Academic literature on the topic 'Equivalent-layer technique'
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Journal articles on the topic "Equivalent-layer technique"
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Oliveira Jr., Vanderlei C., Valéria C. F. Barbosa, and Leonardo Uieda. "Polynomial equivalent layer." GEOPHYSICS 78, no. 1 (January 1, 2013): G1—G13. http://dx.doi.org/10.1190/geo2012-0196.1.
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We have developed a new cost-effective method for processing large-potential-field data sets via the equivalent-layer technique. In this approach, the equivalent layer is divided into a regular grid of equivalent-source windows. Inside each window, the physical-property distribution is described by a bivariate polynomial. Hence, the physical-property distribution within the equivalent layer is assumed to be a piecewise polynomial function defined on a set of equivalent-source windows. We perform any linear transformation of a large set of data as follows. First, we estimate the polynomial coefficients of all equivalent-source windows by using a linear regularized inversion. Second, we transform the estimated polynomial coefficients of all windows into the physical-property distribution within the whole equivalent layer. Finally, we premultiply this distribution by the matrix of Green’s functions associated with the desired transformation to obtain the transformed data. The regularized inversion deals with a linear system of equations with dimensions based on the total number of polynomial coefficients within all equivalent-source windows. This contrasts with the classical approach of directly estimating the physical-property distribution within the equivalent layer, which leads to a system based on the number of data. Because the number of data is much larger than the number of polynomial coefficients, the proposed polynomial representation of the physical-property distribution within an equivalent layer drastically reduces the number of parameters to be estimated. By comparing the total number of floating-point operations required to estimate an equivalent layer via our method with the classical approach, both formulated with Cholesky’s decomposition, we can verify that the computation time required for building the linear system and for solving the linear inverse problem can be reduced by as many as three and four orders of magnitude, respectively. Applications to synthetic and real data show that our method performs the standard linear transformations of potential-field data accurately.
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Takahashi, Diego, Vanderlei C. Oliveira Jr., and Valéria C. F. Barbosa. "Convolutional equivalent layer for gravity data processing." GEOPHYSICS 85, no. 6 (November 1, 2020): G129—G141. http://dx.doi.org/10.1190/geo2019-0826.1.
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We have developed an efficient and very fast equivalent-layer technique for gravity data processing by modifying an iterative method grounded on an excess mass constraint that does not require the solution of linear systems. Taking advantage of the symmetric block-Toeplitz Toeplitz-block (BTTB) structure of the sensitivity matrix that arises when regular grids of observation points and equivalent sources (point masses) are used to set up a fictitious equivalent layer, we develop an algorithm that greatly reduces the computational complexity and RAM memory necessary to estimate a 2D mass distribution over the equivalent layer. The structure of symmetric BTTB matrix consists of the elements of the first column of the sensitivity matrix, which, in turn, can be embedded into a symmetric block-circulant with circulant-block (BCCB) matrix. Likewise, only the first column of the BCCB matrix is needed to reconstruct the full sensitivity matrix completely. From the first column of the BCCB matrix, its eigenvalues can be calculated using the 2D fast Fourier transform (2D FFT), which can be used to readily compute the matrix-vector product of the forward modeling in the fast equivalent-layer technique. As a result, our method is efficient for processing very large data sets. Tests with synthetic data demonstrate the ability of our method to satisfactorily upward- and downward-continue gravity data. Our results show very small border effects and noise amplification compared to those produced by the classic approach in the Fourier domain. In addition, they show that, whereas the running time of our method is [Formula: see text] s for processing [Formula: see text] observations, the fast equivalent-layer technique used [Formula: see text] s with [Formula: see text]. A test with field data from the Carajás Province, Brazil, illustrates the low computational cost of our method to process a large data set composed of [Formula: see text] observations.
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Mendonça, Carlos Alberto, and João B. C. Silva. "The equivalent data concept applied to the interpolation of potential field data." GEOPHYSICS 59, no. 5 (May 1994): 722–32. http://dx.doi.org/10.1190/1.1443630.
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The equivalent layer calculation becomes more efficient by first converting the observed potential data set to a much smaller equivalent data set, thus saving considerable CPU time. This makes the equivalent‐source method of data interpolation very competitive with other traditional gridding techniques that ignore the fact that potential anomalies are harmonic functions. The equivalent data set is obtained by using a least‐squares iterative algorithm at each iteration that solves an underdetermined system fitting all observations selected from previous iterations and the observation with the greatest residual in the preceding iteration. The residuals are obtained by computing a set of “predicted observations” using the estimated parameters at the current iteration and subtracting them from the observations. The use of Cholesky’s decomposition to implement the algorithm leads to an efficient solution update everytime a new datum is processed. In addition, when applied to interpolation problems using equivalent layers, the method is optimized by approximating dot products by the discrete form of an analytic integration that can be evaluated with much less computational effort. Finally, the technique is applied to gravity data in a 2 × 2 degrees area containing 3137 observations, from Equant‐2 marine gravity survey offshore northern Brazil. Only 294 equivalent data are selected and used to interpolate the anomalies, creating a regular grid by using the equivalent‐layer technique. For comparison, the interpolation using the minimum‐curvature method was also obtained, producing equivalent results. The number of equivalent observations is usually one order of magnitude smaller than the total number of observations. As a result, the saving in computer time and memory is at least two orders of magnitude as compared to interpolation by equivalent layer using all observations.
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Tang, Wenwu, Yaoguo Li, Douglas W. Oldenburg, and Jianxin Liu. "Removal of galvanic distortion effects in 3D magnetotelluric data by an equivalent source technique." GEOPHYSICS 83, no. 2 (March 1, 2018): E95—E110. http://dx.doi.org/10.1190/geo2016-0668.1.
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The galvanic distortion induced by the electric charge buildup across near-surface inhomogeneities can severely affect the interpretation of magnetotelluric (MT) data for deeper structures. In addition to the methods already available, we have developed an alternative approach for processing MT impedance data with such distortions using an equivalent source technique. One prerequisite for the method is that all data are acquired on the surface, which is nearly always the case in land-based MT surveys. The method works with the electric field scaled from the impedance data and constructs an equivalent electrical polarization layer that attempts to reproduce the signal in the data while misfitting the galvanic distortion. Because of the uncorrelated characteristics of galvanic distortions across multiple stations at the same frequency, they can be distinguished and removed by constructing an equivalent source layer of electrical polarization using a regularized inverse formulation. The tradeoff between the signal and distortion is achieved through the use of generalized cross-validation method during the equivalent source construction, whereas the choice of equivalent source parameters also affects the separation. Numerical tests indicate that good results are obtained when the depth of the equivalent source layer is slightly greater than 10 times the nominal data spacing, and the lateral extent is twice that of the data area. The simultaneous processing with multiple frequencies yields more stable apparent resistivity curves than the separate single-frequency processing. The method has performed well in removing the galvanic distortions in the synthetic- and field-data examples.
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Siqueira, Fillipe C. L., Vanderlei C. Oliveira Jr., and Valéria C. F. Barbosa. "Fast iterative equivalent-layer technique for gravity data processing: A method grounded on excess mass constraint." GEOPHYSICS 82, no. 4 (July 1, 2017): G57—G69. http://dx.doi.org/10.1190/geo2016-0332.1.
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We have developed a new iterative scheme for processing gravity data using a fast equivalent-layer technique. This scheme estimates a 2D mass distribution on a fictitious layer located below the observation surface and with finite horizontal dimensions composed by a set of point masses, one directly beneath each gravity station. Our method starts from an initial mass distribution that is proportional to the observed gravity data. Iteratively, our approach updates the mass distribution by adding mass corrections that are proportional to the gravity residuals. At each iteration, the computation of the residual is accomplished by the forward modeling of the vertical component of the gravitational attraction produced by all point masses setting up the equivalent layer. Our method is grounded on the excess of mass and on the positive correlation between the observed gravity data and the masses on the equivalent layer. Mathematically, the algorithm is formulated as an iterative least-squares method that requires neither matrix multiplications nor the solution of linear systems, leading to the processing of large data sets. The time spent on the forward modeling accounts for much of the total computation time, but this modeling demands a small computational effort. We numerically prove the stability of our method by comparing our solution with the one obtained via the classic equivalent-layer technique with the zeroth-order Tikhonov regularization. After estimating the mass distribution, we obtain a desired processed data by multiplying the matrix of the Green’s functions associated with the desired processing by the estimated mass distribution. We have applied the proposed method to interpolate, calculate the horizontal components, and continue gravity data upward (or downward). Testing on field data from the Vinton salt dome, Louisiana, USA, confirms the potential of our approach in processing large gravity data set over on undulating surface.
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Mendonça, Carlos A. "Subspace method for solving large-scale equivalent layer and density mapping problems." GEOPHYSICS 85, no. 3 (May 1, 2020): G57—G68. http://dx.doi.org/10.1190/geo2019-0302.1.
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The equivalent layer technique explores an intrinsic property of potential fields that any observed field at the ground surface can be reconstituted from a fictitious continuous distribution at an arbitrary flat surface that is indistinguishable from the field of the true sources. This continuous distribution can be represented by a set of discrete cells of known position and size but unknown physical property by solving a linear system, with size proportional to the number of data points measured. The density distribution at the equivalent layer carries information about the true sources because it is a scaled and downward-continued version of the field generated by the true sources at the level that the geophysical survey was undertaken. The computation of this downward-continued field is unstable, and an equivalent source evaluation is constrained by the intense computational demand required to solve the associated large linear system. A new formulation is developed to directly solve large-scale gravity equivalent layer problems using a subspace representation for the unknown density distribution. This subspace basis is constructed by applying the singular value decomposition to the matrix containing the gridded data set. A procedure to diminish (by two orders of magnitude) the number of forward model evaluations is introduced by exploring the symmetry of the gravity kernel and its evaluation on a regular mesh. The density distribution at the equivalent layer is used to outline the spatial distribution of contrasting underlying sources, to discriminate regions with predominant positive or negative density contrast, and to estimate the mass excess or deficiency for sources with positive or negative density contrast. This technique is applied to determine density models for the Carajás airborne gravity survey and to analyze density distributions associated with banded iron formations and structures of the Carajás Mineral Province, Brazil, providing mass estimates for specific geologic unities.
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Bi Chuan-Xing, Hu Ding-Yu, Zhang Yong-Bin, and Xu Liang. "Sound field separation technique based on equivalent source method and double-layer particle velocity measurements." Acta Physica Sinica 62, no. 8 (2013): 084301. http://dx.doi.org/10.7498/aps.62.084301.
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Михеевская, Marina Mikheevskaya, Сушков, Sergey Sushkov, Бурмистрова, and Olga Burmistrova. "Dynamic analysis technique for bodies of forest motor roads." Forestry Engineering Journal 3, no. 4 (January 21, 2014): 89–93. http://dx.doi.org/10.12737/2185.
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The article describes a method of dynamic analysis of pavement bodies of timber road Ukhta – Troitsky-Pechorsk, a forecast of full sinkage and consolidation time of the subsoil. Reinforcing gravel with geogrids increases the overall (equivalent) elastic modulus of structure for 6…15 %, reduces the magnitude of the tangential stress in the layer, underlying the geogrid by 25…80 %, increases the modulus of defor-mation with significant precipitation more than in 2 times.
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Reis, André L. A., Vanderlei C. Oliveira Jr., and Valéria C. F. Barbosa. "Generalized positivity constraint on magnetic equivalent layers." GEOPHYSICS 85, no. 6 (November 1, 2020): J99—J110. http://dx.doi.org/10.1190/geo2019-0706.1.
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It is known from the potential theory that a continuous and planar layer of dipoles can exactly reproduce the total-field anomaly produced by arbitrary 3D sources. We have proven the existence of an equivalent layer having an all-positive magnetic-moment distribution for the case in which the magnetization direction of this layer is the same as that of the true sources, regardless of whether the magnetization of the true sources is purely induced or not. By using this generalized positivity constraint, we have developed a new iterative method for estimating the total magnetization direction of 3D magnetic sources based on the equivalent-layer technique. Our method does not impose a priori information about the shape or the depth of the sources, does not require regularly spaced data, and presumes that the sources have a uniform magnetization direction. At each iteration, our method performs two steps. The first step solves a constrained linear inverse problem to estimate a positive magnetic-moment distribution over a discrete equivalent layer of dipoles. We consider that the equivalent sources are located on a plane and have a uniform and fixed magnetization direction. In the second step, we use the estimated magnetic-moment distribution and solve a nonlinear inverse problem for estimating a new magnetization direction for the dipoles. The algorithm stops when the equivalent layer yields a total-field anomaly that fits the observed data. Tests with synthetic data simulating different geologic scenarios show that the final estimated magnetization direction is close to the true one. We apply our method to field data from the Goiás alkaline province, over the Montes Claros complex, in the center of Brazil. The results suggest the presence of intrusions with remarkable remanent magnetization, in agreement with the current literature for this region.
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Melnyk, V. G., P. I. Borshchov, O. D. Vasylenko, O. L. Lameko, and S. V. Dzyadevyc. "DETERMINATION OF FARADAY IMPEDANCE PARAMETERS TO INCREASE ACCURACY IN CONDUCTOMETRY AND OBTAIN ADDITIONAL DATA." Sensor Electronics and Microsystem Technologies 19, no. 3 (October 18, 2022): 38–52. http://dx.doi.org/10.18524/1815-7459.2022.3.265297.
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A simple algorithm for determining the set of parameters of the equivalent circuits of the impedance of a planar conductometric transducer with an interdigital comb topology, consisting of interelectrode and Faraday impedances is proposed. The frequency characteristics of the impedance parameters of the transducer samples and the electrical equivalent with averaged values of the parameters have been studied. A technique for determining the parameters of a three-element equivalent circuit, including solution resistance, double layer capacitance, and charge transfer resistance, has been developed and tested on a series of transducer samples. The optimal operating frequencies of the impedance-measuring channel are determined, and its schemes are developed. A technique for estimating the parameters of the Warburg impedance of transducer samples is demonstrated. The results obtained in the work make it possible to determine the optimal operating frequency range of biosensor systems and reduce errors from the influence of the Faraday impedance. The possibility of extending the functions of such transducers by using the near-electrode layer impedance parameters as informative ones is shown.
Dissertations / Theses on the topic "Equivalent-layer technique"
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Farrell, Troy W. "The mathematical modelling of primary alkaline battery cathodes." Thesis, Queensland University of Technology, 1998.
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Chang, Hsiao-Chen, and 張孝甄. "Equivalent Circuit Extraction of Embedded High-speed Interconnects by Combining FDTD method and Layer Peeling Technique." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/29438662626398788105.
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碩士國立中山大學
電機工程學系研究所
90
We proposes an efficient algorithm for extracting SPICE-compatible circuits of embedded interconnect structures from FDTD-simulated time-domain reflections. A layer-peeling technique (LPT) is used to obtain the time-domain step response of the interconnects under extract (IUE) itself. A pencil matrix method is then used to get the pole-residue representation of the time-domain step response of the IUE. A pole-reducing procedure is implemented based on a bandwidth criterion to simplify pole-residue representation. Finally, the lumped equivalent models of the IUE are synthesized by an equivalent lumped-model extraction technique, in which four types of equivalent model bases are used. The equivalent circuit can be easily implemented in SPICE-like simulator. Several transmission line structures are presented as examples to demonstrate the validity of the proposed algorithm both in time and frequency domains.
Book chapters on the topic "Equivalent-layer technique"
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Montavon, Grégoire, Jacob Kauffmann, Wojciech Samek, and Klaus-Robert Müller. "Explaining the Predictions of Unsupervised Learning Models." In xxAI - Beyond Explainable AI, 117–38. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-04083-2_7.
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AbstractUnsupervised learning is a subfield of machine learning that focuses on learning the structure of data without making use of labels. This implies a different set of learning algorithms than those used for supervised learning, and consequently, also prevents a direct transposition of Explainable AI (XAI) methods from the supervised to the less studied unsupervised setting. In this chapter, we review our recently proposed ‘neuralization-propagation’ (NEON) approach for bringing XAI to workhorses of unsupervised learning such as kernel density estimation and k-means clustering. NEON first converts (without retraining) the unsupervised model into a functionally equivalent neural network so that, in a second step, supervised XAI techniques such as layer-wise relevance propagation (LRP) can be used. The approach is showcased on two application examples: (1) analysis of spending behavior in wholesale customer data and (2) analysis of visual features in industrial and scene images.
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Phan-Thien, Nhan, and Sangtae Kim. "Load Transfer Problem and Boundary Collocation." In Microstructures in Elastic Media. Oxford University Press, 1994. http://dx.doi.org/10.1093/oso/9780195090864.003.0006.
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The acoustic and mechanical properties of cemented granular materials such as sedimentary rocks are directly related to the load transfer problem between two granules (Stoll). The theoretical description of granular materials has been based on the Hertzian contact problem between two elastic spherical inclusion in an elastic matrix, or its modifications; a review of the contact problem can be found in Johnson. In essence, the deformation problem resulting from a relative displacement between two nearby spherical elastic inclusions is studied, and the load transfer between the two is used to construct a constitutive theory for the particulate solid. In particular, Dvorkin et al. studied the deformation of an elastic layer between two spherical elastic grains, using a two-dimensional plane strain analysis similar to those of Tu and Gazis and Phan-Thien and Karihalo. They concluded that the elastic properties of the cemented system can depend strongly on the length of the cement layer and the stiffness of the cement. The main problem with the method is the assumption that the contribution to the load transfer between the granules comes from the region near contact. The assumption is well justified in the case where the Poisson’s ratio of the cement layer is 0.5 (incompressible), in which case the problem is equivalent to the corresponding Stokes flow problem where exact and asymptotic solutions are available (see, for example, Kim and Karrila). The Stokes asymptotic solution shows that the leading term in the load transfer is of O(є-1), where є is the dimensionless thickness of the cement layer. In the case where the Poisson’s ratio of the elastic layer is less than 0.5, it is not clear that the load is still strongly singular in є, and therefore a local stress analysis in the region of near contact may not necessarily yield an accurate answer, unless є is extremely small. The load transfer problem is pedagogic in that it allows us to demonstrate an effective technique often used in Stokes flow known as the reflection method, which has its basis in Faxén relations (discussed in the previous chapter).
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Williams, Keith. "Coda: The Media-Cultural Imaginary of Finnegans Wake." In James Joyce and Cinematicity, 244–55. Edinburgh University Press, 2020. http://dx.doi.org/10.3366/edinburgh/9781474402484.003.0005.
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This challenges readings of Finnegans Wake as Joyce’s turn away from film, as medium and narrative model, since its logos-focused method seems more radiophonic than cinematic, because words, voices and languages rather than images and film techniques continuously shuffle, layer, clash and blend, like criss-crossing wireless broadcasts. Nonetheless, Finnegans Wake represents further experimental ekphrasis, because Joyce ‘retrofitted’ older technological influences while engaging with film’s successor: early television. The lantern’s dissolving views can be regarded as ‘visual palimpsests’, one picture shimmering through the outlines and interstices of another. Joyce’s verbal equivalent reached its hypostasis in Finnegans Wake’s ‘verbal dissolves’, as forms and meanings continually morph in and out of each other, like multi-layered images or filmic cross-fades and superimpositions. Joyce carries this process into the future by mixing different television broadcasts and questioning the medium’s potential power. Additionally, Stuart Gilbert’s short film treatment of ‘Anna Livia Plurabelle’ employed animation effects which shed a very suggestive light on the ‘morphing’ techniques implicit in Joyce’s method. With an imagination saturated by visual forms, Joyce remained well capable of viewing moving pictures in the projection box of his mind and translating them into his ‘moving dream panorama’.
Conference papers on the topic "Equivalent-layer technique"
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Siqueira, F. C. L., V. C. Oliveira Jr, and V. C. F. Barbosa. "Iterative Fast Equivalent-layer Technique." In 79th EAGE Conference and Exhibition 2017. Netherlands: EAGE Publications BV, 2017. http://dx.doi.org/10.3997/2214-4609.201701077.
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Reis, Andre L. A., Vanderlei C. Oliveira, and Valeria C. F. Barbosa. "Equivalent layer technique for estimating magnetization direction." In SEG Technical Program Expanded Abstracts 2019. Society of Exploration Geophysicists, 2019. http://dx.doi.org/10.1190/segam2019-3216745.1.
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Piauilino, Larissa S., Valeria C. F. Barbosa, and Vanderlei C. Oliveira. "Fast equivalent-layer technique for magnetic data processing." In SEG Technical Program Expanded Abstracts 2020. Society of Exploration Geophysicists, 2020. http://dx.doi.org/10.1190/segam2020-3428252.1.
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Piauilino, Larissa S., Fillipe C. L. Siqueira, Vanderlei C. Oliveira, and Valeria C. F. Barbosa. "Estimative of gravity-gradient tensor components via fast iterative equivalent-layer technique." In SEG Technical Program Expanded Abstracts 2019. Society of Exploration Geophysicists, 2019. http://dx.doi.org/10.1190/segam2019-3215804.1.
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Monden, Kenji. "Effect of Percolation on Equivalent Thermal Conductivity of Insulating Layer in Insulated Metal Substrates." In ASME 2003 International Electronic Packaging Technical Conference and Exhibition. ASMEDC, 2003. http://dx.doi.org/10.1115/ipack2003-35175.
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An insulated metal substrate (IMS) is a circuit board comprising an insulating layer on a metal base plate. The insulating layer is made from epoxy resin incorporating dense inorganic fillers with high thermal conductivity. Because the substrates have high thermal conductivity, they are used in applications where electric parts generate intense heat, such as inverters, amplifiers, motor drivers and so on. It is expected that the insulating layer has higher thermal conductivity as the use of an IMS is expanded. Therefore, the influence of percolation on the equivalent thermal conductivity of an insulating layer is considered. The effect of the volume fraction of inorganic filler on the equivalent thermal conductivity of insulating layer in IMS is experimentally investigated. The equivalent thermal conductivity of insulating layer as a function of volume fraction of filler is estimated by FEM and Monte Carlo technique together. The acquired value of percolation threshold volume fraction is the same grade as the previous reported value. Based on these experimental and numerical results, an effective thermal conductivity of a filler which contains surrounding interfacial region is evaluated. The effective thermal conductivity of an irregular filler is presumed smaller than that of a spherical filler. It is noted that the control of filler size and shape is important for the formation of high thermal conductivity of an insulating layer. In addition, an improved equation for the equivalent thermal conductivity of insulating layer in IMS is proposed. The predictive values from the equation for insulating layer in an improved IMS agree with experimental results.
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Lau, Chi Ho, and S. W. Ricky Lee. "Fabrication of Nanoscale Vias by Offset Patterning." In 2008 Second International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2008. http://dx.doi.org/10.1115/micronano2008-70131.
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Patterning of features with photolithography technique by overlying multiple exposure patterns with intentional offset reduces the effective size of the resultant opening when the openings overlap incompletely. The size of resultant opening depends on the size of the parental opening and the degree of overlap. Overlapping via patterns helps to achieve small via size from photolithography. In the present study, two oxide layers with via pattern were involved. The bottom oxide layer was deposited and patterned first. The top oxide layer and the poly-Si sandwich layer were then deposited on the patterned bottom oxide layer and patterned with an offset afterwards. Experimental results show resultant vias with size reduction by more than 50% compared with the parental vias. The equivalent diameter of the resultant vias goes down to as small as 400 nm. It was found that the equivalent diameter decreases with reduction in parental via size. The length-to-width ratio of the resultant vias opening increases as the parental via size becomes larger. The offset distance is also found to contribute significant effect to the size of the resultant via. The large offset distance leads to small but high-aspect ratio resultant vias.
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Fei, Kai, Tzer-Shing Chen, and Che-Wun Hong. "Thermal Lattice Boltzmann Simulation of Two-Phase Flow at the Anode Microchannel of Micro Direct Methanol Fuel Cells." In ASME 2008 First International Conference on Micro/Nanoscale Heat Transfer. ASMEDC, 2008. http://dx.doi.org/10.1115/mnht2008-52094.
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Carbon dioxide bubble removal in anode diffusion layer is a critical technique in micro direct methanol fuel cells (μDMFCs) [1, 2]. By deriving a thermal lattice-Boltzmann model, we investigate the hydrophilic, thermal and geometric effects on the two-phase flow (CO2 bubbles in methanol-water solution) in a microchannel of a μDMFC. The dimension of the example microchannel is similar to the diffusion layer. The length is 15.9 μm while the width (or height) is 1.5 μm, which are equivalent to the averaged pore size of the porous diffusion layer. A two-dimensional, nine-velocity (D2Q9) thermal lattice-Boltzmann model (TLBM) was derived in this paper.
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Mandelis, A., J. A. Garcia, and B. Farahbarhsh. "Photothermal Radiometry of Thermal Spray Coatings: Thermophysical Properties and Disbonding Effects Characterization." In ITSC 2000, edited by Christopher C. Berndt. ASM International, 2000. http://dx.doi.org/10.31399/asm.cp.itsc2000p1281.
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Abstract Laser infrared photothermal radiometry (PTR) can be used to determine the thermophysical properties (thermal diffusivity and conductivity) and interfacial defects (i.e. disbonding) of various thermal sprayed coatings on carbon steel substrates. PTR experimental results are compared with a one-dimensional photothermal model that can take into account roughness affects and interfacial defects by considering a roughness equivalent-layer and an equivalent-thermal resistance, respectively. The foregoing thermophysical parameters of the thermal sprayed coatings are obtained when a multi-parameter optimization algorithm is used to fit the PTR experimental results. The potential of the PTR technique for in-situ monitoring of the coating process and the characterization of the thermal sprayed coatings will be discussed in this paper.
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Yi, Yuliang, Shenglin Ma, Xiaomei Yu, Ming Liu, and Xiaohua Liu. "A Bulk Micromachined Cantilever Array for Uncooled Infrared Imaging." In 2008 Second International Conference on Integration and Commercialization of Micro and Nanosystems. ASMEDC, 2008. http://dx.doi.org/10.1115/micronano2008-70109.
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This paper presents a bi-material microcantilever focal plane array (FPA) for uncooled infrared (IR) imaging. The FPA was fabricated by a bulk silicon micromachining method with substrate silicon selectively removed by deep reactive ion etching (DRIE) technique at the area where each cantilever pixel is located. The absorbance of the IR radiation can be improved by 48% due to the selective removal of the substrate, and hence the noise equivalent temperature difference (NETD) of the FPA can be reduced by 32% compared to the one fabricated by sacrificial layer technique, approaching 60mK. The thermomechanical sensitivity and the response time of the FPA were measured and calculated to be 112nm/K and 15ms, respectively. An image of human bodies was captured by an optical readout method.
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Maneepan, K., R. A. Shenoi, H. K. Jeong, and J. I. R. Blake. "Multi-Objective Optimisation of Orthogonally Tophat-Stiffened Composite Laminated Plates." In 25th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2006. http://dx.doi.org/10.1115/omae2006-92442.
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This paper deals with the multi-objective optimisation of an orthogonally tophat-stiffened composite laminated plate. The plate is simply supported around all its edges and subjected to a uniform lateral pressure load. Genetic algorithm (GA) technique is employed as the optimisation tool. As objective functions, both structure weight and manufacturing cost, with respect to a set of practical stiffness and strength constraints (maximum stress criterion), are considered. Structural analysis of the plate is performed using a combination of elastic grillage solutions and an equivalent elastic property approach. Through the unique solutions in conjunction with the GA, it is possible to produce layer by layer optimisation results for the laminated plate, the web, the crown and the overlaminate of the plate. Therefore, the present optimisation framework is capable of dealing with a large number of design variables such as different fibre materials, fibre volume fractions, fibre orientations and geometric values.