scholarly journals An Infrared DoLP Model Considering the Radiation Coupling Effect

Photonics ◽  
2021 ◽  
Vol 8 (12) ◽  
pp. 546
Author(s):  
Dezhi Su ◽  
Liang Liu ◽  
Lingshun Liu ◽  
Ruilong Ming ◽  
Shiyong Wu ◽  
...  
Keyword(s):  
Coupling Effect ◽  
Sea Surface ◽  
Polarization Degree ◽  
Observation Angle ◽  
Minimum Value ◽  
Detection And Identification ◽  
Increasing Trend ◽  
Simulation Results ◽  
Aluminum Plates ◽  
Polarization Detection

The polarization degree of objects in the marine background are affected by infrared radiation from sea surface. Taking into account the radiation coupling effect (RCE), a degree of linear polarization (DoLP) model is deduced. The DoLP of painted aluminum plates at different observation angles are simulated. The simulation results show the trend of the DoLP of the object decreases first and then increases as the observation angle θO, with the minimum value at θO=53∘. Nevertheless, we get a monotonically increasing trend and the minimum value is at θO=0∘ without considering RCE. The experimental results accord closely with those of the simulation with RCE. This conclusion is useful for the polarization detection and identification of infrared objects in the marine background.

Induction motors broken rotor bars detection using RPVM and neural network

2019 ◽  
Vol 38 (2) ◽  
pp. 596-615 ◽  
Author(s):  
Saddam Bensaoucha ◽  
Sid Ahmed Bessedik ◽  
Aissa Ameur ◽  
Ali Teta
Keyword(s):  
Design Methodology ◽  
Induction Motors ◽  
Content Type ◽  
Broken Rotor Bars ◽  
Squirrel Cage ◽  
Detection And Identification ◽  
Squirrel Cage Induction Motor ◽  
Simulation Results ◽  
Cage Induction Motor ◽  
Diagnosis Technique

Purpose The purpose of this study aims to focus on the detection and identification of the broken rotor bars (BRBs) of a squirrel cage induction motor (SCIM). The presented diagnosis technique is based on artificial neural networks (NNs) that use as inputs the results of the spectral analysis using the fast Fourier transform (FFT) of the reduced Park’s vector modulus (RPVM), along with the load values in which the motor operates. Design/methodology/approach First, this paper presents a comparative study between FFT applied on Hilbert modulus, Park’s vector modulus and RPVM to extract feature frequencies of BRB faults. Moreover, the extracted features of FFT applied to RPVM and the load values were selected as NNs’ inputs for the detection of the number of BRBs. Findings The obtained simulation results using MATLAB (Matrix Laboratory) environment show the effectiveness and accuracy of the proposed NNs based approach. Originality/value The current paper presents a novel diagnostic method for BRBs’ fault detection in SCIM, based on the combination between the signal processing analysis (FFT of RPVM) and artificial intelligence (NNs).

The Effect of Gap Space on Flow Induced Motions of Two Square Cylinders in Tandem

2017 ◽  
Author(s):  
Haibo Wang ◽  
Qunfeng Zou ◽  
Li Zhang ◽  
Chunmei Wu ◽  
Lin Ding
Keyword(s):  
Reynolds Number ◽  
Elastic Support ◽  
Square Cylinder ◽  
Frequency Responses ◽  
Square Cylinders ◽  
Changing Trends ◽  
Increasing Trend ◽  
Simulation Results ◽  
Frequency Ratios ◽  
Center Distance

When the Reynolds number is in the range of 30,000 and 100,000, the vibration characteristics of two square cylinders with elastic support and different tandem spacing are investigated by 2-D URANS simulations using OpenFOAM. In this work, the center to center distance (d) of two square cylinders is an important parameter and it increases from 2 to 6 diameters (D). Amplitude responses and frequency responses of first and second square cylinders are discussed and compared. The amplitude and frequency responses of first square cylinder are verified by the experiment results of Nemes et al. and they agree well in changing trends. The simulation results indicate that the amplitudes of the two square cylinders with different tandem spacing show an increasing trend with reduced velocity increasing. The maximum amplitudes reach 1.06D and 1.10D for the first and the second cylinders, respectively. And the oscillation of the second square cylinder is enhanced when d = 4D. The center to center distance has no significant effect on the frequency ratios of two square cylinders.

The Factors Sensitivity Analysis of Drift Ice Impact Force on the Pier

2014 ◽  
Vol 852 ◽  
pp. 472-475
Author(s):  
Su Feng Zhang ◽  
Tian Lai Yu
Keyword(s):  
Impact Force ◽  
Nonlinear Finite Element ◽  
Bridge Piers ◽  
Element Analysis ◽  
Analysis Theory ◽  
Increasing Trend ◽  
Force Impact ◽  
Ice Strength ◽  
Simulation Results ◽  
The Impact

This paper base on the actual form and structure of the original bridge piers actual data, according to the exposure collision theory and nonlinear finite element analysis theory, using LS-DYNA software, research the realationship of drift ice strength, modulus of elasticity, thickness factors with affecting convection ice impact force, while the drift ice impact force impact of the bridge was tested and simulated contrast. Simulation results show that the impact force with the flow of ice floe strength, elastic modulus, the increase of the thickness of the ice sheet was an increasing trend.

scholarly journals Weak Tropical Cyclones Dominate the Poleward Migration of the Annual Mean Location of Lifetime Maximum Intensity of Northwest Pacific Tropical Cyclones since 1980

2017 ◽  
Vol 30 (17) ◽  
pp. 6873-6882 ◽  
Author(s):  
Ruifen Zhan ◽  
Yuqing Wang
Keyword(s):  
Tropical Cyclones ◽  
Large Scale ◽  
Surface Wind ◽  
Surface Wind Speed ◽  
Maximum Intensity ◽  
Sea Surface ◽  
Northwest Pacific ◽  
The Past ◽  
Increasing Trend ◽  
Sst Warming

The poleward migration of the annual mean location of tropical cyclone (TC) lifetime maximum intensity (LMI) has been identified in the major TC basins of the globe over the past 30 years, which is particularly robust over the western North Pacific (WNP). This study has revealed that this poleward migration consists mainly of weak TCs (with maximum sustained surface wind speed less than 33 m s−1) over the WNP. Results show that the location of LMI of weak TCs has migrated about 1° latitude poleward per decade since 1980, while such a trend is considerably smaller for intense TCs. This is found to be linked to a significant decreasing trend of TC genesis in the southern WNP and a significant increasing trend in the northwestern WNP over the past 30 years. It is shown that the greater sea surface temperature (SST) warming at higher latitudes associated with global warming and its associated changes in the large-scale circulation favor more TCs to form in the northern WNP and fewer but stronger TCs to form in the southern WNP.

THE EFFECT OF THE GAS INLET ON THE FLUID FIELD DURING FABRICATING HFCVD DIAMOND-COATED CUTTING TOOLS

2014 ◽  
Vol 21 (05) ◽  
pp. 1450068
Author(s):  
BIN SHEN ◽  
SULIN CHEN ◽  
LEI CHENG ◽  
FANGHONG SUN
Keyword(s):  
Initial Velocity ◽  
Coupling Effect ◽  
Cutting Tools ◽  
Chemical Vapor ◽  
Gas Velocity ◽  
Gas Field ◽  
Growth Environment ◽  
Fluid Field ◽  
Flute Surface ◽  
Simulation Results

In the present study, the fluid field in a process of fabricating diamond coated cutting tools using the hot filament chemical vapor deposition (HFCVD) method is investigated using the finite volume method (FVM), in which the effects of the inlet height, gas initial velocity, inlet radius and arrangement are illustrated in terms of the gas velocity magnitude and vector distribution near the filaments and the flute surface of cutting tools. In the simulations, the coupling effect of the temperature and the gas field is also considered by simultaneously calculating the temperature distribution. The simulation results suggest that either shortening the distance between the gas inlet and filaments, or increasing the gas initial velocity is helpful for the reactive gas arriving at filaments surface and being dissociated. Furthermore, increasing the inlet area is able to significantly increase the velocity of gas field around the filaments, as well as produce a much more uniform gas velocity field. Based on this conclusion, two novel multi-inlets setups are proposed to further improve the generated gas field and the simulation results show that the most superior gas field can be achieved with the one including 8 larger central inlets and 24 smaller outskirt inlets. Finally, an actual deposition experiment is carried out and its result indicates that adopting the optimized such inlet arrangement could generate a highly uniform and homogeneous growth environment on whole deposition area.

scholarly journals Evolution of primary production and its drivers on the Lebanese coast between 1986 and 2013

2020 ◽  
Vol 20 (4) ◽  
pp. 207-217
Author(s):  
Ali Fadel ◽  
Lama Salameh ◽  
Malak Kanj ◽  
Ahmad Kobaissi
Keyword(s):  
Primary Production ◽  
Phytoplankton Community ◽  
Controlling Factors ◽  
Sea Surface ◽  
Biogeochemical Model ◽  
Average Temperature ◽  
Biogeochemical Models ◽  
Increasing Trend ◽  
Production Dynamics ◽  
Lebanese Coast

AbstractPhysical-biogeochemical models help us to understand the dynamics and the controlling factors of primary production. In this study, the outputs of a validated hydrodynamic and biogeochemical model were used to elucidate the primary production dynamics between 1992 and 2012 for three studied sites on the Lebanese coast: Naqoura, Beirut, and Tripoli. The results showed that primary production presents a homogeneous spatial distribution along the Lebanese coastline. The phytoplankton community has a low optimal temperature. The thermocline develops in March, with maximum stratification in August and fades in October. Chlorophyll, dissolved oxygen and salinity were positively correlated throughout the water column. A significant increasing trend of sea surface temperature was found on the Lebanese coast over 27 years, between 1986 and 2013. Annual averages increased from 22°C in 1986 to 23.1°C in 2013 with the highest recorded average temperature of 23.7 °C in 2010.

scholarly journals DUAL-BAND RECONFIGURABLE MIMO ANTENNA FOR WIRELESS APPLICATIONS

2021 ◽  
Vol 25 (3) ◽  
pp. 1-9
Author(s):  
Abdullah A. Jabber ◽  
◽  
Raad H. Thaher ◽  
Keyword(s):  
Coupling Effect ◽  
Mimo System ◽  
Dual Band ◽  
Reconfigurable Antenna ◽  
Pin Diode ◽  
Wireless Devices ◽  
Resonant Frequencies ◽  
Mimo Antenna ◽  
Wireless Applications ◽  
Simulation Results

This article presents design and simulation of a new compact four-element dual-band MIMO frequency reconfigurable antenna that can be reconfigured for WiMAX and LTE applications. The antenna includes four elements at the same FR4 substrate with an optimized overall size of 65x65x1.6 mm3 and an optimized partial GND plane of 30x11.125 mm2. The reconfiguration rate is between 2.41 and 3.99 GHz that can cover the WiMAX and LTE wireless devices by applying just one RF (PIN) switch to change the operating frequency. The antenna operates on the two states of the PIN diode under its two states ON and OFF with (2.7 GHz, and 2.8 GHz) resonant frequencies respectively. The proposed antenna produces acceptable simulation results for the MIMO system by achieving gain from (3-7.2) dBi, less than -14.5 dB coupling effect, less than 0.28 envelope correlation coefficient, and diversity gain range from 8.4-10.

scholarly journals The long-term spatiotemporal variability of sea surface temperature in the northwest Pacific and China offshore

Ocean Science ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 83-97
Author(s):  
Zhiyuan Wu ◽  
Changbo Jiang ◽  
Mack Conde ◽  
Jie Chen ◽  
Bin Deng
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Sea Surface ◽  
Spatiotemporal Variability ◽  
Climate Indices ◽  
Northwest Pacific ◽  
Atmospheric Parameters ◽  
China Sea ◽  
The Past ◽  
Increasing Trend

Abstract. The variability of the sea surface temperature (SST) in the northwest Pacific has been studied on seasonal, annual and interannual scales based on the monthly datasets of extended reconstructed sea surface temperature (ERSST) 3b (1854–2017, 164 years) and optimum interpolation sea surface temperature version 2 (OISST V2 (1988–2017, 30 years). The overall trends, spatial–temporal distribution characteristics, regional differences in seasonal trends and seasonal differences of SST in the northwest Pacific have been calculated over the past 164 years based on these datasets. In the past 164 years, the SST in the northwest Pacific has been increasing linearly year by year, with a trend of 0.033 ∘C/10 years. The SST during the period from 1870 to 1910 is slowly decreasing and staying in the range between 25.2 and 26.0 ∘C. During the period of 1910–1930, the SST as a whole maintained a low value, which is at the minimum of 164 years. After 1930, SST continued to increase until now. The increasing trend in the past 30 years has reached 0.132 ∘C/10 years, and the increasing trend in the past 10 years is 0.306 ∘C/10 years, which is around 10 times that of the past 164 years. The SST in most regions of the northwest Pacific showed a linear increasing trend year by year, and the increasing trend in the offshore region was stronger than that in the ocean and deep-sea region. The change in trend of the SST in the northwest Pacific shows a large seasonal difference, and the increasing trend in autumn and winter is larger than that in spring and summer. There are some correlations between the SST and some climate indices and atmospheric parameters; the correlations between the SST and some atmospheric parameters have been discussed, such as those of the North Atlantic Oscillation (NAO), Pacific Decadal Oscillation (PDO), Southern Oscillation Index (SOI) anomaly, total column water (TCW), NINO3.4 index, sea level pressure (SLP), precipitation, temperature at 2 m (T2) and wind speed. The lowest SST in China offshore basically occurred in February and the highest in August. The SST fluctuation in the Bohai Sea and Yellow Sea (BYS) is the largest, with a range from 5 to 22 ∘C; the SST in the East China Sea (ECS) is from 18 to 27 ∘C; the smallest fluctuations occur in the South China Sea (SCS), maintained at range of 26 to 29 ∘C. There are large differences between the mean and standard deviation in different sea regions.

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