Wszystkie pola: Chang, Y.-C. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Optimization of Multi-Chamber Mufflers with Reverse-Flow Ducts by Algorithm of Simulated Annealing
Autorzy:: Chang, Y-C.
Chiu, M-C.
Powiązania:: https://bibliotekanauki.pl/articles/177998.pdf
Data publikacji:: 2010
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: multi-chamber muffler
reverse-flow
decoupled numerical method
space constraints
simulated algorithm
Opis:: Shape optimization on mufflers within a limited space volume is essential for industry, where the equipment layout is occasionally tight and the available space for a muffler is limited for maintenance and operation purposes. To proficiently enhance the acoustical performance within a constrained space, the selection of an appropriate acoustical mechanism and optimizer becomes crucial. A multi-chamber side muffler hybridized with reverse-flow ducts which can visibly increase the acoustical performance is rarely addressed; therefore, the main purpose of this paper is to numerically analyze and maximize the acoustical performance of this muffler within a limited space. In this paper, the four-pole system matrix for evaluating the acoustic performance – sound transmission loss (STL) – is derived by using a decoupled numerical method. Moreover, a simulated annealing (SA) algorithm, a robust scheme in searching for the global optimum by imitating the softening process of metal, has been used during the optimization process. Before dealing with a broadband noise, the STL’s maximization with respect to a one-tone noise is introduced for the reliability check on the SA method. Moreover, the accuracy check of the mathematical models with respect to various acoustical elements is performed. The optimal result in eliminating broadband noise reveals that the multi-chamber muffler with reverse-flow perforated ducts is excellent for noise reduction. Consequently, the approach used for the optimal design of the noise elimination proposed in this study is easy and effective.
Źródło:: Archives of Acoustics; 2010, 35, 1; 13-33
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: An Assessment of High-Order-Mode Analysis and Shape Optimization of Expansion Chamber Mufflers
Autorzy:: Chiu, M. C.
Chang, Y. C.
Powiązania:: https://bibliotekanauki.pl/articles/178079.pdf
Data publikacji:: 2014
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: higher order wave
eigenfunction
optimization
genetic algorithm
Opis:: A substantial quantity of research on muffler design has been restricted to a low frequency range using the plane wave theory. Based on this theory, which is a one-dimensional wave, no higher order wave has been considered. This has resulted in underestimating acoustical performances at higher frequencies when doing muffler analysis via the plane wave model. To overcome the above drawbacks, researchers have assessed a three-dimensional wave propagating for a simple expansion chamber muffler. Therefore, the acoustic effect of a higher order wave (a high frequency wave) is considered here. Unfortunately, there has been scant research on expansion chamber mufflers equipped with baffle plates that enhance noise elimination using a higher-order-mode analysis. Also, space-constrained conditions of industrial muffler designs have never been properly addressed. So, in order to improve the acoustical performance of an expansion chamber muffler within a constrained space, the optimization of an expansion chamber muffler hybridized with multiple baffle plates will be assessed. In this paper, the acoustical model of the expansion chamber muffler will be established by assuming that it is a rigid rectangular tube driven by a piston along the tube wall. Using an eigenfunction (higher- order-mode analysis), a four-pole system matrix for evaluating acoustic performance (STL) is derived. To improve the acoustic performance of the expansion chamber muffler, three kinds of expansion chamber mufflers (KA-KC) with different acoustic mechanisms are introduced and optimized for a targeted tone using a genetic algorithm (GA). Before the optimization process is performed, the higher-order-mode mathematical models of three expansion chamber mufflers (A-C) with various allocations of inlets/outlets and various chambers are also confirmed for accuracy. Results reveal that the STL of the expansion chamber mufflers at the targeted tone has been largely improved and the acoustic performance of a reverse expansion chamber muffler is more efficient than that of a straight expansion chamber muffler. Moreover, the STL of the expansion chamber mufflers will increase as the number of the chambers that separate with baffles increases.
Źródło:: Archives of Acoustics; 2014, 39, 4; 489-499
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Acoustical Assessment of Automotive Mufflers Using FEM, Neural Networks, and a Genetic Algorithm
Autorzy:: Chang, Y.-C.
Chiu, M.-C.
Wu, M.-R.
Powiązania:: https://bibliotekanauki.pl/articles/177901.pdf
Data publikacji:: 2018
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: acoustics
finite element method
genetic algorithm
muffler optimization
polynomial neural network model
Opis:: In order to enhance the acoustical performance of a traditional straight-path automobile muffler, a multi-chamber muffler having reverse paths is presented. Here, the muffler is composed of two internally parallel/extended tubes and one internally extended outlet. In addition, to prevent noise transmission from the muffler’s casing, the muffler’s shell is also lined with sound absorbing material. Because the geometry of an automotive muffler is complicated, using an analytic method to predict a muffler’s acoustical performance is difficult; therefore, COMSOL, a finite element analysis software, is adopted to estimate the automotive muffler’s sound transmission loss. However, optimizing the shape of a complicated muffler using an optimizer linked to the Finite Element Method (FEM) is time-consuming. Therefore, in order to facilitate the muffler’s optimization, a simplified mathematical model used as an objective function (or fitness function) during the optimization process is presented. Here, the objective function can be established by using Artificial Neural Networks (ANNs) in conjunction with the muffler’s design parameters and related TLs (simulated by FEM). With this, the muffler’s optimization can proceed by linking the objective function to an optimizer, a Genetic Algorithm (GA). Consequently, the discharged muffler which is optimally shaped will improve the automotive exhaust noise.
Źródło:: Archives of Acoustics; 2018, 43, 3; 517-529
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Noise Elimination of Reciprocating Compressors Using FEM, Neural Networks Method, and the GA Method
Autorzy:: Chang, Y.-C.
Chiu, M.-C.
Xie, J.-L.
Powiązania:: https://bibliotekanauki.pl/articles/178126.pdf
Data publikacji:: 2017
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: finite element method
polynomial neural network model
genetic algorithm
group method of data handling
reciprocating compressor
optimization
Opis:: Industry often utilizes acoustical hoods to block noise emitted from reciprocating compressors. However, the hoods are large and bulky. Therefore, to diminish the size of the compressor, a compact discharge muffler linked to the compressor outlet is considered. Because the geometry of a reciprocating compressor is irregular, COMSOL, a finite element analysis software, is adopted. In order to explore the acoustical performance, a mathematical model is established using a finite element method via the COMSOL commercialized package. Additionally, to facilitate the shape optimization of the muffler, a polynomial neural network model is adopted to serve as an objective function; also, a Genetic Algorithm (GA) is linked to the OBJ function. During the optimization, various noise abatement strategies such as a reverse expansion chamber at the outlet of the discharge muffler and an inner extended tube inside the discharge muffler, will be assessed by using the artificial neural network in conjunction with the GA optimizer. Consequently, the discharge muffler that is optimally shaped will decrease the noise of the reciprocating compressor.
Źródło:: Archives of Acoustics; 2017, 42, 2; 189-197
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Numerical Assessment of a One-Mass Spring-Based Electromagnetic Energy Harvester on a Vibrating Object
Autorzy:: Chiu, M.-C.
Chang, Y.-C.
Yeh, L.-J.
Chung, C.-H.
Powiązania:: https://bibliotekanauki.pl/articles/177720.pdf
Data publikacji:: 2016
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: spring
harvester
generator
permanent magnet
simulated annealing
optimization
buckling
Fatigue
Opis:: The paper is an exploration of the optimal design parameters of a space-constrained electromagnetic vibration-based generator. An electromagnetic energy harvester is composed of a coiled polyoxymethylen circular shell, a cylindrical NdFeB magnet, and a pair of helical springs. The magnet is vertically confined between the helical springs that serve as a vibrator. The electrical power connected to the coil is actuated when the energy harvester is vibrated by an external force causing the vibrator to periodically move through the coil. The primary factors of the electrical power generated from the energy harvester include a magnet, a spring, a coil, an excited frequency, an excited amplitude, and a design space. In order to obtain maximal electrical power during the excitation period, it is necessary to set the system’s natural frequency equal to the external forcing frequency. There are ten design factors of the energy harvester including the magnet diameter (D_m), the magnet height (H_m), the system damping ratio (ζ_sys), the spring diameter (D_s), the diameter of the spring wire (d_s), the spring length (ℓ_s), the pitch of the spring (p_s), the spring’s number of revolutions (N_s), the coil diameter (D_c), the diameter of the coil wire (d_c), and the coil’s number of revolutions (N_c). Because of the mutual effects of the above factors, searching for the appropriate design parameters within a constrained space is complicated. Concerning their geometric allocation, the above ten design parameters are reduced to four (D_m, H_m, ζ_sys, and N_c). In order to search for optimal electrical power, the objective function of the electrical power is maximized by adjusting the four design parameters (D_m, H_m, ζ_sys, and N_c) via the simulated annealing method. Consequently, the optimal design parameters of D_m, H_m, ζ_sys, and N_c that produce maximum electrical power for an electromagnetic energy harvester are found.
Źródło:: Archives of Acoustics; 2016, 41, 1; 119-131
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Shape Optimisation of Multi-Chamber Acoustical Plenums Using BEM, Neural Networks, and GA Method
Autorzy:: Chang, Y.-C.
Cheng, H.-C.
Chiu, M.-C.
Chien, Y.-H.
Powiązania:: https://bibliotekanauki.pl/articles/177780.pdf
Data publikacji:: 2016
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: boundary element method
plenum
centre-opening baffle
polynomial neural network model
group method of data handling
optimisation
genetic algorithm
Opis:: Research on plenums partitioned with multiple baffles in the industrial field has been exhaustive. Most researchers have explored noise reduction effects based on the transfer matrix method and the boundary element method. However, maximum noise reduction of a plenum within a constrained space, which frequently occurs in engineering problems, has been neglected. Therefore, the optimum design of multi-chamber plenums becomes essential. In this paper, two kinds of multi-chamber plenums (Case I: a two-chamber plenum that is partitioned with a centre-opening baffle; Case II: a three-chamber plenum that is partitioned with two centre-opening baffles) within a fixed space are assessed. In order to speed up the assessment of optimal plenums hybridized with multiple partitioned baffles, a simplified objective function (OBJ) is established by linking the boundary element model (BEM, developed using SYSNOISE) with a polynomial neural network fit with a series of real data – input design data (baffle dimensions) and output data approximated by BEM data in advance. To assess optimal plenums, a genetic algorithm (GA) is applied. The results reveal that the maximum value of the transmission loss (TL) can be improved at the desired frequencies. Consequently, the algorithm proposed in this study can provide an efficient way to develop optimal multi-chamber plenums for industry.
Źródło:: Archives of Acoustics; 2016, 41, 1; 43-53
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Shape Optimization of Mufflers Composed of Multiple Rectangular Fin-Shaped Chambers Using Differential Evolution Method
Autorzy:: Chiu, M.-C.
Chang, Y.-C.
Cheng, H.-C.
Tai, W.-T.
Powiązania:: https://bibliotekanauki.pl/articles/177237.pdf
Data publikacji:: 2015
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: fin
multi-chamber
high-order-mode
differential evolution
Opis:: There has been considerable research done on multi-chamber mufflers used in the elimination of industrial venting noise. However, most research has been restricted to lower frequencies using the plane wave theory. This has led to underestimating acoustical performances at higher frequencies. Additionally, because of the space-constrained problem in most plants, the need for optimization of a compact muffler seems obvious. Therefore, a muffler composed of multiple rectangular fin-shaped chambers is proposed. Based on the eigenfunction theory, a four-pole matrix used to evaluate the acoustic performance of mufflers will be deduced. A numerical case for eliminating pure tones using a three-fin-chamber muffler will also be examined. To delineate the best acoustical performance of a space-constrained muffler, a numerical assessment using the Differential Evolution (DE) method is adopted. Before the DE operation for pure tone elimination can be carried out, the accuracy of the mathematical model must be checked using experimental data. The results reveal that the broadband noise has been efficiently reduced using the three-fin-chamber muffler. Consequently, a successful approach in eliminating a pure tone using optimally shaped three-fin-chamber mufflers and a differential evolution method within a constrained space has been demonstrated.
Źródło:: Archives of Acoustics; 2015, 40, 3; 311-319
0137-5075
Pojawia się w:: Archives of Acoustics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Saving water used for vegetable production by applying regulated deficit irrigation practices
Autorzy:: Chang, Y.-S.
Lin, K.-H.
Chen, Y.-J.
Wu, C.-W.
Chang, Y.-J.
Powiązania:: https://bibliotekanauki.pl/articles/13003875.pdf
Data publikacji:: 2021
Wydawca:: Uniwersytet Przyrodniczy w Lublinie. Wydawnictwo Uniwersytetu Przyrodniczego w Lublinie
Źródło:: Acta Scientiarum Polonorum. Hortorum Cultus; 2021, 20, 3; 27-36
1644-0692
Pojawia się w:: Acta Scientiarum Polonorum. Hortorum Cultus
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Surface Modification of Self-Consolidated Microporous Ti Implant Compacts Fabricated by Electro-Discharge-Sintering in Air
Autorzy:: Jo, Y. J.
Yoon, Y. H.
Kim, Y. H.
Chang, S. Y.
Kim, J. Y.
Lee, Y. K.
Van Tyne, C. J.
Lee, W. H.
Powiązania:: https://bibliotekanauki.pl/articles/356790.pdf
Data publikacji:: 2017
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: titanium
implant
porous
sintering
X-ray photoelectron spectroscopy (XPS)
Opis:: A single pulse of 0.75-2.0 kJ/0.7g of atomized spherical Ti powders from 300 mF capacitor was applied to produce a microporous Ti implant compact by electro-discharge-sintering (EDS). A solid core in the middle of the compact surrounded by a microporous layer was found. X-ray photoelectron spectroscopy was employed to study the surface characteristics of the EDS Ti compact and it revealed that Ti, C and O were the main constituents on the surface with a smaller amount of N. The surface was lightly oxidized and was primarily in the form of TiO₂ resulting from the air oxidation during EDS processing. The lightly oxidized surface of the EDS compact also exhibited Ti nitrides such as TiN and TiON, which revealed that the reaction between air constituents and the Ti powders even in times as short as 128 msec.
Źródło:: Archives of Metallurgy and Materials; 2017, 62, 2B; 1287-1291
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Impact of mesh quality on the numerical estimation of saturated water conductivity of pore media
Autorzy:: Gackiewicz, B.
Lamorski, K.
Slawiński, C.
Hsu, S.-Y.
Chang, L.-C.
Powiązania:: https://bibliotekanauki.pl/articles/2082923.pdf
Data publikacji:: 2020
Wydawca:: Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:: porous media
numerical modelling
hydraulic
conductivity
mesh accuracy
Opis:: The numerical modelling of transport phenomena in porous media often requires a compromise between grid precision and the accuracy of simulation results. This study demonstrates the impact of errors on the accuracy of the reproduction of the actual pore space by the numerical grid on the estimated values of the saturated water conductivity. Four types of computational grids with varying levels of complexity were prepared for each of the 12 tomographic images of the porous specimens. The specific surfaces and total porosities were calculated for each of the meshes and compared with those parameters calculated for binarized tomographic images. Simulations of steady flow were performed on the computational grids, and the saturated water conductivity values were calculated. It has been shown that an insufficiently accurate mesh only reproduces the largest pore spaces in the analysed sample, which most often leads to an underestimation of the water conductivity coefficient. The following criterion for the optimal accuracy of the computational grid is proposed, it is based on the voxel size of the tomographic images of the porous media: the minimum size of the cell in the mesh used for simulations has to be at most two times the size of the voxel used in the tomographic scans of the porous medium.
Źródło:: International Agrophysics; 2020, 34, 4; 473-483
0236-8722
Pojawia się w:: International Agrophysics
Dostawca treści:: Biblioteka Nauki

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