A multi-slot surface coil for MRI of dual-rat imaging at 4 T

International Nuclear Information System (INIS)

Solis, S E; Rodriguez, A O; Wang, R; Tomasi, D

2011-01-01

A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

A multi-slot surface coil for MRI of dual-rat imaging at 4T

Energy Technology Data Exchange (ETDEWEB)

Solis, S.E.; Tomasi, D.; Solis, S.E.; Wang, R.; Tomasi, D.; Rodriguez, A.O.

2011-07-01

A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

A multi-slot surface coil for MRI of dual-rat imaging at 4 T

Energy Technology Data Exchange (ETDEWEB)

Solis, S E; Rodriguez, A O [Departamento de Ingenieria Electrica, Universidad Autonoma Metropolitana Iztapalapa, Mexico, DF 09340 (Mexico); Wang, R; Tomasi, D, E-mail: arog@xanum.uam.mx [Medical Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2011-06-21

A slotted surface coil inspired by the hole-and-slot cavity magnetron was developed for magnetic resonance imaging of obese rats at 4 T. Full-wave analysis of the magnetic field was carried out at 170 MHz for both the slotted and circular-shaped coils. The noise figure values of two coils were investigated via the numerical calculation of the quality factors. Fat simulated phantoms to mimic overweight rats were included in the analysis with weights ranging from 300 to 900 g. The noise figures were 1.2 dB for the slotted coil and 2.4 dB for the circular coil when loaded with 600 g of simulated phantom. A slotted surface coil with eight circular slots and a circular coil with similar dimensions were built and operated in the transceiver mode, and their performances were experimentally compared. The imaging tests in phantoms demonstrated that the slotted surface coil has a deeper RF-sensitivity and better field uniformity than the single-loop RF-coil. High quality images of two overweight Zucker rats were acquired simultaneously with the slotted surface coil using standard spin-echo pulse sequences. Experimental results showed that the slotted surface coil outperformed the circular coil for imaging considerably overweight rats. Thus, the slotted surface coil can be a good tool for MRI experiments in rats on a human whole-body 4 T scanner.

Eddy current loss analysis of open-slot fault-tolerant permanent-magnet machines based on conformal mapping method

Science.gov (United States)

Ji, Jinghua; Luo, Jianhua; Lei, Qian; Bian, Fangfang

2017-05-01

This paper proposed an analytical method, based on conformal mapping (CM) method, for the accurate evaluation of magnetic field and eddy current (EC) loss in fault-tolerant permanent-magnet (FTPM) machines. The aim of modulation function, applied in CM method, is to change the open-slot structure into fully closed-slot structure, whose air-gap flux density is easy to calculate analytically. Therefore, with the help of Matlab Schwarz-Christoffel (SC) Toolbox, both the magnetic flux density and EC density of FTPM machine are obtained accurately. Finally, time-stepped transient finite-element method (FEM) is used to verify the theoretical analysis, showing that the proposed method is able to predict the magnetic flux density and EC loss precisely.

Effect of pole number and slot number on performance of dual rotor permanent magnet wind power generator using ferrite magnets

Directory of Open Access Journals (Sweden)

Peifeng Xu

2017-05-01

Full Text Available Dual rotor permanent magnet (DRPM wind power generator using ferrite magnets has the advantages of low cost, high efficiency, and high torque density. How to further improve the performance and reduce the cost of the machine by proper choice of pole number and slot number is an important problem to be solved when performing preliminarily design a DRPM wind generator. This paper presents a comprehensive performance comparison of a DRPM wind generator using ferrite magnets with different slot and pole number combinations. The main winding factors are calculated by means of the star of slots. Under the same machine volume and ferrite consumption, the flux linkage, back-electromotive force (EMF, cogging torque, output torque, torque pulsation, and losses are investigated and compared using finite element analysis (FEA. The results show that the slot and pole number combinations have an important impact on the generator properties.

Rotor for a line start permanent magnet machine

Science.gov (United States)

Melfi, Mike; Schiferl, Rich; Umans, Stephen

2017-07-11

A rotor comprises laminations with a plurality of rotor bar slots with an asymmetric arrangement about the rotor. The laminations also have magnet slots equiangularly spaced about the rotor. The magnet slots extend near to the rotor outer diameter and have permanent magnets disposed in the magnet slots creating magnetic poles. The magnet slots may be formed longer than the permanent magnets disposed in the magnets slots and define one or more magnet slot apertures. The permanent magnets define a number of poles and a pole pitch. The rotor bar slots are spaced from adjacent magnet slots by a distance that is at least 4% of the pole pitch. Conductive material is disposed in the rotor bar slots, and in some embodiments, may be disposed in the magnet slot apertures.

Investigation of a less rare-earth permanent-magnet machine with the consequent pole rotor

Science.gov (United States)

Bai, Jingang; Liu, Jiaqi; Wang, Mingqiao; Zheng, Ping; Liu, Yong; Gao, Haibo; Xiao, Lijun

2018-05-01

Due to the rising price of rare-earth materials, permanent-magnet (PM) machines in different applications have a trend of reducing the use of rare-earth materials. Since iron-core poles replace half of PM poles in the consequent pole (CP) rotor, the PM machine with CP rotor can be a promising candidate for less rare-earth PM machine. Additionally, the investigation of CP rotor in special electrical machines, like hybrid excitation permanent-magnet PM machine, bearingless motor, etc., has verified the application feasibility of CP rotor. Therefore, this paper focuses on design and performance of PM machines when traditional PM machine uses the CP rotor. In the CP rotor, all the PMs are of the same polarity and they are inserted into the rotor core. Since the fundamental PM flux density depends on the ratio of PM pole to iron-core pole, the combination rule between them is investigated by analytical and finite-element methods. On this basis, to comprehensively analyze and evaluate PM machine with CP rotor, four typical schemes, i.e., integer-slot machines with CP rotor and surface-mounted PM (SPM) rotor, fractional-slot machines with CP rotor and SPM rotor, are designed to investigate the performance of PM machine with CP rotor, including electromagnetic performance, anti-demagnetization capacity and cost.

Precise Alignment and Permanent Mounting of Thin and Lightweight X-ray Segments

Science.gov (United States)

Biskach, Michael P.; Chan, Kai-Wing; Hong, Melinda N.; Mazzarella, James R.; McClelland, Ryan S.; Norman, Michael J.; Saha, Timo T.; Zhang, William W.

2012-01-01

To provide observations to support current research efforts in high energy astrophysics. future X-ray telescope designs must provide matching or better angular resolution while significantly increasing the total collecting area. In such a design the permanent mounting of thin and lightweight segments is critical to the overall performance of the complete X-ray optic assembly. The thin and lightweight segments used in the assemhly of the modules are desigued to maintain and/or exceed the resolution of existing X-ray telescopes while providing a substantial increase in collecting area. Such thin and delicate X-ray segments are easily distorted and yet must be aligned to the arcsecond level and retain accurate alignment for many years. The Next Generation X-ray Optic (NGXO) group at NASA Goddard Space Flight Center has designed, assembled. and implemented new hardware and procedures mth the short term goal of aligning three pairs of X-ray segments in a technology demonstration module while maintaining 10 arcsec alignment through environmental testing as part of the eventual design and construction of a full sized module capable of housing hundreds of X-ray segments. The recent attempts at multiple segment pair alignment and permanent mounting is described along with an overview of the procedure used. A look into what the next year mll bring for the alignment and permanent segment mounting effort illustrates some of the challenges left to overcome before an attempt to populate a full sized module can begin.

Evaluation of surface roughness of the bracket slot floor—a 3D perspective study

Directory of Open Access Journals (Sweden)

Chetankumar O. Agarwal

2016-01-01

Full Text Available Abstract Background An important constituent of an orthodontic appliance is orthodontic brackets. It is either the bracket or the archwire that slides through the bracket slot, during sliding mechanics. Overcoming the friction between the two surfaces demands an important consideration in an appliance design. The present study investigated the surface roughness of four different commercially available stainless steel brackets. Methods All tests were carried out to analyse quantitatively the morphological surface of the bracket slot floor with the help of scanning electron microscope (SEM machine and to qualitatively analyse the average surface roughness (Sa of the bracket slot floor with the help of a three-dimensional (3D non-contact optical surface profilometer machine. Results The SEM microphotographs were evaluated with the help of visual analogue scale, the surface roughness for group A = 0—very rough surface, group C = 1—rough surface, group B = 2—smooth surface, and group D = 3—very smooth surface. Surface roughness evaluation with the 3D non-contact optical surface profilometer machine was highest for group A, followed by group C, group B and group D. Groups B and D provided smooth surface roughness; however, group D had the very smooth surface with values 0.74 and 0.75 for mesial and distal slots, respectively. Conclusions Evaluation of surface roughness of the bracket slot floor with both SEM and profilometer machine led to the conclusion that the average surface roughness was highest for group A, followed by group C, group B and group D.

Influence of Closed Stator Slots on Cogging Torque

DEFF Research Database (Denmark)

Ion, Trifu; Leban, Krisztina Monika; Ritchie, Ewen

2013-01-01

Cogging torque results due interaction of magnetic field of magnets and stator slots, and have negative effects on permanent magnet machines such as vibrations, noise, torque ripples and problems during turbine start-up and cut-in. In order to reduce cogging torque this paper presents a study...... of influence of closed stator slots on cogging torque using magnetic slot wedges....

Comparing of cogging torque reduction methods in permanent magnet machines with fractional slot windings

Science.gov (United States)

Pristup, A. G.; Toporkov, D. M.

2017-10-01

The results of the investigation of the cogging torque in permanent magnet synchronous machines, which is caused by the stator slotting and the rotor eccentricity, are presented in the paper. A new design of the machine has been developed in the course of the investigation, and the value of the cogging torque in this construction is less considerably compared to other constructions. In contrast to the available methods of the cogging torque reduction, the solution suggested not only decreases the level of the cogging torque but also has negligibly small influence on characteristics of the machine with the rotor eccentricity which is typical of the mass production and long-term usage.

Method and apparatus for assembling permanent magnet rotors

Science.gov (United States)

Hsu, J.S.; Adams, D.J.

1999-06-22

A permanent magnet assembly for assembly in large permanent magnet motors and generators includes a two-piece carrier that can be slid into a slot in the rotor and then secured in place using a set screw. The invention also provides an auxiliary carrier device with guide rails that line up with the teeth of the rotor, so that a permanent magnet assembly can be pushed first into a slot, and then down the slot to its proper location. An auxiliary tool is provided to move the permanent magnet assembly into position in the slot before it is secured in place. Methods of assembling and disassembling the magnet assemblies in the rotor are also disclosed. 2 figs.

Effect of magnet/slot combination on triple-frequency magnetic force and vibration of permanent magnet motors

Science.gov (United States)

Huo, Mina; Wang, Shiyu; Xiu, Jie; Cao, Shuqian

2013-10-01

The relationship between magnet/slot combination and magnetic forces including unbalanced magnetic force (UMF) and cogging torque (CT) of permanent magnet (PM) motors is investigated by using superposition principle and mechanical and magnetic symmetries. The results show that magnetic force can be produced by all magnets passing a single slot, by all slots passing a single magnet, or by eccentricity, which respectively correspond to three frequency components. The results further show that net force/torque can be classified into three typical cases: UMF is suppressed and CT is excited, UMF excited and CT suppressed, and UMF and CT both suppressed, and consequently possible vibrations include three unique groups: rotational modes, translational modes, and balanced modes. The conclusion that combinations with the greatest common divisor (GCD) greater than unity can avoid UMF is mathematically verified, and at the same time lower CT harmonics are preliminarily addressed by the typical excitations. The above findings can create simple guidelines for the suppression of certain UMF and/or CT by using suitable combinations, which in turn can present approach to yield a more desirable response in high performance applications. The superposition effect and predicted relationship are verified by the transient magnetic Finite Element method. Since this work is motivated by symmetries, comparisons are made in order to give further insight into the inner force and vibration behaviors of general rotary power-transmission systems.

FLOW VISUALIZATION OF RECTANGULAR SLOT AIR JET IMPINGEMENT ON FLAT SURFACES

OpenAIRE

Satheesha V *1, B. K. Muralidhra2, Abhilash N3, C. K. Umesh4

2018-01-01

Jet impingement near the mid-chord of the gas turbine blade is treated as a flat plate. Experimental and numerical investigations are carried out for a single slot air jet impinging on flat surface for two different rectangular slots of dimension (3mm x 65 mm) and (5mm x 65 mm). Experimentation is done to study the flow pattern topography on the flat target plate, with varying the flow rate from 20 LPM to 50 LPM by varying the nozzle to plate distance from 9 mm to 24 mm for slot jet of 3mm an...

Mongolian Rotifers on Micr oscope Slides: Instructions to Permanent Specimen Mounts from Expedition Material

OpenAIRE

Christian D. Jersabek; Erdene Bolortsetseg; Howard L. Taylor

2010-01-01

We here describe a method for permanently mounting specimens on microscope slides, as we applied it in the newly established rotifer collection in Ulaanbaatar, Mongolia. The liquid photopolymer NOA 61 was used as a primary sealant for pure glycerine mounts. We furthermore outline simple methods of rotifer narcotization and fi xation in the fi eld that yield, for the majority of species, adequately preserved specimen mat...

Comparison of stator-mounted permanent-magnet machines based on a general power equation

DEFF Research Database (Denmark)

Chen, Zhe; Hua, Wei; Cheng, Ming

2009-01-01

The stator-mounted permanent-magnet (SMPM) machines have some advantages compared with its counterparts, such as simple rotor, short winding terminals, and good thermal dissipation conditions for magnets. In this paper, a general power equation for three types of SMPM machine is introduced first...

Development of a Double Glass Mounting Method Using Formaldehyde Alcohol Azocarmine Lactophenol (FAAL) and its Evaluation for Permanent Mounting of Small Nematodes.

Science.gov (United States)

Zahabiun, Farzaneh; Sadjjadi, Seyed Mahmoud; Esfandiari, Farideh

2015-01-01

Permanent slide preparation of nematodes especially small ones is time consuming, difficult and they become scarious margins. Regarding this problem, a modified double glass mounting method was developed and compared with classic method. A total of 209 nematode samples from human and animal origin were fixed and stained with Formaldehyde Alcohol Azocarmine Lactophenol (FAAL) followed by double glass mounting and classic dehydration method using Canada balsam as their mounting media. The slides were evaluated in different dates and times, more than four years. Different photos were made with different magnification during the evaluation time. The double glass mounting method was stable during this time and comparable with classic method. There were no changes in morphologic structures of nematodes using double glass mounting method with well-defined and clear differentiation between different organs of nematodes in this method. Using this method is cost effective and fast for mounting of small nematodes comparing to classic method.

Reluctance network modelling of surface permanent magnet motor considering iron nonlinearities

International Nuclear Information System (INIS)

Raminosoa, T.; Farooq, J.A.; Djerdir, A.; Miraoui, A.

2009-01-01

This paper presents a simple, quick and precise nonlinear reluctance network modelling of an in-wheel surface permanent magnet motor. The saturation of the ferromagnetic materials is considered and a simple air-gap length function is used to take the slotting effect into account. The topology and the reluctance values of the air-gap network are automatically computed for any rotor position. Thus, the proposed technique allows a steady state time stepping simulation. For any saturation level, there is a good accordance with the finite element method for the torque and back EMF. Moreover, the model accurately predicts the effect of the demagnetization. The proposed model can be advantageously used for a geometry optimization as well as for the diagnosis of demagnetization.

Cogging Torque Reduction by Slot-Opening Shift for Permanent Magnet Machines

DEFF Research Database (Denmark)

Liu, Ting; Huang, Shoudao; Gao, Jian

2013-01-01

In this paper, an effective cogging torque reduction method based on shifting the slot-openings is presented. Stator teeth are divided into groups and proper slot-opening shift is applied for each group. The cogging torque can then be greatly reduced while the back-EMF waveforms remain symmetrical...

Modeling and Analysis of Double Stator Slotted Rotor Permanent Magnet Generator

Directory of Open Access Journals (Sweden)

Suhairi Rizuan Che Ahmad

2017-03-01

Full Text Available This paper discusses the modeling and analysis of three phase double stator slotted rotor permanent magnet generator (DSSR-PMG. The use of double stator topology through the double magnetic circuit helps to maximize the usage of flux linkage in the yoke structure of the single stator topology. The analytical computation is done using Permeance Analysis Method (PAM. Finite Element Analysis (FEA is used for numerical verifications and to verify the design structure a prototype laboratory is performed. The analysis is done with various loading conditions to derive the electromagnetic torque, output power and efficiency for the proposed structure. The analytical, numerical and experimental results from the analysis are found to be in good agreement. The maximum power developed by this generator at rated speed of 2000 rpm is of 1 kW with the operational efficiency of 75%. A rectifier bridge circuit is used to make the generated voltage a storage capable constant voltage to make it suitable for mobile applications (such as Direct Current DC generator. The proposed generator structure is highly recommended for applications such as micro-hydro and small renewable plants.

Wideband, Low-Profile, Dual-Polarized Slot Antenna with an AMC Surface for Wireless Communications

Directory of Open Access Journals (Sweden)

Wei Hu

2016-01-01

Full Text Available A wideband dual-polarized slot antenna loaded with artificial magnetic conductor (AMC is proposed for WLAN/WIMAX and LTE applications. The slot antenna mainly consists of two pairs of arrow-shaped slots along the diagonals of the square patch. Stepped microstrip feedlines are placed orthogonally to excite the horizontal and vertical polarizations of the antenna. To realize unidirectional radiation and low profile, an AMC surface composed of 7 × 7 unit cells is designed underneath a distance of 0.09λ0 (λ0 being the wavelength in free space at 2.25 GHz from the slot antenna. Both the dual-polarized slot antenna and the AMC surface are fabricated and measured. Experimental results demonstrate that the proposed antenna achieves for both polarizations a wide impedance bandwidth (return loss 10 dB of 36.7%, operating from 1.96 to 2.84 GHz. The isolation between the two input ports keeps higher than 29 dB whereas the cross-polarization levels basically maintain lower than −30 dB across the entire frequency band. High front-to-back ratios better than 22 dB and a stable gain higher than 8 dBi are obtained over the whole band.

An Experimental Study of a Sting-Mounted Circulation Control Wing

Science.gov (United States)

1991-12-01

atmospheric pressure was read from a Henry J. Green ML-330/FM mercury barometer and the desired tunnel q was determined from: q.)= 1/2 RTatms (21) F atmos C2...attachment to the Coanda surface. With the model mounted on a bench outside the tunnel, a fixture was attached to the model so that a pitot tube could be...mounted immediately aft of the blowing slot to measure jet total pressure at any point along the trailing edge. The pitot tube was connected to a 50 inch

Enhancement of acousto-optical coupling in two-dimensional air-slot phoxonic crystal cavities by utilizing surface acoustic waves

Energy Technology Data Exchange (ETDEWEB)

Ma, Tian-Xue [Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing 100044 (China); Wang, Yue-Sheng, E-mail: yswang@bjtu.edu.cn [Institute of Engineering Mechanics, Beijing Jiaotong University, Beijing 100044 (China); Zhang, Chuanzeng [Department of Civil Engineering, University of Siegen, D-57068 Siegen (Germany)

2017-01-30

A phoxonic crystal is a periodically patterned material that can simultaneously localize optical and acoustic modes. The acousto-optical coupling in two-dimensional air-slot phoxonic crystal cavities is investigated numerically. The photons can be well confined in the slot owing to the large electric field discontinuity at the air/dielectric interfaces. Besides, the surface acoustic modes lead to the localization of the phonons near the air-slot. The high overlap of the photonic and phononic cavity modes near the slot results in a significant enhancement of the moving interface effect, and thus strengthens the total acousto-optical interaction. The results of two cavities with different slot widths show that the coupling strength is dependent on the slot width. It is expected to achieve a strong acousto-optical/optomechanical coupling in air-slot phoxonic crystal structures by utilizing surface acoustic modes. - Highlights: • Two-dimensional air-slot phoxonic crystal cavities which can confine simultaneously optical and acoustic waves are proposed. • The acoustic and optical waves are highly confined near/in the air-slot. • The high overlap of the photonic and phononic cavity modes significantly enhances the moving interface effect. • Different factors which affect the acousto-optical coupling are discussed.

A design procedure for a slotted waveguide with probe-fed slots radiating into plasma

International Nuclear Information System (INIS)

Colborn, J.A.

1989-11-01

A design procedure is developed for slotted-waveguide antennas with probe-fed slots. Radiation into a gyrotropic, plane-stratified medium is considered, nonzero waveguide wall thickness is assumed, and noncosinusoidal slot fields and arbitrary slot length up to about one free-space wavelength are allowed. External mutual coupling is taken into account by matching the tangential fields at the antenna surface. The particular case of longitudinal slots in the broad face of rectangular guide is analyzed. The motivation for this work is the design of such radiators for plasma heating and current-drive on thermonuclear fusion experiments, but some of the analysis is applicable to the probeless slotted waveguide used for avionics and communications. 20 refs., 5 figs

Two-Slotted Surface Coil Array for Magnetic Resonance Imaging at 4 Tesla

International Nuclear Information System (INIS)

Solis, S. E.; Hernandez, J. A.; Rodriguez, A. O.; Tomasi, D.

2008-01-01

Arrays of antennas have been widely accepted for magnetic resonance imaging applications due to their high signal-to-noise ratio (SNR) over large volumes of interest. A new surface coil based on the magnetron tube and called slotted surface coil, has been recently introduced by our group. This coil design experimentally demonstrated a significant improvement over the circular-shaped coil when used in the receive-only mode. The slotted coils formed a two-sheet structure with a 90 deg. separation and each coil had 6 circular slots. Numerical simulations were performed using the finite element method for this coil design to study the behaviour of the array magnetic field. Then, we developed a two-coil array for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. In vitro images showed the feasibility of this coil array for standard pulses for high field magnetic resonance imaging

Optimal Design Solutions for Permanent Magnet Synchronous Machines

Directory of Open Access Journals (Sweden)

POPESCU, M.

2011-11-01

Full Text Available This paper presents optimal design solutions for reducing the cogging torque of permanent magnets synchronous machines. A first solution proposed in the paper consists in using closed stator slots that determines a nearly isotropic magnetic structure of the stator core, reducing the mutual attraction between permanent magnets and the slotted armature. To avoid complications in the windings manufacture technology the stator slots are closed using wedges made of soft magnetic composite materials. The second solution consists in properly choosing the combination of pole number and stator slots number that typically leads to a winding with fractional number of slots/pole/phase. The proposed measures for cogging torque reduction are analyzed by means of 2D/3D finite element models developed using the professional Flux software package. Numerical results are discussed and compared with experimental ones obtained by testing a PMSM prototype.

A Novel Method to Magnetic Flux Linkage Optimization of Direct-Driven Surface-Mounted Permanent Magnet Synchronous Generator Based on Nonlinear Dynamic Analysis

Directory of Open Access Journals (Sweden)

Qian Xie

2016-07-01

Full Text Available This paper pays attention to magnetic flux linkage optimization of a direct-driven surface-mounted permanent magnet synchronous generator (D-SPMSG. A new compact representation of the D-SPMSG nonlinear dynamic differential equations to reduce system parameters is established. Furthermore, the nonlinear dynamic characteristics of new D-SPMSG equations in the process of varying magnetic flux linkage are considered, which are illustrated by Lyapunov exponent spectrums, phase orbits, Poincaré maps, time waveforms and bifurcation diagrams, and the magnetic flux linkage stable region of D-SPMSG is acquired concurrently. Based on the above modeling and analyses, a novel method of magnetic flux linkage optimization is presented. In addition, a 2 MW D-SPMSG 2D/3D model is designed by ANSYS software according to the practical design requirements. Finally, five cases of D-SPMSG models with different magnetic flux linkages are simulated by using the finite element analysis (FEA method. The nephograms of magnetic flux density are agreement with theoretical analysis, which both confirm the correctness and effectiveness of the proposed approach.

Comparison of torque capability of three-phase permanent magnet synchronous motors with different permanent magnet arrangement

International Nuclear Information System (INIS)

Stumberger, Bojan; Stumberger, Gorazd; Hadziselimovic, Miralem; Hamler, Anton; Gorican, Viktor; Jesenik, Marko; Trlep, Mladen

2007-01-01

The paper presents a comparison of torque capability of three-phase permanent magnet synchronous motors with different permanent magnet arrangement. Motors with the following permanent magnet topologies were accounted for in the comparison: the surface-mounted permanent magnet synchronous motor (SMPMSM), the interior permanent magnet synchronous motor (IPMSM), the permanent magnet-assisted synchronous reluctance motor (PMASRM) and the flux reversal permanent magnet motor (FRPMM). Finite element method analysis is employed to determine the performance of each motor. Calculated performance of four-pole IPMSM determined by finite element method calculation is confirmed with the measurements at nearly constant nominal output power in the range of speed 3000-10,000 rpm

Lattice Boltzmann study of slip flow over structured surface with transverse slots

Science.gov (United States)

Chen, Wei; Wang, Kai; Wang, Lei; Hou, Guoxiang; Leng, Wenjun

2018-04-01

Slip flow over structured superhydrophobic surface with transverse slots is investigated by the lattice Boltzmann method. The Shan-Chen multiphase model is employed to simulate the flow over gas bubbles in the slots. The Carnahan-Starling equation of state is applied to obtain large density ratio. The interface thickness of the multiphase model is discussed. We find that the Cahn number Cn should be smaller than 0.02 when the temperature T = 0.5T c to restrict the influence of interface thickness on slip length. Influences of slot fraction on slip length is then studied, and the result is compared with single LB simulation of which the interface is treated as free-slip boundary. The slip length obtained by the multiphase model is a little smaller. After that, the shape of the liquid-gas interface is considered, and simulations with different initial protrusion angles and capillary numbers are performed. Effective slip length as a function of initial protrusion angle is obtained. The result is in qualitative agreement with a previous study and main features are reproduced. Furthermore, the influence of Capillary number Ca is studied. Larger Ca causes larger interface deformation and smaller slip length. But when the interface is concaving into the slot, this influence is less obvious.

Permanent-magnet switched-flux machine

Science.gov (United States)

Trzynadlowski, Andrzej M.; Qin, Ling

2010-01-12

A permanent-magnet switched-flux (PMSF) device has a ferromagnetic outer stator mounted to a shaft about a central axis extending axially through the PMSF device. Pluralities of top and bottom stator poles are respectively mounted in first and second circles, radially outwardly in first and second transverse planes extending from first and second sections of the central axis adjacent to an inner surface of the ferromagnetic outer stator. A ferromagnetic inner rotor is coupled to the shaft and has i) a rotor core having a core axis co-axial with the central axis; and ii) first and second discs having respective outer edges with first and second pluralities of permanent magnets (PMs) mounted in first and second circles, radially outwardly from the rotor core axis in the first and second transverse planes. The first and second pluralities of PMs each include PMs of alternating polarity.

Calculation of induced rotor current in induction motors using a slotted semi-analytical harmonic model

NARCIS (Netherlands)

Sprangers, R.L.J.; Gysen, B.L.J.; Paulides, J.J.H.; Waarma, J.; Lomonova, E.A.

2014-01-01

Recently, strong improvements have been made in the applicability of harmonic modeling techniques for electrical machines with slotted structures. Various implementations for permanent magnet motors and actuators have been investigated and applied in design and optimization tools. For the slotted

Evaluation of slot-to-slot coupling between dielectric slot waveguides and metal-insulator-metal slot waveguides.

Science.gov (United States)

Kong, Deqing; Tsubokawa, Makoto

2015-07-27

We numerically analyzed the power-coupling characteristics between a high-index-contrast dielectric slot waveguide and a metal-insulator-metal (MIM) plasmonic slot waveguide as functions of structural parameters. Couplings due mainly to the transfer of evanescent components in two waveguides generated high transmission efficiencies of 62% when the slot widths of the two waveguides were the same and 73% when the waveguides were optimized by slightly different widths. The maximum transmission efficiency in the slot-to-slot coupling was about 10% higher than that in the coupling between a normal slab waveguide and an MIM waveguide. Large alignment tolerance of the slot-to-slot coupling was also proved. Moreover, a small gap inserted into the interface between two waveguides effectively enhances the transmission efficiency, as in the case of couplings between a normal slab waveguide and an MIM waveguide. In addition, couplings with very wideband transmissions over a wavelength region of a few hundred nanometers were validated.

PECULIARITIES OF ASSIGNMENT OF ROLLING BEARING MOUNTING AND PARAMETERS OF GEOMETRIC ACCURACY OF MOUNTING SURFACES OF SHAFTS AND FRAMES

Directory of Open Access Journals (Sweden)

Adamenko Yu. І.

2017-04-01

Full Text Available The standards and methods concerning assignment of rolling bearing fit with shafts and frames via example of bearing 6-208 are analyzed. We set certain differences of recommendations according to GOST 3325-85, "Rolling bearings. Tolerance zones and technical requirements to mounting surfaces of shafts and frames. Attachment" and by reference of rolling bearing manufacturers. The following factors should be taken into consideration when assigning the mounting with the tension the internal ring of the bearing with shaft and mounting with a gap in the outer ring with a housing bore. The methods of achieving accuracy of mounting surfaces of shafts and frames via form tolerance assignment: roundness tolerance, profile of longitudinal cut, cross section, cylindricity and others. It is possible to limit the bearing rings in different ways, for example appointing the cylindrical mounting surfaces and bead end surfaces the appropriate tolerances, namely: coaxiality tolerance or full radial beat of mounting surfaces, and also perpendicularity tolerance, butt beats and full butt beats of mounting end surfaces. We suggest to expand methods of achieving the accuracy of shafts and frames depending on seriation of production and production operations metrology support.

Of Slot Machines and Broken Test Tubes

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 19; Issue 5. Of Slot Machines and Broken Test Tubes. S Mahadevan. General Article Volume 19 Issue 5 May 2014 pp 395-405. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/019/05/0395-0405. Keywords.

Shape-optimization of round-to-slot holes for improving film cooling effectiveness on a flat surface

Science.gov (United States)

Huang, Ying; Zhang, Jing-zhou; Wang, Chun-hua

2018-06-01

Single-objective optimization for improving adiabatic film cooling effectiveness is performed for single row of round-to-slot film cooling holes on a flat surface by using CFD analysis and surrogate approximation methods. Among the main geometric parameters, dimensionless hole-to-hole pitch ( P/ d) and slot length-to-diameter ( l/ d) are fixed as 2.4 and 2 respectively, and the other parameters (hole height-to-diameter ratio, slot width-to-diameter and inclination angle) are chosen as the design variables. Given a wide range of possible geometric variables, the geometric optimization of round-to-slot holes is carried out under two typical blowing ratios of M = 0.5 and M = 1.5 by selecting a spatially-averaged adiabatic film cooling effectiveness between x/ d = 2 and x/ d = 12 as the objective function to be maximized. Radial basis function neural network is applied for constructing the surrogate model and then the optimal design point is searched by a genetic algorithm. It is revealed that the optimal round-to-slot hole is of converging feature under a low blowing ratio but of diffusing feature under a high blowing ratio. Further, the influence principle of optimal round-to-slot geometry on film cooling performance is illustrated according to the detailed flow and thermal behaviors.

G-Tunnel pressurized slot-testing preparations

International Nuclear Information System (INIS)

Zimmerman, R.M.; Sifre-Soto, C.; Mann, K.L.; Bellman, R.A. Jr.; Luker, S.; Dodds, D.J.

1992-04-01

Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National laboratories elected to conduct a development program on pressurized slot testing and featured (1) development of an improved method to cut slots using a chain saw with diamond-tipped cutters, (2) measurements useful for determining in situ stresses normal to slots, (3) measurements applicable for determining the in situ modulus of deformation parallel to a drift surface, and (4) evaluations of the potentials of pressurized slot strength testing. This report describes the preparations leading to the measurements and evaluations

Permanent isolation surface barrier development plan

International Nuclear Information System (INIS)

Wing, N.R.

1994-01-01

The exhumation and treatment of wastes may not always be the preferred alternative in the remediation of a waste site. In-place disposal alternatives, under certain circumstances, may be the most desirable alternatives to use in the protection of human health and the environment. The implementation of an in-place disposal alternative will likely require some type of protective covering that will provide long-term isolation of the wastes from the accessible environment. Even if the wastes are exhumed and treated, a long-term barrier may still be needed to adequately dispose of the treated wastes or any remaining waste residuals. Currently, no open-quotes provenclose quotes long-term barrier is available. The Hanford Site Permanent Isolation Surface Barrier Development Program (BDP) was organized to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site. The permanent isolation barrier technology also could be used at other sites. Permanent isolation barriers use engineered layers of natural materials to create an integrated structure with redundant protective features. Drawings of conceptual permanent isolation surface barriers are shown. The natural construction materials (e.g., fine soil, sand, gravel, riprap, asphalt) have been selected to optimize barrier performance and longevity. The objective of current designs is to use natural materials to develop a maintenance-free permanent isolation surface barrier that isolates wastes for a minimum of 1,000 years by limiting water drainage to near-zero amounts; reducing the likelihood of plant, animal, and human intrusion; controlling the exhalation of noxious gases; and minimizing erosion-related problems

Permanent isolation surface barrier development plan

Energy Technology Data Exchange (ETDEWEB)

Wing, N.R.

1994-01-01

The exhumation and treatment of wastes may not always be the preferred alternative in the remediation of a waste site. In-place disposal alternatives, under certain circumstances, may be the most desirable alternatives to use in the protection of human health and the environment. The implementation of an in-place disposal alternative will likely require some type of protective covering that will provide long-term isolation of the wastes from the accessible environment. Even if the wastes are exhumed and treated, a long-term barrier may still be needed to adequately dispose of the treated wastes or any remaining waste residuals. Currently, no {open_quotes}proven{close_quotes} long-term barrier is available. The Hanford Site Permanent Isolation Surface Barrier Development Program (BDP) was organized to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site. The permanent isolation barrier technology also could be used at other sites. Permanent isolation barriers use engineered layers of natural materials to create an integrated structure with redundant protective features. Drawings of conceptual permanent isolation surface barriers are shown. The natural construction materials (e.g., fine soil, sand, gravel, riprap, asphalt) have been selected to optimize barrier performance and longevity. The objective of current designs is to use natural materials to develop a maintenance-free permanent isolation surface barrier that isolates wastes for a minimum of 1,000 years by limiting water drainage to near-zero amounts; reducing the likelihood of plant, animal, and human intrusion; controlling the exhalation of noxious gases; and minimizing erosion-related problems.

Slot-coupled CW standing wave accelerating cavity

Energy Technology Data Exchange (ETDEWEB)

Wang, Shaoheng; Rimmer, Robert; Wang, Haipeng

2017-05-16

A slot-coupled CW standing wave multi-cell accelerating cavity. To achieve high efficiency graded beta acceleration, each cell in the multi-cell cavity may include different cell lengths. Alternatively, to achieve high efficiency with acceleration for particles with beta equal to 1, each cell in the multi-cell cavity may include the same cell design. Coupling between the cells is achieved with a plurality of axially aligned kidney-shaped slots on the wall between cells. The slot-coupling method makes the design very compact. The shape of the cell, including the slots and the cone, are optimized to maximize the power efficiency and minimize the peak power density on the surface. The slots are non-resonant, thereby enabling shorter slots and less power loss.

Cusp-Gun Sixth-Harmonic Slotted Gyrotron

Science.gov (United States)

Stutzman, R. C.; McDermott, D. B.; Hirata Luhmann, Y., Jr.; Gallagher, D. A.; Spencer, T. A.

2000-10-01

A high-harmonic slotted gyrotron has been constructed at UC Davis to be driven by a 70 kV, 3.5 A, axis-encircling electron beam from a Northrop Grumman Cusp gun. The 94 GHz, slotted sixth-harmonic gyrotron is predicted to generate 50 kW with an efficiency of 20%. Using the profile of the adiabatic field reversal from the UC Davis superconducting test-magnet, EGUN simulations predict that an axis-encircling electron beam will be generated with an axial velocity spread of Δ v_z/v_z=10% for the desired velocity ratio of α =v_z/v_z=1.5. The design will also be presented for an 8th-harmonic W-band gyrotron whose magnetic field can be supplied by a lightweight permanent magnet.

Pole Shape Optimization of Permanent Magnet Synchronous Motors Using the Reduced Basis Technique

Directory of Open Access Journals (Sweden)

A. Jabbari

2010-03-01

Full Text Available In the present work, an integrated method of pole shape design optimization for reduction of torque pulsation components in permanent magnet synchronous motors is developed. A progressive design process is presented to find feasible optimal shapes. This method is applied on the pole shape optimization of two prototype permanent magnet synchronous motors, i.e., 4-poles/6-slots and 4-poles-12slots.

Permanent isolation surface barrier: Functional performance

International Nuclear Information System (INIS)

Wing, N.R.

1993-10-01

This document presents the functional performance parameters for permanent isolation surface barriers. Permanent isolation surface barriers have been proposed for use at the Hanford Site (and elsewhere) to isolate and dispose of certain types of waste in place. Much of the waste that would be disposed of using in-place isolation techniques is located in subsurface structures, such as solid waste burial grounds, tanks, vaults, and cribs. Unless protected in some way, the wastes could be transported to the accessible environment via transport pathways, such as water infiltration, biointrusion, wind and water erosion, human interference, and/or gaseous release

Design and analysis of tubular permanent magnet linear wave generator.

Science.gov (United States)

Si, Jikai; Feng, Haichao; Su, Peng; Zhang, Lufeng

2014-01-01

Due to the lack of mature design program for the tubular permanent magnet linear wave generator (TPMLWG) and poor sinusoidal characteristics of the air gap flux density for the traditional surface-mounted TPMLWG, a design method and a new secondary structure of TPMLWG are proposed. An equivalent mathematical model of TPMLWG is established to adopt the transformation relationship between the linear velocity of permanent magnet rotary generator and the operating speed of TPMLWG, to determine the structure parameters of the TPMLWG. The new secondary structure of the TPMLWG contains surface-mounted permanent magnets and the interior permanent magnets, which form a series-parallel hybrid magnetic circuit, and their reasonable structure parameters are designed to get the optimum pole-arc coefficient. The electromagnetic field and temperature field of TPMLWG are analyzed using finite element method. It can be included that the sinusoidal characteristics of air gap flux density of the new secondary structure TPMLWG are improved, the cogging force as well as mechanical vibration is reduced in the process of operation, and the stable temperature rise of generator meets the design requirements when adopting the new secondary structure of the TPMLWG.

Design and Analysis of Tubular Permanent Magnet Linear Wave Generator

Directory of Open Access Journals (Sweden)

Jikai Si

2014-01-01

Full Text Available Due to the lack of mature design program for the tubular permanent magnet linear wave generator (TPMLWG and poor sinusoidal characteristics of the air gap flux density for the traditional surface-mounted TPMLWG, a design method and a new secondary structure of TPMLWG are proposed. An equivalent mathematical model of TPMLWG is established to adopt the transformation relationship between the linear velocity of permanent magnet rotary generator and the operating speed of TPMLWG, to determine the structure parameters of the TPMLWG. The new secondary structure of the TPMLWG contains surface-mounted permanent magnets and the interior permanent magnets, which form a series-parallel hybrid magnetic circuit, and their reasonable structure parameters are designed to get the optimum pole-arc coefficient. The electromagnetic field and temperature field of TPMLWG are analyzed using finite element method. It can be included that the sinusoidal characteristics of air gap flux density of the new secondary structure TPMLWG are improved, the cogging force as well as mechanical vibration is reduced in the process of operation, and the stable temperature rise of generator meets the design requirements when adopting the new secondary structure of the TPMLWG.

Design and Analysis of Tubular Permanent Magnet Linear Wave Generator

Science.gov (United States)

Si, Jikai; Feng, Haichao; Su, Peng; Zhang, Lufeng

2014-01-01

Due to the lack of mature design program for the tubular permanent magnet linear wave generator (TPMLWG) and poor sinusoidal characteristics of the air gap flux density for the traditional surface-mounted TPMLWG, a design method and a new secondary structure of TPMLWG are proposed. An equivalent mathematical model of TPMLWG is established to adopt the transformation relationship between the linear velocity of permanent magnet rotary generator and the operating speed of TPMLWG, to determine the structure parameters of the TPMLWG. The new secondary structure of the TPMLWG contains surface-mounted permanent magnets and the interior permanent magnets, which form a series-parallel hybrid magnetic circuit, and their reasonable structure parameters are designed to get the optimum pole-arc coefficient. The electromagnetic field and temperature field of TPMLWG are analyzed using finite element method. It can be included that the sinusoidal characteristics of air gap flux density of the new secondary structure TPMLWG are improved, the cogging force as well as mechanical vibration is reduced in the process of operation, and the stable temperature rise of generator meets the design requirements when adopting the new secondary structure of the TPMLWG. PMID:25050388

Slot Antenna for Wireless Temperature Measurement Systems

DEFF Research Database (Denmark)

Acar, Öncel; Jakobsen, Kaj Bjarne

2016-01-01

This paper presents a novel clover-slot antenna for a surface-acoustic-wave sensor based wireless temperature measurement system. The slot is described by a parametric locus curve that has the shape of a clover. The antenna is operated at high temperatures, in rough environments, and has a 43......% fractional bandwidth at the 2.4 GHz ISM-band. The slot antenna has been optimized for excitation by a passive chip soldered onto it. Measurement results are compared with simulation results and show good agreements....

Congestion Pricing for Aircraft Pushback Slot Allocation

Science.gov (United States)

Zhang, Yaping

2017-01-01

In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the “external cost of surface congestion” is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm. PMID:28114429

Congestion Pricing for Aircraft Pushback Slot Allocation.

Science.gov (United States)

Liu, Lihua; Zhang, Yaping; Liu, Lan; Xing, Zhiwei

2017-01-01

In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the "external cost of surface congestion" is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm.

Congestion Pricing for Aircraft Pushback Slot Allocation.

Directory of Open Access Journals (Sweden)

Lihua Liu

Full Text Available In order to optimize aircraft pushback management during rush hour, aircraft pushback slot allocation based on congestion pricing is explored while considering monetary compensation based on the quality of the surface operations. First, the concept of the "external cost of surface congestion" is proposed, and a quantitative study on the external cost is performed. Then, an aircraft pushback slot allocation model for minimizing the total surface cost is established. An improved discrete differential evolution algorithm is also designed. Finally, a simulation is performed on Xinzheng International Airport using the proposed model. By comparing the pushback slot control strategy based on congestion pricing with other strategies, the advantages of the proposed model and algorithm are highlighted. In addition to reducing delays and optimizing the delay distribution, the model and algorithm are better suited for use for actual aircraft pushback management during rush hour. Further, it is also observed they do not result in significant increases in the surface cost. These results confirm the effectiveness and suitability of the proposed model and algorithm.

Bearing-Mounting Concept Accommodates Thermal Expansion

Science.gov (United States)

Nespodzany, Robert; Davis, Toren S.

1995-01-01

Pins or splines allow radial expansion without slippage. Design concept for mounting rotary bearing accommodates differential thermal expansion between bearing and any structure(s) to which bearing connected. Prevents buildup of thermal stresses by allowing thermal expansion to occur freely but accommodating expansion in such way not to introduce looseness. Pin-in-slot configuration also maintains concentricity.

A Novel Modular-Stator Outer-Rotor Flux-Switching Permanent-Magnet Motor

Directory of Open Access Journals (Sweden)

Jing Zhao

2017-07-01

Full Text Available A novel modular-stator outer-rotor flux-switching permanent-magnet (MSOR-FSPM motor is proposed and studied in this paper. Structure, operation and design principles of the MSOR-FSPM motor are introduced and analyzed. Considering that the combination of different pole number and slot number has a great influence on the motor performance, the optimum rotor pole number for the 12-stator-slot MSOR-FSPM motor is researched to obtain good performance and make full use of the space in the MSOR-FSPM motor. The influences of rotor pole number on cogging torque, torque ripple and electromagnetic torque are analyzed and a 12-slot/10-pole MSOR-FSPM motor was chosen for further study. Then, several main parameters of the 12-slot/10-pole MSOR-FSPM motor were optimized to reduce the torque ripple. Finally, the utilization of permanent magnet (PM in the MSOR-FSPM motor and a conventional outer-rotor flux-switching permanent-magnet (COR-FSPM motor are compared and analyzed from the point of view of magnetic flux path, and verified by the finite element method (FEM. The FEM results show that the PM volume of MSOR-FSPM motor is only 54.04% of that in a COR-FSPM motor, but its average electromagnetic torque can reach more than 75% of the torque of COR-FSPM motor.

Quadrature Slotted Surface Coil Pair for Magnetic Resonance Imaging at 4 Tesla: Phantom Study

Directory of Open Access Journals (Sweden)

Solis S.E.

2012-01-01

Full Text Available A coil array was composed of two slotted surface coils forming a structure with two plates at 900, each one having 6 circular slots and is introduced in this paper. Numerical simulations of the magnetic field of this coil array were performed at 170 MHz using the finite element method to study its behaviour. This coil array was developed for brain magnetic resonance imaging to be operated at the resonant frequency of 170 MHz in the transceiver mode and quadrature driven. Numerical simulations demonstrated that electromagnetic interaction between the coil elements is negligible, and that the magnetic field showed a good uniformity. Phantom images were acquired with our coil array and standard pulse sequences on a research-dedicated 4 Tesla scanner. In vitro images showed the feasibility of this coil array for standard pulses and high field magnetic resonance imaging.

Slotted Circularly Polarized Microstrip Antenna for RFID Application

Directory of Open Access Journals (Sweden)

S. Kumar

2017-12-01

Full Text Available A single layer coaxial fed rectangular microstrip slotted antenna for circular polarization (CP is proposed for radio frequency identification (RFID application. Two triangular shaped slots and one rectangular slot along the diagonal axis of a square patch have been embedded. Due to slotted structure along the diagonal axis and less surface area, good quality of circular polarization has been obtained with the reduction in the size of microstrip antenna by 4.04 %. Circular polarization radiation performance has been studied by size and angle variation of diagonally slotted structures. The experimental result found for 10-dB return loss is 44 MHz with 10MHz of 3dB Axial Ratio (AR bandwidth respectively at the resonant frequency 910 MHz. The overall proposed antenna size including the ground plane is 80 mm x 80 mm x 4.572 mm.

Initial rotor position estimation and sliding preventing for elevators with surface-mounted PMSMs

Science.gov (United States)

Liu, Feng; Shen, Anwen; Tang, Qipeng; Xu, Jinbang

2016-03-01

Improved methods of initial rotor position estimation and sliding prevention are presented in this paper for elevators with surface-mounted permanent magnet synchronous machines (SPMSMs). In contrast to most of the existing literature, in this paper, estimation errors caused by stator resistance and dead time are analysed in detail. The improved estimation method can reduce the errors greatly without dead-time compensations and knowledge of motor parameters. Besides, an observer-based feedforward compensation of load torque is introduced to elevator applications to prevent sliding during the starting process. Since the torque observer is widely used in other motor applications, we focus on the impact caused by the change in inertia. Finally, a series of experiments are performed on a testing system with two 13.4 kW SPMSMs and drivers to illustrate the effectiveness and improvement of the method.

Mounting clips for panel installation

Science.gov (United States)

Cavieres, Andres; Al-Haddad, Tristan; Goodman, Joseph; Valdes, Francisco

2017-02-14

An exemplary mounting clip for removably attaching panels to a supporting structure comprises a base, spring locking clips, a lateral flange, a lever flange, and a spring bonding pad. The spring locking clips extend upwardly from the base. The lateral flange extends upwardly from a first side of the base. The lateral flange comprises a slot having an opening configured to receive at least a portion of one of the one or more panels. The lever flange extends outwardly from the lateral flange. The spring bonding flange extends downwardly from the lever flange. At least a portion of the first spring bonding flange comprises a serrated edge for gouging at least a portion of the one or more panels when the one or more panels are attached to the mounting clip to electrically and mechanically couple the one or more panels to the mounting clip.

Safety effects of permanent running lights for bicycles

DEFF Research Database (Denmark)

Madsen, Jens Chr. Overgaard; Andersen, T.; Lahrmann, Harry

2013-01-01

, including all recorded bicycle accidents with personal injury to the participating cyclist, is 19% lower for cyclists with permanent running lights mounted; indicating that the permanent bicycle running light significantly improves traffic safety for cyclists. The study shows that use of permanent bicycle......Making the use of daytime running lights mandatory for motor vehicles is generally documented to have had a positive impact upon traffic safety. Improving traffic safety for bicyclists is a focal point in the road traffic safety work in Denmark. In 2004 and 2005 a controlled experiment including...... 3845 cyclists was carried out in Odense, Denmark in order to examine, if permanent running lights mounted to bicycles would improve traffic safety for cyclists. The permanent running lights were mounted to 1845 bicycles and the accident rate was recorded through 12 months for this treatment group...

Comparison of PMAC Machines for Starter-Generator Application in a Series Hybrid-Electric Bus

OpenAIRE

Sinisa Jurkovic; Elias G. Strangas

2011-01-01

This paper presents a comparative study of outer rotor PMAC machine candidates for starter-generator application in hybrid bus with series power train configuration. PMAC machines with interior and surface mount permanent magnets are considered and compared, although a complete analysis is only carried out for the SPM. Different design aspects such as concentrated versus distributed windings as well as interior and exterior rotor structures are evaluated. Different slot numbers per pole per p...

Design, analysis and fabrication of a linear permanent magnet ...

Indian Academy of Sciences (India)

MONOJIT SEAL

Linear permanent magnet synchronous machine; LPMSM—fabrication; design optimisation; finite-element ... induction motor (LIM) prototype was patented in 1890 [1]. Since then, linear ..... Also, for manual winding, more slot area is allotted to ...

G-tunnel pressurized slot-testing evaluations

International Nuclear Information System (INIS)

Zimmerman, R.M.; Sifre-Soto, C.; Mann, K.L.; Bellman, R.A. Jr.; Luker, S.; Dodds, D.J.

1992-04-01

Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National Laboratories elected to conduct a development program to enhance mechanical-type measurements. The program was focused on pressurized slot testing and featured (1) development of an improved method to cut slots using a chain saw with diamond-tipped cutters, (2) measurements useful for determining in situ stresses normal to slots, (3) measurements applicable for determining the in situ modulus of deformation parallel to a drift surface, and (4) evaluations of pressurized slot strength testing results and methods. This report contains data interpretation and evaluations. Included are recommendations for future efforts. This third report contains the interpretations of the testing with emphasis on the measurement results as they apply to describing rock behavior. In particular, emphases are placed on (1) normal stress determinations using the flatjack cancellation (FC) method, (2) modulus of deformation determinations, and (3) high pressure investigations. Most of the material in the first two reports is not repeated here. Appropriate data are repeated in tabular form

Permanent magnet working point ripple in synchronous generators

Directory of Open Access Journals (Sweden)

Stefan Sjökvist

2017-04-01

Full Text Available Permanent magnets (PMs are today widely used in electrical machines of all sorts. With their increase in popularity, the amount of research has increased as well. In this study, the magnetic flux density ripple of the working point of the PMs in a 100 kW PM synchronous generator has been investigated for three different load cases: no load, AC load, and DC load. The PMs will be subjected to a shift in working point as a consequence of the characteristics of the electrical loading. This study is based on finite element method simulations where the ripple of the magnetic flux density in the PMs was recorded at three positions within a PM. The slot harmonic of 7.5 times the electrical frequency (f(el was present in the results for all load cases, but mainly at the surface of the PM, as expected. Results showed an unexpected harmonic of 1.5 f(el, assumed to be an undertone of the slot harmonics. The 6f(el harmonic for the DC load case was significantly higher than for the AC load case and is caused by the current fluctuation during passive rectification. For the studied machine, the added harmonics in the magnetic field due to passive rectification are less than the slot-related harmonics.

Transport Infrastructure Slot Allocation

NARCIS (Netherlands)

Koolstra, K.

2005-01-01

In this thesis, transport infrastructure slot allocation has been studied, focusing on selection slot allocation, i.e. on longer-term slot allocation decisions determining the traffic patterns served by infrastructure bottlenecks, rather than timetable-related slot allocation problems. The

A hybrid analytical model for open-circuit field calculation of multilayer interior permanent magnet machines

Science.gov (United States)

Zhang, Zhen; Xia, Changliang; Yan, Yan; Geng, Qiang; Shi, Tingna

2017-08-01

Due to the complicated rotor structure and nonlinear saturation of rotor bridges, it is difficult to build a fast and accurate analytical field calculation model for multilayer interior permanent magnet (IPM) machines. In this paper, a hybrid analytical model suitable for the open-circuit field calculation of multilayer IPM machines is proposed by coupling the magnetic equivalent circuit (MEC) method and the subdomain technique. In the proposed analytical model, the rotor magnetic field is calculated by the MEC method based on the Kirchhoff's law, while the field in the stator slot, slot opening and air-gap is calculated by subdomain technique based on the Maxwell's equation. To solve the whole field distribution of the multilayer IPM machines, the coupled boundary conditions on the rotor surface are deduced for the coupling of the rotor MEC and the analytical field distribution of the stator slot, slot opening and air-gap. The hybrid analytical model can be used to calculate the open-circuit air-gap field distribution, back electromotive force (EMF) and cogging torque of multilayer IPM machines. Compared with finite element analysis (FEA), it has the advantages of faster modeling, less computation source occupying and shorter time consuming, and meanwhile achieves the approximate accuracy. The analytical model is helpful and applicable for the open-circuit field calculation of multilayer IPM machines with any size and pole/slot number combination.

Frequency Reconfigurable Circular Patch Antenna with an Arc-Shaped Slot Ground Controlled by PIN Diodes

Directory of Open Access Journals (Sweden)

Yao Chen

2017-01-01

Full Text Available In this paper, a compact frequency reconfigurable circular patch antenna with an arc-shaped slot loaded in the ground layer is proposed for multiband wireless communication applications. By controlling the ON/OFF states of the five PIN diodes mounted on the arc-shaped slot, the effective length of the arc-shaped slot and the effective length of antennas current are changed, and accordingly six-frequency band reconfiguration can be achieved. The simulated and measured results show that the antenna can operate from 1.82 GHz to 2.46 GHz, which is located in DCS1800 (1.71–1.88 GHz, UMTS (2.11–2.20 GHz, WiBro (2.3–2.4 GHz, and Bluetooth (2.4–2.48 GHz frequency bands and so forth. Compared to the common rectangular slot circular patch antenna, the proposed arc-shaped slot circular patch antenna not only has a better rotational symmetry with the circular patch and substrate but also has more compact size. For the given operating frequency at 1.82 GHz, over 55% area reduction is achieved in this design with respect to the common design with rectangular slot. Since the promising frequency reconfiguration, this antenna may have potential applications in modern multiband and multifunctional mobile communication systems.

A Surface-Mounted Rotor State Sensing System, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — A surface-mounted instrumentation system for measuring rotor blade motions on rotorcraft, for use both in flight and in wind tunnel testing, is proposed for...

Application of permanent magnet BaFe12O19 and NdFeB on small scale low speed permanent magnet generator

International Nuclear Information System (INIS)

Pudji Irasari; Novrita Idayanti

2009-01-01

Designing and manufacturing of low speed permanent magnet generator (PMG) for small scale electric power plant have been conducted. In this paper, the characteristics of generator using permanent magnet of barium ferrite (BaFe 12 O 19 ) and neodymium iron boron (NdFeB) were compared. Surface mounted type is selected as the rotor structure as all flux faces to stator winding and take a role in energy conversion. The experiment result demonstrates that at nominal speed, generator with BaFe 12 O 19 magnet can only generate power of 8.87 W while generator with NdFeB magnet can generate power of 1,988.93 W. (author)

A Model for Analyzing a Five-Phase Fractional-Slot Permanent Magnet Tubular Linear Motor with Modified Winding Function Approach

Directory of Open Access Journals (Sweden)

Bo Zhang

2016-01-01

Full Text Available This paper presents a model for analyzing a five-phase fractional-slot permanent magnet tubular linear motor (FSPMTLM with the modified winding function approach (MWFA. MWFA is a fast modeling method and it gives deep insight into the calculations of the following parameters: air-gap magnetic field, inductances, flux linkages, and detent force, which are essential in modeling the motor. First, using a magnetic circuit model, the air-gap magnetic density is computed from stator magnetomotive force (MMF, flux barrier, and mover geometry. Second, the inductances, flux linkages, and detent force are analytically calculated using modified winding function and the air-gap magnetic density. Finally, a model has been established with the five-phase Park transformation and simulated. The calculations of detent force reveal that the end-effect force is the main component of the detent force. This is also proven by finite element analysis on the motor. The accuracy of the model is validated by comparing with the results obtained using semianalytical method (SAM and measurements to analyze the motor’s transient characteristics. In addition, the proposed method requires less computation time.

A Novel Modular-Stator Outer-Rotor Flux-Switching Permanent-Magnet Motor

OpenAIRE

Jing Zhao; Yun Zheng; Congcong Zhu; Xiangdong Liu; Bin Li

2017-01-01

A novel modular-stator outer-rotor flux-switching permanent-magnet (MSOR-FSPM) motor is proposed and studied in this paper. Structure, operation and design principles of the MSOR-FSPM motor are introduced and analyzed. Considering that the combination of different pole number and slot number has a great influence on the motor performance, the optimum rotor pole number for the 12-stator-slot MSOR-FSPM motor is researched to obtain good performance and make full use of the space in the MSOR-FSP...

A hybrid analytical model for open-circuit field calculation of multilayer interior permanent magnet machines

Energy Technology Data Exchange (ETDEWEB)

Zhang, Zhen [School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072 (China); Xia, Changliang [School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072 (China); Tianjin Engineering Center of Electric Machine System Design and Control, Tianjin 300387 (China); Yan, Yan, E-mail: yanyan@tju.edu.cn [School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072 (China); Geng, Qiang [Tianjin Engineering Center of Electric Machine System Design and Control, Tianjin 300387 (China); Shi, Tingna [School of Electrical Engineering and Automation, Tianjin University, Tianjin 300072 (China)

2017-08-01

Highlights: • A hybrid analytical model is developed for field calculation of multilayer IPM machines. • The rotor magnetic field is calculated by the magnetic equivalent circuit method. • The field in the stator and air-gap is calculated by subdomain technique. • The magnetic scalar potential on rotor surface is modeled as trapezoidal distribution. - Abstract: Due to the complicated rotor structure and nonlinear saturation of rotor bridges, it is difficult to build a fast and accurate analytical field calculation model for multilayer interior permanent magnet (IPM) machines. In this paper, a hybrid analytical model suitable for the open-circuit field calculation of multilayer IPM machines is proposed by coupling the magnetic equivalent circuit (MEC) method and the subdomain technique. In the proposed analytical model, the rotor magnetic field is calculated by the MEC method based on the Kirchhoff’s law, while the field in the stator slot, slot opening and air-gap is calculated by subdomain technique based on the Maxwell’s equation. To solve the whole field distribution of the multilayer IPM machines, the coupled boundary conditions on the rotor surface are deduced for the coupling of the rotor MEC and the analytical field distribution of the stator slot, slot opening and air-gap. The hybrid analytical model can be used to calculate the open-circuit air-gap field distribution, back electromotive force (EMF) and cogging torque of multilayer IPM machines. Compared with finite element analysis (FEA), it has the advantages of faster modeling, less computation source occupying and shorter time consuming, and meanwhile achieves the approximate accuracy. The analytical model is helpful and applicable for the open-circuit field calculation of multilayer IPM machines with any size and pole/slot number combination.

effect of number of rotor poles on ac losses of permanent magnet

African Journals Online (AJOL)

HOD

A study on permanent magnet (PM) eddy current and core losses of dual-stator PM machines is investigated in this paper. ... material in the retaining sleeves of surface-mounted ... rotor-pole numbers (13-poleand 14-pole in particular) ... Table 2: Optimized Machine Parameters. Number of rotor poles. 4. 5. 7. 8. 10. 11. 13. 14.

Optimal Design of Stator Interior Permanent Magnet Machine with Minimized Cogging Torque for Wind Power Application

DEFF Research Database (Denmark)

Chen, Zhe; Zhang, Jianzhong; Cheng, Ming

2008-01-01

This paper proposes a new approach to minimize the cogging torque of a stator interior permanent magnet (SIPM) machine. The optimization of stator slot gap and permanent magnet is carried out and the cogging torque ripple is analyzed by using finite element analysis. Experiments on a prototype...

Reduction of Cogging Torque in Dual Rotor Permanent Magnet Generator for Direct Coupled Wind Energy Systems

Science.gov (United States)

Paulsamy, Sivachandran

2014-01-01

In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging torque in dual rotor radial flux permanent magnet generator (DRFPMG) for direct coupled stand alone wind energy systems (SAWES). Three methods were applied to reduce the cogging torque in DRFPMG. The methods were changing slot opening width, changing magnet pole arc width and shifting of slot openings. A combination of these three methods was applied to reduce the cogging torque to a level suitable for direct coupled SAWES. Both determination and reduction of cogging torque were carried out by finite element analysis (FEA) using MagNet Software. The cogging torque of DRFPMG has been reduced without major change in induced emf. A prototype of 1 kW, 120 rpm DRFPMG was fabricated and tested to validate the simulation results. The test results have good agreement with the simulation predictions. PMID:25202746

Reduction of cogging torque in dual rotor permanent magnet generator for direct coupled wind energy systems.

Science.gov (United States)

Paulsamy, Sivachandran

2014-01-01

In wind energy systems employing permanent magnet generator, there is an imperative need to reduce the cogging torque for smooth and reliable cut in operation. In a permanent magnet generator, cogging torque is produced due to interaction of the rotor magnets with slots and teeth of the stator. This paper is a result of an ongoing research work that deals with various methods to reduce cogging torque in dual rotor radial flux permanent magnet generator (DRFPMG) for direct coupled stand alone wind energy systems (SAWES). Three methods were applied to reduce the cogging torque in DRFPMG. The methods were changing slot opening width, changing magnet pole arc width and shifting of slot openings. A combination of these three methods was applied to reduce the cogging torque to a level suitable for direct coupled SAWES. Both determination and reduction of cogging torque were carried out by finite element analysis (FEA) using MagNet Software. The cogging torque of DRFPMG has been reduced without major change in induced emf. A prototype of 1 kW, 120 rpm DRFPMG was fabricated and tested to validate the simulation results. The test results have good agreement with the simulation predictions.

EFFECTS OF SLOTTED BLADING ON SECONDARY FLOW IN HIGHLY LOADED COMPRESSOR CASCADE

Directory of Open Access Journals (Sweden)

RAMZI MDOUKI

2013-10-01

Full Text Available With the aim to increase allowable blade loadings and enlarge stable operating range in highly loaded compressor, this work is carried out in order to explore the potential of passive control via slotted bladings in linear cascade configurations under both design and stall conditions. Through an extensive 2D-numerical study, the effects of location, width and slope of slots were analysed and the best configuration was identified. Based on the optimal slot, the 3D aerodynamic performances of cascade were studied and the influence of slotted blading to control endwall flow was investigated. Both 2D and 3D calculations are performed on steady RANS solver with standard k-epsilon turbulence model and low Mach number regime. The total loss coefficient, turning angle and flow visualizations on the blade and end-wall surfaces are adopted to describe the different configurations. The obtained results show, for 2D situation, that a maximum of 28.3% reduction in loss coefficient had been reached and the flow turning was increased with approximately 5°. Concerning 3D flow fields the slots marked their benefit at large incoming flow angles which delays the separation on both end wall and blade suction surface at mid span. However, at design conditions, the slotted blades are not able to control secondary flows near the wall and so, lose their potential.

Comparative analysis of various methods for modelling permanent magnet machines

NARCIS (Netherlands)

Ramakrishnan, K.; Curti, M.; Zarko, D.; Mastinu, G.; Paulides, J.J.H.; Lomonova, E.A.

2017-01-01

In this paper, six different modelling methods for permanent magnet (PM) electric machines are compared in terms of their computational complexity and accuracy. The methods are based primarily on conformal mapping, mode matching, and harmonic modelling. In the case of conformal mapping, slotted air

Asynchronous slip-ring motor synchronized with permanent magnets

Directory of Open Access Journals (Sweden)

Glinka Tadeusz

2017-03-01

Full Text Available The electric LSPMSM motor presented in the paper differs from standard induction motor by rotor design. The insulated start-up winding is located in slots along the rotor circumference. The winding ends are connected to the slip-rings. The rotor core contains permanent magnets. The electromechanical characteristics for synchronous operation were calculated, as were the start-up characteristics for operation with a short-circuited rotor winding. Two model motors were used for the calculations, the V-shaped Permanent Magnet (VPM – Fig. 3, and the Linear Permanent Magnet (IPM – Fig. 4, both rated at 14.5 kW. The advantages of the investigated motor are demonstrated in the conclusions.

Dovetail spoke internal permanent magnet machine

Science.gov (United States)

Alexander, James Pellegrino [Ballston Lake, NY; EL-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Lokhandwalla, Murtuza [Clifton Park, NY; Shah, Manoj Ramprasad [Latham, NY; VanDam, Jeremy Daniel [West Coxsackie, NY

2011-08-23

An internal permanent magnet (IPM) machine is provided. The IPM machine includes a stator assembly and a stator core. The stator core also includes multiple stator teeth. The stator assembly is further configured with stator windings to generate a stator magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity. The IPM machine also includes a rotor assembly and a rotor core. The rotor core is disposed inside the cavity and configured to rotate about the longitudinal axis. The rotor assembly further includes a shaft. The shaft further includes multiple protrusions alternately arranged relative to multiple bottom structures provided on the shaft. The rotor assembly also includes multiple stacks of laminations disposed on the protrusions and dovetailed circumferentially around the shaft. The rotor assembly further includes multiple pair of permanent magnets for generating a magnetic field, which magnetic field interacts with the stator magnetic field to produce a torque. The multiple pair of permanent magnets are disposed between the stacks. The rotor assembly also includes multiple middle wedges mounted between each pair of the multiple permanent magnets.

Analysis and Design Optimization of a Coaxial Surface-Mounted Permanent-Magnet Magnetic Gear

DEFF Research Database (Denmark)

Zhang, Xiaoxu; Liu, Xiao; Wang, Chao

2014-01-01

). The analytical field solution allows the prediction of the magnetic torque, which is formulated as a function of design parameters. The impacts of key design parameters on the torque capability are then studied and some significant observations are summarized. Furthermore, the particle swarm optimization (PSO...... on one or another. The results shows that the highest torque density of 157 kNm/m3 is achieved with the consideration focusing on the torque capability only, then the highest torque per permanent magnet (PM) consumption could be improved to 145 Nm/kg by taking the material cost into account....... By synthesizing the torque capability and material cost, a 124 kNm/m3 of torque density and a 128 Nm/kg of torque per PM consumption could be achieved simultaneously by the optimal design....

Effects of geometry on slot-jet film cooling performance

Energy Technology Data Exchange (ETDEWEB)

Hyams, D.G.; McGovern, K.T.; Leylek, J.H. [Clemson Univ., SC (United States)

1995-10-01

The physics of the film cooling process for shaped, inclined slot-jets with realistic slot-length-to-width ratios (L/s) is studied for a range of blowing ratio (M) and density ratio (DR) parameters typical of gas turbine operations. For the first time in the open literature, the effect of inlet and exit shaping of the slot-jet on both flow and thermal field characteristics is isolated, and the dominant mechanisms responsible for differences in these characteristics are documented. A previously documented computational methodology was applied for the study of four distinct configurations: (1) slot with straight edges and sharp corners (reference case); (2) slot with shaped inlet region; (3) slot with shaped exit region; and (4) slot with both shaped inlet and exit regions. Detailed field results as well as surface phenomena involving adiabatic film effectiveness ({eta}) and heat transfer coefficient (h) are presented. It is demonstrated that both {eta} and h results are vital in the proper assessment of film cooling performance. All simulations were carried out using a multi-block, unstructured/adaptive grid, fully explicit, time-marching solver with multi-grid, local time stepping, and residual smoothing type acceleration techniques. Special attention was paid to and full documentation provided for: (1) proper modeling of the physical phenomena; (2) exact geometry and high quality grid generation techniques; (3) discretization schemes; and (4) turbulence modeling issues. The key parameters M and DR were varied from 1.0 to 2.0 and 1.5 to 2.0, respectively, to show their influence. Simulations were repeated for slot length-to-width ratio (L/s) of 3.0 and 4.5 in order to explain the effects of this important parameter. Additionally, the performance of two popular turbulence models, standard k-F, and RNG k-E, were studied to establish their ability to handle highly elliptic jet/crossflow interaction type processes.

Photovoltaic mounting/demounting unit

DEFF Research Database (Denmark)

2014-01-01

The present invention relates to a photovoltaic arrangement comprising a photovoltaic assembly comprising a support structure defining a mounting surface onto which a photovoltaic module is detachably mounted; and a mounting/demounting unit comprising at least one mounting/demounting apparatus...... which when the mounting/demounting unit is moved along the mounting surface, causes the photovoltaic module to be mounted or demounted to the support structure; wherein the photovoltaic module comprises a carrier foil and wherein a total thickness of the photo voltaic module is below 500 muiotaeta....... The present invention further relates to an associated method for mounting/demounting photovoltaic modules....

Measurement of the depth of narrow slotted sections in eddy current reference standards

Science.gov (United States)

Kim, Young-Joo; Kim, Young-gil; Ahn, Bongyoung; Yoon, Dong-Jin

2007-02-01

The dimensions of the slots in eddy current (EC) reference standards are too narrow to be measured by general depth measurement methods such as the optical (laser) or stylus methods. However, measurement of the dimensions of the machined slots is a prerequisite to using the blocks as references. The present paper suggests a measurement method for the slotted section using an ultrasonic test. The width and depth of the slots measured in our study are roughly 0.1 mm and 0.5 mm, respectively. The time of flight (TOF) of the ultrasonic wave was measured precisely. The ultrasonic velocity in the material of the EC reference standard was calculated with the measured values of the TOF and its thickness. Reflected waves from the tip of the slot and the bottom surface of the EC standard were successfully classified. Using this method we have successfully determined the depth of the slotted section.

Improvement of permanent magnet machines performance by including magnetic shells into the rotor geometry

International Nuclear Information System (INIS)

Alnaemi, F.; Moses, A.J.

2003-01-01

FEM modelling of PM motor was carried out to demonstrate the effects of the addition of various types of ferromagnetic tubes (shell) to a rotor of surface mount permanent magnet motor. An enhancement in magnet operating point towards the high field region is obtained. A shell made of amorphous ribbon offers optimum advantages

Novel ocean energy permanent magnet linear generator buoy

Energy Technology Data Exchange (ETDEWEB)

Rhinefrank, K.; Agamloh, E.B.; Jouanne, A. von; Wallace, A.K.; Prudell, J.; Kimble, K.; Aills, J.; Schmidt, E.; Schacher, A. [School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331-3211 (United States); Chan, P.; Sweeny, B. [Department of Mechanical Engineering, Oregon State University, Corvallis, OR 97331-3211 (United States)

2006-07-15

This paper describes the research, design, construction and prototype testing process of a novel ocean energy direct drive permanent magnet linear generator buoy. The buoy employs the vertical component of the motion of ocean waves to power a linear generator. The generator consists of a permanent magnet field system (mounted on the central translator shaft) and an armature, in which the power is generated (mounted on the buoy). The translator shaft is anchored to the sea floor, and the buoy/floater moves armature coils relative to the permanent magnet translator to induce voltages. The electrical and mechanical structures of the buoy generator are provided, along with performance characteristics, including voltage, current and developed power. (author)

High S/N Ratio Slotted Step Piezoresistive Microcantilever Designs for Biosensors

Directory of Open Access Journals (Sweden)

Mohd Zahid Ansari

2013-03-01

Full Text Available This study proposes new microcantilever designs in slotted step configuration to improve the S/N ratio of surface stress-based sensors used in physical, chemical, biochemical and biosensor applications. The cantilevers are made of silicon dioxide with a u-shaped silicon piezoresistor in p-doped. The cantilever step length and piezoresistor length is varied along with the operating voltage to characterise the surface stress sensitivity and thermal drifting sensitivity of the cantilevers when used as immunosensor. The numerical analysis is performed using ANSYS Multiphysics. Results show the surface stress sensitivity and the S/N ratio of the slotted step cantilevers is improved by more than 32% and 22%, respectively, over its monolithic counterparts.

High S/N ratio slotted step piezoresistive microcantilever designs for biosensors.

Science.gov (United States)

Ansari, Mohd Zahid; Cho, Chongdu

2013-03-26

This study proposes new microcantilever designs in slotted step configuration to improve the S/N ratio of surface stress-based sensors used in physical, chemical, biochemical and biosensor applications. The cantilevers are made of silicon dioxide with a u-shaped silicon piezoresistor in p-doped. The cantilever step length and piezoresistor length is varied along with the operating voltage to characterise the surface stress sensitivity and thermal drifting sensitivity of the cantilevers when used as immunosensor. The numerical analysis is performed using ANSYS Multiphysics. Results show the surface stress sensitivity and the S/N ratio of the slotted step cantilevers is improved by more than 32% and 22%, respectively, over its monolithic counterparts.

Design optimization for permanent magnet machine with efficient slot per pole ratio

Science.gov (United States)

Potnuru, Upendra Kumar; Rao, P. Mallikarjuna

2018-04-01

This paper presents a methodology for the enhancement of a Brush Less Direct Current motor (BLDC) with 6Poles and 8slots. In particular; it is focused on amulti-objective optimization using a Genetic Algorithmand Grey Wolf Optimization developed in MATLAB. The optimization aims to maximize the maximum output power value and minimize the total losses of a motor. This paper presents an application of the MATLAB optimization algorithms to brushless DC (BLDC) motor design, with 7 design parameters chosen to be free. The optimal design parameters of the motor derived by GA are compared with those obtained by Grey Wolf Optimization technique. A comparative report on the specified enhancement approaches appearsthat Grey Wolf Optimization technique has a better convergence.

Small angle slot divertor concept for long pulse advanced tokamaks

Science.gov (United States)

Guo, H. Y.; Sang, C. F.; Stangeby, P. C.; Lao, L. L.; Taylor, T. S.; Thomas, D. M.

2017-04-01

SOLPS-EIRENE edge code analysis shows that a gas-tight slot divertor geometry with a small-angle (glancing-incidence) target, named the small angle slot (SAS) divertor, can achieve cold, dissipative/detached divertor conditions at relatively low values of plasma density at the outside midplane separatrix. SAS exhibits the following key features: (1) strong enhancement of the buildup of neutral density in a localized region near the plasma strike point on the divertor target; (2) spreading of the cooling front across the divertor target with the slot gradually flaring out from the strike point, thus effectively reducing both heat flux and erosion on the entire divertor target surface. Such a divertor may potentially provide a power and particle handling solution for long pulse advanced tokamaks.

Preparation of samples for leaf architecture studies, a method for mounting cleared leaves.

Science.gov (United States)

Vasco, Alejandra; Thadeo, Marcela; Conover, Margaret; Daly, Douglas C

2014-09-01

Several recent waves of interest in leaf architecture have shown an expanding range of approaches and applications across a number of disciplines. Despite this increased interest, examination of existing archives of cleared and mounted leaves shows that current methods for mounting, in particular, yield unsatisfactory results and deterioration of samples over relatively short periods. Although techniques for clearing and staining leaves are numerous, published techniques for mounting leaves are scarce. • Here we present a complete protocol and recommendations for clearing, staining, and imaging leaves, and, most importantly, a method to permanently mount cleared leaves. • The mounting protocol is faster than other methods, inexpensive, and straightforward; moreover, it yields clear and permanent samples that can easily be imaged, scanned, and stored. Specimens mounted with this method preserve well, with leaves that were mounted more than 35 years ago showing no signs of bubbling or discoloration.

Sensorless Control of Permanent Magnet Synchronous Machines

DEFF Research Database (Denmark)

Matzen, Torben N.

Permanent magnet machines, with either surface mounted or embedded magnets on the rotor, are becoming more common due to the key advantages of higher energy conversion efficiency and higher torque density compared to the classical induction machine. Besides energy efficiency the permanent magnet...... the synchronous machine requires knowledge of the rotor shaft position due to the synchronous and undamped nature of the machine. The rotor position may be measured using a mechanical sensor, but the sensor reduces reliability and adds cost to the system and for this reason sensorless control methods started...... are dependent on the phase currents and rotor position. Based on the flux linkages the differential inductances are determined and used to establish the inductance saliency in terms of ratio and orientation. The orientation and its dependence on the current and rotor position are used to analyse the behaviour...

Low-loss slot waveguides with silicon (111 surfaces realized using anisotropic wet etching

Directory of Open Access Journals (Sweden)

Kapil Debnath

2016-11-01

Full Text Available We demonstrate low-loss slot waveguides on silicon-on-insulator (SOI platform. Waveguides oriented along the (11-2 direction on the Si (110 plane were first fabricated by a standard e-beam lithography and dry etching process. A TMAH based anisotropic wet etching technique was then used to remove any residual side wall roughness. Using this fabrication technique propagation loss as low as 3.7dB/cm was realized in silicon slot waveguide for wavelengths near 1550nm. We also realized low propagation loss of 1dB/cm for silicon strip waveguides.

Preparation of Samples for Leaf Architecture Studies, A Method for Mounting Cleared Leaves

Directory of Open Access Journals (Sweden)

Alejandra Vasco

2014-09-01

Full Text Available Premise of the study: Several recent waves of interest in leaf architecture have shown an expanding range of approaches and applications across a number of disciplines. Despite this increased interest, examination of existing archives of cleared and mounted leaves shows that current methods for mounting, in particular, yield unsatisfactory results and deterioration of samples over relatively short periods. Although techniques for clearing and staining leaves are numerous, published techniques for mounting leaves are scarce. Methods and Results: Here we present a complete protocol and recommendations for clearing, staining, and imaging leaves, and, most importantly, a method to permanently mount cleared leaves. Conclusions: The mounting protocol is faster than other methods, inexpensive, and straightforward; moreover, it yields clear and permanent samples that can easily be imaged, scanned, and stored. Specimens mounted with this method preserve well, with leaves that were mounted more than 35 years ago showing no signs of bubbling or discoloration.

Photovoltaic module mounting system

Science.gov (United States)

Miros, Robert H. J. [Fairfax, CA; Mittan, Margaret Birmingham [Oakland, CA; Seery, Martin N [San Rafael, CA; Holland, Rodney H [Novato, CA

2012-04-17

A solar array mounting system having unique installation, load distribution, and grounding features, and which is adaptable for mounting solar panels having no external frame. The solar array mounting system includes flexible, pedestal-style feet and structural links connected in a grid formation on the mounting surface. The photovoltaic modules are secured in place via the use of attachment clamps that grip the edge of the typically glass substrate. The panel mounting clamps are then held in place by tilt brackets and/or mid-link brackets that provide fixation for the clamps and align the solar panels at a tilt to the horizontal mounting surface. The tilt brackets are held in place atop the flexible feet and connected link members thus creating a complete mounting structure.

Design and Comparison of a Novel Stator Interior Permanent Magnet Generator for Direct-Drive Wind Turbines

DEFF Research Database (Denmark)

Zhang, Johan Xi; Chen, Zhe; Cheng, M.

2007-01-01

A novel stator interior permanent magnet generator (SIPMG) is presented. A modular stator design is used for convenience in manufacture and maintenance. The generator has the advantages of rugged rotor and concentrated winding design whereas the torque ripple is smaller than that produced...... by a doubly salient machine. Several low-speed multi-pole SIPMGs are designed for direct-drive wind turbines with ratings from 3 to 10 MW. Comparisons between the SIPMG and rotor-surface-mounted permanent magnet synchronous generator (PMSG) show that the SIPMGs have about 120% torque density and 78% cost per...

Preparation of samples for leaf architecture studies, a method for mounting cleared leaves1

Science.gov (United States)

Vasco, Alejandra; Thadeo, Marcela; Conover, Margaret; Daly, Douglas C.

2014-01-01

• Premise of the study: Several recent waves of interest in leaf architecture have shown an expanding range of approaches and applications across a number of disciplines. Despite this increased interest, examination of existing archives of cleared and mounted leaves shows that current methods for mounting, in particular, yield unsatisfactory results and deterioration of samples over relatively short periods. Although techniques for clearing and staining leaves are numerous, published techniques for mounting leaves are scarce. • Methods and Results: Here we present a complete protocol and recommendations for clearing, staining, and imaging leaves, and, most importantly, a method to permanently mount cleared leaves. • Conclusions: The mounting protocol is faster than other methods, inexpensive, and straightforward; moreover, it yields clear and permanent samples that can easily be imaged, scanned, and stored. Specimens mounted with this method preserve well, with leaves that were mounted more than 35 years ago showing no signs of bubbling or discoloration. PMID:25225627

Coupling slots without shunt impedance drop

International Nuclear Information System (INIS)

Balleyguier, P.

1996-01-01

It is well known that coupling slots between adjacent cells in a π-mode structure reduce shunt impedance per unit length with respect to single cell cavities. To design optimized coupling slots, one has to answer the following question: for a given coupling factor, what shape, dimension, position and number of slots lead to the lowest shunt impedance drop? A numerical study using the 3D code MAFIA has been carried out. The aim was to design the 352 MHz cavities for the high intensity proton accelerator of the TRISPAL project. The result is an unexpected set of four 'petal' slots. Such slots should lead to a quasi-negligible drop in shunt impedance: about -1% on average, for particle velocity from 0.4 c to 0.8 c. (author)

Study on the high-frequency laser measurement of slot surface difference

Science.gov (United States)

Bing, Jia; Lv, Qiongying; Cao, Guohua

2017-10-01

In view of the measurement of the slot surface difference in the large-scale mechanical assembly process, Based on high frequency laser scanning technology and laser detection imaging principle, This paragraph designs a double galvanometer pulse laser scanning system. Laser probe scanning system architecture consists of three parts: laser ranging part, mechanical scanning part, data acquisition and processing part. The part of laser range uses high-frequency laser range finder to measure the distance information of the target shape and get a lot of point cloud data. Mechanical scanning part includes high-speed rotary table, high-speed transit and related structure design, in order to realize the whole system should be carried out in accordance with the design of scanning path on the target three-dimensional laser scanning. Data processing part mainly by FPGA hardware with LAbVIEW software to design a core, to process the point cloud data collected by the laser range finder at the high-speed and fitting calculation of point cloud data, to establish a three-dimensional model of the target, so laser scanning imaging is realized.

Slot-Coupled Barbel Antenna

DEFF Research Database (Denmark)

Jørgensen, Kasper Lüthje; Jakobsen, Kaj Bjarne

2016-01-01

A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant.......A novel slot-coupled barbel antenna is designed and analyzed. A sensitivity analysis performed in order to improve the bandwidth, while the center frequency is kept constant....

Optical Slot-Waveguide Based Biochemical Sensors

Directory of Open Access Journals (Sweden)

Carlos Angulo Barrios

2009-06-01

Full Text Available Slot-waveguides allow light to be guided and strongly confined inside a nanometer-scale region of low refractive index. Thus stronger light-analyte interaction can be obtained as compared to that achievable by a conventional waveguide, in which the propagating beam is confined to the high-refractive-index core of the waveguide. In addition, slot-waveguides can be fabricated by employing CMOS compatible materials and technology, enabling miniaturization, integration with electronic, photonic and fluidic components in a chip, and mass production. These advantages have made the use of slot-waveguides for highly sensitive biochemical optical integrated sensors an emerging field. In this paper, recent achievements in slot-waveguide based biochemical sensing will be reviewed. These include slot-waveguide ring resonator based refractometric label-free biosensors, label-based optical sensing, and nano-opto-mechanical sensors.

PV module mounting method and mounting assembly

Science.gov (United States)

Lenox, Carl J.S.; Johnson, Kurt M.

2013-04-23

A method for mounting PV modules to a deck includes selecting PV module layout pattern so that adjacent PV module edges are spaced apart. PV mounting and support assemblies are secured to the deck according to the layout pattern using fasteners extending into the deck. The PV modules are placed on the PV mounting and support assemblies. Retaining elements are located over and secured against the upper peripheral edge surfaces of the PV modules so to secure them to the deck with the peripheral edges of the PV modules spaced apart from the deck. In some examples a PV module mounting assembly, for use on a shingled deck, comprises flashing, a base mountable on the flashing, a deck-penetrating fastener engageable with the base and securable to the deck so to secure the flashing and the base to the shingled deck, and PV module mounting hardware securable to the base.

Burnout and distribution of liquid between the flow core and wall films in narrow slot channels

Science.gov (United States)

Boltenko, E. A.; Shpakovskii, A. A.

2010-03-01

Previous works on studying distribution of liquid between the flow core and wall films in narrow slot channels are briefly reviewed. Interrelation between mass transfer processes and burnout is shown. A procedure for calculating burnout on convex and concave heat-transfer surfaces in narrow slot channels is presented.

Force prediction in permanent magnet flat linear motors (abstract)

International Nuclear Information System (INIS)

Eastham, J.F.; Akmese, R.

1991-01-01

The advent of neodymium iron boron rare-earth permanent magnet material has afforded the opportunity to construct linear machines of high force to weight ratio. The paper describes the design and construction of an axial flux machine and rotating drum test rig. The machine occupies an arc of 45 degree on a drum 1.22 m in diameter. The excitation is provided by blocks of NdFeB material which are skewed in order to minimize the force variations due to slotting. The stator carries a three-phase short-chorded double-layer winding of four poles. The machine is supplied by a PWM inverter the fundamental component of which is phase locked to the rotor position so that a ''dc brushless'' drive system is produced. Electromagnetic forces including ripple forces are measured at supply frequencies up to 100 Hz. They are compared with finite-element analysis which calculates the force variation over the time period. The paper then considers some of the causes of ripple torque. In particular, the force production due solely to the permanent magnet excitation is considered. This has two important components each acting along the line of motion of the machine, one is due to slotting and the other is due to the finite length of the primary. In the practical machine the excitation poles are skewed to minimize the slotting force and the effectiveness of this is confirmed by both results from the experiments and the finite-element analysis. The end effect force is shown to have a space period of twice that of the excitation. The amplitude of this force and its period are again confirmed by practical results

Magnetically nonlinear dynamic model of synchronous motor with permanent magnets

International Nuclear Information System (INIS)

Hadziselimovic, Miralem; Stumberger, Gorazd; Stumberger, Bojan; Zagradisnik, Ivan

2007-01-01

This paper deals with a magnetically nonlinear two-axis dynamic model of a permanent magnet synchronous motor (PMSM). The geometrical and material properties of iron core and permanent magnets, the effects of winding distribution, saturation, cross-saturation and slotting effects are, for the first time, simultaneously accounted for in a single two-axis dynamic model of a three-phase PMSM. They are accounted for by current- and position-dependent characteristics of flux linkages. These characteristics can be determined either experimentally or by the finite element (FE) computations. The results obtained by the proposed dynamic model show a very good agreement with the measured ones and those obtained by the FE computation

Analytical Calculation of the Magnetic Field distribution in a Flux-Modulated Permanent-Magnet Brushless Motor

DEFF Research Database (Denmark)

Zhang, Xiaoxu; Liu, Xiao; Chen, Zhe

2015-01-01

This paper presents a rapid approach to compute the magnetic field distribution in a flux-modulated permanent-magnet brushless motor. Partial differential equations are used to describe the magnet field behavior in terms of magnetic vector potentials. The whole computational domain is divided...... into several regions, i.e., magnet, air-gaps, slot-openings, and slots. The numerical solution could be obtained by applying the boundary constraints on the interfaces between these regions. The accuracy of the proposed analytical model is verified by comparing the no-load magnetic field and armature reaction...... magnetic field with those calculated by finite element method....

Design of large permanent magnetized synchronous electric machines: Low speed, high torque machines - generator for direct driven wind turbine - motor for rim driven thruster

Energy Technology Data Exchange (ETDEWEB)

Kroevel, Oeystein

2011-02-15

This work presents the design of two prototype permanent magnetized electric machines for two different applications where large permanent magnet machines might be used. Existing technology have been used as the fundament for new design and adapted to new applications, contributing, hopefully, to the development of better and more environmental friendly energy conversion. The first application presented is represented with a prototype made in cooperation with the industry in which a PM-motor is integrated into a propeller unit. Both because of the industrial connection, and the integration between the PM-motor and the propeller, the choices made for the PM-motor are conservative trying to reduce the risk. The direct rim driven thruster prototype includes a surface mounted radial flux permanent magnet machine (SM RFPM) with fractional slot winding with a q around 1. Other engineering features were introduced to make the integration of propeller and motor feasible, but without the PM-machine the thruster would not have reached the performance demand. An important part of the project was to show that the SM RFPM enables this solution, providing high performance with a large air gap. The prototype has been tested in sea, under harsh conditions, and even though the magnets have been exposed directly to sea water and been visible corroded, the electric motor still performs well within the specifications. The second application is represented with a prototype PM-generator for wind turbines. This is an example of a new, very low speed high torque machine. The generator is built to test phenomena regarding concentrated coils, and as opposed to the first application, being a pure academic university project, its success is not connected to its performance, but with the prototype's ability to expose the phenomena in question. The prototype, or laboratory model, of the generator for direct driven wind turbines features SM RFPM with concentrated coils (CC). An opportunity

Floating Chip Mounting System Driven by Repulsive Force of Permanent Magnets for Multiple On-Site SPR Immunoassay Measurements

Science.gov (United States)

Horiuchi, Tsutomu; Tobita, Tatsuya; Miura, Toru; Iwasaki, Yuzuru; Seyama, Michiko; Inoue, Suzuyo; Takahashi, Jun-ichi; Haga, Tsuneyuki; Tamechika, Emi

2012-01-01

We have developed a measurement chip installation/removal mechanism for a surface plasmon resonance (SPR) immunoassay analysis instrument designed for frequent testing, which requires a rapid and easy technique for changing chips. The key components of the mechanism are refractive index matching gel coated on the rear of the SPR chip and a float that presses the chip down. The refractive index matching gel made it possible to optically couple the chip and the prism of the SPR instrument easily via elastic deformation with no air bubbles. The float has an autonomous attitude control function that keeps the chip parallel in relation to the SPR instrument by employing the repulsive force of permanent magnets between the float and a float guide located in the SPR instrument. This function is realized by balancing the upward elastic force of the gel and the downward force of the float, which experiences a leveling force from the float guide. This system makes it possible to start an SPR measurement immediately after chip installation and to remove the chip immediately after the measurement with a simple and easy method that does not require any fine adjustment. Our sensor chip, which we installed using this mounting system, successfully performed an immunoassay measurement on a model antigen (spiked human-IgG) in a model real sample (non-homogenized milk) that included many kinds of interfering foreign substances without any sample pre-treatment. The ease of the chip installation/removal operation and simple measurement procedure are suitable for frequent on-site agricultural, environmental and medical testing. PMID:23202030

Slot deformation of various stainless steel bracket due to the torque force of the beta-titanium wire

Science.gov (United States)

Huda, M. M.; Siregar, E.; Ismah, N.

2017-08-01

Stainless steel bracket slot deformation ffects the force applied to teeth and it can impede tooth movement and prolong orthodontic treatment time. The aim of this study is to determine the slot deformation due to torque of a 0.021 × 0.025 inch Beta Titanium wire with a torsional angle of 30° and 45° for five different bracket brands: y, 3M, Biom, Versadent, Ormco, and Shinye. The research also aims to compare the deformation and amount of torque among all five bracket brands at torsional angles of 30° and 45°. Fifty stainless steel edgewise brackets from the five bracket group brands (n=10) were attached to acrylic plates. The bracket slot measurements were carried out in two stages. In the first stage, the, deformation was measured by calculating the average bracket slot height using a stereoscopy microscope before and after application of torque. In the second stage, the torque was measured using a torque measurement apparatus. The statistical analysis shows that slot deformations were found on all five bracket brands with a clinical permanent deformation on the Biom (2.79 μm) and Shinye (2.29 μm) brackets. The most torque was observed on the 3M bracket, followed by the Ormco, Versadent, Shinye, and Biom brackets. When the brands were compared, a correlation between bracket slot deformation and the amount of torque was found, but the correlation was not statistically significant for the 3M and Ormco brackets and the Biom and Shinye brackets. There is a difference in the amount of torque between the five brands with a torsional angle of 30° (except the 3M and Ormco brackets) and those with a torsional angle of 45°. The composition of the metal and the manufacturing process are the factors that influence the occurrence of bracket slot deformation and the amount of torque. A manufacturing process using metal injection molding (MIM) and metal compositions of AISI 303 and 17-4 PH stainless steel reduce the risk of deformation.

MHD-flow in slotted channels with conducting walls

International Nuclear Information System (INIS)

Evtushenko, I.A.; Kirillov, I.R.; Reed, C.B.

1994-07-01

A review of experimental results is presented for magnetohydrodynamic (MHD) flow in rectangular channels with conducting walls and high aspect ratios (longer side parallel to the applied magnetic field), which are called slotted channels. The slotted channel concept was conceived at Efremov Institute as a method for reducing MHD pressure drop in liquid metal cooled blanket design. The experiments conducted by the authors were aimed at studying both fully developed MHD-flow, and the effect of a magnetic field on the hydrodynamics of 3-D flows in slotted channels. Tests were carried out on five models of the slotted geometry. A good agreement between test and theoretical results for the pressure drop in slotted channels was demonstrated. Application of a open-quotes one-electrode movable probeclose quotes for velocity measurement permitted measurement of the M-shape velocity profiles in the slotted channels. Suppression of 3-D inertial effects in slotted channels of complex geometry was demonstrated based on potential distribution data

Pumping slots: impedances and power losses

Energy Technology Data Exchange (ETDEWEB)

Kurennoy, S [Maryland Univ., College Park, MD (United States). Dept. of Physics

1996-08-01

Contributions of pumping slots to the beam coupling impedances and power losses in a B-factory ring are considered. While their leading contribution is to the inductive impedance, for high-intensity machines with short bunches like e{sup +}e{sup -} B-factories the real part of the impedance and related loss factors are also important. Using an analytical approach we calculate the coupling impedances and loss factors due to slots in a ring with an arbitrary cross section of the vacuum chamber. Effects of the slot tilt on the beam impedance are also considered, and restrictions on the tilt angle are derived from limitations on the impedance increase. The power leakage through the slots is discussed briefly. The results are applied to the KEK B-factory. (author)

A High-gain and Low-scattering Waveguide Slot Antenna of Artificial Magnetic Conductor Octagonal Ring Arrangement

Directory of Open Access Journals (Sweden)

X. Liu

2016-04-01

Full Text Available A novel design of high-gain and low-scattering waveguide slot antenna is proposed in this paper. Firstly the scattering pattern of artificial magnetic conductor (AMC composite surface is estimated by array factor analysis method. The comparison between octagonal ring arrangement and chessboard arrangement proves that the former arrangement has the characteristic of diffuseness-like and expands the bandwidth of radar cross section (RCS reduction. Secondly, the metal surface of waveguide slot antenna (WSA is replaced by the octagonal ring arrangement composite surface (ORACS. The gain is improved because of spurious radiation units which are around the slot. At the same time using the phase cancellation principle, a backscatter null achieves RCS reduction in the vertical direction. Experimental results show that the novel antenna after loading with the ORACS, the gain is improved by 5dB; the bandwidth of RCS reduction (reduction greater than 10dB is 5.24-5.92 GHz.

Permanent magnet machine with windings having strand transposition

Science.gov (United States)

Qu, Ronghai; Jansen, Patrick Lee

2009-04-21

This document discusses, among other things, a stator with transposition between the windings or coils. The coils are free from transposition to increase the fill factor of the stator slots. The transposition at the end connections between an inner coil and an outer coil provide transposition to reduce circulating current loss. The increased fill factor reduces further current losses. Such a stator is used in a dual rotor, permanent magnet machine, for example, in a compressor pump, wind turbine gearbox, wind turbine rotor.

Changes in the surface roughness and friction coefficient of orthodontic bracket slots before and after treatment.

Science.gov (United States)

Liu, Xiaomo; Lin, Jiuxiang; Ding, Peng

2013-01-01

In this study, we tested the surface roughness of bracket slots and the friction coefficient between the bracket and the stainless steel archwire before and after orthodontic treatment. There were four experimental groups: groups 1 and 2 were 3M new and retrieved brackets, respectively, and groups 3 and 4 were BioQuick new and retrieved brackets, respectively. All retrieved brackets were taken from patients with the first premolar extraction and using sliding mechanics to close the extraction space. The surface roughness of specimens was evaluated using an optical interferometry profilometer, which is faster and nondestructive compared with a stylus profilometer, and provided a larger field, needing no sample preparation, compared with atomic force microscopy. Orthodontic treatment resulted in significant increases in surface roughness and coefficient of friction for both brands of brackets. However, there was no significant difference by brand for new or retrieved brackets. These retrieval analysis results highlight the necessity of reevaluating the properties and clinical behavior of brackets during treatment to make appropriate treatment decisions. © Wiley Periodicals, Inc.

Student-Led Objective Tutorial (SLOT) in Medical Education.

Science.gov (United States)

Sivagnanam, Gurusamy; Saraswathi, Simansalam; Rajasekaran, Aiyalu

2006-12-01

Purpose - To assess an innovative tutoring program named 'Student-Led Objective Tutorial' (SLOT) among undergraduate medical students. Method - The program was conceptualized by the Pharmacology Unit of Faculty of Medicine and Health Sciences, Asian Institute of Medicine Science & Technology (AIMST), Malaysia and implemented in the middle of 2005. A cohort of 246 medical undergraduate students (spread across 5 consecutive batches) participated. Following a brief explanation on the purpose and nature of SLOT, each batch was divided into small groups and was given a reading assignment on 4 previously delivered lecture topics. Each group was asked to prepare 3-5 multiple choice questions (MCQs) of their own in PowerPoint format to be presented, in turns, to the whole class on the day of SLOT. The proceedings were facilitated by 2 lecturers. Student feedback on the efficacy and benefits were assessed through an anonymous self administered questionnaire. Results - About 76% (188) of the students favored SLOT. The acceptance rate of SLOT was higher among males. There was no significant difference between batches in their opinions on whether to pursue SLOT in future. The most prevalent positive comment was that SLOT enhanced learning skills, and the negative comment being, it consumed more time. Conclusions - SLOT is a novel tutorial method which can offset faculty shortage with advantages like enhanced interest among teachers and learners, uniform reach of content, opportunities for group learning, and involvement of visual aids as teaching-learning (T-L) method. SLOT unraveled the students' potential of peer tutoring both inside as well as outside the classroom. Consumer tutors (students) can be tapped as a resource for SLOT for all subjects and courses in healthcare teaching.

Flush Mounting Of Thin-Film Sensors

Science.gov (United States)

Moore, Thomas C., Sr.

1992-01-01

Technique developed for mounting thin-film sensors flush with surfaces like aerodynamic surfaces of aircraft, which often have compound curvatures. Sensor mounted in recess by use of vacuum pad and materials selected for specific application. Technique involves use of materials tailored to thermal properties of substrate in which sensor mounted. Together with customized materials, enables flush mounting of thin-film sensors in most situations in which recesses for sensors provided. Useful in both aircraft and automotive industries.

Slotting allowances to coordinate manufacturers’ retail sales effort

OpenAIRE

Foros, Øystein; Kind, Hans Jarle; Sand, Jan Yngve

2007-01-01

Slotting allowances are fees paid by manufacturers to get access to retailers’ shelf space. Although the main attention towards slotting allowances has been within the grocery industry, slotting allowances have also been applied within e.g. e-commerce and mobile telephony. In these industries we observe that distributors have large market power due to their control of access to customers. We analyse how shifting bargaining power from manufacturers to retailers and the use of slotting allowanc...

The impact of accelerometer mounting methods on the level of vibrations recorded at ground surface

Directory of Open Access Journals (Sweden)

Krzysztof Czech

2014-08-01

Full Text Available The paper presents the results of field research based on the measurements of accelerations recorded at ground surface. The source of the vibration characterized by high repetition rate of pulse parameters was light falling weight deflectometer ZFG-01. Measurements of vibrations have been carried out using top quality high-precision measuring system produced by Brüel&Kiær. Accelerometers were mounted on a sandy soil surface at the measuring points located radially at 5-m and 10-m distances from the source of vibration. The paper analyses the impact that the method of mounting accelerometers on the ground has on the level of the recorded values of accelerations of vibrations. It has been shown that the method of attaching the sensor to the surface of the ground is crucial for the credibility of the performed measurements.[b]Keywords[/b]: geotechnics, surface vibrations, ground, vibration measurement

A new method for the design of slot antenna arrays: Theory and experiment

KAUST Repository

Clauzier, Sebastien

2016-04-10

The present paper proposes and validates a new general design methodology that can be used to automatically find proper positions and orientations of waveguide-based radiating slots capable of realizing any given radiation beam profile. The new technique combines basic radiation theory and waveguide propagation theory in a novel analytical model that allows the prediction of the radiation characteristics of generic slots without the need to perform full-wave numerical solution. The analytical model is then used to implement a low-cost objective function within a global optimization scheme (here genetic algorithm.) The algorithm is then deployed to find optimum positions and orientations of clusters of radiating slots cut into the waveguide surface such that any desired beam pattern can be obtained. The method is verified using both full-wave numerical solution and experiment.

Body surface mounted biomedical monitoring system using Bluetooth.

Science.gov (United States)

Nambu, Masayuki

2007-01-01

Continuous monitoring in daily life is important for the health condition control of the elderly. However, portable or wearable devices need to carry by user on their own will. On the other hand, implantation sensors are not adoptable, because of generic users dislike to insert the any object in the body for monitoring. Therefore, another monitoring system of the health condition to carry it easily is necessary. In addition, ID system is necessary even if the subject live with few families. Furthermore, every measurement system should be wireless system, because not to obstruct the daily life of the user. In this paper, we propose the monitoring system, which is mounted on the body surface. This system will not obstruct the action or behavior of user in daily life, because this system attached the body surface on the back of the user. In addition, this system has wireless communication system, using Bluetooth, and acquired data transfer to the outside of the house via the Internet.

Design of an Electric Commutated Frog-Leg Winding Permanent-Magnet DC Machine

Directory of Open Access Journals (Sweden)

Hang Zhang

2014-03-01

Full Text Available An electric commutated frog-leg winding permanent-magnet (PM DC machine is proposed in this paper. It has a semi-closed slotted stator with a classical type of mesh winding introduced from the conventional brushed DC machine and a polyphase electric commutation besides a PM excitation rotor and a circular arrayed Hall position sensor. Under the cooperation between the position sensor and the electric commutation, the proposed machine is basically operated on the same principle of the brushed one. Because of its simplex frog-leg winding, the combination between poles and slots is designed as 4/22, and the number of phases is set as 11. By applying an exact analytical method, which is verified comparable with the finite element analyses (FEA, to the prediction of its instantaneous magnetic field, electromotive force (EMF, cogging torque and output torque, it is well designed with a series of parameters in dimension aiming at the lowest cogging torque. A 230 W, 4-pole, and 22-slot new machine is prototyped and tested to verify the analysis.

Multiple-Objective Particle Swarm Optimization for Multi-Head Beam-Type Surface Mounting Machines

NARCIS (Netherlands)

Torabi, S.A.; Hamedi, M.; Ashayeri, J.

2010-01-01

The growing demand for electronic devices has made the manufacturing of printed circuit boards (PCBs) a promising industry over the last decades. As the demand for printed circuit boards increases, the industry becomes more dependent on highly automated assembly processes using Surface Mounting

Multiphysics modelling and simulation of dry laser cleaning of micro-slots with particle contaminants

International Nuclear Information System (INIS)

Yue Liyang; Wang Zengbo; Li Lin

2012-01-01

Light could interact differently with thin-film contaminants and particle contaminates because of their different surface morphologies. In the case of dry laser cleaning of small transparent particles, it is well known that particles could function like mini-lenses, causing a localized near-field hot spot effect on the cleaning process. This paper looks into a special, yet important, phenomenon of dry laser cleaning of particles trapped in micro-sized slots. The effects of slot size, particle size and particle aggregate states in the cleaning process have been theoretically investigated, based on a coupled electromagnetic-thermal-mechanical multiphysics modelling and simulation approach. The study is important for the development and optimization of laser cleaning processes for contamination removal from cracks and slots. (paper)

A Novel Dual-Permanent-Magnet-Excited Machine with Flux Strengthening Effect for Low-Speed Large-Torque Applications

Directory of Open Access Journals (Sweden)

Yujun Shi

2018-01-01

Full Text Available This paper proposes a novel dual-permanent-magnet-excited (DPME machine. It employs two sets of permanent magnets (PMs. One is on the rotor, the other is on the stator with PM arrays. When compared with the existing DPME machines, not all of the PMs are located in the slots formed by the iron teeth. Specifically, the radially magnetized PMs in the arrays are located under the short iron teeth, while the tangentially magnetized PMs are located in the slots formed by the long stator iron teeth and the radially magnetized PMs. Each long stator iron tooth is sandwiched by two tangentially magnetized PMs with opposite directions, thus resulting in the flux strengthening effect. The simulation analysis indicates that the proposed machine can offer large back EMF with low THD and large torque density with low torque ripple when compared with Machine I from a literature. Meanwhile, by comparison, the proposed machine has great potential in improving the power factor and efficiency.

Stereoscopic display in a slot machine

Science.gov (United States)

Laakso, M.

2012-03-01

This paper reports the results of a user trial with a slot machine equipped with a stereoscopic display. The main research question was to find out what kind of added value does stereoscopic 3D (S-3D) bring to slot games? After a thorough literature survey, a novel gaming platform was designed and implemented. Existing multi-game slot machine "Nova" was converted to "3DNova" by replacing the monitor with an S-3D display and converting six original games to S-3D format. To evaluate the system, several 3DNova machines were put available for players for four months. Both qualitative and quantitative analysis was carried out from statistical values, questionnaires and observations. According to the results, people find the S-3D concept interesting but the technology is not optimal yet. Young adults and adults were fascinated by the system, older people were more cautious. Especially the need to wear stereoscopic glasses provide a challenge; ultimate system would probably use autostereoscopic technology. Also the games should be designed to utilize its full power. The main contributions of this paper are lessons learned from creating an S-3D slot machine platform and novel information about human factors related to stereoscopic slot machine gaming.

Dual Mode Slotted Monopole Antenna

Science.gov (United States)

2017-01-05

May 2017 The below identified patent application is available for licensing. Requests for information should be addressed to: TECHNOLOGY...REFERENCE TO OTHER PATENT APPLICATIONS [0002] None. BACKGROUND OF THE INVENTION (1) Field of the Invention [0003] The present invention is directed...to connect across slot 14. [0005] In United States Patent No. 6,127,983 to Rivera and Josypenko, it has been shown that the slotted cylinder

Speed Sensorless Control of Permanent Magnet Synchronous Motors in Mine Electric Locomotive Drive

Directory of Open Access Journals (Sweden)

Yudong LI

2014-04-01

Full Text Available This paper presents a novel sensorless control method of permanent magnet synchronous motors a low speed based on a high-frequency voltage signal injection. The approach superimposes a persistent HF voltage signal into the estimated d-axis to get the rotor position error angle-related signal by detecting the corresponding voltage response and current response. Then the rotor position and motor speed are obtained. Theoretical analysis and simulation results demonstrate that the approach can achieve sensorless control of permanent magnet synchronous motors at zero and low speed, ensure good dynamic and static performances, and achieve effective control when applied to servo system. Finally, a test prototype system which used a digital signal processor and space vector pulse width modulation technology has been developed. Experimental results show that the system has better static, the effectiveness and dynamic performance of the adaptive test signals in a sensorless controlled surface-mounted permanent magnet synchronous machines.

S-parameters for weakly excited slots

DEFF Research Database (Denmark)

Albertsen, Niels Christian

1999-01-01

A simple approach to account for parasitic effects in weakly excited slots cut in the broad wall of a rectangular waveguide is proposed......A simple approach to account for parasitic effects in weakly excited slots cut in the broad wall of a rectangular waveguide is proposed...

Slot Machine Response Frequency Predicts Pathological Gambling

DEFF Research Database (Denmark)

Linnet, Jakob; Rømer Thomsen, Kristine; Møller, Arne

2013-01-01

Slot machines are among the most addictive forms of gambling, and pathological gambling slot machine players represent the largest group of treatment seekers, accounting for 35% to 93% of the population. Pathological gambling sufferers have significantly higher response frequency (games / time......) on slot machines compared with non-problem gamblers, which may suggest increased reinforcement of the gambling behavior in pathological gambling. However, to date it is unknown whether or not the increased response frequency in pathological gambling is associated with symptom severity of the disorder....... This study tested the hypothesis that response frequency is associated with symptom severity in pathological gambling. We tested response frequency among twenty-two pathological gambling sufferers and twenty-one non-problem gamblers on a commercially available slot machine, and screened for pathological...

Geometry optimization of five-phase permanent magnet synchronous motors using Bees algorithm

Directory of Open Access Journals (Sweden)

R Ilka

2015-12-01

Full Text Available Among all types of electrical motors, permanent magnet synchronous motors (PMSMs are reliable and efficient motors in industrial applications. Because of their superiority over other kinds of motors, they are replacing conventional electric motors. On the other hand, high-phase PMSMs are good candidates to be used in certain industrial and military projects such as electric vehicles, spacecrafts, naval systems and etc. In these cases, the motor has to be designed with minimum volume and high torque and efficiency. Design optimization can improve their features noticeably, thus reduce volume and enhance performance of motors. In this paper, a new method for optimum design of a five-phase surface-mounted permanent magnet synchronous motor is presented to achieve minimum permanent magnets (PMs volume with an increased torque and efficiency. Design optimization is performed in search for optimum dimensions of the motor and its permanent magnets using Bees Algorithm (BA. The design optimization results in a motor with great improvement regarding the original motor which is compared with two well-known evolutionary algorithms i.e. GA and PSO. Finally, finite element method simulation is utilized to validate the accuracy of the design.

Genome-wide association studies of pit-and-fissure- and smooth-surface caries in permanent dentition.

Science.gov (United States)

Zeng, Z; Shaffer, J R; Wang, X; Feingold, E; Weeks, D E; Lee, M; Cuenco, K T; Wendell, S K; Weyant, R J; Crout, R; McNeil, D W; Marazita, M L

2013-05-01

While genetics clearly influences dental caries risk, few caries genes have been discovered and validated. Recent studies have suggested differential genetic factors for primary dentition caries and permanent dentition caries, as well as for pit-and-fissure- (PF) and smooth- (SM) surface caries. We performed separate GWAS for caries in permanent-dentition PF surfaces (1,017 participants, adjusted for age, sex, and the presence of Streptococcus mutans) and SM surfaces (1,004 participants, adjusted for age, education group, and the presence of Streptococcus mutans) in self-reported whites (ages 14 to 56 yrs). Caries scores were derived based on visual assessment of each surface of each tooth; more than 1.2 million SNPs were either successfully genotyped or imputed and were tested for association. Two homologous genes were suggestively associated: BCOR (Xp11.4) in PF-surface caries (p value = 1.8E-7), and BCORL1 (Xq26.1) in SM-surface caries (p value = 1.0E-5). BCOR mutations cause oculofaciocardiodental syndrome, a Mendelian disease involving multiple dental anomalies. Associations of other plausible cariogenesis genes were also observed for PF-surface caries (e.g., INHBA, p value = 6.5E-6) and for SM-surface caries (e.g., CXCR1 and CXCR2, p value = 1.9E-6). This study supports the notion that genes differentially affect cariogenesis across the surfaces of the permanent dentition, and nominates several novel genes for investigation.

Investigation of Permanent Magnet Demagnetization in Synchronous Machines during Multiple Short-Circuit Fault Conditions

Directory of Open Access Journals (Sweden)

Stefan Sjökvist

2017-10-01

Full Text Available Faults in electrical machines can vary in severity and affect different parts of the machine. This study focuses on various kinds of short-circuits on the terminal side of a generic 20 kW surface mounted permanent magnet synchronous generator and how successive faults affect the performance of the machine. The study was conducted with the commercially available finite element method software COMSOL Multiphysics ® , and two time-dependent models for demagnetization of permanent magnets were compared, one using only internal models and the other using a proprietary external function. The study is simulation based and the two models were compared to a previously experimentally verified stationary model. Results showed that the power output decreased by more than 30% after five successive faults. In addition, the no-load voltage had become unsymmetrical, which was explained by the uneven demagnetization of the permanent magnets. The permanent magnet with the lowest reduction in average remanence was decreased by 0.8%, while the highest average reduction was 23.8% in another permanent magnet. The internal simulation model was about four times faster than the external model, but slightly overestimated the demagnetization.

Housing And Mounting Structure

Science.gov (United States)

Anderson, Gene R.; Armendariz, Marcelino G.; Baca, Johnny R.F.; Bryan, Robert P.; Carson, Richard F.; Duckett, III, Edwin B.; McCormick, Frederick B.; Miller, Gregory V.; Peterson, David W.; Smith, Terrance T.

2005-03-08

This invention relates to an optical transmitter, receiver or transceiver module, and more particularly, to an apparatus for connecting a first optical connector to a second optical connector. The apparatus comprises: (1) a housing having at least a first end and at least a second end, the first end of the housing capable of receiving the first optical connector, and the second end of the housing capable of receiving the second optical connector; (2) a longitudinal cavity extending from the first end of the housing to the second end of the housing; and (3) an electromagnetic shield comprising at least a portion of the housing. This invention also relates to an apparatus for housing a flexible printed circuit board, and this apparatus comprises: (1) a mounting structure having at least a first surface and a second surface; (2) alignment ridges along the first and second surfaces of the mounting structure, the alignment ridges functioning to align and secure a flexible printed circuit board that is wrapped around and attached to the first and second surfaces of the mounting structure; and (3) a series of heat sink ridges adapted to the mounting structure, the heat sink ridges functioning to dissipate heat that is generated from the flexible printed circuit board.

CFD Analysis of a Centrifugal Fan for Performance Enhancement using Converging Boundary Layer Suction Slots

OpenAIRE

K. Vasudeva Karanth; N. Yagnesh Sharma

2009-01-01

Generally flow behavior in centrifugal fan is observed to be in a state of instability with flow separation zones on suction surface as well as near the front shroud. Overall performance of the diffusion process in a centrifugal fan could be enhanced by judiciously introducing the boundary layer suction slots. With easy accessibility of CFD as an analytical tool, an extensive numerical whole field analysis of the effect of boundary layer suction slots in discrete regions ...

Vibration attenuation and shape control of surface mounted, embedded smart beam

Directory of Open Access Journals (Sweden)

Vivek Rathi

Full Text Available Active Vibration Control (AVC using smart structure is used to reduce the vibration of a system by automatic modification of the system structural response. AVC is widely used, because of its wide and broad frequency response range, low additional mass, high adaptability and good efficiency. A lot of research has been done on Finite Element (FE models for AVC based on Euler Bernoulli Beam Theory (EBT. In the present work Timoshenko Beam Theory (TBT is used to model a smart cantilever beam with surface mounted sensors / actuators. A Periodic Output Feedback (POF Controller has been designed and applied to control the first three modes of vibration of a flexible smart cantilever beam. The difficulties encountered in the usage of surface mounted piezoelectric patches in practical situations can be overcome by the use of embedded shear sensors / actuators. A mathematical model of a smart cantilever beam with embedded shear sensors and actuators is developed. A POF Controller has been designed and applied to control of vibration of a flexible smart cantilever beam and effect of actuator location on the performance of the controller is investigated. The mathematical modeling and control of a Multiple Input multiple Output (MIMO systems with two sensors and two actuators have also been considered.

Effect of Slotted Anode on Gas Bubble Behaviors in Aluminum Reduction Cell

Science.gov (United States)

Sun, Meijia; Li, Baokuan; Li, Linmin; Wang, Qiang; Peng, Jianping; Wang, Yaowu; Cheung, Sherman C. P.

2017-12-01

In the aluminum reduction cells, gas bubbles are generated at the bottom of the anode which eventually reduces the effective current contact area and the system efficiency. To encourage the removal of gas bubbles, slotted anode has been proposed and increasingly adopted by some industrial aluminum reduction cells. Nonetheless, the exact gas bubble removal mechanisms are yet to be fully understood. A three-dimensional (3D) transient, multiphase flow mathematical model coupled with magnetohydrodynamics has been developed to investigate the effect of slotted anode on the gas bubble movement. The Eulerian volume of fluid approach is applied to track the electrolyte (bath)-molten aluminum (metal) interface. Meanwhile, the Lagrangian discrete particle model is employed to handle the dynamics of gas bubbles with considerations of the buoyancy force, drag force, virtual mass force, and pressure gradient force. The gas bubble coalescence process is also taken into account based on the O'Rourke's algorithm. The two-way coupling between discrete bubbles and fluids is achieved by the inter-phase momentum exchange. Numerical predictions are validated against the anode current variation in an industrial test. Comparing the results using slotted anode with the traditional one, the time-averaged gas bubble removal rate increases from 36 to 63 pct; confirming that the slotted anode provides more escaping ways and shortens the trajectories for gas bubbles. Furthermore, the slotted anode also reduces gas bubble's residence time and the probability of coalescence. Moreover, the bubble layer thickness in aluminum cell with slotted anode is reduced about 3.5 mm (17.4 pct), so the resistance can be cut down for the sake of energy saving and the metal surface fluctuation amplitude is significantly reduced for the stable operation due to the slighter perturbation with smaller bubbles.

Vertically Polarized Omnidirectional Printed Slot Loop Antenna

DEFF Research Database (Denmark)

Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren H.; Thaysen, Jesper

2015-01-01

A novel vertically polarized omnidirectional printed slot loop antenna has been designed, simulated, fabricated and measured. The slot loop works as a magnetic loop. The loop is loaded with inductors to insure uniform and in-phase fields in the slot in order to obtain an omnidirectional radiation...... pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due to the polarization....

Energy dissipation of slot-type flip buckets

Science.gov (United States)

Wu, Jian-hua; Li, Shu-fang; Ma, Fei

2018-03-01

The energy dissipation is a key index in the evaluation of energy dissipation elements. In the present work, a flip bucket with a slot, called the slot-type flip bucket, is theoretically and experimentally investigated by the method of estimating the energy dissipation. The theoretical analysis shows that, in order to have the energy dissipation, it is necessary to determine the sequent flow depth h 1 and the flow speed V 1 at the corresponding position through the flow depth h 2 after the hydraulic jump. The relative flow depth h 2 / h 。 is a function of the approach flow Froude number Fr 。, the relative slot width b/B 。, and the relative slot angle θ/β. The expression for estimating the energy dissipation is developed, and the maximum error is not larger than 9.21%.

Surface topography characterization using an atomic force microscope mounted on a coordinate measuring machine

DEFF Research Database (Denmark)

De Chiffre, Leonardo; Hansen, H.N; Kofod, N

1999-01-01

The paper describes the construction, testing and use of an integrated system for topographic characterization of fine surfaces on parts having relatively big dimensions. An atomic force microscope (AFM) was mounted on a manual three-coordinate measuring machine (CMM) achieving free positioning o...

49 CFR 236.809 - Signal, slotted mechanical.

Science.gov (United States)

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Signal, slotted mechanical. 236.809 Section 236.809 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... § 236.809 Signal, slotted mechanical. A mechanically operated signal with an electromagnetic device...

Modeling of vibrations isolation and arrest by shape memory parts and permanent magnets

Science.gov (United States)

Belyaev, Fedor S.; Volkov, Aleksandr E.; Evard, Margarita E.; Vikulenkov, Andrey V.; Uspenskiy, Evgeniy S.

2018-05-01

A vibration protection system under consideration consists of a payload connected to a vibrating housing by shape memory alloy (SMA) slotted springs. To provide an arrest function two permanent magnets are inserted into the system. The slotted SMA elements are preliminary deformed in the martensitic state. Activation of one element by heating initiates force and displacement generation, which provide an arrest of the payload by magnets. The magnets also secure the arrest mode after cooling of the SMA element. Activation of the other element results in uncaging of the payload and switching to the vibration isolation mode. Computer simulations of arrest and uncaging when the housing is quiescent or producing sine-wave displacements were carried out. Functional-mechanical behavior of SMA parts was described by means of a microstructural model.

A Waveguide Transverse Broad Wall Slot Radiating Between Baffles

DEFF Research Database (Denmark)

Dich, Mikael; Rengarajan, S.R.

1997-01-01

An analysis of the self impedance of waveguide-fed transverse slots radiating between baffles is presented. The region exterior to the slot is treated as a parallel plate (PP) waveguide which radiates into half space through an aperture in an infinite ground plane. The slot problem is analyzed...

Optoelectronic Mounting Structure

Science.gov (United States)

Anderson, Gene R.; Armendariz, Marcelino G.; Baca, Johnny R. F.; Bryan, Robert P.; Carson, Richard F.; Chu, Dahwey; Duckett, III, Edwin B.; McCormick, Frederick B.; Peterson, David W.; Peterson, Gary D.; Reber, Cathleen A.; Reysen, Bill H.

2004-10-05

An optoelectronic mounting structure is provided that may be used in conjunction with an optical transmitter, receiver or transceiver module. The mounting structure may be a flexible printed circuit board. Thermal vias or heat pipes in the head region may transmit heat from the mounting structure to the heat spreader. The heat spreader may provide mechanical rigidity or stiffness to the heat region. In another embodiment, an electrical contact and ground plane may pass along a surface of the head region so as to provide an electrical contact path to the optoelectronic devices and limit electromagnetic interference. In yet another embodiment, a window may be formed in the head region of the mounting structure so as to provide access to the heat spreader. Optoelectronic devices may be adapted to the heat spreader in such a manner that the devices are accessible through the window in the mounting structure.

Assessing and Mapping of Road Surface Roughness based on GPS and Accelerometer Sensors on Bicycle-Mounted Smartphones

Science.gov (United States)

Shen, Jie; Wan, Mi; Shi, Jiafeng

2018-01-01

The surface roughness of roads is an essential road characteristic. Due to the employed carrying platforms (which are often cars), existing measuring methods can only be used for motorable roads. Until now, there has been no effective method for measuring the surface roughness of un-motorable roads, such as pedestrian and bicycle lanes. This hinders many applications related to pedestrians, cyclists and wheelchair users. In recognizing these research gaps, this paper proposes a method for measuring the surface roughness of pedestrian and bicycle lanes based on Global Positioning System (GPS) and accelerometer sensors on bicycle-mounted smartphones. We focus on the International Roughness Index (IRI), as it is the most widely used index for measuring road surface roughness. Specifically, we analyzed a computing model of road surface roughness, derived its parameters with GPS and accelerometers on bicycle-mounted smartphones, and proposed an algorithm to recognize potholes/humps on roads. As a proof of concept, we implemented the proposed method in a mobile application. Three experiments were designed to evaluate the proposed method. The results of the experiments show that the IRI values measured by the proposed method were strongly and positively correlated with those measured by professional instruments. Meanwhile, the proposed algorithm was able to recognize the potholes/humps that the bicycle passed. The proposed method is useful for measuring the surface roughness of roads that are not accessible for professional instruments, such as pedestrian and cycle lanes. This work enables us to further study the feasibility of crowdsourcing road surface roughness with bicycle-mounted smartphones. PMID:29562731

Rectangular-cladding silicon slot waveguide with improved nonlinear performance

Science.gov (United States)

Huang, Zengzhi; Huang, Qingzhong; Wang, Yi; Xia, Jinsong

2018-04-01

Silicon slot waveguides have great potential in hybrid silicon integration to realize nonlinear optical applications. We propose a rectangular-cladding hybrid silicon slot waveguide. Simulation result shows that, with a rectangular-cladding, the slot waveguide can be formed by narrower silicon strips, so the two-photon absorption (TPA) loss in silicon is decreased. When the cladding material is a nonlinear polymer, the calculated TPA figure of merit (FOMTPA) is 4.4, close to the value of bulk nonlinear polymer of 5.0. This value confirms the good nonlinear performance of rectangular-cladding silicon slot waveguides.

Safety effects of permanent running lights for bicycles

DEFF Research Database (Denmark)

Madsen, Jens Chr. Overgaard; Andersen, T.; Lahrmann, Harry

2013-01-01

Making the use of daytime running lights mandatory for motor vehicles is generally documented to have had a positive impact upon traffic safety. Improving traffic safety for bicyclists is a focal point in the road traffic safety work in Denmark. In 2004 and 2005 a controlled experiment including...... 3845 cyclists was carried out in Odense, Denmark in order to examine, if permanent running lights mounted to bicycles would improve traffic safety for cyclists. The permanent running lights were mounted to 1845 bicycles and the accident rate was recorded through 12 months for this treatment group...... and 2000 other bicyclists, the latter serving as a control group without bicycle running lights. The safety effect of the running lights is analysed by comparing incidence rates – number of bicycle accidents recorded per man-month – for the treatment group and the control group. The incidence rate...

Ultra-Broad Band Radar Cross Section Reduction of Waveguide Slot Antenna with Metamaterials

Directory of Open Access Journals (Sweden)

Qiang Fu

2016-06-01

Full Text Available To reduce the radar cross section of a waveguide slot antenna, a three-layer metamaterial is presented based on orthogonal double split-ring resonators. The absorption characteristics of three-layer metamaterial are demonstrated by simulation. Moreover, the metamaterials have been loaded on common waveguide slot antenna according to the surface current distribution. The ultra-broad band radar cross section reduction of the antenna with metamaterials had been theoretically and experimentally investigated by radiating and scattering performances. Experimental and simulated results showed that the proposed antenna with metamaterials performed broadband radar cross section reduction from 3.9 GHz to 18 GHz and the gain had been improved due to the coupling effect between slot and the period structure. The maximal radar cross section reduction achieved 17.81 dB at 8.68 GHz for x-polarized incidence and 21.79 dB at 6.25 GHz for y-polarized waves.

Slot Optimization Design of Induction Motor for Electric Vehicle

Science.gov (United States)

Shen, Yiming; Zhu, Changqing; Wang, Xiuhe

2018-01-01

Slot design of induction motor has a great influence on its performance. The RMxprt module based on magnetic circuit method can be used to analyze the influence of rotor slot type on motor characteristics and optimize slot parameters. In this paper, the authors take an induction motor of electric vehicle for a typical example. The first step of the design is to optimize the rotor slot by RMxprt, and then compare the main performance of the motor before and after the optimization through Ansoft Maxwell 2D. After that, the combination of optimum slot type and the optimum parameters are obtained. The results show that the power factor and the starting torque of the optimized motor have been improved significantly. Furthermore, the electric vehicle works at a better running status after the optimization.

Predictors of return rate discrimination in slot machine play.

Science.gov (United States)

Coates, Ewan; Blaszczynski, Alex

2014-09-01

The purpose of this study was to investigate the extent to which accurate estimates of payback percentages and volatility combined with prior learning, enabled players to successfully discriminate between multi-line/multi-credit slot machines that provided differing rates of reinforcement. The aim was to determine if the capacity to discriminate structural characteristics of gaming machines influenced player choices in selecting 'favourite' slot machines. Slot machine gambling history, gambling beliefs and knowledge, impulsivity, illusions of control, and problem solving style were assessed in a sample of 48 first year undergraduate psychology students. Participants were subsequently exposed to a choice paradigm where they could freely select to play either of two concurrently presented PC-simulated slot machines programmed to randomly differ in expected player return rates (payback percentage) and win frequency (volatility). Results suggest that prior learning and cognitions (particularly gambler's fallacy) but not payback, were major contributors to the ability of a player to discriminate volatility between slot machines. Participants displayed a general tendency to discriminate payback, but counter-intuitively placed more bets on the slot machine with lower payback percentage rates.

The Role of Auditory Features Within Slot-Themed Social Casino Games and Online Slot Machine Games.

Science.gov (United States)

Bramley, Stephanie; Gainsbury, Sally M

2015-12-01

Over the last few years playing social casino games has become a popular entertainment activity. Social casino games are offered via social media platforms and mobile apps and resemble gambling activities. However, social casino games are not classified as gambling as they can be played for free, outcomes may not be determined by chance, and players receive no monetary payouts. Social casino games appear to be somewhat similar to online gambling activities in terms of their visual and auditory features, but to date little research has investigated the cross over between these games. This study examines the auditory features of slot-themed social casino games and online slot machine games using a case study design. An example of each game type was played on three separate occasions during which, the auditory features (i.e., music, speech, sound effects, and the absence of sound) within the games were logged. The online slot-themed game was played in demo mode. This is the first study to provide a qualitative account of the role of auditory features within a slot-themed social casino game and an online slot machine game. Our results found many similarities between how sound is utilised within the two games. Therefore the sounds within these games may serve functions including: setting the scene for gaming, creating an image, demarcating space, interacting with visual features, prompting players to act, communicating achievements to players, providing reinforcement, heightening player emotions and the gaming experience. As a result this may reduce the ability of players to make a clear distinction between these two activities, which may facilitate migration between games.

DNS of Turbulent Flow and Heat Transfer in a Channel with Surface Mounted Cubes

NARCIS (Netherlands)

Verstappen, R.W.C.P.; Velde, R.M. van der; Veldman, A.E.P.

2000-01-01

The turbulent flow and heat transfer in a channel with surface mounted cubical obstacles forms a generic example of a problem that occurs in many engineering applications, for instance in the design of cooling devices. We have performed a numerical simulation of it without using any turbulence

DNS of turbulent flow and heat transfer in a channel with surface mounted cubes

NARCIS (Netherlands)

Verstappen, R.W.C.P.; Velde, R.M. van der; Veldman, A.E.P.

2000-01-01

The turbulent flow and heat transfer in a channel with surface mounted cubical obstacles forms a generic example of a problem that occurs in many engineering applications, for instance in the design of cooling devices. We have performed a numerical simulation of it without using any turbulence

Assembling surface mounted components on ink-jet printed double sided paper circuit board

International Nuclear Information System (INIS)

Andersson, Henrik A; Manuilskiy, Anatoliy; Haller, Stefan; Sidén, Johan; Nilsson, Hans-Erik; Hummelgård, Magnus; Olin, Håkan; Hummelgård, Christine

2014-01-01

Printed electronics is a rapidly developing field where many components can already be manufactured on flexible substrates by printing or by other high speed manufacturing methods. However, the functionality of even the most inexpensive microcontroller or other integrated circuit is, at the present time and for the foreseeable future, out of reach by means of fully printed components. Therefore, it is of interest to investigate hybrid printed electronics, where regular electrical components are mounted on flexible substrates to achieve high functionality at a low cost. Moreover, the use of paper as a substrate for printed electronics is of growing interest because it is an environmentally friendly and renewable material and is, additionally, the main material used for many packages in which electronics functionalities could be integrated. One of the challenges for such hybrid printed electronics is the mounting of the components and the interconnection between layers on flexible substrates with printed conductive tracks that should provide as low a resistance as possible while still being able to be used in a high speed manufacturing process. In this article, several conductive adhesives are evaluated as well as soldering for mounting surface mounted components on a paper circuit board with ink-jet printed tracks and, in addition, a double sided Arduino compatible circuit board is manufactured and programmed. (paper)

Assembling surface mounted components on ink-jet printed double sided paper circuit board.

Science.gov (United States)

Andersson, Henrik A; Manuilskiy, Anatoliy; Haller, Stefan; Hummelgård, Magnus; Sidén, Johan; Hummelgård, Christine; Olin, Håkan; Nilsson, Hans-Erik

2014-03-07

Printed electronics is a rapidly developing field where many components can already be manufactured on flexible substrates by printing or by other high speed manufacturing methods. However, the functionality of even the most inexpensive microcontroller or other integrated circuit is, at the present time and for the foreseeable future, out of reach by means of fully printed components. Therefore, it is of interest to investigate hybrid printed electronics, where regular electrical components are mounted on flexible substrates to achieve high functionality at a low cost. Moreover, the use of paper as a substrate for printed electronics is of growing interest because it is an environmentally friendly and renewable material and is, additionally, the main material used for many packages in which electronics functionalities could be integrated. One of the challenges for such hybrid printed electronics is the mounting of the components and the interconnection between layers on flexible substrates with printed conductive tracks that should provide as low a resistance as possible while still being able to be used in a high speed manufacturing process. In this article, several conductive adhesives are evaluated as well as soldering for mounting surface mounted components on a paper circuit board with ink-jet printed tracks and, in addition, a double sided Arduino compatible circuit board is manufactured and programmed.

Assembling surface mounted components on ink-jet printed double sided paper circuit board

Energy Technology Data Exchange (ETDEWEB)

Andersson, Henrik A; Manuilskiy, Anatoliy; Haller, Stefan; Sidén, Johan; Nilsson, Hans-Erik [Department of Electronics Design, Mid Sweden University, SE-851 70 Sundsvall (Sweden); Hummelgård, Magnus; Olin, Håkan [Department of Natural Science, Mid Sweden University, SE-851 70 Sundsvall (Sweden); Hummelgård, Christine [Acreo Swedish ICT AB, Håstaholmen 4, SE-824 42 Hudiksvall (Sweden)

2014-03-07

Printed electronics is a rapidly developing field where many components can already be manufactured on flexible substrates by printing or by other high speed manufacturing methods. However, the functionality of even the most inexpensive microcontroller or other integrated circuit is, at the present time and for the foreseeable future, out of reach by means of fully printed components. Therefore, it is of interest to investigate hybrid printed electronics, where regular electrical components are mounted on flexible substrates to achieve high functionality at a low cost. Moreover, the use of paper as a substrate for printed electronics is of growing interest because it is an environmentally friendly and renewable material and is, additionally, the main material used for many packages in which electronics functionalities could be integrated. One of the challenges for such hybrid printed electronics is the mounting of the components and the interconnection between layers on flexible substrates with printed conductive tracks that should provide as low a resistance as possible while still being able to be used in a high speed manufacturing process. In this article, several conductive adhesives are evaluated as well as soldering for mounting surface mounted components on a paper circuit board with ink-jet printed tracks and, in addition, a double sided Arduino compatible circuit board is manufactured and programmed. (paper)

Effect of accelerated ageing and surface sealing on the permanent deformation of auto-polymerising soft linings.

Science.gov (United States)

da Silva, Joaquim; Takahashi, Jessica; Nuňez, Juliana; Consani, Rafael; Mesquita, Marcelo

2012-09-01

To compare the effects of different ageing methods on the permanent deformation of two permanent soft liners. The materials selected were auto-polymerising acrylic resin and silicone-based reliners. Sealer coating was also evaluated. Sixty specimens of each reliner were manufactured (12.7 mm diameter and 19 mm length). Specimens were randomly distributed into 12 groups (n = 10) and submitted to one of the accelerated ageing processes. Permanent deformation tests were conducted with a mechanical device described within the American Dental Association specification number 18 with a compressive load of 750 gf applied for 30 s. All data were submitted for statistical analysis. Mann-Whitney test compared the effect of the surface sealer on each material and the permanent deformation of the materials in the same ageing group (p = 0.05). Kruskal-Wallis and Dunn tests compared all ageing groups of each material (p = 0.05). The silicone-based reliner presented a lower permanent deformation than the acrylic resin-based reliner, regardless of the ageing procedure. The surface sealer coating was effective only for the thermocycled silicone group and the accelerated ageing processes affected only the permanent deformation of the acrylic resin-based material. The silicone-based reliner presented superior elastic properties and the thermocycling was more effective in ageing the materials. © 2010 The Gerodontology Society and John Wiley & Sons A/S.

[Influence of slot size on torque control].

Science.gov (United States)

Tian, Jun; Liu, Zhong-Hao; Zhang, Ding; Wu, Chuan-Jun

2009-12-01

To study the influence of two slot size brackets on torque control when teeth interacted in the same arch. After the upper arch was aligned and leveled in Typodont study, the inclinations of upper teeth 5 +/- 5 were measured when 0.457 2 mm x 0.635 0 mm OPA-K brackets and 0.558 8 mmx0.711 2 mm OPA-K brackets were filled with 0.431 8 mm x 0.635 0 mm stainless steel wire. This experiment was duplicated 10 times. The inclin of each tooth were transformed to the absolute values of the torque play angle psi by computing program, and paired-t test was used. The two kinds of slot size brackets were different with statistical significance on torque control. When the brackets were filled with 0.431 8 mm x 0.635 0 mm stainless steel wire, the absolute values of the angle psi in 0.558 8 mm x 0.711 2 mm and 0.457 2 mm x 0.635 0 mm slot size brackets were 6.140 degrees +/- 3.758 degrees and 2.608 degrees +/- 1.479 degrees respectively, and the average difference of that between the two slot size brackets was 3.532 degrees. The absolute values of the angle psi in the upper left and right canine brackets were 2.560 degrees +/- 2.605 degrees, 4.230 degrees +/- 2.817 degrees, 1.260 degrees +/- 0.747 degrees and 2.070 degrees +/- 0.663 degrees respectively, and average differences between them were smaller than that in the other teeth. There was difference between the two kinds of slot size brackets on torque control, and 0.457 2 mm x 0.635 0 mm slot size bracket controls torque better when filled with the same size wire. In this study, the teeth interaction in the same arch probably caused the result that the difference of two slot size brackets on torque control was less than the study results of the theory calculations and material studys before.

The Gambling Reducing Slot Machine

DEFF Research Database (Denmark)

Callesen, Mette Buhl; Thomsen, Kristine Rømer; Linnet, Jakob

2007-01-01

  The Gambling Reducing Slot Machine - Preliminary results Mette Buhl Callesen, Kristine Rømer Thomsen, Jakob Linnet and Arne Møller The PET Centre, Aarhus University Hospital and Centre of Functionally Integrative Neuroscience, Aarhus, Denmark   Slot machines are among the most addictive forms...... and willingness to continue gambling. The results may have important implications for understanding how to reduce gambling behavior in pathological gamblers.   [1] Griffiths, M. 1999. Gambling Technologies: Prospects for Problem Gambling. Journal of Gambling Studies, vol. 15(3), pp. 265-283.    ...

Design and production of a new surface mount charge-integrating amplifier for CDF

Energy Technology Data Exchange (ETDEWEB)

Nelson, C.; Drake, G.

1991-12-31

We present our experiences in designing and producing 26,000 new charge-integrating amplifiers for CDF, using surface-mount components. The new amplifiers were needed to instrument 920 new 24-channel CDF RABBIT boards, which are replacing an older design rendered obsolete by increases in the collision rate. Important design considerations were frequency response, physical size and cost. 5 refs.

Design and production of a new surface mount charge-integrating amplifier for CDF

International Nuclear Information System (INIS)

Nelson, C.; Drake, G.

1991-01-01

We present our experiences in designing and producing 26,000 new charge-integrating amplifiers for CDF, using surface-mount components. The new amplifiers were needed to instrument 920 new 24-channel CDF RABBIT boards, which are replacing an older design rendered obsolete by increases in the collision rate. Important design considerations were frequency response, physical size and cost. 5 refs

Theory of a Traveling Wave Feed for a Planar Slot Array Antenna

Science.gov (United States)

Rengarajan, Sembiam

2012-01-01

Planar arrays of waveguide-fed slots have been employed in many radar and remote sensing applications. Such arrays are designed in the standing wave configuration because of high efficiency. Traveling wave arrays can produce greater bandwidth at the expense of efficiency due to power loss in the load or loads. Traveling wave planar slot arrays may be designed with a long feed waveguide consisting of centered-inclined coupling slots. The feed waveguide is terminated in a matched load, and the element spacing in the feed waveguide is chosen to produce a beam squinted from the broadside. The traveling wave planar slot array consists of a long feed waveguide containing resonant-centered inclined coupling slots in the broad wall, coupling power into an array of stacked radiating waveguides orthogonal to it. The radiating waveguides consist of longitudinal offset radiating slots in a standing wave configuration. For the traveling wave feed of a planar slot array, one has to design the tilt angle and length of each coupling slot such that the amplitude and phase of excitation of each radiating waveguide are close to the desired values. The coupling slot spacing is chosen for an appropriate beam squint. Scattering matrix parameters of resonant coupling slots are used in the design process to produce appropriate excitations of radiating waveguides with constraints placed only on amplitudes. Since the radiating slots in each radiating waveguide are designed to produce a certain total admittance, the scattering (S) matrix of each coupling slot is reduced to a 2x2 matrix. Elements of each 2x2 S-matrix and the amount of coupling into the corresponding radiating waveguide are expressed in terms of the element S11. S matrices are converted into transmission (T) matrices, and the T matrices are multiplied to cascade the coupling slots and waveguide sections, starting from the load end and proceeding towards the source. While the use of non-resonant coupling slots may provide an

Radiation from a Slot System in the Coaxial Line Shield

Science.gov (United States)

Katrich, V. A.; Lyashchenko, V. A.; Medvedev, N. V.

2012-06-01

The problem of electromagnetic wave excitation, scattering and radiation by the system of transverse slots, cut in the outer conductor of an infinite coaxial line, is solved by the magnetomotive forces method. The radiation and reflection coefficients of the circular and arc slot systems are investigated in dependence on slot sizes and feeder parameters. The processes of radiation into lossy material media are studied. The researches have been carried out with the interconnection between slots of internal and external regions considered.

Investigation of a slot nanoantenna in optical frequency range

Science.gov (United States)

Dinesh kumar, V.; Asakawa, Kiyoshi

2009-11-01

Following the analogy of radio frequency slot antenna and its complementary dipole, we propose the implementation of a slot nanoantenna (SNA) in the optical frequency range. Using finite-difference time-domain (FDTD) method, we investigate the electromagnetic (EM) properties of a SNA formed in a thin gold film and compare the results with the properties of a gold dipole nanoantenna (DNA) of the same dimension as the slot. It is found that the response of the SNA is very similar to the DNA, like their counterparts in the radio frequency (RF) range. The SNA can enhance the near field intensity of incident field which strongly depends on its feedgap dimension. The resonance of the SNA is influenced by its slot length; for the increasing slot length, resonant frequency decreases whereas the sharpness of resonance increases. Besides, the resonance of the SNA is found sensitive to the thickness of metal film, when the latter is smaller than the skin depth. The effect of polarization of incident field on the EM response of the SNA was examined; the field enhancement is optimum when polarization is parallel to the feedgap. Finally, we calculate the radiation patterns of the DNA and SNA and compare them with those of the RF dipole antenna. The radiation pattern of the SNA is found to be independent of its slot length when excited at resonant frequency. To the best of our knowledge, this is the first study on a slot antenna in the optical frequency.

Metal membrane with dimer slots as a universal polarizer

Science.gov (United States)

Zhukovsky, Sergej; Zalkovskij, Maksim; Malureanu, Radu; Kremers, Christian; Chigrin, Dmitry; Tang, Peter T.; Jepsen, Peter U.; Lavrinenko, Andrei V.

2014-03-01

In this work, we show theoretically and confirm experimentally that thin metal membranes patterned with an array of slot dimers (or their Babinet analogue with metal rods) can function as a versatile spectral and polarization filter. We present a detailed covariant multipole theory for the electromagnetic response of an arbitrary dimer based on the Green functions approach. The theory confirms that a great variety of polarization properties, such as birefringence, chirality and elliptical dichroism, can be achieved in a metal layer with such slot-dimer patterning (i.e. in a metasurface). Optical properties of the metasurface can be extensively tuned by varying the geometry (shape and dimensions) of the dimer, for example, by adjusting the sizes and mutual placement of the slots (e.g. inter-slot distance and alignment angle). Three basic shapes of dimers are analyzed: II-shaped (parallel slots), V-shaped, and T-shaped. These particular shapes of dimers are found to be sensitive to variations of the slots lengths and orientation of elements. Theoretical results are well supported by full-wave three-dimensional simulations. Our findings were verified experimentally on the metal membranes fabricated using UV lithography with subsequent Ni growth. Such metasurfaces were characterized using time-domain THz spectroscopy. The samples exhibit pronounced optical activity (500 degrees per wavelength) and high transmission: even though the slots cover only 4.3 % of the total membrane area the amplitude transmission reaches 0.67 at the resonance frequency 0.56 THz.

Different optical properties in different periodic slot cavity geometrical morphologies

Science.gov (United States)

Zhou, Jing; Shen, Meng; Du, Lan; Deng, Caisong; Ni, Haibin; Wang, Ming

2016-09-01

In this paper, optical properties of two-dimensional periodic annular slot cavity arrays in hexagonal close-packing on a silica substrate are theoretically characterized by finite difference time domain (FDTD) simulation method. By simulating reflectance spectra, electric field distribution, and charge distribution, we confirm that multiple cylindrical surface plasmon resonances can be excited in annular inclined slot cavities by linearly polarized light, in which the four reflectance dips are attributed to Fabry-Perot cavity resonances in the coaxial cavity. A coaxial waveguide mode TE11 will exist in these annular cavities, and the wavelengths of these reflectance dips are effectively tailored by changing the geometrical pattern of slot cavity and the dielectric materials filled in the cavities. These resonant wavelengths are localized in annular cavities with large electric field enhancement and dissipate gradually due to metal loss. The formation of an absorption peak can be explained from the aspect of phase matching conditions. We observed that the proposed structure can be tuned over the broad spectral range of 600-4000 nm by changing the outer and inner radii of the annular gaps, gap surface topography. Meanwhile, different lengths of the cavity may cause the shift of resonance dips. Also, we study the field enhancement at different vertical locations of the slit. In addition, dielectric materials filling in the annular gaps will result in a shift of the resonance wavelengths, which make the annular cavities good candidates for refractive index sensors. The refractive index sensitivity of annular cavities can also be tuned by the geometry size and the media around the cavity. Annular cavities with novel applications can be implied as surface enhanced Raman spectra substrates, refractive index sensors, nano-lasers, and optical trappers. Project supported by the National Natural Science Foundation of China (Grant No. 61178044), the Natural Science Foundation

Humanizing machines: Anthropomorphization of slot machines increases gambling.

Science.gov (United States)

Riva, Paolo; Sacchi, Simona; Brambilla, Marco

2015-12-01

Do people gamble more on slot machines if they think that they are playing against humanlike minds rather than mathematical algorithms? Research has shown that people have a strong cognitive tendency to imbue humanlike mental states to nonhuman entities (i.e., anthropomorphism). The present research tested whether anthropomorphizing slot machines would increase gambling. Four studies manipulated slot machine anthropomorphization and found that exposing people to an anthropomorphized description of a slot machine increased gambling behavior and reduced gambling outcomes. Such findings emerged using tasks that focused on gambling behavior (Studies 1 to 3) as well as in experimental paradigms that included gambling outcomes (Studies 2 to 4). We found that gambling outcomes decrease because participants primed with the anthropomorphic slot machine gambled more (Study 4). Furthermore, we found that high-arousal positive emotions (e.g., feeling excited) played a role in the effect of anthropomorphism on gambling behavior (Studies 3 and 4). Our research indicates that the psychological process of gambling-machine anthropomorphism can be advantageous for the gaming industry; however, this may come at great expense for gamblers' (and their families') economic resources and psychological well-being. (c) 2015 APA, all rights reserved).

Slot Parameter Optimization for Multiband Antenna Performance Improvement Using Intelligent Systems

Directory of Open Access Journals (Sweden)

Erdem Demircioglu

2015-01-01

Full Text Available This paper discusses bandwidth enhancement for multiband microstrip patch antennas (MMPAs using symmetrical rectangular/square slots etched on the patch and the substrate properties. The slot parameters on MMPA are modeled using soft computing technique of artificial neural networks (ANN. To achieve the best ANN performance, Particle Swarm Optimization (PSO and Differential Evolution (DE are applied with ANN’s conventional training algorithm in optimization of the modeling performance. In this study, the slot parameters are assumed as slot distance to the radiating patch edge, slot width, and length. Bandwidth enhancement is applied to a formerly designed MMPA fed by a microstrip transmission line attached to the center pin of 50 ohm SMA connecter. The simulated antennas are fabricated and measured. Measurement results are utilized for training the artificial intelligence models. The ANN provides 98% model accuracy for rectangular slots and 97% for square slots; however, ANFIS offer 90% accuracy with lack of resonance frequency tracking.

Flexural and Thermal Properties of Novel Energy Conservation Slotted Reinforced Concrete Beams

Directory of Open Access Journals (Sweden)

Gao Ma

2016-01-01

Full Text Available Conventional solid reinforced concrete (RC beams were modified to slotted beams for consideration as thermal insulation structural components. The slotted beam consisted of an outer and an inner beam, respectively, with a slot located near the middle of the beam along its width direction for filling thermal insulation material. Flexural and thermal behavior of the slotted beams were investigated. Three RC reference solid beams and six slotted beams were fabricated and tested under four-point bending tests. The test results indicated that the failure mode of both slotted beams and the solid beams was flexural failure. However, the damage process of the slotted beams was different from that of the solid beams at the final loading stage. The moment curvature analysis indicated that the tensile reinforcement ratio of the outer and inner beams had an important effect on the flexural behavior, especially the ductility of the slotted beams. Thermal study indicated that the heat transfer coefficient of the slotted beam was greatly reduced and the thermal inertia factor increased a lot, compared with the solid beam. In addition, FE simulation results showed that a new frame structure using slotted beams exhibited obvious and attractive thermal insulation property.

Exact analytical modeling of magnetic vector potential in surface inset permanent magnet DC machines considering magnet segmentation

Science.gov (United States)

Jabbari, Ali

2018-01-01

Surface inset permanent magnet DC machine can be used as an alternative in automation systems due to their high efficiency and robustness. Magnet segmentation is a common technique in order to mitigate pulsating torque components in permanent magnet machines. An accurate computation of air-gap magnetic field distribution is necessary in order to calculate machine performance. An exact analytical method for magnetic vector potential calculation in surface inset permanent magnet machines considering magnet segmentation has been proposed in this paper. The analytical method is based on the resolution of Laplace and Poisson equations as well as Maxwell equation in polar coordinate by using sub-domain method. One of the main contributions of the paper is to derive an expression for the magnetic vector potential in the segmented PM region by using hyperbolic functions. The developed method is applied on the performance computation of two prototype surface inset magnet segmented motors with open circuit and on load conditions. The results of these models are validated through FEM method.

Dovetail Rotor Construction For Permanent-Magnet Motors

Science.gov (United States)

Kintz, Lawrence J., Jr.; Puskas, William J.

1988-01-01

New way of mounting magnets in permanent-magnet, electronically commutated, brushless dc motors. Magnets wedge shaped, tapering toward center of rotor. Oppositely tapered pole pieces, electron-beam welded to rotor hub, retain magnets against centrifugal force generated by spinning rotor. To avoid excessively long electron-beam welds, pole pieces assembled in segments rather than single long bars.

Label-free optical biosensing with slot-waveguides.

Science.gov (United States)

Barrios, Carlos A; Bañuls, María José; González-Pedro, Victoria; Gylfason, Kristinn B; Sánchez, Benito; Griol, Amadeu; Maquieira, A; Sohlström, H; Holgado, M; Casquel, R

2008-04-01

We demonstrate label-free molecule detection by using an integrated biosensor based on a Si(3)N(4)/SiO(2) slot-waveguide microring resonator. Bovine serum albumin (BSA) and anti-BSA molecular binding events on the sensor surface are monitored through the measurement of resonant wavelength shifts with varying biomolecule concentrations. The biosensor exhibited sensitivities of 1.8 and 3.2 nm/(ng/mm(2)) for the detection of anti-BSA and BSA, respectively. The estimated detection limits are 28 and 16 pg/mm(2) for anti-BSA and BSA, respectively, limited by wavelength resolution.

Preparation and mounting of adult Drosophila structures in Canada balsam.

Science.gov (United States)

Stern, David L; Sucena, Elio

2012-03-01

The Drosophila cuticle carries a rich array of morphological details. Thus, cuticle examination has had a central role in the history of genetics. To prepare fine "museum-quality," permanent slides, it is best to mount specimens in Canada Balsam. It is difficult to give precise recipes for Canada Balsam, because every user seems to prefer a slightly different viscosity. Dilute solutions spread easily and do not dry too rapidly while mounting specimens. The disadvantage is that there is actually less Balsam in a "drop" of the solution, and when dried, it can contract from the sides of the coverslip, sometimes disturbing the specimen. Unfortunately, there is no substitute for experience when using Canada Balsam. This protocol describes a procedure for mounting adult cuticles in Canada Balsam.

Nano-polarization-converter based on magnetic plasmon resonance excitation in an L-shaped slot antenna.

Science.gov (United States)

Yang, Jing; Zhang, Jiasen

2013-04-08

We propose a nano-polarization-converter made of a resonant L-shaped slot antenna in a gold film and study its optical properties using the finite-difference time-domain method. Phase retardation between the fast and slow axes of the nano-polarization-converter originates from the simultaneous excitation of both single-surface first-order magnetic plasmon resonance mode and second-order magnetic plasmon resonance mode at the working wavelength. By adjusting the size of the slot antenna, which is still much smaller than the wavelength, the working wavelength can be tuned within a large wavelength range.

Analysis and design of broadband U-slot cut rectangular microstrip ...

Indian Academy of Sciences (India)

AMIT A DESHMUKH

2017-07-15

Jul 15, 2017 ... Abstract. Broadband microstrip antenna using variations of U-slot has been widely reported. However, in most of the reported work, an in-depth explanation about the mode introduced by U-slot and procedure to design. U-slot cut antennas at any given frequency is not explained. In this paper, first an ...

Novel Sensorless Six-Step Communication Strategy for a Surface Permanent Magnet Synchronous Motor with DC Link Measurement

DEFF Research Database (Denmark)

Munteanu, A.; Agarlita, S. C.; Blaabjerg, Frede

2012-01-01

The present paper introduces a novel six-step commutation strategy for sensorless control applied for a surface permanent magnet synchronous motor that implies only dc link measurement (battery current and battery voltage). The control strategy makes use of a modified I-f starting procedure and t......-crossing of the back-emf are obtained from an observer that uses both current and battery voltage. The case study is represented by a surface permanent magnet synchronous motor prototype (6 /8 configuration), designed for the automotive air conditioning compressor drive....

Cogging torque optimization in surface-mounted permanent-magnet motors by using design of experiment

Energy Technology Data Exchange (ETDEWEB)

Abbaszadeh, K., E-mail: Abbaszadeh@kntu.ac.ir [Department of Electrical Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Rezaee Alam, F.; Saied, S.A. [Department of Electrical Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of)

2011-09-15

Graphical abstract: Magnet segment arrangement in cross section view of one pole for PM machine. Display Omitted Highlights: {yields} Magnet segmentation is an effective method for the cogging torque reduction. {yields} We have used the magnet segmentation method based on the design of experiment. {yields} We have used the RSM design of the design of experiment method. {yields} We have solved optimization via surrogate models like the polynomial regression. {yields} A significant reduction of the cogging torque is obtained by using RSM. - Abstract: One of the important challenges in design of the PM electrical machines is to reduce the cogging torque. In this paper, in order to reduce the cogging torque, a new method for designing of the motor magnets is introduced to optimize of a six pole BLDC motor by using design of experiment (DOE) method. In this method the machine magnets consist of several identical segments which are shifted to a definite angle from each other. Design of experiment (DOE) methodology is used for a screening of the design space and for the generation of approximation models using response surface techniques. In this paper, optimization is often solved via surrogate models, that is, through the construction of response surface models (RSM) like polynomial regression. The experiments were performed based on the response surface methodology (RSM), as a statistical design of experiment approach, in order to investigate the effect of parameters on the response variations. In this investigation, the optimal shifting angles (factors) were identified to minimize the cogging torque. A significant reduction of cogging torque can be achieved with this approach after only a few evaluations of the coupled FE model.

Cogging torque optimization in surface-mounted permanent-magnet motors by using design of experiment

International Nuclear Information System (INIS)

Abbaszadeh, K.; Rezaee Alam, F.; Saied, S.A.

2011-01-01

Graphical abstract: Magnet segment arrangement in cross section view of one pole for PM machine. Display Omitted Highlights: → Magnet segmentation is an effective method for the cogging torque reduction. → We have used the magnet segmentation method based on the design of experiment. → We have used the RSM design of the design of experiment method. → We have solved optimization via surrogate models like the polynomial regression. → A significant reduction of the cogging torque is obtained by using RSM. - Abstract: One of the important challenges in design of the PM electrical machines is to reduce the cogging torque. In this paper, in order to reduce the cogging torque, a new method for designing of the motor magnets is introduced to optimize of a six pole BLDC motor by using design of experiment (DOE) method. In this method the machine magnets consist of several identical segments which are shifted to a definite angle from each other. Design of experiment (DOE) methodology is used for a screening of the design space and for the generation of approximation models using response surface techniques. In this paper, optimization is often solved via surrogate models, that is, through the construction of response surface models (RSM) like polynomial regression. The experiments were performed based on the response surface methodology (RSM), as a statistical design of experiment approach, in order to investigate the effect of parameters on the response variations. In this investigation, the optimal shifting angles (factors) were identified to minimize the cogging torque. A significant reduction of cogging torque can be achieved with this approach after only a few evaluations of the coupled FE model.

Design of dual band FSS by using quadruple L-slot technique

Science.gov (United States)

Fauzi, Noor Azamiah Md; Aziz, Mohamad Zoinol Abidin Abd.; Said, Maizatul Alice Meor; Othman, Mohd Azlishah; Ahmad, Badrul Hisham; Malek, Mohd Fareq Abd

2015-05-01

This paper presents a new design of dual band frequency selective surface (FSS) for band pass microwave transmission application. FSS can be used on energy saving glass to improve the transmission of wireless communication signals through the glass. The microwave signal will be attenuate when propagate throughout the different structure such as building. Therefore, some of the wireless communication system cannot be used in the optimum performance. The aim of this paper is designed, simulated and analyzed the new dual band FSS structure for microwave transmission. This design is based on a quadruple L slot combined with cross slot to produce pass band at 900 MHz and 2.4 GHz. The vertical of pair inverse L slot is used as the band pass for the frequency of 2.4GHz. While, the horizontal of pair inverse L slot is used as the band pass at frequency 900MHz. This design is simulated and analyzed by using Computer Simulation Technology (CST) Microwave Studio (MWS) software. The characteristics of the transmission (S21) and reflection (S11) of the dual band FSS were simulater and analyzed. The bandwidth of the first band is 118.91MHz which covered the frequency range from 833.4MHz until 952.31MHz. Meanwhile, the bandwidth for the second band is 358.84MHz which covered the frequency range from 2.1475GHz until 2.5063GHz. The resonance/center frequency of this design is obtained at 900MHz with a 26.902dB return loss and 2.37GHz with 28.506dB a return loss. This FSS is suitable as microwave filter for GSM900 and WLAN 2.4GHz application.

Optimum Design of a Five-Phase Permanent Magnet Synchronous Motor for Underwater Vehicles by use of Particle Swarm Optimization

Directory of Open Access Journals (Sweden)

S. Asghar Gholamian

2012-12-01

Full Text Available Permanent magnet synchronous motors are efficient motors which have widespread applications in electric industry due to their noticeable features. One of the interesting applications of such motors is in underwater vehicles. In these cases, reaching to minimum volume and high torque of the motor are the major concern. Design optimization can enhance their merits considerably, thus reduce volume and improve performance of motors. In this paper, a new method for optimum design of a five-phase surface-mounted permanent magnet synchronous motor is presented to achieve minimum loss and magnet volume with an increased torque. A multi-objective optimization is performed in search for optimum dimensions of the motor and its permanent magnets using particle swarm optimization. The design optimization results in a motor with great improvement regarding the original motor. Finally, finite element analysis is utilized to validate the accuracy of the design.

Demonstration of slot-waveguide structures on silicon nitride / silicon oxide platform.

Science.gov (United States)

Barrios, C A; Sánchez, B; Gylfason, K B; Griol, A; Sohlström, H; Holgado, M; Casquel, R

2007-05-28

We report on the first demonstration of guiding light in vertical slot-waveguides on silicon nitride/silicon oxide material system. Integrated ring resonators and Fabry-Perot cavities have been fabricated and characterized in order to determine optical features of the slot-waveguides. Group index behavior evidences guiding and confinement in the low-index slot region at O-band (1260-1370nm) telecommunication wavelengths. Propagation losses of <20 dB/cm have been measured for the transverse-electric mode of the slot-waveguides.

Performance characteristics of solar air heater with surface mounted obstacles

International Nuclear Information System (INIS)

Bekele, Adisu; Mishra, Manish; Dutta, Sushanta

2014-01-01

Highlights: • Solar air heater with delta shaped obstacles have been studied. • Obstacle angle of incidence strongly affects the thermo-hydraulic performance. • Thermal performance of obstacle mounted collectors is superior to smooth collectors. • Thermo-hydraulic performance of the present SAH is higher than those in previous studies. - Abstract: The performance of conventional solar air heaters (SAHs) can be improved by providing obstacles on the heated wall (i.e. on the absorber plate). Experiments have been performed to collect heat transfer and flow-friction data from an air heater duct with delta-shaped obstacles mounted on the absorber surface and having an aspect ratio 6:1 resembling the conditions close to the solar air heaters. This study encompassed for the range of Reynolds number (Re) from 2100 to 30,000, relative obstacle height (e/H) from 0.25 to 0.75, relative obstacle longitudinal pitch (P l /e) from 3/2 to 11/2, relative obstacle transverse pitch (P t /b) from 1 to 7/3 and the angle of incidence (α) varied from 30° to 90°. The thermo-hydraulic performance characteristics of SAH have been compared with the previous published works and the optimum range of the geometries have been explored for the better performance of such air-heaters compared to the other designs of solar air heaters

FDTD Analysis of U-Slot Rectangular Patch Antenna

Science.gov (United States)

Luk, K. M.; Tong, K. F.; Shum, S. M.; Lee, K. F.; Lee, R. Q.

1997-01-01

The U-slot rectangular patch antenna (Figure I) has been found experimentally to provide impedance and gain bandwidths of about 300 without the need of stacked or coplanar parasitic elements [1,2]. In this paper, simulation results of the U-slot patch using FDTD analysis are presented. Comparison with measured results are given.

Sensor mount assemblies and sensor assemblies

Science.gov (United States)

Miller, David H [Redondo Beach, CA

2012-04-10

Sensor mount assemblies and sensor assemblies are provided. In an embodiment, by way of example only, a sensor mount assembly includes a busbar, a main body, a backing surface, and a first finger. The busbar has a first end and a second end. The main body is overmolded onto the busbar. The backing surface extends radially outwardly relative to the main body. The first finger extends axially from the backing surface, and the first finger has a first end, a second end, and a tooth. The first end of the first finger is disposed on the backing surface, and the tooth is formed on the second end of the first finger.

Mechanism Design for Multi-slot Ads Auction in Sponsored Search Markets

Science.gov (United States)

Deng, Xiaotie; Sun, Yang; Yin, Ming; Zhou, Yunhong

In this paper, we study pricing models for multi-slot advertisements, where advertisers can bid to place links to their sales webpages at one or multiple slots on a webpage, called the multi-slot AD auction problem. We develop and analyze several important mechanisms, including the VCG mechanism for multi-slot ads auction, the optimal social welfare solution, as well as two weighted GSP-like protocols (mixed and hybrid). Furthermore, we consider that forward-looking Nash equilibrium and prove its existence in the weighted GSP-like pricing protocols.

Wakes behind surface-mounted obstacles: Impact of aspect ratio, incident angle, and surface roughness

Science.gov (United States)

Tobin, Nicolas; Chamorro, Leonardo P.

2018-03-01

The so-called wake-moment coefficient C˜h and lateral wake deflection of three-dimensional windbreaks are explored in the near and far wake. Wind-tunnel experiments were performed to study the functional dependence of C˜h with windbreak aspect ratio, incidence angle, and the ratio of the windbreak height and surface roughness (h /z0 ). Supported with the data, we also propose basic models for the wake deflection of the windbreak in the near and far fields. The near-wake model is based on momentum conservation considering the drag on the windbreak, whereas the far-wake counterpart is based on existing models for wakes behind surface-mounted obstacles. Results show that C˜h does not change with windbreak aspect ratios of 10 or greater; however, it may be lower for an aspect ratio of 5. C˜h is found to change roughly with the cosine of the incidence angle, and to depend strongly on h /z0 . The data broadly support the proposed wake-deflection models, though better predictions could be made with improved knowledge of the windbreak drag coefficient.

Slotted Blades Savonius Wind Turbine Analysis by CFD

Directory of Open Access Journals (Sweden)

Andrea Alaimo

2013-12-01

Full Text Available In this paper a new bucket configuration for a Savonius wind generator is proposed. Numerical analyses are performed to estimate the performances of the proposed configuration by means of the commercial code COMSOL Multiphysics® with respect to Savonius wind turbine with overlap only. Parametric analyses are performed, for a fixed overlap ratio, by varying the slot position; the results show that for slot positioned near the blade root, the Savonius rotor improves performances at low tip speed ratio, evidencing a better starting torque. This circumstance is confirmed by static analyses performed on the slotted blades in order to investigate the starting characteristic of the proposed Savonius wind generator configuration.

Hall Current Plasma Source Having a Center-Mounted or a Surface-Mounted Cathode

Science.gov (United States)

Martinez, Rafael A. (Inventor); Williams, John D. (Inventor); Moritz, Jr., Joel A. (Inventor); Farnell, Casey C. (Inventor)

2018-01-01

A miniature Hall current plasma source apparatus having magnetic shielding of the walls from ionized plasma, an integrated discharge channel and gas distributor, an instant-start hollow cathode mounted to the plasma source, and an externally mounted keeper, is described. The apparatus offers advantages over other Hall current plasma sources having similar power levels, including: lower mass, longer lifetime, lower part count including fewer power supplies, and the ability to be continuously adjustable to lower average power levels using pulsed operation and adjustment of the pulse duty cycle. The Hall current plasma source can provide propulsion for small spacecraft that either do not have sufficient power to accommodate a propulsion system or do not have available volume to incorporate the larger propulsion systems currently available. The present low-power Hall current plasma source can be used to provide energetic ions to assist the deposition of thin films in plasma processing applications.

Slots in dielectric image line as mode launchers and circuit elements

Science.gov (United States)

Solbach, K.

1981-01-01

A planar resonator model is used to investigate slots in the ground plane of dielectric image lines. An equivalent circuit representation of the slot discontinuity is obtained, and the launching efficiency of the slot as a mode launcher is analyzed. Slots are also shown to be useful in the realization of dielectric image line array antennas. It is found that the slot discontinuity can be shown as a T-junction of the dielectric image line and a metal waveguide. The launching efficiency is found to increase with the dielectric constant of the dielectric image line, exhibiting a maximum value for guides whose height is slightly less than half a wavelength in the dielectric medium. The measured launching efficiencies of low permittivity dielectric image lines are found to be in good agreement with calculated values

Using wintergreen oil for mounting mosquito larvae: a safer alternative to xylene.

Science.gov (United States)

Koay, J B; Natasya, N N; Nashithatul, Mag; Ihsanuddin, R; Salleh, F M; Azil, A H

2016-01-01

Permanent mounting of fourth instar mosquito larvae is essential for identifying Aedes spp. This procedure requires extensive exposure to xylene, a clearing agent in the mounting process. We investigated wintergreen oil as a substitute for xylene. Five hundred larvae were mounted on slides to evaluate shrinkage or expansion of specimens after clearing using xylene or wintergreen oil. We examined the ventral brush and siphonal hair tufts for species identification and for preservation of morphological characteristics after clearing specimens in xylene or wintergreen oil. Shrinkage of the length of whole larvae and width of the head, thorax and abdomen after mounting was significantly greater after clearing with xylene than with wintergreen oil. The length of the comb scale nearest the ventral brush was similar for both clearing agents. The clarity of the specimens after mounting was improved by clearing with wintergreen oil, but the integrity of the ventral brush and siphonal hair tufts were similar for both clearing agents.

Comparison of static friction with self-ligating, modified slot design and conventional brackets

Directory of Open Access Journals (Sweden)

Raquel Morais Castro

2013-07-01

Full Text Available OBJECTIVE: To compare the static frictional forces generated at the bracket/wire interface of stainless steel brackets with different geometries and angulations, combined with orthodontic wires of different diameters. MATERIAL AND METHODS: The frictional forces were evaluated with three different types of metal brackets: a passive self-ligating (SmartClipTM, 3M/Unitek, Monrovia, USA, with a modified slot design (Mini Uni TwinTM, 3M/Unitek, Monrovia, USA and conventional (Kirium, Abzil, São José do Rio Preto, Brazil. The samples were mounted in a testing device with three different angulations and tested with 0.014" and 0.018" stainless steel wires (American Orthodontics, Sheboygan, USA. The static frictional force was measured using a universal testing machine (DL 500, EMIC®, São José dos Pinhais, Brazil with a crosshead speed of 1 mm/min. Statistical analysis was performed by two-way ANOVA followed by Bonferroni's post hoc test. RESULTS: There was a significant difference (p<0.05 in static friction when the three types of brackets were tested with the same wire size. The wire diameter influenced friction only when the brackets had a 10º angulation (p<0.05. The angulation influenced friction (p<0.05 when the brackets were associated with a 0.018" wire. CONCLUSION: Brackets with a modified slot design showed intermediate static frictional force values between the conventional and self-ligating brackets tested.

Discrete-Slots Models of Visual Working-Memory Response Times

Science.gov (United States)

Donkin, Christopher; Nosofsky, Robert M.; Gold, Jason M.; Shiffrin, Richard M.

2014-01-01

Much recent research has aimed to establish whether visual working memory (WM) is better characterized by a limited number of discrete all-or-none slots or by a continuous sharing of memory resources. To date, however, researchers have not considered the response-time (RT) predictions of discrete-slots versus shared-resources models. To complement the past research in this field, we formalize a family of mixed-state, discrete-slots models for explaining choice and RTs in tasks of visual WM change detection. In the tasks under investigation, a small set of visual items is presented, followed by a test item in 1 of the studied positions for which a change judgment must be made. According to the models, if the studied item in that position is retained in 1 of the discrete slots, then a memory-based evidence-accumulation process determines the choice and the RT; if the studied item in that position is missing, then a guessing-based accumulation process operates. Observed RT distributions are therefore theorized to arise as probabilistic mixtures of the memory-based and guessing distributions. We formalize an analogous set of continuous shared-resources models. The model classes are tested on individual subjects with both qualitative contrasts and quantitative fits to RT-distribution data. The discrete-slots models provide much better qualitative and quantitative accounts of the RT and choice data than do the shared-resources models, although there is some evidence for “slots plus resources” when memory set size is very small. PMID:24015956

Slotted Waveguide and Antenna Study for HPM and RF Applications

Science.gov (United States)

2017-07-25

conventional rectangular slot arrays. The proposed CSR-SW A provided higher peak gain than the conventional lambda /4 rectangu lar slot array and a...more compact s ize (55% size reductjon) compared to the lambda /2 rectangular slot array. Both the theoretic and measured results suggest a return loss...in terms of scattering matrix S is: (I-8) With the scattering matrix S, we can compute the scattering field at any position. The resonance of SCCR

Geothermal reservoirs. Position of slotted section of the tube casing

International Nuclear Information System (INIS)

Carotenuto, A.; Vanoli, L.; Casarosa, C.

1999-01-01

In the present work the authors have verified the influence of the position of slotted section casing on heat rate drawn by plants for exploitation of geothermal reservoirs that use heat exchangers placed at the bottom of the well (DHE). This study have been done modelling numerically the aquifer, by means of finite element method, evaluating the heat rate drawn by the heat exchanger at different position of the slotted section of the tube casing. Numerical calculations have allowed to show the influence of the main characteristics of the aquifer and of the main characteristics of the aquifer and of the plant on design of the slotted section of the tube casing. In particular, the authors have studied the influence of i) equivalent conductivity and permeability of the aquifer, ii) mass flow rate and the inlet and outlet aquifer temperature difference in the well, iii) the ratio between the length of the slotted section and the thickness of the geothermal layer, varying the position of the slotted section of the tube casing in the aquifer [it

Vertically Polarized Omnidirectional Printed Slot Loop AntennaPrinted Slot Loop Antenna (invited)

DEFF Research Database (Denmark)

Kammersgaard, Nikolaj Peter Iversen; Kvist, Søren Helstrup; Thaysen, Jesper

2015-01-01

and in-phase fields in the slot in order to obtain an omnidirectional radiation pattern. The antenna is designed for the 2.45 GHz Industrial, Scientific and Medical band. Applications of the antenna are many. One is for on-body applications since it is ideal for launching a creeping waves due...

Vision-Based Parking-Slot Detection: A Benchmark and A Learning-Based Approach

Directory of Open Access Journals (Sweden)

Lin Zhang

2018-03-01

Full Text Available Recent years have witnessed a growing interest in developing automatic parking systems in the field of intelligent vehicles. However, how to effectively and efficiently locating parking-slots using a vision-based system is still an unresolved issue. Even more seriously, there is no publicly available labeled benchmark dataset for tuning and testing parking-slot detection algorithms. In this paper, we attempt to fill the above-mentioned research gaps to some extent and our contributions are twofold. Firstly, to facilitate the study of vision-based parking-slot detection, a large-scale parking-slot image database is established. This database comprises 8600 surround-view images collected from typical indoor and outdoor parking sites. For each image in this database, the marking-points and parking-slots are carefully labeled. Such a database can serve as a benchmark to design and validate parking-slot detection algorithms. Secondly, a learning-based parking-slot detection approach, namely P S D L , is proposed. Using P S D L , given a surround-view image, the marking-points will be detected first and then the valid parking-slots can be inferred. The efficacy and efficiency of P S D L have been corroborated on our database. It is expected that P S D L can serve as a baseline when the other researchers develop more sophisticated methods.

A Comparison of the Accuracy of 0.022 Slots at Face, Base and Mesial and Distal Surface of Brackets marketed by Different Manufacturers

Directory of Open Access Journals (Sweden)

Karan Tangri

2012-01-01

Conclusion: The results of this study indicate that orthodontic bracket slots were different than stated by the manufacturers. All the brackets were larger at the face than at the base. Clinicians should be aware that there may be a three-dimensional loss of tooth positioning as a result of the inadvertent use of orthodontic brackets with inaccurate slots.

Methods and apparatus for radially compliant component mounting

Science.gov (United States)

Bulman, David Edward [Cincinnati, OH; Darkins, Jr., Toby George; Stumpf, James Anthony [Columbus, IN; Schroder, Mark S [Greenville, SC; Lipinski, John Joseph [Simpsonville, SC

2012-03-27

Methods and apparatus for a mounting assembly for a liner of a gas turbine engine combustor are provided. The combustor includes a combustor liner and a radially outer annular flow sleeve. The mounting assembly includes an inner ring surrounding a radially outer surface of the liner and including a plurality of axially extending fingers. The mounting assembly also includes a radially outer ring coupled to the inner ring through a plurality of spacers that extend radially from a radially outer surface of the inner ring to the outer ring.

Modeling of Slot Waveguide Sensors Based on Polymeric Materials

Science.gov (United States)

Bettotti, Paolo; Pitanti, Alessandro; Rigo, Eveline; De Leonardis, Francesco; Passaro, Vittorio M. N.; Pavesi, Lorenzo

2011-01-01

Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers) to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies. PMID:22164020

Modeling of Slot Waveguide Sensors Based on Polymeric Materials

Directory of Open Access Journals (Sweden)

Lorenzo Pavesi

2011-07-01

Full Text Available Slot waveguides are very promising for optical sensing applications because of their peculiar spatial mode profile. In this paper we have carried out a detailed analysis of mode confinement properties in slot waveguides realized in very low refractive index materials. We show that the sensitivity of a slot waveguide is not directly related to the refractive index contrast of high and low materials forming the waveguide. Thus, a careful design of the structures allows the realization of high sensitivity devices even in very low refractive index materials (e.g., polymers to be achieved. Advantages of low index dielectrics in terms of cost, functionalization and ease of fabrication are discussed while keeping both CMOS compatibility and integrable design schemes. Finally, applications of low index slot waveguides as substitute of bulky fiber capillary sensors or in ring resonator architectures are addressed. Theoretical results of this work are relevant to well established polymer technologies.

Investigation of slot discharge on a 239 MVA hydro generator stator winding

Energy Technology Data Exchange (ETDEWEB)

Li, S.; Hong, W. [BC Hydro and Power Authority, Vancouver, BC (Canada)

2009-07-01

This paper discussed a slot discharge investigation conducted on a 239 MVA generator stator winding. The generator in which the winding was located had experienced core split distortion, stator winding phase-to-phase failures, winding failures during Hipot testing, and high partial discharge (PD) activity. The results of on-line PD testing data were evaluated. The stator winding was subjected to visual inspections, bar dissections, and failure mechanism analyses. Eleven winding bars were removed from the stator slots in order to assess groundwall insulation conditions and identify the cause of the slot discharge activity. It was determined that the root cause of the slot discharge was a loose, non-uniform bar in the slot. The vibrating bar caused the semi-conductive coating to wear out and degraded the armour tape. Results of the study demonstrated the importance of on-line PD monitoring for detecting slot PD activity. 4 refs., 3 tabs., 11 figs.

Collaborative en-route and slot allocation algorithm based on fuzzy comprehensive evaluation

Science.gov (United States)

Yang, Shangwen; Guo, Baohua; Xiao, Xuefei; Gao, Haichao

2018-01-01

To allocate the en-routes and slots to the flights with collaborative decision making, a collaborative en-route and slot allocation algorithm based on fuzzy comprehensive evaluation was proposed. Evaluation indexes include flight delay costs, delay time and the number of turning points. Analytic hierarchy process is applied to determining index weights. Remark set for current two flights not yet obtained the en-route and slot in flight schedule is established. Then, fuzzy comprehensive evaluation is performed, and the en-route and slot for the current two flights are determined. Continue selecting the flight not yet obtained an en-route and a slot in flight schedule. Perform fuzzy comprehensive evaluation until all flights have obtained the en-routes and slots. MatlabR2007b was applied to numerical test based on the simulated data of a civil en-route. Test results show that, compared with the traditional strategy of first come first service, the algorithm gains better effect. The effectiveness of the algorithm was verified.

Composição química e aspecto superficial do slot de braquetes metálicos Elemental composition and superficial aspect of metallic brackets slot

Directory of Open Access Journals (Sweden)

Tatiana Féres Assad-Loss

2008-06-01

- Dentaurum; group 4 - stainless steel (Standard - TP Orthodontics; group 5 - stainless steel (Serie light - American Orthodontics; group 6 - stainless steel (Kirium Line - Abzil Lancer; group 7 - stainless steel (Monobloc - Morelli; group 8 - stainless steel (Standard - Morelli and group 9 - stainless steel (Monobloc Golden - Morelli. METHODS: Elemental composition was evaluated using the Spectroscopy of Dispersive Energy. The qualitative slot surface evaluation was assessed using a 500X scanning electron microscope. The microphotography was classified according to surface characteristics in 0-8 values. RESULTS: Elemental composition - group 1 = 100% titanium alloy; group 9 = 99,48% of titanium nitride coated. Group 3 = cobalt-chromium alloy; Group 8 = nickel free stainless steel alloy; other groups stainless steel alloy. Surface evaluation - Group 1 = value 2 (smoothest surface; Groups 2, 5 and 7 =value 3 (smooth surface; Groups 3, 8 and 9 showed value 6 (roughness surface; Group 4 = value 6,5 (the most roughness and irregular surface; and Group 6 has intermediate characteristics among the groups, with value 5. CONCLUSIONS: Metallic brackets were composed of different alloys and they were available with a small percentage or no nickel. The surface roughness was similar for both titanium and stainless steel, however the titanium nitride coated and cobalt-chromium showed an irregular and rough surface.

MM99.50 - Surface Topography Characterization Using an Atomic Force Microscope Mounted on a Coordinate Measuring Machine

DEFF Research Database (Denmark)

Chiffre, Leonardo De; Hansen, Hans Nørgaard; Kofod, Niels

1999-01-01

The paper describes the construction, testing and use of an integrated system for topographic characterization of fine surfaces on parts having relatively big dimensions. An atomic force microscope (AFM) was mounted on a manual three-coordinate measuring machine (CMM) achieving free positioning o...

Tilt signals at Mount Melbourne, Antarctica: evidence of a shallow volcanic source

Directory of Open Access Journals (Sweden)

Salvatore Gambino

2016-06-01

Full Text Available Mount Melbourne (74°21′ S, 164°43′ E is a quiescent volcano located in northern Victoria Land, Antarctica. Tilt signals have been recorded on Mount Melbourne since early 1989 by a permanent shallow borehole tiltmeter network comprising five stations. An overall picture of tilt, air and permafrost temperatures over 15 years of continuous recording data is reported. We focused our observations on long-term tilt trends that at the end of 1997 showed coherent changes at the three highest altitude stations, suggesting the presence of a ground deformation source whose effects are restricted to the summit area of Mount Melbourne. We inverted these data using a finite spherical body source, thereby obtaining a shallow deflation volume source located under the summit area. The ground deformation observed corroborates the hypothesis that the volcanic edifice of Mount Melbourne is active and should be monitored multidisciplinarily.

Bi2O3 nanoparticles encapsulated in surface mounted metal-organic framework thin films

Science.gov (United States)

Guo, Wei; Chen, Zhi; Yang, Chengwu; Neumann, Tobias; Kübel, Christian; Wenzel, Wolfgang; Welle, Alexander; Pfleging, Wilhelm; Shekhah, Osama; Wöll, Christof; Redel, Engelbert

2016-03-01

We describe a novel procedure to fabricate a recyclable hybrid-photocatalyst based on Bi2O3@HKUST-1 MOF porous thin films. Bi2O3 nanoparticles (NPs) were synthesized within HKUST-1 (or Cu3(BTC)2) surface-mounted metal-organic frame-works (SURMOFs) and characterized using X-ray diffraction (XRD), a quartz crystal microbalance (QCM) and transmission electron microscopy (TEM). The Bi2O3 semiconductor NPs (diameter 1-3 nm)/SURMOF heterostructures exhibit superior photo-efficiencies compared to NPs synthesized using conventional routes, as demonstrated via the photodegradation of the nuclear fast red (NFR) dye.We describe a novel procedure to fabricate a recyclable hybrid-photocatalyst based on Bi2O3@HKUST-1 MOF porous thin films. Bi2O3 nanoparticles (NPs) were synthesized within HKUST-1 (or Cu3(BTC)2) surface-mounted metal-organic frame-works (SURMOFs) and characterized using X-ray diffraction (XRD), a quartz crystal microbalance (QCM) and transmission electron microscopy (TEM). The Bi2O3 semiconductor NPs (diameter 1-3 nm)/SURMOF heterostructures exhibit superior photo-efficiencies compared to NPs synthesized using conventional routes, as demonstrated via the photodegradation of the nuclear fast red (NFR) dye. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr00532b

Optimization and Design for a Radial Flux Permanent Magnet Motor for Electric Vehicle

Directory of Open Access Journals (Sweden)

R. NEJI

2005-12-01

Full Text Available This paper deals with the design and the optimization of permanent magnet motors. Five trapezoidal and four sinusoidal wave-form motor configurations were investigated and analyzed. Firstly, an analytic sizing was led along with an electromagnetic modeling by finite element method. Secondly, a finer modeling with finite element was realized dynamically. The optimization of the traction motor cost under constraints by the genetic algorithms method has allowed choosing a motor with sinusoidal wave-form, five pole pairs and twelve slots. This motor belongs to the second configuration with sinusoidal wave-form.

Energy characteristics of the double slot in the narrow wall of a rectangular waveguide

OpenAIRE

Martynenko, S. A.

2005-01-01

Based on approximation of the half-wave field distribution in the slots, an expression is derived for internal mutual conductance of closely-spaced slots, which form a double inclined slot in the narrow wall of a rectangular waveguide. The narrow wall has cut-outs reaching the broad wall. With the use of the method of induced magnetomotive forces, a mathematical model is devised for calculating the energy characteristics of the double slot. The impact of angle of inclination of the slots, dim...

Non-similar solutions for unsteady flow over a yawed cylinder with non-uniform mass transfer through a slot

Directory of Open Access Journals (Sweden)

G. Revathi

2014-12-01

Full Text Available Non-similar solutions are found numerically to a system of coupled non-linear partial differential equations indicating, unsteady laminar water boundary layer flow over yawed cylinder using implicit finite difference scheme along with Quasi-linearization technique. The fluid properties such as viscosity and Prandtl number are considered as an inverse function of temperature. Unsteadiness is caused by upstream velocity in and directions and non-uniform mass transfer (suction/injection which is applied through slot on the surface of the geometry. The effect of yaw angle, variable fluid properties and non-uniform mass transfer on skin friction and heat transfer coefficients is analyzed. It is found that non-uniform slot suction and downstream movement of the slot cause the point of vanishing skin friction moves downstream, but non-uniform slot injection produces the opposite result of that corresponding to the suction case. When the yaw angle increases, both the skin friction coefficient in the – direction and the heat transfer coefficient decrease but the skin friction coefficient in the – direction increases for all times. The effect of the yaw angle is very little on the point of vanishing skin friction.

Broadcast Coded Slotted ALOHA

DEFF Research Database (Denmark)

Ivanov, Mikhail; Brännström, Frederik; Graell i Amat, Alexandre

2016-01-01

We propose an uncoordinated medium access control (MAC) protocol, called all-to-all broadcast coded slotted ALOHA (B-CSA) for reliable all-to-all broadcast with strict latency constraints. In B-CSA, each user acts as both transmitter and receiver in a half-duplex mode. The half-duplex mode gives ...

Results of pressurized-slot measurements in the G-Tunnel underground facility

International Nuclear Information System (INIS)

Zimmerman, R.M.; Mann, K.L.; Dodds, D.J.

1989-01-01

A rock-mechanics field-testing program is underway at Sandia National Laboratories (SNL) as part of the YMP. SNL has the responsibility for assessing the repository design and performance as well as characterizing the geomechanical behavior of the rock. SNL has conducted field experiments in G-Tunnel in Rainier Mesa at the NTS, where tuffs similar to those at Yucca Mountain, the potential repository site, are found. Later experiments are planned as part of the YMP Exploratory Shaft investigations at Yucca Mountain. Major geomechanical factors in repository developments are determinations of the stress state and the deformability of the rock mass (described by the modulus of deformation). One feature of SNL's rock-mechanics program was the development of a testing program for cutting thin slots in a jointed welded tuff and utilizing flatjacks for pressurizing these thin-slots on a relatively, large scale. Objectives in the pressurized-slot testing in G-Tunnel have been to apply and possibly improve methods for (1) utilizing the flatjack cancellation (FC) method for measuring stresses normal to the slot and (2) measuring the modulus of deformation of the jointed rock surrounding the slot. This paper discusses the results of field measurements in and around a single slot and evaluates potential applications and limitations. 10 refs., 1 fig., 4 tabs

Slot-dimer babinet metamaterials as polarization shapers for terahertz waves

DEFF Research Database (Denmark)

Zhukovsky, Sergei; Chigrin, D. N.; Lavrinenko, Andrei

2013-01-01

We theoretically study optical properties of free-standing metallic membranes patterned with an array of two-slot elements (dimers) comprising two rectangular slots of different dimensions and orientation. It is shown that these structures feature extraordinary optical transmission with strong...

Crossed-Slot Cavity-Backed Antenna with Improved Hemispherical Coverage

DEFF Research Database (Denmark)

Kim, Oleksiy S.; Breinbjerg, Olav; Østergaard, Allan

2005-01-01

The paper presents the results of the investigation of the crossed-slot cavity-backed antenna with the complementary crossed electric dipoles added to compensate the circularly polarized (CP) radiation pattern degradation near the horizon. Dependences of the radiation characteristics...... of the modified crossed-slot cavity-backed antenna on the length, width and height of the crossed electric dipoles are shown. Effects of a finite size ground plane are taken into account due to a full wave electromagnetic analysis software utilized in the parametrical investigations. Simulated and measured...... results for a selected antenna configuration prove that the properly adjusted crossed electric dipoles are able to improve the coverage and CP polarization characteristics of the crossed-slot cavity-backed antenna....

Slot-type pickup/kicker for AA stochastic cooling

CERN Multimedia

CERN PhotoLab

1979-01-01

A "slotted transmission line" was used for both pickups and kickers of the cooling systems of the AA. They served for the cooling of the high-density antiproton stack, in momentum and both transverse planes. In the beginning in a single band, 1-2 GHz, later in 2 bands, 2-4 and 4-8 GHz. Here we see the slotted electrodes partly pulled out of the outer casing. See also 7906189, 7906581X, 7896193.

Mounting apparatus for a nozzle guide vane assembly

Science.gov (United States)

Boyd, Gary L.; Shaffer, James E.

1995-01-01

The present invention provides a ceramic nozzle guide assembly with an apparatus for mounting it to a metal nozzle case that includes an intermediate ceramic mounting ring. The mounting ring includes a plurality of projections that are received within a plurality of receptacles formed in the nozzle case. The projections of the mounting ring are secured within the receptacles by a ceramic retainer that allows contact between the two components only along arcuate surfaces thus eliminating sliding contact between the components.

Slotted cage resonator for high-field magnetic resonance imaging of rodents

Energy Technology Data Exchange (ETDEWEB)

Marrufo, O; Vasquez, F; Solis, S E; Rodriguez, A O, E-mail: arog@xanum.uam.mx [Departamento de Ingenieria Electrica, Universidad Autonoma Metropolitana Iztapalapa, Mexico, DF 09340 (Mexico)

2011-04-20

A variation of the high-frequency cavity resonator coil was experimentally developed according to the theoretical frame proposed by Mansfield in 1990. Circular slots were used instead of cavities to form the coil endplates and it was called the slotted cage resonator coil. The theoretical principles were validated via a coil equivalent circuit and also experimentally with a coil prototype. The radio frequency magnetic field, B1, produced by several coil configurations was numerically simulated using the finite-element approach to investigate their performances. A transceiver coil, 8 cm long and 7.6 cm in diameter, and composed of 4 circular slots with a 15 mm diameter on both endplates, was built to operate at 300 MHz and quadrature driven. Experimental results obtained with the slotted cage resonator coil were presented and showed very good agreement with the theoretical expectations for the resonant frequency as a function of the coil dimensions and slots. A standard birdcage coil was also built for performance comparison purposes. Phantom images were then acquired to compute the signal-to-noise ratio of both coils showing an important improvement of the slotted cage coil over the birdcage coil. The whole-body images of the mouse were also obtained showing high-quality images. Volume resonator coils can be reliably built following the physical principles of the cavity resonator design for high-field magnetic resonance imaging applications of rodents.

Evaluation of two styles of slotted, flat-head screws

International Nuclear Information System (INIS)

Reeves, C.A. Jr.; Johnson, W.B.

1979-01-01

A series of torque tests were performed to evaluate the relative merits of two different flat-head screws fabricated from a uranium--6% niobium alloy. The screws tested were machined with both normal, straight-through slots in the head and with slots having radiused bottoms. Test results indicate that both designs easily surpass the required 20-inch-pound-proof torque

Development of high power models of four-slot Annular Coupled Structure

International Nuclear Information System (INIS)

Kageyama, T.; Morozumi, Y.; Yoshino, K.; Yamazaki, Y.

1994-01-01

A π/2-mode standing-wave linac (f=1.296 GHz) of an Annular Coupled Structure (ACS) has been developed for the 1-GeV proton linac of the Japanese Hadron Project (JHP). This ACS has four coupling slots between accelerating and coupling cells in order to suppress higher order mode mixing with the π/2 coupling mode. High-β(β=v/c=0.78) and low-β(0.52) prototypes were constructed and tested up to each design RF power. Concerning the effect of the coupling slots on the fields of a coupled-cavity linac, it was found that the slot configuration of the side-coupled structure (SCS) tilts the accelerating field. On the other hand, the four-slot configuration of the ACS gives an almost axially symmetric accelerating field to the beam. (author)

High slot utilization systems for electric machines

Science.gov (United States)

Hsu, John S

2009-06-23

Two new High Slot Utilization (HSU) Systems for electric machines enable the use of form wound coils that have the highest fill factor and the best use of magnetic materials. The epoxy/resin/curing treatment ensures the mechanical strength of the assembly of teeth, core, and coils. In addition, the first HSU system allows the coil layers to be moved inside the slots for the assembly purpose. The second system uses the slided-in teeth instead of the plugged-in teeth. The power density of the electric machine that uses either system can reach its highest limit.

Detector Mount Design for IGRINS

Directory of Open Access Journals (Sweden)

Jae Sok Oh

2014-06-01

Full Text Available The Immersion Grating Infrared Spectrometer (IGRINS is a near-infrared wide-band high-resolution spectrograph jointly developed by the Korea Astronomy and Space Science Institute and the University of Texas at Austin. IGRINS employs three HAWAII-2RG Focal Plane Array (H2RG FPA detectors. We present the design and fabrication of the detector mount for the H2RG detector. The detector mount consists of a detector housing, an ASIC housing, a Field Flattener Lens (FFL mount, and a support base frame. The detector and the ASIC housing should be kept at 65 K and the support base frame at 130 K. Therefore they are thermally isolated by the support made of GFRP material. The detector mount is designed so that it has features of fine adjusting the position of the detector surface in the optical axis and of fine adjusting yaw and pitch angles in order to utilize as an optical system alignment compensator. We optimized the structural stability and thermal characteristics of the mount design using computer-aided 3D modeling and finite element analysis. Based on the structural and thermal analysis, the designed detector mount meets an optical stability tolerance and system thermal requirements. Actual detector mount fabricated based on the design has been installed into the IGRINS cryostat and successfully passed a vacuum test and a cold test.

Improvement The Transmission Efficiency For Wireless Packet Communication Systems Using Automatic Control for power And Time Slot Width Of Slotted Non persistent ISMA Protocol

Directory of Open Access Journals (Sweden)

Saad M. Hardan

2013-05-01

Full Text Available In packed communication systems which use a protocol, the protocol should perform the allocation of channels such that the transmission channel is used efficiently. Efficiency is usually measured in terms of channel throughput and the average transmission  delay. The Slotted Nonpersistent ISMA protocol is one of random access protocols used in packed communication systems. In this research a Slotted Nonpersistent ISMA protocol Model with automatic control for power and time slot is proposed. the suggested algorithm enable the base station(access point to control  the protocol time slot length and  transmission power in a dynamic way to control the normalized propagation delay d and to maintain all the uplink signals in the limit of captured power threshold (capture ratio in order to control the  throughput and the average transmission delay of the communication system by an automatic method. the computer simulation results  confirm the activity of the  proposed algorithm for increasing the  throughput and decreasing the average transmission delay by an accepted ratios.

Bead beavior in a non-continues slot die coating regime

NARCIS (Netherlands)

Langen, A.; Senes, A.; Vries, I. de; Groen, P.

2015-01-01

Sheet-to-sheet slot die coating is a crucial intermediate technique to bring organic and large area electronics (e.g. OLED and Flexible OPV) towards mass roll-to-roll productions. The coating on substrate has to be uniform within nanometers. Additional settings are added to the slot die coater for a

Development of an economical and ecological optimized multi slot fish bypass

International Nuclear Information System (INIS)

Tauber, M.; Mader, H.

2009-01-01

The European Union's Water Framework Directive (WFD), which came into force in 2000, represents a new framework governing water policies. The ecological objectives of the directive are sometimes in conflict with the historical use of waterbodies for hydropower generation. This paper discussed the mitigation of negative economical effects caused by outfitting hydropower plants with fish migration facilities claimed by the WFD. In particular, it reviewed the new modified version of the Vertical Slot Fishpass which reduces water discharge while maintaining or even enhancing the biological migration of aquatic species. Reducing the flow rate in the fish bypass results in more available water for hydropower generation, which is economically advantageous for operators. The available water resource is simply used more efficiently. The bypass was modified by adding additional slot baffles and guide walls in order to induce intended losses at roughness obstacles and to obtain isolated roughness current in the multi slot area. A Froude similarity model was used to obtain the results of the first phase of this project. Different arrangements of the slot baffles and locations were measured. The results of all trials revealed that the newly developed multi slot variants have clear advantages over conventional vertical slot fish passages. Discharge was reduced by up to 34 per cent while still maintaining the same water levels in the pools. As such, the general flow velocities were also reduced by about 10 per cent, thereby achieving the primary objective of the project. 7 refs., 18 figs

The metallurgical approach on the solder voids behaviour in surface mount devices

International Nuclear Information System (INIS)

Mohabattul Zaman Bukhari

1996-01-01

Solder voids are believed to cause poor heat dissiption in the Surface Mount devices and reduce the reliability of the devices at higher operating services. There are a lot of factors involved in creating voids such as gas/flux entrapment, wettability, outgasseous, air bubbles in the solder paste, inconsistency of solder coverage and improper metal scheme selection. This study was done to observe the behaviour of the solder voids in term of flux entrapmentt and wettability. It is believed that flux entrapment and wettability are verify this hypothesis. Two types of metal scheme were chosen which are Nickel (Ni) plated and Tin (Sn) plated heatsink. X-ray techniques such as Radiographic Inspection Analysis and EDAX were used to detect the minute solder voids. The solder voids observed on the heatsinks and Copper shims after the reflow process are believed to be a non contact voids that resulted from some portion of the surface not wetting properly

A model of gas flow with friction in a slotted seal

Directory of Open Access Journals (Sweden)

Joachimiak Damian

2016-09-01

Full Text Available The paper discusses thermodynamic phenomena accompanying the flow of gas in a slotted seal. The analysis of the gas flow has been described based on an irreversible adiabatic transformation. A model based on the equation of total enthalpy balance has been proposed. The iterative process of the model aims at obtaining such a gas temperature distribution that will fulfill the continuity equation. The model allows for dissipation of the kinetic energy into friction heat by making use of the Blasius equation to determine the friction coefficient. Within the works, experimental research has been performed of the gas flow in a slotted seal of slot height 2 mm. Based on the experimental data, the equation of local friction coefficient was modified with a correction parameter. This parameter was described with the function of pressure ratio to obtain a mass flow of the value from the experiment. The reason for taking up of this problem is the absence of high accuracy models for calculating the gas flow in slotted seals. The proposed model allows an accurate determination of the mass flow in a slotted seal based on the geometry and gas initial and final parameters.

Modeling fiber motion in a pulp pressure screen: the effect of slot shape

International Nuclear Information System (INIS)

Dong, S.; Salcudean, M.; Gartshore, I.

2003-01-01

A pressure screen is a piece of equipment in the pulp and paper industry used either to remove contaminants from the pulp suspension or to separate fibers having different properties. Contaminants such as fiber bundles, bark and plastic specks are introduced when fibers are separated from the wood by mechanical or chemical pulping processes. Contaminants significantly affect the strength and smoothness of the paper and must be removed before the final paper is produced. The screen plate is a critical part of the pressure screen and its design is the key to screen performance. This paper uses a new and comprehensive CFD simulation tool to examine the flow and fiber behavior in a single slot screen having any reasonable slot shape. -This simulation tool includes three coupled models: first, the flow model solves the Reynolds Averaged Navier-Stokes (RANS) equation using the standard k - ε turbulence model to predict the flow field in the equipment. Second, a three-dimensional flexible fiber model is used to track the fiber trajectory in the screen. Third, a very general wall model is used to deal with the case when a fiber touches the equipment wall. The simulated results show that the slot shape has a critical influence on fiber behavior and screen performance. Three general slot shapes were investigated: the smooth slot, the step-step contour slot and slope-slope contour slot. Of these the slope-slope contour slot provides the best passage for the fibers with a length of 1mm and 3mm. (author)

Accurate torque-sensorless control approach for interior permanent-magnet synchronous machine based on cascaded sliding mode observer

Directory of Open Access Journals (Sweden)

Kai-Hui Zhao

2017-06-01

Full Text Available To improve the accuracy of torque control for vector control of interior permanent-magnet synchronous machine (IPMSM, this study proposes a torque-sensorless control method based on cascaded sliding mode observer (SMO. First, the active flux model is discussed, which converts the model of IPMSM into the equivalent model of surface-mounted permanent-magnet synchronous machine. Second, to reduce chattering caused by system parameters variations and external disturbances, the cascaded observer is designed, which is composed of a variable gain adaptive SMO and an active flux SMO. The variable gain adaptive SMO is designed to estimate the speed, rotor position and stator resistance in the d–q reference frame. The active flux SMO is designed to estimate the active flux and torque in the α–β reference frame. Global asymptotic stability of the observers is guaranteed by the Lyapunov stability analysis. Finally, simulations and experiments are carried out to verify the effectiveness of the proposed control scheme.

Study on wake structure characteristics of a slotted micro-ramp with large-eddy simulation

Energy Technology Data Exchange (ETDEWEB)

Dong, Xiangrui; Chen, Yaohui; Dong, Gang; Liu, Yixin, E-mail: cyh873@163.com [National Key Laboratory of Transient Physics, Nanjing University of Science and Technology, Nanjing, 210094 (China)

2017-06-15

In this paper, a novel slotted ramp-type micro vortex generator (slotted micro-ramp) for flow separation control is simulated in the supersonic flow of Ma = 1.5, based on large eddy simulation combined with the finite volume method. The wake structure characteristics and control mechanisms of both slotted and standard micro-ramps are presented and discussed. The results show that the wake of standard micro-ramp includes a primary counter-rotating streamwise vortex pair, a train of vortex rings, and secondary vortices. The slotted micro-ramp has more complicated wake structures, which contain a confluent counter-rotating streamwise vortex pair and additional streamwise vortices, with the same rotation generated by slot and the vortex rings enveloping the vortex pair. The additional vortices generated by the slot of the micro-ramp can mix with the primary counter-rotating vortex pair, extend the life time, and strengthen the vortex intensity of primary vortex pair. Moreover, the slot can effectively alleviate, or even eliminate the backflow and decrease the profile drag induced by the standard micro-ramp, therefore improving the efficiency of separation control. (paper)

Slot technique - an alternative method of scatter reduction in radiography

International Nuclear Information System (INIS)

Panzer, W.; Widenmann, L.

1983-01-01

The most common method of scatter reduction in radiography is the use of an antiscatter grid. Its disadvantage is the absorption of a certain percentage of primary radiation in the lead strips of the grid and the fact that due to the limited thickness of the lead strips their scatter absorption is also limited. A possibility for avoiding this disadvantage is offered by the so-called slot technique, ie, the successive exposure of the subject with a narrow fan beam provided by slots in rather thick lead plates. The results of a comparison between grid and slot technique regarding dose to the patient, scatter reduction, image quality and the effect of automatic exposure control are reported. (author)

Classification of surface types using SIR-C/X-SAR, Mount Everest Area, Tibet

Science.gov (United States)

Albright, Thomas P.; Painter, Thomas H.; Roberts, Dar A.; Shi, Jiancheng; Dozier, Jeff; Fielding, Eric

1998-01-01

Imaging radar is a promising tool for mapping snow and ice cover in alpine regions. It combines a high-resolution, day or night, all-weather imaging capability with sensitivity to hydrologic and climatic snow and ice parameters. We use the spaceborne imaging radar-C/X-band synthetic aperture radar (SIR-C/X-SAR) to map snow and glacial ice on the rugged north slope of Mount Everest. From interferometrically derived digital elevation data, we compute the terrain calibration factor and cosine of the local illumination angle. We then process and terrain-correct radar data sets acquired on April 16, 1994. In addition to the spectral data, we include surface slope to improve discrimination among several surface types. These data sets are then used in a decision tree to generate an image classification. This method is successful in identifying and mapping scree/talus, dry snow, dry snow-covered glacier, wet snow-covered glacier, and rock-covered glacier, as corroborated by comparison with existing surface cover maps and other ancillary information. Application of the classification scheme to data acquired on October 7 of the same year yields accurate results for most surface types but underreports the extent of dry snow cover.

Tri-Band CPW-Fed Stub-Loaded Slot Antenna Design for WLAN/WiMAX Applications

Science.gov (United States)

Li, Jianxing; Guo, Jianying; He, Bin; Zhang, Anxue; Liu, Qing Huo

2016-11-01

A novel uniplanar CPW-fed tri-band stub-loaded slot antenna is proposed for wireless local area network (WLAN) and worldwide interoperability for microwave access (WiMAX) applications. Dual resonant modes were effectively excited in the upper band by using two identical pairs of slot stubs and parasitic slots symmetrically along the arms of a traditional CPW-fed slot dipole, achieving a much wider bandwidth. The middle band was realized by the fundamental mode of the slot dipole. To obtain the lower band, two identical inverted-L-shaped open-ended slots were symmetrically etched in the ground plane. A prototype was fabricated and measured, showing that tri-band operation with 10-dB return loss bandwidths of 150 MHz from 2.375 to 2.525 GHz, 725 MHz from 3.075 to 3.8 GHz, and 1.9 GHz from 5.0 to 6.9 GHz has been achieved. Details of the antenna design as well as the measured and simulated results are presented and discussed.

AMELIA CESTOL Test: Acoustic Characteristics of Circulation Control Wing with Leading- and Trailing-Edge Slot Blowing

Science.gov (United States)

Horne, William C.; Burnside, Nathan J.

2013-01-01

The AMELIA Cruise-Efficient Short Take-off and Landing (CESTOL) configuration concept was developed to meet future requirements of reduced field length, noise, and fuel burn by researchers at Cal Poly, San Luis Obispo and Georgia Tech Research Institute under sponsorship by the NASA Fundamental Aeronautics Program (FAP), Subsonic Fixed Wing Project. The novel configuration includes leading- and trailing-edge circulation control wing (CCW), over-wing podded turbine propulsion simulation (TPS). Extensive aerodynamic measurements of forces, surfaces pressures, and wing surface skin friction measurements were recently measured over a wide range of test conditions in the Arnold Engineering Development Center(AEDC) National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Ft Wind Tunnel. Acoustic measurements of the model were also acquired for each configuration with 7 fixed microphones on a line under the left wing, and with a 48-element, 40-inch diameter phased microphone array under the right wing. This presentation will discuss acoustic characteristics of the CCW system for a variety of tunnel speeds (0 to 120 kts), model configurations (leading edge(LE) and/or trailing-edge(TE) slot blowing, and orientations (incidence and yaw) based on acoustic measurements acquired concurrently with the aerodynamic measurements. The flow coefficient, Cmu= mVSLOT/qSW varied from 0 to 0.88 at 40 kts, and from 0 to 0.15 at 120 kts. Here m is the slot mass flow rate, VSLOT is the slot exit velocity, q is dynamic pressure, and SW is wing surface area. Directivities at selected 1/3 octave bands will be compared with comparable measurements of a 2-D wing at GTRI, as will as microphone array near-field measurements of the right wing at maximum flow rate. The presentation will include discussion of acoustic sensor calibrations as well as characterization of the wind tunnel background noise environment.

Magnetic Field Equivalent Current Analysis-Based Radial Force Control for Bearingless Permanent Magnet Synchronous Motors

Directory of Open Access Journals (Sweden)

Huangqiu Zhu

2015-05-01

Full Text Available Bearingless permanent magnet synchronous motors (BPMSMs, with all advantages of permanent magnet motors (PMSMs and magnetic bearings, have become an important research direction in the bearingless motor field. To realize a stable suspension for the BPMSM, accurate decoupling control between the electromagnetic torque and radial suspension force is indispensable. In this paper, a concise and reliable analysis method based on a magnetic field equivalent current is presented. By this analysis method, the operation principle is analyzed theoretically, and the necessary conditions to produce a stable radial suspension force are confirmed. In addition, mathematical models of the torque and radial suspension force are established which is verified by the finite element analysis (FEA software ANSYS. Finally, an experimental prototype of a 2-4 poles surface-mounted BPMSM is tested with the customized control strategy. The simulation and experimental results have shown that the motor has good rotation and suspension performance, and validated the accuracy of the proposed analysis method and the feasibility of the control strategy.

Investigation of a Novel Turbulence Model and Using Leading-Edge Slots for Improving the Aerodynamic Performance of Airfoils and Wind Turbines

Science.gov (United States)

Beyhaghi, Saman

Because of the problems associated with increase of greenhouse gases, as well as the limited supplies of fossil fuels, the transition to alternate, clean, renewable sources of energy is inevitable. Renewable sources of energy can be used to decrease our need for fossil fuels, thus reducing impact to humans, other species and their habitats. The wind is one of the cleanest forms of energy, and it can be an excellent candidate for producing electrical energy in a more sustainable manner. Vertical- and Horizontal-Axis Wind Turbines (VAWT and HAWT) are two common devices used for harvesting electrical energy from the wind. Due to the development of a thin boundary layer over the ground surface, the modern commercial wind turbines have to be relatively large to be cost-effective. Because of the high manufacturing and transportation costs of the wind turbine components, it is necessary to evaluate the design and predict the performance of the turbine prior to shipping it to the site, where it is to be installed. Computational Fluid Dynamics (CFD) has proven to be a simple, cheap and yet relatively accurate tool for prediction of wind turbine performance, where the suitability of different designs can be evaluated at a low cost. High accuracy simulation methods such as Large Eddy Simulation (LES) and Detached Eddy Simulation (DES) are developed and utilized in the past decades. Despite their superior importance in large fluid domains, they fail to make very accurate predictions near the solid surfaces. Therefore, in the present effort, the possibility of improving near-wall predictions of CFD simulations in the near-wall region by using a modified turbulence model is also thoroughly investigated. Algebraic Stress Model (ASM) is employed in conjunction with Detached Eddy Simulation (DES) to improve Reynolds stresses components, and consequently predictions of the near-wall velocities and surface pressure distributions. The proposed model shows a slightly better performance

FEM Analysis of Brushless DC Servomotor with Fractional Number of Slots per Pole

Directory of Open Access Journals (Sweden)

BALUTA, G.

2014-02-01

Full Text Available The authors present in this paper the analysis with Finite Element Method (FEM of the magnetic circuit for a Brushless DC servomotor with fractional number of slots/pole (9 slots and 10 poles. For this purpose, FEMM 4.2 software package was used for the analysis. To obtain the waveforms of Back-ElectroMotive Forces (BEMFs, electromagnetic and cogging torque for servomotor a program in LUA scripting language (integrated into interactive shell of FEMM4.2 has been created. A comparation with a structure with integer number of slots/pole (18 slots and 6 poles was also realized. The analysis results prove that the structure chosen is an optimal solution: sinusoidal waveforms of BEMFs, improved electromagnetic torque and reduced cogging torque. Therefore, the operating characteristics of the servomotor with 9/10 slots/poles manufactured by Sistem Euroteh Company and included in an integrated electrical drives system are presented in this paper.

Improved Eddy-current Field Loss Model and Scaling Index for Magnets of Permanent Magnet Synchronous Motors

Directory of Open Access Journals (Sweden)

Zhang Lei

2015-01-01

Full Text Available The paper gives detailed systematic researches on the mechanism and key factors of eddy-current losses in rotor magnets of high power-density permanent magnet synchronous motors(PMSMs. Firstly, this paper establishes quantitative mathematic model of eddy-current losses for surface-mounted PMSM based on eddy current field model and Maxwell equations. Then, a scaling index is put forward to weigh the key factors relevant to the eddy-current losses in magnets. At the same time, the principles of eddy-current losses in prototype PMSM are analyzed by the finite element analysis (FEA software. The contents researched in the paper have practical reference values for design and reliability analysis of PMSMs.

Root surface area measurement of permanent dentition in Indian population – CBCT analysis

Directory of Open Access Journals (Sweden)

Kanika Lakhani

2017-01-01

Full Text Available The area of the root surface of human teeth has been investigated extensively in the dental literature. All previous attempts mainly rely on the use of physical methods to calculate surface area on extracted teeth or use virtual 3D Models for the same. The aim is to develop an algorithm using MATLAB software that estimates the dimensions of 3-D image produced with the help of CBCT so that the same can be utilized to calculate the root surface area of teeth among Indian population. Present research utilizes CBCT images of samples of extracted teeth mounted on a customized jpg. A descriptive chart for statistical analysis has been prepared to obtain average root surface area of each tooth type. The currently developed algorithm has been successfully applied to the CBCT images of complete sample of teeth to obtain their root surface area. The algorithm developed to calculate root surface area of the teeth holds wide spread application in the field of dentistry pursuing its high expediency in even various specializations of dentistry including orthodontics, prosthodontics, periodontology and implantalogy. It is concluded that it has now become a reality to accurately determine the surface area of the root of human teeth without extracting them using the CBCT radiographs of the patients.

A Novel Dual-Band Circularly Polarized Rectangular Slot Antenna

Directory of Open Access Journals (Sweden)

Biao Li

2016-01-01

Full Text Available A coplanar waveguide fed dual-band circularly polarized rectangular slot antenna is presented. The proposed antenna consists of a rectangular metal frame acting as a ground and an S-shaped monopole as a radiator. The spatial distribution of the surface current density is employed to demonstrate that the circular polarization is generated by the S-shaped monopole which controls the path of the surface currents. An antenna prototype, having overall dimension 37 × 37 × 1 mm3, has been fabricated on FR4 substrate with dielectric constant 4.4. The proposed antenna achieves 10 dB return loss bandwidths and 3 dB axial ratio (AR in the frequency bands 2.39–2.81 GHz and 5.42–5.92 GHz, respectively. Both these characteristics are suitable for WLAN and WiMAX applications.

Hydraulic performance of a low specific speed centrifugal pump with Spanwise-Slotted Blades

International Nuclear Information System (INIS)

Ye, D X; Li, H; Wang, Y

2013-01-01

The hydraulic efficiency of a low specific speed centrifugal pump is low because of the long and narrow meridian flow passage, and the severe disk friction. Spanwise slotted blade flow control technology has been applied to the low specific speed centrifugal pump. This paper concluded that spanwise slotted blades can improve the pump performance in both experiments and simulations. In order to study the influence to the impeller and volute by spanwise slotted blade, impeller efficiency and volute efficiency were defined. The minimum volute efficiency and the maximum pump efficiency appear at the same time in the design flow condition in the unsteady simulation. The mechanism of spanwise slotted blade flow control technology should be researched furthermore

Electrodeposition of WO3 nanoparticles into surface mounted metal-organic framework HKUST-1 thin films

Science.gov (United States)

Yoo, Hyeonseok; Welle, Alexander; Guo, Wei; Choi, Jinsub; Redel, Engelbert

2017-03-01

We describe a novel procedure to fabricate WO3@surface-mounted metal-organic framework (SURMOF) hybrid materials by electrodeposition of WO3 nanoparticles into HKUST-1, also termed Cu3(BTC)2 SURMOFs. These materials have been characterized using x-ray diffraction, time-of-flight secondary ion mass spectrometry, scanning electron microscopy, x-ray photoelectron spectroscopy as well as linear sweep voltammetry. The WO3 semiconductor/SURMOF heterostructures were further tested as hybrid electrodes in their performance for hydrogen evolution reaction from water.

Biointrusion test plan for the Permanent Isolation Surface Barrier Prototype

International Nuclear Information System (INIS)

Link, S.O.; Cadwell, L.L.; Brandt, C.A.; Downs, J.L.; Rossi, R.E.; Gee, G.W.

1994-04-01

This document provides a testing and monitoring plan for the biological component of the prototype barrier slated for construction at the Hanford Site. The prototype barrier is an aboveground structure engineered to demonstrate the basic features of an earthen cover system. It is designed to permanently isolate waste from the biosphere. The features of the barrier include multiple layers of soil and rock materials and a low-permeability asphalt sublayer. The surface of the barrier consists of silt loam soil, covered with plants. The barrier sides are reinforced with rock or coarse earthen-fill to protect against wind and water erosion. The sublayers inhibit plant and animal intrusion and percolation of water. A series of tests will be conducted on the prototype barrier over the next several years to evaluate barrier performance under extreme climatic conditions. Plants and animals will play a significant role in the hydrologic and water and wind erosion characteristics of the prototype barrier. Studies on the biological component of the prototype barrier will include work on the initial revegetation of the surface, continued monitoring of the developing plant community, rooting depth and dispersion in the context of biointrusion potential, the role of plants in the hydrology of the surface and toe regions of the barrier, the role of plants in stabilizing the surface against water and wind erosion, and the role of burrowing animals in the hydrology and water and wind erosion of the barrier

Realistic Free-Spins Features Increase Preference for Slot Machines.

Science.gov (United States)

Taylor, Lorance F; Macaskill, Anne C; Hunt, Maree J

2017-06-01

Despite increasing research into how the structural characteristics of slot machines influence gambling behaviour there have been no experimental investigations into the effect of free-spins bonus features-a structural characteristic that is commonly central to the design of slot machines. This series of three experiments investigated the free-spins feature using slot machine simulations to determine whether participants allocate more wagers to a machine with free spins, and, which components of free-spins features drive this preference. In each experiment, participants were exposed to two computer-simulated slot machines-one with a free-spins feature or similar bonus feature and one without. Participants then completed a testing phase where they could freely switch between the two machines. In Experiment 1, participants did not prefer the machine with a simple free-spins feature. In Experiment 2 the free-spins feature incorporated additional elements such as sounds, animations, and an increased win frequency; participants preferred to gamble on this machine. The Experiment 3 "bonus feature" machine resembled the free spins machine in Experiment 2 except spins were not free; participants showed a clear preference for this machine also. These findings indicate that (1) free-spins features have a major influence over machine choice and (2) the "freeness" of the free-spins bonus features is not an important driver of preference, contrary to self-report and interview research with gamblers.

14 CFR 93.226 - Allocation of slots in low-demand periods.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Allocation of slots in low-demand periods. 93.226 Section 93.226 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... low-demand periods. (a) If there are available slots in the following time periods and there are no...

Elevated CPW-Fed Slotted Microstrip Antenna for Ultra-Wideband Application

Directory of Open Access Journals (Sweden)

Chandan Kumar Ghosh

2012-01-01

Full Text Available Elevated-coplanar-waveguide- (ECPW- fed microstrip antenna with inverted “G” slots in the back conductor is presented. It is modeled and analyzed for the application of multiple frequency bands. The changes in radiation and the transmission characteristics are investigated by the introduction of the slots in two different positions at the ground plane (back conductor. The proposed antenna without slots exhibits a stop band from 2.55 GHz to 4.25 GHz while introducing two slots on the back conductor, two adjacent poles appear at central frequencies of 3.0 GHz and 3.9 GHz, respectively, and the antenna shows the ultra-wideband (UWB characteristics. The first pole appears at the central frequency of 3.0 GHz and covers the band width of 950 MHz, and the second pole exists at a central frequency of 3.90 GHz covering a bandwidth of 750 MHz. Experimental result shows that impedance bandwidth of 129% (S11<-10 dB is well achieved when the antenna is excited with both slots. Compared to most of the previously reported ECPW structures, the impedance bandwidth of this antenna is increased and also the size of the antenna becomes smaller and more suitable for many wireless applications like PCS (1850–1990 MHz, WLAN (2.4–2.484 GHz, WiMAX (2.5–2.69 GHz and 5.15–5.85 GHz, and also X-band communication.

A water inner circulation device for a reactor vessel

International Nuclear Information System (INIS)

Eriksson, O.

1976-01-01

A water inner circulation device for a reactor vessel comprising a pump mounted in the reactor vessel and driven by a water-cooled electric motor mounted in a housing outside the reactor vessel, the shaft of the pump passing through the reactor-vessel bottom and being coupled to the motor shaft in a member mechanically connected to the bottom of the reactor vessel in the vicinity of the motor housing, the pump shaft being surrounded by a resilient sealing ring, the reactor vessel communicating with the cooling channels of the pump, when the latter is operating, via a slot surrounding the pump hollow cylindrical shaft, characterized in that the slot inner end is used for/forming a circular space surrounding the pump shaft and surrounded by the motorhousing, in which is coaxially mounted a separating cylindral wall, the upper edge of which is tightly applied against the inner wall of the motor-housing to which it is fastened vertically, the inner surface of said wall being turned towards the outer surface of a circular packing-box, the outer surface of said separating wall constituting a separating radical inner surface for a circular chamber through which flow the motor cooling water. (author)

Numerical study on non-locally reacting behavior of nacelle liners incorporating drainage slots

Science.gov (United States)

Chen, Chao; Li, Xiaodong; Thiele, Frank

2018-06-01

For acoustic liners used in current commercial nacelles, in order to prevent any liquid accumulating in the resonators, drainage slots are incorporated on the partition walls between closely packed cavities. Recently, an experimental study conducted by Busse-Gerstengarbe et al. shown that the cell interaction introduced by drainage slots causes an additional dissipation peak which increases with the size of the slot. However, the variation of damping process due to drainage slots is still not fully understood. Therefore, a numerical study based on computational aeroacoustic methods is carried out to investigate the mechanism of the changed attenuation characteristics due to drainage slots in presence of grazing incident sound waves with low or high intensities. Different slot configurations are designed based on the generic non-locally reacting liner model adopted in the experimental investigation. Both 2-D and 3-D numerical simulations of only slit resonators are carried out. Numerical results indicate that the extra peak is a result of a resonance excited in the second cavity at specific frequency. Under high sound pressure level incoming waves, the basic characteristics of the acoustic performance remain. However, vortex shedding transpires at the resonances around both the slits and the drainage slot. Vorticity contours show that the connection of two coupled cavities decreases the strength of vortex shedding around the basic Helmholtz resonance due to a higher energy reflection. Meanwhile, the cell interaction significantly increases the vorticity magnitude near the extra resonant frequency. Finally, a semi-empirical model is derived to predict the extra attenuation peak frequency.

Slotted Photonic Crystal Sensors

Science.gov (United States)

Scullion, Mark G.; Krauss, Thomas F.; Di Falco, Andrea

2013-01-01

Optical biosensors are increasingly being considered for lab-on-a-chip applications due to their benefits such as small size, biocompatibility, passive behaviour and lack of the need for fluorescent labels. The light guiding mechanisms used by many of them results in poor overlap of the optical field with the target molecules, reducing the maximum sensitivity achievable. This review article presents a new platform for optical biosensors, namely slotted photonic crystals, which provide higher sensitivities due to their ability to confine, spatially and temporally, the optical mode peak within the analyte itself. Loss measurements showed values comparable to standard photonic crystals, confirming their ability to be used in real devices. A novel resonant coupler was designed, simulated, and experimentally tested, and was found to perform better than other solutions within the literature. Combining with cavities, microfluidics and biological functionalization allowed proof-of-principle demonstrations of protein binding to be carried out. Higher sensitivities were observed in smaller structures than possible with most competing devices reported in the literature. This body of work presents slotted photonic crystals as a realistic platform for complete on-chip biosensing; addressing key design, performance and application issues, whilst also opening up exciting new ideas for future study. PMID:23503295

Slotted Photonic Crystal Sensors

Directory of Open Access Journals (Sweden)

Andrea Di Falco

2013-03-01

Full Text Available Optical biosensors are increasingly being considered for lab-on-a-chip applications due to their benefits such as small size, biocompatibility, passive behaviour and lack of the need for fluorescent labels. The light guiding mechanisms used by many of them results in poor overlap of the optical field with the target molecules, reducing the maximum sensitivity achievable. This review article presents a new platform for optical biosensors, namely slotted photonic crystals, which provide higher sensitivities due to their ability to confine, spatially and temporally, the optical mode peak within the analyte itself. Loss measurements showed values comparable to standard photonic crystals, confirming their ability to be used in real devices. A novel resonant coupler was designed, simulated, and experimentally tested, and was found to perform better than other solutions within the literature. Combining with cavities, microfluidics and biological functionalization allowed proof-of-principle demonstrations of protein binding to be carried out. Higher sensitivities were observed in smaller structures than possible with most competing devices reported in the literature. This body of work presents slotted photonic crystals as a realistic platform for complete on-chip biosensing; addressing key design, performance and application issues, whilst also opening up exciting new ideas for future study.

Low profile frequency agile MIMO slot antenna with TCM characterization

KAUST Repository

Ghalib, Asim

2017-06-07

In this paper, a frequency reconfigurable multiple-input-multiple-output (MIMO) slot antenna is presented. The proposed design is low profile and compact with wide tunability range, covering several well-known frequency bands from 1800 MHz to 2450 MHz. The frequency reconfigurability is achieved by loading the annular slot with varactor diodes. The antenna system is also analyzed for MIMO performance metrics. Moreover, the effect of circular slot antenna on the chassis modes is also investigated using the theory of characteristic modes (TCM). The physical principle behind frequency reconfigurability is also investigated using TCM analysis. An interesting finding is observed using varactor diodes for frequency reconfigurability, that is the reactive impedance loading does not alter the modal significance (MS) plots but only aid in the input impedance matching at different frequency bands.

Wideband Circularly Polarized Printed Ring Slot Antenna for 5 GHz – 6 GHz

Science.gov (United States)

Nasrun Osman, Mohamed; Rahim, Mohamad Helmi A.; Jusoh, Muzammil; Sabapathy, Thennarasan; Rahim, Mohamad Kamal A.; Norlyana Azemi, Saidatul

2018-03-01

This paper presents the design of circularly polarized printed slot antenna operating at 5 – 6 GHz. The proposed antenna consists of L-shaped feedline on the top of structure and circular ring slot positioned at the ground plane underneath the substrate as a radiator. A radial and narrow slot in the ground plane provides coupling between the L-shaped feedline and circular ring slot. The circular polarization is realized by implementing the slits perturbation located diagonally to perturb the current flow on the slot structure. The antenna prototype is fabricated on FR4 substrate. The simulated and measured results are compared and analyzed to demonstrate the performance of the antenna. Good measured of simulated results are obtained at the targeted operating frequency. The simulated -10dB reflection coefficient bandwidths and axial ratio are 750 MHz and 165 MHz, respectively. The investigation on the affect of the important parameters towards the reflection coefficient and axial are also presented. The proposed antenna is highly potential to be used for wireless local area network (WLAN) and wireless power transfer (WPT).

Modeling arbitrarily directed slots that are narrow both in width and depth with regard to the FDTD spatial cell

Energy Technology Data Exchange (ETDEWEB)

Riley, D.J.; Turner, C.D.

1991-12-31

The Hybrid Thin-Slot Algorithm (HTSA) integrates a transient integral-equation solution for an aperture in an infinite plane into a finite-difference time-domain (FDTD) code. The technique was introduced for linear apertures and was extended to include wall loss and lossy internal gaskets. A general implementation for arbitrary thin slots is briefly described here. The 3-D FDTD-code TSAR was selected for the implementation. The HTSA does not provide universal solutions to the narrow slot problem, but has merits appropriate for particular applications. The HTSA is restricted to planar slots, but can solve the important case that both the width and depth of the slot are narrow compared to the FDTD spatial cell. IN addition, the HTSA is not bound to the FDTD discrete spatial and time increments, and therefore, high-resolution solutions for the slot physics are possible. The implementation of the HTSA into TSAR is based upon a ``slot data file`` that includes the cell indices where the desired slots are exist within the FDTD mesh. For an HTSA-defined slot, the wall region local to the slot is shorted, and therefore, to change the slot`s topology simply requires altering the file to include the desired cells. 7 refs.

Topology of surfaces for molecular Stark energy, alignment, and orientation generated by combined permanent and induced electric dipole interactions.

Science.gov (United States)

Schmidt, Burkhard; Friedrich, Bretislav

2014-02-14

We show that combined permanent and induced electric dipole interactions of linear polar and polarizable molecules with collinear electric fields lead to a sui generis topology of the corresponding Stark energy surfaces and of other observables - such as alignment and orientation cosines - in the plane spanned by the permanent and induced dipole interaction parameters. We find that the loci of the intersections of the surfaces can be traced analytically and that the eigenstates as well as the number of their intersections can be characterized by a single integer index. The value of the index, distinctive for a particular ratio of the interaction parameters, brings out a close kinship with the eigenproperties obtained previously for a class of Stark states via the apparatus of supersymmetric quantum mechanics.

ATLAS Cold Leg Top Slot Break Analysis using RELAP5

Energy Technology Data Exchange (ETDEWEB)

Sung, Haejung; Lee, Sang Ik; Park, Ju-Hyun; Choi, Tong-Soo [KEPCO NF, Daejeon (Korea, Republic of)

2016-10-15

U.S. Nuclear Regulatory Commission (US-NRC) has been reviewing the design certification application for APR1400 submitted by Korea Electric Power Corporation (KEPCO). The main concern about cold leg top slot break is that cladding temperature might be increased by core uncover due to four loop seal reformation following flooding of safety injection water. An integral effect test for cold leg top slot break was performed by KAERI (Korea Atomic Energy Research Institute) using ATLAS (Advanced Thermal-Hydraulic Test Loop for Accident Simulation), which is a scaled down experimental facility for APR1400. In this study, RELAP5/MOD3.3/Patch04 is assessed by experimental result of ATLAS cold leg top slot break. Also, thermal hydraulic phenomena by four loop seals reformation is observed by RELAP5 result. The RELAP5/MOD3.3/Patch04 is assessed by the experimental result of ATLAS cold leg top slot break. The top slot break is described by offtake model, and the mass flow rate is fairly well estimated. The RELAP5 well predicts the correlation between general trend and four loop seal reformation. The pressure of the core region and the cladding temperature tends to increase during four loop seal reformation due to steam path blockage on four loop seals. It is presumed that the code cannot estimate two phase phenomena by loop seal clearing as same as experiments. In terms of cladding temperature, loop seal reformation due to loop seal elevation of APR1400 does not need to be the issue, since the void fraction at the active top core is maintained over 0.4.

Fleet Planning Decision-Making: Two-Stage Optimization with Slot Purchase

Directory of Open Access Journals (Sweden)

Lay Eng Teoh

2016-01-01

Full Text Available Essentially, strategic fleet planning is vital for airlines to yield a higher profit margin while providing a desired service frequency to meet stochastic demand. In contrast to most studies that did not consider slot purchase which would affect the service frequency determination of airlines, this paper proposes a novel approach to solve the fleet planning problem subject to various operational constraints. A two-stage fleet planning model is formulated in which the first stage selects the individual operating route that requires slot purchase for network expansions while the second stage, in the form of probabilistic dynamic programming model, determines the quantity and type of aircraft (with the corresponding service frequency to meet the demand profitably. By analyzing an illustrative case study (with 38 international routes, the results show that the incorporation of slot purchase in fleet planning is beneficial to airlines in achieving economic and social sustainability. The developed model is practically viable for airlines not only to provide a better service quality (via a higher service frequency to meet more demand but also to obtain a higher revenue and profit margin, by making an optimal slot purchase and fleet planning decision throughout the long-term planning horizon.

Assessment of bracket surface morphology and dimensional change

Directory of Open Access Journals (Sweden)

Pillai Devu Radhakrishnan

2017-01-01

Full Text Available Objective: The objective of this study was to compare the surface morphology and dimensional stability of the bracket slot at the onset of treatment and after 12 months of intraoral exposure. The study also compared the amount of calcium at the bracket base which indicates enamel loss among the three orthodontic brackets following debonding after 12 months of intraoral exposure. Materials and Methods: The sample consisted of 60 (0.022” MBT canine brackets. They were divided into three groups: self-ligating, ceramic bracket with metal slot, and stainless steel (SS brackets. The slot dimensions, micromorphologic characteristics of as-received and retrieved brackets were measured with a stereomicroscope and scanning electron microscope (SEM, respectively. The amount of calcium at the bracket base which indicates enamel damage was quantified using energy-dispersive X-ray spectrometry (EDX. Results: The results showed statistically significant alterations (P < 0.05 in the right vertical dimension, internal tie wing width (cervical, right and left depth of the slot (Kruskal–Wallis test. Multiple comparison using Mann–Whitney test showed that ceramic brackets underwent (P < 0.05 minimal alterations in the right vertical dimension, internal tie wing width (cervical, right and left depth of the slot (0.01 mm, −0.003 mm, 0.006 mm, −0.002 mm, respectively when compared with the changes seen in SS and self-ligating brackets. SEM analysis revealed an increase in the surface roughness of ceramic with metal slot brackets and self-ligating bracket showed the least irregularity. The presence of calcium was noted on all evaluated brackets under EDX, but ceramic with metal slot brackets showed a significantly greater amount of enamel loss (P = 0.001. Conclusion: Ceramic brackets were found to be dimensionally stable when compared to SS and self-ligating. Self-ligating bracket showed minimal surface irregularity. Ceramic with metal slot brackets showed a

Extremely High-Birefringent Asymmetric Slotted-Core Photonic Crystal Fiber in THz Regime

DEFF Research Database (Denmark)

Islam, Raonaqul; Habib, Selim; Hasanuzzaman, G.K.M.

2015-01-01

We present a thorough numerical analysis of a highly birefringent slotted porous-core circular photonic crystal fiber (PCF) for terahertz (THz) wave guidance. The slot shaped air-holes break the symmetry of the porous-core which offers a very high birefringence whereas the compact geometry of the...

Metal membrane with dimer slots as a universal polarizer

DEFF Research Database (Denmark)

Zhukovsky, Sergei; Zalkovskij, Maksim; Malureanu, Radu

2014-01-01

In this work, we show theoretically and confirm experimentally that thin metal membranes patterned with an array of slot dimers (or their Babinet analogue with metal rods) can function as a versatile spectral and polarization filter. We present a detailed covariant multipole theory for the electr......In this work, we show theoretically and confirm experimentally that thin metal membranes patterned with an array of slot dimers (or their Babinet analogue with metal rods) can function as a versatile spectral and polarization filter. We present a detailed covariant multipole theory...

Structural looseness investigation in slow rotating permanent magnet generators

DEFF Research Database (Denmark)

Skrimpas, Georgios Alexandros; Mijatovic, Nenad; Sweeney, Christian Walsted

2016-01-01

Structural looseness in electric machines is a condition influencing the alignment of the machine and thus the overall bearing health. In this work, assessment of the above mentioned failure mode is tested on a slow rotating (running speed equal to 0.7Hz) permanent magnet generator (PMG), while...... collecting vibration and current data in order to cross-reference the indications from the two monitoring techniques. It is found that electric signature analysis shows no response even when two hold down bolts are untightened, whereas the analysis results from the vibration data exhibit superior performance....... The vibration-based condition indicators with the best response are the stator slot pass frequency, which can be directly related to the cogging torque in PMGs, and the 4th electric frequency harmonic, whose amplitudes increase due to the overall lower structure damping coefficient under looseness...

Thin concentrator photovoltaic module with micro-solar cells which are mounted by self-align method using surface tension of melted solder

Science.gov (United States)

Hayashi, Nobuhiko; Terauchi, Masaharu; Aya, Youichirou; Kanayama, Shutetsu; Nishitani, Hikaru; Nakagawa, Tohru; Takase, Michihiko

2017-09-01

We are developing a thin and lightweight CPV module using small size lens system made from poly methyl methacrylate (PMMA) with a short focal length and micro-solar cells to decrease the transporting and the installing costs of CPV systems. In order to achieve high conversion efficiency in CPV modules using micro-solar cells, the micro-solar cells need to be mounted accurately to the irradiated region of the concentrated sunlight. In this study, we have successfully developed self-align method thanks to the surface tension of the melted solder even utilizing commercially available surface-mounting technology (SMT). Solar cells were self-aligned to the specified positions of the circuit board by this self-align method with accuracy within ±10 µm. We actually fabricated CPV modules using this self-align method and demonstrated high conversion efficiency of our CPV module.

14 CFR 93.218 - Slots for transborder service to and from Canada.

Science.gov (United States)

2010-01-01

... Canada. 93.218 Section 93.218 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF... service to and from Canada. (a) Except as otherwise provided in this subpart, international slots...'Hare in the Winter season. (c) Any modification to the slot base by the Government of Canada or the...

A peer review of the Hanford Site Permanent Isolation Surface Barrier Development Program

International Nuclear Information System (INIS)

Wing, N.R.

1992-09-01

A panel of technical experts was organized to peer review the Hanford Site Permanent Isolation Surface Barrier Development Program (BDP) and to provide a specific review of a preconceptual prototype barrier design initiated during fiscal year (FY) 1990. The technical peer review of the BDP and the prototype is being conducted in three phases, two of which have been completed. This document presents the peer review panel's findings on the first two phases of the peer review process. Biointrusion and water intrusion control are discussed, along with design life, vegetation, and climate impact

Hole-thru-laminate mounting supports for photovoltaic modules

Science.gov (United States)

Wexler, Jason; Botkin, Jonathan; Culligan, Matthew; Detrick, Adam

2015-02-17

A mounting support for a photovoltaic module is described. The mounting support includes a pedestal having a surface adaptable to receive a flat side of a photovoltaic module laminate. A hole is disposed in the pedestal, the hole adaptable to receive a bolt or a pin used to couple the pedestal to the flat side of the photovoltaic module laminate.

Topology of surfaces for molecular Stark energy, alignment, and orientation generated by combined permanent and induced electric dipole interactions

Energy Technology Data Exchange (ETDEWEB)

Schmidt, Burkhard, E-mail: burkhard.schmidt@fu-berlin.de [Institute for Mathematics, Freie Universität Berlin, Arnimallee 6, D-14195 Berlin (Germany); Friedrich, Bretislav, E-mail: brich@fhi-berlin.mpg.de [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin (Germany)

2014-02-14

We show that combined permanent and induced electric dipole interactions of linear polar and polarizable molecules with collinear electric fields lead to a sui generis topology of the corresponding Stark energy surfaces and of other observables – such as alignment and orientation cosines – in the plane spanned by the permanent and induced dipole interaction parameters. We find that the loci of the intersections of the surfaces can be traced analytically and that the eigenstates as well as the number of their intersections can be characterized by a single integer index. The value of the index, distinctive for a particular ratio of the interaction parameters, brings out a close kinship with the eigenproperties obtained previously for a class of Stark states via the apparatus of supersymmetric quantum mechanics.

A piezoelectric ultrasonic linear micromotor using a slotted stator.

Science.gov (United States)

Yun, Cheol-Ho; Watson, Brett; Friend, James; Yeo, Leslie

2010-08-01

A novel ultrasonic micro linear motor that uses 1st longitudinal and 2nd bending modes, derived from a bartype stator with a rectangular slot cut through the stator length, has been proposed and designed for end-effect devices of microrobotics and bio-medical applications. The slot structure plays an important role in the motor design, and can be used not only to tune the resonance frequency of the two vibration modes but also to reduce the undesirable longitudinal coupling displacement caused by bending vibration at the end of the stator. By using finite element analysis, the optimal slot dimension to improve the driving tip motion was determined, resulting in the improvement of the motor performance. The trial linear motor, with a weight of 1.6 g, gave a maximum driving velocity of 1.12 m/s and a maximum driving force of 3.4 N. A maximum mechanical output power of 1.1 W was obtained at force of 1.63 N and velocity of 0.68 m/s. The output mechanical power per unit weight was 688 W/kg.

Electromagnetic Comparison of 3-, 5- and 7-phases Permanent-Magnet Synchronous Machines : Mild Hybrid Traction Application

Directory of Open Access Journals (Sweden)

D. Ouamara

2016-09-01

Full Text Available Authors compare the electromagnetic performances of three multi-phases permanent-magnet (PM synchronous machines (PMSM for Mild Hybridtraction application. This comparison was made using two-dimensional (2-D numerical simulations in transient magnetic with eddy-current reaction field in the PMs. The best machine was determined using an energetic analysis (i.e., losses, torque and efficiency according specifications. In this study, the non-overlapping winding with double layer (i.e. all teeth wound type was used. The winding synthesis is based on the "Star of slots" method as well as the Fourier series decomposition of the magnetomotive force (MMF.

Seawave Slot-Cone Generator

DEFF Research Database (Denmark)

Vicinanza, Diego; Margheritini, Lucia; Contestabile, Pasquale

2009-01-01

This paper discusses a new type of Wave Energy Converter (WEC) named Seawave Slot-Cone Generator (SSG). The SSG is a WEC of the overtopping type. The structure consists of a number of reservoirs one on the top of each others above the mean water level in which the water of incoming waves is store...... on sloping walls constituting the structure. The research is intended to be of direct use to engineers analyzing design and stability of this peculiar kind of coastal structure....

Ka-Band Slot-Microstrip-Covered and Waveguide-Cavity-Backed Monopulse Antenna Array

Directory of Open Access Journals (Sweden)

Li-Ming Si

2014-01-01

Full Text Available A slot-microstrip-covered and waveguide-cavity-backed monopulse antenna array is proposed for high-resolution tracking applications at Ka-band. The monopulse antenna array is designed with a microstrip with 2×32 slots, a waveguide cavity, and a waveguide monopulse comparator, to make the structure simple, reduce the feeding network loss, and increase the frequency bandwidth. The 2×32 slot-microstrip elements are formed by a metal clad dielectric substrate and slots etched in the metal using the standard printed circuit board (PCB process with dimensions of 230 mm  ×  10 mm. The proposed monopulse antenna array not only maintains the advantages of the traditional waveguide slot antenna array, but also has the characteristics of wide bandwidth, high consistence, easy of fabrication, and low cost. From the measured results, it exhibits good monopulse characteristics, including the following: the maximum gains of sum pattern are greater than 24 dB, the 3 dB beamwidth of sum pattern is about 2.2 degrees, the sidelobe levels of the sum pattern are less than −18 dB, and the null depths of the difference pattern are less than −25 dB within the operating bandwidth between 33.65 GHz and 34.35 GHz for VSWR ≤ 2.

Torque Ripple Minimization and Performance Investigation of an In-Wheel Permanent Magnet Motor

Directory of Open Access Journals (Sweden)

A. Mansouri

2016-06-01

Full Text Available Recently, electric vehicle motoring has become a topic of interest, due to the several problems caused by thermal engines such as pollution and high oil prices. Thus, electric motors are increasingly applied in vehicle’ applications and relevant research about these motors and their applications has been performed. Of particular interest are the improvements regarding torque production capability, the minimization of torque ripple and iron losses. The present work deals with the optimum design and the performance investigation of an outer rotor permanent magnet motor for in-wheel electric vehicle application. At first, and in order to find the optimum motor design, a new based particle-swarm multi-objective optimization procedure is applied. Three objective functions are used: efficiency maximization, weight and ripple torque minimization. Secondly, the effects of the permanent magnets segmentation, the stator slots opening, and the separation of adjacent magnets by air are outlined. The aim of the paper is the design of a topology with smooth output torque, low ripple torque, low iron losses and mechanical robustness.

Photocatalytic disinfection of surfaces with copper doped Ti02 nanotube coatings illuminated by ceiling mounted fluorescent light

Science.gov (United States)

Koklic, Tilen; Pintarič, Štefan; Zdovc, Irena; Golob, Majda; Umek, Polona; Mehle, Alma; Dobeic, Martin; Štrancar, Janez

2018-01-01

High economic burden is associated with foodborne illnesses. Different disinfection methods are therefore employed in food processing industry; such as use of ultraviolet light or usage of surfaces with copper-containing alloys. However, all the disinfection methods currently in use have some shortcomings. In this work we show that copper doped TiO2 nanotubes deposited on existing surfaces and illuminated with ceiling mounted fluorescent lights can retard the growth of Listeria Innocua by 80% in seven hours of exposure to the fluorescent lights at different places in a food processing plant or in the laboratory conditions with daily reinocuation and washing. The disinfection properties of the surfaces seem to depend mainly on the temperature difference of the surface and the dew point, where for the maximum effectiveness the difference should be about 3 degrees celsius. The TiO2 nanotubes have a potential to be employed for an economical and continuous disinfection of surfaces. PMID:29768464

Benefits and unexpected artifacts of biplanar digital slot-scanning imaging in children

Energy Technology Data Exchange (ETDEWEB)

Blumer, Steven L. [Nemours/A.I duPont Hospital for Children, Department of Medical Imaging, Wilmington, DE (United States); Dinan, David [Nemours Children' s Hospital, Orlando, FL (United States); Grissom, Leslie E. [Nemours/Alfred I. duPont Hospital for Children, Department of Radiology, Wilmington, DE (United States)

2014-07-15

Biplanar digital slot-scanning allows for relatively low-dose orthopedic imaging, an advantage in imaging children given the growing concerns regarding radiosensitivity. We have used this system for approximately 1 year for orthopedic imaging of the spine and lower extremities. We have noted advantages of using the digital slot-scanning system when compared with computed radiographic and standard digital radiographic imaging systems, but we also found unexpected but common imaging artifacts that are the direct result of the imaging method and that have not been reported. This pictorial essay serves to familiarize radiologists with the advantages of the digital slot-scanning system as well as imaging artifacts common with this new technology. (orig.)

Thermocouple Errors when Mounted on Cylindrical Surfaces in Abnormal Thermal Environments.

Energy Technology Data Exchange (ETDEWEB)

Nakos, James T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Suo-Anttila, Jill M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zepper, Ethan T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Koenig, Jerry J [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Valdez, Vincent A. [ECI Inc., Albuquerque, NM (United States)

2017-05-01

Mineral-insulated, metal-sheathed, Type-K thermocouples are used to measure the temperature of various items in high-temperature environments, often exceeding 1000degC (1273 K). The thermocouple wires (chromel and alumel) are protected from the harsh environments by an Inconel sheath and magnesium oxide (MgO) insulation. The sheath and insulation are required for reliable measurements. Due to the sheath and MgO insulation, the temperature registered by the thermocouple is not the temperature of the surface of interest. In some cases, the error incurred is large enough to be of concern because these data are used for model validation, and thus the uncertainties of the data need to be well documented. This report documents the error using 0.062" and 0.040" diameter Inconel sheathed, Type-K thermocouples mounted on cylindrical surfaces (inside of a shroud, outside and inside of a mock test unit). After an initial transient, the thermocouple bias errors typically range only about +-1-2% of the reading in K. After all of the uncertainty sources have been included, the total uncertainty to 95% confidence, for shroud or test unit TCs in abnormal thermal environments, is about +-2% of the reading in K, lower than the +-3% typically used for flat shrouds. Recommendations are provided in Section 6 to facilitate interpretation and use of the results. .

High-Q silicon-on-insulator slot photonic crystal cavity infiltrated by a liquid

International Nuclear Information System (INIS)

Caër, Charles; Le Roux, Xavier; Cassan, Eric

2013-01-01

We report the experimental realization of a high-Q slot photonic crystal cavity in Silicon-On-Insulator (SOI) configuration infiltrated by a liquid. Loaded Q-factor of 23 000 is measured at telecom wavelength. The intrinsic quality factor inferred from the transmission spectrum is higher than 200 000, which represents a record value for slot photonic crystal cavities on SOI, whereas the maximum of intensity of the cavity is roughly equal to 20% of the light transmitted in the waveguide. This result makes filled slot photonic crystal cavities very promising for silicon-based light emission and ultrafast nonlinear optics

Studies on surface-mounted SiPMs in 2015 testbeam of a highly granular hadron calorimeter

Energy Technology Data Exchange (ETDEWEB)

Krause, Sascha [Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, Mainz (Germany); Collaboration: CALICE-D-Collaboration

2016-07-01

To achieve excellent jet energy resolution, a highly granular hadronic calorimeter is being developed within the CALICE collaboration. Therefore, about 8 million detector units consisting of scintillator tiles and silicon photomultipliers (SiPMs) will be installed in the final HCAL design. The usage of surface-mounted (SMD) SiPMs allows an automated mass assembly. During CERN SPS testbeam 2015, data for a prototype consisting of up to 11 layers of HCAL base units (HBU) was collected using electron, muon and pion beams. One of the layers was equipped with the first SMD HBU. Results and performance, especially of the SMD HBU are presented.

Joint slot allocation and dynamic pricing of container sea–rail multimodal transportation

Directory of Open Access Journals (Sweden)

Di Liu

2015-06-01

Full Text Available The container sea–rail multimodal transport system faces complex challenges with demand uncertainties for joint slot allocation and dynamic pricing. The challenge is formulated as a two-stage optimal model based on revenue management (RM as actual slots sale of multi-node container sea–rail multimodal transport usually includes contract sale to large shippers and free sale to scattered shippers. First stage in the model utilizes an origin-destination control approach, formulated as a stochastic integer programming equation, to settle long-term slot allocation in the contract market and empty container allocation. Second stage in the model is formulated as a stochastic nonlinear programming equation to solve a multiproduct joint dynamic pricing and inventory control problem for price settling and slot allocation in each period of free market. Considering the random nature of demand, the methods of chance constrained programming and robust optimization are utilized to transform stochastic models into deterministic models. A numerical experiment is presented to verify the availability of models and solving methods. Results of considering uncertain/certain demand are compared, which show that the two-stage optimal strategy integrating slot allocation with dynamic pricing considering random demand is revealed to increase the revenue for multimodal transport operators (MTO while concurrently satisfying shippers' demand. Research resulting from this paper will contribute to the theory and practice of container sea–rail multimodal transport revenue management and provide a scientific decision-making tool for MTO.

Impedance of a slotted-pipe kicker

Energy Technology Data Exchange (ETDEWEB)

Zhou, Feng [Academia Sinica, Beijing, BJ (China). Inst. of High Energy Physics

1996-08-01

This paper introduces the principle of a new slotted kicker simply, which is made by using vacuum pipe itself with proper slits as current conductors, and then, presents a rough estimation of its longitudinal and transverse impedance, respectively. Calculation shows that its impedance is reduced significantly compared to our present air-coil kicker. (author)

A fast semi-analytical model for the slotted structure of induction motors with 36/28 stator/rotor slot combination

NARCIS (Netherlands)

Sprangers, R.L.J.; Paulides, J.J.H.; Gysen, B.L.J.; Lomonova, E.A.

2014-01-01

A fast, semi-analyticalmodel for inductionmotors (IMs) with 36/28 stator/rotor slot combination is presented. In comparison to traditional analytical models for IMs, such as lumped parameter, magnetic equivalent circuit and anisotropic layer models, the presented model calculates a continuous

Analytical study of optimal design and gain parameters of double-slot plasmonic waveguides

International Nuclear Information System (INIS)

Handapangoda, Dayan; Rukhlenko, Ivan D; Premaratne, Malin

2013-01-01

We theoretically analyze guided modes in optically active and passive double-slot plasmonic waveguides. We show that for one of the two different mode symmetries supported by the waveguide, a most productive guiding condition can be realized by adjusting the thicknesses of the layers to optimal values. We also derive approximate analytic expressions to calculate the optimal geometrical parameters of the waveguide. Interestingly, our analysis shows that the propagation losses associated with the inverse mode symmetry of the double-slot waveguide are comparatively low, regardless of the dimensions of the waveguide. We further show that the propagation losses become the smallest in the limiting case of a single-slot (metal–dielectric–metal (MDM)) waveguide. For both double- and single-slot waveguides, we show that the gain required to overcome the losses can be reduced by choosing a dielectric with a low refractive index. We also derive accurate analytical expressions to readily estimate the critical gain and modal gain of the waveguides. (paper)

Vertical Slot Convection: A linear study

International Nuclear Information System (INIS)

McAllister, A.; Steinolfson, R.; Tajima, T.

1992-11-01

The linear stability properties of fluid convection in a vertical slot were studied. We use a Fourier-Chebychev decomposition was used to set up the linear eigenvalue problems for the Vertical Slot Convection and Benard problems. The eigenvalues, neutral stability curves, and critical point values of the Grashof number, G, and the wavenumber were determined. Plots of the real and imaginary parts of the eigenvalues as functions of G and α are given for a wide range of the Prandtl number, Pr, and special note is made of the complex mode that becomes linearly unstable above Pr ∼ 12.5. A discussion comparing different special cases facilitates the physical understanding of the VSC equations, especially the interaction of the shear-flow and buoyancy induced physics. Making use of the real and imaginary eigenvalues and the phase properties of the eigenmodes, the eigenmodes were characterized. One finds that the mode structure becomes progressively simpler with increasing Pr, with the greatest complexity in the mid ranges where the terms in the heat equation are of roughly the same size

Examination report: Remote video examination of air slots under the primary tank at 241-AN-107

International Nuclear Information System (INIS)

Pedersen, L.T.

1998-01-01

This report documents the results of remote video examination of air slots in the insulating concrete slab beneath the primary tank at 241-AN-107. Life Extension Equipment Engineering has selected tank 241-AN-107 for ultrasonic evaluation of tank wall, knuckle, and floor plates. Access to the primary tank floor plates is via the air slots which were formed into the insulating concrete slab during tank construction (reference drawings H-2-71105 and H-2-71160). Prior to deployment of the ultrasonic inspection equipment it is desirable to examine the air slots for obstructions and debris which could impede the ultrasonic equipment. The criteria, equipment description, deliverables, and responsibilities for examination of the air slots are described in HNF-1949, Rev. 0, ''Engineering Task Plan for Remote Video Examination of Air Slots Under the Primary Tank at 241-AN-107''

Incorporation of the stress concentration slots into the flexures for a high-performance microaccelerometer

International Nuclear Information System (INIS)

Zhao Yulong; Sun Lu; Liu Yan; Wang Weizhong; Tian Bian

2012-01-01

Presented in this paper is a development of a high-performance piezoresistive microaccelerometer based on the slot etching in the quad flexures for the vibration detection of high speed spindle. The proposed structure consists of a proof mass supported by four thin flexures with slots etched in the middle. Boron diffused piezoresistors located near the stress concentration regions are used for sensing the localized stress resulting from the incorporation of the slots into the flexures. Theoretical analysis and finite element analysis show satisfactory results of an improved sensitivity and favorable natural frequency higher than 10 kHz, conforming to the initial design requirements. The microfabrication techniques are described to prototype the two accelerometer chips, one with slots and the other one without slots. The tested microaccelerometers with 3 V DC power supply show an average sensitivity of 0.424 mV/g normal to the proof mass plane, increased by 60.6% than the ones without slots. An average transverse sensitivity is found to be 9.2 μV/g along X axis and 14.2 μV/g along Y axis, either of which is less than 3.5% of prime-axis sensitivity. Concerning the resonant frequency, dynamic experiment shows about 12.46 kHz and is available for the proposed design with a tiny loss of 3.5% compared with the quad-beam design. When taking the product of sensitivity and natural frequency as judgment criteria, an inspiring increase by 28.6% of the figure of merit is accomplished for the proposed accelerometer. Overall, the findings of this study confirm the feasibility of incorporating slots into the conventional configurations to improve the sensor sensitivity while maintaining a comparatively high natural frequency.

A numerical investigation on the effects of slot geometry on shock boundary layer interaction

Energy Technology Data Exchange (ETDEWEB)

Bazazzadeh, M.; Menshadi, M. D.; Karbasizadeh, M. [Dept. of Mechanical and Aerospace Engineering, Malek Ashtar University of Technology, Esfahan (Turkmenistan)

2017-01-15

Slot is one of the features that control Shock wave-boundary layer interaction (SBLI), which is generally used to prevent strong interference from shockwaves to the boundary layer in supersonic flows. With this feature, the height of the triple point of λ shock significantly increases, and this increase causes a decline in shock power and pressure drop rate. In the current paper, the main focus is on the monitoring of the geometrical effect of slot as an influential parameter on the structure of the shock and flow characteristics by using numerical methods. Therefore, the averaged implicit Navier-Stokes equations and two equation standard k-ω turbulence models for the numerical simulation of the flow field have been used. Results indicate that the numerical results are fairly consistent with the experimental data. Because of the increase in the number of slots (n), and the leading leg of the λ shock is located within the slot, the height of the triple point increases. However, because of the increasing drops due to viscosity, the total pressure changes are negligible. In addition, with an increase in this parameter, changes in the static pressure caused by the leading leg of the shock have increased. By increasing the width of the slots, the height of the triple point has had an upward trend up to s = 8 mm and then had nearly constant values. In this mode, the static pressure changes resulting from the leading leg of the shock are negligible. For increasing the number or the width of slots, the re-expansion waves formed within the slot are removed because of the reduction in the severity of the changes in the boundary layer. To simulate and compare the results with the data obtained from the experimental tests, results from the Cambridge University's wind tunnel tests have been used.

Immunolocalization of RANK and RANKL along the root surface and in the periodontal membrane of human primary and permanent teeth

DEFF Research Database (Denmark)

Bille, Marie-Louise Bastholm; Thomsen, Bjarke; Andersen, Thomas Levin

2012-01-01

Abstract Objective. Root resorption, impaired tooth eruption and early tooth loss have been described in relation to diseases that involve defects in the RANK-RANKL-OPG-expression. The aim of the present immunhistochemical study was to localize and compare the reactions for RANK and membrane...... in odontoblasts and in cells along denticles in one primary tooth. RANK was located in mononuclear cells in the pulp and in multinucleated odontoclasts along resorbed root surfaces and along resorbed dentin surfaces in the pulp in primary teeth and one permanent tooth. Conclusions. This study demonstrated RANK...... positivity in resorption areas in primary and permanent teeth. RANKL was positive in the pulp of one primary tooth. RANK expression in odontoclasts and RANKL expression in the pulp may indicate that RANK/RANKL play a role during resorption....

Dynamic and steady state performance comparison of line-start permanent magnet synchronous motors with interior and surface rotor magnets

Directory of Open Access Journals (Sweden)

Ogbuka Cosmas

2016-03-01

Full Text Available A comprehensive comparison of the dynamic and steady state performance characteristics of permanent magnet synchronous motors (PMSM with interior and surface rotor magnets for line-start operation is presented. The dynamic model equations of the PMSM, with damper windings, are utilized for dynamic studies. Two typical loading scenarios are examined: step and ramp loading. The interior permanent magnet synchronous motor (IPMSM showed superior asynchronous performance under no load, attaining faster synchronism compared to the surface permanent magnet synchronous motor (SPMSM. With step load of 10 Nm at 2 s the combined effect of the excitation and the reluctance torque forced the IPMSM to pull into synchronism faster than the SPMSM which lacks saliency. The ability of the motors to withstand gradual load increase, in the synchronous mode, was examined using ramp loading starting from zero at 2 s. SPMSM lost synchronism at 12 s under 11 Nm load while the IPMSM sustained synchronism until 41 seconds under 40 Nm load. This clearly suggests that the IPMSM has superior load-withstand capability. The superiority is further buttressed with the steady state torque analysis where airgap torque in IPMSM is enhanced by the reluctance torque within 90° to 180° torque angle.

Airflow and Heat Transfer in the Slot-Vented Room with Radiant Floor Heating Unit

Directory of Open Access Journals (Sweden)

Xiang-Long Liu

2012-01-01

Full Text Available Radiant floor heating has received increasing attention due to its diverse advantages, especially the energy saving as compared to the conventional dwelling heating system. This paper presents a numerical investigation of airflow and heat transfer in the slot-vented room with the radiant floor heating unit. Combination of fluid convection and thermal radiation has been implemented through the thermal boundary conditions. Spatial distributions of indoor air temperature and velocity, as well as the heat transfer rates along the radiant floor and the outer wall, have been presented and analyzed covering the domains from complete natural convection to forced convection dominated flows. The numerical results demonstrate that the levels of average temperature in the room with lateral slot-ventilation are higher than those without slot-ventilation, but lower than those in the room with ceiling slot-ventilation. Overall, the slot-ventilation room with radiant floor heating unit could offer better indoor air quality through increasing the indoor air temperature and fresh air exchanging rate simultaneously. Concerning the airborne pollutant transports and moisture condensations, the performance of radiant floor heating unit will be further optimized in our future researches.

Slotted coax as a beam electrode

International Nuclear Information System (INIS)

Lambertson, G.R.; Kim, K.J.; Voelker, F.V.

1983-03-01

The slot coupled TEM line has been employed at CERN as a pick up electrode in the GHz range. It is a compact and broad band device, and will be quite attractive if the coupling efficiency is competitive with an array of quarter wave loops. In this paper, we study various properties of such a structure

Stall inception and warning in a single-stage transonic axial compressor with axial skewed slot casing treatment

International Nuclear Information System (INIS)

Lim, Byeung Jun; Kwon, Se Jin; Park, Tae Choon

2014-01-01

Characteristic changes in the stall inception in a single-stage transonic axial compressor with an axial skewed slot casing treatment were investigated experimentally. A rotating stall occurred intermittently in a compressor with an axial skewed slot, whereas spike-type rotating stalls occurred in the case of smooth casing. The axial skewed slot suppressed stall cell growth and increased the operating range. A mild surge, the frequency of which is the Helmholtz frequency of the compressor system, occurred with the rotating stall. The irregularity in the pressure signals at the slot bottom increased decreasing flow rate. An autocorrelation-based stall warning method was applied to the measured pressure signals. Results estimate and warn against the stall margin in a compressor with an axial skewed slot.

PIV study of large-scale flow organisation in slot jets

International Nuclear Information System (INIS)

Shestakov, Maxim V.; Dulin, Vladimir M.; Tokarev, Mikhail P.; Sikovsky, Dmitrii Ph.; Markovich, Dmitriy M.

2015-01-01

Highlights: • Volumetric velocity measurements are perfumed by PIV to analyse 3D flow organisation in a slot jet. • Proper orthogonal decomposition is used to extract coherent flow motion. • Movement of quasi-two-dimensional large-scale vortices is associated with jet meandering. • Amplitude of jet meandering is found to be aperiodically modulated. • Secondary longitudinal vortex rolls are important for cross-stream mixing and momentum transfer. - Abstract: The paper reports on particle image velocimetry (PIV) measurements in turbulent slot jets bounded by two solid walls with the separation distance smaller than the jet width (5–40%). In the far-field such jets are known to manifest features of quasi-two dimensional, two component turbulence. Stereoscopic and tomographic PIV systems were used to analyse local flows. Proper orthogonal decomposition (POD) was applied to extract coherent modes of the velocity fluctuations. The measurements were performed both in the initial region close to the nozzle exit and in the far fields of the developed turbulent slot jets for Re ⩾ 10,000. A POD analysis in the initial region indicates a correlation between quasi-2D vortices rolled-up in the shear layer and local flows in cross-stream planes. While the near-field turbulence shows full 3D features, the wall-normal velocity fluctuations day out gradually due to strong wall-damping resulting in an almost two-component turbulence. On the other hand, the longitudinal vortex rolls take over to act as the main agents in wall-normal and spanwise mixing and momentum transfer. The quantitative analysis indicates that the jet meandering amplitude was aperiodically modulated when arrangement of the large-scale quasi-2D vortices changed between asymmetric and symmetric pattern relatively to the jet axis. The paper shows that the dynamics of turbulent slot jets are more complex than those of 2D, plane and rectangular 3D jets. In particular, the detected secondary longitudinal

Semi-automatic parking slot marking recognition for intelligent parking assist systems

Directory of Open Access Journals (Sweden)

Ho Gi Jung

2014-01-01

Full Text Available This paper proposes a semi-automatic parking slot marking-based target position designation method for parking assist systems in cases where the parking slot markings are of a rectangular type, and its efficient implementation for real-time operation. After the driver observes a rearview image captured by a rearward camera installed at the rear of the vehicle through a touchscreen-based human machine interface, a target parking position is designated by touching the inside of a parking slot. To ensure the proposed method operates in real-time in an embedded environment, access of the bird's-eye view image is made efficient: image-wise batch transformation is replaced with pixel-wise instantaneous transformation. The proposed method showed a 95.5% recognition rate in 378 test cases with 63 test images. Additionally, experiments confirmed that the pixel-wise instantaneous transformation reduced execution time by 92%.

[The characteristics of and social support for pathological gamblers among "pachinko" or "slot" users in Japan].

Science.gov (United States)

Kumagami, Takashi

2014-01-01

In Japan, there are one to two million people suspected of being pathological gamblers according to the definition in DSM-IV-TR. Almost all of them use "pachinko" or "slot," which are gambling stores, throughout Japan, that number 12,000 in total. However, the characteristics and ratio of pathological "pachinko" and "slot" gamblers have not been investigated. The author aimed to determine the characteristics, ratio, and social support available for these users. The author administered an internet survey for users of "pachinko" or "slot." Two hundred and fifty users visited "pachinko" or "slot" stores more than twice a week, and 250 users visited once a week or once a month. The Japanese version of the South Oaks Gambling Screen was administered, and gamblers were asked about their awareness of pathological gambling and the condition of their social support. The author observed that 70.2% of "pachinko" or "slot" users were suspected pathological gamblers and 28.6% of "pachinko" or "slot" users were severe gamblers. A total of 39.3% of them were aware of their pathological gambling, and 6.5% of users who had awareness of pathological gambling had social support. However, most of their social support consisted of family and friends, and almost none of them attended psychiatric clinics, community health centers, or self-help groups like gamblers anonymous. Almost all "pachinko" or "slot" users were suspected of being pathological or severe gamblers. However, they did not approach psychiatric facilities or self-help groups. The author strongly recommends the need for educational programs in junior or high school to prevent future pathological gambling, and create awareness of the dangers of pathological gambling through TV commercials and "pachinko" or "slot" stores. Pathological gambling is a disease that afflicts many people; hence, psychiatric and social welfare professionals should continue to stress the dangers of and offer prevention programs for "pachinko" or

Comparison of static friction with self-ligating, modified slot design and conventional brackets.

Science.gov (United States)

Castro, Raquel Morais; Neto, Perrin Smith; Horta, Martinho Campolina Rebello; Pithon, Matheus Melo; Oliveira, Dauro Douglas

2013-01-01

To compare the static frictional forces generated at the bracket/wire interface of stainless steel brackets with different geometries and angulations, combined with orthodontic wires of different diameters. The frictional forces were evaluated with three different types of metal brackets: a passive self-ligating (SmartClipTM, 3M/Unitek, Monrovia, USA), with a modified slot design (Mini Uni TwinTM, 3M/Unitek, Monrovia, USA) and conventional (Kirium, Abzil, São José do Rio Preto, Brazil). The samples were mounted in a testing device with three different angulations and tested with 0.014" and 0.018" stainless steel wires (American Orthodontics, Sheboygan, USA). The static frictional force was measured using a universal testing machine (DL 500, EMIC®, São José dos Pinhais, Brazil) with a crosshead speed of 1 mm/min. Statistical analysis was performed by two-way ANOVA followed by Bonferroni's post hoc test. There was a significant difference (pstatic friction when the three types of brackets were tested with the same wire size. The wire diameter influenced friction only when the brackets had a 10º angulation (pfriction (pstatic frictional force values between the conventional and self-ligating brackets tested.

Pathological gambling: A comparison of gambling at German-style slot machines and "Classical" gambling.

Science.gov (United States)

Fabian, T

1995-09-01

German-style slot machines and related legal issues are described. On the basis of a survey on 437 members of self-help groups (Gamblers Anonymous) in Germany, slot machine gamblers were compared with casino gamblers on such variables as sociodemographic data, gambling behaviour, financial expenditure, emotional experience while gambling, symptoms of pathological gambling, psychosocial consequences and gambling related delinquency. The casino gamblers' gambling behaviour is financially more extensive. There were similarities regarding the emotional intensity of the gambling experience. However the casino gamblers show more pronounced symptoms of pathological gambling and the psychosocial consequences of their gambling behaviour are more severe. In spite of these differences, the data show that for young people slot machines can be as stimulating and therefore as dangerous as casino gambling. The young slot machine gambler runs a similar risk of acquiring a pathological gambling habit as the casino gambler.

Volcano dome dynamics at Mount St. Helens: Deformation and intermittent subsidence monitored by seismicity and camera imagery pixel offsets

Science.gov (United States)

Salzer, Jacqueline T.; Thelen, Weston A.; James, Mike R.; Walter, Thomas R.; Moran, Seth C.; Denlinger, Roger P.

2016-01-01

The surface deformation field measured at volcanic domes provides insights into the effects of magmatic processes, gravity- and gas-driven processes, and the development and distribution of internal dome structures. Here we study short-term dome deformation associated with earthquakes at Mount St. Helens, recorded by a permanent optical camera and seismic monitoring network. We use Digital Image Correlation (DIC) to compute the displacement field between successive images and compare the results to the occurrence and characteristics of seismic events during a 6 week period of dome growth in 2006. The results reveal that dome growth at Mount St. Helens was repeatedly interrupted by short-term meter-scale downward displacements at the dome surface, which were associated in time with low-frequency, large-magnitude seismic events followed by a tremor-like signal. The tremor was only recorded by the seismic stations closest to the dome. We find a correlation between the magnitudes of the camera-derived displacements and the spectral amplitudes of the associated tremor. We use the DIC results from two cameras and a high-resolution topographic model to derive full 3-D displacement maps, which reveals internal dome structures and the effect of the seismic activity on daily surface velocities. We postulate that the tremor is recording the gravity-driven response of the upper dome due to mechanical collapse or depressurization and fault-controlled slumping. Our results highlight the different scales and structural expressions during growth and disintegration of lava domes and the relationships between seismic and deformation signals.

Advanced hybrid query tree algorithm based on slotted backoff mechanism in RFID

Directory of Open Access Journals (Sweden)

XIE Xiaohui

2013-12-01

Full Text Available The merits of performance quality for a RFID system are determined by the effectiveness of tag anti-collision algorithm.Many algorithms for RFID system of tag identification have been proposed,but they all have obvious weaknesses,such as slow speed of identification,unstable and so on.The existing algorithms can be divided into two groups,one is based on ALOHA and another is based on query tree.This article is based on the hybrid query tree algorithm,combined with a slotted backoff mechanism and a specific encoding (Manchester encoding.The number of value“1” in every three consecutive bits of tags is used to determine the tag response time slots,which will greatly reduce the time slot of the collision and improve the recognition efficiency.

Finite element analysis of slot wall deformation in stainless steel and titanium orthodontic brackets during simulated palatal root torque.

Science.gov (United States)

Magesh, Varadaraju; Harikrishnan, Pandurangan; Kingsly Jeba Singh, Devadhas

2018-04-01

Torque applied on anterior teeth is vital for root positioning and stability. The aim of this study was to evaluate the detailed slot wall deformation in stainless steel (SS) and titanium (Ti) edgewise brackets during palatal root torque using finite element analysis. A finite element model was developed from a maxillary central incisor SS bracket (0.022 in). The generated torque values from an SS rectangular archwire (0.019 × 0.025 in) while twisting from 5° to 40° were obtained experimentally by a spine tester, and the calculated torque force was applied in the bracket slot. The deformations of the slot walls in both SS and Ti brackets were measured at various locations. There were gradual increases in the deformations of both bracket slot walls from the bottom to top locations. In the SS bracket slot for the 40° twist, the deformations were 9.28, 36.8, and 44.8 μm in the bottom, middle, and top slot wall locations, respectively. Similarly, in the Ti bracket slot for the 40° twist, the deformations were 39.2, 62.4, and 76.2 μm in the bottom, middle, and top slot wall locations, respectively. The elastic limits were reached at 28° for SS and at 37° for Ti. Both SS and Ti bracket slots underwent deformation during torque application. There are variations in the deformations at different locations in the slot walls and between the materials. Copyright © 2017 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Evaluation of detectable angle of mid-infrared slot antennas

Science.gov (United States)

Obara, R.; Horikawa, J.; Shimakage, H.; Kawakami, A.

2017-07-01

For evaluations of a mid-infrared (MIR) detectors with antenna, we constructed an angular dependence measurement system of the antenna properties. The fabricated MIR detector consisted of twin slot antennas and a bolometer. The area of the slot antennas was designed to be 2.6 × 0.2 μm2 as to resonate at 61 THz, and they were located parallel and separated 1.6 μm each other. The bolometer was fabricated using by a 7.0-nm thick NbN thin film, and located at the center of the twin antennas. We measured polarization angle dependence and directivity, and showed that the MIR antennas have polarization dependence and directivity like radiofrequency antennas.

Neural network-based adaptive dynamic surface control for permanent magnet synchronous motors.

Science.gov (United States)

Yu, Jinpeng; Shi, Peng; Dong, Wenjie; Chen, Bing; Lin, Chong

2015-03-01

This brief considers the problem of neural networks (NNs)-based adaptive dynamic surface control (DSC) for permanent magnet synchronous motors (PMSMs) with parameter uncertainties and load torque disturbance. First, NNs are used to approximate the unknown and nonlinear functions of PMSM drive system and a novel adaptive DSC is constructed to avoid the explosion of complexity in the backstepping design. Next, under the proposed adaptive neural DSC, the number of adaptive parameters required is reduced to only one, and the designed neural controllers structure is much simpler than some existing results in literature, which can guarantee that the tracking error converges to a small neighborhood of the origin. Then, simulations are given to illustrate the effectiveness and potential of the new design technique.

Clean Air Slots Amid Dense Atmospheric Pollution in Southern Africa

Science.gov (United States)

Hobbs, Peter V.

2003-01-01

During the flights of the University of Washington's Convair-580 in the Southern African Regional Science Initiative (SAFARI 2000) in southern Africa, a phenomenon was observed that has not been reported previously. This was the occurrence of thin layers of remarkably clean air, sandwiched between heavily polluted air, which persisted for many hours during the day. Photographs are shown of these clean air slots (CAS), and particle concentrations and light scattering coefficients in and around such slot are presented. An explanation is proposed for the propensity of CAS to form in southern Africa during the dry season.

Wave Propagation in a coaxial waveguide with a periodic slot array

CERN Document Server

Alesini, D; Garganese, C; Migliorati, M; Palumbo, L

2001-01-01

In this paper we present the numerical and experimental study of the electromagnetic elds that propagate in a coaxial waveguide having periodic slots in the inner conductor. The aim of the work is to estimate the e ects of the holes on the phase velocity of the eld propagating in structures like the LHC liner, and to which extent these elds can be considered synchronous with the generating beam. To this end we have performed a numerical analysis by using the MAFIA simulation code, and have obtained, for a given geometry, the ampli- tude of the slowing down of the phase velocity due to the presence of the slot array. We have then performed a set of measurements of this e ect on a simple coaxial resonator, measuring the shift of the resonance frequencies produced by the slots. This shift, related to the phase velocity, has been compared with the results obtained with the simulations.

Slot-waveguide biochemical sensor.

Science.gov (United States)

Barrios, Carlos A; Gylfason, Kristinn B; Sánchez, Benito; Griol, Amadeu; Sohlström, H; Holgado, M; Casquel, R

2007-11-01

We report an experimental demonstration of an integrated biochemical sensor based on a slot-waveguide microring resonator. The microresonator is fabricated on a Si3N4-SiO2 platform and operates at a wavelength of 1.3 microm. The transmission spectrum of the sensor is measured with different ambient refractive indices ranging from n=1.33 to 1.42. A linear shift of the resonant wavelength with increasing ambient refractive index of 212 nm/refractive index units (RIU) is observed. The sensor detects a minimal refractive index variation of 2x10(-4) RIU.

Galvanic coupling effects for module-mounting elements of ground-mounted photovoltaic power station

Directory of Open Access Journals (Sweden)

Pierozynski Boguslaw

2017-12-01

Full Text Available This communication reports on the concerns associated with possible generation of galvanic coupling effects for construction materials that are used to manufacture mounting assemblies for ground-mounted photovoltaic (PV power stations. For this purpose, six macro-corrosion galvanic cells were assembled, including: hot-dip Zn/Magnelis®-coated steel/Al and stainless steel (SS/Al cells. Corrosion experiments involved continuous, ca. three-month exposure of these couplings in 3 wt.% NaCl solution, conducted at room temperature for a stable pH value of around 8. All corrosion cells were subjected to regular assessment of galvanic current-density and potential parameters, where special consideration was given to compare the corrosion behaviour of Zn-coated steel samples with that of Magnelis®-coated electrodes. Characterization of surface condition and elemental composition for examined materials was carried-out by means of SEM and EDX spectroscopy techniques.

Theoretical and experimental study of microstrip-to-slot line uniplanar transition

Science.gov (United States)

Yook, Jong-Gwan; Dib, Nihad I.; Katehi, Linda P. B.; Simons, Rainee N.; Taub, Susan R.

1994-05-01

Recent advances in MMCI technology make it possible to construct transitions from CPW-to-microstrip with via hole, microstrip-to-slot line and microshield line-to-CPW all of which have potential applications in the feed network of antennas. In this study we investigate the characteristics of the microstrip-to-slot line uniplanar transition using the finite element methods (FEM) and finite difference time domain (FDTD) techniques, and compared the theoretical results with the measurements. In both cases, the results agree with the measurements within a few percent.

Disc rotors with permanent magnets for brushless DC motor

Science.gov (United States)

Hawsey, Robert A.; Bailey, J. Milton

1992-01-01

A brushless dc permanent magnet motor drives an autonomous underwater vehe. In one embodiment, the motor comprises four substantially flat stators in stacked relationship, with pairs of the stators axially spaced, each of the stators comprising a tape-wound stator coil, and first and second substantially flat rotors disposed between the spaced pairs of stators. Each of the rotors includes an annular array of permanent magnets embedded therein. A first shaft is connected to the first rotor and a second, concentric shaft is connected to the second rotor, and a drive unit causes rotation of the two shafts in opposite directions. The second shaft comprises a hollow tube having a central bore in which the first shaft is disposed. Two different sets of bearings support the first and second shafts. In another embodiment, the motor comprises two ironless stators and pairs of rotors mounted on opposite sides of the stators and driven by counterrotating shafts.

Nonlinear theory of a cyclotron autoresonance maser (CARM) amplifier with outer-slotted-coaxial waveguide

International Nuclear Information System (INIS)

Qiu Chunrong; Ouyang Zhengbiao; Zhang Shichang; Zhang Huibo; Jin Jianbo; Lai Yingxin

2005-01-01

A self-consistent nonlinear theory for the outer-slotted-coaxial-waveguide cyclotron autoresonance maser (CARM) amplifier is presented, which includes the characteristic equation of the wave, coupling equation of the wave with the relativistic electron beam and the simulation model. The influences of the magnetic field, the slot depth and width are investigated. The interesting characteristic of the device is that the mode competition can be efficiently suppressed by slotting the outer wall of the coaxial waveguide. A typical example is given by the theoretical design of a 137 GHz outer-slotted-coaxial-waveguide CARM amplifier by utilizing an electron beam with a voltage of 90 kV, current of 50 A, velocity pitch angle of 0.85 and a magnetic field of 43.0 kG. The nonlinear simulation predicts a power of 467.9 kW, an electronic efficiency of 10.4% and a saturated gain of 46.7 dB, if the electron beam has no velocity spread. However, the axial velocity spread deteriorates the device; for example, if the axial velocity spread is 2%, the peak power decreases to 332.4 kW with an efficiency of 7.4% and a saturated gain of 45.22 dB. Simulation shows that the efficiency of the outer-slotted-coaxial-waveguide CARM amplifier may be increased from 10.4% to 29.6% by tapering the magnetic field

Dual-band reflective polarization converter based on slotted wire resonators

Science.gov (United States)

Li, Fengxia; Zhang, Linbo; Zhou, Peiheng; Chen, Haiyan; Zhao, Rui; Zhou, Yang; Liang, Difei; Lu, Haipeng; Deng, Longjiang

2018-02-01

A dual-band and high-efficiency reflective linear polarization converter composed of a layer of slotted metal wires has been proposed. Both the simulated and experimental results indicate that the structure can convert a linearly polarized wave to its cross-polarized state for two distinct frequency bands under normal incidence: 9.8-15.1 and 19.2-25.7 GHz. This phenomenon is attributed to a resonance that corresponds to the "trapped mode" at 15.8 GHz. This mode is stable with structural parameters and incident angle at a relatively wide range, and thus becomes promising for dual-band (also multiband) devices design. By surface current distribution and electric field analysis, the operation mechanism has been illuminated, especially for the "trapped mode", identified by the equally but also oppositely directed currents in each unit cell.

Airport slots and slot allocation: driver for mismatch between airline network and city needs? : the case of Rotterdam The Hague Airport

NARCIS (Netherlands)

van den Brandt, Marc; Mujica Mota, Miguel; Boosten, Geert; Hromádka, Martin

2014-01-01

Aviation increasingly faces capacity challenges exposing inefficiencies and shortcomings of aviation related processes and systems. The European slot allocation system was designed in an era with little to no capacity constraints, now resulting in regulations not fitting in today’s developments.

Numerical investigation of the LM MHD flows in a curved duct with an FCI with varying slot locations

International Nuclear Information System (INIS)

Yang, Jong Hoon; Yan, Yue; Kim, Chang Nyung

2016-01-01

Highlights: • This study numerically investigates the liquid-metal magnetohydrodynamic flows in a curved duct with an FCI. • The effects of the location of FCI slot and of the curvature radius on the flow behavior are reviewed. • The influence of the FCI slot position on the equalization of the pressure in the inner fluid region (inside the FCI) and the gap fluid region (outer the FCI) is examined. - Abstract: This study numerically investigates the liquid-metal (LM) magnetohydrodynamic (MHD) flows in a curved duct with an FCI having three different slot locations and having no slot under a uniform magnetic field perpendicular to the duct. The flow velocity, current density, electric potential, Lorentz force, and pressure in different flow situations are presented in detail. The effects of the location of FCI slot and of the curvature radius on the flow behavior are reviewed. The flow field is examined with an introduction of the electric-field component and electro-motive component of the current, allowing us to analyze the interdependency of the flow variables. The effect of the FCI slot position on the equalization of the pressure in the inner fluid region (inside the FCI) and the gap fluid region (outer the FCI) is examined. The result shows that and the case with an FCI slot located in the neutral position yields the smallest pressure gradient in the main flow direction among the cases with an FCI slot, resulting in the smallest pressure drop. Also, in a flow situation with smaller radius of curvature with the FCI slot in the neutral position, the axial velocity near the inner (in terms of the curvature) part of a cross-section is higher than that near the outer part.

Mounting arrangement for the drive system of an air-bearing spindle on a machine tool

Science.gov (United States)

Lunsford, J.S.; Crisp, D.W.; Petrowski, P.L.

1987-12-07

The present invention is directed to a mounting arrangement for the drive system of an air-bearing spindle utilized on a machine tool such as a lathe. The mounting arrangement of the present invention comprises a housing which is secured to the casing of the air bearing in such a manner that the housing position can be selectively adjusted to provide alignment of the air-bearing drive shaft supported by the housing and the air-bearing spindle. Once this alignment is achieved the air between spindle and the drive arrangement is maintained in permanent alignment so as to overcome misalignment problems encountered in the operation of the machine tool between the air-bearing spindle and the shaft utilized for driving the air-bearing spindle.

Driving and control strategies in alternative current machines of permanent magnet with non-sinusoidal flux; Estrategias de acionamento e controle em maquinas CA de ima permanente com fluxo nao senoidal

Energy Technology Data Exchange (ETDEWEB)

Monteiro, Jose Roberto Boffino de Almeida

1997-07-01

The aim of this work is to study and analyze the torque performance of brush less machines with non-sinusoidal distributed magnetic fluxes. The machine type considered is a surface mount permanent magnet brush less machine. Three mathematical models for the machine are considered: the per stator phase, the vectorial and the linear second order speed-voltage models. Machines with different stator windings are compared including the permanent magnet synchronous machines with sinusoidal distributed stator windings. The torque outputs of these machines are obtained considering two kinds of open loop driving systems: one with a six-pulse waveform and other with a sinusoidal waveform. Finally, a vectorial control is proposed for the non-sinusoidal machines. The torque ripple as well the overall performance of non-sinusoidal machines with vectorial control is compared to that of sinusoidal machines. (author)

Flush-mounting technique for composite beams

Science.gov (United States)

Harman, T. C.; Kay, B. F.

1980-01-01

Procedure permits mounting of heavy parts to surface of composite beams without appreciably weakening beam web. Web is split and held apart in region where attachment is to be made by lightweight precast foam filler. Bolt hole penetrates foam rather than web, and is secured by barrelnut in transverse bushing through web.

An efficient fringe integral equation method for optimizing the antenna location on complex bodies

DEFF Research Database (Denmark)

Jørgensen, Erik; Meincke, Peter; Breinbjerg, Olav

2001-01-01

The radiation pattern of an antenna mounted nearby, or directly on, a complex three-dimensional (3D) structure can be significantly influenced by this structure. Integral equations combined with the method of moments (MoM) provide an accurate means for calculating the scattering from the structures...... in such applications. The structure is then modelled by triangular or rectangular surface patches with corresponding surface current expansion functions. A MoM matrix which is independent of the antenna location can be obtained by modelling the antenna as an impressed electric or magnetic source, e.g., a slot antenna...... can be modelled by a magnetic Hertzian dipole. For flush-mounted antennas, or antennas mounted in close vicinity of the scattering structure, the nearby impressed source induces a highly peaked surface current on the scattering structure. For the low-order basis functions usually applied...

Mounting system for optical frequency reference cavities

Science.gov (United States)

Notcutt, Mark (Inventor); Hall, John L. (Inventor); Ma, Long-Sheng (Inventor)

2008-01-01

A technique for reducing the vibration sensitivity of laser-stabilizing optical reference cavities is based upon an improved design and mounting method for the cavity, wherein the cavity is mounted vertically. It is suspended at one plane, around the spacer cylinder, equidistant from the mirror ends of the cavity. The suspension element is a collar of an extremely low thermal expansion coefficient material, which surrounds the spacer cylinder and contacts it uniformly. Once the collar has been properly located, it is cemented in place so that the spacer cylinder is uniformly supported and does not have to be squeezed at all. The collar also includes a number of cavities partially bored into its lower flat surface, around the axial bore. These cavities are support points, into which mounting base pins will be inserted. Hence the collar is supported at a minimum of three points.

A Novel Cogging Torque Simulation Method for Permanent-Magnet Synchronous Machines

Directory of Open Access Journals (Sweden)

Chun-Yu Hsiao

2011-12-01

Full Text Available Cogging torque exists between rotor mounted permanent magnets and stator teeth due to magnetic attraction and this is an undesired phenomenon which produces output ripple, vibration and noise in machines. The purpose of this paper is to study the existence and effects of cogging torque, and to present a novel, rapid, half magnet pole pair technique for forecasting and evaluating cogging torque. The technique uses the finite element method as well as Matlab research and development oriented software tools to reduce numerous computing jobs and simulation time. An example of a rotor-skewed structure used to reduce cogging torque of permanent magnet synchronous machines is evaluated and compared with a conventional analysis method for the same motor to verify the effectiveness of the proposed approach. The novel method is proved valuable and suitable for large-capacity machine design.

Numerical exploration of non-axisymmetric divertor closure in the small angle slot (SAS) divertor at DIII-D

Science.gov (United States)

Frerichs, H.; Schmitz, O.; Covele, B.; Feng, Y.; Guo, H. Y.; Hill, D.

2018-05-01

Numerical simulations of toroidal asymmetries in a tightly baffled small angle slot (SAS) divertor on the DIII-D tokamak show that toroidal asymmetries in divertor closure result in (non-axisymmetric) local onset of detachment within a density window of 10-15% on top of the nominal threshold separatrix density. The SAS divertor is explored at DIII-D for improving access to cold, dissipative/detached divertor conditions. The narrow width of the slot divertor coupled with a small magnetic field line-to-target angle facilitates the buildup of neutral density, thereby increasing radiative and neutrals-related (atoms and molecules) losses in the divertor. Small changes in the strike point location can be expected to have a large impact on divertor conditions. The combination of misaligned slot structure and non-axisymmetric perturbations to the magnetic field configuration causes the strike point to move along the divertor target plate, possibly leaving the divertor slot at some locations. The latter extreme case essentially introduces an opening in the divertor slot from where recycling neutrals can easily escape, and thereby degrade the performance of the slot divertor. Such a strike point dislocation is approximated by a finite gap in the divertor baffle for which 3D edge plasma and neutral gas simulations are performed with the EMC3-EIRENE code.

Tuning ZOR in ENZ waveguide using a single longitudinal slot and equivalent circuit parameter extraction

DEFF Research Database (Denmark)

Vojnovic, Nebojsa; Jokanovic, Branka; Mitrovic, Miranda

2014-01-01

In this paper, the effects of placing a longitudinal slot in the channel region of a rectangular waveguide ENZ structure, are analyzed. A following investigation showed that changing the length of this slot can be employed to achieve tuning of only the tunneling frequency. Maximum resonant freque...

Measurement & Minimization of Mount Induced Strain on Double Crystal Monochromator Crystals

Science.gov (United States)

Kelly, J.; Alcock, S. G.

2013-03-01

Opto-mechanical mounts can cause significant distortions to monochromator crystals and mirrors if not designed or implemented carefully. A slope measuring profiler, the Diamond-NOM [1], was used to measure the change in tangential slope as a function of crystal clamping configuration and load. A three point mount was found to exhibit the lowest surface distortion (Diamond Light Source.

Magnetically induced rotor vibration in dual-stator permanent magnet motors

Science.gov (United States)

Xie, Bang; Wang, Shiyu; Wang, Yaoyao; Zhao, Zhifu; Xiu, Jie

2015-07-01

Magnetically induced vibration is a major concern in permanent magnet (PM) motors, which is especially true for dual-stator motors. This work develops a two-dimensional model of the rotor by using energy method, and employs this model to examine the rigid- and elastic-body vibrations induced by the inner stator tooth passage force and that by the outer. The analytical results imply that there exist three typical vibration modes. Their presence or absence depends on the combination of magnet/slot, force's frequency and amplitude, the relative position between two stators, and other structural parameters. The combination and relative position affect these modes via altering the force phase. The predicted results are verified by magnetic force wave analysis by finite element method (FEM) and comparison with the existing results. Potential directions are also given with the anticipation of bringing forth more interesting and useful findings. As an engineering application, the magnetically induced vibration can be first reduced via the combination and then a suitable relative position.

Output Feedback Adaptive Dynamic Surface Control of Permanent Magnet Synchronous Motor with Uncertain Time Delays via RBFNN

Directory of Open Access Journals (Sweden)

Shaohua Luo

2014-01-01

Full Text Available This paper focuses on an adaptive dynamic surface control based on the Radial Basis Function Neural Network for a fourth-order permanent magnet synchronous motor system wherein the unknown parameters, disturbances, chaos, and uncertain time delays are presented. Neural Network systems are used to approximate the nonlinearities and an adaptive law is employed to estimate accurate parameters. Then, a simple and effective controller has been obtained by introducing dynamic surface control technique on the basis of first-order filters. Asymptotically tracking stability in the sense of uniformly ultimate boundedness is achieved in a short time. Finally, the performance of the proposed control has been illustrated through simulation results.

Dynamic Allocation of SPM Based on Time-Slotted Cache Conflict Graph for System Optimization

Science.gov (United States)

Wu, Jianping; Ling, Ming; Zhang, Yang; Mei, Chen; Wang, Huan

This paper proposes a novel dynamic Scratch-pad Memory allocation strategy to optimize the energy consumption of the memory sub-system. Firstly, the whole program execution process is sliced into several time slots according to the temporal dimension; thereafter, a Time-Slotted Cache Conflict Graph (TSCCG) is introduced to model the behavior of Data Cache (D-Cache) conflicts within each time slot. Then, Integer Nonlinear Programming (INP) is implemented, which can avoid time-consuming linearization process, to select the most profitable data pages. Virtual Memory System (VMS) is adopted to remap those data pages, which will cause severe Cache conflicts within a time slot, to SPM. In order to minimize the swapping overhead of dynamic SPM allocation, a novel SPM controller with a tightly coupled DMA is introduced to issue the swapping operations without CPU's intervention. Last but not the least, this paper discusses the fluctuation of system energy profit based on different MMU page size as well as the Time Slot duration quantitatively. According to our design space exploration, the proposed method can optimize all of the data segments, including global data, heap and stack data in general, and reduce the total energy consumption by 27.28% on average, up to 55.22% with a marginal performance promotion. And comparing to the conventional static CCG (Cache Conflicts Graph), our approach can obtain 24.7% energy profit on average, up to 30.5% with a sight boost in performance.

Compact broadband circularly polarised slot antenna for universal UHF RFID readers

DEFF Research Database (Denmark)

Xu, Bo; Zhang, Shuai; Liu, Yusha

2015-01-01

A compact broadband circularly polarised (CP) slot antenna is designed for universal ultra-high-frequency (UHF) radio frequency identification (RFID) readers. The antenna consists of an L-shaped metal strip and a square-slot-loaded ground plane with four tuning stubs. The total size is 100 mm×100mm......×1.6 mm. The measured –10 dB impedance bandwidth is 40.7% (772–1166 MHz) and the measured 3 dB axial ratio (AR) bandwidth is 13.9% (840–965 MHz). Both the impedance and AR bandwidth cover the worldwide UHF RFID band....

Electromagnetically induced transparency and ultraslow optical solitons in a coherent atomic gas filled in a slot waveguide.

Science.gov (United States)

Xu, Jin; Huang, Guoxiang

2013-02-25

We investigate the electromagnetically induced transparency (EIT) and nonlinear pulse propagation in a Λ-type three-level atomic gas filled in a slot waveguide, in which electric field is strongly confined inside the slot of the waveguide due to the discontinuity of dielectric constant. We find that EIT effect can be greatly enhanced due to the reduction of optical-field mode volume contributed by waveguide geometry. Comparing with the atomic gases in free space, the EIT transparency window in the slot waveguide system can be much wider and deeper, and the Kerr nonlinearity of probe laser field can be much stronger. We also prove that using slot waveguide ultraslow optical solitons can be produced efficiently with extremely low generation power.

COMPARATIVE EFFICIENCIES STUDY OF SLOT MODEL AND MOUSE MODEL IN PRESSURISED PIPE FLOW

Directory of Open Access Journals (Sweden)

Saroj K. Pandit

2014-01-01

Full Text Available The flow in sewers is unsteady and variable between free-surfac e to full pipe pressurized flow. Sewers are designed on the basis of free surf ace flow (gravity flow however they may carry pressurized flow. Preissmann Slot concep t is widely used numerical approach in unsteady free surface-pressurized flow as it provides the advantage of using free surface flow as a single type flow. Slo t concept uses the Saint- Venant’s equations as a basic equation for one-dimensional unst eady free surface flow. This paper includes two different numerical models using Saint Venant’s equations. The Saint Venant’s e quations of continuity and momen tum are solved by the Method of Characteristics and presented in forms for direct substitution into FORTRAN programming for numerical analysis in the first model. The MOUSE model carries out computation of unsteady flows which is founde d on an implicit, finite difference numerical solut ion of the basic one dimension al Saint Venant’s equations of free surface flow. The simulation results are comp ared to analyze the nature and degree of errors for further improvement.

Permanent magnet machines with air gap windings and integrated teeth windings

Energy Technology Data Exchange (ETDEWEB)

Alatalo, M [Chalmers Univ. of Technology, Goeteborg (Sweden). School of Electrical and Computer Engineering

1996-06-01

The Thesis deals with axial and radial flux permanent magnet machines with air gap windings and an integrated teeth winding. The aim is to develop a machine that produces a high torque per unit volume with as low losses as possible. The hypothesis is that an advanced three-phase winding, magnetized by a permanent magnet rotor should be better than other machine topologies. The finite element method is used to find favourable dimensions of the slotless winding, the integrated teeth winding and the permanent magnet rotor. Three machines were built and tested in order to verify calculations. It can be concluded that the analysis method shows good agreement with the calculated and the measured values of induced voltage and torque. The experiments showed that the slotless machine with NdFeB-magnets performs approximately like the slotted machine. A theoretical comparison of axial flux topology to radial flux topology showed that the torque production of the inner rotor radial flux machine is superior to that of the axial flux machine. An integrated teeth winding based on iron powder teeth glued to the winding was studied. The force density of a pole with integrated teeth is around three times the force density of a slotless pole. A direct drive wind power generator of 6.4 kW with integrated teeth can have the same power losses and magnet weight as a transversal flux machine. Compared to a standard induction machine the integrated teeth machine had approximately 2.5 times the power capacity of the induction machine with the same power losses and outer volume. 39 refs

Slot Machine Response Frequency Predicts Pathological Gambling

DEFF Research Database (Denmark)

Linnet, Jakob; Rømer Thomsen, Kristine; Møller, Arne

2013-01-01

. This study tested the hypothesis that response frequency is associated with symptom severity in pathological gambling. We tested response frequency among twenty-two pathological gambling sufferers and twenty-one non-problem gamblers on a commercially available slot machine, and screened for pathological...... in individuals with exacerbated pathological gambling symptoms. These findings may have important implications for detecting behaviors underlying pathological gambling....

Fixture For Mounting A Pressure Sensor

Science.gov (United States)

Cagle, Christopher M.

1995-01-01

Fixture for mounting pressure sensor in aerodynamic model simplifies task of removal and replacement of sensor in event sensor becomes damaged. Makes it unnecessary to dismantle model. Also minimizes any change in aerodynamic characteristics of model in event of replacement. Removable pressure sensor installed in fixture in wall of model. Wires from sensor pass through channel under surface.

Quasi-plane-hypothesis of strain coordination for RC beams seismically strengthened with externally-bonded or near-surface mounted fiber reinforced plastic

Science.gov (United States)

Ren, Zhenhua; Zeng, Xiantao; Liu, Hanlong; Zhou, Fengjun

2013-03-01

The application of fiber reinforced plastic (FRP), including carbon FRP and glass FRP, for structural repair and strengthening has grown due to their numerous advantages over conventional materials such as externally bonded reinforcement (EBR) and near-surface mounted (NSM) strengthening techniques. This paper summarizes the results from 21 reinforced concrete beams strengthened with different methods, including externally-bonded and near-surface mounted FRP, to study the strain coordination of the FRP and steel rebar of the RC beam. Since there is relative slipping between the RC beam and the FRP, the strain of the FRP and steel rebar of the RC beam satisfy the quasi-plane-hypothesis; that is, the strain of the longitudinal fiber that parallels the neutral axis of the plated beam within the scope of the effective height ( h 0) of the cross section is in direct proportion to the distance from the fiber to the neutral axis. The strain of the FRP and steel rebar satisfies the equation: ɛ FRP= βɛ steel, and the value of β is equal to 1.1-1.3 according to the test results.

Modeling arbitrarily directed slots that are narrow both in width and depth with regard to the FDTD spatial cell. [Finite Difference-Time Domain (TDTD)

Energy Technology Data Exchange (ETDEWEB)

Riley, D.J.; Turner, C.D.

1991-01-01

The Hybrid Thin-Slot Algorithm (HTSA) integrates a transient integral-equation solution for an aperture in an infinite plane into a finite-difference time-domain (FDTD) code. The technique was introduced for linear apertures and was extended to include wall loss and lossy internal gaskets. A general implementation for arbitrary thin slots is briefly described here. The 3-D FDTD-code TSAR was selected for the implementation. The HTSA does not provide universal solutions to the narrow slot problem, but has merits appropriate for particular applications. The HTSA is restricted to planar slots, but can solve the important case that both the width and depth of the slot are narrow compared to the FDTD spatial cell. IN addition, the HTSA is not bound to the FDTD discrete spatial and time increments, and therefore, high-resolution solutions for the slot physics are possible. The implementation of the HTSA into TSAR is based upon a slot data file'' that includes the cell indices where the desired slots are exist within the FDTD mesh. For an HTSA-defined slot, the wall region local to the slot is shorted, and therefore, to change the slot's topology simply requires altering the file to include the desired cells. 7 refs.

Three-dimensional hard and soft tissue imaging of the human cochlea by scanning laser optical tomography (SLOT.

Directory of Open Access Journals (Sweden)

Nadine Tinne

Full Text Available The present study focuses on the application of scanning laser optical tomography (SLOT for visualization of anatomical structures inside the human cochlea ex vivo. SLOT is a laser-based highly efficient microscopy technique which allows for tomographic imaging of the internal structure of transparent specimens. Thus, in the field of otology this technique is best convenient for an ex vivo study of the inner ear anatomy. For this purpose, the preparation before imaging comprises decalcification, dehydration as well as optical clearing of the cochlea samples in toto. Here, we demonstrate results of SLOT imaging visualizing hard and soft tissue structures with an optical resolution of down to 15 μm using extinction and autofluorescence as contrast mechanisms. Furthermore, the internal structure can be analyzed nondestructively and quantitatively in detail by sectioning of the three-dimensional datasets. The method of X-ray Micro Computed Tomography (μCT has been previously applied to explanted cochlea and is solely based on absorption contrast. An advantage of SLOT is that it uses visible light for image formation and thus provides a variety of contrast mechanisms known from other light microscopy techniques, such as fluorescence or scattering. We show that SLOT data is consistent with μCT anatomical data and provides additional information by using fluorescence. We demonstrate that SLOT is applicable for cochlea with metallic cochlear implants (CI that would lead to significant artifacts in μCT imaging. In conclusion, the present study demonstrates the capability of SLOT for resolution visualization of cleared human cochleae ex vivo using multiple contrast mechanisms and lays the foundation for a broad variety of additional studies.

Research on TIG weld machine of the upper side ring slot of Gd-rod technology reconstruct

International Nuclear Information System (INIS)

Fang Shixiang; Lan Zhibing; Cui Quhu

2010-01-01

The research on TIG weld machine of the upper side ring slot of Gd-rod existent matter: seal electrical source got up difficulty; control system had graveness aging; space between was adjusted precision lowness; welding torch lay mode and structure were not in reason. carried through all around technology reconstruct: had chosen the best of TIG weld machine; designed ignite arc device, designed optics imaging device, designed tungsten mighty axis direction auto conditioning, was provided with arc slot, adopted PLC to control the whole system and realization auto control. After TIG weld machine of the upper side ring slot of Gd-rod technology reconstruct research , provided with arc slot the first time in the Gd-rod of nuclear fuel, optimized the weld technics, improved welding line melt width and deep equality, stability, and great breadth advanced nuclear fuel product line technology and throughput. (authors)

Study of Allocation Guaranteed Time Slot Wireless Body Area Networks Based on IEEE 802.15.4

Science.gov (United States)

Yundra, E.; Harsono, G. D.

2018-04-01

This paper aims to determine the size of the Guaranteed Time Slot (GTS) on the super frame structure required for each sensor as well as to know the performance of the GTS resized system compared to the GTS standard on IEEE 802.15.4. This article proposes a scheme to improve IEEE 802.15.4 medium access control, called allocation Guaranteed Time Slot (ALGATIS). ALGATIS is expected to effectively allocate guaranteed time slot to the requested sensors, it adjusts the length of the slot in super frame duration based on the length of the packet data. This article presents a simulation experiment of IEEE 802.15.4, especially for star network, to predict the throughput of networks and average energy consumption. The simulation experiments show that the performance of ALGATIS is better than that of IEEE 802.15.4 standard in term of the throughput of networks and average energy consumption

Magnetic core mounting system

Science.gov (United States)

Ronning, Jeffrey J.

2002-01-01

A mounting apparatus for an electromagnetic device such as a transformer of inductor includes a generally planar metallic plate as a first heat sink, and a metallic mounting cup as a second heat sink. The mounting cup includes a cavity configured to receive the electromagnetic device, the cavity being defined by a base, and an axially-extending annular sidewall extending from the base to a flange portion of the mounting cup. The mounting cup includes first and second passages for allowing the leads of first and second windings of the electromagnetic device to be routed out of the cavity. The cavity is filled with a polyurethane potting resin, and the mounting cup, including the potted electromagnetic device, is mounted to the plate heat sink using fasteners. The mounting cup, which surrounds the electromagnetic device, in combination with the potting resin provides improved thermal transfer to the plate heat sink, as well as providing resistance to vibration and shocks.

Landscape Response to the 1980 Eruption of Mount St. Helens: Using Historical Aerial Photography to Measure Surface Change

Science.gov (United States)

Sweeney, K.; Major, J. J.

2016-12-01

Advances in structure-from-motion (SfM) photogrammetry and point cloud comparison have fueled a proliferation of studies using modern imagery to monitor geomorphic change. These techniques also have obvious applications for reconstructing historical landscapes from vertical aerial imagery, but known challenges include insufficient photo overlap, systematic "doming" induced by photo-spacing regularity, missing metadata, and lack of ground control. Aerial imagery of landscape change in the North Fork Toutle River (NFTR) following the 1980 eruption of Mount St. Helens is a prime dataset to refine methodologies. In particular, (1) 14-μm film scans are available for 1:9600 images at 4-month intervals from 1980 - 1986, (2) the large magnitude of landscape change swamps systematic error and noise, and (3) stable areas (primary deposit features, roads, etc.) provide targets for both ground control and matching to modern lidar. Using AgiSoft PhotoScan, we create digital surface models from the NFTR imagery and examine how common steps in SfM workflows affect results. Tests of scan quality show high-resolution, professional film scans are superior to office scans of paper prints, reducing spurious points related to scan infidelity and image damage. We confirm earlier findings that cropping and rotating images improves point matching and the final surface model produced by the SfM algorithm. We demonstrate how the iterative closest point algorithm, implemented in CloudCompare and using modern lidar as a reference dataset, can serve as an adequate substitute for absolute ground control. Elevation difference maps derived from our surface models of Mount St. Helens show patterns consistent with field observations, including channel avulsion and migration, though systematic errors remain. We suggest that subtracting an empirical function fit to the long-wavelength topographic signal may be one avenue for correcting systematic error in similar datasets.

Multiband Slot-Based Dual Composite Right/Left-Handed Transmission Line

Directory of Open Access Journals (Sweden)

E. Abdo-Sanchez

2012-10-01

Full Text Available A dual Composite Right-/Left-Handed Transmission Line (CRLH TL implementation that presents multiband behaviour is proposed in this contribution. The artificial TL is realized by loading a host microstrip line with alternate rectangular stubs and slots. The required series and shunt immittances are respectively provided by the slot and the stub. Due to the distributed nature of these immittances, the resultant phase response presents theoretically infinite RH and LH alternate bands, thus being appropriate for multiband applications. The design methodology is described with the help of a proposed TLs-based equivalent circuit and highlights the simplicity for balance condition. Full wave simulated results of the dispersion characteristics and frequency response of a unit-cell and a three-cells structure are presented.

Studies on diversion cross-flow between two parallel channels communicating by a lateral slot. II

International Nuclear Information System (INIS)

Tapucu, A.; Merilo, M.

1977-01-01

The axial pressure variations of two parallel channels with single phase flows communicating by a long lateral slot have been studied experimentally. Using mass and momentum conservation principles, the axial pressure variations have been derived in terms of two parameters ksub(d) and ksub(r), for donor and recipient channels, respectively. These parameters include the combined effect of fluid transferred from donor to recipient channel, and drag force brought on by the connection gap, and are functions of the velocities and slot geometry parameters. A pressure difference oscillation between channels along the slot has been detected which is sinusoidal with wave lengths which seem to be a function of the gap clearance. (Auth.)

[Does the mounting of gastrointestinal biopsies on millipore filter contribute to an improved section quality?

DEFF Research Database (Denmark)

Asmussen, L.; Bernstein, I.; Matzen, P.

2009-01-01

orientation, GIB is occasionally mounted on millipore filter (MF) in an attempt to place the deep cut side onto the MF. The importance of this technique for section quality is evaluated in this study. MATERIAL AND METHOD: The material comprised three consecutive series of GIB (60 gastric, duodenal......, and colorectal GIB, respectively). Sections were grouped in MF-mounted versus non-mounted GIB, the proportion of fully acceptable sections among mounted versus non-mounted GIB was recorded. RESULTS: 77.2% of all GIBs were MF-mounted. 33.1% of mounted GIBs versus 48.8% of non-mounted GIBs were assessed as fully...... acceptable sections. The differences between these figures are not statistically significant. 41.7% of the mounted GIBs were placed with the mucosal surface facing the MF, which entails a risk of damaging the tissue. CONCLUSION: MF-mounting of GIB did not contribute to section quality. Since the handling...

Turbulent flow and heat transfer from a slot jet impinging on a moving plate

International Nuclear Information System (INIS)

Chattopadhyay, Himadri; Saha, Sujoy K.

2003-01-01

The flow field due to an impinging jet over a moving surface at a moderately high Reynolds number, emanating from a rectangular slot nozzle has been computed using the large eddy simulation technique. A dynamic subgrid-scale stress model has been used for the small scales of turbulence. The velocity of the impinging surface perpendicular to the jet velocity has been varied up to two times the jet velocity at the nozzle exit. Turbulence quantities such as kinetic energy, production rate of turbulent kinetic energy and the Reynolds stresses are calculated for different surface velocities. It has been observed that, while the turbulent kinetic energy increases with increasing velocity of the impinging surface, production rate of turbulence initially increases with increasing surface velocity and then comes down. By analyzing the components of turbulent production it was found that P 33 is the dominant term up to the surface velocity of one unit and when the surface velocity is two times the jet velocity at the nozzle exit, the major contribution to turbulence production comes from P 13 and partly from P 11 . Heat transfer from the plate initially increases with non-dimensional surface velocity up to 1.2 and then comes down

Design and analysis of new fault-tolerant permanent magnet motors for four-wheel-driving electric vehicles

Science.gov (United States)

Liu, Guohai; Gong, Wensheng; Chen, Qian; Jian, Linni; Shen, Yue; Zhao, Wenxiang

2012-04-01

In this paper, a novel in-wheel permanent-magnet (PM) motor for four-wheel-driving electrical vehicles is proposed. It adopts an outer-rotor topology, which can help generate a large drive torque, in order to achieve prominent dynamic performance of the vehicle. Moreover, by adopting single-layer concentrated-windings, fault-tolerant teeth, and the optimal combination of slot and pole numbers, the proposed motor inherently offers negligible electromagnetic coupling between different phase windings, hence, it possesses a fault-tolerant characteristic. Meanwhile, the phase back electromotive force waveforms can be designed to be sinusoidal by employing PMs with a trapezoidal shape, eccentric armature teeth, and unequal tooth widths. The electromagnetic performance is comprehensively investigated and the optimal design is conducted by using the finite-element method.

Low-stress mounting configuration design for large aperture laser transport mirror

Science.gov (United States)

Zhang, Zheng; Quan, Xusong; Yao, Chao; Wang, Hui

2016-10-01

TM1-6S1 large aperture laser transport mirror is a crucial optical unit of high power solid-state laser in the Inertial Confinement Fusion (ICF) facility. This article focuses on the low-stress and precise mounting method of large-aperture mirror. Based on the engineering practice of SG-III, the state-of-the-art and key problems of current mounting configuration are clarified firstly. Subsequently, a brand new low-stress mounting configuration with flexure supports is proposed. Opto-mechanical model of the mirror under mounting force is built up with elastic mechanics theory. Further, numerical methods and field tests are employed to verify the favorable load uniform capacity and load adjust capacity of flexure supports. With FEM, the relation between the mounting force from new configuration and the mirror surface distortion (wavefront error) is clarified. The novel mounting method of large aperture optics could be not only used on this laser transport mirror, but also on the other transmission optics and large crystals in ICF facilities.

Band structures in two-dimensional phononic crystals with periodic Jerusalem cross slot

Science.gov (United States)

Li, Yinggang; Chen, Tianning; Wang, Xiaopeng; Yu, Kunpeng; Song, Ruifang

2015-01-01

In this paper, a novel two-dimensional phononic crystal composed of periodic Jerusalem cross slot in air matrix with a square lattice is presented. The dispersion relations and the transmission coefficient spectra are calculated by using the finite element method based on the Bloch theorem. The formation mechanisms of the band gaps are analyzed based on the acoustic mode analysis. Numerical results show that the proposed phononic crystal structure can yield large band gaps in the low-frequency range. The formation mechanism of opening the acoustic band gaps is mainly attributed to the resonance modes of the cavities inside the Jerusalem cross slot structure. Furthermore, the effects of the geometrical parameters on the band gaps are further explored numerically. Results show that the band gaps can be modulated in an extremely large frequency range by the geometry parameters such as the slot length and width. These properties of acoustic waves in the proposed phononic crystals can potentially be applied to optimize band gaps and generate low-frequency filters and waveguides.

Numerical exploration of non-axisymmetric divertor closure in the small angle slot (SAS) divertor at DIII-D

Science.gov (United States)

Frerichs, Heinke; Schmitz, Oliver; Covele, Brent; Guo, Houyang; Hill, David; Feng, Yuhe

2017-10-01

In the Small Angle Slot (SAS) divertor in DIII-D, the combination of misaligned slot structure and non-axisymmetric perturbations to the magnetic field causes the strike point to vary radially along the divertor slot and even leave it at some toroidal locations. This effect essentially introduces an opening in the divertor slot from where recycling neutrals can easily escape, and thereby degrade performance of the slot divertor. This effect has been approximated by a finite gap in the divertor baffle. Simulations with EMC3-EIRENE show that a toroidally localized loss of divertor closure can result in non-axisymmetric divertor densities and temperatures. This introduces a density window of 10-15% on top of the nominal threshold separatrix density during which a non-axisymmetric onset of local detachment occurs, initially leaving the gap and up to 60 deg beyond that still attached. Conversely, the impact of such toroidally localized divertor perturbations on the toroidal symmetry of midplane separatrix conditions is small. This work has been funded by the U.S. Department of Energy under Early Career Award Grant DE-SC0013911, and Grant DE-FC02-04ER54698.

Dark Flow, Depression and Multiline Slot Machine Play.

Science.gov (United States)

Dixon, Mike J; Stange, Madison; Larche, Chanel J; Graydon, Candice; Fugelsang, Jonathan A; Harrigan, Kevin A

2018-03-01

Multiline slot machines allow for a unique outcome type referred to as a loss disguised as a win (LDW). An LDW occurs when a player gains credits on a spin, but fewer credits than their original wager (e.g. 15-cent gain on a 20-cent wager). These outcomes alter the gambler's play experience by providing frequent, albeit smaller, credit gains throughout a playing session that are in fact net losses. Despite this negative overall value, research has shown that players physiologically respond to LDWs as if they are wins, not losses. These outcomes also create a "smoother" experience for the player that seems to promote a highly absorbing, flow-like state that we have called "dark flow". Past research has indicated that there may be a relationship between problem gambling status and dark flow, as well as between dark flow, depression, and gambling expectancies. In this study, we sought to further understand these relationships, while examining the influence of LDWs on game preference in the context of single versus multiline slots play. We used a realistic slot machine simulator equipped with a force transducer to measure how hard players pressed the spin button following different outcomes. This measure of arousal showed that LDWs were treated similarly to small wins. Participants overwhelmingly preferred the multiline game and experienced more positive affect while playing it, compared to the single-line game. Problem gambling severity index scores were related to dark flow in both games, but this relationship was stronger for the multiline game. Additionally, depression symptomatology and dark flow were strongly correlated in the multiline game, with significant relationships between depression and gambling expectancy, and gambling expectancy and dark flow ratings also emerging.

Gravity and magma induces spreading of Mount Etna volcano revealed by satellite radar interferometry

Science.gov (United States)

Lungren, P.; Casu, F.; Manzo, M.; Pepe, A.; Berardino, P.; Sansosti, E.; Lanari, R.

2004-01-01

Mount Etna underwent a cycle of eruptive activity over the past ten years. Here we compute ground displacement maps and deformation time series from more than 400 radar interferograms to reveal Mount Etna's average and time varying surface deformation from 1992 to 2001.

Wave Pressures on Seawave Slot-Cone Generator

DEFF Research Database (Denmark)

Vicinanza, Diego; Kofoed, Jens Peter; Frigaard, Peter

2006-01-01

This paper presents results on loading action on an innovative caisson breakwater for electricity production. The work reported here contributes to the European Union Sixth Framework programme priority 6.1 (Sustainable Energy System), contract 019831, titled "Full- scale demonstration of robust...... and high efficiency energy converter" (WAVESSG). Information on wave loading acting on Wave Energy Convert (WEC) Seawave Slot-Cone GEnerator (SSG) exposed to extreme wave conditions are reported....

Measurement of fatigue crack growth using low-profile eddy-current sensors

International Nuclear Information System (INIS)

Ditchburn, R.J.; Ibrahim, M.E.; Burke, S.K.

2011-01-01

Conformable spiral coils show promise as permanently mounted eddy-current sensors for the detection and monitoring of surface-breaking cracks in electrically conductive structures. Flexibility and a low profile (typically less than 0.5 mm) are key advantages that allow the sensors to be unobtrusively mounted on curved surfaces and beneath surface coatings. Furthermore, these sensors can be permanently mounted in areas that would otherwise be difficult or impossible to reach without significant disassembly. The sensors can be activated and interrogated using the same well-established electromagnetic measurement principles in eddy-current nondestructive inspection. A material test machine was used to grow through-thickness fatigue crack in a compact-tension specimen made from the aerospace-grade aluminium alloy AA2014. The growth of the crack was examined by measuring the small impedance changes of planar spiral-coil sensors attached to the specimen. The results indicate that permanently attached conformable spiral coils can be used to detect a deep crack once it has grown beneath the sensor, and then to monitor subsequent crack growth.

Fourier method for modeling slanted lamellar gratings of arbitrary end-surface shapes in conical mounting.

Science.gov (United States)

Li, Lifeng

2015-10-01

An efficient modal method for numerically modeling slanted lamellar gratings of isotropic dielectric or metallic media in conical mounting is presented. No restrictions are imposed on the slant angle and the length of the lamellae. The end surface of the lamellae can be arbitrary, subject to certain restrictions. An oblique coordinate system that is adapted to the slanted lamella sidewalls allows the most efficient way of representing and manipulating the electromagnetic fields. A translational coordinate system that is based on the oblique Cartesian coordinate system adapts to the end-surface profile of the lamellae, so that the latter can be handled simply and easily. Moreover, two matrix eigenvalue problems of size 2N × 2N, one for each fundamental polarization of the electromagnetic fields in the periodic lamellar structure, where N is the matrix truncation number, are derived to replace the 4N × 4N eigenvalue problem that has been used in the literature. The core idea leading to this success is the polarization decomposition of the electromagnetic fields inside the periodic lamellar region when the fields are expressed in the oblique translational coordinate system.

Liner mounting assembly

Science.gov (United States)

Halila, Ely E. (Inventor)

1994-01-01

A mounting assembly includes an annular supporting flange disposed coaxially about a centerline axis which has a plurality of circumferentially spaced apart supporting holes therethrough. An annular liner is disposed coaxially with the supporting flange and includes a plurality of circumferentially spaced apart mounting holes aligned with respective ones of the supporting holes. Each of a plurality of mounting pins includes a proximal end fixedly joined to the supporting flange through a respective one of the supporting holes, and a distal end disposed through a respective one of the liner mounting holes for supporting the liner to the supporting flange while unrestrained differential thermal movement of the liner relative to the supporting flange.

Probabilistic Dynamic Framed Slotted ALOHA for RFID Tag Identification

DEFF Research Database (Denmark)

Nguyen, Chuyen T.; Hayashi, Kazunori; Kaneko, Megumi

2013-01-01

In this paper, we study radio frequency identification tag identification problems using framed slotted ALOHA protocol. Each tag will be assumed to participate in the contention with a certain probability. Then, the frame size and the probability will be dynamically controlled by the reader in ev...

A High Torque Segmented Outer Rotor Permanent Magnet Flux Switching Motor for Motorcycle Propulsion

Directory of Open Access Journals (Sweden)

Mbadiwe I Enwelum

2018-01-01

Full Text Available Electric scooters also known as electric motorcycle are viable and personal means of road transportation have been making their ways into the world markets now because in them, combustion engine with the use of fuel oil for propulsion have been completely eliminated for economic and environmental imperatives. Electric motor which converts electrical energy into mechanical energy is used to overcome the complication of combustion engine. As it is, everyone is opting for combustion engine free and fuel-less type of vehicle. For this reason, manufacturers have exhibited interest, making research on electric motor very attractive. Meanwhile, surface permanent magnet synchronous motor (SPMSM has been successfully developed having output torque of 110 Nm, the assembly of motor lacked mechanical strength between the rotor yoke and the mounted permanent magnet (PM which heats up during speed operation, resulting to poor performance. To overcome the challenges laced with SPMSM, this paper presents a novel design of 24 stator 14 pole outer rotor-permanent magnet flux switching motor (SOR-PMFSM capable of high torque and high performance. It employs an unconventional segmented rotor which has short flux path flow. It also embraces alternate stator tooth windings to reduce material cost. Design specifications and restriction with input DC current are the same with SPMSM. The 2D-FEA by JMAG, version 14 is used to examine the performance of the proposed motor in terms of cogging torque, back-emf, average torque, power and efficiency. Preliminary results showed that torque, power output and efficiency of the proposed motor are 1.9Nm times, 5.8kW times more than SPMSM and efficiency of 84% thus, can sustain acceleration for long distance travel.

Immunocytochemical investigation of immune cells within human primary and permanent tooth pulp.

Science.gov (United States)

Rodd, H D; Boissonade, F M

2006-01-01

The aim of this study was to determine whether there are any differences in the number and distribution of immune cells within human primary and permanent tooth pulp, both in health and disease. The research took the form of a quantitative immunocytochemical study. One hundred and twenty-four mandibular first permanent molars and second primary molars were obtained from children requiring dental extractions under general anaesthesia. Following exodontia, 10-microm-thick frozen pulp sections were processed for indirect immunofluorescence. Triple-labelling regimes were employed using combinations of the following: (1) protein gene product 9.5, a general neuronal marker; (2) leucocyte common antigen (LCA); and (3) Ulex europaeus I lectin, a marker of vascular endothelium. Image analysis was then used to determine the percentage area of immunostaining for LCA. Leucocytes were significantly more abundant in the pulp horn and mid-coronal region of intact and carious primary teeth, as compared to permanent teeth (P < 0.05, anova). Both dentitions demonstrated the presence of well-localized inflammatory cell infiltrates and marked aborization of pulpal nerves in areas of dense leucocyte accumulation. Primary and permanent tooth pulps appear to have a similar potential to mount inflammatory responses to gross caries The management of the compromised primary tooth pulp needs to be reappraised in the light of these findings.

Revisiting Street Intersections Using Slot-Based Systems.

Directory of Open Access Journals (Sweden)

Remi Tachet

Full Text Available Since their appearance at the end of the 19th century, traffic lights have been the primary mode of granting access to road intersections. Today, this centuries-old technology is challenged by advances in intelligent transportation, which are opening the way to new solutions built upon slot-based systems similar to those commonly used in aerial traffic: what we call Slot-based Intersections (SIs. Despite simulation-based evidence of the potential benefits of SIs, a comprehensive, analytical framework to compare their relative performance with traffic lights is still lacking. Here, we develop such a framework. We approach the problem in a novel way, by generalizing classical queuing theory. Having defined safety conditions, we characterize capacity and delay of SIs. In the 2-road crossing configuration, we provide a capacity-optimal SI management system. For arbitrary intersection configurations, near-optimal solutions are developed. Results theoretically show that transitioning from a traffic light system to SI has the potential of doubling capacity and significantly reducing delays. This suggests a reduction of non-linear dynamics induced by intersection bottlenecks, with positive impact on the road network. Such findings can provide transportation engineers and planners with crucial insights as they prepare to manage the transition towards a more intelligent transportation infrastructure in cities.

Recent Developments of Reflectarray Antennas for Reconfigurable Beams Using Surface-Mounted RF-MEMS

Directory of Open Access Journals (Sweden)

Eduardo Carrasco

2012-01-01

Full Text Available Some of the most recent developments in reconfigurable reflectarrays using surface-mounted RF-MEMS, which have been developed at the Universidad Politécnica de Madrid, are summarized in this paper. The results include reconfigurable elements based on patches aperture-coupled to delay lines in two configurations: single elements and gathered elements which form subarrays with common phase control. The former include traditional aperture-coupled elements and a novel wideband reflectarray element which has been designed using two stacked patches. The latter are proposed as a low cost solution for reducing the number of electronic control devices as well as the manufacturing complexity of large reflectarrays. The main advantages and drawbacks of the grouping are evaluated in both pencil and shaped-beam antennas. In all the cases, the effects of the MEMS switches and their assembly circuitry are evaluated when they are used in a 2-bit phase shifter which can be extended to more bits, demonstrating that the proposed elements can be used efficiently in reconfigurable-beam reflectarrays.

Single-nanoparticle detection with slot-mode photonic crystal cavities

Energy Technology Data Exchange (ETDEWEB)

Wang, Cheng; Kita, Shota; Lončar, Marko, E-mail: loncar@seas.harvard.edu [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Quan, Qimin [Rowland Institute at Harvard University, Cambridge, Massachusetts 02142 (United States); Li, Yihang [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States); Department of Electronic Engineering, Tsinghua University, Beijing 100084 (China)

2015-06-29

Optical cavities that are capable for detecting single nanoparticles could lead to great progress in early stage disease diagnostics and the study of biological interactions on the single-molecule level. In particular, photonic crystal (PhC) cavities are excellent platforms for label-free single-nanoparticle detection, owing to their high quality (Q) factors and wavelength-scale modal volumes. Here, we demonstrate the design and fabrication of a high-Q (>10{sup 4}) slot-mode PhC nanobeam cavity, which is able to strongly confine light in the slotted regions. The enhanced light-matter interaction results in an order of magnitude improvement in both refractive index sensitivity (439 nm/RIU) and single-nanoparticle sensitivity compared with conventional dielectric-mode PhC cavities. Detection of single polystyrene nanoparticles with radii of 20 nm and 30 nm is demonstrated in aqueous environments (D{sub 2}O), without additional laser and temperature stabilization techniques.

Static devices with new permanent magnets

International Nuclear Information System (INIS)

Chavanne, J.; Laforest, J.; Pauthenet, R.

1987-01-01

The high remanence and coercivity of the new permanent magnet materials are of special interest in the static applications. High ordering temperature and are uniaxial anisotropy at the origin of their good permanent magnet properties are obtained in rare earth-transition metal compounds. Binary SmCo/sub 5/ and Sm/sub 2/Co/sub 17/ and ternary Nd/sub 2/Fe/sub 14/B compounds are the basis materials of the best permanent magnets. new concepts of calculations of static devices with these magnets can be applied: the magnetization can be considered as ridig, the density of the surface Amperian current is constant, the relative permeability is approximately 1 and the induction calculations are linear. Examples of hexapoles with Sm-Co and NdFeB magnets are described and the performances are compared. The problems of temperature behavior and corrosion resistance are underlined

Tunable inkjet-printed slotted waveguide antenna on a ferrite substrate

KAUST Repository

Nafe, Ahmed; Farooqui, Muhammad; Shamim, Atif

2015-01-01

In this work an inkjet-printed frequency-tunable slotted waveguide antenna on a ferrite substrate is reported. Unlike the typical substrate integrated waveguide approach with via holes, a true 3D rectangular waveguide is realized by inkjet-printing

Broadband, Low Sidelobe, Zero Height, Slotted Circular Disk Antenna

African Journals Online (AJOL)

A rigorous mathematical theory for a rotationally symmetrical slotted circular disk antenna was developed. The theory applies the principle of "Gradient Invariance" of electromagnetic fields to determine the field components that are unique and single valued at any point in space. To detemine the radiation characteristics of ...

30 CFR 817.15 - Casing and sealing of underground openings: Permanent.

Science.gov (United States)

2010-07-01

... be designed to prevent access to the mine workings by people, livestock, fish and wildlife, machinery..., DEPARTMENT OF THE INTERIOR PERMANENT PROGRAM PERFORMANCE STANDARDS PERMANENT PROGRAM PERFORMANCE STANDARDS... shaft, drift, adit, tunnel, exploratory hole, entryway or other opening to the surface from underground...

Mechanical design and qualification of IR filter mounts and filter wheel of INSAT-3D sounder for low temperature

Science.gov (United States)

Vora, A. P.; Rami, J. B.; Hait, A. K.; Dewan, C. P.; Subrahmanyam, D.; Kirankumar, A. S.

2017-11-01

Next generation Indian Meteorological Satellite will carry Sounder instrument having subsystem of filter wheel measuring Ø260mm and carrying 18 filters arranged in three concentric rings. These filters made from Germanium, are used to separate spectral channels in IR band. Filter wheel is required to be cooled to 214K and rotated at 600 rpm. This Paper discusses the challenges faced in mechanical design of the filter wheel, mainly filter mount design to protect brittle germanium filters from failure under stresses due to very low temperature, compactness of the wheel and casings for improved thermal efficiency, survival under vibration loads and material selection to keep it lighter in weight. Properties of Titanium, Kovar, Invar and Aluminium materials are considered for design. The mount has been designed to accommodate both thermal and dynamic loadings without introducing significant aberrations into the optics or incurring permanent alignment shifts. Detailed finite element analysis of mounts was carried out for stress verification. Results of the qualification tests are discussed for given temperature range of 100K and vibration loads of 12g in Sine and 11.8grms in Random at mount level. Results of the filter wheel qualification as mounted in Electro Optics Module (EOM) are also presented.

A New Adaptive Self-Tuning Fourier Coefficients Algorithm for Periodic Torque Ripple Minimization in Permanent Magnet Synchronous Motors (PMSM

Directory of Open Access Journals (Sweden)

Gilberto Herrera-Ruíz

2013-03-01

Full Text Available A New Adaptive Self-Tuning Fourier Coefficients Algorithm for Periodic Torque Ripple Minimization in Permanent Magnet Synchronous Motors (PMSM Torque ripple occurs in Permanent Magnet Synchronous Motors (PMSMs due to the non-sinusoidal flux density distribution around the air-gap and variable magnetic reluctance of the air-gap due to the stator slots distribution. These torque ripples change periodically with rotor position and are apparent as speed variations, which degrade the PMSM drive performance, particularly at low speeds, because of low inertial filtering. In this paper, a new self-tuning algorithm is developed for determining the Fourier Series Controller coefficients with the aim of reducing the torque ripple in a PMSM, thus allowing for a smoother operation. This algorithm adjusts the controller parameters based on the component’s harmonic distortion in time domain of the compensation signal. Experimental evaluation is performed on a DSP-controlled PMSM evaluation platform. Test results obtained validate the effectiveness of the proposed self-tuning algorithm, with the Fourier series expansion scheme, in reducing the torque ripple.

A new adaptive self-tuning Fourier coefficients algorithm for periodic torque ripple minimization in permanent magnet synchronous motors (PMSM).

Science.gov (United States)

Gómez-Espinosa, Alfonso; Hernández-Guzmán, Víctor M; Bandala-Sánchez, Manuel; Jiménez-Hernández, Hugo; Rivas-Araiza, Edgar A; Rodríguez-Reséndiz, Juvenal; Herrera-Ruíz, Gilberto

2013-03-19

A New Adaptive Self-Tuning Fourier Coefficients Algorithm for Periodic Torque Ripple Minimization in Permanent Magnet Synchronous Motors (PMSM) Torque ripple occurs in Permanent Magnet Synchronous Motors (PMSMs) due to the non-sinusoidal flux density distribution around the air-gap and variable magnetic reluctance of the air-gap due to the stator slots distribution. These torque ripples change periodically with rotor position and are apparent as speed variations, which degrade the PMSM drive performance, particularly at low speeds, because of low inertial filtering. In this paper, a new self-tuning algorithm is developed for determining the Fourier Series Controller coefficients with the aim of reducing the torque ripple in a PMSM, thus allowing for a smoother operation. This algorithm adjusts the controller parameters based on the component's harmonic distortion in time domain of the compensation signal. Experimental evaluation is performed on a DSP-controlled PMSM evaluation platform. Test results obtained validate the effectiveness of the proposed self-tuning algorithm, with the Fourier series expansion scheme, in reducing the torque ripple.

Corrosion behaviour of Nd-Fe-B permanent magnets

International Nuclear Information System (INIS)

Mummert, K.; El-Aziz, A.M.; Barkleit, G.; Schultz, L.; Rodewald, W.

2000-01-01

The corrosion behaviour of Nd-Fe-B permanent magnetic alloys as well as of single phases of these alloys have been investigated in sulphuric acid at room temperature and humid air at 150 C using mass loss and electrochemical techniques. Scanning electron microscopy and scanning probe microscopy were used to study the surface topography. The electrostatic surface potential was examined by scanning probe microscopy using tapping mode. A correlation between the electrostatic surface potential and the corrosion rate of these alloys was found. The higher the value of the electrostatic surface potential of the intergranular phases the higher is the corrosion sensitivity. The strength of the corrosion attack on the phases of sintered permanent magnetic alloys is as follows: Ferromagnetic phase < B-rich phase < Nd-rich phase. The differences in the chemical composition as well as in the preparation of these magnetic alloys have distinct influence on the corrosion resistance of the magnetic Nd-Fe-B alloys. (orig.)

A reactor core with accurately positioned fuel-batteries

International Nuclear Information System (INIS)

Borrman, B.E.

1976-01-01

A reactor core of containing a grid for a plurality of fuel batteries each of which is constituted by several claddings containing fuel-rods, said grid comprising square members mainly and being located at the core upper-end, each square member surrounding a group of four fuel batteries, spring-contacts being mounted between the fuel batteries and the grid, slots being provided between the batteries for the four arms of a centrally mounted cross-slaped control-rod, each slot being provided at the grid-level, with a flexible spacing device, the overall spacing of whork determining the (a+2b)- dimension is equal to, or higher than, the largest thickness of arm D of the above-mentioned control-rod, said spacing device constituting one of the control-rails the fuel batteries fixed to the fuel-element envelope, as well as the control-rails fixed to the grid, characterized in that each battery control-rail forms a closing surface at right angles to the wall of the adjacent battery and directed toward the grid nearest surface in contact with the above-mentioned control-rail. (author)

The rediscovery of synchronous reluctance and ferrite permanent magnet motors tutorial course notes

CERN Document Server

Pellegrino, Gianmario; Bianchi, Nicola; Soong, Wen; Cupertino, Francesco

2016-01-01

This book offers an essential compendium on the analysis and design of synchronous motors for variable-speed applications. Focusing on synchronous reluctance and ferrite permanent-magnet (PM) synchronous reluctance machines, it provides a broad perspective on three-phase machines for variable speed applications, a field currently dominated by asynchronous machines and rare-earth PM synchronous machines. It also describes synchronous reluctance machines and PM machines without rare-earth materials, comparing them to state-of-the-art solutions. The book provides readers with extensive information on and finite element models of PM synchronous machines, including all relevant equations and with an emphasis on synchronous-reluctance and PM-assisted synchronous-reluctance machines. It covers ferrite-assisted machines, modeled as a subcase of PM-assistance, fractional slot combinations solutions, and a quantitative, normalized comparison of torque capability with benchmark PM machines. The book discusses a wealth o...

An Experimental and Numerical Investigation of Endwall Aerodynamics and Heat Transfer in a Gas Turbine Nozzle Guide Vane with Slot Film Cooling

Science.gov (United States)

Alqefl, Mahmood Hasan

In many regions of the high-pressure gas turbine, film cooling flows are used to protect the turbine components from the combustor exit hot gases. Endwalls are challenging to cool because of the complex system of secondary flows that disturb surface film coolant coverage. The secondary flow vortices wash the film coolant from the surface into the mainstream significantly decreasing cooling effectiveness. In addition to being effected by secondary flow structures, film cooling flow can also affect these structures by virtue of their momentum exchange. In addition, many studies in the literature have shown that endwall contouring affects the strength of passage secondary flows. Therefore, to develop better endwall cooling schemes, a good understanding of passage aerodynamics and heat transfer as affected by interactions of film cooling flows with secondary flows is required. This experimental and computational study presents results from a linear, stationary, two-passage cascade representing the first stage nozzle guide vane of a high-pressure gas turbine with an axisymmetrically contoured endwall. The sources of film cooling flows are upstream combustor liner coolant and endwall slot film coolant injected immediately upstream of the cascade passage inlet. The operating conditions simulate combustor exit flow features, with a high Reynolds number of 390,000 and approach flow turbulence intensity of 11% with an integral length scale of 21% of the chord length. Measurements are performed with varying slot film cooling mass flow to mainstream flow rate ratios (MFR). Aerodynamic effects are documented with five-hole probe measurements at the exit plane. Heat transfer is documented through recovery temperature measurements with a thermocouple. General secondary flow features are observed. Total pressure loss measurements show that varying the slot film cooling MFR has some effects on passage loss. Velocity vectors and vorticity distributions show a very thin, yet intense

Slot-type pickup/kicker for AA stochastic cooling

CERN Multimedia

CERN PhotoLab

1979-01-01

A "slotted transmission line" was used for both pickups and kickers of the stochastic cooling systems of the AA. They served for the cooling of the high-density antiproton stack, in momentum and both transverse planes. In the beginning in a single band, 1-2 GHz, later in 2 bands, 2-4 and 4-8 GHz. See also 7906190, 7906193.

Enhanced and selective optical trapping in a slot-graphite photonic crystal.

Science.gov (United States)

Krishnan, Aravind; Huang, Ningfeng; Wu, Shao-Hua; Martínez, Luis Javier; Povinelli, Michelle L

2016-10-03

Applicability of optical trapping tools for nanomanipulation is limited by the available laser power and trap efficiency. We utilized the strong confinement of light in a slot-graphite photonic crystal to develop high-efficiency parallel trapping over a large area. The stiffness is 35 times higher than our previously demonstrated on-chip, near field traps. We demonstrate the ability to trap both dielectric and metallic particles of sub-micron size. We find that the growth kinetics of nanoparticle arrays on the slot-graphite template depends on particle size. This difference is exploited to selectively trap one type of particle out of a binary colloidal mixture, creating an efficient optical sieve. This technique has rich potential for analysis, diagnostics, and enrichment and sorting of microscopic entities.

Abrasive-waterjet cutting of thick concrete and waterjet cleaning for nuclear facility decommissioning and decontamination

International Nuclear Information System (INIS)

Echert, D.C.; Hashish, M.; Marvin, M.H.

1987-01-01

Two tools have been developed for use by the nuclear industry: the Deep Kerf tool and the Cleaner/Scarifier tool. The Deep Kerf tool is designed to cut through thick, reinforced concrete structures to facilitate their decommissioning. It employs the abrasive-waterjet (AWJ) cutting technology. The basis of the system is a rotary nozzle that makes a slot in the concrete wide enough to accommodate the cutting tool as it advances. In this program, concrete as thick as 1.5 m was cut through from one side. A shroud and vacuum system covers the opening of the slot during cutting to contain the spoils with greater than 99% efficiency. The Cleaner/Scarifier tool was designed for removing the surface layers of contaminated concrete and decontaminating metal surfaces. It uses ultrahigh-pressure waterjets mounted on a rotating arm to remove or clean the target surface. Spoils recovery with a shroud and vacuum system is over 99% complete for both horizontal and vertical surfaces

Constraint-based local search for container stowage slot planning

DEFF Research Database (Denmark)

Pacino, Dario; Jensen, Rune Møller; Bebbington, Tom

2012-01-01

-sea vessels. This paper describes the constrained-based local search algorithm used in the second phase of this approach where individual containers are assigned to slots in each bay section. The algorithm can solve this problem in an average of 0.18 seconds per bay, corresponding to a 20 seconds runtime...

Design of Ultra-Wideband Tapered Slot Antenna by Using Binomial Transformer with Corrugation

Science.gov (United States)

Chareonsiri, Yosita; Thaiwirot, Wanwisa; Akkaraekthalin, Prayoot

2017-05-01

In this paper, the tapered slot antenna (TSA) with corrugation is proposed for UWB applications. The multi-section binomial transformer is used to design taper profile of the proposed TSA that does not involve using time consuming optimization. A step-by-step procedure for synthesis of the step impedance values related with step slot widths of taper profile is presented. The smooth taper can be achieved by fitting the smoothing curve to the entire step slot. The design of TSA based on this method yields results with a quite flat gain and wide impedance bandwidth covering UWB spectrum from 3.1 GHz to 10.6 GHz. To further improve the radiation characteristics, the corrugation is added on the both edges of the proposed TSA. The effects of different corrugation shapes on the improvement of antenna gain and front-to-back ratio (F-to-B ratio) are investigated. To demonstrate the validity of the design, the prototypes of TSA without and with corrugation are fabricated and measured. The results show good agreement between simulation and measurement.

Mount Protects Thin-Walled Glass or Ceramic Tubes from Large Thermal and Vibration Loads

Science.gov (United States)

Amato, Michael; Schmidt, Stephen; Marsh. James; Dahya, Kevin

2011-01-01

The design allows for the low-stress mounting of fragile objects, like thin walled glass, by using particular ways of compensating, isolating, or releasing the coefficient of thermal expansion (CTE) differences between the mounted object and the mount itself. This mount profile is lower than true full kinematic mounting. Also, this approach enables accurate positioning of the component for electrical and optical interfaces. It avoids the higher and unpredictable stress issues that often result from potting the object. The mount has been built and tested to space-flight specifications, and has been used for fiber-optic, optical, and electrical interfaces for a spaceflight mission. This mount design is often metal and is slightly larger than the object to be mounted. The objects are optical or optical/electrical, and optical and/or electrical interfaces are required from the top and bottom. This requires the mount to be open at both ends, and for the object s position to be controlled. Thin inside inserts at the top and bottom contact the housing at defined lips, or edges, and hold the fragile object in the mount. The inserts can be customized to mimic the outer surface of the object, which further reduces stress. The inserts have the opposite CTE of the housing material, partially compensating for the CTE difference that causes thermal stress. A spring washer is inserted at one end to compensate for more CTE difference and to hold the object against the location edge of the mount for any optical position requirements. The spring also ensures that any fiber-optic or optic interface, which often requires some pressure to ensure a good interface, does not overstress the fragile object. The insert thickness, material, and spring washer size can be traded against each other to optimize the mount and stresses for various thermal and vibration load ranges and other mounting requirements. The alternate design uses two separate, unique features to reduce stress and hold the

Adaptive fuzzy dynamic surface control for the chaotic permanent magnet synchronous motor using Nussbaum gain

Energy Technology Data Exchange (ETDEWEB)

Luo, Shaohua [School of Automation, Chongqing University, Chongqing 400044, China and College of Mechanical Engineering, Hunan University of Arts and Science, Hunan 415000 (China)

2014-09-01

This paper is concerned with the problem of adaptive fuzzy dynamic surface control (DSC) for the permanent magnet synchronous motor (PMSM) system with chaotic behavior, disturbance and unknown control gain and parameters. Nussbaum gain is adopted to cope with the situation that the control gain is unknown. And the unknown items can be estimated by fuzzy logic system. The proposed controller guarantees that all the signals in the closed-loop system are bounded and the system output eventually converges to a small neighborhood of the desired reference signal. Finally, the numerical simulations indicate that the proposed scheme can suppress the chaos of PMSM and show the effectiveness and robustness of the proposed method.

A three-dimensional algebraic grid generation scheme for gas turbine combustors with inclined slots

Science.gov (United States)

Yang, S. L.; Cline, M. C.; Chen, R.; Chang, Y. L.

1993-01-01

A 3D algebraic grid generation scheme is presented for generating the grid points inside gas turbine combustors with inclined slots. The scheme is based on the 2D transfinite interpolation method. Since the scheme is a 2D approach, it is very efficient and can easily be extended to gas turbine combustors with either dilution hole or slot configurations. To demonstrate the feasibility and the usefulness of the technique, a numerical study of the quick-quench/lean-combustion (QQ/LC) zones of a staged turbine combustor is given. Preliminary results illustrate some of the major features of the flow and temperature fields in the QQ/LC zones. Formation of co- and counter-rotating bulk flow and shape temperature fields can be observed clearly, and the resulting patterns are consistent with experimental observations typical of the confined slanted jet-in-cross flow. Numerical solutions show the method to be an efficient and reliable tool for generating computational grids for analyzing gas turbine combustors with slanted slots.

Ultra-flattened nearly-zero dispersion and ultrahigh nonlinear slot silicon photonic crystal fibers with ultrahigh birefringence

Science.gov (United States)

Liao, Jianfei; Xie, Yingmao; Wang, Xinghua; Li, Dongbo; Huang, Tianye

2017-07-01

A slot silicon photonic crystal fiber (PCF) is proposed to simultaneously achieve ultrahigh birefringence, large nonlinearity and ultra-flattened nearly-zero dispersion over a wide wavelength range. By taking advantage on the slot effect, ultrahigh birefringence up to 0.0736 and ultrahigh nonlinear coefficient up to 211.48 W-1 m-1 for quasi-TE mode can be obtained at the wavelength of 1.55 μm. Moreover, ultra-flattened dispersion of 0.49 ps/(nm km) for quasi-TE mode can be achieved over a 180 nm wavelength range with low dispersion slope of 1.85 × 10-3 ps/(nm2 km) at 1.55 μm. Leveraging on these advantages, the proposed slot PCF has great potential for efficient all-optical signal processing applications.

Dual Band a-Si:H Solar-Slot Antenna for 2.4/5.2GHz WLAN Applications

Directory of Open Access Journals (Sweden)

S. V. Shynu

2009-12-01

Full Text Available A simple and compact design of solar-slot antenna for dual band 2.4/5.2GHz wireless local area networks (WLAN applications is proposed. The design employs amorphous silicon (a-Si:H solar cells in polyimide substrate with an embedded twin strip slot structure to generate dual resonant frequencies. A T-shaped microstripline feed is used to excite the twin slot in the a-Si:H solar cell. The measured impedance bandwidths for the proposed solar antenna are 25.9% (642 MHz centered at 2.482 GHz and 8.2% (420 MHz centered at 5.098 GHz. The measured gain at 2.4 and 5.2 GHz are 3.1 dBi and 2.1 dBi respectively.

Design of a Short/Open-Ended Slot Antenna with Capacitive Coupling Feed Strips for Hepta-Band Mobile Application

Directory of Open Access Journals (Sweden)

Kyoseung Keum

2018-01-01

Full Text Available In this paper, a planar printed hybrid short/open-ended slot antenna with capacitive coupling feed strips is proposed for hepta-band mobile applications. The proposed antenna is comprised of a slotted ground plane on the top plane and two capacitive coupling feed strips with a chip inductor on the bottom plane. At the low frequency band, the short-ended long slot fed by strip 1 generates its half-wavelength resonance mode, whereas the T-shaped open ended slot fed by strip 2 generates its quarter-wavelength resonance mode for the high frequency band. The antenna provides a wide bandwidth covering GSM850/GSM900/DCS/PCS/UMTS/LTE2300/LTE2500 operation bands. Moreover, the antenna occupies a small volume of 15 mm × 50 mm × 1 mm. The operating principle of the proposed antenna and the simulation/measurement results are presented and discussed.

Photovoltaic module mounting clip with integral grounding

Science.gov (United States)

Lenox, Carl J.

2010-08-24

An electrically conductive mounting/grounding clip, usable with a photovoltaic (PV) assembly of the type having an electrically conductive frame, comprises an electrically conductive body. The body has a central portion and first and second spaced-apart arms extending from the central portion. Each arm has first and second outer portions with frame surface-disrupting element at the outer portions.

Altering the "Near-Miss" Effect in Slot Machine Gamblers

Science.gov (United States)

Dixon, Mark R.; Nastally, Becky L.; Jackson, James E.; Habib, Reza

2009-01-01

This study investigated the potential for recreational gamblers to respond as if certain types of losing slot machine outcomes were actually closer to a win than others (termed the "near-miss effect"). Exposure to conditional discrimination training and testing disrupted this effect for 10 of the 16 participants. These 10 participants demonstrated…

Small slot waveguide rings for on-chip quantum optical circuits.

Science.gov (United States)

Rotenberg, Nir; Türschmann, Pierre; Haakh, Harald R; Martin-Cano, Diego; Götzinger, Stephan; Sandoghdar, Vahid

2017-03-06

Nanophotonic interfaces between single emitters and light promise to enable new quantum optical technologies. Here, we use a combination of finite element simulations and analytic quantum theory to investigate the interaction of various quantum emitters with slot-waveguide rings. We predict that for rings with radii as small as 1.44 μm, with a Q-factor of 27,900, near-unity emitter-waveguide coupling efficiencies and emission enhancements on the order of 1300 can be achieved. By tuning the ring geometry or introducing losses, we show that realistic emitter-ring systems can be made to be either weakly or strongly coupled, so that we can observe Rabi oscillations in the decay dynamics even for micron-sized rings. Moreover, we demonstrate that slot waveguide rings can be used to directionally couple emission, again with near-unity efficiency. Our results pave the way for integrated solid-state quantum circuits involving various emitters.

Self-suspended permanent magnetic FePt ferrofluids

KAUST Repository

Dallas, Panagiotis; Kelarakis, Antonios; Sahore, Ritu; DiSalvo, Francis J.; Livi, Sebastien; Giannelis, Emmanuel P.

2013-01-01

on the surface of L10 FePt nanoparticles. In contrast, all types of ferrofluids previously reported employ either volatile solvents as the suspending media or superparamagnetic iron oxide nanoparticles (that lacks permanent magnetization) as the inorganic

Perspective with Landsat Overlay, Mount Kilimanjaro, Tanzania

Science.gov (United States)

2002-01-01

Mount Kilimanjaro (Kilima Njaro or 'shining mountain' in Swahili), the highest point in Africa, reaches 5,895 meters (19,340 feet) above sea level, tall enough to maintain a permanent snow cap despite being just 330 kilometers (210 miles) south of the equator. It is the tallest free-standing mountain on the Earth's land surface world, rising about 4,600 meters (15,000 feet) above the surrounding plain. Kilimanjaro is a triple volcano (has three peaks) that last erupted perhaps more than 100,000 years ago but still exudes volcanic gases. It is accompanied by about 20 other nearby volcanoes, some of which are seen to the west (left) in this view, prominently including Mount Meru, which last erupted only about a century ago. The volcanic mountain slopes are commonly fertile and support thick forests, while the much drier grasslands of the plains are home to elephants, lions, and other savanna wildlife.This 3-D perspective view was generated using topographic data from the Shuttle Radar Topography Mission (SRTM), a Landsat 7 satellite image, and a false sky. Topographic expression is vertically exaggerated two times.Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and

A Minimax Network Flow Model for Characterizing the Impact of Slot Restrictions

Science.gov (United States)

Lee, Douglas W.; Patek, Stephen D.; Alexandrov, Natalia; Bass, Ellen J.; Kincaid, Rex K.

2010-01-01

This paper proposes a model for evaluating long-term measures to reduce congestion at airports in the National Airspace System (NAS). This model is constructed with the goal of assessing the global impacts of congestion management strategies, specifically slot restrictions. We develop the Minimax Node Throughput Problem (MINNTHRU), a multicommodity network flow model that provides insight into air traffic patterns when one minimizes the worst-case operation across all airports in a given network. MINNTHRU is thus formulated as a model where congestion arises from network topology. It reflects not market-driven airline objectives, but those of a regulatory authority seeking a distribution of air traffic beneficial to all airports, in response to congestion management measures. After discussing an algorithm for solving MINNTHRU for moderate-sized (30 nodes) and larger networks, we use this model to study the impacts of slot restrictions on the operation of an entire hub-spoke airport network. For both a small example network and a medium-sized network based on 30 airports in the NAS, we use MINNTHRU to demonstrate that increasing the severity of slot restrictions increases the traffic around unconstrained hub airports as well as the worst-case level of operation over all airports.

Shoulder-Mounted Robot for MRI-guided arthrography: Accuracy and mounting study.

Science.gov (United States)

Monfaredi, R; Wilson, E; Sze, R; Sharma, K; Azizi, B; Iordachita, I; Cleary, K

2015-08-01

A new version of our compact and lightweight patient-mounted MRI-compatible 4 degree-of-freedom (DOF) robot for MRI-guided arthrography procedures is introduced. This robot could convert the traditional two-stage arthrography procedure (fluoroscopy-guided needle insertion followed by a diagnostic MRI scan) to a one-stage procedure, all in the MRI suite. The results of a recent accuracy study are reported. A new mounting technique is proposed and the mounting stability is investigated using optical and electromagnetic tracking on an anthropomorphic phantom. Five volunteer subjects including 2 radiologists were asked to conduct needle insertion in 4 different random positions and orientations within the robot's workspace and the displacement of the base of the robot was investigated during robot motion and needle insertion. Experimental results show that the proposed mounting method is stable and promising for clinical application.

30 CFR 816.15 - Casing and sealing of drilled holes: Permanent.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 3 2010-07-01 2010-07-01 false Casing and sealing of drilled holes: Permanent...-SURFACE MINING ACTIVITIES § 816.15 Casing and sealing of drilled holes: Permanent. When no longer needed... exploration hole, other drilled hole or borehole, well, and other exposed underground opening shall be capped...

Micro-structured rough surfaces by laser etching for heat transfer enhancement on flush mounted heat sinks

International Nuclear Information System (INIS)

Ventola, L; Scaltrito, L; Ferrero, S; Chiavazzo, E; Asinari, P; Maccioni, G

2014-01-01

The aim of this work is to improve heat transfer performances of flush mounted heat sinks used in electronic cooling. To do this we patterned 1.23 cm 2 heat sinks surfaces by microstructured roughnesses built by laser etching manufacturing technique, and experimentally measured the convective heat transfer enhancements due to different patterns. Each roughness differs from the others with regards to the number and the size of the micro-fins (e.g. the micro- fin length ranges from 200 to 1100 μm). Experimental tests were carried out in forced air cooling regime. In particular fully turbulent flows (heating edge based Reynolds number ranging from 3000 to 17000) were explored. Convective heat transfer coefficient of the best micro-structured heat sink is found to be roughly two times compared to the smooth heat sinks one. In addition, surface area roughly doubles with regard to smooth heat sinks, due to the presence of micro-fins. Consequently, patterned heat sinks thermal transmittance [W/K] is found to be roughly four times the smooth heat sinks one. We hope this work may open the way for huge boost in the technology of electronic cooling by innovative manufacturing techniques.

Modeling and characterization of electret based vibration energy harvesters in slot-effect configuration

International Nuclear Information System (INIS)

Renaud, M; Altena, G; Elfrink, R; Goedbloed, M; De Nooijer, C; Van Schaijk, R

2015-01-01

The purpose of this article is to elaborate a model and the optimization guidelines for electret based harvesters with a specific electret/electrodes configuration, namely the slot-effect configuration. Slot-effect configured harvesters have been investigated experimentally by several research groups. A model describing their dynamic behavior has also been recently proposed in the literature. However, the simplifications used in the existing model can lead to inaccuracies and a refined analysis is elaborated in the present article. The model is compared with experimental measurements on MEMS fabricated devices with a corrugated electret. The electrodes dimensioning in the MEMS device are chosen so that the harvester behaves in a quasi-linear manner over its full range of displacement. This quasi-linearity simplifies greatly the device optimization. Indeed, the behavior of the developed electrostatic harvester is shown to be very comparable to that of piezoelectric harvesters, which are very well understood and documented. The influence of several design parameters on output power performance is investigated. As long as pull-in and breakdown voltage effects can be avoided, the electret surface potential should be maximized and the air gap minimized. We also investigate theoretically the influence of three types of electret on the generated power: planar, corrugated with partial charge coverage, and corrugated with full charge coverage. With the dimensions corresponding to our MEMS devices, the output power characteristics for the three types of electret are similar. However, it is shown that this is not always true. In some conditions, corrugated electrets with full charge coverage are detrimental for the generated power. (paper)

Slot-type pickup/kicker for AA stochastic cooling

CERN Multimedia

1979-01-01

A "slotted transmission line" was used for both pickups and kickers of the stochastic cooling systems of the AA. They served for the cooling of the high-density antiproton stack, in momentum and both transverse planes. In the beginning, in a single band, 1-2 GHz, later in 2 bands, 2-4 and 4-8 GHz. View down the centre of a pickup or kicker. See also 7906189, 7906190, 7906583.

Photovoltaic array mounting apparatus, systems, and methods

Science.gov (United States)

West, John Raymond; Atchley, Brian; Hudson, Tyrus Hawkes; Johansen, Emil

2014-12-02

An apparatus for mounting a photovoltaic (PV) module on a surface, including a support with an upper surface, a lower surface, tabs, one or more openings, and a clip comprising an arm and a notch, where the apparatus resists wind forces and seismic forces and creates a grounding electrical bond between the PV module, support, and clip. The invention further includes a method for installing PV modules on a surface that includes arranging supports in rows along an X axis and in columns along a Y axis on a surface such that in each row the distance between two neighboring supports does not exceed the length of the longest side of a PV module and in each column the distance between two neighboring supports does not exceed the length of the shortest side of a PV module.

Design and experimental validation for direct-drive fault-tolerant permanent-magnet vernier machines.

Science.gov (United States)

Liu, Guohai; Yang, Junqin; Chen, Ming; Chen, Qian

2014-01-01

A fault-tolerant permanent-magnet vernier (FT-PMV) machine is designed for direct-drive applications, incorporating the merits of high torque density and high reliability. Based on the so-called magnetic gearing effect, PMV machines have the ability of high torque density by introducing the flux-modulation poles (FMPs). This paper investigates the fault-tolerant characteristic of PMV machines and provides a design method, which is able to not only meet the fault-tolerant requirements but also keep the ability of high torque density. The operation principle of the proposed machine has been analyzed. The design process and optimization are presented specifically, such as the combination of slots and poles, the winding distribution, and the dimensions of PMs and teeth. By using the time-stepping finite element method (TS-FEM), the machine performances are evaluated. Finally, the FT-PMV machine is manufactured, and the experimental results are presented to validate the theoretical analysis.

Design and Experimental Validation for Direct-Drive Fault-Tolerant Permanent-Magnet Vernier Machines

Directory of Open Access Journals (Sweden)

Guohai Liu

2014-01-01

Full Text Available A fault-tolerant permanent-magnet vernier (FT-PMV machine is designed for direct-drive applications, incorporating the merits of high torque density and high reliability. Based on the so-called magnetic gearing effect, PMV machines have the ability of high torque density by introducing the flux-modulation poles (FMPs. This paper investigates the fault-tolerant characteristic of PMV machines and provides a design method, which is able to not only meet the fault-tolerant requirements but also keep the ability of high torque density. The operation principle of the proposed machine has been analyzed. The design process and optimization are presented specifically, such as the combination of slots and poles, the winding distribution, and the dimensions of PMs and teeth. By using the time-stepping finite element method (TS-FEM, the machine performances are evaluated. Finally, the FT-PMV machine is manufactured, and the experimental results are presented to validate the theoretical analysis.

Contribution of experimental fluid mechanics to the design of vertical slot fish passes

Directory of Open Access Journals (Sweden)

Wang R.W.

2010-02-01

Full Text Available This paper presents the main results of an experimental study of mean and turbulent characteristics of flow in a scale model of a vertical slot fish pass with varying width and slope (from 5% to 15%. Experimental hydraulic modelling was combined with the study of fish behaviour in the model. The discharge coefficient, which significantly affects the design of such facilities, varied from 0.67 to 0.89 and was strongly influenced by the slope. Two distinct flow patterns were observed, depending on the slope and the fish pass width. The point of transition between the two states was determined. Low velocity areas are likely resting zones for fish and particular attention was paid to evaluating these areas. Slope was found to affect both the volume of the low velocity zone, and the value of turbulent kinetic energy in these areas. The statistical characteristics of turbulent kinetic energy in the pools were linked primarily to the maximum velocity in the jet. An analysis of the behaviour of juvenile brown trout (Salmo trutta in the scale model clearly showed that the fish avoided the areas of high velocities in the jet, except at the slot itself where they took advantage of the jet’s non-stationary character. Low-velocity areas were not frequented uniformly by fish, which stayed most frequently in the zone located just downstream from the slot and behind the small side baffle. It is suggested that future studies might investigate lower pool-length to slot-width ratios, which might make it possible to increase the slope significantly and should also examine ways of improving hydraulic conditions for fish by carefully distributing obstacles in pools.

High speed operation of permanent magnet machines

Science.gov (United States)

El-Refaie, Ayman M.

This work proposes methods to extend the high-speed operating capabilities of both the interior PM (IPM) and surface PM (SPM) machines. For interior PM machines, this research has developed and presented the first thorough analysis of how a new bi-state magnetic material can be usefully applied to the design of IPM machines. Key elements of this contribution include identifying how the unique properties of the bi-state magnetic material can be applied most effectively in the rotor design of an IPM machine by "unmagnetizing" the magnet cavity center posts rather than the outer bridges. The importance of elevated rotor speed in making the best use of the bi-state magnetic material while recognizing its limitations has been identified. For surface PM machines, this research has provided, for the first time, a clear explanation of how fractional-slot concentrated windings can be applied to SPM machines in order to achieve the necessary conditions for optimal flux weakening. A closed-form analytical procedure for analyzing SPM machines designed with concentrated windings has been developed. Guidelines for designing SPM machines using concentrated windings in order to achieve optimum flux weakening are provided. Analytical and numerical finite element analysis (FEA) results have provided promising evidence of the scalability of the concentrated winding technique with respect to the number of poles, machine aspect ratio, and output power rating. Useful comparisons between the predicted performance characteristics of SPM machines equipped with concentrated windings and both SPM and IPM machines designed with distributed windings are included. Analytical techniques have been used to evaluate the impact of the high pole number on various converter performance metrics. Both analytical techniques and FEA have been used for evaluating the eddy-current losses in the surface magnets due to the stator winding subharmonics. Techniques for reducing these losses have been

Laser Doppler vibrometry experiment on a piezo-driven slot synthetic jet in water

Directory of Open Access Journals (Sweden)

Broučková Zuzana

2015-01-01

Full Text Available The present study deals with a slot synthetic jet (SJ issuing from an actuator into quiescent surroundings and driven by a piezoceramic transducer. The actuator slot width was 0.36 mm, with a drive frequency proposed near the theoretical natural frequency of the actuator. The working fluid was water at room temperature. The present experiments used flow visualization (a laser-induced fluorescence technique and laser Doppler vibrometry methods. Flow visualization was used to identify SJ formation, to demonstrate its function, and to estimate SJ velocity. Laser Doppler vibrometry was used to quantify diaphragm displacement and refine operating parameters. Phase averaging yielded a spatial and temporal diaphragm deflection during the actuation period. Taking incompressibility and continuity into consideration, the velocity in the actuator slot and the Reynolds number of the SJ were evaluated as 0.21 m/s and 157, respectively. The present results confirmed a SJ actuator function at the resonance frequency of approximately 46 Hz, which corresponds closely with the theoretical evaluation. The laser Doppler vibrometry results corresponded closely with an estimation of SJ velocity by the present flow visualization.

Photogrammetric Analysis of the Current Dome-Building Eruption of Mount St. Helens Volcano

Science.gov (United States)

Diefenbach, A. K.; Dzurisin, D.; Crider, J. G.; Schilling, S. P.

2006-12-01

Beginning in October 2004 and continuing to present day, the eruption of Mount St. Helens has provided a unique opportunity to experiment with new tools and techniques to study the dome-building eruption of a Cascade volcano. At the onset of eruption, a permanent camera station called Sugar Bowl was installed on the northeast rim of the crater about 2 km from the vent. Since that time, four additional cameras have been installed on the rim and crater floor to provide continuous visual observation of dome growth and crater conditions. We have analyzed images from four of the cameras to measure variations in three-dimensional lineal growth rates of lava spines extruding from the growing dome. Using photogrammetric techniques it is possible to obtain quantitative information on the geometry and displacement of a changing topographic model, in this case the evolving dome and glaciers in the crater of Mount St. Helens. The technique is an inexpensive, high-resolution, and efficient method that uses standard commercial software and an off-the-shelf digital camera to determine the x, y, z positions of selected points on the model surface. The model geometry at any given time is defined by the positions of all the points, and displacements are measured by tracking the changing positions of the points through time. Lineal extrusion rates during the first few months of the eruption ranged from 6-11 m/d, and subsequent estimates by other techniques were 4-5 m/d (Dzurisin et. al, 2005). For the past six months the extrusion rate has leveled off at 1 m/d, possibly indicative of steady-state extrusion or an approaching pause in the eruption. Another aspect of the project involves the use of overlapping oblique photos taken from a helicopter in 2004 and 2005 to produce fast and coarse digital elevation models (DEMs), which supplement high resolution DEMs produced by the USGS every 1 - 2 months. Comparing these results with seismicity and ground tilt measured by shallow borehole

Performance comparison of three-phase flux reversal permanent magnet motors in BLDC and BLAC operation mode

International Nuclear Information System (INIS)

Stumberger, B.; Stumberger, G.; Hadziselimovic, M.; Hamler, A.; Gorican, V.; Jesenik, M.; Trlep, M.

2008-01-01

The paper presents a comparison of torque capability and flux-weakening performance of three-phase flux reversal permanent magnet motors with surface and inset permanent magnets. Finite element analysis is employed to determine the performance of each motor in BLDC and BLAC operation mode. It is shown that the torque capability and flux-weakening performance of surface or inset permanent magnet configuration is strongly dependent on the stator teeth number/rotor pole number combination

Fatigue damage behavior of a surface-mount electronic package under different cyclic applied loads

Science.gov (United States)

Ren, Huai-Hui; Wang, Xi-Shu

2014-04-01

This paper studies and compares the effects of pull-pull and 3-point bending cyclic loadings on the mechanical fatigue damage behaviors of a solder joint in a surface-mount electronic package. The comparisons are based on experimental investigations using scanning electron microscopy (SEM) in-situ technology and nonlinear finite element modeling, respectively. The compared results indicate that there are different threshold levels of plastic strain for the initial damage of solder joints under two cyclic applied loads; meanwhile, fatigue crack initiation occurs at different locations, and the accumulation of equivalent plastic strain determines the trend and direction of fatigue crack propagation. In addition, simulation results of the fatigue damage process of solder joints considering a constitutive model of damage initiation criteria for ductile materials and damage evolution based on accumulating inelastic hysteresis energy are identical to the experimental results. The actual fatigue life of the solder joint is almost the same and demonstrates that the FE modeling used in this study can provide an accurate prediction of solder joint fatigue failure.

Experimental Results from a Flat Plate, Turbulent Boundary Layer Modified for the Purpose of Drag Reduction

Science.gov (United States)

Elbing, Brian R.

2006-11-01

Recent experiments on a flat plate, turbulent boundary layer at high Reynolds numbers (>10^7) were performed to investigate various methods of reducing skin friction drag. The methods used involved injecting either air or a polymer solution into the boundary layer through a slot injector. Two slot injectors were mounted on the model with one located 1.4 meters downstream of the nose and the second located 3.75 meters downstream. This allowed for some synergetic experiments to be performed by varying the injections from each slot and comparing the skin friction along the plate. Skin friction measurements were made with 6 shear stress sensors flush mounted along the stream-wise direction of the model.

Flush mounting of thin film sensors

Science.gov (United States)

Moore, Thomas C., Sr. (Inventor)

1992-01-01

Flush mounting of a sensor on a surface is provided by first forming a recessed area on the surface. Next, an adhesive bonding mixture is introduced into the recessed area. The adhesive bonding mixture is chosen to provide thermal expansion matching with the surface surrounding the recessed area. A strip of high performance polymeric tape is provided, with the sensor attached to the underside thereof, and the tape is positioned over the recessed area so that it acts as a carrier of the sensor. A shim having flexibility so that it will conform to the surface surrounding the recessed area is placed over the tape, and a vacuum pad is placed over the shim. The area above the surface is then evacuated while holding the sensor flush with the surface during curing of the adhesive bonding mixture. After such curing, the pad, shim, and tape are removed from the sensor, electrical connections for the sensor are provided, after which the remaining space in the recessed area is filled with a polymeric foam.

Error Floor Analysis of Coded Slotted ALOHA over Packet Erasure Channels

DEFF Research Database (Denmark)

Ivanov, Mikhail; Graell i Amat, Alexandre; Brannstrom, F.

2014-01-01

We present a framework for the analysis of the error floor of coded slotted ALOHA (CSA) for finite frame lengths over the packet erasure channel. The error floor is caused by stopping sets in the corresponding bipartite graph, whose enumeration is, in general, not a trivial problem. We therefore ...... identify the most dominant stopping sets for the distributions of practical interest. The derived analytical expressions allow us to accurately predict the error floor at low to moderate channel loads and characterize the unequal error protection inherent in CSA.......We present a framework for the analysis of the error floor of coded slotted ALOHA (CSA) for finite frame lengths over the packet erasure channel. The error floor is caused by stopping sets in the corresponding bipartite graph, whose enumeration is, in general, not a trivial problem. We therefore...

[Measurement of plasma parameters in slot microplasma by optical emission spectrum].

Science.gov (United States)

Dong, Li-Fang; Lü, Ying-Hui; Liu, Wei-Yuan; Yue, Han; Lu, Ning; Li, Xin-Chun

2010-12-01

Slot microplasma was generated in argon and air mixture by using dielectric barrier discharge device with two parallel water electrodes. The molecular vibrational temperature, molecular rotational temperature and average electron energy of the slot plasma were studied by optical emission spectrum. The molecular vibrational temperature was calculated using the second positive system of nitrogen molecules ( C3 pi(u) --> B3 pi(g)). The molecular rotational temperature was calculated using the first negative system of nitrogen molecular ions ( B 2sigma(u)+ --> X sigma(g)+). The relative intensities of the first negative system of nitrogen molecular ions (391.4 nm) and nitrogen molecules in the excitation level (337.1 nm) emission spectrum line were measured for studying the variations of electron energy. It was found that the molecular vibrational temperature, molecular rotational temperature and average electron energy decrease with gas pressure increasing.

Analysis of adjusting effects of mounting force on frequency conversion of mounted nonlinear optics.

Science.gov (United States)

Su, Ruifeng; Liu, Haitao; Liang, Yingchun; Lu, Lihua

2014-01-10

Motivated by the need to increase the second harmonic generation (SHG) efficiency of nonlinear optics with large apertures, a novel mounting configuration with active adjusting function on the SHG efficiency is proposed and mechanically and optically studied. The adjusting effects of the mounting force on the distortion and stress are analyzed by the finite element methods (FEM), as well as the contribution of the distortion and stress to the change in phase mismatch, and the SHG efficiency are theoretically stated. Further on, the SHG efficiency is calculated as a function of the mounting force. The changing trends of the distortion, stress, and the SHG efficiency with the varying mounting force are obtained, and the optimal ones are figured out. Moreover, the mechanism of the occurrence of the optimal values is studied and the adjusting strategy is put forward. Numerical results show the robust adjustment of the mounting force, as well as the effectiveness of the mounting configuration, in increasing the SHG efficiency.

Microwave Backscatter-Based Wireless Temperature Sensor Fabricated by an Alumina-Backed Au Slot Radiation Patch.

Science.gov (United States)

Lu, Fei; Wang, Haixing; Guo, Yanjie; Tan, Qiulin; Zhang, Wendong; Xiong, Jijun

2018-01-16

A wireless and passive temperature sensor operating up to 800 °C is proposed. The sensor is based on microwave backscatter RFID (radio frequency identification) technology. A thin-film planar structure and simple working principle make the sensor easy to operate under high temperature. In this paper, the proposed high temperature sensor was designed, fabricated, and characterized. Here the 99% alumina ceramic with a dimension of 40 mm × 40 mm × 1 mm was prepared in micromechanics for fabrication of the sensor substrate. The metallization of the Au slot patch was realized in magnetron sputtering with a slot width of 2 mm and a slot length of 32 mm. The measured resonant frequency of the sensor at 25 °C is 2.31 GHz. It was concluded that the resonant frequency decreases with the increase in the temperature in range of 25-800 °C. It was shown that the average sensor sensitivity is 101.94 kHz/°C.

Development of Disk Rover, wall-climbing robot using permanent magnet disk

International Nuclear Information System (INIS)

Hirose, Shigeo; Tsutsumitake; Hiroshi; Toyama, Ryousei; Kobayashi, Kengo.

1992-01-01

A new type of wall climbing robot, named Disk Rover, using permanent magnet disks are developed. The newly introduced permanent magnet disk is to rotate the magnet disk on the surface of wall with partly contacted posture. It allows to produce high magnetic attraction force compared with conventional permanent wheel which utilizes only a small portion of the magnet installed around the wheel. The optimum design of the magnetic wheel is done by using finit element method and it is shown that the magnetic attraction force vs. weight ratio can be designed about three times higher than conventional type magnet wheel. The developed Disk Rover is 25 kg in weight including controller and battery, about 685 mm in diameter, 239 mm in height and has a pair of permanent magnet disks. It is demonstrated by the experiments that the Disk Rover can move around on the surface of the wall quite smoothly by radio control and has payload of about its own weight. Several considerations are also done in order to surmount bead weld. (author)

Genetic Diversity of Plasmodium falciparum Merozoite Surface Protein-1 Block 2 in Sites of Contrasting Altitudes and Malaria Endemicities in the Mount Cameroon Region

OpenAIRE

Wanji, Samuel; Kengne-Ouafo, Arnaud J.; Joan Eyong, Ebanga E.; Kimbi, Helen K.; Tendongfor, Nicholas; Ndamukong-Nyanga, Judith L.; Nana-Djeunga, Hugues C.; Bourguinat, Catherine; Sofeu-Feugaing, David D.; Charvet, Claude L.

2012-01-01

The present study analyzed the relationship between the genetic diversity of Plasmodium falciparum and parasitologic/entomologic indices in the Mount Cameroon region by using merozoite surface protein 1 as a genetic marker. Blood samples were collected from asymptomatic children from three altitude zones (high, intermediate, and low). Parasitologic and entomologic indices were determined by microscopy and landing catch mosquito collection/circumsporozoite protein–enzyme-linked immunosorbent a...

Linearly tapered slot antenna circular array for mobile communications

Science.gov (United States)

Simons, Rainee N.; Kelly, Eron; Lee, Richard Q.; Taub, Susan R.

1993-01-01

The design, fabrication and testing of a conformal K-band circular array is presented. The array consists of sixteen linearly tapered slot antennas (LTSA). It is fed by a 1:16 microstrip line power splitter via electromagnetic coupling. The array has an omni-directional pattern in the azimuth plane. In the elevation plane the beam is displaced above the horizon.

broadband, low sidelobe, zero height, slotted circular disk antenna

African Journals Online (AJOL)

of argument rr where J? = jwµ.(slot of the antenna can be obtained by substituting 'Tr', hack into the field equations. The results are given hy the ...

Creating New Child Care Slots in Mini Child Care Centers: Big Bang for the Buck in New Jersey.

Science.gov (United States)

Frankel, Arthur J.; And Others

1992-01-01

Small grants of $7,500 with technical assistance were offered to the child care community of New Jersey to either start or increase licensed capacity in mini-child care centers. Results of a subsequent analysis showed that 26 grantees created 481 new child care slots at an average cost of $561 per slot. (Author/SM)

The Effect of Slot-Code Optimization in Warehouse Order Picking

Directory of Open Access Journals (Sweden)

Andrea Fumi

2013-07-01

most appropriate material handling resource configuration. Building on previous work on the effect of slot-code optimization on travel times in single/dual command cycles, the authors broaden the scope to include the most general picking case, thus widening the range of applicability and realising former suggestions for future research.

Simple gambling or sophisticated gaming? : applying game analysis methods to modern video slot machine games

OpenAIRE

Leppäsalko, Tero

2017-01-01

Slot machine games have become the most popular form of gambling worldwide. In Finland, their pervasiveness in public spaces and popularity makes them one of the most common form of gaming. However, in game studies, gambling games are often regarded as borderline games due to the player’s lack of control. In this thesis I ask whether modern video slot machine games can be considered as games and if so, what similarities there are between them and contemporary video games. To find out if m...

Prestressing Effects on the Performance of Concrete Beams with Near-surface-mounted Carbon-fiber-reinforced Polymer Bars

Science.gov (United States)

Hong, Sungnam; Park, Sun-Kyu

2016-07-01

The effects of various prestressing levels on the flexural behavior of concrete beams strengthened with prestressed near-surface-mounted (NSM) carbon-fiber-reinforced polymer (CFRP) bars were investigated in this study. Four-point flexural tests up to failure were performed using a total of six strengthened prestressed and nonprestressed concrete beams. The nonprestressed strengthened beam failed by premature debonding at the interface of concrete and the epoxy adhesive, but the prestressed one failed owing due to rupture of the CFRP bar. As the prestressing level of the CFRP bar increased, the cracking and yield loads of the prestressed beams increased, but its effect on their deflections was insignificant. The ultimate load was constant regardless of prestressing level, but the ultimate deflection was almost inversely proportional to the level.

The impact of different stator and rotor slot number combinations on iron losses of a three-phase induction motor at no-load

International Nuclear Information System (INIS)

Marcic, T.; Stumberger, B.; Stumberger, G.; Hadziselimovic, M.; Zagradisnik, I.

2008-01-01

The electromechanical characteristics of induction motors depend on the used stator and rotor slot combination. The correlation between the usage of different stator and rotor slot number combinations, magnetic flux density distributions, no-load iron losses and rated load winding over-temperatures for a specific induction motor is presented. The motor's magnetic field was analyzed by traces of the magnetic flux density vector, obtained by FEM. Post-processing of FE magnetic field solution was used for posterior iron loss calculation of the motor iron loss at no-load. The examined motor stator lamination had 36 semi-closed slots and the rotor laminations had 28, 33, 34, 44 and 46 semi-closed slots

On-chip broadband ultra-compact optical couplers and polarization splitters based on off-centered and non-symmetric slotted Si-wire waveguides

Science.gov (United States)

Haldar, Raktim; Mishra, V.; Dutt, Avik; Varshney, Shailendra K.

2016-10-01

In this work, we propose novel schemes to design on-chip ultra-compact optical directional couplers (DC) and broadband polarization beam splitters (PBS) based on off-centered and asymmetric dielectric slot waveguides, respectively. Slot dimensions and positions are optimized to achieve maximum coupling coefficients between two symmetric and non-symmetric slotted Si wire waveguides through overlap integral method. We observe >88% of enhancement in the coupling coefficients when the size-optimized slots are placed in optimal positions, with respect to the same waveguides with no slot. When the waveguides are parallel, in that case, a coupling length as short as 1.73 μm is accomplished for TM mode with the off-centered and optimized slots. This scheme enables us to design optical DC with very small footprint, L c ∼ 0.9 μm in the presence of S-bends. We also report a compact (L c ∼ 1.1 μm) on-chip broadband PBS with hybrid slots. Extinction ratios of 13 dB and 22.3 dB are realized with very low insertion loss (0.055 dB and 0.008 dB) for TM and TE modes at 1.55 μm, respectively. The designed PBS exhibits a bandwidth of 78 nm for the TM mode (C-and partial L-bands) and >100 nm for the TE mode (S + C + L wavelength bands). Such on-chip devices can be used to design compact photonic interconnects and quantum information processing units efficiently. We have also investigated the fabrication tolerances of the proposed devices and described the fabrication steps to realize such hybrid devices. Our results are in good agreement with 3D FDTD simulations.

Mounting for ceramic scroll

Science.gov (United States)

Petty, Jack D.

1993-01-01

A mounting for a ceramic scroll on a metal engine block of a gas turbine engine includes a first ceramic ring and a pair of cross key connections between the first ceramic ring, the ceramic scroll, and the engine block. The cross key connections support the scroll on the engine block independent of relative radial thermal growth and for bodily movement toward an annular mounting shoulder on the engine. The scroll has an uninterrupted annular shoulder facing the mounting shoulder on the engine block. A second ceramic ring is captured between mounting shoulder and the uninterrupted shoulder on the scroll when the latter is bodily shifted toward the mouting shoulder to define a gas seal between the scroll and the engine block.

Refractive index and temperature sensitivity characteristics of a micro-slot fiber Bragg grating.

Science.gov (United States)

Saffari, Pouneh; Yan, Zhijun; Zhou, Kaiming; Zhang, Lin

2012-07-10

Fabrication and characterization of a UV inscribed fiber Bragg grating (FBG) with a micro-slot liquid core is presented. Femtosecond (fs) laser patterning/chemical etching technique was employed to engrave a micro-slot with dimensions of 5.74 μm(h)×125 μm(w)×1388.72 μm(l) across the whole grating. The device has been evaluated for refractive index (RI) and temperature sensitivities and exhibited distinctive thermal response and RI sensitivity beyond the detection limit of reported fiber gratings. This structure has not just been RI sensitive, but also maintained the robustness comparing with the bare core FBGs and long-period gratings with the partial cladding etched off.

Compact SOI optimized slot microring coupled phase-shifted Bragg grating resonator for sensing

Science.gov (United States)

Zhao, Chao Ying; Zhang, Lei; Zhang, Cheng Mei

2018-05-01

We propose a novel sensor structure composed of a slot microring and a phase-shifted sidewall Bragg gratings in a slot waveguide. We first present a theoretical analysis of transmission by using the transfer matrix. Then, the mode-field distributions of transmission spectrum obtained from 3D simulations based on FDTD method demonstrates that our sensor exhibit theoretical sensitivity of 297 . 13 nm / RIU, a minimum detection limit of 1 . 1 × 10-4 RIU, the maximum extinction ratio of 20 dB, the quality factor of 2 × 103 and a compact dimension-theoretical structure of 15 μm × 8 . 5 μm. Finally, the sensor's performance is simulated for NaCl solution.

Solar panel truss mounting systems and methods

Energy Technology Data Exchange (ETDEWEB)

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell; Goodman, Joseph; Nolan, Wade; Pitelka, Taylor; Rahimzadeh, Keyan; Brooks, Bradley; Lohr, Joshua; Crooks, Ryan; Porges, Jamie; Rubin, Daniel

2016-06-28

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the base rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.

Solar panel truss mounting systems and methods

Energy Technology Data Exchange (ETDEWEB)

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell; Goodman, Joseph; Nolan, Wade; Pitelka, Taylor; Rahimzadeh, Keyan; Brooks, Bradley; Lohr, Joshua; Crooks, Ryan; Porges, Jamie; Rubin, Daniel

2018-01-30

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the base rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.

Solar panel truss mounting systems and methods

Science.gov (United States)

Al-Haddad, Tristan Farris; Cavieres, Andres; Gentry, Russell; Goodman, Joseph; Nolan, Wade; Pitelka, Taylor; Rahimzadeh, Keyan; Brooks, Bradley; Lohr, Joshua; Crooks, Ryan; Porges, Jamie; Rubin, Daniel

2015-10-20

An exemplary embodiment of the present invention provides a solar panel truss mounting system comprising a base and a truss assembly coupled to the base. The truss assembly comprises a first panel rail mount, second panel rail mount parallel to the first panel rail mount, base rail mount parallel to the first and second panel rail mounts, and a plurality of support members. A first portion of the plurality of support members extends between the first and second panel rail mounts. A second portion of the plurality of support members extends between the first panel rail mount and the base rail mount. A third portion of the plurality of support members extends between the second panel rail mount and the base rail mount. The system can further comprise a plurality of connectors for coupling a plurality of photovoltaic solar panels to the truss assembly.

Dual Circularly Polarized Omnidirectional Antenna with Slot Array on Coaxial Cylinder

Directory of Open Access Journals (Sweden)

Bin Zhou

2015-01-01

Full Text Available A dual circularly polarized (CP omnidirectional antenna based on slot array in coaxial cylinder structure is presented in this paper. It is constructed by perpendicular slot pairs around and along the axis of the coaxial cylinder to realize the omnidirectional CP property, and two ports are assigned in its two sides as left hand circularly polarized (LHCP port and right hand circularly polarized (RHCP port, respectively. The proposed antenna achieves a bandwidth of 16.4% ranging from 5.05 to 5.95 GHz with an isolation higher than 15 dB between the two CP ports, and the return loss (RL is higher than 10 dB within the bandwidth in both of the two ports. From the measured results, the average axial ratio (AR of the proposed antenna in omnidirectional plane is lower than 1.5 dB.

Adjustable bipod flexures for mounting mirrors in a space telescope.

Science.gov (United States)

Kihm, Hagyong; Yang, Ho-Soon; Moon, Il Kweon; Yeon, Jeong-Heum; Lee, Seung-Hoon; Lee, Yun-Woo

2012-11-10

A new mirror mounting technique applicable to the primary mirror in a space telescope is presented. This mounting technique replaces conventional bipod flexures with flexures having mechanical shims so that adjustments can be made to counter the effects of gravitational distortion of the mirror surface while being tested in the horizontal position. Astigmatic aberration due to the gravitational changes is effectively reduced by adjusting the shim thickness, and the relation between the astigmatism and the shim thickness is investigated. We tested the mirror interferometrically at the center of curvature using a null lens. Then we repeated the test after rotating the mirror about its optical axis by 180° in the horizontal setup, and searched for the minimum system error. With the proposed flexure mount, the gravitational stress at the adhesive coupling between the mirror and the mount is reduced by half that of a conventional bipod flexure for better mechanical safety under launch loads. Analytical results using finite element methods are compared with experimental results from the optical interferometer. Vibration tests verified the mechanical safety and optical stability, and qualified their use in space applications.

The development of permanent isolation surface barriers: Hanford Site, Richland, Washington, U.S.A

International Nuclear Information System (INIS)

Wing, N.R.; Gee, G.W.

1993-01-01

Permanent isolation surface barriers are being developed to isolate wastes disposed of in situ (in place) at the US Department of Energy's Hanford Site in Washington State (USA). The current focus of development efforts is to design barriers that will function in a semiarid to subhumid climate, Emit infiltration and percolation of water through the waste zone to near-zero amounts, be maintenance free, and last up to 1000 years or more. A series of field tests, experiments, and lysimeter studies have been conducted for several years. The results of tests to date confirm that the Hanford barrier concepts are valid for both present and wetter climatic conditions. The data collected also have provided the foundation for the design of a large prototype barrier to be constructed later in 1993. This paper presents the results of some of the field tests, experiments, and lysimeter studies

The head-mounted microscope.

Science.gov (United States)

Chen, Ting; Dailey, Seth H; Naze, Sawyer A; Jiang, Jack J

2012-04-01

Microsurgical equipment has greatly advanced since the inception of the microscope into the operating room. These advancements have allowed for superior surgical precision and better post-operative results. This study focuses on the use of the Leica HM500 head-mounted microscope for the operating phonosurgeon. The head-mounted microscope has an optical zoom from 2× to 9× and provides a working distance from 300 mm to 700 mm. The headpiece, with its articulated eyepieces, adjusts easily to head shape and circumference, and offers a focus function, which is either automatic or manually controlled. We performed five microlaryngoscopic operations utilizing the head-mounted microscope with successful results. By creating a more ergonomically favorable operating posture, a surgeon may be able to obtain greater precision and success in phonomicrosurgery. Phonomicrosurgery requires the precise manipulation of long-handled cantilevered instruments through the narrow bore of a laryngoscope. The head-mounted microscope shortens the working distance compared with a stand microscope, thereby increasing arm stability, which may improve surgical precision. Also, the head-mounted design permits flexibility in head position, enabling operator comfort, and delaying musculoskeletal fatigue. A head-mounted microscope decreases the working distance and provides better ergonomics in laryngoscopic microsurgery. These advances provide the potential to promote precision in phonomicrosurgery. Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.

Geothermal Potential Analysis Using Landsat 8 and Sentinel 2 (Case Study: Mount Ijen)

Science.gov (United States)

Sukojo, B. M.; Mardiana, R.

2017-12-01

Geothermal energy is also a heat energy contained in the earth’s internal. Indonesia has a total geothermal potential of around 27 GWe. The government is eager for the development of geothermal in Indonesia can run well so that geothermal can act as one of the pillars of national energy. However, the geothermal potential has not been fully utilized. One of the geothermal potention is Mount Ijen. Mount Ijen is a strato volcano that has a crater lake with a depth of about 190 m and has a very high degree of acidity and the volume of lake water is very large. With the abundance of potential geothermal potential in Indonesia, it is necessary to have an activity in the form of integrated geoscience studies to be able to maximize the potential content that exists in a geothermal area. One of the studies conducted is to do potential mapping. This research performs image data processing of Landsat 8, Sentinel 2, RBI Map, and preliminary survey data. This research carried out the Vegetation Index, surface temperature and altitude. The equipment used in this research includes image processing software, number processing software, GPS Handheld and Laptop. Surface Temperatures in the Mount Ijen have anomalies with large temperatures ranging between 18° C to 38° C. The best correlation value of altitude and ground surface temperature is -0.89 ie the correlation of January surface temperature. While the correlation value of Landsat 8 and Sentinel 2 vegetation index was 0.81. The land cover confidence matrix scored 80%. Land cover in the research area is dominated by forests by 35% of the research area. There is a potential area of geothermal potential is very high on Mount Ijen with an area of 39.43 hectares located in Wongsorejo District and adjacent to District Sempol.

Iron Loss Prediction Using Modified IEM-Formula during the Field Weakening for Permanent Magnet Synchronous Machines

Directory of Open Access Journals (Sweden)

Pedram Asef

2017-12-01

Full Text Available During field weakening operation time (FWOT, the total iron loss rises and affects the accuracy of loss prediction and efficiency, especially if a large range of FWOT exists due to a large voltage drop that was rooted from the resistance of the used material. Iron loss prediction is widely employed in investigations for a fast electrical machine analysis using 2D finite element analysis (FEA. This paper proposes harmonic loss analytically by a steady-state equivalent circuit with a novel procedure. Consideration of skin effects and iron saturation are utilized in order to examine the accuracy through the relative error distribution in the frequency domain of each model from 50 to 700 Hz. Additionally, this comparative study presents a torque-frequency-field density calculation over each single term of the modified institute of electrical machines formula (IEM-Formula. The proposed analytical calculation is performed using 2D FEA for a classic and modified IEM-Formula along with experimental verifications on a surface-mounted permanent magnet synchronous generator (PMSG for a wind generation application.

Eddy current testing system for bottom mounted instrumentation welds

OpenAIRE

Kobayashi Noriyasu; Ueno Souichi; Suganuma Naotaka; Oodake Tatsuya; Maehara Takeshi; Kasuya Takashi; Ichikawa Hiroya

2015-01-01

The capability of eddy current testing (ECT) for the bottom mounted instrumentation (BMI) weld area of reactor vessel in a pressurized water reactor was demonstrated by the developed ECT system and procedure. It is difficult to position and move the probe on the BMI weld area because the area has complexly curved surfaces. The space coordinates and the normal vectors at the scanning points were calculated as the scanning trajectory of probe based on the measured results of surface shape on th...

Geology of the Ugashik-Mount Peulik Volcanic Center, Alaska

Science.gov (United States)

Miller, Thomas P.

2004-01-01

The Ugashik-Mount Peulik volcanic center, 550 km southwest of Anchorage on the Alaska Peninsula, consists of the late Quaternary 5-km-wide Ugashik caldera and the stratovolcano Mount Peulik built on the north flank of Ugashik. The center has been the site of explosive volcanism including a caldera-forming eruption and post-caldera dome-destructive activity. Mount Peulik has been formed entirely in Holocene time and erupted in 1814 and 1845. A large lava dome occupies the summit crater, which is breached to the west. A smaller dome is perched high on the southeast flank of the cone. Pyroclastic-flow deposits form aprons below both domes. One or more sector-collapse events occurred early in the formation of Mount Peulik volcano resulting in a large area of debris-avalanche deposits on the volcano's northwest flank. The Ugashik-Mount Peulik center is a calcalkaline suite of basalt, andesite, dacite, and rhyolite, ranging in SiO2 content from 51 to 72 percent. The Ugashik-Mount Peulik magmas appear to be co-genetic in a broad sense and their compositional variation has probably resulted from a combination of fractional crystallization and magma-mixing. The most likely scenario for a future eruption is that one or more of the summit domes on Mount Peulik are destroyed as new magma rises to the surface. Debris avalanches and pyroclastic flows may then move down the west and, less likely, east flanks of the volcano for distances of 10 km or more. A new lava dome or series of domes would be expected to form either during or within some few years after the explosive disruption of the previous dome. This cycle of dome disruption, pyroclastic flow generation, and new dome formation could be repeated several times in a single eruption. The volcano poses little direct threat to human population as the area is sparsely populated. The most serious hazard is the effect of airborne volcanic ash on aircraft since Mount Peulik sits astride heavily traveled air routes connecting the U

Influence of bracket-slot design on the forces released by superelastic nickel-titanium alignment wires in different deflection configurations.

Science.gov (United States)

Nucera, Riccardo; Gatto, Elda; Borsellino, Chiara; Aceto, Pasquale; Fabiano, Francesca; Matarese, Giovanni; Perillo, Letizia; Cordasco, Giancarlo

2014-05-01

To evaluate how different bracket-slot design characteristics affect the forces released by superelastic nickel-titanium (NiTi) alignment wires at different amounts of wire deflection. A three-bracket bending and a classic-three point bending testing apparatus were used to investigate the load-deflection properties of one superelastic 0.014-inch NiTi alignment wire in different experimental conditions. The selected NiTi archwire was tested in association with three bracket systems: (1) conventional twin brackets with a 0.018-inch slot, (2) a self-ligating bracket with a 0.018-inch slot, and (3) a self-ligating bracket with a 0.022-inch slot. Wire specimens were deflected at 2 mm and 4 mm. Use of a 0.018-inch slot bracket system, in comparison with use of a 0.022-inch system, increases the force exerted by the superelastic NiTi wires at a 2-mm deflection. Use of a self-ligating bracket system increases the force released by NiTi wires in comparison with the conventional ligated bracket system. NiTi wires deflected to a different maximum deflection (2 mm and 4 mm) release different forces at the same unloading data point (1.5 mm). Bracket design, type of experimental test, and amount of wire deflection significantly affected the amount of forces released by superelastic NiTi wires (Pwire's load during alignment.

Nonlinear Dynamic Surface Control of Chaos in Permanent Magnet Synchronous Motor Based on the Minimum Weights of RBF Neural Network

Directory of Open Access Journals (Sweden)

Shaohua Luo

2014-01-01

Full Text Available This paper is concerned with the problem of the nonlinear dynamic surface control (DSC of chaos based on the minimum weights of RBF neural network for the permanent magnet synchronous motor system (PMSM wherein the unknown parameters, disturbances, and chaos are presented. RBF neural network is used to approximate the nonlinearities and an adaptive law is employed to estimate unknown parameters. Then, a simple and effective controller is designed by introducing dynamic surface control technique on the basis of first-order filters. Asymptotically tracking stability in the sense of uniformly ultimate boundedness is achieved in a short time. Finally, the performance of the proposed controller is testified through simulation results.

Apoptosis in the human periodontal membrane evaluated in primary and permanent teeth

DEFF Research Database (Denmark)

Bille, Marie-Louise Bastholm; Thomsen, Bjarke; Kjær, Inger

2011-01-01

that resorption is connected to apoptosis of the epithelial cells of Malassez. The purpose of this study is to localize cells undergoing apoptosis in the periodontal membrane of human primary and permanent teeth. Materials and methods. Human primary and permanent teeth were examined immunohistochemically...... for apoptosis and epithelial cells of Malassez in the periodontal membrane. All teeth examined were extracted in connection with treatment. Results. Apoptosis was seen in close proximity to the root surface and within the epithelial cells of Malassez. This pattern of apoptotis is similar in the periodontal...... membrane in primary and permanent teeth. Conclusions. The inter-relationship between apoptotis and root resorption cannot be concluded from the present study. Apoptosis seen in close proximity to the root surface presumably corresponds to the highly innervated layer of the periodontal membrane...

View at the inside of the VELO-vessel: the RF-box with slots for the 2 Pile-Up and 21 VELO-modules. Also visible are the 2 ion getter pumps below the vessel and the belt that drives the x-movement of the module base.

CERN Multimedia

Jans, E

2007-01-01

Inside of the C-side of the VELO-vessel: the RF-box with slots for the 2 Pile-Up and 21 VELO-modules Interieur du cote C du vaisseau Velo.Transport in the pit towards the balcony.Lifting of the detector half out of the transport trolley.The detector half is being rotated over 90 degrees.The detector half ready to be lowered and mounted on the installation rail.Simultaneous fixation of the 3 bolts that connect the module base to the translation system.A-side of the VELO after installation of the detector half and before installation of the repeater crates.

Mount Zirkel Wilderness and vicinity, Colorado

International Nuclear Information System (INIS)

Snyder, G.L.; Patten, L.L.

1984-01-01

Several areas of metallic and nonmetallic mineralization have been identified from surface occurrences within the Mount Zirkel Wilderness and vicinity, Colorado. Three areas of probable copper-lead-zinc-silver-gold resource potential, two areas of probable chrome-platinum resource potential, four areas of probable uranium-thorium resource potential, two areas of probable molybdenum resource potential, and one area of probable fluorspar potential were identified by studies in 1965-1973 by the USGS and USBM. No potential for fossil fuel or geothermal resources was identified

Concentrated Windings in Compact Permanent Magnet Synchronous Generators: Managing Efficiency

Directory of Open Access Journals (Sweden)

Olivier Barré

2016-01-01

Full Text Available In electric power generation, customers want generators with high efficiency. Nowadays, modern turbo-generators have efficiencies greater than 98%. Although this amount should not be obtained for all kind of machines, efficiency will remain one of the main parameters for customer choice. Efficiency is also linked to the life of the machine: the higher the efficiency is, the longer the machine’s lifetime. During the past decade, new forms of energy production have appeared and generators have been developed to fit well into this market. For example, wind generators evolved towards permanent magnet generators having high polarity and running at low speed. Nevertheless, their structure is not fixed. An industrial company has built a prototype of such a generator which uses fractional-slot concentrated-windings (FSCW. This kind of winding is not the structure used by default in such electrical machines. Another field of interest is in autonomous generators which can be used on boats. Even if everyone has in mind large merchant ships, we must not forget smaller ships, such as fishing boats and short-range cruise ships, which spend the most of their time near the coast. This kind of ship does nothave large areas for installing the electric generation or the electric propulsion. It is the reason why, in this article, we focus on the efficiency of machines using fractional-slot concentrated-windings. In many publications which compare performances between distributed and concentrated windings, the result is almost the same. The efficiency of FSCW is not as high as the efficiency associated to the machines which are using distributed windings. Design methods have to be redrawn to integrate, as soon as possible, the loss mitigation in order to provide the best efficiency in power conversion. The following discussion, step by step, introduces the loss mitigation in every part of a machine using FSCW. To close the discussion, a design is produced and it

Coplanar Waveguide Fed Compact Wide Circular-Slotted Antenna for Wi-Fi/WiMAX Applications

Directory of Open Access Journals (Sweden)

M. Samsuzzaman

2014-01-01

Full Text Available A coplanar waveguide (CPW fed printing and wide circular slotted, dual band antenna for Wi-Fi/WiMAX applications are presented. The antenna mainly encompasses a ground with a wide circular slot in the centre, a rectangular feeding strip, and two pairs of symmetric planar inverted L (SPIL strips connecting with the slotted ground. The tuning effects of the rectangular patch, ground size, and SPIL strips to the resonance and matching condition are examined by HFSS and the prototype is fabricated and measured. The simulation and experimental results show that the antenna has an impedance bandwidth with −10 dB reflection coefficients 600 MHz (3.26–3.86 GHz, lower band and 1040 MHz (5.02–6.26 GHz, upper band, which can cover both the Wi-Fi 5.2/5.5/5.8 GHz and WiMAX 3.3/3.5/3.7/5.8 GHz bands. Moreover, a stable omnidirectional radiation pattern and average peak gain for lower band 3.23 dB and upper band 5.93 dB have been achieved, respectively.

Correction of Beam Distortion in Negative Hydrogen Ion Source with Multi-Slot Grounded Grid

International Nuclear Information System (INIS)

Tsumori, Katsuyoshi; Kaneko, Osamu; Takeiri, Yasuhiko; Oka, Yoshihide; Osakabe, Masaki; Ikeda, Katsunori; Nagaoka, Kenichi; Kawamoto, Toshikazu; Asano, Eiji; Sato, Mamoru; Kondo, Tomoki; Watanabe, Junko; Asano, Shiro; Suzuki, Yasuo

2005-01-01

The new beam accelerator with multi-slot grounded grid (MSGG) has been developed to increase the port-through power into large helical device (LHD). Using the accelerator, the maximum power of 5.7 MW was achieved at the beam energy of 186 keV in the beam injection to LHD plasma last year. Although the port-through power increased compared with conventional accelerators with multi-hole grounded grid (MHGG), the accelerator with the MSGG includes a disadvantage of bi-focal condition in parallel and perpendicular direction to the long side of the slots. When the beam width in one of those directions gets narrower, the width in another direction becomes wider. This disadvantage includes the loss of beam port-through power and induces internal damages in neutral beam line. In order to reduce the disadvantage, an experiment has been done using a small-scaled negative ion source with racetrack-shaped apertures for the steering grid installed at beam upstream of the MSGG. By applying the racetrack apertures to the accelerator, it is observed that the beam widths in the parallel and perpendicular directions to the slot long side have almost the same focal condition to obtain minimal beam widths

A design of scintillator tiles read out by surface-mounted SiPMs for a future hadron calorimeter

Energy Technology Data Exchange (ETDEWEB)

Liu, Yong; Bauss, Bruno; Buescher, Volker; Caudron, Julien; Chau, Phi; Degele, Reinhold; Geib, Karl-Heinrich; Masetti, Lucia; Schaefer, Ulrich; Tapprogge, Stefan; Wanke, Rainer [Institut fuer Physik and PRISMA Detector Lab, Johannes Gutenberg-Universitaet Mainz (Germany)

2015-07-01

Precision calorimetry using highly granular sampling calorimeters is being developed based on the particle flow concept within the CALICE collaboration. One design option of a hadron calorimeter is based on silicon photomultipliers (SiPMs) to detect photons generated in plastic scintillator tiles. Driven by the need of automated mass assembly of around ten millions of channels stringently required by the high granularity, we developed a design of scintillator tiles directly coupled with surface-mounted SiPMs. A cavity is created in the center of the bottom surface of each tile to provide enough room for the whole SiPM package and to improve collection of the light produced by incident particles penetrating the tile at different positions. The cavity design has been optimized using a GEANT4-based full simulation model to achieve high response to Minimum Ionizing Particles (MIPs) and also good areal uniformity. Cosmic-ray measurements confirms high 1-MIP response for scintillator tiles with an optimized cavity design. Uniformity measurements by scanning the tile area using focused electrons from a beta source show excellent response uniformity. This optimized design is well beyond the requirements for a precision hadron calorimeter.

Channel uranium-graphite reactor mounting

International Nuclear Information System (INIS)

Polushkin, K.K.; Kuznetsov, A.G.; Zheleznyakov, B.N.

1981-01-01

According to theoretical principles of general engineering technology the engineering experience of construction-mounting works at the NPP with channel uranium-graphite reactors is systematized. Main parameters and structural features of the 1000 MW channel uranium-graphite reactors are considered. The succession of mounting operations, premounting equipment and pipelines preparation and mounting works technique are described. The most efficient methods of fitting, welding and machining of reactor elements are recommended. Main problems of technical control service are discussed. A typical netted diagram of main equipment of channel uranium-graphite reactors mounting is given

Milk-run kanban system for raw printed circuit board withdrawal to surface-mounted equipment

Directory of Open Access Journals (Sweden)

Swee Li Chee

2012-12-01

Full Text Available Purpose:  The paper aims to present a case study and later simulation analysis on a kanban system that incorporating milk-run operation to draw in raw material to the process. Design/methodology/approach:  Data collection at the case study company for ten weeks followed by a process study called value stream mapping. The proposed kanban model is simulated to test its various performances including total output, average flow time, average work-in-process, SME utilization, and average waiting time. Response surface methodology is adopted to generate suitable representative regression models.  Findings: For all performance measures, simulation results showed that the proposed system consistently outperforms the push system currently practiced. Second, the system indicates the advantages of leveling, particularly in the event of machine failure and blockage. Third, operator in the proposed kanban system has a lower utilization, even with the additional material handling task.   Research limitations/implications: This study only begins to reveal the implication of leveling for production control on multi-machine scenario. The simulation of the system is solely based only the case study. The control parameters critical to the case study, were naturally used. The furtherance of the research should include generalizing the system and devising the respective methodology to facilitate wider applications. Practical implications: Originality/value:  The kanban system is proposed in the light of conflicting interests in handling the surface mounting and the related upstream processes. Such aspect is common to electronics assembly industry.

Sample mounting and transfer for coupling an ultrahigh vacuum variable temperature beetle scanning tunneling microscope with conventional surface probes

International Nuclear Information System (INIS)

Nafisi, Kourosh; Ranau, Werner; Hemminger, John C.

2001-01-01

We present a new ultrahigh vacuum (UHV) chamber for surface analysis and microscopy at controlled, variable temperatures. The new instrument allows surface analysis with Auger electron spectroscopy, low energy electron diffraction, quadrupole mass spectrometer, argon ion sputtering gun, and a variable temperature scanning tunneling microscope (VT-STM). In this system, we introduce a novel procedure for transferring a sample off a conventional UHV manipulator and onto a scanning tunneling microscope in the conventional ''beetle'' geometry, without disconnecting the heating or thermocouple wires. The microscope, a modified version of the Besocke beetle microscope, is mounted on a 2.75 in. outer diameter UHV flange and is directly attached to the base of the chamber. The sample is attached to a tripod sample holder that is held by the main manipulator. Under UHV conditions the tripod sample holder can be removed from the main manipulator and placed onto the STM. The VT-STM has the capability of acquiring images between the temperature range of 180--500 K. The performance of the chamber is demonstrated here by producing an ordered array of island vacancy defects on a Pt(111) surface and obtaining STM images of these defects

Report for slot cutter proof-of-principle test, Buried Waste Containment System project. Revision 1

International Nuclear Information System (INIS)

1998-01-01

Several million cubic feet of hazardous and radioactive waste was buried in shallow pits and trenches within many US Department of Energy (US DOE) sites. The pits and trenches were constructed similarly to municipal landfills with both stacked and random dump waste forms such as barrels and boxes. Many of the hazardous materials in these waste sites are migrating into groundwater systems through plumes and leaching. On-site containment is one of the options being considered for prevention of waste migration. This report describes the results of a proof-of-principle test conducted to demonstrate technology for containing waste. This proof-of-principle test, conducted at the RAHCO International, Inc., facility in the summer of 1997, evaluated equipment techniques for cutting a horizontal slot beneath an existing waste site. The slot would theoretically be used by complementary equipment designed to place a cement barrier under the waste. The technology evaluated consisted of a slot cutting mechanism, muck handling system, thrust system, and instrumentation. Data were gathered and analyzed to evaluate the performance parameters

Report for slot cutter proof-of-principle test, Buried Waste Containment System project. Revision 1

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-05-21

Several million cubic feet of hazardous and radioactive waste was buried in shallow pits and trenches within many US Department of Energy (US DOE) sites. The pits and trenches were constructed similarly to municipal landfills with both stacked and random dump waste forms such as barrels and boxes. Many of the hazardous materials in these waste sites are migrating into groundwater systems through plumes and leaching. On-site containment is one of the options being considered for prevention of waste migration. This report describes the results of a proof-of-principle test conducted to demonstrate technology for containing waste. This proof-of-principle test, conducted at the RAHCO International, Inc., facility in the summer of 1997, evaluated equipment techniques for cutting a horizontal slot beneath an existing waste site. The slot would theoretically be used by complementary equipment designed to place a cement barrier under the waste. The technology evaluated consisted of a slot cutting mechanism, muck handling system, thrust system, and instrumentation. Data were gathered and analyzed to evaluate the performance parameters.

Analysis and Design of a Permanent-Magnet Outer-Rotor Synchronous Generator for a Direct-Drive Vertical-Axis Wind Turbine

Directory of Open Access Journals (Sweden)

H. A. Lari

2014-12-01

Full Text Available In Permanent-Magnet Synchronous Generators (PMSGs the reduction of cogging torque is one of the most important problems in their performance and evaluation. In this paper, at first, a direct-drive vertical-axis wind turbine is chosen. According to its nominal value operational point, necessary parameters for the generator is extracted. Due to an analytical method, four generators with different pole-slot combinations are designed. Average torque, torque ripple and cogging torque are evaluated based on finite element method. The combination with best performance is chosen and with the analysis of variation of effective parameters on cogging torque, and introducing a useful method, an improved design of the PMSG with lowest cogging torque and maximum average torque is obtained. The results show a proper performance and a correctness of the proposed method.

Spontaneous decay of a single quantum dot coupled to a metallic slot waveguide in the presence of leaky plasmonic modes

DEFF Research Database (Denmark)

Chen, Yuntian; Gregersen, Niels; Nielsen, Torben Roland

2010-01-01

in which the metallic slot waveguide is embedded. Compared to the ideal case of a homogenous dielectric environment, the coupling efficiency of an emitter to a metallic slot waveguide is significantly reduced. We attribute the reduction to the coupling to leaky plasmonic modes. By increasing the refractive...

Root resorption of permanent incisors during three months of active orthodontic treatment.

Science.gov (United States)

Batool, Iffat; Abbas, Hasnain; Abbas, Assad; Abbas, Iram

2010-01-01

Root resorption is one of the most common and undesirable sequelea of orthodontic treatment. The aim of this study was to evaluate the amount of root resorption in permanent incisors during 3 month active period of fixed orthodontic appliance therapy using periapical radiographs. Periapical radiographs of a total of 138 permanent teeth (n = 138, mandibular n1 = 52, maxillary n2 = 86) were evaluated for root resorption. All patients were treated with 3M MBT multi-bonded, pre-adjusted appliances with 0.022 inch slots. Initial levelling and alignment was achieved with 0.0175 inch co-axial wires. All four incisors (maxillary and mandibular) were measured for any change in root length. The change in root length between T0 (pre-treatment) and T1 (post-treatment) was measured in millimetres and expressed in terms of percentage of original root length. The mean pre treatment (T0) root length for the maxillary teeth (n1 = 62) was 19.27 +/- 2.86 mm and 20.01 +/- 2.57 mm for the mandibular teeth (n2 = 31). The post-treatment (T1) root length for the maxillary teeth was 18.96 +/- 2.85 mm and 19.49 +/- 2.4 mm for the mandibular teeth showing a mean resorption of 0.31 mm and 0.52 mm for the maxillary and mandibular teeth respectively. Root resorption was strongly correlated with active orthodontic appliance therapy with maxillary and mandibular incisors being most susceptible. It was found that root resorption can be detected even in the early levelling and alignment stages of orthodontic treatment.

26 CFR 7.6041-1 - Return of information as to payments of winnings from bingo, keno, and slot machines.

Science.gov (United States)

2010-04-01

... winnings from bingo, keno, and slot machines. 7.6041-1 Section 7.6041-1 Internal Revenue INTERNAL REVENUE..., keno, and slot machines. (a) In general. On or after May 1, 1977, every person engaged in a trade or... machine play or of $1,500 or more from a keno game shall make an information return with respect to such...

Mount Athos: Between autonomy and statehood

Directory of Open Access Journals (Sweden)

Avramović Dragutin

2013-01-01

Full Text Available Legal status of the Mount Athos is characterized by many special features that make it internationally unique legal regime. The author analyzes peculiarities of Mount Athos territorial status, legal position of residents and visitors, as well as organization of Mount Athos authorities. The author concludes that the Mount Athos is characterized by a kind of para-sovereignty. Its autonomy involves not only the internal organization, autonomous governance and religious autonomy, but it also includes many elements of secular life of their visitors. Mount Athos has its own, separate legislative, administrative and judicial powers, while the Statute of the Mount Athos has greater legal force than all the other laws of the Greek state, because the state can not unilaterally change its provisions. Having in mind that the wide self-government is vested in church authorities and that the monks have very specific way of living, the author takes a position that the Mount Athos represent 'monastic state', but without statehood. The author also states that the Mount Athos will be faced with many challenges in the context of spreading of an assimilating, universal conception of human rights.

Optical datacenter network employing slotted (TDMA) operation for dynamic resource allocation

Science.gov (United States)

Bakopoulos, P.; Tokas, K.; Spatharakis, C.; Patronas, I.; Landi, G.; Christodoulopoulos, K.; Capitani, M.; Kyriakos, A.; Aziz, M.; Reisis, D.; Varvarigos, E.; Zahavi, E.; Avramopoulos, H.

2018-02-01

The soaring traffic demands in datacenter networks (DCNs) are outpacing progresses in CMOS technology, challenging the bandwidth and energy scalability of currently established technologies. Optical switching is gaining traction as a promising path for sustaining the explosive growth of DCNs; however, its practical deployment necessitates extensive modifications to the network architecture and operation, tailored to the technological particularities of optical switches (i.e. no buffering, limitations in radix size and speed). European project NEPHELE is developing an optical network infrastructure that leverages optical switching within a software-defined networking (SDN) framework to overcome the bandwidth and energy scaling challenges of datacenter networks. An experimental validation of the NEPHELE data plane is reported based on commercial off-the-shelf optical components controlled by FPGA boards. To facilitate dynamic allocation of the network resources and perform collision-free routing in a lossless network environment, slotted operation is employed (i.e. using time-division multiple-access - TDMA). Error-free operation of the NEPHELE data plane is verified for 200 μs slots in various scenarios that involve communication between Ethernet hosts connected to custom-designed top-of-rack (ToR) switches, located in the same or in different datacenter pods. Control of the slotted data plane is obtained through an SDN framework comprising an OpenDaylight controller with appropriate add-ons. Communication between servers in the optical-ToR is demonstrated with various routing scenarios, concerning communication between hosts located in the same rack or in different racks, within the same or different datacenter pods. Error-free operation is confirmed for all evaluated scenarios, underpinning the feasibility of the NEPHELE architecture.

Peri-Elastodynamic Simulations of Guided Ultrasonic Waves in Plate-Like Structure with Surface Mounted PZT

Directory of Open Access Journals (Sweden)

Subir Patra

2018-01-01

Full Text Available Peridynamic based elastodynamic computation tool named Peri-elastodynamics is proposed herein to simulate the three-dimensional (3D Lamb wave modes in materials for the first time. Peri-elastodynamics is a nonlocal meshless approach which is a scale-independent generalized technique to visualize the acoustic and ultrasonic waves in plate-like structure, micro-electro-mechanical systems (MEMS and nanodevices for their respective characterization. In this article, the characteristics of the fundamental Lamb wave modes are simulated in a sample plate-like structure. Lamb wave modes are generated using a surface mounted piezoelectric (PZT transducer which is actuated from the top surface. The proposed generalized Peri-elastodynamics method is not only capable of simulating two dimensional (2D in plane wave under plane strain condition formulated previously but also capable of accurately simulating the out of plane Symmetric and Antisymmetric Lamb wave modes in plate like structures in 3D. For structural health monitoring (SHM of plate-like structures and nondestructive evaluation (NDE of MEMS devices, it is necessary to simulate the 3D wave-damage interaction scenarios and visualize the different wave features due to damages. Hence, in addition, to simulating the guided ultrasonic wave modes in pristine material, Lamb waves were also simulated in a damaged plate. The accuracy of the proposed technique is verified by comparing the modes generated in the plate and the mode shapes across the thickness of the plate with theoretical wave analysis.

Peri-Elastodynamic Simulations of Guided Ultrasonic Waves in Plate-Like Structure with Surface Mounted PZT.

Science.gov (United States)

Patra, Subir; Ahmed, Hossain; Banerjee, Sourav

2018-01-18

Peridynamic based elastodynamic computation tool named Peri-elastodynamics is proposed herein to simulate the three-dimensional (3D) Lamb wave modes in materials for the first time. Peri-elastodynamics is a nonlocal meshless approach which is a scale-independent generalized technique to visualize the acoustic and ultrasonic waves in plate-like structure, micro-electro-mechanical systems (MEMS) and nanodevices for their respective characterization. In this article, the characteristics of the fundamental Lamb wave modes are simulated in a sample plate-like structure. Lamb wave modes are generated using a surface mounted piezoelectric (PZT) transducer which is actuated from the top surface. The proposed generalized Peri-elastodynamics method is not only capable of simulating two dimensional (2D) in plane wave under plane strain condition formulated previously but also capable of accurately simulating the out of plane Symmetric and Antisymmetric Lamb wave modes in plate like structures in 3D. For structural health monitoring (SHM) of plate-like structures and nondestructive evaluation (NDE) of MEMS devices, it is necessary to simulate the 3D wave-damage interaction scenarios and visualize the different wave features due to damages. Hence, in addition, to simulating the guided ultrasonic wave modes in pristine material, Lamb waves were also simulated in a damaged plate. The accuracy of the proposed technique is verified by comparing the modes generated in the plate and the mode shapes across the thickness of the plate with theoretical wave analysis.

Optical slotted circuit switched network: a bandwidth efficient alternative to wavelength-routed network

Science.gov (United States)

Li, Yan; Collier, Martin

2007-11-01

Wavelength-routed networks have received enormous attention due to the fact that they are relatively simple to implement and implicitly offer Quality of Service (QoS) guarantees. However, they suffer from a bandwidth inefficiency problem and require complex Routing and Wavelength Assignment (RWA). Most attempts to address the above issues exploit the joint use of WDM and TDM technologies. The resultant TDM-based wavelength-routed networks partition the wavelength bandwidth into fixed-length time slots organized as a fixed-length frame. Multiple connections can thus time-share a wavelength and the grooming of their traffic leads to better bandwidth utilization. The capability of switching in both wavelength and time domains in such networks also mitigates the RWA problem. However, TMD-based wavelength-routed networks work in synchronous mode and strict synchronization among all network nodes is required. Global synchronization for all-optical networks which operate at extremely high speed is technically challenging, and deploying an optical synchronizer for each wavelength involves considerable cost. An Optical Slotted Circuit Switching (OSCS) architecture is proposed in this paper. In an OSCS network, slotted circuits are created to better utilize the wavelength bandwidth than in classic wavelength-routed networks. The operation of the protocol is such as to avoid the need for global synchronization required by TDM-based wavelength-routed networks.

Ion-implantation and analysis for doped silicon slot waveguides

Directory of Open Access Journals (Sweden)

McCallum J. C.

2012-10-01

Full Text Available We have utilised ion implantation to fabricate silicon nanocrystal sensitised erbium-doped slot waveguide structures in a Si/SiO2/Si layered configuration and photoluminescence (PL and Rutherford backscattering spectrometry (RBS to analyse these structures. Slot waveguide structures in which light is confined to a nanometre-scale low-index region between two high-index regions potentially offer significant advantages for realisation of electrically-pumped Si devices with optical gain and possibly quantum optical devices. We are currently investigating an alternative pathway in which high quality thermal oxides are grown on silicon and ion implantation is used to introduce the Er and Si-ncs into the SiO2 layer. This approach provides considerable control over the Er and Si-nc concentrations and depth profiles which is important for exploring the available parameter space and developing optimised structures. RBS is well-suited to compositional analysis of these layered structures. To improve the depth sensitivity we have used a 1 MeV α beam and results indicate that a layered silicon-Er:SiO2/silicon structure has been fabricated as desired. In this paper structural results will be compared to Er photoluminescence profiles for samples processed under a range of conditions.

Excitation of spin waves in BiFeO3 multiferroic film by the slot line transducer

Science.gov (United States)

Korneev, V. I.; Popkov, A. F.; Solov'yov, S. V.

2018-01-01

Analysis of the efficiency of magnetoelectric excitation of spin-waves in BiFeO3 multiferroic films by a slot line is performed based on the solution of dynamic Ginzburg-Landau equations for the antiferromagnetic vector. The excitation efficiency is determined by the magnitude of the conversion coefficient of the electromagnetic wave to the spin wave by the slot line transducer or in other words, losses on conversion in the slot line. Calculations are made for a homogeneous antiferromagnetic state of the multiferroic in the presence of a sufficiently large magnetic field and for a spatially modulated spin state (SMSS) at zero magnetic field. It is shown that in the case of a homogeneous antiferromagnetic state, the losses on the excitation of spin waves exceed the excitation efficiency in the SMSS state; however, as the frequency approaches the spin excitation gap, it falls and becomes lower than in the SMSS state. Spin wave excitation in the presence of antiferromagnetic cycloid strongly depends on the relation of the slot width of the transducer to the cycloid periodicity and on the magnitude of the shift of the position of the transducer along the cycloid on its period. The usage of multiferroics for delay lines in the considered frequency range from 100 to 600 GHz requires significant reduction in conversion and propagation losses. More promising seems multiferroic usage in phase shifters and switches for this range.

A quantitative AFM analysis of nano-scale surface roughness in various orthodontic brackets.

Science.gov (United States)

Lee, Gi-Ja; Park, Ki-Ho; Park, Young-Guk; Park, Hun-Kuk

2010-10-01

In orthodontics, the surface roughnesses of orthodontic archwire and brackets affect the effectiveness of arch-guided tooth movement, corrosion behavior, and the aesthetics of orthodontic components. Atomic force microscopy (AFM) measurements were used to provide quantitative information on the surface roughness of the orthodontic material. In this study, the changes in surface roughness of various orthodontic bracket slots before and after sliding movement of archwire in vitro and in vivo were observed through the utilization of AFM. Firstly, we characterized the surface of four types of brackets slots as follows: conventional stainless steel (Succes), conventional ceramic (Perfect), self-ligating stainless steel (Damon) and self-ligating ceramic (Clippy-C) brackets. Succes) and Damon brackets showed relatively smooth surfaces, while Perfect had the roughest surface among the four types of brackets used. Secondly, after in vitro sliding test with beta titanium wire in two conventional brackets (Succes and Perfect), there were significant increases in only stainless steel bracket, Succes. Thirdly, after clinical orthodontic treatment for a maximum of 2 years, the self-ligating stainless steel bracket, Damon, showed a significant increase in surface roughness. But self-ligating ceramic brackets, Clippy-C, represented less significant changes in roughness parameters than self-ligating stainless steel ones. Based on the results of the AFM measurements, it is suggested that the self-ligating ceramic bracket has great possibility to exhibit less friction and better biocompatibility than the other tested brackets. This implies that these bracket slots will aid in the effectiveness of arch-guided tooth movement.

Physical properties of new collimator cone system for stereotactic radiation therapy developed in samsung medical center.

Science.gov (United States)

Kim, D Y; Ahn, Y C; Oh, D G; Choi, D R; Ju, S G; Yeo, I H; Huh, S J

2000-09-01

A new collimator cone system has been developed at the Samsung Medical Center that overcomes some of the limitations of present commercially supplied collimator cones. The physical properties of the newly developed cone system are described in this report. The new cones have relatively larger aperture sizes (3.0-7.0 cm in diameter) and are 16 cm in length. Each new cone is fabricated with cerrobend alloy melted and poured into a stainless steel housing that is permanently fixed to a mounting plate. The mounting plate of the new cone is designed to insert into the wedge mount slot of the gantry head. The mechanical accuracy of the central axis of the cone pointing to the isocenter was tested using film, a steel ball positioned at the isocenter by the mechanical isocenter device. For the evaluation of beam flatness and penumbra, off-axis ratios at 5 cm depth were measured by film dosimetry using polystyrene phantom. The average error of the mechanical isocenter was 0.27 mm (+/- 0.16 mm). The beam flatness was excellent in the central region of the beam, and the average penumbra width was 3.35 mm (+/- 0.25 mm). The new cone design has more clearance between the patient's head and the gantry, and can more easily be removed from the gantry head because it slides in and out of the wedge slot. This facilitates changing cone sizes during one treatment session, and makes the process of double exposure port films easier. A new collimator cone system for stereotactic radiation therapy has been developed. The mechanical accuracy and physical properties are satisfactory for clinical use, and the new design permits a wider range of clinical applications for stereotactic radiation therapy.

Engineered SOI slot waveguide ring resonator V-shape resonance combs for refraction index sensing up to 1300nm/RIU (Conference Presentation)

Science.gov (United States)

Zhang, Weiwei; Serna, Samuel; Le Roux, Xavier; Vivien, Laurent; Cassan, Eric

2016-05-01

Bio-detection based on CMOS technology boosts the miniaturization of detection systems and the success on highly efficient, robust, accurate, and low coast Lab-on-Chip detection schemes. Such on chip detection technologies have covered healthy related harmful gases, bio-chemical analytes, genetic micro RNA, etc. Their monitoring accuracy is mainly qualified in terms of sensitivity and limit of the detection (LOD) of the detection system. In this context, recently developed silicon on insulator (SOI) optical devices have displayed highly performant detection abilities that LOD could go beyond 10-8RIU and sensitivity could exceeds 103nm/RIU. The SOI integrated optical sensing devices include strip/slotted waveguide consisting in structures like Mach-Zehnder interferometers (MZI), ring resonators (RR), nano cavities, etc. Typically, hollow core RR and nano-cavities could exhibit higher sensitivity due to their optical mode confinement properties with a partial localization of the electric field in low index sensing regions than devices based on evanescent field tails outside of the optical cores. Furthermore, they also provide larger sensing areas for surface functionalization to reach higher sensitivities and lower LODs. The state of art of hollow core devices, either based on Bragg gratings formed from a slot waveguide cavity or photonic crystal slot cavities, show sensitivities (S) up to 400nm/RIU and Figure of Merit (FOM) around 3,000 in water environment, FOM being defined as the inverse of LOD and precisely as FOM=SQ/λ, with λ the resonance wavelength and Q the quality factor of the considered resonator. Such high achieved FOMs in nano cavities are mainly due to their large Q factors around 15,000. While for mostly used RR, which do not require particular design strategies, relatively low Q factors around 1800 in water are met and moderate sensitivities about 300nm/RIU are found. In this work, we present here a novel slot ring resonator design to make

Isogloss: language and legacy on Mount St. Helens

Science.gov (United States)

E. Dodd

2012-01-01

Nothing standing aboveground today was here thirty years ago. The ground itself wasn't here. Oh, there was ground, but much of it lay below the surface where my boot soles slip a little in the loose pebbles of pumice. Rolling on loose rock and big ideas, for a moment I lose my sense of balance, glancing first at the sky above, then at the nearby peak of Mount St...

The permanent process

DEFF Research Database (Denmark)

Møller, Jesper; McCullagh, Peter

We extend the boson process first to a large class of Cox processes and second an even larger class of infinitely divisible point processes. Density and moment results are studied in detail. These results are obtained in closed form as weighted permanents, so the extension is called a permanent...... process. Temporal extensions and a particularly tractable case of the permanent process are also studied. Extensions of the ferminon process along similar lines, leading to so-called determinant processes, are discussed at the end. While the permanent process is attractive, the determinant process...

Design of a compact and integrated TM-rotated/TE-through polarization beam splitter for silicon-based slot waveguides.

Science.gov (United States)

Xu, Yin; Xiao, Jinbiao

2016-01-20

A compact and integrated TM-rotated/TE-through polarization beam splitter for silicon-based slot waveguides is proposed and characterized. For the input TM mode, it is first transferred into the cross strip waveguide using a tapered directional coupler (DC), and then efficiently rotated to the corresponding TE mode using an L-shaped bending polarization rotator (PR). Finally, the TE mode for slot waveguide at the output end is obtained with the help of a strip-to-slot mode converter. By contrast, for the input TE mode, it almost passes through the slot waveguide directly and outputs at the bar end with nearly neglected coupling due to a large mode mismatch. Moreover, an additional S-bend connecting the tapered DC and bending PR is used to enhance the performance. Results show that a total device length of 19.6 μm is achieved, where the crosstalk (CT) and polarization conversion loss are, respectively -26.09 and 0.54 dB, for the TM mode, and the CT and insertion loss are, respectively, -22.21 and 0.41 dB, for the TE mode, both at 1.55 μm. The optical bandwidth is approximately 50 nm with a CT<-20  dB. In addition, fabrication tolerances and field evolution are also presented.

Design and optical characterization of high-Q guided-resonance modes in the slot-graphite photonic crystal lattice.

Science.gov (United States)

Martínez, Luis Javier; Huang, Ningfeng; Ma, Jing; Lin, Chenxi; Jaquay, Eric; Povinelli, Michelle L

2013-12-16

A new photonic crystal structure is generated by using a regular graphite lattice as the base and adding a slot in the center of each unit cell to enhance field confinement. The theoretical Q factor in an ideal structure is over 4 × 10(5). The structure was fabricated on a silicon-on-insulator wafer and optically characterized by transmission spectroscopy. The resonance wavelength and quality factor were measured as a function of slot height. The measured trends show good agreement with simulation.

Polymer solar cell modules prepared using roll-to-roll methods: Knife-over-edge coating, slot-die coating and screen printing

DEFF Research Database (Denmark)

Krebs, Frederik C

2009-01-01

was patterned into stripes and juxtaposed with the ITO layer. The fourth layer comprised screen-printed or slot-die-coated PEDOT:PSS and the fifth and the final layer comprised a screen-printed or slot-die-coated silver electrode. The final module dimensions were 28 cm×32 cm and presented four individual solar...

CPW-fed Circularly Polarized Slot Antenna with Small Gap and Stick-shaped Shorted Strip for UHF FRID Readers

Science.gov (United States)

Pan, Chien-Yuan; Su, Chum-Chieh; Yang, Wei-Lin

2018-04-01

A new circularly polarized (CP) slot antenna with a small gap and a stick-shaped shorted strip is presented. The proposed antenna has a sufficient bandwidth for ultrahigh frequency (UHF) radio-frequency identification (RFID) reader applications. The antenna structure consists of a rectangular slot with a small gap, a stick-shaped shorted strip and a 50 Ω coplanar waveguide (CPW) feedline with an asymmetrical ground plane. By using the stick -shaped shorted strip to disturb magnetic current distribution on the slot, the CP radiation can be generated. The measured results demonstrate that the proposed antenna can reach a 10 dB return loss impedance bandwidth of 14.1 % (894-1030 MHz) and a 3 dB axial ratio (AR) bandwidth of 6.4 % (910-970 MHz). The whole antenna size is 80 × 80 × 1.6 mm3.

Brain cells in the avian 'prefrontal cortex' code for features of slot-machine-like gambling.

Directory of Open Access Journals (Sweden)

Damian Scarf

2011-01-01

Full Text Available Slot machines are the most common and addictive form of gambling. In the current study, we recorded from single neurons in the 'prefrontal cortex' of pigeons while they played a slot-machine-like task. We identified four categories of neurons that coded for different aspects of our slot-machine-like task. Reward-Proximity neurons showed a linear increase in activity as the opportunity for a reward drew near. I-Won neurons fired only when the fourth stimulus of a winning (four-of-a-kind combination was displayed. I-Lost neurons changed their firing rate at the presentation of the first nonidentical stimulus, that is, when it was apparent that no reward was forthcoming. Finally, Near-Miss neurons also changed their activity the moment it was recognized that a reward was no longer available, but more importantly, the activity level was related to whether the trial contained one, two, or three identical stimuli prior to the display of the nonidentical stimulus. These findings not only add to recent neurophysiological research employing simulated gambling paradigms, but also add to research addressing the functional correspondence between the avian NCL and primate PFC.

Influence of different rotor magnetic circuit structure on the performance of permanent magnet synchronous motor

Directory of Open Access Journals (Sweden)

Qiu Hongbo

2017-09-01

Full Text Available In order to compare the performance difference of the permanent magnet synchronous motors (PMSM with different rotor structure, two kinds of rotor magnetic circuit structure with surface-mounted radial excitation and tangential excitation are designed respectively. By comparing and analyzing the results, the difference of the motor performance was determined. Firstly, based on the finite element method (FEM, the motor electromagnetic field performance was studied, and the magnetic field distribution of the different magnetic circuit structure was obtained. The influence mechanism of the different magnetic circuit structure on the air gap flux density was obtained by using the Fourier theory. Secondly, the cogging torque, output torque and overload capacity of the PMSM with different rotor structure were studied. The effect mechanism of the different rotor structure on the motor output property difference was obtained. The motor prototype with two kinds of rotor structure was manufactured, and the experimental study was carried out. By comparing the experimental data and simulation data, the correctness of the research is verified. This paper lays a foundation for the research on the performance of the PMSM with different magnetic circuit structure.

Vapor-melt Ratio in Laser Fine Cutting of Slot Arrays

International Nuclear Information System (INIS)

Wang Xuyue; Meng Qingxuan; Kang Renke; Xu Wenji; Guo Dongming; Wang Lianji

2011-01-01

In order to improve cut quality for slot arrays, a new method of laser fine cutting under the consideration of the ratio of vapor to melt is presented. Laser cutting of 6063 aluminum alloy sheet, 0.5 mm in thickness, was carried out on a JK701H Nd:YAG pulse laser cutting system. The effects of vapor-melt ratio on kerf width, surface roughness and recast layer were studied which relate cutting qualities. Observation on the cut samples with different vapor-melt ratios (0.687, 1.574, 3.601 varied with laser power increasing, and 1.535, 3.601, 7.661 with decreasing of beam cutting speed) shows that high vapor-melt ratio improves laser cut quality clearly. Kerf width 0.2 mm of smooth area on kerf top area and thickness 2.03 μm of recast layer are obtained. No dross was found on the kerf bottom and the percentage of the smooth area is up to 40% out of whole kerf side. The research on vapor-melt ratio provides a deeper understanding of laser cutting and improves laser cut quality effectively.

A Design of Wide Band and Wide Beam Cavity-Backed Slot Antenna Array with Slant Polarization

Directory of Open Access Journals (Sweden)

Huiying Qi

2016-01-01

Full Text Available Design of antenna array under the limitation of restricted size is a challenging problem. Cavity-backed slot antenna is widely used because of its advantages of small size, wide band, and wide beam. In this paper, a design of wide band and wide beam cavity-backed slot antenna array with the slant polarization is proposed. To obtain wide band and wide beam with limited size, the inverted microstrip-fed cavity-backed slot antenna (IMF-CBSA is adopted as the element of 1 × 4 antenna array. The slant polarized antennas and their feeding networks are adopted because of their simple structures. The performance of the proposed antenna array is verified by the simulations and experiments. The measured VSWR < 2 bandwidth is 55% at the center frequency 21.8 GHz, and the gain is larger than 12.2 dB. Experimental results demonstrate that the proposed design achieves wide band and beam with the size of 68 mm × 56 mm × 14.5 mm.

Iodine-induced stress corrosion cracking of fixed deflection stressed slotted rings of Zircaloy fuel cladding

International Nuclear Information System (INIS)

Sejnoha, R.; Wood, J.C.

1978-01-01

Stress corrosion cracking of Zircaloy fuel cladding by fission products is thought to be an important mechanism influencing power ramping defects of water-reactor fuels. We have used the fixed-deflection stressed slotted-ring technique to demonstrate cracking. The results show both the sensitivity and limitations of the stressed slotted-ring method in determining the responses of tubing to stress corrosion cracking. They are interpreted in terms of stress relaxation behavior, both on a microscopic scale for hydrogen-induced stress-relief and on a macroscopic scale for stress-time characteristics. Analysis also takes account of nonuniform plastic deformation during loading and residual stress buildup on unloading. 27 refs

Design of novel SOI 1 × 4 optical power splitter using seven horizontally slotted waveguides

Science.gov (United States)

Katz, Oded; Malka, Dror

2017-07-01

In this paper, we demonstrate a compact silicon on insulator (SOI) 1 × 4 optical power splitter using seven horizontal slotted waveguides. Aluminum nitride (AIN) surrounded by silicon (Si) was used to confine the optical field in the slot region. All of the power analysis has been done in transverse magnetic (TM) polarization mode and a compact optical power splitter as short as 14.5 μm was demonstrated. The splitter was designed by using full vectorial beam propagation method (FV-BPM) simulations. Numerical investigations show that this device can work across the whole C-band (1530-1565 nm) with excess loss better than 0.23 dB.

Low Average Sidelobe Slot Array Antennas for Radiometer Applications

Science.gov (United States)

Rengarajan, Sembiam; Zawardzki, Mark S.; Hodges, Richard E.

2012-01-01

In radiometer applications, it is required to design antennas that meet low average sidelobe levels and low average return loss over a specified frequency bandwidth. It is a challenge to meet such specifications over a frequency range when one uses resonant elements such as waveguide feed slots. In addition to their inherent narrow frequency band performance, the problem is exacerbated due to modeling errors and manufacturing tolerances. There was a need to develop a design methodology to solve the problem. An iterative design procedure was developed by starting with an array architecture, lattice spacing, aperture distribution, waveguide dimensions, etc. The array was designed using Elliott s technique with appropriate values of the total slot conductance in each radiating waveguide, and the total resistance in each feed waveguide. Subsequently, the array performance was analyzed by the full wave method of moments solution to the pertinent integral equations. Monte Carlo simulations were also carried out to account for amplitude and phase errors introduced for the aperture distribution due to modeling errors as well as manufacturing tolerances. If the design margins for the average sidelobe level and the average return loss were not adequate, array architecture, lattice spacing, aperture distribution, and waveguide dimensions were varied in subsequent iterations. Once the design margins were found to be adequate, the iteration was stopped and a good design was achieved. A symmetric array architecture was found to meet the design specification with adequate margin. The specifications were near 40 dB for angular regions beyond 30 degrees from broadside. Separable Taylor distribution with nbar=4 and 35 dB sidelobe specification was chosen for each principal plane. A non-separable distribution obtained by the genetic algorithm was found to have similar characteristics. The element spacing was obtained to provide the required beamwidth and close to a null in the E

Radio-Frequency design of a Lower Hybrid Slotted Waveguide Antenna.

Czech Academy of Sciences Publication Activity Database

Helou, W.; Goniche, M.; Hillairet, J.; Žáček, František; Achard, J.; Adámek, Jiří; Bogár, Ondrej; Mollard, P.; Pascal, J.-Y.; Poli, S.; Šesták, David; Volpe, R.; Zajac, Jaromír

2017-01-01

Roč. 123, November (2017), s. 223-227 ISSN 0920-3796. [SOFT 2016: Symposium on Fusion Technology /29./. Prague, 05.09.2016-09.09.2016] Institutional support: RVO:61389021 Keywords : Lower Hybrid Current Drive * Slotted Waveguide Antenna * Phased arrays Subject RIV: JF - Nuclear Energetics OBOR OECD: Nuclear related engineering Impact factor: 1.319, year: 2016 https://www.sciencedirect.com/science/article/pii/S0920379617304076

Characterization of Engine Mount Elastomers

National Research Council Canada - National Science Library

Szabo, Jeffrey P

2005-01-01

As part of a project to develop methods for modelling the performance of engine mounts, several oil resistant alternative materials were prepared, and compared to conventional materials from mounts...

An analysis of switching and non-switching slot machine player behaviour.

Science.gov (United States)

Coates, Ewan; Blaszczynski, Alex

2013-12-01

Learning theory predicts that, given the repeated choice to bet between two concurrently available slot machines, gamblers will learn to bet more money on the machine with higher expected return (payback percentage) or higher win probability per spin (volatility). The purpose of this study was to investigate whether this occurs when the two machines vary orthogonally on payback percentage and volatility. The sample comprised 52 first year psychology students (mean age = 20.3 years, 20 females, 32 males) who had played a gaming machine at least once in the previous 12 months. Participants were administered a battery of questionnaires designed to assess level of knowledge on the characteristics and operation of poker machines, frequency of poker machine play in the past 12 months, personality traits of impulsivity and capacity for cognitive reflection, and gambling beliefs. For the experimental task, participants were instructed to play on two PC-simulated electronic gaming machines (EGMs or slot machines) that differed on payback percentage and volatility, with the option of freely switching between EGMs after a practice phase. Results indicated that participants were able to easily discriminate between machines and manifested a preference to play machines offering higher payback or volatility. These findings diverged from previous findings of no preference for play on higher payback/volatility machines, potentially due to of the current study's absence of the option to make multi-line and multi-credit bets. It was concluded that return rate parameters like payback percentage and volatility strongly influenced slot machine preference in the absence of betting options like multi-line bets, though more research is needed to determine the effects of such betting options on player distribution of money between multiple EGMs.

Process and device for the ultrasonic testing of slotted screws screwed into a head of a nuclear reactor fuel element for cracks