These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Optimum Building Shapes for Energy Conservation  

ERIC Educational Resources Information Center

An approach to optimum building shape design is summarized that is based on local climate and is especially important for heat control in lower cost construction with temperature-responsive thermal characteristics. The study was supported by Istanbul Technical University. For journal availability see HE 508 931. (Author/LBH)

Berkoz, Esher Balkan

1977-01-01

2

Shape of cosmic string loops  

NASA Astrophysics Data System (ADS)

Complicated cosmic string loops will fragment until they reach simple, nonintersecting (“stable”) configurations. Through extensive numerical study we characterize these attractor loop shapes including their length, velocity, kink, and cusp distributions. We find that an initial loop containing M harmonic modes will, on average, split into 3M stable loops. These stable loops are approximately described by the degenerate kinky loop, which is planar and rectangular, independently of the number of modes on the initial loop. This is confirmed by an analytic construction of a stable family of perturbed degenerate kinky loops. The average stable loop is also found to have a 40% chance of containing a cusp. We examine the properties of stable loops of different lengths and find only slight variation. Finally we develop a new analytic scheme to explicitly solve the string constraint equations.

Copi, Craig J.; Vachaspati, Tanmay

2011-01-01

3

Optimum Cavity Radius Within a Bottle-Shaped Thermoacoustic Engine  

NASA Astrophysics Data System (ADS)

Heat energy can be used to generate acoustic energy due to thermoacoustic interactions. These engines can be used to create sound waves without any moving parts, like pistons, and could be used in space to convert solar energy into electricity. This research focused on the optimization of the geometry of bottle-shaped resonators used for thermoacoustic prime movers. These resonators have the advantage of non-harmonic overtones compared with half-wave resonators. The resonators for this research were constructed of concentric cylinders consisting of a neck piece and a cavity. The dimensions were approximately 5 cm with an ID of 2 cm for the neck and 10 cm long with IDs varying from about 2 cm to 12 cm for the cavity, producing operating frequencies ranging from approximately 1.2 to 1.5 kHz, following a theoretical model. Twelve different cavity radii were tested. The optimal cavity radius of 2.06 cm had an onset time that was 27 s faster and an onset temperature difference that was lower by 12 C than the smallest cavity (a half-wave resonator). Future research will explore the quality factor and optimum stack to surface area ratio of the engines.

Bridge, Justin; Andersen, Bonnie

2009-10-01

4

Size influence on shape of handwritten characters loops.  

PubMed

In the practice of forensic handwriting experts, the size of the writing on a questioned document may be different from that of known samples. In this study, the hypothesis of shape invariance of handwritten closed loops across size increasing was tested. A Fourier methodology was applied to 2325 small letters (591 a loops, 547 d loops, 596 o loops and 591 q loops) and 692 enlarged letters (162 a loops, 173 d loops, 173 o loops and 184 q loops), in a population of 13 writers who were asked to write letters in their usual size and about three times larger. Most of the writers presented similar modifications when increasing the size of the loops; they produced enlarged loops significantly more round and less slanted towards the right or the left. Furthermore, a discrimination was demonstrated between the writers on the basis of the enlarged loops, with a correct classification rate superior to 90%, whatever the letter (a, d, o or q). A classification of the enlarged loops in their corresponding writer was then possible. On the contrary, when comparing the enlarged loops to the small ones, almost one half of the enlarged loops were allocated to a wrong writer. Shape invariance was thus not supported for this particular application. Consequently, when comparing documents with a different writing size, differences in loops shape should be interpreted cautiously because they may be due to a different writer, but they may also be due to an enlargement of the loops. Therefore, reference material of similar writing size to that of the questioned writing should be requested for the comparison of handwritten loops. PMID:17207594

Marquis, R; Taroni, F; Bozza, S; Schmittbuhl, M

2007-10-01

5

Global optimum tree solution for single-source looped water distribution networks subjected to a single loading pattern  

NASA Astrophysics Data System (ADS)

A methodology, based on linear programming (LP) is developed for obtaining the global optimum tree solution for single-source looped water distribution networks (WDNs) subjected to a single loading pattern. Initially, a multiple-link loop is considered, and it is shown that the cost-discharge curve is concavoconvex: convex for local minima corresponding to trees and concave for discharges in between. The logic is then extended to P loop networks for which the cost-discharge surface is a (P+1)-dimensional hypersurface. A tree of the looped WDN is initially selected, optimized by LP, and successively modified, considering one loop at a time, so that the solution jumps on the hypersurface, from one local minimum to a better one. The procedure is continued until no further improvement in local optimum solution occurs; thus the final solution is the global optimum tree solution. The optimization procedure is illustrated through a one-source, 31-demand node, three-loop WDN, for which only 23 trees, out of possible 1048 trees, were required to be optimized for obtaining the global optimum tree solution. Since each link had to carry a minimum specified flow, one more iteration was carried out in the end to satisfy the minimum-flow constraint. Even though the tree solution is global optimum, the final solution satisfying the minimum-flow constraint cannot be claimed to be necessarily the global optimum.

Sonak, Vilas V.; Bhave, Pramod R.

1993-07-01

6

Measuring Shape-Dependent Looping Probability of DNA  

PubMed Central

Recently, several studies have shown that short doubled-stranded DNA (dsDNA) loops more readily than the wormlike chain model predicts. In most of these experiments, the intrinsic bendedness of dsDNA, which in theory can dramatically influence looping dynamics, was either avoided or unaccounted for. To investigate the effect of the shape of dsDNA on looping dynamics, we characterized the shapes of several synthetic dsDNA molecules of equal length but different sequences using gel electrophoresis. We then measured their looping rates using a FRET (Förster resonance energy transfer)-based assay and extracted the looping probability density known as the J factor (jM). We also used, for comparison, several dinucleotide angular parameter sets derived from the observed electrophoretic mobility to compute the jM predicted by the wormlike chain model. Although we found a strong correlation between curvature and jM, the measured jM was higher than most dinucleotide model predictions. This result suggests that it is difficult to reconcile the looping probability with the observed gel mobility within the wormlike chain model and underscores the importance of determining the intrinsic shape of dsDNA for proper theoretical analysis. PMID:23663850

Le, Tung T.; Kim, Harold D.

2013-01-01

7

Pattern drilling exploration: Optimum pattern types and hole spacings when searching for elliptical shaped targets  

Microsoft Academic Search

In this study the selection of the optimum type of drilling pattern to be used when exploring for elliptical shaped targets is examined. The rhombic pattern is optimal when the targets are known to have a preferred orientation. Situations can also be found where a rectangular pattern is as efficient as the rhombic pattern. A triangular or square drilling pattern

Lawrence J. Drew

1979-01-01

8

Optimal selection for sensor fault tolerant control of an EMS system via loop-shaping robust control  

Microsoft Academic Search

A systematic framework is presented for optimum sensor selection for control and fault tolerance subject to complex system requirements. The framework combines the well known robust control via loop-shaping design, the fault tolerance control concept and multiobjective optimisation. The framework is tested via realistic simulations on an Electro- Magnetic Suspension system which is a non-linear, unstable and safety-critical system with

Konstantinos Michail; Argyrios C Zolotas; Roger M Goodall; George Halikias

2011-01-01

9

H? loop shaping based robust power system stabilizer for dynamic equivalent multi-machine power system  

Microsoft Academic Search

This paper describes a method of designing H? loop shaping based robust power system stabilizer for a coherency based dynamic equivalent large power system. Group of coherent generators are identified on the basis of the equal acceleration. The dynamic equivalent parameters are determined by structure preservation of the coefficient matrices in a time-domain representation of the machines. H? loop shaping

R. Jayapal; J. K. Mendiratta

2010-01-01

10

NON-LINEAR FREQUENCY DOMAIN BASED OPTIMUM SHAPE DESIGN FOR UNSTEADY  

E-print Network

the unsteady effects that contribute to flutter, buffeting, poor gust and acoustic response, and dynamic stall) to the redesign of an oscillating airfoil in an inviscid transonic flow. The redesigned shape achieved a reduction

Jameson, Antony

11

Optimum forebody shaping for axisymmetric submersibles with turbulent boundary layers and BLO (Boundary Layer Control) afterbodies  

NASA Astrophysics Data System (ADS)

One objective of the Advanced Undersea Vehicle (AUV) program is to design a low drag vehicle. The approach in this investigation is boundary layer control by means of an annular suction slot located on the afterbody. Although wind tunnel data showed significant reduction in propulsive power over conventional shapes, an attempt was made to achieve further reduction by means of forebody shaping. Two methods were used to vary the geometric parameters for this analysis. The direct method, based on the mathematical development of the Series 58 bodies, allows the definition of a shape by a fifth-order polynomial based on the four fundamental parameters of fineness ratio, nose radius of curvature, location of maximum thickness, and prismatic coefficient. The inverse method allows various velocity distributions to define the body shape. The shapes derived by this method have flat velocity distributions and show similar trends to the polynomial shapes (about 3-percent reduction in propulsive power). The range of fineness ratios analyzed was from 1 to 10 at a volume-based Reynolds number of 3.2 million. In the range of 2.5 to 8, fineness ratio did not affect propulsive power more than 6 percent. A maximum improvement of 3 percent as shown by varying the meridian section.

Neumann, B. J.

1983-07-01

12

Gain-scheduling Control of Rotary Inverted Pendulum by Weight Optimization and H? Loop Shaping Procedure  

NASA Astrophysics Data System (ADS)

Gain-scheduling control is one of effective methods for plants whose dynamics changes significantly according to its operating point. A frozen parameter method is known to be a practical gain-scheduling controller synthesis, which interpolates the controllers designed at the prespecified (frozen) operating points according to the current operation point. Hyde et al. proposed a gain-scheduling control that H? loop shaping procedure is adopted as a controller synthesis at each operating point. H? loop shaping procedure is based on loop shaping of an open loop characteristic by frequency weights and is known to be effective for plants with bad condition number. However, weight selection satisfying control specifications is hard job for a designer. This paper describes the design of a suboptimal weight and a controller by means of algorithm that maximizes the robust stability margin and shapes the open loop characteristic into the desired shape at each operating point. Moreover, we formulate a weight optimization problem as a generalized eigenvalue minimization problem, which reduces the designer's burden of weight selection. Finally, we realize robust and high performance control system by scheduling both weights and controllers. The effectiveness of the proposed control system is verified in terms of the achieved robust stability margin and experimental time responses of a rotary inverted pendulum which involves strong nonlinear dynamics.

Yubai, Kazuhiro; Okuhara, Kazunori; Hirai, Junji

13

Optimum method of applying and removing a shaped-function signal for low-light-level image detection.  

PubMed

This paper presents an optimum method that exploits the principle of diffuse scattering and employs the least squares method (LSM) to apply and remove a shaped-function signal for low-light-level image detection. With the help of a sawtooth-shaped-function light signal applied to an image sensor, the LSM is employed to remove the sawtooth signal from the captured images and restore the weak image signal. The experiment process and result verify that this method can not only maintain the capability of upgrading the image sensor's sensitivity and signal-to-noise ratio like the previous method, but it also can improve the imaging speed in the low-light level, decrease the computation cost of the extraction process, and eliminate the influence of the environment light to satisfy the requirement of long-distance detection. PMID:24513744

Li, Gang; Zhao, Longfei; Zhou, Mei; Wang, Mengjun; Lin, Ling

2013-11-20

14

Optimum Structural Topology and Shape Design using Three Phase Hybrid GA and Artificial Density Method  

NASA Astrophysics Data System (ADS)

In this paper an efficient GA based Three Phase Topology Optimization algorithm which is an improvement over the Two-Phase Method developed by the team at IIT Delhi is presented. The Solid Isotropic Material with Penalization approach is outlined and Sequential Linear Programming method with move limits is utilized for solving the compliance minimization and volume minimization problems with volume and displacement constraints respectively. The need for parametric studies with various penalty factors and initial starting constraints are emphasized. The availability of accurate constraint derivatives with minimal effort is a boon but as in any NLP problem with a large number of variables, the global nature of the optimum is somewhat suspect in SIMP based method. A detailed comparison of the performances of the two phase and three phase methods and the SIMP method is presented for problems of different size and general conclusions are drawn.

Ramakrishnan, C. V.; Singh, Nidur; Sehgal, D. K.

2007-05-01

15

GA-based optimum design of a shape memory alloy device for seismic response mitigation  

Microsoft Academic Search

Damping systems discussed in this work are optimized so that a three-story steel frame structure and its shape memory alloy (SMA) bracing system minimize response metrics due to a custom-tailored earthquake excitation. Multiple-objective numerical optimization that simultaneously minimizes displacements and accelerations of the structure is carried out with a genetic algorithm (GA) in order to optimize SMA bracing elements within

O. E. Ozbulut; P. N. Roschke; P. Y Lin; C. H. Loh

2010-01-01

16

Optimum nanoparticles for electrocatalytic oxygen reduction: the size, shape and new design.  

PubMed

The electrocatalytic oxygen reduction reaction (ORR) on nanoparticles has attracted much attention in recent years for its significance in fuel cell applications. Here by combining density functional theory (DFT) calculations with the periodic continuum solvation model based on modified-Poisson-Boltzmann (CM-MPB) electrostatics, we analyzed the ORR activity on a set of differently sized Pt nanoparticles in order to identify the optimum particles for a better designed catalyst. We show that Pt nanoparticles of ?2 nm size have the highest ORR mass activity, which is attributed to the variation of the effective reaction sites on the exposed {111} facet at the electrochemical conditions. We propose a type of a new nanocatalyst for the electrocatalytic oxygen reduction based on the knowledge from large-scale first principles simulations on Pt nanoparticles. The new catalyst has inert metal Au as the frame for the Pt nanoparticle and exposed Pt{111} sites are the active site for oxygen reduction. Such an architecture can not only prevent the initial O corrosion at the edge sites but also significantly improve the activity. The theoretical work provides a promising new direction for the rational design of a stable and active ORR catalyst via nano-structure engineering. PMID:24077215

Wei, Guang-Feng; Liu, Zhi-Pan

2013-11-14

17

Synthesis and optimum luminescence of doughnut-shape undoped and doped CaMoO4.  

PubMed

In this work, we report the size and shape-controlled synthesis of CaMoO4 nanocrystals with an aim of investigate their structural, electronic, and luminescent properties. The samples were carefully characterized by X-ray diffraction, transmission electron microscopy, Fourier transformed infrared spectroscopy, UV-vis diffuse reflectance spectroscopy, and luminescence spectroscopy. It is found that when MoO4(2-) and Ca2+ were mixed at relatively low temperature (in ice salt bath), the reaction produces a uniform population of microparticles with an interesting "doughnut" shapes. Due to the low temperature, the process of crystal nucleus is slow enough to for separated growth. The intensity of the absorption band for CaMoO4 nanocrystals was greatly enhanced with the decrease reaction temperature. The as-prepared CaMoO4 doughnut phosphors reveal a broad emission with a maximum at 500 nm, which exhibit blue-green emission. We also study the luminescent property for Eu(3+)-doped CaMoO4. As for the Eu(3+)-doped samples (initial Ca2+:Eu3+ molar ratio 20:1), it is shown that Eu3+ was substituted at Ca2+ sites in the CaMoO4 host lattice, which favors energy transition between Eu3+ ions and molybdate groups that caused the decrease of strength of the peak in emission spectra. PMID:24734581

Lv, Li; Liu, Xiaoqing; Xu, Cong; Wang, Xiaojing

2014-05-01

18

Segmented shape memory alloy actuators using hysteresis loop control  

NASA Astrophysics Data System (ADS)

A new approach to the design and control of shape memory alloy (SMA) actuators is presented. SMA wires are divided into many segments and their thermal states are controlled individually as a group of finite state machines. Instead of driving a current to the entire SMA wire and controlling the wire length based on the analog strain-temperature characteristics, the new method controls the binary state (hot or cold) of individual segments and thereby the total displacement is proportional to the length of the heated segments, i.e. austenite phase. Although the thermomechanical properties of SMA are highly nonlinear and uncertain with a prominent hysteresis, segmented binary control is robust and stable, providing characteristics similar to a stepping motor. However, the heating and cooling of each segment to its bi-stable states entail longer time and larger energy for transition. In this paper, an efficient method for improving the speed of response and power consumption is developed by exploiting the inherent hysteresis of SMA. Instead of keeping the extreme temperatures continuously, the temperatures return to intermediate 'hold' temperatures closer to room temperature but sufficient to keep constant phase. Coordination of the multitude of segments having independent thermal states allows for faster response with little latency time even for thick SMA wires. Based on stress dependent thermomechanical characteristics, the hold temperature satisfying a given stress margin is obtained. The new control method is implemented using the Peltier effect thermoelectric devices for selective segment-by-segment heating and cooling. Experiments demonstrate the effectiveness of the proposed method.

Selden, Brian; Cho, Kyujin; Asada, H. Harry

2006-04-01

19

Shaping Power System Inter-area Oscillations through Control Loops of Grid Integrated Wind Farms  

E-print Network

Shaping Power System Inter-area Oscillations through Control Loops of Grid Integrated Wind Farms the inter-area oscillation spectrum of a large wind-integrated power system. The power system is modeled using a contin- uum representation of the electro-mechanical swing dynamics with the wind power entering

Gayme, Dennice

20

Shaping of Looped Miniaturized Chalcogenide Fiber Sensing Heads for Mid-Infrared Sensing  

PubMed Central

Chalcogenide glass fibers are promising photonic tools to develop Fiber Evanescent Wave Spectroscopy (FEWS) optical sensors working in the mid-infrared region. Numerous pioneering works have already been carried out showing their efficiency, especially for bio-medical applications. Nevertheless, this technology remains confined to academic studies at the laboratory scale because chalcogenide glass fibers are difficult to shape to produce reliable, sensitive and compact sensors. In this paper, a new method for designing and fabricating a compact and robust sensing head with a selenide glass fiber is described. Compact looped sensing heads with diameter equal to 2 mm were thus shaped. This represents an outstanding achievement considering the brittleness of such uncoated fibers. FEWS experiments were implemented using alcoholic solutions as target samples showing that the sensitivity is higher than with the routinely used classical fiber. It is also shown that the best compromise in term of sensitivity is to fabricate a sensing head including two full loops. From a mechanical point of view, the breaking loads of the loop shaped head are also much higher than with classical fiber. Finally, this achievement paves the way for the use of mid-infrared technology during in situ and even in vivo medical operations. Indeed, is is now possible to slide a chalcogenide glass fiber in the operating channel of a standard 2.8 mm diameter catheter. PMID:25264953

Houizot, Patrick; Anne, Marie-Laure; Boussard-Plédel, Catherine; Loréal, Olivier; Tariel, Hugues; Lucas, Jacques; Bureau, Bruno

2014-01-01

21

Shaping of looped miniaturized chalcogenide fiber sensing heads for mid-infrared sensing.  

PubMed

Chalcogenide glass fibers are promising photonic tools to develop Fiber Evanescent Wave Spectroscopy (FEWS) optical sensors working in the mid-infrared region. Numerous pioneering works have already been carried out showing their efficiency, especially for bio-medical applications. Nevertheless, this technology remains confined to academic studies at the laboratory scale because chalcogenide glass fibers are difficult to shape to produce reliable, sensitive and compact sensors. In this paper, a new method for designing and fabricating a compact and robust sensing head with a selenide glass fiber is described. Compact looped sensing heads with diameter equal to 2 mm were thus shaped. This represents an outstanding achievement considering the brittleness of such uncoated fibers. FEWS experiments were implemented using alcoholic solutions as target samples showing that the sensitivity is higher than with the routinely used classical fiber. It is also shown that the best compromise in term of sensitivity is to fabricate a sensing head including two full loops. From a mechanical point of view, the breaking loads of the loop shaped head are also much higher than with classical fiber. Finally, this achievement paves the way for the use of mid-infrared technology during in situ and even in vivo medical operations. Indeed, is is now possible to slide a chalcogenide glass fiber in the operating channel of a standard 2.8 mm diameter catheter. PMID:25264953

Houizot, Patrick; Anne, Marie-Laure; Boussard-Plédel, Catherine; Loréal, Olivier; Tariel, Hugues; Lucas, Jacques; Bureau, Bruno

2014-01-01

22

A Study on the Stress Analysis and Optimum Design of S-Shape Wheel for Rolling Stock  

NASA Astrophysics Data System (ADS)

The mechanical stress due to the wheel-rail contact and thermal stress due to the drag braking increase the incidence of wheel failure. So, firstly, stress analyses(mechanical, thermal and combined stress) of wheel plate are performed using 3-dimensional finite element method(FEM). Secondly, the optimum design of wheel plate is investigated in order to reduce weight of the wheel based on results of stress analysis. The optimum design is performed using 2-dimensional axisymmetric F.E. model and its results are verified by 3-dimensional F. E. analysis.

Sung, Ki Deug; Yun, Tae Hyeok; Lee, Geun Sun; Kim, Ki Hong

23

Optimum Shape Design for Unsteady Three-Dimensional Viscous Flows Using a Nonlinear Frequency-Domain Method  

E-print Network

and acoustic response, and dynamic stall. As yet, there have been few efforts in this direction. The demanding the continuous and discrete) to the redesign of an oscillating airfoil in an inviscid transonic flow. The redesigned shape ac

Jameson, Antony

24

Node-Wise Topological Shape Optimum Design for Structural Reinforced Modeling of Michell-Type Concrete Deep Beams  

NASA Astrophysics Data System (ADS)

This study presents an associated structural design to continuous material topology optimization and a particular case of shape optimization using node-wise densities as design parameters. The generation of optimal shapes and topologies represented in this study is based on a three-dimensional density function bilinearly interpolated by element shape functions and nodal densities. The material interface between void and solid regions is described by a specific 0.5 cut-off level of continuous and smooth iso-lines of the nodal density function on a fixed mesh. This approach allows us to perform a simultaneous node-wise topology and shape optimization, which can be easily implemented by existing gradient-based optimization codes. Contrary to those of conventional material topology optimization methods, these optimal solutions are similar to ideal optimal solutions from analytical optimization techniques. Numerical examples for structural reinforced modeling of Michell-type concrete deep beams are used to demonstrate the efficiency and superiority of the resolutions of the present method.

Lee, Dongkyu; Park, Sungsoo; Shin, Soomi

25

A study of optimum cowl shapes and flow port locations for minimum drag with effective engine cooling, volume 2  

NASA Technical Reports Server (NTRS)

The listings, user's instructions, sample inputs, and sample outputs of two computer programs which are especially useful in obtaining an approximate solution of the viscous flow over an arbitrary nonlifting three dimensional body are provided. The first program performs a potential flow solution by a well known panel method and readjusts this initial solution to account for the effects of the boundary layer displacement thickness, a nonuniform but unidirectional onset flow field, and the presence of air intakes and exhausts. The second program is effectually a geometry package which allows the user to change or refine the shape of a body to satisfy particular needs without a significant amount of human intervention. An effort to reduce the cruise drag of light aircraft through an analytical study of the contributions to the drag arising from the engine cowl shape and the foward fuselage area and also that resulting from the cooling air mass flowing through intake and exhaust sites on the nacelle is presented. The programs may be effectively used to determine the appropriate body modifications or flow port locations to reduce the cruise drag as well as to provide sufficient air flow for cooling the engine.

Fox, S. R.; Smetana, F. O.

1980-01-01

26

A study of optimum cowl shapes and flow port locations for minimum drag with effective engine cooling, volume 1  

NASA Technical Reports Server (NTRS)

The contributions to the cruise drag of light aircraft arising from the shape of the engine cowl and the forward fuselage area and also that resulting from the cooling air mass flow through intake and exhaust sites on the nacelle were analyzed. The methods employed for the calculation of the potential flow about an arbitrary three dimensional body are described with modifications to include the effects of boundary layer displacement thickness, a nonuniform onset flow field (such as that due to a rotating propeller), and the presence of air intakes and exhausts. A simple, reliable, largely automated scheme to better define or change the shape of a body is also presented. A technique was developed which can yield physically acceptable skin friction and pressure drag coefficients for isolated light aircraft bodies. For test cases on a blunt nose Cessna 182 fuselage, the technique predicted drag reductions as much as 28.5% by body recontouring and proper placements and sizing of the cooling air intakes and exhausts.

Fox, S. R.; Smetana, F. O.

1980-01-01

27

Loop shaped dicarboxylate-bridged dimolybdenum(ii) bisphosphine compounds - a rational synthesis.  

PubMed

The reaction of the tetrametallic molecular loop [(CH3CN)6Mo2(OOC-C4H6-COO)]2[BF4]4 () (1 equiv.) with 2 equiv. of bis(diphenylphosphino)amine (dppa), 1,2-bis(diphenylphosphino)ethane (dppe) and bis(diphenylphosphino)methane (dppm) in propionitrile leads to the formation of the still tetrametallic complexes [(CH3CH2CN)4(X)Mo2(OOC-C4H6-COO)]2[BF4]4 (X = dppa (), dppe (), dppm ()), also displaying a loop structure. All three complexes are characterized by NMR spectroscopy ((1)H, (11)B, (13)C{(1)H}, (19)F, (31)P{(1)H}), IR spectroscopy, elemental analysis, TG-MS measurements and UV-vis spectroscopy, compounds and additionally by X-ray single crystal diffraction. PMID:25187997

Höhne, Dominik; Herdtweck, Eberhardt; Pöthig, Alexander; Kühn, Fritz E

2014-09-30

28

Anomalous Ferroelectric Hysteresis Loops.  

National Technical Information Service (NTIS)

Materials that exhibit anomalous ferroelectric hysteresis loops appear throughout the literature. These loops have irregular shapes that diverge from the normal hysteresis loop which is characteristic of most ferroelectrics. The observation of a unique hy...

F. J. Murdoch

1971-01-01

29

Shapes  

NSDL National Science Digital Library

Welcome! Let\\'s explore the world of shapes. At Kids Online Resources (OLR) Learning is Fun, click on Shapes and see what types of everyday items are made of different simple shapes. Here is a game to play using shapes in patterns.Crack hacker's cafe If you want to make shapes into 3D forms, go to this site 2D to 3D morphing : flat 2D shapes rise up to make 3D forms and follow the directions. You may need a parent to ...

Fletcher, Ms.

2007-10-23

30

Control of a flexible link by shaping the closed loop frequency response function through optimised feedback filters  

NASA Astrophysics Data System (ADS)

A frequency domain method is presented to design a closed-loop control for vibration reduction flexible mechanisms. The procedure is developed on a single-link flexible arm, driven by one rotary degree of freedom servomotor, although the same technique may be applied to similar systems such as supports for aerospace antennae or solar panels. The method uses the structural frequency response functions (FRFs), thus avoiding system identification, that produces modeling uncertainties. Two closed-loops are implemented: the inner loop uses acceleration feedback with the aim of making the FRF similar to that of an equivalent rigid link; the outer loop feeds back displacements to achieve a fast positioning response and null steady state error. In both cases, the controller type is established a priori, while actual characteristics are defined by an optimisation procedure in which the relevant FRF is constrained into prescribed bounds and stability is taken into account.

Del Vescovo, D.; D'Ambrogio, W.

1995-01-01

31

Optimum Flapping Wing Motions of Dragonfly  

NASA Astrophysics Data System (ADS)

We studied the optimum flapping wing motions of a dragonfly (Anax parthenope julius) from hovering to cruising flight at various speeds, using a 3D Navier-Stokes code coupled with an optimization algorithm. The minimum necessary power curve and optimum flapping wing motions for the various flight velocities were determined using the optimization algorithm. The minimum power curve shows the typical U-shape. The optimum flapping wing motions were evaluated by comparison with experimental data. Examining the flow patterns showed that the large-scale flow separation around the wings is suppressed at these optimum conditions, except for very low flight speeds including hovering.

Kamisawa, Yuichi; Isogai, Koji

32

Robust Voltage Stabilization in an Isolated Wind-Diesel Power System using PSO based-Fixed Structure H? Loop Shaping Control  

NASA Astrophysics Data System (ADS)

It is well known that the power system controller designed by H? control is complicated, high order and impractical. In power system applications, practical structures such as proportional integral derivative (PID) etc., are widely used, because of their simple structure, less number of tuning parameters and low-order. However, tuning of controller parameters to achieve a good performance and robustness is based on designer's experiences. To overcome this problem, this paper proposes a fixed structure robust H? loop shaping control to design Static Var Compensator (SVC) and Automatic Voltage Regulator (AVR) for robust stabilization of voltage fluctuation in an isolated wind-diesel hybrid power system. The structure of the robust controller of SVC and AVR is specified by a PID controller. In the system modeling, a normalized coprime factorization is applied to represent possible unstructured uncertainties in the power system such as variation of system parameters, generating and loading conditions etc. Based on the H? loop shaping, the performance and robust stability conditions are formulated as the optimization problem. The particle swarm optimization is applied to solve for PID control parameters of SVC and AVR simultaneously. Simulation studies confirm the control effect and robustness of the proposed control.

Vachirasricirikul, Sitthidet; Ngamroo, Issarachai; Kaitwanidvilai, Somyot

33

Shapes, Shapes, Shapes!  

NSDL National Science Digital Library

Let\\'s practice identifying our shapes! Look at all the choices and find the one that can Match that Shape. Help Pauly! Drag and drop to Match the Shapes! Listen closely to what color we should Paint the Shapes. ...

Stringfield, Miss

2008-11-17

34

The Kissing-Loop T-Shaped Structure Translational Enhancer of Pea Enation Mosaic Virus Can Bind Simultaneously to Ribosomes and a 5? Proximal Hairpin  

PubMed Central

The Pea Enation Mosaic Virus (PEMV) 3? translational enhancer, known as the kissing-loop T-shaped structure (kl-TSS), binds to 40S subunits, 60S subunits, and 80S ribosomes, whereas the Turnip crinkle virus (TCV) TSS binds only to 60S subunits and 80S ribosomes. Using electrophoretic mobility gel shift assay (EMSA)-based competition assays, the kl-TSS was found to occupy a different site in the ribosome than the P-site-binding TCV TSS, suggesting that these two TSS employ different mechanisms for enhancing translation. The kl-TSS also engages in a stable, long-distance RNA-RNA kissing-loop interaction with a 12-bp 5?-coding-region hairpin that does not alter the structure of the kl-TSS as revealed by molecular dynamics simulations. Addition of the kl-TSS in trans to a luciferase reporter construct containing either wild-type or mutant 5? and 3? PEMV sequences suppressed translation, suggesting that the kl-TSS is required in cis to function, and both ribosome-binding and RNA interaction activities of the kl-TSS contributed to translational inhibition. Addition of the kl-TSS was more detrimental for translation than an adjacent eIF4E-binding 3? translational enhancer known as the PTE, suggesting that the PTE may support the ribosome-binding function of the kl-TSS. Results of in-line RNA structure probing, ribosome filter binding, and high-throughput selective 2?-hydroxyl acylation analyzed by primer extension (hSHAPE) of rRNAs within bound ribosomes suggest that kl-TSS binding to ribosomes and binding to the 5? hairpin are compatible activities. These results suggest a model whereby posttermination ribosomes/ribosomal subunits bind to the kl-TSS and are delivered to the 5? end of the genome via the associated RNA-RNA interaction, which enhances the rate of translation reinitiation. PMID:23986599

Gao, Feng; Gulay, Suna P.; Kasprzak, Wojciech; Dinman, Jonathan D.

2013-01-01

35

Shapes, shapes, shapes!  

NSDL National Science Digital Library

Shapes are awesome! Can you Assemble the Square? Play this game and find out! Slide, flip, and rotate the shapes in RoboPacker! Practice your geometry vocabulary and use the Flash Cards for Geometry!! ...

Johnson, Ms.

2008-04-30

36

Loop shaping of structural dynamics  

E-print Network

Dynamic response of a stature can be characterized by mass, stiffness, and damping. Design of a conventional structure is primarily based on stiffness characteristics because damping is assumed to be negligible. Although stiffness-based design...

Kim, Byeong Hwa

2012-06-07

37

EXTREME-ULTRAVIOLET MULTI-WAVELENGTH OBSERVATIONS OF QUASI-PERIODIC PULSATIONS IN A SOLAR POST-FLARE CUSP-SHAPE LOOP WITH SDO/AIA  

SciTech Connect

We present extreme-ultraviolet multi-wavelength observations with the SDO/AIA instruments of quasi-periodic pulsations (QPPs) propagating along a cusp-shaped loop formed after an M2.2 flare on the Sun. Our motivation is to detect whether there were slow-mode magnetoacoustic waves propagating along its protruding flux tube. To this end, with fast Fourier transform we extract the short (<3 minutes) and long (>3 minutes) period components of the QPPs from time-space diagrams of the tube slices. We find that velocity differences did exist among the short/long-period components of different wavelengths, but only one event in the long-period ones showed they were greater than the measurement errors (e.g., 65 km s{sup -1}), which were 330 km s{sup -1} detected in 171 A, 590 km s{sup -1} in 211 A, and 180 km s{sup -1} in 304 A. The intensity modulation in all wavelengths is found to be very large, e.g., {approx}60% of the emission trend for an event in the 171 A passband, which would be an order of magnitude higher than the perturbation of the plasma density in the slow-mode magnetoacoustic waves. Moreover, only the QPPs with upward velocities of 50-300 km s{sup -1} are found in the tube, and the downward ones of several tens of kilometers are never unambiguously detected. Therefore, most of the QPP events under study were likely the episodic outflows along the tube, and the one with a supersonic speed of 590 km s{sup -1} may be a kink wave.

Su, J. T. [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Science, Beijing 100012 (China); Shen, Y. D.; Liu, Y. [National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, Kunming 650011 (China)

2012-07-20

38

Using Signal Detection Theory and Time Window-based Human-In-The-Loop simulation as a tool for assessing the effectiveness of different qualitative shapes in continuous monitoring tasks.  

PubMed

This paper provides a case study of Signal Detection Theory (SDT) as applied to a continuous monitoring dual-task environment. Specifically, SDT was used to evaluate the independent contributions of sensitivity and bias to different qualitative gauges used in process control. To assess detection performance in monitoring the gauges, we developed a Time Window-based Human-In-The-Loop (TWHITL) simulation bed. Through this test bed, we were able to generate a display similar to those monitored by console operators in oil and gas refinery plants. By using SDT and TWHITL, we evaluated the sensitivity, operator bias, and response time of flow, level, pressure, and temperature gauge shapes developed by Abnormal Situation Management(®) (ASM(®)) Consortium (www.asmconsortium.org). Our findings suggest that display density influences the effectiveness of participants in detecting abnormal shapes. Furthermore, results suggest that some shapes elicit better detection performance than others. PMID:24079651

Kim, Jung Hyup; Rothrock, Ling; Laberge, Jason

2014-05-01

39

OPTIMUM PLASMA STATES FOR NEXT STEP TOKAMAKS  

SciTech Connect

OAK A271 OPTIMUM PLASMA STATES FOR NEXT STEP TOKAMAKS. The dependence of the ideal ballooning {beta} limit on aspect ratio, A, and elongation {kappa} is systematically explored for nearly 100% bootstrap current driven tokamak equilibria in a wide range of the shape parameters (A = 1.2-7.0, {kappa} = 1.5-6.0 with triangularity {delta} = 0.5). The critical {beta}{sub N} is shown to be optimal at {kappa} = 3.0-4.0 for all A studied and increases as A decreases with a dependence close to A{sup -0.5}. The results obtained can be used as a theoretical basis for the choice of optimum aspect ratio and elongation of next step burning plasma tokamaks or tokamak reactors.

LIN-LIU,YR; STAMBAUGH,RD

2002-11-01

40

Optimum Designs in Regression Problems  

Microsoft Academic Search

Although regression problems have been considered by workers in all sciences for many years, until recently relatively little attention has been paid to the optimum design of experiments in such problems. At what values of the independent variable should one take observations, and in what proportions? The purpose of this paper is to develop useful computational procedures for finding optimum

J. Kiefer; J. Wolfowitz

1959-01-01

41

Optimum placement of piezoelectric ceramic modules for vibration suppression of highly constrained structures  

NASA Astrophysics Data System (ADS)

The vibration suppression efficiency of so-called shunted piezoelectric systems is decisively influenced by the number, shape, dimensions and position of the piezoelectric ceramic elements integrated into the structure. This paper presents a procedure based on evolutionary algorithms for optimum placement of piezoelectric ceramic modules on highly constrained lightweight structures. The optimization loop includes the CAD software CATIA V5, the FE package ANSYS and DynOPS, a proprietary software tool able to connect the Evolving Object library with any simulation software that can be started in batch mode. A user-defined piezoelectric shell element is integrated into ANSYS 9.0. The generalized electromechanical coupling coefficient is used as the optimization objective. Position, dimensions, orientation, embedding location in the composite lay-up and wiring of customized patches are determined for optimum vibration suppression under consideration of operational and manufacturing constraints, such as added mass, maximum strain and requirements on the control circuit. A rear wing of a racing car is investigated as the test object for complex, highly constrained geometries.

Belloli, Alberto; Ermanni, Paolo

2007-10-01

42

Towards optimum demodulation of bandwidth-limited and low SNR square-wave subcarrier signals  

NASA Technical Reports Server (NTRS)

The optimum phase detector is presented for tracking square-wave subcarriers that have been bandwidth limited to a finite number of harmonics. The phase detector is optimum in the sense that the loop signal-to-noise ratio (SNR) is maximized and, hence, the rms phase tracking error is minimized. The optimum phase detector is easy to implement and achieves substantial improvement. Also presented are the optimum weights to combine the signals demodulated from each of the harmonics. The optimum weighting provides SNR improvement of 0.1 to 0.15 dB when the subcarrier loop SNR is low (15 dB) and the number of harmonics is high (8 to 16).

Feria, Y.; Hurd, W.

1995-01-01

43

Sigmoid-to-Flux-Rope Transition Leading to A Loop-Like Coronal Mass Ejection  

E-print Network

of a GOES-class C3.2 flare, as the S-shaped loop speeds up its trans- formation into an arch-shaped loop special scrutiny are sigmoids (Rust & Kumar 1996), which are forward or inverse S-shaped coronal loops is usually followed by the formation of unsheared arcades or cusped loops, a process termed "sigmoid

44

Optimum optical limited scan antenna  

NASA Astrophysics Data System (ADS)

An optical limited scan antenna system is considered for applications such as spot coverage of a small portion of the earth from a satellite. The optimum criterion relating aperture efficiency, number of control elements, and angular coverage is revisited briefly. The optical scheme advocated utilizes a bootlace aperture lens, a generalized Luneberg lens focused to the near field, and a small array of active elements. The operation of the system is described first in terms of geometrical optics and elementary diffraction principles. Numerical computations for a case of practical interest verify the expectation of near optimum performance.

Dufort, E. C.

1986-09-01

45

OPTIMUM FREQUENCY OF CALIBRATION MONITORING  

EPA Science Inventory

The paper develops an algorithm by which to compute the optimal frequency of calibration monitoring to minimize the total cost of analyzing a set of samples and the required calibration standards. Optimum calibration monitoring is needed because of the high cost and calibration d...

46

The optimum quantity of debt  

Microsoft Academic Search

We find that the welfare gains to being at the optimum quantity of debt rather than the current US level are small, and, therefore, concerns regarding the high level of debt in the US economy may be misplaced. This finding is based on a model of a large number of infinitely lived households whose saving behavior is influenced by precautionary

S. Rao Aiyagari; Ellen R. McGrattan

1998-01-01

47

Phasing Loops  

E-print Network

This work consists of a set of eight vector graphics animations exploring phasing loops, intended to be displayed on televisions and monitors, for home use or exhibition in art galleries as Generative Cinema installations. By combining animated...

Guinski, Rodrigo 1980-

2012-11-30

48

Protein folding and loop closure: Some bioinformatics challenges  

NASA Astrophysics Data System (ADS)

Protein loop closure is a fundamental concept in protein design and structure prediction. In this paper, we show how loops play a role in shaping a protein into its native three-dimensional structure. Hence, an understanding of the protein movement at a molecular biology level is essential prior to developing practical solutions for closing loops.

Lau, N.; Oxley, A.; Nayan, M. Y.

2012-09-01

49

Many Ways to Loop DNA  

PubMed Central

In the 1960s, I developed methods for directly visualizing DNA and DNA-protein complexes using an electron microscope. This made it possible to examine the shape of DNA and to visualize proteins as they fold and loop DNA. Early applications included the first visualization of true nucleosomes and linkers and the demonstration that repeating tracts of adenines can cause a curvature in DNA. The binding of DNA repair proteins, including p53 and BRCA2, has been visualized at three- and four-way junctions in DNA. The trombone model of DNA replication was directly verified, and the looping of DNA at telomeres was discovered. PMID:24005675

Griffith, Jack D.

2013-01-01

50

Shape Savvy  

NSDL National Science Digital Library

Help your students identify these different shapes! Learn your shapes with Big Bird s Shapes and then Make Designs with Shapes to create objects! You better know your colors to Paint the Shapes correctly! ...

Popwell, Ms.

2010-09-22

51

Concepts for generating optimum vertical flight profiles  

NASA Technical Reports Server (NTRS)

Algorithms for generating optimum vertical profiles are derived and examined. These algorithms form the basis for the design of onboard flight management concepts. The variations in the optimum vertical profiles (resulting from these concepts) due to variations in wind, takeoff weight, and range-to-destination are presented. Further considerations for mechanizing two different onboard methods of computing near-optimum flight profiles are then outlined. Finally, the results are summarized, and recommendations are made for further work. Technical details of optimum trajectory design, steering requirements for following these trajectories, and off-line computer programs for testing the concepts are included.

Sorensen, J. A.

1979-01-01

52

Optimum Reset of Ship's Inertial Navigation System  

Microsoft Academic Search

Optimum linear filter and control theory is applied to the practical problem of supplementing an inertial navigation system with discrete reference information. The information takes the form of position obtained from Loran C or Decca, for example, and occasional azimuth fixes obtained from star sightings. In particular, optimum use of this information is discussed for the Ship's Inertial Navigation System

B. E. Bona; Robert J. Smay

1966-01-01

53

OPTIMUM LIGHT AND TEMPERATURE REQUIREMENTS FOR  

E-print Network

OPTIMUM LIGHT AND TEMPERATURE REQUIREMENTS FOR GYMNODINIUM SPLENDENS, A LARVAL FISH FOOD ORGANISMI. The purpose of this paper is to establish the optimum conditions of light and temperature for G. splendens (prepared by autoclaving equal weights of untilled loam and glass distilled water fol- lowed by filtration

54

Feature Exploration for Mining Coronal Loops from Solar Images  

Microsoft Academic Search

Abstract , Coronal loops are especially important in analyzing some important phenomena,related to the Sun such as the,controversial,coronal,heating,problem.,The analysis requires,astrophysicists to manually,sift through,thousands,of images,in order to acquire images containing coronal loops. Thus, the motivati on to detect these loops automatically. Since coronal loops do not have a perfect shape and are easy to confuse with other solar events, feature selection

Nurcan Durak; Olfa Nasraoui

2008-01-01

55

Water Stream "Loop-the-Loop"  

ERIC Educational Resources Information Center

Discusses the design of a modified loop-the-loop apparatus in which a water stream is used to illustrate centripetal forces and phenomena of high-velocity hydrodynamics. Included are some procedures of carrying out lecture demonstrations. (CC)

Jefimenko, Oleg

1974-01-01

56

Topological defects and the optimum size of DNA condensates.  

PubMed Central

Under a wide variety of conditions, the addition of condensing agents to dilute solutions of random-coil DNA gives rise to highly compact particles that are toroidal in shape. The size of these condensates is remarkably constant and is largely independent of DNA molecular weight and basepair sequence, and of the nature of condensing agent (e.g., multivalent cation, polymers, or added cosolvent). We show how this optimum size is determined by the interactions between topological defects, which unavoidably strain the circumferentially wound DNA strands in the torus. PMID:9675173

Park, S Y; Harries, D; Gelbart, W M

1998-01-01

57

Optimum structure of Whipple shield against hypervelocity impact  

NASA Astrophysics Data System (ADS)

Hypervelocity impact of a spherical aluminum projectile onto two spaced aluminum plates (Whipple shield) was simulated to estimate an optimum structure. The Smooth Particle Hydrodynamics (SPH) code which has a unique migration scheme from a rectangular coordinate to an axisymmetic coordinate was used. The ratio of the front plate thickness to sphere diameter varied from 0.06 to 0.48. The impact velocities considered here were 6.7 km/s. This is the procedure we explored. To guarantee the early stage simulation, the shapes of debris clouds were first compared with the previous experimental pictures, indicating a good agreement. Next, the debris cloud expansion angle was predicted and it shows a maximum value of 23 degree for thickness ratio of front bumper to sphere diameter of 0.23. A critical sphere diameter causing failure of rear wall was also examined while keeping the total thickness of two plates constant. There exists an optimum thickness ratio of front bumper to rear wall, which is identified as a function of the size combination of the impacting body, front and rear plates. The debris cloud expansion-correlated-optimum thickness ratio study provides a good insight on the hypervelocity impact onto spaced target system.

Lee, M.

2014-05-01

58

Resynthesis and retiming for optimum partial scan  

Microsoft Academic Search

An effective partial scan approach selects flip-flops (FPs) in the minimum feedback vertex set (MFVS) of the FF dependency graph, so that all loops, except self-loops, are broken. However, the MFVS of the circuit (the minimum number of gates whose removal makes the circuit acyclic) is a lower bound and in many cases, significantly smaller than the MFVS of the

Srimat T. Chakradhar; Sujit Dey

1999-01-01

59

Quantum loop programs  

E-print Network

Loop is a powerful program construct in classical computation, but its power is still not exploited fully in quantum computation. The exploitation of such power definitely requires a deep understanding of the mechanism of quantum loop programs. In this paper, we introduce a general scheme of quantum loops and describe its computational process. The notions of termination and almost termination are proposed for quantum loops, and the function computed by a quantum loop is defined. To show their expressive power, quantum loops are applied in describing quantum walks. Necessary and sufficient conditions for termination and almost termination of a general quantum loop on any mixed input state are presented. A quantum loop is said to be (almost) terminating if it (almost) terminates on any input state. We show that a quantum loop is almost terminating if and only if it is uniformly almost terminating. It is observed that a small disturbance either on the unitary transformation in the loop body or on the measurement in the loop guard can make any quantum loop (almost) terminating. Moreover, a representation of the function computed by a quantum loop is given in terms of finite summations of matrices. To illustrate the notions and results obtained in this paper, two simplest classes of quantum loop programs, one qubit quantum loops, and two qubit quantum loops defined by controlled gates, are carefully examined.

Mingsheng Ying; Yuan Feng

2006-05-25

60

Optimum temperature staging of cryogenic refrigeration system  

NASA Astrophysics Data System (ADS)

Optimum temperature staging is investigated to minimize entropy generation in a multi-stage cryogenic refrigeration cycle. It is found that the best intermediate temperature distribution is to have the same high to low temperature ratio at each stage of the system. As an example, the result is applied to the design of a cryogenic cascade thermoelectric cooler to find the optimum size distribution of each stage.

Jeong, S.; Smith, J. L.

61

Computational Complexity of Optimum Multiuser Detection  

Microsoft Academic Search

Optimum centralized demodulation of the independent data streams transmitted simultaneously by several users through a Code\\u000a Division Multiple-Access channel is considered. Each user sends an arbitrary assigned signal waveform, which is linearly modulated\\u000a by symbols drawn from a finite alphabet. If the users are asynchronous, the optimum multiuser detector can be implemented\\u000a by a Viterbi algorithm whose time-complexity is linear

Sergio Verdú

1989-01-01

62

Optimum Design of High-Speed Prop-Rotors  

NASA Technical Reports Server (NTRS)

An integrated multidisciplinary optimization procedure is developed for application to rotary wing aircraft design. The necessary disciplines such as dynamics, aerodynamics, aeroelasticity, and structures are coupled within a closed-loop optimization process. The procedure developed is applied to address two different problems. The first problem considers the optimization of a helicopter rotor blade and the second problem addresses the optimum design of a high-speed tilting proprotor. In the helicopter blade problem, the objective is to reduce the critical vibratory shear forces and moments at the blade root, without degrading rotor aerodynamic performance and aeroelastic stability. In the case of the high-speed proprotor, the goal is to maximize the propulsive efficiency in high-speed cruise without deteriorating the aeroelastic stability in cruise and the aerodynamic performance in hover. The problems studied involve multiple design objectives; therefore, the optimization problems are formulated using multiobjective design procedures. A comprehensive helicopter analysis code is used for the rotary wing aerodynamic, dynamic and aeroelastic stability analyses and an algorithm developed specifically for these purposes is used for the structural analysis. A nonlinear programming technique coupled with an approximate analysis procedure is used to perform the optimization. The optimum blade designs obtained in each case are compared to corresponding reference designs.

Chattopadhyay, Aditi; McCarthy, Thomas Robert

1993-01-01

63

Fast flux locked loop  

DOEpatents

A flux locked loop for providing an electrical feedback signal, the flux locked loop employing radio-frequency components and technology to extend the flux modulation frequency and tracking loop bandwidth. The flux locked loop of the present invention has particularly useful application in read-out electronics for DC SQUID magnetic measurement systems, in which case the electrical signal output by the flux locked loop represents an unknown magnetic flux applied to the DC SQUID.

Ganther, Jr., Kenneth R. (Olathe, KS); Snapp, Lowell D. (Independence, MO)

2002-09-10

64

Rigged Configurations and Cylindric Loop Schur Functions  

E-print Network

Rigged configurations are known to provide action-angle variables for remarkable discrete dynamical systems known as box-ball systems. We conjecture an explicit piecewise-linear formula to obtain the shapes of a rigged configuration from a tensor product of one-row crystals. We introduce cylindric loop Schur functions and show that they are invariants of the geometric R-matrix. Our piecewise-linear formula is obtained as the tropicalization of ratios of cylindric loop Schur functions. We prove our conjecture for the first shape of a rigged configuration, thus giving a piecewise-linear formula for the lengths of the solitons of a box-ball system.

Thomas Lam; Pavlo Pylyavskyy; Reiho Sakamoto

2014-10-16

65

Optimum Electron Distributions for Space Charge Dominated Beams in Photoinjectors  

SciTech Connect

The optimum photo-electron distribution from the cathode of an RF photoinjector producing a space charge dominated beam is a uniform distribution contained in an ellipsoid. For such a bunch distribution, the space charge forces are linear and the emittance growth induced by those forces is totally reversible and consequently can be compensated. With the appropriate tuning of the emittance compensation optics, the emittance, at the end of photoinjector beamline, for an ellipsoidal laser pulse, would only have two contributions, the cathode emittance and the RF emittance. For the peak currents of 50A and 100 A required from the SBand and L-Band RF gun photoinjectors discussed here, the RF emittance contribution is negligible. If such an ellipsoidal photo-electron distribution were available, the emittance at the end of the beamline could be reduced to the cathode emittance. Its value would be reduced by more than 40% from that obtained using cylindrical shape laser pulses. This potentially dramatic improvement warrants review of the challenges associated with the production of ellipsoidal photo-electrons. We assume the photo-electrons emission time to be short enough that the ellipsoidal electron pulse shape will come directly from the laser pulse. We shift the challenge to ellipsoidal laser pulse shaping. To expose limiting technical issues, we consider the generation of ellipsoidal laser pulse shape in terms of three different concepts.

Limborg-Deprey, C.; Bolton, P.R.; /SLAC

2006-06-15

66

Shape Hunt  

NSDL National Science Digital Library

Students will go on a shape hunt in the classroom or designated area. During the shape hunt, students will draw pictures of the shapes they find and the object that it is found by, in order to show the position of the shape. After the shape hunt, students will use Timed-Pair-Share to explain to peers what shapes they found and their relative positions.

Hauptli, Meghan

2012-06-11

67

Optimum Suction Distribution for Transition Control  

NASA Technical Reports Server (NTRS)

The optimum suction distribution which gives the longest laminar region for a given total suction is computed. The goal here is to provide the designer with a method to find the best suction distribution subject to some overall constraint applied to the suction. We formulate the problem using the Lagrangian multiplier method with constraints. The resulting non-linear system of equations is solved using the Newton-Raphson technique. The computations are performed for a Blasius boundary layer on a flat-plate and crossflow cases. For the Blasius boundary layer, the optimum suction distribution peaks upstream of the maximum growth rate region and remains flat in the middle before it decreases to zero at the end of the transition point. For the stationary and travelling crossflow instability, the optimum suction peaks upstream of the maximum growth rate region and decreases gradually to zero.

Balakumar, P.; Hall, P.

1996-01-01

68

learning shapes  

NSDL National Science Digital Library

Identify, descirbe, and create simple geometric figures. This is a fun way to introduce the basic shapes to students through interactive activities. Find out about different shaes from the following link: draw me shapes Have fun with shapes with the following links: puzzle draw shapes Sesame Street Finish up the day by making some books: book ...

Grimnes, Mrs.

2007-10-17

69

Optimum Transfer Guide: Journalism Why Study Journalism?  

E-print Network

Optimum Transfer Guide: Journalism Why Study Journalism? Augmenting Journalism education based attributes of print, broadcast, and online news. Why Journalism at Texas Tech? The College of Mass in a foreign country. Talk to your advisor for more information. Graduate Education The College of Mass

Gelfond, Michael

70

Optimum Current Distributions on Vertical Antennas  

Microsoft Academic Search

The theoretical optimum current distribution on a vertical antenna of given length is defined as that current distribution giving the maximum possible field strength on the horizon for a given power output. The problem of determining such distributions is set up as a problem in the calculus of variations, and solution functions are derived for antennas varying in length from

G. A. Miller

1943-01-01

71

Optimum ethane recovery in conventional turboexpander process  

Microsoft Academic Search

Ethane recovery in a conventional turboexpander process is optimized considering different demethanizer pressures and different feeds: a lean gas and a rich one. The design variables are varied, while meeting process constraints, in order to find the optimum conditions achieving the maximum profit. The analysis covers the whole process including the refrigeration part, and the entire typical demethanizer pressure range.

R. Chebbi; N. S. Al-Amoodi; N. M. Abdel Jabbar; G. A. Husseini; K. A. Al Mazroui

2010-01-01

72

Optimum Integration of Aircraft Navigation Systems  

Microsoft Academic Search

A current problem in aircraft navigation is determining how to effect alow cost navigation system consistent with required mission operationswhich will render a high degree of accuracy and reliability. One wayto achieve this is through optimum integration of equipment,subsystems, and computer mechanizations. Consistent with this approach,the overall objectives of this paper are to show the advantages of anoptimally integrated aircraft

William Zimmerman

1969-01-01

73

Quantitative characterization of morphological polymorphism of handwritten characters loops.  

PubMed

A methodology based on Fourier descriptors that was previously validated has been applied to 13 writers in order to quantify the polymorphism degree of the shape of the loops of the handwritten characters a, d, o and q. In a first step, the discriminating power of the parameters extracted from these letters was investigated. The loop of the letter d appeared to be the most discriminant with a correct classification rate of 82.4%, whereas the least discriminant one was the loop of the letter o (69.7%). The second aim of the study was to extract grouping characteristics which make it possible to discriminate between writer sets, whatever the letter. Trends in the writing of loops could effectively be shown: the 13 writers of the study were separated into five main groups according to the shape and surface of their loops. The most discriminating features between the writer groups were the importance of the loops elongation and the surface of the loops. Finally, the differences between writers belonging to distinct groups could be characterized more precisely, and differences between writers belonging to the same group were revealed; the individual writings were distinguished by the variability of the parameters of shape and surface of their loops and the morphological distances between its different letters. The correct classification rates reached in this study suggest that carrying out an expertise of fragmentary samples of handwriting comprising only some loops is completely possible. PMID:16524677

Marquis, R; Taroni, F; Bozza, S; Schmittbuhl, M

2006-12-20

74

Preisach modeling of piezoceramic and shape memory alloy hysteresis  

Microsoft Academic Search

Smart materials such as piezoceramics and shape memory alloys (SMAs) exhibit significant hysteresis and in order to estimate the effect on open and closed loop control a suitable model is needed. One promising candidate is the Preisach independent domain hysteresis model that is characterized by the congruent minor loop and wiping out properties. Comparable minor loop and decaying oscillation test

Declan Hughes; John T. Wen

1995-01-01

75

On the Calculation of Squaring Loss in Costas Loops with Arbitrary Arm Filters  

Microsoft Academic Search

The calculation of the optimum performance of suppressed carrier receivers with Costas loop tracking is directly related to evaluating the loop's so-called squaring loss. Recent work by the author and others presented specific numerical results for this loss when the input data were biphase-L(Manchester coded) and the Costas loop arm filters were of then-pole Butterworth type. These results were largely

M. Simon

1978-01-01

76

On the optimality of the MAP estimation loop for carrier phase tracking BPSK and QPSK signals  

NASA Technical Reports Server (NTRS)

Starting with MAP estimation theory as a basis for optimally estimating carrier phase of BPSK and QPSK modulations, it is shown in this paper that the closed loop phase trackers, which are motivated by this approach, are indeed closed loop optimum in the minimum mean-square phase tracking jitter sense. The corresponding squaring loss performance of these so-called MAP estimation loops is compared with that of more practical implementations wherein the hyperbolic tangent nonlinearity is approximated by simpler functions.

Simon, M. K.

1979-01-01

77

'Optimum mobility' facelift. Part 1 - the theory.  

PubMed

Traditional rhytidectomy techniques, such as the cutaneous lift, the superficial musculoaponeurotic system lift, the deep plane lift and the subperiosteal lift, are mostly differentiated by their different planes of dissection. As well, many of these techniques consider the complete mobilization of tissues a prerequisite for obtaining a satisfactory result.However, is it true that the result of a rhytidectomy is linked to the choice of the dissection plane? Also, is it true that the adequacy of the surgical mobilization of tissues is vital to the outcome? The present paper discusses the above questions and introduces a factor that is believed to be crucial to the planning and success of a rhytidectomy: facial tissue mobility. The analysis of this mobility is presented and leads to the development of three theories: 'intrinsic mobility', 'surgically induced mobility' and 'optimum mobility points'. These theories form the foundation of a rhytidectomy technique termed 'optimum mobility' facelift. PMID:19554118

Fanous, Nabil

2006-01-01

78

Shape Changing Airfoil  

NASA Technical Reports Server (NTRS)

Scoping of shape changing airfoil concepts including both aerodynamic analysis and materials-related technology assessment effort was performed. Three general categories of potential components were considered-fan blades, booster and compressor blades, and stator airfoils. Based on perceived contributions to improving engine efficiency, the fan blade was chosen as the primary application for a more detailed assessment. A high-level aerodynamic assessment using a GE90-90B Block 4 engine cycle and fan blade geometry indicates that blade camber changes of approximately +/-4deg would be sufficient to result in fan efficiency improvements nearing 1 percent. Constraints related to flight safety and failed mode operation suggest that use of the baseline blade shape with actuation to the optimum cruise condition during a portion of the cycle would be likely required. Application of these conditions to the QAT fan blade and engine cycle was estimated to result in an overall fan efficiency gain of 0.4 percent.

Ott, Eric A.

2005-01-01

79

Shape Builder  

NSDL National Science Digital Library

In this activity, students either create a shape, or the applet creates a random shape constructed of squares on a coordinate plane. Then the student computes the area and perimeter of the shape. This activity allows students to explore and compare the area and perimeter of simple shapes. This activity includes supplemental materials, including background information about the topics covered, a description of how to use the application, and exploration questions for use with the java applet.

2010-01-01

80

Optimized conical shaped charge design using the SCAP (Shaped Charge Analysis Program) code  

Microsoft Academic Search

The Shaped Charge Analysis Program (SCAP) is used to analytically model and optimize the design of Conical Shaped Charges (CSC). A variety of existing CSCs are initially modeled with the SCAP code and the predicted jet tip velocities, jet penetrations, and optimum standoffs are compared to previously published experimental results. The CSCs vary in size from 0.69 inch (1.75 cm)

Vigil

1988-01-01

81

Simulations of gyrosynchrotron microwave emission from an oscillating magnetic loop  

NASA Astrophysics Data System (ADS)

Radio observations of solar flares often reveal various periodic or quasi-periodic oscillations. Most likely, these oscillations are caused by MHD oscillations of flaring loops which modulate the radio emission via variations of the magnetic field and electron concentration. We perform numerical simulations of gyrosynchrotron radiation from a toroidal-shaped magnetic loop containing sausage-mode MHD oscillations. Different parameters of the loop and MHD oscillations and different loop orientations are considered. The simulation results are compared with the observations of the Nobeyama Radioheliograph.

Kuznetsov, Alexey; Reznikova, Veronika; Van Doorsselaere, Tom; Antolin, Patrick

82

Loop Quantum Cosmology.  

E-print Network

??In this thesis we present a detailedintroduction to loop quantum cosmologyfocusing on the Robertson-Walker cosmologieswith constant spatial curvature. The constructionof the quantum theory will be… (more)

Vandersloot, Kevin

2006-01-01

83

Equilibrium models of coronal loops that involve curvature and buoyancy  

E-print Network

We construct magnetostatic models of coronal loops in which the thermodynamics of the loop is fully consistent with the shape and geometry of the loop. This is achieved by treating the loop as a thin, compact, magnetic fibril that is a small departure from a force-free state. The density along the loop is related to the loop's curvature by requiring that the Lorentz force arising from this deviation is balanced by buoyancy. This equilibrium, coupled with hydrostatic balance and the ideal gas law, then connects the temperature of the loop with the curvature of the loop without resorting to a detailed treatment of heating and cooling. We present two example solutions: one with a spatially invariant magnetic Bond number (the dimensionless ratio of buoyancy to Lorentz forces) and the other with a constant radius of curvature of the loop's axis. We find that the density and temperature profiles are quite sensitive to curvature variations along the loop, even for loops with similar aspect ratios.

Hindman, Bradley W

2013-01-01

84

Optimum structural design with static aeroelastic constraints  

NASA Technical Reports Server (NTRS)

The static aeroelastic performance characteristics, divergence velocity, control effectiveness and lift effectiveness are considered in obtaining an optimum weight structure. A typical swept wing structure is used with upper and lower skins, spar and rib thicknesses, and spar cap and vertical post cross-sectional areas as the design parameters. Incompressible aerodynamic strip theory is used to derive the constraint formulations, and aerodynamic load matrices. A Sequential Unconstrained Minimization Technique (SUMT) algorithm is used to optimize the wing structure to meet the desired performance constraints.

Bowman, Keith B; Grandhi, Ramana V.; Eastep, F. E.

1989-01-01

85

Shape Detectives  

NSDL National Science Digital Library

In this hands-on lesson, students will become Shape Detectives as they identify the two-dimensional shapes, such as triangles, squares and rectangles, needed to build three-dimensional figures including rectangular prisms, square pyramids and cubes. The students will gain an understanding of how two-dimensional shapes are joined together to form three-dimensional figures as well as creating an edible example!

Ward, Stan

2012-07-31

86

Research of ultrasonic welding of polymer ring-shaped materials  

Microsoft Academic Search

The article considers the model of formation of weld seam of polymers by ultrasonic welding with ring-shaped working tool. Dependences of optimum amplitude of ultrasonic influence were ascertained according to diameter and width of the joint on the basis of the theoretical analysis of the process. The results of theoretical studies allow proposing the algorithm for optimum control of ultrasonic

Vladimir N. Khmelev; Aleksey N. Slivin; Aleksey D. Abramov

2010-01-01

87

Gravitons and loops  

Microsoft Academic Search

The recently proposed loop representation is used to quantize linearized general relativity. The Fock space of graviton states and its associated algebra of observables are represented in terms of functionals of loops. The ``reality conditions'' are realized by an inner product that is chiral asymmetric, resulting in a chiral-asymmetric ordering for the Hamiltonian, and, in an asymmetric description of the

Abhay Ashtekar; Carlo Rovelli; Lee Smolin

1991-01-01

88

What Controls DNA Looping?  

PubMed Central

The looping of DNA provides a means of communication between sequentially distant genomic sites that operate in tandem to express, copy, and repair the information encoded in the DNA base sequence. The short loops implicated in the expression of bacterial genes suggest that molecular factors other than the naturally stiff double helix are involved in bringing the interacting sites into close spatial proximity. New computational techniques that take direct account of the three-dimensional structures and fluctuations of protein and DNA allow us to examine the likely means of enhancing such communication. Here, we describe the application of these approaches to the looping of a 92 base-pair DNA segment between the headpieces of the tetrameric Escherichia coli Lac repressor protein. The distortions of the double helix induced by a second protein—the nonspecific nucleoid protein HU—increase the computed likelihood of looping by several orders of magnitude over that of DNA alone. Large-scale deformations of the repressor, sequence-dependent features in the DNA loop, and deformability of the DNA operators also enhance looping, although to lesser degrees. The correspondence between the predicted looping propensities and the ease of looping derived from gene-expression and single-molecule measurements lends credence to the derived structural picture. PMID:25167135

Perez, Pamela J.; Clauvelin, Nicolas; Grosner, Michael A.; Colasanti, Andrew V.; Olson, Wilma K.

2014-01-01

89

Shape Tool  

NSDL National Science Digital Library

This virtual manipulative allows you to create geometric shapes. Squares, triangles, rhombi, trapezoids and hexagons can be created, colored, enlarged, shrunk, rotated, reflected, sliced, and glued together.

Math, Illuminations N.

2009-01-15

90

Falling Loop Model  

NSDL National Science Digital Library

The EJS Falling Loop Model shows a conducting loop falling out of a uniform magnetic field. Users can change the size and orientation of the loop. If Ejs is installed, right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item allows for editing of the model. The Falling Loop model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_em_FallingLoop.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Cox, Anne

2009-09-24

91

Strong Shapes  

NSDL National Science Digital Library

Is a square stronger than a triangle? Use tongue depressors to build simple shapes. Then apply a little weight to them and see what happens! This activity comes with useful tips for building the shapes, like how to drill the wood without cracking it, and what drill works best.

Minnesota, Science M.

1995-01-01

92

On the optimum control of the wave equation  

NASA Astrophysics Data System (ADS)

Optimal open-loop and closed-loop controllers for distributed parameter systems are developed in this study. The wave equation representing the dynamics of many flexible systems with distributed mass and stiffness, is derived from the extended Hamilton's principle as an equation of motion. A frequency domain strategy is used to obtain the bang-off-bang time-optimal solution for a rest-to-rest maneuver of a slender uniform rod with one or two control inputs. The time-optimal control profiles for the wave equation are derived in closed form. To corroborate the optimality of the control profile derived for the infinite-dimensional model, a series of time-optimal control problems are solved for the finite-dimensional model, with increasing number of flexible modes. In the limit, the controllers show the convergence of the first and final switch of bang-bang controller of the discretized system to the first and final switch of bang-off-bang controller of the distributed parameter system in addition to the convergence of the maneuver time. The maneuver time of the distributed parameter system is compared to that of an equivalent rigid system and the coincidence of the time-optimal controllers of the distributed parameter and rigidized systems is illustrated for certain maneuvers. This implies that the residual energy of the distributed parameter system when it is subject to the time-optimal control profile for the rigidized system is zero for specific maneuvers. Collocated and noncollocated controller for a distributed parameter system whose dynamics is governed by the wave equation are designed using Lyapunov's direct method and a frequency domain approach, respectively. A time-delay relationship is derived in closed form for the noncollocated case. The gains which correspond to a pair of the closed-loop poles entering the right-half complex plane and the gains which correspond to the closed-loop poles being located at the left extreme of the root-locus for each mode are obtained. The overall optimum gain which minimizes a quadratic cost, in the range of the obtained gains for each mode is determined. The effect of sensor location on the observability of the system is investigated when a boundary control actuation is used. Finally, a design approach that results in optimal passive controllers for flexible structures is proposed. The optimal parameters of the passive controllers are determined by minimizing the Integral of the Time Absolute Error (ITAE), subject to control constraints. Passive input-output transfer functions for the plants are obtained by selecting appropriate outputs. The benchmark floating oscillator and two models of overhead cranes are selected to illustrate the design technique. The suspended cable of the overhead crane is first assumed to be rigid and then, the wave equation is used to represent the dynamics of the cable. The simulation results illustrate the effectiveness of the proposed design technique.

Alli, Hasan

93

A preliminary assessment of Soviet development of optimum signal discrimination techniques: Optimum space-time processing  

NASA Astrophysics Data System (ADS)

This study provides an overview of Soviet work in the subject of optimum signal discrimination techniques. Its purpose is to aid U.S. scientists in becoming more familiar with an extensive signal processing effort of which they undoubtedly have had little prior awareness. It provides general substantive comment and bibliographic resource materials. If this work is successful in accomplishing its goal, it will serve as an example of reverse technology transfer. The Soviets have, for several decades, taken a more rigorous statistical approach to the study of oceanic processes and the theory of detection signals in the ocean environment than has the United States. The Soviets view this environmental as non-Gaussian, nonstationary, and nonwhite, and do not avoid the complications this presents to the formulation of the theory of optimum signal detection and estimation. There appears to be poor U.S. access to this work. The United States would probably benefit from selected uses of Soviet theory and algorithm developments in this topic. Soviet development of optimum signal detection and estimation techniques is broadly based, covering various aspects of radar, sonar, and communications. They have an extensive program in the development of optimum space-time processing (OSTP) and have extended the theory further than has the U.S. Their effort is based on the Karhunen-Loeve expansion extended to nonstationary space-time signals and noise.

Caruthers, J. W.

1982-10-01

94

Multiprotein DNA looping  

E-print Network

DNA looping plays a fundamental role in a wide variety of biological processes, providing the backbone for long range interactions on DNA. Here we develop the first model for DNA looping by an arbitrarily large number of proteins and solve it analytically in the case of identical binding. We uncover a switch-like transition between looped and unlooped phases and identify the key parameters that control this transition. Our results establish the basis for the quantitative understanding of fundamental cellular processes like DNA recombination, gene silencing, and telomere maintenance.

Jose M. G. Vilar; Leonor Saiz

2006-03-17

95

Multiprotein DNA Looping  

NASA Astrophysics Data System (ADS)

DNA looping plays a fundamental role in a wide variety of biological processes, providing the backbone for long range interactions on DNA. Here we develop the first model for DNA looping by an arbitrarily large number of proteins and solve it analytically in the case of identical binding. We uncover a switchlike transition between looped and unlooped phases and identify the key parameters that control this transition. Our results establish the basis for the quantitative understanding of fundamental cellular processes like DNA recombination, gene silencing, and telomere maintenance.

Vilar, Jose M. G.; Saiz, Leonor

2006-06-01

96

Natively Unstructured Loops Differ from Other Loops  

PubMed Central

Natively unstructured or disordered protein regions may increase the functional complexity of an organism; they are particularly abundant in eukaryotes and often evade structure determination. Many computational methods predict unstructured regions by training on outliers in otherwise well-ordered structures. Here, we introduce an approach that uses a neural network in a very different and novel way. We hypothesize that very long contiguous segments with nonregular secondary structure (NORS regions) differ significantly from regular, well-structured loops, and that a method detecting such features could predict natively unstructured regions. Training our new method, NORSnet, on predicted information rather than on experimental data yielded three major advantages: it removed the overlap between testing and training, it systematically covered entire proteomes, and it explicitly focused on one particular aspect of unstructured regions with a simple structural interpretation, namely that they are loops. Our hypothesis was correct: well-structured and unstructured loops differ so substantially that NORSnet succeeded in their distinction. Benchmarks on previously used and new experimental data of unstructured regions revealed that NORSnet performed very well. Although it was not the best single prediction method, NORSnet was sufficiently accurate to flag unstructured regions in proteins that were previously not annotated. In one application, NORSnet revealed previously undetected unstructured regions in putative targets for structural genomics and may thereby contribute to increasing structural coverage of large eukaryotic families. NORSnet found unstructured regions more often in domain boundaries than expected at random. In another application, we estimated that 50%–70% of all worm proteins observed to have more than seven protein–protein interaction partners have unstructured regions. The comparative analysis between NORSnet and DISOPRED2 suggested that long unstructured loops are a major part of unstructured regions in molecular networks. PMID:17658943

Schlessinger, Avner; Liu, Jinfeng; Rost, Burkhard

2007-01-01

97

A loop quantum multiverse?  

NASA Astrophysics Data System (ADS)

Inhomogeneous space-times in loop quantum cosmology have come under better control with recent advances in effective methods. Even highly inhomogeneous situations, for which multiverse scenarios provide extreme examples, can now be considered at least qualitatively.

Bojowald, Martin

2013-02-01

98

Diffusion of Wilson Loops  

E-print Network

A phenomenological analysis of the distribution of Wilson loops in SU(2) Yang-Mills theory is presented in which Wilson loop distributions are described as the result of a diffusion process on the group manifold. It is shown that, in the absence of forces, diffusion implies Casimir scaling and, conversely, exact Casimir scaling implies free diffusion. Screening processes occur if diffusion takes place in a potential. The crucial distinction between screening of fundamental and adjoint loops is formulated as a symmetry property related to the center symmetry of the underlying gauge theory. The results are expressed in terms of an effective Wilson loop action and compared with various limits of SU(2) Yang-Mills theory.

A. M. Brzoska; F. Lenz; J. W. Negele; M. Thies

2004-12-01

99

Wilson loops in supersymmetric gauge theories  

NASA Astrophysics Data System (ADS)

This thesis is devoted to several exact computations in four-dimensional supersymmetric gauge field theories. In the first part of the thesis we prove conjecture due to Erickson-Semenoff-Zarembo and Drukker-Gross which relates supersymmetric circular Wilson loop operators in the N = 4 supersymmetric Yang-Mills theory with a Gaussian matrix model. We also compute the partition function and give a new matrix model formula for the expectation value of a supersymmetric circular Wilson loop operator for the pure N = 2 and the N* = 2 supersymmetric Yang-Mills theory on a four-sphere. Circular supersymmetric Wilson loops in four-dimensional N = 2 superconformal gauge theory are treated similarly. In the second part we consider supersymmetric Wilson loops of arbitrary shape restricted to a two-dimensional sphere in the four-dimensional N = 4 supersymmetric Yang-Mills theory. We show that expectation value for these Wilson loops can be exactly computed using a two-dimensional theory closely related to the topological two-dimensional Higgs-Yang-Mills theory, or two-dimensional Yang-Mills theory for the complexified gauge group.

Pestun, Vasily

100

An integrated optimum design approach for high speed prop rotors  

NASA Technical Reports Server (NTRS)

The objective is to develop an optimization procedure for high-speed and civil tilt-rotors by coupling all of the necessary disciplines within a closed-loop optimization procedure. Both simplified and comprehensive analysis codes are used for the aerodynamic analyses. The structural properties are calculated using in-house developed algorithms for both isotropic and composite box beam sections. There are four major objectives of this study. (1) Aerodynamic optimization: The effects of blade aerodynamic characteristics on cruise and hover performance of prop-rotor aircraft are investigated using the classical blade element momentum approach with corrections for the high lift capability of rotors/propellers. (2) Coupled aerodynamic/structures optimization: A multilevel hybrid optimization technique is developed for the design of prop-rotor aircraft. The design problem is decomposed into a level for improved aerodynamics with continuous design variables and a level with discrete variables to investigate composite tailoring. The aerodynamic analysis is based on that developed in objective 1 and the structural analysis is performed using an in-house code which models a composite box beam. The results are compared to both a reference rotor and the optimum rotor found in the purely aerodynamic formulation. (3) Multipoint optimization: The multilevel optimization procedure of objective 2 is extended to a multipoint design problem. Hover, cruise, and take-off are the three flight conditions simultaneously maximized. (4) Coupled rotor/wing optimization: Using the comprehensive rotary wing code CAMRAD, an optimization procedure is developed for the coupled rotor/wing performance in high speed tilt-rotor aircraft. The developed procedure contains design variables which define the rotor and wing planforms.

Chattopadhyay, Aditi; Mccarthy, Thomas R.

1995-01-01

101

Hot giant loop holography  

SciTech Connect

We argue that there is a phase transition in the expectation value of the Polyakov loop operator in the large N limit of the high temperature deconfined phase of N=4 Yang-Mills theory on a spatial S{sup 3}. It occurs for the large completely symmetric representation of the SU(N) symmetry group. We speculate that this transition is reflected in the D-branes which are the string theory duals of giant loops.

Grignani, Gianluca [Dipartimento di Fisica, Universita di Perugia, INFN Sezione di Perugia, Via A. Pascoli, 06123 Perugia (Italy); Karczmarek, Joanna L.; Semenoff, Gordon W. [Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1 (Canada)

2010-07-15

102

Balancing Shapes  

NSDL National Science Digital Library

"Students will balance shapes on the pan balance applet to study equality, essential to understanding algebra. Equivalent relationships will be recognized when the pans balance, demonstrating the properties of equality." (from NCTM's Illuminations)

Mathematics, Illuminations N.

2009-10-26

103

Shape A Shape B Shape C Shape D Wave Structure  

E-print Network

be derived from recorded sounds. The shape of the segment affects the smoothness of the transient segment's starting amplitude is the previous segment's ending amplitude. This amplitude transient lasts

Miranda, Eduardo Reck

104

The Cinderella Loop Project  

NASA Astrophysics Data System (ADS)

The solar loop observed off the northeast limb on 1999 Nov 6 (a.k.a. the Cinderella Loop) is one of the few examples of a loop on the limb observed with all three of the following imaging instruments: TRACE, EIT on SOHO, and SXT on Yohkoh. In this project we investigate the differences that result when examining the Cinderella Loop with one instrument compared with another. For example, what are the loop temperature and emission measure differences that result from the increased special resolution between the two EUV imagers? More specifically, TRACE and EIT have almost identical temperature responses to coronal plasma. Do the observations taken with the higher-resolution TRACE instrument (with 0.5 arcsec pixels) produce statistically different results than those observations taken with the lower-resolution EIT instrument (with 2.6 arcsec pixels)? In addition, the special resolution of EIT and SXT is similar, but the temperature responses of the two instruments are quite different. Are the two instruments even seeing the same loop strands? If they are, what are the temperatures and emission measures that result from the analysis of the two data sets? How do these results change after background subtraction? This presentation will answer these questions. Solar physics research at the University of Memphis is supported by NASA grants NAG5-9783 and NAG5-12096.

Schmelz, J.; Beene, J.; Buchanan, J.; Coyle, T.; Douglass, J.; Nasraoui, K.; O'Connor, J.; Roames, J.; Scott, M.

105

Optimum design of spectrometer in FD-OCT  

NASA Astrophysics Data System (ADS)

Fourier-domain optical coherence tomography (FDOCT) has attained popularity due to its static parts, high imaging speed[1], and high sensitivity[2]. FDOCT makes use of spectral interferometry and collects data in the spectral domain, either using a spectrometer with a detector array or by a single point detector with a wavelength-swept light source[3]. The axial resolution depends on the bandwidth of the spectrum. The spectral response of the spectrometer is always desired to be flat in order to have the best axial resolution corresponding to the light source spectrum. Unfortunately, the optics consisting of the spectrometer usually shape the spectrum. The optimum optics design and alignment will minimize the spectral shaping. The frequency response simulation by advanced optical design software displays a clear picture for our design and system alignment. The axial imaging range of FDOCT according to the Fourier transform relationship is ultimately limited by a fringe visibility degrading curve with increasing imaging depth due to the spectral sampling spacing called the fall-off [4]. This limitation is significant for applications of spectrometer-based FDOCT where a long imaging range is desirable (e.g the anterior segment of the eye), especially when imaging uses 1.3 ?m light because large pixel-count arrays are not currently commercially available. Although resolving complex-conjugate ambiguity[5] and Sub-pixel shifting[6] have extended the image range, the imaging range of FDOCT is still limited by the fall-off, which is a primary concern in the design of a spectrometer-based FDOCT system. A mathematical model of spectrometer-based FDOCT can aid in understanding of signal formation, including fall-off [ref OL].

Hu, Zhilin; Rollins, Andrew M.

2007-02-01

106

Devised loop-in-loop technique in mitral valve repair.  

PubMed

The loop technique is useful for multiple chordal reconstructions in mitral valve repair. Although it is easy to anchor the loop to the tip of the prolapsed leaflet, take-down of the anchored loop is not easy. The devised loop-in-loop technique makes intraoperative adjustment of the neochordae quick and easy. This article describes a straightforward and reproducible method for secure anchoring and, if necessary, take-down of neochordae using the loop-in-loop technique for mitral valve repair. PMID:24887864

Tokunaga, Shigehiko; Yasuda, Shota; Masuda, Munetaka

2014-11-01

107

Optimum Construction of Heating Coil for Domestic Induction Cooker  

NASA Astrophysics Data System (ADS)

The design and optimization of the parameters of heating coil is very important for the analytical analysis of high frequency inverter fed induction cooker. Moreover, accurate prediction of high frequency winding loss (i.e., losses due to skin and proximity effects) is necessary as the induction cooker used in power electronics applications. At high frequency current penetration in the induction coil circuit is very difficult for conducting wire due to skin-effect. To eradicate the skin effect heating coil is made up of bundle conductor i.e., litz wire. In this paper inductances and AC resistances of a litz-wire are calculated and optimized by considering the input parameters like wire type, shape, number of strand, number of spiral turn, number of twist per feet of heating coil and operating frequency. A high frequency half bridge series resonant mirror inverter circuit is used in this paper and taking the optimum values of inductance and ac resistance the circuit is simulated through PSPICE simulations. It has been noticed that the results are feasible enough for real implementation.

Sinha, Dola; Bandyopadhyay, Atanu; Sadhu, Pradip Kumar; Pal, Nitai

2010-10-01

108

Shape memory effect heat engine performance  

Microsoft Academic Search

The performance of a shape memory effect heat engine has been evaluated taking into account the heat transfer to the working element, hysteresis effects, elasticity and heat losses. It is shown that there exists an optimum stress required for maximum power output. The maximum power output is found to increase with increasing cycle temperature difference, increasing cycle strain, increasing working

P. G. McCormick

1986-01-01

109

Optimum structure with homogeneous optimum cellular material for maximum fundamental frequency  

Microsoft Academic Search

Ultra-light cellular materials exhibit high stiffness\\/strength to weight ratios and bring opportunity for multifunctional\\u000a performance. One of their potential applications is to build structure with optimum dynamic performance, which is extremely\\u000a important for some structural parts in vehicle engineering and attracts a great attention. This paper presents a two-scale\\u000a optimization method and aims at finding optimal configurations of macro structures

Bin Niu; Jun Yan; Gengdong Cheng

2009-01-01

110

Optimum deposition conditions of ultrasmooth silver nanolayers  

PubMed Central

Reduction of surface plasmon-polariton losses due to their scattering on metal surface roughness still remains a challenge in the fabrication of plasmonic devices for nanooptics. To achieve smooth silver films, we study the dependence of surface roughness on the evaporation temperature in a physical vapor deposition process. At the deposition temperature range 90 to 500 K, the mismatch of thermal expansion coefficients of Ag, Ge wetting layer, and sapphire substrate does not deteriorate the metal surface. To avoid ice crystal formation on substrates, the working temperature of the whole physical vapor deposition process should exceed that of the sublimation at the evaporation pressure range. At optimum room temperature, the root-mean-square (RMS) surface roughness was successfully reduced to 0.2 nm for a 10-nm Ag layer on sapphire substrate with a 1-nm germanium wetting interlayer. Silver layers of 10- and 30-nm thickness were examined using an atomic force microscope (AFM), X-ray reflectometry (XRR), and two-dimensional X-ray diffraction (XRD2). PACS 63.22.Np Layered systems; 68. Surfaces and interfaces; thin films and nanosystems (structure and nonelectronic properties); 81.07.-b Nanoscale materials and structures: fabrication and characterization PMID:24685115

2014-01-01

111

Connecting PHP and PHP Loops  

E-print Network

Connecting PHP and MySQL 1 #12;Outline · PHP Loops · PHPMyAdmin · Introducing SQL · Connecting Database from PHP · Exercises 2 #12;Loops · A loop statement is a control structure that repeatedly PHP supports the C style while loop ­ The body of the cycle

Graham, Nick

112

Diamagnetic loop for KSTAR.  

NASA Astrophysics Data System (ADS)

Three sets of diamagnetic loop (DL), at different locations, are designed to measure diamagnetic flux during a plasma discharge in the KSTAR machine. Each set consists of two concentric poloidal loops, and it is used for the diamagnetic flux measurement with the compensation of a ripple from to the power supply producing a toroidal field and a pick-up signal from the poloidal field due to the misalignment in the installation. One set is installed on inner wall of the vacuum vessel for the flux measurement at the first plasma in the KSTAR machine. It is located at a toroidal angle in the vacuum vessel, and the gap distance between inner and outer loops is 2 cm. An accurate position measurement of the two loops is done by using a laser tracker system after the installation. The in-situ calibration of the loops is done from the toroidal flux measurement. In the measurement, the electric current of less than 100A is applied to the toroidal field coils. In this work, present status of the DL for the initial measurement in the KSTAR machine will be presented.

Bak, Jun-Gyo; Lee, Sang-Gon; Ka, Eun-Mie

2007-11-01

113

The Cinderella loop project  

NASA Astrophysics Data System (ADS)

The solar loop that formed off the northeast limb of the Sun on 1999 November 6 (a.k.a. the Cinderella loop) is one of the few examples of a loop on the limb observed with all three of the following imaging instruments: the Transition Region and Coronal Explorer (TRACE), the SOHO Extreme-ultraviolet Imaging Telescope (EIT), and the Yohkoh Soft X-ray Telescope (SXT). In this project we investigate the temperature differences that result when examining the Cinderella loop with one instrument compared with another. For example, what temperature differences result from the increased spatial resolution between the two EUV imagers? More specifically, given that TRACE and EIT have almost identical temperature response to coronal plasma, does the different spatial resolution of TRACE (with 0.5? pixels) and EIT (with 2.6? pixels) produce statistically different results? We find that the answer is no, and that our results do not change after background subtraction. In addition, the spatial resolution of EIT and SXT is similar, but the temperature responses of the two instruments are quite different. The two instruments do not seem to be viewing the same loop strands, and the plasma temperature differences are significant.

Schmelz, J. T.; Beene, J.; Coyle, T.; Douglass, J.; Nasraoui, K.; O'Connor, J.; Roames, J.; Scott, M.

2006-01-01

114

The Energy Landscape of Hyperstable LacI-DNA Loops  

NASA Astrophysics Data System (ADS)

The Escherichia coli LacI protein represses transcription of the lac operon by blocking access to the promoter through binding at a promoter-proximal DNA operator. The affinity of tetrameric LacI (and therefore the repression efficiency) is enhanced by simultaneous binding to an auxiliary operator, forming a DNA loop. Hyperstable LacI-DNA loops were previously shown to be formed on DNA constructs that include a sequence-directed bend flanked by operators. Biochemical experiments showed that two such constructs (9C14 and 11C12) with different helical phasing between the operators and the DNA bend form different DNA loop shapes. The geometry and topology of the loops and the relevance of alternative conformations suggested by probable flexible linkers in LacI remain unclear. Bulk and single molecule fluorescence resonance energy transfer (SM-FRET, with D. English) experiments on a dual fluorophore-labeled 9C14-LacI loop demonstrate that it adopts a single, stable, rigid closed-form loop conformation. Here, we characterize the LacI-9C14 loop by SM-FRET as a function of inducer isopropyl-?,D-thiogalactoside (IPTG) concentration. Energy transfer measurements reveal partial but incomplete destabilization of loop formation by IPTG. Surprisingly, there is no change in the energy transfer efficiency of the remaining looped population. Models for the regulation of the lac operon often assume complete disruption of LacI-operator complexes upon inducer binding to LacI. Our work shows that even at saturating IPTG there is still a significant population of LacI-DNA complexes in a looped state, in accord with previous in vivo experiments that show incomplete induction (with J. Maher). Finally, we will report progress on characterizing the ``energy landscape'' for DNA looping upon systematic variation of the DNA linkers between the operators and the bending locus. Rod mechanics simulations (with N. Perkins) provide testable predictions on loop stability, topology, and FRET.

Kahn, Jason

2009-03-01

115

Implementation of optimum solar electricity generating system  

NASA Astrophysics Data System (ADS)

Under the 10th Malaysian Plan, the government is expecting the renewable energy to contribute approximately 5.5% to the total electricity generation by the year 2015, which amounts to 98MW. One of the initiatives to ensure that the target is achievable was to establish the Sustainable Energy Development Authority of Malaysia. SEDA is given the authority to administer and manage the implementation of the feed-in tariff (FiT) mechanism which is mandated under the Renewable Energy Act 2011. The move to establish SEDA is commendable and the FiT seems to be attractive but there is a need to create awareness on the implementation of the solar electricity generating system (SEGS). In Malaysia, harnessing technologies related to solar energy resources have great potential for implementation. However, the main issue that plagues the implementation of SEGS is the intermittent nature of this source of energy. The availability of sunlight is during the day time, and there is a need for electrical energy storage system, so that there is electricity available during the night time as well. The meteorological condition such as clouds, haze and pollution affects the SEGS as well. The PV based SEGS is seems to be promising electricity generating system that can contribute towards achieving the 5.5% target and will be able to minimize the negative effects of utilizing fossil fuels for electricity generation on the environment. Malaysia is committed to Kyoto Protocol, which emphasizes on fighting global warming by achieving stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. In this paper, the technical aspects of the implementation of optimum SEGS is discussed, especially pertaining to the positioning of the PV panels.

Singh, Balbir Singh Mahinder; Sivapalan, Subarna; Najib, Nurul Syafiqah Mohd; Menon, Pradeep; Karim, Samsul Ariffin A.

2014-10-01

116

A GIS-based shape index for land parcels  

NASA Astrophysics Data System (ADS)

Shape analysis is of interest in many fields of spatial science and planning including land management in rural areas. In particular, evaluating the shape of existing land parcels is critical when implementing rural development schemes such as land consolidation. However, existing land parcel shape indices have major deficiencies: completely different shapes of parcels may have the same index value or similar parcel shapes may have different index scores. Thus, there is a clear requirement for a more accurate and reliable measurement method. This paper therefore presents a new parcel shape index (PSI) which integrates a geographical information system (GIS) with a multi-attribute decision-making (MADM) method. It involves the amalgamated outcome of six geometric measures represented by value functions involving a mathematical representation of judgements by experts that compare each geometric measure with that of an optimum parcel shape defined for land consolidation projects. The optimum shape has a PSI value of 1 while the worst shape has a value close to 0. The shape measures used in the model include length of sides, acute angles, reflex angles, boundary points, compactness and regularity. The paper uses data for two case study areas in Cyprus to demonstrate the superiority of the new PSI over three existing shape indices employed in other studies. The methodology utilized here can be implemented in other disciplines dealing with the assessment of objects that can be compared to an optimum.

Demetriou, Demetris; Stillwell, John; See, Linda

2013-08-01

117

Optimum rotationally symmetric shells for flywheel rotors  

DOEpatents

A flywheel rim support formed from two shell halves. Each of the shell halves has a disc connected to the central shaft. A first shell element connects to the disc at an interface. A second shell element connects to the first shell element. The second shell element has a plurality of meridional slits. A cylindrical shell element connects to the second shell element. The cylindrical shell element connects to the inner surface of the flywheel rim. A flywheel rim support having a disc connected an outer diameter of a shaft. Two optimally shaped shell elements connect to the optimally shaped disc at an interface. The interface defines a discontinuity in a meridional slope of said support. A cylindrical shell element connects to the two shell elements. The cylindrical shell element has an outer surface for connecting to the inner surface of the flywheel rim. A flywheel rim casing includes an annular shell connected to the central shaft. The annular shell connects to the flywheel rim. A composite shell surrounds the shaft, annular shell and flywheel rim.

Blake, Henry W. (Oak Ridge, TN)

2000-01-01

118

Quark loop calculations  

NASA Astrophysics Data System (ADS)

Quark loop effects are studied with the stochastic matrix inversion algorithm. Z2 microcanonical noise is introduced to study the deviation from the orthonormality condition for finite configurations and compare with other noises. The results of the quark loops for various currents on a 16 3 × 24 lattice at ? = 6.0 with Wilson fermion ( ? = .148) are obtained for the Z2microcanonical noise. The results on the quark condensate, the topological susceptibility are given. We also discuss the feasibility for the two-point and three-point function calculations.

Dong, Shao-Jing; Liu, Keh-Fei

119

Closed-loop operation with alternative dewatering technology  

SciTech Connect

The introduction of dewatering devices for closed-loop drilling-fluid circulating systems and reserve pits is derived from technology that has been used in the industrial- and sanitary-waste treatment industries for years. This paper describes an overview of the need for closed-loop systems and provides the optimum design layout, including the fit of a dewatering device, for a drilling location. The introduction of a nonconventional dewatering device, called a screw press/thickener, is reviewed. A case history describing use of this technology in a southern Louisiana inland-marsh-area well is analyzed for the technical and economic viability of operating in a closed-loop mode. Results from this effort include a viable alternative to hauling off waste fluids from drilling sites and the realization that use of this technology can be justified economically.

Halliday, W.S.; Bray, R.P.; Youens, J.W.

1993-03-01

120

Optimum aerodynamic design via boundary control  

NASA Technical Reports Server (NTRS)

These lectures describe the implementation of optimization techniques based on control theory for airfoil and wing design. In previous studies it was shown that control theory could be used to devise an effective optimization procedure for two-dimensional profiles in which the shape is determined by a conformal transformation from a unit circle, and the control is the mapping function. Recently the method has been implemented in an alternative formulation which does not depend on conformal mapping, so that it can more easily be extended to treat general configurations. The method has also been extended to treat the Euler equations, and results are presented for both two and three dimensional cases, including the optimization of a swept wing.

Jameson, Antony

1994-01-01

121

Temporal Resolution [Loop Search  

E-print Network

perform the following steps. 1. Transform A into SNF, giving a set of clauses AS. 2. Perform step Logic [TEMPORAL RESOLUTION: LOOP SEARCH] ­ p.2/24 #12;Merged SNF To apply the temporal resolution rule, it is often convenient to combine one or more step clauses. Consequently, a variant on SNF called merged-SNF

Fisher, Michael

122

In the Loop  

ERIC Educational Resources Information Center

In the mid-1800s, Englishman John Venn invented a type of diagram to help visualize logical relationships. A Venn diagram is simply a rectangular box with circular loops in it that overlap to show how objects are related. This article describes activities with Venn diagrams that can be a fun way to sharpen students' logic skills and develop number…

Naylor, Michael

2006-01-01

123

Closing the Assessment Loop  

ERIC Educational Resources Information Center

Accreditors, speakers at assessment conferences, and campus leaders all decry the fact that too few faculty are closing the loop--that is, studying assessment findings to see what improvements might be suggested and taking the appropriate steps to make them. This is difficult enough with locally developed measures; adding the need to interpret…

Banta, Trudy W.; Blaich, Charles

2011-01-01

124

NETL - Chemical Looping Reactor  

SciTech Connect

NETL's Chemical Looping Reactor unit is a high-temperature integrated CLC process with extensive instrumentation to improve computational simulations. A non-reacting test unit is also used to study solids flow at ambient temperature. The CLR unit circulates approximately 1,000 pounds per hour at temperatures around 1,800 degrees Fahrenheit.

None

2013-07-24

125

NETL - Chemical Looping Reactor  

ScienceCinema

NETL's Chemical Looping Reactor unit is a high-temperature integrated CLC process with extensive instrumentation to improve computational simulations. A non-reacting test unit is also used to study solids flow at ambient temperature. The CLR unit circulates approximately 1,000 pounds per hour at temperatures around 1,800 degrees Fahrenheit.

None

2014-06-26

126

Closing the Loop Sampler.  

ERIC Educational Resources Information Center

Closing the Loop (CTL) is a science curriculum designed to introduce students to integrated waste management through awareness. This document presents five lesson plans focusing on developing an understanding of natural resources, solid wastes, conservation, and the life of landfills. Contents include: (1) "What Are Natural Resources?"; (2)…

California Integrated Waste Management Board, Sacramento.

127

Automatic loop interchange  

Microsoft Academic Search

Parallel and vector machines are becoming increasingly important to many computation intensive applications. Effectively utilizing such architectures, particularly from sequential languages such as Fortran, has demanded increasingly sophisticated compilers. In general, a compiler needs to significantly reorder a program in order to generate code optimal for a specific architecture.Because DO loops typically control the execution of a number of statements,

John R. Allen; Ken Kennedy

1984-01-01

128

Fine Structures and Overlying Loops of Confined Solar Flares  

NASA Astrophysics Data System (ADS)

Using the H? observations from the New Vacuum Solar Telescope at the Fuxian Solar Observatory, we focus on the fine structures of three confined flares and the issue why all the three flares are confined instead of eruptive. All the three confined flares take place successively at the same location and have similar morphologies, so can be termed homologous confined flares. In the simultaneous images obtained by the Solar Dynamics Observatory, many large-scale coronal loops above the confined flares are clearly observed in multi-wavelengths. At the pre-flare stage, two dipoles emerge near the negative sunspot, and the dipolar patches are connected by small loops appearing as arch-shaped H? fibrils. There exists a reconnection between the small loops, and thus the H? fibrils change their configuration. The reconnection also occurs between a set of emerging H? fibrils and a set of pre-existing large loops, which are rooted in the negative sunspot, a nearby positive patch, and some remote positive faculae, forming a typical three-legged structure. During the flare processes, the overlying loops, some of which are tracked by activated dark materials, do not break out. These direct observations may illustrate the physical mechanism of confined flares, i.e., magnetic reconnection between the emerging loops and the pre-existing loops triggers flares and the overlying loops prevent the flares from being eruptive.

Yang, Shuhong; Zhang, Jun; Xiang, Yongyuan

2014-10-01

129

Effect of Relative Humidity on the Optimum Flute Shape for Corrugated Fiberboard  

Microsoft Academic Search

Container stacking strength is an important performance requirement of corrugated fiberboard. The objective of this study is to examine theoretically how fluting geometry affects fiberboard strength and stiffness under standard relative humidity (RH) and high RH conditions. The fluted medium in a corrugated fiberboard is modeled as a connection of curved arc and straight flank segments passing through the middle

Thomas J. Urbanik

130

A note on the optimum quantity of money  

Microsoft Academic Search

In a model where agents use money to offset uninsurable idiosyncratic income fluctuation, Bewley (1983) has shown that it may be impossible to satiate the demand for money as recommended by the literature on the optimum quantity of money (Friedman, 1969). This note shows, by means of an example, that even when it is possible to implement the traditional optimum

Perry Mehrling

1995-01-01

131

Optimum Signal Detector in Non-white Noise  

Microsoft Academic Search

The MF (matched filter) is the optimum detector in white noise since it can maximize the output SNR (signal to noise ratio). However, the MF cannot maximize SNR if the noise is not white. So the optimum signal detector in non-white noise environment is proposed and its performance is analyzed in this paper. As a result, the proposed detector shows

Seog Kun Yu; Woo Tae Kim; Eon Kyeong Joo

2006-01-01

132

Optimum academic performance and its relation to emotional intelligence  

Microsoft Academic Search

In Emotional Intelligence, Daniel Goleman (1995) discusses the effect of emotional competence on optimum performance. He describes the state of flow in which optimum performance occurs. Literature from coaching sports talks about this state of total concentration, as well. Our goal as teachers is to provide an atmosphere where flow occurs easily and the students are totally engaged in learning.

Richard Culver; Charles Yokomoto

1999-01-01

133

Method for determining optimum thickness of insulation for buildings  

Microsoft Academic Search

Two examples are followed to show a method to calculate optimum R value for a wall or other thermal barrier. The optimum thickness of fiberglass insulation is calculated in two cases in which heating oil prices remain constant in one case and increases in the other. Each cost element of the problem is expressed in terms of dollars and related

1978-01-01

134

Active aeroelastic panels with optimum self-straining actuators  

NASA Astrophysics Data System (ADS)

The objective of this research is to examine the ability of self-straining actuators to create panel deflections and their effect on panel flutter speed. Two configurations of piezoelectric actuators were used to create deflections by bonding them to one surface of an aerodynamic panel: a rectangular patch and discrete grid stiffeners. A Rayleigh-Ritz program was developed to analyze the static deflection, free vibration, flutter behavior, and deflection under airloads of the panel for both actuator configurations. A formal optimization of the patch actuator to produce maximum panel deflection was performed for aluminum and steel host panels with simply supported and clamped boundary conditions and several different aspect ratios. It was found that by allowing the actuator to have two independent layers (but still single-sided), slightly more deflection could be produced than with a single layer actuator. Stiffener configurations were studied with varying numbers, cross section size and shape, and orientations that were parallel to the x-axis, parallel to the y-axis, and parallel to both axes. It was found that no optimum combination of stiffener parameters existed to produce the maximum deflection in a panel, unlike the patch actuators. For low numbers of stifferners, a rectangular cross section and placing them parallel to the y-axis produced the most deflection. Placing the stiffeners parallel to the x-axis, or in the flow direction, was the most beneficial for increasing the flutter dynamic pressure for the panel. The rectangular stiffener cross section increased the dynamic pressure more than the square cross section. Different patch actuator sizes, panel locations, and activation levels were examined for their effect on flutter dynamic pressure. Although the patch was always able to increase the flutter dynamic pressure, the amount of the increase was very dependent on patch size, location, and activation level.

Leeks, Tamara Jill Vaughen

135

The gluon beam function at two loops  

NASA Astrophysics Data System (ADS)

The virtuality-dependent beam function is a universal ingredient in the resummation for observables probing the virtuality of incoming partons, including N -jettiness and beam thrust. We compute the gluon beam function at two-loop order. Together with our previous results for the two-loop quark beam function, this completes the full set of virtuality-dependent beam functions at next-to-next-to-leading order (NNLO). Our results are required to account for all collinear initial-state radiation effects on the N -jettiness event shape through N3LL order. We present numerical results for both the quark and gluon beam functions up to NNLO and N3LL order. Numerically, the NNLO matching corrections are important. They reduce the residual matching scale dependence in the resummed beam function by about a factor of two.

Gaunt, Jonathan R.; Stahlhofen, Maximilian; Tackmann, Frank J.

2014-08-01

136

COLD TEST LOOP INTEGRATED TEST LOOP RESULTS  

SciTech Connect

A testing facility (Cold Test Loop) was constructed and operated to demonstrate the efficacy of the Accelerated Waste Retrieval (AWR) Project's planned sluicing approach to the remediation of Silos 1 and 2 at the Fernald Environmental Management Project near Cincinnati, Ohio. The two silos contain almost 10,000 tons of radium-bearing low-level waste, which consists primarily of solids of raffinates from processing performed on ores from the Democratic Republic of Congo (commonly referred to as ''Belgium Congo ores'') for the recovery of uranium. These silos are 80 ft in diameter, 36 ft high to the center of the dome, and 26.75 ft to the top of the vertical side walls. The test facility contained two test systems, each designed for a specific purpose. The first system, the Integrated Test Loop (ITL), a near-full-scale plant including the actual equipment to be installed at the Fernald Site, was designed to demonstrate the sluicing operation and confirm the selection of a slurry pump, the optimal sluicing nozzle operation, and the preliminary design material balance. The second system, the Component Test Loop (CTL), was designed to evaluate many of the key individual components of the waste retrieval system over an extended run. The major results of the initial testing performed during July and August 2002 confirmed that the AWR approach to sluicing was feasible. The ITL testing confirmed the following: (1) The selected slurry pump (Hazleton 3-20 type SHW) performed well and is suitable for AWR application. However, the pump's motor should be upgraded to a 200-hp model and be driven by a 150-hp variable-frequency drive (VFD). A 200-hp VFD is not much more expensive and would allow the pump to operate at full speed. (2) The best nozzle performance was achieved by using 15/16-in. nozzles operated alternately. This configuration appeared to most effectively mine the surrogate. (3) The Solartron densitometer, which was tested as an alternative mass flow measurement device, did not operate effectively. Consequently, it is not suitable for application to the AWR process. (4) Initially, the spray ring (operated at approximately 2300 psi) and the nozzles provided by the pump vendor did not perform acceptably. The nozzles were replaced with a more robust model, and the performance was then acceptable. (5) The average solids concentration achieved in the slurry before Bentogrout addition was approximately 16% by weight. The solids concentration of the slurry after Bentogrout addition ranged from 26% to approximately 40%. The slurry pump and ITL system performed well at every concentration. No line plugging or other problems were noted. The results of the CTL runs and later ITL testing are summarized in an appendix to this report.

Abraham, TJ

2003-10-22

137

Learning Active Shape Models for Bifurcating Contours  

Microsoft Academic Search

Statistical shape models are often learned from examples based on landmark correspondences between annotated examples. A method is proposed for learning such models from contours with inconsistent bifurcations and loops. Automatic segmentation of tibial and femoral contours in knee x-ray images is investigated as a step towards reliable, quantitative radio- graphic analysis of osteoarthritis for diagnosis and assessment of progression.

Matthias Seise; Stephen J. Mckenna; Ian W. Ricketts; Carlos A. Wigderowitz

2007-01-01

138

Effect of Loop Geometry on TEM Response Over Layered Earth  

NASA Astrophysics Data System (ADS)

A large horizontal loop located on the ground or carried by an aircraft are the most common sources of the transient electromagnetic method. Although topographical factors or airplane outlines make the loop of arbitrary shape, magnetic sources are generally represented as a magnetic dipole or a circular loop, which may bring about significant errors in the calculated response. In this paper, we present a method for calculating the response of a loop of arbitrary shape (for which the description can be obtained by different methods, including GPS localization) in air or on the surface of a stratified earth. The principle of reciprocity is firstly used to exchange the functions of the transmitting loop and the dipole receiver, then the response of a vertical or a horizontal magnetic dipole is calculated beforehand, and finally the line integral of the second kind is employed to get the transient response. Analytical analysis and comparisons depict that our work got very good results in many situations. Synthetic and field examples are given in the end to show the effect of loop geometry and how our method improves the precision of the EM response.

Qi, Youzheng; Huang, Ling; Wu, Xin; Fang, Guangyou; Yu, Gang

2014-09-01

139

Modeling a Hot Wheels Loop  

NSDL National Science Digital Library

In this activity a Tracker model is compared with a toy truck attempting to drive up and around a Hot Wheels vertical loop track. Three different videos show the truck entering the loop at different speeds. For related EJS models see Particle Motion On A Curve and Particle Motion On A Vertical Elliptical Loop. The zip file includes all three videos and pdf instructions.

Brown, Douglas

2012-01-31

140

The Cinderella Loop Project  

NASA Astrophysics Data System (ADS)

On 1999 Nov 6 at 02:30 UT, a solar loop (dubbed Cinderella) on the northeast limb was simultaneously observed by TRACE, EIT on SOHO, and SXT on Yohkoh. This project investigates differences among the data sets from the three instruments. For example, EIT and TRACE have nearly identical temperature responses, but does the high resolution TRACE imager (0.5 arcsec pixels) produce results that match those from the lower resolution EIT imager (2.6 arcsec pixels)? Furthermore, EIT and SXT have similar spatial resolutions, but their temperature responses are much farther apart. Do these two instruments observe the same structures within the loop, and if so, how do their temperature and emissions measures compare? What are the effects of background subtraction on all three data sets? This presentation will address these questions. Solar physics research at the University of Memphis is supported by NASA grants NAG5-9783 and NAG5-12096.

O'Connor, J.; Coyle, T.; Douglass, J.; Schmelz, J. T.

2004-05-01

141

The FALC-Loop web server for protein loop modeling  

PubMed Central

The FALC-Loop web server provides an online interface for protein loop modeling by employing an ab initio loop modeling method called FALC (fragment assembly and analytical loop closure). The server may be used to construct loop regions in homology modeling, to refine unreliable loop regions in experimental structures or to model segments of designed sequences. The FALC method is computationally less expensive than typical ab initio methods because the conformational search space is effectively reduced by the use of fragments derived from a structure database. The analytical loop closure algorithm allows efficient search for loop conformations that fit into the protein framework starting from the fragment-assembled structures. The FALC method shows prediction accuracy comparable to other state-of-the-art loop modeling methods. Top-ranked model structures can be visualized on the web server, and an ensemble of loop structures can be downloaded for further analysis. The web server can be freely accessed at http://falc-loop.seoklab.org/. PMID:21576220

Ko, Junsu; Lee, Dongseon; Park, Hahnbeom; Coutsias, Evangelos A.; Lee, Julian; Seok, Chaok

2011-01-01

142

Cosmic string loop microlensing  

NASA Astrophysics Data System (ADS)

Cosmic superstring loops within the galaxy microlens background point sources lying close to the observer-string line of sight. For suitable alignments, multiple paths coexist and the (achromatic) flux enhancement is a factor of two. We explore this unique type of lensing by numerically solving for geodesics that extend from source to observer as they pass near an oscillating string. We characterize the duration of the flux doubling and the scale of the image splitting. We probe and confirm the existence of a variety of fundamental effects predicted from previous analyses of the static infinite straight string: the deficit angle, the Kaiser-Stebbins effect, and the scale of the impact parameter required to produce microlensing. Our quantitative results for dynamical loops vary by O(1) factors with respect to estimates based on infinite straight strings for a given impact parameter. A number of new features are identified in the computed microlensing solutions. Our results suggest that optical microlensing can offer a new and potentially powerful methodology for searches for superstring loop relics of the inflationary era.

Bloomfield, Jolyon K.; Chernoff, David F.

2014-06-01

143

Optical Coherence Tomography as a Tool for Measuring Morphogenetic Deformation of the Looping Heart  

Microsoft Academic Search

Optical coherence tomography (OCT) was used to investigate mor- phogenesis of the embryonic chick heart during the first phase of looping (c-looping), as the heart bends and twists into a c-shaped tube. The pres- ent study focuses on the morphomechanical effects of the splanchnopleure (SPL), a membrane that has been shown to play a major role in cardiac torsion by

Benjamen A. Filas; Igor R. Efimov; Larry A. Taber

2007-01-01

144

Elastic Rod Model of a DNA Loop in the Lac Operon  

NASA Astrophysics Data System (ADS)

We use the theory of elasticity to compute the shape of the DNA loop bridging the gap in the crystal structure of the lac repressor-DNA complex. The Kirchhoff system of equations with boundary conditions derived from the crystal structure is solved using a continuation method. This approach can be applied effectively to find coarse-grained conformational minima of DNA loops.

Balaeff, Alexander; Mahadevan, L.; Schulten, Klaus

1999-12-01

145

Determination of optimum vibroisolation systems for a sitting human operator.  

PubMed

Optimum vibroisolation systems were obtained for a sitting human operator subjected to stochastic vertical vibrations. Is was concluded that there exists a physically realizable optimum function phi(s), which describes the desired fibroisolation system (s = iomega). The theory for finding an optimum vibroisolation system was developed on the basis of a specific a priori criterion, and assuming, for input, random, ergodic vibrations given by power spectral densities of accelerations of the vibration base. Examples are given for human body models consisting of a mass, a linear or nonlinear spring, and a damper. PMID:623592

Ksiazek, M

1978-01-01

146

A comparison of methods for DPLL loop filter design  

NASA Technical Reports Server (NTRS)

Four design methodologies for loop filters for a class of digital phase-locked loops (DPLLs) are presented. The first design maps an optimum analog filter into the digital domain; the second approach designs a filter that minimizes in discrete time weighted combination of the variance of the phase error due to noise and the sum square of the deterministic phase error component; the third method uses Kalman filter estimation theory to design a filter composed of a least squares fading memory estimator and a predictor. The last design relies on classical theory, including rules for the design of compensators. Linear analysis is used throughout the article to compare different designs, and includes stability, steady state performance and transient behavior of the loops. Design methodology is not critical when the loop update rate can be made high relative to loop bandwidth, as the performance approaches that of continuous time. For low update rates, however, the miminization method is significantly superior to the other methods.

Aguirre, S.; Hurd, W. J.; Kumar, R.; Statman, J.

1986-01-01

147

Characterization and indirect control of solids transfer loops  

SciTech Connect

A cold-flow, circulating fluid bed unit has been operated to test advanced control strategies. The riser is one foot diameter and 50 foot tall and consists of metal and acrylic spool pieces for mechanical support and visual observation. The unit was run with 10--20 ft/s in the riser at ambient pressure using 250 micron polyvinyl chloride particle. The hydrodynamics of each component leg in the Circulating Fluid Bed (CFB) must be characterized to facilitate control of the integrated circulating loop. The CFB is composed of the transport riser lift line, cyclone particle gas separator, dense bed downcomer or standpipe, and non-mechanical valve to recycle solids to the riser. The primary control elements of a fluid bed are located in the fluidizing gas streams. The processes of solids transfer through each leg result in highly non-linear, coupled process variables. Dynamic simulations suggest hydrodynamic mechanisms to be experimentally characterized. Both open-loop and closed loop control analysis techniques are demonstrated which characterize both the component, as well as the integrated loop. The process variables are defined and their dependencies are characterized. Experimental and analytical techniques for exhibiting these dependencies within each component are illustrated. Control techniques for uncoupling process variables around the loop are demonstrated. Adaptive control techniques are proposed to assure robust, optimum performance.

Lawson, L.O.; Shadle, L.J.

1999-07-01

148

The Role of Entropic Effects on DNA Loop Formation  

NASA Astrophysics Data System (ADS)

The formation of protein mediated DNA loops often regulates gene expression. Typically, a protein is simultaneously bound to two DNA operator sites. An example is the lactose repressor which binds to the Lac operon of E. coli. We characterize the mechanics of this system by calculating the free energy cost of loop formation. We construct a Hamiltonian that describes the change in DNA bending energy due to linear perturbations about the looped and open states, starting from a non-linear mechanical rod model that determines the shape and bending energy of the inter-operator DNA loop while capturing the intrinsic curvature and sequence-dependent elasticity of the DNA. The crystal structure of the LacI protein provides the boundary conditions for the DNA. We then calculate normal modes of the open and closed loops to account for the thermal fluctuations. The ratio of determinants of the two Hamiltonians yields the partition function, and the enthalphic and entropic cost of looping. This calculation goes beyond standard elastic energy models because it fully accounts for the substantial entropic differences between the two states. It also includes effects of sequence dependent curvature and stiffness and allows anisotropic variations in persistence length. From the free energy we then calculate the J-factor and ratio of loop lifetimes.

Wilson, David; Tkachenko, Alexei; Lillian, Todd; Perkins, Noel; Meiners, Jens Christian

2009-03-01

149

A Generalized Theory of DNA Looping and Cyclization  

NASA Astrophysics Data System (ADS)

We have developed a semi-analytic method for calculating the Stockmayer Jacobson J-factor for protein mediated DNA loops. The formation of DNA loops on the order of a few persistence lengths is a key component in many biological regulatory functions. The binding of LacI protein within the Lac Operon of E.coli serves as the canonical example for loop regulated transcription. We use a non-linear rod model to determine the equilibrium shape of the inter-operator DNA loop under prescribed binding constraints while taking sequence-dependent curvature and elasticity into account. Then we construct a Hamiltonian that describes thermal fluctuations about the open and looped equilibrium states, yielding the entropic and enthalpic costs of loop formation. Our work demonstrates that even for short sequences of the order one persistence length, entropic terms contribute substantially to the J factor. We also show that entropic considerations are able to determine the most favorable binding topology. The J factor can be used to compare the relative loop lifetimes of various DNA sequences, making it a useful tool in sequence design. A corollary of this work is the computation of an effective torsional persistence length, which demonstrates how torsion bending coupling in a constrained geometry affects the conversion of writhe to twist.

Wilson, David; Lillian, Todd; Perkins, Noel; Tkachenko, Alexei; Meiners, Jens-Christian

2010-03-01

150

Piezoactuator Design Considering the Optimum Placement of FGM Piezoelectric Material  

E-print Network

Piezoactuator Design Considering the Optimum Placement of FGM Piezoelectric Material Ronny C has been explored in piezoelectric materials to improve properties and to increase the lifetime of piezoelectric actuators. Elastic, piezoelectric, and dielectric properties are graded along the thickness

Paulino, Glaucio H.

151

Controller architectures for optimum performance in practical active acoustic metamaterials  

E-print Network

Controller architectures for optimum performance in practical active acoustic metamaterials M in the design and production of acoustic metamaterials with physical qualities not seen in naturally occurring of the research into active acoustic metamaterials remains theoretical, therefore to determine whether

Boyer, Edmond

152

50 CFR 648.20 - Maximum optimum yield (OYs).  

Code of Federal Regulations, 2010 CFR

...ADMINISTRATION, DEPARTMENT OF COMMERCE FISHERIES OF THE NORTHEASTERN UNITED STATES Management Measures for the Atlantic Mackerel, Squid, and Butterfish Fisheries § 648.20 Maximum optimum yield (OYs). The OYs specified pursuant to § 648.21...

2010-10-01

153

Optimum testing of multiple hypotheses in quantum detection theory  

NASA Technical Reports Server (NTRS)

The problem of specifying the optimum quantum detector in multiple hypotheses testing is considered for application to optical communications. The quantum digital detection problem is formulated as a linear programming problem on an infinite-dimensional space. A necessary and sufficient condition is derived by the application of a general duality theorem specifying the optimum detector in terms of a set of linear operator equations and inequalities. Existence of the optimum quantum detector is also established. The optimality of commuting detection operators is discussed in some examples. The structure and performance of the optimal receiver are derived for the quantum detection of narrow-band coherent orthogonal and simplex signals. It is shown that modal photon counting is asymptotically optimum in the limit of a large signaling alphabet and that the capacity goes to infinity in the absence of a bandwidth limitation.

Yuen, H. P.; Kennedy, R. S.; Lax, M.

1975-01-01

154

Equivalent Electric Circuit Models of Coronal Magnetic Loops and Related Oscillatory Phenomena on the Sun  

NASA Astrophysics Data System (ADS)

Coronal loops, which trace closed magnetic field lines, are the primary structural elements of the solar atmosphere. Complex dynamics of solar coronal magnetic loops, together with action of possible subphotospheric dynamo mechanisms, turn the majority of the coronal loops into current-carrying structures. In that connection none of the loops can be considered as isolated from the surroundings. The current-carrying loops moving relative to each other interact via the magnetic field and currents. One of the ways to take into account this interaction consists in application of the equivalent electric circuit models of coronal loops. According to these models, each loop is considered as an equivalent electric LCR-circuit with variable inductive coefficients L, capacitance C, and resistance R, which depend on shape, scale, position of the loop with respect to neighbouring loops, as well as on the plasma parameters in the magnetic tube. Such an approach enables to describe the process of electric current dynamics in the groups of coronal loops, as well as the related dynamical, energy release and radiation processes. In the present paper we describe the major principles of LCR-circuit models of coronal magnetic loops, and show their application for interpretation of the observed oscillatory phenomena in the loops and in the related radiation.

Khodachenko, Maxim L.; Zaitsev, Valerii V.; Kislyakov, Albert G.; Stepanov, Alexander V.

2009-12-01

155

Using acausal shaping techniques to reduce robot vibration  

Microsoft Academic Search

A method for generating shaped command inputs which reduce endpoint vibration is presented. The technique applies to both open- and closed-loop systems. The Draper Laboratory's Space Shuttle remote manipulator system nonlinear simulator is used to verify the substantial reduction of residual vibration. In addition, the shaped inputs have been designed to closely approximate the time-optimal input, therefore only a small

Neil C. Singer; Warren P. Seering

1988-01-01

156

Variable structure control of shape memory alloy actuators  

Microsoft Academic Search

A shape memory alloy (SMA) actuator consisting of a number of thin NiTi fibers woven in a counter rotating helical pattern around supporting disks is first described. This structure accomplishes a highly efficient transformation between force and displacement overcoming the main mechanical drawback of shape memory alloys, that being limited strain. Time domain open loop experiments were then conducted to

D. Grant; V. Hayward

1997-01-01

157

Optimum simple step-stress accelerated life tests with censoring  

Microsoft Academic Search

The authors present the optimum simple time-step and failure-step stress accelerated life tests for the case where a prespecified censoring time is involved. An exponential life distribution with a mean that is a log-linear function of stress, and a cumulative exposure model are assumed. The authors obtain the optimum test plans to minimize the asymptotic variance of the maximum-likelihood estimator

D. S. Bai; M. S. Kim; S. H. Lee

1989-01-01

158

The optimum grain size for minimizing energy losses in iron  

NASA Astrophysics Data System (ADS)

A model able to predict the optimum grain size for textured electrical steels used in motors or transformers is presented. The model is based on the Pry and Bean model for the anomalous losses. The validity of the model is restricted to the frequency range of 1-1000 Hz. The model predicts that the optimum grain size decreases as: resistivity decreases or frequency increases or thickness of steel sheet increases. The predictions of the model are compared with experimental results.

de Campos, M. F.; Teixeira, J. C.; Landgraf, F. J. G.

2006-06-01

159

Optimum receiver structures for phase-multiplexed modulations  

NASA Technical Reports Server (NTRS)

A MAP (maximum a posteriori) estimation loop is derived for a QPSK signal and, by suitable approximation to the nonlinearity which arises as a consequence of the MAP theory, is reconfigured with practical realizations that are valid for high and low SNRs. In particular, it is shown that by approximating the hyperbolic tangent nonlinearity in the MAP estimation loop by the first two terms in its power series, an interesting practical realization of this loop results which applies at low SNRs. The error signal in this loop is formed by multiplying the error signal and lock detector output signal of a conventional biphase Costas loop. A generalized linear in-phase channel configuration is proposed which allows carrier reconstruction from an unbalanced QPSK signal at all ratios of data rates and powers in the two channels, even in the limit as these ratios simultaneously approach unity, i.e., balanced quadriphase.

Simon, M. K.

1978-01-01

160

Coupled dual loop absorption heat pump  

DOEpatents

A coupled dual loop absorption system which utilizes two separate complete loops. Each individual loop operates at three temperatures and two pressures. This low temperature loop absorber and condenser are thermally coupled to the high temperature loop evaporator, and the high temperature loop condenser and absorber are thermally coupled to the low temperature generator.

Sarkisian, Paul H. (Watertown, MA); Reimann, Robert C. (Lafayette, NY); Biermann, Wendell J. (Fayetteville, NY)

1985-01-01

161

Comparison of hysteresis loop area scaling behavior of Co/Pt multilayers: Discrete and continuous field sweeping  

NASA Astrophysics Data System (ADS)

We have investigated the hysteresis loop shape changes with discrete and continuous magnetic field sweeping for Co/Pt multilayers with a perpendicular magnetic anisotropy. The hysteresis loop shape was observed by measuring a polar magneto-optical Kerr effect. The loop area has been found to increase rapidly with an increase of the field step size as well as the sweeping frequency until the area reaches a maximum. The increase of the loop area has been analyzed based on the Steinmetz law, where a loop area scaling exponent determined from discrete field sweeping is compared to a scaling exponent from continuous field sweeping. The dynamic coercivity behavior with respect to discrete and continuous field sweeping is analyzed together with the loop area scaling behavior, suggesting that details of magnetic configuration disorders do not modify the loop area scaling exponent.

Handoko, Djati; Lee, Sang-Hyuk; Min Lee, Kyung; Jeong, Jong-Ryul; Kim, Dong-Hyun

2014-02-01

162

Sigmoid-to-flux-rope Transition Leading to a Loop-like Coronal Mass Ejection  

NASA Astrophysics Data System (ADS)

Sigmoids are one of the most important precursor structures for solar eruptions. In this Letter, we study a sigmoid eruption on 2010 August 1 with EUV data obtained by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO). In AIA 94 Å (Fe XVIII; 6 MK), topological reconfiguration due to tether-cutting reconnection is unambiguously observed for the first time, i.e., two opposite J-shaped loops reconnect to form a continuous S-shaped loop, whose central portion is dipped and aligned along the magnetic polarity inversion line (PIL), and a compact loop crossing the PIL. A causal relationship between photospheric flows and coronal tether-cutting reconnections is evidenced by the detection of persistent converging flows toward the PIL using line-of-sight magnetograms obtained by the Helioseismic and Magnetic Imager on board SDO. The S-shaped loop remains in quasi-equilibrium in the lower corona for about 50 minutes, with the central dipped portion rising slowly at ~10 km s-1. The speed then increases to ~60 km s-1 about 10 minutes prior to the onset of a GOES-class C3.2 flare, as the S-shaped loop speeds up its transformation into an arch-shaped loop, which eventually leads to a loop-like coronal mass ejection. The AIA observations combined with H? filtergrams as well as hard X-ray imaging and spectroscopy are consistent with most flare loops being formed by reconnection of the stretched legs of less-sheared J-shaped loops that envelopes the rising flux rope, in agreement with the standard tether-cutting scenario.

Liu, Rui; Liu, Chang; Wang, Shuo; Deng, Na; Wang, Haimin

2010-12-01

163

Solar flare gamma-ray line shapes  

NASA Technical Reports Server (NTRS)

A computer code has been developed which is used to calculate ab initio the laboratory shapes and energy shifts of gamma-ray lines from (C-12)(p, gamma/4.438/)p-prime(C-12) and (O-16)(p, gamma/6.129/)p-prime(O-16) reactions and to calculate the expected shapes of these lines from solar flares. The sensitivity of observable solar flare gamma-ray line shapes to the directionality of the incident particles is investigated for several projectile angular distributions. Shapes of the carbon and oxygen lines are calculated assuming realistic proton energy spectra for particles in circular orbits at the mirror points of magnetic loops, for particle beams directed downward into the photosphere, and for isotropic particle distributions. Line shapes for flare sites near the center of the sun and on the limb are shown for both thin-target and thick-target interaction models.

Werntz, C.; Kim, Y. E.; Lang, Frederick L.

1990-01-01

164

The double loop mattress suture.  

PubMed

An interrupted stitch type with favorable tissue characteristics will reduce local wound complications. We describe a novel high-strength, low-tension repair for the interrupted closure of skin, cartilage, and muscle, the double loop mattress stitch, and compare it experimentally with other interrupted closure methods. The performance of the double loop mattress technique in porcine cartilage and skeletal muscle is compared with the simple, mattress, and loop mattress interrupted sutures in both a novel porcine loading chamber and mechanical model. Wound apposition is assessed by electron microscopy. The performance of the double loop mattress in vivo was confirmed using a series of 805 pediatric laparotomies/laparoscopies. The double loop mattress suture is 3.5 times stronger than the loop mattress in muscle and 1.6 times stronger in cartilage (p???0.001). Additionally, the double loop mattress reduces tissue tension by 66% compared with just 53% for the loop mattress (p???0.001). Wound gapping is equal, and wound eversion appears significantly improved (p???0.001) compared with the loop mattress in vitro. In vivo, the double loop mattress performs as well as the loop mattress and significantly better than the mattress stitch in assessments of wound eversion and dehiscence. There were no episodes of stitch extrusion in our series of patients. The mechanical advantage of its intrinsic pulley arrangement gives the double loop mattress its favorable properties. Wound dehiscence is reduced because this stitch type is stronger and exerts less tension on the tissue than the mattress stitch. We advocate the use of this novel stitch wherever a high-strength, low-tension repair is required. These properties will enhance wound repair, and its application will be useful to surgeons of all disciplines. PMID:24698436

Biddlestone, John; Samuel, Madan; Creagh, Terry; Ahmad, Tariq

2014-01-01

165

Initial stages of misfit stress relaxation by rectangular prismatic dislocation loops in composite nanostructures  

NASA Astrophysics Data System (ADS)

Theoretical models are proposed for describing the initial stages of misfit stress relaxation in bulk and hollow core-shell nanoparticles and nanowires, and in planar bi- and trinanolayers through generation of rectangular prismatic dislocation loops at the inner and outer interfaces. We obtain the changes in the total energy of the system due to the appearance of dislocation loops and calculate the critical conditions of their formation. We also determine the most profitable shape of the loops and the preferred places of their generation. Finally, we choose the nanostructures which are the most stable against dislocation loop generation.

Gutkin, M. Yu; Smirnov, A. M.

2014-10-01

166

On the Role of Intrinsic and Extrinsic Forces in Early Cardiac S-looping  

PubMed Central

Background Looping is a crucial phase during heart development when the initially straight heart tube is transformed into a shape that more closely resembles the mature heart. Although the genetic and biochemical pathways of cardiac looping are well-studied, the biophysical mechanisms that actually effect the looping process remain poorly understood. Using a combined experimental (chick embryo) and computational (finite element modeling) approach, we study the forces driving early s-looping when the primitive ventricle moves to its definitive position inferior to the common atrium. Results New results from our study indicate that the primitive heart has no intrinsic ability to form an s-loop and that extrinsic forces are necessary to effect early s-looping. They support previous studies that established an important role for cervical flexure in causing early cardiac s-looping. Our results also show that forces applied by the splanchnopleure cannot be ignored during early s-looping and shed light on the role of cardiac jelly. Using available experimental data and computer modeling, we successfully developed and tested a hypothesis for the force mechanisms driving s-loop formation. Conclusions Forces external to the primitive heart tube are necessary in the later stages of cardiac looping. Experimental and model results support our proposed hypothesis for forces driving early s-looping. PMID:23553909

Ramasubramanian, Ashok; Chu-LaGraff, Quynh B.; Buma, Takashi; Chico, Kevin T.; Carnes, Meagan E.; Burnett, Kyra R.; Bradner, Sarah A.; Gordon, Shaun S.

2014-01-01

167

On the existence of small-amplitude optimum hydrofoil propulsion  

NASA Astrophysics Data System (ADS)

Sparenberg (1978) has considered the optimum thrust production by means of a flexible profile. Optimum thrust production implies the generation of a prescribed mean value of thrust at the cost of minimum energy. It was shown in the realm of a linear theory, that when suitable constraints were put on the motion of the profile, optimum motions exist. It could be proved that no optimum thrust producing swimming motion can be found, when only a constraint was put on the magnitude of the amplitude of the motion. The proof was primarily based on the construction of a minimizing sequence of motions, in which the wriggling of the profile increased indefinitely. The question arose in this connection if the number of constraints can be decreased if the profile is assumed to be rigid. In the current investigation this question is considered. It is shown that an optimum motion exists. It is also found that the constraints used in the earlier investigation are unnecessarily severe for the heaving motion.

Sparenberg, J. A.; Thomas, E. G. F.

168

Loop-the-Loop: Bringing Theory into Practice  

ERIC Educational Resources Information Center

During the Thai high-school physics teacher training programme, we used an aluminum loop-the-loop system built by the Institute for the Promotion of Teaching Science and Technology (IPST) to demonstrate a circular motion and investigate the concept of the conservation of mechanical energy. There were 27 high-school teachers from three provinces,…

Suwonjandee, N.; Asavapibhop, B.

2012-01-01

169

Phase-Locked Loops  

NSDL National Science Digital Library

Phase-locked loops (PLL) are unique feedback control circuits that offer many useful features and benefits in electronic applications. PLLs are available either in integrated circuit (IC) form for general applications or built into larger system IC chips. Today, PLLs are found in virtually all types of electronic equipment from PCs to consumer products like TV sets and cell phones. This module provides an introduction to the PLL and its applications. It begins with an overview of the main components of a PLL and how these components work together. It then describes PLL specifications and a description of the most widely used applications including frequency synthesizers, clock multipliers, clock and data recovery circuits, FM demodulators, and filters.

2012-09-06

170

Dynamic PID loop control  

SciTech Connect

The Horizontal Test Stand (HTS) SRF Cavity and Cryomodule 1 (CM1) of eight 9-cell, 1.3GHz SRF cavities are operating at Fermilab. For the cryogenic control system, how to hold liquid level constant in the cryostat by regulation of its Joule-Thompson JT-valve is very important after cryostat cool down to 2.0 K. The 72-cell cryostat liquid level response generally takes a long time delay after regulating its JT-valve; therefore, typical PID control loop should result in some cryostat parameter oscillations. This paper presents a type of PID parameter self-optimal and Time-Delay control method used to reduce cryogenic system parameters oscillation.

Pei, L.; Klebaner, A.; Theilacker, J.; Soyars, W.; Martinez, A.; Bossert, R.; DeGraff, B.; Darve, C.; /Fermilab

2011-06-01

171

Vortex loops and Majoranas  

SciTech Connect

We investigate the role that vortex loops play in characterizing eigenstates of interacting Majoranas. We give some general results and then focus on ladder Hamiltonian examples as a test of further ideas. Two methods yield exact results: (i) A mapping of certain spin Hamiltonians to quartic interactions of Majoranas shows that the spectra of these two examples coincide. (ii) In cases with reflection-symmetric Hamiltonians, we use reflection positivity for Majoranas to characterize vortices in the ground states. Two additional methods suggest wider applicability of these results: (iii) Numerical evidence suggests similar behavior for certain systems without reflection symmetry. (iv) A perturbative analysis also suggests similar behavior without the assumption of reflection symmetry.

Chesi, Stefano [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada) [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada); CEMS, RIKEN, Wako, Saitama 351-0198 (Japan); Jaffe, Arthur [Harvard University, Cambridge, Massachusetts 02138 (United States) [Harvard University, Cambridge, Massachusetts 02138 (United States); Department of Physics, University of Basel, Basel (Switzerland); Institute for Theoretical Physics, ETH Zürich, Zürich (Switzerland); Loss, Daniel [CEMS, RIKEN, Wako, Saitama 351-0198 (Japan) [CEMS, RIKEN, Wako, Saitama 351-0198 (Japan); Department of Physics, University of Basel, Basel (Switzerland); Pedrocchi, Fabio L. [Department of Physics, University of Basel, Basel (Switzerland)] [Department of Physics, University of Basel, Basel (Switzerland)

2013-11-15

172

Dynamic PID loop control  

E-print Network

The Horizontal Test Stand (HTS) SRF Cavity and Cryomodule 1 (CM1) of eight 9-cell, 1.3GHz SRF cavities are operating at Fermilab. For the cryogenic control system, how to hold liquid level constant in the cryostat by regulation of its Joule-Thompson JT-valve is very important after cryostat cool down to 2.0 K. The 72-cell cryostat liquid level response generally takes a long time delay after regulating its JT-valve; therefore, typical PID control loop should result in some cryostat parameter oscillations. This paper presents a type of PID parameter self-optimal and Time-Delay control method used to reduce cryogenic system parameters' oscillation.

Pei, L; Theilacker, J; Soyars, W; Martinez, A; Bossert, R; DeGraff, B; Darve, C

2012-01-01

173

Determining the Optimum Number of Increments in Composite Sampling  

SciTech Connect

Composite sampling can be more cost effective than simple random sampling. This paper considers how to determine the optimum number of increments to use in composite sampling. Composite sampling can be more cost effective than simple random sampling. This paper considers how to determine the optimum number of increments to use in composite sampling. Composite sampling terminology and theory are outlined and a method is developed which accounts for different sources of variation in compositing and data analysis. This method is used to define and understand the process of determining the optimum number of increments that should be used in forming a composite. The blending variance is shown to have a smaller range of possible values than previously reported when estimating the number of increments in a composite sample. Accounting for differing levels of the blending variance significantly affects the estimated number of increments.

Hathaway, John E.; Schaalje, G Bruce; Gilbert, Richard O.; Pulsipher, Brent A.; Matzke, Brett D.

2008-09-30

174

Digital Parallel Processor Array for Optimum Path Planning  

NASA Technical Reports Server (NTRS)

The invention computes the optimum path across a terrain or topology represented by an array of parallel processor cells interconnected between neighboring cells by links extending along different directions to the neighboring cells. Such an array is preferably implemented as a high-speed integrated circuit. The computation of the optimum path is accomplished by, in each cell, receiving stimulus signals from neighboring cells along corresponding directions, determining and storing the identity of a direction along which the first stimulus signal is received, broadcasting a subsequent stimulus signal to the neighboring cells after a predetermined delay time, whereby stimulus signals propagate throughout the array from a starting one of the cells. After propagation of the stimulus signal throughout the array, a master processor traces back from a selected destination cell to the starting cell along an optimum path of the cells in accordance with the identity of the directions stored in each of the cells.

Kremeny, Sabrina E. (Inventor); Fossum, Eric R. (Inventor); Nixon, Robert H. (Inventor)

1996-01-01

175

Optimum two-impulse transfers for preliminary interplanetary trajectory design  

NASA Technical Reports Server (NTRS)

A method for numerically determining the optimum two-impulse transfer between two positions in two different heliocentric orbits is described. The formulas are based on earlier work by McCue and Bender (1965) for optimum two-impulse transfers between two orbits about the earth. The contours of minimum total Delta-V(Delta-V to launch plus Delta-V to achieve a given final orbit at the target body) are plotted on axes of true anomaly of the launch body at launch and true anomaly of the target body at arrival. The optimum transfers obtained are 'time-open' and the Delta-V from the initial orbit to the final orbit is found using patched conics. These 'prime rib' plots are useful for selecting initial conditions in the early phases of mission design.

Hulkower, N. D.; Lau, C. O.; Bender, D. F.

1984-01-01

176

Optimum control forces for multibody systems with intermittent motion  

NASA Technical Reports Server (NTRS)

The objective is to address the continuity of motion when a dynamical system is suddenly subjected to constraint conditions. Motion discontinuity due to the initial constraint violation is avoided by prior control forces that adjust the motion and yield velocity and acceleration consistent at the point of application of the constraint. The optimum control forces are determined for a specified control interval. The method proposed provides an optimum adjustment of the system's motion and assures that the stresses developed at the system components are kept within acceptable limits. The procedures developed will be illustrated making use of inequality constraints applied to obstacle avoidance problems in robotics.

Ider, Sitki Kemal; Amirouche, F. M. L.

1989-01-01

177

A first course in optimum design of yacht sails  

NASA Astrophysics Data System (ADS)

The optimum sail geometry is analytically obtained for the case of maximizing the thrust under equality and inequality constraints on the lift and the heeling moment. A single mainsail is assumed to be set close-hauled in uniform wind and upright on the flat sea surface. The governing parameters are the mast height and the gap between the sail foot and the sea surface. The lifting line theory is applied to analyze the aerodynamic forces acting on a sail. The design method consists of the variational principle and a feasibility study. Almost triangular sails are found to be optimum. Their advantages are discussed.

Sugimoto, Takeshi

1993-03-01

178

Optimum high temperature strength of two-dimensional nanocomposites  

SciTech Connect

High-temperature nanoindentation was used to reveal nano-layer size effects on the hardness of two-dimensional metallic nanocomposites. We report the existence of a critical layer thickness at which strength achieves optimal thermal stability. Transmission electron microscopy and theoretical bicrystal calculations show that this optimum arises due to a transition from thermally activated glide within the layers to dislocation transmission across the layers. We demonstrate experimentally that the atomic-scale properties of the interfaces profoundly affect this critical transition. The strong implications are that interfaces can be tuned to achieve an optimum in high temperature strength in layered nanocomposite structures.

Monclús, M. A.; Molina-Aldareguía, J. M., E-mail: jon.molina@imdea.org [IMDEA Materials Institute, C/Eric Kandel 2, 28906 Getafe, Madrid (Spain); Zheng, S. J.; Mayeur, J. R.; Beyerlein, I. J.; Mara, N. A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Polcar, T. [Czech Technical University in Prague, Technická 2, Prague 6 (Czech Republic); Llorca, J. [IMDEA Materials Institute, C/Eric Kandel 2, 28906 Getafe, Madrid (Spain); Department of Materials Science, Polytechnic University of Madrid, E. T. S. de Ingenieros de Caminos, 28040 Madrid (Spain)

2013-11-01

179

Nesting Loops March 7, 2012  

E-print Network

games, and we tied 0 games. You won the tournament! You may write your own messages to the user in as well. 1 Example: Nested For Loops Save this code in a .py file, and try running it. What do you see does it effect the behavior of the code, and why? 3 Example: If statement in a for loop Save this code

Lega, Joceline

180

Self-Similar Evaporation of a Rigidly-Rotating Cosmic String Loop  

E-print Network

The gravitational back-reaction on a certain type of rigidly-rotating cosmic string loop, first discovered by Allen, Casper and Ottewill, is studied at the level of the weak-field approximation. The near-field metric perturbations are calculated and used to construct the self-acceleration vector of the loop. Although the acceleration vector is divergent at the two kink points on the loop, its net effect on the trajectory over a single oscillation period turns out to be finite. The net back-reaction on the loop over a single period is calculated using a method due to Quashnock and Spergel, and is shown to induce a uniform shrinkage of the loop while preserving its original shape. The loop therefore evolves by self-similar evaporation.

Malcolm Anderson

2005-05-31

181

Loop-bed combustion apparatus  

DOEpatents

The present invention is directed to a combustion apparatus in the configuration of a oblong annulus defining a closed loop. Particulate coal together with a sulfur sorbent such as sulfur or dolomite is introduced into the closed loop, ignited, and propelled at a high rate of speed around the loop. Flue gas is withdrawn from a location in the closed loop in close proximity to an area in the loop where centrifugal force imposed upon the larger particulate material maintains these particulates at a location spaced from the flue gas outlet. Only flue gas and smaller particulates resulting from the combustion and innerparticle grinding are discharged from the combustor. This structural arrangement provides increased combustion efficiency due to the essentially complete combustion of the coal particulates as well as increased sulfur absorption due to the innerparticle grinding of the sorbent which provides greater particle surface area.

Shang, Jer-Yu (Fairfax, VA); Mei, Joseph S. (Morgantown, WV); Slagle, Frank D. (Kingwood, WV); Notestein, John E. (Morgantown, WV)

1984-01-01

182

On the factor set of code loops  

E-print Network

A Code loop on a binary linear code that is doubly even with a factor set is shown to be a central loop, conjugacy closed loop, Burn loop and extra loop. General forms of the identities that define the factor set of a code are deduced.

Temitope Gbolahan Jaiyeola

2008-06-05

183

Application of Smith Predictor Based on Single Neural Network in Cold Rolling Shape Control  

Microsoft Academic Search

Flatness is one of the most important criterion factors to evaluate the quality of the steel strip. To improve the strip's flatness quality, the most frequently used methodology is to employ the closed-loop automatic shape control system. However, in the shape control system, the shape-meter is always installed at the down way of the exit of the cold rolling mill

WANG Yiqun; SUN Fu; LIU Jian; SUN Menghui; XIE Yihan

2009-01-01

184

DNA looping and cleavage by restriction enzymes studied by manipulation of single DNA molecules with optical tweezers  

NASA Astrophysics Data System (ADS)

Looping and cleavage of single DNA molecules by the two-site restriction endonuclease Sau3AI were measured with optical tweezers. A DNA template containing many recognition sites was used, permitting loop sizes from ~10 to 10,000 basepairs. At high enzyme concentration cleavage events were detected within 5 seconds and nearly all molecules were cleaved within 5 minutes. Activity decreased ~10-fold as the DNA tension was increased from 0.03 to 0.7 pN. Substituting Ca 2+ for Mg 2+ blocked cleavage, permitting measurement of stable loops. At low tension, the initial rates of cleavage and looping were similar (~0.025 s -1 at 0.1 pN), suggesting that looping is rate limiting. Short loops formed more rapidly than long loops. The optimum size decreased from ~250 to 45 bp and the average number of loops (in 1 minute) from 4.2 to 0.75 as tension was increased from 0.03 to 0.7 pN. No looping was detected at 5 pN. These findings are in qualitative agreement with recent theoretical predictions considering only DNA mechanics, but we observed weaker suppression with tension and smaller loop sizes. Our results suggest that the span and elasticity of the protein complex and protein-induced DNA bending and wrapping play an important role.

Smith, Douglas E.; Gemmen, Gregory J.; Millin, Rachel

2006-08-01

185

Optimum design of dynamic response in automotive solenoid valve  

Microsoft Academic Search

It is pointed out that one of the most important points in designing an automotive electromagnetic actuator is to clarify the relationship between the response time and design factors. For optimum design, the main design factors (dimension, components, characteristics of the material of an actuator, and the applied voltage waveform) are primary concerns of actuator designers. Inducement of an eddy

Y. Ohdachi; Y. Kawase; Y. Murakami; Y. Inaguma

1991-01-01

186

Optimum Treatment Allocation in Clinical Trials Using Heteroscedastic Linear Models  

E-print Network

Optimum Treatment Allocation in Clinical Trials Using Heteroscedastic Linear Models Wei Zhu, Weng In clinical trials comparing several treatments, it is often the case that the response variance varies from and Donev, 1992; Fe­ dorov, 1972; Kiefer, 1974, 1985; Silvey, 1980) to design a randomized clinical trial

New York at Stoney Brook, State University of

187

Optimum Treatment Allocation for Dualobjective Clinical Trials with Binary Outcomes  

E-print Network

Optimum Treatment Allocation for Dual­objective Clinical Trials with Binary Outcomes Wei Zhu, Weng One common problem in many randomized clinical trials is how to assign patients to several treatment, although in reality, there are usually several objectives in a clinical trial. In this paper, optimal

New York at Stoney Brook, State University of

188

Optimum Transfer Guide: Public Relations Why Study Public Relations?  

E-print Network

, rela- tionship management and strategic plan- ning. Why Choose Texas Tech? The College of Mass in a foreign country. Talk to your advisor for more information. Graduate Education The College of MassOptimum Transfer Guide: Public Relations Why Study Public Relations? The Public Relations

Gelfond, Michael

189

Optimum Transfer Guide: Electronic Media & Communications Why Study Electronic Media?  

E-print Network

, and writing to provide a broad and thor- ough liberal arts education. Why Study EM&C at Texas Tech. Graduate Education The College of Mass Communications offers both the Masters of Arts and the DoctorOptimum Transfer Guide: Electronic Media & Communications Why Study Electronic Media

Gelfond, Michael

190

OPTIMUM ACTUATOR SELECTION WITH A GENETIC ALGORITHM FOR AIRCRAFT CONTROL  

E-print Network

be a source of aerodynamic noise and increased observability. Flow control actuators potentially allow been used to identify potential regions for the actuators, a genetic algorithm (GA) is an excellent tool for determining the optimum placement. The use of GA's has been instrumental in achieving good

Coello, Carlos A. Coello

191

Trends in mechanical fasteners. [considering optimum metric fastener system  

NASA Technical Reports Server (NTRS)

Some of the specialty fasteners which are enjoying increasing usage are: thread rolling screws, self drilling and tapping screws, locking screws, tamperproof fasteners, and flanged bolts and nuts. The development of an optimum metric fastener system is recommended for future fastener manufacturing.

Levy, J. B.

1972-01-01

192

Optimum control of heat exchangers with internal heat generation  

Microsoft Academic Search

This paper investigates the optimum control of a heat exchanger having internal heat sources from a reference steady state to a desired value. Both the wall and coolant are treated as distributed-parameter systems. Under certain constraints inherent in the operating conditions and physical limitations of the heat exchanger, the control function of the system, i.e. the heat generation rate which

H. S. Huang; W. J. Yang

1971-01-01

193

Optimum Design of Finite Dimensional Systems with Coincident Critical Points  

Microsoft Academic Search

1. Abstract The author's methods of design sensitivity analysis and optimization of coincident nonlinear critical load factors are shown to be effective for a finite dimensional system with moderately large numbers of design variables and degrees of freedom of displacements. Optimum designs under constraints on linear and nonlinear buckling load factors are found for spherical trusses subjected to distributed loads

Makoto Ohsaki; Yoshihiro Kanno

194

An Application of Calculus: Optimum Parabolic Path Problem  

ERIC Educational Resources Information Center

A practical and technological application of calculus problem is posed to motivate freshman students or junior high school students. A variable coefficient of friction is used in modelling air friction. The case in which the coefficient of friction is a decreasing function of altitude is considered. The optimum parabolic path for a flying object…

Atasever, Merve; Pakdemirli, Mehmet; Yurtsever, Hasan Ali

2009-01-01

195

Performance Based Measurement of Optimum Moisture for Soil Compaction  

E-print Network

Pressure Plate Matric Potential #12;WP4C Volumetric Water Content vs Matric Potential #12;WP4C: Effect will have a matric potential at the optimum water content near 250 kPa or less. Strictly a bench top soil in Proctor mold #12;WP4C Gravimetric Water Content vs Matric Potential #12;Relationship between

Minnesota, University of

196

Optimum fusion of visual and thermal face images for recognition  

Microsoft Academic Search

In this paper one investigation has been done to find the optimum level of fusion to find a fused image from visual as well as thermal images. Because of the use of face recognition system in critical areas like, authenticating an authorized person in highly secured areas, investigation of criminals, online monitoring etc, face recognition system should be very robust

Mrinal Kanti Bhowmik; Debotosh Bhattacharjee; Mita Nasipuri; Dipak Kumar Basu; Mahantapas Kundu

2010-01-01

197

Optimum Transfer Guide: Psychology Why Psychology at Texas Tech?  

E-print Network

, Cognitive/ Applied Cognitive Psychology, and Human Factors (accredited by the Human Factors and Ergonomics of the department (806) 742.0876 cctr@ttu.edu www.cctr.ttu.edu comprises programs in applied cognitive psychologyOptimum Transfer Guide: Psychology Why Psychology at Texas Tech? The Department of Psychology

Gelfond, Michael

198

Improved global sea surface temperature analyses using optimum interpolation  

Microsoft Academic Search

The new NOAA operational global sea surface temperature (SST) analysis is described. The analyses use 7 days of in situ (ship and buoy) and satellite SST. These analyses are produced weekly and daily using optimum interpolation (OI) on a 1[degrees] grid. The OI technique requires the specification of data and analysis error statistics. These statistics are derived and show that

Richard W. Reynolds; Thomas M. Smith

1994-01-01

199

Research on optimum location of urban land based on CA  

Microsoft Academic Search

The Optimum location of urban land is considered as an important issue of urban land intensive use. How to establish a technology road to realize this spatial location, objectively and quantitatively, has been the focus of current studies on urban land intensive use. During the summary of related studies at home and abroad, we try to establish the theory, methodology

Guoping Wu; Chonghui Song; Bo Wei; Qinshu Wu; Huichao Si

2007-01-01

200

Automatic planning concept - An analysis of optimum scheduling  

NASA Technical Reports Server (NTRS)

Study considers resource costs, mission constraints, and experiment results as linear functions, insofar as possible, in an effort to develop optimum scheduling by the use of linear programming. It involves a mathematical approach in which a number of constraints are considered operative.

Rebelein, P. R.; Truenbels, P.

1968-01-01

201

OPTIMUM COLOR SPACES FOR SKIN DETECTION Alberto Albiol  

E-print Network

the same person, under the same illumination conditions; and finally, skin colors change from person to person. Several color spaces have been proposed in the literature for skin detec- tion applications. YCbOPTIMUM COLOR SPACES FOR SKIN DETECTION Alberto Albiol , Luis Torres¡ , Edward J. Delp

Torres, Luis

202

Optimum Fuel Cell Utilization with Multilevel Inverters Burak Ozpineci1  

E-print Network

Optimum Fuel Cell Utilization with Multilevel Inverters Burak Ozpineci1 1 Oak Ridge National of semiconductors, this paper proposes a level reduction control using a multilevel inverter. Level reduction and increased efficiency. In this paper, a multilevel inverter is used to overcome some problems associated

Tolbert, Leon M.

203

A first course in optimum design of yacht sails  

Microsoft Academic Search

The optimum sail geometry is analytically obtained for the case of maximizing the thrust under equality and inequality constraints on the lift and the heeling moment. A single mainsail is assumed to be set close-hauled in uniform wind and upright on the flat sea surface. The governing parameters are the mast height and the gap between the sail foot and

Takeshi Sugimoto

1993-01-01

204

Optimum Income Taxation and Layo Taxes Pierre Cahucy  

E-print Network

Optimum Income Taxation and Layo¤ Taxes¤ Pierre Cahucy CREST-INSEE, Université Paris 1, CEPR, IZA to unemployment. It is shown that optimal tax schemes comprise both payroll and layo¤ taxes when the state provides public unemployment insurance and aims at redistributing income. The optimal layo¤ tax is equal

Boyer, Edmond

205

Modeling loop entropy.  

PubMed

Proteins fold from a highly disordered state into a highly ordered one. Traditionally, the folding problem has been stated as one of predicting "the" tertiary structure from sequential information. However, new evidence suggests that the ensemble of unfolded forms may not be as disordered as once believed, and that the native form of many proteins may not be described by a single conformation, but rather an ensemble of its own. Quantifying the relative disorder in the folded and unfolded ensembles as an entropy difference may therefore shed light on the folding process. One issue that clouds discussions of "entropy" is that many different kinds of entropy can be defined: entropy associated with overall translational and rotational Brownian motion, configurational entropy, vibrational entropy, conformational entropy computed in internal or Cartesian coordinates (which can even be different from each other), conformational entropy computed on a lattice, each of the above with different solvation and solvent models, thermodynamic entropy measured experimentally, etc. The focus of this work is the conformational entropy of coil/loop regions in proteins. New mathematical modeling tools for the approximation of changes in conformational entropy during transition from unfolded to folded ensembles are introduced. In particular, models for computing lower and upper bounds on entropy for polymer models of polypeptide coils both with and without end constraints are presented. The methods reviewed here include kinematics (the mathematics of rigid-body motions), classical statistical mechanics, and information theory. PMID:21187223

Chirikjian, Gregory S

2011-01-01

206

Adaptive shaping of femtosecond polarization profiles  

NASA Astrophysics Data System (ADS)

We report the experimental implementation of femtosecond polarization pulse shaping within an adaptive learning loop. This technique makes it possible to optimally and automatically generate light fields in which intensity, momentary frequency, and light polarization (i.e., ellipticity and orientation) change as a function of time within a single femtosecond laser pulse. By use of second-harmonic generation as a feedback signal in an evolutionary algorithm, specific phase- and polarization-modulated laser pulses are generated. Material dispersion and time-dependent modulations of the polarization state can be compensated. These experiments demonstrate the feasibility of adaptive quantum control experiments with polarization-shaped femtosecond laser pulses.

Brixner, T.; Damrauer, N. H.; Krampert, G.; Niklaus, P.; Gerber, G.

2003-05-01

207

Global optimum path planning for a redundant space robot  

NASA Astrophysics Data System (ADS)

Robotic manipulators will play a significant role in the maintenance and repair of space stations and satellites, and other future space missions. Robot path planning and control for the above applications should be optimum, since any inefficiency in the planning may considerably risk the success of the space mission. This paper presents a global optimum path planning scheme for redundant space robotic manipulators to be used in such missions. In this formulation, a variational approach is used to minimize the objective functional. Two optimum path planning problems are considered: first, given the end-effector trajectory, find the optimum trajectories of the joints, and second, given the terminal conditions of the end-effector, find the optimum trajectories for the end-effector and the joints. It is explicitly assumed that the gravity is zero in, and the robotic manipulator is mounted on a completely free-flying base (spacecraft) and the attitude control (reaction wheels or thrust jets) is off. Linear and angular momentum conditions for this system lead to a set of mixed holonomic an nonholonomic constraints. These equations are adjoined to the objective functional using a Lagrange multiplier technique. The formulation leads to a system of Differential and Algebraic Equations (DAEs) and a set of terminal conditions. A numerical scheme is presented for forward integration of the above system of DAEs, and an iterative shooting method is used to satisfy the terminal conditions. This approach is significant since most space robots that have been developed so far are redundant. The kinematic redundancy of space robots offers efficient control and provides the necessary dexterity for extra-vehicular activity or avoidance of potential obstacles in space stations.

Agrawal, Om P.; Xu, Yangsheng

1991-12-01

208

24—ANALYSIS OF THE DRY-RELAXED KNITTED-LOOP CONFIGURATION: PART I: TWO-DIMENSIONAL ANALYSIS  

Microsoft Academic Search

Models of the relaxed plain-knit structure proposed by previous workers suffer from the disadvantage of being based on the assumption of some geometrical shape for the knitted loop and are not derived from equilibrium considerations of the forces and couples applied to one loop by its neighbours. In the work described in this paper, the dry-relaxed knitted-loop configuration is considered

R. Postle; D. L. Munden

1967-01-01

209

Efficient aerodynamic shape optimization in MDO context  

NASA Astrophysics Data System (ADS)

Multidisciplinary analysis is necessary to reach physically meaningful optimum designs. For aero-structural shape optimization this means coupling two disciplines--aerodynamics and structural mechanics. In this paper, the sensitivity evaluation for aerodynamic shape optimization is considered, while taking into account the static aeroelastic effects introduced by the variations in the aerodynamic forces, which are associated with changes in the aerodynamic shape. Due to the high computational cost of a finite difference evaluation step for such a coupled problem, an extension of the adjoint approach to aeroelasticity is necessary for an efficient calculation of the sensitivities. The implementation, validation and application of such a method in the MDO context described above are presented.

Fazzolari, Antonio; Gauger, Nicolas R.; Brezillon, Joel

2007-06-01

210

Loop Quantum Gravity Phenomenology: Linking Loops to Observational Physics  

E-print Network

Research during the last decade demonstrates that effects originating on the Planck scale are currently being tested in multiple observational contexts. In this review we discuss quantum gravity phenomenological models and their possible links to loop quantum gravity. Particle frameworks, including kinematic models, broken and deformed Poincar\\'e symmetry, non-commutative geometry, relative locality and generalized uncertainty principle, and field theory frameworks, including Lorentz violating operators in effective field theory and non-commutative field theory, are discussed. The arguments relating loop quantum gravity to models with modified dispersion relations are reviewed, as well as, arguments supporting the preservation of local Lorentz invariance. The phenomenology related to loop quantum cosmology is briefly reviewed, with a focus on possible effects that might be tested in the near future. As the discussion makes clear, there remains much interesting work to do in establishing the connection between the fundamental theory of loop quantum gravity and these specific phenomenological models, in determining observational consequences of the characteristic aspects of loop quantum gravity, and in further refining current observations. Open problems related to these developments are highlighted. characteristic aspects of loop quantum gravity, and in further refining current observations. Open problems related to these developments are highlighted.

Florian Girelli; Franz Hinterleitner; Seth A. Major

2012-10-04

211

Plasma shape experiments for an optimized tokamak  

SciTech Connect

In this paper we present results from recent experiments at DIII-D which measured the plasma stability and confinement performance product, {beta}{tau}{sub E}, in one previously studied and three new plasma shapes. One important goal of these experiments was to identify performance vs shape trends which would identify a shape compatible with both high performance and the planned effort to decrease the power flux to the divertor floor using a closed ``slot`` divertor geometry. power flux to the divertor floor using a closed ``slot`` divertor geometry. The closed divertor hardware must be designed for a reduced set of plasma shapes, so care must be taken to choose the shape that optimizes {beta}{tau}{sub E} and divertor performance. The four shapes studied form a matrix of moderate and high elongations ({kappa} {congruent} 1.8 and 2.1) and low and high triangularities ({delta} {congruent} 0.3 and 0.9). All configurations were double-null diverted (DND), held fixed during a shot, with neutral beam heating. The shapes span a range of X-point locations compatible with the envisioned closed divertor. We find that from shape to shape, a shot`s transient normalized performance, {beta}{sub N}H, where {beta}{sub N} {equivalent_to} {beta}/(I{sup p})/aB{sub T} and H {equivalent_to} {tau}{sub E}/{tau}{sub E}{sup ITER-89P}, increases strongly with triangularity, but depends only weakly on elongation. However, the normalized performance during quasi stationary ELMing H-mode, to which these discharges eventually relax, is insensitive to both triangularity and elongation. The moderate elongation, high triangularity DND shape is shown to be near optimum for future studies on DIII-D.

Hyatt, A.W.; Osborne, T.H. [General Atomics, San Diego, CA (United States); Lazarus, E.A. [Oak Ridge National Lab., TN (United States)

1994-07-01

212

An optimum silica flour-bentonite mixture for an engineered barrier  

SciTech Connect

To dispose of low-level and mixed wastes (MAR) by burial, it is necessary to design an impermeable closure, which limits water infiltration through the waste. Bentonite has very low permeability to water but can be subject to volume alterations. Over time, these alterations can lead to channeling and subsequent permeability increases. The fluid conductivity and bulk properties of silica flour and bentonite mixtures were tested to find a mixture that would retain the low conductivity of the bentonite while maintaining volumetric stability. Silica flour was chosen for its small grain size and spherical shape, and its similarity to silty soil. Test results indicate that a 90% silica flour and 10% bentonite mixture will provide the optimum properties for this application. 5 refs., 2 figs., 2 tabs.

Walker, J.N.; Daffern, D.D.; Emer, D.F.

1991-01-01

213

IEEE JOURNAL OF QUANTUM ELECTRONICS, VOL. 42, NO. 7, JULY 2006 619 Design of Raman-Based Nonlinear Loop Mirror  

E-print Network

Loop Mirror for All-Optical 2R Regeneration of Differential Phase-Shift-Keying Transmission Sonia-shape regeneration and phase-noise reduction in high-speed differential phase-shift-keying transmission systems, differential phase-shift keying (DPSK), nonlinear optical loop mirror (NOLM), Raman amplification. I

Turitsyn, Sergei K.

214

PC Based Pulsed Field Hysteresis Loop Tracer  

NASA Astrophysics Data System (ADS)

The present paper describes the design and setting up of a PC based hysteresis loop tracer that enables quick characterization of magnetic materials at room temperature. A high magnetic field is generated in a solenoid by passing a pulse current of sinusoidal shape at an interval slow enough to produce minimum heating in the solenoid. A pickup coil system is kept in the solenoid to detect field and magnetization signal of a sample placed in the pickup coil. These transitory analog signals are converted into digital signals by a micro-controller integrated circuit. These digital signals are sent to a computer through a serial port. A software has been developed to interface the system to the PC and processing the data to calculate hysteresis parameters like saturation magnetization Ms, coercivity Hc and remanence Mr followed by plotting of the hysteresis loop. The data and graphs can be printed or stored as files. The sample holder is designed for samples in powder or pellet form. The data acquired for some standard magnetic samples are presented.

Likhite, S. D.; Likhite, Prachi; Radha, S.

2011-07-01

215

Integrated optical phase locked loop.  

SciTech Connect

A silicon photonics based integrated optical phase locked loop is utilized to synchronize a 10.2 GHz voltage controlled oscillator with a 509 MHz mode locked laser, achieving 32 fs integrated jitter over 300 kHz bandwidth.

Lentine, Anthony L.; Kim, Jungwon (Massachusetts Institute of Technology, Cambridge, MA); Trotter, Douglas Chandler; DeRose, Christopher T.; Kartner, Franz X. (Massachusetts Institute of Technology, Cambridge, MA); Byun, Hyunil (Massachusetts Institute of Technology, Cambridge, MA); Nejadmalayeri, Amir H. (Massachusetts Institute of Technology, Cambridge, MA); Watts, Michael R.; Zortman, William A.

2010-12-01

216

GENE LOOPS ENHANCE TRANSCRIPTIONAL DIRECTIONALITY  

PubMed Central

Eukaryotic genomes are extensively transcribed, forming both messenger (m) and noncoding (nc) RNAs. ncRNAs made by RNA polymerase II (Pol II) often initiate from bidirectional promoters (nucleosome-depleted chromatin) that synthesise mRNA and ncRNA in opposite directions. We demonstrate that actively transcribed mRNA encoding genes by adopting a gene loop conformation, restrict divergent transcription of ncRNAs. Since gene loop formation depends on a protein factor (Ssu72) that co-associates with both promoter and terminator, its inactivation leads to increased synthesis of promoter-associated divergent ncRNAs, referred to as Ssu72 restricted transcripts (SRT). Similarly, inactivation of individual gene loops by gene mutation enhances SRT synthesis. We demonstrate that gene loop conformation enforces transcriptional directionality on otherwise bidirectional promoters. PMID:23019609

Tan-Wong, Sue Mei; Zaugg, Judith B.; Camblong, Jurgi; Xu, Zhenyu; Zhang, David W.; Mischo, Hannah E.; Ansari, Aseem Z.; Luscombe, Nicholas M.; Steinmetz, Lars M.; Proudfoot, Nick J.

2012-01-01

217

Gene loops enhance transcriptional directionality.  

PubMed

Eukaryotic genomes are extensively transcribed, forming both messenger RNAs (mRNAs) and noncoding RNAs (ncRNAs). ncRNAs made by RNA polymerase II often initiate from bidirectional promoters (nucleosome-depleted chromatin) that synthesize mRNA and ncRNA in opposite directions. We demonstrate that, by adopting a gene-loop conformation, actively transcribed mRNA encoding genes restrict divergent transcription of ncRNAs. Because gene-loop formation depends on a protein factor (Ssu72) that coassociates with both the promoter and the terminator, the inactivation of Ssu72 leads to increased synthesis of promoter-associated divergent ncRNAs, referred to as Ssu72-restricted transcripts (SRTs). Similarly, inactivation of individual gene loops by gene mutation enhances SRT synthesis. We demonstrate that gene-loop conformation enforces transcriptional directionality on otherwise bidirectional promoters. PMID:23019609

Tan-Wong, Sue Mei; Zaugg, Judith B; Camblong, Jurgi; Xu, Zhenyu; Zhang, David W; Mischo, Hannah E; Ansari, Aseem Z; Luscombe, Nicholas M; Steinmetz, Lars M; Proudfoot, Nick J

2012-11-01

218

LacI-DNA-IPTG loops: equilibria among conformations by single-molecule FRET.  

PubMed

The E. coli Lac repressor (LacI) tetramer binds simultaneously to a promoter-proximal DNA binding site (operator) and an auxiliary operator, resulting in a DNA loop, which increases repression efficiency. Induction of the lac operon by allolactose reduces the affinity of LacI for DNA, but induction does not completely prevent looping in vivo. Our previous work on the conformations of LacI loops used a hyperstable model DNA construct, 9C14, that contains a sequence directed bend flanked by operators. Single-molecule fluorescence resonance energy transfer (SM-FRET) on a dual fluorophore-labeled LacI-9C14 loop showed that it adopts a single, stable, high-FRET V-shaped LacI conformation. Ligand-induced changes in loop geometry can affect loop stability, and the current work assesses loop population distributions for LacI-9C14 complexes containing the synthetic inducer IPTG. SM-FRET confirms that the high-FRET LacI-9C14 loop is only partially destabilized by saturating IPTG. LacI titration experiments and FRET fluctuation analysis suggest that the addition of IPTG induces loop conformational dynamics and re-equilibration between loop population distributions that include a mixture of looped states that do not exhibit high-efficiency FRET. The results show that repression by looping even at saturating IPTG should be considered in models for regulation of the operon. We propose that persistent DNA loops near the operator function biologically to accelerate rerepression upon exhaustion of inducer. PMID:23406418

Goodson, Kathy A; Wang, Zifan; Haeusler, Aaron R; Kahn, Jason D; English, Douglas S

2013-04-25

219

Optimum structural design with plate bending elements - A survey  

NASA Technical Reports Server (NTRS)

A survey is presented of recently published papers in the field of optimum structural design of plates, largely with respect to the minimum-weight design of plates subject to such constraints as fundamental frequency maximization. It is shown that, due to the availability of powerful computers, the trend in optimum plate design is away from methods tailored to specific geometry and loads and toward methods that can be easily programmed for any kind of plate, such as finite element methods. A corresponding shift is seen in optimization from variational techniques to numerical optimization algorithms. Among the topics covered are fully stressed design and optimality criteria, mathematical programming, smooth and ribbed designs, design against plastic collapse, buckling constraints, and vibration constraints.

Haftka, R. T.; Prasad, B.

1981-01-01

220

A Model for Constrained Optimum Water Pricing and Capacity Expansion  

NASA Astrophysics Data System (ADS)

Previous studies of optimum water pricing and capacity expansion have ignored the political and administrative factors which limit the range of feasible decisions. A general model is presented for identifying the water price horizon so as to maximize the present value of net benefits. Constraints on the range of water price, the rate of price change, and financial cost recovery are included in the model. The model is applied to a hypothetical case study of an urban water supply system. The results indicate that optimum water pricing and capacity expansion policies are likely to achieve some increase in economic benefits when compared with average cost pricing. Administrative and political constraints tend to reduce these benefits but result in more acceptable pricing policies.

Dandy, G. C.; McBean, E. A.; Hutchinson, B. G.

1984-05-01

221

Optimum detection of an optical image on a photoelectric surface.  

NASA Technical Reports Server (NTRS)

The image-detecting performance of an optimum counting detector is compared with that of a threshold detector and that of a detector basing its decisions on the total number of photoelectrons from a finite area of the image. The illuminance of the image is assumed to have a Gaussian spatial distribution. The optimum detector works with the pristine datum (and not with the photoelectric response) which is the spatiotemporal electromagnetic field at the aperture of the observing optical instrument. It is shown that little is to be gained by using details of the illuminance distribution beyond the crude knowledge of its breadth as embodied in a simple counter of emitted photoelectrons. All three detectors exhibit accordingly about the same reliability.

Helstrom, C. W.; Wang, L.

1973-01-01

222

Design of helicopter rotor blades for optimum dynamic characteristics  

NASA Technical Reports Server (NTRS)

The possibilities and the limitations of tailoring blade mass and stiffness distributions to give an optimum blade design in terms of weight, inertia, and dynamic characteristics are investigated. Changes in mass or stiffness distribution used to place rotor frequencies at desired locations are determined. Theoretical limits to the amount of frequency shift are established. Realistic constraints on blade properties based on weight, mass moment of inertia size, strength, and stability are formulated. The extent hub loads can be minimized by proper choice of EL distribution is determined. Configurations that are simple enough to yield clear, fundamental insights into the structural mechanisms but which are sufficiently complex to result in a realistic result for an optimum rotor blade are emphasized.

Peters, D. A.; Ko, T.; Korn, A. E.; Rossow, M. P.

1982-01-01

223

Design of helicopter rotor blades for optimum dynamic characteristics  

NASA Technical Reports Server (NTRS)

The possibilities and limitations of tailoring blade mass and stiffness distributions to give an optimum blade design in terms of weight, inertia, and dynamic characteristics are discussed. The extent that changes in mass of stiffness distribution can be used to place rotor frequencies at desired locations is determined. Theoretical limits to the amount of frequency shift are established. Realistic constraints on blade properties based on weight, mass, moment of inertia, size, strength, and stability are formulated. The extent that the hub loads can be minimized by proper choice of E1 distribution, and the minimum hub loads which can be approximated by a design for a given set of natural frequencies are determined. Aerodynamic couplings that might affect the optimum blade design, and the relative effectiveness of mass and stiffness distribution on the optimization procedure are investigated.

Peters, D. A.; Ko, T.; Korn, A. E.; Rossow, M. P.

1983-01-01

224

Ion energy scaling under optimum conditions of laser plasma acceleration  

E-print Network

A new, maximum proton energy, $e$, scaling law with the laser pulse energy, $E_L$ has been derived from the results of 3D particle-in-cell (PIC) simulations. Utilizing numerical modelling, protons are accelerated during interactions of the femtosecond relativistic laser pulses with the plain semi-transparent targets of optimum thickness [Esirkepov {\\it et al.} Phys. Rev. Lett. {\\bf 96}, 105001 (2206)]. The scaling, $e \\sim E_L^{0.7}$, has been obtained for the wide range of laser energies, different spot sizes, and laser pulse durations. Our results show that the proper selection of foil target optimum thicknesses, results in a very promising increase of the ion energy with the laser intensity even in the range of parameters below the radiation pressure (light sail) regime. The proposed analytical model is consistent with numerical simulations.

Brantov, A V; Bychenkov, V Yu; Rozmus, W

2014-01-01

225

A methodology for selecting optimum organizations for space communities  

NASA Technical Reports Server (NTRS)

This paper suggests that a methodology exists for selecting optimum organizations for future space communities of various sizes and purposes. Results of an exploratory study to identify an optimum hypothetical organizational structure for a large earth-orbiting multidisciplinary research and applications (R&A) Space Base manned by a mixed crew of technologists are presented. Since such a facility does not presently exist, in situ empirical testing was not possible. Study activity was, therefore, concerned with the identification of a desired organizational structural model rather than the empirical testing of it. The principal finding of this research was that a four-level project type 'total matrix' model will optimize the effectiveness of Space Base technologists. An overall conclusion which can be reached from the research is that application of this methodology, or portions of it, may provide planning insights for the formal organizations which will be needed during the Space Industrialization Age.

Ragusa, J. M.

1978-01-01

226

Physical Meaning of the Optimum Measurement Process in Quantum Detection Theory  

NASA Technical Reports Server (NTRS)

The optimum measurement processes are represented as the optimum detection operators in the quantum detection theory. The error probability by the optimum detection operators goes beyond the standard quantum limit automatically. However the optimum detection operators are given by pure mathematical descriptions. In order to realize a communication system overcoming the standard quantum limit, we try to give the physical meaning of the optimum detection operators.

Osaki, Masao; Kozuka, Haruhisa; Hirota, Osamu

1996-01-01

227

Optimum Design of High Speed Prop-Rotors  

NASA Technical Reports Server (NTRS)

The objective of this research is to develop optimization procedures to provide design trends in high speed prop-rotors. The necessary disciplinary couplings are all considered within a closed loop optimization process. The procedures involve the consideration of blade aeroelastic, aerodynamic performance, structural and dynamic design requirements. Further, since the design involves consideration of several different objectives, multiobjective function formulation techniques are developed.

Chattopadhyay, Aditi

1992-01-01

228

Motion estimation and optimum time selection for ship ISAR imaging  

Microsoft Academic Search

The problem of angular motion estimation and optimum time selection for ship ISAR imaging is addressed. The aim is to estimate ship angular motion and to select proper imaging intervals in order to obtain high quality top-view or side-view ship images suitable for processing by classification\\/identification procedures. To this purpose a novel analytical model for the phase\\/Doppler frequency of the

D. Pastina; A. Montanari; A. Aprile

2003-01-01

229

Analysis of spent beam refocusing to achieve optimum collector efficiency  

NASA Technical Reports Server (NTRS)

A reasonable criterion for evaluating the effectiveness of spent beam refocusing is the reduction of spent beam turbulence. The rms deviation of particle angles where the angles are calculated from the ratio of radial velocity to axial velocity is one measure of beam turbulence. It is demonstrated that the angular deviation can be reduced by almost half in some magnetic field configurations. Experimental evidence indicates that beam processing of this type is most likely to yield an optimum collector efficiency.

Stankiewicz, N.

1977-01-01

230

Improved target classification using optimum polarimetric SAR signatures  

Microsoft Academic Search

We present a new method for automatic target\\/object classification by using the optimum polarimetric radar signatures of the targets\\/objects of interest. The state-of-the-art in radar target recognition is based mostly either on the use of single polarimetric pairs or on the four preset pairs of orthogonal polarimetric signatures. Due to these limitations, polarimetric radar processing has been fruitful only in

FIROOZ SADJADI

2002-01-01

231

Generalized chirp-like polyphase sequences with optimum correlation properties  

Microsoft Academic Search

A new general class of polyphase sequences with ideal periodic autocorrelation function is presented. The new class of sequences is based on the application of Zadoff-Chu polyphase sequences of length N=sm2, where s and m are any positive integers. It is shown that the generalized chirp-like sequences of odd length have the optimum crosscorrelation function under certain conditions. Finally, recently

Branislav M. Popovic

1992-01-01

232

Optimum selection of an energy resource using fuzzy logic  

Microsoft Academic Search

Optimum selection of an energy resource is a vital issue in developed countries. Considering energy resources as alternatives (nuclear, hydroelectric, gas\\/oil, and solar) and factors upon which the proper decision will be taken as attributes (economics, availability, environmental impact, and proliferation), one can use the multi-attribute utility theory (MAUT) to optimize the selection process.Recently, fuzzy logic is extensively applied to

Ayah E. Abouelnaga; Abdelmohsen Metwally; Mohammad E. Nagy; Saeed Agamy

2009-01-01

233

Near-optimum decoding of product codes: block turbo codes  

Microsoft Academic Search

This paper describes an iterative decoding algorithm for any product code built using linear block codes. It is based on soft-input\\/soft-output decoders for decoding the component codes so that near-optimum performance is obtained at each iteration. This soft-input\\/soft-output decoder is a Chase decoder which delivers soft outputs instead of binary decisions. The soft output of the decoder is an estimation

Ramesh Mahendra Pyndiah

1998-01-01

234

Optimum Damping in a Non-Linear Base Isolation System  

NASA Astrophysics Data System (ADS)

Optimum isolation damping for minimum acceleration of a base-isolated structure subjected to earthquake ground excitation is investigated. The stochastic model of the El-Centro1940 earthquake, which preserves the non-stationary evolution of amplitude and frequency content of ground motion, is used as an earthquake excitation. The base isolated structure consists of a linear flexible shear type multi-storey building supported on a base isolation system. The resilient-friction base isolator (R-FBI) is considered as an isolation system. The non-stationary stochastic response of the system is obtained by the time dependent equivalent linearization technique as the force-deformation of the R-FBI system is non-linear. The optimum damping of the R-FBI system is obtained under important parametric variations; i.e., the coefficient of friction of the R-FBI system, the period and damping of the superstructure; the effective period of base isolation. The criterion selected for optimality is the minimization of the top floor root mean square (r.m.s.) acceleration. It is shown that the above parameters have significant effects on optimum isolation damping.

Jangid, R. S.

1996-02-01

235

Optimum Waveforms for Differential Ion Mobility Spectrometry (FAIMS)  

PubMed Central

Differential mobility spectrometry or field asymmetric waveform ion mobility spectrometry (FAIMS) is a new tool for separation and identification of gas-phase ions, particularly in conjunction with mass-spectrometry. In FAIMS, ions are filtered by the difference between mobilities in gases (K) at high and low electric field intensity (E) using asymmetric waveforms. An infinite number of possible waveform profiles make maximizing the performance within engineering constraints a major issue for FAIMS technology refinement. Earlier optimizations assumed the non-constant component of mobility to scale as E2, producing the same result for all ions. Here we show that the optimum profiles are defined by the full series expansion of K(E) that includes terms beyond the 1st that is proportional to E2. For many ion/gas pairs, the first two terms have different signs, and the optimum profiles at sufficiently high E in FAIMS may differ substantially from those previously reported, improving the resolving power by up to 2.2 times. This situation arises for some ions in all FAIMS systems, but becomes more common in recent miniaturized devices that employ higher E. With realistic K(E) dependences, the maximum waveform amplitude is not necessarily optimum and reducing it by up to ?20 – 30% is beneficial in some cases. The present findings are particularly relevant to targeted analyses where separation depends on the difference between K(E) functions for specific ions. PMID:18585054

Shvartsburg, Alexandre A.; Smith, Richard D.

2009-01-01

236

Optimum Design of Insulated Compression Plates Subjected to Aerodynamic Heating  

NASA Technical Reports Server (NTRS)

A method to determine the optimum thicknesses of insulation and load-carrying structure has been applied to insulated compression plates subjected to aerodynamic heating. The optimum design results in the lowest combined weight of insulation and load-carrying plate. Load parameters which included the imposed load, insulation conductivity and density, and flight time were found for design strength criteria of compressive yield, compressive buckling, and postbuckling failure. Charts of optimum total weight were prepared for 2024-T3 aluminum alloy, HK3lA magnesium alloy, 17-7 PH stainless steel, and Inconel X for each design criterion. The results show that 17-7 PH stainless steel and Inconel X are most efficient for compressive yield stress and that HK3lA magnesium is most efficient for buckling. HK31A magnesium is also most efficient for the postbuckling failure criterion except under conditions of light loading and long flight periods; under such conditions uninsulated Inconel X may be superior for environmental temperature less than 1,200 F. Insulated magnesium is more efficient than insulated aluminum because the lower density of magnesium permits the use of thick plates with large heat capacity. When more than one failure mode was applied to a design, it was found that the minimum weight structure was one in which all modes of failure occurred at the design load.

Davidson, John R.; Dalby, James F.

1961-01-01

237

Optimum design of structures subject to general periodic loads  

NASA Technical Reports Server (NTRS)

A simplified version of Icerman's problem regarding the design of structures subject to a single harmonic load is discussed. The nature of the restrictive conditions that must be placed on the design space in order to ensure an analytic optimum are discussed in detail. Icerman's problem is then extended to include multiple forcing functions with different driving frequencies. And the conditions that now must be placed upon the design space to ensure an analytic optimum are again discussed. An important finding is that all solutions to the optimality condition (analytic stationary design) are local optima, but the global optimum may well be non-analytic. The more general problem of distributing the fixed mass of a linear elastic structure subject to general periodic loads in order to minimize some measure of the steady state deflection is also considered. This response is explicitly expressed in terms of Green's functional and the abstract operators defining the structure. The optimality criterion is derived by differentiating the response with respect to the design parameters. The theory is applicable to finite element as well as distributed parameter models.

Reiss, Robert; Qian, B.

1989-01-01

238

Design of packed bed reactors: guides to catalyst shape, size, and loading selection  

Microsoft Academic Search

The engineering design of packed bed based unit operations is very much influenced by the structure of the packing matrix, which in turn is governed by the shape, dimensions and the loading of the constituent particles. For, say, reactor applications, optimum design of catalyst pellet in terms of shape configuration, internal pores and available surface area can promote catalytic activity

S Afandizadeh; E. A Foumeny

2001-01-01

239

Filter for third order phase locked loops  

NASA Technical Reports Server (NTRS)

Filters for third-order phase-locked loops are used in receivers to acquire and track carrier signals, particularly signals subject to high doppler-rate changes in frequency. A loop filter with an open-loop transfer function and set of loop constants, setting the damping factor equal to unity are provided.

Crow, R. B.; Tausworthe, R. C. (inventors)

1973-01-01

240

Hardware Loop Buffering Scott DiPasquale  

E-print Network

Hardware Loop Buffering Scott DiPasquale Khaled Elmeleegy C.J. Ganier Erik Swanson #12;Problem and Hypothesis n Compilers have more information about loops that they can exploit. n Hardware loop unrolling is highly complex. n Buffering loops reduces instruction count and improves performance with moderate

Rixner, Scott

241

Free loop spaces in topology and  

E-print Network

Free loop spaces in topology and physics Kathryn Hess What is the space of free loops? Enumeration of geodesics Hochschild and cyclic homology Homological conformal field theories Free loop spaces in topology Meeting of the Edinburgh Mathematical Society Glasgow, 14 November 2008 #12;Free loop spaces in topology

Thévenaz, Jacques

242

Beam shaping for holographic techniques  

NASA Astrophysics Data System (ADS)

Uniform intensity of laser radiation is very important in holographic and interferometry technologies, therefore transformation of typical Gaussian distribution of a TEM00 laser to flat-top (top hat) is an actual technical task, it is solved by applying beam shaping optics. Holography and interferometry have specific requirements to a uniform laser beam, most important of them are flatness of phase front and extended depth of field. There are different refractive and diffractive beam shaping approaches used in laser industrial and scientific applications, but only few of them are capable to fulfil the optimum conditions for beam quality demanding holography and interferometry. We suggest applying refractive field mapping beam shapers piShaper, which operational principle presumes almost lossless transformation of Gaussian to flat-top beam with flatness of output wavefront, conserving of beam consistency, providing collimated low divergent output beam, high transmittance, extended depth of field, negligible wave aberration, and achromatic design provides capability to work with several lasers with different wavelengths simultaneously. This approach is used in SLM-based technologies of Computer Generated Holography, Dot-Matrix mastering of security holograms, holographic data storage, holographic projection, lithography, interferometric recording of Volume Bragg Gratings. High optical quality of resulting flat-top beam allows applying additional optical components to vary beam size and shape, thus adapting an optical system to requirements of a particular application. This paper will describe design basics of refractive beam shapers and optical layouts of their applying in holographic systems. Examples of real implementations and experimental results will be presented as well.

Laskin, Alexander; Laskin, Vadim; Ostrun, Aleksei

2014-09-01

243

Creating the feedback loop: closed-loop neurostimulation.  

PubMed

Current DBS therapy delivers a train of electrical pulses at set stimulation parameters. This open-loop design is effective for movement disorders, but therapy may be further optimized by a closed loop design. The technology to record biosignals has outpaced our understanding of their relationship to the clinical state of the whole person. Neuronal oscillations may represent or facilitate the cooperative functioning of brain ensembles, and may provide critical information to customize neuromodulation therapy. This review addresses advances to date, not of the technology per se, but of the strategies to apply neuronal signals to trigger or modulate stimulation systems. PMID:24262909

Hebb, Adam O; Zhang, Jun Jason; Mahoor, Mohammad H; Tsiokos, Christos; Matlack, Charles; Chizeck, Howard Jay; Pouratian, Nader

2014-01-01

244

Loop coupled resonator optical waveguides.  

PubMed

We propose a novel coupled resonator optical waveguide (CROW) structure that is made up of a waveguide loop. We theoretically investigate the forbidden band and conduction band conditions in an infinite periodic lattice. We also discuss the reflection- and transmission- spectra, group delay in finite periodic structures. Light has a larger group delay at the band edge in a periodic structure. The flat band pass filter and flat-top group delay can be realized in a non-periodic structure. Scattering matrix method is used to calculate the effects of waveguide loss on the optical characteristics of these structures. We also introduce a tunable coupling loop waveguide to compensate for the fabrication variations since the coupling coefficient of the directional coupler in the loop waveguide is a critical factor in determining the characteristics of a loop CROW. The loop CROW structure is suitable for a wide range of applications such as band pass filters, high Q microcavity, and optical buffers and so on. PMID:25321995

Song, Junfeng; Luo, Lian-Wee; Luo, Xianshu; Zhou, Haifeng; Tu, Xiaoguang; Jia, Lianxi; Fang, Qing; Lo, Guo-Qiang

2014-10-01

245

Picophytoplankton physiology and the microbial loop  

NASA Astrophysics Data System (ADS)

Physiological observations are needed for a better understanding of the complexity of marine ecosystem processes. This information is important for a better model formulation and parameterisation to identify the consequences of, and feedbacks to, global change and to make future projections. Picophytoplankton form the smallest component of the phytoplankton community (˜ 3?m) and show a substantial contribution to phytoplankton biomass in oligotrophic oceans. Here they also have an important function as primary producers in the microbial loop. They include cyanobacteria, represented by Prochlorococcus and Synechococcus, and picoeukaryotes. The aim of this project is to achieve a better representation of picophytoplankton in the global biogeochemical model PlankTOM 10. PlankTOM 10 simplifies the complex ecosystem into 10 conceptual groups also known as plankton functional types (PFTs). These groups of organisms are defined by physiological and biochemical parameters (6 of phytoplankton, 3 of zooplankton and 1 of bacteria). Furthermore, the question will be addressed, whether picophytoplankton are typical K-strategists with low minimum nutrient and high maximum chlorophyll quota relative to carbon, or by having superior nutrient uptake kinetics and light harvesting (high ?Chl). Laboratory experiments showed that the smaller picoprokaryotes respond faster to increasing light intensities than their picoeukaryotic counterpart. Preliminary data show that the initial slope of the photosynthesis vs. irradiance curve (?Chl) of picoprokaryotes is about 1.5 times higher than of picoeukaryotes. This is consistent with their common distribution at the deep chlorophyll maximum. The maximum chlorophyll quota are not significantly different. Temperature experiments confirmed that the maximum growth rates of picophytoplankton at the optimum temperature (0.47 ± 0.17 d-1 for prokaryotes and 1.05 ± 0.47 d-1 for eukaryotes) are significantly lower than of diatoms (1.57 ± 0.73 d-1, Chollet et al. in prep.) and not significantly different from coccolithophores (0.68 ± 0.10 d-1, Buitenhuis et al. 2008), consistent with the characterisation of picophytoplanton as K-strategists. Their optimum temperatures were found to be 22.7 ± 2.0 ° C for prokaryotes and 23.6 ± 3.1 ° C for eukaryotes. Nutrient limitation experiments will be conducted to characterize the nutrient uptake and elemental composition of picophytoplankton. Finally the results of all experiments will then be used to improve the representation of picophytoplankton in PlankTOM10, evaluated against a recently compiled global database of picophytoplankton biomass.

Stawiarski, Beate

2013-04-01

246

Three-dimensional geometry of coronal loops inferred by the Principal Component Analysis  

NASA Astrophysics Data System (ADS)

We propose a new method for the determination of the three dimensional (3D) shape of coronal loops from stereoscopy. The common approach requires to find a 1D geometric curve, as circumference or ellipse, that best-fits the 3D tie-points which sample the loop shape in a given coordinate system. This can be easily achieved by the Principal Component (PC) analysis. It mainly consists in calculating the eigenvalues and eigenvectors of the covariance matrix of the 3D tie-points: the eigenvalues give a measure of the variability of the distribution of the tie-points, and the corresponding eigenvectors define a new cartesian reference frame directly related to the loop. The eigenvector associated with the smallest eigenvalues defines the normal to the loop plane, while the other two determine the directions of the loop axes: the major axis is related to the largest eigenvalue, and the minor axis with the second one. The magnitude of the axes is directly proportional to the square roots of these eigenvalues. The technique is fast and easily implemented in some examples, returning best-fitting estimations of the loop parameters and 3D reconstruction with a reasonable small number of tie-points. The method is suitable for serial reconstruction of coronal loops in active regions, providing a useful tool for comparison between observations and theoretical magnetic field extrapolations from potential or force-free fields.

Nisticò, Giuseppe; Nakariakov, Valery

247

Thermodynamics in Loop Quantum Cosmology  

E-print Network

Loop quantum cosmology (LQC) is very powerful to deal with the behavior of early universe. And the effective loop quantum cosmology gives a successful description of the universe in the semiclassical region. We consider the apparent horizon of the Friedmann-Robertson-Walker universe as a thermodynamical system and investigate the thermodynamics of LQC in the semiclassical region. The effective density and effective pressure in the modified Friedmann equation from LQC not only determine the evolution of the universe in LQC scenario but are actually also found to be the thermodynamic quantities. This result comes from the energy definition in cosmology (the Misner-Sharp gravitational energy) and is consistent with thermodynamic laws. We prove that within the framework of loop quantum cosmology, the elementary equation of equilibrium thermodynamics is still valid.

Li-Fang Li; Jian-Yang Zhu

2008-12-18

248

Optimized conical shaped charge design using the SCAP (Shaped Charge Analysis Program) code  

SciTech Connect

The Shaped Charge Analysis Program (SCAP) is used to analytically model and optimize the design of Conical Shaped Charges (CSC). A variety of existing CSCs are initially modeled with the SCAP code and the predicted jet tip velocities, jet penetrations, and optimum standoffs are compared to previously published experimental results. The CSCs vary in size from 0.69 inch (1.75 cm) to 9.125 inch (23.18 cm) conical liner inside diameter. Two liner materials (copper and steel) and several explosives (Octol, Comp B, PBX-9501) are included in the CSCs modeled. The target material was mild steel. A parametric study was conducted using the SCAP code to obtain the optimum design for a 3.86 inch (9.8 cm) CSC. The variables optimized in this study included the CSC apex angle, conical liner thickness, explosive height, optimum standoff, tamper/confinement thickness, and explosive width. The non-dimensionalized jet penetration to diameter ratio versus the above parameters are graphically presented. 12 refs., 10 figs., 7 tabs.

Vigil, M.G.

1988-09-01

249

Optimum Aerodynamic Design Using the Navier–Stokes Equations  

Microsoft Academic Search

:   This paper describes the formulation of optimization techniques based on control theory for aerodynamic shape design in viscous\\u000a compressible flow, modeled by the Navier–Stokes equations. It extends previous work on optimization for inviscid flow. The\\u000a theory is applied to a system defined by the partial differential equations of the flow, with the boundary shape acting as\\u000a the control. The

A. Jameson; L. Martinelli; N. A. Pierce

1998-01-01

250

Optimum performance of a regenerative Brayton thermal cycle  

NASA Astrophysics Data System (ADS)

The optimum performance of a regenerative Brayton cycle was analyzed. The model includes external and internal irreversibilities coming from four main sources: coupling to external heat reservoirs, turbine and compressor nonisentropic processes, pressure losses in the heater and the cooler, and the regenerator. In terms of the parameters accounting for each type of irreversibility, explicit numerical results are presented for the maximum efficiency, maximum power output, efficiency at maximum power output, power output at maximum efficiency, as well as for the pressure ratios required for maximum efficiency and maximum power. This analysis could provide a general theoretical tool for the optimal design and operation of real regenerative gas turbine power plants.

Roco, J. M. M.; Velasco, S.; Medina, A.; Hernández, A. Calvo

1997-09-01

251

Determination of optimum electrolyte composition for molten carbonate fuel cells  

SciTech Connect

The objective of this study is to determine the optimum electrolyte composition for molten carbonate fuel cells. To accomplish this, the contractor will provide: (1) Comprehensive reports of on-going efforts to optimize carbonate composition. (2) A list of characteristics affected by electrolyte composition variations (e.g. ionic conductivity, vapor pressure, melting range, gas solubility, exchange current densities on NiO, corrosion and cathode dissolution effects). (3) Assessment of the overall effects that these characteristics have state-of-the-art cell voltage and lifetime.

Yuh, C.Y.; Pigeaud, A.

1987-01-01

252

Determination of optimum electrolyte composition for molten carbonate fuel cells  

SciTech Connect

The objective of this study is to determine the optimum electrolyte composition for molten carbonate fuel cells. To accomplish this, the contractor will provide: (1) Comprehensive reports of on-going efforts to optimize carbonate composition. (2) A list of characteristics affected by electrolyte composition variations (e.g. ionic conductivity, vapor pressure, melting range, gas solubility, exchange current densities on NiO, corrosion and cathode dissolution effects). (3) Assessment of the overall effects that these characteristics have on state-of-the-art cell voltage and lifetime.

Pigeaud, A.

1986-01-01

253

Optimum value of original events on the PEPT technique  

SciTech Connect

Do Positron emission particle tracking (PEPT) has been used to track the motion of a single radioactively labeled tracer particle within a bed of similar particles. In this paper, the effect of the original event fraction on the results precise in two experiments has been reviewed. Results showed that the algorithm can no longer distinguish some corrupt trajectories, in addition to; further iteration reduces the statistical significance of the sample without improving its quality. Results show that the optimum value of trajectories depends on the type of experiment.

Sadremomtaz, Alireza; Taherparvar, Payvand [University of Guilan, P.O. Box 3489, Rasht, Guilan (Iran, Islamic Republic of)

2011-12-26

254

Design optimum frac jobs using virtual intelligence techniques  

NASA Astrophysics Data System (ADS)

Designing optimal frac jobs is a complex and time-consuming process. It usually involves the use of a two- or three-dimensional computer model. For the computer models to perform as intended, a wealth of input data is required. The input data includes wellbore configuration and reservoir characteristics such as porosity, permeability, stress and thickness profiles of the pay layers as well as the overburden layers. Among other essential information required for the design process is fracturing fluid type and volume, proppant type and volume, injection rate, proppant concentration and frac job schedule. Some of the parameters such as fluid and proppant types have discrete possible choices. Other parameters such as fluid and proppant volume, on the other hand, assume values from within a range of minimum and maximum values. A potential frac design for a particular pay zone is a combination of all of these parameters. Finding the optimum combination is not a trivial process. It usually requires an experienced engineer and a considerable amount of time to tune the parameters in order to achieve desirable outcome. This paper introduces a new methodology that integrates two virtual intelligence techniques, namely, artificial neural networks and genetic algorithms to automate and simplify the optimum frac job design process. This methodology requires little input from the engineer beyond the reservoir characterizations and wellbore configuration. The software tool that has been developed based on this methodology uses the reservoir characteristics and an optimization criteria indicated by the engineer, for example a certain propped frac length, and provides the detail of the optimum frac design that will result in the specified criteria. An ensemble of neural networks is trained to mimic the two- or three-dimensional frac simulator. Once successfully trained, these networks are capable of providing instantaneous results in response to any set of input parameters. These networks will be used as the fitness function for a genetic algorithm routine that will search for the best combination of the design parameters for the frac job. The genetic algorithm will search through the entire solution space and identify the optimal combination of parameters to be used in the design process. Considering the complexity of this task this methodology converges relatively fast, providing the engineer with several near-optimum scenarios for the frac job design. These scenarios, which can be achieved in just a minute or two, can be valuable initial points for the engineer to start his/her design job and save him/her hours of runs on the simulator.

Mohaghegh, Shahab; Popa, Andrei; Ameri, Sam

2000-10-01

255

Loop Quantum Geometry: A primer  

E-print Network

This is the written version of a lecture given at the ``VI Mexican School of Gravitation and Mathematical Physics" (Nov 21-27, 2004, Playa del Carmen, Mexico), introducing the basics of Loop Quantum Geometry. The purpose of the written contribution is to provide a Primer version, that is, a first entry into Loop Quantum Gravity and to present at the same time a friendly guide to the existing pedagogical literature on the subject. This account is geared towards graduate students and non-experts interested in learning the basics of the subject.

Corichi, A

2005-01-01

256

Loop Quantum Geometry: A primer  

E-print Network

This is the written version of a lecture given at the ``VI Mexican School of Gravitation and Mathematical Physics" (Nov 21-27, 2004, Playa del Carmen, Mexico), introducing the basics of Loop Quantum Geometry. The purpose of the written contribution is to provide a Primer version, that is, a first entry into Loop Quantum Gravity and to present at the same time a friendly guide to the existing pedagogical literature on the subject. This account is geared towards graduate students and non-experts interested in learning the basics of the subject.

Alejandro Corichi

2005-07-08

257

Integrable systems and loop coproducts  

NASA Astrophysics Data System (ADS)

We present a generalization of a framework for the construction of classical integrable systems that we call loop coproduct formulation (Musso 2010 J. Phys. A: Math. Theor. 43 434026). In this paper, the loop coproduct formulation includes systems of Gelfand-Tsetlin type, the linear r-matrix formulation, the Sklyanin algebras, the reflection algebras, the coalgebra symmetry approach and some of its generalizations as particular cases, showing that all these apparently different approaches have a common algebraic origin. On the other hand, all these subcases do not exhaust the domain of applicability of this new technique, so that new possible directions of investigation do naturally emerge in this framework.

Musso, Fabio

2010-11-01

258

[Hyperspectral optimum wavelengths and Fisher discrimination analysis to distinguish different concentrations of aflatoxin on corn kernel surface].  

PubMed

Aflatoxin is a toxic metabolite widely existing in corn. In the present paper, the feasibility of detecting aflatoxin on corn kernel surface by hyperspectral imaging technology was verified. The corn called pioneer with the same shape is provided by Toxicology and Mycotoxin Research Unit. With methanol configuration, four different concentrations of aflatoxin solutions were prepared and dripped on every 30 corn kernels. Also other clean 30 kernels without aflatoxin dripped were prepared to be the control samples. Among the 150 kernel samples, 103 training samples and 47 validation samples were prepared randomly. Firstly, hyperspectral image in the range of 400 to 1 000 nm was collected. For eliminating the deviations in original spectrum, standard normal variate transformation (SNV) was adopted as pretreatment method. And then several optimum wavelengths were selected by the principle of minimum misdiagnosis rate. After that the selected optimum wavelengths were taken as the input of the Fisher discrimination analysis to discriminate the different concentrations of aflatoxin on the corn. Finally, the discrimination model based on four optimum wavelengths (812.42, 873.00, 900.36 and 965.00 nm) was built and the accuracy of the model was tested. Results indicate that the classification accuracy of calibration and validation set was 87.4% and 80.9% respectively. This method provides basis for designing the corresponding portable instrument and distinguishing aflatoxin produced by naturally metabolism in corn. PMID:25269286

Chu, Xuan; Wang, Wei; Zhang, Lu-Da; Guo, Lang-Hua; Feldner, Peggy; Heitschmidt, Gerald

2014-07-01

259

Tracking performance and cycle slipping in the all-digital symbol synchronizer loop of the block 5 receiver  

NASA Technical Reports Server (NTRS)

Computer simulated noise performance of the symbol synchronizer loop (SSL) in the Block 5 receiver is compared with the theoretical noise performance. Good agreement is seen at the higher loop SNR's (SNR(sub L)'s), with gradual degradation as the SNR(sub L) is decreased. For the different cases simulated, cycle slipping is observed (within the simulation time of 10(exp 4) seconds) at SNR(sub L)'s below different thresholds, ranging from 6 to 8.5 dB, comparable to that of a classical phase-locked loop. An important point, however, is that to achieve the desired loop SNR above the seemingly low threshold to avoid cycle slipping, a large data-to-loop-noise power ratio, P(sub D)/(N(sub 0)B(sub L)), is necessary (at least 13 dB larger than the desired SNR(sub L) in the optimum case and larger otherwise). This is due to the large squaring loss (greater than or equal to 13 dB) inherent in the SSL. For the special case of symbol rates approximately equaling the loop update rate, a more accurate equivalent model accounting for an extra loop update period delay (characteristic of the SSL phase detector design) is derived. This model results in a more accurate estimation of the noise-equivalent bandwidth of the loop.

Aung, M.

1992-01-01

260

Optimum conditions for inducing laccase production in Lentinus crinitus.  

PubMed

Laccases are environmentally friendly alternatives in many important applications such as in bioremediation, biopulping, textile, and the food industry. They have wide substrate specificity, can oxidize a broad range of compounds, and show potential for use in various industrial processes. Therefore, developing methods to increase laccase production is important. In the current study, we aimed to identify optimum conditions for inducing laccase production in the basidiomycete Lentinus crinitus cultivated under varying nitrogen concentrations and in the presence of potential inducers of laccase production, including copper and phenolic compounds. Peak enzymatic activity (11,977 U/L) occurred at higher nitrogen concentrations (2.8 g/L nitrogen). Regardless of the nitrogen concentration, addition of copper increased the laccase activity and decreased mycelial growth, with maximum laccase activity (14,320 U/L) observed at the highest nitrogen concentration combined with 150 mM CuSO4. In addition, ethanol (0.5 or 1.0 mM) and guaiacol (1.5 mM) increased laccase production to 15,000, 14,800, and 14,850 U/L, respectively. Our findings highlighted the optimum conditions for producing L. crinitusderived laccase as potential alternatives to the conventional production and application of the enzyme. PMID:25366749

Valle, J S; Vandenberghe, L P S; Santana, T T; Almeida, P H; Pereira, A M; Linde, G A; Colauto, N B; Soccol, C R

2014-01-01

261

Optimum heat rejection temperatures for spacecraft heat pumps  

NASA Astrophysics Data System (ADS)

Use of two heat-rejection temperatures instead of one for a heat-driven heat pump is shown to reduce spacecraft waste-heat-radiator area and heat-rejection-system mass. The optimum high rejection temperature T(1) is shown to be somewhat less than Kerrebrock's rule, three-fourths of the heat source temperature T(H). The optimum low rejection temperature T(2) is 50-80 K above the cooling-load temperature T(C). General results are presented based upon the assumption of constant fractions of Carnot efficiency for the heat engine and refrigerator, and specific results are reported for a mercury-vapor engine coupled to an isobutane-R113 binary refrigerator. A single dimensionless grouping composed of ratios of equipment mass per unit power to radiator mass per unit area, and the ratios of the sink temperature and T(C) to T(H) are shown to be the major parameters characterizing the advantages of a spacecraft heat pump.

Edwards, D. K.; Richards, R. F.

1989-10-01

262

Characteristics of constrained optimum trajectories with specified range  

NASA Technical Reports Server (NTRS)

Necessary conditions of optimality are derived for trajectories whose structure is limited to climb, steady cruise, and descent segments. The performance function consists of the sum of fuel and time costs, referred to as direct operating cost (DOC). The state variable is range to go and the independent variable is energy. In this formulation a cruise segment always occurs at the optimum cruise energy for sufficiently large range. At short ranges (500 n. mi. and less) a cruise segment may also occur below the optimum cruise energy. The existence of such a cruise segment depends primarily on the fuel flow vs thrust characteristics and on thrust constraints. If thrust is a free control variable along with airspeed, it is shown that such cruise segments will not generally occur. If thrust is constrained to some maximum value in climb and to some minimum in descent, such cruise segments generally will occur. Computer calculations of typical short-range trajectories obtained about a 1% cost penalty for constraining the thrust.

Erzberger, H.; Lee, H.

1978-01-01

263

Optimum flywheel sizing for parallel and series hybrid vehicles  

SciTech Connect

Flywheels have the possibility of providing high turnaround efficiency and high specific power output. These characteristics are very important for the successful manufacture of parallel and series hybrid vehicles, which have the potential for providing high fuel economy and very low emissions with range and performance comparable to today`s light-duty vehicles. Flywheels have a high specific power output, but relatively low specific energy output. Therefore, it is of importance to determine energy and power requirements for flywheels applied to light-duty vehicles. Vehicle applications that require an energy storage system with high power and low energy are likely to benefit from a flywheel. In this paper, a vehicle simulation code and a flywheel model are applied to the calculation of optimum flywheel energy storage capacity for a parallel and a series hybrid vehicle. A conventional vehicle is also evaluated as a base-case, to provide an indication of the fuel economy gains that can be obtained with flywheel hybrid vehicles. The results of the analysis indicate that the optimum flywheel energy storage capacity is relatively small. This results in a low weight unit that has a significant power output and high efficiency. Emissions generated by the hybrid vehicles are not calculated, but have the potential of being significantly lower than the emissions from the conventional car.

Aceves, S.M.; Smith, J.R.

1996-12-20

264

Fine Structures and Overlying Loops of Confined Solar Flares  

E-print Network

Using the H$\\alpha$ observations from the New Vacuum Solar Telescope at Fuxian Solar Observatory, we focus on the fine structures of three confined flares and the issue why all the three flares are confined instead of eruptive. All the three confined flares take place successively at the same location and have similar morphologies, so can be termed homologous confined flares. In the simultaneous images obtained by the Solar Dynamics Observatory, many large-scale coronal loops above the confined flares are clearly observed in multi-wavelengths. At the pre-flare stage, two dipoles emerge near the negative sunspot, and the dipolar patches are connected by small loops appearing as arch-shaped H$\\alpha$ fibrils. There exists a reconnection between the small loops, and thus the H$\\alpha$ fibrils change their configuration. The reconnection also occurs between a set of emerging H$\\alpha$ fibrils and a set of pre-existing large loops, which are rooted in the negative sunspot, a nearby positive patch, and some remote ...

Yang, Shuhong; Xiang, Yongyuan

2014-01-01

265

A method for optimum PSA setting in the absence of a pure ? or ? emitter and its application in the determination of (237)Np/(233)Pa.  

PubMed

In the application of liquid scintillation counting (LSC), the ?/? discrimination is carried out with the function of pulse shape analysis (PSA), which requires the setting of the optimum PSA level. The optimum PSA are usually determined by the generation of cross-over plots, whereby a pair of vials, one containing a pure ? emitter and the other a pure ? emitter, is counted. However, in some cases such as the determination of (237)Np/(233)Pa, a pure ? emitter or a pure ? emitter is not available. Therefore, we have developed a new approach to set the optimum PSA by measuring the sample itself of mixed ?/? emitters. The count rate of the sample in the ?-multi-channel analyzer changes monotonically with the increase of the PSA, and there is always an inflection point which is related to the optimum PSA. By fitting the data near the inflection point with the function y=ax(3)+bx(2)+cx+d, we can obtain the optimum PSA as -b/(3a), which can be used to determine the radioactivity of (237)Np/(233)Pa. The results obtained with this new approach were in good agreement with those obtained by HPGe ? spectrometry that was calibrated with an LSC sample of (237)Np/(233)Pa under a radioactive secular equilibrium. The new approach is promising to be used in simultaneous determination of gross ? and ? emitters, especially in the absence of a pure ? or ? emitter. PMID:24582116

Feng, Xiao-gui; He, Qian-ge; Wang, Jian-chen; Chen, Jing

2014-11-01

266

Automatic loop steering for directional drilling  

SciTech Connect

A closed loop controller design for the steering of directed drilling is proposed in the paper. The paper first describes the development of a causal model of the directed drilling process that consists of two critical components. First a closed form bottom hole assembly (BHA) model is described. The BHA model makes it possible to solve the `inverse` problem on-line in real time. That is, having measured the `shape` of the compliant BHA at any instant, the real time BHA model will be used to determine both the exact location and orientation of the bit in a global reference frame and boundary conditions of the BHA at the rock/bit interface. Those boundary conditions include the instantaneous values of the net forces and moments at the rock/bit interface. Secondly, the paper describes a proposed input-output rock/bit interaction (RBI) model that can be shown to accurately determine the directional tendency of the bit on-line. The model structure is consistent with the models proposed by Ho (1987) and Rafie (1988) in the case when a constant build/drop rate is achieved. The model is shown to mimic field data which was published by Jogi et al (1988). The BHA and RBI models are then combined to yield a continuous differential model of the drilling process. It is assumed that force inputs to the BHA are obtained from continuously variable eccentric stabilizers in the BHA near the bit. A closed loop steering control algorithm is designed around the proposed drilling process model (DPM). Finally, simulations of the controlled DPM and an uncontrolled building BHA are compared to demonstrate the feasibility of the automatic steering controller.

Patten, W.N.; Kuehn, J.L.; Ziaja, M.B. [Univ. of Oklahoma, Norman, OK (United States)

1994-12-31

267

Parallel Loops Part I. Preliminaries  

E-print Network

Scaling Chapter 10. OpenMP Part III. Loosely Coupled Cluster Part IV. GPU Accelerator Part V. Map of the program. The loop iterates over the command line argument array, converts each number from a String; public class PrimeSeq extends Task { // Main program. public void main (String[] args) throws Exception

Kaminsky, Alan

268

Loop quantum gravity and observations  

E-print Network

Quantum gravity has long been thought to be completely decoupled from experiments or observations. Although it is true that smoking guns are still missing, there are now serious hopes that quantum gravity phenomena might be tested. We review here some possible ways to observe loop quantum gravity effects either in the framework of cosmology or in astroparticle physics.

Barrau, A

2014-01-01

269

Closed Loop Knowledge System (CLKS)  

Microsoft Academic Search

This paper will provide information about the benefits of the closed loop knowledge system (CLKS). CLKS is based on a robust warehouse-based data repository and support tools where data access, storage and predictive data mining exploitation can be obtained from a web interface which will enable better decision support for war fighters. Knowledge engineering and analysis of the data required

S. Head

2008-01-01

270

Loop Test/ Proper4es  

E-print Network

Paste Problem Mine Model Loop Test/ Paste Proper4es Data Analysis Opera4 is a mixture of fine tailings and some4mes other coarse material used to fill up or by mechanical pump, though the most opera4ons prefer to use gravity systems. The costs

Barthelat, Francois

271

while b do P While Loop  

E-print Network

while n #L do (s:= s + Ln. n:= n+1. t:= t+1) 4/118 #12;While Loop W while b do P means W if b then (P/118 #12;While Loop W while b do P means W if b then (P. W) else ok to prove s = s + L [n;..#L/118 #12;Exit Loop loop A. exit when b. C end 7/118 #12;Exit Loop L loop A. exit when b. C end 8/118 #12

Hehner, Eric C.R.

272

The Princeton Shape Benchmark  

Microsoft Academic Search

In recent years, many shape representations and geomet- ric algorithms have been proposed for matching 3D shapes. Usually, each algorithm is tested on a different (small) database of 3D models, and thus no direct comparison is available for competing methods. In this paper, we describe the Princeton Shape Bench- mark (PSB), a publicly available database of polygonal models collected from

Philip Shilane; Patrick Min; Michael M. Kazhdan; Thomas A. Funkhouser

2004-01-01

273

The Hue of Shapes  

ERIC Educational Resources Information Center

This article presents an experimental study on the naturally biased association between shape and color. For each basic geometric shape studied, participants were asked to indicate the color perceived as most closely related to it, choosing from the Natural Color System Hue Circle. Results show that the choices of color for each shape were not…

Albertazzi, Liliana; Da Pos, Osvaldo; Canal, Luisa; Micciolo, Rocco; Malfatti, Michela; Vescovi, Massimo

2013-01-01

274

3D Shapes Video  

NSDL National Science Digital Library

This upbeat music video reviews 3D shapes including the sphere, cylinder, cube, and cone. As each 3D shape is presented, examples of things we see every day that have the same shape are also shown for reinforcement. (Length: 3:18)

Kindergarten, Harry

2011-06-17

275

Bacterial cell shape  

Microsoft Academic Search

Bacterial species have long been classified on the basis of their characteristic cell shapes. Despite intensive research, the molecular mechanisms underlying the generation and maintenance of bacterial cell shape remain largely unresolved. The field has recently taken an important step forward with the discovery that eukaryotic cytoskeletal proteins have homologues in bacteria that affect cell shape. Here, we discuss how

Matthew T. Cabeen; Christine Jacobs-Wagner

2005-01-01

276

Querying Shapes of Histories  

Microsoft Academic Search

We present a shape definition language, called SDC, for retrieving objects based on shapes contained in the histories associated with these objects. It is a small, yet powerful, language that allows a rich variety of queries about the shapes found in historical time sequences. An interesting feature of SDC is its ability to perform blurry matching. A \\

Rakesh Agrawal; Giuseppe Psaila; Edward L. Wimmers; Mohamed Zaït

1995-01-01

277

Nonlinear adaptive filter for closed-loop fire control  

NASA Astrophysics Data System (ADS)

This paper presents an adaptive or self-learning filter design intended for use in real-time closed loop pointing control systems engaging multiple targets. The design approach is based upon use of a performance index (based upon the Mahalanobis generalized distance function) and multiple filters processed in parallel using the same nonlinear measurements as input. Application of performance index criteria to the statistics of individual filter residuals allows the selection of the optimum filter set without the time delays typically encountered and thereby allows the composite filter structure to adapt (or self-learn) to uncertainties in modeling target acceleration capabilities. An advantage of this approach is that it also provides to an operator (or a robotic controller) the confidence level of tracking system performance against a maneuvering target. This information is of interest for deployment of counter-measures (e.g., fire control eventing, alarms, engagement priority, etc) or simply for laboratory system tests of design adequacy.

Marshall, William C.

1990-09-01

278

Loop quantum gravity without the Hamiltonian constraint  

NASA Astrophysics Data System (ADS)

We show that under certain technical assumptions, including the existence of a constant mean curvature (CMC) slice and strict positivity of the scalar field, general relativity conformally coupled to a scalar field can be quantized on a partially reduced phase space, meaning reduced only with respect to the Hamiltonian constraint and a proper gauge fixing. More precisely, we introduce, in close analogy to shape dynamics, the generator of a local conformal transformation acting on both, the metric and the scalar field, which coincides with the CMC gauge condition. A new metric, which is invariant under this transformation, is constructed and used to define connection variables which can be quantized by standard loop quantum gravity methods. Since this connection is invariant under the local conformal transformation, the generator of which is shown to be a good gauge fixing for the Hamiltonian constraint, the Dirac bracket associated with implementing these constraints coincides with the Poisson bracket for the connection. Thus, the well developed kinematical quantization techniques for loop quantum gravity are available, while the Hamiltonian constraint has been solved (more precisely, gauge fixed) classically. The physical interpretation of this system is that of general relativity on a fixed spatial CMC slice, the associated ‘time’ of which is given by the CMC. While it is hard to address dynamical problems in this framework (due to the complicated ‘time’ function), it seems, due to good accessibility properties of the CMC gauge, to be well suited for problems such as the computation of black hole entropy, where actual physical states can be counted and the dynamics is only of indirect importance. The corresponding calculation yields the surprising result that the usual prescription of fixing the Barbero-Immirzi parameter ? to a constant value in order to obtain the well-known formula S = a(?)A/(4G) does not work for the black holes under consideration, while a recently proposed prescription involving an analytic continuation of ? to the case of a self-dual space-time connection yields the correct result. Also, the interpretation of the geometric operators gets an interesting twist, which exemplifies the deep relationship between observables and the choice of a time function and has consequences for loop quantum cosmology.

Bodendorfer, N.; Stottmeister, A.; Thurn, A.

2013-04-01

279

Optimum doping achieves high quantum yields in GaAs photoemitters  

NASA Technical Reports Server (NTRS)

Experimental data indicate that optimum doping exists. Measured quantum yield curves indicate optimum overall response is obtained in GaAs emitters with doping in high 10 to the 18th power per cu cm range. Doping for optimum response is not necessarily in this range.

Sonnenberg, H.

1971-01-01

280

Detecting and escaping infinite loops using Bolt  

E-print Network

In this thesis we present Bolt, a novel system for escaping infinite loops. If a user suspects that an executing program is stuck in an infinite loop, the user can use the Bolt user interface, which attaches to the running ...

Kling, Michael (Michael W.)

2012-01-01

281

Fragmentation of Cosmic-String Loops.  

National Technical Information Service (NTIS)

The fragmentation of cosmic string loops is discussed, and the results of a simulation of this process are presented. The simulation can evolve any of a large class of loops essentially exactly, including allowing fragments that collide to join together. ...

T. York

1989-01-01

282

[Optimum harvest study of Gentiana crassicaulis in Ludian].  

PubMed

The paper is aimed to study the difference in yield and quality at different harvest time and determine the optimum harvest of planting Gentiana in Ludian traditional harvest period. The authors analyzed the variation in fresh weight, dry weight, dry discount rate, length, diameter, volume and the content of gentiopicroside, loganin acid, alcohol-soluble extract and total ash and made a comprehensive appraisal of yield, appearance quality and intrinsic quality by gray relational distance ideal Comprehensive Evaluation method. The results showed that there is a big difference in yield and quality both 2-year-old and 3-year-old Gentiana harvested in traditional harvest period and the comprehensive evaluation more better when harvested more later. It can be seen, Gentiana harvested the later had a better yield and quality in Ludian traditional harvest period. The harvest of Gentiana can be appropriate delayed depending on the particular circumstances of production. PMID:25272487

Zeng, Yu; Chen, Xing-Fu; Zou, Yuan-Feng; Song, Jiu-Hua; Yang, Wen-Yu; Cheng, Tao

2014-07-01

283

Optimum compositions for thermal insulation of burners and regenerators  

SciTech Connect

The thermal and mechanical properties of thermal insulation compositions applied by spraying were evaluated to determine the optimum composition for the parameters posed by the burners and regenerators of glass-melting furnaces. The effects of varying spray parameters on these properties were also assessed. Changes were made in the binder density while leaving the amount of filler unaltered. With an increase in binder density there was an increase in the apparent density of the insulation. Kaolin wool with an aluminoborophosphate concentrate binder was tested for thermal conductivity, apparent density, and bending, shear, and compression strength against asbestos with water glass as a binder. For walls of the regenerators and a single-layer heat insulation, insulation made from an asbestos-perlite mixture with water glass was recommended.

Zasypkin, V.I.; Popov, O.N.

1988-07-01

284

Optimum detection of an optical image on a photoelectric surface  

NASA Technical Reports Server (NTRS)

The detection of an optical image in the presence of uniform background light is based on a likelihood ratio formed of the numbers of photoelectrons emitted from small elements of a photoelectric surface onto which the image is focused. When diffraction is negligible and the surface has unit quantum efficiency, this detector is equipollent with the optimum detector of the image forming light. Its performance is compared with that of the threshold detector and that of a detector basing its decisions on the total number of photoelectrons from a finite area of the image. The illuminance of the image is postulated to have a Gaussian spatial distribution. All three detectors exhibit nearly the same reliability.

Helstrom, C. W.; Wang, L.

1972-01-01

285

Optimum design of 2D micro-angle sensor  

NASA Astrophysics Data System (ADS)

To improve dynamic measurement performance and resolution, an optimum design on two-dimensional (2D) micro-angle sensor based on optical internal-reflection method via critical-angle refractive index measurement is presented in the paper. The noise signals were filtered effectively by modulating laser-driven and demodulating in signal proceeding. The system's accuracy and response speed are improved further by using 16-bit high-precision AD converter and MSP430 CPU which present with a high-speed performance during signals processes such as fitting angle-voltage curve through specific arithmetic, full range and zero point calibration, filter, scaling transformation etc. The experiment results indicated that, dynamic signal measurement range can be up to +/-600arcsec, the measurement resolution can be better than 0.1arcsec, and the repeatability could be better than +/-0.5arcsec.

Liu, Qinggang; Zhao, Heng; Lou, Xiaona; Jiang, Ningchuan; Hu, Xiaotang

2008-12-01

286

Optimum and efficient sampling for variational quantum Monte Carlo  

E-print Network

Quantum mechanics for many-body systems may be reduced to the evaluation of integrals in 3N dimensions using Monte-Carlo, providing the Quantum Monte Carlo ab initio methods. Here we limit ourselves to expectation values for trial wavefunctions, that is to Variational quantum Monte Carlo. Almost all previous implementations employ samples distributed as the physical probability density of the trial wavefunction, and assume the Central Limit Theorem to be valid. In this paper we provide an analysis of random error in estimation and optimisation that leads naturally to new sampling strategies with improved computational and statistical properties. A rigorous lower limit to the random error is derived, and an efficient sampling strategy presented that significantly increases computational efficiency. In addition the infinite variance heavy tailed random errors of optimum parameters in conventional methods are replaced with a Normal random error, strengthening the theoretical basis of optimisation. The method is ...

Trail, John Robert; 10.1063/1.3488651

2010-01-01

287

Robust Picture Matching Using Optimum Selection of Partial Templates  

NASA Astrophysics Data System (ADS)

In this paper, we propose the new template matching method with high speed, high accuracy and robustness, which works robustly under bad-conditioned situations as occlusion and shading. In this method, firstly, the Hierarchical Distributed Template Matching (HDTM) which we have already proposed makes rough positioning and pose estimation with high speed. Then, we estimate the optimum position and pose robustly by using the LMedS robust estimation and partial templates method. The experimental results for full-rotated target objects show that it achieved the accuracy of errors less than ±0.1 pixels and ±0.1 degrees, and the computing time were shorten up to about 1/20 to the conventional hierarchical search method.

Okuda, Haruhisa; Hashimoto, Manabu; Sumi, Kazuhiko; Sasaki, Kazunori

288

Simulation of an Optimum Multilevel Dynamic Round Robin Scheduling Algorithm  

NASA Astrophysics Data System (ADS)

CPU scheduling has valiant effect on resource utilization as well as overall quality of the system. Round Robin algorithm performs optimally in time shared systems, but it performs more number of context switches, larger waiting time and larger response time. In order to simulate the behavior of various CPU scheduling algorithms and to improve Round Robin scheduling algorithm using dynamic time slice concept, in this paper we produce the implementation of new CPU scheduling algorithm called An Optimum Multilevel Dynamic Round Robin Scheduling (OMDRRS), which calculates intelligent time slice and warps after every round of execution. The results display the robustness of this software, especially for academic, research and experimental use, as well as proving the desirability and efficiency of the probabilistic algorithm over the other existing techniques and it is observed that this OMDRRS projects good performance as compared to the other existing CPU scheduling algorithms.

Goel, Neetu; B. Garg, R.

2013-08-01

289

The optimum choice of gate width for neutron coincidence counting  

NASA Astrophysics Data System (ADS)

In the measurement field of international nuclear safeguards, passive neutron coincidence counting is used to quantify the spontaneous fission rate of certain special nuclear materials. The shift register autocorrelation analysis method is the most commonly used approach. However, the Feynman-Y technique, which is more commonly applied in reactor noise analysis, provides an alternative means to extract the correlation information from a pulse train. In this work we consider how to select the optimum gate width for each of these two time-correlation analysis techniques. The optimum is considered to be that which gives the lowest fractional precision on the net doublets rate. Our theoretical approach is approximate but is instructional in terms of revealing the key functional dependence. We show that in both cases the same performance figure of merit applies so that common design criteria apply to the neutron detector head. Our prediction is that near optimal results, suitable for most practical applications, can be obtained from both techniques using a common gate width setting. The estimated precision is also comparable in the two cases. The theoretical expressions are tested experimentally using 252Cf spontaneous fission sources measured in two thermal well counters representative of the type in common use by international inspectorates. Fast accidental sampling was the favored method of acquiring the Feynman-Y data. Our experimental study confirmed the basic functional dependences predicted although experimental results when available are preferred. With an appropriate gate setting Feynman-Y analysis provides an alternative to shift register analysis for safeguards applications which is opening up new avenues of data collection and data reduction to explore.

Croft, S.; Henzlova, D.; Favalli, A.; Hauck, D. K.; Santi, P. A.

2014-11-01

290

Fragmentation of cosmic-string loops  

NASA Technical Reports Server (NTRS)

The fragmentation of cosmic string loops is discussed, and the results of a simulation of this process are presented. The simulation can evolve any of a large class of loops essentially exactly, including allowing fragments that collide to join together. Such reconnection enhances the production of small fragments, but not drastically. With or without reconnections, the fragmentation process produces a collection of nonself-intersecting loops whose typical length is on the order of the persistence length of the initial loop.

York, Thomas

1989-01-01

291

Automation of loop amplitudes in numerical approach  

NASA Astrophysics Data System (ADS)

An automatic calculating system GRACE-L1 of one-loop Feynman amplitude is reviewed. This system can be applied to 2 to 2-body one-loop processes. A sample calculation of 2 to 3-body one-loop amplitudes is also presented.

Fujimoto, J.; Ishikawa, T.; Shimizu, Y.; Kato, K.; Nakazawa, N.; Kaneko, T.

1997-02-01

292

On hardware-in-the-loop simulation  

Microsoft Academic Search

Hardware-in-the-loop simulation is a well established technique used in design and evaluation of control systems. The purpose of this paper is twofold. First it aims to identify research questions related to the design of hardware-in-the-loop simulation. Second it suggests possible measures of assessing the simulation fidelity of hardware-the-loop simulation.

M. Bacic

2005-01-01

293

Hard thermal loops in static external fields  

E-print Network

We study, in the imaginary-time formalism, the high temperature behavior of n-point thermal loops in static Yang-Mills and gravitational fields. We show that in this regime, any hard thermal loop gives the same leading contribution as the one obtained by evaluating the loop at zero external energies and momenta.

J. Frenkel; S. H. Pereira; N. Takahashi

2009-02-04

294

Hard thermal loops in static external fields  

SciTech Connect

We examine, in the imaginary-time formalism, the high temperature behavior of n-point thermal loops in static Yang-Mills and gravitational fields. We show that in this regime, any hard thermal loop gives the same leading contribution as the one obtained by evaluating the loop integral at zero external energies and momenta.

Frenkel, J.; Takahashi, N. [Universidade de Sao Paulo, Instituto de Fisica Rua do Matao, Travessa R, 187-05508-090 Cidade Universitaria, Sao Paulo, SP (Brazil); Pereira, S. H. [Universidade de Sao Paulo, Instituto de Astronomia, Geofisica e Ciencias Atmosfericas Rua do Matao, 1226-05508-090 Cidade Universitaria, Sao Paulo, SP (Brazil)

2009-04-15

295

Loop control mechanism for scientific processor  

SciTech Connect

This patent describes a vector oriented scientific data processing system, a control mechanism for controlling program loops. It comprises: a first plurality of registers for storing a plurality of vector loop parameters; a current vector loop pointer register coupled to the first plurality of registers to select one of the first plurality of registers to provide current vector loop parameters; a second plurality of registers for storing a plurality of element loop parameters; a current element loop pointer register coupled to the second plurality of registers to select one of the second plurality or registers to provide current element loop parameters; a loop manipulation means having an input and an output means, coupled via its input means to be selected register of the first plurality of registers and by its output means to the selected register of the second plurality of registers. The loop manipulation means to provide at its output means an output signal indicative of the length of the loop stored in the selected register of the first plurality of registers; and the selected register of the second plurality of registers to provide an output signal indicative of a selected element in the length of the loop stored in the selected register of the second plurality of registers to provide a system for efficiently pre-computing loop lengths and thereby enhancing the speed of the vector oriented scientific data processing system.

Rusterholz, J.T.; Hamstra, J.R.

1989-09-19

296

Microgyroscope with closed loop output  

NASA Technical Reports Server (NTRS)

A micro-gyroscope (10) having closed loop operation by a control voltage (V.sub.TY), that is demodulated by an output signal of the sense electrodes (S1, S2), providing Coriolis torque rebalance to prevent displacement of the micro-gyroscope (10) on the output axis (y-axis). The present invention provides wide-band, closed-loop operation for a micro-gyroscope (10) and allows the drive frequency to be closely tuned to a high Q sense axis resonance. A differential sense signal (S1-S2) is compensated and fed back by differentially changing the voltage on the drive electrodes to rebalance Coriolis torque. The feedback signal is demodulated in phase with the drive axis signal (K.sub..omega..crclbar..sub.x) to produce a measure of the Coriolis force.

Challoner, A. Dorian (Inventor); Gutierrez, Roman C. (Inventor); Tang, Tony K. (Inventor); Cargille, Donald R. (Inventor)

2002-01-01

297

Noncontact guide system for traveling elastic steel plates: vibration control performance for different guideway shapes  

NASA Astrophysics Data System (ADS)

We have developed a noncontact guide system for a high-speed traveling elastic steel plate in which electromagnetic forces are applied by actuators at the edges of the plate to control its position. Recently, we have been examining a noncontact guide system, in which one of the loops of a belt-shaped thin steel plate is supported by a pulley, and another loop is guided without contact using electromagnets. It was confirmed experimentally that the loop shape of the thin steel plate changes with increasing traveling speed when no control is carried out. In this study, a basic examination of the technique for forming a guideway using electromagnets, in which the change in the uncontrolled loop shape is considered, was carried out. By comparing the results for guideways with several different shapes, the effect of the guideway shape on the vibration suppression performance of the steel plate was discussed experimentally. As a result, it was confirmed that the vibration suppression performance of the steel plate can be improved by adjusting the shape of the noncontact guide system that uses electromagnets to conform with that of the loop of the uncontrolled steel plate.

Kumagai, Hiroaki; Oshinoya, Yasuo; Ishibashi, Kazuhisa; Kasuya, Hirakazu

2007-12-01

298

Chiral logarithms to five loops  

E-print Network

We investigate two specific Green functions in the framework of chiral perturbation theory. We show that, using analyticity and unitarity, their leading logarithmic singularities can be evaluated in the chiral limit to any desired order in the chiral expansion, with a modest calculational cost. The claim is illustrated with an evaluation of the leading logarithm for the scalar two-point function to five-loop order.

Moritz Bissegger; Andreas Fuhrer

2006-12-08

299

Closed Loop Recycling of PreservativeClosed Loop Recycling of Preservative Treated WoodTreated Wood  

E-print Network

Closed Loop Recycling of PreservativeClosed Loop Recycling of Preservative Treated WoodTreated WoodDisposal problem Recycling potentialRecycling potential ValueValue--added productsadded products Closed loop recyclingClosed loop recycling #12;Major Current Disposal OptionsMajor Current Disposal Options Incineration

300

Analysis of a Small Loop Antenna With Inductive Coupling to Nearby Loops  

Microsoft Academic Search

This paper analyzes the inductive coupling that oc- curs when a loop antenna is near other conductive objects that form complete loops and are excited by incident low-frequency magnetic fields. The currents developed on the closed loops from the time changing magnetic fields generate their own magnetic fields that alter the voltage received by nearby open loop anten- nas. We

Michael P. Perkins; Mike M. Ong; Ron D. Speer

2011-01-01

301

Optimum interior area thermal resistance model to analyze the heat transfer characteristics of an insulated pipe with arbitrary shape  

Microsoft Academic Search

The heat transfer characteristics for an insulated regular polygonal (or circular) pipe are investigated by using a wedge thermal resistance model as well as the interior area thermal resistance model Rth=t\\/Ks\\/[(1??)A2+?A3] with a surface area weighting factor ?. The errors of the results generated by an interior area model can be obtained by comparing with the exact results generated by

Huann-Ming Chou

2003-01-01

302

Dispersion relations in loop calculations  

E-print Network

These lecture notes give a pedagogical introduction to the use of dispersion relations in loop calculations. We first derive dispersion relations which allow us to recover the real part of a physical amplitude from the knowledge of its absorptive part along the branch cut. In perturbative calculations, the latter may be constructed by means of Cutkosky's rule, which is briefly discussed. For illustration, we apply this procedure at one loop to the photon vacuum-polarization function induced by leptons as well as to the \\gamma f\\bar f vertex form factor generated by the exchange of a massive vector boson between the two fermion legs. We also show how the hadronic contribution to the photon vacuum polarization may be extracted from the total cross section of hadron production in e^+e^- annihilation measured as a function of energy. Finally, we outline the application of dispersive techniques at the two-loop level, considering as an example the bosonic decay width of a high-mass Higgs boson.

Kniehl, Bernd A

1996-01-01

303

Open-loop control of a MEMS deformable mirror for large-amplitude wavefront control  

E-print Network

Open-loop control of a MEMS deformable mirror for large-amplitude wavefront control Jason B for predicting control voltages that will generate a prescribed surface shape on a MEMS deformable mirror) for wavefront control in adaptive optics (AO) systems is primarily motivated by their high actuator density

304

Fast and Incremental Method for Loop-Closure Detection Using Bags of Visual Words  

Microsoft Academic Search

In robotic applications of visual simultaneous lo- calization and mapping techniques, loop-closure detection and global localization are two issues that require the capacity to recognize a previously visited place from current camera measurements. We present an online method that makes it possible to detect when an image comes from an already perceived scene using local shape and color information. Our

Adrien Angeli; David Filliat; Stéphane Doncieux; Jean-arcady Meyer

2008-01-01

305

Recovery of solitons with nonlinear amplifying loop mirrors  

NASA Astrophysics Data System (ADS)

We study the use of nonlinear amplifying loop mirrors to recover soliton pulses nonadiabatically deformed by losses. We approach this problem as a mapping problem of input pulse to output pulse, for segments of fiber followed by a combination of linear and nonlinear amplification. For a wide range of amplifier spacings, we find numerically that a single optimal input pulse of soliton shape exists for each amplifier spacing, which is well recovered at output. The recovered output pulses contain only \\similar 3% continuous radiation.

Gabitov, Ildar; Holm, Darryl D.; Luce, Benjamin P.; Mattheus, Arnold

1995-12-01

306

Keynote lecture: shape interrogation  

Microsoft Academic Search

Shape interrogation is the process of extraction of informationfrom a geometric model. It is a fundamental component of CAD\\/CAMsystems. In this lecture, we focus on shape interrogation ofgeometric models bounded by free-form or sculptured surfaces. Suchsurfaces are widely used in the bodies of ships, automobiles,aircraft, propeller and turbine blades, and various consumerdevices. Our basic thesis is that shape interrogation problems

Nicholas M. Patrikalakis

2003-01-01

307

Shape-Memory Polymers  

Microsoft Academic Search

Material scientists predict a prominent role in the future for self-repairing and intelligent materials. Throughout the last few years, this concept has found growing interest as a result of the rise of a new class of polymers. These so- called shape-memory polymers by far surpass well-known metallic shape- memory alloys in their shape-memory properties. As a consequence of the relatively

Andreas Lendlein; Steffen Kelch

2002-01-01

308

Conformal Radii for Conformal Loop Ensembles  

NASA Astrophysics Data System (ADS)

The conformal loop ensembles CLE ? , defined for 8/3 ? ? ? 8, are random collections of loops in a planar domain which are conjectured scaling limits of the O( n) loop models. We calculate the distribution of the conformal radii of the nested loops surrounding a deterministic point. Our results agree with predictions made by Cardy and Ziff and by Kenyon and Wilson for the O( n) model. We also compute the expectation dimension of the CLE ? gasket, which consists of points not surrounded by any loop, to be 2 - {(8 - kappa)(3kappa - 8)}/{32kappa} , which agrees with the fractal dimension given by Duplantier for the O( n) model gasket.

Schramm, Oded; Sheffield, Scott; Wilson, David B.

2009-05-01

309

Shape Optimization of Rubber Bushing Using Differential Evolution Algorithm  

PubMed Central

The objective of this study is to design rubber bushing at desired level of stiffness characteristics in order to achieve the ride quality of the vehicle. A differential evolution algorithm based approach is developed to optimize the rubber bushing through integrating a finite element code running in batch mode to compute the objective function values for each generation. Two case studies were given to illustrate the application of proposed approach. Optimum shape parameters of 2D bushing model were determined by shape optimization using differential evolution algorithm. PMID:25276848

2014-01-01

310

Optimum linear array for aperture synthesis imaging based on redundant spacing calibration  

NASA Astrophysics Data System (ADS)

Aperture synthesis imaging has been proved to be attractive in surveillance and detection applications. Such an imaging process is inevitably subject to aberrations introduced by instrument defects and/or turbulent media. Redundant spacing calibration (RSC) technique allows continuous calibration of these errors at any electromagnetic wavelength. However, it is based on specially designed array, in which just enough redundancy is included to permit the successful implementation of RSC. A new design criterion for linear RSC array is described, which introduces coverage efficiency and redundancy efficiency factors, aiming to find the perfect configurations, which have as complete uv-plane coverage as possible while containing required redundancy. Optimum linear arrays for N (number of subapertures) up to 10 are listed based on simulated annealing algorithm. The comparisons with existing linear RSC arrays with equivalent subaperture number are implemented. Results show that the optimized arrays have better performance of both optical transfer function, point spread function, and object reconstruction with reasonable value of the matrix condition number. After that, linear arrays are used to construct two-dimensional (2-D) pseudo-Y-shaped RSC arrays, which give a way to design 2-D RSC arrays without exhaustive searches.

Liu, Li; He, Yuntao; Zhang, Jianguo; Jia, Huayu; Ma, Jun

2014-05-01

311

Identification of optimum scopes of environmental factors for snails using spatial analysis techniques in Dongting Lake Region, China  

PubMed Central

Background Owing to the harmfulness and seriousness of Schistosomiasis japonica in China, the control and prevention of S. japonica transmission are imperative. As the unique intermediate host of this disease, Oncomelania hupensis plays an important role in the transmission. It has been reported that the snail population in Qiangliang Lake district, Dongting Lake Region has been naturally declining and is slowly becoming extinct. Considering the changes of environmental factors that may cause this phenomenon, we try to explore the relationship between circumstance elements and snails, and then search for the possible optimum scopes of environmental factors for snails. Methods Moisture content of soil, pH, temperature of soil and elevation were collected by corresponding apparatus in the study sites. The LISA statistic and GWR model were used to analyze the association between factors and mean snail density, and the values in high-high clustered areas and low-low clustered areas were extracted to find out the possible optimum ranges of these elements for snails. Results A total of 8,589 snail specimens were collected from 397 sampling sites in the study field. Besides the mean snail density, three environmental factors including water content, pH and temperature had high spatial autocorrelation. The spatial clustering suggested that the possible optimum scopes of moisture content, pH, temperature of the soil and elevation were 58.70 to 68.93%, 6.80 to 7.80, 22.73 to 24.23°C and 23.50 to 25.97 m, respectively. Moreover, the GWR model showed that the possible optimum ranges of these four factors were 36.58 to 61.08%, 6.541 to 6.89, 24.30 to 25.70°C and 23.50 to 29.44 m, respectively. Conclusion The results indicated the association between snails and environmental factors was not linear but U-shaped. Considering the results of two analysis methods, the possible optimum scopes of moisture content, pH, temperature of the soil and elevation were 58.70% to 68.93%, 6.6 to 7.0, 22.73°C to 24.23°C, and 23.5 m to 26.0 m, respectively. The findings in this research will help in making an effective strategy to control snails and provide a method to analyze other factors. PMID:24886456

2014-01-01

312

Optimum design of a gearbox for low vibration  

NASA Technical Reports Server (NTRS)

A computer program was developed for designing a low vibration gearbox. The code is based on a finite element shell analysis, a modal analysis, and a structural optimization method. In the finite element analysis, a triangular shell element with 18 degrees-of-freedom is used. In the optimization method, the overall vibration energy of the gearbox is used as the objective function and is minimized at the exciting frequency by varying the finite element thickness. Modal analysis is used to derive the sensitivity of the vibration energy with respect to the design variable. The sensitivity is representative of both eigenvalues and eigenvectors. The optimum value is computed by the gradient projection method and a unidimensional search procedure under the constraint condition of constant weight. The computer code is applied to a design problem derived from an experimental gearbox in use at the NASA Lewis Research Center. The top plate and two side plates of the gearbox are redesigned and the contribution of each surface to the total vibration is determined. Results show that optimization of the top plate alone is effective in reducing total gearbox vibration.

Inoue, Katsumi; Townsend, Dennis P.; Coy, John J.

1992-01-01

313

Selecting sprouts of brassicaceae for optimum phytochemical composition.  

PubMed

Cruciferous foods (Brassicaceae spp.) are rich in nutrients and bioactive compounds. Edible sprouts are becoming popular fresh foods and, therefore, the phytochemical profiling of nine varieties of Brassicaceae (broccoli, kohlrabi, red cabbage, rutabaga, turnip, turnip greens, radish, garden cress, and white mustard) was evaluated for this purpose. The glucosinolates in seeds were significantly higher than in sprouts, and day 8 of germination was considered the optimum for consumption. The sprouts with higher concentrations of glucosinolates in 8-day-old sprouts were white mustard, turnip, and kohlrabi (?815, ?766, and ?653 mg 100 g?¹ FW, respectively). Red cabbage and radish presented great total glucosinolates content (?516 and ?297 mg 100 g?¹ FW, respectively, in 8-day-old sprouts) and also higher total phenolic contents, biomass, and antioxidant capacity. The selection of the best performers in terms of germination quality and phytochemical composition is the key to optimize new fresh foods enriched in health-bioactive compounds. Further research on the bioavailability of the bioactive compounds in Brassica foods will allow backing of recommendations for dietarily effective dosages for nutrition and health. PMID:23061899

Baenas, Nieves; Moreno, Diego A; García-Viguera, Cristina

2012-11-14

314

Improved global sea surface temperature analyses using optimum interpolation  

SciTech Connect

The new NOAA operational global sea surface temperature (SST) analysis is described. The analyses use 7 days of in situ (ship and buoy) and satellite SST. These analyses are produced weekly and daily using optimum interpolation (OI) on a 1[degrees] grid. The OI technique requires the specification of data and analysis error statistics. These statistics are derived and show that the SST rms data errors from ships are almost twice as large as the data errors from buoys or satellites. In addition, the average e-folding spatial error scales have been found to be 850 km in the zonal direction and 615 km in the meridional direction. The analysis also includes a preliminary step that corrects any satellite biases relative to the in situ data using Poisson's equation. The importance of this correction is demonstrated using recent data following the 1991 eruptions of Mt. Pinatubo. The OI analysis has been computed using the in situ and bias-corrected satellite data for the period 1985 to present. 20 refs., 19 figs., 3 tabs.

Reynolds, R.W.; Smith, T.M. (National Meteorological Center, Washington, DC (United States))

1994-06-01

315

Optimum dimensions of power solenoids for magnetic suspension  

NASA Technical Reports Server (NTRS)

Design optimization of power solenoids for controllable and stabilizable magnetic suspensions with force compensation in a wind tunnel is shown. It is assumed that the model of a levitating body is a sphere of ferromagnetic material with constant magnetic permeability. This sphere, with a radius much smaller than its distance from the solenoid above, is to be maintained in position on the solenoid axis by balance of the vertical electromagnetic force and the force of gravitation. The necessary vertical (axial) force generated by the solenoid is expressed as a function of relevant system dimensions, solenoid design parameters, and physical properties of the body. Three families of curves are obtained which depict the solenoid power for a given force as a function of the solenoid length with either outside radius or inside radius as a variable parameter and as a function of the outside radius with inside radius as a variable parameter. The curves indicate the optimum solenoid length and outside radius, for minimum power, corresponding to a given outside radius and inside radius, respectively.

Kaznacheyev, B. A.

1985-01-01

316

Optimum Conditions for Artificial Fruiting Body Formation of Cordyceps cardinalis.  

PubMed

Stromatal fruiting bodies of Cordyceps cardinalis were successfully produced in cereals. Brown rice, German millet and standard millet produced the longest-length of stromata, followed by Chinese pearl barley, Indian millet, black rice and standard barley. Oatmeal produced the shortest-length of fruiting bodies. Supplementation of pupa and larva to the grains resulted in a slightly enhanced production of fruiting bodies; pupa showing better production than larva. 50~60 g of brown rice and 10~20 g of pupa mixed with 50~60 mL of water in 1,000 mL polypropylene (PP) bottle was found to be optimum for fruiting body production. Liquid inoculation of 15~20 mL per PP bottle produced best fruiting bodies. The optimal temperature for the formation of fruiting bodies was 25?, under conditions of continuous light. Few fruiting bodies were produced under the condition of complete darkness, and the fresh weight was considerable low, compared to that of light condition. PMID:23956641

Kim, Soo-Young; Shrestha, Bhushan; Sung, Gi-Ho; Han, Sang-Kuk; Sung, Jae-Mo

2010-06-01

317

Sea-land-line extraction using weighted optimum neighborhood algorithm  

NASA Astrophysics Data System (ADS)

In the field of automatic target recognition, research on automatic target recognition in water becomes increasingly important due to its value in maritime security and defense. Sea-land-line extraction under complicated sea-land-sky background plays an important role in water surface target recognition. The weighted optimum neighborhood algorithm is proposed by the feature of complicated sea-land-sky background images. Firstly pretreatment operations and Hough transform are taken in the image to find the potential sea-land-lines. There are several false sea-land-lines and a true sealand- line in these sea-land-lines. In the next step, the weighted values of the fitted sea-land lines' neighborhood are calculated and the fitted line, which has the biggest weighted value, is the correct sea-land-line. The experimental results show that the algorithm can detect the sea-land-line under complicated sea-land-sky background correctly and effectively, and has advantages such as strong robustness, more accurate and high practical value.

Lan, Jinhui; Jia, Zengli; Wu, Chunhong; Yang, Jun

2013-12-01

318

Fuel optimum low-thrust elliptic transfer using numerical averaging  

NASA Astrophysics Data System (ADS)

Low-thrust electric propulsion is increasingly being used for spacecraft missions primarily due to its high propellant efficiency. As a result, a simple and fast method for low-thrust trajectory optimization is of great value for preliminary mission planning. However, few low-thrust trajectory tools are appropriate for preliminary mission design studies. The method presented in this paper provides quick and accurate solutions for a wide range of transfers by using numerical orbital averaging to improve solution convergence and include orbital perturbations. Thus, preliminary trajectories can be obtained for transfers which involve many revolutions about the primary body. This method considers minimum fuel transfers using first-order averaging to obtain the fuel optimum rates of change of the equinoctial orbital elements in terms of each other and the Lagrange multipliers. Constraints on thrust and power, as well as minimum periapsis, are implemented and the equations are averaged numerically using a Gausian quadrature. The use of numerical averaging allows for more complex orbital perturbations to be added in the future without great difficulty. The effects of zonal gravity harmonics, solar radiation pressure, and thrust limitations due to shadowing are included in this study. The solution to a transfer which minimizes the square of the thrust magnitude is used as a preliminary guess for the minimum fuel problem, thus allowing for faster convergence to a wider range of problems. Results from this model are shown to provide a reduction in propellant mass required over previous minimum fuel solutions.

Tarzi, Zahi; Speyer, Jason; Wirz, Richard

2013-05-01

319

Operation of a Stark decelerator with optimum acceptance  

NASA Astrophysics Data System (ADS)

With a Stark decelerator, beams of neutral polar molecules can be accelerated, guided at a constant velocity, or decelerated. The effectiveness of this process is determined by the six-dimensional (6D) volume in phase space from which molecules are accepted by the Stark decelerator. Couplings between the longitudinal and transverse motion of the molecules in the decelerator can reduce this acceptance. These couplings are nearly absent when the decelerator operates such that only every third electric-field stage is used for deceleration, while extra transverse focusing is provided by the intermediate stages. For many applications, the acceptance of a Stark decelerator in this so-called s=3 mode significantly exceeds that of a decelerator in the conventionally used (s=1) mode. This has been experimentally verified by passing a beam of OH radicals through a 2.6-m -long Stark decelerator. The experiments are in quantitative agreement with the results of trajectory calculations, and can qualitatively be explained with a simple model for the 6D acceptance. These results imply that the 6D acceptance of a Stark decelerator in the s=3 mode of operation approaches the optimum value, i.e., the value that is obtained when any couplings are neglected.

Scharfenberg, Ludwig; Haak, Henrik; Meijer, Gerard; van de Meerakker, Sebastiaan Y. T.

2009-02-01

320

OPTIMUM INTEGRAL DESIGN FOR MAXIMIZING THE FIELD IN SHORT MAGNETS.  

SciTech Connect

An Optimum Integral Design is introduced for cosine(n{theta}) coils where the entire end-to-end length of the coil generates field with the dilution from ends practically eliminated. The benefits of such a design are particularly significant in short magnets where the overall coil length is comparable to or a few times the coil diameter. The integral field strength is further enhanced since the design allows a larger number of turns than in typical magnet coils. In this concept, the ends and body harmonics are optimized together to create an integral cosine(n{theta}) azimuthal current distribution. The concept was initially developed for wire/cable wound magnets where the bend radius of turns in the ends can be small. However, the benefit of this general approach can be applied to cable magnets as well. The magnetic design of a corrector dipole for the AGS helical magnet, which was recently built and tested, is presented as one of several examples. The other examples include a few sub-compact designs: a dipole with coil length less than a coil diameter, a quadrupole with coil length less than a coil radius, etc. Apart from generating a large integral field for the given length, the computed integral field harmonics in these designs are only a few parts in 10,000 at 2/3, of the coil radius.

GUPTA,R.

2004-10-03

321

Optimum Conditions for Artificial Fruiting Body Formation of Cordyceps cardinalis  

PubMed Central

Stromatal fruiting bodies of Cordyceps cardinalis were successfully produced in cereals. Brown rice, German millet and standard millet produced the longest-length of stromata, followed by Chinese pearl barley, Indian millet, black rice and standard barley. Oatmeal produced the shortest-length of fruiting bodies. Supplementation of pupa and larva to the grains resulted in a slightly enhanced production of fruiting bodies; pupa showing better production than larva. 50~60 g of brown rice and 10~20 g of pupa mixed with 50~60 mL of water in 1,000 mL polypropylene (PP) bottle was found to be optimum for fruiting body production. Liquid inoculation of 15~20 mL per PP bottle produced best fruiting bodies. The optimal temperature for the formation of fruiting bodies was 25?, under conditions of continuous light. Few fruiting bodies were produced under the condition of complete darkness, and the fresh weight was considerable low, compared to that of light condition. PMID:23956641

Kim, Soo-Young; Shrestha, Bhushan; Sung, Gi-Ho; Han, Sang-Kuk

2010-01-01

322

Action Alters Shape Categories  

ERIC Educational Resources Information Center

Two experiments show that action alters the shape categories formed by 2-year-olds. Experiment 1 shows that moving an object horizontally (or vertically) defines the horizontal (or vertical) axis as the main axis of elongation and systematically changes the range of shapes seen as similar. Experiment 2 shows that moving an object symmetrically (or…

Smith, Linda B.

2005-01-01

323

Numbers as Shapes  

NSDL National Science Digital Library

In this activity students are asked to relate the numbers 1- 20 to rectangular shapes. Learners use unit squares or cubes to sort numbers by their 'shapes,' either squares, rectangles or sticks (rectangles of unit width). Ideas for implementation, extension and support are included.

2011-08-01

324

Pan Balance - Shapes  

NSDL National Science Digital Library

This resource provides a virtual manipulative pan balance to explore and practice equality with geometric shapes. Each shape is assigned a certain weight. The pictorial representation is entered in a table and the items on each side of the balance can be represented by an algebraic expression.

Mathematics, Illuminations N.

2009-03-04

325

Building Big: Shapes Lab  

NSDL National Science Digital Library

Shapes Lab, from the PBS Building Big Series, shows how the shape of a structure affects its strength. Rectangles, arches, and triangles are compared for their distribution of stress and response to forces applied by the visitor. The site also contains information about forces, loads, and building materials.

2007-04-06

326

Shape Memory Alloys  

Microsoft Academic Search

This special issue on shape memory alloys (SMA) is an encore to a special issue on the same topic edited by us six years ago (Smart Mater. Struct.9 (5) October 2000). A total of 19 papers is offered in this issue, organized into the three broad categories of modeling, characterization and applications. In addition to thermally activated shape memory alloys,

Abhijit Bhattacharyya; Dimitris C Lagoudas

2007-01-01

327

Pan Balance-Shapes  

NSDL National Science Digital Library

This Java applet allows children to explore a balancing tool and thus build their algebraic thinking about equivalency. By placing shapes on each side of the balance and finding equivalent sets of weights, students discover the weight of each shape in one of six built-in sets or a random set.

2011-01-01

328

Pulse shaping system  

DOEpatents

Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses. 8 figs.

Skeldon, M.D.; Letzring, S.A.

1999-03-23

329

Pulse shaping system  

DOEpatents

Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses.

Skeldon, Mark D. (Penfield, NY); Letzring, Samuel A. (Jemez Springs, NM)

1999-03-23

330

Shaped composite liquid marbles.  

PubMed

Shaped "cubic" non-stick droplets are reported. Shaped composite droplets were manufactured via a two-stage process. In the first stage, cubic foamed-polystyrene particles were hydrophilized with cold radiofrequency plasma. Then particles were wetted with water. In the second stage, they were coated with solid, colloidal particles such as lycopodium, Teflon or carbon black. Thus, "liquid marble"-like non-stick shaped droplets were obtained. The shaped "cubic" droplets remained stable when supported by a NaCl water solution. Shaped Janus droplets coated on one side with dielectric Teflon and with semiconductor carbon black on the other side, were prepared. Janus marbles were actuated with an electric field. PMID:24407678

Bormashenko, Edward; Balter, Revital; Aharoni, Hadas; Aurbach, Doron

2014-03-01

331

Amplitude Control: Closing the Loop  

NASA Astrophysics Data System (ADS)

We are using a compensated zero-path-difference Michelson interferometer to control optical amplitude and phase for application to the correction of optical errors in telescopes. Two spatial light modulators are used in place of the usual mirrors in the Michelson. The spatial light modulators are 128x128 pixel arrays from Boulder Nonlinear Systems. We have previously shown how this device can be used for amplitude control using laser and white-light sources. In this study we will present results of closing the loop around this device with the purpose of making an incident optical field uniform in amplitude. This work is supported by NASA and Princeton University.

Littman, M. G.; Carr, M.; Kasdin, J.; Vanderbei, R.; Spergel, D.

2002-12-01

332

Coronal loops above an Active Region - observation versus model  

E-print Network

We conducted a high-resolution numerical simulation of the solar corona above a stable active region. The aim is to test the field-line braiding mechanism for a sufficient coronal energy input. We also check the applicability of scaling laws for coronal loop properties like the temperature and density. Our 3D-MHD model is driven from below by Hinode observations of the photosphere, in particular a high-cadence time series of line-of-sight magnetograms and horizontal velocities derived from the magnetograms. This driving applies stress to the magnetic field and thereby delivers magnetic energy into the corona, where currents are induced that heat the coronal plasma by Ohmic dissipation. We compute synthetic coronal emission that we directly compare to coronal observations of the same active region taken by Hinode. In the model, coronal loops form at the same places as they are found in coronal observations. Even the shapes of the synthetic loops in 3D space match those found from a stereoscopic reconstruction ...

Bourdin, Philippe-A; Peter, Hardi

2014-01-01

333

Looping of anisotropic, short double-stranded DNA  

NASA Astrophysics Data System (ADS)

Bending of double-stranded DNA (dsDNA) is associated with fundamental biological processes such as genome packaging and gene regulation, and therefore studying sequence-dependent dsDNA bending is a key to understanding biological impact of DNA sequence beyond the genetic code. Average mechanical behavior of long dsDNA is well described by the wormlike chain model, but sequence-dependent anisotropic bendability and bendedness of dsDNA can in principle lead to abnormally high looping probability at short length scales. Here, we measured the looping probability density (J factor) and kinetics of dsDNA as a function of length and curvature using single-molecule FRET (F"orster Resonance Energy Transfer). For theoretical comparison, we calculated the J-factor using a discrete dinucleotide chain model, and also simulated it by Monte Carlo methods. We provide evidences that even when the intrinsic shape of dsDNA is accounted for, the wormlike chain model fails to describe looping dynamics of dsDNA below 200-bp length scale.

Kim, Harold; Le, Tung

2013-03-01

334

Transportation Perspectives on Automotive Cyber Physical System: Integrating Hardware-in-the-Loop, Software-in-the-Loop and Human-in-the-Loop Simulations  

E-print Network

1 Transportation Perspectives on Automotive Cyber Physical System: Integrating Hardware-in-the-Loop of Virginia In transportation, the hardware in the loop simulation (HILS) and the software in the loop, Software-in-the-Loop and Human-in-the-Loop Simulations Byungkyu "Brian" Park and Sang H. Son University

Rajkumar, Ragunathan "Raj"

335

Optimum torque determination and selection of rotary shouldered drill collar connections  

E-print Network

and Torque Requirements of Drill Collar Connections for Optimum Performance Four-Point SummarY 13 EXPERIMENTAL PROCEDURE 15 Test Equipment Test Preparation Testing Procedure Make-up Test Bending Test 16 17 18 23 DATA REDUCTION 26 Make...-up Program Bending Program 27 27 Plotting Program THEORETICAL DEVELOPMENT 27 29 Farr's Modified Screw-Jack Formula 29 Optimum Torque Determination 30 DISCUSSION OF RESULTS 35 Optimum Torque Connection Performance 35 40 Fatigue Lif c vi...

Marlow, Roy Stone

2012-06-07

336

Intercomparison of numerical models of flaring coronal loops  

NASA Technical Reports Server (NTRS)

The proposed Benchmark Problem consists of an infinitesimal magnetic flux tube containing a low-beta plasma. The field strength is assumed to be so large that the plasma can move only along the flux tube, whose shape remains invariant with time (i.e., the fluid motion is essentially one-dimensional). The flux tube cross section is taken to be constant over its entire length. In planar view the flux tube has a semi-circular shape, symmetric about its midpoint s = s sub max and intersecting the chromosphere-corona interface (CCI) perpendicularly at each foot point. The arc length from the loop apex to the CCI is 10,000 km. The flux tube extends an additional 2000 km below the CCI to include the chromosphere, which initially has a uniform temperature of 8000 K. The temperature at the top of the loop was fixed initially at 2 X 1 million K. The plasma is assumed to be a perfect gas (gamma = 5/3), consisting of pure hydrogen which is considered to be fully ionized at all temperatures. For simplicity, moreover, the electron and ion temperatures are taken to be everywhere equal at all times (corresponding to an artificially enhanced electron-ion collisional coupling). While there was more-or-less unanimous agreement as to certain global properties of the system behavior (peak temperature reached, thermal-wave time scales, etc.), no two groups could claim satisfactory accord when a more detailed comparison of solutions was attempted.

Kopp, R. A.; Fisher, G. H.; Macneice, P.; Mcwhirter, R. W. P.; Peres, G.

1986-01-01

337

High frequency, high temperature specific core loss and dynamic B-H hysteresis loop characteristics of soft magnetic alloys  

NASA Technical Reports Server (NTRS)

Limited experimental data exists for the specific core loss and dynamic B-H loops for soft magnetic materials for the combined conditions of high frequency and high temperature. This experimental study investigates the specific core loss and dynamic B-H loop characteristics of Supermalloy and Metglas 2605SC over the frequency range of 1 to 50 kHz and temperature range of 23 to 300 C under sinusoidal voltage excitation. The experimental setup used to conduct the investigation is described. The effects of the maximum magnetic flux density, frequency, and temperature on the specific core loss and on the size and shape of the B-H loops are examined.

Wieserman, W. R.; Schwarze, G. E.; Niedra, J. M.

1990-01-01

338

High frequency, high temperature specific core loss and dynamic B-H hysteresis loop characteristics of soft magnetic alloys  

NASA Technical Reports Server (NTRS)

Limited experimental data exists for the specific core loss and dynamic B-H loop for soft magnetic materials for the combined conditions of high frequency and high temperature. This experimental study investigates the specific core loss and dynamic B-H loop characteristics of Supermalloy and Metglas 2605SC over the frequency range of 1 to 50 kHz and temperature range of 23 to 300 C under sinusoidal voltage excitation. The experimental setup used to conduct the investigation is described. The effects of the maximum magnetic flux density, frequency, and temperature on the specific core loss and on the size and shape of the B-H loops are examined.

Wieserman, W. R.; Schwarze, G. E.; Niedra, J. M.

1990-01-01

339

Shape Up America!  

NSDL National Science Digital Library

This site, maintained by Shape Up America! and Infosector Corporation, offers visitors a great way to keep up on the latest developments in weight management and physical fitness. Surveys, public service announcements, press releases and more are available. First-time visitors can determine their Body Mass Index (BMI), a ratio between weight and height that correlates with body fat. Shape Up America! also has beneficial information for the heath professional. Shape Up America! is a non-profit corporation established by C. Everett Koop, M.D., the former US Surgeon General.

1997-01-01

340

Temperature Analysis of 171-A Coronal Loops  

NASA Astrophysics Data System (ADS)

We searched the Atmospheric Imaging Assembly (AIA) database for observations of active region coronal loops seen in the 171-A images, which have a peak response temperature of Log T = 5.8. The twelve resulting loops were then analyzed to determine whether the cross-field temperature was isothermal or multithermal. A few of the twelve loops could be recognized as isothermal based on the narrowness of the resulting Differential Emission Measure (DEM) curves. These loops could then be modeled as a single magnetic flux tube. Most of the loops, however, were classified as multithermal as they have relatively broad DEM curves. These loops were more likely composed of several or even many magnetic strands, which might be tangled but are still able to confine plasma of different temperatures.

Worley, Brian T.; Schmelz, J. T.

2011-05-01

341

Higher Loop Nonplanar Anomalous Dimensions from Symmetry  

E-print Network

In this article we study the action of the one loop dilatation operator on operators with a classical dimension of order N. These operators belong to the su(2) sector and are constructed using two complex fields Y and Z. For these operators non-planar diagrams contribute already at the leading order in N and the planar and large N limits are distinct. The action of the one loop and the two loop dilatation operator reduces to a set of decoupled oscillators and factorizes into an action on the Z fields and an action on the Y fields. Direct computation has shown that the action on the Y fields is the same at one and two loops. In this article, using the su(2) symmetry algebra as well as structural features of field theory, we give compelling evidence that the factor in the dilatation operator that acts on the Ys is given by the one loop expression, at any loop order.

Robert de Mello Koch; Stuart Graham; Ilies Messamah

2013-12-21

342

Analysis of wasp-waist hysteresis loops  

NASA Astrophysics Data System (ADS)

Wasp-waist and pot-belly hysteresis loops have been observed in many materials. When only the major loop is reported, the results are insufficient to establish which processes are involved. We present two models for wasp-waist materials that produce virtually indistinguishable major loops, but show that first-order reversal curves can be used to separate the effects. In the simplest model, we take a soft magnetic material and a hard material and exchange couple them. When the exchange is positive, the loop is conventional. However, for negative (antiferromagnetic) exchange, the wasp-waist loop is obtained. Negative coupling of two materials with different switching field distributions leads to pot-bellied loops.

Bennett, Lawrence H.; Della Torre, Edward

2005-05-01

343

Scaling solution for small cosmic string loops.  

PubMed

The equation governing the time evolution of the number density of loops in a cosmic string network is a detailed balance determined by energy conservation. We solve this equation with the inclusion of the gravitational radiation effect, which causes the loops to shrink (and eventually decay) as time elapses. The solution approaches a scaling regime in which the total energy density in loops remains finite, converging both in the infrared and in the ultraviolet. PMID:18352539

Rocha, Jorge V

2008-02-22

344

Catheterization of intestinal loops in ruminants does not adversely affect loop function.  

PubMed

Catheterized intestinal loops may be a valuable model to elucidate key components of the host response to various treatments within the small intestine of ruminants. We examined whether catheterizing ileal loops in sheep affected the overall health of animals and intestinal function, whether a bacterial treatment could be introduced into the loops through the catheters, and whether broad-spectrum antibiotics could sterilize the loops. Escherichia coli cells transformed to express the GFP gene were introduced readily into the loops through the catheters, and GFP E. coli cells were localized within the injected loops. Catheterized loops, interspaces, and intact ileum exhibited no abnormalities in tissue appearance or electrical resistance. Expression of the IFN?, IL1?, IL4, IL6, IL12p40, IL18, TGF?1, and TNF? cytokine genes did not differ significantly among the intact ileum, catheterized loops, and interspaces, nor did the expression of the gene for inducible nitric oxide synthase. Broad-spectrum antibiotics administered during surgery did not sterilize the loops or interspaces and did not substantively change the composition of the microbiota. However, antibiotics reduced the overall number of bacterial cells within the loop and the relative abundance of community constituents. We concluded that catheterization of intestinal loops did not adversely affect health or loop function in sheep. Furthermore, allowing animals to recover fully from surgery and to clear pharmaceuticals will remove any confounding effects due to these factors, making catheterized intestinal loops a feasible model for studying host responses in ruminants. PMID:21262134

Inglis, G Douglas; Kastelic, John P; Uwiera, Richard R E

2010-12-01

345

Preliminary Economic Analysis And Design Guidelines For A Double Star Broadband Fiber Optic Subscriber Loop Network  

NASA Astrophysics Data System (ADS)

At the present time the copper twisted pair is limited in its transmission capabilities. In the long term it seems likely that the local loop will make greater use of fiber optic technology with the anticipated increase in the user demand for simultaneous transmission of high quality video, voice and high speed data. The current copper loop network is based on the star and double star configuration. This particular structure is familiar to the operating companies, and consequently deploying fiber in this configuration will allow for easier engineering, installation, operations, maintenance, records and administration. This paper reports on our preliminary analysis of providing fiber access to the subscriber directly from a central office or from an optically fed remote terminal. The focus is on the selection of the optimum location for the remote terminal based on the service requirements and economics under various scenarios.

Sharabianlou, Nasser; Chum, Stanley

1987-01-01

346

An automatic frequency control loop using overlapping DFTs (Discrete Fourier Transforms)  

NASA Technical Reports Server (NTRS)

An automatic frequency control (AFC) loop is introduced and analyzed in detail. The new scheme is a generalization of the well known Cross Product AFC loop that uses running overlapping discrete Fourier transforms (DFTs) to create a discriminator curve. Linear analysis is included and supported with computer simulations. The algorithm is tested in a low carrier to noise ratio (CNR) dynamic environment, and the probability of loss of lock is estimated via computer simulations. The algorithm discussed is a suboptimum tracking scheme with a larger frequency error variance compared to an optimum strategy, but offers simplicity of implementation and a very low operating threshold CNR. This technique can be applied during the carrier acquisition and re-acquisition process in the Advanced Receiver.

Aguirre, S.

1988-01-01

347

Computer program CORDET. [computerized simulation of digital phase-lock loop for Omega navigation receiver  

NASA Technical Reports Server (NTRS)

A FORTRAN 4 computer program provides convenient simulation of an all-digital phase-lock loop (DPLL). The DPLL forms the heart of the Omega navigation receiver prototype. Through the DPLL, the phase of the 10.2 KHz Omega signal is estimated when the true signal phase is contaminated with noise. This investigation has provided a convenient means of evaluating loop performance in a variety of noise environments, and has proved to be a useful tool for evaluating design changes. The goals of the simulation are to: (1) analyze the circuit on a bit-by-bit level in order to evaluate the overall design; (2) see easily the effects of proposed design changes prior to actual breadboarding; and (3) determine the optimum integration time for the DPLL in an environment typical of general aviation conditions.

Palkovic, R. A.

1974-01-01

348

Loop-mediated isothermal amplification (LAMP) method for detection of genetically modified maize T25  

PubMed Central

The loop-mediated isothermal amplification (LAMP) assay indicates a potential and valuable means for genetically modified organism (GMO) detection especially for its rapidity, simplicity, and low cost. We developed and evaluated the specificity and sensitivity of the LAMP method for rapid detection of the genetically modified (GM) maize T25. A set of six specific primers was successfully designed to recognize six distinct sequences on the target gene, including a pair of inner primers, a pair of outer primers, and a pair of loop primers. The optimum reaction temperature and time were verified to be 65°C and 45 min, respectively. The detection limit of this LAMP assay was 5 g kg?1 GMO component. Comparative experiments showed that the LAMP assay was a simple, rapid, accurate, and specific method for detecting the GM maize T25. PMID:24804053

Xu, Junyi; Zheng, Qiuyue; Yu, Ling; Liu, Ran; Zhao, Xin; Wang, Gang; Wang, Qinghua; Cao, Jijuan

2013-01-01

349

Loop-mediated isothermal amplification (LAMP) method for detection of genetically modified maize T25.  

PubMed

The loop-mediated isothermal amplification (LAMP) assay indicates a potential and valuable means for genetically modified organism (GMO) detection especially for its rapidity, simplicity, and low cost. We developed and evaluated the specificity and sensitivity of the LAMP method for rapid detection of the genetically modified (GM) maize T25. A set of six specific primers was successfully designed to recognize six distinct sequences on the target gene, including a pair of inner primers, a pair of outer primers, and a pair of loop primers. The optimum reaction temperature and time were verified to be 65°C and 45 min, respectively. The detection limit of this LAMP assay was 5 g kg(-1) GMO component. Comparative experiments showed that the LAMP assay was a simple, rapid, accurate, and specific method for detecting the GM maize T25. PMID:24804053

Xu, Junyi; Zheng, Qiuyue; Yu, Ling; Liu, Ran; Zhao, Xin; Wang, Gang; Wang, Qinghua; Cao, Jijuan

2013-11-01

350

Multi-instrument observations of coronal loops  

NASA Astrophysics Data System (ADS)

This document exhibits results of analysis from data collected with multiple EUV satellites (SOHO, TRACE, STEREO, Hinode, and SDO). The focus is the detailed observation of coronal loops using multiple instruments, i.e. filter imagers and spectrometers. Techniques for comparing the different instruments and deriving loop parameters are demonstrated. Attention is given to the effects the different instruments may introduce into the data and their interpretation. The assembled loop parameters are compared to basic energy balance equations and scaling laws. Discussion of the blue-shifted, asymmetric, and line broadened spectral line profiles near the footpoints of coronal loops is made. The first quantitative analysis of the anti-correlation between intensity and spectral line broadening for isolated regions along loops and their footpoints is presented. A magnetic model of an active region shows where the separatrices meet the photospheric boundary. At the boundary, the spectral data reveal concentrated regions of increased blue-shifted outflows, blue wing asymmetry, and line broadening. This is found just outside the footpoints of bright loops. The intensity and line broadening in this region are anti-correlated. A comparison of the similarities in the spectroscopic structure near the footpoints of the arcade loops and more isolated loops suggests the notion of consistent structuring for the bright loops forming an apparent edge of an active region core.

Scott, Jason Terrence

351

Hard-thermal-loop QED thermodynamics  

E-print Network

The weak-coupling expansion for thermodynamic quantities in thermal field theories is poorly convergent unless the coupling constant is tiny. We discuss the calculation of the free energy for a hot gas of electrons and photons to three-loop order using hard-thermal-loop perturbation theory (HTLpt). We show that the hard-thermal-loop perturbation reorganization improves the convergence of the successive approximations to the QED free energy at large coupling, e ~ 2. The reorganization is gauge invariant by construction, and due to the cancellations among various contributions, we obtain a completely analytic result for the resummed thermodynamic potential at three loops.

Nan Su; Jens O. Andersen; Michael Strickland

2009-11-24

352

Loops in One Dimensional Random Walks  

E-print Network

Distribution of loops in a one-dimensional random walk (RW), or, equivalently, neutral segments in a sequence of positive and negative charges is important for understanding the low energy states of randomly charged polymers. We investigate numerically and analytically loops in several types of RWs, including RWs with continuous step-length distribution. We show that for long walks the probability density of the longest loop becomes independent of the details of the walks and definition of the loops. We investigate crossovers and convergence of probability densities to the limiting behavior, and obtain some of the analytical properties of the universal probability density.

Shay Wolfling; Yacov Kantor

1999-02-01

353

The emergy analysis of loop circuit.  

PubMed

Emergy analysis can analyze the resource utilization and environmental performance of a system. Loop circuit is a common structure in the process industry, but when emergy analysis is carried out to such structure, mistakes such as emergy double counting often occur. To avoid emergy double counting, two types of loop circuit-direct loop circuit and indirect loop circuit-are theoretically distinguished, and the methods to avoid such mistake are proposed. Finally, PVC production and vinyl acetate production are adopted to demonstrate the methods. PMID:18197463

Cao, Kai; Feng, Xiao

2008-12-01

354

Shape-Time Photography  

E-print Network

We introduce a new method to describe, in a single image, changes in shape over time. We acquire both range and image information with a stationary stereo camera. From the pictures taken, we display a composite image ...

Freeman, William T.

2002-01-10

355

Shaped Offset QPSK Capacity  

E-print Network

In this work we compute the capacities and the pragmatic capacities of military-standard shaped-offset quadrature phase-shift keying (SOQPSK-MIL) and aeronautical telemetry SOQPSK (SOQPSK-TG). In the pragmatic approach, ...

Sahin, Cenk

2012-08-31

356

Electrostatically shaped membranes  

NASA Technical Reports Server (NTRS)

Disclosed is a method and apparatus for electrostatically shaping a membrane suitable for use in antennas or the like, comprising an electrically conductive thin membrane where the periphery of said membrane is free to move in at least one direction, a first charge on the electrically conductive thin membrane to electrostatically stiffen the membrane, a second charge which shapes the electrostatically stiffened thin membrane and a restraint for limiting the movement of at least one point of the thin membrane relative to the second charge. Also disclosed is a method and apparatus for adaptively controlling the shape of the thin membrane by sensing the shape of the membrane and selectively controlling the first and second charge to achieve a desired performance characteristic of the membrane.

Silverberg, Larry M. (Inventor)

1994-01-01

357

Interactives: 3D Shapes  

NSDL National Science Digital Library

How much liquid can that glass hold? What are the dimensions of that package that's heading off to a friend overseas? Answers to both of those questions (and many more) can be found in this lovely interactive feature on 3D shapes created by experts at the Annenberg Media group. Visitors to this site will learn about three-dimensional geometric shapes by examining a number of objects through a number of interactive exercises and games. The materials are divided into four sections, which include "3D Shapes", "Surface Area & Volume", and "Platonic Solids". The "Platonic Solids" area is quite a bit of fun, as visitors will get the opportunity to print out foldable shapes such as a tetrahedron. A short fifteen question quiz that tests the materials covered by these various activities rounds out the site.

358

Shape optimization of electromagnet  

Microsoft Academic Search

The paper deals with finding the optimal shape of the electromagnet by changing skew keeper and skew pole shoe of the electromagnet so as to obtain maximum tensile force. The solution used numerical methods, especially the program COMSOL.

S. Zajaczek; L. Skr?iva?nek; L. Iva?nek

2010-01-01

359

Shapes and Poetry  

NSDL National Science Digital Library

In this math lesson, learners read the poem "Shapes" from "A Light in the Attic" by Shel Silverstein. Then, learners create their own illustration of the poem. In this lesson, learners explore geometric figures and positional words.

Mathematics, National C.

2008-01-01

360

Aerodynamic shape optimization of arbitrary hypersonic vehicles  

NASA Technical Reports Server (NTRS)

A new method was developed to optimize, in terms of aerodynamic wave drag minimization, arbitrary (nonaxisymmetric) hypersonic vehicles in modified Newtonian flow, while maintaining the initial volume and length of the vehicle. This new method uses either a surface fitted Fourier series to represent the vehicle's geometry or an independent point motion algorithm. In either case, the coefficients of the Fourier series or the spatial locations of the points defining each cross section were varied and a numerical optimization algorithm based on a quasi-Newton gradient search concept was used to determine the new optimal configuration. Results indicate a significant decrease in aerodynamic wave drag for simple and complex geometries at relatively low CPU costs. In the case of a cone, the results agreed well with known analytical optimum ogive shapes. The procedure is capable of accepting more complex flow field analysis codes.

Dulikravich, George S.; Sheffer, Scott G.

1991-01-01

361

Shaped-conical radiation pattern performance of the backfire quadrifilar helix  

Microsoft Academic Search

It is shown that shaped-conical radiation patterns can be realized by extending the resonant fractional-turn quadrifilar helix to an integral number of turns, i.e., the radiated energy can be concentrated into a cone with the gain decreasing from a maximum at the edge of the cone to a local minimum at the center. This pattern shape is near optimum for

C. C. Kilgus

1975-01-01

362

Tight and loose shapes in flat entangled dense polymers  

E-print Network

We investigate the effects of topological constraints (entanglements) on two dimensional polymer loops in the dense phase, and at the collapse transition (Theta point). Previous studies have shown that in the dilute phase the entangled region becomes tight, and is thus localised on a small portion of the polymer. We find that the entropic force favouring tightness is considerably weaker in dense polymers. While the simple figure-eight structure, created by a single crossing in the polymer loop, localises weakly, the trefoil knot and all other prime knots are loosely spread out over the entire chain. In both the dense and Theta conditions, the uncontracted knot configuration is the most likely shape within a scaling analysis. By contrast, a strongly localised figure-eight is the most likely shape for dilute prime knots. Our findings are compared to recent simulations.

Andreas Hanke; Ralf Metzler; Paul G. Dommersnes; Yacov Kantor; Mehran Kardar

2003-07-24

363

[Optimum soil water supply range of Malus pumila].  

PubMed

By means of the determination of net photosynthetic rate and transpiration rate of the leaves of seven-year field and two-year spotted Malus pumila (Goldspur) under different soil water contents and illumination and calculation of water use efficiency (WUE), the optimum soil water supply range of Malus pumila was determined. The results showed that because photosynthetic advantageous radiation (PAR) and soil water content (SWC) decided the value of photosynthetic rate and transpiration rate of Goldspur, thus they influenced the value of WUE. The response of WUE to illumination had relations with soil water. When SWC was 10% (50% of field capacity-FC) or so, the maximum of WUE was the highest value among all the soil water treatment and reached about 230 mumolCO2.g-1H2O. When the water supply was adequate (SWC > 15%), the maximum was only 160 mumolCO2.g-1H2O or so, the difference between each SWC level was not obvious and simulated curve fundamentally overlapped, although WUE decreased slowly after reached the maximum. The variation of WUE with SWC had relations with illumination. WUE was the highest while PAR was in the range of 500-1,000 mumol.m-2.s-1). Because the state of soil water decided the values of stomatic resistance (RS) and leaf water potential, RS and psi 1 also had influence on the changes of WUE. When RS and psi 1 were respectively 2.0 s.cm-1 and -3.0 MPa, WUE was the highest, but Pn was relatively low, which was not good to the normal growth and fruitage of trees. From the overall consideration of WUE, Pn and Tr, the scopes of RS and psi 1 were 2-6 s.cm-1 and -2.1 approximately -1.65 MPa, respectively, which not only guaranteed the normal photosynthesis of Goldspur, but also benefited the increase of WUE. The scope of the corresponding SWC was 11%-15%, which was equal to 55%-75% of FC and this scope could be used as theoretical index of field water supply for Goldspur. PMID:14733015

Wang, Keqin

2003-09-01

364

UWB communication receiver feedback loop  

DOEpatents

A novel technique and structure that maximizes the extraction of information from reference pulses for UWB-TR receivers is introduced. The scheme efficiently processes an incoming signal to suppress different types of UWB as well as non-UWB interference prior to signal detection. Such a method and system adds a feedback loop mechanism to enhance the signal-to-noise ratio of reference pulses in a conventional TR receiver. Moreover, sampling the second order statistical function such as, for example, the autocorrelation function (ACF) of the received signal and matching it to the ACF samples of the original pulses for each transmitted bit provides a more robust UWB communications method and system in the presence of channel distortions.

Spiridon, Alex (Palo Alto, CA); Benzel, Dave (Livermore, CA); Dowla, Farid U. (Castro Valley, CA); Nekoogar, Faranak (San Ramon, CA); Rosenbury, Erwin T. (Castro Valley, CA)

2007-12-04

365

PREFACE: Loops 11: Non-Perturbative / Background Independent Quantum Gravity  

NASA Astrophysics Data System (ADS)

Loops 11 The international conference LOOPS'11 took place in Madrid from the 23-28 May 2011. It was hosted by the Instituto de Estructura de la Materia (IEM), which belongs to the Consejo Superior de Investigaciones Cient?ficas (CSIC). Like previous editions of the LOOPS meetings, it dealt with a wealth of state-of-the-art topics on Quantum Gravity, with special emphasis on non-perturbative background-independent approaches to spacetime quantization. The main topics addressed at the conference ranged from the foundations of Quantum Gravity to its phenomenological aspects. They encompassed different approaches to Loop Quantum Gravity and Cosmology, Polymer Quantization, Quantum Field Theory, Black Holes, and discrete approaches such as Dynamical Triangulations, amongst others. In addition, this edition celebrated the 25th anniversary of the introduction of the now well-known Ashtekar variables and the Wednesday morning session was devoted to this silver jubilee. The structure of the conference was designed to reflect the current state and future prospects of research on the different topics mentioned above. Plenary lectures that provided general background and the 'big picture' took place during the mornings, and the more specialised talks were distributed in parallel sessions during the evenings. To be more specific, Monday evening was devoted to Shape Dynamics and Phenomenology Derived from Quantum Gravity in Parallel Session A, and to Covariant Loop Quantum Gravity and Spin foams in Parallel Session B. Tuesday's three Parallel Sessions dealt with Black Hole Physics and Dynamical Triangulations (Session A), the continuation of Monday's session on Covariant Loop Quantum Gravity and Spin foams (Session B) and Foundations of Quantum Gravity (Session C). Finally, Thursday and Friday evenings were devoted to Loop Quantum Cosmology (Session A) and to Hamiltonian Loop Quantum Gravity (Session B). The result of the conference was very satisfactory and enlightening. Not only was it a showroom for the research currently being carried out by many groups throughout the world, but there was also a permanent look towards the future. During these days, the CSIC Campus witnessed many scientific conversations triggered by the interaction amongst the people and groups that participated in LOOPS'11 Madrid and which, in many cases, will crystallise into new results and advances in the field. The conference would not have been possible without the generous help of a number of national and international institutions. The organizers would like to acknowledge the financial support provided by the Spanish Ministry of Science and Innovation (Ministerio de Ciencia e Innovación), the Spanish Research Council, CSIC (Consejo Superior de Investigaciones Cient?ficas), The BBVA Foundation (Fundación BBVA), The CONSOLIDER-CPAN project, the Spanish Society for Gravitation and Relativity (SEGRE), The Universidad Carlos III of Madrid (UC3M), and the European Science Foundation (ESF). The ESF, through the Quantum Gravity and Quantum Geometry network, provided full support for a number of young participants that have contributed to these proceedings: Dario Benedetti (Albert Einstein Institute, Potsdam, Germany), Norbert Bodendorfer (Institute for Theoretical Physics III, FAU Erlangen Nürnberg, Germany), Mariam Bouhmadi López (CENTRA, Centro Multidisciplinar de Astrof?sica, Lisbon), Timothy Budd (Institute for Theoretical Physics, Utrecht University, The Netherlands), Miguel Campiglia (Institute for Gravitation and the Cosmos, Penn State University, USA), Gianluca Delfino (School of Mathematical Sciences, University of Nottingham, UK), Maite Dupuis (Institute for Theoretical Physics III, FAU Erlangen Nürnberg, Germany), Micha? Dziendzikowski (Institute of Theoretical Physics, Warsaw University, Poland), Muxin Han (Centre de Physique Théorique de Luminy, Marseille, France), Philipp Höhn (Institute for Theoretical Physics, Utrecht University, The Netherlands), Jacek Puchta (Centre de Physique Théorique de Luminy, Marseille, France), James Ryan (Albe

Mena Marugán, Guillermo A.; Barbero G, J. Fernando; Garay, Luis J.; Villaseñor, Eduardo J. S.; Olmedo, Javier

2012-05-01

366

Control-Loop Design for Three-loop Voltage Regulators With Adaptive Voltage Position Control  

Microsoft Academic Search

This paper proposes the control loop design for the three-loop voltage regulator (VR) to achieve adaptive voltage position control. A y-parameters model for the VR with current-mode controlled active droop method is introduced to simplify the original three-loop system to a two-loop system. Therefore the compensation network design becomes much simple. Following the theoretical analysis, simulation and experimental results demonstrate

Xiaogao Xie; Junming Zhang; Yu Ma; Zhaoming Qian

2006-01-01

367

MutS mediates heteroduplex loop formation by a translocation mechanism.  

PubMed Central

Interaction of Escherichia coli MutS and MutL with heteroduplex DNA has been visualized by electron microscopy. In a reaction dependent on ATP hydrolysis, complexes between a MutS dimer and a DNA heteroduplex are converted to protein-stabilized, alpha-shaped loop structures with the mismatch in most cases located within the DNA loop. Loop formation depends on ATP hydrolysis and loop size increases linearly with time at a rate of 370 base pairs/min in phosphate buffer and about 10,000 base pairs/min in the HEPES buffer used for repair assay. These observations suggest a translocation mechanism in which a MutS dimer bound to a mismatch subsequently leaves this site by ATP-dependent tracking or unidimensional movement that is in most cases bidirectional from the mispair. In view of the bidirectional capability of the methyl-directed pathway, this reaction may play a role in determination of heteroduplex orientation. The rate of MutS-mediated DNA loop growth is enhanced by MutL, and when both proteins are present, both are found at the base of alpha-loop structures, and both can remain associated with excision intermediates produced in later stages of the reaction. PMID:9250691

Allen, D J; Makhov, A; Grilley, M; Taylor, J; Thresher, R; Modrich, P; Griffith, J D

1997-01-01

368

Glycoprotein Degradation in the Blind Loop Syndrome  

PubMed Central

Contents obtained from jejunum of normal controls, self-emptying and self-filling blind loop rats were analyzed for the presence of glycoprotein-degrading glycosidases. The blind loop syndrome was documented by the increased fat excretion and slower growth rate of self-filling blind loop rats 6 wk after surgery. With p-nitrophenylglycosides as substrate, the specific activity of ?-N-acetylgalactosaminidase, a potential blood group A destroying glycosidase, was 0.90±0.40 mU/mg of protein. This level was 23-fold higher than the specific activity of normal controls. In partially purified self-filling blind loop contents, the activity of ?-N-acetylgalactosaminidase was 9- to 70-fold higher than activities of self-emptying and normal controls. Antibiotic treatment with chloromycetin and polymyxin decreased 24-fold the glycosidase levels in self-filling blind loops. In experiments with natural substrate, the blood group A titer of a20,000g supernate from normal jejunal homogenates decreased 128-fold after 24-h incubation with blind loop contents. Normal contents failed to diminish the blood group reactivity of the natural substrate. Furthermore, blind loop contents markedly decreased the blood group A titer of isolated brush borders. Incubation between blind loop bacteria and mucosal homogenates or isolated brush borders labeled with d-[U-14C]glucosamine revealed increased production of labeled ether extractable organic acids. Likewise, intraperitoneal injection of d-[U-14C]glucosamine into self-filling blind loop rats resulted in incorporation of the label into luminal short chain fatty acids. These results suggest that glycosidases may provide a mechanism by which blind loop bacteria obtain sugars from intestinal glycoproteins. The released sugars are used and converted by bacteria into energy and organic acids. This use of the host's glycoproteins would allow blind loop bacteria to grow and survive within the lumen independent of exogenous sources. PMID:6257760

Prizont, Roberto

1981-01-01

369

Flow analysis and nozzle-shape optimization for the cold-gas dynamic-spray process  

E-print Network

. For the optimum design of the nozzle, helium as the carrier gas is found to give rise to a substantially higher observations. Keywords: cold-gas dynamic spray process, nozzle design and optimization NOTATION A nozzle crossFlow analysis and nozzle-shape optimization for the cold-gas dynamic-spray process M Grujicic1*, W

Grujicic, Mica

370

Preform tool shape optimization and redesign based on neural network response surface methodology  

Microsoft Academic Search

Preform tool shape optimization using response surface method (RSM) was developed in this work. Neural network approximation model was employed for response surface construction in order to overcome the limitation of quadratic polynomial model in solving non-linear problems. A two-step axisymmetric forging problem was studied as an example using proposed method. Optimum was achieved by using pattern search optimization method

Yu-Cheng Tang; Xiong-Hui Zhou; Jun Chen

2008-01-01

371

Accelerated reaction by loop-mediated isothermal amplification using loop primers  

Microsoft Academic Search

Loop-mediated isothermal amplification (LAMP) is a novel nucleic acid amplification method that amplifies DNA with high specificity, efficiency and rapidity under isothermal conditions using a set of four specially designed primers and a DNA polymerase with strand displacement activity. We have developed a method that accelerates the LAMP reaction by using additional primers, termed loop primers. Loop primers hybridize to

K. Nagamine; T. Hase; T. Notomi

2002-01-01

372

Quantitation of interactions between two DNA loops demonstrates loop domain insulation in E. coli cells.  

PubMed

Eukaryotic gene regulation involves complex patterns of long-range DNA-looping interactions between enhancers and promoters, but how these specific interactions are achieved is poorly understood. Models that posit other DNA loops-that aid or inhibit enhancer-promoter contact-are difficult to test or quantitate rigorously in eukaryotic cells. Here, we use the well-characterized DNA-looping proteins Lac repressor and phage ? CI to measure interactions between pairs of long DNA loops in E. coli cells in the three possible topological arrangements. We find that side-by-side loops do not affect each other. Nested loops assist each other's formation consistent with their distance-shortening effect. In contrast, alternating loops, where one looping element is placed within the other DNA loop, inhibit each other's formation, thus providing clear support for the loop domain model for insulation. Modeling shows that combining loop assistance and loop interference can provide strong specificity in long-range interactions. PMID:25288735

Priest, David G; Kumar, Sandip; Yan, Yan; Dunlap, David D; Dodd, Ian B; Shearwin, Keith E

2014-10-21

373

3D Sun Loop Tracer: A Tool for Stereoscopy of Coronal Loops for NASA's STEREO Mission  

Microsoft Academic Search

Stereoscopy and triangulation can be used to determine the three-dimensional geometry of coronal loops seen in simultaneous images from the two STEREO spacecraft. Here we demonstrate a new tool, 3D Sun Loop Tracer (SLT), which uses stereoscopy to determine the 3D structure of a loop that can be identified in both images. SLT proceeds in several stages. First, the user

P. C. Liewer; E. M. Dejong; J. R. Hall; J. J. Lorre; P. Sheth

2005-01-01

374

3D Sun Loop Tracer: A Tool for Stereoscopy of Coronal Loops for NASA's STEREO Mission  

Microsoft Academic Search

Stereoscopy and triangulation can be used to determine the three-dimensional geometry of coronal loops seen in simultaneous images from the two STEREO spacecraft. Here we demonstrate a new tool 3D Sun Loop Tracer (SLT) that uses stereoscopy to determine the 3D structure of a loop that can be identified in both images. SLT proceeds in several stages. First, the user

J. R. Hall; P. Sheth; E. Dejong; J. Lorre; P. Liewer

2004-01-01

375

Relationship between Optimum Temperatures for Growth and Preferred Temperatures for the Young of Four Fish Species  

Microsoft Academic Search

Optimum temperatures for growth and temperature preference were estimated and compared for young striped bass Morone saxatilis, white perch Morone americana, white catfish Ictalurus catus, and spottail shiner Notropis hudsonius to determine how closely behavioral thermoregulation corresponded to optimal growth temperatures. Differences between the final preferenda and the optimum growth temperatures were less than 2 C. The percentage of preferred

Robert L. Kellogg; James J. Gift

1983-01-01

376

Optimum detailed design of reinforced concrete continuous beams using Genetic Algorithms  

Microsoft Academic Search

This paper presents the application of Genetic Algorithms for the optimum detailed design of reinforced concrete continuous beams based on Indian Standard specifications. The produced optimum design satisfies the strength, serviceability, ductility, durability and other constraints related to good design and detailing practice. While most of the approaches reported in the literature consider the steel reinforcement as a variable, the

V. Govindaraj; J. V. Ramasamy

2005-01-01

377

Optimum design by computer of power electronic transformers and d.c. chokes  

Microsoft Academic Search

The computer programs described provide a tool to the power-electronic circuit designer for the rapid optimum design of transformers and dc chokes, without magnetic expertise and judgemental decisions on the critical parameters of maximum flux density and current density, and without interpolation of graphical data on core loss. The programs eliminate the iteration of virtually complete designs for credible optimum

W. J. Muldoon

1987-01-01

378

A novel optimum operating point tracker of the solar cell power supply system  

Microsoft Academic Search

When the solar array is used as an input power source, the optimum operating point tracker is often employed to exploit more effectively the solar array as an electric power source and to obtain the maximum electric power at all times even when the light intensity and environmental temperature of the solar array are varied. Usually, the optimum operating point

K. Kobayashi; Hirofumi Matsuo; Yutaka Sekine

2004-01-01

379

Optimum vegetation characteristics, assimilation, and transpiration during a dry season: 1. Model description  

Microsoft Academic Search

This paper presents a model to predict optimum vegetation characteristics in water stressed conditions. Starting point is the principle of homeostasis of water flow through the soil-vegetation-atmosphere continuum. Combining this with a biochemical model for photosynthesis, a relationship between photosynthetic capacity, stomatal regulation, and hydraulic properties of the vegetation is derived. Optimum photosynthetic capacity and internal carbon dioxide concentration are

C. van der Tol; A. G. C. A. Meesters; A. J. Dolman; M. J. Waterloo

2008-01-01

380

Comment on `Optimum depth of the information pit on the data surface of a compact disk'  

E-print Network

Comment on `Optimum depth of the information pit on the data surface of a compact disk' SJOERD. investigated the question of optimum pit depth in optical disc read-out. Data on such a disc (e.g. CD or DVD

381

OPTIMUM DESIGN OF SEDIMENTATION TANKS BASED ON SETTLING CHARACTERISTICS OF KARACHI TANNERY WASTES  

Microsoft Academic Search

A study was carried out in a specially designed settling column to investigate the settling characteristics of effluents arising from Karachi tanneries. The Jar-tests were conducted to determine the optimum dosage of coagulants such as potash alum and ferric chloride to maximize the removal of suspended solids (S.S) from the wastes. For alum, the optimum dosage was found to be

Waseem Akhtar; Muhammad Rauf; Iqbal Ali; Nayeemuddin

1997-01-01

382

Optimum design of sedimentation tanks based on setting characteristics of Karachi tannery wastes  

Microsoft Academic Search

A study was carried out in a specially designed settling column to investigate the settling characteristics of effluents arising from Karachi tanneries. The Jar-tests were conducted to determine the optimum dosage of coagulants such as potash alum and ferric chloride to maximize the removal of suspended solids (S.S) from the wastes. For alumn, the optimum dosage was found to be

Waseem Akhtar; Muhammad Rauf; Iqbal Ali

1997-01-01

383

Strehl ratio and optimum focus of high-numerical-aperture beams  

E-print Network

Strehl ratio and optimum focus of high-numerical-aperture beams Augustus J.E.M. Janssena , Sven van with a high numerical aperture (NA) that optimizes its Strehl ratio in the case of small aberrations up to the 'just' diffraction-limited value (Strehl ratio 0.80). The optimum focus setting deviates from the one

384

Optimum design of bridges with superelastic-friction base isolators against near-field earthquakes  

NASA Astrophysics Data System (ADS)

The seismic response of a multi-span continuous bridge isolated with novel superelastic-friction base isolator (S-FBI) is investigated under near-field earthquakes. The isolation system consists of a flat steel-Teflon sliding bearing and a superelastic NiTi shape memory alloy (SMA) device. Sliding bearings limit the maximum seismic forces transmitted to the superstructure to a certain value that is a function of friction coefficient of sliding interface. Superelastic SMA device provides restoring capability to the isolation system together with additional damping characteristics. The key design parameters of an S-FBI system are the natural period of the isolated, yielding displacement of SMA device, and the friction coefficient of the sliding bearings. The goal of this study is to obtain optimal values for each design parameter by performing sensitivity analyses of the isolated bridge. First, a three-span continuous bridge is modeled as a two-degrees-of-freedom with S-FBI system. A neuro-fuzzy model is used to capture rate-dependent nonlinear behavior of SMA device. A time-dependent method which employs wavelets to adjust accelerograms to match a target response spectrum with minimum changes on the other characteristics of ground motions is used to generate ground motions used in the simulations. Then, a set of nonlinear time history analyses of the isolated bridge is performed. The variation of the peak response quantities of the isolated bridge is shown as a function of design parameters. Also, the influence of temperature variations on the effectiveness of S-FBI system is evaluated. The results show that the optimum design of the isolated bridge with S-FBI system can be achieved by a judicious specification of design parameters.

Ozbulut, Osman E.; Hurlebaus, Stefan

2010-04-01

385

Technical Seminar "Shape Memory Alloys"  

NASA Video Gallery

Shape memory alloys are a unique group of materials that remember their original shape and return to that shape after being strained. How could the aerospace, automotive, and energy exploration ind...

386

Symmetry constrained shape evolution in shape manifolds for shape based retrieval  

Microsoft Academic Search

Shape manifolds provide mathematically consistent and rigorous characterization of shapes and their variability. Continuous boundary based representations offer advantages of unambiguous reproduction of shape compared to landmark based methods and obviates the need for manual selection of landmark points. An important drawback of continuous shape representations is their inability to constrain shape to meaningful deformation modes, thus making template based

Saurav Basu; Scott T. Acton

2010-01-01

387

A linear quadratic Gaussian with loop transfer recovery proximity operations autopilot for spacecraft. M.S. Thesis - MIT  

NASA Technical Reports Server (NTRS)

An automatic control scheme for spacecraft proximity operations is presented. The controller is capable of holding the vehicle at a prescribed location relative to a target, or maneuvering it to a different relative position using straight line-of-sight translations. The autopilot uses a feedforward loop to initiate and terminate maneuvers, and for operations at nonequilibrium set-points. A multivariate feedback loop facilitates precise position and velocity control in the presence of sensor noise. The feedback loop is formulated using the Linear Quadratic Gaussian (LQG) with Loop Transfer Recovery (LTR) design procedure. Linear models of spacecraft dynamics, adapted from Clohessey-Wiltshire Equations, are augmented and loop shaping techniques are applied to design a target feedback loop. The loop transfer recovery procedure is used to recover the frequency domain properties of the target feedback loop. The resulting compensator is integrated into an autopilot which is tested in a high fidelity Space Shuttle Simulator. The autopilot performance is evaluated for a variety of proximity operations tasks envisioned for future Shuttle flights.

Chen, George T.

1987-01-01

388

Distributed Loop Computer Networks: A Survey  

Microsoft Academic Search

Distributed loop computer networks are extensions of the ring networks and are widelyused in the design and implementation of local area networks and parallel processingarchitectures. We give a survey of recent results on this class of interconnection networks.We pay special attention to the actual computation of the minimum diameterand the construction of loop networks which can achieve this optimal number.

Jean-claude Bermond; Francesc Comellas; D. Frank Hsu

1995-01-01

389

Accident analysis of HANARO fuel test loop.  

National Technical Information Service (NTIS)

Steady state fuel test loop will be equipped in HANARO to obtain the development and betterment of advanced fuel and materials through the irradiation tests. The HANARO fuel test loop was designed to match the CANDU and PWR fuel operating conditions. The ...

J. Kim, D. Chi

1998-01-01

390

Looping: Creating Elementary School Communities. Fastback 478.  

ERIC Educational Resources Information Center

Looping, a multi-year teaching assignment whereby a teacher remains with the same group of children for more than one grade, is designed to meet the individual needs of students and improve student learning. This booklet describes the practice of looping in American schools. The booklet details the underlying theories supporting the practice and…

Little, Thomas S.; Little, Lynn Priest

391

Ground Loops for Heat Pumps and Refrigeration  

E-print Network

Ground loops are used for water source heat pumps. Refrigeration can be put on a ground loop. Water-cooled condensing units are more efficient than air-cooled, and they can be put indoors. Indoor location makes piping for desuperheater hot water...

Braud, H. J.

1986-01-01

392

Characterizing and Modeling Coronal Loop Blobs  

NASA Astrophysics Data System (ADS)

The solar corona is dominated by loop-like structures. Most of these loops seem to be quite quiescent with a near uniform emission along their length. However, a small sample of loops show bright, transient blobs flowing across their length. Unlike the falling blobs observed in EIT by De Groof et. al (2003), AIA has recorded blobs that rise from the base of the loop and transverse the entire loop length. A sporadic and short lived heating event is thought to initiate the launch of a blob. However, these heating events are thought by some to be common in the lower solar atmosphere, so it is unclear why only a small subset of loops should show these blobs. In this work we perform a statistical analysis on the physical properties of blobs (size, speed, intensity profile, etc.) that transverse the entire loop length. We then model a series of loops under various heating scenarios and geometrical configurations in order to determine which parameters play a role in blob formation.

Winter, Henry D.; Tembe, Mita; Reeves, Kathy; McCauley, Patrick I

2014-06-01

393

Towards hardware implementation of loop subdivision  

Microsoft Academic Search

We present a novel algorithm to evaluate and render Loop subdivision surfaces. The algorithm exploits the fact that Loop subdivision surfaces are piecewise polynomial and uses the forward difference technique for efficiently computing uniform samples on the limit surface. The main advantage of our algorithm is that it only requires a small and constant amount of memory that does not

Stephan Bischoff; Leif P. Kobbelt; Hans-Peter Seidel

2000-01-01

394

Symplectic Action Around Loops In Ham( M )  

Microsoft Academic Search

Let Ham(M) be the group of Hamiltonian symplectomorphisms of a quantizable, compact, symplectic manifold (M, ?). We prove the existence of an action integral around loops in Ham(M), and determine the value of this action integral on particular loops when the manifold is a coadjoint orbit.

Andrés Viña; Avda Calvo Sotelo

2004-01-01

395

Hook-And-Loop Metal Fastener  

NASA Technical Reports Server (NTRS)

Proposed fastener includes metal loops and hooks repeatedly put together and pulled apart like Velcro (or equivalent) plastic fastener. Strip of hooks stamped from sheet of metal, and tip of each hook bent at right angle to root. Many such strips arrayed in parallel to form hook half of fastener. Each hook twists and bends as loop pulled away.

Sawaf, Bernard; Ross, J. P.; Harvey, Andrew C.

1994-01-01

396

Insights from the TMI-2 LOOP analysis  

SciTech Connect

As part of the program to modify the technical specifications of Three Mile Island Unit 2 (TMI-2) to reflect the current condition of the plant, an analysis to determine the probability of loss of off-site power (LOOP) was performed. Insights derived from this analysis should be useful in other LOOP analyses.

Deininger, F.W.; Weaver, W.W.

1986-01-01

397

Is LoopCo the answer?  

Microsoft Academic Search

Proposals have been made to separate BT vertically into two parts: an access network (LoopCo) providing services to all operators, and a core network. The aim is to counter discriminatory behaviour by an integrated firm. The paper reviews similar approaches to separation in UK utilities and establishes criteria for evaluating the LoopCo proposal. It suggests that technological developments are moving

Martin Cave

2002-01-01

398

Spring control of wire harness loops  

NASA Technical Reports Server (NTRS)

Negator spring control guides wire harness between movable and fixed structure. It prevents electrical wire harness loop from jamming or being severed as wire moves in response to changes in position of aircraft rudder. Spring-loaded coiled cable controls wire loop regardless of rudder movement.

Curcio, P. J.

1979-01-01

399

Duality between Wilson loops and gluon amplitudes  

E-print Network

An intriguing new duality between planar MHV gluon amplitudes and light-like Wilson loops in N=4 super Yang-Mills is investigated. We extend previous checks of the duality by performing a two-loop calculation of the rectangular and pentagonal Wilson loop. Furthermore, we derive an all-order broken conformal Ward identity for the Wilson loops and analyse its consequences. Starting from six points, the Ward identity allows for an arbitrary function of conformal invariants to appear in the expression for the Wilson loop. We compute this function at six points and two loops and discuss its implications for the corresponding gluon amplitude. It is found that the duality disagrees with a conjecture for the gluon amplitudes by Bern et al. A recent calculation by Bern et al indeed shows that the latter conjecture breaks down at six gluons and at two loops. By doing a numerical comparison with their results we find that the duality between gluon amplitudes and Wilson loops is preserved. This review is based on the author's PhD thesis and includes developments until May 2008.

J. M. Henn

2009-03-03

400

Nonglobal logarithms at three loops, four loops, five loops, and beyond  

NASA Astrophysics Data System (ADS)

We calculate the coefficients of the leading nonglobal logarithms for the hemisphere mass distribution analytically at 3, 4, and 5 loops at large Nc. We confirm that the integrand derived with the strong-energy-ordering approximation and fixed-order iteration of the Banfi-Marchesini-Syme (BMS) equation agree. Our calculation exploits a hidden PSL(2,R) symmetry associated with the jet directions, apparent in the BMS equation after a stereographic projection to the Poincaré disk. The required integrals have an iterated form, leading to functions of uniform transcendentality. This allows us to extract the coefficients, and some functional dependence on the jet directions, by computing the symbols and coproducts of appropriate expressions involving classical and Goncharov polylogarithms. Convergence of the series to a numerical solution of the BMS equation is also discussed.

Schwartz, Matthew D.; Zhu, Hua Xing

2014-09-01

401

Modeling of loops in protein structures.  

PubMed Central

Comparative protein structure prediction is limited mostly by the errors in alignment and loop modeling. We describe here a new automated modeling technique that significantly improves the accuracy of loop predictions in protein structures. The positions of all nonhydrogen atoms of the loop are optimized in a fixed environment with respect to a pseudo energy function. The energy is a sum of many spatial restraints that include the bond length, bond angle, and improper dihedral angle terms from the CHARMM-22 force field, statistical preferences for the main-chain and side-chain dihedral angles, and statistical preferences for nonbonded atomic contacts that depend on the two atom types, their distance through space, and separation in sequence. The energy function is optimized with the method of conjugate gradients combined with molecular dynamics and simulated annealing. Typically, the predicted loop conformation corresponds to the lowest energy conformation among 500 independent optimizations. Predictions were made for 40 loops of known structure at each length from 1 to 14 residues. The accuracy of loop predictions is evaluated as a function of thoroughness of conformational sampling, loop length, and structural properties of native loops. When accuracy is measured by local superposition of the model on the native loop, 100, 90, and 30% of 4-, 8-, and 12-residue loop predictions, respectively, had <2 A RMSD error for the mainchain N, C(alpha), C, and O atoms; the average accuracies were 0.59 +/- 0.05, 1.16 +/- 0.10, and 2.61 +/- 0.16 A, respectively. To simulate real comparative modeling problems, the method was also evaluated by predicting loops of known structure in only approximately correct environments with errors typical of comparative modeling without misalignment. When the RMSD distortion of the main-chain stem atoms is 2.5 A, the average loop prediction error increased by 180, 25, and 3% for 4-, 8-, and 12-residue loops, respectively. The accuracy of the lowest energy prediction for a given loop can be estimated from the structural variability among a number of low energy predictions. The relative value of the present method is gauged by (1) comparing it with one of the most successful previously described methods, and (2) describing its accuracy in recent blind predictions of protein structure. Finally, it is shown that the average accuracy of prediction is limited primarily by the accuracy of the energy function rather than by the extent of conformational sampling. PMID:11045621

Fiser, A.; Do, R. K.; Sali, A.

2000-01-01

402

Mass Inflation in the Loop Black Hole  

E-print Network

In classical general relativity the Cauchy horizon within a two-horizon black hole is unstable via a phenomenon known as mass inflation, in which the mass parameter (and the spacetime curvature) of the black hole diverges at the Cauchy horizon. Here we study this effect for loop black holes -- quantum gravitationally corrected black holes from loop quantum gravity -- whose construction alleviates the $r=0$ singularity present in their classical counterparts. We use a simplified model of mass inflation, which makes use of the generalized DTR relation, to conclude that the Cauchy horizon of loop black holes indeed results in a curvature singularity similar to that found in classical black holes. The DTR relation is of particular utility in the loop black hole because it does not directly rely upon Einstein's field equations. We elucidate some of the interesting and counterintuitive properties of the loop black hole, and corroborate our results using an alternate model of mass inflation due to Ori.

Eric G. Brown; Robert B. Mann; Leonardo Modesto

2011-04-15

403

Conformal radii for conformal loop ensembles  

E-print Network

The conformal loop ensembles CLE(k), defined for k in [8/3, 8], are random collections of loops in a planar domain which are conjectured scaling limits of the O(n) loop models. We calculate the distribution of the conformal radii of the nested loops surrounding a deterministic point. Our results agree with predictions made by Cardy and Ziff and by Kenyon and Wilson for the O(n) model. We also compute the expectation dimension of the CLE(k) gasket, which consists of points not surrounded by any loop, to be 2-(8-k)(3k-8)/32k, which agrees with the fractal dimension given by Duplantier for the O(n) model gasket.

Oded Schramm; Scott Sheffield; David B. Wilson

2006-11-22

404

REVIEWS OF TOPICAL PROBLEMS: Coronal magnetic loops  

NASA Astrophysics Data System (ADS)

The goal of this review is to outline some new ideas in the physics of coronal magnetic loops, the fundamental structural elements of the atmospheres of the Sun and flaring stars, which are involved in phenomena such as stellar coronal heating, flare energy release, charged particle acceleration, and the modulation of optical, radio, and X-ray emissions. The Alfvén-Carlqvist view of a coronal loop as an equivalent electric circuit allows a good physical understanding of loop processes. Describing coronal loops as MHD-resonators explains various ways in which flaring emissions from the Sun and stars are modulated, whereas modeling them by magnetic mirror traps allows one to describe the dynamics and emission of high-energy particles. Based on these approaches, loop plasma and fast particle parameters are obtained and models for flare energy release and stellar corona heating are developed.

Zaitsev, Valerii V.; Stepanov, Alexander V.

2008-11-01

405

Looping probabilities of elastic chains: a path integral approach.  

PubMed

We consider an elastic chain at thermodynamic equilibrium with a heat bath, and derive an approximation to the probability density function, or pdf, governing the relative location and orientation of the two ends of the chain. Our motivation is to exploit continuum mechanics models for the computation of DNA looping probabilities, but here we focus on explaining the novel analytical aspects in the derivation of our approximation formula. Accordingly, and for simplicity, the current presentation is limited to the illustrative case of planar configurations. A path integral formalism is adopted, and, in the standard way, the first approximation to the looping pdf is obtained from a minimal energy configuration satisfying prescribed end conditions. Then we compute an additional factor in the pdf which encompasses the contributions of quadratic fluctuations about the minimum energy configuration along with a simultaneous evaluation of the partition function. The original aspects of our analysis are twofold. First, the quadratic Lagrangian describing the fluctuations has cross-terms that are linear in first derivatives. This, seemingly small, deviation from the structure of standard path integral examples complicates the necessary analysis significantly. Nevertheless, after a nonlinear change of variable of Riccati type, we show that the correction factor to the pdf can still be evaluated in terms of the solution to an initial value problem for the linear system of Jacobi ordinary differential equations associated with the second variation. The second novel aspect of our analysis is that we show that the Hamiltonian form of these linear Jacobi equations still provides the appropriate correction term in the inextensible, unshearable limit that is commonly adopted in polymer physics models of, e.g. DNA. Prior analyses of the inextensible case have had to introduce nonlinear and nonlocal integral constraints to express conditions on the relative displacement of the end points. Our approximation formula for the looping pdf is of quite general applicability as, in contrast to most prior approaches, no assumption is made of either uniformity of the elastic chain, nor of a straight intrinsic shape. If the chain is uniform the Jacobi system evaluated at certain minimum energy configurations has constant coefficients. In such cases our approximate pdf can be evaluated in an entirely explicit, closed form. We illustrate our analysis with a planar example of this type and compute an approximate probability of cyclization, i.e., of forming a closed loop, from a uniform elastic chain whose intrinsic shape is an open circular arc. PMID:21230517

Cotta-Ramusino, Ludovica; Maddocks, John H

2010-11-01

406

Laser beam shaping techniques  

SciTech Connect

Industrial, military, medical, and research and development applications of lasers frequently require a beam with a specified irradiance distribution in some plane. A common requirement is a laser profile that is uniform over some cross-section. Such applications include laser/material processing, laser material interaction studies, fiber injection systems, optical data image processing, lithography, medical applications, and military applications. Laser beam shaping techniques can be divided into three areas: apertured beams, field mappers, and multi-aperture beam integrators. An uncertainty relation exists for laser beam shaping that puts constraints on system design. In this paper the authors review the basics of laser beam shaping and present applications and limitations of various techniques.

DICKEY,FRED M.; WEICHMAN,LOUIS S.; SHAGAM,RICHARD N.

2000-03-16

407

Venn Diagram Shape Sorter  

NSDL National Science Digital Library

In this activity, students practice placing big and small shapes into Venn diagrams depending on the rules of the diagram. Students can either specify these rules or have the applet assign the rules so they can try to figure them out by placing shapes in the diagram. This activity allows students to explore Venn diagrams and the terms associated with set theory. This activity includes supplemental materials, including background information about the topics covered, a description of how to use the application, and exploration questions for use with the java applet.

2010-01-01

408

Shapes of d Orbitals  

NSDL National Science Digital Library

Shapes of d Orbitals shows the d orbitals in an axis set. Running the mouse over an orbital reveals the "name" of that orbital. This is good practice for helping students link the name of an orbital to the orientation.Shapes of d Orbitals has a link to D Orbitals in an Octahedral Ligand Field. Here the user may click on the name of any one of the d orbitals to obtain a larger 3-dimensional image. The images are rotatable and scalable. Orbital phase is shown by the different colors.

409

Shape Aftereffects Reflect Shape Constancy Operations: Appearance Matters  

ERIC Educational Resources Information Center

One of the oldest known visual aftereffects is the shape aftereffect, wherein looking at a particular shape can make subsequent shapes seem distorted in the opposite direction. After viewing a narrow ellipse, for example, a perfect circle can look like a broad ellipse. It is thought that shape aftereffects are determined by the dimensions of…

Storrs, Katherine R.; Arnold, Derek H.

2013-01-01

410

Interference Lattice-based Loop Nest Tilings for Stencil Computations  

NASA Technical Reports Server (NTRS)

A common method for improving performance of stencil operations on structured multi-dimensional discretization grids is loop tiling. Tile shapes and sizes are usually determined heuristically, based on the size of the primary data cache. We provide a lower bound on the numbers of cache misses that must be incurred by any tiling, and a close achievable bound using a particular tiling based on the grid interference lattice. The latter tiling is used to derive highly efficient loop orderings. The total number of cache misses of a code is the sum of (necessary) cold misses and misses caused by elements being dropped from the cache between successive loads (replacement misses). Maximizing temporal locality is equivalent to minimizing replacement misses. Temporal locality of loop nests implementing stencil operations is optimized by tilings that avoid data conflicts. We divide the loop nest iteration space into conflict-free tiles, derived from the cache miss equation. The tiling involves the definition of the grid interference lattice an equivalence class of grid points whose images in main memory map to the same location in the cache-and the construction of a special basis for the lattice. Conflicts only occur on the boundaries of the tiles, unless the tiles are too thin. We show that the surface area of the tiles is bounded for grids of any dimensionality, and for caches of any associativity, provided the eccentricity of the fundamental parallelepiped (the tile spanned by the basis) of the lattice is bounded. Eccentricity is determined by two factors, aspect ratio and skewness. The aspect ratio of the parallelepiped can be bounded by appropriate array padding. The skewness can be bounded by the choice of a proper basis. Combining these two strategies ensures that pathologically thin tiles are avoided. They do not, however, minimize replacement misses per se. The reason is that tile visitation order influences the number of data conflicts on the tile boundaries. If two adjacent tiles are visited successively, there will be no replacement misses on the shared boundary. The iteration space may be covered with pencils larger than the size of the cache while avoiding data conflicts if the pencils are traversed by a scanning-face method. Replacement misses are incurred only on the boundaries of the pencils, and the number of misses is minimized by maximizing the volume of the scanning face, not the volume of the tile. We present an algorithm for constructing the most efficient scanning face for a given grid and stencil operator. In two dimensions it is based on a continued fraction algorithm. In three dimensions it follows Voronoi's successive minima algorithm. We show experimental results of using the scanning face, and compare with canonical loop orderings.

VanderWijngaart, Rob F.; Frumkin, Michael

2000-01-01

411

Electrical engineering and nontechnical design variables of multiple inductive loop systems for auditoriums.  

PubMed

This research analyzed both engineering and nontechnical issues involved in the use of Induction Loop Amplification (ILA) devices in auditoriums or large gathering places for hard-of-hearing individuals. A variety of parameters need to be taken into account to determine an optimal shape/configuration for the ILA device. In many cases, an optimal configuration is different from those proposed for classroom use (Ross, 1969; Hodgson, 1986; Clevenger, 1992). Experimental results were obtained for a double-loop configuration in such a setting (a university gymnasium/auditorium in this case). The results demonstrate that a double-loop configuration is a viable possibility for auditorium use. Several variables using this configuration were examined, and experimentation was done. Various implications, including consequent nontechnical issues specific to this application, are discussed as well. Technical and nontechnical aspects of the ILA configuration need to be examined together when designing an optimal system. PMID:15304441

Alterovitz, Gil

2004-01-01

412

Noncoding transcription by alternative RNA polymerases dynamically regulates an auxin-driven chromatin loop.  

PubMed

The eukaryotic epigenome is shaped by the genome topology in three-dimensional space. Dynamic reversible variations in this epigenome structure directly influence the transcriptional responses to developmental cues. Here, we show that the Arabidopsis long intergenic noncoding RNA (lincRNA) APOLO is transcribed by RNA polymerases II and V in response to auxin, a phytohormone controlling numerous facets of plant development. This dual APOLO transcription regulates the formation of a chromatin loop encompassing the promoter of its neighboring gene PID, a key regulator of polar auxin transport. Altering APOLO expression affects chromatin loop formation, whereas RNA-dependent DNA methylation, active DNA demethylation, and Polycomb complexes control loop dynamics. This dynamic chromatin topology determines PID expression patterns. Hence, the dual transcription of a lincRNA influences local chromatin topology and directs dynamic auxin-controlled developmental outputs on neighboring genes. This mechanism likely underscores the adaptive success of plants in diverse environments and may be widespread in eukaryotes. PMID:25018019

Ariel, Federico; Jegu, Teddy; Latrasse, David; Romero-Barrios, Natali; Christ, Aurélie; Benhamed, Moussa; Crespi, Martin

2014-08-01

413

Visualization of individual DNA loops and a map of loop domains in the human dystrophin gene.  

PubMed

The organization of the human dystrophin gene into loop domains has been studied using two different experimental approaches: excision of DNA loops mediated by nuclear matrix-bound topoisomerase II and in situ hybridization of different probes with histone-depleted nuclei (nuclear halos). Our objective was to examine if the DNA loops mapped by this biochemical approach coincide with loops visualized by microscopy. The results obtained using both approaches were in good agreement. Eight loops separated by attachment regions of different length were mapped in the upstream part (up to exon 54) of the gene by topoisomerase II-mediated excision. One of these loops was then directly visualized by in situ hybridization of the corresponding bacmid clone with nuclear halos. This is the first direct demonstration that a DNA domain mapped as a loop using a biochemical approach corresponds to a loop visible on cytological preparations. The validity of this result and of the whole map of loop domains was confirmed by in situ hybridization using probes derived from other attachment regions or loops mapped by topoisomerase II-mediated cleavage; these probes hybridized on the core or halo region, respectively, of nuclear halos. Our results demonstrate that a single transcription unit may be organized into several loops and that DNA loop attachment regions may be fairly long. Three out of four replication origins mapped in this gene co-localize with loop attachment regions, and the major deletion hot spot is harbored in an attachment region. These results strongly suggest that partitioning of genomic DNA into specific loops attached to a skeletal structure is a characteristic feature of eukaryotic chromosome organization in interphase. PMID:15087487

Iarovaia, Olga V; Bystritskiy, Andrey; Ravcheev, Dmitrii; Hancock, Ronald; Razin, Sergey V

2004-01-01

414

Loop Heat Pipe Development Overview  

NASA Astrophysics Data System (ADS)

Over the last 4 years, the loop heat pipe (LHP) technology has been under development by this institute, focusing on future applications for this passive thermal control device, specially related to instruments' thermal control in satellites. Such a development has been focused on designing, manufacturing, assembling, charging and testing LHPs for Space applications using acetone as working fluid. Several procedures were specially conceived during the development program, which resulted in reliable apparatuses that have been extensively tested for potential applications. Repeatability on the processes used during the manufacturing of the LHPs was established as the key parameter to qualify this technology, as well as suppliers and techniques for charging and testing procedures. As a result, several LHPs were manufactured and are operational presenting reliable results related to the thermal control, according to the parameters established by the project. In parallel, two mathematical models were developed based on the experimental data gathered in laboratory conditions, which were then validated and have been applied on the design of LHPs for Earth orbit operation.

Riehl, Roger R.; dos Santos, Nadjara

2008-01-01

415

Towards Loop Quantum Supergravity (LQSG)  

NASA Astrophysics Data System (ADS)

Should nature be supersymmetric, then it will be described by Quantum Supergravity at least in some energy regimes. The currently most advanced description of Quantum Supergravity and beyond is Superstring Theory/M-Theory in 10/11 dimensions. String Theory is a top-to-bottom approach to Quantum Supergravity in that it postulates a new object, the string, from which classical Supergravity emerges as a low energy limit. On the other hand, one may try more traditional bottom-to-top routes and apply the techniques of Quantum Field Theory. Loop Quantum Gravity (LQG) is a manifestly background independent and non-perturbative approach to the quantisation of classical General Relativity, however, so far mostly without supersymmetry. The main obstacle to the extension of the techniques of LQG to the quantisation of higher dimensional Supergravity is that LQG rests on a specific connection formulation of General Relativity which exists only in D+1=4 dimensions. In this Letter we introduce a new connection formulation of General Relativity which exists in all space-time dimensions. We show that all LQG techniques developed in D+1=4 can be transferred to the new variables in all dimensions and describe how they can be generalised to the new types of fields that appear in Supergravity theories as compared to standard matter, specifically Rarita-Schwinger and p-form gauge fields.

Bodendorfer, N.; Thiemann, T.; Thurn, A.

2012-05-01

416

Threshold hadronic event shapes with effective field theory  

SciTech Connect

Hadronic event shapes, that is, event shapes at hadron colliders, could provide a great way to test both standard and nonstandard theoretical models. However, they are significantly more complicated than event shapes at e{sup +}e{sup -} colliders, involving multiple hard directions, multiple channels, and multiple color structures. In this paper, hadronic event shapes are examined with soft-collinear effective theory (SCET) by expanding around the dijet limit. A simple event shape, threshold thrust, is defined. This observable is global and has no free parameters, making it ideal for clarifying how resummation of hadronic event shapes can be done in SCET. Threshold thrust is calculated at next-to-leading fixed order (NLO) in SCET and resummed to next-to-next-to-leading logarithmic (NNLL) accuracy. The scale-dependent parts of the soft function are shown to agree with what is expected from general observations, and the factorization formula is explicitly shown to be renormalization group invariant to 1-loop. Although threshold thrust is not itself expected to be phenomenologically interesting, it can be modified into a related observable which allows the jet p{sub T} distribution to be calculated and resummed to NNLL+NLO accuracy. As in other processes, one expects resummation to be important even for moderate jet momenta due to dynamical threshold enhancement. A general discussion of threshold enhancement and nonglobal logs in hadronic event shapes is also included.

Kelley, Randall; Schwartz, Matthew D. [Center for the Fundamental Laws of Nature, Harvard University, Cambridge, Massachusetts 02138 (United States)

2011-02-01

417

Bending and Twisting the Embryonic Heart: A Computational Model for C-Looping Based on Realistic Geometry  

NASA Astrophysics Data System (ADS)

The morphogenetic process of cardiac looping transforms the straight heart tube into a curved tube that resembles the shape of the future four-chambered heart. Although great progress has been made in identifying the molecular and genetic factors involved in looping, the physical mechanisms that drive this process have remained poorly understood. Recent work, however, has shed new light on this complicated problem. After briefly reviewing the current state of knowledge, we propose a relatively comprehensive hypothesis for the mechanics of the first phase of looping, termed c-looping, as the straight heart tube deforms into a c-shaped tube. According to this hypothesis, differential hypertrophic growth in the myocardium supplies the main forces that cause the heart tube to bend ventrally, while regional growth and contraction in the omphalomesenteric veins (primitive atria) and compressive loads exerted by the splanchnopleuric membrane drive rightward torsion. A computational model based on realistic embryonic heart geometry is used to test this hypothesis. The behavior of the model is in reasonable agreement with available experimental data from control and perturbed embryos, offering support for our hypothesis. The results also suggest, however, that several other mechanisms contribute secondarily to normal looping, and we speculate that these mechanisms play backup roles when looping is perturbed. Finally, some outstanding questions are discussed for future study.

Shi, Yunfei; Yao, Jiang; Young, Jonathan; Fee, Judy; Perucchio, Renato; Taber, Larry

2014-08-01

418

Development of Non-Optimum Factors for Launch Vehicle Propellant Tank Bulkhead Weight Estimation  

NASA Technical Reports Server (NTRS)

Non-optimum factors are used during aerospace conceptual and preliminary design to account for the increased weights of as-built structures due to future manufacturing and design details. Use of higher-fidelity non-optimum factors in these early stages of vehicle design can result in more accurate predictions of a concept s actual weights and performance. To help achieve this objective, non-optimum factors are calculated for the aluminum-alloy gores that compose the ogive and ellipsoidal bulkheads of the Space Shuttle Super-Lightweight Tank propellant tanks. Minimum values for actual gore skin thicknesses and weld land dimensions are extracted from selected production drawings, and are used to predict reference gore weights. These actual skin thicknesses are also compared to skin thicknesses predicted using classical structural mechanics and tank proof-test pressures. Both coarse and refined weights models are developed for the gores. The coarse model is based on the proof pressure-sized skin thicknesses, and the refined model uses the actual gore skin thicknesses and design detail dimensions. To determine the gore non-optimum factors, these reference weights are then compared to flight hardware weights reported in a mass properties database. When manufacturing tolerance weight estimates are taken into account, the gore non-optimum factors computed using the coarse weights model range from 1.28 to 2.76, with an average non-optimum factor of 1.90. Application of the refined weights model yields non-optimum factors between 1.00 and 1.50, with an average non-optimum factor of 1.14. To demonstrate their use, these calculated non-optimum factors are used to predict heavier, more realistic gore weights for a proposed heavy-lift launch vehicle s propellant tank bulkheads. These results indicate that relatively simple models can be developed to better estimate the actual weights of large structures for future launch vehicles.

Wu, K. Chauncey; Wallace, Matthew L.; Cerro, Jeffrey A.

2012-01-01

419

Optimum Projection Angle for Attaining Maximum Distance in a Soccer Punt Kick  

PubMed Central

To produce the greatest horizontal distance in a punt kick the ball must be projected at an appropriate angle. Here, we investigated the optimum projection angle that maximises the distance attained in a punt kick by a soccer goalkeeper. Two male players performed many maximum-effort kicks using projection angles of between 10° and 90°. The kicks were recorded by a video camera at 100 Hz and a 2 D biomechanical analysis was conducted to obtain measures of the projection velocity, projection angle, projection height, ball spin rate, and foot velocity at impact. The player’s optimum projection angle was calculated by substituting mathematical equations for the relationships between the projection variables into the equations for the aerodynamic flight of a soccer ball. The calculated optimum projection angles were in agreement with the player’s preferred projection angles (40° and 44°). In projectile sports even a small dependence of projection velocity on projection angle is sufficient to produce a substantial shift in the optimum projection angle away from 45°. In the punt kicks studied here, the optimum projection angle was close to 45° because the projection velocity of the ball remained almost constant across all projection angles. This result is in contrast to throwing and jumping for maximum distance, where the projection velocity the athlete is able to achieve decreases substantially with increasing projection angle and so the optimum projection angle is well below 45°. Key points The optimum projection angle that maximizes the distance of a punt kick by a soccer goalkeeper is about 45°. The optimum projection angle is close to 45° because the projection velocity of the ball is almost the same at all projection angles. This result is in contrast to throwing and jumping for maximum distance, where the optimum projection angle is well below 45° because the projection velocity the athlete is able to achieve decreases substantially with increasing projection angle. PMID:24149315

Linthorne, Nicholas P.; Patel, Dipesh S.

2011-01-01

420

Size and Shape  

NSDL National Science Digital Library

Size and shape are important in astrobiology. In this activity and slideshow, students observe the importance of relative size and morphology in identifying microscopic structures when viewed with the scanning electron microscope. This activity is part of an astrobiology guide called the "Fingerprints of Life" which contains background information for students, worksheets, extension activities, suggested assessments, and alignment to standards.

421

Nuclear shape isomers  

NASA Astrophysics Data System (ADS)

We calculate potential-energy surfaces as functions of spheroidal (?2), hexadecapole (?4), and axial-asymmetry (?) shape coordinates for 7206 nuclei from A=31 to A=290. We tabulate the deformations and energies of all minima deeper than 0.2 MeV and of the saddles between all pairs of minima. The tabulation is terminated at N=160. Our study is based on the FRLDM macroscopic-microscopic model defined in ATOMIC DATA AND NUCLEAR DATA TABLES [P. Möller, J.R. Nix, W.D. Myers, W.J. Swiatecki, At. Data Nucl. Data Tables 59 (1995) 185]. We also present potential-energy contour plots versus ?2 and ? for 1224 even-even nuclei in the region studied. We can identify nuclei for which a necessary condition for shape isomers occurs, namely multiple minima in the calculated potential-energy surface. We find that the vast majority of nuclear shape isomers occur in the A=80 region, the A=100 region, and in a more extended region centered around 208Pb. A calculated region of shape isomers that has so far not been extensively explored is the region of neutron-deficient actinides "north-east" of 208Pb.

Möller, P.; Sierk, A. J.; Bengtsson, R.; Sagawa, H.; Ichikawa, T.

2012-03-01

422

Shaped charge jet particulation  

Microsoft Academic Search

An analytical model was developed to predict the breakup time of the jet from a shaped charge liner. The model is based on three presumptions. First, a kinematic expression for the breakup time; second, expression related to plastic stability; and finally, a material-based constitutive equation relating the stress, strain, strain rate, and temperature. In other words, the jet from a

William P. Walters; Richard L. Summers

1994-01-01

423

Volume and Shapes  

NSDL National Science Digital Library

This one and a half minute video shows a classroom of students working on an activity that utilizes linking cubes to demonstrate the relationship between three-dimensional shapes and their volume. Included with the video is a background essay on volume and discussion questions.

2006-01-01

424

Sounds Exaggerate Visual Shape  

ERIC Educational Resources Information Center

While perceiving speech, people see mouth shapes that are systematically associated with sounds. In particular, a vertically stretched mouth produces a /woo/ sound, whereas a horizontally stretched mouth produces a /wee/ sound. We demonstrate that hearing these speech sounds alters how we see aspect ratio, a basic visual feature that contributes…

Sweeny, Timothy D.; Guzman-Martinez, Emmanuel; Ortega, Laura; Grabowecky, Marcia; Suzuki, Satoru

2012-01-01

425

A Perceptual Shape Descriptor  

Microsoft Academic Search

We represent a two dimensional object silhouette by a one dimensional descriptor, which preserves the perceptual structure of its shape. The proposed descriptor is based on the moments of the angles between the bearings of a point on the boundary, in a set of neighborhood systems. At each point on the boundary, the angle between a pair of bearings is

Nafiz Arica; Fatos T. Yarman-vural

2002-01-01

426

Orbital Shape Representations.  

ERIC Educational Resources Information Center

Discusses the use of orbital shapes for instructional purposes, emphasizing that differences between polar, contour, and three-dimensional plots must be made clear to students or misconceptions will occur. Also presents three-dimensional contour surfaces for the seven 4f atomic orbitals of hydrogen and discusses their computer generation. (JN)

Kikuchi, Osamu; Suzuki, Keizo

1985-01-01

427

Shape potential of rock  

Microsoft Academic Search

This paper scientifically investigates the relevance and merit of industrial approaches to improving the shape of crushed rock in the aggregate industry. Of particular interest is the degree to which the mechanisms which are occurring within the crusher machine can alter what is generally considered to be inherent patterns of breakage for certain rock types.Simple experiments have been conducted that

C. Briggs; C. M. Evertsson

1998-01-01

428

Iterative structure of finite loop integrals  

NASA Astrophysics Data System (ADS)

In this paper we develop further and refine the method of differential equations for computing Feynman integrals. In particular, we show that an additional iterative structure emerges for finite loop integrals. As a concrete non-trivial example we study planar master integrals of light-by-light scattering to three loops, and derive analytic results for all values of the Mandelstam variables s and t and the mass m. We start with a recent proposal for defining a basis of loop integrals having uniform transcendental weight properties and use this approach to compute all planar two-loop master integrals in dimensional regularization. We then show how this approach can be further simplified when computing finite loop integrals. This allows us to discuss precisely the subset of integrals that are relevant to the problem. We find that this leads to a block triangular structure of the differential equations, where the blocks correspond to integrals of different weight. We explain how this block triangular form is found in an algorithmic way. Another advantage of working in four dimensions is that integrals of different loop orders are interconnected and can be seamlessly discussed within the same formalism. We use this method to compute all finite master integrals needed up to three loops. Finally, we remark that all integrals have simple Mandelstam representations.

Caron-Huot, Simon; Henn, Johannes M.

2014-06-01

429

Bootstrapping an NMHV amplitude through three loops  

E-print Network

We extend the hexagon function bootstrap to the next-to-maximally-helicity-violating (NMHV) configuration for six-point scattering in planar \\${\\cal N}=4\\$ super-Yang-Mills theory at three loops. Constraints from the \\$\\bar{Q}\\$ differential equation, from the operator product expansion (OPE) for Wilson loops with operator insertions, and from multi-Regge factorization, lead to a unique answer for the three-loop ratio function. The three-loop result also predicts additional terms in the OPE expansion, as well as the behavior of NMHV amplitudes in the multi-Regge limit at one higher logarithmic accuracy (NNLL) than was used as input. Both predictions are in agreement with recent results from the flux-tube approach. We also study the multi-particle factorization of multi-loop amplitudes for the first time. We find that the function controlling this factorization is purely logarithmic through three loops. We show that a function \\$U\\$, which is closely related to the parity-even part of the ratio function \\$V\\$, is remarkably simple; only five of the nine possible final entries in its symbol are non-vanishing. We study the analytic and numerical behavior of both the parity-even and parity-odd parts of the ratio function on simple lines traversing the space of cross ratios \\$(u,v,w)\\$, as well as on a few two-dimensional planes. Finally, we present an empirical formula for $V$ in terms of elements of the coproduct of the six-gluon MHV remainder function \\$R_6\\$ at one higher loop, which works through three loops for \\$V\\$ (four loops for \\$R_6\\$).

Lance J. Dixon; Matt von Hippel

2014-08-07

430

The optimum levels of the thermal protection of residential buildings under climatic conditions of Russia  

NASA Astrophysics Data System (ADS)

The present paper reports the results of determining the optimum values of the resistance of building envelopes to heat transfer for both existing and newly constructed buildings for regions of Russia with different climatic conditions. An analysis for the sensitivity of obtained optimum solutions to changes in external factors has been made. The potential of energy saving in both the existing housing stock and in newly constructed buildings due to the improvement of thermal protection performance of buildings to the optimum level has been determined.

Filippov, S. P.; Dil'man, M. D.; Ionov, M. S.

2013-11-01

431

Developmental Differences in Shape Processing  

ERIC Educational Resources Information Center

Considerable evidence indicates that shape similarity plays a major role in object recognition, identification and categorization. However, little is known about shape processing and its development. Across four experiments, we addressed two related questions. First, what makes objects similar in shape? Second, how does the processing of shape

Sera, Maria D.; Gordon Millett, Katherine

2011-01-01

432

Shape memory alloy thaw sensors  

DOEpatents

A sensor permanently indicates that it has been exposed to temperatures exceeding a critical temperature for a predetermined time period. An element of the sensor made from shape memory alloy changes shape when exposed, even temporarily, to temperatures above the Austenitic temperature of the shape memory alloy. The shape change of the SMA element causes the sensor to change between two readily distinguishable states.

Shahinpoor, Mohsen (Albuquerque, NM); Martinez, David R. (Albuquerque, NM)

1998-01-01

433

How Do You Make Loops and Switches?  

NSDL National Science Digital Library

Students learn how to program using loops and switches. They see how loops enable us to easily and efficiently tell a computer to keep repeating an operation. They also see that switches permit programs to follow different instructions based on whether or not preconditions are fulfilled. Using the LEGO® MINDSTORMS® NXT robots, sensors and software, student pairs perform three mini programming activities using loops and switches individually, and then combined. With practice, they incorporate these tools into their programming skill sets in preparation for the associated activity. A PowerPoint® presentation, pre/post quizzes and worksheet are provided.

GK-12 Program, Computational Neurobiology Center,

434

Black holes with current loops revisited  

E-print Network

The electromagnetic field around a Kerr black hole inside a current loop is sometimes used as the basis of a toy model for discussing the properties of particle orbits near astrophysical black holes. The motivation for the present paper is to correct the published solution to Maxwell's equations with a charged current loop. Dipole approximations and closed-form expressions in the extreme Kerr limit are also presented. Using the corrected solution, it turns out that imposing a vanishing electromotive force produces a loop with a potential which is finite everywhere outside the black hole. Ring solutions can be combined into solutions with multiple rings or current discs.

Ian G Moss

2011-02-15

435

Capillary-Pumped Heat-Transfer Loop  

NASA Technical Reports Server (NTRS)

New type of capillary-pumped heat-transfer loop primes itself at startup. Removes substantial quantities of heat like that generated by people and equipment in rooms and vehicles. Creates continuous path for its working fluid; both vapor and liquid move in same direction. Key element in operation of loop is formation of slugs of liquid, condensed from vapor and moved along loop by vapor bubbles before and after it. Both evaporator and condenser contain axial arteries carrying water. Heat entering evaporator from heat source provides energy for transport of fluid and heat. Dimensions in inches.

1989-01-01

436

DNA looping: the consequences and its control  

E-print Network

The formation of DNA loops by proteins and protein complexes is ubiquitous to many fundamental cellular processes, including transcription, recombination, and replication. Here we review recent advances in understanding the properties of DNA looping in its natural context and how they propagate to the cellular behavior through gene regulation. The results of connecting the molecular properties with cellular physiology indicate that looping of DNA in vivo is much more complex and easier than predicted from current models and reveals a wealth of previously unappreciated details.

Leonor Saiz; Jose M. G. Vilar

2006-09-26

437

Closed loop recycling of lead/acid batteries  

NASA Astrophysics Data System (ADS)

The traditional lead/acid battery is a recycleable product, irrespective whether it is of an automotive, traction or standby design. The product benefits from the traditional lead metallurgy that has been developed for both primary (mines) and secondary (recycling) smelting. Secondary smelting accounts for 60% of total lead production in Europe, and this market lead the most effectively metal. In secondary smelters, scrapped batteries are crushed and smelted. The polypropylene from the boxes is recycled to produce secondary plastic for battery, automotive, or other miscellaneous uses. The lead metal is refined to be re-used in the battery industry. The acid is retreated. Recycling requires a collection network. The lead/acid battery benefits from the traditional collection network that has been established for scrap-iron and non-ferrous metal scrap. In Western Europe, the recycling rate for scrapped batteries is estimated to be 80 to 90%. All participants in the battery recycling loop agree that the process must be a clean cycle for it to be credible. The collection organization is improving the quality of storage and transportation, especially with regard to the acid that can only be neutralized in correctly-controlled facilities, generally located at the smelters. The smelters themselves tend, through local regulations, to run at the optimum level of protection of the environment.

Bied-Charreton, B.

438

Defect-detection methods in the position-control loop of numerically controlled machine tools  

Microsoft Academic Search

A promising means of improving machine-tool reliability is diagnostics of the actual state of the components and organization of maintenance and repair. Effective diagnostics and timely adoption of preventive measures may reduce repair costs by 20?25%, which makes a significant difference to plant economics. Machine-tool performance depends considerably on the supply drives in the control loops for the shaping motion

G. V. Shadskii; V. S. Sal’nikov; A. N. Kazimirov

2008-01-01

439

Robust, optimal subsonic airfoil shapes  

NASA Technical Reports Server (NTRS)

Method system, and product from application of the method, for design of a subsonic airfoil shape, beginning with an arbitrary initial airfoil shape and incorporating one or more constraints on the airfoil geometric parameters and flow characteristics. The resulting design is robust against variations in airfoil dimensions and local airfoil shape introduced in the airfoil manufacturing process. A perturbation procedure provides a class of airfoil shapes, beginning with an initial airfoil shape.

Rai, Man Mohan (Inventor)

2008-01-01

440

Nanoreinforced shape memory polyurethane  

NASA Astrophysics Data System (ADS)

Shape memory polymers (SMPs) are functional materials, which find applications in a broad range of temperature sensing elements and biological micro-electro-mechanical systems (MEMS). These polymers are capable of fixing a transient shape and recovering to their original shape after a series of thermo-mechanical treatments. Generally, these materials are thermoplastic segmented polyurethanes composed of soft segments, usually formed by a polyether macroglycol, and hard segments formed from the reaction of a diisocyanate with a low molecular mass diol. The hard segment content is a key parameter to control the final properties of the polymer, such as rubbery plateau modulus, melting point, hardness, and tensile strength. The long flexible soft segment largely controls the low temperature properties, solvent resistance, and weather resistance properties. The morphology and properties of polyurethanes (PU) are greatly influenced by the ratio of hard and soft block components and the average block lengths. However, in some applications, SMPs may not generate enough recovery force to be useful. The reinforcement of SMPs using nanofillers represents a novel approach of enhancing the performance of these materials. The incorporation of these fillers into SMPs can produce performance enhancements (particularly elastic modulus) at small nanoparticle loadings (˜1-2 wt %). An optimal performance of nanofiller-polymer nanocomposites requires uniform dispersion of filler in polymers and good interfacial adhesion. The addition of nanofillers like cellulose nanofibers (CNF), conductive cellulose nanofibers (C-CNF), and carbon nanotubes (CNTs) allows for the production of stiffer materials with deformation capacity comparable to that of the unfilled polymer. Additionally, the use of conductive nanoreinforcements such as C-CNF and CNTs leads to new pathways for actuation of the shape memory effect. During this work, thermoplastic shape memory polyurethanes were synthesized with varying chemical composition and molecular weight. This was achieved by controlling the moles of reactants used, by using polyols with different molecular weights, and by using different diisocyanates. Using these controls, polymer matrices with different but controlled structures were synthesized and then reinforced with CNF, C-CNF, and CNTs in order to study the influence of chemical structure and polymer-nanoreinforcement interactions on polymer nanocomposite morphology, thermal and mechanical properties, and shape memory behavior.

Richardson, Tara Beth

441

Simulations of magnetic hysteresis loops at high temperatures  

NASA Astrophysics Data System (ADS)

The kinetic Monte-Carlo algorithm as well as standard micromagnetics are used to simulate MH loops of high anisotropy magnetic recording media at both short and long time scales over a wide range of temperatures relevant to heat-assisted magnetic recording. Microscopic parameters, common to both methods, were determined by fitting to experimental data on single-layer FePt-based media that uses the Magneto-Optic Kerr effect with a slow sweep rate of 700 Oe/s. Saturation moment, uniaxial anisotropy, and exchange constants are given an intrinsic temperature dependence based on published atomistic simulations of FePt grains with an effective Curie temperature of 680 K. Our results show good agreement between micromagnetics and kinetic Monte Carlo results over a wide range of sweep rates. Loops at the slow experimental sweep rates are found to become more square-shaped, with an increasing slope, as temperature increases from 300 K. These effects also occur at higher sweep rates, typical of recording speeds, but are much less pronounced. These results demonstrate the need for accurate determination of intrinsic thermal properties of future recording media as input to micromagnetic models as well as the sensitivity of the switching behavior of thin magnetic films to applied field sweep rates at higher temperatures.

Plumer, M. L.; van Ek, J.; Whitehead, J. P.; Fal, T. J.; Mercer, J. I.

2014-09-01

442

Closed-loop control of flexible space shuttle manipulator  

NASA Astrophysics Data System (ADS)

This paper develops a new approach to dynamic modeling and closed-loop vibration damping control of a Hermes type multi-link flexible manipulator for 2-dimensional motion of the vehicle/ manipulator system in the pitch plane. The flexible links are modeled by replacing them by rigid members and fictitious rotational springs at the servo motor joints to give a dynamically equivalent system. Linear equations of motion are derived by Lagrangian formulation for small motions relative to an arbitrary baseline configuration and eigenvalue analysis shows that mode shapes and frequencies are relatively insensitive to the angle between the two main manipulator arms. Closed-loop modal control is then performed by velocity feedback from the active servo joints to the shoulder joint and a simple, stable control law is derived for the non-collocated sensor-actuator system. The emphasis is on a simplified approach which facilitates physical interpretation of vehicle/manipulator dynamics and control, and which can be used to verify more comprehensive multibody computer codes.

Kirk, C. L.; Doengi, F. L.

1993-09-01

443

Closed-loop vibration control of flexible space shuttle manipulator  

NASA Astrophysics Data System (ADS)

This paper develops a new approach to dynamic modelling and closed-loop vibration damping control of a Hermes type multi-link flexible manipulator for two-dimensional vibratory motion of the vehicle/manipulator system in the pitch plane. The flexible links are modelled by replacing them by rigid members and fictitious rotational springs at the servo motor joints to give a dynamically equivalent system. Linear equations of motion are derived by Lagrangian formulation for small motions relative to an arbitrary baseline configuration and eigenvalue analysis shows that mode shapes and frequencies are relatively insensitive to the angle between the two main manipulator arms. Closed-loop modal control is then performed by velocity feedback from the active servo joints to the shoulder joint and a simple, stable damping control law is derived for the non-collocated sensor-actuator system. The emphasis is on a simplified approach which facilitates physical interpretation of vehicle/manipulator dynamics and control, and which can be used to verify more comprehensive multibody computer codes.

Kirk, Colin L.; Doengi, Frank L.

444

Control of interface shape of cadmium zinc telluride grown via an electrodynamic gradient freeze furnace  

Microsoft Academic Search

We consider the feasibility of closed-loop control to control the interface shape of cadmium zinc telluride (CZT) grown via an electrodynamic gradient freeze (EDG) furnace. A simple proportional control algorithm is applied to a quasi-steady-state model to control the interface shape by adjusting the thermal gradient of the furnace temperatures. Three scenarios are enacted: actuation along the entire external boundary,

Lisa Lun; Andrew Yeckel; Jeffrey J. Derby; Prodromos Daoutidis

2007-01-01

445

A MONTE CARLO SEQUENTIAL ESTIMATION OF POINT PROCESS OPTIMUM FILTERING FOR BRAIN MACHINE INTERFACES  

E-print Network

1 A MONTE CARLO SEQUENTIAL ESTIMATION OF POINT PROCESS OPTIMUM FILTERING FOR BRAIN MACHINE Monte Carlo Sequential Estimation for Point Processes.................................................29 Simulation of Monte Carlo Sequential Estimation on Neural Spike Train Decoding............32 Interpretation

Slatton, Clint

446

HF (High Frequency) Communications Frequency-Management Procedure for Forecasting the Frequency of Optimum Transmission.  

National Technical Information Service (NTIS)

This report describes a procedure for forecasting the Frequency of Optimum Transmission (FOT) on a high-frequency communications path when the Maximum Observable Frequency (MOF) on another path and an historical record of the correlations of MOFs measured...

M. Daehler

1984-01-01

447

Locally optimum detector for MIMO radar in non-Gaussian clutter  

NASA Astrophysics Data System (ADS)

The optimum Gaussian detector of MIMO radar no longer works well in non-Gaussian clutter environment. Therefore, a locally optimum (LO) detector based on alpha stable distribution is proposed for the signal detection of MIMO radar. The proposed method assumes that the MIMO radar clutter satisfies alpha stable distribution, according to the multiple-input multiple-output characteristics of the signal model, a locally optimum detection statistics for MIMO radar is presented based on the generalized Neyman-Pearson lemma. Both theoretical analysis and simulation results show that the optimum Gaussian detector suffers serious performance degradation in non-Gaussian clutter, whereas the proposed detector can achieve good performance and outperforms the Gaussian detector significantly.

Zhu, Xiaobo; Wang, Shouyong

2011-10-01

448

The parallel execution of DO loops  

Microsoft Academic Search

Methods are developed for the parallel execution of different iterations of a DO loop. Both asynchronous multiprocessor computers and array computers are considered. Practical application to the design of compilers for such computers is discussed.

Leslie Lamport

1974-01-01

449

Roll Loop Aeroservoelasticity in the Time Domain.  

National Technical Information Service (NTIS)

A time domain computer simulation of the roll loop for the YF-16 control system is developed using the Advanced Continuous Simulation Language (ACSL). Using stability derivatives developed during frequency domain studies, the time domain simulation result...

M. A. Cutchins

1977-01-01

450

Speculative parallelization of partially parallel loops  

E-print Network

with even one cross- processor flow dependence because we have to re-execute sequentially. Moreover, the existing, partial parallelism of loops is not exploited. We demonstrate a generalization of the speculative doall parallelization tech- nique, called...

Dang, Francis Hoai Dinh

2009-05-15

451

Supersymmetric Wilson loops in diverse dimensions  

NASA Astrophysics Data System (ADS)

We consider supersymmetric Wilson loops à la Zarembo in planar supersymmetric Yang-Mills theories in diverse dimensions. Using perturbation theory we show that these loops have trivial vacuum expectation values to second order in the 't Hooft coupling. We review the known superspace results which, for specific dimensions, extend this triviality to all orders in the 't Hooft coupling. Using the gauge/gravity correspondence, we construct the explicit dual fundamental string solutions corresponding to these Wilson loops for the case of circular geometry. We find that the regularized action of these string solutions vanishes. We also generalize the framework of calibrated surfaces to prove the vanishing of the regularized action for loops of general geometry. We propose a possible string-side manifestation of the gauge theory generalized Konishi anomaly in seven dimensions.

Agarwal, Abhishek; Young, Donovan

2009-06-01

452

Technical specification of HANARO fuel test loop.  

National Technical Information Service (NTIS)

The design and installation of the irradiation test facility for verification test of the fuel performance are very important in connection with maximization of the utilization of HANARO. HANARO fuel test loop was designed in accordance with the same code...

J. Kim

1998-01-01

453

Loop size in newt lampbrush chromosomes.  

PubMed

Lampbrush chromosome 11 from the newt Taricha granulosa was studied by scanning electron microscopy (SEM) to determine the size of all loops in this bivalent. Measurements with an XY digitizer revealed a mean loop length of 14.9 microns, with a large standard deviation and a skewed distribution toward higher values. The size of the loops at this stage of diplotene extension is similar to that reported in other eukaryotes studies with different approaches. We estimated, from the DNA content of chromosome 11, that between 0.4% and 2.2% of the DNA is found in the loops while the rest of the DNA must remain in the compact chromomeres. PMID:2340758

León, P; Kezer, J

1990-04-01

454

Detecting and escaping infinite loops with jolt  

E-print Network

Infinite loops can make applications unresponsive. Potential problems include lost work or output, denied access to application functionality, and a lack of responses to urgent events. We present Jolt, a novel system for ...

Carbin, Michael James

455

Mathematical Modeling of Loop Heat Pipes  

NASA Technical Reports Server (NTRS)

The primary focus of this study is to model steady-state performance of a Loop Heat Pipe (LHP). The mathematical model is based on the steady-state energy balance equations at each component of the LHP. The heat exchange between each LHP component and the surrounding is taken into account. Both convection and radiation environments are modeled. The loop operating temperature is calculated as a function of the applied power at a given loop condition. Experimental validation of the model is attempted by using two different LHP designs. The mathematical model is tested at different sink temperatures and at different elevations of the loop. Tbc comparison of the calculations and experimental results showed very good agreement (within 3%). This method proved to be a useful tool in studying steady-state LHP performance characteristics.

Kaya, Tarik; Ku, Jentung; Hoang, Triem T.; Cheung, Mark L.

1998-01-01

456

Cosmological evolution of cosmic string loops  

E-print Network

The existence of a scaling evolution for cosmic string loops in an expanding universe is demonstrated for the first time by means of numerical simulations. In contrast with what is usually assumed, this result does not rely on any gravitational back reaction effect and has been observed for loops as small as a few thousandths the size of the horizon. We give the energy and number densities of expected cosmic string loops in both the radiation and matter eras. Moreover, we quantify previous claims on the influence of the network initial conditions and the formation of numerically unresolved loops by showing that they only concern a transient relaxation regime. Some cosmological consequences are discussed.

Christophe Ringeval; Mairi Sakellariadou; Francois Bouchet

2005-11-22

457

A magnetohydrodynamic theory of coronal loop transients  

NASA Technical Reports Server (NTRS)

The physical and geometrical characteristics of solar coronal loop transients are described in an MHD model based on Archimedes' MHD buoyancy force. The theory was developed from interpretation of coronagraphic data, particularly from Skylab. The brightness of a loop is taken to indicate the electron density, and successive pictures reveal the electron enhancement in different columns. The forces which lift the loop off the sun surface are analyzed as an MHD buoyancy force affecting every mass element by imparting an inertial force necessary for heliocentrifugal motion. Thermal forces are responsible for transferring the ambient stress to the interior of the loop to begin the process. The kinematic and hydrostatic buoyancy overcome the gravitational force, and a flux rope can then curve upward, spiralling like a corkscrew with varying cross section around the unwinding solar magnetic field lines.

Yeh, T.

1982-01-01

458

Hierarchical loop detection for mobile outdoor robots  

NASA Astrophysics Data System (ADS)

Loop closing is a fundamental part of 3D simultaneous localization and mapping (SLAM) that can greatly enhance the quality of long-term mapping. It is essential for the creation of globally consistent maps. Conceptually, loop closing is divided into detection and optimization. Recent approaches depend on a single sensor to recognize previously visited places in the loop detection stage. In this study, we combine data of multiple sensors such as GPS, vision, and laser range data to enhance detection results in repetitively changing environments that are not sufficiently explained by a single sensor. We present a fast and robust hierarchical loop detection algorithm for outdoor robots to achieve a reliable environment representation even if one or more sensors fail.

Lang, Dagmar; Winkens, Christian; Häselich, Marcel; Paulus, Dietrich

2012-01-01

459

Optimum Aeroelastic Design of Resonance Type Flapping Wing for Micro Air Vehicles  

NASA Astrophysics Data System (ADS)

The optimum aeroelastic design method for a resonance-type flapping wing for a Micro Air Vehicle (MAV) is presented. It uses Complex Method and 3D Navier-Stokes code to determine the optimum structural and aerodynamic parameters of a 2 DOF flapping wing system. The method is used to design a dragonfly-type MAV, and numerical simulation shows that the designed flapping wings can generate sufficient lift to sustain the weight and sufficient thrust to overcome the body drag.

Isogai, Koji; Kamisawa, Yuichi; Sato, Hiroyuki

460

Life-cycle cost-effective optimum design of steel bridges  

Microsoft Academic Search

This paper address a practical life-cycle cost (LCC) formulation and procedure for the LCC-effective optimum design of steel bridges. A general LCC model for optimum design of steel bridges consists of those of initial cost and direct\\/indirect rehabilitation costs of a steel bridge, including repair\\/replacement costs, loss of contents or fatality and injury losses, road user costs, and indirect socio-economic

Kwang-Min Lee; Hyo-Nam Cho; Young-Min Choi

2004-01-01

461

Optimum Projection Angle for Attaining Maximum Distance in a Rugby Place Kick  

PubMed Central

This study investigated the effect of projection angle on the distance attained in a rugby place kick. A male rugby player performed 49 maximum-effort kicks using projection angles of between 20 and 50°. The kicks were recorded by a video camera at 50 Hz and a 2 D biomechanical analysis was conducted to obtain measures of the projection velocity and projection angle of the ball. The player’s optimum projection angle was calculated by substituting a mathematical expression for the relationship between projection velocity and projection angle into the equations for the aerodynamic flight of a rugby ball. We found that the player’s calculated optimum projection angle (30.6°, 95% confidence limits ± 1.9°) was in close agreement with his preferred projection angle (mean value 30.8°, 95% confidence limits ± 2.1°). The player’s calculated optimum projection angle was also similar to projection angles previously reported for skilled rugby players. The optimum projection angle in a rugby place kick is considerably less than 45° because the projection velocity that a player can produce decreases substantially as projection angle is increased. Aerodynamic forces and the requirement to clear the crossbar have little effect on the optimum projection angle. Key Points The optimum projection angle in a rugby place kick is about 30°. The optimum projection angle is considerably less than 45° because the projection velocity that a player can produce decreases substantially as projection angle is increased. Aerodynamic forces and the requirement to clear the crossbar have little effect on the optimum projection angle. PMID:24570626

Linthorne, Nicholas P.; Stokes, Thomas G.

2014-01-01

462

Optimum multi-plant, multi-supplier production planning for multi-grade petrochemicals  

Microsoft Academic Search

A mixed-integer linear programming model is presented for the optimum planning of multi-plant, multi-supplier, and multi-grade petrochemical production. In the production of multiple grades of a given petrochemical product, the amount of transitional off-spec production depends on the sequencing of different grades. For each time period, the discrete-time model determines the optimum mix of petrochemical grades for each plant, the

Hesham K. Alfares

2009-01-01

463

Optimum bit-by-bit power allocation for minimum distortion transmission  

E-print Network

for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Costas N. Georghiades Committee Members, Scott L. Miller Henry F. Taylor Marina Vannucci Head of Department, Chanan Singh December 2005 Major Subject: Electrical Engineering iii ABSTRACT Optimum... for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Costas N. Georghiades Committee Members, Scott L. Miller Henry F. Taylor Marina Vannucci Head of Department, Chanan Singh December 2005 Major Subject: Electrical Engineering iii ABSTRACT Optimum...

Karaer, Arzu

2007-04-25

464

Methods of determining the optimum state of maturity for picking greenwrap tomatoes  

E-print Network

L IB R AR Y A&M COLLEGE OF TEXAS METHODS OF DETERMINING THE OPTIMUM STATE OF MATURITY FOR PICKING GREENWRAP TOMATOES A Dissertation By HAROLD BENJAMIN SORENSEN Submitted to the Graduate School of the Agricultural and Mechanical College... of Texas in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY May 1955 Major Subject: Horticulture ii METHODS OF DETERMINING THE OPTIMUM STATE OF MATURITT FOR PICKING GRSENWRAP TOMATOES A Dissertation By HAROLD BENJAMIN...

Sorensen, H. B.

2013-10-04

465

Optimum linear combination strategy for an N-channel polarization-sensitive imaging or vision system  

Microsoft Academic Search

Received April 9, 1997; revised manuscript received September 8, 1997; accepted September 16, 1997 The optimum linear combination channels for an N-receptor polarization-sensitive imaging or vision system are found by using a principal-components analysis. The channels that are derived are optimum in the sense that their information contents are uncorrelated when considered over the ensemble of possible polarization signals. For

J. S. Tyo

1998-01-01

466

Locality and Loop Scheduling on NUMA Multiprocessors  

Microsoft Academic Search

An important issue in the parallel execution of loopsis how to partition and schedule the loops onto theavailable processors. While most existing dynamicscheduling algorithms manage load imbalances well,they fail to take locality into account and thereforeperform poorly on parallel systems with non-uniformmemory access times. In this paper, we proposea new loop scheduling algorithm, Locality-based DynamicScheduling (LDS), that exploits locality, anddynamically

Hui Li; Sudarsan Tandri; Michael Stumm; Kenneth C. Sevcik

1993-01-01

467

Polyakov loop potential at finite density  

NASA Astrophysics Data System (ADS)

The Polyakov loop potential serves to distinguish between the confined hadronic and the deconfined quark-gluon plasma phases of QCD. For Nf=2+1 quark flavors with physical masses we determine the Polyakov loop potential at finite temperature and density and extract the location of the deconfinement transition. We find a crossover at small values of the chemical potential running into a critical end-point at ?/T>1.

Fischer, Christian S.; Fister, Leonard; Luecker, Jan; Pawlowski, Jan M.

2014-05-01

468

Quantum Loop Modules and Quantum Spin Chains  

E-print Network

We construct level-0 modules of the quantum affine algebra $\\Uq$, as the $q$-deformed version of the Lie algebra loop module construction. We give necessary and sufficient conditions for the modules to be irreducible. We construct the crystal base for some of these modules and find significant differences from the case of highest weight modules. We also consider the role of loop modules in the recent scheme for diagonalising certain quantum spin chains using their $\\Uq$ symmetry.

D. Altschuler; B. Davies

1993-05-25

469

The Art of Computing Loop Integrals  

E-print Network

A perturbative approach to quantum field theory involves the computation of loop integrals, as soon as one goes beyond the leading term in the perturbative expansion. First I review standard techniques for the computation of loop integrals. In a second part I discuss more advanced algorithms. For these algorithms algebraic methods play an important role. A special section is devoted to multiple polylogarithms. I tried to make these notes self-contained and accessible both to physicists and mathematicians.

Stefan Weinzierl

2006-04-07

470

Local Polyakov loop domains and their fractality  

E-print Network

We discuss properties of local Polyakov loops in the deconfinement transition of SU(3) lattice gauge theory at finite temperature using the fixed scale approach. In particular we study spatial clusters where local Polyakov loops have phases near the same center elements of the gauge group. We present results for various properties of the center clusters, e.g., their percolation probability or their fractality and discuss the physical implications for temperatures below and above the phase transition.

Hans-Peter Schadler; Gergely Endr?di; Christof Gattringer

2013-10-31

471

Closed-loop resuscitation of burn shock.  

PubMed

Fluid therapy for burn shock is adjusted to establish a target level of urinary output. However, the means for adjusting infusion rate are not defined. Our objective was to compare the performance of automated computer-controlled resuscitation with manual control for burn resuscitation. Sheep with a 40% TBSA full-thickness burn, administered under halothane anesthesia, were resuscitated to restore and maintain normal sheep urinary outputs in a target range of 1 to 2 ml/kg per hour over the course of 48 hours using closed-loop resuscitation (n = 10) or manual hourly adjustment of infusion rate (n = 11). The automated closed-loop resuscitation system is based on a proportional-integral-derivative algorithm, which adjusted infusion rate based on continuous monitoring and changes in urinary output. Mean urinary outputs over the course of 48 hours were in target range and were virtually identical at 1.9 +/- 0.5 ml/kg per hour for the closed-loop group and 2.0 +/- 0.7 ml/kg per hour for the technician group. Mean infusion rates and infused volumes also were similar. The closed-loop group exhibited significantly lower hourly variation for both urinary output and infusion rate compared hourly control. Hourly targets were achieved in 41% of the measurements in technician group compared with 48% for the closed-loop group (P = .23). Hourly urinary output in the technician group was undertarget by 25% as opposed to 16% with the closed-loop group (P = .02). Automated closed-loop control of infusion rates after burn injury produced urinary outputs in target ranges with less variation and less under target values than manual hourly adjustments. Closed-loop resuscitation may provide an improvement over current resuscitation regimens. PMID:16679909

Hoskins, Stephen L; Elgjo, Geir Ivar; Lu, Jialung; Ying, Hao; Grady, James J; Herndon, David N; Kramer, George C

2006-01-01

472

Deployable radiator with flexible line loop  

NASA Technical Reports Server (NTRS)

Radiator assembly (10) for use on a spacecraft (12) is provided including at least one radiator panel assembly (26) repeatably movable between a panel stowed position (28) and a panel deployed position (36), at least two flexible lines (40) in fluid communication with the at least one radiator panel assembly (26) and repeatably movable between a stowage loop (42) and a flattened deployed loop (44).

Keeler, Bryan V. (Inventor); Lehtinen, Arthur Mathias (Inventor); McGee, Billy W. (Inventor)

2003-01-01

473

Can Chemical Looping Combustion Use CFB Technology?  

SciTech Connect

Circulating Fluidized Bed (CFB) technology has demonstrated an unparalleled ability to achieve low SO2 and NOx emissions for coal-fired power plants without CO2 capture. Chemical Looping combustion (CLC) is a novel fuel combustion technology which appears as a leading candidate in terms of competitiveness for CO2 removal from flue gas. This presentaion deals with the adaptation of circulating fluidized bed technology to Chemical looping combustion

Gamwo, I.K.

2006-11-01

474