Feature Variation and Its Impact on Structural Acoustic Response Predictions

2000 ◽  
Author(s):  
Kenneth A. Cunefare
Keyword(s):  
Acoustic Power ◽  
Reference State ◽  
Analysis Method ◽  
Acoustic Response ◽  
Single Degree Of Freedom ◽  
Model Fidelity ◽  
Resonance Frequencies ◽  
Quadratic Response ◽  
Sdof Analysis ◽  
The Impact

Abstract This paper presents a screening technique to assess the impact on model fidelity introduced by variations in the properties or positions of features in harmonically forced fluid-loaded structural acoustic models. While fluid-loading is included, it is not a requirement or restriction to the methods presented. The perspective taken is one of knowledge of a reference state, with a desire to determine the impact on the total radiated acoustic power due to perturbations in the reference state. Such perturbations change the predicted resonance frequencies of a structure under consideration, and hence, change the predicted response amplitudes. The method uses a single degree of freedom response model in the local region of each fluid-loaded resonance, coupled with eigenvalue sensitivities or variations, to estimate the perturbation impact. The SDOF model argues for the use of proportional bandwidth analyses. Elements of the analysis method are not necessarily restricted to model perturbations nor acoustic power, rather they may be used to assess the perturbation of any quadratic response quantity of interest due to changes in resonance frequency. The SDOF analysis method is limited by its assumption of constant modal forcing between the reference and perturbed states.

Feature Variation and its Impact on Structural Acoustic Response Predictions

2003 ◽  
Vol 125 (1) ◽  
pp. 31-38
Author(s):  
Kenneth A. Cunefare
Keyword(s):  
Acoustic Power ◽  
Reference State ◽  
Acoustic Response ◽  
Model Fidelity ◽  
Quantity Of Interest ◽  
Resonance Frequencies ◽  
Quadratic Response ◽  
Constant Bandwidth ◽  
Bandwidth Analysis ◽  
The Impact

This paper presents a screening technique to assess the impact on model fidelity introduced by variations in the properties or positions of features in harmonically forced fluid-loaded structural acoustic models. The perspective taken is one of knowledge of a reference state, with a desire to determine the impact on the total radiated acoustic power due to perturbations in the reference state. Such perturbations change the predicted resonance frequencies of a structure under consideration, and hence, change the predicted response amplitudes. The method uses a single degree of freedom response model in the local region of each fluid-loaded resonance, coupled with eigenvalue sensitivities or variations, to estimate the perturbation impact. The perturbation is scaled by the degree to which each given mode participates in the response quantity of interest. The SDOF model yields results that indicate that proportional bandwidth analysis will be less sensitive to perturbation than constant bandwidth analysis. This is demonstrated through comparison of a constant bandwidth analysis and a 1/3 octave analysis applied to the same system. Elements of the analysis method are not necessarily restricted to model perturbations nor acoustic power, rather they may be used to assess the perturbation of any quadratic response quantity of interest due to changes in resonance frequency.

ANALISIS PENGARUH PEMBANGUNAN JALAN LAYANG JANTI TERHADAP PERKEMBANGAN TATA RUANG KAWASAN JANTI STUDI KASUS : KAWASAN JANTI, DESA CATURTUNGGAL, KABUPATEN SLEMAN, D. I. YOGYAKARTA

2017 ◽  
Vol 11 (3) ◽  
pp. 255
Author(s):  
Jeky El Boru
Keyword(s):  
Road Network ◽  
Open Space ◽  
Qualitative Description ◽  
Analysis Method ◽  
Open Spaces ◽  
The Road ◽  
Before And After ◽  
Linkage Method ◽  
The Impact ◽  
Parking Place

Abstract: This research aims to analyze the impact of Janti Flyover Construction toward the growth of layout at Janti Urban Area, including structured space, open space, and linkage. Method used for data collecting are observation, air photograph monitoring, and interview, whereas the analysis method is qualitative description, which is the superimposed method of two layers, that are the layout condition before and after flyover construction. The result shows that the impact of Janti Flyover construction can be seen on building mass (solid), the increasing number of open spaces, including the road network, parking place, and park, whereas the relation between spaces, visually and structurally, can be seen on the growth of buildings which have new shapes and styles, therefore the performance of the overall building does not have a proportional shape. Considering Janti Street at the collective relation, its role is getting stronger as the main frame road network.Keywords: Flyover construction, layout changing, Janti AreaAbstrak: Penelitian ini bertujuan untuk menganalisis pengaruh pembangunan Jalan Layang Janti terhadap perkembangan tata ruang Kawasan Janti, meliputi ruang terbangun, ruang terbuka, serta hubungan antar ruang (“linkage”). Metode pengumpulan data dilakukan melalui observasi, pengamatan foto udara, dan wawancara; sedangkan metode analisis melalui deskripsi secara kualitatif yang berupa “superimposed method” dari dua lapisan kondisi lahan, yakni kondisi tata ruang sebelum dan sesudah pembangunan jalan layang. Hasil penelitian menunjukkan bahwa pengaruh pembangunan Jalan Layang Janti terdapat pada massa bangunan (“solid”), pertambahan ruang terbuka yang berupa jaringan jalan, parkir, dan taman; sedangkan pada hubungan antar ruang ̶ secara visual dan struktural ̶ yakni tumbuhnya bangunan dengan bentuk dan gaya baru, sehingga bentuk tampilan bangunan secara keseluruhan tidak proporsional. Pada hubungan kolektif, Jalan Janti semakin kuat perannya sebagai kerangka utama jaringan jalan.Kata kunci : Pembangunan jalan layang, tata ruang, Kawasan Janti

A REVIEW ON THE BENEFITS OF HORTICULTURAL THERAPY FOR RETIREMENT COMMUNITY IN MALAYSIA

2017 ◽  
Vol 2 (1) ◽  
pp. 1
Author(s):  
Amirul Amin Ismail ◽  
Ismail Samsuddin ◽  
Azman Zainonabidin ◽  
Harlina Mohd Ali
Keyword(s):  
Well Being ◽  
The Elderly ◽  
Retirement Community ◽  
Analysis Method ◽  
Horticultural Therapy ◽  
Seamless Integration ◽  
Ageing Society ◽  
After Effects ◽  
Malaysian Population ◽  
The Impact

By the year 2030, Malaysian population will experience the after effects of the rapid growth of ageing society. This paper investigates the impact of seamless integration of horticultural activity in the new residential typology of retirement community. It is believed that horticultural therapy is not only beneficial for physical and psychological but also promotes socialisation opportunities among the elderly. Comparative analysis method on selected precedent studies has been carried out and analysed in accordance with Malaysian context. Initial findings indicate that a retirement community with horticultural activity gives therapy for healthier well-being. This therapeutic activity can be apositive change in elderly lifestyle and essential towards the establishment of retirement community in Malaysia. 

Cooling Efficiencies of a NiTi-Based Cooling Process

2013 ◽  
Author(s):  
Marvin Schmidt ◽  
Andreas Schütze ◽  
Stefan Seelecke
Keyword(s):  
Solid State ◽  
Thermodynamic Analysis ◽  
Cooling System ◽  
Analysis Method ◽  
Efficiency Ratio ◽  
Cooling Process ◽  
First Results ◽  
Work Input ◽  
Underlying Mechanisms ◽  
The Impact

Energy saving and environmental protection are topics of growing interest. In the light of these aspects alternative refrigeration principles become increasingly important. Shape memory alloys (SMA), especially NiTi alloys, generate a large amount of latent heat during solid state phase transformations, which can lead to a significant cooling effect in the material. These materials do not only provide the potential for an energy-efficient cooling process, they also minimize the impact on the environment by reducing the need for conventional ozone-depleting refrigerants. Our paper, presenting first results obtained in a project within the DFG Priority Program SPP 1599 “Ferroic Cooling”, focuses on the thermodynamic analysis of a NiTi-based cooling system. We first introduce a suitable cooling process and subsequently illustrate the underlying mechanisms of the process in comparison with the conventional compression refrigeration system. We further introduce a graphical solution to calculate the energy efficiency ratio of the system. This thermodynamic analysis method shows the necessary work input and the heat absorption of the SMA in stress/strain- or temperature/entropy-diagrams, respectively. The results of the calculations underline the high potential of this solid-state cooling methodology.

Analysis of Uzbekistan's Planting Industry Growth Based on Shift-Share Method

2021 ◽  
Vol 7 (4) ◽  
pp. 7-13
Author(s):  
Zhang Lingzhi
Keyword(s):  
Agricultural Development ◽  
Industry Structure ◽  
Analysis Method ◽  
Industry Growth ◽  
Important Indicator ◽  
Industrial Policies ◽  
The Impact

Changes in the structure of the planting industry are an important indicator of the level of agricultural development. This paper applies the shift-share analysis method to analyse the growth of Uzbekistan’s planting industry from 2011 to 2018 into three parts: the national share, the industry mix and the regional shift component. The study found that the growth of Uzbekistan’s national planting industry has driven the growth of the planting industry in each state. Although the output of grain and cotton is still the main output of the planting industry, the scale of grain and cotton is relatively shrinking, and the output of vegetables, melons, fruits and berries, and grapes is on the rise. Because of the obvious differences in the impact of the planting industry structure and competitiveness on yield growth in Uzbekistan states, each state should formulate corresponding industrial policies according to the advantages and characteristics of planting industry.

Development of Model for Acoustic Noise Generated from Bedload in Rivers 

2021 ◽  
Author(s):  
Mohamad Nasr ◽  
Thomas Geay ◽  
Sébastien Zanker ◽  
Recking Alain
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Impact Velocity ◽  
Acoustic Noise ◽  
Acoustic Power ◽  
Bedload Transport ◽  
Empirical Formulas ◽  
Impact Rate ◽  
Flux Measurements ◽  
The Impact

<p>Quantifying bedload transport is important for many applications such as river management and hydraulic structures protection. Bedload flux measurements can be achieved using physical sampler methods. However, these methods are expensive, time-consuming, and difficult to operate during high discharge events. Besides, these methods do not permit to capture the spatial and temporal variability of bedload transport flux. Recently, alternative measuring technologies have been developed to continuously monitor bedload flux and grain size distribution using passive or active sensors. Among them, the hydrophone was used to monitor bedload transport by recording the sounds generated by bedload particles colliding on the river bed (referred as self-generated noise SGN). The acoustic power of SGN was correlated with bedload flux in field experiments. To better understand these experimental results and to estimate measurement uncertainties, we developed a theoretical model to simulate the SGN. The model computes an estimation of the power spectral density (PSD)by considering the contribution of all signals generated by impacts between bedload particles and the riverbed, and accounting for the attenuation of the acoustic signal between the source and the hydrophone position due to river propagation effects,. In this model, we</p><p>The energy of acoustic noise generated from the collision between two particles is mainly dependent on the transported particles' diameter and the impact velocity. We tested different empirical formulas for the estimation of the number of impact (impact rate) and the impact velocity depending on particle size and hydraulic conditions. To characterize the acoustic power losses as a function of distance and frequency, we used an attenuation function which was experimentally calibrated for different French rivers.</p><p>We tested the model on a field dataset comprising acoustic and bedload flux measurements. The results indicate that the PSD model allows estimating acoustic power (in between a range of one order of magnitude) for most of the rivers considered.  The model sensitivity was evaluated. In particular, we observed that it is very sensitive to the empirical formulas used to determine the impact rate and impact speed. In addition, special attention should be kept in mind on the assumption of the grain size distribution of riverbed which can generate large variability in some rivers particularly in rivers with a significant sand fraction.</p>

Fighting disinformation. The impact of the Covid-19 on youth trust in European Institutions

2021 ◽  
pp. 71-89
Author(s):  
Lucia D’Ambrosi ◽  
Isabel Iniesta ◽  
Mariaeugenia Parito ◽  
Ricardo Pérez-Calle
Keyword(s):  
Multivariate Analysis ◽  
Young People ◽  
Quantitative Study ◽  
Sense Of Belonging ◽  
Analysis Method ◽  
Eu Integration ◽  
European Institutions ◽  
Communicative Actions ◽  
The Impact ◽  
The Eu

The pandemic crisis and the linked infodemic are extraordinary cases to test the EU capability to manage the disinformation disorder, especially towards young people. This paper aims to analyse the impact of the EU communicative actions regarding disinformation about Covid-19, on trust and sense of belonging in young Italian and Spanish university students. The research presents an exploratory and quantitative study that uses a second-generation multivariate analysis method. The results show that trust can be very well the resource on which EU communicative actions may positively impact. Nevertheless, our study reveals that the EU in-stitutions measures have not increased sense of belonging in EU integration.

scholarly journals Performance analysis of the thermoacoustic refrigerator with the standing wave and air as a working fluid

2018 ◽  
Vol 44 ◽  
pp. 00063 ◽  
Author(s):  
Jakub Kajurek ◽  
Artur Rusowicz
Keyword(s):  
Temperature Difference ◽  
High Reliability ◽  
Power Input ◽  
Acoustic Power ◽  
Operating Frequency ◽  
Working Fluid ◽  
Resonator Length ◽  
Environmental Friendliness ◽  
The Impact ◽  
Thermoacoustic Refrigerator

Thermoacoustic refrigerator is a new and emerging technology capable of transporting heat from a low-temperature source to a high-temperature source by utilizing the acoustic power input. These devices, operating without hazardous refrigerants and owning no moving components, show advantages of high reliability and environmental friendliness. However, simple to fabricate, the designing of thermoacoustic refrigerators is very challenging. This paper illustrates the impact of significant factors on the performance of the thermoacoustic refrigerator which was measured in terms of the temperature difference generated across the stack ends. The experimental device driven by a commercial loudspeaker and air at atmospheric pressure as a working fluid was examined under various resonator length and operating frequencies. The results indicate that appropriate resonator’s length and operating frequency lead to an increase in the temperature difference created across the stack. The maximum values were achieved for operating frequency equalled to 200 and 300 Hz whereas resonator length corresponded to the half-length of the acoustic wave for these frequencies. The results of experiment also confirm that relationship between these parameters is strongly affected by the stack spacing, which in this research was equalled to 0.4 mm.

Analysis Method for Impact and Dispersion Behavior of Water-Filled Tank

2018 ◽  
Vol 4 (4) ◽  
Author(s):  
Hidekazu Takazawa ◽  
Kazuma Hirosaka ◽  
Katsumasa Miyazaki ◽  
Norihide Tohyama ◽  
Naomi Matsumoto
Keyword(s):  
Structural Damage ◽  
Impact Test ◽  
Velocity Ratio ◽  
Research Centre ◽  
Dispersion Pattern ◽  
Test Results ◽  
Analysis Method ◽  
Cylindrical Tank ◽  
Dispersion Behavior ◽  
The Impact

A new Japanese nuclear regulation involves estimating the possible damage to plant structures due to intentional aircraft impact. The effect of aircraft impact needs to be considered in the existing nuclear power plants. The structural damage and fuel dispersion behavior after aircraft impact into plant structures can be evaluated using finite element analysis (FEA). FEA needs validated experimental data to determine the reliability of the results. In this study, an analysis method was validated using a simple model such as a cylindrical tank. Numerical simulations were conducted to evaluate the impact and dispersion behavior of a water-filled cylindrical tank. The simulated results were compared with the test results of the VTT Technical Research Centre of Finland (VTT). The simulations were carried out using a multipurpose FEA code LS-DYNA®. The cylindrical tank was modeled using a shell element, and the tank water was modeled using smoothed particle hydrodynamics (SPH) elements. First, two analysis models were used to evaluate the effect of the number of SPH elements. One had about 300,000 SPH elements and the other had 37,000 SPH elements. The cylindrical tank ruptured in the longitudinal direction after crashing into a rigid wall, and the filled water dispersed. There were few differences in the simulated results when using different numbers of SPH elements. The VTT impact test was simulated with an arbitrary Lagrangian-Eulerian (ALE) element to consider the air drag. The analytical dispersion pattern and history of dispersion velocity ratio agreed well with the impact test results.

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