Quantitative Visualization of the Flow Within the Volute of a Centrifugal Pump. Part A: Technique

1992 ◽  
Vol 114 (3) ◽  
pp. 390-395 ◽  
Author(s):  
R. Dong ◽  
S. Chu ◽  
J. Katz
Keyword(s):  
Centrifugal Pump ◽  
Particle Concentration ◽  
Mean Shift ◽  
Pulsed Laser ◽  
Particle Displacement ◽  
Quantitative Visualization ◽  
The Mean ◽  
Visualization Experiments ◽  
Neutrally Buoyant ◽  
Quantitative Flow Visualization

This paper describes a series of quantitative flow visualization experiments within the volute of a centrifugal pump by implementing the “Particle Displacement Velocimetry” method (PDV or PIV). Part A focuses on the measurement procedures and includes an uncertainty analysis. This technique involves illuminating sections of a flow field with pulsed laser sheets while seeding the water with microscopic, neutrally buoyant particles containing imbedded fluorescent dye. By pulsing the laser more than once while recording a single photograph each particle leaves multiple traces on the same film. The analysis procedures consist of dividing the image to a large number of small sections (windows) and computing of the mean shift of all particles within each window. This shift is determined by computing the autocorrelation function of the image within the window. Digital image processing and specially written software are being utilized while analyzing the data. It is demonstrated that by controlling the magnification and particle concentration, the relative error can be maintained at about 1 percent. A sample analyzed image is presented. The rest of the data are included in Part B.

Quantitative Visualization of the Flow Within the Volute of a Centrifugal Pump. Part B: Results and Analysis

1992 ◽  
Vol 114 (3) ◽  
pp. 396-403 ◽  
Author(s):  
R. Dong ◽  
S. Chu ◽  
J. Katz
Keyword(s):  
Angular Momentum ◽  
Kinetic Energy ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Momentum Flux ◽  
Inflow Rate ◽  
Impeller Blade ◽  
Velocity Fluctuations ◽  
Quantitative Visualization ◽  
The Mean

PDV is used for measuring the velocity within the volute of a centrifugal pump at different impeller blade orientations, on and off design conditions. It is demonstrated that the flow is “pulsating” and depends on the location of the blade relative to the tongue. The leakage also depends on blade orientation and increases with decreasing flow rate. The velocity near the impeller is dominated by the jet/wake phenomenon. Differences in the outflux from the impeller, resulting from changes inflow rate, occur primarily near the exit. Away from the tongue the distributions of vθ mostly agrees with the assumption that vθ ∝ 1/r. Sites prone to high velocity fluctuations include the blade wake, interface between the jet and the wake and near the tongue. Angular momentum and kinetic energy fluxes, turbulent stresses and tubulence production are also computed. It is shown that at the same θ the momentum flux can increase near the impeller and decrease at the perimeter. Consequently, the mean flux cannot be used for estimating conditions near the impeller. Torques caused by τrθ and τθθ can be as high as 2 and 5 percent of the change in angular momentum flux, respectively.

The mean shift algorithm and its relation to kernel regression

2016 ◽  
Vol 348 ◽  
pp. 198-208 ◽  
Author(s):  
Youness Aliyari Ghassabeh ◽  
Frank Rudzicz
Keyword(s):  
Mean Shift ◽  
Kernel Regression ◽  
Mean Shift Algorithm ◽  
The Mean

scholarly journals A Novel Method for the Separation of Overlapping Pollen Species for Automated Detection and Classification

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Santiago Tello-Mijares ◽  
Francisco Flores
Keyword(s):  
Multilayer Perceptron ◽  
Cross Validation ◽  
Mean Shift ◽  
Automated Detection ◽  
Automated Identification ◽  
Fibonacci Series ◽  
Microscopic Images ◽  
Pollen Species ◽  
Novel Method ◽  
The Mean

The identification of pollen in an automated way will accelerate different tasks and applications of palynology to aid in, among others, climate change studies, medical allergies calendar, and forensic science. The aim of this paper is to develop a system that automatically captures a hundred microscopic images of pollen and classifies them into the 12 different species from Lagunera Region, Mexico. Many times, the pollen is overlapping on the microscopic images, which increases the difficulty for its automated identification and classification. This paper focuses on a method to segment the overlapping pollen. First, the proposed method segments the overlapping pollen. Second, the method separates the pollen based on the mean shift process (100% segmentation) and erosion by H-minima based on the Fibonacci series. Thus, pollen is characterized by its shape, color, and texture for training and evaluating the performance of three classification techniques: random tree forest, multilayer perceptron, and Bayes net. Using the newly developed system, we obtained segmentation results of 100% and classification on top of 96.2% and 96.1% in recall and precision using multilayer perceptron in twofold cross validation.

The mean shift method of chaotic sequences in the study of compressive sensing

2016 ◽  
Vol 8 (5) ◽  
pp. 1643-1654 ◽  
Author(s):  
Guoming Chen ◽  
Qiang Chen ◽  
Shun Long ◽  
Weiheng Zhu
Keyword(s):  
Compressive Sensing ◽  
Mean Shift ◽  
Shift Method ◽  
Chaotic Sequences ◽  
The Mean

scholarly journals Hydrodynamic diffusion of a sphere sedimenting through a dilute suspension of neutrally buoyant spheres

1992 ◽  
Vol 236 ◽  
pp. 513-533 ◽  
Author(s):  
Robert H. Davis ◽  
N. A. Hill
Keyword(s):  
Reasonable Agreement ◽  
Trajectory Analysis ◽  
Heavy Particle ◽  
Small Reynolds Number ◽  
Mean Velocity ◽  
Dilute Suspension ◽  
Explicit Formulae ◽  
The Mean ◽  
Neutrally Buoyant ◽  
Large Peclet Number

The motion of a heavy sphere sedimenting through a dilute background suspension of neutrally buoyant spheres is analysed for small Reynolds number and large Péclet number. For this particular problem, it is possible not only to calculate the mean velocity of the heavy particle, but also the variance of the velocity and the coefficient of hydrodynamic diffusivity. Pairwise, hydrodynamic interactions between the heavy sphere and the background sphere are considered exactly using volume integrals and a trajectory analysis. Explicit formulae are given for the two limiting cases when the radius of the heavy sphere is much greater and much less than that of the background spheres, and numerical results are given for moderate size ratios. The mean velocity is relatively insensitive to the ratio of the radius of the background spheres to that of the heavy sphere, unless this ratio is very large, whereas the hydrodynamic diffusivity increases rapidly as the radius ratio is increased. The predictions are in reasonable agreement with the results of falling-ball rheometry experiments.

scholarly journals Effect of the summer monsoon on aerosols at two measurement stations in Northern India – Part 2: Physical and optical properties

2011 ◽  
Vol 11 (1) ◽  
pp. 1749-1775 ◽  
Author(s):  
A.-P. Hyvärinen ◽  
T. Raatikainen ◽  
M. Komppula ◽  
T. Mielonen ◽  
A.-M. Sundström ◽  
...  
Keyword(s):  
Optical Properties ◽  
Particle Concentration ◽  
Monsoon Season ◽  
Single Scattering ◽  
New Delhi ◽  
Particle Volume ◽  
Seasonal Behavior ◽  
Northern India ◽  
Surface Measurements ◽  
The Mean

Abstract. Aerosol physical and optical properties were measured at two locations in Northern India during 2006–2010. The first measurement station was a background site in Mukteshwar, about 350 km northeast of New Delhi, in the foothills of the Indian Himalayas. The second measurement site was located in Gual Pahari, about 25 km south of New Delhi. At both stations, the average aerosol concentrations during the monsoon were decreased by 40–75% compared to the pre-monsoon average concentrations. The decrease varied with the total local rainfall. Also the mean aerosol size decreased during the monsoon season. The size distribution at Mukteshwar was unimodal, with a mode diameter at about 80 nm. In Gual Pahari, the ratio of Aitken and accumulation particle concentration was >1, due to wet deposition and new particle formation during the monsoon season. Aerosol concentrations during the early monsoon were found to be affected by mineral dust which in Gual Pahari was observed as an increased particle volume at around 3–4 μm. The single scattering albedo varied from 0.73 to 0.93 during the monsoon season, being slightly lower in Gual Pahari than in Mukteshwar. The aerosol columnar properties, which were measured in Gual Pahari, showed a somewhat different seasonal behavior compared to the surface measurements, with the aerosol optical depth increasing to an annual maximum in the early monsoon season.

scholarly journals Sediment Profile Imaging: Laboratory Study Into the Sediment Smearing Effect of a Penetrating Plate

2021 ◽  
Vol 8 ◽  
Author(s):  
Annabell Moser ◽  
Iain Pheasant ◽  
William N. MacPherson ◽  
Bhavani E. Narayanaswamy ◽  
Andrew K. Sweetman
Keyword(s):  
Flat Plate ◽  
Oil And Gas ◽  
Anthropogenic Impacts ◽  
Fine Sand ◽  
Sediment Type ◽  
Particle Displacement ◽  
Fish Farms ◽  
Sediment Volume ◽  
The Mean ◽  
Sand Sediments

Sediment profiling imaging (SPI) is a versatile and widely used method to visually assess the quality of seafloor habitats (e.g., around fish farms and oil and gas rigs) and has been developed and used by both academics and consultancy companies over the last 50 years. Previous research has shown that inserting the flat viewport of an SPI camera into the sediment can have an impact on particle displacement pushing oxygenated surface sediments to deeper sediment depths and making anthropogenically-disturbed sediment appear healthier than they may actually be. To investigate the particle displacement that occurs when a flat plate is inserted into seafloor sediments, a testing device, termed the SPI purpose-built sediment chamber (SPI-PUSH) was designed and used in a series of experiments to quantify smearing where luminophores were used to demonstrate the extent of particle displacement caused by a flat plate being pushed into the sediment. Here, we show that the plate of the SPI-PUSH caused significant smearing, which varied with sediment type and the luminophore grain size. The mean particle smearing measured directly behind the inserted plate was 2.9 ± 1.5 cm for mud sediments with sand-like luminophores, 4.3 ± 2.5 cm for fine sand sediments with sand-like luminophores and 1.9 ± 1.1 cm for medium sand sediments with mud-like luminophores. When the mean depth of particle smearing was averaged over a larger sediment volume (11 cm3) next to the inserted plate, substantial differences were seen between the plate-insertion experiments and controls highlighting the potential extent of smearing artefacts that may be produced when a SPI camera penetrates the seafloor. This experimental data shows that future studies using the SPI camera, or any other periscope-like device (e.g., planar optodes) need to acknowledge that smearing may be significant. Furthermore, it highlights that a correction factor may need to be applied to these data (e.g., the depth of apparent redox potential discontinuity layer) to correctly interpret SPI camera images and better determine the effect of anthropogenic impacts on seafloor habitats.

Dynamic Determination of Histogram Resolution for Object Tracking using the Mean-Shift Tracking Algorithm

2011 ◽  
Author(s):  
Takayuki Nishimori ◽  
Toyohiro Hayashi ◽  
Shuichi Enokida ◽  
Toshiaki Ejima
Keyword(s):  
Object Tracking ◽  
Mean Shift ◽  
Tracking Algorithm ◽  
The Mean

Tracking algorithm of snowboard target in intelligent system

2020 ◽  
pp. 1-9
Author(s):  
Zhipeng Li ◽  
Xiaolan Li ◽  
Ming Shi ◽  
Wenli Song ◽  
Guowei Zhao ◽  
...  
Keyword(s):  
Target Tracking ◽  
High Speed ◽  
Intelligent System ◽  
Mean Shift ◽  
Target Position ◽  
Tracking Algorithm ◽  
Tracking Accuracy ◽  
Mean Shift Algorithm ◽  
Target Track ◽  
The Mean

Snowboarding is a kind of sport that takes snowboarding as a tool, swivels and glides rapidly on the specified slope line, and completes all kinds of difficult actions in the air. Because the sport is in the state of high-speed movement, it is difficult to direct guidance during the sport, which is not conducive to athletes to find problems and correct them, so it is necessary to track the target track of snowboarding. The target tracking algorithm is the main solution to this task, but there are many problems in the existing target tracking algorithm that have not been solved, especially the target tracking accuracy in complex scenes is insufficient. Therefore, based on the advantages of the mean shift algorithm and Kalman algorithm, this paper proposes a better tracking algorithm for snowboard moving targets. In the method designed in this paper, in order to solve the problem, a multi-algorithm fusion target tracking algorithm is proposed. Firstly, the SIFT feature algorithm is used for rough matching to determine the fuzzy position of the target. Then, the good performance of the mean shift algorithm is used to further match the target position and determine the exact position of the target. Finally, the Kalman filtering algorithm is used to further improve the target tracking algorithm to solve the template trajectory prediction under occlusion and achieve the target trajectory tracking algorithm design of snowboarding.

Magnetite/Nickel andMagnetite/Cobalt Multilayer Nanostructures Obtained by Pulsed Laser Deposition

2003 ◽  
Vol 777 ◽  
Author(s):  
Monica Sorescu ◽  
Agnieszka Grabias ◽  
Lucian Diamandescu
Keyword(s):  
Pulsed Laser Deposition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
Multilayer Nanostructures ◽  
Mean Grain Size ◽  
Different Temperatures ◽  
The Mean ◽  
Metal Layers ◽  
Magnetite Phase

AbstractNanostructured magnetite/T multilayers, with T = Ni, Co, Cr, have been prepared by pulsed laser deposition. The thickness of individual magnetite and metal layers takes values in the range of 5 - 40 nm with a total multilayer thickness of 100 -120 nm. X-ray diffraction has been used to study the phase characteristics as a function of thermal treatment up to 550 °C. Small amounts of maghemite and hematite were identified together with prevailing magnetite phase after treatments at different temperatures. The mean grain size of magnetite phase increases with temperature from 12 nm at room temperature to 54 nm at 550 °C. The thermal behavior of magnetite in multilayers in comparison with powder magnetite is discussed.

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