Vibration Analysis of a Horizontal Partially Fluid-Filled Cylindrical Shell Considering Sloshing Effect of Free Surface

2019 ◽  
Author(s):  
Luyan Pan ◽  
Xiang Zhu ◽  
Tianyun Li ◽  
Yueyang Han ◽  
Xiaotian Liang
Keyword(s):  
Cylindrical Shell ◽  
Free Surface ◽  
Pressure Fluctuation ◽  
High Frequency ◽  
Natural Frequencies ◽  
Low Frequency ◽  
Modal Frequency ◽  
High Frequency Part ◽  
Sloshing Frequency ◽  
The Impact

Abstract The free and forced vibrations of a horizontal partially fluid-filled cylindrical shell with sloshing effect are studied based on the finite element method. The structure and inner fluid taking into account the sloshing effect of the free surface are simulated by the shell and acoustic elements respectively. The natural frequencies of sloshing fluid and shell structure are calculated simultaneously by the FEM. To verify the accuracy of the results, the shell’s natural frequencies are compared with published results. The effects of the structural parameters and fluid depth on the vibration of the coupled system are discussed. The natural frequencies of a sloshing fluid can be divided into low-frequency and high-frequency part, and the low-frequency part refers to the pressure fluctuation caused by the sloshing of the free surface, while the high-frequency part corresponds to the pressure fluctuation of the particles below the free surface. The thinner the shell thickness is, the lower the sloshing frequency of free surface and coupled modal frequency of the shell are. With the increase of the liquid depth, the natural sloshing frequency of the free surface increases slightly while the coupled modal frequency of the shell decreases. The impact of the free surface effect on the coupled vibration cannot be omitted when the shell’s natural frequencies are close to the sloshing frequencies.

scholarly journals Statistical regularities cause attentional suppression with target-matching distractors

2020 ◽  
Author(s):  
Dirk Kerzel ◽  
Stanislas Huynh Cong
Keyword(s):  
High Frequency ◽  
Target Location ◽  
Low Frequency ◽  
Target Display ◽  
Distractor Location ◽  
Target Feature ◽  
Statistical Regularities ◽  
Feature Based ◽  
The Impact ◽  
Target Matching

AbstractVisual search may be disrupted by the presentation of salient, but irrelevant stimuli. To reduce the impact of salient distractors, attention may suppress their processing below baseline level. While there are many studies on the attentional suppression of distractors with features distinct from the target (e.g., a color distractor with a shape target), there is little and inconsistent evidence for attentional suppression with distractors sharing the target feature. In this study, distractor and target were temporally separated in a cue–target paradigm, where the cue was shown briefly before the target display. With target-matching cues, RTs were shorter when the cue appeared at the target location (valid cues) compared with when it appeared at a nontarget location (invalid cues). To induce attentional suppression, we presented the cue more frequently at one out of four possible target positions. We found that invalid cues appearing at the high-frequency cue position produced less interference than invalid cues appearing at a low-frequency cue position. Crucially, target processing was also impaired at the high-frequency cue position, providing strong evidence for attentional suppression of the cued location. Overall, attentional suppression of the frequent distractor location could be established through feature-based attention, suggesting that feature-based attention may guide attentional suppression just as it guides attentional enhancement.

scholarly journals The Impact of Physical Environment and Regional Image on Tourist’s Experiential Values and Feelings: An Example of Nanzhuang Area in Taiwan

2015 ◽  
Vol 10 (11) ◽  
pp. 94
Author(s):  
Shwu-Ing Wu ◽  
Li Chia Huang
Keyword(s):  
Significant Influence ◽  
Physical Environment ◽  
High Frequency ◽  
Low Frequency ◽  
Equation Modeling ◽  
Independent Variables ◽  
Frequency Group ◽  
Experiential Value ◽  
The Impact ◽  
Two Independent Variables

With the booming global tourism activities, many countries around the world are actively promoting regional tourism. Thus, understanding the tourists’ needs is important in developing tourism promotion strategies. With Nanzhuang Township, Miaoli County as the case study, this paper discusses the influence of the two independent variables, the tangible physical environment and the intangible regional image, tourists’ experiential value and the feelings after tourism. This study conducted a questionnaire survey on tourists who have visited Nanzhuang Township, Miaoli County, by convenience sampling, in order to construct the model of regional experience marketing effect. A total of 743 effective samples were retrieved. After analysis by structural equation modeling (SEM), it is found that: (1) the physical environment has a positive and significant influence on the tourists’ experiential value; (2) regional image has a positive and significant influence on the tourist’s experiential value; (3) the experiential value has a positive and significant influence on satisfaction; (4) satisfaction has a positive and significant influence on trust and commitment; (5) trust has no significant influence on commitment. Regarding the two independent variables, regional image has more influence. In addition, after comparing the group models by clustering with the high and low frequency of the number of visits, it is found that there are some differences between the high frequency group and the low frequency group, where the regional image of the high frequency group has a greater influence on the experiential value and the physical environment of the low frequency group has a greater influence on the experiential value. The findings can serve as reference for the local government and the tourism operators to develop regional marketing strategies.

Non-uniform dependence on initial data for the generalized Degasperis–Procesi equation on the line

2016 ◽  
Vol 27 (03) ◽  
pp. 1650026
Author(s):  
Yanggeng Fu ◽  
Zanping Yu ◽  
Jianhe Shen
Keyword(s):  
Initial Data ◽  
Sobolev Spaces ◽  
High Frequency ◽  
Low Frequency ◽  
Approximate Solutions ◽  
Solution Map ◽  
High Frequency Part ◽  
Uniformly Continuous

In this paper, we show that the solution map of the generalized Degasperis–Procesi (gDP) equation is not uniformly continuous in Sobolev spaces [Formula: see text] for [Formula: see text]. Our proof is based on the estimates for the actual solutions and the approximate solutions, which consist of a low frequency and a high frequency part. It also exploits the fact that the gDP equation conserves a quantity which is equivalent to the [Formula: see text] norm.

Dynamic relation between global Islamic and conventional sectoral stock and bonds indexes

2020 ◽  
Vol 07 (02) ◽  
pp. 2050006
Author(s):  
Sukriye Tuysuz
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Stock Index ◽  
High Frequency Part ◽  
Dynamic Relation ◽  
The Relationship

This paper examines the relationship between 10 Global sectoral conventional and Islamic assets. For each sector, a conventional, an Islamic stock index and a bond are retained. The analyzed relations are done by taking into account diverse investment horizons by using MODWT and GARCH-DCC-type models. Our results indicate that adding bond indexes into a portfolio composed with conventional stock or Islamic stock is efficient. As for the correlations between conventional and Islamic sectoral indexes, they depend on the sector. Relations between returns of securities are quite similar to the relations between high-frequency part of these series and are very volatile at low frequency.

Feature Analysis of Mechanical Fault Signals Based on the Wavelet Transform Technique

2010 ◽  
Vol 139-141 ◽  
pp. 2502-2505
Author(s):  
Bing Cheng Wang ◽  
Zhao Hui Ren
Keyword(s):  
High Frequency ◽  
Amplitude Spectrum ◽  
Low Frequency ◽  
Feature Analysis ◽  
Oil Whip ◽  
Frequency Components ◽  
Quantitative Manner ◽  
Beat Phenomenon ◽  
The Impact ◽  
The Relationship

Simulated four different fault signals in the lab, the authors then used wavelet scalogram and amplitude spectrum to make analysis on the above four fault signals and abstract each spectrum characteristics. Wavelet scalogram was able to extract the characteristic’s frequency, show the impact components caused by rub-impact, show the beat phenomenon caused by oil whip and show the irreducible high frequency components as well as the complex low-frequency components. Amplitude spectrum was able to show the energy size distribution at various frequency bands and able to analyze and calculate the relationship between various frequency components. Thus they express the relationship between various frequency banks from a quantitative manner. Therefore, combining the wavelet scalogram and amplitude spectrum when making analysis, as they complement and verify each other, it will enhance the reliability when extract and analyze the characteristics of fault signal.

scholarly journals Extracting super-resolution details directly from a diffraction-blurred image or part of its frequency spectrum

2019 ◽  
Author(s):  
Edward Y Sheffield
Keyword(s):  
High Frequency ◽  
Simulation Experiment ◽  
Fourier Spectrum ◽  
Low Frequency ◽  
Super Resolution ◽  
Diffraction Limit ◽  
Full Information ◽  
High Frequency Part ◽  
Blurred Image ◽  
Blurred Images

It is usually believed that the low frequency part of a signal’s Fourier spectrum represents its profile, while the high frequency part represents its details. Conventional light microscopes filter out the high frequency parts of image signals, so that people cannot see the details of the samples (objects being imaged) in the blurred images. However, we find that in a certain “resolvable condition”, a signal’s low frequency and high frequency parts not only represent profile and details respectively. Actually, any one of them also contains the full information (including both profile and details) of the sample’s structure. Therefore, for samples with spatial frequency beyond diffraction-limit, even if the image’s high frequency part is filtered out by the microscope, it is still possible to extract the full information from the low frequency part. On the basis of the above findings, we propose the technique of Deconvolution Super-resolution (DeSu-re), including two methods. One method extracts the full information of the sample’s structure directly from the diffraction-blurred image, while the other extracts it directly from part of the observed image’s spectrum (e.g., low frequency part). Both theoretical analysis and simulation experiment support the above findings, and also verify the effectiveness of the proposed methods.

scholarly journals Tracking the impact of COVID-19 on economic inequality at high frequency

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0249121
Author(s):  
Oriol Aspachs ◽  
Ruben Durante ◽  
Alberto Graziano ◽  
Josep Mestres ◽  
Marta Reynal-Querol ◽  
...  
Keyword(s):  
High Frequency ◽  
Public Policies ◽  
Economic Inequality ◽  
Low Frequency ◽  
Government Support ◽  
Foreign Born ◽  
Wage Earners ◽  
The Impact ◽  
Wage Cuts ◽  
Fine Tune

Pandemics have historically had a significant impact on economic inequality. However, official inequality statistics are only available at low frequency and with considerable delay, which challenges policymakers in their objective to mitigate inequality and fine-tune public policies. We show that using data from bank records it is possible to measure economic inequality at high frequency. The approach proposed in this paper allows measuring, timely and accurately, the impact on inequality of fast-unfolding crises, like the COVID-19 pandemic. Applying this approach to data from a representative sample of over three million residents of Spain we find that, absent government intervention, inequality would have increased by almost 30% in just one month. The granularity of the data allows analyzing with great detail the sources of the increases in inequality. In the Spanish case we find that it is primarily driven by job losses and wage cuts experienced by low-wage earners. Government support, in particular extended unemployment insurance and benefits for furloughed workers, were generally effective at mitigating the increase in inequality, though less so among young people and foreign-born workers. Therefore, our approach provides knowledge on the evolution of inequality at high frequency, the effectiveness of public policies in mitigating the increase of inequality and the subgroups of the population most affected by the changes in inequality. This information is fundamental to fine-tune public policies on the wake of a fast-moving pandemic like the COVID-19.

Layout Effects on High Frequency and Noise Parameters in MOSFETs

2017 ◽  
Vol 6 (1) ◽  
pp. 88
Author(s):  
Asmaa Nur Aqilah Zainal Badri ◽  
Norlaili Mohd Noh ◽  
Shukri Bin Korakkottil Kunhi Mohd ◽  
Asrulnizam Abd Manaf ◽  
Arjuna Marzuki ◽  
...  
Keyword(s):  
High Frequency ◽  
Noise Figure ◽  
Low Frequency ◽  
Frequency Noise ◽  
Noise Parameters ◽  
Trench Isolation ◽  
Gate Resistance ◽  
The Impact ◽  
Rf Noise ◽  
Better Than

<p>This study reviews related studies on the impact of the layout dependent effects on high frequency and RF noise parameter performances, carried out over the past decade. It specifically focuses on the doughnut and multi- finger layouts. The doughnut style involves the polygonal and the 4- sided techniques, while the multi-finger involving the narrow-oxide diffusion (OD) and multi-OD. The polygonal versus 4-sided doughnut, and the narrow-OD with multi-fingers versus multi-OD with multi- fingers are reviewed in this study. The high frequency parameters, which are of concern in this study, are the cut- off frequency (f<sub>T</sub>) and the maximum frequency (f<sub>MAX</sub>), whereas the noise parameters involved are noise resistance (R<sub>N</sub>) and the minimum noise figure (NF<sub>min</sub>). In addition, MOSFET parameters, which are affected by the layout style that in turn may contribute to the changes in these high frequency, and noise parameters are also detailed. Such parameters include transconductance (G<sub>m</sub>); gate resistance (R<sub>g</sub>); effective mobility (μ<sub>eff</sub>); and parasitic capacitances (c<sub>gg</sub> and c<sub>gd</sub>). Investigation by others has revealed that the polygonal doughnut may have a larger total area in comparison with the 4- sided doughnut. It is also found by means of this review that the multi-finger layout style with narrow-OD and high number of fingers may have the best performance in f<sub>T</sub> and f<sub>MAX</sub>, owing partly to the improvement in G<sub>m</sub>, μ<sub>eff</sub>, c<sub>gg</sub>, c<sub>gd</sub> and low frequency noise (LFN). A multi-OD with a lower number of fingers may lead to a lower performance in f<sub>T</sub> due to a lower G<sub>m</sub>. Upon comparing the doughnut and the multi-finger layout styles, the doughnuts appeared to perform better than a standard multi-finger layout for f<sub>T</sub>, f<sub>MAX</sub>, G<sub>m</sub> and μ<sub>eff</sub> but are poorer in terms of LFN. It can then be concluded that the narrow-OD multi-finger may cause the increase of c<sub>gg</sub> as the transistor becomes narrower, whereas a multi-OD multi-finger may have high R<sub>g</sub> and therefore may lead to the increase of f<sub>T</sub> and f<sub>MAX</sub> as the transistor becomes narrower. Besides, the doughnut layout style has a higher G<sub>m</sub> and f<sub>T</sub>, leading to larger μ<sub>eff</sub> from the elimination of shallow trench isolation (STI) stress.</p>

Noise Test and Analysis of Automobile Engine

2013 ◽  
Vol 307 ◽  
pp. 196-199 ◽  
Author(s):  
Yan Liu ◽  
Yan Bin Jia ◽  
Xiao Juan Zhang ◽  
Zong Cai Liu ◽  
Yong Chao Ren ◽  
...  
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Sound Insulation ◽  
Engine Noise ◽  
High Frequency Part ◽  
Speed Measure ◽  
Dash Panel ◽  
Noise Frequency ◽  
Noise Test ◽  
Analysis Engine

To test different car’s noise in a semi-anechoic room with different engine’s speed, measure and analysis engine noise’s characteristics and the dash panel’s sound insulation quantity. The conclusion is that：the engine noise gets bigger 10 dB(A) when engine speeds up every 1000 r/min; engine noise’s frequency mainly distributed in 1600 ~ 4000 Hz; peak part concentrates in the range 100 ~ 400 Hz; engine noise has no direct relation to engine’s displacement; cab noise frequency mainly concentrated in the range 250 ~ 630 Hz and the peaks exist in the intermediate and low frequency part, the high frequency part attenuates obviously which show the car’s dash panel has a good noise insulation and absorption effect in the high frequency part but not too ideal at the intermediate and low frequency especially in the range 250 ~ 630 Hz. These results have high practical value for the design of the automotive to decline noise and vibration.

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