Attempts are made to eliminate the effects of non-uniform illumination on the precision of wave-front measurement. To achieve this, the relationship between the wave-front slope at a single sub-aperture and the distributions of the phase and light intensity of the wave-front were first analyzed to obtain the relevant theoretical formulae. Then, based on the principle of modal wave-front reconstruction, the influence of the light intensity distribution on the wave-front slope is introduced into the calculation of the reconstruction matrix. Experiments were conducted to prove that the corrected modal wave-front reconstruction algorithm improved the accuracy of wave-front reconstruction. Moreover, the correction is conducive to high-precision wave-front measurement using a Hartmann wave-front sensor in the presence of non-uniform illumination.

  7. Uniform fabrication of Ge nanocrystals embedded into SiO2 film via neutron transmutation doping

    Wei Liu; Tiecheng Lu; Qingyun Chen; Youwen Hu; Shaobo Dun; Issai Shlimak

    2014-01-01

    Nanocrystalline 74Ge embedded SiO2 films were prepared by employing ion implantation and neutron transmutation doping methods. Transmission electron microscopy, energy dispersive x-ray spectroscopy, and photoluminescence of the obtained samples were measured. The existence of As dopants transmuted from 74Ge is significant to guarantee the uniformity and higher volume density of Ge nanocrystals by tuning the system's crystallinity and activating mass transfer process. It was observed that the photoluminescence intensity of Ge nanocrystals increased first then decreased with the increase of arsenic concentration. The optimized fluence of neutron transmutation doping was found to be 5.5 ? 1017 cm ? 2 to achieve maximum photoluminescence emission in Ge embedded SiO2 film. This work opens a route in the three-dimensional nanofabrication of uniform Ge nanocrystals.

  8. Uniform fabrication of Ge nanocrystals embedded into SiO2 film via neutron transmutation doping

    Wei Liu

    2014-06-01

    Full Text Available Nanocrystalline 74Ge embedded SiO2 films were prepared by employing ion implantation and neutron transmutation doping methods. Transmission electron microscopy, energy dispersive x-ray spectroscopy, and photoluminescence of the obtained samples were measured. The existence of As dopants transmuted from 74Ge is significant to guarantee the uniformity and higher volume density of Ge nanocrystals by tuning the system׳s crystallinity and activating mass transfer process. It was observed that the photoluminescence intensity of Ge nanocrystals increased first then decreased with the increase of arsenic concentration. The optimized fluence of neutron transmutation doping was found to be 5.5×1017 cm−2 to achieve maximum photoluminescence emission in Ge embedded SiO2 film. This work opens a route in the three-dimensional nanofabrication of uniform Ge nanocrystals.

  9. Droplet Merging on a Lab-on-a-Chip Platform by Uniform Magnetic Fields

    Varma, V. B.; Ray, A.; Wang, Z. M.; Wang, Z. P.; Ramanujan, R. V.

    2016-11-01

    Droplet microfluidics offers a range of Lab-on-a-chip (LoC) applications. However, wireless and programmable manipulation of such droplets is a challenge. We address this challenge by experimental and modelling studies of uniform magnetic field induced merging of ferrofluid based droplets. Control of droplet velocity and merging was achieved through uniform magnetic field and flow rate ratio. Conditions for droplet merging with respect to droplet velocity were studied. Merging and mixing of colour dye + magnetite composite droplets was demonstrated. Our experimental and numerical results are in good agreement. These studies are useful for wireless and programmable droplet merging as well as mixing relevant to biosensing, bioassay, microfluidic-based synthesis, reaction kinetics, and magnetochemistry.

  10. Weight uniformity of scored tablet halves manufactured by palestinian pharmaceutical companies.

    Zaid, A N; Abu, Ghosh A; Kittana, N

    2010-01-01

    The purpose of this study was to evaluate the weight uniformity of some commonly divided tablets produced by Palestinian Pharmaceutical companies. Volunteers were asked to divide scored tablets. The split units were individually weighed and the relative standard deviation for each product was calculated. Five scored tablet products failed the United States Pharmacopeia test of mass uniformity; this indicates that the splitting of these tablet products is not reliable for the provision of accurate doses. The practice of dividing tablets to achieve therapeutic and economic benefits for the patient may cause significant problems, especially in drugs with low therapeutic indices. Pharmacists may resolve this inconvenience by reformulating the tablet into a new dosage form, such as capsules, which should contain the exact amount of the medication.

  11. Electrical and optical characterization of an atmospheric pressure, uniform, large-area processing, dielectric barrier discharge

    Zeniou, A.; Puač, N.; Škoro, N.; Selaković, N.; Dimitrakellis, P.; Gogolides, E.; Petrović, Z. Lj

    2017-04-01

    A printed-circuit-board (PCB) based atmospheric pressure dielectric barrier discharge (DBD) capable of uniform processing over a large area was constructed consisting of two parallel plates. The first perforated plate is comprised of four layers: a RF powered metal layer, a polymeric dielectric layer, a floating metal grid and another dielectric layer. The second, grounded, plate was fluorine doped tin oxide (FTO) glass plate with surface of 100  ×  100 mm2 and thickness of 2 mm. The PCB based atmospheric pressure DBD was characterized by (a) measuring electrical characteristics of the device using derivative I–V probes, (b) ICCD imaging and (c) optical emission spectroscopy (OES). Optical and electrical characteristics, as well as plasma uniformity were measured by changing He flow rate and input power, while keeping the gap between the PCB and the FTO glass plate ground electrode constant at 2 mm. The plasma uniformity strongly depends on the applied power and on the flow rate of the buffer gas. When increasing the flow rate, the intensity of the nitrogen-dominated emission drops, while emission of helium and oxygen lines increases. The source allows low temperature, uniform plasma operation over a wide area of 100  ×  100 mm2, which could be essential for numerous applications. Examples of etching rate and hydrophilization are demonstrated.

  12. Improving uniformity in brain death determination policies over time

    Wang, Hilary H.; Varelas, Panayiotis N.; Henderson, Galen V.; Wijdicks, Eelco F.M.

    2017-01-01

    Objective: To demonstrate that progress has been made in unifying brain death determination guidelines in the last decade by directly comparing the policies of the US News and World Report's top 50 ranked neurologic institutions from 2006 and 2015. Methods: We solicited official hospital guidelines in 2015 from these top 50 institutions, generated summary statistics of their criteria as benchmarked against the American Academy of Neurology Practice Parameters (AANPP) and the comparison 2006 cohort in 5 key categories, and statistically compared the 2 cohorts' compliance with the AANPP. Results: From 2008 to 2015, hospital policies exhibited significant improvement (p = 0.005) in compliance with official guidelines, particularly with respect to criteria related to apnea testing (p = 0.009) and appropriate ancillary testing (p = 0.0006). However, variability remains in other portions of the policies, both those with specific recommendation from the AANPP (e.g., specifics for ancillary tests) and those without firm guidance (e.g., the level of involvement of neurologists, neurosurgeons, or physicians with education/training specific to brain death in the determination process). Conclusions: While the 2010 AANPP update seems to be concordant with progress in achieving greater uniformity in guidelines at the top 50 neurologic institutions, more needs to be done. Whether further interventions come as grassroots initiatives that leverage technological advances in promoting adoption of new guidelines or as top-down regulatory rulings to mandate speedier approval processes, this study shows that solely relying on voluntary updates to professional society guidelines is not enough. PMID:28077490

  13. A New Uniform Phase Bridge Functional: Test and Its Application to Non-uniform Phase Fluid

    ZHOU Shi-Qi; CHEN Hong; ZHANG Xiao-Qi

    2003-01-01

    A new bridge functional as a function of indirect correlation function was proposed, which was basedon analysis on the asymptotic behavior of the Ornstein-Zernike (OZ) equation system and a series expansion whoserenormalization resulted in an adjustable parameter determined by the thermodynamics consistency condition. Theproposed bridge functional was tested by applying it to bulk hard sphere and hard core Yukawa fluid for the predictionof structure and thermodynamics properties based on the OZ equation. As an application, the present bridge functionalwas employed for non-uniform fluid of the above two kinds by means of the density functional theory methodology, theresulting density distribution profiles were in good agreement with the available computer simulation data.

  14. Magnet-free uniform sputtering of dielectric film by RF and microwave power superposition

    Sasai, Kensuke; Hagihara, Toshiya; Noda, Tomonori; Suzuki, Haruka; Toyoda, Hirotaka

    2016-08-01

    A novel sputtering device that is free of magnets (magnet-free surface wave sputtering plasma: MF-SSP) is developed by combining a surface wave plasma and RF bias power. Low-pressure (<0.5 Pa) plasma sustainment is demonstrated by MF-SSP with a uniform sputter deposition rate with a deviation of less than 5% within an area of 10 × 10 cm2. Highly oriented MgO films are deposited at a substrate temperature of 200 °C.

  15. ODMedit: uniform semantic annotation for data integration in medicine based on a public metadata repository

    Martin Dugas

    2016-06-01

    Full Text Available Abstract Background The volume and complexity of patient data – especially in personalised medicine – is steadily increasing, both regarding clinical data and genomic profiles: Typically more than 1,000 items (e.g., laboratory values, vital signs, diagnostic tests etc. are collected per patient in clinical trials. In oncology hundreds of mutations can potentially be detected for each patient by genomic profiling. Therefore data integration from multiple sources constitutes a key challenge for medical research and healthcare. Methods Semantic annotation of data elements can facilitate to identify matching data elements in different sources and thereby supports data integration. Millions of different annotations are required due to the semantic richness of patient data. These annotations should be uniform, i.e., two matching data elements shall contain the same annotations. However, large terminologies like SNOMED CT or UMLS don’t provide uniform coding. It is proposed to develop semantic annotations of medical data elements based on a large-scale public metadata repository. To achieve uniform codes, semantic annotations shall be re-used if a matching data element is available in the metadata repository. Results A web-based tool called ODMedit ( https://odmeditor.uni-muenster.de/ was developed to create data models with uniform semantic annotations. It contains ~800,000 terms with semantic annotations which were derived from ~5,800 models from the portal of medical data models (MDM. The tool was successfully applied to manually annotate 22 forms with 292 data items from CDISC and to update 1,495 data models of the MDM portal. Conclusion Uniform manual semantic annotation of data models is feasible in principle, but requires a large-scale collaborative effort due to the semantic richness of patient data. A web-based tool for these annotations is available, which is linked to a public metadata repository.

  16. Controlled generation of uniform spherical LaMnO3, LaCoO3, Mn2O3, and Co3O4 nanoparticles and their high catalytic performance for carbon monoxide and toluene oxidation.

    Liu, Yuxi; Dai, Hongxing; Deng, Jiguang; Zhang, Lei; Zhao, Zhenxuan; Li, Xinwei; Wang, Yuan; Xie, Shaohua; Yang, Huanggen; Guo, Guangsheng

    2013-08-01

    Uniform hollow spherical rhombohedral LaMO3 and solid spherical cubic MOx (M = Mn and Co) NPs were fabricated using the PMMA-templating strategy. Hollow spherical LaMO3 and solid spherical MOx NPs possessed surface areas of 21-33 and 21-24 m(2)/g, respectively. There were larger amounts of surface-adsorbed oxygen species and better low-temperature reducibility on/of the hollow spherical LaMO3 samples than on/of the solid spherical MOx samples. Hollow spherical LaMO3 and solid spherical MOx samples outperformed their nanosized counterparts for oxidation of CO and toluene, with the best catalytic activity being achieved over the solid spherical Co3O4 sample for CO oxidation (T50% = 81 °C and T90% = 109 °C) at space velocity = 10,000 mL/(g h) and the hollow spherical LaCoO3 sample for toluene oxidation (T50% = 220 °C and T90% = 237 °C) at space velocity = 20,000 mL/(g h). It is concluded that the higher surface areas and oxygen adspecies concentrations and better low-temperature reducibility are responsible for the excellent catalytic performance of the hollow spherical LaCoO3 and solid spherical Co3O4 NPs. We believe that the PMMA-templating strategy provides an effective route to prepare uniform perovskite-type oxide and transition-metal oxide NPs.

  17. ZnO:Al thin films deposited by RF-magnetron sputtering with tunable and uniform properties.

    Miorin, E; Montagner, F; Battiston, S; Fiameni, S; Fabrizio, M

    2011-03-01

    Nanostructured, high quality and large area Al-doped ZnO (ZnO:Al) thin films were obtained by radiofrequency (RF) magnetron sputtering. The sample rotation during deposition has resulted in excellent spatial distribution of thickness and electro-optical properties compared to that obtained under static conditions. ZnO:Al thin films are employed in a large number of devices, including thin film solar cells, where the uniformity of the properties is a key factor for a possible up-scaling of the research results to industrially relevant substrate sizes. A chemical post etching treatment was employed achieving tunable surface nanotextures to generate light scattering at the desired wavelength for improved cell efficiency. Since the film resistivity is only slightly increased by the etching, this post-deposition step allows separating the optimization of electro-optical properties from light scattering behavior. The thin films were characterized by FE-SEM, XRD, UV-VIS spectroscopy, four probe and van der Paw techniques.

  18. An Ad Hoc Adaptive Hashing Technique forNon-Uniformly Distributed IP Address Lookup in Computer Networks

    Christopher Martinez

    2007-02-01

    Full Text Available Hashing algorithms long have been widely adopted to design a fast address look-up process which involves a search through a large database to find a record associated with a given key. Hashing algorithms involve transforming a key inside each target data to a hash value hoping that the hashing would render the database a uniform distribution with respect to this new hash value. The close the final distribution is to uniform, the less search time would be required when a query is made. When the database is already key-wise uniformly distributed, any regular hashing algorithm, such as bit-extraction, bit-group XOR, etc., would easily lead to a statistically perfect uniform distribution after the hashing. On the other hand, if records in the database are instead not uniformly distributed as in almost all known practical applications, then even different regular hash functions would lead to very different performance. When the target database has a key with a highly skewed distributed value, performance delivered by regular hashing algorithms usually becomes far from desirable. This paper aims at designing a hashing algorithm to achieve the highest probability in leading to a uniformly distributed hash result from a non-uniformly distributed database. An analytical pre-process on the original database is first performed to extract critical information that would significantly benefit the design of a better hashing algorithm. This process includes sorting on the bits of the key to prioritize the use of them in the XOR hashing sequence, or in simple bit extraction, or even a combination of both. Such an ad hoc hash design is critical to adapting to all real-time situations when there exists a changing (and/or expanding database with an irregular non-uniform distribution. Significant improvement from simulation results is obtained in randomly generated data as well as real data.

  19. Poisson-Boltzmann model of electrolytes containing uniformly charged spherical nanoparticles.

    Bohinc, Klemen; Volpe Bossa, Guilherme; Gavryushov, Sergei; May, Sylvio

    2016-12-21

    Like-charged macromolecules typically repel each other in aqueous solutions that contain small mobile ions. The interaction tends to turn attractive if mobile ions with spatially extended charge distributions are added. Such systems can be modeled within the mean-field Poisson-Boltzmann formalism by explicitly accounting for charge-charge correlations within the spatially extended ions. We consider an aqueous solution that contains a mixture of spherical nanoparticles with uniform surface charge density and small mobile salt ions, sandwiched between two like-charged planar surfaces. We perform the minimization of an appropriate free energy functional, which leads to a non-linear integral-differential equation for the electrostatic potential that we solve numerically and compare with predictions from Monte Carlo simulations. Nanoparticles with uniform surface charge density are contrasted with nanoparticles that have all their charges relocated at the center. Our mean-field model predicts that only the former (especially when large and highly charged particles) but not the latter are able to mediate attractive interactions between like-charged planar surfaces. We also demonstrate that at high salt concentration attractive interactions between like-charged planar surfaces turn into repulsion.

  20. Personal Exposure to Contaminant Sources in a Uniform Velocity Field

    Brohus, Henrik; Nielsen, Peter V.

    The objective of this study has been to determine the personal exposure to a contaminant source in a uniform velocity field. This was done by full-scale measurements and computer simulations. The results showed a significant dependence on the velocity field both regarding the direction and the ma...... the usual operation range. Guidelines for personal exposure reduction in a uniform velocity field are discussed.......The objective of this study has been to determine the personal exposure to a contaminant source in a uniform velocity field. This was done by full-scale measurements and computer simulations. The results showed a significant dependence on the velocity field both regarding the direction...

  1. Transverse vibrations of arbitrary non-uniform beams

    郭树起; 杨绍普

    2014-01-01

    Free and steady state forced transverse vibrations of non-uniform beams are investigated with a proposed method, leading to a series solution. The obtained series is verified to be convergent and linearly independent in a convergence test and by the non-zero value of the corresponding Wronski determinant, respectively. The obtained solution is rigorous, which can be reduced to a classical solution for uniform beams. The proposed method can deal with arbitrary non-uniform Euler-Bernoulli beams in principle, but the methods in terms of special functions or elementary functions can only work in some special cases.

  2. Generalized constrained multiobjective games in locally FC-uniform spaces

    DING Xie-ping; LEE Chin-san; YAO Jen-chih

    2008-01-01

    A new class of generalized constrained multiobjective games is introduced and studied in locally FC-uniform spaces without convexity structure where the number of players may be finite or infinite and all payoff functions get their values in an infinite-dimensional space.By using a Himmelberg type fixed point theorem in locally FC-uniform spaces due to author,some existence theorems of weak Pareto equilibria for the generalized constrained multiobjective games are established in locally FC-uniform spaces.These theorems improve,unify and generalize the corresponding results in recent literatares.

  3. A Generalization of Uniformly Extremely Convex Banach Spaces

    Suyalatu Wulede; Wurichaihu Bai; Wurina Bao

    2016-01-01

    We discuss a new class of Banach spaces which are the generalization of uniformly extremely convex spaces introduced by Wulede and Ha. We prove that the new class of Banach spaces lies strictly between either the classes of k-uniformly rotund spaces and k-strongly convex spaces or classes of fully k-convex spaces and k-strongly convex spaces and has no inclusive relation with the class of locally k-uniformly convex spaces. We obtain in addition some characterizations and properties of this ne...

  4. Constructing uniform color space in CIECAM97s

    2001-01-01

    The uniformity of two pairs of color spaces based on CIE 1997 color appearance model (CIECAM97s) is analyzed according to color-discrimination ellipses that are constructed using color-difference evaluation data. A new uniform color space named Jucs a ucs b ucs is deduced by re-scaling the coordinates of lightness, redness-greenness and vellowness-blueness in two initial color spaces using linear regression method. The uniformity of the new color space is obviously improved compared with the initial color spaces.

  5. Chemical vapor deposition reactor. [providing uniform film thickness

    Chern, S. S.; Maserjian, J. (Inventor)

    1977-01-01

    An improved chemical vapor deposition reactor is characterized by a vapor deposition chamber configured to substantially eliminate non-uniformities in films deposited on substrates by control of gas flow and removing gas phase reaction materials from the chamber. Uniformity in the thickness of films is produced by having reactive gases injected through multiple jets which are placed at uniformally distributed locations. Gas phase reaction materials are removed through an exhaust chimney which is positioned above the centrally located, heated pad or platform on which substrates are placed. A baffle is situated above the heated platform below the mouth of the chimney to prevent downdraft dispersion and scattering of gas phase reactant materials.

  6. UNIFORM PACKING DIMENSION RESULTS FOR MULTIPARAMETER STABLE PROCESSES

    2007-01-01

    In this article, authors discuss the problem of uniform packing dimension of the image set of multiparameter stochastic processes without random uniform H(o)lder condition, and obtain the uniform packing dimension of multiparameter stable processes.If Z is a stable (N, d, α)-process and αN ≤ d, then the following holds with probability 1 Dim Z(E) = α DimE for any Borel setE ∈ B(R+N),where Z(E) = {x: (E) t ∈ E, Z(t) = x}. Dim(E) denotes the packing dimension of E.

  7. The Moon Mineralogy (M3) Imaging Spectrometer: Early Assessment of the Spectral, Radiometric, Spatial and Uniformity Properties

    Green, Robert O.; Pieters, C. M.; Boardman, J.; Barr, D.; Bruce, C.; Bousman, J.; Chatterjee, A.; Eastwood, M.; Essandoh, V.; Geier, S.; Glavich, T.; Green, R.; Haemmerle, V.; Hyman, S.; Hovland, L.; Koch, T.; Lee, K.; Lundeen, S.; Motts, E.; Mouroulis, P.; Paulson, S.; Plourde, K.; Racho, C.; Robinson, D.; Rodriquez, J.

    2009-01-01

    The Moon Mineralogy Mapper's (M3) is a high uniformity and high signal-to-noise ratio NASA imaging spectrometer that is a guest instrument on the Indian Chandrayaan-1 Mission to the Moon. The laboratory measured spectral, radiometric, spatial, and uniformity characteristics of the M3 instrument are given. The M3 imaging spectrometer takes advantage of a suite of critical enabling capabilities to achieve its measurement requirement with a mass of 8 kg, power usage of 15 W, and volume of 25X18X12 cm. The M3 detector and spectrometer are cooled by a multi-stage passive cooler. This paper presents early M3 performance assessment results.

  8. Highly smooth Nb surfaces fabricated by buffered electropolishing

    Andy T. Wu; John Mammossor; H. Phillips; Jean Delayen; Charles Reece; Amy Wilkerson; David Smith; Robert Ike

    2005-05-01

    It is demonstrated that highly smooth Nb surfaces can be obtained through Buffered ElectroPolishing (BEP) employing an electrolyte consisting of lactic, sulfuric, and hydrofluoric acids. Parameters that control the polishing process are optimized to achieve the smoothest surface finish with the help of surface observations using a scanning electron microscope and a Metallographic Optical Microscope (MOM). The polishing rate of BEP is determined to be 0.646 {micro}m/min that is much higher than 0.381 {micro}m/min achieved by the conventional ElectroPolishing (EP) process widely used in the Superconducting Radio Frequency (SRF) community. A high precision and large scan area 3-D profilometer is used to view morphology of the treated Nb surfaces. Statistical data, such as, rms, total indicator runout, and arithmetic mean deviation of the Nb surfaces are extracted from the profilometer images. It is found that Nb surfaces treated by BEP are an order of magnitude smoother than those treated by the optimized EP process. The chemical composition of the Nb surfaces after BEP is analyzed by static and dynamic Secondary Ion Mass Spectrometer (SIMS) systems. Cracking patterns of the Nb surfaces under different primary ion sources of Ga{sup +}, Au{sup +}, and Ar{sup +} are reported. The depth profile of the surface niobium oxides is studied through continuously monitoring niobium and its relevant oxides' peaks as a function of time. Dynamic SIMS results imply that the surface oxide structure of Nb may be more complicated than what usually believed and can be inhomogeneous. Preliminary results of BEP on Nb SRF single cell cavities and half-cells are reported. It is shown that smooth and bright surfaces can be obtained in 30 minutes when the electric field inside a SRF cavity is uniform during a BEP process. This study reveals that BEP is a highly promising technique for surface treatment on Nb SRF cavities to be used in particle accelerators.

  9. Towards convective heat transfer enhancement: surface modification, characterization and measurement techniques

    Taha, T. J.; Thakur, D. B.; Van der Meer, T. H.

    2012-11-01

    In this work, heat transfer surface modification and heat transfer measurement technique is developed. Heat transfer investigation was aimed to study the effect of carbon nano fibers (extremely high thermal conductive material) on the enhancement level in heat transfer. Synthesis of these carbon nano structures is achieved using thermal catalytic chemical vapor deposition process (TCCVD) on a 50 μm pure nickel (Ni270) wire. The micro wire samples covered with CNF layers were subjected to a uniform flow from a nozzle. Heat transfer measurement was achieved by a controlled heat dissipation through the micro wire to attain a constant temperature during the flow. This measurement technique is adopted from hot wire anemometry calibration method. Synthesis of carbon nano structures, heat transfer surface characterization and measurement technique are evaluated. Preliminary results indicate that an average enhancement in Nusselt Number of 17% is achieved.

  10. Tunable shrink-induced honeycomb microwell arrays for uniform embryoid bodies.

    Nguyen, Diep; Sa, Silin; Pegan, Jonathan D; Rich, Brent; Xiang, Guangxin; McCloskey, Kara E; Manilay, Jennifer O; Khine, Michelle

    2009-12-07

    Embryoid body (EB) formation closely recapitulates early embryonic development with respect to lineage commitment. Because it is greatly affected by cell-cell and cell-substrate interactions, the ability to control the initial number of cells in the aggregates and to provide an appropriate substrate are crucial parameters for uniform EB formation. Here we report of an ultra-rapid fabrication and culture method utilizing a laser-jet printer to generate closely arrayed honeycomb microwells of tunable sizes for the induction of uniform EBs from single cell suspension. By printing various microwell patterns onto pre-stressed polystyrene sheets, and through heat induced shrinking, high aspect micromolds are generated. Notably, we achieve rounded bottom polydimethylsiloxane (PDMS) wells not easily achievable with standard microfabrication methods, but critical to achieve spherical EBs. Furthermore, by simply controlling the size of the microwells and the concentration of the cell suspension we can control the initial size of the cell aggregate, thus influencing lineage commitment. In addition, these microwells are easily adaptable and scalable to most standard well plates and easily integrated into commercial liquid handling systems to provide an inexpensive and easy high throughput compound screening platform.

  11. Non-uniform sampling of NMR relaxation data

    Schwarz-Linnet, Troels; Teilum, Kaare

    2016-01-01

    The use of non-uniform sampling of NMR spectra may give significant reductions in the data acquisition time. For quantitative experiments such as the measurement of spin relaxation rates, non-uniform sampling is however not widely used as inaccuracies in peak intensities may lead to errors...... in the extracted dynamic parameters. By systematic reducing the coverage of the Nyquist grid of (15)N Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion datasets for four different proteins and performing a full data analysis of the resulting non-uniform sampled datasets, we have compared the performance...... of the multi-dimensional decomposition and iterative re-weighted least-squares algorithms in reconstructing spectra with accurate peak intensities. As long as a single fully sampled spectrum is included in a series of otherwise non-uniform sampled two-dimensional spectra, multi-dimensional decomposition...

  12. Practical Non-Uniform Channelization for Multistandard Base Stations

    Alvaro Palomo Navarro; Rudi Villing; Ronan J. Farrell

    2011-01-01

    A multistandard software-defined radio base station must perform non-uniform channelization of multiplexed frequency bands. Non-uniform channelization accounts for a significant portion of the digital signal processing workload in the base station receiver and can be difficult to realize in a physical implementation. In non-uniform channelization methods based on generalized DFT filter banks, large prototype filter orders are a significant issue for implementation. In this paper, a multistage filter design is applied to two different non-uniform generalized DFT-based channelizers in order to reduce their filter orders. To evaluate the approach, a TETRA and TEDS base station is used. Experimental results show that the new multistage design reduces both the number of coefficients and operations and leads to a more feasible design and practical physical implementation.

  13. A uniform inf--sup condition with applications to preconditioning

    Mardal, Kent-Andre; Winther, Ragnar

    2012-01-01

    A uniform inf-sup condition related to a parameter dependent Stokes problem is established. Such conditions are intimately connected to the construction of uniform preconditioners for the problem, i.e., preconditioners which behave uniformly well with respect to variations in the model parameter as well as the discretization parameter. For the present model, similar results have been derived before, but only by utilizing extra regularity ensured by convexity of the domain. The purpose of this paper is to remove this artificial assumption. As a byproduct of our analysis, in the two dimensional case we also construct a new projection operator for the Taylor-Hood element which is uniformly bounded in $L^2$ and commutes with the divergence operator. This construction is based on a tight connection between a subspace of the Taylor-Hood velocity space and the lowest order Nedelec edge element.

  14. Waves in a Uniform Medium: Arbitrary Angle of Propagation

    Schnack, Dalton D.

    In Lecture 23, we showed that in an infinite, uniform medium, the solutions of the ideal MHD wave equation could be decomposed into plane wave solutions ξ _{{k}} e^{i(k \\cdot r + ω _k t)} that satisfy.

  15. Achieving monospermy or preventing polyspermy?

    Dale B

    2016-06-01

    Full Text Available Brian Dale Centre for Assisted Fertilization, Naples, Italy Abstract: Images of sea urchin oocytes with hundreds of spermatozoa attached to their surface have fascinated scientists for over a century and led to the idea that oocytes have evolved mechanisms to allow the penetration of one spermatozoon while repelling supernumerary spermatozoa. Popular texts have extrapolated this concept, to the mammals and amphibians, and in many cases to include all the Phyla. Here, it is argued that laboratory experiments, using sea urchin oocytes deprived of their extracellular coats and inseminated at high densities, are artifactual and that the experiments leading to the idea of a fast block to polyspermy are flawed. Under natural conditions, the number of spermatozoa at the site of fertilization is extremely low, compared with the numbers generated. The sperm:oocyte ratio is regulated first by dilution in externally fertilizing species and the female reproductive tract in those with internal fertilization, followed by a bottleneck created by the oocytes extracellular coats. In order to progress to the oocyte plasma membrane, the fertilizing spermatozoon must encounter and respond to a correct sequence of signals from the oocytes extracellular coats. Those that do not, are halted in their progression by defective signaling and fall to the wayside. Final success and entry is finely tuned by the spermatozoon anchoring to an actin-rich predetermined site on the plasma membrane. In this review, the variation in the form, function, and number of gametes produced across the animal kingdom and the many ways in which sperm–oocyte interactions are regulated to reduce numbers are discussed. Since in nature, final sperm:oocyte ratios approach unity it would appear that selective pressures have favored the achievement of monospermy, rather than the evolution of polyspermy preventing mechanisms. Keywords: monospermy, natural conditions, polyspermy, laboratory

  16. The Power Unit Coordinated Control via Uniform Differential Evolution

    Zain Abdalla Zahran; Rui Feng Shi; Xiang Jie Liu

    2013-01-01

    This paper modified the differential evolution (DE) algorithm adaptively to solve the power unit coordinated control (PUCC) problem. It was modified in two aspects: 1) a uniform initialization, which was controlled and regulated by a zone factor (m), 2) a regular mutation process, to develop an effective searching process and improve the convergence of the basic DE algorithm. A numerical case study was employed to verify the performance of our proposed uniform differential evolution (UDE) a...

  17. Automatic Sampling with the Ratio-of-uniforms Method

    Leydold, Josef

    1999-01-01

    Applying the ratio-of-uniforms method for generating random variates results in very efficient, fast and easy to implement algorithms. However parameters for every particular type of density must be precalculated analytically. In this paper we show, that the ratio-of-uniforms method is also useful for the design of a black-box algorithm suitable for a large class of distributions, including all with log-concave densities. Using polygonal envelopes and squeezes results in an algorithm that is ...

  18. Calculating Method of Moments Uniform Bin Width Histograms

    James S. Weber

    2016-01-01

    A clear articulation of Method of Moments (MOM) Histograms is instructive and has waited 121 years since 1895. Also of interest are enabling uniform bin width (UBW) shape level sets. Mean-variance MOM uniform bin width frequency and density histograms are not unique, however ranking them by histogram skewness compared to data skewness helps. Although theoretical issues rarely take second place to calculations, here calculations based on shape level sets are central and challenge uncritically ...

  19. Uniform large-area thermionic cathode for SCALPEL

    Katsap, Victor; Sewell, Peter B.; Waskiewicz, Warren K.; Zhu, Wei

    1999-11-01

    An electron beam lithography tool, which employs the SCALPEL technique, requires an extremely uniform beam to illuminate the scattering Mask, with the cathode operating in the temperature limited mode. It has been previously shown that LaB6 cathodes are not stable in this mode of operation. We have explored the possibility of implementing refined Tantalum-based emitters in the SCALPEL source cathode, and have developed large-area flat cathodes featuring suitably high emission uniformity under temperature limited operation.

  20. Uniformly Most Powerful Invariant Test and Its Application

    ZHANG Shuang-lin; SHA Qui-ying; ZHOU Wen-hai

    2001-01-01

    The authors consider the uniformly most powerful invariant test of the testing problems (Ⅰ)H0: μ′∑-1μ ≥ C H1: μ'∑-1μ < C and(Ⅱ) H00: ≥ C H11: <C under m-dimensional normal population Nm (μ, ∑ ) and normal linear model ( Y, Xβ, σ2 ) respectively.Furthermore, an application of the uniformly most powerful invariant test is given.

  1. Vibrating Breakup of Jet for Uniform Metal Droplets

    Shengdong GAO; Yingxue YAO; Chengsong CUI

    2007-01-01

    Uniform droplet formation from capillary stream breakup provides promising opportunities for many applications such as solder balls manufacturing, circuit board printing and rapid prototype manufacturing. In this study an apparatus capable of making monosize metal spheres by vibrating breakup has been developed. The droplets were electrically charged to avoid collision and merging with one another during flight. As a result, uniformly sized tin powders (180μm in diameter) were obtained after cooling and solidification.

  2. Continuity of Extremal Elements in Uniformly Convex Spaces

    Ferguson, Timothy

    2013-01-01

    In this paper, we study the problem of finding the extremal element for a linear functional over a uniformly convex Banach space. We show that a unique extremal element exists and depends continuously on the linear functional, and vice versa. Using this, we simplify and clarify Ryabykh's proof that for any linear functional on a uniformly convex Bergman space with kernel in a certain Hardy space, the extremal functional belongs to the corresponding Hardy space.

  3. On random flights with non-uniformly distributed directions

    De Gregorio, Alessandro

    2011-01-01

    This paper deals with a new class of random flights $\\underline{\\bf X}_d(t),t>0,$ defined in the real space $\\mathbb{R}^d, d\\geq 2,$ characterized by non-uniform probability distributions on the multidimensional sphere. These random motions differ from similar models appeared in literature which take directions according to the uniform law. The family of angular probability distributions introduced in this paper depends on a parameter $\

  4. Effects of a uniform acceleration on atom-field interactions

    Marino, Jamir; Passante, Roberto; Rizzuto, Lucia; Spagnolo, Salvatore

    2014-01-01

    We review some quantum electrodynamical effects related to the uniform acceleration of atoms in vacuum. After discussing the energy level shifts of a uniformly accelerated atom in vacuum, we investigate the atom-wall Casimir-Polder force for accelerated atoms, and the van der Waals/Casimir-Polder interaction between two accelerated atoms. The possibility of detecting the Unruh effect through these phenomena is also discussed in detail.

  5. Cpuf: Chirped-Pulse Microwave Spectroscopy in Pulsed Uniform Supersonic Flows

    Suits, Arthur; Abeysekera, Chamara; Zack, Lindsay N.; Joalland, Baptiste; Ariyasingha, Nuwandi M.; Park, Barratt; Field, Robert W.; Sims, Ian

    2015-06-01

    Chirped-pulse Fourier-transform microwave spectroscopy has stimulated a resurgence of interest in rotational spectroscopy owing to the dramatic reduction in spectral acquisition time it enjoys when compared to cavity-based instruments. This suggests that it might be possible to adapt the method to study chemical reaction dynamics and even chemical kinetics using rotational spectroscopy. The great advantage of this would be clear, quantifiable spectroscopic signatures for polyatomic products as well as the possibility to identify and characterize new radical reaction products and transient intermediates. To achieve this, however, several conditions must be met: 1) products must be thermalized at low temperature to maximize the population difference needed to achieve adequate signal levels and to permit product quantification based on the rotational line strength; 2) a large density and volume of reaction products is also needed to achieve adequate signal levels; and 3) for kinetics studies, a uniform density and temperature is needed throughout the course of the reaction. These conditions are all happily met by the uniform supersonic flow produced from a Laval nozzle expansion. In collaboration with the Field group at MIT we have developed a new instrument we term a CPUF (Chirped-pulse/Uniform Flow) spectrometer in which we can study reaction dynamics, photochemistry and kinetics using broadband microwave and millimeter wave spectroscopy as a product probe. We will illustrate the performance of the system with a few examples of photodissociation and reaction dynamics, and also discuss a number of challenges unique to the application of chirped-pulse microwave spectroscopy in the collisional environment of the flow. Future directions and opportunities for application of CPUF will also be explored.

  6. Uniformity of fuel target implosion in Heavy Ion Fusion

    Kawata, S; Suzuki, T; Karino, T; Barada, D; Ogoyski, A I; Ma, Y Y

    2015-01-01

    In inertial confinement fusion the target implosion non-uniformity is introduced by a driver beams' illumination non-uniformity, a fuel target alignment error in a fusion reactor, the target fabrication defect, et al. For a steady operation of a fusion power plant the target implosion should be robust against the implosion non-uniformities. In this paper the requirement for the implosion uniformity is first discussed. The implosion uniformity should be less than a few percent. A study on the fuel hotspot dynamics is also presented and shows that the stagnating plasma fluid provides a significant enhancement of vorticity at the final stage of the fuel stagnation. Then non-uniformity mitigation mechanisms of the heavy ion beam (HIB) illumination are also briefly discussed in heavy ion inertial fusion (HIF). A density valley appears in the energy absorber, and the large-scale density valley also works as a radiation energy confinement layer, which contributes to a radiation energy smoothing. In HIF a wobbling he...

  7. Highly uniform hole spacing micro brushes based on aligned carbon nanotube arrays

    Yang, Zhi; Zhu, Xingzhong; Huang, Xiaolu; Cheng, Yingwu; Liu, Yun; Geng, Huijuan; Wu, Yue; Su, Yanjie; Wei, Hao; Zhang, Yafei

    2013-11-01

    Highly uniform hole spacing micro brushes were fabricated based on aligned carbon nanotube (CNT) arrays synthesized by chemical vapor deposition method with the assistance of anodic aluminum oxide (AAO) template. Different micro brushes from CNT arrays were constructed on silicon, glass, and polyimide substrates, respectively. The micro brushes had highly uniform hole spacing originating from the regularly periodic pore structure of AAO template. The CNT arrays, serving as bristles, were firmly grafted on the substrates. The brushes can easily clean particles with scale of micrometer on the surface of silicon wafer and from the narrow spaces between the electrodes in a series of cleaning experiments. The results show the potential application of the CNT micro brushes as a cleaning tool in microelectronics manufacture field.

  8. Second-Order Solutions for Random Interfacial Waves Under Steady Uniform Currents

    SONG Jin-bao

    2005-01-01

    In the present research, the study of Song (2004) for random interfacial waves in two-layer fluid is extended to the case of fluids moving at different steady uniform speeds. The equations describing the random displacements of the density interface and the associated velocity potentials in two-layer fluid are solved to the second order, and the wave-wave interactions of the wave components and the interactions between the waves and currents are described. As expected, the extended solutions include those obtained by Song (2004) as one special case where the steady uniform currents of the two fluids are taken as zero, and the solutions reduce to those derived by Sharma and Dean (1979) for random surface waves if the density of the upper fluid and the current of the lower fluid are both taken as zero.

  9. A precise model of LED lighting and its application in uniform illumination system

    WU Feng-tie; HUANG Qi-lu

    2011-01-01

    Optical models directly effect the irradiance distribution of observed surface.Traditionally,approximate Lambertian models are widely used in designing the light-emitting diodes(LED) arrays in spite of their errors compared with the experimental data.But now a novel LED optical model for uniform illumination system has been proposed,in which the curvefitting technique is used to reduce the inherited errors and modify those previous models.The points from the curve of the LED light intensity are adopted,and a spline curve is designed for fitting,which obtains the revised mode.To verify its feasibility,we apply the new model in a 4 × 4 array design.The results show that compared with the approximate Lambertian,the light intensity distribution produced by the fitting model is more uniform and intense,as is expected.

  10. Improving the content uniformity of a low-dose tablet formulation through roller compaction optimization.

    am Ende, Mary T; Moses, Sara K; Carella, Anthony J; Gadkari, Rashmi A; Graul, Timothy W; Otano, Angel L; Timpano, Robert J

    2007-01-01

    In this investigation, the potency distribution of a low-dose drug in a granulation was optimized through a two-part study using statistically designed experiments. The purpose of this investigation was to minimize the segregation potential by improving content uniformity across the granule particle size distribution, thereby improving content uniformity in the tablet. Initial operating parameters on the Gerteis 3-W-Polygran 250/100/3 Roller Compactor resulted in a U-shaped potency function (potency vs. granule particle size) with superpotent fines and large granules. The roller compaction optimization study was carried out in two parts. Study I used a full factorial design with roll force (RF) and average gap width (GW) as independent variables and Study II used a D-optimal response surface design with four factors: RF, GW, granulating sieve size (SS), and granulator speed (GS). The planned response variables for Study I were bypass weight % and potency of bypass. Response variables for Study II included mean granulation potency with % relative standard deviation (% RSD), granulation particle size, sieve cut potency % RSD, tablet potency with % RSD, compression force at 7 kP crushing strength, and friability of 7-kP tablets. A constraint on GW was determined in Study I by statistical analysis. Bypass and observations of ribbon splitting were minimized when GW was less than 2.6 mm. In Study II, granulation potency, granulation uniformity, and sieve cut uniformity were optimized when the SS was 0.8 mm. Higher RF during dry granulation produced better sieve cut uniformity and tablets with improved uniformity throughout the run, as measured by stratified tablet samples taken during compression and assayed for potency. The recommended optimum roller compaction and milling operating parameters that simultaneously met all constraints were RF = 9 kN, GW = 2.3 mm, SS = 0.8 mm, and GS = 50 rpm. These parameters became the operating parameter set points during a model

  11. Statistical Mechanics Approach for Uniform and Non-uniform Fluid with Hard Core and Interaction Tail

    ZHOU Shi-Qi; CHEN Hong; LING Si-Li; XIANG Xian-Wei; ZHANG Xiao-Qi

    2003-01-01

    One recently proposed self-consistent hard sphere bridge functional was combined with an exponential function exp(-cr) and a re-normalized indirect correlation function to construct the bridge function for fluid with hard core and interaction tail. In the present approach, the adjustable parameter α was determined by the thermodynamic consistency realized on the compressibility modulus, the re-normalization of the indirect correlation function was realized by a modified Mayer function with the interaction potential replaced by the perturbative part of the interaction potential. As an example, the present bridge function was combined with the Ornstein-Zernike (OZ) equation to predict structure and thermodynamics properties in very good agreement with the simulation data available for Lennard-Jones (L J). Based on the universality principle of the free energy density functional and the test particle trick, the numerical solution of the OZ equation was employed to construct the first order direct correlation function of the non-uniform fluid as a functional of the density distribution by means of the indirect correlation function. In the framework of the density functional theory, the numerically obtained functional predicted the density distribution of LJ fluid confined in two planar hard walls that is in good agreement with the simulation data.

  12. Developable algebraic surfaces

    CHEN Dongren; WANG Guojin

    2004-01-01

    An algebraic surface can be defined by an implicit polynomial equation F(x,y,z)=0. In this paper, general characterizations of developable algebraic surfaces of arbitrary degree are presented. Using the shift operators of the subscripts of Bézier ordinates, the uniform apparent discriminants of developable algebraic surfaces to their Bézier ordinates are given directly. To degree 2 algebraic surfaces, which are widely used in computer aided geometric design and graphics, all possible developable surface types are obtained. For more conveniently applying algebraic surfaces of high degree to computer aided geometric design, the notion of ε-quasi-developable surfaces is introduced, and an example of using a quasi-developable algebraic surface of degree 3 to interpolate three curves of degree 2 is given.

  13. Identification of LPV Models with Non-uniformly Spaced Operating Points by Using Asymmetric Gaussian Weights

    Jie You; Qinmin Yang; Jiangang Lu; Youxian Sun

    2014-01-01

    In this paper, asymmetric Gaussian weighting functions are introduced for the identification of linear parameter varying systems by utilizing an input-output multi-model structure. It is not required to select operating points with uniform spacing and more flexibility is achieved. To verify the effectiveness of the proposed approach, sev-eral weighting functions, including linear, Gaussian and asymmetric Gaussian weighting functions, are evaluated and compared. It is demonstrated through simulations with a continuous stirred tank reactor model that the proposed approach provides more satisfactory approximation.

  14. An effect of dummy cathode on thickness uniformity in electroforming process

    Chul-Woo Park

    2014-01-01

    Full Text Available This study examines the solution for one of the most difficult problems of electroforming process “thickness deviation”. As an effective solution, an auxiliary electrode (dummy cathode is considered. Generally, the thickness of an edge plating area is almost twice the center area or greater. An auxiliary electrode (intentionally attached dummy cathode has helped to achieve more uniform thickness of the electroformed-nickel layer by preventing excessive electric charge. In addition, computer-aided analysis was performed to determine the optimal condition of electroforming process and to confirm the experimental result.

  15. An Applied Method for Designing Maximally Decimating Non-uniform Filter Banks

    2003-01-01

    Assembling individual line phase filters to form a multi-channel filter bank allows the synthesis filter to be similar to corresponding analysis filters, and the design calculation can be simple. The appropriate relations between synthesis filters and analysis filters eliminate most aliasing resulting from decimation in non-uniform maximally decimating filter banks, and LS algorithm and Remez algorithm are used to optimize the composite character. This design method can achieve approximate Perfect-Reconstruction. An example is given in which the general parameter filters with approximate line phase are used as units of a filter bank.

  16. Uniformity Studies of Scintillator Tiles directly coupled to SiPMs for Imaging Calorimetry

    Simon, Frank

    2010-01-01

    We present a novel geometry of scintillator tiles developed for fiberless coupling to silicon photomultipliers (SiPMs) for applications in highly granular calorimeters. A high degree of uniformity of the tile response over the full active area was achieved by a drilled slit at the coupling position of the photon sensor with 2 mm, 4 mm and 5.5 mm in height, width and depth. Detailed measurements of the response to penetrating electrons were performed for tiles with a lateral size of 3 x 3 cm^2 and thicknesses of 5 mm and 3 mm.

  17. High contrast ratio, high uniformity multiple quantum well spatial light modulators

    Huang Yuyang; Yang Chen; Yang Hui [Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083 (China); Liu, H C; Cui Guoxin; Bian Lifeng; Zhang Yaohui [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215125 (China); Wasilewski, Z R; Buchanan, M; Laframboise, S R, E-mail: yhzhang2006@sinano.ac.c [Institute for Microstructural Sciences, National Research Council, Ottawa K1A 0R6 (Canada)

    2010-03-15

    Our latest research results on GaAs-AlGaAs multiple quantum well spatial light modulators are presented. The thickness uniformity of the epitaxial layers across the 3-inch wafer grown by our molecular beam epitaxy is better than 0.1% and the variation of cavity resonance wavelength within the wafer is only 0.9 nm. A contrast ratio (CR) of 102 by varying bias voltage from 0 to 6.7 V is achieved after fine tuning the cavity by etching an adjust layer. Both theoretical and experimental results demonstrate that incorporating an adjust layer is an effective tuning method for obtaining high CR. (semiconductor integrated circuits)

  18. Mathematics Achievement in High- and Low-Achieving Secondary Schools

    Mohammadpour, Ebrahim; Shekarchizadeh, Ahmadreza

    2015-01-01

    This paper identifies the amount of variance in mathematics achievement in high- and low-achieving schools that can be explained by school-level factors, while controlling for student-level factors. The data were obtained from 2679 Iranian eighth graders who participated in the 2007 Trends in International Mathematics and Science Study. Of the…

  19. Investigation of differential surface removal due to electropolishing at JLab

    Marhauser, Frank [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Folkie, James [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Reece, Charles [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2015-09-01

    Surface chemistry carried out for Superconducting Radio Frequency (SRF) cavities such as Buffered Chemical Polishing (BCP) and Electropolishing (EP) aims to uniformly remove the internal surface of a cavity along the entire structure and within each cell from equator to iris in order to obtain an equally etched surface. A uniform removal, however, is not readily achievable due to the complex fluid flow and varying temperatures of the acid mixture, which can lead to differential etching. This needs to be considered when envisaging a certain surface damage removal throughout the interior. The process-specific differential etching influences the target frequency set at the manufacturing stage as well as the field flatness and length of the as-built cavity. We report on analyses of JLab's present EP system using experimental data for six nine-cell cavities that have been processed recently in the frame of the LCLS-II high-Q development plan. In conjunction with numerical simulations, the differential etching and the impact on field flatness is assessed.

  20. Is it reasonable to assume a uniformly distributed cooling-rate along the microslide of a directional solidification stage?

    Rabin

    2000-10-01

    It is commonly assumed that the cooling-rate along the microslide of a directional solidification stage is uniformly distributed, an assumption which is typically applied in low cooling-rates studies. A new directional solidification stage has recently been presented, which is specified to achieve high cooling-rates of up to 1.8 x 104 degrees C min-1, where cooling-rates are still assumed to be uniformly distributed. The current study presents a closed-form solution to the temperature distribution and to the cooling-rate in the microslide. Thermal analysis shows that the cooling-rate is by no means uniformly distributed and can vary by several hundred percent along the microslide in some cases. Therefore, the mathematical solution presented in this study is essential for experimental planning of high cooling-rate experiments.

  1. Design aspects of a compact, single-frequency, permanent magnet ECR ion source with a large uniformly distributed resonant plasma volume

    Liu, Y.; Alton, G.D.; Mills, G.D.; Reed, C.A.; Haynes, D.L.

    1997-09-01

    A compact, all-permanent-magnet single-frequency ECR ion source with a large uniformly distributed ECR plasma volume has been designed and is presently under construction at the Oak Ridge National Laboratory (ORNL). The central region of the field is designed to achieve a flat-field (constant mod-B) which extends over the length of the central field region along the axis of symmetry and radially outward to form a uniformly distributed ECR plasma volume. The magnetic field design strongly contrasts with those used in conventional ECR ion sources where the central field regions are approximately parabolic and the consequent ECR zones are surfaces. The plasma confinement magnetic field mirror has a mirror ratio B{sub max}/B{sub ECR} of slightly greater than two. The source is designed to operate at a nominal RF frequency of 6 GHz. The central flat magnetic field region can be easily adjusted by mechanical means to tune the source to the resonant conditions within the limits of 5.5 to 6.8 GHz. The RF injection system is broadband to ensure excitation of transverse electric (TE) modes so that the RF power is largely concentrated in the resonant plasma volume which lies along and surrounds the axis of symmetry of the source. Because of the much larger ECR zone, the probability for absorption of microwave power is dramatically increased thereby increasing the probability for acceleration of electrons, the electron temperature of the plasma and, consequently, the hot electron population within the plasma volume of the source. The creation of an ECR volume rather than a surface is commensurate with higher charge states and higher beam intensities within a particular charge state.

  2. Exceptional family of elements and the solvability of complementarity problems in uniformly smooth and uniformly convex Banach spaces

    ISAC G.; LI Jin-lu

    2005-01-01

    The notion of"exceptional family of elements (EFE)" plays a very important role in solving complementarity problems. It has been applied in finite dimensional spaces and Hilbert spaces by many authors. In this paper, by using the generalized projection defined by Alber, we extend this notion from Hilbert spaces to uniformly smooth and uniformly convex Banach spaces,and apply this extension to the study of nonlinear complementarity problems in Banach spaces.

  3. Improving heating uniformity of pathological tissue specimens inside a domestic microwave oven.

    Hassan, Osama A; Kandil, Ahmed H; El Bialy, Ahmed M; Hassaballa, Iman A

    2013-01-01

    A 3D coupled electromagnetic thermal model was developed using COMSOL 4.0 to predict the electromagnetic field distribution and temperature profile in pathological tissue samples immersed in a reagent inside the oven cavity. The effect of the volume of reagent on the mean heating rate and heating uniformity within the tissue sample was investigated. Also, the effect of using a water load, as a method of temperature control, is emphasized. A well insulated K type thermocouple connected to a PC is used for model validation. Good agreement is found between experimental and simulated temperature profiles. Results show that as the volume of reagent increases, the mean heating rate decreases and temperature homogeneity increases. Also, it is possible to minimize overshooting temperature values inside the tissue sample and enhance tissue uniformity by about 27% using 100 ml of water load and 42.26% using 150 ml. Domestic microwave oven is a low cost economical tool that can speed up tissue processing steps. Achieving uniform heating inside the microwave oven is the key factor for improving workflow inside pathological labs and maintaining tissue quality and integrity.

  4. Multiple tube structure for heating uniformity and efficiency optimization of microwave ovens

    Zhou, Rong; Yang, Xiaoqing; Sun, Di; Jia, Guozhu

    2015-02-01

    Microwave heating is widely applied to microwave assisted chemical reactions in modified domestic microwave ovens, however, the potential issues (non-uniformity and low heating efficiency) still exist during the heating process. In this paper, a new heating model of multiple tube structure is proposed and the relevant simulations and experiments of heating water were performed based on the computational platform COMSOL Multi-physics software in order to achieve the better temperature uniformity and heating efficiency. Besides, the influence of the instability of microwave ovens on the heating performances of the optimal heating models was analyzed. The simulation results show that the heating uniformity and efficiency of water in optimal six tube structure increased by 7.1% and 68.5% (30 mL), 9.2% and 61% (60 mL) respectively compared with the optimal single tube structure. Moreover, the heating performances of the optimal heating models do not change obviously, while the working frequency and power change slightly. The simulation results are in good agreement with the experiment data.

  5. Conditions for uniform impact of the plasma of a runaway-electron-induced pulsed diffuse discharge on an anode

    Erofeev, M. V.; Baksht, E. Kh.; Burachenko, A. G.; Tarasenko, V. F.

    2015-09-01

    The subject matters in this work are (i) the spatial structure of a volume (diffuse) discharge initiated in atmospheric-pressure air in a heavily nonuniform electric field by nanosecond voltage pulses and (ii) the influence of its plasma on the surface of a plane aluminum anode. It is shown that a diffuse discharge initiated by nanosecond voltage pulses makes it possible to uniformly process the anode's surface in atmospheric-pressure air in contrast to a spark discharge, which results in microcracking, locally changes the surface properties, and thereby degrades the surface.

  6. Luminescent Surface Quaternized Carbon Dots

    Bourlinos, Athanasios B.

    2012-01-10

    Thermal oxidation of a salt precursor made from the acid base combination of tris(hydroxymethyl)aminomethane and betaine hydrochloride results in light-emitting surface quaternized carbon dots that are water-dispersible, display anion exchange properties, and exhibit uniform size/surface charge. © 2011 American Chemical Society.

  7. Surface-enhanced Raman nanodomes

    Choi, Charles J; Xu Zhida; Wu, Hsin-Yu; Liu, Gang Logan; Cunningham, Brian T, E-mail: bcunning@illinois.edu [Department of Electrical and Computer Engineering, Micro and Nanotechnology Laboratory, University of Illinois at Urbana-Champaign, 208 North Wright Street, Urbana, IL 61801 (United States)

    2010-10-15

    We demonstrate a surface-enhanced Raman scattering (SERS) substrate consisting of a closely spaced metal nanodome array fabricated on flexible plastic film. We used a low-cost, large-area replica molding process to produce a two-dimensional periodic array of cylinders that is subsequently overcoated with SiO{sub 2} and silver thin films to form dome-shaped structures. Finite element modeling was used to investigate the electromagnetic field distribution of the nanodome array structure and the effect of the nanodome separation distance on the electromagnetic field enhancement. The SERS enhancement from the nanodome array substrates was experimentally verified using rhodamine 6G as the analyte. With a separation distance of 17 nm achieved between adjacent domes using a process that is precisely controlled during thin film deposition, a reproducible SERS enhancement factor of 1.37 x 10{sup 8} was demonstrated. The nanoreplica molding process presented in this work allows for simple, low-cost, high-throughput fabrication of uniform nanoscale SERS substrates over large surface areas without the requirement for high resolution lithography or defect-free deposition of spherical microparticle monolayer templates.

  8. MEASUREMENT OF NON-UNIFORM RESIDUAL STRESSES BY COMBINED MOIRE INTERFEROMETRY AND HOLE-DRILLING METHOD: THEORY, EXPERIMENTAL METHOD AND APPLICATIONS

    亚敏; 戴福隆; 谢惠民; 吕坚

    2003-01-01

    Hole-drilling method is one of the most convenient methods for engineering residual ment data, hole-drilling technique can be used to solve non-uniform residual stress problems, both (MIIHD) for non-uniform residual stress measurement is introduced. Three dimensional finite element model is constructed by ABAQUS to obtain the coefficients for the residual stress calculation.An experimental system including real-time measurement, automatic data processing and residual stresses calculation is established. Two applications for non-uniform in-depth residual stress of surface nanocrystalline material and non-uniform in-plane residual stress of friction stir welding are presented.Experimental results show that MIIHD is effective for both non-uniform in-depth and in-plane residual stress measurements.

  9. Characterization of uniform scanning proton beams with analytical models

    Demez, Nebi

    Tissue equivalent phantoms have an important place in radiation therapy planning and delivery. They have been manufactured for use in conventional radiotherapy. Their tissue equivalency for proton beams is currently in active investigation. The Bragg-Kleeman rule was used to calculate water equivalent thickness (WET) for available tissue equivalent phantoms from CIRS (Norfolk, VA, USA). WET's of those phantoms were also measured using proton beams at Hampton University Proton Therapy Institute (HUPTI). WET measurements and calculations are in good agreement within ˜1% accuracy except for high Z phantoms. Proton beams were also characterized with an analytical proton dose calculation model, Proton Loss Model (PLM) [26], to investigate protons interactions in water and those phantoms. Depth-dose and lateral dose profiles of protons in water and in those phantoms were calculated, measured, and compared. Water Equivalent Spreadness (WES) was also investigated for those phantoms using the formula for scattering power ratio. Because WES is independent of incident energy of protons, it is possible to estimate spreadness of protons in different media by just knowing WES. Measurements are usually taken for configuration of the treatment planning system (TPS). This study attempted to achieve commissioning data for uniform scanning proton planning with analytical methods, PLM, which have been verified with published measurements and Monte Carlo calculations. Depth doses and lateral profiles calculated by PLM were compared with measurements via the gamma analysis method. While gamma analysis shows that depth doses are in >90% agreement with measured depth doses, the agreement falls to <80% for some lateral profiles. PLM data were imported into the TPS (PLM-TPS). PLM-TPS was tested with different patient cases. The PLM-TPS treatment plans for 5 prostate cases show acceptable agreement. The Planning Treatment Volume (PTV) coverage was 100 % with PLM-TPS except for one case in

  10. Carbides composite surface layers produced by (PTA)

    Tajoure, Meloud, E-mail: Tajoore2000@yahoo.com [MechanicalEng.,HIHM,Gharian (Libya); Tajouri, Ali, E-mail: Tajouri-am@yahoo.com, E-mail: dr.mokhtarphd@yahoo.com; Abuzriba, Mokhtar, E-mail: Tajouri-am@yahoo.com, E-mail: dr.mokhtarphd@yahoo.com [Materials and Metallurgical Eng., UOT, Tripoli (Libya); Akreem, Mosbah, E-mail: makreem@yahoo.com [Industrial Research Centre,Tripoli (Libya)

    2013-12-16

    The plasma transferred arc technique was applied to deposit a composite layer of nickel base with tungsten carbide in powder form on to surface of low alloy steel 18G2A type according to polish standard. Results showed that, plasma transferred arc hard facing process was successfully conducted by using Deloro alloy 22 plus tungsten carbide powders. Maximum hardness of 1489 HV and minimum dilution of 8.4 % were achieved by using an arc current of 60 A. However, when the current was further increased to 120 A and the dilution increases with current increase while the hardness decreases. Microstructure of the nickel base deposit with tungsten carbide features uniform distribution of reinforcement particles with regular grain shape half - dissolved in the matrix.

  11. Peer relationships and academic achievement

    Krnjajić Stevan B.

    2002-01-01

    Full Text Available After their childhood, when children begin to establish more intensive social contacts outside family, first of all, in school setting, their behavior i.e. their social, intellectual, moral and emotional development is more strongly affected by their peers. Consequently, the quality of peer relationships considerably affects the process of adaptation and academic achievement and their motivational and emotional attitude towards school respectively. Empirical findings showed that there is bi-directional influence between peer relationships and academic achievement. In other words, the quality of peer relationships affects academic achievement, and conversely, academic achievement affects the quality of peer relationships. For example, socially accepted children exhibiting prosocial, cooperative and responsible forms of behavior in school most frequently have high academic achievement. On the other hand, children rejected by their peers often have lower academic achievement and are a risk group tending to delinquency, absenteeism and drop out of school. Those behavioral and interpersonal forms of competence are frequently more reliable predictors of academic achievement than intellectual abilities are. Considering the fact that various patterns of peer interaction differently exert influence on students' academic behavior, the paper analyzed effects of (a social competence, (b social acceptance/rejection, (c child's friendships and (d prosocial behavior on academic achievement.

  12. Healthy Eating and Academic Achievement

    2014-12-09

    This podcast highlights the evidence that supports the link between healthy eating and improved academic achievement. It also identifies a few actions to support a healthy school nutrition environment to improve academic achievement.  Created: 12/9/2014 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 12/9/2014.

  13. Physical Activity and Academic Achievement

    2014-12-09

    This podcast highlights the evidence that supports the link between physical activity and improved academic achievement. It also identifies a few actions to support a comprehensive school physical activity program to improve academic achievement.  Created: 12/9/2014 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 12/9/2014.

  14. Sociocultural Origins of Achievement Motivation

    Maehr, Martin L.

    1977-01-01

    Presents a theoretical review of work on sociocultural influences on achievement, focusing on a critical evaluation of the work of David McClellan. Offers an alternative conception of achievement motivation which stresses the role of contextual and situational factors in addition to personality factors. Available from: Transaction Periodicals…

  15. Parental Involvement and Academic Achievement

    Goodwin, Sarah Christine

    2015-01-01

    This research study examined the correlation between student achievement and parent's perceptions of their involvement in their child's schooling. Parent participants completed the Parent Involvement Project Parent Questionnaire. Results slightly indicated parents of students with higher level of achievement perceived less demand or invitations…

  16. A proof of the uniform boundedness of solutions to the wave equation on slowly rotating Kerr backgrounds

    Dafermos, Mihalis

    2008-01-01

    We consider Kerr spacetimes with parameters a and M such that |a|0, with appropriate geometric assumptions on the plane spanned by the Killing fields. We show uniform boundedness on the exterior for sufficiently regular solutions to the scalar homogeneous wave equation. In particular, the bound holds up to and including the event horizon. No unphysical restrictions are imposed on the behaviour of the solution near the bifurcation surface of the event horizon. The pointwise estimate derives in fact from the uniform boundedness of a positive definite energy flux. Note that in view of the very general assumptions, the separability properties of the wave equation on the Kerr background are not used.

  17. Effect of non-uniform magnetic field on crystal growth by floating-Zone method in microgravity

    李凯; 胡文瑞

    2001-01-01

    The magnetic damping effect of the non-uniform magnetic field on the floating-zone crystal growth process in microgravity is studied by numerical simulation. The results show that the non-uni-form magnetic field with designed configuration can effectively reduce the flow near the free surface and then in the melt zone. At the same time, the designed magnetic field can improve the impurity concen-tration non-uniformity along the solidification interface. The primary principles of the magnetic field con-figuration design are also discussed.

  18. Analyzing the uniformity of the generated magnetic field by a practical one-dimensional Helmholtz coils system.

    Beiranvand, R

    2013-07-01

    Using the Helmholtz coils system is one of the most suitable approaches which have been introduced for generating uniform magnetic fields. In this paper, uniformity of the generated magnetic field by a practical one-dimensional (1D) Helmholtz coils system has been analyzed, mathematically. For this purpose, relationships between the magnetic field uniformity and different practical unavoidable mismatches have been extracted. The theoretical analysis clearly demonstrates the effect of assembly misalignments and manufacturing mismatches on the magnetic field achieved by a practical 1D Helmholtz coils system. The given analyses have been confirmed by the experimental results which are in good agreement with the calculated values. This analysis and the experimental results illustrate that to achieve a very high uniform magnetic field, practical assembly misalignments, and manufacturing mismatches must be as small as possible, and the background magnetic field distortion must be avoided, too. The results of this work are important in the design of instruments and systems where Helmholtz coils are used.

  19. Non-uniform sampling of NMR relaxation data

    Linnet, Troels E.; Teilum, Kaare, E-mail: kaare.teilum@bio.ku.dk [University of Copenhagen, SBiNLab and the Linderstrøm-Lang Centre for Protein Science, Department of Biology (Denmark)

    2016-02-15

    The use of non-uniform sampling of NMR spectra may give significant reductions in the data acquisition time. For quantitative experiments such as the measurement of spin relaxation rates, non-uniform sampling is however not widely used as inaccuracies in peak intensities may lead to errors in the extracted dynamic parameters. By systematic reducing the coverage of the Nyquist grid of {sup 15}N Carr-Purcell-Meiboom-Gill (CPMG) relaxation dispersion datasets for four different proteins and performing a full data analysis of the resulting non-uniform sampled datasets, we have compared the performance of the multi-dimensional decomposition and iterative re-weighted least-squares algorithms in reconstructing spectra with accurate peak intensities. As long as a single fully sampled spectrum is included in a series of otherwise non-uniform sampled two-dimensional spectra, multi-dimensional decomposition reconstructs the non-uniform sampled spectra with high accuracy. For two of the four analyzed datasets, a coverage of only 20 % results in essentially the same results as the fully sampled data. As exemplified by other data, such a low coverage is in general not enough to produce reliable results. We find that a coverage level not compromising the final results can be estimated by recording a single full two-dimensional spectrum and reducing the spectrum quality in silico.

  20. Enhanced Deposition Uniformity via an Auxiliary Electrode in Massive Electrospinning.

    Wu, Dezhi; Xiao, Zhiming; Deng, Lei; Sun, Yu; Tan, Qiulin; Dong, Linxi; Huang, Shaohua; Zhu, Rui; Liu, Yifang; Zheng, Wanxi; Zhao, Yang; Wang, Lingyun; Sun, Daoheng

    2016-07-22

    Uniform deposition of nanofibers in the massive electrospinning process is critical in the industrial applications of nanofibers. Tip-Induced Electrospinning (TIE) is a cost-effective large-scale nanofiber-manufacturing method, but it has poor deposition uniformity. An auxiliary conductive electrode connected to the emitting electrode was introduced to improve the deposition uniformity of the nanofibers. The effects of the auxiliary electrode shape, the tilted angles and the position of the boat-like electrode on the electric field distribution, the diameter of the nanofibers, the jet control and the deposition uniformity were explored by using finite element analysis of the electric field and experiments. Experiments showed that the boat-like electrode at 20 mm above the reservoir bottom with a 5° tilted angle helped to decrease the relative deposition error of nanofibers in the greatest extent to about 5.66%, indicating such an auxiliary electrode is a good candidate method to greatly improve the deposition uniformity of nanofibers in massive electrospinning.