Bar Width Research Articles

Cuckoo Search Algorithm for Multi-Objective Optimization of Transient Starting Characteristics of a Self-Starting HVPMSM

The starting and synchronization process of high-voltage permanent magnetic synchronous motors (HVPMSM) is a complex electromechanical transient problem. This paper proposes a multi-objective five-dimensional optimization method for starting characteristics of HVPMSM based on quadratic response surface models (QRSM) combined with Cuckoo search algorithm. Eighty-nine sets of transient finite element models were developed. To obtain starting current, starting time, starting torque and torque ripple, the transient process of HVPMSM is calculated with different cage bar width, cage bar depth, cage bar conductivity, and slot wedge conductivity. Steady-state and locked rotor experiments are conducted to verify the accuracy of the FEA. Then, the Cuckoo search method is employed to optimize design parameters achieved by the finite element models to obtain the minimum starting current, the maximum starting torque, the shortest starting time, and the minimum torque ripple, while maintaining high output performance and low cost. The results demonstrate that QRSM combined with Cuckoo search algorithm accurately describe the non-linear relationship between the structural characteristics, material properties and output performance of the HVPMSM. The best solutions are consistent with the results of the finite element analysis. In addition, the theoretical method is verified by experiments.

An Analysis of the Optical System of a Length Measurement Comparator

In the paper, the optical system of a precise bar length measuring comparator is analysed. The requirements for such a system are determined and systematized. The impact of the resolution, signal discretization frequency, image blurring, bar edge measurement indeterminacy and camera noise on measuring the bar width and establishing the bar position is discussed upon. Various algorithms have been analysed and finally a bar edge identification algorithm oriented to the scale calibration accuracy and the high processing speed was proposed. In the end of the paper, conclusions are provided.

Cathodoluminescence of ZnO Films on a Rhombohedral Plane of Sapphire with a Gold Buffer Layer

We have studied the luminescent properties of zinc oxide (ZnO) films on a rhombohedral plane of sapphire with a buffer layer of gold nanoislands. The luminescence spectrum revealed a set of oscillations caused by the classical interference in the thin ZnO film. This set can be represented by a bar code in which every bar corresponds to the oscillation line wavelength and the bar width corresponds to the line intensity. The high reproducibility and simplicity of manufacturing these thin-film ZnO structures and the high sensitivity of interference phenomena in these structures with respect to environment imply that their application as elements in various chemo- and biosensors holds promise.

Electrically induced breakdown of the quantum Hall effect at different Hall bar widths: Visualizing the edge- and bulk-dominated regimes within a quantum Hall plateau

We present systematic investigations of the electrically induced breakdown of the integer quantum Hall effect (QHE) in (Al,Ga)As-based Hall bars of different widths ranging from 7 to 70 $\ensuremath{\mu}\mathrm{m}$. It is striking that, for the narrow Hall bars, the threshold values for the applied voltage that induces the breakdown of the longitudinal zero-resistance state differ appreciably between the upper and lower sides of a quantum Hall (QH) plateau. When moving from the low magnetic field side of the QH plateau to higher magnetic fields, the threshold rises in a strongly superlinear manner until---at the expected integer value for the Landau level (LL) filling factor in the bulk of the two-dimensional electron system (2DES)---the threshold value abruptly drops to low values for the rest of the plateau. With increasing widths of the Hall bars, the zero-resistance state extends slightly further to higher magnetic field values. The threshold values on the low-magnetic field side are almost independent of the Hall bar width, whereas the threshold values on the high magnetic field side scale linearly with the Hall bar width. These observations correspond perfectly with the microscope picture of the QHE where the biased current flows in a dissipationless manner in electrically incompressible regions of the 2DES of locally the same LL filling factor, driven by the respective drop of the Hall voltage over the width of these incompressible regions. Owing to the self-consistent evolution of the electrically incompressible/compressible landscape within the 2DES as a function of magnetic field, a transition from an edge- to a bulk-dominated QH regime is described within a QH plateau. This microscopic picture was derived from sophisticated, long-lasting scanning probe experiments measuring Hall potential profiles on typically 15-$\ensuremath{\mu}$m-wide Hall bars. Conversely, performing systematic electrically induced breakdown measurements like those presented here would allow us to identify the presence of edge- and bulk-dominated regimes of the QHE in a wider variety of samples.

Automated phantom analysis for gamma cameras and SPECT: A methodology for use in a clinical setting.

PurposeWe introduce an automated, quantitative image analysis package for gamma camera and single photon emission computed tomography quality control. Our focus was to produce consistent methods that are feasible in clinical settings and use standard phantoms.MethodsFour gamma cameras were used to acquire planar images of four‐quadrant bar phantoms and projection views of an American College of Radiology (ACR) phantom as part of a standard gamma camera quality control program. Images were sent to QC‐Track® (Atirix Medical Systems, Inc., Minneapolis, MN, USA), which automatically placed predetermined regions of interest (ROIs) and performed analysis. For the bar phantom, a standard deviation (SD)‐based modulation transfer function was calculated for a circular ROI in each quadrant. The bar widths at various MTF values were reported using linear interpolation as applicable. For the ACR phantom, the contrast‐to‐noise ratio (CNR) for each sphere, a modulation for each rods section, and a percent deviation for uniformity ROIs was calculated. Spheres corresponding to a CNR of 3, and the rod size at various modulations were also reported using linear interpolation. Visual analysis was performed by three medical physicists to evaluate interobserver variability and correlation to quantitative values.ResultsAnalysis of the bar phantom showed predictable differences with changes in matrix size and bar width and showed consistency over similar acquisitions over the course of the study. Analysis of the ACR Phantom showed increasing CNR and modulation with increasing sphere and rod diameter, as expected. For both phantoms, quantitative values from linear interpolation correlated well with visual analysis.ConclusionOur automated method for quantitative image analysis is consistent and shows increased precision and sensitivity when compared to standard visual methods. Thresholds correspond well with visual analysis and previous guidelines for observer visibility (e.g., Rose criterion), making our framework suitable for routine use in a nuclear medicine department.

Revisiting electrical performance measurement scheme of industrial crystalline silicon wafer solar cells

Variation in electrical performance measurement of industrial crystalline Si (c-Si) solar cells is commonly observed. The probable reasons include non-uniform illumination, spectral mismatch, shadow due to dissimilar probing bars and probing schemes incompatible to cell front metal contact design. In the present work, we have studied the impact of shadow of probing bars on the I-V measurement of Al-BSF c-Si test solar cell. The shadow created due to fixed width of probe bars (PB) reduce the current generation along the contact bus bars (BB). A correction factor is devised for shadow loss in short circuit current of the test cell and applied in the I-V measurements. Additionally, we observed the variation in correction factor due to the difference in BB and PB width resulted in the difference in power loss even contacting using the same bus bars. In conclusion, we have successfully applied shadow correction in our I-V testing facility (B) and reduced the magnitude of variation from 2.75% to 0.25% in solar cell performance when compared with other testing facility (A).

Geometric Characterization of Fluvial Associated Braid Bar Deposits in the Niger Delta

Remote sensing and GIS based results from the geometric characterization of braid bar deposits in the Niger Delta are presented in this work. In this study the geometry of 67- braid bar deposits from Landsat images of 1985 and 2015 were documented and compared to determine the relationship that exist between geometric dimensions and the amount of change that has occurred on them. The braid bars identified in this work are all associated with fluvial environment in the Niger Delta. Braid bars in 1985 are observed to be greater in length, width and area than those in 2015. R² values (0.6) indicate that a significant relationship exists between braid bar length and width. R² values also indicate a significant relationship exists between both length and area (0.7) and width and area (0.8) of the braid bars values within the study area. Thus, the utilization of width to predict the length and vice versa of braid bars is reasonable. Hence data from this study provides relevant information on size ranges that can be utilized for the efficient characterization, modelling and development of hydrocarbon reservoirs.

Scapulocoracoid morphology in the skates of the tribe Riorajini (Elasmobranchii, Rajiformes, Arhynchobatidae)

The scapulocoracoid morphology in batoids has been investigated by previous authors but descriptions and illustrations of its ventral surface are lacking for Riorajini species. Here, we describe and illustrate the lateral and ventral views of the scapulocoracoid in females and males of Rioraja agassizi and Atlantoraja species, and six new measurements are proposed. In adult females, the distance between procondyles, distance between metacondyles, width of the coracoid bar, distance between mesocondyle and metacondyle, and the first posterior ventral foramen width are proportionally wider than in males. In juveniles of the four species, differences between sexes regarding proportional dimensions are less conspicuous. The wider and long scapulocoracoid of females may provide more space and protection for the development of embryos but further investigation is needed. Given the influence of sexual dimorphism in proportional dimensions and morphology of the scapulocoracoid, characters associated to this structure need to be cautiously analyzed in future phylogenetic studies.

Detection of Simulated Tactile Gratings by Electro-Static Friction Show a Dependency on Bar Width for Blind and Sighted Observers, and Preliminary Neural Correlates in Sighted Observers.

The three-dimensional micro-structure of physical surfaces produces frictional forces that provide sensory cues about properties of felt surfaces such as roughness. This tactile information activates somatosensory cortices, and frontal and temporal brain regions. Recent advances in haptic-feedback technologies allow the simulation of surface micro-structures via electro-static friction to produce touch sensations on otherwise flat screens. These sensations may benefit those with visual impairment or blindness. The primary aim of the current study was to test blind and sighted participants’ perceptual sensitivity to simulated tactile gratings. A secondary aim was to explore which brain regions were involved in simulated touch to further understand the somatosensory brain network for touch. We used a haptic-feedback touchscreen which simulated tactile gratings using digitally manipulated electro-static friction. In Experiment 1, we compared blind and sighted participants’ ability to detect the gratings by touch alone as a function of their spatial frequency (bar width) and intensity. Both blind and sighted participants showed high sensitivity to detect simulated tactile gratings, and their tactile sensitivity functions showed both linear and quadratic dependency on spatial frequency. In Experiment 2, using functional magnetic resonance imaging, we conducted a preliminary investigation to explore whether brain activation to physical vibrations correlated with blindfolded (but sighted) participants’ performance with simulated tactile gratings outside the scanner. At the neural level, blindfolded (but sighted) participants’ detection performance correlated with brain activation in bi-lateral supplementary motor cortex, left frontal cortex and right occipital cortex. Taken together with previous studies, these results suggest that there are similar perceptual and neural mechanisms for real and simulated touch sensations.

Applying a rule-based object-based image analysis approach for nearshore bar identification and characterization

Nearshore bars are important coastal features that influence beach–dune dynamics and protect the coast from high-energy wave events. Historically, in situ methods were used to study beach–dune dynamics and nearshore bars. Video monitoring systems, such as Argus, have been the favored remote sensing approach for studying nearshore bars dynamics and evolution. These systems are costly to install and maintain, and a limited number of stations are available. Our study introduces a lower cost alternative to study these coastal features. A rule-based classification object-based image analysis approach is introduced to identify nearshore bars (and their characteristics, such as bar length, width, count, and distance from the wet/dry line) from very-high-resolution (VHR) multispectral imagery. Nearshore bars were successfully identified and characterized as single and multiple bar systems. Our study demonstrates that VHR satellite remote sensing is a viable alternative with comparative results to video monitoring systems. Their capability of acquiring high-resolution imagery in large spatial extent is superior in continuous observation and characterization of nearshore bars. The proposed approach provides information at a more relevant spatiotemporal scale at which these systems evolve, which is helpful to coastal scientists and managers.

Wasteful carotenoid coloration and its effects on territorial behavior in a cichlid fish

The famously diverse body coloration of cichlid fish serves communicative functions in mating and social interactions including competition for resources. Here, we examined the effects of a color pattern trait—the width of a yellow bar on a black body—on territorial competition in males and females of a color variant (“Ikola”) of the Lake Tanganyika cichlid Tropheus. First, measuring integumentary carotenoid concentrations in the yellow and black body regions, we established that wider yellow bars require more carotenoids allocated to body coloration. However, we also detected high carotenoid concentrations in the black body regions (> 100 µg/g fresh skin), raising questions about the function of non-displayed integumentary carotenoids. Behavioral experiments showed that fish with wider bars were quicker to explore an unfamiliar area of the tank. In experiments including presentations of fish dummies, the bar width of ‘territorial’ dummies had no effect on the latency time which test fish took to intrude into the dummies’ territories. However, male test fish performed fewer aggressive acts against wide-barred than against narrow-barred dummy competitors. Our results suggest that intimidation by wide bars as well as correlations between bar width and explorative behavior may contribute to mediating success in territorial Tropheus “Ikola”.

Selective generation of ultrasonic guided waves for damage detection in rectangular bars

Ultrasonic guided waves are used in non-destructive testing and structural health monitoring solutions for long-range inspection, in applications ranging from Civil Engineering to Aerospace. In order to ease the inspection process, it is generally preferable to generate a carefully selected single mode. Although single mode Lamb wave generation is not difficult to achieve in infinite plate-like structures, with carefully polarized or sized piezoceramic elements, for example, such selective generation is much more difficult in a rectangular bar. In this article, we consider the propagation along a thin plate of finite rectangular cross section, which corresponds to a rectangular bar. The finite lateral width leads to a greater density of modes compared to an infinite plate. The authors have previously addressed this matter and developed a methodology for the selective generation of modes in the harmonic regime. This article extends this methodology to selective mode generation for finite time excitation, such as bursts. Results are presented for single mode generation of A0,0 and A0,1 in an aluminum bar instrumented with eight piezoelectric transducers. The waveguide modal basis is calculated with the two-dimensional semi-analytical finite element method, and measurements are conducted using a three-dimensional laser-Doppler vibrometer. To illustrate the potential of the method for structural health monitoring purposes, the detection of a defect simulated by a pair of magnets placed at various positions over the bar width is demonstrated.

Coupling of quantum-well emission to waveguide–plasmon polaritons in rolled-up microtubes

We study the coupling of GaAs quantum wells to waveguide–plasmon polaritons supported by a thin InAlGaAs-based slab waveguide and a Ag grating. The hybrid photon–plasmon modes are excited in a freestanding emitter–waveguide–plasmon structure realized by rolling-up strained InAlGaAs-based layers and nanopatterned Ag structures. By varying the grating’s bar width, we tune the plasmonic resonance of the system. We observe by means of spatially, spectrally, and temporally resolved photoluminescence measurements, a coupling of the quantum-well emission to the waveguide–plasmon system for a specific grating’s bar width. Supported by finite-element simulations, we can assign the coupling to the excitation of a waveguide–plasmon polariton.

Delineator for Separated Bicycle Lanes at Sidewalk Level

The City and County of San Francisco sponsored research to identify a delineator for separated bicycle lanes at sidewalk level that is at least as detectable as truncated-dome detectable warning surface (DWS) by pedestrians with visual impairments, and that is not a barrier to pedestrians with mobility impairments. Tested as potential delineators were a 12-in. wide continuous raised trapezoid (0.75 in. high), and 12- and 24-in. wide installations of relatively wide flat-top bars (FTBs) and of a “corduroy” surface of narrower bars spaced more closely together (both 0.2 in. high). Thirty-one visually-impaired participants detected all five surfaces in addition to DWS, a total of six times each, from 90° and 25° approaches, with mean detection accuracies better than 90% for all surfaces (no significant differences). The long white cane intruded into the cycle track significantly less frequently with 24-in. wide surfaces. In a counterbalanced manner, participants also briefly stepped onto each surface eight times, each time identifying it as “domes,”“bars,” or “trapezoid.” They identified the trapezoid significantly better (mean rate of correct identification = 98.8%) than all other surfaces. A majority of participants with vision disabilities preferred the trapezoid. Thirty participants with a variety of mobility impairments, using a variety of aids, crossed each surface four times with little significant difference from the DWS in effort, instability, and discomfort or pain. No surface was found to be a barrier to crossing. The trapezoidal surface was recommended as the delineator, although the 24-in. FTBs also performed very well.

Short term crack width prediction of CFRP bars reinforced coral concrete

In order to study the crack development of CFRP reinforced coral concrete under different bending conditions, experimental study investigation of crack width of steel and CFRP reinforced coral concrete beams were performed. A comparative study of cracking rate, maximum crack height and crack patterns in CFRP bars reinforced coral concrete beams at different stages is made with ordinary steel reinforced coral concrete beams. The results show that under similar reinforcement ratio, the crack width and crack spacing of CFRP reinforced coral concrete beams are larger than that of steel reinforced concrete beams, increasing the reinforcement ratio of test beams can effectively reduce the crack width. The current deign formula from existing design codes overestimates the value of the relative bond characteristic coefficient (vi) and the strain inhomogeneity coefficient (ψ). Therefore, in this paper, the formula for maximum crack width of CFRP bars reinforced beams is developed based on the experimental data, the relative bond characteristic coefficient, the strain inhomogeneity coefficient of the longitudinal reinforcement, the ratio of the maximum crack width to the average crack width (τs) are included in the formula. The formula is validated with test results, the calculated value agrees well with the experimental results. Therefore, can be used for the future design.

Thermo–mechanical coupled analysis for tunnel lining with circular openings

Under heavy load condition, tunnel linings are often designed to be quite thick. This leads to the common temperature control problem of mass concrete, whereby cement hydration heat and uneven heat dissipation during concrete pouring can cause lining cracks. Currently, pouring concrete in different areas or increasing the heat dissipation measures in the concrete curing stage are the main measures to alleviate this problem. In this paper, a new type of longitudinal circular opening structure for tunnel linings is proposed. To meet the requirements of bearing capacity, this tunnel lining type can realize effective heat reduction and heat dissipation. Firstly, a field test is conducted to obtain the structural temperature and internal force to verify the rationality of the design. Then, the thermo–mechanical (TM) finite element method is employed to investigate the temperature variations, crack width, and internal force of the steel bar under different circular opening sizes. Meanwhile, the influence of the circular opening size on the heat dissipation performance and bearing capacity of the lining is presented, as well as a method for constructing an optimal circular lining size. The results show that cooling openings can decrease the peak temperature of concrete while simultaneously increasing the cooling efficiency early in the pouring stage. The lower and upper bounds of the circular opening are limited by thermally induced stress and tunnelling-induced stress, respectively. In this research, the reasonable hole size in a thick lining is proven to be effective and safe in the Longdongbao tunnel.

Sibling competition affects body condition and allostatic load in the colonial nesting lesser kestrel Falco naumanni

Sibling competition leading to physiological stress and elevated allostatic load is driven by asymmetrical development and limited resources. To investigate these predictions, we studied broods of the lesser kestrel Falco naumanni, from a nest-box population in Armenio, Central Greece. For each nestling reared in nest-boxes, we noted the age (in days) since hatching, measured the wing chord length and body mass. We also clipped the central right rectrix for ptilochronology for subsequent analysis in the laboratory. We measured 206 nestlings from 61 broods (range 2-5 nestlings). In the case of nestlings < 18 days old (n = 198, 96.1% of all) we also measured the length of feathers. As a measure of body condition, we used the residuals of the linear regression for the relationship between wing chord length and body mass, while the growth bar width of feathers was used as a second, independent index of body size and allostatic load. A GLMM and information-theory criterion showed that both measures of body condition decreased incrementally from the first sibling to the most subordinate in the brood. Body condition of subordinate siblings was influenced by the number of siblings in the nest; i.e. the larger the brood size the greater the discrepancy in body condition between siblings. At the same time, we did not find any influence of sex on either measure of fitness. Thus, our results indirectly support the hypothesis that sibling competition may cause physiological developmental stress which is reflected in decreased body condition and increased allostatic load for younger nestlings.

Performance analysis of ladder-secondary-linear induction motor with two different secondary types using Magnetic Equivalent Circuit

This paper proposes a Magnetic Equivalent Circuit (MEC) method to model the Ladder-Secondary-Linear Induction Machines (LS-LIMs), where the model accuracy can be determined as desired. This method makes it much easier to change parameters of motor include poles and slots number as well as its dimension than the Finite Element Method (FEM). The end-effect phenomenon is considered in the model by two virtual zones with arbitrary length at the both exit and entrance ends of the primary for saturable LS-LIMs. The proposed MEC method also makes it possible to investigate the motor performance under different secondary structures (two types), bars material and their width. Finally, FEM and experimental results are given to evaluate the accuracy of the proposed method, and simulation time is compared with 2D-FEM. In a general overview, modeling the end-effect and saturation phenomena, analyzing the impacts of different secondary structures and bars width on the performance of motor are studied by the suggested MEC method in the present work.

Analysing demands for the clear widths of lattice bars in horse husbandry

At bars, used in various places in horse husbandry, horses can hurt themselves when retracting their heads or hooves after pushing them through the interspaces. In order to reduce the risk of injury, the clear widths and material thicknesses of bars should be chosen so that horse heads and hooves either cannot pass between the spaces or can be retracted safely. However, research to date has not provided any reliable information on bar width (vertical and horizontal) that is safe for horses. Grid bar width used in practice and recommended in the literature is based on empirical values and technical material properties. In this study, heads and hooves of 480 horses (233 mares, 204 geldings and 43 stallions) of 23 breeds were measured for making statements about the suitability of standard bar width, when considering the anatomy of the horse. It turned out that for vertical bars, an interspace of no more than five centimetres can be considered to be safe for all horses of a height of 110 centimetres and an age of two years and more. With horizontal lattice bars, a clear width of exactly 17 centimetres proved to be safe. This applies to all horses of a height of 148 centimetres and an age of two years or more. The clear widths of panels must be considered critical for horse welfare. When horses, for example, try to eat outside the panels and put their head through the bars, they may get stuck.

A decadal‐scale numerical model for wandering, cobble‐bedded rivers subject to disturbance

AbstractAlluvial rivers are composed of self‐formed channels which are sensitive to disturbances in their flow and sediment‐supply regimes. Regime changes commonly occur over decadal and longer timescales and can be caused by anthropogenic alterations such as dam construction and removal. Advances in numerical modeling have increased our ability to explore geomorphic adjustments over long timescales; however, many models designed to be run for decades or longer assume that banks are immovable or that channel width is constant. Since river channels often respond to disturbance by adjusting their geometry, this is a significant shortcoming. To investigate the impact of long‐term sediment supply alterations on channel geometry and stability, we have adapted MAST‐1D, a reach‐scale bed evolution model, to incorporate functions for bank erosion, vegetation encroachment, and local avulsions. The model is designed for medium‐large, coarse multithreaded rivers and can be run over long (decades–centuries) timescales. Bank erosion is a function of the mobility and transport capacity for structurally‐important grains which protect the bank toe. Vegetation growth is proportional to point bar width and occurs during conditions of low shear stress. Local avulsions occur when aggradation causes channel depth to drop below a threshold. We apply the model to the Elwha River in Washington, USA with the goal of investigating if and when the river recovers from dam emplacement and removal. The Elwha was dammed for nearly 100 years, and then two dams were removed, releasing a large pulse of sediment. We have modeled the set of reaches between the two dams. Our simulations suggest that channel response to dam emplacement occurs gradually over several decades but that the channel recovers to near pre‐dam conditions within about a decade following the removal. The dams leave a lasting legacy on the floodplain, which does not completely recover, even after two centuries. © 2019 John Wiley &amp; Sons, Ltd.