Initial stage of flat plate impact onto liquid free surface
Iafrati, Alessandro; Korobkin, Alexander A.
2004-07-01
The liquid flow and the free surface shape during the initial stage of flat plate impact onto liquid half-space are investigated. Method of matched asymptotic expansions is used to derive equations of motion and boundary conditions in the main flow region and in small vicinities of the plate edges. Asymptotic analysis is performed within the ideal and incompressible liquid model. The liquid flow is assumed potential and two dimensional. The ratio of the plate displacement to the plate width plays the role of a small parameter. In the main region the flow is given in the leading order by the pressure-impulse theory. This theory provides the flow field around the plate after a short acoustic stage and predicts unbounded velocity of the liquid at the plate edges. In order to resolve the singular flow caused by the normal impact of a flat plate, the fine pattern of the flow in small vicinities of the plate edges is studied. It is shown that the initial flow close to the plate edges is self-similar in the leading order and is governed by nonlinear boundary-value problem with unknown shape of the free surface. The Kutta conditions are imposed at the plate edges, in order to obtain a nonsingular inner solution. This boundary-value problem is solved numerically by iterations. At each step of iterations the "inner" velocity potential is calculated by the boundary-element method. The asymptotics of the inner solution in both the far field and the jet region are obtained to make the numerical algorithm more efficient. The numerical procedure is carefully verified. Agreement of the computed free surface shape with available experimental data is fairly good. Stability of the numerical solution and its convergence are discussed.
Flat liquid crystal diffractive lenses with variable focus and magnification
Valley, Pouria
Non-mechanical variable lenses are important for creating compact imaging devices. Various methods employing dielectrically actuated lenses, membrane lenses, and liquid crystal lenses were previously proposed [1-4]. In This dissertation the design, fabrication, and characterization of innovative flat tunable-focus liquid crystal diffractive lenses (LCDL) are presented. LCDL employ binary Fresnel zone electrodes fabricated on Indium-Tin-Oxide using conventional micro-photolithography. The light phase can be adjusted by varying the effective refractive index of a nematic liquid crystal sandwiched between the electrodes and a reference substrate. Using a proper voltage distribution across various electrodes the focal length can be changed between several discrete values. Electrodes are shunted such that the correct phase retardation step sequence is achieved. If the number of 2pi zone boundaries is increased by a factor of m the focal length is changed from f to f/m based on the digitized Fresnel zone equation: f = rm2/2mlambda, where r m is mth zone radius, and lambda is the wavelength. The chromatic aberration of the diffractive lens is addressed and corrected by adding a variable fluidic lens. These LCDL operate at very low voltage levels (+/-2.5V ac input), exhibit fast switching times (20-150 ms), can have large apertures (>10 mm), and small form factor, and are robust and insensitive to vibrations, gravity, and capillary effects that limit membrane and dielectrically actuated lenses. Several tests were performed on the LCDL including diffraction efficiency measurement, switching dynamics, and hybrid imaging with a refractive lens. Negative focal lengths are achieved by adjusting the voltages across electrodes. Using these lenses in combination, magnification can be changed and zoom lenses can be formed. These characteristics make LCDL a good candidate for a variety of applications including auto-focus and zoom lenses in compact imaging devices such as camera
Soap, science, and flat-screen TVs a history of liquid crystals
Dunmur, David
2011-01-01
The terms 'liquid crystal' or 'liquid crystal display' (LCD) are well-known in the context of flat-screen televisions, but the properties and history of liquid crystals are little understood. This book tells the story of liquid crystals, from their controversial discovery at the end of the nineteenth century, to their eventual acceptance as another state of matter to rank alongside gases, liquids and solids. As their story unfolds, the scientists involved and their works are put into illuminating broader socio-political contexts. In recent years, liquid crystals have had a major impact on the display industry, culminating in the now widely available flat-screen televisions; this development is described in detail over three chapters, and the basic science behind it is explained in simple terms accessible to a general reader. New applications of liquid crystals in materials, bio-systems, medicine and technology are also explained.
Steady thermocapillary flows in a two-layer liquid system with flat interfaces
del Arco, E. Crespo; Extremet, G. P.; Sani, R. L.
1993-01-01
Steady thermocapillary convection is studied in a system of two flat, superposed layers of immiscible liquids with two fluid-fluid interfaces in a configuration similar to that of an encapsulated crystal growth. The layers are bounded on the sides by isothermal vertical walls maintained at different constant temperatures. A simplified analytical solution is used initially to explore different potential flow regimes in a parameter space of large dimensionality. Then the coupled Navier-Stokes and heat transfer equations are solved numerically with a finite element method via FIDAP, in a rectangular cavity filled with two immiscible liquids in the absence of a gravitational field.
Modeling of the deformation of a liquid droplet impinging upon a flat surface
Fukai, J.; Zhao, Z.; Poulikakos, D.; Megaridis, C. M.; Miyatake, O.
1993-11-01
This article presents a theoretical study of the deformation of a spherical liquid droplet impinging upon a flat surface. The study accounts for the presence of surface tension during the spreading process. The theoretical model is solved numerically utilizing deforming finite elements and grid generation to simulate accurately the large deformations, as well as the domain nonuniformities characteristic of the spreading process. The results document the effects of impact velocity, droplet diameter, surface tension, and material properties on the fluid dynamics of the deforming droplet. Two liquids with markedly different thermophysical properties, water and liquid tin, are utilized in the numerical simulations because of their relevance in the industrial processes of spray cooling and spray deposition, respectively. The occurrence of droplet recoiling and mass accumulation around the splat periphery are standout features of the numerical simulations and yield a nonmonotonic dependence of the maximum splat radius on time.
Capillary Forces between Submillimeter Spheres and Flat Surfaces at Constant Liquid Volumes
WANG Le-Feng; RONG Wei-Bin; SUN Li-Ning; CHEN Li-Guo; SHAO Bing
2009-01-01
We investigate the capillary forces between submillimeter spheres and flat surfaces at constant liquid volumes theoretically and experimentally.An iterative method is used to estimate the capillary force with contact angles as the boundary conditions and the constant volume as a constraint.The theoretical analysis shows that the maximum capillary force between them decreases with the increase of the liquid bridge volume at small contact angles.The experimental results show that the force is smaller than the theoretical values at the initial separation distances.It is also observed that the force first increases and then decreases with an increasing separation distance in some cases.These phenomena of capillary forces hysteresis are explained according to the wetting hysteresis.
Maji, Partha Sona
2014-01-01
We have performed a numerical analysis of the structural dependence of the PCF parameters towards ultra-flat dispersion in the C-band of communication wavelength. The technique is based on regular square-lattice PCF with all the air-hole of same uniform diameter and the effective size of the air-holes are modified with a selective infiltration of the air-holes with liquids. The dependence of the PCF structural parameters namely air-hole diameter and hole-to-hole distance along with the infiltrating liquid has been investigated in details. It is shown that the infiltrating liquid has critical influence on both the slope and value of dispersion, while pitch only changes the dispersion value whereas air-hole diameter modifies the slope of the dispersion. Our numerical investigation establishes dispersion values as small as 0+-0.58ps/(nm-km) over a bandwidth of 622nm in the communication wavelength band (C-band). The proposed design study will be very helpful in high power applications like broadband smooth super...
Flow of Liquid in Flat Gaps of the Satellite Motor Working Mechanism
Sliwiński Paweł
2014-04-01
Full Text Available The article describes the methodology and results of investigations of the flow of oil and HFA-E emulsion in flat gaps of the working mechanism of a satellite motor. The flow of liquid in those gaps is turbulent and not fully developed. The article presents two methods of modelling this flow. Method I makes use of the Darcy-Weisbach formula, while Method II bases on the assumption that in the variable-length gaps the flow is turbulent in the area where the length is the smallest and laminar where the length is the largest. Consequently, the flow in such gaps can be modelled as the sum of laminar and turbulent flows. The results obtained in the experiment have made the basis for calculating relevant coefficients and assessing the proportion of turbulence in the flow modelled using both methods
Amini, Amirhossein; Homsy, G. M.
2017-04-01
We study the evolution of the profile of a two-dimensional volatile liquid droplet that is evaporating on a flat heated substrate. We adopt a one-sided model with thermal control that, together with the lubrication approximation, results in an evolution equation for the local height of the droplet. Without requiring any presumption for the shape of the drop, the problem is formulated for the two modes of evaporation: a pinned contact line and a moving contact line with fixed contact angle. Numerical solutions are provided for each case. For the pinned contact line case, we observe that after a time interval the contact angle dynamics become nonlinear and, interestingly, the local contact angle goes to zero in advance of total evaporation of the drop. For the case of a moving contact line, in which the singularity at the contact line is treated by a numerical slip model, we find that the droplet nearly keeps its initial circular shape and that the contact line recedes with constant speed.
Design, construction and testing of a liquid-heating flat-plate solar collector
Tuttle, R E
1980-02-01
The purpose of this study was to design, construct, and test a liquid-heating flat-plate solar collector. From the literature search, information was gathered concerning the basic components of the collector, the different processes and materials that can be used in the construction of these components, and their advantages and disadvantages. The literature search also revealed a method used to measure the performance of the collector in terms of efficiency and heat output. Design considerations were then listed for each of the major components as well as the collector as a single unit. Then, each component was designed, taking into consideration the final assembly of the completed unit. Detailed designs were required for the absorber plate and the box and frame assembly because of their complexity in construction and assembly. Once the components were designed, the construction details were arranged in a logical sequence, again considering the final assembly of the unit. The collector was then carefully constructed and assembled following the design details. After the solar collector was assembled completely, tests were made, data were obtained and recorded, and a collector performance curve was developed.
INTERACTION OF LIQUID FLAT SCREENS WITH GAS FLOW RESTRICTED BY CHANNEL WALLS
S. T. Aksentiev
2005-01-01
Full Text Available The paper gives description of physical pattern of liquid screen interaction that are injected from the internal walls of a rectangular channel with gas flow. Criterion dependences for determination of intersection coordinates of external boundaries with longitudinal channel axis and factor of liquid screen head resistance.
Unsteady MHD convection in a flat horizontal layer of liquid with free boundaries
Antimirov, M.Ya.; Liyepinya, V.R.
1977-10-01
A complete solution is produced to the unsteady problem of the convective movement of a conducting fluid in a flat horizontal layer with free boundaries (in its linear statement) when an external magnetic field is present. Analysis of the solution produced allows the stability of motion to be studied and, furthermore, permits unambiguous determination of steady motion at the boundary of stability by a passage to the limit as t ..-->.. infinity in the unsteady solution at the critical Rayleigh number. 3 references.
Puvaneswari Puvaneswari
2016-01-01
Full Text Available The effect of conjugation on the enhancement of heat transfer in a liquid metal flow past a thermally conducting and sinusoidally oscillating infinite flat plate, when a constant temperature gradient is superimposed on the fluid, is investigated. The plate is made up of the materials compatible with the liquid metals used and is considered to be of finite thickness. Analytical solutions for the velocity and the temperature of the fluid and the solid are obtained. The effects of thermal conductivity and the thickness of the plate on the total time averaged heat flux transported and the thermal boundary layer thickness are investigated in detail. It is found that the effects of wall thickness and wall thermal conductivity on the heat flux transported depend on their effects on the transverse temperature gradient at any frequency. The optimum value of wall thickness at which the net heat flux transported attains the maximum value, for each fluid and for each wall material under consideration, is reported. A maximum increase of 46.14 % in the heat flux transported can be achieved by optimizing the wall thickness. A maximum convective heat flux of 1.87 × 108W/m2 is achieved using Na with AISI 316 wall. All the results obtained have been compared with the experimental and analytical results reported in the literature and are found to be in good agreement. It is believed that the new insights gained will be of significant use while designing liquid metal heat transfer systems.
Yoshida, Ken-ichi, E-mail: yoshida.kennichi71@jaea.go.jp; Nara, Takayuki; Saitoh, Yuichi; Yokota, Watalu [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)
2014-02-15
A flat distribution of the minimum magnetic field (flat-B{sub min}) of an electron cyclotron resonance ion source (ECRIS) is expected to perform better in highly charged ion production than classical B{sub min}. To form a flat-B{sub min} structure with a liquid helium-free superconducting device, a coil system of seven coils with four current leads has been designed. The lead number was reduced by connecting the plural coils in series to maintain the flat-B{sub min} structure even when the coil currents are changed for adjustment. This coil system can be operated with a helium-free cryostat, since the estimation of heat from the leads to the coils is nearly equivalent to the existing superconducting ECRIS of a similar type.
Equilibrium state of a cylindrical particle with flat ends in nematic liquid crystals.
Hashemi, S Masoomeh; Ejtehadi, Mohammad Reza
2015-01-01
A continuum theory is employed to numerically study the equilibrium orientation and defect structures of a circular cylindrical particle with flat ends under a homeotropic anchoring condition in a uniform nematic medium. Different aspect ratios of this colloidal geometry from thin discotic to long rodlike shapes and several colloidal length scales ranging from mesoscale to nanoscale are investigated. We show that the equilibrium state of this colloidal geometry is sensitive to the two geometrical parameters: aspect ratio and length scale of the particle. For a large enough mesoscopic particle, there is a specific asymptotic equilibrium angle associated to each aspect ratio. Upon reducing the particle size to nanoscale, the equilibrium angle follows a descending or ascending trend in such a way that the equilibrium angle of a particle with the aspect ratio bigger than 1:1 (a discotic particle) goes to a parallel alignment with respect to the far-field nematic, whereas the equilibrium angle for a particle with the aspect ratio 1:1 and smaller (a rodlike particle) tends toward a perpendicular alignment to the uniform nematic direction. The discrepancy between the equilibrium angles of the mesoscopic and nanoscopic particles originates from the significant differences between their defect structures. The possible defect structures related to mesoscopic and nanoscopic colloidal particles of this geometry are also introduced.
Efficiency of liquid flat-plate solar energy collector with solar tracking system
Chekerovska Marija
2015-01-01
Full Text Available An extensive testing programme is performed on a solar collector experimental set-up, installed on a location in Shtip (Republic of Macedonia, latitude 41º 45’ and longitude 22º 12’, in order to investigate the effect of the sun tracking system implementation on the collector efficiency. The set-up consists of two flat plate solar collectors, one with a fixed surface tilted at 30о towards the South, and the other one equipped with dual-axis rotation system. The study includes development of a 3-D mathematical model of the collectors system and a numerical simulation programme, based on the computational fluid dynamics (CFD approach. The main aim of the mathematical modelling is to provide information on conduction, convection and radiation heat transfer, so as to simulate the heat transfer performances and the energy capture capabilities of the fixed and moving collectors in various operating modes. The feasibility of the proposed method was confirmed by experimental verification, showing significant increase of the daily energy capture by the moving collector, compared to the immobile collector unit. The comparative analysis demonstrates a good agreement between the experimental and numerically predicted results at different running conditions, which is a proof that the presented CFD modelling approach can be used for further investigations of different solar collectors configurations and flow schemes.
Heat transfer within a flat micro heat pipe with extra liquid
Sprinceana, Silviu; Mihai, Ioan
2016-12-01
In the real functioning of flat micro heat pipe (FMHP), there can appear cases when the temperature from the vaporization zone can exceed a critical value caused by a sudden increase of the thermal flow. The heat transfer which is completed conductively through the copper wall of a FMHP vaporizer causes the vaporization of the work fluid. On the condenser, the condensation of the fluid vapors and the transfer of the condenser to the vaporizer can no longer be achieved. The solution proposed for enhancing heat transfer in the event of blockage phenomenon FMHP, it is the injection of a certain amount of working fluid in the vaporization zone. By this process the working fluid injected into the evaporator passes suddenly in the vapor, producing a cooling zone. The new product additional mass of vapor will leave the vaporization zone and will condense in condensation zone, thereby supplementing the amount of condensation. Thus resumes normal operating cycle of FMHP. For the experimental measurements made for the transfer of heat through the FMHP working fluid demineralized water, they were made two micro-capillary tubes of sintered copper layer. The first was filled with 1ml of demineralized water was dropped under vacuum until the internal pressure has reached a level of 1•104Pa. The second FMHP was filled with the same amount of working fluid was used and the same capillary inner layer over which was laid a polysynthetic material that will accrue an additional amount of fluid. In this case, the internal pressure was reduced to 1•104Pa.
Hydrometallurgical Recovery of Indium from Flat-Panel Displays of Spent Liquid Crystal Televisions
Inoue, Katsutoshi; Alam, Shafiq
2015-02-01
A recovery process for indium from waste liquid crystal display panels was developed on the basis of hydrometallurgical technology. The powdered sample was leached with 3 M HCl to extract its various metal constituents (indium, aluminum, tin, etc.). The mutual separation and subsequent recovery of the dissolved metals was achieved using two column adsorption tests: The first column was packed with a porous resin impregnated with Aliquat 336, a commercially available solvent extraction reagent based on a quaternary ammonium compound, and the resin contained in the second column was impregnated with Cyanex 923, also a commercially available solvent extraction reagent based on trialkylphosphine oxide. In the first column, tin, iron, and zinc were removed from the leach liquor. In the second column, only indium was selectively recovered. The metal ions trapped in these columns were eluted with 0.1 M H2SO4, yielding a solution purified indium solution with a concentration 10 times that of the feed solution.
Hsiao, Erik; Marino, Matthew J; Kim, Seong H
2010-12-15
This paper explains the origin of the vapor pressure dependence of the asperity capillary force in vapor environments. A molecular adsorbate layer is readily formed on solid surface in ambient conditions unless the surface energy of the solid is low enough and unfavorable for vapor adsorption. Then, the capillary meniscus formed around the solid asperity contact should be in equilibrium with the adsorbate layer, not with the bare solid surface. A theoretical model incorporating the vapor adsorption isotherm into the solution of the Young-Laplace equation is developed. Two contact geometries--sphere-on-flat and cone-on-flat--are modeled. The calculation results show that the experimentally-observed strong vapor pressure dependence can be explained only when the adsorption isotherm of the vapor on the solid surface is taken into account. The large relative partial pressure dependence mainly comes from the change in the meniscus size due to the presence of the adsorbate layer.
Fukai, J.; Shiiba, Y.; Yamamoto, T.; Miyatake, O.; Poulikakos, D.; Megaridis, C. M.; Zhao, Z.
1995-02-01
In this paper an experimental and theoretical study of the deformation of a spherical liquid droplet colliding with a flat surface is presented. The theoretical model accounts for the presence of inertia, viscous, gravitation, surface tension, and wetting effects, including the phenomenon of contact-angle hysteresis. Experiments with impingement surfaces of different wettability were performed. The study showed that the maximum splat radius decreased as the value of the advancing contact angle increased. The effect of impact velocity on droplet spreading was more pronounced when the wetting was limited. The experimental results were compared to the numerical predictions in terms of droplet deformation, splat radius, and splat height. The theoretical model predicted well the deformation of the impacting droplet, not only in the spreading phase, but also during recoiling and oscillation. The wettability of the substrate upon which the droplet impinges was found to affect significantly all phases of the spreading process, including the formation and development of a ring structure around the splat.
PEI Liang; WANG Liming; YU Guoqiang
2012-01-01
The Nd(Ⅲ) extraction in flat renewal supported liquid membrane (FRSLM),with polyvinylidene fluoride membrane and renewal solution including HNO3 solution as the stripping solution and di(2-ethylhexyl) phosphoric acid (D2EHPA) dissolved in kerosene as the membrane solution,was investigated.The effects of pH in the feed phase,volume ratio of membrane solution to stripping solution,concentration of HNO3 solution and concentration of carrier in the renewal phase on extraction of Nd(Ⅲ) were also studied,respectively.As a result,the optimum extraction conditions of Nd(Ⅲ) were obtained when concentration of HNO3 solution was 4.00 mol/L,concentration of D2EHPA was 0.100 mol/L,and volume ratio of membrane solution to stripping solution was 1.00 in the renewal phase,and pH was 4.60 in the feed phase.When initial concentration of Nd(Ⅲ) was 2.00× 10-4 mol/L,the extraction percentage of Nd(Ⅲ) was up to 92.9％ in 75 min.
Ge, Yang; Fan, L.-S.
2005-02-01
The hydrodynamics and heat transfer phenomena of a liquid droplet impacting upon a hot flat surface are analyzed based on three-dimensional (3D) numerical simulation considering film-boiling behavior. The 3D level-set method is employed to portray the droplet surface variation during its deformation. The governing equations for the droplet and the surrounding gas phase are solved utilizing the finite-volume method with the arbitrary Lagrangian Eulerian technique. To account for the lubrication resistant effects of the vapor cushion formed by the film-boiling evaporation, a separate vapor flow model is developed to simulate the pressure and velocity distribution along the vapor layer between the droplet and the surface. The temperature fields in all phases and the local evaporation rate on the droplet surface are determined by using a full field heat transfer model. Both the water and n-heptane droplets impacting on the solid wall with different Weber numbers are investigated. The comparisons of the simulation results with the experimental results reported in the literatures are made to substantiate the model presented in this study. Specially, the spreading and recoiling motions of the impacting droplets are reproduced accurately for a wide range of the Weber number. The oscillation of the thickness of the vapor layer and the temperature distribution across the interface are also calculated and compared favorably with the experimental results. As the Weber number increases, the extent of the droplet spreading increases, but the residence time of the droplet on the surface is almost unchanged. Compared to the saturated impacts, the subcooled impact yields a thinner vapor layer and a higher heat transfer rate.
Huda Mohammed J. Al-Thani
2004-04-01
Full Text Available We introduce and investigate flat semimodules and k-flat semimodules .We hope these concepts will have the same importance in semimodule theory as in the theory of rings and modules.
Kochenkov A G; Tonkonog V G
2011-01-01
Outcomes of experimental researches of the low-pressure adiabatic flow of the boiling liquid through two-dimensional Laval nozzles in a vacuum atmosphere were adduced.Requirements of critical conditions of flow were determined.Structural forms of a stream were investigated and their connection with crisis of flow was shown.It was established periodic non-stationary macrostructures of a stream which was stipulated by the rotational gear of origin of a vapor phase.
Sung, Yon Mi [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-dong, Kangnam-ku, Seoul 135-710 (Korea, Republic of); Department of Radiology, Gachon University Gil Hospital, 1198, Guwol-dong, Namdong-gu, Incheon 405-760 (Korea, Republic of); Chung, Myung Jin [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-dong, Kangnam-ku, Seoul 135-710 (Korea, Republic of)], E-mail: mj1.chung@samsung.com; Lee, Kyung Soo [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-dong, Kangnam-ku, Seoul 135-710 (Korea, Republic of); Choe, Bong-Keun [Department of Preventive Medicine, School of Medicine, Kyunghee University, Seoul (Korea, Republic of)
2010-04-15
Purpose: To compare observer performance with a flat-panel liquid crystal display (LCD) monitor and with a high-resolution gray-scale cathode ray tube (CRT) monitor in the detection of interstitial lung markings using a silicon flat-panel-detector direct radiography (DR) and storage phosphor computed radiography (CR) in a clinical setting. Materials and methods: We displayed 39 sets of posteroanterior chest radiographs from the patients who were suspected of interstitial lung disease. Each sets consisted of DR, CR and thin-section CT as the reference standard. Image identities were masked, randomly sorted, and displayed on both five mega pixel (2048 x 2560 x 8 bits) LCD and CRT monitors. Ten radiologists independently rated their confidence in detection for the presence of linear opacities in the four fields of the lungs; right upper, left upper, right lower, and left lower quadrant. Performance of a total 6240 (39 sets x 2 detector systems x 2 monitor system x 4 fields x 10 observers) observations was analyzed by multi-reader multi-case receiver operating characteristic (ROC) analysis. Differences between monitor systems in combinations of detector systems were compared using ANOVA and paired-samples t-test. Results: Area under curves (AUC) for the presence of linear opacities measured by ROC analysis was higher on the LCDs than CRTs without statistical significance (p = 0.082). AUC was significantly higher on the DR systems than CR systems (p = 0.006). AUC was significantly higher on the LCDs than CRTs for DR systems (p = 0.039) but not different for CR systems (p = 0.301). Conclusion: In clinical conditions, performance of the LCD monitor appears to be better for detecting interstitial lung markings when interfaced with DR systems.
du Toit, G J G; Ramphao, M C; Parco, V; Wentzel, M C; Ekama, G A
2007-01-01
The use of immersed membranes for solid-liquid separation in biological nutrient removal activated sludge (BNRAS) systems was investigated at lab scale. Two laboratory-scale BNR activated sludge systems were run in parallel, one a MBR system and the other a conventional system with secondary settling tanks. Both systems were in 3 reactor anaerobic, anoxic, aerobic UCT configurations. The systems were set up to have, as far as possible, identical design parameters such as reactor mass fractions, recycles and sludge age. Differences were the influent flow and total reactor volumes, and the higher reactor concentrations in the MBR system. The performances of the two systems were extensively monitored and compared to identify and quantify the influence of the membranes on system response. The MBR UCT system exhibited COD, FSA, TKN, TP and TSS removals that were consistently equivalent or superior to the conventional system. Better P removal in the MBR was attributed to lower observed P uptake in the anoxic zone. High nitrate loads to the anoxic reactor appeared to be the determining factor in stimulating P uptake. The MBR UCT system had a greater sludge production than the conventional system. This was partly attributable to the retention of all solids in the MBR reactor. For steady state design this increase is accommodated by increasing the influent unbiodegradable particulate COD fraction. Additionally an attempt was made to determine the Alpha values in the oxygen transfer rate. This paper briefly summarises and compares the results from both systems, and the conclusions that can be drawn from these results.
Doherty, Kevin Andrew
2017-01-01
'Flat pyramid' is a multi-channel video installation. The project employs appropriated promotional and instructional video from a defunct pyramid scheme as the source material for fictionalized reenactment. The footage primarily consists of presentation documentation, testimonial interviews, and product photography—throughout all of which cutting rarely occurs between takes. Perpetrators and victims are seen moving in and out of their promotional personas, inadvertently making their disquieti...
Palacios, E. [Universidad Politecnica de Madrid (Spain). Departamento de Mecanica Industrial; Nogueira, J.; Rodriguez, P.A.; Lecuona, A. [Universidad Carlos III de Madrid (Spain). Departamento de Ingenieria Termica y de Fluidos
2009-02-15
This work presents and characterizes the existence of two different regimes in the spreading and break-up of liquid flat-fan sheets when discharging in low-density atmospheres. The motivation of the study is the improvement on the absorption phenomena of lithium bromide aqueous solution when discharging in a 600-1,500 Pa water vapor environment. This corresponds to the absorber conditions in current absorption closed-cycle cooling machines. Despite this, the dimensionless characterization obtained has universal validity. The conditions that define the change in the break-up regime, the dimensionless sheet break-up length and the break-up time are given as a function of the parameters involved. Digital particle tracking velocimetry (PTV) has been applied to measure the velocity field and additional visualization techniques have been used to further characterize the break-up process. The experiments verify the existence of critical gas-to-liquid density and viscosity ratios below which gas to liquid interaction becomes negligible. The article also offers expressions that define their values as a function of the other dimensionless parameters. (orig.)
Yan Manman
2010-01-01
@@ Just as Thomas Fried man's famous book,The World Is Flat,if not completely flat,it is anyway tending to be shaped flat.January 1,2010 saw the formation of the China-ASEAN Free Trade Agreement(CAFTA),which was another historical event flattening majority of Asia continent for international trade.
Flat panel display - Impurity doping technology for flat panel displays
Suzuki, Toshiharu [Advanced Technology Planning, Sumitomo Eaton Nova Corporation, SBS Tower 9F, 10-1, Yoga 4-chome, Setagaya-ku, 158-0097 Tokyo (Japan)]. E-mail: suzuki_tsh@senova.co.jp
2005-08-01
Features of the flat panel displays (FPDs) such as liquid crystal display (LCD) and organic light emitting diode (OLED) display, etc. using low temperature poly-Si (LTPS) thin film transistors (TFTs) are briefly reviewed comparing with other FPDs. The requirements for fabricating TFTs used for high performance FPDs and system on glass (SoG) are addressed. This paper focuses on the impurity doping technology, which is one of the key technologies together with crystallization by laser annealing, formation of high quality gate insulator and gate-insulator/poly-Si interface. The issues to be solved in impurity doping technology for state of the art and future TFTs are clarified.
丁南庆
1994-01-01
The aim of this paper is to investigate relatively flat envelopes. A necessary and sufficient condition is given for a relatively-finitely presented module to have a (mono-morphic or epic) relatively flat envelope. Then those rings are characterized whose every relatively-finitely presented module has a relatively flat envelope which coincides with its in-jective envelope. Some known results are obtained as corollaries.
Pratas, Antonio
2014-01-01
This book contains practical, step-by-step tutorials along with plenty of explanation about designing your flat website. Each section is introduced sequentially, building up your web design skills and completing your website.Creating Flat Design Websites is ideal for you if you are starting on your web development journey, but this book will also benefit seasoned developers wanting to start developing in flat.
Strongly Gorenstein Flat Dimensions
Chun Xia ZHANG; Li Min WANG
2011-01-01
This article is concerned with the strongly Gorenstein flat dimensions of modules and rings.We show this dimension has nice properties when the ring is coherent,and extend the well-known Hilbert's syzygy theorem to the strongly Gorenstein flat dimensions of rings.Also,we investigate the strongly Gorenstein flat dimensions of direct products of rings and (almost)excellent extensions of rings.
Mayur, Manik; Amiroudine, Sakir; Lasseux, Didier; Chakraborty, Suman
2014-03-01
Electro-osmotic flows (EOF) have seen remarkable applications in lab-on-a-chip based microdevices owing to their lack of moving components, durability, and nondispersive nature of the flow profiles under specifically designed conditions. However, such flows may typically suffer from classical Faradaic artifacts like electrolysis of the solvent, which affects the flow rate control. Such a problem has been seen to be overcome by employing time periodic EOFs. Electric field induced transport of a conductive liquid is another nontrivial problem that requires careful study of interfacial dynamics in response to such an oscillatory flow actuation. The present study highlights the role of electric field generated Maxwell stress and free surface potential along with the electric double layer thickness and forcing frequency, toward influencing the interfacial transport and fluid flow in free-surface electro-osmosis under a periodically varying external electric field, in a semi-analytical formalism. Our results reveal interesting regimes over which the pertinent interfacial phenomena as well as bulk transport characteristics may be favorably tuned by employing time varying electrical fields.
缪泽群; 郑楷平; 肖桂凤; 宋韬
2014-01-01
目的 评价点阵二氧化碳激光联合液氮冷冻治疗扁平疣的临床疗效和安全性.方法 将83例扁平疣患者按治疗方法分为两组,观察组42例予点阵二氧化碳激光联合液氮冷冻治疗,对照组41例予液氮冷冻治疗,均10d为1个疗程,共治疗2个疗程.比较两组疗效、复发情况及不良反应.结果 观察组第1和2个疗程后痊愈率明显高于对照组[73.81％(31/42)比46.34％(19/41)和97.62％(41/42)比75.61％(31/41)],观察组复发率和不良反应发生率明显低于对照组[2.44％(1/41)比19.35％(6/31)和9.52％(4/42)比31.71％(13/41)],差异均有统计学意义(P＜ 0.05或＜ 0.01).结论 点阵二氧化碳激光联合液氮冷冻治疗扁平疣可明显提高痊愈率,降低复发率,而且安全.%Objective To evaluate the clinical efficacy and safety about carbon dioxide fractional laser combined with liquid nitrogen cryotherapy for flat warts.Methods Eighty-three patients with flat warts were divided into 2 groups according to the treatment method,42 patients in treatment group were treated by carbon dioxide fractional laser combined with liquid nitrogen cryotherapy,41 patients in control group were treated by liquid nitrogen cryotherapy alone.As a period for 10 days,2 groups were given 2 periods of treatment.The therapeutic effect,recurrence rate and adverse reaction were compared between 2 groups.Results The cure rates of 1-period and 2-period in treatment group were significantly higher than those in control group [73.81％(31/42) vs.46.34％(19/41) and 97.62％(41/42) vs.75.61％(31/41)],the recurrence rate and incidence of adverse reaction in treatment group were significantly lower than those in control group [2.44％(1/41) vs.19.35％(6/31) and 9.52％(4/42) vs.31.71％(13/41)],there were statistical differences (P ＜ 0.05 or ＜ 0.01).Conclusion Carbon dioxide fractional laser combined with liquid nitrogen cryotherapy for fiat warts is a safe and effective treatment with low
李嘉琪; 刁彦华; 赵耀华
2011-01-01
本文建立了新型平板热管相变蓄热装置的模型,利用数值模拟软件Fluent 6.2.16对以石蜡作为相变材料的融化过程进行了详实的研究,得到了相变材料的温度场和液相体积分数随时间的变化情况,分析了相变界面的变化规律.同时对不同翅片尺寸、不同传热温差下的传热情况进行了对比,得到了其对传热过程的影响规律.%In this paper, the software of Fluent 6. 2. 16 was used to establish the model of phase change thermal storage equipment with novel flat heat pipe, and the melt process was simulated taking paraffin wax as the phase change material. Based on the simulation,the variation trends of temperature field,liquid volume fraction and interface of phase change were discussed. Furthermore, the heat transfer process was compared under different size of fins and different temperature differences, hence the influence rules of these parameters on heat transfer process were achieved.
Alrashed, Mohammed
2017-05-26
Disclosed are various embodiments for connectors used with electronic devices, such as input and/or output ports to connect peripheral equipment or accessories. More specifically, various flat-port are provided that can be used in place of standard connectors including, but not limited to, audio jacks and Universal Serial Bus (USB) ports. The flat-port connectors are an alternate connection design to replace the traditional receptacle port (female-port), making the device more sealed creation more dust and water resistant. It is unique in the way of using the outer surfaces of the device for the electrical connection between the ports. Flat-port design can allow the manufacture of extremely thin devices by eliminating the side ports slots that take a lot of space and contribute to the increase thickness of the device. The flat-port receptacle improves the overall appearance of the device and makes it more resistant to dust and water.
Individual energy savings for individual flats in blocks of flats
Nielsen, Anker; Rose, Jørgen
2014-01-01
It is well known that similar flats in a block do not have the same energy demand. Part of the explanation for this is the location of the flat in the building, e.g. on the top floor, at the house end or in the middle of the building. It is possible to take this into account when the heating bill...... is distributed on the individual flats. Today, most blocks of flats have individual heat meters to save energy and to ensure a fair distribution of the cost. If all flats have the same indoor temperature, the distribution is correct. In practice, the inhabitants of the different flats maintain different indoor...
Parallel artificial liquid membrane extraction
Gjelstad, Astrid; Rasmussen, Knut Einar; Parmer, Marthe Petrine
2013-01-01
This paper reports development of a new approach towards analytical liquid-liquid-liquid membrane extraction termed parallel artificial liquid membrane extraction. A donor plate and acceptor plate create a sandwich, in which each sample (human plasma) and acceptor solution is separated by an arti...... by an artificial liquid membrane. Parallel artificial liquid membrane extraction is a modification of hollow-fiber liquid-phase microextraction, where the hollow fibers are replaced by flat membranes in a 96-well plate format....
Xu, Jinzhong
1996-01-01
Since the injective envelope and projective cover were defined by Eckmann and Bas in the 1960s, they have had great influence on the development of homological algebra, ring theory and module theory. In the 1980s, Enochs introduced the flat cover and conjectured that every module has such a cover over any ring. This book provides the uniform methods and systematic treatment to study general envelopes and covers with the emphasis on the existence of flat cover. It shows that Enochs' conjecture is true for a large variety of interesting rings, and then presents the applications of the results. Readers with reasonable knowledge in rings and modules will not have difficulty in reading this book. It is suitable as a reference book and textbook for researchers and graduate students who have an interest in this field.
无
2005-01-01
欢迎来到这期的光盘介绍。本月的附刊光盘中，除了每月的精彩教程外，您可在光盘中找到15张由Flat Earth友情提供的库存图片。当然还有Twixtor和最新的Acrobat Reader 7。
REVIEW OF PERFORMANCE AND ANALYSIS ISI FLAT PLATE COLLECTOR WITH MODIFIED FLAT PLATE COLLECTOR
MR.Y.Y.NANDURKAR
2012-03-01
Full Text Available The market of solar water heater of natural circulation type (thermo-siphon is fast growing in India. Initial cost of the solar water heater system at present is high because of store type design. It is necessary to make the product more popular by reducing the cost. This is possible by reducing area of liquid flat plate collector by increasing tube diameter and reducing riser length. Hence it is essential to make solar water heater in affordable range of the general public class. Present work is based on review of comparative performance and analysis of ISI flat plate collector with modified flat plat collector. The paper will be helpful for those who are working in the area of solar water heating system and their use in domestic areas.
Flat conductor cable commercialization project
Hogarth, P.; Wadsworth, E.
1977-01-01
An undercarpet flat conductor cable and a baseboard flat conductor cable system were studied for commercialization. The undercarpet system is designed for use in office and commercial buildings. It employs a flat power cable, protected by a grounded metal shield, that terminates in receptacles mounted on the floor. It is designed to interface with a flat conductor cable telephone system. The baseboard system consists of a flat power cable mounted in a plastic raceway; both the raceway and the receptacles are mounted on the surface of the baseboard. It is designed primarily for use in residential buildings, particularly for renovation and concrete and masonry construction.
Piecewise flat gravitational waves
Van de Meent, Maarten, E-mail: M.vandeMeent@uu.nl [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, PO Box 80.195, 3508 TD Utrecht (Netherlands)
2011-04-07
We examine the continuum limit of the piecewise flat locally finite gravity model introduced by 't Hooft. In the linear weak field limit, we find the energy-momentum tensor and metric perturbation of an arbitrary configuration of defects. The energy-momentum turns out to be restricted to satisfy certain conditions. The metric perturbation is mostly fixed by the energy-momentum except for its lightlike modes which reproduce linear gravitational waves, despite no such waves being present at the microscopic level.
Vukašinović Zoran
2009-01-01
Full Text Available The authors describe flatfoot, as one of very frequent deformities in everyday medical practice. A special condition of the deformity associated with a calcaneal valgus position and complicated by a knee valgus position (as a consequence of non-treatment is described. Also, the precise anatomy of the longitudinal foot arches (medial and lateral, definition and classification of the deformity, clinical findings and therapeutic protocols are proposed. The authors especially emphasise that the need for having extensive knowledge on the differences between a flexible and rigid flatfoot, having in mind that the treatment of flexible flat foot is usually not necessary, while the treatment of rigid flatfoot is usually unavoidable.
Cristian Încalţărău
2010-06-01
Full Text Available Globalization became more and more prominent during the last decades. There is no way to argue that globalization led to more interconnected economies, facilitating the communication and the collaboration around the world. But where is this going? Doesglobalization mean uniformity or diversity? As the world begins to resemble more, the people are trying to distinguish between them more, which can exacerbate nationalistic feeling. Friedman argues that globalization made the world smaller and flatter, allowing all countries to take chance of the available opportunities equally. But is this really true? Although politic and cultural factors can stand in front of a really flat world, what is the key for Chinese and Indian success and which are theirs perspectives?
Mei, Shengtao; Hussain, Sajid; Huang, Kun; Ling, Xiaohui; Siew, Shawn Yohanes; Liu, Hong; Teng, Jinghua; Danner, Aaron; Qiu, Cheng-Wei
2016-01-01
Compact and miniaturized devices with flexible functionalities are always highly demanded in optical integrated systems. Plasmonic nanosieve has been successfully harnessed as an ultrathin flat platform for complex manipulation of light, including holography, vortex generation and non-linear processes. Compared with most of reported single-functional devices, multi-functional nanosieves might find more complex and novel applications across nano-photonics, optics and nanotechnology. Here, we experimentally demonstrate a promising roadmap for nanosieve-based helical devices, which achieves full manipulations of optical vortices, including its generation, hybridization, spatial multiplexing, focusing and non-diffraction propagation etc., by controlling the geometric phase of spin light via over 121 thousands of spatially-rotated nano-sieves. Thanks to such spin-conversion nanosieve helical elements, it is no longer necessary to employ the conventional two-beam interferometric measurement to characterize optical ...
Figueroa-O'Farrill, J M
1999-01-01
Certain supergravity solutions (including domain walls and the magnetic fivebrane) have recently been generalised by Brecher and Perry by relaxing the condition that the brane worldvolume be flat. In this way they obtain examples in which the brane worldvolume is a static spacetime admitting parallel spinors. In this note we simply point out that the restriction to static spacetimes is unnecessary, and in this way exhibit solutions where the brane worldvolume is an indecomposable Ricci-flat lorentzian manifold admitting parallel spinors. We discuss more Ricci-flat fivebranes and domain walls, as well as new Ricci-flat D3-branes.
Development of a flat membrane based device for electromembrane extraction
Huang, Chuixiu; Eibak, Lars Erik Eng; Gjelstad, Astrid
2014-01-01
In this work, a single-well electromembrane extraction (EME) device was developed based on a thin (100μm) and flat porous membrane of polypropylene supporting a liquid membrane. The new EME device was operated with a relatively large acceptor solution volume to promote a high recovery. Using this...
聂元梅; 董心亚; 燕群
2014-01-01
Objective To observe the clinical efficacy of thymopeptide enteric-coated capsules combined with liquid nitrogen cryotherapy in the treatment of flat warts. Methods 92 patients with flat warts were divided into two groups randomly. The control group was given thymopeptide enteric-coated capsules 10mg, orally, 3 times a day, and recombinant human interferon α-2b gel applied to the affected area twice a day, the 0.1% tretinoin cream applied to the affected area once every night before sleeping. The treatment group was given thymopeptide enteric-coated capsules 10mg, 3 times a day, orally, and at the same time, they were given liquid nitrogen cryotherapy. The two groups were given the course of treatment of two months. Results The effective rate was 93.5% in the treatment group, and that was 65.2% in the control group. The difference between the two groups in effective rate was statistically significant (P<0.05). Conclusion The curative effect of thymopeptide enteric-coated capsules combined with liquid nitrogen cryotherapy on flat warts is remarkable.%目的：探讨胸腺肽肠溶胶囊联合液氮冷冻治疗扁平疣的疗效。方法将92例扁平疣患者随机分为两组，对照组口服胸腺肽肠溶胶囊10 mg,tid,重组人干扰素α-2b凝胶外用bid，0.1%维A酸软膏外用睡前1次。治疗组口服胸腺肽肠溶胶囊10mg,tid，同时给于液氮冷冻治疗。两组疗程均为2个月。结果治疗组有效率为93.5%，对照组为65.2%。两组比较差异有统计学意义（P<0.05)。结论胸腺肽肠溶胶囊联合液氮冷冻治疗扁平疣疗效确切。
Irritated Method for Flat warts
LiBingxu
2004-01-01
Summary Background The relation between spontaneous regression of Flat warts and T cells depended immunity was confirmed. Cells immunity against HPV was induced by presenting of HPV related antigens, and thrived by cytokine and some chemistry agent. So how to make HPV which incubated in keratinocyte to present PHV antigens and keratinocyte to secret cytokine or chemistry agents should be a pursuance for dermatologist who are looking for a efficient method to deal with flat warts. Present research had exhibited inflammable agents can induce dermatitis when apply to the skin surface, so it might bring flat warts to spontaneous regression. Objective To observe the effectiveness of irritant drugs on flat warts, and at same time to understand more on the mechanism of the regression. Methods Compared with Control we treat 88 case of flat warts with retinoid gel or 3% hydrogen peroxide solution plus 5 % salicylic acid cream (HPSC). Results Both retinoid gel and HPSC reveal significant effect on flat warts. Conclusion Retinoid gel or SPHC was effective on the treatment of flat warts. The possible explanation for this is the drugs when put on the skin will induce dermatitis and dissolve or denude keratin.
Measurements of Flat-Plate Milk Coolers
Vlastimil Nejtek
2014-01-01
Full Text Available Measuring in laboratory conditions was performed with the aim to collect a sufficient quantity of measured data for the qualified application of flat-plate coolers in measuring under real operating conditions. The cooling water tank was filled with tap water; the second tank was filled with water at a temperature equivalent to freshly milked milk. At the same time, pumps were activated that delivered the liquids into the flat-plate cooler where heat energy was exchanged between the two media. Two containers for receiving the run-out liquid were placed on the outputs from the cooler; here, temperature was measured with electronic thermometer and volume was measured with calibrated graduated cylinder. Flow rate was regulated both on the side of the cooling fluid and on the side of the cooled liquid by means of a throttle valve. The measurements of regulated flow-rates were repeated several times and the final values were calculated using arithmetic average. To calculate the temperature coefficient and the amount of brought-in and let-out heat, the volume measured in litres was converted to weight unit. The measured values show that the volume of exchanged heat per weight unit increases with the decreasing flow-rate. With the increasing flow-rate on the throttled side, the flow-rate increases on the side without the throttle valve. This phenomenon is caused by pressure increase during throttling and by the consequent increase of the diameter of channels in the cooler at the expense of the opposite channels of the non-throttled part of the circuit. If the pressure is reduced, there is a pressure decrease on the external walls of opposite channels and the flow-rate increases again. This feature could be utilised in practice: a pressure regulator on one side could regulate the flow-rate on the other side. The operating measurement was carried out on the basis of the results of laboratory measurements. The objective was to determine to what extent the
Flats: Preliminary WFC Data and Plans for Flight Flats
Bohlin, R. C.; Hartig, G.; Tsvetanov, Z.
2000-10-01
The ACS WFC pixel-to-pixel P-flats with the build-3 detector repeat over a three month time span to a precision of better than 0.1% rms. The shape of the low frequency Lflat field varies with wavelength, where the ratio of the F435W/F814W L-flats differs from unity by - 10% in two patches near opposite corners of the field of view. At ~0.5%, the high frequency pixel-to-pixel structure in the WFC P-flats is about half that of the HRC build-2 and does not increase as much toward shorter wavelengths as the HRC build-2 with the Lesser coating. The amplitude of the fringes for continuum illumination is less than 1%, even in the narrow band ramp filters, while the fringing in monochromatic light is - 10% at 9300 Å. The goals of the laboratory WFC and HRC flat field program are to obtain the set of external flats that fully populates the pipeline database and to archive a baseline of high S/N internal flats for tracking post-launch changes.
Is classical flat Kasner spacetime flat in quantum gravity?
Singh, Parampreet
2016-01-01
Quantum nature of classical flat Kasner spacetime is studied using effective spacetime description in loop quantum cosmology. We find that even though the spacetime curvature vanishes at the classical level, non-trivial quantum gravitational effects can arise. For the standard loop quantization of Bianchi-I spacetime, which uniquely yields universal bounds on expansion and shear scalars and results in a generic resolution of strong singularities, we find that a flat Kasner metric is not a physical solution of the effective spacetime description, except in a limit. The lack of a flat Kasner metric at the quantum level results from a novel feature of the loop quantum Bianchi-I spacetime: quantum geometry induces non-vanishing spacetime curvature components, making it not Ricci flat even when no matter is present. The non-curvature singularity of the classical flat Kasner spacetime is avoided, and the effective spacetime transits from a flat Kasner spacetime in asymptotic future, to a Minkowski spacetime in asym...
Estrada, N. [Instituto de Fisica, Universidad Autonoma de San Luis Potosi (Mexico); Engelfried, J. [Instituto de Fisica, Universidad Autonoma de San Luis Potosi (Mexico)]. E-mail: jurgen@ifisica.uaslp.mx; Morelos, A. [Instituto de Fisica, Universidad Autonoma de San Luis Potosi (Mexico)
2005-11-11
One of the RICHes in the velocity spectrometers of the proposed CKM experiment requires a flat mirror, situated in the high intensity kaon beam. To reduce the interaction background for the experiment, this mirror has to be as thin as possible. First glass prototypes were produced in Mexico. To test the surface quality of these prototypes, we extended the Ronchi method so flat mirrors can also be tested. We present the methods and report on results of our measurements.
The Fallacies of Flatness: Thomas Friedman's "The World Is Flat"
Abowitz, Kathleen Knight; Roberts, Jay
2007-01-01
Thomas Friedman's best-selling "The World is Flat" has exerted much influence in the west by providing both an accessible analysis of globalization and its economic and social effects, and a powerful cultural metaphor for globalization. In this review, we more closely examine Friedman's notion of the social contract, the moral center of his…
Nonlocal gravity: Conformally flat spacetimes
Bini, Donato
2016-01-01
The field equations of the recent nonlocal generalization of Einstein's theory of gravitation are presented in a form that is reminiscent of general relativity. The implications of the nonlocal field equations are studied in the case of conformally flat spacetimes. Even in this simple case, the field equations are intractable. Therefore, to gain insight into the nature of these equations, we investigate the structure of nonlocal gravity in two-dimensional spacetimes. While any smooth 2D spacetime is conformally flat and satisfies Einstein's field equations, only a subset containing either a Killing vector or a homothetic Killing vector can satisfy the field equations of nonlocal gravity.
Chemically induced electric field: flat band potential engineering
Bak, T.; Guo, Z.; Li, W.; Atanacio, A. J.; Nowotny, J.
2012-10-01
The present work considers engineering of the flat band potential, FBP, of metal oxides in a controlled manner. The aim is to minimise the energy losses related to recombination. The related experimental approaches include imposition of a chemically-induced electric field using the phenomena of segregation, diffusion and the formation of multilayer systems. This paper considers several basic phenomena that allow the modification of the surface charge and the space charge at the gas/solid and solid/liquid interfaces.
Flat space physics from holography
Bousso, R
2004-01-01
We point out that aspects of quantum mechanics can be derived from the holographic principle, using only a perturbative limit of classical general relativity. In flat space, the covariant entropy bound reduces to the Bekenstein bound. The latter does not contain Newton's constant and cannot operate via gravitational backreaction. Instead, it is protected by - and in this sense, predicts - the Heisenberg uncertainty principle
The complexity of flat origami
Bern, M. [Xerox, Palo Alto, CA (United States); Hayes, B. [ParcPlace-Digitalk, Inc., Sunnyvale, CA (United States)
1996-12-31
We study a basic problem in mathematical origami: determine if a given crease pattern can be folded to a flat origami. We show that assigning mountain and valley folds is NP-hard. We also show that determining a suitable overlap order for flaps is NP-hard, even assuming a valid mountain and valley assignment.
Line bundles and flat connections
INDRANIL BISWAS; GEORG SCHUMACHER
2017-06-01
We prove that there are cocompact lattices $\\Gamma$ in $\\rm SL(2,\\mathbb C)$ with the property that there are holomorphic line bundles $L$ on $\\rm SL(2,\\mathbb C)/ \\Gamma$ with $c_{1}(L) = 0$ such that $L$ does not admit any unitary flat connection.
Automatic Flatness Control of Cold Rolling Mill
Anbe, Yoshiharu; Sekiguchi, Kunio
One of the subjects of cold rolling is a flatness of the rolled strip. Conventionally, measured strip flatness was approximated by polynomial (2th, 4th, 6th) equation across the entire strip width. This made it difficult to deal with desired loose edge or any desired flatness across the entire strip width. Also conventional flatness control was done for the entire strip width, so if there is a different flatness error among drive side and work side, conventional flatness control can not control properly. We propose independent strip flatness control among drive side and work side, and also automatic flatness control (AFC) system with arbitrary desired strip flatness. Also some applied results to cold mill are shown.
无
2010-01-01
菲亚特选在柏林举行的“面包与黄油（Bread＆Butter）”青年时尚秀中发布了500柴油版车型。这款车型首先推出的是黑色和绿色车身颜色，共限量1万辆，目前已有6000辆被售出。现在，它又追加了1款车身颜色“午夜蓝”，菲亚特选择这款颜色，是因为它很接近牛仔裤的颜色，更容易吸引年轻的消费者。
Laser illuminated flat panel display
Veligdan, J.T.
1995-12-31
A 10 inch laser illuminated flat panel Planar Optic Display (POD) screen has been constructed and tested. This POD screen technology is an entirely new concept in display technology. Although the initial display is flat and made of glass, this technology lends itself to applications where a plastic display might be wrapped around the viewer. The display screen is comprised of hundreds of planar optical waveguides where each glass waveguide represents a vertical line of resolution. A black cladding layer, having a lower index of refraction, is placed between each waveguide layer. Since the cladding makes the screen surface black, the contrast is high. The prototype display is 9 inches wide by 5 inches high and approximately I inch thick. A 3 milliwatt HeNe laser is used as the illumination source and a vector scanning technique is employed.
Parallel spinors on flat manifolds
Sadowski, Michał
2006-05-01
Let p(M) be the dimension of the vector space of parallel spinors on a closed spin manifold M. We prove that every finite group G is the holonomy group of a closed flat spin manifold M(G) such that p(M(G))>0. If the holonomy group Hol(M) of M is cyclic, then we give an explicit formula for p(M) another than that given in [R.J. Miatello, R.A. Podesta, The spectrum of twisted Dirac operators on compact flat manifolds, Trans. Am. Math. Soc., in press]. We answer the question when p(M)>0 if Hol(M) is a cyclic group of prime order or dimM≤4.
Graphene folding on flat substrates
Chen, Xiaoming; Zhao, Yadong; Ke, Changhong, E-mail: cke@binghamton.edu [Department of Mechanical Engineering, State University of New York at Binghamton, Binghamton, New York 13902 (United States); Zhang, Liuyang; Wang, Xianqiao [College of Engineering, University of Georgia, Athens, Georgia 30602 (United States)
2014-10-28
We present a combined experimental-theoretical study of graphene folding on flat substrates. The structure and deformation of the folded graphene sheet are experimentally characterized by atomic force microscopy. The local graphene folding behaviors are interpreted based on nonlinear continuum mechanics modeling and molecular dynamics simulations. Our study on self-folding of a trilayer graphene sheet reports a bending stiffness of about 6.57 eV, which is about four times the reported values for monolayer graphene. Our results reveal that an intriguing free sliding phenomenon occurs at the interlayer van der Waals interfaces during the graphene folding process. This work demonstrates that it is a plausible venue to quantify the bending stiffness of graphene based on its self-folding conformation on flat substrates. The findings reported in this work are useful to a better understanding of the mechanical properties of graphene and in the pursuit of its applications.
Flat heat pipe design, construction, and analysis
Voegler, G.; Boughey, B.; Cerza, M.; Lindler, K.W.
1999-08-02
This paper details the design, construction and partial analysis of a low temperature flat heat pipe in order to determine the feasibility of implementing flat heat pipes into thermophotovoltaic (TPV) energy conversion systems.
García-Compeán, Hugo; Martínez-Merino, Aldo; Santos-Silva, Roberto
2013-01-01
By wrapping D3-branes over 3-cycles on a Half-flat manifold we construct an effective supersymmetric Black Hole in the N=2 low-energy theory in four-dimensions. Specifically we find that the torsion cycles present in a half-flat compactification, corresponding to the mirror symmetric image of electric NS flux on a Calabi-Yau manifold, manifest in the black hole physics as quantum hair. We compute the electric and magnetic charges related to the quantum hair, and also the mass contribution to the effective black hole. We find that by wrapping a number of D3-branes equal to the order of the discrete group associated to the torsional part of the half-flat homology, the effective charge and mass terms vanishes. We compute the variation of entropy and the corresponding temperature associated with the lost of the quantum hair. We also comment on the equivalence between canceling Freed-Witten anomalies and the assumption of self-duality for the five-form field strength. Finally from a K-theoretical perspective, we c...
Flat colon polyps: what should radiologists know?
Ignjatovic, A. [Intestinal Imaging Centre, St Mark' s Hospital, Harrow, Middlesex (United Kingdom); Burling, D., E-mail: burlingdavid@yahoo.co.u [Intestinal Imaging Centre, St Mark' s Hospital, Harrow, Middlesex (United Kingdom); Ilangovan, R.; Clark, S.K.; Taylor, S.A.; East, J.E.; Saunders, B.P. [Intestinal Imaging Centre, St Mark' s Hospital, Harrow, Middlesex (United Kingdom)
2010-12-15
With the recent publication of international computed tomography (CT) colonography standards, which aim to improve quality of examinations, this review informs radiologists about the significance of flat polyps (adenomas and hyperplastic polyps) in colorectal cancer pathways. We describe flat polyp classification systems and propose how flat polyps should be reported to ensure patient management strategies are based on polyp morphology as well as size. Indeed, consistency when describing flat polyps is of increasing importance given the strengthening links between CT colonography and endoscopy.
A diagram for defined solar radiation absorbed per unit area of flat plate solar collectors
Tekin, Y.; Altuntop, N. [Erciyes University, Dept. of Mechanical Engineering (Turkey); Cengel, Y.A. [Nevada Reno University, Dept. of Mechanical Engineering, NV (United States); Cengel, Y.A. [Nevada University, Dept. Mechanical Engineering, Reno, NV (United States)
2000-07-01
In Erciyes University, the Solar House (28.75 m{sup 2}) is heated from the floor by using flat plate liquid solar collectors. Required solar radiation for heating and heat losses are calculated. In this work, the required calculations for Erciyes Solar House were generalized and required calculation were done to evaluate absorbed solar radiation per unit surface of the flat plate liquid collector. At the end, three generalized diagrams for nine different months are obtained using obtained numerical values. The goal of preparing diagrams is to determine absorbed solar radiation per unit surface area of flat plate liquid collector at any instant at any latitude, In this work, the diagram is explained by means of sample calculations for November. This diagram was prepared to find out absorbed solar radiation per unit area of black surface collector by means obtained equations. With this diagram, all instant solar radiation can be evaluated in 19 steps. (authors)
An extension to flat band ferromagnetism
Gulacsi, M.; Kovacs, G.; Gulacsi, Z.
2014-11-01
From flat band ferromagnetism, we learned that the lowest energy half-filled flat band gives always ferromagnetism if the localized Wannier states on the flat band satisfy the connectivity condition. If the connectivity conditions are not satisfied, ferromagnetism does not appear. We show that this is not always the case namely, we show that ferromagnetism due to flat bands can appear even if the connectivity condition does not hold due to a peculiar behavior of the band situated just above the flat band.
Length spectra and degeneration of flat metrics
Duchin, Moon; Rafi, Kasra
2009-01-01
In this paper we consider flat metrics (semi-translation structures) on surfaces of finite type. There are two main results. The first is a complete description of when a set of simple closed curves is spectrally rigid, that is, when the length vector determines a metric among the class of flat metrics. Secondly, we give an embedding into the space of geodesic currents and use this to get a boundary for the space of flat metrics. The geometric interpretation is that flat metrics degenerate to "mixed structures" on the surface: part flat metric and part measured foliation.
Non-Perturbative Flat Direction Decay
Basboll, A; Riva, F; West, S M; Basboll, Anders; Maybury, David; Riva, Francesco; West, Stephen M.
2007-01-01
We argue that supersymmetric flat direction vevs can decay non-perturbatively via preheating. Considering the case of a single flat direction, we explicitly calculate the scalar potential in the unitary gauge for a U(1) theory and show that the mass matrix for excitations around the flat direction has non-diagonal entries which vary with the phase of the flat direction vev. Furthermore, this mass matrix has 2 zero eigenvalues (associated with the excitations along the flat direction) whose eigenstates change with time. We show that these 2 light degrees of freedom are produced copiously in the non-perturbative decay of the flat direction vev. We also comment on the application of these results to the MSSM flat direction H_uL.
Brule, Stephane; Guenneau, Sebastien
2016-01-01
A prerequisite for achieving seismic invisibility is to demonstrate the ability of civil engineers to control seismic waves with artificially structured soils. We carry out large-scale field tests with a structured soil made of a grid consisting of cylindrical and vertical holes in the ground and a low frequency artificial source (< 10 Hz). This allows the identification of a distribution of energy inside the grid, which can be interpreted as the consequence of an effective negative refraction index. Such a flat lens reminiscent of what Veselago and Pendry envisioned for light opens avenues in seismic metamaterials to counteract the most devastating components of seismic signals.
Flat coalgebraic fixed point logics
Schröder, Lutz
2010-01-01
Fixed point logics have a wide range of applications in computer science, in particular in artificial intelligence and concurrency. The most expressive logics of this type are the mu-calculus and its relatives. However, popular fixed point logics tend to trade expressivity for simplicity and readability, and in fact often live within the single variable fragment of the mu-calculus. The family of such flat fixed point logics includes, e.g., CTL, the *-nesting-free fragment of PDL, and the logic of common knowledge. Here, we extend this notion to the generic semantic framework of coalgebraic logic, thus covering a wide range of logics beyond the standard mu-calculus including, e.g., flat fragments of the graded mu-calculus and the alternating-time mu-calculus (such as ATL), as well as probabilistic and monotone fixed point logics. Our main results are completeness of the Kozen-Park axiomatization and a timed-out tableaux method that matches EXPTIME upper bounds inherited from the coalgebraic mu-calculus but avo...
Polyurethane adhesives in flat roofs
Bogárová Markéta
2017-01-01
Full Text Available It is necessary to stabilize individual layers of flat roofs, mainly because of wind suction. Apart from anchoring and surcharge, these layers can be secured by bonding. At present gluing is an indispensable and widely used stabilization method. On our market we can found many types of adhesives, most widely used are based on polyurethane. This paper focuses on problematic about stabilization thermal insulation from expanded polystyrene to vapor barrier from bitumen. One of the main issues is to calculate the exact amount of adhesive, which is required to guarantee the resistance against wind suction. In this problematic we can not find help neither in technical data sheets provided by the manufactures. Some of these data sheets contain at least information about amount of adhesive depending on location in roof plane and building height, but they do not specify the strength of such connection. It was therefore resorted to select several representatives polyurethane adhesives and their subsequent testing on specimens simulating the flat roof segment. The paper described the test methodology and results for two types of polyurethane adhesives.
CERN PhotoLab
1978-01-01
The picture shows a "Flat-Fish" vacuum chamber being prepared in the ISR workshop for testing prior to installation in the Split Field Magnet (SFM) at intersection I4. The two shells of each part were hydroformed from 0.15 mm thick inconel 718 sheet (with end parts in inconel 600 for easier manual welding to the arms) and welded toghether with two strips which were attached by means of thin stainless steel sheets to the Split Field Magnet poles in order to take the vertical component of the atmospheric pressure force. This was the thinnest vacuum chamber ever made for the ISR. Inconel material was chosen for its high elastic modulus and strenght at chamber bake-out temperature. In this picture the thin sheets transferring the vertical component of the atmosferic pressure force are attached to a support frame for testing. See also 7712182, 7712179.
Rowlinson, J S; Baldwin, J E; Buckingham, A D; Danishefsky, S
2013-01-01
Liquids and Liquid Mixtures, Third Edition explores the equilibrium properties of liquids and liquid mixtures and relates them to the properties of the constituent molecules using the methods of statistical thermodynamics. Topics covered include the critical state, fluid mixtures at high pressures, and the statistical thermodynamics of fluids and mixtures. This book consists of eight chapters and begins with an overview of the liquid state and the thermodynamic properties of liquids and liquid mixtures, including vapor pressure and heat capacities. The discussion then turns to the thermodynami
Flat laminated microbial mat communities
Franks, Jonathan; Stolz, John F.
2009-10-01
Flat laminated microbial mats are complex microbial ecosystems that inhabit a wide range of environments (e.g., caves, iron springs, thermal springs and pools, salt marshes, hypersaline ponds and lagoons, methane and petroleum seeps, sea mounts, deep sea vents, arctic dry valleys). Their community structure is defined by physical (e.g., light quantity and quality, temperature, density and pressure) and chemical (e.g., oxygen, oxidation/reduction potential, salinity, pH, available electron acceptors and donors, chemical species) parameters as well as species interactions. The main primary producers may be photoautotrophs (e.g., cyanobacteria, purple phototrophs, green phototrophs) or chemolithoautophs (e.g., colorless sulfur oxidizing bacteria). Anaerobic phototrophy may predominate in organic rich environments that support high rates of respiration. These communities are dynamic systems exhibiting both spatial and temporal heterogeneity. They are characterized by steep gradients with microenvironments on the submillimeter scale. Diel oscillations in the physical-chemical profile (e.g., oxygen, hydrogen sulfide, pH) and species distribution are typical for phototroph-dominated communities. Flat laminated microbial mats are often sites of robust biogeochemical cycling. In addition to well-established modes of metabolism for phototrophy (oxygenic and non-oxygenic), respiration (both aerobic and anaerobic), and fermentation, novel energetic pathways have been discovered (e.g., nitrate reduction couple to the oxidation of ammonia, sulfur, or arsenite). The application of culture-independent techniques (e.g., 16S rRNA clonal libraries, metagenomics), continue to expand our understanding of species composition and metabolic functions of these complex ecosystems.
Representability of Hom Implies Flatness
Nitin Nitsure
2004-02-01
Let be a projective scheme over a noetherian base scheme , and let $\\mathcal{F}$ be a coherent sheaf on . For any coherent sheaf $\\mathcal{E}$ on , consider the set-valued contravariant functor $\\hom_{(\\mathcal{E},\\mathcal{F})}$ on -schemes, defined by $\\hom_{(\\mathcal{E},\\mathcal{F})}(T)=\\mathrm{Hom}(\\mathcal{E}_T,\\mathcal{F}_T)$ where $\\mathcal{E}_T$ and $\\mathcal{F}_T$ are the pull-backs of $\\mathcal{E}$ and $\\mathcal{F}$ to $X_T=X×_s T$. A basic result of Grothendieck ([EGA], III 7.7.9) says that if $\\mathcal{F}$ is flat over then $\\hom_{(\\mathcal{E},\\mathcal{F})}$ is representable for all $\\mathcal{E}$. We prove the converse of the above, in fact, we show that if is a relatively ample line bundle on over such that the functor $\\hom_{(L^{-n},\\mathcal{F})}$ is representable for infinitely many positive integers , then $\\mathcal{F}$ is flat over . As a corollary, taking $X=S$, it follows that if $\\mathcal{F}$ is a coherent sheaf on then the functor $T\\mapsto H^0(T,\\mathcal{F}_T)$ on the category of -schemes is representable if and only if $\\mathcal{F}$ is locally free on . This answers a question posed by Angelo Vistoli. The techniques we use involve the proof of flattening stratification, together with the methods used in proving the author's earlier result (see [N1]) that the automorphism group functor of a coherent sheaf on is representable if and only if the sheaf is locally free.
A dynamic performance simulation model of flat-plate solar collectors for a heat pump system
Arinze, E.A.; Schoenau, G.J.; Sokhansanj, S. (Saskatchewan Univ., Saskatoon, SK (Canada). College of Engineering); Adefila, S.S.; Mumah, S.M. (Ahmadu Bello Univ., Zaria (Nigeria). Dept. of Chemical Engineering)
1993-01-01
Flat-plate collectors are inherently exposed to time-varying meteorological and system parameters. Thus, dynamic modeling, rather than the commonly used steady-state models, is a more accurate approach for the design and performance evaluation of flat-plate solar collectors. The dynamic model presented in this study describes the fluid, plate and cover temperatures of the collector by three different differential equations. Taylor series expansion and the Runge-Kutta method are used in the solution of the differential equations. The accuracy of the dynamic model was tested by comparing the results predicted by the model with experimental performance data obtained for a liquid-cooled flat-plate solar collector with a corrugated transparent fiberglass cover. The predicted results by the dynamic model agreed favorably with the measured experimental data for the flat-plate solar collector. Experimentally determined collector temperatures varied by a maximum of [+-]3[sup o]C from values predicted by the model. (Author)
Zhongmin WAN; Wei LIU; Zhaoqing ZHENG; A. Nakayama
2007-01-01
An overall two-dimensional numerical model of the miniature flat plate capillary pumped loop (CPL) evaporator is developed to describe the liquid and vapor flow, heat transfer and phase change in the porous wick structure,liquid flow and heat transfer in the compensation cavity and heat transfer in the vapor grooves and metallic wall.The entire evaporator is solved with SIMPLE algorithm as a conjugate problem. The effect of heat conduction of metallic side wall on the performance of miniature flat plate CPL evaporator is analyzed, and side wall effect heat transfer limit is introduced to estimate the performance of evaporator. The shape and location of vapor-liquid interface inside the wick are calculated and the influences of applied heat flux, liquid subcooling, wick material and metallic wall material on the evaporator performance are investigated in detail. The numerical results obtained are useful for the miniature flat plate evaporator performance optimization and design of CPL.
NONE
1998-03-01
The bibliography contains citations concerning the design and thermal efficiency of air and liquid type flat plate solar collectors. Topics include convection characteristics, methods to reduce heat loss, optical coatings, and corrosion prevention. Emphasis is on research and modeling. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)
NONE
1997-05-01
The bibliography contains citations concerning the design and thermal efficiency of air and liquid type flat plate solar collectors. Topics include convection characteristics, methods to reduce heat loss, optical coatings, and corrosion prevention. Emphasis is on research and modeling. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)
Flat plate solar collector design and performance. Citations from the NTIS data base
Hundemann, A. S.
1980-09-01
Federally funded research on the design and thermal efficiency of air and liquid type flat plate collectors is discussed. Topic areas cover convection characteristics, methods to reduce heat loss, optical coatings, and corrosion control. Emphasis of the bibliography is on basic research studies. This updated bibliography contains 196 citations, 36 of which are new entries to the previous edition.
Spills on Flat Inclined Pavements
Simmons, Carver S.; Keller, Jason M.; Hylden, Jeff L.
2004-03-01
This report describes the general spill phenomenology for liquid spills occurring on relatively impermeable surfaces such as concrete or asphalt pavement and the development and application of a model to describe the time evolution of such spills. The discussion assumes evaporation and degradation are negligible and a homogeneous surface. In such an instance, the inherent interfacial properties determine the spatial extent of liquid spreading with the initial flow being controlled by the release rate of the spill and by the liquids resistance to flow as characterized by its viscosity. A variety of spill scenarios were simulated and successful implementation of the model was achieved. A linear relationship between spill area and spill volume was confirmed. The simulations showed spill rate had little effect on the final spill area. Slope had an insignificant effect on the final spill area, but did modify spill shape considerably. However, a fluid sink on the edge of the simulation domain, representing a storm drain, resulted in a substantial decrease in spill area. A bona fide effort to determine the accuracy of the model and its calculations remain, but comparison against observations from a simple experiment showed the model to correctly determine the spill area and general shape under the conditions considered. Further model verification in the form of comparison against small scale spill experiments are needed to confirm the models validity.
Ferry Kwakkel
2011-12-01
Full Text Available Given a closed Riemannian manifold (M, g, i.e. compact and boundaryless, there is a partition of its tangent bundle TM = ∪iΣi called the focal decomposition of TM. The sets Σi are closely associated to focusing of geodesics of (M, g, i.e. to the situation where there are exactly i geodesic arcs of the same length joining points p and q in M. In this note, we study the topological structure of the focal decomposition of a closed Riemannian manifold and its relation with the metric structure of the manifold. Our main result is that flat n-tori, n > 2, are focally rigid in the sense that if two flat tori are focally equivalent then the tori are isometric up to rescaling. The case n = 2 was considered before by F. Kwakkel.Dada uma variedade Riemanniana (M, g fechada, isto é, compacta e sem bordo, existe uma partição de seu fibrado tangente TM = ∪iΣi chamada decomposição focal de TM. Os conjuntos Σi estão intimamente associados ao modo como focalizam as geodésicas de (M,g, isto é, à situação em que existem exatamente i arcos de geodésica de mesmo comprimento unindo pontos p e q em M. Nesta nota, estudamos a estrutura topológica da decomposição focal de uma variedade Riemanniana fechada e sua relação com a estrutura métrica de M. Nosso principal resultado é que n-toros planos, n > 2, são focalmente rigidos, isto é, se dois toros planos são focalmente equivalentes, então os dois toros são isométricos módulo mudança de escala. O caso n = 2 foi considerado anteriormente por F. Kwakkel.
Flat hat glass diffractive optical beam shaper
Reichel, Steffen; Petzold, Uwe; Biertuempfel, Ralf; Vogt, Helge
2009-02-01
Many laser applications need a homogeneous - so called flat hat - light distribution in the application area. However, many laser emit Gaussian shaped light. The technology of diffractive optical elements (DOE) can be used to shape the Gaussian beam into a flat hat beam at a compact length. SCHOTT presents a DOE design of a flat hat DOE beam shaper made out of optical glass. Here the material glass has the significant advantage of high laser durability, low scattering losses, high resistance to temperature, moisture, and chemicals compared to polymer DOEs. Simulations and measurements on different DOEs for different wavelength, laser beam width, and laser divergence are presented. Surprisingly the flat hat DOE beam shaper depends only weakly on wavelength and beam width but strongly on laser divergence. Based on the good agreement between simulation and measurement an improved flat hat DOE beam shaper is also presented.
Cosmology in Conformally Flat Spacetime
Endean, Geoffrey
1997-04-01
A possible solution to cosmological age and redshift-distance difficulties has recently been proposed by applying the appropriate conformally flat spacetime (CFS) coordinates to the standard solution of the field equations in a standard dust model closed universe. Here it is shown that CFS time correctly measures the true age of the universe, thus answering a major theoretical objection to the proposal. It is also shown that the CFS interpretation leads to a strong Copernican principle and is in all other respects wholly self-consistent. The deceleration parameter q0 is related to t0, the present age of the universe divided by L, the scale length of its curvature (an absolute constant). The values of q0 and L are approximately 5/6 and 9.2 × 109 yr, respectively. It is shown that the universe started everywhere simultaneously, with no recession velocity until the effects of its closed topology became significant. Conclusions to the contrary in standard theory (the big bang) stem from a different definition of recession velocity. The theoretical present cosmological mass density is quantified as 4.4 × 10-27 kg m-3 approximately, thus greatly reducing, in a closed universe, the observational requirement to find hidden mass. It is also shown that the prediction of standard theory, for a closed universe, of collapse toward a big crunch termination, will not in fact take place.
SBC Internal Lamp P-flat Monitoring
Avila, R. J.; Chiaberge, M.; Bohlin, R.
2016-03-01
We report on a Cycle 23 calibration program to monitor the status of the SBC P-flat. We find random pixel to pixel changes to be small, with only 2% of pixels having changed by more than 3. There are coherent changes that we measure to be above the poisson errors, in some regions as high as 4% peak to peak. We recommend that the ACS team obtain new observations in order to create a new P-flat. We also measured the degradation of the deuterium lamp used to create internal flats. The brightness of the lamp is currently 65% of its initial level, the degradation being dependent on lifetime usage.
Flatness Control Using Roll Coolant Based on Predicted Flatness Variation in Cold Rolling Mills
Dohmae, Yukihiro; Okamura, Yoshihide
Flatness control for cold rolling mills is one of the important technologies for improving of product quality and productivity. In particular, poor flatness leads to strip tearing in the extreme case and, moreover, it significantly reduces productivity. Therefore, various flatness control system has been developed. The main actuators for flatness control are classified into two types; one is mechanical equipment such as roll bender, the other is roll coolant, which controls thermal expansion of roll. Flatness variation such as center buckle or edge wave is mainly controlled by mechanical actuator which has high response characteristics. On another front, flatness variation of local zone can be controlled by roll coolant although one's response is lower than the response of mechanical actuator. For accomplishing good flatness accuracy in cold rolling mills, it is important to improve the performance of coolant control moreover. In this paper, a new coolant control method based on flatness variation model is described. In proposed method, the state of coolant spray on or off is selected to minimize the flatness deviation by using predicted flatness variation. The effectiveness of developed system has been demonstrated by application in actual plant.
Studies on solar flat plate collector evaporation systems for tannery effluent (soak liquor)
SRITHAR K.; MANIA.
2006-01-01
Heat and mass transfer analysis of an incompressible, laminar boundary layer over solar flat plate collector evaporation systems for tannery effluent (soak liquor) is investigated. The goveming equations are solved for various liquid to air velocity ratios. Profiles of velocity, temperature and concentration as well as their gradients are presented. The heat transfer and mass transfer coefficients thus obtained are used to evaluate mass of water evaporated for an inclined fibre-reinforced plastic (FRP)solar flat plate collector (FPC) with and without cover. Comparison of these results with the experimental performance shows encouraging trend of good agreement between them.
B^F Theory and Flat Spacetimes
Waelbroeck, Henri
2009-01-01
We propose a reduced constrained Hamiltonian formalism for the exactly soluble $B \\wedge F$ theory of flat connections and closed two-forms over manifolds with topology $\\Sigma^3 \\times (0,1)$. The reduced phase space variables are the holonomies of a flat connection for loops which form a basis of the first homotopy group $\\pi_1(\\Sigma^3)$, and elements of the second cohomology group of $\\Sigma^3$ with value in the Lie algebra $L(G)$. When $G=SO(3,1)$, and if the two-form can be expressed as $B= e\\wedge e$, for some vierbein field $e$, then the variables represent a flat spacetime. This is not always possible: We show that the solutions of the theory generally represent spacetimes with ``global torsion''. We describe the dynamical evolution of spacetimes with and without global torsion, and classify the flat spacetimes which admit a locally homogeneous foliation, following Thurston's classification of geometric structures.
On certain geodesic conjugacies of flat cylinders
C S ARAVINDA; H A GURURAJA
2017-06-01
We prove $C^0$-conjugacy rigidity of any flat cylinder among two different classes of metrics on the cylinder, namely among the class of rotationally symmetric metrics and among the class of metrics without conjugate points.
Fuzzy Neural Model for Flatness Pattern Recognition
JIA Chun-yu; SHAN Xiu-ying; LIU Hong-min; NIU Zhao-ping
2008-01-01
For the problems occurring in a least square method model,a fuzzy model,and a neural network model for flatness pattern recognition,a fuzzy neural network model for flatness pattern recognition with only three-input and three-output signals was proposed with Legendre orthodoxy polynomial as basic pattern,based on fuzzy logic expert experiential knowledge and genetic-BP hybrid optimization algorithm.The model not only had definite physical meanings in its inner nodes,but also had strong self-adaptability,anti-interference ability,high recognition precision,and high velocity,thereby meeting the demand of high-precision flatness control for cold strip mill and providing a convenient,practical,and novel method for flatness pattern recognition.
Improved ferrous shielding for flat cables
Drechsler, R. J.
1969-01-01
To improve shielding of flat multicore cables, a thin, seamless ferrous shield around all cores optimizes low frequency magnetic shielding. Such shielding is covered with an ultrathin seamless coat of highly conductive nonferrous material.
High performance flat plate solar collector
Lansing, F. L.; Reynolds, R.
1976-01-01
The potential use of porous construction is presented to achieve efficient heat removal from a power producing solid and is applied to solar air heaters. Analytical solutions are given for the temperature distribution within a gas-cooled porous flat plate having its surface exposed to the sun's energy. The extracted thermal energy is calculated for two different types of plate transparency. Results show the great improvement in performance obtained with porous flat plate collectors as compared with analogous nonporous types.
The effect of the density mismatch of liquids on scaling down steerable liquid lenses
Farcy, G.; Deladi, S.; Suijver, J.F.
2007-01-01
This report describes the results of the investigations on the effect of the gravity on downscaling the liquid lens. The configuration of the lens was chosen so that it enables steering of the interface between the two immiscible liquids in a flat position by electro wetting, which is important for
Topological properties of flat electroencephalography's state space
Ken, Tan Lit; Ahmad, Tahir bin; Mohd, Mohd Sham bin; Ngien, Su Kong; Suwa, Tohru; Meng, Ong Sie
2016-02-01
Neuroinverse problem are often associated with complex neuronal activity. It involves locating problematic cell which is highly challenging. While epileptic foci localization is possible with the aid of EEG signals, it relies greatly on the ability to extract hidden information or pattern within EEG signals. Flat EEG being an enhancement of EEG is a way of viewing electroencephalograph on the real plane. In the perspective of dynamical systems, Flat EEG is equivalent to epileptic seizure hence, making it a great platform to study epileptic seizure. Throughout the years, various mathematical tools have been applied on Flat EEG to extract hidden information that is hardly noticeable by traditional visual inspection. While these tools have given worthy results, the journey towards understanding seizure process completely is yet to be succeeded. Since the underlying structure of Flat EEG is dynamic and is deemed to contain wealthy information regarding brainstorm, it would certainly be appealing to explore in depth its structures. To better understand the complex seizure process, this paper studies the event of epileptic seizure via Flat EEG in a more general framework by means of topology, particularly, on the state space where the event of Flat EEG lies.
Flat H Frangible Joint Evolution
Diegelman, Thomas E.; Hinkel, Todd J.; Benjamin, Andrew; Rochon, Brian V.; Brown, Christopher W.
2016-01-01
Space vehicle staging and separation events require pyrotechnic devices. They are single-use mechanisms that cannot be tested, nor can failure-tolerant performance be demonstrated in actual flight articles prior to flight use. This necessitates the implementation of a robust design and test approach coupled with a fully redundant, failure-tolerant explosive mechanism to ensure that the system functions even in the event of a single failure. Historically, NASA has followed the single failure-tolerant (SFT) design philosophy for all human-rated spacecraft, including the Space Shuttle Program. Following the end of this program, aerospace companies proposed building the next generation human-rated vehicles with off-the-shelf, non-redundant, zero-failure-tolerant (ZFT) separation systems. Currently, spacecraft and launch vehicle providers for both the Orion and Commercial Crew Programs (CCPs) plan to deviate from the heritage safety approach and NASA's SFT human rating requirements. Both programs' partners have base-lined ZFT frangible joints for vehicle staging and fairing separation. These joints are commercially available from pyrotechnic vendors. Non-human-rated missions have flown them numerous times. The joints are relatively easy to integrate structurally within the spacecraft. In addition, the separation event is debris free, and the resultant pyro shock is lower than that of other design solutions. It is, however, a serious deficiency to lack failure tolerance. When used for critical applications on human-rated vehicles, a single failure could potentially lead to loss of crew (LOC) or loss of mission (LOM)). The Engineering and Safety & Mission Assurance directorates within the NASA Johnson Space Center took action to address this safety issue by initiating a project to develop a fully redundant, SFT frangible joint design, known as the Flat H. Critical to the ability to retrofit on launch vehicles being developed, the SFT mechanisms must fit within the same
Weathering of a liquid-filled solar collector
1979-01-01
Report describes procedures and results of tests for effects of weathering on flat-plate liquid solar collector. Thermal performance was measured before and after natural weathering for 15-1/2 months by using Marshall Space Flight solar simulator.
Sintered Nickel Powder Wicks for Flat Vertical Heat Pipes
Geir Hansen
2015-03-01
Full Text Available The fabrication and performance of wicks for flat heat pipe applications produced by sintering a filamentary nickel powder has been investigated. Tape casting was used as an intermediate step in the wick production process. Thermogravimetric analysis was used to study the burn-off of the organic binder used and to study the oxidation and reduction processes of the nickel. The wicks produced were flat, rectangular and intended for liquid transport in the upwards vertical direction. Rate-of-rise experiments using heptane were used to test the flow characteristics of the wicks. The wick porosities were measured using isopropanol. The heat transfer limitation constituted by the vapour static pressure and the capillary pressure was discussed. The influence on wick performance by using pore former in the manufacturing was studied. When Pcap/Psat > 1, the use of a pore former to increase the wick permeability will always improve the wick performance. When Pcap/Psat < 1, it was shown that if the effective pore radius and the permeability increase with an equal percentage the overall influence on the wick capacity is negative. A criterion for a successful pore former introduction is proposed and the concept of a pore former evaluation plot is presented.
Convection and segregation in a flat rotating sandbox
Rietz, Frank; Stannarius, Ralf
2012-01-01
A flat box, almost completely filled with a mixture of granulate, is rotated slowly about its horizontal central axis. In this experiment, a regular vortex flow of the granular material is observed in the cell plane. These vortex structures have a superficial analogy to convection rolls in dissipative structures of ordinary liquids. Whereas in the latter, the origin of the convection can often be attributed to gradients e.g. of densities or surface tensions, there is no trivial explanation at present for the convection of the granulate in the rotating container. Despite the simplicity of the experiment, the underlying mechanisms for convection and segregation are difficult to extract. Here, we present a comprehensive experimental study of the patterns under various experimental conditions and propose a mechanism for the convection.
Simulating confined particles with a flat density profile
Korolkovas, Airidas
2016-08-01
Particle simulations confined by sharp walls usually develop an oscillatory density profile. For some applications, most notably soft matter liquids, this behavior is often unrealistic and one expects a monotonic density climb instead. To reconcile simulations with experiments, we propose mirror-and-shift boundary conditions where each interface is mapped to a distant part of itself. The main result is that the particle density increases almost monotonically from zero to bulk, over a short distance of about one particle diameter. The method is applied to simulate a polymer brush in explicit solvent, grafted on a flat silicon substrate. The simulated density profile agrees favorably with neutron reflectometry measurements and self-consistent field theory results.
Droplet sorting in a loop of flat microfluidic channels
Kadivar, Erfan; Herminghaus, Stephan; Brinkmann, Martin
2013-07-01
Motivated by recent experiments, we numerically study the droplet traffic in microfluidic channels forming an asymmetric loop with a long and a short arm. The loop is connected to an inlet and an outlet channel by two right angled T-junctions. Assuming flat channels, we employ the boundary element method (BEM) to numerically solve the two-dimensional Darcy equation that governs two phase flow in the Hele-Shaw limit. The occurrence of different sorting regimes is summarized in sorting diagrams in terms of droplet size, distance between consecutive droplets in the inlet channel, and loop asymmetry for mobility ratios of the liquid phases larger and smaller than one. For large droplet distances, the traffic is regulated by the ratio of the total hydraulic resistances of the long and short arms. At high droplet densities and below a critical droplet size, droplet-droplet collisions are observed for both mobility ratios.
A Random Access Reconfigurable Metamaterial and a Tunable Flat Lens
Zhu, W M; Liu, A Q; Tsai, D P; Cai, H; Shen, Z X; Huang, R F; Ting, S K; Liang, Q X; Liu, H Z; Lu, B H; Zheludev, N I
2014-01-01
The ability to control resonant properties of individual metamolecule in a metamaterial structure will offer an ultimate freedom for dynamically shaping wavefronts of electromagnetic radiation for applications such as variable aberration corrected planar lenses, dynamic holograms and spatial intensity and phase modulators. Here we report the first demonstration of a metamaterial where resonant properties of every individual metamolecule can be continuously controlled at will thus offering an ultimate freedom in achieving a dynamic control of electromagnetic wavefront of microwave radiation. We call this a Random Access Reconfigurable Metamaterial (RARM). To achieve a RARM we created an array of cavities that were filled with liquid metal in a precise fashion using microfluidic technology. The developed RARM was used provide the first demonstration of a tunable flat lens.
Simulating confined particles with a flat density profile
Korolkovas, Airidas
2016-01-01
Particle simulations confined by sharp walls usually develop an oscillatory density profile. For some applications, most notably soft matter liquids, this behavior is often unrealistic and one expects a monotonic density climb instead. To reconcile simulations with experiments, we propose mirror-and-shift boundary conditions where each interface is mapped to a distant part of itself. The main result is that the particle density increases almost monotonically from zero to bulk, over a short distance of about one particle diameter. The method is applied to simulate a polymer brush in explicit solvent, grafted on a flat silicon substrate. The simulated density profile agrees favorably with neutron reflectometry measurements and self-consistent field theory results.
WFC3 UVIS Detector: Improved Flat Fields
Dahlen, Tomas; Mack, J.; Sabbi, E.; WFC3 Team
2012-01-01
We describe the improved flat field calibration for a set of UVIS broad-band filters that were delivered to MAST in August 2011. The total change peak-to-peak with respect to the previous pipeline flats ranges from 3.6% to 5.6%, increasing with wavelength. The flat-fields previously used in the pipeline were obtained during ground testing and contained a large reflection ghost (or flare) that affected 40% of the field. A simplified geometric model of the internal light reflections has been used to remove the flare from the ground flats. Residual low-frequency structures caused by differences in the ground-based and in-flight optical paths were then computed using photometry of Omega Centauri, observed at various roll angles and with large dithered steps. Furthermore, photometry in a range of apertures has been used to study the UVIS PSF in detail. For radii smaller than 0.4" (10 pixels) the PSF is strongly dependent on both the detector position and on the telescope focus at the time of observation. Therefore, the new pipeline flat fields have been normalized to "infinite" aperture by applying local aperture corrections to 10 pixels, making them more generally applicable.
Plasma Reforming of Liquid Hydrocarbon Fuels in Non-Thermal Plasma-Liquid Systems
2010-04-30
channel with liquid wall in the microporous media under the ultrasound cavitations has shown the following: · The action of the ultrasound field in the...microporous liquid which has a very large ratio of the plasma-liquid contact surface to the plasma volume. As is known the ultrasonic (US) cavitation is a very...2) and it ran over a flat dielectric surface of the magnetostrictive transmitter (5) which produced ultrasonic (US) cavitations , so the discharge
Heat transfer intensification by increasing vapor flow rate in flat heat pipes
Sprinceana, Silviu; Mihai, Ioan; Beniuga, Marius; Suciu, Cornel
2015-02-01
Flat heat pipes have various technical applications, one of the most important being the cooling of electronic components[9]. Their continuous development is due to the fact that these devices permit heat transfer without external energetic contribution. The practical exploitation of flat heat pipes however is limited by the fact that dissipated power can only reach a few hundred watts. The present paper aims to advance a new method for the intensification of convective heat transfer. A centrifugal mini impeller, driven by a turntable which incorporates four permanent magnets was designed. These magnets are put in motion by another rotor, which in its turn includes two permanent magnets and is driven by a mini electrical motor. Rotation of the centrifugal blades generates speed and pressure increase of the cooling agent brought to vapor state within the flat micro heat pipe. It's well known that the liquid suffers biphasic transformations during heat transfer inside the heat pipe. Over the hotspot (the heat source being the electronic component) generated at one end of the heat pipe, convective heat transfer occurs, leading to sudden vaporization of the liquid. Pressures generated by newly formed vapors push them towards the opposite end of the flat heat pipe, where a finned mini heat sink is usually placed. The mini-heat exchanger is air-cooled, thus creating a cold spot, where vapors condensate. The proposed method contributes to vapor flow intensification by increasing their transport speed and thus leading to more intense cooling of the heat pipe.
Magnetized and Flat Beam Experiment at FAST
Halavanau, A. [Fermilab; Hyun, J. [Sokendai, Tsukuba; Mihalcea, D. [NIU, DeKalb; Piot, P. [NICADD, DeKalb; Sen, T. [Fermilab; Thangaraj, C. [Fermilab
2017-05-22
A photocathode, immersed in solenoidal magnetic field, can produce canonical-angular-momentum (CAM) dominated or “magnetized” electron beams. Such beams have an application in electron cooling of hadron beams and can also be uncoupled to yield asymmetric-emittance (“flat”) beams. In the present paper we explore the possibilities of the flat beam generation at Fermilab’s Accelerator Science and Technology (FAST) facility. We present optimization of the beam flatness and four-dimensional transverse emittance and investigate the mapping and its limitations of the produced eigen-emittances to conventional emittances using a skew-quadrupole channel. Possible application of flat beams at the FAST facility are also discussed.
Witten spinors on maximal, conformally flat hypersurfaces
Frauendiener, Jörg; Szabados, László B
2011-01-01
The boundary conditions that exclude zeros of the solutions of the Witten equation (and hence guarantee the existence of a 3-frame satisfying the so-called special orthonormal frame gauge conditions) are investigated. We determine the general form of the conformally invariant boundary conditions for the Witten equation, and find the boundary conditions that characterize the constant and the conformally constant spinor fields among the solutions of the Witten equations on compact domains in extrinsically and intrinsically flat, and on maximal, intrinsically globally conformally flat spacelike hypersurfaces, respectively. We also provide a number of exact solutions of the Witten equation with various boundary conditions (both at infinity and on inner or outer boundaries) that single out nowhere vanishing spinor fields on the flat, non-extreme Reissner--Nordstr\\"om and Brill--Lindquist data sets. Our examples show that there is an interplay between the boundary conditions, the global topology of the hypersurface...
Effective theory and emergent SU(2 ) symmetry in the flat bands of attractive Hubbard models
Tovmasyan, Murad; Peotta, Sebastiano; Törmä, Päivi; Huber, Sebastian D.
2016-12-01
In a partially filled flat Bloch band electrons do not have a well defined Fermi surface and hence the low-energy theory is not a Fermi liquid. Nevertheless, under the influence of an attractive interaction, a superconductor well described by the Bardeen-Cooper-Schrieffer (BCS) wave function can arise. Here we study the low-energy effective Hamiltonian of a generic Hubbard model with a flat band. We obtain an effective Hamiltonian for the flat band physics by eliminating higher-lying bands via the perturbative Schrieffer-Wolff transformation. At first order in the interaction energy we recover the usual procedure of projecting the interaction term onto the flat band Wannier functions. We show that the BCS wave function is the exact ground state of the projected interaction Hamiltonian, if a simple uniform pairing condition on the single-particle states is satisfied, and that the compressibility is diverging as a consequence of an emergent SU(2 ) symmetry. This symmetry is broken by second-order interband transitions resulting in a finite compressibility, which we illustrate for a one-dimensional ladder with two perfectly flat bands. These results motivate a further approximation leading to an effective ferromagnetic Heisenberg model. The gauge-invariant result for the superfluid weight of a flat band can be obtained from the ferromagnetic Heisenberg model only if the maximally localized Wannier functions in the Marzari-Vanderbilt sense are used. Finally, we prove an important inequality D ≥W2 between the Drude weight D and the winding number W , which guarantees ballistic transport for topologically nontrivial flat bands in one dimension.
Taming Past LTL and Flat Counter Systems
Demri, Stéphane; sangnier, Arnaud
2012-01-01
Reachability and LTL model-checking problems for flat counter systems are known to be decidable but whereas the reachability problem can be shown in NP, the best known complexity upper bound for the latter problem is made of a tower of several exponentials. Herein, we show that the problem is only NP-complete even if LTL admits past-time operators and arithmetical constraints on counters. Actually, the NP upper bound is shown by adequately combining a new stuttering theorem for Past LTL and the property of small integer solutions for quantifier-free Presburger formulae. Other complexity results are proved, for instance for restricted classes of flat counter systems.
Scalar Curvature and Intrinsic Flat Convergence
Sormani, Christina
2016-01-01
Herein we present open problems and survey examples and theorems concerning sequences of Riemannian manifolds with uniform lower bounds on scalar curvature and their limit spaces. Examples of Gromov and of Ilmanen which naturally ought to have certain limit spaces do not converge with respect to smooth or Gromov-Hausdorff convergence. Thus we focus here on the notion of Intrinsic Flat convergence, developed jointly with Wenger. This notion has been applied successfully to study sequences that arise in General Relativity. Gromov has suggested it should be applied in other settings as well. We first review intrinsic flat convergence, its properties, and its compactness theorems, before presenting the applications and the open problems.
Static cylindrical symmetry and conformal flatness
Herrera, L; Marcilhacy, G; Santos, N O
2004-01-01
We present the whole set of equations with regularity and matching conditions required for the description of physically meaningful static cylindrically symmmetric distributions of matter, smoothly matched to Levi-Civita vacuum spacetime. It is shown that the conformally flat solution with equal principal stresses represents an incompressible fluid. It is also proved that any conformally flat cylindrically symmetric static source cannot be matched through Darmois conditions to the Levi-Civita spacetime. Further evidence is given that when the Newtonian mass per unit length reaches 1/2 the spacetime has plane symmetry.
The flat phase of quantum polymerized membranes
Coquand, O
2016-01-01
We investigate the flat phase of quantum polymerized phantom membranes by means of a nonperturbative renormalization group approach. We first implement this formalism for general quantum polymerized membranes and derive the flow equations that encompass both quantum and thermal fluctuations. We then deduce and analyze the flow equations relevant to study the flat phase and discuss their salient features : quantum to classical crossover and, in each of these regimes, strong to weak coupling crossover. We finally illustrate these features in the context of free standing graphene physics.
Ultimate resolution of indefinite metamaterial flat lenses
Bénédicto, Jessica; Pollès, Rémi; Moreau, Antoine
2013-01-01
We show that any metallo-dielectric multilayer with a hyperbolic dispersion relation can actually be characterized by a complex effective index. This refractive index, extracted from the complex Bloch band diagram, can be directly linked to the super-resolution of a flat lens made of this so- called indefinite metamaterials. This allows for a systematic optimization of the lens design, leading to structures that are outperforming state-of-art flat lenses. We show that, even when fully taking absorption into account, our design provides super-resolved images for visible light up to a distance of one wavelength from the lens edge.
Viability in the production of a drug extracted from Ananas comosus by a flat membrane system
Francisco Luiz Gumes Lopes
2012-06-01
Full Text Available The aim of this work was to study the production of e bromelain from the Ananas comosus L. Merril, by determining the process conditions using flat membranes. The production system modeling generated a hyperbolical curve and the optimization by response surfaces showed an influence of the transmembrane pressure higher than the pH influence. The cost of the production of bromelain from A. comosus was estimated 9 to 13 times lower than Sigma's retail sales price and 6.5 to 8.5 times lower than when this enzyme was obtained through a liquid-liquid extraction, which showed the economical feasibility of the process.
Film Condensation with and Without Body Force in Boundary-Layer Flow of Vapor Over a Flat Plate
Chung, Paul M.
1961-01-01
Laminar film condensation under the simultaneous influence of gas-liquid interface shear and body force (g force) is analyzed over a flat plate. Important parameters governing condensation and heat transfer of pure vapor are determined. Mixtures of condensable vapor and noncondensable gas are also analyzed. The conditions under which the body force has a significant influence on condensation are determined.
Noncommutative Topological Half-flat Gravity
García-Compéan, H; Ramírez, C
2004-01-01
We formulate a noncommutative description of topological half-flat gravity in four dimensions. BRST symmetry of this topological gravity is deformed through a twisting of the usual BRST quantization of noncommutative gauge theories. Finally it is argued that resulting moduli space of instantons is characterized by the solutions of a noncommutative version of the Plebanski's heavenly equation.
Affleck Dine leptogenesis via multiple flat directions
Kamada, Kohei
2008-01-01
We investigate the Affleck-Dine mechanism when multiple flat directions have large values simultaneously. We consider in detail the case when both $LH_u$ and $H_uH_d$ flat directions are operative with a non-renormalizable superpotential. In case Hubble induced A-terms are present for these two flat directions, their initial values are determined completely by the potential and there are no ambiguities how they are mixed. Moreover, CP is violated even when the Hubble parameter is large due to the Hubble induced A-term and cross coupling in F-term, so that the lepton asymmetry is generated just after the end of inflation. As a result, compared with the case of single flat direction, the resultant lepton-to-entropy ratio is enhanced by a factor of $H_{osc}/m_{3/2}$, where $H_{osc}$ is the Hubble parameter at the onset of oscillation and $m_{3/2}$ is the gravitino mass. However, when Hubble induced A-terms do not exist, there remains indefiniteness of initial phases and CP is violated spontaneously by the phase ...
η-Invariant and Flat Vector Bundles
无
2006-01-01
We present an alternate definition of the mod Z component of the AtiyahPatodi-Singer η invariant associated to (not necessary unitary) fiat vector bundles, which identifies explicitly its real and imaginary parts. This is done by combining a deformation of flat connections introduced in a previous paper with the analytic continuation procedure appearing in the original article of Atiyah, Parodi and Singer.
Chemically patterned flat stamps for microcontact printing
Sharpe, Ruben B.A.; Burdinski, Dirk; Huskens, Jurriaan; Zandvliet, Harold J.W.; Reinhoudt, David N.; Poelsema, Bene
2005-01-01
Locally oxidized patterns on flat poly(dimethylsiloxane) stamps for microcontact printing were used as a platform for the transfer of a hydrophilic fluorescent ink to a glass substrate. The contrast was found to be limited. These locally oxidized patterns were conversely used as barriers for the tra
Minimal Flat Resolutions of Artinian Modules
Sh. Payrovi
2005-01-01
The purpose of this paper is to establish connection between the minimal flat resolutions of Artinian modules and the concept of cosequences in commutative algebra.The main result of this paper leads to a characterization of local Cohen-Macaulay rings in terms of vanishing property of the dual Bass numbers of certain Artinian modules.
Wideband Flat Radomes Using Inhomogeneous Planar Layers
Mohammad Khalaj-Amirhosseini
2008-01-01
Full Text Available Inhomogeneous planar layers (IPLs are optimally designed as flat radomes in a desired frequency range. First, the electric permittivity function of the IPL is expanded in a truncated Fourier series. Then, the optimum values of the coefficients of the series are obtained through an optimization approach. The performance of the proposed structure is verified using some examples.
Design scenarios for flat panel photobioreactors
Slegers, P.M.; Wijffels, R.H.; Straten, van G.; Boxtel, van A.J.B.
2011-01-01
Evaluation of the potential of algae production for biofuel and other products at various locations throughout the world requires assessment of algae productivity under varying light conditions and different reactor layouts. A model was developed to predict algae biomass production in flat panel
Holography of 3d Flat Cosmological Horizons
Bagchi, Arjun; Fareghbal, Reza; Simon, Joan
2013-01-01
We provide a first derivation of the Bekenstein-Hawking entropy of 3d flat cosmological horizons in terms of the counting of states in a dual field theory. These horizons appear in the shifted-boost orbifold of R^{1,2}, the flat limit of non-extremal rotating BTZ black holes. These 3d geometries carry non-zero charges under the asymptotic symmetry algebra of R^{1,2}, the 3d Bondi-Metzner-Sachs (BMS3) algebra. The dual theory has the symmetries of the 2d Galilean Conformal Algebra, a contraction of two copies of the Virasoro algebra, which is isomorphic to BMS3. We study flat holography as a limit of AdS3/CFT2 to semi-classically compute the density of states in the dual, exactly reproducing the bulk entropy in the limit of large charges. Our flat horizons, remnants of the BTZ inner horizons also satisfy a first law of thermodynamics. We comment on how the dual theory reproduces the bulk first law and how cosmological bulk excitations are matched with boundary quantum numbers.
Gratings Fabricated on Flat Surfaces and Reproduced on Non-Flat Substrates
Content, David; Iazikov, Dmitri; Mossberg, Thomas W.; Greiner, Christopher M.
2009-01-01
A method has been developed for fabricating gratings on flat substrates, and then reproducing the groove pattern on a curved (concave or convex) substrate and a corresponding grating device. First, surface relief diffraction grating grooves are formed on flat substrates. For example, they may be fabricated using photolithography and reactive ion etching, maskless lithography, holography, or mechanical ruling. Then, an imprint of the grating is made on a deformable substrate, such as plastic, polymer, or other materials using thermoforming, hot or cold embossing, or other methods. Interim stamps using electroforming, or other methods, may be produced for the imprinting process or if the same polarity of the grating image is required. The imprinted, deformable substrate is then attached to a curved, rigid substrate using epoxy or other suitable adhesives. The imprinted surface is facing away from the curved rigid substrate. As an alternative fabrication method, after grating is imprinted on the deformable substrate as described above, the grating may be coated with thin conformal conductive layer (for example, using vacuum deposition of gold). Then the membrane may be mounted over an opening in a pressured vessel in a manner of a membrane on a drum, grating side out. The pressure inside of the vessel may be changed with respect to the ambient pressure to produce concave or convex membrane surface. The shape of the opening may control the type of the surface curvature (for example, a circular opening would create spherical surface, oval opening would create toroidal surface, etc.). After that, well-known electroforming methods may be used to create a replica of the grating on the concave or convex membrane. For example, the pressure vessel assembly may be submerged into an electro-forming solution and negative electric potential applied to the metal coated membrane using an insulated wire. Positive electric potential may be then applied to a nickel or other metal
Xu, Junli; Kjos, Ole Sigmund; Osen, Karen Sende; Martinez, Ana Maria; Kongstein, Ole Edvard; Haarberg, Geir Martin
2016-11-01
A new kind of membrane free liquid metal battery was developed. The battery employs liquid sodium and zinc as electrodes both in liquid state, and NaCl-CaCl2 molten salts as electrolyte. The discharge flat voltage is in the range of about 1.4 V-1.8 V, and the cycle efficiency achieved is about 90% at low discharge current densities (below 40 mA cm-2). Moreover, this battery can also be charged and discharged at high current density with good performance. The discharge flat voltage is above 1.1 V when it is discharged at 100 mA cm-2, while it is about 0.8 V with 100% cycle efficiency when it is discharged at 200 mA cm-2. Compared to other reported liquid metal battery, this battery has lower cost, which suggests broad application prospect in energy storage systems for power grid.
Gorenstein flatness and injectivity over Gorenstein rings
2008-01-01
Let R be a Gorenstein ring.We prove that if I is an ideal of R such that R/I is a semi-simple ring,then the Gorenstein flat dimension of R/I as a right R-module and the Gorenstein injective dimension of R/I as a left R-module are identical.In addition,we prove that if R→S is a homomorphism of rings and SE is an injective cogenerator for the category of left S-modules,then the Gorenstein flat dimension of S as a right R-module and the Gorenstein injective dimension of E as a left R-module are identical.We also give some applications of these results.
Perturbations of spiky strings in flat spacetimes
Bhattacharya, Soumya; Panigrahi, Kamal L
2016-01-01
Perturbations of a class of semiclassical strings known today as spiky strings, are studied using the well-known Jacobi equations for small normal deformations of an embedded timelike surface. It is shown that there exists finite normal perturbations of the spiky string worldsheets embedded in a $2+1$ dimensional flat spacetime. Such perturbations lead to a rounding off the spikes, which, in a way, demonstrates the stable nature of the unperturbed worldsheet. The same features appear for the dual spiky string solution and in the spiky as well as their dual solutions in $3+1$ dimensional flat spacetime. Our results are based on exact solutions of the corresponding Jacobi equations which we obtain and use while constructing the profiles of the perturbed configurations.
Improving the durability of flat roof constructions
Rudbeck, Claus Christian; Svendsen, Sv Aa Højgaard
1999-01-01
Flat roof constructions are mainly used on commercial, institutional and industrial buildings, where insulation is placed on top of the load-bearing deck and then covered with a roof membrane. Through time, there is a risk that the membrane will allow water passage as holes might form due...... as there is no easy method of drying it. To be able to dry the insulation, and thereby regain the functional requirements of the roofing system, two new solutions for insulating flat roofs with existing materials are proposed for high density mineral wool and expanded polystyrene. Monitoring equipment are part...... to weathering effects or physical loads. Water will then enter the insulation, and as a vapor retarder is normally found below the insulation thus trapping the water in the insulation, the leak can remain undetected for a long period. When the leak is finally discovered, the insulation has to be discharged...
Standard specification for silvered flat glass mirror
American Society for Testing and Materials. Philadelphia
2008-01-01
1.1 This specification covers the requirements for silvered flat glass mirrors of rectangular shape supplied as cut sizes, stock sheets or as lehr ends and to which no further processing (such as edgework or other fabrication) has been done. 1.2 This specification covers the quality requirements of silvered annealed monolithic clear and tinted flat glass mirrors up to 6 mm (¼ in.) thick. The mirrors are intended to be used indoors for mirror glazing, for components of decorative accessories or for similar uses. 1.3 This specification does not address safety glazing materials nor requirements for mirror applications. Consult model building codes and other applicable standards for safety glazing applications. 1.4 Mirrors covered in this specification are not intended for use in environments where high humidity or airborne corrosion promoters, or both, are consistently present (such as swimming pool areas, ocean-going vessels, chemical laboratories and other corrosive environments). 1.5 The dimensional val...
Towards a flat 45%-efficient concentrator module
Mohedano, Rubén, E-mail: rmohedano@lpi-europe.com; Hernandez, Maikel; Vilaplana, Juan; Chaves, Julio; Sorgato, S.; Falicoff, Waqidi [LPI, Altadena, CA, USA and Madrid (Spain); Miñano, Juan C.; Benitez, Pablo [LPI, Altadena, CA, USA and Madrid (Spain); Universidad Politécnica de Madrid (UPM), Campus de Montegancedo, Madrid (Spain)
2015-09-28
The so-called CCS{sup 4}FK is an ultra-flat photovoltaic system of high concentration and high efficiency, with potential to convert, ideally, the equivalent of a 45% of direct solar radiation into electricity by optimizing the usage of sun spectrum and by collecting part of the diffuse radiation, as a flat plate does. LPI has recently finished a design based on this concept and is now developing a prototype based on this technology, thanks to the support of FUNDACION REPSOL-Fondo de Emprendedores, which promotes entrepreneur projects in different areas linked to energy. This works shows some details of the actual design and preliminary potential performance expected, according to accurate spectral simulations.
A Flat World with Deep Fractures
Emil Constantinescu
2016-10-01
Full Text Available The Internet manages to connect different parts of the world, defies geographical distances and gives the impression that our planet is flat, but the Internet is there only for the ones who have the possibility and the ability to use it. Our contemporary flat world has deep transversal fractures which, like in many geological structures, make a direct connection between layers with different characteristics. The elites are moving across information avenues with targets set in the future; at the same time, in many parts of our planet, there are people organizing their lives in pre-modern agrarian cycles. Diversity in ways of living and in social organization is a sign of human freedom, not a sign of error, so, having different alternatives to achieving prosperity and happiness should be good news. Holding dear to a society’s lifestyle should not push for the destruction of societies with different sets of values.
Flat roof integration. CPT solar (AET IV)
Chianese, D.; Pola, I.; Bernasconi, A.; Bura, E.; Cereghetti, N.; Realini, A.; Pasinelli, P.; Rioggi, S.
2007-11-15
This illustrated final report for the Swiss Federal Office of Energy (SFOE) takes a look at a 15.4 kWp solar power installation in Trevano, Switzerland, that features flexible amorphous silicon triple-junction modules, mounted nearly horizontally and directly laminated to flexible polyolefin membranes that form the covering of a flat roof. The main objective of this study was to verify in which order of magnitude the better thermal behaviour of amorphous silicon cells can compensate for losses due to the quasi-horizontal roof integration (lower irradiation and higher reflection), and thus be competitive in the flat roof construction and refurbishment markets. The modules used and their characteristics are described. Performance, temperature levels and energy-production are reviewed for the panels of the installation. The performance of the inverter used is also reviewed. Data on temperatures and production are presented in graphical form and optical losses are examined.
Emergent universe in spatially flat cosmological model
Zhang, Kaituo; Yu, Hongwei
2013-01-01
The scenario of an emergent universe provides a promising resolution to the big bang singularity in universes with positive or negative spatial curvature. It however remains unclear whether the scenario can be successfully implemented in a spatially flat universe which seems to be favored by present cosmological observations. In this paper, we study the stability of Einstein static state solutions in a spatially flat Shtanov-Sahni braneworld scenario. With a negative dark radiation term included and assuming a scalar field as the only matter energy component, we find that the universe can stay at an Einstein static state past eternally and then evolve to an inflation phase naturally as the scalar field climbs up its potential slowly. In addition, we also propose a concrete potential of the scalar field that realizes this scenario.
Efficient defrosting of an inclined flat surface
Subrata Roy; Haribalan Kumar; Anderson, R. [Kettering University, Flint, MI (United States). Computational Plasma Dynamics Laboratory
2005-06-01
We present a deicing simulation for a practical three-dimensional geometry inside which hot air jets impinge upon a flat inclined glass surface with a layer of ice on the outside. The main goal is to study the unsteady two-phase melting process over the inclined flat surface, and to identify the traditional control parameters such as jet impingement angles for minimization of the defrosting time for given ice and glass thicknesses. A correlation for defrosting as functions of time, heat transfer parameters and impingement angles has been found. Also, in this study, the first Joule heating defroster using transparent electrodes are proposed and numerically simulated as a viable alternative. A correlation between the electrical Joule power requirement and the defrosting time is given. It is demonstrated that substantial improvements (roughly 70% reduction) in defrosting time may be achieved using Joule heating compared to the traditional jet impingement HVAC technology. (author)
Towards a flat 45%-efficient concentrator module
Mohedano, Rubén; Hernandez, Maikel; Vilaplana, Juan; Chaves, Julio; Miñano, Juan C.; Benitez, Pablo; Sorgato, S.; Falicoff, Waqidi
2015-09-01
The so-called CCS4FK is an ultra-flat photovoltaic system of high concentration and high efficiency, with potential to convert, ideally, the equivalent of a 45% of direct solar radiation into electricity by optimizing the usage of sun spectrum and by collecting part of the diffuse radiation, as a flat plate does. LPI has recently finished a design based on this concept and is now developing a prototype based on this technology, thanks to the support of FUNDACION REPSOL-Fondo de Emprendedores, which promotes entrepreneur projects in different areas linked to energy. This works shows some details of the actual design and preliminary potential performance expected, according to accurate spectral simulations.
Wash Flats Management Plan Chincoteague National Wildlife Refuge 1980
US Fish and Wildlife Service, Department of the Interior — The Wash Flats impoundments comprise an area of approximately 1,200 acres. Prior to 1963, the Wash Flats was subject to periodic wash-over during extremely high...
Shrinkage and trajectory of the flat jet with inclination angle
Shufeng Ye; Yusheng Xie; Hongzhi Guo; Ye Huang; Shantong Jin
2003-01-01
The performance of the flat jet with an inclination angle was investigated by a water model. A mathematical model for theshrinkage and the trajectory of the flat jet with an inclination angle was derived theoretically and verified by experimental data of thewater model. The experimental results indicate that the inclination angle (α) has no influence on the shrinkage of the flat jet, theshrinkage of the flat jet along the width direction decreases with the increasing of the initial velocity at the exit (u0) and the initialthickness of the flat jet (t0). Enough bigger initial exit velocity (u0) and initial thickness can suppress the shrinkage of the flat jetalong the width direction and keep the flat jet stabilized. In addition, the trajectory of the flat jet with an inclination angle is parabolicand must be taking into consideration when to determine the striking distance.
Superheater Tube Flat Wall Stationary Temperature Field
Parpiev A.T.
2016-01-01
Full Text Available The BKZ-220-100-9 steam generator platen superheater tube flat wall stationary temperature fields analysis have been made. The six steel grades, using in boiler fabrication, namely, St. 10, St. 20, 12H1MF, 15HM, 1H18N9T and 12H18N12T, have been used. The temperature curves calculation has been made by using outer and inner surface heat-transfer coefficients nine different combinations.
EXTRUDED POLYSTYRENE FOAM IN FLAT ROOFS
Zhukov Aleksey Dmitrievich
2014-09-01
Full Text Available In our article we prove the necessity of applying thermal insulation with low water absorption and resistance and preserving mechanical and thermophysical properties in corrosive environment in flat roofs, where there is always a danger of penetrating condensed moisture into the structure. As such material we offered extruded polystyrene foam - heat-insulating polymer material with uniformly distributed closed cells. The products are used in the form of slab insulation and special items - for forming slopes and venting.
Phosphors for flat panel emissive displays
Anderson, M.T.; Walko, R.J.; Phillips, M.L.F.
1995-07-01
An overview of emissive display technologies is presented. Display types briefly described include: cathode ray tubes (CRTs), field emission displays (FEDs), electroluminescent displays (ELDs), and plasma display panels (PDPs). The critical role of phosphors in further development of the latter three flat panel emissive display technologies is outlined. The need for stable, efficient red, green, and blue phosphors for RGB fall color displays is emphasized.
Superfluidity in topologically nontrivial flat bands.
Peotta, Sebastiano; Törmä, Päivi
2015-11-20
Topological invariants built from the periodic Bloch functions characterize new phases of matter, such as topological insulators and topological superconductors. The most important topological invariant is the Chern number that explains the quantized conductance of the quantum Hall effect. Here we provide a general result for the superfluid weight Ds of a multiband superconductor that is applicable to topologically nontrivial bands with nonzero Chern number C. We find that the integral over the Brillouin-zone of the quantum metric, an invariant calculated from the Bloch functions, gives the superfluid weight in a flat band, with the bound Ds⩾|C|. Thus, even a flat band can carry finite superfluid current, provided the Chern number is nonzero. As an example, we provide Ds for the time-reversal invariant attractive Harper-Hubbard model that can be experimentally tested in ultracold gases. In general, our results establish that a topologically nontrivial flat band is a promising concept for increasing the critical temperature of the superconducting transition.
Graphene nanoribbons production from flat carbon nanotubes
Melo, W. S.; Guerini, S.; Diniz, E. M., E-mail: eduardo.diniz@ufma.br [Departamento de Física, Universidade Federal do Maranhão, São Luís - MA 65080-805 (Brazil)
2015-11-14
Graphene nanoribbons are of great interest for pure and applied sciences due to their unique properties which depend on the nanoribbon edges, as, for example, energy gap and antiferromagnetic coupling. Nevertheless, the synthesis of nanoribbons with well-defined edges remains a challenge. To collaborate with this subject, here we propose a new route for the production of graphene nanoribbons from flat carbon nanotubes filled with a one-dimensional chain of Fe atoms by first principles calculations based on density functional theory. Our results show that Fe-filled flat carbon nanotubes are energetically more stable than non flattened geometries. Also we find that by hydrogenation or oxygenation of the most curved region of the Fe-filled flat armchair carbon nanotube, it occurred a spontaneous production of zigzag graphene nanoribbons which have metallic or semiconducting behavior depending on the edge and size of the graphene nanoribbon. Such findings can be used to create a new method of synthesis of regular-edge carbon nanoribbons.
Remote geologic structural analysis of Yucca Flat
Foley, M.G.; Heasler, P.G.; Hoover, K.A. (Pacific Northwest Lab., Richland, WA (United States)); Rynes, N.J. (Northern Illinois Univ., De Kalb, IL (United States)); Thiessen, R.L.; Alfaro, J.L. (Washington State Univ., Pullman, WA (United States))
1991-12-01
The Remote Geologic Analysis (RGA) system was developed by Pacific Northwest Laboratory (PNL) to identify crustal structures that may affect seismic wave propagation from nuclear tests. Using automated methods, the RGA system identifies all valleys in a digital elevation model (DEM), fits three-dimensional vectors to valley bottoms, and catalogs all potential fracture or fault planes defined by coplanar pairs of valley vectors. The system generates a cluster hierarchy of planar features having greater-than-random density that may represent areas of anomalous topography manifesting structural control of erosional drainage development. Because RGA uses computer methods to identify zones of hypothesized control of topography, ground truth using a well-characterized test site was critical in our evaluation of RGA's characterization of inaccessible test sites for seismic verification studies. Therefore, we applied RGA to a study area centered on Yucca Flat at the Nevada Test Site (NTS) and compared our results with both mapped geology and geologic structures and with seismic yield-magnitude models. This is the final report of PNL's RGA development project for peer review within the US Department of Energy Office of Arms Control (OAC) seismic-verification community. In this report, we discuss the Yucca Flat study area, the analytical basis of the RGA system and its application to Yucca Flat, the results of the analysis, and the relation of the analytical results to known topography, geology, and geologic structures. 41 refs., 39 figs., 2 tabs.
Remote geologic structural analysis of Yucca Flat
Foley, M.G.; Heasler, P.G.; Hoover, K.A. [Pacific Northwest Lab., Richland, WA (United States); Rynes, N.J. [Northern Illinois Univ., De Kalb, IL (United States); Thiessen, R.L.; Alfaro, J.L. [Washington State Univ., Pullman, WA (United States)
1991-12-01
The Remote Geologic Analysis (RGA) system was developed by Pacific Northwest Laboratory (PNL) to identify crustal structures that may affect seismic wave propagation from nuclear tests. Using automated methods, the RGA system identifies all valleys in a digital elevation model (DEM), fits three-dimensional vectors to valley bottoms, and catalogs all potential fracture or fault planes defined by coplanar pairs of valley vectors. The system generates a cluster hierarchy of planar features having greater-than-random density that may represent areas of anomalous topography manifesting structural control of erosional drainage development. Because RGA uses computer methods to identify zones of hypothesized control of topography, ground truth using a well-characterized test site was critical in our evaluation of RGA`s characterization of inaccessible test sites for seismic verification studies. Therefore, we applied RGA to a study area centered on Yucca Flat at the Nevada Test Site (NTS) and compared our results with both mapped geology and geologic structures and with seismic yield-magnitude models. This is the final report of PNL`s RGA development project for peer review within the US Department of Energy Office of Arms Control (OAC) seismic-verification community. In this report, we discuss the Yucca Flat study area, the analytical basis of the RGA system and its application to Yucca Flat, the results of the analysis, and the relation of the analytical results to known topography, geology, and geologic structures. 41 refs., 39 figs., 2 tabs.
[Present state and future of flat panel detector in Japan].
Higashida, Yoshiharu
2002-01-01
In our country, the introduction of flat panel detector is carried out in the diagnosis region since before several years. In flat panel detector with the high image characteristic, large expectation is being placed. In this paper, image characteristic of flat panel detector and effectiveness of clinical application were reviewed. It is anticipated that flat panel detector with the excellent image characteristic gives large effect in the radiological diagnosis.
L1TV Computes the Flat Norm for Boundaries
Simon P. Morgan
2007-01-01
Full Text Available We show that the recently introduced L1TV functional can be used to explicitly compute the flat norm for codimension one boundaries. Furthermore, using L1TV, we also obtain the flat norm decomposition. Conversely, using the flat norm as the precise generalization of L1TV functional, we obtain a method for denoising nonboundary or higher codimension sets. The flat norm decomposition of differences can made to depend on scale using the flat norm with scale which we define in direct analogy to the L1TV functional. We illustrate the results and implications with examples and figures.
Absolute flatness testing of skip-flat interferometry by matrix analysis in polar coordinates.
Han, Zhi-Gang; Yin, Lu; Chen, Lei; Zhu, Ri-Hong
2016-03-20
A new method utilizing matrix analysis in polar coordinates has been presented for absolute testing of skip-flat interferometry. The retrieval of the absolute profile mainly includes three steps: (1) transform the wavefront maps of the two cavity measurements into data in polar coordinates; (2) retrieve the profile of the reflective flat in polar coordinates by matrix analysis; and (3) transform the profile of the reflective flat back into data in Cartesian coordinates and retrieve the profile of the sample. Simulation of synthetic surface data has been provided, showing the capability of the approach to achieve an accuracy of the order of 0.01 nm RMS. The absolute profile can be retrieved by a set of closed mathematical formulas without polynomial fitting of wavefront maps or the iterative evaluation of an error function, making the new method more efficient for absolute testing.
Recovery of ammonia from poultry litter using flat gas permeable membranes.
Rothrock, M J; Szögi, A A; Vanotti, M B
2013-06-01
The use of flat gas-permeable membranes was investigated as components of a new process to capture and recover ammonia (NH3) in poultry houses. This process includes the passage of gaseous NH3 through a microporous hydrophobic membrane, capture with a circulating dilute acid on the other side of the membrane, and production of a concentrated ammonium (NH4) salt. Bench- and pilot-scale prototype systems using flat expanded polytetrafluoroethylene (ePTFE) membranes and a sulfuric acid solution consistently reduced headspace NH3 concentrations from 70% to 97% and recovered 88% to 100% of the NH3 volatilized from poultry litter. The potential benefits of this technology include cleaner air inside poultry houses, reduced ventilation costs, and a concentrated liquid ammonium salt that can be used as a plant nutrient solution. Published by Elsevier Ltd.
Jet screech reduction with perforated flat reflector
Khan, Md. Tawhidul Islam; Teramoto, Kenbu; Matsuo, Shigeru; Setoguchi, Toshiaki
2008-09-01
In the present experimental study, investigations have been carried out to evaluate the performance of the new control technique of jet screech with different perforated flat reflectors. Mainly two types of porous flat reflectors had been used in the experiment. One reflector (reflector-V) designed for placing the reflector surface vertical to the jet axis, when, another type of reflector (reflector-H) designed for placing the reflecting surface horizontal to the jet axis. In both cases the reflectors had been placed at the nozzle (base tube with uniform cross-sectional area) exit. The diameter of the reflector-V was 15D when the diameter of the reflector-H was 10D. The porous area of the reflector-V was 6D and 4.5D for reflector-H where D indicated the diameter of the nozzle exit. The placement of the reflector at the exit of the nozzle reduces the sound pressure at the nozzle exit. Thus the muted sound can not excite the unstable disturbance at the nozzle exit and the loop of the feedback mechanism disappeared, finally, the generation of jet screech be cancelled. The suction space located at the back side of the porous surface of the reflector-V improves the efficiency of the screech control technique. However, in the case of reflector-H, the receptivity process of feedback loop had been controlled by reducing the disturbances at the effective shock fronts as well as at the nozzle exit. The performance of the proposed method was verified with a flat reflector concept and good performance in jet screech suppression has been confirmed in the case of porous reflector.
Jet Screech Reduction with Perforated Flat Reflector
2008-01-01
In the present experimental study, investigations have been carried out to evaluate the performance of the new control technique of jet screech with different perforated flat reflectors. Mainly two types of porous flat reflectors had been used in the experiment. One reflector (reflector-V) designed for placing the reflector surface vertical to the jet axis, when, another type of reflector (reflector-H) designed for placing the reflecting surface horizontal to the jet axis. In both cases the reflectors had been placed at the nozzle (base tube with uniform cross-sectional area)exit. The diameter of the reflector-V was 15D when the diameter of the reflector-H was 10D. The porous area of the reflector-V was 6D and 4.5D for reflector-H where D indicated the diameter of the nozzle exit. The placement of the reflector at the exit of the nozzle reduces the sound pressure at the nozzle exit. Thus the muted sound can not excite the unstable disturbance at the nozzle exit and the loop of the feedback mechanism disappeared, finally,the generation of jet screech be cancelled. The suction space located at the back side of the porous surface of the reflector-V improves the efficiency of the screech control technique. However, in the case of reflector-H, the receptivity process of feedback loop had been controlled by reducing the disturbances at the effective shock fronts as well as at the nozzle exit. The performance of the proposed method was verified with a flat reflector concept and good performance in jet screech suppression has been confirmed in the case of porous reflector.
How flat is our Universe really?
Okouma, P.M., E-mail: okouma@saao.ac.za [Department of Maths and Applied Maths, University of Cape Town, Rondebosch 7701, Cape Town (South Africa); South African Astronomical Observatory, Observatory, Cape Town (South Africa); African Institute for Mathematical Sciences, 6-8 Melrose Road, Muizenberg, Cape Town (South Africa); Centre for High Performance Computing, 15 Lower Hope St., Rosebank, Cape Town (South Africa); Fantaye, Y. [Astrophysics Sector, International School for Advanced Studies, SISSA, 34136 Trieste (Italy); Institute of Theoretical Astrophysics, University of Oslo, P.O. Box 1029 Blindern, N-0315, Oslo (Norway); Bassett, B.A. [Department of Maths and Applied Maths, University of Cape Town, Rondebosch 7701, Cape Town (South Africa); South African Astronomical Observatory, Observatory, Cape Town (South Africa); African Institute for Mathematical Sciences, 6-8 Melrose Road, Muizenberg, Cape Town (South Africa); Centre for High Performance Computing, 15 Lower Hope St., Rosebank, Cape Town (South Africa)
2013-02-12
Distance measurement provides no constraints on curvature independent of assumptions about the dark energy, raising the question, how flat is our Universe if we make no such assumptions? Allowing for general evolution of the dark energy equation of state with 20 free parameters that are allowed to cross the phantom divide, w(z)=−1, we show that while it is indeed possible to match the first peak in the Cosmic Microwave Background with non-flat models and arbitrary Hubble constant, H{sub 0}, the full WMAP7 and supernova data alone imply −0.12<Ω{sub k}<0.01 (2σ). If we add an H{sub 0} prior, this tightens significantly to Ω{sub k}=0.002±0.009. These constitute the most conservative and model-independent constraints on curvature available today, and illustrate that the curvature-dynamics degeneracy is broken by current data, with a key role played by the Integrated Sachs Wolfe effect rather than the distance to the surface of last scattering. If one imposes a quintessence prior on the dark energy (−1⩽w(z)⩽1) then just the WMAP7 and supernova data alone force the Universe to near flatness: Ω{sub k}=0.013±0.012. Finally, allowing for curvature, we find that all datasets are consistent with a Harrison–Zel'dovich spectral index, n{sub s}=1, at 2σ, illustrating the interplay between early and late Universe constraints.
Liquid Crystalline Semiconductors Materials, properties and applications
Kelly, Stephen; O'Neill, Mary
2013-01-01
This is an exciting stage in the development of organic electronics. It is no longer an area of purely academic interest as increasingly real applications are being developed, some of which are beginning to come on-stream. Areas that have already been commercially developed or which are under intensive development include organic light emitting diodes (for flat panel displays and solid state lighting), organic photovoltaic cells, organic thin film transistors (for smart tags and flat panel displays) and sensors. Within the family of organic electronic materials, liquid crystals are relative newcomers. The first electronically conducting liquid crystals were reported in 1988 but already a substantial literature has developed. The advantage of liquid crystalline semiconductors is that they have the easy processability of amorphous and polymeric semiconductors but they usually have higher charge carrier mobilities. Their mobilities do not reach the levels seen in crystalline organics but they circumvent all of t...
New asymptotically flat phantom wormhole solutions
Lobo, Francisco S N; Riazi, Nematollah
2012-01-01
A possible cause of the late-time cosmic acceleration is an exotic fluid with an equation of state lying within the phantom regime, i.e., $w=p/\\rho 0. Thus, there is no need to surgically paste the interior wormhole geometry to an exterior vacuum spacetime. We also consider the "volume integral quantifier", which provides useful information regarding the total amount of energy condition violating matter, and show that, in principle, it is possible to construct asymptotically flat wormhole solutions with an arbitrary small amount of energy condition violating matter.
The ADM mass of asymptotically flat hypersurfaces
de Lima, Levi Lopes
2011-01-01
We provide integral formulae for the ADM mass of asymptotically flat hypersurfaces in Riemannian manifolds with a certain warped product structure in a neighborhood of infinity, thus extending Lam's recent results on Euclidean graphs to this broader context. As applications we exhibit, in any dimension, new classes of manifolds for which versions of the Positive Mass and Riemannian Penrose inequalities hold and discuss a notion of quasi-local mass in this setting. The proof explores a novel connection between the co-vector defining the ADM mass of a hypersurface as above and the Newton tensor associated to its shape operator, which takes place in the presence of an ambient Killing field.
Maintaining collections with a flat budget
Sara E Morris
2017-03-01
Full Text Available This paper focuses on the various processes, methods and tough decisions made by the University of Kansas Libraries to provide library materials while maintaining a flat collections budget for over eight years. During this period, those responsible for the Libraries’ collections have implemented quick stop- gap measures, picked all the ‘low-hanging fruit’, and eventually canceled a large journal package. This case study will help other librarians facing the reality of maintaining collections at a time when budgets, changing formats and publication practices are all obstacles to providing patrons with what they need.
Atomically flat ultrathin cobalt ferrite islands.
Martín-García, Laura; Quesada, Adrián; Munuera, Carmen; Fernández, Jose F; García-Hernández, Mar; Foerster, Michael; Aballe, Lucía; de la Figuera, Juan
2015-10-21
A route for fabricating structurally perfect cobalt ferrite magnetic nanostructures is demonstrated. Ultrathin islands of up to 100 μm(2) with atomically flat surfaces and free from antiphase boundaries are developed. The extremely low defect concentration leads to a robust magnetic order, even for thicknesses below 1 nm, and exceptionally large magnetic domains. This approach allows the evaluation of the influence of specific extrinsic effects on domain wall pinning. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Atomically flat single terminated oxide substrate surfaces
Biswas, Abhijit; Yang, Chan-Ho; Ramesh, Ramamoorthy; Jeong, Yoon H.
2017-05-01
Scientific interest in atomically controlled layer-by-layer fabrication of transition metal oxide thin films and heterostructures has increased intensely in recent decades for basic physics reasons as well as for technological applications. This trend has to do, in part, with the coming post-Moore era, and functional oxide electronics could be regarded as a viable alternative for the current semiconductor electronics. Furthermore, the interface of transition metal oxides is exposing many new emergent phenomena and is increasingly becoming a playground for testing new ideas in condensed matter physics. To achieve high quality epitaxial thin films and heterostructures of transition metal oxides with atomically controlled interfaces, one critical requirement is the use of atomically flat single terminated oxide substrates since the atomic arrangements and the reaction chemistry of the topmost surface layer of substrates determine the growth and consequent properties of the overlying films. Achieving the atomically flat and chemically single terminated surface state of commercially available substrates, however, requires judicious efforts because the surface of as-received substrates is of chemically mixed nature and also often polar. In this review, we summarize the surface treatment procedures to accomplish atomically flat surfaces with single terminating layer for various metal oxide substrates. We particularly focus on the substrates with lattice constant ranging from 4.00 Å to 3.70 Å, as the lattice constant of most perovskite materials falls into this range. For materials outside the range, one can utilize the substrates to induce compressive or tensile strain on the films and explore new states not available in bulk. The substrates covered in this review, which have been chosen with commercial availability and, most importantly, experimental practicality as a criterion, are KTaO3, REScO3 (RE = Rare-earth elements), SrTiO3, La0.18Sr0.82Al0.59Ta0.41O3 (LSAT), Nd
Geotechnical risk analysis by flat dilatometer (DMT)
Amoroso, Sara; Monaco, Paola
2015-04-01
In the last decades we have assisted at a massive migration from laboratory testing to in situ testing, to the point that, today, in situ testing is often the major part of a geotechnical investigation. The State of the Art indicates that direct-push in situ tests, such as the Cone Penetration Test (CPT) and the Flat Dilatometer Test (DMT), are fast and convenient in situ tests for routine site investigation. In most cases the DMT estimated parameters, in particular the undrained shear strength su and the constrained modulus M, are used with the common design methods of Geotechnical Engineering for evaluating bearing capacity, settlements etc. The paper focuses on the prediction of settlements of shallow foundations, that is probably the No. 1 application of the DMT, especially in sands, where undisturbed samples cannot be retrieved, and on the risk associated with their design. A compilation of documented case histories that compare DMT-predicted vs observed settlements, was collected by Monaco et al. (2006), indicating that, in general, the constrained modulus M can be considered a reasonable "operative modulus" (relevant to foundations in "working conditions") for settlement predictions based on the traditional linear elastic approach. Indeed, the use of a site investigation method, such as DMT, that improve the accuracy of design parameters, reduces risk, and the design can then center on the site's true soil variability without parasitic test variability. In this respect, Failmezger et al. (1999, 2015) suggested to introduce Beta probability distribution, that provides a realistic and useful description of variability for geotechnical design problems. The paper estimates Beta probability distribution in research sites where DMT tests and observed settlements are available. References Failmezger, R.A., Rom, D., Ziegler, S.R. (1999). "SPT? A better approach of characterizing residual soils using other in-situ tests", Behavioral Characterics of Residual Soils, B
Flexible Polyhedral Surfaces with Two Flat Poses
Hellmuth Stachel
2015-05-01
Full Text Available We present three types of polyhedral surfaces, which are continuously flexible and have not only an initial pose, where all faces are coplanar, but pass during their self-motion through another pose with coplanar faces (“flat pose”. These surfaces are examples of so-called rigid origami, since we only admit exact flexions, i.e., each face remains rigid during the motion; only the dihedral angles vary. We analyze the geometry behind Miura-ori and address Kokotsakis’ example of a flexible tessellation with the particular case of a cyclic quadrangle. Finally, we recall Bricard’s octahedra of Type 3 and their relation to strophoids.
High Performance Atomically Thin Flat Lenses
Lin, Han; Qiu, Chengwei; Jia, Baohua; Bao, Qiaoliang
2016-01-01
We experimentally demonstrate ultrathin flat lenses with a thickness of 7 {\\AA}, which corresponds to the fundamental physical limit of the thickness of the material, is fabricated in a large area, monolayer, CVD-prepared tungsten chalcogenides single crystals using the low-cost flexible laser writing method. The lenses apply the ultra-high refractive index to introduce abrupt amplitude modulation of the incident light to achieve three-dimensional (3D) focusing diffraction-limited resolution (0.5{\\lambda}) and a focusing efficiency as high as 31%. An analytical physical model based diffraction theory is derived to simulate the focusing process, which shows excellent agreement with the experimental results.
Plutonium in a grassland ecosystem. [Rocky Flats Plant
Little, C.A.
1976-08-01
A study was made of plutonium contamination of grassland at the Rocky Flats plant northwest of Denver, Colorado. Of interest were: the definition of major plutonium-containing ecosystem compartments; the relative amounts in those compartments; how those values related to studies done in other geographical areas; whether or not the predominant isotopes, /sup 238/Pu and /sup 239/Pu, behaved differently; and what mechanisms might have allowed for the observed patterns of contamination. Samples of soil, litter, vegetation, arthropods, and small mammals were collected for Pu analysis and mass determination from each of two macroplots. Small aliquots (5 g or less) were analyzed by a rapid liquid scintillation technique and by alpha spectrometry. Of the compartments sampled, greater than 99 percent of the total plutonium was contained in the soil and the concentrations were significantly inversely correlated with distance from the contamination source, depth of the sample, and particle size of the sieved soil samples. The soil data suggested that the distribution of contamination largely resulted from physical transport processes.
High temperature flat plate solar collector
Hozumi, S.; Aso, S.; Ebisu, K.; Uchino, H.
1981-04-01
Improvements in the efficiency of collectors are of great importance for extending the utilization of solar energy for heating and cooling in homes. A highly efficient collector makes the system size small and decreases the system cost effectively. From the view of the amount of energy collected, the efficient collector has a multiple effect, not only because of the high increase in instantaneous efficiency, but also because of the large usable intensity range of the insolation. On the basis of a functional analysis for a flat collector, the materials and parameters were selected and optimized, and a new high temperature flat collector was designed. The collector has 2 panes. The first pane is low iron glass and the second pane is a thin film of fluorinated ethylene-propylene copolymer. The overall solar transmittance for the two panes is 0.89. The collecting panel and its water paths were formed by means of welding and hydraulic expansion. The selective absorbing surface consists of colored stainless steel whose absorption characteristic is 0.89 and emission characteristic is 0.16. The thermal insulator preventing backward heatloss consists of double layers of urethane foam and glass wool. Furthermore, the sustained method for the second pane is contrived so as to prevent water condensation on the panes and excessive elevation of the absorber temperature during no load heating.
Cosmological consequences of supersymmetric flat directions
Riva, Francesco; Sarkar, Subir; Giudice, Gian
In this work we analyze various implications of the presence of large field vacum expectation values (VEVs) along supersymmetric flat direct ions during the early universe. First, we discuss supersymmetric leptogenesis and the grav itino bound. Supersym- metric thermal leptogenesis with a hierarchical right-han ded neutrino mass spectrum normally requires the mass of the lightest right-handed neu trino to be heavier than about 10 9 GeV. This is in conflict with the upper bound on the reheating t empera- ture which is found by imposing that the gravitinos generate d during the reheating stage after inflation do not jeopardize successful nucleosy nthesis. We show that a solution to this tension is actually already incorporated i n the framework, because of the presence of flat directions in the supersymmetric scalar potential. Massive right- handed neutrinos are efficiently produced non-thermally and the observed baryon asymmetry can be explained even for a reheating temperature respecting the grav- itino bound...
Asymptotically flat space-times: an enigma
Newman, Ezra T.
2016-07-01
We begin by emphasizing that we are dealing with standard Einstein or Einstein-Maxwell theory—absolutely no new physics has been inserted. The fresh item is that the well-known asymptotically flat solutions of the Einstein-Maxwell theory are transformed to a new coordinate system with surprising and (seemingly) inexplicable results. We begin with the standard description of (Null) asymptotically flat space-times described in conventional Bondi-coordinates. After transforming the variables (mainly the asymptotic Weyl tensor components) to a very special set of Newman-Unti (NU) coordinates, we find a series of relations totally mimicking standard Newtonian classical mechanics and Maxwell theory. The surprising and troubling aspect of these relations is that the associated motion and radiation does not take place in physical space-time. Instead these relations takes place in an unusual inherited complex four-dimensional manifold referred to as H-space that has no immediate relationship with space-time. In fact these relations appear in two such spaces, H-space and its dual space \\bar{H}.
Spectroscopic Detection of Chiral Aggregation at Liquid-Liquid Interfaces
无
2006-01-01
Two new spectroscopic methods to detect the optical activity of liquid-liquid interfaces have been developed. The first one is the centrifugal liquid membrane (CLM) method combined with a conventional circular dichroism (CD) spectropolarimetry and the second one is a more interfacial specific second harmonic generation CD (SHG-CD) spectrometry. In the CLM-CD method, a cylindrical glass cell containing small amounts of organic and aqueous phases was rotated at about 7000 r/min in a sample chamber of a CD spectropolarimeter to generate an interface with a high specific interfacial area between the two-phase liquid membranes. The CD spectra of the J-aggregate of protonated 5,10,15, 20-tetraphenylporphyrin formed at the toluene-sulfuric acid interface have been measured. As for the SHG-CD, a circularly polarized wavelength-variable fs-laser system was constructed to measure the interfacial SHG spectra of a flat liquid-liquid interface. The ion-associated aggregation of a water-soluble anionic porphyrin promoted with a cationic amphiphile at the heptane-water interface was observed by this technique and the observed SHG-CD spectra proved the generation of a characteristic optical activity accompanied by the formation of the interfacial aggregate of inherently achiral porphyrin molecules. These methods will pioneer a new field of interfacial chiral chemistry in the studies of solvent extraction mechanisms.
Market Liquidity and Funding Liquidity
Brunnermeier, Markus K; Lasse Heje Pedersen
2007-01-01
We provide a model that links an asset's market liquidity - i.e., the ease with which it is traded - and traders' funding liquidity - i.e., the ease with which they can obtain funding. Traders provide market liquidity, and their ability to do so depends on their availability of funding. Conversely, traders' funding, i.e., their capital and the margins they are charged, depend on the assets' market liquidity. We show that, under certain conditions, margins are destabilizing and market liquidit...
Market Liquidity and Funding Liquidity
Markus K. Brunnermeier; Lasse Heje Pedersen
2007-01-01
We provide a model that links an asset's market liquidity - i.e., the ease with which it is traded - and traders' funding liquidity - i.e., the ease with which they can obtain funding. Traders provide market liquidity, and their ability to do so depends on their availability of funding. Conversely, traders' funding, i.e., their capital and the margins they are charged, depend on the assets' market liquidity. We show that, under certain conditions, margins are destabilizing and market liquidit...
Flatness and Profile Integration Control Model for Tandem Cold Mills
2012-01-01
Using the effective matrix methods of flatness and profile control synthetically, the flatness and profile in- tegration control scheme for tandem cold mills is built in order to increase flatness and profile control precision of tan- dem cold mills. Corresponding control strategies are adopted for various control objectives of different stands and the coordination control strategies of various stands are given, which makes the on-line flatness control cooperate with on-line profile control and implements the parallel control of different stands. According to the measured flatness and profile data of some 1550 mm tandem cold mills, the control scheme is verified and the result indicates that the scheme has high flatness and profile control precision with steady and reliable control process. A new way and method is supplied for researching shade control of tandem cold mills.
Holography of 3D Asymptotically Flat Black Holes
Fareghbal, Reza
2014-01-01
We study the asymptotically flat rotating hairy black hole solution of a three-dimensional gravity theory which is given by taking flat-space limit (zero cosmological constant limit) of New Massive Gravity (NMG). We propose that the dual field theory of the flat-space limit of NMG can be described by a Contracted Conformal Field Theory (CCFT). Using Flat/CCFT correspondence we construct a stress tensor which yields the conserved charges of the asymptotically flat black hole solution. Furthermore, by taking appropriate limit of the Cardy formula in the parent CFT, we find a Cardy-like formula which reproduces the Wald's entropy of the 3D asymptotically flat black hole.
Holography of 3D asymptotically flat black holes
Fareghbal, Reza; Hosseini, Seyed Morteza
2015-04-01
We study the asymptotically flat rotating hairy black hole solution of a three-dimensional gravity theory which is given by taking the flat-space limit (zero cosmological constant limit) of new massive gravity. We propose that the dual field theory of the flat-space limit of new massive gravity can be described by a contracted conformal field theory which is invariant under the action of the BMS3 group. Using the flat/contracted conformal field theory correspondence, we construct a stress tensor which yields the conserved charges of the asymptotically flat black hole solution. We check that our expressions of the mass and angular momentum fit with the first law of black hole thermodynamics. Furthermore, by taking the appropriate limit of the Cardy formula in the parent conformal field theory, we find a Cardy-like formula which reproduces the Wald's entropy of the 3D asymptotically flat black hole.
TRANSVERSE MODES FOR FLAT INTER-BUNCH WAKES*
Burov, A
2013-01-01
If inter-bunch wake fields are flat, i.e. their variations over a bunch length can be neglected, all coherent modes have the same coupled-bunch structure, provided the bunches can be treated as identical by their inner qualities (train theorem). If a flat feedback is strong enough, the transverse modes are single-bunch, provided the inter-bunch wakes are also flat (damper theorem).
Prevalence of flat foot in preschool-aged children.
Pfeiffer, Martin; Kotz, Rainer; Ledl, Thomas; Hauser, Gertrude; Sluga, Maria
2006-08-01
Our aim with this study was to establish the prevalence of flat foot in a population of 3- to 6-year-old children to evaluate cofactors such as age, weight, and gender and to estimate the number of unnecessary treatments performed. A total of 835 children (411 girls and 424 boys) were included in this study. The clinical diagnosis of flat foot was based on a valgus position of the heel and a poor formation of the arch. Feet of the children were scanned (while they were in a standing position) by using a laser surface scanner, and rearfoot angle was measured. Rearfoot angle was defined as the angle of the upper Achilles tendon and the distal extension of the rearfoot. Prevalence of flexible flat foot in the group of 3- to 6-year-old children was 44%. Prevalence of pathological flat foot was flat foot decreases significantly with age: in the group of 3-year-old children 54% showed a flat foot, whereas in the group of 6-year-old children only 24% had a flat foot. Average rearfoot angle was 5.5 degrees of valgus. Boys had a significant greater tendency for flat foot than girls: the prevalence of flat foot in boys was 52% and 36% in girls. Thirteen percent of the children were overweight or obese. Significant differences in prevalence of flat foot between overweight, obese, and normal-weight children were observed. This study is the first to use a three-dimensional laser surface scanner to measure the rearfoot valgus in preschool-aged children. The data demonstrate that the prevalence of flat foot is influenced by 3 factors: age, gender, and weight. In overweight children and in boys, a highly significant prevalence of flat foot was observed; in addition, a retarded development of the medial arch in the boys was discovered. At the time of the study, > 90% of the treatments were unnecessary.
Development of Partial Tubular Flat Knitting Fabric Composite Preform
Jiang Wei Qing
2016-01-01
Full Text Available After building some structures of partial tubular flat knitting fabric composite preform, the influencing factor on tubular section was analyzed and the fabric was knitted selectively. The partial tubular flat knitting fabric composite preform were Knitted by changing different yarn, row number and two-sided partial tubular flat knitting fabric. Multilayer sheet would be got after hot pressing and it has big market prospects and good application value.
Improving the durability of flat roof constructions
Rudbeck, Claus Christian; Svendsen, Sv Aa Højgaard
1999-01-01
Flat roof constructions are mainly used on commercial, institutional and industrial buildings, where insulation is placed on top of the load-bearing deck and then covered with a roof membrane. Through time, there is a risk that the membrane will allow water passage as holes might form due...... to weathering effects or physical loads. Water will then enter the insulation, and as a vapor retarder is normally found below the insulation thus trapping the water in the insulation, the leak can remain undetected for a long period. When the leak is finally discovered, the insulation has to be discharged...... of the system, thereby making it easier to detect leaks faster. When a leak is detected, the membrane is repaired locally. In order to remove water which has already entered the insulation, an air gap or a system of air channels between the deck and the insulation is subjected to forced ventilation with outdoor...
Knitting Force Measurement on Flat Knitting Machines
A. Fouda
2014-01-01
Full Text Available Knittability can be defined as the ability of yarns to run on knitting machines without problems. Knittability can be achieved when less stress is applied on the knitting machine parts by the knitting yarns. This paper presents a novel measuring system for the knitting force needed to perform knitting yarns on flat knitting machine based on data acquisition system (DAS. The proposed system is used to measure the knitting force at different machine settings and different properties of the knitting yarns to determine the optimal production conditions. For this reason, three types of knitted fabric structures (single jersey, Rib 1 × 1, and full cardigan with three different loop lengths and five different twists of ply yarn were produced. The obtained results showed the optimal yarn ply twist factor (αe which gave minimum knitting force (less stress on needles or knitting yarns at different loop lengths for each structure.
Perfect Multi-Channel Flat Reflectors
Asadchy, V S; Elsakka, A; Albooyeh, M; Tretyakov, S A
2016-01-01
Recent advances in engineered gradient metasurfaces have enabled unprecedented opportunities for light manipulation using optically thin sheets, such as anomalous refraction, reflection, or focusing of an incident beam. Here we introduce a concept of multi-channel functional metasurfaces, which are able to control incoming and outgoing waves in a number of propagation directions or polarization states simultaneously and independently. In particular, we reveal a possibility to create perfect multi-channel reflectors. Under the assumption of reciprocity and energy conservation, we find that there exist three fundamental classes of multi-channel mirrors. Together they form a basis of all possible reflection functionalities achievable with flat periodically modulated reflectors. To demonstrate the potential of the introduced concept, we design and experimentally test one of the basis multi-channel reflectors, confirming the desired multi-channel response. Furthermore, by extending the concept to reflectors suppor...
Incompressible Polaritons in a Flat Band.
Biondi, Matteo; van Nieuwenburg, Evert P L; Blatter, Gianni; Huber, Sebastian D; Schmidt, Sebastian
2015-10-01
We study the interplay of geometric frustration and interactions in a nonequilibrium photonic lattice system exhibiting a polariton flat band as described by a variant of the Jaynes-Cummings-Hubbard model. We show how to engineer strong photonic correlations in such a driven, dissipative system by quenching the kinetic energy through frustration. This produces an incompressible state of photons characterized by short-ranged crystalline order with period doubling. The latter manifests itself in strong spatial correlations, i.e., on-site and nearest-neighbor antibunching combined with extended density-wave oscillations at larger distances. We propose a state-of-the-art circuit QED realization of our system, which is tunable in situ.
Topological flat bands from dipolar spin systems.
Yao, N Y; Laumann, C R; Gorshkov, A V; Bennett, S D; Demler, E; Zoller, P; Lukin, M D
2012-12-28
We propose and analyze a physical system that naturally admits two-dimensional topological nearly flat bands. Our approach utilizes an array of three-level dipoles (effective S=1 spins) driven by inhomogeneous electromagnetic fields. The dipolar interactions produce arbitrary uniform background gauge fields for an effective collection of conserved hard-core bosons, namely, the dressed spin flips. These gauge fields result in topological band structures, whose band gap can be larger than the corresponding bandwidth. Exact diagonalization of the full interacting Hamiltonian at half-filling reveals the existence of superfluid, crystalline, and supersolid phases. An experimental realization using either ultracold polar molecules or spins in the solid state is considered.
Rocky Flats experience with SDM/70
Sanders, J. W.
1979-01-01
SDM/70 is a comprehensive system for developing systems. It employs a series of phases designed for consistent, orderly progress through the entire system development life cycle, with heavy emphasis on interaction with the users in the early phases and straightforward, but thorough, documentation throughout. The overall package includes a standard structure of tasks and steps for each phase, methods guidelines, many good forms and tutorials on state-of-the-art techniques. It has guidelines for estimating costs and schedules, approaches for improving project management, and ways to match the effort to the size and type of project (even for small applications or maintenance and enhancement of existing systems). Reasons for adoption of a new methodology by the Computing and Information Systems Department at Rocky Flats are reviewed. The choice of SDM/70 is described, and the status after about a year's experience, including the benefits perceived during that time, is discussed. (RWR)
On asymptotic flatness and Lorentz charges
Compere, Geoffrey [KdV Institute for Mathematics, Universiteit van Amsterdam (Netherlands); Dehouck, Francois; Virmani, Amitabh, E-mail: gcompere@uva.nl, E-mail: fdehouck@ulb.ac.be, E-mail: avirmani@ulb.ac.be [Physique Theorique et Mathematique, Universite Libre de Bruxelles, Bruxelles (Belgium)
2011-07-21
In this paper we establish two results concerning four-dimensional asymptotically flat spacetimes at spatial infinity. First, we show that the six conserved Lorentz charges are encoded in two unique, distinct, but mutually dual symmetric divergence-free tensors that we construct from the equations of motion. Second, we show that the integrability of Einstein's equations in the asymptotic expansion is sufficient to establish the equivalence between counter-term charges defined from the variational principle and charges defined by Ashtekar and Hansen. These results clarify earlier constructions of conserved charges in the hyperboloid representation of spatial infinity. In showing this, the parity condition on the mass aspect is not needed. Along the way in establishing these results, we prove two lemmas on tensor fields on three-dimensional de Sitter spacetime stated by Ashtekar-Hansen and Beig-Schmidt and state and prove three additional lemmas.
Holographic Renormalization of Asymptotically Flat Gravity
Park, Miok
2012-01-01
We compute the boundary stress tensor associated with Mann-Marolf counterterm in asymptotic flat and static spacetime for cylindrical boundary surface as $r \\rightarrow \\infty$, and find that the form of the boundary stress tensor is the same as the hyperbolic boundary case in 4 dimensions, but has additional terms in higher than 4 dimensions. We find that these additional terms are impotent and do not contribute to conserved charges. We also check the conservation of the boundary stress tensor in a sense that $\\mathcal{D}^a T_{ab} = 0$, and apply our result to the ($n+3$)-dimensional static black hole solution. As a result, we show that the stress boundary tensor with Mann-Marolf counterterm works well in standard boundary surfaces.
Flat foot: a comparison of surgical methods.
Villani, C; Chiozzi, F; Persiani, P; Costantini, A
2003-01-01
The authors present a comparative review of cases concerning the results obtained in the treatment of idiopathic flat foot: the methods compared were Castaman exosinotarsal arthrorisis and Giannini endosinotarsal arthrorisis. Between 1990 and 1198 a total of 80 patients, of which 40 with calcaneo-stop, and 40 with Giannini screws, were submitted to surgery at the Orthopaedic and Traumatology Department of the University of Rome "La Sapienza". The clinical, radiographic and functional results were classified as good, fair and poor. The authors agree on the effectiveness of both methods based on the results obtained and the facility of implantation techniques, however emphasizing the minor injury of the anatomical structures of the subtalar joint when the calcaneo-stop method with Castaman conical screws was used.
FREE VIBRATION ANALYSIS OF FLAT THIN MEMBRANE
S.P. HARSHA
2012-08-01
Full Text Available This paper presents the vibration analysis for predicating the behavior of flat thin inflatable membrane structure. This is having rectangular shaped with a thickness in millimeter fabricated using the various smart materials. Within structural member, it is subjected to pre-stress rather than bending or moments. The deployable structure has the low weight (minimal mass to achieve high acceleration; large area & durable (easily withstand the temperature changes, micrometeoroid hazards in outer space. The objective of this paper is to optimize the smart material for the space satellite technology so that the light weight inflatable structure attracts in satellite application. The observations show the good agreement between finite element and analytical results.
Pulsar Magnetospheres: Beyond the Flat Spacetime Dipole
Gralla, Samuel E; Philippov, Alexander
2016-01-01
Most studies of the pulsar magnetosphere have assumed a pure magnetic dipole in flat spacetime. However, recent work suggests that the effects of general relativity are in fact of vital importance and that realistic pulsar magnetic fields may have a significant nondipolar component. We introduce a general analytical method for studying the axisymmetric force-free magnetosphere of a slowly-rotating star of arbitrary magnetic field, mass, radius and moment of inertia, including all the effects of general relativity. We confirm that spacelike current is generically present in the polar caps (suggesting a pair production region), irrespective of the stellar magnetic field. We show that general relativity introduces a ~60% correction to the formula for the dipolar component of the surface magnetic field inferred from spindown. Finally, we show that the location and size of the polar caps can be modified dramatically by even modestly strong higher moments. This can affect emission processes occurring near the star ...
Piecewise flat embeddings for hyperspectral image analysis
Hayes, Tyler L.; Meinhold, Renee T.; Hamilton, John F.; Cahill, Nathan D.
2017-05-01
Graph-based dimensionality reduction techniques such as Laplacian Eigenmaps (LE), Local Linear Embedding (LLE), Isometric Feature Mapping (ISOMAP), and Kernel Principal Components Analysis (KPCA) have been used in a variety of hyperspectral image analysis applications for generating smooth data embeddings. Recently, Piecewise Flat Embeddings (PFE) were introduced in the computer vision community as a technique for generating piecewise constant embeddings that make data clustering / image segmentation a straightforward process. In this paper, we show how PFE arises by modifying LE, yielding a constrained ℓ1-minimization problem that can be solved iteratively. Using publicly available data, we carry out experiments to illustrate the implications of applying PFE to pixel-based hyperspectral image clustering and classification.
Physiological Demands of Flat Horse Racing Jockeys.
Cullen, SarahJane; OʼLoughlin, Gillian; McGoldrick, Adrian; Smyth, Barry; May, Gregory; Warrington, Giles D
2015-11-01
The physiological demands of jockeys during competition remain largely unknown, thereby creating challenges when attempting to prescribe sport-specific nutrition and training guidelines. The purpose of this study was to evaluate the physiological demands and energy requirements of jockeys during flat racing. Oxygen uptake (V[Combining Dot Above]O2) and heart rate (HR) were assessed in 18 male trainee jockeys during a race simulation trial on a mechanical horse racing simulator for the typical time duration to cover a common flat race distance of 1,400 m. In addition, 8 male apprentice jockeys participated in a competitive race, over distances ranging from 1,200 to 1,600 m, during which HR and respiratory rate (RR) were assessed. All participants performed a maximal incremental cycle ergometer test. During the simulated race, peak V[Combining Dot Above]O2 was 42.74 ± 5.6 ml·kg·min (75 ± 11% of V[Combining Dot Above]O2peak) and below the mean ventilatory threshold (81 ± 5% of V[Combining Dot Above]O2peak) reported in the maximal incremental cycle test. Peak HR was 161 ± 16 b·min (86 ± 7% of HRpeak). Energy expenditure was estimated as 92.5 ± 18.8 kJ with an associated value of 9.4 metabolic equivalents. During the competitive race trial, peak HR reached 189 ± 5 b·min (103 ± 4% of HRpeak) and peak RR was 50 ± 7 breaths per minute. Results suggest that horse racing is a physically demanding sport, requiring jockeys to perform close to their physiological limit to be successful. These findings may provide a useful insight when developing sport-specific nutrition and training strategies to optimally equip and prepare jockeys physically for the physiological demands of horse racing.
A. Malvandi; Faraz Hedayati; Ganji, D.D.
2015-01-01
The falling and settling of solid particles in gases and liquids is a natural phenomenon happens in many industrial processes. This phenomenon has altered pure forced convection to a combination of heat conduction and heat convection in a flow over a plate. In this paper, the coupling of conduction (inside the plate) and forced convection of a non-homogeneous nanofluid flow (over a flat plate) is investigated, which is classified in conjugate heat transfer problems. Two-component four-equatio...
Injector for liquid fueled rocket engine
Cornelius, Charles S. (Inventor); Myers, W. Neill (Inventor); Shadoan, Michael David (Inventor); Sparks, David L. (Inventor)
2000-01-01
An injector for liquid fueled rocket engines wherein a generally flat core having a frustoconical dome attached to one side of the core to serve as a manifold for a first liquid, with the core having a generally circular configuration having an axis. The other side of the core has a plurality of concentric annular first slots and a plurality of annular concentric second slots alternating with the first slots, the second slots having a greater depth than said first slots. A bore extends through the core for inletting a second liquid into said core, the bore intersecting the second slots to feed the second liquid into the second slots. The core also has a plurality of first passageways leading from the manifold to the first annular slots for feeding the first liquid into said first slots. A faceplate brazed to said other side of the core is provided with apertures extending from the first and second slots through said face plate, these apertures being positioned to direct fuel and liquid oxygen into contact with each other in the combustion chamber. The first liquid may be liquid oxygen and the second liquid may be kerosene or liquid hydrogen.
Qutaiba A. Tawfic
2011-01-01
Full Text Available Mammals have lungs to breathe air and they have no gills to breath liquids. When the surface tension at the air-liquid interface of the lung increases, as in acute lung injury, scientists started to think about filling the lung with fluid instead of air to reduce the surface tension and facilitate ventilation. Liquid ventilation (LV is a technique of mechanical ventilation in which the lungs are insufflated with an oxygenated perfluorochemical liquid rather than an oxygen-containing gas mixture. The use of perfluorochemicals, rather than nitrogen, as the inert carrier of oxygen and carbon dioxide offers a number of theoretical advantages for the treatment of acute lung injury. In addition, there are non-respiratory applications with expanding potential including pulmonary drug delivery and radiographic imaging. The potential for multiple clinical applications for liquid-assisted ventilation will be clarified and optimized in future. Keywords: Liquid ventilation; perfluorochemicals; perfluorocarbon; respiratory distress; surfactant.
Tillage and nutrient source effects on water quality and corn grain yield from a flat landscape.
Thoma, David P; Gupta, Satish C; Strock, Jeffrey S; Moncrief, John F
2005-01-01
Beneficial effects of leaving residue at the soil surface are well documented for steep lands, but not for flat lands that are drained with surface inlets and tile lines. This study quantified the effects of tillage and nutrient source on tile line and surface inlet water quality under continuous corn (Zea mays L.) from relatively flat lands (<3%). Tillage treatments were either fall chisel or moldboard plow. Nutrient sources were either fall injected liquid hog manure or spring incorporated urea. The experiment was on a Webster-Canisteo clay loam (Typic Endoaquolls) at Lamberton, MN. Surface inlet runoff was analyzed for flow, total solids, NO(3)-N, NH(4)-N, dissolved P, and total P. Tile line effluent was analyzed for flow, NO(3)-N, and NH(4)-N. In four years of rainstorm and snowmelt events there were few significant differences (p < 0.10) in water quality of surface inlet or tile drainage between treatments. Residue cover minimally reduced soil erosion during both snowmelt and rainfall runoff events. There was a slight reduction in mineral N losses via surface inlets from manure treatments. There was also a slight decrease (p = 0.025) in corn grain yield from chisel-plow plots (9.7 Mg ha(-1)) compared with moldboard-plow plots (10.1 Mg ha(-1)). Chisel plowing (approximately 30% residue cover) alone is not sufficient to reduce nonpoint source sediment pollution from these poorly drained flat lands to the extent (40% reduction) desired by regulatory agencies.
Polymer Crystallization at Curved Liquid/Liquid Interface
Wang, Wenda
Liquid/liquid interface, either flat or curved, is a unique template for studying self-assembly of a variety of nanomaterials such as nanoparticles and nanorods. The resultant monolayer films can be ordered or disordered depending on the regularity of the nanomaterials. Integration of nanoparticles into two-dimensional structure leads to intriguing collective properties of the nanoparticles. Crystallization can also be guided by liquid/liquid interface. Due to the particular shape of the interface, crystallization can happen in a different manner comparing to the normal solution crystallization. In this dissertation, liquid/liquid interface is employed to guide the crystallization of polymers, mainly focusing on using curved liquid/liquid interface. Due to the unique shape of the interface and feasibility to control the curvature, polymer crystallization can take place in different manner and lead to the formation of curved or vesicular crystals. Curved liquid/liquid interface is typically created through o/w emulsions. With the presence of surfactant, the emulsions are controlled to be stable at least for the polymer crystallization periods. The difference to normal solution crystallization is: the nuclei will diffuse to the curved interface due to the Pickering effect and guide the crystallization along the curved liquid/liquid interface. If the supercooling can be controlled to be very small, crystal growth in the bulk droplets can be avoided. The advantages of this strategy are: 1) the formation process of vesicular type crystals can be monitored by controlling the polymer supply; 2) curved crystals, bowl-like structures and enclosed capsules can be easily obtained comparing to the self-assembly method for vesicle formation; 3) the obtained vesicles will be made of polymer crystals, which will possess the extraordinary mechanical properties. Based on the nucleation type, this dissertation is divided into two parts. The first part is focused on the self
The World Is Not Flat: Can People Reorient Using Slope?
Nardi, Daniele; Newcombe, Nora S.; Shipley, Thomas F.
2011-01-01
Studies of spatial representation generally focus on flat environments and visual input. However, the world is not flat, and slopes are part of most natural environments. In a series of 4 experiments, we examined whether humans can use a slope as a source of allocentric, directional information for reorientation. A target was hidden in a corner of…
Evaluation of photomask flatness compensation for extreme ultraviolet lithography
Ballman, Katherine; Lee, Christopher; Zimmerman, John; Dunn, Thomas; Bean, Alexander
2016-10-01
As the semiconductor industry continues to strive towards high volume manufacturing for EUV, flatness specifications for photomasks have decreased to below 10nm for 2018 production, however the current champion masks being produced report P-V flatness values of roughly 50nm. Write compensation presents the promising opportunity to mitigate pattern placement errors through the use of geometrically adjusted target patterns which counteract the reticle's flatness induced distortions and address the differences in chucking mechanisms between e-beam write and electrostatic clamping during scan. Compensation relies on high accuracy flatness data which provides the critical topographical components of the reticle to the write tool. Any errors included in the flatness data file are translated to the pattern during the write process, which has now driven flatness measurement tools to target a 6σ reproducibility write compensation is validated against printed wafer results. Topographic features which lack compensation capability must then be held to stringent specifications in order to limit their contributions to the final image placement error (IPE) at wafer. By understanding the capabilities and limitations of write compensation, it is then possible to shift flatness requirements towards the "non-correctable" portion of the reticle's profile, potentially relieving polishers from having to adhere to the current single digit flatness specifications.
Flat Files - JSNP | LSDB Archive [Life Science Database Archive metadata
Full Text Available switchLanguage; BLAST Search Image Search Home About Archive Update History Data ... Data file File name: jsnp_flat_files File URL: ftp://ftp.biosciencedbc.jp/archiv...his Database Database Description Download License Update History of This Database Site Policy | Contact Us Flat Files - JSNP | LSDB Archive ...
The Discourses of OERs: How "Flat" Is This World?
dos Santos, Andreia Inamorato
2008-01-01
This paper proposes Critical Discourse Analysis (Fairclough, 2000) as a tool for identifying the various discourses that can be found in the provision of open educational resources. The argument will be built upon the concept of a "flat world", a powerful metaphor used by Friedman in his famous book "The World is Flat" (2005). The discussion will…
The Flat Tax: Implications for Financing Public Schools.
Rossmiller, Richard A.
The campaign for the 1996 Republican presidential election focused attention on proposals to replace the current federal income tax system with a flat tax. This booklet examines the ramifications of a flat tax for local school funding. Section 1 outlines the criteria for evaluating proposed taxes and the purposes of tax systems. The second section…
On the Picard group of a compact flat projective variety
Michelacakis, NJ
1996-01-01
In this note, we describe the Picard group of the class of compact, smooth, flat, projective varieties. In view of Charlap's work and Johnson's characterization, we construct line bundles over such manifolds as the holonomy-invariant elements of the Neron-Severi group of a projective flat torus cove
Free energy of topologically massive gravity and flat space holography
Grumiller, Daniel
2015-01-01
We calculate the free energy from the on-shell action for topologically massive gravity with negative and vanishing cosmological constant, thereby providing a first principles derivation of the free energy of BTZ black holes and flat space cosmologies. We summarize related recent checks of flat space holography.
New face-centered photonic square lattices with flat bands
Zhang, Yiqi; Li, Changbiao; Zhang, Zhaoyang; Zhang, Yanpeng; Xiao, Min
2016-01-01
We report two new classes of face-centered photonic square lattices with flat bands which we call the Lieb-I and the Lieb-II lattices. There are 5 and 7 sites in the corresponding unit cells of the simplest Lieb-I and Lieb-II lattices, respectively. The number of flat bands $m$ in the new Lieb lattices is related to the number of sites $N$ in the unit cell by $m=(N-1)/2$. Physical properties of the lattices with even and odd number of flat bands are different. We also consider localization of light in such Lieb lattices. If the input beam excites the flat-band mode, it will not diffract during propagation, owing to the strong localization in the flat-band mode. For the Lieb-II lattice, we also find that the beam will oscillate and still not diffract during propagation, because of the intrinsic oscillating properties of certain flat-band modes. The period of oscillation is determined by the energy difference between the two flat bands. This study provides a new platform for the investigation of flat-band modes...
Tom Friedman on Education in the "Flat World"
School Administrator, 2008
2008-01-01
In his best-selling book, "The World Is Flat," Thomas Friedman describes that the real world is becoming "flat." He describes how 10 forces are "flattening" the 21st century--making it easier for people in India, China and around the world to compete with Americans and others who had triumphed the century before. This article presents an interview…
Flat-panel electronic displays: a triumph of physics, chemistry and engineering.
Hilsum, Cyril
2010-03-13
This paper describes the history and science behind the development of modern flat-panel displays, and assesses future trends. Electronic displays are an important feature of modern life. For many years the cathode ray tube, an engineering marvel, was universal, but its shape was cumbersome and its operating voltage too high. The need for a flat-panel display, working at a low voltage, became imperative, and much research has been applied to this need. Any versatile flat-panel display will exploit an electro-optical effect, a transparent conductor and an addressing system to deliver data locally. The first need is to convert an electrical signal into a visible change. Two methods are available, the first giving emission of light, the second modulating ambient illumination. The most useful light-emitting media are semiconductors, historically exploiting III-V or II-VI compounds, but more recently organic or polymer semiconductors. Another possible effect uses gas plasma discharges. The modulating, or subtractive, effects that have been studied include liquid crystals, electrophoresis, electrowetting and electrochromism. A transparent conductor makes it possible to apply a voltage to an extended area while observing the results. The design is a compromise, since the free electrons that carry current also absorb light. The first materials used were metals, but some semiconductors, when heavily doped, give a better balance, with high transmission for a low resistance. Delivering data unambiguously to a million or so picture elements across the display area is no easy task. The preferred solution is an amorphous silicon thin-film transistor deposited at each cross-point in an X-Y matrix. Success in these endeavours has led to many applications for flat-panel displays, including television, flexible displays, electronic paper, electronic books and advertising signs.
Malinova, Katya; Park, Andreas
2015-01-01
Facing increased competition over the last decade, many stock exchanges changed their trading fees to maker-taker pricing, an incentive scheme that rewards liquidity suppliers and charges liquidity demanders. Using a change in trading fees on the Toronto Stock Exchange, we study whether and why...
Shock wave interactions with liquid sheets
Jeon, H.; Eliasson, V.
2017-04-01
Shock wave interactions with a liquid sheet are investigated by impacting planar liquid sheets of varying thicknesses with a planar shock wave. A square frame was designed to hold a rectangular liquid sheet, with a thickness of 5 or 10 mm, using plastic membranes and cotton wires to maintain the planar shape and minimize bulge. The flat liquid sheet, consisting of either water or a cornstarch and water mixture, was suspended in the test section of a shock tube. Incident shock waves with Mach numbers of M_s = 1.34 and 1.46 were considered. A schlieren technique with a high-speed camera was used to visualize the shock wave interaction with the liquid sheets. High-frequency pressure sensors were used to measure wave speed, overpressure, and impulse both upstream and downstream of the liquid sheet. Results showed that no transmitted shock wave could be observed through the liquid sheets, but compression waves induced by the shock-accelerated liquid coalesced into a shock wave farther downstream. A thicker liquid sheet resulted in a lower peak overpressure and impulse, and a cornstarch suspension sheet showed a higher attenuation factor compared to a water sheet.
Controlling Liquid Release by Compressing Electrospun Nanowebs
K.G. Kornev
2009-09-01
Full Text Available Electrospun nanowebs with pores ranging from nanometers to micrometers, constitute new materials with enhanced absorbency and ability to retain liquids in pores for a long period of time. These materials can be used as nanofluidic probes collecting minute amount of liquids. However, extraction of liquids from nanofibrous materials presents a problem: menisci in the interfiber pores create very high suction pressure which holds the liquid inside the material. This problem can be resolved if the probe is completely filled with the liquid: menisci at the probe edges become flat to establish a pressure equilibrium with the atmosphere. Therefore, one can take advantage of the nanoweb softness and extract liquid by mechanically deforming the nanowebs. We show that the liquid-saturated nanowebs follow the Voigt-type rheology upon loading. We theoretically explain this behavior and derive the relations between the Voigt phenomenological parameters, nanoweb permeability and compression modulus. We show that the limiting deformations follow the Hooke’s law which assumes linear relation between the extracted volume of liquid and the applied load. Because of this predictable behavior, the nanoweb probes can be engineered to release minute liquid doses upon compression. The developed experimental methodology can be used for characterization of nanostructured materials which otherwise impossible to analyze by using the existing instruments.
Sagebrush Flat Wildlife Area 2008 Annual Report.
Peterson, Dan [Washington Department of Fish and Wildlife
2008-11-03
The Sagebrush Flat Wildlife Area is a 12,718 acre complex located in Douglas County, Washington. Four distinct management units make up the area: Bridgeport, Chester Butte, Dormaier and Sagebrush Flat. The four Units are located across a wide geographic area within Douglas County. The Units are situated roughly along a north/south line from Bridgeport in the north to the Douglas/Grant county line in the south, 60 miles away. The wildlife area was established to conserve and enhance shrubsteppe habitat for the benefit shrubsteppe obligate and dependent wildlife species. In particular, the Sagebrush Flat Wildlife Area is managed to promote the recovery of three state-listed species: Columbian sharp-tailed grouse (threatened), greater sage grouse (threatened) and the pygmy rabbit (endangered). The US Fish and Wildlife Service also list the pygmy rabbit as endangered. Wildlife area staff seeded 250 acres of old agricultural fields located on the Sagebrush Flat, Dormaier and Chester Butte units. This has been a three project to reestablish high quality shrubsteppe habitat on fields that had either been abandoned (Dormaier) or were dominated by non-native grasses. A mix of 17 native grasses and forbs, most of which were locally collected and grown, was used. First year maintenance included spot spraying Dalmatian toadflax on all sites and mowing annual weeds to reduce competition. Photo points were established and will be integral to long term monitoring and evaluation. Additional monitoring and evaluation will come from existing vegetation transects. This year weed control efforts included spot treatment of noxious weeds, particularly Dalmatian toadflax, in previously restored fields on the Bridgeport Unit (150 acres). Spot treatment also took place within fields scheduled for restoration (40 acres) and in areas where toadflax infestations are small and relatively easily contained. Where toadflax is so widespread that chemical treatment would be impractical, we use the
Beam uniformity of flat top lasers
Chang, Chao; Cramer, Larry; Danielson, Don; Norby, James
2015-03-01
Many beams that output from standard commercial lasers are multi-mode, with each mode having a different shape and width. They show an overall non-homogeneous energy distribution across the spot size. There may be satellite structures, halos and other deviations from beam uniformity. However, many scientific, industrial and medical applications require flat top spatial energy distribution, high uniformity in the plateau region, and complete absence of hot spots. Reliable standard methods for the evaluation of beam quality are of great importance. Standard methods are required for correct characterization of the laser for its intended application and for tight quality control in laser manufacturing. The International Organization for Standardization (ISO) has published standard procedures and definitions for this purpose. These procedures have not been widely adopted by commercial laser manufacturers. This is due to the fact that they are unreliable because an unrepresentative single-pixel value can seriously distort the result. We hereby propose a metric of beam uniformity, a way of beam profile visualization, procedures to automatically detect hot spots and beam structures, and application examples in our high energy laser production.
Pulsar Magnetospheres: Beyond the Flat Spacetime Dipole
Gralla, Samuel E.; Lupsasca, Alexandru; Philippov, Alexander
2016-12-01
Most studies of the pulsar magnetosphere have assumed a pure magnetic dipole in flat spacetime. However, recent work suggests that the effects of general relativity are in fact of vital importance and that realistic pulsar magnetic fields will have a significant nondipolar component. We introduce a general analytical method for studying the axisymmetric force-free magnetosphere of a slowly rotating star of arbitrary magnetic field, mass, radius, and moment of inertia, including all the effects of general relativity. We confirm that spacelike current is generically present in the polar caps (suggesting a pair production region), irrespective of the stellar magnetic field. We show that general relativity introduces a ∼ 60 % correction to the formula for the dipolar component of the surface magnetic field inferred from spindown. Finally, we show that the location and shape of the polar caps can be modified dramatically by even modestly strong higher moments. This can affect emission processes occurring near the star and may help explain the modified beam characteristics of millisecond pulsars.
Design of flat pneumatic artificial muscles
Wirekoh, Jackson; Park, Yong-Lae
2017-03-01
Pneumatic artificial muscles (PAMs) have gained wide use in the field of robotics due to their ability to generate linear forces and motions with a simple mechanism, while remaining lightweight and compact. However, PAMs are limited by their traditional cylindrical form factors, which must increase radially to improve contraction force generation. Additionally, this form factor results in overly complicated fabrication processes when embedded fibers and sensor elements are required to provide efficient actuation and control of the PAMs while minimizing the bulkiness of the overall robotic system. In order to overcome these limitations, a flat two-dimensional PAM capable of being fabricated using a simple layered manufacturing process was created. Furthermore, a theoretical model was developed using Von Karman’s formulation for large deformations and the energy methods. Experimental characterizations of two different types of PAMs, a single-cell unit and a multi-cell unit, were performed to measure the maximum contraction lengths and forces at input pressures ranging from 0 to 150 kPa. Experimental data were then used to verify the fidelity of the theoretical model.
Prunus hybrids rootstocks for flat peach
Pilar Legua
2012-02-01
Full Text Available Peach (Prunus persica L. is the most important stone fruit tree grown in Spain and is the second most important fruit crop in Europe. The influence of eight Prunus rootstocks (GF-677, Krymsk® 86, PADAC 97-36, PADAC 99-05, PADAC 9912-03, PADAC 0024-01, PAC 0021-01 and PAC 0022-01 on vigor, yield and fruit quality traits of 'UFO 3' flat peach cultivar was studied. The highest trunk cross sectional area was exhibited by GF-677 and the lowest by PADAC 99-05, while intermediate values were found on the other rootstocks. The highest yield efficiency was found on PADAC 99-05, PAC 0021-01, PAC 0022-01 and PADAC 0024-01 and the lowest was shown on Krymsk® 86. The fruit quality parameters measured were color, fruit and stone weights, equatorial diameter, pulp thickness, pulp yield, firmness, pH, soluble solids content and titratable acidity. 'UFO 3' grafted on GF-677 resulted in the largest fruit weight, while the smallest was on PADAC 99-05. Fruits of 'UFO 3' showed a tendency to have higher firmness, higher red colored skin and RI when grafted on PADAC 99-05.
Chemically patterned flat stamps for microcontact printing.
Sharpe, Ruben B A; Burdinski, Dirk; Huskens, Jurriaan; Zandvliet, Harold J W; Reinhoudt, David N; Poelsema, Bene
2005-07-27
Locally oxidized patterns on flat poly(dimethylsiloxane) stamps for microcontact printing were used as a platform for the transfer of a hydrophilic fluorescent ink to a glass substrate. The contrast was found to be limited. These locally oxidized patterns were conversely used as barriers for the transfer of hydrophobic n-octadecanethiol. In this case a good contrast was obtained, but the pattern was found to be susceptible to defects (cracks) in the barrier layer. Local stamp surface oxidation and subsequent modification with 1H,1H,2H,2H-perfluorodecyltrichlorosilane, for use as a barrier in the transfer of n-octadecanethiol, 16-mercaptohexadecanoic acid, and octanethiol, resulted in remarkably good contrast and stable patterns. The improved ink transfer control is ascribed to the reduction of undesired surface spreading and a superior mechanical stability of the stamp pattern. This new approach substantially expands the applicability of microcontact printing and provides a tool for the faithful reproduction of even extremely low filling ratio patterns.
Flat belt continuously variable high speed drive
Kumm, E.L.
1992-02-01
A study was undertaken at Kumm Industries funded by DOE in the NBS/DOE Energy-Related Inventions Program starting in August 1990 to design, construct and test a novel very high speed flat belt drive. The test arrangement as shown in Figure 1 consists of a multiple belt-pulley configuration that transmits power from a low speed (2000--4000 RPM) input to a small pulley turbine'' (27,000 to 55,000 RPM) and then to the low speed output variable radius pulley (2000--5000 RPM) via a special self-active tensioner. Transmitting 25 HP to and from the turbine'' corresponds to obtaining 50 HP in one direction only in a possible turbo compounded engine application. The high speed of the turbine'' belts, i.e. 100 meters/sec. at 55,000 RPM, while transferring substantial power is a new much higher operating regime for belts. The study showed that the available belts gave overall test rig efficiencies somewhat above 80% for the higher speeds (50,000 RPM) and higher powers (corresponding to above 90% in the turbocompound application) and a significantly better efficiencies at slightly lower speeds. The tests revealed a number of improved approaches in the design of such high speed drives. It appears that there is considerable possibility for further improvement and application of such equipment.
Military market for flat panel displays
Desjardins, Daniel D.; Hopper, Darrel G.
1997-07-01
This paper addresses the number, function and size of primary military displays and establishes a basis to determine the opportunities for technology insertion in the immediate future and into the next millennium. The military displays market is specified by such parameters as active area and footprint size, and other characteristics such as luminance, gray scale, resolution, color capability and night vision imaging system capability. A select grouping of funded, future acquisitions, planned and predicted cockpit kits, and form-fit-function upgrades are taken into account. It is the intent of this paper to provide an overview of the DoD niche market, allowing both government and industry a timely reference to insure meeting DoD requirements for flat-panel displays on schedule and in a cost-effective manner. The aggregate DoD market for direct view displays is presently estimated to be in excess of 157,000. Helmet/head mounted displays will add substantially to this total. The vanishing vendor syndrome for older display technologies is becoming a growing, pervasive problem throughout DoD, which consequently just leverage the more modern display technologies being developed for civil-commercial markets.
Bremond, Nicolas; Bibette, Jérôme
2010-01-01
This fluid dynamics video reports how to form liquid core capsules having a thin hydrogel elastic membrane named liquid pearls. These fish-egg like structures are initially made of a millimetric liquid drop, aqueous or not, coated with an aqueous liquid film containing sodium alginate that gels once the double drop enters a calcium chloride bath. The creation of such pearls with micrometer thick membrane requires to suppress mixing until gelling takes place. Here, we show that superimposing a two dimensional surfactant precipitation at the interface confers a transient rigidity that can damp the shear induced instability at impact. Based on this, pearls containing almost any type of liquids can be created. The video focuses on the dynamics of the entry of the compound drop into the gelling bath.
Barrow, John D; Barrow, John D.; Magueijo, Joao
1999-01-01
We define the flatness and quasi-flatness problems in cosmological models. We seek solutions to both problems in homogeneous and isotropic Brans-Dicke cosmologies with varying speed of light. We formulate this theory and find perturbative, non-perturbative, and asymptotic solutions using both numerical and analytical methods. For a particular range of variations of the speed of light the flatness problem can be solved. Under other conditions there exists a late-time attractor with a constant value of Ømega that is smaller than, but of order, unity. Thus these theories may solve the quasi-flatness problem, a considerably more challenging problem than the flatness problem. We also discuss the related \\Lambda and quasi-\\Lambda problem in these theories. We conclude with an appraisal of the difficulties these theories may face.
Evaluation of Interaction Between Flat Car and Container at Dynamic Coupling of Flat Cars
Nikitchenko Andrew
2016-01-01
Full Text Available Innovative materials and structures are analyzed in this paper. To calculate the strength of the collision of flat wagons for the transport of large containers, there is no clear methodology for determining effort interaction between the container and the platform. At high longitudinal acceleration of the container, it is set in motion, and the consideration of this problem in a static setting impossible. The relevance of this work is to develop a methodology that is based on the equations of motion and considers dynamic interaction between container and platform.
The Modelling of Flat Fluidised Photoreactors.
Iatridis, D.
Available from UMI in association with The British Library. The present research constitutes a systematic study towards the modelling and design of flat plate fluidised photoreactors. Light transmitted through a fluidised photoreactor (transmittance) and light reflected from the reactor (reflectance) have been measured by new optical techniques. These two important design variables were correlated with relevant fluidisation parameters. The average light transmittance was found to increase with bed expansion, the square root of particle diameter and inversely with bed thickness. On the other hand, the average light reflectance was found to decrease with bed height and particle diameter. The correlations found for light transmittance and reflectance with the fluidised parameters were tested with experimental data using two types of particles of different optical characteristics. The form of these correlations was not affected by the type of particles used. The light energy retained within a fluidised photoreactor, "light absorption", was evaluated by an energy balance from the measured values of light transmittance and reflectance. The light absorption data obtained were regressed for two different types of particles. For 13X zeolites the average light absorption by the bed was found to increase with the second power of bed height and the square root of particle diameter and reactor thickness. For Co-Mo-Al_2O _3 the average light absorption by the bed was found to increase with particle diameter and inversely with bed height. A theoretical study was made using the light energy retained within the reactor to promote a photochemical reaction of first order with respect to reactant concentration and to light absorption. The fluidised bed was treated as a single phase continuously stirred tank reactor (CSTR). The conversion of the reactant was found to increase with the light absorption and decrease with flow rate. This modelling approach may be extended to more complex
Flat norm decomposition of integral currents
Sharif Ibrahim
2016-05-01
Full Text Available Currents represent generalized surfaces studied in geometric measure theory. They range from relatively tame integral currents representing oriented compact manifolds with boundary and integer multiplicities, to arbitrary elements of the dual space of differential forms. The flat norm provides a natural distance in the space of currents, and works by decomposing a $d$-dimensional current into $d$- and (the boundary of $(d+1$-dimensional pieces in an optimal way.Given an integral current, can we expect its at norm decomposition to be integral as well? This is not known in general, except in the case of $d$-currents that are boundaries of $(d+1$-currents in $\\mathbb{R}^{d+1}$ (following results from a corresponding problem on the $L^1$ total variation ($L^1$TV of functionals. On the other hand, for a discretized at norm on a finite simplicial complex, the analogous statement holds even when the inputs are not boundaries. This simplicial version relies on the total unimodularity of the boundary matrix of the simplicial complex; a result distinct from the $L^1$TV approach.We develop an analysis framework that extends the result in the simplicial setting to one for $d$-currents in $\\mathbb{R}^{d+1}$, provided a suitable triangulation result holds. In $\\mathbb{R}^2$, we use a triangulation result of Shewchuk (bounding both the size and location of small angles, and apply the framework to show that the discrete result implies the continuous result for $1$-currents in $\\mathbb{R}^2$ .
Photonic crystal based polarization insensitive flat lens
Turduev, M.; Bor, E.; Kurt, H.
2017-07-01
The paper proposes a new design of an inhomogeneous artificially created photonic crystal lens structure consisting of annular dielectric rods to efficiently focus both transverse electric and transverse magnetic polarizations of light into the same focal point. The locations of each individual cell that contains the annular dielectric rods are determined according to a nonlinear distribution function. The inner and outer radii of the annular photonic dielectric rods are optimized with respect to the polarization insensitive frequency response of the transmission spectrum of the lens structure. The physical background of the polarization insensitive focusing mechanism is investigated in both spatial and frequency domains. Moreover, polarization independent wavefront transformation/focusing has been explored in detail by investigating the dispersion relation of the structure. Corresponding phase index distribution of the lens is attained for polarization insensitive normalized frequency range of a/λ = 0.280 and a/λ = 0.300, where a denotes the lattice constant of the designed structure and λ denotes the wavelength of the incident light. We show the wave transformation performance and focal point movement dynamics for both polarizations of the lens structure by specially adjusting the length of the structure. The 3D finite-difference time domain numerical analysis is also performed to verifiy that the proposed design is able to focus the wave regardless of polarization into approximately the same focal point (difference between focal distances of both polarizations stays below 0.25λ) with an operating bandwidth of 4.30% between 1476 nm and 1541 nm at telecom wavelengths. The main superiorities of the proposed lens structure are being all dielectric and compact, and having flat front and back surfaces, rendering the proposed lens design more practical in the photonic integration process in various applications such as optical switch
Pokutta, Sebastian; Schmaltz, Christian
2011-01-01
Large banking groups face the question of how to optimally allocate and generate liquidity: in a central liquidity hub or in many decentralized branches. We translate this question into a facility location problem under uncertainty. We show that volatility is the key driver behind (de...... above which it is advantageous to open a liquidity center and show that it is a function of the volatility and the characteristic of the bank network. Finally, we discuss the n-branch model for real-world banking groups (10-60 branches) and show that it can be solved with high granularity (100 scenarios...
Novel method for high accuracy figure measurement of optical flat
E, Kewei; Li, Dahai; Yang, Lijie; Guo, Guangrao; Li, Mengyang; Wang, Xuemin; Zhang, Tao; Xiong, Zhao
2017-01-01
Phase Measuring Deflectometry (PMD) is a non-contact, high dynamic-range and full-field metrology which becomes a serious competitor to interferometry. However, the accuracy of deflectometry metrology is strongly influenced by the level of the calibrations, including test geometry, imaging pin-hole camera and digital display. In this paper, we propose a novel method that can measure optical flat surface figure to a high accuracy. We first calibrate the camera using a checker pattern shown on a LCD display at six different orientations, and the last orientation is aligned at the same position as the test optical flat. By using this method, lens distortions and the mapping relationship between the CCD pixels and the subaperture coordinates on the test optical flat can be determined at the same time. To further reduce the influence of the calibration errors on measurements, a reference optical flat with a high quality surface is measured, and then the system errors in our PMD setup can be eliminated by subtracting the figure of the reference flat from the figure of the test flat. Although any expensive coordinates measuring machine, such as laser tracker and coordinates measuring machine are not applied in our measurement, our experimental results of optical flat figure from low to high order aberrations still show a good agreement with that from the Fizeau interferometer.
Classification of Flat Lagrangian Surfaces in Complex Lorentzian Plane
Bang-Yen CHEN; Johan FASTENAKELS
2007-01-01
One of the most fundamental problems in the study of Lagrangian submanifolds fromRiemannian geometric point of view is to classify Lagrangian immersions of real space forms intocomplex space forms. The main purpose of this paper is thus to classify flat Lagrangian surfaces inthe Lorentzian complex plane C12. Our main result states that there are thirty-eight families of flatLagrangian surfaces in C12. Conversely, every flat Lagrangian surface in C12 is locally congruent to oneof the thirty-eight families.
Flat structures on the deformations of Gepner chiral rings
Belavin, Alexander [L.D. Landau Institute for Theoretical Physics,Akademika Semenova av., 1-A, Chernogolovka, 142432 Moscow region (Russian Federation); Department of Quantum Physics, Institute for Information Transmission Problems,Bolshoy Karetny per. 19, 127994 Moscow (Russian Federation); Belavin, Vladimir [I.E. Tamm Department of Theoretical Physics, P.N. Lebedev Physical Institute,Leninsky av., 53, 119991 Moscow (Russian Federation); Department of Quantum Physics, Institute for Information Transmission Problems,Bolshoy Karetny per. 19, 127994 Moscow (Russian Federation)
2016-10-24
We propose a simple method for the computation of the flat coordinates and Saito primitive forms on Frobenius manifolds of the deformations of Jacobi rings associated with isolated singularities. The method is based on using a conjecture about integral representations for the flat coordinates and on the Saito cohomology theory. This reduces the computation to a simple linear problem. We consider the case of the deformed Gepner chiral rings. The knowledge of the flat structures of Frobenius manifolds can be used for exact solution of the models of the topological conformal field theories corresponding to these chiral rings.
A New Triangular Flat Shell Element With Drilling Rotations
Damkilde, Lars
2008-01-01
A new flat triangular shell element has been developed based on a newly developed triangular plate bending element by the author and a new triangular membrane element with drilling degrees of freedom. The advantage of the drilling degree of freedom is that no special precautions have to be made...... in connecting with assembly of elements. Due to the drilling rotations all nodal degrees of freedom have stiffness, and therefore no artificial suppression of degrees of freedom are needed for flat or almost flat parts of the shell structure....
A novel simple and accurate flatness measurement method
Thang, H L
2011-01-01
Flatness measurement of a surface plate is an intensive and old research topic. However ISO definition related and other measurement methods seem uneasy in measuring and/ or complicated in data analysis. Especially in reality, the mentioned methods don't take a clear and straightforward care on the inclining angle which is always included in any given flatness measurement. In this report a novel simple and accurate flatness measurement method was introduced to overcome this prevailing feature in the available methods. The mathematical modeling for this method was also presented making the underlying nature of the method transparent. The applying examples show consistent results.
Observations of ebb flows on tidal flats: Evidence of dewatering?
Rinehimer, J. P.; Thomson, J. M.; Chickadel, C.
2010-12-01
Incised channels are a common morphological feature of tidal flats. When the flats are inundated, flows are generally forced by the tidally varying sea surface height. During low tide, however, these channels continue to drain throughout flat exposure even without an upstream source of water. While the role of porewater is generally overlooked due to the low permeability of marine muds, it remains the only potential source of flows through the channels during low tide. In situ and remotely sensed observations (Figure 1) at an incised channel on a tidal flat in Willapa Bay from Spring 2010 indicate that dewatering of the flats may be driving these low tide flows. High resolution Aquadopp ADCP velocity profiles are combined with observations from tower-based infrared (IR) video to produce a complete time series of surface velocity measurements throughout low tide. The IR video observations provide a measurement of surface currents even when the channel depth is below the blanking distance of the ADCP (10 cm). As the depth within the channel drops from 50 cm to 10 cm surface velocities increase from 10 cm/s to 60 cm/s even as the tide level drops below the channel flanks and the flats are dry. As the drainage continues, the temperature of the flow rises throughout low tide, mirroring temperatures within the sediment bed on the tidal flat. Drainage salinity falls despite the lack of any freshwater input to the flat indicating that less saline porewater may be the source. The likely source of the drainage water is from the channel flanks where time-lapse video shows slumping and compaction of channel sediments. Velocity profiles, in situ temperatures, and IR observations also are consistent with the presence of fluid muds and a hyperpycnal, density driven outflow at the channel mouth highlighting a possible pathway for sediment delivery from the flats to the main distributary channels of the bay. Figure 1: Time series of tidal flat channel velocities and temperatures
Is there a flatness problem in classical cosmology?
Helbig, Phillip
2011-01-01
I briefly review the flatness problem within the context of classical cosmology and examine some of the debate in the literature with regard to its definition and even the question whether it exists. I then present some new calculations for cosmological models which will collapse in the future; together with previous work by others for models which will expand forever, this allows one to examine the flatness problem quantitatively for all cosmological models. This leads to the conclusion that the flatness problem does not exist, not only for the cosmological models corresponding to the currently popular values of lambda_0 and Omega_0 but indeed for all Friedmann-Lema\\^itre models.
Olguin-García, María Guadalupe; Jurado-Santa Cruz, Fermín; Peralta-Pedrero, María Luisa; Morales-Sánchez, Martha Alejandra
2015-02-01
Abstract Background: Recalcitrant facial flat warts are caused by human papillomavirus and may persist for years despite treatment. Isotretinoin has demonstrated benefits in the treatment of recalcitrant, genital and common warts, but placebo-controlled trials have not been performed. To determine whether isotretinoin is safe and effective for recalcitrant facial flat warts. Isotretinoin 30 mg/day or placebo was administered to 16 and 15 patients, respectively, in double-blind, randomized fashion for 12 weeks. Cutaneous lesions were assessed and adverse events including serologic and ophthalmologic changes were recorded. It is considered that warts were recalcitrant if the patient was treated for at least 3 years with at least three of the following options: retinoids, 5-fluorouracil, imiquimod and cryotherapy using liquid nitrogen. Each patient in the istotretinoin group showed complete clearance of all flat warts, while none of the patients in the placebo group showed any improvement (p=0.0001). The most frequent adverse event was cheilitis. There were no statistically significant changes in the laboratory findings. The study design does not permit complete blinding of the dermatologist who can easily recognize the adverse effects of isotretinoin. The clinical findings, however, were so dramatic that this would not have impacted the findings. Another limitation of the study is a lack of follow-up to assess for recurrence after the drug was discontinued. Isotretinoin is an effective treatment for recalcitrant flat facial warts with a well-known, manageable safety profile.
Liu, Jiping
2015-01-01
The book drawing on the author's nearly half a century of energetic materials research experience intends to systematically review the global researches on liquid explosives. The book focuses on the study of the conception, explosion mechanism, properties and preparation of liquid explosives. It provides a combination of theoretical knowledge and practical examples in a reader-friendly style. The book is likely to be interest of university researchers and graduate students in the fields of energetic materials, blasting engineering and mining.
Software Simulates Sight: Flat Panel Mura Detection
2008-01-01
In the increasingly sophisticated world of high-definition flat screen monitors and television screens, image clarity and the elimination of distortion are paramount concerns. As the devices that reproduce images become more and more sophisticated, so do the technologies that verify their accuracy. By simulating the manner in which a human eye perceives and interprets a visual stimulus, NASA scientists have found ways to automatically and accurately test new monitors and displays. The Spatial Standard Observer (SSO) software metric, developed by Dr. Andrew B. Watson at Ames Research Center, measures visibility and defects in screens, displays, and interfaces. In the design of such a software tool, a central challenge is determining which aspects of visual function to include while accuracy and generality are important, relative simplicity of the software module is also a key virtue. Based on data collected in ModelFest, a large cooperative multi-lab project hosted by the Optical Society of America, the SSO simulates a simplified model of human spatial vision, operating on a pair of images that are viewed at a specific viewing distance with pixels having a known relation to luminance. The SSO measures the visibility of foveal spatial patterns, or the discriminability of two patterns, by incorporating only a few essential components of vision. These components include local contrast transformation, a contrast sensitivity function, local masking, and local pooling. By this construction, the SSO provides output in units of "just noticeable differences" (JND) a unit of measure based on the assumed smallest difference of sensory input detectable by a human being. Herein is the truly amazing ability of the SSO, while conventional methods can manipulate images, the SSO models human perception. This set of equations actually defines a mathematical way of working with an image that accurately reflects the way in which the human eye and mind behold a stimulus. The SSO is
Deer Flat National Wildlife Refuge: Narrative Report: 1979: Calendar Year
US Fish and Wildlife Service, Department of the Interior — This narrative report for Deer Flat National Wildlife Refuge outlines Refuge accomplishments during the 1979 calendar year. The report begins with an introduction to...
Yukon Flats National Wildlife Refuge Fishery. Management Plan
US Fish and Wildlife Service, Department of the Interior — The Yukon Flats National Wildlife Refuge Fishery Management Plan (Fishery Plan) provides comprehensive management direction to insure that fish species and habitats...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1982
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1982 calendar year. The report begins with a...
PUFFER (Pop-Up Flat Folding Explorer Robots)
Karras, J.; Carpenter, K.; Fuller, C.; Parcheta, C.
2016-10-01
PUFFER (Pop-Up Flat Folding Explorer Robots) are origami-inspired folding robots with extreme terrain mobility. PUFFERs are low-volume, low-mass, and low-cost robots for high-reward extreme terrain science.
Summary of Comprehensive Conservation Plan : Rocky Flats National Wildlife Refuge
US Fish and Wildlife Service, Department of the Interior — This document offers a summary of Rocky Flats National Wildlife Refuge's 2005 Final Comprehensive Conservation Plan. In addition to offering a brief discussion of...
Northern Mariana Islands Marine Monitoring Team Reef Flat Surveys
National Oceanic and Atmospheric Administration, Department of Commerce — The Commonwealth of the Northern Mariana Islands' (CNMI) interagency marine monitoring team conducts surveys on reef flat areas on the islands of Saipan, Tinian and...
Non-conformally flat initial data for binary compact objects
Uryu, Koji; Friedman, John L; Gourgoulhon, Eric; Shibata, Masaru
2009-01-01
A new method is described for constructing initial data for a binary neutron-star (BNS) system in quasi-equilibrium circular orbit. Two formulations for non-conformally flat data, waveless (WL) and near-zone helically symmetric (NHS), are introduced; in each formulation, the Einstein-Euler system, written in 3+1 form on an asymptotically flat spacelike hypersurface, is exactly solved for all the metric components including the spatially non-conformally flat part, and for irrotational flow. A numerical method applicable to both formulations is explained with an emphasis on the imposition of a spatial gauge condition. Results are shown for solution sequences of irrotational BNSs with matter approximated by a parametrized equations of state that uses a few segments of polytropic equations of state. WL/NHS formulations correct the results from the conformally flat -- Isenberg-Wilson-Mathews (IWM) -- formulation. Binding energy or total angular momentum of solution sequences computed within the IWM formulation are...
Higher-spin algebras, holography and flat space
Sleight, C.; Taronna, M.
2017-02-01
In this article we study the higher-spin algebra behind the type-A cubic couplings recently extracted from the free O( N ) model in generic dimensions, demonstrating that they coincide with the known structure constants for the unique higher-spin algebra in generic dimensions. This provides an explicit check of the holographic reconstruction and of the duality between higher-spin theories and the free O( N ) model in generic dimensions, generalising the result of Giombi and Yin in AdS4. For completeness, we also address the same problem in the flat space for the cubic couplings derived by Metsaev in 1991, which are recovered from the flat limit of the AdS type-A cubic couplings. We observe that both flat and AdS4 higher-spin Lorentz subalgebras coincide, hinting towards the existence of a full higher-spin symmetry behind the flat-space cubic couplings of Metsaev.
The Ricci Curvature of Half-flat Manifolds
Ali, T; Ali, Tibra; Cleaver, Gerald B.
2007-01-01
We derive expressions for the Ricci curvature tensor and scalar in terms of intrinsic torsion classes of half-flat manifolds by exploiting the relationship between half-flat manifolds and non-compact $G_2$ holonomy manifolds. Our expressions are tested for Iwasawa and more general nilpotent manifolds. We also derive expressions, in the language of Calabi-Yau moduli spaces, for the torsion classes and the Ricci curvature of the \\emph{particular} half-flat manifolds that arise naturally via mirror symmetry in flux compactifications. Using these expressions we then derive a constraint on the K\\"ahler moduli space of type II string theory on these half-flat manifolds.
Modified Ricci flow and asymptotically non-flat spaces
Chatterjee, Shubhayu
2013-01-01
The present work extends the application of a modified Ricci flow equation to an asymptotically non flat space, namely Marder's cylindrially symmetric space. It is found that the flow equation has a solution at least in a particular case.
Multiscale flat norm signatures for shapes and images
Sandine, Gary [Los Alamos National Laboratory; Morgan, Simon P [Los Alamos National Laboratory; Vixie, Kevin R [WASHINGTON STATE UNIV.; Clawson, Keth [WASHINGTON STATE UNIV.; Asaki, Thomas J [WASHINGTON STATE UNIV.; Price, Brandon [WALLA WALLA UNIV.
2009-01-01
In this paper we begin to explore the application of the multiscale flat norm introduced in Morgan and Vixie to shape and image analysis. In particular, we look at the use of the multiscale flat norm signature for the identification of shapes. After briefly reviewing the multiscale flat norm, the L{sup 1}TV functional and the relation between these two, we introduce multiscale signatures that naturally follow from the multiscale flat norm and its components. A numerical method based on the min-cut, max-flow graph-cut is briefly recalled. We suggest using L{sup 2} minimization, rather than the usual Crofton's formula based approximation, for choosing the required weights. The resulting weights have the dual benefits of being analytically computable and of giving more accurate approximations to the anisotropic TV energy. Finally, we demonstrate the usefulness of the signatures on simple shape classification tasks.
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1992
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1992 calendar year. The report begins with a summary...
Flexural Behavior of Posttensioned Flat Plates Depending on Tendon Layout
Min Sook Kim
2016-01-01
Full Text Available This paper discusses the experimental results on the flexural behavior and deflections of posttensioned concrete flat plates depending on tendon layout. One reinforced concrete flat plate and two posttensioned concrete flat plates were manufactured and tested. One-way posttensioning layout and two-way posttensioning layout were considered in this paper. The load-deflection behavior and modes of crack are presented from the test results. Posttension systems effectively controlled crack and deflection. One-way and two-way posttensioning layouts both showed similar maximum load. However, serviceability improved with two-way posttensioning layout compared to one-way posttensioning layout. Also, the yield-line theory was applied to predict the ultimate load for the posttensioned flat plates. The comparison between the test results and estimation by yield-line analysis generally showed good agreement.
Landau-Zener Bloch Oscillations with Perturbed Flat Bands.
Khomeriki, Ramaz; Flach, Sergej
2016-06-17
Sinusoidal Bloch oscillations appear in band structures exposed to external fields. Landau-Zener (LZ) tunneling between different bands is usually a counteracting effect limiting Bloch oscillations. Here we consider a flat band network with two dispersive and one flat band, e.g., for ultracold atoms and optical waveguide networks. Using external synthetic gauge and gravitational fields we obtain a perturbed yet gapless band structure with almost flat parts. The resulting Bloch oscillations consist of two parts-a fast scan through the nonflat part of the dispersion structure, and an almost complete halt for substantial time when the atomic or photonic wave packet is trapped in the original flat band part of the unperturbed spectrum, made possible due to LZ tunneling.
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1983
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1983 calendar year. The report begins with a summary...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1989
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1989 calendar year. The report begins with a summary...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1987
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1987 calendar year. The report begins with a summary...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1984
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1984 calendar year. The report begins with a summary...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1988
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1988 calendar year. The report begins with a summary...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1985
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1985 calendar year. The report begins with a summary...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1986
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1986 calendar year. The report begins with a summary...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1998
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1998 calendar year. The report begins with a summary...
Interacting tachyon dark energy in non-flat universe
Setare, M.R.; Sadeghi, J.; Amani, A R
2009-01-01
In this paper we study the tachyon cosmology in non-interacting and interacting cases in non-flat FRW universe. Then we reconstruct the potential and the dynamics of the tachyon field which describe tachyon cosmology.
BTZ extensions of globally hyperbolic singular flat spacetimes
Brunswic, Léo
2016-01-01
Minkowski space is the local model of 3 dimensionnal flat spacetimes. Recent progress in the description of globally hyperbolic flat spacetimes showed strong link between Lorentzian geometry and Teichm{\\"u}ller space. We notice that Lorentzian generalisations of conical singularities are useful for the endeavours of descripting flat spacetimes, creating stronger links with hyperbolic geometry and compactifying spacetimes. In particular massive particles and extreme BTZ singular lines arise naturally. This paper is three-fold. First, prove background local properties which will be useful for future work. Second, generalise fundamental theorems of the theory of globally hyperbolic flat spacetimes. Third, defining BTZ-extension and proving it preserves Cauchy-maximality and Cauchy-completeness.
Svendsen Symphony No. 2 in B flat / Robert Layton
Layton, Robert
1994-01-01
Uuest heliplaadist "Svendsen Symphony No. 2 in B flat, Op. 15... Stavanger Symphony Orchestra / Grant Llewellyn. Chatsworth CD FCM 1002; Symphony No. 2 - selected comparisons: Gothenburg SO, Järvi (11/87)(BIS) CD 347
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1991
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1991 calendar year. The report begins with a summary...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1990
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1990 calendar year. The report begins with a summary...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1997
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1997 calendar year. The report begins with a summary...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1993
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1993 calendar year. The report begins with a summary...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1996
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1996 calendar year. The report begins with a summary...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 2001
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 2001 calendar year. The report begins with a summary...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 2000
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 2000 calendar year. The report begins with a summary...
Inventory and Monitoring Plan for Yukon Flats National Wildlife Refuge
US Fish and Wildlife Service, Department of the Interior — This IMP prioritizes and describes the inventory, monitoring, and research surveys to be conducted on the Yukon Flats NWR over the next 10 years, based on guidance...
Material Flow Modification in a FSW Through Introduction of Flats
Schneider, Judy; Brooke, Shane; Nunes, Arthur C.
2016-02-01
Friction stir welding (FSW) is a solid-state process in which a non-consumable weld tool is used to stir metal together to obtain a fully consolidated weld seam. There is controversy regarding the contributions of various attributes of the pin design, especially with regards to flats and flutes. In this study, similar FSWs made with threaded cylindrical pin-tools having 0, 1, 2, 3, 4, and 5 flats were compared. Slight increases in torque were noted with increasing flats. Significant changes in the FSW structure with varying numbers of flats were observed, but without significant changes in tensile strength. Changes in the textural banding shape, the addition of sub-bands, and a new set of bands from coalescence of band kinks constitute the structural changes observed. Explanations of these structural changes in terms of tool interactions with the FSW metal are offered.
Svendsen Symphony No. 2 in B flat / Robert Layton
Layton, Robert
1994-01-01
Uuest heliplaadist "Svendsen Symphony No. 2 in B flat, Op. 15... Stavanger Symphony Orchestra / Grant Llewellyn. Chatsworth CD FCM 1002; Symphony No. 2 - selected comparisons: Gothenburg SO, Järvi (11/87)(BIS) CD 347
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1981
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1981 calendar year. The report begins with a summary...
Quaternary geology of Fish Springs flat, Juab county, Utah
US Fish and Wildlife Service, Department of the Interior — Fish Springs Flat is a sediment-filled valley between two tilted mountain blocks, the Thomas Range and the Fish Springs Range, in the Basin and Range physiographic...
Yukon Flats National Wildlife Refuge : Narrative Report : Calendar Year 1994
US Fish and Wildlife Service, Department of the Interior — This annual narrative report for Yukon Flats National Wildlife Refuge outlines Refuge accomplishments during the 1994 calendar year. The report begins with a summary...
Analysis of flat slab building with and without shear wall
Dhanaji R. Chavan; Mohite D. D.; Dr. C. P. Pise; Pawar Y. P; Kadam S.S.; Deshmukh C. M.
2016-01-01
The analytical research carried out to study the behaviour flat slab building with and without shear wall reported in the present work. For analysis 15 storied flat slab building is analyzed for seismic behaviour. Response spectrum method is used for analysis considering different shear wall positions using ETABS software. Five different positions of shear wall were studied for analysis. From this analysis shear wall at core having square shape is most suitable case for construction of shear ...
Deformation analysis of optical flat surface with finite element method
Fu, Pengqiang; Ren, Boyuan; Wang, Yiwen; Zhang, Dewei; Zhang, Longjiang; Su, Xing
2016-10-01
Proposing a new method for testing the ultra-precision aerostatic spindle motion accuracy based on analyzing the online real-time dynamic interference image. Optical flat crystal as the testing standard will be installed at the end of the ultra precision aerostatic spindle and will motion along with the spindle. On the other end of the spindle, the tool will be installed for online processing. The image data of optical flat crystal collected by the high-precision dynamic interferometer will be processed for analyzing the spindle error. For collecting higher accuracy image data, the installation way of optical flat crystal is one of the key technologies. Base on this, the effects of the clamping means on the surface accuracy of optical flat crystal is studied. At first, the finite element model of the optical flat crystal`s clamping structure were established. Secondly, the influence of the material of the supporting annulus, preload lateral clamping and spindle speed on the surface accuracy of optical flat crystal had been analyzed. At last, the improved and optimized structure of the optical flat crystal has been presented. As the analysis results shown, the RMS value of reference surface is 9.47nm and the deformation values of the central region is 0.17nm which satisfies the requirement of surface accuracy and installation of optical flat crystal. It has a very important theoretical and practical significance to establish spindle online testing system and research rotary error generating mechanism of ultra-precision spindle to improve surface accuracy of ultra-precision machining.
Trajectory tracking for robot manipulators using differential flatness
Elkin Veslin Diaz
2011-05-01
Full Text Available This paper proposes applying differential flatness to robot manipulator trajectory tracking. The trajectories for each generalised coordinate are proposed as a function and the corresponding input must be found to guarantee tracking. It is shown that the position in the generalised coordinates and their derivatives are flat inputs which, together with a PD controller, could determine (with some restrictions manipulator movement having minimal deviation throughout its trajectory in both plane movements and in space.
Analysis of flat slab building with and without shear wall
Dhanaji R. Chavan
2016-10-01
Full Text Available The analytical research carried out to study the behaviour flat slab building with and without shear wall reported in the present work. For analysis 15 storied flat slab building is analyzed for seismic behaviour. Response spectrum method is used for analysis considering different shear wall positions using ETABS software. Five different positions of shear wall were studied for analysis. From this analysis shear wall at core having square shape is most suitable case for construction of shear wall.
Analysis of Flat-Plate Solar Array and Solar Lantern
P. L. N. V. Aashrith
2014-05-01
Full Text Available A very detailed theortical analysis of a solar array has been carried out based on established values of solar radiation data to predict the performance of solar lamp . The analysis is based on established theory about flat-plate collectors. Top heat loss coefficient (Ut, Bottom heat loss coefficient (Ub, Overall heat loss coefficient (Ul, Useful energy (Qu, efficiency (hp of the flat-plate solar array and efficiency (hl of the solar lantern has been calculated.
Flat rotation curves using scalar-tensor theories
Cervantes-Cota, Jorge L.; Rodriguez-Meza, M. A.; Nunez, Dario
2007-01-01
We computed flat rotation curves from scalar-tensor theories in their weak field limit. Our model, by construction, fits a flat rotation profile for velocities of stars. As a result, the form of the scalar field potential and DM distribution in a galaxy are determined. By taking into account the constraints for the fundamental parameters of the theory $(\\lambda, \\alpha)$, it is possible to obtain analytical results for the density profiles. For positive and negative values of $\\alpha$, the DM...
How to produce flat slabs: insights from numeric modeling
Constantin Manea, Vlad; Perez-Gussinye, Marta; Manea, Marina
2010-05-01
Flat slab subduction occurs at ~10% of the active convergent margins and it is assumed that subduction of oceanic aseismic ridges or seamount chains is the main mechanism to produce very low angle subduction slabs. However, recent numeric and analog modeling showed that ridges alone of moderate dimensions subducted perpendicular to the trench are not sufficient to produce flat-slab geometries. Therefore an alternative mechanism able to produce flat-slabs is required. In this paper we present dynamic numeric modeling results of subduction in the vicinity of thick continental lithosphere, as a craton for example. We tailored our modeling setup for the Chilean margins at ~31° and our models are integrated back in time 30 Myr. Modeling results show that a craton thickness of 200 km or more when approaching the trench is capable of blocking the asthenospheric flow in the mantle wedge and increasing considerably the suction force. We were able to produce a flat slab that fits well the flat slab geometry in Chile (based on seismicity) and stress distribution. We conclude that thick cratons located in the vicinity of subduction zones, are capable to produce very low angle slabs, and probable a combination of buoyant ridge subduction with a neighbor thick craton represent a better mechanism to produce flat slabs.
Flat-panel volume CT: fundamental principles, technology, and applications.
Gupta, Rajiv; Cheung, Arnold C; Bartling, Soenke H; Lisauskas, Jennifer; Grasruck, Michael; Leidecker, Christianne; Schmidt, Bernhard; Flohr, Thomas; Brady, Thomas J
2008-01-01
Flat-panel volume computed tomography (CT) systems have an innovative design that allows coverage of a large volume per rotation, fluoroscopic and dynamic imaging, and high spatial resolution that permits visualization of complex human anatomy such as fine temporal bone structures and trabecular bone architecture. In simple terms, flat-panel volume CT scanners can be thought of as conventional multidetector CT scanners in which the detector rows have been replaced by an area detector. The flat-panel detector has wide z-axis coverage that enables imaging of entire organs in one axial acquisition. Its fluoroscopic and angiographic capabilities are useful for intraoperative and vascular applications. Furthermore, the high-volume coverage and continuous rotation of the detector may enable depiction of dynamic processes such as coronary blood flow and whole-brain perfusion. Other applications in which flat-panel volume CT may play a role include small-animal imaging, nondestructive testing in animal survival surgeries, and tissue-engineering experiments. Such versatility has led some to predict that flat-panel volume CT will gain importance in interventional and intraoperative applications, especially in specialties such as cardiac imaging, interventional neuroradiology, orthopedics, and otolaryngology. However, the contrast resolution of flat-panel volume CT is slightly inferior to that of multidetector CT, a higher radiation dose is needed to achieve a comparable signal-to-noise ratio, and a slower scintillator results in a longer scanning time.
[Flat-panel detectors in X-ray systems].
Spahn, M; Heer, V; Freytag, R
2003-05-01
For all application segments X-ray systems with flat-panel detectors increasingly enter the market. In digital radiography,mammography and cardiologic angiography flat-panel detectors are already well established while they are made ready for market introduction in general angiography and fluoroscopy. Two flat-panel detector technologies are available. One technology is based on an indirect conversion process of X-rays while the other one uses a direct conversion method. For radiography and dynamic applications the indirect method provides substantial advantages, while the direct method has some benefits for mammography. In radiography and mammography flat-panel detectors lead to clear improvements with respect to workflow, image quality and dose reduction potentials. These improvements are fostered by the immediate availability of the image, the large dynamic range and the high sensitivity to X-rays. New applications and the use of complex image processing algorithms have the potential to enlarge the present diagnostic range of applications. Up to now, image intensifiers are still the well-established technology for angiography and fluoroscopy. Nevertheless flat-panel detectors begin to enter this field, especially in cardiologic angiography. Characteristics of flat-panel detectors such as the availability of distortion-free images, the excellent contrast resolution, the large dynamic range, the high sensitivity to X-rays and the usability in magnetic fields provide the basis for improved and new diagnostic and interventional methods.
Flatness-based pre-compensation of laser diodes
Rouchon, A Abichou S Elasmi P
2007-01-01
A physical nonlinear dynamical model of a laser diode is considered. We propose a feed-forward control scheme based on differential flatness for the design of input-current modulations to compensate diode distortions. The goal is to transform without distortion a radio-frequency current modulation into a light modulation leaving the laser-diode and entering an optic fiber. We prove that standard physical dynamical models based on dynamical electron and photons balance are flat systems when the current is considered as control input, the flat output being the photon number (proportional to the light power). We prove that input-current is an affine map of the flat output, its logarithm and their time-derivatives up to order two. When the flat output is an almost harmonic signal with slowly varying amplitude and phase, these derivatives admit precise analytic approximations. It is then possible to design simple analogue electronic circuits to code approximations of the nonlinear computations required by our flat...
1990-01-01
Thermochromic liquid crystals, or TLCs, are a type of liquid crystals that react to changes in temperature by changing color. The Hallcrest/NASA collaboration involved development of a new way to visualize boundary layer transition in flight and in wind tunnel testing of aircraft wing and body surfaces. TLCs offered a new and potentially better method of visualizing the boundary layer transition in flight. Hallcrest provided a liquid crystal formulation technique that afforded great control over the sensitivity of the liquid crystals to varying conditions. Method is of great use to industry, government and universities for aerodynamic and hydrodynamic testing. Company's principal line is temperature indicating devices for industrial use, such as non-destructive testing and flaw detection in electric/electronic systems, medical application, such as diagnostic systems, for retail sale, such as room, refrigerator, baby bath and aquarium thermometers, and for advertising and promotion specials. Additionally, Hallcrest manufactures TLC mixtures for cosmetic applications, and liquid crystal battery tester for Duracell batteries.
THE FLAT TAX - A COMPARATIVE STUDY OF THE EXISTING MODELS
Schiau (Macavei Laura - Liana
2011-07-01
Full Text Available In the two last decades the flat tax systems have spread all around the globe from East and Central Europe to Asia and Central America. Many specialists consider this phenomenon a real fiscal revolution, but others see it as a mistake as long as the new systems are just a feint of the true flat tax designed by the famous Stanford University professors Robert Hall and Alvin Rabushka. In this context this paper tries to determine which of the existing flat tax systems resemble the true flat tax model by comparing and contrasting their main characteristics with the features of the model proposed by Hall and Rabushka. The research also underlines the common features and the differences between the existing models. The idea of this kind of study is not really new, others have done it but the comparison was limited to one country. For example Emil Kalchev from New Bulgarian University has asses the Bulgarian income system, by comparing it with the flat tax and concluding that taxation in Bulgaria is not simple, neutral and non-distortive. Our research is based on several case studies and on compare and contrast qualitative and quantitative methods. The study starts form the fiscal design drawn by the two American professors in the book The Flat Tax. Four main characteristics of the flat tax system were chosen in order to build the comparison: fiscal design, simplicity, avoidance of double taxation and uniformity of the tax rates. The jurisdictions chosen for the case study are countries all around the globe with fiscal systems which are considered flat tax systems. The results obtained show that the fiscal design of Hong Kong is the only flat tax model which is built following an economic logic and not a legal sense, being in the same time a simple and transparent system. Others countries as Slovakia, Albania, Macedonia in Central and Eastern Europe fulfill the requirement regarding the uniformity of taxation. Other jurisdictions avoid the double
M. Cerza; R.C. Herron; J.J. Harper
2002-06-24
An experimental facility for conducting research on capillary pumped loop (CPL) systems was developed. In order to simulate shipboard cooling water encountered at various locations of the ocean, the heat sink temperature of the facility could be varied. A flat plate, CPL evaporator was designed and tested under various heat sink temperatures. The sink temperature ranged from 274.3 to 305.2 K and the heat input varied from 250 to 800 W which corresponds to heat fluxes up to 1.8 W/cm{sup 2}. The CPL flat plate evaporator performed very well under this range of heat input and sink temperatures. The main result obtained showed that a large degree of subcooling developed between the evaporator vapor outlet line and liquid return line. This condensate depression increased with increasing heat input.
Bird, James C
2008-01-01
We experiment with injecting a continuous stream of gas into a shallow liquid, similar to how one might blow into a straw placed at the bottom of a near-empty drink. By varying the angle of the straw (here a metal needle), we observe a variety of dynamics, which we film using a high-speed camera. Most noteworthy is an intermediate regime in which cyclical jets erupt from the air-liquid interface and breakup into air-born droplets. These droplets trace out a parabolic trajectory and bounce on the air-liquid interface before eventually coalescing. The shape of each jet, as well as the time between jets, is remarkably similar and leads to droplets with nearly identical trajectories. The following article accompanies the linked fluid dynamics video submitted to the Gallery of Fluid Motion in 2008.
Safinya, C.R.; Safran, S.A. (Exxon Research and Engineering Co., Annandale, NJ (US)); Pincus, P.A. (Univ. of California at Santa Barbara, Santa Barbara, CA (US))
1990-01-01
Liquids include a broad range of material systems which are of high scientific and technological interest. Generally speaking, these are partially ordered or disordered phases where the individual molecular species have organized themselves on length scales which are larger than simple fluids, typically between 10 Angstroms and several microns. The specific systems reported on in this book include membranes, microemulsions, micelles, liquid crystals, colloidal suspensions, and polymers. They have a major impact on a broad spectrum of technological industries such as displays, plastics, soap and detergents, chemicals and petroleum, and pharmaceuticals.
Experimental data showing the thermal behavior of a flat roof with phase change material
Ayça Tokuç
2015-12-01
Full Text Available The selection and configuration of building materials for optimal energy efficiency in a building require some assumptions and models for the thermal behavior of the utilized materials. Although the models for many materials can be considered acceptable for simulation and calculation purposes, the work for modeling the real time behavior of phase change materials is still under development. The data given in this article shows the thermal behavior of a flat roof element with a phase change material (PCM layer. The temperature and energy given to and taken from the building element are reported. In addition the solid–liquid behavior of the PCM is tracked through images. The resulting thermal behavior of the phase change material is discussed and simulated in [1] A. Tokuç, T. Başaran, S.C. Yesügey, An experimental and numerical investigation on the use of phase change materials in building elements: the case of a flat roof in Istanbul, Build. Energy, vol. 102, 2015, pp. 91–104.
Measurement of Coolant in a Flat Heat Pipe Using Neutron Radiography
Mizuta, Kei; Saito, Yasushi; Goshima, Takashi; Tsutsui, Toshio
A newly developed flat heat pipe FGHPTM (Morex Kiire Co.) was experimentally investigated by using neutron radiography. The test sample of the FGHP heat spreader was 65 × 65 × 2 mm3 composed of several etched copper plates and pure water was used as the coolant. Neutron radiography was performed at the E-2 port of the Kyoto University Research Reactor (KUR). The coolant distributions in the wick area of the FGHP and its heat transfer characteristics were measured at heating conditions. Experimental results show that the coolant distributions depend slightly on its installation posture and that the liquid thickness in the wick region remains constant with increasing heat input to the FGHP. In addition, it is found that the wick surface does not dry out even in the vertical posture at present experimental conditions.
Wettability-independent bouncing on flat surfaces mediated by thin air films
de Ruiter, Jolet; Lagraauw, Rudy; van den Ende, Dirk; Mugele, Frieder
2015-01-01
The impingement of drops onto solid surfaces plays a crucial role in a variety of processes, including inkjet printing, fog harvesting, anti-icing, dropwise condensation and spray coating. Recent efforts in understanding and controlling drop impact behaviour focused on superhydrophobic surfaces with specific surface structures enabling drop bouncing with reduced contact time. Here, we report a different universal bouncing mechanism that occurs on both wetting and non-wetting flat surfaces for both high and low surface tension liquids. Using high-speed multiple-wavelength interferometry, we show that this bouncing mechanism is based on the continuous presence of an air film for moderate drop impact velocities. This submicrometre `air cushion' slows down the incoming drop and reverses its momentum. Viscous forces in the air film play a key role in this process: they provide transient stability of the air cushion against squeeze-out, mediate momentum transfer, and contribute a substantial part of the energy dissipation during bouncing.
Numerical analysis on thermal hydraulic performance of a flat plate heat pipe with wick column
Lu, Longsheng; Liao, Huosheng; Liu, Xiaokang; Tang, Yong
2015-08-01
A simplified thermal hydraulic model is developed to investigate the influence of wick column on the performance of a flat plate heat pipe (FPHP). The governing equations of the FPHP are solved by using the computational fluid dynamics package FLUENT. The temperature, velocity and pressure fields are obtained. The validity of the model is confirmed by comparing the present solutions with the open literature data. The numerical results show that with the increase of the wick column size, the maximum velocity of the liquid and vapor decreases while the total thermal resistance and capillary heat transfer limit of the FPHP increases gradually. The performance of the FPHP may degrade if the wick column is placed inside the vapor core asymmetrically.
Khalil, Kareem
2012-12-01
Granulation, the process of formation of granules from a combination of base powders and binder liquids, has been a subject of research for almost 50 years, studied extensively for its vast applications, primarily to the pharmaceutical industry sector. The principal aim of granulation is to form granules comprised of the active pharmaceutical ingredients (API’s), which have more desirable handling and flowability properties than raw powders. It is also essential to ensure an even distribution of active ingredients within a tablet with the goal of achieving time‐controlled release of drugs. Due to the product‐specific nature of the industry, however, data is largely empirical [1]. For example, the raw powders used can vary in size by two orders of magnitude with narrow or broad size distributions. The physical properties of the binder liquids can also vary significantly depending on the powder properties and required granule size. Some significant progress has been made to better our understanding of the overall granulation process [1] and it is widely accepted that the initial nucleation / wetting stage, when the binder liquid first wets the powders, is key to the whole process. As such, many experimental studies have been conducted in attempt to elucidate the physics of this first stage [1], with two main mechanisms being observed – classified by Ivenson [1] as the “Traditional description” and the “Modern Approach”. See Figure 1 for a graphical definition of these two mechanisms. Recent studies have focused on the latter approach [1] and a new, exciting development in this field is the Liquid Marble. This interesting formation occurs when a liquid droplet interacts with a hydrophobic (or superhydrophobic) powder. The droplet can become encased in the powder, which essentially provides a protective “shell” or “jacket” for the liquid inside [2]. The liquid inside is then isolated from contact with other solids or liquids and has some
Supported liquid membranes technologies in metals removal from liquid effluents
de Agreda, D.
2011-04-01
Full Text Available The generation of liquid effluents containing organic and inorganic residues from industries present a potential hazardousness for environment and human health, being mandatory the elimination of these pollutants from the respective solutions containing them. In order to achieve this goal, several techniques are being used and among them, supported liquid membranes technologies are showing their potential for their application in the removal of metals contained in liquid effluents. Supported liquid membranes are a combination between conventional polymeric membranes and solvent extraction. Several configurations are used: flat-sheet supported liquid membranes, spiral wounds and hollow fiber modules. In order to improve their effectiveness, smart operations have been developed: non-dispersive solvent extraction, non-dispersive solvent extraction with strip phase dispersion and hollow fiber renewal liquid membrane. This paper overviewed some of these supported liquid membranes technologies and their applications to the treatment of metal-bearing liquid effluents.
La generación, por parte de las industrias, de efluentes líquidos conteniendo sustancias orgánicas e inorgánicas, es un peligro potencial tanto para los humanos como para el medio ambiente, siendo necesaria la eliminación de estos elementos tóxicos de las disoluciones que los contienen. Para conseguir este fin, se están aplicando diversas técnicas y entre ellas las tecnologías de membranas líquidas soportadas, están demostrando sus aptitudes para la eliminación de metales contenidos en efluentes líquidos. Las membranas líquidas soportadas, resultan de la unión de las membranas poliméricas y de la tecnología de extracción líquido-líquido. Este tipo de membranas se pueden utilizar en diversas configuraciones: plana, módulo en fibra hueca y módulo en espiral y para aumentar su efectividad se están desarrollando las llamadas operaciones avanzadas: extracción no
Study of role of meniscus and viscous forces during liquid-mediated contacts separation
Dhital, Prabin
Menisci may form between two solid surfaces with the presence of an ultra-thin liquid film. When the separation operation is needed, meniscus and viscous forces contribute to an adhesion leading stiction, high friction, possibly high wear and potential failure of the contact systems, for instance microdevices, magnetic head disks and diesel fuel injectors. The situation may become more pronounced when the contacting surfaces are ultra-smooth and the normal load is small. Various design parameters, such as contact angle, initial separation height, surface tension and liquid viscosity, have been investigated during liquid-mediated contact separation. However, how the involved forces will change roles for various liquid is of interest and is necessary to be studied. In this study, meniscus and viscous forces due to water and liquid lubricants during separation of two flat surfaces are studied. Previously established mathematical model for meniscus and viscous forces during flat on flat contact separation is simulated. The effect of meniscus and viscous force on critical meniscus area at which those forces change role is studied with different liquid properties for flat on flat contact surfaces. The roles of the involved forces at various meniscus areas are analyzed. Experiments are done in concerns to studying the effect of surface roughness on contact angle. The impact of liquid properties, initial separation heights and contact angle on critical meniscus area for different liquid properties are analyzed. The study provides a fundamental understanding of the forces of the separation process and its value for the design of interfaces. The effect of surface roughness and liquid properties on contact angle are studied.
Flexible flat feet in children: a real problem?
García-Rodríguez, A; Martín-Jiménez, F; Carnero-Varo, M; Gómez-Gracia, E; Gómez-Aracena, J; Fernández-Crehuet, J
1999-06-01
To estimate the prevalence of flexible flat feet in the provincial population of 4- to 13-year-old schoolchildren and the incidence of treatments considered unnecessary. Province of Málaga, Spain. We examined and graded by severity a sample of 1181 pupils taken from a total population of 198 858 primary schoolchildren (CI: 95%; margin of error: 5%). The sample group was separated into three 2-year age groups: 4 and 5 years, 8 and 9 years, and 12 and 13 years. The plantar footprint was classified according to Denis1 into three grades of flat feet: grade 1 in which support of the lateral edge of the foot is half that of the metatarsal support; grade 2 in which the support of the central zone and forefoot are equal; and grade 3 in which the support in the central zone of the foot is greater than the width of the metatarsal support. The statistical analysis for the evaluation of the differences between the groups was performed with Student's t and chi2 tests as appropriate. The prevalence of flat feet was 2.7%. Of the 1181 children sampled, 168 children (14.2%) were receiving orthopedic treatment, but only 2.7% had diagnostic criteria of flat feet. When we inspected the sample, we found that a number of children were being treated for flat feet with boots and arch supports. Most of them did not have a flat plantar footprint according to the criteria that we used for this work. Furthermore, in the group of children that we diagnosed as having flat feet, only 28.1% were being treated. We found no significant differences between the number of children receiving orthopedic treatments and the presence or absence of a flat plantar footprint. Children who were overweight in the 4- and 5-year-old group showed an increased prevalence for flat feet as diagnosed by us. The data suggest that an excessive number of orthopedic treatments had been prescribed in the province. When extrapolated to the 1997 population of schoolchildren within the age groups studied the figures
Griffin, Lucy R; Browning, Kathryn L; Clarke, Stuart M; Smith, Alexander M; Perkin, Susan; Skoda, M W A; Norman, Sarah E
2016-12-21
The layering of ionic liquids close to flat, charged interfaces has been identified previously through theoretical and some experimental measurements. Here we present evidence for oscillations in ion density ('layering') in a long chain ionic liquid (1-decyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide) near the interface with mica using two complementary approaches. Neutron reflection at the ionic liquid-mica interface is used to detect structure at a single interface, and surface force balance (SFB) measurements carried out with the same ionic liquid reveal oscillatory density in the liquid confined between two mica sheets. Our findings imply the interfacial structure is not induced by confinement alone. Structural forces between two mica surfaces extend to approximately twice the distance of the density oscillations measured at a single interface and have similar period in both cases.
Relationship between flexible flat foot and developmental hip dysplasia.
Ponce de León Samper, M C; Herrera Ortiz, G; Castellanos Mendoza, C
2015-01-01
To evaluate the possible relationship between flexible flat foot and developmental hip dysplasia in children between six and 15 years of age. Cross-sectional study including 65 patients that had undergone surgery due to residual hip dysplasia or hip dislocation and compared against 75 healthy patients. Flexible flat foot prevalence was measured in each group, with the results showing that 61% of the group with residual hip dysplasia or hip dislocation had this condition, vs. 12% in the healthy group. The statistical analysis shows that the chances of suffering from flexible flat foot, are five times greater in the hip dysplasia or hip dislocation group, than in the healthy group. There is no evidence in the literature showing a relationship between these two conditions, even though they have a common etiology. This study shows a potential measurable relation between this two conditions. Patients with hip dysplasia or dislocation may have a higher chance of presenting flexible flat foot during late childhood, adolescence and adulthood, a fact that suggests a relationship between these two pathologies. Also, patients who seek assistance for the first time because of a flexible flat foot condition without having been evaluated during the first year of life for hip dysplasia, would be better off if evaluated for residual hip dysplasia. Copyright © 2014 SECOT. Published by Elsevier Espana. All rights reserved.
Mussel beds are biological power stations on intertidal flats
Engel, Friederike G.; Alegria, Javier; Andriana, Rosyta; Donadi, Serena; Gusmao, Joao B.; van Leeuwe, Maria A.; Matthiessen, Birte; Eriksson, Britas Klemens
2017-05-01
Intertidal flats are highly productive areas that support large numbers of invertebrates, fish, and birds. Benthic diatoms are essential for the function of tidal flats. They fuel the benthic food web by forming a thin photosynthesizing compartment in the top-layer of the sediment that stretches over the vast sediment flats during low tide. However, the abundance and function of the diatom film is not homogenously distributed. Recently, we have realized the importance of bivalve reefs for structuring intertidal ecosystems; by creating structures on the intertidal flats they provide habitat, reduce hydrodynamic stress and modify the surrounding sediment conditions, which promote the abundance of associated organisms. Accordingly, field studies show that high chlorophyll a concentration in the sediment co-vary with the presence of mussel beds. Here we present conclusive evidence by a manipulative experiment that mussels increase the local biomass of benthic microalgae; and relate this to increasing biomass of microalgae as well as productivity of the biofilm across a nearby mussel bed. Our results show that the ecosystem engineering properties of mussel beds transform them into hot spots for primary production on tidal flats, highlighting the importance of biological control of sedimentary systems.
Magnetotelluric Data, Southern Yucca Flat, Nevada Test Site, Nevada
J.M. Williams; B.D. Rodriguez, and T.H. Asch
2005-11-23
Nuclear weapons are integral to the defense of the United States. The U.S. Department of Energy, as the steward of these devices, must continue to gauge the efficacy of the individual weapons. This could be accomplished by occasional testing at the Nevada Test Site (NTS) in Nevada, northwest of Las Vegas. Yucca Flat Basin is one of the testing areas at the NTS. One issue of concern is the nature of the somewhat poorly constrained pre-Tertiary geology and its effects on ground-water flow in the area subsequent to a nuclear test. Ground-water modelers would like to know more about the hydrostratigraphy and geologic structure to support a hydrostratigraphic framework model that is under development for the Yucca Flat Corrective Action Unit (CAU). During 2003, the U.S. Geological Survey (USGS) collected and processed Magnetotelluric (MT) and Audio-magnetotelluric (AMT) data at the Nevada Test Site in and near Yucca Flat to help characterize this pre-Tertiary geology. That work will help to define the character, thickness, and lateral extent of pre-Tertiary confining units. In particular, a major goal has been to define the upper clastic confining unit (UCCU) in the Yucca Flat area. Interpretation will include a three-dimensional (3-D) character analysis and two-dimensional (2-D) resistivity model. The purpose of this report is to release the MT sounding data for Southern Yucca Flat, Profile 4, as shown in Figure 1. No interpretation of the data is included here.
Magnetotelluric Data, Central Yucca Flat, Nevada Test Site, Nevada
J.M. Williams; B.D. Rodriguez, and T.H. Asch
2005-11-23
Nuclear weapons are integral to the defense of the United States. The U.S. Department of Energy, as the steward of these devices, must continue to gauge the efficacy of the individual weapons. This could be accomplished by occasional testing at the Nevada Test Site (NTS) in Nevada, northwest of Las Vegas. Yucca Flat Basin is one of the testing areas at the NTS. One issue of concern is the nature of the somewhat poorly constrained pre-Tertiary geology and its effects on ground-water flow in the area subsequent to a nuclear test. Ground-water modelers would like to know more about the hydrostratigraphy and geologic structure to support a hydrostratigraphic framework model that is under development for the Yucca Flat Corrective Action Unit (CAU). During 2003, the U.S. Geological Survey (USGS) collected and processed Magnetotelluric (MT) and Audio-magnetotelluric (AMT) data at the Nevada Test Site in and near Yucca Flat to help characterize this pre-Tertiary geology. That work will help to define the character, thickness, and lateral extent of pre-Tertiary confining units. In particular, a major goal has been to define the upper clastic confining unit (UCCU) in the Yucca Flat area. Interpretation will include a three-dimensional (3-D) character analysis and two-dimensional (2-D) resistivity model. The purpose of this report is to release the MT sounding data for Central Yucca Flat, Profile 1, as shown in figure 1. No interpretation of the data is included here.
Magnetotelluric Data, Northern Frenchman Flat, Nevada Test Site Nevada
J.M. Williams; B.D. Rodriguez, and T. H. Asch
2005-11-23
Nuclear weapons are integral to the defense of the United States. The U.S. Department of Energy, as the steward of these devices, must continue to gauge the efficacy of the individual weapons. This could be accomplished by occasional testing at the Nevada Test Site (NTS) in Nevada, northwest of Las Vegas. Yucca Flat Basin is one of the testing areas at the NTS. One issue of concern is the nature of the somewhat poorly constrained pre-Tertiary geology and its effects on ground-water flow in the area subsequent to a nuclear test. Ground-water modelers would like to know more about the hydrostratigraphy and geologic structure to support a hydrostratigraphic framework model that is under development for the Yucca Flat Corrective Action Unit (CAU). During 2003, the U.S. Geological Survey (USGS) collected and processed Magnetotelluric (MT) and Audio-magnetotelluric (AMT) data at the Nevada Test Site in and near Yucca Flat to help characterize this pre-Tertiary geology. That work will help to define the character, thickness, and lateral extent of pre-Tertiary confining units. In particular, a major goal has been to define the upper clastic confining unit (UCCU) in the Yucca Flat area. Interpretation will include a three-dimensional (3-D) character analysis and two-dimensional (2-D) resistivity model. The purpose of this report is to release the MT sounding data for Frenchman Flat Profile 3, as shown in Figure 1. No interpretation of the data is included here.
MHD Effect of Liquid Metal Film Flows as Plasma-Facing Components
ZHANG Xiujie; XU Zengyu; PAN Chuanjie
2008-01-01
Stability of liquid metal film flow under gradient magnetic field is investigated. Three dimensional numerical simulations on magnetohydrodynamics (MHD) effect of free surface film flow were carried out, with emphasis on the film thickness variation and its surface stability. Three different MHD phenomena of film flow were observed in the experiment, namely, retardant, rivulet and flat film flow. From our experiment and numerical simulation it can be concluded that flat film flow is a good choice for plasma-facing components (PFCs)
Miller, C. G.
1980-01-01
Conceptual design for heat exchanger, utilizing two immiscible liquids with dissimilar specific gravities in direct contact, is more efficient mechanism of heat transfer than conventional heat exchangers with walls or membranes. Concept could be adapted for collection of heat from solar or geothermal sources.
Static and dynamic electrowetting of an ionic liquid in a solid/liquid/liquid system.
Paneru, Mani; Priest, Craig; Sedev, Rossen; Ralston, John
2010-06-23
A droplet of an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, bmim.BF(4)) is immersed in an immiscible liquid (n-hexadecane) and electrowetted on a flat Teflon AF1600-coated ITO electrode. The static contact angle decreases significantly when voltage is applied between the droplet and the electrode: from 145 degrees down to 50 degrees (with DC voltage) and 15 degrees (with AC voltage). The electrowetting curves (contact angle versus voltage) are similar to the ones obtained in other solid/liquid/vapor and solid/liquid/liquid systems: symmetric with respect to zero voltage and correctly described by Young-Lippmann equation below saturation. The reversibility is excellent and contact angle hysteresis is minimal (approximately 2 degrees). The step size used in applying the DC voltage and the polarity of the voltage are unimportant. The saturation contact angle cannot be predicted with the simple zero-interfacial tension theory. Spreading (after applying a DC voltage) and retraction (after switching off the voltage) of the droplet is monitored. The base area of the droplet varies exponentially during wetting (exponential saturation) and dewetting (exponential decay). The characteristic time is 20 ms for spreading and 35 ms for retraction (such asymmetry is not observed with water-glycerol mixtures of a similar viscosity). The spreading kinetics (dynamic contact angle versus contact line speed) can be described by the hydrodynamic model (Voinov's equation) for small contact angles and by the molecular-kinetic model (Blake's equation) for large contact angles. The role of viscous and molecular dissipation follows the scheme outlined by Brochard-Wyart and de Gennes.
Weyl-Euler-Lagrange Equations of Motion on Flat Manifold
Zeki Kasap
2015-01-01
Full Text Available This paper deals with Weyl-Euler-Lagrange equations of motion on flat manifold. It is well known that a Riemannian manifold is said to be flat if its curvature is everywhere zero. Furthermore, a flat manifold is one Euclidean space in terms of distances. Weyl introduced a metric with a conformal transformation for unified theory in 1918. Classical mechanics is one of the major subfields of mechanics. Also, one way of solving problems in classical mechanics occurs with the help of the Euler-Lagrange equations. In this study, partial differential equations have been obtained for movement of objects in space and solutions of these equations have been generated by using the symbolic Algebra software. Additionally, the improvements, obtained in this study, will be presented.
Rigidity of complete noncompact bach-flat n-manifolds
Chu, Yawei; Feng, Pinghua
2012-11-01
Let (Mn,g) be a complete noncompact Bach-flat n-manifold with the positive Yamabe constant and constant scalar curvature. Assume that the L2-norm of the trace-free Riemannian curvature tensor R∘m is finite. In this paper, we prove that (Mn,g) is a constant curvature space if the L-norm of R∘m is sufficiently small. Moreover, we get a gap theorem for (Mn,g) with positive scalar curvature. This can be viewed as a generalization of our earlier results of 4-dimensional Bach-flat manifolds with constant scalar curvature R≥0 [Y.W. Chu, A rigidity theorem for complete noncompact Bach-flat manifolds, J. Geom. Phys. 61 (2011) 516-521]. Furthermore, when n>9, we derive a rigidity result for R<0.
Flat acoustic lens by acoustic grating with curled slits
Peng, Pai; Xiao, Bingmu; Wu, Ying, E-mail: ying.wu@kaust.edu.sa
2014-10-03
We design a flat sub-wavelength lens that can focus acoustic wave. We analytically study the transmission through an acoustic grating with curled slits, which can serve as a material with tunable impedance and refractive index for acoustic waves. The effective parameters rely on the geometry of the slits and are independent of frequency. A flat acoustic focusing lens by such acoustic grating with gradient effective refractive index is designed. The focusing effect is clearly observed in simulations and well predicted by the theory. We demonstrate that despite the large impedance mismatch between the acoustic lens and the matrix, the intensity at the focal point is still high due to Fabry–Perot resonance. - Highlights: • Expression of transmission coefficient of an acoustic grating with curled slits. • Non-dispersive and tunable effective medium parameters for the acoustic grating. • A flat acoustic focusing lens with gradient index by using the acoustic grating.
Plutonium and americium contamination in Rocky Flats soil, 1973
Krey, P.; Hardy, E.; Volchok, H.; Toonkel, L.; Knuth, R.; Coppes, M.; Tamura, T.
1976-03-01
The plutonium mass isotopic analysis and the Am-241 analysis of soil samples from Rocky Flats identify the contamination as Pu which was processed in 1958. The Am-241 activity in the soil will reach its maximum in 2033 and represent 18 percent of the Pu-239-240 activity. Nuclide ratios indicate that current operations at Rocky Flats contribute little to the airborne Pu concentrations which are due to resuspension of the contaminated soil. Root uptake of Pu or Am by vegetation is slight or shows no discrimination among the isotopes and nuclides studied. The relationship between Pu deposition contour and the area enclosed by that contour has been verified for contour values extending over 7 orders of magnitude. This gives confidence to our calculations of the quantities of Pu released on and off the Rocky Flats plant site. (auth)
Method of Analytic Evolution of Flat Distribution Amplitudes in QCD
Tandogan, Asli
2011-01-01
A new analytical method of performing ERBL evolution is described. The main goal is to develop an approach that works for distribution amplitudes that do not vanish at the end points, for which the standard method of expansion in Gegenbauer polynomials is inefficient. Two cases of the initial DA are considered: a purely flat DA, given by the same constant for all x, and an antisymmetric DA given by opposite constants for x 1/2. For a purely flat DA, the evolution is governed by an overall (x (1-x))^t dependence on the evolution parameter t times a factor that was calculated as an expansion in t. For an antisymmetric flat DA, an extra overall factor |1-2x|^{2t} appears due to a jump at x=1/2. A good convergence was observed in the t < 1/2 region. For larger t, one can use the standard method of the Gegenbauer expansion.
ACS/SBC Internal Lamp P-flat Monitoring
Avila, Roberto J.; Chiaberge, Marco; Bohlin, Ralph
2016-06-01
We report on a Cycle 23 calibration program to monitor the status of the SBC P-flat. We find random pixel to pixel changes to be small, with only ˜2% of pixels having changed by more than 3σ. There are coherent changes that we measure to be above the poisson errors, in some regions as high as 4% peak to peak. We therefore recommend that the ACS team obtain new observations in order to create a new P-flat. We also measured the degradation of the deuterium lamp used to create internal flats. The brightness of the lamp is currently ˜65% of its initial level, the degradation being dependent on lifetime usage.
Laminar film boiling on inclined isothermal flat plates.
Nagendra, H. R.
1973-01-01
Laminar film boiling from an inclined flat plate has been investigated analytically. Using the singular perturbation scheme, the complete set of Navier-Stokes equations is solved. The zeroth-order perturbation coinciding with the boundary-layer equations for vertical flat plates governs the problem. The higher-order perturbations become important near the leading edge and for large values of the inclination angle from the vertical. The assumption of zero interfacial velocity shows that, except for fluids having large (rho x mu) ratios, the results can be predicted using the vertical flat plate results by defining a modified Grashof parameter containing a cos phi term. When the interfacial shear is considered, the solutions indicate that for fluids having large (rho x mu) ratios, the heat transfer rates will be larger (approximately 15% maximum) than those predicted by the simplified model using zero interfacial velocity. In general, the inclination decreases the rate of heat transfer as well as the rate of evaporation.
Higher-spin flat space cosmologies with soft hair
Ammon, Martin; Grumiller, Daniel; Prohazka, Stefan; Riegler, Max; Wutte, Raphaela
2017-05-01
We present and discuss near horizon boundary conditions for flat space higher-spin gravity in three dimensions. As in related work our boundary conditions ensure regularity of the solutions independently of the charges. The asymptotic symmetry algebra is given by a set of \\widehat{u}(1) current algebras. The associated charges generate higher-spin soft hair. We derive the entropy for solutions that are continuously connected to flat space cosmologies and find the same result as in the spin-2 case: the entropy is linear in the spin-2 zero-mode charges and independent from the spin-3 charges. Using twisted Sugawara-like constructions of higher-spin currents we show that our simple result for entropy of higherspin flat space cosmologies coincides precisely with the complicated earlier results expressed in terms of higher-spin zero mode charges.
Electroluminescent Polymers and Carbon Nanotubes for Flat Panel Displays
Liming Dai; Limin Dong; Mei Gao; Shaoming Huang; Oddvar Johansen; Albert W.H.Mau,Zoran Vasic; Berthold Winkler; Yongyuang Yang
2000-01-01
polymeric light-emitting diodes(LEDs) with sufficient brightness. efficiencies, low driving voltages, and various interesting features have been reported. The relatively short device lifetime, however, still remains as a major problem to be solved before any commercial applications will be realized. In this regard,carbon nanotubes have recently been proposed as more robust electron field emitters for flat panel displays. We have synthesised large arrays of vertically aligned carbon nanotubes, from which micropatterns of the aligned nanotubes suitable for flat panel displays were fabricated on various substrates. In this paper, we summarise our work on the synthesis and microfabrication of electroluminescent polymers and carbon nanotubes for flat panel displays with reference to other complementary work as appropriate.
Micrometer-sized water droplet impingement dynamics and evaporation on a flat dry surface.
Briones, Alejandro M; Ervin, Jamie S; Putnam, Shawn A; Byrd, Larry W; Gschwender, Lois
2010-08-17
A comprehensive numerical and experimental investigation on micrometer-sized water droplet impact dynamics and evaporation on an unheated, flat, dry surface is conducted from the standpoint of spray-cooling technology. The axisymmetric time-dependent governing equations of continuity, momentum, energy, and species are solved. Surface tension, wall adhesion effect, gravitational body force, contact line dynamics, and evaporation are accounted for in the governing equations. The explicit volume of fluid (VOF) model with dynamic meshing and variable-time stepping in serial and parallel processors is used to capture the time-dependent liquid-gas interface motion throughout the computational domain. The numerical model includes temperature- and species-dependent thermodynamic and transport properties. The contact line dynamics and the evaporation rate are predicted using Blake's and Schrage's molecular kinetic models, respectively. An extensive grid independence study was conducted. Droplet impingement and evaporation data are acquired with a standard dispensing/imaging system and high-speed photography. The numerical results are compared with measurements reported in the literature for millimeter-size droplets and with current microdroplet experiments in terms of instantaneous droplet shape and temporal spread (R/D(0) or R/R(E)), flatness ratio (H/D(0)), and height (H/H(E)) profiles, as well as temporal volume (inverted A) profile. The Weber numbers (We) for impinging droplets vary from 1.4 to 35.2 at nearly constant Ohnesorge number (Oh) of approximately 0.025-0.029. Both numerical and experimental results show that there is air bubble entrapment due to impingement. Numerical results indicate that Blake's formulation provides better results than the static (SCA) and dynamic contact angle (DCA) approach in terms of temporal evolution of R/D(0) and H/D(0) (especially at the initial stages of spreading) and equilibrium flatness ratio (H(E)/D(0)). Blake's contact line
Zakharov V.I.
2015-01-01
Full Text Available We review briefly properties of chiral liquids, or liquids with massless fermionic constituents. We concentrate on three effects, namely, the low ratio of viscosity η to entropy density s, chiral magnetic and vortical effects. We sketch standard derivations of these effects in the hydrodynamic approximation and then concentrate on possibile unifying approach which is based on consideration of the (anomalously conserved axial current. The point is that the conservation of chirality is specific for the microscopic, field-theoretic description of massless fermions and their interactions. On the macroscopic side, the standard hydrodynamic equations are not consistent, generally speaking, with conservation of a helical macroscopic motion. Imposing extra constraints on the hydrodynamics might resolve this “clash-of-symmetries” paradox.
Atkins, K R
1959-01-01
Originally published in 1959 as part of the Cambridge Monographs on Physics series, this book addresses liquid helium from the dual perspectives of statistical mechanics and hydrodynamics. Atkins looks at both Helium Three and Helium Four, as well as the properties of a combination of the two isotopes. This book will be of value to anyone with an interest in the history of science and the study of one of the universe's most fundamental elements.
Static shape control of a flat shell structure
无
2006-01-01
The eight-node and forty-DOF piezoelectric shell element were applied to shape control of a flat shell structure. By the direct and converse effects, a distributed piezoelectric sensor layer was used to monitor the shape deformation and a distributed actuator layer was used to suppresse the deflection. A finite element model was for static response of laminated shell with piezoelectric sensors/actuators was derived. The model was verified by calculating piezoelectric polymeric PVDF bimorph beam. The results are in good agreement with those obtained by theoretical analysis of Tzou[1] and Hwang[2]. A case study of the static shape control of a flat shell structure is presented.
MD2013: Tune shift along the batch at flat top
Carver, Lee Robert; Buffat, Xavier; Giovannozzi, Massimo; Iadarola, Giovanni; Metral, Elias; Salvant, Benoit; CERN. Geneva. ATS Department
2017-01-01
A series of tests were performed that led to a measurement of the tune shift along a 96 bunch batch with 25ns spacing at flat top. The measurements demonstrated the ability of the transverse damper (ADT) to excite single bunches with minimal pulse leakage to neighbouring bunches (with 25ns bunch spacing). The processes were tested and refined with tests at injection and end of fill (EOF) before carrying out the excitation at flat top before a physics fill. The tune shift along the batch was shown to be less than ≈4x10-4 for both beams, both planes.
Chern-Simons functional under gauge transformations on flat bundles
Byun, Yanghyun; Kim, Joohee
2017-01-01
We describe the effect of a gauge transformation on the Chern-Simons functional in a thorough and unifying manner. We use the assumptions that the structure group is compact and connected and, in particular, that the principal bundle is flat. The Chern-Simons functional we consider is the one defined by choosing a flat reference connection. The most critical step in arriving at the main result is to show both the existence and the uniqueness of a cohomology class on the adjoint bundle such that it is the class of the so-called Maurer-Cartan 3-form when restricted to each fiber.
"Flat-Fish" vacuum chamber for the ISR
1983-01-01
The "Flat-Fish" vacuum chamber was a very special one for the ISR beam intersection I-4, inside the Split-Field Magnet. Technical descriptions are given with pictures 7802042 and 7712182. There were several generations of this chamber. This picture was taken during the last year of ISR operation. See also 7510230X, 7511123X, 7802039, 7802041. A flat-fish type vacuum chamber was also used at I-8, inside the Open Axial Field Magnet (OAFM, experiment 807 on large transverse momentum collision products), see 7901358.
Shear flow past a flat plate in hydromagnetics
S. R. N. Sastry
1980-01-01
Full Text Available The problem of simple shear flow past a flat plate has been extended to the hydromagnetic case in which a viscous, electrically conducting, incompressible fluid flows past an electrically insulated flat plate with a magnetic field parallel to the plate. For simplicity all physical parameters are assumed constant. A series solution for the velocity field has been developed for small values of a magnetic parameter. The equations governing this flow field were integrated numerically It is found that the effect of the magnetic field is to diminish and increase respectively, the first and second order contributions for the skin friction.
Damage Function Rating Procedure for Flat Slab Basement Shelters.
1982-12-01
with solid heads at the columns . These types of slabs are 33 I r~ Omm- D6U0St - m . -I ig. "-.TyiaaFalSasontucin 34 -4 called ribbed, or " waffle ", slabs ...and for design purposes are considered flat slabs with the solid heads at the columns performing the same function as the drop panels. Waffle flat...she:.ers, an upgrading method must be developed and verified by test for these critical stress areas adjacent to the column supports. Waffle Slabs
Vacuum energy in asymptotically flat 2+1 gravity
Miskovic, Olivera; Roy, Debraj
2016-01-01
We compute the vacuum energy of three-dimensional asymptotically flat space based on a Chern-Simons formulation for the Poincare group. The equivalent action is nothing but the Einstein-Hilbert term in the bulk plus half of the Gibbons-Hawking term at the boundary. The derivation is based on the evaluation of the Noether charges in the vacuum. We obtain that the vacuum energy of this space has the same value as the one of the asymptotically flat limit of three-dimensional anti-de Sitter space.
Classification of flat slant surfaces in complex Euclidean plane
Chen, Bang-Yen
2002-01-01
It is well-known that the classification of flat surfaces in Euclidean 3space is one of the most basic results in differential geometry. For surfaces in the complex Euclidean plane $C^{2}$ endowed with almost complex structure $J$ , flat surfaces are the simplest ones from intrinsic point of views. On the other hand, from $J$ -action point of views, the most natural surfaces in $C^{2}$ are slant surfaces, i.e., surfaces with constant Wintinger angle. In this paper the author completely classi...
Flat rotation curves using scalar-tensor theories
Cervantes-Cota, Jorge L [Depto de Fisica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 D.F. (Mexico); RodrIguez-Meza, M A [Depto de Fisica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 D.F. (Mexico); Nunez, Dario [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, A.P. 70-543, 04510 D.F. (Mexico)
2007-11-15
We computed flat rotation curves from scalar-tensor theories in their weak field limit. Our model, by construction, fits a flat rotation profile for velocities of stars. As a result, the form of the scalar field potential and DM distribution in a galaxy are determined. By taking into account the constraints for the fundamental parameters of the theory ({lambda}, {alpha}), it is possible to obtain analytical results for the density profiles. For positive and negative values of {alpha}, the DM matter profile is as cuspy as NFW's.
Benchmarking and Performance Improvement at Rocky Flats Environmental Technology Site
Elliott, C. [Kaiser-Hill Co., LLC, Golden, CO (United States)], Doyle, D. [USDOE Rocky Flats Office, Golden, CO (United States)], Featherman, W.D. [Project Performance Corp., Sterline, VA (United States)
1997-12-31
The Rocky Flats Environmental Technology Site (RFETS) has initiated a major work process improvement campaign using the tools of formalized benchmarking and streamlining. This paper provides insights into some of the process improvement activities performed at Rocky Flats from November 1995 through December 1996. It reviews the background, motivation, methodology, results, and lessons learned from this ongoing effort. The paper also presents important gains realized through process analysis and improvement including significant cost savings, productivity improvements, and an enhanced understanding of site work processes.
Vacuum energy in asymptotically flat 2 + 1 gravity
Miskovic, Olivera; Olea, Rodrigo; Roy, Debraj
2017-04-01
We compute the vacuum energy of three-dimensional asymptotically flat space based on a Chern-Simons formulation for the Poincaré group. The equivalent action is nothing but the Einstein-Hilbert term in the bulk plus half of the Gibbons-Hawking term at the boundary. The derivation is based on the evaluation of the Noether charges in the vacuum. We obtain that the vacuum energy of this space has the same value as the one of the asymptotically flat limit of three-dimensional anti-de Sitter space.
Technical advances of interventional fluoroscopy and flat panel image receptor.
Lin, Pei-Jan Paul
2008-11-01
In the past decade, various radiation reducing devices and control circuits have been implemented on fluoroscopic imaging equipment. Because of the potential for lengthy fluoroscopic procedures in interventional cardiovascular angiography, these devices and control circuits have been developed for the cardiac catheterization laboratories and interventional angiography suites. Additionally, fluoroscopic systems equipped with image intensifiers have benefited from technological advances in x-ray tube, x-ray generator, and spectral shaping filter technologies. The high heat capacity x-ray tube, the medium frequency inverter generator with high performance switching capability, and the patient dose reduction spectral shaping filter had already been implemented on the image intensified fluoroscopy systems. These three underlying technologies together with the automatic dose rate and image quality (ADRIQ) control logic allow patients undergoing cardiovascular angiography procedures to benefit from "lower patient dose" with "high image quality." While photoconductor (or phosphor plate) x-ray detectors and signal capture thin film transistor (TFT) and charge coupled device (CCD) arrays are analog in nature, the advent of the flat panel image receptor allowed for fluoroscopy procedures to become more streamlined. With the analog-to-digital converter built into the data lines, the flat panel image receptor appears to become a digital device. While the transition from image intensified fluoroscopy systems to flat panel image receptor fluoroscopy systems is part of the on-going "digitization of imaging," the value of a flat panel image receptor may have to be evaluated with respect to patient dose, image quality, and clinical application capabilities. The advantage of flat panel image receptors has yet to be fully explored. For instance, the flat panel image receptor has its disadvantages as compared to the image intensifiers; the cost of the equipment is probably the most
Feedforward Tracking Control of Flat Recurrent Fuzzy Systems
Gering, Stefan; Adamy, Jürgen
2014-12-01
Flatness based feedforward control has proven to be a feasible solution for the problem of tracking control, which may be applied to a broad class of nonlinear systems. If a flat output of the system is known, the control is often based on a feedforward controller generating a nominal input in combination with a linear controller stabilizing the linearized error dynamics around the trajectory. We show in this paper that the very same idea may be incorporated for tracking control of MIMO recurrent fuzzy systems. Their dynamics is given by means of linguistic differential equations but may be converted into a hybrid system representation, which then serves as the basis for controller synthesis.
Crossing of manifolds leads to flat dispersion: Blazed Littrow waveguides
Benisty, H.; Khayam, O. [Laboratoire Charles Fabry, Institut d' Optique, Universite Paris-Sud, CNRS, FR-91127 Palaiseau (France); Piskunov, N. [Laboratoire Charles Fabry, Institut d' Optique, Universite Paris-Sud, CNRS, FR-91127 Palaiseau (France); Faculty of Physics, M. V. Lomonosov Moscow State University, Moscow, 119991 (Russian Federation); Kashkarov, P. K. [Faculty of Physics, M. V. Lomonosov Moscow State University, Moscow, 119991 (Russian Federation)
2011-12-15
We display a photonic embodiment of the Demkov-Ostrovsky solution to the crossing of two manifolds made of equidistant modes thanks to broad periodic waveguides. We find clearly narrowing resonances that signal the singular, flat dispersion case that we had termed ''critical coupling.'' The reconciliation of band-edge confinement and cavity confinement, two pillars of photonics, appear from the guide length dependence of spectra. We suggest the generality of the Demkov-Ostrovsky or critical coupling flat dispersion across all kinds of waves, e.g., electronic and acoustic.
Flat Zipper-Unfolding Pairs for Platonic Solids
O'Rourke, Joseph
2010-01-01
We show that four of the five Platonic solids' surfaces may be cut open with a Hamiltonian path along edges and unfolded to a polygonal net each of which can "zipper-refold" to a flat doubly covered parallelogram, forming a rather compact representation of the surface. Thus these regular polyhedra have particular flat "zipper pairs." No such zipper pair exists for a dodecahedron, whose Hamiltonian unfoldings are "zip-rigid." This report is primarily an inventory of the possibilities, and raises more questions than it answers.
Strategic flat rolling of Ag/BSCCO-2223 tapes
Nielsen, Morten Storgård; Bech, Jakob Ilsted; Eriksen, Morten
2002-01-01
In the process of single-step flat rolling of multifilament Ag/BSCCO-2223 wire to tape previous work has shown the optimum strategy giving maximum critical current density to be it balance between the length and width strain, so they are of equal size i.e. so, that the logarithmic strain ratio, LSR......, reaches zero. In order to investigate the possible improvements by using multistep flat rolling, a new strategy to control the LSR in each individual step. i.e. to control the differential logarithmic strain ratio DLSR, has been investigated. The present paper shows that appropriate choice...... rights reserved....
Elliott, D. G.
1986-01-01
Boiling liquids pumped by device based on proven components. Expanding saturated liquid in nozzle and diverting its phases along separate paths in liquid/vapor separator raises pressure of liquid. Liquid cooled in process. Pump makes it unnecessary to pressurize cryogenic liquids in order to pump them. Problems of introducing noncondensable pressurizing gas avoided.
How realistic are flat-ramp-flat fault kinematic models? Comparing mechanical and kinematic models
Cruz, L.; Nevitt, J. M.; Hilley, G. E.; Seixas, G.
2015-12-01
Rock within the upper crust appears to deform according to elasto-plastic constitutive rules, but structural geologists often employ kinematic descriptions that prescribe particle motions irrespective of these physical properties. In this contribution, we examine the range of constitutive properties that are approximately implied by kinematic models by comparing predicted deformations between mechanical and kinematic models for identical fault geometric configurations. Specifically, we use the ABAQUS finite-element package to model a fault-bend-fold geometry using an elasto-plastic constitutive rule (the elastic component is linear and the plastic failure occurs according to a Mohr-Coulomb failure criterion). We varied physical properties in the mechanical model (i.e., Young's modulus, Poisson ratio, cohesion yield strength, internal friction angle, sliding friction angle) to determine the impact of each on the observed deformations, which were then compared to predictions of kinematic models parameterized with identical geometries. We found that a limited sub-set of physical properties were required to produce deformations that were similar to those predicted by the kinematic models. Specifically, mechanical models with low cohesion are required to allow the kink at the bottom of the flat-ramp geometry to remain stationary over time. Additionally, deformations produced by steep ramp geometries (30 degrees) are difficult to reconcile between the two types of models, while lower slope gradients better conform to the geometric assumptions. These physical properties may fall within the range of those observed in laboratory experiments, suggesting that particle motions predicted by kinematic models may provide an approximate representation of those produced by a physically consistent model under some circumstances.
Flat-Top and Stacking-Fault-Free GaAs-Related Nanopillars Grown on Si Substrates
Kouta Tateno
2012-01-01
Full Text Available The VLS (vapor-liquid-solid method is one of the promising techniques for growing vertical III-V compound semiconductor nanowires on Si for application to optoelectronic circuits. Heterostructures grown in the axial direction by the VLS method and in the radial direction by the general layer-by-layer growth method make it possible to fabricate complicated and functional three-dimensional structures in a bottom-up manner. We can grow some vertical heterostructure nanopillars with flat tops on Si(111 substrates, and we have obtained core-multishell Ga(InP/GaAs/GaP nanowires with flat tops and their air-gap structures by using selective wet etching. Simulations indicate that a high- factor of over 2000 can be achieved for this air-gap structure. From the GaAs growth experiments, we found that zincblende GaAs without any stacking faults can be grown after the GaP nanowire growth. Pillars containing a quantum dot and without stacking faults can be grown by using this method. We can also obtain flat-top pillars without removing the Au catalysts when using small Au particles.
McGlochlin, S.C.; Harder, R.V.; Jensen, R.T.; Pettis, S.A.; Roggenthen, D.K.
1990-09-18
Several technologies for destroying or decontaminating hazardous wastes were evaluated (during early 1988) as potential processes for treating low-level mixed wastes destined for destruction in the Fluidized Bed Incinerator. The processes that showed promise were retained for further consideration and placed into one (or more) of three categories based on projected availability: short, intermediate, and long-term. Three potential short-term options were identified for managing low-level mixed wastes generated or stored at the Rocky Flats Plant (operated by Rockwell International in 1988). These options are: (1) Continue storing at Rocky Flats, (2) Ship to Nevada Test Site for landfill disposal, or (3) Ship to the Idaho National Engineering Laboratory for incineration in the Waste Experimental Reduction Facility. The third option is preferable because the wastes will be destroyed. Idaho National Engineering Laboratory has received interim status for processing solid and liquid low-level mixed wastes. However, low-level mixed wastes will continue to be stored at Rocky Flats until the Department of Energy approval is received to ship to the Nevada Test Site or Idaho National Engineering Laboratory. Potential intermediate and long-term processes were identified; however, these processes should be combined into complete waste treatment systems'' that may serve as alternatives to the Fluidized Bed Incinerator. Waste treatment systems will be the subject of later work. 59 refs., 2 figs.
The Earth is Flat, and I Can Prove It!
Klinger, Art
1998-01-01
Describes an educational program that asks students to attempt to prove that the earth is spherical and that it rotates. Presents tips to pique student interest and charts related to sensing the spin, nonrotation notions, flat earth fallacies, evidence that the earth is spherical and rotates, and the role of watersheds in proving that the earth…
Broad spectral range synchronized flat-top arrayed waveguide grating
Akca, B. Imran; Doerr, Christopher R.; Pollnau, Markus; Ridder, de René M.
2012-01-01
A broad-band Mach-Zehnder-interferometer-synchronized flat-top arrayed waveguide grating is presented with a 0.5-dB bandwidth of 12 nm over 90 nm of spectral range and a central excess loss value of -0.5 dB.
Target aligned heliostat field layout for non-flat terrrain
Buck, R
2012-05-01
Full Text Available The layout for a solar tower test facility for CSIR, Pretoria, is described. The solar tower system is designed for 400kWth receiver outlet power. The heliostat field layout takes into account both the real (non-flat) topography of the terrain...
Higher-Spin Algebras, Holography and Flat Space
Sleight, Charlotte
2016-01-01
In this article we study the algebra generated by the holographically reconstructed cubic couplings for the type A minimal bosonic higher-spin theory on AdS$_{d+1}$, which were recently extracted from the free scalar $O(N)$ model. We demonstrate that it is equal to the unique higher-spin algebra for bosonic totally symmetric higher-spin fields in generic dimensions. This provides an explicit check of the holographic reconstruction and of the duality between higher-spin theories and the free $O(N)$ model in general dimensions, extending the result of Giombi and Yin in AdS$_4$. For completeness, we also address the same problem in the flat space for the cubic couplings derived by Metsaev in 1991, which are recovered in the flat limit of the AdS type-A cubic couplings. We observe that both flat and AdS$_4$ higher-spin Lorentz subalgebras coincide, hinting towards the existence of a full higher-spin symmetry behind the flat-space cubic couplings of Metsaev.
Dynamics of a rotating flat ellipsoid with a stochastic oblateness
Behar, Etienne; Pierret, Frédéric
2014-01-01
We derive a model for the motion of a rotating flat ellispoid with a stochastic flattening based on an invariance theorem for stochastic differential equations. A numerical study of a toy-model is performed leading to an intriguing coincidence with observational data.
Wind loads on solar energy systems, mounted on flat roofs
Geurts, C.P.W.; Bentum, C.A. van; Blackmore, P.
2005-01-01
Wind loads on solar energy systems are not covered by current wind loading standards. This paper describes results of a parametric study into the wind loads on solar energy systems, which are placed on flat roofs. Wind tunnel measurements have been carried out on a number of configurations. The resu
Causality violation in asymptotically flat space-times
Tipler, F.J.
1976-10-04
It is shown that a region containing closed timelike lines cannot evolve from regular initial data in a singularity-free asymptotically flat space-time. Furthermore, the causality assumption made in the black-hole uniqueness proofs is justified: It is demonstrated that no physically realistc nonsingular black hole can have a causality-violating exterior. (AIP)
Mutations of Laurent Polynomials and Flat Families with Toric Fibers
Ilten, Nathan Owen
2012-01-01
We give a general criterion for two toric varieties to appear as fibers in a flat family over the projective line. We apply this to show that certain birational transformations mapping a Laurent polynomial to another Laurent polynomial correspond to deformations between the associated toric varieties.
Ground-water conditions in Whisky Flat, Mineral County, Nevada
Eakin, T.E.; Robinson, T.W.
1950-01-01
As a part of the State-wide cooperative program between the Office of the State Engineer of Nevada and the U.S. Geological Survey, the Ground Water Branch of the Geological Survey made a reconnaissance study of ground-water conditions in Whisky Flat, Mineral County, Nevada.
A Jamesonian Analysis of "Flat World" Imagery in Education Discourse
Collin, Ross
2016-01-01
This article presents a discourse analysis of Kylene Beers' presidential address to the 2009 conference of the National Council of Teachers of English (NCTE-USA). The address, titled "Sailing over the Edge: Navigating the Uncharted Waters of a World Gone Flat," calls teachers to reject the standardized education of the industrial order…
Hyperconnected Attribute Filters Based on k-Flat Zones
Ouzounis, Georgios K.; Wilkinson, Michael H.F.
2011-01-01
In this paper, we present a new method for attribute filtering, combining contrast and structural information. Using hyperconnectivity based on k-flat zones, we improve the ability of attribute filters to retain internal details in detected objects. Simultaneously, we improve the suppression of smal
Certification and verification for calmac flat plate solar collector
1978-01-27
This document contains information used in the certification and verification of the Calmac Flat Plate Collector. Contained are such items as test procedures and results, information on materials used, Installation, Operation, and Maintenance Manuals, and other information pertaining to the verification and certification.
Tribology of flat contacts and its application in deep drawing
Emmens, W.C.
1997-01-01
The difference between steel and aluminium in sheet metal forming operations, and the influence of roughness in these operations, have been studied by making deep draw and friction experiments. The friction tests have been carried out with flat contacts to simulate the conditions in the blankholder.
Engineering flat electronic bands in quasiperiodic and fractal loop geometries
Nandy, Atanu, E-mail: atanunandy1989@gmail.com; Chakrabarti, Arunava, E-mail: arunava_chakrabarti@yahoo.co.in
2015-11-06
Exact construction of one electron eigenstates with flat, non-dispersive bands, and localized over clusters of various sizes is reported for a class of quasi-one-dimensional looped networks. Quasiperiodic Fibonacci and Berker fractal geometries are embedded in the arms of the loop threaded by a uniform magnetic flux. We work out an analytical scheme to unravel the localized single particle states pinned at various atomic sites or over clusters of them. The magnetic field is varied to control, in a subtle way, the extent of localization and the location of the flat band states in energy space. In addition to this we show that an appropriate tuning of the field can lead to a re-entrant behavior of the effective mass of the electron in a band, with a periodic flip in its sign. - Highlights: • Exact construction of eigenstates with flat and dispersive bands is reported. • Competition between translational order and growth of aperiodicity is discussed. • The effect of magnetic field on the location of flat band states is shown. • Flux tunable re-entrant behavior of the effective mass of electron is studied.
Simulation Study on Flat-Bottom Structure Slamming
CHEN Zhen; XIAO Xi; WANG De-yu
2005-01-01
A study is performed about the water entry of a flat-bottom structure by use of the FE software MSC Dytran. The aim of the study is to find out the effect of the air cushion and structural mass on the impact peak pressure and the role of splash in the course of water entry. Some FE models are built up and some cases including the flat-bottom structure with different masses impacting water at some constant or initial velocities are calculated. The calculation shows that air plays an important role in the course of water entry of a flat-bottom structure and the compression of the air captured by the flat-bottom structure produces the first peak pressure. And the mass of the structure has a great effect on the peak value of impact pressure. The structure with different masses will produce different impact pressures even at the same impact velocity. Splash will occur a long time after the impact pressure reaches the peak value. A formula is given for the calculation of the peak value of impact pressure in this paper.
Relaxing the parity conditions of asymptotically flat gravity
Compère, G.; Dehouck, F.
2011-01-01
Four-dimensional asymptotically flat spacetimes at spatial infinity are defined from first principles without imposing parity conditions or restrictions on the Weyl tensor. The Einstein-Hilbert action is shown to be a correct variational principle when it is supplemented by an anomalous counterterm
Interdistance Effects on Flat and Buckled Silicene Like-bilayers
Naji, S.; Khalil, B.; Labrim, H.; Bhihi, M.; Belhaj, A.; Benyoussef, A.; Lakhal, M.; El Kenz, A.
2014-03-01
Using ab intio numerical calculations based on the all-electron full-potential local-orbital minimum-basis scheme FPLO9.00-34, we discuss the interdistance effect on the energy gap of two parallel layers of the silicone systems. The like- bilayer systems we dealt with here are relying on a dynamic monolayer of silicene located at distance d along the normal direction z forming with a static one a (AA) stacking arrangement. In particular, we investigate the effect of the dynamic layer by varying the distance d starting from a distance around the bond length of Van der Waals. More precisely, we consider the flat and two buckled geometries in (AA) arrangements. The flat geometry is associated with the usual (AA) configuration appearing in the pure graphene material. For buckled geometry, we can distinguish two configurations. The first one corresponds to the usual buckled configuration that keeps the same vertical distance between the two layers atoms while the remaining one is obtained by reversing one silicene layer. We show that the band gap can be opened by simply varying the distance, starting around a Van der Waals distance, between two parallel silicene for flat and buckled geometries due to an electronic transition of electrons living in pz orbital states. Furthermore, we study the stability between the buckled and the flat configuration in the mono and bilayer system.
The Earth is Flat, and I Can Prove It!
Klinger, Art
1998-01-01
Describes an educational program that asks students to attempt to prove that the earth is spherical and that it rotates. Presents tips to pique student interest and charts related to sensing the spin, nonrotation notions, flat earth fallacies, evidence that the earth is spherical and rotates, and the role of watersheds in proving that the earth…
Skink predation by hedgehogs at Macraes Flat, Otago, New Zealand
Spitzen-van der Sluijs, A.; Spitzen, J.; Houston, D.; Stumpel, A.H.P.
2009-01-01
The stomach contents of 158 hedgehogs captured at Macraes Flat, Otago, New Zealand, over two summers in 2000 and 2001 were examined for the occurrence of lizards. The remains of at least 43 skinks (both Oligosoma nigriplantare polychroma and O. maccanni) and one gecko (Hoplodactylus sp.) were found.
Flat Lens Focusing Demonstrated With Left-Handed Metamaterial
Wilson, Jeffrey D.; Schwartz, Zachary D.; Chevalier, Christine T.; Downey, Alan N.; Vaden, Karl R.
2004-01-01
Left-handed metamaterials (LHM's) are a new media engineered to possess an effective negative index of refraction over a selected frequency range. This characteristic enables LHM's to exhibit physical properties never before observed. In particular, a negative index of refraction should cause electromagnetic radiation to refract or bend at a negative angle when entering an LHM, as shown in the figure above on the left. The figure on the right shows that this property could be used to bring radiation to a focus with a flat LHM lens. The advantage of a flat lens in comparison to a conventional curved lens is that the focal length could be varied simply by adjusting the distance between the lens and the electromagnetic wave source. In this in-house work, researchers at the NASA Glenn Research Center developed a computational model for LHM's with the three-dimensional electromagnetic commercial code Microwave Studio, constructed an LHM flat lens, and used it to experimentally demonstrate the reversed refraction and flat lens focusing of microwave radiation.
Polarization factor measurements of flat crystals using synchrotron radiation
Wohrer, K.; Touati, A.; Chetioui, A.; Rozet, J.P.; Chevallier, P.; Wang, J.X.; Bouisset, P.
1989-01-01
A method for measuring polarization factors of flat crystals, using a highly polarized beam source provided by synchrotron radiation, is presented. Application to the test of a graphite mosaic crystal, performed at the LURE-DCI facility in Orsay (France), is reported. Results concerning polarization factors at different energies are discussed in connection with measured crystal reflectivities.
Wind loads on solar energy systems, mounted on flat roofs
Geurts, C.P.W.; Bentum, C.A. van; Blackmore, P.
2005-01-01
Wind loads on solar energy systems are not covered by current wind loading standards. This paper describes results of a parametric study into the wind loads on solar energy systems, which are placed on flat roofs. Wind tunnel measurements have been carried out on a number of configurations. The resu
Evaluating rehabilitation efforts following the Milford Flat Fire—Data
U.S. Geological Survey, Department of the Interior — The focus of the study, associated with these data, is a 540-km2 area at the low-elevation northern end of the 1460-km2 Milford Flat Fire in west-central Utah, and...
19 CFR 148.102 - Flat rate of duty.
2010-04-01
... (CONTINUED) PERSONAL DECLARATIONS AND EXEMPTIONS Noncommercial Importations of Limited Value § 148.102 Flat... fair retail value in the country of acquisition. (b) American Samoa, Guam, the Northern Mariana Islands..., effective January 1, 2001, and 1.5 percent, effective January 1, 2002, of the fair retail value in...
The Anosov theorem for flat generalized Hantzsche-Wendt manifolds
Dekimpe, K.; De Rock, B.; Malfait, W.
2004-10-01
In this paper we prove that N( f)=| L( f)| for any continuous map f on a given orientable flat generalized Hantzsche-Wendt manifold. This is the analogue of a theorem of Anosov for continuous maps on nilmanifolds. We also show that the theorem always fails in the non-orientable case.
Modelonderzoek meetpunt Slenaken : "Flat - 5 triangular profile weir"
Bennink, J.; Pitlo, R.H.
1977-01-01
In de buurt van de Belgische grens werd in de Gulp te Slenaken (Zd. Limburg) door Rijkswaterstaat een meetstuw gebouwd van het type "Flat-V triangular profile weir". Een schaalmodel van de meetstuw is in Wageningen geijkt. De afvoergegevens zullen ook worden gebruikt door de "Studiegroep Gulp".
Integration using invariant operators Conformally flat radiation metrics
Edgar, S B
1999-01-01
A new method is presented for obtaining the general conformally flat radiation metric by using the differential operators of Machado Ramos and Vickers (a generalisation of the GHP operators) which are invariant under null rotations and spin and boosts. The solution is found by constructing involutive tables of these derivatives applied to the quantities which arise in the Karlhede classification of metrics.
The flat fishes of Porto Novo (India) (Pisces, Pleuronectiformes)
Ramanathan, N.; Natarajan, R.
1980-01-01
Thirty-two species of flat fishes from Porto Novo (India) are recorded and depicted. Along with meristic and morphometric data, lateral lines, scales, gillrakers, gillraker serrae, and pyloric caecae have been taken into consideration to provide information on the identity of each species. A key for
Invariants of tangles with flat connections in their complements
Kashaev, R
2010-01-01
Let G be a simple complex algebraic group. By using a notion of a G-category we define invariants of tangles with flat G-connections in their complements. We also show that quantized universal enveloping algebras at roots of unity provide examples of G-categories.
The structure of subsonic air wakes behind a flat plate
Barreras, F.; Dopazo, C. [Centro Politecnico Superior de Ingenieros Area de Mecanica de Fluidos, Zaragoza (Spain); Lozano, A.; Yates, A.J. [LITEC/CSIC, Maria de Luna 3 E-50015-Zaragoza (Spain)
1999-04-01
Acetone vapor planar laser-induced fluorescence has been used to visualize the structure of a subsonic air wake behind a flat plate. Longitudinal and transversal wavelengths have been directly measured from the acquired images. The ratio between them has been calculated to be 2/5. (orig.) With 3 figs., 1 tab., 10 refs.
Hyperconnected Attribute Filters Based on k-Flat Zones
Ouzounis, Georgios K.; Wilkinson, Michael H.F.
In this paper, we present a new method for attribute filtering, combining contrast and structural information. Using hyperconnectivity based on k-flat zones, we improve the ability of attribute filters to retain internal details in detected objects. Simultaneously, we improve the suppression of
A Broadband Metasurface-Based Terahertz Flat-Lens Array
Wang, Qiu
2015-02-12
A metasurface-based terahertz flat-lens array is proposed, comprising C-shaped split-ring resonators exhibiting locally engineerable phase discontinuities. Possessing a high numerical aperture, the planar lens array is flexible, robust, and shows excellent focusing characteristics in a broadband terahertz frequency. It could be an important step towards the development of planar terahertz focusing devices for practical applications.
New Sky Flats for HST's ACS/WFC
Lucas, Ray A.; Grogin, Norman A.
2016-06-01
We have begun experiments to make new sky flat files for HST's ACS/WFC. Sky flats can be especially useful for deep imaging in such as programs as deep, extragalactic survey programs because they can help to better deal with noise at low levels. Although we also hope to make similar sky flats for some other popular filters including F606W and F814W, we are beginning this experiment with the F435W filter on the ACS/WFC since it is a popular filter in use in many deep extragalactic surveys, and since the bluer filters such as F435W generally have lower throughput and images in that filter are typically noisier than others at some longer mid-optical wavelengths. Initially, although sources will be masked in these images, etc. we are endeavoring to use just post-SM4 F435W images of duration equal to or greater than 800 seconds and which are free of bright stars in order to try and avoid scattered light and sky background color issues as much as possible, although the sky in different images taken at different times and in different directions will likely have some different background levels and color terms in any event. However, our hope is that the final sky flats will be of sufficient S/N to be good calibrators for deep survey programs.
Rigidity of Minimal Submanifolds with Flat Normal Bundle
Hai-Ping Fu
2010-09-01
Let $M^n(n≥ 3)$ be an -dimensional complete immersed $\\frac{n-2}{n}$-superstable minimal submanifold in an $(n+p)$-dimensional Euclidean space $\\mathbb{R}^{n+p}$ with flat normal bundle. We prove that if the second fundamental form of satisfies some decay conditions, then is an affine plane or a catenoid in some Euclidean subspace.
Peter N Cox
1996-01-01
Full Text Available There has been a recent explosion of interest in the use of liquid ventilation. Over time humans have lost the physiological attributes necessary for respiration in water. However, perfluorocarbons have high solubilities for oxygen and carbon dioxide, as well as a low surface tension. These characteristics allow them to be used as a medium to assist gas exchange and recruit atelectatic-dependent lung zones in respiratory distress syndrome. Current trials may prove perfluorocarbon to be a useful adjunct in lung protective strategies in respiratory distress syndrome.
Is Flat fielding Safe for Precision CCD Astronomy?
Baumer, Michael; Davis, Christopher P.; Roodman, Aaron
2017-08-01
The ambitious goals of precision cosmology with wide-field optical surveys such as the Dark Energy Survey (DES) and the Large Synoptic Survey Telescope (LSST) demand precision CCD astronomy as their foundation. This in turn requires an understanding of previously uncharacterized sources of systematic error in CCD sensors, many of which manifest themselves as static effective variations in pixel area. Such variation renders a critical assumption behind the traditional procedure of flat fielding—that a sensor’s pixels comprise a uniform grid—invalid. In this work, we present a method to infer a curl-free model of a sensor’s underlying pixel grid from flat-field images, incorporating the superposition of all electrostatic sensor effects—both known and unknown—present in flat-field data. We use these pixel grid models to estimate the overall impact of sensor systematics on photometry, astrometry, and PSF shape measurements in a representative sensor from the Dark Energy Camera (DECam) and a prototype LSST sensor. Applying the method to DECam data recovers known significant sensor effects for which corrections are currently being developed within DES. For an LSST prototype CCD with pixel-response non-uniformity (PRNU) of 0.4%, we find the impact of “improper” flat fielding on these observables is negligible in nominal .7″ seeing conditions. These errors scale linearly with the PRNU, so for future LSST production sensors, which may have larger PRNU, our method provides a way to assess whether pixel-level calibration beyond flat fielding will be required.
Magnetotelluric Data, North Central Yucca Flat, Nevada Test Site, Nevada
J.M. Williams; B.D. Rodriguez, and T.H. Asch
2005-11-23
Nuclear weapons are integral to the defense of the United States. The U.S. Department of Energy, as the steward of these devices, must continue to gauge the efficacy of the individual weapons. This could be accomplished by occasional testing at the Nevada Test Site (NTS) in Nevada, northwest of Las Vegas. Yucca Flat Basin is one of the testing areas at the NTS. One issue of concern is the nature of the somewhat poorly constrained pre-Tertiary geology and its effects on ground-water flow in the area subsequent to a nuclear test. Ground-water modelers would like to know more about the hydrostratigraphy and geologic structure to support a hydrostratigraphic framework model that is under development for the Yucca Flat Corrective Action Unit (CAU). During 2003, the U.S. Geological Survey (USGS) collected and processed Magnetotelluric (MT) and Audio-magnetotelluric (AMT) data at the Nevada Test Site in and near Yucca Flat to help characterize this pre-Tertiary geology. That work will help to define the character, thickness, and lateral extent of pre-Tertiary confining units. In particular, a major goal has been to define the upper clastic confining unit (UCCU) in the Yucca Flat area. Interpretation will include a three-dimensional (3-D) character analysis and two-dimensional (2-D) resistivity model. The purpose of this report is to release the MT sounding data for north central Yucca Flat, Profile 7, as shown in Figure 1. No interpretation of the data is included here.
Magnetotelluric Data, Northern Yucca Flat, Nevada Test Site, Nevada
J.M. Williams; B.D. Rodriguez, and T.H. Asch
2005-11-23
Nuclear weapons are integral to the defense of the United States. The U.S. Department of Energy, as the steward of these devices, must continue to gauge the efficacy of the individual weapons. This could be accomplished by occasional testing at the Nevada Test Site (NTS) in Nevada, northwest of Las Vegas. Yucca Flat Basin is one of the testing areas at the NTS. One issue of concern is the nature of the somewhat poorly constrained pre-Tertiary geology and its effects on ground-water flow in the area subsequent to a nuclear test. Ground-water modelers would like to know more about the hydrostratigraphy and geologic structure to support a hydrostratigraphic framework model that is under development for the Yucca Flat Corrective Action Unit (CAU). During 2003, the U.S. Geological Survey (USGS) collected and processed Magnetotelluric (MT) and Audio-magnetotelluric (AMT) data at the Nevada Test Site in and near Yucca Flat to help characterize this pre-Tertiary geology. That work will help to define the character, thickness, and lateral extent of pre-Tertiary confining units. In particular, a major goal has been to define the upper clastic confining unit (UCCU) in the Yucca Flat area. Interpretation will include a three-dimensional (3-D) character analysis and two-dimensional (2-D) resistivity model. The purpose of this report is to release the MT sounding data for Profile 2, (fig. 1), located in the northern Yucca Flat area. No interpretation of the data is included here.
Demonstrating superconductivity at liquid nitrogen temperatures
Early, E. A.; Seaman, C. L.; Yang, K. N.; Maple, M. B.
1988-07-01
This article describes two demonstrations of superconductivity at the boiling temperature of liquid nitrogen (77 K) using the 90 K superconductor YBa2Cu3O7-δ(δ≊0.2). Both demonstrations involve the repulsion of a permanent magnet by a superconductor due to the expulsion of the magnetic field from the interior of the latter. In the first demonstration, the repulsion is manifested in the separation of a permanent magnet and a superconductor that are suspended from separate threads, while in the second it results in the levitation of a permanent magnet above a flat superconducting disk.
A numerical investigation of fine sediment transport at intertidal flat
Hsu, T.; Chen, S.; Ogston, A. S.
2010-12-01
A detailed numerical model is developed to study the hydrodynamic and fine sediment transport processes at tidal flats. The critical science issues to be investigated here are to quantify the main mechanisms causing landward and seaward transports. Prior modeling studies have identified the settling-lag effects as the main mechanism causing landward fine sediment transport. Field studies have also observed pronounced landward transport due to the movement of shallow-water’s turbid edge which is associated with bed erodibility and wetting-drying process. Recent 3D coastal numerical modeling of Skagit tidal flat (Chen et al. 2010, J. Geophys. Res., in press) is able to model settling-lag-induced landward transport. However, the observed short residence time for river-delivered sediment cannot be reproduced by the model, suggesting that a key offshore transport mechanism is not captured by the exiting coastal models. Field studies carried out in the ongoing Tidal Flat DRI have observed the so-called ebb tide sediment pulse, which seems to support the export of sediment through channels (Nowacki et al. 2010, this meeting) that balances landward fluxes. Both the bed erosion at water’s edge and ebb tide sediment pulse occur at a very shallow water depths. Conventional coastal models have difficulties in resolving the shallow flow at the wetting and drying seabed and some numerical approximations, such as specifying a minimum artificial flow depth, are often adopted. Therefore, a small-scale study is necessary before an appropriate parameterization for these transport mechanisms can be adopted by an estuarine/coastal model. In this study, a two-dimensional-vertical numerical model solving Reynolds-averaged Navier-Stokes equations with a Volume of Fluid (VOF) scheme to track the free surface evolution is adopted. The VOF scheme allows a more realistic simulation of the wetting and drying processes. For the simulation of tidal flow over a flat of constant slope (slope
From Funding Liquidity to Market Liquidity
Dick-Nielsen, Jens; Lund, Jesper; Gyntelberg, Jacob
This paper shows empirically that funding liquidity drives market liquidity. As it becomes harder to secure term funding in the money markets, liquidity deteriorates in the Danish bond market. We show that the first principal component of bond market liquidity is driven by the market makers' abil...... for other European government bonds using MTS data. The findings suggest that regulatory bond based liquidity buffers for banks will have limited effectiveness.......This paper shows empirically that funding liquidity drives market liquidity. As it becomes harder to secure term funding in the money markets, liquidity deteriorates in the Danish bond market. We show that the first principal component of bond market liquidity is driven by the market makers...
Fermion condensate generates a new state of matter by making flat bands
Shaginyan, V. R.; Popov, K. G.; Khodel, V. A.
2014-09-01
This short review paper is devoted to 90th anniversary of S.T. Belyaev birthday. Belyaev's ideas associated with the condensate state in Bose interacting systems have stimulated intensive studies of the possible manifestation of such a condensation in Fermi systems. In many Fermi systems and compounds at zero temperature a phase transition happens that leads to a quite specific state called fermion condensation. As a signal of such a fermion condensation quantum phase transition (FCQPT) serves unlimited increase of the effective mass of quasiparticles that determines the excitation spectrum and creates flat bands. We show that the class of Fermi liquids with the fermion condensate forms a new state of matter. We discuss the phase diagrams and the physical properties of systems located near that phase transition. A common and essential feature of such systems is quasiparticles different from those suggested by L.D. Landau by crucial dependence of their effective mass on temperature, external magnetic field, pressure, etc. It is demonstrated that a huge amount of experimental data collected on different compounds suggest that they, starting from some temperature and down, form the new state of matter, and are governed by the fermion condensation. Our discussion shows that the theory of fermion condensation develops completely good description of the NFL behavior of strongly correlated Fermi systems. Moreover, the fermion condensation can be considered as the universal reason for the NFL behavior observed in various HF metals, liquids, compounds with quantum spin liquids, and quasicrystals. We show that these systems exhibit universal scaling behavior of their thermodynamic properties. Therefore, the quantum critical physics of different strongly correlated compounds is universal, and emerges regardless of the underlying microscopic details of the compounds. This uniform behavior, governed by the universal quantum critical physics, allows us to view it as the main
Survey of Morphological Changes on Tidal Flats in Estuaries
Albers, Thorsten; von Lieberman, Nicole
2010-05-01
Tidal flat areas in estuaries are affected by strong morphodynamics. Changes of sedimentation and erosion occur on very different time and spatial scales. These changes challenge the responsible authorities due to the high importance of sufficient navigation channel depths and the ecological importance of those unique zones. The Hamburg University of Technology in cooperation with the Hamburg Port Authority runs broad field measurements on different tidal flat areas in the Elbe estuary. The results provide a fundamental data set, which improves the knowledge about morphodynamic processes and verifies mathematical descriptions. The field measurements focus on two investigation areas: One area is located in the mouth of the estuary and represents a marine tidal flat. The other one is located near the city of Hamburg and typifies a limnic tidal flat area. For more than 3 years water levels, waves, current parameters and suspended sediment concentrations are being recorded continuously and in a high resolution at different positions. Altogether, three measuring positions are operated at any time. To observe the consequences of the morphodynamic processes, the bathymetry of the investigation areas is determined with a multi-beam echo sounder (MBES) in frequent intervals. The main goal of the research project is to improve the knowledge about morphodynamic processes on tidal flats. Derived from the field data certain patterns of erosion, sediment transport and sedimentation could be observed depending on tidal currents, waves and large scale weather conditions. Seasonal effects are analysed as well as the influence of extreme events. A comparison of the processes observed on marine and limnic areas is done, whereas the latter additionally is affected by upstream water discharge. For example, on the marine tidal flats the sediment transport capacity was analysed: Extreme events cause a short peak, which does not result in significant bathymetric changes. Larger
Procházka, Michal
2011-01-01
This work deals with the liquidation of the company focusing on commercial companies. It describes whole process of liquidation from decision to liquidate to delete the company from the Commercial Register. The work also focuses on legal, accounting and tax site of liquidation. Accounting practices in the liquidation process are illustrated on the example of a fictive company.
2013-11-19
... International Trade Administration Diffusion-Annealed, Nickel-Plated Flat-Rolled Steel Products From Japan...-annealed, nickel-plated flat-rolled steel products (certain nickel-plated, flat-rolled steel) from Japan..., nickel-plated flat-rolled steel products included in this investigation are flat-rolled,...
Elastic Torque and the Levitation of Metal Wires by a Nematic Liquid Crystal
Lapointe, C.; Hultgren, A.; Silevitch, D. M.; Felton, E. J.; Reich, D. H.; Leheny, R. L.
2004-01-01
Anisotropic particles suspended in a nematic liquid crystal disturb the alignment of the liquid crystal molecules and experience small forces that depend on the particles' orientation. We have measured these forces using magnetic nanowires. The torque on a wire and its orientation-dependent repulsion from a flat surface are quantitatively consistent with theoretical predictions based on the elastic properties of the liquid crystal. These forces can also be used to manipulate submicrometer-scale particles. We show that controlled spatial variations in the liquid crystal's alignment convert the torque on a wire to a translational force that levitates the wire to a specified height.
Flat Chern band in a two-dimensional organometallic framework.
Liu, Zheng; Wang, Zheng-Fei; Mei, Jia-Wei; Wu, Yong-Shi; Liu, Feng
2013-03-01
By combining exotic band dispersion with nontrivial band topology, an interesting type of band structure, namely, the flat Chern band, has recently been proposed to spawn high-temperature fractional quantum Hall states. Despite the proposal of several theoretical lattice models, however, it remains doubtful whether such a "romance of flatland" could exist in a real material. Here, we present a first-principles design of a two-dimensional indium-phenylene organometallic framework that realizes a nearly flat Chern band right around the Fermi level by combining lattice geometry, spin-orbit coupling, and ferromagnetism. An effective four-band model is constructed to reproduce the first-principles results. Our design, in addition, provides a general strategy to synthesize topologically nontrivial materials by virtue of organic chemistry and nanotechnology.
A flat triangular shell element with Loof nodes
Poulsen, Peter Noe; Damkilde, Lars
1996-01-01
In the formulation of flat shell elements it is difficult to achieve inter-element compatibility between membrane and transverse displacements for non-coplanar elements. Many elements lack proper nodal degrees of freedom to model intersections making the assembly of elements troublesome. A flat...... triangular shell element is established by a combination of a new plate bending element DKTL and the well-known linear membrane strain element LST, and for this element the above-mentioned deficiences are avoided. The plate bending element DKTL is based on Discrete Kirchhoff Theory and Loof nodes. The nodal...... configuration of the element is similar to the SemiLoof element, and the formulation is an improvement of a previous formulation. The element is used for both linear statics, linear buckling and geometrical non-linear analysis, and numerical examples are presented to show the robustness, accuracy and quick...
Polymer solidification of mixed wastes at the Rocky Flats Plant
Faucette, A.M.; Logsdon, B.W.; Lucerna, J.J.; Yudnich, R.J.
1994-02-01
The Rocky Flats Plant is pursuing polymer solidification as a viable treatment option for several mixed waste streams that are subject to land disposal restrictions within the Resource Conservation and Recovery Act provisions. Tests completed to date using both surrogate and actual wastes indicate that polyethylene microencapsulation is a viable treatment option for several mixed wastes at the Rocky Flats Plant, including nitrate salts, sludges, and secondary wastes such as ash. Treatability studies conducted on actual salt waste demonstrated that the process is capable of producing waste forms that comply with all applicable regulatory criteria, including the Toxicity Characteristic Leaching Procedure. Tests have also been conducted to evaluate the feasibility of macroencapsulating certain debris wastes in polymers. Several methods and plastics have been tested for macroencapsulation, including post-consumer recycle and regrind polyethylene.
Asymptotically flat black holes with scalar hair: a review
Herdeiro, Carlos A R
2015-01-01
We consider the status of black hole solutions with non-trivial scalar fields but no gauge fields, in four dimensional asymptotically flat space-times, reviewing both classical results and recent developments. We start by providing a simple illustration on the physical difference between black holes in electro-vacuum and scalar-vacuum. Next, we review no-scalar-hair theorems. In particular, we detail an influential theorem by Bekenstein and stress three key assumptions: 1) the type of scalar field equation; 2) the spacetime symmetry inheritance by the scalar field; 3) an energy condition. Then, we list regular (on and outside the horizon), asymptotically flat BH solutions with scalar hair, organizing them by the assumption which is violated in each case and distinguishing primary from secondary hair. We provide a table summary of the state of the art.
Zoology of instanton solutions in flat potential barriers
Battarra, Lorenzo; Lehners, Jean-Luc
2013-01-01
We perform a detailed study of the existence and the properties of O(4)-invariant instanton solutions in Einstein-scalar theory in the presence of flat potential barriers, i.e. barriers where the second derivative of the potential is small at the top of the barrier. We find a whole zoo of solutions: Hawking-Moss, Coleman-De Luccia (CdL), oscillating instantons, asymmetric CdL as well as other non-standard CdL-like solutions with additional negative modes in their spectrum of fluctuations. Our work shows how these different branches of solutions are connected to each other via "critical" instantons possessing an extra zero mode fluctuation. Overall, the space of finite action euclidean solutions to these theories with flat barriers is surprisingly rich and intricate.
Flat acoustic lens by acoustic grating with curled slits
Peng, Pai
2014-10-01
We design a flat sub-wavelength lens that can focus acoustic wave. We analytically study the transmission through an acoustic grating with curled slits, which can serve as a material with tunable impedance and refractive index for acoustic waves. The effective parameters rely on the geometry of the slits and are independent of frequency. A flat acoustic focusing lens by such acoustic grating with gradient effective refractive index is designed. The focusing effect is clearly observed in simulations and well predicted by the theory. We demonstrate that despite the large impedance mismatch between the acoustic lens and the matrix, the intensity at the focal point is still high due to Fabry-Perot resonance.
Flat Rating Concept Introduced in the GTX Engine
Arun Prasad
1985-04-01
Full Text Available An attempt has been made to explain the flat rating concept introduced in the GTX engine being developed at GTRE. The contemporary high pressure ratio engines lose thrust rapidly with increase in compressor inlet total temperature (T1. This loss of thrust with increase in T1 becomes significant in the case of bypass engine, with thrust drop increasing with increase in bypass ratio. The concept of variable cycle achieved by varying the maximum cycle temperature in order to increase the available dry thrust is explained. In recent days this concept of variable cycle has been recognised in the design of engines for combat aircraft with particular reference to supersonic cruise at altitude. An attempt has also been made to explain the control law in order to achieve the flat rating.
Railway Wheel Flat Detection Based on Improved Empirical Mode Decomposition
Yifan Li
2016-01-01
Full Text Available This study explores the capacity of the improved empirical mode decomposition (EMD in railway wheel flat detection. Aiming at the mode mixing problem of EMD, an EMD energy conservation theory and an intrinsic mode function (IMF superposition theory are presented and derived, respectively. Based on the above two theories, an improved EMD method is further proposed. The advantage of the improved EMD is evaluated by a simulated vibration signal. Then this method is applied to study the axle box vibration response caused by wheel flats, considering the influence of both track irregularity and vehicle running speed on diagnosis results. Finally, the effectiveness of the proposed method is verified by a test rig experiment. Research results demonstrate that the improved EMD can inhibit mode mixing phenomenon and extract the wheel fault characteristic effectively.
Frequency selective surface with a flat topped passband
Hongyan Jia; Jinsong Gao; Xiaoguo Feng; Qingwen Meng
2007-01-01
Two frequency selective surface (FSS) configurations with flat topped passband are presented in this paper.One configuration is single layer FSS with λ/4 thickness dielectric loaded on both sides, and the other is double layers FSS. Based on the modal matching method, the frequency response properties including angle effect and polarization effect of both FSS configurations are analyzed, and the plots of the frequency versus transmission coefficient are obtained for different incident angles and polarizations. It is shown that the structure with the single layer FSS embedded centrally in the λ/2 thickness dielectric has a wider flat top bandwidth of 6.8 GHz than that of the double layers FSS of 3 GHz. In addition, the fabrication of single layer is relatively easier than the double layers FSS.
Extraction of Flat and Nested Data Records from Web Pages
Hiremath, P S
2010-01-01
This paper studies the problem of identification and extraction of flat and nested data records from a given web page. With the explosive growth of information sources available on the World Wide Web, it has become increasingly difficult to identify the relevant pieces of information, since web pages are often cluttered with irrelevant content like advertisements, navigation-panels, copyright notices etc., surrounding the main content of the web page. Hence, it is useful to mine such data regions and data records in order to extract information from such web pages to provide value-added services. Currently available automatic techniques to mine data regions and data records from web pages are still unsatisfactory because of their poor performance. In this paper a novel method to identify and extract the flat and nested data records from the web pages automatically is proposed. It comprises of two steps : (1) Identification and Extraction of the data regions based on visual clues information. (2) Identificatio...
Performance analysis and experimental study on Flat Optical Comb Generation
Haining Li
2013-01-01
Full Text Available The performance of the optical frequency comb generation based on the re-circulating frequency shifter has been analyzed and demonstrated in this paper. We have theoretically analyzed the condition for flatness of the optical frequency comb and the relative intensity noise influence. We find out the influence to the flatness of optical comb owing to amplifier relative intensity noise and modulator relative factors imperfect, such as input RF signals amplitude and phase deviation and modulator defect owing to manufacture for the first time. Moreover, to verify the theoretical analysis, a 16 comb lines and spacing 12.5 GHz RFS generation system have also been carried out, and the results are in good agreement with the theoretical analysis results.
Relaxing the parity conditions of asymptotically flat gravity
Compère, Geoffrey; Dehouck, François
2011-12-01
Four-dimensional asymptotically flat spacetimes at spatial infinity are defined from first principles without imposing parity conditions or restrictions on the Weyl tensor. The Einstein-Hilbert action is shown to be a correct variational principle when it is supplemented by an anomalous counterterm which breaks asymptotic translation, supertranslation and logarithmic translation invariance. Poincaré transformations as well as supertranslations and logarithmic translations are associated with finite and conserved charges which represent the asymptotic symmetry group. Lorentz charges as well as logarithmic translations transform anomalously under a change of regulator. Lorentz charges are generally nonlinear functionals of the asymptotic fields but reduce to well-known linear expressions when parity conditions hold. We also define a covariant phase space of asymptotically flat spacetimes with parity conditions but without restrictions on the Weyl tensor. In this phase space, the anomaly plays classically no dynamical role. Supertranslations are pure gauge and the asymptotic symmetry group is the expected Poincaré group.
Scalar hairy black holes and solitons in asymptotically flat spacetimes
Nucamendi, U; Nucamendi, Ulises; Salgado, Marcelo
2003-01-01
A numerical analysis shows that a class of scalar-tensor theories of gravity with a scalar field minimally and nonminimally coupled to the curvature allows static and spherically symmetric black hole solutions with scalar-field hair in asymptotically flat spacetimes. In the limit when the horizon radius of the black hole tends to zero, regular scalar solitons are found. The asymptotically flat solutions are obtained provided that the scalar potential $V(\\phi)$ of the theory is ``finetuned'' such that its local minimum is also a zero of the potential, the scalar field settling asymptotically at that minimum. The configurations, although unstable under spherically symmetric linear perturbations, are regular and thus can serve as counterexamples to the no-scalar-hair conjecture.
Actinide solution processing at the Rocky Flats Environmental Technology Site
NONE
1995-04-01
The Department of Energy (DOE) has prepared an Environmental Assessment (EA), DOE/EA-1039, for radioactive solution removal and processing at Rocky Flats Environmental Technology Site, Golden, Colorado. The proposal for solution removal and processing is in response to independent safety assessments and an agreement with the State of Colorado to remove mixed residues at Rocky Flats and reduce the risk of future accidents. Monthly public meetings were held during the scoping and preparation of the EA. The scope of the EA included evaluations of alternative methods and locations of solution processing. A comment period from February 20, 1995 through March 21, 1995 was provided to the public and the State of Colorado to offer written comment on the EA. Comments were received from the State of Colorado and the U.S. Environmental Protection Agency. A response to the agency comments is included in the Final EA.
A simple method to construct Flat Band lattices
Morales-Inostroza, Luis
2016-01-01
We develop a simple and general method to construct arbitrary Flat Band lattices. We identify the basic ingredients behind zero-dispersion bands and develop a method to construct extended lattices based on a consecutive repetition of a given mini-array. The number of degenerated localized states is defined by the number of connected mini-arrays times the number of modes preserving the symmetry at a given connector site. In this way, we create one or more (depending on the lattice geometry) complete degenerated Flat Bands for quasi-one and two-dimensional systems. We probe our method by studying several examples, and discuss the effect of additional interactions like anisotropy or nonlinearity. At the end, we test our method by studying numerically a ribbon lattice using a continuous description.
Acoustic insulation of recent flat buildings in Pamplona, Spain
Arana, Miguel A.; San Martin, Ricardo; Vela, Antonio; San Martin, Maria L.
2002-11-01
The Municipal Government of Pamplona and the Housing Department of the Government of Navarra (Spain) decided to evaluate acoustic insulation of new flat buildings in Pamplona. Such study was ordered to the Acoustic Laboratory of the Public University of Navarra. During the last year, measurements relating to acoustic insulation were carried out in most of the new blocks of flats made in Pamplona. The results obtained show that acoustic insulation is insufficient in most buildings both for airborne sound reduction and for impact sound. The figures required by Spanish legislation do not fulfil in more than 80 percent of the cases. On the other hand, a great correlation between sound reduction figures obtained from index of ISO 140-4 and from R (in dBA) of the Spanish norm for in situ measurements was carried out. A new Spanish legislation will be approved shortly.
Detailed Modeling of Flat Plate Solar Collector with Vacuum Glazing
Viacheslav Shemelin
2017-01-01
Full Text Available A theoretical analysis of flat plate solar collectors with a vacuum glazing is presented. Different configurations of the collector have been investigated by a detailed theoretical model based on a combined external and internal energy balance of the absorber. Performance characteristics for vacuum flat plate collector alternatives have been derived. Subsequently, annual energy gains have been evaluated for a selected variant and compared with state-of-the-art vacuum tube collectors. The results of modeling indicate that, in the case of using advanced vacuum glazing with optimized low-emissivity coating (emissivity 0.20, solar transmittance 0.85, it is possible to achieve efficiency parameters similar to or even better than vacuum tube collectors. The design presented in this paper can be considered promising for the extension of the applicability range of FPC and could be used in applications, which require low-to-medium temperature level.
A dynamic simulation of a flat-plate collector system
Annino, A.
1983-04-01
A numerical model for the performance of a flat plate solar collector array is presented, with account taken of thermal transients and calculation on a microcomputer. The system modeled consists of a flat plate array, the heat transfer fluid, an insulated storage tank, an exchange loop for heating a secondary fluid, and a load maintained by a pump. The one-dimensional analysis includes equations for the energy balances, with consideration given to heat losses to the outside. A function is defined for the total incident solar radiation, and behavior is simulated over the entire 24-hr day, weighted by the highest and lowest recorded temperatures. Good agreement has been found with experimental data.
Punching strength of reinforced concrete flat slabs without shear reinforcement
P. V. P. Sacramento
Full Text Available Punching strength is a critical point in the design of flat slabs and due to the lack of a theoretical method capable of explaining this phenomenon, empirical formulations presented by codes of practice are still the most used method to check the bearing capacity of slab-column connections. This paper discusses relevant aspects of the development of flat slabs, the factors that influence the punching resistance of slabs without shear reinforcement and makes comparisons between the experimental results organized in a database with 74 slabs carefully selected with theoretical results using the recommendations of ACI 318, EUROCODE 2 and NBR 6118 and also through the Critical Shear Crack Theory, presented by Muttoni (2008 and incorporated the new fib Model Code (2010.
Waterbird - Expanded Scoter and Scaup Survey: Boreal Alaska and Old Crow Flats, Canada products
US Fish and Wildlife Service, Department of the Interior — Products resulting from the Yukon Flats NWR project "Waterbird - Expanded Scoter and Scaup Survey: Boreal Alaska and Old Crow Flats, Canada" (PRIMR survey...
Flat lens imaging does not need negative refraction
Kuo, Chao-Hsien; Ye, Zhen
2003-01-01
In a recent communication, Parimi et al. (Nature 426, 404 (2003)) reported the experimental results on imaging by a flat lens made of photonic crystals. They attributed the observed focusing to the negative refraction expected for the Left-Handed-Materials (LHMs). Here we demonstrate that the experimental observation is irrelevant to the negative refraction of LHMs. Rather, the phenomenon is a natural result of the anisotropic scattering by an array of scatterers.
Flat Plate Reduction in a Water Tunnel Using Riblets
1987-05-01
II ~Ci +c SE- 2 8 0Lg E (D so (wwI) 10 DRAG CALCULATIONS The drag on the flat plate was calculated using D = bpU 20 The drag reduction over the...described in the previous section, are used so that bpU 2. is a constant, and that the drag upstream of the leading edge of the test surface is the same
Optimization design of flat-band long-period grating
Yumin Liu(刘玉敏); Zhongyuan Yu(俞重远); Jianzhong Zhang(张建忠); Bojun Yang(杨伯君); Xiaoguang Zhang(张晓光)
2004-01-01
We present a method to optimize the flat-band long-period fiber Bragg grating (FBG) in this letter. The method is based on the particle swarm optimization method and the matrix transmission method. The optimized refractive modulation profile does not introduce so many phase shifts and is easier to fabricate compared with that of layer-peeling method which introduces lots of π phase shift at each zero point of apodization profile in designing for the same problem.
A rigidity theorem for complete noncompact Bach-flat manifolds
Chu, Yawei
2011-02-01
Let (M4,g) be a four-dimensional complete noncompact Bach-flat Riemannian manifold with positive Yamabe constant. In this paper, we show that (M4,g) has a constant curvature if it has a nonnegative constant scalar curvature and sufficiently small L2-norm of trace-free Riemannian curvature tensor. Moreover, we get a gap theorem for (M4,g) with positive scalar curvature.
Closed Loop Recycling of Plastic Housing for Flat Screen TVs
2012-01-01
The treatment of the rapidly increasing number of End-of-Life (EoL) Flat screen Televisions (FTVs) presents major challenges and opportunities. Closing loops in plastic housing material flows remains a particular technical challenge because of the presence of additives, such as Flame Retardants (FR) in recovered housings. In the framework of a collaborative project PRIME with TP Vision the TV development site for Philips TVs and a Van Gansewinkel first level recycling plant, series of experim...
Square shaped flat-top beam in refractive beam shapers
Laskin, Alexander; Laskin, Vadim; Ostrun, Aleksei
2015-08-01
Lossless transformation of round Gaussian to square shaped flat-top collimated beam is important in building highpower solid state laser systems to improve optical pumping or amplification. There are industrial micromachining applications like scribing, display repair, which performance is improved when a square shaped spot with uniform intensity is created. Proved beam shaping solutions to these techniques are refractive field mapping beam shapers having some important features: flatness of output phase front, small output divergence, high transmittance, extended depth of field, operation with TEM00 and multimode lasers. Usual approach to design refractive beam shapers implies that input and output beams have round cross-section, therefore the only way to create a square shaped output beam is using a square mask, which leads to essential losses. When an input laser beam is linearly polarized it is suggested to generate square shaped flat-top output by applying beam shaper lenses from birefringent materials or by using additional birefringent components. Due to birefringence there is introduced phase retardation in beam parts and is realized a square shaped interference pattern at the beam shaper output. Realization of this approach requires small phase retardation, therefore weak birefringence effect is enough and birefringent optical components, operating in convergent or divergent beams, can be made from refractive materials, which crystal optical axis is parallel to optical axis of entire beam shaper optical system. There will be considered design features of beam shapers creating square shaped flat-top beams. Examples of real implementations and experimental results will be presented as well.
Preliminary design of large reflectors with flat facets
Agrawal, P. K.; Anderson, M. S.; Card, M. F.
1981-01-01
A concept for approximating curved antenna surfaces using flat facets is discussed. A preliminary design technique for determining the size of the reflector surface facets necessary to meet antenna surface accuracy requirements is presented. A proposed large microwave radiometer satellite (MRS) is selected as an application, and the far-field electromagnetic response of a faceted reflector surface is compared with that from a spherical reflector surface.
Closed Loop Recycling of Plastic Housing for Flat Screen TVs
Peeters, Jef; VANEGAS Paul; Devoldere, Tom; Dewulf, Wim; Duflou, Joost
2012-01-01
The treatment of the rapidly increasing number of End-of-Life (EoL) Flat screen Televisions (FTVs) presents major challenges and opportunities. Closing loops in plastic housing material flows remains a particular technical challenge because of the presence of additives, such as Flame Retardants (FR) in recovered housings. In the framework of a collaborative project PRIME with TP Vision the TV development site for Philips TVs and a Van Gansewinkel first level recycling plant, series of experim...
ETA INVARIANTS, DIFFERENTIAL CHARACTERS AND FLAT VECTOR BUNDLES
J.M.BISMUT
2005-01-01
The purpose of this paper is to give a refinement of the Atiyah-Singer families index theorem at the level of differential characters. Also a Riemann-Roch-Grothendieck theorem for the direct image of flat vector bundles by proper submersions is proved,with Chern classes with coefficients in C/Q. These results are much related to prior work of Gillet-Soule, Bismut-Lott and Lott.
Diffractive flat panel solar concentrators of a novel design.
de Jong, Ties M; de Boer, Dick K G; Bastiaansen, Cees W M
2016-07-11
A novel design for a flat panel solar concentrator is presented which is based on a light guide with a grating applied on top that diffracts light into total internal reflection. By combining geometrical and diffractive optics the geometrical concentration ratio is optimized according to the principles of nonimaging optics, while the thickness of the device is minimized due to the use of total internal reflection.
Velocity profiles of turbidity currents flowing over a flat bed
Kikura, H.; Murakawa, H.; Tasaka, Y.; Chamoun, Sabine; De Cesare, Giovanni; Schleiss, Anton
2016-01-01
Turbidity currents are the main source of suspended sediment transport in reservoirs and thus one of the main causes of sedimentation. One of the techniques used to avoid reservoir sedimentation is through venting of turbidity currents. In the framework of a research work on venting, velocity measurements of turbidity currents flowing on a flat bed are carried out using Ultrasonic Velocity Profilers (UVP). Five profilers of 4 MHz placed at different positions in an experimental flume provide ...
Relaxing the Parity Conditions of Asymptotically Flat Gravity
Compère, Geoffrey; Dehouck, François
2011-01-01
Four-dimensional asymptotically flat spacetimes at spatial infinity are defined from first principles without imposing parity conditions or restrictions on the Weyl tensor. The Einstein-Hilbert action is shown to be a correct variational principle when it is supplemented by an anomalous counter-term which breaks asymptotic translation, supertranslation and logarithmic translation invariance. Poincar\\'e transformations as well as supertranslations and logarithmic translations are associated wi...
Rocky Flats Plant Site Environmental Report: 1993 Highlights
1993-12-31
The Rocky Flats Plant Site Environmental Report provides summary information on the plant`s environmental monitoring programs and the results recorded during 1993. The report contains a compliance summary, results of environmental monitoring and other related programs, a review of environmental remediation activities, information on external gamma radiation dose monitoring, and radiation dose estimates for the surrounding population. This section provides an overview of these topics and summarizes more comprehensive discussions found in the main text of this annual report.
DECOMMISSIONING CHALLENGES AT THE ROCKY FLATS ENVIRONMENTAL TECHNOLOGY SITE
Dorr, K. A.; Hoover, J.
2002-02-25
This paper presents a discussion of the demolition of the Building 788 cluster at the Rocky Flats Environmental Technology Site (RFETS) in Golden, Colorado. The Building 788 Cluster was a Resource Conservation and Recovery Act (RCRA) permitted storage facilities and ancillary structures. Topics covered include the methods employed for Project Planning, Regulatory Compliance, Waste Management, Hazard Identification, Radiological Controls, Risk Management, Field Implementation, and Cost Schedule control, and Lessons Learned and Project Closeout.
COURSE REVERSAL OF TRACTOR UNIT ON FLAT PLOUGHING
V. Jatskevich
2012-01-01
Full Text Available The paper proposes a supportive maneuvering device for course reversal of a wheeled tractor unit on a smooth flat ploughing, its novelty is proved by a patent for an invention. Application of the supportive maneuvering device does not require any changes in design of commercial tractors. Theoretical and experimental investigations have been carried out in order to determine moments of resistance to course reversal according to minimum radius and time for such manouevre.
Quasi-Asimptotically Flat Spacetimes and Their ADM Mass
Nucamendi, U; Nucamendi, Ulises; Sudarsky, Daniel
1996-01-01
We define spacetimes that are asymptotically flat, except for a deficit solid angle $\\alpha$, and present a definition of their ``ADM'' mass, which is finite for this class of spacetimes, and, in particular, coincides with the value of the parameter $M$ of the global monopole spacetime studied by Vilenkin and Barriola . Moreover, we show that the definition is coordinate independent, and explain why it can, in some cases, be negative.
Local rainfall variations over small, flat, cultivated areas
Sandsborg, John
2011-01-01
An account is given of precipitation measurements on small, flat, cultivated areas carried out between 1957 and 1960 by means of very dense networks of precipitation stations. The precipitation distributions on single rainfalls were found to vary within large ranges. Clear distribution patterns appeared in the precipitation not only when the precipitation fell from convective clouds but also after frontal precipitation with almost no convection. The results from occasions with almost no conve...
An Incursion on Punching of Reinforced Concrete Flat Slabs
2009-01-01
Starting from the early 60s continuous studies have been made regarding punching of concrete flat slabs. The evolution of technology and calculus systems influenced this engineering branch. Nowadays is possible to account in structural analysis all the non-linear behaviour of reinforced and prestressed concrete and to get the most close structural response in comparison with the real behaviour. As a controversy matter, several tests and theories have been developed. Nowadays researchers try t...
MEASURING THE JET POWER OF FLAT-SPECTRUM RADIO QUASARS
Shabala, S. S.; Santoso, J. S. [School of Mathematics and Physics, University of Tasmania, Private Bag 37, Hobart, TAS 7001 (Australia); Godfrey, L. E. H. [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, Western Australia 6845 (Australia)
2012-09-10
We use frequency-dependent position shifts of flat-spectrum radio cores to estimate the kinetic power of active galactic nucleus (AGN) jets. We find a correlation between the derived jet powers and AGN narrow-line luminosity, consistent with the well-known relation for radio galaxies and steep spectrum quasars. This technique can be applied to intrinsically weak jets even at high redshift.
The BTZ black hole as a Lorentz-flat geometry
Alvarez, Pedro D., E-mail: alvarez@physics.ox.ac.uk [Rudolf Peierls Centre for Theoretical Physics, University of Oxford (United Kingdom); Pais, Pablo, E-mail: pais@cecs.cl [Centro de Estudios Científicos (CECs), Av. Arturo Prat 514, Valdivia (Chile); Universidad Andrés Bello, Av. República 440, Santiago (Chile); Rodríguez, Eduardo, E-mail: eduarodriguezsal@unal.edu.co [Departamento de Matemática y Física Aplicadas, Universidad Católica de la Santísima Concepción, Concepción (Chile); Salgado-Rebolledo, Patricio, E-mail: pasalgado@udec.cl [Centro de Estudios Científicos (CECs), Av. Arturo Prat 514, Valdivia (Chile); Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Physique Théorique et Mathématique, Université Libre de Bruxelles and International Solvay Institutes, Campus Plaine C.P. 231, B-1050 Bruxelles (Belgium); Zanelli, Jorge, E-mail: z@cecs.cl [Centro de Estudios Científicos (CECs), Av. Arturo Prat 514, Valdivia (Chile); Universidad Andrés Bello, Av. República 440, Santiago (Chile)
2014-11-10
It is shown that 2+1 dimensional anti-de Sitter spacetimes are Lorentz-flat. This means, in particular, that any simply-connected patch of the BTZ black hole solution can be endowed with a Lorentz connection that is locally pure gauge. The result can be naturally extended to a wider class of black hole geometries and point particles in three-dimensional spacetime.
The Self-Drying Concept for Flat Roofs
Korsgaard, Vagn; Bunch-Nielsen, Tommy; Rode, Carsten
1996-01-01
Moisture in flat roof systems with an insulation layer has been a long-standing issue for the roof industry. It is now realised, that it is unrealistic and too costly to try to completely keep moisture from entering a roof assembly during its service life. The approach, therefore, should be to ke...... cold- and warm deck roof systems in climate zones where a vapor retarder is needed, if the traditional water proof vapor retarder is substituted by a water permeable vapor retarder....
Relationship between Nutritional Status and Flat Foot in Children
Joyce Phua Pau Fung; Yoyos Dias Ismiarto; Wulan Mayasari
2017-01-01
Background: Pediatric flatfoot has been reported as the highest clinical complains for foot problems in pediatric department. Nutritional status has showed great influence on the occurrence of flat foot. There are many debates regarding whether underweight or overweight children are more prone to flatfoot. The aim of this study was to analyze the relationship between nutritional status and flatfoot in children. Methods: A cross sectional study was conducted from July to October 2015 in 3 ...
Plasma technology and its use in flat panel digital radiography.
Zur, Albert
2010-01-01
Plasma DR technology is used to produce a cost effective flat panel x-ray detector that acquires digital x-ray images with excellent diagnostic quality. The detector is radiation hard and permanently zero defect, with a full virtual pixel matrix that has no dead lines, pixels, or dead pixel clusters. The technology also allows the full potential of large area amorphous Selenium imaging to finally be realized (see Figure 4).
EM Scattering from Conducting Flat Plates Coated with Thin RAM
无
2002-01-01
According to the equivalence principles, high frequency approximation and boundary conditions, a method has been developed to deal with the EM scattering by a rectangular conducting flat plate coated with uniaxial anisotropic radar absorbing material (RAM). The simple and effective method is available to the system of RCS prediction in which the large complex targets modeled by facets and wedges. Numerical results show some properties of EM scattering by conducting plate coated with thin uniaxial anisotropic RAM.
Curie depth vs. flat subduction in Central Mexico
Manea, Marina; Constantin Manea, Vlad
2010-05-01
Forearcs located above active subduction zones are generally characterized by low heat flow values, and this is considered a consequence of the subduction of cold slabs beneath continental plates. In the case of Central Mexico, the geometry of the subducting Cocos plate is quite unusual, the slab runs flat for several hundreds of kilometers before plunging into the asthenosphere. This particular geometry has a strong influence on the temperature distribution of the overriding plate where very low heatflow values are recorded (15-30 mW/m2). In this paper we use the aeromagnetic map of Mexico in order to infer the maximum depth of magnetic source, regarded as Curie depth and corresponding to a temperature of 575-600C°. Our spectral analysis revealed the existence of a deep magnetic source (30-40 km). We compare these results with the thermal structure associated with flat slab subduction in the area. We obtained a good agreement between the two estimates and we conclude that flat slab subduction in Central Mexico controls the maximum depth of magnetic sources in the overriding plate.
Unfolding X-ray spectra using a flat panel detector.
Gallardo, Sergio; Juste, Belén; Pozuelo, Fausto; Ródenas, José; Querol, Andrea; Verdú, Gumersindo
2013-01-01
It is difficult to measure the energy spectrum of X-ray tubes due to the pile up effect produced by the high fluence of photons. Using attenuating materials, appropriate detector devices and the Monte Carlo method, primary X-ray spectrum of these devices can be estimated. In this work, a flat panel detector with a PMMA wedge has been used to obtain a dose curve corresponding to certain working conditions of a radiodiagnostic X-ray tube. The relation between the dose curve recorded by the flat panel and the primary X-ray spectrum is defined by a response function. Normally this function can be approximated by a matrix, which can be obtained by means of the Monte Carlo method. Knowing the measured dose curve and the response matrix, the primary X-ray spectrum can be unfolded. However, there are some problems that strongly affect the applicability of this method: i.e. technical features of the flat panel and inherent characteristics of the involved radiation physics (ill-posed problem). Both aspects are analyzed in this work, concluding that the proposed method can be applied with an acceptable accuracy for spectra without characteristic lines, for instance, tungsten anode in the 50-70 kVp range.
Field Flatness Tuning for PEFP 100 MeV DTL
Kim, Han-Sung; Kwon, Hyeok-Jung; Seol, Kyung-Tae; Kim, Dae-Il; Cho, Yong-Sub [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2008-05-15
A conventional 100 MeV drift tube linac is under development for Proton Engineering Frontier Project. Currently the proton linac up to 20 MeV, which consists of injector, 3 MeV RFQ and 20 MeV DTL is completed. To accelerate the proton beam up to 100 MeV additional 7 DTL tanks are required. The DTL should be tuned after fabrication and alignment of the drift tube inside the tank to meet the requirements from the beam dynamics. Tuning process includes the resonant frequency tuning, field flatness tuning and tilt sensitivity tuning. The tuning goal for the field flatness tuning is less than {+-}2% in field uniformity throughout the DTL tank with less than {+-}% standard deviation. A non-uniform field profile caused by the machining errors and alignment errors can be made uniform through the slug tuner adjustment. This procedure requires the field profile measurements and several iterations between the field profile measurements and adjustment. The methods and the results of the DTL field flatness tuning will be reported in this presentation.
The Atomic Views of Flat Supply Chains in China
Sekhar Chattopadhyay
2010-09-01
Full Text Available China's domestic supply chain networks are getting flat and unbalanced despite its spectacular growth and rise to the enviable position in the global supply chain arena in recent times. The aftermath of continued investment explosion, especially in the coastal areas of the mainland, calls for an interwoven relationship of Chinese companies with the rest of the global supply chains. However, with new information and communication technologies, the real-time problems arising from this flattened supply chains are much more complex, multifaceted and multidimensional. China needs to re-think and re-focus on better alignment to the western values and cultures while managing its global business activities. This paper discusses four recently developed enterprise models in the light of several case studies conducted recently in Australia, China and India to characterise these new flat supply chains: People-Centric, Molecular Organization, Globally Dispersed and Disaggregated Value Chain. These, apparently different but inherently similar models have a vibrant architecture and system behaviour in their core and propose an alternative approach to address challenges of unbalanced domestic flat supply chains in China and helps the Chinese manufacturers to explore an approach to embrace Western values and cultures by enlarging their sphere of influence.
Titanium based flat heat pipes for computer chip cooling
Soni, Gaurav; Ding, Changsong; Sigurdson, Marin; Bozorgi, Payam; Piorek, Brian; MacDonald, Noel; Meinhart, Carl
2008-11-01
We are developing a highly conductive flat heat pipe (called Thermal Ground Plane or TGP) for cooling computer chips. Conventional heat pipes have circular cross sections and thus can't make good contact with chip surface. The flatness of our TGP will enable conformal contact with the chip surface and thus enhance cooling efficiency. Another limiting factor in conventional heat pipes is the capillary flow of the working fluid through a wick structure. In order to overcome this limitation we have created a highly porous wick structure on a flat titanium substrate by using micro fabrication technology. We first etch titanium to create very tall micro pillars with a diameter of 5 μm, a height of 40 μm and a pitch of 10 μm. We then grow a very fine nano structured titania (NST) hairs on all surfaces of the pillars by oxidation in H202. In this way we achieve a wick structure which utilizes multiple length scales to yield high performance wicking of water. It's capable of wicking water at an average velocity of 1 cm/s over a distance of several cm. A titanium cavity is laser-welded onto the wicking substrate and a small quantity of water is hermetically sealed inside the cavity to achieve a TGP. The thermal conductivity of our preliminary TGP was measured to be 350 W/m-K, but has the potential to be several orders of magnitude higher.
Experimental analysis of a flat heat pipe working against gravity
Esarte, J.; Domiguez, M. [Universidad Publica de Navarra (Spain). Dept. of Mechanical Engineering
2003-09-01
Thermoelectric refrigeration always presents a heat flux addressing problem (constriction resistance) and it is a subject that has extensively been studied and analysed [closed form equation for thermal constriction/spreading resistances with variable resistances boundary conditions, IEPS Conference, 1994]. In previous works [Issues of the heat dissipation coming from a big surface through a much smaller one, 20th International Conference on Thermoelectrics, Beijing-China, 2001], a device (flat heat pipe) capable of addressing the heat flux has been theoretically and experimentally developed to reduce the so called constriction resistance (the lower the constriction resistance the higher the thermoelectric module performance). This work presents the experimental results of the constriction resistance for different prototypes of flat heat pipe and investigates if they are in agreement with the theoretical predictions. It also shows the influence of certain parameters on the constriction resistance. The results have later been compared with those obtained for a flat plate in order to check whether or not the device improves the thermoelectric module performance. A brief description of the device operation is also given. (Author)
Optimal Motion Planning for Differentially Flat Underactuated Mechanical Systems
HE Guangping; GENG Zhiyong
2009-01-01
Underactuated mechanical system has less independent inputs than the degrees of freedom(DOF) of the mechanism. The energy efficiency of this class of mechanical systems is an essential problem in practice. On the basis of the sufficient and necessary condition that concludes a single input nonlinear system is differentially flat, it is shown that the flat output of the single input tmderactuated mechanical system can be obtained by finding a smooth output function such that the relative degree of the system equals to the dimension of the state space. If the fiat output of the underactuated system can be solved explicitly, and by constructing a smooth curve with satisfying given boundary conditions in flat output space, an energy efficiency optimization method is proposed for the motion planning of the differentially fiat underactuated mechanical systems. The inertia wheel pendulum is used to verify the proposed optimization method, and some numerical simulations show that the presented optimal motion planning method can efficaciously reduce the energy cost for given control tasks.
Flat coordinates for Saito Frobenius manifolds and String theory
Belavin, Alexander; Kononov, Yakov
2015-01-01
It was shown in \\cite{DVV} for $2d$ topological Conformal field theory (TCFT) \\cite{EY,W} and more recently in \\cite{BSZ}-\\cite{BB2} for the non-critical String theory \\cite{P}-\\cite{BAlZ} that a number of models of these two types can be exactly solved using their connection with the Frobenius manifold (FM) structure introduced by Dubrovin\\cite{Dub}. More precisely these models are connected with a special case of FMs, so called Saito Frobenius manifolds (SFM)\\cite{Saito} (originally called Flat structure together with the Flat coordinate system), which arise on the space of the versal deformations of the isolated Singularities after choosing of a suitabe so-called Primitive form, and which also arises on the quotient spaces by reflection groups. In this paper we explore the connection of the models of TCFT and non-critical String theory with SFM. The crucial point for obtaining an explicit expression for the correlators is finding the flat coordinates of SFMs as functions of the parameters of the deformed s...
Pulsed dye laser treatment for facial flat warts.
Grillo, E; Boixeda, P; Ballester, A; Miguel-Morrondo, A; Truchuelo, T; Jaén, P
2014-01-01
The facial flat wart is not only a contagious viral disease, but also a cause of a distressing cosmetic problem. Although there are many therapeutic options, including salicylic acid, imiquimod, cryotherapy, retinoids, intralesional immunotherapy, and topical 5-aminolevulinic acid photodynamic therapy among others, no monotherapy has been proved to achieve complete remission in every case. Treatment with pulsed dye laser (PDL) seems to be a promising therapeutic option. To assess the efficacy and safety of PDL in a series of patients with viral flat warts on the face, in this prospective study, 32 patients were treated with PDL at 595-nm wavelength, a laser energy density of 9 or 14 J/cm(2) with a spot size of 7 or 5 mm, respectively, with air cooling and a pulse duration of 0.5 millisecond. A complete response was noted in 14 patients (44%), and an excellent response was observed in 18 patients (56%) with 1-year follow-up, with only four recurrences. No significant side effects were reported except intense transitory purpuric response. We consider that PDL is a good option of treatment for flat warts on the face due to its good clinical results, fast response, and low incidence of side effects. © 2013 Wiley Periodicals, Inc.
Gravitational multi-soliton solutions on flat space
Chen, Yu
2015-01-01
It is well-known that, for even n, the n-soliton solution on the Minkowski seed, constructed using the inverse-scattering method (ISM) of Belinski and Zakharov (BZ), is the multi-Kerr-NUT solution. We show that, for odd n, the natural seed to use is the Euclidean space with two manifest translational symmetries, and the n-soliton solution is the accelerating multi-Kerr-NUT solution. We thus define the n-soliton solution on flat space for any positive integer n. It admits both Lorentzian and Euclidean sections. In the latter section, we find that a number say m of solitons can be eliminated in a non-trivial way, by appropriately fixing their corresponding so-called BZ parameters. The resulting solutions, which may split into separate classes, are collectively denoted as [n-m]-soliton solutions on flat space. We then carry out a systematic study of the n- and [n-m]-soliton solutions on flat space. This includes, in particular, an explicit presentation of their ISM construction, an analysis of their local geomet...
Elastic tripping analysis of corroded flat-bar stiffeners
Ahmad Rahbar-Ranji
2016-12-01
Full Text Available Tripping of stiffeners is one of the buckling modes of stiffened panel which could rapidly lead to its catastrophic failure. Loss of thickness in web and flange due to corrosion reduces elastic buckling strength of stiffeners. It is common practice to assume a uniform thickness reduction for general corrosion. Since the real corroded plate has rough surfaces, to estimate the remaining strength of corroded structures, typically a much higher level of accuracy is required. There is a little study on strength analysis of corroded plates with rough surface especially as a function of corrosion degrees. The aim of present work is to analyze elastic tripping stress of flat bar stiffeners with both-sided corroded surfaces. Undulated surfaces are generated based on the power spectrum of the corroded surface. Elastic tripping stress is calculated using ANSYS code. Finite elements method is employed to analyze elastic tripping stress of corroded steel flat bars with both sided rough surfaces. Comparing the results with elastic tripping strength of corroded flat bars with uniform thickness, a reduction factor is proposed. It is found that reduction factor of buckling strength by uniform thickness assumption is overestimated.
Mechanical Normal Forms of Knots and Flat Knots
Sossinsky, A B
2010-01-01
A new type of knot energy is presented via real life experiments involving a thin resilient metallic tube. Knotted in different ways, the device mechanically acquires a uniquely determined (up to isometry) normal form at least when the original knot diagram has a small number of crossings, thus outperforming the famous M\\"obius energy due to Jun O'Hara and studied by Michael Freedman et al. Various properties of the device are described (under certain conditions it does the Reidemeister and Markov moves, it beautifully performs the Whitney trick by uniformizing its own local curvature). If the device is constrained between two parallel planes (e.g. glass panes), it yields a real life model of a flat knot (class of knot diagrams equivalent under Reidemeister $\\Omega_2$ and $\\Omega_3$ moves) also leading to uniquely determined "flat normal forms" (for a small number of crossing points of the given flat knot diagram). The paper concludes with two mathematical theorems, one reducing the knot recognition problem t...
Map of mixed prairie grassland vegetation, Rocky Flats, Colorado
Clark, S J.V.; Webber, P J; Komarkova, V; Weber, W A
1980-01-01
A color vegetation map at the scale of 1:12,000 of the area surrounding the Rocky Flats, Rockwell International Plant near Boulder, Colorado, provides a permanent record of baseline data which can be used to monitor changes in both vegetation and environment and thus to contribute to future land management and land-use policies. Sixteen mapping units based on species composition were identified, and characterized by two 10-m/sup 2/ vegetation stands each. These were grouped into prairie, pasture, and valley side on the basis of their species composition. Both the mapping units and these major groups were later confirmed by agglomerative clustering analysis of the 32 vegetation stands on the basis of species composition. A modified Bray and Curtis ordination was used to determine the environmental factor complexes controlling the distribution of vegetation at Rocky flats. Recommendations are made for future policies of environmental management and predictions of the response to environmental change of the present vegetation at the Rocky Flats site.
Use of the flat dilatometer (DMT) in landslides
Amoroso, Sara; Monaco, Paola
2016-04-01
During the last decades we have assisted at a considerable shift from laboratory testing to in situ testing to the point that, today, in situ testing often represent the major part of a geotechnical investigation. Recommendations given in recent State-of-the-Art papers indicate that direct-push in situ tests, such as the Seismic Cone Penetration Test (SCPT) and the Seismic Dilatometer Test (SDMT), are fast and very convenient tests for routine site investigations. The aim of this paper is to describe the use of the flat dilatometer test (DMT) in landslide diagnosis and monitoring. In particular, a method is presented for detecting slip surfaces in overconsolidated clay slopes based on the inspection of the profiles of the horizontal stress index KD from DMT, as developed by Totani et al. (1997). In addition, the relaxation of the in situ horizontal stress σh, estimated from DMT, helps to locate a landslide. The paper illustrates by using different examples the capability of SDMT to identify the shear zones left remoulded by the occurrence of a landslide. Keywords: flat dilatometer, horizontal stress index, in situ horizontal stress References Totani G., Calabrese M., Marchetti S., Monaco, P. (1997). Use of in situ flat dilatometer (DMT) for ground characterization in the stability analysis of slopes. Proceeding of 14th International Conference on Soil Mechanics and Foundation Engineering, Hamburg, September 1997, vol. 1, pp. 607-610.
Flatness and Edge Drop Decoupling Control for the Tandem Cold Rolling Mill
Zhou, Xiao-Min; Yue, Xiao-Xue
2016-05-01
The flatness and edge drop is a strong-coupled multivariable control system, so realizing the decoupling control of them is one of the most important issues to achieve the highprecision control. In this paper, the modelling of system and decoupling control method of flatness and edge drop are analyzed. Simulation results represent that the flatness and edge drop control is decoupled to improve the control performance of flatness and edge drop.
A New Proof of the Theorem: Harmonic Manifolds with Minimal Horospheres are Flat
Hemangi M Shah
2014-08-01
In this note we reprove the known theorem: Harmonic manifolds with minimal horospheres are flat. It turns out that our proof is simpler and more direct than the original one. We also reprove the theorem: Ricci flat harmonic manifolds are flat, which is generally affirmed by appealing to Cheeger–Gromov splitting theorem. We also confirm that if a harmonic manifold has same volume density function as $\\mathbb{R}^n$, then is flat.
A low density, high stiffness flat loudspeaker with improved sound frequency response
Ho, J.; Berkhoff, Arthur P.
2013-01-01
This paper presents a novel flat loudspeaker with improved sound frequency response. Flat loudspeakers provide advantages of compact dimensions and high durability. Known flat loudspeaker technology is based on high modal density. However, the resonances in the panel are complex and difficult to
78 FR 31577 - Diffusion-Annealed, Nickel-Plated Flat-Rolled Steel Products From Japan
2013-05-24
...)] Diffusion-Annealed, Nickel-Plated Flat-Rolled Steel Products From Japan Determination On the basis of the... reason of imports from Japan of diffusion-annealed, nickel-plated flat-rolled steel products, provided... diffusion-annealed, nickel-plated flat-rolled steel products from Japan. Accordingly, effective March...
78 FR 15376 - Determinations: Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea
2013-03-11
... COMMISSION Determinations: Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea On the basis... Korea and the antidumping duty orders on corrosion-resistant carbon steel flat products from Germany and... Corrosion-Resistant Carbon Steel Flat Products from Germany and Korea: Investigation Nos. 701-TA-350 and...
Liquid bridge force between two unequal-sized spheres or a sphere and a plane
You chuan Chen; Yong zhi Zhao; Hong li Gao; Jin yang Zheng
2011-01-01
Liquid bridge force acting between wet particles is an important property in particle characterization.This paper deals with liquid bridge force between either two unequal-sized spherical particles or a sphere and a flat plate under conditions where gravitational effect arising from bridge distortion is negligible.In order to calculate the force of the liquid bridge efficiently and accurately,expressions of liquid configuration and liquid bridge force were derived by building a mechanical model,which assumes the liquid bridge to be circular in shape between either two unequal-sized spheres or a sphere and a plane.To assess the accuracy of the numerical results of the calculated liquid bridge forces,they were compared to the published experimental data.
Scaling output energy in a diode-end-pumped passively Q-switched laser with a flat-flat resonator
Tang, C. Y.; Huang, Y. J.; Liang, H. C.; Chen, Y. F.; Su, K. W.
2017-01-01
The spatial and temporal behaviors in a diode-end-pumped passively Q-switched laser with a flat-flat resonator are systematically explored as a function of the cavity length. A Nd:YAG/Cr4+:YAG miniature laser is experimentally used to show that the scale-up of the pulse energy without the higher-order transverse modes can be practically realized by optimizing the cavity length as a function of the pump size. A theoretical analysis is performed to confirm the experimental results. The extracavity second harmonic generation is experimentally conducted to demonstrate the usefulness of the laser design. PACS number(s): 42.60.Gd Q-switching; 42.55.Xi Diode-pumped lasers; 42.55.-f Lasers; 42.65.Sf Dynamics of nonlinear optical systems; optical instabilities, optical chaos and complexity, and optical spatiotemporal dynamics.
Numerical Modeling of Flat Slab Formation in Central Chile
Manea, M.; Perez-Gussinye, M.; Manea, V.; Fernandez, M.
2009-12-01
Subduction of oceanic plates beneath large continental masses is a rare process and at present it occurs only along western South America and Central Mexico. Likewise, flat subduction, understood here as where the slab enters at a normal angle and reverses its curvature to flatten at ~70-120 km depth, only occurs at present beneath South America. In general, the angle at which subduction occurs in the depth range of ~100 to ~200 km reflects the balance between negative buoyancy of the slab, elastic resistance of the slab to change the angle of subduction, and non-hydrostatic pressure forces induced by subduction-driven flow within the asthenosphere. The latter force, known as suction force, acts to prevent the slab from sinking into the mantle, and its magnitude increases with increasing subduction velocity, narrowness and viscosity decrease of the mantle wedge [Manea and Gurnis, 2007]. Recent observations show that the upper plate structure varies along the Andean margin, indicating that it is thicker and stronger above flat subduction zones and suggesting a correlation between upper plate structure and subduction angle [Pérez-Gussinyé et al., 2008; Booker et al., 2004]. In this study we use numerical models to explore the extent to which upper plate structure, through its influence on asthenospheric wedge shape and viscosity, can affect the angle of subduction. We test for which upper plate thickness and asthenospheric viscosity repeated cycles of steep and flat subduction are reproduced and compare our results to estimations of lithospheric thickness and the duration of flat and steep subduction cycles hypothesized along the Andean margin. Our models are constrained by realistic plate velocities in hot spot reference frame for both Nazca and South American plates [Muller et al., 2008], the Miocene-Present shortening for the Andes [Schelart et al., 2007] and realistic Nazca plate age distribution [Sdrolias and Muller, 2006]. Using the finite element package
Development of ramp-flat structures during Aegean extension
Brun, Jean-Pierre; Sokoutis, Dimitrios
2014-05-01
Low-angle extensional shear is frequently observed in the Aegean metamorphic rocks. This deformation is commonly interpreted as being related to detachment at crustal scale, yet it often corresponds to ramp-flat extensional systems that, at many places, control the deposition of Neogene sedimentary basins. From a mechanical point of view, the development of a ramp-flat structure requires the presence of weak layers that can be activated as décollement between stronger rocks units. In the Aegean, the décollement generally develops within the upper brittle crust (i.e. with temperatures lower than about 400°C) that consists in recently exhumed metamorphic rocks. The process by which, these layers become weak enough to form efficient décollements in extension is somewhat intriguing and not well understood. In this contribution we examine the particular case of ramp-flat structures of the Southern Rhodope Core Complex that controlled the deposition of late Miocene to Pleistocene sediments in continental and marine basins. Field evidence is used to argue that the décollement corresponds to marble layers that separate orthogneisses at 2-3 km depth within an upper brittle crust whose thickness is around 5 km. Field observation and stable isotope measurements suggest that the ramp-flat structure observed on the island of Thassos occurred in a marble unit rich in fluids at a temperature of around 200°C. Using laboratory experiments, we explore the geometry of extensional structures (fault systems, rollovers, piggy-back basins…) that can develop at crustal-scale as a function of: i) décollement depth and dip, ii) number of décollements, and iii) strength contrast, between the décollement and overlying strong units. The results are compared with the situation observed in the Southern Rhodope Core Complex. We are convinced that the principles of ramp-flat extension discussed here have a strong potential of application in many other orogenic domains affected by large
A STUDY ON EQUILIBRIUM COASTAL PROFILES OF THE CLOSE TIDAL FLAT--A Case Study of Fengxian Tidal Flat
无
2002-01-01
The article analyses the temporal-spatial changes of profiles by EOF (Empirical Orthogonal Function) analy-sis and DTM analysis of GIS. These profiles, which are not affected by engineering, are chosen from the coast with succes-sive field monitoring data from 1990 to 1999. Temporal and spatial EOF indicates the obvious stability of coast profile param-eters in Fengxian tidal flat. In spatial scale, high tidal flats and deep-water terraces are in a balance state while upperclino with steep slopes are sensitive and the stability is easy to be destroyed. In temporal scale, the erosion and deposi-tion in this area are kept in balance in a whole. There are almost no change below -8 - -9.5m. At the same time, it isthe lower limit of tidal affection and the erosion and deposition process from it to high tidal flat keep in balance for manyyears. So the closure depth is appointed to from -8m to -9.5 m (Wusong datum mark).
CASH AND LIQUIDITY/LIQUIDITY AND LIQUIDITY RATIO
BEATRIX LIGHEZAN BREUER
2012-12-01
Full Text Available The present paper aims to present the correlation as well as the differences between liquidity/cash and liquidity ratio in terms of economic entities. Researches on this topic are based on the opinions of some specialists in accounting and in the economic-financial analysis, as well as on the national legal stipulations and the ones set out in the International Accounting Standards, the Financial report, respectively. The object of this paper is represented by the correlation between liquidity/cash and liquidity ratios representing the liquidity as current assets, assets implied in the determination of liquidity ratios. The end of the paper consists of the conclusions drawn from the issues presented in the paper but also our views on this research topic.
Solutions to the Quasi-flatness and Quasi-lambda Problems
Barrow, John D; Barrow, John D.; Magueijo, Joao
1999-01-01
Big Bang models of the Universe predict rapid domination by curvature, a paradox known as the flatness problem. Solutions to this problem usually leave the Universe exactly flat for every practical purpose. Explaining a nearly but not exactly flat current Universe is a new problem, which we label the quasi-flatness problem. We show how theories incorporating time-varying coupling constants could drive the Universe to a late-time near-flat attractor. A similar problem may be posed with regards to the cosmological constant as well.
The study method of estimation tidal flat with remote sensing waterlines
Gao, Zhiqiang; Liu, Xiangyang; Zhang, Yuanyuan; Liu, Chaoshun; Sun, Zhibin
2016-09-01
A tidal flat, the important potential land resource, is the sensitive area of intersection between the sea and the land. With Chinese HJ-1A/B remote sensing images of 2014 as data sources, based on the definition of a tidal flat, using DSAS software and Jenks Natural Breaks classification method synthetically, a more reasonable and accurate method of extracting tidal flat was imposed. In addition, the Bohai Rim was taken as an example to carry out investigation on the current situation of tidal flat. This paper can provide basic date and scientific evidence for rational utilization and sustainable development of tidal flat.
Experimental investigation of liquid jet injection into Mach 6 hypersonic crossflow
Beloki Perurena, J.; Asma, C.O.; Theunissen, R.; Chazot, O.
2008-01-01
The injection of a liquid jet into a crossing Mach 6 air flow is investigated. Experiments were conducted on a sharp leading edge flat plate with flush mounted injectors. Water jets were introduced through different nozzle shapes at relevant jet-to-air momentum-flux ratios. Sufficient temporal
Experimental investigation of liquid jet injection into Mach 6 hypersonic crossflow
Beloki Perurena, J.; Asma, C.O.; Theunissen, R.; Chazot, O.
2008-01-01
The injection of a liquid jet into a crossing Mach 6 air flow is investigated. Experiments were conducted on a sharp leading edge flat plate with flush mounted injectors. Water jets were introduced through different nozzle shapes at relevant jet-to-air momentum-flux ratios. Sufficient temporal resol
Flat medial-lateral conformity in total knee replacements does not minimize contact stresses.
Rawlinson, Jeremy J; Bartel, Donald L
2002-01-01
The potential for wear in UHMWPE components for total knee replacements can be reduced by decreasing the stresses and strains arising from tibial-femoral contact. The conformity of the articular surfaces has a large effect on the resultant stresses, and components that achieve flat medial-lateral contact have been assumed to produce the lowest stresses due to their perfect conformity. We computed the stresses arising from curved and flat contact on a half-space using two-dimensional, plane strain elasticity solutions and finite element analyses to compare the performance of curved and flat indenters. These indenters were represented by a polynomial so the profiles could be continuously varied from curved to flat. Curved contact resulted in maximum stresses at the center of contact, while flat contact produced maximum stresses at the edge of contact. In addition, three contemporary tibial configurations (flat-on-flat, curved-on-flat, and curved-on-curved geometries) were analyzed using the finite element method with nonlinear material properties. The maximum contact stress, von Mises stress, and von Mises strain were lowest for the curved-on-curved model. The other configurations resulted in higher contact stresses, von Mises stresses, and von Mises strains. The perfect conformity arising from flat contact did not reduce the contact stresses in the UHMWPE component. The tensile stresses, however, were lowest for the flat-on-flat geometry compared with the other two configurations. Relating these distinct differences could prove useful in interpretation of data from simulator and retrieval studies.
Flat Array Antennas for Ku-Band Mobile Satellite Terminals
Roberto Vincenti Gatti
2009-01-01
Full Text Available This work presents the advances in the development of two innovative flat array antennas for Ku-band mobile satellite terminals. The first antenna is specifically conceived for double-deck trains to allow a bi-directional high data rate satellite link. The available circular surface (diameter 80 cm integrates both a transmitting and a receiving section, operating in orthogonal linear polarizations. The TX frequency range is fully covered while the RX bandwidth is around 1 GHz arbitrarily allocated on the DVB range depending on requirements. The beam is steered in elevation through a phased array architecture not employing costly phase shifters, while the steering in azimuth is mechanical. Active BFNs allow excellent performance in terms of EIRP and G/T, maintaining extremely low profile. High antenna efficiency and low fabrication cost are ensured by the employment of innovative SIW (Substrate Integrated Waveguide structures. The second antenna, receiving-only, is designed for radio/video streaming services in mobile environment. Full DVB coverage is achieved thanks to cavity-backed patches operating in double linear polarization. Two independent broadband active BFNs allow simultaneous reception of both polarizations with full tracking capabilities and a squintless beam steering from 20∘ to 60∘ in elevation. A minimum gain of 20 dBi and G/T >−3 dB/∘K are achieved, while maintaining extremely compact size and flat profile. In the design of both antennas fabrication cost is considered as a driving factor, yet providing high performance with a flat profile and thus resulting in a great commercial potentiality.
Relationship between Nutritional Status and Flat Foot in Children
Joyce Phua Pau Fung
2017-03-01
Full Text Available Background: Pediatric flatfoot has been reported as the highest clinical complains for foot problems in pediatric department. Nutritional status has showed great influence on the occurrence of flat foot. There are many debates regarding whether underweight or overweight children are more prone to flatfoot. The aim of this study was to analyze the relationship between nutritional status and flatfoot in children. Methods: A cross sectional study was conducted from July to October 2015 in 3 primary schools in Kecamatan Jatinangor. There were 259 children of grade 4 to 5 included in this study. Flatfoot screening was based on measurement of footprint and calculation using Chippaux-smirak index (CSI. The height and weight of children were measured to obtain their Body Mass Index (BMI. Nutritional status was classified based on CDC BMI-for-age growth charts. Analysis was done using chi-square test. Results: There was significant association between nutritional status and flatfoot with p value<0.001.The prevalence of flatfoot in children grade 4to5is40%. When compared to the normal weight children, the overweight children showed prevalence ratio of 1.97(95% CI:1.47 to 2.64 while the underweight children showed prevalence ratio of 1.34 (95% CI:1.78 to 2.25.This stated that the risk of developing flat foot was higher in overweight children. Conclusions: There is significant association between nutritional status with children grade4 to 5. Overweight children are more prone to flat foot.
Do LCDs have a chance to keep a leading position on flat panel display market?
Zielinski, Jerzy; Olifierczuk, Marek
2004-09-01
A lot of significant discoveries and inventions in the field of technology of displays were made in the latter part of the twentieth century. Apart from well-known CRT, the plasma-, luminescence- and liquid crystal-displays are commercially available. One can notice that a leading position on that flat panel displays market belong to LCD. But the progress in Organic LED materials and devices is impressive. Threshold voltage for light emission have fallen from several thousands V to just 2 - 3 V for today's OLEDs (polymer and small molecule). Luminous efficiency has increased from 0,01 to more than 10 lm/W. These improvements have brought PLED technology to the point where serious consideration is being given to OLED graphic and video display product. The question given some years ago by Dr. M. E. Becker, [Display Metrology and Systems]: "...is the current OLED enthusiasm justified because OLED displays feature significant improvements in visual and ergonomic performance, and because they are much cheaper to manufacture; Or it is just another hope for those who missed the LCD train?...," is trite. During SID Conference in Baltimore in 2003 two companies claiming to have built the largest organic LED. International Display Technology demonstrated a 20 inch display driven by "super amorphous silicon" technology; Sony showed off its 24 inch screen, which consists of a 2x2 tiled array of OLED displays. The presented work will be oriented towards specifying the characteristic features of liquid crystal and electro luminescence organic compounds which make these groups of displays so attractive and prospective among other imagery systems devices existing nowadays.
Thermal performance of a flat polymer heat pipe heat spreader under high acceleration
Oshman, Christopher; Li, Qian; Liew, Li-Anne; Yang, Ronggui; Lee, Y. C.; Bright, Victor M.; Sharar, Darin J.; Jankowski, Nicholas R.; Morgan, Brian C.
2012-04-01
This paper presents the fabrication and application of a micro-scale hybrid wicking structure in a flat polymer-based heat pipe heat spreader, which improves the heat transfer performance under high adverse acceleration. The hybrid wicking structure which enhances evaporation and condensation heat transfer under adverse acceleration consists of 100 µm high, 200 µm wide square electroplated copper micro-pillars with 31 µm wide grooves for liquid flow and a woven copper mesh with 51 µm diameter wires and 76 µm spacing. The interior vapor chamber of the heat pipe heat spreader was 30×30×1.0 mm3. The casing of the heat spreader is a 100 µm thick liquid crystal polymer which contains a two-dimensional array of copper-filled vias to reduce the overall thermal resistance. The device performance was assessed under 0-10 g acceleration with 20, 30 and 40 W power input on an evaporator area of 8×8 mm2. The effective thermal conductivity of the device was determined to range from 1653 W (m K)-1 at 0 g to 541 W (m K)-1 at 10 g using finite element analysis in conjunction with a copper reference sample. In all cases, the effective thermal conductivity remained higher than that of the copper reference sample. This work illustrates the possibility of fabricating flexible, polymer-based heat pipe heat spreaders compatible with standardized printed circuit board technologies that are capable of efficiently extracting heat at relatively high dynamic acceleration levels.
Collisions in piecewise flat gravity in 3+1 dimensions
Van de Meent, Maarten, E-mail: M.vandeMeent@uu.n [Institute for Theoretical Physics and Spinoza Institute, Utrecht University, PO Box 80.195, 3508 TD Utrecht (Netherlands)
2010-07-21
We consider the (3 + 1)-dimensional locally finite gravity model proposed by 't Hooft (2008 Found. Phys. 38 733-57). In particular we revisit the problem of resolving collisions of string defects. We provide a new geometric description of the configurations of strings using piecewise flat manifolds and use it to resolve a more general class of collisions. We argue that beyond certain bounds for the deficiency/surplus angles no resolutions may be found that satisfy the imposed causality conditions.
Flat 3-Brane with Tension in Cascading Gravity
de Rham, Claudia; Tolley, Andrew J
2009-01-01
In the Cascading Gravity brane-world scenario, our 3-brane lies within a succession of lower-codimension branes, each with their own induced gravity term, embedded into each other in a higher-dimensional space-time. In the 6+1-dimensional version of this scenario, we show that a 3-brane with tension remains flat, at least for sufficiently small tension that the weak-field approximation is valid. The bulk solution is nowhere singular and remains in the perturbative regime everywhere.
THE STANDARD MILLING TIME OF FLAT SURFACES WITHOUT OUTLINE RESTRICTIONS
Leszek Skoczylas
2016-09-01
Full Text Available Knowing the standard operating times of technological operations is essential element in the business operations of every production enterprise. It is the basis for establishing the production capacity, planning the production schedule, or even calculating costs. The article presents a variety of methods used in the calculation of standard worktime of technological operations. An especially important distinction was made between calculating the total machining time and the actual cutting time. Through the examination of various machined flat surfaces, the results of worktime calculations from CATIA and the authored mathematical model are presented.
A new artificial material approach for flat THz frequency lenses
Savini, Giorgio; Zhang, Jin; 10.1364/OE.20.025766
2012-01-01
Stacked layers of metal meshes embedded in a dielectric substrate are routinely used for providing spectral selection at THz frequencies. Recent work has shown that particular geometries allow the refractive index to be tuned to produce practical artificial materials. Here we show that by spatially grading in the plane of the mesh we can manufacture a Graded Index (GrIn) thin flat lens optimized for use at THz frequencies. Measurements on a prototype lens show we are able to obtain the parabolic profile of a Woods type lens which is dependent only on the mesh parameters. This technique could realize other exotic optical devices.
Deep resistivity structure of Yucca Flat, Nevada Test Site, Nevada
Asch, Theodore H.; Rodriguez, Brian D.; Sampson, Jay A.; Wallin, Erin L.; Williams, Jackie M.
2006-01-01
The Department of Energy (DOE) and the National Nuclear Security Administration (NNSA) at their Nevada Site Office are addressing groundwater contamination resulting from historical underground nuclear testing through the Environmental Management program and, in particular, the Underground Test Area project. One issue of concern is the nature of the somewhat poorly constrained pre Tertiary geology and its effects on ground-water flow in the area adjacent to a nuclear test. Ground water modelers would like to know more about the hydrostratigraphy and geologic structure to support a hydrostratigraphic framework model that is under development for the Yucca Flat Corrective Action Unit (CAU). During 2003, the U.S. Geological Survey, supported by the DOE and NNSA-NSO, collected and processed data from 51 magnetotelluric (MT) and audio-magnetotelluric (AMT) stations at the Nevada Test Site in and near Yucca Flat to assist in characterizing the pre-Tertiary geology in that area. The primary purpose was to refine the character, thickness, and lateral extent of pre Tertiary confining units. In particular, a major goal has been to define the upper clastic confining unit (late Devonian - Mississippian-age siliciclastic rocks assigned to the Eleana Formation and Chainman Shale) in the Yucca Flat area. The MT and AMT data have been released in separate USGS Open File Reports. The Nevada Test Site magnetotelluric data interpretation presented in this report includes the results of detailed two-dimensional (2 D) resistivity modeling for each profile (including alternative interpretations) and gross inferences on the three dimensional (3 D) character of the geology beneath each station. The character, thickness, and lateral extent of the Chainman Shale and Eleana Formation that comprise the Upper Clastic Confining Unit are generally well determined in the upper 5 km. Inferences can be made regarding the presence of the Lower Clastic Confining Unit at depths below 5 km. Large fault
Modification of averaging process in GR: Case study flat LTB
Khosravi, Shahram; Mansouri, Reza
2007-01-01
We study the volume averaging of inhomogeneous metrics within GR and discuss its shortcomings such as gauge dependence, singular behavior as a result of caustics, and causality violations. To remedy these shortcomings, we suggest some modifications to this method. As a case study we focus on the inhomogeneous model of structured FRW based on a flat LTB metric. The effect of averaging is then studied in terms of an effective backreaction fluid. This backreaction fluid turns out to behave like a dark matter component, instead of dark energy as claimed in literature.
Unsteady Reversed Stagnation-Point Flow over a Flat Plate
Sin, Vai Kuong; Chio, Chon Kit
2012-01-01
This paper investigates the nature of the development of two-dimensional laminar flow of an incompressible fluid at the reversed stagnation-point. ". In this study, we revisit the problem of reversed stagnation-point flow over a flat plate. Proudman and Johnson (1962) first studied the flow and obtained an asymptotic solution by neglecting the viscous terms. This is no true in neglecting the viscous terms within the total flow field. In particular it is pointed out that for a plate impulsivel...
Unsteady Reversed Stagnation-Point Flow over a Flat Plate
Sin, Vai Kuong
2013-01-01
This paper investigates the nature of the development of two-dimensional laminar flow of an incompressible fluid at the reversed stagnation-point. ". In this study, we revisit the problem of reversed stagnation-point flow over a flat plate. Proudman and Johnson (1962) first studied the flow and obtained an asymptotic solution by neglecting the viscous terms. This is no true in neglecting the viscous terms within the total flow field. In particular it is pointed out that for a plate impulsively accelerated from rest to a constant velocity V0 that a similarity solution to the self-similar ODE is obtained which is noteworthy completely analytical.
Discrete flat-band solitons in the Kagome lattice
Vicencio, Rodrigo A
2013-01-01
We consider a model for a two-dimensional Kagome-lattice with defocusing nonlinearity, and show that families of localized discrete solitons may bifurcate from localized linear modes of the flat band with zero power threshold. Such fundamental nonlinear modes exist for arbitrarily strong nonlinearity, and correspond to unique configurations in the limit of zero inter-site coupling. We analyze their linear stability, and show that by choosing dynamical perturbations close to soft internal modes, a switching between solitons of different families may be obtained. In a window of small values of norm, a symmetry-broken localized state is found as the lowest-energy state.
Ultra flat supercontinuum generation in silicate dual core microstructured fiber
Buczynski, R.; Pysz, D.; Martynkien, T.; Lorenc, D.; Kujawa, I.; Nasilowski, T.; Berghmans, F.; Thienpont, H.; Stepien, R.
2009-08-01
In this paper we report on ultra flat supercontinuum generation in dual core photonic crystal fiber pumped in the normal dispersion regime. The fiber cladding is fabricated from custom NC21 borosilicate glass while the fiber cores is made of commercially available F2 high index lead-silicate glass from Schott Corp. We investigated the supercontinuum characteristics for single and double core excitation by a Ti:Sapphire oscillator delivering 100 fs pulses centered at 800 nm with an energy of 4.2 nJ. Dual core pumping resulted in appreciable flattening of the supercontinuum spectra in the range 875 - 950 nm.
High Performance Flat Plate Solar Thermal Collector Evaluation
Rockenbaugh, Caleb [National Renewable Energy Lab. (NREL), Golden, CO (United States); Dean, Jesse [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lovullo, David [National Renewable Energy Lab. (NREL), Golden, CO (United States); Lisell, Lars [National Renewable Energy Lab. (NREL), Golden, CO (United States); Barker, Greg [National Renewable Energy Lab. (NREL), Golden, CO (United States); Hanckock, Ed [National Renewable Energy Lab. (NREL), Golden, CO (United States); Norton, Paul [National Renewable Energy Lab. (NREL), Golden, CO (United States)
2016-09-01
This report was prepared for the General Services Administration by the National Renewable Energy Laboratory. The Honeycomb Solar Thermal Collector (HSTC) is a flat plate solar thermal collector that shows promising high efficiencies over a wide range of climate zones. The technical objectives of this study are to: 1) verify collector performance, 2) compare that performance to other market-available collectors, 3) verify overheat protection, and 4) analyze the economic performance of the HSTC both at the demonstration sites and across a matrix of climate zones and utility markets.
Calculating the Solar Energy of a Flat Plate Collector
Ariane Rosario
2014-09-01
Full Text Available The amount of solar energy that could be obtained by a flat plate solar collector of one square meter dimension is calculated in three different locations: Tampa FL, Fairbanks AL, and Pontianak Indonesia, considering the varying sunset time for each day of the year. The results show that if the collectors are placed near the equator, more total energy could be obtained. In fact, by placing a solar collector in Pontianak, Indonesia 12.42% more solar energy can be obtained than by placing it in Tampa and 96.9% more solar energy than Alaska.
Thermodynamics of flat FLRW universe in Rastall Theory
Moradpour, H
2016-01-01
In this paper, bearing the Clausius relation in mind, by using Friedman equations in Rastall theory and the Cai-Kim temperature we get a relation for the entropy of apparent horizon of a flat FLRW universe. In addition, we impose the entropy positivity condition on the obtained relation for the horizon entropy to find some constraints on the Rastall parameters. Moreover, we investigate the second and generalized second laws of thermodynamics. The results of considering a dominated prefect fluid with constant state parameter are also addressed which help us to be more familiar with Rastall cosmology and also to get more constraints on the Rastall parameters.
AXAF Alignment Test System Autocollimating Flat Error Correction
Lewis, Timothy S.
1995-01-01
The alignment test system for the advanced x ray astrophysics facility (AXAF) high-resolution mirror assembly (HRMA) determines the misalignment of the HRMA by measuring the displacement of a beam of light reflected by the HRMA mirrors and an autocollimating flat (ACF). This report shows how to calibrate the system to compensate for errors introduced by the ACF, using measurements taken with the ACF in different positions. It also shows what information can be obtained from alignment test data regarding errors in the shapes of the HRMA mirrors. Simulated results based on measured ACF surface data are presented.
Emittance Compensation in a Flat Beam RF Photoinjector
Rosenzweig, J. B.; Anderson, S.; Colby, E.; Serafini, L.
1997-05-01
The beam dynamics of a flat beam rf photoinjector, which is intended to produce asymmetric emittances for linear collider applications, are analyzed, by both analytical and computational methods. The analytical model is a generalization of the recently developed theory of emittance compensation in round beams(L.Serafini, and J.B. Rosenzweig, submitted to Physical Review E.), in which a new mode of laminar flow beam dynamics, the invariant envelope, is found to give the ideal conditions for emittance minimization. Three-dimensional rf and beam dynamics simulations are used to iluminate the analytical results. abstract.
An Incursion on Punching of Reinforced Concrete Flat Slabs
Dan-Vasile Bompa
2009-01-01
Full Text Available Starting from the early 60s continuous studies have been made regarding punching of concrete flat slabs. The evolution of technology and calculus systems influenced this engineering branch. Nowadays is possible to account in structural analysis all the non-linear behaviour of reinforced and prestressed concrete and to get the most close structural response in comparison with the real behaviour. As a controversy matter, several tests and theories have been developed. Nowadays researchers try to find the most accurate and economic formula for punching. This paper purpose is to make a survey on punching classical model and related nonlinear concrete behaviour regarded to this issue.
Scalar field collapse in a conformally flat spacetime
Chakrabarti, Soumya; Banerjee, Narayan [Indian Institute of Science Education and Research, Kolkata, Department of Physical Sciences, Mohanpur, West Bengal (India)
2017-03-15
The collapse scenario of a scalar field along with a perfect fluid distribution was investigated for a conformally flat spacetime. The theorem for the integrability of an anharmonic oscillator has been utilized. For a pure power-law potential of the form φ{sup n+1}, it was found that a central singularity is formed which is covered by an apparent horizon for n > 0 and n < -3. Some numerical results have also been presented for a combination of two different powers of φ in the potential. (orig.)
Turbo Detection in Rayleigh flat fading channel with unknown statistics
Paul Fortier
2010-11-01
Full Text Available The turbo detection of turbo coded symbols over correlated Rayleigh flat fading channels generatedaccording to Jakes’ model is considered in this paper. We propose a method to estimate the channelsignal-to-noise ratio (SNR and the maximum Doppler frequency. These statistics are required bythe linear minimum mean squared error (LMMSE channel estimator. To improve the system convergence,we redefine the channel reliability factor by taking into account the channel estimationerror statistics. Simulation results for rate 1=3 turbo code and two different normalized fading ratesshow that the use of the new reliability factor greatly improves the performance. The improvementis more substantial when channel statistics are unknown.
Quasistatic packings of droplets in flat microfluidic channels
Kadivar, Erfan
2016-02-01
As observed in recent experiments, monodisperse droplets self-assemble spontaneously in different ordered packings. In this work, we present a numerical study of the droplet packings in the flat rectangular microfluidic channels. Employing the boundary element method, we numerically solve the Stokes equation in two-dimension and investigate the appearance of droplet packing and transition between one and two-row packings of monodisperse emulsion droplets. By calculating packing force applied on the droplet interface, we investigate the effect of flow rate, droplet size, and surface tension on the packing configurations of droplets and transition between different topological packings.
On Levi-flat hypersurfaces with given boundary in Cn
Pierre DOLBEAULT
2008-01-01
Let S Cn be a compact connected 2-codimensional submanifold.If n ≥ 3,essentially local conditions and the assumption: every complex point of S is elliptic imply the existence of a projection in Cn of a Levi-flat (2n - 1)-subvariety whose boundary is S (Dolbeault,Tomassini,Zaitsev,2005).We extend the result when S is homeomorphic to a sphere and has one hyperbolic point.For n = 2 many results are known since the 1980's and a new result with a very technical hypothesis is announced.
Efficiencies of flat plate solar collectors at different flow rates
Chen, Ziqian; Furbo, Simon; Perers, Bengt;
2012-01-01
Two flat plate solar collectors for solar heating plants from Arcon Solvarme A/S are tested in a laboratory test facility for solar collectors at Technical University of Denmark (DTU). The collectors are designed in the same way. However, one collector is equipped with an ETFE foil between...... the absorber and the cover glass and the other is without ETFE foil. The efficiencies for the collectors are tested at different flow rates. On the basis of the measured efficiencies, the efficiencies for the collectors as functions of flow rate are obtained. The calculated efficiencies are in good agreement...
Thermodynamics of flat FLRW universe in Rastall theory
Moradpour, H., E-mail: h.moradpour@riaam.ac.ir
2016-06-10
In this paper, after referring to the Rastall theory, we address some of its cosmological consequences. Moreover, bearing the Clausius relation in mind, using Friedman equations in Rastall theory and the Cai–Kim temperature, we obtain a relation for the apparent horizon entropy of a flat FLRW universe. In addition, we impose the entropy positivity condition on the obtained relation for the horizon entropy, to find some constraints on the Rastall parameters. Moreover, we investigate the second and generalized second laws of thermodynamics. The results of considering a dominated prefect fluid of constant state parameter are also addressed helping us familiarize with the Rastall theory.
Deep Resistivity Structure of Yucca Flat, Nevada Test Site, Nevada.
Theodore H. Asch, Brian D. Rodriguez; Jay A. Sampson; Erin L. Wallin; and Jackie M. Williams.
2006-09-18
The Department of Energy (DOE) and the National Nuclear Security Administration (NNSA) at their Nevada Site Office are addressing groundwater contamination resulting from historical underground nuclear testing through the Environmental Management program and, in particular, the Underground Test Area project. One issue of concern is the nature of the somewhat poorly constrained pre Tertiary geology and its effects on ground-water flow in the area adjacent to a nuclear test. Ground water modelers would like to know more about the hydrostratigraphy and geologic structure to support a hydrostratigraphic framework model that is under development for the Yucca Flat Corrective Action Unit (CAU). During 2003, the U.S. Geological Survey, supported by the DOE and NNSA-NSO, collected and processed data from 51 magnetotelluric (MT) and audio-magnetotelluric (AMT) stations at the Nevada Test Site in and near Yucca Flat to assist in characterizing the pre-Tertiary geology in that area. The primary purpose was to refine the character, thickness, and lateral extent of pre Tertiary confining units. In particular, a major goal has been to define the upper clastic confining unit (late Devonian – Mississippian-age siliciclastic rocks assigned to the Eleana Formation and Chainman Shale) in the Yucca Flat area. The MT and AMT data have been released in separate USGS Open File Reports. The Nevada Test Site magnetotelluric data interpretation presented in this report includes the results of detailed two-dimensional (2 D) resistivity modeling for each profile (including alternative interpretations) and gross inferences on the three dimensional (3 D) character of the geology beneath each station. The character, thickness, and lateral extent of the Chainman Shale and Eleana Formation that comprise the Upper Clastic Confining Unit are generally well determined in the upper 5 km. Inferences can be made regarding the presence of the Lower Clastic Confining Unit at depths below 5 km. Large
Quasinormal frequencies of asymptotically flat two-dimensional black holes
Lopez-Ortega, A
2011-01-01
We discuss whether the minimally coupled massless Klein-Gordon and Dirac fields have well defined quasinormal modes in single horizon, asymptotically flat two-dimensional black holes. To get the result we solve the equations of motion in the massless limit and we also calculate the effective potentials of Schrodinger type equations. Furthermore we calculate exactly the quasinormal frequencies of the Dirac field propagating in the two-dimensional uncharged Witten black hole. We compare our results on its quasinormal frequencies with other already published.
Transient contact resistance in electrical connections with flat pins
Merlyan S. V.
2013-06-01
Full Text Available On the basis of experimental research, the authors have obtained dependences allowing to find promptly and with a small amount of calculations the optimum pressure value for elastic elements of flat contacts with different coatings (tin-bismuth, nickel, palladium, silver, gold, using the preset value of contact resistance Rпер. Moreover, the obtained results of estimation of quantity and stability of Rпер allow to choose the optimal coating according to the operating conditions of the contacts.
Milošević Miloš
2014-01-01
Full Text Available Liquidity risk management is a major activity of every bank. To be able to honor its matured liabilities, a bank strives to provide and maintain the required level of liquidity on a daily basis. Although each commercial bank has its own methodology of calculating the required liquidity level, in line with its adopted policies, the central bank has enacted the Decision on Liquidity Risk Management, prescribing the obligatory liquidity risk management policy.
Fast magnetic and electric dynamos in flat Klein bottle plasma flows
de Andrade, L C Garcia
2009-01-01
Recently Shukurov et al [Phys Rev \\textbf{E} (2008)] presented a numerical solution of a Moebius strip dynamo flow, to investigate its use in modelling dynamo flows in Perm torus of liquid sodium dynamo experiments. Here, by analogy one presents an electric dynamo on a twisted torus or Klein bottle topology. An exact solution in the form of flat Klein bottle dynamo flow is obtained. It is shown that even in the absence of magnetic dynamos initial electric fields can be amplified in distinct points of the Klein bottle. In this case diffusion is taken as ${\\eta}\\approx{5.0{\\times}10^{-3}{\\Omega}-m}$ the electric potential is obtained. The difference of electric fields at the beginning of plasma flow profile is ${\\Delta}E_{Dyn}\\approx{468\\frac{V}{m}}$, which is stronger than the electric dynamo field obtained in the magnetic axis of spheromaks, which is of the order of $E_{Dyn}\\approx{200\\frac{V}{m}}$. The potential of the dynamo at the surface of the Earth computed by Boozer [Phys Fluids \\textbf{B} (1993)] of $...
Local heat transfer measurements on a rotating flat blade model with a single film hole
Guoqiang Xu; Bin Yang; Zhi Tao; Zhenming Zhao; Hongwei Wu
2009-01-01
An experimental study was performed to measure the heat transfer coefficient distributions on a flat blade model under rotating oper-ating conditions.A steady-state thermochromic liquid crystal technique was employed to measure the surface temperature,and all the signals from the rotating reference frame were collected by the telemetering instrument via a wireless connection.Both air and CO2 were used as coolant. Results show that the rotational effect has a significant influence on the heat transfer coefficient distributions.The pro-files of hg/ho,which is the ratio of heat transfer coefficient with film cooling to that without film cooling,deflect towards the high-radius locations on both the pressure surface and suction surface as the rotation number(Rt)increases,and the deflective tendency is more evident on the suction surface.The variations in mainstream Reynolds number(ReD)and blowing ratio(M)present different distribu-tions of hg/ho on the pressure and suction surfaces,respectively.Furthermore,the coolant used for CO2 injection is prone to result in lower heat transfer coefficients.
Crust behavior in simultaneous melting and freezing on a submerged flat plate
Ganguli, A.; Bankoff, S.G.
1978-12-01
A theoretical and experimental investigation of the solidification of a flowing liquid onto a melting wall was carried out. In particular, the experimental work involved open channel laminar flow of water over a flat plate of n-decane. The point of interest is the dynamic behavior of the solidified crust, which forms a leading edge by melting. The motion of this leading edge was determined as a function of the water temperature, velocity, decane temperature and outlet weir height. This melting rate was found to be very sensitive to the water temperature and less dependent upon the other parameters. An approximate numerical method, using polynomial temperature profiles with time dependent coefficients, was used to solve the one-dimensional heat conduction model. From this, the dynamic behavior of the crust was predicted as a function of the experimental parameters and the local heat transfer coefficient on the freezing surface, which was later estimated. There is reasonable agreement between the predicted and experimentally observed motions of the leading edge.
An Output Channel Nonuniformity Compensation Driving Method in Flat Panel Display Driving Circuits
Kim, Jin-Ho; Ahn, Soon-Sung; Kwon, Christine H.; Kim, Seon-Yung; Lee, Jae-Sic; Choi, Byong-Deok
2006-12-01
Modern flat panel displays, including thin-film transistor liquid crystal displays (TFT-LCDs) and organic light-emitting diodes (OLEDs), pursue more and more natural color expression. This requires the data driving system should produce very fine and accurate signal voltages or currents. Especially, the uniformity among channels of a driving system is critically important because the color or luminance differences among columns are easily noticeable. We propose a simple and efficient driving method for solving the artifacts caused by the existing nonuniformity among channels of a driving system, and confirms its impact by simulations using C-programming. The nonuniformity among channels mostly stem from the random offset of the output circuits of a driving system, which in turn is caused by the process variations. The proposed driving method shares N-output circuits between N-output channels such that the existing offsets of the channels are averaged out. Thus, the output signal error due to the offsets spreads out among the channels, improving the uniformity between the channels.
Scheduling Coordinator’s Flat Rate Service for Wind Energy Development in Poland
Zbigniew Prondziński
2014-06-01
Full Text Available The development of the electricity market has made the energy industry an attractive investment for many businesses. In recent years, the electricity market has been going through the process of liberalization, which has contributed to the provision of new services for investors interested in the development of the energy industry. Recently, one of the most rapidly growing sources of electricity has been wind farms. Few investors are aware of the consequences of connecting wind farms to the national power grid, as well as of the subsequent exploitation of these resources. After the Electricity Sales Contract has been concluded, investors agree to predict electrical capacity generation within the span of 24 hours with a daily advance. The specific nature of wind farm functioning makes the prediction of electrical capacity generation difficult and, consequently, the owners bear the costs of deviations on the electricity balancing market. The resulting costs may result in the lack of liquidity of the project owner and, ultimately, in bankruptcy. In such a case, the Scheduling Coordinator’s flat rate service is a solution for the owner of a wind farm. The paper presents an analysis of selected forecasting models used to predict the electrical capacity of wind farms, as well as the Scheduling Coordinator’s service.
Contact angle dynamics in droplet impact on flat surfaces: Effect of surface wettability
Bayer, Ilker
2005-11-01
Contact angle dynamics is examined experimentally during spreading/recoiling of mm-sized water droplets impacting orthogonally on various flat surfaces with We = O(0.1)-O(10), Ca = O(0.001)- O(0.01), Oh = O(0.001) and Bo = O(0.1). In this impact regime, inertial, viscous, and capillary phenomena act in unison to influence contact angle dynamics. The wetting properties of the target surfaces range from wettable to non-wettable. The objective of the work is to provide insight into the dynamic behavior of the apparent (macroscopic) contact angle θ and its dependence on contact line velocity VCL at various degrees of surface wetting for droplets impacting with low to moderate Weber numbers. The hydrodynamic wetting theory of Cox (1998) is implemented to relate the microscopic wetting parameters to the observed θ vs. VCL data. It is concluded that Cox's model works well in the fast spreading regime, but proves inadequate for slow spreading where solid/liquid interactions are dominant. In addition, the molecular-kinetic theory of wetting by Blake and Haynes (1969) is tested with good results. This study offers guidance for numerical or analytical studies, which require special attention to the boundary conditions at the contact line, and more specifically the functional dependence of contact angle on contact line speed.
Ogawa, Y; Kosugi, N; Iwasa, H; Furusaka, M; Watanabe, N
1999-01-01
In order to obtain higher cold neutron intensity from a coupled liquid-hydrogen moderator with a premoderator for pulsed cold neutron sources, we examined a partial enhancement method, namely, narrow beam extraction for both a flat liquid-hydrogen moderator and a single-groove one. Combined with the narrow beam extraction, which is especially suitable for small-angle scattering and neutron reflectometry experiments, a single-groove moderator provides higher intensity, by about 30%, than a flat-surface moderator at the region of interest on a viewed surface. The effect of double-side beam extraction from such moderators on the intensity gain factor is also discussed. (author)
Influence of wire-coil inserts on the thermo-hydraulic performance of a flat-plate solar collector
Herrero Martín, R.; García, A.; Pérez-García, J.
2012-11-01
Enhancement techniques can be applied to flat-plate liquid solar collectors towards more compact and efficient designs. For the typical operating mass flow rates in flat-plate solar collectors, the most suitable technique is inserted devices. Based on previous studies from the authors, wire coils were selected for enhancing heat transfer. This type of inserted device provides better results in laminar, transitional and low turbulence fluid flow regimes. To test the enhanced solar collector and compare with a standard one, an experimental side-by-side solar collector test bed was designed and constructed. The testing set up was fully designed following the requirements of EN12975-2 and allow us to accomplish performance tests under the same operating conditions (mass flow rate, inlet fluid temperature and weather conditions). This work presents the thermal efficiency curves of a commercial and an enhanced solar collector, for the standardized mass flow rate per unit of absorber area of 0.02 kg/sm2 (in useful engineering units 144 kg/h for water as working fluid and 2 m2 flat-plate solar collector of absorber area). The enhanced collector was modified inserting spiral wire coils of dimensionless pitch p/D = 1 and wire-diameter e/D = 0.0717. The friction factor per tube has been computed from the overall pressure drop tests across the solar collectors. The thermal efficiency curves of both solar collectors, a standard and an enhanced collector, are presented. The enhanced solar collector increases the thermal efficiency by 15%. To account for the overall enhancement a modified performance evaluation criterion (R3m) is proposed. The maximum value encountered reaches 1.105 which represents an increase in useful power of 10.5% for the same pumping power consumption.
Dynamical mean-field theory for flat-band ferromagnetism
Nguyen, Hong-Son; Tran, Minh-Tien
2016-09-01
The magnetically ordered phase in the Hubbard model on the infinite-dimensional hyper-perovskite lattice is investigated within dynamical mean-field theory. It turns out for the infinite-dimensional hyper-perovskite lattice the self-consistent equations of dynamical mean-field theory are exactly solved, and this makes the Hubbard model exactly solvable. We find electron spins are aligned in the ferromagnetic or ferrimagnetic configuration at zero temperature and half filling of the edge-centered sites of the hyper-perovskite lattice. A ferromagnetic-ferrimagnetic phase transition driven by the energy level splitting is found and it occurs through a phase separation. The origin of ferromagnetism and ferrimagnetism arises from the band flatness and the virtual hybridization between macroscopically degenerate flat bands and dispersive ones. Based on the exact solution in the infinite-dimensional limit, a modified exact diagonalization as the impurity solver for dynamical mean-field theory on finite-dimensional perovskite lattices is also proposed and examined.
Innovative Ballasted Flat Roof Solar PV Racking System
Peek, Richard T. [Cascade Engineering, Grand Rapids, MI (United States)
2014-12-15
The objective of this project was to reduce the cost of racking for PV solar on flat commercial rooftops. Cost reductions would come from both labor savings and material savings related to the installation process. The rack would need to accommodate the majority of modules available on the market. Cascade Engineering has a long history of converting traditional metal type applications over to plastic. Injection molding of plastics have numerous advantages including selection of resin for the application, placing the material exactly where it is needed, designing in features that will speed up the installation process, and weight reduction of the array. A plastic rack would need to meet the requirements of UL2703, Mounting systems, mounting devices, clamping/retention devices, and ground lugs for use with flat-plate photovoltaic modules and panels. Comparing original data to the end of project racking design, racking material costs were reduced 50% and labor costs reduced 64%. The racking product accommodates all 60 and 72 cell panels on the market, meets UL2703 requirements, contributes only 1.3 pounds per square foot of weight to the array, requires little ballast to secure the array, automatically grounds the module when the module is secured, stacks/nests well for shipping/fewer lifts to the roof, provides integrated wire routing, allows water to drain on the roof, and accommodates various seismic roof connections. Project goals were achieved as noted in the original funding application.
EVN observations of low-luminosity flat-spectrum AGNs
Caccianiga, A; Thean, A; Dennett-Thorpe, J
2001-01-01
We present and discuss the results of VLBI (EVN) observations of three low-luminosity (P(5 GHz)<10^25 W/Hz) Broad Emission Line AGNs carefully selected from a sample of flat spectrum radio sources (CLASS). Based on the total and the extended radio power at 5 GHz and at 1.4 GHz respectively, these objects should be technically classified as radio-quiet AGN and thus the origin of their radio emission is not clearly understood. The VLBI observations presented in this paper have revealed compact radio cores which imply a lower limit on the brightness temperature of about 3X10^8 K. This result rules out a thermal origin for the radio emission and strongly suggests an emission mechanism similar to that observed in more powerful radio-loud AGNs. Since, by definition, the three objects show a flat (or inverted) radio spectrum between 1.4 GHz and 8.4 GHz, the observed radio emission could be relativistically beamed. Multi-epoch VLBI observations can confirm this possibility in two years time.
Interface fluctuations for deposition on enlarging flat substrates
Carrasco, I. S. S.; Takeuchi, K. A.; Ferreira, S. C.; Oliveira, T. J.
2014-12-01
We investigate solid-on-solid models that belong to the Kardar-Parisi-Zhang (KPZ) universality class on substrates that expand laterally at a constant rate by duplication of columns. Despite the null global curvature, we show that all investigated models have asymptotic height distributions and spatial covariances in agreement with those expected for the KPZ subclass for curved surfaces. In 1 + 1 dimensions, the height distribution and covariance are given by the GUE Tracy-Widom distribution and the Airy2 process instead of the GOE and Airy1 foreseen for flat interfaces. These results imply that when the KPZ class splits into curved and flat subclasses, as conventionally considered, the expanding substrate may play a role equivalent to, or perhaps more important than, the global curvature. Moreover, the translational invariance of the interfaces evolving on growing domains allowed us to accurately determine, in 2 + 1 dimensions, the analog of the GUE Tracy-Widom distribution for height distribution and that of the Airy2 process for spatial covariance. Temporal covariance is also calculated and shown to be universal in each dimension and in each of the two subclasses. A logarithmic correction associated with the duplication of columns is observed and theoretically elucidated. Finally, crossover between regimes with fixed-size and enlarging substrates is also investigated.
Pure and aerated water entry of a flat plate
Ma, Z. H.; Causon, D. M.; Qian, L.; Mingham, C. G.; Mai, T.; Greaves, D.; Raby, A.
2016-01-01
This paper presents an experimental and numerical investigation of the entry of a rigid square flat plate into pure and aerated water. Attention is focused on the measurement and calculation of the slamming loads on the plate. The experimental study was carried out in the ocean basin at Plymouth University's COAST laboratory. The present numerical approach extends a two-dimensional hydro-code to compute three-dimensional hydrodynamic impact problems. The impact loads on the structure computed by the numerical model compare well with laboratory measurements. It is revealed that the impact loading consists of distinctive features including (1) shock loading with a high pressure peak, (2) fluid expansion loading associated with very low sub-atmospheric pressure close to the saturated vapour pressure, and (3) less severe secondary reloading with super-atmospheric pressure. It is also disclosed that aeration introduced into water can effectively reduce local pressures and total forces on the flat plate. The peak impact loading on the plate can be reduced by half or even more with 1.6% aeration in water. At the same time, the lifespan of shock loading is prolonged by aeration, and the variation of impulse is less sensitive to the change of aeration than the peak loading.
Experiments to investigate lift production mechanisms on pitching flat plates
Stevens, P. R. R. J.; Babinsky, H.
2017-01-01
Pitching flat plates are a useful simplification of flapping wings, and their study can provide useful insights into unsteady force generation. Non-circulatory and circulatory lift producing mechanisms for low Reynolds number pitching flat plates are investigated. A series of experiments are designed to measure forces and study the unsteady flowfield development. Two pitch axis positions are investigated, namely a leading edge and a mid-chord pitch axis. A novel PIV approach using twin laser lightsheets is shown to be effective at acquiring full field of view velocity data when an opaque wing model is used. Leading-edge vortex (LEV) circulations are extracted from velocity field data, using a Lamb-Oseen vortex fitting algorithm. LEV and trailing-edge vortex positions are also extracted. It is shown that the circulation of the LEV, as determined from PIV data, approximately matches the general trend of an unmodified Wagner function for a leading edge pitch axis and a modified Wagner function for a mid-chord pitch axis. Comparison of experimentally measured lift correlates well with the prediction of a reduced-order model for a LE pitch axis.