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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

    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. Uniform reflective films deposited on large surfaces

    1966-01-01

    Specially designed baffle which intercepts varying amounts of the vapor stream from an evaporant source, vacuum deposits films of uniform thickness on large substrates, using a single small area evaporation source. A mirror coated by this method will have a reflectance as high as 82 percent at 1216 angstroms with a variation of only plus/minus 2 percent over the surface.

  5. 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.

  6. 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…

  7. 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...

  8. Mandatory Uniform Dress Code Implementation and the Impact on Attendance, Achievement, and Perceptions of Classroom Environment

    Ward, Ella Porter

    1999-01-01

    One of the many attempts to solve problems that plague America's schools is the implementation of uniform dress code policies. Those who favor uniforms contend that uniforms will increase attendance, enhance academic achievement, and improve classroom environment. Prior research studies ( Behling, 1991; Hughes, 1996; and Hoffler-Riddick, 1998) on the effects of mandatory school uniforms have been inconclusive in their findings. The purpose of this study was to examine the impact of mandatory...

  9. Controlled Uniform Coating from the Interplay of Marangoni Flows and Surface-Adsorbed Macromolecules

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

    2016-03-01

    Surface coatings and patterning technologies are essential for various physicochemical applications. In this Letter, we describe key parameters to achieve uniform particle coatings from binary solutions. First, multiple sequential Marangoni flows, set by solute and surfactant simultaneously, prevent nonuniform 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.

  10. Dressed for Success? The Effect of School Uniforms on Student Achievement and Behavior

    Elisabetta Gentile; 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 and time. By including student and school fixed-effects we find evidence that uniform adoption improves attendance in secondary grades, while in el...

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

    Brunsma, David L.; Rockquemore, Kerry A.

    1998-01-01

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

  12. 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.

  13. Uniform surface complexation approaches to radionuclide sorption modeling

    Simplified surface complexation models, based on a uniform set of model parameters have been developed to address complex radionuclide sorption behavior. Existing data have been examined, and interpreted using numerical nonlinear least-squares optimization techniques to determine the necessary binding constants. Simplified modeling approaches have generally proven successful at simulating and predicting radionuclide sorption on (hydr)oxides and aluminosilicates over a wide range of physical and chemical conditions

  14. 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. PMID:26669496

  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. 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.

  17. 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…

  18. Surface Wave Plasma Driven by Ring Dielectric Line for Producing Dense, Large Area, Uniform Plasmas

    Matsumoto, Naoki

    1999-10-01

    Surface Wave excited Plasma (SWP), has been put into practice as a plasma source for the fabrication process of ULSI and LCD devices. This plasma has several advanced features: 1) Very high electron density with relatively low electron temperature; 2) Very uniform plasma density over large areas; 3) Operation from gas pressure of few mT to the order of thousands of mT. We present a newly developed microwave driven surface wave plasma source called a Ring Dielectric Line (RDL). The RDL is a metal ring wave-guide, filled with dielectric material, driven by a microwave. Slots for coupling the microwave power are symmetrically arrayed under the dielectric, facing towards the processing chamber. The electromagnetic power generates an electromagnetic surface wave, which in turn excites a plasma surface wave on the bottom side of the quartz plate in the processing chamber. In terms of its plasma characteristics, the uniformly distributed argon plasma with wide range of pressure of 20, 40 and 80mT as well as with high density about 5×10^17/m^3 over the cutoff density was observed. The electron temperature was about 2eV. In addition, in the 5000-minutes continuous running test for C_4F8 etching, it achieved repeatability of +/-0.7% and non-uniformity of about +/-3%.

  19. 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.

  20. Uniform regularity for the free surface compressible Navier-Stokes equations with or without surface tension

    Mei, Yu; Wang, Yong; Xin, Zhouping

    2015-01-01

    In this paper, we investigate the uniform regularity of solutions to the 3-dimensional isentropic compressible Navier-Stokes system with free surfaces and study the corresponding asymptotic limits of such solutions to that of the compressible Euler system for vanishing viscosity and surface tension. It is shown that there exists an unique strong solution to the free boundary problem for the compressible Navier-Stokes system in a finite time interval which is independent of the viscosity and t...

  1. 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...

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

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

    2001-02-01

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

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

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

  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

    2015-05-01

    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. PMID:25969321

  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. Capacity achieving nonbinary LDPC coded non-uniform shaping modulation for adaptive optical communications.

    Lin, Changyu; Zou, Ding; Liu, Tao; Djordjevic, Ivan B

    2016-08-01

    A mutual information inspired nonbinary coded modulation design with non-uniform shaping is proposed. Instead of traditional power of two signal constellation sizes, we design 5-QAM, 7-QAM and 9-QAM constellations, which can be used in adaptive optical networks. The non-uniform shaping and LDPC code rate are jointly considered in the design, which results in a better performance scheme for the same SNR values. The matched nonbinary (NB) LDPC code is used for this scheme, which further improves the coding gain and the overall performance. We analyze both coding performance and system SNR performance. We show that the proposed NB LDPC-coded 9-QAM has more than 2dB gain in symbol SNR compared to traditional LDPC-coded star-8-QAM. On the other hand, the proposed NB LDPC-coded 5-QAM and 7-QAM have even better performance than LDPC-coded QPSK. PMID:27505775

  7. 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.

  8. Gold colloidal nanoparticle electrodeposition on a silicon surface in a uniform electric field

    Buttard, D; Oelher, F; David, T

    2011-01-01

    The electrodeposition of gold colloidal nanoparticles on a silicon wafer in a uniform electric field is investigated using scanning electron microscopy and homemade electrochemical cells. Dense and uniform distributions of particles are obtained with no aggregation. The evolution of surface particle density is analyzed in relation to several parameters: applied voltage, electric field, exchanged charge. Electrical, chemical, and electrohydrodynamical parameters are taken into account in descr...

  9. 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. PMID:21920528

  10. Timing and Code Size Optimization on Achieving Full Parallelism in Uniform Nested Loops

    Elloumi, Yaroub; Bedoui, Mohamed Hedi

    2012-01-01

    Multidimensional Retiming is one of the most important optimization techniques to improve timing parameters of nested loops. It consists in exploring the iterative and recursive structures of loops to redistribute computation nodes on cycle periods, and thus to achieve full parallelism. However, this technique introduces a large overhead in a loop generation due to the loop transformation. The provided solutions are generally characterized by an important cycle number and a great code size. It represents the most limiting factors while implementing them in embedded systems. In this paper, we present a new Multidimensional Retiming technique, called "Optimal Multidimensional Retiming" (OMDR). It reveals the timing and data dependency characteristics of nodes, to minimize the overhead. The experimental results show that the average improvement on the execution time of the nested loops by our technique is 19.31% compared to the experiments provided by an existent Multidimensional Retiming Technique. The average ...

  11. Electroosmotic flow in Hele-Shaw configurations with non-uniform surface charge

    Boyko, Evgeniy; Gat, Amir D; Bercovici, Moran

    2015-01-01

    We present an analytical study, validated by numerical simulations, of electroosmotic flow in a Hele-Shaw cell with non-uniform surface charge patterning. Applying the lubrication approximation and assuming thin electric double layer, we obtain a pair of uncoupled Poisson equations which relate the pressure and the stream function, respectively, to gradients in the zeta potential distribution parallel and perpendicular to the applied electric field. We solve the governing equations for the fundamental case of a disk with uniform zeta potential and show that the flow-field in the outer region takes the form of a pure dipole. We illustrate the ability to generate complex flow-fields around smooth convex regions by superposition of such disks with uniform zeta potential and a uniform pressure driven flow. This method may be useful for future on-chip devices, allowing flow control without the need for mechanical components.

  12. Application and Refinement of a Method to Achieve Uniform Convective Response on Variable-Resolution Meshes

    Walko, R. L.; Medvigy, D.; Avissar, R.

    2013-12-01

    Variable-resolution computational grids can substantially improve the benefit-to-cost ratio in many environmental modeling applications, but they can also introduce unwanted and unrealistic numerical anomalies if not properly utilized. For example, we showed in previous studies that resolved (non-parameterized) atmospheric convection develops more quickly as resolution increases. Furthermore, on variable grids that transition from resolved to parameterized convection, timing and intensity of the convection in both regimes is generally disparate unless special care is taken to tune the parameterization. In both cases, the convection that develops first (due to purely numerical reasons) tends to suppress convection elsewhere by inducing subsidence in the surrounding environment. This highly nonlinear competition, while desirable when induced by natural causes such as surface inhomogeneity, is highly undesirable when it is a numerical artifact of variable grid resolution and/or selective application of convective parameterization. Our current research is aimed at leveling the playing field for convection across a variable resolution grid so that the above problems are avoided. The underlying idea is to apply the same or very similar 'convective machinery' to all areas of the grid. For convection-resolving regions of the grid, this machinery is simply the model grid itself, along with explicit representation of dynamics and a bulk microphysics parameterization. For coarser regions of the grid, the local environment is sampled from one or more grid columns (depending on local resolution) and fed to a separate 'convective processor', which determines the convective response to that environment and feeds the result back to the host grid. The convective processor chooses to either (1) explicitly resolve convective activity in the given environment on a separate (independent) limited-area 3D computational grid of comparable resolution to the convection-resolving part of the

  13. Observation of non-uniformity of space potential on magnetic surfaces in helical nonneutral plasmas

    It is observed, for the first time, that the space potential is non-uniform on magnetic surfaces in nonneutral helical plasmas. Electron plasmas are generated in a stellarator magnetic field by injection from an electron gun. Electrons are launched out with the acceleration voltage (Vacc) from 300 V to 1 kV. The potential non-uniformity is almost proportional to Vacc. Experimental errors such as missalignment of the measurement probe and the perturbing effect of probe insertion are carefully checked, and confirmed not to be the reason of the observed potential variation. (author)

  14. A two-dimensional cold atmospheric plasma jet array for uniform treatment of large-area surfaces for plasma medicine

    For plasma treatment of inanimate surfaces and living tissues in medicine, it is important to control plasma-sample interactions and to mitigate non-uniform treatments of usually uneven sample surfaces so that effectiveness of application can be reproduced for different biological samples, relatively independently of their varying surface topologies and material characters. This paper reports a scalable two-dimensional (2D) array of seven cold atmospheric plasma (CAP) jets intended to achieve these two important requirements as well as to address the unique challenge of jet-jet interactions. While the CAP jet array can be configured to interact with a biological sample in either a direct mode (used with an in situ sample) or a remote mode (used as an afterglow), this study focuses on the direct mode. Using a downstream planar electrode as a sample model, the spatial distribution of reactive species and electrons delivered by individual jets of the 2D CAP jet array attains excellent uniformity. Specifically, the spatial variation over 100 μs is 5.6 and 7.9%, respectively, for wavelength-integrated optical emission intensity, and for atomic oxygen emission intensity at 845 nm when the oxygen admixture is 0.5% of the helium carrier gas. It is also shown that the highest emission intensity at 845 nm occurs at O2/He=0.5% under the best jet-jet uniformity conditions for O2/He=0.3-0.7%. These results indicate the potential of 2D CAP jet arrays for uniform treatment and for effective control of jet-jet interactions. Furthermore, spatial uniformity is accompanied by rich dynamics of jet-jet interactions and jet-sample interactions. Of the honeycomb-arranged seven CAP jets, the central jet is strongest in the negative half cycle, whereas the six surrounding jets (of uniform strength) are strongest in the positive half cycle. These dynamic features offer possible insights with which to better control jet-jet interactions and plasma-surface interactions in future.

  15. 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.

  16. Free surface waves on shear currents with non-uniform vorticity: third-order solutions

    Free surface waves of moderate amplitude on a fluid endowed with vorticity are calculated by computer-assisted perturbation expansions. Solitary waves are generated by deriving the nonlinear evolution equation (NEE) for the free surface displacement. Another recursive iteration procedure is then performed on the NEE. Properties obtained from second- and third-order expansions are computed explicitly for the case of a linear shear profile, or uniform vorticity distribution. Comparisons with known results in the literature show excellent agreement for small amplitude waves. Applications to non-uniform vorticity distributions are feasible and valuable, as existing methods will generally fail for nonlinear shear currents. Algebraic shear profiles U(y) = aym (a = a constant, m not necessarily an integer) are tested, and backward modes display peculiar properties. Examples include a non-monotonic trend in the half-width of solitary waves and a local maximum in the velocity of the wave.

  17. Radiation flaw detector for testing non-uniform surface bodies of revolution

    Radiation flaw detector for testing bodies of revolution with non-uniform surface, welded joints, etc., based on spatial filtration and differentiation of ionizing radiation flux has been described. The calculation of the most important unit of flaw detector - integrators - is made. Experimental studies of the sensitivity have shown, that the radiation flaw detector can be used for rapid testing of products with the sensitivity comparable with the sensitivity of radiographic testing of steel

  18. 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.

  19. A uniformly valid asymptotic solution of the surface wave problem due to underwater sources

    The two-dimensional linearized problem of surface waves in water of finite (or infinite) depth due to a stationary periodic source situated at a finite depth below the free surface, is considered. The formal solution of the problem is derived by using Laplace and Fourier transforms. A uniformly valid asymptotic expansion of the wave integral is obtained by using the method of Bleistein in the case of finite depth and that of Vander Waerden in the case of infinite depth. Physical interpretation of the results so derived is given. (author)

  20. 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.

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

    Wu, Heng; Zhang, Xianmin; Ge, Peng

    2015-10-01

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

  2. The effect of surface finish on uniform corrosion of stainless steels in supercritical water

    Full text of publication follows: In the supercritical water-cooled reactor (SCWR) concept, coolant temperatures between 280 C and 620 C at 25 MPa are expected. Materials selection criteria concern high temperature yield stress, creep resistance, no embrittlement and resistance to both uniform corrosion and stress corrosion cracking. Here we will present results of a comparative study of uniform corrosion in SCW of austenitic stainless steels after exposure to deaerated SCW at 610 C and 25 MPa. The effect of different surface finishes (metallographic polish, as-machined and shot peened) will be described. For polished surfaces, observations of cross-sections reveal that two-layer oxides were formed. The outer oxide seems to grow due to cation diffusion, whereas anion diffusion would be responsible for the inner oxide layer. For as-machined 316L and 304 steels the oxide films are some 50 times thinner than for polished surfaces and consist essentially of chromia. It is suggested that fast oxidation in supercritical water requires sufficient available chromium in order to lead to a protective oxide film. There would then be a competition between chromium consumption through oxidation and chromium diffusion to the interface. Either the damaged sub-surface region or the ensuing recrystallised ultra fine grains could lead to enhanced chromium diffusion. This work leads to the definition of conditions leading to the formation of thin oxide films in supercritical water

  3. Sorption modelling by Gibbs energy minimisation: towards a uniform thermodynamic database for surface complexes of radionuclides

    Radionuclide sorption on mineral-water interfaces can be thermodynamically modelled, similar to solid-solution aqueous-solution systems (only in chemical elemental stoichiometry), if definitions of the standard and reference states, surface activity terms (SAT), and elemental stoichiometries of surface-bound species are unequivocally established. A pre-requisite is that a unique common value of the reference (site) density (Γo) must be part of the definitions of standard and reference states, while the sample- and surface-specific maximum density parameters (Γmax) be included into the SAT corrections to reproduce saturation of physically available adsorption sites instead of introducing the additional mass balance constraints. Subsequently, the standard partial molal properties of surface complexes at multiple surface types on different sorbents can be found, comparable with the standard molar properties of solids, gases and aqueous species. Using surface complexation models (SCM) of U(VI) adsorption on quartz and amorphous silica (SiO2) phases in GEM (Gibbs energy minimization) implementation, a feasible way is shown how to construct a uniform, internally consistent thermodynamic dataset for surface species of radionuclides; to use standard partial molal Gibbs energies G298o of surface species in sorption modelling; how to convert G298o values from/to log K or intrinsic adsorption constants log Kint to use in the law-of-mass action (LMA) speciation codes, and finally, into ''smart Kd'' values for the applications related to waste repository performance assessment. (orig.)

  4. The influence of non-uniform incident flux upon surface erosion processes

    The surface topographic development by sputter erosion of a solid resulting from spatially non-uniform projectile bombardment is considered theoretically. It is shown that whilst formal prediction of time-dependent surface geometry is possible, analytic solution of the defining equations is generally unachievable, although an approximate treatment may be made for the case of a Gaussian flux distribution profile and an initially plane surface. It is shown that profile perturbations resulting from erosion rate-projectile incidence angle variations can assume importance when erosion crater depths become of similar order to projectile beam width. This behaviour is also revealed by computer simulation of the erosion process and a sand blasting experimental analogue study. (author)

  5. Critical thickness of an optimum extended surface characterized by uniform heat transfer coefficient

    Leontiou, Theodoros

    2015-01-01

    We consider the heat transfer problem associated with a periodic array of extended surfaces (fins) subjected to convection heat transfer with a uniform heat transfer coefficient. Our analysis differs from the classical approach as (i) we consider two-dimensional heat conduction and (ii) the base of the fin is included in the heat transfer process. The problem is modeled as an arbitrary two-dimensional channel whose upper surface is flat and isothermal, while the lower surface has a periodic array of extensions/fins which are subjected to heat convection with a uniform heat transfer coefficient. Using the generalized Schwarz-Christoffel transformation the domain is mapped onto a straight channel where the heat conduction problem is solved using the boundary element method. The boundary element solution is subsequently used to pose a shape optimization problem, i.e. an inverse problem, where the objective function is the normalized Shape Factor and the variables of the optimization are the parameters of the Sch...

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

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

  7. Surface wave propagation over slowly varying media oftopography and non-uniform three-dimensional currents

    2000-01-01

    The influence of ambient current fields on the mild-slope approximation is reassessed using theHamiltonian variational principle. Considering the slowly modulated non-uniform currents which may possess both verti-cal and horizontal variations, the extended mild-slope equation for surface waves propagating over slowly varying topogra-phy is derived. It is found that for large current velocities comparable to the wave celerity and the group velocity, the ex-tended mild-slope equation is valid. For the validity of the geometric optics-approximation, additional conditions con-cerning current fields should be satisfied.

  8. The forced convection flow of a uniform stream over a flat surface with a convective surface boundary condition

    Merkin, J. H.; Pop, I.

    2011-09-01

    The forced convection heat transfer resulting from the flow of a uniform stream over a flat surface on which there is a convective boundary condition is considered. In previous papers [5-8] it was assumed that the convective heat transfer parameter hf associated with the hot surface depended on x, where x measures distance along the surface, so that problem could be reduced to similarity form. Here it is assumed that this heat transfer parameter hf is a constant, with the result that the temperature profiles and overall heat transfer characteristics evolve as the solution develops from the leading edge. The heat transfer near the leading edge (small x), which we find to be dominated by the surface heat flux, the solution at large distances along the surface (large x), which dominated by the surface temperature, are discussed. A numerical solution to the full problem is then obtained for a range of values of the Prandtl number to join these two solution regimes.

  9. Designing power heterojunction bipolar transistors with non-uniform emitter finger lengths to achieve high thermal stability

    With the aid of a thermal-electrical model, a practical method for designing multi-finger power heterojunction bipolar transistors with finger lengths divided in groups is proposed. The method can effectively enhance the thermal stability of the devices without sacrificing the design time. Taking a 40-finger heterojunction bipolar transistor for example, the device with non-uniform emitter finger lengths is optimized and fabricated. Both the theoretical and the experimental results show that, for the optimum device, the peak temperature is lowered by 26.19 K and the maximum temperature difference is reduced by 56.67% when compared with the conventional heterojunction bipolar transistor with uniform emitter finger length. Furthermore, the ability to improve the uniformity of the temperature profile and to expand the thermal stable operation range is strengthened as the power level increases, which is ascribed to the improvement of the thermal resistance in the optimum device. A detailed design procedure is also summarized to provide a general guide for designing power heterojunction bipolar transistors with non-uniform finger lengths. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  10. 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.

  11. Development of uniform methodical documents on monitoring radioactive contamination of soil, atmosphere, surface waters

    Full text: During performance of the Program of joint activity by overcoming consequences of accident on the Chernobyl NPP within the limits of the Union state for 2002-2005 normative and technical documents on monitoring radioactive contamination of an environment have been created uniform for two states. The package includes three base techniques of radiation monitoring soil, surface waters and atmospheres. Directing Institution by development of techniques from Belarus was the Republican center of Radiation Control and Environmental Monitoring (RCRCM), from Russia - Science and Production Association 'Typhoon' (SPA 'Typhoon'). Techniques regulate sequence of operations at sampling soil, water and air at carrying out of radioactive monitoring; describe the order of preparation of sample and carrying out of measurements (gamma-spectrometer, beta- alpha-metric and radiochemical). In techniques recommended methods and means of sampling of soil, water, air are in details described. For standardization of techniques on monitoring radioactive contamination of surface waters, atmospheres, soil have been lead precision experiments (PE). RCRCM, Belarus state university, Institute of radiobiology of the National Academy of Sciences of Belarus, Belarus State institute of metrology, SPA 'Typhoon' (Russia) took part in PE. Programs PE have been developed. Control samples with various levels of activity of tests of water, aerosol filters and soil have been prepared in RCRKM. Interlaboratory experiments according to accuracy of techniques performance measurements (TPM) for an establishment of the attributed characteristics of components of an error (regular and casual) with simultaneous check of adequacy (suitability) TPM are lead. Processing of results PE has been made. Parameters of accuracy of techniques on monitoring radioactive contamination of water, atmospheres and soil are certain. During carrying out PE of laboratory-participants have brought necessary corrective

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

    Hou, H.Q.; Choquette, K.D.; Hammons, B.E.; Breiland, W.G.; Crawford, M.H.; Lear, K.L. [Sandia National Labs., Albuquerque, NM (United States). Center for Compound Semiconductors Technology

    1997-05-01

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

  13. 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.

  14. 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…

  15. Exact computation of the expectation surfaces for uniform crossover along with bit-flip mutation

    Chicano, Francisco; Whitley, Darrell; Alba, Enrique

    2014-01-01

    Uniform crossover and bit-flip mutation are two popular operators used in genetic algorithms to generate new solutions in an iteration of the algorithm when the solutions are represented by binary strings. We use the Walsh decomposition of pseudo-Boolean functions and properties of Krawtchouk matrices to exactly compute the expected value for the fitness of a child generated by uniform crossover followed by bit-flip mutation from two parent solutions. We prove that this expectation is a polyn...

  16. The use of mould-templated surface structures for high-quality uniform-lying-helix liquid-crystal alignment

    Outram, B. I.; Elston, S. J.; Tuffin, R.; Siemianowski, S.; Snow, B.

    2013-06-01

    The chiral-flexoelectrooptic effect in a Uniform Lying Helix (ULH) configuration provides a sub-millisecond in-plane rotation of the optic axis with the application of a transverse field. This enables displays with a wide viewing angle without costly in-plane-type electrodes. The salient challenge is one of alignment of the ULH, which is not topologically compatible with uniform alignment surface treatments. Here, we create a micro-grooved surface structure with features on the micron scale by using a replica-moulding technique. When the cell is assembled, the micro-grooves create channels, and using surface-energy considerations, we explain how and show experimentally that the channels align a cholesteric material in the ULH geometry with the helicoidal axis oriented parallel to the channels. The resultant alignment provides a high level of contrast between crossed polarizers and exhibits an electrooptic response with a switching time of the order of tens of microseconds.

  17. Numerical study of an uniformly accessible plane surface in a steady laminar Newtonian fluid flow; Etude numerique d'une surface plane uniformement accessible dans un ecoulement permanent et laminaire d'un fluide newtonien

    Kabouche, N.; Benkhaled, A.; Mbow, C.; Daguenet, M. [Universite de Perpignan, Lab. de Thermodynamique et Energetique, 66 - Perpignan (France)

    2002-05-01

    The authors show numerically that a plane surface situated in the middle of a conduct, whose walls are equilateral hyperbolic surfaces, is uniformly accessible from a small distance of the entrance when a Newtonian fluid runs in steady laminar flow inside the conduct. They specify this distance according to the values of Reynolds and Prandtl numbers and to the ratio factor of the conduct. Calculations concern the heat transfer but are available for mass transfer by replacing the Prandtl and Nusselt numbers and the temperature respectively by the Schmidt and Sherwood numbers and the concentration of the diffusing substance. (authors)

  18. Uniform surface modification of diatomaceous earth with amorphous manganese oxide and its adsorption characteristics for lead ions

    Li, Song; Li, Duanyang; Su, Fei; Ren, Yuping; Qin, Gaowu, E-mail: lis@atm.neu.edu.cn

    2014-10-30

    Graphical abstract: - Highlights: • A uniform MnO{sub 2} layer was anchored onto diatomite surface. • Kinetics and isotherms over MnO{sub 2} modified diatomite were studied. • The Pb(II) adsorption is based on ion-exchange mechanism. - Abstract: A novel method to produce composite sorbent material compromising porous diatomaceous earth (DE) and surface functionalized amorphous MnO{sub 2} is reported. Via a simple in situ redox reaction over the carbonized DE powders, a uniform layer of amorphous MnO{sub 2} was anchored onto the DE surface. The hybrid adsorbent was characterized by X-ray diffraction, scanning electron microscopy, and infrared spectroscopy. The batch method has been employed to investigate the effects of surface coating on adsorption performance of DE. According to the equilibrium studies, the adsorption capacity of DE for adsorbing lead ions after MnO{sub 2} modification increased more than six times. And the adsorption of Pb{sup 2+} on the MnO{sub 2} surface is based on ion-exchange mechanism. The developed strategy presents a novel opportunity to prepare composite adsorbent materials by integrating nanocrystals with porous matrix.

  19. 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...

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

    Pourali, N.; Foroutan, G.

    2016-07-01

    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.

  1. Natural convection flow of Cu-H2O nanofluid along a vertical wavy surface with uniform heat flux

    Habiba, Farjana; Molla, Md. Mamun; Khan, M. A. Hakim

    2016-07-01

    A numerical study on natural convection flow of Cu-Water nanofluid along a vertical wavy surface with uniform heat flux has been carried out. The governing boundary layer equations are transformed into parabolic partial differential equations by applying a suitable set of variables. The resulting nonlinear system of equations are then mapped into a regular rectangular computational domain and solved numerically by using an implicit finite difference method. Numerical results are thoroughly discussed in terms of velocity and temperature distributions, surface temperature distribution, skin friction coefficient and Nusselt number coefficient for selected key parameters such as solid volume fraction of nanofluid (ϕ) and amplitude (α) of surface waviness. In addition, velocity vectors, streamlines and isotherms are plotted to visualize momentum and thermal flow pattern within the boundary layer region.

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

    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.

  3. 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.

  4. 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.

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

    Tang, Junqi; Zhao, Qianrun; Zhang, Ning; Man, Shi-Qing, E-mail: man_shiqing@yahoo.com

    2014-07-01

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

  6. Rigorous surface enhanced Raman spectral characterization of large-area high-uniformity silver-coated tapered silica nanopillar arrays

    Gartia, Manas R.; Xu, Zhida; Behymer, Elaine; Nguyen, Hoang; Britten, Jerald A.; Larson, Cindy; Miles, Robin; Bora, Mihail; S-P Chang, Allan; Bond, Tiziana C.; Logan Liu, G.

    2010-10-01

    Surface enhanced Raman spectroscopy (SERS) has been increasingly utilized as an analytical technique with significant chemical and biological applications (Qian et al 2008 Nat. Biotechnol. 26 83; Fujita et al 2009 J. Biomed. Opt. 14 024038; Chou et al 2008 Nano Lett.8 1729; Culha et al 2003 Anal. Chem. 75 6196; Willets K A 2009 Anal. Bioanal. Chem. 394 85; Han et al 2009 Anal. Bioanal. Chem. 394 1719; Sha et al 2008 J. Am. Chem. Soc. 130 17214). However, production of a robust, homogeneous and large-area SERS substrate with the same ultrahigh sensitivity and reproducibility still remains an important issue. Here, we describe a large-area ultrahigh-uniformity tapered silver nanopillar array made by laser interference lithography on the entire surface of a 6 inch wafer. Also presented is the rigorous optical characterization method of the tapered nanopillar substrate to accurately quantify the Raman enhancement factor, uniformity and repeatability. An average homogeneous enhancement factor of close to 108 was obtained for benzenethiol adsorbed on a silver-coated nanopillar substrate.

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

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

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

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

    2007-04-01

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

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

    Nagare, S [Technofarm Axesz Co., Ltd., 4-4-27-703 Aobadai, Meguro, Tokyo 153-0042 (Japan); Sagawa, Jo [Faculty of Science and Technology, Keio University, 3-14-1, Hiyoshi, Yokohama 223-8522 (Japan); Senna, M [Technofarm Axesz Co., Ltd., 4-4-27-703 Aobadai, Meguro, Tokyo 153-0042 (Japan)

    2007-04-15

    Pulsed laser deposition (PLD) of drug nanoparticles for pharmaceutical preparation was investigated. Indomethacin (IM) was preliminary mixed with magnesium stearate (StMg) to prepare a target for PLD. By using the composite targets, the percentage of deposited nanoparticles in the collected powder increased compared to when only IM was ablated. The percentage of IM nanoparticles was the highest when IM and StMg were mixed at 1:1 ratio. Nanoparticles of the composite target were deposited on the micron sized particulate excipient, i.e., SiO{sub 2}, potato starch, and lactose. The excipient powders were mixed by rotation. Their surface coverage was evaluated by FE-SEM observation and diffuse reflectance (DR) UV-Vis spectroscopy. The surface coverage was estimated to be around 50 % for 20 min deposition time. Simple rotation of the excipient powders was found to be one of the effective methods for uniform deposition of nanoparticles.

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

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

    1998-01-01

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

  11. On the behaviour of the spectre of surface waves in a uniform rotating fluid

    This work is devoted to the study of the spectre of surface waves arising in the linear oscillations problem of a portion of an ideal heavy non capillary liquid constrained into a vessel with interior spatial domain U. In the present work we will be concerned with the following two equations: Under which conditions on U and V (volume of liquid enclosed into U) is it possible to assure non existence of discrete spectre of superficial waves in the threshold of the inner wave spectre? How do spectre of superficial waves depend on local variations of angular speed? (author). 5 refs

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

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

    2016-01-13

    The preparation, characterization, and antibacterial testing of Cu-Ag sputtered polyurethane (PU) catheters are addressed in this study. PU catheters with different atomic ratios Cu:Ag have been sputtered and led to different optical properties as followed by diffuse reflectance spectroscopy (DRS) and the surface redox properties were also different for different Cu-Ag ratios as observed by X-ray photoelectron spectroscopy (XPS). The surface atomic percentage concentration of the oxidized/reduced C-species originating from bacterial cultures before and after bacterial inactivation were determined on the Cu-Ag PU catheters. The crystallographic properties were determined by X-ray diffraction (XRD). The XRD-diffractogram showed the presence of Cu2O (111), Cu (200), CuO (020), and Ag (111) indicating that Cu nanoparticles present a more crystalline character compared to Ag nanoparticles. Increasing the percentage of Ag in the Cu-Ag films, bigger Ag-particle agglomerates were detected by scanning transmission electron microscopy (STEM) microanalysis confirming the results obtained by AFM. The bacterial inactivation kinetics of the sputtered Cu-Ag films on PU catheters was investigated in detail. Quasi-instantaneous bacterial inactivation kinetics was induced by the sputtered films on PU catheters after optimization of the Cu-Ag film thickness. PMID:26700113

  13. A Comparative Evaluation of TiO2 Suspension Coating Techniques: A Novel Technique to Achieve Optimal Thickness and Uniformity of Photocatalytic Film

    Abbas Rahimi Foroushani; Parvin Nassiri; Gholamhossein Pourtaghi; Yadollah Mortazavi; Farideh Golbabaei; Masoud Rismanchian

    2012-01-01

    The most important parameters affecting the efficiency of catalysts for the oxidation of the surrounding materials are considered to be the thickness and uniformity of the catalyst layer. The present method for the determination of thickness used in most studies is the analysis of cross-sectional pictures from SEM imaging. This method, however, has several restrictions. This study proposes a feasible and simple method for evaluating the optimal thickness and uniformity using UVA light transmi...

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

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

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

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

    1984-01-01

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

  16. Tilt optimized flip uniformity (TOFU) RF pulse for uniform image contrast at low specific absorption rate levels in combination with a surface breast coil at 7 Tesla

    van Kalleveen, Irene M. L.; Boer, VO; Luijten, Peter R.; Klomp, DWJ

    2015-01-01

    Purpose: Going to ultrahigh field MRI (e. g., 7 Tesla [ T]), the nonuniformity of the B_1 field and the increased radiofrequency (RF) power deposition become challenging. While surface coils improve the power efficiency in B_1, its field remains nonuniform. In this work, an RF pulse was designed tha

  17. 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?").…

  18. Highly efficient industrial large-area black silicon solar cells achieved by surface nanostructured modification

    Li, Ping; Wei, Yi; Zhao, Zengchao; Tan, Xin; Bian, Jiming; Wang, Yuxuan; Lu, Chunxi; Liu, Aimin

    2015-12-01

    Traditional black silicon solar cells show relatively low efficiencies due to the high surface recombination occurring at the front surfaces. In this paper, we present a surface modification process to suppress surface recombination and fabricate highly efficient industrial black silicon solar cells. The Ag-nanoparticle-assisted etching is applied to realize front surface nanostructures on silicon wafers in order to reduce the surface reflectance. Through a further tetramethylammonium hydroxide (TMAH) treatment, the carrier recombination at and near the surface is greatly suppressed, due to a lower surface dopant concentration after the surface modification. This modified surface presents a low reflectivity in a range of 350-1100 nm. Large-area solar cells with an average conversion efficiency of 19.03% are achieved by using the TMAH treatment of 30 s. This efficiency is 0.18% higher than that of standard silicon solar cells with pyramidal surfaces, and also a remarkable improvement compared with black silicon solar cells without TMAH modifications.

  19. 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.

  20. 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

    2016-04-01

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

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

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

    2016-01-01

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

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

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

    2016-06-01

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

  3. Hall effects on magnetohydrodynamic free-convection flow at a stretching surface with a uniform free-stream

    Free convection flow of a conducting fluid near an isothermal sheet with a uniform free stream of constant velocity and temperature is investigated. The sheet is linearly stretched in the presence of a uniform strong transverse magnetic field and the Hall effects are taken into account. The effect of internal heat generation or absorption is also considered. The boundary layer equations governing the problem under consideration have been transformed into a system of ordinary differential equations, which are solved numerically. Velocity and temperature functions are shown on graphs and the numerical values of functions affecting the shear stress and the rate of heat transfer are entered in a table. The effects of the magnetic field, the Hall and the heat source/sink parameters on these functions are discussed. The results are compared with those known from the literature. (orig.)

  4. Uniform superhydrophobic surfaces using micro/nano complex structures formed spontaneously by a simple and cost-effective nonlithographic process based on anodic aluminum oxide technology

    This paper presents a uniform micro/nano double-roughened superhydrophobic surface with a high static contact angle (CA) and low contact angle hysteresis (CAH). The proposed micro/nano complex structured surfaces were self-fabricated simply and efficiently using a very simple and low-cost nonlithographic sequential process, which consists of aluminum (Al) sputtering, anodization of the Al layer and pore widening, without specific equipment and additional subsequent processes. The wetting properties of the fabricated surfaces were characterized by measuring the static CAs and the CAHs after plasma polymerized fluorocarbon coating with a low surface energy. The measured static CA and CAH were 154 ± 2.3° and 5.7 ± 0.8°, respectively, showing that the fabricated double-roughened surfaces exhibit superhydrophobic behaviors clearly. In addition, the proposed double-scaled surfaces at a wafer-level exhibited uniform superhydrophobic behaviors across the wafer with an apparent CA and CAH of 153.9 ± 0.8° and 4.9 ± 1.3°, respectively.

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

    Zheng, Mingtao; Zhang, Haoran; Gong, Xuebin; Xu, Ruchun; Xiao, Yong; Dong, Hanwu; Liu, Xiaotang; Liu, Yingliang

    2013-01-01

    A simple additive-free approach is developed to synthesize uniform manganese monoxide (MnO) one-dimensional nanorods, in which only manganese acetate and ethanol were used as reactants. The as-synthesized MnO nanorods were characterized in detail by X-ray diffraction, scanning and transmission electron microscopy (TEM) including high-resolution TEM and selected-area electron diffraction, Fourier transform infrared spectrum, and nitrogen adsorption isotherm measurements. The results indicate t...

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

    Liu Y

    2015-03-01

    Full Text Available Yang Liu,1,2 Qing Chen,1 Ming Xu,3 Guannan Guan,1 Wen Hu,3 Ying Liang,2 Xiuli Zhao,1 Mingxi Qiao,1 Dawei Chen,1 Hao Liu2 1School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 2Department of Pharmacy, Bengbu Medical College, Bengbu, 3College of Pharmaceutical Science, Soochow University, Suzhou, People’s Republic of China Background: The purpose of this study was to construct hollow mesoporous silica nanoparticles (HMSN decorated with tLyp-1 peptide (tHMSN for dual-targeting drug delivery to tumor cells and angiogenic blood vessel cells.Methods: HMSN were synthesized de novo using a novel cationic surfactant-assisted selective etching strategy and were then modified with tLyp-1. Multiple methods, including transmission electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, bicinchoninic acid assay, and nitrogen adsorption and desorption isotherms, were used to characterize the tHMSN. Doxorubicin were chosen as the model cargo, and the uptake of doxorubicin-loaded tHMSN into MDA-MB-231 cells and human umbilical vein endothelial cells (HUVECs, as models of tumor cells and tumor neovascular endothelial cells, respectively, were observed and detected by confocal laser scanning microscopy and flow cytometry. An in vitro pharmacodynamic study and a study of the mechanism via which the nanoparticles were endocytosed were also performed.Results: HMSN with a highly uniform size and well oriented mesopores were synthesized. After tHMSN were characterized, enhanced uptake of the cargo carried by tHMSN into MDA-MB-231 cells and HUVECs compared with that of their unmodified counterparts was validated by confocal laser scanning microscopy and flow cytometry at the qualitative and quantitative levels, respectively. Further, the pharmacodynamic study suggested that, compared with their unmodified counterparts, doxorubicin-loaded tHMSN had an enhanced inhibitory effect on MDA-MB-231 cells and HUVECs in vitro. Finally, a

  7. Development of a Uniform Theory of Diffraction for Scattered and Surface Electromagnetic Field Analysis on a Cylinder

    García Aguilar, Andrés

    2013-01-01

    Con esta tesis ”Desarrollo de una Teoría Uniforme de la Difracción para el Análisis de los Campos Electromagnéticos Dispersados y Superficiales sobre un Cilindro” hemos iniciado una nueva línea de investigación que trata de responder a la siguiente pregunta: ¿cuál es la impedancia de superficie que describe una estructura de conductor eléctrico perfecto (PEC) convexa recubierta por un material no conductor? Este tipo de estudios tienen interés hoy en día porque ayudan a predecir el campo elec...

  8. Surface accuracy achieved by upsetting of preforms generated by laser rod end melting

    Brüning Heiko

    2015-01-01

    Full Text Available Cold forming generally allows the reproduction of parts with a high production rate and low waste of material. For this reason, many small parts for example of the body of a smartphone undergo at least one forming operation during their fabrication, e.g. screws, brackets or springs. However, when the size of forming products is reduced to the micro range, size effects appear and affect the forming process. One size effect leads to the fact that conventional multi stage upsetting processes cannot be scaled to micro range accordingly. As a consequence, the maximum achievable upset ratio decreases from 2.3 in macro range to values below 2 in micro range. This reduces the efficiency of the upsetting process significantly as more upsetting stages have to be carried out to reach the desired shape of the forming product. A very promising approach to reduce required forming stages is the laser rod end melting process which takes advantage of a size effect. Herein, the lower end of a rod is melted by the energy of a laser beam. The molten part of the rod automatically forms spherical due to surface tension. This droplet-shaped part is called “preform”. After total cooling, the preform is upset within a single stage cold forming operation to achieve the desired shape. In this paper, results of the upsetting operation with regard to surface accuracy of the forming product are presented. It is shown that surface characteristics with dimensions as small as 500 nm can be reasonably reproduced.

  9. 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.

  10. Toward the Limits of Uniformity of Mixed Metallicity SWCNT TFT Arrays with Spark-Synthesized and Surface-Density-Controlled Nanotube Networks.

    Kaskela, Antti; Mustonen, Kimmo; Laiho, Patrik; Ohno, Yutaka; Kauppinen, Esko I

    2015-12-30

    We report the fabrication of thin film transistors (TFTs) from networks of nonbundled single-walled carbon nanotubes with controlled surface densities. Individual nanotubes were synthesized by using a spark generator-based floating catalyst CVD process. High uniformity and the control of SWCNT surface density were realized by mixing of the SWCNT aerosol in a turbulent flow mixer and monitoring the online number concentration with a condensation particle counter at the reactor outlet in real time. The networks consist of predominantly nonbundled SWCNTs with diameters of 1.0-1.3 nm, mean length of 3.97 μm, and metallic to semiconducting tube ratio of 1:2. The ON/OFF ratio and charge carrier mobility of SWCNT TFTs were simultaneously optimized through fabrication of devices with SWCNT surface densities ranging from 0.36 to 1.8 μm(-2) and channel lengths and widths from 5 to 100 μm and from 100 to 500 μm, respectively. The density optimized TFTs exhibited excellent performance figures with charge carrier mobilities up to 100 cm(2) V(-1) s(-1) and ON/OFF current ratios exceeding 1 × 10(6), combined with high uniformity and more than 99% of devices working as theoretically expected. PMID:26666626

  11. Excellent Silicon Surface Passivation Achieved by Industrial Inductively Coupled Plasma Deposited Hydrogenated Intrinsic Amorphous Silicon Suboxide

    Jia Ge

    2014-01-01

    Full Text Available We present an alternative method of depositing a high-quality passivation film for heterojunction silicon wafer solar cells, in this paper. The deposition of hydrogenated intrinsic amorphous silicon suboxide is accomplished by decomposing hydrogen, silane, and carbon dioxide in an industrial remote inductively coupled plasma platform. Through the investigation on CO2 partial pressure and process temperature, excellent surface passivation quality and optical properties are achieved. It is found that the hydrogen content in the film is much higher than what is commonly reported in intrinsic amorphous silicon due to oxygen incorporation. The observed slow depletion of hydrogen with increasing temperature greatly enhances its process window as well. The effective lifetime of symmetrically passivated samples under the optimal condition exceeds 4.7 ms on planar n-type Czochralski silicon wafers with a resistivity of 1 Ωcm, which is equivalent to an effective surface recombination velocity of less than 1.7 cms−1 and an implied open-circuit voltage (Voc of 741 mV. A comparison with several high quality passivation schemes for solar cells reveals that the developed inductively coupled plasma deposited films show excellent passivation quality. The excellent optical property and resistance to degradation make it an excellent substitute for industrial heterojunction silicon solar cell production.

  12. 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.

  13. 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; Shibahashi, Hiromoto; Murphy, Simon J.; Sekii, Takashi; Bedding, Timothy R.

    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 hyd...

  14. Radiation heat transfer model using Monte Carlo ray tracing method on hierarchical ortho-Cartesian meshes and non-uniform rational basis spline surfaces for description of boundaries

    Kuczyński Paweł

    2014-06-01

    Full Text Available The paper deals with a solution of radiation heat transfer problems in enclosures filled with nonparticipating medium using ray tracing on hierarchical ortho-Cartesian meshes. The idea behind the approach is that radiative heat transfer problems can be solved on much coarser grids than their counterparts from computational fluid dynamics (CFD. The resulting code is designed as an add-on to OpenFOAM, an open-source CFD program. Ortho-Cartesian mesh involving boundary elements is created based upon CFD mesh. Parametric non-uniform rational basis spline (NURBS surfaces are used to define boundaries of the enclosure, allowing for dealing with domains of complex shapes. Algorithm for determining random, uniformly distributed locations of rays leaving NURBS surfaces is described. The paper presents results of test cases assuming gray diffusive walls. In the current version of the model the radiation is not absorbed within gases. However, the ultimate aim of the work is to upgrade the functionality of the model, to problems in absorbing, emitting and scattering medium projecting iteratively the results of radiative analysis on CFD mesh and CFD solution on radiative mesh.

  15. 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

  16. 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. PMID:25444660

  17. 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)

  18. 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.

  19. On uniform topological algebras

    Azhari, M. El

    2013-01-01

    The uniform norm on a uniform normed Q-algebra is the only uniform Q-algebra norm on it. The uniform norm on a regular uniform normed Q-algebra with unit is the only uniform norm on it. Let A be a uniform topological algebra whose spectrum M (A) is equicontinuous, then A is a uniform normed algebra. Let A be a regular semisimple commutative Banach algebra, then every algebra norm on A is a Q-algebra norm on A.

  20. Computation of ion implantation uniformity

    Commercial ion implanters employ a variety of different systems to scan the ion beam over the target. In many of the target scanning systems employed the achievable uniformity of dose has been limited by the chosen geometry. This paper describes a computer program which has been used to calculate the dose uniformity of a number of these systems. The results are presented as iso-dose lines relative to the dose at the centre of the target. The non-uniformities are then directly apparent and the parameters controlling their magnitude can be readily considered by equipment designers, purchasers or users. (author)

  1. Modelling specific adsorption of divalent metals on montmorillonite surfaces. Pitfalls, recent achievements and current challenges

    Document available in extended abstract form only. In the framework of clay barrier concept for underground nuclear waste storage, montmorillonite and bentonite have been widely used as reference materials for sorption. Recently, accompanying modelling work aims at understanding and predicting sorption in more complex systems where clay are assumed to be representative of the most reactive natural phases. This 'bottom-up' approach relies on a good confidence in the mechanistic understanding of sorption phenomena. The present study aims at reviewing clay sorption experimental and modelling works with a focus on divalent metals surface complexation mechanisms. Clay sorption processes together with current modelling concepts will be discussed. Based on this current knowledge, criteria will be set up to select data that are relevant for surface complexation model calibration (especially ionic strength, pH, clay preparation, metal to clay ratio and solubility limits). We identified missing information, which is necessary to model sorption data in a mechanistic way, together with experimental features that cast doubt on the ability of surface complexation models to catch adequately the nature of divalent metal sorption on montmorillonite edge surface. Problematic experimental features will be highlighted, especially those related to the reversibility of sorption (surface complexation model approaches make the hypothesis of total reversibility) and the effect of solid to liquid ratio (RSL) on sorption distribution coefficients (thermodynamic equilibrium condition agrees only with a constant distribution coefficient as a function of RSL). Neglecting these possible problems, models available in the literature will be then tested in terms of efficiency (data fit) and mechanistic likelihood. Although the link between edge surface charge and edge surface potential is complicated by the spill-over of electrostatic field present on basal and interlayer surfaces on edge surfaces

  2. Diamond-turning HP-21 beryllium to achieve an optical surface

    Investigation of diamond turning on beryllium was made in anticipation of obtaining an optical finish. Although results of past experiences were poor, it was decided to continue diamond turning on beryllium beyond initial failures. By changing speed and using coolant, partial success was achieved. Tool wear was the major problem. Tests were made to establish and plot wear as a function of cutting speed and time. Slower speeds did cause lower wear rates, but at no time did wear reach an acceptable level. The machine, tools, and procedure used were chosen based on the results of preliminary attempts and on previous experience. It was unnecessary to use an air-bearing spindle because tool failure governed the best finish that could be expected. All tools of diamond composition, whether single crystal or polycrystalline, wore at unacceptable rates. Based on present technology, it must be concluded that beryllium cannot be feasibly diamond turned to achieve an optical finish. (22 fig.)

  3. Approximate Solutions of a Higher Order MHD Flow of a Uniformly Stretched Vertical Permeable Surface in the Presence of Heat Generation/Absorption which Resulted from a Quadratic Reaction

    O. K. Koriko

    2010-01-01

    Full Text Available Higher order MHD flow of a uniformity stretched vertical permeable surface in the presence of heat generation/absorption which resulted from a quadratic reaction was studied. The resulting coupled nonlinear partial differential equations is solved by asymptotic expansion. It was discovered that the maximum value of velocity occurs in the body of the fluid close to the surface not at the surface. The effect of heat generated on the velocity profile is more pronounced than that of heat absorption.

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

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

    2011-11-01

    Pulp mill wastewater was treated using the coagulation-flocculation process with aluminum chloride as the coagulant and a modified natural polymer, starch-g-PAM-g-PDMC [polyacrylamide and poly (2-methacryloyloxyethyl) trimethyl ammonium chloride], as the flocculant. A novel approach with a combination of response surface methodology (RSM) and uniform design (UD) was employed to evaluate the effects and interactions of three main influential factors, coagulant dosage, flocculant dosage and pH, on the treatment efficiency in terms of the supernatant turbidity and lignin removals as well as the water recovery. The optimal conditions obtained from the compromise of the three desirable responses, supernatant turbidity removal, lignin removal and water recovery efficiency, were as follows: coagulant dosage of 871 mg/L, flocculant dosage of 22.3 mg/L and pH 8.35. Confirmation experiments demonstrated that such a combination of the UD and RSM is a powerful and useful approach for optimizing the coagulation-flocculation process for the pulp mill wastewater treatment. PMID:21920576

  5. Achievable Efficiency of Numerical Methods for Simulations of Solar Surface Convection

    Grimm-Strele, Hannes; Muthsam, Herbert J

    2014-01-01

    We investigate the achievable efficiency of both the time and the space discretisation methods used in Antares. We show that the fifth order variant of WENO combined with a second order Runge-Kutta scheme is not only more accurate than standard first and second order schemes, but also more efficient taking the computation time into account. Then, we calculate the error decay rates of WENO with several explicit Runge-Kutta schemes for advective and diffusive problems with smooth and non-smooth initial conditions. With this data, we estimate the computational costs of three-dimensional simulations and show that SSP RK(3,2) is the most efficient scheme considered in this comparison.

  6. 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.

  7. The effect of inducing uniform Cu growth on formation of electroless Cu seed layer

    Lim, Taeho; Kim, Myung Jun; Park, Kyung Ju; Kim, Kwang Hwan; Choe, Seunghoe [School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 151-742 (Korea, Republic of); Lee, Young-Soo [Department of Environmental Engineering, Kwangwoon University, Nowon-gu, Seoul 139–701 (Korea, Republic of); Kim, Jae Jeong, E-mail: jjkimm@snu.ac.kr [School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul 151-742 (Korea, Republic of)

    2014-08-01

    The uniformity of Cu growth on Pd nanocatalysts was controlled by using organic additives in the formation of electroless Cu seed layers. Polyethylene glycol (PEG, Mw. 8000) not only reduced the deposition rate but also improved the uniformity of Cu growth on each Pd nanocatalyst during the seed layer formation. The stronger suppression effect of PEG on Cu than on Pd reduced the difference in the deposition rate between the two surfaces, resulting in the uniform deposition. Meanwhile, bis(3-sulfopropyl) disulfide degraded the uniformity by strong and nonselective suppression. The sheet resistance measurement and atomic force microscopy imaging revealed that the uniform Cu growth by PEG was more advantageous for the formation of a thin and smooth Cu seed layer than the non-uniform growth. The uniform Cu growth also had a positive influence on the subsequent Cu electrodeposition: the 60-nm-thick electrodeposited Cu film on the Cu seed layer showed low resistivity (2.70 μΩ·cm), low surface roughness (6.98 nm), and good adhesion strength. - Highlights: • Uniform Cu growth on Pd was achieved in formation of electroless Cu seed layer. • PEG addition to electroless bath improved the uniformity of Cu growth on Pd. • A thin, smooth and continuous Cu seed layer was obtained with PEG. • Adhesion strength of the Cu seed layer was also improved with PEG. • The uniformity improvement positively affected subsequent Cu electrodeposition.

  8. A comparative study on different surface decontaminants on chevon carcass quality to achieve product safety

    Full text: Goat meat (chevon) is the costliest meat in Indian sub-continent due to its widen acceptance amongst the consumers. Behind this acceptance, its virtue over other meats, mainly because it is devoid of any religious restrictions is considered as one of the important factors to endow with nutrition to the human population. Indian sub-continent is having the highest number of goat 124.36 Million and about 36 percent of this population is slaughtered annually. Consumers demand safe and hygienic meat and it is the onus of the technocrats or the scientists to provide guarantee in this regard. It has been reported by a number of researchers that a major part of food borne interic infections could be transferred from the body of the animal to the meat. To avoid this situation a several technique of surface decontamination have been tried with varying degrees of success. Out of these, the chlorinated water was found to be effective and easy method; but, in course of time, its bleaching effect, preparation of its standardized solution and transfer of its certain odour to the carcass and subsequent to the meat put this technique on a question mark and obligated the scientist to take up this aspect of work for further analyses. With all these in perspectives and also to identify a simple, convenient to adopt, cheap and ecofriendly with hazardous left over effect and in consistent with the existing legislature, this work was outlined, where hot water (80 deg C), lactic acid, chlorine solution and acidified sodium chlorite solutions were used as surface decontaminants on chevon carcass. The work was designed to have a comparative study on the effect of different surface decontaminants, namely, hot water (80 deg C for 2 minutes), 2% lactic acid for 30 seconds, 1200 ppm acidified sodium chlorite (ASC) for 5 seconds and 50 ppm chlorine solution for 5 minutes in a form of dip and spray on the surface of dressed chevon carcass for 0, 24, 48 and 72 hours of storage. The

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

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

    2015-01-01

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

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

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

    2015-12-30

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

  11. Uniformity of a dielectric barrier glow discharge: experiments and two-dimensional modeling

    The experimental and calculated results of uniformity in a glow dielectric barrier discharge (DBD) under sub-atmospheric pressures are reported. Driven by a square-wave power source, the discharge in a parallel-electrode DBD system shows uniform or various lateral structures under different conditions. There exists a critical frequency below which the DBD is uniform for almost all the applied voltages. Above the critical frequency, a non-uniform (patterned) discharge is observed and the patterned structures change with frequency and voltage. A two-dimensional fluid modeling is performed on this DBD system which shows similar results in agreement with the experiments. The simulations reveal that the distribution of the space electron density at the beginning of each voltage pulse plays an important role in achieving the uniformity. Uniform space charge results in a uniform DBD. The patterned DBD always evolves from the initial uniform state to the eventual non-uniform one. During this process, the space electrons form a patterned distribution ahead of the surface charges and lead to non-uniform discharge channels.

  12. 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)

  13. 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…

  14. Mandatory School Uniforms.

    Cohn, Carl A.

    1996-01-01

    Shortly after implementing a mandatory school uniform policy, the Long Beach (California) Public Schools can boast 99% compliance and a substantial reduction in school crime. The uniforms can't be confused with gang colors, save parents money, and help identify outsiders. A sidebar lists ingredients for a mandatory uniform policy. (MLH)

  15. 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.

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

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

    2015-01-01

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

  17. 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…

  18. Uniform Practical Nonlinear Output Regulation

    Marconi, Lorenzo; Praly, Laurent

    2008-01-01

    International audience In this paper, we present a solution to the problem of asymptotic and practical semiglobal regulation by output feedback for nonlinear systems. A key feature of the proposed approach is that practical regulation is achieved uniformly with respect to the dimension of the internal model and to the gain of the stabilizer near the zero error manifold. This property renders the approach interesting for a number of real cases by bridging the gap between output regulation t...

  19. 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.

  20. 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

  1. Improving the electrochemical properties of Li1.2Mn0.52Co0.08Ni0.2O2 cathode material by uniform surface nanocoating with samarium fluoride through depositional-hydrothermal route

    Graphical abstract: Li1.2Mn0.52Co0.08Ni0.2O2 cathode material uniformly nanocoated with samarium fluoride (SmF3) has been successfully synthesized through a chemical deposition method followed by low-temperature hydrothermal treatment. The surface modified cathode shows a significantly improved cycling stability and rate capability. - Highlights: • Samarium fluoride is originally used as coating material of Li-rich layered cathode. • Low-temperature hydrothermal treatment is employed to establish uniform surface coating. • Cathode nanocoated with SmF3 shows improved rate capability and cycling stability. • Coating material suppresses the side reaction between electrode and electrolyte. - Abstract: Surface nanocoating of lithium-rich layered Li1.2Mn0.52Co0.08Ni0.2O2 with samarium fluoride (SmF3) has been performed through a chemical deposition route combined with a low-temperature hydrothermal treatment. The surface-modified Li1.2Mn0.52Co0.08Ni0.2O2 particles are uniformly and completely covered by an amorphous SmF3 protective layer with a thin thickness of ∼20 nm. After surface modification, the coated Li1.2Mn0.52Co0.08Ni0.2O2 as cathode shows a significantly improved cycling stability, keeping a capacity retention of 84.5% after 150 cycles at 2 C, much higher than 68.9%forits uncoated counterpart. Moreover, the coated sample delivers an enhanced rate capability with an average capacity of ∼132.3 mA h g−1 when charged at 5 C and discharged at 0.2 C, while the uncoated counterpart only exhibits a capacity of ∼111.4 mA h g−1 under the same conditions. Our results reveal that the remarkably improved electrochemical performance of the surface-modified cathode is attributed to the presence of uniform, robust, and nanoscale SmF3 coating layer, which not only suppresses the growth of SEI layer by reducing the side reaction between cathode and electrolyte solution, but also strengthens the structure stability of the Li-rich layered cathode materials

  2. Research of Surface Temperature Uniformity of Pumping and Airblast Style U-Type Radiant Tube%抽-鼓式U型辐射管表面温度均匀性研究

    张少强; 徐少春; 沈小军; 高阳; 伍成波

    2011-01-01

    The performance of pumping and airblast style U-type radiant tube heating unit was studied,and the temperature uniformity of the radiant tube surface and the factors affecting the temperature distribution were studied mainly. It was found that the temperature uniformity of the radiant tube surface could be regulated accessorially by regulating the quantity of the primary air and the second air, when the structure of burner was definite. With the rise of the preheated air temperature and the temperature in the heating furnace, the temperature uniformity of radiant tube surface also could be improved. Whereas the effect of the zero pressure location was not obvious to the temperature distribution of the radiant tube surface.%对抽-鼓式U型辐射管加热装置进行了研究,主要研究了辐射管表面温度的均匀性及其影响因素.实验研究表明:当燃烧器结构一定时,调节一、二次进风量的配比,可辅助性的调节辐射管表面温度的均匀性.随着空气预热温度及炉膛温度的升高,同样能改善辐射管表面温度的均匀性.而辐射管内零压面的位置对辐射管表面温度分布的影响很小.

  3. 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.

  4. Proposal of use of diesel engine and surface-piercing propeller to achieve fuel savings for inshore fishing boats

    Zainol, Ismail; Yaakob, Omar

    2016-02-01

    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.

  5. 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. PMID:25073123

  6. 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.

  7. 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.

  8. Uniformity of aluminium foils

    Commercially produced rolled and beaten Al foils and evaporated Al foils have been examined for thickness uniformity with an areal resolution of about 5 x 10-6 cm2 by measurements of proton backscattering yield using the Harwell microbeam facility. The evaporated Al foils were found to be uniform to better than 1% but the rolled foils were found to have non-uniformities of as much as 5-10% of their mean thickness. This is sufficient to contribute significantly to systematic errors in measurement of fast heavy ion energy straggling. (Auth.)

  9. Non-uniform reductions

    Buhrman, H.; Hescott, B.; Homer, S.; Torenvliet, L.

    2010-01-01

    We study properties of non-uniform reductions and related completeness notions. We strengthen several results of Hitchcock and Pavan (ICALP (1), Lecture Notes in Computer Science, vol. 4051, pp. 465-476, Springer, 2006) and give a trade-off between the amount of advice needed for a reduction and its honesty on NEXP. We construct an oracle relative to which this trade-off is optimal. We show, in a more systematic study of non-uniform reductions, among other things that non-uniformity can be re...

  10. 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.

  11. 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.

  12. Highly Uniform Epitaxial ZnO Nanorod Arrays for Nanopiezotronics

    Nagata T

    2009-01-01

    Full Text Available Abstract Highly uniform and c-axis-aligned ZnO nanorod arrays were fabricated in predefined patterns by a low temperature homoepitaxial aqueous chemical method. The nucleation seed patterns were realized in polymer and in metal thin films, resulting in, all-ZnO and bottom-contacted structures, respectively. Both of them show excellent geometrical uniformity: the cross-sectional uniformity according to the scanning electron micrographs across the array is lower than 2%. The diameter of the hexagonal prism-shaped nanorods can be set in the range of 90–170 nm while their typical length achievable is 0.5–2.3 μm. The effect of the surface polarity was also examined, however, no significant difference was found between the arrays grown on Zn-terminated and on O-terminated face of the ZnO single crystal. The transmission electron microscopy observation revealed the single crystalline nature of the nanorods. The current–voltage characteristics taken on an individual nanorod contacted by a Au-coated atomic force microscope tip reflected Schottky-type behavior. The geometrical uniformity, the designable pattern, and the electrical properties make the presented nanorod arrays ideal candidates to be used in ZnO-based DC nanogenerator and in next-generation integrated piezoelectric nano-electromechanical systems (NEMS.

  13. Total Skin Electron Irradiation: Evaluation of Dose Uniformity

    Total Skin Electron Beam Irradiation (TSEI) is one of the most sophisticated treatment techniques of modern radiation oncology practice. TSEI is used in cutaneous T-cell lymphoma, mycosis fungoides (MF), and Kaposi sarcoma. The objective of TSEI is to uniformly deliver a specified dose over the entire skin surface down to a particular depth. However, considerable technical and dosimetric difficulties exist in achieving this goal due to patient and treatment machine factors. Thermoluminescent dosimetry (TLD) measurements are usually performed to evaluate dose distribution throughout the body. This paper presents the in vivo dosimetric data of 67 treatments on 58 patients with MF, treated with TSEI

  14. 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.

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

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

  16. Uniform and Robust Peptoid Microsphere Coatings

    Servoss, Shannon L.; Phillip Blake; Melissa L. Hebert; Dhaval S. Shah

    2013-01-01

    Peptoids that are helical and partially water soluble have been shown to self-assemble into microspheres when the peptoid solution is dried on a silicon substrate. Such microsphere coatings have great potential for use in biosensor technologies, specifically to increase the surface area for binding. However, in order to be useful, the peptoids must consistently form uniform coatings. In this study we investigated the effects of various coating protocol parameters on the uniformity of the resu...

  17. Three-dimensional noble-metal nanostructure: A new kind of substrate for sensitive, uniform, and reproducible surface-enhanced Raman scattering

    Surface-enhanced Raman spectroscopy (SERS) is a powerful vibrational spectroscopy technique for highly sensitive structural detection of low concentration analyte. The SERS activities largely depend on the topography of the substrate. In this review, we summarize the recent progress in SERS substrate, especially focusing on the three-dimensional (3D) noble-metal substrate with hierarchical nanostructure. Firstly, we introduce the background and general mechanism of 3D hierarchical SERS nanostructures. Then, a systematic overview on the fabrication, growth mechanism, and SERS property of various noble-metal substrates with 3D hierarchical nanostructures is presented. Finally, the applications of 3D hierarchical nanostructures as SERS substrates in many fields are discussed. (invited review — international conference on nanoscience and technology, china 2013)

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

    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−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 (Vs/Vv) 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

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

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

    2016-04-01

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

  20. Catalyst free growth of high density uniform InN nanocolumns on p-GaAs(0 0 1) surface by PA-MBE and their in situ XPS analysis

    Highlights: • High density uniform InN nanocolumns were obtained on p-GaAs(0 0 1) substrate. • Indium beam irradiation method had improved the crystal quality largely. • Stoichiometric ratio of all InN samples was close to 1:1 gotten by in situ XPS spectra. - Abstract: Through Indium beam irradiation toward the substrate before growing, high density uniform InN nanocolumns were obtained on p-GaAs(0 0 1) substrate and their possible one dimensional (1D) growth mechanism was analyzed. Rocking curves of all samples showed that Indium beam irradiation method had improved the crystal quality largely, which might be an effective way to release the strain between hexagonal InN(0 0 0 1) and cubic GaAs(0 0 1) with large lattice mismatch. Through quantitative analysis of XPS spectra gotten by in situ measurement, it was found that the InN stoichiometric ratio of all three samples were close to 1:1, which revealed that there was no residual metal at the tip of our nanocolumns. No catalyst or residual metal left could keep its electronic and optical property intact. All three samples showed strong photoluminescence at room temperature. To effectively release the strain and get well surface and interface are important for heterojunction optoelectronic device based on InN

  1. Effects of Radiation and Heat Generation/Absorption on MHD Free Convective Heat Transfer of Power-Law Non-Newtonian Fluids Along a Power-Law Stretching Sheet with Uniform Surface Heat Flux

    M.A. Samad

    2013-01-01

    Full Text Available An analysis is carried out to investigate the effects of MHD free convection heat transfer of power-law non-Newtonian fluids along a stretching sheet. This has been done under the simultaneous action of suction, heat generation/absorption, thermal radiation and uniform transverse magnetic field. The stretching sheet is assumed to continuously moving with a power-law velocity and maintaining a uniform surface heat flux. The governing nonlinear partial differential equations are transformed into a system of nonlinear ordinary differential equations using appropriate similarity transformations. The resulting non-linear equations are solved numerically using Nachtsheim-Swigert shooting iterative technique along with sixth order Runge-Kutta integration scheme. Numerical results for the non-dimensional velocity and temperature profiles are shown graphically and discussed. The effects of skin-friction coefficient and the local Nusselt number which are of physical and engineering interest are studied and presented graphically as well as in the form of tables for the variation of different physically important parameters. A comparison of the present study is also performed with the previously published study and found excellent agreement.

  2. Catalyst free growth of high density uniform InN nanocolumns on p-GaAs(0 0 1) surface by PA-MBE and their in situ XPS analysis

    Jing, Qiang; Yang, Hang; Li, Wancheng, E-mail: liwc@jlu.edu.cn; Wu, Guoguang, E-mail: wugg@jlu.edu.cn; Zhang, Yuantao; Gao, Fubin; Zhao, Yang; Du, Guotong

    2015-03-15

    Highlights: • High density uniform InN nanocolumns were obtained on p-GaAs(0 0 1) substrate. • Indium beam irradiation method had improved the crystal quality largely. • Stoichiometric ratio of all InN samples was close to 1:1 gotten by in situ XPS spectra. - Abstract: Through Indium beam irradiation toward the substrate before growing, high density uniform InN nanocolumns were obtained on p-GaAs(0 0 1) substrate and their possible one dimensional (1D) growth mechanism was analyzed. Rocking curves of all samples showed that Indium beam irradiation method had improved the crystal quality largely, which might be an effective way to release the strain between hexagonal InN(0 0 0 1) and cubic GaAs(0 0 1) with large lattice mismatch. Through quantitative analysis of XPS spectra gotten by in situ measurement, it was found that the InN stoichiometric ratio of all three samples were close to 1:1, which revealed that there was no residual metal at the tip of our nanocolumns. No catalyst or residual metal left could keep its electronic and optical property intact. All three samples showed strong photoluminescence at room temperature. To effectively release the strain and get well surface and interface are important for heterojunction optoelectronic device based on InN.

  3. 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...

  4. Bivariate Uniform Deconvolution

    Benešová, Martina; van Es, Bert; Tegelaar, Peter

    2011-01-01

    We construct a density estimator in the bivariate uniform deconvolution model. For this model we derive four inversion formulas to express the bivariate density that we want to estimate in terms of the bivariate density of the observations. By substituting a kernel density estimator of the density of the observations we then get four different estimators. Next we construct an asymptotically optimal convex combination of these four estimators. Expansions for the bias, variance, as well as asym...

  5. Women in service uniforms

    Hanna Karaszewska; Maciej Muskała

    2012-01-01

    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 th...

  6. Uniform random spanning trees

    Pemantle, Robin

    2004-01-01

    There are several good reasons you might want to read about uniform spanning trees, one being that spanning trees are useful combinatorial objects. Not only are they fundamental in algebraic graph theory and combinatorial geometry, but they predate both of these subjects, having been used by Kirchoff in the study of resistor networks. This article addresses the question about spanning trees most natural to anyone in probability theory, namely what does a typical spanning tree look like?

  7. Uniformly hyperbolic control theory

    Kawan, Christoph

    2015-01-01

    This paper gives a summary of a body of work at the intersection of control theory and smooth nonlinear dynamics. The main idea is to transfer the concept of uniform hyperbolicity, central to the theory of smooth dynamical systems, to control-affine systems. Combining the strength of geometric control theory and the hyperbolic theory of dynamical systems, it is possible to deduce control-theoretic results of non-local nature that reveal remarkable analogies to the classical hyperbolic theory ...

  8. Uniform and reproducible stirring in a microbioreactor

    Bolic, Andrijana; Eliasson Lantz, Anna; Rottwitt, Karsten;

    role in achieving successful cultivations by promoting uniform process conditions and – for aerobic cultivations – a high oxygen transfer rate. In this contribution, the development of a suitable, reliable and reproducible stirrer in a microbioreactor for batch and continuous cultivation of S...

  9. 23 CFR 655.604 - Achieving basic uniformity.

    2010-04-01

    ... Highways FEDERAL HIGHWAY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION ENGINEERING AND TRAFFIC OPERATIONS TRAFFIC OPERATIONS Traffic Control Devices on Federal-Aid and Other Streets and Highways § 655.604... traffic control devices or the installation of needed traffic control devices on or off the...

  10. Improved electrochemical stability at the surface of La(0.8)Sr(0.2)CoO3 achieved by surface chemical modification.

    Tsvetkov, Nikolai; Lu, Qiyang; Yildiz, Bilge

    2015-01-01

    The degradation of the surface chemistry on perovskite (ABO3) oxides is a critical issue for their performance in energy conversion systems such as solid oxide fuel/electrolysis cells and in splitting of H2O and CO2 to produce fuels. This degradation is typically in the form of segregation and phase separation of dopant cations from the A-site, driven by elastic and electrostatic energy minimization and kinetic demixing. In this study, deposition of Ti at the surface was found to hinder the dopant segregation and the corresponding electrochemical degradation on a promising SOFC cathode material, La(0.8)Sr(0.2)CoO3 (LSC). The surface of the LSC films was modified by Ti (denoted as LSC-T) deposited from a TiCl4 solution. The LSC and LSC-T thin films were investigated by electrochemical impedance spectroscopy, nano-probe Auger electron spectroscopy, and X-ray photoelectron spectroscopy (XPS), upon annealing at 420-530 °C in air up to about 90 hours. The oxygen exchange coefficient, k(q), on LSC-T cathodes was found to be up to 8 times higher than that on LSC cathodes at 530 °C and retained its stability. Sr-rich insulating particles formed at the surface of the annealed LSC and LSC-T films, but with significantly less coverage of such particles on the LSC-T. From this result, it appears that modification of the LSC surface with Ti reduces the segregation of the blocking Sr-rich particles at the surface, and a larger area on LSC surface (with a higher Sr doping level in the lattice) is available for the oxygen reduction reaction. The stabilization of the LSC surface through Ti-deposition can open a new route for designing surface modifications on perovskite oxide electrodes for high temperature electro- and thermo-chemical applications. PMID:26227310

  11. 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.

  12. Design and performance of high uniformity linear filament electron gun

    Iqbal, Munawar; Fazal-e-Aleem

    2006-10-01

    We describe new features and results from the previously reported [M. Iqbal et al., Rev. Sci. Instrum. 74, 4616 (2003)] thermionic long (up to 140mm) cathode, electromagnetically focused electron beam gun. The gun which was tested up to 50kW (5000mA×10kV) achieves power density of 33kW/cm2 at the target. The cathode temperature and emission current was uniform over a length of 100mm of the cathode. The beam density profile along the line cathode strongly relates to the temperature distribution along the line cathode. The gun has a remarkable application in heat treatment of large surface area and to coat large substrate surfaces at much faster evaporation rates with lower cost.

  13. Elimination of Quench Cracking by Controlling Agitation Uniformity

    CANALE, Lauralice C.F; TOTTEN, George E

    2004-01-01

    Uniform agitation of the quenchant is a critically important control parameter in optimizing distortion control and reducing steel cracking. Quenching with ultrasonic agitation or in the presence of electrical and magnetic fields provide uniform agitation leading to improved uniformity of the stress fields within the metal not readily achievable with more traditional agitation methods such as propeller pumps and sprays. These methods provide the additional potential advantage of varying agitation throughout the cooling cycle to achieve a wide range of cooling profiles not readily achievable with quenchants and more traditional agitation systems currently in use.

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

    Lin, Chin-An; Tsai, Meng-Lin; Wei, Wan-Rou; Lai, Kun-Yu; He, Jr-Hau

    2016-01-26

    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. PMID:26623934

  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. Thin films' thickness uniformity associated with the method of electron beam evaporation

    Xia, Zhilin; Xue, Yiyu; Guo, Peitao; Li, Zhangwang

    2009-08-01

    Coating material has been considered as being made up of a lot of small tablets. These tablets have plane surface during the whole film preparation process. Based on the assumption that a column etching pit will form in coating material when electron beam is used for heating, influences of the etching pit's dimension and the internal structure of the vacuum chamber on films thickness uniformity have been investigated. Results reflect that the appearance of etching pit does not always cause negative influence on films thickness uniformity. The negative impact of etching on films thickness uniformity can be reduced by optimizing the internal structure of the vacuum chamber and preparation technical parameters. But, it is difficult to achieve the beneficial action. This investigation is useful to help us understand physical meaning of the emission characteristics of the evaporation particle and design experimental scheme.

  17. 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...

  18. Achieving highly effective non-biofouling performance for polypropylene membranes modified by UV-induced surface graft polymerization of two oppositely charged monomers.

    Zhao, Yong-Hong; Zhu, Xiao-Ying; Wee, Kin-Ho; Bai, Renbi

    2010-02-25

    A major problem in membrane technology for applications such as wastewater treatment or desalination is often the loss of membrane permeability due to biofouling initiated from protein adsorption and biofilm formation on the membrane surface. In this study, we developed a relatively simple and yet versatile approach to prepare polypropylene (PP) membrane with highly effective non-biofouling performance. Copolymer brushes were grafted to the surface of PP membrane through UV-induced polymerization of two oppositely charged monomers, i.e., [2-(methacryloyloxy)ethyl]trimethylammonium chloride (TM) and 3-sulfopropyl methacrylate potassium salt (SA), with varying TM:SA molar ratios. Surface analysis with scanning electron microscope (SEM) clearly showed the grafted copolymer brushes on the membrane surfaces and that with X-ray photoelectron spectroscope (XPS) revealed a similar TM:SA ratio of the grafted copolymer brushes to that of the monomer solution used for the polymerization. Water contact angle measurements indicated that the hydrophilicity of the membrane surfaces was remarkably improved by the grafting of the TM/SA copolymer brushes, with the lowest water contact angle of 27 degrees being achieved at the TM:SA ratio of around 1:1. Experiments for antiprotein adsorption with bovine serum album (BSA) and lysozyme (LYZ) and antibiofilm formation with Escherichia coli (E. coli) demonstrated a great dependence of the membrane performance on the TM:SA ratios of the grafted copolymer brushes. It was found that the characteristics of the surface charges of the membrane surfaces played a very important role in the non-biofouling performance, and the membrane surface with balanced positive and negative charges showed the best non-biofouling performance for the proteins and bacteria tested in this study. PMID:20121056

  19. 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…

  20. The Influence of a Mandatory School Uniform Policy.

    Pate, Sharon Shamburger

    This essay examines the influence of a mandatory school-uniform dress code on academic achievement and discipline infractions. In addition, student gender and type of school district were compared to show the influence of this policy. Only schools that implemented a mandatory school-uniform policy in 1996 and had data for discipline infractions…

  1. 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.

  2. Skin carcinogenesis following uniform and non-uniform β irradiation

    Where workers or the general public may be exposed to ionising radiation, the irradiation is rarely uniform. The risk figures and dose limits recommended by the International Commission on Radiological Protection (ICRP) are based largely on clinical and epidemiological studies of reasonably uniform irradiated organs. The paucity of clinical or experimental data for highly non-uniform exposures has prevented the ICRP from providing adequate recommendations. This weakness has led on a number of occasions to the postulate that highly non-uniform exposures of organs could be 100,000 times more carcinogenic than ICRP risk figures would predict. This so-called ''hot-particle hypothesis'' found little support among reputable radiobiologists, but could not be clearly and definitively refuted on the basis of experiment. An experiment, based on skin tumour induction in mouse skin, is described which was developed to test the hypothesis. The skin of 1200 SAS/4 male mice has been exposed to a range of uniform and non-uniform sources of the β emitter 170Tm (Emax ∼ 1 MeV). Non-uniform exposures were produced using arrays of 32 or 8 2-mm diameter sources distributed over the same 8-cm2 area as a uniform control source. Average skin doses varied from 2-100 Gy. The results for the non-uniform sources show a 30% reduction in tumour incidence by the 32-point array at the lower mean doses compared with the response from uniform sources. The eight-point array showed an order-of-magnitude reduction in tumour incidence compared to uniform irradiation at low doses. These results, in direct contradiction to the ''hot particle hypothesis'', indicate that non-uniform exposures produce significantly fewer tumours than uniform exposures. (author)

  3. Extensional Uniformity for Boolean Circuits

    McKenzie, Pierre; Vollmer, Heribert

    2008-01-01

    Imposing an extensional uniformity condition on a non-uniform circuit complexity class C means simply intersecting C with a uniform class L. By contrast, the usual intensional uniformity conditions require that a resource-bounded machine be able to exhibit the circuits in the circuit family defining C. We say that (C,L) has the "Uniformity Duality Property" if the extensionally uniform class C \\cap L can be captured intensionally by means of adding so-called "L-numerical predicates" to the first-order descriptive complexity apparatus describing the connection language of the circuit family defining C. This paper exhibits positive instances and negative instances of the Uniformity Duality Property.

  4. UCT IN UNIFORM

    D.C. Robertson

    2012-02-01

    Full Text Available 1979 saw the celebration of the 150th anniversary of the founding of an educational establishment in the Cape which was to develop into the University of Cape Town. To mark this anniversary the authors have presented a short history of UCT in uniform, highlighting the multifarious contributions made by UCTstudents and staff. This documented history clearly indicates the valuable contribution that not only UCT but all South African universities and their members have made in the past and will be called to make in the future. Changes in national service policy particularly with regard to urban commandos have resulted in the replacement of the UCT Regiment by the Cape Garrison Artillery. However, the loss of the UCT Regiment itself, certainly does not point to the end of UCT's contribution to the defence of South Africa. For at this very moment, in diverse regiments throughout South Africa, members of the UCT community are making a valiant contribution in answering the call of their country.

  5. Uniform Reduction to SAT

    Janicic, Predrag

    2010-01-01

    There is a huge number of problems, from various areas, being solved by reducing them to SAT. However, for most applications, translations into SAT are performed by specialized, problem-specific tools. In this paper we describe a novel approach for uniform solving of a wide class of problems by reducing them to SAT. The approach uses a new specification language that combines imperative and declarative programming paradigms. A problem is specified by a test (expressed in an imperative form) that a given set of values indeed makes a solution to the problem. In the solving phase, parameters of the problem are represented by (finite) vectors of propositional formulae and the specification is symbolically executed. An assertion that given values make a solution is transformed to an instance of the SAT problem and passed to a SAT solver. If the formula is satisfiable, its model is transformed back to variables describing the problem, i.e., to a solution of the problem. We also describe a system URSA that implement...

  6. Uniform and Robust Peptoid Microsphere Coatings

    Shannon L. Servoss

    2013-06-01

    Full Text Available Peptoids that are helical and partially water soluble have been shown to self-assemble into microspheres when the peptoid solution is dried on a silicon substrate. Such microsphere coatings have great potential for use in biosensor technologies, specifically to increase the surface area for binding. However, in order to be useful, the peptoids must consistently form uniform coatings. In this study we investigated the effects of various coating protocol parameters on the uniformity of the resulting peptoid microsphere coatings, including (i solvent, (ii administration technique, and (iii drying environment. In addition, we investigated the robustness of the coatings as well as the potential for using a glass substrate. These studies show that uniform, robust peptoid microsphere coatings can be formed using protic solvents, a full coverage administration technique, and drying in open air on silicon or glass substrates.

  7. 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.

  8. Inverse Limits of Uniform Covering Maps

    LaBuz, Brendon

    2008-01-01

    In ``Rips complexes and covers in the uniform category'' the authors define, following James, covering maps of uniform spaces and introduce the concept of generalized uniform covering maps. Conditions for the existence of universal uniform covering maps and generalized uniform covering maps are given. This paper notes that the universal generalized uniform covering map is uniformly equivalent to the inverse limit of uniform covering maps and is therefore approximated by uniform covering maps....

  9. 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,…

  10. Comments on Beckmann's Uniform Reducts

    Cook, Stephen

    2006-01-01

    Arnold Beckmann defined the uniform reduct of a propositional proof system f to be the set of those bounded arithmetical formulas whose propositional translations have polynomial size f-proofs. We prove that the uniform reduct of f + Extended Frege consists of all true bounded arithmetical formulas iff f + Extended Frege simulates every proof system.

  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. Adjustable, Broadband, Selective Excitation with Uniform Phase

    Cano, Kristin E.; Smith, Mari A.; Shaka, A. J.

    2002-03-01

    An advance in the problem of achieving broadband, selective, and uniform-phase excitation in NMR spectroscopy of liquids is outlined. Broadband means that, neglecting relaxation, any frequency bandwidth may be excited even when the available radiofrequency (RF) field strength is strictly limited. Selective means that sharp transition edges can be created between pure-phase excitation and no excitation at all. Uniform phase means that, neglecting spin-spin coupling, all resonance lines have nearly the same phase. Conventional uniform-phase excitation pulses (e.g., E-BURP), mostly based on amplitude modulation of the RF field, are not broadband: they have an achievable bandwidth that is strictly limited by the peak power available. Other compensated pulses based on adiabatic half-passage, like BIR-4, are not selective. By contrast, inversion pulses based on adiabatic fast passage can be broadband (and selective) in the sense above. The advance outlined is a way to reformulate these frequency modulated (FM) pulses for excitation, rather than just inversion.

  13. 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.

  14. Uniform rectifiability and harmonic measure I: Uniform rectifiability implies Poisson kernels in $L^p$

    Hofmann, Steve

    2012-01-01

    We present a higher dimensional, scale-invariant version of a classical theorem of F. and M. Riesz. More precisely, we establish scale invariant absolute continuity of harmonic measure with respect to surface measure, along with higher integrability of the Poisson kernel, for a domain $\\Omega\\subset \\re^{n+1},\\, n\\geq 2$, with a uniformly rectifiable boundary, which satisfies the Harnack Chain condition plus an interior (but not exterior) corkscrew condition. In a companion paper to this one \\cite{HMU}, we also establish a converse, in which we deduce uniform rectifiability of the boundary, assuming scale invariant $L^q$ bounds, with $q>1$, on the Poisson kernel.

  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. Local Rigidity Of Uniform Lattices

    Gelander, Tsachik; Levit, Arie

    2016-01-01

    We establish local topological rigidity for uniform lattices in compactly generated groups, extending the result of Weil from the realm of Lie groups. We generalize the classical local rigidity theorem of Selberg, Calabi and Weil to irreducible uniform lattices in $\\text{Isom}(X)$ where $X$ is a proper $\\text{CAT}(0)$ space with no Euclidian factors, not isometric to the hyperbolic plane. We deduce an analog of Wang's finiteness theorem for certain non-positively curved metric spaces.

  17. 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…

  18. Non-uniform Hyperbolicity and Non-uniform Specification

    Oliveira, Krerley

    2011-01-01

    Let $f$ be a $C^{1+\\alpha}\\,(\\alpha>0)$ diffeomorphism and $\\mu$ be an ergodic hyperbolic measure of $f$. We show that this system $(f,\\mu)$ naturally satisfies non-uniform specification property\\cite{STV}(see Definition \\ref{Def:NS}) and thus we can delete the assumption of non-uniform specification property in the main Theorem \\cite{STV} to establish an inequality between Lyapunov exponents and local recurrence properties. We also discuss generalized non-uniform specification property with respect to arbitrarily finite(infinite) orbit segments. Moreover, these results are also valid for any ergodic hyperbolic measure $\\mu$, in whose Oseledec splitting the stable bundle dominates the unstable bundle on the support of $\\mu$.

  19. Irradiation uniformity of spherical targets by multiple uv beams from OMEGA

    Direct-drive laser fusion demands extremely high levels of irradiation uniformity to ensure uniform compression of spherical targets. The assessment of illumination uniformity of targets irradiated by multiple beams from the OMEGA facility is made with the aid of multiple beams spherical superposition codes, which take into account ray tracing and absorption and a detailed knowledge of the intensity distribution of each beam in the target plane. In this report, recent estimates of the irradiation uniformity achieved with 6 and 12 uv beams of OMEGA will be compared with previous measurements in the IR, and predictions will be made for the uv illumination uniformity achievable with 24 beams of OMEGA

  20. Uniform laser ablation via photovoltaic effect of phthalocyanine/perylene derivative

    A uniform laser ablation was observed in a polystyrene film coated with a photovoltaic perylene/phthalocyanine bilayer when an incident took place at an intensity range of 109-1010 W/cm2 (λ=1064 nm, 1.1 ns FWHM). Without the bilayer coating, the laser pulse formed spiky structures in the polystyrene film as self-focusing traces of the laser pulse, while for the coated film, the uniform surface ablation trace without the spiky interior structures was observed. In the case of incident of 532 nm where the coating material exhibits no reflection, such difference depending the coating was not observed. These phenomena were coupled with the reflection and conduction properties via its photovoltaic effect, and agreed with the required ablation to achieve high-density compression of the fuel capsule for inertial fusion energy (IFE)

  1. Uniform laser ablation via photovoltaic effect of phthalocyanine/perylene derivative

    Nagai, Keiji; Yoshida, Hidetsugu; Norimatsu, Takayoshi; Miyanaga, Noriaki; Izawa, Yasukazu; Yamanaka, Tatsuhiko

    2002-09-30

    A uniform laser ablation was observed in a polystyrene film coated with a photovoltaic perylene/phthalocyanine bilayer when an incident took place at an intensity range of 10{sup 9}-10{sup 10} W/cm{sup 2} ({lambda}=1064 nm, 1.1 ns FWHM). Without the bilayer coating, the laser pulse formed spiky structures in the polystyrene film as self-focusing traces of the laser pulse, while for the cd film, the uniform surface ablation trace without the spiky interior structures was observed. In the case of incident of 532 nm where the coating material exhibits no reflection, such difference depending the coating was not observed. These phenomena were coupled with the reflection and conduction properties via its photovoltaic effect, and agreed with the required ablation to achieve high-density compression of the fuel capsule for inertial fusion energy (IFE)

  2. 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

    2013-11-01

    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. PMID:24514935

  3. 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.

  4. Harmonious coloring of uniform hypergraphs

    Bartłomiej Bosek; Sebastian Czerwiński; Jarosław Grytczuk; Paweł Rzążewski

    2016-01-01

    A \\emph{harmonious coloring} of a $k$-uniform hypergraph $H$ is a vertex coloring such that no two vertices in the same edge share the same color, and each $k$-element subset of colors appears on at most one edge. The \\emph{% harmonious number} $h(H)$ is the least number of colors needed for such a coloring. %These notions arose as a natural extension of a widely studied %topic of harmonious coloring of simple graphs. We prove that $k$-uniform hypergraphs of bounded maxim...

  5. 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....

  6. Uniform excitations in magnetic nanoparticles

    Steen Mørup

    2010-11-01

    Full Text Available 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. C-V uniformity measurements

    Ion implantation's unique contributions to FET processing are excellent uniformity and repeatability at low dose. These could be verified on product wafers but were difficult to measure on monitor wafers. This paper presents an MOS technique that integrates the C-V curve directly to obtain part of the implanted dose - the partial dose. This technique is fast and insensitive to measurement noise and dot-diameter variation. It uses standard MOS wafers and processing. Neither photo-defined dots nor special substrates are required. Presently the integral CdV technique for partial dose is used in several FET lines to measure both implant repeatability and uniformity. (orig.)

  8. Optimal geometry toward uniform current density electrodes

    Electrodes are commonly used to inject current into the human body in various biomedical applications such as functional electrical stimulation, defibrillation, electrosurgery, RF ablation, impedance imaging, and so on. When a highly conducting electrode makes direct contact with biological tissues, the induced current density has strong singularity along the periphery of the electrode, which may cause painful sensation or burn. Especially in impedance imaging methods such as the magnetic resonance electrical impedance tomography, we should avoid such singularity since more uniform current density underneath a current-injection electrode is desirable. In this paper, we study an optimal geometry of a recessed electrode to produce a well-distributed current density on the contact area under the electrode. We investigate the geometry of the electrode surface to minimize the edge singularity and produce nearly uniform current density on the contact area. We propose a mathematical framework for the uniform current density electrode and its optimal geometry. The theoretical results are supported by numerical simulations

  9. 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.

  10. Uniform rectifiability and harmonic measure I: Uniform rectifiability implies Poisson kernels in $L^p$

    Hofmann, Steve; Martell, José María

    2012-01-01

    We present a higher dimensional, scale-invariant version of a classical theorem of F. and M. Riesz. More precisely, we establish scale invariant absolute continuity of harmonic measure with respect to surface measure, along with higher integrability of the Poisson kernel, for a domain $\\Omega\\subset \\mathbb{R}^{n+1},\\, n\\geq 2$, with a uniformly rectifiable boundary, which satisfies the Harnack Chain condition plus an interior (but not exterior) corkscrew condition. In a companion paper to th...

  11. Uniformity calibration for ICT image

    The uniformity of ICT image is impaired by beam hardening and the inconsistency of detector units responses. The beam hardening and the nonlinearity of the detector's output have been analyzed. The correction factors are determined experimentally by the detector's responses with different absorption length. The artifacts in the CT image of a symmetrical aluminium cylinder have been eliminated after calibration. (author)

  12. 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…

  13. 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...... of the sublattice magnetization vectors, results in a contribution to the susceptibility, which increases with increasing temperature....

  14. Group Composition, Group Interaction and Achievement in Cooperative Small Groups.

    Webb, Noreen M.

    This study investigated interaction and achievement in cooperative small groups in four junior high school mathematics classrooms. Ninety-six students learned a one-week unit on consumer mathematics in mixed-ability or uniform-ability groups. Students in mixed-ability groups scored higher on a problem-solving test than students in uniform-ability…

  15. Micropatterning on cylindrical surfaces via electrochemical etching using laser masking

    Highlights: • Various micropatterns were fabricated on the cylindrical surface of a stainless steel shaft. • Selective electrochemical dissolution was achieved via a series process of laser masking and electrochemical etching. • Laser masking characteristics on the non-planar surface were investigated. • A uniform mask layer was formed on the cylindrical surface via synchronized laser line scanning with a rotary system. • The characteristics of electrochemical etching on the non-planar surface were investigated. - Abstract: This paper proposes a method of selective electrochemical dissolution on the cylindrical surfaces of stainless steel shafts. Selective electrochemical dissolution was achieved via electrochemical etching using laser masking. A micropatterned recast layer was formed on the surface via ytterbium-doped pulsed fiber laser irradiation. The micropatterned recast layer could be used as a mask layer during the electrochemical etching process. Laser masking condition to form adequate mask layer on the planar surface for etching cannot be used directly on the non-planar surface. Laser masking condition changes depending on the morphological surface. The laser masking characteristics were investigated in order to form a uniform mask layer on the cylindrical surface. To minimize factors causing non-uniformity in the mask layer on the cylindrical surface, synchronized laser line scanning with a rotary system was applied during the laser masking process. Electrochemical etching characteristics were also investigated to achieve deeper etched depth, without collapsing the recast layer. Consequently, through a series process of laser masking and electrochemical etching, various micropatternings were successfully performed on the cylindrical surfaces

  16. Achieving Standardization

    Henningsson, Stefan

    2016-01-01

    International e-Customs is going through a standardization process. Driven by the need to increase control in the trade process to address security challenges stemming from threats of terrorists, diseases, and counterfeit products, and to lower the administrative burdens on traders to stay...... 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...... to be harmonized in order for a global company to perceive e-Customs as standardized. In doing so, they contribute an explanation of the challenges associated with using a standardization mechanism for harmonizing socio-technical information systems....

  17. Achieving Standardization

    Henningsson, Stefan

    2014-01-01

    International e-Customs is going through a standardization process. Driven by the need to increase control in the trade process to address security challenges stemming from threats of terrorists, diseases, and counterfeit products, and to lower the administrative burdens on traders to stay...... 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...... to be harmonized in order for a global company to perceive e-Customs as standardized. In doing so, they contribute an explanation of the challenges associated with using a standardization mechanism for harmonizing socio-technical information systems....

  18. Improving the electrochemical properties of Li{sub 1.2}Mn{sub 0.52}Co{sub 0.08}Ni{sub 0.2}O{sub 2} cathode material by uniform surface nanocoating with samarium fluoride through depositional-hydrothermal route

    Lu, Chao; Wu, Hao, E-mail: hao.wu@scu.edu.cn; Chen, Baojun; Liu, Heng; Zhang, Yun, E-mail: y_zhang@scu.edu.cn

    2015-06-15

    Graphical abstract: Li{sub 1.2}Mn{sub 0.52}Co{sub 0.08}Ni{sub 0.2}O{sub 2} cathode material uniformly nanocoated with samarium fluoride (SmF{sub 3}) has been successfully synthesized through a chemical deposition method followed by low-temperature hydrothermal treatment. The surface modified cathode shows a significantly improved cycling stability and rate capability. - Highlights: • Samarium fluoride is originally used as coating material of Li-rich layered cathode. • Low-temperature hydrothermal treatment is employed to establish uniform surface coating. • Cathode nanocoated with SmF{sub 3} shows improved rate capability and cycling stability. • Coating material suppresses the side reaction between electrode and electrolyte. - Abstract: Surface nanocoating of lithium-rich layered Li{sub 1.2}Mn{sub 0.52}Co{sub 0.08}Ni{sub 0.2}O{sub 2} with samarium fluoride (SmF{sub 3}) has been performed through a chemical deposition route combined with a low-temperature hydrothermal treatment. The surface-modified Li{sub 1.2}Mn{sub 0.52}Co{sub 0.08}Ni{sub 0.2}O{sub 2} particles are uniformly and completely covered by an amorphous SmF{sub 3} protective layer with a thin thickness of ∼20 nm. After surface modification, the coated Li{sub 1.2}Mn{sub 0.52}Co{sub 0.08}Ni{sub 0.2}O{sub 2} as cathode shows a significantly improved cycling stability, keeping a capacity retention of 84.5% after 150 cycles at 2 C, much higher than 68.9%forits uncoated counterpart. Moreover, the coated sample delivers an enhanced rate capability with an average capacity of ∼132.3 mA h g{sup −1} when charged at 5 C and discharged at 0.2 C, while the uncoated counterpart only exhibits a capacity of ∼111.4 mA h g{sup −1} under the same conditions. Our results reveal that the remarkably improved electrochemical performance of the surface-modified cathode is attributed to the presence of uniform, robust, and nanoscale SmF{sub 3} coating layer, which not only suppresses the growth of SEI layer

  19. Magnetic Propeller for Uniform Magnetic Field Levitation

    Krinker, Mark

    2008-01-01

    Three new approaches to generating thrust in uniform magnetic fields are proposed. The first direction is based on employing Lorentz force acting on partial magnetically shielded 8-shaped loop with current in external magnetic field, whereby a net force rather than a torque origins. Another approach, called a Virtual Wire System, is based on creating a magnetic field having an energetic symmetry (a virtual wire), with further superposition of external field. The external field breaks the symmetry causing origination of a net force. Unlike a wire with current, having radial energetic symmetry, the symmetry of the Virtual Wire System is closer to an axial wire. The third approach refers to the first two. It is based on creation of developed surface system, comprising the elements of the first two types. The developed surface approach is a way to drastically increase a thrust-to-weight ratio. The conducted experiments have confirmed feasibility of the proposed approaches.

  20. 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.

  1. 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

  2. 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.

  3. Uniform beam distributions using octupoles

    The Gaussian beam profile of the BNL 200 MeV H- Linac beam at the Radiation Effects Facility target location was transformed into a rectangular profile with almost uniform distribution by placing two octupole magnetic elements at particular locations along the beam line. Experimental results of the beam profile projection in the horizontal and vertical planes, with and without octupoles, are presented and compared with third order calculations. 7 refs., 3 figs

  4. Uniform pricing and social welfare

    Bertoletti, Paolo

    2005-01-01

    We re-examine the case for uniform pricing in a monopolistic third-degree price-discrimination setting by introducing differentiated costs. A profit-maximizing monopolist could then use price differentiation to reduce the production of the more costly goods, thereby decreasing average cost and increasing welfare. Indeed, monopolistic price differentiation can improve welfare and also aggregate consumer surplus even if, as in the benchmark linear case, total output does not increase. According...

  5. 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°.

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

    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. - Highlights: • PTFE surfaces were treated with direct CF4 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°

  7. Topologies of (strong) uniform convergence on bornologies

    Holá, Lubica; Novotný, Branislav

    2012-01-01

    We continue the study of topologies of strong uniform convergence on bornologies initiated in [G. Beer and S. Levi, Strong uniform continuity, J. Math Anal. Appl., 350:568-589, 2009] and [G. Beer and S. Levi, Uniform continuity, uniform convergence and shields, Set-Valued and Variational Analysis, 18:251-275, 2010]. We study cardinal invariants of topologies of (strong) uniform convergence on bornologies on the space of continuous real-valued functions and we also generalize some known result...

  8. Vertical uniformity of cells and nuclei in epithelial monolayers.

    Neelam, Srujana; Hayes, Peter Robert; Zhang, Qiao; Dickinson, Richard B; Lele, Tanmay P

    2016-01-01

    Morphological variability in cytoskeletal organization, organelle position and cell boundaries is a common feature of cultured cells. Remarkable uniformity and reproducibility in structure can be accomplished by providing cells with defined geometric cues. Cells in tissues can also self-organize in the absence of directing extracellular cues; however the mechanical principles for such self-organization are not understood. We report that unlike horizontal shapes, the vertical shapes of the cell and nucleus in the z-dimension are uniform in cells in cultured monolayers compared to isolated cells. Apical surfaces of cells and their nuclei in monolayers were flat and heights were uniform. In contrast, isolated cells, or cells with disrupted cell-cell adhesions had nuclei with curved apical surfaces and variable heights. Isolated cells cultured within micron-sized square wells displayed flat cell and nuclear shapes similar to cells in monolayers. Local disruption of nuclear-cytoskeletal linkages resulted in spatial variation in vertical uniformity. These results suggest that competition between cell-cell pulling forces that expand and shorten the vertical cell cross-section, thereby widening and flattening the nucleus, and the resistance of the nucleus to further flattening results in uniform cell and nuclear cross-sections. Our results reveal the mechanical principles of self-organized vertical uniformity in cell monolayers. PMID:26795751

  9. Two inhomogeneities of irregular shape with internal uniform stress fields interacting with a screw dislocation

    Wang, Xu; Schiavone, Peter

    2016-07-01

    Using complex variable methods and conformal mapping techniques, we demonstrate rigorously that two inhomogeneities of irregular shape interacting with a screw dislocation can indeed maintain uniform internal stress distributions. Our analysis indicates that while the internal uniform stresses are independent of the existence of the screw dislocation, the shapes of the two inhomogeneities required to achieve this uniformity depend on the Burgers vector, the location of the screw dislocation, and the size of the inhomogeneities. In addition, we find that this uniformity of the internal stress field is achievable also when the two inhomogeneities interact with an arbitrary number of discrete screw dislocations in the matrix.

  10. 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.

  11. Light beams focusing in periodically non-uniform crystalline medium

    S.N.Kurilkina

    2002-03-01

    Full Text Available In the present paper the peculiarities of propagation and diffraction of optical waves in the crystalline periodically non-uniform media are considered. The dependence of light beam divergence in the crystal on curvatures of wave vector surface is obtained. It is shown, that presence of the periodic non-uniformity of the crystal and natural anisotropy lead to essential deformation of wave vector surface, namely, to the appearance of local regions with negative curvature and, hence, to the effect of light focusing in corresponding directions. The application of uniform electric field may intensify the light focusing. The crystalline diffraction lenses are proposed which are controlled by electric field and variation of incident light polarization.

  12. Uniform rectifiability and harmonic measure II: Poisson kernels in $L^p$ imply uniform rectifiability

    Hofmann, Steve; Uriarte-Tuero, Ignacio

    2012-01-01

    We present the converse to a higher dimensional, scale-invariant version of a classical theorem of F. and M. Riesz. More precisely, for $n\\geq 2$, for an ADR domain $\\Omega\\subset \\re^{n+1}$ which satisfies the Harnack Chain condition plus an interior (but not exterior) Corkscrew condition, we show that absolute continuity of harmonic measure with respect to surface measure on $\\partial\\Omega$, with scale invariant higher integrability of the Poisson kernel, is sufficient to imply uniformly rectifiable of $\\partial\\Omega$.

  13. 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:

  14. Investigation of light output uniformity and performance using a UV transmitting glass optic for a multi-UV LED array

    Jasenak, Brian; Willsey, Rachel; Willsey, Adam; Forish, James

    2016-03-01

    Ultraviolet light-emitting diode (UV LED) adoption is accelerating; they are being used in new applications such as UV curing, germicidal irradiation, nondestructive testing, and forensic analysis. In many of these applications, it is critically important to produce a uniform light distribution and consistent surface irradiance. Flat panes of fused quartz, silica, or glass are commonly used to cover and protect multi-UV LED arrays. However, they don't offer the advantages of an optical lens design. An investigation was conducted to determine the effect of a secondary glass optic on the uniformity of the light distribution and irradiance. Glass optics capable of transmitting UV-A, UV-B, and UV-C wavelengths can improve light distribution and intensity. In this study, a UV transmitting glass formulation and secondary linear optic were designed and manufactured to demonstrate their effects on achievable irradiance intensity and uniformity. Prismatic patterning on the light source surface of the lens was used to minimize reflection losses on the incident surface of the glass. Fresnel optics were molded into the opposite side of the UV transmitting glass to control the refraction of the light and to gain the desired light intensity distribution from two multi-UV LED arrays. A 20% increase in relative irradiance was observed while maintaining the same coverage area. This work discusses the optical design and the resulting benefits of controlled light output on UV LED systems, which include reduced driving current, decreased thermal deterioration, improved energy efficiency, and longer LED lifetime.

  15. Increase in the Hydrophilicity and Lewis Acid-Base Properties of Solid Surfaces Achieved by Electric Gliding Discharge in Humid Air: Effects on Bacterial Adherence

    J. O. KAMGANG; M. NAITAL; J.-M. HERRY; M.-N. BELLON-FONTAINE; J.-L. BRISSET; R. BRIANDET

    2009-01-01

    This study addressed the effects of treatment with gliding discharge plasma on the surface properties of solid materials, as well as the consequences concerning adherence of a mode bacterium. As evaluated by contact angles with selected liquids, plasma treatment caused an increase in surface hydrophilicity and in the Lewis acid-base components of the surface energy of all materials tested. These modifications were more marked for low density polyethylene and stainless steel than for polytetrafluoroethylene. After treatment, the hydrophilicity of the materials remained relatively stable for at least 20 days. Moreover, analysis of the topography of the materials by atomic force microscopy revealed that the roughness of both polymers was reduced by glidarc plasma treatment. As a result of all these modifications, solid substrates were activated towards micro-organisms and the adherence of S. epidermidis, a negatively charged Lewis-base and mildly hydrophilic strain selected as the model, was increased in almost all the cases tested.

  16. Increase in the Hydrophilicity and Lewis Acid-Base Properties of Solid Surfaces Achieved by Electric Gliding Discharge in Humid Air: Effects on Bacterial Adherence

    This study addressed the effects of treatment with gliding discharge plasma on the surface properties of solid materials, as well as the consequences concerning adherence of a model bacterium. As evaluated by contact angles with selected liquids, plasma treatment caused an increase in surface hydrophilicity and in the Lewis acid-base components of the surface energy of all materials tested. These modifications were more marked for low density polyethylene and stainless steel than for polytetrafluoroethylene. After treatment, the hydrophilicity of the materials remained relatively stable for at least 20 days. Moreover, analysis of the topography of the materials by atomic force microscopy revealed that the roughness of both polymers was reduced by glidarc plasma treatment. As a result of all these modifications, solid substrates were activated towards micro-organisms and the adherence of S. epidermidis, a negatively charged Lewis-base and mildly hydrophilic strain selected as the model, was increased in almost all the cases tested. (plasma technology)

  17. 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

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

    Duy Tien Ta

    2016-07-01

    Full Text Available 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.

  19. Nurses’ uniforms: How many bacteria do they carry after one shift?

    Sanon, Marie-Anne; Watkins, Sally

    2012-01-01

    This pilot study investigated the pathogens that nurses are potentially bringing into the public and their home when they wear work uniforms outside of the work environment. To achieve this, sterilized uniforms were distributed to 10 nurses at a local hospital in Washington State at the beginning of their shift. Worn uniforms were collected at the end of the shifts and sent to a laboratory for analysis. Four tests were conducted: 1) a heterotrophic growth plate count, 2) methicillin-resistant...

  20. Uniform Coverage Bounds for Confidence Intervals and Berry-Esseen Theorems for Edgeworth Expansion

    Hall, Peter; Jing, Bing-Yi

    1995-01-01

    We derive upper bounds for the coverage error of confidence intervals for a population mean uniformly over large classes of populations and different types of confidence intervals. It is shown that the order of these bounds is achieved by the normal approximation method for constructing confidence intervals, uniformly over distributions with finite third moment, and, by an empirical Edgeworth correction of this approach, uniformly over smooth distributions with finite fourth moments. These re...

  1. Development of Fresnel-based Concentrated Photovoltaic (CPV) System with Uniform Irradiance

    Irfan Ullah

    2014-01-01

    Different designs have been presented to achieve high concentration and uniformity for the concentrated photovoltaic (CPV) system. Most of the designs have issues of low efficiency in terms of irradiance uniformity. To this end, we present a design methodology to increase irradiance uniformity over solar cell. The system consists of an eight-fold Fresnel lens as a primary optical element (POE) and an optical lens, which consists of eight parts, as a secondary optical element (SOE). Sunlight i...

  2. Dense packing on uniform lattices

    Eloranta, Kari

    2009-01-01

    We study the Hard Core Model on the graphs ${\\rm {\\bf \\scriptstyle G}}$ obtained from Archimedean tilings i.e. configurations in $\\scriptstyle \\{0,1\\}^{{\\rm {\\bf G}}}$ with the nearest neighbor 1's forbidden. Our particular aim in choosing these graphs is to obtain insight to the geometry of the densest packings in a uniform discrete set-up. We establish density bounds, optimal configurations reaching them in all cases, and introduce a probabilistic cellular automaton that generates the legal configurations. Its rule involves a parameter which can be naturally characterized as packing pressure. It can have a critical value but from packing point of view just as interesting are the noncritical cases. These phenomena are related to the exponential size of the set of densest packings and more specifically whether these packings are maximally symmetric, simple laminated or essentially random packings.

  3. Uniform distribution of Hasse invariants

    R. A. Mollin

    1985-03-01

    Full Text Available I. Schur's study of simple algebras around the turn of the century, and subsequent investigations by R. Brauer, E. Witt and others, were later reformulated in terms of what is now called the Schur subgroup of the Brauer group. During the last twenty years this group has generated substantial interest and numerous palatable results have ensued. Among these is the discovery that elements of the Schur group satisfy uniform distribution of Hasse invariants. It is the purpose of this paper to continue an investigation of the latter concept and to highlight certain applications of these results, not only to the Schur group, but also to embeddings of simple algebras and extensions of automorphisms, among others.

  4. 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)

  5. Spatial Non-uniformity Measurements of Large Area Silicon Photodiodes

    DURAK, Murat; SAMADOV, Farhad; TÜRKOĞLU, A. Kamuran

    2002-01-01

    Accurate determination of the responsivity of silicon photodiodes are highly desired in photometry. The change of responsivity over the surface, the so-called spatial non-uniformity, effects power measurements especially in photodiodes with large active areas. To study this effect, first an intensity-stabilized laser source-optics has been established. A purpose-built step-motor controlled two axis micro mechanical stage has been designed to scan the photodiode surface. In this stu...

  6. Spacetime transformations from a uniformly accelerated frame

    We use the generalized Fermi–Walker transport to construct a one-parameter family of inertial frames which are instantaneously comoving to a uniformly accelerated observer. We explain the connection between our approach and that of Mashhoon. We show that our solutions of uniformly accelerated motion have constant acceleration in the comoving frame. Assuming the weak hypothesis of locality, we obtain local spacetime transformations from a uniformly accelerated frame K′ to an inertial frame K. The spacetime transformations between two uniformly accelerated frames with the same acceleration are Lorentz. We compute the metric at an arbitrary point of a uniformly accelerated frame. (paper)

  7. 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 are in...... fact completely consistent with Uniformity. I report on an analysis of all examples in the Copenhagen Dependency Treebanks involving violations of Uniformity. I argue that they are in fact all consistent with Uniformity, and conclude that the CDT should be revised to reflect this....

  8. 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.

  9. Back to the Basics: In Defense of Achievement (and Achievement Tests) in College Admissions

    Geiser, Saul

    2009-01-01

    In this article, the author describes the growth and acceptance of achievement tests, such as the Scholastic Aptitude Test (SAT), over the past century, advocating that many SAT claims of equity, uniformity, technical reliability, and prediction, over traditional measures of academic achievement have been found to be illusory. Summarizing a series…

  10. Realization of perfect reconstruction non-uniform filter banks via a tree structure

    Ling, Wing-Kuen; Tam, Kwong-Shun

    2001-01-01

    Obviously, a tree structure filter bank can be realized via a non-uniform filter bank, and perfect reconstruction is achieved if and only if each branch of the tree structure can provide perfect reconstruction. In this paper, the converse of this problem is studied. We show that a perfect reconstruction non-uniform filter bank with decimation ratio {2,4,4} can be realized via a tree structure and each branch of the tree structure achieves perfect reconstruction.

  11. Chemical Sintering Generates Uniform Porous Hyaluronic Acid Hydrogels

    Cam, Cynthia; Segura, Tatiana

    2013-01-01

    Implantation of scaffolds for tissue repair has been met with limited success primarily due to the inability to achieve vascularization within the construct. Many strategies have shifted to incorporate pores into these scaffolds to encourage rapid cellular infiltration and subsequent vascular ingrowth. We utilized an efficient chemical sintering technique to create a uniform network of polymethyl methacrylate (PMMA) microspheres for porous hyaluronic acid hydrogel formation. The porous hydrog...

  12. 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.

  13. Leader propagation in uniform background fields in SF6

    The breakdown mechanism of compressed SF6 in gas insulation is known to be controlled by stepped leader propagation. This process is still not well understood in uniform and weakly non-uniform background fields with small electrode protrusions, such as particles or surface roughness. In a previous publication an investigation of partial discharges and breakdown in uniform background fields that focused on streamer and leader inception mechanisms was presented (Seeger et al 2008 J. Phys. D: Appl. Phys. 41 185204). In this paper we present for the first time a physical leader propagation model that consistently describes the observed phenomena in uniform background fields in SF6. The model explains two different types of leader breakdown; these can be associated with the precursor and the stem mechanisms. It also yields the parameters of stepped leader propagation, which include step lengths, associated step charges, step times and fields and temperatures in the leader channel. Further, it explains the features of arrested leaders in uniform background fields. The model predicts the range of parameters under which arrested and breakdown leaders occur in good agreement with the experimental data.

  14. Low-energy electron transport in non-uniform media

    We simulated the transport of low and medium energy electrons with energies between 1.26 eV and 10 keV in non-uniform carbon targets using the track structure Monte Carlo code TRAX which has several applications in biophysics and radiation physics. Cross sections for electrons incident on carbon have been critically assessed. Furthermore the code has been extended to handle non-uniform targets allowing a complex geometry description. Solid state targets, which are commonly used as targets in electron spectrometers and other devices can be non-uniform, e.g. have highly irregular surfaces or pinholes. The resulting electron spectra can be significantly affected by these non-uniformities. We reproduce experimental data obtained by GSI’s Toroid electron spectrometer using thin solid state foils as targets. This unique experiment was designed to gain further insight in the emission and transport of low energy electrons in solids to improve the description of microscopic energy deposition. The realistic implementation of non-uniform targets in TRAX was verified by comparison with available experimental data. The increased backscattering due to the roughness of an unpolished target in comparison with polished ones could be reproduced as well as secondary electron spectra from the Toroid

  15. 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...

  16. Cultural Inertia and Uniformity in Organizations

    Carrillo, Juan D; Gromb, Denis

    2002-01-01

    We analyse aspects of the structure of organizational culture. We show that old and culturally uniform organizations are prone to cultural inertia; that is they are reluctant to adopt a different culture in response to a change in the environment. Cultural uniformity can be beneficial because the associated inertia protects and therefore encourages culture-specific investments by agents within the organization. We also explore the model’s implications for such issues as cultural uniformity wi...

  17. 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 ...

  18. 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.

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

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

    2011-01-01

    measurements may be useful for process uniformity characterization. The method is applied for characterization of TiW coated nanograss uniformity. Three-way flexible L-shaped cantilever electrodes are used to avoid damage to the fragile surface, and a relative standard deviation on measurement repeatability of...

  20. 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 conditions...... quickly. This paper also proposes an effective and quick response technique to find the MPP of PV array among Global Peak (GP) and local peaks when PSC occurs based on the analytic condition. It also can perform in a manner like conventional MPPT method when the insolation conditions are uniform. In order...

  1. Some results on uniform arithmetic circuit complexity

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

    1994-01-01

    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 that...

  2. 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…

  3. 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…

  4. 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)

  5. 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…

  6. Uniformity in a Dual Assessment System

    Chicoine, David L.; Giertz, J. Fred

    1988-01-01

    Variation in property tax assessment uniformity is studied using data from a "dual" assessment structure where county assessment authority overlaps township assessing responsibility and elected local assessors work with appointed county assessment officers. Particular attention is given to the impact of the size and organization of assessment jurisdictions on assessment uniformity.

  7. Devaney's chaos on uniform limit maps

    Highlights: → The transitivity may not been inherited even if the sequence functions mixing. → The sensitivity may not been inherited even if the iterates of sequence have some uniform convergence. → Some equivalence conditions for the transitivity and sensitivity for uniform limit function are given. → A non-transitive sequence may converge uniformly to a transitive map. - Abstract: Let (X, d) be a compact metric space and fn : X → X a sequence of continuous maps such that (fn) converges uniformly to a map f. The purpose of this paper is to study the Devaney's chaos on the uniform limit f. On the one hand, we show that f is not necessarily transitive even if all fn mixing, and the sensitive dependence on initial conditions may not been inherited to f even if the iterates of the sequence have some uniform convergence, which correct two wrong claims in . On the other hand, we give some equivalence conditions for the uniform limit f to be transitive and to have sensitive dependence on initial conditions. Moreover, we present an example to show that a non-transitive sequence may converge uniformly to a transitive map.

  8. Radionic Non-uniform Stable Black Strings

    Tamaki, Takashi; Kanno, Sugumi; Soda, Jiro

    2003-01-01

    Non-uniform black strings in the two-brane system are investigated using the effective action approach. It is shown that the radion acts as a non-trivial hair of black strings. The stability of solutions is demonstrated using the catastrophe theory. The black strings are shown to be non-uniform.

  9. Radionic Non-Uniform Black Strings

    Tamaki, T.; Kanno, S.; Soda, J.

    Non-uniform black strings in the two-brane system are investigated using the effective action approach. It is shown that the radion acts as a non-trivial hair of black strings. The stability of solutions is demonstrated using the catastrophe theory. The black strings are shown to be non-uniform.

  10. 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.