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1

Development of a multiprocessor controlled filament winding machine  

SciTech Connect

Filament winding is a fabrication process for producing reinforced plastic parts of high strength and low weight. Reinforced plastic composites consist of continuous filaments encased in a resin matrix. This synthetic assembly of nonhomogeneous materials produces a material which has many characteristics that are different from more conventional engineering materials. The author looks at the computer control of a filament winding machine using a multiprocessor system.

Skinner, M.L.; Roser, R.R.; Samowitz, K.J.

1983-01-01

2

Filament Winding System.  

National Technical Information Service (NTIS)

An apparatus for winding fine filaments onto stationary long rods includes a supporting base having control mounting and filament mounting regions. The filament winding region includes first and second parallel bearing rods on which are slidably mounted a...

L. E. Sansone B. A. Blakely

1995-01-01

3

Interferometric Fiber Optic Hydrophone Winding Machine.  

National Technical Information Service (NTIS)

A machine for winding, in a selected and consistent manner, a fiber optic filament on a compliant elastomeric mandrel, which assembly responds to acoustic waves by producing variations in diameter and light transmission characteristics of the fiber optic ...

W. G. Matthews T. E. Whitaker

1984-01-01

4

Wind Power Machines.  

National Technical Information Service (NTIS)

Basic aerodynamic features of wind power and wind wheels are discussed. The adaptation of wind power to running machinery is described. Developments in wind power are illustrated, followed by a brief outline of operating properties. (Author)

U. Hutter

1975-01-01

5

Wind power machines  

Microsoft Academic Search

Basic aerodynamic features of wind power and wind wheels are discussed. The adaptation of wind power to running machinery is described. Developments in wind power are illustrated, followed by a brief outline of operating properties.

U. Hutter

1975-01-01

6

Inter-machine scalings of plasma filament electromagnetic features  

NASA Astrophysics Data System (ADS)

Electromagnetic features of turbulent filaments, emerging from turbulent background, have been studied in four different magnetic configurations: the stellarator TJ-II, the Reversed Field Pinch RFX-mod, a device that can be operated also as a ohmic tokamak, and the Simple Magnetized Torus TORPEX. In all cases, direct measurements of both field-aligned current density and vorticity were performed inside the filament. The inter-machine comparison revealed a clear dependence of the filament vorticity upon the local time-averaged ExB flow shear. Furthermore, a wide range of local beta was explored allowing concluding that this parameter plays a fundamental role in the appearance of filament electromagnetic features.

Spolaore, M.; Vianello, N.; Agostini, M.; Cavazzana, R.; de Masi, G.; Martines, E.; Momo, B.; Scaggion, A.; Scarin, P.; Spagnolo, S.; Spizzo, G.; Zuin, M.; Furno, I.; Avino, F.; Fasoli, A.; Theiler, C.; Carralero, D.; Alonso, J. A.; Hidalgo, C.

2012-10-01

7

Preliminary Experiments on Filament Winding Nylon Impregnated Glassfibers (FIT),  

National Technical Information Service (NTIS)

Some preliminary experiments have been conducted on the FIT material, which are nylon pre-impregnated glass-fibers. The advantages of the type of material are mainly focused on manufacturing technology. Filament-winding, flexible braids and weaves are som...

L. G. Meyers

1987-01-01

8

Support vector machines for wind speed prediction  

Microsoft Academic Search

This paper introduces support vector machines (SVM), the latest neural network algorithm, to wind speed prediction and compares their performance with the multilayer perceptron (MLP) neural networks. Mean daily wind speed data from Madina city, Saudi Arabia, is used for building and testing both models. Results indicate that SVM compare favorably with the MLP model based on the root mean

M. A. Mohandes; T. O. Halawani; S. Rehman; Ahmed A. Hussain

2004-01-01

9

Development of controller strategies for a robotized filament winding equipment  

NASA Astrophysics Data System (ADS)

The composites reinforced with continuous fibers of polymeric material are increasingly used in applications where it is essential to reduce weight, mainly due to their high ratio of strength/weight and rigidity/weight. A conventional application are pressure vessels, used for storing liquids or gases subjected to low or high pressure, where the tape continuous fiber-reinforced polymeric matrix material is wound around a mandrel defining the final geometry. In this context the filament winding process is a very attractive process for the production of composite components. For optimal structural performance, and greater weight saving, an optimal path should be adopted, resulting only in axial tension in the longitudinal direction (slip). Such path is the geodesic winding and diverse equipment may be used to guarantee the process automation of the winding. This work herein presented is focused on the study and development of the controller program for a robotized filament winding equipment, taking into account customization of possible trajectories controlling filament winding. The automation of the custom path according to user needs increases exponentially the capabilities, where the use of a robotized solution increases process flexibility and repeatability.

Lobo, Edgar; Machado, José; Mendonça, Joa~o. P.

2013-10-01

10

Heat flow analysis in connection with thermoplastic filament winding  

NASA Astrophysics Data System (ADS)

In thermoplastic filament winding the calculated rate of cooling is found to be in the order of 100000 degr.C/second at the bonding interface. Short range heat flow phenomena are analyzed, and the result provides a simple rule of thumb for practice, together with a winding speed dependant correction for glass and carbon fiber composites. This enables an easy method to calculate the lower temperature limits for the process of continuous welding, as well as the upper temperature limit where resin starved laminates result from excessive resin flow due to heat buildup. The applied model of heat transfer is given in analytical expressions. Calculated results are given in several graphs.

Brage, Anders; Lamrell, Charles

1988-04-01

11

Machine and Converter Reliabilities in Wind Turbines  

Microsoft Academic Search

Electrical Machine\\/Converter combinations are used in a variety of applications, from powers of Watts to MegaWatts. Some applications, such as propulsion and generation, have high reliability & availability requirements. Modern large wind turbines incorporate variable pitch blades and a variable speed Generator, which feeds the Grid through a Converter and have a need for high reliability & availability. There are

P J Tavner; G J W van Bussel; F Spinato

12

Counterbalance wheel for a wind machine  

Microsoft Academic Search

This patent describes a counterbalancing means for a wind machine configured with a driving reciprocating shaft and its prepelled reciprocatory load. This counter balancing modality consists of a number of interactive elements. The first components of the modality detailed in the patent are closely associated and consist of a frame and an axle journaled in a transverse direction to the

Sell

1986-01-01

13

Architecture-independent parallelism for both shared- and distributed-memory machines using the Filaments package  

Microsoft Academic Search

This paper presents the Filaments package, which can be used to create architecture-independentparallel programs---that is, programs that are portable and efficient across vastlydifferent parallel machines. Filaments virtualizes the underlying machine in terms of the numberof processors and the interconnection. This simplifies parallel program design in two ways.First, programs can be written (or generated) with the focus on the parallelism inherent

David K. Lowenthal; Vincent W. Freeh

2000-01-01

14

Multi-winding homopolar electric machine  

SciTech Connect

A multi-winding homopolar electric machine and method for converting between mechanical energy and electrical energy. The electric machine includes a shaft defining an axis of rotation, first and second magnets, a shielding portion, and a conductor. First and second magnets are coaxial with the shaft and include a charged pole surface and an oppositely charged pole surface, the charged pole surfaces facing one another to form a repulsive field therebetween. The shield portion extends between the magnets to confine at least a portion of the repulsive field to between the first and second magnets. The conductor extends between first and second end contacts and is toroidally coiled about the first and second magnets and the shield portion to develop a voltage across the first and second end contacts in response to rotation of the electric machine about the axis of rotation.

Van Neste, Charles W

2012-10-16

15

Zoning for wind machines: A guide for Minnesota communities  

NASA Astrophysics Data System (ADS)

Information on wind machines and related zoning issues is provided enable planning and zoning staff and elected officials to make informed decisions on small wind machines will be addressed in community plans and zoning. Background information on wind machines is provided. Model zoning language with full discussions explaining the model provisions comprise the bulk of the guide. Zoning concerns addressed include definitions, use designation, size regulations, safety of installation and design, siting regulations, noise, and communications interference. Model planning goals and policies on use designation and wind access are provided. Model subdivisions regulations on facilitating siting of wind machines in areas of new development are also included.

1983-08-01

16

Winding factors and Joule losses of permanent magnet machines with concentrated windings  

Microsoft Academic Search

The torque to MMF ratio of a permanent magnet machine with concentrated windings is normally much lower than for the more traditionally used distributed windings. BLDC and AC machines with concentrated windings usually have a slot pitch of only 2\\/3 the length of the pole pitch, which results in a poor fundamental winding factor of 0,866. This can be compared

Freddy Magnussen; Chandur Sadarangani

2003-01-01

17

Effects of wind speed variations and machine inertia constants on variable speed wind turbine dynamics  

Microsoft Academic Search

With the increasing wind power penetration, the wind farms are directly influencing the power systems. Therefore, analysis of wind power dynamics has become a very important issue, which justifies the need of a detailed dynamic model of wind power generation system. This paper approaches towards the study on the effect of wind speed variations and machine inertia constants on transient

M. A. Chowdhury; N. Hosseinzadeh; W. Shen

2010-01-01

18

Development of Induction Machines in Wind Power Technology  

Microsoft Academic Search

This paper gives an overview of the development of the induction machine as a generator for wind turbines from the middle of the 20th century up to now. After a short history chapter the different energy conversion concepts are presented. At first a squirrel cage machine is direct coupled to the grid (Danish concept). To adjust the machine speed the

Stefan Soter; R. Wegener

2007-01-01

19

Filament to mandrel gap analysis: Resulting gap from filament winding over a cone-cylinder transition mandrel (reference NMTP NO. 93838)  

SciTech Connect

The composites industry employs a method of high speed continuous reinforcement lay-down called filament winding. This is a process where resin impregnated tows, bundles of filament, are wound over a rotating mandrel. The tows, hereafter referred to as filament, are laid down over the rotating mandrel at a prescribed wind angle. Consider a cylindrical filament winding mandrel with conical features such that the filament is tangent to both the cylinder and the cone simultaneously. A gap is formed between the points of tangency. The gap distance measured along a line normal to the filament and intersecting the mandrel`s axis of rotation. The maximum distance occurs between the filament and a point on the intersection of the cylinder and the cone. The problems this paper addresses are: given a cylindrical filament winding mandrel with conical features, what is the gap size for a given wind angle; conversely what is the wind angle for a given gap size; and what does the geometry need to be in the mandrel transition area between the cylinder cone such that the filament remains in contact with the mandrel at all times?

Geraghty, P.

1993-10-27

20

Fields of Opportunity: Wind Machines Return to the Plains  

ERIC Educational Resources Information Center

|The last two decades have seen a rebirth of wind machines on the rural landscape. In ironic fashion the wind's kinetic energy has grown in significance through its ability to generate commercial amounts of electricity, the commodity that a few generations earlier hastened the demise of the old Great Plains windmill. Yet the reemergence of wind

Sowers, Jacob

2006-01-01

21

Prediction of transient behaviour of electrical machine windings  

Microsoft Academic Search

For economic design of stator winding insulation, a knowledge of voltage distribution within the winding, when the machine is subjected to fast fronted switching surges, is required. The proposed model, based on the traveling-wave approach, is capable of predicting surge voltages at any point in the winding with a reasonable degree of accuracy. The analysis is carried out for a

H. Oraee

1991-01-01

22

Analysis of filament wound composite structures considering the change of winding angles through the thickness direction  

Microsoft Academic Search

In this study, filament winding patterns were calculated using a semi-geodesic fiber path equation for an arbitrary surface. Because the fiber path depends on the surface where fibers are wound, the winding angle varies in the longitudinal and thickness directions of a wound structure. The fiber angle difference through the thickness was calculated for several design parameters, such as helical

Jae-Sung Park; Chang-Sun Hong; Chun-Gon Kim; Cheol-Ung Kim

2002-01-01

23

Counterbalance wheel for a wind machine  

SciTech Connect

This patent describes a counterbalancing means for a wind machine configured with a driving reciprocating shaft and its prepelled reciprocatory load. This counter balancing modality consists of a number of interactive elements. The first components of the modality detailed in the patent are closely associated and consist of a frame and an axle journaled in a transverse direction to the reciprocating shaft and contained within the frame. A principal feature of the counterbalance wheel mechanism which is characterized in the patent is a coupling means between the shaft and the load. The coupling means is depicted as being configured with a structure composed of an inner and outer portion with a rotary bearing means between them. The inner portion is indicated as having an opening which is eccentrically arranged within it for receiving the axle. Relatedly, the patent describes a means for pivotably mounting the outer portion of the coupling means to the driving shaft and to the load at opposite positions on the outer portion of the coupling means. The final interactive components described in order to totally depict the patent device are, first, a wheel carried by the axle and having a hub located in a lateral direction in comparison to the coupling means, and then an associated means for securing the wheel hub to the inner portion of the coupling means, as well as, a modality which exists on the wheel for counterbalancing the reciprocating shaft and load.

Sell, O.

1986-01-21

24

Filamentous \\  

Microsoft Academic Search

Hydrogen sulfide-rich groundwater discharges from springs into Lower Kane Cave, Wyoming, where mi- crobial mats dominated by filamentous morphotypes are found. The full-cycle rRNA approach, including 16S rRNA gene retrieval and fluorescence in situ hybridization (FISH), was used to identify these filaments. The majority of the obtained 16S rRNA gene clones from the mats were affiliated with the \\

Annette Summers Engel; Natuschka Lee; Megan L. Porter; Libby A. Stern; Philip C. Bennett; Michael Wagner

2003-01-01

25

Rotating Electric Machine Having a Toroidal Wound Motor Winding.  

National Technical Information Service (NTIS)

A rotor rotating electric machine having a toroidal winding assembly wound in a toroidal helix configuration. The toroidal winding includes four coils, each of which is wound in the form of a toroidal helix around a thin cylindrical ring. A rotor, coaxial...

K. H. Gutz

1981-01-01

26

Is titin a 'winding filament'? A new twist on muscle contraction  

PubMed Central

Recent studies have demonstrated a role for the elastic protein titin in active muscle, but the mechanisms by which titin plays this role remain to be elucidated. In active muscle, Ca2+-binding has been shown to increase titin stiffness, but the observed increase is too small to explain the increased stiffness of parallel elastic elements upon muscle activation. We propose a ‘winding filament’ mechanism for titin's role in active muscle. First, we hypothesize that Ca2+-dependent binding of titin's N2A region to thin filaments increases titin stiffness by preventing low-force straightening of proximal immunoglobulin domains that occurs during passive stretch. This mechanism explains the difference in length dependence of force between skeletal myofibrils and cardiac myocytes. Second, we hypothesize that cross-bridges serve not only as motors that pull thin filaments towards the M-line, but also as rotors that wind titin on the thin filaments, storing elastic potential energy in PEVK during force development and active stretch. Energy stored during force development can be recovered during active shortening. The winding filament hypothesis accounts for force enhancement during stretch and force depression during shortening, and provides testable predictions that will encourage new directions for research on mechanisms of muscle contraction.

Nishikawa, Kiisa C.; Monroy, Jenna A.; Uyeno, Theodore E.; Yeo, Sang Hoon; Pai, Dinesh K.; Lindstedt, Stan L.

2012-01-01

27

WindTech TV: Bonus Materials- Machine Control Circuits  

NSDL National Science Digital Library

This section of the Wind Technician TV website provides bonus materials pertaining to machine control circuits. Users can review content on topics like electrical theory, magnetics, ladder diagrams and start-stop interlock example. Clicking on a subtopic will launch a pop up window demonstrating the concept.

2013-07-01

28

Construction of helical coil winding machine for LHD and on-site winding  

Microsoft Academic Search

On-site winding of two helical coils of LHD started at the beginning of 1995, using a numerically controlled winding machine. They are large-scale pool-cooled superconducting coils which are designed to satisfy fully stabilized criterion. The conductor consists of Nb-Ti\\/Cu strands with a pure aluminum stabilizer and copper sheath. The main demanded values for winding the coils are 2.0 mm and

S. Imagawa; N. Yanagi; S. Yamaguchi; T. Satow; J. Yamamoto; O. Motojima; T. Senba; S. Suzuki; K. Nakanishi; K. Asano; T. Yamagiwa

1996-01-01

29

A new energy recovery double winding cage-rotor induction machine  

Microsoft Academic Search

This paper proposes a new double winding induction machine and its speed control methods. The machine consists of two stator windings and one cage rotor. One stator acts as a motor and the other as a generator. By controlling the voltage supplied to the secondary or the generator winding, the rotor speed can be adjusted. The machine has a similar

Lili Bu; Chun Li; Jeff Krukowski; Wilsun Xu; Xian Liu

2003-01-01

30

The Inertial Response of Induction-Machine-Based Wind Turbines  

Microsoft Academic Search

The inertial response of a generator is influenced by the sensitivity of the generator's electromagnetic torque to changes in the power system frequency. This paper deals with the inertial response of wind turbines employing induction-machine-based generators. A model of a field-oriented controlled doubly fed induction generator based on a fifth-order induction-generator model is described. The proposed model is implemented in

Alan Mullane; Mark O'Malley

2005-01-01

31

Air-gap flux density optimization in dual stator winding induction machines  

Microsoft Academic Search

The vector control of the dual stator winding induction machine is investigated in this paper. A simplified model for the dual stator winding induction machine considering it as two different induction machines coupled by the rotor can be used to study different control algorithms. The validity of the model will be proven. This model can only be considered if the

Juan M. Guerrero; Olorunfemi Ojo

2008-01-01

32

Fault tolerant switched reluctance machine for wind turbine blade pitch control  

Microsoft Academic Search

The paper's goal is to accomplish a study regarding the usefulness of a fault tolerant machine in wind turbine pitch control. The pitch control both helps to catch the wind at the optimal angle of attack of the blade's airfoil and to turn the blades out of the wind when maximum speed is exceeded. To fulfill this assignment electrical machines

Mircea RUBA; Loránd SZABÓ; Florin JURCA

2009-01-01

33

Terrain and Ambient Wind Effects on the Warming Footprint of a Wind Machine  

SciTech Connect

An experiment in a vineyard in south-central Washington is described in which a vineyard wind machine used for frost protection was turned on and off while monitoring the air temperature in the vineyard. The wind machine fan, with a hub height of 12 m, rotated around a quasi-horizontal axis that was tilted downward into the vineyard at an angle of 6 degrees. The fan also rotated around a vertical axis once every 4 minutes to protect a roughly circular area surrounding the wind machine tower. A temperature inversion of about 3.5 C occurred above the vineyard between the 3-m and hub-height levels during the experiments. The 300-m diameter warming footprint of the fan was displaced down the south-facing 1-2{sup o} slope of the vineyard when the ambient wind speed was low, showing the effect of the weak and shallow nighttime drainage flow that often occurred in the vineyard. When the ambient wind speed increased, the footprint was displaced downwind and downslope of the tower. The mean warming footprint magnitude when the fan was switched on was about 1-2 C, and the temperature excess in the footprint relative to the surroundings dissipated quickly when the fan was switched off.

Mcmeeking, Gavin R.; Whiteman, Charles D.; Powell, Stuart G.; Clements, Craig B.

2002-05-20

34

Fabrication of low cost composite tooling for filament winding large structures  

NASA Astrophysics Data System (ADS)

A TQM/concurrent engineering approach has been used to create a low cost filament-winding mandrel for large launch-vehicle structure fabrication. The process involves the fabrication of a low cost/low temperature master model, followed by the building of the mandrel and its backup structure within the master. Mandrels fabricated by these means are able to maintain full vacuum integrity and dimensional stability throughout high-temperature cure cycles; the reduced thermal mass of the mandrel results in part-cure cycles that are shorter than those associated with conventional mandrel materials.

Miller, Timothy S.; Fortin, Christopher J.

35

Wet-filament winding fabrication of thick carbon fiber/polycyanate resin composite  

SciTech Connect

Polycyanate resins offer advantages as composite matrices because of their high thermal stability, low outgassing, low water absorption and radiation resistance. This report describes the fabrication of a thick (nominal 1 in.) hoop-wound composite cylinder that is manufactured by the wet-filament winding method using Toray T1000G carbon fiber and YLA RS-14 polycyanate resin as the constituent materials. An analytical model used to evaluate the fabrication process, estimate composite residual stresses and provide input toward mandrel design is presented and the construction of the mandrel used to wet-wind the cylinder is described. The composite cylinder quality is evaluated by dimensional inspection and measurements of density and composition.

Frame, B.J.; Dodge, W.G.

1997-06-01

36

A model of the winding and curing processes for filament-wound composites  

SciTech Connect

A two-dimensional model that describes the winding and curing processes of filament-wound composite structures was developed in two parts. The first part is the cure model which relates the cure temperature, applied at the boundaries of the composite, to the thermal, chemical, and physical processes occurring in the case during cure. For a specified cure cycle, the cure model can be used to calculate the temperature distribution, the degree of cure of the resin, and the resin viscosity inside the composite case. The second part is the layer-tension loss and compaction model which relates the winding-process variables (i.e., winding pattern, mandrel geometry, initial winding tension, and the properties of the fiber and resin system) to the instantaneous position and tension of the fibers in each layer of the case. Verification of the cure submodel was accomplished by measuring the temperature distributions in a 5.75-inch-diameter graphite - epoxy test bottle and a 4-inch-diameter graphite - epoxy tube during cure. A parametric study was performed by using the finite-element FWCURE computer code. Results illustrate the information that can be generated by the models and the importance of different processing and material parameters on the fabrication process.

Tzeng, J.T.S.

1988-01-01

37

Fuzzy logic control of variable speed induction machine wind generation system  

Microsoft Academic Search

This paper presents the use of fuzzy logic control (FLC) of a variable speed induction machine wind generation system. The generation system uses three fuzzy logic controllers (FLC's), first fuzzy logic controller tracks the generator speed with wind velocity to extract maximum power. Second fuzzy logic controller programs the machine flux for light load efficiency improvement. Third fuzzy logic controller

M. K. K. Reddy; G. Sreenivasulu

2010-01-01

38

Partial discharge measurements on the winding bars from a failed machine  

Microsoft Academic Search

Partial discharge (PD) measurement is an effective tool for the evaluation and monitoring of machine insulation condition. Assessment by PD measurement of the winding bars from a failed electric machine identified the cause of the failure and defined the condition of the insulation. The correlation of PD measurements on the machine prior to failure with the post-failure assessment shows where

Y. Zhou; A. Gardiner; G. Mathieson; Y. Qin

1997-01-01

39

Wind  

NSDL National Science Digital Library

This document examine wind power as an energy resource. The reading will define wind and discuss topics such as (1) The history of wind machines, (2) Today's windmills, and (3) Types of wind machines. This resource is structured as an informational handout to supplement your energy activities or to generate discussion questions. Copyright 2005 International Technology Education Association

National Energy Education Development (NEED) Project

2003-01-01

40

Multiple machine representation of DFIG based grid-connected wind farms for SSR studies  

Microsoft Academic Search

This work studies the Sub-Synchronous Resonance (SSR) interactions that can take place when a DFIG-based wind farm is connected to the electrical grid through a series-compensated transmission line. As opposed to recent literature on the subject, a multiple machine model is employed to represent the wind farm. This representation allows taking into account machine speed variability due to wind parks

S. Atayde; A. Chandra

2011-01-01

41

Winding Inductances of Fractional Slot Surface-Mounted Permanent Magnet Brushless Machines  

Microsoft Academic Search

Permanent magnet (PM) brushless machines equipped with fractional-slot concentrated-windings (FSCW) have been receiving considerable attention over the past few years, due to the fact that they have short end-windings, a high slot fill factor, a high efficiency and power density, and good flux- weakening and fault-tolerance capabilities. A key design parameter for such machines is the phase winding inductance since

Ayman M. EL-Refaie; Z. Q. Zhu; T. M. Jahns; D. Howe

2008-01-01

42

Winding inductances of fractional slot surface-mounted permanent magnet brushless machines  

Microsoft Academic Search

Purpose – Permanent magnet (PM) brushless machines equipped with fractional-slot concentrated-windings (FSCW) have been receiving considerable attention over the past few years, due to the fact that they have short end-windings, a high-slot fill factor, a high efficiency and power density, and good flux-weakening and fault-tolerance capabilities. A key design parameter for such machines is the phase winding inductance since

Ayman M. EL-Refaie; Z. Q. Zhu; Thomas M. Jahns; David Howe

2009-01-01

43

Pole-phase modulated toroidal winding for an induction machine  

DOEpatents

A stator (10) for an induction machine for a vehicle has a cylindrical core (12) with inner and outer slots (26, 28) extending longitudinally along the inner and outer peripheries between the end faces (22, 24). Each outer slot is associated with several adjacent inner slots. A plurality of toroidal coils (14) are wound about the core and laid in the inner and outer slots. Each coil occupies a single inner slot and is laid in the associated outer slot thereby minimizing the distance the coil extends from the end faces and minimizing the length of the induction machine. The toroidal coils are configured for an arbitrary pole phase modulation wherein the coils are configured with variable numbers of phases and poles for providing maximum torque for cranking and switchable to a another phase and pole configuration for alternator operation. An adaptor ring (36) circumferentially positioned about the stator improves mechanical strength, and provides a coolant channel manifold (34) for removing heat produced in stator windings during operation.

Miller, John Michael (Saline, MI); Ostovic, Vlado (Weinheim, DE)

1999-11-02

44

Use of support vector machine for wind speed prediction  

Microsoft Academic Search

The penetration of wind energy has been encouraged significantly throughout the world. The wind power is a clean, inexhaustible, and almost a free source of energy. But the integration of wind parks with the power grid has resulted in many challenges for the unity in terms of commitment and control of power plants. As wind speed and wind direction fluctuate

Patil SangitaB; Surekha. R. Deshmukh

2011-01-01

45

Internal Pressure Carrying Capacity for Different Loading Modes of Filament-Wound Pipes from Glass Fiber-reinforced Epoxy Composites  

Microsoft Academic Search

Development of a low-cost filament-winding machine is initially described in this paper. The filament-winding machine was used to fabricate composite pipes and the materials used were woven glass fiber and epoxy resin. The pipes were tested under three loading modes, namely mode I (hoop pressure loading), mode II (biaxial pressure loading), and mode III (biaxial pressure with axial compressive loading).

F. H. Abdalla; S. M. Sapuan; M. M. Hamdan; B. Sahari

2008-01-01

46

Reduced switch count double converter fed wound rotor induction machine drive for wind energy application  

Microsoft Academic Search

A reduced switch count double side converter fed wound rotor induction machine control for a wind energy application is proposed in this paper. The outputs of two converters are combined electromechanically in the machine and are capable of sharing the power equally both from stator and rotor simultaneously. In order to reduce the cost a new configuration using two half

D. Panda; T.A. Lipo

2003-01-01

47

Dynamic model for Brushless Doubly-Fed Machine with stator winding faults  

Microsoft Academic Search

In this paper, a detailed analytical model for dynamic analysis of the Brushless Doubly-Fed Machine is presented. The model is capable to predict the machine behavior under different modes of operation including: simple induction mode, cascade mode and synchronous mode, both with and without winding faults and unbalanced excitations. The proposed approach employs the basic principles of the generalized harmonic

Hamed Gorgin; Pedram Sotoodeh; Hashem Oraee

2010-01-01

48

Unbalanced magnetic forces in permanent magnet brushless machines with diametrically asymmetric phase windings  

Microsoft Academic Search

A general analytical model, formulated in 2-D polar coordinates, is developed to predict the unbalanced magnetic force which results in permanent magnet brushless AC and DC machines having a diametrically asymmetric disposition of slots and phase windings. It is shown that the unbalanced magnetic force can be significant in machines having a fractional ratio of slot number to pole number,

D. Ishak; Z. Q. Zhu; D. Howe

2005-01-01

49

Unbalanced Magnetic Forces in Permanent-Magnet Brushless Machines With Diametrically Asymmetric Phase Windings  

Microsoft Academic Search

A general analytical model, formulated in 2-D polar coordinates, is developed to predict the unbalanced magnetic force, which results in permanent-magnet brushless ac and dc machines having a diametrically asymmetric disposition of slots and phase windings. It is shown that the unbalanced magnetic force can be significant in machines having a fractional ratio of slot number to pole number, particularly

Z. Q. Zhu; Dahaman Ishak; David Howe; Chen Jintao

2007-01-01

50

Power smoothing in wind generation systems using a sensorless vector controlled induction Machine driving a flywheel  

Microsoft Academic Search

This paper presents a novel control strategy for power smoothing in generation systems in which power flow variations can occur. These variations are the norm in wind energy generation. The system is based on a sensorless vector controlled induction machine driving a flywheel. The induction machine is controlled to operate in a wide speed range by using flux weakening above

Roberto Cárdenas; Rubén Peña; Greg Asher; Jon Clare

2004-01-01

51

A filtering technique to solve flicker problems due to use of induction machines in wind power generation  

Microsoft Academic Search

Squirrel cage induction machines represent a common solution widely adopted in wind generation. In fact, the induction machine is simple, reliable, cheap and requires very little maintenance. The employment of induction machines in wind power generation system needs, however, particular care and braininess. It is well known, in fact, that generator operating conditions can imply saturation of magnetic circuits of

Diego Iannuzzi; Luigi Piegari; Renato Rizzo

2005-01-01

52

Dynamic stability of wind turbines with permanent magnet machines and power-electronic converters  

Microsoft Academic Search

This paper is concerned with the transient stability of variable-speed wind turbines with permanent magnet synchronous machines at a pitch control malfunction. As wind power generation undergoes rapid growth, new technical challenges emerge: dynamic stability and power quality. We study the influence of a pitch control malfunction on the quality of the energy injected into the electrical grid, analyzing the

R. Melicio; V. M. F. Mendes; J. P. S. Catalao

2009-01-01

53

The use of time domain spectroscopy as a diagnostic tool for rotating machine windings  

Microsoft Academic Search

In order to assess stator winding insulation condition, a field instrument measuring the charge and the discharge current flowing through rotating machine stator winding groundwall insulation was developed at Hydro-Quebec. This instrument applies a constant DC-voltage of 1 kV during a certain time, usually 2000 s. Immediately following the charging, the stator winding is short-circuited during another period of time.

Eric David; Laurent Lamarre; Duc Ngoc Nguyen

2002-01-01

54

Development of Special Winding Machine for HT-7U Superconducting Tokamak  

NASA Astrophysics Data System (ADS)

A special winding machine with high accuracy has just been developed and applied to the construction of HT-7U Tokamak. It is one of the critical facilities for R & D of HT-7U construction. The machine mainly consists of five parts, including a CICC pay-off spool, a four-roller correcting assembly, a four-roller forming/bending assembly, a continuous winding structure and a CNC control system with three-axis AC servo motors. The facility is used for Cable in Conduit Conductor (CICC) magnet fabrication of HT-7U. The main requirements of the winding machine are: continuous winding to reduce joints inside the coils; pre-forming CICC conductor to avoid winding with tension; suitable for all TF & PF coils of various coil shapes and within the dimension limit; improving the configuration tolerance and the special flatness of the CICC conductor. This paper emphasizes on the design and fabrication of the special winding machine for HT-7U. Some analyses and techniques in winding process for trial D-shape coil are also presented.

Gao, Da-ming; Yu, Jie; Zhu, Wen-hua; Wen, Jun; Pan, Yin-nian; Chen, Le-ping; Tao, Yu-ming; Wang, Hai-jing; He, Wei

2000-02-01

55

Technological and economical analysis of salient pole and permanent magnet synchronous machines designed for wind turbines  

NASA Astrophysics Data System (ADS)

Chinese export restrictions already reduced the planning reliability for investments in permanent magnet wind turbines. Today the production of permanent magnets consumes the largest proportion of rare earth elements, with 40% of the rare earth-based magnets used for generators and other electrical machines. The cost and availability of NdFeB magnets will likely determine the production rate of permanent magnet generators. The high volatility of rare earth metals makes it very difficult to quote a price. Prices may also vary from supplier to supplier to an extent of up to 50% for the same size, shape and quantity with a minor difference in quality.The paper presents the analysis and the comparison of salient pole with field winding and of peripheral winding synchronous electrical machines, presenting important advantages. A neodymium alloy magnet rotor structure has been considered and compared to the salient rotor case. The Salient Pole Synchronous Machine and the Permanent Magnet Synchronous Machine were designed so that the plate values remain constant. The Eddy current effect on the windings is taken into account during the design, and the efficiency, output power and the air-gap flux density obtained after the simulation were compared. The analysis results clearly indicate that Salient Pole Synchronous Machine designs would be attractive to wind power companies. Furthermore, the importance of the design of electrical machines and the determination of criteria are emphasized. This paper will be a helpful resource in terms of examination and comparison of the basic structure and magnetic features of the Salient Pole Synchronous Machine and Permanent Magnet Synchronous Machine. Furthermore, an economic analysis of the designed machines was conducted.

Gündo?du, Tayfun; Kömürgöz, Güven

2012-08-01

56

A novel method for modeling dynamic air-gap eccentricity in synchronous machines based on modified winding function theory  

Microsoft Academic Search

This paper presents the modeling of synchronous machines under eccentric rotors. The winding function theory accounting for all space harmonics and presented by earlier researchers has been modified to adopt a nonsymmetric air-gap for the calculation of machine winding inductances. The effect of dynamic air-gap eccentricity on the inductances of a salient-pole synchronous machine using the modified winding function approach

Nabil A. Al-Nuaim; Hamid A. Toliyat

1998-01-01

57

Regulation of small wind machines: a local perspective  

SciTech Connect

The most common wind turbine issues that communities are concerned about and therefore might address in an ordnance are identified. These issues include noise, safety, communications interference, aesthetics, wind access, and height restrictions. How communities have addressed these issues as well as their approaches for dealing with small wind turbines in general are examined. In particular, the Riverside County, California, an ordinance recently prepared is explained in detail.

Perkins-Smith, D. (Black Hawk Associates, Denver, CO); Odland, R.

1982-01-01

58

Magnetically Shielded Electrical Machine With Superconducting Filed Windings.  

National Technical Information Service (NTIS)

The patent describes a superconducting coil mounted within the rotor of a homopolar machine. The section of the rotor surrounding the superconducting coil is enlarged to accommodate the coil and a dewar type container. Magnetic flux from the solenoid exte...

T. J. Doyle

1972-01-01

59

Development status of rotating machines employing superconducting field windings  

Microsoft Academic Search

Superconducting rotating machines have looked promising since multifilamentary niobium-titanium (NbTi) superconductors became available in the mid-1960s. Both dc homopolar and ac synchronous machines were successfully tested from the 1970s to the 1990s. Three different 70-MW generators were recently demonstrated by the SuperGM project in Japan. However, economic considerations with respect to competitive cost combined with the requirement for liquid helium

SWARN S. KALSI; KONRAD WEEBER; H. Takesue; CLIVE LEWIS; HEINZ-WERNER NEUMUELLER; RICHARD D. BLAUGHER

2004-01-01

60

A new three-phase doubly salient permanent magnet machine for wind power generation  

Microsoft Academic Search

This paper presents a new three-phase 12\\/8-pole doubly salient permanent-magnet (DSPM) machine for application to wind power generation. The key is to design and analyze the proposed DSPM generator, namely, the design of a new machine structure to achieve high power density and high robustness and the device of system operation to attain high efficiency. By using finite element analysis,

Ying Fan; K. T. Chau; Ming Cheng

2006-01-01

61

Analysis of a synchronous reluctance machine with an auxiliary single-phase winding  

Microsoft Academic Search

A three-phase synchronous reluctance machine having an axially laminated rotor structure and an auxiliary DC-source-fed single-phase control winding has utility as either a high-speed generator or a high-torque low-speed motor. This paper provides an understanding of its operation using electric circuit and electromagnetic field concepts in the process of which some insights are provided into the design of the windings,

Olorunfemi Ojo; Gan Dong; Mike Osaretin Omoigui

2003-01-01

62

Fractional-Slot Concentrated-Windings Synchronous Permanent Magnet Machines: Opportunities and Challenges  

Microsoft Academic Search

Fractional-slot concentrated-winding (FSCW) synchronous permanent magnet (PM) machines have been gaining interest over the last few years. This is mainly due to the several advantages that this type of windings provides. These include high-power density, high efficiency, short end turns, high slot fill factor particularly when coupled with segmented stator structures, low cogging torque, flux-weakening capability, and fault tolerance. This

Ayman M. EL-Refaie

2010-01-01

63

Investigation on Pole-Slot Combinations for Permanent-Magnet Machines with Concentrated Windings  

Microsoft Academic Search

The aim of this paper is to find the best concentrated windings layouts for high pole number permanent-magnet (PM) machines. Pole and slot numbers are varied from 4 to 80 and 6 to 90 respectively. Among all the pole\\/slot combinations, those giving the highest winding factors are provided. Harmonics in the magneto-motive force (MMF), torque ripple and radial magnetic forces

F. Libert; J. Soulard

64

Growing Neural Gas (GNG)Based Maximum Power Point Tracking for High-Performance Wind Generator With an Induction Machine  

Microsoft Academic Search

This paper presents a maximum power point track- ing (MPPT) technique for a high-performance wind generator with induction machine based on the growing neural gas (GNG) network. Here, a GNG network has been trained offline to learn the turbine characteristic surface torque versus wind speed and machine speed. It has been implemented online to perform the inversion of this function,

Maurizio Cirrincione; Marcello Pucci; Gianpaolo Vitale

2011-01-01

65

A Basic Study of Wind Generator Stabilization with Doubly-Fed Asynchronous Machine  

NASA Astrophysics Data System (ADS)

This paper investigates the function of DASM (Doubly-fed ASynchronous Machine) with emphasis placed on its ability to the stabilization of the power system including wind generators. P (active power) and Q (reactive power) compensation from DASM can be regulated independently through secondary-excitation controlling. Simulation results by PSCAD show that DASM can restore the wind-generator system to a normal operating condition rapidly even following severe transmission-line failures. Comparison studies have also been performed between wind turbine pitch control and proposed method.

Wu, Li; Takahashi, Rion; Nakagawa, Masaki; Murata, Toshiaki; Tamura, Junji

66

A Mars 1 Watt vortex wind energy machine  

NASA Astrophysics Data System (ADS)

A Martian wind power generator capable of surviving impact and fulfilling the long-term (2-5 yr) low-level power requirements (1-2 W) of an unmanned surface probe is presented. Attention is given to a tornado vortex generator that was chosen on the basis of its capability to theoretically augment the available power that may be extracted for average Martian wind speeds of about 7.5 m/s. The generator offers comparable mass-to-power ratios with solar power sources.

Ralston, Michael; Crowley, Christopher; Thomson, Ronald; Gwynne, Owen

67

A Transverse Flux Permanent Magnet machine for micro-wind generation application  

Microsoft Academic Search

A new Transverse Flux Permanent Magnet (TFPM) generator topology is proposed for direct-drive wind turbine application. The peculiarity of TFPM machines is their high torque density, and attention is mainly focused on their configuration at concentrated flux. The main objective is to find an innovative structure for simplification of the constructive process with consequently reduced production costs. Many magnetic circuit

M. Bellucci; V. Isastia Cimino; R. Rizzo

2011-01-01

68

Basic concepts, status, opportunities, and challenges of electrical machines utilizing high-temperature superconducting (HTS) windings  

Microsoft Academic Search

An overview of the different approaches towards achieving a marketable application of a superconducting electrical machine, either as synchronous motor or generator, will be given. This field ranges from relatively small industrial drives to utility generators with large power ratings, from the low speed and high torque of wind power generators and ship propulsion motors, to high speed generators attached

J Frauenhofer; J Grundmann; G Klaus; W Nick

2008-01-01

69

Doubly Fed Induction Machine Control For Wind Energy Conversion System.  

National Technical Information Service (NTIS)

Due to increasing concerns about CO2 emissions and the shortage of fossil fuels, renewable energy has become a major topic in economic discussions. One renewable source is energy that can be extracted from the wind. This thesis covers the basics of using ...

J. G. Massey

2009-01-01

70

Field study of the aesthetics of small wind machines: a preliminary report  

SciTech Connect

A field study was conducted at the Rocky Flats Small Wind Systems Test Center to determine if aesthetic preferences exist for particular designs of small wind machines, and to gather data on the importance of aesthetics relative to other wind system issues. Participants on public tours of the Test Center were asked to answer several general questions and to rate the visual appearance of various working parts (rotor and nacelle), towers, and complete machines. Working parts included vertical- and horizontal-axis designs (both upwind and downwind), while towers included wood, concrete and steel columns, and various truss designs. In spite of a relatively small sample size (N = 139), the results indicate definite preferences for particular designs, with downwind horizontal-axis working parts and columnar towers receiving the highest ratings.

Strojan, C. L.; Lawrence, K.; O'Donnell, D.

1980-03-01

71

An adaptive Kalman filtering approach to induction machine stator winding temperature estimation based on a hybrid thermal model  

Microsoft Academic Search

The stator winding temperature of an induction machine is estimated from either a thermal model-based or an induction machine parameter-based temperature estimator. The thermal model-based temperature estimator is simple and robust, but it is usually incapable of giving an accurate temperature estimate tailored to a specific motor's thermal capacity. The induction machine parameter-based temperature estimator is accurate and machine-dependent, but

Zhi Gao; Thomas G. Habetler; Ronald G. Harley; Roy S. Colby

2005-01-01

72

Basic concepts, status, opportunities, and challenges of electrical machines utilizing high-temperature superconducting (HTS) windings  

NASA Astrophysics Data System (ADS)

An overview of the different approaches towards achieving a marketable application of a superconducting electrical machine, either as synchronous motor or generator, will be given. This field ranges from relatively small industrial drives to utility generators with large power ratings, from the low speed and high torque of wind power generators and ship propulsion motors, to high speed generators attached to turbines. Essentially HTS machine technology offers several advantages such as compactness (weight and volume reduction), increased efficiency, and other operational benefits. The machine features have to be optimized with regard to the specific application, and different concepts were developed by internationally competing teams, with Siemens being one of them. The achieved status in these fields will be summarized, pointing to the specific technical challenges to overcome. For this purpose we have not only to consider the technology of manufacturing the HTS rotor winding itself, but also to check requirements and availability of supporting technologies. This ranges from new challenges posed to the non-superconducting ("conventional") components of such innovative HTS machines, manufacturing superconducting material in the coming transition from 1st to 2nd generation HTS tape, cryogenic technology including material behavior, to new and challenging tasks in simulating and predicting the performance of such machines by computational tools. The question of market opportunities for this technology obviously is a function of all these aspects; however, a strong tendency for the near future is seen in the area of high-torque ship propulsion.

Frauenhofer, J.; Grundmann, J.; Klaus, G.; Nick, W.

2008-02-01

73

Directly driven rare-earth permanent-magnet electrical-machine prototype for wind energy applications  

Microsoft Academic Search

This paper presents finite element design and analysis of two radial-flux high-energy rare-earth permanent magnet electrical machines with new topology. It allows for short endwindings, which contributes to higher efficiency, higher power to weight ratio and low active material cost. Locating the windings in flat slots has further reduced the cost of active material. The permanent magnets are sintered NdFeB

M. S. Widyan; R. E. Hanitsch

2007-01-01

74

Design Considerations of a Direct Drive Brushless Machine With Concentrated Windings  

Microsoft Academic Search

This paper discusses the performance attributes of the open-slot, modular-wound, external-rotor, topology of electrical machine. Combinations of pole and slot numbers are presented for which the winding factor is maximal and torque ripple is minimal. An optimization of the magnetic circuit design of six promising pole-slot configurations is undertaken using a parametric finite element model (FEM) combined with a genetic

Rafal Wrobel; Phil H. Mellor

2008-01-01

75

Numerical simulation of kinetic Alfven waves to study filament formation and their nonlinear dynamics in solar wind and corona  

SciTech Connect

This paper presents a numerical simulation leading to the formation of intense magnetic filaments of kinetic Alfven waves (KAWs) in steady state when the nonlinearity arises due to ponderomotive effects and Joule heating. The nonlinear dynamical equation for the KAW satisfies the modified nonlinear Schroedinger equation. When the plain KAW is perturbed by a transverse perturbation, filamentary structures in solar wind and coronal holes are observed. By changing the parameters of the perturbation (such as the wave number and the phase factor), filamentary structures of KAW magnetic field have been observed. The effect of the change of the dimensionless transverse wave number {gamma} (normalized in terms of electron's collisionless skin depth of the KAW) plays a very important role on filamentary dynamics. Besides the study of the magnetic-field intensity, we have done various diagnostics such as phase portraits and surface plots, and also studied the power spectrum. The effect of changing the value of {gamma} on power spectrum is significant. The motion is found to be quasiperiodic and appears to be chaotic for different parametric regimes. The relevance of these studies in coronal heating and solar wind acceleration/turbulence has also been pointed out.

Singh, H.D.; Sharma, R.P. [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi-110016 (India)

2006-01-15

76

Analysis of a single-phase induction machine with a shifted auxiliary winding  

SciTech Connect

This paper extends the method of multiple reference frames to the analysis of asymmetrical induction motors with non-orthogonal stator windings, with particular emphasis on the permanent split capacitor (PSC) machine. The predictions of the method are verified by comparison to both experimental results and to results obtained using a machine variable computer simulation. Once verified, the method is used to derive the transfer function relating rotor speed to load torque disturbance, which is of particular interest when analyzing PSC machines driving compressor loads. It is shown that the transfer function exhibits a distinct resonant point, and that the magnitude of the resonant peak increases as the motor approaches synchronous speed. It is also shown that the magnitude of the resonant peak may be lowered by increasing rotational inertia or rotor resistance.

Walls, T.A. [Emerson Motor Co., St. Louis, MO (United States). Specialty Motor Div.; Sudhoff, S.D. [Univ. of Missouri, Rolla, MO (United States). Dept. of Electrical Engineering

1996-12-01

77

Development of a 2-kilowatt high-reliability wind machine. Phase I. Design and analysis. Volume I. Executive summary  

Microsoft Academic Search

A high reliability wind machine rated for 2 kW at 9 m\\/s has been designed to be cost-effective for remote site use. To meet or exceed environmental conditions as specified in Contract PF64410F, the resulting design defines a rugged, relatively simple wind machine. Rigorous fatigue analysis for structural components and development of redundant systems for electrical components led to an

W. Drake; H. Clews; J. Cordes; B. Johnson; P. Murphy

1980-01-01

78

Development of a 2-kilowatt high-reliability wind machine. Phase I. Design and analysis. Volume II. Technical report  

Microsoft Academic Search

A high reliability wind machine rated for 2 kW at 9 m\\/s has been designed to be cost-effective for remote site use. To meet or exceed environmental conditions as specified in Contract PF64410F, the resulting design defines a rugged, relatively simple wind machine. Rigorous fatigue analysis for structural components and development of redundant systems for electrical components led to an

W. Drake; H. Clews; J. Cordes; B. Johnson; P. Murphy

1980-01-01

79

Fault diagnosis of direct-drive wind turbine based on support vector machine  

NASA Astrophysics Data System (ADS)

A fault diagnosis method of direct-drive wind turbine based on support vector machine (SVM) and feature selection is presented. The time-domain feature parameters of main shaft vibration signal in the horizontal and vertical directions are considered in the method. Firstly, in laboratory scale five experiments of direct-drive wind turbine with normal condition, wind wheel mass imbalance fault, wind wheel aerodynamic imbalance fault, yaw fault and blade airfoil change fault are carried out. The features of five experiments are analyzed. Secondly, the sensitive time-domain feature parameters in the horizontal and vertical directions of vibration signal in the five conditions are selected and used as feature samples. By training, the mapping relation between feature parameters and fault types are established in SVM model. Finally, the performance of the proposed method is verified through experimental data. The results show that the proposed method is effective in identifying the fault of wind turbine. It has good classification ability and robustness to diagnose the fault of direct-drive wind turbine.

An, X. L.; Jiang, D. X.; Li, S. H.; Chen, J.

2011-07-01

80

Fuzzy logic based intelligent control of a variable speed cage machine wind generation system  

SciTech Connect

The paper describes a variable speed wind generation system where fuzzy logic principles are used for efficiency optimization and performance enhancement control. A squirrel cage induction generator feeds the power to a double-sided pulse width modulated converter system which pumps power to a utility grid or can supply to an autonomous system. The generation system has fuzzy logic control with vector control in the inner loops. A fuzzy controller tracks the generator speed with the wind velocity to extract the maximum power. A second fuzzy controller programs the machine flux for light load efficiency improvement, and a third fuzzy controller gives robust speed control against wind gust and turbine oscillatory torque. The complete control system has been developed, analyzed, and validated by simulation study. Performances have then been evaluated in detail.

Simoes, M.G. [Univ. of Sao Paulo (Brazil); Bose, B.K. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Electrical Engineering; Spiegel, R.J. [Environmental Protection Agency, Research Triangle Park, NC (United States), Air and Energy Engineering Research Lab.

1997-01-01

81

Direct-Matrix-Converter-Based Drive for a Three-Phase Open-End-Winding AC Machine With Advanced Features  

Microsoft Academic Search

This paper describes how matrix converters (MCs), one at each side of a three-phase open-end-winding ac machine, achieve the following features simultaneously: 1) machine phase voltage up to 1.5 times the input phase voltage in the linear modulation mode, therefore extending the rated torque operation region to 150% of the rated speed of the machine; 2) peak voltage stress across

Ranjan K. Gupta; Krushna K. Mohapatra; Apurva Somani; Ned Mohan

2010-01-01

82

Comparison Between Finite-Element Analysis and Winding Function Theory for Inductances and Torque Calculation of a Synchronous Reluctance Machine  

Microsoft Academic Search

This paper compares the prediction of two independent methods for calculating electromagnetic torque and inductances of a synchronous reluctance machine under linear condition. One method is based on winding function analysis (WFA) and the other on finite-element analysis (FEA). Both methods take into account the rotor geometry, the stator slot effects and the stator winding connections. The simulation results obtained

Thierry Lubin; Tahar Hamiti; Hubert Razik; Abderrezak Rezzoug

2007-01-01

83

Performance Analysis of an Induction Machine-Based Flywheel Energy Storage System Associated to a Variable-Speed Wind Generator  

Microsoft Academic Search

The flywheel energy storage systems (FESSs) are suitable for improving the quality of the electric power delivered by the wind generators and to help these generators to contribute to the ancillary services. This paper investigates the energetic performances of a low-speed FESS with a classical squirrel-cage Induction Machine (IM) in the aim of its association to a wind generator.

Gabriel CIMUCA; Mircea M. RADULESCU; Christophe SAUDEMONT; Benoît ROBYNS

84

Direct Torque Control for Doubly Fed Induction Machine-Based Wind Turbines Under Voltage Dips and Without Crowbar Protection  

Microsoft Academic Search

This letter proposes a rotor flux amplitude reference generation strategy for doubly fed induction machine based wind turbines. It is specially designed to address perturbations, such as voltage dips, keeping controlled the torque of the wind turbine, and considerably reducing the stator and rotor overcurrents during faults. In addition, a direct torque control strategy that provides fast dynamic response accompanies

G. Abad; M. A. Rodriguez; J. Poza; J. M. Canales

2010-01-01

85

Growing Neural Gas (GNG) based Maximum Power Point Tracking for high performance VOC-FOC based wind generator system with an induction machine  

Microsoft Academic Search

This paper presents a MPPT technique for high performance wind generator with induction machine based on the Growing Neural Gas (GNG) network. Here a GNG network has been trained off-line to learn the turbine characteristic surface torque versus wind speed and machine speed, and implemented on-line so to perform the inversion of this function obtaining the wind free speed on

Maurizio Cirrincione; Marcello Pucci; Gianpaolo Vitale

2009-01-01

86

A novel wind-power generating system using field orientation controlled doubly-excited brushless reluctance machine  

Microsoft Academic Search

A novel variable-speed constant-frequency wind power generating system using a doubly-excited brushless reluctance machine is proposed. A field orientation control method is proposed to track the optimal torque-speed profile of the wind turbine and to realize flexible reactive power control. The proposed wind power generating system has the potentials of high efficiency, good flexibility, and low cost

Longya Xu; Yifan Tang

1992-01-01

87

A novel design of DC-AC electrical machine rotary converter for hybrid solar and wind energy applications  

NASA Astrophysics Data System (ADS)

This paper proposes the design of a new bi-directional DC-AC rotary converter machine to convert a d.c. voltage to three-phase voltage and vice-versa using a two-stage energy conversion machine. The rotary converter consists of two main stages which are combined into single frame. These two stages are constructed from three main electromagnetic components. The first inner electromagnetic component represents the input stage that enables the DC power generated by solar energy from photo-voltaic cells to be transformed by the second and third components electro-magnetically to produce multi-phase voltages at the output stage. At the same time, extra kinetic energy from wind, which is sufficiently available, can be added to existing torque on the second electromagnetic component. Both of these input energies will add up to the final energy generated at the output terminals. Therefore, the machine will be able to convert solar and wind energies to the output terminals simultaneously. If the solar energy is low, the available wind energy will be able to provide energy to the output terminals and at the same time charges the batteries which are connected as backup system. At this moment, the machine behaves as wind turbine. The energy output from the machine benefits from two energy sources which are solar and wind. At night when the solar energy is not available and also the load is low, the wind energy is able to charge the batteries and at the same time provides output electrical power to the remaining the load. Therefore, the proposed system will have high usage of available renewable energy as compared to separated wind or solar systems. MATLAB codes are used to calculate the required dimensions, the magnetic and electrical circuits parameters to design of the new bi-directional rotary converter machine.

Mohammed, K. G.; Ramli, A. Q.; Amirulddin, U. A. U.

2013-06-01

88

Induction machine  

SciTech Connect

A polyphase rotary induction machine for use as a motor or generator utilizes, a single rotor assembly having two series connected sets of rotor windings, a first stator winding disposed around the first rotor winding and means for controlling the current induced in one set of the rotor windings compared to the current induced in the other set of the rotor windings. The rotor windings may be wound rotor windings or squirrel cage windings.

Owen, W.H.

1980-10-14

89

Induction machine  

DOEpatents

A polyphase rotary induction machine for use as a motor or generator utilizing a single rotor assembly having two series connected sets of rotor windings, a first stator winding disposed around the first rotor winding and means for controlling the current induced in one set of the rotor windings compared to the current induced in the other set of the rotor windings. The rotor windings may be wound rotor windings or squirrel cage windings.

Owen, Whitney H. (Ogden, UT)

1980-01-01

90

Filaments Programmer's Manual  

Microsoft Academic Search

This report describes how to write architecture-independent parallel programs---programs that are portable and efficient across vastly different parallel machines---using the Filaments package. All user-visible functions are described in detail, alongwith a description of how to convert two sample sequential programs to Filamentsprograms. All necessary details to install and run Filaments are also included, as wellas an overview of the implementation.

David K. Lowenthal; Vincent W. Freeh

91

Performance of Double Fed Induction Machine at Sub and Super Synchronous Speed in Wind Energy Conversion System  

Microsoft Academic Search

In this paper two modes of operating a wound rotor induction machine as a generator at sub-and super-synchronous speeds in wind energy conversion systems are investigated. In the first mode, known as double fed induction generator (DFIG), the rotor circuit is fed from the ac mains via a controlled rectifier and a forced commutated inverter. Adjusting the applied rotor voltage

Mona N. Eskander; Mahmoud A. Saleh; Mohsen M. T. El-Hagry

2009-01-01

92

Analytical determination of optimal split ratio for overlapping and non-overlapping winding external rotor PM brushless machines  

Microsoft Academic Search

The split ratio between the rotor and stator outer diameters is an important design parameter. Considerable research has been carried out for the analytical determination of the optimal split ratio in both internal rotor and tubular permanent magnet brushless machines over last decade. In this paper, the optimal split ratio for both non-overlapping and overlapping winding external rotor permanent magnet

Yang Shen; Z. Q. Zhu; L. J. Wu

2011-01-01

93

Modified vector control algorithm for increasing partial-load efficiency of fractional-slot concentrated-winding surface PM machines  

SciTech Connect

This paper presents a modified vector control algorithm for a fractional-slot concentrated-winding surface PM machine that has been developed to maximize the machine's partial-load efficiency over a wide range of operating conditions. By increasing the amplitude of the negative d-axis current, the resulting increase in the stator copper losses can be more than offset by the reduction in the iron core losses achieved by lowering the stator d-axis flux amplitude. The effectiveness of this technique has been demonstrated using both analytical models and finite element analysis (FEA) for a 55 kW (peak) surface PM machine design developed for a demanding set of traction drive performance requirements. For this example, the modified control strategy increases the partial-load efficiency at 20% of rated torque by >6% at 2000 rpm compared to the maximum torque/amp algorithm, making the machine much more attractive for its intended application

El-Refaie, Ayman M [ORNL; Jahns, Thomas M [ORNL; Reddy, Patel [University of Wisconsin; McKeever, John W [ORNL

2006-01-01

94

An experimental and numerical study of the vortex filaments in the wake of an operational, horizontal-axis, wind turbine  

Microsoft Academic Search

The paper describes a wind-tunnel study of the wake dynamics of an operational, horizontal-axis wind turbine. The behaviour of the vorticity trailing from the turbine blade tips and the effect of was interference on wake development were considered. Laser sheet visualisation (LSV) techniques were used to measure the trajectories of the trailing vorticity under various conditions of turbine yaw and

I. Grant; M. Mo; X. Pan; P. Parkin; J. Powell; H. Reinecke; K. Shuang; F. Coton; D. Lee

2000-01-01

95

Performance Comparison and Winding Fault Detection of Duplex 2Phase and 3Phase Fault-Tolerant Permanent Magnet Brushless Machines  

Microsoft Academic Search

This paper analyses feasible slot and pole number combinations for multiplex 2-phase and 3-phase fault-tolerant permanent-magnet machines and evaluates their relative merits via a design case study. An effective winding short-circuit detection technique based on search coils wound around the stator teeth is also presented, and its performance is assessed. It is shown that the proposed detection technique can reliably

Jie Chai; Jiabin Wang; Kais Atallah; David Howe

2007-01-01

96

Detection of inter-coil short circuits in the stator winding of a PM machine by using saliency tracking schemes  

Microsoft Academic Search

This paper demonstrates the feasibility of using saliency tracking schemes (normally associated with sensorless control of drives) for the detection of inter-coil short circuits in the stator windings of a PM machine. This is obtained through a co-simulating of Matlab\\/Simulink and a Finite Element Model (FEM). Vector control and sensorless control schemes based on saliency tracking were implemented using Simulink,

J. Arellano-Padilla; M. Sumner; C. Gerada; G. Buckley

2011-01-01

97

Fuzzy logic based intelligent control of a variable speed cage machine wind generation system. Report for January 1994-June 1995  

SciTech Connect

The paper describes a variable speed wind generation system where fuzzy logic principles are used for efficiency optimization and performance enhancement control. A squirrel cage induction generator feeds the power to a double-sided pulse width modulated converter system which pumps power to a utility grid or can supply to an autonomous system. The generation system has fuzzy logic control with vector control in the inner loops. A fuzzy controller tracks the generator speed with the wind velocity to extract the maximum power. A second fuzzy controller programs the machine flux for light load efficiency improvement, and third fuzzy controller gives robust speed control against wind gust and turbine oscillatory torque. The complete control system has been developed, analyzed, validated by simulation study, and then performances have been evaluated in detail.

Simoes, M.G.; Bose, B.K.; Spiegel, R.J.

1995-10-01

98

Three-dimensional analysis of inductances and magnetic fields in the air-cored armature windings of a superconducting synchronous machine  

SciTech Connect

Although the inductances of an iron-cored synchronous machine can be calculated precisely by established conventional methods, it is not easy to calculate the inductances and flux distribution of air-cored synchronous machines. The flux distribution is greatly affected by the structure of the winding and, therefore, it is very important to clarify the three-dimensional distribution of the magnetic field taking into acount the shape of the windings. Two types of air-cored armatures are presented. These are the diamond type and the helical type. The magnetic flux distribution, inductances, and other performances of the diamond-type winding are compared to the helical-type winding. The results from the analysis to derive calculation formulas for armature reaction flux and winding inductances are presented.

Mukai, E.; Muta, I.; Yagi, M.

1980-01-01

99

Design considerations for fractional-slot winding configurations of synchronous machines  

Microsoft Academic Search

This paper presents some design considerations for synchronous machines characterized by a fractional number of slots per pole per phase. The main advantage of this configuration is a smooth torque, which is due to the elimination of periodicity between slots and poles. A second advantage is a higher fault-tolerant capability, making the machine able to work even in faulty conditions.

Nicola Bianchi; Silverio Bolognani; Michele Dai Pré; Giorgio Grezzani

2006-01-01

100

An Efficient Wind–Photovoltaic Hybrid Generation System Using Doubly Excited Permanent-Magnet Brushless Machine  

Microsoft Academic Search

With ever-increasing concerns on energy issues, the development of renewable energy sources is becoming more and more attractive. This paper first reviews both the wind power and photovoltaic (PV) power generation techniques and their maximum-power-point tracking (MPPT) methods. Then, a new stand-alone wind-PV hybrid generation system is proposed for application to remote and isolated areas. For the wind power generation

Chunhua Liu; K. T. Chau; Xiaodong Zhang

2010-01-01

101

Transverse flux machines with distributed windings for in-wheel applications  

Microsoft Academic Search

Transverse flux machine (TFM) useful for in-wheel motor applications is presented. This transverse flux permanent magnet motor is designed to achieve high torque-to-weight ratio and is suitable for direct-drive wheel applications. As in conventional TFM, the phases are located under each other, which will increase the axial length of the machine. The idea of this design is to reduce the

Salwa Baserrah; Keno Rixen; Bernd Orlik

2009-01-01

102

Finite element analysis of Brushless Doubly-Fed Machine under stator winding faults  

Microsoft Academic Search

In this paper the finite element model of the Brushless Doubly-Fed Machine is presented. A magnetodynamic finite element model allowing the simulation of the healthy and faulted machine with its special rotor topology is extracted and simulated. To verify the validation of the proposed model the results are compared with couple circuit model, which used generalized harmonic theory. Keywords-Brushless Doubly-Fed

Hamed Gorginpour; Behzad Jandaghi; Hashem Oraee

2011-01-01

103

Actin Filaments  

Microsoft Academic Search

\\u000a Actin filaments form a dynamic skeletal and motility system in all eukaryotic cells. Interacting with the other main components\\u000a of the cytoskeleton, microtubules (cf. Fig. 72) and intermediate filaments (cf. Fig. 75), they are involved in all kinds of\\u000a cellular motion, including cell migration and division, changes of cell shapes during exocytosis and endocytosis, formation\\u000a of filopodia and lamellipodia during

Margit Pavelka; Jürgen Roth

104

Impact of Winding Layer Number and Slot\\/Pole Combination on AC Armature Losses of Synchronous Surface PM Machines Designed for Wide Constant-Power Speed Range Operation  

Microsoft Academic Search

This paper examines the impact of the winding layer number (single- and double-layer), and magnet type (sintered and bonded), as well as slot\\/pole combinations on AC stator losses in surface permanent magnet (SPM) synchronous machines equipped with fractional-slot concentrated windings that are designed for wide speed ranges of constant-power operation. It is shown that the use of bonded magnets instead

Patel B. Reddy; T. M. Jahns; Ayman M. El-Refaie

2008-01-01

105

Final Report on Control Algorithm to Improve the Partial-Load Efficiency of Surface PM Machines with Fractional-Slot Concentrated Windings  

SciTech Connect

Surface permanent magnet (SPM) synchronous machines using fractional-slot concentrated windings are being investigated as candidates for high-performance traction machines for automotive electric propulsion systems. It has been shown analytically and experimentally that such designs can achieve very wide constant-power speed ratios (CPSR) [1,2]. This work has shown that machines of this type are capable of achieving very low cogging torque amplitudes as well as significantly increasing the machine power density [3-5] compared to SPM machines using conventional distributed windings. High efficiency can be achieved in this class of SPM machine by making special efforts to suppress the eddy-current losses in the magnets [6-8], accompanied by efforts to minimize the iron losses in the rotor and stator cores. Considerable attention has traditionally been devoted to maximizing the full-load efficiency of traction machines at their rated operating points and along their maximum-power vs. speed envelopes for higher speeds [9,10]. For example, on-line control approaches have been presented for maximizing the full-load efficiency of PM synchronous machines, including the use of negative d-axis stator current to reduce the core losses [11,12]. However, another important performance specification for electric traction applications is the machine's efficiency at partial loads. Partial-load efficiency is particularly important if the target traction application requires long periods of cruising operation at light loads that are significantly lower than the maximum drive capabilities. While the design of the machine itself is clearly important, investigation has shown that this is a case where the choice of the control algorithm plays a critical role in determining the maximum partial-load efficiency that the machine actually achieves in the traction drive system. There is no evidence that this important topic has been addressed for this type of SPM machine by any other authors. This topic takes on even greater significance for fractional-slot concentrated-winding SPM machine designs. In particular, maximizing the torque/power density of this class of SPM machines typically leads to machine designs with high numbers of poles. The resulting high electrical frequencies can easily result in high stator core losses unless special care is taken during the machine design process. The purpose of this report is to discuss a modified vector control algorithm for a fractional-slot concentrated winding SPM machine that has been developed to maximize the machine's partial-load efficiency over a wide range of operating conditions. For purposes of this discussion, a 55 kW (peak) SPM machine designed to meet requirements established in the US FreedomCar program [13] is used as the basis for demonstrating the proposed technique. A combination of closed-form analysis [14] and finite element analysis (FEA) is used during this investigation.

McKeever, John W [ORNL; Reddy, Patel [University of Wisconsin; Jahns, Thomas M [ORNL

2007-05-01

106

FINAL REPORT ON CONTROL ALGORITHM TO IMPROVE THE PARTIAL-LOAD EFFICIENCY OFSURFACE PM MACHINES WITH FRACTIONAL-SLOT CONCENTRATED WINDINGS  

SciTech Connect

Surface permanent magnet (SPM) synchronous machines using fractional-slot concentrated windings are being investigated as candidates for high-performance traction machines for automotive electric propulsion systems. It has been shown analytically and experimentally that such designs can achieve very wide constant-power speed ratios (CPSR) [1,2]. This work has shown that machines of this type are capable of achieving very low cogging torque amplitudes as well as significantly increasing the machine power density [3-5] compared to SPM machines using conventional distributed windings. High efficiency can be achieved in this class of SPM machine by making special efforts to suppress the eddy-current losses in the magnets [6-8], accompanied by efforts to minimize the iron losses in the rotor and stator cores. Considerable attention has traditionally been devoted to maximizing the full-load efficiency of traction machines at their rated operating points and along their maximum-power vs. speed envelopes for higher speeds [9,10]. For example, on-line control approaches have been presented for maximizing the full-load efficiency of PM synchronous machines, including the use of negative d-axis stator current to reduce the core losses [11,12]. However, another important performance specification for electric traction applications is the machine's efficiency at partial loads. Partial-load efficiency is particularly important if the target traction application requires long periods of cruising operation at light loads that are significantly lower than the maximum drive capabilities. While the design of the machine itself is clearly important, investigation has shown that this is a case where the choice of the control algorithm plays a critical role in determining the maximum partial-load efficiency that the machine actually achieves in the traction drive system. There is no evidence that this important topic has been addressed for this type of SPM machine by any other authors. This topic takes on even greater significance for fractional-slot concentrated-winding SPM machine designs. In particular, maximizing the torque/power density of this class of SPM machines typically leads to machine designs with high numbers of poles. The resulting high electrical frequencies can easily result in high stator core losses unless special care is taken during the machine design process. The purpose of this report is to discuss a modified vector control algorithm for a fractional-slot concentrated winding SPM machine that has been developed to maximize the machine's partial-load efficiency over a wide range of operating conditions. For purposes of this discussion, a 55 kW (peak) SPM machine designed to meet requirements established in the US FreedomCar program [13] is used as the basis for demonstrating the proposed technique. A combination of closed-form analysis [14] and finite element analysis (FEA) is used during this investigation.

Reddy, P.B.; Jahns, T.M.

2007-04-30

107

Performance analysis of various configurations of Switched Reluctance Machine for wind energy applications  

Microsoft Academic Search

Climate change is a contemporary issue and the international communities have accepted the dangers of green house gas emissions. Renewable energy is one of the hot topics when it comes to dealing with green house gas emissions treatments. Wind generation is one of the renewable energy power sources that helps in reducing the carbon di oxide from our atmosphere and

E. Annie Elisabeth Jebaseeli; D. Susitra

2010-01-01

108

Power strategies for maximum control structure of a wind energy conversion system with a synchronous machine  

Microsoft Academic Search

The control of a wind energy conversion system can be decomposed into two parts: a local control depending on the power structure and a global control (strategy) deduced from global considerations. The local part ensures an efficient energy management of each component of the system. The local control structure can be deduced from the Energetic Macroscopic Representation, which is a

A. Bouscayrol; Ph. Delarue; X. Guillaud

2005-01-01

109

FUZZY LOGIC BASED INTELLIGENT CONTROL OF A VARIABLE SPEED CAGE MACHINE WIND GENERATION SYSTEM  

EPA Science Inventory

The report gives results of a demonstration of the successful application of fuzzy logic to enhance the performance and control of a variable-speed wind generation system. A squirrel cage induction generator feeds the power to either a double-sided pulse-width modulation converte...

110

FUZZY LOGIC BASED INTELLIGENT CONTROL OF A VARIABLE SPEED CAGE MACHINE WIND GENERATION SYSTEM  

EPA Science Inventory

The paper describes a variable-speed wind generation system where fuzzy logic principles are used to optimize efficiency and enhance performance control. A squirrel cage induction generator feeds the power to a double-sided pulse width modulated converter system which either pump...

111

Fuzzy Logic Based Intelligent Control of a Variable Speed Cage Machine Wind Generation System.  

National Technical Information Service (NTIS)

The report gives results of a demonstration of the successful application of fuzzy logic to enhance the performance and control of a variable-speed wind generation system. A squirrel cage induction generator feeds the power to a double-sided pulse-width m...

B. K. Bose M. G. Simoes

1997-01-01

112

A doubly-fed induction machine and energy storage system for wind power generation  

Microsoft Academic Search

Wind power has become a very important source of renewable energy, and has been shown to complement central generation effectively. However, good power quality from distributed generators is vital, and hence independent control of the real and reactive power is desirable. Also, there has been an increasing demand for alternative energy sources to behave like conventional generators, whereby their output

Chad Abbey; G. Joos

2004-01-01

113

An Online Adaptive Stator Winding Temperature Estimator Based on a Hybrid Thermal Model for Induction Machines  

Microsoft Academic Search

Conventional thermal models with a single thermal capacitor and a single thermal resistor are incapable of giving an accurate stator winding temperature estimate tailored to the specific motor's cooling capability. A hybrid thermal model is presented in this paper to account for the disparities in thermal operating conditions for different motors of the same rating, and of the same totally

Zhi Gao; Thomas G. Habetler; Ronald G. Harley

2005-01-01

114

Design considerations of a direct drive brushless PM machine with concentrated windings  

Microsoft Academic Search

The paper considers the optimal design of an open slot, external rotor torque motor. Combinations of pole and slot numbers are presented for which the winding factor is maximal and torque ripple is minimal. A detailed optimisation of the magnetic circuit design of the six most promising pole-slot configurations has been undertaken using the combination of a genetic algorithm (GA)

R. Wrobel; P. H. Mellor

2005-01-01

115

Fuzzy logic based intelligent control of a variable speed cage machine wind generation system  

Microsoft Academic Search

The paper describes a variable speed wind generation system where fuzzy logic principles are used for efficiency optimization and performance enhancement control. A squirrel cage induction generator feeds the power to a double-sided pulse width modulated converter system which pumps power to a utility grid or can supply to an autonomous system. The generation system has fuzzy logic control with

M. G. Simoes; B. K. Bose; R. J. Spiegel

1997-01-01

116

Feasibility Study of Filament Wound Cartridge Cases.  

National Technical Information Service (NTIS)

The feasibility of fabricating a 60mm composite cartridge case by the filament winding process has been demonstrated. Fabrication procedures for the manufacturing of this type of case are presented in this report. (Author)

G. D'Andrea R. Cullinan P. Croteau

1978-01-01

117

Isolation and characterization of filamentous bacteria from paper mill slimes  

Microsoft Academic Search

The composition of filamentous bacteria in paper machine systems has received little scientific scrutiny, even though these organisms have been associated with many problems that affect machine efficiency and paper quality. The objective of the study was to isolate and characterize filamentous bacteria in paper mill slimes using conventional microbiological techniques, fatty acid methyl ester (FAME) analysis, and 16S rRNA

David Oppong; Vanja M. King; Judith A. Bowen

2003-01-01

118

Beam distribution function after filamentation  

SciTech Connect

In this paper, the authors calculate the beam distribution function after filamentation (phase-mixing) of a focusing mismatch. This distribution is relevant when interpreting beam measurements and sources of emittance dilution in linear colliders. It is also important when considering methods of diluting the phase space density, which may be required for the machine protection system in future linear colliders, and it is important when studying effects of trapped ions which filament in the electron beam potential. Finally, the resulting distribution is compared with measured beam distributions from the SLAC linac.

Raubenheimer, T.O.; Decker, F.J.; Seeman, J.T.

1995-05-01

119

Characteristic analysis and comparison of axial flux machines according to magnetization pattern for 500 W-class wind power generator application  

NASA Astrophysics Data System (ADS)

This paper presents the electromagnetic characteristic analysis of axial flux machines applied to 500(W) class wind power generators. For the dramatic analysis time reduction, analytical method is applied, and comparative analysis is performed according to magnetization patterns of permanent magnets. Due to their structural features, quasi 3-dimensional analysis is employed, and correction function is introduced to consider the flux leakage of the machines. The analysis results are compared with the results by finite element method and experiment to validate the suggested method performed in this paper showing high reliability.

Park, Yu-Seop; Jang, Seok-Myeong; Ko, Kyoung-Jin; Choi, Jang-Young; Sung, So-Young

2012-04-01

120

Mars vertical axis wind machines. The design of a Darreus and a Giromill for use on Mars  

NASA Astrophysics Data System (ADS)

This report contains the design of both a Darrieus and a Giromill for use on Mars. The report has been organized so that the interested reader may read only about one machine without having to read the entire report. Where components for the two machines differ greatly, separate sections have been allotted for each machine. Each section is complete; therefore, no relevant information is missed by reading only the section for the machine of interest. Also, when components for both machines are similar, both machines have been combined into one section. This is done so that the reader interested in both machines need not read the same information twice.

Brach, David; Dube, John; Kelly, Jon; Peterson, Joanna; Bollig, John; Gohr, Lisa; Mahoney, Kamin; Polidori, Dave

1992-05-01

121

Novel Actin-like Filament Structure from Clostridium tetani*  

PubMed Central

Eukaryotic F-actin is constructed from two protofilaments that gently wind around each other to form a helical polymer. Several bacterial actin-like proteins (Alps) are also known to form F-actin-like helical arrangements from two protofilaments, yet with varied helical geometries. Here, we report a unique filament architecture of Alp12 from Clostridium tetani that is constructed from four protofilaments. Through fitting of an Alp12 monomer homology model into the electron microscopy data, the filament was determined to be constructed from two antiparallel strands, each composed of two parallel protofilaments. These four protofilaments form an open helical cylinder separated by a wide cleft. The molecular interactions within single protofilaments are similar to F-actin, yet interactions between protofilaments differ from those in F-actin. The filament structure and assembly and disassembly kinetics suggest Alp12 to be a dynamically unstable force-generating motor involved in segregating the pE88 plasmid, which encodes the lethal tetanus toxin, and thus a potential target for drug design. Alp12 can be repeatedly cycled between states of polymerization and dissociation, making it a novel candidate for incorporation into fuel-propelled nanobiopolymer machines.

Popp, David; Narita, Akihiro; Lee, Lin Jie; Ghoshdastider, Umesh; Xue, Bo; Srinivasan, Ramanujam; Balasubramanian, Mohan K.; Tanaka, Toshitsugu; Robinson, Robert C.

2012-01-01

122

Influence of slot and pole number combination on radial force and vibration modes in fractional slot PM brushless machines having single- and double-layer windings  

Microsoft Academic Search

This paper systematically investigates the radial force and vibration modes in fractional slot surface-mounted permanent magnet (PM) brushless machines having different slot and pole numbers, viz. 2p = Ns plusmn 2 , 2p = Ns plusmn1, q = 0.5, respectively, with either single- or double-layer winding. The dominant vibration mode can be determined from the lowest order of radial force

Z. Q. Zhu; Z. P. Xia; L. J. Wu; G. W. Jewell

2009-01-01

123

Machining of fiber reinforced composites  

NASA Astrophysics Data System (ADS)

Factors involved in machining of fiber-reinforced composites are reviewed. Consideration is given to properties of composites reinforced with boron filaments, glass fibers, aramid fibers, carbon fibers, and silicon carbide fibers and to polymer (organic) matrix composites, metal matrix composites, and ceramic matrix composites, as well as to the processes used in conventional machining of boron-titanium composites and of composites reinforced by each of these fibers. Particular attention is given to the methods of nonconventional machining, such as laser machining, water jet cutting, electrical discharge machining, and ultrasonic assisted machining. Also discussed are safety precautions which must be taken during machining of fiber-containing composites.

Komanduri, Ranga; Zhang, Bi; Vissa, Chandra M.

124

Dynamic supercoiling bifurcations of growing elastic filaments  

NASA Astrophysics Data System (ADS)

Certain bacteria form filamentous colonies when the cells fail to separate after dividing. In Bacillus subtilis, Bacillus thermus, and Cyanobacteria, the filaments can wrap into complex supercoiled structures as the cells grow. The structures may be solenoids or plectonemes, with or without branches in the latter case. Any microscopic theory of these morphological instabilities must address the nature of pattern selection in the presence of growth, for growth renders the problem nonautonomous and the bifurcations dynamic. To gain insight into these phenomena, we formulate a general theory for growing elastic filaments with bending and twisting resistance in a viscous medium, and study an illustrative model problem: a growing filament with preferred twist, closed into a loop. Growth depletes the twist, inducing a twist strain. The closure of the loop prevents the filament from unwinding back to the preferred twist; instead, twist relaxation is accomplished by the formation of supercoils. Growth also produces viscous stresses on the filament which even in the absence of twist produce buckling instabilities. Our linear stability analysis and numerical studies reveal two dynamic regimes. For small intrinsic twist the instability is akin to Euler buckling, leading to solenoidal structures, while for large twist it is like the classic writhing of a twisted filament, producing plectonemic windings. This model may apply to situations in which supercoils form only, or more readily, when axial rotation of filaments is blocked. Applications to specific biological systems are proposed.

Wolgemuth, Charles W.; Goldstein, Raymond E.; Powers, Thomas R.

2004-04-01

125

Modeling and simulation of variable speed constant frequency wind power generation system with doubly fed brushless machine  

Microsoft Academic Search

The variable speed constant frequency (VSCF) wind power generating system with doubly fed brushless generator (DFBG) has the advantage of high reliability and high efficiency. This paper introduces the structure of DFBG and the composition of VSCF wind power generating system with DFBG. The coupling inductance parameters of DFBG are also given and analyzed. Based on MATLAB\\/SIMULINK technology, the simulation

Fengge Zhang; Ningze Tong; Huijun Wang; Wenjun Li; Fengxiang Wang

2004-01-01

126

Comparison of 5th order and 3rd order machine models for doubly fed induction generator (DFIG) wind turbines  

Microsoft Academic Search

With increasing concern over climate change, a number of countries have implemented new renewable energy targets, which require significant amounts of wind generation. It is now recognized that much of this new wind generation plant will be variable speed type using doubly fed induction generators (DFIG). In order to investigate the impacts of these DFIG installations on the operation and

J. B. Ekanayake; L. Holdsworth; N. Jenkins

2003-01-01

127

Advances in the development of synchronous machines with high-temperature superconducting field winding at Siemens AG  

Microsoft Academic Search

Synchronous machines employing high-temperature superconductors offer several significant advantages compared to conventional ones. The development of superconducting electrical machines has a long tradition within Siemens AG. Starting with low-temperature superconducting materials in the 1970s, more than 30 years of experience in the field of superconducting electrical machinery have been accumulated. This knowledge represents the foundation for current research and development

Gunar Klaus; Wolfgang Nick; Heinz-Werner Neumüller; Georg Nerowski; William McCown

2006-01-01

128

Feasibility Study of Filament Wound Composite Road Wheel.  

National Technical Information Service (NTIS)

The feasibility of fabricating a M113 composite road wheel by the filament winding process has been demonstrated. Theoretical results, showing road wheel deformation where subjected to a radial compression load, have been obtained for both the conventiona...

G. D'Andrea P. G. O'Hara P. J. Croteau

1976-01-01

129

Model for supercoiling dynamics of growing filaments  

NASA Astrophysics Data System (ADS)

Growing filamentous colonies of bacteria can wrap into complex supercoiled structures. Fibers of cells of B. subtilis, B. thermus, cyanobacteria, and other species exhibit helical and plectonemic shapes. To elucidate the dynamics underlying the formation of these patterns, we formulate a general theory for growing elastic filaments with bending and twisting energy in a viscous medium. We focus on a model case of a growing filament with preferred twist, closed into a loop. Growth tends to deplete the twist, inducing a twist strain. Since the closure of the loop prevents the filament from winding back to its preferred twist, the twist strain can only be relieved by the formation of supercoils. We study this process using linear stability analysis and numerical simulations. Our model applies to situations in which supercoils form only, or more readily, when rotation is blocked.

Wolgemuth, Charles; Goldstein, Raymond; Powers, Thomas

2003-03-01

130

Simulation study of permanent magnet synchronous machine direct drive wind power generator using three level NPC converter system  

Microsoft Academic Search

In this paper, two three-phase three-level neutral point clamped (NPC) converters connected back-to-back are used for a direct drive wind power generator. A permanent magnet synchronous generator (PMSG) is used as the generator, which is driven by the wind turbine. Main problem of voltage unbalance in each electrolyte capacitor is controlled by using a simple chopper control circuit. A simple

Ranjan K. Behera; Wenzhong Gao; Olorunfemi Ojo

2009-01-01

131

Lens Intermediate Filaments  

PubMed Central

The ocular lens assembles two separate Intermediate Filament systems sequentially with differentiation. Canonical 8–11 nm IFs composed of Vimentin are assembled in lens epithelial cells and younger fiber cells, while the fiber cell-specific Beaded Filaments are switched on as fiber cell elongation initiates. Some of the key features of both filament systems are reviewed.

2009-01-01

132

Wind Energy: An Engineering Survey  

Microsoft Academic Search

This paper presents an extensive survey of literature about wind energy and wind machines, their design and their applications. The paper intends to provide those who plan for energy policy with thorough information about this renewable type of energy and the available machines that convert wind energy into useful mechanical or electrical work. The machines which are available at present

M. N. NAHAS; A. S. MOHAMAD; M. AKYURT; A. K. EL-KALAY

1987-01-01

133

On-line monitoring of partial discharges on stator winding of large rotating machines in the petrochemical environment  

SciTech Connect

This paper describes a joint collaboration program between a major large machine manufacturer and a petrochemical manufacturer to investigate the effectiveness of time- and frequency-domain techniques for on-line monitoring of the health of high-voltage machine stator insulation systems. Information is given on the factory and site testing carried out, as well as on the analysis and discussion of the results. It is concluded that both techniques can be used in the petrochemical environment for general assessments, but the time-domain technique is required if identification of specific locations of discharge sites is needed.

Bethge, A. [Siemens AG, Berlin (Germany); Lo, P.K.W. [Imperial Oil Ltd., Sarnia, Ontario (Canada). Products and Chemical Div.; Phillipson, J.T. [Exxon Chemical Co., Southampton (United Kingdom); Weidner, J.R. [Siemens AG, Muelheim (Germany)

1998-11-01

134

A three-start helical sheath on the flagellar filament of Caulobacter crescentus.  

PubMed Central

An unusual feature in preparations of the Caulobacter crescentus flagellar filaments is that some filaments are surrounded by a set of three windings that form a sheath. We provide evidence that the sheath is composed of subunits having a molecular mass of 24,000 Da. We suggest that the sheath could be composed of protofilaments of flagellin wound around the filament. Images

Trachtenberg, S; DeRosier, D J

1992-01-01

135

The signature of cyclonic PV filaments in the lower stratosphere  

NASA Astrophysics Data System (ADS)

The perturbation temperature and wind fields induced by a given zonally invariant potential vorticity (PV) filament in an isothermal atmosphere with uniform westerly background flow is investigated using a two-dimensional isentropic semigeostrophic model. Such PV filaments are commonplace in the lower midlatitude and polar stratosphere during winter and spring. The model is formulated in isentropic geostrophic coordinates because this formulation greatly simplifies the equations of motion describing the system. Given the potential vorticity distribution, the dynamics of the filament problem are obtained by inverting a single nonlinear elliptic equation. The model diagnoses relatively cool air below and relatively warm air above cyclonic filaments. In the case of anticyclonic filaments, air above the filament is cooler and air below the filament is warmer than the ambient air. The thermal perturbations in an isothermal atmosphere are sensitive to vertical gradients in PV, while the zonal along-filament flow associated with PV filaments is sensitive to quasi-horizontal PV gradients. If the PV anomaly marking the stratospheric filament is weak compared to ambient PV values, the magnitude of the thermal perturbations in the isothermal atmosphere is a linear function of the magnitude of the PV anomaly. In principle, it is possible to remotely detect the thermal signature of PV filaments using a Microwave Temperature Profiler (MTP), for example. This instrument, mounted aboard an aircraft flying in the lower stratosphere, can measure vertical profiles of the thermal structure below and above the flight track.

Richter, Harald; Atkinson, Roger J.

1999-10-01

136

Nonisothermal filaments in equilibrium  

NASA Astrophysics Data System (ADS)

Context. The physical properties of the so-called Ostriker isothermal filament have been classically used as a benchmark to interpret the stability of the filaments observed in nearby clouds. However, recent continuum studies have shown that the internal structure of the filaments depart from the isothermality, typically exhibiting radially increasing temperature gradients. Aims: The presence of internal temperature gradients within filaments suggests that the equilibrium configuration of these objects should be therefore revisited. The main goal of this work is to theoretically explore how the equilibrium structure of a filament changes in a nonisothermal configuration. Methods: We solve the hydrostatic equilibrium equation by assuming temperature gradients similar to those derived from observations. Results: We obtain a new set of equilibrium solutions for nonisothermal filaments with both linear and asymptotically constant temperature gradients. For sufficiently large internal temperature gradients, our results show that a nonisothermal filament could present significantly larger masses per unit length and shallower density profiles than the isothermal filament without collapsing by its own gravity. Conclusions: We conclude that filaments can reach an equilibrium configuration under nonisothermal conditions. Detailed studies of both the internal mass distribution and temperature gradients within filaments are then needed to judge the physical state of filaments.

Recchi, S.; Hacar, A.; Palestini, A.

2013-10-01

137

PERFORMANCE EVALUATION OF PERMANENT MAGNET SYNCHRONOUS MACHINES WITH CONCENTRATED AND DISTRIBUTED WINDINGS INCLUDING THE EFFECT OF FIELD-WEAKENING  

Microsoft Academic Search

p T T i m e p e r i o d ( s ) t T i m e ( s ) ABSTRACT U P h a s e v o l t a g e ( V ) max U Maximum line-line voltage, RMS (V) The aim of this paper is to evaluate different concentrated fractional pitch winding

Freddy Magnussen; Peter Thelin; Chandur Sadarangani

138

The Cooling of Electric Machines  

Microsoft Academic Search

The elevation in temperature of the windings of any electric machine due to the internal heat losses is usually the dominating factor in limiting the rating of the machine. This limitation found in the heating, is primarily due to the effects of high temperatures on the various types of insulation used in such machines. The American Institute of Electrical Engineers

George E. Luke

1923-01-01

139

Practical Stability of a Reluctance Synchronous Machine.  

National Technical Information Service (NTIS)

The ideal reluctance synchronous machine with dual rotor windings is modeled mathematically and simulated on a digital computer. In addition, it is demonstrated that practical stability of the machine exists when the Liapunov theorem requirements have bee...

W. U. Borger

1975-01-01

140

Wind at Work.  

ERIC Educational Resources Information Center

Describes a project in which students create wind machines to harness the wind's power and do mechanical work. Demonstrates kinetic and potential energy conversions and makes work and power calculations meaningful. Students conduct hands-on investigations with their machines. (DDR)

Adams, Stephen

1998-01-01

141

Wind at Work.  

ERIC Educational Resources Information Center

|Describes a project in which students create wind machines to harness the wind's power and do mechanical work. Demonstrates kinetic and potential energy conversions and makes work and power calculations meaningful. Students conduct hands-on investigations with their machines. (DDR)|

Adams, Stephen

1998-01-01

142

Organelles of Filamentous Fungi  

Microsoft Academic Search

Filamentous fungi are typical eukaryotes in many respects and contain a wide range of membrane-bounded subcellular compartments\\u000a which are the sites of specialised functions. These are organelles as defined by the possession of a bounding membrane. Filamentous\\u000a fungi contain all the major organelles with the key exception of the chloroplast, which is absent from all of these non-photosynthetic\\u000a organisms. In

P. Markham

143

Simple Fatigue Machine for Wires and Foils  

Microsoft Academic Search

A simple fatigue machine suitable for testing wires, filaments, foils, and other specimens of small cross section has been designed and built. The axial-load machine applies an alternating stress about a tensile mean stress and is of the constant amplitude of force type utilizing electromagnetic loading. One data curve for commercially pure titanium wire is presented to demonstrate the performance

R. L. Benedetti; D. L. Creighton

1970-01-01

144

Lab 6 winding facility  

SciTech Connect

This note describes the winding machine installed by the facility support group at lab 6 in the Fermilab village. It is available for use by outside users and groups within the lab. The machine can wind wire planes whose longest dimension is less than 10 feet. The Wire spacing range has an upper practical limit of about 5mm. Spacing beyond this requires a very long index time and therefore slows down the winding speed prohibitively.

Guerra, J.; Hansen, S.; Mangene, C.

1983-02-02

145

Filament-Filament Switching Can Be Regulated by Separation Between Filaments Together with Cargo Motor Number  

PubMed Central

How intracellular transport controls the probability that cargos switch at intersections between filaments is not well understood. In one hypothesis some motors on the cargo attach to one filament while others attach to the intersecting filament, and the ensuing tug-of-war determines which filament is chosen. We investigate this hypothesis using 3D computer simulations, and discover that switching at intersections increases with the number of motors on the cargo, but is not strongly dependent on motor number when the filaments touch. Thus, simply controlling the number of active motors on the cargo cannot account for in vivo observations that found reduced switching with increasing motor number, suggesting additional mechanisms of regulation. We use simulations to show that one possible way to regulate switching is by simultaneously adjusting the separation between planes containing the crossing filaments and the total number of active motors on the cargo. Heretofore, the effect of filament-filament separation on switching has been unexplored. We find that the switching probability decreases with increasing filament separation. This effect is particularly strong for cargos with only a modest number of motors. As the filament separation increases past the maximum head-to-head distance of the motor, individual motors walking along a filament will be unable to reach the intersecting filament. Thus, any switching requires that other motors on the cargo attach to the intersecting filament and haul the cargo along it, while motor(s) engaged on the original filament detach. Further, if the filament separation is large enough, the cargo can have difficulty proceeding along the initial filament because the engaged motors can walk underneath the intersecting filament, but the cargo itself cannot fit between the filaments. Thus, the cargo either detaches entirely from the original filament, or must dip to the side of the initial filament and then pass below the crossing filament.

Erickson, Robert P.

2013-01-01

146

Field control for wind-driven generators  

SciTech Connect

The field current of a wind-driven generator is automatically controlled in response to a first signal representing the wind speed and a second signal representing the impeller tip speed so as to continuously load the wind machine to the extent necessary for maintaining a constant tip speed/wind speed ratio, thereby optimizing the performance of the machine.

Andrew, J.F.; Soderholm, L.H.

1982-05-25

147

Field control for wind-driven generators  

SciTech Connect

The field current of a wind-driven generator is automatically controlled in response to a first signal representing the wind speed and a second signal representing the impeller tip speed so as to continuously load the wind machine to the extent necessary for maintaining a constant tip speed/wind speed ratio, thereby optimizing the performance of the machine.

Soderholm, L.H.; Andrew, J.F.

1980-10-03

148

Wind Power Now!  

ERIC Educational Resources Information Center

|The government promotes and heavily subsidizes research in nuclear power plants. Federal development of wind power is slow in comparison even though much research with large wind-electric machines has already been conducted. Unless wind power programs are accelerated it will not become a major energy alternative to nuclear power. (MR)|

Inglis, David Rittenhouse

1975-01-01

149

Aeroelastic wind energy converter  

Microsoft Academic Search

The principle of aeroelastic wind energy conversion is introduced and an H-section model which works on the basis of torsional aeroelastic instability is described. A mathematical formulation for the prediction of the power coefficient of such wind machines is presented. A small model is constructed and tested in a wind tunnel. Although the efficiency of the model was very low,

G. Ahmadi

1978-01-01

150

Power from the Wind  

ERIC Educational Resources Information Center

|Wind energy is the fastest-growing renewable energy source in the world. Over the last 20 years, the wind industry has done a very good job of engineering machines, improving materials, and economies of production, and making this energy source a reality. Like all renewable energy forms, wind energy's successful application is site specific.…

Roman, Harry T.

2004-01-01

151

Wind Power Now!  

ERIC Educational Resources Information Center

The government promotes and heavily subsidizes research in nuclear power plants. Federal development of wind power is slow in comparison even though much research with large wind-electric machines has already been conducted. Unless wind power programs are accelerated it will not become a major energy alternative to nuclear power. (MR)

Inglis, David Rittenhouse

1975-01-01

152

Simple Machines  

NSDL National Science Digital Library

This activity is designed to learn about simple machines and to have fun doing so! First, use this website to learn backround information on the basics of simple machines. Try the quiz! Simple Machines Learning Site Next, play a game that tests your ability to identify simple machines.... Edheads: Simple Machines Finally, view this video to see how students your age used applied simple machines to do a cool task... Building Simple Machines: A Glass of Milk, Please ...

Awol

2006-11-15

153

Method for preparing metallated filament-wound structures  

DOEpatents

Metallated graphite filament-wound structures are prepared by coating a continuous multi-filament carbon yarn with a metal carbide, impregnating the carbide coated yarn with a polymerizable carbon precursor, winding the resulting filament about a mandrel, partially curing the impregnation in air, subjecting the wound composite to heat and pressure to cure the carbon precursor, and thereafter heating the composite in a sizing die at a pressure loading of at least 1000 psi for graphitizing the carbonaceous material in the composite. The carbide in the composite coalesces into rod-like shapes which are disposed in an end-to-end relationship parallel with the filaments to provide resistance to erosion in abrasive laden atmospheres.

Peterson, George R. (Knoxville, TN)

1979-01-01

154

Introspective Machine.  

National Technical Information Service (NTIS)

An introspective machine, capable of passing judgment on its own deductive performances, is modelled and analyzed. First, the class of ideal machines which is provided with unlimited resources is studied. Since ideal introspective machines are usually unf...

G. A. W. Vreeswijk

1989-01-01

155

Thigmonasticity of thistle staminal filaments  

Microsoft Academic Search

Summary Touching stimulates thistle (Cirsium horridulum Michx.) staminal filaments to rapidly shorten to approximately 70% of their original length. The filaments subsequently re-elongate and regain contractibility within 10min. This thigmonastic movement can be repeated at least 10 times in detached flowers. Filament length is reduced by bathing in 1 M sorbitol, indicating that length change depends on variation in turgor

T. C. Pesacreta; Victoria I. Sullivan; K. H. Hasenstein; J. M. Durand

1991-01-01

156

Filament depolymerisation by motor proteins  

Microsoft Academic Search

Many active processes in cells are driven by highly specialized motor proteins, which interact with filaments of the cytoskeleton. Members of the Kin-13 kinesin subfamily are able to interact specifically with filament ends and induce depolymerisation of the filaments ends. Recent in vitro assays and single molecule studies have shown, that MCAK accumulates at both ends of stabilized microtubules and

Gernot Klein

2005-01-01

157

Scanning Doppler Lidar Measurements for Wind Energy Applications  

Microsoft Academic Search

The development of wind energy has increased rapidly along with the size and capacity of wind turbines. These larger machines require detailed wind resource measurements at higher and higher altitudes. Accurate wind speed, wind direction, and turbulence statistics are required for wind resource assessment and efficient wind farm operation. Tower measurements are limited in coverage and do not provide the

R. Frehlich; N. Kelley

2008-01-01

158

Machine Shop Grinding Machines.  

ERIC Educational Resources Information Center

|This curriculum manual is one in a series of machine shop curriculum manuals intended for use in full-time secondary and postsecondary classes, as well as part-time adult classes. The curriculum can also be adapted to open-entry, open-exit programs. Its purpose is to equip students with basic knowledge and skills that will enable them to enter…

Dunn, James

159

Machine Shop Grinding Machines.  

ERIC Educational Resources Information Center

This curriculum manual is one in a series of machine shop curriculum manuals intended for use in full-time secondary and postsecondary classes, as well as part-time adult classes. The curriculum can also be adapted to open-entry, open-exit programs. Its purpose is to equip students with basic knowledge and skills that will enable them to enter the…

Dunn, James

160

The Filament Feeding Mechanism  

Microsoft Academic Search

\\u000a Now that your Extruder is complete, it’s time to bolt it onto your 3D printer frame. Your 3D printer works by feeding a plastic\\u000a filament into the heater core of the Extruder. The plastic melts and is then forced through the Extruder’s nozzle and applied\\u000a to the worktable to print three dimensional objects.

Patrick Hood-Daniel; James Floyd Kelly

161

Filament heater current modulation for increased filament lifetime  

SciTech Connect

The surface conversion H-minus ion source employs two 60 mil tungsten filaments which are approximately 17 centimeters in length. These filaments are heated to approximately 2,800 degrees centigrade by 95--100 amperes of DC heater current. The arc is struck at a 120 hertz rate, for 800 microseconds and is generally run at 30 amperes peak current. Although sputtering is considered a contributing factor in the demise of the filament, evaporation is of greater concern. If the peak arc current can be maintained with less average heater current, the filament evaporation rate for this arc current will diminish. In the vacuum of an ion source, the authors expect the filaments to retain much of their heat throughout a 1 millisecond (12% duty) loss of heater current. A circuit to eliminate 100 ampere heater currents from filaments during the arc pulse was developed. The magnetic field due to the 100 ampere current tends to hold electrons to the filament, decreasing the arc current. By eliminating this magnetic field, the arc should be more efficient, allowing the filaments to run at a lower average heater current. This should extend the filament lifetime. The circuit development and preliminary filament results are discussed.

Paul, J.D.; Williams, H.E. III

1996-06-01

162

Analytical expressions for maximum wind turbine average power in a Rayleigh wind regime  

SciTech Connect

Average or expectation values for annual power of a wind turbine in a Rayleigh wind regime are calculated and plotted as a function of cut-out wind speed. This wind speed is expressed in multiples of the annual average wind speed at the turbine installation site. To provide a common basis for comparison of all real and imagined turbines, the Rayleigh-Betz wind machine is postulated. This machine is an ideal wind machine operating with the ideal Betz power coefficient of 0.593 in a Rayleigh probability wind regime. All other average annual powers are expressed in fractions of that power. Cases considered include: (1) an ideal machine with finite power and finite cutout speed, (2) real machines operating in variable speed mode at their maximum power coefficient, and (3) real machines operating at constant speed.

Carlin, P.W.

1996-12-01

163

The acquisition of wind rights for wind energy development  

NASA Astrophysics Data System (ADS)

Identifying suitable sites for large wind machine clusters, or wind farms, requires more than finding a location with an adequate wind resource. Consideration must also be given to the question of how land use policies and regulations will affect the siting of wind system installations. In particular, the issue of acquiring wind rights or guaranteed access to the wind resource for electric power generation, will be vital to the development of wind energy. Several methods are examined for acquiring and preserving access to the wind resource and for dealing with related land use issues.

Noun, R. J.

1982-03-01

164

Interplanetary shocks preceded by solar filament eruptions  

SciTech Connect

We discuss the solar and interplanetary characteristics of six interplanetary shock and energetic particle events associated with the eruptions of solar filaments lying outside active regions. The events are characterized by the familiar double-ribbon H..cap alpha.. brightenings observed with large flares, but only very weak soft X ray and microwave bursts. Both impulsive phases and metric type II bursts are absent in all six events. The energetic particles observed near the earth appear to be accelerated predominantly in the interplanetary shocks. The interplanetary shock speeds are lower and the longitudinal extents considerably less than those of flare-associated shocks. Three of the events were associated with unusual enhancements of singly ionized helium in the solar wind following the shocks. These enhancements appear to be direct detections of the cool filament material expelled from the corona. We suggest that these events are part of a spectrum of solar eruptive events which include both weaker events and large flares. Despite their unimpressive and unreported solar signatures, the quiescent filament eruptions can result in substantial space and geophysical disturbances.

Cane, H.V.; Kahler, S.W.; Sheeley Jr., N.R.

1986-12-01

165

Machine Learning  

Microsoft Academic Search

Machine learning is a very active sub-field of artificial intelligence concerned with the development of computational models\\u000a of learning. Machine learning is inspired by the work in several disciplines: cognitive sciences, computer science, statistics,\\u000a computational complexity, information theory, control theory, philosophy, and biology. Simply speaking, machine learning is\\u000a learning by machine. From a computational point of view, machine learning refers

Xin Yao; Yong Liu

166

CVD-produced boron filaments  

SciTech Connect

A technique for producing boron filaments with an average tensile strength of 6.89 GPa has been developed which involves longitudinal splitting of the filament and core (substrate) removal by etching. Splitting is accomplished by a pinch wheel device which continuously splits filaments in lengths of 3.0 m by applying a force to the side of the filament to create a crack which is then propagated along the axis by a gentle sliding action. To facilitate the splitting, a single 10 mil tungsten substrate is used instead of the usual 0.5 mil substrate. A solution of hot 30% hydrogen peroxide is used to remove the core without attacking the boron. An alternative technique is to alter the residual stress by heavily etching the filament. Average strengths in the 4.83-5.52 GPa range have been obtained by etching an 8 mil filament to 4 mil.

Wawner, F.E. (Virginia, University, Charlottesville, Va.); Debolt, H.E. (Avco Corp., Avco Specialty Materials Div., Lowell, Mass.)

1980-07-01

167

Intermediate Filament Diseases: Desminopathy  

PubMed Central

Desminopathy is one of the most common intermediate filament human disorders associated with mutations in closely interacting proteins, desmin and alphaB-crystallin. The inheritance pattern in familial desminopathy is characterized as autosomal dominant or autosomal recessive, but many cases have no family history. At least some and likely most sporadic desminopathy cases are associated with de novo DES mutations. The age of disease onset and rate of progression may vary depending on the type of inheritance and location of the causative mutation. Typically, the illness presents with lower and later upper limb muscle weakness slowly spreading to involve truncal, neck-flexor, facial and bulbar muscles. Skeletal myopathy is often combined with cardiomyopathy manifested by conduction blocks, arrhythmias and chronic heart failure resulting in premature sudden death. Respiratory muscle weakness is a major complication in some patients. Sections of the affected skeletal and cardiac muscles show abnormal fibre areas containing chimeric aggregates consisting of desmin and other cytoskeletal proteins. Various DES gene mutations: point mutations, an insertion, small in-frame deletions and a larger exon-skipping deletion, have been identified in desminopathy patients. The majority of these mutations are located in conserved alpha-helical segments, but additional mutations have recently been identified in the tail domain. Filament and network assembly studies indicate that most but not all disease-causing mutations make desmin assembly-incompetent and able to disrupt a pre-existing filamentous network in dominant-negative fashion. AlphaB-crystallin serves as a chaperone for desmin preventing its aggregation under various forms of stress; mutant CRYAB causes cardiac and skeletal myopathies identical to those resulting from DES mutations.

Goldfarb, Lev G.; Olive, Montse; Vicart, Patrick; Goebel, Hans H.

2009-01-01

168

Simple Machines  

NSDL National Science Digital Library

At this website, EdHeads, a nonprofit, offers five interactive, animated modules to educate second- through sixth-graders about simple machines. By identifying the many machines located throughout a house, students can learn about fulcrums, wheel and axles, levers, pulleys, inclined planes, and much more. The website is equipped with simple animations to help children understand how the machines work. After students have a handle on simple machines, they can begin to see how they work together to create compound machines. The website also provides a brief glossary summarizing nine types of simple machines. This site is also reviewed in the February 18, 2005_NSDL Physical Sciences Report_.

169

Use of split-disk tests for the process parameters of filament wound epoxy composite tubes  

Microsoft Academic Search

The aim of this study was to investigate processing parameters of continuous fiber reinforced epoxy composite tubes produced by the filament winding technique. For this purpose, split-disk tests (according to ASTM D-2290 standard) were performed for the specimens produced with two different epoxy resin systems, five different fiber materials and five different winding angles. By determining the hoop tensile strength

Cevdet Kaynak; E. Salim Erdiller; Levend Parnas; Fikret Senel

2005-01-01

170

Chaperonin filaments: The archael cytoskeleton  

SciTech Connect

Chaperonins are multi-subunit double-ring complexed composed of 60-kDa proteins that are believed to mediate protein folding in vivo. The chaperonins in the hyperthermophilic archaeon Sulfolobus shibatae are composed of the organism`s two most abundant proteins, which represent 4% of its total protein and have an intracellular concentration of {ge} 3.0 mg/ml. At concentrations of 1.0 mg/ml, purified chaperonin proteins aggregate to form ordered filaments. Filament formation, which requires Mg{sup ++} and nucleotide binding (not hydrolysis), occurs at physiological temperatures under conditions suggesting filaments may exist in vivo. If the estimated 4,600 chaperonins per cell, formed filaments in vivo, they could create a matrix of filaments that would span the diameter of an average S. shibatae cell 100 times. Direct observations of unfixed, minimally treated cells by intermediate voltage electron microscopy (300 kV) revealed an intracellular network of filaments that resembles chaperonin filaments produced in vitro. The hypothesis that the intracellular network contains chaperonins is supported by immunogold analyses. The authors propose that chaperonin activity may be regulated in vivo by filament formation and that chaperonin filaments may serve a cytoskeleton-like function in archaea and perhaps in other prokaryotes.

Trent, J.D.; Kagawa, H.K.; Yaoi, Takuro; Olle, E.; Zaluzec, N.J.

1997-08-01

171

Wind Energy Systems.  

ERIC Educational Resources Information Center

|During the 1920s and 1930s, millions of wind energy systems were used on farms and other locations far from utility lines. However, with passage of the Rural Electrification Act in 1939, cheap electricity was brought to rural areas. After that, the use of wind machines dramatically declined. Recently, the rapid rise in fuel prices has led to a…

Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

172

SIMPLE MACHINES  

NSDL National Science Digital Library

You will be learning about several types of simple machines. Have fun!! Review the first website (which is right here!! Simple machines) . It has information about simple machines. DON\\"T click until you read all directions!!! Prepare to discuss each type in class. You will need to take some basic notes about each machine, using a bubble-map format. Don\\'t forget ...

Machose, Mrs.

2007-03-10

173

State Machines  

Microsoft Academic Search

We are surrounded by real-world state machines: ballpoint pen retractor mechanisms, vending machines, washing-machine controllers, digital watches. They are a trivial but underused technology that can simplify how we implement programs that must track how they got to their current state before handling a new event. However, many programmers feel that state machines are only useful when they're developing communication

Dave Thomas; Andy Hunt

2002-01-01

174

Kid Machine  

NSDL National Science Digital Library

This activity is on page 3 (continued on page 2) of the pdf, part of the Simple Machines Discovery Box. In this fun activity, learners "create" a complex machine by simulating the parts in action. Learners move their bodies and make sounds as if they are individual parts of a moving machine. Then learners discover what happens when part of a machine is broken and problem solve ways to fix it.

Omsi

2004-01-01

175

Wind energy for human needs  

Microsoft Academic Search

Following a description of ancient windmills, the paper presents an economic and technological outlook into wind energy extraction possibilities. The difficulties in the utilization of the wind energy, like the low air density and the impossibility of effective channelization of the air stream, are pointed out and the physics and technology of wind machines are discussed together with the theory,

M. F. Merriam

1977-01-01

176

Simple Machines  

NSDL National Science Digital Library

This is an online activity about simple machines. Learners will try their hand at putting these amazing devices to work. They will use several simple machines to help "build" a tree house. This is an excellent activity to demonstrate how science - in particular, simple machines - are at work in our every day lives.

Cosi

2000-01-01

177

Electrostatic Machines  

NSDL National Science Digital Library

This website from Antonio Carlos M. De Queiroz, an associate professor at the Federal University of Rio de Janeiro, illustrates a number of different electrostatic machines. The site includes details and images of machines built by the professor as well as many other historical machines of this type. Some information is also available in Portugese.

De Queiroz, Antonio C.

2011-07-13

178

Otomycosis due to filamentous fungi.  

PubMed

Otomycosis is common throughout the world but barely studied in Spain. Our objective was to determine the microbiological and epidemiological characteristics of this pathology in Cadiz (Spain) between 2005 and 2010. Samples from patients with suspicion of otomycosis underwent a direct microscopic examination and culture on different media for fungi and bacteria. Mycological cultures were incubated at 30°C for at least seven days. Identification of fungi was based on colonial morphology and microscopic examination of fungal structure. From a total of 2,633 samples, microbial growth was present in 1,375 (52.2%) and fungal isolation in 390 (28.4%). We identified 228 yeasts and 184 filamentous fungi (13.4% of positive cultures and 47.2% of otomycosis), associated with yeasts in 22 cases (5.6%). The most frequent species were Aspergillus flavus (42.4%), A. niger (35.9%), A. fumigatus (12.5%), A. candidus (7.1%), A. terreus (1.6%), and Paecilomyces variotii (0.5%). Infection was predominant in men (54.9%) and patients beyond 55 years old (46.8%). The most common clinical symptoms were itching (98.9%), otalgia (59.3%), and hypoacusis (56.0%). Fall season reported the lowest number of cases (20.1%). Incidence of otomycosis and fungi producing otomycosis vary within the distinct geographical areas. In Cadiz, this infection is endemic due to warm temperatures, high humidity, sea bathing, and wind, which contributes to disseminate the conidia. Despite Aspergillus niger has been reported as the main causative agent, A. flavus is predominant in Cadiz. Although infection is usually detected in warm months, we observed a homogeneous occurrence of otomycosis in almost all the seasons. PMID:21499908

García-Agudo, Lidia; Aznar-Marín, Pilar; Galán-Sánchez, Fátima; García-Martos, Pedro; Marín-Casanova, Pilar; Rodríguez-Iglesias, Manuel

2011-04-17

179

Regulated DC power generation using mixed-pole synchronous reluctance machines  

Microsoft Academic Search

This paper presents an innovative DC power generator scheme using the mixed-pole synchronous reluctance machine having two stator windings. The power windings deliver the DC power to the load, with the control windings acting as the vehicle for excitation. The excitation process is established by connecting the generated DC voltage to the machine's secondary windings through a DC-DC buck converter.

Olorunfemi Ojo; Zhiqing Wu

1997-01-01

180

Thigmonasticity of thistle staminal filaments  

Microsoft Academic Search

Investigations of the longitudinal distribution of the extensibility of staminal filaments of the common thistle (Cirsium horridulum Michx.) showed that the base of the filaments (attachment to corolla) is almost twice as elastic as the apical portion (next to anthers). Boiling leads to a more uniform distribution of extensibility. Using a stress-strain analyzer we investigated the elastic properties of fresh,

Karl H. Hasenstein; Thomas C. Pesacreta; Victoria I. Sullivan

1993-01-01

181

Surface manipulation of protein filaments  

NASA Astrophysics Data System (ADS)

Within mammalian tissues, cells move by actively remodeling a dense network of collagen fibrils. In order to study this situation, we analyze the force response of two types of filamentous protein structures, desmin intermediate filaments 12 nm in diameter and collagen fibrils 80 nm in diameter. Both types of filaments were adsorbed at a solid-liquid interface and locally moved with an AFM tip at constant velocity against surface friction in the interfacial plane. In the case of collagen fibrils, that have an extensibility below 30% extension, we observed that microns long fibrils could be moved by the tip and deformed into shapes that could not be explain by the linear elastic theory for a stiff rod. In the case of desmin filaments that can be stretched up to 3.5 times there length, we observed local stretching of the filaments and discreet steps in the torsional force measured with the cantilever. In order to describe both types of filaments' behaviors, we described the protein filaments as a chain of beads of mass m linked together by a mass-less polymer linker. By solving the Newtonian equations of motions for the coupled beads in the presence of a point load and a viscous drag due to the surface-filament interactions we were able to reproduced our experimental data and extract information on friction.

Kreplak, Laurent; Staple, Douglas; Loparic, Marko; Kreuzer, Hans-Juergen

2009-03-01

182

Development of Filament-Reinforced Metals.  

National Technical Information Service (NTIS)

An investigation was conducted to develop filament-reinforced metals for use at elevated temperatures. The use of carbon filaments to reinforce nickel, cobalt, aluminum and platinum, and the use of silicon carbide filaments to reinforce aluminum and nicke...

D. E. Niesz C. W. Kistler J. N. Fleck

1967-01-01

183

A Bipolar Spindle Of Antiparallel ParM Filaments Drives Bacterial Plasmid Segregation  

PubMed Central

To ensure their stable inheritance by daughter cells during cell division, bacterial low copy-number plasmids make simple DNA segregating machines that use an elongating protein filament between sister plasmids. In the ParMRC system of Escherichia coli R1 plasmid, ParM, an actin-like protein, forms the spindle between ParRC complexes on sister plasmids. Using a combination of structural work and total internal reflection fluorescence microscopy, we show that ParRC bound and could accelerate growth at only one end of polar ParM filaments, mechanistically resembling eukaryotic formins. The architecture of ParM filaments enabled two ParRC-bound filaments to associate in an antiparallel orientation, forming a bipolar spindle. The spindle elongated as a bundle of at least two antiparallel filaments, thereby pushing two plasmid clusters towards the poles.

Gayathri, P.; Fujii, T.; M?ller-Jensen, J.; van den Ent, F.; Namba, K.; Lowe, J.

2013-01-01

184

A bipolar spindle of antiparallel ParM filaments drives bacterial plasmid segregation.  

PubMed

To ensure their stable inheritance by daughter cells during cell division, bacterial low-copy-number plasmids make simple DNA segregating machines that use an elongating protein filament between sister plasmids. In the ParMRC system of the Escherichia coli R1 plasmid, ParM, an actinlike protein, forms the spindle between ParRC complexes on sister plasmids. By using a combination of structural work and total internal reflection fluorescence microscopy, we show that ParRC bound and could accelerate growth at only one end of polar ParM filaments, mechanistically resembling eukaryotic formins. The architecture of ParM filaments enabled two ParRC-bound filaments to associate in an antiparallel orientation, forming a bipolar spindle. The spindle elongated as a bundle of at least two antiparallel filaments, thereby pushing two plasmid clusters toward the poles. PMID:23112295

Gayathri, P; Fujii, T; Møller-Jensen, J; van den Ent, F; Namba, K; Löwe, J

2012-10-25

185

Wind power and other energy options  

Microsoft Academic Search

Past experience with wind power is considered along with the mechanics of wind energy conversion, small wind-power installations, large wind-power machines and installations, other solar-related energy sources, geophysical energy sources, nuclear power from fission, nuclear power from fusion, a comparison of dollar costs of wind power and nuclear power, social costs of wind power and nuclear power, and the choice

D. R. Inglis

1978-01-01

186

Wind power and other energy options  

Microsoft Academic Search

Past experience with wind power is considered along with the mechanics of wind energy conversion, small wind-power installations, large wind-power machines and installations, other solar-related energy sources, geophysical energy sources, nuclear power from fission, nuclear power from fusion, a comparison of dollar costs of wind power and nuclear power, social costs of wind power and nuclear power, and the choice

Inglis

1979-01-01

187

Operation of a third generation wind turbine  

Microsoft Academic Search

A modern wind turbine was installed on May 26, 1982, at the USDA Conservation and Production Research Laboratory, Bushland, Texas. This wind machine was used to provide electrical energy for irrigation pumping and other agricultural loads. The wind turbine purchased for this research is an Enertech Model 44, manufactured by Enertech Corporation, Norwich, Vermont. The horizontal-axis wind turbine has a

F. C. Vosper; R. N. Clark

1983-01-01

188

Effect of Number of Phases on Losses in Conducting Sleeves of Surface PM Machine Rotors Equipped With Fractional-Slot Concentrated Windings  

Microsoft Academic Search

High-speed machines with a solid rotor or a high- strength retaining sleeve could offer design and performance advantages. For a specific application, if the use of a high-strength nonmagnetic metallic retaining sleeve is more advantageous than a nonmetallic (e.g., carbon fiber) one, one needs to evaluate the eddy-current losses due to armature reaction space and time harmonics and\\/or tooth ripple,

Ayman M. EL-Refaie; Manoj R. Shah; Ronghai Qu; John M. Kern

2008-01-01

189

Intermediate Filaments: A Historical Perspective  

PubMed Central

Intracellular protein filaments intermediate in size between actin microfilaments and microtubules are composed of a surprising variety of tissue specific proteins commonly interconnected with other filamentous systems for mechanical stability and decorated by a variety of proteins that provide specialized functions. The sequence conservation of the coiled-coil, alpha-helical structure responsible for polymerization into individual 10 nm filaments defines the classification of intermediate filament proteins into a large gene family. Individual filaments further assemble into bundles and branched cytoskeletons visible in the light microscope. However, it is the diversity of the variable terminal domains that likely contributes most to different functions. The search for the functions of intermediate filament proteins has led to discoveries of roles in diseases of the skin, heart, muscle, liver, brain, adipose tissues and even premature aging. The diversity of uses of intermediate filaments as structural elements and scaffolds for organizing the distribution of decorating molecules contrasts with other cytoskeletal elements. This review is an attempt to provide some recollection of how such a diverse field emerged and changed over about 30 years.

Oshima, Robert G.

2007-01-01

190

Purification of native myosin filaments from muscle.  

PubMed Central

Analysis of the structure and function of native thick (myosin-containing) filaments of muscle has been hampered in the past by the difficulty of obtaining a pure preparation. We have developed a simple method for purifying native myosin filaments from muscle filament suspensions. The method involves severing thin (actin-containing) filaments into short segments using a Ca(2+)-insensitive fragment of gelsolin, followed by differential centrifugation to purify the thick filaments. By gel electrophoresis, the purified thick filaments show myosin heavy and light chains together with nonmyosin thick filament components. Contamination with actin is below 3.5%. Electron microscopy demonstrates intact thick filaments, with helical cross-bridge order preserved, and essentially complete removal of thin filaments. The method has been developed for striated muscles but can also be used in a modified form to remove contaminating thin filaments from native smooth muscle myofibrils. Such preparations should be useful for thick filament structural and biochemical studies.

Hidalgo, C; Padron, R; Horowitz, R; Zhao, F Q; Craig, R

2001-01-01

191

Dynamics of polarly driven filaments  

NASA Astrophysics Data System (ADS)

In this study we investigate the dynamics and transport of bio-polymers such as microtubules or actin filaments when driven by motor proteins. A slender-body hydrodynamic formulation is augmented by a model for the forcing from the motor proteins. Our results show that the spatial gradients in the polar forcing, or the detachment of the filament from the motor proteins, can lead to nontrivial shape dynamics (undulatory traveling waves), and random walk trajectories. The interaction between filament and the simple device geometries is investigated, as is the effect of thermal fluctuations.

Shelley, Michael; Young, Yuan-Nan

2009-11-01

192

Observations of Jovian polar auroral filaments  

NASA Astrophysics Data System (ADS)

In this paper we report a phenomenon hitherto unobserved in Jupiter's ultraviolet polar auroras, specifically thin (˜0.6° wide), long-lived quasi-sun-aligned polar auroral filaments (PAFs) of brightness ˜100 kR spanning the highly variable region poleward of the main oval. This observation, made using Hubble Space Telescope images, is significant since no coherent structures have previously been observed in Jupiter's very high latitude auroral region, and it may help shed light on the dynamics of Jupiter's under-explored magnetotail. PAFs have been observed in 4 sets of observations over 6 days in 2007, and their occurrence appears to be independent of impinging solar wind conditions. The feature comprises two components: the section toward noon remains fixed in orientation toward the sun, while the anti-sunward section rotates. We estimate overall rotation rates of ˜0-45% of corotation, values which may indicate the rotation rate of Jupiter's polar ionosphere and tail lobes.

Nichols, J. D.; Clarke, J. T.; Gérard, J. C.; Grodent, D.

2009-04-01

193

Kicking Machine  

NSDL National Science Digital Library

In this design challenge activity, learners build a machine that kicks a Ping-Pong ball into a cup lying on its side 12 inches away. Learners use a pendulum, a rubber band, or a combination of the two to do this and test the accuracy of their machines by shooting a Ping-Pong ball into a cup. Educators can use this activity to demonstrate simple machines and kinetic/potential energy. This activity can be followed up with "Extreme Kicking Machine" which adds an even greater challenge into the mix.

Wgbh

2010-01-01

194

Hot Filament Alignment System  

NASA Astrophysics Data System (ADS)

The ``a'' Correlation in Neutron Decay (aCORN) collaboration seeks to measure the electron-antineutrino correlation in free neutron decay to within 1% relative uncertainty as a test of the Standard Model. To accomplish this, two regions of the phase space of the decay must be isolated. The correlation parameter, ``little a,'' is proportional to the counting asymmetry between these two groups. Before the final measurement can be performed, an in-situ test of the alignment of the magnetic field and the experimental axis, set by a series of tungsten collimators, must be checked. Any misalignment would introduce an asymmetry in the experiment, resulting in an inaccurate ``little a'' measurement. To test the alignment a filament can be quickly inserted into the aCORN vacuum tube, which produces low energy electrons when heated. These electrons will travel nearly straight along the magnetic field lines due to their minimal cyclotron radius. A misalignment of the field can be determined from the relative currents detected on the final, segmented collimator. A description of the preliminary work on an in-situ alignment system will be presented.

Lamere, Edward

2010-11-01

195

The Fluid Foil: The Seventh Simple Machine  

ERIC Educational Resources Information Center

|A simple machine does one of two things: create a mechanical advantage (lever) or change the direction of an applied force (pulley). Fluid foils are unique among simple machines because they not only change the direction of an applied force (wheel and axle); they convert fluid energy into mechanical energy (wind and Kaplan turbines) or vice…

Mitts, Charles R.

2012-01-01

196

Secondary ELM Filaments in NSTX  

SciTech Connect

Filamentary structures are observed in the scrape-off layer of the National Spherical Torus Experime05nt during ELMs. While the primary filaments correspond to a direct result of the ELM event, the 'secondary' filaments which occur generally later but still within 1 ms of the ELM onset are observed to have the same characteristics as inter-ELM filaments (or blobs): poloidal auto-correlation lengths of similar to 4 cm, broadband frequency and poloidal wave number spectra and radial velocities of 1-2 km/s. At the same time, no MHD modes are observed during the phase in which secondary filaments are present. (C) 2009 Elsevier B.V. All rights reserved.

Maqueda, R. J. [Nova Photonics, Princeton, NJ; Maingi, Rajesh [ORNL; Ahn, J W [University of California, San Diego; NSTX Team, [Multiple Institutions

2009-01-01

197

Electromechanical interaction in a synchronous reluctance machine  

Microsoft Academic Search

Electromagnetic forces on a whirling rotor of a synchronous reluctance machine are studied using time-discretized 2D finite-element analysis. The whirling motion generates eccentricity harmonics in the air-gap field. These harmonics may further induce circulating currents in the windings of the machine. The dynamics of the induced currents is coupled with the dynamics of the rotor, especially, when the machine is

A. Arkkio; A. Sinervo

2010-01-01

198

Hybrid Excitation of the Axial Inductor Machine  

NASA Astrophysics Data System (ADS)

The paper considers the possibility to use permanent magnets in the rotor slots of axial inductor machine with the aim to create a hybrid excitation of such a machine - from the magnets and from the excitation winding which is placed between the stator cores. The hybrid excitation allows the weight and size parameters of the machine to be improved. Under consideration is a 32 kW under-carriage generator 2?B.13.Y1.

Orlova, S.; Pugachov, V.; Levin, N.

2012-01-01

199

Time and space harmonics in brushless doubly-fed machine  

Microsoft Academic Search

Brushless Doubly fed machines have two stator windings and an especial cage rotor. The main advantage of the machine is higher reliability in compare with DFIGs. Cross coupling is the mechanism, which provides indirect coupling of the two stator windings. In this paper, time and space harmonics in a BDFM are studied to find a criterion for evaluating different rotor

Hamed Gorginpour; Behzad Jandaghi; Hashem Oraee

2011-01-01

200

Intermediate filaments in nervous tissues  

Microsoft Academic Search

Intermediate filaments have been isolated from rabbit intradural spinal nerve roots by the axonal flotation method. This method was modified to avoid exposure of axons to low ionic strength medium. The purified filaments are morphologically 75-80% pure. The gel electrophoretogr am shows four major bands migrating at 200,000, 145,000, 68,000, and 60,000 daltons, respectively. A similar preparation from rabbit brain

RONALD K. H. LIEM; SHU-HUI YEN; GARY D. SALOMON; MICHAEL L. SHELANSKI

1978-01-01

201

The Electron Emission from Thoriated Tungsten Filaments  

Microsoft Academic Search

Electron emission from tungsten filaments containing thoria.-Ten years ago the erratic behavior of some tungsten filaments was traced to the thoria present and it was discovered that by suitable treatment the filaments, containing 1 to 2 per cent of thoria, could be activated so as to give an electron emission many thousand times that of a pure tungsten filament at

Irving Langmuir

1923-01-01

202

Machine intelligence  

Microsoft Academic Search

Under certain conditions, we appear willing to see and interact with computing machines as though they exhibited intelligence, at least an intelligence of sorts. Using exam- ples from AI and robotics research, as well as a selection of relevant art installations and anthropological fieldwork, this paper reflects on some of our interactions with the kinds of machines we seem ready

Alex S. Taylor

2009-01-01

203

Woodworking Machines.  

National Technical Information Service (NTIS)

Woodworking machines are made to do a wide variety of jobs. For any one job there are usually a number of makes, sizes, and styles of machines from which to choose. They are not standardized. Only a brief classification and outline of specifications for f...

1964-01-01

204

Excavating machines  

SciTech Connect

The excavating machine has a cutter carrying boom carried by a boom support member which can be swung about an axis extending in the direction of the roadway. The machine includes a cutter unit and a stay unit each of which is releasably anchorable in the roadway and each of which can be advanced relative to the other unit.

Plummer, D.

1980-10-21

205

Machine Learning.  

ERIC Educational Resources Information Center

|As scientists seek to develop machines that can "learn," that is, solve problems by imitating the human brain, a gold mine of information on the processes of human learning is being discovered, expert systems are being improved, and human-machine interactions are being enhanced. (SK)|

Kirrane, Diane E.

1990-01-01

206

Electron emitting filaments for electron discharge devices  

DOEpatents

Electrons are copiously emitted by a device comprising a loop-shaped filament made of lanthanum hexaboride. The filament is directly heated by an electrical current produced along the filament by a power supply connected to the terminal legs of the filament. To produce a filament, a diamond saw or the like is used to cut a slice from a bar made of lanthanum hexaboride. The diamond saw is then used to cut the slice into the shape of a loop which may be generally rectangular, U-shaped, hairpin-shaped, zigzag-shaped, or generally circular. The filaments provide high electron emission at a relatively low operating temperature, such as 1600.degree. C. To achieve uniform heating, the filament is formed with a cross section which is tapered between the opposite ends of the filament to compensate for non-uniform current distribution along the filament due to the emission of electrons from the filament.

Leung, Ka-Ngo (Hercules, CA); Pincosy, Philip A. (Oakland, CA); Ehlers, Kenneth W. (Alamo, CA)

1988-01-01

207

Electron emitting filaments for electron discharge devices  

DOEpatents

Electrons are copiously emitted by a device comprising a loop-shaped filament made of lanthanum hexaboride. The filament is directly heated by an electrical current produced along the filament by a power supply connected to the terminal legs of the filament. To produce a filament, a diamond saw or the like is used to cut a slice from a bar made of lanthanum hexaboride. The diamond saw is then used to cut the slice into the shape of a loop which may be generally rectangular, U-shaped, hairpin-shaped, zigzag-shaped, or generally circular. The filaments provide high electron emission at a relatively low operating temperature, such as 1600/sup 0/C. To achieve uniform heating, the filament is formed with a cross section which is tapered between the opposite ends of the filament to compensate for nonuniform current distribution along the filament due to the emission of electrons from the filament.

Leung, K.N.; Pincosy, P.A.; Ehlers, K.W.

1983-06-10

208

Calculating machines  

NSDL National Science Digital Library

This website created by Erez Kaplan "deals mainly with the mechanical calculating machines from a collector's point of view." Included here is an historical review of calculating machines, along with Kaplan's attempt to classify the machines, a collection of old advertisements for the machines, and a brief history of calculating. The latest feature is a Java applet that lets you operate an 1885 Felt adding machine to give you a sense of the way it was used. The photos and descriptions provide insight on other gadgets such as the Pocket Cash Registers used by "the sophisticated man or woman of 1900 who had everything." The Reference section provides some resources for further reading, including numerous other personal calculator collectors sites and museums.

209

Rotating electric machine with fluid supported parts  

DOEpatents

A rotating electric machine in which the armature winding thereof and other parts are supported by a liquid to withstand the mechanical stresses applied during transient overloads and the like. In particular, a narrow gap is provided between the armature winding and the stator which supports it and this gap is filled with an externally pressurized viscous liquid. The liquid is externally pressurized sufficiently to balance the static loads on the armature winding. Transient mechanical loads which deform the armature winding alter the gap dimensions and thereby additionally pressurize the viscous liquid to oppose the armature winding deformation and more nearly uniformly to distribute the resulting mechanical stresses.

Smith, Jr., Joseph L. (Concord, MA); Kirtley, Jr., James L. (Brookline, MA)

1981-01-01

210

Comparative study of the behavior of wind-turbines in a wind farm  

Microsoft Academic Search

The Sotavento wind farm is an experimental wind farm which has different types of wind turbines. It is located in an area whose topography is moderately complex, and where wake effects can be significant. One of the objectives of Sotavento wind farm is to compare the performances of the different machines; particularly regarding power production, maintenance and failures. However, because

Emilio Migoya; Antonio Crespo; Javier García; Fermín Moreno; Fernando Manuel; Ángel Jiménez; Alexandre Costa

2007-01-01

211

Rotor Losses Measurements in an Axial Flux Permanent Magnet Machine  

Microsoft Academic Search

MMF space harmonics and slot openings produce considerable rotor losses in permanent magnet (PM) machines, especially if fractional-slot windings are adopted. This paper aims to measure the rotor losses of a 12-slot 10-pole axial flux phase modulation machine. Both MMF space harmonics and slot open- ings are considered. The prototype is an axial flux machine with open slots, equipped with

Luigi Alberti; Emanuele Fornasiero; Nicola Bianchi; Silverio Bolognani

2011-01-01

212

Scribbling Machines  

NSDL National Science Digital Library

In this activity, learners explore electronics and motion by making a Scribbling Machine, a motorized contraption that moves in unusual ways and leaves a mark to trace its path. Itâs made from simple materials and is based on the idea of motion created by an offset motor. Try using harvested motors and switches from discarded toys and electronics to make your Scribbling Machine - this not only keeps costs down, but is a playful and inventive way to explore how everyday objects work. To take the activity further, you can also incorporate PicoCrickets to make your Scribbling Machine more intelligent and to explore computers.

Exploratorium

2013-01-30

213

Math Machines  

NSDL National Science Digital Library

The mission of the Math Machines organization is to "improve the quality of mathematical education, enhance the transfer of mathematical thinking into other classes, and increase students' ability to apply rigorous mathematics outside the classroom." Their website supports a National Science Foundation ATE grant-supported project designed to improve teaching in the areas of Mathematics, Science, and Technology at the high school and college levels. This improved learning results from using math, science, and technology principles to build and control various machines such as pointers and robots or "math machines", which are simple devices that provide an immediate, physical, dynamic expression to abstract mathematical equations. The website provides information links on Educational Theory, Classroom Activities, Project Workshops, Calculators & Programs, and Machine Construction Instructions for Building: Closed Circuits, Servo Motors, Controllers, Robot Boards and more. There is also contact information, an FAQ section, as well as upcoming events.

2010-05-18

214

Pipetting Machine.  

National Technical Information Service (NTIS)

The pipetting machine is for use in a laboratory of physiology for the handling of serums. The apparatus includes a syringe and a valve portion constituting a variable stroke positive displacement pump and components for selecting a predetermined stroke t...

C. R. Mencken

1965-01-01

215

Simple Machines  

NSDL National Science Digital Library

This series of three interactive, multimedia activities introduce and demonstrate the properties of six simple machines. Specifically, the lessons show how levers, pulleys, inclined planes, screws, wheels and axles, and wedges can reduce the amount of work done by humans. After learning about the characteristics of each classification, users can try to find the simple machines that make up a lawn mower. By inspecting the mower from different angles, several simple machines are revealed and must be identified. The final activity lets users test their knowledge of the mechanics of simple machines. Following a builder through each stage of constructing a tree house, users can apply equations to determine the mechanical advantage supplied by using the tools.

216

Enertech 2kW high-reliability wind system. Phase II. Fabrication and testing  

Microsoft Academic Search

A high-reliability wind machine rated for 2 kW in a 9 m\\/s wind has been developed. Activities are summarized that are centered on the fabrication and testing of prototypes of the wind machine. The test results verified that the wind machine met the power output specification and that the variable-pitch rotor effectively controlled the rotor speed for wind speeds up

J. A. Cordes; B. A. Johnson

1981-01-01

217

Beam profile analysis for the C{ampersand}MS B231 electron beam welding machines  

SciTech Connect

The electron beams produced by two different welders were examined using computer assisted tomographic (CT) analysis. The machines used are Hamilton Standard welders with 150 kV/50mA maximum. One machine uses a ribbon filament while the other uses a hairpin filament. The objective of this study was to characterize the beam power distribution on each machine to see if weld parameters could easily be transferred between machines. Beam focus, voltage, and current settings were pre-selected to duplicate the welding conditions used in LLNL program applications. The results show that the actual beam currents measured by Faraday cup are 5 to 10% higher for the first machine and 30% lower for the second. The CT analysis of the beam shapes shows that the hairpin filament welder produces an elliptical beam shape in the sharp focus condition that defocuses to a diamond shape. The ribbon filament welder produced less of an elliptical beam shape in the sharp focus condition, but when defocused, acquires an elliptical shape. CT analysis of the effects of defocus on the peak power density shows that the hairpin filament drops in peak power density much more quickly than the ribbon filament for a given amount of defocus. Furthermore, it was more difficult to find and repeat the sharp focus condition for the hairpin filament, particularly at higher beam currents.

Elmer, J. W.; Teruya, A.T.; Gauthier, M.

1997-06-12

218

Logistics Machining Data.  

National Technical Information Service (NTIS)

Contents: Machining operations; tool geometry; cutting fluids; electrical, chemical, special mechanical and optical machining processes; supplemental machining data and information; economics in machining; instructions in machining; surface finish; numeri...

1966-01-01

219

Coiling of a viscous filament  

NASA Astrophysics Data System (ADS)

A classic demonstration of fluid buckling is a daily occurence at the breakfast table, where a continuous stream of viscous fluid (honey) is often poured onto a flat surface (toast) from a sufficient height. The thin fluid filament quickly settles into a steady state; near the surface it bends into a helical shape while simultaneously rotating about the vertical and is laid out in a regular coil. This behavior is reminiscent of the coiling of a falling flexible rope. We derive a simple scaling law that predicts the coiling frequency in terms of the filament radius and the flow rate. We also verify this scaling law with the results of experiments.

Samuel, A. D. T.; Ryu, W. S.; Mahadevan, L.

1997-11-01

220

Virtual filaments that mimic conventional light bulb filaments  

Microsoft Academic Search

Conventional incandescent light bulbs have a wire filament acting as an extended light source with nearly constant intensity throughout its quasi-spherical emission pattern. Here we present a novel family of optical devices that make use of commercially available Lambertian or near-Lambertian LED light sources, in conjunction with tailored optical element bonded to the top surface of the LED. These hybrid

Julio Chaves; Fernando Muñoz; Juan Carlos Miñano; Pablo Benítez; Bill Parkyn; Waqidi Falicoff; Yupin Sun

2004-01-01

221

Wind turbine noise workshop. Proceedings.  

National Technical Information Service (NTIS)

Noise generated by wind turbines is an environmental constraint on the exploitation of wind energy. It is a major consideration when seeking planning consent for the siting of machines due to the high population density in the UK and low levels of backgro...

M. Legerton

1993-01-01

222

LOCALIZATION OF MYOSIN FILAMENTS IN SMOOTH MUSCLE  

PubMed Central

Thick myosin filaments, in addition to actin filaments, were found in sections of glycerinated chicken gizzard smooth muscle when fixed at a pH below 6.6. The thick filaments were often grouped into bundles and run in the longitudinal axis of the smooth muscle cell. Each thick filament was surrounded by a number of thin filaments, giving the filament arrangement a rosette appearance in cross-section. The exact ratio of thick filaments to thin filaments could not be determined since most arrays were not so regular as those commonly found in striated muscle. Some rosettes had seven or eight thin filaments surrounding a single thick filament. Homogenates of smooth muscle of chicken gizzard also showed both thick and thin filaments when the isolation was carried out at a pH below 6.6, but only thin filaments were found at pH 7.4. No Z or M lines were observed in chicken gizzard muscle containing both thick and thin filaments. The lack of these organizing structures may allow smooth muscle myosin to disaggregate readily at pH 7.4.

Kelly, Robert E.; Rice, Robert V.

1968-01-01

223

Design Considerations for Tubular Flux-Switching Permanent Magnet Machines  

Microsoft Academic Search

This paper describes a tubular, three-phase, flux-switching permanent magnet (PM) brushless machine that combines salient features from switched reluctance (SR) and conventional PM brushless machines. Feasible slot-pole number combinations, which are also applicable to rotary flux-switching machines, are derived. This paper also examines an alternative stator winding configuration, which is unique to the tubular machine topology. It is shown that

Jiabin Wang; Weiya Wang; Kais Atallah; David Howe

2008-01-01

224

Wind Conditions in Oversea Countries in View of Wind Power Utilization.  

National Technical Information Service (NTIS)

The rapid progress in design and construction of wind machines suggests a review of the possibilities of their adequate employment. As the utilization of wind power in developing countries claims more and more interest, the design of such machines and its...

G. Duensing G. Gruenewald V. Wagner G. Martens

1985-01-01

225

Evaluation of Broom Filaments for Powered Sweepers.  

National Technical Information Service (NTIS)

Tests were conducted to determine the most efficient and economical broom filament and brush construction for industrial and street sweepers. The tests included accelerated wear tests of various kinds of filament materials, sweeping efficiency tests of pi...

J. J. Bayles

1964-01-01

226

Solar Filament Eruption Creates 'Canyon of Fire'  

NASA Website

filament of solar material erupted on the sun in late September, breaking the quiet conditions in a spectacular fashion. The 200,000 mile long filament ripped through the sun's atmosphere, the corona, leaving behind what looks like a canyon ...

227

Huge Filament Rises From Sun's Northern Hemisphere  

NASA Video Gallery

On August 1, 2010 following a C3-class solar flare from sunspot 1092, an enormous magnetic filament stretching across the sun's northern hemisphere erupted. This 304 angstrom video shows that filament and was taken by NASA's Solar Dynamics Observatory.

Holly Zell

2010-11-15

228

Intermediate filaments mediate cytoskeletal crosstalk  

Microsoft Academic Search

Intermediate filaments, actin-containing microfilaments and microtubules are the three main cytoskeletal systems of vertebrate and many invertebrate cells. Although these systems are composed of distinctly different proteins, they are in constant and intimate communication with one another. Understanding the molecular basis of this cytoskeletal crosstalk is essential for determining the mechanisms that underlie many cell-biological phenomena. Recent studies have revealed

Lynne Chang; Robert D. Goldman

2004-01-01

229

Theory of crosslinked bundles of helical filaments: Intrinsic torques in self-limiting biopolymer assemblies  

NASA Astrophysics Data System (ADS)

Inspired by the complex influence of the globular crosslinking proteins on the formation of biofilament bundles in living organisms, we study and analyze a theoretical model for the structure and thermodynamics of bundles of helical filaments assembled in the presence of crosslinking molecules. The helical structure of filaments, a universal feature of biopolymers such as filamentous actin, is shown to generically frustrate the geometry of crosslinking between the ``grooves'' of two neighboring filaments. We develop a coarse-grained model to investigate the interplay between the geometry of binding and mechanics of both linker and filament distortion, and we show that crosslinking in parallel bundles of helical filaments generates intrinsic torques, of the type that tend to wind the bundle superhelically about its central axis. Crosslinking mediates a non-linear competition between the preference for bundle twist and the size-dependent mechanical cost of filament bending, which in turn gives rise to feedback between the global twist of self-assembled bundles and their lateral size. Finally, we demonstrate that above a critical density of bound crosslinkers, twisted bundles form with a thermodynamically preferred radius that, in turn, increases with a further increase in crosslinking bonds. We identify the stiffness of crosslinking bonds as a key parameter governing the sensitivity of bundle structure and assembly to the availability and affinity of crosslinkers.

Heussinger, Claus; Grason, Gregory M.

2011-07-01

230

Generation of the Cape Ghir upwelling filament: A numerical study  

NASA Astrophysics Data System (ADS)

Filaments are narrow, shallow structures of cool water originating from the coast. They are typical features of the four main eastern boundary upwelling systems (EBUS). In spite of their significant biological and chemical roles, through the offshore exportation of nutrient-rich waters, the physical processes that generate them are still not completely understood. This paper is a process-oriented study of filament generation mechanisms. Our goal is twofold: firstly, to obtain a numerical solution able to correctly represent the characteristics of the filament off Cape Ghir (30°38?N, northwest Africa) in the Canary EBUS and secondly, to explain its formation by a simple mechanism based on the balance of potential vorticity.The first goal is achieved by the use of the ROMS model (Regional Ocean Modeling System) with embedded domains around Cape Ghir, with a horizontal resolution going up to 1.5 km for the finest domain. The latter gets its initial and boundary conditions from a parent solution and is forced by climatological, high-resolution atmospheric fields. The modeled filaments display spatial, temporal and physical characteristics in agreement with the available in situ and satellite observations. This model solution is used as a reference to compare the results with a set of process-oriented experiments. These experiments allow us to reach the second objective. The solutions serve to highlight the contributions of various processes on the filament generation. Since the study is focused on general processes present under climatological forcing conditions, inter-annual forcing is not necessary.The underlying idea for the filament generation is the balance of potential vorticity in the Canary EBUS: the upwelling jet is characterized by negative relative vorticity and flows southward along a narrow band of uniform potential vorticity. In the vicinity of the cape, an injection of relative vorticity induced by the wind breaks the existing vorticity balance. The upwelling jet is prevented from continuing its way southward and has to turn offshore to follow lines of equal potential vorticity.The model results highlight the essential role of wind, associated with the particular topography (coastline and bottom) around the cape. The mechanism presented here is general and thus can be applied to other EBUS.

Troupin, Charles; Mason, Evan; Beckers, Jean-Marie; Sangrà, Pablo

231

Development, persistence and variability of upwelling filaments off the Atlantic coast of the Iberian Peninsula  

Microsoft Academic Search

The development, persistence, and variability of upwelling filaments off the Atlantic coast of the Iberian Peninsula are examined by means of advanced very high resolution radiometer infrared imagery observed between 1982 and 1990. These observations indicate that the regime is broadly similar to that observed in the California Current system and is closely related to the large scale wind climatology

R. Haynes; E. D. Barton; I. Pilling

1993-01-01

232

A biodegradable filament for controlled drug delivery  

Microsoft Academic Search

Biodegradable filaments (diameters of 250–300 ?m) for the controlled delivery of dexamethasone or levofloxacin are described. Filaments are prepared by wet-spinning solutions of poly(lactide-co-glycolide) (PLGA) and drug dissolved in dimethyl sulfoxide (DMSO) into a coagulation bath of water. Compositional analyses of the filaments by independent measurements of drug, DMSO, water, and polymer give drug loadings up to 40% of filament mass

Brendan C. Mack; Kenneth W. Wright; Mark E. Davis

2009-01-01

233

Degradation and silicidation of Ta and W-filaments for different filament temperatures  

Microsoft Academic Search

Using typical conditions for hot wire chemical vapour deposition (HWCVD) of high quality thin silicon films in a UHV deposition chamber, we studied the silicidation of different filaments mainly varying the filament temperatures between 1700 °C and 2130 °C. The experiments were done with constant current, running the filament for 5 to 8 h and even longer. The changes of filament resistance and

N. Kniffler; A. Pflueger; D. Scheller; B. Schroeder

2009-01-01

234

Culture Machine  

NSDL National Science Digital Library

Culture Machine is a new, refereed, electronic journal encompassing cultural studies and cultural theory. The international editorial board of the interactive journal aims to "generat[e] research in culture and theory" by promoting and publishing "the most provocative of new work." The theme of the inaugural issue is Taking Risks with the Future. Content includes articles such as Life After Death of the Text by Johan Fornas, Cultural Studies in the Clouds: Mourning for Detail by Tadeusz Slawek, and The Future States of Politics by Kenneth Surin. Culture Machine is hosted by the University of Teesside, England.

235

Membrane Buckling Induced by Curved Filaments  

Microsoft Academic Search

We present a novel buckling instability relevant to membrane budding in eukaryotic cells. In this mechanism, curved filaments bind to a lipid bilayer without changing its intrinsic curvature. As more and more filaments adsorb, newly added ones are more and more strained, which destabilizes the flat membrane. We perform a linear stability analysis of filament-dressed membranes and find that the

Martin Lenz; Daniel J. G. Crow; Jean-François Joanny

2009-01-01

236

Production of high bulk polyester filament yarn  

Microsoft Academic Search

This paper reports a method for producing high bulk polyethylene terephthalate (PET) filament yarns composed of shrink and nonshrink filament yarns. Normally, high bulk yarns are mainly made out of shrink and nonshrink staple fibers especially polyacrylonitrile through semi-worsted spinning process. The method described in this paper involves blending two PET filament yarns, one acting as shrink component and the

H. Tavanai; M. Morshed; A. Moghaddam

2012-01-01

237

Helical waves on a vortex filament  

NASA Astrophysics Data System (ADS)

A vortex filament in a perfect fluid is an excellent system, similar to an elastic string, elastic membrane, diffusion tube, and conducting rod, for presenting the equations of mathematical physics. A small amplitude helical wave spreading along an unstretchable vortex filament is shown to obey the linear Schrödinger equation. Taking into account elastic properties of the filament leads to the Klein-Gordon equation.

Dmitriyev, Valery P.

2005-06-01

238

Wind turbine rotor  

Microsoft Academic Search

A fixed pitch wind turbine rotor is teeter mounted onto a low speed input shaft which is connected to the input of a step-up transmission. The output of the transmission is connected to a rotary pole amplitude modulated induction machine which is operable as a generator at a plurality of discreet speeds of rotation and is also operable as a

J. M. Baskin; G. E. Miller; W. Wiesner

1985-01-01

239

Composite rotor blades for wind turbine generators  

Microsoft Academic Search

The materials, techniques, and methods used to construct a 150 ft test blade, two 31 ft blades for a 40 kW WECS, and rotor blades for the Mod-1 wind turbine are described. Considerations of strength, stiffness, and mass distributions, as well as cost, led to the choice of filament wound fiberglass\\/epoxy material using transverse filament tape which has structural fibers

W. D. Weigel

1981-01-01

240

The Geography of Wind Energy: Problem Solving Activities.  

ERIC Educational Resources Information Center

|Today there are many attempts to use wind machines to confront the increasing costs of electricity. Described are activities to help secondary students understand wind energy, its distribution, applications, and limitations. (RM)|

Lahart, David E.; Allen, Rodney F.

1985-01-01

241

Temporal symmetry of individual filaments in different spatial symmetry filaments pattern in a dielectric barrier discharge  

SciTech Connect

The temporal behavior of individual filament in different spatial symmetry filaments patterns in dielectric barrier discharge is investigated by using an optical method. A series of return maps of the discharge moments of individual filaments is given. It is found that the temporal symmetry of individual filament changes with the change of the spatial symmetry of filaments pattern as the applied voltage increases. The role of wall charges for this phenomenon is analyzed.

Dong, L. F.; Xiao, H.; Fan, W. L.; Yin, Z. Q.; Zhao, H. T. [College of Physics Science and Technology, Hebei University, Baoding 071002 (China)

2010-10-15

242

Leonardo's Machines  

NSDL National Science Digital Library

This Science NetLinks lesson will highlight some of Leonardo da Vinci's futuristic inventions, introducing the elements of machines. Through the use of student interactives, this lesson provides an interesting context in which students can begin to develop their ideas about the uniqueness of humans in the natural world.

Science Netlinks;

2003-03-05

243

Function Machine  

NSDL National Science Digital Library

This Java applet allows learners to explore simple linear functions. Students determine the algebraic form of a linear equation by entering inputs into the machine and by looking for patterns in the outputs. The function rules available are: integers from -10 to 10 are either added to, subtracted from, or multiplied by the input x to yield the output y.

2011-01-01

244

Mining machine  

Microsoft Academic Search

A mining machine is disclosed in which a cutting drum undercuts a vein of coal and side relief cutters make vertical kerfs in the vein upwardly from the undercut. A chisel plate is forced into the coal vein and breaks loose the material above the undercut and between the side relief cuts. The coal falls into conveyors and is loaded

Mendola

1981-01-01

245

Decoding Machine  

NSDL National Science Digital Library

In this math lesson, learners explore variables and their uses. Learners pretend to be FBI agents and make a TOP SECRET tool that enables them to decode and find the values of hidden messages and words. Learners make their simple "decoding machines" out of paper and tape.

Lessonplans, Utah

2012-10-22

246

Laugh Machine  

Microsoft Academic Search

The Laugh Machine project aims at endowing virtual agents with the capability to laugh naturally, at the right moment and with the correct intensity, when interacting with human participants. In this report we present the technical development and evaluation of such an agent in one specific scenario: watching TV along with a participant. The agent must be able to react

Jrme Urbain; Radoslaw Niewiadomski; Jennifer Hofmann; Emeline Bantegnie; Tobias Baur; Nadia Berthouze; Hseyin Cakmak; Richard Thomas Cruz; Stphane Dupont; Matthieu Geist; Harry Griffin; Florian Lingenfelser; Maurizio Mancini; Miguel Miranda; Gary McKeown; Sathish Pammi; Olivier Pietquin; Bilal Piot; Tracey Platt; Willibald Ruch; Abhishek Sharma; Gualtiero Volpe; Johannes Wagner

2012-01-01

247

Wacky Machines  

ERIC Educational Resources Information Center

Collectors everywhere know that local antique shops and flea markets are treasure troves just waiting to be plundered. Science teachers might take a hint from these hobbyists, for the next community yard sale might be a repository of old, quirky items that are just the things to get students thinking about simple machines. By introducing some…

Fendrich, Jean

2002-01-01

248

Addition Machines.  

National Technical Information Service (NTIS)

An addition machine is a computing device with a finite number of registers, limited to the following six types of operations: input to register x; copy register y to register x; add register y to register x; subtract register y from register x; compare r...

R. W. Floyd D. E. Knuth

1989-01-01

249

A biodegradable filament for controlled drug delivery.  

PubMed

Biodegradable filaments (diameters of 250-300 microm) for the controlled delivery of dexamethasone or levofloxacin are described. Filaments are prepared by wet-spinning solutions of poly(lactide-co-glycolide) (PLGA) and drug dissolved in dimethyl sulfoxide (DMSO) into a coagulation bath of water. Compositional analyses of the filaments by independent measurements of drug, DMSO, water, and polymer give drug loadings up to 40% of filament mass and drug retention (drug in filament per drug in solution) greater than 40%. Drug release kinetics, and thermal and mechanical properties, of the filaments are reported. Three filaments with levofloxacin contents of 46+/-2, 85+/-4, and 36+/-2 microg/cm (denoted 506-L1, 506-L2, and 506-L3, respectively) are implanted in the conjunctiva of New Zealand white rabbits. The time dependent, in-vivo tear concentrations of levofloxacin from filament implants in New Zealand white rabbit eyes are in general agreement with the results from the in-vitro release profiles, with one of the filaments (506-L1) showing effective levels of levofloxacin in the tears for 6 days. The filaments are generally well tolerated by the rabbits. Filament failure occurs at 6-8 days within the rabbit eyes, essentially the same time to failure observed from in-vitro mechanical properties testing results. PMID:19567255

Mack, Brendan C; Wright, Kenneth W; Davis, Mark E

2009-06-28

250

Fluctuating elastic filaments under distributed loads.  

PubMed

Filaments under distributed loads are common in biological systems. In this paper, we study the thermo-mechanical properties of an extensible thermally fluctuating elastic filament under distributed forces. The ground state of the filament is solved first, followed by an investigation of the thermal fluctuations around the ground state. We first consider a special case where the tangential component of the distributed force tau is uniform along the filament. For the force-extension relation in this case, we show that the filament is equivalent to one under end-to-end applied force F = tauL0/2 where L0 is the length of the filament. To study the thermal fluctuations under more general distributed loadings, the filament is first discretized into segments, and its energy is approximated up to quadratic order. Then the partition function of the discretized filament, or chain, is evaluated using multi-dimensional Gaussian integrals, from which free energy and other properties of the filament are derived. We show that a filament under distributed loads suffers larger thermal fluctuations than one with the end loads of the same magnitude. We also show that our results for a discretized filament agree with continuum theory for a continuous rod. Finally, we give some applications of our ideas to the stretching and fluctuation of DNA in non-uniform microfluidic channels. PMID:21977517

Su, Tianxiang; Purohit, Prashant K

2011-09-01

251

Partial Slingshot Reconnection between Two Filaments  

NASA Astrophysics Data System (ADS)

We present a rare observation of an interaction between two filaments around AR 11358 and AR 11361 on 2011 December 3 that is strongly suggestive of the occurrence of slingshot reconnection. A small elbow-shaped active-region filament (F12) underwent a failed eruption that brought it into contact with a nearby larger, thicker filament (F34). Accompanied by the appearance of complicated internal structures below the erupting F12, its two legs separated away from each other and then connected into F34. This process led the filaments to change their connectivity to form two newly linked filaments, and one of them showed a clear inverse ?-shape. However, the alteration in the filament connectivity was imperfect since F34 is discernible after the eruption. These observations can be interpreted as a partial slingshot reconnection between two filaments that had unequal axial magnetic flux.

Jiang, Yunchun; Hong, Junchao; Yang, Jiayan; Bi, Yi; Zheng, Ruisheng; Yang, Bo; Li, Haidong; Yang, Dan

2013-02-01

252

Reliability of wind power from dispersed sites: A preliminary assessment  

Microsoft Academic Search

The reliability benefit of geographically dispersed wind turbine generators is analyzed. Electricity produced from wind machines experienced wide fluctuations of output at a given site. The conventional wisdom on wind power suggested that it is unrealistic to expect that wind generation will be sufficiently reliable to displace conventional capacity. Bibtex entry for this abstract Preferred format for this abstract (see

E. Kahn

1978-01-01

253

Mechanism of caveolin filament assembly  

Microsoft Academic Search

Caveolin-1 was the first protein identified that colocalizes with the 10-nm filaments found on the inside surface of caveolae membranes. We have used a combination of electron microscopy (EM), circular dichroism, and analytical ultracentrifugation to determine the structure of the oligomers that form when the first 101 aa of caveolin-1 (Cav1-101) are allowed to associate. We determined that amino acids

Imma Fernandez; Yunshu Ying; Joseph Albanesi; Richard G. W. Anderson

2002-01-01

254

Drilling Machines: Vocational Machine Shop.  

ERIC Educational Resources Information Center

|The lessons and supportive information in this field tested instructional block provide a guide for teachers in developing a machine shop course of study in drilling. The document is comprised of operation sheets, information sheets, and transparency masters for 23 lessons. Each lesson plan includes a performance objective, material and tools,…

Thomas, John C.

255

An Unusual System of H I Filaments near WR 5 and HD 17603  

NASA Astrophysics Data System (ADS)

We report the discovery of a system of unusual H I filaments that appear to be associated with molecular clouds in the Perseus spiral arm of our Galaxy. We investigate the hypothesis that this system is the result of a directed flow of dissociated gas from clouds trapped within an extended wind flow from massive stars. The Wolf-Rayet star WR 5 and the O Ib(f) star HD 17603 are identified as candidate driving sources. However, an examination of this hypothesis within the context of the theory of mass-loaded winds shows that these two stars alone cannot account for the energetics and kinematics of the required spherically symmetric wind flow. Unless the apparent association between H I, molecular gas, and stars is an accidental one, we suggest that other as yet unidentified stars must have contributed to driving the filaments.

Knee, Lewis B. G.; Wallace, Bradley J.; Normandeau, Magdalen

2005-08-01

256

Simple Machines  

NSDL National Science Digital Library

The goals for this introduction activity to Simple Machines are.: - Generate scientific questions about the world based on observation - Design and conduct scientific investigations - Use tools and equipment appropriate to scientific investigations - Use sources of information in support of scientific investigation - Write and follow procedures in the form of step-by-step instructions, formulas, flow diagram, and sketches - Show how common themes of science, mathematics, and technology apply in real-world contexts - Recognize the contributions made in science by cultures and individuals of diverse backgrounds - Design strategies for moving objects by application of forces, including the use of simple machines MERC Online Reviewer Comments: Good computer activities for under-represented students who want to pursue manufacturing education. Distance Learning is a plus.

Wakild, Terri

2009-11-30

257

Charging machine  

DOEpatents

A charging machine for loading fuel slugs into the process tubes of a nuclear reactor includes a tubular housing connected to the process tube, a charging trough connected to the other end of the tubular housing, a device for loading the charging trough with a group of fuel slugs, means for equalizing the coolant pressure in the charging trough with the pressure in the process tubes, means for pushing the group of fuel slugs into the process tube and a latch and a seal engaging the last object in the group of fuel slugs to prevent the fuel slugs from being ejected from the process tube when the pusher is removed and to prevent pressure liquid from entering the charging machine.

Medlin, John B. (Newark, DE)

1976-05-25

258

Interplanetary shocks preceded by solar-filament eruptions  

SciTech Connect

Solar and interplanetary characteristics of six interplanetary shock and energetic particle events associated with the eruptions of solar filaments lying outside active regions are discussed. The events are characterized by the familiar double-ribbon Hx brightenings observed with large flares, but only very-weak soft x-ray and microwave bursts. Both impulsive phases and metric type-II bursts are absent in all six events. The energetic particles observed near the earth appear to be accelerated predominantly in the interplanetary shocks. The interplanetary shock speeds are lower and the longitudinal extents considerably less than those of flare-associated shocks. Three of the events were associated with unusual enhancements of singly ionized helium in the solar wind following the shocks. These enhancements appear to be direct detections of the cool filaments material expelled from the corona. It is suggested that these events are part of a spectrum of solar-eruptive events which include both weaker events and large flares. Despite their unimpressive and unreported solar signatures, the quiescent filament eruptions can result in substantial space and geophysical disturbances.

Cane, H.V.; Kahler, S.W.; Sheeley, N.R.

1986-12-01

259

Voting machine  

US Patent & Trademark Office Database

A compact, versatile voting machine is disclosed having adaptability for use with various vote registering devices such as tally counters and punch card apparatus. The voting machine includes a selector mechanism having a series of parallel columns housing voter operated key slides. A vertical interlock mechanism includes ball housing blocks which are alternately disposed between the key slides and house displaceable interlock balls in a tool line. The cam blocks are adjustable to limit the effective length of the tool line to establish groupings of candidates from which a single selection can be made. A magazine at the top of each column is adjustable to permit multiple selections from a grouping. Actuation of a key cams the interlock balls into the tool line, and when a predetermined number of voter selections have been made no additional keys can be actuated as they are blocked by the tool line. A row of adjacent horizontal keys can also be interlocked to established selection groups as typically found on a general election ballot. A bar is moveable to horizontally interlock adjacent columns by introducing locking pins into a position to be cammed by actuation of a key. A drive mechanism associated with each column permits the voter to vote straight party and clears the machine to ready it for another voter. The drive mechanism includes cam controlled clutches that operate four-bar linkage elements to depress or return the key slides. A judge controlled mechanism locks the machine between voters. For various voting requirements, judge operated cam arrangements are cooperable with the horizontal locking pins and the four-bar linkage to selectively lock out partial or entire columns or rows of key slides. The key slides are provided with a voter viewable button that registers a visible, luminescent X when a key is voted.

O'Neal; Cothburn M. (Dallas, TX); Mayo; Alfred M. (Richardson, TX); Childs, deceased; George William (LATE OF DTX, TX)

1976-01-27

260

Statistical analysis of wind characteristics at candidate wind-turbine sites  

Microsoft Academic Search

Accurate prediction for a wind turbine facility performance is dependent on appropriate wind characteristics data. This report presents preliminary recommendations of appropriate data recording procedures for initial site evaluation and for large machine performance evaluation. Conclusions are based on autocorrelation, autospectrum persistence, cross-correlation, and coherence analysis of a limited sample of wind speed and turbine power data collected at the

Corotis

1982-01-01

261

Application of Gaussian Process to wind speed forecasting for wind power generation  

Microsoft Academic Search

This paper proposes a new kernel machine method for short-term wind speed forecasting. Renewable energy is attractive to protect environment. As renewable energy, wind power generation, solar energy generation, geothermal energy generation, etc. are spread in the world. In Japan, wind power generation is of main concern due to the execution of the Renewable Portfolio Standard (RPS). However, it is

Hiroyuki Mori; Eitaro Kurata

2008-01-01

262

Machine vision  

SciTech Connect

To keep up with the speeds of modern production lines, most machine vision applications require very powerful computers (often parallel-processing machines), which process millions of points of data in real time. The human brain performs approximately 100 billion logical floating-point operations each second. That is 400 times the speed of a Cray-1 supercomputer. The right software must be developed for parallel-processing computers. The NSF has awarded Rensselaer Polytechnic Institute (Troy, N.Y.) a $2 million grant for parallel- and image-processing software research. Over the last 15 years, Rensselaer has been conducting image-processing research, including work with high-definition TV (HDTV) and image coding and understanding. A similar NSF grant has been awarded to Michigan State University (East Lansing, Mich.) Neural networks are supposed to emulate human learning patterns. These networks and their hardware implementations (neurocomputers) show a great deal of promise for machine vision systems because they allow the systems to understand the use sensory data input more effectively. Neurocomputers excel at pattern-recognition tasks when input data are fuzzy or the vision algorithm is not optimal and is difficult to ascertain.

Horn, D.

1989-06-01

263

Actin filament curvature biases branching direction  

NASA Astrophysics Data System (ADS)

Actin filaments are key components of the cellular machinery, vital for a wide range of processes ranging from cell motility to endocytosis. Actin filaments can branch, and essential in this process is a protein complex known as the Arp2/3 complex, which nucleate new ``daughter'' filaments from pre-existing ``mother'' filaments by attaching itself to the mother filament. Though much progress has been made in understanding the Arp2/3-actin junction, some very interesting questions remain. In particular, F-actin is a dynamic polymer that undergoes a wide range of fluctuations. Prior studies of the Arp2/3-actin junction provides a very static notion of Arp2/3 binding. The question we ask is how differently does the Arp2/3 complex interact with a straight filament compared to a bent filament? In this study, we used Monte Carlo simulations of a surface-tethered worm-like chain to explore possible mechanisms underlying the experimental observation that there exists preferential branch formation by the Arp2/3 complex on the convex face of a curved filament. We show that a fluctuation gating model in which Arp2/3 binding to the actin filament is dependent upon a rare high-local-curvature shape fluctuation of the filament is consistent with the experimental data.

Wang, Evan; Risca, Viviana; Chaudhuri, Ovijit; Chia, Jia-Jun; Geissler, Phillip; Fletcher, Daniel

2012-02-01

264

Hydrophobic loop dynamics and actin filament stability.  

PubMed

It has been postulated that the hydrophobic loop of actin (residues 262-274) swings out and inserts into the opposite strand in the filament, stabilizing the filament structure. Here, we analyzed the hydrophobic loop dynamics utilizing four mutants that have cysteine residues introduced at a single location along the yeast actin loop. Lateral, copper-catalyzed disulfide cross-linking of the mutant cysteine residues to the native C374 in the neighboring strand within the filament was fastest for S265C, followed by V266C, L267C, and then L269C. Site-directed spin labeling (SDSL) studies revealed that C265 lies closest to C374 within the filament, followed by C266, C267, and then C269. These results are not predicted by the Holmes extended loop model of F-actin. Furthermore, we find that disulfide cross-linking destroys L267C and L269C filaments; only small filaments are observed via electron microscopy. Conversely, phalloidin protects the L267C and L269C filaments and inhibits their disulfide cross-linking. Combined, our data indicate that, in solution, the loop resides predominantly in a "parked" position within the filament but is able to dynamically populate other conformational states which stabilize or destabilize the filament. Such states may be exploited within a cell by filament-stabilizing and -destabilizing factors. PMID:17087511

Scoville, Damon; Stamm, John D; Toledo-Warshaviak, Dora; Altenbach, Christian; Phillips, Martin; Shvetsov, Alexander; Rubenstein, Peter A; Hubbell, Wayne L; Reisler, Emil

2006-11-14

265

Modeling and Real-Time Simulation of Internal Faults in Synchronous Generators With Parallel-Connected Windings  

Microsoft Academic Search

In large synchronous generators, the stator windings are usually parallel-connected in order to increase the machine current capacity. In analysis and modeling, the parallel windings are usually lumped into one equivalent stator winding since equal currents flow in these windings. However, when an internal fault occurs in the windings, the symmetry between the parallel windings is broken and different currents

Xiaoping Tu; Louis-A. Dessaint; Nicolas Fallati; Bruno De Kelper

2007-01-01

266

A Case of Filament - Active Region Interaction  

NASA Astrophysics Data System (ADS)

We analyze a huge filament observed between 5 and 19 September 2001. In its evolution it is linked to the active region 9612, observed between 7 and 16 September 2001. The filament has a strange morphology and dynamics: starting as two parallel components (A and B), it becomes a double sigmoid filament when a third component (C ) appears linking the other two. An unusual magnetic topology characterizes this evolution: the active region is located between the parallel components. When the third component becomes observable, it links these ones first below the active region. After a spectacular plasma movement registered in filament (A), this one becomes linked to (B) above the active region. In spite of these dramatically changes of the magnetic topology and filament -- active region switch, no CME is observed. Only a few flares occurring in AR9612 are registered and these ones can be seen in the dynamics of the filament as an expression of large scale magnetic reconnections.

Dumitrache, C.; Dumitru, L.

2010-09-01

267

[Morphogenesis in a community of filamentous cyanobacteria].  

PubMed

Reversible differentiation was experimentally discovered in a community of modern filamentous cyanobacteria Oscillatoria terebriformis. Splitting of the initially uniform community into differentiated parts (strands, multiradiate aggregates, networks, etc.) occurs only for the duration of a function facilitating the activity of this community as an integral unit. The structures are formed as a result of regrouping of the filaments, without their specialization. A morphologically regulatory system (polygonal network) was found to develop under the impact of extreme factors. The levels of structural organization of filamentous cyanobacteria and multicellular eukaryotes were compared (individual cells in a filament--cell organelles; filaments--individual cells; community--organism), and the similarities and differences in morphogenesis of these groups were analyzed using the data on the embryonic regulation in multicellular eukaryotes. Spatial information in morphogenesis was shown to result not from direct realization of an inherited program but is created by the elements of integral organisms (cells and filaments) in the course of development. PMID:23885567

Sumina, E L; Sumin, D L

268

Plasticity of Intermediate Filament Subunits  

PubMed Central

Intermediate filaments (IFs) assembled in vitro from recombinantly expressed proteins have a diameter of 8–12 nm and can reach several micrometers in length. IFs assemble from a soluble pool of subunits, tetramers in the case of vimentin. Upon salt addition, the subunits form first unit length filaments (ULFs) within seconds and then assembly proceeds further by end-to-end fusion of ULFs and short filaments. So far, IF subunits have mainly been observed by electron microscopy of glycerol sprayed and rotary metal shadowed specimens. Due to the shear forces during spraying the IF subunits appear generally as straight thin rods. In this study, we used atomic force microscopy (AFM), cryo-electron microscopy (cryo-EM) combined with molecular modeling to investigate the conformation of the subunits of vimentin, desmin and keratin K5/K14 IFs in various conditions. Due to their anisotropic shape the subunits are difficult to image at high resolution by cryo-EM. In order to enhance contrast we used a cryo-negative staining approach. The subunits were clearly identified as thin, slightly curved rods. However the staining agent also forced the subunits to aggregate into two-dimensional networks of dot-like structures. To test this conformational change further, we imaged dried unfixed subunits on mica by AFM revealing a mixture of extended and dot-like conformations. The use of divalent ions such as calcium and magnesium, as well as glutaraldehyde exposure favored compact conformations over elongated ones. These experimental results as well as coarse-grained molecular dynamics simulations of a vimentin tetramer highlight the plasticity of IF subunits.

Hoenger, Andrea; Buehler, Markus J.; Kreplak, Laurent

2010-01-01

269

Machine Design  

NSDL National Science Digital Library

This website, the homepage of Machine Design.com, contains resources on a variety of information for engineers and technicians related to devices, components, design applications, products, and systems in the manufacturing technology sector. The site also features a CAD library, eBooks, audiovisual aids, webinars, whitepapers and a reference center. Some of the resources require a free login. The page offers an RSS feed to keep users up to date on new resources. A free login may be required to access some of these items.

2009-11-09

270

Studies on UV filaments in air  

SciTech Connect

UV filaments in air have been examined on the basis of the diameter and length of the filament, the generation of new spectral components, and the ionization by multiphoton processes. There have been numerous observations of filaments at 800 nm. The general perception is that, above a critical power, the beam focuses because nonlinear self-lensing overcomes diffraction. The self-focusing proceeds until an opposing higher order nonlinearity forms a stable balance.

Schwarz, J.; Rambo, P.; Diels, J.C.; Luk, T.S.; Bernstein, A.C.; Cameron, S.M.

2000-01-05

271

Plasma waveguide array induced by filament interaction.  

PubMed

We demonstrate that interference-assisted coalescence of two noncollinearly overlapped filaments creates a wavelength-scale periodic plasma density modulation to guide the input pulses equivalently as a photonic crystal plasma waveguide. The periodic self-channeling is evidenced by the direct observation of the filament coalescence, which reveals wavelength-scale spatial widths and periodicity dependent on the crossing angles and intensity ratios between the incident filaments. PMID:20016620

Yang, Xuan; Wu, Jian; Peng, Yan; Tong, Yuqi; Lu, Peifen; Ding, Liang'en; Xu, Zhizhan; Zeng, Heping

2009-12-15

272

[Polar filaments of Myxobolus pseudodispar spores].  

PubMed

Spores of Myxobolus pseudodispar from plasmodia occurring in the roach muscles (Rutilus rutilus) were studied by light, transmission and scanning electron microscopy, before and after discharge of their polar filaments. Scanning microscopy reveals that discharged polar filaments bear no spines and their walls are slightly folded. Polar filaments of M. pseudodispar have been compared with stinging threads of the parasitic cnidarium Polypodium hydriforme. PMID:11601388

Ibragimov, A Iu

2001-01-01

273

Niobium-titanium superconducting wires with ultrafine filaments (A role of SC filament-matrix boundaries)  

Microsoft Academic Search

The current carrying capacity and the magnetic hysteresis curve of ultrafine filaments wires are determined by the fluxoid pinning on Nb-Ti filament-matrix boundaries. The pinning is reduced by interdiffusion of Cu and Ti.

G. L. Dorofejev; S. V. Frolov; E. Y. Klimenko; V. Y. Filkin; E. V. Nikuenkov; E. I. Plashkin; N. I. Salunin

1988-01-01

274

Learning about Simple Machines  

NSDL National Science Digital Library

This activity is designed to learn about simple machines and to have fun doing so! First, use this website to learn backround information on the basics of simple machines. Try the quiz! Simple Machines Learning Site Next, play a game that tests your ability to identify simple machines.... Edheads: Simple Machines Finally, view this video to see how students your age used applied simple machines to do a cool task... Building Simple Machines: A Glass of Milk, Please ...

Keller, Mrs.

2010-01-17

275

Composite Pressure Vessel Variability in Geometry and Filament Winding Model.  

National Technical Information Service (NTIS)

Composite pressure vessels (CPVs) are used in a variety of applications ranging from carbon dioxide canisters for paintball guns to life support and pressurant storage on the International Space Station. With widespread use, it is important to be able to ...

N. J. Greene S. J. Green

2012-01-01

276

One Half Million Mile Solar Filament  

NASA Video Gallery

NASA’s Solar Dynamics Observatory (SDO) captures a very long, whip-like solar filament extending over half a million miles in a long arc above the sun’s surface. Filaments are cooler clouds of solar material that are tethered above the sun’s surface by unstable magnetic forces. The image and video, which covers August 6-8, 2012 show the filament as a darker strand that has been in view for several days. Towards the end of the video part of the filament seems to break away, but its basic length and shape seem to have remained mostly intact.

Holly Zell

2012-08-10

277

Sensing combustion intermediates by femtosecond filament excitation.  

PubMed

Simultaneous monitoring of multiple combustion intermediates using femtosecond filament-induced nonlinear spectroscopy is demonstrated. Clean fluorescence emissions from free radicals CH, CN, NH, OH, and C(2), as well as atomic C and H, are observed when a femtosecond filament is formed in the laminar ethanol/air flame on an alcohol burner. The fluorescence signals of these species are found to vary as functions of the position of interaction of the filament with the flame along the vertical axis of the central combusting flow, opening up a possibility for remote combustion diagnostic in engines by the excitation of femtosecond laser filament. PMID:23595448

Li, He-Long; Xu, Huai-Liang; Yang, Bo-Si; Chen, Qi-Dai; Zhang, Tao; Sun, Hong-Bo

2013-04-15

278

Measurement of birefringence inside a filament  

SciTech Connect

We quantified the ultrafast birefringence induced in the filament in an atomic gas by measuring the filament-induced polarization rotation of a probe pulse. Based on the dephasing of the probe's orthogonal polarization components in argon, the experiment was done at 1 atm by copropagating a linearly polarized 400-nm probe pulse with an 800-nm pump pulse which generated the filament. The probe's elliptical polarization states were shown under various initial pump-probe polarization schemes. These states were verified by comparing the filament-induced probe polarization rotation angle and the ellipticity of the probe polarization.

Yuan Shuai [Centre d'Optique, Photonique et Laser (COPL) et Departement de physique, de genie physique et d'optique, Universite Laval, Quebec, Quebec G1V 0A6 (Canada); State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China); Wang, Tie-Jun; Chin, See Leang [Centre d'Optique, Photonique et Laser (COPL) et Departement de physique, de genie physique et d'optique, Universite Laval, Quebec, Quebec G1V 0A6 (Canada); Kosareva, Olga; Panov, Nikolay; Makarov, Vladimir [International Laser Center and Faculty of Physics, Lomonosov Moscow State University, Moscow (Russian Federation); Zeng Heping [State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China)

2011-07-15

279

Demolition of a hospital building by controlled explosion: the impact on filamentous fungal load in internal and external air  

Microsoft Academic Search

The demolition of a maternity building at our institution provided us with the opportunity to study the load of filamentous fungi in the air. External (nearby streets) and internal (within the hospital buildings) air was sampled with an automatic volumetric machine (MAS-100 Air Samplair) at least daily during the week before the demolition, at 10, 30, 60, 90,120, 180, 240,

E. Bouza; T. Peláez; J. Pérez-Molina; M. Mar??n; L. Alcalá; B. Padilla; P. Muñoz

2002-01-01

280

On the Fatigue Analysis of Wind Turbines  

SciTech Connect

Modern wind turbines are fatigue critical machines that are typically used to produce electrical power from the wind. Operational experiences with these large rotating machines indicated that their components (primarily blades and blade joints) were failing at unexpectedly high rates, which led the wind turbine community to develop fatigue analysis capabilities for wind turbines. Our ability to analyze the fatigue behavior of wind turbine components has matured to the point that the prediction of service lifetime is becoming an essential part of the design process. In this review paper, I summarize the technology and describe the ''best practices'' for the fatigue analysis of a wind turbine component. The paper focuses on U.S. technology, but cites European references that provide important insights into the fatigue analysis of wind turbines.

Sutherland, Herbert J.

1999-06-01

281

A 34-meter VAWT (Vertical Axis Wind Turbine) point design  

Microsoft Academic Search

The Wind Energy Division at Sandia National Laboratories recently completed a point design based on the 34-m Vertical Axis Wind Turbine (VAWT) Test Bed. The 34-m Test Bed research machine incorporates several innovations that improve Darrieus technology, including increased energy production, over previous machines. The point design differs minimally from the Test Bed; but by removing research-related items, its estimated

T. D. Ashwill; D. E. Berg; H. M. Dodd; M. A. Rumsey; H. J. Sutherland; P. S. Veers

1991-01-01

282

The WSRT virgo filament survey  

NASA Astrophysics Data System (ADS)

In the last few years, the realization has emerged that the universal baryons are almost equally distributed by mass in three components: (1) galactic concentrations, (2) a warm-hot intergalactic medium (WHIM) and (3) a diffuse intergalactic medium. These three components are predicted by hydrodynamical simulations and are probed by QSO absorption lines. To observe the WHIM in neutral hydrogen, observations are needed which are deeper than log(NHI) = 18. The WHIM should appear as a Cosmic Web, underlying the galaxies with higher column densities. We have used the WSRT to simulate a filled aperture by observing at very high hour angles, to reach very high column density sensitivity. To achieve even higher image fidelity, an accurate model of the WSRT primary beam was developed. This will be used in the joint deconvolution of the observations. To get a good overview of the distribution and kinematics of the Cosmic Web, a deep survey of 1500 square degrees of sky was undertaken, containing the galaxy filament extending between the Local Group and the Virgo Cluster. The auto-correlation data have been reduced and has an RMS of ?NHI = 4.2 × 1016 cm-2 over 20 km s-1. Several sources have been tentatively detected, which were previously unknown, as well as an indication for diffuse intergalactic filaments.

Popping, A.; Braun, R.

2007-02-01

283

Nonlinear Theory of Synchronous Machines On-Load  

Microsoft Academic Search

The usual two-reaction theory of synchronous machines yields results that neglect to take saturation into account. Based on a method developed in a companion paper [1], the radial airgap induction is found in synchronous machines when supplying balanced loads. The armature currents are considered to be distributed uniformly in the upper and lower layer of the armature windings. The partial

E. A. Erdelyi; S. V. Ahamed; R. E. Hopkins

1966-01-01

284

A new thermal model for EV induction machine drives  

Microsoft Academic Search

This paper introduces a new thermal model that can be used for design, protection, efficiency maximization, and speed estimation of an electric vehicle machine drive. The model can predict the winding temperature even in transient conditions. The proposed thermal model of the machine is represented by an equivalent electric circuit. Then the thermal equations are derived and used for temperature

B. Asaii; B. Moghtaderi; S. Sathiakumar; D. F. Gosden

1996-01-01

285

Permanent magnet brushless machine for a hybrid electric scooter  

Microsoft Academic Search

The paper presents the design and analyze of a permanent magnet brushless machine for a hybrid electric scooter. Different combinations of slots number, magnetic poles, and concentrated windings are tested based on the speed-cycle and power-cycle of the scooter. A machine prototype has been build. The experimental data are used to validate the simulation model. A method of increasing the

Paul Minciunescu; Relu Balaban; Corina Minciunescu; Mihaela Chefneux

2011-01-01

286

Viscoelastic properties of vimentin compared with other filamentous biopolymer networks  

Microsoft Academic Search

The cytoplasm of vertebrate cells contains three distinct filamentous biopolymers, the microtu- bules, microfilaments, and intermediate filaments. The basic structural elements of these three filaments are linear polymers of the proteins tubulin, actin, and vimentin or another related intermediate filament pro- tein, respectively. The viscoelastic properties of cyto- plasmic filaments are likely to be relevant to their biologic function, because

Paul A. Janmey; Ursula Euteneuer; Peter Traub; Manfred Schliwa

1991-01-01

287

Influence of Filament Geometry on Hot Filament Growth of Diamond Films.  

National Technical Information Service (NTIS)

The influence of filament geometry on growth rate and morphology has been observed on diamond films deposited on single crystal silicon substrates in a hot filament CVD reactor. Single and dual helical W filaments having 5, 10, or 15 turns and CH4 :H2 rat...

A. Felfman E. N. Farabaugh L. Robins

1991-01-01

288

Tether Cutting Action in Two Sigmoidal Filaments  

NASA Astrophysics Data System (ADS)

The impressive S (or inverse-S) mark appearing on the lower corona, called sigmoid, is known as the manifestation of highly sheared magnetic structures (Rust and Kumar 1996). Recent studies using Yohkoh Soft X-ray Telescope (SXT; Tsuneta et al. 1991) has indicated that soft X-ray sigmoids, i.e., hot (>= 2MK) S-shaped features, are strongly linked with eruptive phenomena, such as filament eruptions, flares, and coronal mass ejections (CMEs) (Sterling and Hudson 1997; Hudson et al. 1998; Canfield et al. 1999). However, previous papers have focused on the magnetic topology (e.g., helicity, shear buildup) of the sigmoid and connection with the resultant CME (e.g., missing mass deduced from dimming), and thus the physical process involved in the sigmoid formation and eruption is still not well addressed (e.g., van Driel-Gesztelyi et al. 2000). In this paper, we present observations of two sigmoidal filaments, in which development of the cool (~104 K) sigmoids was well resolved with the high-cadence H ? and microwave images (<= 30 sec). One is an active region filament and the other is a quiet region filament, whose long term evolution was reported by Glover et al. (2001). Both filaments were overlying the magnetic neutral line and their activities were associated with GOES B class flares. Comparison of SXT images and H ? images illustrates that each filament almost coincides with a soft X-ray long structure that is apparently consisted of two short loops. The key features commonly observed in these filaments can be summarized as follows: i) The initial activity (small brightening) started at the middle of the sigmoidal filament. ii) The activity propagated upward crossing the filament at the junction of the two soft X-ray short loops, suggesting the so-called "tether-cutting" action (Sturrock 1989; Moore and Roumelios 1992). After the flare, the active region filament extended northward and formed an inverse-S structure, which is not visible in soft X-ray, whilst in the quiet region filament, the curved southern half of the filament disappeared but the other half remained. Microwave observation provides information on the heated plasma propagating along the magnetic features. We examine thermal evolution within the sigmoidal filaments and compare the results with the tether-cutting scenario which was proposed for flare/filament eruptions. Possible magnetic reconnection that took place below the filament is discussed.

Hori, K.; Glover, A.; Akioka, M.; Ueno, S.

2002-01-01

289

Multifunctional machine tool  

Microsoft Academic Search

The functions of metal cutting machine tools have been increasing to meet the demands of high productivity and high accuracy in machining complicated and difficult parts on one machine. This paper presents a comprehensive survey of multi-functional machine tools used for metal cutting, and their kinematic configurations, control and programming technologies. Design principles and assessment of multi-functional machine tools are

T. Moriwaki

2008-01-01

290

Mining machine  

SciTech Connect

A mining machine is disclosed comprising a mobile base and a cutting head assembly at a forward end of the mobile base having a cutter drum rotatable about an output shaft disposed along the longitudinal axis of the cutter drum. A drive system for the cutting head assembly comprises at least one motor for driving at least one toothed motor pinion and a generally cylindrical combination gear having generally circular end surfaces. A bevel or face gear is formed in at least one of the end surfaces, having teeth adapted to mate with and be driven by the toothed motor pinion. The combination gear has a worm gear formed in the outside cylindrical surface, which is disposed in driving engagement with the teeth of an output gear integrally and coaxially connected to the output shaft of the cutter drum.

Becker, H.R.

1984-12-04

291

Carbon nanotube filaments in household light bulbs  

Microsoft Academic Search

Household light bulbs made from macroscopic single-walled and double-walled carbon nanotube filaments were fabricated and tested. The nanotube bulbs are found to possess several interesting features when compared to a conventional tungsten filament in safelight (36 V, 40 W), such as lower threshold voltage for light emission and higher brightness at high voltages. Electrically induced excited peaks at 407, 417,

Jinquan Wei; Hongwei Zhu; Dehai Wu; Bingqing Wei

2004-01-01

292

Development of single crystal filaments. Final report  

Microsoft Academic Search

The program just completed addresses a route to a more efficient longer-lasting electric light bulb filament. All current filaments for light bulbs are metallic in nature. They are subject to embrittlement with age (large grain growth) and relatively high vapor pressures which limits their operating temperature. There is evidence which suggests advantages to using high temperature refractory single crystal fibers

J. V. Milewski; R. A. Shoultz; M. M. Bourque-McConnell

1995-01-01

293

A First Approach to Filament Dynamics  

ERIC Educational Resources Information Center

|Modelling elastic filament dynamics is a topic of high interest due to the wide range of applications. However, it has reached a high level of complexity in the literature, making it unaccessible to a beginner. In this paper we explain the main steps involved in the computational modelling of the dynamics of an elastic filament. We first derive…

Silva, P. E. S.; de Abreu, F. Vistulo; Simoes, R.; Dias, R. G.

2010-01-01

294

Activity of BAL 4815 against filamentous fungi  

Microsoft Academic Search

Objectives: BAL 4815 is a new antifungal drug and it is the active component of the antifungal triazole BAL 8557 (the water-soluble precursor). We studied the in vitro fungistatic and fungicidal activities of BAL 4815 against 103 clinical isolates of filamentous fungi, including 51 isolates of Aspergillus spp. and 52 isolates of non-Aspergillus filamentous fungi. Methods: We evaluated the in

C. Martin de la Escalera; A. I. Aller; E. Lopez-Oviedo; A. Romero; A. I. Martos; E. Canton; J. Peman; P. Garcia Martos; E. Martin-Mazuelos

2008-01-01

295

Solar Filament Eruption Sends CME Towards Earth  

NASA Video Gallery

Full disk view of magnetic solar filament erupting during the early hours of February 24, 2012. A coronal mass ejections (CME) directed toward Earth accompanied the filament eruption. This video was taken by the Solar Dynamic Observatory in extreme ultraviolet wavelength (304 angstrom).

Holly Zell

2012-02-25

296

Process for making silver metal filaments  

DOEpatents

This invention relates to a process for making filaments of metal compounds and more particularly to a process for making silver metal filaments. The United States Government has rights to this invention pursuant to Contract No. DE-AC05-8421400 with Lockheed Martin Energy Systems, Inc. awarded by the US Department of Energy.

Bamberger, C.E.

1998-04-01

297

Enigmatic reticulated filaments in subsurface granite.  

PubMed

In the last few years, geomicrobiologists have focused their researches on the nature and origin of enigmatic reticulated filaments reported in modern and fossil samples from limestone caves and basalt lava tubes. Researchers have posed questions on these filaments concerning their nature, origin, chemistry, morphology, mode of formation and growth. A tentative microbial origin has been elusive since these filaments are found as hollow tubular sheaths and could not be affiliated to any known microorganism. We describe the presence of similar structures in a 16th century granite tunnel in Porto, Northwest Portugal. The reticulated filaments we identify exhibit fine geometry surface ornamentation formed by cross-linked Mn-rich nanofibres, surrounded by a large amount of extracellular polymeric substances. Within these Mn-rich filaments we report for the first time the occurrence of microbial cells. PMID:23760930

Miller, A Z; Hernández-Mariné, M; Jurado, V; Dionísio, A; Barquinha, P; Fortunato, E; Afonso, M J; Chaminé, H I; Saiz-Jimenez, C

2012-08-28

298

Prediction of the far field noise from wind energy farms  

NASA Astrophysics Data System (ADS)

The basic physical factors involved in making predictions of wind turbine noise and an approach which allows for differences in the machines, the wind energy farm configurations and propagation conditions are reviewed. Example calculations to illustrate the sensitivity of the radiated noise to such variables as machine size, spacing and numbers, and such atmosphere variables as absorption and wind direction are presented. It is found that calculated far field distances to particular sound level contours are greater for lower values of atmospheric absorption, for a larger total number of machines, for additional rows of machines and for more powerful machines. At short and intermediate distances, higher sound pressure levels are calculated for closer machine spacings, for more powerful machines, for longer row lengths and for closer row spacings.

Shepherd, K. P.; Hubbard, H. H.

1986-04-01

299

Kinetics of filamentous phage assembly  

NASA Astrophysics Data System (ADS)

Filamentous phages release their progeny particles by a secretory process without lysing the bacterial cell. By this process about 6 viral particles per min are secreted from each cell. We show here that when the major coat protein (gp8) is provided from a plasmid we observe a phage progeny production rate depending on the induction of gp8 by IPTG. We also show that a transfection of Escherichia coli lacking F-pili is observed using a mutant of M13 that carries an ampicillin resistance gene, and phage particles are secreted in the absence of an F-plasmid. Extruding phage was visualized by atomic force microscopy (AFM) and by transmission electron microscopy (TEM) using gold-labeled antibodies to the major coat protein.

Ploss, Martin; Kuhn, Andreas

2010-12-01

300

Actin filaments as tension sensors.  

PubMed

The field of mechanobiology has witnessed an explosive growth over the past several years as interest has greatly increased in understanding how mechanical forces are transduced by cells and how cells migrate, adhere and generate traction. Actin, a highly abundant and anomalously conserved protein, plays a large role in forming the dynamic cytoskeleton that is so essential for cell form, motility and mechanosensitivity. While the actin filament (F-actin) has been viewed as dynamic in terms of polymerization and depolymerization, new results suggest that F-actin itself may function as a highly dynamic tension sensor. This property may help explain the unusual conservation of actin's sequence, as well as shed further light on actin's essential role in structures from sarcomeres to stress fibers. PMID:22321312

Galkin, Vitold E; Orlova, Albina; Egelman, Edward H

2012-02-01

301

Hybrid-secondary uncluttered induction machine  

DOEpatents

An uncluttered secondary induction machine (100) includes an uncluttered rotating transformer (66) which is mounted on the same shaft as the rotor (73) of the induction machine. Current in the rotor (73) is electrically connected to current in the rotor winding (67) of the transformer, which is not electrically connected to, but is magnetically coupled to, a stator secondary winding (40). The stator secondary winding (40) is alternately connected to an effective resistance (41), an AC source inverter (42) or a magnetic switch (43) to provide a cost effective slip-energy-controlled, adjustable speed, induction motor that operates over a wide speed range from below synchronous speed to above synchronous speed based on the AC line frequency fed to the stator.

Hsu, John S. (Oak Ridge, TN)

2001-01-01

302

Ultrasonic analysis of Kevlar-epoxy filament wound spherical test specimens  

SciTech Connect

Increased use of composite materials in enclosed geometries such as cylindrical, spherical, or conical shapes has led to the desire to transfer and further develop the most promising nondestructive evaluation (NDE) techniques used on nonenclosed geometries to enclosed geometries. Known defects were placed within spherical Kevlar-epoxy filament wound test specimens to determine the extent to which they could be detected. These defects included Teflon shim-simulated delaminations, macrosphere-simulated voids, dry-band sets, variable tension, Kevlar 29 fiber, and an alternate high void content winding pattern. Ultrasonic C-scan analysis of Kevlar-epoxy filament wound spheres was performed to determine detectability of normal winding patterns and implanted flaw conditions in the composite using this technique. Ultrasonic waveform analysis was performed in both the time and frequency domains to determine the detectability and locatability of structural flaws within the composite.

Brosey, W.D.

1984-12-06

303

Simple Machines - Mechanical Advantage  

NSDL National Science Digital Library

This video uses working simple machines to demonstrate how to calculate mechanical advantage. Suitable for any school program involving simple machines. Demonstrates pulley systems including a chain block.

2007-01-01

304

Parallel machines scheduling with machine shutdowns  

Microsoft Academic Search

We study the nonpreemptive parallel machines scheduling problem where some of the machines are planned to be shutdown. We apply LPT algorithm to the problem and analyze its performance. Our analysis shows that the makespan of the LPT schedule is bounded by twice the optimum makespan if no more than half of the machines are allowed to be shutdown simultaneously.

H.-C. Hwang; S. Y. Chang

1998-01-01

305

A Method for Evaluation of Transient and Steady State Performance in Saturated Squirrel Cage Induction Machines  

Microsoft Academic Search

A brief survey of the application of the magnetic equivalent circuit method in evaluation of steady and transient states in induction machines is described in this paper. Taking into account machine geometry, type of windings, rotor skewing, magnetizing curve etc., this method is able to solve transients in ac machines. Sample calculations are provided, showing the influence of the number

Vlado Ostovic

1986-01-01

306

Torque ripple analysis of a 42V fault tolerant six-phase permanent magnet synchronous machine  

Microsoft Academic Search

This paper presents an analysis of the torque ripple of a six-phase fault tolerant permanent magnet synchronous machine (PMSM6) for electrical power steering system (EPS) applications. Opened stator phase is the realistic fault condition that can be imagined for a machine fed by a power converter drive system. The behavior of the machine was analyzed under three different winding fault

Arthur Matyas; Gerard Aroquiadassou; Augustin Mpanda-Mabwe; Claudia Martis; Karoly Biro

2010-01-01

307

Stereoscopic Analysis of STEREO/EUVI Observations of May 19, 2007 Erupting Filament  

NASA Astrophysics Data System (ADS)

A filament eruption, associated with a B9.5 flare, was observed by the Solar TERrestrial Relations Observatory (STEREO) on May 19, 2007, beginning at about 13 UT in AR10956. Analysis of remote and in situ observations indicate that this event is the most probable source of an interplanetary magnetic cloud observed by the Wind and STEREO B spacecraft on 2007 May 21-22. Here, we use observations from the SECCHI/EUVI telescopes to analyze the behavior of the filament before and during the eruption and to study its relation to other solar signatures of the CME event. At this time, STEREO A and B were sufficiently separated to determine the three- dimensional structure of the filament using stereoscopy. The filament could be followed in SECCHI/EUVI 304 Angstrom stereoscopic data from about 12 hours before to about 2 hours after the eruption. Although the filament has episodes of activity during this period, no dramatic pre-eruption warning signal is seen. Other results from stereoscopic analysis of STEREO/ EUVI data will also be presented. Copyright 2008 California Institute of Technology. Government sponsorship acknowledged.

Liewer, P. C.; Dejong, E. M.; Hall, J. R.; Huttunen, K. J.; Howard, R. A.; Vourlidas, A.; Thompson, W. T.

2008-05-01

308

Development of a Vacuum Bagging Technique for Autoclave Curing of Filament Wound Thin-Walled Tubes  

Microsoft Academic Search

The investigation of techniques for the manufacture of hoop wound composite tubes for use as in-plane shear specimens was undertaken. The principle concerns were achieving a smooth surface finish, uniform wall thickness, acceptable laminate consolidation and minimal defects. Filament winding of Hercules AS4\\/3501-6 12K pre-preg tow was used to manufacture 19 hoop wound thin-walled tubes. Four main vacuum bagging techniques

T. Dickson; S. Lee; M. Munro

1995-01-01

309

DC Machine  

NSDL National Science Digital Library

The effect of the commutator is to produce a fixed spatial distribution of current directions in the armature conductors (shown as blue & green circles) independent of shaft rotation. The field created by these currents (armature reaction) is vertically directed along the quadrature axis. The field established by the excitation of the stator poles is directed along the horizontal direct axis. This package presents computer models of electric machines based on the space vector formulation leading to the assessment of the dynamic performance of open- and closed-loopac and dc drive systems. The Simulink/Matlab implementation is adopted because of its inherent integration of vectorized system representations in block diagram form, of numerical analysis methods, of graphical portrayal of time evolutions of signals combined with the simple realization of the functionality of controllers and power electronic excitations. The development of Simulink models of drive assemblies is a relatively simple task consisting of combining input-output block representation of the various components making up the system; these blocks can readily be reused (utilizing standard copy-and-paste techniques) to modify the system components or the configuration of the system. This approach provides a powerful design tool because of the ease of observing the effects of parameters modifications and of differing system configurations and control strategies.

Riaz, Mahmoud

2012-08-29

310

Modeling stochastic wind loads on vertical axis wind turbines  

NASA Astrophysics Data System (ADS)

The Vertical Axis Wind Turbine (VAWT) is a machine which extracts energy from the wind. Since random turbulence is always present, the effect of this turbulence on the wind turbine fatigue life must be evaluated. This problem is approached by numerically simulating the turbulence and calculating, in the time domain, the aerodynamic loads on the turbine blades. These loads are reduced to the form of power and cross spectral densities which can be used in standard linear structural analysis codes. The relative importance of the turbulence on blade loads is determined.

Veers, P. S.

311

Modeling stochastic wind loads on vertical axis wind turbines  

SciTech Connect

The Vertical Axis Wind Turbine (VAWT) is a machine which extracts energy from the wind. Since random turbulence is always present, the effect of this turbulence on the wind turbine fatigue life must be evaluated. This problem is approached by numerically simulating the turbulence and calculating, in the time domain, the aerodynamic loads on the turbine blades. These loads are reduced to the form of power and cross spectral densities which can be used in standard linear structural analysis codes. The relative importance of the turbulence on blade loads is determined.

Veers, P.S.

1984-01-01

312

Modeling stochastic wind loads on vertical axis wind turbines  

SciTech Connect

The Vertical Axis Wind Turbine (VAWT) is a machine which extracts energy from the wind. Since random turbulence is always present, the effect of this turbulence on the wind turbine fatigue life must be evaluated. This problem is approached by numerically simulating the turbulence and calculating, in the time domain, the aerodynamic loads on the turbine blades. These loads are reduced to the form of power and cross spectral densities which can be used in standard linear structural analysis codes. The relative importance of the turbulence on blade loads is determined.

Veers, P.S.

1984-09-01

313

Simulation and detection of dynamic air-gap eccentricity in salient-pole synchronous machines  

Microsoft Academic Search

This paper presents the effect of dynamic air-gap eccentricity on the performance of a salient-pole synchronous machine. The modified winding function approach (MWFA) accounting for all space harmonics has been used for the calculations of machine winding inductances. In addition, the winding inductances have been calculated by the finite-element method to support those calculated by the MWFA. Relationships between stator-current-induced

Hamid A. Toliyat; Nabil A. Al-Nuaim

1999-01-01

314

The fibrillar substructure of keratin filaments unraveled  

PubMed Central

We show that intermediate-sized filaments reconstituted from human epidermal keratins appear unraveled in the presence of phosphate ions. In such unraveling filaments, up to four "4.5-nm protofibrils" can be distinguished, which are helically twisted around each other in a right- handed sense. Lowering the pH of phosphate-containing preparations causes the unraveling filaments to further dissociate into "2-nm protofilaments." In addition, we find that reconstitution of keratin extracts in the presence of small amounts of trypsin yields paracrystalline arrays of 4.5-nm protofibrils with a prominent 5.4-nm axial repeat. Limited proteolysis of intact filaments immobilized on an electron microscope grid also unveils the presence of 4.5-nm protofibrils within the filament with the same 5.4-nm axial repeat. These results, together with other published data, are consistent with a 10-nm filament model based on three distinct levels of helical organization: (a) the 2-nm protofilament, consisting of multi-chain extended alpha-helical segments coiled around each other; (b) the 4.5- nm protofibril, being a multi-stranded helix of protofilaments; and (c) the 10-nm filament, being a four-stranded helix of protofibrils.

1983-01-01

315

Modeling and control of a wind turbine driven doubly fed induction generator  

Microsoft Academic Search

This paper presents the simulation results of a grid-connected wind driven doubly fed induction machine (DFIM) together with some real machine performance results. The modeling of the machine considers operating conditions below and above synchronous speed, which are actually achieved by means of a double-sided PWM converter joining the machine rotor to the grid. In order to decouple the active

Arantxa Tapia; Gerardo Tapia; J. Xabier Ostolaza; José Ramón Sáenz

2003-01-01

316

Modeling of a BDFM-based wind turbine under unbalanced grid voltage dips  

Microsoft Academic Search

Brushless Doubly-Fed Machine (BDFM) is a machine which incorporates the robustness of the squirrel cage induction machine while having the speed and power factor control of a synchronous machine. A special kind of rotor called Nested-Loop rotor plays an important part in the BDFM, coupling the two stator fields. In future BDFM will share a large part in wind power

Pedram Sotoodeh; Hamed Gorgin; Hashem Oraee

2011-01-01

317

Dynamic behavior of variable speed wind turbines under stochastic wind  

Microsoft Academic Search

It is recognized that the most important advantage of the variable speed wind turbines (VS WTs) over the conventional constant speed (CS) machines are the improved dynamic characteristics, resulting in the reduction of the drive train mechanical stresses and output power fluctuations. In this paper alternative configurations of the electrical part of a VS WT are considered, using a squirrel

S. A. Papathanassiou; M. P. Papadopoulos

1999-01-01

318

Harnessing wind power  

NASA Astrophysics Data System (ADS)

The design goals, test results, operating mechanisms, and ultimate limits of large wind energy conversion systems (WECS) are explored. NASA is currently managing and monitoring the performance of the Mod O, Mod OA, Mod 1, and Mod 2 wind turbines, which produce from 100 kW-2.5 MWe for grid interconnection. The Mod 2 machines have a 300 ft diam rotor, begin producing at 14 mph and achieve the rated output at 20 mph. Testing has shown the necessity of incorporating partial span pitch control, a flexible shaft, yaw control, microprocessor monitored wind condition sensors, and a soft-shell tower to lower vibration hazards with WECS. Large WECS have proved to be relatively nonpolluting, although some television and radio interference is present. Institutional issues for the protection of land, of aircraft flight paths, and for utility interconnect are outlined, and large WECS development programs in Denmark, Sweden, Spain, and Germany are described.

Fagenbaum, J.

1982-04-01

319

Wind Power: A Turning Point. Worldwatch Paper 45.  

ERIC Educational Resources Information Center

|Recent studies have shown wind power to be an eminently practical and potentially substantial source of electricity and direct mechanical power. Wind machines range from simple water-pumping devices made of wood and cloth to large electricity producing turbines with fiberglass blades nearly 300 feet long. Wind is in effect a form of solar…

Flavin, Christopher

320

Wind Power: A Turning Point. Worldwatch Paper 45.  

ERIC Educational Resources Information Center

Recent studies have shown wind power to be an eminently practical and potentially substantial source of electricity and direct mechanical power. Wind machines range from simple water-pumping devices made of wood and cloth to large electricity producing turbines with fiberglass blades nearly 300 feet long. Wind is in effect a form of solar…

Flavin, Christopher

321

Axial Flux Permanent Magnet Generator with Concentrated Winding for Small Wind Power Applications  

Microsoft Academic Search

An axial flux permanent magnet machine, designed to operate as a generator in a small-scale wind-power applications, is described in this paper. The machine is realized by using consecrated stator winding with open slots and surface mounted permanent magnets on rotor disk. Such a novel generator structure is simple to construct and its performance is good; it offers sinusoidal back-emf

A. Parviainen; J. Pyrhonen; P. Kontkanen

2005-01-01

322

Membrane Buckling Induced by Curved Filaments  

NASA Astrophysics Data System (ADS)

We present a novel buckling instability relevant to membrane budding in eukaryotic cells. In this mechanism, curved filaments bind to a lipid bilayer without changing its intrinsic curvature. As more and more filaments adsorb, newly added ones are more and more strained, which destabilizes the flat membrane. We perform a linear stability analysis of filament-dressed membranes and find that the buckling threshold is within reasonable in vivo parameter values. We account for the formation of long tubes previously observed in cells and in purified systems. We study strongly deformed dressed membranes and their bifurcation diagram numerically. Our mechanism could be validated by a simple experiment.

Lenz, Martin; Crow, Daniel J. G.; Joanny, Jean-François

2009-07-01

323

Membrane buckling induced by curved filaments.  

PubMed

We present a novel buckling instability relevant to membrane budding in eukaryotic cells. In this mechanism, curved filaments bind to a lipid bilayer without changing its intrinsic curvature. As more and more filaments adsorb, newly added ones are more and more strained, which destabilizes the flat membrane. We perform a linear stability analysis of filament-dressed membranes and find that the buckling threshold is within reasonable in vivo parameter values. We account for the formation of long tubes previously observed in cells and in purified systems. We study strongly deformed dressed membranes and their bifurcation diagram numerically. Our mechanism could be validated by a simple experiment. PMID:19659322

Lenz, Martin; Crow, Daniel J G; Joanny, Jean-François

2009-07-13

324

Flotation machine  

SciTech Connect

A flotation machine is described for beneficiating minerals comprising: a vertical cylindrical chamber for circulating a flotation pulp; a downwardly tapered bottom connected to said vertical cylindrical chamber; feed pipe means for feeding the flotation pulp carrying mineral particles of fine fraction, particles of the useful ingredient of the fine fraction being capable of floating up from the volume of said aerated pulp; discharge pipe means connected to the tapered bottom near its lowest point for discharging gangue; an annular trough for collecting froth concentrate at the top of said chamber; a group of frustoconical shells each having bases of different diameters and a tapered surface secured axially in said chamber and spaced equidistantly from one another height wise of said chamber; aerator means for aerating the flotation pulp secured to the walls of said chamber and communicating therewith to provide aerated water into said chamber; means for feeding mineral particles of coarse fraction, particles of the useful ingredient of the coarse fraction being capable of floating in the froth layer of the flotation pulp, in the form of a hydrocyclone having a cylindrical casing positioned axially over said chamber and a downwardly tapering outlet directed downwardly to feed the coarse particles to said chamber; feed pipe means for feeding the flotation pulp carrying mineral particles of coarse fraction positioned tangentially at said cylindrical casing of the hydrocyclone; and evacuation means for evacuating the liquid phase of the flotation pulp positioned tangentially at said casing of the hydrocyclone over said feed pipe means and connected to said feed pipe means for feeding the flotation pulp carrying mineral particles of the fine fraction.

Zlobin, M.N.; Permyakov, G.P.; Nemarov, A.A.; Metsik, V.M.; Medetsky, J.V.; Taraban, N.T.

1993-08-10

325

Machine Shop Lathes.  

ERIC Educational Resources Information Center

This guide, the second in a series of five machine shop curriculum manuals, was designed for use in machine shop courses in Oklahoma. The purpose of the manual is to equip students with basic knowledge and skills that will enable them to enter the machine trade at the machine-operator level. The curriculum is designed so that it can be used in…

Dunn, James

326

Accelerating machines: a review  

Microsoft Academic Search

This paper presents an overview of accelerating machines. We begin by exploring the history of the accelerating machine model and the potential power that it provides. We look at a number of computations that could be performed with an accelerating machine, and review various possible implementation methods that have been proposed. Finally, we expose the limitations of accelerating machines and

Robert Fraser; Selim G. Akl

2008-01-01

327

The SERI wind energy program  

Microsoft Academic Search

The widespread implementation of wind energy is supported by conducting research and development studies. The activities fall into three general areas-planning, management and analysis; advanced and innovative concepts; and information development. In the first area, the work conducted relates to economic, application, legal, social and environmental studies which are generic and could be applied to a wide range of machine

I. E. Vas

1981-01-01

328

Natural plasmids of filamentous fungi.  

PubMed Central

Among eukaryotes, plasmids have been found in fungi and plants but not in animals. Most plasmids are mitochondrial. In filamentous fungi, plasmids are commonly encountered in isolates from natural populations. Individual populations may show a predominance of one type, but some plasmids have a global distribution, often crossing species boundaries. Surveys have shown that strains can contain more than one type of plasmid and that different types appear to be distributed independently. In crosses, plasmids are generally inherited maternally. Horizontal transmission is by cell contact. Circular plasmids are common only in Neurospora spp., but linear plasmids have been found in many fungi. Circular plasmids have one open reading frame (ORF) coding for a DNA polymerase or a reverse transcriptase. Linear plasmids generally have two ORFs, coding for presumptive DNA and RNA polymerases with amino acid motifs showing homology to viral polymerases. Plasmids often attain a high copy number, in excess of that of mitochondrial DNA. Linear plasmids have a protein attached to their 5' end, and this is presumed to act as a replication primer. Most plasmids are neutral passengers, but several linear plasmids integrate into mitochondrial DNA, causing death of the host culture. Inferred amino acid sequences of linear plasmid ORFs have been used to plot phylogenetic trees, which show a fair concordance with conventional trees. The circular Neurospora plasmids have replication systems that seem to be evolutionary intermediates between the RNA and the DNA worlds.

Griffiths, A J

1995-01-01

329

Amine plasma modification of polyaramid filaments  

SciTech Connect

Amine plasmas offer a method to implant amine groups into the surface structure of polyaramid filaments. These amines will react with epoxy to form covalent bonds at composite interfaces. They may also be chemically modified for reaction with other polymerizing matrices. The covalently bound interface exhibits an increased resistance to peel forces. Fractured surfaces show a change in failure mode from interface dominated to a mixture of filament splitting and matrix cracking as amine content is increased. Thus, the weak link in determining off-axis strengths of polyaramid/epoxy is changed from the interface to the filament and matrix bulk strengths after amination. The covalently bonded interface should also exhibit improved hygrothermal stability. The kinetics of amination are rapid - surface saturation occurs in 30 s; however, the kinetics are sensitive to oxygen concentration. Filament tensile strength is unchanged by amine plasma treatment times less than 600 s. Spectroscopic analysis indicates that the surface structure may, nevertheless, be substantially altered.

Allred, R.E.; Merrill, E.W.; Roylance, D.K.

1983-01-01

330

Amine Plasma Modification of Polyaramid Filaments.  

National Technical Information Service (NTIS)

Amine plasmas offer a method to implant amine groups into the surface structure of polyaramid filaments. These amines will react with epoxy to form covalent bonds at composite interfaces. They may also be chemically modified for reaction with other polyme...

R. E. Allred E. W. Merrill D. K. Roylance

1983-01-01

331

Tension of freely suspended fluid filaments.  

PubMed

Stable fluid filaments with diameters of several micrometers and slenderness ratios well above 1000 are unique objects formed by some liquid crystalline phases of bent-core mesogens. We present a technique to determine filament tensions from their deflection under defined loads. A strong temperature dependence is observed, with a minimum near the clearing temperature. Both the nonlinear relation between filament tension and diameter and the substantial increase of the tension with lower temperatures indicate contributions of volume terms, in addition to surface capillary forces. We discuss a model that relates these bulk terms to elastic forces, originating from the undulated smectic layer structure. This model can explain the origin of the filament stability. PMID:23214519

Morys, M; Trittel, T; Eremin, A; Murphy, P; Stannarius, R

2012-10-08

332

Intermediate filaments in small configuration spaces.  

PubMed

Intermediate filaments play a key role in cell mechanics. Apart from their great importance from a biomedical point of view, they also act as a very suitable micrometer-sized model system for semiflexible polymers. We perform a statistical analysis of the thermal fluctuations of individual filaments confined in microchannels. The small channel width and the resulting deflections at the walls give rise to a reduction of the configuration space by about 2 orders of magnitude. This circumstance enables us to precisely measure the intrinsic persistence length of vimentin intermediate filaments and to show that they behave as ideal wormlike chains; we observe that small fluctuations in perpendicular planes decouple. Furthermore, the inclusion of results for confined actin filaments demonstrates that the Odijk confinement regime is valid over at least 1 order of magnitude in persistence length. PMID:22463576

Nöding, Bernd; Köster, Sarah

2012-02-22

333

Intermediate Filaments in Small Configuration Spaces  

NASA Astrophysics Data System (ADS)

Intermediate filaments play a key role in cell mechanics. Apart from their great importance from a biomedical point of view, they also act as a very suitable micrometer-sized model system for semiflexible polymers. We perform a statistical analysis of the thermal fluctuations of individual filaments confined in microchannels. The small channel width and the resulting deflections at the walls give rise to a reduction of the configuration space by about 2 orders of magnitude. This circumstance enables us to precisely measure the intrinsic persistence length of vimentin intermediate filaments and to show that they behave as ideal wormlike chains; we observe that small fluctuations in perpendicular planes decouple. Furthermore, the inclusion of results for confined actin filaments demonstrates that the Odijk confinement regime is valid over at least 1 order of magnitude in persistence length.

Nöding, Bernd; Köster, Sarah

2012-02-01

334

Actin Filament Attachments for Sustained Motility In Vitro Are Maintained by Filament Bundling  

PubMed Central

We reconstructed cellular motility in vitro from individual proteins to investigate how actin filaments are organized at the leading edge. Using total internal reflection fluorescence microscopy of actin filaments, we tested how profilin, Arp2/3, and capping protein (CP) function together to propel thin glass nanofibers or beads coated with N-WASP WCA domains. Thin nanofibers produced wide comet tails that showed more structural variation in actin filament organization than did bead substrates. During sustained motility, physiological concentrations of Mg2+ generated actin filament bundles that processively attached to the nanofiber. Reduction of total Mg2+ abolished particle motility and actin attachment to the particle surface without affecting actin polymerization, Arp2/3 nucleation, or filament capping. Analysis of similar motility of microspheres showed that loss of filament bundling did not affect actin shell formation or symmetry breaking but eliminated sustained attachments between the comet tail and the particle surface. Addition of Mg2+, Lys-Lys2+, or fascin restored both comet tail attachment and sustained particle motility in low Mg2+ buffers. TIRF microscopic analysis of filaments captured by WCA-coated beads in the absence of Arp2/3, profilin, and CP showed that filament bundling by polycation or fascin addition increased barbed end capture by WCA domains. We propose a model in which CP directs barbed ends toward the leading edge and polycation-induced filament bundling sustains processive barbed end attachment to the leading edge.

Hu, Xiaohua; Kuhn, Jeffrey R.

2012-01-01

335

The hollow-cathode hot filament arc  

Microsoft Academic Search

A discharge system with a hot filament mounted inside a cylindrical hollow cathode designed to produce a low-pressure arc discharge is described together with the discharge characteristics. The combination of a hot filament and a hollow cathode allows a decrease in discharge operating voltage and a 3-4-fold increase in discharge current as compared to a configuration containing only a hot

D. P. Borisov; N. N. Koval; P. M. Schanin

1996-01-01

336

Kinks, rings, and rackets in filamentous structures  

PubMed Central

Carbon nanotubes and biological filaments each spontaneously assemble into kinked helices, rings, and “tennis racket” shapes due to competition between elastic and interfacial effects. We show that the slender geometry is a more important determinant of the morphology than any molecular details. Our mesoscopic continuum theory is capable of quantifying observations of these structures and is suggestive of their occurrence in other filamentous assemblies as well.

Cohen, Adam E.; Mahadevan, L.

2003-01-01

337

Crystal structure of a Rad51 filament  

Microsoft Academic Search

Rad51, the major eukaryotic homologous recombinase, is important for the repair of DNA damage and the maintenance of genomic diversity and stability. The active form of this DNA-dependent ATPase is a helical filament within which the search for homology and strand exchange occurs. Here we present the crystal structure of a Saccharomyces cerevisiae Rad51 filament formed by a gain-of-function mutant.

Adam B Conway; Thomas W Lynch; Ying Zhang; Gary S Fortin; Cindy W Fung; Lorraine S Symington; Phoebe A Rice

2004-01-01

338

Origins of Elasticity in Intermediate Filament Networks  

NASA Astrophysics Data System (ADS)

Intermediate filaments are common structural elements found in abundance in all metazoan cells, where they form networks that contribute to the elasticity. Here, we report measurements of the linear and nonlinear viscoelasticity of networks of two distinct intermediate filaments, vimentin and neurofilaments. Both exhibit predominantly elastic behavior with strong nonlinear strain stiffening. We demonstrate that divalent ions behave as effective cross-linkers for both networks, and that the elasticity of these networks is consistent with the theory for that of semiflexible polymers.

Lin, Yi-Chia; Yao, Norman Y.; Broedersz, Chase P.; Herrmann, Harald; Mackintosh, Fred C.; Weitz, David A.

2010-02-01

339

Consequence of filamentation on stimulated Raman scattering  

Microsoft Academic Search

In a plasma with long density scale length, a laser beam breaks up into a number of filaments, each having a size a--c\\/..omega..\\/sub p\\/. The process of stimulated Raman scattering in these filaments involves a backscattered light wave of radial extent --a and a Langmuir wave of extent b--(alambda\\/sub D\\/)¹\\/sup \\/\\/²<

C. S. Liu; V. K. Tripathi

1986-01-01

340

Bending of nanoscale filament assemblies by elastocapillary densification  

Microsoft Academic Search

We report a mechanism by which nanoscale filaments self-assemble into asymmetric aggregates by elastocapillary action. Specifically, capillary rise of liquid into an asymmetric pattern of vertically aligned filaments causes the filaments to deflect laterally during elastocapillary densification. We quantitatively show that the lateral deflection can be controlled precisely by the pattern shape and the coupling strength among the filaments. We

Zhouzhou Zhao; Sameh H. Tawfick; Sei Jin Park; Michael de Volder; A. John Hart; Wei Lu

2010-01-01

341

Electron Transport Regulates Cellular Differentiation in the Filamentous Cyanobacterium Calothrix  

Microsoft Academic Search

Differentiation of the filamentous cyanobacteria Calolhfix sp strains PCC 7601 and PCC 7504 is regulated by light spec- tral quality. Vegetative filaments differentiate motile, gas-vacuolated hormogonia after transfer to fresh medium and incubation under red light. Hormogonia are transient and give rise to vegetative filaments, or to heterocystous filaments if fixed nitrogen is lacking. If incubated under green light after

Douglas Campbell; Jean Houmard; Nicole Tandeau de Marsac

1993-01-01

342

Structural changes of tungsten heating filaments during CVD of diamond  

Microsoft Academic Search

Hot tungsten filaments (>2000°C) are used for the activation of the gas phase during hot filament chemical vapor deposition (CVD) of diamond. In the present investigation, technically pure and doped tungsten filaments were subjected to typical process conditions. The changes in the tungsten filaments microstructure were investigated. During the first 60 s, a rapid transformation of W into W2C occurs

E Zeiler; S Schwarz; S. M Rosiwal; R. F Singer

2002-01-01

343

Wind power  

Microsoft Academic Search

The fundamentals of wind power utilization are described with emphasis placed on the information needed to determine the basic geometry of wind power devices and to discuss the availability of wind for power generation. The economics and social acceptance of wind power systems at the present time are analyzed.

G. M. Bragg

1979-01-01

344

EVIDENCE FOR MIXED HELICITY IN ERUPTING FILAMENTS  

SciTech Connect

Erupting filaments are sometimes observed to undergo a rotation about the vertical direction as they rise. This rotation of the filament axis is generally interpreted as a conversion of twist into writhe in a kink-unstable magnetic flux rope. Consistent with this interpretation, the rotation is usually found to be clockwise (as viewed from above) if the post-eruption arcade has right-handed helicity, but counterclockwise if it has left-handed helicity. Here, we describe two non-active-region filament events recorded with the Extreme-Ultraviolet Imaging Telescope on the Solar and Heliospheric Observatory in which the sense of rotation appears to be opposite to that expected from the helicity of the post-event arcade. Based on these observations, we suggest that the rotation of the filament axis is, in general, determined by the net helicity of the erupting system, and that the axially aligned core of the filament can have the opposite helicity sign to the surrounding field. In most cases, the surrounding field provides the main contribution to the net helicity. In the events reported here, however, the helicity associated with the filament 'barbs' is opposite in sign to and dominates that of the overlying arcade.

Muglach, K. [ARTEP, Inc., Ellicott City, MD (United States); Wang, Y.-M. [Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States); Kliem, B., E-mail: muglach@nrl.navy.mi, E-mail: yi.wang@nrl.navy.mi, E-mail: bkliem@uni-potsdam.d [MSSL, University College London, Holmbury St. Mary, Dorking, Surrey (United Kingdom)

2009-09-20

345

Tapered tungsten filament for a long life cathode  

SciTech Connect

Directly heated tapered tungsten filament was proposed as a long life cathode of the ion source for a neutral beam injector. The shape of this filament is such that the cross section gradually increases from the positive leg to the negative leg. Numerical calculations of the time-dependent temperature distribution along the filament showed that overheating at the negative leg due to superposition of the arc discharge current on the filament current could be prevented in long pulse or dc discharges. As a result, the tapered filament may live 20 to 30 times longer than the conventional constant cross-section filament, provided the filament life were determined by evaporation only.

Tanaka, S.; Ohara, Y.

1984-10-01

346

[Phagoresistance of filamentous cyanobacteria clones].  

PubMed

The paper deals with formation regularities of phagoresistant clones of cyanobacteria in two productive virus-cell systems: heterocyst cyanobacterium Nostoc linckia--cyanophage N-2, and mutant in heterocysts strain of Anabaena variabilis--cyanophage A-1. Frequency of spontaneous formation of phagoresistant clones of cyanobacterium N. linckia varies within 1.0-8.0 x 10(-6) per a cell, A. variabilis--5.0 x 10(-6)-7.0 x 10(-7) per cell. All the studied phagoresistant clones of N. linckia have identical morpho-cultural properties and do not differ from those of the initial culture. Phagoresistant clones of A. variabilis are presented by two groups. One of them, as to its properties, does not practically differ from the wild type culture. The second group differs considerably from the initial culture A. variabilis as to a number of characteristics--time of colonies appearance, their amount, length of trichomas, specific rate of growth and biomass accumulation. Spontaneous transfer of cyanophages to the culture liquid of clones resistant forms of cyanobacteria has not been revealed. Lysis of cells of the studied clones also was not induced under the effect of mytomycin C, thermal treatment and UV-irradiation. Cyanophage N-2 is not adsorbed by the cells of resistant cloned forms of cyanobacteria N. linckia. Only nonspecific adsorption takes place on the cells of phage-resistant clones of A. variabilis of both groups: about 20% of virions introduced in the adsorption mixture. Basing on the data obtained, it is supposed that phage-resistance of stable clones of filamentous cyanobacteria under the conditions of the given experiment is determined by the structure modification of cells receptors. PMID:15104055

Mendzhul, M I; Lysenko, T G; Busakhina, I V; Shainskaia, O A

347

Performance of a 3 kW wind turbine generator with variable pitch control system  

Microsoft Academic Search

A prototype 3kW horizontal upwind type wind turbine generator of 4m in diameter has been designed and examined under real wind conditions. The machine was designed based on the concept that even small wind turbines should have a variable pitch control system just as large wind turbines, especially in Japan where typhoons occur at least once a year. A characteristic

Baku M. Nagai; Kazumasa Ameku; Jitendro Nath Roy

2009-01-01

348

Experimental study of filamentation in laser-plasma interactions  

SciTech Connect

The filamentation instability can lead to regions of increased laser intensity when a spatially nonuniform laser beam interacts with a plasma. An experimental technique will be described which identifies the density perturbation produced by filaments. The growth of filaments has been investigated and, when the laser intensity is large enough, the transverse density profile of the filament can be measured. Evidence of filament growth influenced by plasma flow and density gradients is presented. 19 refs., 4 figs.

Young, P.E.

1991-01-07

349

Extreme Kicking Machine  

NSDL National Science Digital Library

In this design challenge activity follow up to "Kicking Machine", learners add a hands-free feature to their Kicking Machine. Learners modify their kicking machine to have it either release the pendulum or rubber band while standing three feet away or have it automatically feed balls into the kicking machine, one after another. They must figure out how to integrate the new feature into the existing structure and use the design process to make sure the modified kicking machine works properly. Educators can use this activity to demonstrate simple machines and kinetic/potential energy.

Wgbh

2010-01-01

350

Hot-filament-activated chemical-vapor deposition of carbon: Film growth and filament reactions  

SciTech Connect

Pure glassy carbon films [no x-ray photoelectron spectroscopy (XPS) detectable impurities above the 0.5% level] as thick as 25 000 A have been grown on nearby silicon substrates ([ital T][gt]100 [degree]C) as a result of reactions between a hot tungsten filament and cyclopentane. Above [similar to]2500 [degree]C, cyclopentane-tungsten reactions yield a liquid W/C eutectic which limits filament operation. Below [similar to]2500 [degree]C, resistance changes of the filament and XPS spectra show such reactions form carbides and graphite. It is shown that the temperature dependence of the carbon deposition rate is similar to the sublimation rate of carbon from graphite and tungsten carbide. Moreover, it is also shown that C[sub 1], C[sub 2], and C[sub 3] (carbon monomers, dimers, and trimers) are evaporated from carbarized tungsten and also from graphite. These results suggest that carbon film growth is a consequence of evaporation of carbon from the carbarized tungsten filament, with steady-state film deposition occurring as a result of a quasisteady state in the formation and decomposition of the carbarized tungsten. Carbarization of the tungsten filament is expected for a wide variety of hydrocarbon gases, but evaporation of C species from this carbarized filament should be independent of the way it is produced. These same processes should occur at the tungsten filament during diamond film deposition using the hot-filament chemical-vapor deposition method.

Rye, R.R. (Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States))

1994-07-15

351

Design, evaluation, and fabrication of low-cost composite blades for intermediate-size wind turbines  

SciTech Connect

The low-cost composite blade program is described, involving design, evaluation and fabrication of a pair of low-cost composite rotor blades (LCCB) for the MOD-0A wind turbine. The objectives of the program were to identify low cost approaches to the design and fabrication of blades for a two-bladed 200 kW wind turbine and to assess the applicability of the techniques to larger and smaller blades. In Phase I of the program, several blade designs were developed to the point where reasonably accurate estimates could be made of the structural properties and costs of tooling and fabrication. The most cost-effective design was selected for detailed design in Phase II. Structural analysis of the selected design was performed, with assistance from NASA in some of the more specialized techniques (e.g. flutter analysis). Subelement and subscale specimens were fabricated in Phase I for testing. Blade tooling was designed and fabricated. Major items included a 60 ft D-spar mandrel and its supports, a 60 ft cure oven with a 200 kW heater, and a transverse filament tape (TFT) pre-impregnation station. Two complete blades and a partial blade for tool tryout were built. A 100 ft long ring-winder machine was designed and built.

Weingart, O.

1981-09-01

352

Minimization of Machining Allowance in Electrochemical Machining  

Microsoft Academic Search

Electrochemical machining (ECM) provides one of the best alternatives for producing complex shapes in advanced materials used in aircraft and aerospace industries. However, the reduction of sludge and memory errors continue to be major challenges for industries in addressing waste generation and accuracy improvement. This study focuses on minimizing the material to be removed by predicting minimum machining allowance and

K. P. Rajurkar; D. Zhu; B. Wei

1998-01-01

353

Tubular actin filaments in tobacco guard cells  

PubMed Central

The dynamic remodeling of actin filaments in guard cells functions in stomatal movement regulation. In our previous study, we found that the stochastic dynamics of guard cell actin filaments play a role in chloroplast movement during stomatal movement. In our present study, we further found that tubular actin filaments were present in tobacco guard cells that express GFP-mouse talin; approximately 2.3 tubular structures per cell with a diameter and height in the range of 1–3 µm and 3–5 µm, respectively. Most of the tubular structures were found to be localized in the cytoplasm near the inner walls of the guard cells. Moreover, the tubular actin filaments altered their localization slowly in the guard cells of static stoma, but showed obvious remodeling, such as breakdown and re-formation, in moving guard cells. Tubular actin filaments were further found to be colocalized with the chloroplasts in guard cells, but their roles in stomatal movement regulation requires further investigation.

Chu, Cui-Ping; Liu, Zhao-Hua; Hu, Zi-Ying

2011-01-01

354

Nebulin binding impedes mutant desmin filament assembly  

PubMed Central

Desmin intermediate filaments (DIFs) form an intricate meshwork that organizes myofibers within striated muscle cells. The mechanisms that regulate the association of desmin to sarcomeres and their role in desminopathy are incompletely understood. Here we compare the effect nebulin binding has on the assembly kinetics of desmin and three desminopathy-causing mutant desmin variants carrying mutations in the head, rod, or tail domains of desmin (S46F, E245D, and T453I). These mutants were chosen because the mutated residues are located within the nebulin-binding regions of desmin. We discovered that, although nebulin M160–164 bound to both desmin tetrameric complexes and mature filaments, all three mutants exhibited significantly delayed filament assembly kinetics when bound to nebulin. Correspondingly, all three mutants displayed enhanced binding affinities and capacities for nebulin relative to wild-type desmin. Electron micrographs showed that nebulin associates with elongated normal and mutant DIFs assembled in vitro. Moreover, we measured significantly delayed dynamics for the mutant desmin E245D relative to wild-type desmin in fluorescence recovery after photobleaching in live-cell imaging experiments. We propose a mechanism by which mutant desmin slows desmin remodeling in myocytes by retaining nebulin near the Z-discs. On the basis of these data, we suggest that for some filament-forming desmin mutants, the molecular etiology of desminopathy results from subtle deficiencies in their association with nebulin, a major actin-binding filament protein of striated muscle.

Baker, Laura K.; Gillis, David C.; Sharma, Sarika; Ambrus, Andy; Herrmann, Harald; Conover, Gloria M.

2013-01-01

355

SYMPATHETIC FILAMENT ERUPTIONS CONNECTED BY CORONAL DIMMINGS  

SciTech Connect

We present for the first time detailed observations of three successive, interdependent filament eruptions that occurred one by one within 5 hr from different locations beyond the range of a single active region. The first eruption was observed from an active region and was associated with a coronal mass ejection (CME), during which diffuse and complex coronal dimmings formed, largely extending to the two other filaments located in quiet-Sun regions. Then, both quiescent filaments consecutively underwent the second and third eruptions, while the nearby dimmings were persistent. Comparing the result of a derived coronal magnetic configuration, the magnetic connectivity between the dimmings suggested that they were caused by the joint effect of simple expansion of overlying loop systems forced by the first eruption, as well as by its erupting field interacting or reconnecting with the surrounding magnetic structures. Note that the dimming process in the first eruption indicated a weakening and partial removal of an overlying magnetic field constraint on the two other filaments, and thus one can physically connect these eruptions as sympathetic. It appears that the peculiar magnetic field configuration in our event was largely favorable to the occurrence of sympathetic filament eruptions. Because coronal dimmings are frequent and common phenomena in solar eruptions, especially in CME events, it is very likely that they represent a universal agent that can link consecutive eruptions nearby with sympathetic eruptions.

Jiang Yunchun; Yang Jiayan; Hong Junchao; Bi Yi; Zheng Ruisheng, E-mail: jyc@ynao.ac.cn [National Astronomical Observatories/Yunnan Astronomical Observatory, Chinese Academy of Sciences, P.O. Box 110, Kunming 650011 (China)

2011-09-10

356

Semantical Machine Understanding.  

National Technical Information Service (NTIS)

Semantical Machine Understanding is the foundation for automatic sense and decision making of multinational, multicultural, and coalition applications. We show an innovative semantical machine understanding system that can be installed on each node of a n...

C. Kotak C. C. Zhou Y. Zhao

2008-01-01

357

Nontraditional Machining of Beryllium.  

National Technical Information Service (NTIS)

The report deals with electrichemical machining (ECM), chemical milling, and electric-discharge machining (EDM). The general characteristics of these processes and their applications to the processing of beryllium parts are presented and covered in detail...

J. A. Gurklis

1972-01-01

358

Bibliography on Machine Foundations.  

National Technical Information Service (NTIS)

Contents: Design criteria; Theoretical solutions for the response of machine foundations to vibration; Determination of dynamic soil parameters; Design of machine foundations; Control of vibration; Abstracts and references. (Portions of this document are ...

P. J. Moore

1978-01-01

359

Electrolytic Machining Development.  

National Technical Information Service (NTIS)

An investigation of electrolytic or electrochemical machining - a metal removal method is described and the advantages over other machining methods are reported. Special emphasis was given to: investigating effects of process variables, including electrol...

J. Bayer M. A. Cummings A. U. Jollis

1964-01-01

360

The high radial velocity of an outer filament of the Helix nebula (NGC 7293)  

NASA Astrophysics Data System (ADS)

An echele spectrograph was used to obtain a series of long-slit high-resolution line profiles of H-alpha and forbidden N Ii lines from the center of the Helix nebula (NGC 7293) to the filament 11 arcmin east. This filament shows a blue-shifted velocity of about 50 km/s with respect to the nebula mean velocity, i.e. larger than the approximately 25 km/s expansion of the bright helical ring. It is suggested that this feature may be part of a radially expanding ellipsoidal shell whose long axis is inclined towards the line-of-sight. Possible mechanisms for the formation of such a high-velocity feature are discussed. Collision of a hot fast wind and a cold red-giant wind cannot easily account for the presence of multiple shells nor the high radial velocity of the outer filament. A high-mass-loss high-velocity ejection event ('superwind') at the end of the red-giant phase of an AGB star is suggested as a more probable cause or the high-velocity outer structure.

Walsh, J. R.; Meaburn, J.

1987-02-01

361

Damage Model and Progressive Failure Analyses for Filament Wound Composite Laminates  

NASA Astrophysics Data System (ADS)

Recent improvements in manufacturing processes and materials properties associated with excellent mechanical characteristics and low weight have made composite materials very attractive for application on civil aircraft structures. However, even new designs are still very conservative, because the composite failure phenomenon is very complex. Several failure criteria and theories have been developed to describe the damage process and how it evolves, but the solution of the problem is still open. Moreover, modern filament winding techniques have been used to produce a wide variety of structural shapes not only cylindrical parts, but also "flat" laminates. Therefore, this work presents the development of a damage model and its application to simulate the progressive failure of flat composite laminates made using a filament winding process. The damage model was implemented as a UMAT (User Material Subroutine), in ABAQUSTM Finite Element (FE) framework. Progressive failure analyses were carried out using FE simulation in order to simulate the failure of flat filament wound composite structures under different loading conditions. In addition, experimental tests were performed in order to identify parameters related to the material model, as well as to evaluate both the potential and the limitations of the model. The difference between numerical and the average experimental results in a four point bending set-up is only 1.6 % at maximum load amplitude. Another important issue is that the model parameters are not so complicated to be identified. This characteristic makes this model very attractive to be applied in an industrial environment.

Ribeiro, Marcelo Leite; Vandepitte, Dirk; Tita, Volnei

2013-10-01

362

The Advantage of Machines  

NSDL National Science Digital Library

In this lesson, students learn about work as defined by physical science and see that work is made easier through the use of simple machines. Already encountering simple machines everyday, students will be learn about their widespread uses in improving everyday life. This lesson serves as the starting point for the Simple Machines Unit.

Integrated Teaching And Learning Program

363

Find the Simple Machines  

NSDL National Science Digital Library

This is a web activity about simple machines. Learners will explore a lawn mower and identify six different simple machines which work together to help make our lives easier. This is an excellent activity for exploring how simple machines, and science in general, apply to learners' everyday lives.

Cosi

2000-01-01

364

A COBOL Machine  

Microsoft Academic Search

This paper describes a research project undertaken by CII. This project is sponsored by the “Comité de Recherches en Informatique” contract No CRI 72-11. In this study, we have to define a COBOL Machine and a Compilation Machine and to implement them on a medium-scale microprogrammed computer. The expected results are : performance evaluation of these machines, code compaction, COBOL

R. J. Chevance

1974-01-01

365

Apprentice Machine Theory Outline.  

ERIC Educational Resources Information Center

|This volume contains outlines for 16 courses in machine theory that are designed for machine tool apprentices. Addressed in the individual course outlines are the following topics: basic concepts; lathes; milling machines; drills, saws, and shapers; heat treatment and metallurgy; grinders; quality control; hydraulics and pneumatics;…

Connecticut State Dept. of Education, Hartford. Div. of Vocational-Technical Schools.

366

Continuous mining machine  

SciTech Connect

This patent describes a continuous mining machine for excavating a longitudinal shaft or tunnel underneath the surface of the earth, the mining machine. It comprises: transport means for moving the machine over a floor of the shaft or tunnel that is being excavated; a working platform having forward and trailing ends.

Kiefer, H.E.

1992-02-11

367

Rheology of Vimentin Intermediate Filament Networks  

NASA Astrophysics Data System (ADS)

A cell's ability to function is highly dependent on its structure and material properties - its capacity to withstand and respond to forces in its environment. The cytoskeleton, which largely determines the cellular mechanical properties, is comprised of biopolymer networks, including filamentous actin, microtubules, and intermediate filaments (IF). Intermediate filaments are much less studied than actin and microtubules. They are much more varied and specialized as well, and have been suggested as being an important platform in mechanotransduction processes in cells. It is thought that they can withstand very high strains and exhibit strain stiffening behavior. We are characterizing vimentin, a type III IF that is found in all vertebrate cells, using rheological techniques. Vimentin elasticity increases upon addition of multivalent cations, which act like molecular crosslinkers. By varying the concentration of cations, we can extract valuable information about how the networks assemble and function.

Wu, Huayin

2012-02-01

368

Solar Magnetized "Tornadoes:" Relation to Filaments  

NASA Astrophysics Data System (ADS)

Solar magnetized "tornadoes," a phenomenon discovered in the solar atmosphere, appear as tornado-like structures in the corona but are rooted in the photosphere. Like other solar phenomena, solar tornadoes are a feature of magnetized plasma and therefore differ distinctly from terrestrial tornadoes. Here we report the first analysis of solar "tornadoes" (two papers which focused on different aspects of solar tornadoes were published in the Astrophysical Journal Letters and Nature, respectively, during the revision of this Letter). A detailed case study of two events indicates that they are rotating vertical magnetic structures probably driven by underlying vortex flows in the photosphere. They usually exist as a group and are related to filaments/prominences, another important solar phenomenon whose formation and eruption are still mysteries. Solar tornadoes may play a distinct role in the supply of mass and twists to filaments. These findings could lead to a new explanation of filament formation and eruption.

Su, Yang; Wang, Tongjiang; Veronig, Astrid; Temmer, Manuela; Gan, Weiqun

2012-09-01

369

Filament Twist in F-Actin Bundles  

NASA Astrophysics Data System (ADS)

The twist state of F-actin can modify specific binding sites and influence the hierarchy of interactions in cytoskeletal regulation. F-actin in the cytoskeleton is often organized into bundles, using a wide variety of cationic molecules and actin-linking proteins. The native helical symmetry of uncondensed f-actin filaments is not necessarily the preferred symmetry of bundled filaments, which will depend on the particular bundling mechanism and the kind of condensing agent used. In order to explore the role of filament distortion in the process of bundle formation, we have carried out a series of synchrotron x-ray measurements on systems of bundled f-actin, using multivalent cations, cationic globular proteins, and actin binding proteins. Preliminary results will be presented. This work was supported by NSF DMR-0071761, DOE, DEFG02-91ER45439, the Beckman Young Investigator Program, and the Cystic Fibrosis Foundation.

Angelini, Tommy; Sanders, Lori; Wong, Gerard

2003-03-01

370

SOLAR MAGNETIZED 'TORNADOES': RELATION TO FILAMENTS  

SciTech Connect

Solar magnetized 'tornadoes', a phenomenon discovered in the solar atmosphere, appear as tornado-like structures in the corona but are rooted in the photosphere. Like other solar phenomena, solar tornadoes are a feature of magnetized plasma and therefore differ distinctly from terrestrial tornadoes. Here we report the first analysis of solar 'tornadoes' (two papers which focused on different aspects of solar tornadoes were published in the Astrophysical Journal Letters and Nature, respectively, during the revision of this Letter). A detailed case study of two events indicates that they are rotating vertical magnetic structures probably driven by underlying vortex flows in the photosphere. They usually exist as a group and are related to filaments/prominences, another important solar phenomenon whose formation and eruption are still mysteries. Solar tornadoes may play a distinct role in the supply of mass and twists to filaments. These findings could lead to a new explanation of filament formation and eruption.

Su Yang; Veronig, Astrid; Temmer, Manuela [IGAM-Kanzelhoehe Observatory, Institute of Physics, University of Graz, Universitaetsplatz 5, A-8010 Graz (Austria); Wang Tongjiang [Department of Physics, Catholic University of America, Washington, DC 20064 (United States); Gan Weiqun, E-mail: yang.su@uni-graz.at [Key Laboratory of Dark Matter and Space Astronomy, Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

2012-09-10

371

Finite-element analysis and design of a radial-field brushless PM machine utilizing soft magnetic composites  

Microsoft Academic Search

Soft magnetic composites (SMC) are emerging in electrical machine design offering the potential for innovative machine geometries and lower cost manufacturing. This paper examines the design and analysis of a SMC-based radial-field fractional-slot concentrated-winding permanent magnet machine using 2D finite-element analysis. Its performance is compared with an existing conventionally-laminated, distributed-winding baseline design for two cases, firstly with the same active

G. S. Liew; C. Tang; W. L. Soong; N. Ertugrul; D. B. Gehlert

2011-01-01

372

Wind Energy  

NSDL National Science Digital Library

Students learn about wind energy by making a pinwheel to model a wind turbine. Just like engineers, they decide where and how their turbine works best by testing it in different areas of the playground.

Integrated Teaching And Learning Program

373

Heterologous gene expression in filamentous fungi.  

PubMed

Filamentous fungi are critical to production of many commercial enzymes and organic compounds. Fungal-based systems have several advantages over bacterial-based systems for protein production because high-level secretion of enzymes is a common trait of their decomposer lifestyle. Furthermore, in the large-scale production of recombinant proteins of eukaryotic origin, the filamentous fungi become the vehicle of choice due to critical processes shared in gene expression with other eukaryotic organisms. The complexity and relative dearth of understanding of the physiology of filamentous fungi, compared to bacteria, have hindered rapid development of these organisms as highly efficient factories for the production of heterologous proteins. In this review, we highlight several of the known benefits and challenges in using filamentous fungi (particularly Aspergillus spp., Trichoderma reesei, and Neurospora crassa) for the production of proteins, especially heterologous, nonfungal enzymes. We review various techniques commonly employed in recombinant protein production in the filamentous fungi, including transformation methods, selection of gene regulatory elements such as promoters, protein secretion factors such as the signal peptide, and optimization of coding sequence. We provide insights into current models of host genomic defenses such as repeat-induced point mutation and quelling. Furthermore, we examine the regulatory effects of transcript sequences, including introns and untranslated regions, pre-mRNA (messenger RNA) processing, transcript transport, and mRNA stability. We anticipate that this review will become a resource for researchers who aim at advancing the use of these fascinating organisms as protein production factories, for both academic and industrial purposes, and also for scientists with general interest in the biology of the filamentous fungi. PMID:22958526

Su, Xiaoyun; Schmitz, George; Zhang, Meiling; Mackie, Roderick I; Cann, Isaac K O

2012-01-01

374

Wind Energy  

Microsoft Academic Search

\\u000a The kinetic energy of wind is harvested using wind turbines to generate electricity. Among various renewable energy sources,\\u000a wind energy is the second most technologically advanced renewable energy source; hydropower is the first. Although there is\\u000a a significant potential for converting wind energy to electricity, a number of issues must be addressed before it can be used\\u000a to its full

Tushar K. Ghosh; Mark A. Prelas

375

A tubular flux-switching permanent magnet machine  

NASA Astrophysics Data System (ADS)

The paper describes a novel tubular, three-phase permanent magnet brushless machine, which combines salient features from both switched reluctance and permanent magnet machine technologies. It has no end windings and zero net radial force and offers a high power density and peak force capability, as well as the potential for low manufacturing cost. It is, therefore, eminently suitable for a variety of applications, ranging from free-piston energy converters to active vehicle suspensions.

Wang, J.; Wang, W.; Clark, R.; Atallah, K.; Howe, D.

2008-04-01

376

Low cost flux-switching brushless AC machines  

Microsoft Academic Search

A low cost 3-phase DC winding excited flux-switching (FS) brushless AC machine is developed from the FS permanent magnet (FSPM) machine. The influence of stator and rotor pole number combination on its electromagnetic performance, including flux-linkage and back-emf waveforms, electromagnetic static torque, and torque-current density characteristics, are predicted by 2-D finite element analyses and validated by experiment. In addition, the

J. T. Chen; Z. Q. Zhu; S. Iwasaki; R. Deodhar

2010-01-01

377

Enhancement of filamentation postcompression by astigmatic focusing.  

PubMed

The energy scaling up of pulse postcompression is still an open issue. In this work we analyze the use of astigmatic focusing to improve the output pulses in a filamentation based postcompression setup. Unlike spherical conditions, astigmatic focusing enhances the output energy and the spectral broadening of the filament. This is due to the increase of critical power, allowing a considerable improvement of the postcompression energy and stability in a simple way. We demonstrated compression from FWHM 100 fs, 10 nm, 3 mJ input pulses to 13 fs, 142 nm, near 1 mJ pulses. PMID:21964124

Alonso, Benjamín; Borrego-Varillas, Rocío; Sola, Íñigo J; Varela, Óscar; Villamarín, Ayalid; Collados, M Victoria; Román, Julio San; Bueno, Juan M; Roso, Luis

2011-10-01

378

Height of a solar filament before eruption  

NASA Astrophysics Data System (ADS)

The relationship between the height of a solar filament observed above the photosphere before the eruption on October 21, 2010, and the critical height of a stable equilibrium of magnetic flux ropes in the coronal magnetic field is analyzed. Data from the SDO, SOHO, and STEREO space observatories observing at different viewing angles makes it possible to deduce these parameters with high accuracy. It is shown that the filament height slowly increased over several days, with the eruption occuring when the height reached the critical value of 80 Mm.

Filippov, B. P.

2013-10-01

379

Theory of Swimming Filaments in Viscoelastic Media  

NASA Astrophysics Data System (ADS)

Motivated by our desire to understand the biophysical mechanisms underlying the swimming of sperm in the non-Newtonian fluids of the female mammalian reproductive tract, we examine the swimming of filaments in the nonlinear viscoelastic upper convected Maxwell model. We obtain the swimming velocity and hydrodynamic force exerted on an infinitely long cylinder with prescribed beating pattern. We use these results to examine the swimming of a simplified sliding-filament model for a sperm flagellum. Viscoelasticity tends to decrease swimming speed, and changes in the beating patterns due to viscoelasticity can reverse swimming direction.

Fu, Henry C.; Powers, Thomas R.; Wolgemuth, Charles W.

2007-12-01

380

Structure of Flexible Filamentous Plant Viruses  

SciTech Connect

Flexible filamentous viruses make up a large fraction of the known plant viruses, but in comparison with those of other viruses, very little is known about their structures. We have used fiber diffraction, cryo-electron microscopy, and scanning transmission electron microscopy to determine the symmetry of a potyvirus, soybean mosaic virus; to confirm the symmetry of a potexvirus, potato virus X; and to determine the low-resolution structures of both viruses. We conclude that these viruses and, by implication, most or all flexible filamentous plant viruses share a common coat protein fold and helical symmetry, with slightly less than 9 subunits per helical turn.

Kendall, Amy; McDonald, Michele; Bian, Wen; Bowles, Timothy; Baumgarten, Sarah C.; Shi, Jian; Stewart, Phoebe L.; Bullitt, Esther; Gore, David; Irving, Thomas C.; Havens, Wendy M.; Ghabrial, Said A.; Wall, Joseph S.; Stubbs, Gerald (IIT); (BU-M); (Vanderbilt); (Kentucky); (BNL)

2008-10-23

381

Structure of Flexible Filamentous Plant Viruses ?  

PubMed Central

Flexible filamentous viruses make up a large fraction of the known plant viruses, but in comparison with those of other viruses, very little is known about their structures. We have used fiber diffraction, cryo-electron microscopy, and scanning transmission electron microscopy to determine the symmetry of a potyvirus, soybean mosaic virus; to confirm the symmetry of a potexvirus, potato virus X; and to determine the low-resolution structures of both viruses. We conclude that these viruses and, by implication, most or all flexible filamentous plant viruses share a common coat protein fold and helical symmetry, with slightly less than 9 subunits per helical turn.

Kendall, Amy; McDonald, Michele; Bian, Wen; Bowles, Timothy; Baumgarten, Sarah C.; Shi, Jian; Stewart, Phoebe L.; Bullitt, Esther; Gore, David; Irving, Thomas C.; Havens, Wendy M.; Ghabrial, Said A.; Wall, Joseph S.; Stubbs, Gerald

2008-01-01

382

Terahertz radiation from a laser plasma filament.  

PubMed

By the use of two-dimensional particle-in-cell simulations, we clarify the terahertz (THz) radiation mechanism from a plasma filament formed by an intense femtosecond laser pulse. The nonuniform plasma density of the filament leads to a net radiating current for THz radiation. This current is mainly located within the pulse and the first cycle of the wakefield. As the laser pulse propagates, a single-cycle and radially polarized THz pulse is constructively built up forward. The single-cycle shape is mainly due to radiation damping effect. PMID:21517604

Wu, H-C; Meyer-Ter-Vehn, J; Ruhl, H; Sheng, Z-M

2011-03-15

383

Current filamentation instability in laser wakefield accelerators.  

PubMed

Experiments using an electron beam produced by laser-wakefield acceleration have shown that varying the overall beam-plasma interaction length results in current filamentation at lengths that exceed the laser depletion length in the plasma. Three-dimensional simulations show this to be a combination of hosing, beam erosion, and filamentation of the decelerated beam. This work suggests the ability to perform scaled experiments of astrophysical instabilities. Additionally, understanding the processes involved with electron beam propagation is essential to the development of wakefield accelerator applications. PMID:21469796

Huntington, C M; Thomas, A G R; McGuffey, C; Matsuoka, T; Chvykov, V; Kalintchenko, G; Kneip, S; Najmudin, Z; Palmer, C; Yanovsky, V; Maksimchuk, A; Drake, R P; Katsouleas, T; Krushelnick, K

2011-03-08

384

Wind energy  

Microsoft Academic Search

The 1972 Solar Energy Panel of NASA and the National Science Foundation estimated the potential wind power available in the U.S. to be about 100,000 gigawatts, which is 30 times greater than the projected energy consumption for 1980. Wind energy is discussed with a view of providing a practical foundation and guide to the analysis and application of wind energy

B. Wolff; H. Meyer

1978-01-01

385

Edheads: The Compound Machine  

NSDL National Science Digital Library

This resource is a collection of interactive animations designed to help kids learn how forces and simple machines can work together to create the compound machine. Child-centered animated activities enhance understanding of how compound machines function and how they are differentiated from simple machines. The animations require the Flash plug-in (there is a link for this on the page). Additionally the site includes a glossary of important terms, lesson plans, a teacher's guide and information from people who professionally work with compound machines. This page is part of a larger collection of animated education resources for the elementary level.

2007-09-18

386

Ultraviolet Radiation Studies of Filamentous Escherichia coli B  

PubMed Central

Kantor, George J. (The Pennsylvania State University, University Park), and R. A. Deering. Ultraviolet radiation studies of filamentous Escherichia coli B. J. Bacteriol. 92:1062–1069. 1966.—Small ultraviolet (UV) doses cause Escherichia coli B to grow into long filamentous single cells. A large fraction of these filaments can recover their division ability and can form colonies under appropriate conditions. Preformed filaments can be irradiated with UV, and their ability to still produce colonies can be compared with that of irradiated normal cells. In this regard, filaments are more sensitive to UV than normal cells. Filaments can still host-cell reactivate UV-irradiated T1 phage and can regain their own deoxyribonucleic acid (DNA) synthetic ability after it has been blocked by UV. This indicates that these filaments still retain mechanisms for repairing UV-damaged DNA. Pantoyl lactone, an agent that stimulates cell-division recovery in UV-irradiated E. coli B, causes increased UV resistance for both normal and filamentous cells, with the filaments becoming more resistant than normal cells. In the absence of pantoyl lactone, irradiated filaments grow to a length of about 50 times normal and then stop growing. These long filaments cannot subsequently divide and give colonies. We conclude that the UV dose given to the preformed filaments causes an additional division lag beyond that of unirradiated filaments, and that some critical length is reached after which division recovery and colony formation is impossible. Irradiated normal cells recover before reaching this critical length.

Kantor, George J.; Deering, R. A.

1966-01-01

387

A new monitoring system for wind turbines with doubly-fed induction generators  

Microsoft Academic Search

For modern large wind farms, it is interesting to design an efficient diagnosis system oriented to wind turbine generators based on doubly-fed induction machine (DFIM). Intensive research efforts have been focused on the signature analysis to predict or to detect electrical and mechanical faults in induction machines. Different signals can be used such as voltages, currents or stray flux. In

A. Yazidi; G. A. Capolino; F. Filippetti; D. Casadei

2006-01-01

388

Investigation of self-excited induction generators for wind turbine applications  

Microsoft Academic Search

The use of squirrel-cage induction machines in wind generation is widely accepted as a generator of choice. The squirrel-cage induction machine is simple, reliable, cheap, lightweight, and requires very little maintenance. Generally, the induction generator is connected to the utility at constant frequency and operates at practically constant speed (small range of slip). The wind turbine operates in optimum efficiency

Eduard Muljadi; Jesus Sallan; M. Sanz; Charles P. Butterfield

1999-01-01

389

Geometric modeling and EM analysis of electrical windings for pulsed alternators  

Microsoft Academic Search

Pulsed alternators are state-of-the-art machines that require analytical design tools with a high level of fidelity. To meet the design needs, accurate modeling and analysis methods of the electrical windings of the machines have had to be developed. This paper will present a technique for creating accurate geometric models of racetrack style electrical windings, as well as a means of

G. A. Wedeking

2004-01-01

390

Geometric modeling and electromagnetic analysis of electrical windings for pulsed alternators  

Microsoft Academic Search

Pulsed alternators are state-of-the-art machines that require analytical design tools with a high level of fidelity. To meet the design needs, accurate modeling and analysis methods of the electrical windings of the machines have had to be developed. This paper will present a technique for creating accurate geometric models of racetrack style electrical windings, as well as a means of

G. A. Wedeking

2005-01-01

391

Low-Speed Permanent-Magnet Generators for Gearless Wind Turbines.  

National Technical Information Service (NTIS)

The paper deals with the optimization and comparison of two types of low-speed surface-mounted permanent-magnet generators for gearless wind turbines. The machines have different kinds of stator winding. The conventional machine has a three-phase, fractio...

P. Lampola

2001-01-01

392

Failure analyses of filament-wound graphite/epoxy cylinders under biaxial loading  

SciTech Connect

This paper discusses macroscopic and microscopic failure behavior of filament-wound (90/+/-20)/sub s/ graphite/epoxy thin-wall cylinders subjected to biaxial loading. Experimental results, elastic constants, and strengths are compared with analytical predictions. The Tsai-Wu failure criterion gave reasonable agreement between theoretical and experimental results. Specimens machined from failed cylinders were examined using scanning electron microscopy. Interply and intraply cracking were observed. These microscopic failure mechanisms are not accounted for in any failure criterion available in the literature. 6 references, 8 figures, 2 tables.

Marloff, R.H.; Raghava, R.S.

1985-10-01

393

Synthesis of high performance PM motors with concentrated windings  

Microsoft Academic Search

The windings concentrated around the teeth offer obvious advantages for the electrical machines with radial air-gap, because the volume of copper used in the end-windings can be reduced. The Joule losses are decreased, and the efficiency is improved. These machines are still limited to applications of sub-fractional power and they generally present a reduced number of phases. In the three-phase

Jéröme Cros; Philippe Viarouge

2002-01-01

394

Stator Current Frequency Spectra and Torque Pulsations in Induction Machines with Rotor Convertor Cascades.  

National Technical Information Service (NTIS)

In this thesis a mathematical model has been implemented on a computer and used to calculate the harmonic components of the currents and electrodynamic torque in an induction machine equipped with a convertor connected to the rotor winding. The harmonics ...

J. Hylander

1986-01-01

395

Copper Saving in the Production of Rotating Electrical Machines by Using New Organosilicon Insulation Materials.  

National Technical Information Service (NTIS)

New organosilicon sealing compounds were used to fill the cavities in the winding heads of rotating electrical machines. Organosilicon based overcoat materials were investigated. The result of the investigation showed that elastomer sealing compounds on t...

H. Kallas

1982-01-01

396

Filament Eruptions and the Impulsive Phase of Solar Flares.  

National Technical Information Service (NTIS)

We examine the observed development of filament eruptions in the impulsive phase of flares for evidence of how the eruption is driven. A possibility sometimes adopted as working hypothesis is that the filament eruption and accompanying coronal mass ejecti...

H. Zirin R. L. Moore S. R. Kane S. W. Kahler

1988-01-01

397

Investigation of Advanced Filament Wound Aircraft Landing Gear Structures.  

National Technical Information Service (NTIS)

This test program was devised to evaluate experimentally the feasibility of theuse of advanced filament wound structures in aircraft landing gear applications.Three cylindrical strut components were designed, analyzed, and fabricated from filament wound b...

S. Yurenka

1970-01-01

398

Gravitational Infall onto Molecular Filaments. II. Externally Pressurized Cylinders  

NASA Astrophysics Data System (ADS)

Two aspects of the evolution of externally pressurized, hydrostatic filaments are discussed. (1) The free-fall accretion of gas onto such a filament will lead to filament parameters (specifically, FWHM-column-density relations) inconsistent with the observations of Arzoumanian et al., except for two cases: for low-mass, isothermal filaments, agreement is found as in the analysis by Fischera & Martin. Magnetized cases, for which the field scales weakly with the density as Bvpropn 1/2, also reproduce observed parameters. (2) Realistically, the filaments will be embedded not only in gas of non-zero pressure, but also of non-zero density. Thus, the appearance of sheet-embedded filaments is explored. Generating a grid of filament models and comparing the resulting column density ratios and profile shapes with observations suggests that the three-dimensional filament profiles are intrinsically flatter than isothermal, beyond projection and evolution effects.

Heitsch, Fabian

2013-10-01

399

Design and Manufacturing of Filament Wound Thrust Cylinder.  

National Technical Information Service (NTIS)

The study on the feasibility of a CFRP (Carbon Fiber Reinforced Plastic) filament wound central cylinder for spacecraft applications is presented. Apart from design, much emphasis is given on the manufacturing of this structural element as filament windin...

C. A. L. Kemper S. R. Birjmohan B. Visser W. Rits

1992-01-01

400

Cell cycle control of yeast filamentous growth  

Microsoft Academic Search

Great progress has been made toward dissecting the signal transduction pathways and transcriptional outputs regulating yeast pseudohyphal growth. However, the mechanism underlying polarized morphogenesis in filamentous growth remains unclear. A synthesis of the data suggests that the ultimate target of these pathways is to repress the activity of the mitotic cyclin Clb2 as an antagonist of polarized growth. Here, we

Diego Rua; Brian T Tobe; Stephen J Kron

2001-01-01

401

Amine plasma modification of polyaramid filaments  

Microsoft Academic Search

Amine plasmas offer a method to implant amine groups into the surface structure of polyaramid filaments. These amines will react with epoxy to form covalent bonds at composite interfaces. They may also be chemically modified for reaction with other polymerizing matrices. The covalently bound interface exhibits an increased resistance to peel forces. Fractured surfaces show a change in failure mode

R. E. Allred; E. W. Merrill; D. K. Roylance

1983-01-01

402

Filamentous nerve cell inclusions in neurodegenerative diseases  

Microsoft Academic Search

Recent work has shown that abnormal filamentous inclusions within some nerve cells is a characteristic shared by Alzheimer's disease, some frontotemporal dementias, Parkinson's disease, dementia with Lewy bodies, multiple system atrophy, as well as Huntington's disease and other trinucleotide repeat disorders. This suggests that in each of these disorders, the affected nerve cells degenerate as a result of these abnormal

Michel Goedert; Maria Grazia Spillantini; Stephen W Davies

1998-01-01

403

Intermediate filaments: from cell architecture to nanomechanics  

Microsoft Academic Search

Intermediate filaments (IFs) constitute a major structural element of animal cells. They build two distinct systems, one in the nucleus and one in the cytoplasm. In both cases, their major function is assumed to be that of a mechanical stress absorber and an integrating device for the entire cytoskeleton. In line with this, recent disease mutations in human IF proteins

Harald Bär; Laurent Kreplak; Sergei V. Strelkov; Harald Herrmann; Ueli Aebi

2007-01-01

404

Many ways to build an actin filament.  

PubMed

Cells rely on extensive networks of protein fibres to help maintain their proper form and function. For species ranging from bacteria to humans, this 'cytoskeleton' is integrally involved in diverse processes including movement, DNA segregation, cell division and transport of molecular cargoes. The most abundant cytoskeletal filament-forming protein, F-actin, is remarkably well conserved across eukaryotic species. From yeast to human - an evolutionary distance of over one billion years - only about 10% of residues in actin have changed and the filament structure has been highly conserved. Surprisingly, recent structural data show this to be not the case for filamentous bacterial actins, which exhibit highly divergent helical symmetries in conjunction with structural plasticity or polymorphism, and dynamic properties that may make them uniquely suited for the specific cellular processes in which they participate. Bacterial actin filaments often organize themselves into complex structures within the prokaryotic cell, driven by molecular crowding and cation association, to form bundles (ParM) or interwoven sheets (MreB). The formation of supramolecular structures is essential for bacterial cytoskeleton function. We discuss the underlying physical principles that lead to complex structure formation and the implications these have on the physiological functions of cytoskeletal proteins. PMID:21362063

Popp, David; Robinson, Robert C

2011-03-14

405

Polarized Thermal Emission from Narrow Tungsten Filaments  

Microsoft Academic Search

FROM experimental work carried out by Fresnel many years ago and a theoretical investigation made by K. Schwarzschild1, it is well known that light transmitted through a narrow slit is more or less polarized. Though conditions are rather different in the case of thermal emission from a narrow filament the idea has occurred to me that polarized emission may be

Yngve Öhman

1961-01-01

406

Radial interchange motions of plasma filaments  

SciTech Connect

Radial convection of isolated filamentary structures due to interchange motions in magnetized plasmas is investigated. Following a basic discussion of vorticity generation, ballooning, and the role of sheaths, a two-field interchange model is studied by means of numerical simulations on a biperiodic domain perpendicular to the magnetic field. It is demonstrated that a blob-like plasma structure develops dipolar vorticity and electrostatic potential fields, resulting in rapid radial acceleration and formation of a steep front and a trailing wake. While the dynamical evolution strongly depends on the amount of collisional diffusion and viscosity, the structure travels a radial distance many times its initial size in all parameter regimes in the absence of sheath dissipation. In the ideal limit, there is an inertial scaling for the maximum radial velocity of isolated filaments. This velocity scales as the acoustic speed times the square root of the structure size relative to the length scale of the magnetic field. The plasma filament eventually decelerates due to mixing and collisional dissipation. Finally, the role of sheath dissipation is investigated. When included in the simulations, it significantly reduces the radial velocity of isolated filaments. The results are discussed in the context of convective transport in scrape-off layer plasmas, comprising both blob-like structures in low confinement modes and edge localized mode filaments in unstable high confinement regimes.

Garcia, O. E.; Bian, N. H.; Fundamenski, W. [Association EURATOM-Risoe National Laboratory, P.O. Box 49, OPL-128 Risoe, DK-4000 Roskilde (Denmark); School of Physics and Astronomy, University of Manchester, Manchester M60 1QD (United Kingdom); EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)

2006-08-15

407

The Contractile Filaments of the Teasel  

Microsoft Academic Search

THE observations of my son Francis on the contractile filaments protruded from the glands of Dipsacus,1 offer so new and remarkable a fact in the physiology of plants, that any confirmation of them is valuable. I hope therefore that you will publish the appended letter from Prof. Cohn, of Breslau, whom every one will allow to be one of the

Charles Darwin

1877-01-01

408

Nanomechanical properties of vimentin intermediate filament dimers  

NASA Astrophysics Data System (ADS)

The cell's cytoskeleton, providing the cell with structure and shape, consists of a complex array of structural proteins, including microtubules, microfilaments and intermediate filaments. Intermediate filaments play a crucial role in mechanotransduction and in providing mechanical stability to cells, in particular under large deformation. By utilizing molecular simulation, here we report a nanomechanical analysis of vimentin intermediate filament dimers, the basic building blocks of intermediate filaments. We describe a detailed analysis of the mechanical properties and associated deformation mechanisms, and find that mechanical stretch induces a transition from alpha-helices to beta-sheets, a phenomenon known as alpha-beta transition. A comparison of the Young's modulus predicted from simulation with experimental measurements is provided, and good agreement is found. We present an analysis of structural changes during deformation, domain unfolding patterns, rate dependence of the rupture force and associated changes in the energy landscape, and conclude with a discussion of potential implications for mechanobiology and the development of de novo protein materials.

Qin, Zhao; Kreplak, Laurent; Buehler, Markus J.

2009-10-01

409

Confining Potential when a Biopolymer Filament Reptates  

NASA Astrophysics Data System (ADS)

Using single-molecule fluorescence imaging, we track Brownian motion perpendicular to the contour of tightly entangled F-actin filaments and extract the confining potential. The chain localization presents a small-displacement Hookean regime followed by a large amplitude regime where the effective restoring force is independent of displacement. The implied heterogeneity characterized by a distribution of tube width is modeled.

Wang, Bo; Guan, Juan; Anthony, Stephen M.; Bae, Sung Chul; Schweizer, Kenneth S.; Granick, Steve

2010-03-01

410

Boron Carbide Continuous Filaments. Part II.  

National Technical Information Service (NTIS)

The purpose of this program was to develop and evaluate a process for producing continuous lengths of boron carbide filament having tensile strengths approaching 500,000 psi and elastic moduli close to that of bulk boron carbide (60-70 million psi) are be...

J. B. Higgins J. J. Gebhart A. Gatti J. M. Berry W. E. Saver

1966-01-01

411

Factors affecting filamentation in Candida albicans: changes in respiratory activity of Candida albicans during filamentation.  

PubMed Central

Glucose metabolism and respiration of Candida albicans were compared under conditions which permitted either maximal filamentous or maximal yeast growth. Changes in metabolism were monitored by comparing the quantities of ethanol produced, CO2 evolved, and oxygen consumed. Filamenting cultures produced more ethanol and less CO2 than yeasts, with oxygen consumption in the former concomitantly slower than that of the latter. Studies involving cofactors and inhibitors associated with electron transport imply that a transfer of electrons away from flavoprotein is required for maintenance of yeast morphology. Conditions consistent with a buildup of reduced flavoprotein, however, favored filament formation. These changes were expressed metabolically as a shift from an aerobic to a fermentative metabolism. The results presented are consistent with hypotheses correlating filament production with changes in carbohydrate metabolism and an interruption of electron transfer within the cell.

Land, G A; McDonald, W C; Stjernholm, R L; Friedman, L

1975-01-01

412

Phosphorylation of actin Tyr-53 inhibits filament nucleation and elongation and destabilizes filaments  

PubMed Central

Dictyostelium actin was shown to become phosphorylated on Tyr-53 late in the developmental cycle and when cells in the amoeboid stage are subjected to stress but the phosphorylated actin had not been purified and characterized. We have separated phosphorylated and unphosphorylated actin and shown that Tyr-53 phosphorylation substantially reduces actin's ability to inactivate DNase I, increases actin's critical concentration, and greatly reduces its rate of polymerization. Tyr-53 phosphorylation substantially, if not completely, inhibits nucleation and elongation from the pointed end of actin filaments and reduces the rate of elongation from the barbed end. Negatively stained electron microscopic images of polymerized Tyr-53–phosphorylated actin show a variable mixture of small oligomers and filaments, which are converted to more typical, long filaments upon addition of myosin subfragment 1. Tyr-53–phosphorylated and unphosphorylated actin copolymerize in vitro, and phosphorylated and unphosphorylated actin colocalize in amoebae. Tyr-53 phosphorylation does not affect the ability of filamentous actin to activate myosin ATPase.

Liu, Xiong; Shu, Shi; Hong, Myoung-Soon S.; Levine, Rodney L.; Korn, Edward D.

2006-01-01

413

Stable limited filamentous bulking through keeping the competition between floc-formers and filaments in balance.  

PubMed

Limited filamentous bulking (LFB) was proposed to save aeration energy consumption and enhance the capacity of filaments to degrade substrates with low concentrations in activated sludge systems. Operational parameters favorable for maintaining the LFB state were investigated in an anoxic-oxic reactor treating domestic wastewater. The experiments showed that the LFB state would deteriorate with sharply decreasing temperature, reducing substrate gradients or removing anoxic zones. The balance between filaments and floc-formers could be achieved by controlling dissolved oxygen and sludge loading rates to be in optimal ranges. Eikelboom Type 0041 and CandidatusMicrothrix parvicella were the filamentous bacteria responsible for the LFB state. However, the excess growth of Eikelboom Type 021N and Sphaerotilus natans were observed when serious bulking occurred under low substrate gradients. It was demonstrated that stable maintenance of LFB for energy saving was feasible by process control and optimization. PMID:22029958

Guo, Jianhua; Peng, Yongzhen; Wang, Shuying; Yang, Xiong; Wang, Zhongwei; Zhu, Ao

2011-09-03

414

Flexible ferromagnetic filaments and the interface with biology  

NASA Astrophysics Data System (ADS)

Flexible ferromagnetic filaments are studied both theoretically and experimentally. Two main deformation modes of the filament at magnetic field inversion are theoretically described and observed experimentally by using DNA-linked chains of ferromagnetic particles. Anomalous orientation of ferromagnetic filaments perpendicular to AC field with a frequency which is high enough is predicted and confirmed experimentally. By experimental studies of magnetotactic bacteria it is demonstrated how these properties of ferromagnetic filaments may be used to measure the flexibility of the chain of magnetosomes.

?rglis, K.; Belovs, M.; C?bers, A.

2009-04-01

415

Autonomous Reovirus Strain Classification Using Filament-Coupled Antibodies  

Microsoft Academic Search

We previously described a filament-based antibody recognition assay (FARA) that generates ELISA-like sandwich structures immobilized on a filament. FARA allows the coupling of antibodies to precise locations along a filament, on-line fluorescence detection of captured pathogen, and feedback-directed filament motion. These properties suggest that this approach might be useful as an automated means to rapidly classify unknown pathogens. In this

Gregory P. Stone; J. Denise Wetzel; Patricia K. Russ; Terence S. Dermody; Frederick R. Haselton

2006-01-01

416

A Novel Direct-Drive Dual-Structure Permanent Magnet Machine  

Microsoft Academic Search

By incorporating the merits of fractional-slot concentrated windings and Vernier machine structure, a new multi-pole dual-structure permanent magnet (PM) machine is proposed for low speed, direct-drive applications in this paper. In the outer stator, a fractional-slot concentrated winding is adopted to reduce the slot number and stator yoke height, hence saving space and improving torque density. In the inner stator,

Shuangxia Niu; S. L. Ho; W. N. Fu

2010-01-01

417

A neutral-point clamped converter system for direct-drive variable-speed wind power unit  

Microsoft Academic Search

Recent and ongoing developments in wind turbine technology indicate a trend towards utilization of high capacity (e.g., up to 5 MW) wind power units in large wind farms. Higher capacity of the wind turbine necessitates operation of the corresponding electric machine and the static converter system at higher voltages. This paper presents a neutral point diode clamped (NPC) converter system

Amirnaser Yazdani; Reza Iravani

2006-01-01

418

Break-even investment in a wind-energy-conversion system for an irrigated farm on the Texas High Plains  

Microsoft Academic Search

The purpose of this study was to quantify the benefits of using a wind energy system for irrigation. The value of wind energy was estimated on both a static basis (where the annual value of wind power was assumed to be constant over the life of the machine) and on a temporal basis (where the annual value of wind power

1981-01-01

419

Plicate Staminal Filaments in Tillandsia Subgenus Anoplophytum (Bromeliaceae)  

Microsoft Academic Search

Plication of stamina!filaments is an important diagnostic character for Tillandsia subgenus Anoplophytum (ca. 45 species). The monophyletic integrity of subgenus Anoplophytum has recently been questioned, and we conducted an anatomical investigation of plicate stamina! filaments to better characterize this putative synapomorphy. Developmental studies show that the filament plications, or folds, become visible during or soon after anthesis. Serial sections of

Timothy M. Evans; Gregory K. Brown

1989-01-01

420

Rotational model for actin filament alignment by myosin.  

PubMed

Dynamics of the actomyosin cytoskeleton regulate cellular processes such as secretion, cell division, cell motility, and shape change. Actomyosin dynamics are themselves regulated by proteins that control actin filament polymerization and depolymerization, and myosin motor contractility. Previous theoretical work has focused on translational movement of actin filaments but has not considered the role of filament rotation. Since filament rotational movements are likely sources of forces that direct cell shape change and movement we explicitly model the dynamics of actin filament rotation as myosin II motors traverse filament pairs, drawing them into alignment. Using Monte Carlo simulations we find an optimal motor velocity for alignment of actin filaments. In addition, when we introduce polymerization and depolymerization of actin filaments, we find that alignment is reduced and the filament arrays exist in a stable, asynchronous state. Further analysis with continuum models allows us to investigate factors contributing to the stability of filament arrays and their ability to generate force. Interestingly, we find that two different morphologies of F-actin arrays generate the same amount of force. We also identify a phase transition to alignment which occurs when either polymerization rates are reduced or motor velocities are optimized. We have extended our analysis to include a maximum allowed stretch of the myosin motors, and a non-uniform length for filaments leading to little change in the qualitative results. Through the integration of simulations and continuum analysis, we are able to approach the problem of understanding rotational alignment of actin filaments by myosin II motors. PMID:22326473

Miller, Callie J; Bard Ermentrout, G; Davidson, Lance A

2012-02-05

421

A complete inventory of fungal kinesins in representative filamentous ascomycetes  

Microsoft Academic Search

Complete inventories of kinesins from three pathogenic filamentous ascomycetes, Botryotinia fuckeliana, Cochliobolus heterostrophus, and Gibberella moniliformis, are described. These protein sequences were compared with those of the filamentous saprophyte, Neurospora crassa and the two yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe. Data mining and phylogenetic analysis of the motor domain yielded a constant set of 10 kinesins in the filamentous fungal

Conrad L. Schoch; James R. Aist; Olen C. Yoder; B. Gillian Turgeona

2003-01-01

422

Hardware Accelerated Segmentation of Complex Volumetric Filament Networks  

Microsoft Academic Search

We present a framework for segmenting and storing filament networks from scalar volume data. Filament networks are encountered more and more commonly in biomedical imaging due to advances in high-throughput microscopy. These data sets are characterized by a complex volumetric network of thin filaments embedded in a scalar volume field. High-throughput microscopy volumes are also difficult to manage since they

David Mayerich; John Keyser

2009-01-01

423

Some remarks on the current filament modeling of electromagnetic launchers  

Microsoft Academic Search

Current filament models have been widely used for the electromagnetic analysis of induction launchers and electromagnetic devices. Two functions of the eigenvalues of the filament parameter matrix were determined in order to evaluate the errors on the system solution induced by approximate calculations of the matrix parameters and the influence on the solution of a variation of the filament number

B. Azzerboni; E. Cardelli; M. Raugi; A. Tellini

1993-01-01

424

Automated measurements of filamentous cyanobacteria by digital image analysis  

Microsoft Academic Search

Abundance and biomass estimations of filamentous cyanobacteria often use conventional microscope mea- surements, which are highly time-consuming and provide no information on filament morphology. In this arti- cle, we describe an image analysis method developed for rapid, semiautomated or fully automated estimations of filament lengths and abundance of uncoiled cyanobacteria. The method was developed for the Baltic Sea cyanobacterium Aphanizomenon

Lisa Almesjö; Carl Rolff

425

Atomic model of a myosin filament in the relaxed state  

Microsoft Academic Search

Contraction of muscle involves the cyclic interaction of myosin heads on the thick filaments with actin subunits in the thin filaments(1). Muscles relax when this interaction is blocked by molecular switches on either or both filaments(2). Insight into the relaxed ( switched OFF) structure of myosin has come from electron microscopic studies of smooth muscle myosin molecules, which are regulated

John L. Woodhead; Fa-Qing Zhao; Roger Craig; Edward H. Egelman; Lorenzo Alamo; R. Padron

2005-01-01

426

Tungsten filament as reinforcement for heat resistant composite materials  

Microsoft Academic Search

Fine tungsten filament is a promising reinforcement for composite materials. This is due to the good properties of alloys based on tungsten - high recrystallizatio n temperature, high strength and modulus of elasticity in a fairly wide temperature range, and, particularly valuable, deformability of a continuous filament with a diameter from a few microns to several millimeters. Thin filaments are

N. M. Fonshtein; G. N. Tikhomirova; V. F. Kotov; V. I. Shvarts

1971-01-01

427

Modified Virulence of Antibiotic-Induced Burkholderia pseudomallei Filaments  

Microsoft Academic Search

Melioidosis is a life-threatening bacterial infection caused by Burkholderia pseudomallei. Some antibiotics used to treat melioidosis can induce filamentation in B. pseudomallei. Despite studies on the mechanism of virulence of the bacteria, the properties of B. pseudomallei filaments and their impact on virulence have not been investigated before. To understand the characteristics of antibiotic-induced filaments, we performed in vitro assays

Kang Chen; Guang Wen Sun; Kim Lee Chua; Yunn-Hwen Gan

2005-01-01

428

On the structure of the extruded microsporidian polar filament  

Microsoft Academic Search

The structure of the polar filament of a species of Nosema (Protozoa, Microspora) invading a sea horse, Hippocampus erectus, has been studied with the electron microscope. Filaments extruded from spores were examined on ultrathin sections and on negatively stained preparations. The extruded filament appears as a hollow tube whose walls are composed of membranes; mostly there are three membranes separated

Ji?í Lom

1972-01-01

429

Machine tool locator  

DOEpatents

Machine tools can be accurately measured and positioned on manufacturing machines within very small tolerances by use of an autocollimator on a 3-axis mount on a manufacturing machine and positioned so as to focus on a reference tooling ball or a machine tool, a digital camera connected to the viewing end of the autocollimator, and a marker and measure generator for receiving digital images from the camera, then displaying or measuring distances between the projection reticle and the reference reticle on the monitoring screen, and relating the distances to the actual position of the autocollimator relative to the reference tooling ball. The images and measurements are used to set the position of the machine tool and to measure the size and shape of the machine tool tip, and examine cutting edge wear. patent

Hanlon, John A. (Los Alamos, NM); Gill, Timothy J. (Stanley, NM)

2001-01-01

430

Performance optimization for doubly fed wind power generation systems  

SciTech Connect

Significant variation of the resource kinetic energy, in the form of wind speed, results in substantially reduced energy capture in a fixed-speed wind turbine. In order to increase the wind energy capture in the turbine, variable-speed generation (VSG) strategies have been proposed and implemented. However, that requires an expensive ac/ac power converter, which increases the capital investment significantly. Consequently, doubly fed systems have been proposed to reduce the size of the power converter and, thereby, the associated cost. Additionally, in doubly fed systems, as a fixed operating point (power and speed), power flow can be regulated between the two winding systems on the machine. This feature can by utilized to essentially minimize losses in the machine associated with the given operating point or achieve other desired performance enhancements. In this paper, a brushless doubly fed machine (BDFM) is utilized to develop a VSG wind power generator. The VSG controller employs a wind-speed-estimation-based maximum power point tracker and a heuristic-model-based maximum efficiency point tracker to optimize the power output of the system. The controller has been verified for efficacy on a 1.5-kW laboratory VSG wind generator. The strategy is applicable to all doubly fed configurations, including conventional wound-rotor induction machines, Scherbius cascades, BDFM's and doubly fed reluctance machines.

Bhowmik, S.; Spee, R.; Enslin, J.H.R.

1999-08-01

431

Wind power electrical drives for permanent magnet generators — Development in Finland  

Microsoft Academic Search

The use of permanent magnets offers freedom in machine design and the highest possible efficiencies for wind power machines. Although full power converters must be used with permanent magnet machines, these converters make it possible to fulfill even the strictest grid codes. If appropriate care is taken in selecting the exact magnetic material composition, Neodymium-Iron-Boron magnets are compatible with long

Juha J. Pyrhonen; Yulia Alexandrova; R. Scott Semken; Henry Hamalainen

2012-01-01

432

Edheads: Simple Machines  

NSDL National Science Digital Library

This interactive Flash activity invites kids to learn about simple and compound machines by investigating common household objects found in the kitchen and tool shed. The animated activities help them understand how the machines work and how to differentiate the various types of simple machine. Additionally the site provides a glossary of important terms, lesson plans and a teacher's guide. This page is part of a larger collection of game-like animations developed to teach children about science.

2007-08-16

433

OPTICAM machine design  

Microsoft Academic Search

Rank Pneumo has worked with the Center of Optics Manufacturing to design a multiple-axis flexible machining center for spherical lens fabrication. The OPTICAM\\/SM prototype machine has been developed in cooperation with the Center's Manufacturing Advisory Board. The SM will generate, fine grind, pre-polish, and center a spherical lens surface in one setup sequence. Unique features of the design incorporate machine

Jyrki T. Liedes

1992-01-01

434

The Vienna Abstract Machine  

Microsoft Academic Search

The Vienna Abstract Machine (VAM) is a Prolog machine developed at the TU Wien. In contrast to the standard implementation technique (Warren Abstract Machine - WAM), an inference in VAM is performed by unifying the goal and head immediately, instead of bypassing arguments through a register interface. We present two implemen- tations for VAM: VAM2P and VAM1P. VAM2P is well

Andreas Krall; Ulrich Neumerkel

1990-01-01

435

Machining: An Introduction  

NSDL National Science Digital Library

Basic machining processes are introduced on this site that is devoted to engineering fundamentals. Descriptions and illustrations of drilling, turning, grinding, and other common processes are provided for people with little to no prior machining knowledge. A waterjet is a non-traditional machining technology that uses high pressure streams of water with abrasive additives rather than solid cutting instruments to slice through metal and other materials.

2008-04-23

436

Prediction of Machine Tool Condition Using Support Vector Machine  

Microsoft Academic Search

Condition monitoring and predicting of CNC machine tools are investigated in this paper. Considering the CNC machine tools are often small numbers of samples, a condition predicting method for CNC machine tools based on support vector machines (SVMs) is proposed, then one-step and multi-step condition prediction models are constructed. The support vector machines prediction models are used to predict the

Peigong Wang; Qingfeng Meng; Jian Zhao; Junjie Li; Xiufeng Wang

2011-01-01

437

Design of precision desktop machine tools for meso-machining  

Microsoft Academic Search

The paper describes the classification of non-lithography based meso-manufacturing. Desktop machine tools and standard machine tools are the current manufacturing equipment for such machining scale, however desktop machines are the most economic and should achieve better accuracies. Various inherent problems and challenges in the development of highly precise desktop machine tools are discussed in this paper. A design strategy is

A. Khalid; S. Mekid

438

Debugging the virtual machine  

SciTech Connect

A computer program is really nothing more than a virtual machine built to perform a task. The program`s source code expresses abstract constructs using low level language features. When a virtual machine breaks, it can be very difficult to debug because typical debuggers provide only low level machine implementation in formation to the software engineer. We believe that the debugging task can be simplified by introducing aspects of the abstract design into the source code. We introduce OODIE, an object-oriented language extension that allows programmers to specify a virtual debugging environment which includes the design and abstract data types of the virtual machine.

Miller, P.; Pizzi, R.

1994-09-02

439

Influence of soft magnetic materials on the design and performance of tubular permanent magnet machines  

Microsoft Academic Search

This paper investigates the influence of the choice of soft magnetic material on the performance of a tubular permanent magnet machine, and quantifies the relative merits of silicon iron laminations and soft magnetic composites (SMCs). The machine is equipped with a modular stator winding and employs a quasi-Halbach magnetized moving-magnet armature. It is shown that, despite its poorer space utilization,

Jiabin Wang; David Howe

2005-01-01

440

A method for wide frequency range modeling of power transformers and rotating machines  

Microsoft Academic Search

Wide frequency range representation of power system components such as power transformers, reactors and rotating machines is mainly needed for the analysis of electromagnetic transients in power systems. In this paper, a method is presented for state space formulation of machine windings. The described procedure is completely based on external terminal impedance measurements and data related to the internal structure

A. Oguz Soysal

1993-01-01

441

Permanent magnet synchronous machines with improved energetic performances and reduced torque ripples, used for electric vehicles  

Microsoft Academic Search

The paper presents the study of two permanent magnet synchronous machines, with outer rotor, dedicated for electric scooter applications. The electrical machines will be analyzed in order to assure the most suited scooter propulsion. The variety of topology is basically obtained through specific winding configuration and poles\\/slots ratio. The design results are validated numerically through finite element method. A skewed

D. Fodorean; F. Jurca; C. Oprea; L. Szabo

2011-01-01

442

A computationally intelligent maximum torque per ampere control strategy for switched reluctance machines  

Microsoft Academic Search

While currently occupying only a niche role in industrial applications, the switched reluctance machines (SRM) unique operational characteristics could prove useful for additional engineering sectors given that inherent drawbacks are addressed. Phase winding isolation of SRMs provides greater fault tolerance when compared to the industrial standard, pulse width modulation driven induction machines. Furthermore, they may remain in a locked rotor

Furkan Akar; Fletcher Fleming; Chris S. Edrington

2012-01-01

443

Influence of slot and pole number combinations on unbalanced magnetic force in permanent magnet machines  

Microsoft Academic Search

Unbalanced magnetic forces (UMF) exist in permanent magnet machines having pole and slot numbers differed by one and two, even when there is no rotor eccentricity. In machines having pole and slot numbers differed by two, the on-load UMF results only when the single layer winding is employed and the number of coils is odd. This paper investigates the influence

Z. Q. Zhu; M. L. Mohd Jamil; L. J. Wu

2011-01-01

444

CLASSICAL AREAS OF PHENOMENOLOGY: Interaction of light filaments in air  

NASA Astrophysics Data System (ADS)

This paper analytically investigates the interaction of light filaments generated by a femtosecond laser beam in air. It obtains the Hamiltonian of a total laser field and interaction force between two filaments with different phase shifts and crossing angles. The property of the interaction force, which leads the attraction or repulsion of filaments, is basically dependent on the phase shift between filaments. The crossing angle between two filaments can only determine the magnitude of the interaction force, but does not change the property of the force.

Xi, Ting-Ting; Lu, Xin; Hao, Zuo-Qiang; Ma, Yuan-Yuan; Zhang, Jie

2009-10-01

445

Spontaneous Symmetry Breaking of a Hinged Flapping Filament Generates Lift  

NASA Astrophysics Data System (ADS)

Elastic filamentous structures found on swimming and flying organisms are versatile in function, rendering their precise contribution to locomotion difficult to assess. We show in this Letter that a single passive filament hinged on the rear of a bluff body placed in a stream can generate a net lift force without increasing the mean drag force on the body. This is a consequence of spontaneous symmetry breaking in the filament’s flapping dynamics. The phenomenon is related to a resonance between the frequency associated with the von Kármán vortex street developing behind the bluff body and the natural frequency of the free bending vibrations of the filament.

Bagheri, Shervin; Mazzino, Andrea; Bottaro, Alessandro

2012-10-01

446

Electrostatic repulsion-driven crystallization model arising from filament networks  

NASA Astrophysics Data System (ADS)

The crystallization of bundles in filament networks interacting via long-range repulsions in confinement is described by a phenomenological model. The model demonstrates the formation of the hexagonal crystalline order via the interplay of the confinement potential and the filament-filament repulsion. Two distinct crystallization mechanisms in the short- and large- screening length regimes are discussed, and the phase diagram is obtained. Simulation of large bundles predicts the existence of topological defects within the bundled filaments. This electrostatic repulsion-driven crystallization model arising from studying filament networks can even find a more general context extending to charged colloidal systems.

Yao, Zhenwei; Olvera de la Cruz, Monica

2013-04-01

447

Laser beam machining method, laser beam machining apparatus, and laser beam machining product  

US Patent & Trademark Office Database

It is an object to provide a laser beam machining method which can easily cut a machining target. The laser beam machining method irradiates laser light while positioning a focus point at the inside of a machining target to thereby form a treated area based on multiphoton absorption along a planned cutting line of the machining target inside the machining target and also form a minute cavity at a predetermined position corresponding to the treated area in the machining target.

Fukumitsu; Kenshi (Hamamatsu, JP)

2009-10-20

448

Fatigue case study and reliability analyses for wind turbines  

Microsoft Academic Search

Modern wind turbines are fatigue critical machines used to produce electrical power. To insure long term, reliable operation, their structure must be optimized if they are to be economically viable. The fatigue and reliability projects in Sandia's Wind Energy Program are developing the analysis tools required to accomplish these design requirements. The first section of the paper formulates the fatigue

Herbert J. Sutherland; Paul S. Veers

1994-01-01

449

Wind Energy Conversion Systems. A Unit of Instruction.  

ERIC Educational Resources Information Center

The number of secondary schools, colleges, and universities offering courses in wind energy machine construction, repair, and installation, continues to increase. It is the purpose of this unit to include the study of wind energy conversion systems (WECS) as an integral part of related vocational and technical curriculum materials. The unit's…

Greenwald, Martin

450

Wind Energy Conversion Systems. A Unit of Instruction.  

ERIC Educational Resources Information Center

|The number of secondary schools, colleges, and universities offering courses in wind energy machine construction, repair, and installation, continues to increase. It is the purpose of this unit to include the study of wind energy conversion systems (WECS) as an integral part of related vocational and technical curriculum materials. The unit's…

Greenwald, Martin

451

Synchronous operation of a dual-winding reluctance generator  

Microsoft Academic Search

This paper sets forth the analysis and performance characterization of the dual-winding reluctance machine fed with direct current control winding excitation operating as a generator. Saturation effect, core and harmonic losses are included in the dynamic and steady state models of the generator feeding either an impedance or a rectifier load which give calculation results that compare favorably with the

Olorunfemi Ojo; Zhiqing Wu

1997-01-01

452

Application of intelligent power module IPM in wind power system  

Microsoft Academic Search

The wind energy which is used as a kind of clean and reproducible energy, nowadays gets more and more important in the energy scarcity cases, capacity of the single machine in wind power generation continuous enlarge. Owing to the shortage of traditional inverter, to Mitsubishi PM100DSA120 for example, the basic electrical characteristics of IPM was analyzed. A design of inverter

Dantong Zhang

2010-01-01

453

Stator-flux-oriented vector control of synchronous reluctance Machines with maximized efficiency  

Microsoft Academic Search

This paper presents a position-sensorless vector torque controller designed to achieve maximum efficiency over a range of power and rotational speed for a synchronous reluctance machine. A model of the synchronous reluctance machine is presented which incorporates both winding and core losses. It is then shown that a stator-flux-oriented control scheme can achieve synchronous operation of the machine without a

Heath F. Hofmann; Seth R. Sanders; A. EL-Antably

2004-01-01

454

Drum cutter mining machine  

SciTech Connect

A drum cutter mining machine includes a machine frame with a winch having a drive wheel to engage a rack or chain which extends along the path of travel by the mining machine to propel the machine along a mine face. The mining machine is made up of discrete units which include a machine body and machine housings joined to opposite sides of the machine body. The winch is either coupled through a drive train with a feed drive motor or coupled to the drive motor for cutter drums. The machine housings each support a pivot shaft coupled by an arm to a drum cutter. One of these housings includes a removable end cover and a recess adapted to receive a support housing for a spur gear system used to transmit torque from a feed drive motor to a reduction gear system which is, in turn, coupled to the drive wheel of the winch. In one embodiment, a removable end cover on the machine housing provides access to the feed drive motor. The feed drive motor is arranged so that the rotational axis of its drive output shaft extends transversely to the stow side of the machine frame. In another embodiment, the reduction gear system is arranged at one side of the pivot shaft for the cutter drum while the drive motor therefor is arranged at the other side of the pivot shaft and coupled thereto through the spur gear system. In a further embodiment, the reduction gear system is disposed between the feed motor and the pivot shaft.

Oberste-beulmann, K.; Schupphaus, H.

1980-02-19

455

Substructure and accessory proteins in scallop myosin filaments  

PubMed Central

Native myosin filaments from scallop striated muscle fray into subfilaments of approximately 100-A diameter when exposed to solutions of low ionic strength. The number of subfilaments appears to be five to seven (close to the sevenfold rotational symmetry of the native filament), and the subfilaments probably coil around one another. Synthetic filaments assembled from purified scallop myosin at roughly physiological ionic strength have diameters similar to those of native filaments, but are much longer. They too can be frayed into subfilaments at low ionic strength. Synthetic filaments share what may be an important regulatory property with native filaments: an order- disorder transition in the helical arrangement of myosin cross-bridges that is induced on activation by calcium, removal of nucleotide, or modification of a myosin head sulfhydryl. Some native filaments from scallop striated muscle carry short "end filaments" protruding from their tips, comparable to the structures associated with vertebrate striated muscle myosin filaments. Gell electrophoresis of scallop muscle homogenates reveals the presence of high molecular weight proteins that may include the invertebrate counterpart of titin, a component of the vertebrate end filament. Although the myosin molecule itself may contain much of the information required to direct its assembly, other factors acting in vivo, including interactions with accessory proteins, probably contribute to the assembly of a precisely defined thick filament during myofibrillogenesis.

1989-01-01

456

Isolation of intermediate filament assemblies from human hair follicles  

PubMed Central

We used developing human hair follicle cells for the isolation of hard alpha-keratin structural components. Intracellular dispersions examined by electron microscopy contained both individual alpha-keratin filaments and the tactoid-like filament assemblies observed in situ organized along subfibrillar arms of macrofibrils. The assemblies of average width 47 nm were composed of closely packed alpha-keratin filaments and originated from the initial filament arrays observed in sections of developing mammalian hair follicles. We have distinguished two types of assemblies: the para-like or hexagonally packed and the ortho-like spiral or whorl type. Axial banding extended across the width of filament assemblies, which suggested that hard alpha-keratin filaments pack in lateral register and form a lattice that contains interfilamentous bridges. We observed axial banding patterns with periods ranging from 20 to 22 nm, consistent with the 22-nm periodic structure deduced from x-ray diffraction studies and present in models proposed for hard alpha-keratin and other intermediate filaments. Preliminary biochemical studies of filaments and filament assemblies indicate that they consist of the closely related group of proteins (low-sulfur proteins) ubiquitous among extracts of hard mammalian keratins. Isolated hard alpha-keratin filament assemblies provide a new and valuable structural entity for investigating the assembly mechanisms involved in the formation of the filament-matrix framework found in hard mammalian keratin appendages.

1985-01-01

457

Diamond machine tool face lapping machine  

DOEpatents

An apparatus for shaping, sharpening and polishing diamond-tipped single-point machine tools. The isolation of a rotating grinding wheel from its driving apparatus using an air bearing and causing the tool to be shaped, polished or sharpened to be moved across the surface of the grinding wheel so that it does not remain at one radius for more than a single rotation of the grinding wheel has been found to readily result in machine tools of a quality which can only be obtained by the most tedious and costly processing procedures, and previously unattainable by simple lapping techniques.

Yetter, H.H.

1985-05-06

458

Hybrid machining of Inconel 718  

Microsoft Academic Search

A new approach for machining of Inconel 718 is presented in this paper. It combines traditional turning with cryogenically enhanced machining and plasma enhanced machining. Cryogenically enhanced machining is used to reduce the temperatures in the cutting tool, and thus reduces temperature-dependent tool wear to prolong tool life, whereas plasma enhanced machining is used to increase the temperatures in the

Z. Y Wang; K. P Rajurkar; J Fan; S Lei; Y. C Shin; G Petrescu

2003-01-01

459

Combining programs and state machines  

Microsoft Academic Search

State machines consume and process actions complementary to programs issuing actions. State machines maintain a state and reply with a boolean response to each action in their interface. As state machines offer a service to programs, their interface is also called a service interface. State machines can be combined with several natural operators, thus giving rise to a state machine

Jan A. Bergstra; Alban Ponse

2002-01-01

460

In situ ellipsometric study of surface immobilization of flagellar filaments  

NASA Astrophysics Data System (ADS)

Protein filaments composed of thousands of subunits are promising candidates as sensing elements in biosensors. In this work in situ spectroscopic ellipsometry is applied to monitor the surface immobilization of flagellar filaments. This study is the first step towards the development of layers of filamentous receptors for sensor applications. Surface activation is performed using silanization and a subsequent glutaraldehyde crosslinking. Structure of the flagellar filament layers immobilized on activated and non-activated Si wafer substrates is determined using a two-layer effective medium model that accounted for the vertical density distribution of flagellar filaments with lengths of 300-1500 nm bound to the surface. The formation of the first interface layer can be explained by the multipoint covalent attachment of the filaments, while the second layer is mainly composed of tail pinned filaments floating upwards with the free parts. As confirmed by atomic force microscopy, covalent immobilization resulted in an increased surface density compared to absorption.

Kurunczi, S.; Németh, A.; Hülber, T.; Kozma, P.; Petrik, P.; Jankovics, H.; Sebestyén, A.; Vonderviszt, F.; Fried, M.; Bársony, I.

2010-10-01

461

Properties of Magnetic Neutral Lines and Filament Formation  

NASA Astrophysics Data System (ADS)

Chromospheric filaments form at a boundary (neutral lines) between opposite polarity magnetic fields. Both the total length of neutral lines and the number of filaments vary with solar cycle. However, our analysis indicates that the cycle variation in filaments is not due to the change in the total length of neutral lines. It is likely due to change in magnetic properties of neutral lines. In present study we compare properties of magnetic polarity inversion lines that have filaments above them and those without filaments, and investigate how these properties change during the solar cycle. Our results show that the gradient as well as convergence/divergence of magnetic field across neutral lines are not the major factors that determine the places of filament formation. We discuss the role of canceling magnetic features in filament formation and their cycle variation.

Karachik, N.; Pevtsov, A. A.

2011-12-01

462

Reconstitution of intermediate filaments from a higher plant.  

PubMed Central

Immunological studies have shown that plants contain intermediate-filament antigens, but it is not known whether these proteins are capable in themselves of forming filaments. To address this problem, a detergent-resistant and high-salt-insoluble fraction from carrot (Daucus carota L.) suspension cells was solubilized with 9 M-urea and then subjected to a two-step dialysis procedure, devised for the reconstitution of animal intermediate filaments. This induced the self-assembly of 10 nm filaments and large bundles of filaments. The predominant components of reconstituted material were polypeptides with apparent molecular masses between 58 and 62 kDa. These polypeptides immunoblotted with two monoclonal antibodies known to show broad cross-reactivity with intermediate filaments across the phylogenetic spectrum. This establishes that the antigens are able to self-assemble into intermediate-sized filaments. Images Fig. 1. Fig. 2.

Hargreaves, A J; Goodbody, K C; Lloyd, C W

1989-01-01

463

Effect of Armature Resistance Upon Hunting of Synchronous Machines  

Microsoft Academic Search

The ability of systems to withstand shocks, such as faults or switching operations, is much greater for small operating angles. The present paper has to do with system stability for small oscillations as contrasted with the more usual concept of stability as being its ability to withstand shocks. The analysis shows that synchronous machines without amortisseur windings and with no

C. F. Wagner

1930-01-01

464

MODELUNG OF PAN EVAPORATION USING SUPPORT VECTOR MACHINES ALGORITHM  

Microsoft Academic Search

This paper present results of pan evaporation estimations using Support Vector Machines (SVMs) based approach for the meteorological data from Manasgaon climatic station near Anand Sagar Reservoir, Shegaon. At this station four meteorological variables are measured simultaneously, namely, air temperature, wind speed, sunshine hours and relative humidity. The SVMs architecture involves in using one output parameter (i.e. evaporation) and up

S. Deswal; Mahesh Pal

2008-01-01

465

The design of fault tolerant machines for aerospace applications  

Microsoft Academic Search

This paper discusses the design of a fault tolerant electric motor for an aircraft main engine fuel pump. The motor in question is a four phase fault tolerant motor with separated windings and a six pole permanent magnet rotor. Methods of reducing machine losses in both the rotor and stator are introduced and discussed. The methods used to calculate rotor

G. J. Atkinson; B. C. Mecrow; A. G. Jack; D. J. Atkinson; P. Sangha; M. Benarous

2005-01-01

466

Composite ceramic superconducting filaments for superconducting cable  

NASA Astrophysics Data System (ADS)

This program has established the feasibility of manufacturing composite ceramic superconducting filaments for superconducting cable, based on copper-clad YBa2Cu3O7-x ceramic powders, to render the material in the form of flexible fine diameter green fibers by dry spinning, and to rapidly sinter the fibers to produce filaments with transport Jc as high as 2800 A/sq.cm. The sintered fibers can be handled, and the feasibility of cladding these fibers with copper by electrodeposition has been supported. The fibers are spun from a suspension of powder in a mixture of solvents containing several acrylic polymers, a plasticizer, a cross-linking agent, and a dispersant. The dry green fiber is a flexible monofilament containing 49 to 55 volume percent (85 to 87 weight percent) ceramic powder in a polymeric matrix. A multiple zone sintering process was developed to rapidly densify the YBa2Cu3O7-x fibers.

Halloran, John W.

1988-07-01

467

Viscoelastic response of contractile filament bundles  

NASA Astrophysics Data System (ADS)

The actin cytoskeleton of adherent tissue cells often condenses into filament bundles contracted by myosin motors, so-called stress fibers, which play a crucial role in the mechanical interaction of cells with their environment. Stress fibers are usually attached to their environment at the endpoints, but possibly also along their whole length. We introduce a theoretical model for such contractile filament bundles which combines passive viscoelasticity with active contractility. The model equations are solved analytically for two different types of boundary conditions. A free boundary corresponds to stress fiber contraction dynamics after laser surgery and results in good agreement with experimental data. Imposing cyclic varying boundary forces allows us to calculate the complex modulus of a single stress fiber.

Besser, Achim; Colombelli, Julien; Stelzer, Ernst H. K.; Schwarz, Ulrich S.

2011-05-01

468

Theory of swimming filaments in viscoelastic media  

NASA Astrophysics Data System (ADS)

Microorganisms often encounter and must move through complex media. What aspects of propulsion are altered when swimming in viscoelastic gels and fluids? Motivated by the swimming of sperm through the mucus of the female mammalian reproductive tract, we examine the swimming of filaments in nonlinearly viscoelastic fluids. We obtain the swimming velocity and hydrodynamic force exerted on an infinitely long cylinder with prescribed beating pattern. We apply these results to study the swimming of a simplified sliding-filament model for a sperm flagellum. Viscoelasticity tends to decrease swimming speed. The viscoelastic response of the fluid can change the shapes of beating patterns, and changes in the beating patterns can even lead to reversal of the swimming direction.

Fu, Henry

2008-03-01

469

Flapping dynamics of a flexible filament  

NASA Astrophysics Data System (ADS)

This paper investigates the dynamics of the flapping regime of a filament placed in a two-dimensional soap-film flow for different filament lengths and flow speeds. It was found that the onset of flapping is quasiperiodic, with the main flapping amplitude and frequency modulated by low-amplitude, low-frequency oscillation. At higher flow velocities, the oscillation becomes chaotic. The transition to chaos occurs via the quasiperiodic route to chaos. A new bistability phenomenon was discovered in which the system alternates between the stretched-straight and oscillatory states, which is here referred to as “switching oscillation.” Unlike some previously reported forms of bistability, in this case the system alternates between the two states continuously, without any external perturbation.

Ait Abderrahmane, H.; Paidoussis, M. P.; Fayed, M.; Ng, H. D.

2011-12-01

470

Active compaction of crosslinked driven filament networks*  

PubMed Central

The contractile ability of active materials relies on the interplay of force-exerting and force-bearing structures. However, the complexity of interactions and limited parameter control of many model systems are major obstacles in advancing our understanding of the underlying fundamental principles. To shed light on these principles we introduce and analyse a minimal reconstituted system, consisting of highly concentrated actin filaments that are crosslinked by ?-actinin and actively transported in the two-dimensional geometry of a motility assay. This minimal system actively compacts and evolves into highly compact fibres that exceed the length of the individual filaments by two orders of magnitude. We identify the interplay between active transport and crosslinking to be responsible for the observed active compaction. This enables us to control the structure and the length scale of active compaction.

Schaller, V.; Hammerich, B.; Bausch, A.R.

2013-01-01

471

Experiments on the Propagation of Plasma Filaments  

SciTech Connect

We investigate experimentally the motion and structure of isolated plasma filaments propagating through neutral gas. Plasma filaments, or 'blobs,' arise from turbulent fluctuations in a range of plasmas. Our experimental geometry is toroidally symmetric, and the blobs expand to a larger major radius under the influence of a vertical electric field. The electric field, which is caused by {nabla}B and curvature drifts in a 1/R magnetic field, is limited by collisional damping on the neutral gas. The blob's electrostatic potential structure and the resulting ExB flow field give rise to a vortex pair and a mushroom shape, which are consistent with nonlinear plasma simulations. We observe experimentally this characteristic mushroom shape for the first time. We also find that the blob propagation velocity is inversely proportional to the neutral density and decreases with time as the blob cools.

Katz, Noam; Egedal, Jan; Fox, Will; Le, Ari; Porkolab, Miklos [Department of Physics/Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2008-07-04

472

Ionic wave propagation along actin filaments.  

PubMed

We investigate the conditions enabling actin filaments to act as electrical transmission lines for ion flows along their lengths. We propose a model in which each actin monomer is an electric element with a capacitive, inductive, and resistive property due to the molecular structure of the actin filament and viscosity of the solution. Based on Kirchhoff's laws taken in the continuum limit, a nonlinear partial differential equation is derived for the propagation of ionic waves. We solve this equation in two different regimes. In the first, the maximum propagation velocity wave is found in terms of Jacobi elliptic functions. In the general case, we analyze the equation in terms of Fisher-Kolmogoroff modes with both localized and extended wave characteristics. We propose a new signaling mechanism in the cell, especially in neurons. PMID:15041636

Tuszy?ski, J A; Portet, S; Dixon, J M; Luxford, C; Cantiello, H F

2004-04-01

473

BRITISH MOLDING MACHINE, PBQ AUTOMATIC COPE AND DRAG MOLDING MACHINE ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

BRITISH MOLDING MACHINE, PBQ AUTOMATIC COPE AND DRAG MOLDING MACHINE MAKES BOTH MOLD HALVES INDIVIDUALLY WHICH ARE LATER ROTATED, ASSEMBLED, AND LOWERED TO POURING CONVEYORS BY ASSISTING MACHINES. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

474

14. Interior, Machine Shop, Roundhouse Machine Shop Extension, Southern Pacific ...  

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. Interior, Machine Shop, Roundhouse Machine Shop Extension, Southern Pacific Railroad Carlin Shops, view to north (90mm lens). - Southern Pacific Railroad, Carlin Shops, Roundhouse Machine Shop Extension, Foot of Sixth Street, Carlin, Elko County, NV

475

High-Speed Machining of Materials with Low Machinability.  

National Technical Information Service (NTIS)

Materials with low machinability are often characterized by the difficulty of machining them by almost any cutting method. However, nowadays there are some advanced cutting methods and cutting tool materials available to make their machining possible. Cla...

J. Paro I. Nieminen V. Kauppinen

1995-01-01

476

Energetic particle evidence for magnetic filaments in Jupiter's magnetotail  

NASA Astrophysics Data System (ADS)

Jupiter's immense magnetotail was uniquely traversed and observed in situ to 2562 Jovian radii (RJ = 71,492 km) for the first time by the Pluto-bound New Horizons spacecraft during the first half of 2007. We show evidence that energetic ions with sulfur-rich composition traceable to Io's volcanism originated 150 ± 40 RJ antisunward of the planet and were recurrently released and funneled by the magnetic field down the magnetotail. Ions detected at New Horizons by the Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) instrument showed unmistakable signatures of velocity dispersion. We performed a survey of the unambiguous dispersion events observed by PEPSSI and provide a quantitative description of each event's dispersion characteristics. Energetic ions are sensitive probes of the magnetic field structure in the magnetotail; so, for a case study of one of the most interesting events, beginning on day of year 118, 28 April 2007, we are also able to estimate small-scale features of the magnetotail. Our observations (which include energies above ˜2 keV/nuc and total energies below ˜1 MeV), combined with straightforward simulations of particle flow, are consistent with narrow spatial structures, or filaments, on the order of 5 RJ wide in the ˜400 RJ wide > 9000 RJ long magnetotail; the Solar Wind Around Pluto plasma instrument measurements show coherent structures on a much larger scale (˜500 RJ) in the same region.

Hill, Matthew E.; Haggerty, Dennis K.; McNutt, Ralph L.; Paranicas, Christopher P.

2009-11-01

477

Effective medium theory of semiflexible filamentous networks.  

PubMed

We develop an effective medium approach to the mechanics of disordered, semiflexible polymer networks and study the response of such networks to uniform and nonuniform strain. We identify distinct elastic regimes in which the contributions of either filament bending or stretching to the macroscopic modulus vanish. We also show that our effective medium theory predicts a crossover between affine and nonaffine strain, consistent with both prior numerical studies and scaling theory. PMID:17678331

Das, Moumita; MacKintosh, F C; Levine, Alex J

2007-07-18

478

A Theoretical Approach to Actin Filament Dynamics  

Microsoft Academic Search

Dynamic control of the actin network in eukaryotic cells plays an essential role in their movement, but to date our understanding\\u000a of how the network properties are controlled in space and time is still rudimentary. For example, how the cell maintains the\\u000a pools of monomeric actin needed for a rapid response to signals, how the filament length distribution is controlled,

Jifeng Hu; Anastasios Matzavinos; Hans G. Othmer

2007-01-01

479

The properties of galaxies in supercluster filaments  

NASA Astrophysics Data System (ADS)

Superclusters appear as large-scale structures in the form of a network of filaments, and can be up to 100h-1100 Mpc in extent. In this dissertation, we investigate in detail the spatial structure of the three richest superclusters of galaxies closer to us then z=0.1. We investigate the rate of star formation in galaxies at various positions among the filaments and clusters in the Pisces-Cetus Supercluster. We use an index of star formation derived from a principal component analysis of optical spectral. We have shown that galaxies which are members of these filaments, show a steady decline in star formation rate, from the periphery of a cluster, into the cluster core. However, on top of this trend, we find a nearby instantaneous enhancement of the rate of star formation at ~3h-170 Mpc from its centre. We conclude that the most likely reason for this sudden enhancement in star formation rate is galaxy-galaxy harassment. Further work shows that the enhancement in star formation occurs mainly in the in falling dwarf galaxies (-20 < MB < -17.5) and that there is little evidence that the tidal effect of the dark matter haloes of the clusters is responsible for the enhanced star formation. The results of an analysis performed on a larger ensemble of 52 filaments were consistent with those from our smaller sample drawn from the Pisces-Cetus supercluster. We conclude this study with the analysis of a sample of spectra from the 6dF redshift survey. In the absence of spectrophotometric calibration, for these galaxies we were only able to obtain an uncalibrated star formation rate, but we could examine the effect of correction due to dust extinction, and could separate the starforming galaxies from the active galactic nuclei. From our small sample, there was interesting evidence of enhanced star formation in galaxies at similar distances from the centres of the clusters in the Shapley Supercluster.

Porter, Scott C.

2007-10-01

480

Gasification behavior of catalytic filamentous carbon  

Microsoft Academic Search

The paper reports on the effect of the catalytic filamentous carbon (CFC) gasification on its textural properties. CFC samples were prepared by methane decomposition over metal catalysts (Ni, Co, Ni–Cu, Fe–Co-alumina) at 500–625 °C. With respect to the ease of hydrogasification, CFC samples of different types can be arranged in the following order: CFC (Co)>CFC (Fe–Co)=CFC (Ni)?CFC (Ni–Cu, 575 °C).

L. B. Avdeeva; T. V. Reshetenko; V. B. Fenelonov; A. L. Chuvilin; Z. R. Ismagilov

2004-01-01

481

Molecular Phylogeny of Metazoan Intermediate Filament Proteins  

Microsoft Academic Search

.   We have cloned cytoplasmic intermediate filament (IF) proteins from a large number of invertebrate phyla using cDNA probes,\\u000a the monoclonal antibody IFA, peptide sequence information, and various RT-PCR procedures. Novel IF protein sequences reported\\u000a here include the urochordata and nine protostomic phyla, i.e., Annelida, Brachiopoda, Chaetognatha, Echiura, Nematomorpha,\\u000a Nemertea, Platyhelminthes, Phoronida, and Sipuncula. Taken together with the wealth of

Andreas Erber; Dieter Riemer; Marc Bovenschulte; Klaus Weber

1998-01-01

482

The evolving structure of an upwelling filament  

Microsoft Academic Search

The evolution of an upwelling filament was studied over a 2-week period by using satellite infrared images, and its thermohaline structure was mapped in situ. The surface velocity field consisted of a large meander extending offshore for at least 300 km. The northern branch was ~40 km wide, flowing offshore at a peak velocity of 0.55 m\\/s; the southern branch

Pierre Flament; Laurence Armi; Libe Washburn

1985-01-01

483

Machine vision metal inspection  

NASA Astrophysics Data System (ADS)

A new procedure is presented to introduce machine vision into a rolling mill environment for real-time on-line metal bar and rod inspection for flaw detection and characterization. Results are presented relating machine vision metal flaw signatures to flaw type and characteristics.

Morris, John W.; Notarangelo, Joseph

1994-03-01

484

Biological Molecular Machines  

NASA Astrophysics Data System (ADS)

Like small molecules taking part in usual chemical reactions, biological molecular machines perform their functions owing to thermal fluctuations and the only difference consists in more complex and specially organized internal dynamics. It is this dynamics that determines processes of free energy transduction in molecular machines. The case of the actomyosin motor is considered in some detail.

Kurzy?ski, Micha?

2007-11-01

485

Relational Temporal Machines  

Microsoft Academic Search

The paper introduces and investigates relational temporal machine (RTM) as a general abstract model for generic temporal querying. The RTM devices subsume most temporal query languages that have emerged in the literature. A first contribution of the paper is to provide two simplified forms for our machines, namely extended one- tape RTMS and one-tape RTMS. Another contribution is to establish

Nicole Bidoit; Francois Hantry

2007-01-01

486

Why Machine Ethics?  

Microsoft Academic Search

Machine ethics isn't merely science fiction; it's a topic that requires serious consideration, given the rapid emergence of increasingly complex autonomous software agents and robots. Machine ethics is an emerging field that seeks to implement moral decision-making faculties in computers and robots. We already have semiautonomous robots and software agents that violate ethical standards as a matter of course. In

Colin Allen; Wendell Wallach; Iva Smit

2006-01-01

487

The Chemical Abstract Machine  

Microsoft Academic Search

We introduce a new kind of abstract machine based on the chemical metaphor used in the ? language of Banâtre & al. States of a machine are chemical solutions where floating molecules can interact according to reaction rules. Solutions can be stratified by encapsulating subsolutions within membranes that force reactions to occur locally. We illustrate the use of this model

Gérard Berry; Gérard Boudol

1990-01-01

488

Simple Machine Junk Cars  

ERIC Educational Resources Information Center

|During the month of May, the author's eighth-grade physical science students study the six simple machines through hands-on activities, reading assignments, videos, and notes. At the end of the month, they can easily identify the six types of simple machine: inclined plane, wheel and axle, pulley, screw, wedge, and lever. To conclude this unit,…

Herald, Christine

2010-01-01

489

Wave Machine Model  

NSDL National Science Digital Library

The Wave Machine model simulates the wave machine produced by John Shive at Bell Laboratories and made famous by the PSSC Simple Waves film. The machine consists of horizontal bars welded to a torsion rod that is perpendicular to the bars. The simulation allows the user to change the lengths of the bars, thereby simulating the effect of a wave propagating in a non-uniform medium. The simulation allows various pulse shapes to be sent down the machine by selecting a function for the twist of the first rod or by dragging the first rod. For example, applying a Gaussian twist produces a Gaussian traveling pulse but the width of this pulse depends on the wave speed. The far end of the wave machine can be free or clamped and this changes the nature of the reflected wave. The Wave Machine model is a supplemental simulation for the article "Standing Waves in a Nonuniform Medium" by Paul Gluck in The Physics Teacher 49(2), 76-77 (2011) and has been approved by the authors and The Physics Teacher editor. The Wave Machine 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_mech_osc_chains_WaveMachine.jar file will run the program if Java is installed.

Christian, Wolfgang

2010-11-07

490

Support vector machines  

Microsoft Academic Search

My first exposure to Support Vector Machines came this spring when heard Sue Dumais present impressive results on text categorization using this analysis technique. This issue's collection of essays should help familiarize our readers with this interesting new racehorse in the Machine Learning stable. Bernhard Scholkopf, in an introductory overview, points out that a particular advantage of SVMs over other

M. A. Hearst; S. T. Dumais; E. Osman; J. Platt; B. Scholkopf

1998-01-01

491

Stirling machine operating experience  

SciTech Connect

Numerous Stirling machines have been built and operated, but the operating experience of these machines is not well known. It is important to examine this operating experience in detail, because it largely substantiates the claim that stirling machines are capable of reliable and lengthy operating lives. The amount of data that exists is impressive, considering that many of the machines that have been built are developmental machines intended to show proof of concept, and are not expected to operate for lengthy periods of time. Some Stirling machines (typically free-piston machines) achieve long life through non-contact bearings, while other Stirling machines (typically kinematic) have achieved long operating lives through regular seal and bearing replacements. In addition to engine and system testing, life testing of critical components is also considered. The record in this paper is not complete, due to the reluctance of some organizations to release operational data and because several organizations were not contacted. The authors intend to repeat this assessment in three years, hoping for even greater participation.

Ross, B. [Stirling Technology Co., Richland, WA (United States); Dudenhoefer, J.E. [Lewis Research Center, Cleveland, OH (United States)

1994-09-01

492

Imagining machines with imagination  

Microsoft Academic Search

The author reviews and comments upon George Morton's predictive paper “Machines with Imagination”. He argues that Morton's paper demonstrates a significant insight into the progress of machine intelligence, particularly because that progress was hardly accomplished in a linear progression of systematic advances. Indeed, the forecasts laid down in Morton's paper have become pertinent only after a series of relative failures

DAVID B. FOGEL

2000-01-01

493

A 34-meter VAWT (Vertical Axis Wind Turbine) point design  

NASA Astrophysics Data System (ADS)

The Wind Energy Division at Sandia National Laboratories recently completed a point design based on the 34-m Vertical Axis Wind Turbine (VAWT) Test Bed. The 34-m Test Bed research machine incorporates several innovations that improve Darrieus technology, including increased energy production, over previous machines. The point design differs minimally from the Test Bed; but by removing research-related items, its estimated cost is substantially reduced. The point design is a first step towards a Test-Bed-based commercial machine that would be competitive with conventional sources of power in the mid-1990s.

Ashwill, T. D.; Berg, D. E.; Dodd, H. M.; Rumsey, M. A.; Sutherland, H. J.; Veers, P. S.

494

A 34-meter VAWT (Vertical Axis Wind Turbine) point design  

SciTech Connect

The Wind Energy Division at Sandia National Laboratories recently completed a point design based on the 34-m Vertical Axis Wind Turbine (VAWT) Test Bed. The 34-m Test Bed research machine incorporates several innovations that improve Darrieus technology, including increased energy production, over previous machines. The point design differs minimally from the Test Bed; but by removing research-related items, its estimated cost is substantially reduced. The point design is a first step towards a Test-Bed-based commercial machine that would be competitive with conventional sources of power in the mid-1990s. 11 refs., 12 figs., 4 tabs.

Ashwill, T.D.; Berg, D.E.; Dodd, H.M.; Rumsey, M.A.; Sutherland, H.J.; Veers, P.S.

1991-01-01

495

The Magnetic Structure of Filament Barbs  

NASA Astrophysics Data System (ADS)

There is a controversy about how features protruding laterally from filaments, called barbs, are magnetically structured. On 2004 August 3, we observed a filament that had well-developed barbs. The observations were performed using the 10 inch refractor of the Big Bear Solar Observatory. A fast camera was employed to capture images at five different wavelengths of the H? line and successively record them on the basis of frame selection. The terminating points of the barbs were clearly discernable in the H? images without any ambiguity. The comparison of the H? images with the magnetograms taken by SOHO MDI revealed that the termination occurred above the minor polarity inversion line dividing the magnetic elements of the major polarity and those of the minor polarity. There is also evidence that the flux cancellation proceeded on the polarity inversion line. Our results together with similar other recent observations support the idea that filament barbs are cool matter suspended in local dips of magnetic field lines, formed by magnetic reconnection in the chromosphere.

Chae, Jongchul; Moon, Yong-Jae; Park, Young-Deuk

2005-06-01

496

Controlled Filament Non-Local Discharge (CFND) .  

NASA Astrophysics Data System (ADS)

Recently there has been increased interest in methods to achieve non-local electron effects to tailor the electron energy distribution (EED) for special applications like singlet delta oxygen (SDO) generation. However, a way to favor SDO production ( requires an E/N ˜ 10 Td = 10-16 Vcm^2) while still having a high pressure and large volume has not been achieved. Here we present an innovative new concept -- the controlled filament non-local discharge (CFND) in an effort to overcome these shortcomings. The CFND uses micro protrusions on the cathode surface to produce a multi-filament breakdown. The filaments create highly non-equilibrium beam-like electrons embedded in the background plasma discharge, providing control over the volume E/N. The micro-projection cathode design will be discussed and is the key to achieving the CFND. The high electric fields at the projection tips imitate micro arc discharges, enabling discharge breakdown with a relatively low applied voltage despite a high pressure. Once initiated, the discharge voltage drops as a non-local discharge develops over the volume. It is estimated that after initial breakdown at 600 V, an E/N of 10-16 Vcm^2 is obtained at roughly atmospheric pressure in oxygen with an applied voltage of 100 V in planar electrode geometry at a spacing of 10 cm.

Miley, George H.

2006-10-01

497

Experimental Study of the Current Filamentation Instability  

NASA Astrophysics Data System (ADS)

The Current Filamentation Instability (CFI) is of central importance for the propagation of relativistic electron beams in plasmas. CFI has potential relevance to astrophysics, afterglow of gamma ray bursts, inertial confinement fusion, energy transport in the fast-igniter concept, and places an upper limit on the plasma density and accelerating gradient in PWFA's. An experimental study at the Accelerator Test Facility at Brookhaven National Laboratory with the 60MeV e^- beam and cm length plasma. The experiment included the systematic study and characterization of the instability as a function of the beam charge and plasma density. The transverse beam profile is measured directly at the plasma exit using OTR. Experimental results show the transition from plasma focusing to CFI near kp?r=1 characterized by the appearance of multiple (1-5) beam filaments and scaling of the transverse filament size with the plasma skin depth. Suppression of the instability is seen by lowering the growth rate of the instability by reducing the beam charge. The experimental results are in excellent agreement with theory and simulations and we present and discuss simulation and experimental results.

Allen, Brian; Muggli, Patric; Silva, Luis O.; Martins, Joana; Yakimenko, Vitaly; Fedurin, Mikhail; Kusche, Karl; Babzien, Marcus; Huang, Chengkun; Mori, Warren

2012-10-01

498

Elasticity of a filamentous kagome lattice  

NASA Astrophysics Data System (ADS)

The diluted kagome lattice, in which bonds are randomly removed with probability 1-p, consists of straight lines that intersect at points with a maximum coordination number of 4. If lines are treated as semiflexible polymers and crossing points are treated as cross-links, this lattice provides a simple model for two-dimensional filamentous networks. Lattice-based effective-medium theories and numerical simulations for filaments modeled as elastic rods, with stretching modulus ? and bending modulus ?, are used to study the elasticity of this lattice as functions of p and ?. At p=1, elastic response is purely affine, and the macroscopic elastic modulus G is independent of ?. When ?=0, the lattice undergoes a first-order rigidity-percolation transition at p=1. When ?>0, G decreases continuously as p decreases below one, reaching zero at a continuous rigidity-percolation transition at p=pb?0.605 that is the same for all nonzero values of ?. The effective-medium theories predict scaling forms for G, which exhibit crossover from bending-dominated response at small ?/? to stretching-dominated response at large ?/? near both p=1 and pb, that match simulations with no adjustable parameters near p=1. The affine response as p?1 is identified with the approach to a state with sample-crossing straight filaments treated as elastic rods.

Mao, Xiaoming; Stenull, Olaf; Lubensky, T. C.

2013-04-01

499

Dynamics of the neuronal intermediate filaments  

PubMed Central

We have analyzed the dynamics of neuronal intermediate filaments in living neurons by using the method of photobleaching of fluorescently- labeled neurofilament L protein and immunoelectron microscopy of incorporation sites of biotinylated neurofilament L protein. Low-light- level imaging and photobleaching of growing axons of mouse sensory neurons did not affect the rate of either axonal growth or the addition of intermediate filament structures at the axon terminal, suggesting that any perturbations caused by these optical methods would be minimal. After laser photobleaching, recovery of fluorescence did occur slowly with a recovery half-time of 40 min. Furthermore, we observed a more rapid fluorescence recovery in growing axons than in quiescent ones, indicating a growth-dependent regulation of the turnover rate. Incorporation sites of biotin-labeled neurofilament L protein were localized as numerous discrete sites along the axon, and they slowly elongated to become continuous arrays 24 h after injection. Collectively, these results indicate that neuronal intermediate filaments in growing axons turn over within the small area of the axoplasm possibly by the mechanism of lateral and segmental incorporation of new subunits.

1993-01-01

500

Hot filament CVD of boron nitride films  

DOEpatents

Using a hot filament (.apprxeq.1400.degree. C.) to activate borazine (B.sub.3 N.sub.3 H.sub.6) molecules for subsequent reaction with a direct line-of-sight substrate, transparent boron ntiride films as thick as 25,000 angstroms are grown for a substrate temperature as low as 100.degree. C. The minimum temperature is determined by radiative heating from the adjacent hot filament. The low temperature BN films show no indication of crystallinity with X-ray diffraction (XRD). X-ray photoelectron spectra (XPS) show the films to have a B:N ratio of 0.97:1 with no other XPS detectable impurities above the 0.5% level. Both Raman and infrared (IR) spectroscopy are characteristic of h-BN with small amounts of hydrogen detected as N-H and B-H bands in the IR spectrum. An important feature of this method is the separation and localization of the thermal activation step at the hot filament from the surface reaction and film growth steps at the substrate surface. This allows both higher temperature thermal activation and lower temperature film growth.

Rye, Robert R. (Albuquerque, NM)

1992-01-01